Chronic Wound Fluid Research Articles

Cytokine stability in chronic wound fluid and its association to fibroblast proliferation.

Cytokines are commonly deregulated in venous leg ulcers. We have investigated cytokine stability by incubating sterile-filtered wound fluids from chronic venous leg ulcers in vitro. Incubation of wound fluids for 24 h at 37°C decreased IL-1β levels by 88% and TNF-α levels by 64%. IL-1β was degraded by serine proteinases and metalloproteinases while the mechanism for reduced TNF-α remains elusive. The levels of the other peptides did not change significantly (p > 0.05). Normal human dermal fibroblasts exposed to five of the six wound fluids showed increased proliferation with the length of prior incubation using an assay optimised for evaluation of wound fluid bioactivity. Exogenous IL-1β and TNF-α unexpectedly increased (p < 0.001) cell proliferation at concentrations that were measured in the wound fluids. In conclusion, the stability of the eight investigated cytokines in wound fluids differed and presumably the loss of detrimental factors, unlikely IL-1β or TNF-α, resulted in increased fibroblast proliferation.

Effect of placental mesenchymal stem cells on promoting the healing of chronic burn wounds

The treatment of chronic burn wounds is difficult in clinical practice. The ideal therapy is required to be continuously explored. Mesenchymal stem cells revolutionize the treatment of many diseases. The placental mesenchymal stem cells (PMSCs) have the characteristics of easy access, strong proliferation ability and multi-directional differentiation potential. The aim of this study was to investigate the potential of PMSCs in chronic burn wound healing. In this study, species of bacteria of 317 patients with chronic burn wounds have been analyzed. Samples of chronic burn wound fluid were collected from representative patients and then co-cultured with cells. In vitro studies showed that chronic burn wound fluid inhibited the proliferation of human keratinocytes and fibroblasts, while PMSCs can counteract the effects of burn wound fluid on inhibiting the proliferation and migration of human keratinocytes and fibroblasts. In addition, in vivo studies showed that a rat chronic burn wound model was successfully created. The expression of MMP-2, MMP-9, MDA, IL-6 and TNF-α in chronic burn wounds was significantly higher than that in acute burn wounds. Finally, the rat chronic burn wound model was used to verify that placental mesenchymal stem cell transplantation increased the wound healing rate, decreased the wound healing time, and promoted wound healing by increasing the thickness of epidermis and promoting the expression of P63 and CK10. The findings provide support for the hypothesis that PMSCs promote the repair of chronic burn wounds and key scientific data for the application of PMSCs as a new method for treating chronic burn wounds.

Nanoscopic and functional characterization of keratinocyte-originating exosomes in the wound fluid of non-diabetic and diabetic chronic wound patients

Exosomes, a class of extracellular vesicles of endocytic origin, play a critical role in paracrine signaling for successful cell-cell crosstalk in vivo. However, limitations in our current understanding of these circulating nanoparticles hinder efficient isolation, characterization, and downstream functional analysis of cell-specific exosomes. In this work, we sought to develop a method to isolate and characterize keratinocyte-originated exosomes (hExoκ) from human chronic wound fluid. Furthermore, we studied the significance of hExoκ in diabetic wounds. LC-MS-MS detection of KRT14 in hExoκ and subsequent validation by Vesiclepedia and Exocarta databases identified surface KRT14 as a reliable marker of hExoκ. dSTORM nanoimaging identified KRT14+ extracellular vesicles (EVκ) in human chronic wound fluid, 23% of which were of exosomal origin. An immunomagnetic two-step separation method using KRT14 and tetraspanin antibodies successfully isolated hExoκ from the heterogeneous pool of EV in chronic wound fluid of 15 non-diabetic and 22 diabetic patients. Isolated hExoκ (Ø 75–150 nm) were characterized per EV-track guidelines. dSTORM images, analyzed using online CODI platform followed by independent validation using Nanometrix, revealed hExoκ Ø as 80–145 nm. The abundance of hExoκ was low in diabetic wound fluids and negatively correlated with patient HbA1c levels. The hExoκ isolated from diabetic wound fluid showed a low abundance of small bp RNA (<200 bp). Raman spectroscopy underscored differences in surface lipids between non-diabetic and diabetic hExoκ. Uptake of hExoκ by monocyte-derived macrophages (MDM) was low for diabetics versus non-diabetics. Unlike hExoκ from non-diabetics, the addition of diabetic hExoκ to MDM polarized with LPS and INFγ resulted in sustained expression of iNOS and pro-inflammatory chemokines known to recruit macrophages (mϕ).This work provides maiden insight into the structure, composition, and function of hExoκ from chronic wound fluid thus providing a foundation for the study of exosomal malfunction under conditions of diabetic complications such as wound chronicity.

Impact of the chronic wound microenvironment and marine omega-3 fatty acids on skin cell regeneration processes.

Marine long-chain omega-3 polyunsaturated fatty acids (ω3 FA) are involved in numerous cell responses and therefore vital for the mammal organism. Because of the attribution of immunomodulatory effects, a favourable impact on the inflammatory response in chronic wounds and cells involved in wound healing can be suspected. In the experimental setup, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were investigated regarding their impact on metabolic activity, cell proliferation and migration of human keratinocytes (HaCaT) and newborn foreskin fibroblasts (CRL-2522). For simulation of the microenvironment of a chronic wound, human chronic wound fluid (CWF) was used in the experimental setup addressing the in vitro influence of DHA, EPA and CWF on regenerative processes. The results showed a significant increase in the metabolic activity of keratinocytes and fibroblasts after 72h treatment with DHA and EPA. In contrast, treatment with ω3 FA had no significant positive effect on skin cell proliferation. Both ω3 FA had no influence on in vitro wound closure. CWF demonstrated significantly adverse effects, which ω3 FA were unable to mitigate. It can be concluded that CWF exhibited the expected adverse effect on both skin cell types, especially inhibiting in vitro wound closure. ω3 FAs showed a slightly positive, yet rarely significant effect on human skin cells. Overall, the addition of DHA or EPA showed no relevant benefit for skin cells challenged with human CWF, merely in combination with DHA an initial significant increase in cell metabolism (fibroblasts) and cell proliferation (keratinocytes) could be observed.

Blind Comparative study between Silver nanoparticles dressings and Standard Moist Wound Dressings (SMWD) in management of diabetic foot ulcers

Abstract Background Diabetic foot ulcers (DFUs) are the main cause of hospitalization in diabetic patients and they are considered a major worldwide health problem. Thus, there is a need to evaluate various treatment modalities. In this study we will assess the clinical efficacy of Silver nanoparticles dressing vs Standard Moist Wound Dressing (SMWD) in management of diabetic foot ulcers. Objective To compare wound outcome, limb salvage, healing time of diabetes related foot ulcers and cost effectiveness in terms of duration of hospital stay between Silver nanotechnology dressings and Standard moist wound therapy (SMWT) in management of diabetic foot ulcers. Patients and Methods This is a prospective randomized controlled study involving 34 patients with active diabetic foot ulcers, in a high volume tertiary referral vascular center. They were divided into 2 groups: 17 patients (group A) were prescribed SMWD and the other 17 patients (group B) received Silver nanoparticles wound dressing. Results Our study correlates with the study conducted by K.Suhas et al. which had observed that Silver nanoparticles wound dressing was safe and effective treatment for complex diabetic foot wounds and could lead to higher proportion of healed wounds and faster healing rates. At the end of the study, group B promised a better outcome as compared to group A. Conclusion The role of Silver nanoparticles wound dressing in healing of diabetic foot ulcers has been proposed as a novel method of manipulating the chronic wound environment in a way that it reduces bacterial burden and chronic interstitial wound fluid, increases vascularity and cytokine expression and to an extent mechanically exploiting the viscoelasticity of peri wound tissues.

Conductive Gauze Based Electronic Sensor for Rapid Uric Acid Detection

Introduction Accurate real-time health monitoring with fabric-based biomedical devices is coming to the foreground with improvements in efficiency [1,2]. Cotton fabric-based wearable sensors are a soft and breathable substrate that provides comfort to patients. Flexibility, robustness and easy integration with skin or garments provide real-time updates of health issues [3]. Fast response time and low cost make the textile-based wearable sensors eye-catcher of the clinical market. Wearable sensors are used in various important clinical applications and the real status of a chronic wound is one of the critical issues. Wearable sensors for monitoring various wound parameters are reported using gauze [4,5]. These reported sensors suffered from mechanical and chemical stability with poor wireless connectivity [6,7]. In this study we have fabricated a textile woven, conformal, and conductive gauze based sensor that enables quantitative sensing of uric acid in chronic wound fluid. Sensor Design Cotton gauze was cleaned via acetone solution and kept for drying in the oven for 2 hrs. The cotton gauze surface was modified with graphene nano-platelet via dipping the treated gauze in graphene solution for 15 minutes followed by drying at room temperature. Graphene reducing agent basic L-cysteine solution was used to reduce oxidized graphene nano-platelets into neutral graphene-modified conductive gauze. Obtained conductive gauze is a flexible substrate. Screen printing technique is used for printing WE, RE and CE with silver ink (Fig. 1 A). The electrochemical response of uric acid on fabricated conductive gauze was evaluated via a multichannel electrochemical station (CHI-230B Potentiostat). Electrochemical Measurement Cyclic voltammetry was performed to evaluate the response of uric acid in a phosphate buffer saline solution (pH 7.4) over the fabricated conductive gauze. The well-defined redox peak at -0.38 V and 0.08 V in cyclic voltammogram confirms the selective and sensitive sensing of uric acid (Fig. 1 B). The linear response of scan rates and obtained current signal of uric acid confirms the diffusion-limited kinetics on conductive gauze. The diffusion-limited kinetics supports the mass transport mechanism on gauze (Fig. 1 C). This facilitates the ppm level selective sensing of uric acid and confirms the feasibility of fabricated gauze as a wound dressing. The uric acid response was evaluated for the same concentration (100 m M) on two conductive gauzes. Both gauzes were showing excellent reproducibility with RSD 1.2%. Furthermore, to evaluate the diffusion coefficient of uric acid on conductive gauze chonoamperometry measurements using different uric acid concentrations (50, 75, 100, 125 mM) in phosphate buffer saline (pH 7.4) were performed (Fig. 1 D). The mean diffusion coefficient of uric acid as per the Cottrell equation is 4.15×10−7 cm2 s-1. The result obtained from both electrochemical techniques, cyclic voltammetry and chronoamperometry confirm diffusion-limited kinetics on conductive gauze based flexible sensors. Conclusions The excellent electrochemical response of uric acid on metallic printed conductive gauze and reproducibility could open a new approach and flexible material for wound dressing. The mechanical stability in a thorough washing and flexibility test is under progress. Cheap, easily available, skin comfortable, disposable features and with the obtained electronic signal of fabricated conductive gauze, encourage us to design novel wound dressing, which can be integrated with human skin or garments and could serve as an assistant to monitor the status of chronic wounds.

Protease-Resistant Growth Factor Formulations for the Healing of Chronic Wounds.

Objective: Chronic wounds are long-term nonhealing wounds that are refractory to treatment. These wounds can present elevated protease levels, leading to rapid degradation of native and exogenously added growth factors. This work focused on developing a protease-resistant growth factor formulation for treatment of chronic wounds presented with high protease activity. Approach: This study developed protease-resistant growth factor formulations comprising elastin-like peptides (ELPs) fused with a known protease inhibitor peptide or growth factor. The ELP component of the fusion proteins allows assembly of heterogeneous nanoparticles (NPs) putting the inhibitor in close proximity to the growth factor to be protected. Results: We show successful preservation of growth factor activity in high human neutrophil elastase (HNE) environment and in human chronic wound fluid derived from patients. We further show that these NPs result in enhanced collagen remodeling and resolution of inflammation in a full thickness wound supplemented with HNE in genetically diabetic mice. Innovation: Development of heterogeneous NPs that put the protease inhibitor in close proximity of the growth factor. Moreover, the modular nature of the NPs allows for protection of multiple growth factors by the same inhibitor without changing the amino acid sequence of the growth factor. Conclusion: Our results indicate that the developed NPs hold tremendous promise in chronic wound healing therapy and may further help the translation of growth factor therapies to clinic. The customizable template for the NP design allows for multifaceted use across several fields in research and medicine.

Uncontrolled gelatin degradation in non-healing chronic wounds

To compare matrix metalloproteinase (MMP)-9 and the antiproteinase tissue inhibitor of metalloproteinases (TIMP)-1 in wound fluids and sera from patients with chronic non-healing or acute healing wounds. In addition, the functional consequences on MMP-9 activity and general gelatinase activity were assessed. In this observational study, samples were collected from patients with venous leg ulcers (VLUs), patients with type 2 diabetes with neuropathic foot ulcers (DFUs), and from another cohort of VLU patients with sterile split-thickness skin graft donor sites after autologous skin grafting, serving as healing control wounds. MMP-9 and TIMP-1 concentrations were determined by enzyme-linked immunosorbent assays. MMP-9 and gelatinase activities were determined in wound fluids in subsets of the patients. A total of 24 patients took part in the study. No significant differences in MMP-9 wound fluid levels were found among the three groups. TIMP-1 levels were markedly and significantly lower in the two chronic wound groups resulting in a severely unbalanced MMP-9/TIMP-1 ratio, especially notable in the VLU group and possibly in the elevated endogenous MMP-9 activity (p<0.01) compared with the acute wound fluids. At least 20% of the chronic wound fluids displayed atypical patterns on gelatin zymography and showed high general gelatinase activity that was not inhibited by either TIMP-1 or by a gelatinase inhibitor (AG3340). MMP-9 levels were higher in the sera of the patients with type 2 diabetes. We hypothesise that non-MMP proteinases contribute to matrix destruction in a significant number of chronic wounds. Blocking the excessive MMP-9 activity may be insufficient to normalise wound healing. The reasons and effects of the very low TIMP-1 levels in chronic wounds need further clarification.

Biological wound matrices with native dermis-like collagen efficiently modulate protease activity.

When the delicate balance between catabolic and anabolic processes is disturbed for any reason, the healing process can stall, resulting in chronic wounds. In chronic wound pathophysiology, proteolytic imbalance is implicated due to elevated protease levels mediating tissue damage. Hence, it is important to design appropriate wound treatments able to control and modulate protease activity directly at the host/biomaterial interface. Here, we investigate collagen-based wound dressings with the focus on their potential to adsorb and inactivate tissue proteases. We examined the effect of six collagen-based dressings on their ability to adsorb and inactivate different granulocyte proteases, plasmin, human neutrophil elastase (HLE), and matrix metalloproteases (MMP)-1, -2, -8, and -9, by an integrated approach including immunoelectron microscopy. We observed a reduction of the proteolytic activities of plasmin, HLE, and MMP-1, -2, -8, and -9, both on the biomaterial surface and in human chronic wound fluid. The most pronounced effect was observed in collagen-based dressings, with the highest content of native collagen networks resembling dermis structures. Our data suggest that this treatment strategy might be beneficial for the chronic wound environment, with the potential to promote improved wound healing.

Redox Profiling Reveals Clear Differences between Molecular Patterns of Wound Fluids from Acute and Chronic Wounds.

Wound healing is a complex multiphase process which can be hampered by many factors including impaired local circulation, hypoxia, infection, malnutrition, immunosuppression, and metabolic dysregulation in diabetes. Redox dysregulation is a common feature of many skin diseases demonstrated by virtually all cell types in the skin with overproduction of reactive oxygen and nitrogen species. The objective of this study was to characterize the redox environment in wound fluids and sera from patients suffering from chronic leg ulcers (n = 19) and acute wounds (bulla fluids from second degree burns; n = 11) with serum data also compared to those from healthy volunteers (n = 7). Significantly higher concentrations of TNF-α, interleukine-8, vascular endothelial growth factor, and lactate dehydrogenase (measure of cell damage) were found in fluids from chronic wounds compared to acute ones. The extent of protein carbonylation (measure of protein oxidation), lipid peroxidation, and tyrosine nitration (indicator of peroxynitrite production) was similar in acute and chronic wound fluids, while radical scavenging activity and glutathione (GSH) levels were elevated in chronic wound fluids compared to acute wounds. Sera were also assessed for the same set of parameters with no significant differences detected. Nitrotyrosine (the footprint of the potent oxidant peroxynitrite) and poly(ADP-ribose) (the product of the DNA damage sensor enzyme PARP-1) could be detected in wound biopsies. Our data identify multiple signs of redox stress in chronic wounds with notable differences. In chronic wounds, elevations in antioxidant levels/activities may indicate compensatory mechanisms against inflammation. The presence of nitrotyrosine and poly(ADP-ribose) in tissues from venous leg ulcers indicate peroxynitrite production and PARP activation in chronic wounds.

Acute and Chronic Wound Fluid Inversely Influence Wound Healing in an in-Vitro 3D Wound Model

If a wound progressively heals or the healing process is impaired is basically influenced by the surrounding milieu. This is reflected by the wound fluid. Its specific composition triggers the migration, proliferation and differentiation of dermal and epidermal cells which so far was not sufficiently examined in 2D cell culture models. The influence of the different wound entities was analyzed on a newly implemented three dimensional in-vitro model, which improved the transferability to the in-vivo situation. The influence of pooled wound fluids from patients suffering from acute or chronic wounds were investigated within a time period of 10 days after wound application. Histological and immunohistochemical analyses were performed addressing the impact of AWF and CWF on regeneration, such as cell proliferation, fibroblast activity and cell migration. AWF slightly stimulated fibroblast migration while CWF inhibited their activation and migration. The CXCR4- immunopositive population was continuously decreased compared to the control and AWF treatment. The expression of FAP was enhanced under AWF and medium. In keratinocytes CWF massively stimulated cell proliferation initiating on day six after injury. The presence of 10% CWF inhibited fibroblast activation and migration and induced the degradation of the collagen matrix. Keratinocytes were stimulated to proliferate, resulting in healing inhibiting hyperplasia. Transferred to human wounds, no effective wound closure would be achieved because of the de-regulation of pro-proliferative and migration-stimulating factors and a degraded extracellular matrix. This newly implemented 3D study model represents a novel appropriate in-vitro system for studying healing mechanisms and potential therapeutic applications.

Monitoring wound healing in a 3D wound model by hyperspectral imaging and efficient clustering.

Wound healing is a complex and dynamic process with different distinct and overlapping phases from homeostasis, inflammation and proliferation to remodelling. Monitoring the healing response of injured tissue is of high importance for basic research and clinical practice. In traditional application, biological markers characterize normal and abnormal wound healing. Understanding functional relationships of these biological processes is essential for developing new treatment strategies. However, most of the present techniques (in vitro or in vivo) include invasive microscopic or analytical tissue sampling. In the present study, a non-invasive alternative for monitoring processes during wound healing is introduced. Within this context, hyperspectral imaging (HSI) is an emerging and innovative non-invasive imaging technique with different opportunities in medical applications. HSI acquires the spectral reflectance of an object, depending on its biochemical and structural characteristics. An in-vitro 3-dimensional (3-D) wound model was established and incubated without and with acute and chronic wound fluid (AWF, CWF), respectively. Hyperspectral images of each individual specimen of this 3-D wound model were assessed at day 0/5/10 in vitro, and reflectance spectra were evaluated. For analysing the complex hyperspectral data, an efficient unsupervised approach for clustering massive hyperspectral data was designed, based on efficient hierarchical decomposition of spectral information according to archetypal data points. It represents, to the best of our knowledge, the first application of an advanced Data Mining approach in context of non-invasive analysis of wounds using hyperspectral imagery. By this, temporal and spatial pattern of hyperspectral clusters were determined within the tissue discs and among the different treatments. Results from non-invasive imaging were compared to the number of cells in the various clusters, assessed by Hematoxylin/Eosin (H/E) staining. It was possible to correlate cell quantity and spectral reflectance during wound closure in a 3-D wound model in vitro.

Textile Fiber Electrode to Monitor Uric Acid as a Marker for Assessing Wound Chronicity

A nanocomposite textile fiber electrode was functionalized with uricase for uric acid monitoring in chronic wound fluid. Uric acid is a metabolic product of purines which has a primary role in tissue healing by initiating the inflammatory process. Throughout the healing process, the uric acid levels are elevated in the wound fluids with relative concentrations correlating with wound chronicity. Though sensor devices implemented at point-of-care allows for rapid wound diagnostics, still there is no wearable technology for continuous monitoring. In this work, a three-dimensional high aspect ratio nanocomposite textile-based electrode was investigated. The unique structure of the electrode provided larger surface area for enzyme immobilization and an excellent platform for electron transfer from enzymatic reaction.

Designing cellulosic and nanocellulosic sensors for interface with a protease sequestrant wound-dressing prototype: Implications of material selection for dressing and protease sensor design.

Interfacing nanocellulosic-based biosensors with chronic wound dressings for protease point of care diagnostics combines functional material properties of high specific surface area, appropriate surface charge, and hydrophilicity with biocompatibility to the wound environment. Combining a protease sensor with a dressing is consistent with the concept of an intelligent dressing, which has been a goal of wound-dressing design for more than a quarter century. We present here biosensors with a nanocellulosic transducer surface (nanocrystals, nanocellulose composites, and nanocellulosic aerogels) immobilized with a fluorescent elastase tripeptide or tetrapeptide biomolecule, which has selectivity and affinity for human neutrophil elastase present in chronic wound fluid. The specific surface area of the materials correlates with a greater loading of the elastase peptide substrate. Nitrogen adsorption and mercury intrusion studies revealed gas permeable systems with different porosities (28-98%) and pore sizes (2-50 nm, 210 µm) respectively, which influence water vapor transmission rates. A correlation between zeta potential values and the degree of protease sequestration imply that the greater the negative surface charge of the nanomaterials, the greater the sequestration of positively charged neutrophil proteases. The biosensors gave detection sensitivities of 0.015-0.13 units/ml, which are at detectable human neutrophil elastase levels present in chronic wound fluid. Thus, the physical and interactive biochemical properties of the nano-based biosensors are suitable for interfacing with protease sequestrant prototype wound dressings. A discussion of the relevance of protease sensors and cellulose nanomaterials to current chronic wound dressing design and technology is included.

Detection of human neutrophil elastase (HNE) on wound dressings as marker of inflammation.

Chronic wound fluids have elevated concentration of human neutrophil elastase (HNE) which can be used as inflammation/infection marker. Our goal is to develop functional materials for fast diagnosis of wound inflammation/infection by using HNE as a specific marker. For that, fluorogenic peptides with a HNE-specific cleavage sequence were incorporated into traditional textile dressings, to allow real-time detection of the wound status. Two different fluorogenic approaches were studied in terms of intensity of the signal generated upon HNE addition: a fluorophore 7-amino-4-trifluormethylcoumarin (AFC) conjugated to a HNE-specific peptide and two fluorophore/quencher pairs (FAM/Dabcyl and EDANS/Dabcyl) coupled to a similar peptide as a Förster resonance energy transfer (FRET) strategy. Also, two immobilization methods were tested: sonochemistry immobilization onto a cotton bandage and glutaraldehyde (GTA)-assisted chemical crosslinking onto a polyamide dressing. The immobilized fluorogenic AFC peptide showed an intense fluorescence emission in the presence of HNE. HNE also induced an enhanced fluorescent signal with the EDANS/Dabcyl FRET peptide which showed to be a more sensitive and effective strategy than the AFC peptide. However, its chemical immobilization onto the polyamide dressing greatly decreased its detection, mainly due to the more difficult access of the enzyme to the cleavage sequence of the immobilized peptide. After optimization of the in situ immobilization, it will be possible to use these fluorescence-functionalized dressings for an effective and specific monitoring of chronic wounds by simply using a portable ultraviolet (UV) light source. We envision that the development of this point-of-care medical device for wound control will have a great impact on patient's life quality and reduction of costs on health care system.

Wound Healing Society 2015 update on guidelines for pressure ulcers.

Wound Healing Society 2015 update on guidelines for pressure ulcers.

Efficacy of a superabsorbent dressing with Hydration Response Technology

Moderately and heavily exuding wounds are associated with delayed healing and an increased risk of infection. Elevated proteases found in chronic wound fluid keep a sustained state of inflammation. Superabsorbent dressings can absorb large quantities of exudate without losing their structure. Some are also able to bind and sequester proteases and bacteria within their structure. This article summarises the in-vitro and clinical evidence on the efficacy of Cutimed® Sorbion® Sachet S. The findings indicate that it helps facilitate autolytic debridement, absorbs exudate and reduces inflammation, and thus the risk of infection.

The Lipid Portion of Activated Platelet-Rich Plasma Significantly Contributes to Its Wound Healing Properties.

Objective: Platelet-rich plasma (PRP) is a popular choice for the treatment of chronic wounds. Current dogma attributes these healing properties to the peptide growth factors of PRP. However, PRP is also rich in bioactive lipids whose contribution to healing has not been characterized and warrants investigation due to the protease-rich environment of chronic wounds. Approach: The lipid fraction of PRP was tested with respect to proliferation and migration of primary adult human dermal fibroblasts (HDFa)±exposure to chronic wound fluid (CWF). This fraction was also characterized via LC-MS/MS for bioactive lipids. A synthetic formulation of the bioactive lipid composition was developed and tested for the ability to overcome proliferative growth arrest induced by CWF. Results: The data demonstrate the ability of the lipid fraction of PRP to significantly enhance the migration and proliferation of HDFa, and to overcome the proliferative growth arrest induced by CWF. Furthermore, the synthetic lipid formulation generated following characterization of the PRP lipidome demonstrated a similar ability to overcome proliferative arrest of HDFa in the presence of CWF. Innovation: For the first time, we demonstrate the relevance of the lipid fraction of PRP toward the biology of wound healing. These studies open the possibility of altering the lipid profile of PRP via diet or exogenous pathway manipulation to obtain a better healing outcome. Conclusion: The lipid fraction of PRP is under investigated and yet relevant component in wound healing. The current study demonstrates the relevance of this fraction in wound healing by PRP.

The role of SDF-1 in homing of human adipose-derived stem cells.

One of the putative pathophysiological mechanisms of chronic wounds is a disturbed homing of stem cells. In this project, the stromal cell-derived factor 1 (SDF-1)/C-X-C chemokine receptor (CXCR) 4 and SDF-1/CXCR7 pathway were focused in human adipose-derived stem cells (ASCs). ASCs were incubated with acute (AWF) or chronic wound fluid (CWF) to analyze their effects by quantitative real-time polymerase chain reaction (SDF-1, CXCR4, CXCR7, TIMP3), enzyme-linked immunosorbent assay (SDF-1 in WFs and supernatant), and transwell migration assay with/without antagonization. Whereas SDF-1 amounted 73.5 pg/mL in AWF, it could not be detected in CWF. Incubation with AWF led to a significant enhancement (129.7 pg/mL vs. 95.5 pg/mL), whereas CWF resulted in a significant reduction (30 pg/mL vs. 95.5 pg/mL) of SDF-1 in ASC supernatant. The SDF-1 receptor CXCR7 was detected on ASCs. AWF but not CWF significantly induced ASC migration, which was inhibited by CXCR4 and CXCR7 antagonists. Expressions of SDF-1, CXCR4, and CXCR7 were significantly stimulated by AWF while TIMP3 expression was reduced. In conclusion, an uncontrolled inflammation in the chronic wound environment, indicated by a reduced SDF-1 expression, resulted in a decreased ASC migration. A disturbed SDF-1/CXCR4 as well as SDF-1/CXCR7 pathway seems to play an important role in the impaired healing of chronic wounds.

Matrix Metalloproteinase Profiles in Chronic Venous Ulcer Wound Fluid of Inflammatory and Granulating Venous Leg Ulcers.

Matrix Metalloproteinase Profiles in Chronic Venous Ulcer Wound Fluid of Inflammatory and Granulating Venous Leg Ulcers.