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Levels of Von Willebrand Factor Multimers and VWF-Cleaving Protease (ADAMTS-13) in Preterm and Neonate

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ClinicalTrials.gov Identifier: NCT00701610
Recruitment Status : Unknown
Verified July 2007 by Sheba Medical Center.
Recruitment status was:  Recruiting
First Posted : June 19, 2008
Last Update Posted : June 19, 2008
Sponsor:
Information provided by:
Sheba Medical Center

Tracking Information
First Submitted Date June 18, 2008
First Posted Date June 19, 2008
Last Update Posted Date June 19, 2008
Study Start Date August 2007
Estimated Primary Completion Date August 2008   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures Not Provided
Original Primary Outcome Measures Not Provided
Change History No Changes Posted
Current Secondary Outcome Measures Not Provided
Original Secondary Outcome Measures Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title Levels of Von Willebrand Factor Multimers and VWF-Cleaving Protease (ADAMTS-13) in Preterm and Neonate
Official Title Levels of Von Willebrand Factor Multimers and VWF-Cleaving Protease (ADAMTS-13) in Preterm and Neonate
Brief Summary

Von Willebramd Factor (VWF) is an adhesive glycoprotein synthesized by megakaryocytes and endothelial cells.VWF has a central role in primary hemostasis and is a critical ligand for platelets adhesion and aggregation (1, 2).VWF is the carrier of circulating factor 8 as well. VWF is stored in Wiebel-Palade bodies in endothelial cells and in platelets alfa granules in a form of Ultra-large (UL) multimers.

The VWF multimers are composed from subunits which are linked by disulfide bonds that alternate between 2 C- terminal ends and 2 N- terminal ends in a head-to-head and tail-to-tail fashion (3, 4). The biological activity of VWF has been shown to be related to the size of the multimers.

VWF is released from endothelial cells toward the plasma as a multimers ranging from 500-20,000 kD. The UL multimers are hemostaticallly more effective than the smaller forms. They spontaneously bind to platelets which lead to the formation of microthrombi in the circulation. This mechanism is downregulated by the plasma protease ADAMTS-13(A Disintegrin And Metalloprotease with ThromboSpondin motif).If the proteolysis become defective the ULVWF will bind to platlets resulting in systemic thrombotic microangiophaties (TMA) such as thrombotic thrombocytopenic purpura(TTP)(5,6).

ADAMTS-13 belongs to the ADAMTS family of metalloproteases.The structure of ADAMTS-13 is conserved throughout vertebrates, indicating its important function (7).The metalloprotease function was first describe 11 years ago and has been cloned and characterized (8-13).The ADAMTS family of metaloploproteases is required in other systems such as genitourinary system (ADAMTS1), collagen system (ADAMTS2) and as a cleaving protease of VWF (VWFCP) - ADAMTS13. When VWF multimer is subjected to sufficient fluid shear stress ADAMTS-13 cleaves VWF at a unique 842Tyr- 843Met bond in domain A2 (14,15).This cleavage produce VWF subunit fragments of 176 kDa and 140 kDa.

The activity of ADAMTS-13 depends on both Zn+2 and Ca+2 ions (16). Low levels or deficiency of ADAMTS-13 is seen in patient with TTP(17,18). Mannuccio et al (19) showed that low levels of ADAMTS-13 are seen in other conditions such as healthy adults older than 65 years, patients with cirrhosis, uremia, acute inflammation, postoperative period. In neonate and preterm infants the data is limited. Few studies have shown that levels of ADAMTS-13 are low in neonate (19-21).Tsai et al (22) observed that ADAMTS-13 activity is normal in cord blood compared to adults. In preterm infants a pilot study showed that preterm have low levels of ADAMTS-13(23).

The aim of our study is to check ADAMTS-13, VWF multimers, VWF antigen and VWF collagen binding activity in healthy and sick neonate and in preterm infants.

Detailed Description Not Provided
Study Type Observational
Study Design Observational Model: Cohort
Time Perspective: Prospective
Target Follow-Up Duration Not Provided
Biospecimen Retention:   Samples Without DNA
Description:
blood will be taken from cord blood at birth from fullterm and preterm infantsinfants
Sampling Method Non-Probability Sample
Study Population All infants born n our hospital between August 2007 and August 2009 will enter
Condition Von Willebramd Factor
Intervention Not Provided
Study Groups/Cohorts 1
All infants born in our hospital between August 2007 and August 2009 will participate.
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status Unknown status
Estimated Enrollment
 (submitted: June¬†18,¬†2008)
100
Original Estimated Enrollment Same as current
Estimated Study Completion Date August 2009
Estimated Primary Completion Date August 2008   (Final data collection date for primary outcome measure)
Eligibility Criteria

Inclusion Criteria:

  • All infants born n our hospital between August 2007 and August 2009 will enter

Exclusion Criteria:

  • Thrombocytopenia, maternal aspirin
Sex/Gender
Sexes Eligible for Study: All
Ages 24 Weeks to 42 Weeks   (Child)
Accepts Healthy Volunteers No
Contacts Contact information is only displayed when the study is recruiting subjects
Listed Location Countries Israel
Removed Location Countries  
 
Administrative Information
NCT Number NCT00701610
Other Study ID Numbers SHEBA-08-4132-TS-CTIL
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement Not Provided
Responsible Party Tzipora Strauss, Sheba Medical Center
Study Sponsor Sheba Medical Center
Collaborators Not Provided
Investigators Not Provided
PRS Account Sheba Medical Center
Verification Date July 2007