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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Angiotensin-converting enzyme (ACE) inhibitors act by lowering the level of angiotensin II. The therapeutic benefits of these drugs and their potential side-effects therefore result from suppression of the physiological effects of angiotensin II. It is rational to prescribe an ACE inhibitor when the renin-angiotensin system is activated, as in renin-dependent essential hypertension, malignant hypertension and hypertension associated with heart failure. The beneficial effects of ACE inhibitor must be weighed against the special risks of renovascular hypertension: risk of renal artery thrombosis in case of unilateral stenosis and risk of renal failure if the stenosis is bilateral or affects a solitary kidney. In some situations the renin-angiotensin system is not directly involved in hypertension but may play a local haemodynamic role, as in some cases of primary or diabetic nephropathy. In such case the ACE inhibitors are thought to exert a protective effect. ACE inhibitors were reputed to be less effective in the elderly than in younger patients, but we now know that they can be prescribed with equal success in both instances to reduce peripheral resistance and improve regional blood flow as well as arterial compliance. Finally, ACE inhibitors can be prescribed, albeit with limited effectiveness, when the renin-angiotensin system is not activated, as in low renin hypertension and idiopathic hyperaldosteronism due to adrenal hyperplasia. They are ineffective in case of Conn's adenoma and contra-indicated in pregnant women.
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PMID:[For which hypertensive patient should angiotensin-converting enzyme inhibitor be prescribed or forbidden?]. 129 38

The purpose of our review is to delineate the pathogenic steps linking arterial hypertension in diabetes to diabetic nephropathy. The results of recent studies suggest that arterial hypertension in diabetes might lay a decisive pathogenetic role in the evolution of diabetic nephropathy: the existence of a higher ratio of erythrocytic Na/Li counter-transport in nephropathic diabetics as well as higher pressure values in the parents of diabetics who develop nephropathy indicates that hypertension may be casually related to renal complications. Diabetes-associated hypertension involves the modification of two important pressure- regulation factors: 1. an alteration in extracellular volume and increased renal absorption of sodium which leads to an expanded pool; 2. increased cardiovascular reactivity to norepinephrine and angiotensin II, an effect which might be related to increased intracellular calcium. Hyperfiltration seems to be present at the onset of diabetes, and arterial hypertension increases the transglomerular pressure gradient which is thought to play an important role in the pathogenesis of kidney damage. Antihypertensive drugs such as ACE-inhibitors and calcium channel blockers tend to protect the regulation of renal function. This could be explained by the fact that ACE-inhibitors suppress the trophic effects of angiotensin II on the nephron, while calcium channel blockers might interfere with intracellular processes involved in cell hypertrophy that require the interaction of calcium ions. In the management of diabetes prevention of diabetic nephropathy requires early and careful correction of diabetes-associated hypertension. We discuss the major groups of antihypertensive drugs, their metabolic side-effects and intrarenal induced hemodynamic changes.
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PMID:[Diabetic nephropathy and arterial hypertension: the physiopathological aspects and antihypertensive treatment]. 145 55

The use of calcium-channel blockers (CCBs) to reduce proteinuria associated with nephropathy in patients with diabetes mellitus is discussed. Metabolically induced damage to the nephrons in diabetic nephropathy decreases the filtration rate and increases the glomerular plasma flow rate and transcapillary hydraulic pressure. Microalbuminuria, which is predictive of nephropathy in patients with insulin-dependent diabetes mellitus, is associated with the development of clinical proteinuria and increased mortality. Micro-albuminuria should be evaluated periodically in diabetic patients, and antihypertensive therapy should be initiated when proteinuria is present or blood pressure control is needed. CCBs lower blood pressure because they prevent the action of angiotensin II by blocking the entry of calcium into renal vascular smooth muscle. Some CCBs, such as diltiazem and nicardipine, decrease glomerular pressure by increasing efferent arteriolar dilation. Others, such as nifedipine, may dilate both the afferent and efferent arterioles, thus causing increased excretion of protein. Studies in patients with diabetic nephropathy have shown that individual CCBs vary in their effects on proteinuria; this variation is attributable to their different sites of action and different effects on intrarenal activity. The choice of a CCB or an angiotensin-converting-enzyme inhibitor should be based on concomitant disease states and adverse-effect profiles. For control of hypertension in patients with diabetic nephropathy, diltiazem should be considered initially. Nicardipine is effective for short-term use but has not been tested in long-term studies; it should be considered a reasonable alternative.
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PMID:Calcium-channel blockers for treatment of diabetic nephropathy. 179 22

The pathogenesis of diabetic nephropathy remains elusive. A role for renal prostaglandins in antagonizing the hormonal effects of renin-angiotensin II has been postulated as a putative factor leading to hyperfiltration in patients with Type 1 (insulin-dependent) diabetes mellitus. Our aim was to elucidate the effects of angiotensin II on kidney haemodynamics and on blood pressure in eight normal subjects, in nine normotensive, in nine hypertensive with normal sodium-lithium countertransport activity in erythrocytes, in seven hypertensive without and in eight hypertensive Type 1 diabetic patients with microalbuminuria and with high sodium-lithium countertransport activity in erythrocytes. Angiotensin II infusion (4 ng.kg-1.min-1 for 60 min) decreased the glomerular filtration rate to a greater extent in normal subjects (-20%), than in normotensive patients (-5% p less than 0.01), in hypertensive patients with normal sodium-lithium countertransport activity in erythrocytes (-8% p less than 0.01) in hypertensive patients with high sodium-lithium countertransport (-6% p less than 0.01) and in hypertensive microalbuminuric patients (-5% p less than 0.01) with Type 1 diabetes. The urinary excretion rate of vasodilatory prostaglandins was two-three fold higher in all patients than in normal subjects. Acute indomethacin treatment restored a normal response to angiotensin II infusion in normotensive patients, but did not change the renal haemodynamic response in normal subjects. With regard to hypertensive patients with and without microalbuminuria indomethacin treatment restored a normal response to angiotensin II in some but not all patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Impaired response to angiotensin II in type 1 (insulin-dependent) diabetes mellitus. Role of prostaglandins and sodium-lithium countertransport activity. 193 64

Angiotensin converting enzyme inhibitor therapy decreases the production of the vasoconstrictive angiotensin II and reduces the degradation of certain kinines of vasodilatator action. Of captopril, enalapril, and lysinopril marketed abroad, only captopril of shorter action is available in Hungary. Angiotensin converting enzyme inhibitors are new means for the therapy of hypertension and congestive heart failure. Captopril seems to be effective at an early stage of heart failure. It slows down or even inhibits the progression of heart failure. New aspects of therapy have been revealed. It may be successfully used in angina pectoris, for the prevention of reperfusion arrhythmias accompanying myocardial infarction, for the treatment of renoparenchimal renal diseases, diabetic nephropathy. The side-effects, interactions, and dosage of angiotensin converting enzyme inhibitors have also been discussed.
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PMID:Angiotensin converting enzyme inhibitor therapy. 194 79

Angiotensin carboxypeptidase (ACP) activity has been detected in urine samples from normal subjects and patients with hypertension and diabetes by determining the enzyme's ability to convert angiotensin I to des-Leu angiotensin I. Gel filtration chromatography of a concentrated urine sample indicated that about equal amounts of the enzyme exist as 100 kDa and 500 kDa molecular weight forms, respectively. This ACP activity co-eluted with activity that cleaved histidine from des-Leu angiotensin I to form angiotensin II and activity that cleaved tyrosine from benzyloxycarbonyl-glutamyl-tyrosine (ZGT). These results suggest that the urinary ACP activity is due to cathepsin A as we have reported previously for the porcine kidney enzyme. Analysis of sequential urine samples from a single individual over a 6-day period revealed as much as a 6-fold fluctuation in creatinine-normalized ACP activity. Of five male healthy adult subjects, the creatinine-normalized urinary ACP activity ranged from 1.7 to 3.7 mU/mL with a mean of 2.8 mU/mL. However, five male patients with renovascular hypertension had elevated levels of ACP activity with a mean of 11.6 mU/mL. Of five male patients with diabetic nephropathy, all had elevated ACP activity levels with a mean of 21.0 mU/mL. It is concluded that ACP activity in the urine is due to cathepsin A probably derived from kidney tissue, and that the release is increased in patients with kidney damage. We suggest that urinary ACP activity should be evaluated further for a possible relationship to renal hypertension and as a potentially early marker for diabetic nephropathy.
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PMID:Angiotensin carboxypeptidase activity in urine from normal subjects and patients with kidney damage. 201 86

This paper synthesizes the pathogenic steps of arterial hypertension in diabetes mellitus: hyperosmolarity due to the hyperglycemia and increased sodic tubular reabsorption accounting for the expansion of the extracellular volume with hypervolemia; abnormalities of the ionic membrane pumps leading to abnormal intracellular calcium distribution, thereby inducing an increased vascular tone; atypical vasomotor reactivity to cathecolamines; modifications of the renin-angiotension-aldosterone system. The pathophysiological derangements by which hypertension could induce nephropathy are examined: the vasodilatation which can be detected from the onset of diabetes, may be a determinant in the transmission of systemic hypertension to the glomerular microcirculation with resulting enhancement of the hydrostatic transglomerular pressure gradient (i.c. the major factor producing glomerular injury), glomerular plasmatic flow and filtration rate. The nephron hyperfiltration increases the movement of plasmatic proteins across the glomerular capillary wall with subsequent mesangial hyperactivity and sclerosis. Antihypertensive treatment in diabetes follows general guidelines and it should be instituted even in the case of microhypertension being facilitated in this setting the appearance of microalbuminuria i.e. the starting point of nephropathy. Even if experimental studies are to favor ACE inhibitors as the first-line drugs for abating glomerular hypertension by mitigation of the direct effect of angiotensin II on the efferent arteriolar tone, clinical observations suggest that, regardless of type of treatment, the normalization of systemic arterial pressure, by reversing glomerular hypertension may be effective in preventing diabetic nephropathy.
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PMID:[The pathogenesis of arterial hypertension in diabetes mellitus and its role in nephropathy]. 207 80

The purpose of this study was to measure components of the renin angiotensin system in patients with type 1 diabetes mellitus, with and without nephropathy, to study the renal sensitivity to angiotensin II in uncomplicated type 1 diabetes and to investigate the short and long-term renal effects of angiotensin II reduction with angiotensin converting enzyme inhibitors in patients with diabetic nephropathy. In patients with type 1 diabetes without complications, plasma renin activity, angiotensin II and aldosterone levels were normal. In patients with diabetic nephropathy, renin levels were elevated, probably partly as a result of diuretic treatment. However, renin levels were also elevated compared to patients with other renal diseases who had similar treatment and degree of azotemia. The renal sensitivity to angiotensin II was normal in patients with uncomplicated diabetes. The reduction in glomerular filtration rate and renal plasma flow and increases in filtration fraction during A II infusion were equal to those in healthy controls. Nine days' captopril treatment in 15 patients with diabetic nephropathy induced an increase in renal plasma flow and a decrease in filtration fraction. The glomerular filtration rate remained unchanged. During 8 weeks' randomised enalapril or metoprolol treatment in 40 patients with diabetic nephropathy, enalapril treatment reduced proteinuria to half the initial value. Metoprolol treatment had no effect on proteinuria. Furosemide was also used and the dosage was adjusted to give equally effective blood-pressure control in both groups. During long-term treatment with captopril in patients with diabetic nephropathy, the rate of decline in kidney function over time was reduced to one-fourth the initial value even though the blood pressure was only slightly reduced. The renin angiotensin system appears to be functionally intact in diabetes mellitus and interruption by ACE inhibition reduces proteinuria both by blood pressure reduction and by an effect independent of systemic blood pressure. Long-term treatment might protect kidney function in diabetic nephropathy to a greater extent than would be expected from the blood-pressure-lowering effect alone.
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PMID:The renin angiotensin system in diabetes mellitus. A physiological and therapeutic study. 219 80

Diabetic nephropathy is characterized by persistent albuminuria, a decline in glomerular filtration rate (GFR) and elevated blood pressure. About 40% of all insulin-dependent diabetic patients will develop nephropathy, thus increasing their morbidity and mortality. The effect of early aggressive antihypertensive treatment with metoprolol, frusemide or thiazide in insulin-dependent diabetic patients with nephropathy has shown a significant reduction in albuminuria and in the rate of decline in the GFR (from 0.94 to 0.29 and 0.10 ml/min per month over 72 months of antihypertensive treatment). The effect of angiotensin converting enzyme (ACE) inhibition on kidney function in diabetic nephropathy showed that the GFR is not dependent on angiotensin II (Ang II), and that ACE inhibition diminished albuminuria, probably by lowering glomerular hypertension. In conclusion, antihypertensive treatment with ACE inhibitors or beta-blockers combined with a diuretic protects kidney function and reduces albuminuria in diabetic nephropathy. Angiotensin converting enzyme inhibitors can be considered as first-line drugs for hypertensive patients with diabetic nephropathy.
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PMID:The effect of beta-blockade and angiotensin converting enzyme inhibition on kidney function in diabetic nephropathy. 257 61

Favourable results with the use of inhibitors of the angiotension I-converting enzyme in the therapy not only of high-renin but also normo-renin and low-renin hypertension revived interest in research in the area of the renin-angiotensin (RAS) system. The use of classical radioimmunological, radiohistochemical receptor studies as well as of recent methods of molecular biology and pathology revealed that for the regulation of blood pressure and the extracellular volume and pathogenesis of hypertension not only RAS components in systemic blood are important but also local tissue RAS with an autocrine and paracrine action at the site of its origin. Cerebral RAS participates in the central cardiovascular regulation, in the control of the salt and water intake, the secretion of antidiuretic hormone and ACTH. In the cardiovascular apparatus RAS is responsible not only for vasoconstriction but it acts also as a growth factor promoting the development of cardiac and vascular hypertrophy. In the kidneys RAS decides on the blood flow, its distribution, glomerular filtration. Its excessive stimulation may contribute in arterial hypertension, diabetic nephropathy and in residual nephrons during chronic renal failure, to the change from functional hyperfiltration to irreversible structural damage of the nephron. Inhibitors of the converting enzyme not only reduce the peripheral vascular resistance in arterial hypertension but influence also the tissue production of angiotensin II and thus the regression of cardiovascular hypertrophy and progression of renal damage.
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PMID:[Renaissance of the renin-angiotensin system in the pathogenesis and therapy of arterial hypertension]. 280 32


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