Practitioner's Post: Stem Cell Research for the HLHS Patient


If you've been following us on Facebook or Twitter, you've likely seen our posts and tweets about Dr. Timothy Nelson and the HLHS Research Program at the Mayo Clinic in Rochester, MN. The information Dr. Nelson and his researchers shared with Sisters by Heart is extremely fascinating and provides great hope (and a serious sense of urgency) for all of us affected by Hypoplastic Left Heart Syndrome. Thank you Dr. Nelson and the program's research coordinator, Julia, for sharing the latest developments in regenerative medicine for the HLHS patient.

I’m Timothy Nelson, MD, PhD, program director of the Todd and Karen Wanek Family Program for Hypoplastic Left Heart Syndrome at Mayo Clinic. The goal of our research program is to develop innovative clinical trials that offer the latest advances in cell-based therapy that could be used to treat people with HLHS.

Dr. Timothy Nelson in the lab

Upon completing the three stages of surgery, HLHS is ultimately a disease of the right ventricle that becomes too weak to be able to sustain normal cardiac function. Fortunately, surgical procedures over the last two decades have lead to dramatic improvement in the care of children with HLHS, but many questions remain unanswered.

Through our research, we hope to better understand the causes of HLHS, to develop a system for predicting right ventricle performance, and to determine whether or not the patient’s own stem cells could potentially be an effective treatment. Understanding whether stem cells are dysfunctional in patients with HLHS or whether they are normal will be very important to help determine whether the use of stem cells or regenerative medicine could be an appropriate therapeutic strategy. Who is the right person for regenerative therapies? What are the right types of stem cells? When is the right time for this potential therapy? To answer these questions, we are focusing on research studies that involve families affected by HLHS.

Our program is focused on the next generation of therapies that could be used to improve the function and long-term performance of the right ventricle – one of the potential therapies being regenerative medicine through the use of stem cells. Regenerative medicine is the process of regenerating human tissues with new building blocks to heal or replace damaged or diseased tissue. This would be similar to planting a seed in order to grow a flower. Stem cell therapies aim to transplant “stem cells” into damaged hearts with the goal of growing new heart muscle.

Bioengineered stem cells start with the collection of tissue, such as discarded skin from a surgical procedure, and are then converted into stem cells that can acquire a new ability to grow into heart muscle. These stem cells – and ultimately the bioengineered heart muscle derived from these cells – originate from the patient’s own body. These cells can then be studied in the laboratory to further understand the molecular causes of HLHS, and hopefully provide a powerful tool to better customize innovative solutions for people with HLHS.

To see video regarding the bioengineering of stem cells, watch this fascinating video; the video depicts how Dr. Nelson is creating bioengineered tissue for HLHS research.

Dr. Nelson's team shared with us the video clip of the beating cardiac tissue he's created in the lab.

Regenerative medicine strategies and stem cell-based therapeutics have been applied to heart disease in adult patients over the last 8 years. This experience allows us to consider the possibility of applying similar technology to patients with HLHS and other congenital heart disease. Although this is not yet available, the promising vision of this regenerative approach becoming a reality requires significant scientific and preclinical research studies to be the focus of today. We are fully dependent on the participation of families affected by HLHS in order to generate the data that is required to make the new discoveries and innovations for the clinical practice of tomorrow.

Although we don't yet know that stem cells will be used in the care of patients with HLHS, this type of research will be paramount for the scientific community to be able to make an informed decision as to the safety and efficacy of such hopeful therapeutic strategies. Ultimately, we hope our research will result in the ability to delay, or prevent, the need for heart transplants in people with this congenital heart condition. More information about the ongoing research for HLHS can be found at:

If you have specific questions regarding Dr. Nelson and his team's research, feel free to contact them at: