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Increased BBB permeability contributes to EGCG-caused cognitive function improvement in natural aging rats: pharmacokinetic and distribution analyses. Acta Pharmacol Sin 2019; 40:1490-1500. [PMID: 31092885 DOI: 10.1038/s41401-019-0243-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/25/2019] [Indexed: 12/18/2022] Open
Abstract
Previous studies report that (-)-epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic ingredient in green tea, has high efficacy against Alzheimer's disease (AD) in various in vivo and in vitro models. However, as a water-soluble component, how EGCG exerts its anti-AD effects in the brain was not elucidated. In the present study, we investigated the anti-AD mechanisms of EGCG in natural aging rats with cognitive impairments (CIs) assessed using Morris water maze. The rats were treated with EGCG (100 mg/kg per day, intragastrically) for 4 weeks. The expression of β-amyloid (Aβ1-42) in the brain was detected with immunohistochemical staining. We showed that EGCG administration significantly ameliorated the CI in the aging rats with CI and decreased Aβ1-42 plaque formation in their brains. Then we used an efficient ultra-performance liquid chromatography-tandem mass spectrometer method to evaluate EGCG concentrations in rat plasma and tissue distribution. We found that EGCG absorption was significantly increased in the aging with CI group compared with control young rats. After oral administration of EGCG (100 mg), EGCG could not be detected in the brain tissues of control young rats, but it was found in the brain tissue of aging rats with CI. By using Evans Blue assay, transmission electron microscopy, and Western blotting assay, we demonstrated that the permeability of blood-brain barrier (BBB) was significantly increased in aging rats with CI. These results suggest that the permeability change of BBB is the physiological structural basis for EGCG treatment to improve learning and memory, thus providing a solid evidence for EGCG druggability in anti-AD therapeutic field.
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Adami GR, Tangney CC, Tang JL, Zhou Y, Ghaffari S, Naqib A, Sinha S, Green SJ, Schwartz JL. Effects of green tea on miRNA and microbiome of oral epithelium. Sci Rep 2018; 8:5873. [PMID: 29651001 PMCID: PMC5897334 DOI: 10.1038/s41598-018-22994-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/03/2018] [Indexed: 02/07/2023] Open
Abstract
Consumption of green tea (GT) extracts or purified catechins has shown the ability to prevent oral and other cancers and inhibit cancer progression in rodent models, but the evidence for this in humans is mixed. Working with humans, we sought to understand the source of variable responses to GT by examining its effects on oral epithelium. Lingual epithelial RNA and lingual and gingival microbiota were measured before and after 4 weeks of exposure in tobacco smokers, whom are at high risk of oral cancer. GT consumption had on average inconsistent effects on miRNA expression in the oral epithelium. Only analysis that examined paired miRNAs, showing changed and coordinated expression with GT exposure, provided evidence for a GT effect on miRNAs, identifying miRNAs co-expressed with two hubs, miR-181a-5p and 301a-3p. An examination of the microbiome on cancer prone lingual mucosa, in contrast, showed clear shifts in the relative abundance of Streptococcus and Staphylococcus, and other genera after GT exposure. These data support the idea that tea consumption can consistently change oral bacteria in humans, which may affect carcinogenesis, but argue that GT effects on oral epithelial miRNA expression in humans vary between individuals.
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Affiliation(s)
- Guy R Adami
- Department of Oral Medicine & Diagnostic Sciences, Center for Molecular Biology of Oral Diseases, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL, USA.
| | - Christy C Tangney
- Department of Clinical Nutrition, College of Health Sciences, Rush University Medical Center, 1700 W Van Buren St. Suite 425, Chicago, IL, USA
| | - Jessica L Tang
- Department of Oral Medicine & Diagnostic Sciences, Center for Molecular Biology of Oral Diseases, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL, USA
| | - Yalu Zhou
- Department of Oral Medicine & Diagnostic Sciences, Center for Molecular Biology of Oral Diseases, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL, USA
| | - Saba Ghaffari
- Department of Computer Science and Carl R. Woese Institute of Genomic Biology, University of Illinois at Urbana-Champaign, 2122 Siebel Center, 201N. Goodwin Ave, Urbana, IL, USA
| | - Ankur Naqib
- DNA Services Facility, Research Resources Center, University of Illinois at Chicago, Chicago, IL, USA
| | - Saurabh Sinha
- Department of Computer Science and Carl R. Woese Institute of Genomic Biology, University of Illinois at Urbana-Champaign, 2122 Siebel Center, 201N. Goodwin Ave, Urbana, IL, USA
| | - Stefan J Green
- DNA Services Facility, Research Resources Center, University of Illinois at Chicago, Chicago, IL, USA
| | - Joel L Schwartz
- Department of Oral Medicine & Diagnostic Sciences, Center for Molecular Biology of Oral Diseases, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL, USA
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