Long-term dietary supplementation with cystathionine improves tissue glutathione in ageing rats.

Background: Ageing is associated with decrease in tissue glutathione that can be reduced by food fortification with the amino acid cysteine. However, cysteine is not stable in solution and generates bad taste. Cystathionine, the direct precursor of cysteine, could be a valuable alternative.

Effect of slow-release β-alanine tablets on absorption kinetics and paresthesia.

Oral β-alanine (βA) doses larger than 800 mg commonly result in unpleasant sensory symptoms (paresthesia). However, the association of form (pure vs. slow-release) with side-effects has not been fully described.

A diet containing whey protein, free glutamine, and transforming growth factor-beta ameliorates nutritional outcome and intestinal mucositis during repeated chemotherapeutic challenges in rats.

Anticancer chemotherapy often induces side effects such as mucositis. Recent data suggest that a diet, Clinutren Protect (CP), containing whey proteins, glutamine, and transforming growth factor-beta (TGFbeta)-rich casein limits intestinal mucositis and improves recovery after a single methotrexate (MTX) challenge in rats. Chemotherapy consists of alternating periods of treatment and rest.

A diet containing whey protein, glutamine, and TGFbeta modulates gut protein metabolism during chemotherapy-induced mucositis in rats.

Background: Mucositis, a common side effect of chemotherapy, is characterized by compromised digestive function, barrier integrity and immune competence.

Aims: Our aim was to evaluate the impact of a specifically designed diet Clinutren Protect (CP), which contains whey proteins, TGFbeta-rich casein, and free glutamine, on mucositis in rats.

Methods: Mucositis was induced by three consecutive injections (day 0, day 1, day 2) of methotrexate (2.

Methotrexate induces intestinal mucositis and alters gut protein metabolism independently of reduced food intake.

One of the main secondary toxic side effects of antimitotic agents used to treat cancer patients is intestinal mucositis. This one is characterized by compromised digestive and absorptive functions, barrier integrity, and immune competence. At the same time, food intake is decreased, which may induce intestinal damages per se.

Chemotherapy-induced mucositis is associated with changes in proteolytic pathways.

Mucositis, a common toxic side effect of chemotherapy, is characterized by an arrest of cell proliferation and a loss of gut barrier function, which may cause treatment reduction or withdrawal. Gut integrity depends on nutritional and metabolic factors, including the balance between protein synthesis and proteolysis. The effects of methotrexate (MTX; a frequently used chemotherapeutic agent) on intestinal proteolysis and gut barrier function were investigated in rats.

Kinetics of creatine ingested as a food ingredient.

The aim of the present study was to test if the consumption of creatine incorporated in food bars modifies creatine plasma kinetics, erythrocyte retention and loss in urine and in feces when compared with its consumption in the form of an aqueous solution (AS). Seventeen healthy young men ingested 2 g creatine either in the form of AS, or incorporated in a protein (PP)- or in a beta-glucan (BG)-rich food bar. Kinetics of plasma creatine was measured for 8-h duration and urinary excretion for 24 h.

Threonine utilization for synthesis of acute phase proteins, intestinal proteins, and mucins is increased during sepsis in rats.

We hypothesized that the dietary threonine demand for the anabolic response may be increased more than that of other essential amino acids during sepsis. Using a flooding dose of either L-[1 -13C]valine or L-[U -13C]threonine, we measured valine and threonine utilization for syntheses of plasma proteins (minus albumin), and wall, mucosal, and mucin proteins of the small intestine in infected (INF; d 2 and d 6 of postinfection) and control pair-fed (PF) rats. At d 2, the protein absolute synthesis rate (ASR) of INF rats was 21% (mucins) to 41% (intestinal wall) greater than that of PF when measured using valine as tracer, and 45% (mucosa) to 113% (mucins) greater than that of PF when measured with threonine as tracer.

A comparative study of proteolysis methods for the measurement of 3-nitrotyrosine residues: enzymatic digestion versus hydrochloric acid-mediated hydrolysis.

A common approach for the quantification of 3-nitrotyrosine (NY) in routine analyses relies on the cleavage of peptide bonds in order to release the free amino acids from proteins in tissues or fluids. NY is usually monitored by either GC-MS(/MS) or LC-MS/MS techniques. Various proteolysis methods have been employed to combine digestion efficiency with prevention of artifactual nitration of tyrosine.

Effect of an enteral diet supplemented with a specific blend of amino acid on plasma and muscle protein synthesis in ICU patients.

Background & Aim: Polytrauma patients are characterized by a negative nitrogen balance and muscle wasting. Standard nutrition is relatively inefficient to improve muscle protein turnover. The aim of this study was to investigate the effect of enteral nutrition (EN) supplemented with specific amino acids on protein metabolism in polytrauma patients.

Specific amino acids increase mucin synthesis and microbiota in dextran sulfate sodium-treated rats.

During the anabolic response associated with inflammation, mucin synthesis and colonic protection may be compromised by the limited availability of specific amino acids. We therefore determined the effect of dietary amino acid supplementation on the microbiota, mucin status, and mucosal damage in dextran sulfate sodium (DSS)-treated rats. From 8 d before to 28 d after colitis induction, male Sprague-Dawley rats (10 mo old, n = 8/group) were fed a control diet supplemented or not with 2 different doses of an amino acid cocktail containing L-threonine, L-serine, L-proline, and L-cysteine.

Quantitative determination of dityrosine in milk powders by liquid chromatography coupled to tandem mass spectrometry using isotope dilution.

An analytical method to quantify dityrosine (DiTyr) in milk powder samples is presented. The assay is based on isotope dilution liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (LC-ESIMS/MS). The sample preparation entails acid hydrolysis of milk proteins followed by a solid phase-extraction (SPE) step.

Short-term dietary conjugated linoleic acid supplementation does not enhance the recovery of immunodepleted dexamethasone-treated rats.

Background: Conjugated linoleic acid (CLA) has been reported to decrease fat deposition, and increase lean body mass. This has been broadly inferred to mean that CLA alters protein turnover. However, data to test the effects of CLA on protein turnover are lacking.

Artifactual nitration controlled measurement of protein-bound 3-nitro-L-tyrosine in biological fluids and tissues by isotope dilution liquid chromatography electrospray ionization tandem mass spectrometry.

A sensitive and selective method is presented to accurately determine the level of protein-bound 3-nitro-L-tyrosine (NTyr) in rat plasma and kidney samples. This assay is based on isotope dilution liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The sample preparation entails protein precipitation, acid hydrolysis with 6 N HCl, and solid-phase extraction (using reverse and aminopropyl phase cartridges) prior to the determinative step.