title: Relation between plasma nitric oxide levels and diabetic retinopathy.
abstract: OBJECTIVE
  Nitric oxide (NO) plays an important role in homeostatic vasodilation and the regulation of blood flow. On the other hand, excess release of NO causes various vascular complications. There are only a few reports on the relationship between plasma NO levels and microvascular complications, especially diabetic retinopathy (DR) in patients with type 2 diabetes. The purpose of this study was to determine the relationship between plasma NO levels and DR.
  
  
  METHODS
  In a prospective study, blood samples were obtained from 36 patients with diabetes and no diabetic retinopathy (NDR), 43 patients with nonproliferative diabetic retinopathy (NPDR), 18 patients with proliferative diabetic retinopathy (PDR), and 40 subjects without diabetes mellitus, who served as controls. The levels of plasma NOx (nitrite and nitrate), the stable metabolites of NO, were measured by high-performance liquid chromatography with the Griess method.
  
  
  RESULTS
  The plasma NOx levels were 92.8 +/- 16.0, 70.2 +/- 6.8, 90.3 +/- 9.1, and 53.8 +/- 6.1 micromol/l in patients with NDR, NPDR, or PDR, and in the controls, respectively. The plasma NOx levels in the three diabetic groups were significantly higher than those in the control group (P < 0.05 in each case).
  
  
  CONCLUSIONS
  The increased plasma NO levels in patients with type 2 diabetes indicate that NO may be associated with the pathogenesis of DR.
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Izumi
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan. nagaoka@asahikawa-med.ac.jp.|Departments of Ophthalmology and Surgery, Scott & White Eye Institute, Texas A&M University Health Science Center, Temple, TX, USA. nagaoka@asahikawa-med.ac.jp.
authors.forename: Taiji
authors.initials: T
authors.lastname: Nagaoka
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Mori
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Sato
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.affiliation: Department of Ophthalmology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Yoshida
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D003930:Diabetic Retinopathy / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood*; D011379:Prognosis; D011446:Prospective Studies; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D009569:Nitric Oxide