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. 2012 Nov;1(11):792-802.
doi: 10.5966/sctm.2012-0088. Epub 2012 Oct 29.

Bioprinted amniotic fluid-derived stem cells accelerate healing of large skin wounds

Aleksander Skardal  1 , David Mack, Edi Kapetanovic, Anthony Atala, John D Jackson, James Yoo, Shay Soker
Affiliations

Bioprinted amniotic fluid-derived stem cells accelerate healing of large skin wounds

Aleksander Skardal et al. Stem Cells Transl Med. 2012 Nov.

Abstract

Stem cells obtained from amniotic fluid show high proliferative capacity in culture and multilineage differentiation potential. Because of the lack of significant immunogenicity and the ability of the amniotic fluid-derived stem (AFS) cells to modulate the inflammatory response, we investigated whether they could augment wound healing in a mouse model of skin regeneration. We used bioprinting technology to treat full-thickness skin wounds in nu/nu mice. AFS cells and bone marrow-derived mesenchymal stem cells (MSCs) were resuspended in fibrin-collagen gel and "printed" over the wound site. At days 0, 7, and 14, AFS cell- and MSC-driven wound closure and re-epithelialization were significantly greater than closure and re-epithelialization in wounds treated by fibrin-collagen gel only. Histological examination showed increased microvessel density and capillary diameters in the AFS cell-treated wounds compared with the MSC-treated wounds, whereas the skin treated only with gel showed the lowest amount of microvessels. However, tracking of fluorescently labeled AFS cells and MSCs revealed that the cells remained transiently and did not permanently integrate in the tissue. These observations suggest that the increased wound closure rates and angiogenesis may be due to delivery of secreted trophic factors, rather than direct cell-cell interactions. Accordingly, we performed proteomic analysis, which showed that AFS cells secreted a number of growth factors at concentrations higher than those of MSCs. In parallel, we showed that AFS cell-conditioned media induced endothelial cell migration in vitro. Taken together, our results indicate that bioprinting AFS cells could be an effective treatment for large-scale wounds and burns.

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Figures

Figure 1.
Figure 1.
Bioprinting stem cells for treatment of skin wounds. (A): A schematic describing the approach by which amniotic fluid-derived stem (AFS) cells are bioprinted in order to increase healing of a full-thickness skin wound. Wounds containing the deposited gels with green fluorescent protein-tagged AFS cells were harvested 24 hours postprinting and analyzed with confocal microscopy. Images revealed evenly distributed cells in the gels, as viewed from above (B) or from the side (C).
Figure 2.
Figure 2.
Wound closure rates are increased in AFS cell- and MSC-treated mice. (A): Gross histology images illustrating wound closure in gel-only, MSC, and AFS treatments. (B): Percentage of unclosed wound remaining at surgery, 1 week, and 2 weeks. Significance: *, p < .05; **, p < .01. Abbreviations: AFS, amniotic fluid-derived stem; AFSC, amniotic fluid-derived stem cell; MSC, mesenchymal stem cell.
Figure 3.
Figure 3.
Contraction and re-epithelialization rates are increased in AFS cell- and MSC-treated mice. Quantification of contraction (A) and re-epithelialization (B) at surgery, 1 week, and 2 weeks. Significance: *, p < .05; **, p < .01. Re-epithelialization was visualized by the extent of formation of keratinocyte layers in hematoxylin and eosin-stained tissue sections. (C): Poorly defined epithelium in the group treated with gel only. (D, E): Well-defined and structurally robust epithelium in MSC-treated (D) and AFS-treated (E) groups. Scale bars = 50 μm. Abbreviations: AFS, amniotic fluid-derived stem; MSC, mesenchymal stem cell.
Figure 4.
Figure 4.
AFS cells induce neovascularization and blood vessel maturation in vivo. Hematoxylin and eosin staining revealed thicker regenerating tissue with more blood vessels in the AFS and MSC groups compared with the gel-only group. (A–C): Week 1; (D–F): week 2. (A, D): Gel-only; (B, E): MSC; (C, F): AFS. Arrows: vessels. AFS cells increased the number of newly formed vessels and induced formation of larger vessels. Microvessel density (G) and vessel diameter (H) were quantified using histology images and ImageJ software. Significance: *, p < .05. AFS cells induced formation of mature blood vessels. SMA staining was seen around blood vessels in regenerated tissues of the gel-only (I), MSC (J), and AFS (K) groups. Arrows: cells expressing SMA. Extravasated RBCs were present in the gel-only (L) and MSC groups (M) but not in the AFS group (N). Scale bars = 50 μm. Abbreviations: AFS, amniotic fluid-derived stem; L, lumen; MSC, mesenchymal stem cell; R, regenerated tissue; RBC, red blood cell; S, subcutaneous tissue; SMA, smooth muscle actin.
Figure 5.
Figure 5.
AFS cells and MSCs are transient in the regenerating wound and do not permanently integrate into the tissue. Regenerating skin was harvested at days 1, 4, 7, and 14 in order to determine the presence of labeled cells. GFP-labeled AFS cells (A) and MSCs (B) were visible in decreasing numbers over the time course of the experiment. Green: GFP-expressing AFS or MSCs; blue: nuclear staining, DAPI. Scale bars = 50 μm. Abbreviations: AFS, amniotic fluid-derived stem; GFP, green fluorescent protein; MSC, mesenchymal stem cell; DAPI, 4′,6-diamidino-2-phenylindole.
Figure 6.
Figure 6.
AFS cells induce endothelial cell migration in vitro. AFS cells cultured on soft surfaces increased migration rates of HUVECs. (A–C): Crystal violet-stained HUVECs that migrated through Transwell inserts toward AFS cells cultured on soft in vivo-like substrates (A), plastic (B), or Chang's media only (C). (D): Average number of observed migrated HUVECs per field of view. Significance: *, p values between all pairwise comparisons between the three groups were less than .05. Scale bars = 50 μm. Abbreviations: AFS, amniotic fluid-derived stem; HUVEC, human umbilical vein endothelial cell.
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References

    1. Cherry DK, Hing E, Woodwell DA, et al. National Ambulatory Medical Care Survey: 2006 summary. Natl Health Stat Report. 2008:1–39. - PubMed
    1. Pitts SR, Niska RW, Xu J, et al. National Hospital Ambulatory Medical Care Survey: 2006 emergency department summary. Natl Health Stat Report. 2008:1–38. - PubMed
    1. Miller SF, Bessey P, Lentz CW, et al. National burn repository 2007 report: A synopsis of the 2007 call for data. J Burn Care Res. 2008;29:862–870. discussion 871. - PubMed
    1. Peck MD. Epidemiology of burns throughout the world. Part I: Distribution and risk factors. Burns. 2011;37:1087–1100. - PubMed
    1. Kurd SK, Hoffstad OJ, Bilker WB, et al. Evaluation of the use of prognostic information for the care of individuals with venous leg ulcers or diabetic neuropathic foot ulcers. Wound Repair Regen. 2009;17:318–325. - PMC - PubMed

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