Understanding the molecular biology of intervertebral disc degeneration and potential gene therapy strategies for regeneration: a review

Intervertebral disc degeneration (IVDD) is a multi-factorial process characterized by phenotypic and genotypic changes, which leads to low back pain and disability. Prolonged imbalance between anabolism and catabolism in discs alters their composition resulting in progressive loss of proteoglycans and hydration leading to IVDD. The current managements for IVDD are only able to relieve the symptoms but do not address the underlying pathology of degeneration. Researchers have tried to find out differences between the aging and degeneration of the disc. Intense attempts are in progress for identifying the various factors responsible for disc degeneration, as well as strategies for regeneration. Recently biological approaches have gained thrust in the field of IVDD. The present review illustrates the current understanding of intervertebral disc degeneration and aims to put forth recent advancements in regeneration strategies involving different biological therapies such as growth factor, cell, and gene therapy. The potentials and consequences of these therapies are also extensively discussed along with citing the most suitable method, that is, the gene therapy in detail. Initially, gene therapy was mediated by viral vectors but recent progress has enabled researchers to opt for non-virus-mediated gene therapy methods, which ensure that there are no risks of mutagenicity and infection in target cells. With constant efforts, non-virus-mediated gene therapy may prove to be an extremely powerful tool in treatment of IVDD in future.