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 p arathyroidectomy (PTX) for primary hyperparathyroidism (PHPT) is not clear. It is uncertain whether circulating interleukin-6 (IL-6) plays a role in m ediating the acute withdrawal of the effects of parathyroid hormone (PTH) o n bone turnover after PTX. The aims of this study were to determine the tim e course of immediate changes in biochemical markers of bone turnover after PTX and whether circulating IL-6 is involved in the immediate changes of b one turnover after PTX. Design and Methods: IL-6 and bone turnover markers were measured in eight w omen (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 thos e from eight individually matched women (healthy controls) and five subject s undergoing major surgery (surgical controls). Results: At baseline, serum levels of IL-6 and bone turnover markers were h igher in PHPT than those in healthy controls (P<0.05). Serum levels of proc ollagen 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 si gnificantly by 21-41% within 24h (P<0.05). Serum IL-6 levels increased imme diately in both PHPT and surgical controls at postoperative follow-up (repe ated measures ANOVA). Conclusions: (1)PTX decreases bone resorption immediately and (2) circulati ng IL-6 is not involved in the changes in bone turnover immediately after P TX.