Osteopontin levels in plasma, muscles, and bone in patient with non-healing diabetic foot ulcers: A new player in wound healing process?

Background: The present study was designed to investigate the impact of osteopontin (OPN) in different tissue (e.g., plasma, muscles and bone) on amputation rate (in-hospital and during one year follow-up) for non-healing diabetic foot ulcers (DFUs). Methods: This pilot study consisted of 30 diabetic patients, hospitalized due to non-healing DFUs. Patients were divided into two groups: Group 1 included 14 patients who underwent limb-preserved debridement procedure without amputation; Group 2 included 16 subjects who underwent amputation. Additionally, recurrent amputation rate during 1 year follow-up was investigated. Results: Plasma OPN was higher and bone OPN was lower in Group 2 compared to Group 1 (p = 0.016 and p = 0.004, respectively). In the logistic regression analysis, bone OPN emerged as a significant independent predictor of amputation (OR = 0.042, 95% CI 0.003–0.699, p = 0.027). Plasma OPN was also associated with amputation such that each unit increase in plasma OPN was associated with an increase in odds of amputation of 17.7% (95% CI 0.997–1.388, p = 0.045). During 1 year follow-up 11 patients underwent recurrent amputation. Plasma OPN were higher and bone osteopontin was lower in patients who underwent amputation compared to patients who did not need amputation at one year follow-up. However, in GLM analysis bone OPN was only marginally associated with one year amputation (OR 0.001, 95% CI 0.000–2.0, p = 0.076). Conclusions: Decreased levels of OPN in bone and increased plasma OPN are independently associated with in-hospital amputation. Consequently, plasma OPN may be relevant in the routine assessment of amputation risk in this patient population.