Publications by authors named "Nakajima O"

5-aminolevulinic acid (5-ALA) is an amino acid essential for the synthesis of heme, which is important for various cellular functions, including the mitochondrial electron transport chain. We previously established heterozygous knockout mice (Alas1) for 5-ALA synthase 1 (ALAS1), the rate-limiting enzyme for 5-ALA synthesis, and reported that the mice developed non-obese insulin-resistant diabetes. In the present study, we used these mice to analyze the role of 5-ALA in the immune system.

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The therapeutic effects of oral anticoagulant drugs for nonvalvular atrial fibrillation (NVAF) suggest that the three factor Xa (FXa) inhibitors may have distinct safety profiles, though this is not yet fully conclusive. This study investigated the current dosing of rivaroxaban, apixaban, and edoxaban by monitoring drug plasma concentration (PC) and coagulation activity from the viewpoint of the safety. This multicenter clinical study monitored the drug PC and two coagulation biomarkers (fibrinogen and fibrin monomer complex [FMC]) at peak and trough timing in 268 outpatients taking rivaroxaban (n = 72), apixaban (n = 71), and edoxaban (n = 125) for NVAF.

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Heme serves as a prosthetic group in hemoproteins, including subunits of the mammalian mitochondrial electron transfer chain. The first enzyme in vertebrate heme biosynthesis, 5-aminolevulinic acid synthase 1 (ALAS1), is ubiquitously expressed and essential for producing 5-aminolevulinic acid (ALA). We previously showed that Alas1 heterozygous mice at 20-35 weeks (aged-A1s) manifested impaired glucose metabolism, mitochondrial malformation in skeletal muscle, and reduced exercise tolerance, potentially linked to autophagy dysfunction.

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Heme is an essential component of the hemoproteins involved in the mitochondrial electron transport chain (ETC). Cancer cells have been reported to display high heme levels and increased activity of heme-containing proteins. Consistently, inhibition of heme biosynthesis by the ALAD inhibitor succinylacetone (SA) has been shown to reduce tumor cell survival.

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Article Synopsis
  • Oculocutaneous albinism (OCA) 6 is a genetic condition linked to the SLC24A5 gene, which affects eye color and skin pigmentation, displaying distinct eye symptoms and varied skin pigmentation levels.
  • The study focused on a Japanese patient with OCA6, identifying two genetic variants in the SLC24A5 gene and creating a mouse model to examine the effects of one of these variants.
  • Results showed reduced eumelanin and retinal pigment in the mouse model, along with a significant loss of pigment in the retinal pigment epithelium, highlighting the connection between the genetic mutation and the different severity of eye and skin symptoms.
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Objectives: Cerebral microbleeds (CMBs), which can be detected by gradient-echo T2*-weighted magnetic resonance imaging (MRI), represent small chronic brain hemorrhages caused by structural abnormalities in cerebral small vessels. CMBs are known to be a potential predictor of future stroke, and are associated with age, various cardiovascular risk factors, cognitive impairment, and the use of antithrombotic drugs. Patients with coronary artery disease (CAD) are at potentially high risk of CMBs due to the presence of coexistent conditions.

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Metabolic syndrome results from multiple risk factors that arise from insulin resistance induced by abnormal fat deposition. Chronic inflammation owing to obesity primarily results from the recruitment of pro-inflammatory M1 macrophages into the adipose tissue stroma, as the adipocytes within become hypertrophied. During obesity-induced inflammation in adipose tissue, pro-inflammatory cytokines are produced by macrophages and recruit further pro-inflammatory immune cells into the adipose tissue to boost the immune response.

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L-type amino acid transporter 1 (LAT1) is important for transporting neutral amino acids into cells. LAT1 expression is correlated with cancer malignancy, suggesting that LAT1 is a promising target for cancer therapy. JPH203, a potential novel drug targeting LAT1, has been shown to suppress tumor growth in various cancer cell lines.

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Background: In Japan, both the prevalence of the elderly and super-elderly and those of acute heart failure (AHF) have been increasing rapidly.

Methods: This registry was a prospective multicenter cohort, which enrolled a total of 1253 patients with AHF. In this study, 1117 patients' follow-up data were available and were categorized into three groups according to age: <75 years old (nonelderly), 75-84 years old (elderly), and ≥ 85 years old (super-elderly).

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This study investigated whether combination therapy (CT) with renin-angiotensin system inhibitors and β-blockers improved endpoints in acute heart failure (AHF). AHF patients were recruited to this prospective multicenter cohort study between April 2015 and August 2017. Patients were divided into 3 categories based on ejection fraction (EF), namely heart failure (HF) with reduced EF (HFrEF), HF with midrange EF (HFmrEF), and HF with preserved EF (HFpEF), and a further into 2 groups according to physical status (those who could walk independently outdoors and those who could not).

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Frameshifts in the Calreticulin (CALR) exon 9 provide a recurrent driver mutation of essential thrombocythemia (ET) and primary myelofibrosis among myeloproliferative neoplasms (MPNs). Here, we generated knock-in mice with murine Calr exon 9 mimicking the human CALR mutations, using the CRISPR-Cas9 method. Knock-in mice with del10 [Calr mice] exhibited an ET phenotype with increases of peripheral blood (PB) platelets and leukocytes, and accumulation of megakaryocytes in bone marrow (BM), while those with ins2 (Calr mice) showed a slight splenic enlargement.

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5-Aminolevulinic acid (ALA) is the rate-limiting intermediate in heme biosynthesis in vertebrate species; a reaction catalyzed by the mitochondrial ALA synthase 1 (ALAS1) enzyme. Previously we reported that knockdown of the ubiquitously expressed ALAS1 gene in mice disrupts normal glucose metabolism, attenuates mitochondrial function and results in a prediabetic like phenotype when animals pass 20-weeks of age (Saitoh et al., 2018).

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Home treatment for heart failure (HF) is one of the most important problems in patients after discharge as a secondary preventive measure for rehospitalization for HF. However, there are no detailed studies on gender differences in sociopsychological factors such as living alone for HF rehospitalization among patients with acute HF (AHF).This prospective multicenter cohort study enrolled patients with AHF between April 2015 and August 2017.

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Article Synopsis
  • The study investigates the impact of home- and community-based services on elderly patients with acute heart failure (AHF) in Japan, particularly focusing on those enrolled in long-term care insurance (LTCI).
  • During the one-year follow-up, it found that while there was no significant difference in adverse outcomes for super-elderly patients (≥85 years), elderly patients (<85 years) using these services had a significantly lower rate of hospitalization and mortality after discharge.
  • The results suggest that home and community-based services are beneficial in preventing adverse events for elderly patients with AHF, while their impact on super-elderly patients remains unclear.
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Both heart failure (HF) and chronic obstructive pulmonary disease (COPD) are common diseases, but few studies have assessed the relationship between COPD and outcomes in patients with acute HF, especially in relation to age or ejection fraction (EF). The Kitakawachi Clinical Background and Outcome of Heart Failure Registry was a prospective, multicenter, community-based cohort and enrolled a total of 1,102 patients with acute HF between 2015 and 2017 in this study. The primary endpoint was defined as a composite endpoint that included all-cause mortality and hospitalization for HF.

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Background: In Japan, the long-term care insurance (LTCI) system has an important role in helping elderly people, but there have been no clinical studies that have examined the relationship between the LTCI and prognosis for patients with acute heart failure (HF).

Methods and results: This registry was a prospective multicenter cohort, 1,253 patients were enrolled and 965 patients with acute HF aged ≥65 years were comprised the study group. The composite endpoint included all-cause death and hospitalization for HF after discharge.

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Aims: Aldehyde reductase (AKR1A) is involved in the synthesis of ascorbic acid (AsA) as well as the detoxification of aldehydes. AKR1A (KO) mice produce about 10% of the normal amounts of AsA compared to AKR1A (WT) mice. We investigated physiologic roles of AKR1A in running using the KO mice.

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Our earlier studies demonstrated that cysteine414- (zinc-binding site of mCRY1-) alanine mutant mCRY1 transgenic mice (Tg mice) exhibit diabetes characterized by the reduction of -cell proliferation and by -cell dysfunction, presumably caused by senescence-associated secretory phenotype- (SASP-) like characters of islets. Earlier studies also showed that atypical duct-like structures in the pancreas developed age-dependently in Tg mice. Numerous reports have described that karyopherin alpha 2 (KPNA2) is highly expressed in cancers of different kinds.

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IL-12 is a key cytokine for the promotion of CD4 T cells differentiation to type 1 helper T cells. IL-12 is a heterodimer (IL-12p70) consisting of p40 and p35 subunits, and is mainly secreted from activated antigen-presenting cells, such as macrophages and dendritic cells (DCs). In this study, we found that activated mouse bone marrow-derived DCs (BMDCs) produced a p40 splice variant form mRNA in addition to the conventional p40 mRNA.

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Background: Although activities of daily living (ADL) are recognized as being pertinent in averting relevant readmission of heart failure (HF) and mortality, little research has been conducted to assess a correlation between a decline in ADL and outcomes in HF patients.

Methods: The Kitakawachi Clinical Background and Outcome of Heart Failure Registry is a prospective, multicenter, community-based cohort of HF patients. We categorized the patients into four types of ADL: independent outdoor walking, independent indoor walking, indoor walking with assistance, and abasia.

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Oculocutaneous albinism (OCA) type 4 is one of the most common types of albinism among Japanese population. In some patients who were clinically diagnosed with OCA, we have found a heterozygous pathological mutation in the coding region of SLC45A2, the gene responsible for OCA4, not leading to a DNA-based diagnosis. In this study, we evaluated pathological variants in the promoter region of SLC45A2 in these patients.

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In vertebrates, the initial step in heme biosynthesis is the production of 5-aminolevulinic acid (ALA) by ALA synthase (ALAS). ALA formation is believed to be the rate-limiting step for cellular heme production. Recently, several cohort studies have demonstrated the potential of ALA as a treatment for individuals with prediabetes and type-2 diabetes mellitus.

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Aldehyde reductase (Akr1a) is involved in the synthesis of ascorbic acid (AsA) which may play a role in social behavior. In the current study, we performed analyses on Akr1a-deficient (Akr1a) mice that synthesize about 10% as much AsA as wild-type mice from the viewpoint of intermale aggression. The use of the resident-intruder test revealed that the Akr1a mice exhibited more aggressive phenotypes than wild-type control mice.

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Genome editing has undergone rapid development during the last three years. It is anticipated that genetically modified organisms (GMOs) for food purposes will be widely produced using the clustered regularly interspaced short palindromic repeat/Cas9 (CRISPR)/Cas9 system in the near future. However, the Cas9 gene may then enter the genomes of GMOs for food if the breeding process is not strictly managed, which could lead to the Cas9 protein or associated peptides being produced within these organisms.

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Protoporphyrin IX has been used as an efficient sensitizer in photodynamic diagnosis, photodynamic therapy, and sonodynamic therapy. The level of protoporphyrin IX is very important for diagnostic or therapy effects. 5-aminolevulinic acid synthase 2 (ALAS2) is the key enzyme upstream of protoporphyrin IX synthesis.

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