Leptin level and oxidative stress contribute to obesity-induced low testosterone in murine testicular tissue

Objective. This study evaluated the effects of obesity on the function of reproductive organs in male mice and the possible mechanism of male secondary hypogonadism (SH) in obesity. Methods. Ninety-six mice were randomly assigned to three groups: the control group, diet-induced obesity group, and diet-induced obesity resistant group for 8 weeks and 19 weeks. The effects of short- and long-term high-fat diet on the reproductive organs were determined by measuring sperm count and motility, relative testis weight, testosterone level, pathological changes and apoptosis of Leydig cells. Oxidative stress was evaluated by determining malondialdehyde, H₂O₂, NO levels, and GSH in testis tissues. CAT, SOD, GSH-Px and Nrf₂ mRNA were measured by real-time PCR. Results. Short- and long-term high-fat diet decreased sperm count and motility, relative testis weight, testosterone level; decreased CAT, SOD, GSH-Px and Nrf₂ mRNA expression; increased MDA, H₂O₂, NO and leptin levels; inhibited the activity of CAT and GSH-Px enzymes. Pathological injury and apoptosis of Leydig cells were found in testis tissue. Conclusions. Pathological damage of Leydig cells, oxidative stress in testis tissue, and high level of leptin may provide some evidence to clarify the mechanisms of male SH in obesity.

Abdominal obesity and serum adiponectin complexes among population-based elementary school children in Japan: a cross-sectional study

Background

There are a limited number of studies regarding the association between abdominal obesity and serum adiponectin complexes (high, medium, and low molecular weight adiponectins) among population-based elementary school children, especially in Japan, where blood collection is not usually performed during annual health examinations of school children. The aim of the present study was to investigate the relationship between abdominal obesity and serum adiponectin complexes among population-based elementary school children in Japan.

Methods

Subjects were all the fourth-grade school children (9 or 10 years of age) in the town of Ina during 2005–2008 (N = 1675). The height, weight, percent body fat, and waist circumference (WC) of each subject were measured. Blood samples were drawn from subjects to measure adiponectin isoform values. Childhood abdominal obesity was defined as “a waist-to-height ratio greater than or equal to 0.5” or “a WC greater than or equal to 75 cm”. The Wilcoxon rank-sum test and the logistic regression model were used to analyze the association between abdominal obesity and each adiponectin isoform value.

Results

Data from 1654 subjects (846 boys and 808 girls) were analyzed. Adiponectin complexes were lower in the abdominal obesity group than in the non-abdominal obesity group regardless of sex. Abdominal obesity significantly increased the odds ratio (OR) for each adiponectin isoform level less than or equal to the median value in boys; the OR (95% confidence interval [CI]) was 2.50 (1.59-3.92) for high molecular weight adiponectin (HMW-adn), 2.47 (1.57-3.88) for medium molecular weight adiponectin (MMW-adn), and 1.75 (1.13-2.70) for low molecular weight adiponectin (LMW-adn). In girls, the OR (95% CI) was 1.95 (1.18-3.21) for HMW-adn, 1.40 (0.86-2.28) for MMW-adn, and 1.06 (0.65-1.70) for LMW-adn.

Conclusions

Abdominal obesity was associated with lower adiponectin complexes and the influence of abdominal obesity varied by adiponectin isoform. Furthermore, the impact of abdominal obesity was larger in boys than in girls. The present study results suggest that prevention of abdominal obesity could contribute to the prevention of lower adiponectin levels, especially in boys.

Long-term testosterone therapy in hypogonadal men ameliorates elements of the metabolic syndrome: an observational, long-term registry study

AIM

The goal of this study was to determine if long-term testosterone (T) therapy in men with hypogonadism, henceforth referred to as testosterone deficiency (TD), ameliorates or improves metabolic syndrome (MetS) components.

METHODS

We performed a cumulative registry study of 255 men, aged between 33 and 69 years (mean 58.02 ± 6.30) with subnormal plasma total T levels (mean: 9.93 ± 1.38; range: 5.89-12.13 nmol/l) as well as at least mild symptoms of TD assessed by the Aging Males' symptoms scale. All men received treatment with parenteral T undecanoate 1000 mg (Nebido(®) , Bayer Pharma, Berlin, Germany), administered at baseline and 6 weeks and thereafter every 12 weeks for up to 60 months. Lipids, glucose, liver enzymes and haemoglobin A1c analyses were carried out in a commercial laboratory. Anthropometric measurements were also made throughout the study period.

RESULTS

Testosterone therapy restored physiological T levels and resulted in reductions in total cholesterol (TC) [7.29 ± 1.03 to 4.87 ± 0.29 mmol/l (281.58 ± 39.8 to 188.12 ± 11.31 mg/dl)], low-density lipoprotein cholesterol [4.24 ± 1.07 to 2.84 ± 0.92 mmol/l (163.79 ± 41.44 to 109.84 ± 35.41 mg/dl)], triglycerides [3.14 ± 0.58 to 2.16 ± 0.13 mmol/l (276.16 ± 51.32 to 189.78 ± 11.33 mg/dl)] and increased high-density lipoprotein levels [1.45 ± 0.46 to 1.52 ± 0.45 mmol/l (56.17 ± 17.79 to 58.85 ± 17.51 mg/dl)] (p < 0.0001 for all). There were marked reductions in systolic and diastolic blood pressure, blood glucose, haemoglobin A1c , C-reactive protein (6.29 ± 7.96 to 1.03 ± 1.87 U/l), alanine aminotransferase and aspartate aminotransferase (p < 0.0001 for all).

CONCLUSIONS

Long-term T therapy, at physiological levels, ameliorates MetS components. These findings strongly suggest that T therapy in hypogonadal men may prove useful in reducing the risk of cardiometabolic diseases.

Metabolic adaptation to weight loss: implications for the athlete

Optimized body composition provides a competitive advantage in a variety of sports. Weight reduction is common among athletes aiming to improve their strength-to-mass ratio, locomotive efficiency, or aesthetic appearance. Energy restriction is accompanied by changes in circulating hormones, mitochondrial efficiency, and energy expenditure that serve to minimize the energy deficit, attenuate weight loss, and promote weight regain. The current article reviews the metabolic adaptations observed with weight reduction and provides recommendations for successful weight reduction and long term reduced-weight maintenance in athletes.

Endocrine regulation of bone and energy metabolism in hibernating mammals

Precise coordination among organs is required to maintain homeostasis throughout hibernation. This is particularly true in balancing bone remodeling processes (bone formation and resorption) in hibernators experiencing nutritional deprivation and extreme physical inactivity, two factors normally leading to pronounced bone loss in non-hibernating mammals. In recent years, important relationships between bone, fat, reproductive, and brain tissues have come to light. These systems share interconnected regulatory mechanisms of energy metabolism that potentially protect the skeleton during hibernation. This review focuses on the endocrine and neuroendocrine regulation of bone/fat/energy metabolism in hibernators. Hibernators appear to have unique mechanisms that protect musculoskeletal tissues while catabolizing their abundant stores of fat. Furthermore, the bone remodeling processes that normally cause disuse-induced bone loss in non-hibernators are compared to bone remodeling processes in hibernators, and possible adaptations of the bone signaling pathways that protect the skeleton during hibernation are discussed. Understanding the biological mechanisms that allow hibernators to survive the prolonged disuse and fasting associated with extreme environmental challenges will provide critical information regarding the limit of convergence in mammalian systems and of skeletal plasticity, and may contribute valuable insight into the etiology and treatment of human diseases.

Long-term treatment of hypogonadal men with testosterone produces substantial and sustained weight loss

OBJECTIVE

This study analyzed the effects of normalization of serum testosterone (T) levels on anthropometric parameters in hypogonadal men.

DESIGN AND METHODS

Open-label, single-center, cumulative, prospective registry study of 255 men (aged 33-69 years, mean 58.02 ± 6.30 years), with T levels below 12.13 nmol/L (mean: 9.93±1.38). 215 men for at least 2 years, 182 for 3 years, 148 for 4, and 116 for at least 5 years were studied. They received parenteral T undecanoate 1,000 mg/12 weeks after an initial interval of 6 weeks.

RESULTS

Body weight (BW) decreased from 106.22 ± 16.93 kg to 90.07 ± 9.51 kg. Waist circumference (WC) reduced from 107.24 ± 9.14 cm to 98.46 ± 7.39 cm. BMI (m/kg(2) ) declined from 33.9 ± 5.51 m/kg(2) to 29.13 ± 3.09 m/kg(2) . All parameters examined were statistically significant with P < 0.0001 versus baseline and versus the previous year over 5 years indicating a continuous weight loss over the full observation period. The mean per cent weight loss after 1 year was 4.16 ± 0.31%, after 2 years 7.54 ± 0.32%, after 3 years 9.23 ± 0.33%, after 4 years 11.42 ± 0.35% and after 5 years 13.57 ± 0.37%.

CONCLUSIONS

In an uncontrolled, observational cohort, normalizing serum T to normal physiological levels produced consistent loss of BW, WC, and BMI. These improvements were progressive over the full 5 years of the study.

How to approach endocrine assessment in severe obesity?

The increasing numbers of severely obese patients (body mass index BMI >40 kg/m(2) ) represent a significant management challenge. These patients are at risk of obesity-related complications that may be driven by changes in endocrine function. Their care may potentially be complex at times, and therefore, an appropriate assessment strategy will be relevant to timely diagnosis and management. In this article, we discuss an approach to the endocrine assessment of the severely obese patient. We consider the clinical question in three categories that may also represent different complexities in terms of subsequent management: (i) obesity as a consequence of structural lesions at the hypothalamic-pituitary region; (ii) obesity as a consequence of inherited and genetic syndromes; and (iii) functional neuroendocrine hormone abnormalities relating to obesity. The first two categories are associated with hypothalamic dysfunction, of which hypothalamic obesity is a consequence. Additionally, the implications and difficulties associated with imaging severely obese patients are discussed from an endocrinological perspective and we provide practical guidance on which to base practice.

Synthesis of esters of androgens with unsaturated fatty acids for androgen requiring therapy

Androgens' metabolism and activity are gaining a more and more important role in human physiology particularly referring to aging and to neurodegenerative diseases. Androgen treatment is often required for long-lasting disorders. In order to improve their duration and effects, androgens can be administered as esters of carboxylic acids. The novelty of our research is the use of esters of androgens with specific unsaturated fatty acids, in order to reduce possible side effects particularly related to chronic pathologies with altered lipid homeostasis such as X-linked adrenoleukodystrophy and cardiovascular disorders. Thus the esters of the main androgenic substances testosterone, dihydrotestosterone (DHT) and their metabolite 5α-androstan-3α,17β-diol were chemically obtained by coupling with different unsaturated fatty acids. To this aim, fatty acids with various degree of unsaturation and belonging to different series were selected. Specifically, oleic acid (18:1, n-9), linoleic acid (18:2, n-6), and the n-3 fatty acids, α-linolenic acid (18:3), eicosapentaenoic acid (EPA, 20:5), and docosahexaenoic acid (DHA, 22:6) were used obtaining corresponding esters with acceptable yields and good degree of purity. All the synthesized compounds were tested for their cytotoxic activities in mouse NIH3T3 and human astrocyte cell lines. The esters demonstrated good tolerability and no in vitro cytotoxic effect in both cell cultures. After these promising preliminary results, the esters will be suitable for in vivo studies in order to ascertain their pharmacokinetic characteristics and their biological effects.

Low total testosterone levels are associated with the metabolic syndrome in elderly men: the role of body weight, lipids, insulin resistance, and inflammation; the Ikaria study

BACKGROUND

The prevalence of the metabolic syndrome (MetS) increases with age. Among other changes, testosterone levels decline with age. The relationship between testosterone levels and MetS components in older subjects has not been clearly defined until today.

OBJECTIVES

The aim of this work was to evaluate the relationship between total serum testosterone levels and MetS and its components.

METHODS

The working sample consisted of 467 elderly individuals (mean age 75 ± 6 years old, n = 220 men) from Ikaria Island, Greece. MetS was defined according to the NCEP ATPIII criteria.

RESULTS

MetS prevalence was 52% in men and 64% in women. Those with MetS had lower testosterone levels; a 10 ng/dl increase in testosterone was associated with a 3% reduction in odds of having MetS in men (95% CI: 0.95-0.99), but not in women. This remained the result after various adjustments had been made, including daily hours of sleep. Testosterone was inversely associated with abnormal waist circumference, high-sensitivity C-reactive protein (hs-CRP), insulin, and HDL cholesterol levels in men only. When lipid categories, hs-CRP, BMI, and insulin resistance levels were taken into account, testosterone lost its significance in predicting MetS (p < 0.20), suggesting that these markers possess a mediating effect.

CONCLUSIONS

In elderly men, low serum testosterone was associated with MetS. Lipids, BMI, inflammation, and insulin resistance levels seem to explain this relationship, suggesting a potential mediating effect. This finding may support a research hypothesis relating serum testosterone to cardiovascular disease, which requires further research.