In a new study led by Dr. Subha Raman of The Ohio State University Wexner Medical Center, researchers were able to dramatically slow the rate of heart damage in patients with Duchenne muscular dystrophy by using a combination of well-established drugs. See the results of their study here.
Sadly, we are all aware that there is inherent, progressive heart damage with Duchenne muscular dystrophy. If we look at MDX mice, we see that initially the heart loses the ability to respond to stress or adrenaline. If we look directly at heart tissue from younger mice, and noninvasively examine the heart using cardiac MRIs in younger boys, we find evidence of heart muscle damage at a very early age. This damage forces the heart to “remodel,” or compensate for this damage, by reshaping and restructuring. This reshaping and restructuring leads to more heart muscle damage and results in the development of fibrosis. Ultimately, the function of the heart, as evaluated by the ejection fraction and shortening fraction measurements, decreases. However, we now know damage to heart muscle has been occurring for many years before these function measurements are noticeably decreased.
Aldosterone is a mineralocorticoid, produced by the adrenal grand (which lies on the top of the kidney) that promotes cardiac remodeling and, thus, contributes to the development of cardiac fibrosis. Drugs called aldosterone antagonists interfere with the uptake of aldosterone and, therefore, interfere with aldosterone’s normal activities. In a prior study in mice, Dr. Subha Raman, Dr. Jill Rafael-Fortney and other researchers at Ohio State University showed that the combination of an aldosterone antagonist and an ACE inhibitor greatly reduced the occurrence of cardiac fibrosis and maintained heart muscle function, particularly if started earlier vs. later.
These findings led to Dr. Raman, Dr. Cripe and other colleagues at OSU, Nationwide Children’s Hospital, Cincinnati Children’s Hospital and University of California Los Angeles to design and implement a clinical trial to test this combination of available heart medicines. The primary outcome measurement was a precise cardiac MRI-based measure of heart function called strain, which Dr. Kan Hor and others have shown to be abnormal in boys with Duchenne even when the ejection fraction is normal.
The study involved 42 boys who had evidence of early cardiac muscle damage by cardiac MRI, but whose ejection fraction was still ok. All were taking either an ACE inhibitor (ie, lisinopril) or an ARB (losartan) at the start and throughout the duration of the study, and most were also on a corticosteroid. Half of the boys were given eplerenone and the other half were given placebo, both in identical-looking tablets to keep both participants and study personnel blinded as to who was getting which medicine. The study medicine was taken once daily in addition to their other medications for 12 months.
Less heart muscle damage was seen at 6 months, and less decline in heart function was seen at 12 months when adding eplerenone to background ACE inhibitor or ARB therapy compared to adding placebo. The research team believes that by benefiting heart function at a very early stage, longer-term complications of cardiomyopathy such as heart failure can be greatly reduced. While continued research is needed to develop even better treatments for tomorrow, the availability of these medicines offers boys with Duchenne something beneficial for their hearts today.
Learn More about the Results of This Study
Thank you for supporting PPMD's cardiac initiative & helping us fund this promising research!