Jayachandran, Muthuvel

Abstract Objective: Development of white matter hyperintensities (WMH) in the brain is associated with blood thrombogenicity in recently menopausal women. This study examined the influence of menopausal hormone treatments (MHTs) on this association. Methods: Measures of blood thrombogenicity were examined in women of the Kronos Early Estrogen Prevention Study (n = 95) who had brain magnetic resonance imaging before and during the 48 months of randomization to transdermal 17β-estradiol (n = 30), oral conjugated equine estrogen (n = 29) both with progesterone for 12 days per month or placebo pills and patch (n = 36). Principal components (PCs) analysis was used to reduce the dimensionality of 14 markers of platelet activation and blood thrombogenicity. The first 5 PCs were assessed for association with treatment and changes in WMH. Within-person slopes were obtained to capture the extent of WMH change for each woman. Results: WMH increased in all groups over the 48 months (P = 0.044). The partial effect of PC1, representing an average of six thrombogenicity variables (microvesicles derived from endothelium, leukocytes, and monocytes, and positive for tissue factor and adhesion molecules) on WMH was significant (P = 0.003). PC3, reflecting a contrast of platelet microaggregates and adenosine triphosphate secretion versus total platelet count, differed across groups (P = 0.006) with higher scores in the oral conjugated equine estrogen group. The global association between PCs and WMH increase, however, did not differ significantly by MHT (P = 0.207 for interaction between MHT and PC's). Conclusion: In recently menopausal women, the type of MHT did not significantly influence the association of markers of blood thrombogenicity with development of WMH in the brain.

Randall’s plaque (RP; subepithelial calcification) appears to be an important precursor of kidney stone disease. However, RP cannot be noninvasively detected. The present study investigated candidate biomarkers associated with extracellular vesicles (EVs) in the urine of calcium stone formers (CSFs) with low (<5% papillary surface area) and high (≥5% papillary surface area) percentages of RP and a group of nonstone formers. RPs were quantitated via videotaping and image processing in consecutive CSFs undergoing percutaneous surgery for stone removal. Urinary EVs derived from cells of different nephron segments of CSFs ( n = 64) and nonstone formers ( n = 40) were quantified in biobanked cell-free urine by standardized and validated digital flow cytometer using fluorophore-conjugated antibodies. Overall, the number of EVs carrying surface monocyte chemoattractant protein (MCP)-1 and neutrophil gelatinase-associated lipocalin (NGAL) were significantly lower in CSFs compared with nonstone former controls ( P < 0.05) but did not differ statistically between CSFs with low and high RPs. The number of EVs associated with osteopontin did not differ between any groups. Thus, EVs carrying MCP-1 and NGAL may directly or indirectly contribute to stone pathogenesis as evidenced by the lower of these populations of EVs in stone formers compared with nonstone formers. Validation of EV-associated MCP-1 and NGAL as noninvasive biomarkers of kidney stone pathogenesis in larger populations is warranted.

AbstractBiological sex and changes in sex hormones throughout life influence all aspects of health and disease. In women, changes in sex hormonal status reflect ovarian function, pregnancy and the use of exogenous hormonal treatments. Longitudinal data from defined cohorts of women will help to identify mechanisms by which the hormonal milieu contributes to cerebrovascular ageing, brain structure and ultimately cognition. This review summarises the phenotypes of three cohorts of women identified through the medical records‐linkage system of the Rochester Epidemiology Project and the Mayo Clinic Specialized Center of Research Excellence (SCORE) on Sex Differences: (i) menopausal women with histories of normotensive or hypertensive pregnancies; (ii) women who had bilateral oophorectomy ≤45 years of age; and (iii) women who experienced natural menopause and used menopausal hormone treatments for 4 years. Data from these cohorts will influence the design of follow‐up studies concerning how sex hormonal status affects neurovascular ageing in women.

Abstract Objective: The Kronos Early Estrogen Prevention Study (KEEPS) was designed to address gaps in understanding the effects of timely menopausal hormone treatments (HT) on cardiovascular health and other effects of menopause after the premature termination of the Women's Health Initiative. Method: The KEEPS was a randomized, double-blinded, placebo-controlled trial to test the hypothesis that initiation of HT (oral conjugated equine estrogens [o-CEE] or transdermal 17β-estradiol [t-E 2 ]) in healthy, recently postmenopausal women ( n = 727) would slow the progression of atherosclerosis as measured by changes in carotid artery intima-media thickness (CIMT). Results: After 4 years, neither HT affected the rate of increase in CIMT. There was a trend for reduced accumulation of coronary artery calcium with o-CEE. There were no severe adverse effects, including venous thrombosis. Several ancillary studies demonstrated a positive effect on mood with o-CEE, and reduced hot flashes, improved sleep, and maintenance of bone mineral density with both treatments. Sexual function improved with t-E 2 . There were no significant effects of either treatment on cognition, breast pain, or skin wrinkling. Variants of genes associated with estrogen metabolism influenced the age of menopause and variability in effects of the HT on CIMT. Platelet activation associated with the development of white matter hyperintensities in the brain. Conclusions: KEEPS and its ancillary studies have supported the value and safety of the use of HT in recently postmenopausal women and provide a perspective for future research to optimize HT and health of postmenopausal women. The KEEPS continuation study continues to pursue these issues.

ABSTRACT The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell‐released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV‐associated functional activities. Finally, a checklist is provided with summaries of key points.

AbstractObjective:Little is known regarding the progression of preclinical atherosclerosis upon cessation of menopausal hormone therapy (MHT). This study evaluated changes in carotid artery intima-media thickness (CIMT) in a subgroup of participants during 4 years and 3 years after the Kronos Early Estrogen Prevention Study (KEEPS).Methods:Of the women enrolled in KEEPS at Mayo Clinic (n = 118), a subset (n = 76) agreed to participate in this follow-up study. KEEPS MHT assignments were placebo (PBO),n = 33; transdermal 17β-estradiol (tE2),n = 23; and oral conjugated equine estrogens group (oCEE),n = 20. CIMT was measured by B-mode ultrasonography. Longitudinal analysis of CIMT was performed using all available data from pre-, on-, and post-treatment periods.Results:At 7 years, median age of participants was 60.2 years; median time since menopause was 8.5 years. The mean difference in rates of increase was significantly greater over the post- than on-treatment period within the oCEE group (0.010 [0.002-0.017] mm/y), but not within the PBO (0.006 [−0.001 to 0.012] mm/y;P = 0.072)or tE2(0.002 [−0.005 to 0.010] mm/y;P = 0.312) groups. There were, however, no significant treatment differences in the linear trends over those intervals (P = 0.524).Conclusions:Cessation of MHT at the lower doses and formulations used in KEEPS did not appear to alter the trajectory of CIMT over a 3-year follow-up period. CIMT, however, increased in all groups over the entire 7-year timeframe as expected with age and timing of menopause possibly key contributors.

Endothelial nitric oxide synthase (eNOS) is regulated both by caveolin-1 and 17β-estradiol (E2). Temporal relationships between effects of estrogen on caveolin-1 and nitric oxide (NO) are not known. Therefore, this study was designed to determine whether estrogen regulates caveolin-1 and, if so, whether such regulation corresponds to changes in nitrite/nitrate (NOx) production. Bovine aortic endothelial cells (BAECs) were cultured in the absence and presence of 17β-estradiol or 17α-estradiol (10−8and 10−10M) for 12, 24, and 48 h. eNOS protein expression and NOxproduction increased significantly after 24 h but not after 12-h treatment with 17β- and not 17α-estradiol. Both mRNA and protein for caveolin-1 were increased significantly only after 48-h treatment with E2, but eNOS protein and NOxproduction were decreased compared with cells treated for 24 h. These increases in caveolin-1 were inhibited by the estrogen receptor antagonist ICI-182,780 (10−6M). Results of this study suggest that E2stimulates caveolin-1 transcription and translation through estrogen receptor-mediated mechanisms. The results further suggest that estrogen may indirectly regulate NOxthrough caveolin-1 expression, which inhibits eNOS catalytic activity.

Cerebrovascular reactivity (CVR) is reduced in patients with cognitive decline. Women with a history of preeclampsia are at increased risk for cognitive decline. This study examined an association between pregnancy history and CVR using a subgroup of 40 age- and parity-matched pairs of women having histories of preeclampsia (n=27) or normotensive pregnancy (n=29) and the association of activated blood elements with CVR. Middle cerebral artery velocity was measured by Doppler ultrasound before and during hypercapnia to assess CVR. Thirty-eight parameters of blood cellular elements, microvesicles, and cell–cell interactions measured in venous blood were assessed for association with CVR using principal component analysis. Middle cerebral artery velocity was lower in the preeclampsia compared with the normotensive group at baseline (63±4 versus 73±3 cm/s; P =0.047) and during hypercapnia ( P =0.013–0.056). CVR was significantly lower in the preeclampsia compared with the normotensive group (2.1±1.3 versus 2.9±1.1 cm·s·mm Hg; P =0.009). Globally, the association of the 7 identified principal components with preeclampsia ( P =0.107) and with baseline middle cerebral artery velocity ( P =0.067) did not reach statistical significance. The interaction between pregnancy history and principal components with respect to CVR ( P =0.084) was driven by a nominally significant interaction between preeclampsia and the individual principal component defined by blood elements, platelet aggregation, and interactions of platelets with monocytes and granulocytes ( P =0.008). These results suggest that having a history of preeclampsia negatively affects the cerebral circulation years beyond the pregnancy and that this effect was associated with activated blood elements.

Renal histologic expression of the podocyte-specific protein, nephrin, but not podocin, is reduced in preeclamptic compared with normotensive pregnancies. We hypothesized that renal expression of podocyte-specific proteins would be reflected in urinary extracellular vesicles (EVs) of podocyte origin and accompanied by increased urinary soluble nephrin levels (nephrinuria) in preeclampsia. We further postulated that podocyte injury and attendant formation of EVs are related mechanistically to cellfree fetal hemoglobin (HbF) in maternal plasma. Our study population included preeclamptic ( n =49) and normotensive ( n =42) pregnant women recruited at delivery. Plasma measurements included HbF concentrations and concentrations of the endogenous chelators haptoglobin, hemopexin, and α 1- microglobulin. We assessed concentrations of urinary EVs containing immunologically detectable podocyte-specific proteins by digital flow cytometry and measured nephrinuria by ELISA. The mechanistic role of HbF in podocyte injury was studied in pregnant rabbits. Compared with urine from women with normotensive pregnancies, urine from women with preeclamptic pregnancies contained a high ratio of podocin-positive to nephrin-positive urinary EVs (podocin + EVs-to-nephrin + EVs ratio) and increased nephrinuria, both of which correlated with proteinuria. Plasma levels of hemopexin, which were decreased in women with preeclampsia, negatively correlated with proteinuria, urinary podocin + EVs-to-nephrin + EVs ratio, and nephrinuria. Administration of HbF to pregnant rabbits increased the number of urinary EVs of podocyte origin. These findings provide evidence that urinary EVs are reflective of preeclampsia-related altered podocyte protein expression. Furthermore, renal injury in preeclampsia associated with an elevated urinary podocin + EVs-to-nephrin + EVs ratio and may be mediated by prolonged exposure to cellfree HbF.