Lutein prevents high fat diet-induced atherosclerosis in ApoE-deficient mice by inhibiting NADPH oxidase and increasing PPAR expression

Targeted Delivery and ROS-Responsive Release of Lutein Nanoassemblies Inhibit Myocardial Ischemia-Reperfusion Injury by Improving Mitochondrial Function

Purpose

Myocardial ischemia-reperfusion injury (MI/RI) is associated with increased oxidative damage and mitochondrial dysfunction, resulting in an elevated risk of mortality. MI/RI may be alleviated by protecting cardiomyocytes from oxidative stress. Lutein, which belongs to a class of carotenoids, has proven to be effective in cardiovascular disease treatment due to its remarkable antioxidant properties, but its application is limited due to its poor stability and low bioavailability in vivo.

Methods

In this study, a delivery system was developed based on distearoyl phosphatidyl ethanolamine (DSPE)-thiol-ketone (TK)-PEG2K (polyethylene glycol 2000) (abbreviated as DTP) and PCM-SH (CWLSEAGPVVTVRALRGTGSW) to deliver lutein (abbreviated as lutein@DTPP) to damaged myocardium. First, lutein, lutein@DTP, or lutein@DTPP were injected through the tail vein once a day for 3 days and then MI/RI model rats were established by exposing rats to ischemia for 45 min and reperfusion for 6 h. We employed a range of experimental techniques including qRT-PCR, Western blotting, transmission electron microscopy, immunohistochemistry, immunofluorescence, flow cytometry, immunoprecipitation, molecular docking, and molecular dynamics simulations.

Results

Lutein@DTPP exhibited good myocardial targeting and ROS-responsive release. Our data suggested that lutein@DTPP effectively suppresses ferroptosis in cardiomyocytes. Mechanistically, we observed an upregulation of mouse double minute-2 (MDM2) in the hearts of MI/RI models and cardiomyocytes exposed to hypoxia/reoxygenation (H/R) conditions. In addition, NADH-ubiquinone oxidoreductase 75 kDa Fe-S protein 1 (NDUFS1) translocation from the cytosol to the mitochondria was inhibited by MDM2 upregulation. Notably, no significant variation in the total NDUFS1 expression was observed in H/R-exposed cardiomyocytes following treatment with siMDM2. Further study indicated that lutein facilitates the translocation of NDUFS1 from the cytosol to mitochondria by directly binding and sequestering MDM2, thereby improving mitochondrial function and inhibiting ferroptosis.

Conclusion

Lutein@DTPP promoted the mitochondrial translocation of NDUFS1 to restore mitochondrial function and inhibited the ferroptosis of cardiomyocytes by directly binding and sequestering MDM2.

Molecular mechanisms underlying hepatoprotective activity of lutein in the context of intestinal failure-associated liver disease

Intestinal failure-associated liver disease (IFALD) is a spectrum of liver diseases occurring in patients not exposed to liver-damaging factors other than those linked to intestinal dysfunction. The pathogenesis of this disease is multifactorial. It is estimated that up to 90 % of people taking long-term parenteral nutrition may develop IFALD, with particular risk for premature neonates and infants due to their immature antioxidant protection and bile acid metabolism. The lack of effective prevention and treatment methods for IFALD encourages scientists to search for new therapeutic solutions. The use of lutein as a substance with antioxidant and anti-inflammatory effects seems to be of great potential in such indication, especially since patients on parenteral nutrition are at risk of deficits in various plant-based nutrients, including lutein. In this review, we explain the pathogenesis of IFALD and summarize knowledge of the hepatoprotective properties of lutein, underscoring its potential as a treatment option. The hepatoprotective effects of lutein and their proposed mechanisms of action are supported by studies on cells and animals exposed to various liver-damaging factors, such as lipopolysaccharide, high-fat diet, alcohol, and more. Finally, we provide perspectives on the future application of lutein in therapy.

Plant Antioxidants: Therapeutic Potential in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are a global health problem. The mortality associated with them is one of the highest. Essentially, CVDs occur when the heart or blood vessels are damaged. Oxidative stress is an imbalance between the production of reactive oxygen species (free radicals) and antioxidant defenses. Increased production of reactive oxygen species can cause cardiac and vascular injuries, leading to CVDs. Antioxidant therapy has been shown to have beneficial effects on CVDs. Plants are a rich source of bioactive antioxidants on our planet. Several classes of these compounds have been identified. Among them, carotenoids and phenolic compounds are the most potent antioxidants. This review summarizes the role of some carotenoids (a/β-carotene, lycopene and lutein), polyphenols such as phenolic acids (caffeic, p-coumaric, ferulic and chlorogenic acids), flavonoids (quercetin, kaempferol and epigallocatechin gallate), and hydroxytyrosol in mitigating CVDs by studying their biological antioxidant mechanisms. Through detailed analysis, we aim to provide a deeper understanding of how these natural compounds can be integrated into cardiovascular health strategies to help reduce the overall burden of CVD.

Agro-Industrial By-Products of Plant Origin: Therapeutic Uses as well as Antimicrobial and Antioxidant Activity

The importance of bioactive compounds in agro-industrial by-products of plant origin lies in their direct impacts on human health. These compounds have been shown to possess antioxidant, anti-inflammatory, and antimicrobial properties, contributing to disease prevention and strengthening the immune system. In particular, the antimicrobial action of these compounds emerges as an important tool in food preservation, providing natural alternatives to synthetic preservatives and contributing to combating antimicrobial resistance. Using agro-industrial by-products of plant origin not only addresses the need to reduce waste and promote sustainability but also inaugurates a new era in the formulation of functional foods. From fruit peels to pulps and seeds, these by-products are emerging as essential ingredients in the creation of products that can promote health. Continued research in this area will unveil new applications and properties of these by-products and open doors to a food paradigm in which health and sustainability converge, paving the way to a healthier and more equitable future. The present review presents an overview of our knowledge of agro-industrial by-products and some of their more relevant health-promoting bioactivities.

A Narrative Review: The Effect and Importance of Carotenoids on Aging and Aging-Related Diseases

Aging is generally defined as a time-dependent functional decline that affects most living organisms. The positive increase in life expectancy has brought along aging-related diseases. Oxidative stress caused by the imbalance between pro-oxidants and antioxidants can be given as one of the causes of aging. At the same time, the increase in oxidative stress and reactive oxygen species (ROS) is main reason for the increase in aging-related diseases such as cardiovascular, neurodegenerative, liver, skin, and eye diseases and diabetes. Carotenoids, a natural compound, can be used to change the course of aging and aging-related diseases, thanks to their highly effective oxygen-quenching and ROS-scavenging properties. Therefore, in this narrative review, conducted using the PubMed, ScienceDirect, and Google Scholar databases and complying with the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines, the effects of carotenoids on aging and aging-related diseases were analyzed. Carotenoids are fat-soluble, highly unsaturated pigments that occur naturally in plants, fungi, algae, and photosynthetic bacteria. A large number of works have been conducted on carotenoids in relation to aging and aging-related diseases. Animal and human studies have found that carotenoids can significantly reduce obesity and fatty liver, lower blood sugar, and improve liver fibrosis in cirrhosis, as well as reduce the risk of cardiovascular disease and erythema formation, while also lowering glycated hemoglobin and fasting plasma glucose levels. Carotenoid supplementation may be effective in preventing and delaying aging and aging-related diseases, preventing and treating eye fatigue and dry eye disease, and improving macular function. These pigments can be used to stop, delay, or treat aging-related diseases due to their powerful antioxidant, restorative, anti-proliferative, anti-inflammatory, and anti-aging properties. As an increasingly aging population emerges globally, this review could provide an important prospective contribution to public health.

The anti-inflammatory effect of lutein in broilers is mediated by regulating TLR4/MyD88 signaling pathway

The anti-inflammatory role of lutein has been widely recognized, however, the underlying mechanism is still not fully elucidated. Hence, the effects of lutein on the intestinal health and growth performance of broilers and the action of mechanism were investigated. 288 male yellow-feathered broilers (1-day old) were randomly allocated to 3 treatment groups with 8 replicates of 12 birds each, and the control group was fed a broken rice-soybean basal diet, while the test groups were fed a basal diet added with 20 mg/kg and 40 mg/kg of lutein (LU20, LU40), respectively. The feeding trial lasted for 21 d. The results showed that 40 mg/kg lutein supplementation tended to increase ADFI (P = 0.10) and ADG (P = 0.08) of broilers. Moreover, the addition of lutein caused a decreasing trend of gene expression and concentration of proinflammatory cytokines IL-1β (P = 0.08, P = 0.10, respectively) and IL-6 (P = 0.06, P = 0.06, respectively) and also tended to decrease the gene expression of TLR4 (P = 0.09) and MyD88 (P = 0.07) while increasing gene expression and concentration of anti-inflammatory cytokines IL-4 and IL-10 (P < 0.05) in the jejunum mucosa of broilers. Additionally, lutein supplementation increased the jejunal villi height of broilers (P < 0.05) and reduced villi damage. The experiment in vitro showed that lutein treatment reduced the gene expression of IL-1β, IL-6, and IFN-γ in chicken intestinal epithelial cells (P < 0.05). However, this effect was diminished after knock-down of TLR4 or MyD88 genes using RNAi technology. In conclusion, lutein can inhibit the expression and secretion of proinflammatory cytokines in the jejunum mucosa and promote intestinal development of broilers, and the anti-inflammatory effect may be achieved by regulating TLR4/MyD88 signaling pathway.

The effect of lutein and Zeaxanthine on dyslipidemia: A meta-analysis study

AIMS

The relationship between circulating Lutein and zeaxanthin (L/Z) concentrations, and plasma lipoproteins has been indicated by observational studies. However, the beneficial impact of L/Z administration on dyslipidemia are unclear. This meta-analysis aimed to investigate the effect of oral intake of L/Z on circulating total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), as well as high-density lipoprotein-cholesterol (HDL-C) levels.

METHODS

We electronically assessed all eligible interventional studies through different electronic databases, including PubMed, Scopus, ISI -Web of Science, and Cochrane library until Jun 2021. After identifying the quality of each included randomized controlled trials, they were evaluated by assessing the risk-difference between treatment and control groups by pooling available data on net change of serum LDL-C, HDL-C, and Cholesterol.

RESULTS

L/Z supplementation has null effect on circulating levels of TC (WMD: -3.82 95% CI: -13.83, 6.18; I-square: 85.2%), and LDL-C (WMD: -4.54; 95% CI: -11.5, 2.48; I-square: 83.9%). In contrast, L/Z treatment could significantly increase HDL-C levels in older adults (WMD: 4.06; 95% CI: 0.64, 7.48; I-square: 50.7%).

CONCLUSION

L/Z administration could be an effective treatment for improving circulating HDL-C concentration in elderly adults.

Effects of Riceberry Rice Bran Oil Supplementation on Oxidative Stress and Cardiovascular Risk Biomarkers in Older Adults with Prehypertension

We investigated the changes in the oxidative stress and cardiovascular disease risk biomarkers, including the activity of the cardiac autonomic nervous system, in older adults with prehypertension following Riceberry rice bran oil supplementation. A total of 35 women aged 60 to 76 years with prehypertension were randomly allocated to two groups, one of which was supplemented with rice bran oil (n=18) and the other with Riceberry rice bran oil (n=17) at 1,000 mg daily for 8 weeks. Prior to and after the supplementation, oxidative stress and cardiovascular risk biomarkers (primary outcomes), heart rate variability, and blood pressure (secondary outcomes) were investigated. Results showed that plasma malondialdehyde, blood glutathione disulfide, and tumor necrosis factor-alpha levels were significantly decreased, and the ratio of reduced glutathione to glutathione disulfide significantly increased in both groups after supplementation (all P<0.05). No significant differences were observed between groups. Heart rate variability and blood pressure did not statistically significantly change subsequent to supplementation in either group and did not differ between groups. In conclusion, Riceberry rice bran oil supplementation for 8 weeks alleviates oxidative stress and inflammation in older adults with prehypertension to a similar extent as rice bran oil supplementation.

The effect of Chlorella vulgaris on obesity related metabolic disorders: a systematic review of randomized controlled trials

OBJECTIVES

Chlorella vulgaris (CV) as a unicellular algae is a dietary supplement with beneficial nutritious content, used for decades in some countries. Positive effects for CV supplementation on metabolic parameters has been established in animal and human studies. However there is a gap for this results summary for a definite conclusion announce. This systematic review aimed to summarize the effects of CV on body weight, lipid profile, and blood glucose.

CONTENT

PRISMA guidelines were charted in this review. Subject search was performed in MEDLINE, ProQuest, PubMed, ISI web of sciences, Google scholar, Cochrane and Scopus databases for randomized clinical trials published in English languages, until December 2020, which assessed the effects of CV on metabolic syndrome related symptoms in clinical trials.

SUMMARY

Out of 4,821 records screened, after duplicate and irrelevant exclusion by title and abstract, 20 articles remained for full text screening. Finally a total of 12 articles met the study inclusion criteria and were assessed for study method and results.

OUTLOOK

The findings showed controversies in anthropometric, glycemic and lipid profile effects. CV may have beneficial effects on obesity-related metabolic disorders; however, collected studies lacked statistical power to reach a definite conclusion. More well-designed studies are required.

Bioinformatics analysis to screen for genes related to myocardial infarction

Myocardial infarction (MI) is an acute and persistent myocardial ischemia caused by coronary artery disease. This study screened potential genes related to MI. Three gene expression datasets related to MI were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened using the MetaDE package. Afterward, the modules and genes closely related to MI were screened and a gene co-expression network was constructed. A support vector machine (SVM) classification model was then constructed based on the GSE61145 dataset using the e1071 package in R. A total of 98 DEGs were identified in the MI samples. Next, three modules associated with MI were screened and an SVM classification model involving seven genes was constructed. Among them, BCL6, CEACAM8, and CUGBP2 showed co-interactions in the gene co-expression network. Therefore, ACOX1, BCL6, CEACAM8, and CUGBP2, in addition to GPX7, might be feature genes related to MI.

Cardioprotective effects of phytopigments via multiple signaling pathways

BACKGROUND

Cardiovascular diseases (CVDs) are among the deadliest non-communicable diseases, and millions of dollars are spent every year to combat CVDs. Unfortunately, the multifactorial etiology of CVDs complicates the development of efficient therapeutics. Interestingly, phytopigments show significant pleiotropic cardioprotective effects both in vitro and in vivo.

PURPOSE

This review gives an overview of the cardioprotective effects of phytopigments based on in vitro and in vivo studies as well as clinical trials.

METHODS

A literature-based survey was performed to collect the available data on cardioprotective activities of phytopigments via electronic search engines such as PubMed, Google Scholar, and Scopus.

RESULTS

Different classes of phytopigments such as carotenoids, xanthophylls, flavonoids, anthocyanins, anthraquinones alleviate major CVDs (e.g., cardiac hypertrophy, atherosclerosis, hypertension, cardiotoxicities) via acting on signaling pathways related to AMPK, NF-κB, NRF2, PPARs, AKT, TLRs, MAPK, JAK/STAT, NLRP3, TNF-α, and RA.

CONCLUSION

Phytopigments represent promising candidates to develop novel and effective CVD therapeutics. More randomized, placebo-controlled clinical studies are recommended to establish the clinical efficacy of phytopigments.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Acute inflammation is a key component of the immune system's response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

Matcha and Its Components Control Angiogenic Potential

The brain needs the appropriate capillary networks to maintain normal brain function. Since previous studies showed age-related decrease in the cortical capillaries, it is suggested that protection against capillary aging is critical for maintaining brain function. Epidemiological studies have indicated that brain functions were protected from age-related decline by the long-term consumption of matcha. However, whether matcha has protective effects on capillary aging has not been studied yet. In this study, we utilized Flt1-DsR mice that expressed a red fluorescent protein in vascular endothelial cells to visualize cortical capillaries clearly. We found that cortical capillary density decreased in aging Flt1-DsR mice. Our results of the aortic ring assay and tube formation assay revealed that matcha and its components vitamin K₁ and lutein, which are abundant in matcha powder, enhanced the angiogenic potential. Moreover, we evaluated the effect of long-term ingestion of matcha on mouse cortical capillary aging by using imaging experiments. The capillary density of the Flt1-DsR mice, which were fed matcha-containing food, indicated the protective effects of matcha ingestion on capillary aging in a limited cortical layer. These results suggest that biological regulation of matcha and its components affect the angiogenic potential, which is related to the prevention of capillary aging.

Genetic factors involved in modulating lutein bioavailability

Lutein exhibits effective antioxidant activity conferring protective action against oxidative stress in age-related macular degeneration and cognitive decline. The inability to synthesize these compounds by the human body and the necessity to combat day-to-day oxidative stress prioritizes daily consumption of lutein. However, the bioavailability of the orally consumed lutein largely depends on its gastrointestinal absorption and subsequent metabolism which is in turn governed by various intrinsic and extrinsic factors. One of the most important yet least studied factors is the genetic make-up of an individual. The proteins that partake in the absorption, transportation, metabolism and excretion of lutein are encoded by the genes that experience inter-individual variability. Reports suggest that the unanimous effect of phenotypes resulting from such inter-individual variability in the genes of interest causes modulation of lutein bioavailability which is discussed in detail in this review article. However, despite the available reports, a community-based approach to a larger population is required to obtain a stronger understanding of the relationship between inter-individual variability among these genes and lutein bioavailability. Such an understanding of nutrigenetics could not only pave a way to decipher mechanisms that modulate lutein bioavailability but also help in setting the dosage requirements of each patient.

Lutein supplementation combined with a low-calorie diet in middle-aged obese individuals: effects on anthropometric indices, body composition and metabolic parameters

Lutein is considered as a major biologically active carotenoid, with potential benefits for obesity and cardiometabolic health. This double-blind, randomised controlled trial aimed to assess whether the consumption of lutein along with a low-calorie diet (LCD) can influence anthropometric indices, body composition and metabolic parameters in obese middle-aged individuals. After a 2-week run-in period with an LCD, forty-eight participants aged 45–65 years were randomly assigned to consume 20 mg/d lutein or placebo along with the LCD for 10 weeks. Dietary intake, anthropometric indices, body composition, lipid profile, glucose homoeostasis parameters, NEFA and appetite sensations were assessed at the beginning and end of the study. After 10 weeks, body weight and waist circumference significantly decreased in both groups, although between-group differences were not significant. There was more of a decrease in the percentage of body fat in the lutein group v. the placebo group. Moreover, the placebo group experienced a significant reduction in fat-free mass (FFM), whereas the lutein group preserved FFM during calorie restriction, although the between-group difference did not reach statistical significance. Visceral fat and serum levels of total cholesterol (TC) and LDL-cholesterol were significantly decreased only in the lutein group, with a statistically significant difference between the two arms only for TC. No significant changes were observed in the TAG, HDL-cholesterol, glucose homoeostasis parameters, NEFA and appetite sensations. Lutein supplementation in combination with an LCD could improve body composition and lipid profile in obese middle-aged individuals.

Omega-3 Phospholipids from Krill Oil Enhance Intestinal Fatty Acid Oxidation More Effectively than Omega-3 Triacylglycerols in High-Fat Diet-Fed Obese Mice

Antisteatotic effects of omega-3 fatty acids (Omega-3) in obese rodents seem to vary depending on the lipid form of their administration. Whether these effects could reflect changes in intestinal metabolism is unknown. Here, we compare Omega-3-containing phospholipids (krill oil; ω3PL-H) and triacylglycerols (ω3TG) in terms of their effects on morphology, gene expression and fatty acid (FA) oxidation in the small intestine. Male C57BL/6N mice were fed for 8 weeks with a high-fat diet (HFD) alone or supplemented with 30 mg/g diet of ω3TG or ω3PL-H. Omega-3 index, reflecting the bioavailability of Omega-3, reached 12.5% and 7.5% in the ω3PL-H and ω3TG groups, respectively. Compared to HFD mice, ω3PL-H but not ω3TG animals had lower body weight gain (−40%), mesenteric adipose tissue (−43%), and hepatic lipid content (−64%). The highest number and expression level of regulated intestinal genes was observed in ω3PL-H mice. The expression of FA ω-oxidation genes was enhanced in both Omega-3-supplemented groups, but gene expression within the FA β-oxidation pathway and functional palmitate oxidation in the proximal ileum was significantly increased only in ω3PL-H mice. In conclusion, enhanced intestinal FA oxidation could contribute to the strong antisteatotic effects of Omega-3 when administered as phospholipids to dietary obese mice.

Isolation and Characterization of Novel Chlorella Vulgaris Mutants With Low Chlorophyll and Improved Protein Contents for Food Applications

Microalgae are widely used as food supplements due to their high protein content, essential fatty acids and amino acids as well as carotenoids. The addition of microalgal biomass to food products (e.g., baked confectioneries) is a common strategy to attract novel consumers. However, organoleptic factors such as color, taste and smell can be decisive for the acceptability of foods supplemented with microalgae. The aim of this work was to develop chlorophyll-deficient mutants of Chlorella vulgaris by chemically induced random mutagenesis to obtain biomass with different pigmentations for nutritional applications. Using this strategy, two C. vulgaris mutants with yellow (MT01) and white (MT02) color were successfully isolated, scaled up and characterized. The changes in color of MT01 and MT02 mutant strains were due to an 80 and 99% decrease in their chlorophyll contents, respectively, as compared to the original wild type (WT) strain. Under heterotrophic growth, MT01 showed a growth performance similar to that of the WT, reaching a concentration of 5.84 and 6.06 g L⁻¹, respectively, whereas MT02 displayed slightly lower growth (4.59 g L⁻¹). When grown under a light intensity of 100 μmol m⁻² s⁻¹, the pigment content in MT01 increased without compromising growth, while MT02 was not able to grow under this light intensity, a strong indication that it became light-sensitive. The yellow color of MT01 in the dark was mainly due to the presence of the xanthophyll lutein. On the other hand, phytoene was the only carotenoid detected in MT02, which is known to be colorless. Concomitantly, MT02 contained the highest protein content, reaching 48.7% of DW, a 60% increase as compared to the WT. MT01 exhibited a 30% increase when compared to that of the WT, reaching a protein content of 39.5% of DW. Taken together, the results strongly suggest that the partial abrogation of pigment biosynthesis is a factor that might promote higher protein contents in this species. Moreover, because of their higher protein and lower chlorophyll contents, the MT01 and MT02 strains are likely candidates to be feedstocks for the development of novel, innovative food supplements and foods.

Nutraceutical approach to enhance lutein bioavailability via nanodelivery systems

Lutein, a potent dietary carotenoid, has considerable biological activity and confers protection against age-related macular degeneration. Its bioavailability following consumption, however, depends on its rate of degradation. Nanodelivery systems with improved efficacy and stability are currently being developed to increase the bioavailability of lutein. This review examines nutraceutical approaches used in the development of such nanodelivery systems. It describes the methods of lutein preparation, the characteristics of various delivery systems, and the lutein delivery profile. In order to enhance lutein loading, provide electrostatic stabilization, and achieve the controlled release of lutein, adjuvants such as dextran moieties, whey proteins, medium-chain triglycerides, and chitosan polymers can be used to effectively reduce the particle size (&lt; 70 nm) and improve encapsulation efficiency (to 99.5%). The improved bioavailability of lutein via nanocrystals incorporated into rapidly dissolving films for oral consumption is a new area of exploratory research. This review aims to provide clarity about current research aimed at enhancing the bioavailability of lutein through the development of nanodelivery systems.

Effects of lutein supplementation on inflammatory biomarkers and metabolic risk factors in adults with central obesity: study protocol for a randomised controlled study

Background

The prevalence of central obesity is constantly increasing, and visceral fat is associated with increased production of inflammatory factors and metabolic risk factors. Lutein might retard the development of metabolic disease through its antioxidant and anti-inflammatory properties. Furthermore, epidemiological studies have associated higher dietary intake and serum levels of lutein with decreased adiposity. However, few randomised controlled trials have shown the effects of lutein supplementation on inflammatory biomarkers and metabolic risk factors, especially in adults with central obesity.

Methods

This study will be conducted as a double-blind, parallel placebo-controlled clinical trial in which 120 people who have central obesity, are 18 to 60 years old and are willing to provide informed consent will be randomly assigned to the intervention or placebo group in a 1:1 ratio according to sex, age and waist circumference. The intervention group will receive 10 mg daily lutein supplementation for 12 weeks to explore the effect of lutein supplementation on serum lutein, glycaemic and lipid profiles, inflammatory factors and body composition. Two populations (intention-to-treat population and per-protocol population) will be used in the data analyses.

Discussion

Our findings from this trial will contribute to the knowledge of the association between lutein supplementation and inflammatory biomarkers and metabolic risk factors in people with central obesity and will offer a possibility for the prevention of inflammatory diseases.

Trial registration

Chinese Clinical Trial Registry: ChiCTR1800018098. Registered on 30 August 2018.

Mechanistic insights into the effect of lutein on atherosclerosis, vascular dysfunction, and related risk factors: A systematic review of in vivo, ex vivo and in vitro studies

Lutein is an essential carotenoid commonly consumed in the diet; however, its dietary intake does not usually reach the minimum recommended intake to decrease the incidence of chronic diseases. Experimental and epidemiological evidence suggests an anti-atherosclerotic effect for lutein-rich foods or lutein supplementation. This systematic review aimed to assess the mechanistic pathways of lutein in the prevention of atherosclerosis. Electronic databases, including PubMed, SCOPUS, ProQuest, Embase, and Google Scholar were searched to May 2019. Original studies published in English-language journals that investigated the effects of lutein on atherosclerosis and related risk factors, including lipid profile, hemodynamic, glycemic and inflammatory measurements, and endothelial function indices, were considered. Two reviewers independently extracted data on study characteristics, methods and outcomes. The review protocol has been registered at PROSPERO database of Systematic Reviews (registration number: CRD42019121381). A total of 5818 articles were found in the first phase of the search; from these, 19 met the inclusion criteria: 3 in vitro, 1 ex vivo, 11 animal, and 4 human studies. Nine of ten studies showed positive effects of lutein on endothelial function by reducing blood pressure, arterial thickness, monocyte migration, and vascular smooth muscle cell migration. Twelve studies examined the anti-inflammatory properties of lutein and found a significant decrease in proinflammatory cytokines. Although few studies investigated the anti-hyperlipidemic effects of lutein, three animal studies and one clinical trial found a beneficial effect of lutein on lipid profile. Evidence supports positive effects of lutein on atherosclerosis development and some common risk factors of atherosclerosis, including inflammation and endothelial dysfunction. Further studies focused on the effects of lutein on hyperglycemia, lipid profile, blood pressure and coagulation are required.

Factors influencing the cardiometabolic response to (poly)phenols and phytosterols: a review of the COST Action POSITIVe activities

Purpose

Evidence exists regarding the beneficial effects of diets rich in plant-based foods regarding the prevention of cardiometabolic diseases. These plant-based foods are an exclusive and abundant source of a variety of biologically active phytochemicals, including polyphenols, carotenoids, glucosinolates and phytosterols, with known health-promoting effects through a wide range of biological activities, such as improvements in endothelial function, platelet function, blood pressure, blood lipid profile and insulin sensitivity. We know that an individual’s physical/genetic makeup may influence their response to a dietary intervention, and thereby may influence the benefit/risk associated with consumption of a particular dietary constituent. This inter-individual variation in responsiveness has also been described for dietary plant bioactives but has not been explored in depth. To address this issue, the European scientific experts involved in the COST Action POSITIVe systematically analyzed data from published studies to assess the inter-individual variation in selected clinical biomarkers associated with cardiometabolic risk, in response to the consumption of plant-based bioactives (poly)phenols and phytosterols. The present review summarizes the main findings resulting from the meta-analyses already completed.

Results

Meta-analyses of randomized controlled trials conducted within POSITIVe suggest that age, sex, ethnicity, pathophysiological status and medication may be responsible for the heterogeneity in the biological responsiveness to (poly)phenol and phytosterol consumption and could lead to inconclusive results in some clinical trials aiming to demonstrate the health effects of specific dietary bioactive compounds. However, the contribution of these factors is not yet demonstrated consistently across all polyphenolic groups and cardiometabolic outcomes, partly due to the heterogeneity in trial designs, low granularity of data reporting, variety of food vectors and target populations, suggesting the need to implement more stringent reporting practices in the future studies. Studies investigating the effects of genetic background or gut microbiome on variability were limited and should be considered in future studies.

Conclusion

Understanding why some bioactive plant compounds work effectively in some individuals but not, or less, in others is crucial for a full consideration of these compounds in future strategies of personalized nutrition for a better prevention of cardiometabolic disease. However, there is also still a need for the development of a substantial evidence-base to develop health strategies, food products or lifestyle solutions that embrace this variability.

A balanced diet, rich in plant-based foods is known for the prevention of obesity, diabetes, and cardiovascular disease risk.

(Poly)phenols and phytosterols displayed a range of biological effects of relevance to contribute to the cardiometabolic health benefits of plant foods

However, inter-individual variability in response to plant food bioactive consumption exists, and there is a need to understand the causes of this variation.

Analysis of published RCTs examining impact of consumption of (poly)phenols and phytosterols on cardiometabolic risk factors demonstrated that a number of factors including age, sex, adiposity and health status could contribute to the effect demonstrated within these studies.

Genome and microbiome studies will help identify what may be causing this variation.

More studies, specifically designed to investigate individual variation are needed to fully understand the factors responsible for and the impact of this variation

Once fully understood, such variation should be used in directing personalised nutrition advice.

Efficacy of Terpenoid in Attenuating Aortic Atherosclerosis in Apolipoprotein-E Deficient Mice: A Meta-Analysis of Animal Studies

Background

The apolipoprotein E knockout (ApoE -/-) mouse model is well established for the study of terpenoids in the prevention of atherosclerosis. Studies investigating the clinical benefit of terpenoids in humans are scarce. This systematic review and meta-analysis evaluated the effects of terpenoid administration on atherosclerotic lesion area in ApoE -/- mice.

Methods

A comprehensive literature search using PubMed, Embase, and the Cochrane Library databases was performed to identify studies that assessed the effects of terpenoids on atherosclerosis in ApoE -/- mice. The primary outcome was atherosclerotic lesion area, and study quality was estimated using SYRCLE's risk of bias tool.

Results

The meta-analysis included 25 studies. Overall, terpenoids significantly reduced atherosclerotic lesion area when compared to vehicle control (P<0.00001; SMD: -0.55; 95% CI: -0.72, -0.39). In terpenoid type and dose subgroup analyses, sesquiterpenoid (P=0.002; SMD -0.93; 95% CI: -1.52, -0.34), diterpenoid (P=0.01; SMD: -0.30; 95% CI: -0.54, -0.06), triterpenoid (P<0.00001; SMD: -0.66; 95% CI: -0.94, -0.39), tetraterpenoid (P<0.0001; SMD: -1.81; 95% CI: -2.70, -0.91), low dose (P=0.0001; SMD: -0.51; 95% CI: -0.76, -0.25), medium dose (P<0.0001; SMD: -0.48; 95% CI: -0.72, -0.24), and high dose (P=0.002; SMD: -1.07; 95% CI: -1.74, -0.40) significantly decreased atherosclerotic lesion area when compared to vehicle control. PROSPERO register number is CRD42019121176.

Conclusion

Sesquiterpenoid, diterpenoid, triterpenoid, and tetraterpenoid have potential as antiatherosclerotic agents with a wide range of doses. This systematic review provides a reference for research programs aimed at the development of terpenoid-based clinical drugs.

Ameliorative Effect of Spinach on Non-Alcoholic Fatty Liver Disease Induced in Rats by a High-Fat Diet

The purpose of this work was to evaluate the effect of dietary carotenoids from spinach on the inflammation and oxidative stress biomarkers, liver lipid profile, and liver transcriptomic and metabolomics profiles in Sprague–Dawley rats with steatosis induced by a high-fat diet. Two concentrations of spinach powder (2.5 and 5%) were used in two types of diet: high-fat (H) and standard (N). Although rats fed diet H showed an accumulation of fat in hepatocytes, they did not show differences in the values of adiponectin, tumor necrosis factor alpha (TNF-α), and oxygen radical absorption (ORAC) in plasma or of isoprostanes in urine compared with animals fed diet N. The consumption of spinach and the accumulation of α and β carotenes and lutein in the liver was inversely correlated with serum total cholesterol and glucose and the content of hepatic cholesterol, increasing monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and reducing cholesterol in the livers of rats fed diet H and spinach. In addition, changes in the expression of genes related to the fatty liver condition occurred, and the expression of genes involved in the metabolism of fatty acids and cholesterol increased, mainly through the overexpression of peroxisome proliferator activated receptors (PPARs). Related to liver metabolites, animals fed with diet H showed hypoaminoacidemia, mainly for the glucogenic aminoacids. Although no changes were observed in inflammation and oxidative stress biomarkers, the consumption of spinach modulated the lipid metabolism in liver, which must be taken into consideration during the dietary treatment of steatosis.

The Effect of Lutein on Eye and Extra-Eye Health

Lutein is a carotenoid with reported anti-inflammatory properties. A large body of evidence shows that lutein has several beneficial effects, especially on eye health. In particular, lutein is known to improve or even prevent age-related macular disease which is the leading cause of blindness and vision impairment. Furthermore, many studies have reported that lutein may also have positive effects in different clinical conditions, thus ameliorating cognitive function, decreasing the risk of cancer, and improving measures of cardiovascular health. At present, the available data have been obtained from both observational studies investigating lutein intake with food, and a few intervention trials assessing the efficacy of lutein supplementation. In general, sustained lutein consumption, either through diet or supplementation, may contribute to reducing the burden of several chronic diseases. However, there are also conflicting data concerning lutein efficacy in inducing favorable effects on human health and there are no univocal data concerning the most appropriate dosage for daily lutein supplementation. Therefore, based on the most recent findings, this review will focus on lutein properties, dietary sources, usual intake, efficacy in human health, and toxicity.

Exploring the Valuable Carotenoids for the Large-Scale Production by Marine Microorganisms

Carotenoids are among the most abundant natural pigments available in nature. These pigments have received considerable attention because of their biotechnological applications and, more importantly, due to their potential beneficial uses in human healthcare, food processing, pharmaceuticals and cosmetics. These bioactive compounds are in high demand throughout the world; Europe and the USA are the markets where the demand for carotenoids is the highest. The in vitro synthesis of carotenoids has sustained their large-scale production so far. However, the emerging modern standards for a healthy lifestyle and environment-friendly practices have given rise to a search for natural biocompounds as alternatives to synthetic ones. Therefore, nowadays, biomass (vegetables, fruits, yeast and microorganisms) is being used to obtain naturally-available carotenoids with high antioxidant capacity and strong color, on a large scale. This is an alternative to the in vitro synthesis of carotenoids, which is expensive and generates a large number of residues, and the compounds synthesized are sometimes not active biologically. In this context, marine biomass has recently emerged as a natural source for both common and uncommon valuable carotenoids. Besides, the cultivation of marine microorganisms, as well as the downstream processes, which are used to isolate the carotenoids from these microorganisms, offer several advantages over the other approaches that have been explored previously. This review summarizes the general properties of the most-abundant carotenoids produced by marine microorganisms, focusing on the genuine/rare carotenoids that exhibit interesting features useful for potential applications in biotechnology, pharmaceuticals, cosmetics and medicine.

Siphonaxanthin, a Carotenoid From Green Algae, Inhibits Lipogenesis in Hepatocytes via the Suppression of Liver X Receptor α Activity

Nonalcoholic fatty liver disease (NAFLD) has shown an increasing morbidity in recent years. Here, we demonstrated that siphonaxanthin (SPX), a rare marine carotenoid, exhibits a strong inhibitory effect on aggravated hepatic lipogenesis in vitro and would be a promising candidate in the prevention and alleviation of NAFLD in the future. In this study, we conducted a preliminary assessment of the effect of SPX on hepatic lipogenesis by using the HepG2 cell line, derived from human liver cancer, as a model of the liver. SPX significantly suppressed the excess accumulation of triacylglycerol induced by liver X receptor α (LXRα) agonist by downregulating a nuclear transcription factor named sterol regulatory element-binding protein-1c and a set of related genes. Moreover, fatty acid translocase (CD36) and fatty acid-binding protein-1, which regulates fatty acid uptake, also exhibited significant decrease in transcriptional levels. Furthermore, we found that SPX blocked LXRα activation and would be a promising candidate for antagonist of LXRα.

Dietary Flaxseed Oil Prevents Western-Type Diet-Induced Nonalcoholic Fatty Liver Disease in Apolipoprotein-E Knockout Mice

The prevalence of nonalcoholic fatty liver disease (NAFLD) has dramatically increased globally during recent decades. Intake of n-3 polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3), is believed to be beneficial to the development of NAFLD. However, little information is available with regard to the effect of flaxseed oil rich in α-linolenic acid (ALA, C18:3n-3), a plant-derived n-3 PUFA, in improving NAFLD. This study was to gain the effect of flaxseed oil on NAFLD and further investigate the underlying mechanisms. Apolipoprotein-E knockout (apoE-KO) mice were given a normal chow diet, a western-type high-fat and high-cholesterol diet (WTD), or a WTD diet containing 10% flaxseed oil (WTD + FO) for 12 weeks. Our data showed that consumption of flaxseed oil significantly improved WTD-induced NAFLD, as well as ameliorated impaired lipid homeostasis, attenuated oxidative stress, and inhibited inflammation. These data were associated with the modification effects on expression levels of genes involved in de novo fat synthesis (SREBP-1c, ACC), triacylglycerol catabolism (PPARα, CPT1A, and ACOX1), inflammation (NF-κB, IL-6, TNF-α, and MCP-1), and oxidative stress (ROS, MDA, GSH, and SOD).

Lutein exerts anti-inflammatory effects in patients with coronary artery disease

BACKGROUND AND AIMS

Many coronary artery disease (CAD) patients exhibit chronic low-grade inflammation. Carotenoids are anti-oxidants with potential anti-inflammatory properties. Here, we first assessed relationships between interleukin (IL)-6 and individual carotenoids in plasma from CAD patients. Based on the results, we proceeded to assess anti-inflammatory effects of one carotenoid, lutein, in peripheral blood mononuclear cells (PBMCs) from CAD patients.

METHODS

Lutein + zeaxanthin (isomers with lutein being dominant), β-cryptoxanthin, lycopene, α- and β-carotene and IL-6 were measured in plasma from 134 patients with stable angina (SA) and 59 patients with acute coronary syndrome. In 42 patients, plasma measurements were also performed 3 months after coronary intervention. PBMCs from SA patients were pre-treated with lutein (1, 5 and 25 μM) for 24 h followed by 24 h incubation ± lipopolysaccharide (LPS). Cell pellets were collected for IL-6, IL-1β and TNF mRNA and intracellular lutein. Cytokine secretion was measured in cell media.

RESULTS

Only lutein + zeaxanthin were inversely correlated with IL-6 in SA patients at baseline (r = -0.366, p < 0.001) and follow-up (r = -0.546, p < 0.001). Ex vivo, lutein was taken up by PBMCs from SA patients in a dose- and time-dependent manner. Pre-treatment with lutein dose-dependently lowered LPS-induced secretion of IL-6, IL-1β (p < 0.01) and TNF (p < 0.05), and also reduced IL-6, IL-1β and TNF mRNA expression (p < 0.05).

CONCLUSIONS

Clinical findings highlighted the inverse association between lutein and IL-6 in CAD patients. Anti-inflammatory effects of lutein in PBMCs from CAD patients were consolidated in ex vivo experiments. Taken together, these results show that lutein has the potential to play a role in resolution of chronic inflammation in CAD patients.

Klotho ameliorates oxidized low density lipoprotein (ox-LDL)-induced oxidative stress via regulating LOX-1 and PI3K/Akt/eNOS pathways

Background

Atherosclerosis is a common cardiovascular disease that causes myocardial infarction, heart failure, and stroke. Increased oxidized low density lipoprotein (ox-LDL) in the sub-endothelium is the characteristic origin of atherogenesis. Klotho, an anti-aging protein, has been reported to protect against atherosclerosis and ameliorate endothelial dysfunction in vivo. The aim of this study is to investigatethe anti-oxidative activity of Klothoin ox-LDL-treated human umbilical vein endothelial cells (HUVECs).

Methods

After pre-treatment with 200 pMKlotho for 1 h, HUVECs were stimulated with 50 μg/ml ox-LDL for 24 h. Reactive oxygen species (ROS) and superoxide dismutase (SOD) levels were analyzed in the cells. Nitric oxide (NO) concertation was measured in the medium supernatant. Related proteins or genes were detected with Western blot or real time PCR, respectively, in the cell lysates.

Results

Initially, oxidative damage in HUVECs was established by adding 50 μg/mL ox-LDL, which resulted in decreased cellular viability, SOD/Cu/Zn-SOD and endothelial NO synthase (eNOS) expression and NO production, as well as increased malondialdehyde (MDA) levels, ROS production, inducible NO synthase (iNOS), phosphatidyl inositol-3 kinase (PI3K), protein kinase B (Akt), gp91 phox, and lectin-like ox-LDL receptor (LOX-1) expression in HUVECs. Pre-incubation with recombinant Klotho (200 pM) significantly prevented all of these alterations. These results suggest that Klotho can attenuate ox-LDL-induced oxidative stress in HUVECs through upregulating oxidative scavengers (SOD and NO) viaactivating the PI3K/Akt/eNOS pathway and depressing LOX-1expression.

Conclusions

These results suggest that Klotho has a potential therapeutic effect on attenuating endothelial dysfunction and ameliorating atherosclerosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-017-0447-0) contains supplementary material, which is available to authorized users.

Anti-obesity effects of zeaxanthin on 3T3-L1 preadipocyte and high fat induced obese mice

Zeaxanthin inhibited lipogenesis in adipocytes and attenuated progression of obesity in mice by inducing AMPK activation and suppressing adipocyte-specific factors.

The Multiple Facets of Lutein: A Call for Further Investigation in the Perinatal Period

Lutein may have important antioxidant actions in free-radical-mediated diseases, in addition to its well-known antioxidant and cytoprotective effects on macula and photoreceptors. The peculiar perinatal susceptibility to oxidative stress indicates that prophylactic use of antioxidants as lutein could help to prevent or at least to reduce oxidative stress related diseases in newborns. Since lutein is not synthesized by humans, the intake primarily depends on diet or supplementation. Newborns receive lutein exclusively from breast milk. Lutein supplementation in term newborns has been reported to reduce oxidative stress and increase antioxidant capacities in the first days of life. Innovative frontiers concerning lutein supplementation are orientated toward cardiometabolic health improvement and cognitive benefits. The safety of lutein as an antioxidant agent has been confirmed in experimental and clinical studies, but its routine use is not recommended in perinatal period. This review summarizes what is known about the role of lutein as an antioxidant and anti-inflammatory agent in animal model and humans.

3′-Hydroxy-ε,ε-caroten-3-one inhibits the differentiation of 3T3-L1 cells to adipocytes

An oxidative metabolite of lutein, 3′-hydroxy-ε,ε-caroten-3-one, inhibited the differentiation of 3T3-L1 cells to adipocytes and the subsequent triacylglycerol production, but lutein did not. The α,β-unsaturated carbonyl structure of 3′-hydroxy-ε,ε-caroten-3-one was considered to participate in the inhibitory effect, suggesting that this lutein metabolite has the potential to prevent metabolic syndrome.