Gonadotropin-releasing hormone agonist in premenopausal women does not alter hypothalamic-pituitary-adrenal axis response to corticotropin-releasing hormone

Effects of Sleep Fragmentation and Estradiol Decline on Cortisol in a Human Experimental Model of Menopause

CONTEXT

Perturbations to the hypothalamic-pituitary-adrenal (HPA) axis have been hypothesized to increase postmenopausal cardiometabolic risk. Although sleep disturbance, a known risk factor for cardiometabolic disease, is prevalent during the menopause transition, it is unknown whether menopause-related sleep disturbance and estradiol decline disturb the HPA axis.

OBJECTIVE

We examined the effect of experimental fragmentation of sleep and suppression of estradiol as a model of menopause on cortisol levels in healthy young women.

METHODS

Twenty-two women completed a 5-night inpatient study during the mid-to-late follicular phase (estrogenized). A subset (n = 14) repeated the protocol after gonadotropin-releasing hormone agonist-induced estradiol suppression. Each inpatient study included 2 unfragmented sleep nights followed by 3 experimental sleep fragmentation nights. This study took place with premenopausal women at an academic medical center. Interventions included sleep fragmentation and pharmacological hypoestrogenism, and main outcome measures were serum bedtime cortisol levels and cortisol awakening response (CAR).

RESULTS

Bedtime cortisol increased 27% (P = .03) and CAR decreased 57% (P = .01) following sleep fragmentation compared to unfragmented sleep. Polysomnographic-derived wake after sleep-onset (WASO) was positively associated with bedtime cortisol levels (P = .047) and negatively associated with CAR (P < .01). Bedtime cortisol levels were 22% lower in the hypoestrogenized state compared to the estrogenized state (P = .02), while CAR was similar in both estradiol conditions (P = .38).

CONCLUSION

Estradiol suppression and modifiable menopause-related sleep fragmentation both independently perturb HPA axis activity. Sleep fragmentation, commonly seen in menopausal women, may disrupt the HPA axis, which in turn may lead to adverse health effects as women age.

Corticotropin releasing hormone promotes inflammatory bowel disease via inducing intestinal macrophage autophagy

Psychosocial stress is a vital factor contributing to the pathogenesis and progression of inflammatory bowel disease (IBD). The contribution of intestinal macrophage autophagy to the onset and development of IBD has been widely studied. Herein, we investigated the underlying mechanism of psychosocial stress in an IBD mouse model pertaining to macrophage autophagy. Corticotropin releasing hormone (CRH) was peripherally administrated to induce psychosocial stress. For in vivo studies, dextran sulfate sodium (DSS) was used for the creation of our IBD mouse model. For in vitro studies, lipopolysaccharide (LPS) was applied on murine bone marrow-derived macrophages (BMDMs) as a cellular IBD-related challenge. Chloroquine was applied to inhibit autophagy. We found that CRH aggravated the severity of DSS-induced IBD, increasing overall and local inflammatory reactions and infiltration. The levels of autophagy in intestinal macrophages and murine BMDMs were increased under these IBD-related inflammatory challenges and CRH further enhanced these effects. Subsequent administration of chloroquine markedly attenuated the detrimental effects of CRH on IBD severity and inflammatory reactions via inhibition of autophagy. These findings illustrate the effects of peripheral administration of CRH on DSS-induced IBD via the enhancement of intestinal macrophage autophagy, thus providing a novel understanding as well as therapeutic target for the treatment of IBD.

Decline in endothelial function across the menopause transition in healthy women is related to decreased estradiol and increased oxidative stress

Endothelial function declines progressively across stages of the menopause transition; however, the mechanisms contributing to this decline are unknown. We hypothesized that differences in endothelial function among pre-, peri, and postmenopausal women are related to differences in estradiol and oxidative stress. Brachial artery flow-mediated dilation (FMD) was measured in 87 healthy women categorized by menopause stage (24 premenopausal, 17 early and 21 late perimenopausal, and 25 postmenopausal) before and after 3 days of ovarian hormone suppression (gonadotropin releasing hormone antagonist [GnRHant]) alone, and an additional 3 days of GnRHant with concurrent transdermal estradiol or placebo add-back treatment. In 82 women, FMD during acute vitamin C (antioxidant) infusion was measured before and after GnRHant + add-back. Before GnRHant, FMD was different among groups (p < 0.005; reduced across stages of menopause). Vitamin C increased FMD in late peri- and post- (p < 0.005) but not pre- or early perimenopausal women (p > 0.54). After GnRHant alone, FMD decreased in pre- and peri- (p < 0.01), but not postmenopausal women, and was restored to premenopausal levels by estradiol add-back in the pre- and perimenopausal groups. Vitamin C improved FMD in pre-, peri-, and postmenopausal women on GnRHant + placebo. There was no effect of vitamin C on FMD in women on GnRHant + estradiol. These observations support the concept that the decline in endothelial function across the menopause transition is related to the loss of ovarian estradiol. The decline in estradiol may alter redox balance, thereby increasing oxidative stress and impairing endothelial function.

Intestinal autophagy links psychosocial stress with gut microbiota to promote inflammatory bowel disease

Psychosocial stress is a critical inducing factor of inflammatory bowel diseases (IBD), while autophagy is a novel central issue of IBD development. The present study investigated the potential role of autophagy in stress-related IBD in patients and animal model. The correlation between psychosocial stress and intestinal autophagy was determined in 23 patients with IBD. Corticotropin-releasing hormone (CRH), a well-established inducer of psychosocial stress, was administrated in dextran sulfate sodium (DSS)-induced IBD mice and lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMDM). In IBD patients, the autophagy markers beclin-1, LC3-II/I ratio, Atg16L1, and Atg4B were significantly enhanced. The psychosocial stress score was positively associated with the levels of beclin-1 and the LC3II/I ratio in intestinal biopsy specimens. In IBD mouse model, CRH significantly aggravated intestinal inflammation, increased Paneth cell metaplasia, and enhanced intestinal autophagy (beclin-1, Atg16L1, PIK3R4, and Atg4B upregulation; GAA, CTSD, and PPKAA1 downregulation). Additionally, the CRH-induced gut microbial dysbiosis was evidenced by a marked increase in the number of detrimental bacteria. In LPS-stimulated BMDM, CRH substantially increased M1/M2 polarization and thus promoted inflammation. In both IBD mice and LPS-treated BMDM, blockade of autophagy by chloroquine abrogated the unbeneficial effects of CRH, whereas autophagy inducer rapamycin resulted in a pronounced protective effect against IBD lesion. Our data demonstrate that psychosocial stress may link the enhanced intestinal autophagy by modulating gut microbiota and inflammation to aggravate IBD. These data indicate autophagy as a promising therapeutic target for psychosocial stress-related IBD.