title: Growth hormones therapy in immune response against Trypanosoma cruzi.
abstract: Growth hormone (GH) is an important hypophyseal hormone that is primarily involved in body growth and metabolism. In mammals, control of Trypanosoma cruzi parasitism during the acute phase of infection is considered to be critically dependent on direct macrophage activation by cytokines. To explore the possibility that GH might be effective in the treatment of Chagas' disease, we investigated its effects on the course of T. cruzi infection in rats, focusing our analyses on its influences on parasitemia, NO, TNF-alpha and IFN-gamma concentration and on histopathological alterations and parasite burden in heart tissue. T. cruzi-infected male Wistar rats were intraperitoneally treated with 5 ng/10 g body weight/day of GH. Animals treated with GH showed a significant reduction in the number of blood trypomastigotes during the acute phase of infection compared with untreated animals (P<0.05). For all experimental days (7, 14 and 21 post infection) of the acute phase, infected and GH treated animals reached higher concentrations of TNF-alpha, IFN-gamma and nitric oxide as compared to untreated and infected counterparts (P<0.05) Histopathological observations of heart tissue revealed that GH administration also resulted in fewer and smaller amastigote burdens, and less inflammatory infiltrate and tissue disorganization, indicating a reduced parasitism of this tissue. These results show that GH can be considered as an immunomodulator substance for controlling parasite replication and combined with the current drug used may represent in the future a new therapeutic tool to reduce the harmful effects of Chagas' disease.
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto FCFRP-USP, Universidade de São Paulo, Brazil.
authors.forename: Eduardo Osório
authors.initials: EO
authors.lastname: Frare
authors.forename: Fabricia Helena
authors.initials: FH
authors.lastname: Santello
authors.forename: Leony Cristina
authors.initials: LC
authors.lastname: Caetano
authors.forename: Jerri C
authors.initials: JC
authors.lastname: Caldeira
authors.forename: Míriam Paula Alonso
authors.initials: MP
authors.lastname: Toldo
authors.forename: José Clóvis do
authors.initials: JC
authors.lastname: Prado
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000469:parasitology; D013006:Growth Hormone / Q000627:therapeutic use*; D006321:Heart / Q000469:parasitology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D018512:Parasitemia / Q000188:drug therapy; D051381:Rats; D017208:Rats, Wistar; D014349:Trypanosoma cruzi / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D013006:Growth Hormone