The use of glucocorticoid steroids for the treatment of various medical conditions is sometimes accompanied with extra caution due to their potential to cause muscle wasting. However, researchers found in one study that weekly dosing could make them more beneficial.
Glucocorticoid steroids, such as prednisone, are often employed in the treatment of autoimmune and chronic inflammatory disorders, among others. They are considered to be useful for treating muscle injury and dystrophy as a result of their positive effects on muscle repair and recovery.
However, long-term use or chronic systemic exposure to these substances is believed to promote muscle weakness and wasting. This speeds up muscle breakdown. The adverse effects are major reasons why patients who need them for treating these chronic medical conditions often quit using them.
But some researchers at Northwestern University found in a mice study published in the Journal of Clinical Investigation that taking a different approach to the use of glucocorticoid steroids may make them more beneficial. They observed that using the drugs on a weekly basis, instead of daily, facilitated muscle repair.
The scientists found that prednisone helped to improve annexin production. This is a class of proteins that support the healing of muscles.
In addition, weekly doses of the steroids helped to increase a molecule referred to as KLF15, which produces a positive effect on muscle performance. Daily doses, on the other hand, lowered the molecule, with this resulting in muscle wasting.
“We don’t have human data yet, but these findings strongly suggest some alternative way of giving a very commonly used drug in a manner that doesn’t harm, but in fact helps muscle,” lead researcher Dr. Elizabeth McNally said.
Improved repair and strength
Researchers in the Northwestern University study gave steroids to some healthy mice just before a muscle injury and also for two weeks following the injury.
Mice that received two weekly steroid doses had stronger muscles and performed better on a treadmill, than those that got a placebo. But the animals that received daily doses of steroids fared worse in terms of muscle strength and treadmill performance.
McNally and her team made use of high-resolution imaging to assess the ability of the muscle to self-repair and how steroids could help speed up the process.
They made a hole in muscle cells using laser and then observed in real-time as cells repair the hole naturally. After introducing steroids, they noticed that muscle healed more rapidly.
“We were like, ‘Wow!’ It accelerated the repair in muscle cells,” said McNally, the Elizabeth J. Ward Professor of Genetic Medicine at Feinberg School of Medicine, Northwestern University.
Mice who had their leg muscles damaged recovered faster from the injury after being given steroids.
Correcting muscular dystrophy
McNally wanted to have a better idea of how the steroid could help a patient avoid a wheelchair for longer.
The conditions the drug is used to treat include muscle inflammation (myositis) and Duchenne Muscular Dystrophy, one of a group of genetic disorders that lead to progressive loss of muscle mass and weakness. Yet, a side effect of it is muscle wasting.
McNally said an average boy suffering from Duchenne Muscular Dystrophy will need a wheelchair for movement by age 10. But steroids can enable such to walk independently for three more years.
Their study showed a safer approach to using these compounds without the side effects that often accompany them.
The scientists tested prednisone on muscular dystrophy in the mouse model. They found that weekly doses made mice with muscular dystrophy stronger and to perform better on a treadmill, compared to those that received a placebo. But mice that got daily doses showed muscle atrophy and wasting.
McNally revealed her interest in carrying out human studies on how steroids may be beneficial for certain forms of muscular dystrophy that these substances are currently not being used for.
- Once-weekly steroid dosing can promote muscle repair without atrophy (https://www.medicalxpress.com/news/2017-05-once-weekly-steroid-dosing-muscle-atrophy.html)