Effects of astaxanthin in obese mice fed a high-fat diet

A marine-derived antioxidant astaxanthin as a potential neuroprotective and neurotherapeutic agent: A review of its efficacy on neurodegenerative conditions

Astaxanthin is a potent lipid-soluble carotenoid produced by several different freshwater and marine microorganisms, including microalgae, bacteria, fungi, and yeast. The proven therapeutic effects of astaxanthin against different diseases have made this carotenoid popular in the nutraceutical market and among consumers. Recently, astaxanthin is also receiving attention for its effects in the co-adjuvant treatment or prevention of neurological pathologies. In this systematic review, studies evaluating the efficacy of astaxanthin against different neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, cerebrovascular diseases, and spinal cord injury are analyzed. Based on the current literature, astaxanthin shows potential biological activity in both in vitro and in vivo models. In addition, its preventive and therapeutic activities against the above-mentioned diseases have been emphasized in studies with different experimental designs. In contrast, none of the 59 studies reviewed reported any safety concerns or adverse health effects as a result of astaxanthin supplementation. The preventive or therapeutic role of astaxanthin may vary depending on the dosage and route of administration. Although there is a consensus in the literature regarding its effectiveness against the specified diseases, it is important to determine the safe intake levels of synthetic and natural forms and to determine the most effective forms for oral intake.

Astaxanthin Alleviates Autoimmune Hepatitis by Modulating CD8+ T Cells: Insights From Mass Cytometry and Single-Cell RNA Sequencing Analyses

Astaxanthin (ASX) is an oxygen-containing non-vitamin A carotenoid pigment. However, the role of ASX in autoimmune hepatitis (AIH) remains unclear. In this study, a mouse model of AIH is established induced by concanavalin A (ConA). Mass cytometry and single-cell RNA sequencing (scRNA-seq) are used to analyze the potential role of ASX in regulating the immune microenvironment of AIH. ASX treatment effectively alleviated liver damage induced by ConA and downregulated pro-inflammatory cytokines production in mice. Mass cytometry and scRNA-seq analyses revealed a significant increase in the number of CD8+ T cells following ASX treatment. Functional markers of CD8+ T cells, such as CD69, MHC II, and PD-1, are significantly downregulated. Additionally, specific CD8+ T cell subclusters (subclusters 4, 13, 24, and 27) are identified, each displaying distinct changes in marker gene expression after ASX treatment. This finding suggests a modulation of CD8+ T cell function by ASX. Finally, the key transcription factors for four subclusters of CD8+ T cells are predicted and constructed a cell-to-cell communication network based on receptor-ligand interactions probability. In conclusion, ASX holds the potential to ameliorate liver damage by regulating the number and function of CD8+ T cells.

The molecular mechanism of obesity: The science behind natural exercise yoga and healthy diets in the treatment of obesity

The review centers on the scientific evidence underlying obesity, providing a detailed examination of the role of perilipin in this condition. It explores potential causes of obesity and delves into therapeutic approaches involving exercise, yoga, and herbal treatments. The paper discusses natural sources that can contribute to combating obesity and underscores the importance of exercise in a scientific context for overcoming obesity. Additionally, it includes information on herbal ingredients that aid in reducing obesity. The review also examines the impact of exercise type and intensity at various time intervals on muscle development. It elucidates triglyceride hydrolysis through different enzymes and the deposition of fatty acids in adipose tissue. The mechanisms by which alpha/beta hydrolase domain-containing protein 5 (ABHD5) and hormone-sensitive lipase (HSL) target and activate their functions are detailed. The inflammatory response in obesity is explored, encompassing inflammatory markers, lipid storage diseases, and their classification with molecular mechanisms. Furthermore, the hormonal regulation of lipolysis is elaborated upon in the review.

Astaxanthin Ameliorates Worsened Muscle Dysfunction of MDX Mice Fed with a High-Fat Diet through Reducing Lipotoxicity and Regulating Gut Microbiota

Duchenne muscular dystrophy (DMD), a severe X-linked inherited neuromuscular disease, has a high prevalence of obesity. Obesity exacerbates muscle damage and results in adverse clinical outcomes. Preventing obesity helps DMD patients delay disease progression and improve quality of life. Astaxanthin (AX) is a kind of carotenoid which has antioxidant and anti-adipogenesis effects. In this study, male C57BL/10ScSnDmdmdx/J mice were fed with a normal diet, a high-fat diet (HFD), and an HFD containing AX for 16 weeks, respectively. The results showed that AX significantly increased gastrocnemius fiber cross-section area and grip strength, improved treadmill endurance test and mitochondrial morphology, and reduced muscle triglyceride and malonaldehyde levels compared to the HFD. Lipidomic analysis revealed that AX decreased high levels of triglyceride, diglyceride, ceramides, and wax ester induced by HFD. Gut microbiota analysis indicated that AX supplementation failed to alleviate abnormal microbiota diversity, but increased the relative abundances of Akkermansia, Bifidobacterium, Butyricicoccus, and Staphylococcus. In conclusion, AX was expected to alleviate disease progression associated with obesity in DMD patients by reducing lipotoxicity and increasing the abundance of beneficial bacteria.

Effects of shrimp oil on cardio-metabolic risk factors in children and adolescents

Background: Antioxidants have beneficial effects on health. Shrimp oil has Astaxanthin and omega 3 that act as powerful antioxidants and might have anti-inflammatory effects on cardiovascular diseases. This study aims to investigate the effects of shrimp oil supplementation on cardio-metabolic risk factors in overweight and obese children and adolescents. Methods: This randomized, triple-blind, placebo-controlled clinical trial was conducted on 64 overweight and obese participants with 10-18 years of age. They were randomly assigned to receive either 500 mg shrimp oil or identical placebo that contained medium-chain triglycerides once per day for eight weeks. Dietary intake was obtained using food record questionnaire for three days at baseline and at the end of the study. Fasting blood samples were obtained at baseline and after eight weeks of intervention. Results: Overall, 53 participants completed the study; 30 subjects received shrimp oil and 23 subjects received placebo. There were no significant effects of shrimp oil on total cholesterol, triglyceride, HDL-C, LDL-C and blood pressure compared with the placebo group (p>0.05). Shrimp oil had no significant effects on body mass index, waist circumference and hip circumference compared with the placebo group (p>0.05). Conclusions: Supplementation with shrimp oil had no significant effects on improving the anthropometric measures and cardio-metabolic risk factors. Future clinical trials are needed to investigate the beneficial effects of higher doses of shrimp oil on cardio-metabolic risk factors in the pediatric age groups.

Astaxanthin: Past, Present, and Future

Astaxanthin (AX), a lipid-soluble pigment belonging to the xanthophyll carotenoids family, has recently garnered significant attention due to its unique physical properties, biochemical attributes, and physiological effects. Originally recognized primarily for its role in imparting the characteristic red-pink color to various organisms, AX is currently experiencing a surge in interest and research. The growing body of literature in this field predominantly focuses on AXs distinctive bioactivities and properties. However, the potential of algae-derived AX as a solution to various global environmental and societal challenges that threaten life on our planet has not received extensive attention. Furthermore, the historical context and the role of AX in nature, as well as its significance in diverse cultures and traditional health practices, have not been comprehensively explored in previous works. This review article embarks on a comprehensive journey through the history leading up to the present, offering insights into the discovery of AX, its chemical and physical attributes, distribution in organisms, and biosynthesis. Additionally, it delves into the intricate realm of health benefits, biofunctional characteristics, and the current market status of AX. By encompassing these multifaceted aspects, this review aims to provide readers with a more profound understanding and a robust foundation for future scientific endeavors directed at addressing societal needs for sustainable nutritional and medicinal solutions. An updated summary of AXs health benefits, its present market status, and potential future applications are also included for a well-rounded perspective.

Astaxanthin reduces fat storage in a fat-6/fat-7 dependent manner determined using high fat Caenorhabditis elegans

Although astaxanthin has been shown to have high potential for weight loss, the specific action site and signal pathway generally cannot be confirmed in other animal models. This prevents us from finding therapeutic targets. Hence, we further illuminated its efficacy and specific action sites by using Caenorhabditis elegans (C. elegans). In this study, 60 μM astaxanthin supplementation reduced overall fat deposition and triglyceride levels by 21.47% and 22.00% (p < 0.01). The content of large lipid droplets was reversed after astaxanthin treatment, and the ratio of oleic acid/stearic acid (C18:1Δ9/C18:0) decreased significantly, which were essential substrates for triglyceride biosynthesis. In addition, astaxanthin prevented obesity caused by excessive energy accumulation and insufficient energy consumption. Furthermore, the above effects were induced by sbp-1/mdt-15 and insulin/insulin-like growth factor pathways, and finally co-regulated the specific site-fat-6 and fat-7 down-regulation. These results provided insight into therapeutic targets for future astaxanthin as a nutritional health product to relieve obesity.

Roles of Marine Macroalgae or Seaweeds and Their Bioactive Compounds in Combating Overweight, Obesity and Diabetes: A Comprehensive Review

Obesity and diabetes are matters of serious concern in the health sector due to their rapid increase in prevalence over the last three decades. Obesity is a severe metabolic problem that results in energy imbalance that is persistent over a long period of time, and it is characterized by insulin resistance, suggesting a strong association with type 2 diabetes (T2D). The available therapies for these diseases have side effects and some still need to be approved by the Food and Drug Administration (FDA), and they are expensive for underdeveloped countries. Hence, the need for natural anti-obesity and anti-diabetic drugs has increased in recent years due to their lower costs and having virtually no or negligible side effects. This review thoroughly examined the anti-obesity and anti-diabetic effects of various marine macroalgae or seaweeds and their bioactive compounds in different experimental settings. According to the findings of this review, seaweeds and their bioactive compounds have been shown to have strong potential to alleviate obesity and diabetes in both in vitro and in vivo or animal-model studies. However, the number of clinical trials in this regard is limited. Hence, further studies investigating the effects of marine algal extracts and their bioactive compounds in clinical settings are required for developing anti-obesity and anti-diabetic medicines with better efficacy but lower or no side effects.

Obesity-Linked PPARγ Ser273 Phosphorylation Promotes Beneficial Effects on the Liver, despite Reduced Insulin Sensitivity in Mice

Since the removal of thiazolidinediones (TZDs) from the market, researchers have been exploring alternative anti-diabetic drugs that target PPARγ without causing adverse effects while promoting insulin sensitization by blocking serine 273 phosphorylation (Ser273 or S273). Nonetheless, the underlying mechanisms of the relationship between insulin resistance and S273 phosphorylation are still largely unknown, except for the involvement of growth differentiation factor (GDF3) regulation in the process. To further investigate potential pathways, we generated a whole organism knockin mouse line with a single S273A mutation (KI) that blocks the occurrence of its phosphorylation. Our observations of KI mice on different diets and feeding schedules revealed that they were hyperglycemic, hypoinsulinemic, presented more body fat at weaning, and presented an altered plasma and hepatic lipid profile, distinctive liver morphology and gene expression. These results suggest that total blockage of S273 phosphorylation may have unforeseen effects that, in addition to promoting insulin sensitivity, could lead to metabolic disturbances, particularly in the liver. Therefore, our findings demonstrate both the beneficial and detrimental effects of PPAR S273 phosphorylation and suggest selective modulation of this post translational modification is a viable strategy to treat type 2 diabetes.

Saccharified and Fermented Helianthus tuberosus L. Beverage Attenuates High-Fat Diet-Inducible Metabolic Complications in C57BL/6 Mice

The prevalence of obesity has been recognized as a major public health issue with rapid increase globally. Obesity triggers other metabolic complications, such as diabetes, dyslipidemia, liver diseases, and cardiovascular diseases. Helianthus tuberosus L. (the Jerusalem artichoke) is an important edible plant that may provide health benefits in treating metabolic diseases. In this study, we investigated potential antiobesity effects of saccharified H. tuberosus L. (SH) and its fermented vinegar (fermented H. tuberosus L. [FH]) in a high-fat diet (HFD)-induced obesity murine model. FH exhibited significantly lower pH, Brix, and total sugar content compared with the SH, along with higher radical-scavenging activity. The body weight and adipose tissue weights were significantly decreased with the administration of SH and FH compared with the HFD group. SH and FH groups significantly attenuated hepatomegaly and lipid accumulation. The increased triglyceride (TG) content in obese mice was remarkably lower in the SH and FH groups. SH and FH alleviated serum dyslipidemia and atherogenic risk. Furthermore, expression of adipogenic genes was significantly downregulated after SH and FH supplementation compared with the HFD group. The TG and total cholesterol (TC) content of serum and adipose tissues significantly decreased by SH and FH administration in comparison with the HFD group. Reduced adiposity with SH and FH administration was confirmed by reduced adipocyte size and weight with inhibition of lipoprotein lipase expression. Our study showed that SH and FH, indeed FH was superior to SH, had antiobesity effects by decreasing adiposity, regulating dyslipidemia in systemic tissues, and inhibiting adipogenic gene expression.

Egg laying performance and egg quality with Paracoccus carotinifaciens supplementation containing high astaxanthin levels

1. This study assessed 1) the effects of Paracoccus carotinifaciens supplementation containing high astaxanthin levels on egg production performance and quality, 2) dynamics of carotenoids levels in the egg yolk and 3) taste of astaxanthin-rich egg yolk.2. Laying hens were fed diets containing different levels of P. carotinifaciens-derived astaxanthin (ASX; 0, 2, 4, 8, or 16 ppm) for 28 d (experiment 1) or a diet containing 16 ppm astaxanthin for 28 d followed by a 0 ppm astaxanthin diet for 28 days (experiment 2).3. Production performance, egg quality and egg yolk carotenoid levels were examined in experiment 1 (Ex1) and the dynamics of egg yolk carotenoid levels and egg yolk taste in experiment 2 (Ex2).4. ASX supplementation did not affect production performance or egg quality. ASX levels in the egg yolk became saturated after seven days of 16 ppm supplementation and decreased to less than one-tenth of the saturated levels seven days after supplementation cessation. Supplementation with 16 ppm ASX for 28 d did not affect egg yolk taste.5. Supplementation resulted in the production of ASX-rich eggs for a brief period without affecting production performance, egg quality or taste. Understanding the time taken for the incorporation of ASX into egg yolks is beneficial for value-added egg production and may help in minimising supplementation costs.

More Than an Antioxidant: Role of Dietary Astaxanthin on Lipid and Glucose Metabolism in the Liver of Rainbow Trout (Oncorhynchus mykiss)

This study investigated the influence of dietary astaxanthin (AX) on glucose and lipid metabolism in rainbow trout liver. Two iso-nitrogenous and iso-lipidic diets were tested for 12 weeks in rainbow trout with an initial mean weight of 309 g. The S-ASTA diet was supplemented with 100 mg of synthetic AX per kg of feed, whereas the control diet (CTRL) had no AX. Fish fed the S-ASTA diet displayed lower neutral and higher polar lipids in the liver, associated with smaller hepatocytes and lower cytoplasm vacuolization. Dietary AX upregulated adipose triglyceride lipase (atgl), hormone-sensitive lipase (hsl2) and 1,2-diacylglycerol choline phosphotransferase (chpt), and downregulated diacylglycerol acyltransferase (dgat2), suggesting the AX's role in triacylglycerol (TAG) turnover and phospholipid (PL) synthesis. Dietary AX may also affect beta-oxidation with the upregulation of carnitine palmitoyltransferase 1 (cpt1α2). Although hepatic cholesterol levels were not affected, dietary AX increased gene expression of sterol regulatory element-binding protein 2 (srebp2). Dietary AX upregulated the expression of 6-phosphogluconate dehydrogenase (6pgdh) and downregulated pyruvate kinase (pkl). Overall, results suggest that dietary AX modulates the oxidative phase of the pentose phosphate pathway and the last step of glycolysis, affecting TAG turnover, β-oxidation, PL and cholesterol synthesis in rainbow trout liver.

A protein- and fiber-rich diet with astaxanthin alleviates high-fat diet-induced obesity in beagles

Background and aims

Overweight or obesity is one of the most prevalent health burdens in companion pets and predisposes subjects to multiple comorbidities and reduced longevity. Dietary management and sufficient exercise are effective options for weight loss but challenged by modern lifestyle and calorie control-triggered malnutrition. Therefore, this study aimed to develop a formulated obesity control diet characterized by protein- and fiber-rich diet and supplemented with astaxanthin. We systemically evaluated global influences of the designed weight-loss diet on metabolic homeostasis in an obese beagle model.

Materials and methods

Beagles were induced for obesity by a 24-week HFD treatment and then included into weight-loss programs. Briefly, obese beagles were randomly assigned to two groups that were fed with a formulated weight-loss diet or control diet, respectively. Body weight and body condition scoring (BCS) were analyzed biweekly. Computed tomography (CT), nuclear magnetic resonance imaging (MRI) measurements, and blood and adipose tissue biopsies were collected at 0 and 8 weeks. Plasma lipids and adipocyte size were also measured after 8 weeks of weight-loss diet feeding. The global influence of the formulated diet on the whole spectrum of gene panels were examined by adipose RNA assays.

Results

Twenty-four weeks of continuous HFD feeding significantly induced obesity in beagles, as evidenced by increased body weight, BCS, abdominal fat mass, and serum lipid levels. The obese and metabolic condition of the modeled canine were effectively improved by an 8-week weight-loss diet administration. Importantly, we did not observe any side effects during the weight loss duration. Transcriptional analysis of adipose tissues further supported that a weight-loss diet significantly increased energy metabolism-related pathways and decreased lipid synthesis-related pathways.

Conclusion

The prescribed weight-loss diet exhibited profound benefits in canine weight management with well safety and palatability. These findings support effective strategies of nutritional management and supplementation approaches for weight control in companion animals.

Preventive and Therapeutic Effects of Krill Oil on Obesity and Obesity-Induced Metabolic Syndromes in High-Fat Diet-Fed Mice

Obesity increases the risks of metabolic syndromes including nonalcoholic fatty liver disease (NAFLD), diabetic dyslipidemia, and chronic kidney disease. Dietary krill oil (KO) has shown antioxidant and anti-inflammatory properties, thereby being a therapeutic potential for obesity-induced metabolic syndromes. Thus, the effects of KO on lipid metabolic alteration were examined in a high-fat diet (HFD)-fed mice model. The HFD model (n = 10 per group) received an oral gavage with distilled water as a control, metformin at 250 mg/kg, and KO at 400, 200, and 100 mg/kg for 12 weeks. The HFD-induced weight gain and fat deposition were significantly reduced in the KO treatments compared with the control. Blood levels were lower in parameters for NAFLD (e.g., alanine aminotransferase, and triglyceride), type 2 diabetes (e.g., glucose and insulin), and renal dysfunction (e.g., blood urea nitrogen and creatinine) by the KO treatments. The KO inhibited lipid synthesis through the modification of gene expressions in the liver and adipose tissues and adipokine-mediated pathways. Furthermore, KO showed hepatic antioxidant activities and glucose lowering effects. Histopathological analyses revealed that the KO ameliorated the hepatic steatosis, pancreatic endocrine/exocrine alteration, adipose tissue hypertrophy, and renal steatosis. These analyses suggest that KO may be promising for inhibiting obesity and metabolic syndromes.

The Role of Macrophages in Liver Fibrosis: New Therapeutic Opportunities

Chronic inflammation is the hallmark of fibrotic disorders and is characterized by the activation of immune cells in the damaged tissues. Macrophages have emerged as central players in the fibrotic process since they initiate, sustain and amplify the inflammatory reaction. As regards the liver, distinct populations of phagocytic cells, like Kupffer cells and monocyte-derived macrophages, are indisputably key cells implicated in the pathogenesis of several chronic liver diseases. In this review, we summarize the current knowledge on the origin, role and functions of macrophages in fibrotic conditions, with a specific focus on liver fibrosis; then, we discuss some innovative therapeutic strategies targeting macrophages in fibrotic liver diseases.

Ferulic acid and berberine, via Sirt1 and AMPK, may act as cell cleansing promoters of healthy longevity

Ferulic acid, a bacterial metabolite of anthocyanins, seems likely to be a primary mediator of the health benefits associated with anthocyanin-rich diets, and has long been employed in Chinese cardiovascular medicine. In rodent studies, it has exerted wide-ranging antioxidant and anti-inflammatory effects, the molecular basis of which remains rather obscure. However, recent studies indicate that physiologically relevant concentrations of ferulic acid can boost expression of Sirt1 at mRNA and protein levels in a range of tissues. Sirt1, a class III deacetylase, functions to detect a paucity of oxidisable substrate, and in response works in various ways to promote cellular survival and healthful longevity. Sirt1 promotes ‘cell cleansing’ and cell survival by boosting autophagy, mitophagy, mitochondrial biogenesis, phase 2 induction of antioxidant enzymes via Nrf2, and DNA repair—while inhibiting NF-kB-driven inflammation, apoptosis, and cellular senescence, and boosting endothelial expression of the protective transcription factor kruppel-like factor 2. A deficit of the latter appears to mediate the endothelial toxicity of the SARS-CoV-2 spike protein. Ferulic acid also enhances the activation of AMP-activated kinase (AMPK) by increasing expression and activity of its activating kinase LKB1—whereas AMPK in turn amplifies Sirt1 activity by promoting induction of nicotinamide phosphoribosyltranferase, rate-limiting for generation of Sirt1’s obligate substrate NAD+. Curiously, AMPK acts by independent mechanisms to potentiate many of the effects mediated by Sirt1. Hence, it is proposed that ferulic acid may exert complementary or synergistic health-promoting effects when used in conjunction with clinically useful AMPK activators, such as the nutraceutical berberine. Additional nutraceuticals which might have potential for amplifying certain protective effects of ferulic acid/berberine are also discussed.

Possible Effect of Astaxanthin on Obesity-related Increased COVID-19 Infection Morbidity and Mortality

Abstract:

Obesity is defined by the World Health Organisation (WHO) as a body mass index equal to 30 kg/m2 or greater. It is an important and escalating global public health problem. Obesity is known to cause low-grade chronic inflammation, increasing the burden of noncommunicable and possibly communicable diseases. There is considerable evidence that obesity is associated with an increased risk of contracting coronavirus disease 2019 (COVID-19) infection as well as significantly higher COVID-19 morbidity and mortality. It appears plausible that controlling the chronic systemic low-grade inflammation associated with obesity may have a positive impact on the symptoms and the prognosis of COVID-19 disease in obese patients. Astaxanthin (ASTX) is a naturally occurring carotenoid with anti-inflammatory, antioxidant, and immunomodulatory activities. As a nutraceutical agent, it is used as a preventative and a co-treatment in a number of systemic neurological, cardiovascular, and metabolic diseases. This review article will discuss the pathogenesis of COVID-19 infection and the effect of ASTX on obesity and obesity-related inflammation. The potential positive impact of ASTX anti- inflammatory properties in obese COVID-19 patients will be discussed.

Mechanistic role of astaxanthin derived from shrimp against certain metabolic disorders

Oxidative stress caused by the imbalance between production of oxidants and antioxidants in the body leads to the development of different ailments. The bioactive compounds derived from marine sources are considered to be safe and appropriate to use. Astaxanthin possesses antioxidant activity about 100-500 times higher than other antioxidants such as α-tocopherol and β-carotene. It has numerous health benefits and vital pharmacological properties for the treatment of diseases like diabetes, hypertension, cancer, heart disease, ischemia, neurological disorders, and potential role in liver enzyme gamma-glutamyl transpeptidase which has significance in medicine as a diagnostic marker. The primary source of astaxanthin among crustaceans is shrimps and the presence of astaxanthin protects shrimps from oxidation of polyunsaturated fatty acids and cholesterol. Conclusively, astaxanthin derived from shrimps is very effective against oxidative stress which can lead to certain ailments.

Astaxanthin attenuates hepatic steatosis in high-fat diet-fed rats by suppressing microRNA-21 via transactivation of nuclear factor erythroid 2-related factor 2

This study examined whether astaxanthin (ASX) could alleviate hepatic steatosis in rats fed a high-fat diet (HFD) by modulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/miR-21 axis. Rats (n = 8/group) were fed either a standard diet (3.8 kcal/g; 10% fat) or HFD (4.6 kcal/g; 40% fat) and treated orally with either the vehicle or ASX (6 mg/kg) daily for 8 days. Another group was fed HFD and treated with ASX and brusatol (an Nrf2 inhibitor) (2 mg/kg/twice per week/i.p.). ASX prevented the gain in body and liver weights and attenuated hepatic lipid accumulation in HFD-fed rats. In the control and HFD-fed rats, ASX did not affect food intake, serum free fatty acid (FFA) content, and glucose and insulin levels and tolerance. However, serum triglyceride (TG), cholesterol, and low-density lipoprotein-cholesterol levels; hepatic levels of TGs and FFAs; and hepatic levels of Srebp1, Srebp2, HMGCR, and fatty acid synthase mRNAs and miR-21 were reduced and the mRNA levels of Pparα were significantly increased in both the groups. These effects were associated with a reduction in the hepatic levels of reactive oxygen species, malondialdehyde, tumor necrosis factor-α, and interlukin-6 as well as an increase in superoxide dismutase levels, total glutathione content, and nuclear levels and activity of Nrf2. miR-21 levels were strongly correlated with the nuclear activity of Nrf2. Brusatol completely reversed the effects of ASX. In conclusion, ASX prevents hepatic steatosis mainly by transactivating Nrf2 and is associated with the suppression of miR-21 and Srebp1/2 and upregulation of Pparα expression.

Effects of astaxanthin in animal models of obesity-associated diseases: A systematic review and meta-analysis

BACKGROUND AND AIM

Obesity is a major risk factor for several diseases, including metabolic syndrome (MetS), non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D). The use of natural products, such as astaxanthin (ASX), a potent antioxidant compound produced by the freshwater green microalga Haematococcus pluvialis, has gained particular interest to reduce oxidative stress and inflammation, and to improve redox status, often associated with obesity. A systematic review and meta-analysis was performed to comprehensively examine the effects of ASX in animal models of diet induced obesity-associated diseases in order to inform the design of future human clinical studies for ASX use as supplement or nutraceutical.

METHODS

Cinahl, Cochraine, MEDLINE, Scopus and Web of Science were searched for English-language manuscripts published between January 2000 and April 2020 using the following key words: astaxanthin, obesity, non-alcoholic fatty liver disease, diabetes mellitus type 2, NAFLD and metabolic.

RESULTS

Seventeen eligible articles, corresponding to 21 animal studies, were included in the final quantitative analysis. ASX, at different concentrations and administered for different length of time, induced a significant reduction in adipose tissue weight (P = 0.05) and systolic blood pressure (P < 0.0001) in control animals. In animal models of T2D, ASX significantly reduced serum glucose levels (P = 0.04); whereas it improved several disease biomarkers in the blood (e.g. cholesterol, triglycerides, ALT and AST, P < 0.10), and reduced liver (P = 0.0002) and body weight (P = 0.11), in animal models of NAFLD.

CONCLUSIONS

Supplementation of ASX in the diet has positive effects on symptoms associated with obesity related diseases in animals, by having lipid-lowering, hypo-insulin and hypoglycaemic capacity, protecting organs from oxidative stress and mitigating the immune system, as suggested in this review.

Beneficial effects and health benefits of Astaxanthin molecules on animal production: A review

Astaxanthin (AST) is a red pigment of carotenoid and is considered a high-quality keto-carotenoid pigment with food, livestock, cosmetic, therapeutic and nutraceutical proposes. Astaxanthin exists naturally in fish, crustacean, algae, and birds that naturally exists, principally as fatty acid esters. Many investigations have exhibited the beneficial impacts of astaxanthin when utilized as a pharmaceutical agent in animal nutrition. Astaxanthin has a variety of considerable biological actions, such as being antihypertensive, an antioxidant, anti-obesity properties, and anti-carcinogenic. Astaxanthin has recently acquired popularity as a powerful immunomodulator to maintain the health status and well-being of both animals and humans. The use of astaxanthin is broadly utilized in medical sciences and the nutrition pf aquatic species; however, it presently has limited applications in broader animal nutrition. Understanding astaxanthin's structure, source, and mode of action in the body provides a conceptual base for its clinical application and could enhance the screening of compounds associated with the treatment of many diseases. This review article aims to clarify the important aspects of astaxanthin such as its synthesis, bioavailability, and therapeutics actions, with special interest in practical applications. Awareness of this benefits and production is expected to aid the livestock industry to develop nutritional strategies that ensure the protection of animal health.

Anti-diabetic effects of astaxanthin on an STZ-induced diabetic model in rats

Type 2 diabetes mellitus (T2DM), which is characterized by insulin resistance and relative insulin insufficiency, has become the most common chronic metabolic disease threatening global health. The preferred therapies for T2DM include lifestyle interventions and the use of anti-diabetic drugs. However, considering their adverse reactions, it is important to find a low-toxicity and effective functional food or drug for diabetes prevention and treatment. Astaxanthin is a potent antioxidant carotenoid found in marine organisms has been reported to prevent diet-induced insulin resistance and hepatic steatosis. To investigate the anti-diabetic effects of astaxanthin, male Wistar rats were fed a high-energy diet for 4 weeks, followed by a low dose streptozotocin (STZ) injection to induce the diabetes model, and the rats were then fed an astaxanthin-containing diet for another 3 weeks. Astaxanthin significantly decreased blood glucose and total cholesterol (TC) levels, and increased blood levels of high density lipoprotein cholesterol (HDL-C) in STZ-induced diabetic rats in a dose dependent manner. These results were associated with increased expression of insulin sensitivity related genes (adiponectin, adipoR1, and adipoR2) in vivo, thereby attenuating STZ-induced diabetes. In addition, we also compared the anti-diabetic effects of astaxanthin and monacolin K, which has been reported to downregulate hyperlipidemia and hyperglycemia. The results revealed that astaxanthin and monacolin K showed similar anti-diabetic effects in STZ-induced diabetic rats. Therefore, astaxanthin may be developed as an anti-diabetic agent in the future.

Inflammation/bioenergetics-associated neurodegenerative pathologies and concomitant diseases: a role of mitochondria targeted catalase and xanthophylls

Various inflammatory stimuli are able to modify or even "re-program" the mitochondrial metabolism that results in generation of reactive oxygen species. In noncommunicable chronic diseases such as atherosclerosis and other cardiovascular pathologies, type 2 diabetes and metabolic syndrome, these modifications become systemic and are characterized by chronic inflammation and, in particular, "neuroinflammation" in the central nervous system. The processes associated with chronic inflammation are frequently grouped into "vicious circles" which are able to stimulate each other constantly amplifying the pathological events. These circles are evidently observed in Alzheimer's disease, atherosclerosis, type 2 diabetes, metabolic syndrome and, possibly, other associated pathologies. Furthermore, chronic inflammation in peripheral tissues is frequently concomitant to Alzheimer's disease. This is supposedly associated with some common genetic polymorphisms, for example, Apolipoprotein-E ε4 allele carriers with Alzheimer's disease can also develop atherosclerosis. Notably, in the transgenic mice expressing the recombinant mitochondria targeted catalase, that removes hydrogen peroxide from mitochondria, demonstrates the significant pathology amelioration and health improvements. In addition, the beneficial effects of some natural products from the xanthophyll family, astaxanthin and fucoxanthin, which are able to target the reactive oxygen species at cellular or mitochondrial membranes, have been demonstrated in both animal and human studies. We propose that the normalization of mitochondrial functions could play a key role in the treatment of neurodegenerative disorders and other noncommunicable diseases associated with chronic inflammation in ageing. Furthermore, some prospective drugs based on mitochondria targeted catalase or xanthophylls could be used as an effective treatment of these pathologies, especially at early stages of their development.

Prevention of NAFLD/NASH by Astaxanthin and β-Cryptoxanthin

Metabolic disorders, such as lipid accumulation, insulin resistance, and inflammation, have been implicated in the pathogenesis of NAFLD/NASH. Both innate and recruited immune cells mediate the development of insulin resistance and NASH. Oxidative stress is also pivotal for the progression of NASH. Astaxanthin is a natural carotenoid mainly derived from microorganisms and marine organisms. Due to its special chemical structure, astaxanthin has strong antioxidant activity. β-Cryptoxanthin is a xanthophyll carotenoid specifically found in the Satsuma mandarin. β-Cryptoxanthin is readily absorbed and relatively abundant in human plasma, together with α-carotene, β-carotene, lycopene, lutein, and zeaxanthin. Considering the unique chemical properties of astaxanthin and β-cryptoxanthin and the complex pathogenic mechanism of NASH, astaxanthin and β-cryptoxanthin are regarded as a considerable compound for the prevention and treatment of NASH. This chapter comprehensively describes the mechanism of the application for astaxanthin and β-cryptoxanthin on the prevention and treatment of NASH from the aspects, including antioxidative stress, inhibition of inflammation and promotion of M2 macrophage polarization, improvement of mitochondrial oxidative respiration, amelioration of insulin resistance, and suppression of fibrosis.

Dietary Supplementation of Astaxanthin Improved the Growth Performance, Antioxidant Ability and Immune Response of Juvenile Largemouth Bass (Micropterus salmoides) Fed High-Fat Diet

High-fat diet (HFD) usually induces oxidative stress and astaxanthin is regarded as an excellent anti-oxidant. An 8-week feeding trial was conducted to investigate the effects of dietary astaxanthin supplementation on growth performance, lipid metabolism, antioxidant ability, and immune response of juvenile largemouth bass (Micropterus salmoides) fed HFD. Four diets were formulated: the control diet (10.87% lipid, C), high-fat diet (18.08% lipid, HF), and HF diet supplemented with 75 and 150 mg kg^-1 astaxanthin (HFA1 and HFA2, respectively). Dietary supplementation of astaxanthin improved the growth of fish fed HFD, also decreased hepatosomatic index and intraperitoneal fat ratio of fish fed HFD, while having no effect on body fat. Malondialdehyde content and superoxide dismutase activity were increased in fish fed HFD, astaxanthin supplementation in HFD decreased the oxidative stress of fish. The supplementation of astaxanthin in HFD also reduced the mRNA levels of Caspase 3, Caspase 9, BAD, and IL15. These results suggested that dietary astaxanthin supplementation in HFD improved the growth performance, antioxidant ability and immune response of largemouth bass.

Brown adipose tissue uptake of triglyceride-rich lipoprotein-derived fatty acids in diabetic or obese mice under different temperature conditions

Background

In vivo imaging of glucose analogue 2-deoxy-2-[¹⁸F]fluoro-d-glucose ([¹⁸F]FDG) via positron emission tomography (PET) is the current gold standard to visualize and assess brown adipose tissue (BAT) activity. However, glucose metabolism is only a part of the metabolic activity of BAT. [¹⁸F]FDG-PET has been shown in clinical trials to often fail to visualize BAT under insulin-resistant conditions associated with aging and weight gain. We employed a novel developed triglyceride-based tracer to visualize BATs metabolic activity under different temperature conditions as well as under diabetic and obese conditions in preclinical models.

Results

[¹⁸F]BDP-TG-chylomicron-like particles visualized BAT in control, streptozocin-induced diabetes and obese mice. Increased BAT tracer uptake was found in control mice acutely exposed to cold but not in cold-acclimated animals. Diabetes did not remove BAT tracer uptake, but did limit BAT tracer uptake to levels of control mice housed at 21 °C. In obese animals, BAT tracer uptake was significantly reduced, although the stimulating effect of cold exposure could still be noted.

Conclusion

BAT was visualized in control, diabetic and obese conditions. Streptozocin-induced diabetes, but not obesity, inhibited the stimulatory effect of cold exposure.

Novel Insights into the Biotechnological Production of Haematococcus pluvialis-Derived Astaxanthin: Advances and Key Challenges to Allow Its Industrial Use as Novel Food Ingredient

Astaxanthin shows many biological activities. It has acquired a high economic potential and its current market is dominated by its synthetic form. However, due to the increase of the health and environmental concerns from consumers, natural forms are now preferred for human consumption. Haematococcus pluvialis is artificially cultured at an industrial scale to produce astaxanthin used as a dietary supplement. However, due to the high cost of its cultivation and its relatively low biomass and pigment productivities, the astaxanthin extracted from this microalga remains expensive and this has probably the consequence of slowing down its economic development in the lower added-value market such as food ingredient. In this review, we first aim to provide an overview of the chemical and biochemical properties of astaxanthin, as well as of its natural sources. We discuss its bioavailability, metabolism, and biological activities. We present a state-of-the-art of the biology and physiology of H. pluvialis, and highlight novel insights into the biotechnological processes which allow optimizing the biomass and astaxanthin productivities. We are trying to identify some lines of research that would improve the industrial sustainability and economic viability of this bio-production and to broaden the commercial potential of astaxanthin produced from H. pluvialis.

Effect of Astaxanthin on the Expression and Activity of Aquaporin-3 in Skin in an In-Vitro Study

Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione) is a red lipophilic pigment with strong antioxidant action. Oral or topical administration of astaxanthin has been reported to improve skin function, including increasing skin moisture. In this study, we examined the mechanism by which astaxanthin improves skin function by focusing on the water channel aquaporin-3 (AQP3), which plays important roles in maintaining skin moisture and function. When astaxanthin was added to PHK16-0b or HaCaT cells, the mRNA expression level of AQP3 increased significantly in a concentration-dependent manner in both cell lines. The AQP3 protein expression level was also confirmed to increase when astaxanthin was added to HaCaT cells. Similarly, when astaxanthin was added to 3D human epidermis model EpiSkin, AQP3 expression increased. Furthermore, when glycerol and astaxanthin were simultaneously added to EpiSkin, glycerol permeability increased significantly compared with that observed for the addition of glycerol alone. We demonstrated that astaxanthin increases AQP3 expression in the skin and enhances AQP3 activity. This result suggests that the increased AQP3 expression in the skin is associated with the increase in skin moisture by astaxanthin. Thus, we consider astaxanthin useful for treating dry skin caused by decreased AQP3 due to factors such as diabetes mellitus and aging.

Astaxanthin and other Nutrients from Haematococcus pluvialis-Multifunctional Applications

Bioactive compounds of natural origin are gaining increasing popularity. High biological activity and bioavailability, beneficial effects on health and safety of use are some of their most desirable features. Low production and processing costs render them even more attractive. Microorganisms have been used in the food, medicinal, cosmetic and energy industries for years. Among them, microalgae have proved to be an invaluable source of beneficial compounds. Haematococcus pluvialis is known as the richest source of natural carotenoid called astaxanthin. In this paper, we focus on the cultivation methods of this green microalga, its chemical composition, extraction of astaxanthin and analysis of its antioxidant, anti-inflammatory, anti-diabetic and anticancer activities. H. pluvialis, as well as astaxanthin can be used not only for the treatment of human and animal diseases, but also as a valuable component of diet and feed.

Effect of Astaxanthin on the Inhibition of Lipid Accumulation in 3T3-L1 Adipocytes via Modulation of Lipogenesis and Fatty Acid Transport Pathways

Obesity is defined as a condition of excessive fat tissue accumulation. It was the major factor most closely associated with lifestyle-related diseases. In the present study, we investigated the effect of astaxanthin on the inhibition of lipid accumulation in 3T3-L1 adipocytes. 3T3-L1 adipocytes were treated with 0–25 µg/mL of astaxanthin for 0–48 h. The result indicated that astaxanthin significantly decreased the oil Red O stained material (OROSM), intracellular triglyceride accumulation, and glycerol 3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 adipocytes (p < 0.05). At the molecular level, astaxanthin significantly down-regulated the mRNA expression of peroxisome proliferator-activated receptor-γ (PPARγ) in 3T3-L1 adipocytes (p < 0.05). Moreover, target genes of PPARγ on the inhibition of lipogenesis, such as Acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), fatty acid binding protein (aP2), cluster of differentiation 36 (CD36), and lipoprotein lipase (LPL) in 3T3-L1 adipocytes were significantly down-regulated at a time-dependent manner (p < 0.05). These results suggested that astaxanthin efficiently suppressed lipid accumulation in 3T3-L1 adipocytes and its action is associated with the down-regulation of lipogenesis-related genes and the triglyceride accumulation in 3T3-L1 adipocytes. Therefore, astaxanthin can be developed as a potential nutraceutical ingredient for the prevention of obesity in a niche market.

Effects of Exercise Combined with a Healthy Diet or Calanus finmarchicus Oil Supplementation on Body Composition and Metabolic Markers-A Pilot Study

Aging is accompanied by a progressive decline in muscle mass and an increase in fat mass, which are detrimental changes associated with the development of health conditions such as type-2 diabetes mellitus or chronic low-grade inflammation. Although both exercise as well as nutritional interventions are known to be beneficial in counteracting those age-related changes, data to which extent untrained elderly people may benefit is still sparse. Therefore, a randomized, controlled, 12-week interventional trial was conducted in which 134 healthy untrained participants (96 women and 38 men, age 59.4 ± 5.6 years, body mass index (BMI) 28.4 ± 5.8 kg/m²) were allocated to one of four study groups: (1) control group with no intervention (CON); (2) 2×/week aerobic and resistance training only (EX); (3) exercise routine combined with dietary counseling in accordance with the guidelines of the German Nutrition Society (EXDC); (4) exercise routine combined with intake of 2 g/day oil from Calanus finmarchicus (EXCO). Body composition (bioelectrical impedance analysis), as well as markers of glucose metabolism and blood lipids, were analyzed at the beginning and the end of the study. The highest decreases in body fat were observed within the EXCO group (−1.70 ± 2.45 kg, p < 0.001), and the EXDC (−1.41 ± 2.13 kg, p = 0.008) group. Markers of glucose metabolism and blood lipids remained unchanged in all groups. Taken together results of this pilot study suggest that a combination of moderate exercise and intake of oil from Calanus finmarchicus or a healthy diet may promote fat loss in elderly untrained overweight participants.

Dietary supplemental microalgal astaxanthin modulates molecular profiles of stress, inflammation, and lipid metabolism in broiler chickens and laying hens under high ambient temperatures

This research was to determine effects of supplemental dietary microalgal astaxanthin (AST) on hepatic gene expression and protein production of redox enzymes, heat shock proteins (HSPs), cytokines, and lipid metabolism in broilers (BR) and laying hens (LH) under high ambient temperatures. A total of 240 (day old) Cornish male BR and 50 (19 wk old) White Leghorn Shavers LH were allotted in 5 dietary treatments with 6 and 10 cages/treatment (8 BR or 1 LH/cage), respectively. The birds were fed corn-soybean meal basal diets supplemented with microalgal (Haematococcus pluvialis) AST at 0, 10, 20, 40, and 80 mg/kg diet for 6 wk. Supplemental AST to the BR diet linearly decreased (P < 0.10, R² = 0.18–0.36) hepatic mRNA levels of several redox status-controlling genes, heat shock protein 70 (HSP70), heat shock transcription factor 1 (HSTF1), c-Jun N-terminal kinase 1 (JNK1), tumor necrosis factor-α, and sterol regulatory element-binding protein 1 (SREBP1). The supplementation linearly elevated (P = 0.04, R² = 0.20) diacylglycerol acyltransferase 2 (DGAT2) mRNA level and produced quadratic changes (P < 0.10, R² = 0.15–0.47) in mRNA levels of glutathione S-transferase (GST), serine/threonine kinase (AKT1), P38 mitogen-activated protein kinase (P38MAKP), lipid metabolism–controlling genes, and the protein production of HSP90 and P38MAPK in the liver. Supplementing AST to the LH diets linearly decreased (P < 0.10, R² = 0.18–0.56) mRNA levels of GST, HSF1, JNK1, and interleukin 10; lipogenesis genes; and JNK1 protein production. However, supplemental dietary AST produced quadratic changes (P < 0.10, R² = 0.26–0.72) in mRNA levels of most antioxidant-, stress-responsive, and lipid metabolism–related genes in the liver of LH. In conclusion, supplemental dietary AST affected the hepatic gene expression and protein production related to redox status, heat stress and inflammation, and lipid metabolism in both BR and LH. The impacts varied with the chicken type and demonstrated linear and quadratic regressions with the inclusion levels of AST.

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.

Astaxanthin in Liver Health and Disease: A Potential Therapeutic Agent

Astaxanthin is a carotenoid derived from oxygen-containing non-vitamin A sources and is mainly obtained from marine organisms. Studies have demonstrated that astaxanthin is a natural antioxidant product and it is widely used in the fields of medicine, health-care products and cosmetics. Studies have shown that astaxanthin has important preventive and therapeutic effects on liver fibrosis, non-alcoholic fatty liver, liver cancer, drug and ischemia-induced liver injury, and its mechanism is related to antioxidant and anti-inflammatory activities, and the regulation of multiple signaling pathways. In this review, we discuss the latest data on astaxanthin in the prevention and treatment of liver diseases. An understanding of the structure, source and mechanism of action of astaxanthin in the body would not only provide a theoretical basis for its clinical application but could also have important significance in screening and improving related compounds for the treatment of liver diseases.

Antiplatelet activity of astaxanthin in control- and high cholesterol-fed rats mediated by down-regulation of P2Y12, inhibition of NF-κB, and increasing intracellular levels of cAMP

This study evaluated the antiplatelet effect of the plant carotenoid, astaxanthin (ASTX) in rats fed either control or high cholesterol plus cholic acid diet (HCCD) and possible underlying mechanisms. Adult male Wistar rats were divided into four groups (n = 8/each), namely, control (fed normal diet), control + ASTX (10 mg/kg/day), HCCD-fed rats, and HCCD + ASTX-treated rats. Diets and treatments were orally administered daily for 30 days. In both control and HCCD-fed rats, ASTX significantly increased fecal levels of triglycerides and cholesterol, reduced platelet count, prolonged bleeding time, and inhibited platelet aggregation. It also reduced platelet levels of reactive oxygen species (ROS) and Bcl-2; thromboxane B2 (TXB2) release; and the expression of P2Y₁₂, P-selectin, and CD36 receptors. Moreover, the activity NF-κB p65 and Akt was inhibited. Concomitantly, it increased the protein levels of cleaved caspase-3 and vasodilator-stimulated phosphoprotein (p-VASP) as well as intracellular levels of cAMP. However, in HCCD-fed rats, the effects of ASTX were associated with reduced serum levels of ox-LDL-c and fasting plasma glucose levels. In conclusion, antiplatelet effects of ASTX involve ROS scavenging, inhibiting NF-κB activity, down-regulating P2Y₁₂ expression, and increasing intracellular levels of cAMP that are attributed to its antioxidant, hypolipidemic, and anti-inflammatory effects.

Carotenoids and carotenoid conversion products in adipose tissue biology and obesity: Pre-clinical and human studies

Antiobesity activities of carotenoids and carotenoid conversion products (CCPs) have been demonstrated in pre-clinical studies, and mechanisms behind have begun to be unveiled, thus suggesting these compounds may help obesity prevention and management. The antiobesity action of carotenoids and CCPs can be traced to effects in multiple tissues, notably the adipose tissues. Key aspects of the biology of adipose tissues appear to be affected by carotenoid and CCPs, including adipogenesis, metabolic capacities for energy storage, release and inefficient oxidation, secretory function, and modulation of oxidative stress and inflammatory pathways. Here, we review the connections of carotenoids and CCPs with adipose tissue biology and obesity as revealed by cell and animal intervention studies, studies addressing the role of endogenous retinoid metabolism, and human epidemiological and intervention studies. We also consider human genetic variability influencing carotenoid and vitamin A metabolism, particularly in adipose tissues, as a potentially relevant aspect towards personalization of dietary recommendations to prevent or manage obesity and optimize metabolic health. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

Improved Tetanic Force and Mitochondrial Calcium Homeostasis by Astaxanthin Treatment in Mouse Skeletal Muscle

BACKGROUND

Astaxanthin (AX) a marine carotenoid is a powerful natural antioxidant which protects against oxidative stress and improves muscle performance. Retinol and its derivatives were described to affect lipid and energy metabolism. Up to date, the effects of AX and retinol on excitation-contraction coupling (ECC) in skeletal muscle are poorly described.

METHODS

18 C57Bl6 mice were divided into two groups: Control and AX supplemented in rodent chow for 4 weeks (AstaReal A1010). In vivo and in vitro force and intracellular calcium homeostasis was studied. In some experiments acute treatment with retinol was employed.

RESULTS

The voltage activation of calcium transients (V₅₀) were investigated in single flexor digitorum brevis isolated fibers under patch clamp and no significant changes were found following AX supplementation. Retinol shifted V₅₀ towards more positive values and decreased the peak F/F₀ of the calcium transients. The amplitude of tetani in the extensor digitorum longus was significantly higher in AX than in control group. Lastly, the mitochondrial calcium uptake was found to be less prominent in AX.

CONCLUSION

AX supplementation increases in vitro tetanic force without affecting ECC and exerts a protecting effect on the mitochondria. Retinol treatment has an inhibitory effect on ECC in skeletal muscle.

Carotenoids and fatty liver disease: Current knowledge and research gaps

Carotenoids form an important part of the human diet, consumption of which has been associated with many health benefits. With the growing global burden of liver disease, increasing attention has been paid on the possible beneficial role that carotenoids may play in the liver. This review focuses on carotenoid actions in non-alcoholic fatty liver disease (NAFLD), and alcoholic liver disease (ALD). Indeed, many human studies have suggested an association between decreased circulating levels of carotenoids and increased incidence of NAFLD and ALD. The literature describing supplementation of individual carotenoids in rodent models of NAFLD and ALD is reviewed, with particular attention paid to β-carotene and lycopene, but also including β-cryptoxanthin, lutein, zeaxanthin, and astaxanthin. The effect of beta-carotene oxygenase 1 and 2 knock-out mice on hepatic lipid metabolism is also discussed. In general, there is evidence to suggest that carotenoids have beneficial effects in animal models of both NAFLD and ALD. Mechanistically, these benefits may occur via three possible modes of action: 1) improved hepatic antioxidative status broadly attributed to carotenoids in general, 2) the generation of vitamin A from β-carotene and β-cryptoxanthin, leading to improved hepatic retinoid signaling, and 3) the generation of apocarotenoid metabolites from β-carotene and lycopene, that may regulate hepatic signaling pathways. Gaps in our knowledge regarding carotenoid mechanisms of action in the liver are highlighted throughout, and the review ends by emphasizing the importance of dose effects, mode of delivery, and mechanism of action as important areas for further study. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

Anti-Obesity Effect of Carotenoids: Direct Impact on Adipose Tissue and Adipose Tissue-Driven Indirect Effects

This review summarizes current knowledge on the biological relevance of carotenoids and some of their metabolites in obesity management. The relationship between carotenoids and obesity is considered in clinical studies and in preclinical studies. Adipose tissue is a key organ in obesity etiology and the main storage site for carotenoids. We thus first describe carotenoid metabolism in adipocyte and adipose tissue and the effects of carotenoids on biological processes in adipose tissue that may be linked to obesity management in in vitro and preclinical studies. It is also now well established that the brain is strongly involved in obesity processes. A section is accordingly devoted to the potential effect of carotenoids on obesity via their direct and/or adipose tissue-driven indirect biological effects on the brain.

Health Benefits of Carotenoids: A Role of Carotenoids in the Prevention of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases with a prevalence of ~25% worldwide. NAFLD includes simple hepatic steatosis, non-alcoholic steatohepatitis, fibrosis, and cirrhosis, which can further progress to hepatocellular carcinoma. Therefore, effective strategies for the prevention of NAFLD are needed. The pathogenesis of NAFLD is complicated due to diverse injury insults, such as fat accumulation, oxidative stress, inflammation, lipotoxicity, and apoptosis, which may act synergistically. Studies have shown that carotenoids, a natural group of isoprenoid pigments, prevent the development of NAFLD by exerting antioxidant, lipid-lowering, anti-inflammatory, anti-fibrotic, and insulin-sensitizing properties. This review summarizes the protective action of carotenoids, with primary focuses on astaxanthin, lycopene, β-carotene, β-cryptoxanthin, lutein, fucoxanthin, and crocetin, against the development and progression of NAFLD.

Xanthophyllomyces dendrorhous-Derived Astaxanthin Regulates Lipid Metabolism and Gut Microbiota in Obese Mice Induced by A High-Fat Diet

Astaxanthin is an important antioxidant with many biological activities such as anti-tumor, anti-obesity, cardioprotective, and immuno-modulatory activities. Most of these biological activities are derived from (3S,3'S)-astaxanthin, while the activities of (3R,3'R)-astaxanthin are rarely reported. The purpose of this study was to investigate the effect of (3R,3'R)-astaxanthin on lipid metabolism and gut microbiota in mice fed with a high-fat diet. In this work, 40 male C57BL/6 mice were divided into 8 groups fed a high-fat diet supplemented or not with (3R,3'R)-astaxanthin or Xanthophyllomyces dendrorhous for 8 weeks. The weight gain, energy intake, fat index, plasma triacylglycerol and cholesterol, liver triacylglycerol and cholesterol, and gut microbiota were determined. The results showed that the addition of (3R,3'R)-astaxanthin/X. dendrorhous to the high-fat diet as a supplement prevented weight gain, reduced plasma and liver triacylglycerol, and decreased plasma and liver total cholesterol. The addition of (3R,3'R)-astaxanthin/X. dendrorhous also regulated the gut microbiota of the mice, which optimized the ratio of Bacteroides to Firmicutes and increased the content of Verrucomicrobia, especially Akkermansia. The changes in the gut microflora achieved a healthier structure, thus reducing the incidence of obesity. Thus (3R,3'R)-Astaxanthin has the function of regulating lipid metabolism and gut microbiota to prevent obesity caused by a high-fat diet. The production strain of (3R,3'R)-astaxanthin, X. dendrorhous, has the same function as astaxanthin in preventing obesity caused by a high-fat diet, which reflects its potential ability as a probiotic drug.

Microalgae metabolites: A rich source for food and medicine

Microalgae are one of the important components in food chains of aquatic ecosystems and have been used for human consumption as food and as medicines. The wide diversity of compounds synthesized from different metabolic pathways of fresh and marine water algae provide promising sources of fatty acids, steroids, carotenoids, polysaccharides, lectins, mycosporine-like amino acids, halogenated compounds, polyketides, toxins, agar agar, alginic acid and carrageenan. This review discusses microalgae used to produce biological substances and its economic importance in food science, the pharmaceutical industry and public health.

β-carotene in Obesity Research: Technical Considerations and Current Status of the Field

Over the past decades, obesity has become a rising health problem as the accessibility to high calorie, low nutritional value food has increased. Research shows that some bioactive components in fruits and vegetables, such as carotenoids, could contribute to the prevention and treatment of obesity. Some of these carotenoids are responsible for vitamin A production, a hormone-like vitamin with pleiotropic effects in mammals. Among these effects, vitamin A is a potent regulator of adipose tissue development, and is therefore important for obesity. This review focuses on the role of the provitamin A carotenoid β-carotene in human health, emphasizing the mechanisms by which this compound and its derivatives regulate adipocyte biology. It also discusses the physiological relevance of carotenoid accumulation, the implication of the carotenoid-cleaving enzymes, and the technical difficulties and considerations researchers must take when working with these bioactive molecules. Thanks to the broad spectrum of functions carotenoids have in modern nutrition and health, it is necessary to understand their benefits regarding to metabolic diseases such as obesity in order to evaluate their applicability to the medical and pharmaceutical fields.