In vivo and in vitro estrogenic and progestagenic actions of Tibolone

Relationship between menopausal hormone therapy and colorectal cancer: a cohort study utilizing the health insurance database in South Korea (HISK)-II

OBJECTIVE

Many studies have demonstrated that menopausal hormone therapy is associated with a reduced risk for colorectal cancer. This study investigated the relationship between specific hormone therapy regimens and colorectal cancer risk in postmenopausal women in South Korea using national insurance claims data.

METHODS

This population-based, retrospective cohort study used insurance data provided by the Health Insurance Review and Assessment Service between 2007 and 2020. The hormone therapy group comprised women ≥40 years of age who underwent hormone therapy for the first time between 2011 and 2014. The control group included women ≥40 years of age who visited medical institutions for menopause-related issues during the same period but did not undergo hormone therapy.

RESULTS

After 1:1 propensity score matching, 153,736 women were grouped into either the hormone therapy or nonhormone therapy groups. The incidence of colorectal cancer was 46 and 53 per 100,000 person-years in the nonhormone therapy and hormone therapy groups, respectively. Hormone therapy was associated with an increased risk for colorectal cancer (hazard ratio 1.124 [95% confidence interval 1.002-1.261]). Subgroup analysis, according to hormone therapy type, revealed no significant differences in the risk of colorectal cancer for estrogen plus progestogen or estrogen therapy alone; however, tibolone was associated with an increased risk of colorectal cancer compared to nonhormone therapy (hazard ratio, 1.178 [95% confidence interval, 1.021-1.359]).

CONCLUSIONS

This study found an increased risk of colorectal cancer in women receiving hormone therapy, and tibolone was significantly associated with an increased risk of colorectal cancer. However, the magnitude of the increase was small and unlikely to be of clinical significance.

Tibolone as Hormonal Therapy and Neuroprotective Agent

Tibolone (TIB), a selective tissue estrogenic activity regulator (STEAR) in clinical use by postmenopausal women, activates hormonal receptors in a tissue-specific manner. Estrogenic activity is present mostly in the brain, vagina, and bone, while the inactive forms predominate in the endometrium and breast. Conflicting literature on TIB's actions has been observed. While it has benefits for vasomotor symptoms, bone demineralization, and sexual health, a higher relative risk of hormone-sensitive cancer has been reported. In the brain, TIB can improve mood and cognition, neuroinflammation, and reactive gliosis. This review aims to discuss the systemic effects of TIB on peri- and post-menopausal women and its role in the brain. We suggest that TIB is a hormonal therapy with promising neuroprotective properties.

Dynamic Regulation of JAK-STAT Signaling Through the Prolactin Receptor Predicted by Computational Modeling

Introduction

The expansion of insulin-producing beta cells during pregnancy is critical to maintain glucose homeostasis in the face of increasing insulin resistance. Prolactin receptor (PRLR) signaling is one of the primary mediators of beta cell expansion during pregnancy, and loss of PRLR signaling results in reduced beta cell mass and gestational diabetes. Harnessing the proliferative potential of prolactin signaling to expand beta cell mass outside of the context of pregnancy requires quantitative understanding of the signaling at the molecular level.

Methods

A mechanistic computational model was constructed to describe prolactin-mediated JAK-STAT signaling in pancreatic beta cells. The effect of different regulatory modules was explored through ensemble modeling. A Bayesian approach for likelihood estimation was used to fit the model to experimental data from the literature.

Results

Including receptor upregulation, with either inhibition by SOCS proteins, receptor internalization, or both, allowed the model to match experimental results for INS-1 cells treated with prolactin. The model predicts that faster dimerization and nuclear import rates of STAT5B compared to STAT5A can explain the higher STAT5B nuclear translocation. The model was used to predict the dose response of STAT5B translocation in rat primary beta cells treated with prolactin and reveal possible strategies to modulate STAT5 signaling.

Conclusions

JAK-STAT signaling must be tightly controlled to obtain the biphasic response in STAT5 activation seen experimentally. Receptor up-regulation, combined with SOCS inhibition, receptor internalization, or both is required to match experimental data. Modulating reactions upstream in the signaling can enhance STAT5 activation to increase beta cell survival.

Electronic supplementary material

The online version of this article (10.1007/s12195-020-00647-8) contains supplementary material, which is available to authorized users.

Recent advances on the action of estrogens and progestogens in normal and pathological human endometrium

Hormonal control in the development of the normal endometrium is of the utmost importance. It is well established that the two main hormones involved in this process are estradiol and progesterone, which are also implicated in the pathological conditions concerning endometriosis and endometrial carcinoma. There are two types of endometrial carcinoma: type I which represents 80%–90% is hormone-dependent, whereas the remainder is type II and is hormone-independent. The endometrial tissue contains all the enzymatic systems in the formation and transformation of the various hormones, including aromatases, sulfatases, sulfotransferases, hydroxysteroid dehydrogenases, hydroxylases, and glucuronidases. It is interesting to note that increased sulfatase activity is correlated with severity of endometriosis. An increased sulfatase/sulfotransferase ratio represents a poor prognosis in patients with endometrial carcinoma. Treatment with hormone replacement therapy (estrogens+progestogens), as well as with tibolone, is most effective in protecting this tissue by climacteric alterations, owing to the significant decrease of ovarian hormones. In conclusion, enzymatic control can open appealing perspectives to protect this organ from possible pathological alterations.

Tibolone in postmenopausal women with systemic lupus erythematosus: a pilot study

OBJECTIVE

To determine the influence of the use of tibolone on the frequency of flares of systemic lupus erythematosus (SLE) in postmenopausal patients.

METHODS

Thirty patients with inactive or controlled SLE were included in the study. Patients were randomized to receive a 12-month course of either tibolona (2.5 mg/day) or placebo. The following were investigated: hypoestrogenism symptoms by Kupperman index, weight; anti-dsDNA antibodies; SLE flares (frequency) assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI); and biochemical profile (total cholesterol, high-density lipoprotein cholesterol [HDL-C], triglycerides, complement components [C3/C4], alpha1-acid glycoprotein, urea, creatinine, 24-h proteinuria, C-reactive protein and erythrocyte sedimentation rate).

RESULTS

The reduction in Kupperman index was greater in the patients using tibolone than in those using placebo. The mean SLEDAI was not different between the groups during the study as well as SLE flare frequency (tibolone: 2/15 [13.3%] vs. placebo: 1/15 [6.7%]; p=0.54). All cases of flares were considered mild to moderate. Although the groups were similar at the baseline evaluation, after 6 and 12 months of treatment lower values were found in the tibolone group for triglycerides (6 months: 161.6+/-30.9 mg/dl vs. 194.4+/-46.5; p=0.04; 12 months 163.7+/-29.8 mg/dl vs. 204.1+/-49.9 mg/dl; p=0.02; tibolone vs. placebo group, respectively) and for HDL-C (6 months: 40.7+/-10.7 mg/dl vs. 53.4+/-16.5; p=0.02; 12 months: 47.2+/-7.9 mg/dl vs. 63.2+/-16.3mg/dl; p<0.01; tibolone vs. placebo group, respectively). There were no differences between the two groups in any of the remaining variables.

CONCLUSION

In patients with inactive or stable SLE, the short-term use of tibolone did not significantly affect the frequency of flares. In addition, tibolone was well tolerated and effective to control hypoestrogenism related symptoms in SLE patients.