Preventive and therapeutic potential of placental extract in contact hypersensitivity.

Immunoregulatory effects of placental extract and placenta-derived factors have been demonstrated in various conditions. Accordingly, placental extract has been used as certain types of medical intervention in Asian countries, whereas experimental evidence supporting its therapeutic effects and mechanisms has yet to be fully demonstrated. In this study, we investigate preventive and therapeutic effects of placental extract in contact hypersensitivity (CHS), a mouse model of allergic contact dermatitis. Administration of placental extract prior to the sensitization of allergic antigen (Ag) significantly inhibited the severity of CHS induced by Ag challenge. This effect was associated with reduced numbers of CD4(+) T cells in peripheral blood, decrease of tissue-infiltrating lymphocytes, and preferential production of Th2-type cytokines in Ag-challenged sites. In addition, CHS caused by repetitive challenges of allergic Ag was also prevented and treated by administration of placental extract. Finally, administration of cyclo-trans-4-L-hydroxyprolyl-L-serine, a dipeptide derived from placental extract, also alleviated CHS, suggesting its potential role in the effects of placental extract in CHS. Taken together, our findings demonstrated experimental evidence supporting immunoregulatory effects of placental extract in allergic skin diseases and elucidated its potential mechanisms.

Laennec protects murine from concanavalin A-induced liver injury through inhibition of inflammatory reactions and hepatocyte apoptosis.

The effect of Laennec, a hydrolyte of human placenta, on immune-mediated liver injury was investigated in vivo and in vitro in murine. Vena caudalis administration of concanavalin A (Con A) was employed to establish an in vivo liver-injury model, and in vitro hepatotoxicity was induced by 8 h interaction between Con A pre-treated hepatocytes and Con A-stimulated autologous splenic lymphocytes. Laennec was used for pre-treatment in the two models. Laennec decreased biochemical marker activity (alanine aminotransferase, ALT; lactate dehydrogenase, LDH) in serum and recovered the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), as well as the content of malondialdehyde (MDA) and nitric oxide (NO) in liver tissue. We also found that the DNA ladder induced by Con A in vivo was attenuated by Laennec. Furthermore, the leakage of aspartate aminotransferase (AST) and LDH in the supernatant of the co-culture system was decreased by addition of Laennec. Potential protective mechanisms were elucidated by DNA fragmentation assay and intercellular adhesion molecule-1 (ICAM-1) induction/inhibition experiments. Results showed that ICAM-1, which is related to the interaction between hepatocytes and lymphocytes, was inhibited by Laennec. These findings indicated that Laennec has potent activity against immune-mediated liver injury.