Cardioprotective Effect Of H2S Research Articles

Hydrogen sulfide functions as a micro-modulator bound at the copper active site of Cu/Zn-SOD to regulate the catalytic activity of the enzyme

The present study examines whether there is a mechanism beyond the current concept of post-translational modifications to regulate the function of a protein. A small gas molecule, hydrogen sulfide (H2S), was found to bind at active-site copper of Cu/Zn-SOD using a series of methods including radiolabeled binding assay, X-ray absorption near-edge structure (XANES), and crystallography. Such an H2S binding enhanced the electrostatic forces to guide the negatively charged substrate superoxide radicals to the catalytic copper ion, changed the geometry and energy of the frontier molecular orbitals of the active site, and subsequently facilitated the transfer of an electron from the superoxide radical to the catalytic copper ion and the breakage of the copper-His61 bridge. The physiological relevance of such an H2S effect was also examined in both invitro and invivo models where the cardioprotective effects of H2S were dependent on Cu/Zn-SOD.

Cardioprotective effects of hydrogen sulfide in attenuating myocardial ischemia‑reperfusion injury (Review).

Ischemic heart disease is one of the major causes of cardiovascular‑related mortality worldwide. Myocardial ischemia can be attenuated by reperfusion that restores the blood supply. However, injuries occur during blood flow restoration that induce cardiac dysfunction, which is known as myocardial ischemia‑reperfusion injury(MIRI). Hydrogen sulfide(H2S), the third discovered endogenous gasotransmitter in mammals (after NO andCO), participates in various pathophysiological processes. Previous invitro and invivo research have revealed the protective role of H2S in the cardiovascular system that render it useful in the protection of the myocardium against MIRI. The cardioprotective effects of H2S in attenuating MIRI are summarized in the present review.

Basic Pharmacological Characterization of EV-34, a New H2S-Releasing Ibuprofen Derivative.

Background: Cardioprotective effects of H2S are being suggested by numerous studies. Furthermore, H2S plays a role in relaxation of vascular smooth muscle, protects against oxidative stress, and modulates inflammation. Long-term high-dose use of NSAIDs, such as ibuprofen, have been associated with enhanced cardiovascular risk. The goal of the present work is the synthesis and basic pharmacological characterization of a newly designed H2S-releasing ibuprofen derivative. Methods: Following the synthesis of EV-34, a new H2S-releasing derivative of ibuprofen, oxidative stability assays were performed (Fenton and porphyrin assays). Furthermore, stability of the molecule was studied in rat serum and liver lysates. H2S-releasing ability of the EC-34 was studied with a hydrogen sulfide sensor. MTT (3-(4,5-dimethylthiazol 2-yl)-2,5-(diphenyltetrazolium bromide)) assay was carried out to monitor the possible cytotoxic effect of the compound. Cyclooxygenase (COX) inhibitory property of EV-34 was also evaluated. Carrageenan assay was carried out to compare the anti-inflammatory effect of EV-34 to ibuprofen in rat paws. Results: The results revealed that the molecule is stable under oxidative condition of Fenton reaction. However, EV-34 undergoes biodegradation in rat serum and liver lysates. In cell culture medium H2S is being released from EV-34. No cytotoxic effect was observed at concentrations of 10, 100, 500 µM. The COX-1 and COX-2 inhibitory effects of the molecule are comparable to those of ibuprofen. Furthermore, based on the carrageenan assay, EV-34 exhibits the same anti-inflammatory effect to that of equimolar amount of ibuprofen (100 mg/bwkg). Conclusion: The results indicate that EV-34 is a safe H2S releasing ibuprofen derivative bearing anti-inflammatory properties.

Cardioprotective effect of H2S and glutathione synthesis modulation is mediated by inhibition mitochondrial permeability transition pore opening

Hydrogen sulfide (H2S) was recently classified as the third gaseous transmitter produces by two cytosolic cystathionine γ-lyase (CSE) and cystathionine β-synthase, and one mitochondrial enzyme – 3-mercaptopyruvate sulfurtransferase. It was clearly shown that H2S protects against cardiac ischemia/reperfusion (I/R) injury in a wide range of exogenously applied doses of H2S donors. Cell damage within I/R injury is caused by extensive reactive oxygen species (ROS) mainly produced by mitochondria. ROS fleshes are associated with massive opening of mitochondrial permeability transition (MPT) pores and contribute to deterioration of heart function. However, it may be prevented in case of pharmacological inhibition of MPT pores opening. Mixture of mitochondrial metabolites released through the opened MPT pores can be detected in situ as increased optical density of outflow solutions at a wavelength of 245-250 nm and was called mitochondrial factor (MF). One of the most powerful antioxidant agents that preserve redox status in tissues is tripeptide glutathione. It forms in two ATP-depended reactions and exists in two forms reduced and oxidized one. Glutathione and H2S have a common precursor – amino acid L-cysteine. In this study, we used Langendorff isolated rat heart model to investigate the effect of H2S and glutathione synthesis modulation on MPT pores opening in I/R injury. Rats were pretreated intraperitoneally with D,L-propargylglycine (11,3 mg/kg), an inhibitor of H2S-producing enzyme CSE, L-cysteine (121 mg/kg) and buthionine sulfoximine (BSO, 22,2 mg/kg) an inhibitor of first step of glutathione synthesis. Cardiac function, oxygen metabolism and MPT pores opening in situ were measured. We clearly showed that treatment with PAG and L-cysteine provided pharmacological precondition and exerted cardioprotective effect inhibiting MPT pores opening as greatly decreased MF release from isolated heart. Pretreatment with BSO abolished cardioprotective effect of PAG+L-cysteine combination. Absorbance spectra in L-cysteine pretreated group did not differ from the control. Thus, we demonstrate that PAG+L-cysteine induced cardioprotection mediated via inhibition of MPT pores opening.

The influence of hydrogen sulfide on the structural characteristics of leukocytes mitochondrial apparatus in patients with arterial hypertension

One of the leading causes of arterial hypertension (AH) is mitochondrial dysfunction (MD) – moreover, disorders in regulation of blood pressure occur on the background of progressive energy deficiency. At the same time, the cardioprotective effect of H2S has been proven. In particular, the inhibition of mitochondrial pore opening by hydrogen sulfide plays an important role, and H2S should affect the structural component of MD, namely, the ultrastructure of mitochondria. However, at present, the question of structural changes in the mitochondrial apparatus in patients with hypertension is extremely insufficiently studied. For the study of MD in healthy people and patients with pathology, almost the only objects (in the absence of surgical intervention) are blood cells, in particular leukocytes. Based on the above, the aim of the study was to investigate the effect of a hydrogen sulfide donor on the ultrastructure of the mitochondrial apparatus of leukocytes in patients with arterial hypertension. The effect of a hydrogen sulfide donor on some ultrastructural characteristics of the leukocyte mitochondrial apparatus in patients with hypertension was studied. The examination involved patients (men) with arterial hypertension aged 30-60 years, who were divided into 2 age groups: 30-40 and 40-60 years. Control groups (healthy men without signs of hypertension) were randomized by age. An electron microscopic and morphometric assessment of the structure of mitochondria revealed that under hypertension it undergoes significant changes that depend on the age of the patients. It has been established that the addition of a hydrogen sulfide donor (Full Spectrum Garlic phytopreparation (Swanson Health Products, USA) at a dose of 400 mg per day) to the traditional therapy of hypertension leads to positive changes in the mitochondrial ultrastructure of the studied cells aimed at increasing the energy capacity of the mitochondrial apparatus – the quantity reduction of structurally damaged mitochondria, and with an increase in the duration of treatment – the increase their total number in people of the younger age group (by 57.5%), and in the older age group – by 53.7%. Thus, the indicated effect of H2S significantly depends both on the age of the patients (young people respond more intensively) and on the duration of the hydrogen sulfide donor using (long-term use is accompanied by a more pronounced positive dynamics of changes).

Hydrogen Sulfide Attenuates Renin Angiotensin and Aldosterone Pathological Signaling to Preserve Kidney Function and Improve Exercise Tolerance in Heart Failure

Cardioprotective effects of H2S have been well documented. However, the lack of evidence supporting the benefits afforded by delayed H2S therapy warrants further investigation. Using a murine model of transverse aortic constriction-induced heart failure, this study showed that delayed H2S therapy protects multiple organsincluding the heart, kidney, and blood-vessel; reduces oxidative stress; attenuates renal sympathetic and renin-angiotensin-aldosterone system pathological activation; and ultimately improves exercise capacity.Thesefindings provide further insights into H2S-mediated cardiovascular protection and implicatethebenefitsof using H2S-based therapies clinically for the treatment of heart failure.

Hydrogen sulfide ameliorated L-NAME-induced hypertensive heart disease by the Akt/eNOS/NO pathway.

Reductions in hydrogen sulfide (H2S) production have been implicated in the pathogenesis of hypertension; however, no studies have examined the functional role of hydrogen sulfide in hypertensive heart disease. We hypothesized that the endogenous production of hydrogen sulfide would be reduced and exogenous hydrogen sulfide would ameliorate cardiac dysfunction in Nω-nitro- L-arginine methyl ester ( L-NAME)-induced hypertensive rats. Therefore, this study investigated the cardioprotective effects of hydrogen sulfide on L-NAME-induced hypertensive heart disease and explored potential mechanisms. The rats were randomly divided into five groups: Control, Control + sodium hydrosulfide (NaHS), L-NAME, L-NAME + NaHS, and L-NAME + NaHS + glibenclamide (Gli) groups. Systolic blood pressure was monitored each week. In Langendorff-isolated rat heart, cardiac function represented by ±LV dP/dtmax and left ventricular developing pressure was recorded after five weeks of treatment. Hematoxylin and Eosin and Masson's trichrome staining and myocardium ultrastructure under transmission electron microscopy were used to evaluate cardiac remodeling. The plasma nitric oxide and hydrogen sulfide concentrations, as well as nitric oxide synthases and cystathionine-γ-lyase activity in left ventricle tissue were determined. The protein expression of p-Akt, Akt, p-eNOS, and eNOS in left ventricle tissue was analyzed using Western blot. After five weeks of L-NAME treatment, there was a time-dependent hypertension, cardiac remodeling, and dysfunction accompanied by a decrease in eNOS phosphorylation, nitric oxide synthase activity, and nitric oxide concentration. Meanwhile, cystathionine-γ-lyase activity and hydrogen sulfide concentration were also decreased. NaHS treatment significantly increased plasma hydrogen sulfide concentration and subsequently promoted the Akt/eNOS/NO pathway which inhibited the development of hypertension and attenuated cardiac remodeling and dysfunction. The cardioprotective effects of NaHS were counteracted by Gli which inhibited the Akt/eNOS/NO pathway. This suggests that the effects of hydrogen sulfide were mediated by the activation of the KATP channels. In conclusion, hydrogen sulfide ameliorated L-NAME-induced hypertensive heart disease via the activation of the Akt/eNOS/NO pathway, which was mediated by KATP channels. Impact statement 1. We found that H2S ameliorated L-NAME-induced cardiac remodeling and dysfunction, and played a protective role in L-NAME-induced hypertensive heart disease, which the existing studies have not reported. 2. H2S activated the Akt/eNOS/NO pathway, thereby playing a cardioprotective role in L-NAME-induced hypertensive heart disease. 3. The cardioprotective effect of H2S was mediated by ATP-sensitive potassium channels.

ATP-sensitive K⁺ channels contribute to the protective effects of exogenous hydrogen sulfide against high glucose-induced injury in H9c2 cardiac cells.

Hyperglycemia, as well as diabetes mellitus, has been shown to impair ATP-sensitive K+ (KATP) channels in human vascular smooth muscle cells. Hydrogen sulfide (H2S) is also known to be an opener of KATP channels. We previously demonstrated the cardioprotective effects exerted by H2S against high-glucose (HG, 35 mM glucose)-induced injury in H9c2 cardiac cells. As such, we hypothesized that KATP channels play a role in the cardioprotective effects of H2S against HG-induced injury. In this study, to examine this hypothesis, H9c2 cardiac cells were treated with HG for 24 h to establish a model of HG-induced insults. Our findings revealed that treatment of the cells with HG markedly decreased the expression level of KATP channels. However, the decreased expression of KATP channels was reversed by the treatment of the cells with 400 µM sodium hydrogen sulfide (NaHS, a donor of H2S) for 30 min prior to exposure to HG. Additionally, the HG-induced cardiomyocyte injuries, including cytotoxicity, apoptosis, oxidative stress and mitochondrial damage, were ameliorated by treatment with NaHS or 100 µM diazoxide (a mitochondrial KATP channel opener) or 50 µM pinacidil (a non-selective KATP channel opener) for 30 min prior to exposure to HG, as indicated by an increase in cell viability, as well as a decrease in the number of apoptotic cells, the expression of cleaved caspase-3, the generation of reactive oxygen species (ROS) and the dissipation of mitochondrial membrane potential (MMP). Notably, treatment of the H9c2 cardiac cells with 100 µM 5-hydroxydecanoic acid (5-HD, a mitochondrial KATP channel blocker) or 1 mM glibenclamide (Gli, a non-selective KATP channel blocker) for 30 min prior to treatment with NaHS and exposure to HG significantly attenuated the above-mentioned cardioprotective effects exerted by NaHS. Notably, treatment of the cells with 500 µM N-acetyl‑L‑cysteine (NAC, a scavenger of ROS) for 60 min prior to exposure to HG markedly reduced the HG-induced inhibitory effect on the expression of KATP channels. Taken together, our results suggest that KATP channels play an important role in the cardioprotective effects of exogenous H2S against HG-induced injury. This study also provides novel data demonstraring that there is an antagonistic interaction between ROS and KATP channels in HG-exposed H9c2 cardiac cells.

Hydrogen Sulfide Mediates Cardioprotection Through Nrf2 Signaling

The recent emergence of hydrogen sulfide (H(2)S) as a potent cardioprotective signaling molecule necessitates the elucidation of its cytoprotective mechanisms. The present study evaluated potential mechanisms of H(2)S-mediated cardioprotection using an in vivo model of pharmacological preconditioning. H(2)S (100 microg/kg) or vehicle was administered to mice via an intravenous injection 24 hours before myocardial ischemia. Treated and untreated mice were then subjected to 45 minutes of myocardial ischemia followed by reperfusion for up to 24 hours, during which time the extent of myocardial infarction was evaluated, circulating troponin I levels were measured, and the degree of oxidative stress was evaluated. In separate studies, myocardial tissue was collected from treated and untreated mice during the early (30 minutes and 2 hours) and late (24 hours) preconditioning periods to evaluate potential cellular targets of H(2)S. Initial studies revealed that H(2)S provided profound protection against ischemic injury as evidenced by significant decreases in infarct size, circulating troponin I levels, and oxidative stress. During the early preconditioning period, H(2)S increased the nuclear localization of Nrf2, a transcription factor that regulates the gene expression of a number of antioxidants and increased the phosphorylation of protein kinase Cepsilon and STAT-3. During the late preconditioning period, H(2)S increased the expression of antioxidants (heme oxygenase-1 and thioredoxin 1), increased the expression of heat shock protein 90, heat shock protein 70, Bcl-2, Bcl-xL, and cyclooxygenase-2 and also inactivated the proapoptogen Bad. These results reveal that the cardioprotective effects of H(2)S are mediated in large part by a combination of antioxidant and antiapoptotic signaling.

Abstract 1599: Hydrogen Sulfide Mediates Myocardial Preconditioning via Upregulation of Antioxidant and Anti-Apoptotic Signaling Pathways

The emergence of hydrogen sulfide (H 2 S) as a potent cardioprotective mediator necessitates the elucidation of its cytoprotective mechanisms. Therefore, we evaluated potential mechanisms of H 2 S-mediated cardioprotection using an in vivo model of preconditioning (PC). The H 2 S donor, IK1001 (100 μg/kg), or vehicle was administered to mice via an intravenous injection 24 hours prior to left coronary artery occlusion and reperfusion. Mice were subjected to 45 min of myocardial ischemia followed by reperfusion for up to 24 hr, during which time the extent of myocardial infarction was evaluated, serum troponin-I levels were measured, and the degree of oxidative stress was assessed. In separate studies, mice were treated with IK1001 and myocardial tissue was collected during both the early (30 min and 2hr) and late (24 hr) PC periods to evaluate potential cellular targets of H 2 S. IK1001 provided profound protection against ischemic injury as evidenced by significant decreases in infarct size, serum troponin-I levels, and oxidative stress. Additional studies revealed that during the early PC period H 2 S increased the nuclear localization of Nrf-2, a transcription factor that regulates the gene expression of a number of antioxidants, and increased the nuclear localization of phosphorylated STAT-3. During the late PC period, H 2 S increased the expression of the antioxidants, Trx-1 and Trx-2, increased the expression of HSP90, HSP70, Bcl-2, and Bcl-xL and also inactivated the pro-apoptogen Bad. Our results reveal that the cardioprotective effects of H 2 S are mediated in large part by a combination of antioxidant and anti-apoptotic signaling.

A new gaseous molecule-recent progress of hydrogen sulfide in cardioprotection

Recent studies suggest that hydrogen sulfide (H2S), like nitric oxide ( NO ) and carbon monoxide ( CO ), is the third gaseous signal molecule. It can influence many signal transductive pathways. H2S also can open ATP-sensitive K+ (KATP) channels, reduce oxidative stress, decrease inflammation and preserve mitochondrial function. This review summarizes recent progress in the cardioprotective effect of H2S which can ameliorate ischemia-reperfusion injury in relevant with above mentioned protective mechanisms. Key words: hydrogen sulfide; ischemia-reperfusion injury; cardioprotection

Hydrogen sulfide preconditioning by garlic when it starts to smell

GARLIC (Allium sativum, Liliaceae/Alliaaceae) has long been used for medicinal and culinary purpose. Its first medicinal use was reported 400 years ago, and documented medicinal use can be found in a research finding of Louis Pasteur in the 1800s (8). Originally used as a digestive aid and as an antifungal, antibacterial, or antiviral compound (during the World Wars it achieved the nickname Russian penicillin), garlic was first reported to be a cardioprotective agent in the 1980s (13). Much of its cardioprotective abilities have been attributed toward its ability to function as an antioxidant (4). For example, garlic contains antioxidant vitamins A, C, and E as well as selenium, a key element for the synthesis of the antioxidant enzyme glutathione peroxidase (6). The study by Chuah, Moore, and Zhu (3) appears to be the first report where an alternative mechanism of cardioprotection is proposed. This report is based on the fact that garlic contains an organosulfur-containing compound, S-allylcysteine (12). Raw garlic contains alk(en)yl cysteine sulfoxides and -glutamyl alk(en)yl cysteines, which upon activation, is converted into S-allylcysteine (deoxyallin) because of the deactivation of the enzyme allinase. Allicin is then formed from S-allyl-L-cysteine according to following scheme: