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Chu KO, Yip YWY, Chan KP, Wang CC, Ng DSC, Pang CP. Amelioration of Functional, Metabolic, and Morphological Deterioration in the Retina following Retinal Detachment by Green Tea Extract. Antioxidants (Basel) 2024; 13:235. [PMID: 38397833 PMCID: PMC10886023 DOI: 10.3390/antiox13020235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
Retinal detachment (RD) can result in the loss of photoreceptors that cause vision impairment and potential blindness. This study explores the protective effects of the oral administration of green tea extract (GTE) in a rat model of RD. Various doses of GTE or epigallocatechin gallate (EGCG), the most active ingredient in green tea catechins, were administered to Sprague Dawley (SD) rats with experimentally induced retinal detachment. The rats received sub-retinal injections of hyaluronic acid (0.1%) to induce RD and were given different doses of GTE and EGCG twice daily for three days. Notably, a low dose of GTE (142.9 mg/kg) caused significantly higher signal amplitudes in electroretinograms (ERGs) compared to higher GTE doses and any doses of EGCG. After administration of a low dose of GTE, the outer nuclear layer thickness, following normalization, of the detached retina reduced to 82.4 ± 8.2% (Mean ± SEM, p < 0.05) of the thickness by RD treatment. This thickness was similar to non-RD conditions, at 83.5 ± 4.7% (Mean ± SEM) of the thickness following RD treatment. In addition, the number of TUNEL-positive cells decreased from 76.7 ± 7.4 to 4.7 ± 1.02 (Mean ± SEM, p < 0.0001). This reduction was associated with the inhibition of apoptosis through decreased sphingomyelin levels and mitigation of oxidative stress shown by a lowered protein carbonyl level, which may involve suppression of HIF-1α pathways. Furthermore, GTE showed anti-inflammatory effects by reducing inflammatory cytokines and increasing resolving cytokines. In conclusion, low-dose GTE, but not EGCG, significantly alleviated RD-induced apoptosis, oxidative stress, inflammation, and energy insufficiency within a short period and without affecting energy metabolism. These findings suggest the potential of low-dose GTE as a protective agent for the retina in RD.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; (K.O.C.); (Y.W.Y.Y.); (K.P.C.)
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, China;
| | - Yolanda Wong Ying Yip
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; (K.O.C.); (Y.W.Y.Y.); (K.P.C.)
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; (K.O.C.); (Y.W.Y.Y.); (K.P.C.)
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, China;
| | - Danny Siu Chun Ng
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; (K.O.C.); (Y.W.Y.Y.); (K.P.C.)
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; (K.O.C.); (Y.W.Y.Y.); (K.P.C.)
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Man GCW, Zheng X, Hung SW, Chan LKY, Zhang T, Chen X, Chu KO, Huen ICY, Lui DWY, Wong AD, Wang CC. Antiviral Effects and Mechanisms of Green Tea Catechins on Influenza: A Perception on Combating Symptoms from COVID-19. Curr Top Med Chem 2024; 24:60-73. [PMID: 38291871 DOI: 10.2174/0115680266251803230925075508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 08/01/2023] [Accepted: 08/18/2023] [Indexed: 02/01/2024]
Abstract
Over the centuries, influenza and its associated epidemics have been a serious public health problem. Although vaccination and medications (such as neuraminidase inhibitors) are the mainstay of pharmacological approaches to prevent and treat influenza, however, frequent mutations in the influenza genome often result in treatment failure and resistance to standard medications which limit their effectiveness. In recent years, green tea catechins have been evaluated as potential anti-influenza agents. Herein, in this review, we highlighted the effects and mechanisms underlying the inhibitory effects of epigallocatechin 3-gallate (EGCG), the most abundant ingredient in green tea, against different influenza viral infections, and their clinical benefits toward prevention and treatment. In addition, as the severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) causes the outbreak of COVID-19 pandemic, our review also delineates the current perspective on SARS-CoV-2 and future insights as to the potential application of EGCG on suppressing the flu-like symptoms caused by COVID-19.
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Affiliation(s)
- Gene Chi Wai Man
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
| | - Xu Zheng
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
| | - Sze Wan Hung
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
| | - Loucia Kit Ying Chan
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
| | - Tao Zhang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
| | - Xiaoyan Chen
- Department of Obstetrics and Gynaecology, Shenzhen Baoan Women's and Children's Hospital, Shenzhen University, Shenzhen, China
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, 4/F, Hong Kong Eye Hospital, 147K, Argyle Street, Mongkok, Kowloon, Hong Kong
| | - Ian Chung Yuen Huen
- Aptorum Therapeutics Limited, Unit 232 Building 12W, Hong Kong Science Park, N.T. Hong Kong
| | - Darren Wang Yip Lui
- Aptorum Therapeutics Limited, Unit 232 Building 12W, Hong Kong Science Park, N.T. Hong Kong
| | - Alfred Ding Wong
- Luk Yu Teabags, Multipak Limited, 4th floor, Primoknit Industrial Building, 7-9 Kung Yip Street, Kwai Chung, N.T., Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
- Li Ka Shing Institute of Health Sciences and School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
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Ng TK, Chu KO, Wang CC, Pang CP. Green Tea Catechins as Therapeutic Antioxidants for Glaucoma Treatment. Antioxidants (Basel) 2023; 12:1320. [PMID: 37507860 PMCID: PMC10376590 DOI: 10.3390/antiox12071320] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/02/2023] [Accepted: 06/09/2023] [Indexed: 07/30/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness and visual impairment, affecting more than 80 million individuals worldwide. Oxidative stress and inflammation-induced neurodegenerative insults to retinal ganglion cells are the main pathogenesis of glaucoma. Retinal ganglion cells, the retinal neurons transmitting the visual signals to the visual cortex in the brain, have very limited regeneration or recovery capacity after damages. Apart from intraocular pressure-lowering treatments, there is still no clinically effective treatment to rescue the degeneration of retinal ganglion cells in glaucoma. Dietary antioxidants are easily accessible and can be applied as supplements assisting in the clinical treatments. Catechins, a chemical family of flavonoids, are the phenolic compounds found in many plants, especially in green tea. The anti-oxidative and anti-inflammatory properties of green tea catechins in vitro and in vivo have been well proven. They could be a potential treatment ameliorating retinal ganglion cell degeneration in glaucoma. In this review, the chemistry, pharmacokinetics, and therapeutic properties of green tea catechins were summarized. Research updates on the biological effects of green tea catechins in cellular and animal experimental glaucoma models were reviewed. In addition, clinical potentials of green tea catechins for glaucoma treatment were also highlighted.
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Affiliation(s)
- Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong
| | - Chi Pui Pang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
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Chu KO, Man GCW, Hung SW, Chan TH, Lee WYT, Chan KP, Pang CP, Wang CC. Determination of (-)-epigallocatechin-3-gallate octaacetate and its metabolites in plasma of rats for pharmacokinetic study by ultra-performance-liquid-chromatography coupled to quadrupole-time-of-flight-mass-spectrometry. Front Pharmacol 2022; 13:1025053. [PMID: 36304154 PMCID: PMC9592989 DOI: 10.3389/fphar.2022.1025053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 09/22/2022] [Indexed: 11/13/2022] Open
Abstract
(-)-Epigallocatechin-gallate octaacetate (pro-EGCG), a prodrug of epigallocatechin-gallate (EGCG), has been used for pre-clinical study for the treatment of endometriosis. A validated analytical method has been developed for the determination of plasma pro-EGCG and its metabolites after oral administration using ultra-performance-liquid-chromatography coupled to quadrupole-time-of-flight-mass-spectrometry (UPLC-Qtof-MS). This method is more robust, rapid, sensitive, simpler, and able to detect pro-EGCG metabolites compared to our previous method. Pro-EGCG in the plasma was stabilized from rapid degradation by formic acid, extracted by isopropanol/methyl-tert-butyl ether mixture, separated by UPLC core column, and quantified by an exact mass method with Qtof-MS. The lower limit of quantification (LLOQ), intra-day and inter-day precision, and accuracy for the range of 0.01–2.5 μg/mL were within acceptable limits. The sensitivity was improved by 25 folds using pro-EGCG ammonium adduct [M + NH4]+. This is the first report on the pharmacokinetics of oral administration with maximum-concentration (Cmax) was 0.067 ± 0.04 μg/mL, time-of-maximum-concentration (Tmax) was 1.33 h, area-under-curve (AUC) was 0.20 ± 0.05 h × µg/mL, and elimination-rate was 0.20 ± 0.11 hr−1. The pharmacokinetic profiles of pro-EGCG metabolites, (-)-epigallocatechin-gallate (EGCG) diacetates and EGCG triacetates, were also presented. This method is robust, rapid, and sensitive for the pharmacokinetic study of pro-EGCG and metabolites.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Shatin, China
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, China
| | - Gene Chi Wai Man
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, China
| | - Sze Wan Hung
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, China
| | - Tak Hang Chan
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
- Department of Chemistry, McGill University, Montreal, QC, Canada
| | | | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Shatin, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Shatin, China
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, China
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, China
- Li Ka Shing Institute of Health Sciences; and School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, China
- *Correspondence: Chi Chiu Wang,
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Chu KO, Chan TI, Chan KP, Yip YW, Bakthavatsalam M, Wang CC, Pang CP, Brelen ME. Untargeted metabolomic analysis of aqueous humor in diabetic macular edema. Mol Vis 2022; 28:230-244. [PMID: 36284671 PMCID: PMC9514551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 08/17/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The mechanism of diabetic macular edema (DME) was explored by comparing the intraocular metabolite profiles of the aqueous humor of patients with DME to those of diabetic patients without DME using untargeted metabolomic analysis. METHODS Aqueous samples from 18 type 2 diabetic patients with DME and 18 type 2 diabetic patients without DME used as controls were analyzed using liquid chromatography-mass spectrometry (LCMS). The two groups of patients were age and gender matched and had no systemic diseases other than diabetes mellitus (DM). The metabolites were analyzed using orthogonal partial least square discriminant analysis. RESULTS The metabolite profiles in DME patients differed from those in DM controls. This indicates the following metabolic derangements in DME: (a) a higher amount of oxidized fatty acids but a lower amount of endogenous antioxidants (oxidative stress); (b) higher levels of β-glucose and homocysteine but a lower level of sorbitol (hyperglycemia); (c) a higher amount of prostaglandin metabolites (inflammation); (d) higher amounts of acylcarnitines, odd-numbered fatty acids, and 7,8-diaminononanoate (respiration deterioration); (e) a higher amount of neurotransmitter metabolites and homovanillic acid (neuronal damage); (f) a lower amount of extracellular matrix (ECM) constituents (ECM deterioration); and (g) a higher amount of di-amino peptides (microvascular damage). CONCLUSIONS The change in the metabolic profiles in the aqueous humor of DME patients compared to DM controls without DME indicates that DME patients may have less capability to resist various stresses or damaging pathological conditions, such as oxidative stress, mitochondrial insufficiency, inflammation, and ECM deterioration.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong,Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong
| | - Tina InLam Chan
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Yolanda WongYing Yip
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Malini Bakthavatsalam
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong,Li Ka Shing Institute of Health Science, the Chinese University of Hong Kong,School of Biomedical Sciences, the Chinese University of Hong Kong
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Marten E. Brelen
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
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Chu KO, Chan KP, Yip YWY, Chu WK, Wang C, Pang CP. Systemic and Ocular Anti-Inflammatory Mechanisms of Green Tea Extract on Endotoxin-Induced Ocular Inflammation. Front Endocrinol (Lausanne) 2022; 13:899271. [PMID: 35909558 PMCID: PMC9335207 DOI: 10.3389/fendo.2022.899271] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Green tea extract (GTE) alleviated ocular inflammations in endotoxin-induced uveitis (EIU) rat model induced by lipopolysaccharide (LPS) but the underlying mechanism is unclear. Objectives To investigate the systematic and local mechanisms of the alleviation by untargeted metabolomics using liquid chromatography-tandem mass spectrometry. Methods Sprague-Dawley rats were divided into control group, LPS treatment group, and LPS treatment group treated with GTE two hours after LPS injection. The eyes were monitored by slip lamp and electroretinography examination after 24 hours. The plasma and retina were collected for metabolomics analysis. Results In LPS treated rats, the iris showed hyperemia. Plasma prostaglandins, arachidonic acids, corticosteroid metabolites, and bile acid metabolites increased. In the retina, histamine antagonists, corticosteroids, membrane phospholipids, free antioxidants, and sugars also increased but fatty acid metabolites, N-acetylglucosamine-6-sulphate, pyrocatechol, and adipic acid decreased. After GTE treatment, the a- and b- waves of electroretinography increased by 13%. Plasma phosphorylcholine lipids increased but plasma prostaglandin E1, cholanic metabolites, and glutarylglycine decreased. In the retina, tetranor-PGAM, pantothenic derivatives, 2-ethylacylcarinitine, and kynuramine levels decreased but anti-oxidative seleno-peptide level increased. Only phospholipids, fatty acids, and arachidonic acid metabolites in plasma and in the retina had significant correlation (p < 0.05, r > 0.4 or r < -0.4). Conclusions The results showed GTE indirectly induced systemic phosphorylcholine lipids to suppress inflammatory responses, hepatic damage, and respiratory mitochondrial stress in EIU rats induced by LPS. Phospholipids may be a therapeutic target of GTE for anterior chamber inflammation.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Yolanda Wong Ying Yip
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Li Ka Shing Institute of Health Science, the Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
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Hung SW, Li Y, Chen X, Chu KO, Zhao Y, Liu Y, Guo X, Man GCW, Wang CC. Green Tea Epigallocatechin-3-Gallate Regulates Autophagy in Male and Female Reproductive Cancer. Front Pharmacol 2022; 13:906746. [PMID: 35860020 PMCID: PMC9289441 DOI: 10.3389/fphar.2022.906746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/17/2022] [Indexed: 11/29/2022] Open
Abstract
With a rich abundance of natural polyphenols, green tea has become one of the most popular and healthiest nonalcoholic beverages being consumed worldwide. Epigallocatechin-3-gallate (EGCG) is the predominant catechin found in green tea, which has been shown to promote numerous health benefits, including metabolic regulation, antioxidant, anti-inflammatory, and anticancer. Clinical studies have also shown the inhibitory effects of EGCG on cancers of the male and female reproductive system, including ovarian, cervical, endometrial, breast, testicular, and prostate cancers. Autophagy is a natural, self-degradation process that serves important functions in both tumor suppression and tumor cell survival. Naturally derived products have the potential to be an effective and safe alternative in balancing autophagy and maintaining homeostasis during tumor development. Although EGCG has been shown to play a critical role in the suppression of multiple cancers, its role as autophagy modulator in cancers of the male and female reproductive system remains to be fully discussed. Herein, we aim to provide an overview of the current knowledge of EGCG in targeting autophagy and its related signaling mechanism in reproductive cancers. Effects of EGCG on regulating autophagy toward reproductive cancers as a single therapy or cotreatment with other chemotherapies will be reviewed and compared. Additionally, the underlying mechanisms and crosstalk of EGCG between autophagy and other cellular processes, such as reactive oxidative stress, ER stress, angiogenesis, and apoptosis, will be summarized. The present review will help to shed light on the significance of green tea as a potential therapeutic treatment for reproductive cancers through regulating autophagy.
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Affiliation(s)
- Sze Wan Hung
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Yiran Li
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoyan Chen
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- Department of Obstetrics and Gynaecology, Shenzhen Baoan Women’s and Children’s Hospital, Shenzhen University, Shenzhen, China
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, Hong Kong Eye Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Yiwei Zhao
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- Department of Obstetrics and Gynecology, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yingyu Liu
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- Department of Obstetrics and Gynaecology, Shenzhen Baoan Women’s and Children’s Hospital, Shenzhen University, Shenzhen, China
| | - Xi Guo
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Gene Chi-Wai Man
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- Department of Orthopaedics and Traumatology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- *Correspondence: Gene Chi-Wai Man, ; Chi Chiu Wang,
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- Li Ka Shing Institute of Health Sciences; School of Biomedical Sciences; and Chinese University of Hong Kong-Sichuan University Joint Laboratory in Reproductive Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
- *Correspondence: Gene Chi-Wai Man, ; Chi Chiu Wang,
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Li J, Du L, He JN, Chu KO, Guo CL, Wong MOM, Pang CP, Chu WK. Anti-inflammatory Effects of GTE in Eye Diseases. Front Nutr 2021; 8:753955. [PMID: 34966770 PMCID: PMC8711650 DOI: 10.3389/fnut.2021.753955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ocular inflammation is a common complication of various eye diseases with wide consequences from irritations to potentially sight-threatening complications. Green tea is a popular beverage throughout the world. One of the proven health benefits of consuming green tea extract (GTE) is anti-inflammation. Catechins are the biologically active constituents of GTE. In in vitro and in vivo studies, GTE and catechins present inhibition of inflammatory responses in the development of ocular inflammation including infectious, non-infectious or autoimmune, and oxidative-induced complications. Research on the ocular inflammation in animal models has made significant progress in the past decades and several key disease mechanisms have been identified. Here we review the experimental investigations on the effects of GTE and catechins on various ocular inflammation related diseases including glaucoma, age-related macular degeneration, uveitis and ocular surface inflammation. We also review the pharmacokinetics of GTE constituents and safety of green tea consumption. We discuss the insights and perspectives of these experimental results, which would be useful for future development of novel therapeutics in human.
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Affiliation(s)
- Jian Li
- Department of Ophthalmology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Lin Du
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Jing Na He
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Cosmos Liutao Guo
- Bachelor of Medicine and Bachelor of Surgery Programme, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Mandy Oi Man Wong
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China.,Hong Kong Eye Hospital, Hong Kong, Hong Kong SAR, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
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Chu KO, Chan KP, Chan SO, Ng TK, Jhanji V, Wang CC, Pang CP. Metabolomics of Green-Tea Catechins on Vascular-Endothelial-Growth-Factor-Stimulated Human-Endothelial-Cell Survival. J Agric Food Chem 2018; 66:12866-12875. [PMID: 30406651 DOI: 10.1021/acs.jafc.8b05998] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Neovascularization causes serious oculopathy related to upregulation of vascular-endothelial-growth factor (VEGF) causing new capillary growth via endothelial cells. Green-tea-extract (GTE) constituents possess antiangiogenesis properties. We used VEGF to induce human umbilical-vein endothelial cells (HUVECs) and applied GTE, epigallocatechin gallate (EGCG), and mixtures of different compositions of purified catechins (M1 and M2) to evaluate their efficacies of inhibition and their underlying mechanisms using cell-cycle analysis and untargeted metabolomics techniques. GTE, EGCG, M1, and M2 induced HUVEC apoptosis by 22.1 ± 2, 20.0 ± 0.7, 50.7 ± 8.5, and 69.8 ± 4.1%, respectively. GTE exerted a broad, balanced metabolomics spectrum, involving suppression of the biosynthesis of cellular building blocks and oxidative-phosphorylation metabolites as well as promotion of the biosynthesis of membrane lipids and growth factors. M2 mainly induced mechanisms associated with energy and biosynthesis suppression. Therefore, GTE exerted mechanisms involving both promotion and suppression activities, whereas purified catechins induced extensive apoptosis. GTE could be a more promising antineovascularization remedy for ocular treatment.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences , The Chinese University of Hong Kong, Hong Kong Eye Hospital , Kowloon , Hong Kong
- School of Biomedical Sciences , The Chinese University of Hong Kong , Shatin , New Territories , Hong Kong
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences , The Chinese University of Hong Kong, Hong Kong Eye Hospital , Kowloon , Hong Kong
| | - Sun On Chan
- School of Biomedical Sciences , The Chinese University of Hong Kong , Shatin , New Territories , Hong Kong
| | - Tsz Kin Ng
- Department of Ophthalmology and Visual Sciences , The Chinese University of Hong Kong, Hong Kong Eye Hospital , Kowloon , Hong Kong
| | - Vishal Jhanji
- Department of Ophthalmology and Visual Sciences , The Chinese University of Hong Kong, Hong Kong Eye Hospital , Kowloon , Hong Kong
| | - Chi Chiu Wang
- School of Biomedical Sciences , The Chinese University of Hong Kong , Shatin , New Territories , Hong Kong
- Department of Obstetrics and Gynaecology , The Chinese University of Hong Kong , Shatin , New Territories , Hong Kong
- Li Ka Shing Institute of Health Science , The Chinese University of Hong Kong , Shatin , New Territories , Hong Kong
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences , The Chinese University of Hong Kong, Hong Kong Eye Hospital , Kowloon , Hong Kong
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Li J, Ren J, Yip YWY, Zhang X, Chu KO, Ng TK, Chan SO, Pang CP, Chu WK. Quantitative Characterization of Autoimmune Uveoretinitis in an Experimental Mouse Model. Invest Ophthalmol Vis Sci 2017; 58:4193-4200. [PMID: 28837731 DOI: 10.1167/iovs.17-22436] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To accurately evaluate the autoimmune inflammation, we aim to develop three quantitative measurements to monitor the inflammatory changes in the retina: retinal-choroidal thickness, major retinal vessel diameter, and electroretinography amplitudes. Methods During a 21-day experimental period, eyes were examined by confocal scanning laser ophthalmoscopy, optical coherence tomography, fundus fluorescein angiography, and electroretinography in living mice, which were then subsequently killed for histologic assessments. Results On day 21 postimmunization, inflammation was observed both in vivo and in vitro. Fold change of retinal-choroidal thickness and major retinal vessel diameter in experimental autoimmune uveoretinitis mice were significantly greater than controls (P < 0.001). Both scotopic and photopic electroretinography amplitudes were significantly attenuated when compared with control mice (P < 0.01). Our results showed that these three quantifiable indicators provided an objective and accurate evaluation of autoimmune inflammation, which are in good correlations with the reported clinical and histopathologic scoring systems (P < 0.05). Conclusions These three indicators will be useful to detect the small but significant differences in the severity of experimental autoimmune uveoretinitis for future longitudinally therapeutic studies.
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Affiliation(s)
- Jian Li
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Jialin Ren
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Yolanda Wong Ying Yip
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Xiaoyu Zhang
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Kai On Chu
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Tsz Kin Ng
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Sun On Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Chi Pui Pang
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
| | - Wai Kit Chu
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China
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Chan TCY, Ye C, Chan KP, Chu KO, Jhanji V. Evaluation of point-of-care test for elevated tear matrix metalloproteinase 9 in post-LASIK dry eyes. Br J Ophthalmol 2015; 100:1188-91. [DOI: 10.1136/bjophthalmol-2015-307607] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/28/2015] [Indexed: 11/04/2022]
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Chu KO, Chan KP, Yang YP, Qin YJ, Li WY, Chan SO, Wang CC, Pang CP. Effects of EGCG content in green tea extract on pharmacokinetics, oxidative status and expression of inflammatory and apoptotic genes in the rat ocular tissues. J Nutr Biochem 2015; 26:1357-67. [PMID: 26362107 DOI: 10.1016/j.jnutbio.2015.07.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 05/21/2015] [Accepted: 07/06/2015] [Indexed: 12/31/2022]
Abstract
Green tea extract (GTE) exerts antioxidative activities in ocular tissues of rats, but high levels of (-)-epigallocatechin gallate (EGCG) can induce oxidative stress. In this study, pharmacokinetics, diurnal variation of oxidative status, antioxidation and transcription factors changes in ocular tissues of rats were investigated. Rats were fed intragastrically with GTE and catechin mixtures containing different amounts of EGCG. Plasma and various ocular tissues were taken for pharmacokinetic analysis, oxidation marker testings and gene expression assays. Effects of EGCG on ocular oxidation status were assessed by 8-isoprostane level and reduced/oxidized glutathione ratio. Oxidation, inflammation and apoptosis regulations in retina were evaluated by real-time polymerase chain reaction. Epicatechin, epigallocatechin and EGCG were dominant in various ocular tissues except vitreous humor, where gallocatechin was predominant. Diurnal variation of oxidative status was found in some compartments. GTE caused oxidative stress increase in the plasma, aqueous humor, vitreous humor, cornea and retina but decrease in the lens and choroid-sclera. Catechins mixture containing half dose of EGCG lowered 8-isoprostane in the retina and lens. GTE treatment induced superoxide dismutase 1 and glutathione peroxidase-3 expressions but suppressed catalase in the retina. Our results reveal pro-oxidation of GTE with high EGCG content to the ocular tissues. Optimal EGCG level is needed for protection.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong; Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Ya Ping Yang
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Yong Jie Qin
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Wai Ying Li
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong
| | - Sun On Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong.
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Chu KO, Man GCW, Chan KP, Chu CY, Chan TH, Pang CP, Wang CC. Determination of exogenous epigallocatechin gallate peracetate in mouse plasma using liquid chromatography with quadrupole time-of-flight mass spectrometry. J Sep Sci 2014; 37:3473-80. [DOI: 10.1002/jssc.201400701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/18/2014] [Accepted: 09/12/2014] [Indexed: 12/26/2022]
Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences; The Chinese University of Hong Kong; Hong Kong Eye Hospital; Kowloon Hong Kong
- Department of Obstetrics and Gynaecology; The Chinese University of Hong Kong; Prince of Wales Hospital; Shatin New Territories Hong Kong
| | - Gene Chi Wai Man
- Department of Obstetrics and Gynaecology; The Chinese University of Hong Kong; Prince of Wales Hospital; Shatin New Territories Hong Kong
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences; The Chinese University of Hong Kong; Hong Kong Eye Hospital; Kowloon Hong Kong
| | - Ching Yan Chu
- Department of Obstetrics and Gynaecology; The Chinese University of Hong Kong; Prince of Wales Hospital; Shatin New Territories Hong Kong
| | - Tak Hang Chan
- Department of Applied Biology and Chemical Technology; The Hong Kong Polytechnic University; Hung Hom Kowloon Hong Kong
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences; The Chinese University of Hong Kong; Hong Kong Eye Hospital; Kowloon Hong Kong
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology; The Chinese University of Hong Kong; Prince of Wales Hospital; Shatin New Territories Hong Kong
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Qin YJ, Chu KO, Yip YWY, Li WY, Yang YP, Chan KP, Ren JL, Chan SO, Pang CP. Green tea extract treatment alleviates ocular inflammation in a rat model of endotoxin-induced uveitis. PLoS One 2014; 9:e103995. [PMID: 25093862 PMCID: PMC4122397 DOI: 10.1371/journal.pone.0103995] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 07/06/2014] [Indexed: 12/14/2022] Open
Abstract
Green tea extract (GTE) ingested by rats exerted anti-oxidative activities in various ocular tissues as shown in our previous studies. The present work investigated anti-inflammatory effects of GTE on endotoxin-induced uveitis (EIU). EIU was generated in adult rats by a footpad injection of 1 mg/kg lipopolysaccharide (LPS). Oral administration of GTE (550 mg/kg) was given one, two or four times after LPS injection. Twenty-four hours later, LPS produced severe hyperemia and edema in the iris. Immunocytochemical examinations showed an accumulation of infiltrating cells in the aqueous humor that were immunopositive for cluster of differentiation 43 (CD43) and CD68, markers for leucocytes and macrophages, respectively. Analyses of the aqueous humor showed an increase in pro-inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1). GTE treatments improved the clinical manifestations and reduced infiltrating cells and protein exudation in the aqueous humor, which were not observed under half dose of GTE (275 mg/kg). The number of CD68 positive macrophages residing in the iris and ciliary was also reduced. GTE suppressed production of TNF-α, IL-6 and MCP-1 in the aqueous humor, which was associated with a down-regulation of LPS receptor complex subunits, Toll-like receptor 4 (TLR-4) and CD14, and suppression of nuclear factor-kappa Bp65 (NF-κBp65) in the iris and ciliary body. Our findings show that GTE is a potent anti-inflammatory agent against the inflammation of EIU, and suggest a potential use in treatment of acute uveitis.
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Affiliation(s)
- Yong Jie Qin
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Yolanda Wong Ying Yip
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Wai Ying Li
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Ya Ping Yang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Jia Lin Ren
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Sun On Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail: (CPP); (SOC)
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
- * E-mail: (CPP); (SOC)
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Chu KO, Chan SO, Pang CP, Wang CC. Pro-oxidative and antioxidative controls and signaling modification of polyphenolic phytochemicals: contribution to health promotion and disease prevention? J Agric Food Chem 2014; 62:4026-4038. [PMID: 24779775 DOI: 10.1021/jf500080z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Polyphenolic phytochemicals (PPs) have been extensively studied as potential nutriceuticals for maintenance of health and treatment of cancer, inflammation, and neurodegeneration. However, the reported beneficial outcomes are inconsistent. The biological activities of PPs have been attributed to their pro-oxidative and antioxidative actions and effects on signaling mechanisms and epigenomic modifications. These diversified properties were described or postulated on the basis of a variety of experimental studies using cell culture and animal models, even though most have not been replicated and results are not validated. This review attempts to give an overview of biological properties of PPs, based on the coherent results from relevant studies, and evaluate critically the experimental conditions and possible artifacts. Complicated molecular mechanisms and multitargeting genomic interactions of PPs are discussed, with a view that reasonable mechanistic propositions are usually obtained from well-designed in vivo studies.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong in Hong Kong Eye Hospital , Kowloon, Hong Kong
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Wang CC, Fung KP, Fok TF, Lau TK, Pang CP, Chu KO, Shum ASW, Lam CWK, Chan MHM, Ho CS, Lau CM, Ting TL, Mak TCW. Melamine toxicity in rat foetuses and infants. Hong Kong Med J 2013; 19 Suppl 8:20-22. [PMID: 24473523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Affiliation(s)
- C C Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong
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Chu KO, Liu DTL, Chan KP, Yang YP, Yam GHF, Rogers MS, Pang CP. Quantification and Structure Elucidation of in Vivo Bevacizumab Modification in Rabbit Vitreous Humor after Intravitreal Injection. Mol Pharm 2012; 9:3422-33. [DOI: 10.1021/mp3005403] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Wang CC, Xu H, Man GCW, Zhang T, Chu KO, Chu CY, Cheng JTY, Li G, He YX, Qin L, Lau TS, Kwong J, Chan TH. Prodrug of green tea epigallocatechin-3-gallate (Pro-EGCG) as a potent anti-angiogenesis agent for endometriosis in mice. Angiogenesis 2012; 16:59-69. [PMID: 22948799 DOI: 10.1007/s10456-012-9299-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/22/2012] [Indexed: 01/31/2023]
Abstract
Green tea epigallocatechin-3-gallate (EGCG) can inhibit angiogenesis and development of an experimental endometriosis model in mice, but it suffers from poor bioavailability. A prodrug of EGCG (pro-EGCG, EGCG octaacetate) is utilized to enhance the stability and bioavailability of EGCG in vivo. In this study, the potential of pro-EGCG as a potent anti-angiogenesis agent for endometriosis in mice was investigated. Homologous endometrium was subcutaneously transplanted into mice to receive either saline, vitamin E, EGCG or pro-EGCG treatment for 4 weeks. The growth of the endometrial implants were monitored by IVIS(®) non-invasive in vivo imaging during the interventions. Angiogenesis of the endometriotic lesions was determined by Cellvizio(®) in vivo imaging and SCANCO(®) Microfil microtomography. The bioavailability, anti-oxidation and anti-angiogenesis capacities of the treatments were measured in plasma and lesions. The implants with adjacent outer subcutaneous and inner abdominal muscle layers were collected for histological, microvessel and apoptosis examinations. The result showed that EGCG and pro-EGCG significantly decreased the growth of endometrial implants from the 2nd week to the 4th week of intervention. EGCG and pro-EGCG significantly reduced the lesion size and weight, inhibited functional and structural microvessels in the lesions, and enhanced lesion apoptosis at the end of interventions. The inhibition by pro-EGCG in all the angiogenesis parameters was significantly greater than that by EGCG, and pro-EGCG also had better bioavailability and greater anti-oxidation and anti-angiogenesis capacities than EGCG. Ovarian follicles and uterine endometrial glands were not affected by either EGCG or pro-EGCG. Vitamin E had no effect on endometriosis. In conclusion, pro-EGCG significantly inhibited the development, growth and angiogenesis of experimental endometriosis in mice with high efficacy, bioavailability, anti-oxidation and anti-angiogenesis capacities. Pro-EGCG could be a potent anti-angiogenesis agent for endometriosis.
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Affiliation(s)
- Chi Chiu Wang
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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Pong JCF, Chu CY, Chu KO, Poon TCW, Ngai SM, Pang CP, Wang CC. Identification of hemopexin in tear film. Anal Biochem 2010; 404:82-5. [PMID: 20450875 DOI: 10.1016/j.ab.2010.04.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 04/29/2010] [Indexed: 10/19/2022]
Abstract
Human tear fluid is a complex mixture of aqueous lipids, proteins, enzymes, and other biochemical and cellular elements. By conventional comparative proteomic approaches, we investigated the proteome in human tear fluid and compared the tear protein profile of normal control subjects with that of patients suffering from the ocular inflammatory disease vernal keratoconjunctivitis (VKC). Collected tear samples were directed to two-dimensional polyacrylamide gel electrophoresis protein separation and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry peptide identification. Six differentially expressed proteins-interleukin 4, phospholipase A2, albumin, lactoferrin, hemopexin, and lipocalin-were displayed. Hemopexin had not been reported previously in tear film. Enzyme-linked immunosorbent assay confirmed that hemopexin concentrations were significantly higher in VKC tear samples and increased with disease stages. The results implied clinical interest of hemopexin in the tear proteome and eye diseases.
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Affiliation(s)
- Jeffrey C F Pong
- Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong
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Chu KO, Chan KP, Wang CC, Chu CY, Li WY, Choy KW, Rogers MS, Pang CP. Green tea catechins and their oxidative protection in the rat eye. J Agric Food Chem 2010; 58:1523-1534. [PMID: 20085274 DOI: 10.1021/jf9032602] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Catechins, active constituents of green tea, are well-known antioxidative natural products. It was proposed that green tea extract (GTE) consumption could benefit the eye, and the pharmacokinetics of catechins and oxidation status in rat eye were investigated after oral administration. Sprague-Dawley rats were fed GTE and sacrificed at different time intervals. Their eyes were dissected into cornea, lens, retina, choroid-sclera, vitreous humor, and aqueous humor for analysis of catechins and 8-epi-isoprostane by HPLC-ECD and GC-NCI-MS, respectively. Catechins were differentially distributed in eye tissues. Gallocatechin was present at the highest concentration in the retina, 22729.4 +/- 4229.4 pmol/g, and epigallocatechin in aqueous humor at 602.9 +/- 116.7 nM. The corresponding area-under-curves were 207,000 pmol x h/g and 2035.0 +/- 531.7 nM x h, respectively. The time of maximum concentration of the catechins varied from 0.5 to 12.2 h. Significant reductions in 8-epi-isoprostane levels were found in the compartments except the choroid-sclera or plasma, indicating antioxidative activities of catechins in these tissues.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong
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Chu KO, Wang CC, Pang CP, Rogers MS. Method to determine stability and recovery of carboprost and misoprostol in infusion preparations. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 857:83-91. [PMID: 17692579 DOI: 10.1016/j.jchromb.2007.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Revised: 06/26/2007] [Accepted: 07/01/2007] [Indexed: 11/15/2022]
Abstract
The two synthetic prostaglandin analogues, carboprost and misoprostol, are used extensively in obstetric and gynaecological practice. Our recent research of these compounds' use for intra-umbilical injection to treat adherent placenta necessitated their storage in solution for 3-4 days. This raised concerns over the stability and applied dosage in the in-house infusion preparations. It requires various pharmacological preparations before administration in clinical practice. We used LCMS to develop a simultaneous, valid, fast and simple method to assess the stability and recovery of their in-house preparations in different conditions. The linearity between 0-40 microg/ml was above 0.995. The reproducibility (CV) was within 5.2%. The limit of quantitation of the method for both compounds is about 2 microg/ml. The accuracy of both compounds from 0.4-40 microg/ml is 96.4-104.3% while the precision is 0.4-7.4%. The recoveries of carboprost in the infusion were from 100.3+/-4.0 to 102.4+/-1.6% and that of misoprostol in Cytotec tablet was from 44.9+/-3.5 to 50.0+/-5.0% in water and saline at 4 degrees C and room temperature. No interference was found from the matrix and between the tested compounds. The compounds were basically stable for 6 days in water and in saline, whether they were stored at 4 degrees C or at room temperature. However, only half of the dosage of misoprostol was recovered in the solution. Therefore, misoprostol dosage should be adjusted before clinical application.
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Affiliation(s)
- Kai On Chu
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, NT, Hong Kong
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Wang CC, Chu KO, Chong WS, Li WY, Pang CP, Shum ASW, Lau TK, Rogers MS. Tea epigallocatechin-3-gallate increases 8-isoprostane level and induces caudal regression in developing rat embryos. Free Radic Biol Med 2007; 43:519-27. [PMID: 17640562 DOI: 10.1016/j.freeradbiomed.2007.04.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2007] [Revised: 04/26/2007] [Accepted: 04/26/2007] [Indexed: 10/23/2022]
Abstract
Tea is the most common beverage after water. Concerns have been raised about the safety of tea during pregnancy, especially for embryo development. We aimed at studying the effects of active tea components on developing embryos by in vitro rat embryo culture. Rat embryos during early organogenesis were cultivated in serum supplemented with one of the tea catechins. Developmental hallmarks and malformations (Mal) in the developing embryos were compared and evaluated by a standard morphological scoring system. The embryotoxicity of each tea catechin was classified according to the European Center for the Validation of Alternative Methods. Cell viability was assessed by supervital dye staining, apoptosis by TUNEL assay, and peroxidation by the 8-isoprostane EIA method. We found that (+)-catechin had the least effect on developing embryos (Mal(50)=715.1 mg/L; IC50(Mal)=435 mg/L), whereas (-)-epigallocatechin gallate had the most adverse effect (Mal(50)=54.2 mg/L; IC50(Mal)=45.8 mg/L). The major malformation in affected embryos included caudal retardation with abnormal axial flexion and delayed hind-limb formation. All catechins were classified as nonembryotoxic except (-)-epigallocatechin gallate, which was classified as weakly embryotoxic. With (-)-epigallocatechin gallate, increased numbers of nonviable and apoptotic cells in the malformed embryos were associated with increased embryo 8-isoprostane.
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Affiliation(s)
- Chi Chiu Wang
- Li Ka Shing Institute of Health Sciences, Faculty of Medicine, Shatin, New Territories, Hong Kong.
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Lai WW, Chu KO, Chan KP, Choy KW, Wang CC, Tsang CW, Pang CP. Differential aqueous and vitreous concentrations of moxifloxacin and ofloxacin after topical administration one hour before vitrectomy. Am J Ophthalmol 2007; 144:315-8. [PMID: 17659971 DOI: 10.1016/j.ajo.2007.03.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 03/14/2007] [Accepted: 03/21/2007] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate the penetration of ofloxacin and moxifloxacin into the aqueous and vitreous after topical administration one hour before vitrectomy surgery. DESIGN Prospective, randomized, double-blind case series study. METHODS Twenty-seven patients undergoing vitrectomy were randomized to receive either topical ofloxacin 0.3% or moxifloxacin 0.5% every 10 minutes for one hour before surgery. Aqueous and vitreous samples were obtained and analyzed using high-performance liquidation chromatography. RESULTS The moxifloxacin aqueous (1.576 +/- 0.745 microg/ml) and vitreous (0.225 +/- 0.013 microg/ml) levels were significantly higher than the ofloxacin aqueous (0.816 +/- 0.504 microg/ml) (P = .0009) and vitreous (0.225 +/- 0.013 microg/ml) [P = .0054] levels, respectively. The mean moxifloxacin aqueous and vitreous levels exceeded the minimum inhibitory concentration for 90% of isolates (MIC(90)) for a wide variety of bacteria implicated in endophthalmitis. In contrast, the aqueous level of ofloxacin exceeded the MIC(90) of only a few organisms. CONCLUSIONS Moxifloxacin applied every 10 minutes during the hour before vitrectomy penetrated the eye significantly better than ofloxacin.
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Affiliation(s)
- Wico W Lai
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.
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Chu KO, Ho TC, Chiang WY, Wang CC, Lam DSC, Pang CP. Measuring triamcinolone acetonide in aqueous humor by gas chromatography-electron-capture negative-ion mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 847:199-204. [PMID: 17097356 DOI: 10.1016/j.jchromb.2006.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2006] [Revised: 09/06/2006] [Accepted: 10/06/2006] [Indexed: 11/19/2022]
Abstract
Intravitreal triamcinolone acetonide (IVTA) injection has been used in the treatment of various posterior segment diseases. One of the side effects of IVTA is raised intraocular pressure, which may be secondary to triamcinolone acetonide (TAA)'s effects on the trabecular meshwork that affects aqueous outflow. In order to study the biological effects of TAA on the trabecular meshwork, we firstly need to reliably and accurately detect the concentration of TAA in tissue cells or fluids. In this study we have described a technique of using gas chromatography-electron-capture-negative-ion mass spectrometry (GC-NCI-MS) to develop a simple, sensitive, selective and validated method to detect TAA in aqueous humor (AH) of rabbits following IVTA and subconjunctival TAA injections. We derivatized TAA from extracted aqueous sample by acetic anhydride and BSTFA, respectively, and analyzed by GC-NCI-MS. The detection limit was 0.3ng/ml, linearity over 0.995 from 0 to 300ng/ml. The reproducibility ranged from 10.4 to 3.9 for concentrations from 3 to 300ng/ml, and recovery was over 95% for the concentrations 10, 60, and 200ng/ml. No interference was found from 159 aqueous samples. There was no TAA residue carried to the next injection from previously high concentration injection, 10,000ng/ml. We have provided an alternative, rapid, and robust method other than LC-MS-MS for TAA detection in AH.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
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Chu KO, Wang CC, Chu CY, Choy KW, Pang CP, Rogers MS. Uptake and distribution of catechins in fetal organs following in utero exposure in rats. Hum Reprod 2006; 22:280-7. [PMID: 16959805 DOI: 10.1093/humrep/del353] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Although catechins are known to be powerful antioxidants, no reports have shown their transport to fetal organs. We investigated the distribution of catechins in fetal rat organs after maternal exposure to green tea extract (GTE). METHODS GTE (550 mg/kg) or water was fed orally to pregnant dams at 15.5 days of gestation, the dams were sacrificed and fetal organs were dissected 0, 0.5, 1, 2, 3, 5, and 8 h later. Catechins and catechin gallates were determined by high-performance liquid chromatography (HPLC) after solid-phase extraction. RESULTS In the GTE-treated group, catechins were detected in most of the fetal organs studied, including the brain, eyes, heart, lungs, kidneys and liver but not in the control group. The first peak times (T(max)) were about 0.5-1 h. The maximum concentrations (C(max)) of catechins in the fetal eye were about 2-10 times higher than in the other organs, ranging from 249 pmol/g for epicatechin (EC) to 831 pmol/g for epigallocatechin gallate (EGCG). Catechin gallates were generally more readily taken up by fetal organs than catechins. EGCG had the highest level of uptake according to area under the curve (AUC) plots and the highest C(max) in all organs. CONCLUSIONS Various fetal organs had low but significant levels of catechins after GTE intake by the dams, and organ levels were found to be related to catechin structure. EGCG could be a potential candidate for antioxidant supplementation of the fetus in utero.
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Affiliation(s)
- K O Chu
- Department of Obstetrics and Gynaecology, The Chinese Univerity of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong
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Abstract
OBJECTIVES To explore the relationship between the levels of maternal oxidative stress and glycaemia during pregnancy and to compare the predictive values of 8-epimer of prostaglandin F(2alpha) (8-isoPGF(2alpha)) and mean arterial pressure (MAP) in midpregnancy for the development of hypertensive complications in later pregnancy. DESIGN Prospective observational study as an ancillary study to the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) study. SETTING Obstetric clinics and wards of a university teaching hospital in Hong Kong. POPULATION Selected women with singleton pregnancies attending the antenatal clinic. METHODS Pregnant women who met HAPO inclusion criteria were recruited for the study. Glucose tolerance was assessed by a 75-g 2-hour oral glucose tolerance test (OGTT) at 24-32 weeks of gestation. Fasting plasma samples for 8-isoPGF(2alpha) estimation and urine samples for 8-isoPGF(2alpha) and 2,3-dinor 8-isoPGF(2alpha) assays were collected and blood pressures measured during the OGTT visit. Random plasma and urine samples were also obtained at 34-37 weeks. Glucose results were unblinded to the attending obstetrician if limits preset under the HAPO protocol were met. MAIN OUTCOME MEASURES Maternal plasma 8-isoPGF(2alpha) and urinary 8-isoPGF(2alpha) and 2,3-dinor 8-isoPGF(2alpha) both at the time of OGTT (24-32 weeks) and at 34-37 weeks of gestation. Incidence of pre-eclampsia and gestational hypertension. RESULTS Of the 408 women who attended for OGTT at 24-32 weeks, two met the glucose criteria for unblinding and 25 had missing 8-isoPGF(2alpha) values and thus were excluded from analysis. Of the 381 women, 338 (88.7%) attended for random plasma samples at 34-37 weeks. Significant correlations were observed between maternal fasting plasma isoprostane and both fasting (r= 0.20; P < 0.001) and 2-hour (r= 0.39; P < 0.001) plasma glucose levels at the time of OGTT. Gestational hypertension/pre-eclampsia occurred in 17 (4.2%) women, and at the time of OGTT, they had significantly higher fasting plasma 8-isoPGF(2alpha) (P < 0.001), urine 8-isoPGF(2alpha) (P < 0.005) and urine 2,3-dinor 8-isoPGF(2alpha) to creatinine ratios (P < 0.001), as well as higher MAP (P < 0.001) than women who remained normotensive. At 34-37 weeks, only random plasma 8-isoPGF(2alpha) was significantly higher (P < 0.001) among the women with gestational hypertension/pre-eclampsia. CONCLUSIONS Plasma markers of oxidative stress were positively correlated with plasma glucose at the time of OGTT (24-32 weeks). Women who subsequently developed gestational hypertension/pre-eclampsia had significantly higher plasma and urine markers of oxidative stress at the time of OGTT but only higher plasma markers at 34-37 weeks. Plasma 8-isoPGF(2alpha) appears to be a very good predictor of subsequent gestational hypertension/pre-eclampsia when measured at the time of OGTT, but its ability to discriminate deteriorates as pregnancy advances.
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Affiliation(s)
- M S Rogers
- Department of Obstetrics and Gynaecology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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Chan KP, Chu KO, Lai WWK, Choy KW, Wang CC, Lam DSC, Pang CP. Determination of ofloxacin and moxifloxacin and their penetration in human aqueous and vitreous humor by using high-performance liquid chromatography fluorescence detection. Anal Biochem 2006; 353:30-6. [PMID: 16620758 DOI: 10.1016/j.ab.2006.03.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2005] [Revised: 03/06/2006] [Accepted: 03/09/2006] [Indexed: 11/16/2022]
Abstract
Information on comparing the penetration of ofloxacin and moxifloxacin in the human eye is unavailable, although these two antibiotics are commonly used in ophthalmic surgery. There is a need for a rapid, reliable, and sensitive methodology for their determination in ocular fluids. We developed a robust HPLC procedure with fluorescence detection for simultaneous analysis of ofloxacin and moxifloxacin in human and rabbit aqueous and vitreous samples. The linearity of the method ranged from 10 ng/ml to 100 microg/ml with r(2) > 0.996. Most inter- and intrabatch imprecision was about 5% (range 1.6-7.6%), recoveries between 95 and 104%, and accuracies between 93 and 104% at 0.1 and 1 microg/ml. The detection limits of both compounds were 10 ng/ml (0.028 nmol/ml for ofloxacin and 0.023 nmol/ml for moxifloxacin). No sample treatment was necessary for aqueous humor and only acetonitrile precipitation was required for vitreous humor. The chromatographic time was short, 22 min. We applied this method to study penetrations of ofloxacin and moxifloxacin in aqueous and vitreous humors of human and rabbits. There was no significant difference of penetration between the two antibiotics into aqueous and vitreous but ofloxacin was found at significantly higher concentrations in aqueous than in vitreous. We also detected contralateral transfer of the antibiotics in rabbit eyes.
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Affiliation(s)
- Kwok Ping Chan
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, China
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Chu KO, Wang CC, Chu CY, Chan KP, Rogers MS, Choy KW, Pang CP. Pharmacokinetic studies of green tea catechins in maternal plasma and fetuses in rats. J Pharm Sci 2006; 95:1372-81. [PMID: 16625654 DOI: 10.1002/jps.20594] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We carried out a pharmacokinetic study to determine the levels and profiles of catechins in pregnant rats and their fetuses after ingestion of green tea extract (GTE). We measured total catechin levels after enzyme digestions. Dams, at 15.5 days of gestation, were fed with GTE and catechins were measured in the maternal plasma, placenta, and fetus 0, 0.5, 1, 2, 3, 5, 8, 10, 12, 16, and 20 h after maternal GTE intake. The pharmacokinetic changes were analyzed by non compartmental models. We found that maternal plasma concentrations of catechins were about 10 times higher than in placenta and 50-100 times higher than in the fetus. AUC and Cmax levels of (-)-epicatechin (EC) were the highest in plasma while the levels of (-)-epigallocatechin gallate (EGCG) were the highest in the placenta and the fetus. The exposure level of catechin derivatives was higher than the gallate derivatives in maternal plasma after normalization but reversed in the placenta and fetus. The absorption of epi-isomers in plasma was found to be more favorable than their non epi-isomer counterparts. EGCG had the highest level of exposure (AUC) and the highest Cmax in the fetus, implying it may have potential for in utero antioxidant protection.
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Affiliation(s)
- Kai On Chu
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, 3/F, Hong Kong Eye Hospital, 147K, Argyle Street, Kowloon, Hong Kong
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Rogers MS, Wang CC, Lau TK, Xiao X, Zhou XG, Fok TF, Chu KO, Pang CP. Relationship between Isoprostane Concentrations, Metabolic Acidosis, and Morbid Neonatal Outcome. Clin Chem 2005; 51:1271-4. [PMID: 15976110 DOI: 10.1373/clinchem.2004.047241] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Michael Scott Rogers
- Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.
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Chu KO, Wang CC, Chu CY, Rogers MS, Choy KW, Pang CP. Determination of catechins and catechin gallates in tissues by liquid chromatography with coulometric array detection and selective solid phase extraction. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 810:187-95. [PMID: 15380714 DOI: 10.1016/j.jchromb.2004.07.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Accepted: 07/19/2004] [Indexed: 10/01/2022]
Abstract
Catechins levels in organ tissues, particularly liver, determined by published methods are unexpectedly low, probably due to the release of oxidative enzymes, metal ions and reactive metabolites from tissue cells during homogenization and to the pro-oxidant effects of ascorbic acid during sample processing in the presence of metal ions. We describe a new method for simultaneous analysis of eight catechins in tissue: (+)-catechin (C), (-)-epicatechin (EC), (-)-gallocatechin (GC), (-)-epigallocatechin (EGC), (-)-catechin gallate (CG), (-)-epicatechin gallate (ECG), (-)-gallocatechin gallate (GCG) and (-)-epigallocatechin gallate (EGCG) (Fig. 1). The new extraction procedure utilized a methanol/ethylacetate/dithionite (2:1:3) mixture during homogenization for simultaneous enzyme precipitation and antioxidant protection. Selective solid phase extraction was used to remove most interfering bio-matrices. Reversed phase HPLC with CoulArray detection was used to determine the eight catechins simultaneously within 25 min. Good linearity (>0.9922) was obtained in the range 20-4000 ng/g. The coefficients of variance (CV) were less than 5%. Absolute recovery ranged from 62 to 96%, accuracy 92.5 +/- 4.5 to 104.9 +/- 6%. The detection limit was 5 ng/g. This method is capable for determining catechins in rat tissues of liver, brain, spleen, and kidney. The method is robust, reproducible, with high recovery, and has been validated for both in vitro and in vivo sample analysis.
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Affiliation(s)
- Kai On Chu
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, 3/F Hong Kong Eye Hospital, 147K Argyle Street, Kowloon, Hong Kong
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Wang CC, Chu CY, Chu KO, Choy KW, Khaw KS, Rogers MS, Pang CP. Trolox-Equivalent Antioxidant Capacity Assay Versus Oxygen Radical Absorbance Capacity Assay in Plasma. Clin Chem 2004; 50:952-4. [PMID: 15105359 DOI: 10.1373/clinchem.2004.031526] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Chi Chiu Wang
- Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
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Abstract
We attempted to improve the extraction procedures to determine the F(2)-isoprostanes in plasma of umbilical cord arterial and venous blood by gas chromatography mass spectrometry. Plasma samples were deproteinized and hydrolyzed; free and esterified F(2)-isoprostanes were extracted by solid-phase extraction columns with citric acid/methanol/cyclohexane and ammonia solution/methanol and then derivatized by PFBBr and BSTFA. Concentrations of total plasma F(2)-isoprostanes eluted at the retention time of an internal standard of 8-iso-prostaglandin F(2alpha)-D(4) were quantified. The absolute recovery was 83+/-1.9% (95% confidence). Intraassay precision and interassay precision were lower than 1.0%. Analytical accuracy was 99.0+/-0.4% (95% confidence). Linearity, r(2), over the concentration range of 10 to 5000 pg/ml of spiked 8-iso-prostaglandin F(2alpha) in plasma was 0.9985. The method detection limit was 21 pg/ml (99% confidence) and the limit of quantitation was approximately 4 pg/ml. Analysis of 200 neonatal cord blood samples revealed few overlapping peaks causing interference in the elution of the F(2)-isoprostanes. With the use of an autosampler and one technician, 48 samples can be completed within 24h with 6h of actual hands-on work. This method could be potentially employed for routine analysis of plasma F(2)-isoprostanes in clinical laboratories.
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Affiliation(s)
- Kai On Chu
- Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
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