1
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Maxan A, Sciacca G, Alpaugh M, Tao Z, Breger L, Dehay B, Ling Z, Chuan Q, Cisbani G, Masnata M, Salem S, Lacroix S, Oueslati A, Bezard E, Cicchetti F. Use of adeno-associated virus-mediated delivery of mutant huntingtin to study the spreading capacity of the protein in mice and non-human primates. Neurobiol Dis 2020; 141:104951. [PMID: 32439599 DOI: 10.1016/j.nbd.2020.104951] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/20/2020] [Accepted: 05/16/2020] [Indexed: 01/27/2023] Open
Abstract
In order to model various aspects of Huntington's disease (HD) pathology, in particular protein spread, we administered adeno-associated virus (AAV) expressing green fluorescent protein (GFP) or GFP coupled to HTT-Exon1 (19Q or 103Q) to the central nervous system of adult wild-type (WT) mice and non-human primates. All animals underwent behavioral testing and post-mortem analyses to determine the long-term consequences of AAV injection. Both mice and non-human primates demonstrated behavioral changes at 2-3 weeks post-surgery. In mice, these changes were absent after 3 months while in non-human primates, they persisted in the majority of tested animals. Post-mortem analysis revealed that spreading of the aggregates was limited, although the virus did spread between synaptically-connected brain regions. Despite circumscribed spreading, the presence of mHTT generated changes in endogenous huntingtin (HTT) levels in both models. Together, these results suggest that viral expression of mHTTExon1 can induce spreading and seeding of HTT in both mice and non-human primates.
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Affiliation(s)
- Alexander Maxan
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Giacomo Sciacca
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Melanie Alpaugh
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Zhu Tao
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China
| | - Ludivine Breger
- Université de Bordeaux, Institut des maladies neurodégénératives, UMR 5293, CNRS UMR 5293, Bordeaux, France; Centre National de la Recherche Scientifique, Institut des maladies neurodégénératives, UMR 5293, 33076 Bordeaux, France
| | - Benjamin Dehay
- Université de Bordeaux, Institut des maladies neurodégénératives, UMR 5293, CNRS UMR 5293, Bordeaux, France; Centre National de la Recherche Scientifique, Institut des maladies neurodégénératives, UMR 5293, 33076 Bordeaux, France
| | - Zhang Ling
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China
| | - Qin Chuan
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China.
| | - Giulia Cisbani
- University of Toronto, Department of Nutritional Sciences, Toronto, ON M5S 1A8, Canada
| | - Maria Masnata
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Shireen Salem
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Steve Lacroix
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada; Département de Médicine Moléculaire, Université Laval, Québec, QC G1K 0A6, Canada
| | - Abid Oueslati
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada; Département de Médicine Moléculaire, Université Laval, Québec, QC G1K 0A6, Canada
| | - Erwan Bezard
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China; Université de Bordeaux, Institut des maladies neurodégénératives, UMR 5293, CNRS UMR 5293, Bordeaux, France; Centre National de la Recherche Scientifique, Institut des maladies neurodégénératives, UMR 5293, 33076 Bordeaux, France
| | - Francesca Cicchetti
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada; Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC G1K 0A6, Canada.
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Bartl S, Oueslati A, Southwell AL, Siddu A, Parth M, David LS, Maxan A, Salhat N, Burkert M, Mairhofer A, Friedrich T, Pankevych H, Balazs K, Staffler G, Hayden MR, Cicchetti F, Smrzka OW. Inhibiting cellular uptake of mutant huntingtin using a monoclonal antibody: Implications for the treatment of Huntington's disease. Neurobiol Dis 2020; 141:104943. [PMID: 32407769 DOI: 10.1016/j.nbd.2020.104943] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/08/2020] [Accepted: 05/06/2020] [Indexed: 12/24/2022] Open
Abstract
Huntington's disease (HD) is caused by a highly polymorphic CAG trinucleotide expansion in the gene encoding for the huntingtin protein (HTT). The resulting mutant huntingtin protein (mutHTT) is ubiquitously expressed but also exhibits the ability to propagate from cell-to-cell to disseminate pathology; a property which may serve as a new therapeutic focus. Accordingly, we set out to develop a monoclonal antibody (mAB) targeting a particularly exposed region close to the aa586 caspase-6 cleavage site of the HTT protein. This monoclonal antibody, designated C6-17, effectively binds mutHTT and is able to deplete the protein from cell culture supernatants. Using cell-based assays, we demonstrate that extracellular secretion of mutHTT into cell culture media and its subsequent uptake in recipient HeLa cells can be almost entirely blocked by mAB C6-17. Immunohistochemical stainings of post-mortem HD brain tissue confirmed the specificity of mAB C6-17 to human mutHTT aggregates. These findings demonstrate that mAB C6-17 not only successfully engages with its target, mutHTT, but also inhibits cell uptake suggesting that this antibody could interfere with the pathological processes of mutHTT spreading in vivo.
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Affiliation(s)
| | - Abid Oueslati
- Université Laval/Centre de recherche du CHU, Québec, Canada
| | | | - Alberto Siddu
- Université Laval/Centre de recherche du CHU, Québec, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | - Oskar W Smrzka
- AFFiRiS AG, Vienna, Austria; Ablevia biotech GmbH, Vienna, Austria
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Gosset P, Maxan A, Alpaugh M, Breger L, Dehay B, Tao Z, Ling Z, Qin C, Cisbani G, Fortin N, Vonsattel JPG, Lacroix S, Oueslati A, Bezard E, Cicchetti F. Evidence for the spread of human-derived mutant huntingtin protein in mice and non-human primates. Neurobiol Dis 2020; 141:104941. [PMID: 32422281 DOI: 10.1016/j.nbd.2020.104941] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/15/2020] [Accepted: 05/05/2020] [Indexed: 02/05/2023] Open
Abstract
In recent years, substantial evidence has emerged to suggest that spreading of pathological proteins contributes to disease pathology in numerous neurodegenerative disorders. Work from our laboratory and others have shown that, despite its strictly genetic nature, Huntington's disease (HD) may be another condition in which this mechanism contributes to pathology. In this study, we set out to determine if the mutant huntingtin protein (mHTT) present in post-mortem brain tissue derived from HD patients can induce pathology in mice and/or non-human primates. For this, we performed three distinct sets of experiments where homogenates were injected into the brains of adult a) Wild-type (WT) and b) BACHD mice or c) non-human primates. Neuropathological assessments revealed that, while changes in the endogenous huntingtin were not apparent, mHTT could spread between cellular elements and brain structures. Furthermore, behavioural differences only occurred in the animal model of HD which already overexpressed mHTT. Taken together, our results indicate that mHTT derived from human brains has only a limited capacity to propagate between cells and does not depict prion-like characteristics. This contrasts with recent work demonstrating that other forms of mHTT - such as fibrils of a pathological polyQ length or fibroblasts and induced pluripotent stem cells derived from HD cases - can indeed disseminate disease throughout the brain in a prion-like fashion.
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Affiliation(s)
- Philippe Gosset
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Alexander Maxan
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Melanie Alpaugh
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | - Ludivine Breger
- Université de Bordeaux, Institut des maladies neurodégénératives, UMR 5293, Bordeaux CNRS UMR 5293, France
| | - Benjamin Dehay
- Université de Bordeaux, Institut des maladies neurodégénératives, UMR 5293, Bordeaux CNRS UMR 5293, France
| | - Zhu Tao
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China
| | - Zhang Ling
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China
| | - Chuan Qin
- Institute of Laboratory Animal Sciences, China Academy of Medical Sciences, Beijing, China.
| | - Giulia Cisbani
- University of Toronto, Department of Nutritional Sciences, Toronto, ON M5S 1A8, Canada
| | - Nadia Fortin
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada
| | | | - Steve Lacroix
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada; Département de Médicine Moléculaire, Université Laval, Québec, QC G1K 0A6, Canada
| | - Abid Oueslati
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada; Département de Médicine Moléculaire, Université Laval, Québec, QC G1K 0A6, Canada
| | - Erwan Bezard
- Université de Bordeaux, Institut des maladies neurodégénératives, UMR 5293, Bordeaux CNRS UMR 5293, France
| | - Francesca Cicchetti
- Centre de Recherche du CHU de Québec - Université Laval, Axe Neurosciences, Québec, QC G1V 4G2, Canada; Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC G1K 0A6, Canada.
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Maxan A, Mason S, Saint-Pierre M, Smith E, Ho A, Harrower T, Watts C, Tai Y, Pavese N, Savage JC, Tremblay MÈ, Gould P, Rosser AE, Dunnett SB, Piccini P, Barker RA, Cicchetti F. Outcome of cell suspension allografts in a patient with Huntington's disease. Ann Neurol 2018; 84:950-956. [PMID: 30286516 PMCID: PMC6587549 DOI: 10.1002/ana.25354] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/27/2018] [Accepted: 09/27/2018] [Indexed: 12/22/2022]
Abstract
For patients with incurable neurodegenerative disorders such as Huntington's (HD) and Parkinson's disease, cell transplantation has been explored as a potential treatment option. Here, we present the first clinicopathological study of a patient with HD in receipt of cell-suspension striatal allografts who took part in the NEST-UK multicenter clinical transplantation trial. Using various immunohistochemical techniques, we found a discrepancy in the survival of grafted projection neurons with respect to grafted interneurons as well as major ongoing inflammatory and immune responses to the grafted tissue with evidence of mutant huntingtin aggregates within the transplant area. Our results indicate that grafts can survive more than a decade post-transplantation, but show compromised survival with inflammation and mutant protein being observed within the transplant site. Ann Neurol 2018;84:950-956.
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Affiliation(s)
- Alexander Maxan
- Centre de Recherche du CHU de Québec (CHUQ), Axe Neurosciences, Québec, QC, Canada
| | - Sarah Mason
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Martine Saint-Pierre
- Centre de Recherche du CHU de Québec (CHUQ), Axe Neurosciences, Québec, QC, Canada
| | - Emma Smith
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Aileen Ho
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Timothy Harrower
- Royal Devon and Exeter Hospital, Barrack Road, Exeter, Devon, United Kingdom
| | - Colin Watts
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Yen Tai
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Nicola Pavese
- Department of Medicine, Neurology Imaging Unit, Imperial College London, London, United Kingdom
| | - Julie C Savage
- Centre de Recherche du CHU de Québec (CHUQ), Axe Neurosciences, Québec, QC, Canada.,Département de médecine moléculaire, Université Laval, Québec, QC, Canada
| | - Marie-Ève Tremblay
- Centre de Recherche du CHU de Québec (CHUQ), Axe Neurosciences, Québec, QC, Canada.,Département de médecine moléculaire, Université Laval, Québec, QC, Canada
| | - Peter Gould
- Laboratoire de neuropathology, Hôpital de l'Enfant-Jésus-CHU de Québec, Québec, QC, United Kingdom
| | - Anne E Rosser
- Brain Repair Group and BRAIN unit, Neuroscience and Mental Health Research Institute and School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Stephen B Dunnett
- Brain Repair Group and BRAIN unit, Neuroscience and Mental Health Research Institute and School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Paola Piccini
- Department of Medicine, Neurology Imaging Unit, Imperial College London, London, United Kingdom
| | - Roger A Barker
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Francesca Cicchetti
- Centre de Recherche du CHU de Québec (CHUQ), Axe Neurosciences, Québec, QC, Canada.,Département de Psychiatrie & Neurosciences, Université Laval, Québec, QC, Canada
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Maxan A, Cicchetti F. Tau: A Common Denominator and Therapeutic Target for Neurodegenerative Disorders. J Exp Neurosci 2018; 12:1179069518772380. [PMID: 29760562 PMCID: PMC5946355 DOI: 10.1177/1179069518772380] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 12/13/2022] Open
Abstract
There is compelling evidence that a number of neurodegenerative diseases share common pathogenic mechanisms. Better understanding these mechanisms will allow us to develop new therapeutic strategies. This commentary follows up on our recent findings that tau pathology can be found in healthy fetal tissue transplanted into the brain of patients with either Huntington or Parkinson disease. We will examine how tau appears to be shared in a number of different conditions and how its expression relates to cognitive decline and disease progression. We will further review pathogenic mechanisms and especially the relevance of the possible prion-like behavior of tau. We will conclude by discussing how all this work opens up novel therapeutic approaches to treating the cognitive impairments related to neurodegenerative diseases using a common strategy.
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Affiliation(s)
- Alexander Maxan
- Axe Neurosciences, Centre de Recherche du CHU de Québec - Université Laval, Québec, QC, Canada
| | - Francesca Cicchetti
- Axe Neurosciences, Centre de Recherche du CHU de Québec - Université Laval, Québec, QC, Canada.,Département de Psychiatrie et de Neurosciences, Université Laval, Québec, QC, Canada
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Cisbani G, Maxan A, Kordower JH, Planel E, Freeman TB, Cicchetti F. Presence of tau pathology within foetal neural allografts in patients with Huntington's and Parkinson's disease. Brain 2017; 140:2982-2992. [PMID: 29069396 DOI: 10.1093/brain/awx255] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 08/05/2017] [Indexed: 11/12/2022] Open
Abstract
Cell replacement has been explored as a therapeutic strategy to repair the brain in patients with Huntington's and Parkinson's disease. Post-mortem evaluations of healthy grafted tissue in such cases have revealed the development of Huntington- or Parkinson-like pathology including mutant huntingtin aggregates and Lewy bodies. An outstanding question remains if tau pathology can also be seen in patients with Huntington's and Parkinson's disease who had received foetal neural allografts. This was addressed by immunohistochemical/immunofluorescent stainings performed on grafted tissue of two Huntington's disease patients, who came to autopsy 9 and 12 years post-transplantation, and two patients with Parkinson's disease who came to autopsy 18 months and 16 years post-transplantation. We show that grafts also contain tau pathology in both types of transplanted patients. In two patients with Huntington's disease, the grafted tissue showed the presence of hyperphosphorylated tau [both AT8 (phospho-tau Ser202 and Thr205) and CP13 (pSer202) immunohistochemical stainings] pathological inclusions, neurofibrillary tangles and neuropil threads. In patients with Parkinson's disease, the grafted tissue was characterized by hyperphosphorylated tau (AT8; immunofluorescent staining) pathological inclusions, neurofibrillary tangles and neuropil threads but only in the patient who came to autopsy 16 years post-transplantation. Abundant tau-related pathology was observed in the cortex and striatum of all cases studied. While the striatum of the grafted Huntington's disease patient revealed an equal amount of 3-repeat and 4-repeat isoforms of tau, the grafted tissue showed elevated 4-repeat isoforms by western blot. This suggests that transplants may have acquired tau pathology from the host brain, although another possibility is that this was due to acceleration of ageing. This finding not only adds to the recent reports that tau pathology is a feature of these neurodegenerative diseases, but also that tau pathology can manifest in healthy neural tissue transplanted into the brains of patients with two distinct neurodegenerative disorders.
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Affiliation(s)
- Giulia Cisbani
- Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, 2705 Boulevard Laurier, Québec, QC, Canada
| | - Alexander Maxan
- Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, 2705 Boulevard Laurier, Québec, QC, Canada
| | - Jeffrey H Kordower
- Department of Neurological Sciences and Center for Brain Repair, Rush University Medical Center, Chicago, IL 60612, USA
| | - Emmanuel Planel
- Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, 2705 Boulevard Laurier, Québec, QC, Canada.,Département de Psychiatrie and Neurosciences, Université Laval, Québec, QC, Canada
| | - Thomas B Freeman
- Department of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33606-3571, USA.,Center of Excellence for Aging and Brain Repair, University of South Florida, Tampa, FL 33606-3571, USA
| | - Francesca Cicchetti
- Centre de Recherche du CHU de Québec-Université Laval, Axe Neurosciences, 2705 Boulevard Laurier, Québec, QC, Canada.,Département de Psychiatrie and Neurosciences, Université Laval, Québec, QC, Canada
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Dumbarton TC, Maxan A, Farah N, Sharawy N, Zhou J, Nantais J, Lehmann C. Tetrahydrobiopterin improves microcirculation in experimental sepsis. Clin Hemorheol Microcirc 2017; 67:15-24. [PMID: 28598830 DOI: 10.3233/ch-160207] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Tetrahydrobiopterin (BH4), an endogenous nucleic acid derivative, acts as an important cofactor for several enzymes found within the vascular endothelium, which is deranged in sepsis. OBJECTIVE We hypothesized that BH4 would improve capillary density and decrease inflammation within the intestinal microcirculation of septic rats. METHODS We conducted a randomized, controlled trial using two previously validated models of sepsis in rats: 1) A fecal peritonitis model using a stent perforating the ascending colon, and 2) An endotoxemia model using lipopolysaccharide (LPS) toxin from E. coli. Experimental groups receiving BH4 (60 mg/kg) were compared to otherwise healthy controls and to untreated groups with sepsis-like physiology. RESULTS BH4 decreased leukocyte-endothelial adhesion by 55% and 58% (P < 0.05) in the peritonitis model and endotoxemia models, respectively. In the endotoxemia model but not the peritonitis model, BH4 improved functional capillary density in capillary beds within the intestine (141.3 vs. 106.7 mm/cm2, p < 0.05). Macrohemodynamic parameters were no different between placebo treatment and BH4-treated groups. CONCLUSIONS This study demonstrates that BH4 improves capillary density and inflammation in two separate models of sepsis. BH4 may represent a novel adjunct in the treatment of sepsis and septic shock in clinical practice. Further dose-finding studies and clinical trials are warranted.
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Affiliation(s)
- Tristan C Dumbarton
- Departments of Anesthesiology, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS, Canada
| | - Alexander Maxan
- Departments of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - Nizam Farah
- Departments of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - Nivin Sharawy
- Departments of Anesthesiology, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS, Canada
| | - Juan Zhou
- Departments of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - Jordan Nantais
- Department of General Surgery, Dalhousie University, Halifax, NS, Canada
| | - Christian Lehmann
- Departments of Anesthesiology, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS, Canada
- Departments of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
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Xia Y, Farah N, Maxan A, Zhou J, Lehmann C. Therapeutic iron restriction in sepsis. Med Hypotheses 2016; 89:37-9. [PMID: 26968906 DOI: 10.1016/j.mehy.2016.01.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/18/2016] [Accepted: 01/30/2016] [Indexed: 01/27/2023]
Abstract
Sepsis represents the systemic immune response to an infection. Mortality of sepsis slightly decreased over the past years, but due to the growing incidence, the absolute number of deaths still increases and belongs to the three most frequent causes of death worldwide. To date, there is no specific treatment for sepsis available yet. Iron is essential to both human beings and microbes and of great significance in many physiological and biochemical processes. Since iron is involved in the bacterial proliferation and immune dysregulation, we hypothesize that restricting host iron levels by application of iron chelators attenuates bacterial growth and improves the detrimental dysregulation of the systemic immune response in sepsis.
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Affiliation(s)
- Yanfang Xia
- School of Basic Medical Sciences, Zhejiang University, Zhejiang, China
| | - Nizam Farah
- Department of Pharmacology, Dalhousie University, Halifax, Canada
| | - Alexander Maxan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
| | - Juan Zhou
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada; Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada
| | - Christian Lehmann
- Department of Pharmacology, Dalhousie University, Halifax, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada; Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada
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Nantais J, Dumbarton TC, Farah N, Maxan A, Zhou J, Minor S, Lehmann C. Impact of methylene blue in addition to norepinephrine on the intestinal microcirculation in experimental septic shock. Clin Hemorheol Microcirc 2015; 58:97-105. [PMID: 25227191 DOI: 10.3233/ch-141874] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Methylene blue (MB) has been used with some success as a treatment for the vasoplegia of vasopressor-refractory septic shock. The putative mechanism of action of MB is the inhibition of endothelial nitric oxide within the microvasculature and improved responsiveness to endogenous catecholamines (norepinephrine (NE)). However, to date, no study has demonstrated the microcirculatory effect of methylene blue in septic shock. The objective of this randomized, controlled, animal study was to show, in an experimentally-induced, septic shock model in rats, the effects of MB and NE on global hemodynamics and the microcirculation. Mean arterial pressure (MAP) was drastically reduced following bacterial endotoxin (lipopolysaccharide, LPS) administration in animals not receiving vasopressors. Only the combination of NE + MB restored MAP to control levels by the end of the three hour experiment. Intravital microscopy of the microcirculation was performed in the terminal ileum in order to examine functional capillary density in intestinal muscle layers and the mucosa, as well as leukocyte activation in venules (rolling, adhesion to the endothelium). Untreated LPS animals showed a significant increase in leukocyte adhesion and a decrease in capillary perfusion in the intestinal microcirculation. In groups receiving NE or NE+MB, we observed a significant decrease in leukocyte adhesion and improved functional capillary density, indicating that microvasculature function was improved. This study suggests that methylene blue may be able to improve hemodynamics while preserving microvascular function in septic shock.
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Affiliation(s)
- Jordan Nantais
- Department of General Surgery, Dalhousie University, Halifax, Canada
| | - Tristan C Dumbarton
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada
| | - Nizam Farah
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
| | - Alexander Maxan
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
| | - Juan Zhou
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
| | - Samuel Minor
- Department of General Surgery, Dalhousie University, Halifax, Canada
| | - Christian Lehmann
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, Canada Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada Deparment of Pharmacology, Dalhousie University, Halifax, Canada
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