Is alpha-ketoisocaproyl-glutamine a suitable glutamine precursor to sustain fibroblast growth?

Effects of Alpha-Ketoglutarate on Glutamine Metabolism in Piglet Enterocytes in Vivo and in Vitro

Alpha-ketoglutarate (AKG) plays a vital part in the tricarboxylic acid cycle and is a key intermediate in the oxidation of L-glutamine (Gln). The study was to evaluate effects of AKG on Gln metabolism in vivo and in vitro. A total of twenty-one piglets were weaned at 28 days with a mean body weight (BW) of 6.0 ± 0.2 kg, and randomly divided into 3 groups: corn soybean meal based diet (CON group); the basal diet with 1% alpha-ketoglutarate (AKG treatment group); and the basal diet with 1% L-glutamine (GLN treatment group). Intestinal porcine epithelial cells-1 (IPEC-1) were incubated to investigate effects of 0.5, 2, and 3 mM AKG addition on Gln metabolism. Our results showed that there were no differences (P > 0.05) among the 3 treatments in initial BW, final BW, and average daily feed intake. However, average daily gain (P = 0.013) and gain:feed (P = 0.041) of the AKG group were greater than those of the other two groups. In comparison with the CON group, the AKG and GLN groups exhibited an improvement in villus length, mucosal thickness, and crypt depth in the jejunum of piglets. Serum concentrations of Asp, Glu, Val, Ile, Tyr, Phe, Lys, and Arg in the piglets fed the 1% AKG or Gln diet were lower than those in the CON group. Compared with the CON group, the mRNA expression of jejunal and ileal amino acid (AA) transporters in the AKG and GLN groups were significantly increased (P < 0.05). Additionally, the in vitro study showed that the addition of 0.5, 2, and 3 mM AKG dose-dependently decreased (P < 0.05) the net utilization of Gln and formulation of ammonia, Glu, Ala, and Asp by IPEC-1. In conclusion, dietary AKG supplementation, as a replacement for Gln, could improve Gln metabolism in piglet enterocytes and enhance the utilization of AA.

Nutritional enhancement of exercise performance in chronic obstructive pulmonary disease: a randomised controlled trial

BACKGROUND

Pulmonary rehabilitation is effective in improving exercise performance and health status in chronic obstructive pulmonary disease (COPD). However, the role of nutritional support in the enhancement of the benefits of exercise training has not been explored. A double blind, randomised, controlled trial of carbohydrate supplementation was undertaken in patients attending outpatient pulmonary rehabilitation.

METHODS

85 patients with COPD were randomised to receive a 570 kcal carbohydrate rich supplement or a non-nutritive placebo daily for the duration of a 7 week outpatient pulmonary rehabilitation programme. Primary outcome measures were peak and submaximal exercise performance using the shuttle walk tests. Changes in health status, body composition, muscle strength, and dietary macronutrient intake were also measured.

RESULTS

Patients in both the supplement and placebo groups increased shuttle walking performance and health status significantly. There was no statistically significant difference between treatment groups in these outcomes. Patients receiving placebo lost weight whereas supplemented patients gained weight. In well nourished patients (BMI >19 kg/m(2)) improvement in incremental shuttle performance was significantly greater in the supplemented group (mean difference between groups: 27 (95% CI 1 to 53) m, p<0.05). Increases in incremental shuttle performance correlated with increases in total carbohydrate intake.

CONCLUSIONS

When universally prescribed, carbohydrate supplementation does not enhance the rehabilitation of patients with COPD. This study suggests that exercise training results in negative energy balance that can be overcome by supplementation and that, in selected patients, this may improve the outcome of training. The finding of benefit in well nourished patients may suggest a role for nutritional supplementation beyond the treatment of weight loss in COPD.

Effects of diazepam on neutrophil (PMN) free amino acid profiles and immune functions in vitro. Metabolical and immunological consequences of L-alanyl-L-glutamine supplementation

The objective of this study was to determine the effects of diazepam, L-alanyl-L-glutamine (ala-gln) or diazepam combined with ala-gln on polymorphonuclear leukocyte (PMN) free amino acid profiles. In a parallel study the effects on PMN immune functions were also documented for the first time. The incubation of whole blood with diazepam led to significant changes in PMN free glutamine, aspartate, glutamate, ornithine, arginine, citrulline, taurine and methionine as well as branched chain and neutral amino acid concentrations. Ala-gln caused significant increases in PMN glutamine and alanine and asparagine, aspartate, glutamate, ornithine, arginine, serine and glycine profiles. Regarding PMN immune functions, diazepam significantly decreased superoxide anion (O(2)(-)) and hydrogen peroxide production (H(2)O(2)) and myeloperoxidase activity (MPO) while ala-gln significantly increased PMN immune functions. Ala-gln supplemented to diazepam largely reversed the changes in PMN amino acid profiles and PMN immune functions brought about by diazepam. Overall, diazepam or ala-gln lead to significant changes in PMN free amino acids. Important PMN immune functions also seem to be affected. In regards to the results, there is significant relevance to the pharmacological regimens which enhance the supply of diazepam or ala-gln in whole blood suggesting that considerable changes in PMN "labile free amino acid pool" occur. These regimens often follow beneficial nutritional therapy or maleficent pharmacological stress and may be one of the determinants in cell nutrition which influence PMN function. It is partially through its effect on PMN labile free amino acid pool that ala-gln supplemented to diazepam may maintain PMN immune functions in vitro.

Managing people on sip feeds in the community

Community nurses often have the difficult task of identifying and coordinating the care of under-nourished patients in the community. Studies have shown that patients who are underweight are likely to visit to their general practitioner more often, need more medication and be admitted to hospital. Nutritional sip feeds have been shown to clinically benefit underweight patients suffering from chronic conditions as well as the older people. Adapting ordinary food to meet the patient's nutritional requirements should be considered first, but sip feeds provide an additional source of nutrients when this proves insufficient. All patients on sip feeds should have a clear aim for this nutritional intervention (e.g. the healing of a pressure area) and be monitored regularly.