Immunohistochemical demonstration of advanced glycation end products and the effects of advanced glycation end products in ossified ligament tissues in vitro

Abstract

Study design: This study correlates advanced glycation end products with ossified ligament tissues of the cervical spine in vitro.

Objective: To investigate the effect of advanced glycation end products on ossification of the spinal ligaments in vitro.

Summary of background data: We have hypothesized that an accumulation of advanced glycation end products in the spinal ligament might result in some observable change in specific growth factors responsible for ossification in the spinal ligaments.

Methods: Samples of the posterior longitudinal and yellow ligaments were harvested from patients (n = 5) with ossification of the posterior longitudinal ligament, and analyzed for the presence of advanced glycation end products and their receptor advanced glycation end product receptor by immunohistochemistry. Real-time polymerase chain reaction (PCR) was used to quantify the messenger ribonucleic acid (mRNA) levels of bone morphogenetic protein (BMP)-2, BMP-7, alkaline phosphatase, an osteoblast-specific transcription factor 1 (Cbfa1), and osteocalcin from yellow ligament cells treated with advanced glycation end products.

Results: Immunohistochemical analysis revealed that advanced glycation end products and advanced glycation end product receptor were localized to within the posterior longitudinal and yellow ligaments. Advanced glycation end products were found to increase significantly the expression of BMP-2, BMP-7, Cbfa1, and osteocalcin at the mRNA levels after treatment with advanced glycation end products (1 microg/mL).

Conclusions: This is the first report to investigate the correlation, if any, between the ossified spinal ligament and advanced glycation end products. These results suggested that accumulation in advanced glycation end products and their interaction with advanced glycation end product receptor were 1 of the important risk factors in the process of ossification in the spinal ligaments.