Extensive traumatic soft tissue loss: reconstruction in severely injured patients using cultured hyaluronan-based three-dimensional dermal and epidermal autografts

Quaternized oxidized sodium alginate injectable hydrogel with high antimicrobial and hemostatic efficacy promotes diabetic wound healing

In this paper, a hydrogel material with efficient antibacterial, hemostatic, self-healing, and injectable properties was designed for the treatment of diabetic wounds. Firstly, quaternary ammonium salts were grafted with oxidized sodium alginate, and quaternized oxidized sodium alginate (QOSA) was synthesized. Due to the introduction of quaternary ammonium group it has antibacterial and hemostatic effects, at the same time, due to the presence of aldehyde group it can be reacted with carboxymethyl chitosan (CMCS) to form a hydrogel through the Schiff base reaction. Furthermore, deer antler blood polypeptide (DABP) was loaded into the hydrogel (QOSA&CMCS&DABP), showing good swelling ratio and bacteriostatic effect. In vitro and in vivo experiments demonstrated that the hydrogel not only quickly inhibited hepatic hemorrhage in mice and reduced coagulation index and clotting time in vitro, but also significantly enhanced collagen deposition at the wound site, accelerating wound healing. This demonstrates that the multifunctional hydrogel materials (QOSA&CMCS&DABP) have promising applications in the acceleration of skin wound healing and antibacterial promotion.

Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition

The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92° and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80-56° and surface energy and roughness increased to 41-57 mN/m and 172-290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76-80°) and reduced roughness parameters (to 40-45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67-76°), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment.

Preparation and characterisation of a novel silk fibroin/hyaluronic acid/sodium alginate scaffold for skin repair

To mimic the natural structure of tissue extracellular matrix, a novel silk fibroin (SF)/hyaluronic acid (HA)/sodium alginate (SA) composite scaffold (92% in porosity) was prepared by freeze-drying. Fourier-transform infrared spectroscopy and Raman spectra indicated interactions among SF, HA, and SA molecules. Scanning electron microscopy showed that the prepared SF/HA/SA scaffold had soft, elastic characteristics, with an average pore diameter of 93 μm. Mechanical property, thermogravimetric analyses and degradation results indicated that the SF/HA/SA scaffold had good physical stability in body fluid and mechanical movement-related environments. Cell proliferation, morphological, and live-dead analyses showed that NIH-3T3 fibroblast cells were better able to attach, grow, and proliferate on the SF/HA/SA scaffold compared with SF, SF/HA, and SF/SA scaffolds. We evaluated the wound healing effects in a rat full-thickness burn model. The hematoxylin-eosin (H&E) and Masson's trichrome staining results from SF/HA/SA scaffold showed that improved re-epithelialization, enhanced extracellular matrix remodeling. Our findings showed that the prepared SF/HA/SA scaffold can provide a potential way as a wound dressing for skin repair.

Biomaterials for Skin Substitutes

Patients with extensive burns rely on the use of tissue engineered skin due to a lack of sufficient donor tissue, but it is a challenge to identify reliable and economical scaffold materials and donor cell sources for the generation of a functional skin substitute. The current review attempts to evaluate the performance of the wide range of biomaterials available for generating skin substitutes, including both natural biopolymers and synthetic polymers, in terms of tissue response and potential for use in the operating room. Natural biopolymers display an improved cell response, while synthetic polymers provide better control over chemical composition and mechanical properties. It is suggested that not one material meets all the requirements for a skin substitute. Rather, a composite scaffold fabricated from both natural and synthetic biomaterials may allow for the generation of skin substitutes that meet all clinical requirements including a tailored wound size and type, the degree of burn, the patient age, and the available preparation technique. This review aims to be a valuable directory for researchers in the field to find the optimal material or combination of materials based on their specific application.

Gene-activated matrix/bone marrow-derived mesenchymal stem cells constructs regenerate sweat glands-like structure in vivo

It is a significant challenge to regenerate full-thickness skin defects with sweat glands. Various skin substitutes have been developed to resolve this issue with minimal success. In this study, to yield a novel construct for in situ regeneration of sweat glands, the collagen-chitosan porous scaffold was combined with Lipofectamine 2000/pDNA-EGF complexes to obtain the gene-activated scaffold (GAS), which was then seeded with bone marrow-derived mesenchymal stem cells (BM-MSCs). The porous scaffold functionalized as a reservoir for the incorporated gene complexes which were released in a sustained manner. The seeded BM-MSCs were transfected in situ by the released complexes and specially differentiated into sweat gland cells in vitro under the induction of the expressed epidermal growth factor (EGF). Application in vivo of the GAS/BM-MSCs constructs on the full-thickness skin defects of SD rats confirmed that GAS/BM-MSCs could accelerate the wound healing process and induce the in situ regeneration of the full-thickness skin with sweat gland-like structures. Analyzed by immunohistochemical staining, RT-qPCR and Western-blotting, the levels of the major sweat gland markers such as carcino-embryonic antigen (CEA), cytokeratin 8 (CK8) and cytokeratin 14 (CK14) were all up-regulated, indicating that GAS/BM-MSCs can facilitate the regeneration of sweat glands-like structure in vivo.

Methods for Implant Acceptance and Wound Healing: Material Selection and Implant Location Modulate Macrophage and Fibroblast Phenotypes

This review focuses on materials and methods used to induce phenotypic changes in macrophages and fibroblasts. Herein, we give a brief overview on how changes in macrophages and fibroblasts phenotypes are critical biomarkers for identification of implant acceptance, wound healing effectiveness, and are also essential for evaluating the regenerative capabilities of some hybrid strategies that involve the combination of natural and synthetic materials. The different types of cells present during the host response have been extensively studied for evaluating the reaction to different materials and there are varied material approaches towards fabrication of biocompatible substrates. We discuss how natural and synthetic materials have been used to engineer desirable outcomes in lung, heart, liver, skin, and musculoskeletal implants, and how certain properties such as rigidity, surface shape, and porosity play key roles in the progression of the host response. Several fabrication strategies are discussed to control the phenotype of infiltrating macrophages and fibroblasts: decellularization of scaffolds, surface coatings, implant shape, and pore size apart from biochemical signaling pathways that can inhibit or accelerate unfavorable host responses. It is essential to factor all the different design principles and material fabrication criteria for evaluating the choice of implant materials or regenerative therapeutic strategies.

A Clinical Investigation on the Characteristics and Outcomes of Treating Chronic Lower Extremity Wounds using the TissueTech Autograft System

The application of tissue engineering technology to wound healing has resulted in the development of a number of “living skin equivalents.” These have become a viable option in the treatment of chronic, nonhealing wounds. Such wounds present a major cost burden as well as increased morbidity and mortality. Unique among skin tissue engineering technology is the TissueTech autograft system, as it incorporates an autologous dermal substitute—Hyalograft® 3D—and an autologous epidermal replacement, Laserskin® autograft. Each includes a matrix of a hyaluronic acid ester to promote cellular migration and graft take.

Laser processing of polymer constructs from poly(3-hydroxybutyrate)

CO2 laser radiation was used to process poly(3-hydroxybutyrate) constructs - films and 3D pressed plates. Laser processing increased the biocompatibility of unperforated films treated with moderate uniform radiation, as estimated by the number and degree of adhesion of NIH 3T3 mouse fibroblast cells. The biocompatibility of perforated films modified in the pulsed mode did not change significantly. At the same time, pulsed laser processing of the 3D plates produced perforated scaffolds with improved mechanical properties and high biocompatibility with bone marrow-derived multipotent, mesenchymal stem cells, which show great promise for bone regeneration.

Roles of Proteoglycans and Glycosaminoglycans in Wound Healing and Fibrosis

A wound is a type of injury that damages living tissues. In this review, we will be referring mainly to healing responses in the organs including skin and the lungs. Fibrosis is a process of dysregulated extracellular matrix (ECM) production that leads to a dense and functionally abnormal connective tissue compartment (dermis). In tissues such as the skin, the repair of the dermis after wounding requires not only the fibroblasts that produce the ECM molecules, but also the overlying epithelial layer (keratinocytes), the endothelial cells, and smooth muscle cells of the blood vessel and white blood cells such as neutrophils and macrophages, which together orchestrate the cytokine-mediated signaling and paracrine interactions that are required to regulate the proper extent and timing of the repair process. This review will focus on the importance of extracellular molecules in the microenvironment, primarily the proteoglycans and glycosaminoglycan hyaluronan, and their roles in wound healing. First, we will briefly summarize the physiological, cellular, and biochemical elements of wound healing, including the importance of cytokine cross-talk between cell types. Second, we will discuss the role of proteoglycans and hyaluronan in regulating these processes. Finally, approaches that utilize these concepts as potential therapies for fibrosis are discussed.

Silk fibroin/chondroitin sulfate/hyaluronic acid ternary scaffolds for dermal tissue reconstruction

The fabrication of new dermal substitutes providing mechanical support and cellular cues is urgently needed in dermal reconstruction. Silk fibroin (SF)/chondroitin sulfate (CS)/hyaluronic acid (HA) ternary scaffolds (95-248μm in pore diameter, 88-93% in porosity) were prepared by freeze-drying. By the incorporation of CS and HA with the SF solution, the chemical potential and quantity of free water around ice crystals could be controlled to form smaller pores in the SF/CS/HA ternary scaffold main pores and improve scaffold equilibrium swelling. This feature offers benefits for cell adhesion, survival and proliferation. In vivo SF, SF/HA and SF/CS/HA (80/5/15) scaffolds as dermal equivalents were implanted onto dorsal full-thickness wounds of Sprague-Dawley rats to evaluate wound healing. Compared to SF and SF/HA scaffolds, the SF/CS/HA (80/5/15) scaffolds promoted dermis regeneration, related to improved angiogenesis and collagen deposition. Further, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) expression in the SF/CS/HA (80/5/15) groups were investigated by immunohistochemistry to assess the mechanisms involved in the stimulation of secretion of VEGF, PDGF and bFGF and accumulation of these growth factors related to accelerated wound process. These new three-dimensional ternary scaffolds offer potential for dermal tissue regeneration.

Development of perforated microthin poly(ε-caprolactone) films as matrices for membrane tissue engineering

The design and fabrication of thin films based on bioresorbable polymers such as poly(epsilon-caprolactone) (PCL) has been the focus of a part of current biomedical research, especially as matrices for membrane tissue engineering. We have successfully developed perforated microthin PCL membrane for this purpose. Two critical issues are the control of moisture permeability and understanding the degradation of PCL microthin film. In order to increase the moisture permeability. PCL films were biaxially stretched to a thickness of 10 +/- 3 microm and perforated with uniform array of holes (180-275 microm) using a Sony Robotic system. After perforation, the water vapour transmission rate was increased by 50% to a value of 47.6 +/- 2.7 g/h per m2. Accelerated hydrolytic degradations were performed in 5 M NaOH. The degraded samples were characterised for changes in weight, surface morphology, mechanical properties, crystallinity and molecular weight. Hydrolytic degradation commenced with random chain scission of backbone ester bonds on the film surface and followed by loss of material due to surface erosion. In general, the perforated films degraded faster than the unperforated microthin films. Scanning electron microscopic images showed that surface erosion led to extensive formation of micropores, microcracks and increased in surface roughness.

Antibacterial and cell-adhesive polypeptide and poly(ethylene glycol) hydrogel as a potential scaffold for wound healing

The ideal wound-healing scaffold should provide the appropriate physical and mechanical properties to prevent secondary infection, as well as an excellent physiological environment to facilitate cell adhesion, proliferation and/or differentiation. Therefore, we developed a synthetic cell-adhesive polypeptide hydrogel with inherent antibacterial activity. A series of polypeptides, poly(Lys)(x)(Ala)(y) (x+y=100), with varied hydrophobicity via metal-free ring-opening polymerization of NCA-Lys(Boc) and NCA-Ala monomers (NCA=N-carboxylic anhydride) mediated by hexamethyldisilazane (HMDS) were synthesized. These polypeptides were cross-linked with 6-arm polyethylene glycol (PEG)-amide succinimidyl glutarate (ASG) (M(w)=10K) to form hydrogels with a gelation time of five minutes and a storage modulus (G') of 1400-3000 Pa as characterized by rheometry. The hydrogel formed by cross-linking of poly(Lys)(60)(Ala)(40) (5 wt.%) and 6-arm PEG-ASG (16 wt.%) (Gel-III) exhibited cell adhesion and cell proliferation activities superior to other polypeptide hydrogels. In addition, Gel-III displays significant antibacterial activity against Escherichia coli JM109 and Staphylococcus aureus ATCC25923. Thus, we have developed a novel, cell-adhesive hydrogel with inherent antibacterial activity as a potential scaffold for cutaneous wound healing.

Bioengineered skin in diabetic foot ulcers

OBJECTIVE

Bioengineered skin (BS) has been shown to play an important role in the treatment of diabetic foot ulcers (DFUs). Whether BS in the therapy of DFU can improve the outcomes still remains uncertain. We performed a quantitative meta-analysis of available randomized controlled trials to determine the effectiveness and safety of BS in the treatment of patients with DFUs.

DESIGN AND METHODS

Comprehensive search strategies of various electronic databases were used for this study to evaluate the effectiveness and safety between BS and conventional treatment (CT) in patients with DFU, and only randomized controlled trials were adopted in our review. Search terms included 'bioengineered skin', 'tissue-engineering skin', 'human-tissue graft', 'human-skin device', 'living-skin equivalent' and 'diabetic foot', 'diabetic ulcer', 'diabetic wound'. Analysis outcomes included complete wound closure, complications, ulcer recurrence and adverse severe events (ASEs).

RESULTS

Seven randomized controlled trials on BS vs. CT were included, and 880 participants met inclusion criteria. Pooled analysis showed a significant effectiveness and safety advantages for BS treatment compared to CT for patients with DFUs. In analysis of complications, only statistically significant difference of infection was noted. And no included trials reported ASEs related to these treatments.

CONCLUSIONS

Based on the meta-analysis, patients with DFUs may benefit from the BS because of its high effectiveness and safety and reduced risk for infections in comparison to CT.

Bioartificial Organ Grafts: A View at the Beginning of the Third Millennium

An immunoisolated collection of cells, which communicate and exchange essential factors, co-stimulatory hormones, as well as providing immunoprotection and immunomodulation, can be prepared, given existing scientific and medical know-how, within two decades. These "Bioartificial Organ Grafts" have advantages relative to isolated cell therapies, including beta-cell encapsulation for diabetes treatment, and xenotransplantation, which has a de facto moratorium. This paper documents that the majority of the research for the bioartificial organ grafts has been concluded, with the remaining hurdles minimum in comparison. The use of co-encapsulation and the induction of local immune-privilege will provide a more sensitive humoral hormonal response and graft survival, without systemic immunosuppression. A call for the staged implementation of bioartificial organ grafts, based on the best available medical practice, materials, tissue and technology available, is advocated. The implementation of bioartificial organ grafts can begin within the next two years, based on allografts succeeded by genetically modified human tissue, without the need to pass through a xenograft stage.

[Skin replacement with biological and biosynthetic materials following burn injury]

Autotransplantation is currently regarded as the optimal skin replacement method, sufficient donor site, however, is often not available in extensively burned patients. Intensive research and development of skin replacement products is conducted worldwide in order to decrease the size of the required donor site. Short- and long-term wound coverage is made possible by temporary synthetic and non-synthetic skin substitutes. Autografts and cultured epithelial autografts are used for permanent skin substitution. Until this is possible, the barrier function of the skin is provided by bio-engineered temporary skin substitutes. Some products and methods are currently available in Hungary, while others are still in the introductory phase. In order to provide an overview, authors summarize the skin replacement methods and compare the different skin replacement products used worldwide from the perspective of the burn surgeon. The use of new methods to be introduced in the near future needs to be rationalized due to financial considerations.

Morphological characteristics and proliferation of keratocytes cultured under simulated microgravity

This study probed the changes of keratocytes cultured under simulated microgravity. Keratocytes were isolated from rabbit corneas using collagenase digestion method. Cells were seeded in a 55-mL capacity high-aspect-ratio vessel (HARV) of rotary cell culture system (RCCS) at a density of 1 x 10(4) cells/mL. Dehydrated bovine acellular corneal stroma (5 x 5 x 1 mm, n = 30) was used as a carrier for keratocyte culture. Rotational speed was set at 15, 20, and 30 rpm in the first, second, and third week of culture, respectively. Histological evaluation showed that keratocytes in simulated microgravity culture grew into carriers, but those under conventional gravity grew on the surface of carriers. Scanning electron microscopic evaluation showed that after 19 days in culture, keratocytes on the carriers were spherical and spread in the spaces among the collagen fibers. Cells were dendritic or spindle shaped, and they developed many foot processes linked with surrounding cells. The absorbance values of the simulated microgravity group were significantly higher (P < 0.01) than that of the conventional group from 10 to 19 days of culture. The RCCS obviously enhanced the proliferation of rabbit keratocytes and facilitated the cells' growth into or on the dehydrated bovine acellular corneal stroma. Cells showed more natural morphology.

Hyaluronic acid: the scientific and clinical evidence

Hyaluronic acid is a naturally occurring biopolymer whose molecular structure is highly conserved between mammalian species. First described in 1934, it has since been used across a wide variety of medical fields as diverse as neurosurgery and cutaneous wound healing. Presently it has reached prominence in cosmetic practice where it is now the injectable dermal filler of choice for most surgeons. We used our experience of this technology with searches in the English language literature for the purpose of a systematic review. We present an overview, including the scientific evidence for its use in wound healing and, briefly, in other fields. We summarise the evidence for and against hyaluronic acid and provide a resumé of the current technologies available in fields such as skin regeneration and wound healing, in addition to cosmetic surgery. This overview is not intended to teach the reader about the various formulations currently on the market or how to use these materials clinically - rather to provide a solid scientific background enabling the reader to understand the attributes (and otherwise) of the material. We hope to allow clinicians to assess the evidence for a material now in common use in order that they may be fully aware of its properties.

The role of hyaluronic acid in wound healing: assessment of clinical evidence

Hyaluronic acid (hyaluronan), a naturally occurring polymer within the skin, has been extensively studied since its discovery in 1934. It has been used in a wide range of medical fields as diverse as orthopedics and cosmetic surgery, but it is in tissue engineering that it has been primarily advanced for treatment. The breakdown products of this large macromolecule have a range of properties that lend it specifically to this setting and also to the field of wound healing. It is non-antigenic and may be manufactured in a number of forms, ranging from gels to sheets of solid material through to lightly woven meshes. Epidermal engraftment is superior to most of the available biotechnologies and, as such, the material shows great promise in both animal and clinical studies of tissue engineering. Ongoing work centers around the ability of the molecule to enhance angiogenesis and the conversion of chronic wounds into acute wounds.

Laser surface modification of poly(epsilon-caprolactone) (PCL) membrane for tissue engineering applications

Ultra-thin polycaprolactone (PCL) produced by bi-axial stretching was previously shown to have significant advantage for membrane tissue engineering. However, the permeability of the membrane needs to be enhanced. In this study, ablation experiments using femtosecond laser and excimer laser were carried out to modify the PCL surface. The use of the femtosecond laser produces neat drilled-through holes while the excimer laser is employed to produce blind-holes on the membrane. The modified surface of the membrane was studied and analyzed for different laser parameters (such as pulse energy and pulse repetition rate and characterized using several techniques that include optical microscopy, scanning electron microscopy and water contact angle measurements). Results showed that the morphological surface changes with different laser parameters, and the water contact angle decreases as the surface of the membrane is modified. The decrease in water contact angle suggests that surface of the membrane had become more hydrophilic than the non-laser treated membrane. The present study demonstrated that laser surface modification on the PCL can be achieved with high degree of success and precision. This paved the way for further enhancement in membrane tissue engineering.

[Autologous cultured skin substitutes]

Progress in cell culture and biomaterial technologies has resulted in commercially available autologous and allogeneic skin substitutes that are composed of keratinocytes and/or fibroblats, in part combined with allogeneic (fibrin) or xenogeneic (collagen, hyaluronan) matrix substances. So far, clinical testing of tissue-engineered products focused on chronic wounds (vascular leg ulcers, diabetic foot ulcers); another major indication, however, is large acute skin defects (burns). During the last decade, partly-controlled clinical trials have been performed with several cultured skin substitutes, studying primarily vascular leg ulcers; a few of these products have been approved for defined indications by the regulatory authorities of various countries. To fulfill regulatory requirements and be eligible for reimbursement, safety as well as cost-effectiveness have to be documented for these novel therapies in contrast to established methods for clearly defined clinical settings; this, in combination with restricted health care resources, is actually hampering the clinical breakthrough of tissue engineering in the treatment of skin wounds, despite undiminished research activities.

Clinical applications of tissue engineered constructs

The reconstruction of soft tissue defects poses a challenge for plastic surgeons and tissue engineers. The construction of a biologically, functionally, and cosmetically successful replacement part will involve the combination of a composite that contains endoderm, mesoderm, and ectoderm. It will be active in immune surveillance and function. It must be durable to withstand the stress and strain encountered by the skin. Such a composite will involve the use of bone, cartilage, muscle, blood vessels, nerves, connective tissue, dermis, and epidermis. Fortunately, many of these tissues are among the best studied by tissue engineers. The future of this field will likely involve to some degree the co-mingling of current reconstructive modalities, including the techniques of prefabrication and pre-lamination, with more aggressive and successful tissue engineering technology and the rapidly developing science of stem cell biology. Tissues synthesized in vitro with better structure, color, and texture can be pre-laminated to a site that has already been prefabricated. Prefabrication of a bio-absorbable matrix can create a well perfused scaffold onto which larger subunits can be prelaminated. The future of this field of endeavor is exciting, and, with further research, experience, and interdisciplinary collaboration, bioengineered tissue constructs will become a reality.

HYAFF 11-based autologous dermal and epidermal grafts in the treatment of noninfected diabetic plantar and dorsal foot ulcers: a prospective, multicenter, controlled, randomized clinical trial

OBJECTIVE

To evaluate the clinical efficacy and safety of HYAFF 11-based autologous dermal and epidermal grafts in the management of diabetic foot ulcers.

RESEARCH DESIGN AND METHODS

A total of 79 patients with diabetic dorsal (n = 37) or plantar (n = 42) ulcers were randomized to either the control group with nonadherent paraffin gauze (n = 36) or the treatment group with autologous tissue-engineered grafts (n = 43). Weekly assessment, aggressive debridement, wound infection control, and adequate pressure relief (fiberglass off-loading cast for plantar ulcers) were provided in both groups. Complete wound healing was assessed within 11 weeks. Safety was monitored by adverse events.

RESULTS

Complete ulcer healing was achieved in 65.3% of the treatment group and 49.6% of the control group (P = 0.191). The Kaplan-Meier mean time to closure was 57 and 77 days, respectively, for the treatment versus control groups. Plantar foot ulcer healing was 55% and 50% in the treatment and control groups, respectively. Dorsal foot ulcer healing was significantly different, with 67% in the treatment group and 31% in the control group (P = 0.049). The mean healing time in the dorsal treatment group was 63 days, and the odds ratio for dorsal ulcer healing compared with the control group was 4.44 (P = 0.037). Adverse events were equally distributed between the two groups, and none were related to the treatments.

CONCLUSIONS

The autologous tissue-engineered treatment exhibited improved healing in dorsal ulcers when compared with the current standard dressing. For plantar ulcers, the off-loading cast was presumably paramount and masked or nullified the effects of the autologous wound treatment. This treatment, however, may be useful in patients for whom the total off-loading cast is not recommended and only a less effective off-loading device can be applied.

Complementation of the DNA repair deficiency in human xeroderma pigmentosum group a and C cells by recombinant adenovirus-mediated gene transfer

Nucleotide excision repair (NER) is one of the most versatile DNA repair mechanisms, ensuring the proper functioning and trustworthy transmission of genetic information in all living cells. The phenotypic consequences caused by NER defects in humans are autosomal recessive diseases such as xeroderma pigmentosum (XP). This syndrome is the most sun-sensitive disorder leading to a high frequency of skin cancer. The majority of patients with XP carry mutations in the XPA or XPC genes that encode proteins involved in recognition of DNA damage induced by UV light at the beginning of the NER process. Cells cultured from XPA and XPC patients are hypersensitive to UV light, as a result of malfunctioning DNA repair. So far there is no effective long-term treatment for these patients. Skin cancer prevention can only be achieved by strict avoidance of sunlight exposure or by the use of sunscreen agents. We have constructed recombinant adenoviruses carrying the XPA and XPC genes that were used to infect XP-A and XP-C immortalized and primary fibroblast cell lines. UV survival curves and unscheduled DNA synthesis confirmed complete phenotypic reversion in XP DNA repair deficient cells with no trace of cytotoxicity. Moreover, transgene expression is stable for at least 60 days after infection. This efficient adenovirus gene delivery approach may be an important tool to better understand XP deficiency and the causes of DNA damage induced skin cancer.