Transdifferentiation of peripheral blood mononuclear cells into epithelial-like cells

Differential DNA methylation profiles of peripheral blood mononuclear cells in allergic asthmatic children following dust mite immunotherapy

BACKGROUND/PURPOSE

Allergen-specific immunotherapy (SIT) is now considered curative to allergic diseases such as asthma. Mechanistically, our previous work showed DNA hypermethylation of cytokine genes, in T-helper cells, in allergic asthmatic children treated with allergen-SIT. In this study, we extended to work to assess possible changes in the DNA methylomes of peripheral blood mononuclear cells (PBMCs), isolated from mite allergen-SIT asthmatic children, to explore further the underlying methylation changes.

METHODS

Thirteen allergic asthmatic children who received Der p-SIT, 12 non-SIT allergic asthmatic controls, and 12 healthy controls were enrolled. Bisulfite-converted DNA from Der p-stimulated PBMCs was analyzed using Human Methylation 450 k BeadChip. Pyrosequencing and quantitative real-time PCR were used to validate the DNA methylation levels and the gene expression of individual samples.

RESULTS

We identified 108 significantly differentially methylated regions (DMRs) unique to Der p-treated PBMCs, with 53 probes linked to demethylated DMRs, and 55 probes linked to methylated DMRs. Three associated genes (BCL6, HSPG2, and HSP90AA1), of selected DMRs, were subjected to bisulfite pyrosequencing. Of these, BCL6 showed significant hypomethylation, while HSPG2 and HSP90AA1 were hypermethylated in SIT group, compared to the AA group. Furthermore, SIT group had significantly higher gene expression of BCL6 and lower gene expression of HSPG2. KEGG pathway analysis further revealed DMR genes involved in ECM-receptor interactions, asthma, and antigen processing and presentation pathways.

CONCLUSIONS

Several DNA regions showed DNA methylation altered by Der p specific immunotherapy, indicating desensitization-associated methylomes. Genes belonging to these SIT-altered pathways may represent therapeutic targets for better clinical management of asthma.

Differentiated fibrocytes assume a functional mesenchymal phenotype with regenerative potential

Fibrocytes (FCs) are hematopoietic lineage cells that migrate to sites of injury, transition to a mesenchymal phenotype, and help to mediate wound repair. Despite their relevance to human fibrotic disorders, there are few data characterizing basic FC biology. Herein, using proteomic, bioenergetic, and bioengineering techniques, we conducted deep phenotypic characterization of differentiating and mature FCs. Differentiation was associated with metabolic reprogramming that favored oxidative phosphorylation. Mature FCs had distinct proteomes compared to classic mesenchymal cells, formed functional stromae that supported epithelial maturation during in vitro organotypic culture, and exhibited in vivo survival and self-tolerance as connective tissue isografts. In an in vitro scratch assay, FCs promoted fibroblast migration and wound closure by paracrine signaling via the chemokine CXCL8 (interleukin-8). These findings characterize important aspects of FC differentiation and show that, in addition to their role in wound healing, FCs hold potential as an easily isolated autologous cell source for regenerative medicine.

Preliminary observations of a new approach to tissue repair: Peripheral blood mononuclear cells in platelet-rich plasma injected into skin graft area

Our purpose was accelerating the physiologic wound healing, stimulating tissue regeneration and the reparative tissue processes in resistant skin ulcers as in a case of an erosive lichen planus of the soles and after a surgical treatment as for severe Darier disease. The challenge was to establish an effective therapy to enhance tissue healing by the injection of a mixture of peripheral blood mononuclear cells (PB-MNCs) and platelet-rich plasma (PRP) into a skin autograft area. This new perioperative biotechnological approach enriches PRP with the effects of PB-MNCs. It offers a novel advanced strategy that could become an ideal biologic blood-derived therapy, whose components are entirely autologous and produced by a protocol independent by the operator.

Effects of corticosteroid plus long-acting beta2-agonist on the expression of PD-L1 in double-stranded RNA-induced lung inflammation in mice

Background

Airway viral infections cause the exacerbations of asthma and chronic obstructive pulmonary disease. PD-L1, also known as B7-H1, is an immune-checkpoint molecule that plays a role in an escape mechanism of viruses from the host immune systems. This escape may be associated with the persistence of viral infection and the exacerbation of the underlying diseases. In a study in vitro, we have shown that corticosteroids plus long-acting beta₂-agonists (LABAs) attenuate the upregulation of PD-L1 on airway epithelial cells stimulated with an analog of viral double-stranded RNA, polyinosinic-polycytidylic acid (poly I:C). To address its biological relevance in vivo, we investigated the effect of corticosteroid plus LABA on the expression of PD-L1 in double-stranded RNA-induced lung inflammation in mice.

Methods

Mice were intratracheally administered with poly I:C. The expression of PD-L1 on the lung cells was assessed by flow cytometry and inflammation was assessed for bronchoalveolar lavage fluid (BALF). Independent as well as combination effects of ciclesonide and indacaterol were examined.

Results

Administration of low dose poly I:C upregulated the expression of PD-L1, induced neutrophilia and increased keratinocyte-derived chemokine (KC), macrophage inflammatory protein-1β (MIP-1β), and IL-6 in BALF. The upregulation of PD-L1, neutrophilic inflammation and increase of KC were suppressed by ciclesonide plus indacaterol, but not by either when administered independently. Although the upregulation of PD-L1 by high dose poly I:C was suppressed by ciclesonide plus indacaterol, neutrophilia and increased KC, MIP-1β, and IL-6 in BALF were not attenuated.

Conclusions

Ciclesonide plus indacaterol attenuate double-stranded RNA-induced upregulation of PD-L1 in the lungs.

In vitro transdifferentiation of human skin keratinocytes to corneal epithelial cells

BACKGROUND AIMS

Skin keratinocytes (SKs) share the same surface ectodermal origin as that of corneal epithelium. In this study, the plasticity of epidermal keratinocytes was exploited to generate corneal epithelial-like cells, which might serve as an alternative source of autologous tissue for the treatment of bilateral limbal stem cell deficiency.

METHODS

Skin samples were subjected to collagenase digestion to isolate SKs and transdifferentiated to corneal epithelial-like cells using limbal fibroblast conditioned medium (LFCM). SKs and transdifferentiated corneal epithelial cells (TDCECs) were characterized using immunofluorescence and fluorescence-activated cell sorting. The propensity for expression of angiogenic genes in TDCECs was compared with cultured oral mucosal epithelial cells (COMEC) in vitro. RT(2) quantitative polymerase chain reaction profiler array was performed to study the signaling pathways involved in the transdifferentiation process.

RESULTS

The TDCECs obtained from SKs showed corneal epithelial-like morphology and expressed corneal epithelial markers, CK3 and CK12. Hematoxylin-eosin and immunohistochemistry showed stratified layers of TDCECs expressing CK 3/12, confirming the corneal epithelial phenotype. We found that the expression of several angiogenic and epithelial mesenchymal transition factors were down-regulated in TDCECs compared with COMEC, suggesting a lower capacity to induce angiogenesis in TDCECs. There was considerable difference in the signaling mechanisms between TDCECs and SKs on testing by RT(2) profiler array, signifying differences at the global gene profile. The comparison of TDCECs and limbal derived corneal epithelial cells showed similar gene expression.

DISCUSSION

Our study shows that SKs have the potential to transdifferentiate into corneal epithelial-like cells using LFCM.

DMBA/TPA treatment is necessary for BCC formation from patched deficient epidermal cells in Ptch(flox/flox)CD4Cre(+/-) mice

The development of basal cell carcinoma (BCC), the most frequently diagnosed tumor among persons with European ancestry, is closely linked to mutations in the Hedgehog (Hh) receptor and tumor suppressor Patched1 (Ptch). Using Ptch(flox/flox)CD4Cre(+/-) mice, in which Ptch was ablated in CD4Cre-expressing cells, we demonstrate that the targeted cells can give rise to BCC after treatment with DMBA (7,12-dimethylbenz(a)anthracene)/TPA (12-O-tetradecanoylphorbol-13-acetate), but not after wounding of the skin. In addition, in this model, BCC are not caused by malfunctioning of Ptch-deficient T cells, as BCC did not develop when bone marrow (BM) of Ptch(flox/flox)CD4Cre(+/-) mice was transplanted into Ptch wild-type mice. Instead, lineage-tracing experiments and flow cytometric analyses suggest that the tumors are initiated from rare Ptch-deficient stem cell-like cells of the epidermis that express CD4. As DMBA/TPA is a prerequisite for BCC development in this model, the initiated cells need a second stimulus for expansion and tumor formation. However, in contrast to papilloma, this stimulus seems to be unrelated to alterations in the Ras signaling cascade. Together, these data suggest that biallelic loss of Ptch in CD4(+) cells does not suffice for BCC formation and that BCC formation requires a second so far unknown event, at least in the Ptch(flox/flox)CD4Cre(+/-) BCC mouse model.

Transdifferentiation of adipose-derived stem cells into keratinocyte-like cells: engineering a stratified epidermis

Skin regeneration is an important area of research in the field of tissue-engineering, especially for cases involving loss of massive areas of skin, where current treatments are not capable of inducing permanent satisfying replacements. Human adipose-derived stem cells (ASC) have been shown to differentiate in-vitro into both mesenchymal lineages and non-mesenchymal lineages, confirming their transdifferentiation ability. This versatile differentiation potential, coupled with their ease of harvest, places ASC at the advancing front of stem cell-based therapies. In this study, we hypothesized that ASC also have the capacity to transdifferentiate into keratinocyte-like cells and furthermore are able to engineer a stratified epidermis. ASC were successfully isolated from lipoaspirates and cell sorted (FACS). After sorting, ASC were either co-cultured with human keratinocytes or with keratinocyte conditioned media. After a 14-day incubation period, ASC developed a polygonal cobblestone shape characteristic of human keratinocytes. Western blot and q-PCR analysis showed the presence of specific keratinocyte markers including cytokeratin-5, involucrin, filaggrin and stratifin in these keratinocyte-like cells (KLC); these markers were absent in ASC. To further evaluate if KLC were capable of stratification akin to human keratinocytes, ASC were seeded on top of human decellularized dermis and cultured in the presence or absence of EGF and high Ca²⁺ concentrations. Histological analysis demonstrated a stratified structure similar to that observed in normal skin when cultured in the presence of EGF and high Ca²⁺. Furthermore, immunohistochemical analysis revealed the presence of keratinocyte markers such as involucrin, cytokeratin-5 and cytokeratin-10. In conclusion this study demonstrates for the first time that ASC have the capacity to transdifferentiate into KLC and engineer a stratified epidermis. This study suggests that adipose tissue is potentially a readily available and accessible source of keratinocytes, particularly for severe wounds encompassing large surface areas of the body and requiring prompt epithelialization.

Evidence of a role for fibrocyte and keratinocyte-like cells in the formation of hypertrophic scars

Burn injuries affect millions of people every year, and dermal fibrosis is a common complication for the victims. This disfigurement has functional and cosmetic consequences and many research groups have made it the focus of their work to understand the mechanisms that underlie its development. Although significant progress has been made in wound-healing processes, the complexity of events involved makes it very difficult to come up with a single strategy to prevent this devastating fibrotic condition. Inflammation is considered one predisposing factor, although this phase is a necessary aspect of the wound-healing process. Inflammation, driven by infiltrated immune cells, begins minutes after the burn injury and is the prevalent phase of wound healing in the early stages. Accompanying the inflammatory infiltrate, there is evidence that subpopulations of bone marrow-derived cells are also present. These populations include fibrocytes and keratinocyte-like cells, derivatives of CD14 monocytes, a component of the peripheral blood mononuclear cell infiltrate. There is evidence that these cells contribute to regeneration and repair of the wound site, but it is interesting to note that there are also reports that these cells can have adverse effects and may contribute to the development of dermal fibrosis. In this article, the authors present a review of the origin and transdifferentiation of these cells from bone marrow stem cells, the environments that direct this transdifferentiation, and evidence to support their role in fibrosis, as well as potential avenues for therapeutics to control their fibrotic effects.

Identification of p63+ keratinocyte progenitor cells in circulation and their matrix-directed differentiation to epithelial cells

Introduction

In the event of chronic diabetes or burn wounds, accomplishing skin regeneration is a major concern. Autologous skin grafting is the most effective remedy, but the tissue harvest may create more nonhealing wounds. Currently available skin substitutes have a limited clinical outcome because of immune reactions arising from the xenobiotic scaffold or allogenous cells. Autologous stem cells that can be collected without an additional injury may be a viable option for skin-tissue engineering. Presence of a low number of keratinocyte progenitor cells (KPCs) within the peripheral blood mononuclear cell (PBMNC) population has been indicated. Identification, isolation, expansion, and differentiation of KPCs is necessary before they are considered for skin regeneration, which is the focus of this study.

Methods

Culture of isolated human PBMNCs on a cell-specific matrix was carried out to induce differentiation of KPCs. Flow cytometry and reverse transcriptase polymerase chain reaction were done for epithelial stem cell marker p63 and lineage markers cytokeratin 5 and cytokeratin 14, to track differentiation. Proliferation was confirmed by quantifying the proliferating cell nuclear antigen-expressing cells. Immunostaining with epithelial cell markers, involucrin and filaggrin, was carried out to establish terminal differentiation. Microscopic analysis confirmed growth and survival of KPCs on the dermal fibroblast monolayer and on a transplantable fibrin sheet.

Results

We demonstrated that KPCs are p63⁺ and CD34^-. The specifically designed composition of the extracellular matrix was found to support selective adhesion, proliferation, and differentiation of p63⁺ KPCs. The PBMNC culture for 12 days under controlled conditions resulted in a homogenous population that expressed cytokeratins, and >90% of the cells were found to proliferate. Subculture for 5 days resulted in expression of filaggrin and involucrin, suggesting terminal differentiation. Transfer of matrix-selected KPCs to a dermal fibroblast monolayer or fibrin supported cell proliferation and showed typical hexagonal morphology of keratinocytes within 15 days.

Conclusions

Circulating KPCs were identified with p63, which differentiated into keratinocytes with expression of the cytokeratins, involucrin and filaggrin. Components of the specifically designed matrix favored KPC attachment, directed differentiation, and may turn out to be a potential vehicle for cell transplantation.

The multi-differentiation potential of peripheral blood mononuclear cells

Peripheral blood is a large accessible source of adult stem cells for both basic research and clinical applications. Peripheral blood mononuclear cells (PBMCs) have been reported to contain a multitude of distinct multipotent progenitor cell populations and possess the potential to differentiate into blood cells, endothelial cells, hepatocytes, cardiomyogenic cells, smooth muscle cells, osteoblasts, osteoclasts, epithelial cells, neural cells, or myofibroblasts under appropriate conditions. Furthermore, transplantation of these PBMC-derived cells can regenerate tissues and restore function after injury. This mini-review summarizes the multi-differentiation potential of PBMCs reported in the past years, discusses the possible mechanisms for this multi-differentiation potential, and describes recent techniques for efficient PBMC isolation and purification.

Cellular/extracellular matrix cross-talk in scar evolution and control

The principles of scar evolution and control are recognized and defined. Further clarity has been shed on these principles with the elucidation and elaboration of the sequence of events occurring at a molecular level. Cellular cross-talk among structures in the cell cytosol, in the cellular nucleus, and outside the cell within in the extracellular matrix is continuous and controlling in nature. This interaction or "dynamic reciprocity" takes place via a series of signals, ionic messenger shifts, protein activation, and receptor transactions. The described principles are now able to be defined in terms of cellular/extracellular matrix interactions and the identification of the cross-talk involved in scar evolution and maturation presents the possibility of influencing the "wording" of this cross-talk to improve scar outcome. The principles of mechanostimulation and scar support, hydration occlusion, controlled inflammation, and collagen/extracellular remodeling are discussed with possible interventions in each category.

Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The number of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1-5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min and the viability of the blank DCs (i.e. without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH(2)(+)) or negative (COOH(-)) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the number of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.

Reprogrammed fibrocytes induce a mixed Th1/Th2 cytokine response of naïve CD4(+) T cells

Naïve CD4(+) T cells develop different effector T cells and cytokine profiles after antigenic stimulation. It has been previously documented that fibrocytes function as antigen presenting cells inducing proliferation as well as Th2 cytokine response in naïve CD4(+) T cells. Our group has reported that several circulating cell types recruited to the wound site can be transformed into anti-fibrotic profile cells, which subsequently induce MMP-1 stimulation in dermal fibroblasts. Here, we report how similar reprogramming pathway of fibrocytes could modify the CD4(+) T cell response. Our findings confirmed that reprogrammed fibrocytes induce CD4(+) T cell activation with a mixed Th1/Th2 cytokine response. Since a reciprocal positive feedback between Th2 cells and fibrocytes exist to amplify and perpetuate the pro-fibrotic stimulation in dermal fibroblasts, the novel transdifferentiation of regular mature fibrocytes into reprogrammed fibrocytes appears to be a promising strategy to reverse the Th2 cytokine overproduction, and subsequently control the local fibrogenesis.

Fibrocytes can be reprogrammed to promote tissue remodeling capacity of dermal fibroblasts

Fibroblasts play a pivotal role in wound healing process participating in both tissue fibrosis and remodeling. However, it remains unclear which factors activate such diversity of fibroblast responses and how this decision-making process is made. Previous reports have demonstrated that wound milieu stimulates the transformation of circulating precursor cells into fibrocytes. These pro-fibrogenic cells promote the collagen production by resident fibroblasts. Conversely, recruited cells with anti-fibrogenic profile that can compete with fibrocytes have not been identified. This report describes a novel transdifferentiation process of fibrocytes induced by changing culture conditions. The reprogrammed fibrocytes markedly increased cell proliferation and MMP-1 expression in dermal fibroblasts. The MMP-1 up-regulation was directly related to the number of fibrocytes that followed this cell transformation. In vitro and in vivo results have confirmed that TGF-β deprivation plays an important role in this novel fibrocyte differentiation pathway. Our findings demonstrate that, changing the fibrocyte commitment, it is possible to exponentially stimulate the tissue remodeling capacity of dermal fibroblasts. These results will open new research approaches to understand the role of cell transdifferentiation and local environment not only in the wound healing process of skin, but also in several other fibrocyte-associated diseases such as lung fibrosis, asthma, liver cirrhosis, chronic pancreatitis, and atherosclerosis.

Transdifferentiated circulating monocytes release exosomes containing 14-3-3 proteins with matrix metalloproteinase-1 stimulating effect for dermal fibroblasts

Fibroblasts are major cellular components of healing wounds. In this regard, it remains to be fully understood how different paracrine signals may influence the final collagen/matrix metalloproteinase (MMP) balance in resident fibroblasts. Our previous reports have demonstrated that circulating stem cells and monocytes can be transdifferentiated into "keratinocyte-like cells" under certain culture conditions. These transformed cells are able to stimulate MMP-1 expression in dermal fibroblasts. However, the underlying mechanism of this cell-to-cell interaction is unknown. This study describes exosomes as a major delivery system that keratinocyte-like cells use to release proteins into the conditioned media. The exosomes exhibited distinctive size, density, and saucer-like morphology. Using PKH-26 and GFP-adenovirus infection, we demonstrated that exosomes are able to fuse and then release their protein content into dermal fibroblasts. Mass spectrometry and Western blotting identified five 14-3-3 isoforms (beta, gamma, epsilon, tau, and zeta) as MMP-1 stimulating factors for dermal fibroblasts. Immunoprecipation assays confirmed that these 14-3-3 isoforms account for almost the entire MMP-1 up-regulation induced by exosomes. In summary, our results demonstrated that circulating monocytes stimulated to be transformed into "keratinocyte-like cells" could promote an anti-fibrogenic commitment of dermal fibroblasts via exosomal 14-3-3 proteins.

Recovery of multipotent progenitors from the peripheral blood of patients requiring extracorporeal membrane oxygenation support

RATIONALE

Studies have demonstrated that bone marrow-derived cells can be recruited to injured lungs through an unknown mechanism. We hypothesize that marrow progenitors are mobilized into the circulation of patients with cardiac and/or respiratory failure, and may then traffic to and incorporate into the sites of tissue injury.

OBJECTIVES

To determine whether progenitor populations are increased in the blood of patients with severe acute cardiorespiratory failure placed on extracorporeal membrane oxygenation (ECMO).

METHODS

Mononuclear cells from ECMO, umbilical cord, and control blood samples were evaluated in colony-forming assays for hematopoietic, mesenchymal, and epithelial cells. Progenitors were identified by proliferative and differentiative capacities, and confirmed by the expression of lineage-specific markers.

MEASUREMENTS AND MAIN RESULTS

Significantly higher levels of hematopoietic progenitors were observed in ECMO (n = 41) samples than neonatal intensive care unit (n = 16) or pediatric intensive care unit controls (n = 14). Hematopoietic progenitor mobilization increased with time on ECMO support. Mesenchymal progenitors (MSC) were recovered from 18/58 ECMO samples with rapid sample processing (< 4 h) critical to their recovery. MSC were not recovered from normal controls. ECMO-derived MSC had osteogenic, chondrogenic, and adipogenic differentiation potential. The recovery of MSC did not influence survival outcome (61%). Epithelial progenitors were observed in eight ECMO samples but not in control samples. Their presence was associated with a lower survival trend (38%).

CONCLUSIONS

Hematopoietic, mesenchymal, and epithelial progenitors were mobilized into the circulation of patients on ECMO. This may reflect a response to severe cardiopulmonary injury, blood-foreign surface interactions with the ECMO circuit, and/or hemodilution.

Circulating monocytes have the capacity to be transdifferentiated into keratinocyte-like cells

Transdifferentiation is a process in which the original commitment of a cell is changed to give rise to unexpected peripheral mature cells. Our previous report showed that circulating stem cells can generate keratinocyte-like cells (KLCs). However, it remains to be determined whether or not other peripheral blood mononuclear cells (PBMC) subsets have the potential to follow the same cell fate. In this study, the cell transdifferentiation of circulating CD14(+) monocytes into KLCs and their regulatory effect on matrix metalloproteinase-1 (MMP-1) expression in dermal fibroblasts were evaluated. The results showed that monocytes isolated from peripheral blood mononuclear cells have the capacity to generate KLCs. These transdifferentiated cells exhibited, along with a keratinocyte-like morphology, a characteristic profile consisting in stratifin(+), cytokeratins(+) (types I and II), CD14(low), and involucrin(+) on day 21 in culture. Similar to keratinocyte-conditioned media, KLC-derived conditioned media were able to induce an increase in the MMP-1 expression in dermal fibroblasts. This effect was significantly reduced by using 14-3-3 protein-depleted KLC-conditioned media. Our findings show the potential transdifferentiation of circulating CD14(+) monocytes into KLCs and their regulatory effect on MMP-1 expression in dermal fibroblasts.

Cell therapy based on adipose tissue-derived stromal cells promotes physiological and pathological wound healing

OBJECTIVE

We hypothesized that adipose tissue may contain progenitors cells with cutaneous and angiogenic potential.

METHODS AND RESULTS

Adipose tissue-derived stroma cells (ADSCs) were administrated to skin punched wounds of both nonirradiated and irradiated mice (20 Gy, locally). At day 14, ADSCs promoted dermal wound healing and enhanced wound closure, viscolesticity, and collagen tissue secretion in both irradiated and nonirradiated mice. Interestingly, GFP-positive ADSCs incorporated in dermal and epidermal tissue in vivo and expressed epidermal markers K5 and K14. Cultured ADSCs in keratinocyte medium have been shown to differentiate into K5- and K14-positive cells and produced high levels of KGF. At Day 7, ADSCs also improved skin blood perfusion assessed by laser Doppler imaging, capillary density, and VEGF plasma levels in both irradiated and nonirradiated animals. GFP-positive ADSCs incorporated into capillary structures in vivo and expressed the endothelial cell marker CD31. Finally, in situ interphase fluorescence hybridization showed that a small number of ADSCs have the potential to fuse with endogenous keratinocytes.

CONCLUSIONS

ADSCs participate in dermal wound healing in physiological and pathological conditions by their ability to promote reepithelialization and angiogenesis. Hence, adipose lineage cells represent a new cell source for therapeutic dermal wound healing.