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48 result(s) for "Tietge, Uwe J.F"
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Cell-free, high-density lipoprotein–specific phospholipid efflux assay predicts incident cardiovascular disease
BACKGROUNDCellular cholesterol efflux capacity (CEC) is a better predictor of cardiovascular disease (CVD) events than HDL-cholesterol (HDL-C) but is not suitable as a routine clinical assay.METHODSWe developed an HDL-specific phospholipid efflux (HDL-SPE) assay to assess HDL functionality based on whole plasma HDL apolipoprotein-mediated solubilization of fluorescent phosphatidylethanolamine from artificial lipid donor particles. We first assessed the association of HDL-SPE with prevalent coronary artery disease (CAD): study I included NIH severe-CAD (n = 50) and non-CAD (n = 50) participants, who were frequency matched for sex, BMI, type 2 diabetes mellitus, and smoking; study II included Japanese CAD (n = 70) and non-CAD (n = 154) participants. We also examined the association of HDL-SPE with incident CVD events in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study comparing 340 patients with 340 controls individually matched for age, sex, smoking, and HDL-C levels.RESULTSReceiver operating characteristic curves revealed stronger associations of HDL-SPE with prevalent CAD. The AUCs in study I were as follows: HDL-SPE, 0.68; apolipoprotein A-I (apoA-I), 0.62; HDL-C, 0.63; and CEC, 0.52. The AUCs in study II were as follows: HDL-SPE, 0.83; apoA-I, 0.64; and HDL-C, 0.53. Also longitudinally, HDL-SPE was significantly associated with incident CVD events independent of traditional risk factors with ORs below 0.2 per SD increment in the PREVEND study (P < 0.001).CONCLUSIONHDL-SPE could serve as a routine clinical assay for improving CVD risk assessment and drug discovery.TRIAL REGISTRATIONClinicalTrials.gov NCT01621594.FUNDINGNHLBI Intramural Research Program, NIH (HL006095-06).
Effect of the prebiotic fiber inulin on cholesterol metabolism in wildtype mice
Dietary non-digestible carbohydrates are perceived to improve health via gut microbiota-dependent generation of products such as short-chain fatty acids (SCFA). In addition, SCFA are also precursors for lipid and cholesterol synthesis potentially resulting in unwanted effects on lipid metabolism. Inulin is a widely used model prebiotic dietary fiber. Inconsistent reports on the effects of inulin on cholesterol homeostasis have emerged in humans and preclinical models. To clarify this issue, the present study aimed to provide an in-depth characterization of the effects of short-chain (sc)- and long-chain (lc)- inulin on cholesterol synthesis, absorption and elimination in mice. Feeding wildtype C57BL/6J mice diets supplemented with 10% (w/w) of either sc- or lc-inulin for two weeks resulted in approximately 2.5-fold higher fecal SCFA levels (P < 0.01) compared with controls, but had no significant effects on plasma and liver lipids. Subtle shifts in fecal and plasma bile acid species were detected with beta-muricholic acid increasing significantly in plasma of the inulin fed groups (1.7-fold, P < 0.05). However, neither sc-inulin nor lc-inulin affected intestinal cholesterol absorption, mass fecal cholesterol excretion or trans-intestinal cholesterol excretion (TICE). Combined, our data demonstrate that sc- and lc-inulin have no adverse effects on cholesterol metabolism in mice despite increased generation of SCFA.
HDL Cholesterol Efflux Capacity is Impaired in Severe Short-Term Hypothyroidism Despite Increased HDL Cholesterol
Abstract Context Severe hypothyroidism has profound effects on lipoprotein metabolism including high-density lipoprotein (HDL) cholesterol elevations but effects on HDL function metrics are unknown. Objective To determine the impact of severe short-term hypothyroidism on HDL particle characteristics, HDL cholesterol efflux capacity (CEC), and HDL antioxidative capacity. Design Observational study with variables measured during severe short-term hypothyroidism (median TSH 81 mU/L) and after 20 weeks of thyroid hormone supplementation (median TSH 0.03 mU/L) (Netherlands Trial Registry ID 7228). Setting University hospital setting in The Netherlands. Patients Seventeen patients who had undergone a total thyroidectomy for differentiated thyroid carcinoma. Main outcome measures HDL particle characteristics (nuclear magnetic resonance spectrometry), CEC (human THP-1-derived macrophage foam cells and apolipoprotein B-depleted plasma), and HDL anti-oxidative capacity (inhibition of low-density lipoprotein oxidation). Results During hypothyroidism plasma total cholesterol, HDL cholesterol and apolipoprotein A-I were increased (P ≤ 0.001). HDL particle concentration was unchanged, but there was a shift in HDL subclasses toward larger HDL particles (P < 0.001). CEC was decreased (P = 0.035), also when corrected for HDL cholesterol (P < 0.001) or HDL particle concentration (P = 0.011). HDL antioxidative capacity did not change. Conclusion During severe short-term hypothyroidism CEC, an important antiatherogenic metric of HDL function, is impaired. HDL cholesterol and larger HDL particles are increased but HDL particle concentration is unchanged. Combined, these findings suggest that HDL quality and quantity are not improved, reflecting dysfunctional HDL in hypothyroidism.
Preconceptional Maternal Bile Acids and Birth Weight of Neonates
Preconceptional maternal bile acid species are significantly associated with birth weight of the offspring.Preconceptional maternal bile acid species are significantly associated with birth weight of the offspring.
High Fat Feeding Induces Hepatic Fatty Acid Elongation in Mice
Background: High-fat diets promote hepatic lipid accumulation. Paradoxically, these diets also induce lipogenic gene expression in rodent liver. Whether high expression of these genes actually results in an increased flux through the de novo lipogenic pathway in vivo has not been demonstrated. Methodology/Principal Findings: To interrogate this apparent paradox, we have quantified de novo lipogenesis in C57Bl/6J mice fed either chow, a high-fat or a n-3 polyunsaturated fatty acid (PUFA)-enriched high-fat diet. A novel approach based on mass isotopomer distribution analysis (MIDA) following 1-¹³C acetate infusion was applied to simultaneously determine de novo lipogenesis, fatty acid elongation as well as cholesterol synthesis. Furthermore, we measured very low density lipoprotein-triglyceride (VLDL-TG) production rates. High-fat feeding promoted hepatic lipid accumulation and induced the expression of lipogenic and cholesterogenic genes compared to chow-fed mice: induction of gene expression was found to translate into increased oleate synthesis. Interestingly, this higher lipogenic flux (+74 μg/g/h for oleic acid) in mice fed the high-fat diet was mainly due to an increased hepatic elongation of unlabeled palmitate (+66 μg/g/h) rather than to elongation of de novo synthesized palmitate. In addition, fractional cholesterol synthesis was increased, i.e. 5.8±0.4% vs. 8.1±0.6% for control and high fat-fed animals, respectively. Hepatic VLDL-TG production was not affected by high-fat feeding. Partial replacement of saturated fat by fish oil completely reversed the lipogenic effects of high-fat feeding: hepatic lipogenic and cholesterogenic gene expression levels as well as fatty acid and cholesterol synthesis rates were normalized. Conclusions/Significance: High-fat feeding induces hepatic fatty acid synthesis in mice, by chain elongation and subsequent desaturation rather than de novo synthesis, while VLDL-TG output remains unaffected. Suppression of lipogenic fluxes by fish oil prevents from high fat diet-induced hepatic steatosis in mice.
Anti-oxidative function of follicular fluid HDL and outcomes of modified natural cycle-IVF
High density lipoproteins (HDL) are the main cholesterol carriers in follicular fluid (FF), the natural environment of oocyte development. Additionally, HDL have critical biological functions such as anti-oxidative capacity, which have not been studied in reproduction. Therefore, this study aimed to investigate whether the anti-oxidative function of FF-HDL is associated with fertility outcomes. From 253 women undergoing modified natural cycle (MNC)- IVF at a single academic centre FF and plasma were collected (n = 375 cycles). Anti-oxidative function of FF was mainly attributable to HDL (n = 8; 83%). FF-HDL had a higher anti-oxidative function than plasma HDL (n = 19, P < 0.001) coinciding with increased vitamin E and sphingosine 1 phosphate content (P = 0.028 each). Proteomic analysis indicated no significant differences in major anti-oxidative proteins such as paraoxonase 1, apolipoprotein (apo) A-I or apoA-IV between FF-HDL and matched plasma-HDL (n = 5), while apoC-III, apoE and apoC-II were relatively lower in FF-HDL. Finally, FF-HDL anti-oxidative function was related to a decrease in the odds of the oocyte undergoing normal fertilization, an association that persisted after adjustment for confounders (odds ratio 0.97 (0.93–1), P = 0.041). In conclusion, FF-HDL has considerable anti-oxidative properties that might be relevant for embryo quality.
Apolipoprotein B-48 and late graft failure in kidney transplant recipients
Introduction Transplant vasculopathy resembles atherosclerotic plaque formation and is a major contributor to late graft failure in kidney transplant recipients (KTR). Remnant lipoproteins and associated triglycerides are causal risk factors for atherosclerotic plaques and have been implicated in late kidney graft failure. However, whether remnants derived from liver (containing apolipoprotein [apo] B100) or intestine (containing apoB48) are clinically more important is unclear. The current study investigated the association between baseline fasting apoB48 levels and late kidney graft failure. Methods 481 KTR with a functioning graft for at least 1 year were included in this retrospective, observational longitudinal single center cohort study. The primary endpoint was death-censored late graft failure, defined as need for initiation of dialysis or re-transplantation. ApoB48 was measured by enzyme-linked immunosorbent assay. Results During a median follow-up of 9.5 years, 61 KTR developed graft failure (12.7%). At baseline, KTR with higher apoB48 levels had lower eGFR (P < .001), lower high-density lipoprotein (HDL) cholesterol (P < .001), increased triglycerides (P < .001) and used cyclosporine more frequently (P = .003). Cox regression showed that higher baseline apoB48 was associated with higher risk of late graft failure [hazard ratio (95% confidence interval), 1.59 (1.22, 2.07), P < .001], independent of stepwise adjustment for potential confounders, including age and sex, immunosuppression type and proteinuria, triglycerides, and waist circumference (fully adjusted HR, 1.78 (1.29, 2.47), P < .001]. Conclusion ApoB48 is strongly associated with late graft failure, independent of potential confounders. Since apoB48-containing lipoproteins originate from the intestine, this study provides a rationale for considering pharmacological interventions targeting lipid absorption to improve graft outcome.
High density lipoprotein (HDL) particles from end-stage renal disease patients are defective in promoting reverse cholesterol transport
Atherosclerotic cardiovascular disease (CVD) represents the largest cause of mortality in end-stage renal disease (ESRD). CVD in ESRD is not explained by classical CVD risk factors such as HDL cholesterol mass levels making functional alterations of lipoproteins conceivable. HDL functions in atheroprotection by promoting reverse cholesterol transport (RCT), comprising cholesterol efflux from macrophage foam cells, uptake into hepatocytes and final excretion into the feces. ESRD-HDL (n = 15) were compared to healthy control HDL (n = 15) for their capacity to promote in vitro (i) cholesterol efflux from THP-1 macrophage foam cells and (ii) SR-BI-mediated selective uptake into ldla[SR-BI] cells as well as (iii) in vivo RCT. Compared with HDL from controls, ESRD-HDL displayed a significant reduction in mediating cholesterol efflux (p < 0.001) and SR-BI-mediated selective uptake (p < 0.01), two key steps in RCT. Consistently, also the in vivo capacity of ESRD-HDL to promote RCT when infused into wild-type mice was significantly impaired (p < 0.01). In vitro oxidation of HDL from healthy controls with hypochloric acid was able to fully mimic the impaired biological activities of ESRD-HDL. In conclusion, we demonstrate that HDL from ESRD patients is dysfunctional in key steps as well as overall RCT, likely due to oxidative modification.
Follicle-stimulating hormone stimulates free radical generation without inducing substantial oxidative stress in human granulosa cells
Does FSH induce free radical generation with substantial oxidative damage in human cumulus granulosa cells (cGCs) and mural granulosa cells (mGCs)? FSH of both physiological and supraphysiological concentrations induced free radical generation on subcellular levels, most notably in the mitochondria, while the elevated free radical load caused neglectable oxidative damage in both cGCs and mGCs. FSH is fundamental for regulation of granulosa cell (GC) function and oocyte maturation, during which a physiological level of reactive oxygen species (ROS) is essential, while excessive amounts lead to oxidative damage. Potential adverse effects of high FSH doses on GCs may be mediated by ROS. This prospective experimental study included patients who attended a reproductive medicine center in 2023. cGC and mGC were separately isolated and brought into culture on the day of oocyte retrieval, 36 h after ovulation induction with recombinant hCG (250 mg). Recombinant FSH, at different concentrations, mimicking physiological (6 mIU/ml) and supraphysiological (60 and 600 mIU/ml) conditions, was applied (n = 4 in each group). Women aged 20-35 years, undergoing ICSI with at least three follicles, were included. Quantum sensing of cGC and mGC free radicals, detected by either cytoplasm-located fluorescent nanodiamonds (FNDs) or mitochondria-targeted FNDs, was tracked for 2 h following FSH treatment in a magnetometry setup. Mitochondrial function analysis, as well as oxidative damage to DNA/RNA, lipids, and proteins, upon FSH exposure, was examined. FSH-induced cytoplasmic and mitochondrial ROS increases in cGC and mGC (  < 0.01 in all concentrations after 2 h) while showing different patterns along time: cGC showed significantly larger cytoplasmic ROS change compared with mGC to physiological (  < 0.01) and supraphysiological (  < 0.05) concentrations of FSH. Significantly larger free radical changes were observed in the mitochondria compared to the cytoplasm in response to FSH (all concentrations in cGCs with  < 0.05; supraphysiological concentrations in mGCs with  < 0.05,  < 0.001, respectively) after 2 h. Mitochondrial basal respiration and ATP production were significantly increased upon FSH exposure to supraphysiological concentrations in both cGCs (  < 0.01) and mGCs (  < 0.05). However, no oxidative damage to GC DNA/RNA, proteins, or lipids was found upon FSH exposure at any concentration except elevated lipid peroxidation in the FSH group of 600 mIU/ml (  < 0.05). N/A. The GCs came from females of different biological backgrounds and were stimulated before oocyte and GC retrieval, thereby increasing the risk of variation. In addition, the effects of long-term FSH exposure as well as the effects of the FSH-induced ROS on the oocyte remain to be investigated. We demonstrate that FSH of both physiological and supraphysiological concentrations induces free radical generation at subcellular levels, most notably in the mitochondria, while the elevated free radical load causes neglectable oxidative damage in both cGCs and mGCs. Our results suggest that the 'FSH Ootoxicity' hypothesis would not seem to be mediated by ROS in human GCs. This study is supported by the Abel Tasman Talent Program (ATTP) of the Graduate School of Medical Sciences of the University Medical Center Groningen/University of Groningen, The Netherlands, as well as an XS grant from NWO. Unrelated to the current work, A.H. is a member of an advisory board on the development and application of a lifestyle App for patients with infertility from Ferring Pharmaceutical Company, The Netherlands. R.S. is the founder of QT Sense B.V., who commercialize quantum sensing equipment. This article has no direct relation to the work of QT Sense B.V. The remaining authors have no conflicts of interest.