As reported on News Medical, researchers are increasingly exploring laboratory-grown organoids as potential tools for repairing damage caused by spinal cord and peripheral nerve injuries.
A review published in Engineering examines recent progress in developing spinal cord and peripheral nerve organoids and considers how these three-dimensional models could ultimately contribute to regenerative treatments for neurotrauma. The paper, Engineering Spinal Cord and Peripheral Nerve Organoids: Strategies for Construction and Potential Applications for Regenerative Medicine in Neurotrauma, was authored by Jiaqi Su, Zhiwen Yan, Xiaoxuan Tang, Tong Wu, Jue Ling and Yun Qian.
Building more realistic models of the nervous system
Organoids are three-dimensional cellular structures created from stem cells. Under appropriate laboratory conditions, the cells can organize into arrangements that reproduce certain structural and functional characteristics of human tissues.
That ability has made organoids valuable experimental platforms for studying disease mechanisms, evaluating potential therapies and investigating regenerative medicine strategies.
For spinal cord injury (SCI) and peripheral nerve injury (PNI), researchers hope that models incorporating multiple relevant cell types and tissue features could provide a better representation of the biological processes involved in injury and recovery.
The review identifies several important considerations in constructing neural organoids, including the cells used to initiate growth, the molecular signals guiding their development and the materials that provide a three-dimensional environment.
Embryonic stem cells and induced pluripotent stem cells are among the possible starting materials. According to the authors, the cellular source can influence how successfully an organoid develops and responds to signals intended to direct its differentiation.
Controlling development through molecular signals
Scientists can manipulate signaling pathways to encourage cells within organoids to adopt particular identities and organizational patterns.
Among the pathways discussed in the review are transforming growth factor-beta (TGF-β), bone morphogenetic protein (BMP), WNT, fibroblast growth factor (FGF) and sonic hedgehog (SHH). Carefully regulating these signals can help produce organoids displaying specific characteristics of nervous system development.
For example, researchers have developed approaches designed to reproduce dorsal and ventral characteristics of the spinal cord. Targeted molecular signaling can also be used to generate organoids representing dorsal root ganglia, structures involved in transmitting sensory information through the peripheral nervous system.
Finding better materials for 3D growth
The environment surrounding developing cells is another significant consideration.
Three-dimensional culture matrices provide physical support while supplying biochemical and mechanical signals that can influence cell survival, organization and differentiation. Matrigel has been widely used for this purpose, but concerns surrounding variability and possible immune responses have encouraged investigation of other materials.
Among the alternatives highlighted in the review are decellularized extracellular matrix materials and engineered hydrogels, which could offer researchers additional ways to control the conditions in which organoids develop.
Potential applications extend beyond disease modeling
The possible role of neural organoids may eventually extend from laboratory research to regenerative medicine.
The authors discuss several potential applications, including transplantation-based cell therapies, tissue engineering approaches and extracellular vesicles produced by organoids. These vesicles are being investigated for their possible role in supporting neural repair.
Organoid transplantation is of particular interest because these structures can contain multiple interacting cell populations rather than a single isolated cell type. After transplantation, those cells could potentially respond to signals in the surrounding injured tissue and undergo further differentiation or maturation.
Such characteristics suggest organoids could eventually offer new strategies for addressing the biological complexity of spinal cord and peripheral nerve damage.
Significant barriers remain
Despite encouraging progress, neural organoids are not yet complete replicas of the human nervous system.
The review identifies substantial variability among organoids as one challenge. Current models may also reproduce only part of the functionality of the tissues they are intended to represent.
Developing realistic blood vessel networks and recreating the immune environment surrounding neural tissue remain additional obstacles. Both factors are particularly important when considering organoids for regenerative applications in living patients.
Addressing these limitations will be essential before laboratory advances can be translated into dependable clinical therapies.
A promising platform for neurotrauma research
Overall, the review presents spinal cord and peripheral nerve organoids as an emerging platform with applications spanning disease modeling, therapeutic research and regenerative medicine.
Continued improvements in stem-cell selection, developmental signaling and three-dimensional culture materials could enable scientists to create increasingly sophisticated models of nervous system tissue. In turn, those advances may provide researchers with new ways to investigate spinal cord and peripheral nerve repair and potentially lay the groundwork for future treatments.
