Publications by authors named "Daigo Nakazawa"

53 Publications

Elevated Myeloperoxidase-DNA Complex Levels in Sera of Patients with IgA Vasculitis.

Pathobiology 2021 Nov 23:1-6. Epub 2021 Nov 23.

Department of Dermatology, St. Marianna University School of Medicine, Kawasaki, Japan.

Introduction: IgA vasculitis is a systemic disease that results from the entrapment of circulating IgA-containing immune complexes in small-vessel walls in the skin, kidneys, and gastrointestinal tract. An excessive formation of neutrophil extracellular traps (NETs) is involved in the pathogenesis of vasculitis, especially in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. This study aimed to clarify whether NETs are implicated in IgA vasculitis.

Methods: Twenty-two patients with IgA vasculitis and 4 healthy volunteers were enrolled in this study. Serum levels of myeloperoxidase (MPO)-DNA complex, a fragment derived from NETs, were determined by enzyme-linked immunosorbent assay (ELISA), and the association between MPO-DNA complex levels and clinical parameters was examined. The presence of the ANCA was also assessed by ELISA specific for MPO and proteinase 3 (PR3) and indirect immunofluorescence (IIF), followed by assessing the differences in clinical parameters with and without the ANCA.

Results: Serum MPO-DNA complex levels were significantly higher in patients with IgA vasculitis than those in healthy controls. A significant positive correlation between the serum MPO-DNA complex and IgA levels was noted. Interestingly, 63.6% of IgA vasculitis patients were ANCA-positive in IIF with an atypical pattern, whereas neither MPO-ANCA nor PR3-ANCA was detected by ELISA. These findings indicated that some IgA vasculitis patients possessed the so called minor ANCA. Serum IgA and MPO-DNA complex levels and the frequency of hematuria in the minor ANCA-positive group were significantly higher than in the minor ANCA-negative group.

Conclusion: The collective findings suggested that NETs are certainly involved in the pathogenesis of IgA vasculitis.
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http://dx.doi.org/10.1159/000519869DOI Listing
November 2021

Novel Therapeutic Strategy Based on Neutrophil Subset and Its Function in Autoimmune Disease.

Front Pharmacol 2021 7;12:684886. Epub 2021 Jun 7.

Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.

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http://dx.doi.org/10.3389/fphar.2021.684886DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8215496PMC
June 2021

Being an ADVOCATE for People with ANCA Vasculitis.

Clin J Am Soc Nephrol 2021 10 3;16(10):1581-1583. Epub 2021 Jun 3.

Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.

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http://dx.doi.org/10.2215/CJN.03670321DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8499004PMC
October 2021

Thrombomodulin as a Physiological Modulator of Intravascular Injury.

Front Immunol 2020 16;11:575890. Epub 2020 Sep 16.

Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.

Thrombomodulin (TM), which is predominantly expressed on the endothelium, plays an important role in maintaining vascular homeostasis by regulating the coagulation system. Intravascular injury and inflammation are complicated physiological processes that are induced by injured endothelium-mediated pro-coagulant signaling, necrotic endothelial- and blood cell-derived damage-associated molecular patterns (DAMPs), and DAMP-mediated inflammation. During the hypercoagulable state after endothelial injury, TM is released into the intravascular space by proteolytic cleavage of the endothelium component. Recombinant TM (rTM) is clinically applied to patients with disseminated intravascular coagulation, resulting in protection from tissue injury. Recent studies have revealed that rTM functions as an inflammatory regulator beyond hemostasis through various molecular mechanisms. More specifically, rTM neutralizes DAMPs, including histones and high mobility group box 1 (HMGB1), suppresses excessive activation of the complement system, physiologically protects the endothelium, and influences both innate and acquired immunity. Neutrophil extracellular traps (NETs) promote immunothrombosis by orchestrating platelets to enclose infectious invaders as part of the innate immune system, but excessive immunothrombosis can cause intravascular injury. However, rTM can directly and indirectly regulate NET formation. Furthermore, rTM interacts with mediators of acquired immunity to resolve vascular inflammation. So far, rTM has shown good efficacy in suppressing inflammation in various experimental models, including thrombotic microangiopathy, sterile inflammatory disorders, autoimmune diseases, and sepsis. Thus, rTM has the potential to become a novel tool to regulate intravascular injury via pleiotropic effects.
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http://dx.doi.org/10.3389/fimmu.2020.575890DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7525002PMC
June 2021

Immunothrombosis in severe COVID-19.

EBioMedicine 2020 09 15;59:102942. Epub 2020 Aug 15.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo 060-0812, Japan. Electronic address:

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http://dx.doi.org/10.1016/j.ebiom.2020.102942DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7428773PMC
September 2020

Association of Neutrophil Extracellular Traps with the Development of Idiopathic Osteonecrosis of the Femoral Head.

Am J Pathol 2020 11 21;190(11):2282-2289. Epub 2020 Jul 21.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan. Electronic address:

Idiopathic osteonecrosis of the femoral head (ONFH) is defined as necrosis of osteocytes due to a non-traumatic ischemia of the femoral head. Iatrogenic glucocorticoid administration and habitual alcohol intake are regarded as risk factors. It has been suggested that glucocorticoid-induced activation of platelets contributes to the local blood flow disturbance of the femoral head. Both activated platelets and alcohol can induce neutrophil extracellular traps (NETs). To determine the association of NETs with the development of idiopathic ONFH, surgically resected femoral heads of patients with idiopathic ONFH and osteoarthritis were assessed for existence of NET-forming neutrophils by immunofluorescence staining. NET-forming neutrophils were present in small vessels surrounding the femoral head of patients with idiopathic ONFH but not osteoarthritis. Moreover, Wistar-Kyoto rats were intravenously injected with NET-forming neutrophils or neutrophils without NET induction, and then the ischemic state of the tissue around the femoral head was evaluated by immunohistochemistry for hypoxia-inducible factor-1α. NET-forming neutrophils circulated into the tissue around the femoral head, and hypoxia-inducible factor-1α expression in the tissue was higher compared with that of rats intravenously administered with neutrophils without NET induction. Furthermore, ischemic change of osteocytes was observed in the femoral head of rats given an i.v. injection of NET-forming neutrophils. The collective findings suggest that NETs are possibly associated with the development of idiopathic ONFH.
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http://dx.doi.org/10.1016/j.ajpath.2020.07.008DOI Listing
November 2020

Comparison of the Efficacy and Renal Safety of Bisphosphonate Between Low-Dose/High-Frequency and High-Dose/Low-Frequency Regimens in a Late-Stage Chronic Kidney Disease Rat Model.

Calcif Tissue Int 2020 10 15;107(4):389-402. Epub 2020 Jul 15.

Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.

The efficacy and renal safety of low-dose/high-frequency (LDHF) dosing and high-dose/low-frequency (HDLF) dosing of bisphosphonates (BPs) are comparable in patients with normal kidney function but might be different in patients with late-stage chronic kidney disease (CKD). This study aimed to compare the efficacy and renal safety of two different dosage regimens of a BP, alendronate (ALN), in stage 4 CKD using a rat model. Male, 10-week-old Sprague-Dawley rats were subjected to either 5/6 nephrectomy or sham surgery. The animals received subcutaneous administration of vehicle (daily) or ALN in LDHF dosage regimen (LDHF-ALN: 0.05 mg/kg/day) or HDLF dosage regimen (HDLF-ALN: 0.70 mg/kg/2 weeks). Medications commenced at 20 weeks of age and continued for 10 weeks. Micro-computed tomography, histological analysis, infrared spectroscopic imaging, and serum and urine assays were performed to examine the efficacy and renal safety of the ALN regimens. Both LDHF-ALN and HDLF-ALN increased bone mass, improved micro-structure, and enhanced mechanical properties, without causing further renal impairment in CKD rats. Histologically, however, HDLF-ALN more efficiently suppressed bone turnover, leading to more mineralized trabecular bone, than LDHF-ALN in CKD rats, whereas such differences between LDHF-ALN and HDLF-ALN were not observed in sham rats. Both LDHF-ALN and HDLF-ALN showed therapeutic effects on high bone turnover osteoporosis in CKD stage 4 rats without causing further renal impairment. However, as HDLF-ALN more efficiently suppressed bone turnover than LDHF-ALN in late-stage CKD, HDLF-ALN might be more appropriate than LDHF-ALN for fracture prevention in high bone turnover osteoporosis patients with late-stage CKD.
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http://dx.doi.org/10.1007/s00223-020-00723-1DOI Listing
October 2020

Fluvastatin prevents the development of arthritis in env-pX rats via up-regulation of Rho GTPase-activating protein 12.

Exp Mol Pathol 2020 08 16;115:104454. Epub 2020 May 16.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan. Electronic address:

The pleiotropic effects of statins, including an antiarthritic potential, have been noted. This study aimed to determine the efficacy of statins on rheumatoid arthritis (RA) and clarify how statins affect its pathogenesis. Fluvastatin (500 μg/kg/day) or vehicle was given per os to env-pX rats, which carry the human T-cell leukemia virus type I env-pX gene and spontaneously develop destructive arthritis mimicking RA, for 30 days. Blood sampling and ultrasonography (US) of the ankle joints were conducted on days 0, 10, 20, and 30. On day 30, all rats were euthanized, and the ankle joints were subjected to histological analysis. To clarify how fluvastatin affects the pathogenesis of RA, comprehensive serum exosomal microRNA (miRNA) analysis was performed. Gene expression in the primary culture of synovial fibroblasts derived from arthritic rat and human and non-arthritic rat periarticular tissues was determined quantitatively by real-time reverse transcription-polymerase chain reaction (RT-PCR). As a result, the development of arthritis in env-pX rats was significantly suppressed by fluvastatin, which was evident from the viewpoints of serology, US imaging, and histology. Comprehensive serum exosomal miRNA analysis suggested that the expression of Rho GTPase-activating protein 12 (Arhgap12) was decreased in arthritic env-pX rats but increased with the administration of fluvastatin. Corresponding results were obtained by quantitative RT- PCR using primary culture of synovial fibroblasts. The collective findings suggest that fluvastatin prevents the development of arthritis in env-pX rats via the up-regulation of ARHGAP12. This study suggests that ARHGAP12 can be a possible therapeutic target of RA.
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http://dx.doi.org/10.1016/j.yexmp.2020.104454DOI Listing
August 2020

Incidence and risk of antiresorptive agent-related osteonecrosis of the jaw (ARONJ) after tooth extraction in patients with autoimmune disease.

J Bone Miner Metab 2020 Jul 19;38(4):581-588. Epub 2020 Feb 19.

Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.

Introduction: Antiresorptive agent-related osteonecrosis of the jaw (ARONJ) is a rare but serious complication in patients receiving antiresorprtive agents (AR). However, the incidence of ARONJ after tooth extraction in patients with autoimmune disease (AID) remains unclear. The present study aimed to clarify the high-risk population of ARONJ in patients with AID.

Materials And Methods: The study population comprised 232 patients treated with AR, AID or non-AID, who had undergone dental extraction from January 2011 to September 2017. The incidence and risk factors of ARONJ were analysed retrospectively. Additionally, the relationship between ARONJ and osteoporotic fracture (OF) and AR discontinuation during dental procedures was investigated.

Results: Of 232 patients, 10 developed ARONJ within 1 year of dental extraction. The incidence of ARONJ in patients with AID was higher than that in non-AID patients (2.0/100 person-year vs 0.5/100 person-year; p = 0.03). Among the AID patients, RA patients had strikingly high incidence of ARONJ (3.6/100 person-year). The incidence of neither ARONJ nor OF significantly differed between patients who continued and discontinued AR in the perioperative period.

Conclusion: Patients with AID who undergo dental extraction are at high risk of ARONJ. Discontinuation of AR would not significantly contribute to reduce the incidence of ARONJ in those patients.
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http://dx.doi.org/10.1007/s00774-020-01089-yDOI Listing
July 2020

Relationship between lysosomal-associated membrane protein-2 and anti-phosphatidylserine/prothrombin complex antibody in the pathogenesis of cutaneous vasculitis.

Clin Exp Rheumatol 2020 Mar-Apr;38 Suppl 124(2):161-165. Epub 2020 Jan 27.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

Objectives: We investigated the relationship between lysosomal-associated membrane protein-2 (LAMP-2) and anti-phosphatidylserine/prothrombin (PS/PT) antibody in the pathogenesis of cutaneous vasculitis.

Methods: Cell surface LAMP-2 expression of human neutrophils was measured using flow cytometry. Twenty inbred wild-type Wistar-King-Aptekman-Hokudai (WKAH) rats were divided into four groups: Group 1, rabbit IgG injection only as negative control (n=5); Group 2, both histone and rabbit IgG injection (n=5); Group 3, anti-LAMP-2 antibody injection only (n=5); and Group 4, both histone and anti-LAMP-2 antibody injection (n=5). Ten WKAH rats were divided into two groups: Group A, histone, anti-PS/PT antibody, and anti-LAMP-2 antibody injection (n=5), and Group B, histone, anti-PS/PT antibody, and rabbit IgG injection as control (n=5).

Results: LAMP-2 expression on human neutrophils was induced by cell-free histone exposure in a dose- and time-dependent manner. Histopathological examination revealed the recruitment of neutrophils in cutaneous small vessels in all Group 4 rats. These observations were not evident in systemic organs other than the skin. LAMP-2 expression on the surface of vascular endothelial cells was evident in Group 2, exclusively in the skin, but not in Group 1. Thrombi were detected in various organs in all Groups A and B rats. However, no apparent thrombi were observed in the skin.

Conclusions: Anti-PS/PT and anti-LAMP-2 antibodies are responsible for independent effector mechanisms in the rats given intravenous injection of cell-free histones. We considered that undetermined factors other than cell-free histones could be required for the induction of cutaneous vasculitis by anti-PS/PT and anti-LAMP-2 antibodies.
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September 2020

Recombinant thrombomodulin ameliorates autoimmune vasculitis via immune response regulation and tissue injury protection.

J Autoimmun 2020 03 26;108:102390. Epub 2019 Dec 26.

Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is characterized by necrotizing vasculitis with the presence of pathogenic ANCA. ANCA can potentially cause neutrophil activation and induce neutrophil extracellular traps (NETs), resulting in endothelial damage as well as activation of autoreactive B cells and alternative complement pathway. Recombinant thrombomodulin (rTM) protects the endothelium from vascular injury during disseminated intravascular coagulation, thus we hypothesized that rTM ameliorates necrotizing vasculitis in AAV. In this study, rTM was administered in an experimental AAV rat model. Treatment of experimental AAV rats with rTM improved pulmonary hemorrhage and glomerulonephritis, with a suppression of ANCA production and NETs formation. In addition, in vitro experiments showed that rTM bound to neutrophils via Mac-1 (macrophage-1 antigen) and inhibited ANCA-induced NETs formation accompanied by a suppression of histone citrullination, leading to a protection of the endothelium from NETs toxicity. Additionally, rTM affected lymphocytes leading to the inhibition of pro-inflammatory cytokine/chemokin in PBMC during the antibody production process, which might indirectly be involved in the reduction of pathogenic ANCA. Our data revealed that the rTM could ameliorate autoimmune vasculitis through a combination of different biological mechanisms.
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http://dx.doi.org/10.1016/j.jaut.2019.102390DOI Listing
March 2020

Native myeloperoxidase is required to make the experimental vasculitis model.

Arthritis Res Ther 2019 12 21;21(1):296. Epub 2019 Dec 21.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, 0600812, Japan.

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http://dx.doi.org/10.1186/s13075-019-2084-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925855PMC
December 2019

The Pathogenicity of BPI-ANCA in a Patient With Systemic Vasculitis.

Front Immunol 2019 12;10:1334. Epub 2019 Jun 12.

Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.

ANCA associated vasculitis (AAV) is characterized by systemic necrotizing vasculitis with the presence of ANCA. Although BPI-ANCA is one of the atypical ANCAs and is occasionally seen in patients with vasculitis, the pathogenicity of BPI-ANCA remains unclear. This study was performed to examine the pathogenic role of BPI-ANCA against neutrophils. A 76-year-old Japanese man showed BPI-ANCA positive systemic vasculitis with a medical history of infection. BPI-ANCA IgGs were eluted from the patient serum using an immunoadsorbent column. experiment, healthy donor neutrophils were treated with BPI-AAV IgGs, MPO-AAV IgGs, healthy control IgGs under TNFα stimulation. After 3 h incubation, neutrophil extracellular trap (NET) was assessed by immunofluorescent imaging. To determine the pathogenicity of BPI-ANCA, TNFα-primed neutrophils were incubated with monoclonal BPI-ANCA in the presence or absence of recombinant BPI. BPI-AAV IgGs-treated neutrophils showed NET formation with histone citrullination. Interestingly, the monoclonal BPI-ANCA did not induce NET, but the immune complexes (ICs) of recombinant BPI and BPI-ANCA induced TNFα-dependent NET formation with hypercitrullination. Furthermore, TNFα increased the expression of BPIs in neutrophils and the BPIs were translocated to cell surface. BPI-ANCA could affect neutrophils leading to NET formation and may play a role in the development of systemic vasculitis as pathogenic autoantibody.
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http://dx.doi.org/10.3389/fimmu.2019.01334DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6583233PMC
October 2020

Impact of Weekly Teriparatide on the Bone and Mineral Metabolism in Hemodialysis Patients With Relatively Low Serum Parathyroid Hormone: A Pilot Study.

Ther Apher Dial 2020 Apr 21;24(2):146-153. Epub 2019 Jul 21.

Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.

Adynamic bone disease in HD patients is characterized by skeletal resistance to parathyroid hormone (PTH) or suppression of PTH release, leading to a downregulated bone turnover and bone fracture. Hence, we examined the efficacy of weekly teriparatide for HD patients with low PTH indicating adynamic bone disease without a history of parathyroidectomy. Fifteen HD patients with low PTH were recruited in this prospective observational study. Of them, 10 received teriparatide for 12 months and five nontreated patients were enrolled as control. Primary outcomes were defined as the changes in bone mineral density and bone turnover markers. Bone mineral density at the lumbar spine increased by 3.7% and 2.5% at 6 and 12 months, respectively, and bone formation markers increased, while bone resorption markers did not change in the teriparatide group. At 12 months after teriparatide administration, endogenous PTH was secreted followed by the recovery of low bone turnover. 40% of patients in the teriparatide group dropped out due to adverse events and the most common adverse event was transient hypotension. This study suggests that weekly teriparatide for HD patients with low PTH in the absence of parathyroidectomy accelerates bone formation and bone turnover, leading to increased trabecular bone mass and secretion of endogenous PTH.
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http://dx.doi.org/10.1111/1744-9987.12867DOI Listing
April 2020

Detection of Increased Vascular Signal in Arthritis-Prone Rats Without Joint Swelling Using Superb Microvascular Imaging Ultrasonography.

Ultrasound Med Biol 2019 08 11;45(8):2086-2093. Epub 2019 May 11.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Kita-ku, Sapporo, Japan. Electronic address:

This study aimed to determine whether ultrasonography (US) can detect increased vascular signal in the synovial tissue before overt synovitis in rheumatoid arthritis (RA). Env-pX rats that spontaneously develop RA-like synovitis were used. Ankle joints of 15 pre-morbid env-pX rats were observed with power Doppler and superb microvascular imaging (SMI) using an ultrahigh-frequency (8-24 MHz) probe. Signal values were counted as the number of pixels. The total number of vessels and vessel area in the synovial tissue were histologically evaluated. Dilated vessels were determined from the mean value of synovial vessels in three wild-type rats. In all env-pX rats, apparent synovial proliferation was not observed. However, vasodilation was evident. Only SMI values were significantly correlated with the number of dilated vessels (r = 0.585, p = 0.022) but not with the total number of vessels. US with SMI using ultrahigh-frequency probe can detect increased vascular signal in the synovial tissue of arthritis-prone rats.
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http://dx.doi.org/10.1016/j.ultrasmedbio.2019.04.002DOI Listing
August 2019

A case report dysregulated neutrophil extracellular traps in a patient with propylthiouracil-induced anti-neutrophil cytoplasmic antibody-associated vasculitis.

Medicine (Baltimore) 2019 Apr;98(17):e15328

Department of Rheumatology, Nephrology and Endocrinology, Faculty of Medicine and Graduate School of Medicine.

Rationale: Neutrophil extracellular traps (NETs) are immune defence systems that release extracellular chromatin and myeloid granules including myeloperoxidase (MPO) to kill pathogens. An experimental animal study recently demonstrated that disordered NETs induced by propylthiouracil (PTU) could contribute to the production of MPO anti-neutrophil cytoplasmic antibody (ANCA) and the development of ANCA-associated vasculitis (AAV). However, the role of dysregulated NETs in the pathogenesis of human AAV remains unclear.

Patient Concerns: We report a 19-year-old woman with Graves' disease on PTU presented fever, polyarthralgia, and lung hemorrhage with high titer of MPO-ANCA. This patient had a variety of atypical ANCAs and disordered NETs in vitro.

Diagnoses: A diagnosis of PTU-induced AAV (PTU-AAV).

Interventions: The PTU was discontinued and she was treated with immunosuppressants and plasmapheresis for reducing pathogenic autoantibodies.

Outcomes: Clinical manifestations including fever, polyarthralgia, and lung hemorrhage were on remission with a decrease of dysregulated NETs.

Lessons: The clinical course of this PTU-AAV case indicated that dysregulated NETs would play a role in the development of ANCA and the pathogenesis of AAV.
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http://dx.doi.org/10.1097/MD.0000000000015328DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6831184PMC
April 2019

Pharmaceutical immunoglobulins reduce neutrophil extracellular trap formation and ameliorate the development of MPO-ANCA-associated vasculitis.

Mod Rheumatol 2020 May 12;30(3):544-550. Epub 2019 Apr 12.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

Intravenous immunoglobulin (IVIG) therapy is effective against some autoimmune diseases. We examined the effects of pharmaceutical immunoglobulins on the development of MPO-ANCA-associated vasculitis (MPO-AAV). Peripheral blood neutrophils were pretreated with 5 mg/ml sulfo-immunoglobulins (IVIG-S) and then exposed to 100 nM phorbol myristate acetate (PMA). Thereafter, neutrophil extracellular traps (NETs) were detected by flow cytometry. Next, Wistar-Kyoto rats were given oral administration of 10 mg/kg/day propylthiouracil for 28 days and intraperitoneal (i.p.) injection of 1 μg PMA on days 0 and 7. These rats were divided into two groups: Group 1 with i.p. injection of 400 mg/kg IVIG-S on days 8-12 and Group 2 with vehicle similarly. ANCA titers were chronologically determined by indirect immunofluorescence. On day 28, all rats were killed to examine NET formation in the peritoneum and the development of AAV. IVIG-S significantly inhibited NET formation induced by PMA . NET amounts in the peritoneum in Group 1 were significantly smaller than in Group 2, and ANCA titers in Group 1 were significantly lower than in Group 2. The degree of pulmonary hemorrhage in Group 1 was also smaller than in Group 2. IVIG-S reduce NET formation and ameliorate the development of MPO-AAV.
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http://dx.doi.org/10.1080/14397595.2019.1602292DOI Listing
May 2020

The presence of anti-neutrophil extracellular trap antibody in patients with microscopic polyangiitis.

Rheumatology (Oxford) 2019 07;58(7):1293-1298

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

Objective: Although ANCA is the major autoantibody in patients with ANCA-associated vasculitis, previous studies have suggested the presence of anti-neutrophil extracellular trap (NET) antibody in patients with microscopic polyangiitis (MPA), one type of ANCA-associated vasculitis. In this study, we aimed to determine the prevalence and pathogenic role of anti-NET antibody (ANETA) in MPA.

Methods: We examined the presence or absence of ANETA in sera obtained from 19 MPA patients by indirect immunofluorescence. We compared the clinical parameters, including age, sex, MPO-ANCA, creatinine, CRP, MPO-DNA complexes and vasculitis activity, in ANETA-positive and ANETA-negative MPA patients. We investigated the serum NET induction and degradation abilities of ANETA-positive and ANETA-negative MPA patients with reference to healthy controls (n = 8). Furthermore, we assessed the relationship between ANETA and the effect of IgG depletion on the serum NET degradation ability.

Results: ANETA was present in 10 of the 19 MPA patients. There was no significant difference in the clinical parameters in ANCA-positive and ANCA-negative MPA patients. Although the NET induction ability was higher and the NET degradation ability was lower in MPA sera than those in healthy controls, these abilities were not different between ANETA-positive and ANETA-negative MPA sera. Interestingly, the NET degradation ability in some sera with ANETA was markedly increased by IgG depletion.

Conclusion: Some MPA patients produce ANETA and some ANETA possess an inhibitory function against the serum NET degradation ability. Although further studies are needed, ANETA is worthy of attention in order to understand the pathophysiology of MPA.
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http://dx.doi.org/10.1093/rheumatology/kez089DOI Listing
July 2019

Epitope recognized by anti-glomerular basement membrane (GBM) antibody in a patient with repeated relapse of anti-GBM disease.

Exp Mol Pathol 2019 04 25;107:165-170. Epub 2019 Feb 25.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan. Electronic address:

The major epitopes recognized by autoantibodies in anti-glomerular basement membrane (GBM) disease are found in the α3-subunit non-collagenous domain of type IV collagen [α3(IV)NC1], which is present in the glomerular and alveolar basement membranes. These epitopes are structurally cryptic, owing to the hexamer formation of the non-collagenous domain of α3, α4, and α5 subunits and are expressed by the dissociation of the hexamer. Anti-GBM disease usually manifests as a single attack (SA), and we rarely see patients who repeatedly relapse. We recently treated a patient with anti-GBM disease who exhibited repeated relapse (RR). Here, we conducted immunohistochemistry of formalin-fixed paraffin-embedded normal kidney sections and immunoblotting using recombinant human α3(IV)NC1 to compare the epitopes recognized by anti-GBM antibodies in the RR patient and SA patients. Although a clear staining of GBM especially in the connecting basement membrane of Bowman's capsule was observed when IgGs of SA patients were used as primary antibodies, such staining was not obtained when IgG of the RR patient was employed. In immunoblotting of α3(IV)NC1 using the IgG of the RR patient as a primary antibody, an 18-kDa band was detected besides the 56.8-kDa band corresponding to the whole-size α3(IV)NC1. Whereas the 56.8-kDa band disappeared after digestion of the recombinant α3(IV)NC1 by protease, the 18-kDa band remained. Furthermore, the 18-kDa band was not detected by a commercially available anti-α3(IV)NC1 monoclonal antibody. These findings suggest that the IgG of the RR patient recognizes the epitope distinct from that recognized by the anti-α3(IV)NC1 monoclonal antibody.
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http://dx.doi.org/10.1016/j.yexmp.2019.02.005DOI Listing
April 2019

Formation and Disordered Degradation of Neutrophil Extracellular Traps in Necrotizing Lesions of Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis.

Am J Pathol 2019 04 21;189(4):839-846. Epub 2019 Jan 21.

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan. Electronic address:

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is characterized by the production of ANCAs and systemic necrotizing vasculitis in small vessels. Disordered regulation of neutrophil extracellular traps (NETs) is critically involved in the pathogenesis of AAV. NETs are web-like DNA decorated with antimicrobial proteins; they are extruded from activated neutrophils. The principal degradation factor of NETs in vivo is DNase I; however, NETs resistant to DNase I can persist in tissues and can lead to the production of ANCAs. Deposition of NETs has been demonstrated in glomerular crescents and necrotizing vasculitis in AAV. Here, the amount of NETs in formalin-fixed, paraffin-embedded tissue sections was examined, and the results for AAV were compared with the results for diseases that should be distinguished from AAV. NETs were more abundant in necrotizing vasculitis of AAV than in non-ANCA-associated vasculitis, or in granulomatous angiitis. Pulmonary granulomas in AAV and non-ANCA-associated diseases were further studied. The amount of NETs was significantly greater in necrotizing granulomas of AAV than in granulomas of sarcoidosis without necrosis. Although NETs were formed in necrotizing granulomas of tuberculosis equivalently to those formed in AAV, they were more susceptible to degradation by DNase I than were NETs in AAV. The formation and disordered degradation of NETs in necrotizing lesions are characteristics of AAV and are possibly related to its pathogenesis.
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http://dx.doi.org/10.1016/j.ajpath.2019.01.007DOI Listing
April 2019

Author Correction: Pathogenesis and therapeutic interventions for ANCA-associated vasculitis.

Nat Rev Rheumatol 2019 Feb;15(2):123

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

In the originally published online version of this article there were errors in the Supplementary Information. All three Supplementary Tables had incorrectly numbered references. These errors have now been corrected in the HTML and PDF versions of the manuscript.
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http://dx.doi.org/10.1038/s41584-019-0168-zDOI Listing
February 2019

To NET or not to NET:current opinions and state of the science regarding the formation of neutrophil extracellular traps.

Cell Death Differ 2019 03 8;26(3):395-408. Epub 2019 Jan 8.

Department of Nephrology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.

Since the discovery and definition of neutrophil extracellular traps (NETs) 14 years ago, numerous characteristics and physiological functions of NETs have been uncovered. Nowadays, the field continues to expand and novel mechanisms that orchestrate formation of NETs, their previously unknown properties, and novel implications in disease continue to emerge. The abundance of available data has also led to some confusion in the NET research community due to contradictory results and divergent scientific concepts, such as pro- and anti-inflammatory roles in pathologic conditions, demarcation from other forms of cell death, or the origin of the DNA that forms the NET scaffold. Here, we present prevailing concepts and state of the science in NET-related research and elaborate on open questions and areas of dispute.
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http://dx.doi.org/10.1038/s41418-018-0261-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370810PMC
March 2019

The Diagnostic and Clinical Utility of the Myeloperoxidase-DNA Complex as a Biomarker in Otitis Media With Antineutrophil Cytoplasmic Antibody-associated Vasculitis.

Otol Neurotol 2019 02;40(2):e99-e106

Department of Otolaryngology - Head and Neck Surgery.

Objective: This prospective study aimed to evaluate the diagnostic and clinical utility of the myeloperoxidase (MPO)-DNA complex as a NETosis-derived product in the middle ear fluid of patients with otitis media with antineutrophil cytoplasmic antibody-associated vasculitis (OMAAV).

Study Design: Prospective study.

Setting: Tertiary referral center.

Patients: Twenty-two patients diagnosed with OMAAV.

Intervention: Collection of the fluid samples from middle ear.

Main Outcome Measure: The levels of the MPO-DNA complex in the fluid samples were quantified using an enzyme-linked immunosorbent assay.

Results: Patients with both systemic and localized forms of OMAAV showed significantly higher levels of the MPO-DNA complex compared to the controls (p < 0.001 and p = 0.002, respectively). In particular, they showed significantly higher levels of MPO-DNA complex compared to the controls, regardless of serum antineutrophil cytoplasmic antibody status (p < 0.001 and p < 0.001, respectively) or immunosuppressive therapy (p < 0.001 and p < 0.001, respectively) at the time of sampling. An optical density cutoff value of 0.16 at 405 nm according to the receiver operating characteristic curve showed a sensitivity of 86.4%, specificity of 95.5%, positive predictive value of 95.0% and negative predictive value of 87.5% for the diagnosis of OMAAV. Significant positive correlations were observed between the levels of MPO-DNA complex and the values for air conduction - (r = 0.49, p = 0.022) and bone conduction - pure tone average thresholds (r = 0.45, p = 0.035).

Conclusions: The detection and quantification of the MPO-DNA complex in the otitis media fluid may aid in providing a definite diagnosis as well as predicting the activity and severity of OMAAV.
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http://dx.doi.org/10.1097/MAO.0000000000002081DOI Listing
February 2019

Pathogenesis and therapeutic interventions for ANCA-associated vasculitis.

Nat Rev Rheumatol 2019 02;15(2):91-101

Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) affects systemic small vessels and is accompanied by the presence of ANCAs in the serum. This disease entity includes microscopic polyangiitis, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis and drug-induced AAV. Similar to other autoimmune diseases, AAV develops in patients with a predisposing genetic background who have been exposed to causative environmental factors. The mechanism by which ANCAs cause vasculitis involves ANCA-mediated excessive activation of neutrophils that subsequently release inflammatory cytokines, reactive oxygen species and lytic enzymes. In addition, this excessive activation of neutrophils by ANCAs induces formation of neutrophil extracellular traps (NETs). Although NETs are essential elements in innate immunity, excessive NET formation is harmful to small vessels. Moreover, NETs are involved not only in ANCA-mediated vascular injury but also in the production of ANCAs themselves. Therefore, a vicious cycle of NET formation and ANCA production is considered to be involved in the pathogenesis of AAV. In addition to this role of NETs in AAV, some other important discoveries have been made in the past few years. Incorporating these new insights into our understanding of the pathogenesis of AAV is needed to fully understand and ultimately overcome this disease.
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http://dx.doi.org/10.1038/s41584-018-0145-yDOI Listing
February 2019

Extracellular traps in kidney disease.

Kidney Int 2018 12;94(6):1087-1098

Division of Nephrology, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Germany. Electronic address:

During the past decade the formation of neutrophil extracellular traps (NETs) has been recognized as a unique modality of pathogen fixation (sticky extracellular chromatin) and pathogen killing (cytotoxic histones and proteases) during host defense, as well as collateral tissue damage. Numerous other triggers induce NET formation in multiple forms of sterile inflammation, including thrombosis, gout, obstruction of draining ducts, and trauma. Whether neutrophils always die along with NET release, and if they do die, how, remains under study and is most likely context dependent. In certain settings, neutrophils release NETs while undergoing regulated necrosis-for example, necroptosis. NETs and extracellular traps (ETs) released by macrophages also have been well documented in kidney diseases-for example, in various forms of acute kidney injury. Histones released from ETs and other sources are cytotoxic and elicit inflammation, contributing to necroinflammation of the early-injury phase of acute tubular necrosis in antineutrophil cytoplasmic antibody-related renal vasculitis, anti-glomerular basement membrane disease, lupus nephritis, and thrombotic microangiopathies. Finally, acute kidney injury-related releases of dying renal cells or ETs promote remote organ injuries-for example, acute respiratory distress syndrome. In this review, we summarize what is known about the release of ETs from neutrophils and macrophages in the kidney, the available experimental evidence, and ongoing discussions in the field.
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http://dx.doi.org/10.1016/j.kint.2018.08.035DOI Listing
December 2018

Detection of Autoreactive Type II NKT Cells: A Pilot Study of Comparison Between Healthy Individuals and Patients with Vasculitis.

Cytometry A 2018 11 25;93(11):1157-1164. Epub 2018 Sep 25.

Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.

NKT cells are defined as T cells that recognize hydrophobic antigens presented by class I MHC-like molecules, including CD1d. Among CD1d-restricted NKT cells, type I and type II subsets have been noted. CD1d-restricted type I NKT cells are regarded as pro-inflammatory cells in general. On the contrary, accumulated evidence has demonstrated an anti-inflammatory property of CD1d-restricted type II NKT cells. In our earlier study using a rat model with vasculitis, we demonstrated the pro-inflammatory function of CD1d-restricted type II NKT cells and identified that one such cell recognized P of rat sterol carrier protein 2 (rSCP2 ), which appeared on vascular endothelial cells presented by CD1d. Based on this evidence, we attempted to detect human CD1d-restricted type II NKT cells in peripheral blood using hSCP2 , the human counterpart of rSCP2 together with a CD1d tetramer in flow cytometry. First, we determined the binding of hSCP2 to CD1d. Next, we detected CD3-positive hSCP2 -loaded CD1d (hSCP2 /CD1d) tetramer-binding cells in peripheral blood of healthy donors. The abundance of TGF-β-producing cells rather than TNF-α-producing cells in CD3-positive hSCP2 /CD1d tetramer-binding cells suggests the anti-inflammatory property of SCP2-loaded CD1d (SCP2/CD1d) tetramer-binding type II NKT cells in healthy individuals. Furthermore, we compared cytokine profile between healthy individuals and patients with vasculitis in a pilot study. Interestingly, the percentage of TGF-β-producing cells in SCP2/CD1d tetramer-binding type II NKT cells in vasculitic patients was significantly lower than that in healthy controls despite the greater number of these cells. Although further studies to clarify the mechanism and significance of this phenomenon are needed, SCP2/CD1d tetramer-binding type II NKT cells in peripheral blood should be examined in more detail to understand the pathophysiology of vasculitides in humans. © 2018 International Society for Advancement of Cytometry.
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http://dx.doi.org/10.1002/cyto.a.23618DOI Listing
November 2018

Activated platelets induce MLKL-driven neutrophil necroptosis and release of neutrophil extracellular traps in venous thrombosis.

Cell Death Discov 2018 28;4. Epub 2018 Jun 28.

1Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany.

Venous thromboembolic (VTE) disease, often manifesting as deep vein thrombosis or pulmonary embolism, involves clot formation consisting of blood cells and platelets locked in plasma protein and chromatin networks. The latter derives from neutrophil extracellular traps released by dying neutrophils; however, the molecular mechanisms of neutrophil death in VTE remains unknown. We speculated that mixed lineage kinase-like (MLKL)-driven neutrophil necroptosis contributes to VTE. Indeed, human inferior venous cava thrombus material stained positive for phosphorylated MLKL, the activated version of MLKL that executes necroptotic cell death. In mice, MLKL immunostaining showed co-localization of MLKL with citrullinated histone H3, a marker of neutrophil extracellular trap (NET) formation. These data provide indirect support for a role of MLKL-mediated necroptosis. As a functional proof, both the stabilizer of receptor-interacting protein kinase-1 (RIPK1) and necroptosis inhibitor necrostatin-1s as well as genetic deficiency of MLKL partially prevented clot formation upon inferior vena cava ligation in mice. In both experiments terminal deoxynucleotidyl transferase dUTP nick-end labeling, RIPK3, and citrullinated histone H3+ areas were markedly reduced within the remnant thrombus. In vitro, thrombin-activated platelets induced cell death and NET formation in human neutrophils, which was inhibited by necrostatin-1s treatment. Necrostatin-1s and necrosulfonamide also inhibited neutrophil-platelet aggregate formation induced by tumor necrosis factor-α but had no effect on platelet activation itself. We conclude that in VTE, activated platelets, and possibly other triggers, induce neutrophil necroptosis, a process contributing to clot formation by releasing chromatin in the extracellular space.
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http://dx.doi.org/10.1038/s41420-018-0073-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060161PMC
June 2018

Anti-neutrophil extracellular trap antibody in a patient with relapse of anti-neutrophil cytoplasmic antibody-associated vasculitis: a case report.

BMC Nephrol 2018 06 22;19(1):145. Epub 2018 Jun 22.

Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, 0600812, Japan.

Background: Neutrophil extracellular traps (NETs) are web-like DNA decorated with antimicrobial proteins, such as myeloperoxidase (MPO), which are extruded from activated neutrophils. Although NETs are essential in innate immunity, an excessive formation of NETs has adverse effects, e.g., induction of anti-neutrophil cytoplasmic antibody (ANCA), to the hosts. Since ANCA can induce NET formation in the primed neutrophils, a positive feedback loop can be formed between NETs and ANCA, which is called "ANCA-NETs vicious cycle."

Case Presentation: A 79-year-old Japanese woman developed hydralazine-induced pauci-immune necrotizing crescentic glomerulonephritis with MPO-ANCA. Although the illness improved after cessation of hydralazine, MPO-ANCA-associated vasculitis relapsed 16 months later. Remission was achieved 5 months after beginning of administration of prednisone. In order to determine the involvement of ANCA-NETs vicious cycle in this patient, we examined NET degradation and induction activities in sera obtained at the disease onset (Serum A; MPO-ANCA, 107 IU/ml), at relapse (Serum B; MPO-ANCA, 195 IU/ml), at 3 months after treatment (Serum C; MPO-ANCA, 4.5 IU/ml), and at remission (Serum D; MPO-ANCA, 2.4 IU/ml). NET degradation activity was low in the all sera. NET induction activity was high in Sera A, B, and C but not in D. Additionally, we demonstrated the presence of anti-NET antibody (ANETA) in Sera B and C but not in A or D.

Conclusions: The collective findings suggest NET induction potential of ANETA in the present patient and that the ANETA could contribute to the enhancement of NETs resulting in amplification of the ANCA-NETs vicious cycle.
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http://dx.doi.org/10.1186/s12882-018-0953-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6013953PMC
June 2018

Author Correction: Particles of different sizes and shapes induce neutrophil necroptosis followed by the release of neutrophil extracellular trap-like chromatin.

Sci Rep 2018 Apr 24;8(1):6663. Epub 2018 Apr 24.

Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
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http://dx.doi.org/10.1038/s41598-018-24793-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5915553PMC
April 2018
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