Gut Microbial Dysbiosis Differs in Two Distinct Cachectic Tumor-Bearing Models Consuming the Same Diet.

The impact of cancer cachexia on the colonic microbiota is poorly characterized. This study assessed the effect of two cachectic-producing tumor types on the gut microbiota to determine if a similar dysbiosis could be found. In addition, it was determined if a diet containing an immunonutrient-rich food (walnuts) known to promote the growth of probiotic bacteria in the colon could alter the dysbiosis and slow cachexia. Male Fisher 344 rats were randomly assigned to a semi-purified diet with or without walnuts. Then, within each diet group, rats were further assigned randomly to a treatment group: tumor-bearing ad libitum fed (TB), non-tumor-bearing ad libitum fed (NTB-AL), and non-tumor-bearing group pair-fed to the TB (NTB-PF). The TB group was implanted either with the Ward colon carcinoma or MCA-induced sarcoma, both transplantable tumor lines. Fecal samples were collected after the development of cachexia, and bacteria species were identified using 16S rRNA gene analysis. Both TB groups developed cachexia but had a differently altered gut microbiome. Beta diversity was unaffected by treatment (NTB-AL, TB, and NTB-PF) regardless of tumor type but was affected by diet. Also, diet consistently changed the relative abundance of several bacteria taxa, while treatment and tumor type did not. The control diet increased the abundance of A. Anaeroplasma, while the walnut diet increased the genus Ruminococcus. There were no common fecal bacterial changes characteristic of cachexia found. Diet consistently changed the gut microbiota, but these changes were insufficient to slow the progression of cachexia, suggesting cancer cachexia is more complex than a few gut microbiota shifts.

Impact of dietary walnuts, a nutraceutical option, on circulating markers of metabolic dysregulation in a rodent cachectic tumor model.

BACKGROUND: Nutraceutical foods, like walnuts which are rich in immunonutrients, can have medicinal benefits. Dietary walnuts have been shown to slow or prevent tumor growth in mice genetically programmed to grow breast or prostate tumors. This study investigated whether walnuts could exert the same preventable effect in a transplantable carcinoma rat model. METHODS: Eighteen rats were randomly fed a diet containing walnuts (10% of food by weight), and 36 were fed a diet without walnuts (control) for 21 days. On day 22, 18 control diet rats were switched to the walnut diet. All other animals remained on their same diet. Within each diet group, 6 rats were implanted with the Ward colon carcinoma (TB), and 12 were sham-operated. Five days later, 6 sham-operated animals were weight-matched to a TB and then pair-fed for the remainder of the study. The remaining 6 sham-operated, or non-tumor-bearing rats, were ad-lib fed. RESULTS: The tissue of the walnut-eating rats showed higher omega-3 fatty acid (immunonutrient) content which did not slow or prevent tumor growth or the loss of lean and fat mass typical of this TB model. In addition, blood glucose, insulin, IGF-1, and adiponectin levels were significantly lower in the TB, demonstrating metabolic dysregulation. Again, these changes were unaltered by consuming walnuts. Plasma proteomics identified six proteins elevated in the TB, but none could be connected with the observed metabolic dysregulation. CONCLUSION: Although walnuts' rich immunonutrient content prevented tumor growth in genetically programmed mice models, there was no effect in this model.

Antioxidants Associated With Oncogenic Human Papillomavirus Infection in Women.

BACKGROUND: Human papillomavirus (HPV) infection is a major cause of cervical cancer. Studies showed the onset of HPV carcinogenesis may be induced by oxidative stress affecting the host immune system. The association between antioxidants and oncogenic HPV remains unclear. In this study, we aim to identify antioxidants associated with vaginal HPV infection in women. METHODS: The associations between the 15 antioxidants and vaginal HPV infection status (no, low-risk [LR], and high-risk [HR] HPV) were evaluated using 11 070 women who participated in the 2003-2016 National Health and Nutrition Examination Survey (NHANES). RESULTS: We identified serum albumin and 4 dietary antioxidants (vitamin A, B2, E, and folate) inversely associated with HR-HPV infection. Women with a low level of albumin (≤39 g/L) have a significantly higher risk of HR-HPV (odds ratio [OR] = 1.4, P = .009 vs >44 g/L). A Nutritional Antioxidant Score (NAS) was developed based on these 4 dietary antioxidants. The women with the lowest quartile NAS had a higher chance of HR-HPV (OR = 1.3, P = .030) and LR-HPV (OR = 1.4, P = .002) compared with the women with the highest quartile NAS. CONCLUSIONS: We identified 5 antioxidants negatively associated with vaginal HR-HPV infection in women. Our findings provide valuable insights into understanding antioxidants' impact on HPV carcinogenesis.