In vitro human cord blood platelet lysate characterisation with potential application in wound healing

Platelets contain abundant growth factors and cytokines that have a positive influence on the migration and proliferation of different cell types by modulating its physiopathological processes. As it is known that human umbilical cord blood platelet lysate (UCB‐PL) contains a supraphysiological concentration of growth factors, in the present study, we investigated its effectiveness in wound‐healing processes. Human UCB‐PL was obtained by the freeze/thaw of platelet concentrate (1.1 × 10⁹ platelets/L), and its effect was evaluated on human or mouse endothelial cells, monocytes, fibroblasts, and keratinocytes in different concentrations. Human UCB‐PL was observed to have high levels of pro‐angiogenic growth factor than peripheral blood platelet‐rich plasma. Among the cell lines, different concentrations of human UCB‐PL were necessary to influence their viability and proliferation. For L929 cells, 5% of total volume was necessary, while for human umbilical vein endothelial cell, it was 10%. Cell migration on monocytes was increased with respect to the positive control, and scratch closure on keratinocytes was increased with respect to serum‐free medium with only 10% of human UCB‐PL. We concluded that the human UCB‐PL may be useful to produce a large amount of standard platelet concentrates sufficient for several clinical‐scale expansions avoiding inter‐individual variability, which can also be used as a functional tool for clinical regenerative application for wound healing.     

Application of platelet‐rich gel to enhance healing of transmetatarsal amputations in diabetic dysvascular patients

Transmetatarsal amputation (TMA) represents an effective surgical procedure used to treat several clinical conditions such as forefoot infection, gangrene and chronic ulceration in diabetic patients. TMA permits walking without the need for prosthesis, but nevertheless is burdened with a high complications rate. The aim of this study was to evaluate the possibility to use platelet gel (PG) as an adjuvant therapy when performing TMA procedure in diabetic patients. In a 6‐year period, 26 diabetic patients had undergone TMA procedure followed by autologous PG applications (group A) and 32 patients had undergone TMA as sole procedure (group B). After TMA procedure, the treatment is based on outpatient management and consists of a weekly platelet‐rich plasma gel application on the surgical wound for 1 month in group A and on clinical evaluation only for group B. For group A, healing rate was of 96·15% and one patient (3·84%) presented wound dehiscence, and no postoperative wound infections occurred. For group B, healing rate was of 59·37%; severe infection of the stump prompted to the proximal amputations in 40·62% of patients during the follow‐up period. PG application may be an effective adjuvant treatment to improve wound healing in diabetic dysvascular patients.     

Expired liquid preserved platelet releasates retain proliferative activity

BACKGROUND: Donated platelets for clinical use currently have a shelf life of 5 days as the result of possible bacterial contamination and loss of hemostatic function. Platelet releasates contain multiple growth factors that have been shown to accelerate wound healing. We sought to demonstrate that although expired platelets can no longer sustain hemostasis, they serve a longer term role as a reservoir of growth factors that could be harnessed in wound healing applications. MATERIALS AND METHODS: Liquid preserved human platelets were activated from 1 to 21 days after collection using zeolite and were then analyzed for their ability to stimulate human fibroblast proliferation, which is an in vitro serogate of growth factor activity and wound healing potential. Total protein content, the concentration of platelet-derived growth factor (PDGF) and transforming growth factor-beta were also measured. RESULTS: Activated liquid preserved platelet releasates significantly stimulated fibroblast proliferation. Twenty-one-day-old platelets were as stimulatory as 2-day-old platelets. Total protein concentration, PDGF, and transforming growth factor-beta concentrations remained constant throughout the 21-day course. Western blot analysis using an antibody against human PDGF revealed minimal protein degradation over time. CONCLUSIONS: These data demonstrate that although the role of platelets as hemostatic agents degrades rapidly with time, platelets' ability to serve as a reservoir for growth factors remains intact for at least 3 weeks. These growth factors could be collected, stored, and used as a topical agent to promote healing of chronic and recalcitrant wounds.     

Bioactivity and stability of endogenous fibrogenic factors in platelet-rich fibrin

Platelet‐rich fibrin (PRF^®) is an autologous fibrin sealant (FS) enriched with a platelet concentrate (>1,000,000 platelets/μL) produced by the automated Vivostat^® system and used to enhance wound healing. The effects of PRF were compared with supernatant from thrombin‐activated platelet concentrate, recombinant human platelet‐derived growth factor (rhPDGF) isoforms, and a homologous FS in cultured normal human dermal fibroblasts. Also, the release of selected endogenous growth factors from PRF and their stability against proteolytic degradation were studied. The proliferative effect of PRF exceeded that of FS and rhPDGF‐BB, although it was lower than thrombin‐activated platelet concentrate possibly due to sustained growth factor release from platelets in PRF. Anti‐PDGF antibody blocked the mitogenic effect of rhPDGF‐BB but not that of PRF in growth‐arrested fibroblasts. PRF promoted secretion of carboxyterminal propeptide of type I collagen into conditioned medium while rhPDGF‐AB had no significant effect on collagen biosynthesis. Limited proteolysis of PDGF‐AB and no proteolysis of transforming growth factor‐β1 (TGF‐β1) in PRF were observed with trypsin treatment, whereas rhPDGF‐AB and rhTGF‐β1 in bovine serum albumin, matching the total protein concentration of PRF, were almost completely degraded after 24 hours at 37 °C. To conclude, PRF provides sustained release and protection against proteolytic degradation of endogenous fibrogenic factors important for wound healing.     

Potential use of blood bank platelet concentrates to accelerate wound healing of diabetic ulcers

Many clinical trials have shown the effectiveness of platelet releasates on diabetic wound healing, but large volumes of blood must be aspirated from patients and a platelet separator is required. This study was undertaken to investigate the potential of blood bank platelet concentrate (BBPC) for accelerating diabetic wound healing. Platelet-derived growth factor-BB (PDGF-BB) contents in BBPC were determined by enzyme-linked immunosorbent assay in vitro, and the in vivo study involved comparing extents of wound healing in BBPC-treated and control groups using diabetic mouse wound models. In the in vitro study, 5.2 +/- 1.2 pg of PDGF-BB was found to be released by 1 million platelets in fresh BBPC, and adding thrombin to BBPC significantly increased the levels of PDGF-BB released. Our in vivo study in diabetic mice revealed that BBPC treatment greatly accelerated wound healing. Our results suggest that BBPC has potential to accelerate the healing of diabetic ulcers.     

Trehalose lyophilized platelets for wound healing

Fresh platelet preparations are utilized to treat a wide variety of wounds, although storage limitations and mixed results have hampered their clinical use. We hypothesized that concentrated lyophilized and reconstituted platelet preparations, preserved with trehalose, maintain and possibly enhance fresh platelets' ability to improve wound healing. We studied the ability of a single dose of trehalose lyophilized and reconstituted platelets to enhance wound healing when topically applied on full-thickness wounds in the genetically diabetic mouse. We compared these results with the application of multiple doses of fresh platelet preparations and trehalose lyophilized and reconstituted platelets as well as multiple doses of vascular endothelial growth factor (VEGF) and wounds left untreated. Trehalose lyophilized and reconstituted platelets, in single and multiple applications, multiple applications of fresh platelets and multiple applications of VEGF increased granulation tissue deposition, vascularity, and proliferation when compared with untreated wounds, as assessed by histology and immunohistochemistry. Wounds treated with multiple doses of VEGF and a single dose of freeze-dried platelets reached 90% closure faster than wounds left untreated. A single administration of trehalose lyophilized and reconstituted platelet preparations enhanced diabetic wound healing, therefore representing a promising strategy for the treatment of nonhealing wounds.     

No positive effect of autologous platelet gel after total knee arthroplasty

Background and purpose Activated platelets release a cocktail of growth factors, some of which are thought to stimulate repair. We investigated whether the use of autologous platelet gel (PG) in total knee arthroplasty (TKA) would improve wound healing and knee function, and reduce blood loss and the use of analgesics.

Patients and methods 102 patients undergoing TKA were randomly assigned to a PG group (n = 50) or to a control (C) group (n = 52). The primary analysis was based on 73 participants (PG: 32; C: 41) with comparison of postoperative wound scores, VAS, WOMAC, knee function, use of analgesics, and the pre- and postoperative hemoglobin values after a follow-up of 3 months. 29 participants were excluded due to insufficient data.

Results The characteristics of the protocol-compliant patients were similar to those of the patients who were excluded. Analysis was per protocol and focused on the remaining 73 patients. At baseline and after 3 months of follow-up, there were no statistically significant differences between both groups regarding age, height, weight, sex, side of operation, platelet count, hemoglobin values, severity of complaints (WOMAC), and level of pain.

Interpretation In our patients undergoing TKA, application of PG to the wound site did not promote wound healing. Also, we found that PG had no effect on pain, knee function, or hemoglobin values.     

No positive effect of autologous platelet gel after total knee arthroplasty: A double-blind randomized controlled trial: 102 patients with a 3-month follow-up

Background and purpose Activated platelets release a cocktail of growth factors, some of which are thought to stimulate repair. We investigated whether the use of autologous platelet gel (PG) in total knee arthroplasty (TKA) would improve wound healing and knee function, and reduce blood loss and the use of analgesics.Patients and methods 102 patients undergoing TKA were randomly assigned to a PG group (n = 50) or to a control (C) group (n = 52). The primary analysis was based on 73 participants (PG: 32; C: 41) with comparison of postoperative wound scores, VAS, WOMAC, knee function, use of analgesics, and the pre- and postoperative hemoglobin values after a follow-up of 3 months. 29 participants were excluded due to insufficient data.Results The characteristics of the protocol-compliant patients were similar to those of the patients who were excluded. Analysis was per protocol and focused on the remaining 73 patients. At baseline and after 3 months of follow-up, there were no statistically significant differences between both groups regarding age, height, weight, sex, side of operation, platelet count, hemoglobin values, severity of complaints (WOMAC), and level of pain.Interpretation In our patients undergoing TKA, application of PG to the wound site did not promote wound healing. Also, we found that PG had no effect on pain, knee function, or hemoglobin values.     

Development of a PHMB hydrogel‐modified wound scaffold dressing with antibacterial activity

Current wound scaffold dressing constructs can facilitate wound healing but do not exhibit antibacterial activity, resulting in high infection rates. We aimed to endow wound scaffold dressing with anti‐infective ability by polyhexamethylenebiguanide (PHMB). We prepared PHMB hydrogel at varying concentrations (0.25%, 0.5%, 1%, 2%) and assessed release and cytotoxicity. PHMB hydrogel was added to the wound scaffold dressing to generate a PHMB hydrogel‐modified wound scaffold dressing. Wound healing and infection prevention were evaluated using a full‐thickness skin defect model in rats. In vitro, the hydrogel PHMB release time positively correlated with PHMB concentration, with 1% allowing sufficiently long release time to encompass the high‐incidence period (3‐5 days) of infection following wound scaffold dressing implantation. Implantation of 1% PHMB hydrogel into the skin did not cause adverse responses. in vitro cytotoxicity assays showed the PHMB hydrogel‐modified wound scaffold dressing did not significantly affect proliferation of fibroblasts or vascular endothelial cells, 99.90% vs 99.84% for fibroblasts and 100.21% vs 99.28% for vascular endothelial cells at 21 days. Transplantation of PHMB hydrogel‐modified wound scaffold dressing/unmodified wound scaffold dressing on the non‐infected wounds of rats yielded no significant difference in relative vascularization rate, 47.40 vs 50.87 per view at 21 days, whereas bacterial content of the wound tissue in the PHMB hydrogel‐modified wound scaffold dressing group was significantly lower than the unmodified wound scaffold dressing group, (1.80 ± 0.35) × 10³ vs (9.34 ± 0.45) × 10³ at 14 days. Prevalence of persistent wound infection in the rats receiving PHMB hydrogel‐modified wound scaffold dressing transplantation onto infected wounds was significantly lower than the unmodified wound scaffold dressing group, 30% vs 100%. PHMB hydrogel‐modified wound scaffold dressing exhibited suitable antibacterial ability, and its biological activity did not significantly differ from that of the unmodified wound scaffold dressing, thereby allowing it to effectively prevent infection following wound scaffold dressing implantation.     

Comparison of human umbilical cord blood‐derived mesenchymal stem cells with healthy fibroblasts on wound‐healing activity of diabetic fibroblasts

Various types of skin substitutes composed of fibroblasts and/or keratinocytes have been used for the treatment of diabetic ulcers. However, the effects have generally not been very dramatic. Recently, human umbilical cord blood‐derived mesenchymal stromal cells (hUCB‐MSCs) have been commercialised for cartilage repair as a first cell therapy product using allogeneic stem cells. In a previous pilot study, we reported that hUCB‐MSCs have a superior wound‐healing capability compared with fibroblasts. The present study was designed to compare the treatment effect of hUCB‐MSCs with that of fibroblasts on the diabetic wound healing in vitro. Diabetic fibroblasts were cocultured with healthy fibroblasts or hUCB‐MSCs. Five groups were evaluated: group I, diabetic fibroblasts without coculture; groups II and III, diabetic fibroblasts cocultured with healthy fibroblasts or hUCB‐MSCs; and groups IV and V, no cell cocultured with healthy fibroblasts or hUCB‐MSCs. After a 3‐day incubation, cell proliferation, collagen synthesis levels and glycosaminoglycan levels, which are the major contributing factors in wound healing, were measured. As a result, a hUCB‐MSC‐treated group showed higher cell proliferation, collagen synthesis and glycosaminoglycan level than a fibroblast‐treated group. In particular, there were significant statistical differences in collagen synthesis and glycosaminoglycan levels (P = 0·029 and P = 0·019, respectively). In conclusion, these results demonstrate that hUCB‐MSCs may have a superior effect to fibroblasts in stimulating diabetic wound healing.     

Platelets, but not erythrocytes, significantly affect cytokine release and scaffold contraction in a provisional scaffold model

Platelets and erythrocytes are major components of wound provisional scaffolding. In this study, we hypothesized that the concentration of platelets and erythrocytes would significantly affect fibroblast‐mediated contraction of three‐dimensional scaffolds or the release of cytokines from the scaffold. To test this hypothesis, human anterior cruciate ligament fibroblasts were cultured in one of four scaffolds: a collagen matrix, a collagen‐fibrin matrix containing the same concentration of platelets as whole blood, a collagen‐fibrin matrix containing a high platelet concentration, and a collagen–fibrin matrix containing a high platelet concentration and red blood cells. Cytokine release from the four groups of gels and gel contraction were measured over a 10‐day period. The results of these assays supported greater cytokine release, fibroblast proliferation, and gel contraction in scaffolds with higher platelet concentration. In contrast, the addition of erythrocytes did not significantly stimulate or suppress scaffold contraction or growth factor release from the provisional scaffolds. We concluded that while platelet concentration can significantly impact cytokine release and scaffold retraction in a provisional scaffold, the inclusion of erythrocytes does not have a significant effect on these same behaviors. Therefore, while platelets may be an important regulator of repair processes after injury, it is less likely that erythrocytes have a similar function.     

Increasing platelet concentration in platelet‐rich plasma inhibits anterior cruciate ligament cell function in three‐dimensional culture

Tissue engineering is one new strategy being developed to treat ACL ruptures. One such approach is bio‐enhanced ACL repair, where a suture repair is supplemented with a bio‐active scaffold containing platelets. However, the optimal concentration of platelets to stimulate ACL healing is not known. We hypothesized that increasing platelet concentrations in the scaffold would enhance critical cell behaviors. Porcine ACL fibroblasts were obtained from explant culture and suspended in platelet poor plasma (PPP), 1× platelet‐rich plasma (PRP), 3× PRP, 5× PRP, or phosphate buffered saline (PBS). The cell suspensions were cultured in a 3D collagen scaffold. Cellular metabolism (MTT assay), apoptosis (TUNEL assay), and gene expression for type I and type III collagen were measured. 1× PRP significantly outperformed 5× PRP in all parameters studied: Type I and III collagen gene expression, apoptosis prevention, and cell metabolism stimulation. ACL fibroblasts cultured with 1× PRP had the highest type I and type III collagen gene expression. 1× PRP and PPP groups had the highest cell metabolism and lowest apoptosis rates. Concentration of platelets had significant effects on the behavior of ACL fibroblasts; thus, it is an important parameter that should be specified in clinical or basic science studies. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:291–295, 2014.     

Surfactants: Role in biofilm management and cellular behaviour

Appropriate and effective wound cleaning represents an important process that is necessary for preparing the wound for improved wound healing and for helping to dislodge biofilms. Wound cleaning is of paramount importance to wound bed preparation for helping to enhance wound healing. Surfactant applications in wound care may represent an important area in the cleaning continuum. However, understanding of the role and significance of surfactants in wound cleansing, biofilm prevention and control, and enhancing cellular viability and proliferation is currently lacking. Despite this, some recent evidence on poloxamer‐based surfactants where the surfactants are present in high concentration have been shown to have an important role to play in biofilm management; matrix metalloproteinase modulation; reducing inflammation; and enhancing cellular proliferation, behaviour, and viability. Consequently, this review aims to discuss the role, mode of action, and clinical significance of the use of medically accepted surfactants, with a focus on concentrated poloxamer‐based surfactants, to wound healing but, more specifically, the role they may play in biofilm management and effects on cellular repair.     

Mesenchymal stem cell‐conditioned medium accelerates wound healing with fewer scars

Mesenchymal stem cells (MSCs) derived from umbilical cord s (UC‐MSCs) have been shown to enhance cutaneous wound healing by means of the paracrine activity. Fibroblasts are the primary cells involved in wound repair. The paracrine effects of UC‐MSCs on dermal fibroblasts have not been fully explored in vitro or in vivo. Dermal fibroblasts were treated with conditioned media from UC‐MSCs (UC‐MSC‐CM). In this model, UC‐MSC‐CM increased the proliferation and migration of dermal fibroblasts. Moreover, adult dermal fibroblasts transitioned into a phenotype with a low myofibroblast formation capacity, a decreased ratio of transforming growth factor‐β1,3 (TGF‐β1/3) and an increased ratio of matrix metalloproteinase/tissue inhibitor of metalloproteinases (MMP/TIMP). Additionally, UC‐MSC‐CM‐treated wounds showed accelerated healing with fewer scars compared with control groups. These observations suggest that UC‐MSC‐CM may be a feasible strategy to promote cutaneous repair and a potential means to realise scarless healing.     

Characteristics of an autologous leukocyte and platelet‐rich fibrin patch intended for the treatment of recalcitrant wounds

We have investigated the physical, biochemical, and cellular properties of an autologous leukocyte and platelet‐rich fibrin patch. This was generated in an automated device from a sample of a patient's blood at the point of care. Using microscopy, cell counting, enzyme‐linked immunosorbent assay, antibody arrays, and cell culture assays, we show that the patch is a three‐layered membrane comprising a fibrin sheet, a layer of platelets, and a layer of leukocytes. Mean recovery of platelets from the donated blood was 98% (±95%CI 0.8%). Mean levels of platelet‐derived growth factor AB, human transforming growth factor beta 1, and vascular endothelial growth factor extracted from the patch were determined as 127 ng (±95% CI 20), 92 ng (±95%CI 17), and 1.35 ng (±95%CI 0.37), respectively. We showed a continued release of PDGF‐AB over several days, the rate of which was increased by the addition of chronic wound fluid. By comparison with traditional platelet‐rich plasma, differences in immune components were found. The relevance of these findings was assessed by showing a mitogenic and migratory effect on cultured human dermal fibroblasts. Further, we showed that fibrocytes, a cell type important for acute wound healing, could be grown from the patch. The relevance of these findings in relation to the use of the patch for treating recalcitrant wounds is discussed.     

Acidic preparations of platelet concentrates release bone morphogenetic protein‐2

Background and purpose?Growth factors released from platelets have potent effects on fracture and wound healing. The acidic tide of wound healing, i.e. the pH within wounds and fractures, changes from acidic pH to neutral and alkaline pH as the healing process progresses. We investigated the influence of pH on lysed platelet concentrates regarding the release of growth factors.

Material and methods?Platelet concentrates free of leukocyte components were lysed and incubated in buffers with pH between 4.3 and 8.6. Bone morphogenetic protein-2 (BMP-2), platelet‐derived growth factor (PDGF), transforming growth factor-β (TGF-β), and vascular endothelial growth factor (VEGF) were measured by quantitative enzyme‐linked immunosorbent assays.

Results?PDGF, TGF-β, and VEGF were present in all platelet preparations but the levels varied in a pH‐dependent fashion. BMP-2 was only detected in the most acidic preparation (pH 4.3), which is interesting since BMP-2 has been reported to be an endogenous mediator of fracture repair and to be responsible for the initiation of fracture healing.

Interpretation?Our findings indicate that platelets release substantial amounts of BMP-2 only under conditions of low pH, the milieu associated with the critical initial stage of fracture healing.     

Acceleration of cutaneous wound healing by brassinosteroids

Brassinosteroids are plant growth hormones involved in cell growth, division, and differentiation. Their effects in animals are largely unknown, although recent studies showed that the anabolic properties of brassinosteroids are possibly mediated through the phosphoinositide 3‐kinase/protein kinase B signaling pathway. Here, we examined biological activity of homobrassinolide (HB) and its synthetic analogues in in vitro proliferation and migration assays in murine fibroblast and primary keratinocyte cell culture. HB stimulated fibroblast proliferation and migration and weakly induced keratinocyte proliferation in vitro. The effects of topical HB administration on progression of wound closure were further tested in the mouse model of cutaneous wound healing. C57BL/6J mice were given a full‐thickness dermal wound, and the rate of wound closure was assessed daily for 10 days, with adenosine receptor agonist CGS‐21680 as a positive control. Topical application of brassinosteroid significantly reduced wound size and accelerated wound healing in treated animals. mRNA levels of transforming growth factor beta and intercellular adhesion molecule 1 were significantly lower, while tumor necrosis factor alpha was nearly suppressed in the wounds from treated mice. Our data suggest that topical application of brassinosteroids accelerates wound healing by positively modulating inflammatory and reepithelialization phases of the wound repair process, in part by enhancing Akt signaling in the skin at the edges of the wound and enhancing migration of fibroblasts in the wounded area. Targeting this signaling pathway with brassinosteroids may represent a promising approach to the therapy of delayed wound healing.     

Extracellular matrix/stromal vascular fraction gel conditioned medium accelerates wound healing in a murine model

Conditioned medium (CM) is a new treatment modality in regenerative medicine and has shown a successful outcome in wound healing. We recently introduced extracellular matrix/stromal vascular fraction gel (ECM/SVF‐gel), an adipose‐derived stem cell and adipose native extracellular matrix‐enriched product for cytotherapy. This study aimed to evaluate the effect of CM from ECM/SVF‐gel (Gel‐CM) on wound healing compared with the conventional CM from adipose tissue (Adi‐CM) and stem cell (SVF‐CM). In vitro wound healing effect of three CMs on keratinocytes and fibroblasts was evaluated in terms of proliferation property, migratory property, and extracellular matrix production. In vivo, two full‐thickness wounds were created on the back of each mice. The wounds were randomly divided to receive Gel‐CM, Adi‐CM, SVF‐CM, and PBS injection. Histologic observations and collagen content of wound skin were made. Growth factors concentration in three CMs was further quantified. In vitro, Gel‐CM promoted the proliferation and migration of keratinocytes and fibroblasts and enhanced collagen I synthesis in fibroblasts compared to Adi‐CM and SVF‐CM. In vivo, wound closure was faster, and dermal and epidermal regeneration was improved in the Gel‐CM‐treated mice compared to that in Adi‐CM and SVF‐CM‐treated mice. Moreover, The growth factors concentration (i.e., vascular endothelial growth factor, basic fibroblast growth factor, hepatocyte growth factor, and transforming growth factor‐β) in Gel‐CM were significantly higher than those in Adi‐CM and SVF‐CM. Gel‐CM generated under serum free conditions significantly enhanced wound healing effect compared to Adi‐CM and SVF‐CM by accelerating cell proliferation, migration, and production of ECM. This improved trophic effect may be attributed to the higher growth factors concentration in Gel‐CM. Gel‐CM shows potential as a novel and promising alternative to skin wound healing treatment. But limitations include the safety and immunogenicity studies of Gel‐CM still remain to be clearly clarified and more data on mechanism study are needed.     

Pivotal role of ATP in macrophages fast tracking wound repair and regeneration

Chronic wounds occurring during aging or diabetes pose a significant burden to patients. The classical four‐phase wound healing process has a 3–6 day lag before granulation starts to appear and it requires an intermediate step of activation of resident fibroblasts during the remodeling phase for production of collagen. This brief communication discusses published articles that demonstrate how the entire wound healing process can be fast tracked by intracellular ATP delivery, which triggers a novel pathway where alternatively activated macrophages play absolutely critical and central roles. This novel pathway involves an increase in proinflammatory cytokines (TNF, IL‐1β, IL‐6) and a chemokine (MCP‐1) release. This is followed by activation of purinergic receptor (a family of plasma membrane receptors found in almost all mammalian cells), production of platelets and platelet microparticles, and activation of ATP‐dependent chromatin remodeling enzymes. The end result is a massive influx and in situ proliferation of macrophages, increases in vascular endothelial growth factors that promote neovascularization, and most prominently, the direct production of collagen.     

Effect of Panax ginseng extract on the activity of diabetic fibroblasts in vitro

Numerous studies have demonstrated the various medicinal properties of Panax ginseng, including angiogenic, immuno‐stimulating, antimicrobial, and anti‐inflammatory activities, which can be helpful in chronic wound healing. However, a direct role for P. ginseng in chronic wound healing has not been demonstrated. The present study was designed to evaluate the effects of P. ginseng extract on diabetic fibroblasts in vitro. Human diabetic fibroblasts were cultured in the presence of Ginsenoside Rb1 (G‐Rb1), the active component in P. ginseng (10 ng/mL), and untreated diabetic fibroblasts were used as controls. Cell proliferation, collagen synthesis, the production of various growth factors (basic fibroblast growth factor [bFGF]; vascular endothelial growth factor [VEGF]; and transforming growth factor‐β1 [TGF‐β1]), and the synthesis of matrix metalloproteinase 1 (MMP‐1) and tissue inhibitor of metalloproteinases 1 (TIMP‐1) were compared using enzyme‐linked immunosorbent assay and immunofluorescence staining. Compared with the control group, G‐Rb1‐treated fibroblasts showed significantly (P < 0.05) higher levels of cell proliferation, collagen synthesis, VEGF, TGF‐β1, and TIMP‐1. However, no significant differences in bFGF and MMP‐1 levels were observed between the two groups. These results suggest that P. ginseng treatment may stimulate the wound‐healing activity of diabetic fibroblasts in vitro.