Cortisol response and ovarian hormones in juvenile and cycling female Cebus monkeys: effect of stress and dexamethasone

The association between chronic psychological stress and uterine fibroids risk: A meta-analysis of observational studies

The association between chronic psychological stress and uterine fibroids (UFs) risk remains unclear. In this study, a meta-analysis of observational studies was performed to explore the reported association between them. A literature search was performed in PubMed, EMBASE, and Web of Science to identify relevant published articles. A random-effect model was used to examine pooled odds ratio (OR) and 95% confidence interval (CI). Additionally, subgroup analyses and two-stage random-effect dose-response meta-analysis were performed. A total of six articles with seven studies were included in this meta-analysis. For the highest versus lowest category of chronic psychological stress, the pooled OR was 1.24 (95% CI [1.15, 1.34]; p = .000). Through subgroup analyses, we found a positive association between chronic psychological stress and UFs risk especially in non-Hispanic Blacks studies (OR, 1.24, 95% CI [1.14, 1.34], p = .000). When evaluating for a dose-response, we found a weak correlation between chronic psychological stress and UFs risk, especially for the severe (OR, 1.17, 95% CI [1.07, 1.29]) and very severe (OR, 1.23, 95% CI [1.07, 1.41]) categories. Our meta-analysis shows a statistically significant association between chronic psychological stress and UFs risk particularly for non-Hispanic Blacks. Interventions aiming to reduce chronic psychological stress may be useful to decrease the prevalence of UFs.

Rightward Tympanic Membrane Temperature Bias During Acute Restraint-Isolation Stress in Marmoset Monkeys

Restraint is widely used to experimentally assess stress-induced effects. Surprisingly, little is known on how marmosets - an increasingly used small primate - process and respond to restraint stress. Here, we assessed blood cortisol concentration and tympanic membrane temperatures (TMT) in adult marmoset monkeys (Callithrix penicillata) during 0, 15, or 30 min of restraint and social isolation in a small cage. TMT reflects blood flow to the cerebral hemispheres, which in turn reflects neural activity. Baseline TMT were subtracted from post-test measures to establish shifts in blood flow possibly induced by ipsilateral brain activity. Cortisol was assayed immediately after the post-test assessment of the TMT. Marmosets restrained-isolated for 15 or 30 min had higher cortisol levels than the non-restrained-isolated group. Furthermore, significant changes in TMT were detected only in the right ear of the restrained-isolated groups, this effect being unrelated to overall body temperature or the time needed to capture/measure the TMT. Adult marmosets thus readily perceive a significant reduction in their range of movement as an event of sufficient negative intensity and/or duration to activate a pertinent neuroendocrine response. Also, an asymmetrical shift in their TMT reflects that such an aversive event may be rightwardly biased in this primate.

Factors influencing alopecia and hair cortisol in rhesus macaques (Macaca mulatta)

BACKGROUND

Alopecia can occur in captive non-human primates, but its etiology is poorly understood. The purpose of this study was to assess alopecia and hair cortisol in rhesus monkeys and to identify the potential risk factors.

METHODS

Subjects were 117 rhesus monkeys at two National Primate Research Centers. Photographs and hair samples were obtained during routine physicals. Photographs were analyzed using Image J software to calculate hair loss, and hair samples were assayed for cortisol.

RESULTS

Age, days singly housed, and their interactions contributed to the alopecia model for both facilities. Sex and location changes contributed to the hair cortisol model for Facility 1; sedations contributed for Facility 2. Alopecia and hair cortisol were associated at Facility 1.

CONCLUSIONS

Captive management practices can affect alopecia and hair cortisol. However, there are facility differences in the relationship between alopecia and hair cortisol and in the effect of intrinsic variables and management procedures.

Lifetime abuse victimization and risk of uterine leiomyomata in black women

OBJECTIVE

Uterine leiomyomata (UL) are a major contributor to gynecologic morbidity and medical costs, and black women are disproportionately affected by the condition. Previous studies have linked UL to psychosocial stress, including child abuse. We assessed the association between lifetime abuse victimization and UL among 9910 premenopausal women.

STUDY DESIGN

Data were derived from the Black Women's Health Study, a prospective cohort study. In 2005, participants reported their experiences of physical and sexual abuse within each life stage (childhood, adolescence, adulthood). Biennial follow-up questionnaires from 2005 through 2011 ascertained new UL diagnoses. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated using Cox regression.

RESULTS

There were 1506 incident UL cases diagnosed by ultrasound or surgery. UL incidence was higher among women who reported child abuse, particularly sexual abuse. Relative to no abuse across the life span, RRs were 1.16 (95% CI, 1.02-1.33) for physical abuse only, 1.34 (95% CI, 1.09-1.66) for sexual abuse only, and 1.17 (95% CI, 0.99-1.39) for both physical and sexual abuse in childhood. RRs for 1-3 and 4 or more incidents of child sexual abuse were 1.29 (95% CI, 1.04-1.61) and 1.41 (95% CI, 1.07-1.85), respectively, whereas the RRs for low, intermediate, and high frequencies of child physical abuse were 1.19, 1.04, and 1.23, respectively. The association was strongest for the highest category of child abuse severity (RR, 1.57; 95% CI, 1.19-2.07). No associations were found for teen or adult abuse.

CONCLUSION

In the present study, child sexual abuse was an independent risk factor for UL, supporting the hypothesis that childhood adversity increases UL risk.

Suppression of ovulation by a synthetic progestin in the capuchin monkey

BACKGROUND

From the limited research in New World monkeys it is not clear whether they are as sensitive to the antiovulatory effects of synthetic progestins as noted in human beings. We examined whether levonorgestrel prevented ovulation in the capuchin monkey.

METHODS

Cebus apella monkeys were treated orally with two doses of 2 mg of levonorgestrel, 8-9 hours apart, in four periovulatory stages assessed by laparoscopy.

RESULTS

Levonorgestrel-induced luteinization of the follicle prevented oocyte release up to 8 hours before ovulation. Unhealthy oocytes were recovered from 46% of unruptured follicles. Luteal progesterone was reduced by 55%, 35%, and 25% according to when levonorgestrel was given -2, -1, and 0 day from estradiol peak respectively.

CONCLUSION

The capuchin monkey, a neotropical primate in which progesterone circulates at levels much higher than in Old World primates and human beings, is sensitive to the antiovulatory effects of synthetic progestins.

Perceived racial discrimination and risk of uterine leiomyomata

BACKGROUND

The incidence of uterine leiomyomata (fibroids, myomas) is 2-3 times higher in black women than white women. Black women also report higher levels of racial discrimination. We evaluated the hypothesis that greater exposure to racism increases myoma risk in black women.

METHODS

Data were derived from the Black Women's Health Study, a prospective cohort study of US black women age 21-69 years in 1995. In 1997, women reported on "everyday" and "lifetime" experiences of racism. From 1997 through 2003, we followed 22,002 premenopausal women to assess the association between self-reported racism and risk of myomas. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were estimated from Cox regression models.

RESULTS

During 107,127 person-years of follow-up, 3440 new cases of uterine myomas confirmed by ultrasound (n = 2774) or surgery (n = 666) were reported. All IRRs for "lifetime" and "everyday" experiences of racism were above 1.0. Using a summary variable that averaged the responses from 5 "everyday" racism items, multivariable IRRs comparing quartiles 2, 3, and 4 to quintile 1 (lowest) were 1.16 (95% CI = 1.04-1.29), 1.19 (1.06-1.32), and 1.27 (1.14-1.43), respectively. Multivariable IRRs comparing women who reported 1, 2, or 3 lifetime occurrences of major discrimination (ie, job, housing, or police) relative to those who reported none were 1.04 (0.96-1.13), 1.17 (1.07-1.28), and 1.24 (1.10-1.39), respectively. Results did not vary according to case definition (ultrasound vs. surgery) or health care utilization. Associations were weaker among foreign-born women and among women with higher coping skills.

CONCLUSIONS

Perceived racism was associated with an increased risk of uterine myomas in US-born black women.

Circadian cortisol secretion and circadian adrenal responses to ACTH are maintained in dexamethasone suppressed capuchin monkeys (Cebus apella)

We tested the hypothesis that the capuchin monkey adrenal (Cebus apella) gland has oscillatory properties that are independent of adrenocorticotropic hormone (ACTH) by exploring under ACTH suppression by dexamethasone: (i) maintenance of a circadian rhythm of plasma cortisol and (ii) clock time dependency of plasma cortisol response to exogenous ACTH. The capuchin monkey had a clear ACTH and plasma cortisol rhythm. Dexamethasone treatment resulted in low non-rhythmic ACTH levels and decreased cortisol to 1/10 of control values; nevertheless, the circadian rhythm of plasma cortisol persisted. We found that cortisol response to exogenous ACTH was clock time-dependent. The maximal response to ACTH occurred at the acrophase of the cortisol rhythm (0800 h). These results suggest that the capuchin monkey adrenal cortex may possess intrinsic oscillatory properties that participate in the circadian rhythm of adrenal cortisol secretion and in the circadian cortisol response to ACTH.