Cancer is a wasting disease and cancer patients are at a high risk of malnutrition. Due to the possibility that parenteral nutrition may stimulate tumor growth and proliferation, parenteral nutritional support for tumor patients is controversial . However, it is clear that nutritional support is important for patients undergoing surgery or receiving chemotherapy, radiation therapy and other cancer treatments, which also helps maintain the body’s immunity. Appropriate perioperative nutritional support is important in improving the nutritional status of the body, maintaining the structure and function of the organs, reducing the incidence of surgical mortality and postoperative complications, and improving the patient’s quality of life . It also provides a good platform for the body to withstand the next round of treatment . Our clinical trial suggests that a standard calorie parenteral nutrition program such as the one used in the current trial can effectively maintain the nutritional status of patients post surgery.
ω-3 fish oil is made up of the fatty acids EPA and DHA, which the body itself can only synthesize a very small amount. EPA and DHA can increase the amount of phospholipid omega-3 in cell membranes, while reducing inflammatory eicosane generation by increasing the amount of non-inflammatory eicosane competing in the arachidonic acid synthetic pathway. The release of antibodies and the phagocytic activity of macrophages are subsequently enhanced, thereby inhibiting the release of pro-inflammatory cytokines IL-1, IL-6 and TNF-α. As shown in our study in Table 4, IL-6 and TNF-α were only increased in the control group postoperatively, but not in the intervention group. The use of omega-3 fat emulsion can also increase the release of anti- inflammatory cytokines IL-10, IL- 13, and TGB-β, thus blocking the body’s excessive inflammatory response and reducing the incidence of Systemic Inflammatory Response Syndrome (SIRS) and Multiple Organ Dysfunction Syndrome (MODS). The mortality of patients was therefore decreased and the prognosis of patients improved after major abdominal surgery, and in patients with peritonitis and abdominal sepsis and other conditions . In our study, we found a significantly higher chance of postoperative infections in the control group (Table 6), which is consistent with the higher postoperative WBC levels in the control group. Together, our data suggests that ω-3 fish oil fat emulsion supplementation can reduce the body’s pro-inflammatory reaction after surgery, contributing to lower incidences of postoperative infection and aiding in the early recovery of patients.
Current research on the effects of ω-3 fatty acids on immune function revolves around their effects on cytokines, adhesion molecules, differentiation antigen receptor expression, free radicals, peroxides, antibody production, lymphocyte proliferation, antigen-presenting cell function and natural killer cell cytotoxicity . The role of ω-3 fatty acids in regulating the levels of these immune factors in the body can therefore lead to enhanced immune function . Studies also suggest that ω-3 fatty acids may alter the lipid environment of membrane micro-lipids, shifting the receptor protein to a non-functional region, thereby generating immune-modulatory effects . ω-3 fatty acids can also play its role in the immune system by modulating dendritic cells (DCs) .
Alanine aminotransferase and aspartate aminotransferase were increased in both groups 6 days post surgery, but the increase was to a lesser extent in the intervention group, which stayed within the normal range. This indicates that ω-3 fish oil fat emulsion may decrease the amount of hepatic damage resulting from gastric cancer surgery. This may be related to the role of ω-3 fatty acids in increasing liver blood perfusion and reducing intestinal bacterial translocation ; as well as their ability to reduce the release of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and platelet activating factor, resulting in the inhibition of L-1β, IL-2 and TNF-α mRNA expression, thereby blocking the excessive inflammatory response to protect the function of vital organs .
In conclusion, ω-3 fish oil fat emulsion-based parenteral nutrition promotes the recovery of the immune function, alleviates inflammation and reduces the rate of complications in patients with surgically resected gastric tumors. However, our findings await confirmation from future prospective controlled studies on a larger patient population.