The protective effect of HMG-CoA reductase inhibitors against monocrotaline-induced pulmonary hypertension in the rat might not be a class effect: comparison of pravastatin and atorvastatin

Hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, so called statins, improve endothelial function and exert antiproliferative effects on vascular smooth muscle cells of systemic vessels. This study aimed at comparing the protective effects of two statins, pravastatin and atorvastatin, against monocrotaline (MC)-induced pulmonary hypertension in rats. Pravastatin or atorvastatin (PS or AS, 10 mg/kg per day) or vehicle were given orally for 28 days to Wistar male rats injected or not with MC (60 mg/kg intraperitoneally). At 4 weeks, MC-injected rats developed severe pulmonary hypertension, with an increase in right ventricular pressure (RVP) and right ventricle/left ventricle + septum weight ratio associated with a decrease in acetylcholine- or sodium-nitroprusside-induced pulmonary artery dilation observed in vitro. Hypertensive pulmonary arteries exhibited an increase in medial thickness and endothelial cell apoptosis and a decrease of endothelial nitric oxide synthase (eNOS) expression. MC-rat lungs showed a significant decrease of eNOS (P < 0.01) and increase of cleaved caspase-3 (P < 0.05) expression determined by Western blotting. PS (P = 0.02) but not AS (P = 0.30) significantly limited the development of pulmonary hypertension (RVP in mmHg: 30 ± 3, 36 ± 4 vs. 45 ± 4 and 14 ± 1 for MC + PS, MC + AS, MC, and control groups, respectively). Both statins significantly reduced MC-induced right ventricle hypertrophy [RV/left ventricular (LV) + S, in mg/g: 0.46 ± 0.04, 0.39 ± 0.03, 0.62 ± 0.05 and 0.29 ± 0.01 for MC + PS, MC + AS, MC, and control groups, respectively; P < 0.05),and reduced MC-induced thickening (61 ± 6 μm, 82 ± 5 μm, 154 ± 4 μm, and 59 ± 2 μm for MC + PS, MC + AS, MC, and control groups, respectively; P = 0.01) of small intrapulmonary artery medial wall, with MC + AS still being different from the control group. PS but not AS partially restored acetylcholine-induced pulmonary artery vasodilation in MC rats (E_max=65 ± 5%, 49 ± 6%, 46 ± 3%, and 76 ± 4% for MC + PS, MC + AS, MC, and control groups, respectively; P < 0.05 for MC + PS vs. other groups). Both statins prevented apoptosis and restored eNOS expression of pulmonary artery endothelial cells as well as in the whole lung with a more pronounced effect with PS compared with AS. In conclusion, despite its effects on eNOS expression, apoptosis, and medial wall thickening, AS was unable to significantly reduce pulmonary hypertension and to restore endothelium-dependent relaxation, suggesting intermolecular differences between the two HMG-CoA reductase inhibitors in the protection against MC-induced hypertension.     

Celecoxib but not the combination of celecoxib+atorvastatin prevents the development of monocrotaline-induced pulmonary hypertension in the rat

The present study aimed to assess the effects of a COX-2 inhibitor, celecoxib, a HMG-CoA reductase inhibitor, atorvastatin, and the association of both on monocrotaline (MC)-induced pulmonary hypertension in rats. Celecoxib (Cib, 25 mg kg(-1) day(-1)), atorvastatin (AS, 10 mg kg(-1) day(-1)) or vehicle, were given orally, separately or in combination, for 26 days to Wistar male rats injected or not with MC (60 mg/kg intraperitoneally). At 4 weeks, MC-injected rats developed a severe pulmonary hypertension, with an increase in lung to body weight ratio (L/BW), right ventricular pressure (RVP in mmHg, 31 +/- 3 and 14 +/- 1 for MC and control groups, respectively, P < 0.05) and right ventricle/left ventricle + septum weight ratio (RV/LV+S) associated with a decrease in acetylcholine- and sodium-nitroprusside-induced pulmonary artery vasodilation in vitro. Hypertensive pulmonary arteries exhibited an increase in wall thickness (wall thickness to external diameter ratio, 0.42 +/- 0.01 vs 0.24 +/- 0.01 for MC and control groups, respectively, P < 0.001). Whole lung eNOS expression was decreased, and an increase in apoptosis, evaluated by cleaved caspase-3 expression, was evidenced by Western blotting. Cib (RVP in mmHg, 19 +/- 3 and 31 +/- 3 for MC+Cib and MC groups, respectively, P < 0.05), but neither AS nor AS+Cib significantly limited the development of pulmonary hypertension (P < 0.05), although the three treatments exhibited protective effects against MC-induced lung and right ventricle hypertrophy evaluated by L/BW and RV/(LV+S) ratios, respectively (P < 0.05). AS, Cib and AS+Cib treatments reduced MC-induced thickening of small intrapulmonary artery wall (0.42 +/- 0.01, 0.24 +/- 0.01, 0.26 +/- 0.01 and 0.28 +/- 0.01 for MC, MC+AS, MC+Cib and MC+AS+Cib groups, respectively, P < 0.001). In control rats, Cib reduced acetylcholine-induced pulmonary artery vasorelaxation. Treatment of MC rats by either Cib or AS did not modify acetylcholine-induced pulmonary artery relaxation, whereas combination of both drugs significantly worsened it (P < 0.05). AS, but neither Cib nor the combination of both, prevented apoptosis (AS, P < 0.05) and partially restored eNOS expression (AS, P < 0.05) in whole lung of MC rats. In conclusion, celecoxib exhibited beneficial effects against the development of monocrotaline-induced pulmonary artery hypertension and right ventricular hypertrophy. These beneficial effects of celecoxib might be, at least partly, explained by its effects on pulmonary artery thickening and pulmonary hypertrophy, even if it did not show any effect on pulmonary artery vasorelaxation and whole lung eNOS expression or apoptosis. The combination of celecoxib and atorvastatin was unable to prevent MC-induced pulmonary hypertension, decreased endothelium-dependent vasorelaxation and showed a trend toward an increased in RVP that deserves further studies.     

Rosuvastatin attenuates monocrotaline-induced pulmonary hypertension via regulation of Akt/eNOS signaling and asymmetric dimethylarginine metabolism

This study was designed to investigate whether rosuvastatin could attenuate monocrotaline-induced pulmonary hypertension via regulation of Akt/eNOS signaling pathway and asymmetric dimethylarginine (ADMA) metabolism in rats. After a single-dose injection of monocrotaline (60 mg/kg), oral administration of rosuvastatin (5mg/kg) was started from day 1 to day 28 (preventive administration) or from day 15 to day 28 (therapeutic administration), or with vehicle as corresponding controls. 28 days after monocrotaline, significant pulmonary hypertension characterized by pulmonary arterial medial wall thickening, right ventricular hypertrophy and right heart failure was observed. Rosuvastatin (5mg/kg, for 14 days and 28 days) treatment significantly attenuated monocrotaline-induced pulmonary vascular remodeling, right ventricular hypertrophy and dysfunction, and normalized the down-regulated pulmonary Akt/p-Akt and eNOS/p-eNOS expressions, while increased DDAH2 expression accompanied by decreased serum level of ADMA. However expression of PRMT1 and GSK3β/p-GSK3β did not differ among all groups (all P>0.05). We concluded that rosuvastatin inhibits monocrotaline-induced pulmonary hypertension through normalization of Akt, eNOS and DDAH2 expressions, and decreasing the level of ADMA.     

Tetrahydrobiopterin analogues with NO-dependent pulmonary vasodilator properties

Reduced NO levels due to the deficiency of tetrahydrobiopterin (BH₄) contribute to impaired vasodilation in pulmonary hypertension. Due to the chemically unstable nature of BH₄, it was hypothesised that oxidatively stable analogues of BH₄ would be able to support NO synthesis to improve endothelial dysfunction in pulmonary hypertension. Two analogues of BH₄, namely 6-hydroxymethyl pterin (HMP) and 6-acetyl-7,7-dimethyl-7,8-dihydropterin (ADDP), were evaluated for vasodilator activity on precontracted rat pulmonary artery rings. ADDP was administered to pulmonary hypertensive rats, followed by measurement of pulmonary vascular resistance in perfused lungs and eNOS expression by immunohistochemistry. ADDP and HMP caused significant relaxation in vitro in rat pulmonary arteries depleted of BH₄ with a maximum relaxation at 0.3 μM (both P < 0.05). Vasodilator activity of ADDP and HMP was completely abolished following preincubation with the NO synthase inhibitor, L-NAME. ADDP and HMP did not alter relaxation induced by carbachol or spermine NONOate. BH₄ itself did not produce relaxation. In rats receiving ADDP 14.1 mg/kg/day, pulmonary vasodilation induced by calcium ionophore A23187 was augmented and eNOS immunoreactivity was increased. In conclusion, ADDP and HMP are two analogues of BH₄, which can act as oxidatively stable alternatives to BH₄ in causing NO-mediated vasorelaxation. Chronic treatment with ADDP resulted in improvement of NO-mediated pulmonary artery dilation and enhanced expression of eNOS in the pulmonary vascular endothelium. Chemically stable analogues of BH₄ may be able to limit endothelial dysfunction in the pulmonary vasculature.     

L-精氨酸治疗缺氧性肺动脉高压

目的 :探讨L -精氨酸 (L -Arg)干预缺氧性肺血管结构重建的机制。方法 :将18只Wistar大鼠采用随机设计分为对照组、缺氧组和缺氧 +L -Arg组 (共6个配伍组 )。以右心导管法测定肺动脉压力 ,并对大鼠肺组织标本进行显微结构观察和超微结构观察 ,同时以免疫组化方法分析肺动脉I型胶原表达。结果 :缺氧组大鼠肺动脉平均压 (mPAP)为 (2 7±0 3)kPa ,对照组为 (2 1±0 1)kPa ,两者比较 ,P<0 05。缺氧组大鼠肺血管显微及超微结构发生明显改变 ,有肺血管结构重建形成。然而 ,缺氧 +L -Arg组大鼠mPAP为 (2 2±0 2)kPa ,缺氧组为 (2 7±0 3)kPa ,两者比较 ,P<0 05。L -Arg缓解了缺氧性肺血管结构重建的形成。结论 :L -Arg 对缺氧性肺血管结构重建以及缺氧性肺动脉高压的形成有重要的调节作用     

Immunosuppression with mycophenolate mofetil attenuates the development of hypertension and albuminuria in deoxycorticosterone acetate‐salt hypertensive rats

1. The interplay between the immune and renin–angiotensin systems is emerging as a crucial factor in the development and progression of hypertension. The aim of the present study was to determine the involvement of immune cells in the hypertension and renal injury produced by a non‐angiotensin II‐dependent form of hypertension, namely deoxycorticosterone acetate (DOCA)‐salt‐induced hypertension, in rats. 2. Male Sprague‐Dawley rats underwent uninephrectomy and received either a sustained‐release pellet of DOCA s.c. and 0.9% NaCl (saline) to drink for 21 days or a placebo pellet and water to drink for 21 days. Additional groups of DOCA‐salt‐ and placebo‐treated rats were treated concurrently with the immune suppressant mycophenolate mofetil (MMF; 30 mg/kg per day). Rats were placed in metabolic cages for 24 h urine collection prior to and at weekly intervals during the 21 day experimental period. 3. Mycophenolate mofetil significantly attenuated the development of hypertension in DOCA‐salt rats compared with untreated DOCA‐salt hypertensive rats (mean arterial pressure by telemetry on Day 18 146 ± 7 vs 180 ± 3 mmHg, respectively; P < 0.001), as well as proteinuria (87 ± 27 vs 305 ± 63 mg/day, respectively, on Day 21) and albuminuria (51 ± 15 vs 247 ± 73 mg/day, respectively, on Day 21). Creatinine clearance was better preserved in MMF‐treated DOCA‐salt rats compared with untreated DOCA‐salt rats (0.74 ± 0.07 vs 0.49 ± 0.09 mL/min, respectively; P < 0.05), but was still significantly reduced compared with that in the placebo group (1.15 ± 0.12 mL/min; P < 0.05). Finally, MMF treatment significantly attenuated the DOCA‐salt‐induced rise in renal cortical T‐lymphocyte and macrophage infiltration (P < 0.05). 4. These data indicate that immune cells play a deleterious role in both the hypertension and renal injury associated with DOCA‐salt hypertension.     

低氧大鼠肺内TSP-1与EGFR的表达变化及意义

摘要 目的 了解低氧肺动脉高压时肺内凝血酶敏感蛋白-1（TSP-1）和表皮生长因子受体（EGFR）表达与肺血管重建的关系。 方法 将20只雄性Wistar大鼠分为低氧性肺动脉高压组（n=10）和对照组（n=10）两组,肺动脉高压组以常压低氧建立大鼠肺动脉高压模型,以微导管法测定各组大鼠肺动脉压,采用免疫组化和原位杂交法检测各组大鼠肺内TSP-1蛋白、EGFR蛋白及TSP-1mRNA、EGFRmRNA的表达,对肺组织切片进行图象分析。 结果 低氧3周后,低氧组大鼠形成明显的肺动脉高压,管壁增厚和管腔狭窄,低氧组大鼠肺动脉压（2.86±0.39）kP,右心室肥厚指数﹝RV/(LV+S)﹞为43.53±3.38、管壁厚度占外径的百分比（WT%）为35.24±11.2,管壁面积占血管总面积的百分比（WA％）为55.09±12.38,分别与正常对照组(1.35±0.28)kP、23.68±3.48、23.63±9.74和41.62±12.83相比明显升高（P<0.01）;肺小动脉TSP-1免疫阳性染色在低氧肺动脉高压组大鼠为1.32±0.04,与正常对照组（0.96±0.03）相比增强（P<0.01）,低氧肺动脉高压组大鼠EGFR蛋白免疫染色为1.48±0.07,与正常对照组（1.09±0.02）相比增强（P<0.01）。肺小动脉TSP-1mRNA阳性染色在低氧组大鼠为1.44±0.03,与正常对照组1.12±0.05相比明显增强（P<0.01）,低氧组大鼠EGFRmRNA阳性染色为1.43±0.05,与正常对照组1.10±0.04相比明显增强（P<0.01）。 结论 低氧所致TSP-1及EGFR增多在低氧性肺血管重建和肺动脉高压的发病过程中起一定的作用。     

氟伐他汀对野百合碱所致的大鼠肺血管重塑和右心室肥厚的影响

目的观察氟伐他汀对野百合碱(MCT)所致的大鼠肺血管重塑和右心室肥厚的影响。方法66只大鼠被随机分为3组:(1)M+F组(n=24):本组大鼠首先给予每日1次MCT(60mg/kg)皮下注射,连续2周,第3周至第6周末给予氟伐他汀(1mg/kg)灌胃,每日1次。(2)MCT组(n=24):实验前2周给予每日1次MCT(60mg/kg)皮下注射,第3周至第6周末给予与氟伐他汀等体积的0.9盐水灌胃;(3)Saline组(n=18):分别于实验前2周及第2周末至第6周末给予等体积的0.9盐水皮下注射和灌胃。MCT注射前记为第0周,实验共观察6周。分别于不同时间点观察大鼠肺组织形态学变化,并对平均肺动脉压(mPAP)、管壁厚度百分比(PWT)、右心室肥厚指数(RVHI)进行测定。结果MCT注射2周后,大鼠出现显著的肺血管重塑和右心室肥厚,MCT组大鼠在MCT停止注射后mPAP、PWT及RVHI进一步增高。而M+F组大鼠在给予连续4周氟伐他汀1mg/(kg.d)灌胃处理后,mPAP(23.3±3.2)mmHg及PWT(42.3±2.7)均较MCT组减轻。RVHI(0.32±0.02)亦较MCT组(0.54±0.03)显著降低,且与正常对照组(Saline组)比较无显著差异。结论氟伐他汀能有效减轻MCT诱导的大鼠肺血管重塑和右心室肥厚。     

The xanthine derivative KMUP-1 inhibits models of pulmonary artery hypertension via increased NO and cGMP-dependent inhibition of RhoA/Rho kinase

Background and purpose:

KMUP-1 is known to increase cGMP, enhance endothelial nitric oxide synthase (eNOS) and suppress Rho kinase (ROCK) expression in smooth muscle. Here, we investigated the mechanism of action of KMUP-1 on acute and chronic pulmonary artery hypertension (PAH) in rats.

Experimental approach:

We measured pulmonary vascular contractility, wall thickening, eNOS immunostaining, expressions of ROCK II, RhoA activation, myosin phosphatase target subunit 1 (MYPT1) phosphorylation, eNOS, soluble guanylyl cyclase (sGC), protein kinase G (PKG) and phosphodiesterase 5A (PDE-5A), blood oxygenation and cGMP/cAMP, and right ventricular hypertrophy (RVH) in rats.

Key results:

In rings of intact pulmonary artery (PA), KMUP-1 relaxed the vasoconstriction induced by phenylephrine (10 µM) or the thromboxane A₂-mimetic U46619 (0.5 µM). In endothelium-denuded PA rings, this relaxation was reduced. In acute PAH induced by U46619 (2.5 µg·kg⁻¹·min⁻¹, 30 min), KMUP-1 relaxed vasoconstriction by enhancing levels of eNOS, sGC and PKG, suppressing those of PDE-5A, RhoA/ROCK II activation and MYPT1 phosphorylation, and restoring oxygenation in blood and cGMP/cAMP in plasma. Incubating smooth muscle cells from PA (PASMCs) with KMUP-1 inhibited thapsigargin-induced Ca²⁺ efflux and angiotensin II-induced Ca²⁺ influx. In chronic PAH model induced by monocrotaline, KMUP-1 increased eNOS and reduced RhoA/ROCK II activation/expression, PA wall thickening, eNOS immunostaining and RVH. KMUP-1 and sildenafil did not inhibit monocrotaline-induced PDE-5A expression.

Conclusion and implications:

KMUP-1 decreased PAH by enhancing NO synthesis by eNOS, with consequent cGMP-dependent inhibition of RhoA/ROCK II and Ca²⁺ desensitization in PASMCs. KMUP-1 has the potential to reduce vascular resistance, remodelling and RVH in PAH.     

Liraglutide improves obesity-induced renal injury by alleviating uncoupling of the glomerular VEGF–NO axis in obese mice

Obesity-related kidney disease is associated with generalized endothelial dysfunction. Liraglutide, a glucagon-like peptide-1 agonist, has cardiovascular–renal protective effects in patients with diabetes. In this study, the ability of liraglutide to reduce urinary albumin excretion by alleviating glomerular vascular endothelial growth factor-nitric oxide (VEGF–NO) axis uncoupling was assessed in high fat diet-induced obese mice. C57BL/6J mice were divided into control and obesity groups, treated with or without liraglutide (200 μg/kg/day). Blood biochemistry and urinary albumin excretion were measured. Glomerular VEGF and the AMPK–endothelial nitric oxide synthase (eNOS) pathway were assayed by western blotting. Glomerular NO, renal haeme oxygenase-1 activity, and malondialdehyde levels were also measured. Treatment of obese mice with liraglutide led to significant reductions in body weight gain (46 ± 1 g vs 55 ± 1 g, P < .0001), visceral fat (8.9 ± 0.6 g vs 14.5 ± 0.6 g, P < .0001), perirenal fat (2.9 ± 0.2 g vs 5.4 ± 0.3 g, P < .0001), and free fatty acid (1.71 ± 0.12 mmol/L vs 1.02 ± 0.08 mmol/L, P < .0001). Liraglutide significantly improved glucose homeostasis, which was impaired in obese mice. Liraglutide reduced urinary albumin excretion and glomerular hypertrophy in obese mice. Additionally, liraglutide significantly decreased VEGF and increased glomerular NO production in glomeruli, indicating restoration of the glomerular VEGF–NO axis. Furthermore, liraglutide activated the glomerular AMPK–eNOS pathway in obese mice, upregulated renal haeme oxygenase-1 activity, and reduced the renal malondialdehyde levels in obese mice. In conclusion, liraglutide reduced microalbuminuria and ameliorated renal injury by alleviating the uncoupling of the glomerular VEGF–NO axis.     

Protective role of the antidiabetic drug metformin against chronic experimental pulmonary hypertension

Background and purpose:

Pulmonary arterial hypertension (PAH) is associated with increased contraction and proliferation of pulmonary vascular smooth muscle cells. The anti-diabetic drug metformin has been shown to have relaxant and anti-proliferation properties. We thus examined the effect of metformin in PAH.

Experimental approach:

Metformin effects were analysed in hypoxia- and monocrotaline-induced PAH in rats. Ex vivo and in vitro analyses were performed in lungs, pulmonary artery rings and cells.

Key results:

In hypoxia- and monocrotaline-induced PAH, the changes in mean pulmonary arterial pressure and right heart hypertrophy were nearly normalized by metformin treatment (100 mg·kg⁻¹·day⁻¹). Pulmonary arterial remodelling occurring in both experimental models of PAH was also inhibited by metformin treatment. In rats with monocrotaline-induced PAH, treatment with metformin significantly increased survival. Metformin increased endothelial nitric oxide synthase phosphorylation and decreased Rho kinase activity in pulmonary artery from rats with PAH. These effects are associated with an improvement of carbachol-induced relaxation and reduction of phenylephrine-induced contraction of pulmonary artery. In addition, metformin inhibited mitogen-activated protein kinase activation and strongly reduced pulmonary arterial cell proliferation during PAH. In vitro, metformin directly inhibited pulmonary artery smooth muscle cell growth.

Conclusions and implications:

Metformin protected against PAH, regardless of the initiating stimulus. This protective effect may be related to its anti-remodelling property involving improvement of endothelial function, vasodilatory and anti-proliferative actions. As metformin is currently prescribed to treat diabetic patients, assessment of its use as a therapy against PAH in humans should be easier.     

The promising effect of barberry (Zereshk) extract against experimental pulmonary microvascular remodeling and hypertension: A comparison with sildenafil

Context: Despite the beneficial effects of barberry (Berberis integerrima Berberidaceae) on decreasing systemic hypertension, its influence has not been investigated on pulmonary hypertension.

Objective: The objective of this study is to examine the effect of barberry fruit, on monocrotaline-induced pulmonary hypertension.

Materials and methods: Nine groups were arranged as follows: the control group, the monocrotaline (M) group, the barberry groups with doses of 50, 100, and 200 (mg/kg), the M plus barberry groups, and the M plus sildenafil group. Two weeks after a single injection of monocrotaline (60?mg/kg, s.c.), barberry water extracts or sildenafil (30?mg/kg/d) were gavaged daily for 2 weeks. At the end of the 4th week, hemodynamic, biochemical, and histopathological parameters were assessed.

Results: In comparison with the M group, barberry (200?mg/kg) or sildenafil significantly reduced the right ventricular systolic pressure (RVSP) (22.95?±?1.78?mm Hg and 30.71?±?1.64?mm Hg, versus 41.28?±?1.5?mm Hg), right ventricular hypertrophy (RVH) (0.39?±?0.03 and 0.42?±?0.02, versus 0.57?±?0.02), and the medial wall thickness (MWT) (4.56?±?0.15?µm and 5.97?±?0.19?µm, versus 7.02?±?0.43?µm). Barberry or sildenafil had no significant effect on the plasma level of endothelin-1, glutathione peroxidase, and the malondialdehide of lung.

Conclusion: 200?mg/kg of barberry has an improving effect on the monocrotaline-induced pulmonary hypertension. This effect was stronger than that of the sildenafil's and may have been mediated through mechanisms other than the modulation of the endothelin-1 or redox system.     

2-methoxyestradiol attenuates bleomycin-induced pulmonary hypertension and fibrosis in estrogen-deficient rats

Pulmonary hypertension (PH) is a common and life-threatening complication of pulmonary fibrosis. Estradiol (E2) is protective in experimental PH, and its non-estrogenic metabolite 2-methoxyestradiol (2ME) prevents the development and retards the progression of monocrotaline-induced PH in male and female rats. However, the effects of E2 and 2ME on pulmonary fibrosis and associated PH have not been examined. Therefore, we compared the growth inhibitory effects of E2 and 2ME in human lung fibroblasts (hLFs) and pulmonary vascular smooth muscle cells (hPASMCs), and we investigated the effects of estrogen deficiency and 2ME on bleomycin-induced pulmonary fibrosis and PH. Intact and ovariectomized (OVX) female Sprague–Dawley rats were administered intratracheally either saline or bleomycin (15 IU/kg), and a subset of OVX bleomycin-treated rats received 2ME (10 μg/kg/h) for 21 days. Estradiol had only limited inhibitory effects on growth in hPASMCs and no effect in hLFs, whereas 2ME exhibited strong and concentration-dependent (1–10 μM) antimitogenic effects in both cell types. Bleomycin caused lung injury/PH (significantly increased lung and right ventricle (RV) weights, RV peak systolic pressure (RVPSP), and RV/left ventricle + septum ratio (RV/LV + S); caused medial hypertrophy and adventitial widening of pulmonary arteries; induced marked focal/diffuse fibrosis with diffuse infiltration of inflammatory (ED1+) cells; and resulted in 30% mortality). OVX exacerbated the disease and increased mortality (to 75%); whereas 2ME tended to reduce mortality (55.5%) and in surviving animals reduced RVPSP and RV/LV + S ratio, and attenuated vascular remodeling, pulmonary inflammation and fibrosis. This study suggests that 2ME may have protective effects in bleomycin-induced PH and fibrosis. Further investigation of 2ME in pulmonary fibrosis and PH is warranted.     

The impact of daily sildenafil on levels of soluble molecular markers of endothelial function in plasma in patients with erectile dysfunction

Objective: To investigate the impact of daily sildenafil on levels of soluble molecular markers of endothelial function in men with erectile dysfunction. Methods: Patients aged > 18 years with erectile dysfunction of vascular etiology for > 6 months, either alone or in combination with disease states strongly associated with endothelial dysfunction such as diabetes/metabolic syndrome, hypertension and coronary artery disease, received sildenafil 25 mg orally for 4 weeks. Markers of endothelial function were measured in plasma at baseline and at end of treatment using standard methods and commercially available kits. Results: Altogether, 112 men with mean (SD) age of 60.6 (7.3) years completed the protocol. Sildenafil 25 mg daily for 4 weeks significantly reduced endothelin-1 levels compared with baseline (2.83 ± 1.63 vs 3.24 ± 1.90 pg/ml, p < 0.001). Significant changes were also observed for nitric oxide (35.12 ± 21.14 vs 31.91 ± 16.28 pmol/lt, p = 0.01) and cyclic guanosine monophosphate (3.79 ± 2.37 vs 2.70 ± 1.34 pmol/ml, p < 0.001) levels, but not for any of the other biomarkers measured. Erectile function was significantly improved. Conclusions: Daily sildenafil ameliorates endothelial function as assessed by levels of biomarkers of endothelial function in patients with erectile dysfunction. This is in agreement with other studies showing similar benefits with phosphodiesterase-5 inhibitor treatment. The clinical implications of this finding warrant further investigation.     

Intravenous administration of pravastatin immediately after middle cerebral artery occlusion reduces cerebral oedema in spontaneously hypertensive rats

3-hydroxy-3-methyl-glutaryl-coenzyme-A (HMG-CoA) reductase inhibitors (statins) have been shown to protect against ischemic stroke by mechanisms that are independent of lowering serum cholesterol levels. In this study we investigated the potential neuroprotective effect of a single i.v. treatment with four increasing doses of pravastatin on permanent occlusion of middle cerebral artery (MCAo) in spontaneously hypertensive rats. Pravastatin was given 10 min after MCAo and its effect was determined 24 h later. Treatment results were evaluated in terms of infarct volume, homolateral hemisphere oedema, glial fibrillary acid (GFAP), vimentin (Vim) and endothelial NO synthase (eNOS) immunoreactivity and TUNEL positivity. Cerebral levels of eNOS were measured by western blot analysis. Pravastatin did not reduce cerebral infarct while it mitigated homolateral hemisphere oedema in a dose-dependent manner with respect to controls. No differences among groups were found regarding GFAP and Vim immunoreactivity and TUNEL positivity. Instead, pravastatin-treated animals presented a more marked cerebral eNOS immunoreactivity as compared with controls. In agreement with immunohistochemistry, immunoblot revealed dose-dependent increases in cerebral levels of eNOS in pravastatin rats. Our data confirm statin neuroprotection in cerebral ischemia. In particular, it is of great interest that a single i.v. Pravastatin administration reduced cerebral oedema by upregulating eNOS expression/activity. This, by increasing vascular NO bioavailability, could have produced proximal vasodilation and contributed to reducing perfusional deficit. It is worthy stressing how important the anti-oedema action is that pravastatin seems to exert. Indeed, cerebral oedema, when widespread and beyond limits of physiological compensation, causes endocranic hypertension and additional cerebral damage over time.     

黄芪多糖对野百合碱诱导大鼠肺动脉高压的减缓作用及其机制研究

目的研究黄芪多糖对野百合碱诱导大鼠肺动脉高压的减缓作用及可能机制。方法将100只SD雄性大鼠随机分为正常对照组、野百合碱组、黄芪多糖低剂量组和黄芪多糖高剂量组。除正常对照组外,其余组大鼠按60 mg/kg单次腹腔注射野百合碱。黄芪多糖低剂量组及高剂量组大鼠在给药后的第2~28天分别按200 mg/kg及400 mg/kg腹腔注射黄芪多糖,每日1次。每组25只大鼠各取15只进行研究,检测各组大鼠平均肺动脉压(mPAP)、右心肥厚指数(RVHI),观察其肺动脉及心肌细胞形态变化,检测其肺组织中白细胞介素17(IL-17)mRNA及蛋白的表达水平。结果与正常对照组比较,野百合碱组及黄芪多糖各剂量组大鼠mPAP、RVHI均显著升高(P<0.01),肺组织中IL-17的mRNA和蛋白表达水平均显著升高(P<0.01),肺动脉及心肌细胞有明显病理改变;与野百合碱组比较,黄芪多糖各剂量组大鼠mPAP、RVHI均显著降低(P<0.01),肺组织中IL-17的mRNA和蛋白表达水平均显著降低(P<0.01),肺动脉及心肌细胞病理变化有改善;与黄芪多糖低剂量组比较,黄芪多糖高剂量组大鼠上述指标水平及病理改变的改善更明显。结论黄芪多糖能降低野百合碱诱导大鼠的肺动脉高压,并改善肺动脉结构及心肌病理改变,推测其机制可能与下调大鼠肺组织中IL-17的表达有关。     

Evaluation of olmesartan medoxomil in the rat monocrotaline model of pulmonary hypertension

It is suggested that angiotensin II is involved in the pathogenesis of pulmonary hypertension and subsequent right ventricular hypertrophy; therefore, an angiotensin AT1 receptor antagonist could be beneficial for the treatment of this disease. We tested the effect of the new AT1 receptor antagonist olmesartan medoxomil on monocrotaline-induced pulmonary hypertension in rats. At 3 weeks after a single subcutaneous injection of monocrotaline (50 mg/kg), the lung/body weight ratio, the right ventricle/(left ventricle plus septum) weight ratio [RV/(LV+S)], and right ventricular systolic pressure were increased, indicating establishment of pulmonary hypertension and right ventricular hypertrophy. Oral administration of olmesartan medoxomil (2 or 5 mg/kg/day for 3 weeks) restored RV/(LV+S) and right ventricular systolic pressure, and a higher dose (5 mg/kg/day) improved the lung/body weight ratio. Pulmonary arteries isolated from monocrotaline-treated rats exhibited an increase in basal tone in the resting state, indicating that they had intrinsic tone. Three weeks of treatment with olmesartan decreased this intrinsic tone. These data suggest that long-term treatment with olmesartan has beneficial effects on monocrotaline-induced pulmonary hypertension and subsequent right ventricular hypertrophy.     

Monocrotaline-induced cardiopulmonary injury in rats. Modification by the neutrophil elastase inhibitor SC39026

Rats were killed after 6 weeks of continuous ingestion of the pneumotoxic alkaloid monocrotaline (2.2 mg/kg/day), the neutrophil elastase inhibitor SC39026 (60 mg/kg/day), or both. Pulmonary reactions were evaluated by light and electron microscopy. Lung endothelial function was monitored by angiotensin converting enzyme (ACE) activity, plasminogen activator (PLA) activity, and prostacyclin (PGI2) and thromboxane (TXA2) production. Lung hydroxyproline content was measured as an index of interstitial fibrosis. Cardiac right ventricular hypertrophy was determined by the right ventricle to the left ventricle plus septum weight ratio (RV/LV + S). Rats receiving SC39026 alone did not differ significantly from untreated control animals with respect to any of the quantitative endpoints, although rarefaction of Type I pneumocytes was observed in the electron micrographs of these animals. Monocrotaline-treated rats, in contrast, developed a significant increase in RV/LV + S, and exhibited pulmonary edema, inflammation, fibrosis, and muscularization and occlusive mural thickening of the pulmonary small arteries and arterioles. These monocrotaline-induced structural changes were accompanied by decreased lung ACE and PLA activities, and increased PGI2 and TXA2 production, and by an increase in lung hydroxyproline content. Cotreatment with SC39026 ameliorated the monocrotaline-induced pulmonary vascular wall thickening and the cardiac right ventricular hypertrophy. These data suggest that inappropriate neutrophil elastase activity contributes to monocrotaline pulmonary vasculopathy and hypertension. On the other hand, cotreatment with SC39026 had no significant effect on the severity of the monocrotaline-induced lung inflammatory reaction, the pulmonary endothelial dysfunction, or the increase in lung hydroxyproline content.     

Captopril attenuates hypertension and renal injury induced by the vascular endothelial growth factor inhibitor sorafenib

相似文献