Effects of nitric oxide synthase inhibition on glutamine action in a bacterial translocation model

Abstract

Glutamine may be a precursor for NO synthesis, which may play a crucial role in bacterial translocation (BT). The goal of the present study was to investigate the potential effects of glutamine on BT and the immunological response in an experimental model of NO synthase inhibition by NG-nitro-L-arginine methyl ester (l-NAME). Mice were randomly assigned to four groups: sham; intestinal obstruction (IO); IO+500 mg/kg per d glutamine (GLN); IO+GLN plus 10 mg/kg per d l-NAME (GLN/LN). The groups were pretreated for 7 d. BT was induced by ileal ligation and was assessed 18 h later by measuring the radioactivity of 99mTc-Escherichia coli in the blood and organs. Mucosal damage was determined using a histological analysis. Intestinal permeability (IP) was assessed by measuring the levels of 99mTc-diethylenetriaminepentaacetic acid in the blood at 4, 8 and 18 h after surgery. IgA and cytokine concentrations were determined by ELISA in the intestinal fluid and plasma, respectively. BT was increased in the GLN/LN and IO groups than in the GLN and sham groups. IP and intestinal mucosa structure of the sham, GLN and GLN/LN groups were similar. The GLN group had the highest levels of interferon-γ, while IL-10 and secretory IgA levels were higher than those of the IO group but similar to those of the GLN/LN group. The present results suggest that effects of the glutamine pathway on BT were mediated by NO. The latter also interferes with the pro-inflammatory systemic immunological response. On the other hand, IP integrity preserved by the use of glutamine is independent of NO.

Protective effect of β-glucan and glutamine on intestinal and immunological damage in mice induced by cytarabine (Ara-C)

“…Several studies have shown that β-glucan is very good at improving immunity, and glutamine has an important role in cell-mediated immunity and the integrity of the intestinal mucosa (Sandvik et al 2007, Santos et al 2014, Wang & Ellis 2014, Chaudhry et al 2016, Li et al 2006 . In this report, we demonstrate for the first time the benefits of their association.…”

“…Glutamine is an essential amino acid, it is the most abundant free substance in the plasma and tissue fluids (Bertrand et al 2013, Chaudhry et al 2016. This amino acid is required for specific biochemical processes such as metabolic functions in the immune system and in the intestinal functions (Santos et al, 2014). Glutamine is a precursor to protein synthesis and a preferred energy source for fast proliferation of mucosal cells and cells of the immune system (Bertrand et al 2013).…”

“…In catabolic states the increased demand for glutamine happen (Bertrand et al, 2013, Santos et al, 2014. This amino acid is released from muscle tissue in order to nourish and repair the enterocytes, if this demand is not enough, it is necessary endogenous supply .…”

“…This amino acid is released from muscle tissue in order to nourish and repair the enterocytes, if this demand is not enough, it is necessary endogenous supply . Various studies have demonstrated that supplemented glutamine can maintain the morphology and functions of the intestines, in addition to promoting the enhance of immune system (Ren et al 2014, Santos et al 2014, Chaudhry et al 2016.…”

Glutamine decreases intestinal mucosal injury in a rat model of intestinal ischemia-reperfusion by downregulating HMGB1 and inflammatory cytokine expression

“…Notably, plasma D-lactate levels have been found to reflect the permeability and barrier function of intestinal mucosa (24), whereas plasma DAO levels are associated with intestinal mucosal epithelial cell injury and repair (25,26). We observed that Gln supplementation markedly decreased the levels of the aforementioned markers.…”