Stem cell therapies are a promising approach to treating conditions such as critical limb ischemia, where blood flow is compromised due to blocked vessels. However, current therapies face challenges such as low cell viability and short lifespan of transplanted cells. Researchers are now focusing on using scaffold materials to enhance the effectiveness of stem cell treatments. By incorporating stem cells into collagen hydrogels, they have created three-dimensional constructs that significantly improve cell survival and promote blood vessel generation in ischemic tissue. In animal studies, these constructs have shown a 40% increase in blood perfusion rate and a 60% increase in limb salvage ratio compared to cell-only treatments. This innovative approach holds great promise for enhancing the therapeutic potential of stem cell therapies in treating vascular diseases.
Critical limb ischemia is a condition in which the main blood vessels supplying blood to the legs are blocked, causing blood flow to gradually decrease as atherosclerosis progresses in the peripheral arteries. Current treatments include angioplasty procedures such as stent implantation and anti-thrombotic drugs, but there is a risk of blood vessel damage and recurrence of blood clots, which is why there is a strong interest in developing a treatment using stem cells.
Stem cell therapies have high tissue regeneration capabilities, but when stem cells are transplanted alone, hypoxia at the site of injury, immune responses, and other factors can reduce cell viability and prevent the desired therapeutic effect. Therefore, it is necessary to develop a material that delivers stem cells using biodegradable polymers or components of extracellular matrix as a support to increase cell viability.
Researchers processed collagen hydrogels to micro-scale to create porous, three-dimensional scaffolds that are easy to inject in the body and have a uniform cell distribution. Collagen, a component of the extracellular matrix, has excellent biocompatibility and cellular activity, which can induce cell self-assembly by promoting interactions between the microgel particles and collagen receptors on stem cells. In addition, the spacing between microgel particles increased the porosity of the three-dimensional constructs, improving delivery efficiency and cell survival.
The microgel-cell constructs developed by the researchers expressed more pro-angiogenic factors and exhibited higher angiogenic potential than cell-only constructs. When microgel-cell constructs were injected into the muscle tissue of mice with critical limb ischemia, blood perfusion rate increased by about 40% and limb salvage ratio increased by 60% compared to the cell-only constructs, confirming their effectiveness in increasing blood flow and preventing necrosis in the ischemic limb.
