Thrombosis and Atherosclerosis Research Institute TaARI

Hamilton, Canada

Thrombosis and Atherosclerosis Research Institute TaARI

Hamilton, Canada

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Dwivedi D.J.,McMaster University | Dwivedi D.J.,Thrombosis and Atherosclerosis Research Institute TaARI | Toltl L.J.,McMaster University | Toltl L.J.,Thrombosis and Atherosclerosis Research Institute TaARI | And 13 more authors.
Critical Care | Year: 2012

Introduction: Although sepsis is the leading cause of death in noncoronary critically ill patients, identification of patients at high risk of death remains a challenge. In this study, we examined the incremental usefulness of adding multiple biomarkers to clinical scoring systems for predicting intensive care unit (ICU) mortality in patients with severe sepsis.Methods: This retrospective observational study used stored plasma samples obtained from 80 severe sepsis patients recruited at three tertiary hospital ICUs in Hamilton, Ontario, Canada. Clinical data and plasma samples were obtained at study inclusion for all 80 patients, and then daily for 1 week, and weekly thereafter for a subset of 50 patients. Plasma levels of cell-free DNA (cfDNA), interleukin 6 (IL-6), thrombin, and protein C were measured and compared with clinical characteristics, including the primary outcome of ICU mortality and morbidity measured with the Multiple Organ Dysfunction (MODS) score and Acute Physiology and Chronic Health Evaluation (APACHE) II scores.Results: The level of cfDNA in plasma at study inclusion had better prognostic utility than did MODS or APACHE II scores, or the biomarkers measured. The area under the receiver operating characteristic (ROC) curves for cfDNA to predict ICU mortality is 0.97 (95% CI, 0.93 to 1.00) and to predict hospital mortality is 0.84 (95% CI, 0.75 to 0.94). We found that a cfDNA cutoff value of 2.35 ng/μl had a sensitivity of 87.9% and specificity of 93.5% for predicting ICU mortality. Sequential measurements of cfDNA suggested that ICU mortality may be predicted within 24 hours of study inclusion, and that the predictive power of cfDNA may be enhanced by combining it with protein C levels or MODS scores. DNA-sequence analyses and studies with Toll-like receptor 9 (TLR9) reporter cells suggests that the cfDNA from sepsis patients is host derived.Conclusions: These studies suggest that cfDNA provides high prognostic accuracy in patients with severe sepsis. The serial data suggest that the combination of cfDNA with protein C and MODS scores may yield even stronger predictive power. Incorporation of cfDNA in sepsis risk-stratification systems may be valuable for clinical decision making or for inclusion into sepsis trials. © 2012 Dwivedi et al.; licensee BioMed Central Ltd.


Elit L.M.,McMaster University | Lee A.Y.,University of British Columbia | Parpia S.,McMaster University | Swystun L.L.,McMaster University | And 7 more authors.
Thrombosis Research | Year: 2012

Objective: Low molecular weight heparin reduces the risk of venous thromboembolism (VTE) and may have antineoplastic effects by interfering with angiogenesis and with tumor growth and metastasis. A multicentre phase II randomized trial was done to evaluate the antineoplastic potential of dalteparin in ovarian cancer (OC). Materials and Methods: Women with newly-diagnosed epithelial OC were randomized to receive standard chemotherapy (CT) and one of 3 doses of dalteparin (50 IU/kg, 100 IU/kg, or 150 IU/kg) subcutaneously once daily during the first 3 of 6 cycles of 3-weekly CT. Blood was drawn on day 1 of each cycle for CA125 and, in a substudy of randomized patients, for markers of coagulation activation and angiogenesis. The primary outcome was tumor response defined by ≥ 50% reduction in serum CA125 from baseline sustained for at least 28 days. Patients were followed until the end of CT. Results: The study was terminated early due to poor recruitment. Seventy-seven women were evaluable for the primary outcome. A 50% drop in CA125 at the end of cycle 3 was seen in 85% of the 50 IU/kg group, 92% of the100 IU/kg group, and 85% of the 150 IU/kg group. There were no symptomatic VTE or major bleeding events while on dalteparin. Two patients experienced VTE several days after discontinuing study drug. Women on dalteparin had lower levels of D-dimer and thrombin-antithrombin, and higher levels of tissue factor pathway inhibitor, relative to baseline. Conclusion: Dalteparin is safe and well tolerated in women receiving CT for newly-diagnosed epithelial OC. A dose-response effect was not identified. The lack of control group precluded any inference on the antineoplastic effect of dalteparin. © 2012 Elsevier Ltd. All rights reserved.


Swystun L.L.,McMaster University | Swystun L.L.,Thrombosis and Atherosclerosis Research Institute TaARI | Mukherjee S.,McMaster University | Liaw P.C.,Thrombosis and Atherosclerosis Research Institute TaARI | Liaw P.C.,McMaster University
Journal of Thrombosis and Haemostasis | Year: 2011

Background: Thrombosis is a common complication for breast cancer patients receiving chemotherapy. However, the mechanisms by which breast cancer chemotherapeutic agents increase this risk are largely uncharacterized. Nucleic acids released by injured cells may enhance coagulation via the activation of the contact pathway. Objectives: In this study, we examined the effects of breast cancer chemotherapy agents on the release ofcell-free DNA (CFDNA) and its relationship to thrombin generation using in vitro and in vivo methods. Methods: CFDNA release and thrombin-antithrombin (TAT) levels were measured in plasma of breast cancer patients and healthy mice receiving chemotherapy. Venous whole blood and cultured cells were exposed to chemotherapy and CFDNA release and levels of DNA-histone complexes were measured. The procoagulant activity of isolated CFDNA was measured with calibrated, automated thrombin generation. Results: Breast cancer patients receiving chemotherapy had elevated levels of CFDNA 24h post-chemotherapy, a time-point at which elevated thrombin-antithrombin levels have been previously reported. Treatment of healthy mice with doxorubicin, epirubicin and 5-fluorouracil increased CFDNA release, with a corresponding elevation in TAT complex formation. Venous whole blood and neutrophils incubated with chemotherapeutic agents had elevated CFDNA in plasma or cell supernatants. In addition, incubation of venous whole blood with chemotherapy decreased histone-DNA complex levels. CFDNA released from epirubicin-treated whole blood significantly elevated thrombin generation in a dose-dependent manner, and involved activation of the contact pathway. Conclusions: Release of CFDNA from chemotherapy-injured cells may represent a novel mechanism by which thrombosis is triggered in cancer patients. © 2011 International Society on Thrombosis and Haemostasis.


Mai S.H.C.,McMaster University | Mai S.H.C.,Thrombosis and Atherosclerosis Research Institute TaARI | Khan M.,McMaster University | Khan M.,Thrombosis and Atherosclerosis Research Institute TaARI | And 13 more authors.
Shock | Year: 2015

Sepsis is characterized by systemic activation of coagulation and inflammation in response to microbial infection. Although cell-free DNA (cfDNA) released from activated neutrophils has antimicrobial properties, it may also exert harmful effects by activating coagulation and inflammation. The authors aimed to determine whether deoxyribonuclease (DNase) administration reduces cfDNA levels, attenuates coagulation and inflammation, suppresses organ damage, and improves outcome in a cecal ligation and puncture (CLP) model of polymicrobial sepsis. Healthy C57Bl/6 mice were subjected to CLP, a surgical procedure involving two punctures of the ligated cecum, or sham surgery (no ligation/ puncture). Mice were given DNase or saline by intraperitoneal injection 2, 4, or 6 h after surgery. Two hours after treatment, organs were harvested and plasma levels of cfDNA, interleukin-6 (IL-6), IL-10, thrombin-antithrombin complexes, lung myeloperoxidase, creatinine, alanine transaminase, and bacterial load were quantified. Survival studies were also performed. The CLP-operated mice had rapid time-dependent elevations in cfDNA that correlated with elevations in IL-6, IL-10, and thrombin-antithrombin complexes and had organ damage in the lungs and kidneys. Administration of DNase at 2 h after CLP resulted in increased IL-6 and IL-10 levels and organ damage in the lungs and kidneys. In contrast,DNase administration at 4 or 6 h after CLP resulted in reduced cfDNA and IL-6 levels, increased IL-10, and suppressed organ damage and bacterial dissemination. Deoxyribonuclease administration every 6 h after CLP also rescued mice fromdeath. Our studies are the first to demonstrate that delayed but not early administration of DNase may be protective in experimental sepsis. © 2015 by the Shock Society.

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