Serum Biomarkers of Erectile Dysfunction in Diabetes Mellitus: A Systematic Review of Current Literature

Mapping the mitochondrial landscape in T2DM: key findings from 2003-2023

Backgound

T2DM, a chronic metabolic disorder, poses a significant threat to global public health. Mitochondria play a crucial role in the pathogenesis of T2DM. This study intends to investigate the correlation between mitochondria and T2DM over the past two decades (2003-2023) through bibliometric analysis. Its objectives are to pinpoint trends, emphasize research priorities, and establish a foundation for future investigations.

Methods

A literature search was conducted using the SCI-E database. All recorded results were downloaded in plain text format for further analysis. The following terms were analyzed using Vosviewer 1.6.18, citespace 6.3r1, bibliometrix in RStudio (v.4.4.1), and Microsoft Excel 2021: country, institution, author, journal, references, and keywords.

Results

From January 1, 2003 to December 31, 2023, a total of 2,732 articles were retrieved. The United States, China, and Italy contributed most of the records. UNIVERSITY OF CALIFORNIA SYSTEM, INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICAL INSERM, and US DEPARTMENT OF VETERANS AFFAIRS were the top 3 most productive institutions. rocha milagros, victor victor m had the most publications, followed by roden michael, and petersen kf had the most citations together. DIABETES published the most articles on research on this topic, followed by AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM, DIABETOLOGIA. The key points of this topic are the relationship between mitochondria and T2DM, the skeletal muscle mitochondrial changes observed in T2DM, and the impact of mitochondrial dysfunction on T2DM. Over the past five years, particle dynamics, mitochondrial dysfunction, and mechanism research have emerged as significant focal points in this field.

Conclude

This paper successfully identified the key areas and emerging trends in the relationship between mitochondria and T2DM, thereby offering valuable insights for future research.

Role of circulating microparticles and cytokines in periodontitis associated with diabetes

Background

Periodontitis is a chronic inflammatory condition that affects the supporting tissues of the teeth, and can lead to serious complications such as tooth loss and systemic health problems, including diabetes, which have a bidirectional relationship with periodontitis. Circulating microparticles originate from different cell types after stimuli such as activation or apoptosis. Interleukins are related to processes in the regulation of the immune response, inflammation, and cell growth. This study aimed to evaluate circulating microparticles as well as interleukins in the plasma, at baseline and 1 month after the end of the non-surgical periodontal treatment.

Methods

Samples were collected from 45 patients, with moderate to severe periodontitis with diabetes (N = 25) and without diabetes (N = 20). Microparticles were evaluated in the platelet-poor plasma by flow cytometer. Cytokine levels were evaluated by the enzyme immunoabsorption assay (ELISA).

Results

Higher levels of the pro-inflammatory cytokines were found in the group with diabetes compared to the non-diabetic group both at baseline and 1 month after the end of the treatment. A higher IL-6/IL-10 ratio was found in patients with diabetes compared to the group without diabetes at T0 and T1, whereas an increased IFN-γ/IL-10 ratio was only found at T1 in patients with diabetes in comparison to the group without diabetes. In the group with diabetes, it was verified positive correlations between IL-10 and IL-6 or IFN-γ and a negative correlation between IL-6 and PMP, at T0; in contrast, in the T1, negative correlations were found between TNF-α and IL-10 or PMP. Besides, at T0, it was evidenced positive correlations both between circulating TNF-α and IL-6, and IL-10 and EMP, as well as a negative correlation between IL-10 and PMP in the group with diabetes. In addition, it was observed in T1 positive correlations between levels of TNF-α and IL-6, IFN-γ, or IL-10, and between PMP and IFN-γ, and between EMP and IL-6, TNF-α and IFN-γ in this group.

Conclusion

The results suggest a modulatory effect of the periodontitis associated with diabetes, as well as the periodontal treatment, in the systemic inflammatory status of the participants of the study.

Nitro-oleic acid ameliorates erectile dysfunction in a streptozotocin-induced rat model of diabetes by inhibiting oxidative stress and apoptosis and activating the NO/cGMP pathway

The major vascular complications associated with diabetes make the management of diabetic mellitus erectile dysfunction (DMED) a challenging endeavor. Notable factors contributing to DMED include oxidative stress, nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway activation, and apoptosis, while nitro-oleic acid (NO 2 -OA) has been shown to be beneficial in treating these aspects of this condition. We, herein, investigated the effects and possible mechanisms of NO 2 -OA on erectile function as assessed in a streptozotocin-induced rat model of diabetes. Our results revealed that the erectile function of DMED rats was significantly impaired compared with that of the control group. However, in response to 4 weeks of NO 2 -OA treatment, there was an improvement in erectile function. The expression of oxidative stress-related indicators was significantly increased and the NO/cGMP pathway was impaired in the DMED group. The expression of proapoptotic factors was increased, while that of antiapoptotic factors was decreased in the DMED group. Moreover, the cell morphology in the cavernous tissue of the DMED group also changed adversely. NO 2 -OA treatment significantly reversed all these changes observed in the DMED group. In conclusion, NO 2 -OA treatment partially improved erectile function in DMED rats through mechanisms that included inhibition of oxidative stress, activation of the NO/cGMP pathway, and a reduction in apoptosis.

Circulating and Urinary Concentrations of Malondialdehyde in Aging Humans in Health and Disease: Review and Discussion

(1) Background: Malondialdehyde (MDA) is a major and stable product of oxidative stress. MDA circulates in the blood and is excreted in the urine in its free and conjugated forms, notably with L-lysine and L-serine. MDA is the most frequently measured biomarker of oxidative stress, namely lipid peroxidation. Oxidative stress is generally assumed to be associated with disease and to increase with age. Here, we review and discuss the literature concerning circulating and excretory MDA as a biomarker of lipid peroxidation in aging subjects with regard to health and disease, such as kidney disease, erectile dysfunction, and COVID-19. (2) Methods: Scientific articles, notably those reporting on circulating (plasma, serum) and urinary MDA, which concern health and disease, and which appeared in PubMed were considered; they formed the basis for evaluating the potential increase in oxidative stress, particularly lipid peroxidation, as humans age. (3) Results and Conclusions: The results reported in the literature thus far are contradictory. The articles considered in the present study are not supportive of the general view that oxidative stress increases with aging. Many functions of several organs, including the filtration efficiency of the kidneys, are physiologically reduced in men and women as they age. This effect is likely to result in the apparent "accumulation" of biomarkers of oxidative stress, concomitantly with the "accumulation" of biomarkers of an organ's function, such as creatinine. How free and conjugated MDA forms are transported in various organs (including the brain) and how they are excreted in the urine via the kidney is not known, and investigating these questions should be the objective of forthcoming studies. The age- and gender-related increase in circulating creatinine might be a useful factor to be taken into consideration when investigating oxidative stress and aging.

Evaluation of serum levels of Irisin as a marker of endothelial dysfunction in patients with type 2 diabetes mellitus

INTRODUCTION

Insulin resistance and obesity have been associated with irisin, a protein in fat cells. The levels of irisin in patients with type 2 diabetes mellitus (T2DM) were significantly lower than those in non-diabetics. This study aimed to examine the relationship between serum irisin levels and endothelial dysfunction in patients with T2DM.

METHODS

There were 90 participants in this study. We matched 65 patients with T2DM with 25 healthy control participants. A series of tests were performed on the participants, including fasting blood glucose, 2 hours postprandial blood glucose, glycated haemoglobin, triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), TG/HDL-C ratio and albumin/creatinine ratio. In addition to measuring high-sensitivity C-reactive protein (hs-CRP). Enzyme-linked immunosorbent assay (ELISA) technique was used for estimating irisin concentrations.

RESULTS

Flow-mediated dilation (FMD) was significantly lower in patients with T2DM; however, there was a non-statistically significant difference between healthy controls and patients with T2DM regarding serum Irisin level. CRP and LDL levels were inversely correlated with circulating irisin levels. In a stepwise regression analysis, only the hs-CRP and LDL were statistically significant in predicting irisin level.

CONCLUSIONS

In patients with T2DM, serum levels of irisin were inversely correlated with hyperglycaemia, body mass index and per cent body fat; this suggests that detecting irisin levels early can prevent cardiovascular diseases from progressing. According to the study results, serum irisin serves as a predictive marker for early cardiovascular disease, thus preventing the disease from progressing. There is a need for further research in order to understand how irisin contributes to the development of atherosclerosis and the development of diabetic complications.

N-acetylcysteine improves diabetic associated erectile dysfunction in streptozotocin-induced diabetic mice by inhibiting oxidative stress

Oxidative stress appears to play a role in the pathogenesis of diabetes mellitus erectile dysfunction (DMED). This study aimed to investigate the effect of N‐acetylcysteine (NAC) on DMED in streptozotocin‐induced diabetic mice and to explore potential mechanisms. In the present study, we show that an erectile dysfunction is present in the streptozotocin‐induced mouse model of diabetes as indicated by decreases in intracavernous pressure responses to electro‐stimulation as well as from results of the apomorphine test of erectile function. After treatment of NAC, the intracavernous pressure was increased. In these DMED mice, oxidative stress and inflammatory responses were significantly reduced within the cavernous microenvironment, while activity of antioxidant enzymes in this cavernous tissue was enhanced after NAC treatment. These changes protected mitochondrial stress damage and a significant decreased in apoptosis within the cavernous tissue of DMED mice. This appears to involve activation of the nuclear factor erythroid 2‐like‐2 (Nrf2) signalling pathway, as well as suppression of the mitogen‐activated protein kinase (MAPK) p38/ NF‐κB pathway within cavernous tissue. In conclusion, NAC can improve erectile function through inhibiting oxidative stress via activating Nrf2 pathways and reducing apoptosis in streptozotocin‐induced diabetic mice. NAC might provide a promising therapeutic strategy for individuals with DMED.

Prevalence and associated factors of erectile dysfunction in men with type 2 diabetes mellitus in eastern Sudan

BACKGROUND

Diabetes mellitus (DM) is a global health threat and burden that is associated with many chronic complications. Erectile dysfunction (ED) among patients with DM is one of these complications. There is no published data on ED in Sudan; hence, we conducted this study to evaluate the prevalence of ED and the associated factors in patients with type 2 diabetes mellitus (T2DM) in eastern Sudan.

METHODS

We performed a cross-sectional study. Data on blood glucose level, cholesterol level, anthropometric and demographic characteristics, results of the International Index of Erectile Function (IIEF-5) questionnaire, and clinical history were obtained.

RESULTS

A total of 334 men with T2DM with a median (interquartile range [IQR]) age of 55.0 (±10.0) years were enrolled in the study. The median (IQR) of the duration of DM was 7.0 (±8) years, and 260 (77.8%) had uncontrolled T2DM. The median (IQR) body mass index was 24.5 (±4.9) kg/m2. Of the participants, 81 (24.3%) had severe ED, 52 (15.6%) had moderate ED, 75 (22.5%) had mild to moderate ED, and 63 (13.9%) had mild ED. Of the 334 men, 271 (81.1%) had ED. Logistic regression analysis showed that age (adjusted Odds Ratio [AOR] = 1.07, 95% confidence interval [CI] = 1.01-1.14), duration of DM (AOR = 1.26, 95% CI = 1.06-1.51), and cholesterol levels (AOR = 3.53, 95% CI = 1.75-7.11) were positively associated with ED. Moreover, poor glycaemic control (AOR = 3.38, 95% CI = 1.70-6.71, P < 0.001) was significantly associated with ED.

CONCLUSION

There is a high prevalence of ED among patients with T2DM in eastern Sudan. Age, duration of DM, and cholesterol were positively associated with ED.

Diagnostic work up: Laboratory and biomarkers

This chapter will focus on the diagnostic work around sexual dysfunction in Parkinson's disease, especially laboratory tests and biomarkers. A number of methods to analyze if sexual dysfunction is caused by neural pathology, vascular dysfunction or other mechanisms are now available. Other methods can be used to differentiate between psychogenic/functional reasons behind sexual dysfunction and organic ones. The role of biomarkers for diagnosis, but also for understanding the reason behind and for counteracting sexual dysfunction is becoming more evident. There is also a rich and increasing number of scales and other instruments available for detecting and quantifying sexual hypo- and hyperactivity. When investigating the reason behind sexual dysfunction in patients with Parkinson's disease comorbidities should also be considered. Finally, early and pronounced sexual dysfunction might in some cases be an indication that differential diagnosis, like Multisystem Atrophy, should be thought about. All these aspects of the diagnostic procedures around sexual dysfunction in Parkinson's disease will be covered in this chapter.

Erectile dysfunction iceberg in an urology outpatient clinic: How can we encourage our patients to be more forthcoming?

The study's aim was to document the rates of declared and hidden erectile dysfunction (ED) at urology outpatient clinic while attempting to develop a method to encourage patients to talk about ED. A total of 506 patients, all of whom underwent the same procedure by the same clinician with a standard algorithm, were prospectively evaluated. The patients who declared ED as their primary or secondary symptom were grouped as 'very early treatment seekers' (VETS) and 'early treatment seekers' (ETS) respectively. The patients who hid their ED until directly questioned and the patients whose ED was diagnosed with an IIEF-5 questionnaire were grouped as 'late treatment seekers' (LTS) and 'very late treatment seekers' (VLTS) respectively. The total number of ED was 291 (57.5%), comprised of 54 (18.6%) patients in the VETS, 48 (16.5%) in the ETS, 143 (49.1%) in the LTS and 46 (15.8%) in the VLTS groups. The rate of severe ED was significantly higher in the VETS group, whereas the rate of mild ED was significantly higher in the VLTS group (p < .001). Most of the patients would not seek help for their ED until the clinician directly or indirectly questioned them. Simple manipulations uncovered the hidden ED patients.

The relationship between serum irisin levels and erectile dysfunction in diabetic men (irisin and erectile dysfunction in diabetic patients)

Irisin is an exercise-induced myokine that alleviates endothelial dysfunction and reduces insulin resistance in type 2 diabetes mellitus. We conducted this cross-sectional prospective study to determine the association of serum irisin levels and erectile dysfunction in type 2 diabetic patients. We compared 34 diabetic patients with erectile dysfunction with 30 diabetic patients without erectile dysfunction. In our study, serum irisin levels were found to be statistically significantly higher in diabetic patients without erectile dysfunction compared to those with erectile dysfunction (p = .016) and according to correlation analysis, irisin levels had a significantly negative correlation with the serum HbA1C value (r = -.294, p = .018). Based on the results of our study, we think that this molecule can be used in the diagnosis or treatment of erectile dysfunction in diabetic patients, if these findings are supported by larger studies.

Association Between Prediabetes and Erectile Dysfunction: A Meta-Analysis

BACKGROUND

Diabetes has been associated with the increased risk of erectile dysfunction (ED). However, previous studies evaluating the association between prediabetes and ED showed inconsistent results. We performed a meta-analysis of observational studies to systematically evaluate the above association.

METHODS

Relevant observational studies were retrieved by search of PubMed, Embase, and Web of Science databases. A random-effect model which incorporated the potential intra-study heterogeneity was used for the meta-analysis. Subgroup analyses were performed to evaluate the influences of study characteristics on the outcome.

RESULTS

Nine studies (five matched case-control studies and four cross-sectional studies) were included. Age were adjusted or matched in all of the studies. Pooled results showed that compared to men with normoglycemia, men with prediabetes were associated with higher prevalence of ED (odds ratio = 1.62, 95% confidence interval: 1.28 to 2.07, P < 0.001; I² = 78%). Subgroup analyses showed that the association was not significantly affected by definition of prediabetes, diagnostic tool for ED, or controlling of additional variables besides age (both P for subgroup difference > 0.05). However, the association between prediabetes and ED seemed to be stronger in case-control studies than that in cross-sectional studies, and in studies with younger men (mean age < 50 years) than in those with older men (mean age ≥ 50 years; both P for subgroup difference < 0.05).

CONCLUSIONS

Prediabetes is associated with higher prevalence of ED, which may be independent of age of the males and may be stronger in young men.

Epigenetic silencing of microRNA-874-3p implicates in erectile dysfunction in diabetic rats by activating the Nupr1/Chop-mediated pathway

Diabetes is a global medical problem that causes many deaths every year. Complications caused by diabetes are serious and affect patients' quality of life. Diabetes mellitus erectile dysfunction (DMED) affects more than half of male diabetes patients. In this study, we determined the role of microRNA-874-3p (miR-874-3p) and nuclear protein-1 (Nupr1) in streptozocin-induced DMED rats. Control rats received equal amount of vehicle. These rats were also injected with lentiviral vector or agomir to silence or overexpress miR-874-3p or Nupr1. Apomorphine (100 μg/kg, s.c.) was used to induce erection and time of erection was recorded. Intracavernosal and mean arterial pressure ratio (ICP/MAP) were also recorded. O^2- level and concentration of thiobarbituric acid reactive substances (TBARs) were detected using lucigenin-derived chemiluminescence method and Colorimetry. Rat cavernosum tissues were collected for subsequent experiments. Cavernosum smooth muscle cells (CSMCs) were also used for in vitro experiments. Nupr1 was found highly expressed (by RT-qPCR and Western blot analysis) in cavernosum tissues from DMED rats. Nupr1 silencing improved the ICP/MAP ratio and erection time. Nupr1 silencing also reduced CSMC apoptosis (by TUNEL assay) as well as decreased O^2- level and TBAR concentration. Nupr1 was targeted and inhibited by miR-874-3p (by luciferase activity and RNA immunoprecipitation assays), which was downregulated in DMED. miR-874-3p downregulation was due to increased methylation at the promoter region (methylation-specific PCR). miR-874-3p overexpression improved erection time and reduced apoptosis. In summary, miR-874-3p was downregulated which led to increased apoptosis and erectile dysfunction in DMED rats, through inhibition of Nupr1-mediated pathway. This study may also provide a new therapeutic direction for the treatment of DMED.

National Health and Wellness Survey exploratory cluster analysis of males 40-70 years old focused on erectile dysfunction and associated risk factors across the USA, Italy, Brazil and China

OBJECTIVES

Prior studies of erectile dysfunction (ED) tend to narrowly focus on relationships with specific comorbidities, rather than evaluating a more comprehensive array of risk factors and assessing naturalistic patterns among them. This study identifies natural clusters of male characteristics from a general population sample per country, quantifies ED dynamics in these profiles and compares profiles across the US, Italy, Brazil and China samples.

METHODS

National Health and Wellness Survey 2015 and 2016 patient-reported data on men aged 40-70 years (USA n = 15,652; Italy n = 2,521; Brazil n = 2,822; China n = 5,553) were analysed. Hierarchical agglomerative clustering identified clusters where predictors included demographics, health characteristics/behaviours, ED risk factors and provider visits in the past 6 months. Multinomial logistic regression assessed the independent utility of variables in predicting cluster membership, compared with the healthiest control cluster per country.

RESULTS

Different natural clusters were found across countries, with four clusters for the USA, Italy and China and three clusters for Brazil. Age, income, employment, health behaviours and ED risk factors predicted different cluster membership across countries. In the USA, Italy and Brazil, younger clusters were predicted by ED, unhealthy behaviours and ED risk factors. Unique cluster profiles were identified in China, with ED and ED risk factors (aside from hypertension) not predicting cluster membership, while socio-demographics and health behaviours were strongly predictive.

CONCLUSIONS

Natural cluster profiles revealed notable ED rates among adult males of age 40-70 in four different countries. Clusters were mainly predicted by unhealthy behaviours, ED risk factors and ED, regardless of level or presence of positive health characteristics and behaviours. This analysis identified meaningful subgroups of men with heightened ED risk factors, which can help healthcare providers to better recognise specific populations with the greatest need for intervention.

Effect of Nut Consumption on Erectile and Sexual Function in Healthy Males: A Secondary Outcome Analysis of the FERTINUTS Randomized Controlled Trial

Lifestyle risk factors for erectile and sexual function include smoking, excessive alcohol consumption, lack of physical activity, psychological stress, and adherence to unhealthy diets. In the present study, we evaluated the effects of mixed nuts supplementation on erectile and sexual function. Eighty-three healthy male aged 18-35 with erectile function assessment were included in this FERTINUTS study sub-analysis; a 14-week randomized, controlled, parallel feeding trial. Participants were allocated to (1) the usual Western-style diet enriched with 60 g/day of a mixture of nuts (nut group; n = 43), or (2) the usual Western-style diet avoiding nuts (control group; n = 40). At baseline and the end of the intervention, participants answered 15 questions contained in the validated International Index of Erectile Function (IIEF), and peripheral levels of nitric oxide (NO) and E-selectin were measured, as surrogated markers of erectile endothelial function. Anthropometrical characteristics, and seminogram and blood biochemical parameters did not differ between intervention groups at baseline. Compared to the control group, a significant increase in the orgasmic function (p-value = 0.037) and sexual desire (p-value = 0.040) was observed during the nut intervention. No significant differences in changes between groups were shown in peripheral concentrations of NO and E-selectin. Including nuts in a regular diet significantly improved auto-reported orgasmic function and sexual desire.

From inflammation to sexual dysfunctions: a journey through diabetes, obesity, and metabolic syndrome

Metabolic diseases are associated with chronic low-grade inflammation, which has been indicated as a potential mediator of endothelial dysfunction and cardiovascular disease. Visceral adiposity is thought to be the starting condition of the inflammatory state through the release of inflammatory cytokines, including TNF-alpha, CRP, and IL-6, which in turn promote endothelial dysfunction, endothelial expression of chemokines (IL-1) and adhesion molecules (ICAM-1, VCAM-1, and P-selectin), and the inhibition of anti-atherogenic factors (adiponectin). Obesity, metabolic diseases, and diabetes, all conditions characterized by abdominal fat, are well-recognized risk factors for sexual dysfunction in both sexes. Evidence from randomized-controlled trials supports the association between inflammatory milieau and erectile dysfunction in men suffering from metabolic diseases, whereas, in women, this has to be confirmed in further studies. A healthy lifestyle based on dietary pattern with high content of whole grain, fruit, nuts and seeds, and vegetables and low in sodium and saturated fatty acids plus regular physical activity may help to modulate the pro-inflammatory state associated with metabolic diseases and the related burden of sexual dysfunctions.

Pharmacotherapy for erectile dysfunction in diabetic males

INTRODUCTION

Numerous studies have highlighted the intimate association between erectile dysfunction (ED) and diabetes mellitus (DM). However, the true pathogenesis of ED among diabetic men has not yet been fully discovered. The treatment of ED in diabetic patients remains an interesting area of research. The last two decades have witnessed phenomenal advances in the management of ED with the efficacy of pharmacotherapy for ED in diabetic patients encouraging, especially with introduction of innovative conservative tools for treatment.

AREAS COVERED

The aim of this review is to discuss the currently available information on ED pharmacotherapy in diabetic males and provide an expert perspective on the current treatment strategies.

EXPERT OPINION

Conservative treatment remains the initial step for the treatment of ED in diabetic patients. This kind of therapy consists of different modalities including: oral treatments, intracavernosal pharmacotherapy, and evolving modalities such as soluble guanylate cyclase activators, stem cells (SCs), and alternative treatments such as herbal treatment and transdermal/topical pharmacotherapy. However, it should be noted that the currently available pharmacotherapy is still far from ideal. One hopes to witness new drugs and technologies that may revolutionize ED treatment in the future, especially in such complex cases as DM.