Génétique des complications du diabète : rétinopathie

Endothelial nitric oxide synthase genotype and haplotype are not associated with diabetic retinopathy in diabetes type 2 patients

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene have been associated with the development of diabetic retinopathy (DR) in patients with type 1 diabetes mellitus (T1DM), but not with T2DM. However, no previous study has analyzed combinations of genetic markers (haplotypes), which can be more informative. We studied three eNOS genetic polymorphisms: a single nucleotide polymorphism in the promoter region (T(-786)C), in exon 7 (Glu298Asp), and a variable number of tandem repeats in intron 4 (b/a) in 103 healthy controls, and in 170 patients with T2DM (without DR, N=114; with DR, N=56). We also examined the association of eNOS gene haplotypes with T2DM and with DR. No differences were found in the frequencies of genotypes and alleles of the three polymorphisms among the three groups of subjects. However, the "C-Glu-b" haplotype was more common in healthy controls (24%) than in T2DM patients (7%) (P=0.0001). Finally, no significant difference in the distribution of eNOS haplotypes frequencies was found when T2DM patients with or without DR were compared (P=0.7372). These findings suggest no association between DR and individual eNOS haplotypes in T2DM patients. The "C-Glu-b" haplotype, however, may have a protective effect against T2DM. Further studies should be conducted to address the molecular basis for such an effect.

Discovery of 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]indole-N-acetic acid (lidorestat) and congeners as highly potent and selective inhibitors of aldose reductase for treatment of chronic diabetic complications

Recent efforts to identify treatments for chronic diabetic complications have resulted in the discovery of a novel series of highly potent and selective 3-[(benzothiazol-2-yl)methyl]indole-N-alkanoic acid aldose reductase inhibitors. The lead candidate, 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]indole-N-acetic acid (lidorestat, 9) inhibits aldose reductase with an IC(50) of 5 nM, while being 5400 times less active against aldehyde reductase, a related enzyme involved in the detoxification of reactive aldehydes. It lowers nerve and lens sorbitol levels with ED(50)'s of 1.9 and 4.5 mg/kg/d po, respectively, in the 5-day STZ-induced diabetic rat model. In a 3-month diabetic intervention model (1 month of diabetes followed by 2 months of drug treatment at 5 mg/kg/d po), it normalizes polyols and reduces the motor nerve conduction velocity deficit by 59% relative to diabetic controls. It has a favorable pharmacokinetic profile (F, 82%; t(1/2), 5.6 h; Vd, 0.694 L/kg) with good drug penetration in target tissues (C(max) in sciatic nerve and eye are 2.36 and 1.45 mug equiv/g, respectively, when dosed with [(14)C]lidorestat at 10 mg/kg po).