Inhibition of blood vessel formation by a chondrocyte-derived extracellular matrix

Cornea-Specific Human Adipose Stem Cell-Derived Extracellular Matrix for Corneal Stroma Tissue Engineering

Utilizing tissue-specific extracellular matrices (ECMs) is vital for replicating the composition of native tissues and developing biologically relevant biomaterials. Human- or animal-derived donor tissues and organs are the current gold standard for the source of these ECMs. To overcome the several limitations related to these ECM sources, including the highly limited availability of donor tissues, cell-derived ECM offers an alternative approach for engineering tissue-specific biomaterials, such as bioinks for three-dimensional (3D) bioprinting. 3D bioprinting is a state-of-the-art biofabrication technology that addresses the global need for donor tissues and organs. In fact, there is a vast global demand for human donor corneas that are used for treating corneal blindness, often resulting from damage in the corneal stromal microstructure. Human adipose tissue is one of the most abundant tissues and easy to access, and adipose tissue-derived stem cells (hASCs) are a highly advantageous cell type for tissue engineering. Furthermore, hASCs have already been studied in clinical trials for treating corneal stromal pathologies. In this study, a corneal stroma-specific ECM was engineered without the need for donor corneas by differentiating hASCs toward corneal stromal keratocytes (hASC-CSKs). Furthermore, this ECM was utilized as a component for corneal stroma-specific bioink where hASC-CSKs were printed to produce corneal stroma structures. This cost-effective approach combined with a clinically relevant cell type provides valuable information on developing more sustainable tissue-specific solutions and advances the field of corneal tissue engineering.

Anti-Osteoarthritic Effects of Cartilage-Derived Extracellular Matrix in a Rat Osteoarthritis Model

BACKGROUND

The extracellular matrix (ECM) has many functions, such as segregating tissues, providing support, and regulating intercellular communication. Cartilage-derived ECM (CECM) can be prepared via consecutive processes of chemical decellularization and enzyme treatment. The purpose of this study was to improve and treat osteoarthritis (OA) using porcine knee articular CECM.

METHODS

We assessed the rheological characteristics and pH of CECM solutions. Furthermore, we determined the effects of CECM on cell proliferation and cytotoxicity in the chondrocytes of New Zealand rabbits. The inhibitory effect of CECM on tumor necrosis factor (TNF)-α-induced cellular apoptosis was assessed using New Zealand rabbit chondrocytes and human synoviocytes. Finally, we examined the in vivo effects of CECM on inflammation control and cartilage degradation in an experimental OA-induced rat model. The rat model of OA was established by injecting monosodium iodoacetate into the intra-articular knee joint. The rats were then injected with CECM solution. Inflammation control and cartilage degradation were assessed by measuring the serum levels of proinflammatory cytokines and C-telopeptide of type II collagen and performing a histomorphological analysis.

RESULTS

CECM was found to be biocompatible and non-immunogenic, and could improve cell proliferation without inducing a toxic reaction. CECM significantly reduced cellular apoptosis due to TNF-α, significantly improved the survival of cells in inflammatory environments, and exerted anti-inflammatory effects.

CONCLUSION

Our findings suggest that CECM is an appropriate injectable material that mediates OA-induced inflammation.

Netrin-1 Secreted by Human Osteoarthritic Articular Chondrocytes Promotes Angiogenesis in Vitro

OBJECTIVE

Netrin-1 expression in articular cartilage is correlated with osteoarthritic changes. We aimed to investigate the contribution of Netrin-1 secreted by human osteoarthritic articular chondrocytes to angiogenesis process in vitro.

DESIGN

Human articular chondrocytes were extracted from non-osteoarthritic (n = 10) and osteoarthritic (n = 22) joints obtained from surgical specimens and incubated for 24 hours. Medium conditioned by non-osteoarthritic and osteoarthritic articular chondrocytes were collected. Human umbilical vein endothelial cells (HUVEC) were treated with control and conditioned medium and assessed using assays for cell adherence, migration, and tube formation. Netrin-1 expression and secretion was compared between non-osteoarthritic and osteoarthritic chondrocytes by qPCR, Western blot, and ELISA. The role of chondrocyte-secreted Netrin-1 on HUVEC functions was assessed by immunological neutralization using an anti-Netrin-1 monoclonal antibody.

RESULTS

As compared with medium conditioned by non-osteoarthritic chondrocytes, medium conditioned by osteoarthritic chondrocytes permitted tube formation by HUVEC. Both non-osteoarthritic and osteoarthritic chondrocytes expressed Netrin-1 at the RNA and protein levels. At the RNA level, Netrin-1 expression did not differ between non-osteoarthritic and osteoarthritic chondrocytes. At the protein level, Netrin-1 appeared as a full protein of 64 kDa in non-osteoarthritic chondrocytes and as two cleaved proteins of 55 kDa and 64 kDa in osteoarthritic chondrocytes. Immunological neutralization of endogenous Netrin-1 reduced the pro-angiogenic and pro-inflammatory transcriptional profile of HUVEC treated with the medium conditioned by osteoarthritic chondrocytes, as well as their capacities to form tubes.

CONCLUSIONS

Medium conditioned by osteoarthritic chondrocytes permits tube formation by HUVEC in vitro. This permissive effect is mediated by Netrin-1.

Bioink with cartilage-derived extracellular matrix microfibers enables spatial control of vascular capillary formation in bioprinted constructs

Microvasculature is essential for the exchange of gas and nutrient for most tissues in our body. Some tissue structures such as the meniscus presents spatially confined blood vessels adjacent to non-vascularized regions. In biofabrication, mimicking the spatial distribution of such vascular components is paramount, as capillary ingrowth into non-vascularized tissues can lead to tissue matrix alterations and subsequent pathology. Multi-material 3D bioprinting can potentially resolve anisotropic tissue features, although building complex constructs comprising stable vascularized and non-vascularized regions remains a major challenge. Here, we developed endothelial cell(EC)-laden pro- and anti-angiogenic bioinks, supplemented with bioactive matrix-derived microfibers (MFs) that were created from type I collagen sponges (col-1) and cartilage decellularized extracellular matrix (CdECM). EC-driven capillary network formation started two days after bioprinting. Supplementing cartilage-derived MFs to endothelial-cell laden bioinks reduced the total length of neo-microvessels by 29% after 14 days, compared to col-1 MFs-laden bioinks. As a proof of concept, the bioinks were bioprinted into an anatomical meniscus shape with a biomimetic vascularized outer and non-vascularized inner region, using a microgel suspension bath. The constructs were cultured up to 14 days, with in the outer zone the HUVEC-, mural cell-, and col-1 MF-laden pro-angiogenic bioink, and in the inner zone a meniscus progenitor cell (MPC)- and CdECM MF-laden anti-angiogenic bioink, revealing successful spatial confinement of the nascent vascular network only in the outer zone. Further, to co-facilitate both microvessel formation and MPC-derived matrix formation, we formulated cell culture medium conditions with a temporal switch. Overall, this study provides a new strategy that could be applied to develop zonal biomimetic meniscal constructs. Moreover, the use of ECM-derived MFs to promote or inhibit capillary networks opens new possibilities for the biofabrication of tissues with anisotropic microvascular distribution. These have potential for many applications including in vitro models, cancer progression, and testing anti-angiogenic therapies.

Anti-adhesive effect of chondrocyte-derived extracellular matrix surface-modified with poly-L-lysine (PLL)

After an injury, soft tissue structures in the body undergo a natural healing process through specific phases of healing. Adhesions occur as abnormal attachments between tissues and organs through the formation of blood vessels and/or fibrinous adhesions during the regenerative repair process. In this study, we developed an adhesion-preventing membrane with an improved physical protection function by modifying the surface of chondrocyte-derived extracellular matrices (CECM) with anti-adhesion function. We attempted to change the negative charge of the CECM surface to neutral using poly-L-lysine (PLL) and investigated whether it blocked fibroblast adhesion to it and showed an improved anti-adhesion effect in animal models of tissue adhesion. The surface of the membrane was modified with PLL coating (PLL 10), which neutralized the surface charge. We confirmed that the surface characteristics except for the potential difference were maintained after the modification and tested cell attachment in vitro. Adhesion inhibition was identified in a peritoneal adhesion animal model at 1 week and in a subcutaneous adhesion model for 4 weeks. N-CECM suppressed fibroblast and endothelial cell adhesion in vitro and inhibited abdominal adhesions in vivo. The CECM appeared to actively inhibit the infiltration of endothelial cells into the injured site, thereby suppressing adhesion formation, which differed from conventional adhesion barriers in the mode of action. Furthermore, the N-CECM remained intact without degradation for more than four weeks in vivo and exerted anti-adhesion effects for a long time. This study demonstrated that PLL10 surface modification rendered a neutral charge to the polymer on the extracellular matrix surface, thereby inhibiting cell and tissue adhesion. Furthermore, this study suggests a means to modify extracellular matrix surfaces to meet the specific requirements of the target tissue in preventing post-surgical adhesions. This article is protected by copyright. All rights reserved.

Effect of glutaraldehyde-crosslinked cartilage acellular matrix film on anti-adhesion and nerve regeneration in a rat sciatic nerve injury model

Decellularized extra-cellular matrix (ECM) has been studied as an alternative to anti-adhesive biomaterials and cartilage acellular matrix (CAM) has been shown to inhibit postoperative adhesion in several organs. This study aimed to evaluate the suitability of glutaraldehyde (GA) crosslinked CAM-films as anti-adhesion barriers for peripheral nerve injury. The films were successfully fabricated and showed improved physical properties such as mechanical strength, swelling ratio, and lengthened degradation period while maintaining the microstructure and chemical composition after GA crosslinking. In the in vitro study of CAM-film, the dsDNA content met the recommended limit of decellularization and more than 70% of the major ECM components were preserved after decellularization. The adhesion and proliferation of seeded human umbilical vein endothelial cells and fibroblasts were significantly lower in CAM-film than in control, but similar with Seprafilm. However, the CAM-film extract did not show cytotoxicity. In the in vivo study, the peri-neural fibrosis was thicker, adhesion score higher, and peri-neural collagen fibers more abundant in the control group than in the CAM-film group. The total number of myelinated axons was significantly higher in the CAM-film group than in the control group. The inflammatory marker decreased with time in the CAM-film group compared to that in the control group, whereas the nerve regenerative marker expression was maintained. Moreover, the ankle angles at contracture and toe-off were higher in the CAM film-treated rats than in the control rats. GA-crosslinked CAM films may be used during peripheral nerve surgery to prevent peri-neural adhesion and enhance nerve functional recovery.

Inhibitory Effect of Topical Cartilage Acellular Matrix Suspension Treatment on Neovascularization in a Rabbit Corneal Model

BACKGROUND

The extracellular matrix (ECM) of articular cartilage has an inhibitory effect on vascularization, yet clinical utilization has been technically challenging. In this study, we aimed to fabricate a biologically functional ECM powder suspension from porcine articular cartilage that inhibits neovascularization (NV).

METHODS

The digested-cartilage acellular matrix (dg-CAM) was prepared by sequential processes of decellularization, enzymatic digestion and pulverization. Physicochemical properties of dg-CAM were compared with that of native cartilage tissue (NCT). Cellular interactions between human umbilical vein endothelial cells (HUVECs) and dg-CAM was evaluated with proliferation, migration and tube formation assays compared with that of type I collagen (COL) and bevacizumab, an anti-angiogenic drug. We then investigated the therapeutic potential of topical administration of dg-CAM suspension on the experimentally induced rabbit corneal NV model.

RESULTS

The dg-CAM released a significantly larger amount of soluble proteins than that of the NCT and showed an improved hydrophilic and dispersion properties. In contrast, the dg-CAM contained a large amount of collagen, glycosaminoglycans and anti-angiogenic molecules as much as the NCT. The inhibitory effect on NV of the dg-CAM was more prominent than that of COL and even comparable to that of bevacizumab in inhibiting the HUVECs. The therapeutic potential of the dg-CAM was comparable to that of bevacizumab in the rabbit corneal NV model by efficiently inhibiting neovessel formation of the injured cornea.

CONCLUSION

The current study developed a dg-CAM having anti-angiogenic properties, together with water-dispersible properties suitable for topical or minimally invasive application for prevention of vessel invasion.

Decellularized Extracellular Matrix as a Potent Natural Biomaterial for Regenerative Medicine

Decellularization technique is a favorable method used to fabricate natural and tissue-like scaffolds. This technique is important because of its remarkable ability to perfectly mimic the natural extracellular matrix (ECM). ECM-based scaffolds/hydrogels provide structural support for cell differentiation and maturation. Therefore, novel natural-based bioinks, ECM-based hydrogels, and particulate forms of the ECM provide promising strategies for whole organ regeneration. Despite its efficacious characteristics, removal of residual detergent and the presence of various protocols make this technique challenging for scientists and regenerative medicine-related programs. This chapter reviews the most effective physical, chemical, and enzymatic protocols used to remove the cellular components and their challenges. We discuss the applications of decellularized ECM (dECM) in tissue engineering and regenerative medicine with an emphasis on hard tissues.

A Bioactive Cartilage Graft of IGF1-Transduced Adipose Mesenchymal Stem Cells Embedded in an Alginate/Bovine Cartilage Matrix Tridimensional Scaffold

Articular cartilage injuries remain as a therapeutic challenge due to the limited regeneration potential of this tissue. Cartilage engineering grafts combining chondrogenic cells, scaffold materials, and microenvironmental factors are emerging as promissory alternatives. The design of an adequate scaffold resembling the physicochemical features of natural cartilage and able to support chondrogenesis in the implants is a crucial topic to solve. This study reports the development of an implant constructed with IGF1-transduced adipose-derived mesenchymal stem cells (immunophenotypes: CD105⁺, CD90⁺, CD73⁺, CD14⁻, and CD34⁻) embedded in a scaffold composed of a mix of alginate/milled bovine decellularized knee material which was cultivated in vitro for 28 days (3CI). Histological analyses demonstrated the distribution into isogenous groups of chondrocytes surrounded by a de novo dense extracellular matrix with balanced proportions of collagens II and I and high amounts of sulfated proteoglycans which also evidenced adequate cell proliferation and differentiation. This graft also shoved mechanical properties resembling the natural knee cartilage. A modified Bern/O'Driscoll scale showed that the 3CI implants had a significantly higher score than the 2CI implants lacking cells transduced with IGF1 (16/18 vs. 14/18), representing high-quality engineering cartilage suitable for in vivo tests. This study suggests that this graft resembles several features of typical hyaline cartilage and will be promissory for preclinical studies for cartilage regeneration.

Preparation of a Cross-Linked Cartilage Acellular-Matrix Film and Its In Vivo Evaluation as an Antiadhesive Barrier

In this paper, a cartilage acellular-matrix (CAM) is chosen as a biomaterial for an effective antiadhesive barrier to apply between injured tissue and healthy tissues or organs. CAM is cross-linked using glutaraldehyde to create a cross-linked CAM (Cx-CAM) film. Cx-CAM has higher elastic modulus and toughness and more hydrophobic surface properties than CAM before cross-linking. Small intestinal submucosa (SIS), cross-linked SIS (Cx-SIS) as a negative control, and Seprafilm as a positive control are used in an experiment as adhesion barriers. Human umbilical vein endothelial cells (HUVECs) on SIS, Cx-SIS, or in a culture plate get attached and effectively proliferate for 7 days, but Cx-CAM and Seprafilm allow for little or no attachment and proliferation of HUVECs, thus manifesting antiadhesive and antiproliferative effects. In animals with surgical damage to the peritoneal wall and cecum, Cx-CAM and Seprafilm afford little adhesion and negligible inflammation after seven days, as confirmed by hematoxylin and eosin staining and macrophage staining, in contrast to an untreated-injury model, SIS, or Cx-SIS film. Cx-CAM significantly suppresses the formation of blood vessels between the peritoneal wall and cecum, as confirmed by CD31 staining. Overall, the newly designed Cx-CAM film works well as an antiadhesion barrier and has better anti-tissue adhesion efficiency.

Cross-linked electrospun cartilage acellular matrix/poly(caprolactone-co-lactide-co-glycolide) nanofiber as an antiadhesive barrier

In this work, we chose cartilage acellular matrix (CAM) as a promising antiadhesive material because CAM effectively inhibits the formation of blood vessels, and we used electrospinning to prepare antiadhesive barriers. Additionally, we synthesized N-hydroxysuccinimide (NHS)-poly(caprolactone-co-lactide-co-glycolide)-NHS (MP) copolymers (to tune degradation) as a cross-linking agent for CAM. This is the first report on the development of electrospun cross-linked (Cx) CAM/MP (CA/P) nanofiber (NF) (Cx-CA/P-NF) with a tunable degradation period as an antiadhesive barrier. Compared with the CA/P-NF before cross-linking, the electrospun Cx-CA/P-NF after cross-linking showed different biodegradation. Cx-CA/P-NF significantly inhibited the in vitro attachment and proliferation of human umbilical vein endothelial cells (HUVECs), as confirmed by an MTT assay and scanning electron microscopy images. Cx-CA/P-NFs implanted between a surgically damaged peritoneal wall and cecum gradually degraded in 7 days; this process was monitored by NIR imaging. The in vivo evaluation of the anti-tissue adhesive effect of Cx-CA/P-NFs revealed little adhesion, few blood vessels, and negligible inflammation at 7 days determined by hematoxylin and eosin staining. ED1 staining of Cx-CA/P-NFs showed infiltration of few macrophages because of the inflammatory response to the Cx-CA/P-NF as compared with an untreated injury model. Additionally, Cx-CA/P-NFs significantly suppressed the formation of blood vessels between the peritoneal wall and cecum, according to CD31 staining. Overall, Cx-CA/P-NFs yielded little adhesion, infiltration by macrophages, or formation of blood vessels in a postoperative antiadhesion assay. Thus, it is reasonable to conclude that the Cx-CA/P-NF designed herein successfully works as an antiadhesive barrier with a tunable degradation period.

STATEMENT OF SIGNIFICANCE

The cartilage acellular matrix (CAM) can inhibit the formation of fibrous tissue bridges and blood vessels between the tissue at an injured site and the surrounding healthy tissues. However, CAM has not been rigorously investigated as an antiadhesive barrier. In this manuscript, the cross-linked CAM nanofiber (Cx-CA/P-NF) designed herein successfully works as an antiadhesive barrier. Cx-CA/P-NFs yielded little adhesion, infiltration by macrophages, or formation of blood vessels in a postoperative antiadhesion assay. Moreover, we demonstrated the suitable properties of Cx-CA/P-NF such as easy cross-linking by maintaining the antiadhesive properties, controllable biodegradation, and in vivo antiadhesive effect of Cx-CA/P-NF.

Mechanically Reinforced Extracellular Matrix Scaffold for Application of Cartilage Tissue Engineering

Scaffolds with cartilage-like environment and suitable physical properties are critical for tissue-engineered cartilage repair. In this study, decellularized porcine cartilage-derived extracellular matrix (ECM) was utilized to fabricate ECM scaffolds. Mechanically reinforced ECM scaffolds were developed by combining salt-leaching and crosslinking for cartilage repair. The developed scaffolds were investigated with respect to their physicochemical properties and their cartilage tissue formation ability. The mechanically reinforced ECM scaffold showed similar mechanical strength to that of synthetic PLGA scaffold and expressed higher levels of cartilage-specific markers compared to those expressed by the ECM scaffold prepared by simple freeze-drying. These results demonstrated that the physical properties of ECM-derived scaffolds could be influenced by fabrication method, which provides suitable environments for the growth of chondrocytes. By extension, this study suggests a promising approach of natural biomaterials in cartilage tissue engineering.

Anti-inflammatory effect of hydroxyproline-GQDGLAGPK in desiccation stress-induced experimental dry eye mouse

The purpose of this study has been the investigation of the effect of novel peptide hydroxyproline-GQDGLAGPK (Hyp-GQDGLAGPK) in desiccation stress-induced dry eye mouse model and compared medicines for dry eye disease including cyclosporine, diquafosol and sodium hyaluronate. Seventy eight NOD.B10.H2^b mice were injected with scopolamine and exposed to an air draft for 10 days, and then the mice were treated with normal saline (n = 13), 1% Hyp-GQDGLAGPK (n = 13), 0.05% cyclosporine (n = 13), 3% diquafosol (n = 13), and 0.1% hyaluronate (n = 13) for 10 days. Thirteen mice were used for histopathologic analysis at DS 10d. The desiccation stress significantly decreased tear production, but the topical treatment of Hyp-GQDGLAGPK recovered to the baseline levels, which was similar to cyclosporine and diquafosol. In addition, Hyp-GQDGLAGPK improved facilitating epithelium stabilization including the corneal irregularity score, fluorescein score and detachment of the corneal epithelium. These improvements in stabilization of the corneal epithelium was superior to that in the cyclosporine and sodium hyaluronate groups. Furthermore, desiccation stress markedly induced expression of autoimmune inflammation-related factors in the lacrimal glands, but it was significantly suppressed by Hyp-GQDGLAGPK treatment. Overall, we found that novel peptide Hyp-GQDGLAGPK has multi-functional effects such as stabilizing the tear film and inhibiting inflammation.

Early detection of rheumatoid arthritis in rats and humans with 99mTc-3PRGD2 scintigraphy: imaging synovial neoangiogenesis

OBJECTIVES

To validate 99mTc-labeled arginylglycylaspartic acid (99mTc-3PRGD2) scintigraphy as a means to image synovial neoangiogenesis in joints afflicted by rheumatoid arthritis and to investigate its potential in the early detection and management of rheumatoid arthritis.

METHODS

Rheumatoid arthritis and osteoarthritis were generated in Sprague Dawley rats by type II collagen immunization and papain injection, respectively. Rats were imaged with 99mTc-3PRGD2 and 99mTc- methyl diphosphonate (99mTc MDP). X-ray images were also obtained and assessed by a radiologist. Immunohistochemistry of αvβ3 and CD31confirmed the onset of synovial neoangiogenesis. The effect of bevacizumab on rheumatoid arthritis was followed with 99mTc-3PRGD2 scintigraphy. A patient with rheumatoid arthritis and a healthy volunteer were scanned with 99mTc-3PRGD2.

RESULTS

Two weeks after immunization, a significant increase in 99mTc-3PRGD2 was observed in the joints of the rheumatoid arthritis model though uptake in osteoarthritis model and untreated controls was low. 99mTc-MDP whole body scans failed to distinguish early rheumatoid arthritis joints from healthy controls. The expression of αvβ3 and CD31was significantly higher in the joints of rheumatoid arthritis rats compared to normal controls. In serial 99mTc-3PRGD2 scintigraphy studies, 99mTc-3PRGD2 uptake increased in parallel with disease progression. Bevacizumab anti-angiogenetic therapy both improved the symptoms of the rheumatoid arthritis rats and significantly decreased 99mTc-3PRGD2 uptake. Significantly higher 99mTc-3PRGD2 accumulation was also observed in rheumatoid arthritis joints in the patient.

CONCLUSIONS

Our findings indicate that 99mTc-3PRGD2 scintigraphy could detect early rheumatoid arthritis by imaging the associated synovial neoangiogenesis, and may be useful in disease management.

Porous decellularized tissue engineered hypertrophic cartilage as a scaffold for large bone defect healing

Clinical translation of tissue engineered therapeutics is hampered by the significant logistical and regulatory challenges associated with such products, prompting increased interest in the use of decellularized extracellular matrix (ECM) to enhance endogenous regeneration. Most bones develop and heal by endochondral ossification, the replacement of a hypertrophic cartilaginous intermediary with bone. The hypothesis of this study is that a porous scaffold derived from decellularized tissue engineered hypertrophic cartilage will retain the necessary signals to instruct host cells to accelerate endogenous bone regeneration. Cartilage tissue (CT) and hypertrophic cartilage tissue (HT) were engineered using human bone marrow derived mesenchymal stem cells, decellularized and the remaining ECM was freeze-dried to generate porous scaffolds. When implanted subcutaneously in nude mice, only the decellularized HT-derived scaffolds were found to induce vascularization and de novo mineral accumulation. Furthermore, when implanted into critically-sized femoral defects, full bridging was observed in half of the defects treated with HT scaffolds, while no evidence of such bridging was found in empty controls. Host cells which had migrated throughout the scaffold were capable of producing new bone tissue, in contrast to fibrous tissue formation within empty controls. These results demonstrate the capacity of decellularized engineered tissues as 'off-the-shelf' implants to promote tissue regeneration.