Growth inhibition of subcutaneously transplanted hepatomas without cachexia by alteration of the dietary arginine-methionine balance

Nutrition Modulation of Cachexia/Proteolysis

Cachexia represents progressive wasting of muscle and adipose tissue and is associated with increased morbidity and mortality. Although anorexia usually accompanies cachexia, cachexia rarely responds to increased food intake alone. Our knowledge of the underlying mechanisms responsible for cachexia remains incomplete. However, most states of cachexia are associated with underlying inflammatory processes and/or cancer. These processes activate protein degradation and lipolytic pathways, resulting in tissue loss. In this article, we briefly review the pathophysiology of cachexia and discuss the role of specific nutrient supplements for the treatment of cachexia. The branched chain amino acid leucine, the leucine metabolite beta-hydroxy-beta-methylbutyrate, arginine, glutamine, omega-3 long chain fatty acids, conjugated linoleic acid, and polyphenols have demonstrated some efficacy in animal and/or human studies. Optimal treatment for cachexia is likely aimed at maximizing muscle and adipose synthesis while minimizing degradation.

Effect of protein hydrolysates from germinated soybean on cancerous cells of the human cervix: an in vitro study

Consumption of soybeans can reduce the risk of different types of cancer. Little is known about the effect of germination on the anticancer properties of soya. This study was done to determine if germination improves the anticancer properties of soybean protein through generation of amino acids or bioactive peptides. Soybean was germinated for 0, 2, 3, 4, 5, and 6 days and proteins were isolated from the seeds. Isolates with and without ethanol-soluble phytochemicals were hydrolyzed with digestive enzymes and their effect on growth in HeLa and C-33 (epidermoid cervical carcinoma) and HaCaT (non-cancerous human keratinocytes) cells were evaluated with the Alamar Blue method. Germination induced degradation of the alpha and alpha' fractions of beta-conglycinin and acid fraction of glycinin, generating low molecular weight peptides. Degrees of hydrolysis ranged from 73-77%. Hydrolysates inhibited the growth of HeLa cells and C-33 at concentrations exceeding 1.25 mg/ml. Major inhibition was observed with the hydrolysate germinated for 2 days and containing ethanolsoluble phytochemicals (IC(50) 2.15 and 2.27 mg/ml for HeLa and C-33, respectively). Interestingly, hydrolysate cytoxicity for normal cells was minimal in comparison to cancer cells.

Pros and cons of L-arginine supplementation in disease

The amino acid arginine and one of its metabolites NO have gathered broad attention in the last decade. Although arginine is regarded as a conditionally essential amino acid in disease, L-arginine supplementation in severe illness has not found its way into clinical practice. This might be due to the invalid interpretation of results from studies with immune-enhancing diets containing L-arginine amongst other pharmaconutrients. However, not much attention is given to research using L-arginine as a monotherapy and the possibility of the alternative hypothesis: that L-arginine supplementation is beneficial in disease. The present review will discuss data from studies in healthy and diseased animals and patients with monotherapy of L-arginine to come to an objective overview of positive and negative aspects of L-arginine supplementation in disease with special emphasis on sepsis, cancer, liver failure and wound healing.

Impact of nutrition support on treatment outcome in patients with locally advanced head and neck squamous cell cancer treated with definitive radiotherapy: A secondary analysis of RTOG trial 90-03

BACKGROUND

The aim was to evaluate the relationship between nutrition support (NS) on host toxicity and cancer outcome in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) undergoing definitive radiotherapy (XRT).

METHODS

We performed a secondary analysis of Radiation Therapy Oncology Group (RTOG) 90-03, a prospective randomized trial evaluating four definitive XRT fractionation schedules in patients with locally advanced HNSCC, which prospectively collected data on NS delivered before treatment (BNS), during treatment (TNS), and after definitive XRT. NS data and pretreatment characteristics of the 1073 evaluable patients were analyzed against therapy toxicity and outcome.

RESULTS

Patients receiving BNS experienced significantly less weight loss by the end of treatment and less grade 3 to 4 mucositis than patients not receiving BNS. However, patients receiving BNS had a poorer 5-year actuarial locoregional control rate than patients receiving TNS or no NS (29%, 55%, and 57%, respectively, p < .0001) and a poorer 5-year overall survival rate (16%, 36%, and 49%, respectively, p < .0001). Patients receiving BNS were significantly more likely to have a higher T classification, N status, and overall American Joint Committee on Cancer (AJCC) stage and initial presentation with greater pretreatment weight loss, and a poorer Karnofsky Performance Status (KPS) than patients not receiving BNS. After adjusting for the impact of these prognostic factors through a recursive partition analysis, a multivariate analysis with a stratified Cox model found that BNS was still a highly significant independent prognostic factor for increased locoregional failure (hazards ratio [HR], 1.47; 95% confidence interval [CI], 1.21-1.79; p < .0001) and death (HR, 1.41; 95% CI, 1.19-1.67; p < .0001).

CONCLUSION

In this study, the largest prospective evaluation of nutrition data in treated patients with cancer, BNS was associated with inferior treatment outcome in the patients with HNSCC undergoing XRT. These results should be considered hypothesis generating and encourage prospective clinical research and identification of the mechanisms underlying this finding.

The influence of labile dietary methyl donors on the arginine requirement of young broiler chicks

Two experiments were conducted with Ross x Ross boiler chicks in battery brooders from 1 to 14 d of age to determine the influence of dietary methyl donors on the Arg requirement of young broiler chicks. Experiment 1 had a 6 x 2 factorial design, with six levels of Arg supplementation (0, 0.1, 0.2, 0.3, 0.4, and 0.5%) and two levels of DL-Met supplementation (0 and 0.2% of the diet). The design of Experiment 2 was identical to Experiment 1, except that a second source of labile methyl groups was added, 0.2% betaine (6 x 3 factorial arrangement). Both experiments had four replicate pens of 10 chicks each per treatment. The basal diet was based on corn (34.52%), whey (26.96%), corn gluten meal (16.53%), soybean meal (11.74%), and poultry fat (23% CP and 3.20 kcal/g of ME). At 14 d, three chicks per replicate were randomly killed, and breast muscle was collected and pooled for creatine analysis. The broken-line linear model was used to estimate the Arg requirements of the chicks. There were no differences in Arg requirements due to methyl source so the data were pooled. In Experiment 1, the Arg requirements were 1.17 +/- 0.04% for gain, 1.23 +/- 0.03% for feed conversion ratio (FCR), and 1.18 +/- 0.03% for muscle creatine, when the diet contained 0.45 or 0.65% Met. In Experiment 2, the Arg requirements were 1.20 +/- 0.05% for gain, 1.23 +/- 0.03% for FCR, and 1.26 +/- 0.02% for muscle creatine. There was no apparent difference in the Arg requirement of young broilers due to methyl donor supplementation.

Can dietary methionine restriction increase the effectiveness of chemotherapy in treatment of advanced cancer?

Most metastatic tumors, such as those originating in the prostate, lung, and gastrointestinal tract, respond poorly to conventional chemotherapy. Novel treatment strategies for advanced cancer are therefore desperately needed. Dietary restriction of the essential amino acid methionine offers promise as such a strategy, either alone or in combination with chemotherapy or other treatments. Numerous in vitro and animal studies demonstrate the effectiveness of dietary methionine restriction in inhibiting growth and eventually causing death of cancer cells. In contrast, normal host tissues are relatively resistant to methionine restriction. These preclinical observations led to a phase I clinical trial of dietary methionine restriction for adults with advanced cancer. Preliminary findings from this trial indicate that dietary methionine restriction is safe and feasible for the treatment of patients with advanced cancer. In addition, the trial has yielded some preliminary evidence of antitumor activity. One patient with hormone-independent prostate cancer experienced a 25% reduction in serum prostate-specific antigen (PSA) after 12 weeks on the diet, and a second patient with renal cell cancer experienced an objective radiographic response. The possibility that methionine restriction may act synergistically with other cancer treatments such as chemotherapy is being explored. Findings to date support further investigation of dietary methionine restriction as a novel treatment strategy for advanced cancer.