博士论文全文发表： Functional tissue engineering of human heart valve leaflets

henryjia

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Functional tissue engineering of human heart valve leaflets, 不错的一篇博士论文！拿来大家分享。
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9 v: @* E9 z% [4 fThe aortic heart valve, situated between the aorta and the left ventricle, is one of the% e8 S7 P7 \2 k, A/ c" f9 e0 `
four valves in the heart controlling the blood flow (chapter 1). It consists of three! ], s( i5 Q( N% P2 K. E/ Y
leaflets, with sufficient coaptation areas to ensure closure of the valve. The valve0 A% A  D3 C4 k5 @9 c3 v$ Z
opens and closes about 3.7 billion times in a lifetime, requiring strength, flexibility,
6 j$ Q+ f$ {$ c; B, fand durability of the tissue. For this imposing function, the leaflets have a highly
1 c" d& o1 w, I" @; V" Z3 u% borganized and specific tissue structure. When valve function is impaired, for example by calcification of the leaflets or inherited diseases, a live-threatening situation2 a$ k* n' ?5 N+ r4 d
occurs as insufficient oxygen is being supplied to the body. A common treatment
$ Q. U& U3 i/ _& k) X: wis the replacement of the aortic valve with either a mechanical valve or a bioprosthetic valve. The durability of a mechanical valve is excellent. However, patients
" A1 U4 ~4 V7 A& {+ B' }% Whaving such a valve implanted, require lifelong anticoagulation therapy to prevent
  \- l( Y5 X) _$ g) Cthrombo-embolism, the formation of blood clots on the surface of the valve leaflets.2 D9 Z, k- h6 X  {; R
This treatment itself results in increased risks of internal bleedings. Patients with a
# o$ @+ k( c+ v. h; r1 ^" Pbioprosthetic valve, for example a glutaraldehyde-treated porcine valve or a cryopreserved human donor valve, do not face anticoagulation therapy. The drawback of
( Y5 w  f8 q* qthis type of heart valve replacement is that they are less durable caused by enhanced  ^4 I. }+ y0 ~8 |
calcification and immune reactions of the body. All heart valve replacements share; x8 l, q6 M' O; }+ T
the major disadvantage that they are non-living structures and, therefore, not able to
  y/ O! `1 F9 {. @grow, repair and remodel in response to a changing environment, features which are
" w; d4 }# c  W% f6 \2 Dof particular importance in children.$ j9 j: }+ u+ {' {- H
The ideal heart valve replacement is autologous, engineered from material of the& W2 w2 m/ f* ]8 {: S
patient itself to prevent immune reactions, and living to be able to grow, repair and
; e( @- J- O9 _# J( S7 Gremodel. The emerging field of tissue engineering focuses on the engineering of such
- `! j+ Z) Z" u; E) M6 L! Korgans. The principle of tissue engineering is to seed and culture cells from the recipient onto a carrier material, the scaffold, which degrades while the tissue is developing" l6 n" l& M- i& v5 B9 H$ U" e
outside the body (in-vitro). As soon as the tissue properties are sufficient to withstand. a/ q. n; F  H5 E" G
in-vivo conditions, the tissue can be implanted into the recipient. Heart valve replacements can be engineered according to this principle (chapter 2). Ten years ago, the
) ]" u1 z2 w* m1 q) M' J' sfirst successful replacement of one of the pulmonary valve leaflets by a tissue engineered leaflet was reported in lambs. Nowadays, complete tissue engineered valves2 ~  f& b4 Z# _# L" x9 w
are shown to be fully functional in the pulmonary position in animal studies. The
2 y; U3 l1 g! _. A7 Ypulmonary valve is, however, exposed to lower pressures and flows than the aortic# G# }+ O) n8 o. x6 c
valve. A valve, able to resist the pressures and flows in the aortic position has not yet
' W0 W; J' \2 f1 w. k& kbeen created, using the principle of tissue engineering and a relatively fast degrading; h. |  e1 N; J9 U" v5 x
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botizhou

Thanks.

henryjia

求助版主：我似乎发错地方了，能否麻烦版主转到心脏干细胞专区。多谢！