Histopathological assessment of OASIS Ultra on critical-sized wound healing: a pilot study

Bioengineering Skin Substitutes for Wound Management-Perspectives and Challenges

Non-healing wounds and skin losses constitute significant challenges for modern medicine and pharmacology. Conventional methods of wound treatment are effective in basic healthcare; however, they are insufficient in managing chronic wound and large skin defects, so novel, alternative methods of therapy are sought. Among the potentially innovative procedures, the use of skin substitutes may be a promising therapeutic method. Skin substitutes are a heterogeneous group of materials that are used to heal and close wounds and temporarily or permanently fulfill the functions of the skin. Classification can be based on the structure or type (biological and synthetic). Simple constructs (class I) have been widely researched over the years, and can be used in burns and ulcers. More complex substitutes (class II and III) are still studied, but these may be utilized in patients with deep skin defects. In addition, 3D bioprinting is a rapidly developing method used to create advanced skin constructs and their appendages. The aforementioned therapies represent an opportunity for treating patients with diabetic foot ulcers or deep skin burns. Despite these significant developments, further clinical trials are needed to allow the use skin substitutes in the personalized treatment of chronic wounds.

Recent advances in decellularized biomaterials for wound healing

The skin is one of the most essential organs in the human body, interacting with the external environment and shielding the body from diseases and excessive water loss. Thus, the loss of the integrity of large portions of the skin due to injury and illness may lead to significant disabilities and even death. Decellularized biomaterials derived from the extracellular matrix of tissues and organs are natural biomaterials with large quantities of bioactive macromolecules and peptides, which possess excellent physical structures and sophisticated biomolecules, and thus, promote wound healing and skin regeneration. Here, we highlighted the applications of decellularized materials in wound repair. First, the wound-healing process was reviewed. Second, we elucidated the mechanisms of several extracellular matrix constitutes in facilitating wound healing. Third, the major categories of decellularized materials in the treatment of cutaneous wounds in numerous preclinical models and over decades of clinical practice were elaborated. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues for research on decellularized biomaterials-based wound treatment.

Comparing the application of various engineered xenografts for skin defects: A systematic review

INTRODUCTION

Xenografts are a now a cornerstone in the management of wound dressings. Promising results were achieved since 1960 in the application of skin substitute for skin defects.

OBJECTIVE

The objective of this study was to evaluate the efficacy of various xenografts.

METHODS

A literature research was conducted using the following query: 'Porcine skin dermatology substitute', 'bovine skin dermatology substitute', 'xenograft skin substitute dermatology', 'xenografts skin defect', 'porcine skin defect', 'bovine skin defect'.

RESULTS

The review yielded 35 articles pertaining to the topic. Main indications for porcine and bovine xenograft application were burn wounds and post-traumatic wounds, respectively. Mean discharge date or length of stay was at the 6th day after porcine application, and the time of graft healing was reported for 33.7% (n = 510) of patients. Promising results were seen with Matriderm and split-thickness skin graft. Most wounds achieved an excellent cosmetic result with full range of motion and a smooth contour appearance. A great variety of tissue substitutes exist, and the choice of graft application should depend on a patient's factors, product availability, wound type, size, and physician's factors.

CONCLUSION

In summary, xenografts are more economic and affordable but have higher risk of infections compared to allografts.

Hyperbaric and topical oxygen therapies in thermal burn wound healing: a review

OBJECTIVE

This review aims to evaluate the effectiveness of the two most commonly used oxygen delivery methods for the treatment of thermal burn wound healing: hyperbaric oxygen therapy (HBOT) and topical oxygen therapy (TOT).

METHOD

The PubMed database was searched for articles discussing the use of HBOT or TOT in the treatment of thermal burns.

RESULTS

The search yielded 43,406 articles, of which 28 (23 HBOT, 5 TOT) met the inclusion criteria. Both experimental and clinical studies have demonstrated conflicting results after treating thermal burns with HBOT or TOT. Overall, 14/23 studies demonstrated positive results for HBOT on the healing of burn wounds and associated complications, such as oedema and pain. Findings from these studies showed it can reduce morbidity and mortality in certain high-risk groups such as those with diabetes or extensive burns. Although the five studies (one human and four animal trials) reviewing TOT showed promising outcomes, this therapeutic modality has not been well investigated.

CONCLUSION

Therapeutic use of HBOT in thermal burns has been popular in the past but its use remains controversial due to inconsistent results, serious side-effects, lack of convenience and high costs. The use of TOT in the management of burns needs further exploration by scientists and clinicians alike, in addition to the implementation of a standardised treatment protocol.

Clinical benefits of small intestinal submucosa extracellular matrix and review of the evidence

There is a clear scientific rationale for using cellular, acellular and matrix-like products (CAMPs), such as small intestinal submucosa extracellular matrix (SIS-ECM), in hard-to-heal wounds, such as diabetic foot ulcers (DFUs), venous leg ulcers (VLUs), pressure ulcers and arterial leg ulcers. The clinical evidence supporting the use of SIS-ECM has grown over the past several decades. This evidence base now encompasses a wide range of hard-to-heal wound indications, including DFUs and VLUs, as well as increasingly complex acute wound indications, such as delayed postoperative wounds, traumatic wounds and burns. The aim of this article is to review the steadily amassed body of evidence that describes the clinical outcomes associated with treatment with SIS-ECM and its potential implications for the overall costs of treatment.

Skin substitutes for the management of mohs micrographic surgery wounds: a systematic review

The data on skin substitute usage for managing Mohs micrographic surgery (MMS) wounds remain limited. This systematic review aimed to provide an overview of skin substitutes employed for MMS reconstruction, summarize clinical characteristics of patients undergoing skin substitute-based repair after MMS, and identify advantages and limitations of skin substitute implementation. A systematic review of Ovid MEDLINE, EMBASE, Cochrane Library, and Web of Science databases, from inception to April 7, 2021, identified all cases of MMS defects repaired using skin substitutes. A total of 687 patients were included. The mean patient age was 70 years (range: 6-98 years). Commonly used skin substitutes were porcine collagen (n = 397), bovine collagen (n = 78), Integra (n = 53), Hyalofill (n = 43), amnion/chorion-derived grafts (n = 40), and allogeneic epidermal-dermal composite grafts (n = 35). Common factors influencing skin substitute selection were cost, healing efficacy, cosmetic outcome, patient comfort, and ease of use. Some articles did not specify patient and wound characteristics. Skin substitute usage in MMS reconstruction is not well-guided. Blinded randomized control trials comparing the efficacy of skin substitutes and traditional repair methods are imperative for establishing evidence-based guidelines on skin substitute usage following MMS.

Application expansion of small intestinal submucosa extracellular matrix in complex and surgical wounds

A wound is hard-to-heal or complex when the defect fails to progress through the normal stages of wound healing in a timely fashion. Hard-to-heal wounds such as diabetic foot or venous leg ulcers can be long-lasting conditions. Alternatively, complex acute wounds that occur from trauma, burns, postoperative, necrosis and some dermatological diseases can also result in hard-to-heal wounds. This article reviews important considerations in the management of complex acute wounds, such as time to wound closure, pain, scarring, patient satisfaction and identification of options that can promote healing of grafts and flaps, while reducing donor-site morbidity. Primary research has demonstrated the inherent benefits of small intestinal submucosa extracellular matrix (SIS-ECM), a naturally occurring porcine matrix that promotes development of dermis-like tissue in both complex acute and hard-to-heal wounds. Presently, the literature provides mostly case studies demonstrating the benefits of SIS-ECM in the management of complex acute wounds. The available case series suggest emerging clinical benefits including rapid time to coverage, avoidance of donor-site complications and development of granulation tissue in locations of low circulation, which improves poor graft sites, potentially reducing dehiscence and providing support for reconstruction flaps and grafts.

Clinical benefits of small intestinal submucosa extracellular matrix and review of the evidence

There is a clear scientific rationale for using cellular, acellular and matrix-like products (CAMPs), such as small intestinal submucosa extracellular matrix (SIS-ECM), in hard-to-heal wounds, such as diabetic foot ulcers (DFUs), venous leg ulcers (VLUs), pressure ulcers and arterial leg ulcers. The clinical evidence supporting the use of SIS-ECM has grown over the past several decades. This evidence base now encompasses a wide range of hard-to-heal wound indications, including DFUs and VLUs, as well as increasingly complex acute wound indications, such as delayed postoperative wounds, traumatic wounds and burns. The aim of this article is to review the steadily amassed body of evidence that describes the clinical outcomes associated with treatment with SIS-ECM and its potential implications for the overall costs of treatment.

Comparative evaluation of the efficacy of ozone therapy and low level laser therapy on oral mucosal wound healing in rat experimental model

OBJECTIVE

The aim of the present study was to evaluate and compare the effectiveness of ozone therapy and low-level laser therapy (LLLT) on healing of oral mucosal wounds in rats through histological assessment.

METHODS

Thirty male Wistar rats were employed in this study. Following a 5-mm surgical wound created on the buccal mucosa, the rats were randomly distributed into 3 groups of 10: (1) ozone group (treated with topical gaseous ozone), (2) laser group (treated with LLLT), and (3) control group (received no treatment). Following the sacrifice of rats on day 21, samples were taken from rats' buccal mucosa for histological assay and scoring. The data were analyzed using Mann-Whitney test.

RESULTS

Ozone and laser groups demonstrated reduced acute inflammation scores compared to control group (p=.01), while no significant differences were observed between the ozone and laser groups (p = 1.00). Similarly, ozone and laser groups showed higher histological tissue repair scores than the control group (p=.00), and no difference was found between ozone and laser groups (p=.76). On the other hand, no significant difference in expression of TNF-α (p=.33) and TGF-β1 (p=.13) was identified between ozone, laser and control samples.

CONCLUSION

The present study demonstrated that both adjunctive ozone therapy and LLLT with a 940 nm diode laser provided significant improvement in parameters of acute inflammation and tissue repair in surgical oral mucosal wounds in rats.

Porcine Small Intestinal Submucosa Alters the Biochemical Properties of Wound Healing: A Narrative Review

Among the many biological scaffold materials currently available for clinical use, the small intestinal submucosa (SIS) is an effective material for wound healing. SIS contains numerous active forms of extracellular matrix that support angiogenesis, cell migration, and proliferation, providing growth factors involved in signaling for tissue formation and assisting wound healing. SIS not only serves as a bioscaffold for cell migration and differentiation, but also restores the impaired dynamic reciprocity between cells and the extracellular matrix, ultimately driving wound healing. Here, we review the evidence on how SIS can shift the biochemical balance in a wound from chronic to an acute state.

The Role of the Extracellular Matrix (ECM) in Wound Healing: A Review

The extracellular matrix (ECM) is a 3-dimensional structure and an essential component in all human tissues. It is comprised of varying proteins, including collagens, elastin, and smaller quantities of structural proteins. Studies have demonstrated the ECM aids in cellular adherence, tissue anchoring, cellular signaling, and recruitment of cells. During times of integumentary injury or damage, either acute or chronic, the ECM is damaged. Through a series of overlapping events called the wound healing phases—hemostasis, inflammation, proliferation, and remodeling—the ECM is synthesized and ideally returned to its native state. This article synthesizes current and historical literature to demonstrate the involvement of the ECM in the varying phases of the wound healing cascade.

Decellularized Tissues for Wound Healing: Towards Closing the Gap Between Scaffold Design and Effective Extracellular Matrix Remodeling

The absence or damage of a tissue is the main cause of most acute or chronic diseases and are one of the appealing challenges that novel therapeutic alternatives have, in order to recover lost functions through tissue regeneration. Chronic cutaneous lesions are the most frequent cause of wounds, being a massive area of regenerative medicine and tissue engineering to have efforts to develop new bioactive medical products that not only allow an appropriate and rapid healing, but also avoid severe complications such as bacterial infections. In tissue repair and regeneration processes, there are several overlapping stages that involve the synergy of cells, the extracellular matrix (ECM) and biomolecules, which coordinate processes of ECM remodeling as well as cell proliferation and differentiation. Although these three components play a crucial role in the wound healing process, the ECM has the function of acting as a biological platform to permit the correct interaction between them. In particular, ECM is a mixture of crosslinked proteins that contain bioactive domains that cells recognize in order to promote migration, proliferation and differentiation. Currently, tissue engineering has employed several synthetic polymers to design bioactive scaffolds to mimic the native ECM, by combining biopolymers with growth factors including collagen and fibrinogen. Among these, decellularized tissues have been proposed as an alternative for reconstructing cutaneous lesions since they maintain the complex protein conformation, providing the required functional domains for cell differentiation. In this review, we present an in-depth discussion of different natural matrixes recently employed for designing novel therapeutic alternatives for treating cutaneous injuries, and overview some future perspectives in this area.

Macroscopic, Histologic, and Immunomodulatory Response of Limb Wounds Following Intravenous Allogeneic Cord Blood-Derived Multipotent Mesenchymal Stromal Cell Therapy in Horses

Limb wounds are common in horses and often develop complications. Intravenous multipotent mesenchymal stromal cell (MSC) therapy is promising but has risks associated with intravenous administration and unknown potential to improve cutaneous wound healing. The objectives were to determine the clinical safety of administering large numbers of allogeneic cord blood-derived MSCs intravenously, and if therapy causes clinically adverse reactions, accelerates wound closure, improves histologic healing, and alters mRNA expression of common wound cytokines. Wounds were created on the metacarpus of 12 horses. Treatment horses were administered 1.51-2.46 × 10⁸ cells suspended in 50% HypoThermosol FRS, and control horses were administered 50% HypoThermosol FRS alone. Epithelialization, contraction, and wound closure rates were determined using planimetric analysis. Wounds were biopsied and evaluated for histologic healing characteristics and cytokine mRNA expression. Days until wound closure was also determined. The results indicate that 3/6 of treatment horses and 1/6 of control horses experienced minor transient reactions. Treatment did not accelerate wound closure or improve histologic healing. Treatment decreased wound size and decreased all measured cytokines except transforming growth factor-β3. MSC intravenous therapy has the potential to decrease limb wound size; however, further work is needed to understand the clinical relevance of adverse reactions.

Impact of Deserosalization on Small Bowel Anastomosis Healing in Swine: A Pilot Study

BACKGROUND

Healing is related to gastrointestinal anastomotic leak, which is a severe and common complication. This study aimed to investigate the feasibility and the impact of deserosalization on healing of jejuno-jejunal anastomoses in an animal model.

MATERIALS AND METHODS

Seven swine underwent three types of side-to-side jejuno-jejunal anastomosis twice and survived seven days. Three different types of jejuno-jejunal side-to-side anastomoses were performed twice at 20-cm distance from each other in each animal: no serosa removal, one-sided, and two-sided serosa removal, respectively. Bursting pressure, tissue hydroxyproline concentration, and pathology scores were evaluated.

RESULTS

Hydroxyproline tissue concentration was a mean±standard deviation of 0.37±0.09, 0.38±0.08, and 0.30±0.05 nmoI/ml respectively (p<0.05). Bursting pressure was a mean±standard deviation of 59.02±8.60, 73.20±11.09, and 100.01±7.49 mmHg, respectively (p<0.001). The histopathological assessment did not find any statistically significant differences.

CONCLUSION

Deserosalization in jejuno-jejunal anastomosis was technically feasible and seemed to improve mechanical strength and collagen deposition in this experimental porcine model. Further investigation is warranted.

Decellularized xenografts in regenerative medicine: From processing to clinical application

Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.

Skin substitutes for acute and chronic wound healing: an updated review

Background: Skin substitutes are designed to accelerate wound healing by providing replacement of extracellular matrix and can be used to promote healing of both acute and chronic wounds.Aim: To describe advantages, disadvantages, and indications for different skin substitutes with the intention of providing a systematic framework that clinicians can easily utilize in clinical practice.Materials and method: We conducted a PubMed, Cochrane Library, and company website search for publications using various search terms associated with skin substitutes.Results: Skin substitutes can be categorized as epidermal, dermal, and composite, depending on the skin component they contain, and further split into different categories depending on their composition and source of material, including xenograft, acellular allograft, cellular allograft, autograft, and synthetic skin substitutes. Because there is no ideal option for skin substitutes that meet all the criteria for optimal wound healing, there is ongoing research evaluating and developing different skin substitute options.Conclusion: Our model of skin substitutes was organized based on the different layers of cutaneous involvement and the origin of the product material. We believe that this framework provides a practical guide for selection of the most appropriate skin substitute based on clinical indication.

The bolster technique utilising small intestinal submucosa wound matrix: A novel approach to wound treatment

Managing acute wounds with soft tissue loss can be very challenging for both patients and physicians. Successful wound healing depends on several factors including exudate control, prevention of infection, and moisture balance. In this case series, we describe a novel combination treatment method utilising small intestinal submucosa wound matrix (SISWM) with the bolster technique as a way of assisting the integration of collagen‐based wound treatment products into the base of complex wounds with the intent of restoring a dysfunctional extracellular matrix. In case 1, a 44‐year‐old female presented with an acute wound resulting from a spider bite to the posterior aspect of the right knee. In case 2, a 12‐year‐old male sustained multiple injuries to his right foot from an all‐terrain vehicle accident. In case 3, an 80‐year‐old female on anticoagulants sustained an avulsion injury to her left lower leg. In case 4, a 41‐year‐old female sustained a severe complex avulsion injury to the dorsal left forearm sustained from a dog bite. All patients were successfully treated with SISWM and the bolster technique, and their wounds healed completely within 6 weeks. The bolster technique, when combined with an SISWM, is a novel method designed to enable the SISWM to impart its wound healing properties to these complex traumatic wounds. This case series presents treating clinicians with a different treatment methodology to assist the patient in achieving a successful outcome.

miR‑339‑5p negatively regulates loureirin A‑induced hair follicle stem cell differentiation by targeting DLX5

Our previous study indicated that loureirin A induces hair follicle stem cell (HFSC) differentiation through Wnt/β-catenin signaling pathway activation. However, if and how microRNAs (miRNAs/miRs) modulate loureirin A-induced differentiation remains to be elucidated. In the present study, HFSCs were separated from the vibrissae of rats and identified by CD34 and keratin, type 1 cytoskeletal (K)15 expression. Microarray-based miRNA profiling analysis revealed that miR-339-5p was downregulated in loureirin A-induced HFSC differentiation. miR-339-5p overexpression by transfection with miR-339-5p mimics markedly inhibited the expression of K10 and involucrin, which are markers of epidermal differentiation, whereas inhibition of miR-339-5p by miR-339-5p inhibitor transfection promoted the expression of K10 and involucrin. These results suggest that miR-339-5p is a negative regulator of HFSC differentiation following induction by loureirin A. These findings were confirmed by a luciferase assay. Homeobox protein DLX-5 (DLX5) was identified as a direct target of miR-339-5p. Furthermore, it was demonstrated that miR-339-5p inhibited DLX5. Overexpression of miR-339-5p by mimic transfection significantly inhibited protein Wnt-3a (Wnt3a) expression, while inhibition of miR-339-5p by inhibitor transfection significantly increased the expression of Wnt3a. Furthermore, small interfering RNA targeting DLX5 was transfected into HFSCs, and western blot analysis revealed that Wnt3a, involucrin and K10 expression was significantly downregulated. Taken together, these results suggest that miR-339-5p negatively regulated loureirin A-induced HFSC differentiation by targeting DLX5, resulting in Wnt/β-catenin signaling pathway inhibition. This may provide a possible therapeutic target for skin repair and regeneration.