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Sarcopenia is a syndrome characterized by loss of muscle mass and strength that impacts clinical outcomes and mortality in cancer patients. Although the molecular pathways involved in sarcopenia are not fully elucidated, the decrease in protein synthesis rate appears to be one of the most important events. The objective of this study was to investigate the relationship between sarcopenia and mTOR signaling pathway in patients undergoing colorectal resection surgery. Three groups of patients were assessed: 1) the control group (no cancer, no sarcopenia), 2) the cancer non-sarcopenic group and 3) the cancer sarcopenic group. All individuals were evaluated in relation to presence of sarcopenia and mTOR signaling pathway. Sarcopenia was evaluated by the combination of low muscle mass and low muscle strength, measured using computerized tomography images, and hand grip strength, respectively. Rectus abdominis muscle biopsy was performed at the time of surgery. mTOR pathway was analyzed by MILLIPLEX Map Kit Phospho/total mTOR 2-Plex Magnetic Bead Panel. Results were presented by phosphor/total mTOR ratio. Independent T test, Kruskal-Wallis test, and Dunn-Bonferroni post hoc were performed for statistical analysis and P 0.05 was considered. Thirty-six patients and five controls were evaluated. A total of 13 cancer patients (36.1%) had sarcopenia. The phospho/total mTOR ratio was different between the control group (0.167 MFI) and the cancer non-sarcopenic group (0.055 MFI) (P = 0.026) as well as between the control group (0.167 MFI) and the cancer sarcopenic group (0.0049 MFI) (P = 0.041). No difference was observed on the median phospho/total mTOR ratio between the cancer groups (P 0.05). More research is needed to extrapolate these results.

Beneficial effects of L-arginine on immune responses and bowel function have been reported. Mucositis is a side effect of chemotherapy treatment that affects approximately 40% of patients. This complication is characterized by inflammation that affects the gastrointestinal tract, increasing permeability and causing abdominal pain, nausea, vomiting, and diarrhea, which worsen the patient's nutritional status and increases morbimortality. The aim of this study was to evaluate the effect of pretreating with 2% L-arginine supplementation in water on mucositis as induced by 5-fluorouracil (5-FU; a single dose of 200 mg/kg body weight) in Swiss male mice. The effect of L-arginine on weight, intestinal permeability, morphology, and the histopathological score of the small intestine (from 0 to 12), oxidative stress, myeloperoxidase (MPO), and N-acetylglucosaminidase (NAG) activities were evaluated. Intestinal length improvement was observed, in addition to the partial recovery of the mucosal architecture. L-arginine attenuated the histopathological score and MPO activity. There was also an improvement in intestinal permeability, despite weight loss after 5-FU administration. In conclusion, L-arginine can positively impact intestinal mucositis by promoting partial mucosal recovery, reducing inflammation and improving intestinal permeability.