Department of Internal Medicine, University of Pisa, Italy.
Acta Diabetol. 2013 Feb;50(1):73-80. doi: 10.1007/s00592-012-0399-9. Epub 2012 May 26.
The relationship between inflammation, Hashimoto's thyroiditis (HT) and insulin resistance is still controversial. In this regard, a pretty complete evaluation of adipocytokines levels in patients with HT has not been performed so far. We assessed retinol binding protein-4 (RBP4), adipocyte-fatty acid binding protein (A-FABP), neutrophil gelatinase-associated lipocalin (NGAL) and tumor necrosis factor-α (TNFα) levels in 93 euthyroid HT patients and 51 healthy controls (CTL), also evaluating the possible correlation between adipocytokines levels and markers of insulin resistance. No significant differences between HT patients and CTL in fasting plasma glucose and insulin levels, and HOMA index were observed. HT patients had significantly higher RBP4, NGAL and A-FABP levels than CTL, while TNFα levels did not differ between the two groups. In HT patients, RBP4 was significantly related with fT3 and fT4 levels, while A-FABP with fT4 only. Moreover, in HT patients, either RBP4 or A-FABP was directly associated with plasma insulin and HOMA index. Circulating levels of these adipocytokines were not influenced by the presence of antithyroid peroxidase or antithyroglobulin autoantibodies or only one of them, neither by autoantibodies titer. In conclusion, euthyroid HT patients are characterized by a peculiar inflammatory response of the adipose tissue, apparently related to an early reduction in insulin sensitivity and to serum thyroid hormone levels, although within the normal range. These results suggest that HT patients with high RBP4 and A-FABP levels might deserve a particular attention, being potentially more exposed to develop insulin resistance and increased cardiovascular risk.
炎症、桥本甲状腺炎（HT）和胰岛素抵抗之间的关系仍存在争议。在这方面，目前尚未对 HT 患者的脂联素水平进行全面评估。我们评估了 93 例甲状腺功能正常的 HT 患者和 51 例健康对照者（CTL）的视黄醇结合蛋白 4（RBP4）、脂肪细胞脂肪酸结合蛋白（A-FABP）、中性粒细胞明胶酶相关脂质运载蛋白（NGAL）和肿瘤坏死因子-α（TNFα）水平，还评估了脂联素水平与胰岛素抵抗标志物之间的可能相关性。HT 患者的空腹血糖和胰岛素水平以及 HOMA 指数与 CTL 相比无显著差异。HT 患者的 RBP4、NGAL 和 A-FABP 水平明显高于 CTL，而两组之间的 TNFα 水平无差异。在 HT 患者中，RBP4 与 fT3 和 fT4 水平显著相关，而 A-FABP 仅与 fT4 相关。此外，在 HT 患者中，RBP4 或 A-FABP 与血浆胰岛素和 HOMA 指数直接相关。这些脂联素的循环水平不受抗甲状腺过氧化物酶或抗甲状腺球蛋白自身抗体或仅其中一种的存在或自身抗体滴度的影响。总之，甲状腺功能正常的 HT 患者表现出独特的脂肪组织炎症反应，这种反应显然与胰岛素敏感性的早期降低和血清甲状腺激素水平有关，尽管这些水平仍在正常范围内。这些结果表明，RBP4 和 A-FABP 水平较高的 HT 患者可能需要特别关注，因为他们可能更容易发生胰岛素抵抗和增加心血管风险。
