Dynamic changes of serum trace elements following cardiac surgery: A systematic review and meta-analysis.

BACKGROUND: Cardiac surgeries are known to induce an inflammatory response. Besides, dietary factors such as trace elements contribute to promoting cardiovascular health by maintaining oxidative balance. Here we systematically review the literature about alterations in serum concentrations of zinc (Zn), copper (Cu), and selenium (Se) in response to cardiac surgeries. METHODS: A systematic search was performed on databases until the end of December 2022. Studies assessing the changes of mentioned elements in adult patients undergoing cardiac surgery were included. Changes in the means and standard deviations of the elements before and after the cardiac surgery were utilized as desired effect sizes. RESULTS: Among 1252 records found in the primary search, 23 and 21 articles were included in the systematic review and meta-analysis respectively. Seventeen studies evaluated the changes in serum Zn and Cu levels, and fifteen studies assessed Se levels. According to the results of quantitative analysis, Zn, Cu, and Se concentrations, one day after the surgery were significantly lower than preoperative values (WMD for Zn: 4.64 µmol/L [3.57-5.72], WMD for Cu: 1.62 µmol/L [0.52-2.72], and WMD for Se: 0.1 µmol/L [0.03-0.16]). The concentration of trace elements recovered gradually during the first-week post-operation and reached preoperative levels or even higher. CONCLUSION: Serum trace elements dropped significantly soon after the cardiac surgery, but they reached their baseline levels mostly during the first week after the surgery. Future studies are warranted to elucidate the impact of alterations in serum concentration of trace elements on the outcomes and complications of open-heart surgeries.

COVID-19 and Selenium Deficiency: a Systematic Review.

Several studies have indicated that selenium deficiency may be detrimental in the context of various viral disorders, and in the case of COVID-19, several studies have reported heterogeneous results concerning the association of selenium deficiency with the severity of disease. To summarize the available data surrounding the association of body selenium levels with the outcomes of COVID-19, a systematic search was performed in the Medline database (PubMed), Scopus, Cochrane Library, Embase, and Web of Science using keywords including "SARS-CoV-2," "COVID-19," and "selenium," Studies evaluating the association of COVID-19 with body selenium levels were included. Among 1,862 articles viewed in the database search, 10 articles were included after title, abstract, and full-text review. One study was further included after searching the literature again for any newly published articles. Out of 11 included studies, 10 studies measured serum selenium level, and one study investigated urinary selenium level. Three of 10 studies measured serum SELENOP level as well as selenium level. Glutathione peroxidase-3 level in serum was also assessed in one study. The reported outcomes were severity, mortality, and risk of COVID-19. Nine studies indicated that a lower serum selenium level is associated with worse outcomes. Two studies reported no significant association between serum selenium level and COVID-19. In one study, urinary selenium level was reported to be higher in severe and fatal cases compared to non-severe and recovered patients, respectively. In most cases, selenium deficiency was associated with worse outcomes, and selenium levels in COVID-19 patients were lower than in healthy individuals. Thus, it could be concluded that cautious selenium supplementation in COVID-19 patients may be helpful to prevent disease progression. However, randomized clinical trials are needed to confirm this.