Enhancement of Energy Production of the Intervertebral Disc by the Implantation of Polyurethane Mass Transfer Devices.

Insufficient nutrient supply has been suggested to be one of the etiologies for intervertebral disc (IVD) degeneration. We are investigating nutrient transport into the IVD as a potential treatment strategy for disc degeneration. Most cellular activities in the IVD (e.g., cell proliferation and extracellular matrix production) are mainly driven by adenosine-5'-triphosphate (ATP) which is the main energy currency. The objective of this study was to investigate the effect of increased mass transfer on ATP production in the IVD by the implantation of polyurethane (PU) mass transfer devices. In this study, the porcine functional spine units were used and divided into intact, device and surgical groups. For the device and surgical groups, two puncture holes were created bilaterally at the dorsal side of the annulus fibrosus (AF) region and the PU mass transfer devices were only implanted into the holes in the device group. Surgical groups were observed for the effects of placing the holes through the AF only. After 7 days of culture, the surgical group exhibited a significant reduction in the compressive stiffness and disc height compared to the intact and device groups, whereas no significant differences were found in compressive stiffness, disc height and cell viability between the intact and device groups. ATP, lactate and the proteoglycan contents in the device group were significantly higher than the intact group. These results indicated that the implantation of the PU mass transfer device can promote the nutrient transport and enhance energy production without compromising mechanical and cellular functions in the disc. These results also suggested that compromise to the AF has a negative impact on the IVD and must be addressed when treatment strategies are considered. The results of this study will help guide the development of potential strategies for disc degeneration.