[Metabolic pattern of pig hindgut bacteria on aromatic amino acids by an in vitro fermentation method].

Objective: This experiment was conducted to study different metabolic patterns of pig hindgut bacteria on aromatic amino acids by an in vitro fermentation method. Methods: Ileum, cecum and colon chyme in Duroc, Landrace and Yorkshire goods hybridization pigs were taken as inoculum. The single aromatic amino acid concentration was kept 10 mmol/L in fermentation flask. Then the fermentation flask was incubated at 37℃ for 24 h. Gas production was measured at 4, 8, 12, 16 and 24 h, and samples of fermentation collected at 0 h and 24 h were used to measure ammonia nitrogen NH3-N and microbial crude protein (MCP). Denaturing gradient gel electrophoresis (DGGE) and real-time PCR were used to monitor and quantify the development of bacteria community in zymotic fluid.[ Results: The concentrations of NH3-N and MCP were significantly affected by aromatic amino acids and intestinal segments (P<0.01). Intestinal segments also affected gas production (GP) significantly (P0.01). NH3-N, MCP and GP were affected by interaction of aromatic amino acids and intestinal segments. DGGE analysis showed bacteria of aromatic amino acids shared amount of bands together, especially similarity analysis of DGGE profile of Phe and Tyr in ileum, Tyr and Trp in colon were 87.9% and 80.5% separately. Shannon diversity indices analysis revealed that aromatic amino acids in cecum and colon varied significantly (P<0.05). Real-time PCR results showed that the quantity of total bacteria were affected by aromatic amino acids and intestinal segments significantly (P<0.05). Conclusion: The potential as proportion of different aromatic amino acids are different. Compared with Trp and Phe, the diversity of bacteria utilizing Tyr in cecum or colon is low; compared with Tyr and Trp, a large number of Phe participated in synthesizing bacteria.The fermentation pattern of specific aromatic amino acids in different intestinal segment was unique. Compared with ileum and cecum, much more aromatic amino acids participated in the synthesis of bacteria in colon.

Depletion of 14-3-3 protein exacerbates cardiac oxidative stress, inflammation and remodeling process via modulation of MAPK/NF-ĸB signaling pathways after streptozotocin-induced diabetes mellitus.

Diabetic cardiomyopathy is associated with increased oxidative stress and inflammation. Mammalian 14-3-3 proteins are dimeric phosphoserine-binding proteins that participate in signal transduction and regulate several aspects of cellular biochemistry. The aim of the study presented here was to clarify the role of 14-3-3 protein in the mitogen activated protein kinase (MAPK) and nuclear factor-kB (NF-κB) signaling pathway after experimental diabetes by using transgenic mice with cardiac-specific expression of a dominant-negative 14-3-3 protein mutant (DN 14-3-3). Significant p-p38 MAPK activation in DN 14-3-3 mice compared to wild type mice (WT) after diabetes induction and with a corresponding up regulation of its downstream effectors, p-MAPK activated protein kinase 2 (MAPKAPK-2). Marked increases in cardiac hypertrophy, fibrosis and inflammation were observed with a corresponding up-regulation of atrial natriuretic peptide, osteopontin, connective tissue growth factor, tumor necrosis factor α, interleukin (IL)-1ß, IL-6 and cellular adhesion molecules. Moreover, reactive oxygen species, left ventricular expression of NADPH oxidase subunits, p22 phox, p67 phox, and Nox4, and lipid peroxidation levels were significantly increased in diabetic DN 14-3-3mice compared to diabetic WT mice. Furthermore, myocardial NF-κB activation, inhibitor of kappa B-α degradation and mRNA expression of proinflammatory cytokines were significantly increased in DN 14-3-3 mice compared to WT mice after diabetes induction. In conclusion, our data suggests that depletion of 14-3-3 protein induces cardiac oxidative stress, inflammation and remodeling after experimental diabetes induction mediated through p38 MAPK, MAPKAPK-2 and NF-κB signaling.

A novel phenylpyridazinone, T-3999, reduces the progression of autoimmune myocarditis to dilated cardiomyopathy.

Regardless of the origin, injury to the heart can result in cardiomyocyte hypertrophy, fibrosis, and cell death. Myocarditis often progresses to dilated cardiomyopathy (DCM), a major cause of heart failure. In our study, we used a rat model of myosin-induced experimental autoimmune myocarditis (EAM), in which the heart transits from an acute phase (inflammatory myocarditis) to a chronic phase (remodeling and DCM). Our objective was to investigate whether T-3999, a novel phenylpyridazinone, can reduce this progression. Four weeks after myosin injection, T-3999 was administered daily to male Lewis rats in two doses (3 and 10 mg/kg, orally). Four weeks later, treatment was terminated; hemodynamic and echocardiographic measurements were performed; hearts were excised for histopathology and estimation of histamine, mRNA, and protein levels. Mortality rate was reduced by drug treatment. T-3999 reduced % fibrosis and tissue collagen III. Profibrotic markers-transforming growth factor-ß(1), tumor necrosis factor-α, and galectin-3--were attenuated by treatment. Mast cell density and degranulation, and tissue histamine concentration were also reduced. This indicates an anti-inflammatory effect of the drug in reducing fibrosis. Hypertrophy was reduced as reflected by reduced myocyte diameter and natriuretic peptide expression. T-3999 treatment increased the sarcoendoplasmic reticulum Ca(2+) ATPase 2 protein level and improved several cardiac function parameters. The reduction of the remodeling process and improvement in myocardial function suggest an effect of T-3999 in attenuating ventricular remodeling in post-myocarditis DCM.

Dominant-negative p38alpha mitogen-activated protein kinase prevents cardiac apoptosis and remodeling after streptozotocin-induced diabetes mellitus.

The p38 mitogen-activated protein kinase (MAPK) is activated during heart diseases that might be associated with myocardial damage and cardiac remodeling process. Diabetic cardiomyopathy is associated with increased oxidative stress and inflammation. The purpose of this study was to investigate the role of p38alpha MAPK after experimental diabetes by using transgenic (TG) mice with cardiac-specific expression of a dominant-negative mutant form of p38alpha MAPK. The elevation of blood glucose was comparable between the nontransgenic (NTG) and TG mice. The expression of phospho-p38 MAPK and phospho-MAPK-activated protein kinase 2 levels were significantly suppressed in TG mice heart than in NTG mice after diabetes induction. Left ventricular (LV) dimension in systole was smaller, and the percent fractional shortening was higher in diabetic TG mice compared with diabetic NTG mice. In addition, diabetic TG mice had reduced cardiac myocyte diameter, content of cardiac fibrosis, LV tissue expressions of atrial natriuretic peptide, transforming growth factor beta1, and collagen III compared with diabetic NTG mice. Moreover, LV expression of NADPH oxidase subunits, p22(phox), p67(phox), gp91(phox), and Nox4, reactive oxygen species and lipid peroxidation levels were significantly increased in diabetic NTG mice, but not in diabetic TG mice. Furthermore, myocardial apoptosis, the number of caspase-3-positive cells, and the downregulation of antiapoptotic protein Bcl-X(L) were less in diabetic TG mice compared with diabetic NTG mice. In conclusion, our data establish that p38alpha MAPK activity is required for cardiac remodeling after diabetes induction and suggest that p38alpha MAPK may promote cardiomyocyte apoptosis by downregulation of Bcl-X(L).

Effects of angiotensin receptor blocker on oxidative stress and cardio-renal function in streptozotocin-induced diabetic rats.

The important role of renin-angiotensin-aldosterone system blockade in the treatment of diabetes-induced cardiomyopathy and nephropathy has been clearly established. The present study examined the effect of angiotensin II type 1 receptor blocker (ARB) losartan on oxidative stress and cardio-renal function in streptozotocin (STZ)-induced diabetic rats. Losartan treatment resulted in improvement of myocardial function and suppressed cardiac and renal fibrosis compared with the diabetic group. Losartan treatment also down-regulated transforming growth factor-beta1 expression and attenuated the increased expression levels of p22(phox) and Nox4. Blood urea nitrogen (BUN) and urinary protein levels were increased significantly in the diabetic group. Losartan treatment significantly reduced proteinuria but not BUN level. Moreover, the elevated level of malondialdehyde in both heart and kidney were significantly reduced in the losartan-treated group compared with the diabetic group. These results provided evidence that oxidative stress plays a major role in diabetic rats induced by STZ, and treatment with the ARB might be beneficial for preventing the development and progression of diabetic disease.

Beneficial Effect of Food Substitute Containing L-Arginine, omega-3 Poly Unsaturated Fatty Acid, and Ribonucleic Acid in Preventing or Improving Metabolic Syndrome: A Study in 15 Overweight Patients and a Study of Fatty Acid Metabolism in Animals.

This study was conducted to investigate whether or not a food substitute (Dr. BAANs(R)) containing three bioactive components L-arginine, omega-3 polyunsaturated fatty acid, and ribonucleic acid, supplied orally to 15 overweight patients, may have efficacy to prevent or improve the metabolic syndrome of these patients. To provide supporting data for this clinical study, the in vivo fatty acid metabolism of obese mice was analyzed using (125)I labeled 15-(p-iodophenyl)-9-methylpentadecanoic acid (9MPA) in the tissues' lipid pool. After 3 months of intervention, the results showed that there were improvements observed in liver functions, lipid profiles and metabolic syndrome marker. Significant differences were also found in the values of blood pressure, body weight, percentage of body fat, and body mass index. In the animal study, the tissue uptake of (125)I-9MPA at 10 min after injection was higher in obese mice than in the control mice and the treatment with Dr. BAANs(R) in obese mice decreased the uptake significantly. The final product metabolite of p-iodophenylacetic acid in obese mice was increased significantly by the treatment. In conclusion, this food substitute may have a beneficial effect for the prevention or improvement of metabolic syndrome.

The Effects of gamma-Aminobutyric Acid, Vinegar, and Dried Bonito on Blood Pressure in Normotensive and Mildly or Moderately Hypertensive Volunteers.

The purpose of this study was to examine the effects of gamma-aminobutyric acid (GABA) in fermented drinking water prepared from sodium glutamate, vinegar, and dried bonito (FDWG) compared with placebo [vinegar and dried bonito without GABA (FDW)] and its safety in normotensive and mildly or moderately hypertensive volunteers. A double-blind, placebo-controlled, randomized study was conducted involving volunteers with normal (group-N) and mildly or moderately high (group-H) blood pressure (BP). After a pretreatment period of 2 weeks (weeks -2), the subjects received FDWG or FDW for 12 weeks followed by 4 weeks of no intake (weeks 16). In group-H, both FDWG and FDW significantly decreased systolic (SBP, -7.6 +/- 4.0 and -5.5 +/- 1.5 mmHg, p<0.05, respectively) and diastolic (DBP, -10.6 +/- 4.0 and -7.6 +/- 1.7 mmHg, p<0.01, respectively) BP compared to the baseline (0-week) value at 12 weeks, respectively. There were no abnormal changes in hematological or blood chemistry variables, urinalysis, heart rate, or body weight in the study groups. These findings indicated that vinegar and dried bonito with or without GABA might have an effect on BP in mildly or moderately hypertensive patients.

Edaravone Exerts Brain Protective Function by Reducing the Expression of AQP4, APP and Aß Proteins.

This study aims to investigate the changes of aquaporin-4 (AQP4), ß-amyloid precursor proteins (APP) and ß-amyloid (Aß) in brain tissues after cerebral ischemiareperfusion injury (CIRI), and evaluate the effect of edaravone. The Middle Cerebral Artery Occlusion was used to establish CIRI in rats. Rats were divided into control, model and edaravone groups. The neurological deficits in the model group were obvious and the neurological score increased compared to the control group, while the neurological deficits of the edaravone group were improved as the neurological score decreased compared to the model group. The number of pyramidel cells in the hippocampus of the model group was significantly decreased whereas edaravone could reverse this decrease. The model group had significantly higher levels of Aß, APP and AQP4 than the control group and edaravone group, suggesting that they might be involved in the neuronal cell damage. Meanwhile, the increased AQP4 might enhance the permeability of cells, and thus cause cell damage and neurological deficit. Conclusively, edaravone could reduce brain edema, protect neuronal cells and improve the neurological impairment of rats possibly by decreasing the expression of Aß, APP and AQP4. Therefore, edaravone may have the potential to treat neurodegenerative diseases (such as Alzheimer's disease).

Comparative effects of torasemide and furosemide in rats with heart failure.

It has been reported that torasemide but not furosemide, may block the renin-angiotensin-aldosterone system and therefore it might attenuate myocardial remodeling accompanied by left ventricular (LV) dysfunction. We therefore compared the therapeutic effects of torasemide, a long-acting loop diuretic, and furosemide, a short-acting one, on the progression of LV remodeling in a rat model of chronic heart failure (CHF) after experimental autoimmune myocarditis (EAM). CHF was elicited in Lewis rats by immunization with porcine cardiac myosin. Twenty-eight days after immunization, rats were treated for 28 days with torasemide, furosemide, or vehicle. We investigated the effects on metabolic and neurohumoral parameters, cardiac fibrosis and remodeling in EAM rats. Diuresis was increased dose dependently by both torasemide and furosemide, showed an equipotent natriuretic effect. The urinary potassium excretion was significantly increased with furosemide in comparison to torasemide. Myocardial functional parameters were significantly improved by torasemide. Conversely, these parameters did not change in rats receiving furosemide. Torasemide suppressed LV fibrosis, myocardial protein levels of transforming growth factor-beta1, collagen III, and aldosterone synthase and improved survival rate to the control level, but furosemide did not. Moreover, both pharmacological interventions significantly elevated plasma angiotensin II and decreased atrial natriuretic peptide in a dose-dependent manner. Our results demonstrate that compared with furosemide, torasemide treatment significantly improved survival rate, LV function and ameliorated the progression of cardiac remodeling in rats with CHF after EAM.

Torasemide, a long-acting loop diuretic, reduces the progression of myocarditis to dilated cardiomyopathy.

Torasemide is a long-acting loop diuretic that combines the effects of both furosemide and spironolactone. It has been reported that torasemide may block the renin-angiotensin-aldosterone system and therefore it might attenuate myocardial remodeling accompanied by left ventricular dysfunction. However, nothing is known about the effect of torasemide on myocardial remodeling in a rat model in which myosin-induced experimental autoimmune myocarditis might develop into dilated cardiomyopathy. Experimental autoimmune myocarditis was elicited in Lewis rats by immunization with porcine cardiac myosin. Twenty-eight days after immunization, we investigated the effects of torasemide on metabolic and neurohumoral parameters, cardiac fibrosis and remodeling in experimental autoimmune myocarditis rats. Diuresis was increased dose-dependently by torasemide; the urinary potassium and sodium excretion was significantly decreased and increased, respectively. Myocardial functional parameters measured by hemodynamic and echocardiographic studies were significantly improved by torasemide treatment in a dose-dependent manner. The area of fibrosis, myocyte size and the myocardial protein levels of transforming growth factor-beta1, collagen III, and aldosterone synthase were significantly decreased, and the sarcoplasmic reticulum Ca2+ ATPase2 protein level was significantly increased by torasemide treatment. Moreover, the plasma levels of angiotensin II and aldosterone were increased and atrial natriuretic peptide was decreased in a dose-dependent manner. Our results indicate that torasemide treatment significantly improved left ventricular function and ameliorated the progression of cardiac remodeling beyond its renal effects in rats with chronic heart failure after experimental autoimmune myocarditis.

Effects of nonpeptide vasopressin V2 antagonist tolvaptan in rats with heart failure.

Similar to other neurohormones that are activated in chronic heart failure (CHF), circulating arginine vasopressin (AVP) is elevated in patients with CHF. The precise role of AVP in the pathophysiology of cardiovascular disease is controversial. AVP is a peptide hormone that contributes to water retention and vasoconstriction in CHF through effects on V(2) and V(1a) receptors, respectively. In the present study, the effect of V(2) receptor (V(2)R) blockade using tolvaptan was assessed in a rat model of myosin-induced experimental autoimmune myocarditis. CHF was elicited in Lewis rats by immunization with porcine cardiac myosin, and 28 days after immunization rats were treated for 28 days with oral tolvaptan (3 or 10mg/(kg day)) or vehicle. CHF was characterized by left ventricular remodeling and impaired systolic and diastolic function. Chronic V(2)R blockade increased urine volume and urinary AVP excretion and decreased urine osmolality but had no natriuretic effect, and as a result caused increases in plasma osmolality and sodium. High doses of tolvaptan markedly elevated electrolyte-free water clearance. V(2)R blockade did not activate the renin-angiotensin system, not influence cardiac remodeling, cardiac function, or survival. The upregulation of aquaporin 2 protein in the kidney of CHF rats was inhibited by the administration of V(2)R antagonist. These results suggest that in a rat model of CHF, AVP plays a major role in water retention through the renal V(2)R.

Chymase inhibition reduces the progression to heart failure after autoimmune myocarditis in rats.

Chymase has been known as a local angiotensin II-generating enzyme in the cardiovascular system in dogs, monkeys, hamsters, and humans; however, recently it was reported that chymase also has various other functions. Therefore, we decided to examine whether the inhibition of chymase improves disease conditions associated with the pathophysiology of dilated cardiomyopathy in rats and its possible mechanism of action as rat chymase is unable to produce angiotensin II. We examined the effect of TY-51469, a novel chymase inhibitor (0.1 mg/kg/day [group CYI-0.1, n = 15] and 1 mg/kg/day [group CYI-1, n = 15]), in myosin-immunized postmyocarditis rats. Another group of myosin-immunized rats was treated with vehicle (group V, n = 15). Age-matched normal rats without immunization (group N, n = 10) were also included in the study. After 4 weeks of treatment, we evaluated cardiac function; area of fibrosis; fibrogenesis; levels of transforming growth factor (TGF)-beta1 and collagen III; hypertrophy and its marker, atrial natriuretic peptide (ANP); and mast cell activity. Survival rate and myocardial functions improved dose-dependently with chymase inhibitor treatment after myosin immunization. A reduction in the percent area of myocardial fibrosis, fibrogenesis, myocardial hypertrophy, and mast cell activity along with a reduction in TGF-beta1, collagen III, and ANP levels in the myocardium were noted in postmyocarditis rats that received chymase inhibitor treatment. The treatment also decreased myocardial aldosterone synthase levels in those animals. Inhibition of chymase reduces the pathogenesis of postmyocarditis dilated cardiomyopathy and progression to heart failure by preventing the pathological remodeling and residual inflammation in rats.

Amiodarone improves cardiac sympathetic nerve function to hold norepinephrine in the heart, prevents left ventricular remodeling, and improves cardiac function in rat dilated cardiomyopathy.

BACKGROUND: It is unclear how amiodarone therapy exerts its effects on left ventricular remodeling and cardiac sympathetic nerve function in chronic heart failure. We investigated long-term effects of amiodarone on rat dilated cardiomyopathy after healing of cardiac myosin-induced autoimmune myocarditis. METHODS AND RESULTS: Rats were treated with oral amiodarone or vehicle for 6 weeks. We determined cardiac function, left ventricular remodeling, and cardiac sympathetic nerve function with iodine-125-labeled metaiodobenzylguanidine ([I125]MIBG). Amiodarone treatment improved left ventricular pressure, central venous pressure, and rate of isovolumetric contraction and decreased ventricular weight (P<0.005). Expression of cytokine mRNA was unchanged; expression of atrial natriuretic peptide, collagen III, and transforming growth factor-beta1 mRNA was decreased in amiodarone-treated rats (P<0.05). Phenotype of myosin heavy chain was moved toward that of normal rats by amiodarone. Initial myocardial uptake of MIBG decreased by 67% (P<0.001) and washout rate accelerated by 221% in rats with chronic heart failure compared with normal rats. Whereas amiodarone decreased the initial uptake by 71% in normal rats, amiodarone decelerated the early washout and the late washout and improved the late myocardial distribution of MIBG in rats with chronic heart failure (257% compared with vehicle-treated rats with chronic heart failure; P<0.01). In proportion to MIBG distributions, cardiac tissue catecholamines were increased by amiodarone treatment. CONCLUSIONS: Long-term amiodarone treatment prevented left ventricular remodeling and improved cardiac function in rat dilated cardiomyopathy. Long-term amiodarone treatment also restored cardiac sympathetic tone to hold norepinephrine in the heart.

Glycogen synthase kinase 3beta together with 14-3-3 protein regulates diabetic cardiomyopathy: effect of losartan and tempol.

Glycogen synthase kinase (GSK) 3beta is a multifunctional protein that positively regulates myocardial apoptosis and negatively regulates hypertrophy. However, the role of GSK3beta in the diabetic myocardium is largely unknown. We found that GSK3beta became more active (less phosphorylated at serine 9) via decreased Akt phosphorylation, in parallel to c-Jun NH2 terminal kinase activation, which correlated with increased activated caspase 3 and myocardial apoptosis 3 days after streptozotocin (STZ) injection in mice. However, 28 days after STZ injection, GSK3beta became inactive, which correlated with the enhanced protein kinase C beta2 and p38 mitogen activated protein kinase expression, nuclear translocation of nuclear factor of activated T cells c3, cardiac hypertrophy and fibrosis. All of the above parameters were exacerbated in dominant-negative 14-3-3 transgenic mice. Our results suggest that GSK3beta together with 14-3-3 protein plays essential roles in the signaling of diabetic cardiomyopathy, and treatment with either losartan or tempol prevents these changes.

Effects of angiotensin II receptor blocker (candesartan) in daunorubicin-induced cardiomyopathic rats.

BACKGROUND: Daunorubicin is an anthracycline anti-tumor agent; anthracycline chemotherapy in cancer can cause severe cardiomyopathy leading to a frequently fatal congestive heart failure; the first-line treatment is diuretics and digoxin. Recently, angiotensin-converting enzyme inhibitors have been shown to be effective in the treatment of such toxicity. The purpose of this study was to investigate the effects of angiotensin II type-1 receptor antagonist (candesartan) in a rat model of daunorubicin-induced cardiomyopathy. METHODS: Rats were treated with a cumulative dose of 9 mg/kg body weight daunorubicin (i.v.). 28 days later, after the development of cardiomyopathy, animals were randomly assigned to candesartan-treated (5 mg/kg/day, p.o.) or vehicle-treated groups; age-matched normal rats were used as the control group. Candesartan treatment was continued for 28 days. Hemodynamic and echocardiographic parameters were measured, cardiac protein and mRNA were analyzed, and histopathological analyses of myocardial fibrosis, cell size and apoptosis were conducted. RESULTS: Following cardiomyopathy, left ventricular end diastolic pressure and left ventricular systolic dimension were significantly elevated; while % fractional shortening and Doppler E/A ratio were significantly reduced. Cardiomyopathic hearts showed significant increases in % fibrosis, % apoptosis, and myocyte diameter/body weight ratio; candesartan treatment reversed these changes. Fas-L protein overexpression in myopathic hearts was significantly suppressed by treatment with candesartan. Moreover, SERCA2 mRNA and protein expression were both down-regulated in myopathic hearts and restored to normal by candesartan treatment, significantly. CONCLUSIONS: Our findings suggest that candesartan treatment significantly improved the left ventricular function and reversed the myocardial pathological changes investigated in this model of daunorubicin-induced cardiomyopathy; suggesting its potentials in limiting daunorubicin cardiotoxicity.

Comparisons of blood biochemical parameters, digestive enzyme activities and volatile fatty acid profile between Meishan and Yorkshire piglets.

This study was conducted to compare physiological characteristics between Meishan and Yorkshire piglets in their early lives. Six healthy purebred Meishan sows and Yorkshire sows with close farrowing dates were used in this research. The piglets sucked their respective sow's milk for 14 days, then they were slaughtered to collect samples of blood, pancreas, contents of stomach, jejunum, cecum, colon as well as feces for analysis of blood biochemical parameters, digestive enzymes, and volatile fatty acid (VFA). The results showed that Yorkshire piglets had higher concentrations of high-density lipoprotein cholesterol (HDL-C) and total cholesterol (TC) (P < 0.05). Gastric lipase activity was higher in Meishan piglets but Yorkshire piglets had higher lactase activity (P < 0.05). The total VFA together with acetate and propionate in cecum and colon were higher in Meishan piglets than in Yorkshire piglets (P < 0.05), but acetate in jejunum and ratio of acetate to propionate in colon were lower in Meishan piglets than in Yorkshire piglets (P < 0.05). In conclusion, in early suckling period, significant differences exist in host metabolism and intestinal microbial metabolism between Meishan and Yorkshire piglets.

Telmisartan acts through the modulation of ACE-2/ANG 1-7/mas receptor in rats with dilated cardiomyopathy induced by experimental autoimmune myocarditis.

AIM: Recent findings have suggested that a therapeutic approach to amplify or stimulate the angiotensin-converting enzyme-2 [ACE-2]-angiotensin 1-7 [ANG 1-7] mas axis could provide protection against the development of cardiovascular diseases. We investigated the cardioprotective effects of telmisartan in rats with dilated cardiomyopathy [DCM] after experimental autoimmune myocarditis [EAM]. MAIN METHODS: DCM was elicited in Lewis rats by immunization with cardiac myosin, and twenty-eight days after immunization, the surviving Lewis rats were divided into two groups and treated with either telmisartan (10mg/kg/day) or vehicle. KEY FINDINGS: Telmisartan treatment effectively suppressed myocardial protein and mRNA expressions of inflammatory markers [CD68, iNOS, NF-kB, interleukin-1ß, interferon-γ, monocyte chemotactic protein-1] in comparison to vehicle-treated rats. In contrast, myocardial protein levels of ACE-2 and ANG 1-7 mas receptor were upregulated in the telmisartan-treated group compared with vehicle-treated rats. Telmisartan treatment significantly reduced fibrosis and hypertrophy and their marker molecules [OPN, CTGF, TGF-ß1 and collagens I and III and atrial natriuretic peptide and GATA-4, respectively] compared with those of vehicle-treated rats. In addition, telmisartan treatment significantly lowered the protein expressions of NADPH oxidase subunits p47phox, p67phox, and superoxide production when compared with vehicle-treated rats. Telmisartan treatment significantly decreased the expression levels of mitogen-activated protein kinase (MAPK) signaling molecules than with those of vehicle-treated rats. Also, telmisartan treatment significantly improved LV systolic and diastolic function. SIGNIFICANCE: These results indicate that telmisartan treatment significantly improved LV function and ameliorated the progression of cardiac remodeling through the modulation of ACE-2/ANG 1-7/Mas receptor axis in rats with DCM after EAM.

Olmesartan medoxomil treatment potently improves cardiac myosin-induced dilated cardiomyopathy via the modulation of ACE-2 and ANG 1-7 mas receptor.

Angiotensin converting enzyme-2 (ACE-2) is a monocarboxypeptidase that metabolises angiotensin (ANG)-II into angiotensin 1-7 (ANG 1-7), thereby functioning as a negative regulator of the renin-angiotensin system. We investigated whether treatment with ANG-II type 1 receptor blocker, olmesartan medoxomil is associated with the attenuation of cardiac myosin-induced dilated cardiomyopathy (DCM) through recently established new axis of ACE-2/ANG 1-7 mas receptor. DCM was elicited in Lewis rats by immunisation with cardiac myosin, and 28 days after immunisation, the surviving Lewis rats were divided into two groups and treated with either olmesartan medoxomil (10 mg/kg/day) or vehicle. Myocardial protein and mRNA levels of ACE-2, ANG 1-7 mas receptor were upregulated in the olmesartan-treated group compared with those of vehicle-treated DCM rats. In contrast, Olmesartan treatment effectively suppressed the myocardial protein and mRNA expressions of inflammatory markers in comparison to the vehicle-treated DCM rats. Olmesartan treatment significantly reduced fibrosis, hypertrophy and their marker molecules (OPN, CTGF, ANP and GATA-4, respectively), as well as matrix metalloproteinases compared with those of vehicle-treated DCM rats. Enhanced myocardial protein levels of phospho-p38 MAPK, phospho-JNK and phospho MAPKAPK-2 in the vehicle-treated DCM rats were prevented by olmesartan treatment. In addition, olmesartan treatment significantly lowered the protein expressions (Nitrotyrosine, p47phox and p67phox) and superoxide radical production compared with those of vehicle-treated DCM rats. Our present study might serve as a new therapeutic target of DCM in cardiovascular diseases and cardiac myosin-induced DCM via the modulation of ACE-2/ANG 1-7 mas receptor axis in rats with DCM after myosin-immunisation.

Olmesartan attenuates the development of heart failure after experimental autoimmune myocarditis in rats through the modulation of ANG 1-7 mas receptor.

Angiotensin-converting enzyme 2 (ACE-2) is a membrane-associated carboxy-peptidase catalyzes the conversion of the vasoconstrictor angiotensin (ANG)-II to the vasodilatory peptide ANG 1-7. In view of the expanding axis of the renin angiotensin system, we have investigated the cardioprotective effects of olmesartan (10mg/kg/day) in experimental autoimmune myocarditis. Olmesartan treatment effectively suppressed the myocardial protein expressions of inflammatory markers in comparison to the vehicle-treated rats. However, the protein and mRNA levels of ACE-2 and ANG 1-7, and its receptor Mas were upregulated in olmesartan treated group compared to vehicle-treated rats. Olmesartan medoxomil treatment significantly decreased the expression levels of phospho-p38 mitogen-activated protein kinase (MAPK), phospho-JNK, phospho-ERK and phospho-(MAPK) activated protein kinase-2 than with those of vehicle-treated rats. Moreover, vehicle-treated rats were shown to be up-regulated protein expressions of NADPH oxidase subunits (p47phox, p67phox and Nox-4), myocardial apoptotic markers and endoplasmic reticulum stress markers in comparison to those of normal and all these effects are expectedly down-regulated by an olmesartan. In addition, attenuated protein levels of phosphatidylinositol-3-kinase (PI3K) and phospho-Akt in the vehicle-treated EAM rats were prevented by olmesartan treatment. Our results suggest that beneficial effects of olmesartan treatment was more effective therapy in combating the inflammation, oxidative stress, apoptosis and signaling pathways associated with heart failure at least in part via the modulation of ANG 1-7 mas receptor.

Modulation of endoplasmic reticulum stress and cardiomyocyte apoptosis by mulberry leaf diet in experimental autoimmune myocarditis rats.

Mulberry is commonly used as silkworm diet and an alternative medicine in Japan and China, has recently reported to contain many antioxidative flavanoid compounds and having the free radical scavenging effects. Antioxidants reduce cardiac oxidative stress and attenuate cardiac dysfunction in animals with pacing-induced congestive heart failure. Hence we investigated the cardioprotective effect of mulberry leaf powder in rats with experimental autoimmune myocarditis. Eight-week-old Lewis rats immunized with cardiac myosin were fed with either normal chow or a diet containing 5% mulberry leaf powder and were examined on day 21. ML significantly decreased oxidative stress, myocyte apoptosis, cellular infiltration, cardiac fibrosis, mast cell density, myocardial levels of sarco/endo-plasmic reticulum Ca(2+) ATPase2, p22(phox), receptor for advanced glycation end products, phospho-p38 mitogen activated protein kinase, phospho-c-Jun NH(2)-terminal protein kinase, glucose regulated protein78, caspase12 and osteopontin levels in EAM rats. These results may suggest that mulberry diet can preserve the cardiac function in experimental autoimmune myocarditis by modulating oxidative stress induced MAPK activation and further afford protection against endoplasmic reticulum stress mediated apoptosis.