Crosstalk between Autophagy and Apoptosis in Intervertebral Disc Degeneration

Objective: To describe the relationship between autophagy and apoptosis and the possible signaling pathways involved in degenerative lumbar intervertebral disc. Summary of Background Data: Autophagy and apoptosis are regulatory cellular mechanisms that determine many pathologies, including degenerative intervertebral disc disease. The interactions between these events in the damage or protection of intervertebral disc cells and in cellular homeostasis remain controversial. Methods: The sample size was twenty patients who underwent lumbar spine surgery for symptomatic disc herniation or spondylolisthesis. Intervertebral discs were classified by magnetic resonance as Pfirrmann grade IV and grade V. Six patients were operated on two levels, resulting in twenty-six intervertebral discs that were submitted to immunohistochemistry to verify the protein expression of autophagy and apoptosis markers. Results: The autophagic markers had greater protein expression in the human intervertebral disc (Pfirrmann Grades IV and V). Under these conditions, autophagy and apoptosis showed a negative correlation. Regarding apoptosis, caspase 8 presented the highest protein expression, which allows inferring the preference for the extrinsic pathway in cell death. Conclusions: Autophagy had the greatest protein expression negative profile compared to apoptosis. Caspase 8 had the highest protein expression in apoptosis.

Genotoxicity Clues to Predict Intervertebral Disc Degeneration: A Systematic Review

Objective: To characterize the association between DNA damage and Intervertebral disc degeneration (IDD). Summary of Background Data: IDD is the main disorder causing low back pain and is the most promising target for intervention. Many factors can contribute to the etiology, such as genetics, environment and lifestyle, but it is not yet fully understood. DNA damage can influence this process and needs to be studied, as well as the agents that can determine these damages. Methods: A systematic literature search of PubMed, Web of Science and Scopus was performed to identify studies related to DNA damage to the intervertebral disc. Results: After screening 61 records, 7 articles were included according to the selection criteria. All studies showed some relation between DNA damage and IDD. However, DNA damage was always considered a secondary issue to be investigated. Conclusions: Many factors can influence DNA damage induced by different genotoxic agents on the degenerative cascade of IVD. However, the correlation between IDD severity and DNA damage, as well as the factual role of DNA damage in disc degeneration could not be defined.