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13 results on '"Honma, Koki"'

2. Therapeutic effect of ouabagenin, a novel liver X receptor agonist, on atherosclerosis in nonalcoholic steatohepatitis in SHRSP5/Dmcr rat model

Author

Yamamoto, Shusei, Sato, Ikumi, Fujii, Moe, Kakimoto, Mai, Honma, Koki, Kirihara, Sora, Nakayama, Hinako, Fukuoka, Taketo, Tamura, Satoru, Ueda, Minoru, Hirohata, Satoshi, and Watanabe, Shogo

Subjects
Agonists (Biochemistry) -- Usage -- Health aspects, Fatty liver -- Care and treatment -- Models, Atherosclerosis -- Care and treatment -- Models, Biological sciences
Abstract

The liver X receptor (LXR) can enhance cholesterol transporters, which could remove excess cholesterol from foam cells in atheromas. LXR has two subtypes: LXR[alpha], which aggravates hepatic lipid accumulation, and LXR[beta], which does not. In 2018, ouabagenin (OBG) was reported as a potential LXR[beta]-specific agonist. We aimed to examine whether OBG specifically affects LXR[beta] in nonalcoholic steatohepatitis (NASH); it did not aggravate hepatic steatosis and can suppress the development of atherosclerosis. SHRSP5/Dmcr rats fed a high-fat and high-cholesterol diet were divided into four groups as follows: (I) L-NAME group, (II) L-NAME/OBG group, (III) OBG (-) group, and (IV) OBG (+) group. All groups' rats were intraperitoneally administered L-NAME. The L-NAME/OBG group's rats were intraperitoneally administered OBG and L-NAME simultaneously. After L-NAME administration, the OBG (+) group's rats were administered OBG, while the OBG (- ) group's rats were not. Although all rats developed NASH, OBG did not exacerbate steatosis (L-NAME/OBG and OBG (+) groups). In addition, endothelial cells were protected in the L-NAME/OBG group and foam cells in the atheroma were reduced in the OBG (+) group. OBG is an LXR[beta]-specific agonist and has a potential therapeutic effect on atherosclerosis without developing lipid accumulation in the liver. Key words: nonalcoholic steatohepatitis, atherosclerosis, SHRSP5/Dmcr, ouabagenin, liver X receptor [beta], Shogo Watanabe^orcid.org/0000-0002-1700-2892 1. Introduction Metabolic syndrome (MS) is an increasing health issue in today's society that causes lifestyle diseases, such as hypertension, diabetes, and dyslipidemia. Nonalcoholic fatty liver disease (NAFLD) [...]

Published
2023
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9. Antioxidant action of xanthine oxidase inhibitor febuxostat protects the liver and blood vasculature in SHRSP5/Dmcr rats

Author

Kakimoto, Mai, primary, Fujii, Moe, additional, Sato, Ikumi, additional, Honma, Koki, additional, Nakayama, Hinako, additional, Kirihara, Sora, additional, Fukuoka, Taketo, additional, Ran, Shang, additional, Hirohata, Satoshi, additional, Kitamori, Kazuya, additional, Yamamoto, Shusei, additional, and Watanabe, Shogo, additional

Published
2023
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10. Uric Acid Elevation by Fructose Overload Exacerbates Nash and Atherosclerosis viaOxidative Stress

Author

Fujii, Moe, Kakimoto, Mai, Sato, Ikumi, Honma, Koki, Kirihara, Sora, Nakayama, Hinako, Fukuoka, Taketo, Hirohata, Satoshi, Kitamori, Kazuya, Ran, Shang, Yamamoto, Shusei, and Watanabe, Shogo

Abstract

Background: Nonalcoholic steatohepatitis (NASH) is well associated with an increased risk of cardiovascular disease (CVD), regardless of risk factors for metabolic syndrome. However, intermediary factors between NASH and CVD remain unknown. In recent years, hyperuricemia has been associated not only with gout but also with several other organ diseases, such as hypertension, chronic renal failure, and metabolic syndrome. In addition, hyperuricemia was shown to frequently occur in patients with NASH and could be a risk factor for CVD. Furthermore, serum uric acid (UA) levels have been linked with fructose intake.Objectives: We hypothesized that fructose loading elevates UA levels and exacerbates NASH and atherosclerosis via oxidative stress.Methods: Stroke-prone spontaneously hypertensive rats (SHRSP5/Dmcr), between 14 to 24 weeks of age, were divided into two groups and fed a high-fat and high-cholesterol (HFC) diet. In addition to the HFC diet, the fructose group was subjected to 10% fructose loading. The oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed at 25-week-old, followed by blood sampling, animal sacrifice, endothelial function test, blood biochemistry, histopathological staining, xanthine oxidase activity test, and genetic analysis performed at 26-week-old.Results: Fructose loading increased UA and oxidative stress levels. In addition, fructose loading induced insulin resistance. The fructose group exhibited aggravated hepatic fibrosis and lipid deposition, as well as enhanced lipid accumulation in the mesenteric arteries.Conclusion: In the SHRSP5/Dmcr rat model, elevated UA levels were a risk factor for the exacerbation of NASH and atherosclerosis via oxidative stress.

Published
2024
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11. Ground-based Spectral Measurements of Chlorophyll Fluorescence from Vegetation Canopies

Author

KURIYAMA, Kenji, HONMA, Koki, SHIRAIWA, Tatsuhiko, MANAGO, Naohiro, and KUZE, Hiroaki

Abstract

[ABSTRACT]Detection of vegetation fluorescence is important for understanding physiology of vegetation leaves in relation to photosynthetic activities. We have developed a stand-off system that enables the observation of vegetation fluorescence under both laboratory and field conditions. The intrinsic difficulty in monitoring weak fluorescence signal is the separation between the fluorescence signal around 740 nm and the large reflection of vegetation leaves in the near infrared (NIR) spectral region. In the laboratory measurement, it has been proven that a LED-based light source coupled with cold- or hot- mirrors can provide illumination with only visible or NIR part of the spectrum. The “pure” visible illumination, which is mostly free from the NIR radiation, can lead to the observation of fluorescence signals without hindrance from large NIR reflection. The NIR illumination, on the other hand, enables the evaluation of pure reflectance in NIR free from the fluorescence contribution. The combination of such pieces of spectral information makes it possible to implement the detailed analysis of solar radiation induced fluorescence signals. For field applications, a stand-off measurement system based on an astronomical telescope has been developed to carry out the spectral measurement using a CCD spectrometer, together with the two-dimensional measurement of the fluorescence intensity distribution by means of a cooled CCD camera. A narrow-band optical filter centered at 760 nm, the wavelength of the oxygen A-band, is employed with the CCD camera to exploit the “solar blind” wavelength for the florescence measurement under daylight conditions. We describe the application of the system to a soya-bean field in Kyoto University.

Published
2016

13. Increased Glycine-conjugated and Unconjugated Bile Acid Levels Associated with Aggravation of Nonalcoholic Steatohepatitis and Cardiovascular Disease in SHRSP5/Dmcr Rat.

Author

Yamamoto S, Sato I, Fujii M, Kakimoto M, Honma K, Akiyama N, Sakai M, Fukuhama N, Kumazaki S, Hirohata S, Kitamori K, Yamori Y, and Watanabe S

Subjects
Animals, Rats, Bile Acids and Salts, Glycine, Taurine, Cardiovascular Diseases etiology, Non-alcoholic Fatty Liver Disease
Abstract

The SHRSP5/Dmcr is a useful animal model for the development of nonalcoholic steatohepatitis (NASH) pathology when fed a high-fat, high-cholesterol diet, and further drug interventions can lead to concomitant cardiovascular disease. While SHRSP5/Dmcr rats have been used for basic research related to NASH, details of their bile acid metabolism in this condition are unknown. In this study, we aimed to clarify the changes in the serum bile acid (BA) fractions associated with NASH and found that glycine-conjugated and unconjugated bile acid increased with worsening NASH and cardiovascular disease while taurine-conjugated BA relatively decreased., Competing Interests: No potential conflict of interest relevant to this article was reported.

Published
2023
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