溫韋伯氏因子(Von Willebrand factor)


資料來源:medicinembbs
 Von Willebrand factor為穩固collagen和platelet的物質。Collagen上有Von Willebrand factor,而platelet上的醣蛋白GpIb(Gp=glycoprotein)可與Von Willebrand factor結合,所以platelet可和collagen穩固地結合
 ADP會誘導platelet表面形成GpIIb-IIIa complex,GpIIb-IIIa complex藉由fibrinogen的幫助下連結更多的platelet而形成小血板栓塞(platelet plug)。
 有些抗凝血劑是作用在GpIIb-IIIa complex,使其不能形成而達到效果。
▼血液(blood) 顯示/隱藏(show/hide)

5 意見:

  1. 請問,我看圖片是指穩固內皮細胞與血小板結合,那在本文章的敘述中的與膠原蛋白結合是指?

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    1. VWF 存在於內皮細胞與內皮下基質,會和血小板表面的GPⅠb-Ⅸ-V complex結合,而這個complex的其中一個次單位GPⅠbα朝向細胞質的部分會和細胞內的膠原蛋白結合,另外,膠原蛋白上也有VWF
      所以就是在說,這個GPⅠb complex和VWF可以結合,不管是血小板外的內皮細胞上的VWF,還是血小板裡面的collagen,都可以結合。

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    2. 小小整理網站您好,不好意思想請問一下,我發現您上述對於vWf的論述與我在原文書(Vander's及Pearson)上看到的敘述不太符合,您上述說vWf是原先即存在於內皮細胞、內皮下層組織(含膠原蛋白基質),是由於血管破裂露出後,才引發血小板過來結合聚集,形成血小板栓(platelet plug),以及後續你對上述大大的這段回話:「這個GPⅠb complex和VWF可以結合,不管是血小板外的內皮細胞上的VWF,還是血小板裡面的collagen,都可以結合。」,我想有點怪異,照您的說法,血小板只要經過內皮細胞就會結合到其上的vWf,所以在整條血管內會到處聚集...XD 然後血小板是細胞碎片,裡面怎會有collagen呢...
      以下是我在兩本原文書截出的內容,希望可以供您參考與修正:
      1. Vander's (12th P.422): Injury to a vessel disrupts the endothelium and exposes the underlying connective-tissue collagen fibers. Platelets adhere to collagen, largely via an intermediary called von Willebrand factor(vWF), a plasma protein secreted by endothelial cells and platelets. This protein binds to exposed collagen molecules, changes its conformation, and becomes able to bind platelets. Thus, vWF forms a bridge between the damaged vessel wall and the platelets.
      2. Pearson (5th P.485-486): Both the formation of platelet plugs and the subsequent blood clot require the presence of platelets and "a fairly large set of specific plasma proteins". In platelet plug formation, the key protein is von Willebrand factor(vWf), which is secreted by megakaryocytes, platelets, and endothelial cells lining blood vessels. Although vWf is present in the plasma at all times, it accumulates at the site of vessel damage. The first step in platelet plug formation is platelet adhesion, which occurs when blood vessel damage exposes the tissue underlying the endothelium, called subendothelial tissue. "When blood contacts subendothelial tissue, vWf binds to collagen fibers in the subendothelium, triggering the binding of platelets to vWf, which anchors platelets in place."
      (英文純手打好累 哈哈 但是貢獻給我超喜歡且敬愛的小小整理網站很值得XD)

      綜合上述可知,vWF(或vWf)應是由內皮細胞、血小板、巨核細胞(Pearson提到)所分泌,且平常就會出現在血液當中(即血漿蛋白之一),一直要等到血管破損露出底下collagen fibers,vWf才會與膠原蛋白結合,進而改變其構型後,才能引發血小板結合在vWf上,即「血小板-vWf-膠原纖維」連結關係,因此Vander's才會說:vWF在受損血管壁及血小板之間形成一道連結橋梁。
      我覺得這樣的論述比較合理,以此僅供小小整理網站大大們參考(叩拜。

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    3. Lili 上面那個不一定是小小整理網站回的吧

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    4. 這倒也是,不過也沒關係,就當大家一起討論,以求正確的學識觀念囉! :D

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