Fibrin Glue Enhances Adipose-Derived Stromal Cell Cytokine Secretion and Survival Conferring Accelerated Diabetic Wound Healing

Evaluation of bone marrow-derived mesenchymal stem cells with eggshell membrane for full-thickness wound healing in a rabbit model

Biomaterials capable of managing wounds should have essential features like providing a natural microenvironment for wound healing and as support material for stimulating tissue growth. Eggshell membrane (ESM) is a highly produced global waste due to increased egg consumption. The unique and fascinating properties of ESM allow their potential application in tissue regeneration. The wound healing capacity of bone marrow-derived mesenchymal stem cells (BM-MSCs), ESM, and their combination in rabbits with full-thickness skin defect (2 × 2 cm2) was evaluated. Twenty-five clinically healthy New Zealand White rabbits were divided into five groups of five animals each, with group A receiving no treatment (control group), group B receiving only fibrin glue (FG), group C receiving FG and ESM as a dressing, group D receiving FG and BM-MSCs, and group E receiving a combination of FG, ESM, and BM-MSCs. Wound healing was assessed using clinical, macroscopical, photographic, histological, histochemical, hematological, and biochemical analysis. Macroscopic examination of wounds revealed that healing was exceptional in group E, followed by groups D and C, compared to the control group. Histopathological findings revealed improved quality and a faster rate of healing in group E compared to groups A and B. In addition, healing in group B treated with topical FG alone was nearly identical to that in control group A. However, groups C and D showed improved and faster recovery than control groups A and B. The macroscopic, photographic, histological, and histochemical evaluations revealed that the combined use of BM-MSCs, ESM, and FG had superior and faster healing than the other groups.

Platelet-rich plasma combined with lyophilizing thrombin powder for the treatment of complicated enterocutaneous fistula: a case report

Background

Enterocutaneous fistula is one of the most challenging problems facing surgeons. In severe cases, a large amount of fluid loss can lead to problems such as water and electrolyte acid-base imbalance, malnutrition, infection, and organ dysfunction. Here we reported a case of platelet-rich plasma combined with lyophilizing thrombin powder for the treatment of complicated enterocutaneous fistula.

Case presentation

A 48-year-old male, more than 2 years after the operation of abdominal trauma, the leakage of the fistula in the right upper abdominal wall was accompanied by fever for 3 days. The Contrast Fistulography and upper abdomen CT accurately depicted the entry of the meglumine diatrizoate into the small intestine through the small fistula. The patient had a large abdominal wall defect and severe intestinal adhesions. Reoperation may lead to more serious ECF. Therefore, we decided to seal the fistulas with PRP combined with lyophilizing thrombin powder.

Conclusions

The findings in this case report suggest that the combination of PRP and lyophilized thrombin powder holds promise as a viable approach for managing ECF in patients with chronic abdominal wall fistulas, as it appears to facilitate fistula closure, reduce healing time, and improve patient outcomes.

Mesenchymal Stem Cell Extracellular Vesicles from Tissue-Mimetic System Enhance Epidermal Regeneration via Formation of Migratory Cell Sheets

BACKGROUND

The secretome of adipose-derived mesenchymal stem cells (ASCs) offers a unique approach to understanding and treating wounds, including the critical process of epidermal regeneration orchestrated by keratinocytes. However, 2D culture techniques drastically alter the secretory dynamics of ASCs, which has led to ambiguity in understanding which secreted compounds (e.g., growth factors, exosomes, reactive oxygen species) may be driving epithelialization.

METHODS

A novel tissue-mimetic 3D hydrogel system was utilized to enhance the retainment of a more regenerative ASC phenotype and highlight the functional secretome differences between 2D and 3D. Subsequently, the ASC-secretome was stratified by molecular weight and the presence/absence of extracellular vesicles (EVs). The ASC-secretome fractions were then evaluated to assess for the capacity to augment specific keratinocyte activities.

RESULTS

Culture of ASCs within the tissue-mimetic system enhanced protein secretion ~ 50%, exclusively coming from the > 100 kDa fraction. The ASC-secretome ability to modulate epithelialization functions, including migration, proliferation, differentiation, and morphology, resided within the "> 100 kDa" fraction, with the 3D ASC-secretome providing the greatest improvement. 3D ASC EV secretion was enhanced two-fold and exhibited dose-dependent effects on epidermal regeneration. Notably, ASC-EVs induced morphological changes in keratinocytes reminiscent of native regeneration, including formation of stratified cell sheets. However, only 3D-EVs promoted collective cell sheet migration and an epithelial-to-mesenchymal-like transition in keratinocytes, whereas 2D-EVs contained an anti-migratory stimulus.

CONCLUSION

This study demonstrates how critical the culture environment is on influencing ASC-secretome regenerative capabilities. Additionally, the critical role of EVs in modulating epidermal regeneration is revealed and their translatability for future clinical therapies is discussed.

Tailoring the secretome composition of mesenchymal stem cells to augment specific functions of epidermal regeneration: an in vitro diabetic model

Introduction

Wound healing consists of a dynamic series of events that are highly dependent on paracrine factors for proper progression through the phases of wound healing. Inappropriate progression through the phases is associated with insufficient epidermal regeneration (i.e., re-epithelialization) of wounds and subsequent propagation of chronic wounds, such as diabetic ulcers, which are associated with increased patient morbidity. Recently, investigation into the dynamic secretome of Adipose-derived Mesenchymal Stem Cells (ASCs), have shown promise in augmenting the wound healing response of chronic diabetic wounds. However, currently utilized 2D culture techniques are known to drastically alter the regenerative phenotype of ASCs. In this study a novel tissue-mimetic 3D system was utilized as a means to culture ASCs.

Methods

The capacity for the ASC secretome to augment epidermal regeneration activity was then evaluated after exposure of ASCs to "wound priming stimuli" in 2D and 3D. The priming stimuli consisted of coating the 2D and 3D systems with the wound matrix proteins, collagen type I, fibronectin, and fibrin. To understand the potential benefit of the ASC secretome in the context of diabetic wounds, keratinocytes (KCs) were exposed to super-physiological glucose levels to induce a diabetic-like phenotype (idKCs).

Results

Relative to KCs, idKC exhibited a 52% and 23% decline in proliferation and migration, respectively. Subsequently, analyses of the ASC secretome were performed. ASC conditioned media (ASC-CM) from tissue-mimetic culture demonstrated a > 50% increase secretion of proteins and a 2-fold increase in secreted EVs, relative to 2D culture. Interestingly, the different priming stimuli did not alter the total amount of protein or EVs secreted within the tissue-mimetic system. However, evaluation of specific soluble proteins via ELISA revealed significant differences in key epidermal regeneration factors, such as EGF, IGF-1, FGF-2, MMP-1, TIMP-1, and TGFβ-1. Additionally, the relative effect of ASC-EVs from the 2D and 3D system on idKCs epidermal regeneration functionality varied significantly, with EVs from 3D-Collagen culture providing the most significant benefit on idKC activity.

Discussion

Together, these data support the utilization of tissue-mimetic culture system to enhance the adaptability and secretory activity of MSC-like populations in order to generate tailored biologics, via priming stimuli, for specific wound healing applications.

The use of commercial fibrin glue in dermal replacement material reduces angiogenic and lymphangiogenic gene and protein expression in vitro

BACKGROUND

Commercial fibrin glue is increasingly finding its way into clinical practice in surgeries to seal anastomosis, and initiate hemostasis or tissue repair. Human biological glue is also being discussed as a possible cell carrier. To date, there are only a few studies addressing the effects of fibrin glue on the cell-molecular level. This study examines the effects of fibrin glue on angiogenesis and lymphangiogenesis, as well as adipose-derived stem cells (ASCs) with a focus on gene and protein expression in scaffolds regularly used for tissue engineering approaches.

METHODS

Collagen-based dermal regeneration matrices (DRM) were seeded with human umbilical vein endothelial cells (HUVEC), human dermal lymphatic endothelial cells (LECs), or adipose-derived stem cells (ASC) and fixed with or without fibrin glue according to the experimental group. Cultures were maintained for 1 and 7 days. Finally, angiogenic and lymphangiogenic gene and protein expression were measured with special regard to subtypes of vascular endothelial growth factor (VEGF) and corresponding receptors using Multiplex-qPCR and ELISA assays. In addition, the hypoxia-induced factor 1-alpha (HIF1a) mediated intracellular signaling pathways were included in assessments to analyze a hypoxic encapsulating effect of fibrin polymers.

RESULTS

All cell types reacted to fibrin glue application with an alteration of gene and protein expression. In particular, vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor B (VEGFB), vascular endothelial growth factor C (VEGFC), vascular endothelial growth receptor 1 (VEGFR1/FLT1), vascular endothelial growth receptor 2 (VEGFR2/KDR), vascular endothelial growth receptor 3 (VEGFR3/FLT4) and Prospero Homeobox 1 (PROX1) were depressed significantly depending on fibrin glue. Especially short-term fibrin effect led to a continuous downregulation of respective gene and protein expression in HUVECs, LECs, and ASCs.

CONCLUSION

Our findings demonstrate the impact of fibrin glue application in dermal regeneration with special regard to angiogenesis and lymphangiogenesis. In particular, a short fibrin treatment of 24 hours led to a decrease in gene and protein levels of LECS, HUVECs, and ASCs. In contrast, the long-term application showed less effect on gene and protein expressions. Therefore, this work demonstrated the negative effects of fibrin-treated cells in tissue engineering approaches and could affect wound healing during dermal regeneration.

Tissue Engineering-Based Strategies for Diabetic Foot Ulcer Management

Significance: Diabetic foot ulcers (DFU) are a mounting problem with the increasingly frail population. Injuries that would otherwise heal are kept open by risk factors such as diabetes, obesity, and age-related conditions, which interferes with the natural wound healing processes. Recent Advances: This review summarizes recent advancements in the field of tissue engineering for the treatment of DFUs. FDA-approved approaches, including signaling-based therapies, stem cell therapies, and skin substitutes are summarized and cutting-edge experimental technologies that have the potential to manage chronic wounds, such as skin printing, skin organogenesis, skin self-assembly, and prevascularization, are discussed. Critical Issues: The standard of care for chronic wounds involves wound debridement, wound dressings, and resolving the underlying cause such as lowering the glycemic index and reducing wound pressure. Current DFU treatments are limited by low wound closure rates and poor regrown skin quality. New adjuvant therapies that facilitate wound closure in place of or in conjunction with standard care are critically needed. Future Directions: Tissue engineering strategies are limited by the plasticity of adult human cells. In addition to traditional techniques, genetic modification, although currently an emerging technology, has the potential to unlock human regeneration and can be incorporated in future therapeutics.

Adipose-Derived Stromal Cells for Chronic Wounds: Scientific Evidence and Roadmap Toward Clinical Practice

Chronic wounds, ie, non-healing ulcers, have a prevalence of ~1% in the general population. Chronic wounds strongly affect the quality of life and generate considerable medical costs. A fraction of chronic wounds will heal within months of appropriate treatment; however, a significant fraction of patients will develop therapy-refractory chronic wounds, leading to chronic pain, infection, and amputation. Given the paucity of therapeutic options for refractory wounds, cell therapy and in particular the use of adipose-derived stromal cells (ASC) has emerged as a promising concept. ASC can be used as autologous or allogeneic cells. They can be delivered in suspension or in 3D cultures within scaffolds. ASC can be used without further processing (stromal vascular fraction of the adipose tissue) or can be expanded in vitro. ASC-derived non-cellular components, such as conditioned media or exosomes, have also been investigated. Many in vitro and preclinical studies in animals have demonstrated the ASC efficacy on wounds. ASC efficiency appears to occurs mainly through their regenerative secretome. Hitherto, the majority of clinical trials focused mainly on safety issues. However more recently, a small number of randomized, well-controlled trials provided first convincing evidences for a clinical efficacy of ASC-based chronic wound therapies in humans. This brief review summarizes the current knowledge on the mechanism of action, delivery and efficacy of ASC in chronic wound therapy. It also discusses the scientific and pharmaceutical challenges to be solved before ASC-based wound therapy enters clinical reality.

Differences of embedding adipose-derived stromal cells in natural and synthetic scaffolds for dermal and subcutaneous delivery

Background

In recent years, adipose-derived stromal cells (ASCs) have been heavily studied for soft tissue regeneration, augmentation, and dermal wound healing.

Methods

In this review, we investigated the trends in injectable scaffolds for ASC delivery in the dermis, and injectable or implantable scaffolds for ASC delivery in the subcutis. A total of 547 articles were screened across three databases; of these, 22 studies were found to be eligible and were included. The scaffolds were subdivided and analyzed based on their tissue placement (dermis or subcutis), delivery method (injected or implanted), and by the origin of the materials (natural, synthetic, and combinatory).

Results

ASCs embedded in scaffolds generally showed improved viability. Neovascularization in the transplanted tissue was greater when undifferentiated ASCs were embedded in a combinatory scaffold or if differentiated ASCs were embedded in a natural scaffold. ASCs embedded in natural materials underwent more adipogenic differentiation than ASCs embedded in synthetic scaffolds, indicating an etiologically unknown difference that has yet to be described. Increased mechanical strength of the scaffold material correlated with improved outcome measurements in the investigated studies. Wound healing studies reported reduced healing time in all except one article due to contraction of the control wounds.

Conclusions

In future clinical trials, we recommend embedding ASCs in injectable and implantable scaffolds for enhanced protection, retained viability, and improved therapeutic effects.

Trial registration

This review was registered with PROSPERO: ID=CRD42020171534.

Graphical abstract

The use of scaffolds as a vehicle for ASC delivery generally improved cell viability, angiogenesis, and wound healing in vivo compared to utilizing ASCs alone. ASCs embedded in natural materials induced more adipogenesis than ASCs embedded in synthetic materials. Adipogenic-induced ASCs further increased this effect. The included studies indicate that the seeded scaffold material influences the differentiation of ASCs in vivo. All studies investigating the mechanical strength of ASC scaffolds reported improved outcome measurements with improved mechanical strength. The results suggest that scaffolds, in general, are favorable for ASC delivery. We recommend initiating clinical studies using scaffolds based on mechanical properties and tunability to improve ASC viability. For fat regeneration, natural scaffolds are recommended.

Repair of Osteochondral Defects in Rabbit Knee Using Menstrual Blood Stem Cells Encapsulated in Fibrin Glue: A Good Stem Cell Candidate for the Treatment of Osteochondral Defects

Background

In recent years, researchers discovered that menstrual blood-derived stem cells (MenSCs) have the potential to differentiate into a wide range of tissues including the chondrogenic lineage. In this study, we aimed to investigate the effect of MenSCs encapsulated in fibrin glue (FG) on healing of osteochondral defect in rabbit model.

Methods

We examined the effectiveness of MenSCs encapsulated in FG in comparison with FG alone in the repair of osteochondral defect (OCD) lesions of rabbit knees after 12 and 24 weeks.

Results

Macroscopical evaluation revealed that the effectiveness of MenSCs incorporation with FG is much higher than FG alone in repair of OCD defects. Indeed, histopathological evaluation of FG + MenSCs group at 12 weeks post-transplantation demonstrated that defects were filled with hyaline cartilage-like tissue with proper integration, high content of glycosaminoglycan and the existence of collagen fibers especially collagen type II, as well as by passing time (24 weeks post-transplantation), the most regenerated tissue in FG + MenSCs group was similar to hyaline cartilage with relatively good infill and integration. As the same with the result of 12 weeks post-implantation, the total point of microscopical examination in FG + MenSCs group was higher than other experimental groups, however, no significant difference was detected between groups at 24 weeks (p > 0.05).

Conclusion

In summary, MenSCs as unique stem cell population, is suitable for in vivo repair of OCD defects and promising for the future clinical application.