Endothelial Activation and Stress Index in adults undergoing allogeneic hematopoietic cell transplantation with post-transplant cyclophosphamide-based prophylaxis.

BACKGROUND AIMS: Post-transplant cyclophosphamide (PTCY)-based prophylaxis is becoming widespread for allogeneic hematopoietic cell transplantation (allo-HCT) performed independently of the selected donor source. In parallel, use of the Endothelial Activation and Stress Index (EASIX)-considered a surrogate parameter of endothelial activation-for predicting patient outcomes and clinical complications is gaining popularity in the allo-HCT setting. METHODS: We first investigated whether the dynamics of EASIX after allo-HCT differ between patients receiving PTCY and patients receiving other prophylaxis. We then investigated whether the predictive capacity of EASIX persists in PTCY-based allo-HCT. A total of 328 patients transplanted between 2014 and 2020 were included, and 201 (61.2%) received PTCY. RESULTS: EASIX trends differed significantly between the groups. Compared with patients receiving other prophylaxis, patients receiving PTCY had lower EASIX on day 0 and higher values between day 7 and day 100. In patients receiving PTCY, higher EASIX correlated significantly with higher non-relapse mortality (NRM) and lower overall survival (OS) when measured before and during the first 180 days after allo-HCT. In addition, higher EASIX scores measured at specific time points were predictors of veno-occlusive disease (VOD), transplant-associated thrombotic microangiopathy (TA-TMA) and grade 2-4 acute graft-versus-host disease (aGVHD) risk. CONCLUSIONS: This study demonstrates how EASIX trends vary during the first 180 days after allo-HCT in patients receiving PTCY and those not receiving PTCY and validates the utility of this index for predicting NRM, OS and risk of VOD, TA-TMA and grade 2-4 aGVHD in patients receiving PTCY.

Differential protein expression in endothelial cells exposed to serum from patients with acute graft-vs-host disease, depending on steroid response.

Graft-versus-host disease (GVHD) is a complication of allogeneic haematopoietic cell transplantation. Endothelial injury is crucial as pathophysiological substrate for GVHD. GVHD first-line treatment is high-dose corticosteroids, although some patients are steroid-refractory. Through the present study, we compared the endothelial proteomic profiles in response to serum from steroid-refractory acute GVHD (SR-aGVHD) and steroid-sensitive acute GVHD (SS-aGVHD) patients. Blood samples from SR-aGVHD (n = 4) and SS-aGVHD (n = 8) patients were collected at aGVHD diagnosis. Endothelial cell cultures were exposed (48 h) to patients' serum. Protein extraction and proteomic analysis were performed. Differences were statistically evaluated by multivariate analysis. Forty-four proteins contributed to separate all samples into the two study groups, among which 15 participated significantly (p < 0.05), 10 exhibiting a fold change >1.2. Differentially expressed proteins were mainly associated with oxidative phosphorylation (Cytochrome C oxidase subunit 6B1, CX6B1), inflammation and angiogenesis (Apolipoprotein D, APOD), cell survival (Rapamycin-insensitive companion of mTOR, RICTR), and oxidative stress (Riboflavin kinase, RIFK). This pilot study used a novel approach to distinguish the aGVHD response to steroid treatment. The proteins differentially expressed could constitute potential biomarkers for steroid-treatment response. These findings signify a step forward to identify the mechanisms of response to steroids, of high clinical relevance considering the SR-aGVHD elevated mortality.

Real-world data of the use and experience of caplacizumab for the treatment of acquired thrombotic thrombocytopenic purpura: Case series.

PURPOSE: Caplacizumab was licensed for acquired thrombotic thrombocytopenic purpura (aTTP) based on prospective controlled trials. Real-world evidence is crucial in rare diseases. We aim to describe a patient population with aTTP, receiving caplacizumab in a real-world setting, reporting their outcomes, including safety and tolerability, and contrasting them with a historical cohort from our center. METHODS: We describe data collected retrospectively from 2012 to 2022 for 16 patients with aTTP (8 received caplacizumab and 8 the historical standard-of-care). Patients' characteristics and outcomes were compared between groups. RESULTS: Patients' demographic and baseline characteristics were similar in both groups. Caplacizumab led to a rapid normalization of the platelet count of 3.5 (IQR, 2-6) versus 16 (IQR, 9.5-23.5) days in the historical cohort: (p = .002). The median number of plasma exchanges and the length of days requiring them, between the caplacizumab group versus the historical cohort, was 6 (IQR, 6-10) versus 19.5 (IQR, 12.5-29.5) plasma exchanges (p = .006); and 9 (IQR, 8.5-13.5) versus 22 (15-31) days (p = .049), respectively. There were no refractory cases in the caplacizumab group in comparison with 37.5 % in the historical cohort. None of patients treated with caplacizumab experienced a recurrence after 1081 (IQR, 511-3125) days of follow-up. Safety was in line with data reported in clinical trials, with mild adverse events (mostly grade≤2). CONCLUSION: We provided real-world evidence in the treatment of aTTP, confirming the results obtained in clinical trials. Caplacizumab reduced the time to platelet count recovery and the number and length of plasma exchanges.

Impact of different pathogen reduction technologies on the biochemistry, function, and clinical effectiveness of platelet concentrates: An updated view during a pandemic.

Standard platelet concentrates (PCs) stored at 22°C have a limited shelf life of 5 days. Because of the storage temperature, bacterial contamination of PCs can result in life-threatening infections in transfused patients. The potential of blood components to cause infections through contaminating pathogens or transmitting blood-borne diseases has always been a concern. The current safety practice to prevent pathogen transmission through blood transfusion starts with a stringent screening of donors and regulated testing of blood samples to ensure that known infections cannot reach transfusion products. Pathogen reduction technologies (PRTs), initially implemented to ensure the safety of plasma products, have been adapted to treat platelet products. In addition to reducing bacterial contamination, PRT applied to PCs can extend their shelf life up to 7 days, alleviating the impact of their shortage, while providing an additional safety layer against emerging blood-borne infectious diseases. While a deleterious action of PRTs in quantitative and qualitative aspects of plasma is accepted, the impact of PRTs on the quality, function, and clinical efficacy of PCs has been under constant examination. The potential of PRTs to prevent the possibility of new emerging diseases to reach cellular blood components has been considered more hypothetical than real. In 2019, a coronavirus-related disease (COVID-19) became a pandemic. This episode should help when reconsidering the possibility of future blood transmissible threats. The following text intends to evaluate the impact of different PRTs on the quality, function, and clinical effectiveness of platelets within the perspective of a developing pandemic.

Differences and similarities in endothelial and angiogenic profiles of preeclampsia and COVID-19 in pregnancy.

BACKGROUND: COVID-19 presents a spectrum of signs and symptoms in pregnant women that might resemble preeclampsia. Differentiation between severe COVID-19 and preeclampsia is difficult in some cases. OBJECTIVE: To study biomarkers of endothelial damage, coagulation, innate immune response, and angiogenesis in preeclampsia and COVID-19 in pregnancy in addition to in vitro alterations in endothelial cells exposed to sera from pregnant women with preeclampsia and COVID-19. STUDY DESIGN: Plasma and sera samples were obtained from pregnant women with COVID-19 infection classified into mild (n=10) or severe (n=9) and from women with normotensive pregnancies as controls (n=10) and patients with preeclampsia (n=13). A panel of plasmatic biomarkers was assessed, including vascular cell adhesion molecule-1, soluble tumor necrosis factor-receptor I, heparan sulfate, von Willebrand factor antigen (activity and multimeric pattern), α2-antiplasmin, C5b9, neutrophil extracellular traps, placental growth factor, soluble fms-like tyrosine kinase-1, and angiopoietin 2. In addition, microvascular endothelial cells were exposed to patients' sera, and changes in the cell expression of intercellular adhesion molecule 1 on cell membranes and von Willebrand factor release to the extracellular matrix were evaluated through immunofluorescence. Changes in inflammation cell signaling pathways were also assessed by of p38 mitogen-activated protein kinase phosphorylation. Statistical analysis included univariate and multivariate methods. RESULTS: Biomarker profiles of patients with mild COVID-19 were similar to those of controls. Both preeclampsia and severe COVID-19 showed significant alterations in most circulating biomarkers with distinctive profiles. Whereas severe COVID-19 exhibited higher concentrations of vascular cell adhesion molecule-1, soluble tumor necrosis factor-α receptor I, heparan sulfate, von Willebrand factor antigen, and neutrophil extracellular traps, with a significant reduction of placental growth factor compared with controls, preeclampsia presented a marked increase in vascular cell adhesion molecule-1 and soluble tumor necrosis factor-α receptor I (significantly increased compared with controls and patients with severe COVID-19), with a striking reduction in von Willebrand factor antigen, von Willebrand factor activity, and α2-antiplasmin. As expected, reduced placental growth factor, increased soluble fms-like tyrosine kinase-1 and angiopoietin 2, and a very high soluble fms-like tyrosine kinase-1 to placental growth factor ratio were also observed in preeclampsia. In addition, a significant increase in C5b9 and neutrophil extracellular traps was also detected in preeclampsia compared with controls. Principal component analysis demonstrated a clear separation between patients with preeclampsia and the other groups (first and second components explained 42.2% and 13.5% of the variance), mainly differentiated by variables related to von Willebrand factor, soluble tumor necrosis factor-receptor I, heparan sulfate, and soluble fms-like tyrosine kinase-1. Von Willebrand factor multimeric analysis revealed the absence of von Willebrand factor high-molecular-weight multimers in preeclampsia (similar profile to von Willebrand disease type 2A), whereas in healthy pregnancies and COVID-19 patients, von Willebrand factor multimeric pattern was normal. Sera from both preeclampsia and severe COVID-19 patients induced an overexpression of intercellular adhesion molecule 1 and von Willebrand factor in endothelial cells in culture compared with controls. However, the effect of preeclampsia was less pronounced than the that of severe COVID-19. Immunoblots of lysates from endothelial cells exposed to mild and severe COVID-19 and preeclampsia sera showed an increase in p38 mitogen-activated protein kinase phosphorylation. Patients with severe COVID-19 and preeclampsia were statistically different from controls, suggesting that both severe COVID-19 and preeclampsia sera can activate inflammatory signaling pathways. CONCLUSION: Although similar in in vitro endothelial dysfunction, preeclampsia and severe COVID-19 exhibit distinctive profiles of circulating biomarkers related to endothelial damage, coagulopathy, and angiogenic imbalance that could aid in the differential diagnosis of these entities.

Is the Endothelium the Missing Link in the Pathophysiology and Treatment of COVID-19 Complications?

Patients with COVID-19 present a wide spectrum of disease severity, from asymptomatic cases in the majority to serious disease leading to critical care and even death. Clinically, four different scenarios occur within the typical disease timeline: first, an incubation and asymptomatic period; second, a stage with mild symptoms due mainly to the virus itself; third, in up to 20% of the patients, a stage with severe symptoms where a hyperinflammatory response with a cytokine storm driven by host immunity induces acute respiratory distress syndrome; and finally, a post-acute sequelae (PASC) phase, which present symptoms that can range from mild or annoying to actually quite incapacitating. Although the most common manifestation is acute respiratory failure of the lungs, other organs are also frequently involved. The clinical manifestations of the COVID-19 infection support a key role for endothelial dysfunction in the pathobiology of this condition. The virus enters into the organism via its interaction with angiotensin-converting enzyme 2-receptor that is present prominently in the alveoli, but also in endothelial cells, which can be directly infected by the virus. Cytokine release syndrome can also drive endothelial damage independently. Consequently, a distinctive feature of SARS-CoV-2 infection is vascular harm, with severe endothelial injury, widespread thrombosis, microangiopathy, and neo-angiogenesis in response to endothelial damage. Therefore, endothelial dysfunction seems to be the pathophysiological substrate for severe COVID-19 complications. Biomarkers of endothelial injury could constitute strong indicators of disease progression and severity. In addition, the endothelium could represent a very attractive target to both prevent and treat these complications. To establish an adequate therapy, the underlying pathophysiology and corresponding clinical stage should be clearly identified. In this review, the clinical features of COVID-19, the central role of the endothelium in COVID-19 and in other pathologies, and the potential of specific therapies aimed at protecting the endothelium in COVID-19 patients are addressed.

Complement as the enabler of carfilzomib-induced thrombotic microangiopathy.

Carfilzomib has been associated with the development of thrombotic microangiopathy (TMA) in relapsed/refractory multiple myeloma patients, a severe disease with no currently available aetiological treatment. We evaluated the potential role of terminal complement pathway in four patients with carfilzomib-induced TMA. Membrane attack complex (C5b-9) deposition on endothelial cells in culture exposed to plasma from patients during the acute phase of the disease suggests complement overactivation as a mechanism of potential endothelial damage in three out of four patients. If confirmed in larger cohorts, C5b-9 evaluation will allow early identification of patients who could benefit from complement blockade and treatment monitoring.

Endothelial damage and dysfunction in acute graft-versus-host disease.

Clinical studies suggested that endothelial dysfunction and damage could be involved in the development and severity of acute graft-versus-host disease (aGVHD). Accordingly, we found increased percentage of apoptotic Casp3+ blood vessels in duodenal and colonic mucosa biopsies of patients with severe aGVHD. In murine experimental aGVHD, we detected severe microstructural endothelial damage and reduced endothelial pericyte coverage accompanied by reduced expression of endothelial tight junction proteins leading to increased endothelial leakage in aGVHD target organs. During intestinal aGVHD, colonic vasculature structurally changed, reflected by increased vessel branching and vessel diameter. Because recent data demonstrated an association of endothelium-related factors and steroid refractory aGVHD (SR-aGVHD), we analyzed human biopsies and murine tissues from SR-aGVHD. We found extensive tissue damage but low levels of alloreactive T cell infiltration in target organs, providing the rationale for T-cell independent SR-aGVHD treatment strategies. Consequently, we tested the endothelium-protective PDE5 inhibitor sildenafil, which reduced apoptosis and improved metabolic activity of endothelial cells in vitro. Accordingly, sildenafil treatment improved survival and reduced target organ damage during experimental SR-aGVHD. Our results demonstrate extensive damage, structural changes, and dysfunction of the vasculature during aGVHD. Therapeutic intervention by endothelium-protecting agents is an attractive approach for SR-aGVHD complementing current anti-inflammatory treatment options.

Apixaban Downregulates Endothelial Inflammatory and Prothrombotic Phenotype in an In Vitro Model of Endothelial Dysfunction in Uremia.

PURPOSE: Chronic kidney disease (CKD) associates with inflammatory and prothrombotic phenotypes, resulting in higher cardiovascular risk. Factor Xa displays functions beyond coagulation, exhibiting proinflammatory effects. The aim of the present study was to investigate whether a direct FXa inhibitor protects from the endothelial dysfunction (ED) caused by uremia. METHODS: Macro (HUVEC) and microvascular (HMEC) endothelial cells (ECs) were exposed to serum from uremic patients or healthy donors, in absence and presence of apixaban (60 ng/ml). We evaluated changes in surface VCAM-1 and ICAM-1, intracellular eNOS, reactive oxygen species (ROS), and von Willebrand Factor (VWF) production by immunofluorescence, reactivity of the extracellular matrix (ECM) towards platelets, and intracellular signaling. RESULTS: ECs exposed to uremic serum triggered dysregulation of all the parameters. Presence of apixaban resulted in decreased expression of VCAM-1 (178 ± 14 to 89 ± 2% on HMEC and 324 ± 71 to 142 ± 25% on HUVEC) and ICAM-1 (388 ± 60 to 111 ± 10% on HMEC and 148 ± 9% to 90 ± 7% on HUVEC); increased eNOS (72 ± 8% to 95 ± 10% on HMEC); normalization of ROS levels (173 ± 21 to 114 ± 13% on HMEC and 165 ± 14 to 127 ± 7% on HUVEC); lower production of VWF (168 ± 14 to 92 ± 4% on HMEC and 151 ± 22 to 99 ± 11% on HUVEC); and decreased platelet adhesion onto ECM (134 ± 22 to 93 ± 23% on HMEC and 161 ± 14 to 117 ± 7% on HUVEC). Apixaban inhibited p38MAPK and p42/44 activation in HUVEC (139 ± 15 to 48 ± 15% and 411 ± 66 to 177 ± 57%, respectively) (p < 0.05 vs control for all parameters). CONCLUSION: Anti-FXa strategies, such as apixaban, prevented ED caused by the uremic milieu, exhibiting anti-inflammatory and antioxidant properties and modulating the reactivity of the ECM.

Successful management of three patients with autoimmune thrombotic thrombocytopenic purpura with paradigm-changing therapy: Caplacizumab, steroids, plasma exchange, rituximab, and intravenous immunoglobulins (CASPERI).

Autoimmune thrombotic thrombocytopenic purpura (aTTP) is a severe disease caused by the production of autoantibodies against von Willebrand factor (vWF)-cleaving ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin-1 motifs; 13th member of the family). In 2018, caplacizumab was approved for the treatment of patients with acute aTTP in conjunction with plasma exchange (PE) and immunosuppressive therapy. Immunosuppressive standard of care includes mainly steroids whereas rituximab is usually reserved for refractory cases. We report three patients with a first acute episode of aTTP who were successfully treated with a paradigm-changing scheme including standard of care (caplacizumab, steroids and PE) plus upfront therapy with rituximab and intravenous immunoglobulins (CASPERI). Rituximab was added 1-4 days after diagnosis, when ADAMTS13 autoantibodies were detected and intravenous immunoglobulins were administered after performing PE using albumin as replacement solution. Successful outcome was observed in all three patients: platelet recovery (>150 × 109/L) was observed after 3, 4, and 5 days from diagnosis; ADAMTS13 activity >5% and ADAMTS13 autoantibodies were negative after 14, 15, and 21 days from diagnosis. In conclusion, caplacizumab, steroids, PE (using fresh frozen plasma or albumin as replacement solution and adding intravenous immunoglobulins) plus upfront rituximab therapy was a safe and efficient combination to induce remission in case of acute aTTP.

Defibrotide inhibits donor leucocyte-endothelial interactions and protects against acute graft-versus-host disease.

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is an effective therapy for the treatment of high-risk haematological malignant disorders and other life-threatening haematological and genetic diseases. Acute graft-versus-host disease (aGvHD) remains the most frequent cause of non-relapse mortality following allo-HCT and limits its extensive clinical application. Current pharmacologic agents used for prophylaxis and treatment of aGvHD are not uniformly successful and have serious secondary side effects. Therefore, more effective and safe prophylaxis and therapy for aGvHD are an unmet clinical need. Defibrotide is a multi-target drug successfully employed for prophylaxis and treatment of veno-occlusive disease/sinusoidal obstruction syndrome. Recent preliminary clinical data have suggested some efficacy of defibrotide in the prevention of aGvHD after allo-HCT. Using a fully MHC-mismatched murine model of allo-HCT, we report here that defibrotide, either in prophylaxis or treatment, is effective in preventing T cell and neutrophil infiltration and aGvHD-associated tissue injury, thus reducing aGvHD incidence and severity, with significantly improved survival after allo-HCT. Moreover, we performed in vitro mechanistic studies using human cells revealing that defibrotide inhibits leucocyte-endothelial interactions by down-regulating expression of key endothelial adhesion molecules involved in leucocyte trafficking. Together, these findings provide evidence that defibrotide may represent an effective and safe clinical alternative for both prophylaxis and treatment of aGvHD after allo-HCT, paving the way for new therapeutic approaches.

Up-regulation of HDACs, a harbinger of uraemic endothelial dysfunction, is prevented by defibrotide.

Endothelial dysfunction is an earlier contributor to the development of atherosclerosis in chronic kidney disease (CKD), in which the role of epigenetic triggers cannot be ruled out. Endothelial protective strategies, such as defibrotide (DF), may be useful in this scenario. We evaluated changes induced by CKD on endothelial cell proteome and explored the effect of DF and the mechanisms involved. Human umbilical cord vein endothelial cells were exposed to sera from healthy donors (n = 20) and patients with end-stage renal disease on haemodialysis (n = 20). Differential protein expression was investigated by using a proteomic approach, Western blot and immunofluorescence. HDAC1 and HDAC2 overexpression was detected. Increased HDAC1 expression occurred at both cytoplasm and nucleus. These effects were dose-dependently inhibited by DF. Both the HDACs inhibitor trichostatin A and DF prevented the up-regulation of the endothelial dysfunction markers induced by the uraemic milieu: intercellular adhesion molecule-1, surface Toll-like receptor-4, von Willebrand Factor and reactive oxygen species. Moreover, DF down-regulated HDACs expression through the PI3/AKT signalling pathway. HDACs appear as key modulators of the CKD-induced endothelial dysfunction as specific blockade by trichostatin A or by DF prevents endothelial dysfunction responses to the CKD insult. Moreover, DF exerts its endothelial protective effect by inhibiting HDAC up-regulation likely through PI3K/AKT.

Lithium Augmentation Versus Citalopram Combination in Imipramine-Resistant Major Depression: A 10-Week Randomized Open-Label Study.

PURPOSE/BACKGROUND: According to available international clinical guides, tricyclic antidepressants are our first- or second-line treatment of choice for severe unipolar major depression. However, the therapeutic option after an unsuccessful response to a tricyclic antidepressant drug in unipolar major depression is still unclear. METHODS/PROCEDURES: This 10-week randomized open-label study assessed the effectiveness of add-on lithium (adjusted to plasma levels) compared with add-on citalopram (30 mg/d) in 104 severe unipolar major depressive patients after a 10-week unsuccessful imipramine (adjusted to plasma level). Efficacy analyses examined changes in the severity of depression symptoms from baseline visit to endpoint and the comparative remission rate between treatment subgroups. FINDINGS/RESULTS: The randomized sample consisted of 104 imipramine-resistant severe unipolar major depressed patients. Both, the percentage of remitters (40.4% vs 21.1%, P = 0.034) and the mean reduction of the Hamilton Depression Rating Scale score (58.8% vs 42.5%, P = 0.005) were significantly greater in the add-on citalopram subgroup at endpoint visit. IMPLICATIONS/CONCLUSIONS: Although we should be cautious about generalizing these results to patients with a less severe unipolar major episode, results from the present study suggest that add-on citalopram is a very effective treatment option in unipolar major depressive episodes after an unsuccessful imipramine regimen.

Switching to Imipramine Versus Add-on Mirtazapine in Venlafaxine-Resistant Major Depression: A 10-Week Randomized Open Study.

PURPOSE/BACKGROUND: Newer-generation antidepressants used in monotherapy or in combination with other newer-generation antidepressants or other psychotropic drugs are usually preferred as first- or second-step treatment options in resistant depression. According to our clinical experience, tricyclic antidepressants still are one of our preferred first choices in treatment-resistant moderate to severe unipolar major depressive episodes. METHODS: This 10-week open-design randomized study assessed the effectiveness of switching to imipramine (adjusted to plasma levels) compared with add-on mirtazapine (30 mg/d) for treatment of moderate to severe unipolar major depressive episodes after a 10-week unsuccessful venlafaxine regimen (225-300 mg/d). Efficacy analyses examined the change in depressive symptoms severity from baseline visit to endpoint and the comparative remission rate between treatment subgroups. FINDINGS/RESULTS: The randomized sample consisted of 112 venlafaxine-resistant moderate to severe unipolar major depressed patients. Both the percentage of remitters (71.43% vs 39.28%) and the mean reduction of the Hamilton Depression Rating Scale score (76.94% vs 50.72%) were significantly larger in the imipramine subgroup. IMPLICATIONS/CONCLUSIONS: Even though we should be cautious about generalizing these results to patients with a less severe unipolar major episodes, our study suggest that switching to imipramine is a very effective treatment option in unipolar major depressive episodes after an unsuccessful venlafaxine regimen.

Idarucizumab, but not procoagulant concentrates, fully restores dabigatran-altered platelet and fibrin components of hemostasis.

BACKGROUND: Comparative studies on the restoration of hemostasis with different reversal agents after dabigatran therapy have not been performed. We compared the efficacy and prothrombotic potential of the specific antidote idarucizumab with that of previously recommended non-specific procoagulant concentrates. STUDY DESIGN AND METHODS: We explored the in vitro effects of dabigatran (184 ng/mL) on fibrin and platelet-aggregate formation onto a damaged vessel under flow conditions (600 s-1 ). The reversal mechanisms and efficacy of idarucizumab (0.3-3 mg/mL) were compared with that of the non-specific procoagulant concentrates aPCC (25-75 U/Kg), PCC (70 U/Kg), or rFVIIa (120 µg/Kg). Generation of thrombin and prothrombin fragment (F1 + 2), and thromboelastometry parameters of clot formation were measured. RESULTS: Dabigatran caused pronounced reductions in fibrin (87%) and platelet interactions (36%) with damaged vessels (p < 0.01) and significantly impaired thrombin generation and thromboelastometric parameters (delayed dynamics and reduced firmness). Idarucizumab completely normalized rates of fibrin and platelet coverage to baseline values in flow studies; and reversed the alterations in thrombin generation, F1 + 2 and thromboelastometry parameters produced by dabigatran. In comparison, aPCC and PCC only partially compensated for the dabigatran-induced alterations in fibrin deposition, but were unable to fully restore them to baseline values. Reversal with aPCC or PCC improved the majority of alterations in coagulation-related tests, but tended to overcompensate thrombin generation kinetics and significantly increased F1 + 2 levels. CONCLUSION: Idarucizumab antagonizes alterations of direct and indirect biomarkers of hemostasis caused by dabigatran. In our studies, idarucizumab was clearly more efficacious than strategies with non-specific procoagulant concentrates and devoid of the excessive procoagulant tendency observed with the latter.

Antioxidant and Anti-Inflammatory Strategies Based on the Potentiation of Glutathione Peroxidase Activity Prevent Endothelial Dysfunction in Chronic Kidney Disease.

BACKGROUND/AIMS: Accelerated atherosclerosis in chronic kidney disease (CKD) is preceded by endothelial dysfunction (ED), which exhibits a proinflammatory and prothrombotic phenotype and enhanced oxidative stress. In this study, the effect of several compounds with anti-inflammatory and/or antioxidant properties on uremia-induced endothelial dysfunction has been evaluated in an in vitro model. METHODS: Endothelial cells (ECs) were exposed to sera from uremic patients in the absence and presence of the flavonoids apigenin, genistein and quercetin, the antioxidant enzyme mimetics (AEM) ebselen (glutathione peroxidase mimetic), EUK-134 and EUK-118 (both superoxide dismutase mimetics), and the pharmacological drug N-acetylcysteine (NAC). We explored changes in the expression of adhesion receptors on the cell surface, by immunofluorescence, the production of radical oxygen species (ROS), by fluorescence detection, and the activation of signaling proteins related to inflammation, by both a phosphospecific antibody cell-based ELISA and immunoblotting techniques. RESULTS: Uremic media induced a significantly increased expression of ICAM-1, overproduction of radical oxygen species (ROS) and activation of p38 mitogen activated protein kinase (p38MAPK) and Nuclear Factor kB (NFkB) in ECs. Quercetin, the AEM and NAC showed a significant inhibitory effect on both ICAM-1 expression and ROS generation (p<0.05). All the compounds reduced p38MAPK activation, but only the AEM, especially ebselen, and NAC, both potentiating the glutathione peroxidase pathway, also inhibited NFkB activation. These two compounds were capable of increasing endothelial glutathione levels, especially in response to uremia. CONCLUSION: Our results indicate that the potentiation of the antioxidant pathways can be an effective strategy to improve endothelial dysfunction in uremia and a potential target to reduce the cardiovascular risk in this population.

What is going on between defibrotide and endothelial cells? Snapshots reveal the hot spots of their romance.

Defibrotide (DF) has received European Medicines Agency authorization to treat sinusoidal obstruction syndrome, an early complication after hematopoietic cell transplantation. DF has a recognized role as an endothelial protective agent, although its precise mechanism of action remains to be elucidated. The aim of the present study was to investigate the interaction of DF with endothelial cells (ECs). A human hepatic EC line was exposed to different DF concentrations, previously labeled. Using inhibitory assays and flow cytometry techniques along with confocal microscopy, we explored: DF-EC interaction, endocytic pathways, and internalization kinetics. Moreover, we evaluated the potential role of adenosine receptors in DF-EC interaction and if DF effects on endothelium were dependent of its internalization. Confocal microscopy showed interaction of DF with EC membranes followed by internalization, though DF did not reach the cell nucleus even after 24 hours. Flow cytometry revealed concentration, temperature, and time dependent uptake of DF in 2 EC models but not in other cell types. Moreover, inhibitory assays indicated that entrance of DF into ECs occurs primarily through macropinocytosis. Our experimental approach did not show any evidence of the involvement of adenosine receptors in DF-EC interaction. The antiinflammatory and antioxidant properties of DF seem to be caused by the interaction of the drug with the cell membrane. Our findings contribute to a better understanding of the precise mechanisms of action of DF as a therapeutic and potential preventive agent on the endothelial damage underlying different pathologic situations.

Translational evidence of prothrombotic and inflammatory endothelial damage in Cushing syndrome after remission.

OBJECTIVE: Sustained evidence from observational studies indicates that after remission of Cushing syndrome (CS) a cardiovascular risk phenotype persists. Here, we performed a translational study in active CS and CS in remission (RCS) to evaluate the subclinical cardiometabolic burden and to explore the direct pro-inflammatory and prothrombotic potential of their sera on the endothelium in an in vitro translational atherothrombotic cell model. PATIENTS: Cross sectional study. The groups were (n = 9/group): I. RCS; II. Active CS (ACS) and III. Controls (CTR), all matched for age, body mass index, sex, without other hormonal deficits. DESIGN: We evaluated in vivo: cardiometabolic profile; endothelial markers (sVCAM-1, NO); endothelial dysfunction (FMD); intima-media thickness and body composition (DEXA). In vitro endothelial cells (EC) were exposed to sera taken from the different subjects to evaluate inflammatory EC response (tisVCAM) and thrombogenicity of the generated extracellular matrix (ECM): von Willebrand factor (VWF) and platelet reactivity. RESULTS: Three of the 9 RCS subjects were on glucocorticoid replacement therapy (GC-RT). Patients on GC-RT had a shorter period of time in stable remission. In vivo analysis ACS showed typically metabolic features, while cardiometabolic markers reached statistical significance for RCS only for Hs-CRP (P < .01). In vitro:EC exposed to ACS and RCS sera displayed increased tisVCAM-1 (P < .01 for ACS and P < .05 for RCS vs CTR), VWF (P < .01 for ACS and P < .05 for RCS vs CTR) and platelet adhesion on ECM (P < .01 for ACC and P < .05 for RCS vs CTR). No statistically significant differences were observed between GC-RT RSC and RCS without GC-RT. CONCLUSIONS: The sera of premenopausal women with CS in remission, without atherothrombotic disease, contain circulatory endothelial deleterious factors with a direct thrombogenic and pro-inflammatory endothelial effect that could increase cardiovascular risk.

Internalization of Tissue Factor-Rich Microvesicles by Platelets Occurs Independently of GPIIb-IIIa, and Involves CD36 Receptor, Serotonin Transporter and Cytoskeletal Assembly.

Platelets are important in hemostasis, but also detect particles and pathogens in the circulation. Phagocytic and endocytic activities of platelets are widely recognized; however, receptors and mechanisms involved remain poorly understood. We previously demonstrated that platelets internalize and store phospholipid microvesicles enriched in human tissue factor (TF+MVs) and that platelet-associated TF enhances thrombus formation at sites of vascular damage. Here, we investigate the mechanisms implied in the interactions of TF+MVs with platelets and the effects of specific inhibitory strategies. Aggregometry and electron microscopy were used to assess platelet activation and TF+MVs uptake. Cytoskeletal assembly and activation of phosphoinositide 3-kinase (PI3K) and RhoA were analyzed by western blot and ELISA. Exposure of platelets to TF+MVs caused reversible platelet aggregation, actin polymerization and association of contractile proteins to the cytoskeleton being maximal at 1 min. The same kinetics were observed for activation of PI3K and translocation of RhoA to the cytoskeleton. Inhibitory strategies to block glycoprotein IIb-IIIa (GPIIb-IIIa), scavenger receptor CD36, serotonin transporter (SERT) and PI3K, fully prevented platelet aggregation by TF+MVs. Ultrastructural techniques revealed that uptake of TF+MVs was efficiently prevented by anti-CD36 and SERT inhibitor, but only moderately interfered by GPIIb-IIIa blockade. We conclude that internalization of TF+MVs by platelets occurs independently of receptors related to their main hemostatic function (GPIIb-IIIa), involves the scavenger receptor CD36, SERT and engages PI3-Kinase activation and cytoskeletal assembly. CD36 and SERT appear as potential therapeutic targets to interfere with the association of TF+MVs with platelets and possibly downregulate their prothrombotic phenotype.

In vitro evaluation of the hemostatic effectiveness of cryopreserved platelets.

BACKGROUND: Cryopreserved platelet (CPP) concentrates exhibit a variety of morphologic and functional alterations that may affect the action of CPP with accelerated platelet (PLT) response and clotting. The objective of this study was to compare the in vitro hemostatic effect of CPP with fresh whole blood (WB) and standard 5-day PLT concentrates (PCs). STUDY DESIGN AND METHODS: WB collected from eight healthy donors was used to prepare fresh WB, PLT-depleted WB (TPN), and PLT-restored TPN using CPP (TPN-CPP) or PC (TPN-PC). Clot properties were evaluated with thromboelastometry (ROTEM); adhesion and aggregate formation under high shear (Impact-R); and PLT adhesion, aggregate formation, fibrin formation, and prothrombin activation under medium shear in a perfusion system. RESULTS: TPN-CPP had faster clot initiation (ROTEM clot time--TPN-CPP 115 sec, WB 194 sec, TPN-PC 161 sec), and CPP contributes to a strong clot with PLT involvement (maximum clot firmness--TPN-CPP 32 mm, WB 62 mm, TPN-PC 59 mm). The Impact-R PLT-covered area with TPN-CPP was less than those of WB and PCs, but aggregate size was the same as WB. PLT coverage in perfusion studies was observed with TPN-CPP, although generally less than both WB and PC. Fibrin was deposited with CPP-restored samples, but did not exceed the level of WB. CONCLUSION: CPPs present a phenotype supporting a moderate increase in the rate of clot formation, form stable PLT clots, and do not present a hypercoagulable phenotype during in vitro functional tests.