海藻膠+幹細胞3d列印 治療眼角膜受損 (失明)

3D-printed corneas could save millions' vision JULY 17, 2018 BY NANCY CROTTIBritish scientists have 3D printed the first human corneas, yielding a potential fix to the worldwide shortage of corneas for implantation. The Newcastle University researchers created a bio-ink using stem cells from a healthy donor cornea mixed with alginate and collagen. They used a simple, low-cost 3D bio-printer to extrude the bio-ink in concentric circles to form the shape of a human cornea. It took less than 10 minutes to print. The proof-of-concept research was published in May in Experimental Eye Research. "Many teams across the world have been chasing the ideal bio-ink to make this process feasible," said lead researcher Che Connon, a professor of tissue engineering in a prepared statement. "Our unique gel – a combination of alginate and collagen – keeps the stem cells alive whilst producing a material which is stiff enough to hold its shape but soft enough to be squeezed out the nozzle of a 3D printer. "The researchers previously kept cells alive for weeks at room temperature within a similar hydrogel. Their ready-to-use bio-ink containing stem cells, will allow users to start printing tissues without having to worry about growing the cells separately, Connon added. The scientists, including first author Abigail Isaacson from the university's Institute of Genetic Medicine, also demonstrated that they could build a cornea to match a patient's unique specifications. The dimensions of the printed tissue were originally taken from an actual cornea. By scanning a patient's eye, they could use the data to rapidly print a cornea which matched the size and shape.Several years of testing must occur before the 3D printed corneas may be used for transplant, according to Connon."However, what we have shown is that it is feasible to print corneas using coordinates taken from a patient eye and that this approach has potential to combat the worldwide shortage," he said. As the outermost layer of the human eye, the cornea has an important role in focusing vision. About 10 million people worldwide need surgery to prevent corneal blindness due to diseases such as trachoma, an infectious disease. Another nearly 5 million people suffer total blindness due to corneal scarring caused by burns, lacerations, abrasion or disease. Reducing the need for donor corneas would help some people living with vision loss to regain their sight, according to Neil Ebenezer, MD, director of research, policy and innovation at Fight for Sight, UK charity that funds research into the prevention and treatment of blindness and eye disease."This research highlights the significant progress that has been made in this area and this study is important in bringing us one step closer to reducing the need for donor corneas, which would positively impact some patients living with sight loss," Ebenezer said in the statement.

(成大 劉嚴文醫師) 幹細胞再生 獼猴心臟肌肉 登期刊Nature Biotechnology

幹細胞修復心臟受損功能 成大醫師研究登上國際期刊 2018-07-16 16:05聯合報 記者吳佩旻╱即時報導 成大醫學院內科部臨床醫學副教授劉嚴文醫師，日前參與美國西雅圖華盛頓大學Professor Murry「幹細胞與再生醫學研究中心」團隊，進行非人類靈長類動物（獼猴）心肌再生研究，移植由人類胚胎幹細胞分化衍生出的心肌細胞，成功地讓心肌梗塞的猴子再生新的心臟肌肉，修復受損嚴重的心臟並恢復功能，並登上國際旗艦期刊Nature Biotechnology （自然－生物科技）。心肌梗塞會導致心肌細胞壞死，使心臟肌肉缺乏再生能力，所以心肌梗塞最終會導致心臟衰竭，是現代人的主要死亡原因之一。因此如何使心肌細胞再生、恢復心臟功能，就成為「再生醫學」的重要研究課題。此研究成果刊登於國際期刊中，劉嚴文醫師名列第一作者，有望在未來數年內進入臨床試驗。心臟病高居全球十大死因之首，現代醫療技術雖然可大幅降低心肌梗塞與心臟衰竭的死亡率，但只能預防或減少心肌梗塞的後遺症，或預防急性心血管疾病再發生，卻無法促進心臟肌肉細胞再生，心肌梗塞後的心臟衰竭，仍是造成心臟病患死亡的主要原因之一。為此，華盛頓大學「幹細胞與再生醫學研究中心」團隊從2012年開始進行非人類靈長類動物心肌再生的研究針對「多能性幹細胞」進行研究，多年前證實利用體外培養的方式，能有效大量分化成心肌細胞。劉嚴文獲得成大醫院「菁英計畫」贊助，在臨床醫學所指導教授謝清河教授推薦下，於2013年加入進行博士後研究。劉嚴文說，在這一系列研究中，先利用心導管技術讓猴子的心臟產生心肌梗塞及嚴重心臟衰竭，經由心臟核磁共振檢查後發現，左心室射出分率（即心臟功能）由6成5降低到4成，之後再移植「多能性幹細胞」衍生的心肌細胞，經過4個星期，猴子心臟再生出數量可觀的心臟肌肉，修補了約3分之1的心肌梗塞範圍。如此一來，能大幅減少心肌梗塞的影響，心臟功能也從4成增至5成，在幹細胞移植後的3個月，心臟功能仍持續進步中。該團隊成為全世界第一個成功大量移植「人類胚胎幹細胞」衍生的心肌細胞，讓心肌梗塞的猴子心臟再生出新的心臟肌肉，這些研究在2014年曾發表於Nature（自然）雜誌，劉嚴文醫師名列共同作者。不過之後團隊發現，雖然幹細胞治療可以讓心臟長出新的肌肉，但卻無法改善心臟功能，而且還會產生「致命性心律不整」。為改善情況，劉嚴文被指定主導後續計畫，擁有臨床經驗的他，很快就看見實驗室研究人員的盲點與不足，在重新設計研究流程，包括擴大心肌梗塞面積、加重心臟衰竭程度後，移植「多能性幹細胞」衍生的心肌細胞，不再增加致命性心律不整的危險。劉嚴文說，Professor Murry曾邀他留在美國參與後續研究，開出的條件很誘人，但他掙扎考慮了半年，還是決定回台灣。他說，「我在成大完成醫學系以及臨床醫學博士學位，內科住院醫師以及心臟內科專科醫師訓練也在成大醫院完成。因為成大，才會有現在的我；假如我有任何的能力與成就，也都是成大所給我的，這是我與成大之間的機緣。」。劉嚴文說，他對成大有特別的感情與使命感，希望能將自己在國外所學帶回學校。此外，當醫師也是他最大的志業，加上捨不得家人，種種因素讓他最後決定回台灣。