A comparison of two progestins on myocardial ischemia???reperfusion injury in ovariectomized monkeys receiving estrogen therapy

Synthesis and Biological Activity of a Bis-steroid-Methanocyclobutanaphthalene- dione Derivative against Ischemia/Reperfusion Injury via Calcium Channel Activation

BACKGROUND

There is some experimental data on the effect exerted by some steroid derivatives against ischemia/reperfusion injury; however, the molecular mechanism is very confusing, perhaps this phenomenon could be due to the protocols used and/or differences in the chemical structure of each one of the steroid derivatives.

OBJECTIVES

The aim of this study was to synthesize a new bis-steroid-methanocyclobutanaphthalene- dione derivative using some tools chemical.

METHODOLOGY

The biological activity exerted by the bis-steroid-methanocyclobutanaphthalene- dione derivative against ischemia/reperfusion injury was evaluated in an isolated heart model using noradrenaline, milrinone, dobutamine, levosimendan, and Bay-K- 8644 as controls. In addition, other alternative experiments were carried out to evaluate the biological activity induced by the bis-steroid-methanocyclobuta-naphthalene-dione derivative against left ventricular pressure in the absence or presence of nifedipine.

RESULTS

The results showed that 1) the bis-steroid-methanocyclobuta-naphthalene-dione derivative significantly decreases the ischemia-reperfusion injury translated as a decrease in the the infarct area in a similar manner to levosimendan drug; 2) both bis-steroidmethanocyclobuta- naphthalene-dione and Bay-K-8644 increase the left ventricular pressure and 3) the biological activity exerted by bis-steroid-methanocyclobuta-naphthalenedione derivative against left ventricular pressure is inhibited by nifedipine.

CONCLUSION

In conclusion, the bis-steroid-methanocyclobuta-naphthalene-dione derivative decreases the area of infarction and increases left ventricle pressure via calcium channels activation; this phenomenon could constitute a new therapy for ischemia/reperfusion injury.

Effects of hormone therapy and dietary soy on myocardial ischemia/reperfusion injury in ovariectomized atherosclerotic monkeys

OBJECTIVE

Hormone therapy (HT) and dietary soy (Soy) inhibit myocardial ischemia/reperfusion (I/R) injury in nonatherosclerotic animals. The aim of this study was to determine their independent and interactive effects on I/R in monkeys previously fed an atherogenic diet for 15 months.

DESIGN

Ovariectomized atherosclerotic monkeys (n = 40) were divided into one of four dietary treatment groups: (1) casein as the protein source, (2) casein and added HT (the equivalent of 5 mug ethinyl estradiol + 1 mg norethindrone acetate daily), (3) Soy protein providing 141 mg total isoflavones daily, or (4) Soy + HT. After 12 months monkeys were anesthetized, and their left anterior descending coronary artery was occluded for 1 hour and reperfused for 4 hours. Infarct size was the percentage of the area at risk not staining with triphenyltetrazolium chloride. Additional measures were myocardial blood flow, stroke volume, coronary output, myeloperoxidase, and malondialdehyde.

RESULTS

There was an interactive negative effect of HT + Soy to increase infarct size from approximately 30% (in other groups) to 55% (P = 0.0004). Additionally, there were negative main effects of Soy on blood flow, coronary output, and stroke volume during I/R (all P values <0.05). There were no effects of treatment on either myeloperoxidase or malondialdehyde.

CONCLUSIONS

Neither HT nor Soy had beneficial effects, whereas their combination had harmful effects, on myocardial I/R injury in monkeys with preexisting atherosclerosis. The mechanism of this negative interaction remains unclear but may relate to Soy's negative effects on hemodynamics.

Sex steroids and cutaneous wound healing: the contrasting influences of estrogens and androgens

The increased prevalence in the elderly of chronic wound-healing conditions, such as venous and diabetic ulceration, is firmly established. This same population additionally suffers from impaired healing of acute wounds, which are characterized by delayed closure, increased local inflammation, and excessive proteolytic activity. In females, this decline in the effectiveness of skin repair mechanisms follows the menopause, and a series of clinical studies has identified estrogens as being endogenous enhancers of healing processes. The administration of 17beta-estradiol, either systemically or topically, has been shown to reverse the fundamental repair defects observed in postmenopausal women. By contrast, androgenic species retard repair and interfere with the accumulation of the structural proteins that reconstitute the damaged dermis. Since estrogen-based hormone replacement therapy produces wide-ranging effects, not all of which are considered to be desirable, more recent studies have sought to identify downstream mediators of estrogenic effects in order to formulate better targeted strategies for improving skin repair in the elderly.

Hormone therapy and cardiovascular risk markers and disease: focus on progestagens

Biological studies have demonstrated estrogen's beneficial effect on cardiovascular risk factors, including plasma lipoproteins, atherogenesis, vascular reactivity, inflammation and antioxidative activity. Additionally, observational studies have supported a cardioprotective effect of hormone therapy (HT), although an underlying healthy-user effect may account for these observations. Progestagens are added to protect against an increased risk of endometrial cancer observed with unopposed estrogen treatment. The inclusion of progestagen in HT has been associated with possible adverse cardiovascular outcomes. Recent, large-scale, randomized clinical studies did not confirm a beneficial cardiovascular effect of HT. On the contrary, an increased risk was found with continuous combined estrogen-progestagen regimens. The progestagen used in these trials was medroxyprogesterone acetate and other progestagen components have only been sparsely elucidated. The purpose of the present review is to outline some of the modifying effects of different progestagens on the actions of estrogen on cardiovascular risk markers and clinical end points observed in biological, observational and clinical studies.