Inhibition of TNF-αReverses the Pathological Resorption Pit Profile of Osteoclasts from Patients with Acute Charcot Osteoarthropathy
We hypothesised that tumour necrosis factor-α(TNF-α) may enhance receptor activator of nuclear factor-κβligand- (RANKL-) mediated osteoclastogenesis in acute Charcot osteoarthropathy. Peripheral blood monocytes were isolated from 10 acute Charcot patients, 8 diabetic patients, and 9 healthy control subjects and culturedin vitroon plastic and bone discs. Osteoclast formation and resorption were assessed after treatment with (1) macrophage-colony stimulating factor (M-CSF) and RANKL and (2) M-CSF, RANKL, and neutralising antibody to TNF-α(anti-TNF-α). Resorption was measured on the surface of bone discs by image analysis and under the surface using surface profilometry. Although osteoclast formation was similar in M-CSF + RANKL-treated cultures between the groups (p>0.05), there was a significant increase in the area of resorption on the surface (p<0.01) and under the surface (p<0.01) in Charcot patients compared with diabetic patients and control subjects. The addition of anti-TNF-αresulted in a significant reduction in the area of resorption on the surface (p<0.05) and under the surface (p<0.05) only in Charcot patients as well as a normalisation of the aberrant erosion profile. We conclude that TNF-αmodulates RANKL-mediated osteoclastic resorptionin vitroin patients with acute Charcot osteoarthropathy.