title: Plasma complement C3 levels are associated with insulin secretion independently of adiposity measures in non-diabetic individuals.
abstract: OBJECTIVE
  To evaluate if complement C3 is associated with insulin secretion, as suggested by recent in vitro studies, independently of confounders including adiposity measures.
  
  
  RESULTS
  1010 nondiabetic subjects were stratified into quartiles according to complement C3 values. Insulin secretion was assessed using indexes derived from oral glucose tolerance test (OGTT) in the whole study group and from intravenous glucose tolerance test (IVGTT) in a subgroup (n = 110). Significant differences between quartiles of C3 were observed in body mass index (BMI), waist, fat mass, blood pressure, total cholesterol, high density lipoprotein (HDL), triglycerides, fasting and 2-h post-load glucose, fasting insulin, C reactive protein (hsCRP), fibrinogen, aspartate aminotransferase (AST), alanine aminotransferase (ALT), complement C4, and insulin sensitivity with C3 quartiles exhibiting graded increases in cardio-metabolic risk factors. Differences in insulin secretion indexes between C3 quartiles remained significant after adjustment for age, gender, BMI, insulin sensitivity, blood pressure, total cholesterol, HDL, triglycerides, hsCRP, fibrinogen, and complement C4 levels (P < 0.0001). A multivariable regression analysis revealed that complement C3 is a contributor of insulin secretion, explaining 2.4% and 1.9% of variation of the Stumvoll index for first-phase and second-phase insulin secretion, respectively, and 2.1% of variation of the InsAUC30/GluAUC30 index, independently of gender, age, BMI, waist, fat mass, blood pressure, total cholesterol, HDL, triglycerides, hsCRP, fibrinogen, AST, ALT.
  
  
  CONCLUSIONS
  Complement C3 concentrations are associated with insulin secretion independently of important determinants of glucose homeostasis such as gender, age, adiposity, subclinical inflammation, and insulin sensitivity.
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy.
authors: T V
authors: TV
authors: Fiorentino
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy.
authors: M L
authors: ML
authors: Hribal
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy.
authors: F
authors: F
authors: Andreozzi
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy.
authors: M
authors: M
authors: Perticone
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy.
authors: A
authors: A
authors: Sciacqua
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy.
authors: F
authors: F
authors: Perticone
authors: Department of Medical and Surgical Sciences, Viale Europa, University Magna-Græcia of Catanzaro, 88100 Catanzaro, Italy. Electronic address: sesti@unicz.it.
authors: G
authors: G
authors: Sesti
mesh_terms: D050154:Adiposity; D000328:Adult; D015992:Body Mass Index; D003176:Complement C3 / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis; D003430:Cross-Sectional Studies; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D007558:Italy / Q000453:epidemiology; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology / Q000209:etiology; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D050177:Overweight / Q000097:blood* / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D012307:Risk Factors; D055105:Waist Circumference
chemical_list: C038245:C3 protein, human; D003176:Complement C3; D003181:Complement C4; D007328:Insulin
keywords: Complement C3; Complement system; Glucose homeostasis; Insulin secretion; Subclinical inflammation