科學家在實驗室使用人的成體干細胞培育出部分顎骨,。他們指出，這是第一次通過這種方法制成復雜的大小適合于解剖的骨骼,，他們希望這種技術不僅能治療這種特殊關節(jié)的疾病,，還能矯正其他骨骼的問題。
哥倫比亞大學的這個研究結(jié)果公布在《美國科學院院刊》上,。實驗室合成的骨骼是顳下頜關節(jié),。這一關節(jié)的問題可能由出生缺陷、關節(jié)炎或者損傷造成,。雖然該關節(jié)的問題很常見，但它很難治療,。該關節(jié)有著復雜的結(jié)構,，這使得它很難通過移植身體其他部位的骨骼進行修復。
在這項新研究中,，科學家用到了人骨髓中的干細胞,。他們把這些干細胞植入一個組織架中，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計的生物反應器培育細胞,，這種反應器能讓成長的組織浸泡在自然骨骼生長所需要的含量精確的營養(yǎng)成分中。
該研究第一研究人員戈達納·伍加克·諾瓦科維克說：“使用患者自身干細胞的骨骼移植的可行性將會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潛在地改變醫(yī)生執(zhí)行整形手術的能力,，如嚴重受損后或癌癥治療。她說：“我們認為下顎骨是對我們技術的最嚴峻的考驗,，只要這一問題得到解決,，你就可以制作任何形狀。”她強調(diào)在實驗室里合成的關節(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,。
科學家面臨的一大挑戰(zhàn)是找到有血液供應的骨骼的合成方法，這樣就容易與宿主的血液供應連接,。去年幫助合成人工氣管的布里斯托爾大學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：“科學家在該領域面對的重要問題之一是如何合成有著合適維度的一塊骨骼,，對一些骨骼缺陷來說這很重要?，F(xiàn)在，科學家已經(jīng)合成形狀高度精確的骨骼,，這是組織工程學中令人欣慰的一面,。”（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.
