STANFORD UNIVERSITY — Yasuhiro Shudo and his team at Stanford University published a study in Stem Cell Reports on July 2, 2026, describing a method to regenerate microvessels in the heart using stem cell-derived vascular organoids. The study demonstrated improved heart function and promoted microvessel regeneration in pigs with ischemic heart disease.

The research team created vascular organoids from endothelial progenitor cells isolated from human blood and mesenchymal stem cell-derived smooth muscle cells from human bone marrow. These vascular organoids are small cell aggregates capable of forming new blood vessels. The team then placed patches of these organoids onto the outer heart surface of pigs diagnosed with ischemic heart disease (IHD).

The pigs were monitored for four weeks following the application of the organoid patches. Heart function in the animals that received the organoid patches showed improvement when compared to untreated animals. The progression of IHD toward heart failure was also mitigated in the pigs receiving organoid patches.

The organoid patches remained viable for several weeks within the pig hearts. Individual cells from the surface patches were observed in deeper layers of the pig hearts, suggesting cellular migration into the heart muscle. These patches indirectly stimulated the pig hearts to produce new microvessels.

The effects of the organoid patches resulted in measurably higher microvessel density and maturity in the transplanted hearts. The patches may have contributed to preserving the viability of heart muscle cells by releasing proteins that support cell survival. The study utilized a large animal model, pigs, because of their similar heart size and physiology to the human heart.

Why It Matters

Ischemic heart disease, also known as coronary artery disease, stands as a leading cause of death and morbidity in Western countries. This condition develops when the heart's blood vessels become clogged, reducing oxygen and nutrient supply to heart muscle cells. This clogging can lead to the death of heart muscle cells, resulting in a heart attack or heart failure.

While larger blood vessels can be surgically replaced to restore blood flow, current treatments do not specifically target microvessels. These microvessels are crucial for uniform blood circulation within the heart muscle. Future safety and efficacy studies will be required before this type of treatment could become available to IHD patients. The study's journal reference is 'Topical Vascular Organoid Therapy Promotes Microvascular Regeneration and Functional Recovery in Porcine Ischemic Cardiomyopathy' in Stem Cell Reports with DOI 10.1016/j.stemcr.2026.102999.