Bingjie Gao,1 Yizhi Cui,2 Yexiao Qin,2 Chuncheng Qu,3 Jiaqi Zhao,4 Xiaoning Li2 

1Second Clinical Medical School, Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang, People’s Republic of China; 2Department of Acupuncture, The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang, People’s Republic of China; 3School of Basic Medicine, Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang, People’s Republic of China; 4Preventive Medicine Center, The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, Heilongjiang, People’s Republic of China

Correspondence: Xiaoning Li, Department of Acupuncture, The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, 411 Gogol Street, Nangang District, Harbin, Heilongjiang, People’s Republic of China, Tel +86 13313699268, Email lixiaoning28995@163.com

Objective: To investigate the correlation between serum levels of G protein-coupled receptor 4 (GPR4) and Biglycan (BGN) with the severity of Intervertebral Disc Degeneration (IVDD).
Methods: A total of 162 patients with IVDD treated at our hospital from August 2023 to August 2024 were included. The general information of patients was retrospectively collected. MRI was used to assess IVDD severity using the Pfirrmann grading system. Serum GPR4 and BGN levels were measured by enzyme-linked immunosorbent assay (ELISA). Multiple linear regression analysis was performed to identify risk factors for IVDD severity. Spearman’s and Pearson’s correlation analyses were used to evaluate the relationships between serum GPR4, BGN, and IVDD severity. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic value of serum GPR4 and BGN in IVDD.
Results: Significant differences in age and the proportion of diabetic patients as well as serum GPR4 and BGN were found among different Pfirrmann grades (P< 0.05). Serum GPR4 levels increased but BGN levels decreased with higher Pfirrmann grades (P< 0.05). Multiple linear regression analysis showed that age and serum GPR4 and BGN levels were risk factors for IVDD severity (P< 0.05). The results of the correlation analysis showed that serum GPR4 and age were positively correlated with the severity of IVDD (r=0.651, r=0.488, P< 0.001), while BGN was negatively correlated with the severity of IVDD (r=− 0.591, P< 0.001). The results of Spearman correlation analysis showed a negative correlation between serum GPR4 and BGN (P< 0.05). ROC curve analysis revealed that the AUC values for the diagnosis of IVDD using serum GPR4 alone, BGN alone, and the combination of GPR4 and BGN were 0.918, 0.811, and 0.919, respectively (P< 0.05). Moreover, the combination of GPR4 and BGN demonstrated higher sensitivity and specificity compared to either marker alone.
Conclusions: Serum GPR4 and BGN levels are identified as effective diagnostic indicators for IVDD, with serum GPR4 positively correlated but BGN negatively correlated with the severity of IVDD.

Keywords: G protein-coupled receptor 4, biglycan, intervertebral disc degeneration, correlation