Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias street, 11527, Athens, Greece.
Department of Endocrinology, 'Evangelismos' General Hospital of Athens, 45-47 Ypsilantou street, 10676, Athens, Greece.
Endocrine. 2018 Jul;61(1):83-93. doi: 10.1007/s12020-018-1550-3. Epub 2018 Feb 17.
Irisin, a newly discovered adipo-myokine, is implicated in the modulation of the adipose phenotype, increasing energy expenditure and ameliorating systemic metabolism. Our aim was to investigate circulating irisin in subclinical hypothyroidism (SH) and study its associations with cardiometabolic risk factors.
In a large case-control study, serum irisin, insulin resistance and lipid parameters, classic adipokines, inflammatory and hepatic biomarkers, and cardiovascular risk factors were determined in 120 consecutive patients with SH and 120 healthy controls matched on age, gender, and date of blood draw. Sixteen patients with SH received L-T4 treatment and, after 6 months, serum irisin and other biomarkers were assessed.
SH cases exhibited significantly higher circulating irisin than controls (p < 0.001). In all participants, irisin was positively associated with TSH, anti-TG, HOMA-IR, C-peptide, lipid and inflammatory biomarkers, leptin, and cardiovascular risk factors, including Framigham score and apolipoprotein B/apolipoprotein A-I. Irisin was negatively correlated with adiponectin, HDL-C, and thyroid hormones. Serum irisin was independently associated with SH, above and beyond body mass index and cardiometabolic factors (p = 0.02). TSH was an independent predictor of circulating irisin (p = 0.003). L-T4 therapy did not reverse considerably the hyperirisinemic status in treated SH patients (p = 0.09).
Irisin may represent an adipo-myokine counterbalancing a potential, gradual deterioration of lipid metabolism and insulin sensitivity in SH as well as reflecting a protective compensatory mechanism against oxidative muscle and thyroid cell stress. More mechanistic and prospective studies shedding light on the pathogenetic role of irisin in SH are needed to confirm and extend these data.
鸢尾素是一种新发现的脂肪-肌因子，它参与调节脂肪表型，增加能量消耗，改善全身代谢。我们的目的是研究亚临床甲状腺功能减退症（SH）患者循环鸢尾素的变化，并研究其与心血管代谢危险因素的关系。
在一项大型病例对照研究中，我们检测了 120 例连续的 SH 患者和 120 名年龄、性别和采血日期匹配的健康对照者的血清鸢尾素、胰岛素抵抗和血脂参数、经典脂肪因子、炎症和肝生物标志物以及心血管危险因素。16 例 SH 患者接受了 L-T4 治疗，治疗 6 个月后，评估了血清鸢尾素和其他生物标志物。
SH 组患者的循环鸢尾素显著高于对照组（p<0.001）。在所有参与者中，鸢尾素与 TSH、抗甲状腺球蛋白抗体、HOMA-IR、C 肽、脂质和炎症生物标志物、瘦素以及包括 Framigham 评分和载脂蛋白 B/载脂蛋白 A-I 在内的心血管危险因素呈正相关。鸢尾素与脂联素、HDL-C 和甲状腺激素呈负相关。血清鸢尾素与 SH 独立相关，不受体重指数和心血管代谢因素的影响（p=0.02）。TSH 是循环鸢尾素的独立预测因子（p=0.003）。L-T4 治疗并不能显著改变治疗后的 SH 患者的高鸢尾素血症状态（p=0.09）。
鸢尾素可能是一种脂肪-肌因子，它可以平衡 SH 患者潜在的、逐渐恶化的脂质代谢和胰岛素敏感性，反映了一种针对氧化应激的肌肉和甲状腺细胞的保护代偿机制。需要更多的机制和前瞻性研究来阐明鸢尾素在 SH 中的发病机制作用，以证实和扩展这些数据。
