Search

The study aimed to investigate the effect of oral zinc supplementation on antioxidant defenses and oxidative stress markers during chemotherapy for colorectal cancer. Twenty-four patients who had undergone surgical resection of colorectal cancer participated in this placebo-controlled, prospective randomized study. The supplementation was started in the perioperative period, in which 10 patients received 70 mg of zinc (zinc group, n = 10) and 14 patients received placebo (placebo group, n = 14) for 16 weeks. Approximately 45 days after surgical resection of tumor, all patients received a chemotherapeutic regimen (capecitabine, capecitabine combined with oxaliplatin or 5-fluorouracil). Vitamin C, vitamin E, antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), and lipid peroxidation markers malondialdehyde (MDA) and 8-isoprostane were determined before the first, second, third, and fourth chemotherapy cycles. Compared with the placebo group, the zinc group presented higher SOD values before the first, second, and fourth chemotherapy cycles and lower GPx values before the third cycle. There were no statistical differences between the study groups in vitamin C, vitamin E, MDA, or 8-isoprostane plasma values. Longitudinal analysis revealed decreased vitamin E concentration in the placebo group before the second and fourth cycles as compared with the initial values. Zinc supplementation during chemotherapy cycles increased SOD activity and maintained vitamin E concentrations. Although no effect of zinc supplementation on oxidative stress markers was observed, the increase in SOD activity indicates a production of stable free radicals, which may have a positive effect in cancer treatment.

The aim of the study was to evaluate the effect of zinc supplementation on the antibody titer and the 23-valent pneumococcal seroconversion after vaccination in patients undergoing chemotherapy for colorectal cancer. The study included 25 patients undergoing postsurgery chemotherapy for colorectal adenocarcinoma (chemo group). Subjects were assessed in the perioperative period (prevaccination), before chemotherapy (4th wk) and after 3 cycles of chemotherapy (16th wk). Thirty-two healthy volunteers (control group) were included in the study. Participants received the 23-valent pneumococcal conjugate vaccine, and capsules containing zinc (Zn) sulfate (70 mg daily) or identical placebo capsules (containing wheat starch with no added Zn) for 16 wk and were randomly allocated on one of the following groups: chemo-Zn (n = 10), chemo-placebo (n = 15), control-Zn (n = 21), and control-placebo (n = 11). The antipneumococcal antibody titer against 6 polysaccharides was analyzed by ELISA and compared using linear mixed models. The seroconversion rate was compared using Fisher's exact test. An immune response to the vaccination against pneumococcus was observed in all participants. In the 16th wk, the polysaccharide 6 concentration was lower in the chemo-Zn group [2.96 (1.74-5.03) μg/mL] compared with the Chemo-Placebo group [10.75 (5.37-21.54) μg/mL] and the seroconversion rate was lower in the chemo-placebo (36%) compared with the control-placebo (85%) (P = 0.027). Zinc supplementation did not change the antibody titer after vaccination. However, the lower seroconversion rate observed in the chemo-placebo suggests an influence of zinc in the vaccinal protection.

The objective of this study was to investigate whether serum cytokine levels correlate with depression and anxiety in colorectal cancer (CRC) patients. Twenty patients hospitalized for surgical resection of CRC were included in the study group and twenty healthy volunteers comprised the control group. Depression and anxiety were analyzed using the Hospital Anxiety and Depression Scale (HADS), and serum levels of IL-1β, IL-6, IL-8, IL-10, IL-12, TNF-α, and TGF-β were measured by Cytometric Bead Array. We found that more than half of CRC patients presented clinically significant levels of anxiety or depression, and 65% of them manifested a combination of severe anxiety and depression. CRC patients had increased serum levels of IL-1β, IL-6, IL-8, and TNF-α but lower IL-10 concentrations. Correlation analysis between HADS score and cytokine levels revealed a positive association of anxiety and/or depression with IL-1β, IL-6, IL-8, and TNF-α and a negative correlation with IL-10. These results indicate that circulating proinflammatory cytokines are involved in the pathophysiology of anxiety and depression in CRC patients. A better understanding of the molecular mechanisms involved in these psychological disorders will allow the design of therapeutic interventions that lead to an improved quality of life and overall survival of CRC patients.