Lipocalin-2 as a marker of inflammation, bone density, and triglyceride-glucose index for new-onset arthritis patients in Mosul, Iraq

Lipocalin-2 is an acute phase-associated adipokine that can serve as an inflammatory and biomarker indicator of cartilage deterioration in osteoarthritis. However, its role in the musculoskeletal system remains not fully understood. Hence, this study aimed to evaluate lipocalin-2 and its relationship with markers of inflammation (Interferon-gamma, ESR, and CRP), bone density (vitamin D3 and calcium), and the triglyceride-glucose index in new-onset arthritis patients in Mosul, Iraq. This study included 125 participants aged 20 to 65, divided into two groups. The Arthritis Patient Group comprised 70 participants (37 females and 33 males) attending the Bone Diseases Consultation Unit at the Ibn Sina Teaching Hospital in Mosul, Iraq. The Control Group comprised 31 females and 24 males. Ethical approval was obtained from the Iraqi Ministry of Health - Nineveh Health (No. 2022095). Commercial ELISA kits were used to measure serum lipocalin-2, Interferon-gamma, ESR, and CRP as inflammation markers, vitamin D3, and calcium as bone density markers. Moreover, the Triglyceride Glucose (TYG) Index was evaluated. The findings revealed a significant increase in lipocalin-2 levels in males compared to females, with LCN-2 increasing with age. Arthritis patients showed a significant increase (72%) in lipocalin-2 levels. Inflammatory indicators (erythrocyte sedimentation rate, C-reactive protein, interferon-gamma) displayed significant increases (46%, 1200%, and 581%, respectively). Glucose (23%), triglycerides (71%), and TYG index (21%) also exhibited significant increases. Meanwhile, bone density indicators (vitamin D3 and calcium) found a significant decrease (53% and 20%, respectively) in arthritis patients. Linear correlation coefficient (R) analysis revealed a significant positive relationship between lipocalin-2 and indicators of inflammation, glucose, TG, and TYG index. This study's findings suggest that LCN-2 serum levels were higher in patients with new-onset arthritis than in controls in Mosul, and LCN-2 serum increased in males compared with females and getting older serum LCN-2 increased for the patients and control groups. Furthermore, a significant correlation was found between the Triglyceride Glucose Index, which measures metabolic disorders, and serum LCN-2 levels and inflammatory indicators in new-onset arthritis patients in Mosul, Iraq.