Fluorofenidone inhibits apoptosis of renal tubular epithelial cells in rats with renal interstitial fibrosis

This study aimed to investigate the mechanism of fluorofenidone (AKF-PD) in treating renal interstitial fibrosis in rats with unilateral urinary obstruction (UUO). Thirty-two male Sprague-Dawley rats were randomly divided into sham, UUO, UUO + enalapril, and UUO + AKF-PD groups. All rats, except sham, underwent left urethral obstruction surgery to establish the animal model. Rats were sacrificed 14 days after surgery, and serum was collected for renal function examination. Kidneys were collected to observe pathological changes. Immunohistochemistry was performed to assess collagen I (Col I) protein expression, and terminal deoxynucleotidyl transferase-mediated nick end-labeling staining to observe the apoptosis of renal tubular epithelial cells. The expression of Fas-associated death domain (FADD), apoptotic protease activating factor-1 (Apaf-1), and C/EBP homologous protein (CHOP) proteins was evaluated by immunohistochemistry and western blot analysis. AKF-PD showed no significant effect on renal function in UUO rats. The pathological changes were alleviated significantly after enalapril or AKF-PD treatment, but with no significant differences between the two groups. Col I protein was overexpressed in the UUO group, which was inhibited by both enalapril and AKF-PD. The number of apoptotic renal tubular epithelial cells was much higher in the UUO group, and AKF-PD significantly inhibited epithelial cells apoptosis. The expression of FADD, Apaf-1, and CHOP proteins was significantly upregulated in the UUO group and downregulated by enalapril and AKF-PD. In conclusion, AKF-PD improved renal interstitial fibrosis by inhibiting apoptosis of renal tubular epithelial cells in rats with UUO.

Inhibición de la Enzima Convertidora de Angiotensina I con hidrolizados proteicos de Jatropha curcas / Angiotensin I-Converting Enzyme inhibition with protein hydrolysates from Jatropha curcas / Inibição da Enzima Conversora de Angiotensina I com hidrolisados proteicos de Jatropha curcas

Se evaluó la actividad inhibitoria in vitro de los hidrolizados proteínicos obtenidos a partir de la harina desgrasada y del aislado proteínico provenientes del grano de Jatropha curcas L. sobre la actividad de la enzima convertidora de angiotensina I (ECA-1), con la finalidad de emplearlos en un futuro para la formulación de alimentos funcionales. Los hidrolizados fueron obtenidos empleando alcalasa y el sistema enzimático pepsina-pancreatina. Se calculó la concentración media inhibitoria (IC50) para medir el grado de inhibición de la actividad enzimática de ECA-1. Fueron seleccionados los hidrolizados con el menor tiempo de hidrólisis (60 min) para evaluar la bioactividad, dado que las cinéticas de hidrólisis enzimática de la harina desgrasada y del aislado proteínico no encontraron diferencias significativas en el grado de hidrólisis para los tiempos de reacción en cada sistema (60, 90 y 120 min). Los valores de IC50 que presentaron el mejor efecto de inhibición sobre la ECA-I fueron 2,8 y 7,0 µg/mL, obtenidos a partir del aislado proteínico con la enzima alcalasa y con el sistema secuencial pepsina-pancreatina, respectivamente. Los hidrolizados de J. curcas podrían ser incorporados en la elaboración de alimentos funcionales y ser aplicados en tratamientos para personas con hipertensión por su efecto inhibitorio sobre la ECA-I.

In vitro angiotensin I-converting enzyme (ACE) inhibitory activity was evaluated in protein hydrolysates from defatted meal and protein isolate from Jatropha curcas L. Seed, in order to determine their potential inclusion in functional food formulation. Hydrolysates were produced using Alcalase® or a sequential pepsin-pancreatin enzymatic system. Mean inhibitory concentration (IC50) was used to measure the degree of ACE enzymatic activity inhibition. Bioactivity was evaluated in the hydrolysates with the lowest hydrolysis time (60 min) given that no differences in degree of hydrolysis in terms of reaction time in each system were observed (60, 90 and 120 min) in the enzymatic hydrolysis kinetics for the defatted meal and protein isolate. The protein isolate exhibited the highest inhibitory effect, as seen in the IC50 values: 2.8 µg/mL in the alcalase system and 7.0 µg/mL in the pepsin-pancreatin system. Hydrolysates from J. curcas seed exhibit ACE inhibition and could be incorporated into functional foods or treatments for those suffering hypertension.

Foi avaliada a atividade inibitória in vitro dos hidrolisados proteicos obtidos a partir da farinha desengordurada e do isolado proteico provenientes do grão de Jatropha curcas L. sobre a atividade da enzima conversora de angiotensina I (ECA-1), com o objetivo de utilizá-los num futuro para a formulação de alimentos funcionais. Os hidrolisados foram obtidos usando alcalase e o sistema enzimático pepsina-pancreatina. Foi calculada a concentração média inibitória (IC50) para medir o grau de inibição da atividade enzimática da ECA-1. Foram selecionados os hidrolisados com o menor tempo de hidrólise (60 min.) para avaliar a bioatividade visto que as cinéticas de hidrólise enzimática da farinha desengordurada e do isolado proteico não encontraram diferenças significativas no grau de hidrólise para os tempos de reação para cada sistema (60, 90 e 120 min.). Os valores de IC50 que apresentaram o melhor efeito de inibição sobre a ECA-I foram 2.8 e 7.0 µg/mL obtidos a partir do isolado proteico com a enzima alcalase e com o sistema sequencial pepsina-pancreatina respectivamente. Os hidrolisados de J. curcas poderiam ser incorporados na elaboração de alimentos funcionais e ser aplicados em tratamentos para pessoas com hipertensão por seu efeito inibitório sobre a ECA-I.

Angiotensin-converting enzyme inhibition by lisinopril enhances liver regeneration in rats

Bradykinin has been reported to act as a growth factor for fibroblasts, mesangial cells and keratinocytes. Recently, we reported that bradykinin augments liver regeneration after partial hepatectomy in rats. Angiotensin-converting enzyme (ACE) is also a powerful bradykinin-degrading enzyme. We have investigated the effect of ACE inhibition by lisinopril on liver regeneration after partial hepatectomy. Adult male Wistar rats underwent 70 percent partial hepatectomy (PH). The animals received lisinopril at a dose of 1 mg kg body weight-1 day-1, or saline solution, intraperitoneally, for 5 days before hepatectomy, and daily after surgery. Four to six animals from the lisinopril and saline groups were sacrificed at 12, 24, 36, 48, 72, and 120 h after PH. Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen using the PC-10 monoclonal antibody. The value for the lisinopril-treated group was three-fold above the corresponding control at 12 h after PH (P<0.001), remaining elevated at approximately two-fold above control values at 24, 36, 48 (P<0.001), and at 72 h (P<0.01) after PH, but values did not reach statistical difference at 120 h after PH. Plasma ACE activity measured by radioenzymatic assay was significantly higher in the saline group than in the lisinopril-treated group (P<0.001), with 81 percent ACE inhibition. The present study shows that plasma ACE inhibition enhances liver regeneration after PH in rats. Since it was reported that bradykinin also augments liver regeneration after PH, this may explain the liver growth stimulating effect of ACE inhibitors

Differential effects of isoproterenol on the activity of angiotensin-converting enzyme in the rat heart and aorta

The excessive stimulation of beta-adrenergic receptors in the heart induces myocardial hypertrophy. There are several experimental data suggesting that this hypertrophy may also depend, at least partially, on the increase of local production of angiotensin II secondary to the activation of the cardiac renin-angiotensin system. In this study we investigated the effects of isoproterenol on the activity of angiotensin-converting enzyme (ACE) in the heart and also in the aorta and plasma. Male Wistar rats weighing 250 to 305 g were treated with a dose of (ñ)-isoproterenol (0.3 mg kg-1 day-1, N = 8) sufficient to produce cardiac hypertrophy without deleterious effects on the pumping capacity of the heart. Control rats (N = 7) were treated with vehicle (corn oil). The animals were killed one week later. ACE activity was determined in vitro in the four cardiac chambers, aorta and plasma by a fluorimetric assay. A significant hypertrophy was observed in both ventricular chambers. ACE activity in the atria remained constant after isoproterenol treatment. There was a significant increase (P<0.05) of ACE activity in the right ventricle (6.9 = 0.9 to 8.2 = 0.6 nmol His-Leu g-1 min-1) and in the left ventricle (6.4 ñ 1.1 to 8.9 ñ 0.8 nmol His-Leu g-1 min-1). In the aorta, however, ACE activity decreased (P<0.01) after isoproterenol (41 = 3 to 27 = 2 nmol His-Leu g-1 min-1) while it remained unchanged in the plasma. These data suggest that ACE expression in the heart can be increased by stimulation of beta-adrenoceptors. However, this effect is not observed on other local renin-angiotensin systems, such as the aorta. Our data also suggest that the increased sympathetic discharge and the elevated plasma concentration of catecholamines may contribute to the upregulation of ACE expression in the heart after myocardial infarction and heart failure

Effect of chloride and diamide on angiotensin converting enzyme from sheep testis and epididymis.

Effect of chloride and diamide on testicular and epididymal angiotensin converting enzyme (ACE) activity was investigated using Hip-His-Leu as substrate in sheep. The chloride ions functioned as ACE activators, however, there was no linear correlation between the two. The optimum chloride concentrations were 500 mM for epididymal ACE and 900-1100 mM for testicular ACE. Further, optimum chloride concentration increased ACE activity of testis and epididymis 25.40- folds and 12.84- folds respectively of the activities at physiological chloride concentration. The differences found in the effect of chloride on testicular and epididymal ACE activity suggest dissimilar three dimensional structure of ACE in these tissues. Increased testicular and epididymal ACE activity on diamide pretreatment indicates that tissue oxidation may affect ACE activity.

Inhibition of angiotensin converting enzyme from sheep tissues by captopril, lisinopril and enalapril.

Inhibition of angiotensin converting enzyme(EC 3.4,15.1, ACE) in presence of captopril, lisinopril and enalapril were investigated in kidney, lung and serum of sheep using Hip-His-Leu(HHL) as substrate. The activity in kidney, lung and serum was inhibited at HHL concentration above 5 mM. The inhibitory constants (IC50) ranged between 5.6 nM for serum ACE with lisinopril and 70000 nM for renal ACE with enalapril while Ki ranged from 1.0 nM for serum ACE with lisinopril to 12000 nM for kidney ACE with enalapril. Differences in inhibition observed in different tissues suggest that the inhibitors may block function(s) of ACE to varying degrees in each tissue.

Ativaçäo da enzima conversora de angiotensina no coraçäo após infarto do miocárdio e suas repercussöes no remodelamento ventricular / Activation of the cardiac angiotensin-converting enzime after infaction im rats and its role ventricular remodeling

OBJETIVO: Determinar as alteraçöes de atividade da enzima conversora de angiotensina (ECA) no coraçäo com infarto do miocárdio (IM) e comparar os efeitos do captopril e losartan em parâmetros morfológicos e funcionais de ratos com IM. MÉTODOS: O IM foi produzido em ratos Wistar por ligadura de ramos da artéria coronária esquerda. Os controles (Con) foram submetidos a uma cirurgia fictícia. Animais com IM e Con foram tratados com captopril (30 mg/kg/dia) ou losartan (15 ma/kg/dia) e estudados 30 dias após, determinando-se a atividade da ECA nos ventrículos direito (VD) e esquerdo (VE), as alteraçöes hemodinâmicas e as concentraçöes de hidroxiprolina (OH-Pro) e proteína total no VD e VE. RESULTADOS: A atividade da ECA aumentou no VD (+25 "por cento") e VE (+70 "por cento") após IM. A maior atividade foi observada na cicatriz fibrótica, onde atingiu cerca de 4,5 vezes a do músculo do VE que sobreviveu ao IM ("fórmula). O IM derterminou aumento da pressäo diastólica final igualmente eficazes em atenuar a hipertrofia e o aumento da pré-carga. O captopril também atenuou o aumento de OH-Pro no VD e VE após IM. O IM reduziu a concentraçäo de proteína principalmente no músculo de VE, efeito esse acentuado pelo captopril. CONCLUSÄO: A grande atividade da ECA na cicatriz deve produzir altas concentraçöes de angiotensina II (AII) no sangue que drena da cicatriz. Os efeitos dos inibidores da ECA seriam decorrentes , principalmente, da reduçäo de geraçäo local de AII, e näo de aumento de cininas, uma vez que captopril e losartan exerceram efeitos similares no remodelamento pós-infarto.

Vascular-derived kinins and local control of vascular tone

The vascular itself, through a complex interplay of endocrine, neurocrine and autoparacrine mechanisms, plays an active role in vascular homeostasis. The endothelial cell senses humoral and hemodynamic changes and respondes by secreting a variety of metabolically active substances that act locally causing either vasodilatation or vasoconstriction. Kallikrein (KK) and the nRNA for KK are present in arteries and veins. Vascular KK releases Kinins from kininogen which circulate in plasma and is also present in vascular tissue. Vascular-derived kinins induce vasodilatation through the release of endothelial compounds ( prostacyclin, EDRFs and cytochrome P-450). Disturbance in the delicate balance between vasodilators and vasoconstrictiors may play a role in the development of hypertension. Vascular kallikrein (VKK) was significantly (P < 0.05) elevated after 2 weeks of development of renovascular and mineralocorticoid hypertension, and blood pressure was only slightly elevated. However, VKK decreased in both experimental models when blood pressure was incresed. It is possible that the increase in VKK in the early stages resulted in incresead local vasodilatory activity, thus counteracting the rise in blood pressure. As hypertension developed, KK was significantly decreased in arteries. The decrease in arterial KK during established hypertension is most likely secondary to high blood pressure....