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Zununi Vahed S, Rahbar Saadat Y, Ardalan M. Thrombotic microangiopathy during pregnancy. Microvasc Res 2021; 138:104226. [PMID: 34252400 DOI: 10.1016/j.mvr.2021.104226] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/21/2021] [Accepted: 07/08/2021] [Indexed: 10/20/2022]
Abstract
Pregnancy is a high-risk time for the development of different kinds of thrombotic microangiopathy (TMA). Three major syndromes including TTP (thrombotic thrombocytopenic purpura), PE/HELLP (preeclampsia/hemolysis, elevated liver function tests, low platelets), and aHUS (atypical hemolytic- uremic syndrome) should be sought in pregnancy-TMA. These severe disorders share multiple clinical features and overlaps and even the coexistence of more than one pathologic mechanism. Each of these disorders finally ends in endothelial damage and fibrin thrombi formation within the microcirculation that fragments RBCs (schystocytes), aggregates platelets, and creates ischemic injury in the targeted organs i.e.; kidney and brain. Although the mechanisms of these severe disorders have been revealed, pregnancy-related TMA still interfaces with diagnostic and therapeutic challenges. Here, we highlight the current knowledge of diagnosis and management of these complications during pregnancy.
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Kaartinen K, Martola L, Aaltonen S, Meri S. Diagnostic Dilemma of Thrombotic Microangiopathy in Pregnancy. Kidney Int Rep 2020; 6:529-533. [PMID: 33615079 PMCID: PMC7879120 DOI: 10.1016/j.ekir.2020.10.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 10/27/2020] [Indexed: 01/10/2023] Open
Affiliation(s)
- Kati Kaartinen
- Department of Nephrology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Leena Martola
- Department of Nephrology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Sari Aaltonen
- Department of Nephrology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland
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Direct activation of the alternative complement pathway by SARS-CoV-2 spike proteins is blocked by factor D inhibition. Blood 2020; 136:2080-2089. [PMID: 32877502 PMCID: PMC7596849 DOI: 10.1182/blood.2020008248] [Citation(s) in RCA: 247] [Impact Index Per Article: 61.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 08/25/2020] [Indexed: 12/20/2022] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly contagious respiratory virus that can lead to venous/arterial thrombosis, stroke, renal failure, myocardial infarction, thrombocytopenia, and other end-organ damage. Animal models demonstrating end-organ protection in C3-deficient mice and evidence of complement activation in humans have led to the hypothesis that SARS-CoV-2 triggers complement-mediated endothelial damage, but the mechanism is unclear. Here, we demonstrate that the SARS-CoV-2 spike protein (subunit 1 and 2), but not the N protein, directly activates the alternative pathway of complement (APC). Complement-dependent killing using the modified Ham test is blocked by either C5 or factor D inhibition. C3 fragments and C5b-9 are deposited on TF1PIGAnull target cells, and complement factor Bb is increased in the supernatant from spike protein–treated cells. C5 inhibition prevents the accumulation of C5b-9 on cells, but not C3c; however, factor D inhibition prevents both C3c and C5b-9 accumulation. Addition of factor H mitigates the complement attack. In conclusion, SARS-CoV-2 spike proteins convert nonactivator surfaces to activator surfaces by preventing the inactivation of the cell-surface APC convertase. APC activation may explain many of the clinical manifestations (microangiopathy, thrombocytopenia, renal injury, and thrombophilia) of COVID-19 that are also observed in other complement-driven diseases such as atypical hemolytic uremic syndrome and catastrophic antiphospholipid antibody syndrome. C5 inhibition prevents accumulation of C5b-9 in vitro but does not prevent upstream complement activation in response to SARS-CoV-2 spike proteins.
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Yuan X, Yu J, Gerber G, Chaturvedi S, Cole M, Chen H, Metjian A, Sperati CJ, Braunstein EM, Brodsky RA. Ex vivo assays to detect complement activation in complementopathies. Clin Immunol 2020; 221:108616. [PMID: 33148511 DOI: 10.1016/j.clim.2020.108616] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/16/2022]
Abstract
In complement-driven thrombotic microangiopathies, failure to regulate complement activation leads to end-organ damage. The modified Ham (mHam) test measures complement-mediated killing of a nucleated cell in vitro but lacks a confirmatory assay and reliable positive controls. We demonstrate that C5b-9 accumulation on the surface of TF1 PIGAnull cells correlates with cell killing in the mHam. We also show that Sialidase treatment of cells or addition of Shiga toxin 1 to human serum serve as a more reliable positive control for the mHam than cobra venom factor or lipopolysaccharide. Simultaneously performing the mHam and measuring C5b-9 accumulation either in GVB++ or GVB0 MgEGTA buffer with the addition of complement pathway specific inhibitors (anti-C5 antibody or a factor D inhibitor, ACH-145951) can be used to localize defects in complement regulation. As more targeted complement inhibitors become available, these assays may aid in the selection of personalized treatments for patients with complement-mediated diseases.
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Affiliation(s)
- Xuan Yuan
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jia Yu
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Gloria Gerber
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Shruti Chaturvedi
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Michael Cole
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Hang Chen
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Ara Metjian
- Division of Hematology, Department of Medicine, Duke University, Durham, NC, USA
| | - C John Sperati
- Division of Nephrology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Evan M Braunstein
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Robert A Brodsky
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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