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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The aortic heart valve, situated between the aorta and the left ventricle, is one of the
  Y, u+ O1 l( N7 [3 sfour valves in the heart controlling the blood flow (chapter 1). It consists of three
, E) g) X$ Z  F9 K! Vleaflets, with sufficient coaptation areas to ensure closure of the valve. The valve) y8 P( _4 d( W0 i* z  N
opens and closes about 3.7 billion times in a lifetime, requiring strength, flexibility,2 E; ]- X% v2 j# }/ [2 U
and durability of the tissue. For this imposing function, the leaflets have a highly1 H; \" H8 I0 J5 O( ]. v3 ^
organized and specific tissue structure. When valve function is impaired, for example by calcification of the leaflets or inherited diseases, a live-threatening situation
5 w2 C; x3 B# ?# h9 uoccurs as insufficient oxygen is being supplied to the body. A common treatment
8 n& q5 }3 h4 j+ t/ q6 Mis 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
8 k# o  @* @' Z# M* a* D6 _having such a valve implanted, require lifelong anticoagulation therapy to prevent
/ v$ A: y8 G4 p' Ythrombo-embolism, the formation of blood clots on the surface of the valve leaflets.
" S. z* n3 ^# I8 X4 g4 K0 e0 UThis treatment itself results in increased risks of internal bleedings. Patients with a
; z' e/ b4 b% o5 \1 Cbioprosthetic valve, for example a glutaraldehyde-treated porcine valve or a cryopreserved human donor valve, do not face anticoagulation therapy. The drawback of
3 |2 |1 a7 _; u/ ^9 K  S* |this type of heart valve replacement is that they are less durable caused by enhanced: }+ h8 y& ^$ O* j! F
calcification and immune reactions of the body. All heart valve replacements share1 Q9 [7 z0 w/ B/ |1 Z* v9 L
the major disadvantage that they are non-living structures and, therefore, not able to
; H1 r8 k& \' _( d& w8 ugrow, repair and remodel in response to a changing environment, features which are
5 J3 O0 R' k4 `$ n1 Q6 B* Rof particular importance in children.7 V+ Z! i+ I9 S2 L
The ideal heart valve replacement is autologous, engineered from material of the4 @0 m  l$ z+ V& Y- M/ H8 j5 H# m
patient itself to prevent immune reactions, and living to be able to grow, repair and0 ^* D# I! R, I. W$ o+ W3 p' H
remodel. The emerging field of tissue engineering focuses on the engineering of such! @- n8 Y4 n& X& q8 F, E
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
  w$ U) T9 m, J+ [9 Y# ooutside the body (in-vitro). As soon as the tissue properties are sufficient to withstand
% B5 Z# N  {5 u% U& M1 l/ Lin-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) {- \% f" `4 [
first successful replacement of one of the pulmonary valve leaflets by a tissue engineered leaflet was reported in lambs. Nowadays, complete tissue engineered valves
) `* P6 C2 H% x4 a& r# h! Yare shown to be fully functional in the pulmonary position in animal studies. The
2 ~; g9 U5 v3 b* }: V$ tpulmonary valve is, however, exposed to lower pressures and flows than the aortic
+ k/ L; v4 F+ \( `1 G0 o/ kvalve. A valve, able to resist the pressures and flows in the aortic position has not yet1 V" p9 C6 L* k7 t/ d1 p
been created, using the principle of tissue engineering and a relatively fast degrading- R+ T) n( l. t% D2 i& d
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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！