Biology of Coagulation and Coagulopathy in Neurologic Surgery

Glycemia and Coagulation in Patients with Glioblastomas

BACKGROUND

Glioblastomas are among the most malignant tumors which, despite aggressive treatment, currently have an abysmal prognosis. These lesions are known to cause local and systemic perturbations in the coagulation system, leading to neoangiogenesis and a high risk of venous thromboembolism. Indeed, there have been multiple proposals of the coagulation system being a possible target for future treatment of these patients. However, nonselective anticoagulant therapy has proven suboptimal and leads to a significant increase of intracranial hemorrhage. Thus, recognizing factors that lead to hypercoagulation is considered paramount. Hyperglycemia is a well-known prothrombotic factor, a fact that has received little attention in neuro-oncology. We previously hypothesized that patients with brain tumors could be highly susceptible to iatrogenic glycemia dysregulation. Here, we analyzed the connection between glycated hemoglobin (HbA1c) and the routine coagulation markers (D-dimers, prothrombin time and activated partial thromboplastin time [aPTT]) in patients with de novo intracranial glioblastomas.

METHODS

Included in this study were 74 patients who were operated on in 2 hospitals: Clinical Hospital Dubrava, Zagreb, Croatia; University Hospital Center Split, Split, Croatia; and University Hospital de la Princesa, Madrid, Spain.

RESULTS

We found a significant inverse correlation between HbA1c and aPTT (ρ = -0.379; P = 0.0009). We also found a significant inverse correlation between Ki67 immunoreactivity and aPTT (ρ = -0.211; P = 0.0082). No connection was found between HbA1c and D-dimers or prothrombin time.

CONCLUSIONS

Our results suggest that patients with hyperglycemia, with a more proliferative glioblastoma, could in fact have their coagulation profile significantly disrupted, primarily through the intrinsic coagulation pathway. Such findings could have great clinical importance. Further research in this area could help to elucidate the vicious connection between glioblastomas and coagulation and to combat this deadly disease.

Emicizumab promotes factor Xa generation on endothelial cells

BACKGROUND

Until recently, the treatment of hemophilia A relied on factor (F)VIII replacement. However, up to one-third of patients with severe hemophilia A develop neutralizing alloantibodies that render replacement therapies ineffective. The development of emicizumab, a bispecific antibody that partially mimics FVIIIa, has revolutionized the treatment of these patients. However, the use of an activated prothrombin complex concentrate [FEIBA (Takeda)] to treat breakthrough bleeding in patients on emicizumab has been associated with thrombotic complications including a unique microangiopathy.

OBJECTIVES

We hypothesized that the thrombotic complications observed with the combination of emicizumab and FEIBA might be due to excessive expression of procoagulant activity on the surface of endothelial cells.

METHODS

We examined the ability of emicizumab to promote FX activation on endothelial cells using 2 cell culture models.

RESULTS

We found that endothelial cells readily support emicizumab-mediated activation of FX by FIXa. The level of FXa generation depends on the concentration of available FIXa. The addition of FEIBA to emicizumab increased FXa generation in a dose-dependent manner on endothelial cells in both models. The rate of FXa generation was further enhanced by endothelial cell activation. However, unlike emicizumab, we found limited FXa generation in the presence of FVIII(a), which followed a significant lag time and was not dependent on FIXa concentration under these conditions.

CONCLUSION

Emicizumab promotes FXa generation on the surface of endothelial cells, which is markedly enhanced in the presence of FEIBA. These findings demonstrate a potential mechanism for the thrombotic complications seen with the combined use of emicizumab and FEIBA.

Research Priorities for Plasma and Platelet Transfusion Strategies in Critically Ill Children: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present a list of high-priority research initiatives for the study of plasma and platelet transfusions in critically ill children from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill pediatric patients at risk of bleeding and receiving plasma and/or platelet transfusions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of 13 experts developed research priorities for the study of plasma and platelet transfusions in critically ill children which were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding experts. The specific priorities focused on the following subpopulations: severe trauma, traumatic brain injury, intracranial hemorrhage, cardiopulmonary bypass surgery, extracorporeal membrane oxygenation, oncologic diagnosis or stem cell transplantation, acute liver failure and/or liver transplantation, noncardiac surgery, invasive procedures outside of the operating room, and sepsis and/or disseminated intravascular coagulation. In addition, tests to guide plasma and platelet transfusion, as well as component selection and processing, were addressed. We developed four general overarching themes and 14 specific research priorities using modified Research and Development/University of California, Los Angeles methodology.

CONCLUSIONS

Studies are needed to focus on the efficacy/harm, dosing, timing, and outcomes of critically ill children who receive plasma and/or platelet transfusions. The completion of these studies will facilitate the development of evidence-based recommendations.

Prediction of persistent ventricular dilation by initial ventriculomegaly and clot volume in a porcine model

OBJECTIVE

While intraventricular hemorrhage (IVH) is associated with posthemorrhagic ventricular dilation (PHVD), not all infants affected by high-grade IVH develop PHVD. The authors aimed to determine clot-associated predictors of PHVD in a porcine model by varying the amount and rate of direct intraventricular injection of whole autologous blood.

METHODS

Seven 1-week-old piglets underwent craniectomy and injection of autologous blood into the right lateral ventricle. They survived for a maximum of 28 days. MRI was performed prior to injection, immediately postoperatively, and every 7 days thereafter. T1-weighted, T2-weighted, and susceptibility-weighted imaging (SWI) sequences were used to segment ventricular and clot volumes. Spearman correlations were used to determine the relationship between blood and clot volumes and ventricular volumes over time.

RESULTS

The maximum ventricular volume was up to 12 times that of baseline. One animal developed acute hydrocephalus on day 4. All other animals survived until planned endpoints. The interaction between volume of blood injected and duration of injection was significantly associated with clot volume on the postoperative scan (p = 0.003) but not the amount of blood injected alone (p = 0.38). Initial postoperative and day 7 clot volumes, but not volume of blood injected, were correlated with maximum (p = 0.007 and 0.014) and terminal (p = 0.014 and 0.036) ventricular volumes. Initial postoperative ventricular volume was correlated with maximum and terminal ventricular volume (p = 0.007 and p = 0.014).

CONCLUSIONS

Initial postoperative, maximum, and terminal ventricular dilations were associated with the amount of clot formed, rather than the amount of blood injected. This supports the hypothesis that PHVD is determined by clot burden rather than the presence of blood products and allows further testing of early clot lysis to minimize PHVD risk.

Nanocomposite adhesive hydrogels: from design to application

Hydrogels may exhibit strong adhesion upon embedding nanoparticles into them forming strong/weak bonds (via the multiple physical or chemical interactions).

Histological and toxicological evaluation, in rat, of a P-glycoprotein inducer and activator: 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5)

P-glycoprotein (P-gp) is an ATP-binding cassette transporter involved in the efflux of numerous compounds that influences the pharmacokinetics of xenobiotics. It reduces intestinal absorption and exposure of target cells to toxicity. Thioxanthones are compounds able to induce and/or activate P-gp in vitro. Particularly, 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) behaves as a P-gp inducer and activator in vitro. The aims of this study were: i) to perform a histological characterization, by testing a single high dose of TX5 [30 mg/kg, body weight (b.w.), gavage], administered to Wistar Han rats, 24 hours after administration; and ii) to perform both a complete histological characterization and a preliminary safety evaluation, in distinct target organs, 24 hours after administration of a single lower dose of TX5 (10 mg/kg, b.w., gavage) to Wistar Han rats. The results showed a relevant histological toxicity for the higher dose of TX5 administered (30 mg/kg, b.w.), manifested by extensive hepatic necrosis and splenic toxicity (parenchyma with hyperemia, increased volume of both white and red pulp, increased follicles marginal zone). Moreover, in the kidneys, a slight hyperemia and tubular edema were observed in TX5-treated animals, as well as an inflammation of the small intestine. On the contrary, for the lower tested dose (10 mg/kg, b.w.), we did not observe any relevant histological toxicity in the evaluated organs. Additionally, no significant differences were found in the ATP levels between TX5-exposed and control animals in any of the evaluated organs, with the exception of the intestine, where ATP levels were significantly higher in TX5-treated rats. Similarly, TX5 caused a significant increase in the ratio GSH/GSSG only in the lungs. TX5 (10 mg/kg, b.w.) did not induce any change in any of the hematological and biochemical circulating evaluated parameters. However, TX5 was able to significantly reduce the activated partial thromboplastin time, without affecting the prothrombin time. The urine biochemical analysis revealed a TX5-mediated increase in both creatinine and sodium. Taken together, our results show that TX5, at a dose of 10 mg/kg, does not induce considerable toxicity in the biological matrices studied. Given this adequate safety profile, TX5 becomes a particularly interesting compound for ex vivo and in vivo studies, regarding the potential for induction and activation of P-gp at the intestinal barrier.