Cardiac and Renal Function are Progressively Impaired with Aging in Zucker Diabetic Fatty Type II Diabetic Rats
This study investigated the temporal relationship between cardiomyopathy and renal pathology in the type II diabetic Zucker diabetic fatty (ZDF) rat. We hypothesized that changes in renal function will precede the development of cardiac dysfunction in the ZDF rat. Animals (10 weeks old) were divided into four experimental groups: Lean Control (fa/?) LC (n = 7), untreated ZDF rats (n = 7) sacrificed at 16 weeks of age, and LC (n = 7) untreated ZDF rats (n = 9) sacrificed at 36 weeks of age. LV structural/functional parameters were assessed via Millar conductance catheter. Renal function was evaluated via markers of proteinuria and evidence of hydronephrosis. LV mass was significantly less in the ZDF groups at both time points compared to age-matched LC. End diastolic volume was increased by 16% at 16 weeks and by 37% at 36 weeks of age (p < 0.05 vs. LC). End diastolic pressure and end systolic volume were significantly increased (42% and 27% respectively) at 36 weeks of age in the ZDF compared to LC. Kidney weights were significantly increased at both 16 and 36 week in ZDF animals (p < 0.05 vs. LC). Increased urinary albumin and decreased urinary creatinine were paralleled by a marked progression in the severity of hydronephrosis from 16 to 36 weeks of age in the ZDF group. In summary, there is evidence of progressive structural and functional changes in both the heart and kidney, starting as early as 16 weeks, without evidence that one pathology precedes or causes the other in the ZDF model of type II diabetes.