Mesenchymal stem cells induce dermal fibroblast responses to injury

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury.     

Transforming growth factor-beta 1 in adipose derived stem cells conditioned medium is a dominant paracrine mediator determines hyaluronic acid and collagen expression profile

Conditioned medium from adipose derived stem cells (ADSC-CM) stimulates both collagen synthesis and migration of fibroblasts, and accelerates wound healing in vivo. Recently, the production and secretion of growth factors has been identified as an essential function of adipose-derived stem cells (ADSCs). However, the main soluble factor of ADSC-CM which mediates paracrine effects and its underlying mechanism has not been elucidated yet. In this study, we considered transforming growth factor-beta1 (TGF-β1) as a strong candidate for paracrine effect of ADSC-CM and investigated collagen synthesis and hyaluronic acid synthase (HAS) expression. After ADSC-CM addition, collagen type I, type III, HAS and hyaluronic acid (HA) expressions on human dermal fibroblasts (HDFs) were evaluated. Furthermore, to clarify effects of TGF-β1 as a paracrine mediator, TGF-β1 antibody and external supplementary TGF-β1 were treated to HDFs. Collagens type I, type III, HAS-1 and HAS-2 mRNA expressions of HDFs were greatly increased by ADSC-CM treatment, however there was no change in TGF-β1 antibody treated HDFs compared with non-treated control. These results strongly demonstrate that TGF-β1 plays an important role as a paracrine mediator of ECM synthesis. The fact that TGF-β1 contained in ADSC-CM not only accelerates collagen deposition but also increase hyaluronic acid synthesis of HDFs through HAS-1 and HAS-2 expression was also elucidated in this study. Therefore, ADSC-CM shows promise for the treatment of cutaneous wounds and accelerates granulation formation during healing process.     

Effect of age and hypoxia on TGFbeta1 receptor expression and signal transduction in human dermal fibroblasts: impact on cell migration.

Wound healing is critically affected by age, ischemia, and growth factors such as TGFbeta1. The combined effect of these factors on fibroblast migration, an essential component of wound healing, is poorly understood. To address this deficiency, we examined expression of TGFbeta receptor type I and II (TGFbetaRI and RII) under normoxia or hypoxia (1% O(2)) in cultured human dermal fibroblasts (HDFs) from young (ages 24-33) and aged (ages 61-73) adults. TGFbetaRI and RII expression was similar in both groups under normoxia. Hypoxia did not alter receptor levels in young HDFs but significantly decreased TGFbetaRI in aged cells (12 and 43%, respectively). Additionally, young cells displayed a 50% increase in activation of p42/p44 mitogen-activated kinase by TGFbeta1 (2-200 pg/ml) under hypoxia while aged cell levels of active p42/p44 decreased up to 24%. To determine functional outcomes of these findings, we measured the migratory capacity of the cells on type I collagen using a gold salt migration assay. Hypoxia increased the migratory index (MI) of young HDFs over normoxia by 30% but had no effect on aged cells. Under normoxia, TGFbeta1 (1-1000 pg/ml) increased young HDF migration in a concentration-dependent manner up to 109% over controls but minimally increased aged HDF migration (37%). Under hypoxia, TGFbeta1 significantly increased young cell MI at all concentrations but was without effect on the aged HDF response. These data demonstrate that aged fibroblasts have an impaired migratory capacity with complete loss of responsiveness to hypoxia and deficits in the migratory and signal transduction responsiveness to TGFbeta1 that may partly explain diminished healing capabilities often observed in aged patients.     

Paracrine factors of mesenchymal stem cells recruit macrophages and endothelial lineage cells and enhance wound healing

Bone marrow derived mesenchymal stem cells (BM-MSCs) have been shown to enhance wound healing; however, the mechanisms involved are barely understood. In this study, we examined paracrine factors released by BM-MSCs and their effects on the cells participating in wound healing compared to those released by dermal fibroblasts. Analyses of BM-MSCs with Real-Time PCR and of BM-MSC-conditioned medium by antibody-based protein array and ELISA indicated that BM-MSCs secreted distinctively different cytokines and chemokines, such as greater amounts of VEGF-alpha, IGF-1, EGF, keratinocyte growth factor, angiopoietin-1, stromal derived factor-1, macrophage inflammatory protein-1alpha and beta and erythropoietin, compared to dermal fibroblasts. These molecules are known to be important in normal wound healing. BM-MSC-conditioned medium significantly enhanced migration of macrophages, keratinocytes and endothelial cells and proliferation of keratinocytes and endothelial cells compared to fibroblast-conditioned medium. Moreover, in a mouse model of excisional wound healing, where concentrated BM-MSC-conditioned medium was applied, accelerated wound healing occurred compared to administration of pre-conditioned or fibroblast-conditioned medium. Analysis of cell suspensions derived from the wound by FACS showed that wounds treated with BM-MSC-conditioned medium had increased proportions of CD4/80-positive macrophages and Flk-1-, CD34- or c-kit-positive endothelial (progenitor) cells compared to wounds treated with pre-conditioned medium or fibroblast-conditioned medium. Consistent with the above findings, immunohistochemical analysis of wound sections showed that wounds treated with BM-MSC-conditioned medium had increased abundance of macrophages. Our results suggest that factors released by BM-MSCs recruit macrophages and endothelial lineage cells into the wound thus enhancing wound healing.     

Cytogentic analysis of human dermal fibroblasts (HDFs) in early and late passages using both karyotyping and comet assay techniques

Human dermal fibroblasts (HDFs) are a potential source of somatic cells for genetic manipulation and tissue engineering. Confirmation of cytogenetic stability of these cells is an essential step for cell nuclear transfer and generation of a suitable and functional induced pluripotent stem cells line. HDF cells were isolated and cultured from human foreskin samples. Cytogenetic stability of these cells was evaluated in early (3–4) and late (10–15) passages using karyotype test and alkaline comet assay techniques. HDF cells in early and late passages showed normal karyotype but by comet assay abnormality and DNA damages in late passages of HDFs were observed. Also, the parameters of alkaline comet assay in early passages of HDFs compared with late passages and positive control groups more significantly were different (p < 0.05). These findings indicate that single-strand breaks or DNA damage after many passages may have occurred in HDF cells. Our results demonstrate that only early passages of HDF cells maintain cytogenetic stability and are good candidates for gene reprogramming. In conclusion, karyotype testing alone can not be used for detection of all signs of cytogenetic abnormality and DNA damages of cells. So, for precise evaluation of DNA damage and cytogenetic instability of fibroblast cells comet assay and karyotype techniques could complement each other.     

Serum-derived exosomes accelerate scald wound healing in mice by optimizing cellular functions and promoting Akt phosphorylation

Wound exudate holds great clinical and research potential in wound repair via paracrine signaling. In essence, exudate is modified serum that contains a high concentration of exosomes. The aim of this study was to investigate the role of serum-derived exosomes in scald wound healing of NIH mice skin and to explore the underlying mechanisms. Hence, we constructed a deep second-degree scald model in NIH mice, testing the benefits of exosomes in the scald wound healing. The scratch wound assay, apoptosis assay and MTT assay were conducted to assess the effects of serum-derived exosomes on migration, apoptosis and proliferation of HaCaT cells and fibroblasts. Our results showed that serum-derived exosomes injected subcutaneously entered cells and effectively accelerated wound healing processes in mice. Additionally, serum-derived exosomes optimized functions of cells related to skin injury repair by stimulating fibroblast proliferation, promoting HaCaT cell migration, and suppressing apoptosis of HaCaT cells induced by heat stress. Further study revealed that serum-derived exosomes enhanced phosphorylation of the serine-threonine kinase Akt in scalded skin tissue. These results suggest a potential clinical use of serum-derived exosomes for treating skin scald.

     

Proliferation and motility of HaCaT keratinocyte derivatives is enhanced by fibroblast nemosis

The role of paracrine tumor-stroma regulation in the progression of cancer is under intense investigation. Activated fibroblasts are key components of the tumor microenvironment providing the soluble factors mediating the regulation. Nemosis is an experimental model to study these parameters: formation of a multicellular spheroid activates fibroblasts and leads to increased production of soluble factors involved in the promotion of growth and motility. Role of nemosis was investigated in the tumorigenesis of HaCaT derivatives representing skin carcinoma progression. Conditioned medium from fibroblast spheroids increased proliferation rate of HaCaT derivatives. Expression of proliferation marker Ki-67 increased significantly in benign A5 and low-grade malignant II-4 cells, but did not further increase in the metastatic RT3 cells. Expression of p63, keratinocyte stem cell marker linked to cancer progression, was augmented by medium from nemotic fibroblasts; this increase was also seen in RT3 cells. Scratch-wound healing of the keratinocytes was enhanced in response to fibroblast nemosis. Neutralizing antibodies against growth factors inhibited wound healing to some extent; the response varied between benign and malignant keratinocytes. Migration and invasion were enhanced by conditioned medium from nemotic fibroblasts in benign and low-grade malignant cells. RT3 keratinocyte migration was further augmented, but invasion was not, indicating their intrinsic capacity to invade. Our data demonstrate that fibroblast nemosis increases proliferation and motility of HaCaT keratinocyte derivatives, and thus nemosis can be used as a model to study the role of soluble factors secreted by fibroblasts in tumor progression.     

Induction of MMP-9 release from human dermal fibroblasts by thrombin: involvement of JAK/STAT3 signaling pathway in MMP-9 release

Background:  

It has been recognized that dermal fibroblasts and matrix metalloproteases (MMP) play crucial roles in wound healing process in skin. Thrombin was found to stimulate IL-8 release from human dermal fibroblasts (HDFs). However, little is known of the effect of thrombin on secretion of MMPs from dermal fibroblasts. In the present study, the influence of thrombin on proMMP-2 and proMMP-9 activity release from primary cultured HDFs, and its potential signaling pathways were investigated.     

Comparison between the cultures of human induced pluripotent stem cells (hiPSCs) on feeder-and serum-free system (Matrigel matrix), MEF and HDF feeder cell lines

Human induced pluripotent stem cells (hiPSCs) are a type of pluripotent stem cells artificially derived from an adult somatic cell (typically human fibroblast) by forced expression of specific genes. In recent years, different feeders like inactivated mouse embryonic fibroblasts (MEFs), human dermal fibroblasts (HDFs), and feeder free system have commonly been used for supporting the culture of stem cells in undifferentiated state. In the present work, the culture of hiPSCs and their characterizations on BD Matrigel (feeder-and serum-free system), MEF and HDF feeders using cell culture methods and molecular techniques were evaluated and compared. The isolated HDFs from foreskin samples were reprogrammed to hiPSCs using gene delivery system. Then, the pluripotency ability of hiPSCs cultured on each layer was determined by teratoma formation and immunohistochemical staining. After EBs generation the expression level of three germ layers genes were evaluated by Q-real-time PCR. Also, the cytogenetic stability of hiPSCs cultured on each condition was analyzed by karyotyping and comet assay. Then, the presence of pluripotency antigens were confirmed by Immunocytochemistry (ICC) test and alkaline phosphatase staining. This study were showed culturing of hiPSCs on BD Matrigel, MEF and HDF feeders had normal morphology and could maintain in undifferentiated state for prolonged expansion. The hiPSCs cultured in each system had normal karyotype without any chromosomal abnormalities and the DNA lesions were not observed by comet assay. Moreover, up-regulation in three germ layers genes in cultured hiPSCs on each layer (same to ESCs) compare to normal HDFs were observed (p < 0.05). The findings of the present work were showed in stem cells culturing especially hiPSCs both MEF and HDF feeders as well as feeder free system like Matrigel are proper despite benefits and disadvantages. Although, MEFs is suitable for supporting of stem cell culturing but it can animal pathogens transferring and inducing immune response. Furthermore, HDFs have homologous source with hiPSCs and can be used as feeder instead of MEF but in therapeutic approaches the cells contamination is a problem. So, this study were suggested feeder free culturing of hiPSCs on Matrigel in supplemented media (without using MEF conditioned medium) resolves these problems and could prepare easy applications of hiPSCs in therapeutic approaches of regenerative medicine such as stem-cell therapy and somatic cell nuclear in further researches.     

Endoglin Haploinsufficiency Promotes Fibroblast Accumulation during Wound Healing through Akt Activation

Accurate regulation of dermal fibroblast function plays a crucial role in wound healing. Many fibrotic diseases are characterized by a failure to conclude normal tissue repair and the persistence of fibroblasts inside lesions. In the present study we demonstrate that endoglin haploinsufficiency promotes fibroblast accumulation during wound healing. Moreover, scars from endoglin-heterozygous (Eng^+/−) mice show persisting fibroblasts 12 days after wounding, which could lead to a fibrotic scar. Endoglin haploinsufficiency results in increased proliferation and migration of primary cultured murine dermal fibroblasts (MDFs). Moreover, Eng^+/− MDF have diminished responses to apoptotic signals compared with control cells. Altogether, these modifications could explain the augmented presence of fibroblasts in Eng^+/− mice wounds. We demonstrate that endoglin expression regulates Akt phosphorylation and that PI3K inhibition abolishes the differences in proliferation between endoglin haploinsufficient and control cells. Finally, persistent fibroblasts in Eng^+/− mice wound co-localize with a greater degree of Akt phosphorylation. Thus, endoglin haploinsufficiency seems to promote fibroblast accumulation during wound healing through the activation of the PI3K/Akt pathway. These studies open new non-Smad signaling pathway for endoglin regulating fibroblast cell function during wound healing, as new therapeutic opportunities for the treatment of fibrotic wounds.     

Exosomes derived from human amniotic epithelial cells accelerate wound healing and inhibit scar formation

Wound healing is a highly orchestrated physiological process consisting of a complex events, and scarless wound healing is highly desired for the development and application in clinical medicine. Recently, we have demonstrated that human amniotic epithelial cells (hAECs) promoted wound healing and inhibited scar formation through a paracrine mechanism. However, exosomes (Exo) are one of the most important paracrine factors. Whether exosomes derived from human amniotic epithelial cells (hAECs-Exo) have positive effects on scarless wound healing have not been reported yet. In this study, we examined the role of hAECs-Exo on wound healing in a rat model. We found that hAECs, which exhibit characteristics of both embryonic and mesenchymal stem cells, have the potential to differentiate into all three germ layers. hAECs-Exo ranged from 50 to 150 nm in diameter, and positive for exosomal markers CD9, CD63, CD81, Alix, TSG101 and HLA-G. Internalization of hAECs-Exo promoted the migration and proliferation of fibroblasts. Moreover, the deposition of extracellular matrix (ECM) were partly abolished by the treatment of high concentration of hAECs-Exo (100 μg/mL), which may be through stimulating the expression of matrix metalloproteinase-1 (MMP-1). In vivo animal experiments showed that hAECs-Exo improved the skin wound healing with well-organized collagen fibers. Taken together, These findings represent that hAECs-Exo can be used as a novel hope in cell-free therapy for scarless wound healing.     

Conditioned media from human umbilical cord blood-derived mesenchymal stem cells stimulate rejuvenation function in human skin

Developing treatments that inhibit skin aging is an important research project. Rejuvenation, which focuses on prevention of skin aging, is one of the major issues. Recent studies suggested that mesenchymal stem cells (MSCs) secrete many cytokines, which are important in wound healing. In this study, we investigated the effect of human umbilical cord blood-derived mesenchymal stem cells conditioned media (USC-CM) in cutaneous wound healing and collagen synthesis. We found that USC-CM has many useful growth factors associated with skin rejuvenation, such as Epithelial Growth Factor (EGF), basic Fibroblast Growth Factor (bFGF), Platelet Derived Growth Factor (PDGF), Hepatocyte Growth Factor (HGF), Collagen type 1, and especially, one of the rejuvenation factors, the growth differentiation factor-11 (GDF-11). Our in vitro results showed that USC-CM stimulate growth and extracellular matrix (ECM) production of Human Dermal Fibroblasts (HDFs) compared to those of other MSCs conditioned media (CM) from different origins. Moreover, we evaluated the roles of GDF-11. The results showed that GDF-11 accelerates growth, migration and ECM production of HDFs. Our In vivo results showed that topical treatment of USC-CM showed anti-wrinkle effect and significantly increased dermal density in women. In conclusion, USC-CM has various useful growth factors including GDF-11 that can stimulate skin rejuvenation by increasing growth and ECM production of HDFs.     

Mesenchymal stem cell-conditioned medium accelerates skin wound healing: An in vitro study of fibroblast and keratinocyte scratch assays

We have used in vitro scratch assays to examine the relative contribution of dermal fibroblasts and keratinocytes in the wound repair process and to test the influence of mesenchymal stem cell (MSC) secreted factors on both skin cell types. Scratch assays were established using single cell and co-cultures of L929 fibroblasts and HaCaT keratinocytes, with wound closure monitored via time-lapse microscopy. Both in serum supplemented and serum free conditions, wound closure was faster in L929 fibroblast than HaCaT keratinocyte scratch assays, and in co-culture the L929 fibroblasts lead the way in closing the scratches. MSC-CM generated under serum free conditions significantly enhanced the wound closure rate of both skin cell types separately and in co-culture, whereas conditioned medium from L929 or HaCaT cultures had no significant effect. This enhancement of wound closure in the presence of MSC-CM was due to accelerated cell migration rather than increased cell proliferation. A number of wound healing mediators were identified in MSC-CM, including TGF-β1, the chemokines IL-6, IL-8, MCP-1 and RANTES, and collagen type I, fibronectin, SPARC and IGFBP-7. This study suggests that the trophic activity of MSC may play a role in skin wound closure by affecting both dermal fibroblast and keratinocyte migration, along with a contribution to the formation of extracellular matrix.     

Soft tissue fibroblasts from well healing and chronic human wounds show different rates of myofibroblasts in vitro

Due to an increasing life expectancy in western countries, chronic wound treatment will be an emerging challenge in the next decades. Because therapies are improving slowly appropriate diagnostic tools enabling the early prediction of the healing success remain to be developed. We used a well-established in vitro assay in combination with the analysis of 27 cytokines to discriminate between fibroblasts from chronic (n = 6) and well healing (n = 8) human wounds. Proliferation and migration of the cells as well as their response to hypoxia and their behaviour in co-culture with microvascular endothelial cells were analyzed. Myofibroblast differentiation, a time-limited essential process of regular wound healing, was also quantified. Besides weaker proliferation and migration significantly higher rates of myofibroblasts were detected in chronic wounds. With respect to the cytokine release, there was a clear trend within the group of chronic wound fibroblasts, which were releasing interferon-γ, monocyte chemotactic protein-1, granulocyte–macrophage colony stimulating factor and basic fibroblast growth factor in higher amounts than fibroblasts from healing wounds. Although the overall response of both groups of fibroblasts to hypoxia and to the contact with endothelial cells was similar, especially chronic wound fibroblasts seemed to benefit from the endothelial interaction during hypoxia and displayed better migration characteristics. The study shows (1) that the assay can identify specific features of fibroblasts derived from different human wounds and (2) that wound fibroblasts are varying in their response to the chosen parameters. Thus, current therapeutic approaches and individual healing prediction might benefit from this assay.     

Role of vitronectin and fibronectin receptors in oral mucosal and dermal myofibroblast differentiation

Background information. The activation of fibroblasts into myofibroblasts is a crucial event in healing that is linked to remodelling and scar formation, therefore we determined whether regulation of myofibroblast differentiation via integrins might affect wound healing responses in populations of patient‐matched HOFs (human oral fibroblasts) compared with HDFs (human dermal fibroblasts). Results. Both the HOF and HDF cell types underwent TGF‐β1 (transforming growth factor‐β1)‐induced myofibroblastic differentiation [upregulation of the expression of α‐sma (α‐smooth muscle actin)], although analysis of unstimulated cells indicated that HOFs contained higher basal levels of α‐sma than HDFs (P<0.05). Functional blocking antibodies against the integrin subunits α5 (fibronectin) or αv (vitronectin) were used to determine whether the effects of TGF‐β1 were regulated via integrin signalling pathways. α‐sma expression in both HOFs and HDFs was down‐regulated by antibodies against both α5 and αv. Functionally, TGF‐β1 inhibited cell migration in an in vitro wound model and increased the contraction of collagen gels. Greater contraction was evident for HOFs compared with HDFs, both with and without stimulation by TGF‐β1 (P<0.05). When TGF‐β1‐stimulated cells were incubated with blocking antibodies against α5 and αv, gel contraction was decreased to that of non‐stimulated cells; however, blocking αv or α5 could not restore cellular migration in both HOFs and HDFs. Conclusions. Despite intrinsic differences in their basal state, the cellular events associated with TGF‐β1‐induced myofibroblastic differentiation are common to both HOFs and HDFs, and appear to require differential integrin usage; up‐regulation of α‐sma expression and increases in collagen gel contraction are vitronectin‐ and fibronectin‐receptor‐dependent processes, whereas wound re‐population is not.     

Function of Chemokine (CXC Motif) Ligand 12 in Periodontal Ligament Fibroblasts

The periodontal ligament (PDL) is one of the connective tissues located between the tooth and bone. It is characterized by rapid turnover. Periodontal ligament fibroblasts (PDLFs) play major roles in the rapid turnover of the PDL. Microarray analysis of human PDLFs (HPDLFs) and human dermal fibroblasts (HDFs) demonstrated markedly high expression of chemokine (CXC motif) ligand 12 (CXCL12) in the HPDLFs. CXCL12 plays an important role in the migration of mesenchymal stem cells (MSCs). The function of CXCL12 in the periodontal ligament was investigated in HPDLFs. Expression of CXCL12 in HPDLFs and HDFs was examined by RT-PCR, qRT-PCR and ELISA. Chemotactic ability of CXCL12 was evaluated in both PDLFs and HDFs by migration assay of MSCs. CXCL12 was also immunohistochemically examined in the PDL in vivo. Expression of CXCL12 in the HPDLFs was much higher than that in HDFs in vitro. Migration assay demonstrated that the number of migrated MSCs by HPDLFs was significantly higher than that by HDFs. In addition, the migrated MSCs also expressed CXCL12 and several genes that are familiar to fibroblasts. CXCL12 was immunohistochemically localized in the fibroblasts in the PDL of rat molars. The results suggest that PDLFs synthesize and secrete CXCL12 protein and that CXCL12 induces migration of MSCs in the PDL in order to maintain rapid turnover of the PDL.     

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.     

Adipose tissue extract shows potential for wound healing: in vitro proliferation and migration of cell types contributing to wound healing in the presence of adipose tissue preparation and platelet rich plasma

Growth factors are the key elements in wound healing signaling for cell migration, differentiation and proliferation. Platelet-rich plasma (PRP), one of the most studied sources of growth factors, has demonstrated to promote wound healing in vitro and in vivo. Adipose tissue is an alternative source of growth factors. Through a simple lipoaspirate method, adipose derived growth factor-rich preparation (adipose tissue extract; ATE) can be obtained. The authors set out to compare the effects of these two growth factor sources in cell proliferation and migration (scratch) assays of keratinocyte, fibroblast, endothelial and adipose derived stem cells. Growth factors involved in wound healing were measured: keratinocyte growth factor, epidermal growth factor, insulin-like growth factor, interleukin 6, platelet-derived growth factor beta, tumor necrosis factor alfa, transforming growth factor beta and vascular endothelial growth factor. PRP showed higher growth factor concentrations, except for keratinocyte growth factor, that was present in adipose tissue in greater quantities. This was reflected in vitro, where ATE significantly induced proliferation of keratinocytes at day 6 (p < 0.001), compared to plasma and control. Similarly, ATE-treated fibroblast and adipose stem cell cultures showed accelerated migration in scratch assays. Moreover, both sources showed accelerated keratinocyte migration. Adipose tissue preparation has an inductive effect in wound healing by proliferation and migration of cells involved in wound closure. Adipose tissue preparation appears to offer the distinct advantage of containing the adequate quantities of growth factors that induce cell activation, proliferation and migration, particularly in the early phase of wound healing.