Intervertebral disc (IVD) degeneration occurs with aging, leading to low back pain (LBP), which is one of the leading conditions of disability worldwide. With the lack of effective treatment, decellularized extracellular matrix (dECM) – based biomaterials have been proposed for IVD regeneration. However, the impact of donor ages on tissue repair had never been explored before in the disc field. Therefore, we aimed to address this question.

For that, a decellularization protocol for bovine nucleus pulposus (NP) of different aged donors (fetus, young and old) was optimized by testing several detergents (SDS and Triton). The process efficiency was evaluated in terms of DNA and cell removal, as well as ECM preservation. Afterwards, dECMs were repopulated with bovine NP cells and cultured ex vivo. At day 7, cell behavior, ECM de novo synthesis and remodeling were evaluated [1]. Moreover, dECMs’ inflammatory response was assessed after in vivo CAM assay. Finally, inflammatory and angiogenic cytokines were analyzed in the conditioned media-derived from dECMs by using a cytokine array.

As results, an optimal decellularization protocol (SDS 0.1%, 1h), efficient at removing cells and DNA from bovine NPs, while preserving ECM cues of native tissues, was developed. After repopulation, aggrecan increased in younger NPs, while collagen 2 decreased which may be indicative of matrix remodeling [1]. After in vivo CAM assay, fetal dECMs showed the highest inflammatory response. Finally, no statistically significant changes of cytokines were detected in the matrices, despite for a trend of higher IFN-α, IFN-γ and LIF in fetal dECMs, IL-1β in young dECMs and Decorin in old dECMs.

Overall, this work uncovered the importance of tissue donor ages for tissue regenerative purpose, opening new avenues for the development of appropriate therapeutic strategies for IVD degeneration.

Acknowledgments: FCT, EUROSPINE, ON Foundation.

The potential of piezoelectric biomaterials for bone tissue engineering is demonstrated. This work proves that the use of piezoelectric poly(vinylidene fluoride) (PVDF), able to provide electrical stimuli upon mechanical solicitation to the growing bone cells, enhances the bone regeneration in vivo. Poled and non-poled PVDF films, with and without macroscopic piezoelectric response, respectively and randomly oriented piezoelectric electrospun fiber mats have been used as substitutes for bone to test their osteogenic properties in Wistar rats by analyzing new bone formation in 3 mm bilateral femur defects in vivo. After 4 weeks, the qualification of the regenerated bone was performed according the H&E staining. Defect implanted with poled PVDF films demonstrated significantly more defect closure and bone remodeling, showing the large potential of piezoelectric biomaterials for bone repair, as well as for other electromechanical responsive tissues such as muscle and tendon.