title: Erythrocyte hyperaggregation in obesity: determining factors and weight loss influence.
abstract: OBJECTIVE
  To compare erythrocyte aggregation (EA) in patients with severe obesity without other cardiovascular risk factors with a control group, using the Myrenne and the Sefam aggregometers, and to evaluate the effect of weight loss on this parameter.
  
  
  METHODS
  This was a longitudinal, clinical intervention study of a very low-calorie diet for 4 weeks followed by a low-calorie diet for 2 months. In 67 severely obese patients, an anthropometric and analytical evaluation [plasmatic lipids, fibrinogen (Fbg), and EA] was performed at baseline and 3 months after diet. The same determinations were performed in 67 normal-weight volunteers. EA was measured with the Myrenne MA1, which determines EA at stasis (EA0) and at a low shear of 3 seconds(-1) (EA1), and the Sefam aggregometer, which determines aggregation index at 10 seconds(-1) (IA10), aggregation time (Ta), and disaggregation threshold (gammaD). Insulin resistance (IR) was calculated by homeostasis model assessment.
  
  
  RESULTS
  Obese patients showed higher Fbg levels, EA0, EA1, IA10, and gammaD values, and lower Ta values. Differences between obese patients and control group for EA0, EA1, Ta, IA10, and gammaD disappeared after adjusting for BMI or for homeostasis model assessment but were maintained after adjusting for Fbg or low-density lipoprotein-cholesterol. Obese patients with IR showed higher EA0 and EA1 values. After weight loss, EA1 showed a significant improvement.
  
  
  CONCLUSIONS
  Obese patients show increased EA. Erythrocyte hyperaggregation does not seem to be related to a high Fbg level or to an abnormal lipid profile but to IR. Hyperagreggation improves after weight loss.
authors: Endocrinology Department, Doctor Peset University Hospital, Avda. Gaspar Aguilar 90, 46017 Valencia, Spain. solaeva@yahoo.es
authors: Eva
authors: E
authors: Solá
authors: Amparo
authors: A
authors: Vayá
authors: Dolores
authors: D
authors: Corella
authors: Maria-Luisa
authors: ML
authors: Santaolaria
authors: Francisco
authors: F
authors: España
authors: Amparo
authors: A
authors: Estellés
authors: Antonio
authors: A
authors: Hernández-Mijares
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D004903:Erythrocyte Aggregation / Q000502:physiology*; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D018709:Statistics, Nonparametric; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D014280:Triglycerides; D005340:Fibrinogen; D002097:C-Reactive Protein; D002784:Cholesterol