• Journal of Ginseng Research
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• v.47 no.1
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• pp.144-154
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• 2023

Background: As the major pathophysiological feature of obstructive sleep apnea (OSA), chronic intermittent hypoxia (CIH) is vital for the occurrence of cardiovascular complications. The activation of calpain-1 mediates the production of endothelial reactive oxygen species (ROS) and impairs nitric oxide (NO) bioavailability, resulting in vascular endothelial dysfunction (VED). Ginsenoside Rg1 is thought to against endothelial cell dysfunction, but the potential mechanism of CIH-induced VED remains unclear. Methods: C57BL/6 mice and human coronary artery endothelial cells (HCAECs) were exposed to CIH following knockout or overexpression of calpain-1. The effect of ginsenoside Rg1 on VED, oxidative stress, mitochondrial dysfunction, and the expression levels of calpain-1, PP2A and p-eNOS were detected both in vivo and in vitro. Results: CIH promoted VED, oxidative stress and mitochondrial dysfunction accompanied by enhanced levels of calpain-1 and PP2A and reduced levels of p-eNOS in mice and cellular levels. Ginsenoside Rg1, calpain-1 knockout, OKA, NAC and TEMPOL treatment protected against CIH-induced VED, oxidative stress and mitochondrial dysfunction, which is likely concomitant with the downregulated protein expression of calpain-1 and PP2A and the upregulation of p-eNOS in mice and cellular levels. Calpain-1 overexpression increased the expression of PP2A, reduced the level of p-eNOS, and accelerated the occurrence and development of VED, oxidative stress and mitochondrial dysfunction in HCAECs exposed to CIH. Moreover, scavengers of O₂^·-, H₂O₂, complex I or mitoKATP abolished CIH-induced impairment in endothelial-dependent relaxation. Conclusion: Ginsenoside Rg1 may alleviate CIH-induced vascular endothelial dysfunction by suppressing the formation of mitochondrial reactive oxygen species through the calpain-1 pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.2
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• pp.177-182
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• 2014

This study was to determine the correlation between endothelial function and neuro-endocrine-immune (NEI) network through observing the changes of NEI network under the different endothelial dysfunction models. Three endothelial dysfunction models were established in male Wistar rats after exposure to homocysteine (Hcy), high fat diet (HFD) and Hcy+HFD. The results showed that there was endothelial dysfunction in all three models with varying degrees. However, the expression of NEI network was totally different. Interestingly, treatment with simvastatin was able to improve vascular endothelial function and restored the imbalance of the NEI network, observed in the Hcy+HFD group. The results indicated that NEI network may have a strong association with endothelial function, and this relationship can be used to distinguish different risk factors and evaluate drug effects.

• Yonsei Medical Journal
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• v.59 no.9
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• pp.1079-1087
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• 2018

Purpose: Obstructive sleep apnea and chronic obstructive pulmonary disease are independent risk factors of cardiovascular disease (CVD), and their coexistence is known as overlap syndrome (OS). Endothelial dysfunction is the initial stage of CVD; however, underlying mechanisms linking OS and CVD are not well understood. The aim of this study was to explore whether OS can lead to more severe inflammation and endothelial apoptosis by promoting endothelial dysfunction, and to assess the intervention effects of antioxidant tempol. Materials and Methods: Male Wistar rats (n=66) were exposed to normal oxygen [normal control (NC) group], intermittent hypoxia (IH group), cigarette smoke (CH group), as well as cigarette smoke and IH (OS group). Tempol intervention was assessed in OS group treated with tempol (OST group) or NaCl (OSN group). After an 8-week challenge, lung tissues, serum, and fresh blood were harvested for analysis of endothelial markers and apoptosis. Results: The levels of intracellular adhesion molecule-1, vascular cellular adhesion molecule-1, and apoptosis in circulating epithelial cells were the highest in OS group and the lowest in NC group. These levels were all greater in IH group than in CH group, and were lower in OST group than in OS and OSN groups (all p<0.001). Conclusion: Synergistic effects of IH with cigarette smoke-induced emphysema produce a greater inflammatory status and endothelial apoptosis. OS-related inflammation and endothelial cell apoptosis may play important roles in promoting cardiovascular dysfunction, and antioxidant tempol could achieve a partial protective effect.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.3
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• pp.231-240
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• 2023

Fabry disease is a lysosomal storage disorder characterized by the lysosomal accumulations of glycosphingolipids in a variety of cytotypes, which include endothelial cells. The disease is inherited and originates from an error in glycosphingolipid catabolism caused by insufficient α-galactosidase A activity, which causes uncontrolled progressive storage of intracellular globotriaosylceramide (Gb3) in the vasculature and extracellular accumulation of lyso-Gb3 (a deacetylated soluble form of Gb3). Necrosis can lead to inflammation, which exacerbates necrosis and creates a positive feedback loop that triggers necroinflammation. However, the role played by necroptosis, a form of programmed necrotic cell death, in the cell-to-cell inflammatory reaction between epithelial and endothelial cells is unclear. Thus, the present study was undertaken to determine whether lyso-Gb3 induces necroptosis and whether necroptosis inhibition protects endothelial dysfunction against lyso-Gb3 inflamed retinal pigment epithelial cells. We found lyso-Gb3 induced necroptosis of a retinal pigment epithelial cell line (ARPE-19) in an autophagy-dependent manner and that conditioned media (CM) from ARPE-19 cells treated with lyso-Gb3 induced the necroptosis, inflammation, and senescence of human umbilical vein endothelial cells. In addition, a pharmacological study showed CM from lyso-Gb3 treated ARPE-19 cells induced endothelial necroptosis, inflammation, and senescence were significantly inhibited by an autophagy inhibitor (3-MA) and by two necroptosis inhibitors (necrostatin and GSK-872), respectively. These results demonstrate lyso-Gb3 induces necroptosis via autophagy and suggest that lyso-Gb3 inflamed retinal pigment epithelial cells trigger endothelial dysfunction via the autophagy-dependent necroptosis pathway. This study suggests the involvement of a novel autophagy-dependent necroptosis pathway in the regulation of endothelial dysfunction in Fabry disease.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.392-395
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• 2008

In an attempt to delineate the direct effect of arsenite-induced endothelial dysfunction on nitric oxide (NO) production, confluent bovine aortic endothelial cells (BAEC) were incubated with arsenite, and endothelial NO synthase expression and NO production were measured. Exposure of arsenite decreased NO production for up to 24h. This decrease was accompanied by decreases in cAMP, protein kinase A (PKA) activity, and furthermore, significant reduction of pCREB. In conclusion, this study is the first to demonstrate that exposure of arsenite decreases NO production by a reduction of pCREB and PKA activity that may be mediated by cAMP, leading to endothelial dysfunction.

• Nutritional Sciences
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• v.9 no.1
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• pp.3-8
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• 2006

Functional damage to microvascular endothelial cells by hyperglycemia is thought to be one of the critical risk factor.; in the impaired wound healing seen with diabetes mellitus. It is also thought that oxidative stress plays a significant role in this endothelial cell dysfunction. The present study examined the differential effects of flavonoids on endothelial cell dysfunction under high glucose conditions. Human endothelial cells exposed to 30 mmol/L glucose for 7 d were pre-treated with various flavonoids and pulse-treated with 0.2 mmol/L $H_2O_2$ for 30 min. High glucose markedly decreased cell viability with elevated oxidant generation and nuclear condensation. $H_2O_2$ insult exacerbated endothelial cytotoxicity due to chronic exposure to high glucose. (-)Epigallocatechin gallate and quercetin improved glucose-induced cell damage with the disappearnnce of apoptotic bodies, whereas apigenin intensified the glucose cytotoxicity. In addition, cell viability data revealed that these flavonoids of (-)epigallocatechin gallate and quercetin substantially attenuated both high glucose- and $H_2O_2$- induced dual endothelial damage. These results suggest that (-)epigallocatechin gallate and quercetin may be beneficial agents for improving endothelial cell dysfunction induced by high glucose and may prevent or reduce the development of diabetic vascular complications.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.95-102
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• 2019

Endoplasmic reticulum (ER) stress is mediated by disturbance of $Ca^{2+}$ homeostasis. The store-operated calcium (SOC) channel is the primary $Ca^{2+}$ channel in non-excitable cells, but its participation in agent-induced ER stress is not clear. In this study, the effects of tunicamycin on $Ca^{2+}$ influx in human umbilical vein endothelial cells (HUVECs) were observed with the fluorescent probe Fluo-4 AM. The effect of tunicamycin on the expression of the unfolded protein response (UPR)-related proteins BiP and CHOP was assayed by western blotting with or without inhibition of Orai1. Tunicamycin induced endothelial dysfunction by activating ER stress. Orai1 expression and the influx of extracellular $Ca^{2+}$ in HUVECs were both upregulated during ER stress. The SOC channel inhibitor SKF96365 reversed tunicamycin-induced endothelial cell dysfunction by inhibiting ER stress. Regulation of tunicamycin-induced ER stress by Orai1 indicates that modification of Orai1 activity may have therapeutic value for conditions with ER stress-induced endothelial dysfunction.

• BMB Reports
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• v.52 no.2
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• pp.145-150
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• 2019

Endothelial dysfunction-induced lipid retention is an early feature of atherosclerotic lesion formation. Apoptosis of vascular smooth muscle cells (VSMCs) is one of the major modulating factors of atherogenesis, which accelerates atherosclerosis progression by causing plaque destabilization and rupture. However, the mechanism underlying VSMC apoptosis mediated by endothelial dysfunction in relation to atherosclerosis remains elusive. In this study, we reveal differential expression of several genes related to lipid retention and apoptosis, in conjunction with atherosclerosis, by utilizing a genetic mouse model of endothelial nitric oxide synthase (eNOS) deficiency manifesting endothelial dysfunction. Moreover, eNOS deficiency led to the enhanced susceptibility against pro-apoptotic insult in VSMCs. In particular, the expression of aggrecan, a major proteoglycan, was elevated in aortic tissue of eNOS deficient mice compared to wild type mice, and administration of aggrecan induced apoptosis in VSMCs. This suggests that eNOS deficiency may elevate aggrecan expression, which promotes apoptosis in VSMC, thereby contributing to atherosclerosis progression. These results may facilitate the development of novel approaches for improving the diagnosis or treatment of atherosclerosis.

• Biomedical Science Letters
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• v.12 no.3
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• pp.255-259
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• 2006

Reactive oxygen species (ROS) is one of the main pathological factors in endothelial disorder. For example, an atherosclerosis is induced by the dysfunction of vascular endothelial cells. The dysfunction of vascular endothelial cells cascades to secrete intercellular adhesion molecule (ICAM)-l substance by ROS. Therefore, The ROS is regraded as an important factor of the injury of vascular endothelial cells and inducement of atherosclerosis. Oxygen radical scavengers playa key role to prevention of many diseases mediated by oxidative stress of ROS. In this study, the toxic effect of ROS on vascular endothelial cells and the effect of antioxidant, vitamin E on bovine pulmonary vascular endothelial cell line (BPVEC) treated with hydrogen peroxide were examined by the colorimetric assay. ROS decreased remarkably cell viability according to the dose- and time-dependent manners. In protective effect of vitamin E on BPVEC treated with hydrogen peroxide, vitamin E increased remarkably cell viability compared with control after BPVEC were treated with $15{\mu}M$ hydrogen peroxide for 6 hours. From these results, it is suggested that ROS has cytotoxicity on cultured BPVEC and oxygen radical scavenger such as vitamin E is very effective in prevention of oxidative stress-induced cytotoxicity.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.5
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• pp.385-392
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• 2013

Vitamin D deficiency is prevalent, primarily due to limited sun exposure, which may be observed in urban areas, or as a result of modern lifestyles. Common myths about vitamin D persist, including that it is mostly obtained from the diet and is only essential for bone and mineral homeostasis. Nonetheless, advances in biomedical science suggest that vitamin D is a hormone that is integral to numerous physiologic functions in most cells and tissues. Therefore, abnormal vitamin D levels may contribute to health disturbances. A number of recent reports on potential associations between vitamin D deficiency and cardiovascular disease have highlighted its role in this system. A focus over the previous decade has been to better understand the mechanisms behind vitamin D regulation and the pathophysiology associated with suboptimal vitamin D levels. Vitamin D deficiency is highly associated with the incidence of cardiovascular diseases, even when considering other well-known risk factors. In this process, the renin-angiotensin system is disrupted, and hypertension and endothelial dysfunction contribute to the risk of cardiovascular disease. Likewise, clinical outcomes upon the normalization of vitamin D levels have been investigated in different patient populations. It makes sense that vitamin D supplementation to improve vitamin D status among vitamin D-deficient individuals could be useful without requiring a sudden lifestyle change. This manuscript provides a brief overview of vitamin D metabolism and the vitamin D receptor. It also summarizes the current clinical research relating to vitamin D supplementation and its effects on hypertension and endothelial dysfunction in cardiovascular medicine.