[Left ventricular function in hypertension without left ventricular hypertrophy: echographic study with modelisation of left ventricular-aortic coupling]. / Performance et rendement du ventricule gauche chez l'hypertendu sans hypertrophie ventriculaire gauche : étude échographique par modélisation du couplage ventriculo-aortique.

Because the functional interaction between the LV and arterial systems, termed ventricular-arterial coupling, is recognized as a key determinant of LV performance, the objective of the present study was to assess the impact of uncomplicated HT without LVH on LV performance using simultaneously echocardiography and carotid tonometry. LV maximal power (PmaxVG), cardiac power output (CPO), LV efficiency (CPO/PmaxVG), input aortic and output LV elastance (Ea and Ees) were assessed in 20 normotensive control subjects (NT) and 10 patients with untreated HT. PmaxVG was calculated according to the integral of the product of LV wall stress with strain rate (as an index of gradient velocity). Cyclic variation of wall thickness and SR were measured by speckel-tracking. Ea and Ees were derived and modelized from the pressure-volume curve. No difference in age, BMI and sex ratio was observed between NT and HT. Systolic BP (160±18 vs. 119±10mmHg), LV mass (99±15 vs. 76±12g/m(2)), PWV (9.7±2 vs. 6.9±1m/s) were significantly higher (P<0.01) in HT when compared to NT. In HT increased of CPO and Ea was compensated by an increase of LV (15±4 vs. 12±3%, P<0.02) and Ees (5.5±2 vs. 4.5±1.5mmHg/mL), which are significantly elevated in HT (P<0.05). No difference was observed in Ea/Ees between NT and HT. In conclusion at the early phase of HT, in patients without LVH, LV performance and ventricular-arterial coupling were adapted to post-load elevation. This adaptation may be the result of an increased of LV contractility.

Office and ambulatory pulse pressure--association with clinical characteristics and cardiovascular risk factors in normoalbuminuric patients with type 2 diabetes (ROADMAP study).

To investigate the association of office and ambulatory 24-h pulse pressure (PP) with clinical characteristics and cardiovascular risk factors in normoalbuminuric type 2 diabetic patients enrolled to the Randomised Olmesartan and Diabetes Microalbuminuria Prevention study, 4449 patients (2054 male and 2395 female; mean age 57.7±8.7 years) with type 2 diabetes, normoalbuminuria and at least one additional cardiovascular risk factor were included into the analysis. After adjustment by age, there were significant correlations between office PP and presence of hypertension (r=0.24; P<0.001), presence of cardiac and vascular disorders (r=0.17; P<0.001), metabolic syndrome (r=0.10; P<0.001), duration of diabetes (r=0.09; P<0.001), fasting blood glucose (r=0.08; P<0.001), albumin/creatinine ratio (r=0.07; P<0.001), insulin treatment, glycosylated haemoglobin (HbA1c), male gender and current smoking. In the subgroup of 1234 patients with ambulatory blood pressure measurement performed, ambulatory PP adjusted for office PP correlated with fasting blood glucose (r=0.16; P<0.001), metabolic syndrome (r=0.14; P<0.001), albumin/creatinine ratio (r=0.11; P<0.001) and indices of glycemic control (HbA1c: r=0.11; P<0.001). In this group of normoalbuminuric type 2 diabetic patients, office and ambulatory PP were associated with duration of diabetes, indices of glycemic control and cardiovascular risk factors. There was relationship between office and ambulatory PP and albuminuria even within normal albuminuria range.

Efficacy of a potential trivalent vaccine based on Hc fragments of botulinum toxins A, B, and E produced in a cell-free expression system.

Botulinum toxins produced by the anaerobic bacterium Clostridium botulinum are the most potent biological toxins in nature. Traditionally, people at risk are immunized with a formaldehyde-inactivated toxin complex. Second generation vaccines are based on the recombinant carboxy-terminal heavy-chain (Hc) fragment of the neurotoxin. However, the materialization of this approach is challenging, mainly due to the high AT content of clostridial genes. Herein, we present an alternative strategy in which the native genes encoding Hc proteins of botulinum toxins A, B, and E were used to express the recombinant Hc fragments in a cell-free expression system. We used the unique property of this open system to introduce different combinations of chaperone systems, protein disulfide isomerase (PDI), and reducing/oxidizing environments directly to the expression reaction. Optimized expression conditions led to increased production of soluble Hc protein, which was successfully scaled up using a continuous exchange (CE) cell-free system. Hc proteins were produced at a concentration of more than 1 mg/ml and purified by one-step Ni(+) affinity chromatography. Mice immunized with three injections containing 5 microg of any of the in vitro-expressed, alum-absorbed, Hc vaccines generated a serum enzyme-linked immunosorbent assay (ELISA) titer of 10(5) against the native toxin complex, which enabled protection against a high-dose toxin challenge (10(3) to 10(6) mouse 50% lethal dose [MsLD(50)]). Finally, immunization with a trivalent HcA, HcB, and HcE vaccine protected mice against the corresponding trivalent 10(5) MsLD(50) toxin challenge. Our results together with the latest developments in scalability of the in vitro protein expression systems offer alternative routes for the preparation of botulinum vaccine.

Determinants of urinary albumin excretion within the normal range in patients with type 2 diabetes: the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) study.

AIMS/HYPOTHESIS: In contrast to microalbuminuric type 2 diabetic patients, the factors correlated with urinary albumin excretion are less well known in normoalbuminuric patients. This may be important because even within the normoalbuminuric range, higher rates of albuminuria are known to be associated with higher renal and cardiovascular risk. METHODS: At the time of screening for the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) Study, the urinary albumin/creatinine ratio (UACR) was 0.44 mg/mmol in 4,449 type 2 diabetic patients. The independent correlates of UACR were analysed. RESULTS: Independent correlates of UACR during baseline were (in descending order): night-time systolic BP (r(s) = 0.19); HbA(1c) (r(s) = 0.18); mean 24 h systolic BP (r(s) = 0.16); fasting blood glucose (r(s) = 0.16); night-time diastolic BP (r(s) = 0.12); office systolic BP, sitting (r(s) = 0.11), standing (r(s) = 0.10); estimated GFR (r(s) = 0.10); heart rate, sitting (r(s) = 0.10); haemoglobin (r(s) = -0.10); triacylglycerol (r(s) = 0.09); and uric acid (r(s) = -0.08; all p

[Renin-angiotensin system inhibition and cardiac and renal alteration induced by a high sodium diet in rat]. / Inhibition du système rénine-angiotensine et altérations cardiaque et rénale induites par une consommation excessive de sodium chez le rat.

BACKGROUND: The present study was designed to assess the influence of losartan on cardiac hypertrophy and albuminuria associated with early high sodium feeding in rats and to compare it to an angiotensin-converting enzyme inhibitor, enalapril, effect. METHODS: Male Sprague-Dawley rats received a regular diet (0.8% NaCl, NS, n=7), or high sodium diet (8% NaCl, HS, n=21) from weaning for 8 weeks. After 4 weeks of diet, two HS groups were treated or not for 4 weeks with losartan or enalapril (30 and 10 mg/kg(-1) x day(-1) respectively, n=7 in each). Food and water consumption, body weight, urinary volume and urinary excretion of sodium, potassium and albumin were measured at the end of treatment as well as arterial pressure (anesthetized rats), heart and kidney weight. RESULTS: Eight weeks after weaning, heart weight index and albuminuria were significantly higher in HS control group when compared to the control NS group without change of arterial pressure. Treatment with losartan or enalapril had no effect either on arterial pressure or cardio-renal alterations.

Angiotensin-receptor blockers and diuretics--advantages of combination.

Surveys have shown that in as many as half of patients treated for hypertension, blood pressure (BP) is not controlled to target levels; many more persons have undertreated hypertension. Uncontrolled hypertension is a serious risk factor for cardiovascular events such as stroke, heart failure, myocardial infarction and target-organ diseases. Studies have shown that strict BP control significantly reduces the occurrence of these cardiovascular outcomes, in the majority of patients, effective BP control requires two or more antihypertensive agents. The combination of an angiotensin-receptor blocker (ARB) and a thiazide diuretic is appealing, since these agents have complimentary effects on BP reduction, left ventricular hypertrophy and progression of renal diseases. In addition, this combination provide excellent tolerability. The combination of an ARB and a thiazide diuretic may be of particular value in patient populations who tend to have poor BP control on monotherapy, or have additional cardiovascular or renal risk factors.

Age-related increase of pulse pressure and plasminogen activator inhibitor-1 I/D gene polymorphism in essential hypertension.

BACKGROUND: Pulse pressure (PP), a marker of cyclic strain on the arterial wall, is a significant predictor of cardiovascular (CV) risk, particularly regarding the incidence of coronary arterial stenosis. Genes related to haemostatic and/or fibrinolytic factors are consistently influenced in vitro by mechanical strain. OBJECTIVE: The goal of the present study was to determine, in the three genotypes of the plasminogen activator inhibitor (PAI)-1 gene polymorphism, the gender-adjusted difference in the relationships between age and PP in subjects with never treated essential hypertension. RESULTS: In the studied population, the genotype deletion (D)/D at position -675 of the PAI-1 insertion (I)/D gene polymorphism was associated with a significant increase in the adjusted slope of the curve relating age to PP by comparison with the two other genotypes. No comparable difference in age-related changes in systolic, diastolic or mean blood pressure was found. CONCLUSION: In subjects with essential hypertension, the PAI-1 I/D gene polymorphism modulates the age-mediated increase of PP, suggesting new insights on the complex interactions between genes, mechanical factors and CV risk.

[I/D gene polymorphism of the angiotensin-converting enzyme and left ventricular hypertrophy. Response to converting enzyme inhibitors]. / Polymorphisme I/D du gène de l'enzyme de conversion de l'angiotensine et hypertrophie ventriculaire gauche. Réponse aux inhibiteurs de l'enzyme de conversion.

BACKGROUND: The present study was designed to assess whether the angiotensin-converting enzyme (ACE) gene I/D polymorphism influence the ACE inhibitors effect on the regression of left ventricular hypertrophy. METHODS: Sixty hypertensive subjects never treated by antihypertensive drugs, aged 46 +/- 11 years, were included in the study. Follow-up with ACE inhibitor treatment was 60 +/- 26 months. Genotypes for ACE I/D polymorphism (DD, ID or II) were determined by PCR. The left ventricular mass index (LVMI) was assessed by two-dimensional directed M-mode echocardiography. RESULTS: ACE genotype distribution was in agreement with the Hardy-Weinberg equilibrium: 21 patients had the DD genotype, 29 were ID, and 10 were II. At baseline, age, systolic arterial pressure and LVMI didn't differ on the basis of genotype. Body mass index was significantly higher in II than in ID and DD groups. Regression of LVMI with ACE inhibitor treatment was similar in the 3 genotypes (-8.9%, -0.6%, -12.1% in DD, ID and II groups respectively). In addition, decrease of systolic arterial pressure was identical in 3 groups. CONCLUSION: ACE gene I/D polymorphism seems not to influence regression of left ventricular hypertrophy by ACE inhibitors in essential hypertension.

[Influence of angiotensin I on angiogenesis in vitro in the rat]. / Influence de l'angiotensine II sur les capacités angiogéniques d'explants vasculaires de rat.

The regulation of angiogenesis involves complex interactions. The aim of our study was to assess the influence of angiotensin II (ANG II) on different vascular beds in rat. Aortic, renal and mesenteric rings from 10 male Sprague-Dawley rats were cultured using a three-dimensional culture system consisting of rat type I collagen lattice. We assessed the influence of different ANG II concentrations (10(-7) et 10(-9) mol/L) on these rings as well as the effect of AT1 blockade by losartan (10(-7 mol/L). ANG II inhibited angiogenesis at 10(-7) mol/L on renal artery. However, these was a angiogenic effect at 10(-9) mol/L on the mesenteric artery. Every time losartan prevented the effect of ANG II in any kind of vessel rings. No significant effect on ANG II was found on aortic rings but coadministration of losartan induced a dramatic decrease in the number of capillary sprouts. In conclusion, ANG II seems to be deeply involved in angiogenesis. However, its effect depends on the concentration of ANG II and the type of vessel. ANG II appears to be angiogenic on mesenteric arteries via an AT1 receptor effect and mostly anti-angiogenic on the renal arteries with possible involvement of AT2 receptors.

A population-based European cohort study of persistence in newly diagnosed hypertensive patients.

This study assessed the percentage of patients after 1 year who persisted on initially prescribed antihypertensive therapy. Medical records of 2416 patients with newly diagnosed hypertension who were prescribed initial antihypertensive monotherapy by general practitioners in Germany, France, and the United Kingdom were evaluated. Comparisons were made among the angiotensin II receptor antagonist (AIIRA) irbesartan, all other antihypertensive classes (including AIIRAs other than irbesartan), and the AIIRA losartan. Patients initiated on the AIIRA irbesartan scored highest with a persistence rate of 60.8%, followed by patients who received all other AIIRA agents with a persistence rate of 51.3%. Angiotensin-converting enzyme inhibitors, calcium channel blockers, beta-blockers, and losartan were associated with comparable persistence rates, between 42.0% and 49.7%. Patients who received diuretics scored lowest with a persistence rate of 34.4%. Persistence has emerged as an essential factor for blood pressure control. Prescribing an antihypertensive agent that provides a favourable efficacy and tolerability profile may provide greater persistence with therapy and hence a higher level of blood pressure control.

The relevance of tissue angiotensin-converting enzyme: manifestations in mechanistic and endpoint data.

Angiotensin-converting enzyme (ACE) is primarily localized (>90%) in various tissues and organs, most notably on the endothelium but also within parenchyma and inflammatory cells. Tissue ACE is now recognized as a key factor in cardiovascular and renal diseases. Endothelial dysfunction, in response to a number of risk factors or injury such as hypertension, diabetes mellitus, hypercholesteremia, and cigarette smoking, disrupts the balance of vasodilation and vasoconstriction, vascular smooth muscle cell growth, the inflammatory and oxidative state of the vessel wall, and is associated with activation of tissue ACE. Pathologic activation of local ACE can have deleterious effects on the heart, vasculature, and the kidneys. The imbalance resulting from increased local formation of angiotensin II and increased bradykinin degradation favors cardiovascular disease. Indeed, ACE inhibitors effectively reduce high blood pressure and exert cardio- and renoprotective actions. Recent evidence suggests that a principal target of ACE inhibitor action is at the tissue sites. Pharmacokinetic properties of various ACE inhibitors indicate that there are differences in their binding characteristics for tissue ACE. Clinical studies comparing the effects of antihypertensives (especially ACE inhibitors) on endothelial function suggest differences. More comparative experimental and clinical studies should address the significance of these drug differences and their impact on clinical events.

Glucose tolerance and age-associated decline in renal function of hypertensive patients.

BACKGROUND: Renal function is thought to decrease with age in the general population, but the determinants of this age-associated evolution are poorly understood. Hypertension and diabetes mellitus, two leading causes of chronic renal failure in the elderly, may accelerate this decline. PATIENTS AND METHODS: Urinary clearances of [99mTc]diethylene triaminopentaacetic acid (DTPA) (glomerular filtration rate) and [131I]hippuran (effective renal plasma flow) were assessed in 227 never-treated essential hypertensives aged 20-69 years. Based on the oral glucose tolerance test, the study population consisted of 4% patients with previously unknown diabetes mellitus, 24% with impaired glucose tolerance and 72% with normal glucose tolerance. RESULTS: When the population of 218 non-diabetic subjects was considered, glomerular filtration rate was inversely correlated with age and arterial blood pressure, and positively correlated with effective renal plasma flow, filtration fraction and fasting plasma glucose. In multivariate analysis, age and blood pressure were independent determinants of renal plasma flow, whereas renal plasma flow, age and fasting plasma glucose were independent determinants of glomerular filtration rate. The slope of the regression line relating glomerular filtration rate to age was steeper in patients with impaired glucose tolerance than in those with normal glucose tolerance (-1.52 +/- 0.28 versus -0.65 +/- 0.12, P < 0.01). CONCLUSIONS: These results suggest that impaired glucose tolerance, which is seldom searched for in patients with essential hypertension, may be an important determinant of the age-associated decline in renal function.

Influence of irbesartan and enalapril on changes of renal function associated with the established phase of l-NAME hypertension.

OBJECTIVE: Reversibility of the systemic and renal alterations induced by N(omega)-nitro-L-arginine-methyl ester(L-NAME) was assessed by treatment with irbesartan and enalapril (30 and 10 mg/kg per 24 h, respectively) alone or in combination. DESIGN: L-NAME (20 mg/kg per 24 h) was given to rats for 6 weeks and treatments were administered during the last 2 weeks. Glomerular filtration rate and renal plasma flow [GFR and RPF per g of kidney weight (KW)] were determined using the clearance technique. RESULTS: Arterial pressure was similarly reduced by treatments. GFR was lower in L-NAME-treated rats than in controls (552 +/- 52 versus 1106 +/- 78 microl/min per g KW), whereas RPF was reduced to a larger extent, thus resulting in an increase in filtration fraction. GFR was normalized by irbesartan but not enalapril or the combination (1042 +/- 50, 790 +/- 79 and 725 +/- 38 microl/min per g KW, respectively). RPF returned to normal and filtration fraction fell markedly with the combination. All treatments reduced the lesions of preglomerular vessels and reversed L-NAME-induced albuminuria and cardiovascular hypertrophy. At a dose of 3 mg/kg per 24 h, irbesartan only reduced the lesions of the afferent arteriole. CONCLUSIONS: Through its effects on AT1 receptors, angiotensin II may play an important role in the maintenance of L-NAME hypertension and associated alterations. The lower GFR and filtration fraction observed with enalapril in the presence of irbesartan suggests the intervention of non-angiotensin II-mediated mechanism, and at the postglomerular level, in the effect of angiotensin-converting enzyme (ACE) inhibitors.

Autoimmunity to the p53 protein is a feature of systemic lupus erythematosus (SLE) related to anti-DNA antibodies.

The induction of anti-DNA autoantibodies in systemic lupus erythematosus (SLE) patients is problematic because mammalian DNA is poorly immunogenic at best. Here we demonstrate a chain of connected antibodies in SLE patient sera that could account for the induction of anti-DNA antibody, and possibly for some of the pathogenic features of SLE. We now report that SLE patients, in addition to anti-DNA, produce antibodies to the carboxy-terminal domain of the tumour suppressor molecule p53; this p53 domain recognizes damaged DNA. Hence, these anti-p53 antibodies could mimic damaged DNA immunologically. Indeed, SLE sera do contain anti-idiotypic antibodies to a prototypic anti-p53 antibody. Moreover, SLE anti-DNA antibodies also recognize this type of anti-p53 antibody. Indeed, binding of affinity-purified anti-DNA both to DNA and to the anti-p53 antibody could be blocked by a p53 peptide derived from the DNA-binding domain. This mimicry of the p53 DNA-binding domain by the SLE anti-DNA antibodies is functional: activation of the p53 molecule could be inhibited by such anti-DNA antibodies. Thus, anti-DNA antibodies may arise in SLE patients by a chain of idiotypic autoimmunity centered around p53 autoimmunity. The SLE anti-DNA and anti-p53 antibodies can functionally block p53 activation, and so could affect apoptosis.

Endothelin gene variants and aortic and cardiac structure in never-treated hypertensives.

BACKGROUND: The polymorphism of several candidate genes has been studied in relation to essential hypertension and cardiovascular complications. Target organ damage in essential hypertension is a complex disorder influenced by multiple genetic and environmental factors. The possible contribution of endothelin gene variants to target organ damage in hypertension in humans has not been studied in depth. PROCEDURE: We assessed the influence of genetic variants of components of the endothelin system ETAR -231A/G, 1363C/T, ETBR 30G/A and endothelin-1 (ET-1) 138insertion/deletion (I/D) on aortic stiffness, left ventricular geometric, and radial artery parameters in 528 never-treated hypertensive subjects of European origin. The study population included 314 men and 214 women with a mean age of 48+/-0.5 years (+/-SEM). In samples of patients, aortic stiffness was assessed with carotid-femoral pulse wave velocity (PWV). Radial artery thickness was measured with an echotracking angiometer and left ventricular geometric parameter with standard echographic procedures. RESULTS: The main results showed that the ETAR-231A/G (P = .022) and the ETBR 30G/A (P = .026) receptor gene variants influenced PWV level in women. The -231G and 30G alleles were associated with a codominant increase in PWV, explaining 18.6% of its variability (P = .005). In men, the ETBR 30G/A receptor gene variant was also related to the level of radial artery parameters (P = .02). No association between the 138I/D polymorphism of the ET-1 gene and left ventricular and radial artery parameters was observed in either men or women. CONCLUSIONS: These results indicate that the influence of endothelin system genes can be detected first on arterial parameters.

Inhibition of the acute effects of angiotensin II by the receptor antagonist irbesartan in normotensive men.

Irbesartan (SR 47436, BMS 186295) is an imidazole derivative that specifically binds to the angiotensin type 1 receptor. The purpose of this study was to assess the inhibitory effect of irbesartan on the pressor action of exogenous angiotensin II in healthy subjects, to evaluate the dose dependency and duration of this inhibition, and to determine the effect of irbesartan on plasma components of the renin-angiotensin system. Forty-two healthy male volunteers maintained on ad libitum sodium intake were enrolled in a randomized, double-blind, placebo-controlled, parallel-design, dose-ranging study. On 2 study days 1 week apart, volunteers were given either a placebo or the active drug at one of the chosen doses (5, 25, 50, 75, 100, 150, or 300 mg). The pressor effects of an individually titrated test dose of exogenous angiotensin II as well as plasma levels of angiotensin II, active renin, aldosterone, and treatment drug were determined before and throughout the 24 h after drug administration. The inhibitory effect of irbesartan on the pressor response to angiotensin II was observed within 1 h after dosing, peaked between 2 and 4 h, and lasted more than 24 h for doses of 25 mg and more. The effect was clearly dose related. Two and 24 h after administration of irbesartan, 300 mg, the response of arterial blood pressure (systolic and diastolic) to a given dose of angiotensin II was reduced by approximately 100% and 60%, respectively. Plasma concentrations of angiotensin II and active renin increased markedly after irbesartan administration, whereas plasma concentrations of aldosterone decreased. No evidence was found that the high levels of circulating angiotensin II observed after irbesartan administration could override the inhibitory effect of irbesartan on any of the measured parameters up to 24 h after dose. In conclusion, irbesartan appears to be a well-tolerated, orally active, potent antagonist of the renin-angiotensin system in men.

Endothelin blockade in angiotensin II hypertension: prevention and treatment studies in the rat.

1. The participation of endothelin (ET) in the development and maintenance of hypertension induced by angiotensin (Ang) II was assessed using the non-specific ET receptor antagonist bosentan (30 mg/kg per day). 2. In the prevention study, bosentan was given 24 h prior to and during the 17 day period of AngII infusion (200 ng/kg per min, s.c., osmotic pump), whereas in the treatment study, bosentan was administered from day 10 to day 17. Tail-cuff pressure (TCP) was measured before and on days 10 and 17 of AngII infusion. At the end of studies, heart weight index was calculated as the ratio of heart to bodyweight (HWI) and the wall thickness of the carotid artery (perfusion/fixation at 120 mmHg) was measured. Tail-cuff pressure increased from 129 +/- 3 to 179 +/- 7 and 189 +/- 9 mmHg on days 10 and 17 of AngII infusion, respectively. 3. Final TCP was markedly lowered in rats pretreated with bosentan, whereas TCP remained comparable with untreated hypertensive rats when bosentan was given from day 10 of AngII infusion (177 +/- 9 mmHg). 4. The increase in cardiac mass associated with AngII hypertension was similarly attenuated in the two groups receiving bosentan. 5. The HWI was 3.49 +/- 0.12 mg/g in untreated hypertensive rats and 3.18 +/- 0.08 and 3.11 +/- 0.09 mg/g in rats pretreated with bosentan and those receiving the antagonist from day 10. 6. The increase in carotid wall thickness induced by AngII was prevented, but not reversed, by bosentan. 7. These results support the hypothesis that endogenous ET participates only in the initial phase of AngII hypertension. In addition, the beneficial effect of bosentan of cardiac mass but not on arterial wall thickness is in favour of a role of ET as a local mediator of the cardiac hypertrophic effect of AngII, independently of the level of blood pressure and duration of hypertension.

Nitric oxide inhibition and renal alterations.

Acute and chronic administrations of L-arginine analogues are associated with renal functional and structural alterations that can be prevented or reversed by pharmacological blockade of other vasoactive systems. When given acutely, L-arginine derivatives have an antinatriuretic effect that is overridden by elevation of perfusion pressure and both endothelin and angiotensin II play an important role in the systemic and renal haemodynamic alterations associated with impaired nitric oxide availability. Long-term administration of L-arginine derivatives, mainly NG-nitro-L-arginine methylester (L-NAME), resulted in hypertension, intrarenal vascular, tubular and glomerular lesions and reduction in renal function. In prevention studies, blockade of the renin-angiotensin system markedly reduced hypertension and the renal morphological alterations associated with L-NAME administration. Although improvement in renal function may be achieved when arterial pressure is fully controlled, several reports indicate that the L-NAME-induced renal structural changes were independent of blood pressure and at least partly mediated by endothelin. In intervention studies, blockers of the renin-angiotensin system decreased but did not completely normalize arterial pressure, improved renal function and normalized albuminuria. Both the renin-angiotensin and the sympathetic nervous systems contribute to the sustained phase of chronic nitric oxide synthase inhibition, the adrenergic component being prominent with time. L-NAME hypertension can also be reversed by calcium antagonists, possibly via inhibition of angiotensin II-induced vasoconstriction, and the T-type antagonist had a greater effect than the L-type antagonist in reducing pre-glomerular resistance. The rat model of hypertension induced by chronic inhibition of nitric oxide generation has provided a useful tool to study both the development and the treatment of renal lesions resembling those found in human hypertension, a disease associated with early generalized impairment of endothelial function.