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Updated: Jun 26, 2026
Isolation, Characterization, and Therapeutic Application of Extracellular Vesicles from Cultured Human Mesenchymal Stem Cells
Published on: September 23, 2022
The effect of delivery via narrow-bore needles on mesenchymal cells
Kapil Agashi1, David Y S Chau, Kevin M Shakesheff
1Division of Drug Delivery & Tissue Engineering, School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, UK.
Aims:
Recently, there have been numerous preclinical and human studies investigating the regenerative capacity of cell suspensions following their direct injection into a target organ: the fundamental parameters for successful (clinical) cell therapy. At present, limited data exist in the identification of factors important for the survival of these cells (i.e., morphology, viability and proliferation rates) during and following their ejection via narrow-bore needles.
Materials & Methods:
Primary murine mesenchymal stem cells (mMSCs) were isolated, expanded and processed into a concentrated cell suspension consisting of either HBSS or HBSS supplemented with the antioxidant n-acetyl-cysteine. This suspension was then ejected from a 10 microl Hamilton syringe, via a variety of bore-sized needles, at different ejection rates. Cell characteristics including viability, spreading and attachment, apoptosis and proliferative ability were then assessed.
Results:
Following manipulation within a syringe, a decrease in the viability and cell spreading of mMSCs and a concurrent increase in the production of the caspase-3 protein, an early regulatory event in apoptosis, occurs. These detrimental effects were found to be increased when the cells were left in the syringe chamber for increased periods of time, and were similar at 5 microl/min and 1 microl/min ejection rates. However, on increasing the needle bore diameter, a significant reduction in these characteristics was observed. By comparison, mMSCs that were left to stand at room temperature (18-20 degrees C), but were not manipulated within a syringe, showed a significantly greater viability compared with manipulated cells. However, cells kept at 4 degrees C demonstrated a decreased viability compared with manipulated cells. When the mMSC were incubated with n-acetyl-cysteine, a known antioxidant, no significant change in caspase-3 production or cell spreading was observed.
Conclusions:
This study highlights potential parameters, such as minimizing the time period the cells are within the syringe and the use of wider-bore needles, involved in maintaining the high viable cell density required for the delivery of cell suspensions for cell therapy applications.
Insights
Minimizing syringe time and using wider needles improves cell viability for cell therapy. These factors are crucial for maintaining high viable cell density during delivery.
Area of Science:
- Regenerative Medicine
- Cell Therapy
- Biotechnology
Background:
- Cell suspensions are investigated for regenerative capacity via direct organ injection.
- Limited data exists on factors affecting cell survival during needle ejection for cell therapy.
Purpose of the Study:
- To identify key parameters for maintaining cell viability and function during syringe-based delivery.
- To assess the impact of needle bore size and ejection rate on cell characteristics.
Main Methods:
- Murine mesenchymal stem cells (mMSCs) were processed into suspensions.
- Cells were ejected using various needle sizes and ejection rates.
- Viability, apoptosis, spreading, and proliferation were assessed.
Main Results:
- Syringe manipulation decreased mMSC viability and spreading, increasing apoptosis.
- Longer syringe dwell time and smaller needle bores exacerbated detrimental effects.
- Wider needle bores significantly reduced negative impacts on cell characteristics.
Conclusions:
- Minimizing cell dwell time in syringes is critical for cell therapy.
- Utilizing wider-bore needles enhances cell viability for delivery.
- These parameters are essential for achieving high viable cell density in cell suspensions.
