Anorexia nervosa: A model for the investigation of platelet aggregation induced by heparin-like drugs?

The present study establishes that there is a relationship between the severity of weight loss, in patients with anorexia nervosa, and in vitro platelet responsiveness to therapeutic concentrations of conventional unfractionated heparin (UH). Platelets prepared from patients weighing less than 75% of the average body weight responded significantly more often and to a greater extent than those from patients with body weights 75-90% of the average body weight or from control subjects (body weight ± 10% of average body weight). Weight gain, over a period of 3-8 weeks, resulted in a loss of platelet responsiveness to UH. In contrast to UH, a low molecular weight heparinoid (LMWH), Org 10172, did not cause any significant aggregation responses in the same samples. The findings of the present study suggest that severe weight loss may be associated with increased platelet responsiveness to UH but not to LMWH. Furthermore, significant weight gain is associated with a loss of platelet responsiveness to UH. Platelets obtained from patients with severe weight loss due to anorexia nervosa may be a useful model for the assessment of platelet interactions with UH-like drugs. The observations reported here may account for complications related to UH therapy in patients with severe weight loss. Emaciation and weight loss should be considered as important variables in studies evaluating platelet function during UH therapy.