Is there any cardioprotective role of Taurine during cold ischemic period following global myocardial ischemia?

Taurine and enzymatically modified isoquercitrin protected against methotrexate-induced deteriorations in the conductivity and rhythmicity of the heart in rats: Antioxidant, anti-inflammatory, and histological architecture approach

Cardiotoxicity is one of the most devastating complications of cancer treatment by methotrexate (MTX). The present study aimed to investigate the potential anti-cardiotoxic efficacy of taurine (Tau) and enzymatically modified isoquercitrin (EMIQ) alone or combined against MTX-induced cardiotoxicity in adult male rats. A total of 36 rats were randomly divided into six groups (six animals each): control, MTX (a single i.p. dose of 20 mg/kg), EMIQ + MTX (26 mg/kg of EMIQ, p.o. for 16 days), Tau + MTX (500 mg/kg of Tau, p.o. for 16 days), EMIQ + Tau + MTX at the same previous doses, and (EMIQ + Tau)½ + MTX. MTX reduced the percentage of body weight change, the expression of dihydrofolate reductase (DHFR) and folypolyglutamyl synthetase (FPGS), the cleaved tumor necrosis factor alpha (TNF-α) level in the cardiac tissue, and the elevated serum TNF-α level. MTX extensively deteriorated the electrocardiography (ECG), inducing tachycardia with shortening of the time intervals between successive heartbeats (R-R interval), associated with elongation of ventricular depolarization (QRS interval), and the corrected total time for ventricular de- and repolarization (QTc) duration. Treatment with MTX resulted in a significant reduction in atrial depolarization (P amplitude) and rapid repolarization (T amplitude) and a significant elevation in plateau phase (ST height). MTX treatment resulted in swelling of cardiomyocytes with extensive vacuolization of sarcoplasm with numerous variably sized vacuoles in addition to apoptotic cells. Tau and EMIQ protected against MTX-induced deteriorations in the conductivity and rhythmicity of the heart through antioxidative, anti-inflammatory, and antiapoptotic activities. Treatment with tau and EMIQ combined at high or low doses offered superior protection to the heart than using each agent alone.

Taurine as Antioxidant in a Novel Cell- and Oxygen Carrier-Free Perfusate for Normothermic Machine Perfusion of Porcine Kidneys

Donor organ-shortage has resulted in the increased use of marginal grafts; however, normothermic machine perfusion (NMP) holds the potential for organ viability assessment and restoration of marginal grafts prior to transplantation. Additionally, cell-, oxygen carrier-free and antioxidants-supplemented solutions could potentially prevent adverse effects (transfusion reactions, inflammation, hemolysis), associated with the use of autologous packed red blood cell (pRBC)-based perfusates. This study compared 6 h NMP of porcine kidneys, using an established pRBC-based perfusate (pRBC, n = 7), with the novel cell- and oxygen carrier-free organ preservation solution Ecosol, containing taurine (Ecosol, n = 7). Despite the enhanced tissue edema and tubular injury in the Ecosol group, related to a suboptimal molecular mass of polyethylene glycol as colloid present in the solution, functional parameters (renal blood flow, intrarenal resistance, urinary flow, pH) and oxygenation (arterial pO₂, absence of hypoxia-inducible factor 1-alpha) were similar to the pRBC group. Furthermore, taurine significantly improved the antioxidant capacity in the Ecosol group, reflected in decreased lactate dehydrogenase, urine protein and tubular vacuolization compared to pRBC. This study demonstrates the feasibility of 6 h NMP using a taurine containing, cell- and oxygen carrier-free perfusate, achieving a comparable organ quality to pRBC perfused porcine kidneys.

The allelopathy and underlying mechanism of Skeletonema costatum on Karenia mikimotoi integrating transcriptomics profiling

The roles of allelopathy for succession of marine phytoplankton communities remain controversial, especially for the development of blooms. Physiological parameters measurement (Fv/Fm value, MDA content, SOD activity, Na⁺/K⁺, Ca²⁺/ Mg²⁺-ATPase activity, cell size, chlorophyll content, apoptosis and cell cycle) and whole transcriptome profiling analysis were used to investigate allelopathy effect of Skeletonema costatum on Karenia mikimotoi. Filtrate and extracts from S. costatum culture inhibited the growth of K. mikimotoi. Allelopathic effects were dose-dependent for filtrate culture and extract culture. K. mikimotoi scavenged excessive ROS and adapted to the stress fastly and easily, so oxidative damage was not the main cause of the growth inhibition. Allelochemicals of S. costatum were found to influence the structure and function of cell membrane of K. mikimotoi by damaging membrane structure till to cell necrosis, which caused high mortality. Coupled with the sensitivity of algal cells to environmental stress and restricted cell cycle, allelopathy was suggested to be deeply detrimental to the development of competition algal population.

Protective role of taurine against oxidative stress (Review)

Taurine is a fundamental mediator of homeostasis that exerts multiple roles to confer protection against oxidant stress. The development of hypertension, muscle/neuro‑​associated disorders, hepatic cirrhosis, cardiac dysfunction and ischemia/reperfusion are examples of some injuries that are linked with oxidative stress. The present review gives a comprehensive description of all the underlying mechanisms of taurine, with the aim to explain its anti‑oxidant actions. Taurine is regarded as a cytoprotective molecule due to its ability to sustain normal electron transport chain, maintain glutathione stores, upregulate anti‑oxidant responses, increase membrane stability, eliminate inflammation and prevent calcium accumulation. In parallel, the synergistic effect of taurine with other potential therapeutic modalities in multiple disorders are highlighted. Apart from the results derived from research findings, the current review bridges the gap between bench and bedside, providing mechanistic insights into the biological activity of taurine that supports its potential therapeutic efficacy in clinic. In the future, further clinical studies are required to support the ameliorative effect of taurine against oxidative stress.

Cardioprotective Effect of Ethanolic Leaf Extract of Melissa Officinalis L Against Regional Ischemia-Induced Arrhythmia and Heart Injury after Five Days of Reperfusion in Rats

Melissa officinalis has antioxidant and anti-inflammatory activities and is used in various diseases. Aim of the study: We investigated the role of M. officinalis extract (MOE) against ischemia-induced arrhythmia and heart injury after five days of reperfusion in an in-vivo rat model of regional heart ischemia. The leaf extract of M. officinalis was standardized through HPLC analysis. Adult male Sprague-Dawley rats (n = 32) were subjected to 30 min of ischemia by occlusion of the left anterior descending coronary artery followed by 5 days of reperfusion. The rats (n = 8 in each group) were randomized to receive vehicle or M. officinalis as follows: group I served as saline control with ischemia, groups II, III and IV received different doses of MOE- (25, 50 and 100 mg/kg, respectively), by oral gavage daily for 14 days prior to ischemia. Administration of M. officinalis significantly improved ischemia/reperfusion (I/R)-induced myocardial dysfunction by reduction of infarct size, also, during the ischemic period, ventricular tachycardia, and ventricular ectopic beats episodes decreased as compared with that of the control group. Stabilized ST segment changes and QTc shortening increased the R and T wave amplitudes and the heart rate during ischemia. The extract also caused significant elevations in serum superoxide dismutase (SOD) activity as well as a significant decrease in serum cardiac troponin I (CTnI), lactate dehydrogenase (LDH), and malondialdehyde (MDA) levels, 5 days after reperfusion. MOE-100mg/kg was the effective dose. Cinamic acid (21.81 ± 1.26 mg/gr) was the main phenolic compound of plant sample. The ethanol extract of M. officinalis was observed to exhibit cardioprotective effects against I/R injury, probably due to antioxidant properties. The results indicate that MOE has antioxidant and cardio-protective effects against ischemia-induced arrhythmias and ischemia-reperfusion induced injury as was reflected by reduction of infarct size and cardiac injury biomarkers. These data support the potential uses of M. officinalis in the treatment of heart ischemia- reperfusion disorders and even developing new anti- arrhythmias drugs after further investigations.

Effects and Mechanisms of Taurine as a Therapeutic Agent

Taurine is an abundant, β-amino acid with diverse cytoprotective activity. In some species, taurine is an essential nutrient but in man it is considered a semi-essential nutrient, although cells lacking taurine show major pathology. These findings have spurred interest in the potential use of taurine as a therapeutic agent. The discovery that taurine is an effective therapy against congestive heart failure led to the study of taurine as a therapeutic agent against other disease conditions. Today, taurine has been approved for the treatment of congestive heart failure in Japan and shows promise in the treatment of several other diseases. The present review summarizes studies supporting a role of taurine in the treatment of diseases of muscle, the central nervous system, and the cardiovascular system. In addition, taurine is extremely effective in the treatment of the mitochondrial disease, mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and offers a new approach for the treatment of metabolic diseases, such as diabetes, and inflammatory diseases, such as arthritis. The review also addresses the functions of taurine (regulation of antioxidation, energy metabolism, gene expression, ER stress, neuromodulation, quality control and calcium homeostasis) underlying these therapeutic actions.

UPLC‑QTOFMS‑based metabolomic analysis of the serum of hypoxic preconditioning mice

Hypoxic preconditioning (HPC) is well‑known to exert a protective effect against hypoxic injury; however, the underlying molecular mechanism remains unclear. The present study utilized a serum metabolomics approach to detect the alterations associated with HPC. In the present study, an animal model of HPC was established by exposing adult BALB/c mice to acute repetitive hypoxia four times. The serum samples were collected by orbital blood sampling. Metabolite profiling was performed using ultra‑performance liquid chromatography‑quadrupole time‑of‑flight mass spectrometry (UPLC‑QTOFMS), in conjunction with univariate and multivariate statistical analyses. The results of the present study confirmed that the HPC mouse model was established and refined, suggesting significant differences between the control and HPC groups at the molecular levels. HPC caused significant metabolic alterations, as represented by the significant upregulation of valine, methionine, tyrosine, isoleucine, phenylalanine, lysophosphatidylcholine (LysoPC; 16:1), LysoPC (22:6), linoelaidylcarnitine, palmitoylcarnitine, octadecenoylcarnitine, taurine, arachidonic acid, linoleic acid, oleic acid and palmitic acid, and the downregulation of acetylcarnitine, malate, citrate and succinate. Using MetaboAnalyst 3.0, a number of key metabolic pathways were observed to be acutely perturbed, including valine, leucine and isoleucine biosynthesis, in addition to taurine, hypotaurine, phenylalanine, linoleic acid and arachidonic acid metabolism. The results of the present study provided novel insights into the mechanisms involved in the acclimatization of organisms to hypoxia, and demonstrated the protective mechanism of HPC.

Improvement of kidney redox states contributes to the beneficial effects of dietary pomegranate peel against barium chloride-induced nephrotoxicity in adult rats

CONTEXT

Pomegranate (Punica granatum L., Punicaceae) is known to possess enormous antioxidant activity.

OBJECTIVE

This study investigates the protective effects of pomegranate peel against barium-mediated renal damage.

MATERIALS AND METHODS

Rats were exposed during 21 days either to barium (67 ppm), barium + pomegranate peel (5% of diet) or to only pomegranate peel (5% of diet).

RESULTS

Exposure rats to barium provoked a significant increase in kidney malondialdehyde (MDA), advanced oxidation protein products (AOPP) and hydrogen peroxide (H2O2) levels. Creatinine, urea and uric acid levels in plasma and urine were also modified. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, non protein thiol (NPSH) and reduced glutathione (GSH) levels were decreased. Metallothionein (MT) production was increased and their genes expressions were up-regulated. All these changes were improved by dietary pomegranate peel. Moreover, the distorted histoarchitecture in kidney of barium group was alleviated by pomegranate peel.

CONCLUSION

Our data showed, for the first time, the protective effects of pomegranate peel against barium-induced renal oxidative damage.

Strategies for Pharmacological Organoprotection during Extracorporeal Circulation Targeting Ischemia-Reperfusion Injury

Surgical correction of congenital cardiac malformations or aortocoronary bypass surgery in many cases implies the use of cardiopulmonary-bypass (CPB). However, a possible negative impact of CPB on internal organs such as brain, kidney, lung and liver cannot be neglected. In general, CPB initiates a systemic inflammatory response (SIRS) which is presumably caused by contact of blood components with the surface of CPB tubing. Moreover, during CPB the heart typically undergoes a period of cold ischemia, and the other peripheral organs a global low flow hypoperfusion. As a result, a plethora of pro-inflammatory mediators and cytokines is released activating different biochemical pathways, which finally may result in the occurrence of microthrombosis, microemboli, in depletion of coagulation factors and haemorrhagic diathesis besides typical ischemia-reperfusion injuries. In our review we will focus on possible pharmacological interventions in patients to decrease negative effects of CPB and to improve post-operative outcome with regard to heart and other organs like brain, kidney, or lung.

Cardiorenal protective effect of taurine against cyclophosphamide-induced toxicity in albino rats

Cyclophosphamide (CP) is a cytotoxic alkylating agent used in the treatment of malignant diseases and autoimmune disorders. Its clinical use is limited to its marked cardiorenal toxicity. The present study aimed to investigate the possible protective role of taurine (Tau; 200 mg·kg^-1 per day, i.p.) on CP-induced cardiorenal toxicity. CP (200 mg·kg^-1) was administered as a single intraperitoneal injection whereas; Tau was administered for 3 weeks on a daily basis. The results showed that CP produced an elevation in serum activities of creatine kinase, creatine kinase isoenzyme, lactate dehydrogenase, creatinine as well as blood urea nitrogen. CP also induced an elevation in the oxidative stress markers viz. elevation in the serum lipid peroxides level (measured as malondialdehyde; MDA) and reduction in reduced glutathione level and superoxide dismutase activity in both heart and renal tissue. On the other hand, administration of Tau attenuated the CP-evoked disturbances in the above mentioned parameters. In addition, CP exhibited electrocardiographic (ECG) changes, which were significantly reversed by Tau treatment. Finally, the histopathological examination emphasized the obtained results. In conclusion, Tau is suggested to be a potential candidate to ameliorate CP-induced cardiorenal toxicity that may be related to its antioxidant activity.

Vasopressin attenuates ischemia-reperfusion injury via reduction of oxidative stress and inhibition of mitochondrial permeability transition pore opening in rat hearts

Aim of this study was to investigate the involvement of the mitochondrial permeability transition pore (MPTP) and oxidative stress in the cardioprotective effect of vasopressin (AVP) on ischemia/reperfusion (I/R) injury. Anesthetized male wistar rats were subjected to regional 30 min ischemia and 120 min reperfusion and randomly divided into nine groups: (1) Control; saline was administered intravenously before ischemia, (2) vasopressin was administrated 10 min prior to ischemia, (3, 4) Atractyloside as MPTP opener, was injected 5 min prior to reperfusion without and with vasopressin, (5, 6) Cyclosporine A as a MPTP closer, was injected 5 min prior to reperfusion without and with vasopressin, (7) mitochondria were isolated from control group and CaCl2 was added as MPTP opener and swelling inducer, (8) isolated mitochondria from Control hearts was incubated with Cyclosporine A before adding the CaCl2 (9) CaCl2 was added to isolated mitochondria from vasopressin group. Infusion of vasopressin decreased infarct size (18.6±1.7% vs. control group 37.6±2.4%), biochemical parameters [LDH (Lactate Dehydrogenase), CK-MB (Creatine Kinase-MB) and MDA (Malondialdehyde) plasma levels, PAB (Prooxidant-antioxidant balance)] compared to control group. Atactyloside suppressed the cardioprotective effect of vasopressin (32.5±1.9% vs. 18.6±1.7%) but administration of the Cyclosporine A without and with vasopressin significantly reduced infarct size to 17.7±4% (P<0.001) and 22.7±3% (P<0.01) respectively, vs. 37.6±2.4% in control group. Also, vasopressin, similar to Cyclosporine A, led to decrease in CaCl2-induced swelling. It seems that vasopressin through antioxidant effect and MPTP inhibition has created a cardioprotection against ischemia/reperfusion injuries.

Physiological role of taurine--from organism to organelle

Taurine is often referred to as a semi-essential amino acid as newborn mammals have a limited ability to synthesize taurine and have to rely on dietary supply. Taurine is not thought to be incorporated into proteins as no aminoacyl tRNA synthetase has yet been identified and is not oxidized in mammalian cells. However, taurine contributes significantly to the cellular pool of organic osmolytes and has accordingly been acknowledged for its role in cell volume restoration following osmotic perturbation. This review describes taurine homeostasis in cells and organelles with emphasis on taurine biophysics/membrane dynamics, regulation of transport proteins involved in active taurine uptake and passive taurine release as well as physiological processes, for example, development, lung function, mitochondrial function, antioxidative defence and apoptosis which seem to be affected by a shift in the expression of the taurine transporters and/or the cellular taurine content.

The Effect of Perinatal Taurine on Adult Renal Function Does Not Appear to Be Mediated by Taurine's Inhibition of the Renin-Angiotensin System

This study tests the hypothesis that perinatal taurine supplementation alters adult renal function by inhibition of the renin-angiotensin system. Female Sprague-Dawley rats were fed normal rat chow and given water alone (Control) or water containing an angiotensin converting enzyme inhibitor (captopril, 400 mg/ml) from conception until delivery (FD) or from delivery until weaning (LD). After weaning, the rats received normal rat chow and tap water. At 7–8 weeks of age, renal function at rest and after acute saline load was studied in conscious, restrained male rats. Body weight, mean arterial pressure, heart rate, effective renal blood flow, and renal vascular resistance were not significantly different among the three groups. Compared to Control, glomerular filtration rate, but not filtration fraction, significantly increased after saline load in both FD and LD groups. Water excretion significantly increased only in FD compared to Control, while fractional water excretion was significantly increased after saline load in both FD and LD groups. Sodium excretion significantly increased after saline load only in FD, while both captopril-treated groups significantly decreased fractional sodium excretion. Potassium excretion significantly increased in both FD and LD groups, while fractional potassium excretion significantly increased at rest in FD and decreased in LD groups after saline load. These effects of perinatal RAS inhibition on adult renal function contrast sharply, and are opposite in many cases to, the effects of perinatal taurine supplementation. Thus, these data suggest that perinatal taurine supplementation does not alter adult renal function through its ability to inhibit the perinatal RAS.

Effects of glycyl-glutamine dipeptide supplementation on myocardial damage and cardiac function in rats after severe burn injury

Glutamine decreases myocardial damage in ischemia/reperfusion injury. However, the cardioprotective effect of glutamine after burn injury remains unclear. Present study was to explore the protective effect of glycyl-glutamine dipeptide on myocardial damage in severe burn rats. Seventy-two Wistar rats were randomly divided into three groups: normal control (C), burned control (B) and glycyl-glutamine dipeptide-treated (GG) groups. B and GG groups were inflicted with 30% total body surface area of full thickness burn. The GG group was given 1.5 g/kg glycyl-glutamine dipeptide per day and the B group was given the same dose of alanine via intraperitoneal injection for 3 days. The serum CK, LDH, AST, and, blood lactic acid levels, as well as the myocardium ATP and GSH contents, were measured. The indices of cardiac contractile function and histopathological change were analyzed at 12, 24, 48, and 72 post-burn hours (PBH). The serum CK, LDH, AST and blood lactic acid levels increased, and the myocardium ATP and GSH content decreased in both burned groups. Compared with B group, the CK, LDH, AST and blood lactic acid levels reduced, myocardium ATP and GSH content increased in GG group. Moreover, the inhibition of cardiac contractile function and myocardial histopathological damage were reduced significantly in GG group. We conclude that myocardial histological structure and function were damaged significantly after burn injury, glycyl-glutamine dipeptide supplementation is beneficial to myocardial preservation by improving cardiocyte energy metabolism, increasing ATP and glutathione synthesis.

Volume-sensitive release of organic osmolytes in the human lung epithelial cell line A549: role of the 5-lipoxygenase

Pathophysiological conditions challenge cell volume homeostasis and perturb cell volume regulatory mechanisms leading to alterations of cell metabolism, active transepithelial transport, cell migration, and death. We report that inhibition of the 5-lipoxygenase (5-LO) with AA861 or ETH 615-139, the cysteinyl leukotriene 1 receptor (CysLT₁) with the antiasthmatic drug Zafirlukast, or the volume-sensitive organic anion channel (VSOAC) with DIDS blocks the release of organic osmolytes (taurine, meAIB) and the concomitant cell volume restoration following hypoosmotic swelling of human type II-like lung epithelial cells (A549). Reactive oxygen species (ROS) are produced in A549 cells upon hypotonic cell swelling by a diphenylene iodonium-sensitive NADPH oxidase. The swelling-induced taurine release is suppressed by ROS scavenging (butylated hydroxytoluene, N-acetyl cysteine) and potentiated by H₂O₂. Ca²⁺ mobilization with ionomycin or ATP stimulates the swelling-induced taurine release whereas calmodulin inhibition (W7) inhibits the release. Chelation of the extracellular Ca²⁺ (EGTA) had no effect on swelling-induced taurine release but prevented ATP-induced stimulation. H₂O₂, ATP, and ionomycin were unable to stimulate the taurine release in the presence of AA861 or Zafirlukast, placing 5-LO and CysLT₁ as essential elements in the swelling-induced activation of VSOAC with ROS and Ca²⁺ as potent modulators. Inhibition of tyrosine kinases (genistein, cucurbitacin) reduces volume-sensitive taurine release, adding tyrosine kinases (Janus kinase) as regulators of VSOAC activity. Caspase-3 activity during hypoxia is unaffected by inhibition of 5-LO/CysLT₁ but reduced when swelling-induced taurine loss via VSOAC is prevented by DIDS excess extracellular taurine, indicating a beneficial role of taurine under hypoxia.

Low-dose taurine upregulates taurine transporter expression in acute myocardial ischemia

Taurine exerts a protective effect on cardiomyocytes. The aim of this study was to determine whether the protective effect of taurine is associated with the upregulation of taurine transporter (TAUT) expression in acute myocardial ischemia (AMI). To this end, we investigated TAUT expression in cultured cardiomyocytes exposed to hypoxia as well as in rats with AMI treated with or not with taurine. The morphology of cardiac tissues, the apoptosis of cardiomyocytes and cardiac function were examined. In addition, the taurine content and the expression of TAUT were measured. Our data demonstrated that taurine reversed the apoptosis induced by hypoxia and AMI, thereby, effectively protecting the myocardium. Taurine content and TAUT expression levels were significantly decreased when cardiomyocytes and cardiac tissues were subjected to hypoxic or ischemic stress, while the expression of cysteine sulfinate decarboxylase was unchanged. Moreover, treatment with taurine (100 mg/kg/day) significantly upregulated TAUT expression and elevated the taurine content in ischemic myocardial tissues. In vitro, the low-dose (40 mM) but not the high-dose (120 mM) administration of taurine significantly induced TAUT expression and elevated the intracellular taurine content in hypoxic cardiomyocytes. In conclusion, our data demonstrate that taurine exerts a protective effect on the ischemic myocardium. Low-dose but not high-dose taurine treatment upregulated TAUT expression and increased the intracellular taurine content in cardiomyocytes subjected to hypoxia as well as in AMI tissues.

Effects of taurine on myocardial cGMP/cAMP ratio, antioxidant ability, and ultrastructure in cardiac hypertrophy rats induced by isoproterenol

Taurine is the most abundant free amino acid in the human body and accounts for more than 50% of the total amino acid pool in the mammalian heart. To investigate the preventive effects of taurine on cardiac hypertrophy in rats, myocardial injury was established by hypodermic injection of isoprenaline (ISO) (10 mg/kg d) for 7 days. The preventive effects of taurine (100 mg/kg d, 200 mg/kg d, and 300 mg/kg d, i.p) on heart coefficient; ultrastructure of cardiac muscle; the levels of creatine kinase heart isoenzyme (CK-MB), cAMP, and cGMP; and antioxidant ability were investigated. The results showed that taurine could significantly prevent the increase of heart coefficient induced by ISO. Compared with the model group, 100 mg/kg and 200 mg/kg taurine significantly decrease the levels of cAMP and cGMP, while 300 mg/kg taurine could significantly decrease the levels of cAMP in myocardium, and all the three concentrations of taurine could significantly increase the ratio of cGMP/cAMP. The level of serum CK-MB was significantly increased by ISO; 200 mg/kg taurine could significantly decrease it, but 100 mg/kg and 300 mg/kg taurine had no significant effect. As for the antioxidant ability, ISO administration could significantly increase the myocardial level of MDA but had no significant effects on the myocardial levels of SOD, GSH, GSH-Px, and T-AOC. However, taurine administration could significantly decrease the myocardial level of MDA and increase the levels of GSH and T-AOC compared with the model group. The serum levels of SOD, GSH-Px, GSH, and T-AOC were significantly reduced by ISO administration, but the level of MDA showed no significant changes compared with the control group. Taurine administration could significantly increase the serum levels of SOD, GSH-Px, GSH, and T-AOC and decrease the level of MDA compared with the model group. All the results indicated that 200 mg/kg taurine had better effects. The ultrastructure of cardiomyocytes showed that taurine administration could significantly reverse the injury caused by ISO. In conclusion, the present study demonstrated that taurine could inhibit the injury induced by ISO by increasing myocardial negative inotropic effect and antioxidant ability, decreasing the hypertrophic response to isoproterenol and protecting the integrity of -myocardial ultrastructure, decreasing myocardial leak of CK-MB.

Perinatal taurine exposure affects adult arterial pressure control

Taurine is an abundant, free amino acid found in mammalian cells that contributes to many physiologic functions from that of a simple cell osmolyte to a programmer of adult health and disease. Taurine's contribution extends from conception throughout life, but its most critical exposure period is during perinatal life. In adults, taurine supplementation prevents or alleviates cardiovascular disease and related complications. In contrast, low taurine consumption coincides with increased risk of cardiovascular disease, obesity and type II diabetes. This review focuses on the effects that altered perinatal taurine exposure has on long-term mechanisms that control adult arterial blood pressure and could thereby contribute to arterial hypertension through its ability to program these cardiovascular regulatory mechanisms very early in life. The modifications of these mechanisms can last a lifetime and transfer to the next generation, suggesting that epigenetic mechanisms underlie the changes. The ability of perinatal taurine exposure to influence arterial pressure control mechanisms and hypertension in adult life appears to involve the regulation of growth and development, the central and autonomic nervous system, the renin-angiotensin system, glucose-insulin interaction and changes to heart, blood vessels and kidney function.

Effects of glutamine treatment on myocardial damage and cardiac function in rats after severe burn injury

Treatment with glutamine has been shown to reduce myocardial damage associated with ischemia/reperfusion injury. However, the cardioprotective effect of glutamine specifically after burn injury remains unclear. The present study explores the ability of glutamine to protect against myocardial damage in rats that have been severely burned. Seventy-two Wistar rats were randomly divided into three groups: normal controls (C), burned controls (B) and a glutamine-treated group (G). Groups B and G were subjected to full thickness burns comprising 30% of total body surface area. Group G was administered 1.5 g/ (kg•d) glutamine and group B was given the same dose of alanine via intragastric administration for 3 days. Levels of serum creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST) and blood lactic acid were measured, as well as myocardial ATP and glutathione (GSH) contents. Cardiac function indices and histopathological changes were analyzed at 12, 24, 48 and 72 post-burn hours. In both burned groups, levels of serum CK, LDH, AST and blood lactic acid increased significantly, while myocardial ATP and GSH contents decreased. Compared with group B, CK, LDH, and AST levels were lower and blood lactic acid, myocardial ATP and GSH levels were higher in group G. Moreover, cardiac contractile function inhibition and myocardial histopathological damage were significantly reduced in group G compared to B. Taken together, these results show that glutamine supplementation protects myocardial structure and function after burn injury by improving energy metabolism and by promoted the synthesis of ATP and GSH in cardiac myocytes.

The cardioprotective effect of different doses of vasopressin (AVP) against ischemia-reperfusion injuries in the anesthetized rat heart

The aim of the present study was to investigate the protective effect of various doses of exogenous vasopressin (AVP) against ischemia-reperfusion injury in anesthetized rat heart. Anesthetized rats were randomly divided into seven groups (n=4-13) and all of them subjected to prolonged 30 min regional ischemia and 120 min reperfusion. Group I served as saline control with ischemia, in treatment groups II, III, IV and V, respectively different doses of AVP (0.015, 0.03, 0.06 and 1.2 μg/rat) were infused within 10 min prior to ischemia, in group VI, an AVP-selective V1 receptor antagonist (SR49059, 1mg/kg, i.v.) was administrated prior to effective dose of AVP injection and in group VII, SR49059 (1 mg/kg, i.v.) was only administrated prior to ischemia. Various doses of AVP significantly prevented the decrease in heart rate (HR) at the end of reperfusion compared to their baseline and decreased infarct size, biochemical parameters [LDH (lactate dehydrogenase), CK-MB (creatine kinase-MB) and MDA (malondialdehyde) plasma levels], severity and incidence of ventricular arrhythmia, episodes and duration of ventricular tachycardia (VT) as compared to control group. Blockade of V1 receptors by SR49059 attenuated the cardioprotective effect of AVP on ventricular arrhythmias and biochemical parameters, but partially returned infarct size to control. AVP 0.03 μg/rat was known as effective dose. Our results showed that AVP owns a cardioprotective effect probably via V1 receptors on cardiac myocyte against ischemia/reperfusion injury in rat heart in vivo.