Nitric Oxide System Research Articles

The effect of intense physical exertion on the biochemical parameters of antioxidant protection systems and nitric oxide in swimming athletes

Introduction. Intense physical activity leads to a violation of homeostasis, which is supported by a balanced work of the body’s defense systems against oxidative stress, in particular, antioxidant, thiol disulfide and nitric oxide system. The study of these indicators will improve the mechanisms of adaptation of the human body to physical activity.The aim of the study was to identify the features of changes in antioxidant protection systems and nitric oxide during intense physical activity in athletes-swimmers.Materials and methods. Blood of athletes-swimmers (n=30, age 23,0±2,5 years) in the conditions of intensive physical loadings is investigated. Oxidative stress, total serum antioxidant capacity, glutathione levels and nitric oxide metabolites were studied by photometric biochemical methods.Results. In 73.3% of athletes after intense physical activity remained elevated levels of oxidized glutathione, 30% had a high level of oxidative stress, 26.7% of the level of antioxidant capacity of serum is low, 73.3% was reduced relative to the initial level of the concentration of nitric oxide metabolites.Conclusion. Intense physical activity leads to oxidative stress and disturbances in the antioxidant system of the athlete’s body. With increasing load, the degree of violations increases. The level of oxidative stress increases, the total antioxidant capacity of serum decreases, the functioning of glutathione is disrupted. Integral indicators of oxidative stress, as well as glutathione fractions can be recommended for monitoring the state of oxidative stress.

The role of nitric oxide in the antioxidant effect of the non-opiate analogue of leu-enkephalin in the heart of newborn albino rats

The eff ect of the non-opiate analog of leu-enkephalin (peptide NALE: Phe – D – Ala – Gly – Phe – Leu – Arg) on the reactive oxygen species generation in the heart of albino rats in the early postnatal period was studied. Peptide NALE was administered intraperitoneally in the dose of 100 μ/kg daily from 2 to 6 days of life. Reactive oxygen species generation was assessed by chemiluminescence in the heart homogenates of 7-day-old animals. Decreasing of reactive oxygen species generation nearly by 30 % and an increasing in antioxidant system activity by the 20-27 %, compared with the control parameters, were found. The antioxidant eff ect of peptide NALE is associated with the presence of the amino acid Arg in the structure of the peptide. An analogue of NALE peptide, devoid of Arg (peptide Phe – D – Ala – Gly – Phe – Leu – Gly), had a signifi cant lower antioxidant eff ect. The NO-synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in the dose 50 mg/kg, administered with NALE peptide, reduced the severity of the NALE antioxidant eff ect. The results of the study suggest that the pronounced antioxidant eff ect of NALE peptide in the heart of albino rats, at least in part, is due to the interaction with the nitric oxide system.

Changes of Endothelin-1 and Nitric Oxide Systems in Brain Tissue During Mild Hypothermia in a Porcine Model of Cardiac Arrest.

Our previous study found that mild hypothermia (MH) after resuscitation reduced cerebral microcirculation, but the mechanism was not elucidated. The aim of this study was to clarify changes of endothelin-1 (ET-1) and nitric oxide (NO) systems in brain tissue during hypothermia after resuscitation. Twenty-six domestic male Beijing Landrace pigs were used in this study. MH was intravascularly induced 1h after resuscitation from 8-min ventricular fibrillation. Core temperature was reduced to 33°C and maintained until 8h after resuscitation, and then animals were euthanized. ET-1 and NO levels in brain tissue and peripheral plasma were measured. Expression of endothelin-converting enzyme-1 (ECE-1), endothelin A receptor (ET-AR), endothelin-B receptor, and nitric oxide synthase (NOS) in brain tissue was determined by Western blot analysis. Compared with non-hypothermia (NH) treatment, MH after resuscitation significantly increased the level of endothelin-1 and reduced the level of NO in peripheral blood and brain tissue. Cerebral expression of ECE-1 and ET-AR was significantly increased during MH after resuscitation. Moreover, MH significantly decreased inducible NOS expression compared with the NH group. The ET-1 system is activated, while inducible NOS is inhibited in brain tissue during MH after resuscitation.

Role of Myeloperoxidase, Paraoxonase, and Nitric Oxide System in the Blood and Pericardial Fluid of Patients with Ischemic Heart Disease after Direct Myocardial Revascularization

To study the role of paraoxonase, myeloperoxidase, arginase, asymmetric dimethylarginine, and nitric oxide in the mechanisms of the pathogenesis of postpericardiotomy syndrome (PPCS), 76 patients with ischemic heart disease (IHD) who underwent coronary artery bypass grafting were examined. Patients were divided into two groups: Group 1, IHD patients who were not diagnosed with PPCS as a result of clinical studies, and Group 2, IHD patients who were diagnosed with PPCS. The results indicate that the postoperative period after coronary artery bypass grafting is associated with the inhibition of paraoxonase, the activation of myeloperoxidase, enhanced arginase activity, increased nitrite/nitrate and asymmetric dimethylarginine levels; it may also be accompanied by the development of endothelial dysfunction and increased systemic inflammatory response. In the present work, inverse correlations were found between the paraoxonase aryl esterase activity and myeloperoxidase activity in plasma, as well as the paraoxonase aryl esterase activity in blood plasma and arginase activity in erythrocytes in patients of both groups. Tests to predict the development of postpericardiotomy syndrome were developed based on the ratio of activity of the studied enzymes.

Gut microbiota: an overlooked factor that plays a significant role in osteoporosis.

Gut microbes are known as the body’s second gene pool. Symbiotic intestinal bacteria play a major role in maintaining balance in humans. Bad eating habits, antibiotic abuse, diseases, and a poor living environment have a negative effect on intestinal flora. Abnormal intestinal microbes are prone to cause a variety of diseases, affecting life expectancy and long-term quality of life, especially in older people. Several recent studies have found a close association between intestinal microorganisms and osteoporosis. The potential mechanism of intestinal flora affecting bone formation or destruction by mediating nitric oxide, the immune and endocrine systems, and other factors is briefly described in this review. All of these factors may be responsible for the intestinal flora that causes osteoporosis. Studying the relationship between intestinal flora and bone health not only provides new ideas for studying the role of intestinal microorganism in osteoporosis, but also provides a new therapeutic direction for clinically refractory osteoporosis. Study of the relationship between intestinal microbiota and osteoporosis is important for maintaining bone health and minimizing osteoporosis.

Anti-inflammatory and anti-osteoarthritis effects of Cm-02 and Ck-02

Osteoarthritis (OA) is a common degenerative joint disease characterized by progressive deterioration of articular cartilage. There have been reports that small molecule inhibitors have anti-osteoarthritis effects; however, the effects of 3-(4-chloro-2-fluorophenyl)-6-(2,4-difluorophenyl)-2H-benzo[e] [1,3]oxazine-2,4(3H)-dione (Cm-02) and 6-(2,4-difluorophenyl)-3-(3,4-difluorophenyl)-2H-benzo[e] [1,3]oxazine-2,4(3H)-dione (Ck-02), small molecule inhibitors which share many structural similarities with quercetin (a potent anti-inflammatory flavonoid), remain unclear. In this study, TNF-α-stimulated porcine and human chondrocyte models were used to investigate the inhibitory effects of Cm-02 and Ck-02 on the molecular mechanisms underlying the anti-OA effects. TNF-α was used to stimulate porcine and human chondrocytes to mimic immunomodulatory potency in-vitro. Anti-osteoarthritic effects were characterized in terms of protein and mRNA levels associated with the pathogenesis of OA. We also examined (1) the inducible nitric oxide synthase (iNOS)-nitric oxide (NO) system in cultured chondrocytes, (2) matrix metalloproteinases (MMPs) in cultured chondrocytes, and (3) aggrecan degradation in cartilage explants. Finally, we tested the activation of nuclear factor-kappaB (NF-κB), interferon regulatory factor-1 (IRF-1), and activate the protein-1 (AP-1), and we tested the signal transduction and activation of transcription-3 (STAT-3). Our results indicate that, in chondrocytes, Cm-02 and Ck-02 inhibit TNF-α induced NO production, iNOS, MMP, the expression of disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), and the enzyme activity of MMP-13. Furthermore, both Cm-02 and Ck-02 were found to stimulate TNF-α, which has been shown to suppress the activation of several transcription factors, including NF-κB, STAT-3, and IRF-1 in porcine and human chondrocytes. Cm-02 and Ck-02 were also found to help prevent the release of proteoglycans from cartilage explants. Our findings demonstrate that both Cm-02 and Ck-02 have potent anti-inflammatory activities and the ability to protect cartilage in an OA cell model. These findings indicate that Cm-02 and Ck-02 have the potential to be further developed for the therapeutic treatment of OA.

Chronic treatment with C-type natriuretic peptide impacts differently in the aorta of normotensive and hypertensive rats.

The aim of this study was to determine whether exogenous administration of C-type natriuretic peptide (CNP) induces functional and morphological vascular changes in spontaneously hypertensive rats (SHR) compared with normotensive rats. Male 12-week-old normotensive Wistar and SHR were administered with saline (NaCl 0.9%) or CNP (0.75μg/h/100g) for 14days (subcutaneous micro-osmotic pumps). Systolic blood pressure (SBP) was measured in awake animals and renal parameters were evaluated. After decapitation, the aorta was removed, and vascular morphology, profibrotic markers, and vascular reactivity were measured. In addition, nitric oxide (NO) system and oxidative stress were evaluated. After 14-days of treatment, CNP effectively reduced SBP in SHR without changes in renal function. CNP attenuated vascular remodeling in hypertensive rats, diminishing both profibrotic and pro-inflammatory cytokines. Also, CNP activated the vascular NO system and exerted an antioxidant effect in aortic tissue of both groups, diminishing superoxide production and thiobarbituric acid-reactive substances, and increasing glutathione content. These results show that chronic treatment with CNP attenuates the vascular damage development in a model of essential hypertension, inducing changes in fibrotic, inflammatory, oxidative, and NO pathways that could contribute to beneficial long-term effects on vascular morphology, extracellular matrix composition, and function. The knowledge of these effects of CNP could lead to improved therapeutic strategies to not only control BP but also reduce vascular damage, primarily responsible for the risk of cardiovascular events.

Review of modern phlebotrophic preparations based on flavonoids as perspective endothelioprotectors in the treatment of chronic diseases of the veins

This review examines the development of endothelial dysfunction in chronic venous diseases (СVD), the multifactority of this process. The important role of the nitric oxide system as a universal modulator of various biochemical reactions and realization of many important physiological functions is shown. The need for early pharmacotherapy of phleboprotectors with endothelioprotective activity is discussed in order to slow the progression of CVD. Effects of flavonoids as perspective endothelioprotectors on various links in the pathogenesis of endothelial dysfunction are considered. On the example of the micronized purified flavonoid fraction (MPFF), the effect of flavonoid compounds on endothelial dysfunction in CVD is demonstrated, and the mechanisms of action have been examined in detail. In addition, the pharmacological effects of individual components of the MPFF and their synergism in the focus on the effect on endothelial dysfunction are also discussed. Features of the micronized form that affect bioavailability and, ultimately, determine the pharmacological effectiveness of the drug are considered.

Epigenetic regulation of intercellular communication in the heart.

The myocardium is a highly structured tissue consisting of different cell types including cardiomyocytes, endothelial cells, fibroblasts, smooth muscle cells, inflammatory cells, and stem cells. Microvascular endothelial cells are the most abundant cell type in the myocardium and play crucial roles during cardiac development, in normal adult myocardium, and during myocardial diseases such as heart failure. In the last decade, epigenetic changes have been described regulating cellular function in almost every cell type in the organism. Here, we review recent evidence on different epigenetic changes that regulate intercellular communication in normal myocardium and during myocardial diseases, including cardiac remodeling. Epigenetic changes influence many intercellular communication signaling systems, including the nitric oxide, angiotensin, and endothelin signaling systems. In this review, we go beyond discussing classic endothelial function (for instance nitric oxide secretion) and will discuss epigenetic regulation of intercellular communication.

Amitriptyline at an Environmentally Relevant Concentration Alters the Profile of Metabolites Beyond Monoamines in Gilt-Head Bream.

The antidepressant amitriptyline is a widely used selective serotonin reuptake inhibitor that is found in the aquatic environment. The present study investigates alterations in the brain and the liver metabolome of gilt-head bream (Sparus aurata) after exposure at an environmentally relevant concentration (0.2 µg/L) of amitriptyline for 7 d. Analysis of variance-simultaneous component analysis is used to identify metabolites that distinguish exposed from control animals. Overall, alterations in lipid metabolism suggest the occurrence of oxidative stress in both the brain and the liver-a common adverse effect of xenobiotics. However, alterations in the amino acid arginine are also observed. These are likely related to the nitric oxide system that is known to be associated with the mechanism of action of antidepressants. In addition, changes in asparagine and methionine levels in the brain and pantothenate, uric acid, and formylisoglutamine/N-formimino-L-glutamate levels in the liver could indicate variation of amino acid metabolism in both tissues; and the perturbation of glutamate in the liver implies that the energy metabolism is also affected. These results reveal that environmentally relevant concentrations of amitriptyline perturb a fraction of the metabolome that is not typically associated with antidepressant exposure in fish. Environ Toxicol Chem 2019;00:1-13. © 2019 SETAC.

Mortality in critical illness: The impact of asymmetric dimethylarginine on survival-A systematic review and meta-analysis.

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of the nitric oxide system, may be associated with an adverse outcome in critically ill patients. The aim of the present review was to clarify if plasma ADMA and the arginine-to-ADMA ratio (arginine/ADMA) are associated with mortality in critically ill patients. We searched PubMed, EMBASE and Web of Science/BIOSIS Previews on 31 July 2017 for studies published after 2000 including critically ill paediatric or adult patients and evaluating any association between all-cause mortality and admission ADMA and/or arginine/ADMA ratio. We pooled data from studies providing sufficient data in random effects meta-analyses. We identified 15 studies including a total of 1300 patients. These studies have a medium to high risk of bias and substantial clinical heterogeneity. After contacting authors for homogenous data, six studies including 705 patients could be included in a formal meta-analysis. This analysis revealed a strong association between high plasma ADMA upon admission and mortality (pooled odds ratio 3.13; 95% confidence interval (CI) 1.78-5.51). A significant association between ADMA/arginine ratio and mortality was found in two studies only (54 patients) out of a total of six studies (564 patients). A high plasma ADMA level upon admission is strongly associated with mortality in critically ill patients. However, there is no association between the arginine/ADMA ratio and mortality in this group of patients. The pathophysiological role of ADMA in circulatory collapse and its potential as a target for intervention remains to be explored.

Protective effects of exercise on heart and aorta in high-fat diet-induced obese rats

We investigated the protective effects of swimming exercise on high-fat diet-induced heart and aorta damage by evaluating oxidative stress and the endothelial nitric oxide (NO) system. Sprague Dawley rats were fed either standard chow (STD, 6% fat) or high-fat diet (HFD; 45% fat) for 18 weeks, with half of the animals trained by daily swimming sessions (EXC; 1 h per day for 5 days/week) for the last 6 weeks of the experimental period and half kept sedentary (SED). Heart and aorta tissues were prepared for routine light and electron microscopy evaluation. Endothelial NOS (eNOS) and inducible NOS (iNOS) distribution in the tissue samples were examined by immunohistochemistry. Biochemical examinations, including blood serum lipid profiles, malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and tissue NO levels were measured. Deteriorated heart and aorta morphology, increased MDA levels and iNOS-immunoreactivity (iNOS-ir), as well as decreased GSH, NO, SOD, and eNOS-ir parameters were observed in the HFD + SED group. These morphological and biochemical parameters were ameliorated in the HFD + EXC group. Our study revealed that obesity-induced iNOS activation and increased oxidative stress in cardiac and aorta tissues. Exercise protected the obesity-induced cardiac and aortic tissue damage by modulating oxidant/antioxidant balance via involvement of the NO system.

Blockade of NMDA Receptors and Nitric Oxide Synthesis Potentiated Morphine-Induced Anti-Allodynia via Attenuating Pain-Related Amygdala pCREB/CREB Signaling Pathway

The present study investigated the role of the amygdala N-methyl-d-aspartate (NMDA) receptors/nitric oxide synthase pathway in morphine-induced anti-allodynia. Concurrently with the bilateral cannulation of the central amygdala, chronic constriction of the sciatic nerve was performed on male Wistar rats. Morphine (3–5 mg/kg) was administered intraperitoneally to induce anti-allodynia. When D-AP5, a selective NMDA receptor antagonist, (.05–.1 µg/rat) or NG-Nitro-L-arginine methyl ester hydrochloride (L-NAME), the nitric oxide synthase inhibitor (.1–.5 µg/rat), were microinjected into the central amygdala, the higher doses potentiated an ineffective dose of morphine (3 mg/kg). Microinjection of the same doses of D-AP5 and L-NAME without morphine had no effect. Comicroinjection of the ineffective doses of L-NAME (.1 µg/rat) and D-AP5 (.05 µg/rat) with a 5-minute interval, enhanced the anti-allodynic effect of morphine (3 mg/kg). Western blot analysis was employed to evaluate the levels of cyclic adenosine monophosphate-response element-binding protein (CREB) and phosphorylated CREB (pCREB) in the amygdala tissues. Our results showed that neuropathic pain increased the pCREB/CREB ratio in the amygdala, and this ratio was decreased after morphine-induced anti-allodynia. The potentiative effect of the coadministration of D-AP5/L-NAME on an ineffective dose of morphine also decreased the amygdala pCREB/CREB levels. Therefore, it seems that the amygdala pCREB/CREB signaling pathway plays a critical role in processing neuropathic pain. Moreover, the glutamate NMDA receptors and nitric oxide system in the amygdala may be involved in morphine-induced anti-allodynia. PerspectiveNeuropathic pain is difficult to treat and the exact mechanisms remain unknown. This article suggests the importance of the amygdala glutamatergic and nitric oxide systems in morphine-induced anti-allodynia. These findings might be used in clinical studies to reach a better understanding of neuropathic pain mechanisms and treatment.

The response of nitric oxide system to high Altitude in Phrynocephalus erythrurus on Qinghai-Tibetan plateau.

Nitric oxide (NO), produced by nitric oxide synthases (NOS) from L-arginine, plays important roles in a wide range of physiological processes. However, little is known about ectothermic species. To investigate the response of NO/NOS system in adaptation to different altitudes in Phrynocephalus genus, the red tail toad-headed lizard Phrynocephalus erythrurus that live at 4500-5300 m on the Qinghai-Tibet Plateau and another low altitude living lizard Phrynocephalus przewalskii were selected in the present study. The results of mRNA expression and activity of NOSs, as well as NO metabolite levels in different tissues of the two lizards indicate that nNOS mRNA levels in cardiac and skeletal muscle were notably elevated in P. erythrurus, and iNOS expression was also increased markedly (up to 4-fold) in cardiac muscle. There was no significant difference in eNOS mRNA level in tested tissues between two species. However, the total NOS activity in skeletal muscle of P. erythrurus was slightly lower than that of P. przewalskii (p < .05) while no difference in other tissues. Similarly, lower iNOS activity (p < .01) was found in cardiac and skeletal muscle in P. erythrurus compared to P. przewalskii. In addition, the NO metabolite levels were dramatically lower in P. erythrurus in all tested tissues. We propose that higher nNOS and iNOS mRNA expression, lower iNOS activity and NO metabolite levels may represent physiological characteristics in nitric oxide system, which may contribute to high-altitude adaptation in P. erythrurus.

Effects of plane of nutrition and arginine on ovarian follicles in non-pregnant sheep: Cell proliferation, and expression of endothelial nitric oxide and its receptor

The aim of this study was to investigate the role of the nitric oxide (NO) system in ovarian function, by determining if arginine (Arg) supplementation impacts follicle number, cell proliferation, and expression of the NO system members in nutritionally compromised ewes. Ewes were randomly assigned into maintenance (C, 100% requirements), excess (O; 2xC), or restricted (U; 0.6xC) diets 8 weeks prior to Arg treatment. Ewes were individually fed twice daily with pelleted diets. Ewes from each nutritional group were randomly assigned to one of two treatments: saline or Arg, which was initiated on day 0 of the estrous cycle and administered 3 times per day. Ovaries were collected at the early-luteal, mid-luteal and late-luteal/follicular phases of the estrous cycle to determine 1) the number of surface follicles, 2) follicle cell proliferation marked by Ki67 protein expression, and 3) expression of endothelial nitric oxide (eNOS; NOS3) and soluble guanylyl cyclase beta (sGC; GUCY1B3) protein and mRNA in granulosa (G) and theca (T) layers using immunohistochemistry followed by image analysis and qPCR, respectively. During nutritional treatment, C maintained body weight, O gained 6±1.2 kg, and U lost 14±1.3 kg. Our data show that: 1) Ki67 was expressed in all ovarian compartments, eNOS protein was detected in blood vessels of T and stroma, and sGC protein was detected in T cells, and blood vessels of T layer and other ovarian compartments; 2) plane of nutrition affected the number of surface follicles, and thus folliculogenesis, cell proliferation in the T layer, eNOS and sGC protein expression in T, and NOS3 and GUCY1B3 mRNA expression in G; 3) Arg treatment affected cell proliferation in G and T, eNOS and sGC protein expression in T, mRNA expression of NOS3 in T in all groups, and GUCY1B3 in G depending on the stage of the estrous cycle; and 4) G and T cell proliferation, and expression of eNOS and sGC protein in T was affected by the stage of the estrous cycle. Our data demonstrated that plane of nutrition and Arg are involved in the regulation of follicular functions in non-pregnant sheep.

Consumption of decaffeinated coffee protects against the development of early non-alcoholic steatohepatitis: Role of intestinal barrier function

BackgroundNon-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide lacking universally accepted therapies. Studies suggest that coffee consumption is associated with a reduced risk of NAFLD; however, molecular mechanisms and ingredients involved remain to be fully understood. Here, we determined the effects of regular intake of decaffeinated coffee on the development of NAFLD in mice, and molecular mechanisms involved. MethodsFemale C57BL/6J mice (n = 6–7/ group) were pair-fed either a liquid control diet (C) or fat-, fructose- and cholesterol-rich diet (FFC) +/- decaffeinated coffee (DeCaf, 6 g/kg BW) for 4 days or 6 weeks. Indices of liver damage, hepatic inflammation and parameters of insulin resistance and intestinal permeability as well as nitric oxide system were determined. ResultsEarly signs of insulin resistance and non-alcoholic steatohepatitis (NASH) found after 6 weeks of FFC feeding were significantly lower in FFC+DeCaf-fed mice when compared to FFC-fed animals. Moreover, elevation of portal endotoxin levels and loss of tight junction proteins in proximal small intestine found in FFC-fed mice were significantly attenuated in FFC+DeCaf-fed animals. These beneficial effects of DeCaf were associated with a protection against the significant induction of inducible NO-synthase protein levels and 3-nitrotyrosine protein adducts found in proximal small intestine of FFC-fed mice. Similar protective effects of DeCaf were also found in mice fed the FFC diet short-term. ConclusionOur results suggest that protective effects of DeCaf on the development of NAFLD are at least in part related to maintaining intestinal barrier function.

Bypassing major venous occlusion and duodenal lesions in rats, and therapy with the stable gastric pentadecapeptide BPC 157, L-NAME and L-arginine.

AIMTo investigate whether duodenal lesions induced by major venous occlusions can be attenuated by BPC 157 regardless nitric oxide (NO) system involvement.METHODSMale Wistar rats underwent superior anterior pancreaticoduodenal vein (SAPDV)-ligation and were treated with a bath at the ligated SAPDV site (BPC 157 10 μg, 10 ng/kg per 1 mL bath/rat; L-NAME 5 mg/kg per 1 mL bath/rat; L-arginine 100 mg/kg per 1 mL bath/rat, alone and/or together; or BPC 157 10 μg/kg instilled into the rat stomach, at 1 min ligation-time). We recorded the vessel presentation (filled/appearance or emptied/disappearance) between the 5 arcade vessels arising from the SAPDV on the ventral duodenum side, the inferior anterior pancreaticoduodenal vein (IAPDV) and superior mesenteric vein (SMV) as bypassing vascular pathway to document the duodenal lesions presentation; increased NO- and oxidative stress [malondialdehyde (MDA)]-levels in duodenum.RESULTSUnlike the severe course in the SAPDV-ligated controls, after BPC 157 application, the rats exhibited strong attenuation of the mucosal lesions and serosal congestion, improved vessel presentation, increased interconnections, increased branching by more than 60% from the initial value, the IAPDV and SMV were not congested. Interestingly, after 5 min and 30 min of L-NAME and L-arginine treatment alone, decreased mucosal and serosal duodenal lesions were observed; their effect was worsened at 24 h, and no effect on the collateral vessels and branching was seen. Together, L-NAME+L-arginine antagonized each other’s response, and thus, there was an NO-related effect. With BPC 157, all SAPDV-ligated rats receiving L-NAME and/or L-arginine appeared similar to the rats treated with BPC 157 alone. Also, BPC 157 in SAPDV-ligated rats normalized levels of NO and MDA, two oxidative stress markers, in duodenal tissues.CONCLUSIONBPC 157, rapidly bypassing occlusion, rescued the original duodenal flow through IAPDV to SMV flow, an effect related to the NO system and reduction of free radical formation.

Characteristics of the nitric oxide system indicators in the left ventricle myocardium in SHR

The aim was to determine the morpho-functional parameters of the left ventricular myocardium NO system in the rats with essential hypertension (SHR line). Material and methods. We used a combination of modern highly informative methods, namely: research of NOS isoform profie (nNOS, iNOS eNOS) in the myocardial slices along with an assessment of their synthesis and expression of the corresponding mRNA; NO derived nitrites level determination directly in the myocardium homogenates and concentration of nitrotyrosine in blood plasma of rats. The results of the performed studies have shown that high blood pressure in the SHR was accompanied by a signifiant increase in the concentrations of all three NOS isoforms in the myocardium and increased expression of their mRNA. Higher concentration of nitrites by 18.8 % was detected in the SHR group compared with the control animals. The concentration of nitrotyrosine in blood plasma of rats with essential hypertension was also increased by 25 %. Conclusions. The predominance of IRM to constitutive isoforms of NOS with low IRM content to iNOS was noted in the myocardium of the control group rats while in SHR rats higher IRM values were marked for all NOS isoforms. The formation of hypertension is accompanied by high content of NO end metabolites and the development of systemic nitroso-oxidative stress with the increase of nitrotyrosine concentration.

SUR2B/Kir6.1 channel openers correct endothelial dysfunction in chronic heart failure via the miR-1-3p/ET-1 pathway

The SUR2B/Kir6.1 channel openers iptakalim and natakalim reverse cardiac remodeling and ameliorate endothelial dysfunction by re-establishing the balance between the nitric oxide and endothelin systems. In this study, we investigated the microRNAs (miRs) involved in the molecular mechanisms of SUR2B/Kir6.1 channel opening in chronic heart failure. Both iptakalim and natakalim significantly upregulated the expression of miR-1-3p, suggesting that this miR is closely associated with the therapeutic effects against chronic heart failure. Bioinformatic analysis showed that many of the 183 target genes of miR-1-3p are involved in cardiovascular diseases, suggesting that miR-1-3p plays a vital role in such diseases and vascular remodeling. Target gene prediction showed that miR-1-3p combines with the 3′ untranslated region (UTR) of endothelin-1 (ET-1) mRNA. Iptakalim and natakalim upregulated miR-1-3p expression and downregulated ET-1 mRNA expression in vitro. The dual luciferase assay confirmed that there is a complementary binding sequence between miR-1-3p and the 3′ UTR 158–165 sequence of ET-1 mRNA. To verify the effect of miR-1-3p on ET-1, lentiviral vectors overexpressing or inhibiting miR-1-3p were constructed for the transduction of rat primary cardiac microvascular endothelial cells. The results showed that natakalim enhanced the miR-1-3p level. miR-1-3p overexpression downregulated the expression of ET-1, whereas miR-1-3p inhibition had the opposite effect. Therefore, we verified that SUR2B/Kir6.1 channel openers could correct endothelial imbalance and ameliorate chronic heart failure through the miR-1-3p/ET-1 pathway in endothelial cells. Our study provides comprehensive insights into the molecular mechanisms behind the SUR2B/Kir6.1 channel’s activity against chronic heart failure.

Changes in the vasoactive effects of nitric oxide, hydrogen sulfide and the structure of the rat thoracic aorta: the role of age and essential hypertension.

Several studies have already confirmed the specific vasomotor effect of hydrogen sulfide (H2S) and its interaction with the nitric oxide (NO) system in normotensive rats, but results in spontaneously hypertensive rats (SHRs) are limited. the aim of this study was to describe the age- and blood pressure-dependent effects of endogenous NO and exogenous Na2S and their interaction in vasomotor responses of the thoracic aorta (TA) in normotensive Wistar rats and SHRs. the systolic blood pressure (sBP), vasoactivity, NO-synthase (NOS) expression and activity, cystathionine gamma-lyase (CSE) expression, and geometry of the isolated TA were evaluated at 4 and 16 weeks of age. Although hypertrophy of the heart was observed in young and adult SHRs, the sBP was increased only in adulthood. the contractile responses were decreased in young as in adult SHRs with the key participation of the endogenous NO system. however, the hypotrophy in the young and the hypertrophy (mainly at the expense of extracellular matrix) in the adult SHRs were found in the TA. While unchanged in young SHRs, in adult SHRs, partially impaired endothelial function was confirmed. Nevertheless, the NO-dependent component of acetylcholine-induced relaxation was higher in both young and adult SHRs. Consistently, even though there was an age-dependent decrease in NOS activity in both strains, NOS activity was higher in both young and adult SHRs compared to age-matched normotensive rats. Application of exogenous Na2S evoked a concentration-dependent dual vasoactive effect of TAs in both strains, regardless of age. Increased sensitivity in favor of vasorelaxant responses of Na2S in prehypertensive SHRs, and an enhanced maximal vasorelaxation in adult SHR was observed. the acute NO inhibition generally increased the relaxant phase of Na2S responses; nevertheless, the development of hypertension potentiated this effect. the TA of the SHRs is endowed with a unique inherent predisposition of vasoactive mechanisms, which serve as compensatory processes during the developed stage of hypertension: the NO component and H2S signaling pathways are implicated. the decreased contractility seems to be a deleterious effect. the increased participation of the H2S system on vasorelaxation after acute NO inhibition could be considered a reserved mechanism in case of endogenous NO deficiency.