Sex bias in trials and treatment must end

Ectonucleoside Triphosphate Diphosphohydrolase-1/CD39 Affects the Response to ADP of Female Rat Platelets

There is evidence that an imbalance of extracellular purine levels may be associated with increased cardiovascular risk. Platelets play a pivotal role in vascular homeostasis and thrombosis and are important source of purine nucleotides and nucleosides. Hydrolysis of nucleotides ATP and ADP is regulated by two ectonucleotidases, triphosphate diphosphohydrolase-1 (NTPDase-1/CD39) and ecto-5’-nucleotidase (ecto-5’-NT/CD73). CD39 enzyme is expressed on the endothelium, circulating blood cells, and smooth muscle cells; there is evidence that changes in CD39 expression and activity affects the potential thrombogenic of a tissue. Gender difference in the cardiovascular risk has been extensively observed; however, while the age-dependent difference in the prevalence of cardiovascular events between men and women has been attributed to the loss of the protective effect of estrogens in the postmenopausal period, the physiological mechanism behind gender disparity is still unclear. Here, we evaluated comparatively male and female rat platelet reactivity and considered the possible role of CD39 at the basis of difference observed. We found a reduced in vitro response to ADP (1–30 µM) of female compared to male platelets, associated to increased platelet CD39 expression and activity. Platelet response to ADP was strongly increased by incubation (10 min) with the CD39 inhibitor, ARL67156 (100 µM), while male platelet response was unaffected. Rat treatment with clopidogrel (30 mg/kg, per os) inhibited ex vivo platelet aggregation. Bleeding time was prolonged in female compared to male. Taken together, our results suggest that platelet ATPase and ADPase activity might be a reliable predictor of platelet reactivity.

"Bridging the Gap" Everything that Could Have Been Avoided If We Had Applied Gender Medicine, Pharmacogenetics and Personalized Medicine in the Gender-Omics and Sex-Omics Era

Gender medicine is the first step of personalized medicine and patient-centred care, an essential development to achieve the standard goal of a holistic approach to patients and diseases. By addressing the interrelation and integration of biological markers (i.e., sex) with indicators of psychological/cultural behaviour (i.e., gender), gender medicine represents the crucial assumption for achieving the personalized health-care required in the third millennium. However, ‘sex’ and ‘gender’ are often misused as synonyms, leading to frequent misunderstandings in those who are not deeply involved in the field. Overall, we have to face the evidence that biological, genetic, epigenetic, psycho-social, cultural, and environmental factors mutually interact in defining sex/gender differences, and at the same time in establishing potential unwanted sex/gender disparities. Prioritizing the role of sex/gender in physiological and pathological processes is crucial in terms of efficient prevention, clinical signs’ identification, prognosis definition, and therapy optimization. In this regard, the omics-approach has become a powerful tool to identify sex/gender-specific disease markers, with potential benefits also in terms of socio-psychological wellbeing for each individual, and cost-effectiveness for National Healthcare systems. “Being a male or being a female” is indeed important from a health point of view and it is no longer possible to avoid “sex and gender lens” when approaching patients. Accordingly, personalized healthcare must be based on evidence from targeted research studies aimed at understanding how sex and gender influence health across the entire life span. The rapid development of genetic tools in the molecular medicine approaches and their impact in healthcare is an example of highly specialized applications that have moved from specialists to primary care providers (e.g., pharmacogenetic and pharmacogenomic applications in routine medical practice). Gender medicine needs to follow the same path and become an established medical approach. To face the genetic, molecular and pharmacological bases of the existing sex/gender gap by means of omics approaches will pave the way to the discovery and identification of novel drug-targets/therapeutic protocols, personalized laboratory tests and diagnostic procedures (sex/gender-omics). In this scenario, the aim of the present review is not to simply resume the state-of-the-art in the field, rather an opportunity to gain insights into gender medicine, spanning from molecular up to social and psychological stances. The description and critical discussion of some key selected multidisciplinary topics considered as paradigmatic of sex/gender differences and sex/gender inequalities will allow to draft and design strategies useful to fill the existing gap and move forward.

The importance of selection and reporting of the sex of experimental animals

Biased use of males and females in animal studies or omitting specific details of the sex of animals used in publications limits reproducibility, hampers the pace and likelihood of new discoveries and invites adverse events in ensuing clinical research. Hence unbiased use of males and females in animal studies and specific reporting of animal details are increasingly required by funding bodies and scientific journals worldwide. An analysis to determine how males and females are used in animal studies involving the Commonwealth Scientific and Industrial Research Organisation (CSIRO) was undertaken as part of a process to review and further support best practice. In the study 178 publications that contain animal studies and include CSIRO researchers published between January 2014 and December 2016 were analysed for the sex of animals used. The overall sex distribution was males only 26.4% (47/178), females only 15.7% (28/178), males and females 18.0% (32/178) and sex of animals unspecified 39.9% (71/178). Reasons for this distribution include species biology, farming practices and commercial relevance. Although including sex as an experimental variable provides the most information, using both sexes in an animal study requires careful consideration and planning. Furthermore, there are valid biological and experimental reasons why sex distribution in a study may not be balanced. Biological reasons include cases where the severity of disease in a given model differs between males and females, superior husbandry or production traits in one sex and hermaphroditic species that change sex with age. Examples where experiments can only be undertaken in one sex of animal include animal models of female breast cancer, female reproductive traits, male fertility studies and post-castration welfare outcomes. Where there is no biological or experimental reason for using a single sex of animal, future studies should obtain an estimate of sex effect either from the literature or with a pilot study, and experiments should be planned and reported accordingly.

Implementation of the NIH Sex-Inclusion Policy: Attitudes and Opinions of Study Section Members

OBJECTIVE

On January 25th, 2016, the National Institutes of Health (NIH) implemented a policy requiring investigators to consider sex as a biological variable (SABV) within their grant submissions. We surveyed NIH study section members in 2016 and 2017 to determine their attitudes toward the policy and their perceptions regarding its implementation.

MATERIALS AND METHODS

Members of standing study sections and special emphasis panels who met in May, June, or July of 2016 and 2017, and had a publicly accessible e-mail address, were invited to participate in the survey (n = 4376 and n = 4710, respectively). The survey assessed participant demographics, knowledge and awareness of the SABV policy, and opinions regarding its utility and implementation.

RESULTS

A combined total of 1161 study section members participated in the survey for a response rate of 10.2% in 2016 and 15.1% in 2017. Respondents thought it was important for NIH-funded research to consider SABV (63% vs. 68%, p = 0.141) and that it will improve rigor and reproducibility (54% vs. 58%, p = 0.208). In terms of implementation, respondents indicated that the percentage of grants, which have successfully addressed and incorporated the policy, has significantly increased over time (p < 0.0001 for all endpoints). However, open-ended comments revealed concern for federal research funding, the overuse of experimental animals, and uncertainty surrounding grant scoring, as it relates to the SABV policy.

CONCLUSIONS

In this study, we show improving attitudes toward the sex-inclusive policy at NIH and that a statistically significant number of grants are addressing sex as a biological variable appropriately in their submissions. These data suggest the policy is becoming more well accepted, and it is thus anticipated that the reproducibility of scientific reports will increase over time and new discoveries using sex as a biological variable are on the horizon.

In search of decoding the syntax of the bioelements in human hair - A critical overview

The principles and practice of assessing the human body nutritional status or its environmental exposure through hair bioelement analysis are presented; herein the term "bioelements" is used as a common denominator for the major elements, trace elements and ultra-trace elements that are found in the human body. The accumulation of bioelements in the hair followed the statistical Power Law and the resulting sigmoid curve can be zoned into five regions in the ascending order of abundance (Low, Marginal, Adequate, High, and Excessive). The Adequate linear region of the bioassay sigmoid curve may be further subdivided into Low adequate, Recommended, and Ample adequate sub regions in a 60:30:10 ratio. Phosphorus was the most invariant bioelement since its hair concentration varies minimally regardless of the geographical place of living, the twenty years' time interval between the analyses, sex, race and instrumentation, i.e., atomic absorption spectrometry (AAS) atomic emission spectrometry (AES), and inductively plasma mass spectrometry (ICP MS). The osteotrophic (bone seeking) bioelements: Ca, Mg, and Sr, were 2.5 times more abundant in the hair of women than men. Two principal electrolytes of the body (Na, K) of the multi-bioelement hair profile were markedly increased in the depressed subjects diagnosed according to the American Psychiatric Association MSD-IV classification criteria. This increase in the hair Na and K of the depressed subjects was also associated with the decrease of vasopressin in the peripheral blood. The factor analysis revealed strong association of depression with sex (women > men in a 2.5:1 ratio), and with the metals from the Nieboer-Richardson series which form strong covalent bonds with proteins. We propose that the biological roots of depression are related to the non-specific impairment of the intracellular osmotic balance and ionic gradient due to the Na⁺K⁺ATPase failure from whatever cause acting either separately or in combination. We also put forward the idea of how children's autism may be related to a disproportional growth rate of various organs and tissues if children are fed up to their maximal genetic growth capacity. Finally, we have suggested the hypothesis on how the syntax or integration of the internal metabolic wiring of the bioelements in the body may occur. We have suggested the hypothetical existence of two complex distinct five-bioelement "rotors", the P-rotor and the N-rotor, where the P-rotor integrates the mileau interior (Na, K) ions with the perception/excitability (Mg, Ca) ions. Thus, the complex five element interdependence is cross related to P which provides the energy from the phosphorus of the DNA nucleotide backbone. The hair multi-bioelement profile analysis allows us to envisage the more complex structural metabolic features that bioelements are playing in our bodies.

Sex Differences in the Methylome and Transcriptome of the Human Liver and Circulating HDL-Cholesterol Levels

Context

Epigenetics may contribute to sex-specific differences in human liver metabolism.

Objective

To study the impact of sex on DNA methylation and gene expression in human liver.

Design/Setting

Cross-sectional, Kuopio Obesity Surgery Study.

Participants/Intervention

We analyzed DNA methylation with the Infinium HumanMethylation450 BeadChip in liver of an obese population (34 males, 61 females). Females had a higher high-density lipoprotein (HDL)-cholesterol levels compared with males. Gene expression was measured with the HumanHT-12 Expression BeadChip in a subset of 42 participants.

Results

Females displayed higher average methylation in the X-chromosome, whereas males presented higher methylation in autosomes. We found 9455 CpG sites in the X-chromosome and 33,205 sites in autosomes with significant methylation differences in liver between sexes (q < 0.05). When comparing our findings with published studies, 95% of the sex-specific differences in liver methylation in the X-chromosome were also found in pancreatic islets and brain, and 26 autosomal sites showed sex-specific methylation differences in the liver as well as in other human tissues. Furthermore, this sex-specific methylation profile in liver was associated with hepatic gene expression changes between males and females. Notably, females showed higher HDL-cholesterol levels, which were associated with higher KDM6A expression and epigenetic differences in human liver. Accordingly, silencing of KDM6A in cultured liver cells reduced HDL-cholesterol levels and APOA1 expression, which is a major component of HDL particles.

Conclusions

Human liver has a sex-specific methylation profile in both the X-chromosome and autosomes, which associates with hepatic gene expression changes and HDL-cholesterol. We identified KDM6A as a novel target that regulates HDL-cholesterol levels.

Improving pregnancy outcomes in humans through studies in sheep

Experimental studies that are relevant to human pregnancy rely on the selection of appropriate animal models as an important element in experimental design. Consideration of the strengths and weaknesses of any animal model of human disease is fundamental to effective and meaningful translation of preclinical research. Studies in sheep have made significant contributions to our understanding of the normal and abnormal development of the fetus. As a model of human pregnancy, studies in sheep have enabled scientists and clinicians to answer questions about the etiology and treatment of poor maternal, placental, and fetal health and to provide an evidence base for translation of interventions to the clinic. The aim of this review is to highlight the advances in perinatal human medicine that have been achieved following translation of research using the pregnant sheep and fetus.

Sex bias: Is it pervasive in otolaryngology clinical research?

OBJECTIVES/HYPOTHESIS

Recent initiatives highlight substantial sex bias in biomedical research. The objective was to determine whether sex bias is present in otolaryngology and whether sex is appropriately analyzed as an independent variable in otolaryngology clinical research.

STUDY DESIGN

Literature review.

METHODS

We systematically reviewed all 2016 articles in three major otolaryngology journals: The Laryngoscope, JAMA Otolaryngology-Head and Neck Surgery, and Otolaryngology-Head and Neck Surgery. Extracted data included study origin, location, subspecialty, number/sex of subjects, ≥50% sex matching (SM_≥50 ), and sex-based statistical analysis.

RESULTS

Six hundred of 1,209 articles comprising original clinical research were reviewed including 8,997,345,495 subjects (males: 3,898,559,264 [43.3%]; females: 5,095,592,583 [56.6%]; and unknown: 3,193,648 [0.04%]). There were 533/600 (88.8%) studies that included both sexes, eight (1.3%) included females only, five (0.8%) included males only, and 56 (9.3%) did not document participant sex. Only 280 studies (46.7%) analyzed data by sex, and 330 studies (60.7%) had SM_{≥ 50} . Sex-based statistical analysis and SM_{≥ 50} were similar in domestic and international studies (48.7% vs. 42.8% and 60.9% vs. 62%, respectively). Database studies performed sex-based statistical analysis more frequently than single and multi-institutional studies (79.1% vs. 40.4% and 43.4%, P < .00001). Analysis by sex was more frequently performed in head and neck surgery (53.6%) and pediatric otolaryngology (51.3%), whereas SM_≥50 was highest in pediatric otolaryngology (86.8%) and otology (82.4%).

CONCLUSIONS

Sex bias exists in the clinical otolaryngology literature, with less than half the studies analyzing sex. Acknowledging the intertwinement of sex with disease pathophysiology and outcomes is important. Eliminating sex bias in research and clinical care should become a major focus for otolaryngologists.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:858-864, 2019.

Gender differences in psychosocial outcomes of psychotherapy trial in patients with depression and coronary artery disease

INTRODUCTION

The biological and psychosocial risk profile differs between women and men with coronary artery disease (CAD). Depressive symptoms and Vital Exhaustion (VE) predict an unfavourable course of CAD. The secondary analysis of the SPIRR-CAD trial offered the possibility to examine gender as exposure variable of the clinical and psychological situation at baseline and in a variety of psychosocial measures as outcomes.

METHODS

In this trial, 450 men (78.9%) and 120 women (21.1%) with CAD (age ≤ 75 y), with mild to moderate depression (scoring ≥8 on the HADS), were randomized to usual care with or without a stepwise psychotherapy intervention. Beside clinical measures exhaustion and other indicators of depressive symptoms were collected at baseline and 18-month follow up.

RESULTS

Men had more signs and symptoms of heart disease at baseline, whereas women had higher psychosocial burden (e.g. negative affect). Women were more likely to live alone, had lower educational levels and employment rates and higher levels of depression and exhaustion. The psychotherapy intervention differed as a function of gender: In women, VE decreased from 29.4 ± 8.1 to 22.1 ± 11.7 in the intervention group (IG) and from 29.2 ± 8.2 to 25.1 ± 11.3 in the control group (CG). In men VE decreased from 23.3 + -10.8 to 21.2 ± 9.7 in the IG and from 23.6 ± 10.7 to 19.3 ± 11.3 in the CG (time x intervention x gender; F = 4.97; p = .026).

DISCUSSION

Women had a higher psychosocial burden than men. VE compared to other rating instruments of depressive symptoms suggested a stronger response to the intervention in women. VE may help to understand gender differences in psychotherapeutic treatment studies of CAD.

ISRCTN

76240576; clinicaltrials.gov.

The Healthy Pregnancy Research Program: transforming pregnancy research through a ResearchKit app

Although maternal morbidity and mortality in the US is among the worst of developed countries, pregnant women have been under-represented in research studies, resulting in deficiencies in evidence-based guidance for treatment. There are over two billion smartphone users worldwide, enabling researchers to easily and cheaply conduct extremely large-scale research studies through smartphone apps, especially among pregnant women in whom app use is exceptionally high, predominantly as an information conduit. We developed the first pregnancy research app that is embedded within an existing, popular pregnancy app for self-management and education of expectant mothers. Through the large-scale and simplified collection of survey and sensor generated data via the app, we aim to improve our understanding of factors that promote a healthy pregnancy for both the mother and developing fetus. From the launch of this cohort study on 16 March 2017 through 17 December 2017, we have enrolled 2058 pregnant women from all 50 states. Our study population is diverse geographically and demographically, and fairly representative of US population averages. We have collected 14,045 individual surveys and 107,102 total daily measurements of sleep, activity, blood pressure, and heart rate during this time. On average, women stayed engaged in the study for 59 days and 45 percent who reached their due date filled out the final outcome survey. During the first 9 months, we demonstrated the potential for a smartphone-based research platform to capture an ever-expanding array of longitudinal, objective, and subjective participant-generated data from a continuously growing and diverse population of pregnant women.

Cancer immunotherapy efficacy and patients' sex: a systematic review and meta-analysis

BACKGROUND

Despite the acknowledged sex-related dimorphism in immune system response, little is known about the effect of patients' sex on the efficacy of immune checkpoint inhibitors as cancer treatments. We did a systematic review and meta-analysis to assess the heterogeneity of immune checkpoint inhibitor efficacy between men and women.

METHODS

We systematically searched PubMed, MEDLINE, Embase, and Scopus, from database inception to Nov 30, 2017, for randomised controlled trials of immune checkpoint inhibitors (inhibitors of PD-1, CTLA-4, or both) that had available hazard ratios (HRs) for death according to patients' sex. We also reviewed abstracts and presentations from all major conference proceedings. We excluded non-randomised trials and considered only papers published in English. The primary endpoint was to assess the difference in efficacy of immune checkpoint inhibitors between men and women, measured in terms of the difference in overall survival log(HR) reported in male and female study participants. We calculated the pooled overall survival HR and 95% CI in men and women using a random-effects model, and assessed the heterogeneity between the two estimates using an interaction test.

FINDINGS

Of 7133 studies identified in our search, there were 20 eligible randomised controlled trials of immune checkpoint inhibitors (ipilimumab, tremelimumab, nivolumab, or pembrolizumab) that reported overall survival according to patients' sex. Overall, 11 351 patients with advanced or metastatic cancers (7646 [67%] men and 3705 [33%] women) were included in the analysis; the most common types of cancer were melanoma (3632 [32%]) and non-small-cell lung cancer (3482 [31%]). The pooled overall survival HR was 0·72 (95% CI 0·65-0·79) in male patients treated with immune checkpoint inhibitors, compared with men treated in control groups. In women treated with immune checkpoint inhibitors, the pooled overall survival HR compared with control groups was 0·86 (95% CI 0·79-0·93). The difference in efficacy between men and women treated with immune checkpoint inhibitors was significant (p=0·0019).

INTERPRETATION

Immune checkpoint inhibitors can improve overall survival for patients with advanced cancers such as melanoma and non-small-cell lung cancer, but the magnitude of benefit is sex-dependent. Future research should guarantee greater inclusion of women in trials and focus on improving the effectiveness of immunotherapies in women, perhaps exploring different immunotherapeutic approaches in men and women.

FUNDING

None.

Systematic review: methodological flaws in racial/ethnic reporting for gastroesophageal reflux disease

Health care disparities affecting the care of multiple disease groups are of growing concern internationally. Research guidelines, governmental institutions, and scientific journals have attempted to minimize disparities through policies regarding the collection and reporting of racial/ethnic data. One area where shortcomings remain is in gastroesophageal reflux disease (GERD). This systematic review, which adheres to the PRISMA statement, focuses on characterizing existing methodological weaknesses in research focusing on studies regarding the assessment, prevalence, treatment, and outcomes of GERD patients. Search terms included GERD and typical symptoms of GERD in ethnic groups or minorities. We reviewed 62 articles. The majority of studies did not report the race/ethnicity of all participants, and among those who did, very few followed accepted guidelines. While there were diverse participants, there was also diversity in the manner in which groups were labeled, making comparisons difficult. There appeared to be a disparity with respect to countries reporting race/ethnicity, with certain countries more likely to report this variable. Samples overwhelmingly consisted of the study country's majority population. The majority of studies justified the use of race/ethnicity as a study variable and investigated conceptually related factors such as socioeconomic status and environment. Yet, many studies wrote as if race/ethnicity reflected biological differences. Despite recommendations, it appears that GERD researchers around the world struggle with the appropriate and standard way to include, collect, report, and discuss race/ethnicity. Recommendations on ways to address these issues are included with the goal of preventing and identifying health care disparities.

Detection of drug safety signals from clinical trials data: Role of SUSARs

One of the main goals of safety management in clinical trials is to detect suspected unexpected serious adverse reactions (SUSARs). The unexpectedness concerns the nature, frequency or severity of an adverse reaction. Drug safety signals could thus be retrieved, and a study was performed to investigate whether SUSARs allow signal detection in pharmacovigilance. Data from six academic safety units were collected from 2005 to 2016. Characteristics of SUSARs were analysed and signals were identified i) by evaluating the presence of other causes, ii) by assessing the summary of product characteristics (SPC), iii) by searching for specific safety information in Pubmed and health agencies, and iv) by investigating the narrative of each case. Pharmacological plausibility was evaluated by compatible mechanism of reaction and time-to-onset. During the study period, 211 SUSARs were collected. They mostly concerned general disorders (26.1%) and protein kinase inhibitors (24.6%). After eliminating SUSARs with other causes or those considered as expected, 50 SUSARs (23.7%), involving a total of 115 drug-reaction pairs, concerned potential safety signals. Among these pairs, 12 (10.4%) were considered as pharmacologically plausible. This study indicates that one quarter of SUSARs collected in academic clinical trials refers to potential safety signals, especially for oncologic drugs. One tenth of drug-reaction pairs was considered to have a pharmacological plausibility and could merit further evaluation. This is the first study suggesting that SUSARs could be a source of safety signals and that their routine analysis should be complementary to spontaneous reporting.

Sex-specific differences in hypertension and associated cardiovascular disease

Although intrinsic mechanisms that regulate arterial blood pressure (BP) are similar in men and women, marked variations exist at the molecular, cellular and tissue levels. These physiological disparities between the sexes likely contribute to differences in disease onset, susceptibility, prevalence and treatment responses. Key systems that are important in the development of hypertension and cardiovascular disease (CVD), including the sympathetic nervous system, the renin-angiotensin-aldosterone system and the immune system, are differentially activated in males and females. Biological age also contributes to sexual dimorphism, as premenopausal women experience a higher degree of cardioprotection than men of similar age. Furthermore, sex hormones such as oestrogen and testosterone as well as sex chromosome complement likely contribute to sex differences in BP and CVD. At the cellular level, differences in cell senescence pathways may contribute to increased longevity in women and may also limit organ damage caused by hypertension. In addition, many lifestyle and environmental factors - such as smoking, alcohol consumption and diet - may influence BP and CVD in a sex-specific manner. Evidence suggests that cardioprotection in women is lost under conditions of obesity and type 2 diabetes mellitus. Treatment strategies for hypertension and CVD that are tailored according to sex could lead to improved outcomes for affected patients.

Dyslipidemia and Associated Cardiovascular Risk Factors among Young Nepalese University Students

Introduction

Cardiovascular diseases are one of the main causes of morbidity and mortality worldwide, atherosclerosis being the principal underlying cause of cardiovascular diseases. Early detection of dyslipidemia and long-term prevention of atherosclerosis by controlling risk factors should begin in young age. The purpose of this study was to assess dyslipidemia and associated cardiovascular risk factors among university students of Nepal.

Methods

A sample of 280 students aged 17–24 years, were selected randomly from Institute of Medicine, Tribhuvan University. An interview-based questionnaire was designed and information was collected on the basis of age, gender, smoking and alcohol consumption. Body mass index and waist-to-hip ratio of all participants were calculated. Fasting blood samples were collected from all participants and assayed for fasting serum total cholesterol, triglyceride, high-density lipoprotein and low-density lipoprotein.

Results

Overall, dyslipidemia was seen as hypercholesterolemia in 31 (11.1%), elevated low-density lipoprotein in 34 (12.1%), low high-density lipoprotein in 95 (33.9%) and hypertriglyceridemia in 39 (13.9%). Current smoking and binge drinking were significantly associated with hypercholesterolemia. Gender, binge drinking, and current smoking were found to be significantly associated with elevated low-density lipoprotein. All factors were significantly associated with hypertriglyceridemia. There was no statistically significant association between risk factors and the low high-density lipoprotein. Body mass index and waist-to-hip ratio were significantly higher in subjects with hypercholesterolemia, hypertriglyceridemia, and elevated low-density lipoprotein level.

Conclusions

The prevalence of dyslipidemia was high in young Nepalese university students. Screening the levels of lipids in youth, especially those at risk, and accurate follow-up of those with dyslipidemia can be done to reduce morbidity and mortality.

Potential Sex Bias Exists in Orthopaedic Basic Science and Translational Research

BACKGROUND

Potential sex bias has been shown in general surgery basic science and translational research, with unequal representation of male and female specimens. Because basic science research forms the foundation for clinical studies on which patient care is based, it is important that this research equally consider both sexes. The purpose of this study was to determine if potential sex bias exists in the basic science and translational orthopaedic literature.

METHODS

A systematic review was conducted of all articles published in 2014 in The Journal of Bone & Joint Surgery, Clinical Orthopaedics and Related Research, The Bone & Joint Journal, and the Journal of Orthopaedic Research (JOR). All original research articles utilizing animals, cells, or cadavers were included. The data abstracted included study type, sex of specimen studied, and presence of sex-based reporting of data. A second review was performed of all basic science articles published in JOR in 1994, 2004, and 2014 to compare sex bias trends across 3 decades. Distributions of variables were compared using the Fisher exact test, with significance defined as p < 0.05.

RESULTS

Of 1,693 articles reviewed, 250 (15%) were included: 122 animal-based studies (49%), 71 cell-based studies (28%), and 57 human cadaver-based studies (23%). Overall, authors in 88 studies (35%) did not report the sex of animals, cells, or cadavers used. Of 162 studies in which the authors did report sex, 69 (43%) utilized male only, 40 (25%) utilized female only, and 53 (33%) utilized both sexes. Of those studies that used both sexes, authors in only 7 studies (13%) reported sex-based results. A subanalysis of JOR articles across 3 decades revealed a significant increase in studies specifying sex (p = 0.01) from 2004 to 2014.

CONCLUSIONS

Potential sex bias exists in orthopaedic surgery basic science and translational research, with an overrepresentation of male specimens.

CLINICAL RELEVANCE

Inequality in sex representation must be addressed as basic science and translational research creates the foundation for subsequent clinical research, which ultimately informs clinical care.

The Toll pathway underlies host sexual dimorphism in resistance to both Gram-negative and Gram-positive bacteria in mated Drosophila

BACKGROUND

Host sexual dimorphism is being increasingly recognized to generate strong differences in the outcome of infectious disease, but the mechanisms underlying immunological differences between males and females remain poorly characterized. Here, we used Drosophila melanogaster to assess and dissect sexual dimorphism in the innate response to systemic bacterial infection.

RESULTS

We demonstrated sexual dimorphism in susceptibility to infection by a broad spectrum of Gram-positive and Gram-negative bacteria. We found that both virgin and mated females are more susceptible than mated males to most, but not all, infections. We investigated in more detail the lower resistance of females to infection with Providencia rettgeri, a Gram-negative bacterium that naturally infects D. melanogaster. We found that females have a higher number of phagocytes than males and that ablation of hemocytes does not eliminate the dimorphism in resistance to P. rettgeri, so the observed dimorphism does not stem from differences in the cellular response. The Imd pathway is critical for the production of antimicrobial peptides in response to Gram-negative bacteria, but mutants for Imd signaling continued to exhibit dimorphism even though both sexes showed strongly reduced resistance. Instead, we found that the Toll pathway is responsible for the dimorphism in resistance. The Toll pathway is dimorphic in genome-wide constitutive gene expression and in induced response to infection. Toll signaling is dimorphic in both constitutive signaling and in induced activation in response to P. rettgeri infection. The dimorphism in pathway activation can be specifically attributed to Persephone-mediated immune stimulation, by which the Toll pathway is triggered in response to pathogen-derived virulence factors. We additionally found that, in absence of Toll signaling, males become more susceptible than females to the Gram-positive Enterococcus faecalis. This reversal in susceptibility between male and female Toll pathway mutants compared to wildtype hosts highlights the key role of the Toll pathway in D. melanogaster sexual dimorphism in resistance to infection.

CONCLUSION

Altogether, our data demonstrate that Toll pathway activity differs between male and female D. melanogaster in response to bacterial infection, thus identifying innate immune signaling as a determinant of sexual immune dimorphism.

Low-Density Lipoprotein Receptor Deficiency Attenuates Neuroinflammation through the Induction of Apolipoprotein E

Objective

We aimed to determine the role of the low-density lipoprotein receptor (LDLr) in neuroinflammation by inducing experimental autoimmune encephalomyelitis (EAE) in ldlr knock out mice.

Methods

MOG_35-55 induced EAE in male and female ldlr^-/- mice was assessed clinically and histopathologically. Expression of inflammatory mediators and apolipoprotein E (apoE) was investigated by qPCR. Changes in protein levels of apoE and tumor necrosis factor alpha (TNFα) were validated by western blot and ELISA, respectively.

Results

Ldlr^-/--attenuated EAE disease severity in female, but not in male, EAE mice marked by a reduced proinflammatory cytokine production in the central nervous system of female ldlr^-/- mice. Macrophages from female ldlr^-/- mice showed a similar decrease in proinflammatory mediators, an impaired capacity to phagocytose myelin and enhanced secretion of the anti-inflammatory apoE. Interestingly, apoE/ldlr double knock out abrogated the beneficial effect of ldlr depletion in EAE.

Conclusion

Collectively, we show that ldlr^-/- reduces EAE disease severity in female but not in male EAE mice, and that this can be explained by increased levels of apoE in female ldlr^-/- mice. Although the reason for the observed sexual dimorphism remains unclear, our findings show that LDLr and associated apoE levels are involved in neuroinflammatory processes.

Sex and gender matters : A sex-specific analysis of original articles published in the Wiener klinische Wochenschrift between 2013 and 2015

BACKGROUND

The variables sex and gender are significantly related to health and disease of women and men. Aiming at quality research, biomedical publications need to account for the key variables sex and gender.

METHODS

All original articles published in the Wiener klinische Wochenschrift between 2013 and 2015 were extracted into a database. As a result, the 195 published articles were selected for review led by the Sex and Gender Equity in Research Guidelines (SAGER) by the European Association of Science Editors (EASE). The slightest indications of mentioning sex and/or gender were assessed by two reviewers independently from one another.

RESULTS

Of the 195 publications 4 specified sex and/or gender in the title, and 62 in the abstract. None of the authors reported whether the variables sex and/or gender may have relevance and were taken into account in the design of the study. Of the 195 publications 48 mentioned the potential implications of sex and/or gender on the study results.

CONCLUSION

In the time span studied most of the selected articles of this journal did not account for the variables sex and/or gender systematically or adequately. For future research the existing guidelines can help authors and editors to overcome gender bias due to inadequate methods. Applying sex and gender-sensitive methods to biomedical and health research is necessary for high quality and as a precondition for results which are generalizable and applicable to both women and men.

Uncertainty on the effectiveness and safety of rivaroxaban in premenopausal women with atrial fibrillation: empirical evidence needed

Background

Novel anticoagulations (NOACs) are increasingly prescribed for the prevention of stroke in premenopausal women with atrial fibrillation. Small studies suggest NOACs are associated with a higher risk of abnormal uterine bleeds than vitamin K antagonists (VKAs). Because there is no direct empirical evidence on the benefit/risk profile of rivaroxaban compared to VKAs in this subgroup, we synthesize available indirect evidence, estimate decision uncertainty on the treatments, and assess whether further research in premenopausal women is warranted.

Methods

A Markov model with annual cycles and a lifetime horizon was developed comparing rivaroxaban (the most frequently prescribed NOAC in this population) and VKAs. Clinical event rates, associated quality adjusted life years, and health care costs were obtained from different sources and adjusted for gender, age, and history of stroke. A Monte Carlo simulation with 10,000 iterations was then performed for a hypothetical cohort of premenopausal women, estimated to be reflective of the population of premenopausal women with AF in The Netherlands.

Results

In the simulation, rivaroxaban is the better treatment option for the prevention of ischemic strokes in premenopausal women in 61% of the iterations. Similarly, this is 98% for intracranial hemorrhages, 24% for major abnormal uterine bleeds, 1% for minor abnormal uterine bleeds, 9% for other major extracranial hemorrhages, and 23% for other minor extracranial hemorrhages. There is a 78% chance that rivaroxaban offers the most quality-adjusted life years. The expected value of perfect information in The Netherlands equals 122 quality-adjusted life years and 22 million Euros.

Conclusions

There is a 22% risk that rivaroxaban offers a worse rather than a better benefit/risk profile than vitamin K antagonists in premenopausal women. Although rivaroxaban is preferred over VKAs in this population, further research is warranted, and should preferably take the shape of an internationally coordinated registry study including other NOACs.

Electronic supplementary material

The online version of this article (10.1186/s12872-017-0692-1) contains supplementary material, which is available to authorized users.

Quantifiable effects of regular exercise on zinc status in a healthy population-A systematic review

Zinc is an essential mineral of which its functions have potential implications on exercise performance and beneficial adaptations of physical activity. While the effects of aerobic exercise on zinc metabolism acutely have been well described, the effect of long-term exercise training on zinc status remains unclear. The present review aims to determine the effects of exercise training on markers of zinc status in an apparently healthy adult population. We conducted a systematic literature search on PubMed, Scopus, SPORTDiscus and Cochrane Library from inception to 28 January 2016 to identify interventional or cohort studies that investigated the effects of exercise training on indices of zinc status. Pairwise comparisons of mean differences in within-group change were calculated and summarised visually in forest plots. Six studies satisfied the inclusion criteria for the systematic review, of which 5 studies included data on changes in serum zinc concentrations and 3 studies provided changes in dietary zinc intake. Two comparisons showed significantly higher increase of serum zinc concentrations in the exercise group compared to control, while one comparison reported significantly lower change in serum zinc for the exercising group. The exercise groups consumed significantly higher dietary zinc compared to controls in two comparisons. The present review revealed an incomplete evidence base in evaluating the effect of long-term exercise training on markers of zinc status. Further well-designed investigations are required to elucidate the relationship for establishment of dietary recommendation in populations who are continuing exercise interventions.

Reporting of sex and gender in randomized controlled trials in Canada: a cross-sectional methods study

BACKGROUND

Accurate reporting on sex and gender in health research is integral to ensuring that health interventions are safe and effective. In Canada and internationally, governments, research organizations, journal editors, and health agencies have called for more inclusive research, provision of sex-disaggregated data, and the integration of sex and gender analysis throughout the research process. Sex and gender analysis is generally defined as an approach for considering how and why different subpopulations (e.g., of diverse genders, ages, and social locations) may experience health conditions and interventions in different or similar ways.The objective of this study was to assess the extent and nature of reporting about sex and/or gender, including whether sex and gender analysis (SGA) was carried out in a sample of Canadian randomized controlled trials (RCTs) with human participants.

METHODS

We searched MEDLINE from 01 January 2013 to 23 July 2014 using a validated filter for identification of RCTs, combined with terms related to Canada. Two reviewers screened the search results to identify the first 100 RCTs that were either identified in the trial publication as funded by a Canadian organization or which had a first or last author based in Canada. Data were independently extracted by two people from 10% of the RCTs during an initial training period; once agreement was reached on this sample, the remainder of the data extraction was completed by one person and verified by a second.

RESULTS

The search yielded 1433 records. We screened 256 records to identify 100 RCTs which met our eligibility criteria. The median sample size of the RCTs was 107 participants (range 12-6085). While 98% of studies described the demographic composition of their participants by sex, only 6% conducted a subgroup analysis across sex and 4% reported sex-disaggregated data. No article defined "sex" and/or "gender." No publication carried out a comprehensive sex and gender analysis.

CONCLUSIONS

Findings highlight poor uptake of sex and gender considerations in the Canadian RCT context and underscore the need for better articulated guidance on sex and gender analysis to improve reporting of evidence, inform policy development, and guide future research.

Sex disparities in ideal cardiovascular health

OBJECTIVE

To quantify the gap in the distribution of ideal cardiovascular health (CVH) between men and women accounting for comorbidities, socioeconomic and psychological confounding factors.

METHODS

A cross-sectional analysis was conducted among 9012 French men and women aged 50-75 years who were participants of the Paris Prospective Study 3. Each of the seven metrics was defined according to the American Heart Association criteria, and the CVH was considered as poor (0 or 1 ideal health metric), intermediate (2, 3 or 4 ideal health metrics) and ideal (5-7 ideal health metrics). The odds of intermediate and ideal CVH in women compared with men were estimated by multivariate polytomous logistic regression analysis using poor CVH as the reference category.

RESULTS

The mean age was 59.49 year (SD 6.25) and there were 38.54% of women. Though women were slightly older, less educated, more deprived, more often depressed, they were twice more often in ideal CVH than men (14.77% vs 6.84%, p<0.0001). After adjustment for age, deprivation score, education and depression, women were four times more often in ideal CVH (OR 4.01, 95% CI 3.42 to 4.69) and two times more often in intermediate CVH (OR 2.07, 95% CI 1.88 to 2.28) than men.

CONCLUSION

The sex disparities in the prevalence of ideal CVH have the potential to guide sex-specific strategies for improving CVH status in the general population.

CLINICAL TRIAL REGISTRATION

NCT00741728;Pre-results.

Androgen-mediated sex bias impairs efficiency of leukotriene biosynthesis inhibitors in males

Proinflammatory leukotrienes (LTs) are produced by 5-lipoxygenase (5-LO) aided by 5-LO-activating protein (FLAP). LT biosynthesis inhibitors are currently under clinical investigation as treatments for respiratory and cardiovascular diseases. Here, we have revealed a sex bias in the efficiency of clinically relevant LT biosynthesis inhibitors, showing that their effects are superior in females. We found that androgens cause these sex differences by impeding the LT-biosynthetic 5-LO/FLAP complex assembly. Lower doses of the FLAP inhibitor MK886 were required to reduce LTB4 levels in exudates of female versus male mice and rats. Following platelet-activating factor-induced shock, MK886 increased survival exclusively in female mice, and this effect was abolished by testosterone administration. FLAP inhibitors and the novel-type 5-LO inhibitors licofelone and sulindac sulfide exhibited higher potencies in human blood from females, and bioactive 5-LO/FLAP complexes were formed in female, but not male, human and murine leukocytes. Supplementation of female blood or leukocytes with 5α-dihydrotestosterone abolished the observed sex differences. Our data suggest that females may benefit from anti-LT therapy to a greater extent than males, prompting consideration of sex issues in LT modifier development.

The Precision Medicine Nation

The United States' ambitious Precision Medicine Initiative proposes to accelerate exponentially the adoption of precision medicine, an approach to health care that tailors disease diagnosis, treatment, and prevention to individual variability in genes, environment, and lifestyle. It aims to achieve this by creating a cohort of volunteers for precision medicine research, accelerating biomedical research innovation, and adopting policies geared toward patients' empowerment. As strategies to implement the PMI are formulated, critical consideration of the initiative's ethical and sociopolitical dimensions is needed. Drawing on scholarship of nationalism and democracy, we discuss the PMI's construction of what we term "genomic citizenship"; the possible normative obligations arising therefrom; and the ethical, legal, and social challenges that will ensue. Although the PMI is a work in progress, discussion of the existing and emerging issues can facilitate the development of policies, structures, and procedures that can maximize the initiative's ability to produce equitable and socially sensitive outcomes. Our analysis can also be applied to other population-based, precision medicine research programs.

Determining If Sex Bias Exists in Human Surgical Clinical Research

Importance

Sex is a variable that is poorly controlled for in clinical research.

Objectives

To determine if sex bias exists in human surgical clinical research, to determine if data are reported and analyzed using sex as an independent variable, and to identify specialties in which the greatest and least sex biases exist.

Design, Setting, and Participants

For this bibliometric analysis, data were abstracted from 1303 original peer-reviewed articles published from January 1, 2011, through December 31, 2012, in 5 surgery journals.

Main Outcomes and Measures

Study type, location, number and sex of participants, degree of sex matching of included participants, and inclusion of sex-based reporting, statistical analysis, and discussion of data.

Results

Of 2347 articles reviewed, 1668 (71.1%) included human participants. After excluding 365 articles, 1303 remained: 17 (1.3%) included males only, 41 (3.1%) included females only, 1020 (78.3%) included males and females, and 225 (17.3%) did not document the sex of the participants. Although female participants represent more than 50% (n = 57 688 606) of the total number (115 377 213) included, considerable variability existed with the number of male (46 111 818), female (58 805 665), and unspecified (10 459 730) participants included among the journals, between US domestic and international studies, and between single vs multicenter studies. For articles included in the study, 38.1% (497 of 1303) reported these data by sex, 33.2% (432 of 1303) analyzed these data by sex, and 22.9% (299 of 1303) included a discussion of sex-based results. Sex matching of the included participants in the research overall was poor, with 45.2% (589 of 1303) of the studies matching the inclusion of both sexes by 50%. During analysis of the different surgical specialties, a wide variation in sex-based inclusion, matching, and data reporting existed, with colorectal surgery having the best matching of male and female participants and cardiac surgery having the worst.

Conclusions and Relevance

Sex bias exists in human surgical clinical research. Few studies included men and women equally, less than one-third performed data analysis by sex, and there was wide variation in inclusion and matching of the sexes among the specialties and the journals reviewed. Because clinical research is the foundation for evidence-based medicine, it is imperative that this disparity be addressed so that therapies benefit both sexes.

Sex-biased eicosanoid biology: Impact for sex differences in inflammation and consequences for pharmacotherapy

The incidence, severity and progression of autoimmune diseases (e.g. scleroderma, multiple sclerosis, rheumatoid arthritis) and certain inflammatory diseases (e.g. asthma) are sex-biased where these pathologies dominate in women. However, other immune disorders such as sepsis, post-surgery infections and gout display higher incidence and severity in men. The molecular and cellular basis underlying this sex dimorphism remains incompletely elucidated but may provide important insights for sex-specific pharmacotherapy. Nevertheless, the sex as a variable in biochemical and preclinical research on inflammation is often neglected. Thus, respective animal studies are routinely performed with males, and experiments with isolated cells rarely report the sex of the donor. However, sex differences on the cellular level do exist, in particular related to inflammatory processes that prompt for sex-specific appreciation of inflammation research. For instance, the biosynthesis of pro-inflammatory eicosanoids is sex-biased where leukotriene (LT) formation is under control of testosterone that regulates the subcellular localization of the key enzyme 5-lipoxygenase, with possible implications for gender-tailored pharmacotherapy of LT-related disorders (i.e. asthma). Moreover, prostaglandin (PG) production is sex-biased, and sex-dependent efficacy of aspirin was evident in several clinical trials. Here, we highlight the sex bias in eicosanoid biology possibly underlying the obvious sex disparities in inflammation, stimulating scientists to take sex into account when studying the pathophysiology and pharmacotherapy of inflammatory diseases.

Sex and gender differences in chronic kidney disease: progression to end-stage renal disease and haemodialysis

Sex and gender differences are of fundamental importance in most diseases, including chronic kidney disease (CKD). Men and women with CKD differ with regard to the underlying pathophysiology of the disease and its complications, present different symptoms and signs, respond differently to therapy and tolerate/cope with the disease differently. Yet an approach using gender in the prevention and treatment of CKD, implementation of clinical practice guidelines and in research has been largely neglected. The present review highlights some sex- and gender-specific evidence in the field of CKD, starting with a critical appraisal of the lack of inclusion of women in randomized clinical trials in nephrology, and thereafter revisits sex/gender differences in kidney pathophysiology, kidney disease progression, outcomes and management of haemodialysis care. In each case we critically consider whether apparent discrepancies are likely to be explained by biological or psycho-socioeconomic factors. In some cases (a few), these findings have resulted in the discovery of disease pathways and/or therapeutic opportunities for improvement. In most cases, they have been reported as merely anecdotal findings. The aim of the present review is to expose some of the stimulating hypotheses arising from these observations as a preamble for stricter approaches using gender for the prevention and treatment of CKD and its complications.

Exploring acute-to-chronic neuropathic pain in rats after contusion spinal cord injury

Spinal cord injury (SCI) causes chronic pain in 65% of individuals. Unfortunately, current pain management is inadequate for many SCI patients. Rodent models could help identify how SCI pain develops, explore new treatment strategies, and reveal whether acute post-SCI morphine worsens chronic pain. However, few studies explore or compare SCI-elicited neuropathic pain in rats. Here, we sought to determine how different clinically relevant contusion SCIs in male and female rats affect neuropathic pain, and whether acute morphine worsens later chronic SCI pain. First, female rats received sham surgery, or 150kDyn or 200kDyn midline T9 contusion SCI. These rats displayed modest mechanical allodynia and long-lasting thermal hyperalgesia. Next, a 150kDyn (1s dwell) midline contusion SCI was performed in male and female rats. Interestingly, males, but not females showed SCI-elicited mechanical allodynia; rats of both sexes had thermal hyperalgesia. In this model, acute morphine treatment had no significant effect on chronic neuropathic pain symptoms. Unilateral SCIs can also elicit neuropathic pain that could be exacerbated by morphine, so male rats received unilateral T13 contusion SCI (100kDyn). These rats exhibited significant, transient mechanical allodynia, but not thermal hyperalgesia. Acute morphine did not exacerbate chronic pain. Our data show that specific rat contusion SCI models cause neuropathic pain. Further, chronic neuropathic pain elicited by these contusion SCIs was not amplified by our course of early post-trauma morphine. Using clinically relevant rat models of SCI could help identify novel pain management strategies.

A gene network regulated by the transcription factor VGLL3 as a promoter of sex-biased autoimmune diseases

Autoimmune diseases affect 7.5% of the US population, and they are among the leading causes of death and disability. A notable feature of many autoimmune diseases is their greater prevalence in females than in males, but the underlying mechanisms of this have remained unclear. Through the use of high-resolution global transcriptome analyses, we demonstrated a female-biased molecular signature associated with susceptibility to autoimmune disease and linked this to extensive sex-dependent co-expression networks. This signature was independent of biological age and sex-hormone regulation and was regulated by the transcription factor VGLL3, which also had a strong female-biased expression. On a genome-wide level, VGLL3-regulated genes had a strong association with multiple autoimmune diseases, including lupus, scleroderma and Sjögren's syndrome, and had a prominent transcriptomic overlap with inflammatory processes in cutaneous lupus. These results identified a VGLL3-regulated network as a previously unknown inflammatory pathway that promotes female-biased autoimmunity. They demonstrate the importance of studying immunological processes in females and males separately and suggest new avenues for therapeutic development.

The role of sex steroids in white adipose tissue adipocyte function

With the increasing knowledge that gender influences normal physiology, much biomedical research has begun to focus on the differential effects of sex on tissue function. Sexual dimorphism in mammals is due to the combined effects of both genetic and hormonal factors. Hormonal factors are mutable particularly in females in whom the estrous cycle dominates the hormonal milieu. Given the severity of the obesity epidemic and the fact that there are differences in the obesity rates in men and women, the role of sex in white adipose tissue function is being recognized as increasingly important. Although sex differences in white adipose tissue distribution are well established, the mechanisms affecting differential function of adipocytes within white adipose tissue in males and females remain largely understudied and poorly understood. One of the largest differences in the endocrine environment in males and females is the concentration of circulating androgens and estrogens. This review examines the effects of androgens and estrogens on lipolysis/lipogenesis, adipocyte differentiation, insulin sensitivity and adipokine production in adipocytes from white adipose tissue with a specific emphasis on the sexual dimorphism of adipocyte function in white adipose tissue during both health and disease.

The evolution of sex-specific virulence in infectious diseases

Fatality rates of infectious diseases are often higher in men than women. Although this difference is often attributed to a stronger immune response in women, we show that differences in the transmission routes that the sexes provide can result in evolution favouring pathogens with sex-specific virulence. Because women can transmit pathogens during pregnancy, birth or breast-feeding, pathogens adapt, evolving lower virulence in women. This can resolve the long-standing puzzle on progression from Human T-cell Lymphotropic Virus Type 1 (HTLV-1) infection to lethal Adult T-cell Leukaemia (ATL); a progression that is more likely in Japanese men than women, while it is equally likely in Caribbean women and men. We argue that breastfeeding, being more prolonged in Japan than in the Caribbean, may have driven the difference in virulence between the two populations. Our finding signifies the importance of investigating the differences in genetic expression profile of pathogens in males and females.

Many infectious diseases are more likely to progress to serious illness or death in men than in women, which has been attributed to a stronger immune response in women. Here, the authors propose that pathogen transmission from mother to child favours the evolution of lower virulence in women, and argue that the higher risk of HTLV-1 infection progressing to leukaemia in Japanese men is due to prolonged breastfeeding in Japan.

Improving the Identification of Phenotypic Abnormalities and Sexual Dimorphism in Mice When Studying Rare Event Categorical Characteristics

Biological research frequently involves the study of phenotyping data. Many of these studies focus on rare event categorical data, and functional genomics studies typically study the presence or absence of an abnormal phenotype. With the growing interest in the role of sex, there is a need to assess the phenotype for sexual dimorphism. The identification of abnormal phenotypes for downstream research is challenged by the small sample size, the rare event nature, and the multiple testing problem, as many variables are monitored simultaneously. Here, we develop a statistical pipeline to assess statistical and biological significance while managing the multiple testing problem. We propose a two-step pipeline to initially assess for a treatment effect, in our case example genotype, and then test for an interaction with sex. We compare multiple statistical methods and use simulations to investigate the control of the type-one error rate and power. To maximize the power while addressing the multiple testing issue, we implement filters to remove data sets where the hypotheses to be tested cannot achieve significance. A motivating case study utilizing a large scale high-throughput mouse phenotyping data set from the Wellcome Trust Sanger Institute Mouse Genetics Project, where the treatment is a gene ablation, demonstrates the benefits of the new pipeline on the downstream biological calls.

Detergents: Friends not foes for high-performance membrane proteomics toward precision medicine

Precision medicine, particularly therapeutics, emphasizes the atomic-precise, dynamic, and systems visualization of human membrane proteins and their endogenous modifiers. For years, bottom-up proteomics has grappled with removing and avoiding detergents, yet faltered at the therapeutic-pivotal membrane proteins, which have been tackled by classical approaches and are known for decades refractory to single-phase aqueous or organic denaturants. Hydrophobicity and aggregation commonly challenge tissue and cell lysates, biofluids, and enriched samples. Frequently, expected membrane proteins and peptides are not identified by shotgun bottom-up proteomics, let alone robust quantitation. This review argues the cause of this proteomic crisis is not detergents per se, but the choice of detergents. Recently, inclusion of compatible detergents for membrane protein extraction and digestion has revealed stark improvements in both quantitative and structural proteomics. This review analyzes detergent properties behind recent proteomic advances, and proposes that rational use of detergents may reconcile outstanding membrane proteomics dilemmas, enabling ultradeep coverage and minimal artifacts for robust protein and endogenous PTM measurements. The simplicity of detergent tools confers bottom-up membrane proteomics the sophistication toward precision medicine.

Metabolic Profiling of Total Physical Activity and Sedentary Behavior in Community-Dwelling Men

Objective

Physical activity is known to be preventive against various non-communicable diseases. We investigated the relationship between daily physical activity level and plasma metabolites using a targeted metabolomics approach in a population-based study.

Methods

A total of 1,193 participants (male, aged 35 to 74 years) with fasting blood samples were selected from the baseline survey of a cohort study. Information on daily total physical activity, classified into four levels by quartile of metabolic equivalent scores, and sedentary behavior, defined as hours of sitting per day, was collected through a self-administered questionnaire. Plasma metabolite concentrations were quantified by capillary electrophoresis mass spectrometry method. We performed linear regression analysis models with multivariable adjustment and corrected p-values for multiple testing in the original population (n = 808). The robustness of the results was confirmed by replication analysis in a separate population (n = 385) created by random allocation.

Results

Higher levels of total physical activity were associated with various metabolite concentrations, including lower concentrations of amino acids and their derivatives, and higher concentrations of pipecolate (FDR p <0.05 in original population). The findings persisted after adjustment for age, body mass index, smoking, alcohol intake, and energy intake. Isoleucine, leucine, valine, 4-methyl-2-oxoisopentanoate, 2-oxoisopentanoate, alanine, and proline concentrations were lower with a shorter sitting time.

Conclusions

Physical activity is related to various plasma metabolites, including known biomarkers for future insulin resistance or type 2 diabetes. These metabolites might potentially play a key role in the protective effects of higher physical activity and/or less sedentary behavior on non-communicable diseases.

Sex differences in response to miRNA-34a therapy in mouse models of cardiac disease: identification of sex-, disease- and treatment-regulated miRNAs

KEY POINTS

MicroRNA (miRNA)-based therapies are in development for numerous diseases, including heart disease. Currently, very limited basic information is available on the regulation of specific miRNAs in male and female hearts in settings of disease. The identification of sex-specific miRNA signatures has implications for translation into the clinic and suggests the need for customised therapy. In the present study, we found that a miRNA-based treatment inhibiting miRNA-34a (miR-34a) was more effective in females in a setting of moderate dilated cardiomyopathy than in males. Furthermore, the treatment showed little benefit for either sex in a setting of more severe dilated cardiomyopathy associated with atrial fibrillation. The results highlight the importance of understanding the effect of miRNA-based therapies in cardiac disease settings in males and females.

ABSTRACT

MicroRNA (miRNA)-34a (miR-34a) is elevated in the diseased heart in mice and humans. Previous studies have shown that inhibiting miR-34a in male mice in settings of pathological cardiac hypertrophy or ischaemia protects the heart against progression to heart failure. Whether inhibition of miR-34a protects the female heart is unknown. Furthermore, the therapeutic potential of silencing miR-34a in settings of dilated cardiomyopathy (DCM) and atrial fibrillation (AF) has not been assessed previously. In the present study, we examined the effect of silencing miR-34a in males and females in (1) a model of moderate DCM and (2) a model of severe DCM with AF. The cardiac disease models were administered with a locked nucleic acid-modified oligonucleotide (LNA-antimiR-34a) at 6-7 weeks of age when the models display cardiac dysfunction and conduction abnormalities. Cardiac function and morphology were measured 6 weeks after treatment. In the present study, we show that inhibition of miR-34a provides more protection in the DCM model in females than males. Disease prevention in LNA-antimiR-34a treated DCM female mice was characterized by attenuated heart enlargement and lung congestion, lower expression of cardiac stress genes (B-type natriuretic peptide, collagen gene expression), less cardiac fibrosis and better cardiac function. There was no evidence of significant protection in the severe DCM and AF model in either sex. Sex- and treatment-dependent regulation of miRNAs was also identified in the diseased heart, and may explain the differential response of males and females. These studies highlight the importance of examining the impact of miRNA-based drugs in both sexes and under different disease conditions.

Systematic Analysis of Adverse Event Reports for Sex Differences in Adverse Drug Events

Increasing evidence has shown that sex differences exist in Adverse Drug Events (ADEs). Identifying those sex differences in ADEs could reduce the experience of ADEs for patients and could be conducive to the development of personalized medicine. In this study, we analyzed a normalized US Food and Drug Administration Adverse Event Reporting System (FAERS). Chi-squared test was conducted to discover which treatment regimens or drugs had sex differences in adverse events. Moreover, reporting odds ratio (ROR) and P value were calculated to quantify the signals of sex differences for specific drug-event combinations. Logistic regression was applied to remove the confounding effect from the baseline sex difference of the events. We detected among 668 drugs of the most frequent 20 treatment regimens in the United States, 307 drugs have sex differences in ADEs. In addition, we identified 736 unique drug-event combinations with significant sex differences. After removing the confounding effect from the baseline sex difference of the events, there are 266 combinations remained. Drug labels or previous studies verified some of them while others warrant further investigation.

Barriers to a cure for HIV in women

Introduction

Distinct biological factors exist that affect the natural history of HIV and the host immune response between women and men. These differences must be addressed to permit the optimal design of effective HIV eradication strategies for much of the HIV-positive population.

Methods and results

Here, we review the literature on sex-based differences in HIV pathogenesis and natural history in tissues and anatomic compartments, HIV latency and transcriptional activity, and host immunity including the role of sex hormones. We then outline the potential effects of these differences on HIV persistence, and on the safety and efficacy of HIV eradication and curative interventions. Finally, we discuss the next steps necessary to elucidate these factors to achieve a cure for HIV, taking in account the complex ethical issues and the regulatory landscape in the hopes of stimulating further research and awareness in these areas.

Conclusions

Targeted enrolment of women in clinical trials and careful sex-based analysis will be crucial to gain further insights into sex-based differences in HIV persistence and to design sex-specific approaches to HIV eradication, if required.

Effects on pulmonary rehabilitation in patients with COPD or ILD: A retrospective analysis of clinical and functional predictors with particular emphasis on gender

BACKGROUND

The response of patients in a pulmonary rehabilitation (PR) is essentially good. However, not all patients benefit from PR to the same extent. In this analysis we wanted to identify the impact of gender and other factors on PR outcomes in patients with chronic obstructive pulmonary disease (COPD) or interstitial lung disease (ILD).

METHODS

Patients suffering from COPD (n = 1492) or ILD (n = 599), treated during an inpatient PR between 1997 and 2015, were analysed according to the effects of PR on exercise capacity and quality of life with regard to the impact of gender or other predictors by univariate and multivariate analyzes.

RESULTS

In the group of COPD patients, 30% did not achieve the expected physical performance during the 6-min walk test (28% of female and 32% of male patients). However, the non-responders initially have had a higher 6-min walking distance (6-MWD) (p < 0.001) and both male and female showed a significant lower BODE index (p = 0.025) in the multivariate analysis. In the ILD-group, 37% females and 43% males were classified as non-responders with regard to the 6-MWD. Also in this group, the non-responders initially have had a higher 6-MWD (p < 0.001). All other variables (age, BMI, lung function, blood gases, C-reactive Protein, Haemoglobin or rehabilitation duration) had no influence on the outcome.

CONCLUSION

Our study supports the positive effects of PR in COPD and ILD patients. In both groups, patients with the biggest limitations benefit most from PR. However, relevant gender differences or other predictors could not be found.

Systematic Analysis of Sex-Linked Molecular Alterations and Therapies in Cancer

Though patient sex influences response to cancer treatments, little is known of the molecular causes, and cancer therapies are generally given irrespective of patient sex. We assessed transcriptomic differences in tumors from men and women spanning 17 cancer types, and we assessed differential expression between tumor and normal samples stratified by sex across 7 cancers. We used the LincsCloud platform to perform Connectivity Map analyses to link transcriptomic signatures identified in male and female tumors with chemical and genetic perturbagens, and we performed permutation testing to identify perturbagens that showed significantly differential connectivity with male and female tumors. Our analyses predicted that females are sensitive and males are resistant to tamoxifen treatment of lung adenocarcinoma, a finding which is consistent with known male-female differences in lung cancer. We made several novel predictions, including that CDK1 and PTPN1 knockdown would be more effective in males with hepatocellular carcinoma, and SMAD3 and HSPA4 knockdown would be more effective in females with head and neck squamous cell carcinoma. Our results provide a new resource for researchers studying male-female biological and treatment response differences in human cancer. The complete results of our analyses are provided at the website accompanying this manuscript (http://becklab.github.io/SexLinked).

Excess maternal salt or fructose intake programmes sex-specific, stress- and fructose-sensitive hypertension in the offspring

The Western diet is typically high in salt and fructose, which have pressor activity. Maternal diet can affect offspring blood pressure, but the extent to which maternal intake of excess salt and fructose may influence cardiovascular function of the offspring is unknown. We sought to determine the effect of moderate maternal dietary intake of salt and/or fructose on resting and stimulated cardiovascular function of the adult male and female offspring. Pregnant rats were fed purified diets (±4 % salt) and water (±10 % fructose) before and during gestation and through lactation. Male and female offspring were weaned onto standard laboratory chow. From 9 to 14 weeks of age, cardiovascular parameters (basal, circadian and stimulated) were assessed continuously by radiotelemetry. Maternal salt intake rendered opposite-sex siblings with a 25-mmHg difference in blood pressure as adults; male offspring were hypertensive (15 mmHg mean arterial pressure (MAP)) and female offspring were hypotensive (10 mmHg MAP) above and below controls, respectively. Sex differences were unrelated to endothelial nitric oxide activity in vivo, but isolation-induced anxiety revealed a significantly steeper coupling between blood pressure and heart rate in salt-exposed male offspring but not in female offspring. MAP of all offspring was refractory to salt loading but sensitive to subsequent dietary fructose, an effect exacerbated in female offspring from fructose-fed dams. Circadian analyses of pressure in all offspring revealed higher mean set-point for heart rate and relative non-dipping of nocturnal pressure. In conclusion, increased salt and fructose in the maternal diet has lasting effects on offspring cardiovascular function that is sex-dependent and related to the offspring’s stress–response axis.

Sex-specific analysis of data in high-impact orthopaedic journals: how are we doing?

BACKGROUND

In 2001, the Institute of Medicine released a report stating that sex must be considered in all aspects and at all levels of biomedical research. Knowledge of differences between males and females in responses to treatment serves to improve our ability to care for our patients.

QUESTIONS/PURPOSES

The purpose of our study was to determine (1) if there is an increase in the proportion of sex-specific reporting from 2000 to 2005 and to 2010; and (2) whether there is a proportional difference in such reporting based on journal type: subspecialty versus general orthopaedics. We hypothesize that assessment of the role of sex in outcomes has improved during the past 15 years and that the proportion of studies with of sex-specific analyses has increased with awareness of the role of sex in clinical outcomes and disease states. We additionally hypothesized that the reporting of sex would be similar between subspecialty and general orthopaedic journals.

METHODS

Five high-impact orthopaedic journals, consisting of two general and three subspecialty journals, were chosen for review. Issues from even-numbered months during three calendar years (2000, 2005, 2010) were critically assessed for the presence of sex-specific analyses and reporting by two separate reviewers. Retrospective and prospective clinical studies, with a minimum of 20 patients, were included for analysis. Cadaveric, biomechanical, and in vitro studies were excluded. Review articles and clinical studies with less than 20 patients were excluded. A total of 821 studies that met inclusion criteria were analyzed: 206 in 2000, 277 in 2005, and 338 in 2010.

RESULTS

Overall, the proportion of sex-specific analyses increased during the three times studied (19%, 40/206, [95% CI, 0.14-0.25] of the studies in 2000; 27%, 77/277, [95% CI, 0.23-0.33] in 2005; and 30%, 102/338, [95% CI, 0.25-0.35] in 2010). The increase in the proportion of sex-specific analysis was significant between 2000 and 2005 (p = 0.033), but was not significant between 2005 and 2010 (p = 0.518). During each of the three specific years studied, general and subspecialty journals increased in the proportions that reported sex-based analyses, but specialty journals had significantly higher reporting rates only in 2000 (2000: 11.9%, 13/109, [95% CI, 0.06-0.18] and 27.8%, 27/97, [95% CI, 0.19-0.37], p = 0.004; 2005: 22.9%, 33/144, [95% CI, 0.16-0.30], and 33.1%, 44/133, [95% CI, 0.25-0.41], p = 0.059; 2010: 28.2%, 51/181, [95% CI, 0.22-0.35] and 32.5%, 51/157, [95% CI, 0.25-0.40], p = 0.390).

CONCLUSIONS

Our findings indicate that inclusion of sex-specific analysis and reporting in the orthopaedic literature improved during our study period, but are present in less than 1/3 of the studies. Although subgroup analysis and reporting are required by NIH guidelines, it is important that such analyses be published in non-NIH-funded studies to generate hypotheses regarding sex differences for subsequent research. These data also are important as they can be used in systematic reviews where large independent studies may not be available in the literature.

CLINICAL RELEVANCE

Where evaluating conditions that affect males and females, studies should be designed with sufficient sample size to allow for subgroup analysis by sex to be performed, and they should include sex-specific differences among the a priori research questions.

Sex-specific regulation of chemokine Cxcl5/6 controls neutrophil recruitment and tissue injury in acute inflammatory states

BACKGROUND

Tissue infiltration by neutrophils during acute inflammatory states causes substantial tissue injury. While the magnitude of tissue neutrophil accumulation in innate immune responses is profoundly greater in males than females, fundamental aspects of the molecular mechanisms underlying these sex differences remain largely unknown.

METHODS

We investigated sex differences in neutrophil stimulation and recruitment in ischemia/reperfusion (I/R; mesenteric or renal) or carrageenan pleurisy in rats or mice, as well as skin injury in human volunteers. The induction of potent chemoattractive mediators (chemokines) and neutrophil adhesion molecules were measured by real-time PCR, flow cytometry, and protein assays.

RESULTS

Mesenteric I/R in age-matched Wistar rats resulted in substantially more neutrophil accumulation and tissue injury at 2 h reperfusion in males than females. Using intravital microscopy, we show that the immediate (<30 min) neutrophil response to I/R is similar in males and females but that prolonged neutrophil recruitment occurs in males at sites local and distal to inflammatory insult partly due to an increase in circulating neutrophil populations with elevated surface expression of adhesion molecules. Sex differences in neutrophil kinetics were correlated with sustained induction of chemokine Cxcl5 in the tissue, circulation, and bone marrow of males but not females. Furthermore, blockade of Cxcl5 in males prior to ischemia resulted in neutrophil responses that were similar in magnitude to those in females. Conversely, administration of Cxcl5 to males in the absence of I/R was sufficient to increase levels of systemic neutrophils. Cxcl5 treatment of bone marrow neutrophils in vitro caused substantial induction of neutrophil-mobilizing cytokine granulocyte colony-stimulating factor (GCSF) and expression of β2 integrin that accounts for sexual dimorphism in circulating neutrophil populations in I/R. Moreover, male Cxcl5-stimulated bone marrow neutrophils had an increased capacity to adhere to β2 integrin ligand ICAM-1, implicating a greater sensitivity of male leukocytes to Cxcl5-mediated activation. Differential induction of Cxcl5 (human CXCL6) between the sexes was also evident in murine renal I/R, rat pleurisy, and human skin blisters and correlated with the magnitude of neutrophil accumulation in tissues.

CONCLUSIONS

Our study reveals that sex-specific induction of chemokine Cxcl5/CXCL6 contributes to sexual dimorphism in neutrophil recruitment in diverse acute inflammatory responses partly due to increased stimulation and trafficking of bone marrow neutrophils in males.

Characterization of whole-genome autosomal differences of DNA methylation between men and women

Background

Disease risk and incidence between males and females reveal differences, and sex is an important component of any investigation of the determinants of phenotypes or disease etiology. Further striking differences between men and women are known, for instance, at the metabolic level. The extent to which men and women vary at the level of the epigenome, however, is not well documented. DNA methylation is the best known epigenetic mechanism to date.

Results

In order to shed light on epigenetic differences, we compared autosomal DNA methylation levels between men and women in blood in a large prospective European cohort of 1799 subjects, and replicated our findings in three independent European cohorts. We identified and validated 1184 CpG sites to be differentially methylated between men and women and observed that these CpG sites were distributed across all autosomes. We showed that some of the differentially methylated loci also exhibit differential gene expression between men and women. Finally, we found that the differentially methylated loci are enriched among imprinted genes, and that their genomic location in the genome is concentrated in CpG island shores.

Conclusion

Our epigenome-wide association study indicates that differences between men and women are so substantial that they should be considered in design and analyses of future studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13072-015-0035-3) contains supplementary material, which is available to authorized users.

Low-carbohydrate, high-fat diets have sex-specific effects on bone health in rats

PURPOSE

Studies in humans suggest that consumption of low-carbohydrate, high-fat diets (LC-HF) could be detrimental for growth and bone health. In young male rats, LC-HF diets negatively affect bone health by impairing the growth hormone/insulin-like growth factor axis (GH/IGF axis), while the effects in female rats remain unknown. Therefore, we investigated whether sex-specific effects of LC-HF diets on bone health exist.

METHODS

Twelve-week-old male and female Wistar rats were isoenergetically pair-fed either a control diet (CD), "Atkins-style" protein-matched diet (LC-HF-1), or ketogenic low-protein diet (LC-HF-2) for 4 weeks. In females, microcomputed tomography and histomorphometry analyses were performed on the distal femur. Sex hormones were analysed with liquid chromatography-tandem mass spectrometry, and endocrine parameters including GH and IGF-I were measured by immunoassay.

RESULTS

Trabecular bone volume, serum IGF-I and the bone formation marker P1NP were lower in male rats fed both LC-HF diets versus CD. LC-HF diets did not impair bone health in female rats, with no change in trabecular or cortical bone volume nor in serum markers of bone turnover between CD versus both LC-HF diet groups. Pituitary GH secretion was lower in female rats fed LC-HF diet, with no difference in circulating IGF-I. Circulating sex hormone concentrations remained unchanged in male and female rats fed LC-HF diets.

CONCLUSION

A 4-week consumption of LC-HF diets has sex-specific effects on bone health-with no effects in adult female rats yet negative effects in adult male rats. This response seems to be driven by a sex-specific effect of LC-HF diets on the GH/IGF system.