BOSTON, Oct 14, 2004 (United Press International via COMTEX) -- U.S. researchers have discovered an important biochemical pathway for muscle wasting associated with several diseases.

Researchers at Joslin Diabetes Center and other institutions used genetically altered mice to study the biochemical pathways underlying muscle wasting. They zeroed in on a protein called NF-kB, which is well known for its importance in immune cells, but was previously not known to be involved in muscle wasting.

The team created two different strains of transgenic mice, which were born normally but as they matured, their body weight dropped due to decreases in skeletal muscle mass. Their muscle fibers were also smaller than those of their non-genetically altered littermates.

When they treated the muscle-wasting mice with high doses of drugs called salicylates, the body weights of the mice increased. After six months of therapy, their body weight, muscle mass and muscle fiber size were nearly normal.

Muscle wasting is a hallmark of a number of diseases, including cancer, bacterial sepsis, AIDS, diabetes, and end-stage heart, kidney and obstructive pulmonary disease. Muscle wasting can cause generalized weakness and debilitation and in its extreme, when respiratory muscles are involved, asphyxia and even death.