Levothyroxine (LT4) is effective for most patients with hypothyroidism. However, a minority of the patients remain symptomatic despite the normalization of serum thyrotropin levels. Randomized clinical trials including all types of patients with hypothyroidism revealed that combination levothyroxine and liothyronine (LT4+LT3) therapy is safe and is the preferred choice of patients versus LT4 alone. Many patients who do not fully benefit from LT4 experience improved quality of life and cognition after switching to LT4+LT3. For these patients, new slow-release LT3 formulations that provide stable serum T3 levels are being tested. In addition, progress in regenerative technology has led to the development of human thyroid organoids that restore euthyroidism after being transplanted into hypothyroid mice. Finally, there is a new understanding that, under certain conditions, T3 signaling may be compromised in a tissue-specific fashion while systemic thyroid function is preserved. This is seen, for example, in patients with metabolic (dysfunction)-associated fatty liver disease, for whom liver-selective T3-like molecules have been utilized successfully in clinical trials.

中文翻译：

---

甲状腺功能减退症的新兴疗法

左旋甲状腺素（LT4）对大多数甲状腺功能减退症患者有效。然而，尽管血清促甲状腺素水平正常化，少数患者仍然有症状。包括所有类型甲状腺功能减退症患者的随机临床试验表明，左旋甲状腺素和碘塞罗宁 (LT4+LT3) 联合治疗是安全的，并且是患者相对于单独 LT4 的首选治疗。许多未从 LT4 中完全受益的患者在改用 LT4+LT3 后，生活质量和认知能力得到改善。对于这些患者，正在测试可提供稳定血清 T3 水平的新型缓释 LT3 制剂。此外，再生技术的进步导致人类甲状腺类器官的开发，在移植到甲状腺功能减退小鼠体内后可恢复甲状腺功能正常。最后，有一个新的认识，即在某些条件下，T3 信号传导可能会以组织特异性方式受到损害，而全身甲状腺功能却得以保留。例如，在患有代谢（功能障碍）相关脂肪肝病的患者中就可以看到这种情况，肝脏选择性 T3 样分子已在临床试验中成功利用。