Bioactive lipids in pathological retinopathy.

Diabetic retinopathy is a common condition that occurs in patients with diabetes with long-standing hyperglycemia that is characterized by inappropriate angiogenesis. This pathological angiogenesis could be a sort of physiological proliferative response to injury by the endothelium. Recent studies suggested that reactive oxygen species (ROS) play a significant role in this angiogenesis. Vascular endothelial growth factor (VEGF) is a potent angiogenic growth factor that plays a significant role in diabetic retinopathy. The interaction between VEGF and ROS, and theirs in turn with pro- and anti-inflammatory cytokines and anti-inflammatory bioactive lipid molecules such as lipoxins, resolvins, protectins, and maresins is particularly relevant to understand the pathophysiology of diabetic retinopathy and develop future therapeutic interventions.

Investigations of the cytotoxicity of epigallocatechin-3-gallate against PC-3 cells in the presence of Cd2+ in vitro.

The epidemiological studies and recent data have provided convinced evidence that green tea and its major constituent epigallocatechin gallate (EGCG) might have the potential to lower the risk of cancers in humans. Metal ions, such as zinc and cadmium, which are necessary to our health, are important factors inducing many diseases including prostate cancer in the condition of absence or excess. EGCG can satisfactorily exhibit complex chemistry with metal ions because of multiple hydroxyl states, which in turn changes their bioactivities and metabolism pathways. This paper presents the results of an investigation of the cytotoxicity of EGCG against PC-3 prostate cancer cells in the presence and absence of Cd2+ in vitro. The results showed that both EGCG and Cd2+ suppressed viability and clonegenecity of PC-3 cells, and the suppression effect was enhanced when EGCG added with Cd2+. Although Cd2+ up-regulated the 67 kDa laminin receptor (67LR), which is a migration-associated protein, the cell migration ability was not significantly increased after each treatment. We also found that EGCG and Cd2+ directly interacted with mitochondrial, and the mixture of EGCG and Cd2+ (EGCG+Cd2+) significantly caused loss of the mitochondrial membrane potential, decrease of the ATP content and activation of caspase-9 compared with EGCG treated alone. Taken together, these findings suggest that Cd2+ enhanced the cytotoxicity of EGCG to PC-3 cells by up-regulating the 67LR and the mitochondria-mediated apoptosis pathway.

Comparison of effects of epigallocatechin-3-gallate on hypoxia injury to human umbilical vein, RF/6A, and ECV304 cells induced by Na(2)S(2)O(4).

Hypoxia is related to the etiology of numerous pathological disease states, such as the formation of tumors or diverse retinopathies. Epigallocatechin-3-gallate (EGCG), a potent polyphenolic antioxidant and antiangiogenic compound found in green tea, has been shown to suppress the growth of blood vessels necessary for the growth of tumors and the induction of retinopathies. However, only a few studies have been carried focusing on the protective effects of EGCG on hypoxia-induced injury of cultured endothelial cells. The present study investigated the effects of EGCG on Na(2)S(2)O(4)-induced hypoxic injury in three types of cultured endothelial cells, primary isolates of normal human umbilical vein endothelial cells (HUVECs), and two transformed endothelial cells lines, RF/6A and ECV304. Our results indicated that Na(2)S(2)O(4) inhibited the growth of HUVE, RF/6A, and ECV304 cells in a dose-dependent manner; EGCG also exerted inhibitory effects on the growth of the three cell types, but the toxicity of EGCG to HUVECs was less than to RF/6A and ECV304 cells. The viability of HUVE, RF/6A, and ECV304 cells treated with EGGC were the lowest at 24, 24, and 36 h, respectively, and the IC(50) of EGCG were 420 +/- 8.0, 125 +/- 7.1, and 75 +/- 5.1 microM, respectively. Furthermore, EGCG, an efficient nontoxic agent, protected all three cell types from Na(2)S(2)O(4)-induced hypoxia injury, providing partial protection from hypoxia-induced injury in normal endothelial cells at 100, 30, and 10 microM for HUVE, RF/6A, and ECV304 cells, respectively.

Fatty acids in tea shoots (Camellia sinensis (L.) O. Kuntze) and their effects on the growth of retinal RF/6A endothelial cell lines.

Chemo-protective effects of tea on ocular diseases were recorded in Chinese pharmacopoeia about 2000 years ago by eating tea. In the present study, contents of fatty acids (FAs) in tea shoots were determined by capillary GC; and the growth of RF/6A cells was also investigated by exposure to various representative FAs existing in tea shoots with pathologically relevant concentrations (40-500 microM) by ameliorated MTT assay and flow cytometry. Electron spin resonance (ESR) was used to measure oxygen consumption and investigate the free radical scavenging ability of linoleic acid (LA). Results showed that the most abundant long chain FAs were palmitic, linoleic, and alpha-linolenic acid in tea shoots; some RF/6A cells became suspended in culture medium treated by a high dose of both saturated and unsaturated FAs, but no apoptosis was observed. Moreover, it seemed that those FAs with different structure had various effects on the cell proliferation at their relatively low concentrations, LA expressed antioxidant activity in this study, which might be an important mechanism on the protection of eyes.

Effects of interactions of EGCG and Cd(2+) on the growth of PC-3 cells and their mechanisms.

The preventive and therapeutic effects of a major component of catechins of green tea, epigallocatechin-3-gallate (EGCG), on prostate cancer have been demonstrated in many studies. It is well known that metal ions are necessary for human health, but an imbalance in metal ions metabolism can lead to many diseases including prostate cancer. Understanding the interactions of EGCG with metal ions might elucidate its mechanism in preventing and curing prostate cancer. The present study focused on the effects of Cd(2+) and EGCG on the growth of androgen-insensitive prostate cancer cell PC-3 investigated by MTT assay, the effects of EGCG and Cd(2+) on absorption of Cd(2+) and Zn(2+) by PC-3 cells were detected by atomic absorption spectroscopy (AAS), and the interactions of EGCG with Cd(2+) were determined by distribution coefficient and UV-Vis spectroscopy detection. The results showed that Cd(2+) suppressed viability of PC-3 cells in concentration- and time-dependent manner, and EGCG enhanced the effect of Cd(2+) on PC-3 cells. EGCG was shown to decrease the absorption Cd(2+) and increase the absorption of Zn(2+) by PC-3 cells, while the effects of Cd(2+) on the absorption of Cd(2+) and Zn(2+) were opposite to that of EGCG. In the presence of both EGCG and Cd(2+), absorption of Cd(2+) and Zn(2+) by PC-3 cells was dependent on concentrations of EGCG, Cd(2+) and its order of addition. Results from the distribution coefficient determination and UV-Vis spectroscopy analysis indicated that Cd(2+) might affect conformation of EGCG, while no complex of EGCG with Cd(2+) was observed in the system.

Effects of astaxanthin on oxidative stress induced by Cu2+ in prostate cells.

Astaxanthin (AST), a carotenoid molecule extensively found in marine organisms and increasingly used as a dietary supplement, has been reported to have beneficial effects against oxidative stress. In the current paper, the effects of AST on viability of prostate cells were investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay; cell apoptosis and intracellular reactive oxygen species (ROS) levels were determined by flow cytometry; the mitochondrial membrane potential (MMP) was measured by fluorospectrophotometer; and activities of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were evaluated by a detection kit. The results show that copper ion (Cu2+) induced apoptosis, along with the accumulation of intracellular ROS and MDA, in both prostate cell lines (RWPE-1 and PC-3). AST treatments could decrease the MDA levels, increase MMP, and keep ROS stable in RWPE-1 cell line. An addition of AST decreased the SOD, GSH-Px, and CAT activities in PC-3 cell line treated with Cu2+, but had a contrary reaction in RWPE-1 cell lines. In conclusion, AST could contribute to protecting RWPE-1 cells against Cu2+-induced injuries but could cause damage to the antioxidant enzyme system in PC-3 cells.

Dietary Guidelines for Chinese Residents (2016): comments and comparisons.

A high quality diet is believed to play a functional role in promoting the healthy growth of mankind and preventing many kinds of chronic degenerative diseases, including cancer, cardiovascular disease, diabetes, and obesity. Adherence to a high quality diet has been strongly associated with a lower risk of mortality. To help promote healthy lifestyles and physical strength, the Chinese government has produced a new revised version of the Dietary Guidelines for Chinese Residents (2016) and the Chinese Food Pagoda, as guidance for dietary intake among its population. Similarly, the Japanese government has produced the Japanese Food Guide Spinning Top Model, and the US government has recently published revised dietary recommendations in its 2015-2020 eighth edition of Dietary Guidelines for Americans. The evidence from all respective cohort studies involved in producing these guidelines shows a reduced risk of many chronic diseases and mortality if the guidelines are followed. All scientific findings support encouraging the general population to consume a broad variety of food on the basis of nutrient and food intakes in order to prevent deficiency diseases and a surplus of energy and nutrients, and recommend daily physical activity for health promotion.

Molecularly imprinted polymers as the extracted sorbents of clenbuterol ahead of liquid chromatographic determination.

A pre-treatment methodology for clenbuterol hydrochloride (CLEN) isolation and enrichment in a complex matrix environment was developed through exploiting molecularly imprinted polymers (MIPs). CLEN-imprinted polymers were synthesized by the combined use of ally-ß-cyclodextrin (ally-ß-CD) and methacrylic acid (MAA), allyl-ß-CD and acrylonitrile (AN), and allyl-ß-CD and methyl methacrylate (MMA) as the binary functional monomers. MAA-linked allyl-ß-CD MIPs (M-MAA) were characterized by Fourier transform-infrared (FT-IR) spectroscopy and a scanning electron microscope (SEM). Based upon the results, M-MAA polymers generally proved to be an excellent selective extraction compared to its references: AN-linked allyl-ß-CD MIPs (M-AN) and MMA-linked allyl-ß-CD MIPs (M-MMA). M-MAA polymers were eventually chosen to run through a molecularly imprinted solid-phase extraction (MISPE) micro-column to enrich CLEN residues spiked in pig livers. A high recovery was achieved, ranging from 91.03% to 96.76% with relative standard deviation (RSD) ≤4.45%.

Cytotoxicity of epigallocatechin-3-gallate to LNCaP cells in the presence of Cu2+.

Epigallocatechin-3-gallate (EGCG) has shown remarkably anti-cancer activity, with its bioactivity being related to reactive conditions, such as pH and metal ions. The present study investigated the degradation of EGCG and its effect on prostate cancer cell in the presence of Cu2+. EGCG was incubated with prostate cancer cells, LNCaP, pretreated with or without Cu2+. EGCG in F-12 medium was quantified using HPLC and the viability of cells was assessed by gel electrophoresis, flow cytometry, and electron microscope. The results of HPLC showed that EGCG degraded completely within 12 h in F-12 medium with or without Cu2+. Gel electrophoresis and flow cytometry did not detect apoptosis of LNCaP cells when they were incubated with EGCG. Electron microscopy examination revealed that EGCG-Cu2+ complex led to damage of cytoplasm membrane in LNCaP cells. It was speculated that not EGCG, but its oxide and complex with Cu2+, are the bioactive components responsible for its cytotoxicity to LNCaP prostate cancer cells.

Growth inhibition of prostate cancer cells by epigallocatechin gallate in the presence of Cu2+.

Green tea is an effective chemopreventive agent to human prostate cancer adenoma (PCA). Epigallocatechin gallate (EGCG) inhibited the growth of PCA cells and induced apoptosis. Cu(2+) is a trace element necessary to our health. Many studies proved that bioactivity of EGCG is altered in the presence of Cu(2+). We investigated the effects of EGCG on PCA cells in the presence of Cu(2+). Also, we explored potential mechanisms via measurement of the relative chemiluminescence of growth medium for PCA cells. Chemiluminscence can be an indication of free radicals. Our test results showed that the addition of EGCG and Cu(2+) to the growth medium decreased the relative viability of androgen-sensitive and androgen-insensitive human prostate cancer cells. However, the effects of EGCG on PCA cells depended on (1) the relative concentrations of added EGCG and Cu(2+) and (2) their order of addition. Our results indicated that few free radicals may be generated in vitro. If so, free radicals generated intracellularly may be a major factor behind apoptosis and growth inhibition observed in the PCA cells. Thus, EGCG might exert its effects intracellularly.

Interaction of catechins with aluminum in vitro.

Tea is one of the most popular beverages, consumed by over two thirds of the world's population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum's known adverse effect on human health. Investigation of the interactions of catechins with Al(3+) showed that during the interaction of catechins with Al(3+), the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C's at 278 nm changed little. The ratio of Al(3+) to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al(3+) was the same as that of EGCG, with a little difference for EC. When the ratio of Al(3+) to EC was <1, the complex in ratio was 1:2, but, the complex polymerized when the ratio of Al(3+) to EC was >1. It was found that the ratio of Al(3+) to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake.

Effects of fish oil with a high content of n-3 polyunsaturated fatty acids on mouse gut microbiota.

BACKGROUND AND AIMS: Many studies show that fish oil with high content of n-3 polyunsaturated fatty acids (PUFAs) plays an important role in human health and disease. But the effects of fish oil with high content of PUFAs on gut microbiota, which are also known play a significant role in several human diseases, is not clear. In the present study we evaluated the effects of fish oil with high content of n-3 PUFAs on gut microbiota. METHODS: Changes in gut microbiota in ICR mice after supplementation of fish oil (containing eicosapentaenoic acid and docosahexaenoic acid: ∼40 and 27% respectively) for 15 days was characterized using the hypervariable V3 region of the 16 rRNA gene-based polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) profiling, DNA sequencing, and phylogenetic analysis techniques. RESULTS: Fish oil treatment resulted in a decrease in Helicobacter, Uncultured bacterium clone WD2_aaf07d12 (GenBank: EU511712.1), Clostridiales bacterium, Sphingomonadales bacterium and Pseudomonas species Firmicutes, and several uncultured bacteria. CONCLUSIONS: Fish oil with a high content of n-3 PUFAs are capable of producing significant changes in the gut microbiota that may, at least in part, explain the health benefits or injury induced by fish oil use.

Effect of α-linolenic acid on streptozotocin-induced diabetic retinopathy indices in vivo.

BACKGROUND AND AIMS: Both oxidative stress and inflammation play a significant role in the pathobiology of diabetic retinopathy. Increased consumption of polyunsaturated fatty acids (PUFAs) may prevent or postpone the occurrence of diabetic retinopathy. Hence, the effect of α-linolenic acid (ALA), an essential fatty acid, on oxidative stress, inflammatory indices and production of vascular endothelial growth factor (VEGF) in streptozotocin-induced diabetic retinopathy indices in vivo was studied. METHODS: Serum and retina concentrations of vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), plasma and retina concentrations of lipid peroxides and antioxidant enzymes were estimated in streptozotocin (STZ)-induced diabetic animals. RESULTS: STZ-induced diabetic rats had significantly higher levels of VEGF in the serum and retina and IL-6 in the serum, whereas BDNF was lower in the serum, all of which reverted to near normal in ALA-treated diabetic animals. STZ treatment decreased serum glutathione peroxidase levels, which was restored to normal by both pre- and post-ALA treatment groups. CONCLUSIONS: STZ-induced changes in serum glutathione peroxidase, BDNF, VEGF and IL-6 that reverted to near control by ALA treatment, especially in ALA + STZ group, lending support to the concept that both oxidative stress and inflammation participate in DR and ALA treatment is of benefit in its prevention.

Production of conjugated linoleic acids by Lactobacillus plantarum strains isolated from naturally fermented Chinese pickles.

Naturally fermented pickles harbour many lactic acid bacteria (LAB). Forty-three LAB strains with conjugated linoleic acid (CLA)-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, lp15 identified as Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability (26.1% conversion) at 48 h in de Man Rogosa Sharpe (MRS) broth in the presence of 100 µg/ml of linoleic acid (LA). Compared to other strains, L. plantarum strain lp15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 µg/ml. This strain converted about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA (9-CLA) and trans-10, cis-12 CLA (10-CLA)], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by lp15 remained stable between 100 to 600 µg/ml LA levels in the medium, it dropped sharply at 1000 µg/ml. Taken together, the lp15 strain displayed relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing the CLA content in food-sources like pickles.

Colorectal cancer cell growth inhibition by linoleic acid is related to fatty acid composition changes.

Polyunsaturated fatty acids (PUFAs) possess anti-cancer action both in vitro and in vivo. In the present study, we detected cell viability with methyl thiazolyl tetrazolium (MTT) assay and cell membrane permeability with propidium iodide (PI) fluorescence dyeing, and calculated cell membrane fluidity change as fluorescence anisotropy. Fatty acid content in cells was measured by gas chromatography/mass spectroscopy (GC/MS), and the relationship between fatty acid composition and cell viability was studied. We observed that n-6 PUFA linoleic acid (LA) inhibited tumor cell growth at high concentrations (≥300 µmol/L), while low concentrations (100-200 µmol/L) seemed to promote cell proliferation. Analyses of cell membrane permeability, cell membrane fluidity, and cell fatty acid composition suggested that the anti-cancer action of LA could be related to changes in the ratio of n-6 to n-3 PUFAs. We observed that pre-incubation of cancer cells with 100 µmol/L LA for 24 h enhanced cell sensitivity to the cytotoxic action of LA, whereas undifferentiated cell line LoVo seemed to have a distinct path in LA-induced death. These results showed that one of the mechanisms by which supplementation of LA induces cancer cell death could be altering the ratio of n-6/n-3 PUFAs, and this may be related to cell differentiation status.

Effect of laminin tyrosine-isoleucine-glycine-serine-arginine peptide on the growth of human prostate cancer (PC-3) cells in vitro.

The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of beta1 chain, is known to inhibit tumor growth and metastasis. In the present study, we observed that YIGSR not only inhibited the growth and migration of prostate cancer cells in a dose-dependent manner but also decreased mitochondrial membrane potential, inhibited ATP synthesis and increased caspase-9 activity. Investigation into the interaction of YIGSR with 67LR, the receptor for laminin and polyphenol (-) epigallocatechin-3-gallate (EGCG) employing MVD (Molegro Virtual Docker, an integrated platform for predicting protein ligand interactions), revealed that the binding site of YIGSR was the same as that of EGCG that explains as to why YIGSR is able to inhibit the cytotoxicity of EGCG against PC-3 cells.

Epigallocatechin-3-gallate affects the growth of LNCaP cells via membrane fluidity and distribution of cellular zinc.

OBJECTIVE: To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn(2+), in human prostate carcinoma LNCaP cells. METHODS: We examined changes in cellular morphology and membrane fluidity of LNCaP cells, distribution of cellular zinc, and the incorporated portion of EGCG after treatments with EGCG, Zn(2+), and EGCG+Zn(2+). RESULTS: We observed an alteration in cellular morphology and a decrease in membrane fluidity of LNCaP cells after treatment with EGCG or Zn(2+). The proportion of EGCG incorporated into liposomes treated with the mixture of EGCG and Zn(2+) at the ratio of 1:1 was 90.57%, which was significantly higher than that treated with EGCG alone (30.33%). Electron spin resonance (ESR) studies and determination of fatty acids showed that the effects of EGCG on the membrane fluidity of LNCaP were decreased by Zn(2+). EGCG accelerated the accumulation of zinc in the mitochondria and cytosol as observed by atomic absorption spectrometer. CONCLUSION: These results show that EGCG interacted with cell membrane, decreased the membrane fluidity of LNCaP cells, and accelerated zinc accumulation in the mitochondria and cytosol, which could be the mechanism by which EGCG inhibits proliferation of LNCaP cells. In addition, high concentrations of Zn(2+) could attenuate the actions elicited by EGCG.

[Growth inhibition of prostate cancer cells by epigallocatechin-3-gallate in the presence of Zn2+ in vitro].

In this paper, the cytotoxicity of EGCG against PC-3 prostate cancer cells and its molecular mechanism in the presence and absence of Zn2+ in vitro were investigated. The results showed that both EGCG and Zn2+ suppressed clonegenecity of PC-3 cells, and the suppression effect was enhanced in the coexist system of EGCG and Zn2+. MMP-9 is thought to play a significant role in cancer cell migration and invasion. In the present paper, the results showed that EGCG suppressed the activity of MMP-9 in PC-3 cells in the presence of Zn2+, as a result, migration ability of the cells was significantly decreased.

Free Zn(2+) enhances inhibitory effects of EGCG on the growth of PC-3 cells.

Epigallocatechin-3-gallate (EGCG), a major component of green tea, has both preventive and therapeutic beneficial actions in prostate cancer. In the present study, we compared the growth inhibitory effects and the antioxidant and ability to modify cell membrane permeation of zinc-EGCG complex and Zn2+/EGCG mixture on androgen-insensitive prostate cancer (PC-3) cells. It was noted that free Zn2+ enhanced the growth inhibitory effects of EGCG on PC-3 cells at 160 micromol/L concentration,whereas zinc-EGCG complex was ineffective. EGCG showed potent free radical scavenging ability in the presence of Zn2+. EGCG in the presence of Zn2+ was more effective than EGCG alone in enhancing the permeability of the cell membrane, whereas zinc-EGCG complex had no effect on PC-3 cell membrane permeability. These results indicate that though Zn2+ enhanced the action of EGCG on PC-3 cells, zinc-EGCG complex is highly unlikely to be formed in the presence of Zn2+ and EGCG to explain the potentiating action of Zn2+ on the growth inhibitory property of EGCG on PC-3 cells.