Cadmium may impair prostate function as measured by prostate specific antigen in semen: A cross-sectional study among European and Inuit men

Environmental Exposure to Metals, Parameters of Oxidative Stress in Blood and Prostate Cancer: Results from Two Cohorts

We studied the potential role of exposure to various metal(oid)s (As, Cd, Cr, Hg, Ni, and Pb) in prostate cancer. Two cohorts were established: the Croatian cohort, consisting of 62 cases and 30 controls, and the Serbian cohort, consisting of 41 cases and 61 controls. Blood/serum samples were collected. Levels of investigated metal(oid)s, various parameters of oxidative stress, and prostate-specific antigen (PSA) were determined in collected samples. A comparison of the measured parameters between 103 prostate cancer patients and 91 control men from both Croatian and Serbian cohorts showed significantly higher blood Hg, SOD, and GPx levels and significantly lower serum SH levels in prostate cancer patients than in controls. Correlation analyses revealed the significant relationship between certain parameters of oxidative stress and the concentrations of the measured metal(loid)s, pointing to the possible role of metal(oid)-induced oxidative stress imbalance. Furthermore, a significant inverse relationship was found between the blood Pb and the serum PSA in prostate cancer patients, but when the model was adjusted for the impacts of remaining parameters, no significant association between the serum PSA and the measured parameters was found. The results of the overall study indicate a substantial contribution of the measured metal(loid)s to the imbalance of the oxidant/antioxidant system. Although somewhat conflicting, the results of the present study point to the possible role of investigated metal(oid)s in prostate cancer, especially for Hg, since the obtained relationship was observed for both cohorts, followed by the disturbances in oxidative stress status, which were found to be correlated with Hg levels. Nevertheless, further studies in larger cohorts are warranted to explain and confirm the obtained results.

Comprehensive Review of Cadmium Toxicity Mechanisms in Male Reproduction and Therapeutic Strategies

Cadmium (Cd) has been widely studied as an environmental pollutant for many years. Numerous studies have reported that Cd exposure causes damage to the heart, liver, kidneys, and thyroid in vivo. The emerging evidence suggests that Cd exposure induces damage on male reproductive system, which is related to oxidative stress, inflammation, steroidogenesis disruption, and epigenetics. Current preclinical animal studies have confirmed a large number of proteins and intracellular signaling pathways involved in the pathological process of Cd-induced male reproductive damage and potential measures for prophylaxis and treatment, which primarily include antioxidants, anti-inflammatory agents, and essential ion supplement. However, explicit pathogenesis and effective treatments remain uncertain. This review collects data from the literatures, discusses the underlying mechanisms of Cd-induced toxicity on male reproductive function, and summarizes evidence that may provide guidance for the treatment and prevention of Cd-induced male reproductive toxicity.

The effect of seminal plasma cadmium and lead levels on semen parameters in male subjects of infertile couples: a prospective cohort study

The aim of this prospective study was to investigate whether there is a relationship between seminal plasma cadmium (Cd) and lead (Pb) levels and semen parameters in male partners of infertile couples. Two hundred fifty one (251) men recruited with no history of occupational exposure to toxic metals. After semen analysis, seminal Cd and Pb levels were measured using atomic absorption spectrometry. Cadmium levels in men with hypospermia was significantly higher than men with normal semen volume (p = .049). In contrast, there was no statistically significant difference in median seminal Pb levels between men with hypospermia and men with normal semen volume (p = .13). There was no statistically significant association between seminal plasma Cd and Pb levels sperm concentration, motility, morphology and total progressively motile sperm count. These findings suggest that environmental Cd exposure may contribute to low semen volume in male partners of infertile couples.IMPACT STATEMENTWhat is already known on this subject? Toxic metals may adversely affect both male and female reproductive system.What the results of this study add? Seminal plasma cadmium levels in men with hypospermia were statistically significantly higher than men with normal semen volume.What the implications are of these findings for clinical practice and/or further research? Patients should be informed about possible adverse effects of toxic metals.

Association between cadmium and androgen receptor protein expression differs in prostate tumors of African American and European American men

Cadmium is a known carcinogen that has been implicated in prostate cancer, but how it affects prostate carcinogenesis in humans remains unclear. Evidence from basic science suggests that cadmium can bind to the androgen receptor causing endocrine disruption. The androgen receptor is required for normal prostate development and is the key driver of prostate cancer progression. In this study, we examined the association between cadmium content and androgen receptor protein expression in prostate cancer tissue of African American (N = 22) and European American (N = 30) men. Although neither overall tumor cadmium content (log transformed) nor androgen receptor protein expression level differed by race, we observed a race-cadmium interaction with regard to androgen receptor expression (P = 0.003) even after accounting for age at prostatectomy, smoking history, and Gleason score. African American men had a significant positive correlation between tumor tissue cadmium content and androgen receptor expression (Pearson correlation = 0.52, P = 0.013), while European Americans showed a non-significant negative correlation between the two (Pearson correlation = -0.19, P = 0.31). These results were unchanged after further accounting for tissue zinc content or dietary zinc or selenium intake. African American cases with high-cadmium content (>median) in tumor tissue had more than double the androgen receptor expression (0.021 vs. 0.008, P = 0.014) of African American men with low-cadmium level. No difference in androgen receptor expression was observed in European Americans by cadmium level (high 0.015 vs. low 0.011, P = 0.30). Larger studies are needed to confirm these results and if upheld, determine the biologic mechanism by which cadmium increases androgen receptor protein expression in a race-dependent manner. Our results suggest that cadmium may play a role in race disparities observed in prostate cancer.

Androgen Receptor Genotype in Humans and Susceptibility to Endocrine Disruptors

Although animal studies have raised concern that the influence of endocrine-disrupting compounds would obstruct the development of the male reproductive system, in general, exposure levels far above those found in humans have been needed to induce reproductive toxicity in animal models. Human data are inconclusive and have evoked the question whether endocrine-disrupting compounds can have any impact on hormonal function and thus health consequences when natural hormones are present. Indeed, many contaminants with hormone-like activity are much less potent than endogenous hormones themselves: 17β-oestradiol was, for instance, estimated to be 17,000 times more potent than o,p'-DDT. However, humans are exposed to a multitude of agents, and when present in sufficient number and concentration, they might in principle act collected on the actions of endogenous hormones. Whether such effects will be physiologically relevant is still not known. Nevertheless, in the worst-case scenario, there are no threshold levels below which there are no effects at all, and one target molecule is the androgen receptor. This mini review focuses on the androgen receptor gene, its link with classical endocrine disruptors and smoking, and how common genetic variants in the androgen receptor gene may influence physiological outcomes.