Allan Flyvbjerg

Context The impact of obesity on glucose homeostasis has a high interindividual variability, which may be partially explained by different adipokines concentrations. Leptin regulates energy balance and metabolism, and although its plasma levels are proportional to fat mass, they vary significantly across individuals with the same level of adiposity. Objective We tested whether glucose homeostasis differs in subjects with similar degrees of adiposity but different leptin levels. Methods We analyzed 1,290 healthy adults from the RISC study cohort (30-60 years, M/F 577/713, BMI 25 ± 3 kg/m²) characterized for body composition and metabolic variables with a 75-g OGTT, euglycemic-hyperinsulinemic clamp, β-cell function and lipidomics. Results Individuals were divided into relatively high and low leptin (RHL and RLL) if they were above or below the sex-specific leptin-fat mass(%) regression. Despite similar glucose tolerance, RHL showed markedly higher fasting and OGTT insulin concentration (+30% and +29% respectively, p < 0.0001) and secretion (+17% and +11% respectively, p < 0.0001). Regardless of BMI, RHL individuals had lower whole-body (-17-23%, p < 0.0001) and adipose tissue insulin sensitivity (-24%, p < 0.0001) compared to RLL. Notably, lean RHL individuals showed similar insulin sensitivity and β-cell function to RLL individuals with overweight/obesity. Conclusion Subjects with leptin levels that are inappropriately elevated for their fat mass show whole-body/adipose tissue insulin resistance and hyperinsulinemia, regardless of BMI.

Objectives: The aim of our study was to investigate if the 24-hour excretion of the urinary markers for oxidative stress to DNA and RNA, measured as 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydro-guanosine (8-oxoGuo), respectively, were increased in obese individuals with or without hypertension compared to lean controls. Methods: A total of 63 obese hypertensive men (obeseHT), 40 obese normotensive men (obeseNT) and 27 lean normotensive men (leanNT) were included in the study. Body mass index (BMI) was between 20.0 and 24.9 kg/m² in leanNT participants and ≥30 kg/m² in obese participants. Hypertension was defined as a mean 24-hour systolic ambulatory blood pressure (AMBP) ≥ 130 mmHg or a mean 24-hour diastolic AMBP ≥80 mmHg and normotension as mean 24-hour AMBP p = .002) and post hoc tests showed a significant difference between leanNT and obeseHT (p = .001) as well as obeseNT (p = .002), whereas the two obese groups did not differ (p = .6). No statistically significant differences in 8-oxodG concentrations were observed between the three groups (p = .3). Conclusion: The measurement of urinary excretion of 8-oxoGuo suggests that obesity in men, but not hypertension, is associated with increased oxidative damage to RNA.

Background/Aims: Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a marker for acute kidney injury and cardiovascular outcome. However, the relative importance of inflammation versus kidney function on plasma NGAL levels is uncertain, making the interpretation of plasma NGAL unclear. Accordingly, we investigated the relationship between plasma NGAL, inflammation and kidney function in patients with myocardial infarction (MI). Methods: We prospectively included 584 patients with acute ST-segment elevation MI (STEMI) treated with primary percutaneous coronary intervention (PCI) from 2006 to 2008. Blood samples were drawn immediately before PCI. Additionally, we included 42 patients who had 4 blood samples drawn before and after PCI. Plasma NGAL was measured using a time-resolved immunofluorometric assay. Cross-sectional analyses were performed in these two single-center, prospective study cohorts. Results: Estimated glomerular filtration rate (eGFR) was associated significantly more strongly with plasma NGAL when eGFR was abnormal compared to normal eGFR: a decrease in eGFR of 10 ml/min was associated with an increase in NGAL of 27% (18-36%) versus 4% (1-7%), respectively (p < 0.001). Leukocyte count and C-reactive protein were the main determinants of plasma NGAL in patients with normal eGFR, whereas eGFR was the main determinant at reduced kidney function. Conclusions: eGFR determines the association of NGAL with either inflammation or kidney function; in patients with normal eGFR, plasma NGAL reflects inflammation but when eGFR is reduced, plasma NGAL reflects kidney function, highlighting the dual perception of plasma NGAL. From a clinical perspective, eGFR may be used to guide the interpretation of elevated NGAL levels in patients with STEMI.

In the metabolism of acetate several enzymes are involved, which play an important role in free fatty acid oxidation. Fatty acid metabolism is altered in diabetes patients and therefore acetate might serve as a marker for pathological changes in the fuel selection of cells, as these changes occur in diabetes patients. Acetylcarnitine is a metabolic product of acetate, which enables its transport into the mitochondria for energy production. This study investigates whether the ratio of acetylcarnitine to acetate, measured by noninvasive hyperpolarized [1‐13C]acetate magnetic resonance spectroscopy, could serve as a marker for myocardial, hepatic, and renal metabolic changes in rats with Streptozotocin (STZ)‐induced diabetes in vivo. We demonstrate that the conversion of acetate to acetylcarnitine could be detected and quantified in all three organs of interest. More interestingly, we found that the hyperpolarized acetylcarnitine to acetate ratio was independent of blood glucose levels and prolonged hyperglycemia following diabetes induction in a type‐1 diabetes model.

OBJECTIVE Patients with acute myocardial infarction (MI) have increased risk of developing type 2 diabetes mellitus (T2DM). Adiponectin is an insulin-sensitizing hormone produced in adipose tissue, directly suppressing hepatic gluconeogenesis, stimulating fatty acid oxidation and glucose uptake in skeletal muscle and insulin secretion. In healthy humans, low plasma adiponectin levels associate with increased risk of T2DM; however, the relationship between adiponectin and T2DM in patients with MI has never been investigated. RESEARCH DESIGN AND METHODS We prospectively included 666 patients with ST-segment elevation MI, without diabetes, treated with percutaneous coronary intervention, from September 2006 to December 2008 at a tertiary cardiac center. Blood samples were drawn before intervention, and total plasma adiponectin was measured in all samples. During follow-up (median 5.7 years [interquartile range 5.3–6.1]) 6% (n = 38) developed T2DM. Risk of T2DM was analyzed using a competing risk analysis. RESULTS Low adiponectin levels were associated with increased risk of T2DM (P < 0.001). Even after adjustment for confounding risk factors (age, sex, hypertension, hypercholesterolemia, current smoking, previous MI, BMI, blood glucose, total cholesterol, HDL, LDL, triglyceride, estimated glomerular filtration rate, C-reactive protein, peak troponin I, and proatrial natriuretic peptide), low adiponectin levels remained an independent predictor of T2DM (hazard ratio [HR] 5.8 [2.3–15.0]; P < 0.001). Importantly, plasma adiponectin added to the predictive value of blood glucose, with the combination of high blood glucose and low plasma adiponectin, vastly increasing the risk of developing T2DM (HR 9.6 [3.7–25.3]; P < 0.001). CONCLUSIONS Low plasma adiponectin levels are independently associated with increased risk of T2DM in patients with MI and added significantly to the predictive value of blood glucose.

Increasing evidence links complement activation through the lectin pathway to diabetic nephropathy. Adverse complement recognition of proteins modified by glycation has been suggested to trigger complement auto-attack in diabetes. H-ficolin (also known as ficolin-3) is a pattern recognition molecule that activates the complement cascade on binding to glycated surfaces, but the role of H-ficolin in diabetic nephropathy is unknown. We aimed to investigate the association between circulating H-ficolin levels and the incidence of microalbuminuria in type 1 diabetes. We measured baseline H-ficolin levels and tracked the development of persistent micro- and macroalbuminuria in a prospective 18 year observational follow-up study of an inception cohort of 270 patients with newly diagnosed type 1 diabetes. Patients were followed for a median of 18 years (range 1–22 years). During follow-up, 75 patients developed microalbuminuria, defined as a persistent urinary albumin excretion rate (UAER) above 30 mg/24 h. When H-ficolin levels were divided into quartile groups an unadjusted Cox proportional hazards regression model showed a significant association with risk of incident microalbuminuria during follow-up (HR, fourth vs first quartile, 2.45; 95% CI 1.24, 4.85) (p = 0.01). This remained significant after adjusting for HbA_1c, systolic blood pressure, smoking and baseline UAER (HR 2.09; 95% CI 1.03, 4.25) (p = 0.04). Our data suggest that high levels of the complement activating molecule H-ficolin are associated with an increased risk of future progression to microalbuminuria in patients with newly diagnosed type 1 diabetes.

Objective: End-point bioassays based on thymidine or sulfate incorporation have demonstrated that glucocorticoid (GC) treatment inhibits serum IGF1 action, but the mechanism is unknown as serum IGF1 concentrations have been reported to either increase or remain unchanged.Aim: To investigate whether GC treatment affects the ability of serum to activate the IGF1 receptor (IGF1R) in vitro (i.e. bioactive IGF1), using a specific cell-based IGF1 kinase receptor activation assay.Subjects and methods: Twenty children with stable asthma (age 7.7–13.8 years) treated for 1 week with 5 mg prednisolone in a randomized, double-blind, placebo-controlled crossover study. Non-fasting serum samples were collected in the afternoon after each 7-day period and assayed for bioactive IGF1, free IGF1, total IGFs, IGF-binding proteins (IGFBPs), and insulin.Results: Prednisolone treatment reduced IGF1 bioactivity by 12.6% from 2.22±0.18 to 1.94±0.15 μg/l (P=0.01) compared with placebo. In contrast, no changes were observed for (μg/l; placebo vs prednisolone) total IGF1 (215±27 vs 212±24), free IGF1 (1.50±0.16 vs 1.43±0.17), total IGF2 (815±26 vs 800±31), IGFBP3 (3140±101 vs 3107±95), IGFBP2 (238±21 vs 220±19), IGFBP1 (32±6 vs 42±10), or IGFBP1-bound IGF1 (24±5 vs 26±7). Insulin remained unchanged as did IGFBP levels as estimated by western ligand blotting. Prednisolone had no direct effects on IGF1R phosphorylation.Conclusions: Our study gives evidence that GC treatment induces a circulating substance that is able to inhibit IGF1R activation in vitro without affecting circulating free or total IGF1. This may be one of the mechanisms by which GC inhibits IGF1 action in vivo. However, the nature of this circulating substance remains to be identified.