Non-alcoholic fatty liver disease is associated with insulin resistance and lipid accumulation product in women with polycystic ovary syndrome

STUDY QUESTION

What are the most relevant factors associated with non-alcoholic fatty liver disease (NAFLD) in women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Insulin resistance (IR) and lipid accumulation product (LAP) are independently associated with NAFLD in PCOS.

WHAT IS KNOWN ALREADY

Obesity and IR are frequently present in both women with PCOS and subjects having NAFLD. The coexistence of PCOS and NAFLD might synergistically increase the risk for both type 2 diabetes (T2DM) and cardiovascular disease (CVD). LAP, calculated from waist circumference (WC) and triglycerides (TGs) concentrations [(WC-58) × TGs], has been shown to represent an integrated marker of cardiometabolic risk in women with PCOS.

STUDY DESIGN, SIZE, DURATION

This cross-sectional study included 600 Caucasian women diagnosed with PCOS by the Rotterdam criteria between May 2008 and May 2013.

PARTICIPANTS, SETTINGS, METHODS

The study was done at the university hospitals in Belgrade, Serbia and Thessaloniki, Greece. All subjects underwent anthropometric measurements and analyses of fasting blood glucose, insulin, lipids, total testosterone and SHBG, as well as liver tests (transaminases, γ-glutamyltransaminase, total bilirubin and alkaline phosphatase). Calculations for a NAFLD liver fat score (NAFLD-LFS) (with, accordingly, determination of metabolic syndrome and testing for T2DM) as well as homeostasis model assessment of IR (HOMA-IR), LAP as a marker of visceral adiposity, and free androgen index (FAI) were performed. We evaluated the prevance of NAFLD and analyzed associations of the above variables with NAFLD.

MAIN RESULTS AND THE ROLE OF CHANCE

NAFLD was more prevalent in patients with PCOS than in controls (50.6 versus 34.0%, respectively). Women with PCOS had higher readings for WC, LAP, insulin and HOMA-IR, total cholesterol and TGs than controls (P < 0.001). In PCOS women, the NAFLD-LFS significantly (P < 0.001) correlated with WC, BMI, glucose, HOMA-IR, TGs, LAP and FAI. In multivariate logistic regression, HOMA-IR and LAP were independently associated with NAFLD (P ≤ 0.001).

LIMITATIONS, REASONS FOR CAUTION

A possible weakness of the study may be the absence of structural confirmation of liver status. Hovewer, liver biopsy is invasive, difficult to perform in large populations and carries some risk of complications while magnetic resonance spectroscopy does not provide any information regarding the presence of fibrosis and is not routinely available. Another possible limitation could be the measurement of total testosterone by radioimmunoassay, which can be inaccurate when determining low levels of testosterone. Finally, fewer controls than subjects in the study group could have affected the significance of the results.

WIDER IMPLICATIONS OF THE FINDINGS

There is a debate on the most accurate clinical method for diagnosing liver disease as an early predictor of T2DM and CVD in general population and in PCOS women. There current study provided data on this issue from a cohort of Caucasian women with PCOS.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by a research grant by the Serbian Ministry of Science and Education (grant nos 41009 and 175032). All authors have no competing interests.

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.

Growth hormone secretion after the administration of GHRP-6 or GHRH combined with GHRP-6 does not decline in late adulthood

OBJECTIVE

Growth hormone (GH) secretion in middle and late adulthood declines with age. However, the precise mechanisms causing this impairment in GH release are unknown. His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6) is a synthetic compound that releases GH in a dose related and specific manner in several species, including man. In order to gain a further insight into disrupted GH secretion in late adulthood, we evaluated GH responses to GHRP-6 or GHRH, administered either alone or in combination, in healthy young and late adulthood groups of subjects.

DESIGN

All subjects underwent three different tests carried out in random order and separated by at least one week. Tests were performed at 0900 h after an overnight fast. GHRH (100 micrograms), GHRP-6 (90 micrograms) either alone or in combination were administered as an i.v. bolus.

SUBJECTS

Groups of healthy young (mean +/- SEM 22 +/- 1.1 years, n = 9) and older adult subjects (59.5 +/- 1.7 years, n = 9) were studied.

MEASUREMENTS

Serum GH levels were measured by radioimmunoassay.

RESULTS

In the group of young adult subjects the combined administration of GHRH and GHRP-6 elicited a greater GH increase than GHRH alone (F = 21.9, P < 0.001) or GHRP-6 alone (F = 6.2, P = 0.01). Similarly, the response to the combined stimuli was also greater than with GHRH alone (F = 21.8, P < 0.001) or GHRP-6 alone (F = 23.9, P < 0.001) in the late adulthood group of subjects. GH responses to GHRH were greater in younger than in older subjects (F = 3.45, P = 0.03). In contrast, GH responses to either GHRP-6 (F = 0.71, P = NS) or combined GHRH plus GHRP-6 administration (F = 0.68, P = NS) were not significantly different between the two groups.

CONCLUSIONS

These data show that GH responses to GHRP-6 are much greater than to GHRH in late adulthood. The marked increase of plasma GH levels observed after administration of GHRP-6 alone or in combination with GHRH indicates that impaired GH secretion in late adulthood is a functional and potentially reversible state.

White Addison's disease: what is the possible cause?

A case of chronic primary adrenal insufficiency without hyperpigmentation in a 64-year-old woman is reported. Due to the absence of hyperpigmentation the diagnosis was delayed and she became critically ill. During endocrine evaluation, in order to investigate the mechanism responsible for the absence of hyperpigmentation, skin biopsy was done and hormones responsible for the skin pigmentation were measured. Absence of hyperpigmentation is explained by high degree of melanosome degradation in secondary lysosomes called "compound melanosomes", which overwhelmed increased stimulation of the skin pigmentation. Melanocyte-stimulating hormones were elevated with a strikingly high beta-LPH/ACTH ratio. To our knowledge, this is the first study of pathogenic mechanisms responsible for the absence of hyperpigmentation in white Addison's disease.

Cardiovascular risk factors and events in women with androgen excess

Androgen excess (AE) was approximated to be present in 7% of the adult population of women. Polycystic ovary syndrome (PCOS) is the most prevalent among them, followed by idiopathic hirsutism (IH), congenital adrenal hyperplasia (CAH), hyperandrogenic insulin-resistant acanthosis nigricans (HAIRAN) syndrome, and androgen-secreting neoplasms (ASNs). Increased cardiovascular risk was implicated in women with AE. Serum testosterone independently increases risk for cardiovascular disease (CVD), and correlates even with indices of subclinical atherosclerosis in various populations of postmenopausal women. Hyperandrogenism in PCOS is closely related to the aggravation of abdominal obesity, and together with insulin resistance forming the metabolic core for the development of CVD. However, phenotypic variability of PCOS generates significant influence on the cardiometabolic risks. Numerous risk factors in PCOS lead to 5-7 times higher risk for CVD and over 2-fold higher risk for coronary heart disease and stroke. However, issue on the cardiometabolic risk in postmenopausal women with hyperandrogenic history is still challenging. There is a significant overlapping in the CVD characteristics of women with PCOS and variants of CAH. Relevant clinical data on the prevalence and cardiometabolic risk and events in women with IH, HAIRAN syndrome or ASNs are scarce. The effects of various oral contraceptives (OCs) and antiandrogenic compounds on metabolic profile are varying, and could be related to the selected populations and different therapy regiments mainly conducted in women with PCOS. It is assumed relation of OCs containing antiandrogenic progestins to the increased risk of cardiovascular and thromboembolic events.

Leptin levels and insulin sensitivity in obese and non-obese patients with polycystic ovary syndrome

The study was conducted to assess leptin levels and insulin sensitivity in obese and non-obese patients with polycystic ovary syndrome (PCOS). Twenty-two women with PCOS and 19 control healthy women were included in the study, divided into obese and non-obese groups. Leptin was determined using Linco Research radio-immunoassay while insulin sensitivity was calculated from intravenous glucose tolerance tests with frequent blood sampling using MINMOD analysis. Significantly higher basal leptin levels were found in obese compared to non-obese PCOS (31.76 +/- 3.06 vs. 10.42 +/- 2.31 ng/ml; p < 0.05) as well as in obese in comparison to non-obese controls (29.16 +/- 5.06 vs 8.51 +/- 0.88 ng/ml; p < 0.05). A negative correlation was found between insulin sensitivity and leptin levels in both obese (r = -0.2480; p > 0.05) and non-obese PCOS groups (r = -0.4620; p > 0.05). In conclusion, high serum leptin, insulin and testosterone levels together with reduced insulin sensitivity were found in obese PCOS women, suggesting that high leptin levels could be a characteristic of the obese PCOS phenotype.

The effect of metformin and myoinositol on metabolic outcomes in women with polycystic ovary syndrome: role of body mass and adiponectin in a randomized controlled trial

PURPOSE

To compare the effects of insulin sensitizers metformin (MET) and myo-inositol (MI) on adiponectin levels and metabolic characteristics in women with polycystic ovary syndrome (PCOS) with respect to their body mass index (BMI).

METHODS

In this open label, parallel randomized clinical trial, 66 women with PCOS (33 normal-weight and 33 overweight/obese) were randomized to either MI (4 g/day) or MET (1500 mg/day) for a period of 6 months. Serum concentration of adiponectin, hormonal and metabolic laboratory outcomes and clinical assessment of BMI, body composition and Ferriman-Gallwey score (FG score) were evaluated before and after treatment.

RESULTS

After the 6-month intervention, comparison between MET and MI in time to treatment analysis showed no significant differences between the two treatments for all analyzed parameters. Only borderline significantly lower AUC glucose was found in the MET group in comparison to the MI group (p = 0.071). The main effect of treatment was shown for glucose concentration at 120 min OGTT (p = 0.032) and testosterone (p = 0.002). The main effect of time was shown for body mass (p = 0.004), waist circumference (p < 0.001), BMI (p = 0.003), body fat mass (p = 0.001), adiponectin (p = 0.020), fasting glucose (p = 0.001), testosterone (p = 0.015), SHBG (p = 0.013), 17OH progesterone (p = 0.008), LH (p = 0.004) and estradiol (p = 0.014).

CONCLUSION

Our study showed similar effects of MET and MI on BMI, body composition, hormonal profile, metabolism of glucose and insulin, and adiponectin level. The two insulin sensitizers, MET and MI, were useful in reducing BMI and improving body composition without significant differences between the two treatments in PCOS women.

TRIAL REGISTRATION

ISRCTN13199265. Trial registration date: 14.04.2021. (ISRCTN Registry), retrospectively registered.

Hypothalamic-Pituitary-Adrenocortical Axis Hypersensitivity and Glucocorticoid Receptor Expression and Function in Women with Polycystic Ovary Syndrome

Molecular mechanisms underlying pathophysiology of polycystic ovary syndrome (PCOS), especially those related to cortisol signaling, are poorly understood. We hypothesized that modulation of glucocorticoid receptor (GR) expression and function, may underlie possible PCOS-related impairment of feedback inhibition of hypothalamic-pituitary-adrenocortical (HPA) axis activity and thus contribute to increased adrenal androgen production in women with PCOS.

24 normal-weight and 31 obese women with PCOS were compared to 25 normal-weight controls. Fasting blood samples were collected for measurements of serum concentrations of dehydroepiandrosterone sulfate, testosterone, sex hormone-binding globulin, insulin, basal cortisol and cortisol after oral administration of 0.5 mg dexamethasone. Concentrations of GR mRNA, GR protein, mineralocorticoid receptor (MR) protein and heat shock proteins (Hsps), as well as the number of GR per cell (Bmax) and its equilibrium dissociation constant (KD) were measured in isolated peripheral blood mononuclear cells.

An increase in HPA axis sensitivity to dexamethasone, an elevation of the GR protein concentration, and unaltered receptor functional status were found in both normal-weight and obese women with PCOS vs. healthy controls. Lymphocyte MR, Hsp90 and Hsp70 concentrations, and MR/GR ratio were similar in all groups. Correlation between Bmax and KD was weaker in the group of obese women with PCOS than in the other 2 groups.

The results did not confirm the initial hypothesis, but imply that PCOS is associated with increased GR protein concentration and HPA axis sensitivity to dexamethasone.

Is there a role for leptin in human reproduction?

Leptin is a protein product from the obesity gene (ob gene). It has been shown that leptin significantly correlates with body mass index in humans. In contrast to the obesity of genetically obese (ob/ob) mice, human obesity is not generally caused by gene mutations. It is possible that human obesity results from central leptin resistance. Leptin can serve as a metabolic cue in the neuronal activation of gonadotropin releasing hormone (GnRH) at the end of the prepubertal period. The concentration of leptin is higher in pubertal girls than pubertal boys, and it is supposed that sexual dimorphism might be established in the prepubertal period or even in earlier developmental phases. This dimorphism could be explained by a suppressive action of androgens on leptin. Decreased leptin levels were found in undernourished women of reproductive age, mainly presenting with oligo- or amenorrhea. Leptin concentrations fluctuate according to the phase of the menstrual cycle. It is suggested that the complex relationship of leptin with other hormones, such as insulin, can have etiopathogenetic importance in some enigmatic reproductive disturbances such as the polycystic ovary syndrome. Recent findings of leptin in non-adipose tissue of the placenta could indicate its potential role in developmental physiology and human reproduction.

Growth hormone response to GHRH, GHRP-6 and GHRH + GHRP-6 in patients with polycystic ovary syndrome

OBJECTIVE

Despite improved diagnostic facilities and advanced in vitro studies, the primary causes of the polycystic ovary syndrome (PCOS) have not been resolved. A defect in the regulation of GH secretion has been suggested in PCOS but the available data are limited and the underlying mechanisms remain unknown. In recent years considerable attention has been devoted to non-classic GH secretagogues and, in particular, to the series of hexapeptides of which GH-releasing peptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, known as GHRP-6) is the most representative. GHRP-6 seems to be a promising tool for exploring GH secretory mechanisms and it has been reported that GHRH + GHRP-6 is a powerful stimulus to GH secretion. Our aim was to investigate the GH responses to GHRH, GHRP-6 and the administration of GHRP + GHRP-6 in two groups of patients (normal weight and obese) with PCOS in comparison with matched control groups.

DESIGN

All subjects were studied three times on different days with GHRH (100 micrograms i.v.), GHRP-6 (90 micrograms i.v.) and GHRH + GHRP-6 (100 micrograms + 90 micrograms).

PATIENTS

Sixteen women with PCOS and 22 healthy controls were studied. They were divided into four groups according to BMI: Group A (non-obese PCOS, n = 6, age 21.8 +/- 1.7 years, BMI 22.1 +/- 0.8 kg/m2); Group B: (obese PCOS, n = 10, age 21.7 +/- 1.3 years, BMI 32.9 +/- 2.1 kg/m2); Group C (non-obese healthy women, n = 13, age 26.8 +/- 1.5 years, BMI 21.8 +/- 0.6 kg/m2) and Group D (obese healthy women, n = 9, age 29.4 +/- 4.2 years, BMI 35.7 +/- 1.3 kg/m2).

MEASUREMENTS

Serum GH was measured using a time-resolved fluoroimmunoassay (Delphia, Pharmacia).

RESULTS

After GHRH administration significant differences were found between GH peaks in Groups A and B (82.4 +/- 16.4 vs 20 +/- 4.9 mU/l, P < 0.05) and in AUC for GH between Groups A and B (4667 +/- 1061 vs 947 +/- 236, P < 0.05) while there were no differences between the same groups in GH peak or AUC after GHRP-6 administration. There were no significant differences in peaks or AUC for GH after GHRH between Groups A and C, nor between Groups B and D. There were significant differences in GH peaks after combined administration of GHRH + GHRP-6 between Groups A and B (211 +/- 26.4 vs 108 +/- 17.6, P < 0.05) as well as between GH AUC in Groups A and B (12068 +/- 2323 vs 5997 +/- 1342, P < 0.05). There were no differences in GH peaks or AUC for GH after GHRH + GHRP-6 administration between Groups A and C or Groups B and D.

CONCLUSIONS

The impaired GH response to GHRH found in obese PCOS patients is a consequence of obesity and could be a functional defect, since it can be overridden with GHRP-6 administration.

Growth hormone (GH) response to GH-releasing peptide-6 and GH-releasing hormone in normal-weight and overweight patients with non-insulin-dependent diabetes mellitus

The growth hormone (GH) response to GH-releasing hormone (GHRH) in patients with non-insulin-dependent diabetes mellitus (NIDDM) was found to be either decreased or normal. The recent introduction of a new and potent GH stimulus, GH-releasing peptide-6 (GHRP-6), allowed further investigation of the functional properties of somatotropes in a variety of metabolic diseases. The aim of the present study was to investigate the response of GH to GHRP-6, GHRH, and GHRP-6 + GHRH in NIDDM patients. Twenty-one patients with NIDDM were divided into two groups: group A, normal weight (body mass index [BMI], 23.31+/-0.62 kg/m2); and group B, overweight (BMI, 27.62+/-0.72 kg/m2). Eight normal-weight control subjects (group C) were studied. Each subject received GHRP-6 (90 microg intravenously [i.v.]), GHRH (100 microg i.v.), and GHRP-6 + GHRH on three separate occasions. There was no difference between the GH response after GHRP-6 in groups A, B, and C in terms of the GH peak (50.95+/-11.55, 51.96+/-7.71, and 70.07+/-15.59 mU/L, P>.05) and the area under the curve (AUC) for GH (2,340.06+/-617.36, 2,684.54+/-560.57, 3,462.78+/-1,223.53 mU/L/120 min, P>.05). A decreased GH response to GHRH was found in group B in comparison to group A (B v A: peak GH response, 8.25+/-1.90 v 22.19+/-8.81, P<.05; AUC GH, 479.62+/-84.0 v 1,443.21+/-743.76, P<.05). There was no difference in the GH response between group A and group C (peak GH response, 22.19+/-8.81 v 26.42+/-6.71, P>.05; AUC, 1,443.21+/-743.76 v 1,476.51+/-386.56, P>.05). There was a significant difference between the same parameters in group B versus group C (8.25+/-1.90 v 26.42+/-6.71, P<.05; AUC, 479.62+/-84.0 v 1,476.51+/-386.56, P<.05). The combined administration of GHRP-6 + GHRH elicited a synergistic GH response in NIDDM patients and controls. There was a significant difference between groups A and B for the GH peak (96.49+/-9.80 v 68.38+/-8.25, P<.05), whereas there was no difference for the AUC (5,111.13+/-703.77 v 3,425.95+/-459.67, P>.05). There was no difference in the peak GH after the combined test between group A and group C (96.49+/-9.80 v 139.82+/-24.16, P>.05), whereas the peak GH in the same test was significantly decreased in group B in comparison to group C (68.38+/-8.25 v 139.82+/-24.16, P<.05). The AUC for GH after combined GHRP-6 + GHRH in group A versus group C was not significantly different (5,111.13+/-703.77 v 9,274.71+/-1,541.46, P>.05), whereas there was a significant difference for the same test between group B and group C (3,425.95+/-459.67 v 9,274.71+/-1,541.46, P<.05). Our results demonstrate that normal-weight NIDDM patients have a preserved GH response to GHRP-6, GHRH, and GHRP-6 + GHRH, and overweight NIDDM patients have a blunted response to GHRH and GHRP-6 + GHRH. The preserved GH response to GHRP-6 in both diabetic groups suggests that the secretory potential of somatotropes is preserved in NIDDM patients. The impairment of the GH response to GHRH in overweight NIDDM patients could be a functional defect due to the obesity, since it could be overridden by administration of GHRP-6.

Ovulation induction and early pregnancy loss in a woman susceptible to autoimmune diseases: a possible interrelationship

We report a 34-year-old woman with sequentially occurring autoimmune diseases that are possibly triggered by numerous ovulation inductions. At the ages of 26-32 years, she experienced 27 uncontrolled ovulation induction cycles using clomiphene citrate (CC) or CC plus human menopausal gonadotropin plus human chorionic gonadotropin. She became pregnant at the ages of 27, 30 and 31 with subsequent pregnancy loss in the 28th, 8th and 10th week of gestation, respectively. Insulin-dependent diabetes mellitus (IDDM) developed at the age of 28. During the second year of ovulation induction, at the age of 27, she developed arthralgia that worsened and became migratory from the age of 31. Thrombocytopenia appeared at the age of 33. The diagnosis of systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) was established at the age of 34. To the best of our knowledge, this is the first case of concurrent IDDM, SLE and APS in a patient associated with ovulation inductions. Excessive levels of estradiol achieved during the ovulation inductions could play a role in the expression of multiple autoimmune diseases in the susceptible woman.

Exercise decreases susceptibility to homocysteine seizures: the role of oxidative stress

The aim of the study was to examine the effects of chronic exercise training on seizures induced by homocysteine thiolactone (HCT) in adult rats. Rats were assigned to: sedentary control; exercise control; sedentary+HCT; exercise+HCT group. Animals in the exercise groups ran 30 min daily on a treadmill for 30 consecutive days (belt speed 20 m/min), while sedentary rats spent the same time on the treadmill (speed 0 m/min). On the 31st day, the HCT groups received HCT (8.0 mmol/kg), while the control groups received vehicle. Afterwards, convulsive behavior and EEG activity were registered. Lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) activity were ascertained in the rat hippocampus. No signs of seizures were registered in sedentary and exercise control rats. Seizure latency was increased, while number of seizure episodes and spike-and-wave discharges (SWD) in EEG were decreased in the exercise+HCT compared to the sedentary+HCT group. Seizure incidence, the severity thereof and duration of SWDs were not significantly different between these groups. Exercise partly prevented increase of lipid peroxidation and decrease of the SOD and CAT activity after HCT administration. These results indicate beneficial effects of exercise in model of HCT-induced seizures in rats, what could be, at least in part, a consequence of improved antioxidant enzymes activity.

Insulin resistance, androgens, and lipids are gradually improved in an age-dependent manner in lean women with polycystic ovary syndrome: insights from a large Caucasian cohort

PURPOSE

Polycystic ovary syndrome (PCOS), considered a lifelong condition, manifests mainly as a cluster of hyperandrogenic symptoms during the early reproductive years, with the affected woman gradually developing an adverse cardiometabolic profile over the years. However, some data point to the possibility of differences in the evolution of PCOS according to a woman's weight. The aim of the present study was to evaluate the metabolic and hormonal profiles of women with PCOS over time.

METHODS

A total of 763 lean women with PCOS (BMI 20-25 kg/m²) and 376 controls were included. The study group was further divided into three age groups representing women post-adolescence, of reproductive age, and of late reproductive age. All subjects were assessed clinically, biochemically, and hormonally.

RESULTS

Waist circumference, lipids, androgens, and insulin resistance index (homeostasis model assessment of IR index (HOMA-IR)) were significantly higher in the PCOS group compared with controls. Age subgroup analysis showed a progressive decrease of HOMA-IR and waist circumference, and lipid levels were comparable between PCOS and controls in all age groups. Androgens remained significantly higher in PCOS, but they gradually decreased through time. A significant negative association of age with waist circumference, androgens, insulin, and HOMA-IR was revealed. Univariate and multivariate regression analysis disclosed a strong correlation of HOMA-IR with age (p = 0.014, β - 0.19, SE coefficient 0.008) as a single parameter or in combination with total cholesterol (TC) (p < 0.001, age: β - 0.023, SE 0.10; TC: β 0.084, SE 0.027).

CONCLUSION

Insulin resistance, androgens, and lipids are gradually improved in an age-dependent manner in lean PCOS women. We hypothesize that if these women do not gain weight with the passage of time, there is a high probability that their cardiometabolic risk will be attenuated.

Homocysteine thiolactone-induced seizures in adult rats are aggravated by inhibition of inducible nitric oxide synthase

Homocysteine and its metabolites (homocysteine thiolactone (HT)) induce seizures via different but still not well-known mechanisms. The role of nitric oxide (NO) in epileptogenesis is highly contradictory and depends on, among other factors, the source of NO production. The aim of the present study was to examine the effects of aminoguanidine, selective inhibitor of inducible NO synthase (iNOS), on HT-induced seizures. Aminoguanidine (50, 75, and 100 mg/kg, intraperitoneally (i.p.)) was injected to rats 30 min prior to inducing HT (5.5 mmol/kg, i.p.). Seizure behavior was assessed by seizure incidence, latency time to first seizure onset, number of seizure episodes, and their severity during observational period of 90 min. Number and duration of spike and wave discharges (SWDs) were determined in electroencephalogram (EEG). Seizure latency time was significantly shortened, while seizure incidence, number, and duration of HT-induced SWD in EEG significantly increased in rats receiving aminoguanidine 100 mg/kg before subconvulsive dose of HT. Aminoguanidine in a dose-dependent manner also significantly increased the number of seizure episodes induced by HT and their severity. It could be concluded that iNOS inhibitor (aminoguanidine) markedly aggravates behavioral and EEG manifestations of HT-induced seizures in rats, showing functional involvement of iNOS in homocysteine convulsive mechanisms.

ENDOCRINE DISRUPTING CHEMICALS AND OBESITY: THE EVOLVING STORY OF OBESOGENS

Increase in obesity pandemic all over the world consequently leads to the investigation of possible causes. In addition to the traditional explanation using the so-called caloric model, the field of endocrine disruptors (EDs), especially subgroup called obesogens, offered more light on the pathogenetic mechanisms involved. After the Second World War a correlation between an increased production of exogenous pollutants and actual obesity epidemic was suggested. "Obesogen hypothesis" implies that molecules called obesogens inadequately stimulate the development of adipose cells and lipid accumulation in existing adipose cells, as well as change metabolic balance or hormonal control of appetite and satiety, leading to an increase in body fat mass. The list of obesogens includes some industrial chemicals, biocides, pharmaceuticals, pollutants, and smoke. EDs from the group of obesogens may exert their effects by the impairment in the programming development of adipocytes, by an increase in energetic depot in the adipose tissue, and by influencing neuroendocrine control of appetite and satiety. Increased scientific evidence on obesogens and their mechanisms of action may help to prevent obesity and mitigate deleterious effects of the environment on human life and development. New translational studies are needed to explain the possible mechanism proposed.

Preserved growth hormone (GH) secretion in aged and very old subjects after testing with the combined stimulus GH-releasing hormone plus GH-releasing hexapeptide-6

Either spontaneous or pharmacological stimulated GH secretion is reduced with advanced age. This observation is an added difficulty for the biochemical diagnosis of GH deficiency in adults. Furthermore, the combined administration of saturating doses of GH-releasing hormone (GHRH) plus GH-releasing hexapeptide (GHRP)-6 is nowadays the most effective GH-releasing stimulus tested in a variety of settings related to altered somatotroph function. To understand whether the GH discharge elicited by the combined stimulus declines with age, 26 normal subjects of both sexes, divided into 3 age groups [adults 19-40 yr; aged 46-65 yr; and very old (75-96 yr) subjects] were studied. They were administered i.v., as bolus and in combination, 90 micrograms GHRH plus 90 micrograms GHRP-6. In the three groups, the combined administration of GHRH plus GHRP-6 elicited a GH area under the curve (microgram/L per 120 min) of 3,127 +/- 262, 3,409 +/- 573, and 4,655 +/- 737 for adults, aged, and very old subjects, respectively (nonsignificant differences). The mean GH peak was 47.5 +/- 4.5 micrograms/L for adults, 52.9 +/- 8.4 micrograms/L for aged subjects, and 76.0 +/- 11.7 for very old subjects (nonsignificant differences). Individually examined, there were no nonresponders to the combined stimulus, and all subjects (independently of age) showed a GH peak over 25 micrograms/L (the lowest peak was 27.3 micrograms/L, and the highest peak was 119.2 micrograms/L). In conclusion, the GHRH plus GHRP-6-induced GH release is well preserved in aged and very old subjects, which suggests that the GH secretory capability of the combined test is not reduced by age. This combined test may be useful for the diagnosis of GH-deficient states in adults.

THE EFFECT OF MYOINOSITOL AND METFORMIN ON CARDIOVASCULAR RISK FACTORS IN WOMEN WITH POLYCYSTIC OVARY SYNDROME: A RANDOMIZED CONTROLLED TRIAL

CONTEXT

Cardiovascular risk is increased in women with polycystic ovary syndrome (PCOS). Do insulin sensitizing agents such as metformin (MET) and myoinositol (MI) ameliorate biomarkers of cardiovascular risk?

OBJECTIVE

To compare the effects of MET and MI on blood pressure, lipid profile and high sensitive C-reactive protein (hs-CRP) in women with PCOS in respect to their body mass index (BMI).

DESIGN

Open label, parallel randomized, single center study.

SUBJECTS AND METHODS

Sixty six women with PCOS (33 normal-weight and 33 overweight/obese) were randomized to either MI (4 g/day) or MET (1500 mg/day) for a period of 6 months. Serum concentration of hormones, lipid profile, oxidized LDL (ox-LDL), hs-CRP, blood pressure measurement and clinical assessment of BMI, waist circumference (WC) and Ferriman Gallwey score (FG score) were performed before and after treatment.

RESULTS

Thirty patients in each group completed the trial. Compared with MET, MI significantly decreased diastolic blood pressure (DBP) (p=0.036) and significantly increased serum hs-CRP (p=0.043). No differences between groups in total cholesterol (TC), HDL-cholesterol, LDL-cholesterol, ox-LDL and triglycerides were reported after 6 months. Treatment with MI reduced BMI (p=0.037), WC (p=0.005), DBP (p=0.021) and TC (p=0.008). During MET treatment a significant decrease in BMI (p=0.005), WC (p=0.004), FG score (p=0.001), testosterone (p=0.013) and free androgen index (FAI) (p=0.006) was observed.

CONCLUSIONS

Our study showed an advantage of MI in reduction of DBP and TC thus predicting favorable metabolic and cardiovascular outcomes in PCOS women. MET more effectively decrease indices of hyperandrogenism.

[Leptin and human reproduction]

Leptin is a secretory product of adipocytes. It has been suggested that leptin acts as an afferent satiety signal to the brain modulating the expression of the orexigenic hypothalamic peptide, neuropeptide Y (NPY). Therefore leptin can be regarded as a marker of the nutritional status of the body. It was proposed that human obesity may result from a central resistance to leptin due to different pathophysiological mechanisms: saturation of the leptin transport into the cerebrospinal fluid of the obese subjects, abnormalities in the hypothalamic receptor for leptin, or post-receptor transduction mechanisms. It was shown that circulating leptin levels in humans significantly correlate with the body mass index (BMI). Although most studies point to white adipose tissue as a primary source of leptin there is still some uncertainty towards the relative expression of leptin between various body fat compartments. LEPTIN AND ONSET OF PUBERTY: Studies on animal models recognized various metabolic candidates for modulation of GnRH neuronal activity. It was supposed that mild changes in the body's metabolic status can serve to regulate the central drive to the reproductive axis. It is likely that leptin can serve as a "metabolic cue" that transmits signals of those mild metabolic changes towards activation of the GnRH neuronal system at the end of the prepubertal period. On the other side there is a possibility of altered leptin pulsatility during prepubertal period that can consequently influence hypothalamus and GnRH neuronal system. LEPTIN AND SEXUAL DIMORPHISM: Leptin levels in humans are similar in both sexes during the prepubertal period. During puberty leptin has a tendency to decline in boys and to remain constant in girls. Puberty is also characterized with a similar circadian rhythm pattern between sexes whil girls express different pulse characteristics. It seems that sexual dimorphism is established in early phases of human development. There is a possibility of sex steroid influence on such sexual dimorphism. LEPTIN AND REPRODUCTIVE FUNCTION: It was shown that administration of recombinant leptin to ob ob mice could restore fertility in these infertile animals. There is certain difference in leptin levels according to the phase of the menstrual cycle. It was shown that leptin peak is in the luteal phase of the cycle and that correlates to the maximal progesterone level. It is possible that leptin could directly influence ovary and that disruption of such an effect could play a role in menstrual irregularities in both obese and mal nourished women. This could even become a pathophysiological mechanism in women with polycystic ovary syndrome (PCOS). It was supposed that leptin resistance could be involved in infertility impairment of the obese women with PCOS. Leptin increases during pregnancy. Appearance of placenta as a new, nonadipose source of leptin production, increases a possibility of different leptin mRNA expression through gestation.

OBESITY AND GUT-BRAIN AXIS

Epidemic of obesity is ongoing and did not slow down. Causes of obesity are numerous and very complex. Among them, the concept of bidirectional signaling within the brain-gut-microbiome axis was recently proposed as possible pathophysiological mechanism and become a hot topic in the explanations for the control of food intake. Discoveries of new anti-obesity drugs that are analogs for the receptors for some hormones derived from gastrointestinal tract contribute to the investigations in this area. The human gut microbiota plays a fundamental role in human health and disease and it is considered that it represent an endocrine organ that participate in energy homeostasis and host immunity. Role of gut microbiome has been investigated in metabolic diseases such as obesity, type 2 diabetes and non-alcoholic fatty liver disease. Gut microbiome participate in regulation of various mechanisms inside the gastrointestinal tract due to its production of different bacterial metabolites. In our manuscript we present current knowledge about microbiota in the gut; the relation between gut microbiota and brain; neuroendocrine system and gut-brain axis; immune system and gut-brain axis; endocrine system and gut-brain axis; the role of gut microbiota in obesity development and possible use of gut microbiota for the treatment of obesity.