👤 Martin Halle

We investigated the relationship between heart failure etiology and lipoprotein subfractions, and to explore their associations with left ventricular dimension and function in heart failure with reduced ejection fraction (HFrEF) patients. Cross-sectional investigation of serum lipoprotein subfractions from 205 HFrEF patients in the SMARTEX heart failure study. Serum levels of triglycerides, cholesterol, free cholesterol, phospholipids, lipoproteins (Apolipoproteins; A-1, A-2, and B), very-low-density (VLDL), intermediate-density (IDL), low-density (LDL), and high-density lipoprotein (HDL) were determined using Stable HFrEF patients [left ventricular ejection fraction (LVEF) ≤ 35%, NYHA class II-III], with ischemic (ICM, n = 119) or non-ischemic (NICM, n = 86) cardiomyopathy were studied. NICM patients had higher levels of 48 lipoproteins compared to ICM patients, including 29 LDL, 13 VLDL, and 6 HDL subfractions [p <0.05]. NICM patients had 22% higher cholesterol and 27% higher remnant cholesterol levels, with 24% more atherogenic ApoB containing subfractions (VLDL, IDL, LDL) (p <0.05). Heart failure etiology and statin treatment explained 23-24% of the variability in cholesterol, free cholesterol, and ApoB (p <0.001). Triglyceride content in some VLDL and LDL subfractions was weakly associated with left ventricular end-diastolic volume, end-diastolic diameter, ejection fraction, and S'. NICM patients had the highest atherosclerotic lipoprotein burden, attributed to elevated ApoB particles and partly due to less statin treatment. The triglyceride content of some VLDL and LDL subfractions was weakly associated with left ventricular structure and function. However, further research is needed to determine their prognostic significance before implementation into strategies for prevention and treatment. Show less

About 30% of patients with active acromegaly experience paradoxically increased growth hormone (GH) secretion during the diagnostic oral glucose tolerance test (OGTT). Endogenous glucose-dependent insulinotropic polypeptide (GIP) is implicated in this paradoxical secretion. We used the GIP receptor (GIPR) antagonist GIP(3-30)NH2 to test the hypothesis that GIP mediates this paradoxical response when GIPR is abundantly expressed in somatotropinomas. A total of 25 treatment-naive patients with acromegaly were enrolled. Each patient underwent one OGTT during simultaneous placebo infusion and one OGTT during a GIP(3-30)NH2 infusion. Blood samples were drawn at baseline and regularly after infusions to measure GH. We assessed pituitary adenoma size by magnetic resonance imaging and GIPR expression by immunohistochemistry on resected somatotropinomas. For mechanistic confirmation, we applied in vitro and ex vivo approaches. The main outcome measure was the effect of GIP(3-30)NH2 on paradoxical GH secretion during OGTT as a measure of GIP involvement. In 4 of 7 patients with paradoxical GH secretion, GIP(3-30)NH2 infusion completely abolished the paradoxical response (P = .0003). Somatotrophs were available from 3 of 4 of these patients, all showing abundant GIPR expression. Adenoma size did not differ between patients with and without paradoxical GH secretion. Of 25 patients with acromegaly, 7 had paradoxical GH secretion during OGTT, and pharmaceutical GIPR blockade abolished this secretion in 4. Corresponding somatotroph adenomas abundantly expressed GIPR, suggesting a therapeutic target in this subpopulation of patients. In vitro and ex vivo analyses confirmed the role of GIP and the effects of the antagonist. Show less

Increasing evidence suggests that fatty acid desaturases, rate-limiting enzymes in unsaturated fatty acid biosynthesis, are important factors in the pathogenesis of lipid-induced insulin resistance. The conversion of dihomogamma linolenic acid (DGLA) into arachidonic acid (AA) in human plasma phospholipids has been shown to be regulated by insulin, suggesting a role for insulin in fatty acid desaturase 1 regulation. However insulin's role in monocyte inflammation associated with obesity and lifestyle disease development is uncertain. We therefore investigated if insulin is able to induce expression of stearoyl-CoA desaturase (SCD, Δ9 desaturase), fatty acid desaturase 1 (FADS1, Δ5 desaturase), and fatty acid desaturase 2 (FADS2, Δ6 desaturase), as well as the sterol regulatory element binding transcription factor 1-c (SREBP-1c) in monocytes. Here, for the first time, we demonstrate that THP-1 monocytes are insulin-responsive in inducing expression of SCD, FADS1, and FADS2 in a time- and dose-dependent manner. Understanding secondary consequences of postprandial hyperinsulinemia may open up new strategies for prevention and/or treatment of obesity-related metabolic complications. Show less