Faculty Collaboration Database

Von Willebrand factor is reversibly decreased during torpor in 13-lined ground squirrels. J Comp Physiol B 2016 Jan;186(1):131-9

Date

10/21/2015

Pubmed ID

26481634

Pubmed Central ID

PMC4838567

DOI

10.1007/s00360-015-0941-5

Scopus ID

2-s2.0-84953368104 (requires institutional sign-in at Scopus site)   16 Citations

Abstract

During torpor in a hibernating mammal, decreased blood flow increases the risk of blood clots such as deep vein thrombi (DVT). In other animal models platelets, neutrophils, monocytes and von Willebrand factor (VWF) have been found in DVT. Previous research has shown that hibernating mammals decrease their levels of platelets and clotting factors VIII (FVIII) and IX (FIX), increasing both bleeding time and activated partial thromboplastin time. In this study, FVIII, FIX and VWF activities and mRNA levels were measured in torpid and non-hibernating ground squirrels (Ictidomys tridecemlineatus). Here, we show that VWF high molecular weight multimers, collagen-binding activity, lung mRNA and promoter activity decrease during torpor. The VWF multimers reappear in plasma within 2 h of arousal in the spring. Similarly, FIX activity and liver mRNA both dropped threefold during torpor. In contrast, FVIII liver mRNA levels increased twofold while its activity dropped threefold, consistent with a post-transcriptional decrease in FVIII stability in the plasma due to decreased VWF levels. Finally, both neutrophils and monocytes are decreased eightfold during torpor which could slow the formation of DVT. In addition to providing insight in how blood clotting can be regulated to allow mammals to survive in extreme environments, hibernating ground squirrels provide an interesting model for studying.

Author List

Cooper S, Sell S, Nelson L, Hawes J, Benrud JA, Kohlnhofer BM, Burmeister BR, Flood VH

Authors

Bradley R. Burmeister MD Adjunct Assistant Professor in the Medical School Regional Campuses department at Medical College of Wisconsin
Veronica H. Flood MD Chief, Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Blood Coagulation
Factor IX
Factor VIII
Gene Expression Regulation
RNA, Messenger
Sciuridae
Seasons
Torpor
von Willebrand Factor