ANSWER TO QUIZ OF THE WEEK FOR MAY 25, 2007

What is it?

Niastase® contains eptacog alfa (activated), also known as activated recombinant Factor VII (rFVIIa). It is used to correct Factor VIIa deficiencies and control bleeding. It may be considered in the treatment of severe hemorrhage, or as an antidote to some anticoagulants, especially those that block the synthesis of vitamin K dependent clotting factors (e.g., warfarin).

What is a Recombinant Protein?

Recombinant refers to a form of artificial DNA which is engineered through the combination or insertion of one or more strands of DNA into an existing organismal genome. Strands that would normally not exist together can be combined, allowing specific traits to be modified.

Recombinant Factor VII is made by cloning human Factor VII (a clotting factor) and allowing it to grow in baby hamster kidney cells (BHK cells). During the process of purification, the rFVIIa is converted to the activated form. It is free of all human plasma components, therefore, does not carry any risk for viral transmission.

What is Human Factor VII?

Factor VII is an important human clotting factor. All tissue injury (including: ischemia, trauma, infection etc) triggers an immediate inflammatory response. Inflammation causes immediate activation of a number of cells including: edothelial cells (the lining cells of blood vessels), platelets and white blood cells, increasing the presence of a protein called Tissue Factor (also known as thromboplastin or Factor III). Once present, Tissue Factor quickly combines with activated Factor VII (VIIa) to initiate the clotting cascade. The Factor VIIa:Tissue Factor complex will immediately trigger the activatino of Factor Xa, a critical precursor step to the production of thrombin and fibrin.

During massive tissue injury or hemorrhage, large amounts of Tissue Factor is generated. Because Tissue Factor quickly combines with Factor VIIa to activate the clotting cascade, Factor VII can become depleted during times of extensive trauma. Consequently, there is great interest in the potential role for Factor VII in the treatment of severe hemorrhage, and it is currently being investigated through clinical trials.

Niastase may be used in patients with hemorrhage due to trauma.

See Transfusion Protocol

 

Brenda Morgan, Clinical Nurse Specialist, CCTC

References:

http://en.wikipedia.org/wiki/Recombinant_DNA

www.novonordisk.ca/PDF_Files/NiaStase.pdf

http://en.wikipedia.org/wiki/Tissue_factor

http://www.utdol.com/utd/content/topic.do?topicKey=coagulat/9319&view=print#

 

Brenda Morgan
Clinical Nurse Specialist, CCTC
Last Update: April 6 , 2007

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