Medroxyprogesterone acetate prevents the cardioprotective and anti-inflammatory effects of 17β-estradiol in an in vivo model of myocardial ischemia and reperfusion

17β-Estradiol attenuates inflammation and tendon degeneration in a rat model of Achilles tendinitis

INTRODUCTION

17β-Estradiol (E2) is an immune-regulatory agent with anti-inflammatory effects. However, it is still unknown whether E2 exerts pharmacological properties against Achilles tendinitis (AT). This study aims to investigate the effects of E2 on AT and its underlying mechanisms.

MATERIALS AND METHODS

The established model of Achilles tendinitis was intraperitoneally injected with E2 (10, 20, or 30 μg/kg/d). After 8 weeks, biomechanical properties of the Achilles tendon were determined. Hydroxyproline content and tendon degeneration-related biomarkers were determined. The levels of inflammatory cytokines and apoptotic-related biomarkers in tendon tissues were determined. Furthermore, western blotting was determined to detect the expressions of ER-α and the PI3K/Akt pathway in tendon tissues.

RESULTS

E2 relieved AT-related symptoms in a dose-dependent manner. E2 ameliorated tendon degeneration by regulating tendon degeneration-related biomarkers (e.g., collagen type I and III, Decorin (DCN), and tenascin-C). Besides, treatment with E2 suppressed inflammatory cytokines and increased anti-inflammatory cytokines. Treatment with E2 also regulated cell apoptosis in tendon tissues. The underlying mechanism study revealed that treatment with E2 activated ER-α and upregulated the PI3K/Akt pathway.

CONCLUSION

The regulatory effects of E2 on inflammation and tendon degeneration in a rat model of AT were associated with the ER-α and the PI3K/Akt signaling pathways.

Cardioprotective Role of Estrogen in Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy (TC) is a rare, reversible cause of left ventricular wall motion abnormality (LVWMA) that mimics the presentation of acute myocardial infarction (AMI). TC is usually preceded by an emotional or physical stressor and appears to be more common in postmenopausal women. Various pathophysiological hypotheses of TC have been proposed, but the exact mechanism of action remains elusive. Elevated levels of catecholamines leading to cardiac dysfunction are the most prevalent hypothesis. The protective role of estrogen in the development of cardiomyopathies has been studied extensively. International Takotsubo Diagnostic Criteria (InterTAK) and Mayo clinic diagnostic criteria both have the stipulation stating prevalence of TC is higher in postmenopausal women which hints towards the protective role of estrogen in the development of TC. To review the protective role of estrogen in the mechanism of this novel pathology, we searched Pubmed and Google scholar for the relevant articles by using keywords such as: “takotsubo cardiomyopathy”, “apical ballooning”, “broken heart syndrome”, “stress cardiomyopathy”, “left ventricle wall motion abnormality”, “estrogen”, “estradiol” and “sex hormones”. Our research revealed that although the prevalence of TC is greater in postmenopausal women as compared to men, the prognosis is worse in men. It also revealed the involvement of multiple cellular pathways under the influence of estrogen that could explain the cardioprotective effect of estrogen. Most of the articles found were based on animal studies, thus, there is an emphasis on future human studies. However, we strongly suggest evaluating estrogen levels as part of the initial workup for any patient presenting with signs and symptoms of cardiac pathology.

Effect of Sorbus domestica and its active constituents in an experimental model of colitis rats induced by acetic acid

ETHNOPHARMACOLOGICAL RELEVANCE

In Turkish folk medicine, leaves of Sorbus domestica are used for the treatment of burns, cough, stomachache, bradyuria, kidney stone. The fruits of this plant are used for diarrhoea.

AIM OF THE STUDY

This study was carried out to investigate the effect of S. domestica on ulcerative colitis induced by acetic acid in rats.

MATERIALS AND METHODS

The crude methanolic extract of fruits was sequentially fractionated into five subextracts; dichloromethane, diethyl ether, ethyl acetate, n-butanol and aqueous extracts. Effects of the extract, subextracts and fractions were investigated in acetic acid-induced rat colitis model. The colonic interleukin-6 (IL-6), tumor necrosis factor (TNF-α), nitrite, superoxide dismutase (SOD), glutathione (GSH), lipid peroxidation (LPO), catalase (CAT), and malondialdehyde (MDA) levels as well as the caspase-3 and myeloperoxidase (MPO) activities were measured to determine the activity. Histopathological analyzes were also performed on the colon tissue of rats.

RESULTS

The methanolic extract and diethylether subextract have led to a noteworthy decrease in MPO, caspase-3, IL-6, TNF-α, MDA, and nitrite levels in the colon tissue and blood. In addition, histopathological analysis results were supported by biochemical parameters. After confirmation of the activity against ulcerative colitis, the diethyl ether subextract was subjected to more chromatographic separation for the isolation of compounds 1, 2 and 3. The structures of these three compounds were elucidated as vanillic acid 4-O-α-L-rhamnopyranoside (1), protocateuic acid anhydrite (2) and trivanilloyl-(1,3,4-trihydroxybenzol) ester (3).

CONCLUSION

In this study, the potential of S. domestica in the treatment of colitis was investigated. Fruits of this plant were found to have important anti-inflammatory and antioxidant activities. Through isolation techniques, vanillic acid 4-O-α-L-rhamnopyranoside, protocateuic acid anhydrite and trivanilloyl-(1,3,4-trihydroxybenzol) ester were determined as the main active components of the fruits. Consequently, S domestica might be a promising candidate for upcoming use the prevention and treatment of various disorders, such as inflammatory bowel diseases, irritable bowel syndrome and Clostridium difficile infection.

The impact of exercise modality and menstrual cycle phase on circulating cardiac troponin T

OBJECTIVES

It is unclear whether exercise modality (moderate-intensity continuous [MCE]; high-intensity interval [HIE]) and menstrual cycle phase (follicular [FP]; luteal [LP]), individually or in combination, mediate the commonly observed exercise-induced elevation in cardiac troponin T (cTnT). This study examines cTnT responses to MCE and HIE during both the FP and LP.

DESIGN

Randomised crossover study.

METHODS

Seventeen healthy, eumenorrheic women completed four trials including MCE (60% VO_2max steady-state cycling until 300kJ) and work-equivalent HIE (repeated 4-min cycling at 90% VO_2max interspersed with 3-min rest) during both the FP and LP. The FP and LP were verified based on ovarian hormones. Serum cTnT was assessed using a high-sensitivity assay before, immediately after, and 1 (1HR), 3 (3HR) and 4 (4HR) hours after exercise. cTnT values were corrected for plasma volume changes.

RESULTS

cTnT was significantly elevated (p<0.05) post-exercise in both MCE (at 3HR and 4HR) and HIE (at 1HR, 3HR and 4HR). No statistically significant difference (p>0.05) in peak post-exercise cTnT, which mostly occurred at 3HR, was seen among the four trials (median [range], ngl^-1: 5.2 [1.7-18.1] after MCE during FP; 4.8 [1.7-24.9] after MCE during LP, 8.2 [3.9-24.8] after HIE during FP and 6.9 [1.7-23.1] after HIE during LP).

CONCLUSIONS

A single 300kJ bout of both MCE or HIE resulted in a significant post-exercise increase in cTnT, with no differences in peak cTnT response between menstrual cycle phases or between exercise modes, but the cTnT elevation occurs slightly earlier after HIE.

Efficacy of Pyrus elaeagnifolia subsp. elaeagnifolia in acetic acid–induced colitis model

In Turkish folk medicine, the fruits of Pyrus elaeagnifolia subsp. elaeagnifolia have been used to treat diarrhea and detoxify poisonous snake bites by enlarging the wound. The aim of the study was to confirm the ethnopharmacological usage of the plant using in vivo and in vitro models. Experimental colitis was performed under anesthesia by intrarectal administration of acetic acid in rats, and the extracts were administered orally. The colonic malondialdehyde (MDA), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and nitrite levels, in addition to the myeloperoxidase (MPO) and caspase-3 activities, were measured to determine the effects of the plant extracts. The methanol (MeOH) extract revealed a significant decrease in MPO and caspase-3 levels. The MeOH extract was found to have the highest total tannin content. It was also found to have significant antioxidant (p ˂ 0.01) and anti-inflammatory activities (p ˂ 0.05) in acetic acid induced colitis rat model . According to our results, the present study exhibited a decrease in MDA, nitrite, IL-6, and TNF-α levels in the colon tissue and blood in the MeOH extract treated group. The findings of this study can help in treating various disorders, such as Clostridium difficile infection, irritable bowel syndrome, and inflammatory bowel diseases.

Does progesterone have protective effects on ovarian ischemia-reperfusion injury?

Objective:

The aim of the present study was to evaluate the effects of progesterone (PG) against ovarian ischemia-reperfusion (I/R) injury through the evaluation of biochemical and histopathologic parameters.

Material and Methods:

Twenty-one female Wistar albino rats were divided into three groups. Group 1: Sham; group 2: I/R; group 3: I/R+PG (8 mg/kg). PG was administered intraperitoneally to the rats in group 3, 30 minutes before a detorsion operation. Ovarian I/R injury was evaluated in serum and tissue by using biochemical parameters including malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index, neutrophil gelatinase-associated lipocalin (NGAL) and immunofluorescence staining by using a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.

Results:

Serum and tissue TOS levels were significantly lower in group 3 than in group 2. Tissue TAS levels were higher in group 3 than in group 2 (p<0.001). NGAL and MDA levels were similar between the groups. Histologic score, including vascular congestion, hemorrhage, polymorphonuclear neutrophils, and interstitial edema, was higher in group 2. Pre-treatment with PG decreased the score, but this difference was not statistically significant. The number of apoptotic cells was higher in group 2 than in groups 1 and 3. The TUNEL-positive cell number decreased with PG in group 3.

Conclusion:

Preoperative PG treatment might exert protective effects on ovarian I/R injury through its anti-apoptotic and antioxidative properties.

The effect of progesterone in the prevention of the chemically induced experimental colitis in rats

PURPOSE

To study the effects of progesterone on an experimental colitis model.

METHODS

Wistar albino rats were treated subcutaneously with 2mg/kg once a day during seven days Colitis was induced by intrarectal administration of 5mg trinitrobenzene sulfonic acid (TNBS). Disease activities, macroscopic and microscopic scores were evaluated. To determine the response provoked by progesterone we measured Colonic malondialdehyde (MDA), TNF alfa, IL-6 and Nitric oxide (NO) levels in addition to the MPO (Myeloperoxidase) and caspase-3 activities.

RESULTS

Progesterone ameliorated significantly the macroscopic and microscopic scores. TNBS-induced colitis significantly increased the colonic MDA levels and caspase-3 activities in group 2 in comparison to the control group. The results of the study revealed a decline in MDA, NO, IL6 and TNF-α levels in the colon tissue and in blood due to progesterone therapy in group 3 when compared to the group 2, a significant improvement. Progesterone treatment was associated with decreased MDA, MPO, TNF alfa and caspase-3 activity.

CONCLUSION

Progesterone therapy decreased oxidative damage in the colonic mucosa.

Medroxyprogesterone acetate aggravates oxidative stress and left ventricular dysfunction in rats with chronic myocardial infarction

The role of estrogens during myocardial ischemia has been extensively studied. However, effects of a standard hormone replacement therapy including 17β-estradiol (E2) combined with medroxyprogesterone acetate (MPA) have not been assessed, and this combination could have contributed to the negative outcomes of the clinical studies on hormone replacement. We hypothesized that adding MPA to an E2 treatment would aggravate chronic heart failure after experimental myocardial infarction (MI). To address this issue, we evaluated clinical signs of heart failure as well as left ventricular (LV) dysfunction and remodeling in ovariectomized rats subjected to chronic MI receiving E2 or E2 plus MPA. After eight weeks MI E2 showed no effects. Adding MPA to E2 aggravated LV remodeling and dysfunction as judged by increased heart weight, elevated myocyte cross-sectional areas, increased elevated left ventricle end diastolic pressure, and decreased LV fractional shortening. Impaired LV function in rats receiving MPA plus E2 was associated with increased cardiac reactive oxygen species generation and myocardial expression levels of NADPH oxidase subunits. These results support the interpretation that adding MPA to an E2 treatment complicates cardiovascular injury damage post-MI and therefore contributes to explain the adverse outcome of prospective clinical studies.

A review of the cardiovascular and breast actions of drospirenone in preclinical studies

OBJECTIVE

Hormone therapy is effective for the relief of menopausal symptoms. For women with a uterus, addition of a progestogen is required to protect the endometrium. However, synthetic progestins differ in certain pharmacological characteristics that may have implications for clinical practice. This literature-based review explores differences in the preclinical and clinical profiles of the progestins used in hormone therapy, focusing on their effects on the cardiovascular system and breast.

DESIGN

Studies included are selected based on criteria of relevance, topicality, and subjective assessment of quality, following comprehensive searches of online databases.

RESULTS

The biological actions of progestins depend on their receptor binding affinity profiles as well as their specific effects on progesterone receptor signaling, which often differ based on the ligand. Observational studies indicate that hormone therapies which include medroxyprogesterone acetate and certain other progestins may attenuate the cardiovascular benefits of estrogen and add to risk of breast cancer. Appraisal of the evidence suggests these clinical effects correlate with the progestin's pharmacological profile. Among the newer progestins, drospirenone has been investigated extensively in preclinical studies. With a pharmacological profile similar to progesterone, drospirenone is devoid of estrogenic, androgenic and glucocorticoid activity and possesses potent antialdosterone and antiandrogenic activity. This profile of drospirenone contrasts with that of older progestins, conferring specific effects on cardiovascular and breast cells.

CONCLUSIONS

The relative risks associated with hormone therapy vary with the combination of hormones included. Differences in pharmacological profile among progestins may translate to characteristic divergences in clinical profile, with potential implications for long-term health.

Medroxyprogesterone Abrogates the Inhibitory Effects of Estradiol on Vascular Smooth Muscle Cells by Preventing Estradiol Metabolism

Sequential conversion of estradiol (E) to 2/4-hydroxyestradiols and 2-/4-methoxyestradiols (MEs) by CYP450s and catechol- O -methyltransferase, respectively, contributes to the inhibitory effects of E on smooth muscle cells (SMCs) via estrogen receptor–independent mechanisms. Because medroxyprogesterone (MPA) is a substrate for CYP450s, we hypothesized that MPA may abrogate the inhibitory effects of E by competing for CYP450s and inhibiting the formation of 2/4-hydroxyestradiols and MEs. To test this hypothesis, we investigated the effects of E on SMC number, DNA and collagen synthesis, and migration in the presence and absence of MPA. The inhibitory effects of E on cell number, DNA synthesis, collagen synthesis, and SMC migration were significantly abrogated by MPA. For example, E (0.1μmol/L) reduced cell number to 51±3.6% of control, and this inhibitory effect was attenuated to 87.5±2.9% by MPA (10 nmol/L). Treatment with MPA alone did not alter any SMC parameters, and the abrogatory effects of MPA were not blocked by RU486 (progesterone-receptor antagonist), nor did treatment of SMCs with MPA influence the expression of estrogen receptor-α or estrogen receptor-β. In SMCs and microsomal preparations, MPA inhibited the sequential conversion of E to 2–2/4-hydroxyestradiol and 2-ME. Moreover, as compared with microsomes treated with E alone, 2-ME formation was inhibited when SMCs were incubated with microsomal extracts incubated with E plus MPA. Our findings suggest that the inhibitory actions of MPA on the metabolism of E to 2/4-hydroxyestradiols and MEs may negate the cardiovascular protective actions of estradiol in postmenopausal women receiving estradiol therapy combined with administration of MPA.

Hormonal replacement therapy (HRT) in postmenopause: a reappraisal

Hormone replacement therapy (HRT) is the most effective treatment currently available for vasomotor and urogenital symptoms and decreased libido. Because harmful effects were evidenced in some clinical trials, health authorities now consider that risk-benefit considerations do not favour the use of HRT for prevention of cardiovascular diseases and bone fractures in postmenopausal women. However, experimental and clinical studies indicate that adverse effects of HRT may largely depend on the estrogen and progesterone/progestin formulation, dosage, mode of administration, patient's age, associated diseases, and duration of treatment. All estrogen formulations and modes of administration have similar beneficial effects on vasomotor and urogenital symptoms and on bone structure. But cardiovascular and invasive breast cancer risks are higher with oral estrogen than with transdermal estradiol, and also higher with many progestin compounds than with micronized progesterone. The combination of transdermal estradiol+micronized progesterone appears to be effective and relatively safe if elementary precautions are taken, and seems to be presently the best choice for HRT in most postmenopausal women. In the author's--heterodox--opinion, HRT may also be a good therapeutic choice to prevent bone loss, since alternative medications, including raloxifene and bisphosphonates, may have dramatic harmful effects in some patients. It might also have beneficial effects on the development of coronary disease in young postmenopausal women. HRT requires careful adjustment to each individual patient and continuous monitoring of clinical evolution. In the future, this adjustment could benefit from genetic screening to maximize in each individual the ratio between positive and adverse effects.