Bipolar disorder (BD) and temporal lobe epilepsy (TLE) overlap in domains including epidemiology, treatment response, shared neurotransmitter involvement and temporal lobe pathology. Comparison of cognitive function in both disorders may indicate temporal lobe mediated processes relevant to BD. This systematic review examines neuropsychological test profiles in euthymic bipolar disorder type I (BD-I) and pre-surgical TLE and compares experimental designs used.A search of PubMed, PsychINFO, and Scopus using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. Inclusion criteria were comparison group or pre- to post-surgical patients; reported neuropsychological tests; participants aged 18–60 years. Fifty six studies met criteria: 27 BD-I; 29 TLE.Deficits in BD-I compared to healthy controls (HC) were in executive function, attention span and verbal memory. Deficits in TLE compared to HC were in executive function and memory. In the pre- to post-surgical comparisons, verbal memory in left temporal lobe (LTL) and, less consistently, visuospatial memory in right temporal lobe (RTL) epilepsy declined following surgery. BD-I studies used comprehensive test batteries in well-defined euthymic patients compared to matched HC groups. TLE studies used convenience samples pre- to post-surgery, comparing LTL and RTL subgroups, few included comparisons to HC (5 studies). TLE studies typically examined a narrow range of known temporal lobe-mediated neuropsychological functions, particularly verbal and visuospatial memory.Both disorders exhibit deficits in executive function and verbal memory suggestive of both frontal and temporal lobe involvement. However, deficits in TLE are measured pre- to post-surgery and not controlled at baseline pre-surgery. Further research involving a head-to-head comparison of the two disorders on a broad range of neuropsychological tests is needed to clarify the nature and extent of cognitive deficits and potential overlaps. Bipolar disorder type I (BD-I) is typically characterized by episodes of mania and depression with inter-episode euthymia. A number of impairments have been noted in the euthymic phase of the illness including social, occupational functioning, and cognitive deficits , 2.Most studies have examined cognitive deficits in euthymic patients with BD-I compared to healthy controls (HC). Five meta-analyses have reported impairments in cognitive domains of executive functioning –7, verbaAn alternate research design is to compare and contrast cognitive deficits in BD-I to a reference condition which shares common features. For example, a meta-analysis comparing BD-I and schizophrenia reported more pronounced cognitive deficits in schizophrenia on measures of verbal fluency, verbal memory, executive function, visuospatial memory, mental speed, IQ, and concept formation . Similarn = 26, TLE n = 9). A case can be made for further exploration of similarities and differences between the neuropsychological test profiles seen in euthymic BD-I and interictal TLE. This is particularly so given the localizing pathology of TLE, which allows inferences to be made regarding the contribution of temporal lobe processes to the range of cognitive deficits reported in BD-I.A single study compared BD-I with complex partial seizure disorder . It is nThere are a number of established similarities between BD-I and TLE. These typically include a chronic course punctuated by episodic manifestations of mania and seizures, respectively. Other similarities include: the proposed involvement of kindling mechanisms ; changesIn addition, episodes in both disorders commonly feature sensory, perceptual, cognitive, and affective changes  includinThe temporal lobes have also been the subject of neuroimaging research in both disorders. In BD-I many studies have investigated correlates of the disorder to specific brain regions. Meta-analyses of magnetic resonance imaging (MRI) studies have reported that BD-I is associated with right lateral ventricular enlargement  and an eIn TLE, MRI studies have reported structural brain abnormalities in the hippocampus, entorhinal cortex , thalamuGiven these potential diffuse structural abnormalities seen in patients with TLE, it could be expected that neuropsychological deficits may not be limited to tasks involving temporal lobe function. Patients with TLE display deficits in memory, general intelligence, language, executive function, and motor speed relative to HC , 35. DefThe literature describing clinical features, imaging findings, and neuropsychological test profiles is largely in a separate corpus for BD-I and for TLE with only one small study directly comparing the two .The current structured review brings these two bodies of work together in a comparison of the neurocognition literature findings of the two conditions side-by-side. The aim is to determine whether and to what extent the cognitive impairments seen in euthymic BD-I are mirrored by those attributed to a pathology primarily affecting the temporal lobes, that is TLE.This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines .Inclusion criteria: (a) controlled comparison, (b) patients diagnosed with BD-I as assessed by a recognized criterion-based diagnostic system, (c) BD-I patients rated as euthymic, defined by their scores on a rating scale ; patients with unilateral TLE, from any cause, with diagnosis confirmed in a pre-surgical workup, (d) at least one neuropsychological test, (e) adult participants (18–60 years), (f) in the case of more than one article by the same authors results were not identified as being from the same sample, (f) articles published 1980 or later.A comprehensive search of the electronic databases PubMed, PsychINFO, and Scopus for peer-reviewed articles published in English was conducted in the last week of May 2016. Search terms were grouped as follows: bipolar, manic depress*, baseline, asympt*, remit*, stable (group 1); or epilep*, seizure, presurg*, temporal, focal, partial, complex, interictal (group 2) and WAIS, Wechsler, trail making, continuous performance, stroop, digit span, verbal learning, rey, working memory, benton, card sort*, verbal fluency, RAVLT, CAVLT, tower of London (group 3). These search terms were combined as follows: group 1 AND group 3 for BD-I and group 2 AND group 3 for TLE.The abstracts located from the search strategy were entered into EndNoteX7. The PRISMA flowchart Figure  sets outThe search strategy identified an initial 3,307 articles of which 56 met inclusion criteria, 27 related to BD-I and 29 to pre-surgical TLE. Studies of BD-I are summarized in Table n = 1,398) to HC . The remaining studies compared manic, euthymic, and depressed groups. The most commonly reported impairments in BD-I were in executive function, attention span, and verbal memory. No studies found enhanced neuropsychological function in euthymic BD-I.As demonstrated in Table n = 150) to HC (n = 111); these studies found significant impairments in TLE compared to HC on tests of memory and executive function.As shown in Table n = 846) or the left temporal lobe . In pre-surgical TLE, the direct comparison of LTL and RTL groups indicated that the LTL group showed impaired verbal memory and the RTL group, less consistently, impaired visuospatial memory.In 26 of the TLE studies, the samples were divided by laterality of seizure focus with the primary pathology affecting the right temporal lobe , consequently the findings have limited depth compared to those in the BD-I literature . The pre-surgical neuropsychological workup consists mostly of tests of memory function, which is not surprising given that the surgery involves removing parts of or the whole temporal lobe.There are significant differences in the experimental designs examining cognition in the two patient groups. In BD-I studies, cognition is tested broadly with a wide range of measures, with a HC comparison group and statistical control for medication use. This allows for observed deficits to be interpreted as trait markers of BD-I. This is further supported by familial studies that show similar patterns of impairments among family members and patients . By contIn general, the studies on BD-I report the types of medications taken by patients at the time of testing , time of testing, hospitalizations, and the presence of psychotic features were not considered in this review. In BD-I patients, the presence of sub-clinical symptoms is common, even in those patients who are rated as euthymic at the time of testing and may have impacted performance overall .Although there is wide variation in the diagnostic criteria of euthymia, our study aimed to control for this by using the HAMD and YMRS as cutoffs; however, longitudinal measurements would have been advantageous to characterize proximity to manic or depressive episodes. Residual mood symptoms are also an important consideration in epilepsy where depression is the most common psychiatric comorbidity . In commWe suggest a strong case may be made for a study comparing neuropsychological tests to assess deficits in BD-I, TLE, and matched HC. In future research, a comprehensive test battery employing tests of attention, executive function, memory, and psychomotor speed, coupled with imaging techniques, should be employed in both disorders relative to HC. This would provide valuable information on the effects of both BD-I and TLE on temporal and other cerebral areas as well as the effects of medication on neuropsychological test parameters. This would also be of value in identifying putative temporal lobe involvement in BD-I.EB, KK, MG, and BT contributed to the design of the project, the analysis and discussion of the results and write up of the paper with KK, MG, and BT contributing their specialist perspective. EB and KK assessed the suitability of papers for inclusion in the manuscript and contributed to the PRISMA review.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.


Mycobacterium tuberculosis leads to reactivation of latent infection into the active pulmonary disease. However, heterogeneous nature of TB and failure of rationally designed vaccines in clinical trials raises serious questions against the simplistic view of TB as an outcome of weakened immunity. In the wake of accumulating human TB data, it is argued here that a hyperactive antimycobacterial immune response is to blame for the pathogenesis of pulmonary TB in immunocompetent adults. Direct and indirect evidence supporting this notion is presented in this article. Revisiting the role of immune system in TB pathogenesis will pave the way for effective anti-TB vaccines.The intricate relationship between tuberculosis (TB) and immune system remains poorly understood. It is generally believed that weakening of the immune response against  Mycobacterium tuberculosis (Mtb) infection into the active pulmonary disease. Although a major support to this notion is provided by the significantly elevated risk of TB in immunocompromised hosts (such as those suffering from HIV/AIDS), TB in immunocompromised people is different from that occurring in immunocompetent adults.Tuberculosis (TB) continues to be one of major global health threats resulting in nearly 1.5 million deaths per year [Mtb infection in immunocompromised hosts leads to a primary progressive disease, commonly affecting extrapulmonary sites and often occurring in a severe form. Owing to its heterogeneous presentation and pattern of occurrence, an increasing number of researchers have been questioning the simplistic view of TB as an outcome of weakened immune response. Failure of rationally designed vaccines, e.g. MVA85A (modified vaccinia virus Ankara expressing Mtb antigen 85A), which had been aimed at boosting antimycobacterial immune response, further raises the serious concerns about our current understanding of the TB immunobiology.In immunocompetent adults, TB occurs as a post-primary and localized disease affecting mainly lung tissue. On the contrary, On the other hand, a number of experimental and observational studies have shown that a heightened immune response is closely associated with active pulmonary TB or its elevated risk in immunocompetent adults. Based on these and other findings, it is proposed here that a hyperactive antimycobacterial immune response is to blame for the pathogenesis of adult pulmonary TB in immunocompetent hosts. Direct and indirect evidence supporting this notion is presented in this manuscript. Protective immunity in TB is briefly described in the beginning, which is followed by the findings favoring the pathological role of hyperactive immune response in adult pulmonary TB. Finally, heterogeneity of TB and its role in complicating TB immunobiology has been discussed in short.Mtb begins with inhalation of bacilli-laden droplets, produced by an active TB patient while coughing. Inside lungs, Mtb is recognized and phagocytosed by resident macrophages. These cells respond to Mtb infection by producing proinflammatory cytokines and chemokines, reactive nitrogen/oxygen species and antimicrobial peptides [Mtb-specific CD4+ and CD8+ T cell responses.The immune response to peptides . Monocytpeptides . After m+ T lymphocytes are the key orchestrators of protective immunity against Mtb [Mtb is evidenced by CD4+ T cell-lymphopenic HIV-infected people, who have 20–35 times higher risk of TB, compared with uninfected individuals [+ T cells act primarily by activating macrophages through soluble factors like IFN-gamma and TNF-alpha, and cell surface molecules such as CD40 [Mtb growth and killing the intracellular bacilli in an inducible nitric oxide synthase (iNOS)-dependent manner. Activated macrophages have also been shown to enforce phagolysosomal fusion, which is otherwise inhibited by the pathogenic mycobacteria.CD4inst Mtb . The criMtb [Mtb-infected macrophages is enhanced in the presence of TNF-alpha, leading to the elimination of intracellular Mtb [Mtb is highlighted by reactivation of latent infection in people (such as rheumatoid arthritis patients), who have been treated with anti-TNF agents [Proinflammatory cytokines TNF-alpha and IFN-gamma are the important mediators of protective immunity against Mtb . TNF-alpMtb . Furtherular Mtb . TNF-alpular Mtb . The impF agents .Mtb-infected hosts, IFN-gamma is mainly produced by CD4+ T cells, although CD8+ T cells, γδT cells, NK cells and NKT cells also contribute towards it [Mtb-infected DCs and macrophages. Mutations in IL-12/IFN-gamma axis predispose the affected individuals to progressive mycobacterial infection [In wards it . Productnfection . A partinfection .Mtb results in the well-organized cellular fortress, which can effectively shield healthy lung tissue from Mtb. This fortress, referred to as granuloma, has infected macrophages, neutrophils, giant cells and epithelioid cells in its core, which is surrounded by CD4+ T cells, CD8+ T cells, B cells, and fibroblasts [Mtb residing in their granulomas do not develop active disease and remain healthy lifelong, illustrating the protective role of granulomas against Mtb.The coordinated response of innate and adaptive immune systems against roblasts . Granuloroblasts . Most ofMtb immune response, characterized by excessive CD4+ T cell activity and IFN-gamma levels, is to blame for the pathogenesis of adult pulmonary TB in immunocompetent hosts. This evidence is presented below.Like any other thing in excess, the excessive immune response is not good for health and it holds true for the antimycobacterial immune response as well. Studies have shown that most of the adults pulmonary TB patients are not immunodeficient and are not susceptible to other infectious diseases in general. On the other hand, a number of evidence shows that a hyperactive anti-Mtb. It involves the intradermal injection of purified protein derivative (PPD) and monitoring for a delayed-type hypersensitivity (DTH) reaction, which is seen as the local skin induration (tuberculin reaction) [+ T cells and macrophages, against an antigen (or antigens) to which an individual is prior sensitized. The occurrence of an intense DTH reaction in adult pulmonary TB patients, as demonstrated by the large area of induration, shows that these individuals mount and maintain the higher levels of cellular immune responses to Mtb antigens [Tuberculin skin test (TST) is a widely used assay to diagnose exposure to eaction) . DTH is antigens .Mtb antigens, indicating that a moderate anti-Mtb immune response is able to confer protection against active disease [Studies on the close contacts of TB patients have shown that those who initially exhibited a greater sensitivity to tuberculin carry the higher risk of developing active TB . Accordi disease .Mtb antigens is not an indicative of resistance to the disease [Mtb antigens can be observed in patients suffering from HIV/AIDS or other forms of immunodeficiencies, but its underlying mechanisms in every subset of patients are not well-understood [Mtb antigens signifies the lack of TH1 type of antimycobacterial immune response, it can be associated with the unrestricted growth of the bacilli in any tissue/organ and the increased risk of mortality [It should be noted that even though the intensity of tuberculin reaction correlates with the risk of pulmonary TB, lack of reactivity or anergy to  disease . Anergy derstood . As anerortality . NeverthM. bovis-infected calves, which are natural hosts of these bacilli [M. bovis-specific T cells from these animals was also found to correlate with disease severity.The antimycobacterial immune response has been characterized in latent and active TB patients with an aim to understand underlying mechanisms of TB pathogenesis. These studies have shown that heightened levels of IFN-gamma are most invariably observed in lung tissue, bronchoalveolar lavage (BAL) fluid, pleural effusion, and lymph nodes of active TB patients . Interes bacilli . IFN-gamThe above findings are further corroborated by transcriptional profiling of immune response in active TB patients. Microarray analysis of whole blood cells by Berry et al. has revealed an increased transcription of IFN-gamma- and type I IFN-inducible genes in active TB patients, compared with latently infected people and healthy controls . AlthougMtb infection in otherwise healthy immunocompetent adults follows a definite pattern. Initial exposure to Mtb in these people is followed by an asymptomatic phase of infection called latent TB (LTB) [Mtb exposure and active disease in immunocompetent adults, which probably represents the time period required for host antimycobacterial immune response to accumulating and reach pathological intensity.TB (LTB) . AlthougTB (LTB) , 27. TheMtb re-exposure [Mtb-specific lymphocytes have been found to persist as memory cells for an extended period of time after successful chemotherapy [Mtb antigens is bound to result in a rapid and fully blown antimycobacterial immune response. If the weakened immune response were responsible for the pathogenesis of adult pulmonary TB, activation of memory cells would have conferred protection against active disease. However, pulmonary TB in immunocompetent adults being a manifestation of the hyperactive antimycobacterial immune response, cured TB patients are doomed to suffer again.A peculiar feature of adult pulmonary TB is that people who have been cured of active disease do not develop a resistance to subsequent infection. Instead, it has been observed that these people carry a significantly elevated risk of developing active disease with exposure . This asotherapy , 29. Re-+ T cells, offers a unique opportunity to understand the role of immune system in TB pathogenesis. It allows us to examine the effect of a weakened as well as a heightened immune response on the outcome of mycobacterial infection. Three possible outcomes of Mtb co-infection in HIV/AIDS patients are: (i) progressive primary TB (ii) progressive latent TB and (iii) immune reconstitution-induced TB (IR-TB).HIV/AIDS, which is characterized by reduced levels of CD4+ T cells in containing Mtb infection, the occurrence of a progressive primary TB in HIV/AIDS patients is conceivable. Progressive latent TB in HIV/AIDS patients is similar to progressive primary TB except that Mtb infection, in this case, is established before HIV-mediated immunosuppression. The unrestricted growth of bacilli in affected tissue(s) is responsible for disease symptoms in both progressive primary and progressive latent TB.Given the central importance of CD4Mtb-coinfected people treated with anti-retroviral therapy (ART) [Mtb infection.Immune reconstitution-induced TB (IR-TB), also known as tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS), is a special case of the disease observed in HIV- and py (ART) . It occupy (ART) . IR-TB apy (ART) . Interes+ T cell count. The presence of Mtb antigens at this stage results in the selective expansion of Mtb-specific CD4+ T cells [+ T cells with specificity to Mtb antigens are expanded in the co-infected people receiving ART [Mtb-coinfected people. Most importantly, it has been demonstrated that the co-infected people who develop IR-TB possess higher levels of circulating Mtb-specific CD4+ T cells, compared with those who did not experience this condition [+ T cell response against Mtb antigens.Administration of ART in HIV-infected people reduces viral load, leading to a rapid increase in CD4 T cells , 34. Stuving ART , 36. Conondition , 38. The+ T cells into M. avium-infected, T cell-deficient (TCRαKO) mice. It was observed that donor CD4+ T cells underwent a rapid expansion in M. avium-infected TCRαKO mice and led to the failure of lung function, wasting and eventual death. The authors further demonstrated that the ability to cause lung pathology was lost in IFN-gamma-deficient CD4+ T cells [+ T cells during Mtb infection.Mechanistic insights into IR-TB have been gained with a recently developed mouse model . In this T cells . Thus, sVitamin D is known to possess curative effects against TB since a long. Low serum level of vitamin D is an important risk factor for TB, and polymorphisms in both vitamin D receptor (VDR) and vitamin D-binding protein are associated with increased TB susceptibility , 41. WheH1 type of immune responses [H1 type of immune response can be partly attributed to IL-10 [+ FoxP3+ T regulatory cells (Tregs), which are the important source of IL-10 [Mtb infection has been shown to be associated with increased frequency of Tregs in lung tissue and bronchoalveolar lavage [Vitamin D dampens both innate and adaptive immune responses , 44. By esponses . Negativto IL-10 , 47. Intof IL-10 , 49. Ther lavage , 51.Mtb-infected animals [Similar to vitamin D, steroid and non-steroid anti-inflammatory drugs are known to possess ameliorating properties against TB. Corticosteroids are frequently used as an adjunct to standard therapy for treatment of various forms of TB and its associated complications, including IR-TB , 53. The animals .2 have been noted in sera of active TB patients, compared with healthy controls [The anti-inflammatory properties of steroids and NSAIDS have been implicated in their beneficial effects against TB. NSAIDs inhibit COX-1 and COX-2, and reduce biosynthesis of prostaglandins, which are involved in the cardinal signs of inflammation- redness, swelling and pain . Interescontrols . Corticocontrols . Supprescontrols .Mtb infection results in the increased resistance to active disease or in its better prognosis. Therefore, the pathological role of hyperactive immune response in adult pulmonary TB in immunocompetent hosts is corroborated by the curative effects of vitamin D and other anti-inflammatory agents against this disease.The beneficial of vitamin D and other anti-inflammatory agents against TB shows that controlling the host immune response during Mtb infection in humans. Active TB further manifests itself in different forms including primary TB in young children, disseminated TB in AIDS patients, reactivated TB in immunocompetent adults, and IR-TB in HIV-infected people receiving ART [Mtb.Our understanding of TB immunopathology has been complicated largely by the heterogeneity of this disease . Latent ving ART . Heterogving ART . DiffereMtb could be hypoactive, balanced or hyperactive. Upon initial exposure to Mtb, immunocompetent adults mount a balanced antimycobacterial immune response, resulting in containment of bacilli in lung granulomas and protection against active disease [Mtb immune response also takes place in AIDS patients receiving ART.The immune response against  disease . DependiMtb [The primary, disseminated and severe nature of TB in young children demonstrates the incompetence of their immune system to contain the bacilli. Interestingly, it has been observed that younger is a child, higher is the risk of TB. This pattern of disease occurrence in children suggests that resistance to TB develops with age (till adolescence) . AlthougMtb . SimilarMtb is shaped by multiple host factors, including age, diet, body mass index, genetic makeup, other chronic diseases or co-infections and exposure to environmental mycobacteria [Mtb infection may sometimes defy the generalizations in TB immunopathology. Owing to the unrestricted growth of the bacilli in immunodeficient hosts, Mtb infection in a certain proportion of these people can result in the pulmonary disease [It is noteworthy that outcome of the interaction between immune system and bacteria . Multi-f disease . Alterna+ T cell activity and IFN-gamma levels, is to blame for the pathogenesis of adult pulmonary TB in immunocompetent hosts. This evidence is provided by both observational and experimental studies on human subjects and contradicts the commonly held view that weakening of immune system leads to reactivation of latent Mtb infection into the active disease. Although the risk of TB is increased with the weakening of immune system, TB affecting the immunocompromised hosts is different from that occurring in immunocompetent adults. In immunocompromised hosts and young children, uncontrolled growth of the bacilli leads to the disease development, whereas in immunocompetent adults, immune system-mediated damage to lung tissue is to blame for the TB pathology. Different mechanisms of disease development are responsible for the heterogeneity of TB, which is being appreciated by an increasing number of researchers.The above evidence establishes that a hyperactive antimycobacterial immune response, characterized by heightened CD4Mtb immune response, without taking into consideration the heterogeneity of TB and its mechanisms of pathogenesis. Although such vaccines could be effective in the young children, as in the case of BCG, they are destined to fail in the immunocompetent adults.The view presented in this manuscript has a direct bearing on the course of TB vaccine development programs. Owing to the different mechanisms of pathogenesis, different vaccination approaches are required against different forms of TB. The antimycobacterial immunity needs to be boosted in young children and tamed in the immunocompetent adults. Unfortunately, the vaccinologists had been trying to boost the anti-Conclusively, if we wish to save another 100 years, billions of dollars, and most importantly, the millions of lives, it is high time to change our perspective of TB immunopathology. It is time to appreciate that TB is a heterogeneous disease and that different vaccination approaches are required to control its different forms. For TB continues to be a major public health threat with its drug-resistant form spreading at an alarmingly high rate, the onus of controlling the crisis lies with the immunologists.


Acute graft-versus-host disease (GvHD) is still a major cause of treatment-related mortality after allogeneic stem cell transplantation. Allo-antigen recognition of donor T cells after transplantation account for the onset and persistence of this disease. MicroRNAs (miRNAs) are molecular regulators involved in numerous processes during T-cell development, homeostasis, and activation. Thus, miRNAs also contribute to pathological T-cell function during GvHD. Given their capacity of fine-tuning T-cell function, miRNAs have emerged as promising therapeutic targets to curtail acute GvHD, but simultaneously maintain T-cell-mediated graft-versus-tumor effects. Here, we review the role of key miRNAs contributing to the pathophysiology of GvHD. We focus on those miRNAs acting in T cells and for which a role in GvHD has been established in preclinical models. Finally, we provide an outlook for clinical application of this new therapeutic target for GvHD prevention and treatment. Acute graft-versus-host disease (GvHD) is still a major complication after allogeneic hematopoietic stem cell or bone marrow transplantation . Allogeneic donor T cells are the main inducers of this too often lethal disease. Donor T cells recognize and respond to allo-antigen, use chemokine receptors and integrins to home to epithelial organs, such as the liver, the intestine, or the skin and orchestrate a significant immune response, which frequently results in severe organ damage. Unspecific prophylactic and therapeutic immunosuppressive treatment is the current clinical practice to improve patients’ outcome. However, the repertory of therapeutic and preventive options is limited and, therefore, new targets to control acute GvHD are urgently needed .via the T-cell receptor (TCR) in alloSCT, whereas central and/or memory T cells are not able to induce acute GvHD  effects  is a critical enzyme in providing essential amino acids for T cell proliferation and exerts immunosuppressive effects. Increased levels of IDO levels prevent acute GvHD . IDO is miR-181a acts as a rheostat for T cell sensitivity to antigen by downregulation of several phosphatases downstream of the TCR . Primaryvia a number of mRNA targets lacking corresponding miR-125b binding sites in mouse, including the genes encoding IFN-γ and IL-10RA (ex vivo. Recently, methods for efficient CRISPR/Cas9-mediated genome engineering of primary human T cells have been reported (in vivo (Understanding the role of miRNAs in physiological T cell function and in the context of disease has the potential to open up new avenues for therapy. Most of this knowledge is derived from the analysis of rodent models and is only beginning to be complemented by studies in human primary T cells . To a la IL-10RA . In termreported . In addi(in vivo , 96, som(in vivo , 69. In (in vivo .Our knowledge of miRNA action is far from complete and a number of miRNAs with a role in T cell function, for instance, miR-148a, miR-182, and miR-326, may ultimately also play a role in GvHD –100. Simex vivo and potentially even in vivo modulation. A better understanding of miRNAs controlling physiologic T-cell function has resulted in efficient translation of manipulation of miRNAs in preclinical models of GvHD. However, despite the generally broad interspecies conservation of miRNAs, translation into clinical treatment of GvHD remains a challenge.MicroRNAs play critical role in many biological processes including T-cell development and differentiation. Given that GvHD is a predominantly T-cell driven disease, miRNAs have emerged as attractive therapeutic targets for All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.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.


Information is lacking on prescribing of preventative cardiovascular pharmacotherapies for patients with non-ST elevation myocardial infarction (NSTEMI) in the Asian region. This study examined the prescribing rate of these pharmacotherapies, comparing NSTEMI to STEMI, and variations across demographics and clinical factors within the NSTEMI group in the multi-ethnic Malaysian population.n = 30,873). On-discharge pharmacotherapies examined were aspirin, ADP-antagonists, statins, ACE-inhibitors, angiotensin-II-receptor blockers, and beta-blockers. Multivariate logistic regression was used to calculate adjusted odds ratio of receiving individual pharmacotherapies according to patients’ characteristics in NSTEMI patients .This is a retrospective analysis of the Malaysian National Cardiovascular Disease Database-Acute Coronary Syndrome registry from year 2006 to 2013  in NSTEMI patients. More than 85% were prescribed statins and antiplatelets but rates remained significantly lower compared to STEMI. Women and those over 65 years old were less likely to be prescribed these pharmacotherapies compared to men and younger NSTEMI patients. Chinese and Indians were more likely to receive selected pharmacotherapies compared to Malays (main ethnicity). Geographical variations were observed; East Malaysian  patients were less likely to receive these compared to Western region of Malaysian Peninsular. Underprescribing in patients with risk factors such as diabetes were observed with other co-morbidities influencing prescribing selectively.This study uncovers demographic and clinical variations in cardiovascular pharmacotherapies prescribing for NSTEMI. Concerted efforts by policy makers, specialty societies, and physicians are required focusing on elderly, women, Malays, East Malaysians, and high-risk patients.The online version of this article (10.1007/s00228-018-2451-3) contains supplementary material, which is available to authorized users. Antiplatelets, beta-adrenoceptor blockers (beta-blockers), ACE inhibitors (ACEIs) or angiotensin-II-receptor blockers (ARBs), and statins are recommended as secondary preventative cardiovascular (CV) pharmacotherapies in post- acute myocardial infarction (AMI) patients by international clinical practice guidelines , 2. AlthMalaysia, a multi-ethnic, upper middle-income country in South-East Asia, provides a unique opportunity to study prescribing trends in this region of the world. Geographically, Malaysia is made up of two parts separated by the South China Sea; the Malaysian Peninsular  and the East of Malaysia on the northern part of Borneo  . The thrDespite embracing advances in management of cardiovascular (CV) disease, it remained the leading cause of mortality in Malaysia, accounting for 23% of all deaths . HoweverThis study was aimed to examine trends in the prescribing of on-discharge secondary preventative CV therapies for patients with AMI, comparing STEMI and NSTEMI in Malaysian population using the prospective National Cardiovascular Disease Database-Acute Coronary Syndrome (NCVD-ACS) registry. This study further focused on variations in prescribing for NSTEMI patients across age groups, gender, geographical regions, clinical risk factors and co-morbidities. This registry is part of the NCVD registry whereby 18 hospitals contributed data from patients with CV diseases from year 2006 till current. It is being sponsored by the National Heart Association of Malaysia (NHAM) and are continuously monitored to ensure quality. The registry included information on demographic information, CV diagnosis, co-morbidities, family history and in-hospital management and on-discharge medications. The details of the registry have been described in detail elsewhere . This dan = 30,873), both STEMI  and NSTEMI  were identified from the NCVD-ACS registry from year 2006 to year 2013. Variables extracted were gender, age, ethnicity, calendar year of visit, risk factors such as diabetes mellitus, hypertension, smoking status, family history of ischemic heart disease (IHD), previous history of IHD, and co-morbid conditions such as cerebrovascular disease, peripheral vascular disease (PVD), chronic kidney disease (CKD) and chronic lung disease. On-discharge CV medications included were antiplatelets (aspirin and adenosine diphosphate (ADP)-antagonists), ACEIs or ARBs, beta-blockers, and statins.Patients with AMI  and 95% confidence intervals (CI). Covariates chosen were those shown to impact prescribing trend such as age group, gender , ethnicip < 0.0001), beta-blockers (p = 0.001), and statins (p = 0.002) compared to STEMI (Supplementary Table p < 0.0001) were observed over the study period  (Table Older patients and women with NSTEMI were less likely to receive CV therapies (except beta-blockers) compared to younger patients and men Table . ChineseThere has been a significant increase in the prescribing of all CV therapies during the study period, with more than 85% of Malaysian patients with NSTEMI being prescribed aspirin and statins. The highest increase was observed with ADP-antagonists. NSTEMI patients were less likely to receive these medications compared to STEMI. Women and those ≥ 65 years old were less likely to receive CV therapies compared to men and younger NSTEMI patients. Significant variations were found across ethnicities and geographical regions. Risk factors such as diabetes and hypertension and co-morbidities such as cerebrovascular disease, CKD and chronic lung disease influenced CV prescribing for these patients.Improvement in prescribing rate is similarly observed in other countries , 25, 26 Like other population, women and the elderly were less likely to receive CV therapies compared to men and younger patients , 30. UndChinese and Indians were more likely to receive CV therapies compared to Malays as the main ethnicity. Different ethnicities may exhibit different clinical profiles, for example, Chinese had highest rate of hypertension and hyperlipidemia while Indians had higher rate of diabetes . InteresThose with NSTEMI were less likely to receive these medications compared to STEMI as physicians may favor more aggressive preventative therapies for STEMI . DiffereThis study uncovered variations in prescribing of evidence-based pharmacotherapies in NSTEMI patients using national CV registry. Recommendations for improvement should include establishment of hospital-based approaches such as medication checklists . InformaThis study utilized data from hospitals nationwide to represent unselected group of patients in a real-world setting. The inclusion of different spectrum of patients allows prescribing trends to be examined objectively. The database is well maintained, and training is provided regularly to ensure data quality. Some information is self-reported such as smoking status and past medical history and thus misclassification and under-reporting may occur. Information that measures socioeconomic status such as occupation and educational levels were not available. Ethnic minorities living in remote areas may have difficulty accessing health facilities and could have been under-represented. Participation of hospitals into this database is voluntary and thus there may be a selection bias and an overestimate of prescribing in the general Malaysian population. Many private hospitals did not participate in this registry and thus prescribing in this sector could not be determined.In conclusion, the prescribing of secondary preventative cardiovascular therapies for patients with NSTEMI had demonstrated significant improvement. This study uncovered demographical and clinical variations in the prescribing of cardiovascular therapies and hence concerted efforts by policy makers, specialty societies and physicians are required to overcome inequalities. Target population should include women, the elderly, Malay ethnicity, East Malaysians, diabetes, and CKD patients.ESM 1(DOCX 19 kb)


Additionally, the challenges and perspectives of SiNPs are also discussed. We prospect that the further development of these nanoparticles will lead to an exciting breakthrough in the understanding of biological processes.The need for novel design strategies for fluorescent nanomaterials to improve our understanding of biological activities at the molecular level is increasing rapidly. Dye-doped fluorescent silica nanoparticles (SiNPs) emerge with great potential for developing fluorescence imaging techniques as a novel and ideal platform for the monitoring of living cells and the whole body. Organic dye-containing fluorescent SiNPs exhibit many advantages: they have excellent biocompatibility, are non-toxic, highly hydrophilic, optically transparent, size-tunable and easily modified with various biomolecules. The outer silica shell matrix protects fluorophores from outside chemical reaction factors and provides a hydrophilic shell for the insoluble nanoparticles, which enhances the photo-stability and biocompatibility of the organic fluorescent dyes. Here, we give a summary of the synthesis, characteristics and applications of fluorescent SiNPs for non-invasive fluorescence bioimaging in live cells and  Recently, in vivo imaging technologies have attracted more attention for being effective to reveal how activities occur in the physiological state [Living cells and the human body are very complex systems because of the high diversity in organic composition and distinct temporal-spatial variation in metabolism. To properly understand life activities, we need to monitor the individual chemical interactions happening al state .in vivo [in vivo [Common traditional organic fluorescent dyes, such as, Cy3, fluorescein, 5-carboxyfluorescein (FAM), Cy5, carboxytetramethylrhodamine (TRAMA), fluorescein isothiocyanate (FITC) and Rhodamine B, are widely used reagents in bioimaging applications. However, there are still some defects, such as low fluorescence intensity, low photostability and insufficient stability, which make the traditional organic fluorophores not suitable for high-sensitivity detection and real-time monitoring. Increasingly studied in bioimaging, nanomaterials are a promising application prospect in vivo ,3,4,5. Fin vivo ,7. Among[in vivo . Moreove[in vivo . Because[in vivo . Further[in vivo . However[in vivo .After overcoming the above difficulties, we expect to achieve these as follows: small size to enter cells for bioimaging, high sensitivity for effective detection, fast response to monitor the life metabolism of targets, high abundancy, non-toxicity, good dispersibility in the biological environment, resistant to metabolic disintegration and photobleaching, high selectivity in the extremely complex organism ,13,14.etc.) to their surface, different fluorescent silica nanoparticles (SiNPs) have been widely used as an extremely significant platform to acquire more applicable bioimaging probes in living cells and the entire body [in vivo [With these properties, such as the excellent biocompatibility, non-toxicity, high hydrophily, optical transparency, tunable size and ease to covalently attach multifarious biomolecules  and amine (NH2) on their surface. SiNPs attach biomolecules effectively and can be easily modified with a variety of functional groups, such as poly(ethylene glycol) (PEG), hydroxyl (OH), carboxyl (COOH), phosphonate  and alkali as the catalyst. After removing the surfactant, the uniform pore structure can be formed. The synthesis procedure of MSN is shown as The common synthetic methods of SiNPs are the reverse micelle method and the Stöber method. Reverse microemulsion, one class of microemulsions, consists of a homogeneous transparent or translucent mixture of oil, water, an assistant of the surfactant and surfactant molecules that are isotropic and thermodynamically stable ,27,28. Se silica . In the e silica ,34. The e silica . MSNs wee silica ,37. One e silica . MCM-41 Due to the properties of the high efficiency, sensitivity and selectivity, organic fluorescent dyes have been widely used in bioimaging applications ,42,43,44et al. have successfully incorporated FITC into the silica matrix [Traditional fluorescent dye-doped SiNPs are used in the bioimaging field for the unique photo-stability, biocompatibility and easy modification of their surface. For example, Van Blaaderen a matrix . Tan anda matrix ,50. Recea matrix . MEF is a matrix ,53. Firsetc., via changing the amount of TEA used under the same conditions. The greater the amount of TEA used, the smaller the size. The cellular confocal laser scanning microscopy (CLSM) of MSNs-TAT with different sizes for 4-, 8- and 24-h incubations is shown in Recently, an aptamer-modified SiNPs system has also been reported . It is sN,N-phenylenebisdicarboxylic acid . Salphdc, a molecule with a unique autofluorescence characteristic and good biocompatibility, was used as a fluorescence imaging agent and gate-keeper for the metal-organic framework thin films interacting with metal ions [in vivo, both Dox@HPSN-Salphdc and Dox@HPSN-Salphdc-FA were injected into tumor-bearing mice. The whole-body real-time fluorescence imaging at different times, the fluorescence intensity of tumor after injection at each interval, the nanoparticle distribution in tissues and the fluorescence intensities of both nanoparticles in blood over time have been studied -conjugated pH-responsive SiNPs for targeted drug delivery and bioimaging have also been used by Cai’s group . The destal ions ,61. Moretal ions . To make studied .et al. recently synthesized multimodal imaging core-shell nanoparticles for the precision of tumor diagnosis using a single and simple injection of contrast agent [in vivo fluorescence imaging of four different SKOV-3 tumor (one kind of human ovarian tumor)-bearing mouse models has been performed. They also showed ex vivo fluorescence imaging to identify the organ distribution of the core-shell nanoparticles in xenografts. Moreover, in vivo and in vitro MRI have also been performed.Beside the single imaging modality, Piao st agent . The corst agent . To provin vivo, methylene blue (MB), one of the most extensively-used and inexpensive NIR fluorescent dyes, was selected to be doped into the SiNPs to construct a novel NIR fluorescence imaging system [et al. designed a multifunctional mesoporous SiNP platform for controlled drug release, targeted delivery and imaging in vivo [2-PEG-FA. After being modified with Cy5 via the 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride(EDC)/N-Hydroxysulfosuccinmide sodium salt (Sulfo-NHS) coupling method, the system MSN/COOH-PEG-FA is available for labelling. The electrostatic attraction between the Dox and nanoparticles is the main factor for the Dox loading. Considering the functionalization with negatively-charged carboxyl, we can load a large amount of Dox into the mesoporous SiNPs. Moreover, it is also found that the release of Dox from the MSN/COOH-PEG-FA nanosystems was related to the medium pH. The electrostatic interactions between the Dox and the carboxyl were decreased, while the electrostatic repulsion between them enhanced from pH 7.4 to pH 5.0. As the pH is lower in tumor cells than in normal cells, the delivery efficiency of the MSN/COOH-PEG-FA nanoparticles enhanced drastically. The imaging in mouse tumor after the injection of MSN/COOH-Cy5 and free Cy5 for different hours has been also investigated. Based on these characteristics, mesoporous SiNPs have the ability for both effective imaging and treatment of diseases.The signal of the conventional fluorescent dyes can be seriously affected by the autofluorescence from biological tissues, which always results in severe interference and limited penetration depth. To achieve a better imaging quality g system . Moreove in vivo . In thisTo solve the problem of background and interference between the emitting signals and the excitation light, Wang and co-workers presented a novel and ideal fluorescence resonance energy transfer (FRET)-mediated large Stokes shifting NIR fluorescent SiNPs (LSS-NFSiNPs) . FRET isin vivo MRI and NIR fluorescence imaging.A multimodal imaging SiNP probe labeled with NIR fluorescent dye has also been reported . Firstlyin vivo imaging, but also a nanocontrast for photoacoustic (PA)/NIR imaging dual-modality has been applied in noninvasive imaging [In vivo fluorescence imaging and photoacoustic imaging are carried out in their study.Not only have MRI/NIR and PET/NIR dual-modality been used for  imaging . They de1O2) [Two-photon fluorescent dyes can be another choice to realize deep-tissue imaging, since they can prolong observation time, provide low fluorescence backnd, less light scattering and less tissue injury and better three-dimensional spatial localization . Two-pho1O2) . With th2) for the detection of glutathione in water solution and in vivo [. The imaging of two-photon fluorescence for the detection of glutathione in CEM cells (human T cell acute lymphoblastic leukemia cell line) and tissues has been achieved  imaging experiment of glutathione in CEM cells demonstrated that the nanosensor can monitor the change of the glutathione in living cells (2 nanoparticles are available for effective imaging of glutathione in living cells and at the tissue level with high sensitivity and tissue penetration.In another application, Zhang and co-workers firstly reported a “turn-on” two-photon fluorescent dyes@MSN(TP-MSNs@MnO in vivo . The imaachieved . They usng cells . In addiin situ “turn-on” imaging of telomerase activity in vivo [In addition, different kinds of dye molecules can be capsulated inside one single SiNP simultaneously to construct large Stokes shifting fluorescence probes based on the principle of FRET, the ratiometric fluorescence platform and the fluorescence “turn on” nanosensor. A ratiometric pH nanoprobe was based on two-chromophore-doped SiNPs . These t in vivo . BHQ, imet al. also presented FRET-mediated NIR fluorescent dye molecule-doped fluorescent SiNPs, as we introduced above [ex vivo NIR fluorescence to investigate the distribution, they showed that FRET SiNP shave an application as a contrast for in vivo tumor imaging and cell tracking.Wang ed above . Moreoveed above . Tan anded above . They ched above . With siFluorescent imaging is a widely-used tool in biological research. The ever-increasing demand for monitoring multiple biological processes simultaneously calls for fluorescent probes that can meet many requirements, including, but not limited to, high stability and sensitivity in complex environments, good solubility and a proper emission spectrum. The unique characteristics, excellent biocompatibility, non-toxicity, high hydrophily, optically transparent, size-tunable and ease to covalently attach to multifarious biomolecules, have enabled SiNPs to construct fluorescent probes for effective imaging inside living cell and at the small animal level. Due to the robust and bright emitting light, fluorescent SiNPs have emerged as potential ﬂuorescent labels. Although enormous advances have been made using SiNPs in labeling, separation, bioimaging, disease diagnosis and therapy, several limitations hinder their further advancement. Firstly, the leakage of dyes from the fluorescent SiNPs over time, which could significantly shrink the fluorescence intensity of the particle and increase the background signal, needs further investigation. Secondly, the nonspecific binding of SiNPs needs to be settled. Thirdly, it is vital to standardize the procedure of the synthesis and functionalization to guarantee that SiNPs have a controllable size, good dispensability in aqueous solution and uniform multifunction. Moreover, to achieve ultrasensitive analysis, many fluorescent dye molecules need to be co-encapsulating inside one single SiNP. The multifunctional fluorescent SiNPs with the capabilities of diagnosis and therapeutics attract more attention, since they have great potential for providing an attractive see-and-treat strategy to deal with tumors or other diseases. However, SiNPs still have a very long way to translate the functionalized formulation systems into the medical market. We expect that SiNP-based nanoparticles can make significant progress and be applied in various clinical applications in the future.


Social status is an important predictor of parasite risk in vertebrates. To date, general frameworks to explain status-related variation in parasitism have remained elusive. In this meta-analysis, we evaluated five hypotheses proposed to explain status-related variation in parasitism in male and female vertebrates by leveraging variation in hierarchy type, mating system, parasite transmission mode, and allostatic load to test associated predictions. Our meta-analyses span 66 analyses (26 studies) of male vertebrates (two orders and five classes), and 62 analyses (13 studies) of female vertebrates (four vertebrate orders). Contrary to the prevailing paradigm that low status is linked to poor health, we found that dominant animals typically faced higher parasite risk than subordinates. This pattern was especially well-supported in analyses of males versus females, in linear versus egalitarian hierarchies, in mating systems where dominance rank predicts mating effort, and for contact- and environmentally-transmitted parasites rather than vector-borne parasites. These findings supported the priority-of-access and tradeoffs hypotheses suggesting that variation in parasitism is driven by rank-associated differences in exposure to parasites and mating effort. Together, these results suggest that high parasite risk might sometimes be an unappreciated cost of high rank, and conversely, reduced parasite risk might be a benefit of social subordination. In humans, low socioeconomic status is a leading predictor of chronic disease and reduced longevity4. In non-human animals, individuals at the bottom of a hierarchy often have to work harder for calories, receive less social support, and are subject to displacement and aggression from dominants1. As such, social subordination in mice, birds, and non-human primates is often linked to poor physical condition and a range of health problems, including hypertension, slow wound healing, inflammation, and poor immune responses7. However, whether social subordination also predicts patterns of parasitism remains an open question. This relationship is enigmatic, in part, because variation in parasite infection is driven, not only by differences in host susceptibility, but also by differences in parasite exposure. Here, we evaluate major hypotheses proposed to explain how host susceptibility and parasite exposure drive status-related differences in parasitism. To do so, we test predictions that rely on differences in host dominance structures and mating systems, as well as variation in parasite transmission mode.Social status can have profound consequences for vertebrate healthcondition-dependent hypothesis posits that status-related differences in physical condition lead to differences in parasite susceptibility and resistance9. If hierarchy position is linked to strong differences in physical quality, either because hierarchy position determines access to resources, or because an animal’s strength and physical condition determines their hierarchy position, animals that are stronger and healthier may rise to the top of the hierarchy, have the best access to resources, and therefore exhibit the lowest parasite burdens. In contrast, animals in poor condition may be restricted to the bottom of the hierarchy, have less access to resources, and be more susceptible to parasite infection. Second, the stress-response hypothesis proposes that the experience of low social status, including high rates of received aggression and unpredictable access to resources, can lead to chronic stress, which alters immune responses in ways that make low-status animals more susceptible to infection than high-status animals12. In support, studies have found that subordinate animals exhibit higher glucocorticoid levels than dominants, which can inhibit immune defenses against parasites13.To date, five hypotheses have been proposed to explain status-related variation in parasitism Table . Two of priority-of-access hypothesis proposes that dominant individuals have greater access to food15 and mates18, which in turn leads to higher rates of parasite exposure relative to subordinates20. In support, several studies have found that high-ranking individuals have higher mating success and the best access to nutritional resources and subsequently harbor more parasites than low-ranking individuals (e.g.22). Second, the tradeoffs hypothesis proposes that investment in reproductive effort by dominant individuals is negatively correlated with costly immune defenses, which increases susceptibility to parasites23. In support, several studies have found that the reproductive effort exerted by high-ranking males and females is associated with higher rates of parasitism compared to lower-ranking same-sex conspecifics (e.g.26). A variant of the tradeoffs hypothesis is the immunocompetence handicap hypothesis (ICHH), which posits that high-ranking individuals, typically males, maintain higher levels of androgens and parasitism than low-ranking individuals, which reflects an honest indicator of quality27. To date, the ICHH has yielded limited support29.In contrast to the stress-response and condition-dependent hypotheses, two hypotheses predict that high-ranking animals will be more parasitized than low-ranking animals. First, the allostatic load model integrates ideas from the tradeoffs, stress-response, and condition-dependent hypotheses30. The allostatic load hypothesis, which is adapted from previous work on humans31, posits that differences in allostatic load, defined as the cumulative physiological burdens exerted on the body to meet life history demands, predict status-related variation in parasitism. Within a species and sex, the rank that experiences the highest allostatic load is expected to exhibit the highest parasitism, and when ranks do not differ in allostatic load, there should be no status-associated differences in parasitism. Goymann and Wingfield32 found that the relative allostatic load of high- and low-ranking animals predicted their relative glucocorticoid levels. However, no studies have yet linked allostatic load to parasite risk in a meta-analytic framework.The 19. For instance, differences in the structure and form of animal hierarchies can influence susceptibility and exposure for both dominants and subordinates23. Specifically, in linear hierarchies . Conversely, in mating systems associated with subordinate social stress, high-ranking individuals are predicted to harbor fewer parasites than low-ranking individuals33. For example, in some polygynous mating systems , submissive males who are recipients of aggression harbor more parasites than dominants (e.g.33). Thus, variation in both hierarchy type and mating system might influence patterns of exposure, transmission, and susceptibility among high- and low-ranking conspecifics.It is unlikely that any single hypothesis explains status-related differences in parasitism across vertebrates. This is because variation in animal societies and parasite life histories can have important consequences for patterns of susceptibility, exposure, and transmission34. For instance, if high-ranking individuals have priority of access to mates or food, they may experience greater exposure to contact- and environmentally-transmitted parasites, but not parasites transmitted by flying-vectors, as compared to subordinates (e.g.22). However, if status-related differences in behavior drive differences in parasite susceptibility, for instance through nutritional limitation35, then low-status animals should be more susceptible to parasite infection, regardless of parasite transmission mode. Thus, rank-associated variation in parasitism is likely to be driven by the interplay between parasite transmission mode and host social behavior.Parasite transmission mode may also influence the link between host social status and parasite infection risk because differences in behavior between high- and low-status animals can create heterogeneities in parasite exposure32 and correlating these scores with parasite burdens: if relative allostatic load is correlated with relative parasitism, then this pattern would support the allostatic load hypothesis. Because general frameworks explaining the link between social status and parasitism have remained elusive, our results are an important step forward in understanding the primary drivers of status-related variation in parasitism.Our objective was to test leading hypotheses proposed to explain status-related differences in parasitism using multi-level meta-analytic models. We began by testing broad patterns of parasitism separately for each sex: if high-ranking males and females harbor more parasites than low-ranking same-sex conspecifics, then this pattern would support the tradeoffs and priority-of-access hypotheses. Alternatively, if low-ranking animals exhibit higher parasitism than high-ranking animals, this pattern would support the stress-response and condition-dependent hypotheses. Following these broad analyses, we tested specific predictions of each hypothesis in each sex based on variation in (i) types of dominance hierarchy, (ii) mating systems, and (iii) parasite transmission modes Tables –S2. FurtOur literature search yielded 26 studies and 66 distinct analyses for males and 13 studies and 62 distinct analyses for females. Seven taxonomic groups (two orders and five classes) were represented in analyses of males; four orders were represented in analyses of females Table . 91% n .2 = 99.19; 95% CI: 98.46–99.77), which indicates that the association between social status and parasitism is not uniform for all species. Furthermore, an Egger’s test revealed significant publication bias: the trim and fill method estimated that there was one fewer published analysis than expected with a small sample size and where subordinates had higher parasitism than dominants  in 41 of 66 analyses (62.1%), negative effect sizes in 22 analyses (33.3%), and an effect size of zero in three analyses (4.5%). This pattern persisted when we analyzed each measure of parasitism separately Table : high-ra20. In support, high-ranking males in linear despotic hierarchies exhibited higher parasitism than low-ranking males , while social status did not predict male parasitism in the one study of an egalitarian species . Further, we found that dominant males had higher burdens of environmentally- and contact-transmitted parasites  than subordinate males, but dominance rank did not predict differences in infection risk for parasites transmitted by flying-vectors . For the above analyses, study setting did not significantly improve model fit, and was subsequently removed from our final models  in linear but not egalitarian hierarchies, and (ii) for contact- and environmentally-transmitted parasites but not vector-borne parasitess Tables .23. In support, high-status males in hierarchies and mating systems associated with high mating effort harbored significantly greater parasites than low-status males , but not in mating systems and dominance hierarchies where social status is not a strong predictor of mating effort brms package are 2-tailed36 while the p-values are 1-tailed). Similar to males, we found high levels of total heterogeneity in our best supported model , again indicating that the association between social status and parasitism is not uniform for all species. Unlike the male studies, we did not observe evidence of publication bias in female studies . There were no consistent rank-associated differences in parasitism for the remaining clades , negative effect sizes in 20 analyses (32.3%), and an effect size of zero in six analyses (9.7%). In sub-analyses for each parasitological measure Table , we founes Table .We found limited support for the priority-of-access hypothesis in analyses of females. While our data did not include any females living in egalitarian societies, we were able to test status-related differences in parasitism for females in linear hierarchies. Contrary to the priority-of-access hypothesis, there were no status-related differences in parasitism for either age-based or nepotistic linear hierarchies . Likewise, across 48 available female analyses, there was no significant correlation between relative allostatic load and relative parasitism .12. However, whether social subordination also predicts infectious disease risk, has remained an open question. Overall, our meta-analyses revealed that individuals at the top of the hierarchy, rather than subordinates, often bear the highest parasite burdens. This pattern was most evident in male mammals, in linear hierarchies, in mating systems where rank predicts mating effort, and for contact- and environmentally-transmitted parasites. Of the five models evaluated, we found general support for the priority-of-access and tradeoffs hypotheses, both of which predict higher parasitism in high-ranking individuals, but little or no support for the condition-dependent, stress-response, or allostatic load hypotheses. Together, these results suggest that social subordination is not always bad for health, and parasite risk is sometimes an underappreciated cost of high dominance rank.A dominant paradigm in the scientific literature has been that subordinate social status is linked to poorer health and immunity23. In support of the first driver, several studies have found a link between social status, access to resources, and parasitism (e.g.22). For example, dominant, territorial male occelated wrasses (Symphodus ocellatus), a common Mediterranean fish species, have priority of access to apparent parasite-rich breeding territories, and because they remain sedentary to defend their territories, exhibit higher prevalence of infection of the trematode worm, Genitocotyle mediterranea, than subordinate, non-territorial conspecifics38. Likewise, dominant reindeer (Elaphostrongylus rangiferi) consume more vegetation and consequently harbor more nematodes than subordinates21. Rank-associated differences in priority of access to mates can also lead to differences in parasite risk (e.g.18). For example, dominant male feral cats (Felis catus) have preferential access to females, and typically have higher incidence of feline immunodeficiency virus than subordinates16. The second driver, greater parasite susceptibility due to status-associated differences in mating effort, is based on the idea that, rather than investing in costly immune responses, high-ranking males, and sometimes females, allocate energy towards rank acquisition and mating effort, which in turn, increases susceptibility to parasitism23. In support, numerous studies have found tradeoffs between reproductive effort and immunity41. For instance, dominant male superb fairy wrens  exhibit iridescent blue plumage coloration and have higher testosterone levels than lower-ranking, duller males42. They also harbor significantly more blood-borne parasites than their subordinate counterparts43. Likewise, dominant, cooperatively breeding female meerkats exert greater mating effort than subordinate same-sex conspecifics, and this behavior is positively correlated with parasitism26. Thus, the behaviors of high-ranking individuals, namely outcompeting conspecifics for access to food, water, and social partners, and the exertion of mating effort, appear to be important divers of rank-associated differences in parasitism.Given the support we found for the priority-of-access and tradeoffs hypotheses, we propose that rank-associated differences in parasitism are likely explained by two key drivers: (i) greater exposure to parasites in high-ranking compared to low-ranking hosts due to status-associated differences in access to resources; and (ii) greater susceptibility to parasitism in high-ranking compared to low-ranking hosts due to status-associated differences in mating effort44. This theory is predicated on the idea that male fitness is limited by the number of receptive females and that female fitness is limited by offspring production45. Thus, females are expected to invest more in immune defense to promote longevity and offspring survival, whereas males should exert effort towards intrasexual competition at the expense of immune defense44. In agreement, males tend to have weaker immunity than females and suffer disproportionately from parasitism and disease47. These differences may be mediated by rank-driven, testosterone-induced immunosuppression48 (but see29), or alternatively, by sex-related differences in immunosuppressive stress hormones49. Additionally, rank-related differences in reproductive effort are probably weaker in females than males44; hence tradeoffs between reproductive effort and defense against parasites might not be as strong in females. For example, contrary to the predictions of the tradeoffs hypothesis, there were no significant rank-related differences among females in nepotistic or age-based linear hierarchies. Because rank relationships in nepotistic and age-based hierarchies tend to be stable across generations51, perhaps we should not expect to observe the same results as we found in male despotic hierarchies, where individuals need to fight to attain and maintain dominance rank (e.g.52). Lastly, in terms of priority of access to resources, in many mammalian societies, males outrank females2, thus high female rank doesn’t necessarily translate to high access to resources. For example, in chimpanzees, nearly all males outrank females, and skew in rank differences predicts whether food resources are transferred from low-ranking to high-ranking conspecifics53. In females, we found only partial support for the priority-of-access hypothesis, supporting the idea that differences in parasite exposure between high- and low-ranking conspecifics might be more prominent in one sex than the other.However, this overall pattern – higher parasitism in higher-ranking individuals – was more pronounced in analyses of males than females. Across male studies, high-ranking individuals harbored significantly more parasites than low-ranking individuals, while in females; this pattern was just a trend. These results suggest that key differences between the sexes in immunity, life history strategies, and behavior may interact with status-related differences in parasite exposure and susceptibility to create sex differences in status-related parasite risk. In support, the sex-related differences in status-based parasitism that we found are consistent with life history theory, which predicts that females will invest more in immune defense than males12. Classic studies of rodents55, non-human primates57, and humans58 have established a link between social subordination and hypercortisolism, inflammation, and chronic disease risk. Contrary to these patterns, our analyses of social status and parasitism did not support the stress-response, condition-dependent, or allostatic load hypotheses. Thus, rank-associated patterns of parasitism may differ from rank-associated patterns of many measures of health and immunity raising the question: why is parasitism different from other measures of health?The links between subordinate social status, allostatic load, and poor health are well-supported in the literature3. Antibodies are Th-2 mediated and a primary mechanism for fighting extracellular parasites59. Thus, the stronger response in low-ranking males might be indicative of resistance to gastrointestinal helminth infections60. In the same study3, dominant males exhibited significantly stronger delayed-type hypersensitivity reactions than subordinates, reflecting Th-1 mediated immunity and defense against intracellular parasites61. Because Th-1 responses can down-regulate Th-2 responses and vice versa59, subordinates may have stronger immune defenses against extracellular parasites than dominants. Indeed, the down-regulation of Th-2 mediated defenses in dominant individuals to increase mating effort is consistent with the tradeoffs hypothesis20. Alternatively, low-ranking males might be less stressed or in better condition than hypothesized49, which may explain why we did not find support for the stress-response or condition-dependent hypotheses. A recent review of social status and glucocorticoid levels across male and female vertebrates yielded mixed results, with the majority of studies reporting no significant differences in levels of stress hormones between high- and low-ranking conspecifics7. Similarly, in cooperative breeders, only one of 12 species exhibited higher glucocorticoids in subordinates than dominants13, indicating that chronic stress is not consistently associated with subordinate social status.One explanation for why rank-associated patterns of parasitism might differ from rank-associated differences in health is that subordinate social stress does not alter immune responses relevant to parasite risk. A recent meta-analysis of social status and immune response found that subordinate males exhibited stronger antibody responses to antigens than dominants62 . Subordinate animals in captivity, unlike those in the wild, are incapable of avoiding dominant individuals, and may experience considerable chronic stress stemming from higher rates of received physical and psychological aggression than in the wild13. For example, dominant wolves (Canis lupus) exhibit higher levels of stress hormones in the wild63, whereas subordinates are more stressed in captivity64, suggesting that susceptibility to parasitism might differ based on study setting. While recent studies of captive animals have reported a link between subordinate social status and immunosuppression (e.g.55), whether such patterns persist in natural settings remains an open question. Indeed, a number of studies have reported differences in immune response in captive versus wild animals again suggesting that study setting matters (e.g.67). In the present study, the inclusion of study setting rarely improved model fit. This might be due to the paucity of captive studies. For example, over 90% of the male analyses occurred in wild settings with no provisioning, while the remainder occurred in captivity. Further, although female study settings included both non-provisioned (66%) and provisioned (32%) wild populations, only one analysis (2%) occurred in captivity. Thus, the lack of captive studies on social status and parasitism might explain why study setting did not significantly improve model fit for most of our analyses.An alternate explanation for why patterns of parasitism are different than patterns of chronic disease risk is that many studies testing the relationship between social status and immunity occur in captive settings, and hierarchies in captivity may differ in important ways from hierarchies in the wild32 found a significant correlation between relative allostatic load and relative cortisol, a marker of chronic stress. In our study, we replaced relative cortisol with relative parasitism, but we found no correlation between relative parasitism and relative allostatic load. Our results suggest the possibility that relative allostatic load plays a less palpable role in modulating parasitism than it does in modulating stress. If so, our results refute an established paradigm – the idea that the accumulation of physiological burdens decreases immune defense and increases susceptibility to parasitism49. Alternatively, there might be limitations in the metric used to quantify allostatic load32 as it is largely qualitative. Protocols for measuring allostatic load quantitatively have been well-established for assessing human subjects31. Analogous protocols for assessing allostatic load in free-ranging vertebrates that are uniform, practical, and measurable would be an important step for solving this problem.We found that relative allostatic load was not correlated with relative parasitism. This result was interesting and somewhat surprising because the allostatic load model integrates ideas from the other hypotheses proposed in this study – i.e. the costs of attaining and maintaining dominance rank (tradeoffs hypothesis), the costs of subordinate social status (stress response hypothesis), and differential access to resources (condition-dependent hypothesis). A well-cited study by Goymann and WingfieldOur findings suggest several important areas of subsequent investigation. First, we recommend that researchers work to increase the taxonomic diversity of both vertebrates and parasites in future studies. While we identified many studies that compared social status and parasitism in male and female vertebrates, like most meta-analyses, we were limited by the available data, and some taxonomic groups were better represented than others. Studies of egalitarian hierarchies, monogamous mating systems, and vector-borne parasites were relatively uncommon. Thus, diverse mating systems, hierarchy types, and parasite transmission modes are needed to better distinguish competing hypotheses. Moreover, most of the parasites included in our analyses consisted of helminths and other eukaryotic parasites. Thus, an important area for future work will be to test these hypotheses for non-eukaryote parasites (i.e. viruses and bacteria).Nanger granti)68. First, Ezenwa22 completed two steps to evaluate the priority-of-access hypothesis: (i) quantifying the density of parasites in the habitats of dominant, territorial Grant’s gazelle males and the density of parasites in the habitats of subordinate, non-territorial, males, and (ii) comparing rates of parasitism in dominants versus subordinates. This approach was especially useful because it not only quantified differences in parasitism between dominants and subordinates, but also established actual rank-related differences in exposure. Second, more recently, Ezenwa and colleagues68 used multiple measurements to assess a variant of the tradeoffs hypothesis (i.e. ICHH), which included measures of parasitism, horn size (a proxy for condition), testosterone, social status, and quantification of innate and adaptive immune responses. Thus, as illustrated by the above examples, future research needs to move beyond the simple assessment of social status and parasitism, to experimental work and study designs that incorporate comprehensive approaches for distinguishing alternative hypotheses to explain status-related variation in parasitism.To better distinguish competing hypotheses, we also recommend that future studies of social status and parasitism expand the battery of tests applied to individual species. Two examples of this approach have been applied in Grant’s gazelles . For both search engines, in the advanced settings, we set the timespan from 1900–2016 and allowed all languages. We used the basic search function (topic in Web of Science) and all possible combinations of the following two sets of search terms: (i) social status; social domin*; social hierarchy; rank, and (ii) parasit*; disease. We also examined the reference lists in each study to identify studies not found in the databases. We included studies that compared the association between social status and parasitism in adult male and/or female vertebrates, and that reported effect sizes and sample sizes. Some authors only reported effect sizes  for their significant results, but did not report effect sizes for their non-significant results. In these and other cases where sample sizes or effect sizes were not reported, we attempted to obtain these data in three ways: (i) by contacting the study authors via email, (ii) extracting effects sizes from figures using WebPlotDigitzer 2.070, and (iii) calculating effect sizes using data published in online repositories . We included studies that occurred in natural, provisioned, or captive settings. We excluded analyses that did not directly compare dominants to subordinates, studies of juveniles, and studies of castrated males. For the purposes of this study, we used the following conceptual definition of social status: any dominance relationship in which one individual is consistently outcompeted by another in a dyadic agonistic interaction71. For clarity, the terms (i) high-ranking and dominant and (ii) low-ranking and subordinate were used interchangeably3.We searched for published studies that compared social status and parasitism in male and female vertebrates using ISI Web of Science and Google Scholar. We followed the protocols for Preferred Reporting in Systematic Reviews and Meta-Analyses (PRISMA)We extracted the following information from each study: (i) study species, (ii) study setting as captive  or wild (provisioned or non-provisioned), (iii) the method of measuring dominance rank Table , (iv) th32. To do so, we directly contacted the authors of each study  and adjusted node ages for published divergence times using BLADJ in Phylocom 4.274.To control for phylogenetic signal, we constructed two separate phylogenies based on relationships in the Tree of Life for the 21 male  and ten female host species  included in our meta-analysesre Table . We buil75 to convert means and standard errors, means and standard deviations, and other statistical measures into a standardized mean difference, Cohen’s d. We evaluated significance by determining the 95% confidence intervals surrounding d. Negative values indicated studies in which dominant individuals exhibited lower parasitism than subordinates. Positive values reflected studies in which subordinate individuals exhibited lower parasitism than dominants.To test the association between social status and parasitism, we applied a meta-analytic approach. Males and females were analyzed separately. For each analysis, we designated subordinates as the control, and assigned dominants as the treatment. In some studies, researchers divided animals into two distinct groups – those who were high-ranking and those who were low-ranking as defined by the study, and then reported the mean and standard error or mean and standard deviation for both groups. In other studies, the researchers assigned each individual an ordinal rank, and then correlated ordinal rank with parasitism. In these and other cases, we used an effect size calculatorbrms package36 in R. Because of the multifactorial nature of drivers of parasitism, we used multi-level models, which included three random effects: (i) study identity, to control for non-independence among data points from the same study; (ii) species, to account for non-phylogenetic variation among species; and (iii) phylogeny, to account for phylogenetic relatedness among species. We incorporated effect size weights by linking the sampling variances with their estimated effect sizes using the se function within each model’s response term36. The model with the lowest k-fold information criterion (kfoldIC) was selected after performing k-fold cross validation in the brms package, with k equal to the maximum of ten or n (number of effect sizes)36. We included study setting as a fixed effect in all analyses where doing so improved statistical support for the model, based on k-fold cross validation. When study setting did not improve the model, we excluded this moderator from the final analysis. For males, there were no studies that occurred in wild settings with provisioning; therefore, we only included wild (without provisioning) and captive studies as fixed effects. For females, we included wild (with and without provisioning) and captive studies as fixed effects. For all models, we specified non-informative normal priors (µ = 0 and σ = 10) for the fixed effects and non-informative Student’s t priors  for the random-effects. For each model, four chains were run in parallel for at least 4000 iterations, with a warm-up period of at least 1000 iterations; convergence was confirmed with Gelman–Rubin diagnostics76, showing all potential scale reduction factors < 1.1. For each model, we report the effect size (intercept) as posterior mean, two-tailed 95% credible interval (CI), and one-tailed percent of posterior samples (p) less than zero for a positive mean effect size or greater than zero for a negative mean effect size. We quantified total heterogeneity using the I2 statistic78. We tested for publication bias using both visual (funnel plot) and quantitative (Egger’s test) assessments80. When an Egger’s test revealed significant publication bias, we used the trim and fill method to estimate the number of missing studies80.We performed phylogenetic meta-analyses using the Papio; (iii) Papio + Mandrillus + Macaca; and (iv) Primates. To examine variation based on the metric used to measure parasitism, we conducted analyses (separately for each sex) on subsets of parasitological measures. Specifically, we tested the association between social status and (i) richness; (ii) intensity; and (iii) prevalence.To examine clade-specific variation in status-based parasitism, we performed meta-analyses on subsets of the phylogenetic tree. Specifically, we evaluated the following taxa for males: (i) Aves; (ii) Carnivora + Artiodactyla + Perissodactyla; (iii) Cercopithecidae; (iv) Diapsida; (v) Mammalia; (vi) Primates; and (vii) Squamata. We evaluated the following taxa for females: (i) Carnivora + Artiodactyla + Perissodactyla; (ii) brms package36. For these sub-analyses, we conducted meta-analyses for sample sizes of six or more, and pruned each phylogenetic tree accordingly.We tested predictions of the tradeoffs, stress-response, priority-of-access, and condition-dependent hypotheses by comparing status-related variation based on hierarchy type, mating system, and parasite transmission mode. As before, we incorporated multi-level meta-analytic models and tests for significance in the To test the allostatic load hypothesis, we applied Pearson product-moment correlations to compare relative allostatic load to relative parasitism. Relative parasitism was calculated by dividing mean parasitism in dominants by mean parasitism in subordinates for studies where these data were available. Relative allostatic load was calculated by dividing dominant allostatic load by subordinate allostatic load. As in prior analyses, males and females were assessed separately.https://github.com/mdoellma/social_status_parasitism_meta_analysis.Analyses reported in this article can be reproduced using the sample code provided in the supplement . Data used for meta-analyses is available in the supplement, and has been uploaded to the Github repository: Supplementary MaterialsSupplementary Code


To investigate the relationship between brain natriuretic peptide andrecurrence of atrial fibrillation after successful electricalcardioversion.Medline and Embase databases were used to identify publications evaluatingBNP/N-Terminal (NT)-proBNP levels in association with atrial fibrillationrecurrence after successful electrical cardioversion. Nineteen studies thatfulfilled the specified criteria of our analysis were found.Baseline BNP/NT-proBNP levels of the atrial fibrillation recurrence groupwere significantly higher than those of the sinus rhythm maintaining group.Our analysis suggests that low BNP/NT-proBNP levels are associated with sinusrhythm maintenance, and baseline BNP/NT-proBNP concentrations may be apredictor of atrial fibrillation recurrence after successful electricalcardioversion. There are manypredictors of SR after cardioversion of AF, of which BNP/NT-proBNP is a commonlydescribed one.Atrial fibrillation (AF), the most prevalent cardiac arrhythmia, is a costly diseaseassociated with significant morbidity and mortality. There are two modalities oftreatment for AF: rate control and rhythm control. Rhythm control is preferred incases in which sinus rhythm (SR) is expected to be maintained after cardioversion.Direct-current cardioversion is frequently used to restore SR in patients with AF,but the recurrence rate of AF after direct-current cardioversion is 50% after sixmonths, which included 10 trials and 618 patients,concluded that higher plasma BNP levels are associated with a greater risk of AFrecurrence. Since 2011, nine additional randomized controlled trials were publishedwith double the sample size and that contained information on the associationbetween BNP/NT-proBNP and AF recurrence.Evidence from several studies supports the relationship between BNP/NT-proBNP and AFrecurrence before electrical cardioversion, but other studies have failed to find anassociation. In 2011, a meta-analysis by Tang et al.Under this circumstance, this updated meta-analysis was conducted to reveal a wealthof evidence and provide more valid information for clinical practice.. Medline and Embase databases were used to identifyrelevant publications indexed between January 1980 and August 2016, using thefollowing key words ["natriuretic peptide" and "atrial fibrillation"] or["atrial fibrillation" and "cardioversion"] or ["atrial fibrillation" and"electrical cardioversion"]. We reviewed abstracts except for articles thatfocused on natriuretic peptide in AF cardioversion, for which we obtained fulltext. A review for the references of identified studies was conducted andlimited the language to English. The corresponding authors were contacted iffurther unpublished data were needed. And a manual search was also conducted forrelevant review articles and for abstracts of the scientific sessions of theAmerican College of Cardiology, the American Heart Association and the EuropeanSociety of Cardiology for the past five years.This analysis was performed according to the guideline of the Meta-analysis ofObservational Studies in Epidemiology Group.Studies were considered eligible for inclusion in our meta-analysis if they meetthe following criteria: (i) they were observational studies; (ii) they evaluatedthe potential relationship between plasma BNP/NT-proBNP levels beforecardioversion and AF recurrence after successful electrical cardioversion; (iii)they used AF recurrence rates as an index of the outcome; and (iv) they used afollow-up period of ≥ 5 days. The 5-day follow-up was decided on thebasis of the 2010 European Society of Cardiology guidelines, which indicate alate recurrence of AF that occurs more than five days after successfulelectrical cardioversioni.e.,withdrawal rate was <20%); (iv) whether confounding and predicting factorswere distinguished; and (v) whether there was a clear description of thedetection system used to identify the incident endpoint.To examine biases in the studies and their effects, quality assessments accordingto the following criteria were conducted: (i) whether the inclusion criteria andthe end of the event were clearly defined; (ii) whether the follow-up period wasadequate; (iii) whether all cases were followed up , AF duration, follow-up period), AFdetection methods, number of AF recurrence and SR-maintaining patients, and meanand standard deviation (SD) of BNP/NT-proBNP concentrations in the AF recurrenceand SR-maintaining groups. If the documents provided medians and range, themethod of Hozo et al. wasused to calculate the mean and SD.Two reviewers independently extracted data from each study. Results werecompared, and any disagreements were resolved by consensus. The extracted dataincluded first author, patient characteristics /Q. I2 is an intuitive andsimple expression of the inconsistency in studies' results. We considered anI2 statistic of 50% or more as indicative of a considerable levelof heterogeneity; if I2 >50%, the random effects model wasused. Otherwise, thefixed effect model was used. We planned to perform sensitivity analysis andsubgroup analysis to explore the potential influence of heterogeneity.Data were collected and analyzed using STATA software . Cochrane's Q test is the most commonly used method toevaluate heterogeneity. In our article, the result of this test is shown byI-25. A total of 1,373 patientswere enrolled in these studies: 657 cases were classified in the AF recurrencegroup and 716 in the SR-maintaining group. Basic characteristics of the 19studies are shown in Our initial literature search identified 1,064 studies , of whicFindings from the meta-analysis related to the relationship between plasmaBNP/NT-proBNP level and AF recurrence after successful electrical cardioversionin patients with AF are shown in P<0.0001;I2=92.8%). We analyzed the heterogeneity using the random effectsmodel. To explore potential reasons for heterogeneity, we conducted a subgroupanalysis to investigate the effect of follow-up duration on BNP/NT-proBNP levelsbetween the SR and AF groups, because the duration of the follow-up period was amajor difference in the included studies. This subgroup analysis showed in thelong-term follow-up subgroup (defined as followup >1 month)  and the short-term follow-up subgroup , baseline BNP/NT-proBNP levelsin the AF recurrence group were significantly higher than BNP/NT-proBNP levelsin the SR-maintaining group . The heterogeneity was observed in our analysis, which may beattributed to differences in patient characteristics, such as etiology, AFduration, age, and heart function. Possible language and publication biases mayalso be considered. Distribution of data points on a funnel plot (Begg test)indicated that bias were possibly related to language and publication bias(When the study with the shortest follow-upion bias. was conducted. In contrast to theirmeta-analysis, we pooled the BNP/NT-proBNP results. Moreover, the studies involvingboth electrical cardioversion and pharmacologic cardioversion were excluded.Our meta-analysis aimed to further explore the relationship between BNP/NT-proBNPlevels before successful electrical cardioversion in patients who maintained SR andwho had AF recurrence during the follow-up period. The result of our analysis showedthat patients with lower BNP/NT-proBNP concentrations were more likely to remain inSR after successful electrical cardioversion. This analysis was conducted in 2011,when 10 studies were included in our analysis. Our present analysis contains nineadditional studies, including studies with negative results and twice the number ofpatients. A previous meta-analysis by Zografos et al. studied atrial BNP geneexpression in patients with paroxysmal and persistent AF and found that the atriumwas the major site of BNP gene expression. Silvet et al. found that the increase in BNP levels afteratrial stretching and volume overload was closely related to chronic AF. Inaddition, pathologic changes such as the enlargement and fibrosis of the atrium mayalso cause increased BNP. BNPlevels may also reflect a higher degree of systematic inflammation, which isconsistently associated with AF. The question of whether BNP/NT-proBNP can be used as aneffective indicator in the proactive prevention of AF or its recurrence or in thelikelihood of success of cardioversion treatment has, therefore, attracted wideattention.B-type natriuretic peptide, a neurohormone, is synthesized as a prohormone in theheart in response to increased myocardial wall stress from volume or pressureloading and other factors. The peptide proBNP is cleaved into BNP and thebiologically inactive fragment NT-proBNP. BNP is secreted primarily by ventricularmyocytes. In the patients in our analysis, which mainly have preserved ejectionfraction, high BNP/NT-proBNP level may have occurred for a different reason. Inpatients with AF, there is evidence that BNP is secreted by the atrium. Tuinenburget al.-25 showed that after successful electrical cardioversion, AF wasmore likely to recur in patients with high, rather than low, plasma BNP/NT-proBNPconcentrations. This indicates that plasma BNP/NT-proBNP level is a predictor of AFrecurrence. Our subgroup analysis achieved the same result, regardless of the long-and short-term follow-up period, which indicated that the baseline BNP/NT-proBNPconcentrations may be a predictor of AF recurrence after successful electricalcardioversion. Distribution of data points on the funnel plot graph afterapplication of the random effects model indicated possible language and publicationbiases.The present updated meta-analysis of 19 AF-related publications. The measurement of plasmaBNP/NT-proBNP levels may help predict the risk of AF recurrence, thus helping theinitial selection of suitable patients for AF treatment.As a biomarker indicator, plasma BNP/NT-proBNP level has the advantages of cost-effectiveness, convenience, and a high degree of reliabilityOur analysis suggests that low BNP/NT-proBNP levels are associated with SRmaintenance, which is consistent with our previous finding even after including nineadditional studies and doubling the number of patients. Even though usingBNP/NT-proBNP levels could not guide electrical cardioversion by current evidence,our work's purpose is to suggest that BNP/NT-proBNP levels may help predict the riskof AF recurrence, thus helping the initial selection of suitable patients forelectrical cardioversion; therefore, further research is needed to explore such acutoff of BNP/NT-proBNP value to select the right patients for electricalcardioversion.A limitation of this study is the significant heterogeneity, which probablyreflects several differences between the included studies, such as patientcharacteristics. Nevertheless, we failed to observe a significant differencebetween studies with short- long-term follow-up. Another potential factorcontributing to the observed heterogeneity is the difference in patientcharacteristics, such as etiology and ejection fraction. We included patientswith AF with varying etiology; details of the etiology were not alwaysavailable, even though the majority of studies included patients with preservedLV systolic function, and details on diastolic or left atrial function were notalways available. Differences in these variables may account for the observedbetween-study differences as well as the significant in-study variation, whichis evident in the wide SD of BNP or NT-proBNP levels observed in manystudies.