Carles Justicia

IDIBAPS August Pi i Sunyer Biomedical Research Institute | IDIBAPS · Division of Clinical and Experimental Neuroscience

Functional Magnetic Resonance Imaging (fMRI) in rodents is pivotal for understanding the mechanisms underlying Blood Oxygen Level-Dependent (BOLD) signals and phenotyping animal models of disorders, amongst other applications. Despite its growing use, comparing rodent fMRI results across different research sites remains challenging due to variation...

Hyperglycemia during early brain injury (EBI) period after spontaneous subarachnoid hemorrhage (SAH) is associated with poor outcome, but the underlying physiopathology is unknown. This study assessed if hyperglycemia during EBI is associated with markers of neuroaxonal injury and whether these biomarkers partially account for the association betwe...

Hyperglycemia has been linked to worsening outcomes after subarachnoid hemorrhage (SAH). Nevertheless, the mechanisms involved in the pathogenesis of SAH have been scarcely evaluated so far. The role of hyperglycemia was assessed in an experimental model of SAH by T 2 weighted, dynamic contrast-enhanced magnetic resonance imaging (T 2 W and DCE-MRI...

Background: Respiratory and urinary tract infections are frequent complications in patients with severe stroke. Stroke-associated infection is mainly due to opportunistic commensal bacteria of the microbiota that may translocate from the gut. We investigated the mechanisms underlying gut dysbiosis and poststroke infection. Methods: Using a model...

Brain CD11c+ cells share features with microglia and dendritic cells (DCs). Sterile inflammation increases brain CD11c+ cells, but their phenotype, origin, and functions remain largely unknown. We report that, after cerebral ischemia, microglia attract DCs to the inflamed brain, and astroglia produce Flt3 ligand, supporting development and expansio...

Inflammatory Ly6ChiCCR2+ monocytes infiltrate the brain after stroke but their functions are not entirely clear. We report that CCR2+ monocytes and CCR2+ lymphocytes infiltrate the brain after permanent ischemia. To underscore the role of CCR2+ monocytes, we generated mice with selective CCR2 deletion in monocytes. One day post-ischemia, these mice...

Noninvasive, three-dimensional, and longitudinal imaging of cerebral blood flow (CBF) in small animal models and ultimately in humans has implications for fundamental research and clinical applications. It enables the study of phenomena such as brain development and learning and the effects of pathologies, with a clear vision for translation to hum...

Hemorrhagic transformation (HT) is a complication of severe ischemic stroke after revascularization. Patients with low platelet counts do not receive reperfusion therapies due to high risk of HT. The immunomodulatory drug fingolimod attenuated HT after tissue plasminogen activator in a thromboembolic stroke model, but the underlying mechanism is un...

Background and Purpose— Ischemia attracts neutrophils to the injured brain. However, neutrophil location and access to the damaged brain tissue is not yet entirely understood. We aimed to investigate neutrophil location in a mouse model of cerebral ischemia/reperfusion. Methods— Adult male C57BL/6 mice (n=52) received 45-minute intraluminal middle...

Stroke attracts neutrophils to the injured brain tissue where they can damage the integrity of the blood–brain barrier and exacerbate the lesion. However, the mechanisms involved in neutrophil transmigration, location and accumulation in the ischemic brain are not fully elucidated. Neutrophils can reach the perivascular spaces of brain vessels afte...

The central nervous system (CNS) contains several types of immune cells located in specific anatomic compartments. Macrophages reside at the CNS borders surrounding the brain vessels, in leptomeningeal spaces and the choroid plexus, where they interact with the vasculature and play immunological surveillance and scavenging functions. We investigate...

Objective: Hemorrhagic transformation is a serious complication of ischemic stroke after recanalization therapies. This study aims to identify mechanisms underlying hemorrhagic transformation after cerebral ischemia/reperfusion. Approach and results: We used wild-type mice and Selplg-/- and Fut7-/- mice defective in P-selectin binding and lympho...

A new method for the tomographic monitoring of cerebral blood flow changes is presented. The method is based on speckle contrast optical tomography (SCOT) to recover 3D brain activation changes due to forepaw stimulation.

Neural activity is an important biomarker for the presence of neurodegenerative diseases, cerebrovascular alterations, and brain trauma; furthermore, it is a surrogate marker for treatment effects. These pathologies may occur and evolve in a long time-period, thus, noninvasive, transcutaneous techniques are necessary to allow a longitudinal follow-...

Molecular Psychiatry publishes work aimed at elucidating biological mechanisms underlying psychiatric disorders and their treatment

Hyperglycemia at stroke onset is associated with poor long-term clinical outcome in numerous studies. Hyperglycemia induces intracellular acidosis, lipid peroxidation, and peroxynitrite production resulting in the generation of oxidative and nitrosative stress in the ischemic tissue. Here, we studied the effects of acute hyperglycemia on in vivo in...

High-density speckle contrast optical tomography (SCOT) utilizing tens of thousands of source-detector pairs, was developed for in vivo imaging of blood flow in small animals. The reduction in cerebral blood flow (CBF) due to local ischemic stroke in a mouse brain was transcanially imaged and reconstructed in three dimensions. The reconstructed vol...

Induction of neuroprotective heat-shock proteins via pharmacological Hsp90 inhibitors is currently being investigated as a potential treatment for neurodegenerative diseases. Two major hurdles for therapeutic use of Hsp90 inhibitors are systemic toxicity and limited central nervous system permeability. We demonstrate here that chronic treatment wit...

High-density speckle contrast optical tomography (SCOT) has been developed to image cerebral blood flow through intact skull in mice during ischemic stroke. The results are quantified and compared to magnetic resonance imaging.

Speckle contrast optical tomography allows for high-density measurement of deep tissue blood flow. With this technique we demonstrate obtain three-dimensional reconstructions of blood flow in deep tissues using novel algorithms and detector arrays.

A new approach for multi-exposure laser speckle contrast imaging (MESI) which exploits a novel single-photon avalanche diode array is presented. High frame-rate and sensitivity allow rapid single-shot acquisition MESI in phantoms and small animals.

Acute stroke induces a local inflammatory reaction causing leukocyte infiltration. Circulating monocytes are recruited to the ischemic brain and become tissue macrophages morphologically indistinguishable from reactive microglia. However, monocytes are a heterogeneous population of cells with different functions. Herein, we investigated the infiltr...

Laser speckle contrast imaging (LSCI) has emerged as a valuable tool for cerebral blood flow (CBF) imaging. We present a multi-exposure laser speckle imaging (MESI) method which uses a high-frame rate acquisition with a negligible inter-frame dead time to mimic multiple exposures in a single-shot acquisition series. Our approach takes advantage of...

Neutrophils are rapidly recruited in response to local tissue infection or inflammation. Stroke triggers a strong inflammatory reaction but the relevance of neutrophils in the ischemic brain is not fully understood, particularly in the absence of reperfusion. We investigated brain neutrophil recruitment in two murine models of permanent ischemia in...

Several lines of evidence support the involvement of mannose-binding lectin (MBL) in stroke brain damage. The lectin pathway of the complement system facilitates thrombin activation and clot formation under certain experimental conditions. In the present study, we examine whether MBL promotes thrombosis after ischemia/reperfusion and influences the...

Under several adverse conditions, such as hypoxia or ischemia, extracellular levels of adenosine (Ado) upraise due to increased energy demands and ATP metabolism. Because extracellular Ado affects metabolism through G protein-coupled receptors, its regulation is of high adaptive importance. Concentrative nucleoside transporter 2 (CNT2) may play phy...

Background Citicoline is one of the neuroprotective agents that have been used as a therapy in stroke patients. There is limited published data describing the mechanisms through which it acts. Methods We used in vitro angiogenesis assays: migration, proliferation, differentiation into tube-like structures in Matrigel™ and spheroid development assa...

Figure S1. Kinexus bar chart.

Purpose: Stroke induces strong expression of the 72-kDa heat-shock protein (HSP-70) in the ischaemic brain, and neuronal expression of HSP-70 is associated with the ischaemic penumbra. The aim of this study was to image induction of Hsp-70 gene expression in vivo after brain ischaemia using reporter mice. Methods: A genomic DNA sequence of the H...

Diffusion tensor imaging is being increasingly used as a means to elucidate the brain's fiber structure. High spatial resolution is needed to capture details of the anatomy for tractography. However, image deteriorating factors such as low contrast-to-noise ratio, partial volume effects and subject's displacements affect the analysis. We introduce...

Background and purposes - Citicoline is neuroprotective agent used in stroke patients. Citicoline induces angiogenesis i n vitro ; however, the molecular mechanisms induced by citicoline have not been fully investigated. The present study was designed to investigate the key signalling mechanisms through which citicoline modulates angiogenesis-assoc...

Regenerative strategies of stem cell grafting have been demonstrated to be effective in animal models of stroke. In those studies, the effectiveness of stem cells promoting functional recovery was assessed by behavioral testing. These behavioral studies do, however, not provide access to the understanding of the mechanisms underlying the observed f...

Extended methods (0.04 MB DOC)

Main traits in patients with ischemic or hemorrhagic stroke. (0.03 MB DOC)

Balance between T helper (h) 1 cytokines and Th2 cytokines and clinical outcome. Serum measurements at day 0 (d0) (n = 129); day 1 (d1) (n = 121); day 2 (d2) (n = 122); day 3 (d3) (n = 116); day 4 (d4) (n = 111), day 7 (d7) (n = 101), and day 90 (d90) (n = 92). Values are mean ± SD. *p<0.05. (0.67 MB TIF)

Complement system activation in carriers of D105>G and WT MASP2-genotypes. Serum concentration (g/L) of C3 and C4 at day 0 (d0) (n = 96) and day 2 (d2) (n = 96). Values are represented as mean±SD. (2.05 MB TIF)

The complement system is a major effector of innate immunity that has been involved in stroke brain damage. Complement activation occurs through the classical, alternative and lectin pathways. The latter is initiated by mannose-binding lectin (MBL) and MBL-associated serine proteases (MASPs). Here we investigated whether the lectin pathway contribu...

Manganese-enhanced MRI (MEMRI) has been described as a powerful tool to depict the architecture of neuronal circuits. The aim of the present study was to optimize the experimental conditions of MEMRI that permits the study of insult-induced alterations of the somatosensory pathway in a longitudinal way, and to provide functional information on rat...

Iron plays a central role in many metabolic processes. Under certain pathological situations it accumulates, producing negative effects such as increasing damage by oxidative stress. The present study examined long-term iron accumulation in a stroke model with secondary degeneration, using MRI and histological techniques. Male Wistar rats (n=22) we...

Therapeutic success of treatment of cerebral diseases must be assessed in terms of functional outcome. In experimental stroke studies, this has been limited to behavioral studies combined with morphological evaluations and single time point functional magnetic resonance imaging (fMRI) measurements but lacking the access to understanding underlying...

Cell tracking by in vivo magnetic resonance imaging (MRI) requires strategies of labelling the cells with MRI contrast agents. The principal routes to achieve efficient cell labelling for neurological applications are discussed with methodological advantages and caveats. Beyond temporo-spatial localization of labelled cells, the investigation of fu...

Transient focal cerebral ischemia in the rat alters vessel properties, and spontaneously hypertensive rats (SHR) show a poorer outcome after ischemia. In the present study we examined the role of hypertension on vessel properties after ischemia-reperfusion. The right middle cerebral artery (MCA) was occluded (90 min) and reperfused (24 h) in SHR (n...

It has been shown that insoluble Gd chelates are suitable MRI contrast agents for conditional activation by intracellular lipases. The DTPA-based, insoluble, inactive contrast agent was internalized into dendritic cells by phagocytosis. Cleavage of long aliphatic side chains by intracellular lipase activity leads to the contrast agents solubility a...

Diffusion-weighted imaging (DWI) hyperintensities and apparent diffusion coefficient (ADC) hypointensities are MRI features of acute stroke. DWI alterations during ischemia recover with early reperfusion, but they can reappear later. Pronounced signal abnormalities early after stroke are associated with infarction, but the significance of subtle ch...

Cerebral ischemia triggers an inflammatory process involving the infiltration of leukocytes to the parenchyma. Circulating leukocytes adhere to the vascular wall through adhesion molecules. Here we quantified the in vivo expression of vascular cell adhesion molecule-1 (VCAM-1) in the brain, heart and lungs from 6 to 48 h after transient middle cere...

Unfractionated heparin (UH) decreases the extent of infarction after transient focal brain ischemia in the rat and abridges neuroinflammatory damage in patients with acute stroke. This study was aimed at assessing whether controlled and steady heparinemia in plasma can reduce infarct volume and exert neuroprotective effects after ischemia. Infarct...

Matrix metalloproteinase-9 (MMP-9) activity increases in the brain during the first day after focal ischemia and might be involved in the pathogenesis of tissue damage. We previously showed MMP-9 in the extracellular space of brain parenchyma along with neutrophil recruitment after ischemia. In the present study, we tested whether neutrophils were...

Transient focal ischaemia by middle cerebral artery occlusion (MCAO) may produce cell death, but the mechanisms leading to cell death differ in the infarct core and in the penumbra, the immediate zone surrounding the infarct core. In the present study, transient focal ischaemia to adult rats was produced by intraluminal occlusion of the middle cere...

Cerebral ischemia activates ERK and Akt pathways. We studied whether these activations were affected by treatment with the protective growth factor transforming growth factor-alpha (TGF-alpha), and whether they were mediated through N-methyl D-aspartate (NMDA) receptors. The middle cerebral artery was occluded in rats and signaling was studied 1 h...

Matrix metalloproteinases (MMPs) are activated in focal cerebral ischemia. The activation of MMP-9 is involved in blood-brain barrier breakdown and tissue remodeling. The MMPs are released to the extracellular space, but the form and fate of secreted enzymes in brain are unknown. Using microdialysis in vivo, the authors studied whether ischemia-ind...

We studied whether pro-survival Akt was activated after transient focal cerebral ischemia and whether it inhibited pro-apoptotic Bad. Phosphorylation of Akt (serine-473) was enhanced in cortex after 1-hour ischemia, and also after 1h and 6 h of reperfusion, but it returned back to that in controls by 24 h. After this first wave of Akt activation, a...

Matrix metalloproteinases (MMPs) degrade the extracellular matrix and carry out key functions during development and after injury. By means of zymography, Western blot and immunohistochemistry, we studied MMP-2 (gelatinase A) and MMP-9 (gelatinase B) in rat brain after focal cerebral ischemia. The control rat brain showed constitutive MMP-2 and, to...

Growth factors promote cell growth and survival and protect the brain from developing injury after ischemia. In this article, the authors examined whether transforming growth factor-alpha (TGF-alpha) was protective in transient focal ischemia and whether alteration of cerebral circulation was involved. Rats received intraventricular TGF-alpha (50 n...

The role of gene induction (expression of HSP72 and c-JUN proteins) and delayed ischemic cell death (in situ labeling of DNA fragmentation) have been investigated in the goat hippocampus after transient global cerebral ischemia. The animals were subjected to 20-min ischemia (bilateral occlusion of the external carotid arteries plus bilateral jugula...

Matrix metalloproteinases degrade the extracellular matrix and are involved in a variety of diseases, including inflammatory diseases of the central nervous system. Here we estimated the content of gelatinase in rat brain under control conditions and 4 h after transient focal ischemia using gelatinolytic extraction and zymographic analysis. We also...

JAK/STAT is one of the pathways bearing signals from the cell membrane to the nucleus in response to extracellular growth factors and cytokines. In the present study, we examined the cellular distribution of Jak1 and Stat3, and activation of the JAK/STAT pathway following transient focal cerebral ischemia in the rat. Jak1 was mainly seen in white m...

Cyclooxygenase-2, a key enzyme in prostanoid synthesis, is induced by inflammatory stimuli and it is associated with cell death after cerebral ischemia. Here we evaluated whether cyclooxygenase-2 was induced after a short (10-min) episode of focal ischemia, mild enough not to cause inflammation or cell death. One-hour ischemia leading to brain infa...