james michael howard

SPONSORED LINKS BY GOOGLE

Acta Trop. 2007 Apr 24; [Epub ahead of print]
Dehydroepiandrosterone affects Trypanosoma cruzi tissue parasite
burdens in rats.
Santos CD, Toldo MP, Levy AM, Kawasse LM, Zucoloto S, do Prado JC.

Laboratório de Parasitologia, Departamento de Análises Clínicas,
Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de
Ribeirão Preto FCFRP-USP, Universidade de São Paulo, Avenida do Café s/n,
14040-903 Ribeirão Preto, SP, Brazil.

Dehydroepiandrosterone (DHEA), the predominant steroid hormone produced
by adrenal glands has significant effects on the immune system. DHEA
enhances immune responses against a wide range of viral, bacterial, and
parasitic pathogens. In the present study, we investigated the effects of
DHEA treatment during the acute phase of experimental Trypanosoma cruzi
infection. Male and female Wistar rats were infected with the Y strain of
T. cruzi and treated subcutaneously with 40mg/kg body weight/day of DHEA.
Myocardial parasitism and inflammation were always present in the heart
during the acute phase, in male and female infected animals, regardless of
DHEA treatment, but the numbers of amastigote nests in cardiomyocytes were
significantly lower in DHEA-treated rats. At the end of the acute phase,
the nests became rare or virtually absent in all experimental infections.
Histological analysis of the adrenal glands showed that treated males
displayed an absence of parasites. DHEA treatment also resulted in reduced
parasitisim of heart and adrenal glands, as indicated by fewer and smaller
amastigote burdens, and less inflammatory infiltrate and tissue
disorganization. DHEA treatment also resulted in thymic atrophy as measured
both by reduced weight and by a reduction in the number of cultured
activated thymocytes. In vitro analysis showed the number of activated
macrophages was higher in treated animals. Antibody levels were monitored
by complement-mediated lysis. Higher titers were observed in females when
compared to males; but DHEA treatment enhanced the percentage of lysis for
both sexes. These findings suggest that DHEA can play a role in the control
of parasite multiplication.