Serum levels of the carboxy-terminal cross-linked telopeptide of type I collagen and laminin are elevated in Graves' disease but not in toxic nodular goiter.

We determined serum levels of laminin, carboxy-terminal cross-linked telopeptide, and carboxy-terminal propeptide of type I collagen (ICTP and PICP) in 27 patients with Graves' disease (GD) and in 31 patients with toxic nodular goiter (TNG). Elevated levels of soluble laminin and ICTP were observed in patients with GD prior to treatment (mean +/- SD concentration 1444 +/- 404 and 8.6 +/- 3.5 ng/ml, respectively), compared to patients with TNG (476 +/- 103 and 4.2 +/- 1.5 ng/ml) and normal controls (492 +/- 112 and 3.1 +/- 1.3 ng/ml, n = 34). In contrast, serum PICP concentrations were not different between patients with GD or TNG and normal controls. In GD patients serum ICTP and laminin levels decreased during thiamazole treatment and normalized within 4 and 8 weeks of therapy. There was no correlation between serum ICTP and laminin levels and serum levels of thyroid hormones and/or autoantibodies, respectively. Serum ICTP and laminin could be markers for alterations of extracellular matrix during GD and release of matrix components in the circulation and/or reflect an impaired clearance.