甲状腺激素抑制——挽救视力的一种新方法

福娃晶晶

2014年2月27日——新的研究表明,抑制甲状腺激素(TH)视网膜的活动可以保护视力的人受到广泛的视网膜退行性条件,包括色素性视网膜炎,利伯氏先天性黑内障(LCA),全色盲和年龄相关性黄斑变性。假说是基于鼠标研究的结果发表在美国国家科学院院刊》上.

该研究的调查小组包括来自俄克拉荷马大学的研究人员,犹他大学和美国国家眼科研究所。俄克拉何马州的研究人员正在开发一种潜在的治疗人类视网膜一种退化和提出专利申请他们的治疗方法。

“这些早期甲状腺激素的研究结果绝对是令人鼓舞的,”斯蒂芬·罗斯说,博士,研究总监基金会战斗失明。“然而,没有一个人——有或没有一个视网膜疾病——应该改变他们的甲状腺激素治疗没有咨询医生。甲状腺激素对人体有广泛的影响,因此改变治疗可能是重要的,和潜在的危险,影响。”

在视网膜变性的小鼠模型,包括那些对LCA和全色盲,科学家们表明,抑制锥生存信号有很强的影响。在某些情况下,某些地区的治疗视网膜有六倍比相应地区治疗视网膜视锥细胞。相反,增加活动超出正常水平加速锥变性。

视锥细胞最重要的一个人的独立性和灵活性,因为它们提供中央和白天的远见和能力感知细节和颜色。

“我们的作品灵感来自于先前的调查结果,高于正常值TH信号引起程序性死亡的各种人类细胞系和视锥细胞在老鼠的视网膜,”说Xi-Qin丁博士,这项研究的首席研究员,俄克拉荷马大学的。“我们推测,如果高信号死亡原因锥,抑制可能是保护锥。我们感到惊讶和兴奋,多么强大的保护作用在我们的模型”。

这是由甲状腺,影响体内每一个细胞和器官。他们还控制心率、肌肉力量、细胞替代和身体温度和重量。然而,由于它的广泛影响,TH治疗视网膜需要本地管理——也许滴眼剂。

“我们的研究,到目前为止,系统性,但是我们的下一步是确定当地抑制的有效性的锥形保护信号,”丁博士说。“我们还将研究是否抑制信号对棒有保护作用,正如我们所观察到高信号也消极地影响杆可行性。”

“甲状腺激素抑制的横切潜力是令人兴奋,”罗斯博士说。“它有可能帮助人们不管他们的遗传性视网膜疾病或潜在的遗传缺陷导致。此外,如果这种方法可以用来保存甚至小锥,它可以帮助人们保持他们的生活质量和独立。”

福娃晶晶

摘自美国抗盲基金会网站

Thyroid Hormone Suppression — An Emerging Approach for Saving Vision
Feb. 27, 2014 – New research suggests that suppressing thyroid hormone (TH) activity in the retina may preserve vision in people affected by a wide range of retinal degenerative conditions, including retinitis pigmentosa, Leber congenital amaurosis (LCA), achromatopsia and age-related macular degeneration. The hypothesis is based on results of mouse studies published in the Proceedings of the National Academy of Sciences.

The study’s investigative team included researchers from the University of Oklahoma, the University of Utah and the National Eye Institute. The Oklahoma researchers are now developing a potential therapy for humans with retinal degenerations and have filed a patent application for their treatment approach.

“These early thyroid hormone study results are definitely encouraging,” says Stephen Rose, Ph.D., chief research officer, Foundation Fighting Blindness. “However, no one — with or without a retinal disease — should change their thyroid hormone therapy without consulting a doctor. Thyroid hormones have wide-ranging effects on the body, so altering treatment is likely to have significant, and potentially dangerous, effects.”

In mouse models of retinal degeneration, including those for LCA and achromatopsia, the scientists showed that suppressing TH signaling had a strong effect on cone survival. In some cases, certain areas of the treated retinas had six times more cones than corresponding regions in untreated retinas. Conversely, increasing TH activity beyond normal levels accelerated cone degeneration.

Cones are most critical to a person’s independence and mobility, as they provide central and daytime vision and the ability to perceive details and colors.

“Our work was inspired by previous findings that higher-than-normal TH signaling induces programmed death of a variety of human cell lines and cones in the mouse retina,” says Xi-Qin Ding, Ph.D., the study’s lead investigator, of the University of Oklahoma. “We hypothesized that if high TH signaling causes cone death, suppressing it might be protective to cones. We were surprised and excited by how powerful the protective effect was in our models.”  

THs are produced by the thyroid gland and affect every cell and organ in the body. They also control heart rate, muscle strength, cell replacement and body temperature and weight. However, because of its wide-ranging effects, a TH therapy for the retina needs to be locally administered — perhaps as an eye drop.

“Our studies, thus far, have been systemic, but our next step is to determine the effectiveness of local suppression of TH signaling in cone preservation,” says Dr. Ding. “We will also examine whether suppressing TH signaling has any protective effects on rods, as we have observed that high TH signaling also negatively affects rod viability.”

“The cross-cutting potential of thyroid hormone suppression is exciting,” says Dr. Rose. “It has the potential to help people regardless of their inherited retinal disease or the underlying genetic defect causing it. Furthermore, if the approach can be used to preserve even a small population of cones, it can go a long way in helping people maintain their quality of life and independence.”