Hypoxic preconditioning of human urine-derived stem cell-laden small intestinal submucosa enhances wound healing potential

Xiu-Ru Zhang,Yi Zhang,Yi-Zhou Huang,Li Zhou,An-Jing Chen,Yan-Lin Jiang,Jin-Kui Pi,Jun-Gen Hu,Hui-Qi Xie,Hong-Wei Gao

doi:10.1186/s13287-020-01662-2

Abstract

BackgroundUrine-derived stem cells (USCs) are a valuable stem cell source for tissue engineering because they can be harvested non-invasively. Small intestine submucosa (SIS) has been used as scaffolds for soft tissue repair in the clinic. However, the feasibility and efficacy of a combination of USCs and SIS for skin wound healing has not been reported. In this study, we created a tissue-engineered skin graft, termed the SIS+USC composite, and hypothesized that hypoxic preconditioning would improve its wound healing potential.MethodsUSCs were seeded on SIS membranes to fabricate the SIS+USC composites, which were then cultured in normoxia (21% O2) or preconditioned in hypoxia (1% O2) for 24 h, respectively. The viability and morphology of USCs, the expression of genes related to wound angiogenesis and reepithelialization, and the secretion of growth factors were determined in vitro. The wound healing ability of the SIS+USC composites was evaluated in a mouse full-thickness skin wound model.ResultsUSCs showed good cell viability and morphology in both normoxia and hypoxic preconditioning groups. In vitro, hypoxic preconditioning enhanced not only the expression of genes related to wound angiogenesis (VEGF and Ang-2) and reepithelialization (bFGF and EGF) but also the secretion of growth factors (VEGF, EGF, and bFGF). In vivo, hypoxic preconditioning significantly improved the wound healing potential of the SIS+USC composites. It enhanced wound angiogenesis at the early stage of wound healing, promoted reepithelialization, and improved the deposition and remodeling of collagen fibers at the late stage of wound healing.ConclusionsTaken together, this study shows that hypoxic preconditioning provides an easy and efficient strategy to enhance the wound healing potential of the SIS+USC composite.

Highlights

Urine-derived stem cells (USCs) are a valuable stem cell source for tissue engineering because they can be harvested non-invasively
The cells from the pellet were seeded in 6-well plates and cultured in cell culture medium comprised of 50% Keratinocyte Serum-Free Medium (KSFM, Gibco, USA), 33.75% Dulbecco’s modified Eagle medium (DMEM, Gibco, USA), 11.25% Ham’s F-12 Nutrient Mixture (Gibco, USA), and 5% fetal bovine serum (FBS, Gibco, USA) supplemented by 5 ng/mL epidermal growth factor (EGF, Gibco, USA), 50 ng/mL bovine pituitary extract (Scienceu, USA), 0.4 μg/mL hydrocortisone (Sigma, USA), 5 μg/mL transferrin (Sigma, USA), 5 ng/mL bovine insulin (Sigma, USA), 0.18 mM adenine (Sigma, USA), 2 nM 3,3,5-triiodo-L-thyromine (Sigma, USA), 100 units/mL penicillin (Gibco, USA), and 100 μg/mL streptomycin (Gibco, USA)
The results showed that USCs distributed in the wound bed on days 4 and 7 but only a few of them participated in vascular formation (Fig. 6a)

Summary

Introduction

Urine-derived stem cells (USCs) are a valuable stem cell source for tissue engineering because they can be harvested non-invasively. USCs have many advantages for tissue engineering applications: they share biological characteristics with MSCs [5]; can be isolated from autologous urine via a simple, noninvasive, and low-cost approach [6]; and can be obtained from donors regardless of gender, age, or health condition (except for urinary tract infection or anuria) [7]. These features make USCs attractive for creating personalized grafts for tissue regeneration, and as such, a few studies have reported the use of USCs for wound healing [8, 9]

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Discussion

Conclusion