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Systemic hypertension and the renin-angiotensin system in diabetic vascular complications
1Department of Medicine, University of Southern California, School of Medicine, Los Angeles.
Insights
Antihypertensive treatment is vital for diabetic patients due to hypertension
Area of Science:
- Cardiovascular Medicine
- Endocrinology
- Nephrology
Background:
- Hypertension exacerbates vascular complications in diabetes, including nephropathy, retinopathy, atherosclerosis, and left ventricular hypertrophy.
- Altered endothelial-vascular smooth muscle interactions contribute to vasoconstriction and vascular remodeling in diabetic patients.
Purpose of the Study:
- To investigate the role of the renin-angiotensin system (RAS) in diabetic vascular complications.
- To explore the mechanisms behind the protective effects of angiotensin-converting enzyme (ACE) inhibitors in diabetic patients.
Main Methods:
- Review of animal and human studies on ACE inhibitors and their effects on diabetic complications.
- Analysis of potential factors contributing to the observed effects of ACE inhibitors, such as tissue RAS activity and altered sensitivity to angiotensin II.
Main Results:
- ACE inhibitors demonstrate protective effects against glomerulosclerosis, cardiac remodeling, and atherosclerosis in diabetic models.
- ACE inhibitors may offer renal protection beyond blood pressure reduction, suggesting direct effects on the glomerulus.
- Circulating RAS activity appears paradoxically low in diabetic patients, necessitating further investigation.
Conclusions:
- The renin-angiotensin system (RAS) is implicated in diabetic vascular complications.
- ACE inhibitors show promise in managing hypertension and its associated complications in diabetes mellitus.
- Further research is needed to elucidate the complex mechanisms of RAS in diabetes and optimize therapeutic strategies.
Abstract:
Antihypertensive treatment in the diabetic patient is a critical issue because hypertension has an impact on all of the vascular complications of diabetes, including nephropathy, retinopathy, atherosclerosis, and left ventricular hypertrophy. These complications are a consequence of altered endothelial-vascular smooth muscle interrelations that ultimately enhance vasoconstriction and alter the remodeling processes in the vascular wall. Several observations suggest that the renin-angiotensin system (RAS) may be an important contributor to these processes in diabetes mellitus. In both animal and human studies, angiotensin-converting enzyme (ACE) inhibitors have been demonstrated to slow the progression of glomerulosclerosis, prevent abnormal remodeling processes in the heart following injury, and slow the progression of atherosclerosis. In particular, ACE inhibitors appear to protect the kidney more than would be expected from simply the lowering of blood pressure and decreasing of intraglomerular pressure, possibly because angiotensin II has both hemodynamic and direct effects on the glomerulus. Paradoxically, however, the activity of the circulating RAS is low in diabetic patients. Part of these seemingly inconsistent observations may be due to (1) potential activity of tissue RASs, (2) increased sensitivity to angiotensin II in diabetes, or (3) an effect of ACE inhibition on other systems in addition to the RAS. Investigation of these mechanisms will be important in determining the therapeutic role of inhibition of the RAS in diabetes mellitus.