title: Low plasma adiponectin levels are associated with increased hepatic lipase activity in vivo.
abstract: OBJECTIVE
  Hepatic lipase plays a key role in hydrolyzing triglycerides and phospholipids present in circulating plasma lipoproteins. Plasma hepatic lipase activity is known to be regulated by several hormonal and metabolic factors, but hepatic lipase responsiveness to insulin is still controversial. Hypoadiponectinemia is known to be associated with insulin resistance, diabetes, and obesity. These conditions are often characterized by high plasma triglyceride and low HDL cholesterol levels, and they have been shown to be associated with high plasma hepatic lipase activity. We therefore raised the question whether adiponectin may be associated with plasma hepatic lipase activity in vivo.
  
  
  METHODS
  We measured plasma adiponectin and postheparin hepatic lipase activity in 206 nondiabetic men and in a second group of 110 patients with type 2 diabetes. The correlation of these parameters with markers of insulin resistance and systemic inflammation was investigated.
  
  
  RESULTS
  In nondiabetic patients, adiponectin levels were significantly inversely correlated with plasma hepatic lipase activity (r = -0.4, P < 0.01). These results were confirmed in the group of patients with type 2 diabetes (r = -0.32, P = 0.004). Multivariate analysis revealed that adiponectin was the strongest factor influencing hepatic lipase activity. The association was independent of age, sex, BMI, plasma triglycerides, insulin, HDL cholesterol, and high-sensitivity C-reactive protein and accounted for approximately 10 and 12% of the variation in hepatic lipase activity in the two different patient cohorts, respectively.
  
  
  CONCLUSIONS
  These results demonstrate for the first time a significant inverse association between adiponectin and postheparin plasma hepatic lipase activity that is independent of other factors such as markers of insulin resistance or inflammation. Therefore, adiponectin, rather than insulin, may represent an important factor contributing to the regulation of hepatic lipase activity in both nondiabetic individuals and patients with type 2 diabetes. The effect of adiponectin on hepatic lipase activity may also help to explain the HDL cholesterol-elevating action of adiponectin.
authors.affiliation: Department of Medicine I (Endocrinology and Metabolism), Ruprecht-Karls-University of Heidelberg, Germany. schneider.jg@gmail.com
authors.forename: Jochen G
authors.initials: JG
authors.lastname: Schneider
authors.forename: Maximilian
authors.initials: M
authors.lastname: von Eynatten
authors.forename: Stephan
authors.initials: S
authors.lastname: Schiekofer
authors.forename: Peter P
authors.initials: PP
authors.lastname: Nawroth
authors.forename: Klaus A
authors.initials: KA
authors.lastname: Dugi
mesh_terms: D052242:Adiponectin; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000201:enzymology; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood*; D007700:Kinetics; D008049:Lipase / Q000097:blood*; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012016:Reference Values; D014280:Triglycerides / Q000097:blood
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D036341:Intercellular Signaling Peptides and Proteins; C504173:LIPC protein, human; D008055:Lipids; D014280:Triglycerides; D002097:C-Reactive Protein; D008049:Lipase