Pseudomonas aeruginosa biofilm is a potent inducer of phagocyte hyperinflammation

Objective Pseudomonas aeruginosa effectively facilitate resistance to phagocyte killing by biofilm formation. However,b the cross talk between biofilm components and phagocytes is still unclear. We hypothesize that a biofilm provides a concentrated extracellular source of LPS, DNA and exopolysaccharides (EPS), which polarize neighbouring phagocytes into an adverse hyperinflammatory state of activation. Methods We measured the release of a panel of mediators produced in vitro by murine neutrophils and macrophages exposed to various biofilm components of P. aeruginosa cultures. Results We found that conditioned media from a high biofilm-producing strain of P. aeruginosa, PAR5, accumulated high concentrations of extracellular bacterial LPS, DNA and EPS by 72 h. These conditioned media induced phagocytes to release a hyperinflammatory pattern of mediators, with enhanced levels of $TNF-\alpha$, IL-6, IL12p40, $PGE_{2}$ and NO. Moreover, the phagocytes also upregulated COX-2 and iNOS with no influence on the expression of arginase-1. Conclusions Phagocytes exposed to biofilm microenvironment, called by us biofilm-associated neutrophils/macrophages (BANs/BAMs), display secretory properties similar to that of N1/M1-type phagocytes. These results suggest that in vivo high concentrations of LPS and DNA, trapped in biofilm by EPS, might convert infiltrating phagocytes into cells responsible for tissue injury without direct contact with bacteria and phagocytosis

Pseudomonas aeruginosa biofilm is a potent inducer of phagocyte hyperinflammation

OBJECTIVE: Pseudomonas aeruginosa effectively facilitate resistance to phagocyte killing by biofilm formation. However, the cross talk between biofilm components and phagocytes is still unclear. We hypothesize that a biofilm provides a concentrated extracellular source of LPS, DNA and exopolysaccharides (EPS), which polarize neighbouring phagocytes into an adverse hyperinflammatory state of activation. METHODS: We measured the release of a panel of mediators produced in vitro by murine neutrophils and macrophages exposed to various biofilm components of P. aeruginosa cultures. RESULTS: We found that conditioned media from a high biofilm-producing strain of P. aeruginosa, PAR5, accumulated high concentrations of extracellular bacterial LPS, DNA and EPS by 72 h. These conditioned media induced phagocytes to release a hyperinflammatory pattern of mediators, with enhanced levels of TNF-α, IL-6, IL12p40, PGE2 and NO. Moreover, the phagocytes also upregulated COX-2 and iNOS with no influence on the expression of arginase-1. CONCLUSIONS: Phagocytes exposed to biofilm microenvironment, called by us biofilm-associated neutrophils/macrophages (BANs/BAMs), display secretory properties similar to that of N1/M1-type phagocytes. These results suggest that in vivo high concentrations of LPS and DNA, trapped in biofilm by EPS, might convert infiltrating phagocytes into cells responsible for tissue injury without direct contact with bacteria and phagocytosis

Influence of the supplementation of glutamic acid,histidine and arginine to the diet,on dietary intake,weight gain and chemical body mass composition in rats

Prześledzono wpływ kwasu glutaminowego, histydyny i argininy na spożycie diet, przyrosty i skład chemiczny masy ciała 30-dniowych samców szczurzych szczepu Wistar. Źródłem białka w dietach była kazeina. Do diet dodano jeden z badanych aminokwasów w ilości 5g/100g diety. Dodatek tych aminokwasów spowodował istotne obniżenie spożycia diet, przyrostu masy ciała i jego składników, tj. wody, białka, tłuszczu i popiołu. Dodatek histydyny do diety powodował obniżenie stosunku azotu do wody w ciele, co świadczyło o opóźnieniu chemicznego dojrzewania tkanek, równocześnie ze zmniejszeniem procentowej zawartości tłuszczu w ciele.100 male rats, aged 30 ± 1 days were investigated by means of 28 days study. The influence of the supplementation of glutaminie acid, histidine and arginine to the diet on dietary intake, weight gain and chemical composition was determinated. It was casein that was used as the source of protein. We investigated the application of 4 kinds of diet during each experiment and the composition of the diets was based on the Miller-Bend non-protein diet model. 100 male rats, aged 30 ± 1 days were investigated by means of 28 days study. The influence of the supplementation of glutaminie acid, histidine and arginine to the diet on dietary intake, weight gain and chemical composition was determinated. It was casein that was used as the source of protein. We investigated the application of 4 kinds of diet during each experiment and the composition of the diets was based on the Miller-Bend non-protein diet model