Low-energy diets differing in fibre, red meat and coffee intake equally improve insulin sensitivity in type 2 diabetes: a randomised feasibility trial.

AIMS/HYPOTHESIS: Epidemiological studies have found that a diet high in fibre and coffee, but low in red meat, reduces the risk for type 2 diabetes. We tested the hypothesis that these nutritional modifications differentially improve whole-body insulin sensitivity (primary outcome) and secretion. METHODS: Inclusion criteria were: age 18-69 years, BMI ≥ 30 kg/m(2), type 2 diabetes treated with diet, metformin or acarbose and known disease duration of ≤ 5 years. Exclusion criteria were: HbA1c >75 mmol/mol (9.0%), type 1 or secondary diabetes types and acute or chronic diseases including cancer. Patients taking any medication affecting the immune system or insulin sensitivity, other than metformin, were also excluded. Of 59 patients (randomised using randomisation blocks [four or six patients] with consecutive numbers), 37 (54% female) obese type 2 diabetic patients completed this controlled parallel-group 8-week low-energy dietary intervention. The participants consumed either a diet high in cereal fibre (whole grain wheat/rye: 30-50 g/day) and coffee (≥ 5 cups/day), and free of red meat (L-RISK, n = 17) or a diet low in fibre (≤ 10 g/day), coffee-free and high in red meat (≥ 150 g/day) diet (H-RISK, n = 20). Insulin sensitivity and secretion were assessed by hyperinsulinaemic-euglycaemic clamp and intravenous glucose tolerance tests with isotope dilution. Whole-body and organ fat contents were measured by magnetic resonance imaging and spectroscopy. RESULTS: Whole-body insulin sensitivity increased in both groups (mean [95% CI]) (H-RISK vs L-RISK: 0.8 [0.2, 1.4] vs 1.0 [0.4, 1.7]mg kg(-1) min(-1), p = 0.59), while body weight decreased (-4.8% [-6.1%, -3.5%] vs -4.6% [-6.0%, -3.3%], respectively). Hepatic insulin sensitivity remained unchanged, whereas hepatocellular lipid content fell in both groups (-7.0% [-9.6%, -4.5%] vs -6.7% [-9.5%, -3.9%]). Subcutaneous fat mass (-1,553 [-2,767, -340] cm(3) vs -751 [-2,047; 546] cm(3), respectively) visceral fat mass (-206 [-783, 371] cm(3) vs -241 [-856, 373] cm(3), respectively) and muscle fat content (-0.09% [-0.16%, -0.02%] vs -0.02% [-0.10%, 0.05%], respectively) decreased similarly. Insulin secretion remained unchanged, while the proinflammatory marker IL-18 decreased only after the L-RISK diet. CONCLUSIONS/INTERPRETATION: No evidence of a difference between both low-energy diets was identified. Thus, energy restriction per se seems to be key for improving insulin action in phases of active weight loss in obese type 2 diabetic patients, with a potential improvement of subclinical inflammation with the L-RISK diet. TRIAL REGISTRATION: Clinicaltrials.gov NCT01409330. FUNDING: This study was supported by the Ministry of Science and Research of the State of North Rhine-Westphalia (MIWF NRW), the German Federal Ministry of Health (BMG), the Federal Ministry for Research (BMBF) to the Center for Diabetes Research (DZD e.V.) and the Helmholtz Alliance Imaging and Curing Environmental Metabolic Diseases (ICEMED).

Normal values for intima-media thickness of the common carotid artery--an update following a novel risk factor profiling.

BACKGROUND: There is a widely approved influence of novel risk factors like the body fat distribution and the associated metabolic syndrome, subclinical inflammation, insulin resistance and prediabetic disturbances in glucose metabolism on the progression of atherosclerosis. Former studies examining normal values for intima-media thickness (IMT) did not consider all of these new study results in detail. We therefore aimed to assess an update on age- and gender-specific normal values for IMT accounting for these novel risk factors. PATIENTS AND METHODS: We evaluated IMT by high-resolution ultrasound (13 MHz) on the far wall of the common carotid artery in 801 subjects without cardiovascular disease (428 women aged 46.2±12.9 years; 373 men aged 47.3±13.3 years). After precise evaluation and exclusion of 14 cardiovascular risk factors, 90% limits of IMT were determined by parametric statistics. RESULTS: The reference limits of IMT according to the age classes 18-29, 30-39, 40-49 and 50-59 years were estimated as 0.47, 0.59, 0.67 and 0.70 mm in women and 0.47, 0.62, 0.72 and 0.80 mm in men. CONCLUSIONS: Age and gender-specific normal values for IMT are lower than reported in former studies after additionally accounting for novel cardiovascular risk factors. The still widely regarded upper IMT limit of 1 mm must be strictly regarded as obsolete.

Surrogate measures of first-phase insulin secretion versus reference methods intravenous glucose tolerance test and hyperglycemic clamp: a systematic review and meta-analyses.

INTRODUCTION: In this systematic review, we investigated the diagnostic accuracy of surrogate measures of insulin secretion based on fasting samples and the oral glucose tolerance test (OGTT). The first phase of insulin secretion was calculated using two gold standard methods; the hyperglycemic clamp (HGC) test and intravenous glucose tolerance test (IVGTT). RESEARCH DESIGN AND METHODS: We conducted searches in the PubMed, Cochrane Central, and Web of Science databases, the last of which was conducted at the end of June 2021. Studies were included that measured first-phase insulin secretion in adults using both a gold-standard reference method (either HGC or IVGTT) and one or more surrogate measures from either fasting samples, OGTT or a meal-tolerance test. QUADAS-2, a revised tool for the quality assessment of diagnostic accuracy studies, was used for quality assessment. Random-effects meta-analyses were performed to examine the correlation between first-phase measured with gold standard and surrogate methods. RESULTS: A total of 33 articles, encompassing 5362 individuals with normal glucose tolerance, pre-diabetes or type 2 diabetes, were included in our systematic review. Homeostatic model assessment (HOMA)-beta and Insulinogenic Index 30 (IGI(30)) were the surrogate measures validated in the largest number of studies (17 and 13, respectively). HOMA-beta's pooled correlation to the reference methods was 0.48 (95% CI 0.40 to 0.56) The pooled correlation of IGI to the reference methods was 0.61 (95% CI 0.54 to 0.68). The surrogate measures with the highest correlation to the reference methods were Kadowaki (0.67 (95% CI 0.61 to 0.73)) and Stumvoll's first-phase secretion (0.65 (95% CI 0.58 to 0.71)), both calculated from an OGTT. CONCLUSIONS: Surrogate measures from the first 30 min of an OGTT capture the first phase of insulin secretion and are a good choice for epidemiological studies. HOMA-beta has a moderate correlation to the reference methods but is not a measure of the first phase specifically. PROSPERO REGISTRATION NUMBER: The meta-analysis was registered at PROSPERO (Id: CRD42020169064) before inclusion started.

Effect of genetic variation in Kv1.3 on olfactory function.

BACKGROUND: Olfactory function is reduced in aged humans and diabetes mellitus patients. However, little is known about the pathogenic mechanisms leading to olfactory dysfunction. Recently, it has been shown that the voltage-gated potassium channel Kv1.3 is regulated by insulin and is highly expressed in the olfactory bulb. Furthermore, the function of this channel is associated with olfaction in mice and with glucose metabolism in mice and men. We therefore hypothesized that a functionally relevant polymorphism in Kv1.3 might alter olfactory function. METHODS: We investigated a group of 94 healthy subjects (male: n = 58, female: n = 36) for olfactory function and genotyped them for rs2821557 in the human Kv1.3 gene. Olfactory function was tested using standardised sniffing sticks, and parameters of glucose metabolism were assessed. RESULTS: We found a significant olfactory impairment in male homozygous carriers of the Kv1.3 polymorphism rs2821557 (recessive model, p = 0.018, adjusted for age) that could not be determined in female subjects due to the very small number of homozygous minor allele carriers (n = 1). In addition, we found a significant correlation of olfactory dysfunction with higher HbA1c and fasting plasma glucose (p = 0.004 and p = 0.001, both adjusted for age). We also found a loss of olfactory function with age (p = 0.006). Gender, body mass index and insulin sensitivity did not alter smelling function. CONCLUSIONS: The presence of genetic variation in Kv1.3 is associated with decreased olfactory function in healthy subjects. As olfactory function, glucose metabolism and genetic variation in Kv1.3 seem to be associated, further studies are needed to clarify the underlying mechanisms.

Effects of tetrahydrobiopterin on nitric oxide bioavailability and renal hemodynamics in healthy volunteers.

BACKGROUND: The endothelial nitric oxide (NO) system plays a central role in regulating vascular tone. Endothelial dysfunction has been closely linked to reduced activity in the NO system. Tetrahydrobiopterin (BH4) is an essential cofactor of all NO synthase isoforms. METHODS: We examined the effects of BH4 on the NO system assessed by measurement of serum cGMP levels and NO breakdown products (NOx) in 12 healthy volunteers. RESULTS: Application of a total of 19 mg/kg BH4 intravenously (i.v.) over 3 hours led to a dose-dependent increase in serum cGMP concentrations from a median 3.3 nM (interquartile range [IQR] 1.1-5.6) to 5.7 nM (IQR 2.4-13.3, p=0.008) and NOx from a median 49.3 microM (IQR 39.8-56.6) to 59.7 microM (39.6-85.5) (p=0.058). Systemic and renal hemodynamics measured by inulin and p-aminohippuric acid (PAH) clearance remained unchanged. Plasma renin activity was significantly increased (2.0 [IQR 1.0-2.8] to 2.3 ng AngI/mL per hour [IQR 1.7-4.0], p=0.045), whereas aldosterone, erythropoietin and B-type natriuretic peptide levels did not change. In a second study, oral BH4 given over 3 days (800 mg/day) similarly increased serum cGMP and ameliorated the depressive effects of the NO synthase inhibitor L-NAME (1.5 mg/kg i.v.) on the glomerular filtration rate. CONCLUSIONS: Application of BH4 in high doses is safe and enhances formation of cGMP, pointing to increased bioavailability of NO.

Loss of pain perception in diabetes is dependent on a receptor of the immunoglobulin superfamily.

Molecular events that result in loss of pain perception are poorly understood in diabetic neuropathy. Our results show that the receptor for advanced glycation end products (RAGE), a receptor associated with sustained NF-kappaB activation in the diabetic microenvironment, has a central role in sensory neuronal dysfunction. In sural nerve biopsies, ligands of RAGE, the receptor itself, activated NF-kappaBp65, and IL-6 colocalized in the microvasculature of patients with diabetic neuropathy. Activation of NF-kappaB and NF-kappaB-dependent gene expression was upregulated in peripheral nerves of diabetic mice, induced by advanced glycation end products, and prevented by RAGE blockade. NF-kappaB activation was blunted in RAGE-null (RAGE(-/-)) mice compared with robust enhancement in strain-matched controls, even 6 months after diabetes induction. Loss of pain perception, indicative of long-standing diabetic neuropathy, was reversed in WT mice treated with soluble RAGE. Most importantly, loss of pain perception was largely prevented in RAGE(-/-) mice, although they were not protected from diabetes-induced loss of PGP9.5-positive plantar nerve fibers. These data demonstrate, for the first time to our knowledge, that the RAGE-NF-kappaB axis operates in diabetic neuropathy, by mediating functional sensory deficits, and that its inhibition may provide new therapeutic approaches.

Empagliflozin as add-on to metformin plus sulphonylurea in patients with type 2 diabetes.

This study investigated the long-term efficacy and safety of empagliflozin as add-on to metformin plus sulphonylurea in patients with type 2 diabetes mellitus (T2DM). Of 666 patients treated with empagliflozin 10 mg, empagliflozin 25 mg or placebo once daily for 24 weeks, 472 patients (70.9%) were treated in a double-blind extension trial for ≥52 weeks. Pre-specified exploratory endpoints included changes from baseline in HbA(1c), weight and blood pressure at week 76. At week 76, adjusted mean differences versus placebo in change from baseline in HbA(1c) were -0.7% (-8 mmol/mol) with empagliflozin 10 mg or 25 mg (both p<0.001), in weight were -1.8 kg and -1.6 kg with empagliflozin 10 mg and 25 mg, respectively (both p<0.001), and in systolic blood pressure (SBP) were -2.2 mmHg with empagliflozin 10 mg (p=0.021) and -2.1 mmHg with empagliflozin 25 mg (p=0.029). Sensitivity analyses provided consistent results for HbA1c and weight, but showed no significant difference between empagliflozin and placebo in change from baseline in SBP. Adverse events (AEs) were reported in 81.7%, 82.0% and 81.3% of patients on empagliflozin 10 mg, 25 mg and placebo, respectively. Confirmed hypoglycaemic AEs (glucose ≤3.9 mmol/l and/or requiring assistance) were reported in 23.7%, 19.4% and 15.6% of patients on empagliflozin 10 mg, 25 mg and placebo, respectively; one patient each on empagliflozin 10mg and placebo required assistance. In conclusion, empagliflozin as add-on to metformin plus sulphonylurea for 76 weeks was well tolerated and led to sustained reductions in HbA1c and weight versus placebo. CLINICALTRIALS.GOV: NCT01289990.

Association of peroxisome proliferator-activated receptor gamma 2 Pro-12-Ala polymorphism with endometriosis.

We explored the association of the PPAR-gamma2 (peroxisome proliferator-activated receptor) Pro-12-Ala polymorphism with endometriosis in a case-control study with 51 women with endometriosis stages I-IV and 55 control women without endometriosis. The 12-Pro allele of PPAR-gamma2 may have protective effects avoiding the development and progression of endometriosis.

Plasma concentrations of the vasoactive peptide fragments mid-regional pro-adrenomedullin, C-terminal pro-endothelin 1 and copeptin in hemodialysis patients: associated factors and prediction of mortality.

Vasopressin, endothelin and adrenomedullin are vasoactive peptides that regulate vascular tone and might play a role in hypertensive diseases. Recently, laboratory assays have been developed to measure stable fragments of vasopressin, endothelin and adrenomedullin. Little is known about their diagnostic and prognostic value in hemodialysis patients. In this study, we measured the plasma concentration of copeptin, mid-regional-pro-adrenomedullin (MR-pro-ADM) and C-terminal pro-endothelin 1 (CT-pro-ET1) in stable ambulatory hemodialysis patients (n = 239) and investigated their associations with clinical factors and mortality. In all patients enrolled, the plasma concentrations of copeptin, MR-pro-ADM and CT-pro-ET1 were largely elevated with a median concentration of 132 pmol/L (interquartile range [IQR] 78-192) for copeptin, 1.26 nmol/L (IQR 1.02-1.80) for MR-pro-ADM and 149 pmol/L (IQR 121-181) for CT-pro-ET1. The plasma concentrations of all vasoactive peptide fragments correlated with time on dialysis and plasma ß2-microglobulin concentration and were negatively correlated to residual diuresis. The plasma concentration of MR-pro-ADM was a strong predictor of all-cause (univariate hazard ratio for a 10-fold increase 9.94 [3.14;32], p<0.0001) and cardiovascular mortality (hazard ratio 34.87 [5.58;217], p = 0.0001) within a 3.8-year follow-up. The associations remained stable in models adjusted for dialysis specific factors and were attenuated in a full model adjusted for all prognostic factors. Plasma copeptin concentration was weakly associated with cardiovascular mortality (only in univariate analysis) and CT-pro-ET1 was not associated with mortality at all. In conclusion, vasoactive peptide fragments are elevated in hemodialysis patients because of accumulation and, most likely, increased release. Increased concentrations of MR-pro-ADM are predictive of mortality.

Management of disseminated intravascular coagulopathy with direct factor Xa inhibitor rivaroxaban in Klippel-Trénaunay syndrome.

Klippel-Trénaunay syndrome (KTS) is a rare congenital anomaly characterized by malformation of lymph and blood vessels as well as growth disturbance of soft tissue and bone. The clinical picture is variable and associated with an increased risk of thromboembolic events mediated by intravascular coagulopathy in venous malformations. Here, we report on a male patient with KTS suffering from recurrent deep vein thrombosis (DVT) and life-threatening bleeding due to consumptive coagulopathy. Furthermore, we describe the successful long-term anticoagulant management with rivaroxaban.

Identification of the amino acids 300-600 of IRS-2 as 14-3-3 binding region with the importance of IGF-1/insulin-regulated phosphorylation of Ser-573.

Phosphorylation of insulin receptor substrate (IRS)-2 on tyrosine residues is a key event in IGF-1/insulin signaling and leads to activation of the PI 3-kinase and the Ras/MAPK pathway. Furthermore, phosphorylated serine/threonine residues on IRS-2 can induce 14-3-3 binding. In this study we searched IRS-2 for novel phosphorylation sites and investigated the interaction between IRS-2 and 14-3-3. Mass spectrometry identified a total of 24 serine/threonine residues on IRS-2 with 12 sites unique for IRS-2 while the other residues are conserved in IRS-1 and IRS-2. IGF-1 stimulation led to increased binding of 14-3-3 to IRS-2 in transfected HEK293 cells and this binding was prevented by inhibition of the PI 3-kinase pathway and an Akt/PKB inhibitor. Insulin-stimulated interaction between endogenous IRS-2 and 14-3-3 was observed in rat hepatoma cells and in mice liver after an acute insulin stimulus and refeeding. Using different IRS-2 fragments enabled localization of the IGF-1-dependent 14-3-3 binding region spanning amino acids 300-600. The 24 identified residues on IRS-2 included several 14-3-3 binding candidates in the region 300-600. Single alanine mutants of these candidates led to the identification of serine 573 as 14-3-3 binding site. A phospho-site specific antibody was generated to further characterize serine 573. IGF-1-dependent phosphorylation of serine 573 was reduced by inhibition of PI 3-kinase and Akt/PKB. A negative role of this phosphorylation site was implicated by the alanine mutant of serine 573 which led to enhanced phosphorylation of Akt/PKB in an IGF-1 time course experiment. To conclude, our data suggest a physiologically relevant role for IGF-1/insulin-dependent 14-3-3 binding to IRS-2 involving serine 573.

Sensitive troponins--which suits better for hemodialysis patients? Associated factors and prediction of mortality.

BACKGROUND: In hemodialysis patients, elevated plasma troponin concentrations are a common finding that has even increased with the advent of newly developed sensitive assays. However, the interpretation and relevance of this is still under debate. METHODS: In this cross-sectional study, we analyzed plasma concentrations of sensitive troponin I (TnI) and troponin T (TnT) in stable ambulatory hemodialysis patients (n = 239) and investigated their associations with clinical factors and mortality. RESULTS: In all of the enrolled patients, plasma TnI or TnT was detectable at a median concentration of 14 pg/ml (interquartile range: 7-29) using the Siemens TnI ultra assay and 49 pg/ml (31-74) using the Roche Elecsys high sensitive TnT assay. Markedly more patients exceeded the 99th percentile for TnT than for TnI (95% vs. 14%, p<0.0001). In a multivariate linear regression model, TnT was independently associated with age, gender, systolic dysfunction, time on dialysis, residual diuresis and systolic blood pressure, whereas TnI was independently associated with age, systolic dysfunction, pulse pressure, time on dialysis and duration of a HD session. During a follow-up period of nearly two years, TnT concentration above 38 pg/mL was associated with a 5-fold risk of death, whereas elevation of TnI had a gradual association to mortality. CONCLUSION: In hemodialysis patients, elevations of plasma troponin concentrations are explained by cardiac function and dialysis-related parameters, which contribute to cardiac strain. Both are highly predictive of increased risk of death.