Evaluation of alginate hydrogel encapsulated mesenchymal stem cell migration in horses.

The research study aimed to evaluate the effectiveness of using a specific type of marking on mesenchymal stem cells (MSCs) for osteoarthritis treatment in horses. The stem cells, encapsulated in a material called an alginate hydrogel, were implanted into horses to observe cell migration patterns and their retention at the site of the injury.

Overview of the Study

• The study was motivated by the need to improve osteoarthritis treatment approaches. Osteoarthritis is a debilitating disease defined by pain and decreased joint mobility. Treating this disease with implantations of MSCs has demonstrated promising outcomes, but maintaining the cells at the action site to increase their therapeutic potential has been challenging.
• Mesenchymal stem cells are multi-potent cells that can differentiate into a variety of cell types. These cells were marked with Qtracker® 655 nanocrystals and encapsulated in an alginate hydrogel – a water-based, biocompatible material often used in drug delivery and tissue engineering.
• After the treatment, ten radiocarpal joints underwent arthroscopic surgery to allow for the evaluation of MSC migration. The joints were segregated into two groups based on their treatment: one receiving free-labelled MSCs (GA) and the other receiving labelled MSCs in microcapsules (GB).

Methodology and Results

• Seven days post-lesion induction and cell implantation, tissue samples from two animals were collected, including from the lesion site and parts of the joint. These samples were processed for fluorescence microscopy.
• In addition, the synovial fluid of three animals was analyzed to study the distribution of the labelled MSCs in the joint fluid over time, at 3, 7, and 21 days after the cell application.
• The marking method facilitated the visualization of cells in several locations (cartilage, synovial membrane, joint fluid, and articular capsule); however, the cells were mostly found in the synovial membrane with a sparse presence at the lesion site.
• Scarcely, the labelled MSCs in microcapsules were observed in the synovial fluid, which could be related to the lower number of MSCs escaping from the microcapsule pores. This result was seen as positive, given that encapsulated stem cells can release healing factors over an extended period until the cells differentiate.

Implications of the Study

• The use of an alginate hydrogel for encapsulating MSCs, as shown in this study, might be an efficient strategy to increase the dwell time and therapeutic potential of the stem cells at the lesion site.
• The findings could be leveraged to refine stem cell therapies used in treating osteoarthritis in horses, potentially improving cell survival, proliferation, and migration.
• More broadly, the results could also inform the design of stem cell-based treatments for other diseases and species, optimizing cell delivery and harnessing the therapeutic potential stem cells offer.