美國(guó)德州大學(xué)加爾威史東醫(yī)學(xué)分部（University of Texas Medical Branch,，簡(jiǎn)稱UTMB at Galveston）及Neurobiotex公司的研究人員發(fā)現(xiàn)，老年黃斑病變(Age-related Macular Degeneration,，簡(jiǎn)稱AMD)與眼部的鋅含量有很大的關(guān)聯(lián)性,。此研究發(fā)表于三月份的Experimental Eye Research期刊。UTMB的眼科醫(yī)師也是此研究的作者Erik van Kuijk表示：「這份研究除了對(duì)AMD疾病有更深入的了解外,，也有助于科學(xué)家針對(duì)AMD開發(fā)更有效的治療方法,。」
AMD是一種視網(wǎng)膜(retina)退化病變,，會(huì)導(dǎo)致中央視力逐漸受損,。在美國(guó)大約有數(shù)百萬(wàn)人罹患此疾，特別是年齡超過(guò)75歲的老人,，罹患率超過(guò)30%,。又可分為干型老年黃斑病變(Dry AMD)及濕型老年黃斑病變(Wet AMD)。Dry AMD約占所有病例的90%,，其黃斑點(diǎn)底部的視網(wǎng)膜色素上皮層細(xì)胞(retinal pigment epithelial cells, RPE) 聚積黃白色的沉積物,，叫做脈絡(luò)膜小疣(drusen)。這些沉積物是由感光細(xì)胞排出的廢物,，不知何故,，RPE細(xì)胞失去了排除drusen的能力，造成細(xì)胞逐步退化,。雖不會(huì)完全失去中央視覺(jué),，不過(guò)對(duì)于微細(xì)視力的作業(yè)，例如閱讀,、繪畫等帶來(lái)困難,。目前尚無(wú)有效醫(yī)學(xué)治療方法。而Wet AMD病例約占10%,，患者黃斑點(diǎn)后部會(huì)出現(xiàn)不正常的血管生長(zhǎng),，血管爆裂后血液流到黃斑點(diǎn)，使感光細(xì)胞受損,，會(huì)對(duì)中央視覺(jué)造成嚴(yán)重?fù)p害,。病患中女性多于男性，大多與家族遺傳或抽煙等生活習(xí)慣有關(guān),。
研究人員就是在脈絡(luò)膜小疣中發(fā)現(xiàn)高量的鋅,，對(duì)于這項(xiàng)發(fā)現(xiàn)Kuijk一點(diǎn)也不意外，因?yàn)殇\也負(fù)責(zé)阿茲海默癥病人腦部斑點(diǎn)的形成,，所以推測(cè)鋅可能也是造成AMD的因子,。Neurobiotex公司的Frederickson博士就表示：「AMD可視為眼部的阿茲海默癥。因?yàn)檫@兩種疾病都與折迭錯(cuò)誤的amyloid蛋白有關(guān),，且鋅或銅都會(huì)進(jìn)入斑點(diǎn)中,。」研究人員發(fā)現(xiàn)在斑點(diǎn)中大約含有5~10%的游離態(tài)或結(jié)合松散的鋅,，雖然鋅對(duì)于細(xì)胞的構(gòu)型很重要,，但濃度過(guò)高仍會(huì)造成許多問(wèn)題,。因此，研究人員使用能獒合鋅離子的試劑ZP-1以抓取過(guò)多的游離態(tài)鋅離子,，看看是否能減緩AMD的病情,。
UTMB黃斑退化癥研究中心的主任Michael Boulton表示：「Kuijk研究團(tuán)隊(duì)的發(fā)現(xiàn)對(duì)于AMD的了解具有卓越的貢獻(xiàn)，若能在早期就阻止或預(yù)防過(guò)量的游離鋅對(duì)眼疾造成的惡化,，將能保護(hù)視網(wǎng)膜細(xì)胞不受到損壞,，也將能改善美國(guó)超過(guò)七百萬(wàn)名AMD病人的生活質(zhì)量?！?/p>
(資料來(lái)源 : Bio.com)
英文原文：
3/24/2007 12:15:00 PM ET Related symbols: AMD
NetIndia123.com
Zinc may be behind age-related mascular degeneration
Washington | March 23, 2007 1:24:42 PM IST
US scientists have discovered zinc's involvement in age-related macular degeneration (AMD), the leading cause of blindness in the elderly in developed countries.
Researchers at the University of Texas Medical Branch at Galveston (UTMB) and the Galveston-based spinoff Neurobiotex, Inc. found high levels of zinc in deposits in the eye, which are an indication of AMD.
UTMB ophthalmologist Erik van Kuijk, senior author of the study, says that the new findings contributed to a better understanding of AMD and may facilitate the development of effective treatments.
The researchers said that an early sign and a presumed trigger of the eye disease is the formation of microscopic plaques, called 'drusen,' in the eye. Exactly what these plaque-like drusen do and why they form is not yet fully understood, they noted. We have discovered that the drusen in the eyes of those with AMD have very high levels of zinc,' said van Kuijk, associate professor in the UTMB Department of Ophthalmology and Visual Sciences.
Since zinc had previously been shown to contribute to the formation of brain plaques in patients with Alzheimer's disease, van Kuijk said that it was logical to test whether zinc might also contribute to the formation of the plaque-like drusen in the eye. He said that they do so using a reagent called ZP-1. 'What is particularly important is that within the zinc we found a small pool - about 5 to 10 percent - of what is known as 'free' or 'loosely bound' zinc,' van Kuijk explained. 'Generally, zinc is essential to keeping a molecule's shape, but mobilised zinc can cause lots of problems. However, since it is a small proportion of the overall zinc pool, it's straightforward to target it. That's what researchers are beginning to do with Alzheimer's disease by developing methodologies and drugs that can capture this mobilised zinc and see if doing that slows down the degenerative process. This study shows that we could now potentially take a similar route for AMD treatment,' he added. The researchers looked at eyes procured by the Montana Eye Bank from deceased patients with AMD that contained several large sub-RPE deposits and compared them to post-mortem eyes from a similar age group that had no known eye disease and no deposits in the macula. They analysed these using zinc-sensing molecules like ZP-1, which glow when they bind with zinc. 'The pioneering work by Dr. van Kuijk and his colleagues is an important development in our understanding of AMD. The possibility of targeting zinc to stop or reverse drusen growth is important because doing so has the potential to arrest the progression of AMD early, before irreversible damage to the retinal cells occurs' said Dr Michael Boulton, director of the new Macular Degeneration Center at UTMB.'A treatment for AMD is desperately needed as the disease affects up to 7 million Americans. This equates to 2,000 AMD sufferers here on Galveston Island,' Boulton added. The new findings have been published in the journal Experimental Eye Research. (ANI) Researchers at the University of Texas Medical Branch at Galveston (UTMB) and the Galveston-based spinoff Neurobiotex, Inc. found high levels of zinc in deposits in the eye, which are an indication of AMD. UTMB ophthalmologist Erik van Kuijk, senior author of the study, says that the new findings contributed to a better understanding of AMD and may facilitate the development of effective treatments. The researchers said that an early sign and a presumed trigger of the eye disease is the formation of microscopic plaques, called 'drusen,' in the eye. Exactly what these plaque-like drusen do and why they form is not yet fully understood, they noted. We have discovered that the drusen in the eyes of those with AMD have very high levels of zinc,' said van Kuijk, associate professor in the UTMB Department of Ophthalmology and Visual Sciences. Since zinc had previously been shown to contribute to the formation of brain plaques in patients with Alzheimer's disease, van Kuijk said that it was logical to test whether zinc might also contribute to the formation of the plaque-like drusen in the eye. He said that they do so using a reagent called ZP-1. 'What is particularly important is that within the zinc we found a small pool - about 5 to 10 percent - of what is known as 'free' or 'loosely bound' zinc,' van Kuijk explained. 'Generally, zinc is essential to keeping a molecule's shape, but mobilised zinc can cause lots of problems. However, since it is a small proportion of the overall zinc pool, it's straightforward to target it. That's what researchers are beginning to do with Alzheimer's disease by developing methodologies and drugs that can capture this mobilised zinc and see if doing that slows down the degenerative process. This study shows that we could now potentially take a similar route for AMD treatment,' he added. The researchers looked at eyes procured by the Montana Eye Bank from deceased patients with AMD that contained several large sub-RPE deposits and compared them to post-mortem eyes from a similar age group that had no known eye disease and no deposits in the macula. They analysed these using zinc-sensing molecules like ZP-1, which glow when they bind with zinc. 'The pioneering work by Dr. van Kuijk and his colleagues is an important development in our understanding of AMD. The possibility of targeting zinc to stop or reverse drusen growth is important because doing so has the potential to arrest the progression of AMD early, before irreversible damage to the retinal cells occurs' said Dr Michael Boulton, director of the new Macular Degeneration Center at UTMB. 'A treatment for AMD is desperately needed as the disease affects up to 7 million Americans. This equates to 2,000 AMD sufferers here on Galveston Island,' Boulton added. The new findings have been published in the journal Experimental Eye Research. (ANI)
