Dermal Regeneration Template in the Management and Reconstruction of Burn Injuries and Complex Wounds: A Review.

Background: Dermal scaffolds have created a paradigm shift for burn and wound management by providing improved healing and less scarring, while improving cosmesis and functionality. Dermal regeneration template (DRT) is a bilayer membrane for dermal regeneration developed by Yannas and Burke in the 1980s. The aim of this review is to summarize clinical evidence for dermal scaffolds focusing on DRT for the management and reconstruction of burn injuries and complex wounds. Methods: A comprehensive search of PubMed was performed from the start of indexing through November 2022. Articles reporting on DRT use in patients with burns, limb salvage, and wound reconstruction were included with focus on high-level clinical evidence. Results: DRT has become an established alternative option for the treatment of full-thickness and deep partial-thickness burns, with improved outcomes in areas where cosmesis and functionality are important. In the management of diabetic foot ulcers, use of DRT is associated with high rates of complete wound healing with a low risk of adverse outcomes. DRT has been successfully used in traumatic and surgical wounds, showing particular benefit in deep wounds and in the reconstruction of numerous anatomical sites. Conclusions: Considerable clinical experience has accrued with the use of DRT beyond its original application for thermal injury. A growing body of evidence from clinical studies reports the successful use of DRT to improve clinical outcomes and quality of life across clinical indications at a number of anatomical sites.

Mesenchymal Stem Cells and Regenerative Therapy with Bilateral Gracilis Flaps for Perineal Reconstruction of a Wound Infection in the Setting of Anal Squamous Cell Carcinoma.

ABSTRACT: Many patients are affected by HIV/AIDS, and these conditions are highly prevalent worldwide. Patients with HIV/AIDS can experience debilitating wound infections that often require flap reconstruction and become challenging for surgeons to treat. In the past 5 years, mesenchymal stem cells have been tested and used as regenerative therapy to promote the growth of tissues throughout the body because of their ability to successfully promote cellular mitogenesis. To the authors' knowledge, the use of mesenchymal stem cell grafting following necrosis of a myocutaneous gracilis flap (as part of perineal wound reconstruction) has never been reported in the literature.In addition, the use of mesenchymal stem cells and regenerative medicine combined in the setting of squamous cell carcinoma of the anus with prior radiation (along with comorbid AIDS) has not been previously documented.In this report, the authors outline the case of a 60-year-old patient who had a recipient bed (perineum) complication from prior radiation therapy. Complicating the clinical picture, the patient also developed a Pseudomonal organ space infection of the pelvis leading to the failure of a vertical rectus abdominis myocutaneous flap and myocutaneous gracilis flaps. As a result, the patient underwent serial operative debridements for source control, with the application of mesenchymal stem cells, fetal bovine dermis, porcine urinary bladder xenograft, and other regenerative medicine products, achieving a highly successful clinical outcome. A procedural description for future use and replication of this method is provided.

Integra® Dermal Regeneration Template: From Design to Clinical Use.

Integra® Dermal Regeneration Template (IDRT, Integra LifeSciences, Princeton, NJ, USA) is a bilayer membrane developed, by Yannas and Burke in the 1980s, to fulfill the unmet need of surgeons having a readily available off-the-shelf dermal regeneration method. IDRT is composed of a sheet of porous cross-linked type I collagen and glycosaminoglycans, with a semi-permeable silicone sheet cover. IDRT is bio-engineered, from adult bovine Achilles tendons and chondroitin-6-sulfate derived from shark cartilage, in a multi-step process involving cross-linking using glutaraldehyde. By design, the composition, porosity, and biodegradation rate of IDRT guides the mechanism of wound repair towards a regenerative pathway. Its mechanism of action involves four distinct phases: imbibition, fibroblast migration, neovascularization, and remodeling/maturation. Originally developed for the post-excisional treatment of deep-partial to full-thickness burns where autograft is limited, over the years its use has expanded to reconstructive surgery.

Use of collagen-glycosaminoglycan silicone bilayer matrix for closure of post-Mohs micrographic surgery defects on the nose: a 5-case series.

INTRODUCTION: The use of dermal matrices has shown to be reliable and less invasive than skin grafts or skin flaps for wound management. This case series reports the clinical outcomes of 5 patients with defects on the nose post-MMS managed using collagen-glycosaminoglycan silicone bilayer matrix. MATERIALS AND METHODS: Patient 1 had a BCC of the left nasal lateral sidewall, patient 2 had a BCC of the right nasal ala, patient 3 had a BCC of the nasal dorsum, patient 4 had a BCC of the left medial canthus, and patient 5 had a BCC of the left alar lobule of the nose. Layers of dermal matrix were stacked to augment soft tissue coverage in patient 5. RESULTS: All patients had spontaneous epithelialization of the nose defects following dermal matrix placement. Time to healing ranged from 4 to 11 weeks after dermal matrix placement for defects ranging from 1.44 cm2 to 6.16 cm2. The covering was stable and resulted in satisfactory cosmesis at time of complete epithelialization. CONCLUSIONS: Closure of post-MMS nasal defects using bilayer matrix represents a viable option and an advantage over alternative forms of surgical repair when considering cosmesis and patient satisfaction.

Serial application of meshed collagen-chondroitin silicone bilayer matrix to obtain full coverage over bone and tendon in challenging situations and medically compromised patients: a small case series.

INTRODUCTION: Soft tissue defects in medically compromised patients present significant challenges to the reconstructive surgeon, particularly when vital structures are exposed. This case series reports clinical outcomes of 5 adult patients with challenging medical problems whose wounds were managed using a meshed collagen-chondroitin silicone bilayer matrix to obtain coverage over bone and tendon. MATERIALS AND METHODS: Patient 1 had significant degloving of the scalp. Patient 2, who had a giant neglected tumor, had a defect comprising the entire occipital skull. Patients 3 and 4 had necrotizing infection in a lower extremity open wound and a pretibial wound (patient 3). Patient 5 sustained a severe crush injury of his forearm and had a large open wound. All the wounds had exposed structures. RESULTS: The incorporation rate of the dermal matrix in the wound bed was 100% in patients 1 and 5, 75% in patient 2, and 90% in patients 3 and 4. Patients 2 and 4 received a second application of dermal matrix to obtain full coverage of the wounds. Each patient achieved stable soft tissue coverage and successful reconstruction. CONCLUSIONS: These 5 cases highlight the capacity and capability of this dermal matrix to allow coverage over exposed bone and tendon, as well as the clinical utility of the serial application of this matrix.

Negative pressure wound therapy on complex extremity wounds requiring coverage with a meshed bilayer wound matrix: a retrospective analysis.

OBJECTIVE: The treatment of complex extremity wounds is technically challenging. In this 5-year retrospective review, we compared the use of Integra Meshed Bilayer Wound Matrix (IMBWM; Integra LifeSciences, US) followed by a split-thickness skin graft (STSG) combined with negative pressure wound therapy (NPWT) versus IMBWM followed by STSG alone for the management of these wounds. METHOD: Data from patients undergoing management using IMBWM for a complex extremity wound coverage were collected. RESULTS: Among the 109 patients studied, the wounds of 62 patients were managed using IMBWM and NPWT, and 47 were managed using IMBWM alone. The most common aetiology of these injuries was trauma. Wound size and location were similar for each group, ranging in size from 2-30cm2 and being primarily on the forearm, followed by the leg and arm. There was a significantly greater take of the IMBWM+STSG with NPWT (96.8%) compared to without NPWT (85.1%, p=0.03). There were significantly fewer reapplications of the dermal matrix required in the NPWT group (3.2%) versus the non-NPWT group (14.9%, p=0.03). There were significantly fewer postoperative complications, prior to STSG, in the NPWT group (3.2%) versus the non-NPWT group (14.9%, p=0.03). CONCLUSION: The combination of IMBWM with NPWT leads to a higher success rate, and can reduce the number of dermal matrix reapplications and postoperative complications, in the setting of complex extremity wounds. The use of IMBWM in combination with NPWT has the potential to improve both surgical procedures and patient outcomes in this setting.

Integra Dermal Regeneration Template in reconstructive surgery for cutaneous tumours: a two-year retrospective review.

OBJECTIVE: Integra Dermal Regeneration Template (IDRT) (Integra LifeSciences, US) is a bioengineered dermal matrix that has been widely used in burn reconstruction since its first description. However, little is reported on its use in oncologic dermatological defects. Our objective was to evaluate reconstruction using IDRT on cutaneous tumour defects. METHOD: We conducted a two-year retrospective review of patients with skin tumours who had an excision surgery, followed by reconstruction with IDRT, as a mid-step towards a final autograft procedure: a split-thickness skin graft. The records of all patients at a single academic institution were queried from the electronic medical record using data obtained from the operating surgeon. RESULTS: We identified 13 patients with different tumour types and locations. The mean defect size was 105.92cm². The matrix take rate was 92.3% and average postoperative day for definite autograft was 20 days. Patients were followed for a period of up to 12 months. Of the patients, one had exposed bone without periosteum; another patient showed recurrence six months after matrix placement, requiring a new second two-stage IDRT-autograft procedure before radiation therapy. Patients reported complete satisfaction with the cosmetic, functional and oncological results. No cases of infection were encountered. CONCLUSION: IDRT is a valid option for the reconstruction of oncologic surgical defects of the skin and can be used in different anatomical locations. Specifically, it is an alternative to the reconstructive ladder when grafts and local flaps are not possible in those patients, and an option for patients who will eventually need adjuvant radiotherapy.

Single-stage extremity reconstruction through the use of dermal matrices: the power of Integra® bilayer wound matrix in the face of medical comorbidities, patient preference and non-compliance.

We report 4 cases of extremity reconstruction using Bilayer Wound Matrix with plan to perform two-stage procedures. Patient preference or non-compliance led to single-stage reconstruction with wound re-epithelialization. In this setting, dermal matrices may be used as single-stage stand alone wound reconstruction procedures, even in patients with comorbid conditions. Ajul Shah is a consultant of Integra LifeSciences Corporation Philippe Taupin is an employee of Integra LifeSciences Corporation.

Strategies for extremity reconstruction with exposed bones and tendons using acellular dermal matrices: concept of sequential vascularization.

We report 3 cases of patients treated with Bilayer Wound Matrix over exposed structures. In all patients, dermal matrices revascularization occurred sequentially over the course of 6-12 weeks, leading to successful wound closure. Acellular dermal matrices allow more difficult areas with poor vascularity to be covered from the 'inside-out'.

Modulation of GDP-fucose level for generating proteins with reduced rate of fucosylation (WO2010141855).

BACKGROUND: The application (WO2010141855) is in the field of glycobiology, and involves the control of the rate of fucosylation of proteins by exogenous factors. OBJECTIVE: It aims at controlling the rate of protein fucosylation with inhibitors (drugs or nucleic acid antagonists) of enzymes involved in the synthesis of GDP-fucose. METHODS: Mammalian cell lines were cultured in the presence of inhibitors, for example, siRNA. The rates of GDP-fucose in cells and during protein fucosylation were characterized. RESULTS: The level of protein fucosylation decreases rapidly in response to a decrease in GDP-fucose level. CONCLUSION: The relationship between the rate of fucosylation of proteins and the level of GDP-fucose in a cell is non-linear. Reduction in the rate of protein fucosylation can be achieved with a minimal reduction of the level of GDP-fucose in cells. The paradigm may be used to synthesize proteins and antibodies, with a reduced rate of fucosylation. The application claims that the use of drugs or nucleic acid antagonists that inhibit the enzymes involved in GDP-fucose biosynthesis optimizes the level of GDP-fucose present in cells, and reduces the rate of fucosylation of glycoproteins.

Parthenogenetically activated human oocytes and parthenogenetic embryonic stem cells: US20100233143.

BACKGROUND: The application (US20100233143) is in the field of embryonic stems cells (ESCs) and the generation of ESCs from parthenogenetically activated human oocytes. OBJECTIVE: It aims at determining optimal conditions for parthenogenetically activating human oocytes. METHODS: Oocytes isolated from female donors were activated in vitro in the presence of an ionophore at high oxygen (O(2)) tension and by a serine-threonine kinase inhibitor under low O(2) tension. The blastocysts were transferred to a feeder layer, and the inner cell masses (ICMs) were mechanically isolated. RESULTS: Human ESCs were derived from the ICMs of the parthenogenetically activated oocytes. CONCLUSION: Parthenogenetic ESCs (pESCs) provide a model for cellular therapy and regenerative medicine. The paradigm may be used for generating isogenic cells lines relative to the donors. The application claims the method for parthenogenetically activating human oocytes, including cryopreserved oocytes or parthenotes, and for generating pESC lines for therapy and drug discovery. The application further claims the establishment of a cell bank of human pESCs.

Cell lines expressing mutant FX proteins to generate proteins with reduced rate of fucosylation: WO2010/141478.

BACKGROUND: The application (WO 2010/141478) is in the field of glycobiology and deals with the synthesis of recombinant proteins with a reduced rate of fucosylation. OBJECTIVE: It aims at generating mammalian cell lines that express mutant forms of GDP-4-keto-deoxy-mannose-3,5,-epimerase-4-reductase (FX) and cells that conditionally fucosylate proteins. METHODS: Mutant forms of FX were synthesized, and mammalian cell lines genetically engineered to express mutant FX proteins and the protein of interest. Cell lines that conditionally fucosylate proteins were generated from a mutant FX form that has reduced ability to fucosylate glycoproteins at 37°C and not at 34°C. RESULTS: Cells genetically engineered to express mutant forms of FX protein show reduced ability to fucosylate proteins, particularly antibodies, with rates as low as 5 - 0.5% fucosylation, compared to cells expressing wild-type FX. CONCLUSION: Cells genetically engineered to express the mutant forms of FX protein provide a means to synthesize and express proteins with a reduced rate of fucosylation. The paradigm may be used to synthesize antibodies that mediate antibody-dependent cell-mediated cytotoxicity more efficiently. The application uses mammalian cell lines, genetically engineered to express mutant FX proteins, to synthesize and produce proteins with a reduced rate of fucosylation. The application claims the conditional control of protein fucosylation by FX mutant proteins.

Chimeric proteins comprising the constant region of immunoglobulins for treating hemophilia B (WO2005001025).

The application (WO2005001025) details recombinant fusion proteins attached to the constant region of heavy chains of immunoglobulins. They are found to be particularly useful for the treatment of hemostatic disorders, such as hemophilia B. It aims at engineering chimeric proteins comprising of a single molecule of human factor IX (FIX) and the constant region (Fc domain) of one or two heavy chain(s) of human IgG (rFIXFc). cDNA for rFIXFc was generated by a PCR. rFIXFc protein was isolated and purified from stably transfected mammalian cells. The concentration and clotting activity of rFIXFc were assessed in mice, rats, monkeys, and FIX-deficient mice and dogs, after intravenous administration. The half-life of rFIXFc activity is prolonged by three to fourfold, compared with rFIX, when administered intravenously in all animals. The generation of chimeric proteins, comprised of FIX fused to the Fc domain of IgG, extends the clotting activity of the recombinant molecule. rFIXFc represents a promising candidate for the treatment of patients with hemophilia B. The application claims the methods of making recombinant chimeric proteins comprising of one biologically active molecule fused to the Fc region of the heavy chain(s) of immunoglobulins and their use for therapy.

Neurogenic drugs and compounds to treat CNS diseases and disorders.

Neurological diseases and related conditions affect an estimated 1 billion of individuals worldwide [1]. There is still no cure for neurological diseases and disorders, barely a few treatments more or less efficient. This mandates the design and development of novel paradigms and strategies, to discover and develop new treatments and cures for these diseases. Neurogenesis occurs in the adult brain of mammals primarily in two regions, the dentate gyrus (DG) of the hippocampus and the subventricular zone, in various species including in humans. Neural progenitor and stem cells have been isolated, propagated and characterized in vitro from the adult brain of mammals, including humans. The confirmation that neurogenesis occurs in the adult brain and neural stem cells (NSCs) reside in the adult central nervous system (CNS) of mammals, opens new avenues and opportunities for treating neurological diseases and injuries [2].

Neurogenesis, NSCs, pathogenesis and therapies for Alzheimer's disease.

Neurogenesis occurs in the adult brain and neural stem cells (NSCs) reside in the adult central nervous system (CNS) of mammals. Adult NSCs offer tremendous potential for cellular therapy for the treatment of neurological diseases and injuries, particularly of Alzheimer's disease (AD). The contribution of newly generated neuronal cells of the adult brain to the functioning of the nervous system remains to be elucidated. Neurogenesis is enhanced in the brain of patients with AD. Enhanced neurogenesis would contribute to regenerative attempts in AD, to compensate for the neuronal loss. Adult neurogenesis holds the potential to generate aneuploid cells, a landmark of AD pathology. Aneuploid newly generated neuronal cells in the adult brain would contribute to the pathogenesis of AD. Adult neurogenesis would not only be beneficial, but also detrimental for patients with AD. We will review and discuss the potential of adult NSCs for the treatment of AD and their contribution to the pathogenesis of the disease, as well as the development of novel drugs and therapies for treating AD.

Antibodies against CD20 (rituximab) for treating multiple sclerosis: US20100233121.

BACKGROUND: The application is in the field of medication and treatment for MS. OBJECTIVE: It aims at identifying and characterizing the activity and potency of antibodies against CD20 (rituximab) for treating MS and at devising treatments and dosing protocols for various forms of MS. METHODS: Various doses of antibody and different time points were assessed to devise treatments and dosing protocols for MS. RESULTS: Rituximab depletes peripheral B cells and reduces the level of B cells in the cerebrospinal fluid of patients with relapsing-remitting MS. Various treatments and dosing protocols are proposed for improving the signs, symptoms or other indicators of patients with relapsing-remitting MS and with primary progressive MS. CONCLUSION: Antibodies against CD20 and rituximab offer new opportunities to treat patients with MS. The application claims the use of antibodies against CD20 and rituximab for treating the various forms of MS. The application claims the administration of the antibodies at separate intervals, and alone or in combination with other drugs and treatments. It claims a manufacture product for the medication. It further claims the administration of antibodies against CD20 by gene therapy for treating MS.

Thirteen compounds promoting oligodendrocyte progenitor cell differentiation and remyelination for treating multiple sclerosis: WO2010054307.

BACKGROUND: The application is in the field of cellular therapy and neural repair. OBJECTIVE: It aims at identifying and characterizing compounds and molecules that promote the differentiation of oligodendrocyte progenitor cells and remyelination of the nervous system. METHODS: Library of compounds and molecules were screened on a series of assays specifically designed and developed to assess the activity and potency of compounds and molecules on the differentiation of oligodendrocyte progenitor cells and on remyelination of nerve cells in in vitro and in vivo models, such as cultures of neural progenitor and stem cells, cerebellar organotypic cultures, the zebrafish and the cuprizone-mediated demyelination mouse models. RESULTS: In all, 13 compounds were identified and characterized, after a secondary screening, for inducing the differentiation of oligodendrocyte progenitor cells and for promoting myelination and remyelination in vitro and in vivo. CONCLUSION: The 13 compounds, promoting the differentiation of oligodendrocyte progenitor cells and myelination of nerve cells, may be used for the treatment of multiple sclerosis (MS) and other myelin-related disorders. The application claims the use of the compounds to promote the differentiation of oligodendrocyte progenitor cells and endogenous remyelination for the treatment of demyelinating diseases alone or in combination with other agents and drugs, such as immunomodulatory, immunosuppressive, neuroprotective and neuroregenerative agents.

Neurogenic drugs and compounds.

The advent of adult neurogenesis and neural stem cell (NSC) research opens new avenues and opportunities for treating neurological diseases and disorders, particularly for the discovery and development of novel drugs. Adult neurogenesis is modulated by a broad range of stimuli, physio- and pathological processes, trophic factors/cytokines and drugs, particularly drugs used for treating neurological diseases and disorders. Hence, adult neurogenesis is the target of drugs used for treating neurological diseases and disorders, such as Alzheimer's disease and depression, and the activities of neurological drugs may be mediated by adult NSCs. Although the contribution and mechanism of adult neurogenesis and newly generated neuronal cells of the adult brain in the activities of neurological drugs remain to be determined, new research is geared toward discovering and developing novel drugs that target specifically adult neurogenesis and the NSCs of the adult brain. Neurogenic drugs may reverse or compensate deficits and impairments associated with neurological diseases and disorders, particularly those associated with the hippocampus. They may have a potential for regenerative medicine and for the treatment of brain tumors. However, limitations in established models and protocols currently used in the drug discovery and development process of these drugs may hinder their potency and specificity. Here, we reviewed and discussed recent patents on neurogenic drugs and compounds, particularly nootropic agents and apigenin and related compounds.

Very small embryonic-like stem cells for regenerative medicine: WO2010039241.

BACKGROUND: The application is in the field of stem cells and regenerative medicine. OBJECTIVE: It aims at identifying and characterising a population of pluripotent stem cells present in adult tissues. METHODS: Cells were isolated and purified using Fluorescence-Activated Cell Sorting and Direct ImageStream analysis from various adult and umbilical cord tissues of rodents and humans. Cells were propagated in the presence of trophic factors and feeder cell layers of C2C12 cells. Cells were characterised by electron microscopy and immunocytology. RESULTS: A population of cells that do not express a panleukocytic antigen CD45 and are negative for other markers of haematopoietic lineages were isolated and purified. The isolated cells elicit morphological features of embryonic stem cells (ESCs). They express markers of pluripotent stem cells, such as Nanog, Oct-4 and SSEA-1. On culturing on feeder cell layers, the isolated and purified cells generate embryoid body-like sphere. CONCLUSION: The identified and characterised cells elicit features of pluripotent stem cells and similarities with ESCs. They are termed very small embryonic-like stem cells (VSELs). The application claims the use of VSELs for cellular therapy and regenerative medicine.

Ex vivo fucosylation of stem cells to improve engraftment: WO2004094619.

BACKGROUND: The application is in the field of haematopoietic stem cell (HSC) and umbilical cord blood (CB) transplantation. OBJECTIVE: It aims at determining an enzymatic procedure to improve the engraftment of CB stem cells to the bone marrow (BM) as well as the rate of success of CB transplantation. METHODS: Human CB stem cells were treated with alpha1-3 fucosyltransferase VI (FTVI) for 30 min ex vivo prior to transplantation. Human CB stem cells were administered intravenously in irradiated nonobese diabetic/severe combined immune deficiency (NOD/SCID) mice. RESULTS: Treatment of CB stem cells with FTVI improves their engraftment in the BM of NOD/SCID mice. CONCLUSION: Treatment of CB stem cells with FTVI, ex vivo prior to transplantation, may reduce the delay of engraftment of CB stem cells to the BM and the risk of early infections associated with CB transplants, particularly in adults. It may improve the outcome and rate of success of CB transplantation. The application claims the use of fucosyltransferase for improving the engraftment of CB HSCs to the BM for the treatment of haematologic diseases. The procedure may be used to improve the engraftment of HSCs from other sources and other types of stem cells, on transplantation, particularly when administered intravenously.