👤 Hiroyuki Kawata

Apolipoprotein A-IV amyloidosis (AApoA-Ⅳ) is a rare subtype of cardiac amyloidosis (CA) and is often overlooked because of its clinical similarity to transthyretin (ATTR) CA. An 82-year-old man presented with heart failure with preserved ejection fraction. His clinical features, including grade 1 uptake on Although the pathologic significance of the unique histologic features remains unclear, they may represent distinguishing characteristics of AApoA-IV amyloidosis. AApoA-IV CA typically presents with elderly-onset heart failure with preserved ejection fraction and may show positive uptake on bone scintigraphy. Differentiation from ATTR CA is possible based on characteristic histopathologic findings and mass spectrometry-based proteomic analysis. Show less

Lymphoplasmacytic lymphoma (LPL) is a type of low-grade B-cell lymphoma, with 90-95% of cases associated with Waldenström macroglobulinemia, characterized by the presence of IgM-type M-protein. We report, for the first time, a case of LPL-producing Bence Jones (BJ) protein kappa. The patient was a 78-year-old woman admitted to our department due to general fatigue and proteinuria that had persisted for 2 months. No M-protein was detected by blood immunofixation, but kappa-type BJ protein was detected in the urine. Light microscopy of a kidney biopsy sample revealed infiltration of lymphocytes and plasma cells into the perirenal adipose tissue and renal interstitium. The infiltrating cells exhibited kappa light chain restriction. Bone marrow examination revealed clusters of immature plasmacytoid lymphocytes that were CD20 positive, CD5 negative, and exhibited light chain restriction. Genetic analysis detected a MYD88 mutation, leading to the diagnosis of LPL in the patient. Six months after starting treatment with tirabrutinib, urinary protein levels improved to 0.2 g/gCr. Renal infiltration was identified due to urinary protein, and currently, no extramedullary lesions outside the kidneys are observed. Tirabrutinib has been extremely effective, but careful follow-up is still required. Show less

The number of patients with non-alcoholic steatohepatitis (NASH) and inflammatory bowel disease (IBD) is increasing. This study elucidates the effect of both NASH and IBD on hepatocellular carcinoma (HCC) using a mouse model combining NASH and IBD. The melanocortin 4 receptor-deficient (Mc4r-KO) mice were divided into four groups with or without a high-fat diet (HFD) and with or without dextran sulfate sodium (DSS) to induce colitis, and the differences in liver damage and occurrence of HCC were analyzed. In the HFD + DSS group, the body weight, liver weight/body weight ratio, and serum levels of albumin and alanine aminotransferase were significantly lower than those in the HFD group. We further found that steatosis was significantly lower and lobular inflammation was significantly higher in the HFD + DSS group than those in the HFD group, and that individual steatosis and lobular inflammation state in the HFD + DSS mice varied. We detected HCC only in the HFD + DSS group, and mice with severe steatosis and mild colitis were found to be at high risk of HCC. Presently, the prediction of HCC is very difficult. In some cases, severe colitis reverses the fat accumulation due to appetite loss. Our findings clearly showed that severe steatohepatitis and mild colitis are simultaneously essential for the occurrence of HCC in patients with NASH and IBD. Show less

We investigated the effect of insulin on the expression of the enhancer of split- and hairy-related protein-2 gene in 3T3-L1 adipocytes and L6 myotubes. The level of enhancer of split- and hairy-related protein-2 mRNA was increased by insulin in both cells. While both wortmannin and LY294002 blocked the increase in 3T3-L1 adipocytes, and only PD98059 was effective in L6 myotubes. Although the increase by insulin in these cells was inhibited by treatment with actinomycin D, this was enhanced by treatment with cycloheximide. Furthermore, cyclic AMP increased the level of enhancer of split- and hairy-related protein-2 mRNA in both cells in an additive manner. Thus, we conclude that insulin and cyclic AMP induce the expression of the enhancer of split- and hairy-related protein-2 gene in both 3T3-L1 adipocytes and L6 myotubes, and that the gene expression enhanced by insulin is regulated by the cell type-specific pathway. The former requires a phosphoinositide 3-kinase pathway and the latter a mitogen-activated protein kinase pathway. Show less

Transcription of the rat fatty acid synthase (FAS) gene in the rat liver can be regulated by feeding a high carbohydrate diet. A carbohydrate response element (ChoRE) located on the rat FAS gene promoter has been identified. Using multiple copies of the ChoRE as the bait in a yeast one-hybrid system, a rat liver cDNA library was screened, and the cDNA of ChoRE-binding proteins was cloned. A positive clone that encodes a basic helix-loop-helix protein, enhancer of split- and hairy-related protein-2 (SHARP-2), was obtained. Northern blot analysis revealed that the levels of SHARP-2 mRNA increase when a high carbohydrate diet is fed to normal rats or when insulin is administered to diabetic rats. In primary cultured rat hepatocytes, insulin rapidly induced an accumulation of SHARP-2 mRNA even in the absence of glucose. A time course for the increase in SHARP-2 mRNA levels indicated that it followed by those of FAS and L-type pyruvate kinase mRNAs and that the initial time course of SHARP-2 mRNA was similar to changes in the levels of glucokinase mRNA and phosphoenolpyruvate carboxykinase mRNA. Although wortmannin, LY294002, and actinomycin D blocked the increase in SHARP-2 mRNA levels by insulin, rapamycin, staurosporine, PD98059, okadaic acid, and 8-bromocyclic AMP had no effect. In addition, nuclear run-on assay revealed that transcription of the rat SHARP-2 gene was induced by insulin. Thus, we conclude that insulin induces the transcription of the rat SHARP-2 gene via a phosphoinositide 3-kinase pathway. Show less