TNF-α gene expression in relation to TNF-α level and bone mineral density in Polish patients with celiac disease

Background Osteopenia and osteoporosis are common complications of celiac disease (CD). Objectives Given the inflammatory background of bone disorders, this study aimed to assess the impact of TNF-α gene expression and its serum level on bone mineral density (BMD) in individuals with CD. Patients and methods The study at the start included 70 adults: 51 women and 9 men with CD, and 10 healthy controls: 8 women, 2 men. In the first phase of the study, densitometric measurements of the lumbar spine (L1–L4) and femoral neck (FN) were performed using dual-energy x-ray absorptiometry (DXA) to identify patients with celiac disease and decreased BMD. These patients constituted Group A (CD with osteopenia/osteoporosis, n = 12). Group B (CD with normal BMD, n = 6), and Group C (healthy controls with normal BMD, n = 6) were matched for sex, age and body mass to patients in group A. In the second phase of the study, TNF-α gene expression was quantified using the real-time quantitative PCR (qRT-PCR) method, and serum TNF-α levels were measured with an enzyme-linked immunosorbent assay (ELISA). In third phase, statistical analyses were conducted to investigate the correlations between TNF-α expression and serum TNF-α levels with bone and anthropometric parameters. Results No statistically significant differences in TNF-α gene expression or TNF-α serum levels were found between the groups. In Group A, TNF-α expression did not correlate with bone or anthropometric measures. However, in Group B, lower TNF-α expression correlated with higher BMI, FN BMD, L1–L4 BMD, and Z-scores. In contrast, healthy controls showed a positive correlation between TNF-α expression and BMD, T-score, and Z-score of the FN. There was also no statistically significant correlation between TNF-α cytokine concentration, and the parameters studied in groups A and B. Conclusions In this study, TNF- α , both in terms of gene expression and serum level, does not appear to correlate with BMD status in individuals with CD and osteopenia/osteoporosis. Larger longitudinal studies integrating additional cytokines and signaling pathways are needed to clarify the role of TNF-α in bone loss in celiac disease.