Date of Award
Master of Science (MS)
Dr. Jiro Nagatomi
Dr. Jeremy Mercuri
Dr. William RIchardson
Low back pain (LBP) affects approximately 12% of adults in the US, and of these cases, between 26 and 42% are caused by intervertebral disc degeneration (IVDD). Current treatment approaches for LBP and IVDD, such as medication and surgery, mainly focus on reliving pain and do not address current or future degeneration. As a result of reherniation, up to 15% of patients will need a second surgery. As a solution, the use of tissue engineering combining scaffolds and stem cells to regenerate the damaged structures has been proposed. There are several types of stem cells that have shown potential for regenerative treatments, primarily adipose and amnion derived mesenchymal stem cells. However, intervertebral disc (IVD) cells, specifically those in the nucleus pulposus, experience elevated pressures caused by supporting the mechanical loads applied to the spine and lower pH due to the avascular nature of the IVD, which could affect the viability of any stem cells that are placed in the IVD as part of a treatment.
The primary goals of the current research are to develop methods to create IVD conditions in vitro and to use these methods to evaluate how potential cell sources respond to these conditions. The specific aims were (1) To update a pressure-stretch bioreactor, (2) to evaluate hADMSCs response to pressure and pH conditions found in healthy and degenerated IVDs, and (3) to develop a new high-pressure bioreactor to create more realistic simulations of in vivo conditions
Strain quantification of the new pressure stretch bioreactor done via image analysis with ImageJ showed that the new design is capable of creating up to approximately a 14% strain. Using Caspase-1 activity as a indicator, it was also determined that pressure and stretch are being applied to MYP3 cells seeded on silicone membranes. Exposure of hADMSCs to healthy and degenerated IVD conditions (0.03 or 0.275MPa and 6.5 or 7.4 pH) for six days resulted in a decreased cell density compared to the control group and an altered cell morphology. Gradually changing the pH from 7.4 to 6.5 decreased the adverse effect of the pH change on cell number. Gradually increasing the pressure to 0.275 MPa did not have the same effect and still led to a drop in cell number. Initial qPCR results for NP and chondrogenic markers at different pressures and normal pH showed mostly elevated expression levels compared to the control group.
While there is decreased cell density, hADMSCs were able to survive in IVD-like conditions, and with additional studies, may be a viable option for tissue engineering. The new pressure-stretch bioreactor is ready for use in future urothelial studies or IVD studies and the high-pressure bioreactor is in the process of further development for use in pressure-cycling based studies.
Pendino, Alexandria, "Effects of IVD-Like Pressure and pH on Human Adipose Derived Mesenchymal Stem Cells" (2023). All Theses. 4152.