cysteinylglycine and Disease-Models--Animal

An ultra-high performance hydrophilic interaction liquid chromatography - triple quadrupole tandem mass spectrometry method was developed for the determination of biologically important thiols, namely cysteine, homocysteine, cysteinyl-glycine, glutathione, in rat plasma. The sample preparation procedure as well as the analytical method were comprehensively optimized and subsequently validated. An optimum sample preparation protocol was based on the simple and fast derivatization of the thiols with new derivatization reagent, N-phenylmaleimide, enabling highly selective and sensitive quantification in plasma matrices. The method, characterized by favourable performance parameters and meeting the FDA criteria for biomedical analysis, was successfully applied for monitoring the concentration levels of the selected thiols in the samples from transgenic rat model for tauopathy. The study revealed significant changes in homocysteine and glutathione levels related to tauopathy while other thiols did not indicate such relationship. Indeed, these findings could play an important role in further understanding of tauopathy process in the brain. Moreover, the proposed highly effective, reliable and robust analytical protocol can be easily adapted for other thiol compounds, spreading its application range in this biomedical field.

Topics: Animals; Chemical Fractionation; Chromatography, High Pressure Liquid; Cysteine; Dipeptides; Disease Models, Animal; Glutathione; Homocysteine; Humans; Hydrophobic and Hydrophilic Interactions; Maleimides; Rats; Rats, Inbred SHR; Rats, Transgenic; Sensitivity and Specificity; Tandem Mass Spectrometry; tau Proteins; Tauopathies

PepT1, a di/tripeptide transporter, is preferentially preserved over free amino acid transporters in situations of gut stress. Therefore, our objective was to determine the impact of enterally delivered dipeptide-containing diets on indices of intestinal adaptation in neonatal piglets after intestinal resection.. Piglets (n = 25, 10 ± 1 d old) underwent an 80% jejuno-ileal resection and were provided 50% of nutritional support as TPN, and 50% as one of five, enteral test diets: 1) a control diet containing free amino acids, or the same diet but with equimolar amounts of free amino acids replaced by 2) alanyl-alanine, 3) alanyl-glutamine, 4) cysteinyl-glycine, or 5) both alanyl-alanine and cysteinyl-glycine. After 4 d of enteral feeding, indices of intestinal adaptation were assessed. Outcome measures included plasma and mucosal amino acid concentrations, morphological and histological parameters, protein synthesis, PepT1 mRNA and protein expression, and mucosal cytokine concentrations.. Intestinal length, organ weight and protein synthesis rates were not different amongst groups. All of the dipeptide-containing diets reduced pro-inflammatory cytokine concentrations in the mucosa (TNF-α, IFN-γ). The cysteinyl-glycine diet supported greater villus height compared to all other dipeptides and greater crypt depth compared to alanyl-glutamine; however, none of the dipeptide diets altered intestinal morphology compared to the free amino acid control diet.. This study showed that while there was no explicit morphological benefit of enteral dipeptides over their constituent free amino acids, there was the potential for the amelioration of intestinal inflammation by reducing pro-inflammatory cytokines. Enteral provision of dipeptides impacted intestinal adaptation, but the response was dipeptide-specific.

Topics: Animals; Dipeptides; Disease Models, Animal; Enteral Nutrition; Glutathione; Inflammation; Interferon-gamma; Intestine, Small; Organ Size; Swine; Treatment Outcome; Tumor Necrosis Factor-alpha

PepT1 transports dietary and bacterial peptides in the gut. We hypothesized that cysteinyl-glycine would ameliorate the inflammatory effect of a bacterial peptide, formyl-methionyl-leucyl-phenylalanine (fMLP), in both sow-fed and parenterally-fed piglets.. An intestinal perfusion experiment was performed in piglets (N = 12) that were sow-reared or provided with parenteral nutrition (PN) for 4 d. In each piglet, five segments of isolated intestine were perfused with five treatments including cysteine and glycine, cysteinyl-glycine, fMLP, free cysteine and glycine with fMLP, or cysteinyl-glycine with fMLP. Mucosal cytokine responses and intestinal morphology was assessed in each gut segment.. PN piglets had lower mucosal IL-10 by approximately 20% (P < 0.01). Cysteinyl-glycine lowered TNF-α response to fMLP in PN-fed animals and IFN-γ response to fMLP in both groups (P < 0.05). The free cysteine and glycine treatment reduced TNF-α in sow-fed animals (P < 0.05). fMLP affected villus height in parenterally (P < 0.05), but not sow-fed animals.. Parenteral feeding conferred a susceptibility to mucosal damage by fMLP. The dipeptide was more effective at attenuating the inflammatory response to a bacterial peptide than free amino acids. This may be due to competitive inhibition of fMLP transport or a greater efficiency of transport of dipeptides.

Topics: Animals; Cysteine; Cytokines; Dipeptides; Disease Models, Animal; Genetic Predisposition to Disease; Glycine; Inflammation; Interleukin-10; Intestinal Mucosa; Mannitol; Mucous Membrane; N-Formylmethionine Leucyl-Phenylalanine; Parenteral Nutrition; Perfusion; Peroxidase; Random Allocation; Swine; Time Factors