title: Platelet aggregation in obese and diabetic subjects: association with leptin level.
abstract: To clarify the relationship between serum leptin concentration and platelet aggregation mechanism, we investigated serum leptin concentration and agonist-induced platelet aggregation in eight obese subjects and eight non-obese and non-diabetic controls. In addition we also measured them in 15 type 2 diabetic subjects and 17 control subjects. Maximum platelets aggregation rate (MPAR) in control and diabetic subjects by adenosine diphosphate (ADP), collagen and thrombin were measured by aggregometer after pretreatment with 100 ng/ml leptin for 60 min. The MPAR by 0.15 U/ml thrombin stimulation in leptin-treated platelet in the controls was significantly increased compared with that in non-treated platelets, but not by ADP and collagen stimulation. Despite a significantly higher concentration of leptin in obese subjects, agonist-induced platelet aggregation in obese subjects was not different from that in controls. There were no significant differences in serum leptin concentration and MPAR by various agonists between diabetic and control subjects. When MPAR by ADP in the diabetic subjects was divided into two groups (high group: >50%, low group: <50%), the serum leptin concentration in the high group was significantly increased, compared with that in the low group. These results suggest that ADP-induced platelet aggregation may be associated with serum leptin concentration in diabetic subjects, and that leptin-associated platelet aggregation may affect the development of cardiovascular complications in obese and diabetic subjects.
authors: Departments of General Internal Medicine, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan.
authors: Chiyo
authors: C
authors: Sugiyama
authors: Masayoshi
authors: M
authors: Ishizawa
authors: Kazuo
authors: K
authors: Kajita
authors: Hiroyuki
authors: H
authors: Morita
authors: Yoshihiro
authors: Y
authors: Uno
authors: Kenji
authors: K
authors: Matsubara
authors: Masami
authors: M
authors: Matsumoto
authors: Takahide
authors: T
authors: Ikeda
authors: Tatsuo
authors: T
authors: Ishizuka
mesh_terms: D000244:Adenosine Diphosphate / Q000502:physiology; D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D010974:Platelet Aggregation / Q000502:physiology*; D013917:Thrombin / Q000502:physiology
chemical_list: D020738:Leptin; D000244:Adenosine Diphosphate; D013917:Thrombin