Advanced therapies for chronic wounds: NPWT, engineered skin, growth factors, extracellular matrices

Applications of blood plasma derivatives for cutaneous wound healing: A mini-review of clinical studies

Skin injuries are a global healthcare problem. Chronic ulcers do not heal in a timely fashion, so it is essential to help the body with skin repair. There are some treatments that have been applied to chronic ulcers. One of these treatments is growth factor (GF) therapy. Platelet-rich plasma (PRP) and Platelet-poor plasma (PPP) are two types of plasma derivatives containing many GFs important for wound healing. Several works have reported their application in wound healing and tissue regeneration. The use of autologous PRP is now an adequate alternative in regenerative medicine. It was also demonstrated that PPP is a hemostatic agent for wounds. This review has studied the latest clinical studies, which have applied PRP and PPP to patients with chronic wounds.

Wound Healing Efficacy of Rosuvastatin Transethosomal Gel, I Optimal Optimization, Histological and In Vivo Evaluation

This study aimed to make a formulation and statistical optimization of transethosomal formulations of rosuvastatin (ROS) to enhance its topical wound healing efficiency. Design-Expert^® software was used to employ I optimal design. The formulation variables in the study were surfactant concentration (%w/v), ethanol concentration (%w/v) and surfactant type (span 60 or tween 80), while the dependent responses were entrapment efficiency percent (EE%), vesicle size (VS) and zeta potential (ZP). The numerical optimization process employed by the design expert software resulted in an optimum formula composed of 0.819439 (%w/v) span 60, 40 (%w/v) ethanol and 100 mg lecithin with a desirability of 0.745. It showed a predicted EE% value of 66.5517 vs. 277.703 nm and a ZP of -33. When it was prepared and validated, it showed less than a 5% deviation from the predicted values. The optimum formula was subjected to further characterizations, such as DSC, XRD, TEM, in vitro release, the effect of aging and wound healing efficiency. The DSC thermogram made a confirmation of the compatibility of ROS with the ingredients used in the formulation. XRD showed the encapsulation of ROS in the transethosomal vesicles. The TEM image pointed out the spherical nature of the nanovesicles with the absence of aggregation. Additionally, the optimum formula revealed an enhancement of drug release in comparison with the drug suspension. It also showed good stability for one month. Furthermore, it revealed good wound healing efficiency when compared with the standard silver sulphadiazine (1% w/w) ointment or the drug-loaded gel, which could be related to the enhanced penetration of the nanosized vesicles of TESMs into the skin, which enhances the wound healing process. So, it could be regarded as a promising carrier of ROS for the treatment of chronic wounds.

Autologous whole blood clot and negative-pressure wound therapy in South Africa: A comparison of the cost and social considerations

BACKGROUND

Advanced wound treatment modalities enhance healing of hard-to-heal wounds, decrease the risk of amputations, and improve the quality of life of patients. Modalities have different rates of efficacy and incur different social and financial costs to the individual and the healthcare system. Two such modalities, the autologous whole blood clot (WBC) and negative-pressure wound therapy (NPWT), were compared in the South African (SA) context. The comparison was conducted on hard-to-heal wounds, with a specific focus on diabetic foot ulcers (DFUs).

OBJECTIVES

To compare the social considerations and financial costs of using autologous WBC v. NPWT in the treatment of DFUs in SA.

METHODS

Data were obtained based on current supply costs from SA suppliers for the two modalities, the standard of care for both modalities, the number of applications required for each, and social considerations provided by SA wound management clinicians. Wound healing rates were obtained from the published literature. This information was used to calculate costs of two scenarios (scenario 1: low exudate v. scenario 2: high exudate), which were compared over two treatment durations (4 and 12 weeks) for each treatment modality. Calculations included weekly cost of supplies, total cost saved by a patient with a DFU managed with either of the wound therapies, and the difference in total cost saved between the two modalities. Key social considerations were assessed qualitatively from discussions with SA clinicians experienced in both autologous WBC and NPWT, and from published research.

RESULTS

The cost of supplies per week was ZAR3 250 for autologous WBC and ZAR4 804 for NPWT in scenario 1, and ZAR3 332 and ZAR6 612 in scenario 2. With healing rates over 4 weeks' treatment duration of 19% for autologous WBC and 10% for NPWT, autologous WBC saved ZAR17 719.93, or 9% more than using NPWT, in scenario 1 and ZAR18 381.47, or 10% more, in scenario 2. At 12 weeks' treatment duration, healing rates for autologous WBC and NPWT were 75% and 43%, respectively. In scenario 1, results indicated a 43% cost difference between the two modalities. Autologous WBC had a total cost saving of ZAR61 874.40 compared with NPWT over a period of 12 weeks. In scenario 2, results indicated a 46% cost difference between the two modalities. Autologous WBC had a total cost saving of ZAR70 454.68 compared with NPWT over a period of 12 weeks. One of the identified social considerations is that NPWT needs a reliable supply of electricity to recharge the pump, while autologous WBC does not.

CONCLUSION

Both modalities are safe and effective in treating hard-to-heal wounds of the lower extremities. Autologous WBC consistently demonstrated better outcomes than NPWT in terms of both healing rate and cost-effectiveness, as well as having some advantages in terms of social considerations in SA.

Fabrication, In Vitro, and In Vivo Assessment of Eucalyptol-Loaded Nanoemulgel as a Novel Paradigm for Wound Healing

Wounds are the most common causes of mortality all over the world. Topical drug delivery systems are more efficient in treating wounds as compared to oral delivery systems because they bypass the disadvantages of the oral route. The aim of the present study was to formulate and evaluate in vitro in vivo nanoemulgels loaded with eucalyptol for wound healing. Nanoemulsions were prepared using the solvent emulsification diffusion method by mixing an aqueous phase and an oil phase, and a nanoemulgel was then fabricated by mixing nanoemulsions with a gelling agent (Carbopol 940) in a 1:1 ratio. The nanoemulgels were evaluated regarding stability, homogeneity, pH, viscosity, Fourier-transform infrared spectroscopy (FTIR), droplet size, zeta potential, polydispersity index (PDI), spreadability, drug content, in vitro drug release, and in vivo study. The optimized formulation, F5, exhibited pH values between 5 and 6, with no significant variations at different temperatures, and acceptable homogeneity and spreadability. F5 had a droplet size of 139 ± 5.8 nm, with a low polydispersity index. FTIR studies showed the compatibility of the drug with the excipients. The drug content of F5 was 94.81%. The percentage of wound contraction of the experimental, standard, and control groups were 100% ± 0.015, 98.170% ± 0.749, and 70.846% ± 0.830, respectively. Statistically, the experimental group showed a significant difference (p < 0.03) from the other two groups. The results suggest that the formulated optimized dosage showed optimum stability, and it can be considered an effective wound healing alternative.

A Comparison of the Biomechanical Performance of 3 Negative Pressure Wound Therapy Foams

PURPOSE

The purpose of this study was to compare 3 foam dressings to (1) determine the biomechanical performance of existing negative pressure wound therapy (NPWT) foams and (2) to determine if a test foam is possibly suitable as an antimicrobial "white" foam alternative for use in NPWT.

DESIGN

A comparison of mechanical performance of 3 foams used for vacuum-assisted NPWT.

SUBJECTS AND SETTING

Preclinical laboratory study using an in vitro model.

METHODS

The performance of a "white" foam (polyvinyl alcohol [PVA]), an antimicrobial "black" foam (polyurethane [PU]), and an antimicrobial white foam alternative (test PVA) were tested and compared using 3 mechanically relevant criteria. First, the fluid removal rate was measured for 72 hours. Next, the pressure input was compared to the pressure directly beneath the center of the foam. Finally, the spread of negative pressure beneath the foam was measured and compared.

RESULTS

Significant differences were found in fluid removal rates; specifically, the PU foam removed fluids faster than the PVA and test PVA foams, and the currently available PVA foams performed similarly. Both the PU and test PVA foams were able to transmit the negative pressure through the center of the dressing, while the typical PVA foam began failing at 140 mm Hg, with 50% of the samples failing at 200 mm Hg. All PU replicate foams evenly distributed the pressure, while 47% to 60% of the test PVA foams and 7% of the typical PVA foams distributed pressures evenly.

CONCLUSIONS

Study findings suggest that the test PVA foam does not mechanically interfere with NPWT and performs equivalently to currently used foams. These results suggest that the test PVA may be modified and incorporated into a vacuum-assisted NPWT device. In addition, the methods employed in these experiments provide a reproducible means to compare biomechanical compatibility of various NPWT foams, dressings, and subdrape devices.

Clinical and cost efficacy of advanced wound care matrices in the treatment of venous leg ulcers: a systematic review

BACKGROUND

Venous leg ulcers (VLUs) are hard-to-heal, recurrent and challenging to treat. Advanced wound care matrices (AWCMs) have been developed to supplement conventional therapies. These costly AWCMs warrant careful comparison as healthcare expenditures are subjected to increasing scrutiny.

AIM

This study was designed to compare AWCMs in their ability to heal VLUs and their cost efficacy through a systematic review of randomised controlled trials (RCTs).

METHOD

An organised search of Medline, Cochrane Library, Central and CINAHL databases identified RCTs that compared AWCMs to standard compression therapy in the healing of VLUs. Bias was assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies. Eight studies analysing bilayered skin substitute (BSS) (Apligraf), dehydrated human amnion/chorion membrane (dHACM) (Epifix), human fibroblast-derived dermal substitute (HFDDS) (Dermagraft), extracellular wound matrix (ECM) (Oasis), advanced matrix (AM) (Talymed) and matrix wound dressing (MWD) (Promogran) met the inclusion criteria.

RESULTS

Four studies reported significant improvement over standard therapy: BSS, dHACM, ECM and AM. Incremental cost per additional successful treatment was determined for each trial, ranging from $2593 (MWD) to $210,800 (HFDDS).

CONCLUSION

Our consolidated analysis of eight major RCTs of AWCMs in the treatment of VLUs revealed a great variation in clinical and cost efficacy among these products. The included trials were inconsistent in methodology, and these limitations should be noted, but, in the absence of RCTs to compare these products, our systematic review may serve as a guide for practitioners who seek to optimise wound healing while considering cost efficacy.

Rosuvastatin calcium-based novel nanocubic vesicles capped with silver nanoparticles-loaded hydrogel for wound healing management: optimization employing Box-Behnken design: in vitro and in vivo assessment

Chronic wounds are a serious problem that could cause severe morbidity and even death. The ability of statins including rosuvastatin calcium (RVS) to enhance wound healing was well reported. However, RVS is poorly soluble and has low bioavailability. Thus, this study aimed to prepare and evaluate RVS-loaded nanocubics to enhance its skin performance. In addition, silver nanoparticles (AgNPs) exhibited potent antimicrobial activity, thus, the optimum RVS-loaded nanocubics was capped with AgNPs to evaluate its effect in wound management. Box-Behnken design was adopted to prepare RVS nanocubics. The design investigated the effect of lecithin, poloxamer 407 concentrations and hydration time on vesicle size, zeta potential (ZP), entrapment efficiency (EE%) and in vitro drug release%. Optimum formulation capped with AgNPs was incorporated into a gel base and examined for wound healing efficiency using different pharmacological tests in rats. Nanocubics have shown a mean diameter between 167.2 ± 7.8 and 408 ± 18.4 nm, ZP values ranging from -20.9 ± 1.9 to -53.5 ± 4 mV, EE% equivocated between 31.6 ± 1.4 and 94.4 ± 8.6 and drug release after 12 h between 17.9 ± 1.9 and 68.0 ± 4.0%. The histopathological studies and serum tumour necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) levels confirmed the greater efficacy of RVS nanocubics capped with AgNPs gel in wound healing when compared with gentamicin ointment. RVS-loaded nanocubic vesicles and AgNPs-loaded hydrogel could be considered as a promising platform to enhance the wound healing and tissue repair processes.

Exploration of the role of a lithophytic fern, Pteris vittata L. in wound tissue regeneration and remodelling of genes in hyperglycaemic rat model

Background

In hyperglycemic conditions like diabetes, impaired wound healing occurs due to endothelial damage, dysfunction of leukocyte, decreased phagocytosis and secondary infection which may lead to amputation and debility. Ethnomedicinally,Pteris vittataL. (PV) is used for wound healing. This fern is arsenic hyper-accumulator but its therapeutic aspect is still unexplored. Hence, the present study was put forth to study its aqueous extract and ethanolic extract in diabetic wound healing.

Methods

Rats were divided into diabetic control, povidine iodine (PI) treated, ethanolic and aqueous extracts of PV treated groups (n = 6). Circular excision wound closure was observed for 15 days with and without treatment. After study completion, skin was divided into four sections wherein first section was homogenized for collagen, hydroxyproline and hexosamine assay. Second, third and fourth sections were used for antioxidant assay, gene expression and histopathology. Column purified fraction of ethanolic extract of PV was subjected to High Performance Liquid Chromatography, Fourier-transform infrared spectroscopy, Nuclear Magnetic Resonance and Mass spectroscopy. Data obtained were analyzed using one way analysis of variance and expressed as Mean ± SD.

Results

The percentage difference in wound area of day 15 to day 0 showed 65% wound contraction in diabetic control rats. The percentage reduction in wound area showed by PI and extracts of PV were 79% and 85% respectively. Statistical significant increase in collagen, hydroxyproline and hexosamine was observed in the test groups as compared to disease control and PI treated rats. Similarly, statistical significant increases in antioxidant enzymes were observed in the treated groups with decrease in lipid peroxidation. Treatment of rats with PI and two extracts of PV up-regulated Matrix Metalloprotein-9, Collagenase-2 and VEGF-1 and down regulated Tumor Necrosis Factor- α and Interleukin-6. Histopathology in diabetic rats showed incomplete scab formation with haemorrhages which were absent in treated rats. Spectral data showed presence of polyphenolic compounds, fatty acids and ascorbic acid.

Conclusion

Alternative and complimentary management based on herbal biotherapy which can promote angiogenesis, increase collagen and lower the levels of reactive oxygen species are warranted for healing of wounds in hyperglycaemic conditions which were achieved by two extracts of PV.

Physicochemically Tuned Myofibroblasts for Wound Healing Strategy

Normal healing of skin wounds involves a complex interplay between many different cellular constituents, including keratinocytes, immune cells, fibroblasts, myofibroblasts, as well as extracellular matrices. Especially, fibroblasts play a critical role in regulating the immune response and matrix reconstruction by secreting many cytokines and matrix proteins. Myofibroblasts, which are differentiated form of fibroblasts, feature high cellular contractility and encourage the synthesis of matrix proteins to promote faster closure of the wounds. We focus on the functional characteristics of these myofibroblasts as the healing strategy for severe wounds where the surplus amount of matrix proteins could be beneficial for better regeneration. In this study, we first employed multiple physicochemical cues, namely topographical alignment, TGF-β1, and electrical field (EF), to induce differentiation of dermal fibroblasts into myofibroblasts, and to further activate the differentiated cells. We then used these cells in a mouse wound model to verify their potential as a transplantable substitute for the severe wound. Our results confirmed that physicochemically stimulated myofibroblasts promoted faster healing of the wound compared to the case with non-stimulated myofibroblasts through elevated matrix reconstruction in the mouse model. Conclusively, we propose the utilization of physicochemically tuned myofibroblasts as a novel strategy for promoting better healing of moderate to severe wounds.

Porcine bladder extracellular matrix in paediatric pilonidal wound care: healing and patient experience evaluation

OBJECTIVE

Pilonidal disease (PD) with inflammation and abscess formation occurs frequently in adolescents. The management of pilonidal disease, time to wound healing, and patient satisfaction, however remains variable despite advances in wound care methods. Porcine bladder extracellular matrix (PBEM) facilitates site-specific tissue deposition/re-growth for the management of a variety of wounds. The aim was to describe the use and outcomes of PBEM in PD at a single centre.

METHOD

A retrospective chart review of adolescent patients who underwent treatment of pilonidal disease with PBEM between 2012 and 2016 at a single institution, was undertaken. Patient demographics and clinical characteristics were collected and compared with historical controls and literature regarding traditional wound therapies.

RESULTS

We reviewed 52 pilonidal disease wounds on 41 patients. Of these 36 were treated with PBEM. The average age was 16 years old at the time of operation with 39% male. Furthermore, 85% were being treated for recurrent pilonidal disease. Follow-up was available by chart review for 89% of patients with documented complete wound healing in 78% of patients treated with PBEM at an average of two months. Subjective reports included majority positive experience with PBEM dressing, minimal pain and overall high levels of patient satisfaction. There were three patients in which pilonidal disease recurred within two years of initial treatment and underwent repeat treatment with PBEM. There was one patient who transitioned to wet-to-dry saline dressings because of difficulty keeping the PBEM dressing intact.

CONCLUSION

Advances in wound care technology include materials such as PBEM to promote site-specific tissue deposition. Follow-up phone calls and a prospective study to compare alternative wound care with porcine PBEM in the management of pilonidal disease is underway to better quantify time to wound healing and patient satisfaction.

Treatment of human chronic wounds with autologous extracellular matrix/stromal vascular fraction gel: A STROBE-compliant study

Stem cell therapy is considered as the most promising treatment for chronic wounds. Extracellular matrix/stromal vascular fraction gel (ECM/SVF gel), an adipose-derived stem cell-based cytotherapy, has shown healing potential in experimental wounds in animal models. However, the effects of ECM/SVF gel on human chronic wounds have not been investigated. The aim of the present study is to investigate the therapeutic effect of ECM/SVF gel on human chronic wounds.Autologous ECM/SVF gel was prepared and used to treat patients with chronic wounds in clinics, with negative pressure wound therapy as the positive control. Wound healing rate per week and histological changes were performed.The average wound healing rate per week in the ECM/SVF gel group was 34.55 ± 11.18% compared with 10.16 ± 2.67% in the negative pressure wound therapy group (P < .001). Histological analysis with hematoxylin and eosin, Masson's trichrome staining, and CD31 immunohistochemistry showed less lymphocyte infiltration, more collagen accumulation, and more newly formed vessels in the ECM/SVF gel group treated skins compared to the control.ECM/SVF gel is an effective therapeutic option for chronic wound healing in clinics.

Effectiveness of viable cryopreserved placental membranes for management of diabetic foot ulcers in a real world setting

In a multicenter randomized controlled trial (RCT), the use of viable cryopreserved placental membrane (vCPM) for chronic diabetic foot ulcers (DFUs) resulted in a higher proportion of wound closure in comparison to good wound care: 62% versus 21% (p < 0.01). However, patients in RCTs are not representative of daily physician practice. Healthcare databases serve as a valuable tool to evaluate therapy effectiveness and to supplement evidence from RCTs. The objective of this study was to evaluate the effectiveness of vCPM for DFU management using Net Health's WoundExpert® electronic health records (EHR). The primary endpoint was the proportion of DFUs that achieved complete closure. Other endpoints included time and number of grafts to closure, probability of wound closure by week 12, and the number of wound-related infections and amputations. De-identified EHR data for 360 patients with 441 wounds treated with vCPM were extracted from the database. Average patient age was 63.7 years with a mean wound size of 5.1 cm² and an average wound duration of 102 days prior to vCPM treatment. For evaluation of clinical outcomes, 350 DFUs larger than 0.25 cm² at baseline were analyzed. Closure at the end of treatment was achieved in 59.4% of wounds with a median treatment duration of 42.0 days and 4 applications of vCPM. The probability of wound closure at week 12 was 71%, and the number of amputations and wound-related infections was 13 (3.0%) and 9 (2.0%), respectively. Data also demonstrated a correlation between wound size and closure rate as well as a correlation between > 50% wound area reduction by week 4 and wound closure by week 12. The results of this study mirror previous RCT efficacy data, supporting the benefits of vCPM for DFU management. These results can also influence policy and treatment decisions regarding advanced vCPM technology.

Transcriptional profile of in vitro expanded human epidermal progenitor cells for the treatment of non-healing wounds

BACKGROUND

Epidermal progenitor cells (EPCs) have been under extensive investigation due to their increasing potential of application in medicine and biotechnology. Cultured human EPCs are used in the treatment of chronic wounds and have recently became a target for gene therapy and toxicological studies. One of the challenges in EPCs culture is to provide a high number of undifferentiated, progenitor cells displaying high viability and significant biological activity.

OBJECTIVES

The goal of this study was to characterize the in vitro cultured progenitor cells and to assess whether the cells with the progenitor phenotype are able to enhance wound healing. Additionally, we aimed to establish the complete procedure of the culture, analysis and clinical application of epidermal progenitor cells.

METHODS

In this study we present a method of cell isolation and culture followed by a technique of transplantation of the cultured cells onto the wound bed. The applied isolation technique involves two enzymatic steps (dispase, trypsin) and it is characterized by a high yield of cells. The obtained cells were cultured in vitro up to the second passage in serum-free and xeno-free keratinocytes-dedicated medium. Key stem cell markers were determined with means of flow cytometry and quantitative real-time PCR.

RESULTS

The in vitro expanded cells displayed high proliferative activity without features of neither apoptosis nor necrosis. The flow cytometry and transcriptomic analyses showed enhanced expression of stem cell markers (i.e. proteins: ΔNp63, CD29, CD49f and BNC1, CDKN1A transcripts) in the expanded cells. In the presented compassionate use study, cultured autologous cells from an oncological patient were suspended in fibrin sealant and transplanted directly to a non-healing wound, resulting in wound closure within 2 months.

CONCLUSION

The cells cultured in serum-free media display epidermal stem cells features and a potential to stimulate wound healing. This promising procedure of isolation, culture and application warrants further clinical trials in the treatment of chronic wounds.

Novel use of porcine extracellular matrix in recurrent stricture following repair of tracheoesophageal fistula

Anastomotic stricture is a common complication following repair of esophageal atresia (EA). Many factors are thought to contribute to stricture formation and a variety of management techniques have been developed. In this case report, we describe the treatment of a recurrent anastomotic stricture following repair of long-gap esophageal atresia. Porcine bladder extracellular matrix (ECM) was mounted on a stent and delivered endoscopically to the site of recurrent stricture. An appropriate positioning was confirmed using direct endoscopic visualization and intra-operative fluoroscopy. The patient recovered well with persistent radiographic and functional improvements in previous stricture.

Novel use of porcine urinary bladder matrix for pediatric pilonidal wound care: preliminary experience

BACKGROUND

Extracellular matrix is used in various applications. We present our preliminary experience using a new device that consists of a porcine extracellular matrix with an epithelial basement membrane (MatriStem(®), ACell, Inc. Columbia, MD, USA) for adolescent pilonidal disease.

METHODS

A retrospective review of four patients with pilonidal disease was undertaken. Three occurred in the gluteal cleft, and the fourth in the umbilicus. In the first patient, the wound deficit was filled with lyophilized MicroMatrix powder and a sheet of Multilayer Wound Matrix was placed to cover the wound. In the second patient, two sinus tracts were debrided, packed with MicroMatrix, and a sheet of fenestrated Burn Matrix was applied. In the third patient, MicroMatrix and Surgical Matrix PSMX (six-layer) was applied as a roll filling the dead space. In the last patient, an umbilical sinus 3 cm deep was packed with MicroMatrix powder followed by a rolled sheet of 2-ply Surgical Matrix RS. Patients were evaluated weekly post-operatively, and more MicroMatrix and sheet material was added if a wound deficit was still present. Measurements were taken in two dimensions, diameter and depth, to characterize wounds.

RESULTS

Resolution of wound deficit was graphed versus time. Pain was assessed by scoring 0-10. Rapid wound closure was achieved. Two of the patients had failed wound healing with saline dressing changes prior to MatriStem application. These two patients in particular were highly satisfied with the comfort of the MatriStem approach relative to their time with saline dressings. Most had no pain after 1 week when bolster sutures were removed.

CONCLUSION

In the treatment of open pilonidal wounds in adolescents, porcine urinary bladder matrix wound care devices offer closure times and cost similar to well-established methods while offering a substantial advantage in terms of patient comfort and convenience. This preliminary experience supports a prospective study.

Intradermal injection of human adipose-derived stem cells accelerates skin wound healing in nude mice

Background

The use of stem cells from adipose tissue or adipose-derived stem cells (ASCs) in regenerative medicine could be an interesting alternative to bone marrow stem cells because they are easily accessible and available in large quantities. The aim of this study was to evaluate the potential effect of ASCs on the healing of 12 mm diameter-excisional wounds (around 110 mm²) in nude mice.

Methods

Thirty nude mice underwent surgery to create one 12-mm excisional wound per mouse (spontaneous healing, n = 6; Cytocare® 532, n = 12; ASCs, n = 12). The Galiano wound model was chosen to avoid shrinkage and thus slow the spontaneous healing (SH) of mouse skin, making it closer to the physiology of human skin healing. Transparent dressings were used to enable daily healing time measurements to be taken. Immunohistochemistry, histological and blood perfusion analysis were carried out on the healed skin.

Results

The in vivo results showed the effectiveness of using ASCs on reducing the time needed for complete healing to 21.2 days for SH, 17.4 days for vehicle alone (Cytocare® 532) and 14.6 days with the addition of ASCs (p < 0.001). Moreover, cutaneous perfusion of the healed wound was significantly improved in ASC-treated mice compared to SH group, as shown by laser Doppler flowmetry and the quantitation of blood vessels using immunohistochemistry of αsmooth muscle actin.

Conclusions

The tolerance and efficacy of cryopreserved ASCs to accelerate the complete closure of the wound by increasing the maturation of the skin and its blood perfusion, shows their therapeutic benefit in the wound healing context.

Challenges in the Treatment of Chronic Wounds

Significance: Chronic wounds include, but are not limited, to diabetic foot ulcers, venous leg ulcers, and pressure ulcers. They are a challenge to wound care professionals and consume a great deal of healthcare resources around the globe. This review discusses the pathophysiology of complex chronic wounds and the means and modalities currently available to achieve healing in such patients. Recent Advances: Although often difficult to treat, an understanding of the underlying pathophysiology and specific attention toward managing these perturbations can often lead to successful healing. Critical Issues: Overcoming the factors that contribute to delayed healing are key components of a comprehensive approach to wound care and present the primary challenges to the treatment of chronic wounds. When wounds fail to achieve sufficient healing after 4 weeks of standard care, reassessment of underlying pathology and consideration of the need for advanced therapeutic agents should be undertaken. However, selection of an appropriate therapy is often not evidence based. Future Directions: Basic tenets of care need to be routinely followed, and a systematic evaluation of patients and their wounds will also facilitate appropriate care. Underlying pathologies, which result in the failure of these wounds to heal, differ among various types of chronic wounds. A better understanding of the differences between various types of chronic wounds at the molecular and cellular levels should improve our treatment approaches, leading to better healing rates, and facilitate the development of new more effective therapies. More evidence for the efficacy of current and future advanced wound therapies is required for their appropriate use.

Growth factors in wound healing: the present and the future?

Numerous clinical studies have confirmed the pivotal role growth factors play in wound healing and their diminished levels in the chronic wound. Despite promising early studies treating chronic wounds with growth factors, results with traditional bolus dosing of a single growth factor have yielded insignificant results. Disappointing results have been theorized to be the result of growth factors inherent short half-life, a hostile microenvironment rich in protease activity, and poor delivery mechanisms failing to deliver effective dosages in an appropriate temporal manner. Advances in tissue engineering and regenerative medicine have provided technologies capable of delivering multiple growth factors in a spatially oriented approach. These technologies include polymer systems, scaffolds, and hydrogels that have demonstrated improved response by target tissues when growth factors are delivered in this biomimetic fashion. With improved delivery systems, treatment of chronic wounds with growth factors has the potential to accelerate healing in a manner not previously realized with traditional delivery approaches.

Severe complications after negative pressure wound therapy in burned wounds: two case reports

We present two typical cases of severe complications (sepsis and hemorrhage) after negative pressure wound therapy (NPWT) in burned patients. Necrotic tissues in some deep burn wounds are difficult to judge correctly and remove thoroughly. An electrically burned blood vessel looks “intact” but can easily break. Necrotic tissue or injured blood vessels when using NPWT are dangerous, both for causing sepsis and hemorrhage. This is the first article that reports the severe complications of NPWT in burned patients. It is imperative to heed indications and avoid contraindications. Proper preparation of wound beds, close observation, and sufficient irrigation are also crucial to avoid these severe complications, and there is an urgent need to substitute the central vacuum system with the low-pressure system.