title: Thromboxane production in morbidly obese subjects.
abstract: Postmortem studies have demonstrated that morbidly obese subjects, surprisingly, have less coronary atherosclerosis than obese subjects. However, the reasons for this apparent protection from atherosclerosis are not yet clear. Thromboxane A2, a marker of platelet activation, is greater in obese subjects than in lean subjects, and this might be a clue to their increased cardiovascular risk. However, data on thromboxane A2 in morbidly obese subjects are lacking; therefore, we hypothesized that lower levels of thromboxane A2 in morbidly obese subjects might play a role in their lower atherothrombotic burden. We measured the serum levels of thromboxane B2 (TxB2), a stable metabolite of thromboxane A2, high-sensitivity C-reactive protein (hs-CRP) and leptin in 17 lean subjects (body mass index [BMI] 22.9 ± 1.6 kg/m(2)), 25 obese subjects (BMI 32.6 ± 2.4 kg/m(2)), and 23 morbidly obese subjects (BMI 48.6 ± 7.1 kg/m(2)), without insulin resistance, diabetes, or overt cardiovascular disease. The serum TxB2 levels were lower in the lean subjects than in the obese subjects (p = 0.046) and in the morbidly obese subjects than in the lean and obese subjects (p = 0.015 and p <0.001, respectively). In contrast, the hs-CRP and leptin levels were greater in the obese than in the lean subjects (hs-CRP, p <0.001; leptin, p <0.001) and in the morbidly obese subjects than in the lean subjects (p <0.001 for both). Leptin was also higher in the morbidly obese subjects than in the obese subjects (p <0.001). TxB2 negatively correlated with leptin and BMI. hs-CRP correlated with leptin, and both also correlated with waist circumference, BMI, and homeostasis model assessment of insulin-resistance. In conclusion, insulin-sensitive morbidly obese subjects had lower levels of TxB2 than the obese subjects and lean subjects, suggesting that reduced platelet activation could play a role in the paradoxical protection of morbidly obese subjects from atherosclerosis, despite the greater levels of leptin.
authors: Institute of Cardiology, Catholic University, Rome, Italy.
authors: Francesca
authors: F
authors: Graziani
authors: Luigi M
authors: LM
authors: Biasucci
authors: Pio
authors: P
authors: Cialdella
authors: Giovanna
authors: G
authors: Liuzzo
authors: Simona
authors: S
authors: Giubilato
authors: Roberta
authors: R
authors: Della Bona
authors: Fabio M
authors: FM
authors: Pulcinelli
authors: Amerigo
authors: A
authors: Iaconelli
authors: Geltrude
authors: G
authors: Mingrone
authors: Filippo
authors: F
authors: Crea
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000097:blood*; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood*; D013928:Thromboxane A2 / Q000097:blood*; D013929:Thromboxane B2 / Q000097:blood*
chemical_list: D020738:Leptin; D013929:Thromboxane B2; D013928:Thromboxane A2; D002097:C-Reactive Protein