Immediate changes in biochemical markers of bone turnover and circulating interleukin-6 after parathyroidectomy for primary hyperparathyroidism

Objective: The time course of the immediate change in bone turnover after parathyroidectomy (PTX) for primary hyperparathyroidism (PHPT) is not clear. It is uncertain whether circulating interleukin-6 (IL-6) plays a role in mediating the acute withdrawal of the effects of parathyroid hormone (PTH) on bone turnover after PTX. The aims of this study were to determine the time course of immediate changes in biochemical markers of bone turnover after PTX and whether circulating IL-6 is involved in the immediate changes of bone turnover after PTX. Design and Methods: IL-6 and bone turnover markers were measured in eight women (aged 55 +/- 11 years, mean +/- S.D.) with PHTP at baseline and at 1-2 h, and 1, 2, 5, 7 and 12 days after PTX. We compared the results with those from eight individually matched women (healthy controls) and five subjects undergoing major surgery (surgical controls). Results: At baseline, serum levels of IL-6 and bone turnover markers were higher in PHPT than those in healthy controls (P<0.05). Serum levels of procollagen propeptides increased by 22 and 27% at days 2 and 5, respectively, compared with baseline (P<0.05). Serum tartrate-resistant acid phosphatase decreased by 2 days after PTX, and urinary collagen crosslinks decreased significantly by 21-41% within 24h (P<0.05). Serum IL-6 levels increased immediately in both PHPT and surgical controls at postoperative follow-up (repeated measures ANOVA). Conclusions: (1)PTX decreases bone resorption immediately and (2) circulating IL-6 is not involved in the changes in bone turnover immediately after PTX.