Ching Yan Chu

Anti-angiogenic effects of green tea catechin on an experimental endometriosis mouse model

BACKGROUND The development of new blood vessels plays an essential role in growth and survival of endometriosis. Epigallocatechin gallate (EGCG) from green tea has powerful anti-angiogenic properties and our aim was to evaluate these properties in experimental endometriosis. METHODS AND RESULTS Eutopic endometrium from endometriosis patients was transplanted s.c. to severely compromised immunodeficient mice, randomly treated i.p. with EGCG (anti-angiogenic and -oxidant), Vitamin E (a non-angiogenic antioxidant) or saline for 2 weeks. The endometrial implant, including adjacent host outer skin and subcutaneous layers plus inner abdominal muscle and peritoneum, was collected. New microvessels were determined by species-specific immunohistochemistry. Angiogenic factors in lesions and abdominal muscle were detected by quantitative real-time PCR. Apoptosis was studied by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling and quantitative real-time PCR. In saline control, endometrial implants developed new blood vessels with proliferating glandular epithelium and were tightly adhered to host subcutaneous and abdominal muscle layers. After EGCG, endometriotic lesions were smaller than control (P < 0.05), and glandular epithelium was smaller and eccentrically distributed. Angiogenesis in lesions from the implant and adjacent tissues was under-developed, and microvessel size and density were lower (both P < 0.01) than control. mRNA for angiogenic vascular endothelial growth factor A, but not hypoxia inducible factor 1, alpha subunit, was significantly down-regulated in lesions after EGCG (P < 0.05). In addition, apoptosis in the lesions was more obvious, and nuclear factor kappa B and mitogen activated protein kinase 1 mRNA levels were up-regulated (P < 0.05) after EGCG treatment. No differences were observed with Vitamin E treatment. CONCLUSIONS EGCG significantly inhibits the development of experimental endometriosis through anti-angiogenic effects.

Green tea epigallocatechin-3-gallate inhibits angiogenesis and suppresses vascular endothelial growth factor C/vascular endothelial growth factor receptor 2 expression and signaling in experimental endometriosis in vivo

OBJECTIVE To investigate the antiangiogenesis mechanism of epigallocatechin-3-gallate (EGCG) in an endometriosis model in vivo. DESIGN Animal studies. SETTING University laboratory. ANIMAL(S) Human endometrium from women with endometriosis (n = 10) was transplanted into immunocompromised mice. INTERVENTION(S) Mice (n = 30) were randomly treated with EGCG, vitamin E (antioxidant control), or vehicle (negative control) for microvessel imaging. MAIN OUTCOME MEASURE(S) Endometriotic implants were collected for angiogenesis microarray and pathway analysis. Differentially expressed angiogenesis molecules were confirmed by quantitative polymerase chain reaction, Western blot, and immunohistochemistry. Effects of EGCG on angiogenesis signal transduction were further characterized in a human endothelial cell line. Microvessel parameters and the angiogenesis signaling pathway in endometriotic implants and endothelial cells were studied. RESULT(S) EGCG, but not vitamin E, inhibited microvessels in endometriotic implants. EGCG selectively suppressed vascular endothelial growth factor C (VEGFC) and tyrosine kinase receptor VEGF receptor 2 (VEGFR2) expression. EGCG down-regulated VEGFC/VEGFR2 signaling through c-JUN, interferon-γ, matrix metalloproteinase 9, and chemokine (C-X-C motif) ligand 3 pathways for endothelial proliferation, inflammatory response, and mobility. EGCG also suppressed VEGFC expression and reduced VEGFR2 and ERK activation in endothelial cells. VEGFC supplementation attenuated the inhibitory effects by EGCG. CONCLUSION(S) EGCG inhibited angiogenesis and suppressed VEGFC/VEGFR2 expression and signaling pathway in experimental endometriosis in vivo and endothelial cells in vitro.

Green Tea Catechins and Their Oxidative Protection in the Rat Eye

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.

Distribution of melamine in rat foetuses and neonates.

Pharmacokinetics of melamine has not been studied in pregnancies despite of the many reports on the effect on renal damage in adult and neonates. In this study, Sprague-Dawley rats have been used as a model to study the single-dose effect of melamine administration in late pregnancy and in neonates within 24h. Melamine concentrations in maternal serum, breast milk, whole foetus, amniotic fluid, neonatal serum and neonatal kidney was measured by liquid chromatography coupled with mass spectrometry. Melamine was detected in all the samples, including foetal rats and amniotic fluid in utero. Melamine was able to pass through placenta and reach the foetus, and to accumulate in lactating mammary gland and neonatal kidney. Moreover, melamine was eliminated through the placenta of the foetus and the kidneys of the neonates, and later excreted into the amniotic fluid. The study characterised for the first time the distribution of melamine in foetuses and neonates, providing reference for toxicological study of melamine during pregnancy.

Oxidative stress in midpregnancy as a predictor of gestational hypertension and pre-eclampsia.

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 F2alpha (8‐isoPGF2α) and mean arterial pressure (MAP) in midpregnancy for the development of hypertensive complications in later pregnancy.

Effects of different inspired oxygen fractions on lipid peroxidation during general anaesthesia for elective Caesarean section

BACKGROUND During general anaesthesia (GA) for Caesarean section (CS), fetal oxygenation is increased by administering an inspired oxygen fraction (Fi(o(2))) of 1.0. However, it is unclear whether such high Fi(o(2)) will increase oxygen free radical activity. METHODS We randomized 39 ASA I-II parturients undergoing elective CS under GA to receive 30% (Gp 30), 50% (Gp 50), or 100% (Gp 100) oxygen with nitrous oxide and sevoflurane adjusted to provide equivalent minimum alveolar concentration. Baseline maternal arterial blood before preoxygenation and maternal arterial, umbilical arterial and venous blood at delivery were sampled for assays of the by-product of lipid peroxidation, isoprostane, and for measurement of blood gases and oxygen content. RESULTS Maternal and umbilical isoprostane concentrations were similar among the three groups at delivery, despite significantly increased maternal and fetal oxygenation in Gp 100. However, paired comparisons of maternal delivery vs baseline concentration of isoprostane showed an increase at delivery for all groups [Gp 30: mean 342 (sd 210) vs 154 (65) pg ml(-1), P=0.016; Gp 50: 284 (129) vs 156 (79) pg ml(-1), P=0.009; Gp 100: 332 (126) vs 158 (68) pg ml(-1), P<0.001]. The magnitude of increase was similar in all three groups and independent of the Fi(o(2)) or duration after induction. CONCLUSIONS GA for CS is associated with a marked increase in free radical activity in the mother and baby. The mechanism is unclear but it is independent of the inspired oxygen in the anaesthetic mixture. Therefore, when 100% oxygen is administered with sevoflurane for GA, fetal oxygenation can be increased, without inducing an increase in lipid peroxidation.

Monoamine Oxidase A Expression Is Vital for Embryonic Brain Development by Modulating Developmental Apoptosis

Monoamine oxidases (MAO-A, MAO-B) metabolize biogenic amines and have been implicated in neuronal apoptosis. Although apoptosis is an important process in embryo development, the role of MAO isoenzymes has not been investigated in detail. We found that expression of MAO-A and MAO-B can be detected early on during embryo development. Expression levels remained constant until around midgestation but then dropped to almost undetectable levels toward birth. Similar expression kinetics were observed in the brain. Isoform-specific expression silencing of MAO-A mediated by siRNA during in vitro embryogenesis induced developmental defects, as indicated by a reduction of the crown rump length and impaired cerebral development. These alterations were paralleled by elevated serotonin levels. Similar abnormalities were observed when embryos were cultured in the presence of the MAO-A inhibitor clorgyline or when the transcriptional inhibitor of MAO-A expression R1 was overexpressed. In contrast, no such alterations were detected when expression of MAO-B was knocked down. To explore the underlying mechanisms for the developmental abnormalities in MAO-A knockdown embryos, we quantified the degree of developmental apoptosis in the developing brain. MAO-A knockdown reduced the number of apoptotic cells in the neuroepithelium, which coincided with impaired activation of caspases 3 and 9. Moreover, we observed reduced cyclin D1 levels as an indicator of impaired cell proliferation in MAO-A knockdown embryos. This data highlights MAO-A as a vital regulator of embryonic brain development.

Melamine in prenatal and postnatal organs in rats

Melamine can be transferred to fetus in utero through placenta and to infant ex utero by breast feeding. In this study, we characterized the pharmacokinetics of melamine in prenatal and postnatal organs in rats. Single bolus of melamine was administered to pregnant rats at different gestational stages and to infants at different postnatal stages. Distribution of melamine in maternal serum was about 30% higher in late pregnancy than that in early pregnancy; and it was 2 folds higher in postnatal serum in early infants in young adulthood. Distribution of melamine in all postnatal organs was higher than that in prenatal organs. Postnatal kidneys in early infants had the highest maximum concentration and the lowest clearance of melamine than the other postnatal organs. It may relate to the high vulnerability to the toxicity of melamine in this population.

Identification of hemopexin in tear film.

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.

High isoprostane level in cardinal ligament-derived fibroblasts and urine sample of women with uterine prolapse

We studied the isoprostane level, a well‐recognised biomarker of oxidative stress, from women with uterine prolapse and age‐matched female controls without prolapse. Cardinal ligament‐derived fibroblasts explanted from women with prolapse showed a significant increased level of isoprostane production (P < 0.05) compared with those derived from controls. This concurs with elevated urinary isoprostane levels identified among women with prolapse (P < 0.001) compared with controls. In addition, the matrix metalloproteinase 2 mRNA was significantly increased (P= 0.004) among women with uterine prolapse. Parallel findings of increased isoprostane in cardinal ligament and urine sample among women with prolapse suggest that oxidative stress might be involved in the development of uterine prolapse.