Disclosures: Balaji V. Sridhar, MD, PhD: Nothing to disclose

Objective: To test the hypothesis that mesenchymal stem cell (MSC) viability can be improved after injection into lumbar facet joint space with the use of an injectable, biocompatible dynamically adaptable hydrogel network. This technique would improve upon current methods of injection in saline alone and will render stem cell therapies more reliable for treatment of degenerative conditions such as lumbar facet osteoarthritis.

Design: Basic biomedical engineering science project with appropriate controls to evaluate viability of cells after injection through a 26-gauge needle.

Setting: Bioengineering lab

Participants: Sprague Dawley Rat bone marrow derived MSCs were used in the experiments.

Interventions: Cells were either injected with saline or after encapsulation in a modified, injectable hyaluronic acid (HA) gel and were compared to viability of cells seeded at the same density. Rat MSCs were used after a third passage and were placed in 1 mL insulin syringes (BD Bioscience) before being injected through a 26-gauge needle on an untreated 24 well plate. 1 mL of low glucose DMEM media was added to the plate along with Live/Dead reagents after injection with either saline or with the HA material. Cell were injected at a rate of 1000 mL/ min.

Main Outcome Measures: Viability was measured via the Live/Dead assay (Life Technologies) and visualized with a fluorescent scope to quantify live cells and dead cells.

Results: Preliminary evidence shows that cells demonstrated higher viability (~96% ± 2%) when injected with the HA gel through a 26-gauge needle at 1000 mL/min compared to cells that were delivered with only saline (~70 % ± 4%).

Conclusions: Preliminary data suggest modified HA hydrogels can be used to protect stem cells during injection through small gauge needles to protect them from shear forces and increase their viability after injection. This would allow cells signal with greater potency at the injected site.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/a-novel-injectable-biomaterial-for-improved-stem-cell-delivery-for-treatment-of-lumbar-facet-osteoarthritis/