Sex-related differences in the intratubular renin-angiotensin system in two-kidney, one-clip hypertensive rats

The intratubular renin-angiotensin system (RAS) is thought to play an essential role in hypertensive renal disease, but information regarding sex-related differences in this system is limited. The present study investigated sex differences in the intratubular RAS in two-kidney, one-clip (2K1C) rats. A 2.5-mm clip was placed on the left renal artery of Sprague-Dawley rats, and rats were euthanized 3 or 5 wk after the operation. Systolic blood pressure increased in 2K1C rats in both sexes but was significantly higher in male rats than in female rats, and an antihypertensive effect was not observed in 2K1C ovariectomized (OVX) female rats. Compared with male 2K1C rats, intratubular angiotensin-converting enzyme (ACE) and ANG II were repressed, and intratubular ACE2, angiotensin (1-7), and Mas receptor were increased in both kidneys in female 2K1C rats 5 wk after surgery. Comparison with male and female rats and intratubular mRNA levels of ACE and ANG II type 1 receptor were augmented in OVX female rats, regardless of the clipping surgery 3 wk postoperation. ANG II type 2 receptor was upregulated in female rats with or without OVX; thus, the ANG II type 1-to-type 2 receptor ratio was higher in male rats than in female rats. In conclusion, female rats were protected from hypertensive renal and cardiac injury after renal artery clipping. An increase in the intratubular nonclassic RAS [ACE2/angiotensin (1-7)/Mas receptor] and a decrease in the ANG II type 1-to-type 2 receptor ratio could limit the adverse effects of the classic RAS during renovascular hypertension in female rats, and estrogen is suggested to play a primary role in the regulation of intratubular RAS components.

Sex-related differences in symptoms of temporomandibular disorders and structural changes in the lateral pterygoid muscle after whiplash injury

Whiplash injury is an initiating or aggravating factor of temporomandibular disorder (TMD). Although there are sex-related differences in the mechanism of pain perception and pain control, there is a lack of research on differences in TMD after whiplash injury. We aimed to evaluate sex-related differences in the clinical symptoms and magnetic resonance imaging (MRI) findings of patients with TMD attributed to whiplash injury. This retrospective, cross-sectional study included 100 patients (50 women; 50 men; mean age, 37.60 years) who visited our oro-facial pain clinic with symptoms of TMD after whiplash injury. All patients underwent detailed evaluations for history of trauma, and their clinical and MRI findings were comprehensively assessed. Women with TMD after whiplash injury perceived more pain and presented more tenderness upon palpation than did men with TMD. In addition, women showed higher volume (58% vs 26%) and signal changes (54% vs 20%) in the lateral pterygoid muscle (LPM) and more anterior disc displacement without reduction (ADDWoR) (40% vs 20%) than did men. The presence of ADDWoR (odds ratio, 10.58; P = 0.007) and condylar degeneration (odds ratio, 9.30; P = 0.015) predicted LPM volume; stressful conditions (beta = 1.34; P = 0.011) correlated with increased visual analogue scale scores, and sleep problem was associated with an increased palpation index (PI) (beta = 0.42; P < 0.001) and neck PI (beta = 0.49; P < 0.001) scores only in women. Our results showed sex-specific differences in pain intensity, distribution of clinical and abnormal MRI findings, and their relationships, and these differences should be considered when treating patients with TMD.

Sex-dependent effects of early unstable post-natal environment on response to positive and negative stimuli in adult mice

Alterations in early environmental conditions that interfere with the creation of a stable mother-pup bond have been suggested to be a risk factor for the development of stress-related psychopathologies later in life. The long-lasting effects of early experiences are mediated by changes in various cerebral circuits, such as the corticolimbic system, which processes aversive and rewarding stimuli. However, it is evident that the early environment is not sufficient per se to induce psychiatric disorders; interindividual (eg, sex-based) differences in the response to environmental challenges exist. To examine the sex-related effects that are induced by an early experience on later events in adulthood, we determine the enduring effects of repeated cross-fostering (RCF) in female and male C57BL/6J mice. To this end, we assessed the behavioral phenotype of RCF and control (male and female) mice in the saccharine preference test and cocaine-induced conditioned place preference to evaluate the response to natural and pharmacological stimuli and in the elevated plus maze test and forced swimming test to measure their anxiety- and depression-like behavior. We also evaluated FST-induced c-Fos immunoreactivity in various brain regions that are engaged in the response to acute stress exposure (FST). Notably, RCF has opposing effects on the adult response to these tests between sexes, directing male mice toward an "anhedonia-like" phenotype and increasing the sensitivity for rewarding stimuli in female mice.

Multilevel Mapping of Sexual Dimorphism in Intrinsic Functional Brain Networks

Differences in cognitive performance between males and females are well-described, most commonly in certain spatial and language tasks. Sex-related differences in cognition are relevant to the study of the neurotypical brain and to neuropsychiatric disorders, which exhibit prominent disparities in the incidence, prevalence and severity of symptoms between men and women. While structural dimorphism in the human brain is well-described, controversy exists regarding the existence and degree of sex-related differences in brain function. We analyzed resting-state functional MRI from 650 neurotypical young adults matched for age and sex to determine the degree of sexual dimorphism present in intrinsic functional networks. Multilevel modeling was pursued to create 8-, 24-, and 51-network models of whole-brain data to quantify sex-related effects in network activity with increasing resolution. We determined that sexual dimorphism is present in the majority of intrinsic brain networks and affects ∼0.5-2% of brain locations surveyed in the three whole-brain network models. It is particularly common in task-positive control networks and is pervasive among default mode networks. The size of sex-related effects varied by network but can be moderate or even large in size. Female > male effects were on average larger, but male > female effects spread across greater network territory. Using a novel methodology, we mapped dimorphic locations to meta-analytic association test maps derived from task fMRI, demonstrating that the neurocognitive footprint of intrinsic neural correlates is much larger in males. All results were replicated in a motion-matched sub-sample. Our findings argue that sex is an important biological variable in human brain function and suggest that observed differences in neurocognitive performance have identifiable intrinsic neural correlates.

Sex Hormones and Optic Nerve Disorders: A Review

Aim: This review article presents a comprehensive overview of the literature on sex hormones (estrogens, androgens, progesterone) and optic nerve disorders, with a discussion of the implications for therapy and prevention.

Methods: Epidemiological, pre-clinical and clinical studies were reviewed.

Results: Analysis of the biological basis for a relationship between eye diseases and sex hormones showed that some types of hormones can exert a protective effect either directly on the retina and optic nerve or indirectly by modulating ocular blood flow. For example, it seems that estrogen exposure has a protective effect against glaucoma, whereas its deficit may lead to early onset of the disease. If further studies confirm the data in the literature, estrogen therapy, because of its antioxidant action, may be effective in the treatment of Leber's hereditary optic neuropathy, whereas, in the light of current studies, there does not seem to be an influence of estrogen on non-arteritic anterior ischemic optic neuritis (NAION).

Conclusions: Although there is some evidence that in some optic nerve pathologies the sex hormones seem to play an important role there are still too few studies providing evidence for its wider use in clinical practice.

Sex-related differences in frailty factors in older persons with type 2 diabetes: a cross-sectional study

BACKGROUND

This cross-sectional study aimed to describe sex-related differences in diabetes-specific factors underlying the development of frailty in older persons with type 2 diabetes.

METHODS

Older persons aged 60-80 years were sequentially enrolled. Frailty and sarcopenia were evaluated using the validated Kihon checklist (KCL) and Asian Working Group for Sarcopenia algorithm, respectively. Physical function and characteristics were measured by trained nurses independently.

RESULTS

This study included 213 participants. The mean age, body mass index (BMI), and glycated hemoglobin (HbA1c) level were 70.4 years, 24.3 kg/m², and 7.4%, respectively. Prevalence of frailty was higher in women. Social and cognitive functions were lower in the prefrailty stage, while physical function was lower in the frailty stage, although there was no decrease in skeletal muscle mass. After adjustment for age, the KCL score was significantly associated with peripheral neuropathy, diet score, and coronary artery disease (CAD); frailty, with CAD and inoccupation; prefrailty, with diet score; and sarcopenia, with living alone in men. Meanwhile, the KCL score was significantly associated with living alone and skeletal muscle percentage; prefrailty, with peripheral neuropathy; and sarcopenia, with diabetes duration, LDL-cholesterol level, diet score, and irregular lifestyle in women.

CONCLUSIONS

Sex differences in the risk factors of frailty should be considered when selecting preventive strategies for older persons with type 2 diabetes, early in the prefrailty stage. In particular, it is important to evaluate social participation and diet therapy in men and skeletal muscle mass and psychosocial function in women.

Sex-related differences in fuel utilization and hormonal response to exercise: implications for individuals with type 1 diabetes

Sex-related differences in metabolic and neuroendocrine response to exercise in individuals without diabetes have been well established. Men and women differ in fuel selection during exercise, in which women rely to a greater extent on fat oxidation, whereas males rely mostly on carbohydrate oxidation for energy production. The difference in fuel selection appears to be mediated by sex-related differences in hormonal (including catecholamines, growth hormone, and estrogen) response to different types and intensities of exercise. In general, men exhibit an amplified counter-regulatory response to exercise, with elevated levels of catecholamines compared with women. However, women exhibit greater sensitivity to the lipolytic action of the catecholamines and deplete less of their glycogen stores than men during exercise, which suggests that women may experience a greater defense in blood glucose control after exercise than men. Conversely, little is known about sex-related differences in response to exercise in individuals with type 1 diabetes (T1D). A single study investigating sex-related differences in response to moderate aerobic exercise in individuals with T1D found sex-related differences in catecholamine response and fuel selection, but changes in blood glucose were not measured. To our knowledge, there are no studies investigating sex-related differences in blood glucose responses to different types and intensities of exercise in individuals with T1D. This review summarizes sex-related differences in exercise responses that could potentially impact blood glucose levels during exercise in individuals with T1D and highlights the need for further research.

Gonadal Hormones and Retinal Disorders: A Review

AIM

Gonadal hormones are essential for reproductive function, but can act on neural and other organ systems, and are probably the cause of the large majority of known sex differences in function and disease. The aim of this review is to provide evidence for this hypothesis in relation to eye disorders and to retinopathies in particular.

METHODS

Epidemiological studies and research articles were reviewed.

RESULTS

Analysis of the biological basis for a relationship between eye diseases and hormones showed that estrogen, androgen, and progesterone receptors are present throughout the eye and that these steroids are locally produced in ocular tissues. Sex hormones can have a neuroprotective action on the retina and modulate ocular blood flow. There are differences between the male and the female retina; moreover, sex hormones can influence the development (or not) of certain disorders. For example, exposure to endogenous estrogens, depending on age at menarche and menopause and number of pregnancies, and exposure to exogenous estrogens, as in hormone replacement therapy and use of oral contraceptives, appear to protect against age-related macular degeneration (both drusenoid and neurovascular types), whereas exogenous testosterone therapy is a risk factor for central serous chorioretinopathy. Macular hole is more common among women than men, particularly in postmenopausal women probably owing to the sudden drop in estrogen production in later middle age. Progestin therapy appears to ameliorate the course of retinitis pigmentosa. Diabetic retinopathy, a complication of diabetes, may be more common among men than women.

CONCLUSION

We observed a correlation between many retinopathies and sex, probably as a result of the protective effect some gonadal hormones may exert against the development of certain disorders. This may have ramifications for the use of hormone therapy in the treatment of eye disease and of retinal disorders in particular.

Sex-related differences in bronchial parameters and pulmonary function test results in patients with chronic obstructive pulmonary disease based on three-dimensional quantitative computed tomography

Objective

This study was performed to evaluate the effect of sex on bronchial parameters and the predicted forced expiratory volume in 1 s expressed as a percentage of the forced vital capacity (FEV1% pred) on pulmonary function testing.

Methods

The data of 359 patients with chronic obstructive pulmonary disease (COPD) with available FEV1% pred and computed tomography (CT) images were retrospectively reviewed. FACT-Digital lung TM software (DeXin, Xi’an, China) was used to perform fully automated three-dimensional CT quantitative measurements of the bronchi. Generation 5 to 7 bronchi were measured, and the parameters analyzed were the lumen diameter (LD), wall thickness (WT), lumen area (LA), and WA% [WA / (WA + LA) × 100%].

Results

In the smoking, smoking cessation, and nonsmoking groups, women had a significantly larger WA% and smaller LD, WT, and LA than men. The FEV1% pred was significantly lower in women than men in the smoking and smoking cessation groups. The FEV1% pred was significantly higher in women than men in the nonsmoking group.

Conclusion

Sex-related differences may partially explain why smoking women experience more severe pulmonary function impairment than men among patients with COPD.

Sex-related differences in autoimmune-induced lung lesions in MRL/MpJ-faslpr mice are mediated by the development of mediastinal fat-associated lymphoid clusters

MRL/MpJ-Fas^lpr (lpr) mice are a model for autoimmune diseases such as systemic lupus erythematosus (SLE). These diseases mainly affect women, with a 10:1 female-to-male ratio, and cause pleuropulmonary lesions. We previously revealed a correlation between mediastinal fat-associated lymphoid cluster (MFALC) development and cellular infiltration in the lungs of lpr male mice; however, we did not report on MFALCs in females. The purpose of this investigation was to reveal sex-related differences in MFALCs in lpr mice. We compared the morphological features of MFALCs and lung mononuclear cell aggregates (LMCAs) in 5-month-old male and female lpr mice. The females showed significantly elevated anti-dsDNA autoantibody titers and larger MFALCs, with a higher ratio of lymphatic vessel (LV) and high endothelial venule (HEV) areas to MFALC area, and greater numbers of T- and B-cells, macrophages, and proliferating and dendritic cells in MFALCs and LMCAs than males. Our data indicated that MFALCs were more developed and lung lesions were more severe in female than in male lpr mice, thereby suggesting a potential role for LVs and HEVs in the establishment of MFALCs and lung lesions. Further investigation in female lpr mice will be needed for treatment of human respiratory diseases and autoimmune disorders.

Sex-Related Characteristics of Systemic Hormonal Homeostasis in Rats with Sarcoma C-45 Cells Transplanted to the Lung

Sex-related systemic status of pituitary and thyroid hormones and cortisol was studied in rats on days 7 and 14 after transplantation of sarcoma C-45 cells into the lung. Females demonstrated slower development of the tumor process (49.0±10.7 vs. 32.0±3.9 days in males). Injection of tumor cells causes similar disorders in the levels of ACTH, thyrotropic hormone, and prolactin in males and females and opposite disorders in the thyroid and glucocorticoid homeostasis associated in males (in contrast to females) with reduction of cortisol level (by 1.9 times) and increase in the concentrations of total thyroxine forms (by 1.4 times) and triiodothyronine (by 2.9 times) by day 14. Early sex-related shifts in the status of hormone that are a component of the adaptive system attest to their possible relationship with different course of the malignant process in male and female rats.

How else can we study sex differences in early infancy?

This paper revisits group difference and individual variability in birth weight, head size, Apgar score, and motor performance in neonatal and 8-month-old males and females using a large existing data set. The goal is primarily theoretical--to reframe existing analyses with an eye toward designing and executing more predictive analyses in the future. 3D graphing to visualize both the areas of overlap and regions of disparity between boys and girls has been used. A two-step cluster analysis of boys and girls together revealed three clusters. One was almost equally divided between boys and girls, but a second was highly enriched for boys and the third highly skewed toward girls. The relationship between cluster membership and Bayley motor scores at 8 months tested the hypothesis that initial differences that have no sex-related behavioral content might start processes that produce later sex-related differences. Initially, parental belief systems may be less important than infant care patterns evoked by basic size and health characteristics, even though later parental behaviors assume a decidedly gendered pattern.

Sex-related differences in baseline characteristics, management and outcome in patients with acute coronary syndrome without ST-segment elevation

AIM

To detect sex-related differences in baseline characteristics, management and outcome in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

METHODS

Data from 812 consecutive patients admitted to our cardiology department for NSTE-ACS between 2001 and 2004 were obtained. Early invasive therapy was defined as revascularization during first hospital stay. A seven-year follow-up for the clinical endpoint of all-cause mortality could be obtained in 342 women and 440 men, respectively.

RESULTS

Compared with men, women were significantly older and more likely to suffer from renal insufficiency. The proportion treated with clopidogrel at admission was 43.6% for women and 52.7% for men, respectively (p=0.011). Significantly fewer women underwent an early invasive therapy compared with men (27.5% vs. 35.2%; p=0.021). Age and renal insufficiency were the strongest predictors for a conservative approach in both female and male patients. After adjustment for baseline characteristics there was no significant difference in treatment between women and men (odds ratio 0.89; 95% confidence interval 0.59-1.35; p=0.588). While in-hospital mortality was similar between the sexes, long-term mortality was significantly higher in women compared with men (8.2% vs. 7.0%; p=0.549 for in-hospital mortality and 54.8% vs. 39.3%; p<0.001 for seven-year mortality). However, after adjustment for baseline characteristics and treatment there was no significant difference in long-term mortality between women and men (hazard ratio 1.14; 95% confidence interval 0.89-1.47; p=0.307).

CONCLUSION

In these patients with NSTE-ACS women were less likely to undergo an early invasive therapy compared with men due to their higher age and the higher rate of renal insufficiency. After adjustment for age, comorbidities and treatment female sex was not associated with worse long-term outcome.

Sex-Related Differences in Self-Reported Neurocognitive Impairment among High-Risk Cocaine Users in Methadone Maintenance Treatment Program

BACKGROUND

Previous research has suggested possible sex-related differences in executive functioning among cocaine users; however, no studies specifically explain sex-related differences in neurocognitive impairment (NCI) among cocaine users receiving clinical care. Knowledge about this association can aid in the development of targeted prevention strategies to reduce adverse health outcomes. This study was designed to examine the sex-related differences in NCI among high-risk cocaine users receiving substance-abuse treatment.

METHODS

The Neuropsychological Impairment Scale (NIS) was administered to 199 cocaine users (98 men; 101 women), receiving methadone maintainance treatment, to assess self-reported NCI by identifying the patients’ awareness of neuropsychological symptoms. We used T-test comparison to find differences in NCI between men and women and multiple regression analysis to explore the relative contribution of sex to NCI.

RESULTS

Consistent with prior work, high NCI was evident within this sample, as indicated by high scores on most of the NIS subscales. Women reported greater impairment than men, as evidenced by significantly higher scores on several NIS subscales, after controlling for demographic and other confounding variables. Interestingly, cocaine craving significantly predicted NCI among men but not among women, as suggested by the significant association between cocaine craving and all except one of the NIS subscales.

CONCLUSIONS

These findings suggest that cocaine users enter into treatment with a range of NCI – with women having significantly more neurocognitive deficits than men – that may contribute to differential treatment outcomes. This highlights the need to include additional services such as neuropsychological screening and sex-specific treatment programs to optimally reduce adverse health outcomes in these high-risk, cognitively impaired patients.

Structural composition of myocardial infarction scar in middle-aged male and female rats: does sex matter?

The present study was designed to determine whether the structural composition of the scar in middle-aged post-myocardial infraction (MI) rats is affected by the biological sex of the animals. A large MI was induced in 12-month-old male (M-MI) and female (F-MI) Sprague-Dawley rats by ligation of the left coronary artery. Four weeks after the MI, rats with transmural infarctions, greater than 50% of the left ventricular (LV) free wall, were evaluated. The extent of LV remodeling and fractional volumes of fibrillar collagen (FC), myofibroblasts, vascular smooth muscle (SM) cells, and surviving cardiac myocytes (CM) in the scars were compared between the two sexes. The left ventricle of post-MI male and female rats underwent a similar degree of remodeling as evidenced by the analogous scar thinning ratio (0.46 ± 0.02 vs. 0.42 ± 0.05) and infarct expansion index (1.06 ± 0.07 vs. 1.12 ± 0.08), respectively. Most important, the contents of major structural components of the scar revealed no evident difference between M-MI and F-MI rats (interstitial FC, 80.74 ± 2.08 vs. 82.57 ± 4.53; myofibroblasts, 9.59 ± 1.68 vs.9.56 ± 1.15; vascular SM cells, 2.27 ± 0.51 vs. 3.38 ± 0.47; and surviving CM, 3.26 ± 0.39 vs. 3.05 ± 0.38, respectively). Our data are the first to demonstrate that biological sex does not influence the structural composition of a mature scar in middle-aged post-MI rats.

Sex-based disparities in liver transplant rates in the United States

We sought to characterize sex-based differences in access to deceased donor liver transplantation. Scientific Registry of Transplant Recipients data were used to analyze n = 78 998 adult candidates listed before (8/1997-2/2002) or after (2/2002-2/2007) implementation of Model for End-Stage Liver Disease (MELD)-based liver allocation. The primary outcome was deceased donor liver transplantation. Cox regression was used to estimate covariate-adjusted differences in transplant rates by sex. Females represented 38% of listed patients in the pre-MELD era and 35% in the MELD era. Females had significantly lower covariate-adjusted transplant rates in the pre-MELD era (by 9%; p < 0.0001) and in the MELD era (by 14%; p < 0.0001). In the MELD era, the disparity in transplant rate for females increased as waiting list mortality risk increased, particularly for MELD scores ≥15. Substantial geographic variation in sex-based differences in transplant rates was observed. Some areas of the United States had more than a 30% lower covariate-adjusted transplant rate for females compared to males in the MELD era. In conclusion, the disparity in liver transplant rates between females and males has increased in the MELD era. It is especially troubling that the disparity is magnified among patients with high MELD scores and in certain regions of the United States.

Cycling efficiency in trained male and female competitive cyclists

The aim of this study was to examine differences in cycling efficiency between competitive male and female cyclists. Thirteen trained male (mean ± SD: 34 ± 8 yr, 74.1 ± 6.0 kg, Maximum Aerobic Power (MAP) 414 ± 40 W, VO2max 61.3 ± 5.4 ml·kg(-1)·min(-1)) and 13 trained female (34 ± 9 yr, 60.1 ± 5.2 kg, MAP 293 ± 22 W, VO2max 48.9 ± 6.1 ml·kg(-1)·min(-1)) competitive cyclists completed a cycling test to ascertain their gross efficiency (GE). Leg and lean leg volume of all cyclists was also measured. Calculated GE was significantly higher in female cyclists at 150W (22.5 ± 2.1 vs 19.9 ± 1. 8%; p < 0.01) and 180W (22.3 ± 1.8 vs 20.4 ± 1.5%; p = 0.01). Cadence was not significantly different between the groups (88 ± 6 vs 91 ± 5 rev·min(-1)). Lean leg volume was significantly lower for female cyclists (4.04 ± 0.5 vs 5.51 ± 0.8 dm(3); p < 0.01) and was inversely related to GE in both groups at 150 and 180W (r = -0.59 and -0.58; p < 0.05). Lean leg volume was shown to account for the differences in GE between the males and females. During an "unloaded "pedalling condition, male cyclists had a significantly higher O2 cost than female cyclists (1.0 ± 0.1 vs 0.7 ± 0.1 L·min(-1); p < 0.01), indicative of a greater non-propulsive cost of cycling. These results suggest that differences in efficiency between trained male and female cyclists can be partly accounted for by sex-specific variation in lean leg volume. Key pointsDifferences in GE exist between male and female cyclists.Males have a higher oxygen cost of "unloaded "cycling, as predicted by the intercept of the O2 cost-power output relationshipThis suggests that in addition to work rate, leg volume/mass may be an important determinant of observed differences in oxygen cost and therefore GE, between male and female competitive cyclists.