In a breakthrough clinical trial on humans, researchers used gene therapy to encourage the heart to repair itself after cardiac damage.
Mounting evidence has pointed towards the heart having a regenerative potential but its capacity for regeneration is insufficient to replace the massive loss of cardiomyocytes following ischaemic damage.
In this trial, published in Circulation Research, researchers made use of a naturally occurring factor called SDF-1 (stromal cell-derived factor-1) that is normally produced by the body’s cells to guide the activation and recruitment of stem cells. Following a heart attack, SDF-1, an inducible chemokine also known as CXCL12, is expressed to guide the stem cells towards replacing the cardiomyocytes. However, this SDF-1 expression is transient and only lasts for about a week – an insufficient length of time for the heart to be restored back to its original functionality.
The researchers capitalised on the regenerative power of SDF-1 by introducing plasmid DNA to induce expression of SDF-1 into the hearts of 17 patients with ischaemic cardiomyopathy. For each patient, one of three doses of the SDF-1 gene were used (5mg, 15mg or 30mg). The patients were monitored for up to a year with assessment of several outcomes. The researchers found:
- Patients improved their average distance by 40 meters during a six-minute walking test.
- Patients reported improved quality of life.
- The heart’s pumping ability improved, particularly for those receiving the two highest doses of SDF-1 compared to the lowest dose.
- No apparent side effects occurred with treatment.
This clinical trial shows that enhancing the recruitment of progenitor cells by overexpression of SDF-1 via gene therapy is a feasible strategy in patients with ischemic cardiomyopathy. Marc S. Penn, M.D., Ph.D., Director of Research at Summa Cardiovascular Institute in Akron, Ohio said in a press release: “Our study also shows gene therapy has the potential to help people heal their own hearts.”
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If you’d like to hear more about innovations and strategy in regenerative medicine, you might be interested in attending the World Stem Cells & Regenerative Medicine Congress 18-21 March 2013, at Resorts World Sentosa, Singapore. Click here to download the brochure.
