Scripps Research Institute, Department of Chemistry describes research in amyloidosis therapy

01-23-2007

A report, "Orally administered diflunisal stabilizes transthyretin against dissociation required for amyloidogenesis," is newly published data in Amyloid. According to a study from the United States, "Rate-limiting transthyretin (TTR) tetramer dissociation and monomer misfolding enable misassembly into numerous aggregate morphologies including amyloid, a process genetically linked to and thought to cause amyloid pathology. T119M TTR trans-suppressor subunit inclusion into tetramers otherwise composed of disease-associated subunits ameliorates human amyloidosis by increasing the tetramer dissociation barrier."

"Diflunisal binding to the 99% unoccupied L-thyroxine binding sites in TTR also increases the tetramer dissociation barrier; hence, we investigated the feasibility of using diflunisal for the treatment of human TTR amyloidosis using healthy volunteers. Diflunisal (125, 250 or 500 mg bid) was orally administered to groups of 10 subjects for 7 days to evaluate serum diflunisal concentration, diflunisal binding stoichiometry to TTR, and the extent of diflunisal imposed TTR kinetic stabilization against urea-and acid-mediated TTR denaturation in human serum. The rates of urea-mediated tetramer dissociation and acid-mediated aggregation as a function of diflunisal concentration were also evaluated in vitro, utilizing physiologically relevant concentrations identified by the above experiments. In the 250 mg bid group, 12 h after the 13th oral dose, the diflunisal serum concentration of 146 +/-39 microM was sufficient to afford a TTR binding stoichiometry exceeding 0.95 +/-0.13 (approximately 1.75 corrected)," wrote Y. Sekijima and colleagues, Scripps Research Institute, Department of Chemistry.

The researchers concluded: "Diflunisal binding to TTR at this dose slowed urea-mediated dissociation and acid-mediated TTR aggregation at least, threefold (p <0.05) in serum and in vitro, consistent with kinetic stabilization of TTR. Diflunisal-mediated kinetic stabilization of TTR should ameliorate TTR amyloidoses, provided that the nonsteroidal anti-inflammatory drug liabilities can be managed clinically."

Sekijima and colleagues published the results of their research in Amyloid (Orally administered diflunisal stabilizes transthyretin against dissociation required for amyloidogenesis. Amyloid, 2006;13(4):236-49).

For additional information, contact Y. Sekijima, The Scripps Research Institute, Dept. of Chemistry, La Jolla, CA 92037 U.S.

The publisher of the journal Amyloid can be contacted at: Parthenon Publishing Group, Richmond House, White Cross, South Road, Lancaster LA1 4XQ, England.

This article was prepared by Drug Law Week editors from staff and other reports. Copyright 2007, Drug Law Week via NewsRx.com.