Angiotensin-converting Enzyme Inhibitor Captopril Research Articles

ADAMTS-1 contributes to the antifibrotic effect of Captopril by accelerating the degradation of type I collagen in chronic viral myocarditis

Angiotensin-converting enzyme (ACE) inhibitors have been demonstrated to have antifibrotic activity in myocardial fibrosis. A distintegrin and metalloprotease with thrombospondin type 1 motifs (ADAMTS-1) is a newly discovered metalloproteinase. It was reported ADAMTS-1 had novel gelatin (type I collagen) degrading activities. We examined the role of ADAMTS-1 in the antifibrotic activity of the ACE inhibitor Captopril in a chronic viral myocarditis (CVMC) model. Balb/c mice were assigned to five groups: normal control group1 (group 1), normal control group2 (group 2), CVMC model group (group 3), CVMC control group (group 4) and Captopril therapy group (group 5). Group 3, 4 and 5 received Coxsackievirus B 3 to induce CVMC and group 5 was treated with Captopril (100 mg/kg)for 28 days. Heart sections were stained with picrosirius red and collagen volume fraction calculated. ADAMTS-1 expression was determined by Western blot. Type I collagen and carboxyterminal telopeptide of type I collagen (ICTP) were measured by RT-PCR. Group 4 mice had significantly increased collagen volume fraction compared to groups 2 and 5 ( P < 0.001, P < 0.001, respectively) and higher type I collagen mRNA expression than groups 2 and 5 ( P < 0.001, P < 0.001, respectively). Group 5 ADAMTS-1 and ICTP expression was significantly higher than in groups 2 and 4 ( P < 0.001, P < 0.001, respectively). ADAMTS-1 levels in group 5 negatively correlated with collagen volume fraction ( r = − 0.68, P < 0.01) and type I collagen ( r = − 0.67, P < 0.01) but positively correlated with ICTP ( r = 0.72, P < 0.01). We conclude that ADAMTS-1 contributes to the antifibrotic effect of Captopril by accelerating the degradation of type I collagen in CVMC.

Effects of a protocol of ischemic postconditioning and/or captopril in hearts of normotensive and hypertensive rats

Brief periods (a few seconds) of cyclic coronary occlusions applied early in reperfusion induce a cardioprotection against infarct size, called postconditioning (PostC) in which B(2)-bradykinin receptors play a pivotal role. Since angiotensin-converting enzyme (ACE) inhibitors reduce degradation of kinins, we studied the effects of PostC on infarct size and postischemic myocardial dysfunction in both normotensive (WKY) and spontaneously hypertensive rats (SHR) acutely or chronically treated with the ACE inhibitor Captopril. Isolated hearts from SHR and WKY rats were subjected to the following protocols: (a) ischemia for 30- and 120-min reperfusion (I/R); (b) I/R + PostC protocol (5-cycles 10-s I/R); (c) pretreatment with Captopril for 4-weeks before to subject the hearts to I/R with or without PostC maneuvers. Some SHR hearts were treated with Captopril during the 20- or 40-min early reperfusion with or without PostC maneuvers. Cardiac function was assessed in vivo with echocardiography. Left ventricular pressure and infarct size were measured ex vivo. Chronic Captopril significantly reduced left ventricular hypertrophy in SHR, and reduced infarct size in both WKY and SHR hearts. PostC maneuvers significantly reduced infarct size in WKY, but not in SHR hearts. Yet, PostC slightly improved postischemic systolic function in untreated SHR. Captopril given in reperfusion was unable to limit I/R injury in SHR hearts. Data show that PostC protection against infarct size is blunted in SHR and that PostC is unable to add its protective effect to those of chronic Captopril, which per se reduces cardiac hypertrophy and heart susceptibility to I/R insult.

Effect of angiotensin-converting enzyme inhibitor on matrix metalloproteinase-9 activity in patients with Kawasaki disease

Background Matrix metalloproteinase (MMP)-9 is thought to be involved in coronary artery aneurysms (CAAs) in patients with Kawasaki disease (KD); however, MMP-9 inhibitors are not used clinically. This study investigated whether the angiotensin-converting enzyme (ACE) inhibitor captopril could inhibit serum MMP-9 activity using serum from KD patients in an in vitro experiment. Methods In 7 KD patients, serum MMP-9 activity was measured using the MMP-9 assay kit 3 times: before and after intravenous immunoglobulin (IVIG) treatment, and during the convalescent phase. The effect of captopril on MMP-9 activity was also assessed using serum obtained before IVIG treatment. Results Serum MMP-9 activity was significantly higher during the pre-treatment phase than during the post-treatment and convalescent phases. MMP-9 activity during the pre-treatment phase was dose-dependently inhibited by captopril, and the IC 50 for MMP-9 was 500 nM. The potency of captopril for MMP-9 inhibition was comparable to that for ACE inhibition. Conclusion ACE inhibitor may be effective for preventing CAA formation in KD patients, especially IVIG non-responders.

Lateral parabrachial nucleus and central amygdala in the control of sodium intake

The lateral parabrachial nucleus (LPBN) and the central nucleus of the amygdala (CeA) are important areas for the control of sodium appetite. In the present study we investigated the effects of bilateral lesions of the CeA on the facilitation of water and 0.3 M NaCl intake produced by the blockade of serotonergic mechanisms or activation of α 2-adrenoceptors with bilateral injections of methysergide or moxonidine, respectively, into the LPBN. Male Holtzman rats ( n=5–8) with bilateral sham or electrolytic lesions of the CeA (2 mA; 10 s) and stainless steel cannulas implanted bilaterally in the LPBN were used. In sham rats treated with the diuretic furosemide (10 mg/kg b.w.) combined with the angiotensin converting enzyme inhibitor captopril (5 mg/kg b.w) subcutaneously, bilateral injections of moxonidine (0.5 nmol) or methysergide (4 μg) into the LPBN increased 0.3 M NaCl intake (29.8±5.1 and 19.5±3.7 ml/2 h, respectively, versus vehicle: 8.3±1.4 ml/2 h) and water intake (17.9±3.7 and 23.3±2.8 ml/2 h, respectively, versus vehicle: 11.5±1.6 ml/2 h). Lesions of the CeA (5–18 days) abolished the increase in 0.3 M NaCl and water intake produced by bilateral injections of moxonidine (10.3±2.8 and 6.8±2.3 ml/2 h, respectively) and reduced the increase produced by methysergide (13.6±2.5 and 14.5±3.2 ml/2 h, respectively) into the LPBN. The present results show that the increase in water and 0.3 M NaCl intake produced by serotonergic blockade and α 2-adrenergic activation in the LPBN depends on the integrity of the CeA, suggesting that facilitatory mechanisms present in the CeA are essential for the increase of water and hypertonic NaCl intake produced by the blockade of the inhibitory mechanisms of the LPBN.

Angiotensin II stimulates trafficking of NHE3, NaPi2, and associated proteins into the proximal tubule microvilli

Angiotensin II (ANG II) stimulates proximal tubule (PT) sodium and water reabsorption. We showed that treating rats acutely with the angiotensin-converting enzyme inhibitor captopril decreases PT salt and water reabsorption and provokes rapid redistribution of the Na(+)/H(+) exchanger isoform 3 (NHE3), Na(+)/Pi cotransporter 2 (NaPi2), and associated proteins out of the microvilli. The aim of the present study was to determine whether acute ANG II infusion increases the abundance of PT NHE3, NaPi2, and associated proteins in the microvilli available for reabsorbing NaCl. Male Sprague-Dawley rats were infused with a dose of captopril (12 microg/min for 20 min) that increased PT flow rate approximately 20% with no change in blood pressure (BP) or glomerular filtration rate (GFR). When ANG II (20 ng x kg(-1) x min(-1) for 20 min) was added to the captopril infusate, PT volume flow rate returned to baseline without changing BP or GFR. After captopril, NHE3 was localized to the base of the microvilli and NaPi2 to subapical cytoplasmic vesicles; after 20 min ANG II, both NHE3 and NaPi2 redistributed into the microvilli, assayed by confocal microscopy and density gradient fractionation. Additional PT proteins that redistributed into low-density microvilli-enriched membranes in response to ANG II included myosin VI, DPPIV, NHERF-1, ezrin, megalin, vacuolar H(+)-ATPase, aminopeptidase N, and clathrin. In summary, in response to 20 min ANG II in the absence of a change in BP or GFR, multiple proteins traffic into the PT brush-border microvilli where they likely contribute to the rapid increase in PT salt and water reabsorption.

Calcium-sensing receptors modulate renin release in vivo and in vitro in the rat

Calcium-sensing receptors (CaSRs) have been localized in the juxtaglomerular apparatus where they may contribute to the regulation of renin release. In the present study, we investigated the in-vitro and in-vivo effects of the calcimimetic R-568 on renin release. In vitro, the effect of calcimimetics on renin release was assessed by incubating freshly isolated rat juxtaglomerular cells with or without R-568 (1 and 10 mumol/l) in serum-free medium in the presence or absence of forskolin or CaCl2. In vivo, we measured the impact of R-568 (20 ng/min intravenously) on the acute changes in plasma renin activity (PRA) induced by either a 90 min infusion of the angiotensin-converting enzyme inhibitor captopril, or the beta-receptor agonist isoproterenol, or of a vehicle in or after a furosemide challenge in conscious Wistar rats. In vitro, R-568 dose-dependently blunted renin release, but also reduced the increase in renin due to forskolin (P < 0.01). Both isoproterenol and enalapril increased in vivo PRA to 3.1 +/- 0.3 and 3.7 +/- 0.5 ng Ang I/ml per h, respectively (P < 0.01), compared with vehicle (1.5 +/- 0.2 ng Ang I/ml per h). R-568 significantly reduced PRA to 2.1 +/- 0.1 ng/ml per h in isoproterenol-treated rats and to 1.6 +/- 0.2 ng/ml per h in enalapril-treated rats (P < 0.05). In low-salt treated animals, acute infusion of furosemide increased PRA from 8.7 +/- 3.2 to 18.6 +/- 2.3, whereas R-568 partially blunted this rise to 11.2 +/- 1.5 (P = 0.02). In vivo, R-568 significantly lowered serum calcium and PTH1-84, but the drug-induced changes in PRA were independent of the changes in calcium and parathyroid hormone. After the recent discovery of CaSRs in juxtaglomerular cells of mice, our results confirm the presence of such receptors in rats and demonstrate that these receptors modulate renin release both in vitro and in vivo. This suggests that CaSRs play a role as a regulatory pathway of renin release.

The effects of ACE inhibitors and other antihypertensive drugs on cardiovascular risk factors and atherogenesis

The effects of antihypertensive therapy on the atherosclerotic process and differences among various treatment approaches have been studied in several animal models. Studies in cholesterol-fed rabbits have indicated that beta blockers and calcium antagonists can inhibit the development of aortic atherosclerosis induced by marked hypercholesterolemia. However, no such antiatherosclerotic action has been apparent with these agents in the Watanabe heritable hyperlipidemic (WHHL) rabbit. A study was conducted to determine the effects of the angiotensin-converting enzyme (ACE) inhibitor captopril administered orally for 9 months on the development of atherosclerosis in normotensive WHHL. Compared with controls, the treated animals had a significant reduction in atherosclerosis of the descending thoracic aorta. These effects were associated with significantly lower blood pressure, though within the normal range, in captopril-treated versus control animals. In the captopril group, the atherosclerotic plaques were thinner and less cellular than plaques of similar gross severity in control WHHL. The findings indicate that the ACE inhibitor captopril can inhibit atherogenesis in the WHHL, which has been resistant to such therapy with other antihypertensive drugs.

The role of ACE inhibitors in the treatment of arrhythmias

Several experimental models have been studied to determine the role of angiotensin-converting enzyme (ACE) inhibitors in reducing ischemic and reperfusion arrhythmias. Studies of left main coronary artery occlusion in isolated perfused rat hearts have shown that the ACE inhibitor captopril reduced reperfusion ventricular fibrillation from 100% to 0% and was associated with a reduction in purine overflow and in norepinephrine release. These effects were abolished in the presence of indomethacin. In an anesthetized rat model of acute myocardial infarction (MI), ACE inhibition reduced mean duration of ventricular fibrillation from 1,133 to 135. ACE inhibition at programmed electrical stimulation of the heart in a closed-chest pig model of acute MI reduced the inducibility of sustained, reproducible ventricular tachycardia from a mean of 42 to 8%. In this model, ventricular tachycardia could not be provoked in animals treated with captopril from the time of acute ischemia. Studies on the rate of ventricular ectopy in patients with poor left ventricular function have demonstrated a significant reduction with ACE inhibition. However, while a protective effect has been shown, the mechanism of action is still speculative.

The ACE inhibitors enalapril and captopril modulate cytokine responses in Balb/c and C57Bl/6 normal mice and increase CD4 +CD103 +CD25 negative splenic T cell numbers

Increasing evidence implies beneficial effects of angiotensin-converting enzyme (ACE) inhibitors beyond those of their original indications to control hypertension. One of the most attractive non-hemodynamic properties of ACE inhibitors is their ability to regulate cytokine production. The mechanism(s) underlying the role of ACE inhibitors on cytokine synthesis are not well understood but they have traditionally been attributed to the inhibition of angiotensin (Ang) II formation. In fact, it has been extensively demonstrated that ACE inhibitors decrease Ang II-induced production of proinflammatory cytokines and chemokines. However, it is not well described if inhibition of endogenous Ang II generation by ACE inhibitors modulates systemic cytokine production in mice. To verify that, in this work, we investigated the effects of treatment with the ACE inhibitors enalapril and captopril on cytokine synthesis in C57Bl/6 and Balb/c mice. Our results show that enalapril up regulates IL-10 produced by splenocytes from Balb/c and C57Bl/6 mice and captopril increased it only in Balb/c mice. Furthermore, CD4 +CD103 + presented increased IL-10 production after enalapril treatment. Enalapril as well as captopril short-term treatment enhanced IL-2 synthesis in Balb/c mice. Besides, enhanced IL-2 and IL-10 levels correlates with increased CD4 +CD103 +CD25 negative T cells numbers in spleens from enalapril-treated mice.

Angiotensin II is Necessary for Skeletal Muscle Regeneration Following Cardiotoxin‐induced Injury

Angiotensin II (Ang II) is a pleiotropic peptide involved in vasoactivity as well as cellular growth and proliferation. We examined whether Ang II is also a mediator of muscle regeneration by administering an ACE inhibitor (captopril) following cardiotoxin (ctx)‐induced muscle injury in C57BL/6 mice. 10 days following ctx injection, captopril treated mice demonstrated a delayed response in the myogenic program evidenced by sustained expression of Pax7 and Myf5 transcripts while myogenin mRNA, a marker of differentiating myoblasts, was significantly inhibited. This delay was also evident at the myofibre level with captopril treated mice exhibiting a significant ~3.5 fold elevation in eMHC gene expression. Importantly, newly formed fibres in the captopril treated group demonstrated an impaired hypertrophic response as fibre cross‐sectional area (CSA) from day 10 to day 21 was increased by 81% in the control group and only 27% in the captopril group. This resulted in an overall difference of 25% in CSA between groups at day 21 post injury. These effects do not appear to be due to a deficiency in protein synthesis as myonuclear domain size was unchanged between groups. Rather, there appears to be a loss of satellite cell content as the captopril treated group demonstrated a ~29% decrease in Pax7+ cells by day 21 post injury. This research was supported by NSERC.

Angiotensin II Activates IκB Kinase Phosphorylation of RelA at Ser536 to Promote Myofibroblast Survival and Liver Fibrosis

The transcription factor nuclear factor-kappaB (NF)-kappaB promotes survival of hepatic myofibroblasts and fibrogenesis through poorly defined mechanisms. We investigated the activities of angiotensin II and I kappaB kinase (IKK) in regulation of NF-kappaB activity and the role of these proteins in liver fibrosis in rodents and humans. Phosphorylation of the NF-kappaB subunit RelA at serine 536 (P-Ser(536)-RelA) was detected by immunoblot and immunohistochemical analyses. P-Ser(536)-RelA function was assessed using vectors that expressed mutant forms of RelA, cell-permeable blocking peptides, and assays for RelA nuclear transport and apoptosis. Levels of P-Ser(536)-RelA were compared with degree of fibrosis in liver sections from chronically injured rats and patients with hepatitis C virus-mediated fibrosis who had been treated with the AT1 antagonist losartan. Constitutive P-Ser(536)-RelA is a feature of human hepatic myofibroblasts, both in vitro and in situ in diseased livers. Autocrine angiotensin II stimulated IKK-mediated phosphorylation of RelA at Ser(536), which was required for nuclear transport and transcriptional activity of NF-kappaB. Inhibition of angiotensin II, the angiotensin II receptor type 1 (AT1), or IKK blocked Ser(536) phosphorylation and stimulated myofibroblast apoptosis. Treatment of fibrotic rodent liver with the angiotensin converting enzyme (ACE) inhibitor captopril or the IKK inhibitor sulphasalazine resulted in loss of P-Ser(536)-RelA-positive myofibroblasts and fibrosis regression. In human liver samples, increased numbers of P-Ser(536)-RelA-positive cells were associated with fibrosis that regressed following exposure to losartan. An autocrine pathway that includes angiotensin II, IKK, and P-Ser(536)-RelA regulates myofibroblast survival and can be targeted to stimulate therapeutic regression of liver fibrosis.

Activities of Angiotensin-Converting Enzymes ACE1 and ACE2 and Inhibition by Bioactive Peptides in Porcine Ocular Tissues

An active local renin-angiotensin system (RAS) has recently been found in the human eye. The aim of the present study was to compare the activities of central RAS enzymes (ACE1 and 2) in porcine ocular tissues, morphologically and physiologically close to the human eye. In addition, the effects of three ACE-inhibitory tripeptides on these enzymes were evaluated. Enucleated fresh porcine eyes were used. Activities of ACE1 and ACE2 and their inhibition by bioactive tripeptides (Ile-Pro-Pro, Val-Pro-Pro, Leu-Pro-Pro) as well as by a standard ACE-inhibitor captopril were assayed in the vitreous body, the retina and the ciliary body using fluorometric detection methods. Activity of ACE1 as well as ACE2 was found in all tissues evaluated. ACE1 activity was markedly higher in the ciliary body (3.7 +/- 0.7 mU/mg protein) than in retina (0.2 +/- 0.02 mU/mg), whereas ACE2 activities in the ciliary body (0.2 +/- 0.02 mU/mg) and retina (0.2 +/- 0.01 mU/mg) were at the same level. In the vitreous body ACE1 activity (8.2 +/- 0.31 nmol/min/mL) was manifold compared to that of ACE2 (0.1 +/- 0.02 nmol/min/mL). The tripeptides inhibited ACE1 at one-thousandth of the concentration needed to inhibit ACE2. All peptides studied evinced about equal inhibitory activities. To our knowledge the present findings constitute the first evidence of ACE2 activity in the ciliary and vitreous bodies, in addition to previously described activity in the retina. The known favorable effects of ACE2 products vs. those of ACE1 suggest a counterbalancing interaction of these two enzyme homologues in physiological regulation of ocular circulation and pressure and possible protective role in certain ophthalmic disorders such as glaucoma and diabetic retinopathy.

Dihydrotestosterone stimulates aldosterone secretion by H295R human adrenocortical cells

Men exhibit a higher incidence of cardiovascular diseases than do women. The cardiovascular actions of sex steroids have been suggested as primary factors in mediating this sex difference. The mechanisms by which sex steroids, androgens and estrogens, mediate cardiovascular actions remain unclear. Excess aldosterone secretion has been associated with cardiovascular diseases. The hypothesis tested in this study was that at physiological concentrations, androgens stimulate and estradiol inhibits aldosterone secretion by human adrenal cells. In contrast to our hypothesis, physiological concentrations of sex steroids did not modify aldosterone secretion by H295R human adrenocortical cells. However, supraphysiological concentrations (300–1000 nM) of dihydrotestosterone (DHT) significantly stimulated basal and Angiotensin II-mediated aldosterone secretion. The stimulatory effect of DHT on aldosterone secretion was not blocked by the classical androgen receptor blocker flutamide. The stimulatory effect of DHT on aldosterone secretion was also independent of the intra-adrenal renin–angiotensin system since it was neither modified by treatment with the Angiotensin II receptor type 1 blocker losartan or the angiotensin converting enzyme inhibitor captopril. Inhibitors of the calmodulin/calmodulin-dependent protein kinase (CaMK) and protein kinase C intracellular signaling pathways abolished the DHT stimulatory effect on aldosterone secretion by H295R cells. In conclusion, physiological concentrations of sex steroids did not modify aldosterone secretion by human adrenal cells. However, supraphysiological concentrations of DHT-stimulated aldosterone secretion by human adrenal cells by the calmodulin/CaMK and protein kinase C intracellular signaling pathways but independently of the classical androgen receptor. Supraphysiological doses of androgen may promote cardiovascular diseases via stimulation of aldosterone secretion.

P02-170 Comparative effects of captopril, losartan and PD123319 on the memory processes in rats

Aims:Renin-angiotensin system in the central nervous system participates in the processing of sensory information, learning and memory processes. Inhibitors of renin-angiotensin system, particularly angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists are reported to have potential effects in various learning and memory processes. In the present study we assessed the effects of angiotensin converting enzyme inhibitor captopril and the angiotensin AT1 receptors antagonists, lostartan and PD123319, in learning and memory processes by means of Y-maze and passive avoidance tasks. The anxiety state was measured in elevated plus maze.Methods:Male Wistar rats were divided into three groups: 1. sham-operated; 2. Captopril; 3. Losartan; 4. PD123319. All drugs were stereotaxically icv injected, rather than captopril (i.p.). Learning and memory tests began 2 weeks after the operation, and the ability of the rats to acquire the operant task was studied by means of Y-maze task and passive avoidance task, respectively. The anxiety state was measured in elevated plus maze.Results:Captopril, losartan and PD123319 significantly impaired spatial memory in Y-maze task, suggesting significant effects on short-term memory. In passive avoidance task, all drugs, significantly decreased step-through-latency, suggesting significant effects on long-term memory. In elevated plus maze measuring anxiety, all drugs diminished anxiety state.Conclusions:These results suggest the involvement of the brain renin-angiotensin system in learning and memory formation.

FREQÜÊNCIA DE EFEITOS ADVERSOS CAUSADOS POR INIBIDORES DA ENZIMA CONVERSORA DA ANGIOTENSINA RELATADOS POR PACIENTES ATENDIDOS NA UNIDADE BÁSICA DE SAÚDE – LARANJAL – PR

Os inibidores da enzima conversora da angiotensina (ECA) têm alta eficácia no tratamento da pressão arterial elevada, bem como a ser utilizado em situações de insuficiência cardíaca. O mecanismo de ação desses medicamentos é fornecido pela inibição da formação de angiotensina II, um potente agente vasoconstritor, através do bloqueio da ECA. Os efeitos adversos mais comuns são: tosse, hipotensão ortostática na primeira dose, erupção cutânea, perda do paladar, proteinúria, leucopenia e hipersensibilidade com edema angioneurótico. O estudo realizado é a avaliação do efeito colateral dos inibidores da enzima conversora da angiotensina. Os resultados foram analisados através do programa Epi Info 3.3.2 de 9 de fevereiro de 2005. Entre os itens variáveis sócio-demográficas, o sexo feminino tem 71,7% da amostra, a média de idade de 53 anos e ensino fundamental incompleto 67,9% das pessoas entrevistadas. Em relação ao estado civil, 83,0% eram casados, quanto ao regime domiciliar 51,9% pertenciam à primeira geração (com um cônjuge), sendo 66,0% tem como renda mensal 1 (um) salário mínimo. Em relação as variáveis farmacoepidemiológicas alguns dos resultados encontrados foram, o medicamento de uso mais freqüente foi o inibidor da ECA (Captopril), prescrito para 67,9% dos hipertensos, com aparecimento de tosse em aproximadamente 3 a 20% dos pacientes. Com relação à adesão ao tratamento 86,8% respondem positivamente. Diante da realidade assinalada é necessário aumentar o grau de conhecimento da população sobre a importância do controle da hipertensão arterial, e a adesão à terapêutica cardiovascular. É necessário e urgente garantir acesso dos pacientes hipertensos a serviços básicos de saúde, e incentivar políticas e programas comunitários. O primeiro passo é a educação dos pacientes, seus familiares e a comunidade, onde uma equipe multiprofissional poderá fornecer aos pacientes e à comunidade motivação para vencer os desafios e adotar atitudes que tornem as ações efetivas e permanentes.

Battle against the renin-angiotensin system: help from an unexpected party

1,25 Dihydroxyvitamin D3 is a key player in calcium and phosphorus homeostasis and bone formation, and disturbances in this system cause deleterious clinical effects. Besides these actions, there is accumulating evidence for nonclassical actions of 1,25(OH)2D3 and its analogues such as immunomodulation and antiproliferation. Low levels of 1,25(OH)2D3 in the circulation are associated with a high incidence of autoimmune diseases like multiple sclerosis. According to the data from in vitro experiments and animal models, vitamin D might diminish the proinflammatory immune response by enhancing regulatory T cell functionality [1]. An inverse association of circulating 25-OH vitamin D levels with blood pressure has been demonstrated, and likewise, it has been shown that the treatment with the vitamin D analogue alphacalcidiol reduces blood pressure [2,3]. Also, 1,25(OH)2D3 reduces plasma renin activity, angiotensin II (Ang II) and myocardial hypertrophy [4–6]. A murine model of vitamin D receptor (VDR) deficiency displays elevated renin mRNA and protein levels [7]. In 1α-hydroxylase knockout-mice, similar findings were found and the corresponding phenotype was rescued by the ACE inhibitor captopril and the Ang II type 1 blocker (ARB) losartan but not by a high calcium and phosphorus diet suggesting that these effects are independent [8]. In this light, a recent study investigated the combined effect of the ARB losartan and the non-calcaemic vitamin D analogue paricalcitol (19-nor-1,25-dihydroxyvitamin D2) on the development and progression of diabetic nephropathy [9]. Diabetic nephropathy is the most common cause of end-stage renal disease with an even increasing incidence throughout the western world [10]. Blockers of the

L-Arginine Fails to Prevent Ventricular Remodeling and Heart Failure in the Spontaneously Hypertensive Rat

The effects of long-term oral administration of L-arginine, a substrate for nitric oxide (NO) production, on left ventricular (LV) remodeling, myocardial function and the prevention of heart failure (HF) was compared to the angiotensin-converting enzyme (ACE) inhibitor captopril in a rat model of hypertensive HF (aged spontaneously hypertensive rat (SHR)). SHRs and age-matched normotensive Wistar-Kyoto (WKY) rats were assigned to either no treatment, treatment with L-arginine (7.5 g/l in drinking water) or captopril (1 g/l in drinking water) beginning at 14 months of age, a time when SHRs exhibit stable compensated hypertrophy with no hemodynamic impairment; animals were studied at 23 months of age or at the time of HF. In untreated SHR, relative to WKY, there was significant LV hypertrophy, myocardial fibrosis, and isolated LV muscle performance and response to isoproterenol (ISO) were depressed; and, 7 of 10 SHRs developed HF. Captopril administration to six SHRs attenuated hypertrophy and prevented impaired inotropic responsiveness to ISO, contractile dysfunction, fibrosis, increased passive stiffness, and HF. In contrast, L-arginine administration to SHR increased LV hypertrophy and myocardial fibrosis while cardiac performance was depressed; and 7 of 9 SHRs developed HF. In WKY, L-arginine treatment but not captopril resulted in increased LV weight and the contractile response to ISO was blunted. Neither L-arginine nor captopril treatment of WKY changed fibrosis and HF did not occur. These data demonstrate that in contrast to captopril, long-term treatment with L-arginine exacerbates age-related cardiac hypertrophy, fibrosis, and did not prevent contractile dysfunction or the development of HF in aging SHR.

Induction of apoptosis in leukemic cell lines treated with captopril, trandolapril and losartan: A new role in the treatment of leukaemia for these agents

Renin–angiotensin system (RAS) in the bone marrow is related to proliferation and cellular differentiation. We investigated the effect of ACE inhibitors (ACEI) captopril (>1 mM) and trandolapril (>0.05 mM) and losartan (0.2 mM) on K562 cell line and K562 transfected with c-myc, bcl-x and bcl-2 (KmycB, Kbclx and Kbcl2 respectively). RAS components, proliferation, apoptosis and c-myc expression were analyzed. ACEI and losartan inhibited cell growth, decreased c-myc expression and increased apoptosis. These effects seem to be associated to angiotensin II-induced Smad activation. This work offers a new possible line of treatment for some acute myeloid leukemias and a new area of clinical research.

Endothelial Angiotensin II Generation Induced by Placenta-derived Factors From Preeclampsia

Hypersensitivity to angiotensin II contributes to the increased vasoconstriction in preeclampsia. In this study, we determined whether placenta-derived factors could affect endothelial cell angiotensin II generation.Our results showed that more angiotensin II was produced by endothelial cells treated with preeclampsia placental conditioned medium than the cells treated with normal conditioned medium or untreated controls. To determine which pathway, angiotensin-converting enzyme or nonangiotensin-converting enzyme angiotensin-generating enzyme/chymase, might be involved in preeclampsia conditioned medium induced angiotensin II generation, angiotensin-converting enzyme inhibitor captopril and chymotrypsin inhibitors were applied to the cell culture either separately or in combination. We found that chymotrypsin inhibitor, but not captopril, could attenuate the increased angiotensin II generation. To further test specific effects of the protease on endothelial cell angiotensin II generation, endothelial cells were grown in cell culture inserts and chymotrypsin was added to the upper chamber of the cell culture (apical exposure). The medium in the lower chamber (basal direction) was collected and measured for angiotensin II. Our results showed that apical exposure of endothelial cells to the protease resulted in a concentration-dependent increase in basal release of angiotensin II. Angiotensin II receptor-1 expression was also upregulated in cells treated with preeclampsia conditioned medium or chymotrypsin. This data suggest that placenta-derived factors may activate chymase-angiotensin pathway in endothelial cells. Moreover, increased endothelial cell basal release of angiotensin II in response to the protease stimulation further suggests that angiotensin II levels in the circulation may not necessarily reflect angiotensin II generation within the vascular wall.

Abstract 815: Recovery of Heart Function in Women with Severe Heart Failure from Peripartum Cardiomyopathy in Haiti

Peripartum cardiomyopathy (PPCM) is a form of heart failure from dilated cardiomyopathy with one of the greatest potentials for eventual full systolic function recovery. Traditional concepts of PPCM have held that if recovery did not occur by the six-month post-diagnosis mark, it would be unlikely to happen. This report shows that improvement and eventual full recovery may occur long after that initial period. PPCM patients have been identified from the Hôpital Albert Schweitzer PPCM Registry, Deschapelles, Haiti, from 2000 to 2008. All patients fully met diagnostic criteria for PPCM, which include onset of heart failure during the last month of pregnancy up to 5 months postpartum, absence of previous heart disease or other cause of heart failure, and echocardiographic criteria for systolic dysfunction. Recovery was defined as left ventricular (LV) ejection fraction (EF) greater than 50 percent. Echocardiography was carried out at initial diagnosis and at 6-month intervals, with a minimum of 24 months follow-up required for inclusion. Standard treatment included diuretics (lasix) and ACE-inhibitors (captopril), as determined by economic factors, which also excluded the routine use of beta-blockade. Thirty-two out of 116 (27.6 %) PPCM patients fully recovered LV systolic function. Mean follow-up was 35 months. The shortest time to recovery was 3 months and the longest time to recovery was 48 months. The number and cumulative percentage of recovery is shown in the following table : Table: Length of time required for recovery of left ventricular function in 32 Haitian PPCM patients, 2000–2008: Likelihood of recovery did not correlate with age (17–47 years), parity (1–10) or LV EF at diagnosis (12 to 40 %). Complete recovery of LV systolic function in PPCM often occurs after the first 6 to 12 months following diagnosis. It is important to continue treatment and follow-up sufficiently long to assure and document maximum benefit