Some statins —drugs that lower blood cholesterol levels—have been linked to various adverse events. Now, an emerging study has found that the medications might be negatively affecting patients with Multiple Sclerosis (MS), reports Science Daily, especially in those patients taking high daily doses of statins.
MS is an autoimmune disease of the central nervous system (CNS) and involves the immune cells attacking the nerve fibers’ protective insulation, known as the myelin sheath, as well as myelin-producing cells of the CNS, called oligodendrocytes, explained Science Daily. These activities cause demyelination, which results in damage that hinders “the nerve cell’s ability to transmit signals throughout the nervous system,” Science Daily added.
Researchers looked at the effects of statins on myelin repair in mice and found that statins inhibit remyelination (myelin repair) in the central nervous system, said Science Daily. The study was conducted at the Montreal Neurological Institute (MNI), McGill University; the findings were published in The American Journal of Pathology. The study looked at how simvastatin—a statin in clinical trials—affected myelin in the brain and also looked at the remyelination process, said Science Daily.
The researchers discovered that “simvastatin has in fact, a slightly deleterious effect on myelin,” said Dr. Miron, quoted Science Daily. Dr. Veronique Miron is a post-doctoral fellow at the MNI and is a lead investigator in the study. Dr. Miron explained that during remyelination, myelin and oligodendrocyte production decreases with simvastatin, which means that simvastatin hampers CNS remyelination. This is of note because, in early MS, when an immune system attack on myelin occurs, the oligodendrocyte progenitor cells or stem cells in the CNS work to repair the damage, said Science Daily. If the myelin damage is not reversed, the degeneration continues and worsens.
Other statins have also been in the news for some time over various side effects. For instance, Baycol (generic: cerivastatin) was approved in the United States in 1997, but was pulled from the market in August 2001 because it was linked to Rhabdomyolysis, which caused 31 deaths in the United States. Rhabdomyolysis is a condition that causes muscle-cell breakdown (atrophy) and leads to muscle pain, weakness, tenderness, malaise, fever, dark urine, nausea, and vomiting and is also known to be life threatening. Rhabdomyolysis also injures the kidneys because of the toxic effects of the contents of muscle cells. Myoglobin is an iron-containing pigment found in the skeletal muscle. When the skeletal muscle is damaged, myoglobin is released into the bloodstream and is filtered out by the kidneys. Myoglobin may occlude the structures of the kidney, causing damage such as acute tubular necrosis or kidney failure. Myoglobin breaks down into potentially toxic compounds, which also cause kidney failure.
Crestor, another statin, has also been linked to kidney damage, kidney failure, and Rhabdomyolysis. On October 22, 2004, the consumer group Public Citizen said 29 patients who took AstraZeneca’s cholesterol drug Crestor developed kidney damage and also noted that the rate of reported kidney problems is approximately 75 times higher with Crestor than with all other drugs in the same class combined. The FDA approved Crestor in August 2003 following a delay over safety concerns.
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