For an appropriate extrapolation to patients with peripheral arterial obstructive disease, we tested the efficacy of monocyte chemoattractant protein 1 (MCP-1) treatment in a porcine hindlimb ligation model. In 40 minipigs, a femoral artery ligation was performed. Control animals were examined immediately after ligation (n = 4) or after 2 wk of intra-arterial infusion of PBS (n = 11). A second group of animals was evaluated after intra-arterial infusion of 2.0 microg/h of MCP-1 for 48 h (followed by 12 days of PBS; n = 13) or 2 wk continuously (n = 12). In the terminal experiment after 2 wk, resting flow to the leg and peripheral arterial pressures were assessed without vasodilatation. Subsequently, vascular conductance was determined by using a pump-driven extracorporal circulation during maximal vasodilatation. The results showed that resting blood flow to the hindlimb was 53% of the normal after 2 wk of infusion of PBS, compared with 81% in both MCP-1 treatment groups (P < 0.05). Collateral conductance was 645 +/- 346 ml x min(-1) x mmHg(-1) after 2 wk of infusion with PBS, compared with 1,070 +/- 530 and 1,158 +/- 535 ml x min(-1) x mmHg(-1) after 48 h and 2 wk treatment with MCP-1, respectively (P < 0.05). Modulation of the process of arteriogenesis is feasible in this large animal model via intra-arterial infusion of the Cys-Cys-chemokine MCP-1.

Abstract-Cardiac hypertrophy is often associated with an increased sympathetic drive, and both in vitro and in vivo studies have demonstrated the development of cardiomyocyte hypertrophy in response to either ␣-or ␤-adrenergic stimulation. Because an association between the Na ϩ /H ϩ exchanger and cellular growth has been proposed, this study aimed to analyze the possible role of the antiporter in isoproterenol-induced cardiac hypertrophy. Isoproterenol alone (5 mg/kg IP once daily) or combined with a selective inhibitor of the Na ϩ /H ϩ exchanger activity (3 mg · kg) was given to male Wistar rats for 30 days. Sex-and age-matched rats that received 0.9% saline IP daily served as controls. Echocardiographic follow-up showed a 33% increase in left ventricular mass in the isoproterenol-treated group, whereas it did not increase in the isoproterenolϩBIIB723-treated group. Heart weight-to-body weight ratio at necropsy was 2.44Ϯ0.11 in controls and increased to 3.35Ϯ0.10 (PϽ0.05) with isoproterenol, an effect that was markedly attenuated by BIIB723 (2.82Ϯ0.07). Intense cardiomyocyte enlargement and severe subendocardial fibrosis were found in isoproterenol-treated rats, and both effects were attenuated by BIIB723. Myocardial Na ϩ /H ϩ exchanger activity and protein expression significantly increased in isoproterenol-treated rats compared with the control group (1.45Ϯ0.11 vs 0.91Ϯ0.05 arbitrary units, PϽ0.05). This effect was significantly reduced by BIIB723 (1.17Ϯ0.02, PϽ0.05). In conclusion, our results show that Na ϩ /H ϩ exchanger inhibition prevented the development of isoproterenolinduced hypertrophy and fibrosis, providing strong evidence in favor of a key role played by the antiporter in this model of cardiac hypertrophy. Key Words: hypertrophy, cardiac Ⅲ signal transduction Ⅲ antiporters Ⅲ fibrosis Ⅲ adrenergic receptor agonists I ncreased sympathetic activity is often implicated in the development of cardiac hypertrophy (CH). A correlation between cardiac mass and sympathetic activity was found in young hypertensive humans, 1 and long-term infusion of subpressor doses of norepinephrine leads to CH in dogs and rats. 2,3 This cardiotrophic effect of catecholamines involves both ␣-or ␤-adrenergic receptors. 4 It is well recognized that repeated or continuous injections of the ␤-adrenoceptor agonist isoproterenol (Iso) causes, within days, clear CH, 5 and therefore it represents a useful experimental model.Although several mechanisms have been imputed to underlie the cardiotrophic action of Iso, 5-7 the exact nature is still under debate. Because cumulative evidence supports a cause-effect link between the activity of the Na ϩ /H ϩ exchanger (NHE) and cardiac cell growth (Cingolani and Camilión de Hurtado 8 ), we sought to analyze the possible role of NHE activity in Iso-induced CH by taking advantage of the specific, orally active inhibitor against NHE isoform 1 (NHE-1). This study provides evidence indicating a key role for NHE-1 activity as a mechanism underlying the development of CH and fibrosis induced by I...

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The purpose of the present study was to investigate the renoprotective effect of telmisartan, an angiotensin II receptor antagonist, on the early stages of diabetic nephropathy in obese Zucker rats, which is a type 2-related diabetes mellitus model. Telmisartan 1, 3 or 10 mg/kg/day was orally administered to 7-week-old rats that demonstrated glucose tolerance without albuminuria or proteinuria, for 24 consecutive weeks (Experiment A). In another experiment (Experiment B), oral administration of telmisartan 10 mg/kg/day was initiated at the age of 16 weeks after the rats demonstrated marked proteinuria, and continued for 24 weeks. Telmisartan inhibited the increase in proteinuria and albuminuria in a dose-dependent manner, and the inhibition for all telmisartan groups was statistically significant by the completion of administration (Experiment A). Telmisartan also displayed similar inhibitory effects on proteinuria and albuminuria in Experiment B. Histologically, telmisartan [3 and 10 mg/kg/day] was associated with a significant decrease in the progression of glomerulosclerosis, and significantly improved interstitial cell infiltration, interstitial fibrosis and dilation and atrophy of renal tubules. Furthermore, telmisartan treatment was associated with a tendency towards normalized plasma lipids (total cholesterol and triglyceride). Our results suggest that telmisartan has a definite renoprotective effect against renal injury in type II diabetic nephropathy.

The purpose of this study was to investigate the renoprotective effect of telmisartan on the advanced stages of nephropathy in rats with 5/6 nephrectomy (5/6 Nx).Telmisartan was orally administered for 12 weeks to rats that previously underwent 5/6 Nx or sham operations. After completion of the administration period, the degree of renal injury was examined histopathologically using indices of glomerulosclerosis and lesions of the renal tubule and interstitium.An immunohistochemical staining for transforming growth factor—beta (TGF-β1) was also performed. The suppression of urinary protein was statistically significant in surviving animals dosed with telmisartan.The enalapril group's urinary protein was also significantly suppressed for these same parameters in surviving animals. Histopathologically, telmisartan significantly decreased the progression of glomerulosclerosis and the interstitial cell infiltration at all doses tested. As assessed by immunohistochemical staining the TGF-β1 reactivity in the glomerular tissue tended to decrease in the telmisartan group when compared to the vehicle group. Thus, the progressive Thus, telmisartan ameliorates the progressive nephropathy in the remaining kidney after 5/6 Nx by non-haemodynamic as well as antihypertensive actions of the drug. pharmacological properties of telmisartan, clinical studies have been conducted to evaluate the clinical effectiveness and safety of telmisartan on diabetic nephropathy in patients with type 2 diabetes. It has been reported that telmisartan arrested progressive renal dysfunction in hypertensive patients with early-stage diabetic nephropathy. Makino et al.8 reported the effectiveness of this drug therapy in suppressing the progression of nephropathy in type 2 diabetic patients with or without hypertension, without serious safety concerns. Remuzzi and Remuzzi9 reviewed the potential protective effects of telmisartan on renal function deterioration and suggested that telmisartan may effectively ameliorate renal dysfunction in patients affected by the metabolic syndrome. In addition, telmisartan also showed renoprotective effects in some animal models: spontaneously hypertensive rats (SHR), 10 as well as the hypertensive diabetic model that combines SHR with streptozotocininduced diabetes.11 Ohmura et al.12 investigated the mechanism of the renoprotective effect of telmisartan using obese Zucker diabetic rats. Ciclosporin A-induced nephropathy in pigs was attenuated by telmisartan without any reduction of blood pressure (BP).13 This animal data suggested that the suppressive effect on the progression of nephropathy might be due to both haemodynamic and non-haemodynamic action(s) of the drug.

Severe blood loss is a major cause of death occurring within hours of traumatic injury. Na+/H+ exchange (NHE-1) activity is an important determinant of the extent of ischemic myocardial injury. The goal of the present study was to test the hypothesis that NHE-1 inhibition delays the onset of hypovolemic circulatory shock, thereby preventing early death due to severe hemorrhage in pigs. Severe hypovolemia was studied in 16 (25.2 kg) anesthetized male pigs in steps of 10-, 20-, 30-, 40-, and 50-mL kg(-1) blood loss, each in 30-min intervals. Shed blood resuscitation was started 30 min after 50 mL kg(-1) blood loss. The experiment was terminated after 3 h of resuscitation. Eight pigs were used as seline control. Eight pigs received 3 mg kg(-1) benzamide, N-(aminoiminomethyl)-4-[4-(2-furanylcarbonyl)-1-piperazinyl]-3-(methylsulfonyl), methanesulfonate (NHE-1 inhibitor) 15 min before hemorrhage. Seven control pigs died at 40- to 50-mL kg(-1) blood loss. One control pig survived initial resuscitation but died soon after. In contrast, all animals treated with NHE-1 inhibitor survived the entire protocol. In control animals, cardiac output and MAP gradually decreased at each step of blood loss with marked increase in heart rate. Cardiovascular decompensation occurred at 40 mL kg(-1) blood loss. Na+/H+ exchange inhibition increased oxygen delivery, attenuated cardiovascular decompensation, delayed the onset of irreversible hypovolemic circulatory shock, and enabled resuscitation to survival. Echocardiography analysis showed that myocardial hypercontracture gradually developed with each step of blood loss in control animals, but this hypercontracture was attenuated in the animals receiving the NHE-1 inhibitor. We conclude that NHE-1 inhibition attenuates ischemic myocardial hypercontracture, cardiovascular decompensation, delays the onset of hypovolemic circulatory shock, and prevents early death in severe hemorrhage.

Local infusion of recombinant monocyte chemoattractant protein-1 (MCP-1) has been shown to enhance collateral artery formation in rabbit and pig hindlimb models. Owing to clinical disadvantages of protein infusion, a nonviral, liposome-based MCP-1 gene transfer was developed. Collateralization in a porcine hindlimb model served to provide a proof-of-principle for the functional benefit of MCP-1 overexpression. Development of arterial conductance as a measure of functionally relevant collateralization was evaluated in occluded as well as untreated hindlimbs in each animal. At the time of occlusion, MCP-1 and control DNA/DC-30 lipoplexes were transferred to femoral arteries of Goettingen minipigs (two therapeutic MCP-1 groups: 2 and 4 mg and one control group), using the Infiltrator s local drug-delivery device. At 2 weeks following occlusion, collateralization was determined as changes in peripheral haemodynamic conductance, peripheral over aortic blood pressure ratio and angiographically visible morphology of the peripheral vessel tree. Nonviral MCP-1 gene transfer significantly improved peripheral conductance (control 11.6972.78%, 2 mg 23.8172.81%, Po0.05 and 4 mg 23.3673.1%, Po0.05; n ¼ 12 per group) as well as the ratio of peripheral over aortic blood pressure (control 0.6470.03%, 2 mg 0.7570.02%, Po0.05 and 4 mg 0.7570.02%, Po0.05; n ¼ 12 per group) when compared to the untreated controls 2 weeks after occlusion. Thus, it could be demonstrated for the first time that in situ overexpression of MCP-1 following local nonviral gene transfer is a potential approach to improve peripheral collateralization.

Na+/H+ exchange (NHE) plays an important role in the regulation of the intracellular pH (pHi) and in cardiac cell injury induced by ischemia and reperfusion. In the present study, we investigated the effects of BIIB513, a selective NHE-1 inhibitor on myocardial ischemia induced arrhythmias and myocardial infarction, provoked by 30 minutes of left main coronary artery occlusion followed by 2 hours of reperfusion in an anesthetized rat model. Intravenous administration of BIIB513 (0.01-3.0 mg/kg) did not induce changes in blood pressure or heart rate. BIIB513 (0.01, 0.1, 0.3, 1.0, 3.0 mg/kg) given prior to the coronary artery occlusion dose-dependently reduced ventricular premature beats, ventricular tachycardia, and a complete suppression of ventricular fibrillation down to the dose of 0.1 mg/kg. BIIB513 (0.01, 0.1, 0.3, 1.0, 3.0 mg/kg) given prior to the coronary artery occlusion dose-dependently reduced the infarct size with an ED50 value of 0.16 mg/kg. BIIB513 (1.0 mg/kg) given prior to reperfusion also reduced infarct size by 47.3 +/- 13.1%. The reduction in infarct size was accompanied by a decrease in circulating levels of creatine phosphokinase (CPK). In conclusion, the present study demonstrates the cardioprotective ability of NHE-1 inhibition during myocardial ischemia and reperfusion by reducing serious ventricular arrhythmias and myocardial infarct size in anesthetized rats.