Fan He1, Ming Pei. 1. Stem Cell and Tissue Engineering Laboratory, Department of Orthopaedics, West Virginia University, Morgantown, West Virginia 26506-9196, USA.
Abstract
STUDY DESIGN: After plating for 6 passages on either plastic flasks or extracellular matrix (ECM) deposited by synovium-derived stem cells (SDSCs), expanded nucleus pulposus (NP) cells were evaluated for redifferentiation capacity. OBJECTIVE: The aim was to assess the feasibility of using ECM deposited by a tissue-specific stem cell to provide a 3-dimensional microenvironment for NP cell rejuvenation. SUMMARY OF BACKGROUND DATA: Autologous disc cell-based therapy is a promising approach for intervertebral disc regeneration. Unfortunately, the current in vitro expansion of NP cells in monolayer results in dedifferentiation of these cells. METHODS: Primary NP cells were plated on either plastic flasks or ECM for 6 consecutive passages. At each passage, cell numbers were counted for proliferation rate, cell phenotype was evaluated using flow cytometry, and cell differentiation status was assessed using real-time polymerase chain reaction (PCR). The pellets from expanded NP cells at passages 1, 4, and 6 were incubated in a serum-free defined medium for 14 days. Redifferentiation capacity of the expanded NP cells was evaluated using histology, biochemistry, and real-time PCR. RESULTS: NP cells expanded on ECM grew much faster with a smaller size and fibroblast-like shape compared with those on plastic flasks. ECM-treated NP cells acquired an enhanced CD90 expression and higher mRNA levels of types I, II, and X collagen and aggrecan, as well as a robust redifferentiation capacity, evidenced by dramatically increased type II collagen, aggrecan, and Sox9 and decreased type I collagen for up to 6 passages. CONCLUSION: SDSC-derived ECM can provide a tissue-specific microenvironment for the rejuvenation of NP cells with a higher proliferation rate and redifferentiation capacity. These characteristics may play a role in improving an autologous disc cell-based minimally invasive therapeutic approach toward physiological reconstruction of a biologically functional disc in the clinical setting.
STUDY DESIGN: After plating for 6 passages on either plastic flasks or extracellular matrix (ECM) deposited by synovium-derived stem cells (SDSCs), expanded nucleus pulposus (NP) cells were evaluated for redifferentiation capacity. OBJECTIVE: The aim was to assess the feasibility of using ECM deposited by a tissue-specific stem cell to provide a 3-dimensional microenvironment for NP cell rejuvenation. SUMMARY OF BACKGROUND DATA: Autologous disc cell-based therapy is a promising approach for intervertebral disc regeneration. Unfortunately, the current in vitro expansion of NP cells in monolayer results in dedifferentiation of these cells. METHODS: Primary NP cells were plated on either plastic flasks or ECM for 6 consecutive passages. At each passage, cell numbers were counted for proliferation rate, cell phenotype was evaluated using flow cytometry, and cell differentiation status was assessed using real-time polymerase chain reaction (PCR). The pellets from expanded NP cells at passages 1, 4, and 6 were incubated in a serum-free defined medium for 14 days. Redifferentiation capacity of the expanded NP cells was evaluated using histology, biochemistry, and real-time PCR. RESULTS: NP cells expanded on ECM grew much faster with a smaller size and fibroblast-like shape compared with those on plastic flasks. ECM-treated NP cells acquired an enhanced CD90 expression and higher mRNA levels of types I, II, and X collagen and aggrecan, as well as a robust redifferentiation capacity, evidenced by dramatically increased type II collagen, aggrecan, and Sox9 and decreased type I collagen for up to 6 passages. CONCLUSION: SDSC-derived ECM can provide a tissue-specific microenvironment for the rejuvenation of NP cells with a higher proliferation rate and redifferentiation capacity. These characteristics may play a role in improving an autologous disc cell-based minimally invasive therapeutic approach toward physiological reconstruction of a biologically functional disc in the clinical setting.