Evaluation of serum oxidative and antioxidative status in patients with erectile dysfunction

Antioxidant Supplementation for Erectile Dysfunction: Systematic Review and Meta-Analysis of Double-Blind, Randomized, Placebo-Controlled Trials

PURPOSE

This meta-analysis aimed to determine the efficacy and safety of antioxidant supplementation for treating erectile dysfunction (ED).

MATERIALS AND METHODS

We systematically searched MEDLINE, Embase, and the Cochrane Library for double-blind, randomized, placebo-controlled trials of oral antioxidant supplementation in men with ED. Erectile function was assessed by the International Index of Erectile Function-Erectile Function domain (IIEF-EF) score. Using random-effects meta-analysis models, antioxidant and placebo groups were compared for erectile function using the mean difference in IIEF-EF score adjusted to a 6-30 scale and for side effects using the log risk ratio.

RESULTS

The review included 23 trials of 1,583 men (median age 51 years) treated with antioxidant supplementation or placebo for a median of 12 weeks (range, 4 weeks to 6 months). Antioxidant supplementation significantly improved erectile function compared to placebo, with a mean difference of 5.5 points (95% confidence interval [CI]: 3.7 to 7.3; p<0.001) on the IIEF-EF. In meta-regression, the treatment benefit was greater in men with more severe ED (p<0.001). Side effects were uncommon, none were serious, and the frequency was comparable between antioxidant (3.8%) and placebo (2.1%) groups (log risk ratio=0.36; 95% CI: -0.24 to 0.97; p=0.24).

CONCLUSIONS

Antioxidant supplementation appears safe and significantly improves erectile function in men with ED, particularly those with more severe symptoms. Limitations of this review included unknown long-term efficacy and safety and the inability to make specific product and dosing recommendations due to the variety of antioxidants and regimens studied.

Association of oxidative stress with erectile dysfunction in community-dwelling men and men on dialysis

OBJECTIVES

To investigate the association between oxidative stress and erectile dysfunction (ED) in community-dwelling men and men on dialysis.

METHODS

This cross-sectional study included 398 community-dwelling men and 42 men on dialysis. Oxidative stress was assessed using 8-hydroxy-2'-deoxyguanosine (8-OHdG). Univariable and multivariable logistic regression analyses were performed to evaluate the association between oxidative stress and ED.

RESULTS

Spearman's rank correlation test showed no significant correlation between urine 8-OHdG levels and the 5-Item International Index of Erectile Function scores in community-dwelling men (ρ = -0.005, p = 0.917) and between plasma 8-OHdG levels and the Sexual Health Inventory for Men scores in men on dialysis (ρ = 0.166, p = 0.295). In community-dwelling men, univariable and multivariable analyses revealed that urine 8-OHdG level was not significantly associated with ED (odds ratio [OR]: 1.005, 95% confidence interval [CI]: 0.884-1.144, p = 0.934; OR: 0.930, 95% CI: 0.798-1.084, p = 0.353; respectively). In men on dialysis, univariable analyses revealed that plasma 8-OHdG level was not significantly associated with severe ED (OR: 0.967, 95% CI: 0.876-1.066, p = 0.498).

CONCLUSIONS

Oxidative stress was not significantly associated with ED prevalence and severity in community-dwelling men and men on dialysis.

Utilization of fruit and vegetable waste as an alternative feed resource for sustainable and eco-friendly sheep farming

Globally, 10-20% of horticultural wastes are disposed in landfills leading to environmental pollution. Recycling these wastes as animal feedstuff will lessen food-feed competition and minimize environmental hazards. The present study was undertaken to determine the nutritional quality of fresh fruit and vegetable waste (F&VW) and their dietary inclusion on nutrient utilization, antioxidant status, greenhouse gases (GHG) emissions and potable water sparing efficacy in sheep. Three dietary combinations were formulated i.e. control (C):70% Cenchrus ciliaris hay +30% concentrate mixture (CM), diet with fruit waste (FWD):70% Cenchrus ciliaris hay +20% CM +10% FW and diet with vegetable waste (VWD):70% Cenchrus ciliaris hay +20% CM +10% VW for in vitro and in vivo evaluation of these wastes as potential livestock feed. Twenty-one adult ewes were allocated into 3 groups C, FWD and VWD and fed on the above three diets. Dry matter and crude protein digestibility were significantly enhanced by 5.5 and 7.2%; 7.3 and 7.6% in F&VW supplemented groups, respectively, without affecting feed intake. Plasma total antioxidant capacity (TAC) was improved by 32.2 and 26.3% in F&VW supplemented groups. Inclusion of F&VW biomass reduced annual methane (CH₄) and nitrous oxide (N₂O) emissions (kg CO₂eq/sheep) by 3.12 and 4.55%; 15.18 and 14.92% and thus contributed to lowering of global warming potential by 4.00 and 5.27%, respectively. Furthermore, there was a net reduction of potable water consumption by 21.78 and 13.92% in F&VW supplemented groups, respectively. Therefore, it can be concluded that F&VW can be a potential feedstuff for ruminants and its efficient reuse would minimize environmental impacts associated with disposal of such waste in the landfills.

The relationship of thiol/disulfide homeostasis in the etiology of patients with obstructive sleep apnea: a case-control study

AIM

Obstructive sleep apnea syndrome (OSAS) is a chronic and incapacitating disease that often requires lifelong care. This study aimed to evaluate the thiol/disulfide homeostasis in patients with OSAS, to compare the thiol/disulfide levels with the control group and to investigate their relationship with the severity of the disease.

MATERIAL AND METHODS

Patients who were admitted to the department of chest diseases, and diagnosed with OSAS using polysomnographic analysis (n = 186) and 144 patients who underwent polysomnography due to some reasons but ruled out of having OSAS were included in the study. Serum total thiol (TT), native thiol (SH), and disulfide thiol (SS) levels were measured from the participants; SS/SH, SS/TT, and SH/TT percent ratios were calculated and compared between the patient and control groups.

RESULTS

The mean (±SD) age of the patients and control participants was 52.0 ± 11.5 years and 44.9 ± 13.2 years, respectively. Compared to the control group, patients with OSAS had significantly lower SH (239.3 ± 56.3 μmol/L vs. 258.6 ± 65.3μmol/L, t = 2.70, p =.007) and TT levels (273.2 ± 60.1 μmol/L vs. 292.9 ± 67.5μmol/L, t = 2.64, p=.010). Age (OR = 1.04), serum albumin (OR = 12.67), ischemia-modified albumin (IMA) (OR = 0.12), SH (OR = 0.81), and TT (OR = 1.17) were independent predictors of OSAS.

CONCLUSIONS

These results support the idea that decreased ST and TT levels are related to increased oxidative stress. On the other hand, impaired thiol balance may play a significant role in the pathogenesis of OSAS.

The correlation between atherogenic indexes and erectile dysfunction

Aside from the ordinary plasma lipid level measurements, the ratios based on individual plasma lipid levels such as atherogenic index of plasma (AIP), Castelli's risk index 1/2 (CRI-1/2), and atherogenic coefficient (AC) are the novel parameters to evaluate the patients with a high risk of CVD. In this study, we aim to evaluate the relationship between AIP, AC, and CRI-1/2 with increased risk of ED. Between April 2018 and February 2019, 253 patients, who were diagnosed as a vasculogenic ED in our clinic, were enrolled in the study. While the first group (n = 134) consisted of patients with moderate and mild ED (IIEF-EF: 17-30), the second group (n = 119) consisted of patients with severe ED. In addition to the mean values of lipid parameters; CRI-1 (total cholesterol/HDL), CRI-2 (LDL/HDL) AIP (log10(triglycerides/HDL), and AC (non-HDL/HDL) were calculated. The mean age was 44.02 ± 10.41 (24-70), and the mean BMI was 27.80 ± 4.12 (18.52 ± 41.97). However, CRI-1 and AIP values were found to be higher in the severe ED group compared to the mild ED group (CRI-1: 4.50 ± 1.47, 4.88 ± 1.30; p = .039; AIP: 0.489 ± 0.315, 0.617 ± 0.283; p = .007). Our results demonstrated that CR-1 and AIP have a positive correlation with the severity of ED. Moreover, we can suggest that patients with higher CR-1 and AIP values are likely to have more severe ED in the future.

Thiol/Disulfide Homeostasis in Patients With Erectile Dysfunction

BACKGROUND

Although there are no sufficient data on association between oxidative stress and erectile dysfunction (ED), numerous studies have reported that imbalance between the formation of reactive oxygen species and body's antioxidant defenses may play a role in the pathogenesis of ED.

AIM

The aim of this study was to determine and compare the oxidant and antioxidant status in patients with ED and healthy controls with a novel automated assay for thiol/disulphide homeostasis test.

METHODS

Our study included 123 patients with ED and 90 healthy individuals. ED was evaluated by asking questions 1-5 and 15 of the International Index of Erectile Function form. In this study, we used Erel and Neselioglu's thiol/disulfide homeostasis test, which is one of the novel methods that can measure both variables of the oxidative/antioxidative balance individually and collectively.

OUTCOMES

This method measured serum antioxidant (total thiol [toSH], native thiol [SH]) and oxidant (disulfide [SS]) levels. The statistical comparisons were performed between patients with ED (ED+ group) and without ED (ED- group) first and then within the ED+ group. After toSH, SH, and SS levels were determined; SS/toSH%, SS/SH%, and SH/toSH% levels were analyzed separately and compared statistically.

RESULTS

We found a significant difference between ED- and ED+ groups in terms of toSH, SH, SS/toSH%, and SS/SH% ratios. SS parameters were increased in patients with ED, but there was no significant difference in terms of SS and SH/toSH% values.

CLINICAL IMPLICATIONS

Clarification of the factors involved in the etiology of ED such as oxidative/antioxidative balance may open new grounds in the early diagnosis and treatment of the disease.

STRENGTHS & LIMITATIONS

It is a prospective, randomized clinical study with the use of a novel, reliable, and fully automated technique. The limitations of the study are use of a subjective tool such as the International Index of Erectile Function, obtaining blood samples from the peripheral vein instead of penile cavernosal tissue, and relatively small sample size.

CONCLUSION

The results of this study showed that thiol/disulfide homeostasis is altered in ED, and this imbalance may be a factor in its pathophysiology. We determined that as ED gets more severe, toSH and SH parameters decrease, whereas SS parameter increases. Micoogullari U, Karatas OF, Kisa E, et al. Thiol/Disulfide Homeostasis in Patients With Erectile Dysfunction. J Sex Med 2020;17:1934-1941.

Evaluation of factors affecting sexual dysfunction in female patients with diabetes mellitus

OBJECTIVE

Our objective in this study was to evaluate the factors predicting female sexual dysfunction (FSD) in patients with diabetes mellitus (DM).

SUBJECTS AND METHODS

The study included 149 women with DM. Sexual function was evaluated with the Female Sexual Function Index (FSFI) questionnaire, in which total scores under 26.55 characterized the occurrence of FSD (Group 1 > 26.55, Group 2 < 26.55). We recorded the patients' demographic, metabolic, and hormonal data. Ophthalmologic, neurologic, and renal complications were also evaluated. The antioxidant status of the patients in both groups was determined by measuring the activity of the enzymes paraoxonase-1 (PON-1) and arylesterase (ARE).

RESULTS

Based on the FSFI scores, 60 patients were allocated to Group 1 (26.6 ± 12.3) and 89 to Group 2 (22.6 ± 9.5). Group 2 compared with Group 1 had significantly (p < 0.05) higher mean concentrations of glycated hemoglobin (HbA1c), glucose, triglycerides, and insulin, along with higher rates of metformin use, smoking, retinopathy, and nephropathy. The mean serum ARE concentrations were significantly lower in Group 2 compared with Group 1 (p = 0.000), but the mean serum PON-1 concentrations were similar between both groups (p = 0.218). On multivariable regression analysis, age, ARE activity, Beck Depression Inventory (BDI) score, and menopause were significant independent predictors of FSD (p < 0.05).

CONCLUSIONS

In this study, we evaluated the predictive factors determining FSD caused by DM. Despite the significant results found in our study, future randomized controlled studies with a long follow-up and a larger number of patients are required to determine how DM affects FSD.

Platelet indices and erectile dysfunction: A systematic review and meta-analysis

Elevated platelet levels have been postulated to be associated with cardiovascular diseases, conditions closely linked to erectile dysfunction (ED). The current systematic review and meta-analysis was performed to assess the platelet indices, which including platelet count (PLT), mean platelet volume (MPV) and platelet distribution width (PDW) in subjects with ED compared to controls in an attempt to clarify the possible role of platelet indices in the pathogenesis of ED. We initially screened the candidate studies observing the possible association between platelet indices and ED following literature search of database Cochrane Library, PubMed, EMBASE and MEDLINE and therefore included the studies based on the pre-defined inclusion and exclusion criteria. Two independent investigators extracted the related information on article data and outcome measures from the qualified studies, and a meta-analysis was therefore performed using Stata 12.0 software. Subgroup analyses were conducted by the different ED aetiology obtained from the eligible studies. The standard mean difference (SMD) and the corresponding 95% confidence intervals (95% CIs) were applied to estimate the outcome measures. A total of 14 articles were qualified in our meta-analysis with a total of 1595 cases and 987 controls included. Pooled estimate was in favour of increased MPV levels in subjects with ED with a SMD of 0.651 fl, 95% CI 0.567-0.735, p = 0.000. Subgroup analysis showed that vasculogenic ED had a higher MPV levels than controls as well (SMD [95% CI] = 1.026 [0.823-1.228], p = 0.000). However, pooled analysis based on PLT and PDW levels has produced inconsistent results and not strong evidence on platelet level and ED correlation. In conclusion, vasculogenic ED patients had a higher MPV level in our study. However, the results need further interpretation with caution and more high-quality studies are warranted.

Skin autofluorescence (a marker for advanced glycation end products) and erectile dysfunction in diabetes

AIM

Although diabetes-related erectile dysfunction (ED) has many etiological factors, little is known about the putative pathophysiological role of advanced glycation end products (AGEs). Skin autofluorescence is a noninvasive marker of AGEs. Recent studies have evidenced a relationship between skin autofluorescence and several complications of diabetes. We hypothesized that AGEs (assessed by skin autofluorescence) are associated with ED in diabetes patients.

METHODS

Between March 2014 and April 2015, 42 patients with type 1 diabetes (T1D) and 44 patients with type 2 diabetes (T2D) were consecutively enrolled in a descriptive, cross-sectional study and compared to 54 healthy controls. ED was evaluated via the 5-item version of the International Index of Erectile Function (IIEF-5). Skin autofluorescence was measured on the volar aspect of the arm with an AGE-Reader.

RESULTS

Patients with diabetes had a mean±standard deviation age of 50±15 and a mean duration of diabetes of 16±12years. Skin autofluorescence was strongly and significantly correlated with the IIEF-5 score in the T1D subgroup (r=-0.52; P=0.004), the T2D subgroup (r=-0.32; P<0.03) and in the whole group of diabetic patients (r=-0.49; P<0.0001). In multivariate analyses that controlled for potentially confounding clinical and biochemical factors, only skin autofluorescence was still significantly correlated with the IIEF-5 score (P<0.0001). A receiver operating characteristic analysis revealed that a skin autofluorescence value ≥3.2AU determined severe ED with a sensitivity of 60% and a specificity of 87% in diabetic patients.

CONCLUSION

Skin autofluorescence is significantly associated with ED in diabetes, independently of classical confounding factors.

Erectile dysfunction is a marker for obstructive sleep apnea

PURPOSE

To investigate the prevalence of erectile dysfunction (ED) in patients with obstructive sleep apnea (OSA) with and without any other comorbidities.

METHODS

The patient group was newly diagnosed as having OSA (apnea-hypopnea index [AHI] > 5/h) using a polysomnographic examination. A group of subjects with simple snoring were included into the control group. Clinically relevant comorbidities were systematically assessed in face-to-face interviews. All patients were asked to complete the 15-item International Index of Erectile Function (IIEF-15) questionnaire for the evaluation of ED. The patients with OSA and ED were evaluated according to these comorbidities.

RESULTS

Of the 94 patients, 39 patients were excluded because of severe diseases. OSA was observed in 38 (69.1%) of the 55 patients. ED was seen in 24 (63.2%) patients with OSA, and in 8 (47.1%) patients without OSA (p > 0.05). There were no statistical differences between the groups' ages, IIEF scores, and body mass index (BMI) scores. There were statistically significant differences between the groups' AHI scores (p < 0.05). There was a significant correlation between the groups' AHI scores, BMI, and age (p < 0.05). There was no statistically significant difference in patients with OSA, with and without comorbidity in terms of ED.

CONCLUSION

The rate of ED was higher in patients with OSA who had no other comorbidities. Therefore, ED can be a sensitive marker of OSA.

Association between plasma fluorescent oxidation products and erectile dysfunction: A prospective study

BACKGROUND

Existing epidemiological studies of the association between oxidative stress and erectile dysfunction (ED) are sparse and inconclusive, which is likely due to cross-sectional design and small sample size. Therefore, we investigated the association between biomarkers of oxidative stress and ED in prospective setting among a relatively large sample size of men.

METHODS

We conducted the prospective study among 917 men ages between 47 and 80 years at the time of blood draw, which is a part of nested prospective case-control study of prostate cancer in the Health Professionals Follow-up Study. Plasma fluorescent oxidation products (FlOPs), a global biomarker for oxidative stress, were measured at three excitation/emission wavelengths (360/420 nm named as FlOP_360; 320/420 nm named as FlOP_320 and 400/475 nm named as FlOP_400).

RESULTS

Approximately 35% of men developed ED during follow-up. We did not find an independent association between FlOP_360, FlOP_320, FlOP_400 and risk of ED in the multivariable adjusted model (Tertile 3 vs. tertile 1: odds ratio [OR] = 0.90, 95% confidence interval [CI] = 0.61-1.34, P(trend) = 0.54 for FlOP_360; OR = 0.73, 95% CI = 0.49-1.07, P(trend) = 0.27 for FlOP_320; and OR = 0.98, 95% CI = 0.66-1.45, P(trend) = 0.72 for FlOP_400). Further analysis of the association between FlOPs and ED in the fasting samples or controls only (free of prostate cancer incidence) did not change the results appreciably.

CONCLUSIONS

Plasma FlOPs were not associated with the risk of ED, suggesting oxidative stress may not be an independent risk factor for ED.