The administration of immune checkpoint inhibitors (ICIs) often leads to immune-related adverse events. However, their effect on auditory function is largely unexplored. Thorough preclinical studies have not been published yet, only sporadic cases and pharmacovigilance reports suggest their significance. Here we investigated the effect of anti-PD-1 antibody treatment  on hearing function and cochlear morphology in C57BL/6J mice. ICI treatment did not influence the hearing thresholds in click or tone burst stimuli at 4–32 kHz frequencies measured by auditory brainstem response. The number and morphology of spiral ganglion neurons were unaltered in all cochlear turns. The apical-middle turns (<32 kHz) showed preservation of the inner and outer hair cells (OHCs), whilst ICI treatment mitigated the age-related loss of OHCs in the basal turn (>32 kHz). The number of Iba1-positive macrophages has also increased moderately in this high frequency region. We conclude that a 4-week long ICI treatment does not affect functional and morphological integrity of the inner ear in the most relevant hearing range , but a noticeable preservation of OHCs and an increase in macrophage activity appeared in the >32 kHz basal part of the cochlea. Activation of cellular immunity and abolishment of self-tolerance against tumor cells in the host organism  is an efficient and preferred way of antitumor pharmacotherapy with growing clinical applications and expanding therapeutic indications.According to the cancer immunoediting hypothesis, one of the mechanisms tumor cells use to escape from immunosurveillance is to establish an immunosuppressive microenvironment by production of adenosine  or expreHowever, activation of the immune system often causes atypical side effects, called immune-related adverse events (irAE). The immunological imbalance may lead to uncontrolled immune responses and breakdown of the peripheral tolerance, resulting in autoimmune-like symptoms. The most common irAEs involve gastrointestinal, dermatologic, hepatic, and endocrine toxicities. Less frequently, symptoms affecting the lung, eye, kidney, pancreas, the nervous, and the hematopoietic system are reported, as well ,9,10,11.Publications on cases of audiovestibular adverse events are much more sporadic ,13,14 anIn recent years it has become clear that the inner ear is not an immune privileged organ ,16. It cOur aim was to investigate the alterations, if any, caused by PD-1 inhibitor monoclonal antibody treatment in the hearing function and cochlear morphology. To this end, we used a murine model and connected the functional auditory brainstem response (ABR) measurements with histopathological examinations: Cochlear whole-mount dissections to evaluate hair cell numbers, hematoxylin/eosin (HE) staining on mid-modiolar sections to detect changes in spiral ganglion neuron (SGN) numbers and structure, and Iba1 immunohistochemistry to compare the number of activated cochlear macrophages between the treated and control group. We found a preserved function and morphology in the most relevant hearing range (4–32 kHz) and in the corresponding apical-middle cochlear turns, and an enhanced outer hair cell (OHC) survival in the high-frequency basal turn with a moderate increase in the number of Iba1-positive macrophages.To investigate whether anti-PD-1 antibody therapy has an effect on the function of hearing, hearing thresholds of isotype control, anti-PD-1 antibody-treated mice were determined and compared at the end of the treatment period. There were no statistically significant differences either by broadband click or frequency-specific pure tones at frequencies 4–32 kHz . Both grCochleograms, plotted with the evaluation of the staining of actin filaments in inner and outer HCs by Alexa Fluor 594 Phalloidin and counterstaining of nuclei with 4′,6-diamidino-2-phenylindole (DAPI), showed that there is no hair cell loss in the ≤32 kHz frequency range in either treatment groups. However, anti-PD-1 antibody treatment mitigated the loss of OHCs at frequencies higher than 32 kHz A,B,E,F. There was no alteration in SGN number and morphology after anti-PD-1 antibody treatment in either the apical, middle, or the basal cochlear turns on HE staining of cochlear sections .Iba1-positive macrophages were detected mainly in the Rosenthal’s canal, along the peripheral processes of the SGNs, in the stria vascularis and the spiral ligament as presented in The role of the immune system in hearing and hearing losses is in the focus of auditory research ,25,26. PIn our mouse model the 4-week long mouse-specific anti-PD-1 therapy did not affect the function of hearing in the 4–32 kHz frequency range and the number of IHCs and OHCs in the apical-middle cochlear turns (<32 kHz). This is in accordance with a murine study by Spielbauer et al. who found that the PD-1 inhibitor monotherapy had no impact on hearing thresholds between 8–40 kHz and on hair cell numbers in the range of 8–32 kHz. However, the Spielbauer study did not investigate the effect of PD-1 inhibition on SGNs and cochlear immune response , on the numbers of hair cells in the high frequency regions (>32 kHz) and did not use isotype antibody for control . Kuzucu On the other hand, these ABR results are in contrast with the observations of three case reports, where sudden bilateral hearing loss was detected at high frequencies following PD-1 inhibitor treatment ,13,14. FImmune activation in the cochlea may also be associated with SGN injury ,50. The The C57BL/6J strain shows age-related hearing impairment with an increase in hearing thresholds and OHC loss expanding from basal part of the cochlea toward the apical region ,52. LossThe observed OHC preservation in the high frequency range of the cochleogram (>32 kHz) was accompanied with the increased number of Iba-1-positive macrophages exclusively in the basal cochlear turn after anti-PD-1 treatment. According to the literature, macrophages from different cochlear turns show different phenotypes and response patterns to hair cell degeneration in age-related hearing loss (AHL)  and onlyThe enhanced macrophage activity may be responsible for the mitigated OHC loss in the basal turn with mechanisms similar to those that reduced pathology and improved memory in the Alzheimer’s disease (AD) murine model after a PD-1 immune checkpoint blockade. AHL is partly contributed to chronic, low-grade inflammation in the cochlea, consisting of failure in downregulation of proinflammatory proteins and accumulation of cell debris resulting from insufficient elimination. In AD, amyloid-β (Aβ) accumulation leads to a chronic stimulation of the immune system which initiates a vicious circle: Cytokines such as interleukin 1-β, IL-6, and tumor necrosis factor-α stimulate the synthesis of β-amyloid precursor protein and Aβ peptides . The bloDespite the fact that overactivation of the immune system is involved in the pathology of sensorineural hearing losses, the revolutionary anti-PD-1 therapy with an immunostimulatory effect does not seem to have a significant impact on the functional and morphological integrity of the inner ear in the most relevant hearing range. The immune blockade of PD-1 does not lead to hearing loss or worsening of the pre-existing hearing impairment in the apical-middle turns (<32 kHz). Moreover, a noticeable preservation of OHCs appears in the high frequency (>32 kHz) basal part of the cochlea. Our findings also demonstrate the Janus face of immuno-pharmacotherapy.Experimental procedures were carried out on male C57BL/6J mice , ranging from 8 to 10 weeks of age at the beginning of the study. Mice were maintained under a 12:12 h light–dark cycle under controlled environmental conditions (20–24 °C and 35–75% relative humidity) in individually ventilated cages with shelters, holding 2–3 animals per cage. Standard rodent chow and tap water were provided ad libitum throughout the entire duration of the experiment. All procedures were approved by the National Scientific Ethical Committee on Animal Experimentation and the Semmelweis University’s Institutional Animal Care and Use Committee  in accordance with NIH guidelines , Guide for the Care and Use of Laboratory Animals: Eighth Edition) and permitted by the government of Food Chain Safety and Animal Health Directorate of the Government Office for Pest County .n = 10) or an anti-PD-1 antibody-treated group . Purified InVivoMAb rat IgG2a isotype control antibody (clone 2A3), and in addition, InVivoMAb anti-mouse PD-1 antibody (clone RMP1-14), used for immune checkpoint blockade were purchased from BioXCell. Drugs were administered once on the day of treatments by intraperitoneal (i.p.) injections at a dose of 200 μg/mouse/treatment. Antibodies were delivered to mice three times per week over the treatment period lasting for 4 weeks  in phosphate-buffered saline , then immersed in the 4% PFA for 2 h at room temperature in Eppendorf tubes on a rocking shaker. Cochleae were then decalcified in 5% EDTA in PBS with 0.4% PFA in 15-mL centrifuge tubes for 6 days at room temperature on a rocking shaker. The EDTA solution over the cochleae was changed daily.The organ of Corti was removed from the decalcified right cochleae of 6 control and 6 anti-PD-1 antibody-treated animals under stereomicroscope using microsurgical instruments. The bony wall, the vestibular system, spiral ligament, modiolus, and tectorial membrane were carefully removed, and the basilar membrane was cut into 3–6 longitudinal segments. The samples were rinsed three times in PBS for 5 min each time, then immersed in 0.3% Triton X-100 in PBS for 10 min and incubated with Alexa Fluor 594 Phalloidin  for 40 min at room temperature. After washing 3 times with PBS for 5 min, nuclei were stained with DAPI . Subsequently, samples were washed 3 times in PBS for 5 min. Finally, cochlear turns were placed on a glass slide using Prolong Gold antifade reagent .n = 6) and anti-PD-1-treated groups (n = 6), cochleograms were plotted. The frequency-place equation by Müller et al. (2004) was used to correlate the location to frequency. For statistical analysis, the evaluated section of the basilar membrane was divided into three equal segments in length: apical, middle, and basal.Hair cells were imaged in the epifluorescent mode of a Leica LMD6 microscope coupled to a CCD camera  using a 40× HC PL Fluotar objective . Cells were counted manually. In every 190–250 µm segment alongside the pillar cells the number of missing hair cells was counted. Hair cell counts were analyzed using a customized version of the Kresge Hearing Research Institute CytoGram Program, Version 3.0.6 . An average of 95% of the total length of the basilar membrane from the apex was evaluated. In both the control  was used to dehydrate the decalcified tissues. Further dehydration with a graded series of ethanol  and xylol treatment (2 × 1 h) were performed in a Leica TP 1020 tissue processor . Ultimately, the cochleae were embedded in 60 °C paraffin, and 4-µm sections were cut with a Leica HistoCore MULTICUT microtome  for hematoxylin/eosin (HE) and Iba1 staining.2 in average, but min. 6000 µm2) in four anti-PD-1-treated (2 left and 2 right ears) and four control (2 left and 2 right ears) animals. Five sections per mouse were evaluated and the average density of SGNs was calculated in the apical, middle, and basal turns.To avoid repeated counting of the same SGNs, every fourth section was stained with HE . Images of the Rosenthal’s canal were acquired in the brightfield mode of a Leica LMD6 microscope  using a 40× HC PL Fluotar objective . SGNs were counted in a representative area  containing 2.5% non-fat dried milk powder in PBS for 1 h at room temperature, then incubated with the primary antibody  overnight at 4 °C. After washing 3 times for 10 min in PBS, secondary antibody was used SignalStain® Boost IHC Detection Reagent  in accordance with the manufacturer’s instructions, and washed again. The specific signal was developed with ImmPACT DAB EqV Substrate Kit , dehydrated, and covered by coverslips using CV Mount . Iba1 positive cells were evaluated in an observer-blinded fashion by two independent persons in 6 control  and 6 anti-PD-1 antibody-treated  4-µm sections.The 4-µm modiolar sections were deparaffinized and hydrated with xylene and a graded series of ethanol solutions, respectively. Heat-induced antigen retrieval was performed in microwave-heated citrate buffer (pH ≈ 6.5) for a total time of 10 min . The slides were cooled, washed in PBS for 3 × 5 min, then the endogenous peroxidase activity was blocked with 3% HData were analyzed with two-way ANOVA followed by a Bonferroni post-hoc comparison test using the 8.4.3 version of GraphPad Prism. Results are indicated as mean ± standard error of the mean (SEM).


In the personalisation of hearing-aid fittings, gain is often adjusted to suit patient preferences using live speech. When using brief sentences as stimuli, the minimum gain adjustments necessary to elicit consistent preferences (“preference thresholds”) were previously found to be much greater than typical adjustments in current practice. The current study examined the role of duration on preference thresholds.Participants heard 2, 4 and 6-s segments of a continuous monologue presented successively in pairs. The first segment of each pair was presented at each individual’s real-ear or prescribed gain. The second segment was presented with a ±0–12 dB gain adjustment in one of three frequency bands. Participants judged whether the second was “better”, “worse” or “no different” from the first.Twenty-nine adults, all with hearing-aid experience.The minimum gain adjustments needed to elicit “better” or “worse” judgments decreased with increasing duration for most adjustments. Inter-participant agreement and intra-participant reliability increased with increasing duration up to 4 s, then remained stable.Providing longer stimuli improves the likelihood of patients providing reliable judgments of hearing-aid gain adjustments, but the effect is limited, and alternative fitting methods may be more viable for effective hearing-aid personalisation. In the treatment of hearing loss, clinicians fit hearing-aids to reach a balance between audibility and comfort for each patient. The balancing begins with prescribed gains across frequency based on each patient’s pure-tone thresholds. These prescribed gains, based on average data, are then personalised through adjustments made by the clinician using patient feedback . The patWe have previously investigated what gain adjustments are discriminable for short sentences presented in quiet. Median just-noticeable differences (JNDs) for increases in gain (increments) in broad low-, mid- and high-frequency bands were 4, 4, and 7 dB, respectively . Gain adPrevious psychophysical research provides some evidence that speaking longer would lead to more consistent preferences: level discrimination improves with increasing duration, albeit mostly limited to short pure-tone stimuli. Increasing the duration of a 0.25, 1, or 8-kHz tone up to 0.5, 1, or 2 s, respectively, can improve level discrimination for normal-hearing listeners . FurtherIn sound-quality evaluations such as comparing hearing-aid settings, a balance must be struck in sound-sample duration. The sample must be long enough to allow perception of the acoustic changes, but short enough to allow comparison of the adjusted sound with the previous (reference) sound. The International Telecommunication Union (ITU) recommendations for subjective sound-quality evaluations note that, for paired comparisons, durations should not exceed 15–20 s due to “short-term human memory limitations”, but can be “a few seconds” . These mOn the basis of the foregoing evidence, we hypothesised that increasing the duration of the stimuli would elicit more consistent and reliable preferences for gain adjustments. The current study used most of the same methods, including most of the same participants, as Twenty-nine adults  were recruited from a sample who had previously participated in a gain-discrimination experiment . The medFor the 19 participants who habitually wore hearing-aids at the time of the study, the real-ear insertion gain provided by their hearing-aids in their better ear was measured with 65 dB broadband noise input  to provide an estimate of their cognitive abilities  of either −12, −6, 0, +6, and +12 dB was applied in one of three broad frequency bands: a low-frequency band combining 0.25 (low-pass) and 0.5 kHz (octave) bands (LF), a mid-frequency band combining 1 and 2 kHz octave bands (MF), and a high-frequency band combining the 4 kHz and 6 kHz (high-pass) bands (HF). Stimuli were generated by convolving each segment with a 140-tap finite impulse response filter optimised for NAL-R equalisation at 24-kHz sample rate by F = 13.06 and 19.41, respectively]. The differences, however, were small; absolute differences in band-specific level increased from 0.2 dB for the LF band to 0.3 dB for MF and HF bands , and absolute level differences decreased from 0.3 to 0.2 to 0.1 dB when the duration increased from 2 to 4 to 6 s, respectively .We additionally analysed the effect of the natural variation in power within bands across the consecutive segments of each trial (i.e. when ΔGain = 0). There were significant mean absolute level differences within bands between the two segments in any given trial as a function of both frequency band and segment duration  and 4 to 6 s . The greatest rates of “better” and “worse” responses were for LF adjustments.The proportions of “better” (B), “worse” (W) and “no difference” (ND) judgments were calculated for each gain adjustment in each frequency band . A repeat(59) = 3.11 and −3.10 for better and worse, respectively; Holm-Bonferroni corrected p′ = 0.0028 and 0.0030] and HF band . There were also more “better” and less “worse” ratings for the LF band for +12 dB adjustments in the current study compared to the previous (compare grey with coloured triangles in the left panel of (59) = 1.99 and −1.60; both p > 0.05].As the current methods shared many aspects, including participants, with p = 0.0017].Participants were less prone to choose “no difference” when there was no gain adjustment in the current study compared to the previous study. The proportion of no difference responses at ΔGain = 0 was 0.84 across segment durations compared to 0.94 previously for short sentences  which corresponds to ion task . Shapiroη2 = 0.11) interaction between gain direction and duration; preference thresholds decreased with increasing duration more for increments than decrements. There was additionally a significant but modest three-way interaction in the RMANOVA: preference thresholds for the MF band decreased with increasing segment duration more for decrements than for increments.An RMANOVA based on the preference thresholds showed main effects of frequency band, direction of gain adjustment and segment duration . PrefereMean thresholds with 95% repeated-measures confidence intervals  are showt = 2.75 and 2.49; p′ = 0.011 and 0.030, respectively). Thresholds for 2-s stimuli, averaged across frequency bands, were positively correlated with thresholds in the previous study for both increments and decrements . Preference thresholds were not correlated with age, BE4FA, or hearing-aid experience . HF increment preference thresholds were positively correlated with HF pure-tone thresholds , and negatively correlated with HF sensation level  and cognitive score . Individual 2-s preference thresholds were correlated with individual decreases in threshold with duration, characterised as the slope in dB/s . Individual 2-s, 4-s or 6-s preference thresholds were not correlated with individual cognitive scores , but slopes (dB/s) were correlated with cognitive scores . Controlling for the variance shared with 2-s thresholds, individual slopes were still correlated with cognitive scores . That is, thresholds decreased more with duration (i.e. greater negative slope) for those with lesser letter/digit-monitoring ability. Based on this correlation, the RMANOVA of preference thresholds was re-run with centred cognitive scores as a covariate. As expected, the covariate reduced the error term, increasing the F statistics and η2 effect sizes, but did not change the pattern of results shown in The preference thresholds measured here for 2-s consecutive segments of a continuous story were similar to the thresholds for short sentences reported by κ ], 0.50 (0.47–0.53) and 0.50 (0.47–0.53) for segments of 2-s, 4-s and 6-s duration, respectively, representing “fair” (2 s) and “moderate” (4 and 6 s) agreement. That is, agreement significantly increased from 2 to 4 s, but not from 4 to 6 s.Fleiss’ κ  was usedW = 0.92, 0.90 and 0.92 for 2-s, 4-s and 6-s stimuli), non-parametric tests were used to compare reliability across conditions. χ2 = 11.10; p = 0.011]. There was no significant difference in reliability between sentences and 2-s segments  nor between 4-s and 6-s segments . The percentage of participants with ≥90% reliable preferences, however, did increase from 14% at 4 s to 28% at 6 s. Individual reliabilities for short sentences and 2-s stimuli were not correlated, but reliabilities for 4-s and 6-s stimuli were .A participant’s judgments  for a given gain adjustment in a given frequency band were considered reliable if seven or more of those judgments were identical, a reliability threshold based on binomial probability theory . IndividBy having participants compare and judge consecutive segments of a single-narrator story, we have shown that longer durations promote more frequent and reliable “better” or “worse” preference judgments for gain adjustments in broad frequency bands. That is, the gain adjustments required to elicit consistent preferences decreased with increasing stimulus duration. The proportions of better or worse preferences were greater, so preference thresholds were smaller, for increments than for decrements, in agreement with Despite differences in the method, the median preference thresholds in the current study for 2-s segments were similar to the thresholds for 1.6-s average duration sentences in our previous study , and indParticipants were less likely to respond “no difference” in the current study when consecutive segments were presented without gain adjustments compared to the previous study  where thz = 2.72 and 2.13; p = 0.0065 and 0.032, respectively); all other threshold differences were not significantly different from zero . Further, excluding trials based on extreme variation between their consecutive segments did not have any effect on the rate of change of preference thresholds as a function of duration. Thus, there is scant evidence that the natural variation in the consecutive stimuli affected the pattern of results.The use of an ongoing story, as opposed to hearing the same utterance twice, anecdotally provided a greater degree of participant engagement with the material, engagement as might occur in the clinic, where the responses of the patient will affect real-world use. Any greater engagement with the stimulus content, however, may have been detrimental to performing the task. Beyond the decrease in no-difference responses, the effect of comparing different stimuli (two consecutive segments) versus comparing identical stimuli was small. Using non-repeating segments introduces variability in the level and spectrum in the comparison, which can decrease detectability , thus inThe delivery of stimuli used for appraisal by the patient in the clinic may be different to paired or sequential comparisons. Rather, the appraisal may take the form of a single interval. Single interval ratings of hearing-aid sound quality have shown moderate test-retest reliability  and goodIt is not known if durations > 6 s would provide even greater discriminability and more reliable preferences. While the thresholds across most conditions decreased significantly from 4 s to 6 s, the effect was small. The overall rate of change decreased from −0.8dB/s between 2 and 4 s to −0.4dB/s at 6 s, resembling the exponential decay in memory-based models of the effects of duration on pairwise comparison e.g. . There wThe improvement in thresholds and reliability with increasing stimulus duration was small relative to the thresholds and reliabilities themselves. Talking or presenting stimuli for 6 s to a hearing-aid wearer in the clinic would help elicit consistent preferences for adjustments, but those adjustments would still need to be large: 3-6 dB for increments, 5-12 dB for decrements. These thresholds are well above common troubleshooting adjustments, especially for adjustments at higher frequencies. A patient may indeed state an immediate preference when a smaller adjustment has been made, but such a preference should be treated with caution, as it may not be based on the acoustical percept of the adjustment, and is therefore likely to be unreliable. For the personalisation of hearing-aids in the clinic, it is therefore important not only to say more than a few words (e.g. “how’s that sound?”) immediately following an adjustment, but also to ensure that the adjustment is large enough to elicit a consistent effect. Given these constraints, alternative methods of fitting, such as self-adjustments , which h


Growth hormone (GH) plays an important role in auditory development during the embryonic stage. Exogenous agents such as sound, noise, drugs or trauma, can induce the release of this hormone to perform a protective function and stimulate other mediators that protect the auditory pathway. In addition, GH deficiency conditions hearing loss or central auditory processing disorders. There are promising animal studies that reflect a possible regenerative role when exogenous GH is used in hearing impairments, demonstrated in in vivo and in vitro studies, and also, even a few studies show beneficial effects in humans presented and substantiated in the main text, although they should not exaggerate the main conclusions. Hearing begins when the hair cells (HC) located in the cochlea perceive the sound stimulus. This sensory organ transduces the mechanical energy received for its transformation into electrical energy. The auditory pathway is responsible for the transmission of these acoustic signals to the brain, where the information received is processed for conscious perception. This path (afferent) has an opposite path (efferent) from which the received signal is regulated or inhibited. Both routes experience multiple interhemispheric crossings during their trajectory . The phyIn addition to the effects of GH/IGF-I on normal brain development and functioning, this system is also involved in the repair processes of the brain after injury, as many studies have already shown good results after GH administration to experimental animals ,15,16,17Given the significant effects of GH on the brain, it seems logical that this hormone also plays a significant role in the auditory pathway. Even and given that GH secretion experiences a continuous decrease from approximately 20 years to being practically undetectable around 60 years of age , it is fPhysiologically, the loss of hair cells (HC) begins in the early stages of life, and they can be clinically observed from the fifth decade of life ,29. TherIn this study we will analyze the role of GH in hearing and the physiological pathways that it regulates, as well as some syndromes related to GH that directly or indirectly condition hearing loss. Finally, we will assess the therapeutic potential of GH in the treatment of auditory pathology.Although it had been postulated that GH could be a neurohormone given its cerebral expression , most ofStudies in animal models have shown the relevance of GH in the development of the organs of the inner ear. During the embryonic period, the chicks express high GH immune reactivity in the vesicles that will develop the inner ear . During Interestingly, hearing is directly related to the growth rate in children and adolescents. In fact, the hearing threshold in infancy can predict growth rate . There aAdults with untreated, congenital lifetime isolated GH deficiency usually show predominance of mild high-tones sensorineural hearing loss . NeurophBoth GH deficiency and excess involve an alteration in central auditory processing, leading to cognitive deficits. GH-deficient subjects show an increase of the acoustic P300 latency, whereas in those with acromegaly there is a reduction in the amplitude of this wave, which also conditions cognitive impairment . Brain tAll of the evidence described above demonstrates that GH plays a major role in the entire auditory pathway, corroborating the findings about untreated GH deficient children and hearing loss .The fact that noise damages the auditory pathway is undoubted, but the mechanisms by which this occurs are not yet well known. The effects of noise on the auditory pathway usually appear rapidly, damaging synapses, inducing the appearance of reactive oxygen species (ROS), calcium accumulation, and recruiting inflammatory mediators (such as IL-6 or TNF) and increasing glutamate excitotoxicity. Noise activates several pathways including caspase or JNK/MAPK dependent and independent pathways ,47,48. NA series of studies showed that prolonged exposure to high intensity noise initially upregulates GH expression , increasBased on these results, it seems that after exposure to noise, GH can play an important role in neuroprotection and neuroregeneration, at least in animal models, so the next step is to consider whether exogenous GH could exert viable clinical effects to regenerate the auditory pathway.In vivo and in vitro studies have tried to analyze whether GH could protect, recover or even regenerate cells involved in hearing. The first studies focused on observing the ability of GH to successfully stimulate the proliferation of cultured outer ear cartilaginous structures (chondrocytes) of rabbits, showing positive results suggesting that GH directly initiates proliferation in rabbit ear chondrocytes and, consequently, in mammals .However, few reports have demonstrated the efficacy of exogenous GH in hearing. In fact, one might even wonder if treatment with this hormone may pose a risk of hearing impairment since, theoretically, the increase in GH induces greater ossification of the ear cavities that could worsen auditory transmission, as apparently seen in acromegaly . HoweverA brain injury, such as traumatic brain injury or cerebral palsy, can lead to a deficit of GH, which implies a replacement treatment with this hormone that, as previously mentioned, is safe and effective in brain repair. In fact, as our group demonstrated, GH treatment is able to restore hearing in patients with cerebral palsy and hearing loss . Its mecThe therapeutic potential of GH for use in other conditions such as ischemia, noise-induced hearing damage, or drug toxicity needs to be evaluated but appears promising. Early treatment is undoubtedly a factor to ensure its success .GH administration can stimulate the proliferation of HC after cochlear damage. Zebrafish has been the most studied species of all animal models due to the inherent ability of this fish to induce neuroregeneration. In zebrafish, the use of GH antagonists leads to a significant decrease in cell proliferation in the inner ear. Faced with a stimulus that generates cochlear damage, and damage to hair cells, endogenous GH can increase its expression, to stimulate the regeneration of those auditory hair cells. GH mRNA expression in this case is located perinuclearly around erythrocytes in the blood vessels of the inner ear epithelium. After overexposure to noise, the densities of the saccular hair cells in the GH-treated treated fish were similar to those of the controls, and higher than those of the fish that received buffer. With the use of exogenous GH, cell proliferation was stimulated and apoptosis was reduced in the saccules, lagenae and utricles of the fish treated from the day after acoustic trauma ,67.Another study has focused on evaluating the effects on nerve regeneration of neurons of the spiral ganglion, a group of bipolar cell bodies that innervate the ciliated cells of the organ of Corti and project axons to the cochlear nerve. This in vitro study showed that exposure to different concentrations of GH induces branching and cell growth. Regarding an effect of GH on neuronal survival, while it increased after the combined administration of GH and BDNF (Brain Derived Nerve Factor), the administration of only GH failed to reproduce this effect .The hippocampus is an area of special interest in the auditory pathway since neural circuits connect to this brain structure. Neurons in the hippocampus respond to to action potentials generated in the inner ear following sound stimuli and are not tonotopically organized . During There is a promising prospect for the recovery of auditory processing in GH-deficient patients through the use of GH replacement therapy. Such is the case in patients with Sheehan syndrome. These patients have panhypopituitarism resulting from an infarction of the pituitary gland due to hypovolemic shock or severe hemorrhage. Neurophysiological studies show that the administration of GH decreases the prolongation of P300 latencies after six months of treatment . GH treaAs mentioned in the Introduction, it is well established that GH gene expression occurs in many tissues and organs, including the central and peripheral nervous system, and this expression is independent of that which occurs in the pituitary gland. GH administration is capable of increasing axonal regeneration, promoting reinnervation, maintaining or inducing Schwann cells proliferation, and reducing muscle atrophy; all this translates into great potential for the treatment of peripheral nerve injuries ,76,77,78The neuroprotective and neuroregenerative effects of GH are carried out: 1) by the direct action of this hormone, or 2) by inducing the expression of neurotrophic factors. The direct action of this hormone begins after the binding of GH to its receptor, which leads to the activation of the JAK/STAT signaling pathway, considered as the main intracellular transduction system of the effects of GH, although also the signaling pathways PI3K/Akt, MAPK and Notch are activated by the hormone and play an important role in the effects of this hormone ,80,81. PHes5 or γ-secretase to significantly increase the expression of Atoh1 in the cochlea [As indicated, GH, via STAT5, activates the Notch signaling pathway, which has been shown to be useful in retinal neuroprotection . This ef cochlea ,86.As indicated above, GH can induce the release of other neurotrophic factors, namely IGF-I and neuropeptides, hormones, neurotrophins, growth factors, and some cytokine signaling suppressors . IGF-I iIt is interesting to note that the neurotrophic effects of GH are also mediated by the induction of classical neurotrophins such as BDNF and NT3 ,89, suppAlthough not directly related to GH, Heregulin (HRG), a member of the epidermal growth factor (EGF) family, has been reported to act as a mitogen. It stimulates the proliferation of utricular macules in mouse cultures, at least during the development of the neonatal inner ear. Its receptors are expressed in the inner ear of newborns and adults in vestibular end organs and Organ of Corti. However, the addition of HRG does not enhace cell proliferation in adults. .Throughout this review, we see that listening is a complex process that involves multiple factors that act directly or indirectly. It is clear that GH participates in auditory embryonic development and this hormone is released by a sound stimulus or a harmful event. It also plays a role in central auditory processing. Along the same lines, the absence of endogenous GH can lead to hearing loss, while its replacement can help to recover hearing loss, as it has been seen in untreated GH-deficient children. Many children in the world, including Spain, do not receive GH replacement therapy despite that they are GH-deficient. The reasons for it are diverse: Health agencies or GH Committees require two negative GH provocative tests (these are few reliable), a pituitary MRI, and a specific age. Hence, many children suffer GH-deficiency and they are not treated because they do not meet the specified requirements. This is not logical but it is the real thing. We know a number of cases.We know that multiple etiopathogenic factors cause hearing loss, including genetic and environmental disorders, which are not fully understood. Agents that promote protection from a traumatic event or degenerative process, or ideally regenerate the damage caused, have been investigated for several decades. The apparent irreversibility of hearing loss once the lesion is established forces us to search for molecules that slow down or recover the sensory cells and auditory neurons. Although studies in animal models are recent, their results and those in some GH-deficient children promise to be feasible for treatment with GH, alone or in combination with other factors. In fact, although GH might not have a direct effect, the hormone induces the expression of several factors, mainly IGF-I, which have positive actions on the recovery from hearing loss. In any case, more studies are needed to analyze in detail the effects that GH can have on a damaged cochlea.


A cross-sectional analysis was performed among 1633 asymptomatic adults who underwent colonoscopy examinations during routine health check-ups at the First Affiliated Hospital, College of Medicine, Zhejiang University, between 2015 and 2018. P for trend < 0.001). Stepwise multiple regression analysis showed that elevated hemoglobin levels independently increased the risk of colorectal polyps .  A total of 449 (27.50%) participants were diagnosed with colorectal polyps, and those with colorectal polyps had significantly higher hemoglobin levels than did those without colorectal polyps. Hemoglobin levels were positively associated with the prevalence of colorectal polyps, with rates of 16.43%, 26.20%, 32.17%, and 35.87% among participants with hemoglobin levels in the first, second, third, and fourth quartiles, respectively ( Elevated hemoglobin levels were significantly and independently associated with the prevalence and risk of colorectal polyps in asymptomatic adults. Colorectal cancer (CRC) is ranked as the second most common cancer diagnosed in women and the third most common cancer in men worldwide . The incIt has been well established that most CRCs develop from adenomatous polyps. The pathogenesis of CRC has been extensively studied, and most invasive CRCs develop from adenomas following the adenoma-carcinoma sequence . In geneA simple blood test, which is normally ordered during an annual routine health screening, can detect certain aberrations in laboratory parameters. These aberrations may be utilized to help physicians identify and stratify populations with high incidences of colorectal polyps or CRC. Kinar et al. reported that the information contained in the complete blood count report could be processed automatically by a machine learning flagging system to identify individuals with high risk of CRC . In addiIn this study, we aimed to investigate whether hemoglobin levels are associated with the prevalence and risk of colorectal polyps in average-risk asymptomatic adults.This cross-sectional study was performed among asymptomatic adults who underwent colonoscopy examinations during routine health check-ups at the First Affiliated Hospital, College of Medicine, Zhejiang University, between 2015 and 2018. Because we mainly focused on the average-risk screening population, the following participants were excluded: those with a personal history of colonic diseases , a history of colorectal surgery, or a family history of colorectal cancer or hereditary cancer syndrome. We also excluded patients who underwent colonoscopies that did not reach the cecum and those with inadequate bowel preparation . A total of 1633 participants (1123 men and 510 women) were enrolled in this study. The study protocol was approved by the hospital ethics committee.Trained physicians performed the clinical evaluations according to standardized procedures , 15. StaA fasting blood sample was obtained from each participant for analysis of blood hemoglobin level and serum biochemical variables. The blood hemoglobin level was analyzed using an automated hematology analyzer  according to the manufacturer's instructions. Serum biochemical variables were measured using a Hitachi 7600 autoanalyzer  with standard methods.Experienced endoscopists performed colonoscopies after the bowel was adequately prepared. The preparation included self-administration of 2-4 L of polyethylene glycol solution six hours before the colonoscopy. The endoscopists determined the adequacy of the bowel preparation using the Boston Bowel Preparation Scale (BBPS). A successful colonoscopy was defined as one with cecal intubation, which was confirmed by photography. The size, number, and location of polyps were recorded by the endoscopists for further analysis. Those with a successful colonoscopy and a BBPS score of six or higher were included in the final analysis.t-tests, Mann-Whitney U tests, or chi-square tests were applied to compare variables. Multiple stepwise regression analysis  was performed to explore risk factors for colorectal polyps. P values less than 0.05 (2-tailed) were considered to indicate statistical significance.Statistical analyses were performed using SPSS 18.0 software for Windows . Quantitative variables are expressed as the mean and standard deviation for normally distributed variables or median and interquartile range for nonnormally distributed variables. Student's n = 300, 66.82%) had left-sided polyps, 97 (21.60%) had right-sided polyps, and 52 (11.58%) had both-sided polyps. The size of polyps ranged from 2.0 mm to 40.0 mm with a medium (interquartile range) of 4.0 mm (2.0–6.0 mm). For 232 participants, biopsies or resections of colorectal polyps were performed; 139 (59.91%) were identified as having neoplastic polyps and 93 (40.09%) as having nonneoplastic polyps. Clinical characteristics were compared between those with and those without colorectal polyps  were diagnosed with colorectal polyps; three participants were found to have histologically confirmed colorectal carcinoma. Among those with polyps, 267 (59.47%) participants had a single polyp and 182 (40.53%) had two or more. Most of the participants (l polyps .γ-glutamyltransferase (GGT), triglycerides, uric acid, and carcinoembryonic antigen (CEA), as well as higher total and LDL cholesterol and fasting blood glucose, than those without colorectal polyps. In addition, serum HDL cholesterol levels in participants with colorectal polyps were lower than those in participants without colorectal polyps . These findings indicated that hemoglobin levels are potentially associated with colorectal polyps, and the levels may have a stronger association with neoplastic polyps than with nonneoplastic polyps.The participants with colorectal polyps were older, predominantly male, and had a greater waist circumference, a higher BMI, and a higher blood pressure than those without colorectal polyps . Those wP for trend < 0.001, To further explore the association between hemoglobin level and colorectal polyps, we divided all participants into quartiles according to their hemoglobin level: quartile 1, hemoglobin ≤ 136 g/L; quartile 2, 136 g/L < hemoglobin ≤ 150 g/L; quartile 3, 150 g/L < hemoglobin ≤ 159 g/L; and quartile 4, hemoglobin > 159 g/L. We observed the hemoglobin quartiles to be positively correlated with the prevalence of colorectal polyps. The prevalence of colorectal polyps was 16.43% among the participants with hemoglobin levels in the first quartile, and the prevalence increased to 26.20%, 32.17%, and 35.87% in the second, third, and fourth quartiles, respectively (2). Of the remaining 953 lean participants, 228 (23.92%) had colorectal polyps. Hemoglobin levels remained significantly higher in the participants with colorectal polyps than in those without colorectal polyps (148.8 (15.7) g/L vs. 142.5 (16.8) g/L, P < 0.001); thus, a positive correlation between hemoglobin levels and the prevalence of colorectal polyps was observed among lean participants. The prevalence of colorectal polyps was 15.43%, 24.24%, 30.37%, and 32.18% in quartiles 1, 2, 3, and 4, respectively (P for trend < 0.001). The results of this subgroup analysis show that the association of hemoglobin levels with colorectal polyps is independent of obesity.Obesity is a major risk factor for CRC and a potential cofactor for the association between hemoglobin level and colorectal polyps. To explore whether this association is independent of obesity, we excluded 680 participants who were overweight/obese (BMI ≥ 25 kg/mWe also conducted stepwise multiple regression analysis to investigate the association of hemoglobin levels with the risk of colorectal polyps. Seventeen variables, including age, sex, waist circumference, BMI, systolic and diastolic blood pressure, ALT level, AST level, GGT level, triglyceride level, total cholesterol, HDL cholesterol, LDL cholesterol, fasting blood sugar, serum uric acid level, CEA level, and hemoglobin level, were input into the regression equation. We found that six variables remained in the final equation, suggesting them to be independently associated with the risk of colorectal polyps . An impoIn this study, we found a significant positive association between hemoglobin levels and colorectal polyps. Hemoglobin levels were significantly higher in participants with colorectal polyps than in those without colorectal polyps. Hemoglobin levels were positively associated with the prevalence of colorectal polyps, and this association was independent of obesity. Our results also showed that elevated hemoglobin independently increased the risk of colorectal polyps. These findings may have potential clinical significance.Currently, screening for CRC is not widely available for average-risk asymptomatic adults in many rural communities and large populations. Indeed, China serves as an example of a country with a large population and a great disparity in medical resources, and national screening programs for colorectal polyps and cancer have yet to be implemented. This delay might be attributed to the large population and the strain a screening program may place on the limited medical resources of the country . TherefoScreening recommendations for classically described average-risk adults might be amended in areas with limited available resources; even the most effective and easy-to-use screening test, the fecal immunochemical test, may not be sufficient for detecting early adenomas . TherefoStudies have developed scoring systems that may help physicians easily stratify asymptomatic adults based on risk factors and direct them for colonoscopy . This stColorectal polyps are closely associated with metabolic diseases, such as metabolic syndrome and nonalcoholic fatty liver disease , 20, andAlthough the mechanism linking high hemoglobin levels and colorectal polyps is unclear, there are several probable explanations. One possible reason is that the presence of high levels of hemoglobin, an iron-containing metalloprotein, causes iron-induced oxidative stress and relative antioxidant depletion; this process has been shown to promote carcinogenesis , 23. ThiThe strength of this study lies in the large target population of asymptomatic adults and the evaluation of different serum parameters and anthropometric measurements, which were employed to assess correlations between changes in certain parameters and the presence of colorectal polyps during screening colonoscopy. The clearly observed direct proportional association between hemoglobin level and colorectal polyps is a promising avenue for further studies to analyze the existence of a causal relationship between elevated hemoglobin and the incidence of colorectal polyps. In addition, more investigations into the pathophysiological process should be conducted.Several limitations also exist in our study, including a lack of data regarding the dietary and smoking habits of the examined population. Possible confounding factors affecting hemoglobin levels, including smoking and increased red meat intake, might also be associated with the development of colorectal polyps , 25. TheIn conclusion, on the basis of this large colonoscopy-based study, we found a direct proportional association between hemoglobin level and colorectal polyps in an average-risk asymptomatic Chinese adult population. Further prospective studies should be performed to clarify these findings and identify any causal relationships between hemoglobin level and colorectal polyps.


Recent estimates reveal that there are approximately 280 000 children between the ages of birth and 14 years who are living with the human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) in South Africa. These children are living with a compromised immune system, are vulnerable to opportunistic infections and subsequent hearing loss. However, there is limited research on the nature and extent of this sensory impairment amongst school-aged children.This study aimed to determine an audiological profile of a cohort of school-aged children attending an antiretroviral (ARV) clinic, describing the occurrence of hearing loss and nature in terms of degree, type, configuration and symmetry.A non-experimental descriptive exploratory study was conducted, where 30 children aged between 6 and 12 years underwent diagnostic audiological assessments. Audiological procedures included case history, medical record review, otoscopic examination, immittance audiometry, pure-tone audiometry, speech audiometry, distortion product otoacoustic emissions (DPOAEs) and neurological auditory brainstem response (ABR) testing. The results were analysed descriptively using SPSS version 22 software.The results indicated abnormal otoscopic findings in half the participants, and consequently type C tympanograms were the most common. Of the 28 participants who could be assessed with pure-tone audiometry, 15 (54%) showed a hearing loss. A bilateral rising mild, conductive hearing loss was predominant. Thirteen (43%) of the participants could not be tested using DPOAE because of outer and middle-ear pathology. Neurological ABR testing revealed an abnormality in 18 (60%) of the participants suggesting the sensitivity of the ABR to detect subtle neurological changes.Half the children in this study showed hearing loss, which has serious implications for the holistic management of the children within the health and educational contexts. Therefore, there is a need for audiological monitoring of children with HIV and AIDS.audiological profile; HIV; AIDS; hearing loss; school children. The Joint United Nations Programme on human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) estimated that approximately 280 000 children in South Africa were infected with HIV in 2016 . The study was conducted at an ARV clinic in an urban public hospital in Durban, which is a metropolitan hub of KZN.3 and 500mm3.Thirty children were recruited for this study, with 17 (60%) males and 13 (40%) females, and an age range of 6–12 years. Participant’s grades ranged from Grade R to Grade 7. The mean age of the children was 4.3 years. There were 17 children in the foundation phase and 13 participants in the senior phase. Twenty-nine participants (97%) were on ARV treatment and one participant (3%) was ARV naive at the time of testing, as his viral load was below detectable levels. Twenty-three (79%) participants had been on ARV for longer than 5 years, and six (20%) participants have been on ARV for less than 5 years. Twenty-one (72%) of the participants were on regimen two (consisting of zidovudine [AZT] + Epivir [3TC] + Efavirenz [EFV]) whilst eight (27%) participants were on regimen one (Abacavir [ABC] + 3TC + EFV) treatment. Twenty-eight (93%) of the participants had Cluster of differentiation -4 (CD4) cell count category results reordered in their medical during the data collection phase of the study, and it ranged from 1 to 3 as reflected in The audiological evaluation followed the standard practice for children with a test battery approach and cross-check principle to ensure that results correlate  who accompanied the child to the assessment provided the case history details.A medical record form was developed for the purpose of this study. It consisted of three sections that used a checklist to capture the required information. Information on the following pertinent areas was included: CD4 cell measures within a 6-month period; viral load measures within 6 months; ARV regimen was recorded for those who had commenced ARV; other prescribed drugs for other medically related conditions; audiological interventions including audiological tests administered; and results and management strategies employed to manage the presenting audiological conditions.An otoscopic examination was conducted using a wall-mounted Welch Allyn diagnostic otoscope. The purpose was the identification of any outer ear abnormalities Gelfand, .Immittance audiometry, including tympanometry and acoustic reflex threshold testing, conducted using the Interacoustic AZ 26 middle-ear analyser with a frequency tone of 226 Hz Gelfand, .Distortion product otoacoustic emissions (DPOAEs) were conducted using the GSI Audera DPOAE.Pure-tone audiometry, including both air and bone conduction testing, was carried out using the Madsen Otometrics Itera II audiometer. Air conduction pure-tone audiometry was conducted at every octave frequency from 250 Hz to 8000 Hz, with bone conduction audiometry ranging from 250 Hz to 4000 Hz. Normal hearing was defined to be thresholds of less than 15 dB across all the frequencies Gelfand, .Speech audiometry testing included Speech Reception Thresholds (SRT) obtained through live speech testing in a soundproof booth using a digit list by Ramkisson (2002). The digit word list was used for isiZulu-speaking participants, as there was no validated word list during the time of this study. This was to address construct validity concerns. Speech Discrimination Testing (SD) to obtain Word Recognition Scores was conducted using the isiZulu discrimination word list developed by Balkisoon  for isiZAuditory Brainstem Response (ABR) testing used a Click. Click stimuli with a rarefaction polarity at an intensity of 80dBHL, duration of 0.1 ms and speed of presentation of 11.1 ms stimulation per second were used. Values of absolute latencies for waves I, III and V and interpeak latencies I–III, III–V and I–V were identified. The ABR was obtained using the GSI Audera Auditory Evoked Potentials (AEP) in a sound-treated room.Testing was conducted on the same day. Testing was conducted in a soundproof booth and sound-treated rooms to ensure reliable results Gelfand, . The parAll equipment had undergone calibration to ensure reliable results.Participants were recruited from the ARV clinic at the selected hospital with the assistance of the clinic nurse during the data collection period.Results were classified as either normal or abnormal using audiological normative data such as normal otoscopic examination findings, type A tympanogram, and ipsilateral and contralateral acoustic reflex thresholds between 70 dB and 100 dB SPL. Pure-tone audiometry across all frequencies of less than 15dB and SRT and pure-tone average agreement between 0 dB and 5 dB.The results were descriptively analysed and classified as either normal or abnormal. Data were analysed using SPSS version 22 software with the assistance of a statistician. Descriptive results were conducted using percentages, and frequency.Ethical and legal considerations were in line with the World Medical Association’s 2008 Helsinki Declaration, which included informed caregiver consent and child assent. The participants’ identities were kept confidential as they were assigned numbers for identification purposes.A pilot study was conducted on five participants to establish whether the case history questionnaire questions were clear and to identify ambiguity. The pilot study aimed to assess the rate, ease of recruiting participants and the time to conduct a full audiological test on each participant Babbie, . The recConstruct validity was accounted for by a pilot study, and the use of valid audiological and calibrated equipment. Reliability was ensured by providing short breaks between tests, and ABR result interpretation was confirmed by an expert in the field and by adhering to a data collection schedule , the Provincial KwaZulu-Natal Department of Health Research Office and the Chief Executive Officer at the study site. Written informed consent was obtained from the caregiver, and written assent was obtained from each child participant in the study  of the participants reported delays in speech-language developmental milestones, and 14 (46%) participants had other coexisting medical conditions that included tuberculosis, epilepsy and encephalopathy. Thirteen (43%) participants were suspected of hearing loss by the caregivers, and 24 (80%) participants had never had an audiological assessment although they had reported ear pathology to other health care professionals. Concerning educational history, 14 (47%) of the participants had repeated a grade whilst 15 (50%) reported not being able to cope academically in the current grade. Audiological results are presented below in terms of right and left ears.Observations revealed the presence of occlusive impacted wax (eight right and six left ears), discharge (two left and two right ears) and perforated tympanic membranes (four right and five left ears).Type A tympanogram, suggesting normal middle-ear function, was evident in the right ear of 17 participants (68%) and the left ear of 18 participants (75%), as indicated in n = 28), as two children could not be conditioned for testing. Of the 28 participants assessed, hearing loss was observed in the right ear of 15 (54%) and left ear of 13 (46%) participants. Of the 16 (57%) participants who presented with a hearing loss in either one or both ears, four (25%) presented with a unilateral hearing loss, whilst the majority 12 (75%) had bilateral hearing loss, with six (38%) having symmetrical hearing loss. Only 12 (43%) of those tested presented with hearing within normal limits. Normal hearing was classified with thresholds better than 15 dB across all the frequencies  of the participants were not assessed using DPOAE because the presence of outer- and middle-ear pathology. Majority the sample (83%) had a pass result for the right ear, with 12 (70%) having a pass in the left ear. Half of the sample 15; 50%) had abnormal absolute latency for the right ear and 10 (33%) for the left ear  and 5.; 50% hadAlmost half the children in this study had some degree of hearing loss. These findings are higher than the prevalence of 32% for the age group of 7–12 years reported by Matas et al. . Ensink In this present study, the degree of hearing loss varied across the participants, with the majority of the participants having mild hearing loss, that is, eight (29%) of right ears and 13 (46%) of left ears. These results agree with the findings of De Lange  and KhozIn this study, we found conductive hearing loss to be the predominant type of hearing loss, in line with the findings by Shapiro and Novelli , Matas eIn this study, it was observed that conductive hearing loss was the most predominant type of hearing loss, and a rising audiometric configuration was predominant, which is in line with conductive hearing loss that could be associated with otitis media  participants with a hearing loss, four (25%) participants presented with unilateral hearing loss whilst 12 (75%) participants presented with bilateral hearing loss. Caregivers suspected hearing loss in 13 (43%) participants, and 24 (80%) participants had never had an audiological assessment even though they had reported ear pathology to other health professionals, indicating a need for caregiver reports of ear-related concerns to be addressed through audiological assessments (Carney & Moeller, Furthermore, in this study, half of the participants reported that their children had repeated a grade, indicating that the presence of a hearing loss had possibly negatively affected scholastic performance. Therefore, there appears to be a possible link in children between immunocompromise and susceptibility to hearing difficulties that negatively impact on academic performance (Most & Tsach, The human immunodeficiency virus is reported to affect the inner ear, as the virus has been reported to be neurotropic and can present with neurological symptoms Lasis, . Viral aWhilst the present study findings cannot be generalised to the entire South African population because of the small sample size, it has identified that incidence of hearing loss in children with HIV and AIDS appears to be higher than observed internationally. However, this finding is interpreted with caution because of study limitations. This study supports Khoza-Shangase’s  the asse


However, some of the findings were not significant when only comparing the highest with the lowest quartile of PFASs. In conclusion, several background serum PFASs are positively correlated with hearing impairment in the United States adult population. Although studies have shown that per- and polyfluoroalkyl substances (PFAS) are potential environmental ototoxicants, epidemiologic study has been limited. I conducted a cross-sectional study to re-examine the associations between PFAS and hearing impairment. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 1999–2000, 2003-06, 2009-12, and 2015-16. Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) were measured in serum samples. Participants were divided into quartiles for each PFAS. Air conduction pure-tone audiometry was administered. Hearing impairment  was defined as a hearing threshold of more than 25 dB at 500, 1000, 2000, 4000, and 8000 Hz in the worse ear. I assessed the relation of serum PFAS with hearing impairment by the generalized linear mixed model with a logit link and binary distribution. Tests for linear trend across quartiles of serum PFAS were conducted using the median serum PFAS in each quartile as a continuous variable. After adjusting for age, sex, body mass index, education, ethnicity group, and family income, I found positive correlations between PFOA and hearing impairment at 2000 Hz ( According to the World Health Organization, an estimated 360 million people have some degree of hearing loss around the world , and expPer- and polyfluoroalkyl substances (PFAS) are listed as POPs, which are a group of manufactured chemicals that have been widely used in commercial products . One stuhttps://www.cdc.gov/nchs/nhanes/index.htm). I used data obtained from the NHANES, a nationally representative survey conducted by the US Centers for Disease Control and Prevention and the National Center for Health Statistics. NHANES includes measurements of nutritional status, chemicals and metabolites of environmental pollutants in the blood and urine, and health outcomes of the US general population, as described elsewhere [Ethical approval was not needed for this study because the data used in this study is publicly accessible , perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA), were measured in serum samples. I only included these four PFASs, because they were detectable in more than 98% of participants. Automated solid-phase extraction coupled to isotope-dilution high–performance liquid chromatography–tandem mass spectrometry was used to measure serum PFASs ,14. Standardized air conduction pure-tone audiometry was administered in a sound-isolated room by technicians trained by a certified audiologist. Air-conduction thresholds between 500 to 8000 Hz were tested for each ear using standard audiometric headphones. To ensure quality and reliability, the 1000 Hz frequency was tested twice in each ear . Particip-value less than 0.05 was considered statistically significant. All analyses were performed in SAS 9.4 software . Because serum PFASs and hearing threshold data were not a normal distribution, I categorized the data for all analyses. Participants were divided into quartiles for each PFAS. I assessed the relations of serum PFASs with hearing impairments using the logistic regression model, with PROC GLIMMIX procedure with a binomial distribution and logit link function. Tests for a linear trend across quartiles of serum PFASs were conducted using the median serum PFAS in each quartile as a continuous variable. Potential confounders were selected based on prior knowledge and their correlations with exposures and outcomes, including age, sex, body mass index, family poverty–income ratio, ethnicity, and education level. Participants with missing data were excluded. Sample weights were adjusted when performing statistical analyses . I did nThe median concentrations and range of concentrations within each quartile of PFASs is shown in p-trend < 0.01) and 1.64 , respectively. Positive associations between PFOS and hearing impairment were found at 500, 2000, and 3000 Hz. The ORs for the highest compared with the lowest quartile of PFOS were 1.41 , 1.60 , and 1.20 , respectively. Positive associations between PFNA and hearing impairment were found at 2000, 3000, 4000, and 8000 Hz. The ORs for the highest compared with the lowest quartile of PFNA were 1.68 , 1.52 , 1.53 , and 1.59 , respectively. Finally, I found positive associations between PFHxS and hearing impairment at 500, 1000, and 2000 Hz. The ORs for the highest compared with the lowest quartile of PFHxS were 1.26 , 1.44 , and 1.73 , respectively.Sensitivity analyses were performed to examine if the new included dataset NHANES 1999–2000 affected the findings. I found similar results after excluding the NHANES 1999–2000 (data not shown in table). For example, a positive association was found between PFOA and hearing impairment at 2000 Hz. The odds ratio for the highest compared with the lowest quartile of PFOA was 1.76  = 1.20–2.60). After excluding the NHANES subset 1999–2000, the odds ratio was 1.71 (95% CI = 1.13–2.59). I also conducted a sensitivity analysis to adjust all the significant results for occupational noise exposure and found that there were only slight differences in the estimates .The results from a previous study  concludeIn addition to Ding and Park’s study , only on+) homeostasis in hippocampal neurons . Loss of the sensorineural cells, including outer hair cells, has been known as a key factor contributing to hearing impairment [+ homeostasis may be a contributory factor in making outer hair cells [Although previous animal studies have reported that some environmental pollutants might be potential ototoxicants, such as dioxins, polychlorinated biphenyl, and phthalates , the stupairment . IncreasFábelová and colleagues have also postulated three possible mechanisms for the associations between environmental chemicals and hearing impairments. Firstly, the thyroid effect. Several environmental pollutants might interfere with thyroid function, which in turn can induce neurodevelopmental toxicity. PFASs have been identified as possible thyroid toxicants . Second,The strengths of this study include a fair sample size to assess the possible association between PFASs and auditory function. This study offers epidemiologic evidence that background PFAS exposure may be correlated with hearing impairment among the US adult population. The most important limitation of the study is its cross-sectional design, so the causality cannot be established. In addition, I only have a one-time assessment of the serum PFASs and pure-tone audiometry, which may introduce a misclassification of the exposures and outcomes. Finally, animal studies that can provide additional support to my findings are lacking.In conclusion, the current study found positive associations of PFOA, PFOS, PFNA, and PFHxS with hearing impairment, and the frequencies 2000 Hz and 3000 Hz were most affected. Due to the nature of the cross-sectional design, the observed findings need to be verified in more prospective cohort studies. Further animal and experimental studies are warranted to elucidate the underlying mechanism.


Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common chronic inflammatory neuropathy. CIDP is diagnosed according to the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria, which combine clinical features with the electrophysiological evidence of demyelination. However, firstly, diagnosis is challenging, as some patients e.g. with severe early axonal damage do not fulfil the criteria. Secondly, objective and reliable tools to monitor the disease course are lacking. Thirdly, about 25% of CIDP patients do not respond to evidence-based first-line therapy. Recognition of these patients is difficult and treatment beyond first-line therapy is based on observational studies and case series only. Individualized immunomodulatory treatment does not exist due to the lack of understanding of essential aspects of the underlying pathophysiology.Novel diagnostic imaging techniques and molecular approaches can help to solve these problems but do not find enough implementation. This review gives a comprehensive overview of novel diagnostic techniques and monitoring approaches for CIDP and how these can lead to individualized treatment and better understanding of pathophysiology. The chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is the most common chronic inflammatory neuropathy. Chronic and recurrent polyneuritis was first described in 1890 by Eichhorst . Around 1950 reports about steroid responsive chronic polyneuritis arose. The term ‘chronic inflammatory demyelinating polyradiculoneuropathy’ was firstly described by Dyck et al. 1982 [About 25% of CIDP patients do not respond to evidence-based first-line therapy with steroids, plasma exchange and intravenous immunoglobulins. Individualized immunomodulatory treatment does not exist due to the lack of understanding of essential aspects of the underlying pathophysiology. Definition of treatment response is often difficult, as objective and reliable tools to monitor the disease course are lacking. This review gives a comprehensive overview of diagnosis, monitoring and treatment as well as pathophysiology of CIDP.Prevalence of CIDP is estimated between 0.8 to 8.9 cases per 100,000 –5. TypicThe challenge of the correct diagnosis is depicted through the fact that more than 15 sets of diagnostic criteria were used over the last 50 years , 9. The However, there are some limitations of EFNS/PNS criteria described below. Electrophysiological criteria are complex and extensive and therefore difficult to use in daily clinical practice. The use of incomplete electrophysiological protocols can lead to misdiagnoses and delayed diagnoses . Also, cThe supportive criteria include some further difficulties as well. Breiner et al. suggested age-dependent cut-off values  for elevStudies on somatosensory evoked potentials (SEP) to detect demyelination in CIDP showed that SEP are an useful additional tool to NCS . TherefoClinical definition of atypical CIDP mentioned in EFNS/PNS criteria is vague. 2018 Doneddu et al.  defined There are multiple other chronic inflammatory neuropathies besides CIDP with distinct pathophysiology such as multifocal motor neuropathy (MMN), paraproteinemic demyelinating neuropathies (PDN) with and without anti-MAG (Myelin-associated glycoprotein) antibodies as well as nodo- and paranodopathies. Further entities like MADSAM and DADS are defined as subgroups of CIDP but also have distinct clinical characteristics, treatment response and probably distinct pathophysiology. As the terminology of CIDP subgroups therefore seems to be heterogenous, the term ‘chronic inflammatory neuropathies’ (CIN) has been used in order to summarize all these entities  Fig. 1)1). On thThe Medical Research Council (MRC) sum score, originally developed for Guillain-Barré-Syndrome (GBS) patients in the 1970ies, is part of the standard repertoire of clinical examinations used to record muscle strength .The INCAT-Overall Disability Sum Score (ODSS), first described in 2002, is well-established and validated for patients with CIDP and has developed into a standard score for CIDP . Yet, thThe INCAT sensory sumscore (ISS) is one of the few scores that sensitively records sensory symptoms in patients with GBS and CIDP .The Rasch-built Overall Disability Scale (R-ODS) is an improved disability score validated for CIDP, GBS and polyneuropathy associated with monoclonal gammopathy of unclear significance (MGUS). Indeed, it enables detection of minor changes compared to the INCAT-ODSS , 20.Classic methods for monitoring CIDP are clinical course and electrophysiology. Disability and symptom scores enable precise clinical characterization and comparison of symptoms in disease course in an objective manner.In the recent years, symptoms other than sensorimotor impairment like quality of life  were in A bedside tool to monitor grip strength is the Martin Vigorimeter which was shown to be a reliable and responsive tool in CIDP patients .It appears obvious that a worsening of the disease can be depicted by nerve conduction studies. However, nerve conduction studies cannot reproduce clinical dynamics, i.e. due to severe secondary axonal damage . StudiesMorphologic alterations of nerves can be detected by MRI. Its main advantages are high-resolution and ability to image deep and proximal tissues. However, differences in acquisition and analysis may result in significant limitations regarding validity. Short tau inversion recovery (STIR) sequences and nerve-specific T2-weighted magnetic resonance neurography (MRN) are used to quantify hypertrophy and depict increased signal intensity as signs of inflammation. Diffusion tensor imaging (DTI) enables evaluation of microstructural integrity using the parameter of fractional anisotropy, which indicates demyelination , 25. HowNerve ultrasound also enables a non-invasive view of morphology of affected peripheral nerves. The benefit of nerve ultrasound in the diagnosis of CIDP has been proven several times over the past 7 years, but it is still not established as standard diagnostic criterion. The measurement of cross-sectional area (CSA) in ultrasound correlates well to CSA detected by MRI and with the nerve T2-weighted signal intensity –28. MorpCSA enlargements can occur focally, multifocally or more generalized. Frequently, not only enlarged CSA of the whole nerve, but also individual enlarged fascicles can be observed in some CIDP patients. Multiple publications have shown the value of HRUS as an add-on tool to electrophysiological examinations for the diagnosis of CIDP and several ultrasound protocols, normal values and scores based on CSA were published to diagnose CIDP and differentiate it from GBS as well as differentiation protocols for atypical CIDP forms –35. PublThe correlation between a morphologically focal swollen nerve observed by ultrasound and a corresponding clinical and electrophysiological damage is still under discussion . In otheIn disease course, increase or decrease of CSA enlargement, i.e. measured by intra-nerve CSA variability, can provide information about disease activity and response to therapy , 41.Regarding evaluation of echogenicity, HRUS might be useful as prognostic tool, as it was shown that patients with hyperechogenic nerves have a worse prognosis than that with hypoechogenic nerves. Also, the extent of hypoechogenic fraction often occurring along with CSA enlargement correlates to disease course , 42.A limitation of nerve ultrasound is that proximal and deep nerves such as lumbosacral plexus cannot be displayed and that the quality of imaging is dependent on the expertise and experience of the examiner.Muscle ultrasound in CIDP was described to be useful to detect secondary axonal damage via reduced muscle thickness and hyperechogenic remodeling of muscles in one CIDP study . In condCorneal confocal microscopy (CCM) is a novel promising tool for evaluation of disease activity in CIDP. As a transparent medium, the cornea allows nerves of the subbasal plexus of the ophthalmic branch of the trigeminal nerve and immune cells to be visualized in vivo , 49 and The EFNS/PNS criteria were developed for use in daily clinical care as well as in clinical trials. Nevertheless, they are too complicated for routine use in non-specialized centers and misdiagnosis of CIDP is a current problem. MRI is the only imaging technique mentioned as supportive criterion in EFNS/PNS criteria that involves a high level of technical effort. In contrast, ultrasound is widely available, relatively easy to learn and efficient but is not yet included in the criteria. Nerve imaging offers the possibility of directly imaging inflammation. Nerve ultrasound should play a greater role in diagnosis of CIDP in the future as part of the diagnostic criteria, complementary to electrophysiology and MRI. As monitoring tools nerve conduction studies have shortcomings and the relevance of electromyography is not examined sufficiently. Neuromuscular ultrasound and CCM are promising approaches for disease monitoring, but the number of studies is too small to generally recommend them as standard diagnostics and monitoring. Hence, there is currently no solitary technical method that can reliably track the course of the disease.The clinical heterogeneity, different diagnostic patterns and different treatment response suggest distinct immunological pathophysiology in CIN, CIDP and subgroups. Humoral and cellular, T-cell driven, autoantibody-induced as well as complement-mediated autoimmunity occurs in all CIN and synergistically lead to damage of peripheral nerves .+ T-cells play a major role here, as they are the first cells to cross the blood-nerve barrier. The migrating T-cells secrete cytokines and chemokines and enable macrophages and antibodies to enter the peripheral nervous system. Different CD4+ T-cell subsets  were described in CIDP subgroups, which indicate differences in underlying T-cell responses between atypical and typical CIDP [+, CD8+ cells and macrophages [A crucial step is the break-down of the blood-nerve barrier, indicated by increased protein in CSF, gadolinium enhancement in of the nerve trunks, roots and plexuses in MRI studies as well as nerve swelling in ultrasound studies –54. Actical CIDP . Sural nrophages –59, but rophages , 61.The concept of classical macrophage-induced myelin destruction, reduced conduction velocities and conduction block resulting from segmental demyelination is considered typical of CIDP and related disorders , 63.Indeed, macrophages are the key player in this concept. They appear as antigen-presenting cells, create a pro-inflammatory environment, destroy the myelin through phagocytosis and directly attack the myelin , 65. ThiNerve biopsy shows features of segmental demyelination and remyelination, onion bulb formation (as a result of repeated thin-regenerating and demyelinating Schwann cell effort), nerve edema and occasionally T-cells . InflammIncreased systemic concentrations of TNFα and Interleukin-2 are markers for T-cell activation , 73. How+ T-cell-mediated attack against peripheral nerve tissue components contributes to the pathogenesis of CIDP [+ T-cells is controversial. Similar clonal expansion of CD8+ cells in sural nerve biopsies and peripheral blood was described [+ T-cells that was reduced after treatment with intravenous immunoglobulins (IVIg) [+ T-cells in CSF of CIDP patients was shown recently [+ target in CIDP. Also, in experimental autoimmune neuritis , CD8+ T-cells do not play a significant role [+ T-cells have to be developed. Also, it is currently unknown whether CD8+ T-cells mediated pathophysiology is part of classical macrophage-induced myelin destruction or a distinct entity.There is increasing evidence that MHC-I-restricted, CD8 of CIDP , 80, 81.escribed . Also, ts (IVIg) . An incrant role . HoweverThe role of B-cells is incompletely understood. In spontaneous autoimmune polyneuropathy (SAP) in non-obese diabetic mice, depletion of B-cells and plasmablasts with anti-CD19 antibodies leads to the prevention and attenuation of SAP . The rolYet, therapy response after using rituximab as a CD20-depleting antibody in CIDP patients may imply a relevant role of B-cells unless their antigen-presenting capacity toward T-lymphocytes stands in the center.The efficacy of plasma exchange  and bortIn the context of macrophage-induced demyelination an antibody-mediated pathway is assumed . Autoant+-channels and to maintain the functional structure  of the myelinated axon essential for the saltatory conduction. The paranodal disarrangement resulting from the attachment of IgG4 at paranodal junctions and the absence of macrophage-induced demyelination are characteristic pathologic features in patients who have these antibodies [In contrast, the identification of antibodies against nodal and paranodal structures brought significant progress in understanding about the role of autoantibodies in immune neuropathies –93. The tibodies , 95. Anttibodies . These mThe incidence of these paranodal antibodies is reported around 2–13% in CIDP patients , 91, 92.The data on the influence of nutrition and environmental factors in CIDP are scarce. Several studies have shown an association of diet and environmental factors like tobacco and alcohol consumption with the progression of disability in different autoimmune diseases , 99. In Capsaicin is an alkaloid contained in spicy food. It is a direct agonist of the transient receptor potential channel vanilloid subfamily member 1, that is expressed in different cell types of the nervous system as well as the immune system. This receptor and its modification by capsaicin shows beneficial immunomodulatory effects in EAN  as well In real life the influence of these factors is under discussion. In a study with 323 CIDP patients physical activity improves symptom severity, disability and quality of life, but other environmental factors as smoking, alcohol and different dietary regimes did not have an impact on the severity and health perception of CIDP .The association between genetic risk factors and CIDP is under discussion and not yet clearly described. There have been many attempts to find a human leukocyte antigen (HLA) association with CIDP with little success . Some geSerum neurofilament light chain (sNfL) levels are increased in about a third of CIDP patients and seem to reflect ongoing axonal damage in the peripheral nervous system. sNfL could therefore be a potential biomarker of disease activity however further studies are needed –109.Compound scores created from multi-dimensional CSF parameters like immune cell subtypes could become potential novel diagnostic tools as they differentiate distinct disease mechanisms in subgroups of inflammatory neuropathies .The pathophysiology of CIDP shows complex inflammatory mechanisms that result not only in demyelination but also in early axonal damage. Therefore, clinical classifications without regarding pathophysiology cannot be comprehensive. The discovery of nodo- and paranodopathies in the recent years illustrates how knowledge of distinct pathophysiology can lead to clinical differentiation of new disease entities. Therefore, biomaterial like blood, CSF and neural tissue of patients with atypical or unusual clinical characteristics needs to be available to the scientific community for further research.This further understanding of the pathophysiology is crucial to enable specific treatment options.In ICE trial, the largest and longest randomized-controlled trial comparing intravenous immunoglobulin (IVIg) treatment to placebo in 117 patients for 24 weeks, IVIg were applied with an initial dosage of 2 g/kg body weight for 2–4 days, maintained by 1 g/kg body weight for 1–2 days every 3 weeks , with a Mechanism of action of immunoglobulins is multimodal. IgG as the major component of IVIg are considered responsible for most of the immune-modulating effects , 113. AnRegarding STE treatment a Cochrane Review from 2017 revealed low evidence levels for treatment with oral or intravenous STE, mostly based on observational, but not on randomized controlled studies . NeverthFor PE, several available small trials have shown that between 33 and 66% of CIDP patients have significant short-term improvement from PE, but rapid deterioration may occur after completion of treatment . ReliablFirst-line therapies are non-specific and which of these first line therapies is suited best for which patient is still not understood. Future challenge is to differentiate further subgroups to enable more specific therapies.For CIDP patients who do not respond to first line therapies treatment is challenging due to lack of studies. About 25% of patients do not respond to any of the three first-line therapies , 120. FuObservational studies including cyclophosphamide, ciclosporin, mycophenolate, rituximab, bortezomib as proteasome antagonist and peripheral blood stem cell transplantation have been performed with positive results, but do not provide enough high-level evidence . Two comThe knowledge about distinct entities of CIN like PDN or nodo- and paranodopathies led to more specific therapies in these diseases:PDN are defined as demyelinating neuropathy, clinically often with DADS phenotype, and proof of IgM-paraproteinemia with or without anti-MAG-antibodies . PDN is There are no prospective data about treatment of nodo- and paraponopathies, but observational studies show low therapy response to IVIg , 137. A There is evidence from some studies with CIDP patients showing the effect of strength training and physiotherapy to improve muscle strength . FurtherThe first line therapy of CIDP is immunologically unspecific. In more than 20% of the patients these first-line fails. If a patient does not respond to first-line treatment reevaluation of the diagnosis is mandatory. The variable treatment response of different subtypes underlines the importance of improving our knowledge on pathophysiology. But even without specific knowledge of the pathophysiology of certain subtypes, the investigation of subgroup-specific treatment responses is needed to improve treatment response rates.CIDP and other chronic inflammatory neuropathies have been better understood in recent years. There are new molecular biological findings and innovative approaches to diagnose and monitor inflammatory neuropathies. Nevertheless, the translation of new diagnostic approaches and new subgroups into diagnostic criteria lacks. Moreover, there is a great need for further knowledge about pathophysiology and therapeutic options of ‘seronegative’ CIDP itself. Further characterization of distinct subgroups i.e. progressive or treatment refractory patients could enable targeted and more individualized therapy. Until now, treatment decisions in atypical and progressive CIDP are not evidence-based due to the lack of large controlled studies. We hope that the era of individualized treatment in CIDP will make significant progress.Previous studies, regardless of whether they investigate pathophysiology, biomarkers, genetic or environmental associations or treatment of CIN, have in common that the high number of patients to achieve significant results is difficult to obtain. A further challenge along with the emerging knowledge in clinical and molecular research is to link all these aspects. Possible reasons for delayed implementation of the different fields in CIN are the high degree of specialization of the individual international working groups and inhomogeneous structure of data.Future research about CIDP with its subtypes and pathophysiology, as well as their therapy, requires combination of high-quality prospective clinical data with the opportunity to structured collection of biomaterials from large numbers of patients. This can only be achieved through multicenter, multidimensional registers for immune-mediated neuropathies with attached biobank Fig. . A high


Gene therapy for auditory diseases is gradually maturing. Recent progress in gene therapy treatments for genetic and acquired hearing loss has demonstrated the feasibility in animal models. However, a number of hurdles, such as lack of safe viral vector with high efficiency and specificity, robust deafness large animal models, translating animal studies to clinic etc., still remain to be solved. It is necessary to overcome these challenges in order to effectively recover auditory function in human patients. Here, we review the progress made in our group, especially our efforts to make more effective and cell type-specific viral vectors for targeting cochlea cells. Hearing loss is a common neurological disorder. Both genetic causes and environmental factors, such as ototoxic chemicals, chronic ear infections, large noise, and aging, can lead to hearing loss and deafness. In China, around 2 of every 1000 children are born with a clinically significant hearing loss in one or both ears [Current therapies for hearing loss include hearing aids, middle ear prostheses/active implants to amplify the sound signal, or cochlear implants to directly stimulate spiral neurons . These aThe inner ear system contains three major types of functional cells: hair cells (HCs), supporting cells (SCs), and spiral ganglion neurons (SGNs), all of which play an important role in the process of hearing production and perception. There are two types of sensory HCs in the cochlea: the outer HCs (OHCs) and the inner HCs (IHCs). OHCs amplify sound signals, while IHCs convert the mechanical information carried by sound waves into electrical signals that are transmitted to the neurons .Many genes in both HCs and SCs play essential roles in the development or maintenance of cochlea and thus are involved in regulating the cochlea function and hearing. Here we provide a very brief information in this area. For more details, please refer other elegant review articles –6.Transmembrane channel-like 1 (TMC1) is a pore-forming component of channels that participate in mechanoelectrical transduction of sound in cochlear and vestibular HCs . OtoferlBesides hair-cell gene mutations, SC gene mutations have also been linked to deafness. SCs are located at the bottom of the inner and OHCs, anchoring the sensory epithelium to the basilar membrane, thus playing a mechanical role in protecting and maintaining the surrounding environment for HCs. Some key deafness genes mainly express and have functions in SCs, such as GJB2, which affects the SC’s gap junction and is the most common hereditary deafness gene , 15, 16.SGNs, located in a bony channel  that spirals around axis of the cochlea (modiolus), are primary neurons of the auditory system. The HCs release glutamate neurotransmitters upon sound stimulation to bind NMDAR2 and mGluRIs on the SGN membrane to produce excitatory electricals. SGNs transmit these electrical signals to the auditory cortex through the eighth cranial nerve, enabling us to hear outside sound. Thus, SGNs, as the bridge between HCs and brain, are required for normal hearing. Unfortunately, noise exposure, ototoxic drugs, and genetic factors can cause the irreversible SGN damage or death, and thus the communication between HCs and brain is disturbed, leading to sensorineural hearing loss .In recent years, gene therapy has emerged as an important method to treat inherited diseases Table . AlthougAkil et al. loaded the VGLUT3 gene with AAV1 vectors to VGLUT3 knockout neonatal mice that displayed deafness by round window membrane (RWM) injection . VGLUT3 Despite of many exciting advances in gene therapy for deafness in animal models, there is still a long way to go before it can be applied to deafness in humans. There are currently more than 20 clinical trials for hearing loss therapies in the United States with six potential therapeutic molecules. Intriguingly, there is one clinical trial involving gene therapy for auditory diseases . MoreoveIt is feasible to systematically characterize the specificity of different AAVs to transduce the different cell types in the cochlea. An elegant study showed that AAVs specifically transduced different types of retina in both mice and nonhuman primate under the control of different gene modulator components . In ChinTo achieve this, we employed a strategy similar to a previous study  and aim Atoh1 can lead to transdifferentiation of SC into HCs [Atoh1-NLS-mNeonGreen (AAV-ie-Atoh1) to deliver mouse Atoh1 into the cochlea. New hair-cell-like cells were generated in the AAV-ie-Atoh1 group as unambiguously demonstrated by the immunofluorescence labeling and SEM experiments  element. These studies are intended to obtain synthetic promoters of genes specifically expressed in inner ear cells, and prepare for the next step of in vivo screening.The promoter sequences of specific expression genes are chosen using four different methods Fig. . At the By using these strategies to choose the promotor sequence of specific genes in cochlea cells, we are able to generate the highly transducing AAV variants in HCs, SCs, or SGNs (data not shown). It is a substantial amount of work to generate these AAV variants and screen for their transducing efficiency and specificity. We will continue these efforts to optimize AAV variants, which can transduce the cochlea cells in adult mice and other large animal models, such as pigs and nonhuman primates.SOX10 (R109W) in pigs by N-ethyl-N-nitrosourea mutagenesis causes inner ear malfunctions and hearing loss [While most work related to inner ear gene therapy is conducted in rodents, larger animals, such as pigs or nonhuman primates, which have ears that are closer to those of humans, are better animal models for evaluating the efficiency/specificity and toxicity of AAV variants. Thus, these large animal models may extend translational proof-of-principle studies. China has established the largest pool of pig models and a large amount of mutations have been generated , 53. Inting loss , and migIt is an exciting time for inner ear gene therapy. With the advent of new AAV variants displaying high efficiency and specificity in transducing cochlea cells and with the establishment of large animal models, such as pigs and nonhuman primates, we would expect the rapid translation from basic research to clinical trials is feasible. There are more than 100 different genes causing genetic hearing loss, yet the mechanisms underlying hearing dysfunction by distinct gene mutations are different and need to be fully investigated before developing the gene therapy strategy for each hearing deaf gene. Despite many challenges, there are reasons for optimism as new AAV variants, which specifically and efficiently target different cochlea cells, are developed and more collaborative projects, from both basic scientists and clinical doctors, are conducted to develop feasible gene therapy strategies for hearing loss.


Specific multimorbidity combinations, in particular those including arthritis, stroke, or cognitive impairment have been associated with high burden of ADL/IADL disability. However, the biologic underpinnings of these associations are still unclear. We used data from the Health & Retirement Study  and negative binomial regression models to evaluate if metabolic and inflammatory biomarkers  mediate the association between specific multimorbidity combinations  and ADL/IADL disability (at subsequent wave in 2012-2014). Results were adjusted for sociodemographic characteristics, body-mass index, number of coexisting chronic diseases, and baseline ADL/IADL score. HbA1c  and CRP , but not HDL, were positively associated with the number of coexisting diseases. After adjustment for coexisting diseases, higher HbA1c was associated with greater ADL/IADL limitations for multimorbidity combinations including arthritis  and stroke , but not for combinations centered around other diseases, while CRP was no longer significantly associated with ADL/IADL limitations for any of the multimorbidity combinations. Models accounting for HbA1c and CRP, respectively, showed that only combinations including cognitive impairment had greater ADL/IADL limitations  compared to combinations without cognitive impairment. Insulin resistance and inflammation are strongly associated with the burden of multimorbidity; this strong association, rather than the biomarkers per se, appears to explain the greater ADL/IADL burden observed with all disease-specific multimorbidity combinations, except cognitive impairment.