Acute effects of concentric and eccentric exercise on glucose metabolism and interleukin-6 concentration in healthy males.

Acute muscle-damaging eccentric exercise (EE) negatively affects glucose metabolism. On the other hand, long-term eccentric endurance exercise seems to result in equal or superior positive effects on glucose metabolism compared to concentric endurance exercise. However, it is not known if acute non-muscle-damaging EE will have the same positive effects on glucose metabolism as acute concentric exercise (CE). Interleukin-6 (IL-6) released from the exercising muscles may be involved in the acute adaptations of glucose metabolism after CE and non-muscle-damaging EE. The aim of this study was to assess acute effects of uphill walking (CE) and non-muscle-damaging downhill walking (EE) on glucose metabolism and IL-6 secretion. Seven sedentary non-smoking, healthy males participated in a crossover trial consisting of a 1 h uphill (CE) and a 1 h downhill (EE) walking block on a treadmill. Venous blood samples were drawn before (pre), directly after (acute) and 24 h after (post) exercise. An oral glucose tolerance test (OGTT) was performed before and 24 h after exercise. Glucose tolerance after 1 and 2 hours significantly improved 24 hours after CE (-10.12±3.22%: P=0.039; -13.40±8.24%: P=0.028). After EE only the 1-hour value was improved (-5.03±5.48%: P=0.043). Acute IL-6 concentration rose significantly after CE but not after EE. We conclude that both a single bout of CE and a single bout of non-muscle-damaging EE elicit positive changes in glucose tolerance even in young, healthy subjects. Our experiment indicates that the overall metabolic cost is a major trigger for acute adaptations of glucose tolerance after exercise, but only the IL-6 production during EE was closely related to changes in glycaemic control.

Telomere length increase after weight loss induced by bariatric surgery: results from a 10 year prospective study.

BACKGROUND/OBJECTIVES: Obesity contributes to telomere attrition. Studies focusing on short-term effects of weight loss have been unable to identify protection of telomere length. This study investigates long-term effects of pronounced weight loss induced by bariatric surgery on telomere length. SUBJECTS/METHODS: One hundred forty-two patients were recruited in a prospective, controlled intervention study, follow-up investigations were done after 10.46±1.48 years. A control group of normal weight participants was recruited and followed from 1995 to 2005 in the Bruneck Study. A total of 110 participants from each study was matched by age and sex to compare changes in telomere length. Quantitative PCR was used to determine telomere length. RESULTS: Telomere length increased significantly by 0.024±0.14 (P=0.047) in 142 bariatric patients within 10 years after surgery. The increase was different from telomere attrition in an age- and sex-matched cohort population of the Bruneck Study (-0.057±0.18; ß=0.08; P=0.003). Significant changes in telomere length disappeared after adjusting for baseline body mass index (BMI) because of general differences in BMI and telomere length between the two study populations (ß=0.07; P=0.06). Age was proportional to telomere length in matched bariatric patients (r=0.188; P=0.049) but inversely correlated with telomere length in participants of the Bruneck Study (r=-0.197; P=0.039). There was no association between percent BMI/excess weight loss and telomere attrition in bariatric patients. Baseline telomere length in bariatric patients was inversely associated with baseline plasma cholesterol and triglyceride concentrations. Telomere shortening was associated with lower high-density lipoprotein cholesterol and higher fasting glucose concentration at baseline in bariatric patients. CONCLUSIONS: Increases in relative telomere length were found after bariatric surgery in the long term, presumably due to amelioration of metabolic traits. This may overrule the influence of age and baseline telomere length and facilitate telomere protection in patients experiencing pronounced weight loss.

Serum prolactin in advanced chronic liver disease.

Hyperprolactinemia is a frequent endocrine disorder with well known harmful effects on the reproductive system and bone metabolism. Besides prolactinomas several drugs and disorders such as renal failure and hypothyroidism have been shown to cause hyperprolactinemia. Based on former studies, liver cirrhosis has also been suggested to cause hyperprolactinemia, while mechanisms have not been identified yet. In this study, we set out to investigate the prevalence and predictors of hyperprolactinemia in 178 patients with liver cirrhosis of different etio-logies. Eighteen out of 178 patients - 7 females and 11 males - displayed elevated serum pro-lactin levels. When patients were excluded who suffered from co-morbidities or took medication that are discussed to potentially interfere with prolactin metabolism, only 3 males displayed increased serum prolactin levels. Prolactin levels were similar in patients with liver cirrhosis of different etiologies. Our data suggest that hyperprolactinemia is not commonly found in patients with liver cirrhosis, but is mostly associated with intake of drugs or presence of comorbidites which are known to potentially cause hyperprolactinemia. We thus hypothesize that in contrast to former studies liver cirrhosis is not a common cause of hyperprolactinemia and that in the absence of co-morbidities or drugs that are known to potentially increase prolactin levels, marked hyperprolactinemia needs further investigation in patients with liver cirrhosis.