title: Simulation of biological therapies for degenerated intervertebral discs.
abstract: The efficacy of biological therapies on intervertebral disc repair was quantitatively studied using a three-dimensional finite element model based on a cell-activity coupled multiphasic mixture theory. In this model, cell metabolism and matrix synthesis and degradation were considered. Three types of biological therapies-increasing the cell density (Case I), increasing the glycosaminoglycan (GAG) synthesis rate (Case II), and decreasing the GAG degradation rate (Case III)-to the nucleus pulposus (NP) of each of two degenerated discs [one mildly degenerated (e.g., 80% viable cells in the NP) and one severely degenerated (e.g., 30% viable cells in the NP)] were simulated. Degenerated discs without treatment were also simulated as a control. The cell number needed, nutrition level demanded, time required for the repair, and the long-term outcomes of these therapies were analyzed. For Case I, the repair process was predicted to be dependent on the cell density implanted and the nutrition level at disc boundaries. With sufficient nutrition supply, this method was predicted to be effective for treating both mildly and severely degenerated discs. For Case II, the therapy was predicted to be effective for repairing the mildly degenerated disc, but not for the severely degenerated disc. Similar results were predicted for Case III. No change in cell density for Cases II and III were predicted under normal nutrition level. This study provides a quantitative guide for choosing proper strategies of biological therapies for different degenerated discs.
authors.affiliation: Department of Biomedical Engineering, Coral Gables, Florida.
authors.forename: Qiaoqiao
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, Florida.
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Orthopaedic Surgery, NOVA Southeastern University, Fort Lauderdale, Florida.
authors.forename: H Thomas
authors.initials: HT
authors.lastname: Temple
authors.affiliation: Department of Orthopaedics, University of Miami, Miami, Florida.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Brown
authors.affiliation: Department of Biomedical Engineering, Coral Gables, Florida.|Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, Florida.
authors.forename: Weiyong
authors.initials: W
authors.lastname: Gu
mesh_terms: D001691:Biological Therapy; D020342:Finite Element Analysis; D006025:Glycosaminoglycans / Q000096:biosynthesis; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000628:therapy*
chemical_list: D006025:Glycosaminoglycans
keywords: biomechanics; disc repair; finite element model