Therapeutic efficacy of decreased nitrite production by Bezafibrate in patients with primary biliary cirrhosis

Ehime University, Matuyama, Ehime, Japan
Journal of Gastroenterology (Impact Factor: 4.52). 03/2005; 40(2):157-63. DOI: 10.1007/s00535-004-1518-3
Source: PubMed


The therapeutic efficacy of bezafibrate, a hypolipidemic drug, has been shown in patients with primary biliary cirrhosis (PBC) in some pilot studies; however, little is known regarding the mechanism of action of bezafibrate in PBC. This study was conducted to evaluate the therapeutic efficacy, as well as to gain insight about the possible mechanism of action, of bezafibrate in PBC.
Sixteen patients with PBC were administered with bezafibrate (400 mg/day) either with (n = 10) or without ursodeoxycholic acid (UDCA; n = 6). The peripheral blood of these patients was collected before and at different times after therapy commencement, and antigen-presenting dendritic cells (DCs) were then cultured. The DCs were enriched and cultured with Staphylococcus aureus Cowan strain-1 for 48 h to evaluate their capacity to produce nitrite.
One month after the start of bezafibrate therapy, the serum levels of alkaline phosphatase (P = 0.0005), gamma-glutamyl transpeptidase (P = 0.0006), total cholesterol (P = 0.0072), and immunoglobulin M (P = 0.0281) were decreased significantly compared to those before patients started bezafibrate therapy. The levels of nitrite produced by DCs decreased in all patients with PBC within 1 month of commencement of bezafibrate therapy. Moreover, decreased nitrite production by DCs was also seen when nitrite production was evaluated 1 year after the start of bezafibrate therapy.
This study reconfirms the therapeutic efficacy of bezafibrate in patients with PBC, including those with UDCA-resistant PBC. Downregulation of nitrite production by DCs may have some relationship with the therapeutic efficacy of bezafibrate; however, further study will be needed to clarify whether or not the antiinflammatory activity of bezafibrate is mediated through nitrite production.

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    • "The therapeutic efficacy of bezafibrate, a hypolipidemic drug, has been shown in patients with PBC in some pilot studies. Down-regulation of nitrite production by dendritic cells may have some relationship with the therapeutic efficacy of bezafibrate for PBC (24). In our study, we found that bezafibrate could reduce BAFF-stimulated B-cell-induced Treg cell apoptosis and promote TGF-β and IL-10 expression in Tregs. "
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    ABSTRACT: Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs) play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF) is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment.
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