Background Angiotensin-converting enzyme (ACE) inhibitors are the drugs of choice for the treatment of hypertension in patients with non-diabetic nephropathies. However, not every trial has reported better results with ACE inhibitors (ACE-I) than with other drugs. This study investigates whether the acute and chronic effects of ACE inhibition on renal and glomerular haemodynamics are similar in glomerular and interstitial nephropathies.
Methods We studied 20 hypertensive patients, on their usual diet, with mild-to-moderate chronic renal failure secondary to non-diabetic nephropathy. After a three-week wash out period, we determined plasma clearances of para-amino-hippurate and inulin before, and after acute oral administration of either enalapril or ramipril. This same test was carried out after one and two years of treatment with the same drug.
Results Acute ACE inhibition causes a decrease of renal perfusion, glomerular filtration and pressure with an increase of afferent resistances. Long-term ACE inhibition is associated only with a decrease in renal perfusion, with a non-significant tendency to higher filtration fraction and lower afferent resistances. All the renal haemodynamic modifications mentioned above are present only in patients with glomerular diseases.
Conclusions Renal and glomerular haemodynamic responses are not similar after acute and chronic ACE inhibition. Only patients with glomerular diseases show acute or long-term responses to ACE inhibition.
Weidmann P., Boehlen LM, de Courten M.Effects of different antihypertensive drugs on human diabetic proteinuria . Nephrol Dial Transplant1993;8:582-4.
2.
Gansevoort RT , de Zeeuw D., de Jong PELong-term benefits of the antiproteinuric effect of angiotensin-converting enzyme inhibition in nondiabetic renal disease . Am J Kidney Dis1993;22:202-6.
3.
ter Wee PM, Epstein M.Angiotensin-converting enzyme inhibitors and progression of nondiabetic chronic renal disease. Arch Int Med1993;153:1749-59.
4.
The GISEN Group.Randomized placebo-controlled trial of effect of ramipril on decline in glomerular filtration rate and risk of terminal renal failure in proteinuric, non-diabetic nephropathy . Lancet1997;349:1857-63.
5.
Maschio G., Alberti D., Janin G. et al. Effect of the angiotensin-converting-enzyme inhibitor benazepril on the progression of chronic renal insufficiency. N Engl J Med1996; 334:939-45.
6.
Gomez DMEvaluation of renal resistances, with special reference to changes in essential hypertension. J Clin Invest1951 ;30:1143-55.
7.
Minetti EE, Cozzi MG, Biella E., Guidi E.Evaluation of a short protocol for the determination of para-aminohippurate and inulin plasma clearances. J Nephrol1994 ;7:342-6.
8.
Cozzi MG, Guidi E.Methodological problems in the simultaneous determination of p-aminohippurate and inulin in water and plasma: Is it safe to stock samples for the future determinations and use standard curves for one substance when both are present in the patient's plasma?Nephron1990;55:223-4.
9.
Guidi E., Cozzi MG, Minetti EE, Civati G., Busnach G., Brando B.Effect of familial hypertension on glomerular haemodynamics and tubulo-glomerular feedback after urinephrectomy. Am J Hypertens2001;14:121-8.
10.
Hall JE, Brands MWThe renin-angiotensin-aldosterone systems: renal mechanisms and circulatory homeostasis. In: Seldin DW and Giebisch G (eds.). The Kidney, Physiology and Pathophysiology. 3rd edition. Lippincott Williams & Wilkins, Philadelphia , 2000;1009-45.
