title: Contraction of Blood Clots Is Impaired in Acute Ischemic Stroke.
abstract: OBJECTIVE
  Obstructive thrombi or thrombotic emboli are the pathogenic basis of ischemic stroke. In vitro blood clots and in vivo thrombi can undergo platelet-driven contraction (retraction), resulting in volume shrinkage. Clot contraction can potentially reduce vessel occlusion and improve blood flow past emboli or thrombi. The aim of this work was to examine a potential pathogenic role of clot contraction in ischemic stroke.
  
  
  RESULTS
  We used a novel automated method that enabled us to quantify time of initiation and extent and rate of clot contraction in vitro. The main finding is that clot contraction from the blood of stroke patients was reduced compared with healthy subjects. Reduced clot contraction correlated with a lower platelet count and their dysfunction, higher levels of fibrinogen and hematocrit, leukocytosis, and other changes in blood composition that may affect platelet function and properties of blood clots. Platelets from stroke patents were spontaneously activated and displayed reduced responsiveness to additional stimulation. Clinical correlations with respect to severity and stroke pathogenesis suggest that the impaired clot contraction has the potential to be a pathogenic factor in ischemic stroke.
  
  
  CONCLUSIONS
  The changeable ability of clots and thrombi to shrink in volume may be a novel unappreciated mechanism that aggravates or alleviates the course and outcomes of ischemic stroke. The clinical importance of clot or thrombus transformations in vivo and the diagnostic and prognostic value of this blood test for clot contraction need further exploration.
authors.affiliation: From the Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia (V.T., J.W.W., R.I.L.); School of Biomedical Engineering, Sciences, and Health Systems, Drexel University, Philadelphia, PA (V.T.); Institute of Fundamental Medicine and Biology, Kazan Federal University, Russia (A.D.P., I.A.A., R.I.L.); and Neurology Department, Interregional Clinical Diagnostic Center, Kazan, Russia (D.R.K.).
authors.forename: Valerie
authors.initials: V
authors.lastname: Tutwiler
authors.affiliation: From the Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia (V.T., J.W.W., R.I.L.); School of Biomedical Engineering, Sciences, and Health Systems, Drexel University, Philadelphia, PA (V.T.); Institute of Fundamental Medicine and Biology, Kazan Federal University, Russia (A.D.P., I.A.A., R.I.L.); and Neurology Department, Interregional Clinical Diagnostic Center, Kazan, Russia (D.R.K.).
authors.forename: Alina D
authors.initials: AD
authors.lastname: Peshkova
authors.affiliation: From the Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia (V.T., J.W.W., R.I.L.); School of Biomedical Engineering, Sciences, and Health Systems, Drexel University, Philadelphia, PA (V.T.); Institute of Fundamental Medicine and Biology, Kazan Federal University, Russia (A.D.P., I.A.A., R.I.L.); and Neurology Department, Interregional Clinical Diagnostic Center, Kazan, Russia (D.R.K.).
authors.forename: Izabella A
authors.initials: IA
authors.lastname: Andrianova
authors.affiliation: From the Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia (V.T., J.W.W., R.I.L.); School of Biomedical Engineering, Sciences, and Health Systems, Drexel University, Philadelphia, PA (V.T.); Institute of Fundamental Medicine and Biology, Kazan Federal University, Russia (A.D.P., I.A.A., R.I.L.); and Neurology Department, Interregional Clinical Diagnostic Center, Kazan, Russia (D.R.K.).
authors.forename: Dina R
authors.initials: DR
authors.lastname: Khasanova
authors.affiliation: From the Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia (V.T., J.W.W., R.I.L.); School of Biomedical Engineering, Sciences, and Health Systems, Drexel University, Philadelphia, PA (V.T.); Institute of Fundamental Medicine and Biology, Kazan Federal University, Russia (A.D.P., I.A.A., R.I.L.); and Neurology Department, Interregional Clinical Diagnostic Center, Kazan, Russia (D.R.K.).
authors.forename: John W
authors.initials: JW
authors.lastname: Weisel
authors.affiliation: From the Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia (V.T., J.W.W., R.I.L.); School of Biomedical Engineering, Sciences, and Health Systems, Drexel University, Philadelphia, PA (V.T.); Institute of Fundamental Medicine and Biology, Kazan Federal University, Russia (A.D.P., I.A.A., R.I.L.); and Neurology Department, Interregional Clinical Diagnostic Center, Kazan, Russia (D.R.K.). litvinov@mail.med.upenn.edu.
authors.forename: Rustem I
authors.initials: RI
authors.lastname: Litvinov
mesh_terms: D000328:Adult; D000368:Aged; D001777:Blood Coagulation; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000378:metabolism; D002545:Brain Ischemia / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D005260:Female; D005340:Fibrinogen; D006801:Humans; D020767:Intracranial Thrombosis / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation; D012720:Severity of Illness Index; D020521:Stroke / Q000097:blood* / Q000209:etiology / Q000503:physiopathology
chemical_list: D005340:Fibrinogen
keywords: blood coagulation; clot retraction; stroke; thrombosis