Hypertriglyceridemia and waist circumference linked to inflammation
MedWire News: Hypertriglyceridemic individuals with abdominal obesity tend to exhibit greater endothelial inflammation than healthy controls, study findings suggest.
Anthony Passerini (University of California, Davis, USA) and colleagues demonstrated that triglyceride-rich lipoprotein particles isolated after a meal (postprandial) modulated an inflammatory response in endothelial cells in proportion to an individual's postprandial triglyceride levels and visceral obesity.
Writing in the American Journal of Physiology, the researchers say: "Our findings link simple clinical metrics with biologically relevant markers of endothelial inflammation that may provide a means for assessing an individual's response to a repeated metabolic challenge, and an early measure of associated cardiovascular risk."
The study included 61 normal to hypertriglyceridemic (fasting triglycerides >150 mg/dl [1.69 mmol/l]) individuals, who represented broad ranges of body mass index (BMI, 19.8-57.9 kg/m2), waist circumference (0.64-1.32 m), and fasting serum triglycerides (41-538 mg/dl [0.46-6.08 mmol/l]).
The researchers conditioned cultured human aortic endothelial cells with postprandial triglyceride-rich lipoprotein particles (collected from the participants and isolated following a moderately high-fat meal) either alone, or simultaneously with the inflammatory cytokine tumor necrosis factor (TNF)-α, and then measured inflammatory responses using a lab-on-a-chip assay.
Fluorescent labeling revealed that postprandial triglyceride-rich lipoprotein particles were rapidly bound by endothelial cells via a low-density lipoprotein receptor-specific mechanism.
Passerini et al found that the particles did not induce an inflammatory response alone. However, in the presence of TNFα, internalization of triglyceride-rich lipoproteins increased by 15%, and expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin increased by 9.6%, 13.4%, and 13.2%, respectively - indicating inflammation activation.
Furthermore, transcription and expression of VCAM-1, but not ICAM-1 and E-selectin, varied in direct proportion to an individual's serum triglyceride levels and waist circumference.
On average, VCAM-1 expression was increased by 17.8% and 16.7% among patients with postprandial triglyceride levels above 225 mg/dl (2.54 mmol/l) and a waist circumference greater than 0.8 m, compared with patients with lower measures.
Commenting on their findings, Passerini et al say the results "link common epidemiological measurements of cardio-metabolic risk directly with acute markers of endothelial inflammation."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Nikki Withers