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Study Provides Clues to Muscle Weakness in Alcoholism, Mitochondrial Disease

Posted in Addiction News

 Study Provides Clues to Muscle Weakness in Alcoholism, Mitochondrial DiseaseMuscle weakness is a known symptom occurring among those with a long-term dependence on alcohol. The same symptom is found among patients diagnosed with mitochondrial disease.

The link between alcohol addiction and mitochondrial disease was defined by a study conducted recently and featured in an article in Science Daily. The study found that mitochondria are unable to self-repair, whether the damage is the result of mitochondrial disease or alcoholism. The findings were originally published in a recent issue of The Journal of Cell Biology. 

The findings provide clinicians with a new way to determine whether mitochondrial disease is present in a patient. It may also provide the information necessary to develop a pharmacological solution to mitochondrial breakdown.

Mitochondria are tiny energy producers that feed cells, whether they are muscle cells or cells in the brain. Mitochondria are self-repairing, fusing with other mitochondria to discard broken pieces and join those that are well-functioning. When mitochondria fuse, the damaged components are set aside to be recycled.

The fusion process is observable in many cell types, but researchers have previously been unable to observe mitochondria in skeletal muscle tissue. The fibers of muscle cells are so dense that, despite a high level of need for mitochondrial repair muscles, the process was assumed to be impossible in this type of cell.

However, another recent study documented the fusion that occurs between mitochondria in muscle cells. Veronica Eisner, Ph.D., a postdoctoral fellow at Thomas Jefferson University, was able to tag mitochondria in skeletal muscle tissue of rats with two different colors. The researchers were able to observe the process of the mitochondria and observe when there was damage and a subsequent self-repair. The result was evidence of the mitochondria fusing, just as they do in other types of cells.

The study provided new information, proving that mitochondrial self-repair may be a problem in disorders that have as an identifying characteristic a marked level of muscle weakness.

In the current study, Dr. Gyorgy Hajnoczky, M.D., Ph.D., director of Jefferson’s MitoCare Center and professor of Pathology, Anatomy & Cell biology, went on to investigate more fully the fusion process of mitochondria in skeletal muscle tissue cells. Dr. Hajnoczky was able to identify the most important of the fusion proteins, known as Mfn1.

After identifying Mfn1, the researchers tested to see whether mitochondrial fusion was the problem in other disorders exhibiting muscle weakness, like alcoholism. The researchers showed that in rats on a regular dose of alcohol, there was a 50 percent reduction in Mfn1 abundance. The decrease of Mfn1 was shown to correlate with a significant decrease in mitochondrial fusion.

The restoration of Mfn1 also led to the restoration of mitochondrial fusion. In addition, the link between decreased Mfn1 and decreased mitochondrial fusion was connected to increased levels of muscle fatigue.

Hajnoczky told Science Daily that the effect of alcohol on a specific gene involved in mitochondrial fusion suggests that additional environmental factors could significantly impact mitochondrial fusion and self-repair.

In addition, the research suggests that mitochondrial fusion may be linked with more than just the small number of mitochondrial diseases. It may be that the process is impacted by various environmental influences and may be, in turn, impacting other disorders.

The identification of the specific protein important in mitochondrial fusion may lead to the development of a medication targeted to increasing muscle strength through the bolstering of mitochondrial processes.

Such a medication could be an important step for helping both those with mitochondrial disease and an alcohol addiction increase muscle strength and gain the ability to treat other aspects of the disorder.

The information from the study may also be helpful in identifying a root cause of other disorders that may note muscle weakness among symptoms. Environmental influences may play a significant role in affecting mitochondrial self-repair.