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Summary: Erectile dysfunction (ED) is defined in relation to the metabolic syndrome (metS). Hydrogen sulphide (H2S), a gasotransmitter, has been revealed to get involved in hypertension, insulin secretion and regulation of vascular tone especially in erectile physiology. This study aimed to investigate the effect of H2S on metS‐induced ED. Animals were divided into two groups as control and metS, which were fed with standard diet or 60% high‐fructose diet for 10 weeks respectively. The metS model was evaluated with biochemical analyses, waist circumference/tibia length ratio and HOMA index. Penile hemodynamic parameters were evaluated by the measurement of intracavernous pressure/mean arterial pressure ratio during cavernous nerve stimulation in the presence and absence of intracavernous injection of NaHS (100 μg/50 μl) and its control 0.9%NaCl (50 μl) in both groups. H2S levels were measured in penile tissues by methylene blue assay. H2S levels were significantly decreased in the penile tissues of the metS group. Decreased intracavernous pressure/mean arterial pressure ratio improved after intracavernous administration of NaHS in the metS group. These results suggest the significant role of H2S in the metS‐induced erectile dysfunction that could be a new therapeutic target. [ABSTRACT FROM AUTHOR]

OBJECTIVE: A reduction in GSH and an increase in free radicals are observed in inflammatory diseases, indicating oxidative stress. Taurine protects cells from the cytotoxic effects of inflammation. There have been limited studies to date evaluating the effect of taurine in oxidative stress-induced vascular dysfunction and its role in vascular inflammatory diseases. Therefore, we aimed to investigate the effect of taurine on the regulation of vascular tonus and vascular inflammatory markers in rabbit aortae and carotid arteries in oxidative stress-induced by GSH depletion. MATERIALS AND METHODS: Rabbits were treated subcutaneously with buthionine sulfoximine (BSO), GSH-depleting compound and/or taurine. Cumulative concentration-response curves for acetylcholine (ACh), phenylephrine and 5-hydroxytriptamine (5-HT) were constructed with or without Nω-nitro-L-arginine (LNA) in the carotid artery and aorta rings. Immunohistochemical staining was performed for TNF-α and IL-1β. RESULTS: BSO increased ACh-induced NOdependent relaxations, phenylephrine-induced contractions in the carotid artery and 5-HT induced- contractions in both the carotid artery and the aorta. BSO decreased EDHF dependent relaxations only in the aorta. ACh-induced NOdependent relaxations and augmented contractions were normalized by taurine. BSO increased TNF-α expressions in both carotid arteries and aortas, which were reversed by taurine. The BSO-induced increase in IL-1β was reversed by taurine only in aortae. CONCLUSIONS: Treatment with BSO resulted in vascular reactivity changes and increased immunostaining of TNF-α in mainly carotid arteries in this model of oxidative stress. The effect of taurine on BSO-induced vascular reactivity changes varied depending on the vessel. The inhibition of the increase in TNF-α expression by taurine in both carotid arteries and aortae supports the proposal that taurine has a beneficial effect in the treatment of inflammatory diseases such as atherosclerosis. [ABSTRACT FROM AUTHOR]

Vascular ageing, characterized by structural and functional changes in blood vessels of which arterial stiffness and endothelial dysfunction are key components, is associated with increased risk of cardiovascular and other age-related diseases. As the global population continues to age, understanding the underlying mechanisms and developing effective therapeutic interventions to mitigate vascular ageing becomes crucial for improving cardiovascular health outcomes. Therefore, this review provides an overview of the current knowledge on pharmacological modulation of vascular ageing, highlighting key strategies and promising therapeutic targets. Several molecular pathways have been identified as central players in vascular ageing, including oxidative stress and inflammation, the renin-angiotensin-aldosterone system, cellular senescence, macroautophagy, extracellular matrix remodelling, calcification, and gasotransmitter-related signalling. Pharmacological and dietary interventions targeting these pathways have shown potential in ameliorating age-related vascular changes. Nevertheless, the development and application of drugs targeting vascular ageing is complicated by various inherent challenges and limitations, such as certain preclinical methodological considerations, interactions with exercise training and sex/gender-related differences, which should be taken into account. Overall, pharmacological modulation of endothelial dysfunction and arterial stiffness as hallmarks of vascular ageing, holds great promise for improving cardiovascular health in the ageing population. Nonetheless, further research is needed to fully elucidate the underlying mechanisms and optimize the efficacy and safety of these interventions for clinical translation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Prevention of cardiovascular disease (CVD) remains one of the largest public health challenges of our time. Identifying individuals at increased cardiovascular risk at an asymptomatic, sub-clinical stage is of paramount importance for minimizing disease progression as well as the substantial health and economic burden associated with overt CVD. Vascular ageing (VA) involves the deterioration in vascular structure and function over time and ultimately leads to damage in the heart, brain, kidney, and other organs. Vascular ageing encompasses the cumulative effect of all cardiovascular risk factors on the arterial wall over the life course and thus may help identify those at elevated cardiovascular risk, early in disease development. Although the concept of VA is gaining interest clinically, it is seldom measured in routine clinical practice due to lack of consensus on how to characterize VA as physiological vs. pathological and various practical issues. In this state-of-the-art review and as a network of scientists, clinicians, engineers, and industry partners with expertise in VA, we address six questions related to VA in an attempt to increase knowledge among the broader medical community and move the routine measurement of VA a little closer from bench towards bedside., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: Hydrogen sulfide (H2S), known as a third gasotransmitter, is a signaling molecule that plays a regulatory role in physiological and pathophysiological processes. Decreased H2S levels were reported in inflammatory respiratory diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary hypertension. H2S donors or drugs that increase H2S have emerged as novel treatments for inflammatory respiratory diseases. We previously showed that resveratrol (RVT) causes vascular relaxation and antioxidant effects by inducing H2S production. In the current study, we synthesized a new molecule Cpd2, as an RVT analog. We examined the effect of Cpd2 and its precursor chalcone compound (Cpd1) on H2S formation under both healthy and oxidative stress conditions in the lung, as well as vascular relaxation in the aorta., Methods: Cpd2 synthesized from Cpd1 with microwaved in basic conditions. H2S formation was measured by H2S biosensor in the mice lungs under both healthy and pyrogallol-induced oxidative stress conditions in the presence/absence of H2S synthesis inhibitor aminooxyacetic acid (AOAA). The effect of compounds on vascular tonus is investigated in mice aorta by DMT myograph., Results: RVT and Cpd2 significantly increased l-cysteine (l-cys) induced-H2S formation in the lung homogenates of healthy mice, but Cpd1 did not. Superoxide anion generator pyrogallol caused a decrease in H2S levels in mice lungs and Cpd2 restored it. Inhibition of Cpd2-induced H2S formation by AOAA confirmed that Cpd2 increases endogenous H2S formation in both healthy and oxidative stress conditions. Furthermore, we found that both Cpd1 and Cpd2 (10-8-10-4 M) caused vascular relaxation in mice aorta., Discussion and Conclusion: We found that Cpd2, a newly synthesized RVT analog, is an H2S-inducing molecule and vasorelaxant similar to RVT. Since H2S has antioxidant and anti-inflammatory effects, Cpd2 has a potential for the treatment of respiratory diseases where oxidative stress and decreased H2S levels are present., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Erectile dysfunction (ED) is the inability to achieve/maintain an erection. Because of the side effects, interactions, or ineffectiveness of currently used drugs, novel drug discovery studies are ongoing. The roots of Turkish endemic plants Prangos uechtritzii and Prangos heyniae are traditionally used as aphrodisiacs in Anatolia and contain coumarin-like relaxant compounds. This study aims to reveal the relaxant effect mechanisms of chloroform root extracts of P. heyniae (Ph-CE) and P. uechtritzii (Pu-CE). Isolated organ bath experiments were performed on Swiss albino mouse corpus cavernosum by DMT strip myograph. Relaxant responses to extract (10 -7 -10 -4  g/ml) were obtained in the presence/absence of NO and H 2 S synthesis inhibitors nitro-l-arginine methyl ester (l-NAME, 100 μM) and aminooxyacetic acid (AOAA, 10 mM) respectively. Sodium nitroprusside (SNP, 10 -9 to 10 -4  M) and Na 2 S (10 -6 to 3 × 10 -3  M)-induced relaxations and CaCl 2 (10 -6 to 10 -4  M), KCl (10 -2.1 to 10 -0.9  M) and phenylephrine (3 × 10 -8 to 3 × 10 -5  M)-induced contractions were taken in the presence/absence of the extracts (10 -4  g/ml). Relaxations induced by Ph-CE but not by Pu-CE were inhibited in the presence of l-NAME and AOAA. Ph-CE increased Na 2 S- and SNP-induced relaxations. Ph-CE and Pu-CE decreased the contractions of KCl, phenylephrine, and CaCl 2 . It was concluded that NO and H 2 S synthesis/downstream mechanisms play roles in relaxations of Ph-CE but not in Pu-CE-induced relaxations. Inhibition of calcium influx appears to be involved in the relaxant effect of Ph-CE and Pu-CE. Since the extracts act directly by relaxing smooth muscle or through H 2 S as well as NO, they may be a potential therapeutic agent in diseases such as ED where the bioavailability of NO is impaired., (© 2022 Wiley-VCH GmbH.)

Pulmonary arterial hypertension is caused by complex structural and functional changes in the endothelial and smooth muscle cells of pulmonary arteries. Hydrogen sulfide (H 2 S), a gasotransmitter, can potentially treat pulmonary hypertension by relaxing the pulmonary arteries and decreasing bronchial pressure. Although the role of H 2 S in systemic circulation has been examined, the H 2 S levels in pulmonary arteries, the role of H 2 S in endothelium-dependent vasorelaxation and the L-cysteine/H 2 S pathway in monocrotaline-induced pulmonary arterial hypertension have not been investigated. The rats were divided into control, monocrotaline, monocrotaline + Na 2 S, and Na 2 S groups. The right ventricular pressure and hypertrophy were evaluated. KCl, acetylcholine, and L-cysteine responses were obtained in the main pulmonary arteries by wire myograph. H 2 S levels were measured in pulmonary arteries and lungs by methylene blue assay. Right ventricular pressure and hypertrophy were increased by monocrotaline and ameliorated by Na 2 S. The KCl-induced contractions and relaxing responses to acetylcholine and L-cysteine in pulmonary arteries and H 2 S production in the lungs and pulmonary arteries were significantly attenuated in the monocrotaline group and augmented in the monocrotaline + Na 2 S group. These findings suggest that H 2 S levels were reduced, and L-cysteine-induced and endothelium-dependent relaxations were impaired in the pulmonary arteries in monocrotaline-induced pulmonary arterial hypertension. The H 2 S donor, Na 2 S, prevented endothelial dysfunction and increased pulmonary artery pressure and hypertrophy. Also, Na 2 S enhanced the L-cysteine-mediated responses and restored the diminished H 2 S levels in pulmonary arteries and the lungs. The treatments targeting H 2 S might be beneficial for promoting vascular alterations, i.e. endothelial dysfunction and impaired H 2 S-mediated relaxation in pulmonary arterial hypertension., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: Erectile dysfunction (ED) is the most common form of sexual dysfunction which has been the topic of great interest through the history by all cultures. It is now among the most treated health problems in men of all ages that develop under the influence of lifestyle factors and some diseases. Plants are extensively used to cure sexual dysfunction for centuries. Roots of Prangos sp. have been used to improve sexual performance in Anatolian traditional medicine and are rich of coumarin, furanocoumarin and their derivatives. Scientific research is necessary to support and validate the ethno-traditional uses of these plants., Aim of the Study: The aim of this study is to investigate the effects of the root extracts of P. pabularia, P. uechtritzii and P. heyniae on erectile function and to isolate and identify the chemical compounds of the most active extract and reveal possible pharmacological mechanism of the major compound of the extract with the strongest relaxant effect in mouse corpus cavernosum (MCC)., Materials and Methods: The roots of plants were extracted with chloroform, n-hexane and methanol. The compounds were isolated from the extract by column chromatography and structures were identified by NMR and MS. The relaxant effects of extracts (10 -7 -10 -4  g/mL), (+)-oxypeucedanin (10 -7 -10 -4  M) and Na 2 S (10 -7 -3 × 10 -3  M) were tested in MCC strips by DMT myograph. To investigate the mechanism, the synthesis inhibitors of aminooxyacetic acid (AOAA, 10 -2  M) and nitro-L-arginine methyl ester (L-NAME, 10 -4  M) were used, respectively. H 2 S formation was evaluated basal and L-cysteine (L-cyst)-stimulated conditions by H 2 S microsensor., Results: All extracts relaxed MCC in a concentration dependent manner. The maximum relaxing effects were achieved with chloroform extracts. Chloroform extract of P. pabularia (Pp-CE) was more potent than the others. Pp-CE-induced relaxations were significantly decreased by AOAA and L-NAME. (+)-Oxypeucedanin, the major compound of Pp-CE, induced relaxant responses and this effect was inhibited by AOAA, but not L-NAME. The relaxation of (+)-oxypeucedanin was found to be similar in view of E max to positive control H 2 S donor Na 2 S. (+)-Oxypeucedanin increased L-cyst-stimulated H 2 S formation. Augmentation of H 2 S synthesis with (+)-oxypeucedanin was inhibited by AOAA., Conclusions: Pp-CE has the strongest effect on relaxation of MCC and this result supports the traditional aphrodisiac use of P. pabularia root extract in Anatolia. The pharmacological mechanisms of Pp-CE to relax MCC involve NO and H 2 S formation. (+)-Oxypeucedanin could be responsible for the H 2 S-mediated relaxations of Pp-CE in MCC., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Resistin is known as a potential mediator of obesity-associated insulin resistance. The high resistin level disrupts nitric oxide (NO)-mediated relaxation which is also important in erectile function. An antioxidant alkaloid, Boldine, is known as anti-diabetic and protects endothelial functions., Objectives: We aimed to investigate resistin expression in penile tissue in the presence of insulin resistance (IR) and the effect of Boldine treatment on erectile functions in the metabolic syndrome (MetS) rat model., Materials and Methods: Wistar rats were randomly divided into three groups: Control, MetS, and boldine treated MetS group. MetS parameters were assessed by serum triglycerides (TG), uric acid (UA), glucose, insulin levels, HOMA index, and waist circumference (WC)/tibia length (TL) ratio. To evaluate erectile functions, intracavernous pressure (ICP)/mean arterial pressure (MAP) ratio was performed during cavernous nerve stimulation. Protein expressions of resistin, endothelial nitric oxide synthase (eNOS), p(S1177) eNOS, and insulin receptor-β were evaluated by Western blotting., Results: TG, glucose, insulin levels, weight, WC/TL ratio, HOMA index and resistin expression in penile tissue were significantly increased and ICP/MAP values, and p (S1177) eNOS expression in penile tissue were decreased in MetS group. Boldine treatment enhanced ICP/MAP values, insulin receptor-β and p(S1177) eNOS expressions compared with the MetS group., Discussion and Conclusion: MetS caused a deterioration in erectile function accompanied by an increase in resistin expression and a reduction in eNOS enzyme activation in the rat penile tissues. Boldine treatment resulted in an improvement in erectile function, independent of resistin expression., (© 2020 American Society of Andrology and European Academy of Andrology.)

Cotton, a staple fiber that grows around the seeds of the cotton plants (Gossypium), is produced throughout the world, and its by products, such as cotton fibers, cotton-seed oil, and cottonseed proteins, have a variety of applications. Cotton-seed contains gossypol, a natural phenol compound. (±)-Gossypol is a yellowish polyphenol that is derived from different parts of the cotton plant and contains potent anticancer properties. Tumor growth and metastasis are mainly related to angiogenesis; therefore, anti-angiogenic therapy targets the new blood vessels that provide oxygen and nutrients to actively proliferating tumor cells. The aim of the present study was to evaluate the anti-angiogenic potential of (±)-gossypol in vitro. (±)-Gossypol has anti-proliferative effects on cancer cell lines; however, its anti-angiogenic effects on normal cells have not been studied. Anti-proliferative activities of gossypol assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, anti-angiogenic activities using tube formation assay, and cell migration inhibition capability using a wound-healing assay on human umbilical vein endothelial cells (HUVECs) were revealed. (±)-Gossypol displayed the following potent anti-angiogenic activities in vitro: it inhibited the cell viability of HUVECs, it inhibited the migration of HUVECs, and disrupted endothelial tube formation in a dose-dependent manner. In addition, the anti-angiogenic effects of (±)-gossypol were investigated in ovo in a model using a chick chorioallantoic membrane (CAM). Decreases in capillary density were assessed and scored. (±)-Gossypol showed dose-dependent anti-angiogenic effects on CAM. These findings suggest that (±)-gossypol can be used as a new anti-angiogenic agent.

Chronic inflammation is associated to 25% of cancer cases according to epidemiological data. Therefore, inhibition of inflammation-induced carcinogenesis can be an efficient therapeutic approach for cancer chemoprevention in drug development studies. It is also determined that anti-inflammatory drugs reduce cancer incidence. Cell culture-based in vitro screening methods are used as a fast and efficient method to investigate the biological activities of the biomolecules. In addition, saponins are molecules that are isolated from natural sources and are known to have potential for tumor inhibition. Studies on the preparation of analogues of cycloartane-type sapogenols (9,19-cyclolanostanes) have so far been limited. Therefore we have decided to direct our efforts toward the exploration of new anti-tumor agents prepared from cycloastragenol and its production artifact astragenol. The semi-synthetic derivatives were prepared mainly by oxidation, condensation, alkylation, acylation, and elimination reactions. After preliminary studies, five sapogenol analogues, two of which were new compounds (2 and 3), were selected and screened for their inhibitory activity on cell viability and NFκB signaling pathway activity in LNCaP prostate cancer cells. We found that the astragenol derivatives 1 and 2 as well as cycloastragenol derivatives 3, 4, and 5 exhibited strong inhibitory activity on NFκB signaling leading the repression of NFκB transcriptional activation and suppressed cell proliferation. The results suggested that these molecules might have significant potential for chemoprevention of prostate carcinogenesis induced by inflammatory NFκB signaling pathway., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Erectile dysfunction (ED) is defined in relation to the metabolic syndrome (metS). Hydrogen sulphide (H 2 S), a gasotransmitter, has been revealed to get involved in hypertension, insulin secretion and regulation of vascular tone especially in erectile physiology. This study aimed to investigate the effect of H 2 S on metS-induced ED. Animals were divided into two groups as control and metS, which were fed with standard diet or 60% high-fructose diet for 10 weeks respectively. The metS model was evaluated with biochemical analyses, waist circumference/tibia length ratio and HOMA index. Penile hemodynamic parameters were evaluated by the measurement of intracavernous pressure/mean arterial pressure ratio during cavernous nerve stimulation in the presence and absence of intracavernous injection of NaHS (100 μg/50 μl) and its control 0.9%NaCl (50 μl) in both groups. H 2 S levels were measured in penile tissues by methylene blue assay. H 2 S levels were significantly decreased in the penile tissues of the metS group. Decreased intracavernous pressure/mean arterial pressure ratio improved after intracavernous administration of NaHS in the metS group. These results suggest the significant role of H 2 S in the metS-induced erectile dysfunction that could be a new therapeutic target., (© 2017 Blackwell Verlag GmbH.)

The gasotransmitter nitric oxide (NO) has an important role in vascular function and a decrease in its bioavailability is accepted as a main pathological mechanism for cardiovascular diseases. However, other gasotransmitters such as hydrogen sulfide (H 2 S) are also generated by the endothelium and can also affect vascular tone and a crosstalk may exist between H 2 S and NO. We therefore investigated the consequences of deficiency, replacement or overexpression of endothelial nitric oxide synthase (eNOS) on H 2 S-induced vascular responses in murine carotid arteries. In pre-contracted carotid arteries from wild-type (WT) mice, l-cysteine elicited relaxation that was inhibited by the H 2 S synthesis inhibitor amino-oxyacetic acid (AOAA). Genetic deletion of eNOS increased l-cysteine-induced relaxation compared to WT, but the replacement of eNOS by adenoviral transfection or H 2 S synthesis inhibition by AOAA reversed it. Furthermore, eNOS deletion did not alter NaHS-induced relaxation in carotid arteries while eNOS overexpression/replacement increased NaHS-induced relaxation responses in carotid arteries from WT or eNOS -/- . We suggest that, endogenously produced H 2 S can compensate for impaired vasodilatory responses in the absence of NO to maintain vascular patency; while, eNOS abundance can limit endogenous H 2 S-induced vascular responses in mice carotid arteries. Our result suggests that endogenous vs. exogenous H 2 S-induced relaxation are reciprocally regulated by NO in mice carotid arteries., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Reactive oxygen species (ROS) decreases bioavailability of nitric oxide (NO) and impairs NO-dependent relaxations. Like NO, hydrogen sulfide (H 2 S) is an antioxidant and vasodilator; however, the effect of ROS on H 2 S-induced relaxations is unknown. Here we investigated whether ROS altered the effect of H 2 S on vascular tone in mouse aorta and determined whether resveratrol (RVT) protects it via H 2 S. Pyrogallol induced ROS formation. It also decreased H 2 S formation and relaxation induced by l-cysteine and in mouse aorta. Pyrogallol did not alter sodium hydrogensulfide (NaHS)-induced relaxation suggesting that the pyrogallol effect on l-cysteine relaxations was due to endogenous H 2 S formation. RVT inhibited ROS formation, enhanced l-cysteine-induced relaxations and increased H 2 S level in aortas exposed to pyrogallol suggesting that RVT protects against "H 2 S-dysfunctions" by inducing H 2 S formation. Indeed, H 2 S synthesis inhibitor AOAA inhibited the protective effects of RVT. RVT had no effect on Ach-induced relaxation that is NO dependent and the stimulatory effect of RVT on H 2 S-dependent relaxation was also independent of NO. These results demonstrate that oxidative stress impairs endogenous H 2 S-induced relaxations and RVT offers protection by inducing H 2 S suggesting that targeting endogenous H 2 S pathway may prevent vascular dysfunctions associated by oxidative stress., (Copyright © 2016. Published by Elsevier Inc.)

Erectile dysfunction (ED) is considered as a marker for cardiovascular diseases. Nitric oxide (NO) deficiency is the major cause of erectile dysfunction (ED). The role of hydrogen sulfide (H 2 S) in erection has recently been recognized and is receiving attention as a pharmacological target. Several studies have focused on the effect of H 2 S on NO-dependent relaxation, but the role of NO on H 2 S in penile tissue has not been studied yet. Unlike NO, H 2 S is mainly synthesized from smooth muscle cells rather than endothelial cells. We hypothesized that H 2 S may compensate for the decreased NO bioavailability and may be beneficial in severe ED where endothelial dysfunction is present. Thus we studied the effect of NO deficiency on H 2 S formation and vasorelaxation induced by l-cysteine, which is the substrate of the H 2 S producing enzymes in mice corpus cavernosum (MCC). NO deficiency induced by Nω-Nitro-l-arginine (L-NNA) was confirmed by the inhibition of acetylcholine-induced relaxation. l-cysteine, the substrate for the endogenous H 2 S production, caused a concentration-dependent relaxation that was reduced by CBS/CSE inhibitor aminooxyacetic acid (AOAA) in MCC strips. L-NNA caused a significant increase in l-cysteine-induced relaxation, and this effect was reversed by AOAA. On the contrary, no change in relaxation to NaHS (exogenous H 2 S donor) in MCC was observed. L-NNA increased H 2 S formation stimulated by l-cysteine in wild type MCC but not in CSE -/- mice. In parallel, the expression of both cysthationine γ lyase (CSE) and 3-mercaptopyruvate sulphurtransferase (3-MST) was increased, whereas cysthationine-β synthase (CBS) was decreased in eNOS -/- MCC. We conclude that H 2 S plays a compensatory role in the absence of NO by enhancing the relaxation induced by endogenous H 2 S through CSE and 3-MPST in MCC, without altering downstream mechanisms. We suggest that H 2 S-targeting drugs may provide the maintenance of compensatory treatment in ED patients. This may be more relevant in ED with severe endothelial dysfunction, as H 2 S is mainly derived from smooth muscle., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Introduction: Resveratrol (RVT) found in red wine protects against erectile dysfunction and relaxes penile tissue (corpus cavernosum) via a nitric oxide (NO) independent pathway. However, the mechanism remains to be elucidated. Hydrogen sulfide (H2 S) is a potent vasodilator and neuromodulator generated in corpus cavernosum., Aims: We investigated whether RVT caused the relaxation of mice corpus cavernosum (MCC) through H2 S., Methods: H2 S formation is measured by methylene blue assay and vascular reactivity experiments have been performed by DMT strip myograph in CD1 MCC strips., Main Outcome Measures: Endothelial NO synthase (eNOS) inhibitor Nω-Nitro-L-arginine (L-NNA, 0.1 mM) or H2 S inhibitor aminooxyacetic acid (AOAA, 2 mM) which inhibits both cystathionine-β-synthase (CBS) and cystathionine-gamma-lyase (CSE) enzyme or combination of AOAA with PAG (CSE inhibitor) has been used in the presence/absence of RVT (0.1 mM, 30 min) to elucidate the role of NO or H2 S pathways on the effects of RVT in MCC. Concentration-dependent relaxations to RVT, L-cysteine, sodium hydrogen sulfide (NaHS) and acetylcholine (ACh) were studied., Results: Exposure of murine corpus cavernosum to RVT increased both basal and L-cysteine-stimulated H2 S formation. Both of these effects were reversed by AOAA but not by L-NNA. RVT caused concentration-dependent relaxation of MCC and that RVT-induced relaxation was significantly inhibited by AOAA or AOAA + PAG but not by L-NNA. L-cysteine caused concentration-dependent relaxations, which are inhibited by AOAA or AOAA + PAG significantly. Incubation of MCC with RVT significantly increased L-cysteine-induced relaxation, and this effect was inhibited by AOAA + PAG. However, RVT did not alter the effect of exogenous H2 S (NaHS) or ACh-induced relaxations., Conclusions: These results demonstrate that RVT-induced relaxation is at least partly dependent on H2 S formation and acts independent of eNOS pathway. In phosphodiesterase 5 inhibitor (PDE-5i) nonresponder population, combination therapy with RVT may reverse erectile dysfunction via stimulating endogenous H2 S formation., (© 2015 International Society for Sexual Medicine.)