title: Effect of L-carnitine on acetyl-CoA content and activity of blood platelets in healthy and diabetic persons.
abstract: BACKGROUND
  Excessive blood platelet activity contributes to vascular complications in diabetic persons. Increased acetyl-CoA in platelets from diabetic persons has been suggested to be a cause of this hyperactivity. We therefore investigated whether L-carnitine, which up-regulates metabolism of acetyl-CoA in muscles and brain, may affect platelet function in healthy and diabetic individuals.
  
  
  METHODS
  We obtained platelets from healthy and diabetic persons and measured acetyl-CoA concentrations, malonyl dialdehyde (MDA) synthesis, and platelet aggregation in the absence and presence of L-carnitine. Activities of selected enzymes involved in glucose and acetyl-CoA metabolism were also assessed.
  
  
  RESULTS
  Fasting glucose, fructosamine, and hemoglobin A1c were present in significantly higher amounts in the blood of diabetic patients than in healthy individuals. Activities of carnitine acetyltransferase, glucose-6-phosphate dehydrogenase, oxoglutarate dehydrogenase, and fatty acid synthase were 17%-62% higher in platelets from diabetic patients. Mitochondrial acetyl-CoA was increased by 98% in platelets from diabetic patients, MDA synthesis was increased by 73%, and platelet aggregation by 60%. L-Carnitine had no or only a slight effect on these indices in platelets from healthy individuals, but in platelets from diabetic patients, L-carnitine caused a 99% increase in acetyl-CoA in the cytoplasmic compartment along with increases in MDA synthesis and platelet aggregation.
  
  
  CONCLUSIONS
  Excessive platelet activity in persons with diabetes may result from increased acetyl-CoA, which apparently increases synthesis of lipid activators of platelet function. L-Carnitine may aggravate platelet hyperactivity in diabetic persons by increasing the provision of surplus acetyl-CoA to the cytoplasmic compartment.
authors: Chair of Clinical Biochemistry, Departments of Laboratory Medicine and Molecular Medicine, Medical University of Gdańsk, Gdańsk, Poland.
authors: Anna
authors: A
authors: Michno
authors: Anna
authors: A
authors: Raszeja-Specht
authors: Agnieszka
authors: A
authors: Jankowska-Kulawy
authors: Tadeusz
authors: T
authors: Pawelczyk
authors: Andrzej
authors: A
authors: Szutowicz
mesh_terms: D000105:Acetyl Coenzyme A / Q000097:blood*; D000328:Adult; D001792:Blood Platelets / Q000378:metabolism* / Q000648:ultrastructure; D002331:Carnitine / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D010974:Platelet Aggregation; D012016:Reference Values
chemical_list: D008315:Malondialdehyde; D000105:Acetyl Coenzyme A; D002331:Carnitine