Effects of plasma homocysteine levels on serum HTase/PON activity in patients with type 2 diabetes.
BACKGROUND
Homocysteine is a predictor of vascular disease and may have an important role in diabetes. In this study, we examined the effects of folic acid and methylcobalamin supplementation on changes in homocysteine (Hcy) levels and homocysteine thiolactonase/paraoxonase (HTase/PON) activity in a short-term trial.


METHODS
Ninety patients with type 2 diabetes were randomly divided into three groups: Group I received no vitamin supplementation, group II received 5 mg/day folic acid (orally), group III received folic acid (5 mg/day) in combination with methylcobalamin (500 microg/day; intramuscularly, on prescription). All patients were treated for 2 weeks. Plasma Hcy, HTase/PON activity, vitamin B(12), and folic acid were measured before and after supplementation in each group. In addition, forty healthy (nondiabetic) controls were enrolled.


RESULTS
Serum HTase/PON activity was significantly higher in diabetics compared with controls, plasma Hcy levels were significantly lower (P<0.05). After vitamin supplementation there was a significant reduction in plasma Hcy levels. The mean percentage reduction in Hcy was 2.75% in group I, 14% in group II and 37.3% in group III. There was a significant inverse correlation between the changes in HTase/PON activity and Hcy levels (r=-0.29, P=0.004). A 2.72% increase in HTase/PON activity was seen in group I, an 8.03% increase was detected when folic acid was given in group II (P<0.001), and a 17.59% increase in HTase/PON activity was seen in group III (P<0.001).


CONCLUSIONS
Short-term oral folic acid (5 mg/day) supplementation with or without methylcobalamin appeared to be an effective approach to decrease Hcy levels and increase HTase/PON activity in patients with type 2 diabetes. A decrease in plasma Hcy levels may partly account for the elevation of serum HTase/PON activity. This could be a novel mechanism to protect against vascular diabetic complications.
Weijun
Gu
G
Department of Endocrinology, Chinese PLA General Hospital, Beijing, China.
Juming
Lu
L
Guoqing
Yang
Y
Jingtao
Dou
D
Qinghua
Guo
G
Yiming
Mu
M
Changyu
Pan
P
D000328:Adult; D000368:Aged; D043303:Aryldialkylphosphatase / Q000097:blood*; D002265:Carboxylic Ester Hydrolases / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000627:therapeutic use; D014815:Vitamins / Q000627:therapeutic use
D014815:Vitamins; D006710:Homocysteine; D005492:Folic Acid; C019476:mecobalamin; D002265:Carboxylic Ester Hydrolases; C502233:homocysteine-thiolactonase, human; D043303:Aryldialkylphosphatase; D014805:Vitamin B 12