Vitamin K2 (Menaquinone-7) supplementation does not affect vitamin K-dependent coagulation factors activity in healthy individuals.

BACKGROUND: Vitamin K has long been regarded as a procoagulant drug by physicians, and concerns have been raised with regard to its effects on hemostasis. Although many studies have shown that vitamin K supplementation is safe for thrombotic events, the effect of vitamin K supplementation on the activities of vitamin K dependent procoagulation factors in healthy individuals is not available. OBJECTIVES: This study aimed to investigate whether vitamin K2 supplementation at recommended doses affects the activity of vitamin K dependent procoagulation factors in healthy individuals without any anticoagulation treatment. DESIGN: Forty healthy volunteers between 25 and 40 years of age were recruited. Menaquinone-7 (MK-7) was administrated at 90 µg for 30 days. Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and blood coagulation factors II, VII, IX, and X activities and Protein induced by vitamin K absence or antagonist-II (PIVKA-II) were measured on days 0 and 30 after MK-7 administration. RESULTS: PT, APTT, and TT showed no significant differences on day 30 when compared with baseline. The activities of coagulation factors II, VII, IX, and X on day 30 showed no significant differences with those at baseline. PIVKA-II levels were unchanged after 30 days of MK-7 supplementation. CONCLUSIONS: MK-7 supplementation at recommended dosage does not affect vitamin K-dependent coagulation factors' coagulation activity, and does not enhance the carboxylation of prothrombin in healthy individuals. This indicated that MK-7 administration does not alter hemostatic balance in healthy populations without anticoagulation treatment.

l-arginine minimizes immunosuppression and prothrombin time and enhances the genotoxicity of 5-fluorouracil in rats.

OBJECTIVE: The aim of this study was to evaluate the effect of low doses of l-arginine supplementation on hemogram, integrity of DNA and spleen, inflammatory infiltrate in the jejunum, and in the coagulogram of rats submitted to 5-fluorouracil (5-FU) chemotherapy. METHODS: Thirty-two Wistar rats were fed commercial feed and water ad libitum and grouped into four (eight rats per group): The control group was given a 0.9% physiologic solution to simulate the application of 5-FU in the other groups; the G5-FU group was given a dose of 5-FU; the GArg50 and GArg100 groups were given a dose of 5-FU and supplemented with 50 and 100 mg l-arginine/d added in the drinking water ad libitum. RESULTS: The rats in the GArg50 group did not lose weight after chemotherapy. GArg50 rats presented polycythemia owing to dehydration caused by diarrhea generated by 5-FU. GArg100 rats had increased total leukocyte count, eosinophils, lymphocytes, and index in the total index of DNA damage, yet showed a reduction in prothrombin time and in the spleen depletion index. Rats in the G5-FU, GArg50, and GArg100 groups had similar moderate inflammatory infiltrate in the jejunum. CONCLUSION: Supplementation with 100 mg/d of l-arginine minimized immunosuppression, spleen depletion, and prothrombin time and contributed to the breakdown of 5-FU-generated DNA in Wistar rats. Supplementation with 50 mg/d of l-arginine decreased the weight loss generated by 5-FU in Wistar rats. Supplements with 50 or 100 mg of l-arginine did not interfere with 5-FU-generated jejunal inflammatory infiltrate.