Metformin decreases platelet superoxide anion production in diabetic patients.
BACKGROUND
Patients with type 2 diabetes mellitus are usually treated with oral antidiabetic agents but it is still not known whether these drugs have antioxidant effects in humans.


METHODS
We studied 60 patients with type 2 diabetes mellitus, divided into three groups on the basis of hypoglycaemic treatment (Group A: metformin, Group B: glibenclamide, Group C: diet). All patients were followed for at least 1 year. The three subgroups had similar clinical characteristics. Twenty healthy subjects, of comparable sex and age, were enrolled as controls. In each subject, platelet production of superoxide anion (O(2)(-)) elicited by collagen, was determined by lucigenin assay.


RESULTS
Patients with diabetes had higher platelet O(2)(-) production than controls; no correlation was observed between blood glucose and platelet O(2)(-) production. Group A patients had platelet O(2)(-) production similar to that of healthy subjects but lower than Group B and Group C patients.


CONCLUSIONS
The present findings suggest an in vivo antioxidant activity of metformin and warrant prospective studies to further explore this hypothesis.
Gargiulo
P
P
Department of Endocrinology, University of Rome La Sapienza, Rome, Italy.
Caccese
D
D
Pignatelli
P
P
Brufani
C
C
De Vito
F
F
Marino
R
R
Lauro
R
R
Violi
F
F
Di Mario
U
U
Sanguigni
V
V
D000975:Antioxidants / Q000627:therapeutic use; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D005260:Female; D005905:Glyburide / Q000627:therapeutic use; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D012016:Reference Values; D013481:Superoxides / Q000037:antagonists & inhibitors / Q000097:blood*
D000975:Antioxidants; D007004:Hypoglycemic Agents; D013481:Superoxides; D008687:Metformin; D005905:Glyburide