The angiotensin type 1 receptor antagonist valsartan attenuates pathological ventricular hypertrophy induced by hyperhomocysteinemia in rats

Promising Therapeutic Treatments for Cardiac Fibrosis: Herbal Plants and Their Extracts

Cardiac fibrosis is closely associated with multiple heart diseases, which are a prominent health issue in the global world. Neurohormones and cytokines play indispensable roles in cardiac fibrosis. Many signaling pathways participate in cardiac fibrosis as well. Cardiac fibrosis is due to impaired degradation of collagen and impaired fibroblast activation, and collagen accumulation results in increasing heart stiffness and inharmonious activity, leading to structure alterations and finally cardiac function decline. Herbal plants have been applied in traditional medicines for thousands of years. Because of their naturality, they have attracted much attention for use in resisting cardiac fibrosis in recent years. This review sheds light on several extracts from herbal plants, which are promising therapeutics for reversing cardiac fibrosis.

Hyperhomocysteinemia Promotes Cardiac Hypertrophy in Hypertension

Hyperhomocysteinemia (HHcy) is positively linked with several cardiovascular diseases; however, its role and underlying mechanisms in pathological cardiac hypertrophy are still unclear. Here, we focused on the effects and underlying mechanisms of HHcy in hypertensive cardiac hypertrophy, one of the most common and typical types of pathological cardiac hypertrophy. By a retrospective analysis of the association between HHcy and cardiac hypertrophy in a hypertensive cohort, we found that the prevalence of HHcy was higher in patients with hypertrophy and significantly associated with the presence of cardiac hypertrophy after adjusting for other conventional risk factors. In mice, HHcy induced by a methionine (2% wt/wt) diet feeding significantly promoted cardiac hypertrophy as well as cardiac inflammation and fibrosis induced by 3-week angiotensin ІІ (AngІІ) infusion (1000 ng/kg/min), while folic acid (0.006% wt/wt) supplement corrected HHcy and attenuated AngII-stimulated cardiac phenotypes. Mechanistic studies further showed that homocysteine (Hcy) exacerbated AngII-stimulated expression of Calcineurin and nuclear factor of activated T cells (NFAT), which could be attenuated by folic acid both in mice and in neonatal rat cardiomyocytes. Moreover, treatment with cyclosporin A, an inhibitor of Calcineurin, blocked Hcy-stimulated Calcineurin-NFAT signaling and hypertrophy in neonatal rat cardiomyocytes. In conclusion, our study indicates that HHcy promotes cardiac hypertrophy in hypertension, and Calcineurin-NFAT pathway might be involved in the pro-hypertrophic effect of Hcy.

Endoplasmic reticulum stress mediates homocysteine-induced hypertrophy of cardiac cells through activation of cyclic nucleotide phosphodiesterase 1C

Although the association of elevated homocysteine level with cardiac hypertrophy has been reported, the molecular mechanisms by which homocysteine induces cardiac hypertrophy remain inadequately understood. In this study we aim to uncover the roles of cyclic nucleotide phosphodiesterase 1 (PDE1) and endoplasmic reticulum (ER) stress and their relationship to advance the mechanistic understanding of homocysteine-induced cardiac cell hypertrophy. H9c2 cells and primary neonatal rat cardiomyocytes are exposed to homocysteine with or without ER stress inhibitor TUDCA or PDE1-specific inhibitor Lu AF58027, or transfected with siRNAs targeting PDE1 isoforms prior to homocysteine-exposure. Cell surface area is measured and ultrastructure is examined by transmission electron microscopy. Hypertrophic markers, PDE1 isoforms, and ER stress molecules are detected by q-PCR and western blot analysis. Intracellular cGMP and cAMP are measured by ELISA. The results show that homocysteine causes the enlargement of H9c2 cells, increases the expressions of hypertrophic markers β-MHC and ANP, upregulates PDE1A and PDE1C, promotes the expressions of ER stress molecules, and causes ER dilatation and degranulation. TUDCA and Lu AF58027 downregulate β-MHC and ANP, and alleviate cell enlargement. TUDCA decreases PDE1A and PDE1C levels. Silencing of PDE1C inhibits homocysteine-induced hypertrophy, whereas PDE1A knockdown has minor effect. Both cAMP and cGMP are decreased after homocysteine-exposure, while only cAMP is restored by Lu AF58027 and TUDCA. TUDCA and Lu AF58027 also inhibit cell enlargement, downregulate ANP, β-MHC and PDE1C, and enhance cAMP level in homocysteine-exposed primary cardiomyocytes. ER stress mediates homocysteine-induced hypertrophy of cardiac cells via upregulating PDE1C expression Cyclic nucleotide, especially cAMP, is the downstream mediator of the ER stress-PDE1C signaling axis in homocysteine-induced cell hypertrophy.

Homocysteine predicts vascular target organ damage in hypertension and may serve as guidance for first-line antihypertensive therapy

Homocysteine is an independent risk factor for cardiovascular and cerebrovascular disease and has been proposed to contribute to vascular dysfunction. We sought to determine in a real-world clinical setting whether homocysteine levels were associated with hypertension mediated organ damage (HMOD) and could guide treatment choices in hypertension. We performed a cross-sectional analysis of prospectively collected data in 145 hypertensive patients referred to our tertiary hypertension clinic at Royal Perth Hospital and analyzed the association of homocysteine with HMOD, renin-angiotensin-aldosterone system (RAAS), and RAAS blockade. The average age of participants was 56 ± 17 years, and there was a greater proportion of males than females (89 vs. 56). Regression analysis showed that homocysteine was significantly associated with PWV (β = 1.99; 95% CI 0.99-3.0; p < .001), albumin-creatinine ratio (lnACR: β = 1.14; 95% CI 0.47, 1.8; p < .001), 24 h urinary protein excretion (β = 0.7; 95% CI 0.48, 0.92; p < .001), and estimated glomerular filtration rate (β = -29.4; 95% CI -36.35, -22.4; p < .001), which persisted after adjusting for potential confounders such as age, sex, 24 h BP, inflammation, smoking, diabetes mellitus (DM), and dyslipidemia. A positive predictive relationship was observed between plasma homocysteine levels and PWV, with every 1.0 µmol/L increase in homocysteine associated with a 0.1 m/s increase in PWV. Homocysteine was significantly associated with elevated aldosterone concentration (β = 0.26; p < .001), and with attenuation of ACEi mediated systolic BP lowering and regression of HMOD compared to angiotensin receptor blockers in higher physiological ranges of homocysteine. Our results indicate that homocysteine is associated with hypertension mediated vascular damage and could potentially serve to guide first-line antihypertensive therapy.

Impact of renin angiotensin system inhibitors on homocysteine levels and platelets reactivity in patients on dual antiplatelet therapy

BACKGROUND AND AIMS

Dual antiplatelet therapy (DAPT) and Renin-angiotensin system inhibitors (RASi) represent the cornerstone in the treatment of patients undergoing percutaneous coronary interventions (PCI), mainly after an acute ischemic event. However, high-on treatment residual platelet reactivity (HRPR), is not infrequent despite optimal medical treatment. Homocysteine (Hcy) is a metabolite of methionine catabolism linked to atherothrombosis. Recently, a potential crosstalk between RAS and Hcy has been suggested, potentially favouring platelet aggregation and cardiovascular disease.Therefore, we aimed to investigate the impact of RASi on Hcy levels and platelet aggregation in patients on DAPT after PCI.

METHODS AND RESULTS

Patients undergoing PCI on DAPT with ASA plus an ADP-antagonist (clopidogrel, ticagrelor or prasugrel), were included. RASi comprised angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB). Aggregation tests were performed by Multiple Electrode Aggregometry. We included 1210 patients, of whom 862 (71.2%) were on treatment with RASi. Overall, DAPT composition was ASA+clopidogrel in 566 (46.8%) patients, ASA+ticagrelor in 428 (35.4%) and ASA+prasugrel in 216 (17.9%). Median values of Hcy were higher in RASi patients (p = 0.006), who displayed a higher percentage of Hcy above the median value (52.4% vs. 44.8%, p = 0.019, adjustedOR [95%CI] = 1.40 [1.04-1.88], p = 0.027). No differences in HRPR rate were found according to RASi use for ASPI test (3.6% vs. 3.3%, p = 0.88) and ADP test (25.6% vs. 24.3%,p = 0.62; adjustedOR [95%CI] = 1.23 [0.89-1.70], p = 0.220) and according to ADP-antagonist type. A direct linear relationship was observed between platelet reactivity and Hcy in both patients receiving RASi and untreated ones, with higher values of platelet aggregation being observed in patients with Hcy above the median, independently from RASi administration and DAPT strategy.

CONCLUSION

In patients on DAPT after PCI, RASi treatment did not emerge as an independent predictor of HRPR. However, the levels of Hcy were significantly elevated in patients on RASi and related to higher values of platelet reactivity, independently from the DAPT strategy.

Elevated Homocysteine Concentrations Decrease the Antihypertensive Effect of Angiotensin-Converting Enzyme Inhibitors in Hypertensive Patients

Objective—

We aimed to examine whether baseline homocysteine (Hcy) concentrations affect antihypertensive responses to enalapril treatment among previously untreated hypertensive patients (n=10 783) in the CSPPT (China Stroke Primary Prevention Trial).

Approach and Results—

After a 3-week run-in treatment with a daily dose of 10 mg enalapril, eligible hypertensive patients were randomly assigned to a double-blind daily treatment of a tablet of either enalapril (10 mg) and folic acid (0.8 mg) or enalapril (10 mg) alone for a median of 4.5 years. After the 3-week treatment period with enalapril alone, the systolic blood pressure–lowering effect was significantly reduced by 1.39 (95% confidence interval 0.40–2.37) and 3.25 (95% confidence interval 1.98–4.52) mm Hg, respectively, in those with baseline Hcy concentrations of 10 to 15 and ≥15 μmol/L ( P for trend <0.001) as compared with those with Hcy concentration of <10 μmol/L. Similar results were observed after a 15-week treatment period with enalapril alone. After a median 4.5-year enalapril-based antihypertensive treatment period, compared with those with Hcy concentration of <10 μmol/L, the systolic blood pressure–lowering effect was still significantly reduced by 0.77 (95% confidence interval 0.01–1.53) and 1.70 (95% confidence interval 0.72–2.68) mm Hg, respectively, in those with Hcy concentrations of 10 to 15 and ≥15 μmol/L ( P for trend <0.001). In addition, participants with higher baseline Hcy concentrations had persistently higher systolic blood pressure levels across the entire study treatment period. Similarly, baseline Hcy concentrations were inversely associated with diastolic blood pressure reduction during the short-term enalapril alone treatment. However, the inverse association between baseline Hcy and diastolic blood pressure reduction was attenuated and became insignificant after the long-term enalapril-based treatment period.

Conclusions—

Elevated Hcy concentrations significantly decreased the antihypertensive effect of the short-term and long-term enalapril-based antihypertensive treatment in previously untreated hypertensive patients.

Intermedin1-53 Protects Against Myocardial Fibrosis by Inhibiting Endoplasmic Reticulum Stress and Inflammation Induced by Homocysteine in Apolipoprotein E-Deficient Mice

AIM

Endoplasmic reticulum stress (ERS) and inflammation participate in cardiac fibrosis. Importantly, a novel paracrine/autocrine peptide intermedin_1-53 (IMD_1-53) in the heart inhibits myocardial fibrosis in rats. However, the mechanisms are yet to be fully elucidated.

METHODS

Myocardial fibrosis in apolipoprotein E-deficient (ApoE -/-) mice and neonatal rat cardiac fibroblasts (CFs) were induced using homocysteine (Hcy).

RESULTS

IMD_1-53 inhibited myocardial fibrosis in vivo and in vitro. Picrosirius red staining showed that IMD_1-53 reduced myocardial interstitial collagen deposition in ApoE-/- mice treated with Hcy and decreased the expression of myocardial collagen I and III, which was further verified in rat CFs. IMD_1-53 attenuated myocardial hypertrophy, as shown by cardiomyocyte cross-sectional area, ratio of heart weight to body weight, and mRNA levels of atrial natriuretic peptide and brain natriuretic peptide. IMD_1-53 inhibited the upregulation of ERS hallmarkers such as glucose-regulated protein 78 (GRP78), GRP94, activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1α, spliced-X-box-binding protein-1, protein kinase receptor-like ER kinase, and eukaryotic translation initiation factor 2α in mouse myocardium and rat CFs treated with Hcy. In addition, IMD_1-53 decreased the production of inflammatory factors such as tumor necrosis factor-α, monocyte chemotactic protein-1, interleukin-6 (IL-6), and IL-1β in the mouse myocardium and rat CFs treated with Hcy. Concurrently, IMD_1-53 ameliorated the expression of nuclear factor-κB, transforming growth factor-β1, and c-Jun N-terminal kinase in the mouse myocardium and rat CFs treated with Hcy.

CONCLUSIONS

IMD potentially protects against myocardial fibrosis induced by Hcy in ApoE-/- mice, possibly via attenuating myocardial ERS and inflammation.

Hyperhomocysteinemia accelerates collagen accumulation in the adventitia of balloon-injured rat carotid arteries via angiotensin II type 1 receptor

Recent studies suggest that hyperhomocysteinemia (HHcy) increases collagen type I accumulation in rat vascular adventitia after balloon injury and that Angiotensin II (Ang II) induces collagen synthesis in vascular adventitial fibroblasts. Reports also indicate that Ang II type1 receptor (AT1R) activation, mediated by homocysteine (Hcy) may contribute to collagen type 1 expression in mouse aortic endothelial cells. However, little is known about the possible mechanisms behind the relationship between Hcy and AT1R in adventitial remodeling. Thus, we investigated whether HHcy induces collagen accumulation via activation of AT1R in the adventitia. Male Sprague-Dawley (SD) rats were randomly divided into a control group and a 1% l-methionine-induced HHcy group. Balloon injury was performed after 12 experimental weeks and animals were sacrificed at 7, 14, and 28 days after injury. Collagen deposition and AT1R expression was measured with Western blot. Serum Hcy, adventitial collagen, and AT1R levels were higher in the HHcy group compared with the control group. Hcy time-dependently induced collagen type 1 and AT1R expression, with the highest induction observed at 48 h. Also, we observed that the AT1R blocker, valsartan, attenuated collagen type 1 and AT1R expression. HHcy exacerbates adventitial remodeling after balloon injury, and the underling mechanisms may be related to AT1R activity.

Hyperhomocysteinemia-induced Dyrk1a downregulation results in cardiomyocyte hypertrophy in rats

Cardiac hypertrophy has been demonstrated in rat models of hyperhomocysteinemia, a major risk factor for chronic heart failure. As one of the molecular pathway which leads to cardiac hypertrophy is mediated by the serine-threonine kinase DYRK1A, we have determined the expression of Dyrk1a in the heart of hyperhomocysteinemic rats and found that hyperhomocysteinemia in rats not only induced ventricular cardiomyocyte hypertrophy but also decreased protein Dyrk1a expression. The decreased expression of Dyrk1a could be consistent with decreased antihypertrophic effects of Dyrk1a leading to cardiomyocyte hypertrophy in case of hyperhomocysteinemia.

Ameliorative role of rosiglitazone in hyperhomocysteinemia-induced experimental cardiac hypertrophy

The present study has been designed to explore the beneficial effect of rosiglitazone, a peroxisome proliferator activated receptor-gamma agonist, in hyperhomocysteinemia-induced cardiac hypertrophy in rats. The hyperhomocysteinemia was induced in rats by feeding L-methionine (1.7 g/kg per day orally) for 8 weeks. The development of cardiac hypertrophy was assessed by measuring ratio of left ventricular weight to body weight, left ventricular wall thickness, cardiomyocyte diameter, and mean arterial blood pressure. The extent of fibrosis was checked by biochemical and histological assessment of collagen deposition. Moreover, the oxidative stress in heart was measured in terms of an increase in thiobarbituric acid reactive substances, superoxide anion generation, and decrease in reduced glutathione levels. The treatment with rosiglitazone (5 and 10 mg/kg per day orally) started from the first day of administration of L-methionine significantly abolished hyperhomocysteinemia-induced increase in left ventricular weight to body weight ratio, left ventricular wall thickness, cardiomyocyte diameter, collagen deposition, and oxidative stress without affecting serum homocysteine levels in rats. At high dose, rosiglitazone markedly reduced mean arterial blood pressure but at low dose, a significant reduction in mean arterial blood pressure was not observed in hyperhomocysteinemic rats. Hence, our results suggest that rosiglitazone provides benefit in hyperhomocysteinemia-induced cardiac hypertrophy and fibrosis in a dose-dependent manner and its protective action is independent of change in mean arterial blood pressure and serum homocysteine levels in rats.

Homocysteine thiolactone induces cardiac dysfunction: role of oxidative stress

This study investigates the cardiac functioning in male Wistar rats after treatments with methionine and homocysteine thiolactone (HcyT). The rats were distributed into 3 groups and treated for 8 weeks. Group I was the control (CO) group, given water, group II was treated with methionine, and group III with HcyT (100 mg/kg). Morphometric and functional cardiac parameters were evaluated by echocardiography. Superoxide dismutase (SOD), catalase, and glutathione S-transferase activities, chemiluminescence, thiobarbituric acid reactive substances, and immunocontent were measured in the myocardium. Hyperhomocysteinemiawas observed in rats submitted to the both treatments. The results showed diastolic function was compromised in HcyT group, seen by the increase of E/A (peak velocity of early (E) and late (A) diastolic filling) ratio, decrease in deceleration time of E wave and left ventricular isovolumic relaxation time. Myocardial performance index was increased in HcyT group and was found associated with increased SOD immunocontent. HcyT group demonstrated an increase in SOD, catalase, and glutatione S-transferase activity, and chemiluminescence and thiobarbituric acid reactive substances. Overall, these results indicated that HcyT induces a cardiac dysfunction and could be associated with oxidative stress increase in the myocardium.

Overexpression of dimethylarginine dimethylaminohydrolase protects against cerebral vascular effects of hyperhomocysteinemia

RATIONALE

Hyperhomocysteinemia is a cardiovascular risk factor that is associated with elevation of the nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA).

OBJECTIVE

Using mice transgenic for overexpression of the ADMA-hydrolyzing enzyme dimethylarginine dimethylaminohydrolase-1 (DDAH1), we tested the hypothesis that overexpression of DDAH1 protects from adverse structural and functional changes in cerebral arterioles in hyperhomocysteinemia.

METHODS AND RESULTS

Hyperhomocysteinemia was induced in DDAH1 transgenic (DDAH1 Tg) mice and wild-type littermates using a high methionine/low folate (HM/LF) diet. Plasma total homocysteine was elevated approximately 3-fold in both wild-type and DDAH1 Tg mice fed the HM/LF diet compared with the control diet (P<0.001). Plasma ADMA was approximately 40% lower in DDAH1 Tg mice compared with wild-type mice (P<0.001) irrespective of diet. Compared with the control diet, the HM/LF diet diminished endothelium-dependent dilation to 10 micromol/L acetylcholine in cerebral arterioles of both wild-type (12 + or - 2 versus 29 + or - 3%; P<0.001) and DDAH1 Tg (14 + or - 3 versus 28 + or - 2%; P<0.001) mice. Responses to 10 micromol/L papaverine, a direct smooth muscle dilator, were impaired with the HM/LF diet in wild-type mice (30 + or - 3 versus 45 + or - 5%; P<0.05) but not DDAH1 Tg mice (45 + or - 7 versus 48 + or - 6%). DDAH1 Tg mice also were protected from hypertrophy of cerebral arterioles (P<0.05) but not from accelerated carotid artery thrombosis induced by the HM/LF diet.

CONCLUSIONS

Overexpression of DDAH1 protects from hyperhomocysteinemia-induced alterations in cerebral arteriolar structure and vascular muscle function.

Hyperhomocysteinemia and Endothelial Dysfunction

Hyperhomocysteinemia (HHcy) is a significant and independent risk factor for cardiovascular diseases. Endothelial dysfunction (ED) is the earliest indicator of atherosclerosis and vascular diseases. We and others have shown that HHcy induced ED in human and in animal models of HHcy induced by either high-methionine load or genetic deficiency. Six mechanisms have been suggested explaining HHcy-induced ED. These include 1) nitric oxide inhibition, 2) prostanoids regulation, 3) endothelium-derived hyperpolarizing factors suppression, 4) angiotensin II receptor-1 activation, 5) endothelin-1 induction, and 6) oxidative stress. The goal of this review is to elaborate these mechanisms and to discuss biological and molecular events related to HHcy-induced ED.

Hyperhomocysteinemia, paraoxonase concentration and cardiovascular complications in Tunisian patients with nondiabetic renal disease

OBJECTIVES

Hyperhomocysteinemia is associated with an increased risk of cardiovascular diseases. We determine homocysteine levels (Hcy), paraoxonase (PON1) concentration and their relationship on cardiovascular complications in patients with chronic renal disease (CRD).

DESIGN AND METHODS

The study population included 100 CRD patients and 120 healthy controls. Renal function was assessed using the eGFR by the MDRD study equation. Patients were considered to have CRD when the eGFR was <60 mL/min/1.73 m(2). Hcy concentrations were determined by direct chemiluminescence assay. PON1 concentration was measured spectrophotometrically using phenylacetate as a substrate.

RESULTS

We found an increased Hcy levels and a decreased eGFR and PON1 concentration in CRD patients compared to the control group (P<0.001, P<0.001, P<0.01 respectively). Patients with cardiovascular complications showed an increased Hcy levels and a lower PON1 concentration than patients without cardiovascular complications (P<0.001, P<0.01 respectively).

CONCLUSION

We showed that hyperhomocysteinemia and low PON1 concentration are associated with CRD and markedly associated in patients with cardiovascular complications. Additional effects contribute to the severity of renal disease and increase the incidence of cardiovascular disease.

Synergism between AT1 receptor and hyperhomocysteinemia during vascular remodeling

BACKGROUND

Hyperhomocysteinemia (HHcy) is an independent risk factor of cardiovascular diseases. Extracellular signal-regulated kinase-1/2 (ERK-1/2) and the JAK/STAT pathway kinase, signal transducer and activator of transcription 3 (STAT3), are involved in matrix metalloproteinase-9 (MMP-9) induction and matrix remodeling. However, their role in homocysteine (Hcy)-mediated MMP-9 induction and matrix remodeling is unclear. Clinical and experimental evidence indicates that HHcy and activation of the renin-angiotensin system, mediated by angiotensin II type 1 (AT1) receptor, are involved in a variety of vascular pathologies. Despite this fact, the relationship between HHcy and activation of the renin-angiotensin system has not been comprehensively characterized. Therefore, we hypothesized that Hcy activates AT1 receptor that potentiates STAT3 via ERK-1/2 phosphorylation. STAT3 modulates target MMP-9 and collagen, resulting in vascular remodeling.

METHODS

Mouse aortic endothelial cells (MAEC) were treated with various doses of Hcy for different time periods. The levels of AT1 receptor, ERK-1/2, STAT3, MMP-9 and collagen type-1 were measured by immunoblot analyses. The activation of ERK-1/2 and STAT3 were determined by measuring ERK-1/2 phosphorylation and phosphoserine (727) STAT3.

RESULTS

Although Hcy dose-dependently induced AT1 receptor expression in the endothelial cells, a significant induction was observed at 100 microM at 48 h. We investigated Hcy-induced ERK-1/2 and STAT3 phosphorylation through AT1 receptor induction, and our results suggest that Hcy activated AT1 receptor which led to ERK-1/2 and STAT3 phosphorylation. In addition, findings of this study suggest that Hcy-mediated STAT3 activation regulated MMP-9 and collagen type-1. However, AT1 receptor blocker, valsartan, and the specific STAT3 inhibitor peptide attenuated MMP-9 and collagen type-1 induction.

CONCLUSIONS

These findings demonstrate for the first time the contribution of AT1 receptor in HHcy-induced atherosclerotic diseases; Hcy-induced activation of AT1 receptor involves MMP-9 and collagen type-1 modulation using ERK-1/2 and STAT3 signaling cascades.

An angiotensin II receptor antagonist reduces inflammatory parameters in two models of colitis

Little is known about the effects of the pro-inflammatory hormone Angiotensin II (Ang II) in inflammatory bowel disease. The aim of this study was to evaluate the effect of valsartan (Diovan), an Ang II receptor antagonist, in two models of colitis.

METHODS

Colitis was induced in Sprague-Dawley rats by administration of trinitrobenzene sulfonic acid (TNBS; 30 mg in 50% ETOH i.c.) or 5% Dextran Sulphate Sodium (DSS) in drinking water ad libitum for 5 days. Valsartan was administered orally in drinking water (160 mg/L) during thirty days prior to the induction of the colitis, and for 5 days after. All animals were evaluated for weight change, diarrhea, myeloperoxidase activity, macroscopic and microscopic damage. Cytokine levels in the colon were measured by ELISA, real-time RT-PCR and immunohistochemistry.

RESULTS

In the TNBS model, valsartan reduced the macroscopic damage score, significantly decreased the microscopic damage (p<0.01), and accelerated weight gain after colitis. In the DSS-colitis model, valsartan-treated animals had less diarrhea and microscopic damage. Valsartan reduced the protein levels of TGFbeta (p<0.05), and IL-18 in the TNBS model, and led to over expression of IL-10 mRNA in the DSS model.

CONCLUSION

These data demonstrate a possible anti-inflammatory effect for valsartan in colitis.