Muscular Dystrophy > Muscular Dystrophy Articles > Treatment of Muscular Dystrophy

Treatment of Muscular Dystrophy



At the moment, there is no cure for any of the 9 types of muscular dystrophy. Conventional methods of coping with the disease include exercise, drugs that slow down or eliminate muscle wasting, anabolic steroids and supplementation. These methods are aimed to slow down the progression of the disease, or reduce its symptoms, and usually they are effective in prolonging the lifespan of affected individuals

Researchers are already studying gene therapies to treat muscular dystrophies, but the results of this research - if any - will be available no sooner than several years from now

Researchers are also investigating the potential of certain muscle building medicines to slow down or reverse the progression of muscular dystrophy. Other trials are looking into the effects of the dietary supplements creatine and glutamine on muscle energy production and storage.

Symptoms can often be reduced through exercise, physical therapy, respiratory care, surgery and rehabilitative devices. This can be particularly helpful in minimizing painful positioning of the joints and in preventing or reducing abnormal curvatures of the spine. Walking aids such as canes or wheelchairs can help sufferers maintain mobility and independence. Surgery can help reduce or eliminate muscle shortening (which would otherwise cause a marked reduction in the range of motion). Medicines such as hormones can also be very helpful in reducing muscle wasting. In some forms of MD that affect respiratory muscles (such as Limb-Girdle Muscular Dystrophy) respiratory care and breathing exercises are often recommended. In Emery-Dreifuss and myotonic muscular dystrophy, a pacemaker is usually recommended to avoid sudden death due to heart complications

In Duchenne muscular dystrophy, corticosteroid hormones may slow muscle wasting. In myotonic muscular dystrophy, phenytoin, procainamide or quinine can treat delayed muscle relaxation. Medications can also be prescribed for some muscular dystrophy-related heart problems.

Physical therapy

As the illness progresses and muscles lose their strength, contractures can develop in joints. If tendons shorten, they can restrict the flexibility and mobility of joints, reducing the range of motion. Contractures are uncomfortable and may affect the joints of your feet, knees, hips, hands and elbows. One goal of physical therapy is to provide regular range-of-motion exercises to keep your joints as flexible as possible, delaying the progression of contractures, and reducing or delaying curvatures of your spine. Using hot baths (hydrotherapy) also can help maintain range of motion in joints.

Assistive devices

Braces are often used to support weakened muscles of your hands and lower legs and help keep muscles and tendons stretched and flexible, slowing the progression of contractures. Wheelchairs, canes and walkers are also used to help patients keep their independence and walking capabilities. If respiratory muscles become weak, using a ventilator may become necessary.

Medications

Drugs may be useful to treat some forms of muscular dystrophy:

  • Myotonic Dystrophy: The medications mexiletine (Mexitil), phenytoin (Dilantin, Phenytek), carbamazepine (Tegretol, Carbatrol), quinine and procainamide (Procanbid, Pronestyl) are used to treat or reduce myotonia (delayed muscle relaxation)
  • Duchenne Muscular Dystrophy: The anti-inflammatory corticosteroid medication prednisone helps improve muscle strength and delay the progression of the disease

Surgery

Tendon release surgeries are usually performed to relieve sufferers from painful joint positions. This kind of surgery may be performed to relieve tendons of your hip and knee and on the Achilles tendon at the back of your foot. Surgery may also be needed to correct curvature of the spine (scoliosis).

Nutritional Supplements and Steroids

Prednisone

Prednisone is a catabolic steroid that slows down muscle wasting and degeneration. It is the most widely used drug in the treatment for Duchenne Muscular Dystrophy. The effects of prednisone are increased strength and functionality in muscle cells. The ability to walk may be prolonged for some years.

This is not an anabolic steroid, but catabolic: this means that it acts by breaking down tissue, not building it. This apparent paradox is still not precisely explained, but many researchers think it's due to the anti-inflammatory and immunosuppressant effects of prednisone.

Prednisone works like hydrocortisone, by breaking down tissue to release glucose and mobilize energy in response to danger or stress: it also helps fighting inflammation by suppressing the immune system. Some researchers also believe that prednisone may stimulate muscle protein production.

Because of this glucose and energy release effect, catabolic steroids are also known as "glucocorticoids" or "corticosteroids" (since they are made and released from the cortex (outer portion) of the adrenal gland). Although prednisone works well, when affected individuals stop taking it the effects are rapidly lost, no matter how long they had been on it.

This drug also has several strong side effects, including:

  • Fluid retention (leading to weight gain and high blood pressure)
  • Cataracts
  • May slow growth in height
  • Difficulty concentrating, sleeping and controlling one's emotions
  • Learning impairment (difficulty reading and thinking)
  • Depression
  • Prolonged use of immunosuppressants may lead to a reduced ability of the body to ward off infections

The usage of prednisone must be monitored carefully to ensure that the benefits are outweighing the side effects. Dosage is still a debate among doctors, but it is generally administered in alternating periods on and off and in daily doses of 0.75 mg/kg body mass/day

Prednisone may also be administered with dietary supplements such as calcium

Deflazacort
This is a catabolic steroid like prednisone. However, it is not marketed in the U.S. (it can be found in Canada and Mexico). Some people prefer deflazacort over prednisone because it preserves its benefits with milder side effects. However, it is generally difficult to obtain for U.S. residents - although in the past it was possible to obtain deflazacort (with a prescription only) through Victoria Pharmacy in Switzerland.
Albuterol
Albuterol is another immunosuppressant, commonly used in inhalers for asthmatics. It is believed to work like prednisone - by stimulating muscle growth and suppressing the immune cells that remove debris and muscle cells. This also means that it still interferes with the body's natural immune defenses, so its side effects (while relatively few) may be a reduced ability to fight infections
Creatine

This nutritional supplement is generally used by athletes who want to increase their performance. Creatine helps muscles contract more forcefully, thus improving the natural functionality of muscle cells. The creatine kinase or CK enzyme (which is released from damaged muscle cells in DMD) adds chemical groups called 'phosphates' to creatine. Creatine stores these phosphate groups and donates them to contractile muscle filaments, which need them to contract.

Creatine is found naturally in muscles, and can be obtained by eating meat or fish, but is also commercialized as a powder to be added to water. Studies have shown that a level of 5g/day is sufficient to improve muscle strength in DMD patients, while still being low enough to prevent kidney damage (a common side effect of creatine overload).

Anabolic Steroids

These hormones are often used by body builders to increase the body's natural ability to build muscle mass. In DMD patients, they act in the same way by helping the body build muscle faster, thus slowing down muscle wasting.

A pilot study of a synthetic anabolic steroid - oxandrolone - showed some promise in preserving muscle strength. Anabolic steroids, however, have many side effects (including sterility, liver and kidney damage, stunting of growth, mood swings, and an increased probability of incidence of some cancers). However, the levels of anabolic steroids used by affected individuals are much lower than those used by body builders, and thus have less severe side effects. At these low dosages, however, the effects on muscle regeneration appear minimal

Calcium Blockers

Research has shown calcium blockers to slow down the debilitating effects of Duchenne Muscular Dystrophy. In individuals with DMD, calcium leaks out of cells, causing damage to nearby tissue. Calcium blockers work by blocking the channels that leak out calcium.

The effectiveness of these drugs is questionable, considering that prednisone may cause osteoporosis (which requires oral calcium supplements) as a side effect

Gentamycin

This antibiotic has been featured in recent news, and is one of the most promising drugs for DMD. Unfortunately, it is only useful for about 10% of DMD cases - those caused by "stop codons" that prevent the decoding of the full dystrophin gene.

Research on mice has proven that when gentamycin is administered, the stop codons are ignored, so that the full gene can be translated into a functional dystrophin protein. A preliminary trial on men is currently being performed, and there are high hopes that the drug will work as well as it did on mice

Experimental Medications and Drugs

  • MY0-029

    MYO-029 is an experimental myostatin inhibiting drug developed by Wyeth Pharmaceuticals for the treatment of muscular dystrophy. Myostatin is a protein that inhibits the growth of muscle tissue, MYO-029 is a recombinant human antibody designed to bind and inhibit the activity of myostatin. A 2005/2006 trial was completed by Wyeth in Collegeville, PA. As of April 2007, the results of the study have not yet been made public, but it is one of the few known drugs in development for the treatment for muscular dystrophy.

  • PTC124

    This treatment has been proven to restore normal muscular function in mice affected by Duchenne Muscular Dystrophy, and may have the same effect on humans. In some patients, the disease is caused by a mutation that prevents the full construction of dystrophin. The new medicine, PTC124, prevents the body from terminating prematurely the full synthesis of dystrophin. PTC124 is already in clinical trials, although it will be several years before - and if - it is commercially available.


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