Hemodynamic effects of the angiotensin II receptor antagonist irbesartan in patients with cirrhosis and portal hypertension

BACKGROUND & AIMS: Angiotensin II receptor antagonists have been proposed as new drugs for portal hypertension. This randomized, placebo-controlled, double-blind study aimed to assess the effect of the angiotensin II receptor antagonist irbesartan on portal and systemic hemodynamics and renal function in patients with cirrhosis. METHODS: Thirty-six patients with cirrhosis and portal hypertension received 150 mg/d irbesartan or placebo for 1 week. Systemic hemodynamics, kidney and liver function parameters were recorded regularly; hepatic venous pressure gradient and plasma renin were assessed on days 0 and 7. RESULTS: Irbesartan reduced the hepatic venous pressure gradient by 12.2% +/- 6.6% (P < 0.05) and mean arterial pressure by 5.3% +/- 4.0% in 13 of 18 verum patients. In 4 (22%) verum patients, arterial hypotension, accompanied by significant renal impairment, required withdrawal of irbesartan. In these patients, baseline plasma renin (P < 0.002) and cystatin C (P < 0.001) levels were higher, and creatinine clearance (P < 0.02), serum sodium (P < 0.01), and albumin (P < 0.05) were lower than in patients who tolerated irbesartan. Four of five patients with baseline renin >900 microU/mL developed treatment-limiting hypotension. CONCLUSIONS: The angiotensin II receptor antagonist irbesartan is not advisable in patients with advanced cirrhosis and high plasma renin because it may induce arterial hypotension and only moderately reduces portal pressure.     

Selective endothelin-A receptor antagonism reduces proteinuria, blood pressure, and arterial stiffness in chronic proteinuric kidney disease

Proteinuria is associated with adverse cardiovascular and renal outcomes that are not prevented by current treatments. Endothelin 1 promotes the development and progression of chronic kidney disease and associated cardiovascular disease. We, therefore, studied the effects of selective endothelin-A receptor antagonism in proteinuric chronic kidney disease patients, assessing proteinuria, blood pressure (BP), and arterial stiffness, key independent, surrogate markers of chronic kidney disease progression and cardiovascular disease risk. In a randomized, double-blind, 3-way crossover study, 27 subjects on recommended renoprotective treatment received 6 weeks of placebo, 100 mg once daily of sitaxsentan, and 30 mg once daily of nifedipine long acting. Twenty-four-hour proteinuria, protein:creatinine ratio, 24-hour ambulatory BP, and pulse wave velocity (as a measure of arterial stiffness) were measured at baseline and week 6 of each treatment. In 13 subjects, renal blood flow and glomerular filtration rate were assessed at baseline and week 6 of each period. Compared with placebo, sitaxsentan reduced 24-hour proteinuria (-0.56±0.20 g/d; P=0.0069), protein:creatinine ratio (-38±15 mg/mmol; P=0.0102), BP (-3.4±1.2 mm Hg; P=0.0069), and pulse wave velocity (-0.64±0.24 m/s; P=0.0052). Nifedipine matched the BP and pulse wave velocity reductions seen with sitaxsentan but did not reduce proteinuria. Sitaxsentan alone reduced both glomerular filtration rate and filtration fraction. It caused no clinically significant adverse effects. Endothelin-A receptor antagonism may provide additional cardiovascular and renal protection by reducing proteinuria, BP, and arterial stiffness in optimally treated chronic kidney disease subjects. The antiproteinuric effects of sitaxsentan likely relate to changes in BP and renal hemodynamics.     

大剂量厄贝沙坦治疗慢性肾脏病患者临床蛋白尿的疗效及安全性

目的 评估大剂量厄贝沙坦治疗慢性肾脏病(CKD)患者轻、中度蛋白尿的疗效与安全性.方法 采用单中心前瞻观察性研究,将96例受试者先行厄贝沙坦150 mg/d治疗4周,疗效达好转标准者作为厄贝沙坦单倍剂量组( 150 mg/d)(26例);若单倍剂量治疗无效,逐渐加大厄贝沙坦治疗剂量作为大剂量组( 300～ 600 mg...     

Effect of telmisartan on blood pressure control and kidney function in hypertensive, proteinuric patients with chronic kidney disease

OBJECTIVES: To assess the antihypertensive and antiproteinuric efficacy and safety of the angiotensin II type 1 receptor blocker telmisartan in patients with hypertension and chronic kidney disease. METHODS: A multicenter, prospective trial was performed in adults with hypertension [systolic blood pressure (SBP)/diastolic blood pressure (DBP) >130/85 mmHg), chronic renal insufficiency (serum creatinine <4.0 mg/dl), and proteinuria (>1 g/24 h). In addition to existing antihypertensive therapy, the nature and doses of which remained unchanged throughout the study, patients received once-daily telmisartan 40 mg for the first 3 months followed by forced titration to telmisartan 80 mg for the subsequent 3 months to achieve a target SBP/DBP of <130/85 mmHg. The rationale for using telmisartan was its long half-life efficacy, greater antihypertensive effect compared with valsartan or losartan, and newly discovered potential antidiabetic effect. RESULTS: The study was conducted in 92 patients (45 men, 47 women), of whom 60 had diabetes mellitus (54 patients with type 2 disease). Five patients discontinued prematurely: two because of hyperkalemia, two because of protocol violation, and one because of lack of efficacy. After 6 months' telmisartan treatment, office trough seated SBP was reduced by 19.6 mmHg (P<0.001) from 154.9+/-14.6 mmHg and DBP by 11.8 mmHg (P<0.001) from 91.7+/-8.1 mmHg. Seated trough SBP/DBP of <130/85 mmHg was achieved at 6 months in 34.8% of patients. Ambulatory blood pressure monitoring also demonstrated significant reductions in mean daytime SBP of 10.9 mmHg (P=0.01), night-time SBP of 12.1 mmHg (P=0.05), daytime DBP of 3.1 mmHg (P=0.05), and night-time DBP of 6.5 mmHg (P=0.05). Proteinuria decreased significantly from 3.6+/-3.4 to 2.8+/-2.8 g/24 h (P=0.01). A decrease in proteinuria depended significantly on a decrease in SBP at the end of the study (P=0.044). Each decrease in SBP of about 10 mmHg led to a decrease in proteinuria of about 0.79 g/24 h (95% CI 0.02-1.56 g/24 h). Serum creatinine increased from 1.96+/-0.79 to 2.08+/-0.89 mg/dl (P=0.01), whereas creatinine clearance did not change significantly. CONCLUSIONS: Telmisartan effectively and safely reduced blood pressure and brought about regression of proteinuria in diabetic and nondiabetic, hypertensive, proteinuric patients with chronic kidney disease, even in those with mild-to-moderate chronic renal failure.     

Role of angiotensin II, endothelin-1 and L-type calcium channel in the development of glomerular, tubulointerstitial and perivascular fibrosis

OBJECTIVE: Fibrosis is a hallmark of renal damage in several diseases, including arterial hypertension. We, therefore, investigated the role of angiotensin II, endothelin-1 and of L-type calcium channels in the development of the glomerular, vascular, and tubulointerstitial fibrosis in a model of severe angiotensin II-dependent hypertension. METHODS: Five-week-old Ren-2 transgenic rats (TGRen2) received for 4 weeks a placebo, bosentan (100 mg/kg body weight), irbesartan (50 mg/kg body weight), the ETA-selective endothelin receptor antagonist BMS-182874 (BMS; 52 mg/kg body weight), the combination of irbesartan (50 mg/kg body weight) plus BMS (52 mg/kg body weight), and nifedipine (30 mg/kg body weight). RESULTS: Glomerular volume, tubulointerstitial fibrosis, glomerular, and perivascular fibrosis were accurately quantified by histomorphometry in four-to-six sections per kidney. Glomerular fibrosis was lowered by BMS (P < 0.001), whereas tubulointerstitial fibrosis was blunted by bosentan (P < 0.001) and irbesartan (P < 0.005). Perivascular fibrosis was reduced by nifedipine and BMS. As only irbesartan and irbesartan plus BMS decreased blood pressure (P < 0.001 vs. placebo), these effects on fibrosis were independent of blood pressure. CONCLUSION: Angiotensin II and L-type calcium channels modulate fibrosis selectively in the tubulointerstitial and in the perivascular compartments, respectively. The prevention of fibrosis with ET-1 receptor antagonism in all three compartments supports a major role of ET-1 in the development of renal fibrosis.     

A comparison of the efficacy and safety of irbesartan/HCTZ combination therapy with irbesartan and HCTZ monotherapy in the treatment of moderate hypertension

This prospective, double-blind, parallel-group study randomized patients with moderate hypertension (seated systolic blood pressure (SeSBP) 160-179 mm Hg when seated diastolic blood pressure (SeDBP) <110 mm Hg; or SeDBP 100-109 mm Hg when SeSBP <180 mm Hg) 3:1:1 to treatment with irbesartan 300 mg/hydrochlorothiazide (HCTZ) 25 mg combination therapy (n=328), irbesartan 300 mg monotherapy (n=106) or HCTZ monotherapy 25 mg (n=104). Treatment was initiated at half dose, with forced titration to full dose after two weeks followed by ten further weeks' treatment. The primary efficacy variable was the mean reduction in SeSBP from baseline to week 8. Baseline characteristics were similar between groups, with mean baseline blood pressure approximately 162/98 mm Hg; the mean age was 55 years. At week 8 there was a reduction in SeSBP of 27.1 mm Hg with irbesartan/HCTZ, compared with 22.1 mm Hg with irbesartan monotherapy (P=0.0016) and 15.7 mm Hg with HCTZ (P<0.0001). Both the rate of decline and the total degree of decline achieved were greatest with irbesartan/HCTZ and least with HCTZ. A significantly greater percentage of patients reached a treatment goal of SeSBP <140 mm Hg and SeDBP <90 mm Hg by week 8 with irbesartan/HCTZ (53.4%), compared with irbesartan (40.6%; P=0.0254) and HCTZ (20.2%; P<0.0001) alone. Treatment was well tolerated in all three-treatment groups with a slight increase in adverse events in the combination therapy group. In conclusion, irbesartan/HCTZ (300/25 mg) is well tolerated and achieves rapid and sustained reductions in both systolic blood pressure and diastolic blood pressure in patients with moderate hypertension.     

厄贝沙坦/氢氯噻嗪复方片剂治疗中国高血压病患者的达标率分析

目的分析高血压患者接受厄贝沙坦／氢氯噻嗪复方制剂（商品名：安博诺）治疗的达标率。方法本研究为多中心、开放、单一治疗组的研究。共入选968例轻、中度高血压病患者,均采用安博诺治疗8周。经药物清洗1～2周后,给予初始剂量安博诺1片／d治疗,治疗2周末,如未达标（目标血压：舒张压〈85mm Hg,1mm Hg = 0．133 kPa）则增加厄贝沙坦150mg继续服用2周;在第4周末仍未达标则再增加氢氯噻嗪12．5mg（即安博诺2片／d）直至8周试验结束。结果对入选的968例轻、中度高血压病患者进行意向治疗人群分析,完成8周随访的920例患者进行符合方案人群分析。（1）治疗1周时,收缩压／舒张压与治疗前比较,分别降低11．8／8．56mm Hg,P 〈 0．01;治疗8周时,收缩压／舒张压分别降低21．97／16．08mm Hg,P 〈 0．01。（2）治疗2周血压达标的患者526例,占57．17％;4周时血压达标患者703例,占76．41％;8周时达标患者769例,占83．59％。（3）在治疗的8周中服用安博诺1片／d为637例,占总病例数的69．24％;服用安博诺1片＋厄贝沙坦150mg／d为211例,占总病例数的22．93％;安博诺2片／d为72例,占总病例数的7．82％。（4）入组的968例高血压病患者进行意向治疗人群分析,其中有903例患者没有任何不良反应,占总研究病例数的93．29％。结论安博诺治疗中国轻、中度高血压病达标率高,不良反应较少。     

Proteinuria in renal artery occlusion is related to active renin concentration and contralateral kidney size.

OBJECTIVES: Angiotensin II, in addition to having vasopressor effects, induces proteinuria in experimental models. Proteinuria has been reported, sometimes in the nephrotic range, in patients with chronic complete renal artery occlusion. We aimed to identify the factors associated with proteinuria in such cases. DESIGN AND MAIN OUTCOME MEASURE: Complete renal artery occlusion was detected by intra-arterial angiography in 96 patients referred for hypertension. We analysed patient characteristics at presentation to identify the factors associated with proteinuria. SETTING: A referral hypertension unit. RESULTS: Median protein excretion was 0.25 g/day (range 0-11). Nine patients had nephrotic syndrome (proteinuria >/= 3.5 g/day per 1.73 m2). Patients in the upper tertile for proteinuria differed from those with lower proteinuria in terms of total cholesterol levels (P < 0.01), the proportion of diabetics (P < 0.01) and supine active renin concentration (P = 0.02). They tended to have higher systolic blood pressure levels (P = 0.07), a lower frequency of contralateral renal artery stenosis (P = 0.09) and a longer contralateral kidney (P = 0.09). In multivariate logistic regression, the factors independently linked to proteinuria in the upper tertile were active renin concentration (P = 0.05) and contralateral kidney length (P = 0.02). Proteinuria significantly decreased in nephrotic patients (P < 0.01) treated with revascularization or nephrectomy and/or angiotensin converting enzyme inhibition. CONCLUSIONS: Proteinuria in renal artery occlusion is positively related to active renin concentration, which reflects plasma angiotensin II concentration. Therapy aimed at lowering angiotensin II levels decreased proteinuria in nephrotic patients. The positive relationship between proteinuria and contralateral kidney length may reflect compensatory hypertrophy in response to nephron function loss.     

Decline of renal function is associated with proteinuria and systolic blood pressure in the morning in diabetic nephropathy

The aim of this study was to investigate a significance of increased proteinuria in the morning and the effects of antihypertensive treatment on proteinuria and arterial blood pressure in the progression of chronic renal insufficiency in type 2 diabetic patients with hypertension and nephropathy. In three 24-hr urine samples and blood pressure monitoring, separated into a night-and daytime and spot urine in the morning, variation in protein-creatinine ratio (g/g) and blood pressure were assessed in 24 (58 +/- 3 years old; M/F: 17/7) diabetic patients with hypertension and nephropathy. Furthermore, the effects of antihypertensive therapy of combinations of angiotensin converting enzyme (ACE) inhibitor, calcium antagonists, diuretics, and alpha1 blocker were evaluated in 3 years. Home blood pressure measurement was carried out every month and 24-hr urine was collected every 2 months. The baseline urine excretion of protein-creatinine ratio and blood pressure were (1.22 +/- 0.13 g/g creatinine: 154/96 +/- 6/5 mmHg) in daytime and (1.39 +/- 0.13: 168/88 +/- 15/7) in the morning. At the end of the study, significant associations among a decline of 24-hr creatinine clearance and both of the urine excretion of protein-creatinine ratio (r = 0.47, p < .01) and the levels of systolic blood pressure (r = 0.46, p < .01) and between the levels of systolic blood pressure and the urine excretion of protein-creatinine ratio in the morning (r = 0.57, p < .001) were demonstrated. However, there were no significant associations among other variables. Analysis of patients who had systolic blood pressure in the morning less than 140 mmHg revealed that 65% of these patients received doxazosin-averaged doses of 4.8 +/- 1.5 mg daily. The levels of both blood pressure and proteinuria-creatinine ratio in the morning mainly associate with progression of renal function in diabetic patients with hypertension and nephropathy.     

The long-term antihypertensive activity and tolerability of irbesartan with hydrochlorothiazide.

The long-term safety, tolerability, and antihypertensive effects of irbesartan/hydrochlorothiazide (HCTZ) were assessed in hypertensive patients (seated diastolic blood pressure [SeDBP] 95-110 mm Hg). Patients (n = 1098) completing two randomised, double-blind trials of irbesartan alone, HCTZ alone, irbesartan/HCTZ combinations, or placebo, took 1 year of open-label therapy starting with irbesartan 75 mg/HCTZ 12.5 mg once daily. If target blood pressure (BP) (<140/<90 mm Hg) was not achieved, the dose was titrated sequentially at 2- to 4-week intervals to irbesartan 150 mg/HCTZ 12. 5 mg, then to irbesartan 300 mg/HCTZ 25 mg. If necessary, adjunctive therapies were added. Mean changes in trough seated systolic BP/SeDBP at months 2, 6, and 12 were -19.1/-14.2 mm Hg (n = 941), -20.7/ -15.7 mm Hg (n = 948), and -20.6/-15.6 mm Hg (n = 898), respectively. From months 2 to 12, normalisation rates (trough SeDBP <90 mm Hg) ranged from 75-85% and total responder rates (normalised or >/=10 mm Hg trough SeDBP reduction) ranged from 81-91%, while target BP was achieved in 65-75% of patients. At all time-points, most patients (>/=87%) were receiving irbesartan/HCTZ alone. Eighty-two patients (7.5%) discontinued the study due to adverse events, with half of these events considered unrelated to study medication. There were no reports of serious adverse events related to study medication. Long-term therapy with irbesartan/HCTZ is safe, well tolerated, and maintains normalised BP in >80% of patients.     

Direct Renin inhibition with aliskiren in obese patients with arterial hypertension

Current guidelines from the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommend first-line treatment with a thiazide diuretic but do not provide specific guidance for obese patients. The renin system is activated in obesity-associated arterial hypertension. Therefore, we tested the hypothesis that the oral direct renin inhibitor aliskiren could provide additive blood pressure lowering in obese patients with hypertension (body mass index >or=30 kg/m(2); mean sitting diastolic blood pressure: 95 to 109 mm Hg) who had not responded to 4 weeks of treatment with hydrochlorothiazide (HCTZ) 25 mg. After a 2- to 4-week washout, 560 patients received single-blind HCTZ (25 mg) for 4 weeks; 489 nonresponders were randomly assigned to double-blind aliskiren (150 mg), irbesartan (150 mg), amlodipine (5 mg), or placebo for 4 weeks added to HCTZ (25 mg), followed by 8 weeks on double the initial doses of aliskiren, irbesartan, or amlodipine. After 8 weeks of double-blind treatment (4 weeks on the higher dose), aliskiren/HCTZ lowered blood pressure by 15.8/11.9 mm Hg, significantly more (P<0.0001) than placebo/HCTZ (8.6/7.9 mm Hg). Aliskiren/HCTZ provided blood pressure reductions similar to those with irbesartan/HCTZ and amlodipine/HCTZ (15.4/11.3 and 13.6/10.3 mm Hg, respectively), with similar tolerability to placebo/HCTZ. Adverse event rates were highest with amlodipine/HCTZ because of a higher incidence of peripheral edema (11.1% versus 0.8% to 1.6% in other groups). In conclusion, combination treatment with aliskiren is a highly effective and well-tolerated therapeutic option for obese patients with hypertension who fail to achieve blood pressure control with first-line thiazide diuretic treatment.     

Male gender and not the severity of hypertension is associated with end-organ damage in aged stroke-prone spontaneously hypertensive rats

BACKGROUND: It is well-known that gender affects the progression of kidney failure. Male patients exhibit faster development of age-dependent renal disease than do women. In the present study, we examined arterial blood pressure (BP), proteinuria, and end-organ damage in male and female retired breeders from our colony of stroke-prone spontaneously hypertensive rats (SHRSP). METHODS: Male (n = 7) and female (n = 11) SHRSP littermates maintained on Purina Laboratory Chow 5008 and water were studied starting at 53 weeks of age. Systolic BP was measured by tail-cuff plethysmography and 24-h urinary protein excretion was quantified while animals were housed in metabolic cages. Blood was obtained by retro-orbital bleeding. Mean arterial pressure (MAP) was then monitored by radiotelemetry. Organs were preserved for histopathologic assessment. RESULTS: Tail-cuff systolic BP did not differ between the sexes. Male SHRSP exhibited greater proteinuria (128 +/- 7 mg/d) than females (21 +/- 5 mg/d, P < .001). Blood urea nitrogen was higher in males (22 +/- 2 mg%) v females (15 +/- 1 mg%, P < .005). The MAP by radiotelemetry did not differ between the sexes (179 +/- 3 mm Hg in males v 192 +/- 6 mm Hg in females, 2 weeks after probe implantation). Stroke-related mortality was greater in males (83%) than females (10%). Renal vascular disease including thrombotic microangiopathy affecting glomeruli and microvessels and cardiac damage were more prominent in male SHRSP. CONCLUSIONS: These findings demonstrate that male gender is a major risk factor for multisystem end-organ damage associated with aging and hypertension in SHRSP, despite comparable degrees of hypertension among males and females.     

Amiloride reduces stroke and renalinjury in stroke-prone hypertensive rats

BACKGROUND: We previously reported that the mineralocorticoid receptor antagonists spironolactone and eplerenone markedly reduce proteinuria and vascular injury in saline-drinking stroke-prone spontaneously hypertensive rats (SHRSP). Presently, we examined whether amiloride, an epithelial sodium channel blocker, would also protect against pathology in these rats. METHODS: In acute studies, saline-drinking SHRSP (n = 5) were instrumented with radiotelemetry blood pressure (BP) probes and housed in metabolic cages. Mean arterial pressure and electrolyte excretion were quantified over the 24-h period after oral administration of vehicle or amiloride at 1, 3, 10, and 30 mg/kg. In a survival study, 8.5-week-old SHRSP were either untreated (control, n = 7) or given amiloride (1 mg/kg/day, n = 8) in their 1% NaCl drinking solution. Systolic BP, proteinuria, body weight, and renal and brain histopathology were assessed. RESULTS: Acute amiloride treatment did not alter urine output, urinary electrolyte excretion, and sodium-to-potassium ratio or body weight. The mean arterial pressure was unaffected except for a 16-mm Hg reduction at 30 mg/kg (P <.01). Six of eight SHRSP chronically treated with amiloride survived through 20 weeks of age, whereas all control SHRSP died by 16.4 weeks (P <.0001). Amiloride delayed proteinuria (119 +/- 24 v 15 +/- 2 mg/day, P <.002) with no significant effect on systolic BP (228 +/- 6 v 217 +/- 4 mm Hg) at 12 weeks of age. CONCLUSIONS: These findings suggest that interference with sodium channel function, perhaps at sites other than the kidney epithelium, may play a role in protecting against the evolution of cerebral and renal vascular injury in saline-drinking SHRSP.     

Safety and Tolerability of Fixed-Dose Irbesartan/Hydrochlorothiazide for Rapid Control of Severe Hypertension

This prospective, double-blind, multicenter trial compared the safety and tolerability of irbesartan/hydrochlorothiazide (HCTZ) fixed-dose combination therapy with irbesartan monotherapy in patients with severe hypertension (seated diastolic blood pressure (SeDBP) ≥110 mm Hg, mean BP 172/113 mm Hg at baseline). Patients were randomized 2:1 to 7 weeks' irbesartan/HCTZ 150/12.5 mg to 300/25 mg (n = 468) or irbesartan 150 mg to 300 mg (n = 227). The incidence of treatment-related adverse events (AEs) was similar with combination and monotherapy (11.3% and 10.1%), and most AEs were mild-to-moderate. The combined incidence of prespecified AEs was lower with irbesartan/HCTZ than with irbesartan (8.8% vs. 11.5%). There were no treatment-related serious AEs or deaths. At week 5, more patients achieved SeDBP < 90 mm Hg compared to irbesartan (47% vs. 33%; P = 0.0005). Despite more rapid and aggressive BP lowering, initial fixed-dose irbesartan/HCTZ demonstrated a comparable AE profile to irbesartan monotherapy in patients with severe hypertension.     

伊贝沙坦与依那普利联用改善高血压病早期肾损害的观察

目的: 评价伊贝沙坦合用依那普利对原发性高血压患者早期肾功能损害的有效性和安全性。方法: 将110例经血、尿中β2微球蛋白（β2-MG）检测证实具有早期肾功能损害的轻、中度高血压患者,随机分为3组, 即伊贝沙坦组(A组,50例):口服伊贝沙坦150~300 mg/d;依那普利组(B组,26例):口服依那普利5~10 mg/d及伊贝沙坦加依那普利组(C组,34例)。所有入选病例均治疗12周,治疗前后测量血压并采用ELISA法检测血、尿中β2-MG的水平;采用彩色超声多普勒仪检查肾血流量及肾血管重构的情况。结果: 与治疗前相比较,治疗12周后3组患者的收缩压、舒张压均明显下降（P<0.01）;血、尿中β2-MG的水平明显降低（P<0.01）;肾阻力指数（RI）、搏动指数（PI）及平均流速（Vm）明显改善（P<0.01）。治疗后肾血管管壁的厚度及肾动脉的内径与治疗前有显著性差异（P<0.05）。伊贝沙坦与依那普利联合治疗组与单用伊贝沙坦或依那普利治疗组比较,血、尿中β2-MG的水平及肾血管重构指标有显著改善（P<0.01或P<0.05）。 结论: 伊贝沙坦与依那普利联用对有早期肾功能损害的高血压患者,不仅有明显的降压作用,而且有明显改善肾功能的作用。     

Irbesartan plus low-dose propranolol versus low-dose propranolol alone in cirrhosis: a placebo-controlled, double-blind study

OBJECTIVES:  Angiotensin II receptor antagonists have been shown to moderately lower portal pressure in some patients with cirrhosis but may have adverse effects on kidney function. This study aimed at comparing the effects of a combined treatment using irbesartan plus propranolol with propranolol monotherapy on portal pressure and kidney function in patients with cirrhosis.
METHODS:  Thirty-two patients were included (Child A/B/C: 13/18/1, etiology: 16 alcohol, 13 viral, 3 other; bilirubin 1.4 ± 1.1 mg/dL, creatinine 0.86 ± 0.20 mg/dL, baseline hepatic venous pressure gradient 18.7 ± 5.3 mmHg). All patients received 20 mg propranolol b.i.d. Additionally, they randomly received either placebo (N = 15) or irbesartan (step-up dosage titration up to 300 mg/d, N = 17). Patients were followed at weekly intervals, re-evaluation of hepatic venous pressure gradient (HVPG) was performed after 8 wk.
RESULTS:  One patient in the propranolol/irbesartan group was excluded due to variceal bleeding. No other adverse events occurred. Portal pressure declined in both groups (propranolol/irbesartan group 19.6 ± 1.5 mmHg to 16.6 ± 1.2 mmHg, P = 0.037, propranolol/placebo group 17.8 ± 1.1 mmHg to 15.1 ± 1.2 mmHg, P = 0.019). Sodium excretion significantly increased in the propranolol/irbesartan group (from 122 ± 20 mmol/d to 230 ± 23 mmol/d, P = 0.045), but not in the propranolol/placebo group.
CONCLUSIONS:  Combination treatment of propranolol plus irbesartan is well tolerated in cirrhotic patients when titrating the angiotensin II antagonist in a step-up manner, and it increases sodium excretion in patients with compensated or moderately decompensated cirrhosis. Addition of irbesartan has no effect on portal pressure.     

Treatment with irbesartan or atenolol improves endothelial function in essential hypertension

OBJECTIVES: To investigate if antihypertensive treatment could improve endothelium-dependent vasodilatation in hypertensive patients, and whether the angiotensin II subtype-1 (AT1)-receptor antagonist irbesartan and the beta1-receptor antagonist atenolol would differ in this respect. SUBJECTS AND METHODS: Thirty-four patients (28 men and six women) with mild-to-moderate essential hypertension (diastolic blood pressure 90-120 mmHg) were randomized to once daily 150-300 mg irbesartan or 50-100 mg atenolol in a double-blind fashion, preceded by a placebo run-in period. Forearm blood flow (FBF) was assessed by venous occlusion plethysmography during local intra-arterial infusions of methacholine and sodium nitroprusside, to evaluate endothelium-dependent and endothelium-independent vasodilatation, respectively. Measurements of FBF were undertaken at the end of the run-in placebo period and repeated after 3 months of active antihypertensive treatment. RESULTS: Irbesartan and atenolol induced a similar decline in blood pressure (from 171/107 to 158/98 mmHg, P < 0.05), and improved endothelium-dependent vasodilatation (e.g. an increase in FBF response to 4 microg/min methacholine from 325 +/- 29% to 411 +/- 41%, P < 0.05), with no difference between the two study drugs. No significant changes in endothelium-independent vasodilatation were induced by irbesartan or by atenolol. CONCLUSIONS: The present study shows that 3 months of antihypertensive therapy with irbesartan or atenolol improves endothelium-dependent vasodilatation.     

Carvedilol action is dependent on endogenous production of nitric oxide

BACKGROUND: Carvedilol is known to be an adrenoreceptor blocker and free radical scavenger, used in hypertension and cardiac failure. However, its therapeutic actions cannot be fully explained by these mechanisms. In these studies, we tested the hypothesis that carvedilol action is associated with the synthesis/release of nitric oxide (NO). METHODS: Male Wistar rats (n = 22), 9 weeks old, were anesthetized with an intraperitoneal injection of sodium pentobarbital. Mean arterial pressure and arterial NO levels were monitored throughout the experiments. Carvedilol (1 mg/kg, intravenously [iv]) effects were evaluated before and after NO synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME, 5 mg/kg, iv). RESULTS: Carvedilol induced a significant decrease in basal arterial pressure (from 126.6 +/- 4.3 mm Hg to 75.9 +/- 3.0 mm Hg, P < .001) and significant increase in NO levels (from 17.9 +/- 1.7 micromol/L to 32.2 +/- 2.5 micromol/L, P < .001). After administration of L-NAME the arterial pressure increased (129.9 +/- 5.0 mm Hg, P < .001) with concomitant decrease in NO levels (13.4 +/- 1.6 micromol/L, P < .01). The second carvedilol administration (post-L-NAME) did not affect either arterial pressure (108.3 +/- 8.0 mm Hg) or NO levels (22.1 +/- 1.3 micromol/L). CONCLUSIONS: Our results suggest that the carvedilol-induced decrease of blood pressure is associated with an increase of plasma NO levels. Furthermore, NOS inhibition results in impairment of carvedilol hemodynamic effects and plasma NO levels. Therefore, these results are consistent with the hypothesis that the hemodynamic effect of carvedilol is in part dependent on endogenous NO production.     

Long-term arterial pressure in spontaneously hypertensive rats is set by the kidney.

OBJECTIVES: We investigated whether arterial pressure in spontaneously hypertensive rats (SHR) can be normalized by a kidney graft from normotensive histocompatible donors. In addition, the effect of differential genetic predisposition to hypertension of recipients of an SHR kidney on the development of post-transplantation hypertension was studied. METHODS: SHR were transplanted with a kidney from congenic rats (BB.1K) homozygous for a 2 cM segment of SHR chromosome 20, including the major histocompatibility complex class Ia and class II genes. BB.1K and F1 hybrids (F1H, SHR x Wistar-Kyoto rats) were transplanted with an SHR kidney and the development of renal post-transplantation hypertension was monitored. RESULTS: Thirty days after renal transplantation, mean arterial pressure (MAP) was 116 +/- 4 mmHg in SHR with a BB.1K kidney (n = 8) versus 168 +/- 2 mmHg in sham-operated SHR (n = 10); P < 0.001. Cumulative renal sodium balance (mmol/100 g body weight) over 21 days after bilateral nephrectomy was 6.8 +/- 0.6 in SHR with a BB.1K kidney versus 10.8 +/- 1.6 in sham-operated SHR (P < 0.05). Within 60 days of transplantation, MAP increased in BB.1K and in F1H transplanted with an SHR kidney (n = 7 per group) by 38 +/- 5 mmHg and 43 +/- 8 mmHg, respectively. CONCLUSIONS: In SHR, arterial pressure can be normalized by a kidney graft from normotensive donors. The genetic predisposition of the recipients to hypertension does not modify the rate and the extent of the arterial pressure rise induced by an SHR kidney graft.     

Safety of the combination of valsartan and benazepril in patients with chronic renal disease. European Group for the Investigation of Valsartan in Chronic Renal Disease

OBJECTIVE: Several experimental and clinical studies indicate that the renin system may play a pivotal role in progressing renal disease. The combination of an angiotensin-converting enzyme inhibitor and an angiotensin receptor blocker could provide a higher degree of blockade of the renin-angiotensin system than either agent alone. Such enhanced suppression might be of benefit for patients exhibiting a progressive decline in renal function because of chronic renal disease. METHODS: A pilot multinational, multicentre, randomized, active-controlled, parallel group open-label study has been conducted in a group of patients with progressive chronic renal failure (creatinine clearance 20-45 ml/min) either with or without proteinuria and hypertension. The primary aim of the study was to investigate the safety and tolerability of the combination of valsartan and benazepril. Patients were randomly assigned to one of three groups: group 1 received valsartan 160 mg once daily (n = 22); group 2 received valsartan 80 mg once daily plus benazepril 5 or 10 mg once daily (n = 42); group 3 received valsartan 160 mg once daily plus benazepril 5 or 10 mg once daily (n = 44). The study lasted for 5 weeks, and in groups 2 and 3 benazepril was added on top of valsartan after the first week of therapy with the angiotensin receptor blocker. RESULTS: Serum creatinine increased in all three groups (mean change within a group: 11 micromol/l in group 1, P= 0.045; 9 micromol/l in group 2, P= 0.030; 15 micromol/l in group 3, P= 0.0006). Serum potassium also increased in all three groups of patients (mean change within a group: 0.28 mmol/l in group 1, P= 0.28; 0.48 mmol/l in group 2, P= 0.0008; 0.36 mmol/l in group 3, P= 0.02). After 5 weeks of treatment, the largest decrease in blood pressure was observed in group 3 (the mean change from baseline in seated diastolic blood pressure (SDBP) and seated systolic blood pressure (SSBP), respectively, were: -2.0 and -11.5 mmHg in group 1; -7.6 and -15.4 mmHg in group 2; -12.6 and -21.6 mmHg in group 3). In addition, both combination treatments resulted in the reduction of proteinuria. The total number of patients with adverse experiences were 10 (45.5%), 14 (33.3%) and 11 (25%) in groups 1,2 and 3, respectively. In six patients (5.6%) therapy was discontinued as a result of adverse experiences. Only one patient in each of the combined therapy groups withdrew from the study because of hyperkalaemia and no patients were forced to withdraw because of an increase in serum creatinine, acute renal failure or hospitalization. CONCLUSIONS: These results indicate that short-term combination of an angiotensin-converting enzyme inhibitor and an angiotensin receptor blocker is safe and well tolerated in patients with moderate chronic renal failure.