PurposeThis study aimed to determine whether l-arginine supplementation lasting for 18 months maintained long-lasting effects on diabetes incidence, insulin secretion and sensitivity, oxidative stress, and endothelial function during 108 months among subjects at high risk of developing type 2 diabetes.MethodsOne hundred and forty-four middle-aged subjects with impaired glucose tolerance and metabolic syndrome were randomized in 2006 to an l-arginine supplementation (6.4 g orally/day) or placebo therapy lasting 18 months. This period was followed by a 90-month follow-up. The primary outcome was a diagnosis of diabetes during the 108 month study period. Secondary outcomes included changes in insulin secretion (proinsulin/c-peptide ratio), insulin sensitivity (IGI/HOMA-IR), oxidative stress (AOPPs), and vascular function. After the 18 month participation, subjects that were still free of diabetes and willing to continue their participation (104 subjects) were further followed until diabetes diagnosis, with a time span of about 9 years from baseline.ResultsAlthough results derived from the 18 month of the intervention study demonstrated no differences in the probability of becoming diabetics, at the end of the study, the cumulative incidence of diabetes was of 40.6% in the l-arginine group and of 57.4% in the placebo group. The adjusted HR for diabetes (l-arginine vs. placebo) was 0.66; 95% CI 0.48, 0.91; p < 0.02). Proinsulin/c-peptide ratio (p < 0.001), IGI/HOMA-IR (p < 0.01), and AOPP (p < 0.05) levels were ameliorated in l-arginine compared to placebo.ConclusionsThese results may suggest that the administration of l-arginine could delay the development of T2DM for a long period. This effect could be mediated, in some extent, by l-arginine-induced reduction in oxidative stress.

We report the case of a 20-yr-old girl with thiamine-responsive megaloblastic anemia (TRMA) associated with diabetes mellitus and bilateral sensorineural deafness (1, 2). Megaloblastic anemia was diagnosed at 7 months and was successfully treated with multiple vitamin preparations. Diabetes was diagnosed at age 2 yr and was treated with insulin for 6 months at a dose of 0.5 IU/kg BW. The diagnosis of TRMA syndrome was clinically confirmed when bilateral sensorineural deafness was detected. Thereafter, thiamine treatment was started (50 mg/day), and insulin was discontinued because of frequent episodes of hypoglycemia. At age 9 yr, due to reoccurrence of hyperglycemia, the patient underwent glibenclamide treatment (2.5 mg/day), which was replaced by insulin at menarche. Glycemic control was satisfactory, as evidenced by hemoglobin A 1c (HbA 1c ) values between 7.5-8%. Laboratory parameters, including coagulation factors, were in the normal range.

Primary objective was to evaluate whether an intensified insulin therapy (IIT) incorporating the target of normal fasting glucose and HbA1c levels could halve the incidence of restenosis/amputation/SCA/death at 6 months after peripheral angioplasty compared with standard care (SC) in patients with type 2 diabetes (DMT2) affected by critical limb ischemia (CLI). Forty-six consecutive patients with DMT2 and CLI were randomly assigned to a parallel, open-label study with IIT (basal-bolus glulisine + glargine administrations) or SC (glargine administration + oral antidiabetic drugs). A SNP of eNOS (rs753482-A>C) and circulating CD34(+) and CD34(+)KDR(+) progenitor cells were determined. At the end of the study, although HbA1c levels were lower in IIT than in SC (6.9 ± 1.3 % vs. 7.6 ± 1.2 %, p < 0.05), IIT did not reduce the cumulative incidence of restenosis/amputation/SCA/death (52 and 65 %, respectively, odd ratio 0.59; CI 95 %: 0.21-1.62, p = 0.59). rs753482AC+CC as compared with rs753482AA increased the cumulative incidence of restenosis/amputation/SCA/death (79 and 42 %; odd ratio 5.3; CI 95 %: 1.41-19.5, p < 0.02). Baseline CD34(+)KDR(+) were higher in rs753482AA (166.2 ± 154.0 × 10(6) events) than in rs753482AC+CC (63.1 ± 26.9 × 10(6) events, p < 0.01). At the end of the study, the highest circulating CD34(+)KDR(+) were found in IIT rs753482AA (246.9 ± 194.0 × 10(6) events) while the lowest levels were found in SC rs753482AC+CC (70.9 ± 45.0 × 10(6) events). IIT did not decrease the cumulative incidence of restenosis/amputation/SCA/death in DMT2 and CLI patients. These patients correspond to a class of fragile subjects at high risk of cardiovascular events, and new predictors of restenosis should be contemplated, such as of eNOS polymorphism, (rs753482-A>C SNP) and circulating endothelial progenitor cells.