Circulating levels of the angiogenesis mediators endoglin, HB-EGF, BMP-9 and FGF-2 in patients with severe sepsis and septic shock.

PURPOSE: Endothelial barrier dysfunction is a hallmark of sepsis, and is at least partially mediated by pathways that regulate endothelial barrier assembly during angiogenesis. Not surprisingly, increased levels of key angiogenic proteins such as VEGF-A and Angiopoietin-2 have been described in sepsis. The purpose of this study was to investigate if additional pathways that regulate endothelial barrier integrity during angiogenesis could also be involved in the host response of sepsis. MATERIAL AND METHODS: We evaluated circulating levels of four proteins involved in angiogenesis, not previously studied in sepsis, in a cohort of 50 patients with severe sepsis and septic shock. RESULTS: Circulating levels of BMP-9 and FGF-2 were similar in patients and healthy volunteers. In contrast, patients with septic shock presented 1.5-fold higher levels of endoglin (P=0.004), and 2-fold lower levels of Heparin-Binding EGF-like growth factor (HB-EGF) (P=0.002) when compared to healthy individuals. Of note, HB-EGF deficiency has been recently demonstrated to be detrimental to survival in a murine model of sepsis. CONCLUSIONS: Endoglin and HB-EGF could be involved in the host response of sepsis. Additional studies are warrant to investigate their role as biomarker or therapeutic targets in sepsis.

Tissue factor-dependent coagulation activation by heme: A thromboelastometry study.

Heme has been characterized as potent trigger of inflammation. In hemostasis, although heme has been shown to both induce and inhibit different compartments of hemostasis, its net effect on the hemostatic balance, and the biological relevance of these effects remain to be determined. Herein we evaluated the effect of heme on hemostasis using a global assay able to generate clinically relevant data in several other complex hemostatic diseases. Citrated whole blood samples from healthy participants were stimulated by heme or vehicle and incubated for 4h at 37°C. Rotational thromboelastometry was immediately performed. The participation of tissue factor in coagulation activation was evaluated using inhibitory antibody. Heme was able of inducing ex vivo coagulation activation in whole blood, affecting predominantly parameters associated with the initial phases of clot formation. This activation effect was at least partially dependent on hematopoietic tissue factor, since the effects of heme were partially abrogated by the inhibition of human tissue factor. In conclusion, using a global hemostasis assay, our study confirmed that heme is able to activate coagulation in whole blood, in a tissue factor-dependent way. These findings could explain the disturbance in hemostatic balance observed in conditions associated with the release of heme such as sickle cell disease.

A high angiopoietin-2/angiopoietin-1 ratio is associated with a high risk of septic shock in patients with febrile neutropenia.

INTRODUCTION: Endothelial barrier breakdown is a hallmark of septic shock, and proteins that physiologically regulate endothelial barrier integrity are emerging as promising biomarkers of septic shock development. Patients with cancer and febrile neutropenia (FN) present a higher risk of sepsis complications, such as septic shock. Nonetheless, these patients are normally excluded or under-represented in sepsis biomarker studies. The aim of our study was to validate the measurement of a panel of microvascular permeability modulators as biomarkers of septic shock development in cancer patients with chemotherapy-associated FN. METHODS: This was a prospective study of diagnostic accuracy, performed in two distinct in-patient units of a university hospital. Levels of vascular endothelial growth factor A (VEGF-A), soluble fms-like tyrosine kinase-1 (sFlt-1) and angiopoietin (Ang) 1 and 2 were measured after the onset of neutropenic fever, in conditions designed to mimic the real-world use of a sepsis biomarker, based on our local practice. Patients were categorized based on the development of septic shock by 28 days as an outcome. RESULTS: A total of 99 consecutive patients were evaluated in the study, of which 20 developed septic shock and 79 were classified as non-complicated FN. VEGF-A and sFlt-1 levels were similar between both outcome groups. In contrast, Ang-2 concentrations were increased in patients with septic shock, whereas an inverse finding was observed for Ang-1, resulting in a higher Ang-2/Ang-1 ratio in patients with septic shock (5.29, range 0.58 to 57.14) compared to non-complicated FN (1.99, range 0.06 to 64.62; P = 0.01). After multivariate analysis, the Ang-2/Ang-1 ratio remained an independent factor for septic shock development and 28-day mortality. CONCLUSIONS: A high Ang-2/Ang-1 ratio can predict the development of septic shock in cancer patients with febrile neutropenia.