Genetic characerization of early renal changes in diabetes

Diabetic kidney disease (DKD) appears heritable, suggesting genetic factors influence disease susceptibility. In our study, genes were mapped mediating early renal hypertrophic in response to diabetes. A survey of murine strains (N=15) was conducted to identify variation in kidney hypertrophy following diabetes induction. Mice with greater FVB/N and less C57BL/6 renal hypertrophy were crossed and diabetic F2 generation mice (n=534) were characterised. To confirm loci responsible for the renal hypertrophic response, diabetic congenic mice were generated by backcrossing FVB/N mice that conferred greater or C57BL/6 conferring lower risk into the reciprocal strain mice. Kidney weights of (FVB/N x C57BL/6) F2 diabetic mice were broadly distributed. Quantitative trait locus (QTL) analysis revealed that diabetic mice with kidney weights in the upper quartile shared alleles on chromosomes 6 and 12, with the FVB/N allele on chromosome 6 conferring greater susceptibility. On chromosome 12, C57BL/6 homozygotes were more significantly represented (LOD=3.8) conferring less susceptibility. The diabetic B6.Drc1/2f congenic strain developed kidney damage, while the reciprocal congenic, with FVB.Drc1/2b strain were protected. Microarray analysis identified differentially expressed genes between diabetic C57BL/6 and FVB/N mice. QTL mapping for early renal responses to diabetes identified two loci syntenic with regions identified for human diabetic kidney disease. Providing a new resource to study DKD. Six kidneys were analysed per group and there are four groups. Of the four groups, two are diabetic and two are control. The control mice were saline injected and were urine or blood gluocse tested at the same time as the diabetic mice. All mice were 8 weeks of age and a mix of male and female. All samples were collected at the same time.