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

henryjia

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& v- ~3 j1 I& r; ~  ^2 UFunctional 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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The aortic heart valve, situated between the aorta and the left ventricle, is one of the. L. |9 ]8 c) d* z" W) M; v
four valves in the heart controlling the blood flow (chapter 1). It consists of three
! V. Q5 s# Z; }* w6 ?* B' J% vleaflets, with sufficient coaptation areas to ensure closure of the valve. The valve3 \: H& R- @2 v3 R8 r
opens and closes about 3.7 billion times in a lifetime, requiring strength, flexibility,
2 U+ Q4 n3 ^5 ^! N, Z; Q* _and durability of the tissue. For this imposing function, the leaflets have a highly
8 ^2 l' E. |: ?! @5 t* eorganized and specific tissue structure. When valve function is impaired, for example by calcification of the leaflets or inherited diseases, a live-threatening situation
8 O7 W. v( g2 Moccurs as insufficient oxygen is being supplied to the body. A common treatment
" k+ U+ r3 _5 {. t/ R5 ?) Lis 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
4 x3 t$ w* [" r' [6 c4 hhaving such a valve implanted, require lifelong anticoagulation therapy to prevent
/ \3 z- b8 m+ x- E7 Lthrombo-embolism, the formation of blood clots on the surface of the valve leaflets.; D6 `# t" m1 ^, b4 ^+ W
This treatment itself results in increased risks of internal bleedings. Patients with a% f+ M) L' a- t! }1 B! \! {, ]
bioprosthetic valve, for example a glutaraldehyde-treated porcine valve or a cryopreserved human donor valve, do not face anticoagulation therapy. The drawback of
+ D# K1 J4 m0 u( i; q6 N$ X' |! Sthis type of heart valve replacement is that they are less durable caused by enhanced
! |7 C* W" E. u, G( Bcalcification and immune reactions of the body. All heart valve replacements share! l7 O+ g: t7 r; `4 u1 c
the major disadvantage that they are non-living structures and, therefore, not able to& H: Q8 U: B0 w9 l) a; K
grow, repair and remodel in response to a changing environment, features which are  t" J: Q  Q- j2 U/ a. F+ Z
of particular importance in children.
+ F; q  z+ ]- S& y" b+ {5 QThe ideal heart valve replacement is autologous, engineered from material of the/ H8 {  V. E: G
patient itself to prevent immune reactions, and living to be able to grow, repair and
' G% x* K; f' K: kremodel. The emerging field of tissue engineering focuses on the engineering of such0 h( [5 \, |1 }! x' x& E9 v: S
organs. 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
7 @' O; X; |( `outside the body (in-vitro). As soon as the tissue properties are sufficient to withstand
* o; T' |" [& U1 Q0 Bin-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, the1 m. T  J8 Y) F& l
first successful replacement of one of the pulmonary valve leaflets by a tissue engineered leaflet was reported in lambs. Nowadays, complete tissue engineered valves# R$ ], l% ^; T; g' c4 t5 d
are shown to be fully functional in the pulmonary position in animal studies. The+ A6 j3 S2 [+ a8 h
pulmonary valve is, however, exposed to lower pressures and flows than the aortic2 g5 a* X5 `2 L1 {1 B
valve. A valve, able to resist the pressures and flows in the aortic position has not yet
. X/ ~% R3 g7 {% U7 ?, i' B0 t0 Qbeen created, using the principle of tissue engineering and a relatively fast degrading$ V; U3 y, t5 z3 L) c* t9 @4 f
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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！