Astrocytes are necessary for blood-brain barrier maintenance in the adult mouse brain.

In the adult brain, multiple cell types are known to produce factors that regulate blood-brain barrier (BBB) properties, including astrocytes. Yet several recent studies disputed a role for mature astrocytes at the BBB. To determine if astrocytes contribute a nonredundant and necessary function in maintaining the adult BBB, we used a mouse model of tamoxifen-inducible astrocyte ablation. In adult mice, tamoxifen induction caused sparse apoptotic astrocyte cell death within 2 hr. Indicative of BBB damage, leakage of the small molecule Cadaverine, and the large plasma protein fibrinogen into the brain parenchyma indicative of BBB damage was detected as early as astrocyte ablation was present. Vessels within and close to regions of astrocyte loss had lower expression of the tight junction protein zonula occludens-1 while endothelial glucose transporter 1 expression was undisturbed. Cadaverine leakage persisted for several weeks suggesting a lack of barrier repair. This is consistent with the finding that ablated astrocytes were not replaced. Adjacent astrocytes responded with partial nonproliferative astrogliosis, characterized by morphological changes and delayed phosphorylation of STAT3, which restricted dye leakage to the brain and vessel surface areas lacking coverage by astrocytes 1 month after ablation. In conclusion, astrocytes are necessary to maintain BBB integrity in the adult brain. BBB-regulating factors secreted by other cell types, such as pericytes, are not sufficient to compensate for astrocyte loss.

Endocytosis of the glutamate transporter 1 is regulated by laforin and malin: Implications in Lafora disease.

Lafora disease (LD) is a fatal rare type of progressive myoclonus epilepsy that appears during early adolescence. The disease is caused by mutations in EPM2A or EPM2B genes, which encode laforin, a glucan phosphatase, and malin, an E3-ubiquitin ligase, respectively. Although the exact roles of laforin and malin are still not well understood, it is known that they work as a complex in which laforin recruits targets that will be ubiquitinated by malin. Recently, we suggested that the type of epilepsy that accompanies LD could be due to deficiencies in the function of the astrocytic glutamate transporter GLT-1. We described that astrocytes from LD mouse models presented decreased levels of GLT-1 at the plasma membrane, leading to increased levels of glutamate in the brain parenchyma. In this work, we present evidence indicating that in the absence of a functional laforin/malin complex (as in LD cellular models) there is an alteration in the ubiquitination of GLT-1, which could be the cause of the reduction in the levels of GLT-1 at the plasma membrane. On the contrary, overexpression of the laforin/malin complex promotes the retention of GLT-1 at the plasma membrane. This retention may be due to the direct ubiquitination of GLT-1 and/or to an opposite effect of this complex on the dynamics of the Nedd4.2-mediated endocytosis of the transporter. This work, therefore, presents new pieces of evidence on the regulation of GLT-1 by the laforin/malin complex, highlighting its value as a therapeutic target for the amelioration of the type of epilepsy that accompanies LD.

Repetitive Diffuse Mild Traumatic Brain Injury Causes an Atypical Astrocyte Response and Spontaneous Recurrent Seizures.

Focal traumatic brain injury (TBI) induces astrogliosis, a process essential to protecting uninjured brain areas from secondary damage. However, astrogliosis can cause loss of astrocyte homeostatic functions and possibly contributes to comorbidities such as posttraumatic epilepsy (PTE). Scar-forming astrocytes seal focal injuries off from healthy brain tissue. It is these glial scars that are associated with epilepsy originating in the cerebral cortex and hippocampus. However, the vast majority of human TBIs also present with diffuse brain injury caused by acceleration-deceleration forces leading to tissue shearing. The resulting diffuse tissue damage may be intrinsically different from focal lesions that would trigger glial scar formation. Here, we used mice of both sexes in a model of repetitive mild/concussive closed-head TBI, which only induced diffuse injury, to test the hypothesis that astrocytes respond uniquely to diffuse TBI and that diffuse TBI is sufficient to cause PTE. Astrocytes did not form scars and classic astrogliosis characterized by upregulation of glial fibrillary acidic protein was limited. Surprisingly, an unrelated population of atypical reactive astrocytes was characterized by the lack of glial fibrillary acidic protein expression, rapid and sustained downregulation of homeostatic proteins and impaired astrocyte coupling. After a latency period, a subset of mice developed spontaneous recurrent seizures reminiscent of PTE in human TBI patients. Seizing mice had larger areas of atypical astrocytes compared with nonseizing mice, suggesting that these atypical astrocytes might contribute to epileptogenesis after diffuse TBI.SIGNIFICANCE STATEMENT Traumatic brain injury (TBI) is a leading cause of acquired epilepsies. Reactive astrocytes have long been associated with seizures and epilepsy in patients, particularly after focal/lesional brain injury. However, most TBIs also include nonfocal, diffuse injuries. Here, we showed that repetitive diffuse TBI is sufficient for the development of spontaneous recurrent seizures in a subset of mice. We identified an atypical response of astrocytes induced by diffuse TBI characterized by the rapid loss of homeostatic proteins and lack of astrocyte coupling while reactive astrocyte markers or glial scar formation was absent. Areas with atypical astrocytes were larger in animals that later developed seizures suggesting that this response may be one root cause of epileptogenesis after diffuse TBI.

Homeostasis of the astrocytic glutamate transporter GLT-1 is altered in mouse models of Lafora disease.

Lafora disease (LD, OMIM 254780) is a fatal rare disorder characterized by epilepsy and neurodegeneration. Although in recent years a lot of information has been gained on the molecular basis of the neurodegeneration that accompanies LD, the molecular basis of epilepsy is poorly understood. Here, we present evidence indicating that the homeostasis of glutamate transporter GLT-1 (EAAT2) is compromised in mouse models of LD. Our results indicate that primary astrocytes from LD mice have reduced capacity of glutamate transport, probably because they present a reduction in the levels of the glutamate transporter at the plasma membrane. On the other hand, the overexpression in cellular models of laforin and malin, the two proteins related to LD, results in an accumulation of GLT-1 (EAAT2) at the plasma membrane and in a severe reduction of the ubiquitination of the transporter. All these results suggest that the laforin/malin complex slows down the endocytic recycling of the GLT-1 (EAAT2) transporter. Since, defects in the function of this transporter lead to excitotoxicity and epilepsy, we suggest that the epilepsy that accompanies LD could be due, at least in part, to deficiencies in the function of the GLT-1 (EAAT2) transporter.

HE4, Ca125 and ROMA algorithm for differential diagnosis between benign gynaecological diseases and ovarian cancer.

The aim of this study is to evaluate the diagnostic performance of human epididymis protein 4 (HE4), cancer antigen 125 (Ca125) and the risk of ovarian malignancy algorithm (ROMA) in discriminating ovarian cancer from other benign gynaecological diseases. Serum levels of HE4 and Ca125 were measured in 119 women with benign gynaecological diseases, 29 patients with primary ovarian cancer, 32 patients with ovarian cancer on chemotherapy treatment (18 of them with progressive disease), 6 patients treated and free of disease and 32 healthy women. Sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios (LR ±) were calculated. Receiver operator characteristic (ROC) curves were constructed, and the areas under the curve (AUC) were calculated. High serum levels for HE4, Ca125 and ROMA were observed in cancer patients. HE4 was elevated in 12.6 %, Ca125 in 21 % and ROMA in 9.2 % in the benign group, but HE4 was not elevated in endometriosis. The AUC values for HE4, Ca125 and ROMA were 0.92, 0.911 and 0.945 respectively. The sensitivity for discriminating ovarian cancer from benign gynaecological diseases was 86.2 % for HE4 and Ca125 and 93.1 % for ROMA. The specificity was 87.4, 78.9 and 90.7 % for HE4, Ca125 and ROMA. The overall positive likelihood ratio (LR+) was 6.84 for HE4, 4.1 for Ca125 and 10.01 for ROMA. In premenopausal women, LR + was 11.86 for HE4, 5.11 for ROMA and 2.02 for Ca125. HE4 might be significant in the differential diagnosis of ovarian cancer. HE4 seems to be superior to Ca125 in terms of diagnostic performance of all premenopausal women. ROMA could help to discriminate in cases with any doubt with a high diagnostic accuracy.

Ibrutinib followed by ofatumumab consolidation in previously untreated patients with chronic lymphocytic leukemia (CLL): GELLC-7 trial from the Spanish group of CLL (GELLC).

Background: BTK inhibitors have been concurrently administered with anti-CD20 monoclonal antibodies (mAbs) in chronic lymphocytic leukemia (CLL). However, the optimal regimen for combining these two drugs remains pending. Methods: This multi-center phase 2 study aimed to analyze whether consolidation with ofatumumab improved the response in patients with CLL receiving front-line treatment with ibrutinib. Patients received 12 cycles of ibrutinib monotherapy. Those who achieved CR after this induction were maintained on ibrutinib. Conversely, those who did not attain CR continued with ibrutinib in addition to a consolidation, which involved 7 doses of ofatumumab. The primary objective was the complete response (CR) rate at cycle 20. This study is registered within the EU Clinical Trials Register (EudraCT 2016-004937-26). Findings: Between September 8, 2017, and May 21, 2018, 84 patients (median age, 69 years) were included. After completion of 12 cycles of ibrutinib (n = 80), 4 patients (5%) were in CR, 67 (84%) in partial response (PR), and 6 patients (7%) had a PR with lymphocytosis (PRL). After consolidation with ofatumumab, 20 patients improved the response from PR to CR and 6 patients with PRL obtained a PR. Seventy-one patients (85%) completed 20 cycles of treatment, with a CR rate of 24/71 (34%). According to the intention-to-treat analysis at cycle 20, the ORR was 69/84 (82.2%), with a CRR of 24/84 (28.6%). Progression-free survival and overall survival at 48-months were 89.9% (CI: 82.4-95.5) and 92.2% (CI: 85.3-97.1), respectively. Interpretation: These findings underscore the potential for a consolidation strategy in CLL, wherein the addition of a mAb in patients with low tumor burden might enhance the quality of the response. Funding: The study was funded by Janssen that also supplied ibrutinib, whereas ofatumumab was supplied by Novartis.

Astrocyte-mediated mechanisms contribute to traumatic brain injury pathology.

Astrocytes respond to traumatic brain injury (TBI) with changes to their molecular make-up and cell biology, which results in changes in astrocyte function. These changes can be adaptive, initiating repair processes in the brain, or detrimental, causing secondary damage including neuronal death or abnormal neuronal activity. The response of astrocytes to TBI is often-but not always-accompanied by the upregulation of intermediate filaments, including glial fibrillary acidic protein (GFAP) and vimentin. Because GFAP is often upregulated in the context of nervous system disturbance, reactive astrogliosis is sometimes treated as an "all-or-none" process. However, the extent of astrocytes' cellular, molecular, and physiological adjustments is not equal for each TBI type or even for each astrocyte within the same injured brain. Additionally, new research highlights that different neurological injuries and diseases result in entirely distinctive and sometimes divergent astrocyte changes. Thus, extrapolating findings on astrocyte biology from one pathological context to another is problematic. We summarize the current knowledge about astrocyte responses specific to TBI and point out open questions that the field should tackle to better understand how astrocytes shape TBI outcomes. We address the astrocyte response to focal versus diffuse TBI and heterogeneity of reactive astrocytes within the same brain, the role of intermediate filament upregulation, functional changes to astrocyte function including potassium and glutamate homeostasis, blood-brain barrier maintenance and repair, metabolism, and reactive oxygen species detoxification, sex differences, and factors influencing astrocyte proliferation after TBI. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

Mild Traumatic Brain Injury-Induced Disruption of the Blood-Brain Barrier Triggers an Atypical Neuronal Response.

Mild TBI (mTBI), which affects 75% of TBI survivors or more than 50 million people worldwide each year, can lead to consequences including sleep disturbances, cognitive impairment, mood swings, and post-traumatic epilepsy in a subset of patients. To interrupt the progression of these comorbidities, identifying early pathological events is key. Recent studies have shown that microbleeds, caused by mechanical impact, persist for months after mTBI and are correlated to worse mTBI outcomes. However, the impact of mTBI-induced blood-brain barrier damage on neurons is yet to be revealed. We used a well-characterized mouse model of mTBI that presents with frequent and widespread but size-restricted damage to the blood-brain barrier to assess how neurons respond to exposure of blood-borne factors in this pathological context. We used immunohistochemistry and histology to assess the expression of neuronal proteins in excitatory and inhibitory neurons after mTBI. We observed that the expression of NeuN, Parvalbumin, and CamKII was lost within minutes in areas with blood-brain barrier disruption. Yet, the neurons remained alive and could be detected using a fluorescent Nissl staining even 6 months later. A similar phenotype was observed after exposure of neurons to blood-borne factors due to endothelial cell ablation in the absence of a mechanical impact, suggesting that entrance of blood-borne factors into the brain is sufficient to induce the neuronal atypical response. Changes in postsynaptic spines were observed indicative of functional changes. Thus, this study demonstrates That exposure of neurons to blood-borne factors causes a rapid and sustained loss of neuronal proteins and changes in spine morphology in the absence of neurodegeneration, a finding that is likely relevant to many neuropathologies.

Identification of Two Novel EPOR Gene Variants in Primary Familial Polycythemia: Case Report and Literature Review.

Primary familial and congenital polycythemia is a rare disease characterized by an increase in red cell mass that may be due to pathogenic variants in the EPO receptor (EPOR) gene. To date, 33 genetic variants have been reported to be associated. We analyzed the presence of EPOR variants in two patients with polycythemia in whom JAK2 pathogenic variants had been previously discarded. Molecular analysis of the EPOR gene was performed by Sanger sequencing of the coding regions and exon/intron boundaries of exon 8. We performed in vitro culture of erythroid progenitor cells. Segregation studies were done whenever possible. The two patients studied showed hypersensitivity to EPO in in vitro cultures. Analysis of the EPOR gene unveiled two novel pathogenic variants. Genetic testing of asymptomatic relatives could guarantee surveillance and proper management.

Leveraging Zebrafish To Study Bona Fide Astrocytes.

In a recent study, Chen and colleagues demonstrated that zebrafish spinal cord radial glia differentiate into cells that are similar to mammalian astrocytes. This study highlights the validity of the zebrafish model for discovering molecular mechanisms governing astrocyte function.

Potassium and glutamate transport is impaired in scar-forming tumor-associated astrocytes.

Unprovoked recurrent seizures are a serious comorbidity affecting most patients who suffer from glioma, a primary brain tumor composed of malignant glial cells. Cellular mechanisms contributing to the development of recurrent spontaneous seizures include the release of the excitatory neurotransmitter glutamate from glioma into extracellular space. Under physiological conditions, astrocytes express two high affinity glutamate transporters, Glt-1 and Glast, which are responsible for the removal of excess extracellular glutamate. In the context of neurological disease or brain injury, astrocytes become reactive which can negatively affect neuronal function, causing hyperexcitability and/or death. Using electrophysiology, immunohistochemistry, fluorescent in situ hybridization, and Western blot analysis in different orthotopic xenograft and allograft models of human and mouse gliomas, we find that peritumoral astrocytes exhibit astrocyte scar formation characterized by proliferation, cellular hypertrophy, process elongation, and increased GFAP and pSTAT3. Overall, peritumoral reactive astrocytes show a significant reduction in glutamate and potassium uptake, as well as decreased glutamine synthetase activity. A subset of peritumoral astrocytes displayed a depolarized resting membrane potential, further contributing to reduced potassium and glutamate homeostasis. These changes may contribute to the propagation of peritumoral neuronal hyperexcitability and excitotoxic death.

Analysis of the role of intratecal liposomal cytarabine in the prophylaxis and treatment of central nervous system lymphomatosis: The Balearic Lymphoma Group experience.

Central nervous system (CNS) lymphomatosis is a fatal complication of aggressive non-Hodgkin lymphoma (NHL). In lymphoblastic or Burkitt lymphoma, without specific CNS prophylaxis the risk of CNS relapse is 20-30%. DLBCL has a lower risk of relapse (around 5%) but several factors increase its incidence. There is no consensus or trials to conclude which is the best CNS prophylaxis. Best results seem to be associated with the use of intravenous (iv) high-dose methotrexate (HDMTX) but with a significant toxicity. Other options are the administration of intrathecal (IT) MTX, cytarabine or liposomal cytarabine (ITLC). Our aim is to analyze the experience of the centers of the Balearic Lymphoma Group (BLG) about the toxicity and efficacy of ITLC in the prophylaxis and therapy of CNS lymphomatosis. We retrospectively reviewed cases from 2005 to 2015 (n = 58) treated with ITLC. Our toxicity results were: 33% headache, 20% neurological deficits, 11% nausea, 9% dizziness, 4% vomiting, 4% fever, 2% transient blindness and 2% photophobia. In the prophylactic cohort (n = 26) with a median follow-up of 55 months (17-81) only 3 CNS relapses (11%) were observed (testicular DLBCL, Burkitt and plasmablastic lymphoma, with a cumulative incidence of 8%, 14% and 20% respectively). In the treatment cohort (n = 32), CSF complete clearance was obtained in 77% cases. Median OS was 6 months (0-16). Death causes were lymphoma progression (19 patients, 79%), treatment toxicity (2 patients) and non-related (3 patients, 12%). Toxicity profile was good especially when concomitant dexamethasone was administered. In the prophylactic cohort the incidence of CNS relapse in DLBCL group was similar to previously reported for HDMTX and much better than IT MTX. A high number of ITLC injections was associated with better rates of CSF clearance, clinical responses, PFS and lower relapses. Survival is still poor in CNS lymphomatosis and new therapeutic approaches are still needed.

Increased circulating endothelial cells and microparticles in patients with psoriasis.

INTRODUCTION: Psoriasis is a chronic pathology characterized by increased inflammation that can be associated with changes in the vascular endothelium. We quantified the levels of circulating endothelial cells (CECs) and microparticles (MPs) in patients with psoriasis in order to analyze their relationship with endothelial and inflammation markers, subclinical atherosclerosis and microcirculation. METHODS: We studied 20 patients and 20 controls. Circulating markers of endothelial damage (CEC, MPs and von Willebrand factor, vWF) and inflammation (E-selectin, E-sel; Interleukin-6, IL-6 and C-reactive protein, CRP) were determined. Subclinical atherosclerosis was assessed by carotid ultrasound to obtain intima-media thickness. Microcirculation was evaluated by nailfold capillaroscopy. RESULTS: CECs, MPs, vWF, CRP and E-sel levels were significantly elevated in patients when compared with controls (p <  0.05). Ninety-four and fifty-three percentage of patients had CEC and MP levels higher than 99th percentile in controls. Forty-seven percent of patients simultaneously showed increased CEC and MP levels. MPs correlate with the inflammatory markers and with the intima-media thickness. CECs correlate with the capillaries loops per mm (p <  0.05). CONCLUSION: Psoriasis patients show elevated CECs and MPs, as a sign of endothelial dysfunction, which correlates with inflammatory markers as well as subclinical atherosclerosis and some capillaroscopy findings.

Differential Impact of Relative Dose-Intensity Reductions in Diffuse Large B-Cell Lymphoma Treated with R-CHOP21 or R-CHOP14.

DLBCL is an aggressive lymphoma treated with R-CHOP. Recently, attempts have been made to improve the outcome by increasing both dose-density and intensity but there have been no benefits in terms of survival. When treating malignancies RDI is important to consider but there is little published information on DLBCL. The purpose of this study was to analyze the differential prognostic impact of RDI in two cohorts of DLBCL patients treated with R-CHOP21 or R-CHOP14. From January 2001 to August 2013 we included DLBCL patients homogenously treated with R-CHOP21 or R-CHOP14, with or without radiotherapy, at University Hospital Son Espases, Hospital Son Llatzer of Palma and Hospital del Mar of Barcelona (N = 157). In order to avoid selection bias the patients were retrospectively identified from the Pathology Department and Pharmacy registries. Median follow-up was 68 months. There was no difference in the response or survival between the two cohorts. In the R-CHOP21 group, both a reduction higher than 15% in RDI (RR 7.41) and R-IPI (RR 2.99) were independently associated with OS. However, a reduction higher than 15% in RDI (RR 4.41) was only noted for PFS. In the R-CHOP14 group, NCCN-IPI (RR 7.09) and B-symptoms (RR 5.37) for OS; AA stage III-IV (RR 6.26) and bulky disease (RR 4.05) for PFS. There was a trend towards a higher rate of RDI reduction observed in the R-CHOP14 group but it only made an impact in the R-CHOP21 group. We conclude that R-CHOP21 and R-CHOP14 are equivalent regimens in terms of response and survival, but only if RDI reductions are avoided. For patients receiving R-CHOP21 we recommend using clinical and support measures in order to avoid RDI reductions.

Four-channel asymmetric Real-Time PCR hybridization probe assay: a rapid pre-screening method for critical BCR-ABL kinase domain mutations.

OBJECTIVES: Within the laboratory protocols, used for the study of BCR-ABL resistance mutations in chronic myeloid leukemia patients treated with Imatinib, direct sequencing remains the reference method. Since the incidence of patients with a mutation-related loss of response is not very high, it is very useful in the routine laboratory to perform a fast pre-screening method. DESIGN AND METHODS: With this in mind, we have designed a new technique, based on a single Real-Time FRET-based PCR, followed by a study of melting peaks. This new tool, developed in a LightCycler 2.0, combines four different fluorescence channels for the simultaneous detection, in a single close tube, of critical mutations within the ABL kinase domain. RESULTS: Assay evaluation performed on 33 samples, previously genotyped by sequentiation, resulted in full concordance of results. CONCLUSIONS: This new methodology detects in a few steps the presence of critical mutations associated to Imatinib resistance.

Estudio del comportamiento de los lípidos en nuestro medio / Study of the behaviour of lipids in our environment

Se revisaron 311 historias clínicas, las que se clasificaron en 10 grupos, de acuerdo con las enfermedades presentadas por estos pacientes. Se estudiaron el porcentaje de casos patológicos por enfermedad, sus valores medios y la desviación típica, según el resultado del primer lipidograma que aparece en la historia clínica y se agruparon en función de las edades y los sexos, por último se compararon estos resultados con los obtenidos por otros autores