Tissue Engineering and Cell Therapy for Cartilage Repair: Preclinical Evaluation Methods

Tissue Engineering Construct for Articular Cartilage Restoration with Stromal Cells from Synovium vs. Dental Pulp-A Pre-Clinical Study

BACKGROUND/OBJECTIVES

Cartilage injuries and osteoarthritis are prevalent public health problems, due to their disabling nature and economic impact. Mesenchymal stromal cells (MSCs) isolated from different tissues have the immunomodulatory capacity to regulate local joint environment. This translational study aims to compare cartilage restoration from MSCs from the synovial membrane (SM) and dental pulp (DP) by a tissue-engineered construct with Good Manufacturing Practices.

METHODS

A controlled experimental study was conducted on fourteen miniature pigs, using scaffold-free Tissue Engineering Constructs (TECs) from DP and SM MSCs, with a 6-month follow-up. Total thickness cartilage defects were created in both hind knees; one side was left untreated and the other received a TEC from either DP (n = 7) or SM (n = 7). An MRI assessed the morphology using the MOCART scoring system, T2 mapping evaluated water, and collagen fiber composition, and histological analysis was performed using the ICRS-2 score.

RESULTS

The untreated group had a mean MOCART value of 46.2 ± 13.4, while the SM-treated group was 65.7 ± 15.5 (p < 0.05) and the DP-treated group was 59.0 ± 7.9 (n.s.). The T2 mapping indicated a mean value of T2 of 54.9 ± 1.9 for native cartilage, with the untreated group at 50.9 ± 2.4 (p < 0.05). No difference was found between the T2 value of native cartilage and the treated groups. The ICRS-2 mean values were 42.1 ± 14.8 for the untreated group, 64.3 ± 19.0 for SM (p < 0.05), and 54.3 ± 12.2 for DP (n.s.).

CONCLUSION

MRI and histological analysis indicated that TEC treatment led to superior cartilage coverage and quality compared to the defect group. TECs from SM demonstrated better results than the defect group in the histological assessment.

Quantitative MRI methods for the assessment of structure, composition, and function of musculoskeletal tissues in basic research and preclinical applications

Osteoarthritis (OA) is a disabling chronic disease involving the gradual degradation of joint structures causing pain and dysfunction. Magnetic resonance imaging (MRI) has been widely used as a non-invasive tool for assessing OA-related changes. While anatomical MRI is limited to the morphological assessment of the joint structures, quantitative MRI (qMRI) allows for the measurement of biophysical properties of the tissues at the molecular level. Quantitative MRI techniques have been employed to characterize tissues' structural integrity, biochemical content, and mechanical properties. Their applications extend to studying degenerative alterations, early OA detection, and evaluating therapeutic intervention. This article is a review of qMRI techniques for musculoskeletal tissue evaluation, with a particular emphasis on articular cartilage. The goal is to describe the underlying mechanism and primary limitations of the qMRI parameters, their association with the tissue physiological properties and their potential in detecting tissue degeneration leading to the development of OA with a primary focus on basic and preclinical research studies. Additionally, the review highlights some clinical applications of qMRI, discussing the role of texture-based radiomics and machine learning in advancing OA research.

Emerging Trends in Biodegradable Microcarriers for Therapeutic Applications

Microcarriers (MCs) are adaptable therapeutic instruments that may be adjusted to specific therapeutic uses, making them an appealing alternative for regenerative medicine and drug delivery. MCs can be employed to expand therapeutic cells. MCs can be used as scaffolds for tissue engineering, as well as providing a 3D milieu that replicates the original extracellular matrix, facilitating cell proliferation and differentiation. Drugs, peptides, and other therapeutic compounds can be carried by MCs. The surface of the MCs can be altered, to improve medication loading and release, and to target specific tissues or cells. Allogeneic cell therapies in clinical trials require enormous volumes of stem cells, to assure adequate coverage for several recruitment locations, eliminate batch to batch variability, and reduce production costs. Commercially available microcarriers necessitate additional harvesting steps to extract cells and dissociation reagents, which reduces cell yield and quality. To circumvent such production challenges, biodegradable microcarriers have been developed. In this review, we have compiled key information relating to biodegradable MC platforms, for generating clinical-grade cells, that permit cell delivery at the target site without compromising quality or cell yields. Biodegradable MCs could also be employed as injectable scaffolds for defect filling, supplying biochemical signals for tissue repair and regeneration. Bioinks, coupled with biodegradable microcarriers with controlled rheological properties, might improve bioactive profiles, while also providing mechanical stability to 3D bioprinted tissue structures. Biodegradable materials used for microcarriers have the ability to solve in vitro disease modeling, and are advantageous to the biopharmaceutical drug industries, because they widen the spectrum of controllable biodegradation and may be employed in a variety of applications.