Coffee polyphenols exert hypocholesterolemic effects in zebrafish fed a high-cholesterol diet

Coffee prevents IQ-induced liver damage by regulating oxidative stress, inflammation, endoplasmic reticulum stress, autophagy, apoptosis, and the MAPK/NF-κB signaling pathway in zebrafish

2-Amino-3-methylimidazole[4,5-f]quinoline (IQ), one of heterocyclic amines (HCAs) produced in proteinaceous foods upon heating, is recognized as a carcinogen. Previous studies have confirmed that IQ intake can cause liver damage in zebrafish. In the current study, we revealed the protective effects of coffee against IQ-induced liver damage. We exposed one-month-old wild-type zebrafish to IQ (80 ng/mL) and coffee at 50 mg/L, 100 mg/L, and 300 mg/L for 35 days. Markers of oxidative stress, inflammation, endoplasmic reticulum stress (ERS), autophagy, and apoptosis in the liver were assessed to explore the potential mechanisms of the protective effects. The results showed that coffee effectively improved IQ-induced liver damage by reducing ALT, AST, TC, TG, and LDL-C levels, increasing HDL-C level, and restoring hepatic morphology. Moreover, coffee showed an antioxidative effect by increasing GSH, GSH-Px, GST, CAT, and SOD levels and attenuating ROS and MDA contents. Additionally, coffee reduced the NO, iNOS, TNF-α, IL-6, IL-1β, and IL-12 expression levels, presenting an anti-inflammatory effect. Furthermore, coffee protected against ERS, autophagy dysfunction, and apoptosis by decreasing the GRP78, CHOP, and p62 while increasing the Atg5-Atg12, Beclin1, LC3-II, and Bcl-2 expression levels. TUNEL results showed that coffee rescued IQ-induced hepatocyte apoptosis. In addition, coffee interrupted the MAPK/NF-κB signaling pathway by suppressing the phosphorylation expressions of JNK, ERK, p38, p65, and IκB. These findings indicated that coffee prevents IQ-induced liver damage with antioxidative, anti-inflammatory, anti-ERS, anti-apoptotic, and pro-autophagic effects, thus to serve as a functional beverage with potential health benefits.

Zebrafish: A Model Deciphering the Impact of Flavonoids on Neurodegenerative Disorders

Over the past century, advances in biotechnology, biochemistry, and pharmacognosy have spotlighted flavonoids, polyphenolic secondary metabolites that have the ability to modulate many pathways involved in various biological mechanisms, including those involved in neuronal plasticity, learning, and memory. Moreover, flavonoids are known to impact the biological processes involved in developing neurodegenerative diseases, namely oxidative stress, neuroinflammation, and mitochondrial dysfunction. Thus, several flavonoids could be used as adjuvants to prevent and counteract neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Zebrafish is an interesting model organism that can offer new opportunities to study the beneficial effects of flavonoids on neurodegenerative diseases. Indeed, the high genome homology of 70% to humans, the brain organization largely similar to the human brain as well as the similar neuroanatomical and neurochemical processes, and the high neurogenic activity maintained in the adult brain makes zebrafish a valuable model for the study of human neurodegenerative diseases and deciphering the impact of flavonoids on those disorders.

Modulation of Antioxidant Defense in Farmed Rainbow Trout (Oncorhynchus mykiss) Fed with a Diet Supplemented by the Waste Derived from the Supercritical Fluid Extraction of Basil (Ocimum basilicum)

Phytotherapy is based on the use of plants to prevent or treat human and animal diseases. Recently, the use of essential oils and polyphenol-enriched extracts is also rapidly increasing in the aquaculture sector as a means of greater industrial and environmental sustainability. Previous studies assessed the antibacterial and antiparasitic effects of these bioactive compounds on fish. However, studies on the modulation of oxidative stress biomarkers are still scant to date. Thus, in this study, the modulation of antioxidant defense against oxidative stress exerted by fish diets supplemented with a basil supercritical extract (F1-BEO) was assessed in rainbow trout Oncorhynchus mykiss. The F1-BEO extracted with supercritical fluid extraction was added to the commercial feed flour (0.5, 1, 2, 3% w/w) and mixed with fish oil to obtain a suitable compound for pellet preparation. Fish were fed for 30 days. The levels of stress biomarkers such as superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase, glyoxalase I, glyoxalase II, lactate dehydrogenase, glutathione and malondialdehyde showed a boost in the antioxidant pathway in fish fed with a 0.5% F1-BEO-supplemented diet. Higher F1-BEO supplementation led to a failure of activity of several enzymes and the depletion of glutathione levels. Malondialdehyde concentration suggests a sufficient oxidative stress defense against lipid peroxidation in all experimental groups, except for a 3% F1-BEO-supplemented diet (liver 168.87 ± 38.79 nmol/mg prot; kidney 146.86 ± 23.28 nmol/mg prot), compared to control (liver 127.76 ± 18.15 nmol/mg prot; kidney 98.68 ± 15.65 nmol/mg prot). Our results suggest supplementing F1-BEO in fish diets up to 0.5% to avoid potential oxidative pressure in farmed trout.

Effect of Emodin on Hyperlipidemia and Hepatic Lipid Metabolism in Zebrafish Larvae Fed a High-Cholesterol Diet

Hyperlipidemia (HLP) is a complex pathological condition results from lipid metabolism disorder, which is closely related to obesity, atherosclerosis and steatohepatitis. Emodin (EM), a natural anthraquinone, exhibits prominent hypolipidemic effects. However, its exact mechanism is still unclear. In this study, we successfully established hyperlipidemic zebrafish model induced by 4 % high-cholesterol diet (HCD) for 10 days and explored the anti-hyperlipidemic roles and underlying mechanisms of EM. The results indicated that EM attenuated the mortality and body mass index (BMI) of zebrafish with HLP, and ameliorated abnormal lipid levels involved in TC, TG, LDL-C and HDL-C levels. Besides, EM effectively reduced lipid accumulation in blood vessels and liver, alleviated hepatic histological damage, and inhibited vascular neutrophil inflammation. Finally, the mRNA expression of molecules related to lipid metabolism were studied by using real-time quantitative polymerase chain reaction (RT-qPCR) to investigated the underlying mechanism. Further results found that treatment with EM up-regulated AMPKα, LDLR, ABCA1 and ABCG1, and down-regulated SREBP-2, PCSK9 and HMGCR expression. In conclusion, EM showed a prominent mitigative effect on lipid metabolism disorder in zebrafish larvae with HCD-stimulated HLP, which was associated with the enhancement of LDL-C uptake and reverse cholesterol transport, and inhibition of cholesterol synthesis.

The effects of co-administration of artichoke leaf extract supplementation with metformin and vitamin E in patients with nonalcoholic fatty liver disease: A randomized clinical trial

Medicinal plants are widely used as a complementary therapy to treat complex diseases, such as nonalcoholic fatty liver disease (NAFLD). Therefore, this study was done to investigate the effect of co-administration of artichoke leaf extract supplement (ALES) with conventional medicines on patients with NAFLD. The clinical trial was based on patients randomly divided into three groups involving metformin-vitamin E (ME), metformin-ALES (MA), and vitamin E-ALES (EA). The effectiveness of treatment in the treated groups was evaluated using liver ultrasonography and biochemical markers. After 12 weeks of treatment, the results showed that the rate of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was significantly reduced within all the study groups (p < .05). Liver ultrasonographic findings revealed that the rate of fat accumulation in liver of patients was decreased significantly within all the study groups and it was increased in the subjects with grade 0 fatty liver (without fat accumulation) in the MA and EA groups by 23.3 and 17.2%, respectively. In summary, the results of the present study showed that the concomitant use of ALES with metformin and vitamin E can have beneficial effects on amelioration of complications in patients with NAFLD. However, larger-scale clinical trial studies are required in this regard.

Anti-hypercholesterolemic Effect of Berbamine Isolated from Rhizoma Coptidis in Hypercholesterolemic Zebrafish Induced by High-Cholesterol Diet

The anti-hypercholesterolemic effect of berbamine (BBM) isolated from Rhizoma Coptidis (RC) was investigated in hypercholesterolemic zebrafish model induced by high-cholesterol (HC) diet. Zebrafish embryo assay revealed no significant difference in morphology and cell death with the treatment of BBM less than 20 μg/mL. In zebrafish larvae, the fluorescently labeled cholesterol in caudal artery was reduced dose-dependently after BBM treatment. For adult zebrafish, administration of 0.2% BBM exhibited a significant decrease in plasma total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-c) levels by 37%, 38% and 28%, respectively, along with a fall in lipid content in liver. Further investigation suggested that the mRNA expression of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and microsomal triglyceride transfer protein (MTP) in liver were down-regulated and the transcription levels of liver gene low-density lipoprotein receptor (LDLR) and cytochrome P450 polypeptide 1a of subfamily A of family 7 (CYP7A1a) were significantly up-regulated with BBM treatment. Histological study showed that BBM can alleviate hepatic steatosis induced by HC diet. These data suggested that BBM has anti-hypercholesterolemic and hepatoprotective effects. The mechanism probably related to the up-regulation of cholesterol transport and bile acid synthesis as well as inhibition of cholesterol synthesis and lipoprotein assembly or secretion.

Fish Oil Suppresses Body Fat Accumulation in Zebrafish

Zebrafish is an often used model of vertebrate lipid metabolism. In this article, we examined the effects of diets rich in fish oil, a dietary fat that has been shown to have antiobesity effects in mammals, or lard on body fat accumulation in zebrafish. Adult female zebrafish were fed a high-fat diet containing 20% (w/w) fish oil or lard for 4 weeks. Fish in the fish oil diet group had less body fat accumulation compared with those in the lard diet group. In the intestine, expression of genes for the alpha (hadhaa) and beta (hadhb) subunits of the beta-oxidation enzyme hydroxyacyl-Coenzyme A dehydrogenase/3-ketoacyl-Coenzyme A thiolase/enoyl-Coenzyme A hydratase was significantly increased in the fish oil diet group compared with the lard diet group (p < 0.05). In the liver, expression of the gene for fatty acid synthase (fasn) was significantly decreased in the fish oil diet group compared with the lard diet group (p < 0.05). These results suggest that the mechanisms underlying the antiobesity effect of fish oil are similar in zebrafish and mammals.

Effect of Dietary Purified Xanthohumol from Hop (Humulus lupulus L.) Pomace on Adipose Tissue Mass, Fasting Blood Glucose Level, and Lipid Metabolism in KK-Ay Mice

We previously showed that xanthohumol-rich hop extract (XRHE, ~18% xanthohumol) exerts anti-obesity effects in rats fed a high-fat diet through regulation of fatty acid metabolism. In this study, we examined the effects of dietary purified xanthohumol from XRHE (PX, ~91.9% xanthohumol) in KK-Ay mice in order to understand the anti-obesity effects of xanthohumol alone because XRHE contains 82% unknown compounds. Dietary consumption of PX significantly inhibited an increase in the visceral fat weight of mice compared to those fed control diet without PX. Plasma leptin level was significantly lower in the PX-fed group than in the control group. Dietary PX lowered hepatic fatty acid synthesis by down-regulation of SREBP1c mRNA expression in the liver. On the other hand, fatty acid β-oxidation in the liver was promoted by dietary PX through the up-regulation of PPARα mRNA expression. Moreover, the fecal levels of fatty acids and carbohydrates increased by dietary PX. PX inhibited lipase or α-amylase activity in vitro. Thus, we found that PX may exert anti-obesity effects through the regulation of lipid metabolism and inhibition of intestinal fat and carbohydrate absorption, and that xanthohumol alone may exert anti-obesity effects.

A ruthenium derivative of quercetin with enhanced cholesterol-lowering activity

A ruthenium(ii)p-cymene derivative of quercetin was synthesized and functionally tested for cholesterol-lowering abilityviadirect 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) inhibition.

Zebrafish dives into food research: effectiveness assessment of bioactive compounds

Zebrafish ease of use and characteristics reveal it to be an interesting and underused model in food and nutrition research.

Long-term hyperphagia and caloric restriction caused by low- or high-density husbandry have differential effects on zebrafish postembryonic development, somatic growth, fat accumulation and reproduction

In recent years, the zebrafish (Danio rerio) has emerged as an alternative vertebrate model for energy homeostasis and metabolic diseases, including obesity and anorexia. It has been shown that diet-induced obesity (DIO) in zebrafish shares multiple pathophysiological features with obesity in mammals. However, a systematic and comprehensive analysis of the different pathways of energy expenditure in obese and starved fish had been missing thus far. Here, we carry out long-term ad libitum feeding (hyperphagia) and caloric restriction studies induced by low- or high-density husbandry, respectively, to investigate the impact of caloric intake on the timing of scale formation, a crucial step of postembryonic development and metamorphosis, and on somatic growth, body weight, fat storage and female reproduction. We show that all of them are positively affected by increased caloric intake, that middle-aged fish develop severe DIO, and that the body mass index (BMI) displays a strict linear correlation with whole-body triglyceride levels in adult zebrafish. Interestingly, juvenile fish are largely resistant to DIO, while BMI and triglyceride values drop in aged fish, pointing to aging-associated anorexic effects. Histological analyses further indicate that increased fat storage in white adipose tissue involves both hyperplasia and hypertrophy of adipocytes. Furthermore, in ovaries, caloric intake primarily affects the rate of oocyte growth, rather than total oocyte numbers. Finally, comparing the different pathways of energy expenditure with each other, we demonstrate that they are differentially affected by caloric restriction / high-density husbandry. In juvenile fish, scale formation is prioritized over somatic growth, while in sexually mature adults, female reproduction is prioritized over somatic growth, and somatic growth over fat storage. Our data will serve as a template for future functional studies to dissect the neuroendocrine regulators of energy homeostasis mediating differential energy allocation.

Effects of various fibre-rich extracts on cholesterol binding capacity during in vitro digestion of pork patties

Intake of foods containing high levels of cholesterol harms human health, and an increase in the intake of dietary fibre (DF) may mitigate these negative effects.

Partial cloning, tissue distribution and effects of epigallocatechin gallate on hepatic 3-hydroxy-3-methylglutaryl-CoA reductase mRNA transcripts in goldfish (Carassius auratus)

Epigallocatechin gallate (EGCG), the major active component of the green tea, has recently been found to inhibit 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoAR) activity in vitro and to modulate lipogenesis in vivo. In this study we have evaluated the effects of short-term in vivo exposure to EGCG (6 μg g(-1) BW or 9 μg g(-1) BW) on hepatic HMGCoAR gene expression of goldfish (Carassius auratus). We initially characterized a partial sequence of goldfish HMGCoAR suggesting that the obtained fragment shares high similarity (>92%) with other fish HMGCoAR sequences. Further, the HMGCoAR transcript was detected in all goldfish tissues (except muscle) but primarily in liver, brain and gonads; on the contrary, low expression levels were found in intestine, heart, gill, and kidney. Both EGCG doses significantly decreased hepatic HMGCoAR mRNA levels 180 min post-injection. HMGCoAR was also significantly down-regulated at 90 min after injection in fish treated with the highest dose of EGCG. Our results demonstrate that hepatic HMGCoAR gene expression is acutely responsive to short-term EGCG exposure in goldfish. This finding suggests a potential role of EGCG in transcriptional regulation of the rate-limiting enzyme in cholesterol synthesis.