MS may not be autoimmune disease

Multiple sclerosis, long viewed as primarily an autoimmune disease, is not actually a disease of the immune system, a U.S. researcher says. Dr. Angelique of the John Jay College of Criminal Justice in New York suggests instead that MS is caused by faulty lipid metabolism -- in many ways more similar to coronary atherosclerosis -- hardening of the arteries -- than to other autoimmune diseases. Considering MS as a metabolic disorder helps to explain many puzzling aspects of the disease, particularly why it strikes women more than men and why cases are on the rise worldwide, Corthals said. Multiple sclerosis is mainly characterized by inflammation followed by scarring of tissue called myelin, which insulates nerve tissue in the brain and spinal cord. Over time, this scarring can lead to profound neurological damage, but medical researchers have theorized that a runaway immune system is at fault, but no one has been able to fully explain what triggers the onset of the disease. Corthals said the primary cause of MS can be traced to transcription factors in cell nuclei that control the uptake, breakdown, and release of lipids -- fats and similar compounds -- throughout the body. Disruption of these proteins, known as peroxisome proliferator-activated receptors, causes a toxic byproduct of "bad" low-density lipoprotein cholesterol to form plaque on the affected tissue. The accumulation of plaque in turn triggers an immune response, which ultimately leads to scarring. Corthals' framework explains why MS is more prevalent in women. "Men and women metabolize fats differently," Corthals said. "In men, problems are more likely to occur in vascular tissue, which is why atherosclerosis is more prevalent in men. But women metabolize fat differently in relation to their reproductive role." The findings are published in The Quarterly Review of Biology.