RESUMO

SCOPE: Perinatal maternal moderately high-fat diet (mHFD) is associated with obesity and fatty liver disease in offspring, and maternal fish oil (FO: n-3 PUFA source) supplementation may attenuate these disorders. This study evaluates the effects of FO given to pregnant rats fed a mHFD on the offspring's liver at weaning. METHODS AND RESULTS: Female Wistar rats receive an isoenergetic, control (CT: 10.9% from fat) or high-fat (HF: 28.7% from fat) diet before mating, and throughout pregnancy and lactation. FO supplementation (HFFO: 2.9% of FO in the HF diet) is given to one subgroup of HF dams during pregnancy. At weaning, male and female mHFD offspring display higher body mass, adiposity, and hepatic cellular damage, steatosis, and inflammation, accompanied by increased damaged mitochondria. FO does not protect pups from systemic metabolic alterations and partially mitigates hepatic histological damage induced by mHFD only in females. However, FO reduces mRNA expression of lipogenic genes, and mitochondrial damage, and modified mitochondrial morphology suggestive of early adaptations via mitochondrial dynamics. CONCLUSIONS: Gestational FO supplementation has limited beneficial effects on the damage caused by perinatal mHFD consumption in offspring's liver at weaning. However, FO imprinting effect on lipid metabolism and mitochondria may have beneficial long-term outcomes.

Assuntos

RESUMO

BACKGROUND: The Trypanosoma cruzi infection is associated with severe T cell unresponsiveness to antigens and mitogens characterized by decreased IL-2 synthesis. Trypanosoma cruzi mucin (Tc Muc) has been implicated in this phenomenom. These molecules contain a unique type of glycosylation consisting of several sialylated O-glycans linked to the protein backbone via N-acetylglucosamine residues. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we evaluated the ability of Tc Muc to modulate the activation of CD4(+) T cells. Our data show that cross-linking of CD3 on naïve CD4(+) T cells in the presence of Tc Muc resulted in the inhibition of both cytokine secretion and proliferation. We further show that the sialylated O-Linked Glycan residues from tc mucin potentiate the suppression of T cell response by inducing G1-phase cell cycle arrest associated with upregulation of mitogen inhibitor p27(kip1). These inhibitory effects cannot be reversed by the addition of exogenous IL-2, rendering CD4(+) T cells anergic when activated by TCR triggering. Additionally, in vivo administration of Tc Muc during T. cruzi infection enhanced parasitemia and aggravated heart damage. Analysis of recall responses during infection showed lower frequencies of IFN-γ producing CD4(+) T cells in the spleen of Tc Muc treated mice, compared to untreated controls. CONCLUSIONS/SIGNIFICANCE: Our results indicate that Tc Muc mediates inhibitory efects on CD4(+) T expansion and cytokine production, by blocking cell cycle progression in the G1 phase. We propose that the sialyl motif of Tc Muc is able to interact with sialic acid-binding Ig-like lectins (Siglecs) on CD4(+) T cells, which may allow the parasite to modulate the immune system.

Assuntos

RESUMO

A biocompatibilidade de uma membrana de pericárdio bovino foi avaliada em tecido subcutâneo de camundongos 3,7, 15, 30 e 60 dias após a implantação. Os componentes celulares da resposta inflamatória, a degradação da membranae as características do colágeno foram analisadas em cortes histológicos corados pela hematoxilina-eosina, tricrômico de Masson e Picro-Sírius, respectivamente. Para verificar seu potencial como carreador celular, osteoblastos humanos(hFOB1.19, ATCC) foram semeados sobre a membrana e mantidos em DMEM/F12 por 7 dias. Os resultados in vitro mostraram que os osteoblastos proliferaram em monocamada na superfície da membrana, mas sem penetrar em seu interior. A análise dos cortes histológicos demonstrou 3 dias após a implantação apenas a formação da rede de fibrina. Aos 7 dias, o material implantado estava circundado por células inflamatórias mononucleares, com pouca penetração celular no seu interior. Após 15 dias foi observado um intenso infiltrado inflamatório em contato e dentro do material,bem como sinais de degradação interna e externa. No período de 30 dias, o material, em processo bastante avançado de absorção, estava totalmente tomado por fibroblastos e macrófagos. Aos 60 dias pós-implantação, o material não foi maisdetectado em quaisquer dos animais e a tecido subcutâneo apresentava-se normal. Os cortes corados com Picro-Sírius e observados sob luz polarizada mostraram o remodelamento tecidual. Em conclusão, a membrana de pericárdio é bioabsorvívele biocompatível, porém, in vitro, não proporciona uma adequada matriz tridimensional para osteoblastos.

The biocompatibility of a pericardium membrane was evaluated in the subcutaneous tissue of mouse killed 3, 7, 15, 30 and 60 days post implantation. The cellular components of inflammatory infiltrate, the membrane degradation, and the collagen characteristic were analyzed in histological sections stained with hematoxilyn and eosin, Tricromic of Masson and Sirius Red, respectively. The potential features as a tissue engineering scaffold was tested in vitro using human osteoblasts (h.Fob 1.19, ATCC) seeded over the membrane and maintained for 7 days in DMEM/F12. We observed in vitro the monolayer proliferation of osteoblasts, but without penetrating in the membrane. The histological sections showed after 3 days of implantation only the presence of a fibrin net. At the 7-day period, mononuclear inflammatory cells were observed around the implant, but a few one were observed inside the membrane. After 15 days the inflammatory infiltrate was more intense than in the previous period and the cells were inside and in close contact to the material showing evident signs of internal and external degradation. The implant degradation was intense after 30 days and theresidual material was fulfilled of fibroblasts and macrophages. No signs of membrane were observed after 60 days in any animals and the subcutaneous tissue presented normal aspect. Sirius Red staining at polarized light had evidenced the tissue remodeling throughout the experimental periods. In conclusion, the pericardium membrane is bioabsorbable and biocompatible, but, in vitro, do not fulfill the requirements as a tridimensional scaffold to osteoblast.

Assuntos