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.

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.

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.

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.

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.

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.

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'.

Expression and function of orphan nuclear receptor TLX in adult neural stem cells.

The finding of neurogenesis in the adult brain led to the discovery of adult neural stem cells. TLX was initially identified as an orphan nuclear receptor expressed in vertebrate forebrains and is highly expressed in the adult brain. The brains of TLX-null mice have been reported to have no obvious defects during embryogenesis; however, mature mice suffer from retinopathies, severe limbic defects, aggressiveness, reduced copulation and progressively violent behaviour. Here we show that TLX maintains adult neural stem cells in an undifferentiated, proliferative state. We show that TLX-expressing cells isolated by fluorescence-activated cell sorting (FACS) from adult brains can proliferate, self-renew and differentiate into all neural cell types in vitro. By contrast, TLX-null cells isolated from adult mutant brains fail to proliferate. Reintroducing TLX into FACS-sorted TLX-null cells rescues their ability to proliferate and to self-renew. In vivo, TLX mutant mice show a loss of cell proliferation and reduced labelling of nestin in neurogenic areas in the adult brain. TLX can silence glia-specific expression of the astrocyte marker GFAP in neural stem cells, suggesting that transcriptional repression may be crucial in maintaining the undifferentiated state of these cells.

Adult neurogenesis, neuroinflammation and therapeutic potential of adult neural stem cells.

The pathogenesis of neurological diseases and disorders remains mostly unknown. Neuroinflammation has been proposed as a causative factor for neurological diseases. The confirmation that neurogenesis occurs in the adult brain and neural stem cells (NSCs) reside in the adult central nervous system (CNS) of mammals has tremendous implications for our understanding of the physio- and pathology of the nervous system. The generation of newborn neuronal cells in the adult brain is modulated in neurological diseases and during inflammation. This suggests that adult neurogenesis is involved in the pathogenesis of neurological diseases and disorders, particularly during neuroinflammation. In this manuscript, we will review the modulation of adult neurogenesis in neurological diseases and during neuroinflammation. We will discuss the role and contribution of neuroinflammation and adult neurogenesis to neurological diseases and disorders, and for the therapeutic potential of adult NSCs.

Processing scarce biological samples for light and transmission electron microscopy.

Light microscopy (LM) and transmission electron microscopy (TEM) aim at understanding the relationship structure-function. With advances in biology, isolation and purification of scarce populations of cells or subcellular structures may not lead to enough biological material, for processing for LM and TEM. A protocol for preparation of scarce biological samples is presented. It is based on pre-embedding the biological samples, suspensions or pellets, in bovine serum albumin (BSA) and bis-acrylamide (BA), cross-linked and polymerized. This preparation provides a simple and reproducible technique to process biological materials, present in limited quantities that can not be amplified, for light and transmission electron microscopy.

BrdU immunohistochemistry for studying adult neurogenesis: paradigms, pitfalls, limitations, and validation.

Bromodeoxyuridine (BrdU) is a thymidine analog that incorporates DNA of dividing cells during the S-phase of the cell cycle. As such, BrdU is used for birth dating and monitoring cell proliferation. BrdU immunohistochemistry has been instrumental for the study of the development of the nervous system, and to confirm that neurogenesis occurs in the adult mammalian brain, including in human. However, the use of BrdU for studying neurogenesis is not without pitfalls and limitations. BrdU is a toxic and mutagenic substance. It triggers cell death, the formation of teratomas, alters DNA stability, lengthens the cell cycle, and has mitogenic, transcriptional and translational effects on cells that incorporate it. All of which have profound consequences on neurogenesis. BrdU is not a marker of the S-phase of the cell cycle. As a thymidine analog, it is a marker of DNA synthesis. Therefore, studying neurogenesis with BrdU requires distinguishing cell proliferation and neurogenesis from other events involving DNA synthesis, like DNA repair, abortive cell cycle reentry and gene duplication. BrdU labeling is currently the most used technique for studying adult neurogenesis in situ. However in many instances, appropriate controls have been overlooked and events reported as the generation of new neuronal cells in the adult brain misinterpreted, which makes BrdU labeling one of the most misused techniques in neuroscience.

Stem cells engineering for cell-based therapy.

Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

OTI-010 Osiris Therapeutics/JCR Pharmaceuticals.

Osiris Therapeutics is developing the donor-derived mesenchymal stem cell (MSC) therapy OTI-010, which repopulates the bone marrow stroma and thus supports engraftment of hematopoietic stem cells from the same donor. This stem cell therapy, which has been awarded Orphan Drug status, is currently in development for the potential enhancement of bone marrow transplants in cancer patients, for the prevention of graft versus host disease (GVHD), and for the treatment of Crohn's disease. Japanese licensee JCR Pharmaceuticals is investigating the therapy for the potential treatment of GVHD in patients undergoing bone marrow transplantation to treat leukemia. Phase II clinical trials in acute gastrointestinal GVHD and in adult and pediatric patients with treatment-refractory severe GVHD are currently underway.

The therapeutic potential of adult neural stem cells.

Neural stem cells (NSCs) are self-renewing, multipotent cells that generate the neuronal and glial cells of the nervous system. In mammals, contrary to long-held belief, neurogenesis occurs in the adult brain, and NSCs reside in the adult central nervous system. Thus, the brain may be amenable to repair following damage, and new avenues for cell-based therapy are being considered for the treatment of brain disease and injury, such as the stimulation of endogenous progenitor cells, the transplantation of adult-derived neural progenitor and stem cells, and, in particular, autologous cell transplantation. Although significant advances in this field have been made over the past decade, the adult NSC remains an elusive cell for study, and researchers are facing multiple challenges to the development of therapeutic applications from adult NSC research. Among these challenges are the identification and characterization of NSCs in vivo and in vitro, the understanding of the physiology of newly generated neuronal cells in the adult brain, the stimulation of endogenous progenitor cells to promote functional recovery, and the isolation and culture of homogenous populations of neural progenitor or stem cells from the adult brain for cell-based therapy.

HuCNS-SC (StemCells).

HuCNS-SC, a proprietary human neural stem cells product, is being developed as a cellular therapy for the potential treatment of Batten disease, one of a group of disorders known as neural ceroid lipofuscinoses (NCL). Developer StemCells is also investigating the therapy for spinal cord injury and other central nervous system disorders, such as demyelinating disease, stroke and Alzheimer's disease. A phase I trial of HuCNS-SC for infantile and late-infantile NCL has been initiated, following the March 2006 U.S. Food and Drug Administration approval of StemCells' investigational new drug application.

Adult neurogenesis in mammals.

With the recent confirmation that neurogenesis occurs in the adult brain, and that neural stem cells reside in the adult central nervous system (CNS), the function of newly generated neuronal cells in the adult brain is the source of intense research and debate. Neurogenesis is modulated by a wide variety of physiopathological conditions and environmental stimuli, offering the possibility that newly generated neuronal cells might be functionally associated with the response to these processes. Newly generated neuronal cells in the hippocampus have also been implicated in mechanisms of learning, memory and depression. However, a number of studies have challenged some of these findings, and the roles of newly generated neuronal cells in the functioning of the CNS remain to be fully understood. Neurogenesis has been shown to increase bilaterally in the adult brain and new neuronal cells are generated at sites of degeneration in the brain during disease and after injuries. Taken together, these findings suggest that new neuronal cells may be involved in processes such as homeostasis of brain tissue, regeneration, plasticity, and neuroadaptation.

Adult neurogenesis and neuroplasticity.

After cerebral strokes and traumatic brain injuries (TBIs), there is a striking amount of neurological recovery in the following months and years, despite often-permanent structural damage. Though the mechanisms underlying such recovery are not fully understood, properties of plasticity of the central nervous system (CNS), such as the reorganization of the pre-existing network and axonal sprouting have been implicated in the recovery. With the recent evidences that neurogenesis occurs in the adult brain, and neural stem cells (NSCs) reside in the adult CNS, the involvement of newly generated neuronal cells in the recovery following injury to the CNS remains to be established. Neurogenesis is increased bilaterally in the dentate gyrus (DG) and the subventicular zone (SVZ) after cerebral strokes and TBIs, and new neuronal cells are generated at the sites of injury, where they replace some of the degenerated nerve cells. Newly generated neuronal cells at the sites of injury may represent an attempt by the CNS to regenerate itself after injury, whereas the increased neurogenesis in the DG and SVZ would also contribute to the CNS plasticity. Thus, injury-induced neurogenesis may contribute to the recovery and plasticity of the CNS.

Stroke-induced neurogenesis: physiopathology and mechanisms.

Long-term disabilities are the main outcome of cerebral strokes, though some of the deficits show receding signs in the weeks and months following the "brain attack". Studies show that neurogenesis is induced in the hippocampus and subventricular zone (SVZ) in animal models of ischemia, and that new neurons are generated at the sites of degeneration, where they replace some of the lost nerve cells. The enhanced neurogenesis suggests the involvement of the hippocampus and SVZ in the physiopathology of cerebral strokes, and the generation of new neuronal cells at the sites of degeneration suggests that the central nervous system (CNS) may attempt to repair itself. In this manuscript, we will review the studies on adult neurogenesis in cerebral strokes, discuss the contribution of adult neurogenesis to the physiopathology of strokes, and its underlying mechanisms.