Role of nitric oxide on human schistosomiasis mansoni: upregulation of in vitro granuloma formation by N omega-nitro-L-arginine methyl ester.
Over the past decade, nitric oxide has been intensely studied due to its relevance as a widespread intra- and intercellular messenger and as a cytotoxin released during several physiopathological events, including immunological reactions and inflammation. In the present paper, we investigate the effect of inhibition of NO synthesis, using an analogue of L-arginine, N omega-nitro-L-arginine methyl ester (L-NAME), on in vitro granulomatous formation of human peripheral blood mononuclear cells (PBMC) from Schistosoma mansoni-infected individuals. The results demonstrated that human PBMC are capable of in vitro NO production and that inhibition of its production through the addition of L-NAME is responsible for exacerbating granulomatous reaction. This L-NAME-induced granuloma enhancement (ranging from 30 to 65%) was measured using the granuloma index. Furthermore, we observed a general time-dependent increase in NO production during the period of cell culture (21 days) and an inverse relationship between nitrite detection and granuloma reactivity. Collectively, our results point to a possible regulatory role of NO on the development of granulomatous inflammation.
Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.
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Silva-Teixeira
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D000947:Antigens, Helminth / Q000276:immunology; D002478:Cells, Cultured; D006099:Granuloma / Q000209:etiology* / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000139:chemically induced* / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009573:Nitrites / Q000032:analysis; D012555:Schistosomiasis mansoni / Q000276:immunology* / Q000378:metabolism; D013997:Time Factors
D000947:Antigens, Helminth; D009573:Nitrites; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester