الفهرس 
VON WILLEBRAND FACTOROnly 14 pages are availabe for public view
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Abstract
O
ver the last 20 years, investigators have gained much insight into the structure and function of vWF by studying its molecular and cellular biology. Such studies have helped us to understand the clinical manifestations of vWF and develop assays for laboratory diagnosis, the classification of vWD and its variants, and the rationale for therapy.
VWF is a large multimeric glycoprotein present in blood plasma and produced by the endothelium and subendothelial connective tissue.
vWF plays an important role in primary hemostasis at sites of vascular trauma or injury Platelet subendothelial adhesion by acting as a bridge between platelet receptors and subendothelial structures (Mendolicchio and Ruggeri, 2005).
Chronic liver diseases (CLDs) are characterized by progressive destruction and regeneration of the liver parenchyma leading to fibrosis and cirrhosis. Clinically it is defined as any hepatitis lasting for 6 months or longer (Goldberg, 2009).
Whatever the etiology, the fibrogenic processes within the liver share similar features including the presence of an inflammatory state due to infiltrating leukocytes and macrophages and activation of ECM-producing cells and leads to progressive scarring and liver cirrhosis (Friedman, 2003).
This scarring is major determinant of the development of portal hypertension and organ dysfunction, and may progress to primary liver cancer (El-Sera, 2004).
Portal hypertension (PH) accounts for the major complications of liver cirrhosis, such as ascites, variceal hemorrhage and decompensation. Early diagnosis of PH is essential for the management of patients with cirrhosis. In previous studies, it has been shown that early diagnosis, leading to adequate treatment, can significantly reduce the mortality rate of PH-related complication (Thabout et al., 2011).
Endothelial dysfunction is considered as an important determinant of the increased intrahepatic vascular resistance in cirrhotic livers. von Willebrand factorantigen (vWF-Ag) is released by activated endothelial cells (ECs) and therefore represents an indicator of EC activation and plays a crucial role in high shear stress, depending on primary hemostasis. Furthermore, in patients with liver cirrhosis, elevated levels of vWF-Ag are frequently observed.
For the purpose of the current study, we recruited on 30 patients with liver cirrhosis attending Ain Shams University Hospitals.
A cohort of 20 apparently healthy people was included as control.
Measurement of portal flow velocity of the studied patients revealed values ranging from 7 cm/sec to 13 cm/sec with median 10.5 and measurement of vWF Ag level revealed values ranging from 110 U/dl to 330 U/dl with the median of 267 while Measurement of the portal vein velocity of the control group revealed values ranging from 13 cm/sec to 20 cm/sec with median of 14 and measurement of vWFAg level revealed values ranging from 10U/dl to 50U/dl with median of 26.5 with a highly significant difference between the two groups as regards the age (p value 0.001), vWF (p value 0) and PFV (p value 0) while there was no significant difference as regards the sex.
also we found that vwf significantly increase with patients with ascitis and shrunken liver versus the other group including patients with neither ascitis nor shrunken liver.While there is no significant decrease in vWF as regards patients with varices versus the other group with no varices.
In conclusion, our study show an impressive correlation between portal velocity and vWF-Ag levels, Thus, vWF-Ag can be used for the selection of high-risk patients. We additionally could show that the reported increase of vWF-Ag is probably more related to PH, because patients with cirrhosis without PH had only slightly elevated vWF-Ag levels.