Date of Award

12-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Bioengineering

Advisor

Mercuri, Jeremy J

Committee Member

Simionescu, Dan

Committee Member

Gill, Sanjitpal S

Abstract

Low back pain (LBP) is a significant burden with a lifetime prevalence of 84% and estimated expenditures of $85.9 billion.[1,2] Although LBP is multifactorial; it has been shown that LBP can originate from degenerating intervertebral discs (IVDs); a process which initiates in the nucleus pulposus (NP); a hydrated tissue primarily composed of type 2 collagen and proteoglycan. Current therapies for IVD degeneration (IDD) are palliative and merely delay surgical management. While these procedures may relieve pain temporarily, they fail to address the underlying cause of degeneration and make no attempt to regenerate the effected tissue. Additional concerns with the use of these treatments include the potential for accelerating degeneration in adjacent IVDs and that they are surgical strategies typically employed only during the late stages of IDD progression.[3–5] The purpose of this research was to develop a decellularization procedure to create a biomimetic NP scaffold for use in the early-stages of IDD, which may assist in mitigating, halting or reversing the progression of degeneration. The objectives of this research were to: (1) develop a procedure to decellularize healthy bovine caudal NPs to eliminate xenogeneic cellular remnants while retaining type 2 collagen and glycosaminoglycan content, (2) evaluate the resultant scaffolds mechanical properties, and (3) evaluate the cytocompatiblity of the scaffold with human amniotic membrane derived mesenchymal stem cells (hAMSCs). Results illustrate our ability to remove greater than 93% of bovine DNA (with no residual base-pairs present). Concomitantly, greater than 200μg of glycosaminoglycan (GAG) per milligram of sample dry weight was maintained. Furthermore measurement of hydroxyproline (HYP) content within NP scaffolds demonstrated a GAG:HYP ratio of 15:1, which is comparable to values reported for healthy human NP.[6] Histological and macroscopic evaluations of the scaffold illustrate a GAG-rich matrix, which closely resembles the human NP and no presence of cells within the scaffold, thus the scaffold was referred to as an acellular bovine NP (ABNP) scaffold. Mechanical evaluations of this ABNP scaffold yielded viscoelastic properties similar to a healthy human native NP.[7–9] Lastly, evaluation of the cytocompatibility has been performed and has proven the ability of the ABNP scaffold to maintain cell viability at 95% up to fourteen days. The results of this research indicate a promising scaffold for further analysis for the treatment of IDD.

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