Effects of raloxifene therapy on plasma renin and aldosterone levels and blood pressure in postmenopausal women

Effects of anti-osteoporosis therapy on plasma aldosterone and renin

OBJECTIVE

This study aimed to investigate the effect of anti-osteoporosis therapy on plasma aldosterone concentration (PAC), plasma renin concentration (PRC) and the aldosterone/renin ratio (ARR) in patients with postmenopausal osteoporosis.

METHODS

In 60 patients with postmenopausal osteoporosis, bone mineral density (BMD), PAC and PRC were measured before and after treatment with alendronate (70 mg/week, n=22) or recombinant human parathyroid hormone (20 μg/day, n=35) for 48 weeks.

RESULTS

PAC was negatively correlated with the T-score of lumbar spine BMD and femoral neck BMD (lumbar r=-0.386, p<0.01; femoral neck r=-0.262, p<0.05). With the improvement in lumbar BMD after anti-osteoporosis treatment (T-score -3.4±0.5 vs. -3.1 ±0.4, p<0.0001), PAC decreased from 182.8±53.2 to 143.7±68.6 pg/mL (p<0.0001), PRC increased from 7.8±11.6 to 39.2±50.0 μIU/mL (p<0.0001) and the ARR decreased from 74.8±75.2 to 13.1±17.1 pg/μIU (p<0.0001). At baseline, 58% (35/60) of the patients had an ARR >37 pg/μIU, and the proportion decreased to 8% (5/57) after treatment.

CONCLUSION

Treatment with alendronate or parathyroid hormone causes decreased PAC and increased PRC, resulting in a decreased ARR in postmenopausal women with osteoporosis.

Repurposing existing drugs for COVID-19: an endocrinology perspective

BACKGROUND

Coronavirus Disease 2019 (COVID-19) is a multi-systemic infection caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), that has become a pandemic. Although its prevailing symptoms include anosmia, ageusia, dry couch, fever, shortness of brief, arthralgia, myalgia, and fatigue, regional and methodological assessments vary, leading to heterogeneous clinical descriptions of COVID-19. Aging, uncontrolled diabetes, hypertension, obesity, and exposure to androgens have been correlated with worse prognosis in COVID-19. Abnormalities in the renin-angiotensin-aldosterone system (RAAS), angiotensin-converting enzyme-2 (ACE2) and the androgen-driven transmembrane serine protease 2 (TMPRSS2) have been elicited as key modulators of SARS-CoV-2.

MAIN TEXT

While safe and effective therapies for COVID-19 lack, the current moment of pandemic urges for therapeutic options. Existing drugs should be preferred over novel ones for clinical testing due to four inherent characteristics: 1. Well-established long-term safety profile, known risks and contraindications; 2. More accurate predictions of clinical effects; 3. Familiarity of clinical management; and 4. Affordable costs for public health systems. In the context of the key modulators of SARS-CoV-2 infectivity, endocrine targets have become central as candidates for COVID-19. The only endocrine or endocrine-related drug class with already existing emerging evidence for COVID-19 is the glucocorticoids, particularly for the use of dexamethasone for severely affected patients. Other drugs that are more likely to present clinical effects despite the lack of specific evidence for COVID-19 include anti-androgens (spironolactone, eplerenone, finasteride and dutasteride), statins, N-acetyl cysteine (NAC), ACE inhibitors (ACEi), angiotensin receptor blockers (ARB), and direct TMPRSS-2 inhibitors (nafamostat and camostat). Several other candidates show less consistent plausibility. In common, except for dexamethasone, all candidates have no evidence for COVID-19, and clinical trials are needed.

CONCLUSION

While dexamethasone may reduce mortality in severely ill patients with COVID-19, in the absence of evidence of any specific drug for mild-to-moderate COVID-19, researchers should consider testing existing drugs due to their favorable safety, familiarity, and cost profile. However, except for dexamethasone in severe COVID-19, drug treatments for COVID-19 patients must be restricted to clinical research studies until efficacy has been extensively proven, with favorable outcomes in terms of reduction in hospitalization, mechanical ventilation, and death.

The G protein-coupled estrogen receptor GPER/GPR30 as a regulator of cardiovascular function

Endogenous estrogens are important regulators of cardiovascular homeostasis in premenopausal women and delay the development of hypertension and coronary artery disease. These hormones act via three different estrogen receptors affecting both gene transcription and rapid signaling pathways in a complex interplay. In addition to the classical estrogen receptors ERα and ERβ, which are known mediators of estrogen-dependent vascular effects, a G protein-coupled estrogen receptor termed GPER that is expressed in the cardiovascular system has recently been identified. Endogenous human 17β-estradiol, selective estrogen receptor modulators (SERMs) including tamoxifen and raloxifene, and selective estrogen receptor downregulators (SERDs) such as ICI 182,780 are all agonists of GPER, which has been implicated in the regulation of vasomotor tone and protection from myocardial ischemia/reperfusion injury. As a result, understanding the individual role of ERα, ERβ, and GPER in cardiovascular function has become increasingly complex. With accumulating evidence that GPER is responsible for a variety of beneficial cardiovascular effects of estrogens, this receptor may represent a novel target to develop effective strategies for the treatment of cardiovascular diseases by tissue-specific, selective activation of estrogen-dependent molecular pathways devoid of side effects seen with conventional hormone therapy.

Blood pressure effects of the oral contraceptive and postmenopausal hormone therapies

Oral contraceptives and postmenopausal hormone therapy may induce hypertension through multiple mechanisms, including sodium and volume retention. Numerous studies have shown significant increases in blood pressure (BP) with the chronic administration of oral contraceptives as well as reversibility with discontinuation. The effects of different classes of oral contraceptive agents and hormonal replacement therapy on BP and associated effects on other cardiovascular risk factors are covered in this article. Novel hormonal replacement therapy that lowers BP is also discussed.

Effects of raloxifene on the renin-angiotensin-aldosterone system and blood pressure in hypertensive and normotensive osteoporotic postmenopausal women

AIM

An increase in blood pressure after menopause has been documented. The renin-angiotensin-aldosterone system (RAAS) plays a central role in the regulation of blood pressure and in the pathophysiology of hypertension. This study investigated the effects of raloxifene, a selective estrogen receptor modulator, on components of the RAAS and blood pressure in hypertensive and normotensive osteoporotic postmenopausal women.

METHODS

A total of 41 hypertensive or normotensive postmenopausal women with osteoporosis or osteopenia were divided into four groups. Eleven hypertensive and eight normotensive women received raloxifene hydrochloride (60 mg/day) p.o. for 6 months, and 12 hypertensive and 10 normotensive women did not receive raloxifene hydrochloride for 6 months. In all of the hypertensive women, blood pressure had been controlled prior to the start of the study using a variety of antihypertensive drugs other than angiotensin-converting enzyme (ACE) inhibitors, angiotensin (Ang)II type 1 receptor antagonists or diuretics. Plasma renin activity (PRA), serum ACE activity, plasma AngI, AngII and aldosterone concentrations, and blood pressure were measured before and 6 months after the start of the study.

RESULTS

No significant changes in PRA, ACE activity, or the AngI, AngII or aldosterone levels were observed in any of the groups. In all the groups, blood pressure remained unchanged.

CONCLUSION

Raloxifene may have no significant effect on the RAAS or blood pressure in hypertensive and normotensive osteoporotic postmenopausal women.

Morphologic effects of epithelial ion channels on the mouse uterus: differences between raloxifene analog (LY117018) and estradiol treatments

OBJECTIVE

Estrogen regulates the expression of epithelial Na(+) channel (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR). Our purpose was to assess the effects of raloxifene analog LY117018 on the expression of ENaC and CFTR in ovariectomized mice.

STUDY DESIGN

Three groups of 5 female ovariectomized mice were treated with 17beta-estradiol benzoate (E2), LY117018 (LY), or vehicle, respectively, for 4-12 weeks. Effects on the messenger ribonucleic acid expression levels of ENaC and CFTR channels in the uterus were studied using real-time reverse transcriptase-polymerase chain reaction.

RESULTS

E2 treatment induced CFTR expression, repressed ENaC expression and resulted in fluid accumulation in the uterus. In contrast, LY induced CFTR expression, did not repress ENaC expression, and caused no fluid accumulation.

CONCLUSION

Estradiol and LY117018 differentially regulate the expression of CFTR and ENaC in ovariectomized mouse uterus. This finding suggests that uterine fluid accumulation can be controlled mainly by targeting the ENaC.

The effects of raloxifene hydrochloride on ocular hemodynamics and visual function

OBJECTIVE

To assess the comprehensive effects of raloxifene hydrochloride on retinal, choroidal and retrobulbar hemodynamics and on visual function in post-menopausal women.

DESIGN

Twenty-four post-menopausal women (age 55 +/- 3.8 years) were recruited for this cross-sectional study: 12 received placebo and 12 received raloxifene hydrochloride 60 mg once a day for 3 months. Baseline measurements of both groups included heart rate (HR), blood pressure (BP), visual acuity, contrast sensitivity and intraocular pressure (IOP) for both eyes. A comprehensive ocular blood flow (OBF) assessment was obtained for each patient in a randomly chosen study eye. Retinal blood flow data was obtained using confocal scanning laser Doppler flowmetry [Heidelberg Retinal Flowmeter (HRF)]. Color Doppler imaging (CDI) was used to assess retrobulbar hemodynamics in the ophthalmic, central retinal, short nasal and temporal posterior ciliary arteries. Baseline vision and hemodynamics in post-menopausal subjects were compared using paired Student's t tests, and the percentage change in baseline versus 3-month parameters was analyzed.

RESULTS

There were no statistically significant differences between 3 months of raloxifene therapy and placebo in terms of age, HR, arterial or mean BP, visual acuity, contrast sensitivity, IOP or retinal or retrobulbar blood flow.

CONCLUSION

Raloxifene therapy at 60 mg/day had no clinically significant impact on BP, IOP or OBF in post-menopausal women.