SGLT2-inhibitors are potent antihyperglycemic drugs for patients with type 2 diabetes and have been shown to reduce body weight. However, it is unclear which body compartments are reduced and to what extent. In this longitudinal observational study, we analyzed the body composition of 27 outpatients with type 2 diabetes mellitus during the first week and up to 6 months after initiation of treatment with SGLT2-inhibitors (n = 18 empagliflozin, n = 9 dapagliflozin) using bioimpedance spectroscopy (BCM, Fresenius). Fluid status of hypertensive patients taking medication with hydrochlorothiazide (n = 14) and healthy persons (n = 16) were analyzed for comparison. At 6 months, HbA1c decreased by 0.8% (IQR 2.3; 0.4), body weight and BMI by 2.6 kg (1.5; 9.3) and 0.9 kg/m2 (0.4; 3.3), respectively. Bioimpedance spectroscopy revealed significant decrease in adipose tissue mass and fat tissue index while lean tissue parameters remained stable. Overhydration (OH) and extracellular water (ECW) decreased by − 0.5 L/1.73 m2 (− 0.1; − 0.9) and − 0.4 L/1.73 m2 (− 0.1; − 0.8) at day 3, respectively, and returned to the initial value after 3 and 6 months. Plasma renin activity increased by 2.1-fold (0.5; 3.6) at 1 month and returned to the initial level at month 3 and 6. Fluid status of patients with SGLT2 inhibitors after 6 months showed no difference from that of hypertensive patients taking hydrochlorothiazide or healthy persons. Body weight reduction under the treatment with SGLT2-inhibitors is caused by reduction of adipose tissue mass and transient loss of extracellular fluid, which is accompanied by upregulation of renin–angiotensin–aldosterone system (RAAS). Permanent loss of extracellular water does not occur under SGLT2 inhibition.
OBJECTIVE Increased plasma levels of free fatty acids occur in obesity and type 2 diabetes and contribute to the development of insulin resistance. Saturated fatty acids (SFAs) such as palmitate especially have lipotoxic effects leading to endoplasmatic reticulum (ER) stress, inflammation, and insulin resistance. Stearoyl-CoA desaturase 1 (SCD1) plays a key role in preventing lipotoxic effects, as it converts SFAs to less harmful monounsaturated fatty acids. Here, we tested the hypothesis that individual differences in the regulation of SCD1 expression by palmitate exist and influence insulin sensitivity and the cellular response to palmitate. RESEARCH DESIGN AND METHODS Palmitate-induced gene expression was studied in primary human myotubes of 39 metabolically characterized individuals, as well as in an SCD1-overexpressing cell culture model. RESULTS SCD1 mRNA expression and inducibility by palmitate in cultured myotubes showed a broad interindividual variation, presumably due to inheritable characteristics of the donors. Overexpression of SCD1 prevented the inflammatory and ER stress response to palmitate exposure. In primary human myotubes, high SCD1 inducibility was associated with a low inflammatory (interleukin [IL]-6, IL-8, and chemokine [CXC motif] ligand 3 [CXCL3]) and ER stress (CCAAT/enhancer binding protein [C/EBP] homologous protein, activating transcription factor 3 [ATF3], and X-box binding protein 1 [XBP1]) response to palmitate exposure. Finally, palmitate-stimulated SCD1 mRNA expression, positively correlated with intramyocellular lipid (IMCL) content of the donors, was measured by 1H-magnetic resonance spectroscopy. After adjustment for IMCL, SCD1 expression and inducibility were positively correlated with insulin sensitivity. CONCLUSIONS We hypothesize that myocellular SCD1 inducibility by palmitate is an individual characteristic that modulates lipid storage, palmitate-induced inflammation, ER stress, and insulin resistance. This may describe individuals with increased capability of innoxious free fatty acid handling and benign triglyceride storage.
Background: Stearoyl-coenzyme A desaturase 1 (SCD1) catalyzes the limiting step of monounsaturated fatty acid synthesis in humans and is an important player in triglyceride generation. SCD1 has been repeatedly implicated in the pathogenesis of metabolic and inflammatory diseases. Therefore it is of great importance to determine SCD1 activity in human samples. In this study we aimed to evaluate a hepatic SCD1 activity index derived from plasma VLDL triglyceride composition as a tool to estimate hepatic SCD1 expression in humans. Additionally, we further evaluated commonly used fatty acid ratios [elongase, de novo lipogenesis, and Δ5 and Δ6 desaturase] in plasma VLDL and hepatic lipid fractions.Design and methods: Liver biopsies and plasma samples were simultaneously collected from 15 individuals. Plasma VLDL was obtained by ultracentrifugation. Hepatic and plasma VLDL lipids were fractionated by thin-layer chromatography, and the fatty acid composition of each fraction was analyzed by gas chromatography. Hepatic SCD1 expression was determined by real-time PCR.Results: Hepatic SCD1 mRNA expression was associated with the product/precursor ratios (16:1/16:0 and 18:1/18:0) of hepatic lipid fractions. The 16:1/16:0 ratio in hepatic and VLDL triglycerides as well as the 18:1/18:0 ratio in plasma VLDL were closely associated with hepatic SCD1 expression. The hepatic de novo lipogenesis index from triglycerides was associated with expression of lipogenic genes [fatty acid synthase (FASN), acetyl-Coenzyme A carboxylase alpha (ACACA), and sterol regulatory element binding transcription factor 1 (SREBP-1)] and is closely reflected by the de novo lipogenesis index in VLDL triglycerides.Conclusion: We demonstrated for the first time that hepatic SCD1 expression can be estimated noninvasively from routine blood samples by measuring the SCD1 activity index in fasting plasma VLDL.
1 July 2011 in The Journal of Clinical Endocrinology & Metabolism
Background/Aims: Glucokinase (GCK) phosphorylates glucose to form glucose 6-phosphate and thereby regulates hepatic glucose disposal and activates hepatic lipogenesis. Hepatic GCK activity is regulated on the level of GCK mRNA expression and by the inhibitory glucokinase regulatory protein. In this study, we aimed to investigate the relation between GCK mRNA expression and markers of lipogenesis as well as liver fat content in human liver biopsies. Additionally, we investigated whether genetic variation in the liver specific GCK promoter determines liver fat content in humans. Methods: Hepatic mRNA expression and liver triglyceride content was analyzed in 50 human liver biopsies. In a second cohort of 330 individuals, liver fat was precisely measured by 1H magnetic resonance spectroscopy. Results: Hepatic GCK mRNA expression is associated with triglyceride content in human liver biopsies (r = 0.50, P = 0.0002). Furthermore, hepatic GCK mRNA expression is associated with lipogenic gene expression (fatty acid synthase, r = 0.49, P = 0.0003; acetyl-coenzyme A carboxylase-α, r = 0.44, P = 0.0015, and acetyl-coenzyme A carboxylase-β, r = 0.48, P = 0.0004) and the de novo lipogenesis index (r = 0.36, P = 0.01). In support of these findings, the single-nucleotide polymorphism rs2041547 in the liver-specific GCK promoter is associated with liver fat content in prediabetic individuals (P = 0.047). Conclusions: In this study, we demonstrate for the first time that GCK mRNA expression is associated with markers of de novo lipogenesis and liver triglyceride content in humans. This suggests that increased GCK activity may induce fatty liver and its metabolic and hepatic consequences in humans. Thus, the widely used approach to nonspecifically activate β-cell and hepatic GCK to treat diabetes mellitus is therefore questionable and may cause serious side effects.
Point-of-care testing (POCT) of coagulation has been proven to be of great value in accelerating emergency treatment. Specific POCT for direct oral anticoagulants (DOAC) is not available, but the effects of DOAC on established POCT have been described. We aimed to determine the diagnostic accuracy of Hemochron® Signature coagulation POCT to qualitatively rule out relevant concentrations of apixaban, rivaroxaban, and dabigatran in real-life patients. We enrolled 68 patients receiving apixaban, rivaroxaban, or dabigatran and obtained blood samples at six pre-specified time points. Coagulation testing was performed using prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), and activated clotting time (ACT+ and ACT-low range) POCT cards. For comparison, laboratory-based assays of diluted thrombin time (Hemoclot) and anti-Xa activity were conducted. DOAC concentrations were determined by liquid chromatography-tandem mass spectrometry. Four hundred and three samples were collected. POCT results of PT/INR and ACT+ correlated with both rivaroxaban and dabigatran concentrations. Insufficient correlation was found for apixaban. Rivaroxaban concentrations at <30 and 95% specificity at PT/INR POCT ≤1.0 and ≤1.1 and ACT+ POCT ≤120 and ≤130 s. Dabigatran concentrations at <30 and 95% specificity at PT/INR POCT ≤1.1 and ≤1.2 and ACT+ POCT ≤100 s. Hemochron® Signature POCT can be a fast and reliable alternative for guiding emergency treatment during rivaroxaban and dabigatran therapy. It allows the rapid identification of a relevant fraction of patients that can be treated immediately without the need to await the results of much slower laboratory-based coagulation tests. Unique identifier, NCT02371070 . Retrospectively registered on 18 February 2015.