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Background: Erectile dysfunction is a condition with a rapidly increasing prevalence globally with a strong correlation to the increase in obesity and cardiovascular disease rates., Aim: The aim of the current study is to investigate the potential role of tubacin, a histone deacetylase 6 (HDAC6) inhibitor, in restoring erectile function in a hypercholesterolemia-induced endothelial dysfunction model., Methods: Thirty-nine male C57Bl/6 J mice were divided into 3 groups. Two groups were administered an adeno-associated virus encoding for the gain of function of proprotein convertase subtilisin/kexin type 9 (PCSK9) and placed on a high-fat diet (HFD) with 1.25% cholesterol added for 18 weeks in order to induce a prolonged state of hypercholesterolemia. One of the PCSK9 groups received daily intraperitoneal injections of the HDAC6 inhibitor tubacin, while the other 2 groups received daily vehicle injections. Erectile function was assessed through measurement of intracavernosal pressure and mean arterial pressure during cavernous nerve stimulation, as well as assessment of agonist-stimulated ex vivo relaxation of the corpus cavernosum (CC). Western blotting was performed from CC tissue samples., Outcomes: Erectile and endothelial functions were assessed, as well as protein markers of mitochondrial dynamics, mitophagy, and autophagy., Results: Erectile function was impaired in the HFD + PCSK9 group throughout the entire voltage range of stimulation. However, the HFD + PCSK9 mice that were treated with tubacin experienced significant restoration of erectile function at the medium and high voltages of nerve stimulation. Similarly, ex vivo CC relaxation responses to acetylcholine and the cystathionine γ-lyase (CSE) substrate L-cysteine were reduced in the vehicle-treated HFD + PCSK9 mice, both of which were restored in the HFD + PCSK9 mice treated with tubacin. Corpus-cavernosum protein expression of CSE was significantly elevated in the tubacin-treated HFD + PCSK9 mice relative to both other groups. There were no significant differences observed in any of the protein markers of mitochondrial dynamics, mitophagy, or autophagy investigated., Clinical Translation: Histone deacetylase 6 inhibition may protect against erectile and endothelial dysfunction associated with hypercholesterolemia., Strengths and Limitations: This was the first study to investigate HDAC6-specific inhibition for treatment of erectile dysfunction. A study limitation was the exclusive focus on the CC, rather than structure and function of the pre-penile arteries that may develop a substantial atherosclerotic plaque burden under hypercholesterolemic conditions., Conclusions: Tubacin may prevent hypercholesterolemia-induced erectile dysfunction through a hydrogen sulfide-related mechanism unrelated to regulation of mitophagy or autophagy., Competing Interests: None declared., (© The Author(s) 2025. Published by Oxford University Press on behalf of The International Society for Sexual Medicine.)

Introduction: Cigarette smoke (CS) invokes an inflammatory response associated with vascular dysfunction and atherosclerosis. The role of sex and nicotine in CS effects on cardiovascular function and atherosclerosis is unexplored., Methods: Male and female C57Bl/6 WT (wild type) and ApoE-/- mice were exposed to CS and nicotine with access to chow and water ad libitum for 16 weeks to fill this gap. Heart rate and endothelial function were measured in the aorta of WT mice, while the lipid profile, cytokines, chemokines, and plaque area and composition were assessed in ApoE-/- mice., Results: CS increased heart rate similarly in both sexes and induced a more substantial impairment in endothelial function in males and more plaque in females than nicotine. Necrotic core areas were similar for both treatments in both sexes, while females had higher collagen deposition across treatments. Both treatments elevated senescence-associated GLB1/-galactosidase (SA-GLB1) and interleukin 17A (IL17A) similarly in both sexes. CS upregulated cholesterol in both sexes, triglycerides, VLDL, HDL, and C-X-C motif chemokine ligand-5 (CXCL5/LIX) only in males, and LDL and IL1A only in females. Additionally, nicotine metabolism showed sex-specific responses to nicotine but not smoking., Conclusion: Findings suggest sex influences cardiovascular function and atherosclerosis following exposure to nicotine and CS., Implications: The purpose of this study was to fill the existing literature gap through assessment of the differential sex effects of CS and nicotine on vascular function and atherosclerosis to identify sex-specific risk factors. We show sex-specific differences in endothelial function, plaque, inflammation, and extracellular matrix (ECM) regulators with exposure to CS and nicotine, which underscore the importance of assessing sex in tobacco and nicotine exposure studies. This study also shows the negative effect of oral nicotine administration as many oral dissolvable nicotine products, like pouches and gum, are becoming increasingly popular among adolescents and young adults., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

There has been growing interest within the space industry for long-duration manned expeditions to the Moon and Mars. During deep space missions, astronauts are exposed to high levels of galactic cosmic radiation (GCR) and microgravity which are associated with increased risk of oxidative stress and endothelial dysfunction. Oxidative stress and endothelial dysfunction are causative factors in the pathogenesis of erectile dysfunction, although the effects of spaceflight on erectile function have been unexplored. Therefore, the purpose of this study was to investigate the effects of simulated spaceflight and long-term recovery on tissues critical for erectile function, the distal internal pudendal artery (dIPA), and the corpus cavernosum (CC). Eighty-six adult male Fisher-344 rats were randomized into six groups and exposed to 4-weeks of hindlimb unloading (HLU) or weight-bearing control, and sham (0Gy), 0.75 Gy, or 1.5 Gy of simulated GCR at the ground-based GCR simulator at the NASA Space Radiation Laboratory. Following a 12-13-month recovery, ex vivo physiological analysis of the dIPA and CC tissue segments revealed differential impacts of HLU and GCR on endothelium-dependent and -independent relaxation that was tissue type specific. GCR impaired non-adrenergic non-cholinergic (NANC) nerve-mediated relaxation in the dIPA and CC, while follow-up experiments of the CC showed restoration of NANC-mediated relaxation of GCR tissues following acute incubation with the antioxidants mito-TEMPO and TEMPOL, as well as inhibitors of xanthine oxidase and arginase. These findings indicate that simulated spaceflight exerts a long-term impairment of neurovascular erectile function, which exposes a new health risk to consider with deep space exploration., (© 2023 Federation of American Societies for Experimental Biology.)

Aims: Erectile dysfunction is a common complication within many pathological conditions associated with low testosterone. Testosterone deficiency increases oxidative stress in the penile tissue that contributes to endothelial dysfunction and subsequent erectile dysfunction. Current therapies do not ameliorate oxidative stress so targeting oxidative stress may improve erectile dysfunction. Resveratrol and MitoQ are two prospective drugs that have antioxidant-like properties and may be useful to improve erectile dysfunction induced by androgen deprivation., Materials and Methods: We castrated 12-week-old male C57BL/6 mice and performed an eight-week intervention with oral delivery of resveratrol or MitoQ at low and high doses. We assessed vascular reactivity of the corpus cavernosum and internal pudendal arteries (IPA) through dose-dependent responses to vasodilatory, vasocontractile, and neurogenic stimuli in a myograph system. We performed qRT-PCR to measure expression changes of 18 antioxidant genes in the corpus cavernosum., Key Findings: Castration significantly impaired erectile function via impaired endothelial-dependent and-independent relaxation, and increased constriction of the corpus cavernosum, and induced severe endothelial dysfunction of the IPA. Castration decreased expression of 8 of the antioxidant genes investigated. Resveratrol and MitoQ were ineffective in reversing the effects of androgen deprivation on vascular reactivity, however high-dose resveratrol treatment upregulated several key antioxidant genes, including Cat, Sod1, Gstm1, and Prdx3., Significance: Our findings suggest that oral resveratrol and MitoQ treatment may provide protection to the corpus cavernosum under androgen deprived conditions by stimulating endogenous antioxidant systems. However, they may need to be paired with vasoactive drugs to reverse erectile dysfunction under androgen deprived conditions., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The mechanistic target of rapamycin (mTOR) is a nutrient-sensitive cellular signaling kinase that has been implicated in the excess production of reactive oxygen species (ROS). NADPH oxidase-derived ROS have been implicated in erectile dysfunction pathogenesis. The objective of this study was to determine if mTOR is an activator of NADPH oxidase in the penis and to determine the functional relevance of this pathway in a translationally relevant model of diet-induced erectile dysfunction. Male mice were fed a control diet or a high-fat, high-sucrose Western style diet (WD) for 12 weeks and treated with vehicle or rapamycin for the final 4 weeks of the dietary intervention. Following the intervention, erectile function was assessed by cavernous nerve-stimulated intracavernous pressure measurement, in vivo ROS production was measured in the penis using a microdialysis approach, and relative protein contents from the corpus cavernosum were determined by Western blot. Erectile function was impaired in vehicle treated WD-mice and was preserved in rapamycin treated WD-mice. Penile NADPH oxidase-mediated ROS were elevated in WD-mice and suppressed by rapamycin treatment. Western blot analysis suggests mTOR activation with WD by increased active site phosphorylation of mTOR and p70S6K, and increased expression of NADPH oxidase subunits, all of which were suppressed by rapamycin. These data suggest that mTOR is an upstream mediator of NADPH oxidase in the corpus cavernosum in response to a chronic Western diet, which has an adverse effect on erectile function.

Priapism, a prolonged penile erection in the absence of sexual arousal, is common among patients with sickle cell disease (SCD). Hypogonadism is also common in patients with SCD. While the administration of exogenous testosterone reverses hypogonadism, it is contraceptive. We hypothesized that the stimulation of endogenous testosterone production decreases priapism by normalizing molecular signaling involved in penile erection without decreasing intratesticular testosterone production, which would affect fertility. Treatment of SCD mice with FGIN-1-27, a ligand for translocator protein (TSPO) that mobilizes cholesterol to the inner mitochondrial membrane, resulted in eugonadal levels of serum testosterone without decreasing intratesticular testosterone production. Normalized testosterone levels, in turn, decreased priapism. At the molecular level, TSPO restored phosphodiesterase 5 activity and decreased NADPH oxidase-mediated oxidative stress in the penis, which are major molecular signaling molecules involved in penile erection and are dysregulated in SCD. These results indicate that pharmacologic activation of TSPO could be a novel, targetable pathway for treating hypogonadal men, particularly patients with SCD, without adverse effects on fertility., (© 2020 Wiley Periodicals LLC.)

NADPH oxidases (NOX) are enzyme complexes that have received much attention as key molecules in the development of vascular dysfunction. NOX have the primary function of generating reactive oxygen species (ROS), and are considered the main source of ROS production in endothelial cells. The endothelium is a thin monolayer that lines the inner surface of blood vessels, acting as a secretory organ to maintain homeostasis of blood flow. The enzymatic production of nitric oxide (NO) by endothelial NO synthase (eNOS) is critical in mediating endothelial function, and oxidative stress can cause dysregulation of eNOS and endothelial dysfunction. Insulin is a stimulus for increases in blood flow and endothelium-dependent vasodilation. However, cardiovascular disease and type 2 diabetes are characterized by poor control of the endothelial cell redox environment, with a shift toward overproduction of ROS by NOX. Studies in models of type 2 diabetes demonstrate that aberrant NOX activation contributes to uncoupling of eNOS and endothelial dysfunction. It is well-established that endothelial dysfunction precedes the onset of cardiovascular disease, therefore NOX are important molecular links between type 2 diabetes and vascular complications. The aim of the current review is to describe the normal, healthy physiological mechanisms involved in endothelial function, and highlight the central role of NOX in mediating endothelial dysfunction when glucose homeostasis is impaired.

Priapism is a disorder in which prolonged penile erection persists uncontrollably, potentially leading to tissue damage. Priapism commonly afflicts patient populations with severely low nitric oxide (NO) bioavailability. Because NO is a primary mediator of erection, the molecular mechanisms involved in priapism pathophysiology associated with low NO bioavailability are not well-understood. The objective of this study was to identify dysregulated molecular targets and signaling pathways in penile tissue of a mouse model of low NO bioavailability that have potential relevance to priapism. Neuronal plus endothelial NO synthase double knockout mice (NOS1/3 -/- ) were used as a model of low NO bioavailability. Priapic-like activity was demonstrated in the NOS1/3 -/- mice relative to wild-type (WT) mice by the measurement of prolonged erections following cessation of electrical stimulation of the cavernous nerve. Penile tissue was processed and analyzed by reverse-phase liquid chromatography tandem mass spectrometry. As a result, 1279 total proteins were identified and quantified by spectral counting, 46 of which were down-regulated and 110 of which were up-regulated in NOS1/3 -/- versus WT (P < 0.05). Ingenuity Pathway Analysis of differentially expressed proteins revealed increased protein kinase A and G-protein coupled receptor signaling in NOS1/3 -/- penises, which represent potential mechanisms contributing to priapism for secondary to low NO bioavailability.

Objectives: To evaluate neuronal nitric oxide (NO) synthase (nNOS) phosphorylation, nNOS uncoupling, and oxidative stress in the penis and major pelvic ganglia (MPG), before and after the administration of the cAMP-dependent protein kinase A (PKA) agonist colforsin in a rat model of bilateral cavernous nerve injury (BCNI),which mimics nerve injury after prostatectomy., Materials and Methods: Adult male Sprague-Dawley rats were divided into BCNI and sham-operated groups. Each group included two subgroups: vehicle and colforsin (0.1 mg/kg/day i.p.). After 3 days, erectile function (intracavernosal pressure) was measured and penis and MPG were collected for molecular analyses of phospho (P)-nNOS (Ser-1412 and Ser-847), total nNOS, nNOS uncoupling, binding of protein inhibitor of nNOS (PIN) to nNOS, gp91 phox subunit of NADPH oxidase, active caspase 3, PKA catalytic subunit α (PKA-Cα; by Western blot) and oxidative stress (hydrogen peroxide [H 2 O 2 ] and superoxide by Western blot and microdialysis method)., Results: Erectile function was decreased 3 days after BCNI and normalized by colforsin. nNOS phosphorylation on both positive (Ser-1412) and negative (Ser-847) regulatory sites, and nNOS uncoupling, were increased after BCNI in the penis and MPG, and normalized by colforsin. H 2 O 2 and total reactive oxygen species production were increased in the penis after BCNI and normalized by colforsin. Protein expression of gp91 phox was increased in the MPG after BCNI and was normalized by colforsin treatment. Binding of PIN to nNOS was increased in the penis after BCNI and was normalized by colforsin treatment. Protein expression of active Caspase 3 was increased in the MPG after BCNI and was normalized by colforsin treatment. Protein expression of PKA-Cα was decreased in the penis after BCNI and normalized by colforsin., Conclusion: Collectively, BCNI impairs nNOS function in the penis and MPG by mechanisms involving its phosphorylation and uncoupling in association with increased oxidative stress, resulting in erectile dysfunction. PKA activation by colforsin reverses these molecular changes and preserves penile erection in the face of BCNI., (© 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.)

Objective: The objectives of this study were to determine the impact of in vivo reactive oxygen species (ROS) on microvascular endothelial function in obese human subjects and the efficacy of an aerobic exercise intervention on alleviating obesity-associated dysfunctionality., Approach and Results: Young, sedentary men and women were divided into lean (body mass index 18-25; n=14), intermediate (body mass index 28-32.5; n=13), and obese (body mass index 33-40; n=15) groups. A novel microdialysis technique was utilized to detect elevated interstitial hydrogen peroxide (H 2 O 2 ) and superoxide levels in the vastus lateralis of obese compared with both lean and intermediate subjects. Nutritive blood flow was monitored in the vastus lateralis via the microdialysis-ethanol technique. A decrement in acetylcholine-stimulated blood flow revealed impaired microvascular endothelial function in the obese subjects. Perfusion of apocynin, an NADPH oxidase inhibitor, lowered (normalized) H 2 O 2 and superoxide levels, and reversed microvascular endothelial dysfunction in obese subjects. After 8 weeks of exercise, H 2 O 2 levels were decreased in the obese subjects and microvascular endothelial function in these subjects was restored to levels similar to lean subjects. Skeletal muscle protein expression of the NADPH oxidase subunits p22 phox , p47 phox , and p67 phox was increased in obese relative to lean subjects, where p22 phox and p67 phox expression was attenuated by exercise training in obese subjects., Conclusions: This study implicates NADPH oxidase as a source of excessive ROS production in skeletal muscle of obese individuals and links excessive NADPH oxidase-derived ROS to microvascular endothelial dysfunction in obesity. Furthermore, aerobic exercise training proved to be an effective strategy for alleviating these maladies., (© 2016 American Heart Association, Inc.)

Reactive oxygen species (ROS) play a critical role in cell signaling and disease pathogenesis. Despite their biological importance, assessment of ROS often involves measurement of indirect byproducts or measurement of ROS from excised tissue. Herein, we describe a microdialysis technique that utilizes the Amplex Ultrared assay to directly measure hydrogen peroxide (H 2 O 2 ) and superoxide in tissue of living, anesthetized rats and mice. We demonstrate the application of this methodology in the penis, adipose tissue, skeletal muscle, kidney, and liver. We provide data demonstrating the impact of important methodological considerations such as membrane length, perfusion rate, and time-dependence upon probe insertion. In this report, we provide a complete list of equipment, troubleshooting tips, and suggestions for implementing this technique in a new system. The data herein demonstrate the feasibility of measuring both in vivo H 2 O 2 and superoxide in the extracellular environment of various rodent tissues, providing a technique with potential application to a vast array of disease states which are subject to oxidative stress., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Nitric oxide (NO) signaling can be mediated not only through classic 3',5'-cyclic guanosine monophosphate but also through S-nitrosylation. However, the impact of S-nitrosylation on erectile function and in NO regulation and oxidative stress in the penis remains poorly understood., Aims: To characterize the role of S-nitrosoglutathione reductase (GSNOR), a major regulator of S-nitrosylation homeostasis, on erection physiology and on endothelial NO synthase (eNOS) function and oxidative-nitrosative stress in the penis., Methods: Adult GSNOR-deficient and wild-type (WT) mice were used. Erectile function was assessed in response to electrical stimulation of the cavernous nerve. Total NO in penile homogenates was measured by Griess reaction. Protein S-nitrosylation, eNOS phosphorylation on Ser-1177 (positive regulatory site), eNOS uncoupling, and markers of oxidative stress (4-hydroxy-2-nonenal, malondialdehyde, and nitrotyrosine) in the penis were measured by western blot., Main Outcome Measures: Erectile function, eNOS function, and oxidative stress in the penis of GSNOR-deficient mice., Results: Erectile function was intact in GSNOR-deficient mice. Total S-nitrosylated proteins were increased (P < .05) in the GSNOR(-/-) compared with WT mouse penis. Although eNOS phosphorylation on Ser-1177 did not differ between the GSNOR(-/-) and WT mouse penises at baseline, electrical stimulation of the cavernous nerve increased (P < .05) phosphorylated eNOS in the WT mouse penis but failed to increase phosphorylated eNOS in the GSNOR(-/-) mouse penis. Total NO production was decreased (P < .05), whereas eNOS uncoupling, 4-hydroxy-2-nonenal, malondialdehyde, and nitrotyrosine were increased (P < .05) in the GSNOR-deficient mouse penis compared with the WT mouse penis., Conclusion: Transnitrosylation mechanisms play an important role in regulating NO bioactivity in the penis. Deficiency of GSNOR leads to eNOS dysfunction and increased oxidative damage, suggesting that homeostatic eNOS function in the penis is governed by transnitrosylation., (Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.)

The incidence of cardiovascular disease increases progressively with age, but aging may affect men and women differently. Age-associated changes in vascular structure and function may manifest in impaired nutritive blood flow, although the regulation of nutritive blood flow in healthy aging is not well understood. The purpose of this study was to determine if nitric oxide (NO)-mediated or α-adrenergic-mediated regulation of nutritive skeletal muscle blood flow is impaired with advanced age, and if exercise training improves age-related deficiencies. Nutritive blood flow was monitored in the vastus lateralis of healthy young and aged men and women via the microdialysis-ethanol technique prior to and following seven consecutive days of exercise training. NO-mediated and α-adrenergic-mediated regulation of nutritive blood flow was assessed by microdialysis perfusion of acetylcholine, sodium nitroprusside, N(G)-monomethyl-L-arginine, norepinephrine, or phentolamine. Pretraining nutritive blood flow was attenuated in aged compared with young women (7.39 ± 1.5 vs. 15.5 ± 1.9 ml·100 g(−1)·min(−1), P = 0.018), but not aged men (aged 13.5 ± 3.7 vs. young 9.4 ± 1.3 ml·100 g(−1)·min(−1), P = 0.747). There were no age-associated differences in NO-mediated or α-adrenergic-mediated nutritive blood flow. Exercise training increased resting nutritive blood flow only in young men (9.4 ± 1.3 vs. 19.7 ml·100 g(−1)·min(−1), P = 0.005). The vasodilatory effect of phentolamine was significantly reduced following exercise training only in young men (12.3 ± 6.14 vs. −3.68 ± 3.26 ml·100 g(−1)·min(−1), P = 0.048). In conclusion, the age-associated attenuation of resting nutritive skeletal muscle blood flow was specific to women, while the exercise-induced alleviation of α-adrenergic mediated vasoconstriction that was specific to young men suggests an age-associated modulation of the sympathetic response to exercise training.

Excessive production of reactive oxygen species (ROS) are implicated in the pathogenesis of numerous disease states. However, direct measurement of in vivo ROS in humans has remained elusive due to limited access to appropriate tissue beds and the inherently short half-lives and high reactivity of ROS. Herein, we describe a novel technique by which to measure in vivo ROS in human skeletal muscle. Microdialysis probes were inserted into the vastus lateralis of eight healthy volunteers. Amplex Ultrared, a highly specific fluorogenic substrate for hydrogen peroxide (H(2)O(2)), and horseradish peroxidase (HRP), were perfused through microdialysis probes, and outflowing dialysate was collected and fluorescence was measured. Extracellular H(2)O(2) that crossed the microdialysis membrane was measured via fluorescence of the dialysate. Superoxide dismutase (SOD) was then added to the inflowing perfusion media to convert any superoxide crossing the microdialysis membrane to H(2)O(2) within the microdialysis probe. Fluorescence significantly increased (P=0.005) upon SOD addition. These data demonstrate the feasibility of measuring both in vivo H(2)O(2) and superoxide in the extracellular environment of human skeletal muscle, providing a technique with a potential application to a wide range of circulatory and metabolic studies of oxidative stress.

The aim of this study was to investigate aerobic exercise training as a means to prevent erectile dysfunction (ED) and coronary artery disease (CAD) development associated with inactivity and diet-induced obesity. Male Sprague-Dawley rats were fed a Western diet (WD) or a control diet (CD) for 12 wk. Subgroups within each diet remained sedentary (Sed) or participated in aerobic interval treadmill running throughout the dietary intervention. Erectile function was evaluated under anesthesia by measuring the mean arterial pressure and intracavernosal pressure in response to electrical field stimulation of the cavernosal nerve, in the absence or presence of either apocynin, an NADPH oxidase inhibitor, or sepiapterin, a tetrahydrobiopterin precursor. Coronary artery endothelial function (CAEF) was evaluated ex vivo with cumulative doses of ACh applied to preconstricted segments of the left anterior descending coronary artery. CAEF was assessed in the absence or presence of apocynin or sepiapterin. Erectile function (P < 0.0001) and CAEF (P < 0.001) were attenuated in WD-Sed. Exercise preserved erectile function (P < 0.0001) and CAEF (P < 0.05) within the WD. Erectile function (P < 0.01) and CAEF (P < 0.05) were augmented by apocynin only in WD-Sed, while sepiapterin (P < 0.05) only augmented erectile function in WD-Sed. These data demonstrate that a chronic WD induces impairment in erectile function and CAEF that are commonly partially reversible by apocynin, whereas sepiapterin treatment exerted differential functional effects between the two vascular beds. Furthermore, exercise training may be a practical means of preventing diet-induced ED and CAD development.

Increased fatty acid availability and oxidative stress are physiological consequences of exercise (Ex) and a high-fat, high-sugar (HFHS) diet. Despite these similarities, the global effects of Ex are beneficial, whereas HFHS diets are largely deleterious to the cardiovascular system. The reasons for this disparity are multifactorial and incompletely understood. We hypothesized that differences in redox adaptations following HFHS diet in comparison to exercise may underlie this disparity, particularly in mitochondria. Our objective in this study was to determine mechanisms by which heart and skeletal muscle (red gastrocnemius, RG) mitochondria experience differential redox adaptations to 12 weeks of HFHS diet and/or exercise training (Ex) in rats. Surprisingly, both HFHS feeding and Ex led to contrasting effects in heart and RG, in that mitochondrial H2O2 decreased in heart but increased in RG following both HFHS diet and Ex, in comparison to sedentary animals fed a control diet. These differences were determined to be due largely to increased antioxidant/anti-inflammatory enzymes in the heart following the HFHS diet, which did not occur in RG. Specifically, upregulation of mitochondrial thioredoxin reductase-2 occurred with both HFHS and Ex in the heart, but only with Ex in RG, and systematic evaluation of this enzyme revealed that it is critical for suppressing mitochondrial H2O2 during fatty acid oxidation. These findings are novel and important in that they illustrate the unique ability of the heart to adapt to oxidative stress imposed by HFHS diet, in part through upregulation of thioredoxin reductase-2. Furthermore, upregulation of thioredoxin reductase-2 plays a critical role in preserving the mitochondrial redox status in the heart and skeletal muscle with exercise.

Aims: We have previously shown that exercise leads to sustainable cardioprotection through a mechanism involving improved glutathione replenishment. This study was conducted to determine if redox-dependent modifications in glutathione reductase (GR) were involved in exercise cardioprotection. Furthermore, we sought to determine if reactive oxygen species generated by NADPH oxidase and/or mitochondria during exercise were triggering events for GR modulations., Methods and Results: Rats were exercised for 10 consecutive days, after which isolated hearts were exposed to ischaemia/reperfusion (25 min/120 min). Exercise protected against infarction and arrhythmia, and preserved coronary flow. The GR inhibitor BCNU abolished the beneficial effects. GR activity was increased following exercise in a redox-dependent manner, with no change in GR protein levels. Because fluorescent labelling of GR protein thiols showed lower amounts of reduced thiols after exercise, we sought to determine the source of intracellular reactive oxygen species that may be activating GR. Subsets of animals were exercised immediately after treatment with either NADPH-oxidase inhibitors apocynin or Vas2870, or with mitoTEMPO or Bendavia, which reduce mitochondrial reactive oxygen species levels. The cardioprotective effects of exercise were abolished if animals exercised in the presence of NADPH oxidase inhibitors, in clear contrast to the mitochondrial reagents. These changes correlated with thiol-dependent modifications of GR., Conclusion: Adaptive cardioprotective signalling is triggered by reactive oxygen species from NADPH oxidase, and leads to improved glutathione replenishment through redox-dependent modifications in GR.

Introduction.  It is suggested that erectile dysfunction (ED) may be an early risk factor for cardiovascular disease. Aim.  The goal of this study was to determine whether development of ED precedes the onset of coronary artery endothelial dysfunction in response to a Western diet (WD), thereby establishing whether the WD differentially impacts the endothelium in a time-dependent manner. Additionally, a goal was to determine if diet-induced ED is reversible with intracavernosal sepiapterin treatment. Methods.  Male Sprague-Dawley rats were fed a WD for 4, 8, or 12 weeks, or a control diet for 8 weeks. Erectile function was evaluated by measuring the mean arterial pressure (MAP) and intracavernosal pressure (ICP) in response to electrical field stimulation of the cavernosal nerve near the major pelvic ganglion, in the absence and presence of sepiapterin. Coronary artery endothelial function was evaluated ex vivo with cumulative doses of acetylcholine (ACh) applied to segments of the left anterior descending coronary artery preconstricted with serotonin. Main Outcome Measures.  Erectile function was assessed as the ICP response to electrical field stimulation (EFS), normalized to MAP. Coronary artery endothelial function was assessed as the effective concentration producing 50% of a maximal response (EC50 ) of the ACh response. Results.  The ICP/MAP response to EFS was significantly attenuated following both 8 and 12 weeks of the WD compared with the control diet (P < 0.05). Sepiapterin treatment augmented the ICP/MAP response in all WD groups (P < 0.05). The coronary artery EC50 of the ACh response was not different from control following 4 or 8 weeks but was significantly elevated following 12 weeks of the WD (P < 0.01). Conclusions.  These data suggest that erectile function is reduced prior to coronary artery endothelial function in response to the WD. Improvement of erectile function with sepiapterin in WD rats indicates that nitric oxide synthase uncoupling is a key mechanism in diet-induced ED. La Favor JD, Anderson EJ, Hickner RC, and Wingard CJ. Erectile dysfunction precedes coronary artery endothelial dysfunction in rats fed a high-fat, high-sucrose, Western pattern diet. J Sex Med 2013;10:694-703., (© 2012 International Society for Sexual Medicine.)

Study Design: Cross-sectional comparison, control group., Objectives: To investigate the relationship between carotid arterial stiffness and circulating markers for cardiovascular disease (CVD) in spinal cord-injured (SCI) subjects compared with able-bodied (AB) individuals., Setting: University Research Laboratory, University of Louisville., Methods: SCI (n=14) and AB (n=13) subjects between 20-52 years of age were recruited to participate in the study. B-mode Doppler ultrasound was used to obtain carotid artery diameter measurements. Arterial stiffness was assessed via the stiffness index and distensibility coefficient. Markers of CVD risk were obtained by fasting blood draw., Results: Carotid arterial stiffness index (P=0.061) and distensibility coefficient (P=0.370) were not different between the SCI and AB groups. The SCI group had higher high-sensitivity C-reactive protein (hsCRP) (P=0.046), triglycerides (P=0.017), leptin (P=0.040) and visfatin (P<0.001) compared with the control group. Visfatin (r=0.559, P=0.047), hsCRP (r=0.633, P=0.037), insulin (r=0.637, P=0.019) and HOMA (r=0.614, P=0.026) significantly correlated with carotid arterial stiffness index in the SCI group., Conclusion: This study demonstrated that SCI subjects are at a high cardiovascular risk as indicated by elevated hsCRP levels. Elevations in hsCRP and visfatin may contribute to accelerated atherogenic processes in the SCI population.