Publications by authors named "Manami Iwasaki"

5 Publications

  • Page 1 of 1

A novel enzyme immunoassay for the measurement of plasma (1 → 3)-β-D-glucan levels.

J Immunol Methods 2020 12 29;487:112872. Epub 2020 Sep 29.

Tsukuba Research Institute, Research and Development, Sekisui Medical Co., Ltd., Ibaraki 301-0852, Japan.

The presence of (1 → 3)-β-D-glucan in human plasma is a marker for fungal infections. Currently, the Limulus amebocyte lysate (LAL)-based assay is widely used for the quantification of plasma (1 → 3)-β-D-glucan. However, it has limitations in clinical use, such as an unstable supply of natural resources, complicated manufacturing process, and low-throughput of the reagents. Alternative assays exploiting specific antibodies against (1 → 3)-β-D-glucan have been developed to overcome these challenges. However, these methods are associated with low sensitivity and poorly correlate with the data obtained by the LAL-based assay. The aim of this study is to develop a novel enzyme immunoassay that is as sensitive and accurate in determining plasma (1 → 3)-β-D-glucan levels as compared to that obtained with the LAL-based assay. We generated specific monoclonal antibodies against (1 → 3)-β-D-glucan that recognizes four-unit glucose oligomers with (1 → 3)-β-D-linkages, and constructed a sandwich enzyme-linked immunosorbent assay (ELISA) using these antibodies. The newly developed ELISA showed proportional increase in absorbance with the volume of (1 → 3)-β-D-glucan added. The limit of detection of the assay was 4 pg/ml of plasma (1 → 3)-β-D-glucan that was equivalent to the LAL-based assay and the working range was 4-500 pg/ml. The intra-assay coefficient of variation was 2.2-5.4% using three different concentrations of plasma samples. We observed strong correlation (R = 0.941, slope = 0.986) between the measurements obtained by our ELISA and Fungitec G test ES Nissui, a commonly used LAL-based assay, using 26 types of plasma samples. This could be attributed to the epitopes of the antibodies. Both antibodies could inhibit the LAL-based assay, suggesting that the antibodies recognize the identical regions in β-D-glucan, thereby inactivating factor G, an initiation zymogen for coagulation cascade, in the LAL-based assay. Thus, the ELISA developed in this study can detect fungal infections in clinical settings with similar efficiency as the LAL-based assay. This assay is characterized by good performance, stable supply of materials, and simple manufacturing process and is more suitable for the high-throughput diagnosis of fungal infections.
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December 2020

Protective role of Galectin-7 for skin barrier impairment in atopic dermatitis.

Clin Exp Allergy 2020 08 14;50(8):922-931. Epub 2020 Jun 14.

Department of Dermatology, Hamamatsu University School of Medicine, Hamamatsu, Japan.

Background: Atopic dermatitis (AD) patients have a barrier disorder in association with Th2 dominant skin inflammation. Galectin-7 (Gal-7), a soluble unglycosylated lectin, is highly expressed in the stratum corneum of AD patients. However, the biological significance of increased Gal-7 expression in AD skin lesions remains unclear.

Objective: We aimed to investigate the production mechanism and functional role of Gal-7 in AD patients and IL-4/IL-13-stimulated epidermal keratinocytes.

Methods: We assessed the Gal-7 expression levels in skin lesions and sera from AD patients. Gal-7 levels were also measured in monolayered normal human epidermal keratinocytes (NHEKs) and 3-dimensional (3D)-reconstructed epidermis in the presence or absence of IL-4/IL-13 with or without Stat3, Stat6 or Gal-7 gene silencing.

Results: Gal-7 was highly expressed in the stratum corneum or intercellular space of AD lesional epidermis as assessed by the stratum corneum proteome analysis and immunohistochemistry. A positive correlation was noted between serum Gal-7 level and transepidermal water loss in patients with AD. These clinical findings were corroborated by our in vitro data, which showed that IL-4/IL-13 facilitated the extracellular release of endogenous Gal-7 in both monolayered NHEKs and 3D-reconstructed epidermis. This machinery was caused by IL-4/IL-13-induced cell damage and inhibited by knockdown of Stat6 but not Stat3 in NHEKs. Moreover, we performed Gal-7 knockdown experiment on 3D-reconstructed epidermis and the result suggested that endogenous Gal-7 serves as a protector from IL-4/IL-13-induced disruption of cell-to-cell adhesion and/or cell-to-extracellular matrix adhesion.

Conclusion And Clinical Relevance: Our study unveils the characteristic of Gal-7 and its possible role as an alarmin that reflects the IL-4/IL-13-induced skin barrier impairment in AD.
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August 2020

Decreased expression of suprabasin induces aberrant differentiation and apoptosis of epidermal keratinocytes: Possible role for atopic dermatitis.

J Dermatol Sci 2019 Sep 27;95(3):107-112. Epub 2019 Jul 27.

Department of Dermatology, Hamamatsu University School of Medicine, Hamamatsu, Japan. Electronic address:

Background: Suprabasin (SBSN), a secreted protein, is expressed in various epithelial tissues. The role of SBSN in epidermal differentiation and atopic dermatitis (AD) pathology remains largely unknown.

Objective: To evaluate the effects of SBSN on epidermal keratinocytes and its role in AD.

Methods: We examined the SBSN expression levels in the stratum corneum and the epidermis by proteome analysis and immunohistochemistry, respectively. The serum SBSN concentration was measured by ELISA. These values were compared between AD and healthy control. Morphological changes in the epidermis were investigated in SBSN-knockdown three-dimensional human living skin equivalent (LSE) model with or without IL-4/IL-13.

Results: Epidermal SBSN expression was decreased in AD lesional skin compared to healthy skin, as assessed by the stratum corneum proteome analysis and immunohistochemistry. The SBSN serum levels were significantly lower in AD patients than in normal subjects (P<0.05). The SBSN-deficient LSE exhibited compact stratum corneum, immature stratum granulosum, and increased keratinocyte apoptosis. Th2 cytokines, IL-4 and IL-13, did not affect SBSN expression in LSE. There were no differentiation-associated makers that were affected by the SBSN knockdown. SBSN deficiency-induced apoptosis of keratinocytes was exaggerated by IL-4/IL-13, and accordingly, the addition of recombinant SBSN induced significant keratinocyte proliferation (P<0.05).

Conclusion: Our data demonstrated that SBSN regulates normal epidermal barrier. Th2 cytokines unaffect SBSN expression in keratinocytes, but promote SBSN deficiency-induced apoptosis. It is suggested that SBSN has an anti-apoptotic activity, and its deficiency is involved in the pathogenesis of AD.
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September 2019

Rare Clinical Course of Immunoglobulin G4-Related Inflammatory Abdominal Aortic Aneurysm with Multiple Rare Complications.

Case Rep Vasc Med 2019 3;2019:8249061. Epub 2019 Jun 3.

Department of Cardiovascular Surgery, Hokkaido Medical Center for Child Health and Rehabilitation, Sapporo, Japan.

Immunoglobulin G4- (IgG4-) related inflammatory abdominal aortic aneurysm (AAA) has been recognized as a manifestation of IgG4-related disease (IgG4-RD). We experienced one patient with multiple consecutive manifestations before and after endovascular stent grafting for IgG4-related inflammatory AAA (IAAA). A 71-year-old man was diagnosed with IgG4-RD due to increased IgG4 serum concentration, typical findings of parotid gland biopsy, and periaortitis in another hospital 2 years and 7 months before visiting our hospital. He came to our hospital because of abdominal pain and IAAA. He developed paraplegia after hospitalization and underwent endovascular stent grafting for the IAAA. About one month after stent grafting, he developed perforation of the sigmoid colon due to enteritis. He also had myocardial infarction. Finally, he died of intestinal bleeding. Here, we describe this case with rare, multiple, consecutive manifestations of IgG4-RD, some of which might be caused by IgG4-related IAAA or side effects of treatments rather than by IgG4-RD itself. We report this case because the clinical course seemed rare for IgG4-RD or IgG4-related IAAA. For treating IgG4-RD with IgG4-related IAAA, we should consider factors causing the symptoms and carefully select the proper treatment.
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June 2019

Clonal change of methicillin-resistant Staphylococcus aureus isolated from patients with impetigo in Kagawa, Japan.

J Dermatol 2019 Apr 25;46(4):301-307. Epub 2019 Feb 25.

Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.

Recently, the USA300 clone, which is a Panton-Valentine leukocidin (PVL)-positive clonal complex 8-staphylococcal cassette chromosome mec type IV (CC8-IV) community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strain, emerged in community and hospital settings in Japan. Hence, clonal types of CA-MRSA strains are predicted to be changing. Nonetheless, long-term surveillance of CA-MRSA has not been conducted in Japan. Here, we investigated the transition and current status of CA-MRSA strains isolated from outpatients with impetigo; the samples were collected between 2007 and 2016 in Kagawa, Japan. The detection rate (22.8%, 488/2139 strains) of MRSA slightly decreased in these 10 years. Molecular epidemiological analyses showed that the prevalence of the CC89-II clone, which is a typical CA-MRSA genotype of causative agents of impetigo, significantly decreased from 48.0% (48/100 strains) in 2007-2009 to 21.9% (16/73 strains) in 2013-2016. By contrast, a non-USA300 CC8-IV clone, which is a highly pathogenic CA-MRSA/J clone, significantly increased in prevalence from 9.0% (9/100 strains) to 32.9% (24/73 strains). The prevalence of PVL-positive CA-MRSA strains increased annually from 2012 (0%) to 2015 (6.7%), whereas only one of these strains turned out to be the USA300 clone. Antibiotic susceptibility data revealed that the rates of resistance to gentamicin and clindamycin among CA-MRSA strains decreased along with the decreased prevalence of the CC89-II clone and increased prevalence of the CA-MRSA/J clone. Our data strongly suggest that the clonal types and antibiotic susceptibility of CA-MRSA isolated from patients with impetigo dramatically changed during the last 10 years in Japan.
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April 2019