Although the administration of fluid is the first treatment considered in almost all cases of circulatory failure, this therapeutic option poses two essential problems: the increase in cardiac output induced by a bolus of fluid is inconstant, and the deleterious effects of fluid overload are now clearly demonstrated. This is why many tests and indices have been developed to detect preload dependence and predict fluid responsiveness. In this review, we take stock of the data published in the field over the past three years. Regarding the passive leg raising test, we detail the different stroke volume surrogates that have recently been described to measure its effects using minimally invasive and easily accessible methods. We review the limits of the test, especially in patients with intra-abdominal hypertension. Regarding the end-expiratory occlusion test, we also present recent investigations that have sought to measure its effects without an invasive measurement of cardiac output. Although the limits of interpretation of the respiratory variation of pulse pressure and of the diameter of the vena cava during mechanical ventilation are now well known, several recent studies have shown how changes in pulse pressure variation itself during other tests reflect simultaneous changes in cardiac output, allowing these tests to be carried out without its direct measurement. This is particularly the case during the tidal volume challenge, a relatively recent test whose reliability is increasingly well established. The mini-fluid challenge has the advantage of being easy to perform, but it requires direct measurement of cardiac output, like the classic fluid challenge. Initially described with echocardiography, recent studies have investigated other means of judging its effects. We highlight the problem of their precision, which is necessary to evidence small changes in cardiac output. Finally, we point out other tests that have appeared more recently, such as the Trendelenburg manoeuvre, a potentially interesting alternative for patients in the prone position. Fluids, administered to patients with shock and hypotension in the operating room or intensive care unit (ICU), are drugs. On the one hand, their effect is inconstant, due to inter-individual variability in the relationship between cardiac output and preload . When flTherefore, it is logical to condition the infusion of fluid boluses on the prediction of their effectiveness. The main goal of this prediction is to avoid administering ineffective fluid, which would only have deleterious effects without generating any benefit. For this purpose, several tests and indices have been developed.The aim of this review is to provide an up-to-date summary of knowledge regarding these tests and indices, emphasizing the literature published in the last three years. What do recent studies add regarding their reliability? How should they be performed in practice, and how should their effects be assessed? What is new regarding their conditions of use? What new tests have been developed? These are the questions we will try to answer.Transferring a patient from a semi-recumbent position to a position where the trunk is horizontal and the lower limbs are elevated at 30–45° mobilizes blood from the splanchnic territory and the lower limbs and significantly increases mean systemic pressure, the upstream pressure of systemic venous return  is that The reliability of the PLR test for detecting preload responsiveness is well established, after the publication of numerous studies  and someHowever, it has long been clear that unfortunately the haemodynamic effects of PLR cannot be measured on simple arterial pressure measured invasively  and, a fWhat haemodynamic monitoring techniques can be used for this purpose? Since the effects of PLR are sometimes limited in time , cardiac output must be estimated in real time Fig. . Pulse wIn recent years, many more studies have been devoted to the description of alternative methods to estimate the haemodynamic effects of PLR, less invasive than pulse contour analysis and simpler to perform than echocardiography.This is the case for bioreactance , at least in its latest version, in which the duration over which cardiac output values are averaged and the frequency at which their refreshed display are compatible with the duration of the PLR effects . HoweverAnother non-invasive and easy-to-use solution may come from the plethysmography signal. Its amplitude is estimated by the perfusion index, the ratio between its pulsatile portion, which is displayed on bedside screens, and the non-pulsatile portion. This index is determined by vasomotor tone, which decreases its amplitude, and stroke volume, which increases it . Then, eDuring PLR, two studies by our group showed that the increase in perfusion index, which is automatically measured by some monitors, followed changes in cardiac output during a PLR test and that these changes detected a preload responsive state , 28. An Another attractive way to assess PLR effects might be to assess changes not in a surrogate of cardiac output but in the respiratory variation of arterial pulse pressure (PPV) or stroke volume (SVV) in mechanically ventilated patients. Indeed, it has recently been reported that the decrease in PPV induced by a PLR test, reflecting the decrease in preload responsiveness induced by the preload challenge, detects preload responsiveness , 30 Tab. LikewisPreload responsiveness could even be detected by the effects of the PLR test on capillary refill time , althougThe use of carotid or femoral arterial flow during the PLR test is more doubtful. Indeed, published studies are highly contradictory, some showing that these arterial flows follow the changes induced by the PLR test , while oPLR testing is contraindicated in patients with intracranial hypertension, and it is difficult to perform during surgery. Venous compression stockings likely result in false negatives by reducing the mobilized blood volume . HoweverMore recently, a study suggested that intra-abdominal hypertension, which would reduce the splanchnic blood volume mobilized during PLR, or even interrupt the inferior vena cava flow by a waterfall phenomenon, would generate some false negatives . The resAs PPV and SVV, the end-expiratory occlusion (EEO) test detects preload dependence by taking advantage of cardiopulmonary interactions . In mechThe duration of the EEO must be longer than 12 s , to alloOn the other hand, the advantage of the test is that it is easy to perform Fig. . It is vThe effects of the EEO test are fleeting, as they begin to wear off as soon as mechanical ventilation resumes. In addition, they are relatively small, so, therefore, is the diagnostic threshold. Thus, measuring the effects of the EEO test requires an estimate of cardiac output that is both in real time and precise  Fig. 2)2).For this purpose, the drawback of arterial pulse pressure is that its changes during a 15-s EEO cannot be seen simply on bedside monitors . The pulAs with the PLR test, several recent studies have looked at the method that can be used to detect the effects of the EEO test. The drawback of cardiac ultrasound for measuring the effects of the test is that its precision is relatively low. As underlined before, the smallest detectable change in stroke volume  in the LVOT) is 10%, below the diagnostic threshold for the EEO test . TherefoWhen using oesophageal Doppler, which has the same precision issues as cardiac ultrasound, the combination of EEO and end-inspiratory occlusion can also be used . It was In one study, changes in the plethysmographic perfusion index were shown to closely follow changes in the cardiac index during EEO, as it did during PLR . A diagnFinally, tools that track changes in cardiac output or stroke volume during the EEO test must be able to capture relatively brief effects. Thus, the commercial version of the bioreactance system, which averages cardiac output over 24 s, cannot track the effects of the test. However, a modified version bioreactance system that reduces the cardiac output averaging time to 8 s was recently shown to be quite appropriate . Such reOne study reported that the EEO test was reliable at 8 mL/kg Vt but not at a 6 mL/kg Vt . HoweverTwo studies also suggested that the EEO test was unreliable in the prone position , 57. In Finally, a study recently suggested that the EEO test loses sensitivity during laparoscopic surgery . It is pPPV, which is an easy way to quantify the decrease in systolic arterial pressure induced by the inspiratory decrease in cardiac preload under mechanical ventilation (delta down), is the preload responsiveness index that has the highest level of evidence . HoweverThe question of false positives of PPV induced by right heart failure remains unresolved. The reality of this theoretical limitation is not certain, as it was evaluated by only one human study with many limitations . A recenThis test makes it possible to overcome the unreliability of PPV in the event of low Vt ventilation. When Vt is at 6 mL/kg of predicted body weight, the test consists of increasing it transiently from 6 to 8 mL/kg and measuring the induced changes in PPV . If the The Vt challenge has been validated by far fewer studies than the PLR test, for example, although its reliability has been confirmed in a recent meta-analysis . MoreoveRecent publications suggest the interest in the Vt challenge in the operating room context , 67, wheThe test can be used in patients with some spontaneous breathing under mechanical ventilation . This haVariation in the diameter of the vena cava has long been proposed for the detection of preload dependence in mechanically ventilated patients . The advThe distensibility of the vena cava unfortunately shares with PPV and SVV the fact that it cannot be used when Vt is low, as has been recently shown , when luThe reliability of variations in the diameter of the vena cava has been reported to be quite low in several studies and meta-analyses published in recent years –71. A laThis may have a physiological explanation. Variations of the vena cava do not depend only on the state of preload responsiveness, but on other factors as well. For the inferior vena cava, while it is true that its intramural pressure, the central venous pressure, varies more in amplitude in the event of preload responsiveness , which tHowever, in septic non-intubated patients, a recent study suggested that preload responsiveness was detected by changes in the diameter of the inferior vena cava induced by a standardized respiratory manoeuvre . NeverthIn addition to intra-abdominal hypertension, vena cava distensibility shares with PPV some conditions in which it is less reliable: spontaneous breathing, low tidal volume and lung compliance Table . ConsideThe most obvious way to detect preload responsiveness is to infuse a bolus of fluid and measure its effects on cardiac output. The fluid challenge has for years been proposed to guide fluid therapy .However, it is easy to understand that a "classic" fluid challenge, with the infusion of 200–500 mL of fluid, is not a "challenge", but the treatment itself. If there is no preload responsiveness, which occurs in half of the cases, it is not possible to withdraw the fluid administered in excess. The classic fluid challenge inevitably leads to fluid overload. In addition, the fact that cardiac output increases following the infusion of 200–500 mL of fluid does not necessarily imply that this will be the case for the next bolus. The volume is indeed large enough to convert preload-dependent ventricles into independent ones.Therefore, the idea of administering only a “mini-fluid challenge”, performed with a quite small volume of fluid to assess preload responsiveness is interesting . It consAfter relatively small studies, two recent meta-analyses confirmed the reliability of the mini-fluid challenge , 54. ThiThe mini-fluid challenge requires direct estimation of cardiac output or stroke volume, that is, it cannot be done by just measuring arterial pressure changes Fig. . During In addition, the diagnostic threshold for the mini-fluid challenge is relatively small (5% on average Table  45]). T). T45]).In contrast, the precision of echocardiography in measuring the LVOT VTI may not be good enough, as its least significant change is 12% . So, if The decrease in PPV and SVV during a mini-fluid challenge, which would indicate a decrease in the degree of preload responsiveness, might be used as a surrogate for an increase in cardiac output to assess the effects of the test. Two small studies recently showed that the decrease in PPV and SVV during a 100 mL mini-fluid challenge predicted the response to volume expansion with acceptable reliability , 64  predictfor 25 s , 88 and for 25 s . To our 2O and by measuring the slope of the drop in systolic blood pressure induced . No. No56]. First of all, it must be remembered that no test or diagnostic index is perfect, for preload responsiveness tests or for any other tests. The further the result from the diagnostic threshold, the more likely the diagnosis. This is what some have conceptualized with the concept of a "grey zone", in which a greater or lesser number of patients are located depending on the test considered.Additionally, it should be kept in mind that while patients are classified as "preload responders" and "preload non-responders" in studies, to determine sensitivity and specificity, the degree of preload dependence is a physiologically continuous variable. Thus, if the result of a test or index takes an intermediate value, close to the diagnostic threshold provided by the studies, this perhaps corresponds to an intermediate degree of preload dependence, not to a weakness of the diagnostic tool.There are cases where the positive response of cardiac output to a bolus of fluid is certain, and in which the patient’s ventricles must work on the steep part of the Frank-Starling curve. This is certain if cardiac preload is very low. In clinical practice, this corresponds to obvious hypovolaemia, the initial phase of septic shock before any volume expansion, because of the strong relative hypovolaemia, haemorrhage… In these cases, preload responsiveness is present for sure, and testing it may only delay urgent fluid administration.In contrast, in all other cases, fluid infusion increases cardiac output in only half of the cases, if fluid responsiveness is not tested. In this context, a dynamic measurement of preload responsiveness is recommended, as during sepsis for example .First, the assessment of fluid responsiveness cannot be dissociated from the clinical context, and no fluid should be administered if it is not obvious that cardiac output needs to be increased. There is no need to test for preload responsiveness if there is no acute circulatory failure as suggested by the absence of clinical signs of organ hypoperfusion . In such a case, a positive index or test of preload responsiveness must not lead to volume expansion. Preload responsiveness is a physiological state, and it makes no sense to want to fix it systematically.Second, the need for infusing fluid boluses must be tested along with the risk of administering fluids. Even if preload responsiveness is present, if the risk exceeds the benefit, fluid should not be infused. In assessing risk, many indices may be considered, as a high central venous pressure or pulmonary artery occlusion pressure, a high level of extravascular lung water and severely impaired blood oxygenation, or an elevated intra-abdominal pressure, for instance . AlternaThe real need in assessing fluid responsiveness is that fluid should not be given in the case of fluid unresponsiveness, as if it is ineffective fluid will only contribute to fluid overload and its deleterious effects. It is now well established that an increase in fluid balance during an ICU stay  or afterFrom this perspective, testing preload responsiveness can also serve to guide fluid removal at the therapeutic de-escalation phase in shock patients. Indeed, in the absence of preload responsiveness, it is likely that the fluid can be withdrawn in a safe manner, without the risk of lowering cardiac output and causing hypotension . In addiIf the detection of a preload responsive state is to precede the administration of fluid, it is important to verify, if a bolus of fluid has been administered, that it has indeed increased cardiac output . First, none of the diagnostic methods are perfect, and false positives or false negatives are always possible. Then, if a significant response of cardiac output to fluid administration is noted, it is possible that a preload responsiveness state persists, so that the question of renewing a fluid bolus may arise.Finally, the ultimate goal of volume expansion is to correct tissue hypoxia. Due to the non-linear relationship between oxygen consumption and oxygen delivery in some cases, the fluid-induced increase in cardiac output is not always accompanied by improved tissue oxygenation . It is tRecent studies and meta-analyses have addressed the issue of whether a strategy guided by the assessment of preload responsiveness improves patient outcome, in the ICU or in the operating theatre.It seems that these two settings should be considered differently. In the operating theatre, there are quite a few studies comparing an interventional fluid strategy guided by preload responsiveness assessment with a standard strategy. They were of relatively small size, but their meta-analyses suggested a benefit of the interventional fluid strategy regarding different outcomes. In a 2017 meta-analysis including 13 trials (1652 patients), 12 of which were performed in post-surgical patients, a fluid strategy based on a fluid responsiveness assessment significantly decreased mortality and ICU length of stay . This meIn addition, in the peri-operative period, several studies have examined the effect on outcome of using a goal-directed therapy, which included, in addition to other therapeutic interventions, a fluid strategy guided by assessing preload responsiveness. Several of these studies and their meta-analyses  have shoIn non-surgical ICU patients, far fewer studies are available. Three randomized control trials only have been published in English in peer-reviewed journals –106 Tab. They weFinally, in a multicentre observational study in Argentina including 787 septic shock patients, the use of various indices and tests assessing fluid responsiveness was associated with a better outcome in logistic regression analysis . NeverthAt the very least, it can be said that a strategy using the assessment of preload responsiveness in septic shock patients is certainly not deleterious and that it does not excessively delay therapeutic management.However, even if further studies on larger numbers of patients were carried out, it is not at all certain that they could show improved survival. Indeed, a decrease in mortality may not be the ideal outcome for demonstrating the benefit of a treatment in critically ill patients . In patiFinally, should we wait for the results of survival studies to implement methods assessing preload responsiveness in clinical practice? Since these methods are harmless, as they often use cardiac output monitoring which is recommended anyway in shock patients  and patiThe most recent studies in the prediction of fluid responsiveness have primarily described means of measuring the effects of well-established preload responsiveness tests, such as the PLR test, the EEO test and the mini-fluid challenge. In particular, methods replacing invasive and costly measurements of cardiac output have been described. In addition, the limits of these tests have been better defined. Some recent studies have also developed and validated new tests, the best validated of which is the Vt challenge, which has the advantage of being assessed with no direct estimation of cardiac output. There is now some evidence that in the peri-operative period the use of a therapeutic strategy adapting fluid resuscitation to the detection of preload responsiveness reduces post-operative complications. In non-surgical critically ill patients, such as septic shock patients, few outcome studies have been performed, suggesting a reduction in the amount of administered fluid.


Organ function is known to decline with age. Optimizing cardiac, pulmonary and renal function in older adults has led to significant improvements in perioperative care. However, when substantial blood loss and fluid shifts occur, perioperative outcomes still remains poor, especially in older adults. We suspect that this could be due to age-related changes in endothelial function—an organ controlling the transport of fluid and solutes. The capillary filtration coefficient (CFC) is an important determinant of fluid transport. The CFC can be measured in vivo, which provides a tool to estimate endothelial barrier function. We have previously shown that the CFC increases when giving a fluid bolus resulting in increased vascular and extravascular volume expansion, in young adults. This study aimed to compare the physiologic determinants of fluid distribution in young versus older adults so that clinicians can best optimize perioperative fluid therapy.Ten healthy young volunteers (ages 21–35) and nine healthy older volunteers (ages 60–75) received a 10 mL/kg fluid bolus over the course of twenty minutes. Hemodynamics, systolic and diastolic heart function, fluid volumetrics and microcirculatory determinants were measured before, during, and after the fluid bolus.P < 0.01). Basal CFC and plasma oncotic pressure were lower in the older versus younger adults. Further, CFC did not increase in older adults following the fluid bolus, whereas it did in younger adults (p < 0.05). Cumulative urinary output, while lower in older adults, was not significantly different (p = 0.059). Mean arterial pressure and systemic vascular resistance were elevated in the older versus younger adults (p < 0.05).Diastolic function was reduced in older versus younger adults before and after fluid bolus (Older adults show a less reactive CFC to a fluid bolus, which could reduce blood to tissue transport of fluid. Diastolic dysfunction likely contributes to fluid maldistribution in older adults. Question: Evaluate the physiologic response to fluid bolus in older adults.Findings: Capillary filtration coefficient did not increase in older adults.Meaning: Older adults appear to retain more fluid compared to younger adults, which is associated with diastolic dysfunction.Major surgery poses the risk of a patient losing large quantities of blood and fluid. Excessive fluid administration in critically ill patients can lead to cardiac complications , has been described in chronic disease, such as diabetes  at Galveston reviewed and approved the protocol and experimental procedures prior to the start of this study (Protocol number 09–215). Inclusion criteria included, men or non-pregnant women in good health, between 21 to 35 years of age and 60 to 75 years of age. Written informed consent was obtained from all subjects and all subjects scored ≥ 26 Mini-Mental State Exam. Subjects were excluded if they had a history of cardiovascular disease determined by history of hypertension, peripheral vascular diseases, heart attack or stroke and previous echocardiographic evidence of diastolic dysfunction (E/e’ > 10) or systolic dysfunction (EF% < 50%). Subjects were also excluded when presenting with cardiac conduction defects, bleeding disorders, anemia, diabetes, neurologic, renal, endocrine or lung diseases (e.g. asthma or chronic obstructive pulmonary disease), known allergic reactions to indocyanine green dye, shellfish or iodine, history of more than 20 pack-years tobacco smoking, alcohol or drug abuse, positive tests for hepatitis or HIV, presence of acute illness or medically unstable chronic illness, or if they were on hormone replacement therapy.Covidien PLC, Dublin, Ireland) and blood pressure cuff were placed and connected to a clinical monitor . Two venous catheters  were placed in each arm  for drug and fluid administration, respectively. An arterial catheter  was placed in the radial artery under local anesthesia  and connected to a pressure monitoring kit  with a 0.9% NaCl  pressure bag.This was a prospective, paired, study performed in nineteen healthy volunteers at the General Clinical Research center (GCRC), UTMB. Volunteers were instructed not to eat or drink after midnight, the day before the study. On the day of the study, the volunteers reported to the GCRC. Vital signs (heart rate (HR), non-invasive blood pressure measurement and of peripheral oxygen saturation by plethysmography) and weight were obtained. The subjects were positioned supine in a hospital bed. A three lead ECG, pulse oximeter , after monitors and catheters were placed. Initial plasma volume was determined by indocyanine green.T minus 10 (T-10), Measurements were obtained prior to fluid infusion.Baxter Healthcare Corp., Deerfield, IL, USA)T zero (T0), start of the 10 mL/kg 0.9% saline fluid bolus (T twenty (T20), end of fluid bolus.T sixty (T60), 60 min after start of fluid bolus.T one hundred twenty (T120), end of study.Each subject underwent identical fluid protocols. The specific time points and interventions were Fig. :T minus Details of the specific measurements and timing are described in detail below.General Electric Medical Systems Inc., Milwaukee, WI, USA). Left ventricle (LV) area and length were interrogated in parasternal long axis position. The Modified Simpson’s rule was applied for calculation of end-diastolic (EDV), end-systolic volume (ESV). Stroke volume (SV) was determined from the calculation of EDV – ESV and the ejection fraction (EF%) was determined by SV/EDV. Cardiac output (CO) was calculated from SV • HR. Systemic vascular resistance (SVR) was calculated from CO/MAP. Echocardiographic parameters were measured at T-30 min, T0, T20, T60 and T120. The transthoracic echocardiographies were performed by the senior author, who is a highly experienced anesthesiologist and intensive care physician.Measurements for HR and mean arterial blood pressure (MAP) were recorded at T-30, T0, T5, T10, T15, T20, T30, T60, T90 and T120. Echocardiographic (ventricular volume and function) parameters were measured by transthoracic echocardiography using a 3.5 MHz transducer and ultrasound machine . Measurements were obtained at T0, T20, T60, T90 and T120. Initial plasma volume (PV) was determined with the spectrophotometric detection of indocyanine green  using optical densitometry bound to plasma proteins  was measured at 840 nm using spectrophotometry . The change in PV (ΔPV) is directly proportional to the initial plasma volume + changes in hematocrit   ) using mass balance after T0. Cumulative urinary output (UO) was measured via an ultrasound bladder scanner  ) divided by the changes in venous pressure (∆Pv) as: CFC = ∆Jv/∆Pv. Three separate inflation pressures , each sustained for three minutes, were performed before fluid bolus, during and immediately at end of fluid bolus, one hour after fluid bolus and study end . The collection of these measurements provided insight into derangements in the Starling Equation, as described below.The capillary filtration coefficient (CFC) was determined in vivo using venous congestion plethysmography (VCP). In brief, step-wise increases in venous pressure were performed by applying a pressurized cuff on the thigh and a mercury-silastic strain gauge transducer on the calf  Fig. a (GambleSA) Fig. . The chaThe amount of pressure applied to the cuff, limb girth % and time (min) were digitally sampled and stored using Powerlab . The CFC was determined from an offline analysis using the shallow slope from the change of % limb girth and time Fig. b. VCP mepl) was estimated using a derived formula from these constituents as previously described in detail . The plasma colloid osmotic pressure  would be reduced and less responsive in older subjects. Therefore, sample size determination was based on the primary outcome, basal CFC. Data obtained in previous young healthy volunteers showed that CFC was 2.6 ± 1.0 (mean ± SD). We surmised that older adults would result in a 50% lower CFC, based on lower transcapillary fluid reabsorption rates reported in older adults. A sample size of 10 per group would have 80% power to detect an effect size of 1.000 using a two-group t-test with a 0.050 two-sided significance level. Thirteen subjects in each group were recruited to accommodate for attrition.Students t-test and two-way analysis of variance were used for data analysis. Bonferroni post hoc comparison was used when applicable. Statistical analyses were performed using Prism 4 for Mac . Data are expressed as mean ± S.E.M. Statistical significance was accepted when p ≤ 0.05.Baseline plasma volume was not significantly lower in the older population . SVR was elevated in the older population (p < 0.05), although both populations had a similar SVR directly after the fluid bolus. Also, both groups showed a similar drop immediately at the end of the fluid bolus administration.HR and CO were similar during all time points throughout the study. CO reached its highest peak at the end of the fluid bolus. MAP was elevated in the older population before, during, and after the fluid bolus , and continued to rise during and after the fluid bolus  was not significantly different between the groups Fig. a. The fllus Fig. c. This slus Fig. d.Fig. 4Ep = 0.059, Fig. in over time) was similar in both populations  was lower in the older population compared to the younger population, though this result was not statistically significant (p < 0.05). After rising to a level that was significantly different (T60 from T20), CFC levels in the younger population fell slightly towards baseline values during/after the fluid bolus (T120) All timepoints were significantly different from baseline in the younger population. The fluid bolus resulted in no significant change from baseline in the older population. COPpl significantly fell in both groups after the fluid bolus. The nadir occurred at 20 min. There was partial restoration in COPpl to basal levels by study end . This study evaluated physiologic differences in older adults that govern the distribution of a fluid bolus.Cardiovascular and blood volume differences, based on age during non-dynamic conditions, have been reported. Specifically, Best et al., showed that older subjects have a lower blood volume and stroke volume, and higher systemic vascular resistance (SVR)  and increase the net fluid movement (Jv). This relationship can be understood through the Starling equation, which describes the forces that determine fluid movement across capillaries:A key finding in this study was the reactivity in the CFC between older and younger adults before and after the fluid bolus. Interestingly, while older adults had a lower CFC, vascular and extra-vascular volume expansion after the fluid bolus was not increased compared to younger adults. This is somewhat paradoxical in that reduced CFC should expand plasma volume due to reduced blood-to-tissue transport; on the other hand, reduced diastolic function increases the filling pressure of the heart. Increased filling pressure could increase the capillary pressure  is reduced in aging and could contribute to volume trapping in older adults  responses likely contribute to the physiologic responses after a fluid challenge. Specifically, changes in splanchnic circulation and response to hypo- and hypervolemia must be recognized. The splanchnic circulation is a low resistant high capacity system that receives approximately 25% of the cardiac output and therefore serves as an important fluid and blood reservoir . Also, the volume challenge or fluid bolus (10 mL/kg) was modest in this study, mostly due to safety reasons. Previously, our group showed more pronounced changes in CFC, in younger adults, with a 25 mL/kg fluid bolus  and invasive techniques that were not practical for healthy volunteer studies. Finally, we did not measure total body water or extracellular water and other hormones, which could have impacted retention and fluid distribution.We focused on the CFC and COPThis study showed that the CFC in older versus younger adults was less reactive to an intravenous fluid bolus. Older adults tend to retain more fluid than younger adults, but not in the plasma. Although a lower CFC by itself would decrease transcapillary fluid etravasation during the fluid bolus, impaired diastolic function likely offsets this interaction. This mechanism may explain lower basal plasma volume yet similar plasma volume expansion in the two age groups. This may also contribute to fluid trapping, such as the lower urinary output seen in the older adults. Additionally, the association a larger fluid bolus and other factors need further investigation.


Fluid analysis is an initial approach for determining the underlying causes of body cavity effusions. Modified transudate is commonly diagnosed in pleural effusion in cats, however, it provides limited diagnostic information. Aims of this study were to investigate common etiologies causing different pleural fluid types and to evaluate the usefulness of lactate dehydrogenase (LDH) for differentiating the etiology in modified transudates in cats. Pleural effusion samples from 122 cats were analyzed and classified into three types: transudate, modified transudate, and exudate. Causes of pleural effusion were classified into four conditions: cardiac disease, neoplasia, feline infectious peritonitis (FIP), and pyothorax. The relationship of underlying etiology and fluid types was described. The LDH levels in pleural fluid and plasma were compared between the causes in the samples classified as modified transudate. The fluid analysis of pleural effusion showed that modified transudate was the most common fluid type (44.2%). Neoplasia was predominantly diagnosed (38.5%) as the etiology of pleural effusion. There was no significant correlation between pleural fluid and plasma LDH level in any type of pleural fluid, suggesting that pleural fluid LDH does not appear to be affected by plasma LDH. The occurrence of modified transudate was not associated to its etiologies, however, the LDH level in modified transudates showed significant differences between etiologic groups. The LDH level in modified transudate was excellent in separating cardiac from non-cardiac diseases with a cut-off value of <535 U/L and separating FIP from non-FIP diseases with a cut-off value of >641 U/L. Based on the current findings, pleural fluid LDH can be a useful adjunctive marker for differentiating some causes of modified transudate pleural effusion and should be added in the routine diagnostic work-up of feline patients with pleural effusions. Pleural effusion is a common cause of respiratory distress that brings cats to emergency hospitalization. Body fluid analysis helps clinicians to identify underlying mechanisms of fluid accumulation and provide an initial list of differential diagnosis . Light'sIn veterinary medicine, body cavity effusion has been classified into transudate, modified transudate, and exudate based on the TP concentration and total number of nucleated cell count (TNCC) –6. WhileLactate dehydrogenase is a cytoplasmic enzyme that catalyzes the pyruvate conversion to lactate during anaerobic glycolysis. Cell types with different energy requirement contain different LDH level which is minimally distributed in the blood. Increased LDH level in the extracellular spaces such as serum, saliva, cerebrospinal fluid, and body cavity effusion is related to its leakage from damaged cells and can be indicative of a pathologic process –14. AnalThere have been limited studies on the prevalence of underlying diseases which are causing distinct types of pleural effusion. Determining the etiology is important for proper treatment and a systematic approach is necessary because the differential diagnosis for pleural effusion is diverse. As LDH plays a key role in cellular energy metabolism, the increase of its concentration in a confined space such as the thoracic cavity possibly indicates local tissue pathology in different diseases. The aims of this study were to investigate common etiologies causing different pleural fluid types and to evaluate the usefulness of LDH to differentiate the etiology in modified transudates.N = 122). The pleural fluid samples obtained by ultrasound-guided thoracocentesis were collected in EDTA or plain tubes. If available, plasma samples were collected from the cats on the same day of thoracocentesis as a part of the clinical work-up. Routine body fluid analysis including cytology, TNCC, and TP concentration were performed by a veterinary clinical pathologist within 6 h after the thoracocentesis. The fluid supernatant and plasma biochemistry including triglyceride (in cases suspected of chylothorax), LDH activity, and TP concentration were determined using biochemistry analyzer . According to veterinary classification of body cavity fluid, the pleural effusions were divided into three types  for the first time  antigen and feline immunodeficiency virus (FIV) antibody were tested using lateral flow test . Detection of feline coronavirus (FCoV) by RT-PCR in pleural fluids were performed at the Veterinary Diagnostic Laboratory, VET CU using the protocol described elsewhere . ClonaliCardiac disease was diagnosed based on clinical history with evidence of cardiomyopathy by echocardiography, thoracic radiography, and/or increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration using lateral flow test .Neoplastic effusion was diagnosed by a suggestive radiography of the mass in the thoracic cavity and histopathology or cytology of neoplastic cells in the effusion. Diagnosis of malignant epithelial tumor was given to the cases when neoplastic epithelial cells were found with or without mild neutrophilic inflammation. Diagnosis of lymphoma was given to the cases with inconclusive lymphoproliferative lesion when clonality testing was suggestive.Feline infectious peritonitis was diagnosed by supportive signalment, clinical signs, presence of protein-rich pleural fluid, and positive results of RT-PCR testing for FCoV in the effusions.Pyothorax was diagnosed when intracytoplasmic bacteria were observed in cytology or a bacterial culture from pleural fluid sample was suggestive.Chylothorax was diagnosed based on physical characteristics such as milky appearance, predominant presence of small lymphocytes and lipid droplets on cytology, and the triglyceride concentration >100 mg/dl .post-hoc test. Receiver operating characteristic (ROC) curve analysis was used to plot sensitivity and one-specificity for distinguishing the underlying causes of modified transudate and the optimal cut-off values were selected based on Youden's index . Descriptive analysis and contingency table were used to summarize the relationship between pleural fluid type and underlying etiology. The normality of the data was evaluated by Kolmogorov-Smirnov test. Log transformation of LDH activity was used. The correlation of log (LDH) and TP between pleural fluid and plasma was evaluated using Pearson's correlation coefficient. Data from modified transudate were selected to compare between log (LDH) and etiologies using one-way ANOVA and Tukey's 's index , 20. TheN = 108) as neoplasia, cardiac disease, FIP, and pyothorax were displayed with the frequency of the pleural fluid type in a contingency table , followed by exudate  and transudate . Out of 122 cats with pleural effusion, neoplasia represented the largest group of the patients , followed by cardiac diseases , FIP , pyothorax , and chylothorax . Four cats were diagnosed with more than one etiology (two cats had cardiac disease with neoplasia and two cats had cardiac disease with pyothorax) and eight cats had unknown etiology due to insufficient clinical information. Cytology of pleural fluid diagnosed with pyothorax, FIP, and neoplasia was shown in cy table . Transudr = 0.298; P = 0.05) in all fluid types. Significant correlation of TP in pleural fluid and plasma was observed , particularly in the modified transudate fluid .The Pearson's correlation illustrated scattered plots of TP concentration and LDH level in pleural fluid and plasma . There wP < 0.0001; neoplasia, P = 0.003) and cats with cardiac disease had significantly lower pleural fluid LDH . There was no difference in plasma LDH between groups (P = 0.766)  .Receiver operating characteristic analysis was performed in cats with modified transudate pleural effusion for determination of LDH values as predictors of underlying etiology. Pleural fluid LDH in modified transudates distinctly categorized cardiac from non-cardiac diseases (area under the curve (AUC) = 0.873) and FIP from non-FIP diseases (AUC = 0.849). The cut-off values of pleural fluid LDH to distinguish cardiac disease and FIP were <535 and >641 U/L, respectively. Pleural fluid to plasma LDH ratio had less separability for cardiac disease (AUC = 0.857) and FIP (AUC = 0.831). The cut-off value of <0.75 and >1.95 of pleural fluid to plasma LDH ratio could specifically identify cardiac disease and FIP, respectively .c-myc gene, a cellular proto-oncogene, is frequently disrupted by the FeLV genome insertion resulting in oncogene overexpression and uncontrolled proliferation of the affected cells  in accordance with the faculty regulations. Written informed consent was obtained from the owners for the participation of their animals in this study.HM conducted data acquisition, contributed to data analysis, and drafted the manuscript. VH contributed to data analysis and provided statistical guidance during the drafting of the manuscript. JS assisted in data acquisition. ARu advised on data analysis and provided scientific guidance. ARa established the concept of the project, contributed to data analysis, and drafted the manuscript. All authors contributed to the article and approved the submitted version.HM received master's degree support from the Chulalongkorn University Graduate Scholarship Program for ASEAN and Non-ASEAN Countries and Chulalongkorn University Graduate School Thesis Grant (3/2021). This study was supported by Veterinary Science Research Fund, Chulalongkorn University (RG2/2563).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Atelerix albiventris) presented with an intraoral, soft tissue mass overlying the left mandible. A computed tomography scan and subsequent fine needle aspirate suggested a malignant spindle cell tumour. The tumour was excised with a partial hemimandibulectomy. Histopathology demonstrated an incompletely excised spindle cell sarcoma. The hedgehog underwent adjuvant therapy consisting of intravenous carboplatin and oral lomustine, followed by palliative radiation therapy once tumour recurrence was noted on follow‐up surveillance. Radiation therapy was initially successful in decreasing tumour size, but the hedgehog re‐presented a month later acutely non‐ambulatory paraparetic with a distal right antebrachial mass. Diagnostics including radiographs and fine needle aspirate were consistent with metastatic neoplasia and humane euthanasia was elected.A 2.5‐year‐old male African hedgehog  presented with an oral mass which, following a CT scan and cytology confirmed a soft tissue sarcoma. The oral soft tissue sarcoma was excised with hemimandibulectomy and treated with follow‐up chemoradiotherapy.A 2.5‐year‐old male African hedgehog ( The mass was suddenly noticed by the owners who reported no prior medical history. Additional information regarding the origin of the hedgehog, housing, diet and husbandry is relevant to provide full history, although it was not ascertained in this case. The hedgehog was manually restrained and anaesthetized with sevoflurane gas administered via face mask. Physical exam revealed a 1.5 cm × 1.0 cm intraoral soft tissue mass overlying the left mandible.A 2.5‐year‐old intact, 290‐g male African Hedgehog  and midazolam . Anaesthesia was mask induced and maintained with isoflurane gas (0.5%) and oxygen (1 L/min). CT scan showed a large soft tissue mass invading the left hemimandible causing underlying cortical disruption Figure . The hedThe hedgehog returned 6 days later for tumour excision and partial left hemimandibulectomy. The hedgehog was premedicated and anaesthetized following previous anaesthetic protocols. An intravenous catheter was placed in the right cephalic vein. The hedgehog was given warm lactated Ringer's solution  intraoperatively. The gingival mucosa was elevated caudal to the left canine and the soft tissues were elevated surrounding the mass. The left mandible was resected caudal to the left canine and cranial to the left ramus. Subcutaneous tissues and the skin were closed with 5‐0 Vicryl in a continuous suture pattern and interrupted suture pattern, respectively. All tissues were submitted for histopathology. Post‐operatively, the hedgehog was administered hydromorphone , meloxicam , and warm lactated Ringer's solution . The hedgehog was discharged the following day with meloxicam , tramadol , and Oxbow Carnivore Care with Harrison's Recovery Formula .Histopathology of the excised tissue revealed an infiltrative, unencapsulated neoplasm with extensive areas of necrosis, haemorrhage and inflammation. Tumour cells were elongated with indistinct cytoplasmic borders, small amounts of fibrillar eosinophilic cytoplasm and an elongated cell nucleus with a stippled chromatin pattern and indistinct nucleoli. The mitotic index was 4–8 per high‐power field. These findings were consistent with an incompletely excised spindle cell sarcoma. The owners were warned of a high reoccurrence risk. Despite the paucity of effective chemotherapy protocols in hedgehogs with spindle cell sarcoma, carboplatin therapy  was recommended.Over the course of 9 weeks, the hedgehog received three doses of carboplatin, which were well‐tolerated, and the animal gained 36 g. However, 2 months after beginning carboplatin therapy a firm swelling was noted overlying the ventral aspect of the remaining left mandible, consistent with tumour regrowth. At this time, the chemotherapeutic agent was switched to lomustine . Over the course of 8 weeks, the hedgehog received 5 doses of lomustine which decreased tumour size.Approximately 6 months after beginning chemotherapy the tumour increased in size and was noted to invade the oral cavity, partially obstructing the pharynx. The hedgehog also developed a deep corneal ulcer of the left eye. To assess tumour invasiveness a CT scan was performed which showed a progressively larger mass with destruction of the underlying mandibular bone. The mass extended caudoventrally beyond the caudal aspect of the larynx, occluding the airway and causing left exophthalmos, nasolacrimal duct obstruction and exposure keratitis Figure . Given tThe hedgehog was administered a total dose of 8 Gy (400 cGy per treatment) in four fractions over 4 weeks. To facilitate therapy, the hedgehog was anaesthetized following previous anaesthetic protocols and intubated with a 14 g catheter. Devitalized corneal epithelium of the left eye was debrided under anaesthesia and hairs ventral to the left eyelid were pulled as needed. At home, the hedgehog was given oflaxacin , genteal eye lubricating gel  and meloxicam . Over the course of a month the keratitis improved, the corneal ulcer healed and the tumour decreased in size.Despite initial improvement, about a month later the hedgehog became acutely non‐ambulatory paraparetic. Upon re‐evaluation, the tumour was larger and displacing the tongue laterally, there was a firm nodule on the lateral aspect of the right carpus, and the urinary bladder was large and firm. Under general anaesthesia blood and urine was collected, fine needle aspirate of the right carpal nodule was obtained and full body and right forelimb radiographs were performed. Radiographs showed variably sized lytic lesions within the proximal humeral metaphyses and humeral heads, body of T5, right ilium, left pubis and ribs Figure . A polyo2Neoplasia is very common in hedgehogs, with retrospective studies reporting prevalence between 29% and 53% in study populations   is commonly used for tumour management in canines and felines (Rejec et al., CR in this report was challenging, primarily due to small patient size and lack of established protocols in hedgehogs. Vascular access was lost during a carboplatin treatment, forcing some of the dose extravascular. Additionally, vascular access could not be obtained during one visit, so the hedgehog needed to return the following week which prolonged therapy.Detecting evidence of metastatic disease can also be difficult in hedgehogs as metastatic pulmonary nodules can be missed radiographically due to artifact of summating quills. It is important for the clinician to understand that a physical examination under general anaesthesia with complete blood count, serum biochemistry, urinalysis, thoracic radiographs, abdominal ultrasound and fine needle aspirate and cytology are necessary for complete neoplasia workup (Heatley et al., This report illustrates that partial hemimandibulectomy and CR for a spindle cell sarcoma could improve long‐term prognosis in a hedgehog. Both treatment modalities were well‐tolerated, but more studies are needed to establish efficacy and specific protocols for the hedgehog patient. This study also highlights the reality that more complete local tumour control, by achieving clear surgical margins initially, will afford better long‐term outcome. If complete tumour excision is not possible and positive margins are found, adjuvant therapy consisting of immediate RT may result in better local tumour control and decrease risk of metastasis. Furthermore, following RT, re‐biopsy of the area could have been performed to assess response to RT, much like is done with human patients (American Society for Therapeutic Radiology and Oncology Consensus Panel, The authors confirm that the ethical policies of the journal, as noted on the journal's author guideline page, have been adhered to. No ethical approval was required as this is a case report with no original research data.Andrew Lacqua – Conceptualization, Investigation, Project administration, Resources, Supervision, Validation, Visualization, Writing‐original draft, Writing‐review & editingRebecca Dreizen – Conceptualization, Investigation, Project administration, Resources, Validation, Visualization, Writing‐original draft, Writing‐review & editingPeter Helmer – Conceptualization, Supervision, Visualization, Writing‐review & editinghttps://publons.com/publon/10.1002/vms3.738.The peer review history for this article is available at


Twitter presence in academia has been linked to greaterresearch impact which influences career progression. The purpose of this studywas to analyse Twitter activity of the radiotherapy community around ESTROcongresses with a focus on gender-related and geographictrends.interactions, around the ESTRO congresses held in2012–2021 were collected. Twitter activity was analysed temporally and, for theperiod 2016–2021, the geographical span of the ESTRO Twitter network wasstudied. Tweets and Twitter users collated during the 10 years analysed wereranked based on number of ‘likes’, ‘re-tweets’ and followers, considered asindicators of leadership/influence. Gender representation was assessed for thetop-end percentiles.Tweets, re-tweets and replies, here designated asTwitter activity around ESTRO congresses was multipliedby 60 in 6 years growing from 150 interactions in 2012 to a peak of 9097 in2018. In 2020, during the SARS-CoV-2 pandemic, activity dropped by 60 % to reach2945 interactions and recovered to half the pre-pandemic level in 2021. Europe,North America and Oceania were strongly connected and remained the maincontributors. While overall, 58 % of accounts were owned by men, this proportionincreased towards top liked/re-tweeted tweets and most-followed profiles toreach up to 84 % in the top-percentiles.During the SARS-CoV-2 pandemic, Twitter activity aroundESTRO congresses substantially decreased. Men were over-represented on theplatform and in most popular tweets and influential accounts. Given theincreasing importance of social media presence in academia the gender-basedbiases observed may help in understanding the gender gap in careerprogression. The momentum generated incited institutions andindividuals to reflect on these questions, including in the academic community.A growing body of evidence now indicates that gender-based biases influence,sometimes unconsciously, the healthcare work environment and the inter-personalrelationships within it In recent decades, the field of radiotherapy has undergoneprofound evolutions largely driven by the digital transformation of societyDuring international radiotherapy congresses community membersconnect with one another and disseminate their research, which may result inincreased activity on Twitter. One such event is the annual congress of theEuropean Society for Radiotherapy and Oncology (ESTRO). In 2020 the COVID-19pandemic compelled the ESTRO society to cancel the plenary setting of thecongress and to hold it in virtual format. This may have driven moreradiotherapy professionals to social media platforms to compensate for the lackof in-person interactions. The change to virtual platforms has had profoundimplications on the demographics of conference attendance across differentfields, in particular increased attendance by women The purpose of this study was to analyse the activity on Twitteraround ESTRO congresses to reveal salient characteristics of the ESTRO communityinteracting on Twitter, with a focus on gender-related and geographictrends.22.1† and replies to tweets related to ESTRO wereretrieved for the period covering the past ten ESTRO congresses (from 2012to 2021). For the remainder of this article, the terminteraction refers to interpersonalcommunications  as well as original tweets.Posts on Twitter (tweets), re-tweets1The Twitter application programming interface was queried toretrieve activity dealing with ESTRO that originated around each of theannual congress ±5 days. For example, the keywords used for the year 2021were #ESTRO, #ESTRO2021 and #ESTRO40. The full list of keywords is detailed,in addition to congresses’ locations and dates, in The temporal evolution of the number of collected Twitterinteractions was analysed. For the period 2016 to 2021 where the totalnumber of communications grew above 1000, the connections that took placebetween persons re-tweeting or replying to an original tweet, and the authorof the tweet in question were mapped, using the users’ locations, to analysethe evolution of the geographical network of collaborators.2.2Communications were studied on a sub-sample of the dataexcluding Twitter accounts that represented associations, corporations orindividuals using the #ESTRO for opportunistic purposes . This excluded 1463 of the 4258accounts from further analysis. The pronouns listed in a user’s profiledescription were used to categorise gender into two categories  with a caveat that this oversimplified description does not includenon-binary, gender-fluid, or gender-neutral individuals. For individuals whodid not have pronouns listed, information provided on a users’ profile was used to assign gender. If gender could notbe assigned from this information the individual was classified asunidentified.Liking or re-tweeting someone else’s tweet gives moreaudience and credibility to the message and the originator. These actionscan also be interpreted, to some level, as expressing support, endorsementor even a sign of deference. Therefore, the number of ‘likes’, re-tweets andfollowers were used as quantitative indicators of popularity,leadership/authority and influence.To determine whether tweets authored by individuals of aspecific gender trigger more such actions from the community, all tweetsretrieved were pooled and ranked by number of 1) likes and 2) re-tweets,ordered in quartiles and percentiles. The proportion of male and femaleauthors was evaluated for the fourth quartile, the 90th, 95th and 99thpercentiles, comprising the top liked/retweeted tweets. The female/maleratio (F/M) in each group was then compared to the one of the whole sample.This analysis was complemented by an individual-specific approach in whichTwitter users that interacted more than once were ranked based on thecumulated number of 1) likes, 2) re-tweets and 3) replies to tweets theyauthored during the past ten congresses and 4) followers. Then, similarly tothe approach described above, the F/M ratio was determined for the subgroupsof Twitter profiles and compared to the one of the sample. To test forstatistical significance of gender imbalance in the percentiles of interest,comparison with gender ratio of the whole sample analysed was performedusing Fisher’s exact test.2.3Gender representation as well as the average number ofinteractions on Twitter over the ten years studied were assessed for Twitterusers who were grouped by professional qualifications. The profiles wereclassified, when relevant, using the following categories: PhD students,post-doctoral researchers, PhD holders, associate/assistant professors,professors, radiotherapists/radiographers/radiation therapists (RTT),physicists/clinical scientists or clinicians. This categorisation wasperformed based on the presence of specific keywords shown in The data extraction and subsequent analysis were performedusing Matlab software (v.R2021b).33.1Twitter activity related to ESTRO peaked during congressesas shown in Evolution over time of thegeographical distribution of the network of collaboratorsthat communicated via re-tweets or replies to tweets aroundESTRO congresses, displayed in videoformat.The evolution over time of the geographicaldistribution of the network of collaborators exchanging on Twitter aroundESTRO congresses is displayed in the animated map in 3.2The 2795 accounts selected were categorised as: 1526 (55 %)male, 1100 (39 %) female and 169 (6 %) profiles with unidentified gender.Excluding those unidentified, gender representation was 58 % male and 42 %female users. This proportion was relatively stable over time, withmale/female proportions oscillating as shown in As illustrated in In the analysis of the impact of tweets B, those 3.3Of the 2626 selected accounts with allocated gender, aprofessional qualification  was identified in 1162 ofthem. These were composed in majority (71 %) by clinicians, with 822profiles . Physici4The analysis of 31,483 interactions covering the last ten ESTROcongresses has shown that Twitter activity dropped substantially during theSARS-CoV-2 outbreak, with a 60 % decrease to 2945 interactions in 2020. Mostintercommunications originated from Europe, North America, and Oceania with76 %, 15 % and 6 % respectively. Also, men appear to be over-represented by 10 %on the platform as, 58 % of the profiles with an identified gender were men and42 % women while the F/M ratio of European ESTRO members is 52 %/48 %. Inaddition, men were increasingly over-represented towards top liked/re-tweetedtweets and most followed profiles and by up to 26 % in the top 1 %.Twitter activity during and around ESTRO congresses considerablyincreased over the past ten years, going from ∼ 150 interactions in 2012 to apeak at 9097 in 2018. ESTRO annual congresses are regularly held in April orMay. However, this pattern was disrupted by the SARS-CoV-2 outbreak as, in 2020,the congress was postponed twice to finally take place fully online in December.In 2021 the congress was held in a hybrid format in August. The virtual congressformat eases economic and travel-related obstacles, which was found in aprevious study to possibly result in increased participation from women,scientists living with a disability, early-career researchers and researchersfrom countries with limited resources The world regions that mostly contributed to communications onTwitter were Europe, North America and Oceania, which are areas that comprisemost of the economically-advanced countries, according to the InternationalMonetary Fund definition The gender imbalances observed in this study, are fullymeaningful when put into perspective considering the gender ratios in the field.The term over-representation was used when, for a sub-group studied,representatives of a specific gender were present in a proportion higher thanthat of the whole sample. The analysis of the number of likes, re-tweets andreplies per tweet, which can be considered as indicators of popularity,leadership and influence, revealed that men were increasingly over-representedtowards top liked/re-tweeted tweets. This over-representation reached a maximumof 25 % for the 1 % top-re-tweeted tweets. Conversely, women wereover-represented by up to 6 % in the last quartile of Twitter profiles thatcumulated the highest number of likes, re-tweets and replies during the periodstudied. However women over-representation did not follow a monotonic trend,thus, for higher percentiles, a progressive return to gender balance wasobserved A. It isThe professional qualifications of Twitter users analysed inthis study seem to be relatively representative of the ones of ESTRO membersThe list of keywords used to categorise Twitter users based ontheir professional qualifications resulted from an iterative filtering processin which Twitter account information was systematically reviewed to ensure thatno significant account types were left out from the analysis. The imbalance inkeyword numbers for different categories is therefore reflecting the imbalancein professional qualifications claimed by the users. In line with this approach,a category focussing on radiobiologist profiles was considered but had to beomitted due to the insufficient number of corresponding profiles tostatistically determine gender balance estimates.To make this analysis possible, three gender categories wereused but for the most part, our study focussed on a binary approach to genderwhich does not reflect the complexity of gender identification. In addition,Twitter does not provide self-reported gender information and gender wastherefore allocated based on preferred pronouns when available or based on theauthors’ perceptions otherwise.Social media presence is becoming increasingly important inacademia. It has been linked to greater research impact In conclusion, Twitter activity around ESTRO congresses wasmultiplied by 60 in 6 years growing from 150 interactions in 2012 to more than9000 in 2018. During the SARS-CoV-2 outbreak, activity dropped by 60 % in 2020and then recovered to only half the pre-pandemic level the next year. Europe,North America and Oceania were strongly connected and remained the maincontributors. Men were over-represented overall on the platform as well as inmost popular tweets and influential accounts. Because of the increasingimportance of social media presence in academia, the gender-based biasesobserved in this study, may help in understanding the gender gap in careerprogression.5The data analysed in this study are public information whichwere retrieved from the Twitter Application Programming Interface (API). Thesystematic access and analysis of this data were subject to permission that wasgranted to the authors by Twitter. At this occasion, the authors have committedto solely publish data resulting from statistical analysis hence avoidingpublication of identifiable information from Twitter users.The authors declare that they have no known competing financialinterests or personal relationships that could have appeared to influence the workreported in this paper.


High-grade gliomas, in particularly diffuse midline glioma, H3K27-altered in children and glioblastoma in adults, are the most lethal brain tumour with a dismal prognosis. Developments in modern medicine are constantly being applied in the search for a cure, although finding the right strategy remains elusive. Circumventing the blood–brain barrier is one of the biggest challenges when it comes to treating brain tumours. The cat and mouse game of finding the Trojan horse to traverse this barrier and deliver therapeutics to the brain has been a long and hard-fought struggle. Research is ongoing to find new and feasible ways to reach specific targets in the brain, with a special focus on inoperable or recurring brain tumours. Many options and combinations of options have been tested to date and continue to be so in the search to find the most effective and least toxic treatment paradigm. Although improvements are often small and slow, some of these strategies have already shown promise, shining a light of hope that finding the cure is feasible. In this review, we discuss recent findings that elucidate promising but atypical strategies for targeting gliomas and the implications that this work has on developing new treatment regimens. High-grade gliomas are the most lethal primary malignancy in the central nervous system (CNS), both in children and adults, due to their localisation and invasive growth. Gliomas represent 80% of all malignant primary brain tumours and are responsible for most deaths from these tumours . Glioma The term glioma was coined over 150 years ago, and since that time a variety of gliomas have subsequently been described. Bassoe and Apfelbach first described diffuse intrinsic pontine glioma (DIPG) in two cases, a girl, and a boy, both aged 6 years old, in 1925, detailing its infiltrative and destructive nature . Two casTo date, treatment for high-grade gliomas remains inadequate, with 95% of patients succumbing to their disease within 5 years after diagnosis . StandarConsidering the overall poor outcome from current treatment options for both operable and inoperable glioma, the need for improved targeted therapies becomes evident in overcoming this highly lethal disease in children and in adults. In recent years, numerous review papers have been written outlining the conventional strategies in treating gliomas as well as those that have shown early in vitro or pre-clinical promise. Current strategies in overcoming the BBB for drug delivery, such as focused ultrasound and convection-enhanced delivery, as well as approaches involving nanoscale applications including liposomes, micelles, hydrogels and radiosensitisers, have previously been described in detail –11. ThisAlthough studies on both pediatric and adult gliomas are reviewed, most studies cited here are based on in vitro and pre-clinical adult glioma models, due to the lower availability of research material and a lack of literature in the pediatric field. In addition, enrolment of children in clinical trials is difficult, due to both low disease prevalence and parental reluctance, as well as lack of funding . NeverthA major challenge in glioma therapy is the selective delivery of therapeutics to tumour cells behind the BBB, while limiting damage to other tissues. Although cell-penetrating peptides (CPPs) have been studied for nearly half a century, only the last decade or so has investigated their potential as a promising new strategy for targeted glioma treatment. CPPs are short peptides that can be coupled to various carriers for the selective delivery of drugs, imaging agents, nanoparticles, oligonucleotides and liposomes . CPPs caPre-clinical research has already shown promising results for CPP-mediated drug delivery in various cancer models, including glioma. A study in which the glioma homing CPP interleukin-13 peptide was anchored onto nanoparticles showed specific targeting and uptake by U87 MG cells, as well as enhanced penetration of particles into tumours both in vitro and in vivo . When loNanocarriers conjugating CPPs and polyethylene glycol (PEG)-lipid conjugates have also been designed to enhance the targetability of tumours through prolonged circulation time and exposure at the tumour site . The higAlthough several brain-penetrating CPPs such as HIV-1 Tat, penetratin and SynB1 have been established and are being investigated to date, their number is still limited. A recent study showed that conjugating an 11 amino acid long CPP derived from the cell membrane entry signal of HIV-1 Tat to a chemically modified peptide mimicking H3K36me2 was able to inhibit the proliferation of DIPG cells harbouring a H3K27M mutation in vitro, while wild type cells were not affected . As the Another emerging strategy to enhance the delivery of therapeutics across the BBB is magnetic drug delivery, in which external magnetic fields guide magnetic drug carriers towards the tumour site and increase local therapeutic efficacy. Superparamagnetic iron oxide nanoparticles (SPIONs), consisting of magnetite (Fe3O4) or maghemite (γ-Fe2O3), are promising magnetic carriers for this purpose, being biocompatible, biodegradable and integrated into the body’s iron cycle after degradation . SurfacePaclitaxel (PTX)-loaded SPIONs were recently established to assess the anti-tumour effects in human U251 GBM cells . CompareTemozolomide (TMZ)-loaded SPIONs conjugated to the glioma-targeting ligand folic acid (FA) have also been established for dual targeting of rat brain glioma . In vitrDoxorubicin (DOX)-loaded SPIONs (DOX-SPIONs) have also been developed to study magnetic drug delivery to glioma cells both in vitro and in vivo , 29. TheThe potential of magnetic nanoparticles to target GBM cells that have spread within cerebrospinal fluid has also been explored . MagnetiAn alternative application of SPIONs is their utilisation as an imaging tool for delineation of resectable glioma in the operating room to guide surgeons. The use of fluorescent SPIONs for intraoperative imaging of GBM by targeting tumour-associated macrophages (TAMs) has already been investigated . The fluMetal-free carbon nitride quantum dots (CDs) are nanoparticles with potential for biomedical applications as they harbour favourable properties such as good biocompatibility, photostability and tunable photoluminescence, as well as nontoxicity. Furthermore, being easy to produce and liquid dispersible makes them ideal candidates for application in bioimaging, drug delivery and theranostics . The strUsing a simple one-step method, Ruan and colleagues prepared fluorescent carbon dots with demonstrated serum stability and low cytotoxicity, which could also be taken up by C6 glioma cells in vitro in a time- and concentration-dependent manner. In vivo, these carbon dots accumulated and distributed throughout the glioma in orthotopic C6 glioma-bearing mice, suggesting their potential in non-invasive glioma imaging applications . Zheng aConjugates of CDs with the chemotherapeutic gemcitabine were investigated in their ability to selectively target and kill pediatric GBM cells in vitro . AlthougThe synergistic effects of a triple conjugate targeting system, consisting of CDs conjugated to transferrin and the chemotherapeutic compounds epiburicin and TMZ, on pediatric and adult glioma cells, have also been investigated in vitro . The effRecently, a novel strategy to selectively image and deliver drugs to glioma using CDs structurally modified to mimic large amino acids that could bind to the large neutral amino acid transporter 1, which is expressed in most tumours, was examined . As the A recent in vitro study combined the use of transferrin decorated magnetic nanoparticles with a different type of non-toxic quantum dots, namely InP/ZnS quantum dots, to investigate dual targeting and imaging of glioma . The resNeoantigens, or tumour-specific mutations, are more frequently being investigated as targets for glioma treatment utilising the immune response against the tumour. Advancements in cancer immunogenomics have allowed for the identification of targetable neoantigens, offering promise for the effectiveness of immunotherapy and priming it against tumours of the brain .In comparison to adult brain cancer, pediatric brain cancers have less mutational load and corresponding neoantigens, and a tumour microenvironment with a smaller number of immune cell infiltrates. Consequently, immunotherapies developed for adult brain tumours are usually not as effective when applied to pediatric brain tumours, resulting in relatively fewer trials on immunotherapy for childhood glioma . Fortuna+ CD8+ T cell clone was established through stimulation with a synthetic peptide containing the H3.3K27M mutation. These T cells effectively killed HLA-A*02.01+H3.3K27M+ glioma cells in an antigen- and HLA-specific manner in vitro. Transfer of these T cells also efficiently inhibited the progression of glioma xenografts in mice.A relatively recent neoantigen, lysine (K) to methionine (M) substitution at position 27 of histone 3 variant 3 (H3.3K27M), for glioma T cell therapy has been investigated rigorously since being identified . The ma+ and H3.3K27M+ status, were enrolled in a DIPG  or non-pontine DMG  arm of the trial. The vaccine was administered together with an immunostimulant every 3 weeks for 8 cycles, followed by once every 6 weeks. Overall, the vaccine was well-tolerated and patients with H3.3K27M-specific CD8+ immunological responses showed prolonged overall survival compared to non-responders . Although no significant differences in overall survival between the two strata were observed, these results warrant further studies targeting the H3.3K27M epitope.Recently, the safety and efficacy of a H3.3K27M-targeted peptide vaccine were assessed in the Pacific Pediatric Neuro-Oncology Consortium . Newly d+ glioma cell cultures [+ diffuse gliomas . Results from the first four patients enrolled in the study were recently published, and show that the treatment is well-tolerated and that 3 of 4 patients derived clinical and radiographic benefits following intravenous administration of GD2-CAR-T cells. A second dose of GD2-CAR-T cells via intracerebroventricular administration provided additional radiographic/clinical benefits in three of three patients treated. Additionally, on-target, off-tumour toxicity was not observed in any of the patients. Although it is early in the trial, with only a few patients tested, the current results of this therapeutic approach are promising and encouraging for patients of glioma [The disialoganglioside GD2 is another tumour-associated antigen that has gained interest in cancer immunotherapeutics due to its limited expression in normal human tissues  and unifcultures  and in gcultures . A firstf glioma .50 values in the low nanomolar range. Given the positive results observed so far, multivalent vector proteins could be further used in pre-clinical models in the foreseeable future. Although immunotherapeutic intervention should be regarded with caution, the development of immunotherapies focusing on recruitment, activation and retention for pediatric glioma is warranted to harness the potential of this strategy in treating brain tumours in children.Tumour-associated antigens or neoantigens enable selective targeting (e.g. through immunotherapy) of the glioma microenvironment. However, such targets may be expressed on some tumour cells but not on others, which can result in some cells escaping immunotherapy. To limit tumour immune evasion, patients should receive immunotherapy that targets multiple neoantigens. For example, a recent study developed a novel multivalent vector protein, QUAD 3.0, which concurrently targets four GBM associated Eph receptors . This apRecent developments in targeted therapy and immunotherapy have raised hopes for the treatment of glioma. However, some challenges concerning these approaches remain to be addressed, including toxicity to healthy tissues, the inability to treat deep tumour tissue and the possibility of inducing drug resistance in tumour cells , 51.Although not a novel concept, live tumour-targeting bacteria offer a unique opportunity to meet these challenges. Compared to other strategies, tumour-targeting bacteria have multiple capabilities for suppressing cancer . These bSalmonella typhimurium (S. typhimurium) A1-R strain can suppress and eliminate human glioma in an orthotopic mouse model [typhimurium A1R is auxotrophic (leu ⁄arg-dependent) but receives sufficient nutrition from tumour tissue and does not continuously infect normal tissue. In one study, glioma-bearing mice were treated with S. typhimurium by intravenous or intracranial injection once a week for three weeks and observed via intravital microscopy. Intracranially administered bacteria were shown to inhibit brain tumour growth at 7.6-fold higher compared to untreated mice and significantly improved survival, with two of ten mice appearing to have their tumours eliminated. The same study showed that intravenous administration of bacteria was not effective. Another study used S. typhimurium A1-R to assess its anti-tumour efficacy through intravenous or intrathecal injection in orthotopic mouse models of spinal cord glioma [It has previously been demonstrated that the attenuated tumour-targeting and highly mobile se model . S. typd glioma . IntrathSalmonella species pluralis are facultative anaerobes which can survive in oxygenated environments [Typhimurium strain displaying an integrin-binding Arg–Gly–Asp(RGD) peptide on its outer membrane to enhance specific targeting was designed [typhimurium bacteria was designed [msbB gene, blocking systemic toxicity, and in the purI gene, rendering it incapable of synthesising purines. Since purines are highly detectable in tumours but barely detectable in healthy tissues, these mutations generated a tumour seeking tendency that could be exploited. These bacterial carriers could induce apoptosis via a combination of the expression of tumour suppressor protein P53 and the pro-apoptotic drug Azurin. In a xenograft model of human U87 MG GBM in rats, intracranial injection of bacteria significantly prolonged survival. Histological and proteomic analyses showed no systemic toxicity and a restored neural environment in treated responders.ronments . Throughdesigned . This stdesigned . This stClostridium novyi (C. novyi), an avirulent, highly mobile anaerobic bacteria that is extremely attracted to the hypoxic tumour microenvironment was attenuated and shown to induce an effective anti-tumour response in an orthotopic rat F98 glioma model [C. novyi spore injection, indicating a reduction in tumour volume. C. novyi specifically localised to the tumour, sparing surrounding normal cells and were observed to eliminate islands of microinvasive tumour cells that had diffused within healthy brain tissue. This bacterial treatment also resulted in a significant survival advantage. Abscess formation was not observed in this model with the adequate use of antibiotics. However, abscess formation in the brain remains a potential risk of C. novyi therapy in humans and would require excision and drainage. Given the poor prognosis of gliomas, the benefits of C. novyi therapy might compensate for these potential side-effects. This study also had encouraging results in a canine model, which ultimately led to treating a human patient. In a comparable study, intravenously injected spores of C. novyi led to tumour destruction and significantly prolonged survival in both rat F98 and human 060919 brainstem glioma xenograft models in rats [C. novyi germination was specific to the tumour, with sparing of the healthy brain parenchyma. However, oedema and increased intracranial pressure could have been fatal if not properly managed with hydration and antibiotics.ma model . The tum in rats . As withWhile this review is by no means exhaustive in describing the treatment strategies currently under investigation for treating high-grade gliomas, the aim is to bring to light some of the atypical recent advancements and stratagems that hold potential in advancing glioma treatments in children and adults. Gliomas present an unmet medical need and have done so since being described. The challenges that these tumours present can be seen in the radical strategies being attempted to improve prognosis, and eventually find a curative treatment for this disease. Although the ultimate goal is to defeat glioma, this victory must not be Pyrrhic, with considerations for quality of life intertwined with treatment strategies. Delivery systems and combined modality treatment strategies need to be investigated thoroughly, with events such as neurotoxicity and additive effects of treatment elucidated in efficient experimental models so that a therapeutic index with a favourable benefit-risk ratio can be achieved. Table Declaration of competing interests


SGSM1) has hardly been studied in gliomas. Therefore, we aimed to investigate the prognostic role of SGSM1 and its relationship with immune infiltration in LGGs.Glioma was the most common type of intracranial malignant tumor. Even after standard treatment, the recurrence and malignant progression of lower-grade gliomas (LGGs) were almost inevitable. The overall survival (OS) of patients with LGG varied widely, making it critical for prognostic prediction. Small G Protein Signaling Modulator 1 .We obtained RNA sequencing data from The Cancer Genome Atlas (TCGA) to analyze SGSM1 was significantly down-regulated in LGGs. Functional enrichment analyses revealed SGSM1 was correlated with immune response. Most immune cells and immune checkpoints were negatively correlated with SGSM1 expression. The Kaplan–Meier analyses showed that low SGSM1 expression was associated with a poor outcome in LGG and its subtypes. The Cox regression showed SGSM1 was an independent prognostic factor in patients with LGG .SGSM1 was considered to be a new prognostic biomarker for patients with LGG. And our study provided a potential therapeutic target for LGG treatment. Gliomas were the most common primary intracranial malignant tumors which originated from glial cells –3. AccorSGSM1), located on chromosome 22q11.2, was found to mainly express in brain tissue [SGSM1 with neuronal function. SGSM1 protein was localized in the trans-Golgi network. Furthermore, SGSM1 protein possessed RUN domain and TBC domain which was associated with RAP and RAB-mediated cellular signaling. SGSM1 mediated the interaction between intracellular signaling pathways and vesicle transportation. A recent study has found that SGSM1 degradation led to the invasion and metastasis of nasopharyngeal carcinoma [SGSM1 was a potential candidate gene for schwannomatosis [SGSM1 has hardly been studied and its prognostic value in LGGs remained unclear.Small G Protein Signaling Modulator 1  [https://portal.gdc.cancer.gov/). This study was entirely following the publication guidelines provided by TCGA and GTEx.We downloaded the pan-cancer RNA-seq data of TCGA and GTEx conducted by Toil process uniformly from UCSC XENA (apages/) , 17. ForSGSM1 expression was regarded as the cut-off value to identify DEGs between the two groups (low- and high-expression) of SGSM1 in LGG samples (HTseq-Count), and we used the DESeq2 R package (1.26.0) for analysis [The median analysis .The threshold of DEGs performed for functional enrichment analysis was defined for |logFC| over 2 and adjusted P-value less than 0.05. Gene Ontology (GO) comprising of biological process (BP), cellular component (CC), and molecular function (MF), as well as Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were implemented with ClusteProfiler R package (3.14.3) , 20.SGSM1 expression [We used ClusteProfiler R package (3.14.3) to explore the functional and pathway differences between the two groups of different pression . For eacSGSM1 by single-sample Gene Set Enrichment Analysis (ssGSEA) with the GSVA R package (1.34.0) [SGSM1 and immune checkpoints, including PD1, PD-L1, CTLA4, LAG3, TIM3, TIGIT, and CD48 [We conducted the immune infiltration analysis of (1.34.0) . As ment(1.34.0) . Then weand CD48 .SGSM1 could be used as an independent prognostic factor. We have involved clinical parameters, including age, gender, WHO grade, IDH status, and 1p/19q codeletion. Furthermore, nomogram and calibration plot were generated by the RMS package (version 6.2–0) and survival package (version 3.2–10) for predicting 1-year, 3-year, and 5-year OS [We performed univariate and multivariate Cox regression analyses to evaluate whether -year OS . We have-year OS . In addihttp://www.cgga.org.cn/) [SGSM1.Gene expression data and clinicopathological information of 625 LGG samples were retrieved from two RNA-sequencing datasets of CGGA database (org.cn/) . It was SGSM1 was analyzed by Wilcoxon rank-sum test in unpaired samples. Cox regression analyses assessed the hazard ratios (HRs) and 95% confidence intervals (CIs) of different clinical characteristics, and identified independent prognostic factors. Kaplan–Meier survival analyses and log-rank tests were used to estimate the survival distributions. A two-sided P value less than 0.05 was set to be statistically significant.All the statistical analyses and graphs were conducted by the R programming language (version 3.6.3). The expression of SGSM1 expression between normal tissues and tumor samples from TCGA and GTEx databases, we found that SGSM1 was significantly down-regulated in most types of cancer  of The results of GO functional analysis and KEGG enrichment analysis have been shown below. BP included humoral immune response, lymphocyte mediated immunity, regulation of humoral immune response, phagocytosis, and regulation of immune effector process. CC included immunoglobulin complex, synaptic membrane, synaptic vesicle, ion channel complex, and transmembrane transporter complex. MF included antigen binding, immunoglobulin receptor binding, neurotransmitter receptor activity, passive transmembrane transporter activity, and ion channel activity Fig. a. KEGG iSGSM1 expression level using the MSigDB collection. Among the significantly enriched gene sets, five GO categories, including lymphocyte mediated immunity, phagocytosis, humoral immune response, immunoglobulin production, and immune response regulating signaling pathway, showed significantly differential enrichment in SGSM1 low expression phenotype , NK CD56bright cells (P < 0.001), TFH , Th1 cells (P = 0.042), TReg (P < 0.001), and pDCs  were significantly increased in high SGSM1 group, while aDCs , cytotoxic cells (P < 0.001), eosinophils (P < 0.001), iDCs , macrophages (P < 0.001), neutrophils (P < 0.001), NK CD56dim cells (P = 0.001), NK cells (P < 0.001), T cells (P < 0.001), Tgd , T helper cells (P < 0.001), Th17 cells (P < 0.001), and Th2 cells (P < 0.001) were significantly decreased , NK CD56bright cells , pDC , TFH , and Th1 cells . The negative correlations were found between the SGSM1 expression and infiltrating levels of aDCs , CD8 T cells , cytotoxic cells , eosinophils , iDCs , macrophages , neutrophils , NK CD56dim cells , NK cells , T cells , T helper cells , Tgd , Th2 , Th17 , and Treg  . And the expression level of PD1, PD-L1, CTLA4, LAG-3, TIM3, and CD48 was higher in low SGSM1 expression group than that in high SGSM1 expression group , IDH mutation (P < 0.001), and 1p/19q codeletion (P < 0.001) cases was significantly higher than low-expression group.The main clinical features between low and high SGSM1 expression level with different clinical characteristics , IDH wild-type group (P < 0.001), and 1p/19q non-codeletion group (P < 0.001).Moreover, we evaluated the ics Fig. . The resSGSM1 expression level. The univariate analysis showed that age, WHO grade, IDH1 status, 1p/19q status, and SGSM1 expression level were significantly associated with the OS . Then we analyzed the correlation between risk score, survival time, and SGSM1 expression profiles . We further performed Kaplan–Meier analysis in the subgroups of WHO grade, and the results showed that high SGSM1 expression was correlated with better prognosis in grade II (P = 0.026) and grade III (P < 0.001), respectively.Kaplan–Meier analyses showed the relationship between nts Fig. . PatientThe clinical features were integrated into the nomogram model Fig. a, and thSGSM1 was an independent prognostic factor for LGG prognosis with Cox regression analyses , WHO grade II (P < 0.001) and grade III (P = 0.001), respectively.Using the CGGA database, we validated that SGSM1 was mainly expressed in brain, and it was considered to correlate with small G protein-mediated signal transduction pathway [SGSM1 in LGGs. Our results have shown SGSM1 expression was significantly associated with immune infiltration and OS in patients with LGG.Glioma was the most common type of intracranial malignant tumor . Althoug pathway . There wSGSM1 expression in different tumors. The expression of SGSM1 was significantly down-regulated in most types of cancer, including LGG. Then we analyzed the gene function of SGSM1 with enrichment analyses. It indicated that SGSM1 was related to immune response. With the development of tumor microenvironment research, immune cells were considered to play a complex and important role in tumor progression [In this study, we first compared gression –33.SGSM1 expression with most immune cells. These immune cells were high infiltrated in low SGSM1 expression tumors. We considered the excessive immune response and disorganized immune microenvironment contributed to the short survival of these patients [P < 0.001) had the highest correlation with SGSM1 expression, and the infiltration level indicated the prognosis. Increased infiltration of macrophages in low SGSM1 expression tumors suggested that immune microenvironment was driven from anti-tumor state to immunosuppressive state due to the phenotypic transformation of tumor-associated macrophages, indicated a higher risk of tumor invasion [r = 0.483, P < 0.001) were positively correlated with SGSM1 expression; thus, the infiltration of NK CD56bright cells in tumors was low. NK CD56bright cell had a strong ability to produce cytokines and mainly played an immunomodulatory role [SGSM1 expression and immune checkpoints, including PD1, PD-L1, CTLA4, LAG-3, TIM3, and CD48. SGSM1 potentially influenced tumor immunology, and could be a potential therapeutic target for immunotherapy rather than a simple prognostic biomarker. The ratio of WHO grade II, IDH mutation, and 1p/19q co-deletion were significantly higher in the high SGSM1 expression group. SGSM1 enhanced in subsets of WHO grade II, IDH mutation, and 1p/19q co-deletion groups. It suggested that SGSM1 played a potential role in positive prognostic prediction in some way.Based on the results of enrichment analyses, we explored the immune infiltration levels by ssGSEA. We found a substantial negative connection of patients –36. Amoninvasion . NK CD56ory role , 39. ThiSGSM1 in LGG patients. Cox regression analyses showed that SGSM1 was an independent prognostic factor for LGGs in addition to traditional risk factors, including age, WHO grade, and IDH status. By Kaplan–Meier survival analyses, we found that SGSM1 expression was correlated to the OS. Low SGSM1 expression was related to a poor outcome in LGGs, WHO grade II and grade III, respectively. The survival analyses and Cox regression were validated in the CGGA database. The nomogram prognosis model based on SGSM1 expression level was further established to predict the 1-year, 3-year, and 5-year OS of LGG. The C-index was 0.804 (95%CI = 0.779–0.828). Time-dependent ROC curves and calibration plots illustrated the reliable predictive ability of the nomogram. Our model could provide a new point in outcome prediction and personalized assessment of LGG patients. However, there were still some limitations in this study. Clinical samples should be included for validation. The regulatory mechanism and signaling pathway related to SGSM1 needed further investigation. The prediction model should be verified in future multicenter studies.Then we analyzed the prognostic role of SGSM1 was low expressed in LGGs, and the down-regulation was related to a poor prognosis. Our study has raised a new point of view that SGSM1 was a promising prognostic factor and a potential therapeutic target for LGGs. Our future study will focus on the mechanism of SGSM1 in LGGs.In summary,