Conjugated linoleic acid preserves muscle mass in mice bearing the Lewis lung carcinoma, but not the B16 melanoma

Abstract

Conjugated linoleic acid (CLA), which is found in dairy products, reduces synthesis of tumor necrosis factor-alpha (TNFa), a pro-inflammatory cytokine that plays a major role in tumor-induced skeletal muscle wasting (SMW). The B16 melanoma expresses TNFa mRNA, and induced SMW with no change in muscle levels of TNFa type 1 receptor (TNFR1) protein. A diet containing .5% CLA had no effect on SMW or TNFR1 in mice bearing B16 tumors. In contrast, the Lewis lung carcinoma expresses low levels of TNFa mRNA, induced SMW, and increased muscle levels of TNFR1. A diet containing .5% CLA reduced SMW, but had no effect on muscle levels of TNFR1. We conclude that that tumor-induced SMW can occur independent of muscle levels of TNFR1. Further study is needed before CLA can be tested in persons with cancer cachexia.

c9t11‐Conjugated linoleic acid‐rich oil fails to attenuate wasting in colon‐26 tumor‐induced late‐stage cancer cachexia in male CD2F1 mice

“…McCarthy and Graves and McCarthy‐Beckett et al . reported that 0.5% of CLA in the diet preserved muscle mass in mice with Lewis Lung carcinoma, but had no effect in mice with B16 melanoma or in rats with Morris 7777 hepatoma 26, 45. Wong et al .…”

“…Numerous studies have also demonstrated the anti‐inflammatory properties of CLA 22–25. The notion that CLA has potential benefits in cancer cachexia was supported with evidence that addition of 0.5% CLA to the diet preserved muscle mass in cachectic mice bearing Lewis Lung carcinoma 26 as well as mice with colon‐26 adenocarcinoma 27. In other studies, 0.5% CLA was protective against TNF‐α‐induced 22 as well as LPS‐induced 23 wasting and the latter was associated with decreased plasma TNF‐α levels.…”

Systemic zinc redistribution and dyshomeostasis in cancer cachexia

“…A 1986 Lewis Lung Carcinoma (LLC) study showed that 21 days after tumor implantation Zn concentration in murine skeletal muscle tissue had doubled compared to the controls (p<0.01). The study did not measure muscle wasting [55], but LLC is known to cause cachexia and is commonly used as an animal model for the syndrome [56][57][58]. Interestingly, a 1987 study on hamsters with muscular dystrophy showed an 82% increase in the skeletal muscle Zn levels compared to controls (p<0.001; [59]).…”

Emerging areas of nursing science and PhD education for the 21st century: Response to commentaries

“…Carefully designed studies that incorporate biography, social-economic factors, and omics perspectives can inform understanding of risk factors and mechanisms by which genomic variation interacts dynamically with personal experience to create disease (Krieger, 2013). Using the example of cancer nursing research, O'Mara (2015) pointed out that basic research is needed to inform care; she used preclinical work on the elucidation of mechanisms of cancer cachexia (e.g., McCarthy & Graves, 2006) to support her argument. Incorporating these dimensions of the life sciences into PhD programs will inform advances in traditional areas of nursing science (e.g., symptom science and wellness) and serve as a segue to advancing nursing as the integrated biopsychosocial discipline of health.…”