Folic acid and vitamin B(12) supplementation attenuates isoprenaline-induced myocardial infarction in experimental hyperhomocysteinemic rats

Folic acid alleviates lead acetate-mediated cardiotoxicity by down-regulating the expression levels of Nrf2, HO-1, GRP78, and CHOP proteins

The purpose of this study was to explore the interventional effects of folic acid on the heart damage caused by lead acetate exposure. Twenty-four 60-day-old male Sprague-Dawley (SD) rats were randomly divided into 4 groups with 6 rats in each group. The control group (C group) was normal rats; the lead exposure group (L group) rats drank 0.2% lead acetate solution freely for 14 days. The rats in the intervention group (T group) were given 0.2% lead acetate solution for 14 days, respectively, and 0.4 mg/kg BW folic acid solution was given to the rats by gavage on the 7th day of lead administration. The rats in the folic acid group (group E) were given 0.4 mg/kg BW folic acid solution by gavage. To weigh rat body weight and heart weight, calculate heart index, and observe the expression level of nuclear factor erythroid 2-related factor 2(Nrf2), heme oxygenase 1(HO-1), glucose-regulated protein 78/binding immunoglobulin protein (GRP78), and C/EBP-homologous protein (CHOP) by immunofluorescence method. The results showed that compared with group C, serum lead levels in group L and T were significantly increased (P < 0.05); superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-PX) levels in group L were significantly decreased (P < 0.05), and malondialdehyde (MDA) content was significantly higher increased (P < 0.05), and the GSH-PX content in group T were significantly increased in group L (P < 0.05), and the MDA content in group T was significantly lower than that in group L (P < 0.05). Compared with group C, the expression of Nrf2, HO-1, GRP78, and CHOP in group L increased significantly, and the difference was statistically significant (P < 0.05). Compared with the L group, the expression of Nrf2, HO-1, GRP78, and CHOP in the T group was reduced. Therefore, folic acid has a certain protective effect on the oxidative damage of lead-exposed rat heart tissue. Lead exposure will increase ROS, NO, MDA, and other oxidizing substances and reduce the level of GSH, SOD, CAT, GPx, and other antioxidant factors, which will lead to cardiac hypertrophy, cardiac index increase, oxidative stress, Nrf2, and HO-1. The expression of stress-related proteins such as GRP78 and CHOP also increased, leading to cardiomyocyte apoptosis. After a folic acid intervention, these changes can be significantly reversed.

Metabolic Therapy of Heart Failure: Is There a Future for B Vitamins?

Heart failure (HF) is a plague of the aging population in industrialized countries that continues to cause many deaths despite intensive research into more effective treatments. Although the therapeutic arsenal to face heart failure has been expanding, the relatively short life expectancy of HF patients is pushing towards novel therapeutic strategies. Heart failure is associated with drastic metabolic disorders, including severe myocardial mitochondrial dysfunction and systemic nutrient deprivation secondary to severe cardiac dysfunction. To date, no effective therapy has been developed to restore the cardiac energy metabolism of the failing myocardium, mainly due to the metabolic complexity and intertwining of the involved processes. Recent years have witnessed a growing scientific interest in natural molecules that play a pivotal role in energy metabolism with promising therapeutic effects against heart failure. Among these molecules, B vitamins are a class of water soluble vitamins that are directly involved in energy metabolism and are of particular interest since they are intimately linked to energy metabolism and HF patients are often B vitamin deficient. This review aims at assessing the value of B vitamin supplementation in the treatment of heart failure.

Effectiveness of Some Vitamins in the Prevention of Cardiovascular Disease: A Narrative Review

By virtue of their regulatory role in various metabolic and biosynthetic pathways for energy status and cellular integrity, both hydro-soluble and lipo-soluble vitamins are considered to be involved in maintaining cardiovascular function in health and disease. Deficiency of some vitamins such as vitamin A, B₆, folic acid, C, D, and E has been shown to be associated with cardiovascular abnormalities whereas supplementation with these vitamins has been claimed to reduce cardiovascular risk for hypertension, atherosclerosis, myocardial ischemia, arrhythmias, and heart failure. However, the data from several experimental and clinical studies for the pathogenesis of cardiovascular disease due to vitamin deficiency as well as therapy due to different vitamins are conflicting. In this article, we have attempted to review the existing literature on the role of different vitamins in cardiovascular disease with respect to their deficiency and supplementation in addition to examining some issues regarding their involvement in heart disease. Although both epidemiological and observational studies have shown some merit in the use of different antioxidant vitamins for the treatment of cardiovascular disorders, the results are not conclusive. Furthermore, in view of the complexities in the mechanisms of different cardiovascular disorders, no apparent involvement of any particular vitamin was seen in any specific cardiovascular disease. On the other hand, we have reviewed the evidence that deficiency of vitamin B₆ promoted KCl-induced Ca²⁺ entry and reduced ATP-induced Ca²⁺-entry in cardiomyocytes in addition to decreasing sarcolemmal (SL) ATP binding. The active metabolite of vitamin B₆, pyridoxal 5′-phosphate, attenuated arrhythmias due to myocardial infarction (MI) as well as cardiac dysfunction and defects in the sarcoplasmic reticulum (SR) Ca²⁺-transport in the ischemic-reperfused hearts. These observations indicate that both deficiency of some vitamins as well as pretreatments with different vitamins showing antioxidant activity affect cardiac function, metabolism and cation transport, and support the view that antioxidant vitamins or their metabolites may be involved in the prevention rather than the therapy of cardiovascular disease.

Translocator Protein Modulation by 4'-Chlorodiazepam and NO Synthase Inhibition Affect Cardiac Oxidative Stress, Cardiometabolic and Inflammatory Markers in Isoprenaline-Induced Rat Myocardial Infarction

The possible cardioprotective effects of translocator protein (TSPO) modulation with its ligand 4'-Chlorodiazepam (4'-ClDzp) in isoprenaline (ISO)-induced rat myocardial infarction (MI) were evaluated, alone or in the presence of L-NAME. Wistar albino male rats (b.w. 200-250 g, age 6-8 weeks) were divided into 4 groups (10 per group, total number N = 40), and certain substances were applied: 1. ISO 85 mg/kg b.w. (twice), 2. ISO 85 mg/kg b.w. (twice) + L-NAME 50 mg/kg b.w., 3. ISO 85 mg/kg b.w. (twice) + 4'-ClDzp 0.5 mg/kg b.w., 4. ISO 85 mg/kg b.w. (twice) + 4'-ClDzp 0.5 mg/kg b.w. + L-NAME 50 mg/kg b.w. Blood and cardiac tissue were sampled for myocardial injury and other biochemical markers, cardiac oxidative stress, and for histopathological evaluation. The reduction of serum levels of high-sensitive cardiac troponin T hs cTnT and tumor necrosis factor alpha (TNF-α), then significantly decreased levels of serum homocysteine Hcy, urea, and creatinine, and decreased levels of myocardial injury enzymes activities superoxide dismutase (SOD) and glutathione peroxidase (GPx) as well as lower grades of cardiac ischemic changes were demonstrated in ISO-induced MI treated with 4'-ClDzp. It has been detected that co-treatment with 4'-ClDzp + L-NAME changed the number of registered parameters in comparison to 4'-ClDzp group, indicating that NO (nitric oxide) should be important in the effects of 4'-ClDzp.

Molecules and Mechanisms to Overcome Oxidative Stress Inducing Cardiovascular Disease in Cancer Patients

Reactive oxygen species (ROS) are molecules involved in signal transduction pathways with both beneficial and detrimental effects on human cells. ROS are generated by many cellular processes including mitochondrial respiration, metabolism and enzymatic activities. In physiological conditions, ROS levels are well-balanced by antioxidative detoxification systems. In contrast, in pathological conditions such as cardiovascular, neurological and cancer diseases, ROS production exceeds the antioxidative detoxification capacity of cells, leading to cellular damages and death. In this review, we will first describe the biology and mechanisms of ROS mediated oxidative stress in cardiovascular disease. Second, we will review the role of oxidative stress mediated by oncological treatments in inducing cardiovascular disease. Lastly, we will discuss the strategies that potentially counteract the oxidative stress in order to fight the onset and progression of cardiovascular disease, including that induced by oncological treatments.

Oxidative Stress in Cardiovascular Diseases

Reactive oxygen species (ROS) are subcellular messengers in signal transductions pathways with both beneficial and deleterious roles. ROS are generated as a by-product of mitochondrial respiration or metabolism or by specific enzymes such as superoxide dismutases, glutathione peroxidase, catalase, peroxiredoxins, and myeloperoxidases. Under physiological conditions, the low levels of ROS production are equivalent to their detoxification, playing a major role in cellular signaling and function. In pathological situations, particularly atherosclerosis or hypertension, the release of ROS exceeds endogenous antioxidant capacity, leading to cell death. At cardiovascular levels, oxidative stress is highly implicated in myocardial infarction, ischemia/reperfusion, or heart failure. Here, we will first detail the physiological role of low ROS production in the heart and the vessels. Indeed, ROS are able to regulate multiple cardiovascular functions, such as cell proliferation, migration, and death. Second, we will investigate the implication of oxidative stress in cardiovascular diseases. Then, we will focus on ROS produced by NAPDH oxidase or during endothelial or mitochondrial dysfunction. Given the importance of oxidative stress at the cardiovascular level, antioxidant therapies could be a real benefit. In the last part of this review, we will detail the new therapeutic strategies potentially involved in cardiovascular protection and currently under study.

M3, a 1,4-Dihydropyridine Derivative and Mixed L-/T-Type Calcium Channel Blocker, Attenuates Isoproterenol-Induced Toxicity in Male Wistar Rats

Recent evidence indicates that Ca²⁺ dysregulation is involved in the pathogenesis of isoproterenol (ISP)-induced biochemical toxicity and associated oxidative stress. In this study, we investigated the chemopreventive benefit of M3, a 1,4-dihydropyridine calcium channel blocker, against ISP-induced toxicity in male Wistar rats. Adult rats were divided into eight groups of six rats/group. Groups 1-5 received normal saline (control, 10 mL/kg/day, p.o.), ISP (85 mg/kg/day, s.c.), M3 lower dose (M3LD, 5 mg/kg, p.o.), M3 upper dose (M3UD, 20 mg/kg/day, p.o.), and Nifedipine (NFD, 20 mg/kg/day, p.o.), respectively. Others (groups 6-8) were pretreated with either M3LD, M3UD or NFD one hour before ISP administration. All rats were sacrificed 24 h after the last administration and changes in biochemical, hematological, and antioxidant parameters were assessed. Histologic examination of the heart, liver and kidney was also conducted. ISP elevated (p < 0.05) Ca²⁺, alanine aminotransferase, lactate dehydrogenase, triglycerides, and low-density lipoprotein levels when compared with control. Similarly, ISP increased levels of markers of renal function (p < 0.01), C-reactive protein (148.1%) and myocardial malondialdehyde (MDA, 88.7%) and tumor necrosis factor-alpha (109.2%). Platelet level was reduced (p < 0.05) in the ISP-intoxicated control rats. M3 exhibited antioxidant property, reduced levels of triglycerides, MDA and improved biochemical and hematological alterations associated with ISP toxicity. M3, however, was not effective in restoring histological changes that characterized ISP toxicity at the doses used. M3 offers chemopreventive benefits against ISP toxicity possibly through L-/T-type calcium channels blockade and modulatory actions on biochemical and antioxidant homeostasis.

Low Vitamin B12 and Lipid Metabolism: Evidence from Pre-Clinical and Clinical Studies

Obesity is a worldwide epidemic responsible for 5% of global mortality. The risks of developing other key metabolic disorders like diabetes, hypertension and cardiovascular diseases (CVDs) are increased by obesity, causing a great public health concern. A series of epidemiological studies and animal models have demonstrated a relationship between the importance of vitamin B12 (B12) and various components of metabolic syndrome. High prevalence of low B12 levels has been shown in European (27%) and South Indian (32%) patients with type 2 diabetes (T2D). A longitudinal prospective study in pregnant women has shown that low B12 status could independently predict the development of T2D five years after delivery. Likewise, children born to mothers with low B12 levels may have excess fat accumulation which in turn can result in higher insulin resistance and risk of T2D and/or CVD in adulthood. However, the independent role of B12 on lipid metabolism, a key risk factor for cardiometabolic disorders, has not been explored to a larger extent. In this review, we provide evidence from pre-clinical and clinical studies on the role of low B12 status on lipid metabolism and insights on the possible epigenetic mechanisms including DNA methylation, micro-RNA and histone modifications. Although, there are only a few association studies of B12 on epigenetic mechanisms, novel approaches to understand the functional changes caused by these epigenetic markers are warranted.

Folic acid ameliorates celecoxib cardiotoxicity in a doxorubicin heart failure rat model

CONTEXT

The cardiotoxic effect of selective cyclo-oxygenase-2 inhibitors is well known. While rofecoxib and valdecoxib have been withdrawn, celecoxib remains on the market. Folic acid, a naturally occurring vitamin, has been shown to reduce myocardial ischemia and post-reperfusion injury in rats.

OBJECTIVE

This study examined the cardiac effects of celecoxib and folic acid on doxorubicin-induced cardiomyopathy in rats.

MATERIALS AND METHODS

Cardiomyopathy was induced in male Wistar rats with six intraperitoneal injections of 2.5 mg/kg doxorubicin over a period of two weeks. The effect of 28 days of celecoxib (100 mg/kg/day) and its combination with folic acid (10 mg/kg/day) was studied on doxorubicin-induced cardiomyopathy according to serum lactate dehydrogenase (LDH), creatine kinase (CK-MB), troponin-T (Tn-T), tumor necrosis factor alpha (TNF-α), cardiac thiobarbituric acid reactive substance (TBARS), and glutathione (GSH) levels as well as systolic blood pressure (SBP), heart rate (HR) and ultrastructural studies.

RESULTS

Celecoxib cardiotoxicity was manifested by significant increases in the LDH, Tn-T, TNF-α, CK-MB, SBP, HR (p < 0.001) and TBARS (p < 0.01) levels and a significant decrease in the GSH (p < 0.05) level when used alone or administered with doxorubicin. However, the combination of folic acid with celecoxib caused a significant reversal of these parameters and reduced the cardiotoxicity of celecoxib that was aggravated by doxorubicin. The ultrastructural study also revealed myocardial protection with this combination.

DISCUSSION AND CONCLUSION

Folic acid protects against the cardiotoxic effects of celecoxib, which are aggravated in the presence of doxorubicin. Folic acid may act as a useful adjunct in patients who are taking celecoxib.

Potential involvement of PPAR α activation in diminishing the hepatoprotective effect of fenofibrate in NAFLD: Accuracy of non- invasive panel in determining the stage of liver fibrosis in rats

BACKGROUND

Although Fenofibrate (FF) is a hypolipedmic drug and one of the PPARα agonists which is a drug target for non alcoholic liver disease (NAFLD), no studies had investigated its potential hepatic effects in such cases.

AIM

To compare between the effect of FF and Gemfibrozil (GF) on the prognosis of NAFLD in rats.

METHODS

Sixty four rats were used and classified into two main groups. Group I (treated for 6 weeks): naïve, FF, GF groups and Group II (treated for 14 weeks and drugs were added at the last 6 weeks): Control, high fat diet (HFD) untreated, HFD+FF, HFD+FF+folic acid (FA) and HFD+GF groups. Body weight (BW), liver index (LI), renal perfusion test (RPT), glomerular filtration rate (GFR), serum creatinine (S.cr), plasma homocysteine (Hcy), liver function, non invasive markers of fibrosis and histopathology were done.

RESULTS

HFD produced significant increase (P<0.05) in BW, LI, S.cr, plasma Hcy, lipid profile and liver enzymes. It showed significant (P<0.05) decrease in GFR and RPT. These findings were correlated to the histopathology. FF through its effect on GFR and renal function induced significant increase in plasma Hcy and that decreased its effectiveness in managing NAFLD associated with hyperlipidemia. The addition of FA improved significantly its hypolipidemic and hepatotoxic effects.GF showed none of the above FF effects and this may be due to its low affinity to PPAR α.

CONCLUSIONS

There is preference of adding FA to FF or using GF instead in cases of NAFLD. Moreover, this work implies the enhanced liver fibrosis (ELF) panel diagnostic performance in diagnosis of any and moderate degree of fibrosis in rats with NAFLD.

Protective role of curcumin in myocardial oxidative damage induced by isoproterenol in rats

This study was designed to investigate the effect of oral curcumin pretreatment (200 mg/kg) on isoproterenol-induced myocardial injury in rats. Isoproterenol (85 mg/kg, s.c., in two divided doses at 24 h intervals) administration induced a statistically significant increase ( P < 0.01) in serum lactate dehydrogenase, creatine kinase, aspartate transaminase, and alanine transaminase activities and significant increase ( P < 0.01) in myocardial lipid peroxides levels as compared to vehicle control rats. Furthermore, significant depletion ( P < 0.01) of myocardial endogenous antioxidants viz. superoxide dismutase, catalase, and tissue glutathione levels were also found in the pathogenic control group, that is, isoproterenol only treated animals. Curcumin (200 mg/kg) pretreatment for 20 days in isoproterenol treated rats significantly lowered ( P < 0.01) the serum lactate dehydrogenase, creatine kinase, aspartate transaminase, alanine transaminase, and myocardial lipid peroxides levels and increased the levels of myocardial endogenous antioxidants (superoxide dismutase, catalase, and tissue glutathione) as compared to pathogenic control rats. Furthermore, histological examination of rat’s heart section confirmed myocardial injury with isoproterenol administration and near normal pattern with curcumin pretreatment. The results of our study provide clear evidence that the curcumin pretreatment enhances the antioxidant defense against isoproterenol-induced oxidative myocardial injury in rats and exhibit cardioprotective property.

Hesperidin produces cardioprotective activity via PPAR-γ pathway in ischemic heart disease model in diabetic rats

The present study investigated the effect of hesperidin, a natural flavonoid, in cardiac ischemia and reperfusion (I/R) injury in diabetic rats. Male Wistar rats with diabetes were divided into five groups and were orally administered saline once daily (IR-sham and IR-control), Hesperidin (100 mg/kg/day; IR-Hesperidin), GW9962 (PPAR-γ receptor antagonist), or combination of both for 14 days. On the 15^th day, in the IR-control and IR-treatment groups, rats were subjected to left anterior descending (LAD) coronary artery occlusion for 45 minutes followed by a one-hour reperfusion. Haemodynamic parameters were recorded and rats were sacrificed; hearts were isolated for biochemical, histopathological, ultrastructural and immunohistochemistry. In the IR-control group, significant ventricular dysfunctions were observed along with enhanced expression of pro-apoptotic protein Bax. A decline in cardiac injury markers lactate dehydrogenase activity, CK-MB and increased content of thiobarbituric acid reactive substances, a marker of lipid peroxidation, and TNF-α were observed. Hesperidin pretreatment significantly improved mean arterial pressure, reduced left ventricular end-diastolic pressure, and improved both inotropic and lusitropic function of the heart (+LVdP/dt and –LVdP/dt) as compared to IR-control. Furthermore, hesperidin treatment significantly decreased the level of thiobarbituric acid reactive substances and reversed the activity of lactate dehydrogenase towards normal value. Hesperidin showed anti-apoptotic effects by upregulating Bcl-2 protein and decreasing Bax protein expression. Additionally, histopathological and ultrastructural studies reconfirmed the protective action of hesperidin. On the other hand, GW9662, selective PPAR-γ receptor antagonist, produced opposite effects and attenuated the hesperidin induced improvements. The study for the first time evidence the involvement of PPAR-γ pathway in the cardioprotective activity of hesperidin in I/R model in rats.

Effects of rosuvastatin on the production and activation of matrix metalloproteinase-2 and migration of cultured rat vascular smooth muscle cells induced by homocysteine

OBJECTIVE

To test the influence of homocysteine on the production and activation of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2) and on cell migration of cultured rat vascular smooth muscle cells (VSMCs). Also, to explore whether rosuvastatin can alter the abnormal secretion and activation of MMP-2 and TIMP-2 and migration of VSMCs induced by homocysteine.

METHODS

Rat VSMCs were incubated with different concentrations of homocysteine (50-5000 μmol/L). Western blotting and gelatin zymography were used to investigate the expressions and activities of MMP-2 and TIMP-2 in VSMCs in culture medium when induced with homocysteine for 24, 48, and 72 h. Transwell chambers were employed to test the migratory ability of VSMCs when incubated with homocysteine for 48 h. Different concentrations of rosuvastatin (10(-9)-10(-5) mol/L) were added when VSMCs were induced with 1000 μmol/L homocysteine. The expressions and activities of MMP-2 and TIMP-2 were examined after incubating for 24, 48, and 72 h, and the migration of VSMCs was also examined after incubating for 48 h.

RESULTS

Homocysteine (50-1000 μmol/L) increased the production and activation of MMP-2 and expression of TIMP-2 in a dose-dependent manner. However, when incubated with 5000 μmol/L homocysteine, the expression of MMP-2 was up-regulated, but its activity was down-regulated. Increased homocysteine-induced production and activation of MMP-2 were reduced by rosuvastatin in a dose-dependent manner whereas secretion of TIMP-2 was not significantly altered by rosuvastatin. Homocysteine (50-5000 μmol/L) stimulated the migration of VSMCs in a dose-dependent manner, but this effect was eliminated by rosuvastatin.

CONCLUSIONS

Homocysteine (50-1000 μmol/L) significantly increased the production and activation of MMP-2, the expression of TIMP-2, and the migration of VSMCs in a dose-dependent manner. Additional extracellular rosuvastatin can decrease the excessive expression and activation of MMP-2 and abnormal migration of VSMCs induced by homocysteine.

Putative antioxidant property of sesame oil in an oxidative stress model of myocardial injury

BACKGROUND

Sesame oil is a potent antioxidant dietary source for human health. Oxidative stress through generation of free radicals damages the myocardium in different experimental condition. The present research was designed to evaluate the antioxidant property of chronic oral administration of sesame oil against isoproterenol induced myocardial injury.

METHODS AND RESULTS

Male Wistar albino rats were randomly divided into five groups (n = 6) and treated as per treatment protocol with two different doses of sesame oil (5 and 10 ml/kg b.w.) orally for thirty days. At the end of the treatment all the rats (except control rats) were administered with isoproterenol (85 mg/kg) two consecutive days and subjected to biochemical and histopathological estimation. Isoproterenol (group ISO) induced the oxidative myocardial damage via alteration in the endogenous antioxidant enzymes and myocardial marker enzymes. Sesame oil in both the dose (group S1 and S2) shows protective mechanism via decreasing thiobarbituric acid reactive substance (TBARS) and enhancing the endogenous antioxidant enzymes (reduced glutathione (GSH), superoxide dismutase (SOD) and Catalase). Sesame oil also increased the lactate dehydrogenase (LDH), creatine kinase (CK) and aspartate transaminase (AST) as a myocardial marker enzyme in heart homogenate. As histologically evident isoproterenol induced myocardial injury was well preserved by the chronic administration of sesame oil. The protective role of sesame oil was compared with the reference standard α-tocopherol (group S3) also showing the similar effect.

CONCLUSION

From this finding it has been concluded that chronic administration of sesame oil offers cardio protective action via putative antioxidant property.

Cardioprotective effects of gallic acid in diabetes-induced myocardial dysfunction in rats

BACKGROUND

Normalization of hyperglycemia, hyperlipidemia, and oxidative stress is an important objective in preventing diabetes-induced cardiac dysfunction.

OBJECTIVE

This study was undertaken to examine the effects of gallic acid in myocardial dysfunctions associated with type-1 diabetes.

MATERIALS AND METHODS

Diabetes was induced by single intravenous injection of streptozotocin (STZ, 50 mg/kg i.v.). Gallic acid was administered daily at three different doses (100, 50, and 25 mg/kg p.o.) for 8 weeks at the end of which blood samples were collected and analyzed for various biochemical parameters.

RESULTS

Injection of STZ produced significant loss of body weight (BW), polyphagia, polydypsia, hyperglycemia, hypoinsulinemia, hyperlipidemia, hypertension, bradycardia, and myocardial functional alterations. Treatment with gallic acid significantly lowered fasting glucose, the AUC(glucose) level in a dose-dependent manner; however, the insulin level was not increased significantly at same the dose and prevented loss of BW, polyphagia, and polydypsia in diabetic rats. It also prevented STZ-induced hyperlipidemia, hypertension, bradycardia, structural alterations in cardiac tissue such as increase in force of contraction, left ventricular weight to body weight ratio, collagen content, protein content, serum lactate dehydrogenase, and creatinine kinase levels in a dose-dependent manner. Further, treatment also produced reduction in lipid peroxidation and increase in antioxidant parameters in heart of diabetic rats.

CONCLUSION

The results of this study suggest that gallic acid to be beneficial for the treatment of myocardial damage associated with type-1 diabetes.

Luteolin ameliorates cardiac failure in type I diabetic cardiomyopathy

OBJECTIVE

The study aimed to determine whether luteolin can confer cardioprotective effects against diabetic cardiomyopathy in relation to specific and quantitative markers of oxidative stress.

METHODS

We examined diabetic cardiomyopathy by left ventricular hemodynamic analysis. Myocardial oxidative stress was assessed by measuring the activity of superoxide dismutase (SOD) as well as the level of malondialdehyde (MDA). Hypolipidaemic effects of luteolin were also investigated in STZ-induced diabetic rats. Myocardial Akt/PKB phosphorylation, heme oxygenase-1 (HO-1) and connective tissue growth factor (CTGF) protein levels were measured by Western blot in all rats at the end of the study.

RESULTS

This study showed a significant increase in serum triacylglycerol (TG), total cholesterol (TC), lower density lipoprotein (LDL), MDA content, creatine kinase (CK), lactate dehydrogenase (LDH), and myocardial CTGF and a significant decrease in high density lipoprotein (HDL), SOD and Akt phosphorylation level in the diabetic group compared to the control group. Luteolin treatment induced a significant decrease in serum TG, TC, LDL, MDA, CK, LDH, and myocardial CTGF and a significant increase in HDL, SOD and Akt phosphorylation levels in comparison with the diabetic group.

CONCLUSION

These results show that luteolin protects against the progression of diabetes mellitus-induced cardiac dysfunction by attenuation of myocardial oxidative stress probably through its antioxidant properties.

Riboflavin alleviates cardiac failure in Type I diabetic cardiomyopathy

Heart failure (HF) is a common and serious comorbidity of diabetes. Oxidative stress has been associated with the pathogenesis of chronic diabetic complications including cardiomyopathy. The ability of antioxidants to inhibit injury has raised the possibility of new therapeutic treatment for diabetic heart diseases. Riboflavin constitutes an essential nutrient for humans and animals and it is an important food additive. Riboflavin, a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), enhances the oxidative folding and subsequent secretion of proteins. The objective of this study was to investigate the cardioprotective effect of riboflavin in diabetic rats. Diabetes was induced in 30 rats by a single injection of streptozotocin (STZ) (70 mg /kg). Riboflavin (20 mg/kg) was orally administered to animals immediately after induction of diabetes and was continued for eight weeks. Rats were examined for diabetic cardiomyopathy by left ventricular (LV) remadynamic function. Myocardial oxidative stress was assessed by measuring the activity of superoxide dismutase (SOD), the level of malondialdehyde (MDA) as well as heme oxygenase-1 (HO-1) protein level. Myocardial connective tissue growth factor (CTGF) level was measured by Western blot in all rats at the end of the study. In the untreated diabetic rats, left ventricular systolic pressure (LVSP) rate of pressure rose (+dp/dt), and rate of pressure decay (−dp/dt) were depressed while left ventricular end-diastolic pressure (LVEDP) was increased, which indicated the reduced left ventricular contractility and slowing of left ventricular relaxation. The level of SOD decreased, CTGF and HO-1 protein expression and MDA content rose. Riboflavin treatment significantly improved left ventricular systolic and diastolic function in diabetic rats, there were persistent increases in significant activation of SOD and the level of HO-1 protein, and a decrease in the level of CTGF. These results suggest that riboflavin treatment ameliorates myocardial function and improves heart oxidant status, whereas raising myocardial HO-1 and decreasing myocardial CTGF levels have beneficial effects on diabetic cardiomyopathy.

Antihyperhomocysteinemic and antihyperlipidemic effect of Trichilia connaroides in methionine-induced hyperhomocysteinemic animals

The current study investigates the antihyperhomocysteinemic and antihyperlipidemic effect of chloroform and methanol extracts of the leaves of Trichilia connaroides in methionine-induced hyperhomocysteinemic rats. Hyperhomocysteinemia was induced in albino Wistar rats by oral administration of L-Methionine (1 gm / kg) and they were treated simultaneously with chloroform and methanol extracts (100 mg / kg) from the leaves of Trichilia connaroides. Serum homocysteine, lipid profile, and products of lipid peroxidation (MDA) in the heart homogenate were recorded and treated for statistical significance. Hyperhomocysteinemic animals recorded significantly elevated serum homocysteine changes in lipid profile (P < 0.01) and Thibarbituric acid reactive substances (P < 0.01), compared to the vehicle control animals. Animals treated with chloroform and methanol extracts recorded significantly (P < 0.01) lower serum homocysteine, entire lipid profile, LPO (P < 0.01), except a significant increase in HDL-cholesterol (P < 0.01) compared to hyperhomocysteinemic animals. Thus, we conclude that chloroform and methanol extracts of Trichilia connaroides have significant antihyperhomocysteinemic and antihyperlipidemic effects on methionine–induced hyperhomocysteinemic animals. Trichilia connaroides, therefore, holds promise as a cardioprotective herb.

Telmisartan, a dual ARB/partial PPAR-γ agonist, protects myocardium from ischaemic reperfusion injury in experimental diabetes

AIM

Apart from its angiotensin receptor blocker (ARB) activity, telmisartan is also a partial agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ). Therefore, we assessed whether telmisartan treatment attenuates myocardial ischaemia/reperfusion (I/R) injury in diabetic rats through PPAR-γ pathway.

METHODS

Diabetic rats were randomized to receive vehicle (sham and I/R), telmisartan (10 mg/kg/day, orally), PPAR-γ antagonist GW9662 (1 mg/kg/day, intraperitoneally) or both for 14 days. On 15th day, excluding sham group, left anterior descending coronary artery occlusion was performed for 45 min followed by 1 h of reperfusion. Haemodynamic, biochemical, histopathological, ultrastructural, immunohistochemical (Bax and Bcl-2 protein), TUNEL positivity, infarct size and western blot studies were performed.

RESULTS

Telmisartan treatment significantly improved cardiac function by normalizing mean arterial pressure, left ventricular pressure (±LVdP/dt(max) , a marker of myocardial contraction and relaxation), by decreasing left ventricular end-diastolic pressure (a marker of preload, 3.7 ± 0.41 vs. 7.3 ± 0.89, p < 0.001) and percent infarct area (37.52 ± 5.83 vs. 46.27 ± 3.20, p < 0.01) as compared to diabetic I/R group. Interestingly, GW9662 worsens the I/R injury (percent infarct area, 54.38 ± 6.48 vs. 46.27 ± 3.20, p < 0.01), whereas telmisartan with GW9662 (percent infarct area, 41.16 ± 8.23 vs. 46.27 ± 3.20, p < 0.05) showed lesser significant results as compared to telmisartan alone. Additionally, telmisartan significantly ameliorates activities of endogenous antioxidants, creatine kinase-MB isoenzyme, lactate dehydrogenase and prevented the increase of tumour necrosis factor-alpha and malondialdehyde in myocardium. Furthermore, telmisartan also decreased Bax expression (4.45 ± 1.24% vs. 10.25 ± 0.96%, p < 0.01), number of TUNEL-positive cells (6.2 ± 0.98% vs. 13.0 ± 1.6, p < 0.01), inflammation, myonecrosis and increased Bcl-2 expression (5.45 ± 0.15% vs. 1.24 ± 0.3%, p < 0.01). On the other hand, GW9662 treatment alone increased the Bax expression, TUNEL positivity and decreased Bcl-2 expression. Telmisartan protective effects were partially attenuated by a co-administration with GW9662. Western blot analysis showed that telmisartan treatment enhanced PPAR-γ expression, whereas GW9662 decreased it in myocardium.

CONCLUSIONS

In addition to the class effect of ARBs, telmisartan has a beneficial effect in I/R injury in diabetic rats in part because of activation of PPAR-γ.

Ellagic acid ameliorates isoproterenol induced oxidative stress: Evidence from electrocardiological, biochemical and histological study

The present study was designed to evaluate the cardioprotective effects of ellagic acid against isoproterenol induced myocardial infarction in rats by studying electrocardiography, blood pressure, cardiac markers, lipid peroxidation, antioxidant defense system and histological changes. Male Wistar rats were treated orally with ellagic acid (7.5 and 15mg/kg) daily for a period of 10 days. After 10 days of pretreatment, isoproterenol (100mg/kg) was injected subcutaneously to rats at an interval of 24h for 2 days to induce myocardial infarction. Isoproterenol administered rats showed significant changes in the electrocardiogram pattern, arterial pressure, and heart rate. Isoproterenol-induced rats also showed significant (P<0.05) increase in the levels of serum troponin-I, creatine kinase, lactate dehydrogenase, C-reactive protein, plasma homocysteine, heart tissue thiobarbituric acid reactive substances and lipid hydro peroxides. The activities/levels of antioxidant system were decreased in isoproterenol-induced rats. The histopathological findings of the myocardial tissue evidenced myocardial damage in isoproterenol induced rats. The oral pretreatment of ellagic acid restored the pathological electrocardiographic patterns, regulated the arterial blood pressures and heart rate in the isoproterenol induced myocardial infarcted rats. The ellagic acid pretreatment significantly reduced the levels of biochemical markers, lipid peroxidation and significantly increased the activities/levels of the antioxidant system in the isoproterenol induced rats. An inhibited myocardial necrosis was evidenced by the histopathological findings in ellagic acid pretreated isoproterenol induced rats. Our study shows that oral pretreatment of ellagic acid prevents isoproterenol induced oxidative stress in myocardial infarction.

Cardioprotective effect of 'Khamira Abresham Hakim Arshad Wala' a unani formulation in isoproterenol-induced myocardial necrosis in rats

The present study was designed to investigate whether Khamira Abresham Hakim Arshad Wala (KAHAW), a preparation of Unani System of Medicine, is able to attenuate the isoproterenol (ISO)-induced myocardial necrosis on the basis of its effects on hemodynamic, antioxidant, histopathological and ultrastructural parameters. Male Wistar albino rats were administered KAHAW (200, 400 and 800mg/kg/day, orally) or vehicle for 14 days with concurrent ISO administration (85mg/kg, subcutaneously, 2 doses at 24h interval) on 13th and 14th day. On the 15th day, vehicle+ISO-treated rats exhibit cardiac dysfunctions as indicated by decrease in systolic, diastolic, and mean arterial pressures, reduction in both maximum positive and maximum negative rates of developed left ventricular pressure (+/-LVdp/dt) and an increase in left ventricular end-diastolic pressure (LVEDP). Biochemical analysis of their heart homogenate presented reduced levels of enzymes viz., superoxide dismutase (SOD), catalase (CAT), lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) isoenzyme. A marked reduction in reduced glutathione (GSH) levels along with increase in levels of thiobarbituric acid reactive substances (TBARS) was also observed in rat myocardium. Myocardial necrosis, edema and inflammation were evident from the light microscopic and ultrastructural changes. KAHAW at dose of 800mg/kg/day significantly reversed majority of hemodynamic and antioxidant derangements. The protective role of KAHAW on ISO-induced myocardial necrosis was further confirmed by histopathological and ultrastructural examination. There was no significant change in heart rate in all experimental groups. KAHAW per se groups showed no significant change when compared with vehicle control group. The study results thus demonstrated the cardioprotective potential of KAHAW against ISO-induced myocardial necrosis and associated oxidative stress.

Oxidative and nitrosative stress and apoptosis in the liver of rats fed on high methionine diet: protective effect of taurine

OBJECTIVE

There are few reports about the direct toxic effects of hyperhomocysteinemia on the liver. We investigated oxidative and nitrosative stresses and apoptotic and necrotic changes in the liver of rats fed a high-methionine (HM) diet (2%, w/w) for 6 mo. We also investigated whether taurine, an antioxidant amino acid, is protective against an HM-diet-induced toxicity in the liver.

METHODS

Lipid peroxide levels, nitrotyrosine formation, and non-enzymatic and enzymatic antioxidants were determined in livers of rats fed an HM diet. In addition, apoptosis-related proteins, proapoptotic Bax and antiapoptotic B-cell lymphoma-2 expressions, apoptotic cell count, histopathologic appearance in the liver, and alanine transaminase and aspartate transaminase activities in the serum were investigated.

RESULTS

Plasma homocysteine levels and serum alanine transaminase and aspartate transaminase activities were increased after the HM diet. This diet resulted in increases in lipid peroxide and nitrotyrosine levels and decreases in non-enzymatic and enzymatic antioxidants in liver homogenates in rats. Bax expression increased, B-cell lymphoma-2 expression decreased, and apoptotic cell number increased in livers of rats fed an HM diet. Inflammatory reactions, microvesicular steatosis, and hepatocyte degeneration were observed in the liver after the HM diet. Taurine (1.5%, w/v, in drinking water) administration and the HM diet for 6 mo was found to decrease serum alanine transaminase and aspartate transaminase activities, hepatic lipid peroxide levels, and nitrotyrosine formation without any change in serum homocysteine levels. Decreases in Bax expression, increases in B-cell lymphoma-2 expression, decreases in apoptotic cell number, and amelioration of histopathologic findings were observed in livers of rats fed with the taurine plus HM diet.

CONCLUSION

Our results indicate that taurine has protective effects on hyperhomocysteinemia-induced toxicity by decreasing oxidative and nitrosative stresses, apoptosis, and necrosis in the liver.

Further studies on antioxidant potential and protection of pancreatic beta-cells by Embelia ribes in experimental diabetes

This study was designed to examine the antioxidant defense by ethanolic extract of Embelia ribes on streptozotocin-(40 mg/kg, intravenously, single-injection) induced diabetes in Wistar rats. Forty days of oral feeding the extract (100 mg/kg and 200 mg/kg) to diabetic rats resulted in significant (P < .01) decrease in blood glucose, blood glycosylated haemoglobin, serum lactate dehydrogenase, creatine kinase, and increase in blood glutathione levels as compared to pathogenic diabetic rats. Further, the extract also significantly (P < .01) decreased the pancreatic thiobarbituric acid-reactive substances (TBARS) levels and significantly (P < .01) increased the superoxide dismutase, catalase, and glutathione levels as compared to above levels in pancreatic tissue of pathogenic diabetic rats. The islets were shrunken in diabetic rats in comparison to normal rats. In the drug-treated diabetic rats, there was expansion of islets. The results of test drug were comparable to gliclazide (25 mg/kg, daily), a standard antihyperglycemic agent. The study concludes that Embelia ribes enhances the antioxidant defense against reactive oxygen species produced under hyperglycemic condition and this protects β-cells against loss, and exhibit antidiabetic property.

Methionine-supplemented diet augments hepatotoxicity and prooxidant status in chronically ethanol-treated rats

The purpose of this study was to investigate whether high methionine (HM) diet may influence the development of ethanol-induced hepatotoxicity and prooxidant-antioxidant balance in the liver. Rats received drinking water containing ethanol (20% v/v) and/or methionine supplemented diet (2% w/w) for 75 days. Although prooxidant-antioxidant balance did not change in the liver of rats in HM group, ethanol treatment was observed to increase plasma transaminase activities, and malondialdehyde (MDA) and protein carbonyl (PC) levels, but not glutathione (GSH), vitamin E and vitamin C levels, and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione transferase (GST) activities in the liver of rats as compared to controls. However, ethanol plus HM diet caused further increases in plasma transaminase activities and hepatic MDA and PC levels. In addition, SOD, GSH-Px and GST activities were observed to decrease, but GSH, vitamin E and vitamin C levels remained unchanged in the liver as compared to ethanol, HM and control groups. Our results show that HM diet may augment hepatotoxicity and oxidative stress in the liver of chronically ethanol-treated rats.

Effects of folic acid and magnesium on the production of homocysteine-induced extracellular matrix metalloproteinase-2 in cultured rat vascular smooth muscle cells

BACKGROUND

Hyperhomocysteinemia is an independent risk factor of coronary artery disease, but some studies have shown that patients with hyperhomocysteinemia are not prone to atherosclerosis. The aim of this study was to test whether homocysteine increases the production of matrix metalloproteinase-2 (MMP-2) and if extracellular additional magnesium and folic acid alters MMP-2 secretion.

METHODS AND RESULTS

Gelatin zymography and western blotting were used to investigate the effects of different homocysteine levels (0-5,000 micromol/L) on MMP-2 production, and the effects of different folic acid concentrations (0-10 micromol/L) and magnesium concentrations (0-3.0 mmol/L) on homocysteine-induced MMP-2 in cultured rat vascular smooth muscle cells. Furthermore, the changes in MMP-2 were compared under various treatments for 24 h, 48 h and 72 h. Homocysteine (50-1,000 micromol/L) increased the production of MMP-2 significantly in a dose-dependent manner and at a high level (5,000 micromol/L) reduced the production of MMP-2. Increased production of MMP-2 induced by homocysteine was reduced by additional extracellular folic acid in a dose-dependent manner. Magnesium also reduced the increase of MMP-2 production induced by homocysteine. Production of MMP-2 under various treatments for 72 h increased more than during 24 or 48 h.

CONCLUSIONS

Homocysteine (50-1,000 micromol/L) significantly increased the production of MMP-2 in a dose-dependent manner. Added extracellular folic acid and magnesium decreased the homocysteine-induced MMP-2 secretion. These data suggest a beneficial effect of folic acid and magnesium on the pathogenesis of coronary artery disease.

Role of TNF-alpha in ethanol-induced hyperhomocysteinemia and murine alcoholic liver injury

We previously reported a link between ethanol-induced elevation of homocysteine, endoplasmic reticulum (ER) stress, and alcoholic liver injury in the murine model of intragastric ethanol feeding. We studied the role of TNFalpha in this setting by using TNFR1 knockout mice (C57 BL/6). There was a 7.4-fold increase of homocysteine in wild-type and a 6-fold increase in TNFR1 knockout mice with intragastric alcohol exposure for 4 weeks. Plasma TNFalpha increased in the wild-type (18.4 +/- 3.3 pg/mL vs. 8.4 +/- 1.3 pg/mL (control)) and in the knockouts (12.9 +/- 1.4 pg/mL vs. 7.2 +/- 1.6 pg/mL (control)). Similar extent of fatty liver was observed in both types. Increased ALT was observed in both groups. Necroinflammatory foci were increased significantly in ethanol-fed knockouts but not to the same extent as in the ethanol-fed wild type. Increase of hepatic apoptosis and reduction of S-adenosyl-L-methionine was detected in both types of animals fed ethanol. ER stress demonstrated by RT-PCR of mRNA of selective ER stress markers GRP78, CHOP, and SREBP1 was increased equivalently in both types of mice. Betaine administration decreased ER stress in conjunction with attenuation of the elevated plasma homocysteine in both types of animals. Betaine increased hepatic S-adenosyl-L-methionine by 28 fold in the knockouts and by 24-fold in wild type. In conclusion, TNFalpha makes a moderate contribution to the ALT elevation, necroinflammation, apoptosis, a small contribution to the fatty liver and no contribution to hyperhomocysteinemia and ER stress in intragastric alcohol fed mice.

Mild hyperhomocysteinemia induced by feeding rats diets rich in methionine or deficient in folate promotes early atherosclerotic inflammatory processes

High homocysteine levels in vitro promote the expression of inflammatory agents responsible for atherogenesis. We investigated the long-term effects of elevated plasma homocysteine on the expression of inflammatory molecules and attempted to elucidate their mechanisms. Male Sprague-Dawley rats (n = 36) were randomly divided into 3 groups, which received the control AIN-93G diet, the control diet plus 10 g/kg of L-methionine, or that diet without folate (0 m/kg) for 14 wk. Mild hyperhomocysteinemia was then induced in both experimental groups. The mildly hyperhomocysteinemic rats had markedly increased expression of intracellular adhesion molecule-1 (ICAM-1) in the aorta and elevated serum levels of monocyte chemoattractant protein-1 (MCP-1), compared to the control rats. The activation of nuclear factor kappaB and formation of nitrotyrosine in the aorta were greater in rats with mild hyperhomocysteinemia than in control rats. Serum levels of malonyldialdehyde (MDA) were higher in mildly hyperhomocysteinemic rats than in control rats. These results suggest that the oxidative stress resulting from elevated plasma homocysteine stimulates the activation of nuclear factor kappaB, and consequently increases the expression of the inflammatory factors in vivo. Such an effect may contribute to atherogenesis by enhancing the inflammatory response of the vascular endothelium.