Published online Dec 26, 2018. doi: 10.4252/wjsc.v10.i12.212
Peer-review started: August 9, 2018
First decision: August 31, 2018
Revised: October 18, 2018
Accepted: November 7, 2018
Article in press: November 7, 2018
Published online: December 26, 2018
Peripheral artery disease (PAD) is caused by peripheral artery obstruction, which may lead to ischemic changes in the extremities. In advanced PAD, revascularization surgery is indicated for large to medium-sized peripheral arteries with obstructions. However, ideal treatment for small arteries with obstructions has not been established until now.
Therapeutic angiogenesis provides a novel strategy for managing PAD. Mesenchymal stem cells can be used to promote tissue angiogenesis. Among all mesenchymal stem cells, adipose-derived stem cells (ADSCs) are plentiful, easy to retrieve with less donor site morbidity, and free from ethical concerns, making it a good candidate for therapeutic angiogenesis. Fetal bovine serum (FBS) is widely used in research settings for culturing ADSCs. However, culturing cells for therapeutic purposes in patients is associated with zoonotic disease transmission and xeno-immunization concerns. Platelet-rich plasma (PRP) is an autologous reservoir of growth factors and cytokines, which have great potential to replace animal serum as culture medium.
To date, limited data are available on the effects of PRP on ADSCs. Our study evaluated the angiogenic potential of PRP-preconditioned ADSCs. In addition, ADSCs’ biological characteristics and their capability to induce angiogenesis both in vitro and in vivo were evaluated.
ADSCs were divided based on culture medium: 2.5% PRP, 5% PRP, 7.5% PRP, 10% PRP, or FBS as control. In vitro, we studied the cell proliferation rate, endothelial cell specific genes expression and cell morphology change. In vivo, we studied the angiogenic capability of ADSCs by mouse ischemic hindlimb mode.
The proliferation rate of ADSCs was higher in the 2.5%, 5%, and 7.5% PRP groups. The expression of hypoxia-inducible factor, CD31, vascular endothelial growth factor, and endothelial cell nitric oxide synthase increased in the 5% and 7.5% PRP groups. The 5%, 7.5%, and 10% PRP groups showed higher abilities to promote both CD31 and vascular endothelial growth factor production and tubular structure formation in ADSCs. According to laser Doppler perfusion scan, the perfusion ratios of ischemic limb to normal limb were significantly higher in the 5% PRP, 7.5% PRP and human umbilical vein endothelial cell groups compared with the negative control and FBS groups.
Our results showed that PRP-preconditioned ADSCs had a better ability to present endothelial cell characteristics in vitro. After PRP treatment, ADSCs significantly improved blood perfusion in ischemic hindlimbs. Furthermore, 5% PRP- and 7.5% PRP-preconditioned ADSCs exert the optimal angiogenic effect both in intro and in vivo.
We were the first study to observe the angiogenic effect of PRP-preconditioned ADSCs on ischemic hindlimb models. We were also the first to discuss the correlation between PRP concentration and angiogenesis of ADSCs. Based on our results, we believe that PRP and ADSCs could be clinically applied for treating ischemic tissues and promoting wound healing in the future. Further research should focus on increasing the rate of ADSC differentiation into mature endothelial cells and finding key regulators for three-dimensional tubular structure formation in these cells. The optimal goal is to use ADSCs to form stable and functional vessels for patients with PAD.