Improving hepatic mitochondrial biogenesis as a postulated mechanism for the antidiabetic effect of Spirulina platensis in comparison with metformin

Exploring the NRF2/HO-1 and NF-κB Pathways: Spirulina Nanoparticles as a Novel Approach to Combat Diabetic Nephropathy

Arthrospira platensis has been the subject of plentiful studies due to its purported health advantages; nevertheless, additional investigation is required to determine whether several chronic diseases may be treated or avoided with its nanoform. Therefore, we set out to examine A. platensis nanoparticles (SNPs) to protect against kidney impairment caused by Streptozotocin (STZ) in diabetic rats, precisely focusing on its effect and the cellular intracellular pathways involved. Male Wistar rats were assigned into four groups: Group 1 was set as control, comprising the normal rats; group 2 was administered SNPs (0.5 mg/kg BW, once/day) orally for 84 consecutive days; group 3, STZ-diabetic rats were injected with STZ (65 mg/kg BW); and group 4, in which the diabetic rats were treated with SNPs. After inducing diabetes in rats for 84 days, the animals were euthanized. The results disclosed that SNP treatment substantially (P < 0.05) improved the glucose and glycated hemoglobin levels (HbA1c %), insulin, C-peptide, and cystatin C deterioration in diabetic rats. Furthermore, SNP administration significantly lowered (P < 0.05) nitric oxide (NO) and malondialdehyde (MDA) levels in renal tissue and enhanced kidney function metrics, as well as improved the antioxidant capacity of the renal tissue. In addition, oral SNPs overcame the diabetic complications concerning diabetic nephropathy, indicated by downregulation and upregulation of apoptotic and antiapoptotic genes, respectively, along with prominent modulation of the antiangiogenic marker countenance level, improving kidney function. SNP modulated the nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 (NRF2/HO-1) pathways and inhibited the nuclear factor-κB (NF-κB) expression, strengthening the SNP pathways in alleviating diabetic nephropathy. The histopathology results corroborated the obtained biochemical and molecular observations, suggesting the therapeutic potential of SNPs in diabetic nephropathy via mechanisms other than its significant antioxidant and hypoglycemic effects, including modulation of antiangiogenic and inflammatory mediators and the NRF2/HO-1 pathways.

Beneficial Effects of Spirulina Supplementation in the Management of Cardiovascular Diseases

In recent decades, as a result of rising mortality rates due to cardiovascular diseases (CVDs), there has been a growing urgency to find alternative approaches to conventional pharmaceutical treatment to prevent the onset of chronic diseases. Arthrospira platensis, commonly known as Spirulina, is a blue-green cyanobacterium, classified as a "superfood", used worldwide as a nutraceutical food supplement due to its remarkable nutritional value, lack of toxicity, and therapeutic effects. Several scientific studies have evaluated the cardioprotective role of Spirulina. This article presents a comprehensive review of the therapeutic benefits of Spirulina in improving cardio- and cerebrovascular health. It focuses on the latest experimental and clinical findings to evaluate its antihypertensive, antidiabetic, and antihyperlipidemic properties. The objective is to highlight its potential in preventing and managing risk factors associated with cardiovascular disease (CVD).

Spirulina Supplementation with High-Intensity Interval Training Decreases Adipokines Levels and Cardiovascular Risk Factors in Men with Obesity

Adiposity, a state characterized by excessive accumulation of body fat, is closely linked to metabolic complications and the secretion of specific adipokines. This study explores the potential of exercise and Spirulina supplementation to mitigate these complications and modulate adipokine release associated with obesity. The primary objective of this investigation was to examine the impact of a 12-week regimen of high-intensity training combined with Spirulina supplementation on adipokine concentrations and lipid profiles in male individuals with obesity (N = 44). The participants were randomly distributed into four groups, each consisting of 11 participants: a control group (CG), a supplement group (SG), a training group (TG), and a training plus supplement group (TSG). The intervention comprised a 12-week treatment involving Spirulina supplementation (6 g capsule daily), a 12-week high-intensity interval training (HIIT) protocol with three sessions per week, or a combined approach. Following the interventions, metabolic parameters, anthropometric measurements, cardiorespiratory indices, and circulating adipokines [CRP, Sema3C, TNF-α, IL-6, MCP1, IL-8] were assessed within 48 h of the before and final training session. Statistical analyses revealed significant differences across all measures among the groups (p < 0.05). Notably, post hoc analyses indicated substantial disparities between the CG and the three interventional groups regarding body weight (p < 0.05). The combined training and supplementation approach led to noteworthy reductions in low-density lipoprotein (LDL), total cholesterol (TC), and triglyceride (TGL) levels (all p < 0.0001), coupled with an elevation in high-density lipoprotein-cholesterol (HDL-C) levels (p = 0.0001). Furthermore, adipokine levels significantly declined in the three intervention groups relative to the CG (p < 0.05). The findings from this 12-week study demonstrate that Spirulina supplementation in conjunction with high-intensity interval training reduced adipokine levels, improved body weight and BMI, and enhanced lipid profiles. This investigation underscores the potential of Spirulina supplementation and high-intensity interval training as a synergistic strategy to ameliorate obesity-related complications and enhance overall cardiometabolic well-being in obese males.

The effect of spirulina sauce on glycemic index, lipid profile, and oxidative stress in type 2 diabetic patients: A randomized double-blind clinical trial

We aimed to evaluate the effect of spirulina sauce on glycemic indices, lipid profile, oxidative stress markers, and anthropometric measurement in type 2 diabetic patients. Forty patients were randomly assigned to receive 20 g/day spirulina sauce (containing 2 g of spirulina) or placebo for 2 months. Anthropometric and biochemical indices were measured at the beginning and end of the intervention. Fasting blood glucose (mean difference (MD): -15.3 mg/dL, 95% confidence (CI): -44.2 to 13.60, p = .26), HbA1c (MD: 0.13%, 95% CI: -0.83 to 0.57, p = .75), insulin (MD: -1.46 μIU/mL, 95% CI: -4.0 to 1.09, p = .28), and HOMA-IR (MD: -0.35, 95% CI: -2.0 to 1.32, p = .68) did not change significantly between groups. QUICKI increased significantly (MD: 0.025, 95% CI: 0.006 to 0.045, p = .03). Among the lipid profile, triglyceride (TG) (MD: -68.6 mg/dL, 95% CI: -107.21 to -29.98, p < .001), total cholesterol (MD: -29.55 mg/dL, 95% CI: -55.28 to -3.81, p = .02), and LDL (MD: -17.7 mg/dL, 95% CI: -33.24 to -2.15, p = .01) were significantly decreased in the spirulina group compared to the control; whereas, the change in HDL was non-significant. No significant change was observed in body composition and anthropometric measurements, except waist circumference, which was reduced (MD: -2.65 cm, 95% CI: -3.91 to -1.38, p = .001). Hunger index significantly decreased and fullness increased marginally significantly. Although malondialdehyde was significantly reduced, no change was observed in total antioxidant capacity (TAC). Spirulina sauce was not effective for glycemic control in type 2 diabetes; however, could be useful for controlling appetite and ameliorating lipid profile.

Addition of Spirulina to Craft Beer: Evaluation of the Effects on Volatile Flavor Profile and Cytoprotective Properties

SPME-GC-MS and PTR-ToF-MS techniques were applied to describe the content of volatile flavor compounds in a craft beer before and after adding spirulina. The obtained results showed that the volatile profile of the two beer samples differed. Furthermore, to chemically characterize biomass spirulina, a derivatization reaction followed by GC-MS analysis was performed, highlighting a high content of molecules belonging to different chemical classes, such as sugars, fatty acids and carboxylic acids. A spectrophotometric analysis of total polyphenols and tannins, investigation into the scavenging activity towards DPPH and ABTS radicals and confocal microscopy of brewer's yeast cells were carried out. Moreover, the cytoprotective and antioxidant properties towards the oxidative damage induced by tert-butyl hydroperoxide (tBOOH) in human H69 cholangiocytes were investigated. Finally, the modulation of Nrf2 signaling under oxidative stress conditions was also evaluated. Both samples of beer were shown to contain similar levels of total polyphenols and tannins, with slightly increased levels in that containing spirulina 0.25% w/v. Moreover, the beers were found to be endowed with radical scavenging properties towards both DPPH and ABTS radicals, albeit with a weak contribution of spirulina; however, a higher riboflavin content was detected in spirulina-treated yeast cells. Conversely, the addition of spirulina (0.25% w/v) appeared to improve the cytoprotective properties of beer towards tBOOH-induced oxidative damage in H69 cells and reduce intracellular oxidative stress. Accordingly, the cytosolic Nrf2 expression was found to be increased.

Spirulina platensis Mitigates the Inhibition of Selected miRNAs that Promote Inflammation in HAART-Treated HepG2 Cells

The introduction of highly active antiretroviral therapy (HAART) in the treatment of HIV/AIDS has recently gained popularity. In addition, the significant role of microRNA expression in HIV pathogenesis cannot be overlooked; hence the need to explore the mechanisms of microRNA expression in the presence of HAART and Spirulina platensis (SP) in HepG2 cells. This study investigates the biochemical mechanisms of microRNA expression in HepG2 cells in the presence of HAART, SP, and the potential synergistic effect of HAART−SP. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine cell viability following SP treatment. The cellular redox status was assessed using the quantification of intracellular reactive oxygen species (ROS), lipid peroxidation, and a lactate dehydrogenase (LDH) assay. The fluorometric JC-1 assay was used to determine mitochondrial polarisation. The quantitative polymerase chain reaction (qPCR) was also employed for micro-RNA and gene expressions. The results show that MiR-146a (p < 0.0001) and miR-155 (p < 0.0001) levels increased in SP-treated cells. However, only miR-146a (p < 0.0001) in HAART−SP indicated an increase, while miR-155 (p < 0.0001) in HAART−SP treatment indicated a significant decreased expression. Further inflammation analysis revealed that Cox-1 mRNA expression was reduced in SP-treated cells (p = 0.4129). However, Cox-1 expression was significantly increased in HAART−SP-treated cells (p < 0.0001). The investigation revealed that HepG2 cells exposed to HAART−SP treatment showed a significant decrease in Cox-2 (p < 0.0001) expression. mRNA expression also decreased in SP-treated cells (p < 0.0001); therefore, SP potentially controls inflammation by regulating microRNA expressions. Moreover, the positive synergistic effect is indicated by normalised intracellular ROS levels (p < 0.0001) in the HAART−SP treatment. We hereby recommend further investigation on the synergistic roles of SP and HAART in the expression of microRNA with more focus on inflammatory and oxidative pathways.

Spirulina platensis Ameliorates Oxidative Stress Associated with Antiretroviral Drugs in HepG2 Cells

Lately, Spirulina platensis (SP), as an antioxidant, has exhibited high potency in the treatment of oxidative stress, diabetes, immune disorder, inflammatory stress, and bacterial and viral-related diseases. This study investigated the possible protective role of Spirulina platensis against ARV-induced oxidative stress in HepG2 cells. Human liver (HepG2) cells were treated with ARVs ((Lamivudine (3TC): 1.51 µg/mL, tenofovir disoproxil fumarate (TDF): 0.3 µg/mL and Emtricitabine (FTC): 1.8 µg/mL)) for 96 h and thereafter treated with 1.5 µg/mL Spirulina platensis for 24 h. After the treatments, the gene and protein expressions of the antioxidant response pathway were determined using a quantitative polymerase chain reaction (qPCR) and Western blots. The results show that Spirulina platensis decreased the gene expressions of Akt (p < 0.0001) and eNOS (↓p < 0.0001) while, on the contrary, it increased the transcript levels of NRF-2 (↑p = 0.0021), Keap1 (↑p = 0.0002), CAT (↑p < 0.0001), and NQO-1 (↑p = 0.1432) in the HepG2 cells. Furthermore, the results show that Spirulina platensis also decreased the protein expressions of NRF-2 (↓p = 0.1226) and pNRF-2 (↓p = 0.0203). Interestingly, HAART-SP induced an NRF-2 pathway response through upregulating NRF-2 (except for FTC-SP) (↑p < 0.0001), CAT (↑p < 0.0001), and NQO-1 (except for FTC-SP) (↑p < 0.0001) mRNA expression. In addition, NRF-2 (↑p = 0.0085) and pNRF-2 (↑p < 0.0001) protein expression was upregulated in the HepG2 cells post-exposure to HAART-SP. The results, therefore, allude to the fact that Spirulina platensis has the potential to mitigate HAART-adverse drug reactions (HAART toxicity) through the activation of antioxidant response in HepG2 cells. We hereby recommend further studies on Spirulina platensis and HAART synergy.

Research Progresses on the Physiological and Pharmacological Benefits of Microalgae-Derived Biomolecules

Microalgae are a kind of photoautotrophic microorganism, which are small, fast in their growth rate, and widely distributed in seawater and freshwater. They have strong adaptability to diverse environmental conditions and contain various nutrients. Many scholars have suggested that microalgae can be considered as a new food source, which should be developed extensively. More importantly, in addition to containing nutrients, microalgae are able to produce a great number of active compounds such as long-chain unsaturated fatty acids, pigments, alkaloids, astaxanthin, fucoidan, etc. Many of these compounds have been proven to possess very important physiological functions such as anti-oxidation, anti-inflammation, anti-tumor functions, regulation of the metabolism, etc. This article aimed to review the physiological functions and benefits of the main microalgae-derived bioactive molecules with their physiological effects.

The Potential of Spirulina platensis to Ameliorate the Adverse Effects of Highly Active Antiretroviral Therapy (HAART)

The human immunodeficiency virus (HIV) is one of the most prevalent diseases globally. It is estimated that 37.7 million people are infected with HIV globally, and 8.2 million persons are infected with the virus in South Africa. The highly active antiretroviral therapy (HAART) involves combining various types of antiretroviral drugs that are dependent on the infected person’s viral load. HAART helps regulate the viral load and prevents its associated symptoms from progressing into acquired immune deficiency syndrome (AIDS). Despite its success in prolonging HIV-infected patients’ lifespans, the use of HAART promotes metabolic syndrome (MetS) through an inflammatory pathway, excess production of reactive oxygen species (ROS), and mitochondrial dysfunction. Interestingly, Spirulina platensis (SP), a blue-green microalgae commonly used as a traditional food by Mexican and African people, has been demonstrated to mitigate MetS by regulating oxidative and inflammatory pathways. SP is also a potent antioxidant that has been shown to exhibit immunological, anticancer, anti-inflammatory, anti-aging, antidiabetic, antibacterial, and antiviral properties. This review is aimed at highlighting the biochemical mechanism of SP with a focus on studies linking SP to the inhibition of HIV, inflammation, and oxidative stress. Further, we propose SP as a potential supplement for HIV-infected persons on lifelong HAART.

The diabetogenic effects of chronic supplementation of vitamin C or E in rats: Interplay between liver and adipose tissues transcriptional machinery of lipid metabolism

AIM

The chronic administration of vitamin C and E can differentially disrupt hepatic insulin molecular pathway in rats. Hence, this study evaluated their effects on lipogenesis in the liver and adipose tissue and investigated the possible involvement of microRNA (miR)-22/29a/27a in the induced impaired glucose tolerance.

MAIN METHODS

Wistar rats were orally supplemented with vitamin C (100, 200, and 500 mg/kg) or vitamin E (50, 100, and 200 mg/kg) for eight months.

KEY FINDINGS

Vitamin C or E at the highest doses significantly altered liver weight and index, serum and hepatic lipids, adiponectin, and liver enzymes; besides their reported unfavorable effect on glucose homeostasis. Vitamin C and E negatively affected peroxisome proliferator-activated receptor coactivator-1 (PGC-1α), sterol regulatory element-binding protein (SREBP)-1c/-2, miR-22/29a/27a expression, and adipose perilipin 1 to different extents, effects that were supported by the histopathological examination.

SIGNIFICANCE

The current study provides a deeper insight into the findings of our previous study and highlights the detrimental effects of chronic vitamins supplementation on lipid metabolism. Overall, these findings emphasize the damage caused by the mindless use of supplements and reinforce the role of strict medical monitoring, particularly during the new COVID-19 era during which numerous commercial supplements are claiming to improve immunity.

High-intensity interval training along with spirulina algae consumption and caloric restriction ameliorated the Nrf1/Tfam/Mgmt and ATP5A1 pathway in the heart tissue of obese rats

Nrf1/Tfam/MGMT and ATP5A1 might be a pivotal network in cardiovascular disease-inducing obesity. Therefore, we evaluated eight weeks of exercise, caloric restriction, and spirulina algae consumption on the heart in obese rats. In this study, obese rats were compared with a healthy group. First, we induced obese rats with a 60%-high-fat diet. Then, after eight weeks, obese rats were randomly divided into eight groups: obese rats without treatment (HFD), obese rats treated with spirulina algae (HFD-SA), obese rats conducted exercise (HFD-EX), obese rats treated with spirulina algae and exercise (HFD-SA+EX), obese rats treated with caloric restriction (HFD-CR), obese rats treated with caloric restriction and exercise (HFD-CR+EX), obese rats treated with spirulina algae and caloric restriction (HFD-SA+CR), and obese rats treated with SA+CR+EX (HFD-SA+CR+EX). Also, the exercise protocol was performed for eight weeks, three sessions per week at an intensity of 80%-110% of maximum running speed. The spirulina algae were consumed by gavage (100 mg/kg/day), and caloric restriction used 60% of the food consumed. We found that SA+CR+EX significantly modified the Nrf1/Tfam/MGMT and ATP5A1 network in cardiovascular disease-inducing obesity rats (p < .01). Moreover, we predicted SA could be bound to Tfam and MGMT protein targets. Hence, exercise, caloric restriction, and spirulina algae had a synergistic effect on mitochondrial biogenesis in the heart tissue of obese rats (p < .01). PRACTICAL APPLICATIONS: According to artificial intelligence and medical biology servers, we discovered that mitochondrial biogenesis and oxidative stress are dominant phenomena in the cardiovascular system. Nrf1/Tfam/MGMT and ATP5A1, as pivotal regulators of oxidative stress, could play an utmost important role in the cardiovascular disease-inducing obesity molecular pathway. Furthermore, several studies have indicated that environmental factors such as the western diet and physical inactivity disrupted the mitochondrial dynamic, which led to increased reactive oxygen species (ROS). We predicted the binding power of the Spirulina's small molecules on Tfam and Mgmt proteins based on drug-discovery technology and pharmacokinetic parameters. Considering oxidative stress and mitochondrial machinery related to the action of some molecular pathways, mitochondria-related nuclear-encoded proteins, and ROS, this study evaluated the high-intensity interval training, caloric restriction, and spirulina consumption on heart mitochondrial biogenesis in obese rats. Our data might provide a novel strategy for the prevention and treatment of cardiovascular disease-inducing obesity.

From Farm to Fingers: an Exploration of Probiotics for Oysters, from Production to Human Consumption

Oysters hold a unique place within the field of aquaculture as one of the only organisms that is regularly shipped live to be consumed whole and raw. The microbiota of oysters is capable of adapting to a wide range of environmental conditions within their dynamic estuarine environments; however, human aquaculture practices can challenge the resilience of this microbial community. Several discrete stages in oyster cultivation and market processing can cause disruption to the oyster microbiota, thus increasing the possibility of proliferation by pathogens and spoilage bacteria. These same pressure points offer the opportunity for the application of probiotics to help decrease disease occurrence in stocks, improve product yields, minimize the risk of shellfish poisoning, and increase product shelf life. This review provides a summary of the current knowledge on oyster microbiota, the impact of aquaculture upon this community, and the current status of oyster probiotic development. In response to this biotechnological gap, the authors highlight opportunities of highest potential impact within the aquaculture pipeline and propose a strategy for oyster-specific probiotic candidate development.

Ameliorative effects of garlic oil on FNDC5 and irisin sensitivity in liver of streptozotocin-induced diabetic rats

OBJECTIVES

This study was aimed to investigate the effects of garlic oil (GO), an important natural constituent used in alleviating diabetes and its complications, on the expression levels of irisin and related genes.

METHODS

Thirty-two rats were divided into four groups: Control, Diabetes-Control, Diabetes+GO 100 mg/kg/day and Control+GO 100 mg/kg/day for 45 days. The measurements included: changes in liver Peroxisome proliferator-activated receptor-gamma-coactivator (PGC)-1α, Fibronectin Type-III-Domain-Containing5 (FNDC5), irisin expression, mRNA expression of p38 and TNF-α (Tumour necrosis factor-α), total-antioxidant-status (L-TAS; S-TAS), total-oxidant-status (L-TOS; S-TOS) in liver and serum, respectively.

KEY FINDINGS

There was a significant reduction in serum levels of irisin and S-TAS and expression of PGC-1α and FNDC5 in liver in Diabetes-control compared to Control-group, while a significant increase in serum levels of fasting blood glucose (FBG) and TOS, also p38 and TNF-α expressions in liver. In Diabetes+GO group, there was a significant increase in serum irisin and S-TAS, also expression of PGC-1α and FNDC5 in liver, while serum FBG, S-TOS levels, and mRNA expression of p38 and TNF-α in liver were decreased compared to Diabetes-control group (P < 0.05).

CONCLUSIONS

GO alleviated the diabetic liver injury by decreasing Oxidative-Stress parameters and regulation PGC-lα, FNDC5, irisin and P38, keeping the balance of TAS/TOS and TNF-α.

Edible Microalgae and Their Bioactive Compounds in the Prevention and Treatment of Metabolic Alterations

Marine and freshwater algae and their products are in growing demand worldwide because of their nutritional and functional properties. Microalgae (unicellular algae) will constitute one of the major foods of the future for nutritional and environmental reasons. They are sources of high-quality protein and bioactive molecules with potential application in the modern epidemics of obesity and diabetes. They may also contribute decisively to sustainability through carbon dioxide fixation and minimization of agricultural land use. This paper reviews current knowledge of the effects of consuming edible microalgae on the metabolic alterations known as metabolic syndrome (MS). These microalgae include Chlorella, Spirulina (Arthrospira) and Tetraselmis as well as Isochrysis and Nannochloropsis as candidates for human consumption. Chlorella biomass has shown antioxidant, antidiabetic, immunomodulatory, antihypertensive, and antihyperlipidemic effects in humans and other mammals. The components of microalgae reviewed suggest that they may be effective against MS at two levels: in the early stages, to work against the development of insulin resistance (IR), and later, when pancreatic -cell function is already compromised. The active components at both stages are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and -3 PUFAs (eicosapentaenoic acid/docosahexaenoic acid; EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins, such as folate. As a source of high-quality protein, including an array of bioactive molecules with potential activity against the modern epidemics of obesity and diabetes, microalgae are proposed as excellent foods for the future. Moreover, their incorporation into the human diet would decisively contribute to a more sustainable world because of their roles in carbon dioxide fixation and reducing the use of land for agricultural purposes.

Valsartan solid lipid nanoparticles integrated hydrogel: A challenging repurposed use in the treatment of diabetic foot ulcer, in-vitro/in-vivo experimental study

The article presents an experimental study on the possible repurposed use of valsartan (Val), in the local treatment of uncontrolled diabetic foot ulcer. Solid lipid nanoparticles (SLN), loaded with Val were prepared by applying 3² full factorial design using modified high shear homogenization method. The lipid phase composed of Precirol® ATO 5 (P ATO 5) and/or Gelucire 50/13 (G 50/13) in different ratios and a nonionic emulsifier, Pluronic 188 (P188), was used in different percentages. Optimized formulation was further integrated in hydroxyl propyl methyl cellulose (HPMC) gel for the ease of administration. In-vitro and in-vivo characterizations were investigated. The prepared nanoparticles showed small particle size, high entrapment efficiency and sustained drug release. Microbiologically, Val-SLN showed a prominent decrease in the biofilm mass formation for both gram-positive and gram-negative bacteria, as well as a comparable minimum inhibitory concentration level to levofloxacin alone. Diabetes was induced in 32 neonatal Sprague-Dawley rats. At 8 weeks of age, rats with blood sugar level >160 were subjected to surgically induced ulcer. Treatment with Val-SLN for 12 days revealed enhanced healing characteristics through cyclooxygenase-2 (COX-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nitric oxide (NO), transforming growth factor-beta (TGF-β), matrix metalloproteinase (MMPs) and vascular endothelial growth factor (VEGF) pathways. Histological examination revealed re-epithelization in Val-SLN treated ulcer, as well as decrease in collagen using trichrome histomorphometric analysis.

Effects of Spirulina platensis on insulin secretion, dipeptidyl peptidase IV activity and both carbohydrate digestion and absorption indicate potential as an adjunctive therapy for diabetes

Spirulina platensis has been found to be useful in the treatment of type 2 diabetes. The present study aims to elucidate the effects of ethanol extract and butanol fraction of S. platensis on insulin release and glucose homoeostasis in type 2 diabetic rats, together with their mechanism of actions. In vitro and in vivo methods were used including cellular studies to determine potential role of ion channels and cAMP in the insulinotropic actions of the extracts. The ethanol extract and butanol fraction stimulated insulin release from mouse islets and pancreatic β-cells in a concentration-dependent manner. The butanol fraction also similarly stimulated insulin release from perfused rat pancreas. The insulin-releasing action was augmented by glucose, isobutylmethylxanthine, tolbutamide and a depolarising concentration of KCl. The insulin secretory effect was attenuated with diazoxide and verapamil and by omission of extracellular Ca2+. Butanol fraction was found to significantly inhibit dipeptidyl peptidase IV enzyme activity. Moreover, butanol fraction improved glucose tolerance following oral glucose administration (2·5 g/kg body weight (b.w.)). The butanol fraction was tested on 24 h starved rats given an oral sucrose load (2·5 g/kg b.w.) to examine possible effects on carbohydrate digestion and absorption. S. platensis substantially decreased postprandial hyperglycaemia after oral sucrose load and increased unabsorbed sucrose content throughout the gut. During in situ intestinal perfusion with glucose, the butanol fraction reduced glucose absorption and promoted gut motility. Finally, chronic oral administration of butanol fraction for 28 d significantly decreased blood glucose, increased plasma insulin, pancreatic insulin stores, liver glycogen and improved lipid profile. The characterisation of active compounds from butanol fraction revealed the presence of p-coumaric acid, β-carotene, catechin and other antioxidant polyphenols. In conclusion, S. platensis could be an adjunctive therapy for the management of type 2 diabetes.

Spirulina for the food and functional food industries

Humans are no strangers to the consumption of microalgae as already in the sixteenth century Spirulina was harvested from Lake Texcoco and consumed in markets in Tenochtitlan (today Mexico City). Nowadays, microalgae are being incorporated into many food formulations. Most of these use microalgae as a marketing strategy or as a colouring agent. However, Spirulina (and compounds derived thereof) show potential for being used as ingredients in the development of novel functional foods, which are one of the top trends in the food industry. Several human intervention studies demonstrated the potential of Spirulina for being used in the prevention or treatment of disorders related to metabolic syndrome. The aim of the current paper was to review current and potential applications of this microalga in the food and functional food industries. Health benefits associated with consuming Spirulina and/or some of the most important compounds derived from Spirulina were also discussed.

Neonatal diet impacts liver mitochondrial bioenergetics in piglets fed formula or human milk

BACKGROUND

Neonatal diet impacts many physiological systems and can modify risk for developing metabolic disease and obesity later in life. Less well studied is the effect of postnatal diet (e.g., comparing human milk (HM) or milk formula (MF) feeding) on mitochondrial bioenergetics. Such effects may be most profound in splanchnic tissues that would have early exposure to diet-associated or gut microbe-derived factors.

METHODS

To address this question, we measured ileal and liver mitochondrial bioenergetics phenotypes in male piglets fed with HM or MF from day 2 to day 21 age. Ileal and liver tissue were processed for mitochondrial respiration (substrate only [pyruvate, malate, glutamate], substrate + ADP, and proton "leak" post-oligomycin; measured by Oroboros methods), mitochondrial DNA (mtDNA) and metabolically-relevant gene expression analyses.

RESULTS

No differences between the diet groups were observed in mitochondrial bioenergetics indices in ileal tissue. In contrast, ADP-dependent liver Complex I-linked OXPHOS capacity and Complex I + II-linked OXPHOS capacity were significantly higher in MF animals relative to HM fed piglets. Interestingly, p53, Trap1, and Pparβ transcript abundances were higher in MF-fed relative to HM-fed piglets in the liver. Mitochondrial DNA copy numbers (normalized to nuclear DNA) were similar within-tissue regardless of postnatal diet, and were ~ 2-3 times higher in liver vs. ileal tissue.

CONCLUSION

While mechanisms remain to be identified, the data indicate that neonatal diet can significantly impact liver mitochondrial bioenergetics phenotypes, even in the absence of a change in mtDNA abundance. Since permeabilized liver mitochondrial respiration was increased in MF piglets only in the presence of ADP, it suggests that formula feeding led to a higher ATP turnover. Specific mechanisms and signals involved with neonatal diet-associated differences in liver bioenergetics remain to be elucidated.

Modulation of the hepatic expression of miR-33 and miR-34a possibly mediates the metabolic effects of estrogen in ovariectomized female rats

Estrogen and the estrogen receptors (ERs) are well-known regulators of several aspects of glucose and lipid metabolism. Meanwhile, the underlying mechanistic role of estrogens in regulating metabolic health remains largely unknown. Hence, the study was designed to tackle the possible contribution of the hepatic expression of miR-33, miR-21 and miR-34a and their target genes as the underlying mechanism of the metabolic effects of estrogen in ovariectomized rats. Forty female rats were ovariectomized (OVX), treated with estrogen and/or fulvestrant for 28 days and compared with untreated or treated sham operated rats. Estradiol amended the metabolic abnormalities in the OVX rats, witnessed by decreasing blood sugar, insulin and HOMA-IR as well as correcting the disrupted serum and hepatic lipids. Estradiol increased the hepatic expression of miR-33 and inhibited that of miR-34a and miR-21, leading to adjusting the gene expression and the protein level of their targets, sterol regulatory element-binding proteins-1c (SREBP-1c), fatty acid synthase (FASN), high mobility group (HMG) Box Transcription Factor 1 (HBP1) and Sirtuin 1 (SIRT1), receptively. However, estrogen had no significant effects on HBP1 protein. These effects were almost completely inhibited by fulvestrant, an estrogen receptor blocker, to the extent that fulvestrant had similar metabolic disorders to that of ovariectomization. In conclusion, estrogen replacement therapy in OVX females significantly ameliorated the metabolic derangements of insulin resistance, dyslipidemia and hepatic fat accumulation possibly via corrections of hepatic expression of miR-33 and miR-34a; effects that were mediated through the receptor-mediated signaling of ERs as confirmed by fulvestrant.

Mitochondrial biogenesis: An update

In response to the energy demand triggered by developmental signals and environmental stressors, the cells launch the mitochondrial biogenesis process. This is a self‐renewal route, by which new mitochondria are generated from the ones already existing. Recently, considerable progress has been made in deciphering mitochondrial biogenesis‐related proteins and genes that function in health and in pathology‐related circumstances. However, an outlook on the intracellular mechanisms shared by the main players that drive mitochondrial biogenesis machinery is still missing. Here, we provide such a view by focusing on the following issues: (a) the role of mitochondrial biogenesis in homeostasis of the mitochondrial mass and function, (b) the signalling pathways beyond the induction/promotion, stimulation and inhibition of mitochondrial biogenesis and (c) the therapeutic applications aiming the repair and regeneration of defective mitochondrial biogenesis (in ageing, metabolic diseases, neurodegeneration and cancer). The review is concluded by the perspectives of mitochondrial medicine and research.

Metformin as a protective agent against natural or chemical toxicities: a comprehensive review on drug repositioning

BACKGROUND

Metformin is the first prescribed drug for hyperglycemia in type 2 diabetes mellitus. Mainly by activating AMPK pathway, this drug exerts various functions that among them protective effects are of the interest.

PURPOSE

Herein, we aimed to gather data about the protective impacts of metformin against various natural or chemical toxicities.

RESULTS

An extensive search among PubMed, Scopus, and Google Scholar was conducted by keywords related to protection, toxicity, natural and chemical toxins and, metformin. Our literature review showed metformin alongside its anti-hyperglycemic effect has a wide range of anti-toxic effects against anti-tumour and routine drugs, natural and chemical toxins, herbicides and, heavy metals.

CONCLUSION

It is evident that metformin is a potent drug against the toxicity of a broad spectrum of natural, chemical toxic agents which is proved by a vast number of studies. Metformin mainly through AMPK axis can protect different organs against toxicities. Moreover, metformin preserves DNA integrity and can be an option for adjuvant therapy to ameliorate side effect of other therapeutics.

Effect of folate supplementation on immunological and autophagy markers in experimental nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Chronic hepatic inflammation is an important pathogenic mediator of nonalcoholic fatty liver disease (NAFLD) that contributes to disease severity. It is commonly suggested that autophagy dysfunction may be an underlying cause of nonalcoholic fatty liver disease. However, the exact role of autophagy in lipid metabolism remains controversial. There has been a growing interest in the role of folate supplementation for the treatment and/or prevention of NAFLD. We aimed in this study to investigate the effects of different doses of folate supplementation on several immune markers and autophagy trying to explore the complex role of IL-22 and autophagy in NAFLD.

METHODS

Fifty Wistar rats were randomly separated into experimental (n = 40) and control groups (n = 10), which were fed for eight weeks with a high-fat diet (HFD) containing 40% fats or a standard diet, respectively. The experimental group was further subdivided into four subgroups where the first subgroup was left untreated while the other three were treated with different doses of folate (50, 100, and 150 μg/kg of body weight, respectively). At the end of the experimental period, animals from each group were sacrificed for blood and tissue analyses.

RESULTS

NAFLD rats showed decreased IL-22 serum levels and increased LC3B expression as compared to controls. Folate treatment was significantly associated with improvement in disease parameters, reduced presence of the pro-inflammatory cytokines TNF-α and CXCL8 and LC3B expression, and increased IL-22 levels in a dose-dependent manner.

CONCLUSION

These results highlight the capacity of folate to modulate the production of several pro-inflammatory cytokines and autophagy thereby having a favorable impact disease progression.