Weizmann Institute researchers have developed an effective treatment, administered through the nose, for a myasthenia gravis-like disease in rats, according to a report in the July 6 issue of the Proceedings of the National Academy of Sciences (PNAS).
The new approach used in the study may serve as a basis for treating myasthenia gravis in humans. "More studies will be necessary before applying our approach in clinical trials, but we have good reason to believe that an effective treatment for human patients can now be developed," said research team leader Prof. Sara Fuchs of the Institute's Immunology Department.
The team includes graduate students Dora Barchan and Sin-Hyeog Im, and Prof. Miriam Souroujon of The Open University in Tel Aviv.
Myasthenia gravis is an autoimmune disease in which the body's immune system mistakenly attacks the receptors in muscles that pick up acetylcholine, a chemical messenger that transmits signals from nerves to muscles. As these acetylcholine receptors are blocked by antibodies and progressively destroyed, the nerve-muscle communication is disrupted and the patient develops weakness in the muscles of the face, throat and limbs. In severe cases, paralysis of respiratory muscles can be life-threatening.
Currently, many patients with myasthenia gravis are given corticosteroid drugs that suppress the immune system, but these drugs may have undesirable side effects. An ideal treatment would suppress only the immune mechanism that goes awry in myasthenia gravis, without affecting the rest of the immune system.
For more than 20 years, Prof. Fuchs has worked with the animal model for myasthenia gravis, attempting to develop a treatment that would be specific for this disease.
In the study reported in PNAS, Fuchs's team genetically engineered a fragment of
the human acetylcholine receptor -- the part of the receptor molecule that
protrudes above the surface of muscle cells and reacts with various antibodies
Contact: Jeffrey J. Sussman
American Committee for the Weizmann Institute of Science