Small-Diameter Subchondral Drilling Improves DNA and Proteoglycan Content of the Cartilaginous Repair Tissue in a Large Animal Model of a Full-Thickness Chondral Defect

Rate of Conversion to Matrix-Induced Autologous Chondrocyte Implantation After a Biopsy: A Multisurgeon Study

Background

Autologous chondrocyte implantation (ACI) and matrix-induced autologous chondrocyte implantation (MACI) are performed to treat focal chondral defects (FCDs); both are 2-step procedures involving a biopsy, followed by transplantation. There is little published research evaluating ACI/MACI in patients who undergo a biopsy alone.

Purpose

To determine (1) the value of ACI/MACI cartilage biopsies and concomitant procedures in patients with FCDs of the knee and (2) the conversion rate to cartilage transplantation as well as the rate of reoperation.

Study Design

Case series; Level of evidence, 4.

Methods

A retrospective review was performed of 46 patients (63% female) who underwent a MACI (or ACI) biopsy between January 2013 and January 2018. Preoperative data, intraoperative data, and postoperative outcomes were assessed at a minimum of 2 years after the biopsy. The conversion rate from a biopsy to transplantation and the reoperation rate were calculated and analyzed.

Results

Among the 46 patients included, 17 (37.0%) underwent subsequent surgery, with only 12 undergoing cartilage restoration surgery, for an overall transplantation rate of 26.1%. Of these 12 patients, 9 underwent MACI/ACI, 2 underwent osteochondral allograft transplantation (OCA), and 1 underwent particulated juvenile articular cartilage implantation at 7.2 ± 7.5 months after the biopsy. The reoperation rate was 16.7% (1 patient after MACI/ACI and 1 patient after OCA) at 13.5 ± 2.3 months after transplantation.

Conclusion

Arthroscopic surgery with debridement, chondroplasty, loose body removal, meniscectomy/meniscal repair, and other treatment approaches of knee compartment abnormalities at the time of a biopsy appeared to be sufficient in improving function and reducing pain in patients with knee FCDs.

Double membrane platelet-rich fibrin (PRF) - Synovium succeeds in regenerating cartilage defect at the knee: An experimental study on rabbit

Background

This study aims to prove the healing results (regeneration) in cartilage defects using a combination treatment of microfractures and transplantation synovium-platelet rich fibrin (S-PRF).

Methods

A cartilage defect was made in the trochlear groove of the knee of adult New Zealand white rabbits, and was classified into three treatment groups. The group 1 was cartilage defect without treatment, 2 with microfracture treatment, and 3 with microfracture covered with a synovium-platelet rich fibrin (S-PRF) membrane. Twelve weeks after the intervention, the animals were macroscopically and histologically examined, and evaluated by the International Cartilage Repair Society (ICRS). Additionally, the expression of aggrecan and type 2 collagen was examined by real-time-PCR.

Results

The ICSR scores for macroscopic were significantly higher in the microfracture and S-PRF transplant group than in the other groups. Also, the ICSR scores for histology were significantly higher in this group. The expression of aggrecan and type 2 collagen was higher in the group that received complete treatment.

Conclusions

Microfractures and transplantation of synovium-platelet rich fibrin (S-PRF) can regenerate knee cartilage defects which have been shown to increase the expression of mRNA aggrecan and mRNA type 2 collagen resulting in excellent repair.

Decellularized Wharton Jelly Implants Do Not Trigger Collagen and Cartilaginous Tissue Production in Tracheal Injury in Rabbits

BACKGROUND

Tracheal lesions are pathologies derived from the most diverse insults that can result in a fatal outcome. Despite the number of techniques designed for the treatment, a limiting factor is the extent of the extraction. Therefore, strategies with biomaterials can restructure tissues and maintain the organ's functionality, like decellularized Wharton's jelly (WJ) as a scaffold. The aim is to analyze the capacity of tracheal tissue regeneration after the implantation of decellularized WJ in rabbits submitted to a tracheal defect.

METHODS

An in vivo experimental study was undertaken using twenty rabbits separated into two groups (n = 10). Group 1 submitted to a tracheal defect, group 2 tracheal defect, and implantation of decellularized WJ. The analyses were performed 30 days after surgery through immunohistochemistry.

RESULTS

Inner tracheal area diameter (p = 0.643) didn't show significance. Collagen type I, III, and Aggrecan highlighted no significant difference between the groups (both collagens with p = 0.445 and the Aggrecan p = 0.4).

CONCLUSION

The scaffold appears to fit as a heterologous implant and did not trigger reactions such as rejection or extrusion of the material into the recipient. However, these results suggested that although the WJ matrix presents several characteristics as a biomaterial for tissue regeneration, it did not display histopathological benefits in trachea tissue regeneration.

The potential utility of hybrid photo-crosslinked hydrogels with non-immunogenic component for cartilage repair

Finding a suitable biomaterial for scaffolding in cartilage tissue engineering has proved to be far from trivial. Nonetheless, it is clear that biomimetic approaches based on gelatin (Gel) and hyaluronic acid (HA) have particular promise. Herein, a set of formulations consisting of photo-polymerizable Gel; photo-polymerizable HA, and allogenic decellularized cartilage matrix (DCM), is synthesized and characterized. The novelty of this study lies particularly in the choice of DCM, which was harvested from an abnormal porcine with α-1,3-galactose gene knockout. The hybrid hydrogels were prepared and studied extensively, by spectroscopic methods, for their capacity to imbibe water, for their behavior under compression, and to characterize microstructure. Subsequently, the effects of the hydrogels on contacting cells (in vitro) were studied, i.e., cytotoxicity, morphology, and differentiation through monitoring the specific markers ACAN, Sox9, Coll2, and Col2α1, hypertrophy through monitoring the specific markers alkaline phosphatase (ALP) and Col 10A1. In vivo performance of the hydrogels was assessed in a rat knee cartilage defect model. The new data expand our understanding of hydrogels built of Gel and HA, since they reveal that a significant augmenting role can be played by DCM. The data strongly suggest that further experimentation in larger cartilage-defect animal models is worthwhile and has potential utility for tissue engineering and regenerative medicine.

The use of a novel deer antler decellularized cartilage-derived matrix scaffold for repair of osteochondral defects

Background

The physiologic regenerative capacity of cartilage is severely limited. Current studies on the repair of osteochondral defects (OCDs) have mainly focused on the regeneration of cartilage tissues. The antler cartilage is a unique regenerative cartilage that has the potential for cartilage repair.

Methods

Antler decellularized cartilage-derived matrix scaffolds (adCDMs) were prepared by combining freezing-thawing and enzymatic degradation. Their DNA, glycosaminoglycans (GAGs), and collagen content were then detected. Biosafety and biocompatibility were evaluated by pyrogen detection, hemolysis analysis, cytotoxicity evaluation, and subcutaneous implantation experiments. adCDMs were implanted into rabbit articular cartilage defects for 2 months to evaluate their therapeutic effects.

Results

AdCDMs were observed to be rich in collagen and GAGs and devoid of cells. AdCDMs were also determined to have good biosafety and biocompatibility. Both four- and eight-week treatments of OCDs showed a flat and smooth surface of the healing cartilage at the adCDMs filled site. The international cartilage repair society scores (ICRS) of adCDMs were significantly higher than those of controls (porcine dCDMs and normal saline) (p < 0.05). The repaired tissue in the adCDM group was fibrotic with high collagen, specifically, type II collagen.

Conclusions

We concluded that adCDMs could achieve excellent cartilage regeneration repair in a rabbit knee OCDs model. Our study stresses the importance and benefits of adCDMs in bone formation and overall anatomical reconstitution, and it provides a novel source for developing cartilage-regenerating repair materials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13036-021-00274-5.

rAAV-Mediated Human FGF-2 Gene Therapy Enhances Osteochondral Repair in a Clinically Relevant Large Animal Model Over Time In Vivo

BACKGROUND

Osteochondral defects, if left untreated, do not heal and can potentially progress toward osteoarthritis. Direct gene transfer of basic fibroblast growth factor 2 (FGF-2) with the clinically adapted recombinant adeno-associated viral (rAAV) vectors is a powerful tool to durably activate osteochondral repair processes.

PURPOSE

To examine the ability of an rAAV-FGF-2 construct to target the healing processes of focal osteochondral injury over time in a large translational model in vivo versus a control gene transfer condition.

STUDY DESIGN

Controlled laboratory study.

METHODS

Standardized osteochondral defects created in the knee joints of adult sheep were treated with an rAAV human FGF-2 (hFGF-2) vector by direct administration into the defect relative to control (reporter) rAAV-lacZ gene transfer. Osteochondral repair was monitored using macroscopic, histological, immunohistological, and biochemical methods and by micro-computed tomography after 6 months.

RESULTS

Effective, localized prolonged FGF-2 overexpression was achieved for 6 months in vivo relative to the control condition without undesirable leakage of the vectors outside the defects. Such rAAV-mediated hFGF-2 overexpression significantly increased the individual histological parameter "percentage of new subchondral bone" versus lacZ treatment, reflected in a volume of mineralized bone per unit volume of the subchondral bone plate that was equal to a normal osteochondral unit. Also, rAAV-FGF-2 significantly improved the individual histological parameters "defect filling,""matrix staining," and "cellular morphology" and the overall cartilage repair score versus the lacZ treatment and led to significantly higher cell densities and significantly higher type II collagen deposition versus lacZ treatment. Likewise, rAAV-FGF-2 significantly decreased type I collagen expression within the cartilaginous repair tissue.

CONCLUSION

The current work shows the potential of direct rAAV-mediated FGF-2 gene therapy to enhance osteochondral repair in a large, clinically relevant animal model over time in vivo.

CLINICAL RELEVANCE

Delivery of therapeutic (hFGF-2) rAAV vectors in sites of focal injury may offer novel, convenient tools to enhance osteochondral repair in the near future.

Repair of articular cartilage defect using adipose-derived stem cell-loaded scaffold derived from native cartilage extracellular matrix

The purpose of this study was to investigate the feasibility of adipose-derived stem cells (ADSCs) as the seed cells of cartilage tissue engineering. ADSCs were isolated from adipose tissue that was harvested under sterile conditions from the inguen fold of porcines and cultured in vitro. Acellular cartilage extracellular matrix (ACECM) scaffolds of pigs were then constructed. Moreover, inflammatory cells, as well as cellular and humoral immune responses, were detected using hematoxylin and eosin staining staining, immunohistochemical staining, and western blot analysis. The results showed that the cartilage complex constructed by ADSCs and ACECM through tissue engineering successfully repaired the cartilage defect of the pig knee joint. The in vivo repair experiment showed no significant difference between chondrocytes, ADSCs, and induced ADSCs, indicating that ADSCs do not require in vitro induction and have the potential for chondrogenic differentiation in the environment around the knee joint. In addition, pig-derived acellular cartilage scaffolds possess no obvious immune inflammatory response when used in xenotransplantation. ADSCs may serve as viable seed cells for cartilage tissue engineering.

Biological Evaluation of Acellular Cartilaginous and Dermal Matrixes as Tissue Engineering Scaffolds for Cartilage Regeneration

An acellular matrix (AM) as a kind of natural biomaterial is gaining increasing attention in tissue engineering applications. An acellular cartilaginous matrix (ACM) and acellular dermal matrix (ADM) are two kinds of the most widely used AMs in cartilage tissue engineering. However, there is still debate over which of these AMs achieves optimal cartilage regeneration, especially in immunocompetent large animals. In the current study, we fabricated porous ADM and ACM scaffolds by a freeze-drying method and confirmed that ADM had a larger pore size than ACM. By recolonization with goat auricular chondrocytes and in vitro culture, ADM scaffolds exhibited a higher cell adhesion rate, more homogeneous chondrocyte distribution, and neocartilage formation compared with ACM. Additionally, quantitative polymerase chain reaction (qPCR) indicated that expression of cartilage-related genes, including ACAN, COLIIA1, and SOX9, was significantly higher in the ADM group than the ACM group. Furthermore, after subcutaneous implantation in a goat, histological evaluation showed that ADM achieved more stable and matured cartilage compared with ACM, which was confirmed by quantitative data including the wet weight, volume, and contents of DNA, GAG, total collagen, and collagen II. Additionally, immunological assessment suggested that ADM evoked a low immune response compared with ACM as evidenced by qPCR and immunohistochemical analyses of CD3 and CD68, and TUNEL. Collectively, our results indicate that ADM is a more suitable AM for cartilage regeneration, which can be used for cartilage regeneration in immunocompetent large animals.

Scaffold-Mediated Gene Delivery for Osteochondral Repair

Osteochondral defects involve both the articular cartilage and the underlying subchondral bone. If left untreated, they may lead to osteoarthritis. Advanced biomaterial-guided delivery of gene vectors has recently emerged as an attractive therapeutic concept for osteochondral repair. The goal of this review is to provide an overview of the variety of biomaterials employed as nonviral or viral gene carriers for osteochondral repair approaches both in vitro and in vivo, including hydrogels, solid scaffolds, and hybrid materials. The data show that a site-specific delivery of therapeutic gene vectors in the context of acellular or cellular strategies allows for a spatial and temporal control of osteochondral neotissue composition in vitro. In vivo, implantation of acellular hydrogels loaded with nonviral or viral vectors has been reported to significantly improve osteochondral repair in translational defect models. These advances support the concept of scaffold-mediated gene delivery for osteochondral repair.