In vitro immunomodulation of splenocytes from DO11.10 mice by the food colouring agent amaranth.

The chemical amaranth (AM) is permitted as a colouring agent in a variety of foods. Safety was established based on chronic rodent studies. AM and its metabolite naphthionic acid (NA) can be absorbed through the intestine, exposing circulating immune cells including splenocytes. An AM feeding study in rats demonstrated an increase in blood lymphocytes. Yet, in contrast, AM inhibited the delayed-type hypersensitivity reaction to antigen. DO11.10 mice express a T Cell Receptor specific for ovalbumin323-339 peptide (OVAp) presented by I-Ad MHCII. DO11.10 splenocytes were cultured to evaluate mechanisms by which AM and NA modulate immune cell function in vitro. Exposure to OVAp alone for 72 h induced cell proliferation, and combination with 2 or 20 µg/mL AM increased IFN-γ. Cytotoxicity was evident at higher concentrations of AM (200 and 2000 µg/mL) and NA (2000 µg/mL) in combination with OVAp, as both cell number and cytokine secretion decreased. At 200 µg/mL AM with OVAp, immunotoxicity gene expression was modified and OVAp-specific KJ1-26+ CD28+ cells became enriched. The equivalent dose of NA did not modify those parameters. Using an antigen-specific model in vitro, lower concentrations of AM potentiated pro-inflammatory cytokine production, and higher concentrations of AM and NA demonstrated cytotoxicity.

Albumin resuscitation increases cardiomyocyte contractility and decreases nitric oxide synthase II expression in rat endotoxemia.

OBJECTIVE: Hypotension and hypoperfusion during septic shock may contribute to tissue hypoxia and the intramyocardial inflammatory response that results in myocardial dysfunction. Therefore, we hypothesized that crystalloid or colloid resuscitation may alter myocardial dysfunction. DESIGN: Randomized, controlled, prospective animal study. SETTING: University animal laboratory. SUBJECTS: Sprague-Dawley rats (250-300 g, n = 6/group). INTERVENTIONS: Rats received an intraperitoneal injection of 10 mg/kg lipopolysaccharide or control. One hour later, rats were randomized to intravenous resuscitation and received either 30 mL/kg normal saline, 10 mL/kg 10% pentastarch, 10 mL/kg 5% rat albumin, or no volume. MEASUREMENTS AND MAIN RESULTS: We measured fractional shortening of cardiomyocytes isolated 5 hrs after lipopolysaccharide or control injection. In separate identical experiments, we measured myocardial interleukin-6, macrophage inhibitory protein-2, and nitric oxide synthase II protein and messenger RNA expression. Control fractional shortening of 24.1 +/- 2.2% was decreased by lipopolysaccharide to 18.8 +/- 1.2% (p <.001). Volume resuscitation after lipopolysaccharide significantly improved fractional shortening (p <.001). In particular, albumin resuscitation increased fractional shortening to 23.5 +/- 0.9%, which was more than either saline (fractional shortening 20.1 +/- 1.7%,p <.01) or pentastarch (fractional shortening 21.4 +/- 0.9%,p <.01). Myocardial macrophage inhibitory protein-2 protein and interleukin-6 and macrophage inhibitory protein-2 messenger RNA expression and neutrophil content were elevated following lipopolysaccharide (p <.05) but were not altered by volume resuscitation. Myocardial nitric oxide synthase II protein and messenger RNA expression increased following lipopolysaccharide (p <.01) and decreased with albumin resuscitation. CONCLUSIONS: We conclude that following lipopolysaccharide injection, volume resuscitation improves cardiomyocyte fractional shortening. Albumin resuscitation is particularly beneficial in preventing reduced cardiomyocyte contractility, and this benefit may be related to an albumin-induced reduction in nitric oxide synthase II protein and messenger RNA expression following endotoxin injection.