Prospective Cohort Study

Selenium is a micronutrient that is essential for the proper functioning of all organisms. Studies on the functions of selenium are rapidly developing. This element is a cofactor of many enzymes, for example, glutathione peroxidase or thioredoxin reductase. Insufficient supplementation of this element results in the increased risk of developing many chronic degenerative diseases. Selenium is important for the protection against oxidative stress, demonstrating the highest activity as a free radical scavenger and anti-cancer agent. In food, it is present in organic forms, as exemplified by selenomethionine and selenocysteine. In dietary supplementation, the inorganic forms of selenium (selenite and selenate) are used. Organic compounds are more easily absorbed by human organisms in comparison with inorganic compounds. Currently, selenium is considered an essential trace element of fundamental importance for human health. Extreme selenium deficiencies are widespread among people all over the world. Therefore, it is essential to supplement the deficiency of this micronutrient with selenium-enriched food or yeast cell biomass in the diet.

https://www.mdpi.com/1420-3049/24/7/1298/pdf

Selenium–Fascinating Microelement, Properties and Sources in Food

Several studies suggest that type 2 diabetes mellitus (T2DM) is often associated with male hypogonadism. Despite the well-known link, the role of testosterone replacement therapy (TRT) in T2DM has not been completely clarified. The aim of the present study was to analyse systematically the relationship between androgen levels and T2DM by reviewing and meta-analysing available prospective and cross-sectional studies. In addition, a specific meta-analysis on the metabolic effects of TRT in available randomized clinical trials (RCTs) was performed. An extensive Medline search was performed including the following words: 'testosterone', 'type 2 diabetes mellitus' and 'males'. Of 742 retrieved articles, 37 were included in the study. In particular 28, 5 and 3 were cross-sectional, longitudinal and interventional studies, respectively. A further unpublished RCT was retrieved from http://www.clinicaltrials.gov. T2DM patients showed significantly lower testosterone plasma levels in comparison with non-diabetic individuals. Similar results were obtained when T2DM subjects with and without erectile dysfunction were analysed separately. Meta-regression analysis demonstrated that ageing reduced, while obesity increased, these differences. However, in a multiple regression model, after adjusting for age and body mass index (BMI), T2DM was still associated with lower total testosterone (TT) levels (adjusted r = -0.568; p < 0.0001). Analysis of longitudinal studies demonstrated that baseline TT was significantly lower among patients with incident diabetes in comparison with controls (HR = -2.08[-3.57;-0.59]; p < 0.001). Combining the results of RCTs, TRT was associated with a significant reduction in fasting plasma glucose, HbA1c, fat mass and triglycerides. Conversely, no significant difference was observed for total and high-density lipoprotein cholesterol, blood pressure and BMI. The meta-analysis of the available cross-sectional data suggests that T2DM can be considered independently associated with male hypogonadism. Although only few RCTs have been reported, TRT seems to improve glycometabolic control as well as fat mass in T2DM subjects.

Type 2 diabetes mellitus and testosterone: a meta-analysis study

Selenium supplementation in the prevention of coronavirus infections (COVID-19).

Over the past two decades, public health has focused on the identification of environmental chemical factors that are able to adversely affect hormonal function, known as endocrine disruptors (EDs). EDs mimic naturally occurring hormones like estrogens and androgens which can in turn interfere with the endocrine system. As a consequence, EDs affect human reproduction as well as post and pre-natal development. In fact, infants can be affected already at prenatal level due to maternal exposure to EDs. In particular, great attention has been given to those chemicals, or their metabolites, that have estrogenic properties or antagonistic effects on the activity of androgen or even inhibiting their production. These compounds have therefore the potential of interfering with important physiological processes, such as masculinization, morphological development of the urogenital system and secondary sexual traits. Animal and in vitro studies have supported the conclusion that endocrine-disrupting chemicals affect the hormone-dependent pathways responsible for male gonadal development, either through direct interaction with hormone receptors or via epigenetic and cell-cycle regulatory modes of action. In human populations, epidemiological studies have reported an overall decline of male fertility and an increased incidence of diseases or congenital malformations of the male reproductive system. The majority of studies point towards an association between exposure to EDs and male and/or female reproductive system disorders, such as infertility, endometriosis, breast cancer, testicular cancer, poor sperm quality and/or function. Despite promising discoveries, a causal relationship between the reproductive disorders and exposure to specific toxicants has yet to be established, due to the complexity of the clinical protocols used, the degree of occupational or environmental exposure, the determination of the variables measured and the sample size of the subjects examined. Despite the lack of consistency in the results of so many studies investigating endocrine-disrupting properties of many different classes of chemicals, the overall conclusion points toward a positive association between exposure to EDs and reproductive system. Future studies should focus on a uniform systems to examine human populations with regard to the exposure to specific EDs and the direct effect on the reproductive system.

/pdf/water-and-soil-pollution-as-determinant-of-water-and-food-2kakl4gf16.pdf

Water and soil pollution as determinant of water and food quality/contamination and its impact on male fertility.

Selenium is an essential trace element in the human body and plays an important role in the body via selenoprotein, which contains selenium. Selenoproteins (glutathione peroxidase, thioredoxin reductase, methionine sulfoxide reductase1 and endoplasmic reticulum-selenoproteins, etc.) have antioxidant effects and are involved in regulating antioxidant activities. Aging is an inevitable process and is always accompanied by aging-related diseases. Reactive oxygen species are important initial factors in aging and aging-related diseases. Selenium contributes to the alleviation of reduced reactive oxygen species-mediated inflammation, reduced DNA damage and prolonged telomere length and thereby plays roles in fighting aging and preventing aging-related diseases. In the elderly, aging-related diseases include neuropsychiatric diseases, tumors, cardiovascular diseases, and skin aging, among others. Selenium supplementation is an important strategy for anti-aging and the prevention of aging-related diseases and is of great significance for the elderly. However, with the accumulation of related research, selenium supplementation does not necessarily contribute to the prevention of aging and aging-related diseases. It is believed that a low level of selenium is beneficial to the human body. Thus, the effect of selenium on human aging and aging-related diseases is still controversial. This paper reviews the research progress and objective role of selenium in aging and aging-related diseases.

Selenium, aging and aging-related diseases.

Chemotherapy is an important cancer treatment method. Tumor chemotherapy resistance is one of the main factors leading to tumor progression. Like other malignancies, bladder cancer, especially muscle-invasive bladder cancer, is prone to chemotherapy resistance. Additionally, only approximately 50% of muscle-invasive bladder cancer responds to cisplatin-based chemotherapy. miRNAs are a class of small, endogenous, noncoding RNAs that regulate gene expression at the posttranscriptional level, which results in the inhibition of translation or the degradation of mRNA. In the study of miRNAs and cancer, including gastric cancer, prostate cancer, liver cancer, and colorectal cancer, it has been found that miRNAs can regulate the expression of genes related to tumor resistance, thereby promoting the progression of tumors. In bladder cancer, miRNAs are also closely related to chemotherapy resistance, suggesting that miRNAs can be a new therapeutic target for the chemotherapy resistance of bladder cancer. Therefore, understanding the mechanisms of miRNAs in the chemotherapy resistance of bladder cancer is an important foundation for restoring the chemotherapy sensitivity of bladder cancer and improving the efficacy of chemotherapy and patient survival. In this article, we review the role of miRNAs in the development of chemotherapy-resistant bladder cancer and the various resistance mechanisms that involve apoptosis, the cell cycle, epithelial-mesenchymal transition (EMT), and cancer stem cells (CSCs).

/pdf/mirnas-a-promising-target-in-the-chemoresistance-of-bladder-4czrv9tqn2.pdf

miRNAs: A Promising Target in the Chemoresistance of Bladder Cancer

Introduction Several studies have explored the association between outdoor air pollution and semen quality. However, the results were inconsistent. We performed the current meta-analysis to evaluate the role of outdoor air pollution in semen quality. Material and Methods. Databases including PubMed, Web of Science, and Embase were searched to identify relevant studies. Relative data in participants under higher exposure and lower exposure to air pollution were extracted. Pooled weighted mean differences (WMDs) with corresponding 95% confidence intervals (CIs) were utilized to assess the effects of outdoor air pollution on semen quality. In addition, trial sequential analyses (TSAs) were performed to obtain a more comprehensive assessment of analyses. Results A total of 11 studies with 4562 males were enrolled in the current meta-analysis. Higher air pollution levels were associated with significant decreases in semen volume (WMD: -0.16, 95% CI: -0.27 to -0.05), sperm concentration (WMD: -5.52, 95% CI: -9.88 to -1.16), progressive motility (WMD: -6.23, 95% CI: -11.64 to -0.81), total motility (WMD: -7.65, 95% CI: -14.09 to -1.20), and normal sperm morphology rate (WMD: -3.71, 95% CI: -5.59 to -1.82). In addition, the DNA fragmentation index significantly increased (WMD: 4.11, 95% CI: 1.94 to 6.29). Conclusions Air pollution is associated with decreased semen volume, sperm concentration, motility, and normal morphology rate.

/pdf/impacts-of-outdoor-air-pollution-on-human-semen-quality-a-4ylq9yh968.pdf

Impacts of Outdoor Air Pollution on Human Semen Quality: A Meta-Analysis and Systematic Review.

Knowledge is limited about the lifetime risk of chronic pelvic pain syndrome (CPPS) occurrence in Chinese middle-aged males and the prognosis of CPPS patients with and without treatment. Noninstitutionalized Chinese males aged 40 to 81 years were enrolled in this study from a total of 76 local communities across 30 provinces of China. Information about the occurrence of CPPS, symptom relief, and previous treatment was collected. Based on completed answers to specific questions about self-reported and physician-diagnosed CPPS, the lifetime risk of CPPS occurrence was 25.3% (1,091 out of 4,315) in Chinese males aged 40 to 81 years. Over 77% of patients with CPPS had received treatment. The symptom relief rate was not significantly different between the treatment (57.3%, 142/248) and nontreatment (50.1%, 422/843) groups. Regardless of whether patients had received medical treatment, engagement in sedentary work and regular alcohol consumption had a significant negative influence, while marriage had a positive influence, on the prognosis of CPPS. A good prognosis could be achieved without treatment for some cases of CPPS, while others required a timely symptom-orientated treatment using adequate medications combined with lifestyle adjustment and follow-up.

https://journals.sagepub.com/doi/pdf/10.1177/1557988319865380

The Lifetime Risk and Prognosis of Chronic Prostatitis/Chronic Pelvic Pain Syndrome in the Middle-Aged Chinese Males:

Objective We performed this meta-analysis to assess serum testosterone changes in adult males with Type 2 diabetes (T2DM). Methods PubMed, Embase, Web of Science, and Cochrane Library were searched to identify qualified studies. Pooled weighted mean differences (WMDs) with 95% confidence intervals (CIs) were utilized to test the changes of total testosterone (TT), free testosterone (FT) and sex hormone-binding globulin (SHBG) in patients with T2DM. Besides, trial sequential analysis was used to verify the pooled results. Results A total of 56 studies were enrolled in our meta-analysis. Meta-analyses of the cross-sectional studies showed that patients with T2DM has significant decreases in TT (WMD: -2.98, 95%CI: -3.48 to -2.47), FT (WMD: -32.82, 95%CI: -39.70 to -25.95) and SHBG (WMD: -2.47, 95%CI: -3.93 to -1.02). In terms of the prospective studies, our results showed decreases in TT (WMD: -2.35, 95%CI: -3.24 to -1.46), FT (WMD: -25.96, 95%CI: -83.98 to 32.05), and SHBG (WMD: -10.06, 95%CI: -13.29 to -6.84) in patients with T2DM. By trial sequential analyses, the findings in current meta-analysis were based on reliable evidence. Conclusion Our results indicate that patients with T2DM have lower serum TT, FT, and SHBG levels.

Zhonglin Cai

Papers

Selenium, aging and aging-related diseases.

miRNAs: A Promising Target in the Chemoresistance of Bladder Cancer

Impacts of Outdoor Air Pollution on Human Semen Quality: A Meta-Analysis and Systematic Review.

The Lifetime Risk and Prognosis of Chronic Prostatitis/Chronic Pelvic Pain Syndrome in the Middle-Aged Chinese Males:

Association between testosterone with type 2 diabetes in adult males, a meta-analysis and trial sequential analysis.