Adiponectin as serum biomarker of insulin resistance in patients with polycystic ovarian syndrome

Exogenous APN protects normal tissues from radiation-induced oxidative damage and fibrosis in mice and prostate cancer patients with higher levels of APN have less radiation-induced toxicities

Radiation causes damage to normal tissues that leads to increased oxidative stress, inflammation, and fibrosis, highlighting the need for the selective radioprotection of healthy tissues without hindering radiotherapy effectiveness in cancer. This study shows that adiponectin, an adipokine secreted by adipocytes, protects normal tissues from radiation damage invitro and invivo. Specifically, adiponectin (APN) reduces chronic oxidative stress and fibrosis in irradiated mice. Importantly, APN also conferred no protection from radiation to prostate cancer cells. Adipose tissue is the primary source of circulating endogenous adiponectin. However, this study shows that adipose tissue is sensitive to radiation exposure exhibiting morphological changes and persistent oxidative damage. In addition, radiation results in a significant and chronic reduction in blood APN levels from adipose tissue in mice and human prostate cancer patients exposed to pelvic irradiation. APN levels negatively correlated with bowel toxicity and overall toxicities associated with radiotherapy in prostate cancer patients. Thus, protecting, or modulating APN signaling may improve outcomes for prostate cancer patients undergoing radiotherapy.

Markers of insulin resistance in Polycystic ovary syndrome women: An update

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, affecting 5%-10% of women of reproductive age. The importance of this syndrome lies in the magnitude of associated comorbidities: infertility, metabolic dysfunction, cardiovascular disease (CVD), plus psychological and oncological complications. Insulin resistance (IR) is a prominent feature of PCOS with a prevalence of 35%-80%. Without adequate management, IR with compensatory hyperinsulinemia contributes directly to reproductive dysfunction in women with PCOS. Furthermore, epidemiological data shows compelling evidence that PCOS is associated with an increased risk of impaired glucose tolerance, gestational diabetes mellitus and type 2 diabetes. In addition, metabolic dysfunction leads to a risk for CVD that increases with aging in women with PCOS. Indeed, the severity of IR in women with PCOS is associated with the amount of abdominal obesity, even in lean women with PCOS. Given these drastic implications, it is important to diagnose and treat insulin resistance as early as possible. Many markers have been proposed. However, quantitative assessment of IR in clinical practice remains a major challenge. The gold standard method for assessing insulin sensitivity is the hyperinsulinemic euglycemic glucose clamp. However, it is not used routinely because of the complexity of its procedure. Consequently, there has been an urgent need for surrogate markers of IR that are more applicable in large population-based epidemiological investigations. Despite this, many of them are either difficult to apply in routine clinical practice or useless for women with PCOS. Considering this difficulty, there is still a need for an accurate marker for easy, early detection and assessment of IR in women with PCOS. This review highlights markers of IR already used in women with PCOS, including new markers recently reported in literature, and it establishes a new classification for these markers.

A Systematic Review of the Effects of Exercise on Hormones in Women with Polycystic Ovary Syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that is characterized by menstrual irregularity and elevated serum androgens, and is often accompanied by insulin resistance. The etiology of PCOS is unknown. Lifestyle interventions and weight loss, where appropriate, remain first-line treatments for women with PCOS. Regular physical activity is recommended for women with PCOS to maintain a healthy weight and cardiovascular fitness.

PURPOSE

To review the evidence for the impact of various exercise interventions on hormone levels in women with PCOS.

METHODS

A systematic review of original studies indexed in PubMed that utilized an exercise intervention in women with PCOS and reported hormone values pre- and post-intervention. Studies in which the effects of the exercise intervention could be determined were included.

RESULTS

Vigorous aerobic exercise improves insulin measures in women with PCOS. Resistance or strength training may improve androgen levels, though additional studies are warranted. Studies with yoga are limited but suggest improvements in androgens. Limited information is available on the impact of exercise on adipokines and anti-Müllerian hormone, warranting further investigation.

CONCLUSIONS

Recommended guidelines for women with PCOS include vigorous aerobic exercise and resistance training to improve measures of insulin sensitivity and androgen levels.

Adiponectin and leptin levels in normal weight women with polycystic ovary syndrome

Objectives

Since polycystic ovarian syndrome (PCOS) is prevalent in reproductive women with obesity and insulin resistance, adipocytokines are often accused and investigated for pathophysiology. The aim of this study was to evaluate the adiponectin and leptin levels in normal-weight women with PCOS.

Methods

Forty women with PCOS and 40 age and body mass index (BMI) matched controls were included in the study. Adiponectin and leptin levels in addition to other biochemical parameters were measured.

Results

Leptin levels were statistically significantly higher in the study group compared to the control group (6.53 ± 2.670 vs 3.37 ± 2.002 ng/mL, p < 0.001 respectively). Although Adiponectin levels were lower in the study group compared to the control group (28.89 ± 16.124 μg/mL vs 31.05 ± 20.507, p = 0.714 respectively) the difference did not reach statistical significance. Leptin levels were positively correlated with fasting glucose, fasting insulin, free testosterone levels and homeostatic model assessment of insulin resistance (HOMA-IR) values. Adiponectin levels were negatively correlated with BMI.

Conclusions

Adiponectin and leptin have been suggested to play a crucial role in the pathogenesis of PCOS. Different adipocytokine levels in the normal weight PCOS group compared to age and BMI matched controls support the idea that adipose tissue in this group of women has some distinctive features not only in high BMI subgroup but also in normal weight subgroup.

A pilot trial of metformin for insulin resistance and mood disturbances in adolescent and adult women with polycystic ovary syndrome

We examine the effects of metformin on insulin resistance (IR) and mood including in adolescent and adult women with polycystic ovary syndrome (PCOS). This trial was conducted in 19 adolescents (age ≤18 years) and 25 adult (age >18 years) women with PCOS. Anthropometric and measurements including, serum glucose, endocrine panel, and lipid profile were performed at baseline. IR was measured by Homeostasis Model Assessment IR (HOMA-IR). Anxiety and depression were measured by Beck's Anxiety (BAI) and Depression Inventories (BDI-II). All tests were repeated after a 90-day treatment with metformin (1,500 mg/day). The severity of depression and anxiety decreased after 90-day treatment with metformin in women diagnosed with PCOS. The BAI scores were higher in adolescent group while BDI-II scores were higher in the adult group (p = .016). After 90-day metformin treatment, both BDI-II and BAI scores were decreased by 3.3 and 3.4, respectively (p < .001). Indicators of IR and obesity were improved with this therapy. Although the adolescents weighed lower than the adults, baseline HOMA-IR 5.5 ± 1.7 was higher in this group than 4.4 ± 1.2 in the adult women (p =.022). The findings suggest that metformin decrease IR and improve mood both in adolescent and adult women with PCOS.

Role of Serum Adiponectin and Vitamin D in Prediabetes and Diabetes Mellitus

OBJECTIVES

The roles of deficient or deranged insulin, adiponectin and 25 hydroxy vitamin D (25[OH]D) levels regulating food intake, energy metabolism, glucose and lipid metabolism and body weight have been reported in the pathogenesis of prediabetes and type 2 diabetes mellitus. However, their congruity in the etiology of diabetes mellitus is unknown. Thus, the aim of the study was to investigate the roles of these parameters together and to establish their interrelationship in patients with prediabetes and diabetes.

METHODS

The preliminary cross-sectional study included 77 persons with type 2 diabetes who were matched for age, sex and body mass index (BMI); 73 persons with prediabetes; and 52 healthy control subjects. Fasting serum levels of adiponectin, insulin and 25(OH)D were measured by commercially available immune assay kits, and routine biochemical parameters were analyzed in all study groups.

RESULTS

The results show statistically significant lower levels of serum adiponectin and serum 25(OH)D and higher serum insulin levels in persons with prediabetes or type 2 diabetes with respect to controls. The changes in the serum adiponectin or serum 25(OH)D in persons with prediabetes and type 2 diabetes were found to be inversely correlated with the serum levels of insulin. Moreover, multiple linear regression analysis, with 25(OH)D, insulin and homeostatic model assessment-insulin resistance (HOMA-IR) as the variables, revealed that serum adiponectin levels might be an independent risk factor for the progression of prediabetes and type 2 diabetes in subjects.

CONCLUSIONS

The association of these hormones might act as a significant predictor of progression of prediabetes to type 2 diabetes. Decreased serum adiponectin levels might be an independent risk factor for progression to prediabetes and type 2 diabetes, which may help in developing experimental models of the disease or in identifying biomarkers or disease-modifying drugs.