Small-vessel lower extremity arterial disease and erectile dysfunction: The Rancho Bernardo study

Proteomic analysis of oxidative stress response in human umbilical vein endothelial cells (HUVECs): role of heme oxygenase 1 (HMOX1) in hypoxanthine-induced oxidative stress in HUVECs

Background

Erectile dysfunction (ED) is a well-known complication of diabetes, affecting up to 75% of diabetic men. Although the etiology of diabetic ED is multifactorial, endothelial dysfunction is considered to be a pillar of its pathophysiology. Endothelial dysfunction is caused by the harmful effects of high glucose levels and increased oxidative stress on the endothelial cells that comprise the vascular endothelium. The aim of this study was to identify the proteomic changes caused by high glucose-induced oxidative stress and explore the role of heme oxygenase 1 (HMOX1) in it.

Methods

The cellular proteomic response to hypoxanthine-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) was analyzed by isobaric tags for relative and absolute quantitation (iTRAQ) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Differentially expressed proteins (DEPs) were analyzed through Network and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Further validation assays was performed to validate the role of HMOX1.

Results

The results showed that 66 and 76 DEPs were markedly upregulated and downregulated, respectively, for HUVECs oxidative stress. Among these proteins, we verified eight dysregulated genes by quantitative reverse transcription PCR, including nucleolin (NCL), X-ray repair cross-complementing protein 6 (XRCC6), ubiquinol-cytochrome C reductase binding protein (UQCRB), non-POU domain containing octamer binding (NONO), heme oxygenase 1 (HMOX1), nucleobindin 1 (NUCB1), DEK, and chromatin target of prmt1 (CHTOP). Further, using overexpression and genetic knockdown approaches, we found that HMOX1 was critical for the oxidative stress response in HUVECs.

Conclusions

We found that HMOX1 was closely related to the oxidative stress response induced by hypoxanthine. To the best of our knowledge, this study is the first overview of the responses of HUVECs to oxidative stress. The findings will contribute to analyses of the detailed molecular mechanisms involved in the pathogenesis of endothelial dysfunction and related molecular mechanisms in ED patients.

Carotid artery intima-media thickness can predict the response of patients with erectile dysfunction to phosphodiesterase 5 inhibitors

This study investigated the role of carotid artery intima-media thickness (IMT) as a morphological marker of the response of vasculogenic erectile dysfunction (ED) patients to tadalafil, one of the phosphodiesterase 5 inhibitor (PDE5-I). Through March-December 2016, 51 men with vasculogenic ED aged over 30 years were enrolled in this prospective study. Vasculogenic ED was accepted as a normal testosterone level, with penile colour Doppler ultrasonography showing arteriogenic ED, venogenic ED or mixed arteriogenic and venogenic ED. All patients underwent biochemical and hormonal blood tests, ultrasonographic evaluation of the common carotid artery (CCA) IMT and penile colour Doppler ultrasonography. On-demand tadalafil (10 mg or 20 mg in cases of a non-response to 10 mg) was administered to each patient for 2 months. ED was assessed using the short form of International Index of Erectile Function (IIEF-5) before and after the drug therapy. According to the patients' responses to the medication, they were grouped as non-responders or responders. Thirty-one of the 51 patients responded to tadalafil. The mean CCA IMT of the non-responders and responders was 0.9 ± 0.2 mm and 0.6 ± 0.2 mm, respectively (P = 0.000). The IMT of 90% of the non-responders was >0.67 mm, whereas it was >0.67 mm in 40% of the responders. The data were analysed using the Kolmogorov-Smirnov test, Chi-square test, t-test, Mann-Whitney U test and receiver operator characteristic (ROC) curves. Measurement of CCA IMT may offer an alternative and simple method to predict the response of vasculogenic ED patients to PDE5-Is.

The relationship of erectile dysfunction and subclinical cardiovascular disease: A systematic review and meta-analysis

Erectile dysfunction (ED) is associated with cardiovascular disease (CVD) and CVD mortality. However, the relationship between ED and subclinical CVD is less clear. We synthesized the available data on the association of ED and measures of subclinical CVD. We searched multiple databases for published literature on studies examining the association of ED and measures of subclinical CVD across four domains: endothelial dysfunction measured by flow-mediated dilation (FMD), carotid intima–media thickness (cIMT), coronary artery calcification (CAC), and other measures of vascular function such as the ankle–brachial index, toe–brachial index, and pulse wave velocity. We conducted random effects meta-analysis and meta-regression on studies that examined an ED relationship with FMD (15 studies; 2025 participants) and cIMT (12 studies; 1264 participants). ED was associated with a 2.64 percentage-point reduction in FMD compared to those without ED (95% CI: –3.12, −2.15). Persons with ED also had a 0.09-mm (95% CI: 0.06, 0.12) higher cIMT than those without ED. In subgroup meta-analyses, the mean age of the study population, study quality, ED assessment questionnaire (IIEF-5 or IIEF-15), or the publication date did not significantly affect the relationship between ED and cIMT or between ED and FMD. The results for the association of ED and CAC were inconclusive. In conclusion, this study confirms an association between ED and subclinical CVD and may shed additional light on the shared mechanisms between ED and CVD, underscoring the importance of aggressive CVD risk assessment and management in persons with ED.

Uric acid level and erectile dysfunction in patients with coronary artery disease

INTRODUCTION

Erectile dysfunction (ED) is a frequent complaint of elderly subjects and is closely associated with endothelial dysfunction and cardiovascular disease (CVD). Uric acid is also associated with endothelial dysfunction, oxidative stress, and CVD, raising the hypothesis that an increased serum uric acid might predict ED in patients who are at risk for coronary artery disease (CAD).

AIM

This study aims to evaluate the association of serum uric acid levels with presence and severity of ED in patients presenting with chest pain of presumed cardiac origin.

METHODS

This is a cross-sectional study of 312 adult male patients with suspected CAD who underwent exercise stress test (EST) for workup of chest pain and completed a sexual health inventory for men survey form to determine the presence and severity of ED. Routine serum biochemistry (and uric acid levels) were measured. Logistic regression analysis was used to assess risk factors for ED.

MAIN OUTCOME MEASURES

The short version of the International Index of Erectile Function questionnaire diagnosed ED (cutoff score ≤ 21). Serum uric acid levels were determined. Patients with chest pain of suspected cardiac origin underwent an EST.

RESULTS

One hundred forty-nine of 312 (47.7%) male subjects had ED by survey criteria. Patients with ED were older and had more frequent CAD, hypertension, diabetes and impaired renal function, and also had significantly higher levels of uric acid, fibrinogen, glucose, C-reactive protein, triglycerides compared with patients without ED. Uric acid levels were associated with ED by univariate analysis (odds ratio = 1.36, P = 0.002); however, this association was not observed in multivariate analysis adjusted for estimated glomerular filtration rate.

CONCLUSION

Subjects presenting with chest pain of presumed cardiac origin are more likely to have ED if they have elevated uric acid levels.

Anatomy, physiology, and pathophysiology of erectile dysfunction

INTRODUCTION

Significant scientific advances during the past 3 decades have deepened our understanding of the physiology and pathophysiology of penile erection. A critical evaluation of the current state of knowledge is essential to provide perspective for future research and development of new therapies.

AIM

To develop an evidence-based, state-of-the-art consensus report on the anatomy, physiology, and pathophysiology of erectile dysfunction (ED).

METHODS

Consensus process over a period of 16 months, representing the opinions of 12 experts from seven countries.

MAIN OUTCOME MEASURE

Expert opinion was based on the grading of scientific and evidence-based medical literature, internal committee discussion, public presentation, and debate.

RESULTS

ED occurs from multifaceted, complex mechanisms that can involve disruptions in neural, vascular, and hormonal signaling. Research on central neural regulation of penile erection is progressing rapidly with the identification of key neurotransmitters and the association of neural structures with both spinal and supraspinal pathways that regulate sexual function. In parallel to advances in cardiovascular physiology, the most extensive efforts in the physiology of penile erection have focused on elucidating mechanisms that regulate the functions of the endothelium and vascular smooth muscle of the corpus cavernosum. Major health concerns such as atherosclerosis, hyperlipidemia, hypertension, diabetes, and metabolic syndrome (MetS) have become well integrated into the investigation of ED.

CONCLUSIONS

Despite the efficacy of current therapies, they remain insufficient to address growing patient populations, such as those with diabetes and MetS. In addition, increasing awareness of the adverse side effects of commonly prescribed medications on sexual function provides a rationale for developing new treatment strategies that minimize the likelihood of causing sexual dysfunction. Many basic questions with regard to erectile function remain unanswered and further laboratory and clinical studies are necessary.

Circulating endothelial progenitor cells: a new approach to anti-aging medicine?

Endothelial dysfunction is associated with major causes of morbidity and mortality, as well as numerous age-related conditions. The possibility of preserving or even rejuvenating endothelial function offers a potent means of preventing/treating some of the most fearful aspects of aging such as loss of mental, cardiovascular, and sexual function.

Endothelial precursor cells (EPC) provide a continual source of replenishment for damaged or senescent blood vessels. In this review we discuss the biological relevance of circulating EPC in a variety of pathologies in order to build the case that these cells act as an endogenous mechanism of regeneration. Factors controlling EPC mobilization, migration, and function, as well as therapeutic interventions based on mobilization of EPC will be reviewed. We conclude by discussing several clinically-relevant approaches to EPC mobilization and provide preliminary data on a food supplement, Stem-Kine, which enhanced EPC mobilization in human subjects.