Lipoprotein Lipase Expression in Livers of Morbidly Obese Patients Could be Responsible for Liver Steatosis
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Most patients with morbid obesity develop non-alcoholic fatty liver disease (NAFLD). The origins of lipid deposition in the liver and the effects of bariatric surgery in the obese with NAFLD are controversial.
We analyzed lipids and lipoprotein lipase (LPL) in both plasma and liver biopsies performed before and 12–18 months after Roux-en-Y gastric bypass surgery in 26 patients.
In the livers of morbidly obese patients, the levels of LPL messenger RNA (mRNA) were higher (4.5-fold) before surgery than afterwards than control livers. In these patients, LPL activity was also significantly higher (91 ± 7 mU/g) than in controls (51 ± 3 mU/g, p = 0.0026) and correlated with the severity of the liver damage. All hepatic lipids were significantly increased in obese patients; however, after bariatric surgery, these lipids, with the exception of NEFA, tended to recover to normal levels.
The liver of obese patients presented higher LPL activity than controls, and unlike the controls, this enzyme could be synthesized in the liver because it also present LPL mRNA. The presence of the LPL activity could enable the liver to capture circulating triacylglycerides, thus favoring the typical steatosis observed in these patients.
KeywordsMetabolic syndrome Hepatic steatosis NAFLD NASH LPL
non-alcoholic fatty liver disease
free fatty acids
homeostasis model assessment of insulin resistance
We are indebted to Drs. J. A. Baena, J. M. Fort, R. Catalán, R. Galard, A. Lecube, H. Allende, and V. Vargas for their outstanding work with subjects in the hospital and for their important contribution to this research. The authors thank Dr. J. D. Brunzell (University of Washington, Seattle, WA, USA) for providing 5D2 antibody. The authors have declared that no conflict of interest exists. The authors who have taken part in this study do not have a relationship with the manufacturers of the drugs involved either in the past or present and did not receive funding from the manufacturers to carry out their research. English grammar and language had been corrected by American Journal Experts (www.journalexperts.com). This research has received funding from the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III of the Spanish Ministry for Health and Consumer Affairs (PI030042, PI030024 and PI070079).
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