Leukocyte telomere length is associated with elevated plasma glucose and HbA1c in young healthy men independent of birth weight.

Telomeres are protein-bound regions of repetitive nucleotide sequences (TTAGGG) at the end of human chromosomes, and their length is a marker of cellular aging. Intrauterine growth restriction is associated with shorter blood cell telomeres at birth and individuals with type 2 diabetes have shorter telomeres. Individuals with a low birth weight (LBW) have an increased risk of metabolic disease and type 2 diabetes. Therefore, we aimed to investigate the relationship between birth weight and telomere length and the association between birth weight, telomere length and cardiometabolic phenotype in adulthood. Young, healthy men with LBW (n = 55) and normal birth weight (NBW) (n = 65) were examined including blood pressure, blood samples and body composition. Leukocyte telomere length was determined using a high-throughput qPCR method. The LBW men were more insulin resistant as determined by the HOMA-IR index. There was no difference in telomere length between LBW and NBW subjects. When adjusting for birth weight and cohort effect, significant negative associations between telomere length and fasting glucose (P = 0.003) and HbA1c (P = 0.0008) were found. In conclusion, no significant difference in telomere length was found between LBW and NBW men. The telomere length was negatively associated with glucose concentrations and HbA1c levels within the normal non-diabetic range independent of birth weight.

Mast Cells Might Have a Protective Role against the Development of Calcification and Hyalinisation in Severe Aortic Valve Stenosis.

Aortic valve stenosis is characterized by inflammation and extracellular matrix remodelling. The aim of this study was to analyse the impact of mast cells on the occurrence of histopathological changes of aortic valves in patients with severe grade, non-rheumatic degenerative aortic valve stenosis. Valve specimens were obtained from 38 patients undergoing valve replacement. The role of mast cells was analysed by dividing the specimens into two groups, characterized by the presence (group A, N = 13) or absence of mast cells (group B, N = 25). There were no significant differences in clinical data between the two groups. In group A, T cells and macrophages were present in all aortic valves, as compared to a significantly lower proportion of valves with T cells and macrophages in group B. Valves in group A were less often calcified and hyaline-degenerated than valves in group B. There were no changes in fibrosis between the two groups. We found a positive correlation between the presence of mast cells and macrophages/T cells, a negative correlation between the presence of mast cells and calcification/ hyaline degeneration, and no correlation between the presence of mast cells and fibrosis. There was also a negative correlation between the presence of macrophages/T cells and calcification. The linear regression model identified only the presence of mast cells as an independent negative prediction value for calcification. In conclusion, mast cells might have a protective role against the development of calcification and hyaline degeneration in severe grade, non-rheumatic aortic valve stenosis.

Insulin resistance induced by physical inactivity is associated with multiple transcriptional changes in skeletal muscle in young men.

Physical inactivity is a risk factor for insulin resistance. We examined the effect of 9 days of bed rest on basal and insulin-stimulated expression of genes potentially involved in insulin action by applying hypothesis-generating microarray in parallel with candidate gene real-time PCR approaches in 20 healthy young men. Furthermore, we investigated whether bed rest affected DNA methylation in the promoter region of the peroxisome proliferator-activated receptor-γ coactivator-1α (PPARGC1A) gene. Subjects were reexamined after 4 wk of retraining. We found that bed rest induced insulin resistance and altered the expression of more than 4,500 genes. These changes were only partly normalized after 4 wk of retraining. Pathway analyses revealed significant downregulation of 34 pathways, predominantly those of genes associated with mitochondrial function, including PPARGC1A. Despite induction of insulin resistance, bed rest resulted in a paradoxically increased response to acute insulin stimulation in the general expression of genes, particularly those involved in inflammation and endoplasmatic reticulum (ER) stress. Furthermore, bed rest changed gene expressions of several insulin resistance and diabetes candidate genes. We also observed a trend toward increased PPARGC1A DNA methylation after bed rest. We conclude that impaired expression of PPARGC1A and other genes involved in mitochondrial function as well as a paradoxically increased response to insulin of genes involved in inflammation and ER stress may contribute to the development of insulin resistance induced by bed rest. Lack of complete normalization of changes after 4 wk of retraining underscores the importance of maintaining a minimum of daily physical activity.

The disposition index: adjustment for peripheral vs. hepatic insulin sensitivity?

The assessment of pancreatic beta cell function in humans is challenging because of a complex interplay between insulin secretion, insulin sensitivity and hepatic insulin extraction. Simplified, the relationship between insulin secretion and insulin sensitivity can be described by an approximate hyperbola with the product of the two variables being constant for individuals with the same degree of glucose tolerance (the disposition index). Strengths and limitations of the disposition index have been widely debated in the literature. In this review we will focus on another and until recently unrecognized dimension of the disposition index, namely the issue of adjusting insulin secretion for hepatic versus peripheral insulin sensitivity. An underlying assumption of this issue is that the liver as compared to muscle plays a different role in the regulation of in vivo insulin secretion.

Increased rate of whole body lipolysis before and after 9 days of bed rest in healthy young men born with low birth weight.

Individuals born with low birth weight (LBW) are at risk of developing type 2 diabetes mellitus (T2D), which may be precipitated by physical inactivity. Twenty-two LBW subjects and twenty-three controls were studied before and after bed rest by the hyperinsulinemic euglycemic clamp combined with indirect calorimetry and infusion of stable isotope tracers and preceded by an intravenous glucose tolerance test. LBW subjects had a similar body mass index but elevated abdominal obesity compared with controls. The basal rate of whole body lipolysis (WBL) was elevated in LBW subjects with and without correction for abdominal obesity before and after bed rest (all P = 0.01). Skeletal muscle hormone-sensitive lipase (HSL) protein expression and phosphorylation at Ser565 were similar in the two groups. Bed rest resulted in a decrease in WBL and an increased skeletal muscle HSL Ser565 phosphorylation indicating a decreased HSL activity in both groups. All subjects developed peripheral insulin resistance in response to bed rest (all P < 0.0001) with no differences between groups. LBW subjects developed hepatic insulin resistance in response to bed rest. In conclusion, increased WBL may contribute to the development of hepatic insulin resistance when exposed to bed rest in LBW subjects. Nine days of bed rest causes severe peripheral insulin resistance and reduced WBL and skeletal muscle HSL activity, as well as a compensatory increased insulin secretion, with no differences in LBW subjects and controls.

Diminished insulin-mediated forearm blood flow and muscle glucose uptake in young men with low birth weight.

BACKGROUND: Low birth weight (LBW) is associated with increased risk of type 2 diabetes and cardiovascular disease. We studied endothelial function and insulin sensitivity in young men with LBW (n = 22) and controls (n = 22). METHODS: Insulin sensitivity and endothelial function was studied with venous occlusion plethysmography and intra-arterial infusions of adenosine and acetylcholine, before and during a hyperinsulinemic isoglycemic clamp. RESULTS: Forearm blood flow response to systemic hyperinsulinemia was diminished in LBW compared to controls (p < 0.05). Fractional arteriovenous glucose extraction was similar, and consequently insulin-stimulated forearm glucose clearance was diminished in LBW compared with controls (0.8 +/- 0.09 vs. 1.4 +/- 0.36 ml x 100 ml(-1) x min(-1), respectively, p < 0.05). Forearm blood flow response to adenosine and acetylcholine with or without insulin stimulation did not differ between groups. Whole-body glucose uptake was lower in LBW than controls (8.7 +/- 0.5 and 9.1 +/- 0.6 mg x min(-1) x kg(-1) lean body mass); however, this was not significant. CONCLUSIONS: Forearm blood flow response to insulin is impaired in LBW, whereas the response to adenosine and acetylcholine is preserved. The impaired insulin-mediated increase in bulk flow in LBW may be due to an impairment of insulin-mediated capillary recruitment independent of - or preceding - whole-body insulin resistance in LBW subjects.

Effect of adjunct metformin treatment on levels of plasma lipids in patients with type 1 diabetes.

BACKGROUND: In addition to its glucose-lowering effect, metformin treatment has been suggested to improve lipidaemia in patients with type 2 diabetes. In contrast, in patients with type 1 diabetes (T1DM), information about the effect of metformin treatment on lipidaemia is limited. In this study, we report the effect of a 1-year treatment with metformin vs. placebo on plasma lipids in T1DM patients and persistent poor glycaemic control. METHODS: One hundred T1DM patients with haemoglobinA(1c) (HbA(1c)) > or =8.5% during the year before enrolment entered a 1-month run-in period on placebo treatment. Thereafter, patients were randomized (baseline) to treatment with either metformin (1000 mg twice daily) or placebo for 12 months (double masked). Patients continued ongoing insulin therapy and their usual outpatient clinical care. Outcomes were assessed at baseline and after 1 year. RESULTS: After 1 year, in those patients who did not start or stop statin therapy during the trial, metformin treatment significantly reduced total and LDL cholesterol by approximately 0.3 mmol/l compared with placebo (p = 0.021 and p = 0.018 respectively). Adjustment for statin use or known cardiovascular disease did not change conclusions. In statin users (metformin: n = 22, placebo: n = 13), metformin significantly lowered levels of LDL and non-HDL cholesterol by approximately 0.5 mmol/l compared with placebo (adjusted for changes in statin dose or agent: p = 0.048 and p = 0.033 respectively). HbA(1c) (previously reported) was not significant different between treatments. CONCLUSION: In patients with poorly controlled T1DM, at similar glycaemic levels, adjunct metformin therapy during 1 year significantly lowered levels of proatherogenic cholesterolaemia independent of statin therapy.

Apoptosis of cardiomyocytes in myocarditis.

Apoptosis of cardiomyocytes has been reported to be involved in the pathogenesis of heart failure of different aetiologies. The purpose of this study is to assess the role and extent of apoptosis of cardiomyocytes in active myocarditis. Endomyocardial samples from the right ventricle of 22 patients with active myocarditis were compared with 25 traffic accident victims without a history of cardiovascular disease. Twenty-two patients fulfilled the histopathologic Dallas criteria for myocarditis. The TUNEL method and immunostaining for active caspase 3 were used for the detection of apoptosis. Immunohistochemical methods were used for the evaluation of regulators of apoptosis (p53, Bcl-2) and evaluation of interstitial cells (macrophages, T and B lymphocytes). Apoptosis of cardiomyocytes (TUNEL-positive and anti-caspase 3-positive cardiomyocytes), which was not p53-dependent, was present in 0.3 to 0.4% (0.3% by TUNEL method and 0.4% by immunostaining for active caspase 3) of cardiomyocytes in active myocarditis, whereas only few apoptotic cardiomyocytes (0.0006 +/- 0.002% TUNEL-positive cardiomyocytes and 0.001 +/- 0.002% active caspase 3-positive cardiomyocytes) were found in the control group (P = 0.001). Apoptotic (TUNEL-positive and active caspase 3-positive) cardiomyocytes were found in small clusters. An increased expression of Bcl-2 was found in active myocarditis compared to the controls (P < 0.01), yet Bcl-2 failed to protect myocytes from apoptosis. We provide evidence of apoptosis of cardiomyocytes in active myocarditis, which may be involved in the development of heart failure.

Metabolic aspects of insulin resistance in individuals born small for gestational age.

Numerous studies have shown an association between low weight at birth and being born small for gestational age (SGA) on the one hand and risk of developing insulin resistance and type 2 diabetes on the other. Our studies in twins have indicated a non-genetic age-dependent origin of insulin resistance and type 2 diabetes associated with being born SGA. In order to gain insight into the molecular metabolic defects and mechanisms linking SGA with insulin resistance and type 2 diabetes, we performed a series of experiments in young and elderly twins, and, in particular, in young men (aged 19-23 years) with a weight at birth at term in the lowest 10th percentile with no family history of diabetes. The control group included age-matched men with birth weights at term in the upper normal range. While body mass index and waist-to-hip ratios were similar in the individuals born SGA and controls, dual-energy X-ray absorptiometry studies documented a higher degree of abdominal obesity in the men who had a low weight at birth. Using the gold standard hyperinsulinaemic-euglycaemic clamp technique combined with glucose tracers and studies of forearm glucose uptake, we found an impairment of insulin-stimulated glycolytic flux and reduced forearm (muscle) glucose uptake in the face of normal whole-body glucose uptake. In addition, we found a significantly decreased insulin secretion rate during oral glucose ingestion after correction for insulin action (disposition index), a paradoxical enhanced insulin suppression of hepatic glucose production and lower fasting plasma glycerol levels, suggesting impaired lipolysis. Finally, analysis of skeletal muscle biopsies showed reduced muscle expression of several key proteins involved in insulin signalling and glucose transport, including protein kinase C-zeta, the two subunits of phosphoinositol 3-kinase (i.e., p85alpha and p110beta) and the insulin-sensitive glucose transporter, Glut-4, in individuals of low birth weight. In conclusion, being born SGA and of low birth weight is associated with type 2 diabetes in a non-genetic manner, and programming of muscle insulin action and signalling represents an early mechanism responsible for this association.

Viability of human chondrocytes in an ex vivo model in relation to temperature and cartilage depth.

Chondrocytes in human articular cartilage remain viable post-mortem. It has however not been established yet how the storage temperature affects their survival, which is essential information when post-mortem cartilage is used for toxicologic studies. Our aim was to construct a simple model of explanted knee cartilage and to test the influences of time and temperature on the viability of chondrocytes in the ex vivo conditions. Osteochondral cylinders were procured from the cadaveric femoral condyles. The cylinders were embedded in water-tight rubber tubes, which formed separate chondral and osteal compartments. Tubes were filled with normal saline, without additives, to keep chondrocytes under close-to-normal conditions. The samples were divided into two groups stored at 4 degrees C and 35 degrees C, respectively. Three samples of each of these two groups were analysed at the time of removal, and then three and nine days later. Images of Live-Dead staining were scanned by a confocal laser microscope. Count of viable chondrocytes in four regions, from surface to bone, was obtained using image analysis software. The regression model revealed that the number of viable chondrocytes decreased every day by 19% and that an increase in temperature by 1 degree C decreased their viability by 5.8%. The temperature effect fell by 0.2 percentage points for every 100 microm from the surface to the bone. Herein we demonstrate that chondrocytes remain viable in the ex vivo model of human knee cartilage long enough to be able to serve as a model for toxicologic studies. Their viability is, however, significantly influenced by time and temperature.

Our experiences with fatal ecstasy abuse (two case reports).

Ecstasy is a psychostimulative drug (ab)used mostly by teenagers and young adults in discotheques and on the "rave" parties. Older adults ecstasy abusing cases are very rare. Among four cases of ecstasy abuse with fatal outcome noticed and examined in Slovenia, two were examined at our Institute of Forensic Medicine in Ljubljana. The first case was the accidental intoxication with 3,4 methylenedioxymethamphetamine (MDMA) on "rave" party, the second case was suicidal intoxication with combination of insulin and MDMA. Because of the increasing popularity of MDMA, it is important for all emergency physicians to be well educated in prompt recognition of MDMA intoxication symptoms. It is important that emergency physician carefully examines the death scene.

Hyperglycaemia and survival after haemorrhage.

OBJECTIVE: To assess the relation between the degree of hyperglycaemia during a standard haemorrhage and survival. DESIGN: Prospective laboratory study SETTING: University department of surgery, Sweden MATERIAL: 5 groups of 8-12 adult male Sprague-Dawley rats. INTERVENTIONS: Different degrees of hyperglycaemia were achieved in the 5 groups of rats (which had been starved for 24 hours) by infusion of the same amount of 0.9% saline, or 5%, 10%, 20% or 30% glucose during a 48% standard haemorrhage over 60 minutes. Blood glucose concentration and packed cell volume were measured every 30 minutes, and mean arterial pressure was monitored constantly. MAIN OUTCOME MEASURE: Survival at 7 days. RESULTS: Increases in blood glucose concentrations during haemorrhage correlated with plasma refill as indicated by reductions in packed cell volume (r = 0.85, p < 0.0001). Both increases in blood glucose concentrations and reductions in packed cell volume were inversely related to blood pressure during haemorrhage (p < 0.0001). The more glucose that was infused, the higher the blood glucose concentration and the better the plasma refill during haemorrhage which correlated with improvement in the rate of survival at 7 days (p < 0.001). CONCLUSION: The ability to mount a hyperglycaemic response is an important prognostic factor in survival after experimental haemorrhage.

Pretreatment with glucose infusion prevents fatal outcome after hemorrhage in food deprived rats.

Twenty-four hour food deprivation increases mortality after experimental hemorrhage. Survival after hemorrhage is closely related to the capacity of the animal to develop hyperglycemia. In this study, 24 hr food deprived rats were given a 3-hr infusion of either 0.3 ml/100 g b.wt./h 30% glucose iv (n = 10) or the same volume of 0.9% NaCl (n = 10) prior to 60 min of standardized hemorrhage. Glucose infusion resulted in a transient hyperglycemia, and 600% greater hepatic glycogen content compared to saline (P < 0.001). During hemorrhage, glucose-treated rats developed substantial hyperglycemia while glucose levels fell in saline treated (P < 0.001). Concomitant developments in hematocrits indicated improved plasma refill in glucose treated animals (P < 0.01). While saline treated rats developed irreversible shock and died within 3 hr of bleeding, glucose treated rats had a MAP of 52 +/- 2 (mean +/- SEM) mm Hg by the end of hemorrhage (P < 0.01). All glucose-treated rats recovered and survived the seven-day observation period. It is concluded that glucose infusion leading to hepatic glycogen repletion alters outcome after experimental hemorrhage in food deprived animals. These experimental results may be of clinical relevance, since elective surgery is generally performed after overnight fasting, which substantially reduces the hepatic glycogen reserve.