Haining Yu

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.

Linoleic acid suppresses colorectal cancer cell growth by inducing oxidant stress and mitochondrial dysfunction

Some polyunsaturated fatty acids (PUFAs), if not all, have been shown to have tumoricidal action, but their exact mechanism(s) of action is not clear. In the present study, we observed that n-6 PUFA linoleic acid (LA) inhibited tumor cell growth at high concentrations (above 300 μM); while low concentrations (100-200 μM) promoted proliferation. Analysis of cell mitochondrial membrane potential, reactive oxygen species (ROS) formation, malondialdehyde (MDA) accumulation and superoxide dismutase (SOD) activity suggested that anti-cancer action of LA is due to enhanced ROS generation and decreased cell anti-oxidant capacity that resulted in mitochondrial damage. Of the three cell lines tested, semi-differentiated colorectal cancer cells RKO were most sensitive to the cytotoxic action of LA, followed by undifferentiated colorectal cancer cell line (LOVO) while the normal human umbilical vein endothelial cells (HUVEC) were the most resistant (the degree of sensitivity to LA is as follows: RKO > LOVO > HUVEC). LA induced cell death was primed by mitochondrial apoptotic pathway. Pre-incubation of cancer cells with 100 μM LA for 24 hr enhanced sensitivity of differentiated and semi-differentiated cells to the subsequent exposure to LA. The relative resistance of LOVO cells to the cytotoxic action of LA is due to a reduction in the activation of caspase-3. Thus, LA induced cancer cell apoptosis by enhancing cellular oxidant status and inducing mitochondrial dysfunction.

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.中文概要高质量的膳食在促进人类健康成长和防治包括癌 症、心血管疾病、糖尿病和肥胖在内的多种慢性 疾病中起着重要的作用。坚持高质量的膳食能有 效地降低死亡率。为了帮助形成健康的生活方 式,增强体质,中国政府发布了新的中国居民膳 食指南(2016)和膳食宝塔,用来指导居民膳食 的摄入。同样,日本政府早期发布了日本膳食指 南陀螺模型,美国政府最近也出版了修订后的第 八版美国居民膳食指南(2015–2020)。与指南 相关的同期证据表明,遵循指南进行膳食指导, 许多慢性疾病的发病率和死亡率都会降低。所有 的科学发现支持鼓励居民在保证营养和食物摄 入的基础上消耗各种各样的食物以防止营养缺 乏疾病以及能量和营养过剩,并且建议进行日常 活动来保持身体健康。

Polyunsaturated fatty acids trigger apoptosis of colon cancer cells through a mitochondrial pathway

Introduction Colorectal cancer is common in developed countries. Polyunsaturated fatty acids (PUFAs) have been reported to possess tumoricidal action, but the exact mechanism of their action is not clear. Material and methods In the present study, we studied the effect of various n-6 and n-3 fatty acids on the survival of the colon cancer cells LoVo and RKO and evaluated the possible involvement of a mitochondrial pathway in their ability to induce apoptosis. Results It was observed that n-3 α-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid (ALA, EPA and DHA respectively) and n-6 linoleic acid, gamma-linolenic acid and arachidonic acid (LA, GLA and AA respectively) induced apoptosis of the colon cancer cells LoVo and RKO at concentrations above 120 μM (p < 0.01 compared to control). The semi-differentiated colon cancer cell line RKO was more sensitive to the cytotoxic action of PUFAs compared to the undifferentiated colon cancer cell line LoVo. PUFA-treated cells showed an increased number of lipid droplets in their cytoplasm. PUFA-induced apoptosis of LoVo and RKO cells is mediated through a mitochondria-mediated pathway as evidenced by loss of mitochondrial membrane potential, generation of ROS, accumulation of intracellular Ca2+, activation of caspase-9 and caspase-3, decreased ATP level and increase in the Bax/Bcl2 expression ratio. Conclusions PUFAs induced apoptosis of colon cancer cells through a mitochondrial dependent pathway.

State-of-the-art applications of cyclodextrins as functional monomers in molecular imprinting techniques: a review.

As a versatile tool in separation science, cyclodextrins and their derivatives, known as emerging functional monomers, have been used extensively in molecular imprinting techniques. The attributes of cyclodextrins and their derivatives are widely known to form host-guest inclusion complex processes between the polymer and template. The exploitation of the imprinting technique could produce a product of molecularly imprinted polymers, which are very robust with long-term stability, reliability, cost-efficiency, and selectivity. Hence, molecularly imprinted polymers have gained popularity in chemical separation and analysis. Molecularly imprinted polymers containing either cyclodextrin or its derivatives demonstrate superior binding effects for a target molecule. As noted in the previous studies, the functional monomers of cyclodextrins and their derivatives have been used in molecular imprinting for selective separation with a wide range of chemical compounds, including steroidals, amino acids, polysaccharides, drugs, plant hormones, proteins, pesticides, and plastic additives. Therefore, the main goal of this review is to illustrate the exotic applications of imprinting techniques employing cyclodextrins and their derivatives as single or binary functional monomers in synthesizing molecularly imprinted polymers in areas of separation science by reviewing some of the latest studies reported in the literature.

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.

Free Zn2+ 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.

Urinary microbiota in patients with prostate cancer and benign prostatic hyperplasia

Introduction Inflammation is associated with promotion of the initiation of various malignancies, partly due to bacterial infection-induced microenvironmental changes. However, the exact association between microbiota in urine, seminal fluid and the expressed prostatic secretions and benign prostatic hypertrophy and prostate cancer is not clear. Material and methods In the present study, we investigated the type of microbiota in the expressed prostatic secretions (EPS) of patients with prostate cancer and benign prostatic hyperplasia (BPH) by the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method using universal bacterial primers. In order to understand the possible association between various bacteria and prostate cancer, quantitative real-time PCR assay was performed to quantify the amount of strains of bacteria in urine, EPS and seminal fluid. Results The prostate cancer group had a significantly increased number of Bacteroidetes bacteria, Alphaproteobacteria, Firmicutes bacteria, Lachnospiraceae, Propionicimonas, Sphingomonas, and Ochrobactrum, and a decrease in Eubacterium and Defluviicoccus compared to the BPH group. The number of Escherichia coli in the prostate cancer group was significantly decreased in urine and increased in the EPS and seminal fluid, while the number of Enterococcus was significantly increased in the seminal fluid with little change in urine and EPS. Conclusions Based on these results, we suggest that there are significant changes in the microbial population in EPS, urine and seminal fluid of subjects with prostate cancer and BPH, indicating a possible role for these bacteria in these two conditions.

Mechanism of Free Zn(2+) Enhancing Inhibitory Effects of EGCG on the Growth of PC-3 Cells: Interactions with Mitochondria

Green tea and its major constituent epigallocatechin gallate (EGCG) are known for their chemopreventive effects including those against prostate cancer, which could be mediated by metal ions. Zn2+ is an essential trace element that is required for human health and plays an important role in the normal function of the prostate gland. In the present study, the effect of EGCG on cell membrane and mitochondria of PC-3 (prostate carcinoma) cells in the presence and absence of Zn2+ was studied. These studies revealed that EGCG, Zn2+, or EGCG + Zn2+ affected the morphology of PC-3 cells and induced apoptosis in PC-3 cells. It was observed that effects of treatment with EGCG, Zn2+, or EGCG + Zn2+on mitochondria showed EGCG + Zn2+ > Zn2+ > EGCG, including cytochrome C release from the intermembrane space into the cytosol, inhibited the synthesis of ATP, loss of mitochondrial membrane potential, and activation of caspase-9. However, the order of effect on depressing membrane fluidity of PC-3 cells was EGCG > EGCG + Zn2+ > Zn2+. In summary, these findings suggest that EGCG, Zn2+, and EGCG + Zn2+ induce necrosis or apoptosis of PC-3 cells through mitochondria-mediated apoptotic pathway and free Zn2+-enhanced effects of EGCG on PC-3 cells due to its interactions with mitochondria.

Growth Inhibitory Effect of Polyunsaturated Fatty Acids (PUFAs) on Colon Cancer Cells via Their Growth Inhibitory Metabolites and Fatty Acid Composition Changes

Background Colorectal cancer is common. Polyunsaturated fatty acids (PUFAs) exert growth-inhibitory and pro-apoptotic effects on colon cancer cells. Metabolites of PUFAs such as prostaglandins (PGs), leukotrienes (LTs) and lipoxins (LXs) play a significant role in colon cancer. Methods Human colon cancer LoVo and RKO cells were cultured with different concentration of PUFAs and 5-fluorouracil (5-FU) in vitro. Cell morphological changes, fatty acid composition, formation of PGE2, LTB4 and LXA4 and expression of COX-2, ALOX5, PGD synthase (PGDS), microsomal prostaglandin E synthase (mPGES) were assessed in LoVo and RKO cells when supplemented with PUFAs and 5-FU. Results PUFAs and 5-FU inhibited growth of LoVo and RKO cells to the same extent at the doses used and produced significant alterations in their shape. As expected, higher concentrations of supplemented PUFAs were noted in the cells compared to control. LA, GLA, AA, ALA and EPA supplementation to LoVo cells suppressed production of PGE2, LTB4,and ALOX5, mPGES expression, but enhanced that of LXA4; whereas DHA enhanced PGE2 and LXA4 synthesis but decreased LTB4 formation and COX-2, ALOX5, mPGES expression. In contrast, 5-FU enhanced formation of PGE2, LTB4 and mPGES expression, but suppressed LXA4 synthesis and COX-2 expression. PGE2, LTB4 synthesis and ALOX5 expression was suppressed by LA, GLA, ALA and DHA; whereas AA, EPA and 5-FU enhanced PGE2 but paradoxically AA decreased and EPA and 5-FU enhanced LTB4 synthesis in RKO cells. All the PUFAs tested enhanced, while 5-FU decreased LXA4 formation in RKO cells; whereas GLA, AA, and 5-FU augmented while LA, ALA, EPA and DHA enhanced COX-2 expression in RKO cells. Conclusions Tumoricidal action of PUFAs on colorectal LoVo and RKO cancer cells in vitro was associated with increased formation of LXA4, decreased synthesis of PGE2 and LTB4 and suppressed expression of COX-2, ALOX5, mPGES, whereas 5-FU produced contrasting actions on these indices.