Regenerative Strategies

A confocal microscopy image of human cardiac tissue bioengineered from pluripotent stem cells in the laboratory

This confocal microscopy image shows human cardiac tissue bioengineered from pluripotent stem cells in the laboratory. Scientists hope to determine if bioengineered cells from the patient's own body can be used to treat and strengthen the heart.

Today, standard treatment for people with hypoplastic left heart syndrome (HLHS) includes a three-stage surgery that enables the right ventricle to pump blood to the entire body.

Though effective, these surgeries are palliative and do not eliminate the person's risk of needing a heart transplant later. And because the right ventricle was never meant to support the entire body, the strain imposed can lead to declines in pumping ability over time.

Regenerative medicine strategies for HLHS have the potential to provide an alternative to heart transplantation. Using stem cells of different types and from various sources — including cells from the patient's own body — regenerative therapies for HLHS could replace, rejuvenate or regenerate defective tissues, leaving new, healthy tissues in their place.

Such approaches could restore the pumping ability of the right ventricle once it begins to decline or perhaps prevent the decline altogether, eliminating the need for a future heart transplant.

Long-term objective

  • Discover and make clinically available the safest and most effective regenerative therapies for HLHS

Investigative strategy

To create new and innovative regenerative therapies for HLHS, which includes determining from where and whom the cells can originate and when best to deliver them to patients, ongoing areas of focus for the regenerative strategies team include:

  • Tissue and biomarker profiling. After gathering surgically discarded tissues from children with HLHS — and skin biopsies from their unaffected parents — researchers are creating reprogrammed, pluripotent cell lines capable of differentiating into patient-specific cardiac tissues. Researchers are then searching, at the molecular level, for differences between bioengineered cardiac tissue from children with HLHS and their unaffected parents.
  • Development of a preclinical model. Before promising stem cell-based regenerative therapies for HLHS can be offered to people in clinical trials, their efficacy must be evaluated in preclinical models. Investigators are working to create a preclinical model of HLHS in which the right ventricle is overworked — just like in people with HLHS — so they can assess the effectiveness of emerging regenerative methodologies in repairing damaged cardiac tissue.
  • Umbilical cord blood. As blood from the umbilical cord contains stem cells, researchers are in the early stages of studying whether people with HLHS could benefit from direct myocardial injection of such cells during planned HLHS-related surgical procedures.

To learn more about regenerative medicine, watch Timothy J. Nelson, M.D., Ph.D., director of the Todd and Karen Wanek Family Program for HLHS, explain the regenerative medicine consult service at Mayo Clinic and how induced pluripotent stem cells can repair hearts.


If you have questions about research within the Todd and Karen Wanek Family Program for Hypoplastic Left Heart Syndrome or would like to learn more about research participation, please email us at