Wound Skin Regeneration Research Articles

CD301b+ Macrophages Are Essential for Effective Skin Wound Healing

Regeneration of skin's barrier function after injury requires temporally coordinated cellular interactions between multiple cell types. Macrophages are essential inflammatory cells in skin wound regeneration. These cells switch their phenotype from inflammatory in the early regenerative stages to anti-inflammatory in the midstages of healing to coordinate skin repair. However, little is known about how different subsets of anti-inflammatory macrophages contribute to skin wound healing. Here, we characterize midstage macrophages (CD45(+)/CD11b(+)/F4-80(+)) and identify two major populations: CD206(+)/CD301b(+) and CD206(+)/CD301b(-). The numbers of CD206(+)/CD301b(+) macrophages increased concomitantly with repair, when the anti-inflammatory phenotype switch occurs in midstage healing. Using diphtheria toxin-mediated depletion models in mice, we show that selective depletion of midstage CD301b-expressing macrophages phenocopied wound healing defects observed in mice where multiple myeloid lineages are depleted. Additionally, when FACS-isolated subpopulations of myeloid cells were transplanted into 3-day wounds of syngeneic mice, only CD206(+)/CD301b(+) macrophages significantly increased proliferation and fibroblast repopulation. These data show that the CD301b-expressing subpopulation of macrophages is critical for activation of reparative processes during the midstage of cutaneous repair.

Photosensitive semiconducting polymer-incorporated nanofibers for promoting the regeneration of skin wound

Photosensitive semiconducting polymer (SP) combined with light stimulation has shown the capability in promoting the proliferation of human dermal fibroblasts (HDFs). However, the high cytotoxicity of the used SP hindered its further application in bioactive scaffolds. In this contribution, we designed and synthesized a SP, poly (N,N-bis(2-octyldodecyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene) (PDBTT) with low cytotoxicity and strong absorbance in red and near-infrared region (600–1200nm). The photosensitive SP was then applied in electrospun poly(ε-caprolactone) (PCL) nanofibrous scaffold and evaluated its proliferative effect on HDFs under the illumination from red light-emitting diode (LED) with high tissue penetration. After 9days of continuous stimulation, the hybrid electrospun PCL/PDBTT nanofibers with low cytotoxicity showed excellent support for HDFs adhesion, proliferation and collagen secretion than neat PCL nanofibers and HDFs on the stimulated PCL/PDBTT nanofibers gained typical spindle morphology, indicating the well cell spreading on the stimulated PCL/PDBTT nanofibers. The incorporation of functional materials within synthetic biomaterials could be a novel way in improving the performance of engineered tissue constructs by providing multiple cues (e.g. electrical stimulation) to the attached cells.

Recruitment of mesenchymal stem cells and macrophages by dual release of stromal cell-derived factor-1 and a macrophage recruitment agent enhances wound closure.

In this study, the wound closure of mouse skin defects was examined in terms of recruitment of mesenchymal stem cells (MSC) and macrophages. For the cells recruitment, stromal derived factor-1 (SDF-1) of a MSC recruitment agent and sphingosine-1 phosphate agonist (SEW2871) of a macrophages recruitment agent were incorporated into gelatin hydrogels, and then released in a controlled fashion. When applied to a skin wound defect of mice, gelatin hydrogels incorporating mixed 500 ng SDF-1 and 0.4, 0.8, or 1.6 mg SEW2871-micelles recruited a higher number of both MSC and macrophages than those incorporating SDF-1 or phosphate buffered saline. However, the number of M1 phenotype macrophages for the hydrogel incorporating mixed SDF-1 and SEW2871-micelles recruited was remarkably low to a significant extent compared with that for those hydrogel incorporating 0.4, 0.8, or 1.6 mg SEW2871-micelles. On the other hand, the number of M2 macrophages 3 days after the implantation of the hydrogels incorporating SDF-1 and 0.4 mg SEW2871-micelles significantly increased compared with that for other hydrogels. In vivo experiments revealed the hydrogels incorporating SDF-1 and 0.4 mg SEW2871-micelles promoted the wound closure of skin defect to a significant stronger extent than those incorporating SEW2871-micelles, SDF-1, and a mixture of SDF-1 and higher doses of SEW2871-micelles. It is concluded that the in vivo recruitment of MSC and macrophages to the defects may contribute to the tissue regeneration of skin wound.

Synergetic effect of 3,4-dihydroxy-l-phenylalanine-modified poly(lactic-co-glycolic acid) nanopatterned patch with fibroblast growth factor-2 for skin wound regeneration.

Nanoscale topography substrates have potential in guiding cell polarization and migration. Wound healing can be accelerated by nanotopographical substrates which provided appropriate direction to host cells around wound site. We fabricated biodegradable poly (lactic-co-glycolic acid) (PLGA) nanopatterned patch (nP-patch) using capillary force lithography method. Simple surface modification was applied using 3,4-dihydroxy-l-phenylalanine (LD), which has been reported as effective adhesion molecules with similar structure as mussel protein, to immobilize fibroblast growth factor-2 (FGF2) on PLGA patches. In present study, we hypothesized that nP-patch could be enhanced the cell migration in vitro by a guide of nanotopography and that nP-patch with soluble growth factor could accelerate skin wound healing in vivo. To investigate its nanotopographical effect on cell behavior, human dermal fibroblast (HDF) cells were cultured on nP-patch and flat PLGA patch (F-patch). The rate of surface coverage was measured on nP-patch with vertical or parallel orientation. The surface coverage rate was significantly enhanced by nP-patch with vertical orientation compared to the parallel orientation or the F-patch. We made a full thickness (Ø 18 mm) wound on the back of athymic mice and implanted PLGA patches with or without FGF2. FGF2-loaded nP-patch showed much faster wound closure in 21 days compared to others. Histological analysis showed that regenerated tissue had a similar structure as native skin. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 594-604, 2017.

Human Adipose Stem Cells Cell Sheet Constructs Impact Epidermal Morphogenesis in Full-Thickness Excisional Wounds

Among the wide range of strategies to target skin repair/regeneration, tissue engineering (TE) with stem cells at the forefront, remains as the most promising route. Cell sheet (CS) engineering is herein proposed, taking advantage of particular cell-cell and cell-extracellular matrix (ECM) interactions and subsequent cellular milieu, to create 3D TE constructs to promote full-thickness skin wound regeneration. Human adipose derived stem cells (hASCs) CS were obtained within five days using both thermoresponsive and standard cell culture surfaces. hASCs-based constructs were then built by superimposing three CS and transplanted into full-thickness excisional mice skin wounds with delayed healing. Constructs obtained using thermoresponsive surfaces were more stable than the ones from standard cell culture surfaces due to the natural adhesive character of the respective CS. Both CS-generating strategies lead to prolonged hASCs engraftment, although no transdifferentiation phenomena were observed. Moreover, our findings suggest that the transplanted hASCs might be promoting neotissue vascularization and extensively influencing epidermal morphogenesis, mainly through paracrine actions with the resident cells. The thicker epidermis, with a higher degree of maturation characterized by the presence of rete ridges-like structures, as well as a significant number of hair follicles observed after transplantation of the constructs combining the CS obtained from the thermoresponsive surfaces, reinforced the assumptions of the influence of the transplanted hASCs and the importance of the higher stability of these constructs promoted by cohesive cell-cell and cell-ECM interactions. Overall, this study confirmed the potential of hASCs CS-based constructs to treat full-thickness excisional skin wounds and that their fabrication conditions impact different aspects of skin regeneration, such as neovascularisation, but mainly epidermal morphogenesis.

Copper-induced change in the ESR signal of hemoglobin nitrosyl complexes in wound by the action of copper nanoparticles

The results concerning changes in the ESR signal of hemoglobin nitrosyl complexes in wound tissues in the course of healing by the action of ointments with copper nanoparticles (patent N2460532, Russia) are presented. It is shown that the wound healing process modified by the influence of copper nanoparticles demonstrates the increase in the ESR signal amplitude for :hemoglobin nitrosyl complexes as compared with controls (the ointment base without nanoparticles). Planimetric measurements of wound area through reparation course indicate an active process of wound healing for injuries treated with copper nanoparticles in the ointment, resulting in lessening half-reparation time up to 5.0 times as compared with controls (treatment with the ointment base). The paper discusses the role of copper nanoparticles, NO and their potential synergistic effect on the skin wound regeneration.

Effect of plasma flow on regeneration of skin wounds and on reactivity of the body

The aim of this investigation was to provide more research data on the behavior of the plasma scalpel, a surgical tool based on the use of the energy flow of ionized gases for the treatment of skin wounds. The effect of the ionized gas flow on wound skin wound healing was tested on three series of six rabbits. Experimental methods and results are given for the biochemical interaction of the skin with the plasma.