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Abstract
Myeloperoxidase (MPO) belongs to the heme peroxidase family, which includes a set of enzymes with potent oxidoreductase activity. MPO is considered an important part of the innate immune system's microbicidal arm and is secreted by neutrophils and macrophages. Interestingly, this enzyme has been implicated in the pathogenesis of several diseases including atherosclerosis. MPO is ubiquitous in atherosclerotic lesions and contributes to the initiation and progression of the disease primarily by oxidizing low-density lipoprotein (LDL) particles. MPO is the only human enzyme with the ability to produce hypochlorous acid (HOCl) at physiological chloride concentrations and HOCl-LDL epitopes were shown to be present inside atheromatous lesions making it a physiologically relevant model for the oxidation of LDL. It has been shown that MPO modified LDL is not able to bind to the native LDL receptor and is recognized instead by scavenger receptors on both endothelial cells and macrophages, which can lead to endothelial dysfunction and foam cell formation, respectively; both of which are instrumental in the progression of the disease. Meanwhile, several studies have proposed MPO as a biomarker for cardiovascular diseases where high levels of this enzyme were linked to an increased risk of developing coronary artery disease. Overall, there is sufficient evidence supporting the value of MPO as a crucial player in health and disease. Thus, future research should be directed towards investigating the still unknown processes associated with this enzyme. This may assist in better understanding the pathophysiological role of MPO, as well in the development of therapeutic strategies for protecting against the deleterious effects of MPO in numerous pathologies such as atherosclerosis.
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Affiliation(s)
- Christian Frangie
- Department of Biology, Faculty of Arts and Sciences, University of Balamand, El‑Koura 100, Lebanon
| | - Jalil Daher
- Department of Biology, Faculty of Arts and Sciences, University of Balamand, El‑Koura 100, Lebanon
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Abstract
Macrophages (Mφs) play a crucial role in the development of atherosclerosis by engulfing modified LDL particles and forming foam cells, the hallmark of atherosclerosis. Many studies suggest that myeloperoxidase-oxidized LDL (Mox-LDL) is an important pathophysiological model for LDL modification in vivo. Classically (M1) and alternatively activated (M2) Mφs are both implicated in the process of atherogenesis. Mφs are highly plastic cells whereby they undergo repolarization from M1 to M2 and vice versa. Since little is known about the effects of Mox-LDL on Mφ polarization and repolarization, our study aimed at evaluating the in vitro effects of Mox-LDL at this level through making use of the well-established model of human THP-1-derived Mφs. Resting M0-Mφs were polarized toward M1- and M2-Mφs, then M0-, M1- and M2-Mφs were all treated with physiological concentrations of Mox-LDL to assess the effect of Mox-LDL treatment on Mφ polarization and repolarization. Treatment of M0-Mφs with a physiological concentration of Mox-LDL had no significant effects at the level of their polarization. However, treatment of M1-Mφs with Mox-LDL resulted in a significant reduction in their IL-10 cytokine secretion. Our results point to a potential role of Mox-LDL in increasing the pro-inflammatory state in Mφs through reducing the release of the anti-inflammatory cytokine, IL-10.
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Affiliation(s)
- Samer Bazzi
- Department of Biology, Faculty of Arts and Sciences, 54686University of Balamand, El-Koura, Lebanon
| | - Christian Frangie
- Department of Biology, Faculty of Arts and Sciences, 54686University of Balamand, El-Koura, Lebanon
| | - Eliana Azar
- Department of Biology, Faculty of Arts and Sciences, 54686University of Balamand, El-Koura, Lebanon
| | - Jalil Daher
- Department of Biology, Faculty of Arts and Sciences, 54686University of Balamand, El-Koura, Lebanon
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Abstract
It is hypothesized that several comorbidities increase the severity of COVID-19 symptoms. Cardiovascular disease including hypertension was shown to play a critical role in the severity of COVID-19 infection by affecting the survival of patients with COVID-19. Hypertension and the renin-angiotensin-aldosterone system are involved in increasing vascular inflammation and endothelial dysfunction (ED), and both processes are instrumental in COVID-19. Angiotensin-converting enzyme 2 is an essential component of the renin-angiotensin-aldosterone system and the target receptor that mediates SARS-CoV-2 entry to the cell. This led to speculations that major renin-angiotensin-aldosterone system inhibitors, such as angiotensin receptor blockers and angiotensin-converting enzyme inhibitors might affect the course of the disease, since their administration enhances angiotensin-converting enzyme (ACE)2 expression. An increase in ACE2 activity could reduce angiotensin II concentration in the lungs and mitigate virus-driven lung injury. This could also be associated with a reduction in blood coagulation, which plays a critical role in the pathogenesis of SARS-CoV-2; of note, COVID-19 is now regarded as a disorder of blood clotting. Therefore, there is an urgent need to better understand the effect of targeting ACE2 as a potential treatment for SARS-CoV-2 driven injury, and in alleviating COVID-19 symptoms by reversing SARS-CoV-2-induced excessive coagulation and fatalities. Ongoing therapeutic strategies that include recombinant human ACE2 and anti-spike monoclonal antibodies are essential for future clinical practice in order to better understand the effect of targeting ED in COVID-19.
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Affiliation(s)
- Jalil Daher
- Department of Biology, Faculty of Arts and Sciences, University of Balamand, Tripoli PO Box 100, Lebanon
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Daher J, Da Costa A, Hilaire C, Ferreira T, Pierrard R, Guichard J, Romeyer C, Isaaz K. Management of left ventricular thrombi with direct oral anticoagulants: Retrospective comparative study with vitamin K antagonists. Archives of Cardiovascular Diseases Supplements 2021. [DOI: 10.1016/j.acvdsp.2020.10.167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Daher J. Effect of myeloperoxidase modified LDL on bovine and human aortic endothelial cells. Atherosclerosis 2020. [DOI: 10.1016/j.atherosclerosis.2020.10.334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chidiac M, Daher J, Boeckstaens M, Poelvoorde P, Badran B, Marini AM, Khalaf R, Vanhamme L. Human apolipoprotein L1 interferes with mitochondrial function in Saccharomyces cerevisiae. Mol Med Rep 2020; 22:1910-1920. [PMID: 32583004 PMCID: PMC7411449 DOI: 10.3892/mmr.2020.11271] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 10/20/2019] [Accepted: 04/24/2020] [Indexed: 11/17/2022] Open
Abstract
To the best of our knowledge, the vertebrate apolipoprotein L (APOL) family has not previously been ascribed to any definite pathophysiological function, although the conserved BH3 protein domain suggests a role in programmed cell death or an interference with mitochondrial processes. In the present study, the human APOL1 was expressed in the yeast Saccharomyces cerevisiae in order to determine the molecular action of APOL1. APOL1 inhibited cell proliferation in a non-fermentable carbon source, such as glycerol, while it had no effect on proliferation in fermentable carbon sources, such as galactose. APOL1, expressed in yeast, is localized in the mitochondrial fraction, as determined via western blotting. APOL1 induced a loss of mitochondrial function, demonstrated by a loss of respiratory index, and mitochondrial membrane potential. Green fluorescent protein tagging of mitochondrial protein revealed that APOL1 was associated with abnormal mitochondrial and lysosomal morphologies, observed by a loss of the normal mitochondrial tubular network. Thus, the results of the present study suggest that APOL1 could be a physiological regulator of mitochondrial function.
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Affiliation(s)
- Mounia Chidiac
- Laboratory of Molecular Parasitology, Laboratory of Gene Molecular Biology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Jalil Daher
- Department of Biology, University of Balamand, P.O. Box 100, Tripoli, Lebanon
| | - Mélanie Boeckstaens
- Laboratory of Membrane Transport Biology, IBMM, Faculty of Sciences, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Philippe Poelvoorde
- Laboratory of Molecular Parasitology, Laboratory of Gene Molecular Biology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Bassam Badran
- Department of Biochemistry, Laboratory of Immunology, Lebanese University, Faculty of Sciences, P.O. Box 6573, Hadath‑Beirut, Lebanon
| | - Anna Maria Marini
- Laboratory of Membrane Transport Biology, IBMM, Faculty of Sciences, Université Libre de Bruxelles, 6041 Gosselies, Belgium
| | - Roy Khalaf
- Department of Natural Sciences, Lebanese American University, P.O. Box 36, Byblos, Lebanon
| | - Luc Vanhamme
- Laboratory of Molecular Parasitology, Laboratory of Gene Molecular Biology, IBMM, Université Libre de Bruxelles, 6041 Gosselies, Belgium
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El Samad G, Bazzi S, Karam M, Boudjeltia KZ, Vanhamme L, Daher J. Effect of myeloperoxidase modified LDL on bovine and human aortic endothelial cells. Exp Ther Med 2019; 18:4567-4574. [PMID: 31777556 PMCID: PMC6862712 DOI: 10.3892/etm.2019.8109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 04/03/2019] [Accepted: 08/06/2019] [Indexed: 01/01/2023] Open
Abstract
Cardiovascular disease associated with atherosclerosis is a leading cause of death worldwide. Atherosclerosis is primarily caused by the dysfunction of vascular endothelial cells and the subendothelial accumulation of oxidized forms of low-density lipoproteins (LDL). Early observations have associated fibrin deposition with atheroma plaque formation, which has led to the proposition that a decrease in endothelial cell fibrinolysis may negatively influence atherogenesis. It has been recently demonstrated that myeloperoxidase modified LDL (MoxLDL) decreases endothelial cell profibrinolytic capacity in real-time. The present study investigated the role of MoxLDL in endothelial cell dysfunction by determining the molecules that may be involved in decreasing the fibrinolysis of human aortic endothelial cells (HAEC). Accordingly, reverse transcription-quantitative PCR was performed to screen for the differential expression of major genes that are implicated in the fibrinolytic process. In addition, the response of the latter cell type to MoxLDL was compared with bovine aortic endothelial (BAE) cells. Furthermore, the effect of the treatment on the generation of reactive oxygen species (ROS) was also determined. Although the current study did not demonstrate an association between MoxLDL treatment and a change in the expression of any major fibrinolytic factor in HAEC, a discrepancy between HAEC and BAE cells with respect to their response to modified LDL treatment was observed. The result have also demonstrated that MoxLDL does not increase ROS generation in HAEC as opposed to the other major type of modified LDL, cupper oxidized LDL (CuoxLDL) that was reported to exhibit a positive effect at this level. The present study provided important insight into the different effects of MoxLDL and CuoxLDL in endothelial cells, which may aid future studies to determine the various signaling pathways that are promoted by these molecules. The results of the present study may be utilized to identify potential molecular drug targets for the treatment of atherosclerosis.
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Affiliation(s)
- Ghadir El Samad
- Department of Biology, Faculty of Sciences, University of Balamand, Tripoli 100, Lebanon
| | - Samer Bazzi
- Department of Biology, Faculty of Sciences, University of Balamand, Tripoli 100, Lebanon
| | - Marc Karam
- Department of Biology, Faculty of Sciences, University of Balamand, Tripoli 100, Lebanon
| | - Karim Zouaoui Boudjeltia
- Laboratory of Experimental Medicine (ULB 222 Unit), CHU de Charleroi, A. Vésale Hospital, Université Libre de Bruxelles, Montigny-le-Tilleul 6110, Belgium
| | - Luc Vanhamme
- Laboratory of Molecular Biology of Inflammation, IBMM, Faculty of Sciences, Université Libre de Bruxelles, Gosselies 6041, Belgium
| | - Jalil Daher
- Department of Biology, Faculty of Sciences, University of Balamand, Tripoli 100, Lebanon
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Abbas C, Daher J. Pilot study: Post-operative rehabilitation pathway changes and implementation of functional closed kinetic chain exercise in total hip and total knee replacement patient. J Bodyw Mov Ther 2017; 21:823-829. [PMID: 29037634 DOI: 10.1016/j.jbmt.2017.01.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 11/26/2016] [Accepted: 01/12/2017] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The aim of this study was to assess the feasibility of introducing a functional closed kinetic chain exercise program to an acute care setting to reduce length of hospital stay and assess tolerance to exercise immediately following total hip or total knee arthroplasty. METHODS A protocol change implementing a functional closed kinetic chain based exercise program, post total hip (n = 535) and total knee (n = 695) arthroplasty, was performed at Windsor Regional Hospital Ouellette Campus in Windsor, Ontario Canada. A chart review was performed to compare the length of stay, post-surgery, of the new protocol to the length of stay of the previous range of motion and open kinetic chain based protocols of the previous two years. RESULTS A significant (P-value <0.05) number of total hip and total knee arthroplasty patients reduced the length of hospital stay to less than 4 days using the closed kinetic chain program. CONCLUSION Evidence suggests that closed kinetic chain exercises are tolerated in the acute care setting and may be useful in reducing hospital length of stay post total hip and total knee arthroplasty.
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Affiliation(s)
- C Abbas
- Windsor Regional Hospital Ouellette Campus, Windsor, Ontario, Canada
| | - J Daher
- Advanced Wellness Centre, Leamington, Ontario, Canada.
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Chidiac M, Fayyad-Kazan M, Daher J, Poelvoorde P, Bar I, Maenhaut C, Delrée P, Badran B, Vanhamme L. ApolipoproteinL1 is expressed in papillary thyroid carcinomas. Pathol Res Pract 2016; 212:631-5. [DOI: 10.1016/j.prp.2016.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 03/23/2016] [Accepted: 04/13/2016] [Indexed: 12/19/2022]
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Zouaoui Boudjeltia K, Daher J, Van Antwerpen P, Moguilevsky N, Delree P, Ducobu J, Raes M, Badran B, Vanhaeverbeek M, Brohee D, Remacle C, Vanhamme L. Exposure of endothelial cells to physiological levels of myeloperoxidase-modified LDL delays pericellular fibrinolysis. PLoS One 2012; 7:e38810. [PMID: 22723891 PMCID: PMC3378590 DOI: 10.1371/journal.pone.0038810] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 05/14/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Blood fluidity is maintained by a delicate balance between coagulation and fibrinolysis. The endothelial cell surface is a key player in this equilibrium and cell surface disruptions can upset the balance. We investigated the role of pericellular myeloperoxidase oxidized LDLs (Mox-LDLs) in this balance. METHODS AND RESULTS We designed a technical device that enabled us to monitor fibrinolysis in real-time at the surface of an endothelial cell line (EA.hy926), and showed that Mox-LDL decreased pericellular fibrinolysis. There were no changes in fibrinolysis when EA.hy926 endothelial cells were exposed to native LDL (24 hours) at doses of 10, 50, 100 and up to 1250 µg/ml. However, treatment of EA.hy926 endothelial cells with 10 and 50 µg/ml of Mox-LDL (physiological serum concentrations) increased the lysis time by 15 and 13%, respectively (p<0.001), although this effect was not present at higher concentrations of 100 µg/ml. This effect was not correlated with any changes in PAI-1 or t-PA or PA Receptor (PAR) expression. No effect was observed at the surface of smooth muscle cells used as controls. CONCLUSION Our data link the current favorite hypothesis that modified LDL has a causal role in atheroma plaque formation with an old suggestion that fibrin may also play a causal role. Our data help complete the paradigm of atherosclerosis: Modified LDL locally enhances fibrin deposition (present work); fibrin deposits enhance endothelial permeability; this effect allows subendothelial accumulation of lipid and foam cells.
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Affiliation(s)
- Karim Zouaoui Boudjeltia
- Experimental Medicine Laboratory, Université Libre de Bruxelles 222 Unit, CHU Charleroi, A. Vésale, Montigny-Le-Tilleul, Belgium.
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Jordan RB, Daher J, Wasil K. Splints and scar management for acute and reconstructive burn care. Clin Plast Surg 2000; 27:71-85. [PMID: 10665357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Because patients assume a position of comfort during acute burn management, affected joints or regions must be splinted in positions of function to avoid contractures. Particularly with the increasing trend towards ambulatory burn care, close monitoring by the burn team and patient education is required to achieve the best functional result. Despite adequate initial care, contractures sometimes occur, requiring a shift in splinting tactics to correct the deformity. If secondary reconstruction is required, the affected region is once again maintained in the position of function. Although the physiologic mechanism is incompletely defined, pressure therapy to prevent and treat hypertrophic burn scars is an integral component of burn care. Multiple materials and methods are available with treatment, starting soon after burn wound closure, and modified as needed until scar maturation has occurred.
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Affiliation(s)
- R B Jordan
- Department of Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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