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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. ?5 i$ l+ O: QThe aortic heart valve, situated between the aorta and the left ventricle, is one of the
! W: w+ V$ ^. B& R. g- T" d5 ifour valves in the heart controlling the blood flow (chapter 1). It consists of three/ b" h0 D0 m0 E1 l7 U, H. I
leaflets, with sufficient coaptation areas to ensure closure of the valve. The valve' l6 \) a: W7 x* i% K1 n! }6 D
opens and closes about 3.7 billion times in a lifetime, requiring strength, flexibility,
6 ?" g+ U* s0 c' y. C: cand durability of the tissue. For this imposing function, the leaflets have a highly8 ~! g  R" J( u& `
organized and specific tissue structure. When valve function is impaired, for example by calcification of the leaflets or inherited diseases, a live-threatening situation
, j0 I+ P3 ?5 T6 r% T6 F: Xoccurs as insufficient oxygen is being supplied to the body. A common treatment2 o7 E; m+ @( L! i2 R: B1 K
is the replacement of the aortic valve with either a mechanical valve or a bioprosthetic valve. The durability of a mechanical valve is excellent. However, patients2 g: |, N  ^5 w
having such a valve implanted, require lifelong anticoagulation therapy to prevent
2 w1 n1 i8 h, h* mthrombo-embolism, the formation of blood clots on the surface of the valve leaflets.7 P+ X& ?2 Q4 H! D1 X
This treatment itself results in increased risks of internal bleedings. Patients with a
$ R# z+ R2 b+ u" T  x1 e( ^bioprosthetic valve, for example a glutaraldehyde-treated porcine valve or a cryopreserved human donor valve, do not face anticoagulation therapy. The drawback of% s( H. ?; H8 T# C6 c* N# s* |
this type of heart valve replacement is that they are less durable caused by enhanced
2 t( h. h! g6 g( `6 h4 L2 v+ zcalcification and immune reactions of the body. All heart valve replacements share; L$ O2 l/ g+ I5 U; V' d8 H; ]
the major disadvantage that they are non-living structures and, therefore, not able to  l: L! ~! M" L$ r" V
grow, repair and remodel in response to a changing environment, features which are
* W) m. C' a$ D: Y. Xof particular importance in children.9 p9 K5 I3 f( [
The ideal heart valve replacement is autologous, engineered from material of the
8 `) F0 C4 s! f9 ?; v  w, tpatient itself to prevent immune reactions, and living to be able to grow, repair and
% o* N" a/ W7 Z8 Lremodel. The emerging field of tissue engineering focuses on the engineering of such
& q, U1 |2 W) Q' ]/ f% @7 Worgans. 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 developing8 J- e8 ?, [9 N' g/ |) s
outside the body (in-vitro). As soon as the tissue properties are sufficient to withstand+ x; z# t! o4 P) B, K! n) N0 ?) ?, C
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* Q% q9 d% R, a8 p& K( C" Q! B, C
first successful replacement of one of the pulmonary valve leaflets by a tissue engineered leaflet was reported in lambs. Nowadays, complete tissue engineered valves
! d6 [; a: V6 ]) f4 }are shown to be fully functional in the pulmonary position in animal studies. The3 [0 H: e# x+ L. J3 Q1 v
pulmonary valve is, however, exposed to lower pressures and flows than the aortic
5 e' y( T$ l( N7 V8 E, E9 u# F4 a6 tvalve. A valve, able to resist the pressures and flows in the aortic position has not yet5 T7 t& u" V, x5 b
been created, using the principle of tissue engineering and a relatively fast degrading
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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！