科學(xué)家在實(shí)驗(yàn)室使用人的成體干細(xì)胞培育出部分顎骨,。他們指出，這是第一次通過(guò)這種方法制成復(fù)雜的大小適合于解剖的骨骼,，他們希望這種技術(shù)不僅能治療這種特殊關(guān)節(jié)的疾病,，還能矯正其他骨骼的問(wèn)題。
哥倫比亞大學(xué)的這個(gè)研究結(jié)果公布在《美國(guó)科學(xué)院院刊》上,。實(shí)驗(yàn)室合成的骨骼是顳下頜關(guān)節(jié),。這一關(guān)節(jié)的問(wèn)題可能由出生缺陷、關(guān)節(jié)炎或者損傷造成,。雖然該關(guān)節(jié)的問(wèn)題很常見(jiàn),，但它很難治療。該關(guān)節(jié)有著復(fù)雜的結(jié)構(gòu),，這使得它很難通過(guò)移植身體其他部位的骨骼進(jìn)行修復(fù),。
在這項(xiàng)新研究中,，科學(xué)家用到了人骨髓中的干細(xì)胞。他們把這些干細(xì)胞植入一個(gè)組織架中,，借助患者的數(shù)碼成像形成精確的人下巴骨形狀,。然后他們使用特殊設(shè)計(jì)的生物反應(yīng)器培育細(xì)胞，這種反應(yīng)器能讓成長(zhǎng)的組織浸泡在自然骨骼生長(zhǎng)所需要的含量精確的營(yíng)養(yǎng)成分中,。
該研究第一研究人員戈達(dá)納·伍加克·諾瓦科維克說(shuō)：“使用患者自身干細(xì)胞的骨骼移植的可行性將會(huì)革新我們目前治療這種缺陷的方法,。”伍加克·諾瓦科維克稱，這種新技術(shù)還可能用于頭部和頸部的其他骨骼,，包括很難移植的頭骨和顴骨,。
用這種方法制造大小適合于解剖的人骨可能會(huì)潛在地改變醫(yī)生執(zhí)行整形手術(shù)的能力，如嚴(yán)重受損后或癌癥治療,。她說(shuō)：“我們認(rèn)為下顎骨是對(duì)我們技術(shù)的最嚴(yán)峻的考驗(yàn),，只要這一問(wèn)題得到解決，你就可以制作任何形狀,。”她強(qiáng)調(diào)在實(shí)驗(yàn)室里合成的關(guān)節(jié)只是骨骼,，不包括其他組織，如軟骨,。但是,，哥倫比亞研究組正在研究一種包括骨骼和軟骨的混雜移植的新方法。
科學(xué)家面臨的一大挑戰(zhàn)是找到有血液供應(yīng)的骨骼的合成方法,，這樣就容易與宿主的血液供應(yīng)連接,。去年幫助合成人工氣管的布里斯托爾大學(xué)的組織工程專家安東尼·霍倫德教授稱，在新骨骼用于患者前還需要做大量工作,。但是,，他說(shuō)：“科學(xué)家在該領(lǐng)域面對(duì)的重要問(wèn)題之一是如何合成有著合適維度的一塊骨骼，對(duì)一些骨骼缺陷來(lái)說(shuō)這很重要?，F(xiàn)在，科學(xué)家已經(jīng)合成形狀高度精確的骨骼,，這是組織工程學(xué)中令人欣慰的一面,。”（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS October 9, 2009, doi: 10.1073/pnas.0905439106
Engineering anatomically shaped human bone grafts
Warren L. Graysona, Mirjam Fr?hlicha,b, Keith Yeagera, Sarindr Bhumiratanaa, M. Ete Chanc, Christopher Cannizzarod, Leo Q. Wana, X. Sherry Liuc, X. Edward Guoc and Gordana Vunjak-Novakovica,1
aLaboratory for Stem Cells and Tissue Engineering, Department of Biomedical Engineering, Columbia University, 622 West 168th Street, VC 12-234, New York, NY 10032;
bEducell Ltd., Letaliska 33, 1000 Ljubljana, Slovenia;
cBone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, 1210 Amsterdam Avenue, MC 8904, New York, NY 10027; and
dDepartment of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA 02155
The ability to engineer anatomically correct pieces of viable and functional human bone would have tremendous potential for bone reconstructions after congenital defects, cancer resections, and trauma. We report that clinically sized, anatomically shaped, viable human bone grafts can be engineered by using human mesenchymal stem cells (hMSCs) and a “biomimetic” scaffold-bioreactor system. We selected the temporomandibular joint (TMJ) condylar bone as our tissue model, because of its clinical importance and the challenges associated with its complex shape. Anatomically shaped scaffolds were generated from fully decellularized trabecular bone by using digitized clinical images, seeded with hMSCs, and cultured with interstitial flow of culture medium. A bioreactor with a chamber in the exact shape of a human TMJ was designed for controllable perfusion throughout the engineered construct. By 5 weeks of cultivation, tissue growth was evidenced by the formation of confluent layers of lamellar bone (by scanning electron microscopy), markedly increased volume of mineralized matrix (by quantitative microcomputer tomography), and the formation of osteoids (histologically). Within bone grafts of this size and complexity cells were fully viable at a physiologic density, likely an important factor of graft function. Moreover, the density and architecture of bone matrix correlated with the intensity and pattern of the interstitial flow, as determined in experimental and modeling studies. This approach has potential to overcome a critical hurdle—in vitro cultivation of viable bone grafts of complex geometries—to provide patient-specific bone grafts for craniofacial and orthopedic reconstructions.
