Jelica Bjekic-Macut

Dyslipidemia and oxidative stress in PCOS.

Polycystic ovary syndrome (PCOS) is a common metabolic and reproductive disorder in women. An increased cardiovascular risk has to be anticipated in PCOS as it is a metabolically unstable condition. Among cardiovascular risk factors, dyslipidemia is certainly the most persistent and highly prevalent. Predominant observation is an elevation of LDL cholesterol in all PCOS patients. Decreased concentrations of HDL cholesterol are found in obese PCOS from the third decade of life onwards while triglycerides start to rise from the second decade of life. PCOS is associated with oxidative stress, namely increased production of free radicals followed by decreased serum antioxidant levels and antioxidant enzyme activity. Broad range of endocrine and metabolic disturbances like obesity, hyperinsulinemia as well as dyslipidemia might be responsible for PCOS-associated oxidative stress. Therapeutic interventions in PCOS women based on lifestyle modification as well as use of insulin sensitizers did not show significant effect on dyslipidemia. Statins are considered to be a group of promising agents that are safe and effective in improving total cholesterol, LDL cholesterol and triglycerides, and possess antioxidant activity. Supplementation with omega-3 fatty acids, α-lipoic acid and N-acetylcysteine is considered to have an anti-inflammatory and antioxidant effect and to improve dyslipidemia and insulin sensitivity in PCOS women.

Insulin resistance in non-obese women with polycystic ovary syndrome: relation to byproducts of oxidative stress.

To get more insight into molecular mechanisms underlying oxidative stress and its link with insulin resistance, oxidative stress parameters, as well as, antioxidant enzyme activities were studied in young, non-obese women with polycystic ovary syndrome (PCOS). Study was performed in 34 PCOS women and 23 age and body mass index (BMI)-matched healthy controls. Plasma nitrotyrosine and malondialdehyde (MDA), representative byproducts of protein and lipid oxidative damage, were determined by enzyme immunoassay. Antioxidant enzyme activities, superoxide dismutase (SOD) and glutathione peroxidase (GPX) were studied spectrophotometrically. Insulin resistance was calculated using homeostasis assessment model (HOMA-IR). Plasma nitrotyrosine and MDA were increased, but only nitrotyrosine was significantly higher (p < 0.05) in PCOS women compared to controls. Uric acid (surrogate marker of × antine oxidase) was also significantly elevated in PCOS (p < 0.05). Both plasma SOD and GPX activity showed no statistically significant difference between PCOS and controls. Indices of insulin resistance (insulin and HOMAIR) were significantly higher in PCOS group and positively correlated with level of MDA (r = 0.397 and r = 0.523, respectively; p < 0.05) as well as GPX activity (r = 0.531 and r = 0.358, respectively; p < 0.05). Our results indicate that insulin resistance could be responsible for the existence of subtle form of oxidative stress in young, nonobese PCOS women. Hence, presence of insulin resistance, hyperinsulinemia and oxidative damage are likely to accelerate slow development of cardiovascular disease in PCOS.

Effect of hyperglycemia and hyperinsulinemia on glutathione peroxidase activity in non-obese women with polycystic ovary syndrome

OBJECTIVE: In order to gain deeper insight into molecular mechanisms underlying oxidative stress (OS) and its relation to insulin resistance and hyperandrogenemia, plasma markers of OS and antioxidant glutathione-peroxidase (GPX) activity were studied in non-obese polycystic ovary syndrome (PCOS) women via the oral glucose tolerance test (OGTT) and hyperinsulinemic euglycemic clamp. DESIGN: In 36 PCOS women, plasma nitrotyrosine, thiol groups, uric acid (UA) and GPX activity were studied during OGTT and clamp. Insulin resistance was assessed by the homeostasis model (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), Matsuda insulin sensitivity index (ISI) and M/I ratio. RESULTS: In PCOS patients, significant positive correlations were obtained for UA with testosterone (r=0.385, p=0.039) as well as indices of insulin resistance. Acute hyperglycemia during OGTT induced alteration in both OS markers and GPX. The change in nitrotyrosine and GPX during OGTT correlated with testosterone (r=0.543, p=0.036 and r=−0.457, p=0.025, respectively). The most significant association was found between OS markers and ISI. CONCLUSIONS: Our results indicate that non-obese PCOS women are prone to oxidative stress induced by hyperglycemia, but this seems not to be related to the direct effect of hyperinsulinemia during clamp. Oxidative stress markers correlated with indices of insulin resistance and circulating testosterone.

Dihydrotestosterone deteriorates cardiac insulin signaling and glucose transport in the rat model of polycystic ovary syndrome.

It is supposed that women with polycystic ovary syndrome (PCOS) are prone to develop cardiovascular disease as a consequence of multiple risk factors that are mostly related to the state of insulin resistance and consequent hyperinsulinemia. In the present study, we evaluated insulin signaling and glucose transporters (GLUT) in cardiac cells of dihydrotestosterone (DHT) treated female rats as an animal model of PCOS. Expression of proteins involved in cardiac insulin signaling pathways and glucose transporters, as well as their phosphorylation or intracellular localization were studied by Western blot analysis in DHT-treated and control rats. Treatment with DHT resulted in increased body mass, absolute mass of the heart, elevated plasma insulin concentration, dyslipidemia and insulin resistance. At the molecular level, DHT treatment did not change protein expression of cardiac insulin receptor and insulin receptor substrate 1, while phosphorylation of the substrate at serine 307 was increased. Unexpectedly, although expression of downstream Akt kinase and its phosphorylation at threonine 308 were not altered, phosphorylation of Akt at serine 473 was increased in the heart of DHT-treated rats. In contrast, expression and phosphorylation of extracellular signal regulated kinases 1/2 were decreased. Plasma membrane contents of GLUT1 and GLUT4 were decreased, as well as the expression of GLUT4 in cardiac cells at the end of androgen treatment. The obtained results provide evidence for alterations in expression and especially in functional characteristics of insulin signaling molecules and glucose transporters in the heart of DHT-treated rats with PCOS, indicating impaired cardiac insulin action.

Insulin and the polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is the most prevalent endocrinopathy among women during reproductive age. PCOS is characterised by hyperandrogenaemia, hyperinsulinaemia, and deranged adipokines secretion from the adipose tissue. In addition to the reduced insulin sensitivity, PCOS women exhibit β-cell dysfunction as well. Low birth weight and foetal exposure to androgens may contribute to the development of the PCOS phenotype during life. Further metabolic complications lead to dyslipidaemia, worsening obesity and glucose tolerance, high prevalence of metabolic syndrome, and greater susceptibility to diabetes. PCOS women show age-related existence of hypertension, and subtle endothelial and vascular changes. Adverse reproductive outcomes include anovulatory infertility, and unrecognised potentiation of the hormone-dependent endometrial cancer. The main therapeutic approach is lifestyle modification. Metformin is the primary insulin-sensitising drug to be used as an adjuvant therapy to lifestyle modification in patients with insulin resistance and impaired glucose tolerance, as well as in those referred to infertility treatment. Thiazolidinediones should be reserved for women intolerant of or refractory to metformin, while glucagon-like peptide 1 analogues has a potential therapeutic use in obese PCOS women. Randomised clinical trials and repetitive studies on different PCOS phenotypes for the preventive actions and therapeutic options are still lacking, though.

Paradoxical sleep deprivation potentiates epilepsy induced by homocysteine thiolactone in adult rats.

There is an intriguing and still poorly understood relationship between sleep deprivation and epilepsy. It has recently been shown that paradoxical sleep deprivation decreases levels of homocysteine, an amino acid involved together with its thiolactone metabolite in epileptogenesis. The aim of the present study was to investigate the effects of paradoxical sleep deprivation on homocysteine thiolactone (H)-induced seizures in rats, a model of generalized seizures. Selective deprivation of paradoxical sleep in adult male Wistar rats was achieved by the platform method. Animals with implanted electrodes for electroencephalogram (EEG) registration were assigned to appropriate experimental conditions (dry cage for control, large platform for stress control and small platform for paradoxical sleep deprivation) and 72 h later were intraperitoneally treated with either H (5.5 mmol/kg) or saline (0.9% NaCl). This study showed that paradoxical sleep deprivation increased the incidence and number of H-induced seizure episodes, shortened latency time to seizures and led to significant rates of lethality after H administration, but without effect on the seizure severity. Paradoxical sleep deprivation increased the number and duration of spikes-and-wave discharges, while decreased latency to its appearance in EEG. Judging by the behavioral and EEG findings, it could be concluded that paradoxical sleep deprivation can provoke the expression of factors that can potentiate H-induced seizures in adult rats.

Predictors of Subclinical Cardiovascular Disease in Women with Polycystic Ovary Syndrome: Interrelationship of Dyslipidemia and Arterial Blood Pressure

Background. Women with polycystic ovary syndrome (PCOS) could develop subclinical atherosclerosis during life. Purpose. To analyze cardiovascular risk (CVR) factors and their relation to clinical markers of cardiovascular disease (CVD) in respect to their age. Material and Methods. One hundred women with PCOS (26.32 ± 5.26 years, BMI: 24.98 ± 6.38 kg/m2) were compared to 50 respective controls. In all subjects, total cholesterol (TC), HDL-C, LDL-C, triglycerides, TC/HDL-C and TG/HDL-C ratios, glucose, insulin and HOMA index, waist-to-hip ratio (WHR), systolic and diastolic blood pressure (SBP and DBP, resp.), and carotid intima-media thickness (CIMT) were analyzed in respect to their age and level of androgens. Results. PCOS over 30 years had higher WHR (P = 0.008), SBP (P < 0.001), DBP (P < 0.001), TC (P = 0.028), HDL-C (P = 0.028), LDL-C (P = 0.045), triglycerides (P < 0.001), TC/HDL-C (P < 0.001), and triglycerides/HDL-C (P < 0.001) and had more prevalent hypertension and pronounced CIMT on common carotid arteries even after adjustment for BMI (P = 0.005 and 0.036, resp.). TC/HDL-C and TG/HDL-C were higher in PCOS with the highest quintile of FAI in comparison to those with lower FAI (P = 0.045 and 0.034, resp.). Conclusions. PCOS women older than 30 years irrespective of BMI have the potential for early atherosclerosis mirrored through the elevated lipids/lipid ratios and through changes in blood pressure.

MANAGEMENT OF ENDOCRINE DISEASE: Polycystic ovary syndrome and nonalcoholic fatty liver disease

Polycystic ovary syndrome (PCOS) is a frequent endocrine disease in women, with a number of metabolic and reproductive consequences. Obesity, insulin resistance (IR) and type 2 diabetes are prominent metabolic characteristics of PCOS and common factors affecting liver function and generating nonalcoholic fatty liver disease (NAFLD). Multiple genes involved in the synthesis of androgens, cytokines and IR, as well as acquired factors, such as endocrine disruptors, could associate the etiopathogenesis of PCOS and NAFLD. Besides the high prevalence of PCOS in general population, NAFLD was shown to be a frequent condition in transition periods, such as adolescence and menopause. Although liver biopsy is considered to be the gold standard for diagnosing liver damage, its routine use in such a prevalent condition as PCOS can be related to a higher rate of complications. Therefore, it is necessary to be able to diagnose NAFLD using simple and reliable surrogate markers. Recently, fatty liver index and NAFLD fatty liver score analyzed in large cohorts of PCOS women have been shown as accurate markers of liver damage in this metabolically vulnerable population. Lifestyle changes are still the mainstay of the management of NAFLD in PCOS, although prospective randomized controlled clinical studies remain a priority in the field. With regard to medications, metformin may be the drug of choice for treating PCOS patients with NAFLD when pharmacologic therapy is considered. Liraglutide use in obese PCOS has shown favorable effects on the predictors of liver fibrosis. In this review, we aim to summarize the influence of the common risk factors and to discuss the diagnostic approaches and management options for NAFLD in patients with PCOS.

Lipid accumulation product is associated with metabolic syndrome in women with polycystic ovary syndrome

OBJECTIVE There is a need for a simple and accurate method for the assessment of cardiovascular risk in polycystic ovary syndrome (PCOS). Lipid accumulation product (LAP) is based on the assessment of waist circumference and serum triglycerides that yield an estimation of lipid overaccumulation. We aimed to determine whether LAP is associated with metabolic syndrome (MetS) in Caucasian women with PCOS. DESIGN We studied 222 women with PCOS who were diagnosed using the Rotterdam criteria. In all the subjects and controls, LAP was determined and the MetS was assessed using three different international criteria, NCEP-ATP III, IDF, and JIS. ROC curve and logistic regression analyses were performed to determine and analyze associations with the MetS. RESULTS In the study population the prevalence of MetS was 16.2-19.4%. The cut-off value of 25.9 determined that LAP has the strongest association with MetS whichever international criteria are used, followed by HDL (NCEP-ATP III and JIS) and glucose (IDF). CONCLUSIONS LAP is used as an independent clinical indicator for MetS in our PCOS women of Caucasian origin. The high diagnostic accuracy of LAP is superseding the need for the use of multiple clinical indicators for the assessment of lipid accumulation as a prerequisite for diagnosis of metabolic and cardiovascular diseases in PCOS women.

Cardiac Nitric Oxide Synthases and Na + /K + -ATPase in the Rat Model of Polycystic Ovary Syndrome Induced by Dihydrotestosterone

Nitric oxide synthases (NOSs) and Na(+)/K(+)-ATPase are enzymes essential for regular functioning of the heart. Since both enzymes are under insulin and androgen regulation and since insulin action and androgen level were disturbed in polycystic ovary syndrome (PCOS), we hypothesized that cardiac nitric oxide (NO) production and sodium/potassium transport would be deteriorated in PCOS. To test our hypothesis we introduced animal model of PCOS based on dihydrotestosterone (DHT) treatment of female Wistar rats and analyzed protein expression, phosphorylation or subcellular localization of endothelial NOS (eNOS), inducible NOS (iNOS) and alpha subunits of Na(+)/K(+)-ATPase in the heart. Obtained results indicate that DHT treatment significantly decreased cardiac eNOS protein level and activating phosphorylation at serine 1,177, while inhibitory phosphorylation at threonine 495 was increased. In contrast to expression of eNOS, iNOS protein level in the heart of DHT-treated rats was significantly elevated. Furthermore, cardiac protein level of alpha 1 subunit of the ATPase, as well as its plasma membrane content, were decreased in rats with PCOS. In line with this, alpha 2 subunit protein level in fraction of plasma membranes was also significantly below control level. In conclusion, DHT treatment impaired effectiveness of NOSs and Na(+)/K(+)-ATPase in the female rat heart. Regarding the importance of NO production and sodium/potassium transport in the cardiac contraction and blood flow regulation, it implicates strong consequences of PCOS for heart functioning.