Gonadal hormones and stroke risk: PCOS as a case study

Effects of Gender and Vitamin D on Vascular Reactivity of the Carotid Artery on a Testosterone-Induced PCOS Model

The negative cardiovascular effects of polycystic ovary syndrome (PCOS) and vitamin D deficiency (VDD) have been discussed previously; however, the sex differences between PCOS females and males are not yet known. Our aim was to investigate the effect of PCOS and VDD in the carotid artery of male and female Wistar rats. Females were treated with transdermal testosterone (Androgel) for 8 weeks, which caused PCOS. VDD and vitamin D supplementation were accomplished via diet. The carotid arteries' contraction and relaxation were examined using myography. Receptor density was investigated using immunohistochemistry. In PCOS females, angiotensin receptor density, angiotensin II-induced contraction, androgen receptor optical density, and testosterone-induced relaxation increased. The increased contractile response may increase cardiovascular vulnerability in women with PCOS. As an effect of VDD, estrogen receptor density increased in all our groups, which probably compensated for the reduced relaxation caused by VDD. Testosterone-induced relaxation was decreased as a result of VDD in males and non-PCOS females, whereas this reduction was absent in PCOS females. Male sex is associated with increased contraction ability compared with non-PCOS and PCOS females. VDD and Androgel treatment show significant gender differences in their effects on carotid artery reactivity. Both VDD and PCOS result in a dysfunctional vascular response, which can contribute to cardiovascular diseases.

Disruption of Vitamin D Signaling Impairs Adaptation of Cerebrocortical Microcirculation to Carotid Artery Occlusion in Hyperandrogenic Female Mice

Vitamin D deficiency contributes to the pathogenesis of age-related cerebrovascular diseases, including ischemic stroke. Sex hormonal status may also influence the prevalence of these disorders, indicated by a heightened vulnerability among postmenopausal and hyperandrogenic women. To investigate the potential interaction between sex steroids and disrupted vitamin D signaling in the cerebral microcirculation, we examined the cerebrovascular adaptation to unilateral carotid artery occlusion (CAO) in intact, ovariectomized, and hyperandrogenic female mice with normal or functionally inactive vitamin D receptor (VDR). We also analyzed the morphology of leptomeningeal anastomoses, which play a significant role in the compensation. Ablation of VDR by itself did not impact the cerebrocortical adaptation to CAO despite the reduced number of pial collaterals. While ovariectomy did not undermine compensatory mechanisms following CAO, androgen excess combined with VDR inactivity resulted in prolonged hypoperfusion in the cerebral cortex ipsilateral to the occlusion. These findings suggest that the cerebrovascular consequences of disrupted VDR signaling are less pronounced in females, providing a level of protection even after ovariectomy. Conversely, even short-term androgen excess with lacking VDR signaling may lead to unfavorable outcomes of ischemic stroke, highlighting the complex interplay between sex steroids and vitamin D in terms of cerebrovascular diseases.

The aging ovary impairs acute stroke outcomes

In experimental stroke, ovariectomized (OVX) adult rats have larger infarct volumes and greater sensory-motor impairment as compared to ovary-intact females and is usually interpreted to indicate that ovarian hormones are neuroprotective for stroke. Previous work from our lab shows that middle-aged, acyclic reproductively senescent (RS) females have worse stroke outcomes as compared to adult (normally cycling) females. We hypothesized that if loss of ovarian estrogen is the critical determinant of stroke outcomes, then ovary-intact middle-aged acyclic females, who have reduced levels of estradiol, should have similar stroke outcomes as age-matched OVX. Instead, the data demonstrated that OVX RS animals showed better sensory-motor function after stroke and reduced infarct volume as compared to ovary-intact females. Inflammatory cytokines were decreased in the aging ovary after stroke as compared to non-stroke shams, which led to the hypothesis that immune cells may be extravasated from the ovaries post-stroke. Flow cytometry indicated reduced overall T cell populations in the aging ovary after middle cerebral artery occlusion (MCAo), with a paradoxical increase in regulatory T cells (Tregs) and M2-like macrophages. Moreover, in the brain, OVX RS animals showed increased Tregs, increased M2-like macrophages, and increased MHC II + cells as compared to intact RS animals, which have all been shown to be correlated with better prognosis after stroke. Depletion of ovary-resident immune cells after stroke suggests that there may be an exaggerated response to ischemia and possible increased burden of the inflammatory response via extravasation of these cells into circulation. Increased anti-inflammatory cells in the brain of OVX RS animals further supports this hypothesis. These data suggest that stroke severity in aging females may be exacerbated by the aging ovary and underscore the need to assess immunological changes in this organ after stroke.

Network-based drug repurposing for potential stroke therapy

Stroke is the leading cause of death and disability worldwide, with a growing number of incidences in developing countries. However, there are currently few medical therapies for this disease. Emerged as an effective drug discovery strategy, drug repurposing which owns lower cost and shorter time, is able to identify new indications from existing drugs. In this study, we aimed at identifying potential drug candidates for stroke via computationally repurposing approved drugs from Drugbank database. We first developed a drug-target network of approved drugs, employed network-based approach to repurpose these drugs, and altogether identified 185 drug candidates for stroke. To validate the prediction accuracy of our network-based approach, we next systematically searched for previous literature, and found 68 out of 185 drug candidates (36.8 %) exerted therapeutic effects on stroke. We further selected several potential drug candidates with confirmed neuroprotective effects for testing their anti-stroke activity. Six drugs, including cinnarizine, orphenadrine, phenelzine, ketotifen, diclofenac and omeprazole, have exhibited good activity on oxygen-glucose deprivation/reoxygenation (OGD/R) induced BV2 cells. Finally, we showcased the anti-stroke mechanism of actions of cinnarizine and phenelzine via western blot and Olink inflammation panel. Experimental results revealed that they both played anti-stroke effects in the OGD/R induced BV2 cells via inhibiting the expressions of IL-6 and COX-2. In summary, this study provides efficient network-based methodologies for in silico identification of drug candidates toward stroke.

Oral contraceptives and stroke: Foes or friends

Incidents of strokes are increased in young women relative to young men, suggesting that oral contraceptive (OC) use is one of the causes of stroke among young women. Long-term exposures to the varying combinations of estrogen and progestogen found in OCs affect blood clotting, lipid and lipoprotein metabolism, endothelial function, and de novo synthesis of neurosteroids, especially brain-derived 17β-estradiol. The latter is essential for neuroprotection, memory, sexual differentiation, synaptic transmission, and behavior. Deleterious effects of OCs may be exacerbated due to comorbidities like polycystic ovary syndrome, sickle cell anemia, COVID-19, exposures to endocrine disrupting chemicals, and conventional or electronic cigarette smoking. The goal of the current review is to revisit the available literature regarding the impact of OC use on stroke, to explain possible underlying mechanisms, and to identify gaps in our understanding to promote future research to reduce and cure stroke in OC users.

The correlation between testosterone and stroke and the mediating role of blood pressure: The Henan rural cohort study

AIMS

We aimed to investigate the association of serum testosterone with stroke and calculate the proportion explained by blood pressure on this association.

MATERIALS AND METHODS

A total of 6175 subjects were included in this study. Serum testosterone was quantified by liquid chromatography-tandem mass spectrometry. The logistic regression model was used to evaluate the association between serum testosterone and stroke. Linear regression analysis was used to assess the associations of serum testosterone with blood pressure. In addition, mediation analysis was performed to identify the mediation effects of blood pressure on the association of serum testosterone with stroke. Sex-stratified analysis was employed throughout the research.

RESULTS

After adjusting for multiple variables, serum testosterone levels were negatively associated with stroke in males (per 1 unit natural log-transformed, odds ratio (OR) = 0.81, 95% confidence interval (CI): 0.69-0.94; Tertile 3 vs Tertile 1, OR = 0.65, 95% CI:0.44-0.96). Furthermore, blood pressure played a partial mediating role in the relationship between testosterone and stroke in males. The indirect effect/total effect of systolic blood pressure, diastolic blood pressure and mean arterial pressure were 7.37%, 9.54% and 9.22%, respectively. Notably, the relationship between testosterone and stroke and the role of blood pressure in regulating them was not observed in females.

CONCLUSION

This study describes that in rural Chinese males, testosterone can reduce the risk of stroke by affecting blood pressure. To some extent, we provide a new epidemiological evidence for the relationship between testosterone and stroke.

Mediating effects of sleep duration on the association between natural menopause and stroke risk among Chinese women

Background

Sleep disturbance is commonly reported by menopausal women. Stroke risk and poor stroke outcomes in women have usually been attributed to menopause. This study aimed to investigate the mediating effect of sleep duration on relationship between menopause and risk of stroke in natural menopause women.

Materials and methods

A cross-sectional study was performed, and participants were recruited through a multistage, stratified, probability proportional to size sampling method in this research. The stroke risk was measured using the risk assessment form for high-risk stroke population. The average sleep duration was calculated by adding up night sleep and afternoon nap duration. Multivariate regression analysis was conducted to identify the association between menopause, sleep duration, and stroke risk. The direct and indirect effects of menopause on stroke risk were analyzed by using the sleep duration in a mediation framework.

Results

Perimenopause, menopause, average sleep duration, and night sleep duration were significantly associated with stroke risk (P < 0.001), after adjusting for covariates. Perimenopause and menopause were significantly related to average sleep duration (P < 0.001) and night sleep duration (P < 0.001). The average sleep duration (ab = 0.016, 95% CI: 0.003, 0.030; ab = −0.048, 95% CI: −0.070, −0.027) partially mediated the relationship between menopause and stroke risk. And night sleep duration (ab = 0.024, 95% CI: 0.009, 0.040; ab = −0.054, 95% CI: −0.077, −0.033) played a major mediating role, in which night sleep duration of ≤5 h mediated the link between both perimenopause (ab = 0.707, 95% CI: 0.392, 1.021) and menopause (ab = −0.787, 95% CI: −1.096, −0.478) and stroke risk; both night sleep duration of >8–9 h (ab = 0.079, 95% CI: 0.010, 0.193) and >9 h (ab = 0.379, 95% CI: 0.086, 0.712) had mediating effects on perimenopause and stroke risk.

Conclusion

A significant relationship between menopause and stroke risk factors among natural menopausal status was found in this study. The average sleep duration, especially night sleep duration, partially mediated the association between menopause and stroke risk, which is a novel insight to the progression of stroke risk in Women. Suitable prevention methods and interventions for sleep in menopausal women may reduce the risk of stroke.

MiR-383-5p promotes apoptosis of ovarian granulosa cells by targeting CIRP through the PI3K/AKT signaling pathway

PURPOSE

To detect miR-383-5p and cold-inducible RNA binding protein (CIRBP, CIRP) expression in patients with polycystic ovary syndrome (PCOS) and explore the mechanism underlying their effect on apoptosis in ovarian granulosa cells (GCs).

METHODS

GCs were extracted from follicular fluid from 101 patients. MiR-383-5p and CIRP expression were assessed by quantitative real time polymerase chain reaction analysis. Correlation between them was assessed by Spearman correlation analysis. The potential of using miR-383-5p expression for discriminating PCOS and non-PCOS patients was predicted by receiver operating characteristic curve analysis. Proliferation and apoptosis of KGN cells transfected for miR-383-5p overexpression or knockdown was evaluated using cell counting kit-8 assay, flow cytometry, and western blot analysis. CIRP was identified as a direct target of miR-383-5p, and verified by dual-luciferase reporter assay.

RESULTS

The expression level of miR-383-5p was decreased and CIRP mRNA was increased in PCOS patients. The expression of miR-383-5p was correlated negatively with body-mass index, basal luteinizing hormone and testosterone levels, luteinizing hormone/follicle-stimulating hormone ratio, and the number of retrieved and metaphase II oocytes. MiR-383-5p had sufficient potential for prediction of PCOS. There was a negative correlation between the expression of miR-383-5p and CIRP. Overexpression of miR-383-5p enhanced the apoptosis of KGN cells. CIRP reversed the effect of miR-383-5p on promotion of apoptosis. MiR-383-5p mimics could suppress the PI3K/AKT signaling pathway, which was activated by the CIRP overexpressing plasmid.

CONCLUSIONS

MiR-383-5p promoted apoptosis of ovarian GCs through the PI3K/AKT signaling pathway by targeting CIRP.

Effects of female obesity on conception, pregnancy and the health of offspring

As we all know, female obesity has become a global epidemic, which is usually accompanied with endocrine and metabolic disorders. Obese women are more likely to experience reproductive problems, including infertility, embryonic developmental defects and abnormality in offspring. Female obesity is a complex multifactorial condition, where there are many mechanisms involved in the effects of overweight and obesity on the development of these reproductive disorders. The insulin resistance, hyperinsulinaemia and hyperandrogenism, lipotoxicity and inflammation are important mechanisms. However, the precise mechanism concerning their correlation is still unclear. Fortunately, weight loss methods have been found to reverse the effects of maternal obesity on the fertility, fetus and offspring.

Significant Increase of Erectile Dysfunction in Men With Post-stroke: A Comprehensive Review

Men with erectile dysfunction (ED) are considered to be at risk from stroke events. Conversely, post-stroke patients are also at high risk of ED, whereas a quantitative result from all the relevant studies has not been previously addressed. Therefore, we have performed a comprehensive review and meta-analysis on this issue. This study was registered on PROSPERO (ID No. CRD42021226618). Twenty studies with a total of 3,382 stroke events were included, of which six studies were included for quantitative analysis, and the remaining 14 studies were calculated for the ratio of ED. Synthetic results from four eligible studies providing the ED cases showed that stroke patients were associated with a significantly higher risk of ED than the general population [pooled relative risk (RR) = 3.32, 95% confidence interval (CI): 1.25–8.82, P = 0.016]. Men with stroke were also found to be associated with a significant decline in International Index of Erectile Function −5 (IIEF-5) score as compared with the healthy controls [three studies, standard mean differences (SMD) = −1.8, 95% CI: −2.94 to −0.67, P = 0.002]. The prevalence of ED in post-stroke patients among 14 studies ranged from 32.1 to 77.8%, which was dramatically higher than that of the general population. The result of the GRADE-pro revealed that the quality of the evidence in this study was moderate. The present study has confirmed the high prevalence of ED in men with stroke. ED in stroke patients is a result of both neurological and psychological factors. Rehabilitative interventions rather than phosphodiesterase-5 (PDE-5) inhibitors are recommended to improve the erectile function for those survivors with ED.