title: Investigation of the mechanism(s) involved in decreasing increased fibrinogen activity in hyperglycemic conditions using L-lysine supplementation.
abstract: BACKGROUND
  Fibrinogen is a plasma glycoprotein that participates in the hemostasis system. Its malfunction has been reported as a consequence of diabetic complications. In this study, the inhibitory effect of L-Lysine (Lys) on the nonenzymatic glycation of fibrinogen was investigated in both in vitro and in vivo conditions.
  
  
  METHODS
  Fibrinogen was incubated with glucose in the presence or absence of Lys. Then, its structure was studied by fluorescence spectroscopy, circular dichroism, and electrophoresis. The Clauss method was used to determine fibrinogen activity. In addition, one of the two groups of type 2 diabetic patients receiving ordinary treatment was additionally treated with Lys for 3 months. Fibrinogen activity and some other parameters were evaluated in their plasma.
  
  
  RESULTS
  The results indicated increases in the activity of glycated fibrinogen in both of the in vivo and in vitro experiments. Advanced glycation end products were increased by time, as shown using fluorometry in both the plasma of the diabetic patients and the incubation medium of protein with glucose. The circular dichroism spectra showed some changes in the fibrinogen secondary and tertiary structures after glycation. The electrophoretic mobility of the glycated fibrinogen changed and the cross-link formation between the fibrinogen subunits due to glycation was observed. Lys inhibited all of the mentioned fibrinogen changes both in the in vitro experiments and after its administration to the diabetic patients.
  
  
  CONCLUSIONS
  Lys, as an inhibitor of protein glycation, improved fibrinogen's structure and function, both in vitro and in vivo.
authors.affiliation: Department of Clinical Biochemistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Mirmiranpour
authors.forename: S Zahra
authors.initials: SZ
authors.lastname: Bathaie
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Khaghani
authors.forename: Manouchehr
authors.initials: M
authors.lastname: Nakhjavani
authors.forename: Abbas
authors.initials: A
authors.lastname: Kebriaeezadeh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy*; D019587:Dietary Supplements; D005260:Female; D005340:Fibrinogen / Q000032:analysis* / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000737:chemistry; D008239:Lysine / Q000008:administration & dosage* / Q000737:chemistry*; D008297:Male; D008875:Middle Aged; D011485:Protein Binding; D016896:Treatment Outcome
chemical_list: D007004:Hypoglycemic Agents; D005340:Fibrinogen; D005947:Glucose; D008239:Lysine