Barcelona Endothelium Team (BET)

  • Carreras group
Campus Clinic-UB

Primary Hemostasis Laboratory
Hemotherapy-Hemostasis Department
3rd Floor, 3rd Staircase
Hospital Clinic de Barcelona
Villarroel, 170
08036 Barcelona

 www.betresearch.org

Ext Phone (2034)

Summary

The Barcelona Endothelium Team (BET) is a research group that has dedicated many years to the study of the endothelium and endothelial damage in various pathologies. One of our most productive lines is devoted to the characterization of endothelial damage in the context of both autologous and allogeneic hematopoietic stem cell transplantation (HSCT). In this framework, we are deepening our knowlege of the mechanisms involved in endothelial dysfunction, the role of the endothelium in the development of some complications observed after HSCT, and the search of pharmaceutical agents that could protect the endothelia and consequently prevent these complications.

Research

The main objectives of BET group in the HSCT framework are:

  •  To characterize the endothelial damage produced because of the allo-reactivity phenomena occurring after allogeneic HSCT.
  • To elucidate which are the agents producing the endothelial damage observed during allogeneic HSCT.
  • To analyze the role of the endothelial damage in the development of some complications observed early after HSCT as veno-occlusive disease of the liver, capillary leak syndrome, thrombotic microangiopathy, engraftment syndrome, diffuse alveolar hemorrhage, and acute graft versus-host disease.
  • To investigate which agents can protect the endothelia during HSCT and consequently prevent these complications.

Collaborations

Dr. Ginés Escolar, Hospital Clínic de Barcelona, Universitat de Barcelona, Spain
Dra. Montserrat Rovira. SCT Unit. Hospital Clinic, Barcelona, Universitat de Barcelona, Spain
Prof. Dr. Ernst Holler, University Medical Centre, University of Regensburg, Germany
Prof. Dr. Günter Eissner, University College Dublin, Ireland
Jazz Pharmaceuticals Inc

People

NamePosition
Enric CarrerasE.CarrerasPrincipal Investigator
Maribel Díaz-RicartDiaz-Ricart SPrincipal Investigator
Enrique MirEnrique MirPhD Student
Marta PalomoMarta PalomoPostdoctoral Investigator

Selected publications

Palomo M, Mir E, Rovira M, Escolar G, Carreras E, Diaz-Ricart M

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

Blood 11 Jan 2016, . Epub 11 Jan 2016
Defibrotide (DF) has received EMA 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 endothelial cell line was exposed to different DF concentrations, previously labelled. 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 cell nucleus even after 24h. Flow cytometry revealed concentration, temperature and time dependent up-take of DF in two 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 anti-inflammatory and antioxidant properties of DF seem to be due to 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 pathological situations.
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Carreras E

How I manage sinusoidal obstruction syndrome after haematopoietic cell transplantation.

Br. J. Haematol. Feb 2015, 168 (4) 481-91. Epub 17 Nov 2014
Sinusoidal obstruction syndrome (SOS), also called veno-occlusive disease of the liver, is one of the most relevant complications of endothelial origin that appears early after haematopoietic cell transplantation (HCT). Despite its relatively low incidence and the fact that most cases of SOS resolve spontaneously, the cases that evolve to multi-organ failure (MOF; severe SOS) have a mortality rate higher than 80% and represent one of the major clinical problems after HCT. For this reason, transplantation teams must have a pre-established policy regarding preventive measures in high-risk patients, strict daily control of weight and fluid balance during HCT, homogeneous diagnostic criteria, appropriate complementary studies for a correct differential diagnosis and measures to prevent and manage hepatorenal syndrome; in addition they must also be ready to start early treatment with defibrotide in patients with a possible severe SOS. Due to the lack of definitive evidence to enable the establishment of general recommendations in the management of SOS, this review analyses all of these aspects based on the author's personal experience.
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Carmona A, Díaz-Ricart M, Palomo M, Molina P, Pino M, Rovira M, Escolar G, Carreras E

Distinct deleterious effects of cyclosporine and tacrolimus and combined tacrolimus-sirolimus on endothelial cells: protective effect of defibrotide.

Biol. Blood Marrow Transplant. Oct 2013, 19 (10) 1439-45. Epub 9 Jul 2013
Endothelial dysfunction seems to be a key factor in the development of several complications observed early after hematopoietic stem cell transplantation (HSCT). The conditioning regimen and many other factors associated with the procedure are responsible for this endothelial damage. The effects of immunosuppressive agents on endothelial function have not been explored in detail. We evaluated the effects of 3 drugs commonly used in HSCT: 2 calcineurin inhibitors, cyclosporine A (CSA) and tacrolimus (TAC), and an inhibitor of mTOR, sirolimus (SIR). We also evaluated the effect of the combination of TAC and SIR (TAC+SIR), which is used increasingly in clinical practice. Microvascular endothelial cells (HMEC-1) were exposed to these drugs to evaluate changes in (1) intercellular adhesion molecule (ICAM)-1 expression on the cell surface, assessed by immunofluorescence labeling and expressed as the mean gray value (MGV); (2) reactivity of the extracellular matrix (ECM) toward platelets, upon exposure of the ECM to circulating blood; and (3) whole-blood clot formation, assessed by thromboelastometry. Studies were conducted in the absence and presence of defibrotide (DF) to assess its possible protective effect. The exposure of HMEC-1 to CSA and TAC+SIR significantly increased the expression of ICAM-1 (157.5 ± 11.6 and 153.4 ± 9.5 MGV, respectively, versus 105.7 ± 6.5 MGV in controls [both P < .05]). TAC applied alone increased ICAM-1 slightly (120.3 ± 8.2 MGV), and SIR had no effect (108.9 ± 7.4 MGV). ECM reactivity increased significantly only in response to CSA (surface covered by platelets of 41.2% ± 5.4% versus 30.1% ± 2.0%, P < .05). DF attenuated all these changes. No significant changes in the viscoelastic properties of clot formation were observed in any condition with blood samples incubated in vitro. In conclusion, CSA and TAC+SIR had a proinflammatory effect, but only CSA exhibited an additional prothrombotic effect. Interestingly, DF exerted clear protective anti-inflammatory and antithrombotic effects on the endothelium.
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Carreras E, Diaz-Ricart M

The role of the endothelium in the short-term complications of hematopoietic SCT.

Bone Marrow Transplant. Dec 2011, 46 (12) 1495-502. Epub 4 Apr 2011
In this review, we analyse the role of the endothelium in the development of several complications that appear soon after haematopoietic SCT (HSCT). Once it had been demonstrated that sinusoidal damage is the initiating event of the sinusoidal obstruction syndrome, it was considered that other short-term complications with overlapping clinical manifestations, such as capillary leak syndrome, engraftment syndrome, transplant-associated microangiopathy, diffuse alveolar haemorrhage and idiopathic pneumonia syndrome, could have an endothelial origin. During HSCT, endothelial cells (ECs) are activated and damaged by several factors, including conditioning, cytokines released by damaged tissues, endotoxins translocated through damaged mucosa, drugs used in the procedure, the engraftment, and--in the allogeneic setting--immunological reactions. The different clinical syndromes that occur could be determined by the predominant phenotypic change in the ECs and the location of this change (organ dependant or systemic). Several translational studies have provided evidence of this endothelial dysfunction on the basis of analysis of soluble markers, soluble forms of adhesion molecules, the enumeration of circulating ECs and microparticles, and morphologic and functional changes induced in cultured ECs. This increased knowledge has opened up a wide range of potential pharmacologic interventions to prevent or treat endothelial damage and, consequently, to improve the outcome of patients receiving HSCT.
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Palomo M, Diaz-Ricart M, Rovira M, Escolar G, Carreras E

Defibrotide prevents the activation of macrovascular and microvascular endothelia caused by soluble factors released to blood by autologous hematopoietic stem cell transplantation.

Biol. Blood Marrow Transplant. Apr 2011, 17 (4) 497-506. Epub 30 Nov 2010
Endothelial activation and damage occur in association with autologous hematopoietic stem cell transplantation (HSCT). Several of the early complications associated with HSCT seem to have a microvascular location. Through the present study, we have characterized the activation and damage of endothelial cells of both macro (HUVEC) and microvascular (HMEC) origin, occurring early after autologous HSCT, and the potential protective effect of defibrotide (DF). Sera samples from patients were collected before conditioning (Pre), at the time of transplantation (day 0), and at days 7, 14, and 21 after autologous HSCT. Changes in the expression of endothelial cell receptors at the surface, presence and reactivity of extracellular adhesive proteins, and the signaling pathways involved were analyzed. The expression of ICAM-1 at the cell surface increased progressively in both HUVEC and HMEC. However, a more prothrombotic profile was denoted for HMEC, in particular at the time of transplantation (day 0), reflecting the deleterious effect of the conditioning treatment on the endothelium, especially at a microvascular location. Interestingly, this observation correlated with a higher increase in the expression of both tissue factor and von Willebrand factor on the extracellular matrix, together with activation of intracellular p38 MAPK and Akt. Previous exposure and continuous incubation of cells with DF prevented the signs of activation and damage induced by the autologous sera. These observations corroborate that conditioning treatment in autologous HSCT induces a proinflammatory and a prothrombotic phenotype, especially at a microvascular location, and indicate that DF has protective antiinflammatory and antithrombotic effects in this setting.
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Current projects

Deepening the knowledge of Defibrotide.

Project leader:Enric Carreras
Funding:
Start date:01/10/2010
End date:31/12/2016

Previous projects

Disfunción endotelial en el trasplante de progenitores hematopoyéticos: caracterización biológica y papel en las principales complicaciones precoces pos-trasplante

Project leader:Enric Carreras
Code:FIS PI050153
Funding:
Start date:23/07/2005
End date:31/12/2008

Disfunción endotelial post-trasplante hematopoyético. Impacto de los agentes empleados en el régimen de acondicionamiento y análisis de posibles agentes protectores.

Project leader:Enric Carreras
Code:FIS PI000156
Funding:
Start date:01/01/2008
End date:31/12/2011

Characterization of endothelial dysfunction that develops in haematopoietic stem cell transplantation: role in the main complications appearing early after transplantation

Project leader:Enric Carreras
Funding:
Start date:31/01/2008
End date:31/03/2011