Influence of an ω3-fatty acid-enriched enteral diet with and without added glutamine on the metabolic response to injury in a rat model of prolonged acute catabolism

Combined effect of citrulline and lactoserum on amino acid availability in aged rats

OBJECTIVE

Age-associated sarcopenia is due to anabolic resistance to feeding. Muscle protein synthesis is improved by fast proteins (e.g., lactoserum), which increase peripheral amino acid (AA) bioavailability more rapidly than slow proteins (e.g., casein), and by citrulline. Citrulline, which limits splanchnic sequestration of AA, may more effectively increase peripheral AA bioavailability when combined with lactoserum than with casein when administered as an oral nutritional protein supplement.

METHODS

In this study, 25 fasted aged rats received a single gavage administration of lactoserum or casein 0.4 g/kg, alone or with citrulline 0.4 g/kg, and AA pharmacokinetics, glucose, insulin, triglycerides, and insulin-like growth factor 1 (IGF1) were monitored for 4 h. At 4 h, muscle protein and AA contents and protein synthesis activation were measured.

RESULTS

While lactoserum was associated with higher AA availability, citrulline exerts only limited effects on the plasma profile of AAs from the two proteins. Maximum plasma citrulline was reached earlier with casein (T90 min) than with lactoserum (T120 min). A protein x citrulline interaction was observed for some plasma and muscle AA levels with a significant activation of mechanistic target of rapamycin complex 1 (mTORC1) signaling suggesting higher anabolism with the combination of citrulline and lactoserum. Lower plasma and muscle AA levels with citrulline and lactoserum compared to lactoserum alone suggest a greater AA utilization in a context of muscle anabolic signaling activation.

CONCLUSION

Provision of a citrulline-lactoserum combination as a nutritional supplement could therefore be beneficial in terms of muscle protein balance and prevention of sarcopenia. Further studies are warranted to evaluate the efficacy of this combination.

Efficacy of prolonged elemental diet therapy after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma: A pilot prospective randomized trial (UMIN000004108)

BACKGROUNDS AND AIMS

This randomized clinical trial examined efficacy of prolonged elemental diet (ED) therapy after pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC), which often causes postoperative malnutrition leading to worsened short- and long-term outcomes.

METHODS

Thirty-nine patients with PDAC receiving PD was randomly assigned to prolonged ED group (PEDG) and control group (CG). Fat-free ED (Elental®, EA Pharma CO., Ltd., Tokyo, Japan) via tube jejunostomy was initiated on postoperative day 1 and increased to maintain with 600 kcal/day in addition to oral intake. ED was discontinued if sufficient oral intake was achieved in CG but continued during 3 postoperative months in PEDG. Primary outcome was complication necessitating readmission. Secondary outcomes were nutritional parameters, relative dose intensity (RDI) in cases of adjuvant chemotherapy, and survival outcomes.

RESULTS

Twenty patients were assigned to CG and 19 to PEDG. Cumulative post-discharge readmission rate was significantly lower in PEDG than in CG (PEDG vs CG; 12.6% vs 43.7% at 12-post-discharge-month; p = 0.018). Total calorie and ED-derived protein intakes were significantly larger in PEDG than in CG up to 3-postoperative-month but thereafter similar among groups. Lymphocyte counts were significantly increased and neutrophil-to-lymphocyte-ratio (NLR) was significantly reduced in PEDG than in CG at 2-, 3-, and 6-postoperative-month. However, other outcome measures did not differ among groups.

CONCLUSION

This trial failed to show survival benefit of prolonged ED therapy but demonstrated its favorable effect on increased lymphocyte counts, reduced NLR, and prevention of complications necessitating readmission, those which may lead to survival benefit with some modifications.

Protective action of glutamine in rats with severe acute liver failure

BACKGROUND

Severe acute liver failure (SALF) is a rare, but high-mortality, rapidly evolving syndrome that leads to hepatocyte degeneration with impaired liver function. Thioacetamide (TAA) is a known xenobiotic, which promotes the increase of the formation of reactive oxygen species. Erythroid 2-related factor 2 (Nrf2) activates the antioxidant protection of cells. Studies have evidenced the involvement of inflammatory mediators in conditions of oxidative stress.

AIM

To evaluate the antioxidant effects of glutamine on Nrf2 activation and NFκB-mediated inflammation in rats with TAA-induced IHAG.

METHODS

Male Wistar rats (n = 28) were divided into four groups: control, control+glutamine, TAA, and TAA + glutamine. Two TAA doses (400 mg/kg) were administered intraperitoneally, 8 h apart. Glutamine (25 mg/kg) was administered at 30 min, 24 h, and 36 h. At 48 h, blood was collected for liver integrity analysis [aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP)]. The liver was harvested for histology and assessment of oxidative stress [thiobarbituric acid-reactive substances (TBARS), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione (GSH), Nrf2, Kelch-like ECH-associated protein 1 (Keap1), NADPH quinone oxidoreductase1 (NQO1), superoxide dismutase (SOD)] and inflammatory process.

RESULTS

TAA caused disruption of the hepatic parenchyma, with inflammatory infiltration, massive necrosis, and ballooning degeneration. Glutamine mitigated this tissue damage, with visible regeneration of hepatic parenchyma; decreased TBARS (P < 0.001), GSH (P < 0.01), IL-1β, IL6, and TNFα levels (P <0.01) in hepatic tissue; and decreased blood levels of AST, ALT, and ALP (P <0.05). In addition, CAT, GPx, and GST activities were restored in the glutamine group (P <0.01, P <0.01, and P <0.001, respectively vs TAA alone). Glutamine increased expression of Nrf2 (P < 0.05), NQO1, and SOD (P < 0.01), as well as levels of IL-10 (P <0.001), while decreasing expression of Keap1, TLR4, NFκB (P < 0.001), COX-2 and iNOS, (P < 0.01), and reducing NO2 and NO3 levels (P < 0.05).

CONCLUSION

In the TAA experimental model of IHAG, glutamine activated the Nrf2 pathway, thus promoting antioxidant protection, and blunted the NFκB-mediated pathway, reducing inflammation.