The metabolism and significance of homocysteine in nutrition and health.

An association between arteriosclerosis and homocysteine (Hcy) was first demonstrated in 1969. Hcy is a sulfur containing amino acid derived from the essential amino acid methionine (Met). Hyperhomocysteinemia (HHcy) was subsequently shown in several age-related pathologies such as osteoporosis, Alzheimer's disease, Parkinson's disease, stroke, and cardiovascular disease (CVD). Also, Hcy is associated with (but not limited to) cancer, aortic aneurysm, hypothyroidism and end renal stage disease to mention some. The circulating levels of Hcy can be increased by defects in enzymes of the metabolism of Met, deficiencies of vitamins B6, B12 and folate or by feeding Met enriched diets. Additionally, some of the pharmaceuticals currently in clinical practice such as lipid lowering, and anti-Parkinsonian drugs are known to elevate Hcy levels. Studies on supplementation with folate, vitamins B6 and B12 have shown reduction in Hcy levels but concomitant reduction in certain associated pathologies have not been definitive. The enormous importance of Hcy in health and disease is illustrated by its prevalence in the medical literature (e.g. > 22,000 publications). Although there are compelling data in favor of Hcy as a modifiable risk factor, the debate regarding the significance of Hcy mediated health effects is still ongoing. Despite associations between increased levels of Hcy with several pathologies being well documented, whether it is a causative factor, or an effect remains inconclusive. The present review though not exhaustive, is focused on several important aspects of Hcy metabolism and their relevance to health.

The impact of statins on biological characteristics of stem cells provides a novel explanation for their pleiotropic beneficial and adverse clinical effects.

Statins reduce atherosclerotic events and cardiovascular mortality. Their side effects include memory loss, myopathy, cataract formation, and increased risk of diabetes. As cardiovascular mortality relates to plaque instability, which depends on the integrity of the fibrous cap, we hypothesize that the inhibition of the potential of mesenchymal stem cells (MSCs) to differentiate into macrophages would help to explain the long known, but less understood "non-lipid-associated" or pleiotropic benefit of statins on cardiovascular mortality. In the present investigation, MSCs were treated with atorvastatin or pravastatin at clinically relevant concentrations and their proliferation, differentiation potential, and gene expression profile were assessed. Both types of statins reduced the overall growth rate of MSCs. Especially, statins reduced the potential of MSCs to differentiate into macrophages while they exhibited no direct effect on macrophage function. These findings suggest that the limited capacity of MSCs to differentiate into macrophages could possibly result in decreased macrophage density within the arterial plaque, reduced inflammation, and subsequently enhance plaque stability. This would explain the non-lipid-associated reduction in cardiovascular events. On a negative side, statins impaired the osteogenic and chondrogenic differentiation potential of MSCs and increased cell senescence and apoptosis, as indicated by upregulation of p16, p53 and Caspase 3, 8, and 9. Statins also impaired the expression of DNA repair genes, including XRCC4, XRCC6, and Apex1. While the effect on macrophage differentiation explains the beneficial side of statins, their impact on other biologic properties of stem cells provides a novel explanation for their adverse clinical effects.

Analysis of cardiovascular responses to the H2S donors Na2S and NaHS in the rat.

Hydrogen sulfide (H2S) is an endogenous gaseous molecule formed from L-cysteine in vascular tissue. In the present study, cardiovascular responses to the H2S donors Na2S and NaHS were investigated in the anesthetized rat. The intravenous injections of Na2S and NaHS 0.03-0.5 mg/kg produced dose-related decreases in systemic arterial pressure and heart rate, and at higher doses decreases in cardiac output, pulmonary arterial pressure, and systemic vascular resistance. H2S infusion studies show that decreases in systemic arterial pressure, heart rate, cardiac output, and systemic vascular resistance are well-maintained, and responses to Na2S are reversible. Decreases in heart rate were not blocked by atropine, suggesting that the bradycardia was independent of parasympathetic activation and was mediated by an effect on the sinus node. The decreases in systemic arterial pressure were not attenuated by hexamethonium, glybenclamide, N(w)-nitro-L-arginine methyl ester hydrochloride, sodium meclofenamate, ODQ, miconazole, 5-hydroxydecanoate, or tetraethylammonium, suggesting that ATP-sensitive potassium channels, nitric oxide, arachidonic acid metabolites, cyclic GMP, p450 epoxygenase metabolites, or large conductance calcium-activated potassium channels are not involved in mediating hypotensive responses to the H2S donors in the rat and that responses are not centrally mediated. The present data indicate that decreases in systemic arterial pressure in response to the H2S donors can be mediated by decreases in vascular resistance and cardiac output and that the donors have an effect on the sinus node independent of the parasympathetic system. The present data indicate that the mechanism of the peripherally mediated hypotensive response to the H2S donors is uncertain in the intact rat.

Intratunical Injection of Genetically Modified Adipose Tissue-Derived Stem Cells with Human Interferon α-2b for Treatment of Erectile Dysfunction in a Rat Model of Tunica Albugineal Fibrosis.

INTRODUCTION: Peyronie's disease (PD) has frequently been associated with erectile dysfunction (ED) and may further compromise coitus. AIM: To investigate the efficacy of intratunical injection of genetically modified rat adipose tissue-derived stem cells (ADSCs) expressing human interferon α-2b (ADSCs-IFN) in decreasing fibrosis and restoring erectile function in a rat model of tunica albugineal fibrosis (TAF). METHODS: A total of 36 Sprague-Dawley rats (12 weeks old; 300-350 g) were randomly divided in six equal groups: (i) sham group (50 µL saline-injected into the tunica albuginea [TA]); (ii) TAF group (transforming growth factor [TGF]-ß1 [0.5 µg/50 µL] injected into the TA); (iii) TGF-ß1 plus 5 × 10(5) control ADSCs injected same day; (iv) TGF-ß1 plus 5 × 10(5) ADSCs-IFN injected same day; (v) TGF-ß1 plus 5 × 10(5) control ADSCs injected after 30 days; and (vi) TGF-ß1 plus 5 × 10(5) ADSCs-IFN injected after 30 days. Rat allogeneic ADSCs were harvested from inguinal fat tissue. MAIN OUTCOME MEASURES: Forty-five days following the TGF-ß1 injection, erectile function was assessed, and penile tissues were harvested for further evaluations. RESULTS: In the same-day injection groups, intratunical injection of ADSCs and ADSC-IFN improved erectile response observed upon stimulation of cavernous nerve compared with TAF group. Intratunical ADSC-IFN injection at day 30 improved erectile responses 3.1, 1.8, and 1.3 fold at voltages of 2.5, 5.0, and 7.0, respectively, when compared with TAF group. Furthermore, at voltages of 2.5 and 5.0, treatment on day 30 with ADSCs-IFN improved erectile responses 1.6- and 1.3-fold over treatment with ADSCs alone. Local injection of ADSCs or ADSCs-IFN reduced Peyronie's-like manifestations, and these effects might be associated with a decrease in the expression of tissue inhibitors of metalloproteinases. CONCLUSION: This study documents that transplantation of genetically modified ADSCs, with or without human IFN α-2b, attenuated Peyronie's-like changes and enhanced erectile function in a rat model of TAF.

2015 update of erectile dysfunction management following radical prostatectomy: from basic research to clinical management.

Radical prostatectomy (RP) is the most commonly employed curative intervention for the treatment of prostate cancer. However, due to the proximity of the cavernous nerves (CN) to the prostate, RP results in transient and/often permanent erectile dysfunction (ED). While the prevention of traction injuries during the RP is critical for the preservation of erectile function, several preclinical studies have demonstrated the beneficial effects of neuroprotective (or neuroregenerative) agents in mitigating neuronal injuries sustained during RP. The maintenance or restoration of erectile function after injury may be enhanced in the postoperative period by the stimulation of neurogenesis to protect and restore injured nerves from further deterioration. The present review aims to evaluate and summarize research of these treatment strategies as published in the National Library of Medicine (Pubmed) from 2000 to 2015. The keywords used for the search were ED, RP, CN injury, immunophilin ligands, neurotrophins and phosphodiesterase (PDE)5 inhibitors, and animal models. Current guidelines for treatment targeting CN recovery recommend the use of immunophilin ligands, neurotrophins, brain-derived neurotrophic factor, glial cell-line derived neurotrophic factor, sonic hedgehog (Shh), Rho-kinase, PDE5 inhibitors, erythropoietin (EPO), hyperbaric oxygen, gene, stem cells, and triiodothyronine (T3) therapy. Additionally, this review identifies remaining gaps in general knowledge and recent updates recognizing the need for further preclinical and clinical trials.

Efficacy of pioglitazone on erectile function recovery in a rat model of cavernous nerve injury.

OBJECTIVE: To examine the effect of pioglitazone on erectile function in a rat model of postprostatectomy erectile dysfunction. METHODS: Twenty adult rats were divided into 4 groups: (a) sham, (b) control--bilateral cavernosal nerve crush injury (BCNI), (c) BCNI + low-dose pioglitazone (PioL), and (d) BCNI + high-dose pioglitazone (PioH). Sham and control rats were administered phosphate-buffered saline, whereas PioL and PioH rats received 0.65 and 6.5 mg/kg of pioglitazone, respectively. All treatments were administered by oral gavage for 14 days. After treatment, animals underwent surgery for endpoint cavernosal response to define hemodynamic parameters of erectile function, reported as the ratio of intracavernosal pressure to mean arterial pressure. Corporal tissue was retrieved for histologic and molecular analysis. RESULTS: Animals treated with pioglitazone experienced dose-dependent improvements in the ratio of intracavernosal pressure to mean arterial pressure, with the PioH group achieving results similar to the sham group: sham, 0.774; BCNI, 0.421; PioL, 0.616; PioH, 0.758 (P = .0006). PioH animals demonstrated increased expression of endothelial nitric oxide (eNOS) and neuronal nitric oxide (nNOS), whereas both PioL and PioH animals had increased staining for anti--smooth muscle actin antibody and nonsignificant increases in cyclic guanosine monophosphate (cGMP). CONCLUSION: Pioglitazone improves erectile function in rats undergoing BCNI via a nitric oxide--mediated pathway.

Intratracheal administration of cyclooxygenase-1-transduced adipose tissue-derived stem cells ameliorates monocrotaline-induced pulmonary hypertension in rats.

The effect of intratracheal administration of cyclooxygenase-1 (COX-1)-modified adipose stem cells (ASCs) on monocrotaline-induced pulmonary hypertension (MCT-PH) was investigated in the rat. The COX-1 gene was cloned from rat intestinal cells, fused with a hemagglutanin (HA) tag, and cloned into a lentiviral vector. The COX-1 lentiviral vector was shown to enhance COX-1 protein expression and inhibit proliferation of vascular smooth muscle cells without increasing apoptosis. Human ASCs transfected with the COX-1 lentiviral vector (ASCCOX-1) display enhanced COX-1 activity while exhibiting similar differentiation potential compared with untransduced (native) ASCs. PH was induced in rats with MCT, and the rats were subsequently treated with intratracheal injection of ASCCOX-1 or untransduced ASCs. The intratracheal administration of ASCCOX-1 3 × 10(6) cells on day 14 after MCT treatment significantly attenuated MCT-induced PH when hemodynamic values were measured on day 35 after MCT treatment whereas administration of untransduced ASCs had no significant effect. These results indicate that intratracheally administered ASCCOX-1 persisted for at least 21 days in the lung and attenuate MCT-induced PH and right ventricular hypertrophy. In addition, vasodilator responses to the nitric oxide donor sodium nitroprusside were not altered by the presence of ASCCOX-1 in the lung. These data emphasize the effectiveness of ASCCOX-1 in the treatment of experimentally induced PH.

Mechanism of endoplasmic reticulum stress-induced vascular endothelial dysfunction.

BACKGROUND: We recently reported that ER stress plays a key role in vascular endothelial dysfunction during hypertension. In this study we aimed to elucidate the mechanisms by which ER stress induction and oxidative stress impair vascular endothelial function. METHODOLOGY/PRINCIPAL FINDINGS: We conducted in vitro studies with primary endothelial cells from coronary arteries stimulated with tunicamycin, 1µg/mL, in the presence or absence of two ER stress inhibitors: tauroursodeoxycholic acid (Tudca), 500µg/mL, and 4-phenylbutyric acid (PBA), 5mM. ER stress induction was assessed by enhanced phosphorylation of PERK and eIF2α, and increased expression of CHOP, ATF6 and Grp78/Bip. The ER stress induction increased p38 MAPK phosphorylation, Nox2/4 mRNA levels and NADPH oxidase activity, and decreased eNOS promoter activity, eNOS expression and phosphorylation, and nitrite levels. Interestingly, the inhibition of p38 MAPK pathway reduced CHOP and Bip expressions enhanced by tunicamycin and restored eNOS promoter activation as well as phosphorylation. To study the effects of ER stress induction in vivo, we used C57BL/6J mice and p47phox(-/-) mice injected with tunicamycin or saline. The ER stress induction in mice significantly impaired vascular endothelium-dependent and independent relaxation in C57BL/6J mice compared with p47phox(-/-) mice indicating NADPH oxidase activity as an intermediate for ER stress in vascular endothelial dysfunction. CONCLUSION/SIGNIFICANCE: We conclude that chemically induced ER stress leads to a downstream enhancement of p38 MAPK and oxidative stress causing vascular endothelial dysfunction. Our results indicate that inhibition of ER stress could be a novel therapeutic strategy to attenuate vascular dysfunction during cardiovascular diseases.

Angina pectoris: current therapy and future treatment options.

Angina pectoris is the consequence of an inequality between the demand and supply of blood to the heart. Angina manifests itself as chest pain or discomfort and is a common complaint of patients in the hospital and in the clinic. There are, in fact, roughly half a million new cases of angina per year. Chest pain, while having many etiologies, is generally considered to be most lethal when related to a cardiac cause. In this review, the authors outline the current medical and surgical therapies that are used in the management of angina. Highlights of the various clinical trials that have assisted in the investigation of these therapies are summarized also. Then, the authors provide a focused review of the novel therapy options for angina that are currently being explored. From new medical treatments to revised surgical techniques to the discovery of stem cell therapy, many innovative options are being investigated for the treatment of angina.

Imatinib mesylate (Gleevec) induces human corpus cavernosum relaxation by inhibiting receptor tyrosine kinases (RTKs): identification of new RTK targets.

OBJECTIVE: To evaluate the effect of the tyrosine kinase inhibitor imatinib mesylate (Gleevec) on human corpus cavernosum (HCC) smooth muscle tone. METHODS: HCC were obtained from 18 erectile dysfunction (ED) patients undergoing penile prosthesis surgery. The effects of imatinib in HCC strips were investigated in the presence of various inhibitors. The human phosphoreceptor protein tyrosine kinase (PTK) array (Proteome Profiler Array) detected changes in receptor phosphorylation before and after imatinib. Immunohistochemistry was used to localize phosphorylated c-kit (CD117/stem cell factor) in HCC smooth muscle cells. RESULTS: Phenylephrine-induced contraction in HCC was significantly inhibited by imatinib (97.7% ± 2.3%). l-nitro-arginine methyl ester (l-NAME) or guanylyl cyclase inhibitor [1H-1,2,4] oxadiazolo [4,3-a]quinoxalin-1-one (ODQ) alone did not reverse the effect of imatinib, but suppressed this response in combination (18.0% ± 0.6%). The K(+) channel blockers (apamin and tetraethyl ammonium) decreased the imatinib-induced relaxation by 64% and 51%, respectively. PTK microarray analysis of 42 different phospho-receptor tyrosine kinases showed 14 were clearly activated in HCC. Imatinib treatment significantly inhibited phosphorylation of PTKs. A high level of CD117/c-kit-positive immunostaining was detected in untreated HCC smooth muscle, but not in treated HCC. CONCLUSION: Imatinib caused HCC smooth muscle relaxation in vitro mediated by nitric oxide/guanosine monophosphate signaling, involving the large-conductance Ca(2+)-activated K(+)-channels (BK(Ca)) or by inhibiting the upregulated PTK pathway. These results suggest that imatinib may also benefit erectile dysfunction patients who are not responsive to phosphodiesterase-5 inhibitors.

Effects of 5-alpha reductase inhibitors on erectile function, sexual desire and ejaculation.

INTRODUCTION: Treatment with 5-alpha reductase inhibitors (5ARI) is commonly utilized for the treatment of benign prostatic hyperplasia (BPH). The true prevalence of sexual side effects with 5ARI treatment is currently unknown. AREAS COVERED: The current article reviews the reported adverse effects of 5ARI in regard to erectile function, sexual desire and ejaculation. A PubMed search was performed of all articles from 1990 to present, which reported any sexual side effects with finasteride or dutasteride. Preference was given to more recent and human studies where available. EXPERT OPINION: Clinical trials with 5ARI report prevalence rates of de novo erectile dysfunction of 5 - 9%. Decreased circulating dihydrotestosterone (DHT) resulting from 5ARI use is associated with diminished sexual desire and/or orgasm. The presence of adverse sexual effects is associated with decreased self-esteem, quality of life and ability to maintain an intimate relationship. Inhibition of 5ARI additionally influences progesterone and deoxycorticosterone levels and may alter psychological functions, including increased depression, melancholy and loss of general well being. Ejaculatory dysfunction has not been well studied in patients using 5ARI. Patients receiving therapy with 5ARI should be counseled as to potential sexual and psychological adverse effects. Future clinical studies are needed to further investigate the sexual side effects associated with this class of drugs.

Adipose tissue-derived stem cell-seeded small intestinal submucosa for tunica albuginea grafting and reconstruction.

Porcine small intestinal submucosa (SIS) has been widely used in tunica albuginea (TA) reconstructive surgery. Adipose tissue-derived stem cells (ADSCs) can repair damaged tissue, augment cellular differentiation, and stimulate release of multiple growth factors. The aim of this rat study was to assess the feasibility of seeding ADSCs onto SIS grafts for TA reconstruction. Here, we demonstrate that seeding syngeneic ADSCs onto SIS grafts (SIS-ADSC) resulted in significant cavernosal tissue preservation and maintained erectile responses, similar to controls, in a rat model of bilateral incision of TA, compared with sham-operated animals and rats grafted with SIS graft (SIS) alone. In addition to increased TGF-ß1 and FGF-2 expression levels, cross-sectional studies of the rat penis with SIS and SIS-ADSC revealed mild to moderate fibrosis and an increase of 30% and 40% in mean diameter in flaccid and erectile states, respectively. SIS grafting induced transcriptional up-regulation of iNOS and down-regulation of endothelial NOS, neuronal NOS, and VEGF, an effect that was restored by seeding ADCSs on the SIS graft. Taken together, these data show that rats undergoing TA incision with autologous SIS-ADSC grafts maintained better erectile function compared with animals grafted with SIS alone. This study suggests that SIS-ADSC grafting can be successfully used for TA reconstruction procedures and can restore erectile function.

Inhibition of sympathetic neuroeffector transmission in human corpus cavernosum.

UNLABELLED: What's known on the subject? and What does the study add? In the present study the mechanisms regulating EFS-evoked neurogenic contraction in the human corpus cavernosum (HCC) were investigated. Overall, our data adds to current knowledge that the NO-independent heme dependent activation of sGC and the RhoA/Rho-kinase signaling pathways play an important role in the regulation of neurogenic contractile activity in HCC tissue. OBJECTIVE: To investigate the mechanisms of adrenergically mediated smooth muscle contraction in the human corpus cavernosum (HCC) using an organ bath approach. METHODS: Human corpus cavernosum specimens were obtained from patients (aged 59-72 years) with erectile dysfunction (ED), undergoing penile prosthesis implantation surgery. Isolated HCC strips (1 × 1 × 6 mm) were suspended in tissue bath chambers for isometric tension recording. The effects of various drugs on neurogenic contractions evoked by electrical field stimulation (EFS) were investigated. The drugs included nitric oxide (NO) donors, phosphodiesterase 5 (PDE5) inhibitor, Rho kinase (ROCK) inhibitor, NO-independent stimulator, L-type Ca2+ channel blocker and α-receptor antagonist. RESULTS: Pre-incubation with the NO donor sodium nitroprusside (SNP; 10(4) M) significantly reduced the initial peak increase in tension evoked by EFS (by 71%, P < 0.05). The PDE5 inhibitor sildenafil (10(-4) M) reduced the increase in tension by 69%, while a combination of sildenafil and ROCK inhibitor, fasudil, inhibited tension by 81%. The EFS-induced contractile response at 80 Hz was decreased by 65% with fasudil and by 70% with isradipine (P < 0.001), while a combination of these drugs decreased the response by 88%. An NO-independent stimulator soluble guanylate cyclase (sGC), BAY 41-8543, significantly reduced the response (by 82%, P < 0.001) Phentolamine, an α-receptor antagonist, nearly eliminated the contractile response (98%, P < 0.001). CONCLUSIONS: These data suggest that neurogenic contractions are mediated by an increase in Ca(2+) influx via L-type voltage-gated Ca(2+) channels and that an increase in Ca(2+) sensitivity is mediated by the ROCK pathway and the PDE5 enzyme system as well as by the inhibitory NO/sGC/cGMP pathway. The neurogenic contractile response in HCC is mediated by several intracellular pathways, including adrenergic receptors, Ca(2+) entry, Ca(2+) sensitization and activation of the PDE5 enzyme. The Rho-kinase (ROCK) inhibitor fasudil, L-type Ca(2+) channel antagonist isradipine, and PDE5 inhibitor sildenafil, as well as a NO-independent stimulator of sGC, had similar inhibitory effects, suggesting parallel mechanisms in the HCC.

Aging alters tissue resident mesenchymal stem cell properties.

Tissue resident mesenchymal stem cells (MSCs) are known to participate in tissue regeneration that follows cell turnover, apoptosis, or necrosis. It has been long known that aging impedes an organism's repair/regeneration capabilities. In order to study the age associated changes, the molecular characteristics of adipose tissue derived MSCs (ASCs) from three age groups of healthy volunteers, i.e., young, middle aged, and aged were investigated. The number and multilineage differentiation potential of ASCs declined with age. Aging reduces the proliferative capacity along with increases in cellular senescence. A significant increase in quiescence of G2 and S phase was observed in ASCs from aged donors. The expression of genes related to senescence such as CHEK1 and cyclin-dependent kinase inhibitor p16(ink4a) was increased with age, however genes of apoptosis were downregulated. Further, an age-dependent abnormality in the expression of DNA break repair genes was observed. Global microRNA analysis revealed an abnormal expression of mir-27b, mir-106a, mir-199a, and let-7. In ubiquitously distributed adipose tissue (and ASCs), aging brings about important alterations, which might be critical for tissue regeneration and homeostasis. Our findings therefore provide a better understanding of the mechanism(s) involved in stem cell aging and regenerative potential, and this in turn may affect tissue repair that declines with aging.

Drugs of the future for Peyronie's disease.

With the increasing awareness of Peyronie's disease (PD), the interest in new concept medications to treat the disorder is escalating. Profibrogenic factors such as transforming growth factor (TGF)-beta1, endothelin (ET-1), connective tissue growth factor (CTGF), angiotensin (Ang) II and platelet derived growth factor (PDGF), all appear to be involved in the pathogenesis of PD. ß-Thymosins, pirfenidone, nitric oxide (NO) donors, phosphodiesterase (PDE)-5 inhibitors, matrix metalloproteinases (MMPs)/anti-tissue inhibitor of metalloproteinases (TIMP)-1 reduce collagen synthesis, while decorin, follistatin, and Smad 7 exert antifibrotic effects; all have been proposed for the treatment of PD. Alternative and/or novel approaches for the treatment of PD are needed in part because of the recognized multifactorial etiology of this complex disorder. A comprehensive approach for translating available experimental information into clinically effective drug trials for the treatment of PD is needed. We propose a multi-faceted approach for drug development to generate novel drug products for the treatment of PD.

RhoA/Rho-kinase as a therapeutic target for the male urogenital tract.

INTRODUCTION: Rho-kinase (ROCK) is a serine/threonine kinase and is one of the major downstream effectors of the small guanosine triphosphatase Rho. In the past few years, evidence has been accumulating to suggest that the RhoA/ROCK system may play an important role in the pathogenesis of a number of cardiovascular and urogenital disorders. AIM: The aim of this study is to review the literature pertaining to the role of the RhoA/ROCK system in male urogenital function. METHODS: Comprehensive literature review was performed using PubMed. MAIN OUTCOME MEASURES: Inhibitors of ROCK may have potential therapeutic applications, as derived from preclinical and a few clinical studies. RESULTS: Published reports suggest that elevated RhoA/Rho-kinase signaling plays a role in the development of benign prostatic hyperplasia, erectile dysfunction, kidney failure, ejaculation disorders, prostate and bladder cancer initiation, and eventual metastasis. CONCLUSIONS: This review focuses on our current understanding of the role of the RhoA/Rho-kinase pathway in the regulation of the male urogenital system. Rho-kinase inhibitors may evolve into an important pharmacologic option in the future treatment of urogenital system disorders.

Role of nitric oxide in developmental biology in plants, bacteria, and man.

Since its discovery, nitric oxide (NO) has been observed to play an important role in the physiology of single-celled organisms as well as high-order vertebrates. In this review, we will discuss the involvement of NO in bacterial, plant and human systems. NO originates from a variety of sources, namely bacterial, plant, and mammalian nitric oxide synthases which oxidize L-arginine. Bacterial NO is involved in toxin synthesis, signaling and biofilm formation. Organisms use NO to mediate oxidative stress incurred during the innate immune response. In plants, large amounts of NO hinder plant growth, while lower concentrations regulate normal development. NO and the associated reactive oxygen species (ROS) are effective antibacterial, anti-parasitic, and antifungal agents. Though NO has therapeutic effects in the immune system, the NO response is biphasic and concentration-dependent. NO promotes tumorigenesis within a concentration range, and induces apoptosis of cancerous cells at other concentrations. The biphasic response to NO is also evident in the regulation of chemokine, interleukins, and NF-κB, which can promote or inhibit inflammation. The physiologic response to NO is concentration dependent. NO, by way of non-adrenergic noncholinergic (NANC) nerve transmission, propagates a cascade of molecular signaling that facilitates smooth muscle cell relaxation and increased arterial inflow into the corpora, initiating an erectile response. Additional NO is released through NOS activity in the endothelium in response to cholinergic nerve activity and shear stress, which helps to maintain erection.

Effects of salsalate therapy on recovery from vascular injury in female Zucker fatty rats.

OBJECTIVE: Salsalate is a dimeric form of salicylic acid that has been shown to have anti-inflammatory activity and to reduce glucose levels, insulin resistance, and cytokine expression. However, the effect of salsalate on vascular injury has not been determined. The objective of this study is to investigate the effect of salsalate on vascular injury and repair in a rat model of carotid artery balloon catheter injury. RESEARCH DESIGN AND METHODS: Salsalate treatment was started in female Zucker fatty rats (insulin resistant) 1 week before carotid artery balloon catheter injury and continued for 21 days, at which time the animals were killed and studied. RESULTS: Treatment with salsalate significantly decreased the intima-to-media ratio and upregulated the expression of aortic endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS) (ser 1177), and manganese superoxide dismutase (MnSOD) and reduced serum interleukin (IL)-6 with concomitant downregulation of nuclear factor (NF) κB subunit p65 and vascular endothelial growth factor (VEGF) expression in the balloon-injured carotid artery of female Zucker fatty rats. CONCLUSIONS: The present study shows that salsalate treatment decreases vascular damage caused by balloon catheter injury in female Zucker fatty rats. The beneficial effect of salsalate on vascular injury was associated with upregulation of eNOS, p-eNOS, and MnSOD, which reduce oxidative stress and have anti-inflammatory properties, as evidenced by reduction in serum IL-6 and the downregulation of VEGF and NFκB, which promote inflammation without changing glucose levels. These results suggest that salsalate may be useful in reducing vascular injury and restenosis following interventional revascularization procedures.

Intracavernosal administration of sodium nitrite as an erectile pharmacotherapy.

It has been reported that sodium nitrite (NaNO2) can act as a storage form of nitric oxide (NO) that can have beneficial pharmacologic actions. The present study was undertaken to investigate the effects of NaNO2 on erectile function in the rat. The intracavernosal (i.c.) injection of NaNO2 produced dose-related increases in i.c. pressure and decreases in systemic arterial pressure. NaNO2 was 1000-fold less potent than sodium nitroprusside in increasing i.c. pressure. Increases in i.c. pressure in response to NaNO2 were attenuated by the nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine methyl ester (L-NAME). The increases in i.c. pressure in response to NaNO2 were not altered by the xanthine oxidoreductase inhibitor allopurinol. The decreases in systemic arterial pressure in response to i.c. injections of NaNO2 were attenuated by allopurinol and were either unchanged or increased by L-NAME. These data suggest that NaNO2 is converted to vasoactive NO in the corpora cavernosum and systemic vascular bed of the rat by different mechanisms. The present data suggest that the conversion of NaNO2 to vasoactive NO is mediated by NOS in the corpora cavernosum and by xanthine oxidoreductase in the systemic vascular bed of the rat. These data show NaNO2 can serve as a NO donor that increases erectile activity in the rat.

Modified multipotent stromal cells with epidermal growth factor restore vasculogenesis and blood flow in ischemic hind-limb of type II diabetic mice.

Diabetes is increasing in the world and causes severe cardiovascular complications. Diabetes-induced limb ischemia leads to foot amputation and therapeutic remedies are urgently needed. Here we report that local injection of mesenchymal stem cells (MSCs) prestimulated with epidermal growth factor (EGF) restored blood flow and vasculogenesis in the ischemic hind-limb of type II diabetic (db(-)/db(-)) mice. Bone marrow cells from db(-)/db(-) mice are altered as evidenced by increased oxidative stress and reduced Akt and adhesion molecules when compared with control (db(-)/db(+)). Femoral artery ligation-induced ischemia was performed in the hind-limb of db(-)/db(-) and db(-)/db(+) mice for 28 days. Enhanced green fluorescent protein (EGFP)-MSCs stimulated+/-exogenous EGF for 24 h were injected locally into the ischemic muscle. Blood flow measured with MoorLDI-Laser and microangiography assessed with X-ray showed 100% recovery in db(-)/db(+) compared to 50% recovery in db(-)/db(-) mice. Interestingly, db(-)/db(-) mice had 60 and 96% blood flow recovery and 61 and 98% of vasculogenesis when treated with MSCs alone or MSCs modified with EGF, respectively. Western blot analysis of hind-limb muscles revealed an increase in Akt and vascular endothelial growth factor receptor phosphorylation and hypoxia-inducible factor) expression in db(-)/db(-) mice injected with MSCs or MSCs+EGF compared to db(-)/db(-) mice. Fluorescent microscopic images show that EGFP-MSCs differentiate into new microvessels. Adhesion and migration of MSCs on cultured endothelial cells were ICAM1-, VCAM1- and Akt-dependent mechanism and elevated when MSCs were prestimulated with EGF compared with nonstimulated MSCs. Our novel study data provide evidence that in type II diabetes, stimulated MSCs with EGF enhance the recovery of blood flow and angiogenesis.