Purpose: Previous association studies have investigated whether genetic polymorphisms in HTR1B influenced individuals' susceptibility to major depressive disorder (MDD), anti-depressant response (ADR) and suicidal behavior. However, equivocal evidence was obtained. In this meta-analysis, we aimed to examine the association of HTR1B polymorphisms with risk of MDD, ADR and suicidal behavior.Materials and Methods: Studies evaluating the association between HTR1B polymorphisms and risk of MDD, ADR and suicidal behavior were searched in Pubmed, Ovid Medline, web of science and China National Knowledge Infrastructure databases. Summary odds ratios (ORs), 95 % confidence intervals (CIs) and p-values were calculated using a fixed or random effects model.Results: Meta-analysis findings revealed a significantly increased risk of MDD with rs6296 GC and GC/CC genotypes . Moreover, rs6298 CT genotype was significantly associated with an increased risk of suicidal behavior . However, both rs6296 and rs130058 were not significant risk factors for lethal suicidal behavior.Conclusion: This meta-analysis identified that rs6296 and rs6298 in HTR1B may be significantly related to the risk of MDD and lethality of suicide attempts, respectively. Further studies are required to assess the markers in larger cohorts. Major depressive disorder (MDD) is a common mental disorder that affects about 216 million people worldwide in 2015  and halfThe serotoninergic pathway has been implicated to play a crucial role in the pathophysiology of MDD, antidepressant response (ADR) and suicidal behavior –12. SomeHTR1B gene in humans  and (“SNP*” or “polymorphism*” or “variant*” or “susceptibility”) and . The literature search without language restrictions was carried out up to May 2020.Followed the PRISMA statement, we screened records by conducting computer-based searches of Pubmed, Ovid Medline (1946–2020), web of science (1900–2020) and China National Knowledge Infrastructure (1915–2020) databases using the following search algorithm:  studies published as full-length articles with original genotyping data for computing pooled odds ratios (ORs) and 95% confidence intervals (CIs). The exclusion criteria were: (a) duplicate publications; (b) lack and inaccessibility of data; and (c) meta-analysis. There is no language restriction for inclusion and exclusion criteria.The inclusion criteria for study selection were: (a) association studies reporting From each included study, the following information was independently extracted by two authors (Pingliang Yang and Mengchang Yang) and checked by a third author (Yundan Liang): name of the first author, year of publication, country, ethnic background of participants, total number and mean age of participants, diagnosis and source of patients, criteria used for matching cases, SNPs studied, genotyping distributions, genotyping method, and quality control for genotyping method. Disagreements were solved by discussion among the three authors.HTR1B polymorphisms and the risk of MDD, ADR and suicidal behavior among different genetic models with available data from at least two independent studies. The distributions of SNP genotypes in controls were retested for conformity to Hardy–Weinberg equilibrium (HWE) using a chi-squared test. The Q-test and I2 metric were used to test heterogeneity across studies , a fixed effects model was used to compute summary ORs and 95% CIs  and outcome of anti-depressant therapy (responder vs. non-response and remitter vs. non-remitter). Publication bias was estimated visually using Egger's linear regression asymmetry test . Thirty records were excluded based on no MDD (n = 17), no HTR1B polymorphisms (n = 4), no human study (n = 1) and review articles (n = 8). The full-text of the remaining 62 articles was assessed and 41 records were excluded based on no MDD (n = 10), no HTR1B polymorphisms (n = 6), review articles (n = 5), no available data (n = 18) and duplicate data reporting by the same group (n = 2). Finally, 21 studies evaluating the effect of three polymorphisms in HTR1B  on MDD, ADR and suicidal behavior were included in this meta-analysis.The flow diagram of selection process is presented in The characteristics of the included studies are summarized in HTR1B rs6296 polymorphism and MDD risk, involving 1,230 cases and 1,863 controls, with a statistical power of 93.5% when setting the relative ratio as 1.3 under a dominant model. The rs6296 genotype distributions in controls of all studies conformed to HWE. The frequency of rs6296 C allele was 43.7% in Chinese population, 27.9% in Caucasians and 24.0% in mixed population. Two studies investigated the effect of HTR1B rs6296 polymorphism on the outcome following antidepressant therapy. Regarding the relationship between HTR1B polymorphisms and the risk of suicidal behavior, 11 studies focused on SNP locus rs6296, 3 studies focused on rs130058 and 2 studies focused on rs6298, with statistical power of 99.9, 83.5, and 80.8%, respectively.Eight studies investigated the association between p-value for heterogeneity test are presented in Pooled ORs for the genotypic and allelic comparisons and corresponding HTR1B polymorphisms with the risk of suicidal behavior, meta-analysis findings revealed that rs6298 CT genotype was significantly associated with an increased risk of suicidal behavior . However, both rs6296 and rs130058 were not significant risk factors for lethal suicidal behavior in overall and subgroup analysis in terms of ethnicity , genotyping methods and sample size (>200 and ≤ 200). However, none of these variables can explain the heterogeneity, indicating that there are some unknown factors influencing the heterogeneity.The effect of a single study on summary ORs was evaluated by exclusion of one study each time and statistically similar results were obtained, indicating stability of the pooled ORs.p = 0.02). The bias disappeared after excluding the study with sample size <200 (p = 0.001). The bias disappeared when excluding the studies with sample size <200  have been widely examined in affective disorders. However, results from previous individual studies are contradictory regarding the role of HTR1B polymorphisms in MDD and suicidal behavior. A meta-analysis is therefore valuable with the objective of offering a comprehensive assessment of the effect of HTR1B polymorphisms on the etiology of MDD and suicidal behavior. Our meta-analysis showed that carriers with rs6296 GC and GC/CC genotypes had a 1.26- and 1.22-fold increased risk of MDD, respectively, and carriers with rs6298 CT genotype had a 1.48-fold increased risk of suicidal behavior. Our study has more than 80% power statistics, indicating the results were solid. These findings suggested that both rs6296 and rs6298 in HTR1B were significant genetic risk factors for the development and progression of MDD, which was consistent with the data from genome-wide association study  showed a significantly increased risk of MDD  were also investigated in suicide completers. Then meta-analysis was performed, and we found that the rs6298 rather than rs130058 was significantly associated with an increased risk of suicidal behavior in a heterozygous comparison. Previous work has revealed that rs6296 and rs6298 displayed linkage disequilibrium  were not demonstrated to affect heterogeneity, indicating that uncontrolled confounding factors and inherent selection bias may explain the heterogeneity. Publication bias observed in a few comparisons may be attributed to small sample size since the bias disappeared when excluding the studies with sample size <200. The results remained unaltered after omission of these studies, suggesting that the true association was not overestimated by selective publication of positive results.Notably, most of the published studies focused on the effect of rs6296 on the risk of MDD and suicidal behavior. Only two studies investigated whether rs6296 influenced the outcome of anti-depressant treatment and whether rs6298 influenced the risk of suicidal ideation. Moreover, very limited studies included in our meta-analysis reported detailed information, such as matching criteria between cases and controls and quality control for genotyping assays. Given these limitations in this meta-analysis, genetic association studies are be of great importance using well-designed multi-center cohorts with large samples.HTR1B was significantly associated with the risk of MDD and rs6298 in HTR1B was significantly associated with the risk of suicidal behavior. Further studies investigating the relative contribution of SNPs in HTR1B and the mechanisms by which they affect the susceptibility of developing MDD, ADR and suicidal behavior are warranted.In summary, this meta-analysis identified that rs6296 in The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.YL and SH designed the study and wrote the manuscript. PY and MY managed the literature searches and analyses. PL, DC, DG, LP, and JL undertook the statistical analysis. All authors contributed to and have approved the final manuscript.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.


Controversial results existed in amounts of studies investigating the authentic association of estrogen receptor genes (ESR1 and ESR2) polymorphisms with the occurrence and progression of polycystic ovary syndrome (PCOS). The inconsistency might result from different loci, sample sizes, and ethnicities. To find the potential correlations between ESR1/ESR2 polymorphisms and PCOS risk, we conducted the first systematic review and meta-analysis to comprehensively summarize current studies in a large combined population.Eligible studies were retrieved from PubMed, MEDLINE, EMBASE, Cochrane Library, CBM, CNKI, WANFANG, and VIP up to February 28, 2021. The quality of studies was assessed using the Newcastle–Ottawa Scale (NOS) scoring system. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated to synthesize data in five genetic models. Subgroup analyses were conducted by ethnicity. Heterogeneity and publication bias were also assessed. The protocol was registered in PROSPERO under the number CRD42021239200.A total of 8 studies involving 1,522 PCOS patients and 4,198 controls were included. No evidence demonstrated the association of ESR1 rs2234693 (OR=1.07 95%CI 0.98–1.18), ESR1 rs9340799 (OR=0.99 95%CI 0.69–1.43), or ESR2 rs4986938 (OR=1.06 95%CI 0.81–1.38) polymorphisms and PCOS risk in five genetic models. According to stratified subgroup analyses, ethnicity was considered the major source of heterogeneity. No publication bias was found in eligible studies.The present meta-analysis found no significant associations between the variants of ESR1 rs2234693, ESR1 rs9340799, ESR2 rs4936938, and individual PCOS susceptibility, even if ethnicity was taken into account.https://www.crd.york.ac.uk/PROSPERO) with the ID number CRD42021239200.The protocol was registered in PROSPERO (available from  Although the pathogenesis and etiology of polycystic ovary syndrome (PCOS) remain hitherto unelucidated, it is widely considered multifactorial, that is, both environmental exposure and genetic susceptibility interact with each other and jointly influence PCOS incidence . To dateEstrogen mediates ovarian folliculogenesis and ovulation by binding to estrogen receptor α (ERα) and estrogen receptor β (ERβ), class 1 members of the superfamily of nuclear hormone receptor protein , which pIn recent years, an increasing number of investigations have focused on the potential association of ESR1 and ESR2 polymorphisms with PCOS susceptibility. Nonetheless, some studies held the view that these gene polymorphisms of ESR1 and ESR2 were positively related to PCOS , 17, wheA search of literature was conducted in the PubMed, MEDLINE, EMBASE, Cochrane Library, CBM, CNKI, WANFANG, and VIP. The search period covered the start of the databases to February 28, 2021. The search strategy used to identify eligible studies included (polycystic ovary syndrome OR polycystic ovary OR PCOS OR PCO) and (Single Nucleotide Polymorphism OR SNP OR gene variant OR mutation OR genotype) and (estrogen receptor OR ESR1 OR ERα OR ESR2 OR ERβ), without language restriction. All references cited by these studies were manually screened in order to identify relevant studies.Studies were included if they met all of the following criteria: (1) case-control studies, cross-sectional studies, case series, and cohort studies that were published in peer-reviewed journals; (2) PCOS patients diagnosed with one of the following criteria: the National Institutes of Health (NIH) , RotterdThe titles and abstracts were scrutinized, and the data of included studies were extracted from fully retrieved texts by two investigators independently (SZ and SW). The characteristics of eligible studies were extracted according to Cochrane guidelines. The following contents were extracted: first author, year of publication, country/ethnicity, genotyping method, PCOS diagnostic criteria, the characteristics of cases and controls, HWE, and genotype frequency in cases and controls for ESR1 and ESR2 polymorphisms, respectively. Dissents were noted and resolved by discussing with the third investigator (LX).The Newcastle–Ottawa scoring system (NOS), recommended by the Cochrane Working Group, was conducted to assess the quality of these nonrandomized studies . EvaluatThe HWE was evaluated for each study with a chi-square (χ²) test in the control group by the IBM SPSS statistics 25 software. P> 0.05 indicated that the study population was in HWE. The 95%CI and OR were utilized to evaluate the association strengths of the SNPs of ESR1/ESR2 with susceptibility to PCOS. And five genetic models  were conducted to evaluate the influence of the genotype. The Q-test was used for heterogeneity testing, and the inconsistency index (I²), a test statistic, was used for quantification. In the Q test, when I² ≤ 50%, the fixed-effects model was established to analyze. Otherwise, the random-effects model was performed. Next, a Z-test was performed to evaluate the statistical significance of combined ORs in the quantitative synthesis. When P value < 0.05, it was considered a statistically significant association between SNP mutation and PCOS. Subgroup analyses were stratified by ethnicity, which might be the potential source of inconsistencies. Funnel plots of the outcomes were used to detect publication bias; an asymmetric graph suggested possible publication bias. Egger’s regression test was also applied to assess the publication bias of selected studies, and as proposed by Egger, P value < 0.10 indicated significant publication bias. Sensitivity analysis was performed where appropriate to determine the robustness of the results. All analyses were carried out in the Review Manager software  and the STATA software .A total of 67 potential citations were acquired from electronic databases after exclusion of duplicate articles. Of these, by scanning titles and abstracts carefully, 55 records were removed for irrelevant themes. The remained 12 articles were full-text screened, and another 4 records were excluded subsequently, among which 2 were conference abstracts from the same population, 1 was retracted, and 1 reported non-extractable data. We contacted the corresponding authors for further data; nonetheless, no reply was received. Finally, eight eligible case-control studies that met our criteria were included in the qualitative and quantitative synthesis –23. The The characteristics of each eligible study are listed in 2 statistic indicated that mild heterogeneity was revealed across these studies. Ultimately, no significant association was identified in five genetic models: Allele model (C versus T): OR=1.07 95%CI 0.98–1.18, I2 = 50%; Dominant model (CC+TC versus TT): OR=1.17 95%CI 0.96–1.42, I2 = 27%; Recessive model (CC versus TT+TC): OR=1.06 95%CI 0.90–1.26, I2 = 34%; Heterozygote model (TC versus TT): OR=1.13 95%CI 0.96–1.32, I2 = 0%; Homozygote model (CC versus TT): OR=1.23 95%CI 0.88–1.72, I2 = 51%. Besides, subgroup analyses were performed based on a predefined factor: ethnicity. In Asians, to reduce the influence of severe heterogeneity, the random-effects model was conducted in most genetic models except for the heterozygote model, which showed no significant statistical heterogeneity. In Caucasians, there was no between-study heterogeneity, due to which the fixed-effects model was applied. Likewise, there was no significant association between rs2234693 and PCOS susceptibility in Asians or Caucasians : OR=0.99 95%CI 0.69–1.43, I2 = 89%; Dominant model (GG+AG versus AA): OR=0.99 95%CI 0.60–1.62, I2 = 88%; Recessive model (GG versus AA+AG): OR=1.05 95%CI 0.71–1.56, I2 = 52%; Heterozygote model (AG versus AA): OR=0.96 95%CI 0.60–1.53, I2 = 86%; Homozygote model (GG versus AA): OR=1.05 95%CI 0.60–1.84, I2 = 72%. With severe heterogeneity presented, the random-effects model was applied in every genetic model to synthesize the OR and 95% CI. In subgroup analyses, noticeable heterogeneity was revealed in the Asian population; thus, the random-effects model was chosen for two studies based on Asians. No heterogeneity was found in studies based on Caucasians in which the fixed-effects model was selected. Nonetheless, no statistical association was found in the subgroups of Asians or Caucasians irrespective of whether allele, dominant, recessive, heterozygote, or homozygote comparison of inheritance was used : OR=1.06 95%CI 0.81–1.38, I2 = 70%; Dominant model (AA+GA versus GG): OR=1.10 95%CI 0.77–1.57, I2 = 72%; Recessive model (AA versus GG+GA): OR=1.08 95%CI 0.87–1.35, I2 = 0%; Heterozygote model (GA versus GG): OR=1.07 95%CI 0.75–1.53, I2 = 68%; Homozygote model (AA versus GG): OR=1.10 95%CI 0.87–1.40, I2 = 28%. Subsequently, subgroup analyses were conducted in Asians with high heterogeneity (random-effects model) and Caucasians with low heterogeneity (fixed-effects model). No association was found to be significant in different ethnicities  after excluding this study. For rs9340799, the research of Jiao et al. . Two best-characterized SNPs of rs2234693 and rs9340799 in the ESR1 are located in the first intron, which are 391 and 351 bp upstream of exon 2 and named as PvuII and XbaI, respectively  were detected in more than three studies. Due to the fact that numerous SNPs were reported merely once or twice, for which the results cannot be meta-analyzed, there might be other potential PCOS susceptibility loci. Furthermore, the pathogenesis of PCOS was complicated, which meant a single gene mutation was unlikely to remarkably influence the risk of the disease, while disequilibrium between SNPs in ESR genes might be a risk factor. Second, although eligible studies were conducted in different countries, raw data from Africans were unavailable. We tried to contact the corresponding author, but no response was received. As the distribution of SNPs in different ethnicities was conspicuously distinct, the results should be interpreted with caution. Third, PCOS was defined as a heterogeneous disease for its complicated phenotypes. Due to the absence of biochemical parameters of PCOS patients in eligible studies, subgroup stratification analyses based on phenotypes were unable to be performed. Hence, more well-designed studies with a large sample size and elaborate clinical data conducted in different ethnicities were strongly required.In conclusion, our systematic review and meta-analysis found that the rs2234693 and rs9340799 polymorphisms in the ESR1 gene and rs4936938 polymorphism in the ESR2 gene were not likely to be associated with individual PCOS susceptibility, even if ethnicity was taken into account. The conclusion we draw from the meta-analysis may guide and promote the study of pathogenesis and etiology of PCOS in gene–gene and gene–environment interactions.The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.SZ contributed to the conception of the study. SZ and SW contributed to the selection of articles, evaluation of evidence quality, and extraction of data. SZ performed the data analyses and wrote the manuscript. SW, YS, MY, XS, YC, DK, and LX helped perform the analyses with constructive discussions. All authors contributed to the article and approved the submitted version.This project was supported by Scientific Research Projects of The National Natural Science Fund (81671421 and 81971354).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.


Various studies have shown an association between miRNA polymorphisms and susceptibility to autoimmune disease (AD); however, the results are inconclusive. To evaluate whether miRNA polymorphisms account for a significant risk of AD, a total of 87 articles, including 39431 patients and 56708 controls, were identified to estimate their association with 12 AD subtypes.  Several electronic databases were searched to analyze population-based studies on the relationship between miRNA variants and AD risk. Fixed effects or random effect models were used in the meta-analysis for the risk assessment. P = 0.019; allele model, OR = 1.09, 95 CI: 1.05-1.15, P < 0.001, respectively). Furthermore, miR-196a2 rs11614913 was also associated with AD risk  as well as miR-499 rs3746444 . In addition, associations were observed between miR-149 rs2292832/miR-27a rs895819 and AD susceptibility in the overall population .  In our meta-analysis, miR-146a rs2910164/rs57095329 conferred a marginally elevated risk for AD (allele model, OR = 1.08, 95% CI: 1.01-1.15,  Evidence from our systematic review suggests that miR-146a, miR-196a2, miR-499, miR-149, and miR-27a polymorphisms are associated with susceptibility to AD. Autoimmune diseases (AD) are a spectrum of disorders initiated by impaired self-tolerance of the immune system and may lead to tissue destruction, chronic inflammation, and morbidity . More thMicroRNAs (miRNAs) are endogenously generated single-stranded noncoding RNA molecules of about 22 nucleotides that play a pivotal role in regulating transcription and posttranscription of specific gene expression, including genes of the mammalian immune system . GeneticA robust quantification of the correlation regarding the miRNA-SNPs in patients with AD risk may increase our understanding whether genetic mutations in miRNA sequence are associated with immune-related diseases. Whether shared genetic variations may have similar effects on the risk of different AD or whether these effects are specific for certain AD has not yet been investigated at the genotype level. Although several meta-analyses have already addressed the impact of miRNA polymorphisms on AD risk –27, resuhttp://www.cnki.net/) registry, using the following keywords: “polymorphism,” “SNP,” “variant,” “genotype,” “autoimmune,” “immune-related,” “miRNA,” “microRNA,” and “microRNAs.” Each database was screened from the inception date to December 10, 2020. There were no restrictions as to language, ethnicity, or publication year. Additionally, the citations of retrieved articles were also manually scrutinized for original data sources. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist including the page number for each item can be available in Supplementary Materials  assessment of all miRNA genetic polymorphism association studies, (2) independent case-control study, and (3) having enough data to enable calculating odds ratios (OR) with 95% confidence intervals (95% CI). Articles in the category of reviews, meta-analysis, organizational guidelines, editorial letters, expert opinions, conference abstracts, case reports, and those with insufficient raw data (after contacting the corresponding author) were excluded to avoid duplication and erroneous weighting towards more frequently cited publications. Full text screening of all studies conforming to the above criteria was performed independently by two reviewers (J.Z. and H.T.). Any discrepancy was addressed with a third reviewer (Q.C.) to reach a consensus.A data extraction sheet based on a predetermined standard, including the first author, publication year, type of disease, country, ethnicity, genotyping methods, characteristics of cases and controls, Hardy-Weinberg equilibrium (HWE) in controls, and the modified Newcastle-Ottawa Quality Assessment Scale (NOS), was compiled for each selected study. A study with a NOS score of seven or more points was considered high quality, and those with nine points were ranked the most senior. A kappa value was calculated to compare the data retrieved by the two reviewers (J.Z. and H.T.) . The GraQ value  and quantitative Higgins's I2 statistic. When the I2 statistic was higher than 75%, 50%, and 25%, it represented large, moderate, and small heterogeneity, respectively. Thus, either the fixed effects model (I2 < 50% and P > 0.1) or random effects model (I2 ≥ 50% and P < 0.1) was utilized to measure the pooled ORs and 95% CIs. Furthermore, I2 offers advantages over Cochran's Q statistic and I2 is preferable to a test for heterogeneity in assessing inconsistency across studies [P value less than 0.05 was treated as significant in these comparisons, and all statistical analyses were achieved by STATA V.12.0 software .In our study, the term meta-analysis included our analysis of all miRNA SNPs in the combined AD groups. In the subgroup analysis of specific diseases, sometimes only one study could be found and as such would not meet the definition of a meta-analysis. Mantel-Haenszel OR with 95% CI was computed from the initial raw data; heterogeneity was measured by exploring the study-specific Cochran's  studies . A chi-sn = 18) or for not investigating an association between miRNA-SNP and AD risk (n = 17) or for being a review or meta-analysis (n = 13), expert opinion (n = 3), or case report (n = 5). Ultimately, 94 articles met all the inclusion criteria for our meta-analysis, of which 87 were eligible for quantitative analysis of risk estimates [The initial search retrieved 1478 publications from PubMed, 1603 from Embase, 892 from the Web of Science, 976 from Google Scholar, and 59 from the CNKI. Three extra articles were obtained by scanning the references of preliminary papers –33. The stimates , 31–107.P > 0.05). Apart from two papers, the quality of the evidence generally received a score ranging from five to nine by the NOS criteria. All included studies were graded as “low” quality according to the GRADE profiler, except for one study [In our meta-analysis, AD were classified into twelve disease subgroups, including autoimmune thyroiditis (AITD), arthritis, asthma, systemic lupus erythematosus (SLE), uveitis, inflammatory bowel disease (IBD), Immunoglobulin A (IgA) nephropathy, Kawasaki disease (KD), sclerosis, type 1 diabetes mellitus (T1DM), polymyositis, and psoriasis based on the common syndrome and disease homogeneity risk . We inclne study  which wa87 articles describing 109 studies with 39431 patients and 56708 controls were finally included. Pooling these data, we estimated the miRNA-SNP risk for 23 AD and accomplished a meta-analysis of 12 AD subtypes into the case group. The following paragraphs discuss the epidemiological studies and summarize the genetic susceptibility to AD ).P = 0.019, P = 0.049). After stratifying by disease subtype, it was associated with a decreased risk of IBD . On the contrary, it was correlated with increased risk of arthritis , with asthma , with uveitis , and with psoriasis . A stratified analysis by ethnicity revealed a significant increase in the risk of AD in the Middle East population , but a decreased risk in the Caucasian and Oceanian groups using the recessive model . Subgroup meta-analysis by methodological quality of the studies as ranked by the NOS scale revealed no significant positive association in neither the high-quality studies nor the low-quality studies  in the miR-146a gene were investigated from data retrieved from 71 studies. Meta-analysis indicated that the G allele of rs2910164 was positively associated with AD susceptibility in the overall population . In addition, a stratified analysis based on disease subtype showed that this variant conferred an increased risk of SLE in the allele model and a decreased risk of sclerosis in the recessive model. In the stratified analysis by ethnicity, a significant relationship was detected in the East Asian and Middle East groups . Based on the disease subtype, an obvious association was found in SLE among three genetic models. Our stratified analysis results revealed a significant association in the East Asian and Caucasian groups . Similar results were found in uveitis patients . Furthermore, there was a reduced risk of uveitis in the three genetic models , but an increased risk of T1DM in the allele and recessive model. The stratified analysis results demonstrated that rs11614913 T was significantly related with a decreased risk of AD in the East Asian population  but not the low-quality studies . In the subgroup analysis by disease subtypes, rs3746444 polymorphisms increased susceptibility for arthritis and asthma . On the other hand, a reduced susceptibility was observed for uveitis . A stratified analysis hinted that rs3746444 C delivered an increased risk of AD in the Hispanic and Middle East region  but not the low-quality studies . Subgroup analysis showed an increased risk of arthritis and asthma but a reduced risk of IBD with rs2292832 polymorphisms. Moreover, there was no apparent correlation between other miRNAs and AD susceptibility , which could partly account for the variation of heterogeneity   of miR-196a2 precursor has been reported to influence the efficient processing of mature miR-196a2 and the expression of its target gene 14913 of . An alleStudies have confirmed that miR-499 rs3746444 is located in the pre-miRNA region and influences the binding of target mRNAs to 3p mature miRNA . mir-499The rs2292832 T>C mutation of miR-149 may affect its expression and susceptibility to disease , 63. miRWe did not find associations for several miRNA variants including miR-27a, miR-155, miR-125a, miR-182, miR-585, miR-23a, miR-106a, miR-122, miR-124a, and miR-137. Our analysis did reveal an association between miR-182 rs76481776 and uveitis susceptibility as well as an association between miR-23a rs3745453 and sclerosis.Understanding the specific miRNA-regulated genetic networks and molecular mechanisms by which miRNAs participate in the immune system is a promising area of research and promotes their clinical application. The diagnostic and therapeutic manners of miRNAs have long been acknowledged, which are regarded as clinical biomarkers for monitoring disease evolution during treatment . In the Although we retrieved all current available studies, some limitations of our analysis should be mentioned. First, the disproportionate numbers of cases (range: 0.11%-32.58%) in different AD subtypes might have yielded different sample sizes; thus, the statistical power may show potential heterogeneity. Second, several studies were mainly focused on asthma and Kawasaki disease risk relationship with younger children (younger than five years old), and this may inevitably produce age bias. Third, several groups only contained two studies, which makes it difficult to generalize results, suggesting that larger sample sizes are needed to validate the relationship. Fourth, the current research should be registered in the PROSPERO or Cochrane system, and we hope to do so in future but for the time being would like to mention that our meta-analysis was performed strictly in accordance with the process of systematic review. In addition, the association level identified by current studies was low because of imprecision according to GRADE profiler. Finally, more attention should be made concerning a possible gender bias. However, metaregression did not show that the gender ratio affected our pooled results.Taken together, our meta-analysis provides evidence that miR-146a, miR-196a2, miR-499, miR-149, and miR-27a polymorphisms are associated with AD susceptibility. Some polymorphisms are shared by several AD in certain ethnic groups and/or geographic locations. Some miRNA polymorphisms show protection in some diseases and an increased susceptibility in others. These results provide further support to the complexity of autoimmune disease and suggest that prevention and treatment should be tailored for each specific immune disorder.


Objective: This study investigated the association of the TaqI (rs731236 T>C) polymorphism in the VDR gene with dental caries.Methods: A comprehensive literature search was performed in PubMed, Web of Science, Embase, SinoMed , and the Wiley Online Library. Overall comparisons and subgroup analyses based on ethnicity and the presence of dental caries in dentition were performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess associations between gene polymorphisms and the risk of dental caries.Results: Seven articles were included in this meta-analysis. The pooled results revealed a significant association of the TaqI (rs731236 T>C) polymorphism with dental caries in the allele contrast model  and in the recessive genetic model . A stratified analysis based on ethnicity revealed a significant association between the TaqI (rs731236 T>C) polymorphism and the risk of dental caries in Asians . Subgroup analysis based on the presence of dental caries in dentition found a significant association of the TaqI (rs731236 T>C) polymorphism with permanent tooth caries in the allele contrast model  and the recessive genetic model .Conclusion: The results of this meta-analysis suggest that the C allele and CC genotype of the TaqI (rs731236 T>C) polymorphism in the VDR gene are associated with an increased risk of dental caries. According to the WHO, the decayed-missing-filled index decreased worldwide with the development of stomatology, but dental caries still affect the physical attributes and quality of life of 60–90% of school-aged children and most adults  protein  polymorphism is the most studied variant  that leads to a synonymous change at codon 352 in exon 9, which was significantly associated with several diseases, such as periodontitis, osteoporosis, and multiple sclerosis  polymorphism with dental caries. However, their conclusions are not consistent. Therefore, we performed a meta-analysis to examine the associations between TaqI (rs731236 T>C) polymorphism and dental caries.A considerable number of studies evaluated the association of the TaqI,” “rs731236,” “gene polymorphism,” “dental caries,” “caries,” and “decayed tooth.” We also screened the references cited in the retrieved articles to identify additional qualified studies. Gray literature and other unpublished studies were not included. The publication language was restricted to English and Chinese. We included Chinese as a publication language because of its large population. However, eligible Chinese literature was not searched. Any disagreements between the two investigators were resolved through discussions with another reviewer (Y.X.). The study was performed using the following PICO model:We performed a literature search in PubMed, Web of Science, Embase, SinoMed , and Wiley Online Library; the search was updated on August 31, 2020. The following search terms were used to identify relevant articles: “Population (P): children and adultsTaqI (rs731236 T>C) polymorphismIntervention (I): TaqI (rs731236 T>C)Comparison (C): Outcome (O): Susceptibility to dental cariesTaqI (rs731236 T>C) polymorphism with the risk of caries; (2) case–control studies; and (3) studies with available data to calculate the odds ratios (ORs), 95% confidence intervals (CIs), and p-values. The following exclusion criteria were used: (1) reports that were not case–control studies; (2) case reports, editorials, reviews, and other nonoriginal studies; and (3) duplicate studies.There was no population limit. The following inclusion criteria for eligible studies were used: (1) the study focused on the association of the p-value for Hardy–Weinberg equilibrium (HWE) in the control group.Two investigators (W.L. and H.T.) separately collected the available data using a predetermined protocol. The following items were included: the surname of the first author, publication year, country, ethnicity, age, genotyping method, number of cases, number of controls, and Two reviewers (W.L. and H.T.) independently assessed the quality of the literature on the basis of the Newcastle-Ottawa Scale (NOS) criteria . Any difp-value for HWE in the control group in an eligible study was assessed using the chi-squared test. p < 0.05 was considered a significant divergence from HWE. The associations of TaqI polymorphism with the risk of dental caries were evaluated using ORs with 95% CIs. We performed a Z-test to calculate the statistical significance of ORs, and p < 0.05 was deemed significant. The following models were used for TaqI (rs731236 T>C): allele contrast model (C vs. T), recessive genetic model (CC vs. TT/CT), dominant genetic model (CT/CC vs. TT), homozygous genetic model (CC vs. TT), and heterozygous genetic model (CT vs. TT). We performed subgroup analyses based on ethnicity and the presence of dental caries in dentition. Heterogeneity between the eligible publications was detected using Cochran's Q statistic and the I2 test. A fixed-effects model was used when the Q test demonstrated p > 0.05 or I2 < 50%. Otherwise, a random-effects model was used. All statistical analyses were performed using RevMan 5.3 software (Cochrane Collaboration) and STATA software 12.0 .The A sensitivity analysis was performed to evaluate the stability of the results by successively removing each included study. Begg's and Egger's tests were used to detect publication bias.et al., et al., et al.et al., et al., et al., et al., p-value for HWE, are given in A total of 262 relevant publications were collected from the initial database search. The titles and abstracts of 15 articles were evaluated by reviewing, and 6 studies were eliminated because they were not case–control studies. After systematically reading the full text, two studies were excluded because the data were not available. Therefore, seven articles were included in this research  and the recessive genetic model . No significant association of TaqI (rs731236 T>C) polymorphism with dental caries was found in the other three genetic models  polymorphism and the risk of dental caries in Asians  polymorphism with permanent tooth caries in the allele contrast model . No significant association of the TaqI (rs731236) polymorphism with deciduous tooth decay or mixed tooth caries was found in the five genetic models  polymorphism in any genetic model. All p-values from Begg's test and Egger's test are given in We performed Begg's test and Egger's test to detect the publication bias of each study , 6. We det al., et al., et al., et al., FokI, ApaI, BsmI, Cdx2, and TaqI, with the susceptibility to dental caries were published, and the TaqI (rs731236 T>C) polymorphism was the most studied variant. However, the results of these studies were inconclusive.Dental caries is a multifactorial disease that includes genetic and environmental factors. Vitamin D deficiency is related to enamel hypoplasia, which is associated with an increased risk of caries (Purvis TaqI (rs731236 T>C) polymorphism with dental caries risk. Of the seven studies included in the meta-analysis of TaqI (rs731236 T>C), three studies indicated an association of the TaqI (rs731236T>C) variant with an increased risk of dental caries  polymorphism and the risk of dental caries under the allele contrast (C vs. T) and recessive (CC vs. CT/TT) models. The ethnicity subgroup analysis showed that the TaqI (rs731236 T>C) polymorphism was significantly associated with the risk of dental caries in Asians but not in Caucasians. These results may reflect geographical and ethnic differences. The allele contrast (C vs. T) and recessive (CC vs. CT/TT) models found a statistically significant difference for the permanent dentition subgroup. Notably, these effects were not obtained in the deciduous dentition or mixed dentition subgroups. Bayram et al.  polymorphism may obscure or amplify other gene–gene/gene–environment interactions. Third, although there was no obvious publication bias according to the funnel plot and Egger's test, potential sources of bias may exist because only published studies were retrieved.The main purpose of performing this meta-analysis was to improve the statistical power and obtain more compelling results by increasing the sample size. However, some latent shortcomings of this research cannot be ignored when interpreting the results. First, although we performed a systematic and comprehensive literature search, the number of studies that were ultimately included in the meta-analysis was limited. Second, dental caries is a multifactorial disease. However, the influence of gene–gene and gene–environment interactions was not resolved in our meta-analysis due to a lack of available data. Therefore, the potential role of the TaqI (rs731236 T>C) polymorphism was associated with an increased risk of dental caries. Because of the study limitations, the conclusions of this meta-analysis should be cautiously interpreted. Future studies with larger sample sizes and more ethnic groups are required to achieve more convincing and realistic statistical analyses. The underlying molecular mechanisms of the association between the TaqI (rs731236 T>C) polymorphism and dental caries risk should also be examined.The results of this study suggested that


To meta-analytically determine the adaptation of left ventricular diastolic function (LVDF)-indices to singleton normotensive pregnancies.Literature was retrieved from PubMed and Embase. We included studies that reported a nonpregnant reference measurement and LVDF indices . Mean differences between pregnant and reference measurements and weighted means of absolute values were calculated using a random-effects model.We included 34 eligible studies. Normotensive pregnancies were characterized by an initially larger increase in the passive left ventricular filling  compared to active left ventricular filling during diastole  resulting in a 16% increase of the E/A ratio in the first trimester. The E/A ratio progressively decreased during advancing gestation to −18% at term, resulting from stabilizing E-wave peak velocity and increased A-wave peak velocity. The E/e′ ratio was increased between 22 and 35 weeks  in normotensive pregnancy. Left atrial volume (LAV) progressively increased from 15 weeks onwards with a maximal increase of 30% between 36 and 41 weeks.LVDF in normotensive pregnancy was improved in the first trimester after which LVDF progressively worsened. Large-scale studies in normotensive and hypertensive complicated pregnancies are needed for a more precise insight into LVDF changes during pregnancy. During pregnancy, the maternal cardiovascular system undergoes significant adaptive changes, including a slightly decreased blood pressure, increased cardiac output and plasma volume expansion ,2. TheseAn extensive systematic literature search was conducted on articles evaluating LVDF during normotensive pregnancies using the PubMed (NCBI) and Embase (Ovid) databases. PubMed and Embase provided publications ranging from 1946 and 1974 to July 2020, respectively. The search strategy was originally designed for a series of meta-analyses on cardiac geometry, left ventricular systolic function, and LVDF with a focus on normotensive and hypertensive pregnancies, as detailed in Table 1, Supplemental Digital Content.The identified articles were assessed for eligibility in two phases Fig. . First, Studies were included if they reported a reference measurement, either estimated before conception, at or after 6 weeks postpartum, or in nonpregnant controls, and at least one measurement during pregnancy at any gestational age. Studies needed to report numerical values (mean) with standard deviation (SD), standard error (SE), or a 95% confidence interval (95% CI)). Data was requested in the correct format from authors if they reported their data differently. Exclusion criteria included studies with a study population consisting of women with preexisting cardiovascular disease, or with a history of a hypertensive pregnancy in a previous pregnancy, articles in other languages than English or Dutch, and case reports.Study characteristics , anthropometric measures , and effective measures with SD, SE, or 95% CI were collected from the eligible studies in predesigned data collection forms. LVDF indices collected and detailed were mitral E-wave peak velocity (E-peak), mitral A-wave peak velocity (A-peak), E/A ratio, left atrial volume (LAV), and E/e′ ratio.The eligible studies were all assessed for study quality and risk of bias using a modified list of items described in the Quality In Prognosis Studies (QUIPS) tool, which was adapted for the purposes of this review . Studieset al. and enabled the best categorization of all indices based on the categorization of available literature [I-squared statistic (I2)) is presented as a measure for heterogeneity. I2 can distinguish true heterogeneity from sampling variance and is expressed as a percentage [The gestational age was categorized in five different intervals of gestational age . These gestational age intervals were adapted from Abudu terature . If neceterature . The chaterature . The prircentage . Sourcesn = 1605). Finally, 34 studies were eligible for inclusion  and Doppler or tissue Doppler imaging (TDI). The results of the quality assessment are depicted in Table 3, Supplemental Digital Content.In normotensive pregnancies, E-peak increased in the first 21 weeks of pregnancy (Table P < 0.01). The corrected MD is presented in Table P = 0.67; PC vs. PP and NP P = 0.23) nor study quality  contributed to the observed heterogeneity.Publication bias was present in the 29 to 35 weeks interval P < 0.0. The corIn normotensive pregnancy, A-peak progressively increased from 15 weeks onwards with a maximal increase between 29 and 35 weeks (Table P = 0.005). The corrected MD is presented in Table P = 0.52; PC vs. PP and NP, P = 0.81) nor study quality affected the observed adjustments .Publication bias was present in the 29–35 weeks interval (The E/A ratio increased in the first 14 weeks and progressively decreased from the early second trimester onwards reaching a significant decrease between 29 and 35 weeks (Table P = 0.008). The corrected MD is presented in Table P = 0.37; PC vs. PP and NP P = 0.03). Study quality did not statistically significant contribution to the observed heterogeneity ).Publication bias was present in the <14 weeks of pregnancy interval .Publication bias could not be tested in all intervals because of insufficient studies, except for the 29 to 35 weeks interval (P = 0.27).All studies that reported data on LAV during pregnancy were scored as MQ studies. Type of reference was not associated with the LAV change , respectively. No contributors to the heterogeneity were observed .Publication bias could only be estimated in the <14, 15–21, 22–28, and 29–35 weeks intervals (This systematic review with meta-analysis evaluates the adaptation of LVDF in normotensive pregnancies. Diastolic function is the relaxation phase during the cardiac cycle when the ventricles fill with blood after systole. To the best of our knowledge, this is the first meta-analysis evaluating the adaptation of LVDF to pregnancy.Normotensive pregnancy is characterized by a continuous state of increased cardiac preload, initially due to venoconstriction and later on due to increasing circulating volume ,4. In noTo maintain adequate LV filling, the LA compensates for the increased end-diastolic pressures with an increased atrial kick, as reflected by the increased A-peak. The increased venous return to the LA and the decreased LV compliance is also reflected by the progressive increase of the LAV. LA remodeling is known to play an important role in LVDF and therefore has an indirect effect on overall cardiac performance ,23. If LUnfortunately, longitudinal studies investigating cardiac function in hypertensive pregnancies were very scarce and measurements before 22 weeks of pregnancy were not made, making it impossible to evaluate early adaption of LVDF in women destined to develop gestational hypertensive disorders.The adaptation of LVDF might give additional insights on the cardiovascular adaptation to the hemodynamic load in individual pregnancies in combination with other hemodynamic parameters. Due to the lack of data on LVDF in hypertensive pregnancies, we do not believe that routinely evaluation of LVDF has the potential to discriminate between hemodynamic maladaptive pregnancies and healthy pregnancies. This is relevant because decreased LVDF might precede impaired systolic function and therefore might be helpful to identify high-risk pregnancies.LVDF indices are traditionally measured by TTE in combination with Doppler flow measurements. These traditional measurements are well defined and have been widely applied in echocardiographic studies. A disadvantage is that these measurements are dependent on cardiac loading conditions . TDI is With this meta-analysis we intend to change future study designs that aim at assessing cardiac function during pregnancy, as follows: more traditional doppler parameters should be combined with the less load-dependent TDI and ideally with STE; relevant hormonal, metabolic, geometrical and hemodynamic parameters should be clearly described, along with circulation-modulating drugs used by patients with hypertensive pregnancies; large cohort studies should be set up to allow first and early second trimester changes in cardiac function; different subtypes of gestational hypertensive pregnancies should be evaluated separately.Some longitudinal studies used a postpartum reference and reported pregnant data of the same women. These studies did not report sufficient information to determine the covariance between both measurements. Instead of estimating covariances, their dependence was ignored. We expect that this decision could only have resulted in slightly conservative estimates of precision. Second, the power was not always high enough to reliably test for publication bias. Therefore, the corrected MD should be interpreted with caution.The observed heterogeneity could not always be explained by the study quality and reference group used. It is very likely that other clinically relevant factors are involved, including parity and anthropometric measures. These factors were insufficiently reported, making it impossible to explore their combined relationship.In conclusion, the change in LVDF in early normotensive pregnancy was characterized by an increased contribution of passive LV filling, which resulted in an increased E/A ratio. In advancing gestation, the change in LVDF was characterized by increased active LV filling, which resulted in a progressive decrease of the E/A ratio in the second half of pregnancy. Large-scale studies in normotensive and hypertensive complicated pregnancies are needed for a more precise insight into LVDF changes during pregnancy.Funding: None.Disclosures: None.There are no conflicts of interest.


Ischemic preconditioning (IPC) has gradually been promoted in clinical practice to lower the risk of cardiovascular surgery and postoperative complications. We investigated the role of IPC on vascular endothelial function and the relationship between IPC, flow-mediated dilation (FMD), and brachial artery diameter (BAD).  Systematic searches were conducted in PubMed, Medline, Cochrane Library, Embase, and Scopus databases from their inception to March 20, 2020. This research included randomized controlled trials (RCTs) with adults, and the values of FMD and BAD were considered as the primary outcomes. Ten studies comprising 292 participants were included in the meta-analysis. p < 0.001; I2 = 89.9%). However, the available evidence did not indicate that IPC affected BAD .  Regarding FMD, we observed beneficial effects of IPC on endothelial function (standardized mean difference (SMD): 1.82; 95% confidence interval (CI): 0.64, 3.01;  Our meta-analysis indicated a significant effect of IPC on the endothelial function of the blood vessels, affecting FMD but not BAD. Currently, approximately 120 million people in the US have different forms of cardiovascular disease (CVD), which is considered to be the leading cause of death, morbidity, and disability. In 2016, CVD accounted for about 840,000 deaths in the United States, and the number of CVD deaths increased from 2011 to 2017 by 9.7% . EndotheNowadays, some noninvasive techniques have been developed to assess endothelial functions, such as FMD, which represents an endothelium-dependent, primarily nitric oxide- (NO-) mediated dilation of conduit arteries in response to an imposed increase in blood flow and shear stress. Moreover, impaired FMD has been associated with the predisposition to atherosclerosis and CVD and represents an early process in the development of target organ damage and clinical events . In the IPC, originally proposed by Murry and his group in 1986, is associated with the ability of endogenous mechanisms to produce strong resistance to ischemic damage shortly after nonlethal mild ischemia or reperfusion treatment , 11 haveMany clinical studies have analyzed the effects of IPC on endothelial function. Remote IPC before cardiac surgery increased myocardial salvage and protected endothelial function; additionally, it was safer and more economical than other alternatives . SeveralThis study was conducted to systematically summarize the pieces of evidence for the effects of IPC on endothelial function and conduct a meta-analysis. In this study, two key indicators, FMD and BAD, were evaluated before and after ischemic treatment, and the effects of IPC on endothelial function were systematically examined for the first time in this study. We also evaluated FMD and BAD to further determine the interrelationships between the brachial artery variables and the cardiovascular risk events in a large well-characterized population.Our systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analyses (Supplementary Table: PRISMA-P) , and theFive databases  were used to search for articles from inception until March 20, 2020. Additionally, a manual search of the list of references was performed for the relevant reviews and articles included in the systematic review. A search strategy was developed using the following MeSH and text keywords: intervention (“ischemic preconditioning” or “remote ischemic preconditioning” or “ischemic”) and outcomes .Original studies were included if they met the following inclusion criteria: (1) relevant human intervention studies (subjects ≥18 years old), (2) performed IPC, (3) had a control group, and (4) measured endothelial function, including FMD and BAD.Studies were excluded when (1) they had no information on the intervention or a control group, (2) duplicate publications or substudies of the RCTs were selected, (3) the studies were observational with cross-sectional, case-control, or cohort design, (4) the studies lacked sufficient BAD or FMD information, baseline, or follow-up, and (5) the studies were published in languages other than English.Two independent researchers screened the retrieved articles for eligibility. First, the title and abstract of all the studies were reviewed. Then, the full text of relevant studies was retrieved and assessed to ascertain the suitability of the study for inclusion in the meta-analysis. Any disagreement was discussed and resolved by the third researcher. After data extraction, the following information was recorded in a database: first author's name, publication year, sex, sample size, study design, intervention, duration of the study, and the mean and standard deviation for FMD and BAD in every intervention group and control group. Then, a random-effects meta-analysis was conducted, followed by meta-regression and subgroup analyses to determine whether the effects were modified by health status , age, gender, ethnicity, and treatment duration.The quality of the studies was assessed by two independent investigators using the Cochrane Collaboration risk of bias tool and met the following criteria: “random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting, and other bias.” Based on the recommendations of the Cochrane Handbook, a decision of “yes” indicated a low risk of bias, while “no” indicated a high risk of bias. Labeling an item as “unclear” suggested an unclear or unknown risk of bias , 20. AnyI2 statistic [All statistical analyses for our meta-analysis were performed by the open-source statistical software Review Manager  and Stata version 15 . Inverse variance weighting was used to pool the different studies . Potentitatistic . Sensititatistic  and Eggetatistic .The literature search identified 7,038 articles. Ultimately, ten studies with 12 trials were included in our research. A flow diagram of the process of selecting the studies is shown in In total, 292 participants were listed. The studies included were conducted in America, Europe, and Asia. The intervention period in these studies ranged between one day and eight weeks. The values of FMD and BAD were considered as outcomes.The quality score and risk of bias for each study are shown in p < 0.05, shown in Q = 99.13; I2 = 89.9%; p < 0.05). The results indicated that IPC had a positive effect on the improvement of vascular function. The IPC group increased FMD by 1.82 compared to the FMD in the untreated group. Given that the methods for testing macrovascular and microvascular endothelium-independent reactivity remained largely unstandardized, meta-regression was only performed on the FMD data. Then, we performed subgroup analysis. The remaining heterogeneity after subgroup meta-analyses , which was due to the variations in the characteristics of the populations , different procedures and methods used (measurements of vascular function and intervention duration), and differences in the study design and quality of research. However, the sources of heterogeneity could not be fully determined since the number of included studies and the sample size of the majority of the studies were relatively small.Meta-analysis of the eight sets of independent results showed that IPC did not affect changes in BAD .The sensitivity analyses of FMD with the random-effects models are shown in Overall, the results of the meta-analysis demonstrated that IPC protected endothelial function and improved FMD. However, it did not show any significant increase in BAD following the application of IPC.Murry et al. first described the phenomenon of IPC ; severalEndothelial dysfunction is involved in the development of atherosclerosis, which precedes asymptomatic structural vascular alterations, as well as clinical manifestations of CVD. Endothelial function can be assessed noninvasively using the FMD technique. Therefore, we can improve FMD through IPC and indirectly reduce the risk of related diseases. As an emerging detection indicator, FMD is closely related to the occurrence and development of many diseases. Moreover, brachial artery FMD has been used independently to predict long-term adverse CV events in healthy subjects with no apparent heart disease in addition to being used for assessing some traditional risk factors . BesidesThere are several mechanisms through which FMD could improve endothelial function and might account for the beneficial effects observed in this study. First, cardiovascular protection provided by the early phase of IPC is mediated by the stimulation of receptors linked to protein kinase C (PKC) activation by adenosine, bradykinin, NO, and free radicals –45. ReceIn conclusion, our findings indicated that IPC augmented the endothelial function through an increase in FMD. It is important to select an appropriate intervention that is effective in improving or augmenting endothelial function. IPC has the potential for improving endothelial function as a novel method for predicting and preventing cardiovascular diseases associated with endothelial dysfunction. Besides, the idea of providing significant myocardial protection with transient limb ischemia is highly attractive to clinicians because it only requires a blood pressure cuff . As a siThe overall quality of the studies included was the modest. The majority of the investigations did not allow blind participants to the intervention arm, and no study reported methods of allocation concealment. Additionally, given the small number of studies included in this review, our analysis might have been underpowered to detect differences in the effectiveness of interventions based on health status, type of measurement, and study design. Differences in the effect size among the included studies could have been affected by the coexistence of traditional CVD risk factors  and the concomitant treatments. Further investigation is needed to establish the applicability and safety of IPC in clinical populations. The consideration of the other factors related to changes in cardiovascular risk is also warranted.


There is growing evidence for the possible use of microRNAs (miRNAs) in cancers as diagnostic as well as prognostic biomarkers in the present era of Personalized Medicine. The objective of the present systematic review and meta-analysis was to assess the prognostic role of microRNAs in uterine cervical cancers.  A systematic review and meta-analysis was carried out searching electronic databases for published articles between January 2009 and August 2020 based on standard systematic review guidelines. Meta-analysis was performed by pooling the hazard ratio (HR) with 95% confidence interval (CI) to assess the prognostic value of deregulated miRNAs by the random-effects model. In the present meta-analysis, the aberrant expression of 14 microRNAs in 1,526 uterine cervical cancer cases before definitive therapy from 14 case-control studies were assessed. The pooled HR of two miRNAs, miRNA-155 and miRNA-224 which were upregulated in cervical cancer tissues was 1.76 (95% CI 1.27-2.45) revealing significant association with overall poor survival. Meanwhile, the pooled HR was 1.53 (95% CI 0.94-2.94) when all the deregulated miRNAs in cervical cancer tissues were evaluated. The pooled HR of downregulated miRNAs was 1.46 . Meanwhile, the pooled HR of three upregulated miRNAs-425-5p, 196a, 205 in the serum sample was 1.37 (95% CI 0.45 -4.20). The downregulation of aberrant miRNAs was not associated with poor overall survival rates. Cervical cancer is the fourth most common female cancer after breast cancer, colorectal and lung cancer . India is home to 453.02 million women aged 15 years and above who are at risk of uterine cervical carcinoma and is the second most common cancer among Indian women. Despite being a preventable cancer by Human Papillomavirus (HPV) vaccination and cancer screening, one-fourth of the global burden of cervical cancers was contributed by India alone. Cervical cancer survival rates are highly variable across India and five-year age-standardized relative survival rate is much lower compared to other Asian countries such as China, South Korea, Singapore and Thailand .®)–Health Professional Version - National Cancer Institute,” 2020). In the absence of organized screening programs in India, most women present at advanced stages. Timely detection and management become almost impossible due to non-specific symptoms in the early stages and the absence of organized screening programmes in developing countries. The search for an efficient biomarker for early diagnosis is challenging owing to uncertain cellular and molecular mechanisms of cervical cancer oncogenesis. The most common type of cervical cancer is squamous cell cancer constituting about 90% of uterine cervix cancers followed by adenocarcinoma comprising almost 10%  were discovered. MicroRNAs may function as oncogenes or tumor suppressors at various targets in human cancers leading to aberrant expressions. Recent studies carried out in the last decade reported dysregulation of some microRNAs in cervical cancer oncogenesis. MicroRNAs regulate about 30% of human genes  and 50% of these genes are tumor-related or situated in fragile loci . Upregulation of miR-155 and miRNA-224 was observed to be poor prognostic factors in cervical cancers . Meanwhile downregulation of certain microRNAs was reported to imply poor prognosis in cervical cancers. These markers are stable in serum and are expressed in tissues. Why it is important to do this reviewSeveral years of cytology screening in low- and middle-income countries have not led to a significant reduction in cervical cancer cases which is attributed to financial and technical hurdles in carrying out cytology as well as Human Papillomavirus (HPV) DNA testing, non-compliance for follow-ups and timely management of screen-positive women. Identifying efficient biomarkers for early detection and appropriate management of uterine cervical cancers which can be translated from bench to bedside is the need of the hour. We performed a systematic review and meta-analysis regarding the prognostic value of microRNAs in uterine cervical cancers. A systematic review and meta-analysis of literature was performed searching electronic databases for published articles in English between January 2009—August 2020 based on standard systematic review guidelines. The present rearch work comply with the Preferred Reporting Items of Systematic reviews Meta-Analyses (PRISMA) statement . The meta-analysis component was modified appropriately to evaluate the prognostic value of miRNAs in cervical cancer.Description of the conditionMicro RNA or miRNA: MicroRNAs are short non-coding, single-stranded RNAs having 18-25 nucleotides length, which regulate gene expression at the post-transcriptional level through target messenger RNAs (mRNAs) and suppress translation or induce mRNAs degradation. Utilizing several molecular mechanisms, microRNAs play a vital role in the origin and progression of cancers, either as oncogenes or as tumor suppressors.Prognosis: Prognosis is the chance of developing cervical cancer or possibilities of getting better after developing cancer. In the present research, the prognosis is reported in terms of overall survival rate due to cervical cancer.Biomarker: Biomarker is a characteristic that can be measured implying normal biological processes, pathogenic processes or responses to an exposure or intervention . A pathological or physiological process can be recognized by testing for a natural gene, enzyme or protein. Study protocolAn electronic search of PubMed/MEDLINE and SCOPUS was carried out using search terms such as miRNA OR microRNA AND cervical cancer AND “survival”. Retrospective case-control studies, employing quantitative real-time polymerase chain reaction (qPCR) for miRNA profiling in cervical squamous cell cancers were chosen for meta-analysis. The published articles in English since 2009 were explored and a manual library search for articles in peer-reviewed journals was performed. The references of retrieved articles were also examined to increase the search sensitivity. miRNA expression in cancer tissue and matched adjacent normal cervical tissue samples or in serum samples of uterine cervix cancer cases belonging to clinical stages I-IV as per International Federation of Gynecology and Obstetrics  classification  were included for the meta-analysis. Case-control studies employing quantitative real-time polymerase chain reaction (qPCR) for miRNA profiling were included. Inclusion process and criteria: Articles regarding All the included studies categorized the samples into low expression and high expression groups based on the mean or median cutoff value of miRNA amplified. The overall survival rate was reported as hazard ratio (HR) with 95% confidence interval (CI) to evaluate the prognostic value of microRNAs. Exclusion criteria: Duplicate publications of the same survey and articles published in languages other than English were excluded. Studies reporting microRNA profiling by microarray were also excluded as these assays are less specific without absolute quantification. MicroRNA profiling extracted by bioinformatics assays, studies reporting only relative risk (RR) and articles with no information on histology of cancers were also excluded. Data extraction A validated proforma focusing on the first author, year of publication, region, sample size, histology, lymph node involvement, duration of follow up, miRNAs amplified, cut-off value, HPV status, and hazard ratio (HR) with 95% CI was used to extract the data.rd August 2020. In this systematic review, the three-stage selection process was carried out for the final inclusion of the studies. One reviewer assessed titles from 4688 records for the relevance for inclusion in the study. Studies applicable for the review were moved to the second stage and articles in languages other than English, irrelevant articles and duplicates were excluded (n= 4443). In the second stage, the abstracts of the studies (n=245) were obtained and two reviewers independently analyzed all the abstracts. All the non-relevant studies were rejected (n=192) and the remaining (n=53) studies were moved to the third stage. Full texts of studies (n=53) were retrieved which were again examined by two reviewers independently. Extracted data from full-text articles by the first reviewer was further reviewed by a second reviewer. Any difference of opinion was settled by discussion. A total of 32 studies were systematically reviewed. Detection of miRNA in cervical cancer cases from 14 case-control studies were included in the quantitative synthesis . The study selection process is depicted in the PRISMA chart . The lasQuality assessmentUtilizing New Castle Ottawa scale (NOS), two reviewers independently and systematically assessed the quality of case-control studies  Data analysis Considering the inclusion of possible confounding factors, articles reporting hazard ratio from multivariable Cox Regression analysis were included for meta-analysis. Adjusted hazard ratio (HR) along with 95% Confidence Interval (CI) from multivariable Cox Regression analysis were extracted from each of the 14 studies qualified for meta-analysis. These hazard ratios were synthesized in a meta-analysis to obtain a pooled HR with 95% CI to evaluate the prognostic effects of miRNAs on the survival of uterine cervical cancer. Meta-analysis was performed using a random-effects model in STATA 13.1 statistical software .using the “Metan” package. Chi-square statistic and I-squared statistic were used as measures of statistical heterogeneity. The results of the meta-analysis are depicted in a forest plot, where the diamond represents the pooled estimate with 95% CI.microRNA. The I2 statistic was computed to test the significance of potential heterogeneity. Forest plots were separately generated for miRNA expressed in tissue and serum samples. In both the meta-analyses a subgroup analysis was carried out based on the high or low expression of Publication biasThe publication bias was evaluated by Egger’s test which includes weighted linear regression with standardized effect estimate, the dependent variable and precision as the independent variable(“(PDF) MIDAS: Stata module for meta-analytical integration of diagnostic test accuracy studies | Ben Dwamena - Academia.edu,” n.d.). In the present study, loge HR was considered as the effect estimate and the precision was given as 1/standard error of loge HR. Weights were allotted by the inverse variance approach (1/variance of the effect estimate). A statistically significant bias coefficient gives evidence for the presence of publication bias.Included studiesThrough electronic search, full texts of 32 articles were reviewed systematically and 14 studies were included for quantitative synthesis. Characteristics of the included studies are shown in microRNA expression in cervical cancer tissues. As shown in The studies qualified for meta-analysis were all from China, the world’s most populous country. Studies reporting the prognostic value of 14 aberrant microRNAs in tissue or serum samples of 1,526 uterine cervical cancer cases prior chemoradiation were included for meta-analysis. Out of the fourteen qualified studies, ten articles reported 361-3p expression when compared to healthy controls . Zhou et al., (2018) also reported lower RFS and overall survival with downregulation of miR1254.The present systematic review observed that four studies reported the recurrence-free survival rate (RFS) apart from overall survival. Out of the 14 qualified studies, only two recent studies generated recurrence-free survival rate (RFS) from Kaplan Meier curves other than overall survival rate (OS)  Deceased patients and cases having recurrence were found to have a lower Quantitative synthesismiRNA expression. The HR with 95% CI  were pooled for miRNAs with low or high expression in tissue samples and analyzed by forest plot . The pooled HR of three upregulated miRNAs-196a, 215, 425-5p in serum samples was 1.37 (95% CI 0.45 -4.20) implying a lack of significant association with overall poor survival . Pooling2 ≥ 50%, indicating considerable heterogeneity, the random-effects model was adopted for pooling. Compared to previous meta-analyses considerable heterogeneity was observed as more number of studies with different miRNA profiles were pooled. As the IPublication biasThe p-value for the bias coefficient was not statistically significant  and 4. HmiRNA-224 was reported to be an independent predictor of poor prognosis, lymph node metastasis and shorter overall survival . MicroRNA-155 is an oncomir which promotes malignant transformation in many human cancers such as cervical cancer, lung cancer, leukemia and breast cancer . Tumor suppressor gene, LKB1 encoding serine/threonine kinase was identified as the potential target of miRNA-155 based on bioinformatics analysis. In cervical cancer cells LKB1 gene was reported to be downregulated . PTX3 was reported to be the target gene for miRNA-224 when analyzed by bioinformatics as well as dual-luciferase reporter assay. Overexpresssion of miRNA-224 and silencing or under expression of PTX3 was related to aggressive progression of cervical cancers .These observations may facilitate the development of potential therapeutic agents against cervical cancer in future. Deregulated expression of microRNAs leads to silencing of the target gene which may be affecting the response to various chemothrepeutic agents . The preservation of certain miRNAs-361-3p, 1254, 664, 155, 26b, 503,145,125a, 126, 224, 101, 425-5p, 196a, 205 in cervical cancer was observed to be associated with improved overall survival and better prognosis . The present meta-analysis observed upregulation of two micro RNAs-155 and -224 in tissues was related to poor prognosis and reduced overall survival. Upregulation of oncogenic miRNA-155 and miRNA-224 was noted in HPV positive cervical cancers . Increased expression of miRNA expression in tissue is more specific for assessing the prognostic value in site-specific cancers. Studies with histological classification were included in the present meta-analysis and except one study squamous cell carcinoma cases was the predominant type in all the 13 articles  which pooled HR from nineteen studies. Dai et al., (201) observed the association of low miRNA with poor survival. Another meta-analysis of seven studies by Chen et al., (2018) observed that poor survival was associated with low levels of miRNA-125, miRNA-145, and a high level of miRNA-196 in tissue samples. We observed vast variation in the histological types of cancer in the studies included by Chen et al., (2018) as well as Dai et al., (2018) which pooled HR from studies carried out in serum and tissue samples in a single meta-analysis. Compared to serum, aberrant articles . SeparatmiRNA expression in cervical cancers was attributed to persistent high-risk HPV infection . Limited number of reviewed studies reported Human Papillomavirus association along with miRNA profiling as in miRNA-361-3p expression in high-risk HPV DNA positive cervical tissues when compared to normal tissues without HPV infection. However, a significant difference in miRNA-361-3p expression was not observed between cervical cancer tissue and normal tissue . Downregulation of tumor suppressor miRNA-145 was observed in HPV positive uterine cervical squamous cell cancers with vascular invasion . There was no significant correlation between HPV positivity and certain tumor suppressors such as miRNA-1254, and miRNA-664 . Chromosomal instability caused by HPV is attributed to upregulation of microRNA-9 in uterine cervical cancers . Fan et al., (2015) reported HPV-induced p53 inactivation resulting in microRNA-125a downregulation. The causal role of Human Papillomavirus (HPV) in cervical cancer is well proven and aberrant Strengths of the studymiRNA expression. Estimates of HR were obtained only from multivariable Cox regression analysis. There was uniformity in the tissue samples preserved for the study in the present meta-analysis.Separate meta-analyses were performed for tissue and serum samples. Subgroup analysis was also performed for differential There were several limitations of our meta-analysis. Except for one study, all the included studies incorporated adjacent normal cervical tissue from cervical cancer cases as controls. There was ambiguity regarding the microscopic examination for malignant changes. There was no uniform cut-off levels even though median or mean cut off values were used in the included studies. Due to the scarcity of published research on the microRNAs, we had to pool different microRNAs for evaluating the prognostic role. However, miRNAs reported to be deranged in at least two research publications were selected for the meta-analysis. Amongst the qualified studies miRNA-155 and -224 were upregulated in tissue samples which was significantly associated with poor overall survival in cervical cancers. This should be interpreted with caution as the pooled HR was generated from only two published articles. RecommendationsFuture research including cervical tissues from women with no cervical cancers as controls is needed. Research work on upregulated microRNAs has to be undertaken among cervical cancer cases wordwide. Large prospective studies are needed to assess the prognostic value of microRNAs in cervical cancer. In conclusion, the downregulation of miRNAs was not associated with poor overall survival rates in cervical cancer. SS and NR and conceptualised the study and developed the research protocol; SS and NR identified articles for full-text review, extracted data from studies, and matched inclusion criteria. N R did the statistical analyses. SS drafted the study. Both the authors approved the final study, and NR agreed to be accountable for all aspects of the work in ensuring that questions related to the integrity of any part of the work are appropriately investigated and resolved.