Publications by authors named "Yun Sang Lee"

Introduction: We investigated the moderating effects of midlife and late-life cognitive activity (CA) on the relationship between tau pathology and both cognition and cognitive decline.

Methods: Eighty-nine non-demented older adults from a Korean cohort underwent comprehensive evaluations, including CA assessments and tau neuroimaging at baseline, and Mini-Mental State Examination (MMSE) at baseline and the 2-year follow-up.

Results: Greater midlife CA was associated with higher MMSE scores in a given amount of tau pathology, whereas higher levels of midlife CA were associated with faster tau-related decline in MMSE scores, particularly in individuals with mild cognitive impairment.

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BackgroundLittle information is yet available for the association between daily water intake, a modifiable lifestyle factor, and Alzheimer's disease (AD) pathology and cerebrovascular injury in the living human brain.ObjectiveOur aim was to explore the correlation between daily fluid intake and in vivo AD pathologies (i.e.

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Objective: We investigated whether the use of antihypertensive medication (AHM) is associated with in vivo Alzheimer's Disease (AD) pathologies in older adults with hypertension and examined if the effect differs by drug-class and blood-brain barrier (BBB) permeability of the drug.

Methods: This cross-sectional study recruited participants from the Korean Brain Aging Study for the Early Diagnosis and Prevention of Alzheimer's Disease. Participants comprised both cognitively normal and impaired older adults diagnosed with hypertension (n = 408).

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Objectives: This study aimed to investigate the efficacy of mitochondrial transplantation as a therapeutic intervention for idiopathic inflammatory myopathy (IIM). This study used a comprehensive approach, incorporating both in vitro and in vivo IIM models, and conducted a first-in-human clinical trial to assess the effectiveness and safety of mitochondria isolated from human umbilical cord mesenchymal stem cells (PN-101).

Methods: Mitochondria isolated from umbilical cord mesenchymal stem cells were designated as PN-101.

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Excessive adipocyte differentiation and accumulation contribute to the development of metabolic disorders. Growth differentiation factor 15 (GDF15) plays an essential role in energy homeostasis and is considered an anti-obesity factor; however, elevated serum levels of endogenous GDF15 have been reported in certain individuals with obesity. In this study, to gain a better understanding of this complex relationship between GDF15 levels and obesity, we investigated GDF15 expression and function during adipogenesis.

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Importance: The neuropathological links underlying the association between changes in liver function and AD have not yet been clearly elucidated.

Objective: We aimed to examine the relationship between liver function markers and longitudinal changes in Alzheimer's disease (AD) core pathologies.

Design: Data from the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease, a longitudinal cohort study initiated in 2014, were utilized.

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Background: Whether telomere length (TL), an indicator of biological ageing, reflects Alzheimer's disease (AD)-related neuropathological change remains unclear. We investigated the relationships between TL, in vivo AD pathologies, including cerebral beta-amyloid and tau deposition, and cognitive outcomes in older adults.

Methods: A total of 458 older adults were included, encompassing both cognitively normal (CN) individuals and those cognitively impaired (CI), with the CI group consisting of individuals with mild cognitive impairment or AD dementia.

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Article Synopsis
  • The study explored the correlation between tau accumulation in the locus coeruleus (LC) and its relationship with tau levels in various cortical regions based on Braak stages, particularly focusing on the influence of amyloid beta (Aβ) deposition.
  • A total of 170 participants underwent advanced imaging techniques, including tau and amyloid PET scans, revealing a significant relationship between LC tau burden and global tau accumulation, especially in individuals with Aβ positivity.
  • While LC tau did not directly affect memory, it was linked to delayed memory through various pathways, highlighting LC tau as a potential indicator for cognitive decline in Alzheimer's disease.
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Introduction: The influence of genetic variation on tau protein aggregation, a key factor in Alzheimer's disease (AD), remains not fully understood. We aimed to identify novel genes associated with brain tau deposition using pathway-based candidate gene association analysis in a Korean cohort.

Methods: We analyzed data for 146 older adults from the well-established Korean AD continuum cohort (Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease; KBASE).

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Objective: Previous studies have reported that vitamin D deficiency increased the risk of Alzheimer's disease (AD) dementia in older adults. However, little is known about how vitamin D is involved in the pathophysiology of AD. Thus, this study aimed to examine the association and interaction of serum vitamin D levels with AD pathologies including cerebral beta-amyloid (Aβ) deposition and neurodegeneration in nondemented older adults.

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Purpose: Accurate clinical staging of potentially resectable pancreatic ductal adenocarcinoma (PDAC) is critical for establishing optimal treatment strategies. While the efficacy of fluorine-18-fluorodeoxyglucose ([F]FDG) positron emission tomography/computed tomography (PET/CT) in clinical staging is unclear, PET/CT detecting fibroblast-activation protein (FAP) expression has recently received considerable attention for detecting various tumors, including PDAC, with high sensitivity. We explored the efficacy of [F]FDG and [F]AIF-FAPI-74 PET/CT in the initial evaluation of potentially resectable PDAC.

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Chronic hypertension leads to injury and fibrosis in major organs. Fibroblast activation protein (FAP) is one of key molecules in tissue fibrosis, and Ga-labeled FAP inhibitor-46 (FAPI46) PET is a recently developed method for evaluating FAP. The aim of this study was to evaluate FAP expression and fibrosis in a hypertension model and to test the feasibility of Ga-FAPI46 PET in hypertension.

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Biodegradable radioactive microspheres labeled with positron emitters hold significant promise for diagnostic and therapeutic applications in cancers and other diseases, including arthritis. The alginate-based polymeric microspheres offer advantages such as biocompatibility, biodegradability, and improved stability, making them suitable for clinical applications. In this study, we developed novel positron emission tomography (PET) microspheres using alginate biopolymer radiolabeled with gallium-68 (Ga) through a straightforward conjugation reaction.

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Background: Clinical trial findings on cholinesterase inhibitors (ChEIs) for mild cognitive impairment (MCI) are inconclusive, offering limited support for their MCI treatment. Given that nearly half of amnestic MCI cases lack cerebral amyloid-β (Aβ) deposition, a hallmark of Alzheimer's disease; this Aβ heterogeneity may explain inconsistent results.

Objective: This study aimed to assess whether Aβ deposition moderates ChEI effects on amnestic MCI cognition.

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Background: Altered thyroid hormone levels have been associated with increased risk of Alzheimer's disease (AD) dementia and related cognitive decline. However, the neuropathological substrates underlying the link between thyroid hormones and AD dementia are not yet fully understood. We first investigated the association between serum thyroid hormone levels and in vivo AD pathologies including both beta-amyloid (Aβ) and tau deposition measured by positron emission tomography (PET).

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Background: Iron oxide nanoparticles (IONPs) have been cleared by the Food and Drug Administration (FDA) for various clinical applications, such as tumor-targeted imaging, hyperthermia therapy, drug delivery, and live-cell tracking. However, the application of IONPs as T1 contrast agents has been restricted due to their high r2 values and r2/r1 ratios, which limit their effectiveness in T1 contrast enhancement. Notably, IONPs with diameters smaller than 5 nm, referred to as extremely small-sized IONPs (ESIONs), have demonstrated potential in overcoming these limitations.

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The epidermal growth factor receptor (EGFR) is an important target for cancer therapies. Many head and neck cancer (HNC) cells have been reported to overexpress EGFR; therefore, anti-EGFR therapies have been attempted in patients with HNC. However, its clinical efficacy is limited owing to the development of drug resistance.

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Importance: In vivo imaging studies of reactive astrocytes are crucial for understanding the pathophysiology of schizophrenia because astrocytes play a critical role in glutamate imbalance and neuroinflammation.

Objective: To investigate in vivo reactive astrocytes in patients with schizophrenia associated with positive symptoms using monoamine oxidase B (MAO-B)-binding fluorine 18 ([18F])-labeled THK5351 positron emission tomography (PET).

Design, Setting, And Participants: In this case-control study, data were collected from October 1, 2021, to January 31, 2023, from the internet advertisement for the healthy control group and from the outpatient clinics of Seoul National University Hospital in Seoul, South Korea, for the schizophrenia group.

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Article Synopsis
  • Low plasma leptin levels are linked to a higher risk of Alzheimer disease and cognitive decline, but the exact mechanisms remain unclear.
  • A longitudinal study analyzed data from 208 cognitively unimpaired older adults to explore the relationship between plasma leptin and brain pathologies related to Alzheimer's, focusing on amyloid-beta and tau deposition.
  • Results showed that lower leptin levels were significantly associated with greater brain amyloid-beta deposition, while no significant link was found between leptin levels and tau deposition in the study cohort.
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Background: Growing evidence suggests that not only cerebrovascular disease but also Alzheimer's disease (AD) pathological process itself cause cerebral white matter degeneration, resulting in white matter hyperintensities (WMHs). Some preclinical evidence also indicates that white matter degeneration may precede or affect the development of AD pathology. This study aimed to clarify the direction of influence between in vivo AD pathologies, particularly beta-amyloid (Aβ) and tau deposition, and WMHs through longitudinal approach.

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Purpose: Mediastinal nodal staging is crucial for surgical candidate selection in non-small cell lung cancer (NSCLC), but conventional imaging has limitations often necessitating invasive staging. We investigated the additive clinical value of fibroblast activation protein inhibitor (FAPI) PET/CT, an imaging technique targeting fibroblast activation protein, for mediastinal nodal staging of NSCLC.

Methods: In this prospective pilot study, we enrolled patients scheduled for surgical resection of NSCLC based on specific criteria designed to align with indications for invasive staging procedures.

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Article Synopsis
  • Researchers developed uniform-sized clodronate-encapsulated liposome nanoplatforms to enhance macrophage depletion for immunotherapy, addressing limitations of previous formulations.
  • The new liposomes were functionalized for targeted delivery and labeled for in vivo imaging, demonstrating stability and effective biodistribution in tests.
  • Among the four types created, the mannosylated liposome showed superior ability to deplete M2 macrophages in both normal liver and tumor settings, indicating its potential as an effective treatment option.
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Inflammasomes are multiprotein complexes involved in the host immune response to pathogen infections. Thus, inflammasomes participate in many conditions, such as acne. Recently, it was shown that NETosis, a type of neutrophil cell death, is induced by bacterial infection and is involved in inflammatory diseases such as delayed wound healing in patients with diabetes.

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Background: Applications of nonthermal plasma have expanded beyond the biomedical field to include antibacterial, anti-inflammatory, wound healing, and tissue regeneration. Plasma enhances epithelial cell repair; however, the potential damage to deep tissues and vascular structures remains under investigation.

Result: This study assessed whether liquid plasma (LP) increased nitric oxide (NO) production in human umbilical vein endothelial cells by modulating endothelial NO synthase (eNOS) phosphorylation and potential signaling pathways.

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Charge ordering (CO), characterized by a periodic modulation of electron density and lattice distortion, has been a fundamental topic in condensed matter physics, serving as a potential platform for inducing novel functional properties. The charge-ordered phase is known to occur in a doped system with high d-electron occupancy, rather than low occupancy. Here, we report the realization of the charge-ordered phase in electron-doped (100) SrTiO epitaxial thin films that have the lowest d-electron occupancy i.

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