Histological evolution of chronic wounds under negative pressure therapy

Basic research and clinical exploration of cold atmospheric plasma for skin wounds

Skin wounds, such as burns, diabetic foot ulcers, pressure sores, and wounds formed after laser or surgical treatment, comprise a very high proportion of dermatological disorders. Wounds are treated in a variety of ways; however, some wounds are greatly resistant, resulting in delayed healing and an urgent need to introduce new alternatives. Our previous studies have shown that cold atmospheric plasma (CAP) has antibacterial activity and promotes cell proliferation, differentiation, and migration in vitro. To further advance the role of CAP in wound healing, we evaluated the safety and efficacy of CAP in vitro by irradiation of common refractory bacteria on the skin, irradiation of normal skin of rats and observing reactions, treatment of scald wounds in rats, and treating clinically common acute wounds. Our findings revealed that CAP can eliminate refractory skin bacteria in vitro; CAP positively affected wound healing in a rat scalding wound model; and direct CAP irradiation of low intensity and short duration did not lead to skin erythema or edema. CAP promises to be a new, economical, and safe means of wound treatment.

A Multifunctional Polyethylene Glycol/Triethoxysilane-Modified Polyurethane Foam Dressing with High Absorbency and Antiadhesion Properties Promotes Diabetic Wound Healing

The delayed healing of chronic wounds, such as diabetic foot ulcers (DFUs), is a clinical problem. Few dressings can promote wound healing by satisfying the demands of chronic wound exudate management and tissue granulation. Therefore, the aim of this study was to prepare a high-absorption polyurethane (PU) foam dressing modified by polyethylene glycol (PEG) and triethoxysilane (APTES) to promote wound healing. PEG-modified (PUE) and PEG/APTES-modified (PUESi) dressings were prepared by self-foaming reactions. Gauze and PolyMem were used as controls. Next, Fourier transform-infrared spectroscopy, thermomechanical analyses, scanning electron microscopy and tensile strength, water absorption, anti-protein absorption, surface dryness and biocompatibility tests were performed for in vitro characterization. Wound healing effects were further investigated in nondiabetic (non-DM) and diabetes mellitus (DM) rat models. The PUE and PUESi groups exhibited better physicochemical properties than the gauze and PolyMem groups. Moreover, PUESi dressing showed better anti-adhesion properties and absorption capacity with deformation. Furthermore, the PUESi dressing shortened the inflammatory phase and enhanced collagen deposition in both the non-DM and DM animal models. To conclude, the PUESi dressing not only was fabricated with a simple and effective strategy but also enhanced wound healing via micronegative-pressure generation by its high absorption compacity with deformation.

Successful management of extensive stage four sacral pressure ulcer in a paraplegic patient: A case report

INTRODUCTION AND IMPORTANCE

Pressure ulcers (known as pressure injuries) occur when a bony prominence, such as the sacrum, is subjected to prolonged pressure and can result in soft tissue injury. Continuous and attentive repositioning is necessary to prevent and cure pressure-induced wounds.

CASE PRESENTATION

A 49-year-old patient who presented to the hospital with a case of paraplegia post spinal injury due to Road Traffic Accident, with a huge infected sacral bed sore and complaints of generalized weakness and fever. His ulcer was 15 cm ∗ 15 cm ∗ 8 cm, grade 4. He underwent flap reconstruction, was post-operatively transferred into the ward, and started on IV antibiotics and analgesia. The flap is well vascularized with no signs of infection or dehiscence.

CLINICAL DISCUSSION

Wound management begins with the identification and aggressive management of the modifiable factors, such as positioning, incontinence, spasticity, diet, devices, and medical comorbidity, which contribute to pressure injury formation. Initial interventions include washing, cleaning, and maintaining the surfaces of the wound. In certain cases, it may be sufficient to debride the non-viable or contaminated tissue. However, operational care in more severe cases or to encourage patient satisfaction may be necessary.

CONCLUSION

The bilobed flap is the best technique for healing sacral pressure ulcers. It has a plentiful supply of blood. The layout is uncomplicated and straightforward. The fact that it has a low risk of complications is crucial. It ought to be taken into account as a component of the local flap arsenal for sacral pressure ulcers.

Characterization of Immunogenicity Associated with the Biocompatibility of Type I Collagen from Tilapia Fish Skin

Collagen from fish has been proven to have a low antigenicity that has no difference in the genetic codes compared with mammalian-based collagen. This study was designed to investigate the impact of tilapia skin collagen on immunogenicity and biocompatibility in vivo and in vitro. The structural characteristics of both acid-soluble and pepsin-soluble collagen (ASC and PSC), determined using SDS-PAGE and atomic force microscopy imaging experiments, revealed that the collagen had the basic characteristics of type I collagen (COL-I). The in vitro biocompatibility of the collagens showed good cell proliferation against human foreskin fibroblast (HFF-1) cells. PSC and ASC were considered to be almost non-hemolytic biomaterials with favorable blood compatibility in hemolysis tests. The in vivo antigenicity of the collagen in an ICR mouse model evoked an acceptable specific inflammatory response compared to bovine collagen. The implant’s position had developed a complete granulation tissue and the sponge disappeared after 8 weeks. The level of cytokines produced by the COL-I immune response was much lower than bovine collagen, which indicated the appropriate implantable property and biodegradability of the collagens. In conclusion, the tilapia COL-I has a lower immunogenicity with better compatibility than bovine COL-I and is a potential alternative to conventional mammalian collagens in biomedical uses.

Notoginsenoside R1 Facilitated Wound Healing in High-Fat Diet/Streptozotocin-Induced Diabetic Rats

Diabetic ulcers bring about high morbidity and mortality in patients and cause a great economic burden to society as a whole. Since existing treatments cannot fulfil patient requirements, it is urgent to find effective therapies. In this study, the wound healing effect of topical notoginsenoside R1 (NR1) treatment on diabetic full-thickness wounds in type II diabetes mellitus (T2DM) was induced by the combination of a high-fat diet and streptozotocin (STZ) injection. NR1 significantly increased the wound closure rate, enhanced extracellular matrix (ECM) secretion, promoted collagen growth, increased platelet endothelial cell adhesion molecule-1 (CD31) expression, and decreased cleaved caspase-3 expression. RNA-Seq analysis identified ECM remodeling and inflammation as critical biological processes and Timp1 and Mmp3 as important targets in NR1-mediated wound healing. Further experiments showed that NR1-treated wounds demonstrated higher expression of tissue inhibitor of metalloproteinase 1 (TIMP1) and transforming growth factor-β1 (TGFβ1) and lower expression of matrix metallopeptidase 9 (MMP9), matrix metallopeptidase 3 (MMP3), interleukin-1β (IL-1β), and interleukin-6 (IL-6) than diabetic wounds. These investigations promote the understanding of the mechanism of NR1-mediated diabetic wound healing and provide a promising therapeutic drug to enhance diabetic wound healing.

The Role of Negative Pressure Wound Therapy (NPWT) in the Management of Vasculitic Wounds: Case Series of Eight Patients

Vasculitic ulcers belong to the category of atypical ulcers and are traditionally very slow to heal. The aim of this study is to retrospectively analyze the files of eight patients with vasculitic ulcers treated with negative pressure wound therapy (NPWT). Immunosuppression was initiated at least two weeks prior to starting NPWT. We suggest that this is a safe and promising protocol to treat these hard-to-heal ulcers.

Skin Wound Healing Process and New Emerging Technologies for Skin Wound Care and Regeneration

Skin wound healing shows an extraordinary cellular function mechanism, unique in nature and involving the interaction of several cells, growth factors and cytokines. Physiological wound healing restores tissue integrity, but in many cases the process is limited to wound repair. Ongoing studies aim to obtain more effective wound therapies with the intention of reducing inpatient costs, providing long-term relief and effective scar healing. The main goal of this comprehensive review is to focus on the progress in wound medication and how it has evolved over the years. The main complications related to the healing process and the clinical management of chronic wounds are described in the review. Moreover, advanced treatment strategies for skin regeneration and experimental techniques for cellular engineering and skin tissue engineering are addressed. Emerging skin regeneration techniques involving scaffolds activated with growth factors, bioactive molecules and genetically modified cells are exploited to overcome wound healing technology limitations and to implement personalized therapy design.

[Effect of decellularized adipose tissue combined with vacuum sealing drainage on wound inflammation in pigs]

Objective

To preliminary explore the effect of decellularized adipose tissue (DAT) combined with vacuum sealing drainage (VSD) on wound inflammation in pigs.

Methods

The DAT was prepared through the process of freeze-thaw, enzymatic digestion, organic solvent extraction, and vacuum freeze-drying. The appearance of DAT was observed before and after freeze-drying. HE staining was used to observe its structure and acellular effect. Eighteen male Bama minipigs were recruited, and four dorsal skin soft tissue wounds in diameter of 4 cm were made on each pig and randomly divided into 4 groups for different treatments. The wounds were treated with DAT combined with VSD in DAT/VSD group, DAT in DAT group, VSD in VSD group, and sterile gauze dressing in control group. HE staining was performed at 3, 7, 10, and 14 days after treatment. Moreover, the expressions of inflammatory factors [interleukin 1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)], as well as the phenotypes of M1 and M2 macrophage phenotypic markers [inducible nitric oxide synthase (iNOS) and arginase 1 (ARG-1)] were detected by real-time fluorescence quantitative PCR (qRT-PCR). ELISA was used to determine the content of iNOS and ARG-1.

Results

General observation and HE staining showed that DAT obtained in this study had a loose porous structure without cells. The neutrophils of wounds were significantly less in DAT/VSD group than in control group and DAT group ( P<0.05) at 3 days after treatment, and the difference was not significant ( P>0.05) between DAT/VSD group and VSD group. And the neutrophils were significantly less in DAT/VSD group than in other three groups ( P<0.05) at 7, 10, and 14 days. The mRNA expressions of IL-1β, IL-6, TNF-α, and iNOS were significantly lower in DAT/VSD group than in other three groups at 3, 7, 10, and 14 days ( P<0.05), while the mRNA expression of ARG-1 was significantly higher in DAT/VSD group than in other three groups ( P<0.05). ELISA showed that the content of iNOS was significantly lower in DAT/VSD group than in other three groups at 3, 7, 10, and 14 days ( P<0.05), while the content of ARG-1 was significantly higher in DAT/VSD group than in other three groups ( P<0.05).

Conclusion

DAT combined with VSD can significantly reduce inflammatory cell infiltration during wound healing, regulate the expressions of inflammatory factors and macrophage phenotype, and the effect is better than single use of each and conventional dressing change.

Instructive microenvironments in skin wound healing: Biomaterials as signal releasing platforms

Skin wound healing aims to repair and restore tissue through a multistage process that involves different cells and signalling molecules that regulate the cellular response and the dynamic remodelling of the extracellular matrix. Nowadays, several therapies that combine biomolecule signals (growth factors and cytokines) and cells are being proposed. However, a lack of reliable evidence of their efficacy, together with associated issues such as high costs, a lack of standardization, no scalable processes, and storage and regulatory issues, are hampering their application. In situ tissue regeneration appears to be a feasible strategy that uses the body's own capacity for regeneration by mobilizing host endogenous stem cells or tissue-specific progenitor cells to the wound site to promote repair and regeneration. The aim is to engineer instructive systems to regulate the spatio-temporal delivery of proper signalling based on the biological mechanisms of the different events that occur in the host microenvironment. This review describes the current state of the different signal cues used in wound healing and skin regeneration, and their combination with biomaterial supports to create instructive microenvironments for wound healing.

[Effects of long time different negative pressures on osteogenic differentiation of rabbit bone mesenchymal stem cells]

Objective

To investigate the effects of long time different negative pressures on osteogenic diffe-rentiation of rabbit bone mesenchymal stem cells (BMSCs).

Methods

The rabbit BMSCs were isolated and cultured by density gradient centrifugation. Flow cytometry was used to analyze expression of surface markers. The third passage cells cultured under condition of osteogenic induction and under different negative pressure of 0 mm Hg (control group), 75 mm Hg (low negative pressure group), and 150 mm Hg (high negative pressure group) (1 mm Hg=0.133 kPa), and the negative pressure time was 30 min/h. Cell growth was observed under phase contrast microscopy, and the growth curve was drawn; alkaline phosphatase (ALP) activity was detected by ELISA after induced for 3, 7, and 14 days. The mRNA and protein expressions of collagen type I (COL-I) and osteocalcin (OC) in BMSCs were analyzed by real-time fluorescence quantitative PCR and Western blot.

Results

The cultured cells were identified as BMSCs by flow cytometry. The third passage BMSCs exhibited typical long shuttle and irregular shape. Cell proliferation was inhibited with the increase of negative pressure. After induced for 4 days, the cell number of high negative pressure group was significantly less than that in control group and low negative pressure group ( P<0.05), but there was no significant difference between the low negative pressure group and the control group ( P>0.05); at 5-7 days, the cell number showed significant difference between 3 groups ( P<0.05). The greater the negative pressure was, the greater the inhibition of cell proliferation was. There was no significant difference in ALP activity between groups at 3 days after induction ( P>0.05); the ALP activity showed significant difference ( P<0.05) between the high negative pressure group and the control group at 7 days after induction; and significant difference was found in the ALP activity between 3 groups at 14 days after induction ( P<0.05). The greater the negative pressure was, the higher the ALP activity was. Real-time fluorescence quantitative PCR and Western blot detection showed that the mRNA and protein expressions of COL-I and OC protein were significantly higher in low negative pressure group and high negative pressure group than control group ( P<0.05), and in the high negative pressure group than the low negative pressure group ( P<0.05).

Conclusion

With the increase of the negative pressure, the osteogenic differentiation ability of BMSCs increases gradually, but the cell proliferation is inhibited.

[Comparative evaluation of the intensity of reparative processes in the lower extremity soft tissues of diabetic patients receiving local negative pressure wound treatment and standard wound care]

AIM

To study the intensity of soft tissue repair in patients with diabetic foot syndrome (DFS) during local negative pressure wound treatment versus standard wound care.

SUBJECTS AND METHODS

The investigators estimated the clinical (wound sizes, local tissue oxygenation), histological (light microscopy), and immunohistochemical (CD31, CD68, MMP-9, and TIMP-1) markers for reparative processes in patients with DFS during vacuum therapy versus standard wound care. Forty-two patients with the neuropathic and neuroischemic (without critical ischemia) forms of DFS were examined after debridement. In the perioperative period, 21 patients received negative pressure wound therapy and 21 had standard wound care.

RESULTS

During vacuum therapy, the area and depth of wound defects decreased by 19.8±7.8 and 42.8±5.6%, respectively (p=0.002) (as compared to the baseline data). In the control group, these indicators were 17.0±19.4 and 16.6±21.6% (p=0.002). There was a significant intensification of local microhemodynamics according to transcutaneous oximetry readings in the negative pressure wound treatment group. After 9±2 days of treatment, histological examination of granulation tissue revealed a significant reduction in edema, cessation of inflammatory infiltration, and formation of mature granulation tissue in Group 1. Immunohistological examination indicated a more obvious increase in the count of macrophages (CD68 staining) and a significant increment in the number of newly formed vessels, as evidenced by anti-CD31 antibody staining. During the treatment, there was a decline of the expression of MMP-9 and an increase in that of TIMP-1, as compared to those in the control group.

CONCLUSION

The findings are indicative of the enhanced intensity of reparative processes in patients with DFS during vacuum therapy versus standard wound care, resulting in more rapidly decreased wound sizes, increased local microhemodynamics, reduced inflammation, and accelerated wound transition from the inflammatory to the proliferative phase.

Bilayered negative-pressure wound therapy preventing leg incision morbidity in coronary artery bypass graft patients: A randomized controlled trial

BACKGROUNDS

The harvesting of great saphenous veins for coronary artery bypass graft (CABG) patients may result in significant complications, including lymphorrhagia, lymphoedema, incision infection, wound dehiscence, and skin flap necrosis. We investigated the function of a self-designed bilayered negative pressure wound therapy (b-NPWT) for reducing the above-mentioned complications using a clinical randomized controlled trial.

METHODS

A single-center, pilot randomized controlled trial was conducted. From December 2013 to March 2014, a total of 72 coronary heart disease patients (48 men and 24 women) received CABG therapy, with great saphenous veins were selected as grafts. Patients were equally randomized into a treatment and a control group. After the harvesting of the great saphenous veins and direct closure of the wound with sutures, b-NPWT was used for the thigh incision in the treatment group for 5 days (treatment thigh). Traditional surgical pads were applied to both the shank incisions of the treatment group patients (treatment shank) and the entire incisions of the control group (control thigh, control shank). Postoperative complications were recorded and statistically analyzed based on outcomes of thigh treatment, shank treatment, thigh control, and shank control groups.

RESULTS

The incidence rates of early complications, such as lymphorrhagia, lymphoedema, infection, wound dehiscence, and skin flap necrosis, of the vascular donor site in the thigh treatment group was significantly lower than those in the 3 other groups.

CONCLUSIONS

The self-designed b-NPWT can effectively reduce postoperative complications, such as lymphedema, incision infection, wound dehiscence, and skin flap necrosis, in CABG patients who underwent great saphenous veins harvesting.

TRIAL REGISTRATION

ClinicalTrials.gov. The unique registration number is NCT02010996.

Negative-pressure wound therapy enhances local inflammatory responses in acute infected soft-tissue wound

Clinical studies found that negative-pressure wound therapy (NPWT) displayed significant clinical benefits in the healing of infected wounds. However, the effect of NPWT on local inflammatory responses in acute infected soft-tissue wound has not been investigated thoroughly. The purpose of this study was to test the impact of NPWT on local expression of proinflammatory cytokines, amount of neutrophils, and bacterial bioburden in wound from acute infected soft-tissue wounds. Full-thickness wounds were created on the back of rabbits, and were inoculated with Staphylococcus aureus strain ATCC29213. The wounds were treated with sterile saline-moistened gauze dressings and NPWT with continuous negative pressure (-125 mmHg). Wound samples were harvested on days 0 (6 h after bacterial inoculation), 2, 4, 6, and 8 at the center of wound beds before irrigation for real-time PCR analysis of gene expression of IL-1β, IL-8, and TNF-α. Wound biopsies were examined histologically for neutrophil quantification in different layers of tissue. Quantitative bacterial cultures at the same time point were analyzed for bacterial clearance. Application of NPWT to acute infected wounds in rabbits was compared with treatment with sterile saline-moistened gauze, over an 8-day period. NPWT-treated wounds exhibited earlier and greater peaking of IL-1β and IL-8 expression and decrease in TNF-α expression over the early 4 days (P < 0.05). Furthermore, histologic examination revealed that significantly increased neutrophil count was observed in the shallow layer in wound biopsies of NPWT treatment at day 2 (P < 0.001). In addition, there was a statistically significant decrease of bacteria load from baseline (day 0) at days 2 and 8 in NPWT group (P < 0.05). In conclusion, this study demonstrates that NPWT of acute infected soft-tissue wounds leads to increased local IL-1β and IL-8 expression in early phase of inflammation, which may trigger accumulation of neutrophils and thus accelerate bacterial clearance. Meanwhile, the success of NPWT in the treatment of acute wounds can attenuate the expression of TNF-α, and the result may partly explain how NPWT can avoid significantly impairing wound healing.

Curbing Inflammation in Skin Wound Healing: A Review

Wound healing is a complex regulated process that results in skin scar formation in postnatal mammals. Chronic wounds are major medical problems that can confer devastating consequences. Currently, there are no treatments to prevent scarring. In the early fetus wounds heal without scarring and the healing process is characterized by relatively less inflammation compared to adults; therefore, research aimed at reducing the inflammatory process related to wound healing might speed healing and improve the final scar appearance.

Negative pressure wound therapy is associated with up-regulation of bFGF and ERK1/2 in human diabetic foot wounds

Chronic foot wounds are a leading cause of morbidity and hospitalization for patients with diabetes. Negative pressure wound therapy (NPWT) is known to promote healing of diabetic foot wounds, but the underlying molecular mechanisms remain elusive. We propose to gain molecular insights into the wound healing promoting signals underlying the effects of NPWT on diabetic foot wounds in humans. We assessed 30 patients with diabetic foot ulcers. Of these cases, 15 were treated with NPWT, while 15 patients were treated with traditional gauze therapy. Granulated tissue was harvested before and after treatment in both patient groups and histologically analyzed with hematoxylin & eosin as well as Masson's trichrome staining methods. Immunohistochemistry and Western blot analysis was performed to evaluate expression of basic fibroblast growth factor (bFGF) and extracellular signal-regulated kinase (ERK)1/2, previously associated with promoting cellular growth and/or wound healing. Unlike controls, the wounds in the NPWT-treated diabetic patients developed characteristic features of granulated tissue with increased collagen deposition. Immunohistochemical analysis also revealed an increase in bFGF levels in NPWT-treated patients. Western blot analysis further showed a significant up-regulation of bFGF and phosphorylated ERK1/2 protein levels in the NPWT-treated diabetic patients vs. controls. Our studies reveal that NPWT is associated with an up-regulation of bFGF and ERK1/2 signaling, which may be involved in promoting the NPWT-mediated wound healing response.

Growth factors, silver dressings and negative pressure wound therapy in the management of hard-to-heal postoperative wounds in obstetrics and gynecology: a review

Purpose

The last two decades witnessed the development of numerous innovative regimens for the management of patients with abnormally healing and infected wounds. Growth factors, negative pressure wound therapy (NPWT) and antiseptic dressings containing silver are examples of methods with best documented efficacy, being widely used in the treatment of acute and chronic post-traumatic wounds, burns and ulcers of various etiology. As far as obstetrics and gynecology are concerned, prevention and treatment of infected, hard-to-heal postoperative wounds is of crucial importance. This article reviews the available literature to discuss the possibilities for use, efficacy and cost-effectiveness of growth factors, NPWT and silver dressings in the treatment of difficult-to-heal postsurgical wounds in obstetrics and gynecology.

Materials and methods

An extensive search of the English and Polish literature via PubMed and EMBASE databases was undertaken for articles published between January 1960 and April 30, 2014 to identify articles that described and assessed use, efficacy and cost-effectiveness of growth factors, silver dressings and NPWT in patients with hard-to-heal postoperative wounds following obstetric or gynecological surgery.

Conclusions

Literature review regarding the use of growth factors, NPWT and silver dressings suggests that these methods may play an important role in the management of wounds after invasive obstetric and gynecological procedures. Obese patients, patients after vulvectomy or prior radiation therapy may benefit most, however, due to non-numerous randomized reports, prospective studies on the use of above-mentioned methods in the treatment of postsurgical wounds following obstetric and gynecological interventions are required.

Mechanoregulation of Angiogenesis in Wound Healing

Significance: Mechanical forces are important regulators of cell and tissue function. Endothelial cells proliferate in response to tissue stretch and the mechanical properties of the environment direct capillary sprouting and growth. As the vascular network is a key factor in physiology and disease, control of the vascularity by means of mechanical forces could lead to the development of innovative therapeutic strategies. Recent Advances: Increased understanding of mechanobiology has stimulated translational research and allowed the development and optimization of clinical devices that exploit mechanical forces for the treatment of diseases, in particular in the field of wound healing. Stretching in distraction osteogenesis and tissue expansion induces neogenesis of well-vascularized tissues. In micro-deformational wound therapy, micro-mechanical distortions of the wound bed stimulate cell proliferation and angiogenesis by stretching resident cells to improve healing of difficult wounds. Relief from tension antagonizes proliferation and angiogenesis in primarily closed wounds allowing for better scar quality. Critical Issues: The integration of mechanobiology into traditional cell biology and pathophysiology in general is not yet complete and further research is needed to fill existing gaps, in particular in the complexity of in vivo conditions. Future Directions: Still largely unexplored approaches based on mechanical perturbation of the micro-/macro-environment can be devised to overcome the limits of current strategies in a broad spectrum of clinical conditions.

The enhanced healing of a high-risk, clean, sutured surgical incision by prophylactic negative pressure wound therapy as delivered by Prevena™ Customizable™: cosmetic and therapeutic results

According to the literature, incisional closure complications may range from postoperative surgical site infections, representing 17-22% of health care-associated infections, surgical wound dehiscence and formation of haematomas or seromas, and can lead to delayed or impaired incision healing. These kinds of situations are more common when wounds are closed under tension or in specific patient morbidities. Obesity, in particular, is associated with an impaired blood flow to tissues, predisposing the patient to increased risk of wound complications by various mechanisms. Incisional complications can become relevant economic burdens for health care systems because of an increase in the average length of hospital stay and readmissions, and additional medical and surgical procedures. Thus, a preventive therapy may have a critical role in the management of healing. Negative pressure wound therapy (NPWT) technology as delivered by Prevena™ Customizable™ (Kinetic Concepts Inc., San Antonio, TX) has recently been the focus of a new investigation, as a prophylactic measure to prevent complications via immediate postoperative application in high-risk, clean, closed surgical incisions. The authors present a 62-year-old class II obese female, who underwent bilateral inguinal dermolipectomy. Prophylactic NPWT as delivered by Prevena™ was performed successfully over surgical incisions. Cosmetic and therapeutic results are shown.

VAC Therapy in Large Infected Sacral Pressure Ulcer Grade IV-Can Be an Alternative to Flap Reconstruction?

Vacuum-assisted closure (VAC) therapy is a new entrant in wound care after growth factors and alginate or hydrocolloid dressing, in the treatment of pressure ulcers. We have been using this technique for diabetic foot ulcers. A young nondiabetic man presented with a large sacral bed sore after high doses of ionotropes in an intensive care unit for treating severe hypotension. His wound was debrided, and instead of flap surgery in such infected wound, he was treated with VAC therapy. The complete wound healing was achieved in 6 weeks and at half the cost of flap surgery. Moreover, the chances of flap failure and its related complications were eliminated.

Early kinetics of integration of collagen-glycosaminoglycan regenerative scaffolds in a diabetic mouse model

BACKGROUND

Collagen-glycosaminoglycan scaffolds, originally designed to treat severe burns, are now commonly used in patients with complex wounds associated with diabetes mellitus. In this study, the authors investigated how the thickness of the scaffold would affect cellular integration with the diabetic host and whether this can be accelerated using subatmospheric pressure wound therapy devices.

METHODS

Collagen-glycosaminoglycan scaffolds, 500 to 2000-μm thick, were applied to dorsal wounds in genetically diabetic mice. In addition, 1000-μm collagen-glycosaminoglycan scaffolds with and without silicone were treated with a subatmospheric pressure device (-125 mmHg). On days 5 and 10, cellular and vascular integration of tissues was studied by histology, immunohistochemistry, corrosion casting, and qRT-polymerase chain reaction.

RESULTS

Cells and vessels from the wound surface populated the scaffold to form layers with varying cellular density. Areas of high cell density and proliferation were noted at the bottom of the scaffold. Increasing the thickness of the scaffold did not affect the extent of cellular ingrowth, so that thicker scaffolds had a thicker residual acellular layer on the surface. The thickness of cellular ingrowth was stable between days 5 and 10, whereas vessels seen in the scaffolds on day 10 were not yet present on day 5. Subatmospheric pressure devices applied to silicone-covered collagen-glycosaminoglycan scaffolds minimized the granulation tissue formation beneath the scaffold, which enhanced vessel ingrowth.

CONCLUSIONS

The early kinetics of cellular integration into collagen-glycosaminoglycan scaffolds is independent of scaffold thickness in a diabetic wound model. Scaffold adherence to the wound and integration can be improved using a subatmospheric pressure device.

MUC1 has prognostic significance in malignant peritoneal mesothelioma

BACKGROUND

Overexpression of MUC1 predicts poor survival in most cancers. Routine immunohistochemical detection of MUC1 is performed for differential diagnosis in malignant peritoneal mesothelioma (MPM). However, the prognostic significance of MUC1 in MPM has not been determined. 


METHOD

We investigated MUC1 expression and other prognostic factors in relation to survival in 42 patients (20 males and 22 females) for whom archival samples were available, using immunohistochemistry. MUC1 was expressed in 38/42 (90%) patients. Its prognostic significance was statistically analyzed using the Kaplan-Meier method.


RESULTS

High expression of MUC1 (immunohistochemical score of 5-8), was correlated with poor survival in several categories: all subtypes of tumors (p=0.001), male gender (p=0.017), female gender (p=0.001), epitheloid tumors (p=0.001), epitheloid tumors in males (p=0.005), epitheloid tumors in females (p=0.003), and age at diagnosis (AAD) <60 years (p=0.001). Amongst the other clinicopathological variables, univariate analysis also showed that male gender (p=0.007), sarcomatoid histology (p=0.001), peritoneal cancer index (PCI) ≥20 (p=0.013) and AAD ≥60 (p=0.001), correlated with poor survival. Multivariate analysis showed that only AAD ≥60 (p=0.049) was an independent prognostic factor, and that high MUC1 expression significantly correlated with the following categories: all subtypes of tumors (p=0.001), male gender (p=0.002), female gender (p=0.031), epitheloid tumors (p=0.031), and AAD <60y (p=0.012).


CONCLUSION

AAD and high MUC1 expression in the tumor are indicators of poor prognosis. MUC1 evaluation by immunohistochemistry may serve as a useful prognostic tool in MPM, but may need further confirmation in a larger patients' cohort.

Extending the TIME concept: what have we learned in the past 10 years?(*)

The TIME acronym (tissue, infection/inflammation, moisture balance and edge of wound) was first developed more than 10 years ago, by an international group of wound healing experts, to provide a framework for a structured approach to wound bed preparation; a basis for optimising the management of open chronic wounds healing by secondary intention. However, it should be recognised that the TIME principles are only a part of the systematic and holistic evaluation of each patient at every wound assessment. This review, prepared by the International Wound Infection Institute, examines how new data and evidence generated in the intervening decade affects the original concepts of TIME, and how it is translated into current best practice. Four developments stand out: recognition of the importance of biofilms (and the need for a simple diagnostic), use of negative pressure wound therapy (NPWT), evolution of topical antiseptic therapy as dressings and for wound lavage (notably, silver and polyhexamethylene biguanide) and expanded insight of the role of molecular biological processes in chronic wounds (with emerging diagnostics and theranostics). Tissue: a major advance has been the recognition of the value of repetitive and maintenance debridement and wound cleansing, both in time-honoured and novel methods (notably using NPWT and hydrosurgery). Infection/inflammation: clinical recognition of infection (and non infective causes of persisting inflammation) is critical. The concept of a bacterial continuum through contamination, colonisation and infection is now widely accepted, together with the understanding of biofilm presence. There has been a return to topical antiseptics to control bioburden in wounds, emphasised by the awareness of increasing antibiotic resistance. Moisture: the relevance of excessive or insufficient wound exudate and its molecular components has led to the development and use of a wide range of dressings to regulate moisture balance, and to protect peri-wound skin, and optimise healing. Edge of wound: several treatment modalities are being investigated and introduced to improve epithelial advancement, which can be regarded as the clearest sign of wound healing. The TIME principle remains relevant 10 years on, with continuing important developments that incorporate new evidence for wound care.

Optimal use of negative pressure wound therapy for skin grafts

Skin grafting is a technique used for transplanting human skin (i.e. epidermal and some dermal layers) from a harvest site to a recipient site. However, advancements in bioengineered matrices have also introduced alternatives to skin grafts. The method used to secure the graft, whether skin or biomatrix, is critical in reducing graft failure. During the past several years, negative pressure wound therapy using reticulated open-cell foam (NPWT/ROCF; V.A.C.® Therapy, KCI USA, Inc., San Antonio, TX) has become a well-established method for bolstering grafts to recipient beds and is being used more frequently over biomatrices to help improve graft outcomes. This review will combine expert opinion with scientific evidence for the use of NPWT/ROCF over grafts.

Mechanisms of action of microdeformational wound therapy

Microdeformational Wound Therapy (MDWT) is a class of medical devices that have revolutionized the treatment of complex wounds over the last 20 years. These devices, are a subset of Negative Pressure Wound Therapy (NPWT), in which there is a highly porous interface material placed between the wound and a semi-occlussive dressing and connected to suction. The porous interface material acts to deform the wound on a micro scale promoting cellular proliferation. These devices appear to significantly improve the speed of healing in many wounds, facilitate granulation tissue formation and reduce the complexity of subsequent reconstructive operations. The mechanisms through which such effects are obtained are beginning to be better understood through basic research and clinical trials. Further work in this field is likely to yield devices that are designed to treat specific wound types.

Silicone-coated non-woven polyester dressing enhances reepithelialisation in a sheep model of dermal wounds

Negative-pressure wound therapy (NPWT) also known as V.A.C. (Vacuum-assisted closure), is widely used to manage various type of wounds and accelerate healing. NPWT has so far been delivered mainly via open-cell polyurethane (PU) foam or medical gauze. In this study an experimental setup of sheep wound model was used to evaluate, under NPWT conditions, the performance of a silicone-coated non-woven polyester (N-WPE) compared with PU foam and cotton hydrophilic gauze, used as reference materials. Animals were anesthetized with spontaneous breathing to create three 3 × 3 cm skin defects bilaterally; each animal received three different samples on each side (n = 6 in each experimental group) and was subjected to negative and continuous 125 mmHg pressure up to 16 days. Wound conditions after 1, 8 and 16 days of treatment with the wound dressings were evaluated based on gross and histological appearances. Skin defects treated with the silicone-coated N-WPE showed a significant decrease in wound size, an increase of re-epithelialization, collagen deposition and wound neovascularisation, and a minimal stickiness to the wound tissue, in comparison with gauze and PU foam. Taken all together these findings indicate that the silicone-coated N-WPE dressing enhances wound healing since stimulates higher granulation tissue formation and causes minor tissue trauma during dressing changes.

Gauze-based negative pressure wound therapy: a valid method to manage pyoderma gangrenosum

Pyoderma gangrenosum (PG) is an uncommon ulcerative, non-infective chronic inflammatory skin disorder of unknown aetiology. Systemic therapies are necessary to control the associated medical diseases, and, due to the inflammatory nature of PG, topical or systemic immunosuppressant agents are effective, but wound healing is usually slow. Negative wound pressure therapy (NPWT) has become an important tool for the management of complex skin ulcers, and usage in PG has been recently described in the literature: we present four cases of classic PG in which NPWT in association with systemic therapy achieved wound healing and a drastic pain reduction.