BACKGROUND: The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is a new genetic model of non-insulin-dependent diabetes mellitus (NIDDM). We investigated whether angiotensin inhibition influences the onset of NIDDM and brings about a regression of renal injury in diabetes mellitus. METHODS AND RESULTS: Six-week-old OLETF rats were treated with the angiotensin-converting enzyme (ACE) inhibitors imidapril or enalapril for 16 weeks. Systolic blood pressure is increased in an age-dependent manner in OLETF rats. In this study, the elevation in systolic blood pressure was dose-dependently reduced by ACE inhibitor treatment. In OLETF rats, plasma concentrations of insulin and glucose increased and the glucosuria occurred at the age of 22 weeks. Simultaneously, OLETF rats exhibited proteinuria and nodular lesions in glomeruli. The ACE inhibitor treatment almost completely reduced glucosuria, and also decreased plasma concentrations of insulin and glucose in OLETF rats. ACE inhibitor treatment lessened the proteinuria and attenuated morphologically the severity of nodular lesions in OLETF rats. Moreover, increases in plasminogen activator inhibitor 1 (PAI-1) in OLETF rats were reduced by the ACE inhibitor treatment, and the improvement of glomerular lesions was related to decreases of PAI-1 and angiotensin II levels in plasma but not to improvement of glucose metabolism. CONCLUSIONS: ACE inhibitors delay onset of NIDDM with attenuation of kidney injury. The regression of kidney lesions is probably due to angiotensin reductions but not to glucose metabolism per se. ACE inhibitor drug therapy may be useful in preventing NIDDM and the subsequent renal injury in patients with NIDDM.
BACKGROUND: The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is a new genetic model of non-insulin-dependent diabetes mellitus (NIDDM). We investigated whether angiotensin inhibition influences the onset of NIDDM and brings about a regression of renal injury in diabetes mellitus. METHODS AND RESULTS: Six-week-old OLETFrats were treated with the angiotensin-converting enzyme (ACE) inhibitors imidapril or enalapril for 16 weeks. Systolic blood pressure is increased in an age-dependent manner in OLETFrats. In this study, the elevation in systolic blood pressure was dose-dependently reduced by ACE inhibitor treatment. In OLETFrats, plasma concentrations of insulin and glucose increased and the glucosuria occurred at the age of 22 weeks. Simultaneously, OLETFrats exhibited proteinuria and nodular lesions in glomeruli. The ACE inhibitor treatment almost completely reduced glucosuria, and also decreased plasma concentrations of insulin and glucose in OLETFrats. ACE inhibitor treatment lessened the proteinuria and attenuated morphologically the severity of nodular lesions in OLETFrats. Moreover, increases in plasminogen activator inhibitor 1 (PAI-1) in OLETFrats were reduced by the ACE inhibitor treatment, and the improvement of glomerular lesions was related to decreases of PAI-1 and angiotensin II levels in plasma but not to improvement of glucose metabolism. CONCLUSIONS:ACE inhibitors delay onset of NIDDM with attenuation of kidney injury. The regression of kidney lesions is probably due to angiotensin reductions but not to glucose metabolism per se. ACE inhibitor drug therapy may be useful in preventing NIDDM and the subsequent renal injury in patients with NIDDM.