Human-derived extracellular matrix from Wharton's jelly: An untapped substrate to build up a standardized and homogeneous coating for vascular engineering

A novel 3D biofabrication strategy to improve cell proliferation and differentiation of human Wharton's jelly mesenchymal stromal cells for cell therapy and tissue engineering

Purpose: Obtaining sufficient numbers of cells in a short time is a major goal of cell culturing in cell therapy and tissue engineering. However, current bidimensional (2D) culture methods are associated to several limitations, including low efficiency and the loss of key cell differentiation markers on cultured cells. Methods: In the present work, we have designed a novel biofabrication method based on a three-dimensional (3D) culture system (FIBRIAGAR-3D). Human Wharton's jelly mesenchymal stromal cells (HWJSC) were cultured in 3D using 100%, 75%, 50%, and 25% concentrations of fibrin-agarose biomaterials (FA100, FA75, FA50 and FA25 group) and compared with control cells cultured using classical 2D systems (CTR-2D). Results: Our results showed a significant increase in the number of cells generated after 7 days of culture, with cells displaying numerous expansions towards the biomaterial, and a significant overexpression of the cell proliferation marker KI67 was found for the FA75 and FA100 groups. TUNEL and qRT-PCR analyses demonstrated that the use of FIBRIAGAR-3D was not associated with an induction of apoptosis by cultured cells. Instead, the 3D system retained the expression of typical phenotypic markers of HWJSC, including CD73, CD90, CD105, NANOG and OCT4, and biosynthesis markers such as types-I and IV collagens, with significant increase of some of these markers, especially in the FA100 group. Finally, our analysis of 8 cell signaling molecules revealed a significant decrease of GM-CSF, IFN-g, IL2, IL4, IL6, IL8, and TNFα, suggesting that the 3D culture system did not induce the expression of pro-inflammatory molecules. Conclusion: These results confirm the usefulness of FIBRIAGAR-3D culture systems to increase cell proliferation without altering cell phenotype of immunogenicity and opens the door to the possibility of using this novel biofabrication method in cell therapy and tissue engineering of the human cornea, oral mucosa, skin, urethra, among other structures.

Development of stromal differentiation patterns in heterotypical models of artificial corneas generated by tissue engineering

Purpose: We carried out a histological characterization analysis of the stromal layer of human heterotypic cornea substitutes generated with extra-corneal cells to determine their putative usefulness in tissue engineering. Methods: Human bioartificial corneas were generated using nanostructured fibrin-agarose biomaterials with corneal stromal cells immersed within. To generate heterotypical corneas, umbilical cord Wharton's jelly stem cells (HWJSC) were cultured on the surface of the stromal substitutes to obtain an epithelial-like layer. These bioartificial corneas were compared with control native human corneas and with orthotypical corneas generated with human corneal epithelial cells on top of the stromal substitute. Both the corneal stroma and the basement membrane were analyzed using histological, histochemical and immunohistochemical methods in samples kept in culture and grafted in vivo for 12 months in the rabbit cornea. Results: Our results showed that the stroma of the bioartificial corneas kept ex vivo showed very low levels of fibrillar and non-fibrillar components of the tissue extracellular matrix. However, in vivo implantation resulted in a significant increase of the contents of collagen, proteoglycans, decorin, keratocan and lumican in the corneal stroma, showing higher levels of maturation and spatial organization of these components. Heterotypical corneas grafted in vivo for 12 months showed significantly higher contents of collagen fibers, proteoglycans and keratocan. When the basement membrane was analyzed, we found that all corneas grafted in vivo showed intense PAS signal and higher contents of nidogen-1, although the levels found in human native corneas was not reached, and a rudimentary basement membrane was observed using transmission electron microscopy. At the epithelial level, HWJSC used to generate an epithelial-like layer in ex vivo corneas were mostly negative for p63, whereas orthotypical corneas and heterotypical corneas grafted in vivo were positive. Conclusion: These results support the possibility of generating bioengineered artificial corneas using non-corneal HWJSC. Although heterotypical corneas were not completely biomimetic to the native human corneas, especially ex vivo, in vivo grafted corneas demonstrated to be highly biocompatible, and the animal cornea became properly differentiated at the stroma and basement membrane compartments. These findings open the door to the future clinical use of these bioartificial corneas.

Extracellular Matrix Coatings on Cardiovascular Materials—A Review

Vascular transplantation is an effective and common treatment for cardiovascular disease (CVD). However, the low biocompatibility of implants is a major problem that hinders its clinical application. Surface modification of implants with extracellular matrix (ECM) coatings is an effective approach to improve the biocompatibility of cardiovascular materials. The complete ECM seems to have better biocompatibility, which may give cardiovascular biomaterials a more functional surface. The use of one or several ECM proteins to construct a surface allows customization of coating composition and structure, possibly resulting in some unique functions. ECM is a complex three-dimensional structure composed of a variety of functional biological macromolecules, and changes in the composition will directly affect the function of the coating. Therefore, understanding the chemical composition of the ECM and its interaction with cells is beneficial to provide new approaches for coating surface modification. This article reviews novel ECM coatings, including coatings composed of intact ECM and biomimetic coatings tailored from several ECM proteins, and introduces new advances in coating fabrication. These ECM coatings are effective in improving the biocompatibility of vascular grafts.

Characterization of an Innovative Biomaterial Derived From Human Wharton’s Jelly as a New Promising Coating for Tissue Engineering Applications

The extracellular matrix (ECM) offers the opportunity to create a biomaterial consisting of a microenvironment with interesting biological and biophysical properties for improving and regulating cell functions. Animal-derived ECM are the most widely used as an alternative to human tissues that are of very limited availability. However, incomplete decellularization of these tissues presents a high risk of immune rejection and disease transmission. In this study, we present an innovative method to extract human ECM derived from the Wharton’s jelly (WJ-ECMaa) of umbilical cords as a novel biomaterial to be used in tissue engineering. WJ-ECMaa was very efficiently decellularized, suggesting its possible use in allogeneic conditions. Characterization of its content allowed the identification of type I collagen as its main component. Various other matrix proteins, playing an important role in cell adhesion and proliferation, were also detected. WJ-ECMaa applied as a surface coating was analyzed by fluorescent labeling and atomic force microscopy. The results revealed a particular arrangement of collagen fibers not previously described in the literature. This biomaterial also presented better cytocompatibility compared to the conventional collagen coating. Moreover, it showed adequate hemocompatibility, allowing its use as a surface with direct contact with blood. Application of WJ-ECMaa as a coating of the luminal surface of umbilical arteries for a use in vascular tissue engineering, has improved significantly the cellularization of this surface by allowing a full and homogeneous cell coverage. Taking these results together, our novel extraction method of human ECM offers a very promising biomaterial with many potential applications in tissue engineering such as the one presented direct in vascular tissue engineering. Further characterization of the composition and functionality will help explore the ways it can be used in tissue engineering applications, especially as a scaffold or a surface coating.

Combinatorial wound healing therapy using adhesive nanofibrous membrane equipped with wearable LED patches for photobiomodulation

Wound healing is the dynamic tissue regeneration process replacing devitalized and missing tissue layers. With the development of photomedicine techniques in wound healing, safe and noninvasive photobiomodulation therapy is receiving attention. Effective wound management in photobiomodulation is challenged, however, by limited control of the geometrical mismatches on the injured skin surface. Here, adhesive hyaluronic acid-based gelatin nanofibrous membranes integrated with multiple light-emitting diode (LED) arrays are developed as a skin-attachable patch. The nanofibrous wound dressing is expected to mimic the three-dimensional structure of the extracellular matrix, and its adhesiveness allows tight coupling between the wound sites and the flexible LED patch. Experimental results demonstrate that our medical device accelerates the initial wound healing process by the synergetic effects of the wound dressing and LED irradiation. Our proposed technology promises progress for wound healing management and other biomedical applications.

Mesenchymal stem/stromal cell therapy in atopic dermatitis and chronic urticaria: immunological and clinical viewpoints

Allergic diseases are immune-mediated diseases. Allergies share a common immunopathogenesis, with specific differences according to the specific disease. Mesenchymal stem/stromal cells (MSCs) have been applied to people suffering from allergic and many other diseases. In this review, the immunologic roles of MSCs are systemically reviewed according to disease immunopathogenesis from a clinical viewpoint. MSCs seem to be a promising therapeutic modality not only as symptomatic treatments but also as causative and even preventive treatments for allergic diseases, including atopic dermatitis and chronic urticaria.

Functionalized Silk Vascular Grafts with Decellularized Human Wharton's Jelly Improves Remodeling via Immunomodulation in Rabbit Jugular Vein

Cell-free polymeric tissue-engineered vascular grafts (TEVGs) have shown great promise towards clinical translation; however, their limited bioactivity and remodeling ability challenge this cause. Here, a novel cell-free bioresorbable small diameter silk TEVG system functionalized with decellularized human Wharton's jelly (dWJ) matrix is developed and successfully implanted as interposition grafts into rabbit jugular vein. Implanted TEVGs remain patent for two months and integrate with host tissue, demonstrating neo-tissue formation and constructive remodeling. Mechanistic analysis reveals that dWJ matrix is a reservoir of various immunomodulatory cytokines (Interleukin-8, 6, 10, 4 and tumor necrosis factor alpha (TNF-α)), which aids in upregulating M2 macrophage-associated genes facilitating pro-remodeling behavior. Besides, dWJ treatment to human endothelial cells upregulates the expression of functional genes (cluster of differentiation 31 (CD31), endothelial nitric oxide synthase (eNOS), and vascular endothelial (VE)-cadherin), enables faster cell migration, and elevates nitric oxide (NO) production leading to the in situ development of endothelium. The dWJ functionalized silk TEVGs support increased host cell recruitment than control, including macrophages and vascular cells. It endows superior graft remodeling in terms of a dense medial layer comprising smooth muscle cells and elevates the production of extracellular matrix proteins (collagen and elastin). Altogether, these findings suggest that dWJ functionalization imitates the usefulness of cell seeding and enables graft remodeling.

Cellularized small-caliber tissue-engineered vascular grafts: looking for the ultimate gold standard

Due to the lack of efficacy of synthetic vascular substitutes in the replacement of small-caliber arteries, vascular tissue engineering (VTE) has emerged as a promising solution to produce viable small-caliber tissue-engineered vascular grafts (TEVG). Previous studies have shown the importance of a cellular intimal layer at the luminal surface of TEVG to prevent thrombotic events. However, the cellularization of a TEVG seems to be a critical approach to consider in the development of a TEVG. To date, no standard cellularization method or cell type has been established to create the ideal TEVG by promoting its long-term patency and function. In this review, advances in VTE are described and discussed with a particular focus on the construction approaches of cellularized small-caliber TEVGs, the cell types used, as well as their preclinical and clinical applications.

Systematic Review: Allogenic Use of Stromal Vascular Fraction (SVF) and Decellularized Extracellular Matrices (ECM) as Advanced Therapy Medicinal Products (ATMP) in Tissue Regeneration

Stromal vascular fraction (SVF) containing adipose stem cells (ASCs) has been used for many years in regenerative plastic surgery for autologous applications, without any focus on their potential allogenic role. Allogenic SVF transplants could be based on the possibility to use decellularized extracellular matrix (ECM) as a scaffold from a donor then re-cellularized by ASCs of the recipient, in order to develop the advanced therapy medicinal products (ATMP) in fully personalized clinical approaches. A systematic review of this field has been realized in accordance with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses-Protocols (PRISMA-P) guidelines. Multistep research of the PubMed, Embase, MEDLINE, Pre-MEDLINE, PsycINFO, CINAHL, Clinicaltrials.gov, Scopus database, and Cochrane databases has been conducted to identify articles and investigations on human allogenic ASCs transplant for clinical use. Of the 341 articles identified, 313 were initially assessed for eligibility on the basis of the abstract. Of these, only 29 met all the predetermined criteria for inclusion according to the PICOS (patients, intervention, comparator, outcomes, and study design) approach, and 19 have been included in quantitative synthesis (meta-analysis). Ninety-one percent of the studies previously screened (284 papers) were focused on the in vitro results and pre-clinical experiments. The allogenic use regarded the treatment of perianal fistulas, diabetic foot ulcers, knee osteoarthritis, acute respiratory distress syndrome, refractory rheumatoid arthritis, pediatrics disease, fecal incontinence, ischemic heart disease, autoimmune encephalomyelitis, lateral epicondylitis, and soft tissue defects. The information analyzed suggested the safety and efficacy of allogenic ASCs and ECM transplants without major side effects.

Tendon regeneration induced by umbilical cord graft in a rabbit tendon defect model

Whether tendon regeneration can be induced using the umbilical cord as a whole-graft structure is unknown. In this study, we explored the potential for tendon regeneration induction using an umbilical cord graft in a rabbit model of patella tendon defects. In 52 of 54 New Zealand White rabbits, the central third of the patella tendons of both hind legs was removed to create tendon defects. The rabbits were randomly divided into four groups, nonfilling (empty defect), refilling (defect refilled with resected tendon portion), Wharton's jelly (WJ) outside (WJO; defect filled with umbilical cord graft, WJ side facing outward), and WJ inside (WJI; same as WJO with WJ side facing inward) groups. Four rabbits from WJO and WJI groups were sacrificed for human CD 105 evaluation 1 month after surgery. Further histological, biomechanical, and gene expression analyses were performed at 3 and 6 months after surgery. The untreated patella tendons in the remaining two rabbits were harvested as normal biomechanical controls. Histological evaluation showed that the formed tissue structure fibers in the tendon defect area were much denser and more mature in the WJI group than in all other groups. Biomechanical testing showed that the failure load of the final tissue structure was the highest in the WJI group. Real-time polymerase chain reaction indicated that the expression of most tendon-related genes was upregulated in the WJI group at 6 months after surgery. We concluded that umbilical cord grafting induces effective tendon regeneration, particularly when the WJ side faces inward.

Kidney regeneration approaches for translation

The increase in the incidence of chronic kidney diseases that progress to end-stage renal disease has become a significant health problem worldwide. While dialysis can maintain and prolong survival, the only definitive treatment that can restore renal function is transplantation. Unfortunately, many of these patients die waiting for transplantable kidneys due to the severe shortage of donor organs. Tissue engineering and regenerative medicine approaches have been applied in recent years to develop viable therapies that could provide solutions to these patients. Cell-based and cell-free approaches have been proposed to address the challenges associated with chronic kidney diseases. Strategies and progress toward developing alternative therapeutic options will be reviewed.

A silk fibroin/decellularized extract of Wharton's jelly hydrogel intended for cartilage tissue engineering

A hybrid hydrogel was obtained from decellularized extract from Wharton's jelly (DEWJ) and silk fibroin (SF) and characterized for cartilage tissue engineering. Wharton's jelly was used due to its similarity with articular cartilage in extracellular matrix composition. Also, silk fibroin has good mechanical properties which make this construct appropriate for cartilage repair. Decellularization of Wharton's jelly was verified by DAPI staining, DNA quantification, and PCR analysis. Then, the biochemical composition of DEWJ was determined by ELISA kits for total proteins, collagens, sulfated glycosaminoglycans (sGAG), and transforming growth factor β1 (TGF-β1). After fabricating pure SF and SF/DEWJ hybrid hydrogels, their physical and mechanical properties were characterized by FESEM, Fourier-transform infrared spectroscopy (FTIR) and rheological assays (amplitude and frequency sweeps). Furthermore, cell viability and proliferation were assessed by MTT assay. The results have shown that DEWJ in hybrid hydrogels enhances mechanical properties of the construct relative to pure SF hydrogels. Also, this extract at its 40% concentration in culture media and 20% or 40% concentrations in SF/DEWJ hybrid hydrogels significantly increases population of the cells compared to control and pure SF hydrogel after 7 days. In conclusion, this study proposes the potential of SF/DEWJ hybrid hydrogels for cartilage tissue engineering applications.

Tissue-Engineered Grafts from Human Decellularized Extracellular Matrices: A Systematic Review and Future Perspectives

Tissue engineering and regenerative medicine involve many different artificial and biologic materials, frequently integrated in composite scaffolds, which can be repopulated with various cell types. One of the most promising scaffolds is decellularized allogeneic extracellular matrix (ECM) then recellularized by autologous or stem cells, in order to develop fully personalized clinical approaches. Decellularization protocols have to efficiently remove immunogenic cellular materials, maintaining the nonimmunogenic ECM, which is endowed with specific inductive/differentiating actions due to its architecture and bioactive factors. In the present paper, we review the available literature about the development of grafts from decellularized human tissues/organs. Human tissues may be obtained not only from surgery but also from cadavers, suggesting possible development of Human Tissue BioBanks from body donation programs. Many human tissues/organs have been decellularized for tissue engineering purposes, such as cartilage, bone, skeletal muscle, tendons, adipose tissue, heart, vessels, lung, dental pulp, intestine, liver, pancreas, kidney, gonads, uterus, childbirth products, cornea, and peripheral nerves. In vitro recellularizations have been reported with various cell types and procedures (seeding, injection, and perfusion). Conversely, studies about in vivo behaviour are poorly represented. Actually, the future challenge will be the development of human grafts to be implanted fully restored in all their structural/functional aspects.

hWJECM-Derived Oriented Scaffolds with Autologous Chondrocytes for Rabbit Cartilage Defect Repairing

Previously, we synthesized an articular cartilage extracellular matrix (ECM)-derived oriented scaffold for cartilage tissue engineering, which was biomimetic in terms of structure and biochemical composition. However, the limit resource of the cartilage-derived ECM is a hindrance for its application. In this study, we developed a new material for cartilage tissue engineering-human umbilical cord Wharton's jelly-derived ECM (hWJECM). The hWJECM has an abundant resource and similar biochemistry with cartilage ECM, and the use of it is not associated with ethical controversy. We adopted the method previously used in cartilage ECM-derived oriented scaffold preparation to generate the oriented hWJECM-derived scaffold, and the scaffold properties were tested in vitro and in vivo. The three-dimensional scaffold has a porous and well-oriented structure, with a mean pore diameter of ∼104 μm. Scanning electron microscopy and cell viability staining results demonstrated that the oriented scaffold has good biocompatibility and cell alignment. In addition, we used functional autologous chondrocytes to seed the hWJECM-derived oriented scaffold and tested the efficacy of the cell-scaffold constructs to repair the full-thickness articular cartilage defect in a rabbit model. Defects of 4 mm diameter were generated in the patellar grooves of the femurs of both knees and were implanted with chondrocyte-scaffold constructs (group A) or scaffolds alone (group B); rabbits with untreated defects were used as a control (group C). Six months after surgery, all defects in group A were filled completely with repaired tissue, and most of which were hyaline cartilage. In contrast, the defects in group B were filled partially with repaired tissue, and approximately half of these repaired tissues were hyaline cartilage. The defects in group C were only filled with fibrotic tissue. Histological grading score of group A was lower than those of groups B and C. Quantification of glycosaminoglycan indicated that newly formed cartilage in group A rabbits was comparable with normal cartilage. In conclusion, hWJECM-derived oriented scaffolds loaded with autologous chondrocytes induced cartilage repair in rabbit knees, which was comparable with native cartilage in terms of macroscopic view, microstructure, and biochemical composition.

Engineering Cardiovascular Implant Surfaces to Create a Vascular Endothelial Growth Microenvironment

Cardiovascular disease (CVD) is generally accepted as the leading cause of morbidity and mortality worldwide, and an increasing number of patients suffer from atherosclerosis and thrombosis annually. To treat these disorders and prolong the sufferers' life, several cardiovascular implants have been developed and applied clinically. Nevertheless, thrombosis and hyperplasia at the site of cardiovascular implants are recognized as long-term problems in the practice of interventional cardiology. Here, we start this review from the clinical requirement of the implants, such as anti-hyperplasia, anti-thrombosis, and pro-endothelialization, wherein particularly focus on the natural factors which influence functional endothelialization in situ, including the healthy smooth muscle cells (SMCs) environment, blood flow shear stress (BFSS), and the extracellular matrix (ECM) microenvironment. Then, the currently available strategies on surface modification of cardiovascular biomaterials to create vascular endothelial growth microenvironment are introduced as the main topic, e.g., BFSS effect simulation by surface micro-patterning, ECM rational construction and SMCs phenotype maintain. Finally, the prospects for extending use of the in situ construction of endothelial cells growth microenvironment are discussed and summarized in designing the next generation of vascular implants.