Levente Sára

Arteriolar insulin resistance in a rat model of polycystic ovary syndrome

OBJECTIVE To investigate the vascular dysfunction caused by insulin resistance in polycystic ovary syndrome (PCOS) and the effectiveness of vitamin D in an animal model. DESIGN Controlled experimental animal study. SETTING Animal laboratory at a university research institute. ANIMAL(S) Thirty female Wistar rats. INTERVENTION(S) Rats were divided into groups at age 21-28 weeks. Twenty of them were subjected to dihydrotestosterone (DHT) treatment (83 μg/d); ten of them also received parallel vitamin D treatment (120 ng/100 g/wk). Oral glucose tolerance tests with insulin level measurements were performed. Gracilis arterioles were tested for their contractility as well as their nitric oxide (NO)-dependent and insulin-induced dilation using pressure arteriography. MAIN OUTCOME MEASURE(S) Several physiologic parameters, glucose metabolism, and pressure arteriography. RESULT(S) DHT treatment increased the passive diameter of resistance arterioles, lowered norepinephrine-induced contraction (30.1 ± 4.7% vs. 8.7 ± 3.6%) and reduced acetylcholine-induced (122.0 ± 2.9% vs. 48.0 ± 1.4%) and insulin-induced (at 30 mU/mL: 21.7 ± 5.3 vs. 9.8 ± 5.6%) dilation. Vitamin D treatment restored insulin relaxation and norepinephrine-induced contractility; in contrast, it failed to alter NO-dependent relaxation. CONCLUSION(S) In DHT-treated rats, in addition to metabolically proven insulin resistance, decreased insulin-induced vasorelaxation was observed and was improved by vitamin D treatment without affecting NO-dependent relaxation. The reduction in insulin-induced dilation of arterioles is an important as yet undescribed pathway of vascular damage in PCOS and might explain the clinical effectiveness of vitamin D treatment.

Successful Management of Pregnancy with Nephrotic Syndrome due to Preexisting Membranous Glomerulonephritis: A Case Report

The influence of membranous glomerulonephritis (MGN) on maternal and fetal outcome is controversial, as is the effect of pregnancy on the course of preexisting nephrotic syndrome. We report a case of successful management of a pregnancy with preexisting severe nephrotic syndrome due to biopsy-proven primary MGN. Our patient became pregnant in a non-compliance period, discontinued the nephrological follow-up program and her kidney disease decompensated. From the 22nd gestational week the patient was treated with intermittent pulses of methylprednisolone (250 mg i.v.) and a maintenance dose of 32–64 mg/day orally, along with azathioprine 100 mg/day. She also received antihypertensive, diuretic, and anticoagulant therapy, and supplementation with fresh frozen plasma and albumin. In the 33rd gestational week a cesarean section was performed due to deteriorating creatinine clearance, low serum total protein levels, increasing edema and progression of intrauterine growth retardation of the fetus. Three months after delivery, the patient’s renal disease went into complete remission. To our knowledge, this is the first report of using azathioprine during pregnancy with severe nephrotic syndrome due to primary MGN.

Effects of vitamin D3 derivative – calcitriol on pharmacological reactivity of aortic rings in a rodent PCOS model

BACKGROUND The aim of this study was to examine the effects of the hyperandrogenic state in dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS), the vascular responses to different vasoactive agents, and the modulatory role of vitamin D3. METHODS APCOS model was induced by DHT application in 20 female Wistar rats. Ten of the DHT treated rats simultaneously received calcitriol treatment. After 10 weeks, myographs were used to test the reactivity of isolated thoracic aortic rings to norepinephrine and acetylcholine. Thereafter, the vascular rings were incubated with the NO-synthase blocker (nitro-L-arginine methyl ester) or the cyclooxygenase inhibitor (indomethacin) for 20 min, and the effects of norepinephrine and acetylcholine were re-evaluated. RESULTS Norepinephrine-induced vasoconstriction was enhanced after DHT treatment, but this effect was attenuated by calcitriol administration. Vasorelaxation of DHT-treated thoracic aortic rings was impaired, but this could be partly reversed by calcitriol application. Impaired NO-dependent vasorelaxation in DHT-treated animals was mostly reversed by concomitant calcitriol administration, but this effect was diminished by prostanoid-dependent vasoconstriction. CONCLUSIONS These studies show that the enhanced sensitivity to vasoconstrictors and impaired NO-dependent vasorelaxation in hyperandrogenic PCOS rats could be partially reversed by calcitriol treatment.

Pharmacological reactivity of resistance vessels in a rat PCOS model – vascular effects of parallel vitamin D3 treatment

The aim of this study was to clarify the effects of dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS) on pharmacological reactivity of a resistance vessel in a rat model and the possible modulatory role of 1,25-(OH)2-cholecalciferol (vitamin D3). The PCOS model was induced in adolescent female Wistar rats by a 10-week DHT treatment. Norepinephrine induced contractility and acetylcholine relaxation were tested in arterioles by pressure arteriography in control as well as DHT- and DHT plus vitamin D3-treated (DHT+D3) animals. Decreased vasoconstriction and dilatation were detected after DHT treatment. Concomitant vitamin D3 treatment increased the contractile response and resulted in more relaxed vessels. Endothelial dilation tested with acetylcholine was lower after DHT treatment, this effect was not depend on vitamin D3 supplementation. In conclusion, hyperandrogenic state resulted in reduced endothelium- and smooth muscle-dependent vasorelaxation and constriction with a complete loss of nitric oxide (NO)-dependent relaxation compared with controls. These alterations caused by chronic DHT treatment were partially reversed by concomitant vitamin D3 administration.

Arteriolar biomechanics in a rat polycystic ovary syndrome model - effects of parallel vitamin D3 treatment.

UNLABELLED To clarify the effects of dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS) on arteriolar biomechanics in a rat model and the possible modulatory role of vitamin D3. METHODS AND RESULTS The PCOS model was induced in female Wistar rats by ten-weeks DHT treatment. Arteriolar biomechanics was tested in arterioles by pressure arteriography in control as well as DHT- and DHT with vitamin D3-treated animals in contracted and passive conditions. Increased wall stress and distensibility as well as increased vascular lumen were detected after DHT treatment. Concomitant vitamin D3 treatment lowered the mechanical load of the arterioles and restored the vascular diameter. CONCLUSION The hyperandrogenic state resulted in more rigid, less flexible arteriolar walls with increased vascular lumen compared with controls. DHT treatment caused eutrophic remodelling of gracilis arteriole. These prehypertensive alterations caused by chronic DHT treatment were mostly reversed by concomitant vitamin D3 administration.

Lower-limb veins are thicker and vascular reactivity is decreased in a rat PCOS model: concomitant vitamin D3 treatment partially prevents these changes

Polycystic ovary syndrome (PCOS) causes vascular damage to arteries; however, there are no data for its effect on veins. Our aim was to clarify the effects of dihydrotestosterone (DHT)-induced PCOS both on venous biomechanics and on pharmacological reactivity in a rat model and to test the possible modulatory role of vitamin D3 (vitD). PCOS was induced in female Wistar rats by DHT treatment (83 μg/day, subcutaneous pellet). After 10 wk, the venous biomechanics, norepinephrine (NE)-induced contractility, and acetylcholine-induced relaxation were tested in saphenous veins from control animals and from animals treated with DHT or DHT with vitD using pressure angiography. Additionally, the expression levels of endothelial nitric oxide synthase (eNOS) and cyclooxygenase (COX-2) were measured using immunohistochemistry. Increased diameter, wall thickness, and distensibility as well as decreased vasoconstriction were detected after the DHT treatment. Concomitant vitD treatment lowered the mechanical load on the veins, reduced distensibility, and resulted in vessels that were more relaxed. Although there was no difference in the endothelial dilation tested using acetylcholine (ACh), the blocking effect of N(G)-nitro-l-arginine methyl ester (l-NAME) was lower and was accompanied by lower COX-2 expression in the endothelium after the DHT treatment. Supplementation with vitD prevented these alterations. eNOS expression did not differ among the three groups. We conclude that the hyperandrogenic state resulted in thicker vein walls. These veins showed early remodeling and altered vasorelaxant mechanisms similar to those of varicose veins. Alterations caused by the chronic DHT treatment were prevented partially by concomitant vitD administration.

Altered insulin-induced relaxation of aortic rings in a dihydrotestosterone-induced rodent model of polycystic ovary syndrome

OBJECTIVE To clarify the effects of dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS) on the insulin-dependent vasodilatation of the thoracic aorta and the role of vitamin D in a rat model. DESIGN Controlled experimental animal study. SETTING Laboratory. ANIMAL(S) Thirty adolescent female Wistar rats. INTERVENTION(S) The PCOS model was induced by 10 weeks of DHT treatment (83 μg/d). One-half of the DHT-treated animals also received vitamin D (120 ng/kg/wk). MAIN OUTCOME MEASURE(S) The aortic rings of the control, DHT, and DHT plus vitamin D-treated animals were isolated. The insulin-dependent vasodilation of the isolated aortic rings was compared in Krebs-Ringer solution and under blockade of nitric oxide (NO) synthase or cyclooxygenase. RESULT(S) The insulin-dependent vasorelaxation decreased in both DHT-treated groups independently from the vitamin D treatment; NO-dependent and -independent relaxations were both impaired. In response to prostanoid, vasoconstriction was increased after DHT treatment. The NO-independent relaxation was partially improved by vitamin D treatment, which was neutralized by increased prostanoid-dependent vasoconstriction. CONCLUSION(S) Previously, we found that vitamin D treatment prevented systemic insulin resistance; however, in this study, we did not detect any influence on the vascular insulin resistance of the aorta that was induced by DHT treatment. Consequently, controlling insulin resistance with vitamin D alone did not resolve the aortic endothelial dysfunction caused by the hyperandrogenic state.

Depressed calcium cycling contributes to lower ischemia tolerance in hearts of estrogen-deficient rats.

ObjectiveEstrogens enhance ischemia tolerance (IT) in the myocardium, the mechanism of which remains unclear. We investigated the effects of long-term estrogen deprivation on the intracellular calcium (Ca2+i) transient of the heart and its possible influence on IT. MethodsHearts of ovariectomized (OVX) and sham-operated (control) adult female rats (some receiving estrogen therapy) were studied 10 weeks after surgical operation: control (n = 8), OVX (n = 10), sham-operated estrogen-substituted (n = 7), and ovariectomized estrogen-substituted (n = 9). In vivo heart function was assessed by echocardiography, whereas Ca2+i transients were recorded, concomitantly with left ventricular pressure and coronary flow, by Indo-1 surface fluorometry in isolated Langendorff-perfused hearts. Isolated hearts were subjected to a 30-minute global ischemia–30-minute reperfusion protocol. Left ventricular expression of myocardial sarcoendoplasmic reticulum Ca2+-ATPase (SERCA2a), phospholamban (PLB), and Ser16-phosphorylated PLB was measured. ResultsOvariectomy did not influence resting cardiac function in vivo or ex vivo. However, Ca2+ removal was slower. During ischemia, Ca2+i elevation and ischemic contracture were more pronounced after ovariectomy. Postischemic restitution of inotropic function (developed pressure; +dP/dtmax) and lusitropic function (−dP/dtmax) and Ca2+i transient recovery (amplitude; ±dCa2+i/dtmax) were decreased in OVX hearts. Sarcoendoplasmic reticulum Ca2+-ATPase expression was unaltered, whereas PLB and Ser16-phosphorylated PLB levels were higher after ovariectomy. All effects of ovariectomy were restored by estrogen therapy. ConclusionsOvariectomy impairs myocardial Ca2+ removal by increasing the expression of the SERCA2a inhibitor PLB. Defective Ca2+ transport causes ischemic Ca2+i overload and insufficient postischemic recovery of Ca2+i transients, which entail depressed hemodynamic restitution. Protection of intact Ca2+ cycling in the myocardium by estrogens plays a major role in enhancing IT.

Antioxidant effect of the active metabolites of tibolone

Abstract Certain steroidal compounds have an antioxidant effect in humans. Our aim was to test whether the synthetic steroid tibolone and its metabolites are also able to display such a property. For this, granulocytes from healthy men and women were incubated for two hours with different concentrations (10−7, 10−8, 10−9 M) of either estradiol, tibolone, 3α-hydroxytibolone, 3β-hydroxytibolone, Δ4-tibolone, 3α-sulfated-tibolone, 3α-17β-disulfated-tibolone, 3β-sulfated-tibolone or 3β-17β-disulfated-tibolone. Superoxide anion generation of neutrophils was measured by photometry. Results of different steroids were given as percentages of their controls. A more simple superoxide generating system, the xanthine–xanthine oxidase reaction was also tested. We found that granulocyte superoxide production did not differ from the control using 10−9 M of steroids. Using 10−8 M concentration: estradiol (80.9 ± 2.5%); 3β-sulfated-tibolone (83.3 ± 4.7%); 3β-17β-disulfated-tibolone (81.0 ± 4.2%) caused a significant decrease in superoxide production, compared to the control. In addition at 10−7 M, 3β-hydroxytibolone and 3α-sulfated-tibolone also showed antioxidant effects. In the xanthine–xanthine oxidase system estradiol (67.4 ± 1.0%), 3α-sulfated-tibolone (85.8 ± 5.3%), 3α-17β-disulfated-tibolone (71.9 ± 2.5%), 3β-sulfated-tibolone (73.9 ± 5.0%), and 3β-17β-disulfated-tibolone (65.8 ± 3.4%) caused a significant decrease in superoxide production. Conclusively, although tibolone itself did not show significant antioxidant capacity, most of its active metabolites have antioxidant effects.

Ultrasonography in the diagnosis of ovarian and endometrial carcinoma

Transvaginal sonography has become a crucial part of the routine gynecologic examination. It offers now a great help in the diagnosis of almost all gynecological diseases. Transvaginal ultrasound means the first step in the diagnosis of the first two most common gynecological malignancies, and in many cases we are able to set up a diagnosis of its own. The purpose of this article is to emphasize the significant role of transvaginal ultrasonography in the diagnosis of these two dieseases mentioned above, with summarizing the latest developments regarding the capabilities of sonography (Doppler-technique, three-dimensional ultrasonograpy).