Publications by authors named "Koichi Nishiyama"

Sex differences in the development and progression of cardiovascular disease manifest across multiple life stages. These differences are associated with variations in cardiovascular morphology and function between the sexes. Although estrogens and sex hormones are associated with sex differences in cardiovascular diseases in reproductive adults, the molecular mechanisms of cardiovascular sex differences during development are largely unknown.

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Article Synopsis
  • The study assessed the effectiveness of subcutaneous injection of triamcinolone acetonide (SCTA) in treating eyelid issues (retraction and swelling) in patients with thyroid eye disease (TED), involving 102 patients over a 12-month period.
  • Results showed that SCTA significantly improved eyelid symptoms in 93% of cases, with the majority experiencing reductions in retraction, swelling, and lag; however, some patients required additional injections due to ongoing inflammation.
  • While a single SCTA injection worked for about 60% of patients, further monitoring was recommended, and no serious side effects like elevated intraocular pressure were reported, although some women experienced menstrual disorders.
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Alveologenesis is a spatially coordinated morphogenetic event, during which alveolar myofibroblasts surround the terminal sacs constructed by epithelial cells and endothelial cells (ECs), then contract to form secondary septa to generate alveoli in the lungs. Recent studies have demonstrated the important role of alveolar ECs in this morphogenetic event. However, the mechanisms underlying EC-mediated alveologenesis remain unknown.

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Vascular permeability is dynamically but tightly controlled by vascular endothelial (VE)-cadherin-mediated endothelial cell-cell junctions to maintain homeostasis. Thus, impairments of VE-cadherin-mediated cell adhesions lead to hyperpermeability, promoting the development and progression of various disease processes. Notably, the lungs are a highly vulnerable organ wherein pulmonary inflammation and infection result in vascular leakage.

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  • Blood vessel structure is influenced by mechanical factors like shear stress and biochemical signals from pericytes, which have been examined in lab-created vascular networks.
  • Research using a microfluidic device reveals that sprouts in blood vessels form more often at low shear stress levels (0.5-1.5 dyn cm) and that pericytes help regulate the vessel diameter.
  • Chemotherapy drugs imatinib and crenolanib can decrease pericyte coverage without changing the size of the vessels, enhancing our understanding of vascular development and illustrating the potential of microfluidic devices in future vascular biology and drug research.
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The arachidonic acid cascade is a major inflammatory pathway that produces prostaglandin E (PGE2). Although inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is reported to lead to PGE2 accumulation, the role of 15-PGDH expression in the tumor microenvironment remains unclear. We utilized Panc02 murine pancreatic cancer cells for orthotopic transplantation into wild-type and 15-pgdh mice and found that 15-pgdh depletion in the tumor microenvironment leads to enhanced tumorigenesis accompanied by an increase in cancer-associated fibroblasts (CAFs) and the promotion of fibrosis.

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Angiogenesis is regulated in coordinated fashion by chemical and mechanical cues acting on endothelial cells (ECs). However, the mechanobiological mechanisms of angiogenesis remain unknown. Herein, we demonstrate a crucial role of blood flow-driven intraluminal pressure (IP) in regulating wound angiogenesis.

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Cell signaling and the following gene regulation are tightly regulated to keep homeostasis. NF-κB is a famous key transcription factor for inflammatory cell regulations that obtain a closed feedback loop with IκB. Similarly, we show here, NFAT is also tightly regulated via its downstream target, down syndrome critical region (DSCR)-1.

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Along with blood vessels, lymphatic vessels play an important role in the circulation of body fluid and recruitment of immune cells. Postnatal lymphangiogenesis commonly occurs from preexisting lymphatic vessels by sprouting, which is induced by lymphangiogenic factors such as vascular endothelial growth factor C (VEGF-C). However, the key signals and cell types that stimulate pathological lymphangiogenesis, such as human cystic lymphangioma, are less well known.

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Ketone bodies are generated in the liver and allow for the maintenance of systemic caloric and energy homeostasis during fasting and caloric restriction. It has previously been demonstrated that neonatal ketogenesis is activated independently of starvation. However, the role of ketogenesis during the perinatal period remains unclear.

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A lack of perfusion has been one of the most significant obstacles for three-dimensional culture systems of organoids and embryonic tissues. Here, we developed a simple and reliable method to implement a perfusable capillary network in vitro. The method employed the self-organization of endothelial cells to generate a capillary network and a static pressure difference for culture medium circulation, which can be easily introduced to standard biological laboratories and enables long-term cultivation of vascular structures.

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During angiogenesis, VEGF acts as an attractive cue for endothelial cells (ECs), while Sema3E mediates repulsive cues. Here, we show that the small GTPase RhoJ integrates these opposing signals in directional EC migration. In the GTP-bound state, RhoJ interacts with the cytoplasmic domain of PlexinD1.

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Tumor vasculature creates a hostile tumor microenvironment (TME) in vivo and nourishes cancers, resulting in cancer progression and drug resistance. To mimic the biochemical and biomechanical environments of tumors in vitro, several models integrated with a vascular network have been reported. However, the tumor responses to biochemical and biomechanical stimuli were evaluated under static conditions and failed to incorporate the effects of blood flow to tumors.

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Hypertension is a common noncommunicable disease. According to the World Health Organization, 1.13 billion people were suffering from hypertension in the year 2015.

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A spheroid (a multicellular aggregate) is regarded as a good model of living tissues in the human body. Despite the significant advancement in the spheroid cultures, a perfusable vascular network in the spheroids remains a critical challenge for long-term culture required to maintain and develop their functions, such as protein expressions and morphogenesis. The protocol presents a novel method to integrate a perfusable vascular network within the spheroid in a microfluidic device.

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Background: Collateral arteries provide an alternative blood supply and protect tissues from ischemic damage in patients with peripheral artery disease. However, the mechanism of collateral artery development is difficult to validate.

Methods And Results: Collateral arteries were visualized using micro-x-ray computed tomography.

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Bone morphogenetic protein 9 (BMP9)/BMP10-ALK1 receptor signaling is essential for endothelial differentiation and vascular morphogenesis. Mutations in ALK1/ACVRL1 and other signal-related genes are implicated in human vascular diseases, and the Alk1/Acvrl1 deletion in mice causes severe impairment of vascular formation and embryonic lethality. In the microarray screen to search for novel downstream genes of ALK1 signaling, we found that the mRNA and protein expression of serum/glucocorticoid-regulated kinase 1 (SGK1) was rapidly up-regulated by the BMP9 stimulation of cultured human endothelial cells.

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We studied angiogenesis using mathematical models describing the dynamics of tip cells. We reviewed the basic ideas of angiogenesis models and its numerical simulation technique to produce realistic computer graphics images of sprouting angiogenesis. We examined the classical model of Anderson-Chaplain using fundamental concepts of mass transport and chemical reaction with ECM degradation included.

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Creating vascular networks in tissues is crucial for tissue engineering. Although recent studies have demonstrated the formation of vessel-like structures in a tissue model, long-term culture is still challenging due to the lack of active perfusion in vascular networks. Here, we present a method to create a three-dimensional cellular spheroid with a perfusable vascular network in a microfluidic device.

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Angiogenesis is a multicellular phenomenon driven by morphogenetic cell movements. We recently reported morphogenetic vascular endothelial cell (EC) behaviors to be dynamic and complex. However, the principal mechanisms orchestrating individual EC movements in angiogenic morphogenesis remain largely unknown.

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The origin and developmental mechanisms underlying coronary vessels are not fully elucidated. Here we show that myocardium-derived angiopoietin-1 (Ang1) is essential for coronary vein formation in the developing heart. Cardiomyocyte-specific Ang1 deletion results in defective formation of the subepicardial coronary veins, but had no significant effect on the formation of intramyocardial coronary arteries.

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Endothelin-1 (Edn1), originally identified as a vasoconstrictor peptide, is involved in the development of cranial/cardiac neural crest-derived tissues and organs. In craniofacial development, Edn1 binds to Endothelin type-A receptor (Ednra) to induce homeobox genes Dlx5/Dlx6 and determines the mandibular identity in the first pharyngeal arch. However, it remains unsolved whether this pathway is also critical for pharyngeal arch artery development to form thoracic arteries.

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Objective: Resistin-like molecule (RELM) β is a secretory protein homologous to resistin and reportedly contributes to local immune response regulation in gut and bronchial epithelial cells. However, we found that activated macrophages also express RELMβ and thus investigated the role of RELMβ in the development of atherosclerosis.

Approach And Results: It was demonstrated that foam cells in atherosclerotic lesions of the human coronary artery abundantly express RELMβ.

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