Vascular Organoids to Regrow Microvessels in Heart Tissue
Researchers here describe an approach to encouraging regrowth of small vessels in heart tissue, involving transplantation of organoids composed of the various cell types needed to form new vessels. Like other cell therapy strategies for an injured or aged heart, delivery involves making a patch of pseudo-tissue that is layered onto the surface of the heart. The patch mimics enough of the function of a natural extracellular matrix to increase survival of transplanted cells. More generally, we might consider whether this sort of strategy would work for other tissues; loss of capillary density is a feature of aging throughout the body, and ways to restore a more youthful extent of capillary networks could be meaningfully beneficial.
Ischemic heart disease (IHD), also known as coronary artery disease, is a leading cause of death and morbidity. IHD arises when blood vessels of the heart become clogged, blunting oxygen and nutrient supply to heart muscle cells, which eventually die off, leading to heart attack or heart failure. Although larger blood vessels can be replaced surgically to restore blood flow, there is currently no treatment targeting smaller blood vessels, so-called microvessels, which are essential for the uniform blood circulation within the heart muscle.
Researchers made vascular organoids, which are small aggregates of cells capable of forming new blood vessels, from endothelial progenitor cells (EPCs) isolated from human blood and mesenchymal stem cell-derived smooth muscle cells (SMCs) from human bone marrow. The team then placed patches of vascular organoids onto the outer heart surface of pigs with IHD and followed them for four weeks. Encouragingly, heart function in pigs receiving organoid patches was improved compared to untreated animals, and progression of IHD towards heart failure was mitigated. The organoid patches survived for several weeks and individual cells from the surface patches were found in deeper layers of the pig hearts suggesting they are migrating into the heart.
Hope it can extend life of transplanted organs that malfunctions.