Tiago Granja - Academia.edu (original) (raw)

Papers by Tiago Granja

Journal of Visualized Experiments

Symmetry, 2022

Physiological perfusion asymmetries in the lower limb are known, although poorly understood, as a... more Physiological perfusion asymmetries in the lower limb are known, although poorly understood, as are asymmetries reported in plantar pressure and stance. This preliminary study aims to explore potential relationships between perfusion and pressure variables in humans. A convenience sample of eight healthy individuals (25.25 ± 5.37 years old) of both sexes, was selected. Chosen variables were perfusion, plantar pressure, and stance. Perfusion was measured in both feet by laser Doppler flowmetry (LDF) and polarized light spectroscopy (PSp), and plantar pressure and stance obtained by a pressure plate. These were measured in baseline (Phase I) in a repeated squatting (Phase II), and in recovery (Phase III). A 95% confidence interval was adopted. Intraindividual significant perfusion asymmetries between both feet were detected by LDF in Phase I. These disappeared in Phase II and returned in Phase III. PSp did not detect any asymmetries. Plantar pressure was also asymmetric and differentl...

Recent evidence has demonstrated additional roles for the neuronal guidance protein receptor UNC5... more Recent evidence has demonstrated additional roles for the neuronal guidance protein receptor UNC5B outside the nervous system. Given the fact that ischemia reperfusion injury (IRI) of the liver is a common source of liver dysfunction and the role of UNC5B during an acute inflammatory response we investigated the role of UNC5B on acute hepatic IRI. We report here that UNC5B+/2 mice display reduced hepatic IRI and neutrophil (PMN) infiltration compared to WT controls. This correlated with serum levels of lactate dehydrogenase (LDH), aspartate- (AST) and alanine- (ALT) aminotransferase, the presence of PMNwithin ischemic hepatic tissue, and serum levels of inflammatory cytokines. Moreover, injection of an anti-UNC5B antibody resulted in a significant reduction of hepatic IR injury. This was associated with reduced parameters of liver injury (LDH, ALT, AST) and accumulation of PMN within the injured hepatic tissue. In conclusion our studies demonstrate a significant role for UNC5B in th...

G-protein-coupled receptors (GPCRs) are the most abundant receptors in the heart and therefore ar... more G-protein-coupled receptors (GPCRs) are the most abundant receptors in the heart and therefore are common targets for cardiovascular therapeutics. The activated GPCRs transduce their signals via heterotrimeric G-proteins. The four major families of G-proteins identified so far are specified through their a-subunit: Gai, Gas, Gaq and G12/13. Gai-proteins have been reported to protect hearts from ischemia reperfusion injury. However, determining the individual impact of Gai2 or Gai3 on myocardial ischemia injury has not been clarified yet. Here, we first investigated expression of Gai2 and Gai3 on transcriptional level by quantitative PCR and on protein level by immunoblot analysis as well as by immunofluorescence in cardiac tissues of wild-type, Gai2-, and Gai3-deficient mice. Gai2 was expressed at higher levels than Gai3 in murine hearts, and irrespective of the isoform being knocked out we observed an up regulation of the remaining Gai-protein. Myocardial ischemia promptly regulate...

Copyright: © 2015 The PLOS ONE Staff. This is an open access article distributed under the terms ... more Copyright: © 2015 The PLOS ONE Staff. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are

Journal Biomedical and Biopharmaceutical Research, 2022

Tomographic imaging is a well established technology in preventive medicine and biomedical resear... more Tomographic imaging is a well established technology in preventive medicine and biomedical research, although not without limitations and concerns. Optoacoustic tomography (OAT) is a recent development that bridges optical and sonographic techniques to solve spatial resolution in deep-tissue imaging. In addition to safety advantages, OAT allows multiple wavelength readings for natural thermoelastic chromophores. In this study, we explore Multi Spectral Optoacoustic Tomography (MSOT) capacities to simultaneously acquire three independent chromophores – deoxygenated haemoglobin (Hb), oxygenated haemoglobin (HbO2), and melanin, from healthy human volunteers, with maximal molar extinction of HbO2 at 950 nm, Hb at 750 nm and melanin at 680 nm. Later we demonstrate how image stability during acquisition is fundamental for optimal resolution, precision and consistency of high throughout MSOT data collection. From recorded scans, a workflow is layered for data evaluation. With the MSOT dedi...

ABSTRACTPulmonary defense mechanisms are critical for host integrity during the early phase of pn... more ABSTRACTPulmonary defense mechanisms are critical for host integrity during the early phase of pneumonia and sepsis. These processes are fundamentally dependent on the activation of neutrophils during the early phase of the innate immune response. Recent work has shown that semaphorin 7A (Sema7A) holds significant impact on platelet activation, yet its role in neutrophil migration and function is not well known. We report here that Sema7A binds to neutrophil PlexinC1, increasing integrins and L-selectin on the neutrophil surface. Sema7A-induced neutrophil activation also prompted neutrophil chemotaxis in vitro and the formation of platelet-neutrophil complexes in vivo. We also observed altered adhesion and transmigration of neutrophils in Sema7A-/- animals in the lung. Sema7A-/- animals also showed altered crawling properties of neutrophils. This resulted in increased number of neutrophils in the interstitial space of Sema7A-/- animals but reduced numbers of neutrophils in the alveo...

Critical Care Medicine, 2020

Nature Communications, 2020

Myocardial ischemia is one of the leading health problems worldwide. Therapy consists of the rest... more Myocardial ischemia is one of the leading health problems worldwide. Therapy consists of the restitution of coronary perfusion which is followed by myocardial inflammation. Platelet–neutrophil interaction is a crucial process during inflammation, yet its consequences are not fully understood. Here, we show that platelet–neutrophil complexes (PNCs) are increased in patients with acute myocardial infarction and that this is associated with increased levels of neuronal guidance protein semaphorin 7A (SEMA7A). To investigate this further, we injected WT animals with Sema7a and found increased infarct size with increased numbers of PNCs. Experiments in genetically modified animals identify Sema7a on red blood cells to be crucial for this condition. Further studies revealed that Sema7a interacts with the platelet receptor glycoprotein Ib (GPIb). Treatment with anti-Sema7a antibody protected from myocardial tissue injury. In summary, we show that Sema7a binds to platelet GPIb and enhances ...

Critical Care Medicine, 2019

Objectives: Sepsis is associated with a systemic inflammatory reaction, which can result in a lif... more Objectives: Sepsis is associated with a systemic inflammatory reaction, which can result in a life-endangering organ dysfunction. Pro-inflammatory responses during sepsis are characterized by increased activation of leukocytes and platelets, formation of platelet-neutrophil aggregates, and cytokine production. Sequestration of platelet-neutrophil aggregates in the microvasculature contributes to tissue damage during sepsis. At present no effective therapeutic strategy to ameliorate these events is available. In this preclinical pilot study, a novel anti-inflammatory approach was evaluated, which targets nucleoside triphosphate hydrolase activity toward activated platelets via a recombinant fusion protein combining a single-chain antibody against activated glycoprotein IIb/IIIa and the extracellular domain of CD39 (targ-CD39). Design: Experimental animal study and cell culture study. Setting: University-based experimental laboratory. Subjects: Human dermal microvascular endothelial cells 1, human platelets and neutrophils, and C57BL/6NCrl mice. Interventions: Platelet-leukocyte-endothelium interactions were evaluated under inflammatory conditions in vitro and in a murine lipopolysaccharide-induced sepsis model in vivo. The outcome of polymicrobial sepsis was evaluated in a murine cecal ligation and puncture model. To evaluate the anti-inflammatory potential of activated platelet targeted nucleoside triphosphate hydrolase activity, we employed a potato apyrase in vitro and in vivo, as well as targ-CD39 and as a control, nontarg-CD39 in vivo. Measurements and Main Results: Under conditions of sepsis, agents with nucleoside triphosphate hydrolase activity decreased platelet-leukocyte-endothelium interaction, transcription of proinflammatory cytokines, microvascular platelet-neutrophil aggregate sequestration, activation marker expression on platelets and neutrophils contained in these aggregates, leukocyte extravasation, and organ damage. Targ-CD39 had the strongest effect on these variables and retained hemostasis in contrast to nontarg-CD39 and potato apyrase. Most importantly, targ-CD39 improved survival in the cecal ligation and puncture model to a stronger extent then nontarg-CD39 and potato apyrase. Conclusions: Targeting nucleoside triphosphate hydrolase activity (CD39) toward activated platelets is a promising new treatment concept to decrease systemic inflammation and mortality of sepsis. This innovative therapeutic approach warrants further development toward clinical application. (Crit Care Med 2019; 47:e420-e427)

<p>WT animals treated with an anti-UNC5B antibody or Immunoglobulin (IgG) prior to the indu... more <p>WT animals treated with an anti-UNC5B antibody or Immunoglobulin (IgG) prior to the induction of IRI. A) LDH, B) ALT, C) AST in the serum was analysed (Data are mean ± SEM, n = 6 per condition). D) Representative pictures of TTC stained liver lobes are shown (n = 4 per condition).</p

Anesthesiology, Sep 11, 2016

Liver ischemia/reperfusion (IR) injury is characterized by hepatic tissue damage and an inflammat... more Liver ischemia/reperfusion (IR) injury is characterized by hepatic tissue damage and an inflammatory response. This is accompanied by the formation and vascular sequestration of platelet-neutrophil conjugates (PNCs). Signaling through Adora2b adenosine receptors can provide liver protection. Volatile anesthetics may interact with adenosine receptors. This study investigates potential antiinflammatory effects of the volatile anesthetic sevoflurane during liver IR. Experiments were performed ex vivo with human blood and in a liver IR model with wild-type, Adora2a, and Adora2b mice. The effect of sevoflurane on platelet activation, PNC formation and sequestration, cytokine release, and liver damage (alanine aminotransferase release) was analyzed using flow cytometry, luminometry, and immunofluorescence. Adenosine receptor expression in liver tissue was analyzed using immunohistochemistry and real-time polymerase chain reaction. Ex vivo experiments indicate that sevoflurane inhibits pla...

Critical care medicine, Jan 9, 2016

Hepatic ischemia-reperfusion injury is a disease pattern that is associated with an acute inflamm... more Hepatic ischemia-reperfusion injury is a disease pattern that is associated with an acute inflammatory reaction. It is well known that neutrophils play an essential role in the early phase of hepatic ischemia-reperfusion injury and determine the extent of tissue damage. Hepatic ischemia-reperfusion injury can result in organ failure, which is linked to high mortality. Recent data indicate that the neuronal guidance receptor Plexin C1 is involved in the control of the acute inflammatory response and, as such, modulates the transmigration of neutrophils. Hence, we investigated the functional role of Plexin C1 in a mouse model of early hepatic ischemia-reperfusion injury. Animal study. University experimental laboratory. Wild-type, PLXNC1 and chimeric mice. Hepatic ischemia-reperfusion injury or sham operation. We found that the functional inhibition of Plexin C1 in wild-type mice treated with an anti-Plexin C1 antibody and a Semaphorin 7A peptide reduced hepatic ischemia-reperfusion i...

PLOS ONE, 2016

The extent of pulmonary inflammation during lung injury ultimately determines patient outcome. Pu... more The extent of pulmonary inflammation during lung injury ultimately determines patient outcome. Pulmonary inflammation is initiated by the migration of neutrophils into the alveolar space. Recent work has demonstrated that the guidance protein semaphorin 7A (SEMA7A) influences the migration of neutrophils into hypoxic tissue sites, yet, its role during lung injury is not well understood. Here, we report that the expression of SEMA7A is induced in vitro through pro-inflammatory cytokines. SEMA7A itself induces the production of proinflammatory cytokines in endothelial and epithelial cells, enhancing pulmonary inflammation. The induction of SEMA7A facilitates the transendothelial migration of neutrophils. In vivo, animals with deletion of SEMA7A expression showed reduced signs of pulmonary inflammatory changes following lipopolysaccharide challenge. We define here the role of SEMA7A in the development of lung injury and identify a potential pathway to interfere with these detrimental changes. Future anti-inflammatory strategies for the treatment of lung injury might be based on this finding.

Journal of Experimental Medicine, 2014

Resolution of inflammation is now recognized as a biosynthetically active process involving pro-r... more Resolution of inflammation is now recognized as a biosynthetically active process involving pro-resolving mediators. Here, we show in zymosan-initiated peritoneal inflammation that the vagus nerve regulates local expression of netrin-1, an axonal guidance molecule that activates resolution, and that vagotomy reduced local pro-resolving mediators, thereby delaying resolution. In netrin-1+/− mice, resolvin D1 (RvD1) was less effective in reducing neutrophil influx promoting resolution of peritonitis compared with Ntn1+/+. Netrin-1 shortened the resolution interval, decreasing exudate neutrophils, reducing proinflammatory mediators, and stimulating the production of resolvins, protectins, and lipoxins. Human monocytes incubated with netrin-1 produced proresolving mediators, including resolvins and lipoxins. Netrin-1 and RvD1 displayed bidirectional activation in that they stimulated each other’s expression and enhanced efferocytosis. These results indicate that the vagus nerve regulate...