Activation of the human innate immune system by Spirulina: augmentation of interferon production and NK cytotoxicity by oral administration of hot water extract of Spirulina platensis

Effect of Spirulina Nigrita® Supplementation on Indices of Exercise-Induced Muscle Damage after Eccentric Protocol of Upper Limbs in Apparently Healthy Volunteers

Spirulina is a supplement with antioxidant and anti-inflammatory properties that may enhance performance and recovery after intense exercise. The present study aimed to investigate the effects of Spirulina Nigrita® on physical performance, and recovery markers after intense eccentric exercise in healthy moderately physically active volunteers. In a double-blind crossover design, participants were supplemented either with spirulina (42 mg Kg-1 BW per day) or a placebo for 15 days before conducting an eccentric exercise protocol using the non-dominant arm. A six-week washout period was required between conditions. Performance and mobility markers such as isometric peak torque (PTQ), ligament range of motion (ROM), and perceived muscle discomfort (VAS) were assessed and blood samples (CK, LDH) were obtained at 1, 24, 48, and 72 h post-exercise. No significant differences were noticed between the two conditions on any of the investigated markers, indicating that spirulina supplementation has no positive effect on isometric muscle performance or alleviation of exercise-induced muscle damage (EIMD) symptoms in the specific population.

Antimicrobial Activity of Arthrospira (Former Spirulina) and Dunaliella Related to Recognized Antimicrobial Bioactive Compounds

With the increasing rate of the antimicrobial resistance phenomenon, natural products gain our attention as potential drug candidates. Apart from being used as nutraceuticals and for biotechnological purposes, microalgae and phytoplankton have well-recognized antimicrobial compounds and proved anti-infectious potential. In this review, we comprehensively outline the antimicrobial activity of one genus of cyanobacteria (Arthrospira, formerly Spirulina) and of eukaryotic microalgae (Dunaliella). Both, especially Arthrospira, are mostly used as nutraceuticals and as a source of antioxidants for health supplements, cancer therapy and cosmetics. Their diverse bioactive compounds provide other bioactivities and potential for various medical applications. Their antibacterial and antifungal activity vary in a broad range and are strain specific. There are strains of Arthrospira platensis with very potent activity and minimum inhibitory concentrations (MICs) as low as 2-15 µg/mL against bacterial fish pathogens including Bacillus and Vibrio spp. Arthrospira sp. has demonstrated an inhibition zone (IZ) of 50 mm against Staphylococcus aureus. Remarkable is the substantial amount of in vivo studies of Arthrospira showing it to be very promising for preventing vibriosis in shrimp and Helicobacter pylori infection and for wound healing. The innovative laser irradiation of the chlorophyll it releases can cause photodynamic destruction of bacteria. Dunaliella salina has exhibited MIC values lower than 300 µg/mL and an IZ value of 25.4 mm on different bacteria, while Dunaliella tertiolecta has demonstrated MIC values of 25 and 50 μg/mL against some Staphylococcus spp. These values fulfill the criteria for significant antimicrobial activity and sometimes are comparable or exceed the activity of the control antibiotics. The bioactive compounds which are responsible for that action are fatty acids including PUFAs, polysaccharides, glycosides, peptides, neophytadiene, etc. Cyanobacteria, such as Arthrospira, also particularly have antimicrobial flavonoids, terpenes, alkaloids, saponins, quinones and some unique-to-them compounds, such as phycobiliproteins, polyhydroxybutyrate, the peptide microcystin, etc. These metabolites can be optimized by using stress factors in a two-step process of fermentation in closed photobioreactors (PBRs).

Effect of high-dose Spirulina supplementation on hospitalized adults with COVID-19: a randomized controlled trial

Objective

Spirulina (arthrospira platensis) is a cyanobacterium proven to have anti-inflammatory, antiviral, and antioxidant effects. However, the effect of high-dose Spirulina supplementation on hospitalized adults with COVID-19 is currently unclear. This study aimed to evaluate the efficacy and safety of high-dose Spirulina platensis for SARS-CoV-2 infection.

Study Design

We conducted a randomized, controlled, open-label trial involving 189 patients with COVID-19 who were randomly assigned in a 1:1 ratio to an experimental group that received 15.2g of Spirulina supplement plus standard treatment (44 non-intensive care unit (non-ICU) and 47 ICU), or to a control group that received standard treatment alone (46 non-ICU and 52 ICU). The study was conducted over six days. Immune mediators were monitored on days 1, 3, 5, and 7. The primary outcome of this study was mortality or hospital discharge within seven days, while the overall discharge or mortality was considered the secondary outcome.

Results

Within seven days, there were no deaths in the Spirulina group, while 15 deaths (15.3%) occurred in the control group. Moreover, within seven days, there was a greater number of patients discharged in the Spirulina group (97.7%) in non-ICU compared to the control group (39.1%) (HR, 6.52; 95% CI, 3.50 to 12.17). Overall mortality was higher in the control group (8.7% non-ICU, 28.8% ICU) compared to the Spirulina group (non-ICU HR, 0.13; 95% CI, 0.02 to 0.97; ICU, HR, 0.16; 95% CI, 0.05 to 0.48). In non-ICU, patients who received Spirulina showed a significant reduction in the levels of IL-6, TNF-α, IL-10, and IP-10 as intervention time increased. Furthermore, in ICU, patients who received Spirulina showed a significant decrease in the levels of MIP-1α and IL-6. IFN-γ levels were significantly higher in the intervention group in both ICU and non-ICU subgroups as intervention time increased. No side effects related to Spirulina supplements were observed during the trial.

Conclusion

High-dose Spirulina supplements coupled with the standard treatment of COVID-19 may improve recovery and remarkably reduce mortality in hospitalized patients with COVID-19.

Clinical Trial Registration

https://irct.ir/trial/54375, Iranian Registry of Clinical Trials number (IRCT20210216050373N1).

Spirulina (Arthrospira platensis): Antiallergic Agent or Hidden Allergen? A Literature Review

Presently, there has been an increase in the consumption of the blue-green microalga-spirulina (Arthrospira species), which dominates 99.5% of the total world production of microalgae. Primarily sold as a dietary supplement, it is also incorporated into snacks, pasta, cookies, and bread. Owing to its nutrient abundance, spirulina has a variety of potential applications. Extensive studies have been conducted on the health benefits of spirulina, but its safety in terms of allergy has received limited attention. Therefore, to bridge this knowledge deficit, this review aimed to evaluate the allergenic and antiallergic potential of spirulina. In the PubMed and Scopus databases using words related to allergy, we attempted to detect papers on hypersensitivity to spirulina. A total of 128 records were identified, of which 49 were screened. Ultimately, in this review, we analyzed four case studies, encompassing a total of five patients with allergies to spirulina. We assessed the severity of allergic reactions following World Allergy Organization (WAO) Anaphylaxis Guidance 2020, which varied from mild (grade 2) to severe (grade 4) based on the patient's symptoms. Additionally, our findings indicate that allergy to spirulina is not commonly reported or diagnosed. However, most of the described cases (four of five) regarding allergy to spirulina according to WAO Anaphylaxis Guidance 2020 were classified as anaphylaxis. Furthermore, it is noteworthy that spirulina also possesses antiallergic properties, as evidenced by research studies. Our article delves into both the allergic and antiallergic potential of spirulina.

Polysaccharides derived from Spirulina platensis inhibited Singapore grouper iridovirus by impeding the entry of viral particles

Attributable to the rapid dissemination and high lethality of Singapore grouper iridovirus (SGIV), it has caused significant economic losses for marine fish aquaculture in China and Southeast Asian nations. Hence, there is an urgent need to find antiviral drugs that are both safe and effective. In this study, a novel heteropolysaccharide named Spirulina platensis polysaccharides (SPP) was purified and characterized from S. platensis. The molecular weight of SPP is 276 kDa and it mainly consists of Glc and Rha, followed by minor components such as Gal, Xyl, and Fuc. The backbone of SPP was determined to be →2) -β-Rhap-(1 → 4) -α-Fucp-(1 → [2) -α-Rhap-(1] 2[→6)-α-Glcp-(1] 4[→ 4) -α-Glcp-(1] 8[→ 4) -β-Glcp-(1]2→, with branches of β-Galp, α-Xylp and α-Glcp. SPP significantly inhibited SGIV-induced cytopathic effects (CPEs), viral gene replication and viral protein expression. The antiviral mechanism of SPP was associated with the disruption of SGIV entry to host cells. Furthermore, it was not observed that SPP made statistically significant impact on the expression of interferon-related cytokines. Our results offered novel insights into the potential utilization of spirulina polysaccharides for combating aquatic animal viruses.

The influence of Spirulina extract on pathogenicity, immune response, and vaccine efficacy against H9N2 avian influenza virus in specific pathogen free chickens

Avian influenza (AI) viruses pose a risk to the worldwide poultry industry. Ultimately, improving the efficiency of the H9N2 vaccine is necessary to better control low-pathogenic avian influenza-H9N2 by using natural immunostimulant. Therefore, the goal of the present study was to examine varying doses of the cyanobacterium Spirulina extract on the effectiveness of H9N2 vaccine. Thus, a total of 150 specific pathogen-free (SPF) chickens were allocated into 6 groups, 25 birds each, as follow: G1, G2, and G6 were supplemented with 200, 400, and 400 mg Spirulina extract/kg feed, respectively, whilst the feed in G3, G4, and G5 were not supplemented with Spirulina extract. At 21-days-old, only the chickens in G1, G2, and G3 were vaccinated with the H9N2 AI vaccine. After 4 wk postvaccination, the chickens in G1, G2, G3, G4, and G6 were challenged with H9N2 AI Egyptian strain. The challenged virus was selected from a recent circulating Egyptian strain during 2022, and it was related to A/quail/Hong Kong/G1/97-like virus lineage and clustered with G1-B sub-lineage EGY-2 group. It had a high amino acids identity percentage of 92.6% with the A/chicken/Iran/av1221/1998 (Boehringer Ingelheim) vaccine. The results of real-time reverse-transcriptase polymerase-chain-reaction (rRT-PCR) revealed that no shedding of the virus was reported in G1, G2, G3, and G5. The supplementation of Spirulina extract in low (200 mg/kg of feed) and high (400 mg/kg of feed) concentration with the birds vaccinated with H9N2 AI vaccine (G1 and G2) induced prominent immuno-stimulatory effect in a dose dependent manner where it strongly enhanced the phagocytic activities of broilers' peripheral blood monocytes, and lysozyme at all days postvaccination (dpv) and days postchallenge (dpc) compared to other groups with significant differences at all day of experiment and 21st dpv, 28th dpv, 7th dpc, and 14th dpc, respectively. The supplementation with Spirulina extract in G1 and G2 induced the highest hemagglutination inhibition antibody titer in a dose-dependent manner at all-time intervals. The antibody titer postvaccination was significantly increased in G1 and G2 at 14th, and 21st dpv, in comparison with G3. Furthermore, G1 and G2 showed higher significant antibody titers at 7th and 14th dpc, compared to other groups. Furthermore, Spirulina extract (200 and 400 mg/kg feed) in G1 and G2 showed anti-inflammatory effect in a dose dependant manner by downregulating nitric oxide levels at all times postchallenge with a significant difference at 3 to 7 dpc compared to G3, G4, and G6, with improved histopathological alterations in the trachea, lung, kidney, spleen, and bursa of Fabricius.  G6 supplied with 400 mg/kg Spirulina extract feed only without vaccination had a similar effect as vaccinated groups on innate immunity. However, it delayed the production of antibodies and did not prevent viral shedding as in vaccinated groups. In conclusion, vaccination in conjunction with either dose of Spirulina extract (G1, and G2) prevents viral shedding, increases the immune response, and reduces inflammation and histopathological change caused by H9N2 AI infection in a dose dependent manner. We recommend the use of 400 mg Spirulina extract/kg feed as a natural immunostimulant in conjunction with the H9N2 vaccine to achieve the highest possible level of protection against H9N2 AI infection.

Immulina as an Immunostimulatory Supplement: Formulation and Pharmacological Studies

Immulina is a commercially available extract of Arthrospira platensis enriched with bacterial lipoproteins that acts as a potent Toll-like receptor 2 agonist. However, the immunostimulatory effect of Immulina is not well understood in vivo. Here, to devise an Immulina formulation suitable for in vivo oral gavage dosing, Immulina nanosuspension was prepared and freeze-dried to yield lyophilized nano-Immulina, which had an average particle size of around 300 nm and fully retained the bioactivity as a Toll-like receptor 2 agonist. Compared to the regular Immulina powder, lyophilized nano-Immulina notably accelerated the dissolution in aqueous media. Immulina nanosuspension was found to stimulate the production of proinflammatory cytokines in murine bone marrow-derived dendritic cells and macrophages. The immune response to Immulina was investigated in healthy mice by longitudinally monitoring the phagocytic activity of circulating neutrophils as a surrogate marker. Following daily oral ingestion of Immulina nanosuspension (10 mg/mouse/day), the phagocytic activity of circulating neutrophils was significantly elevated, suggesting an important mechanism for Immulina to enhance innate immunity.

Herbal supplement Spirulina stimulates inflammatory cytokine production in patients with dermatomyositis in vitro

Spirulina, an herbal supplement and popular ingredient in health foods, is a potent stimulant of the immune system. Spirulina use is temporally associated with the onset or exacerbation of Dermatomyositis (DM), an autoimmune connective tissue disease that frequently affects the skin and muscle. In this study, we investigated the effect of Spirulina on peripheral blood mononuclear cells (PBMCs) in DM and Healthy Controls (HCs), showing that Spirulina stimulates Interferon β (IFNβ), Tumor necrosis factor α (TNFα), and Interferon γ (IFNγ) production of DM PBMCs primarily via Toll-Like Receptor 4 (TLR4) activation using ELISA (enzyme linked immunosorbent assay) and flow cytometry. We show that classical monocytes and monocyte-derived dendritic cells are stimulated by Spirulina and are activated via TLR4. Skin from patients with Spirulina-associated DM exhibits an inflammatory milieu similar to that of idiopathic DM but with a stronger correlation of TLR4 and IFNγ.

Restoration of mitochondrial function by Spirulina polysaccharide via upregulated SOD2 in aging fibroblasts

Reactive oxygen species (ROS), such as superoxide, are crucial factors involved in the stimulation of cellular aging. Mitochondria, which are important organelles responsible for various metabolic processes in cells, produce ROS. These ROS impair mitochondrial function, thereby accelerating aging-related cellular dysfunction. Herein, we demonstrated that the Spirulina polysaccharide complex (SPC) restores mitochondrial function and collagen production by scavenging superoxide via the upregulation of superoxide dismutase 2 (SOD2) in aging fibroblasts. We observed that SOD2 expression was linked to inflammatory pathways; however, SPC did not upregulate the expression of most inflammatory cytokines produced as a result of induction of LPS in aging fibroblasts, indicating that SPC induces SOD2 without activation of inflammatory pathways. Furthermore, SPC stimulated endoplasmic reticulum (ER) protein folding by upregulating ER chaperones expression. Thus, SPC is proposed to be an antiaging material that rejuvenates aging fibroblasts by increasing their antioxidant potential via the upregulation of SOD2.

Application of Arthrospira platensis for Medicinal Purposes and the Food Industry: A Review of the Literature

Arthrospira platensis is a filamentous cyanobacterium of the class Cyanophyceae and is the most cultivated photosynthetic prokaryote. It is used in the pharmaceutical sector, medicine and the food industry. It has a rich micro- and macro-element composition, containing proteins, lipids, carbohydrates, essential amino acids, polyunsaturated fatty acids, minerals and raw fibers. It is a commonly used ingredient in food products and nutritional supplements. The wide range of biologically active components determines its diverse pharmacological properties (antioxidant, antidiabetic, antimicrobial, antineoplastic, antitumor, anti-inflammatory, photoprotective, antiviral, etc.). This review summarizes research related to the taxonomy, distribution and chemical composition of Arthrospira platensis as well as its potential application in the food and pharmaceutical industries. Attention is drawn to its various medical applications as an antidiabetic and antiobesity agent, with hepatoprotective, antitumor, antimicrobial and antiviral effects as well as regulatory effects on neurodegenerative diseases.

Food and drug industry applications of microalgae Spirulina platensis: A review

Spirulina platensis is a photosynthetic, blue-green, spiral- or bulb-shaped microalgae. Due to the presence of minerals, vitamins, pigments (carotenes, phycocyanin and chlorophyll) proteins (55%-70%), carbohydrates (15%-25%), and essential fatty acids (5%-8%), it has been used as a nutritional supplement for decades. NASA successfully employed it as a nutritional supplement for astronauts on space missions then its popularity was increased. The chemical composition of Spirulina, which is rich in vitamins, minerals, phenolics, vital fatty acids, amino acids, and pigments, can be beneficial to human health when incorporated into meals. The pharmacological effects include antibacterial, anticancer, metalloprotective, immune-stimulating, and antioxidant. It modulates immunological activities and possesses anti-inflammatory qualities by preventing mast cells from releasing histamine. Due to its high quantity of protein, carbohydrate, lipid, vital amino and fatty acids, dietary minerals and vitamins, Spirulina exerts the abovementioned benefits. In this review, up-to-date and possible biological aspects, patents applied on Spirulina and heights of confirmation are addressed, and the extent of current and future exploration is also explored.

Potential of Spirulina platensis as a feed supplement for poultry to enhance growth performance and immune modulation

Increase in drug resistance as well as ineffective immunization efforts against various pathogens (viruses, bacteria and fungi) pose a significant threat to the poultry industry. Spirulina is one of the most widely used natural ingredients which is becoming popular as a nutritional supplement in humans, animals, poultry and aquaculture. It contains protein, vitamins, minerals, fatty acids, pigments, and essential amino acids. Moreover, it also has considerable quantities of unique natural antioxidants including polyphenols, carotenoids, and phycocyanin. Dietary supplementation of Spirulina can beneficially affect gut microbial population, serum biochemical parameters, and growth performance of chicken. Additionally, it contains polyphenolic contents having antibacterial effects. Spirulina extracts might inhibit bacterial motility, invasion, biofilm formation, and quorum sensing in addition to acting directly on the bacterium by weakening and making the bacterial cell walls more porous, subsequently resulting in cytoplasmic content leakage. Additionally, Spirulina has shown antiviral activities against certain common human or animal viruses and this capability can be considered to exhibit potential benefits against avian viruses also. Spirulan, a calcium-rich internal polysaccharide of Spirulina, is potentially responsible for its antiviral effect through inhibiting the entry of several viruses into the host cells, boosting the production of nitric oxide in macrophages, and stimulating the generation of cytokines. Comparatively a greater emphasis has been given to the immune modulatory effects of Spirulina as a feed additive in chicken which might boost disease resistance and improve survival and growth rates, particularly under stress conditions. This manuscript reviews biological activities and immune-stimulating properties of Spirulina and its potential use as a dietary supplement in poultry to enhance growth, gut health and disease resistance.

Screening of Spirulina Components for Anti-Parkinson's and Anti-Alzheimer's Activity by in Silico Methods and Docking Studies

Spirulina platensis was first isolated from Lake Texcoco by Aztecs in the sixteenth century. In 2012, spirulina was considered to be safe dietary supplement by the Food and Drug Administration (FDA). Spirulina is a cyanophytic microalgae that is often considered as single cell protein. It contains many essential amino acids, proteins, fatty acids, antioxidant pigments, carotenoids, and cyanogenic pigments, that is, phycocyanobilins and phycocyanins (Eriksen, Appl Microbiol Biotechnol, 80(1):1-4, 2008). Components of spirulina are investigated for many health benefits and for pharmaceutical uses (Karkos et al., Spirulina in clinical practice: evidence-based human applications). Spirulina has been found to have a role in growth, immunity (Wu et al., Arch Toxicol, 90(8):1817-40, 2016), antioxidant (Wu et al., Arch Toxicol, 90(8):1817-40, 2016), antiviral (Ayehunie et al., J Acquir Immune Defic Syndr Hum Retrovirol, 18(1):7-12, 1998), antitoxicologic, anti-cancerogenic (Hirahashi et al., Int Immunopharmacol, 2(4):423-34, 2002), antidiabetic (Layam and Reddy, Diabetol Croat, 35(2):29-33, 2006), and neuroprotective properties. In this study, we focused on spirulina components in anti-Parkinson's and anti-Alzheimer's activity. Four potential targets, two for each activity, that is, structure of parkinE3 ligase (PDB ID:4I1H) and structure of BACE bound to 5-(3-(5-chloropyridin-3-yl)phenyl)-5-cyclopropyl-2-imino-3-methylimidazolidin-4one (PDBI D:4DJx) for anti-Parkinson's activity and structure of human MAO B in complex with selective inhibitor safinamide (PDB ID:2V5Z) and crystal structure of human BACE-1 in complex with CNP520(PDB ID:6EQM) for anti-Alzheimer's activity, have been selected. The in silico results and scoring of virtual screening, that is, molecular docking, were compared with commonly used marketed drugs such as levodopa for Parkinson's disease (PD) and rivastigmine (Rösler et al., BMJ, 318(7184):633-40, 1999) for Alzheimer's disease.

Recent advances in the bio-application of microalgae-derived biochemical metabolites and development trends of photobioreactor-based culture systems

Microalgae are microscopic algae in sizes ranging from a few micrometers to several hundred micrometers. On average, half of the oxygen in the atmosphere is produced by the photosynthetic process of microalgae, so the role of these microorganisms in the life cycle of the planet is very significant. Pharmaceutical products derived from microalgae and commercial developments of a variety of supplements extracted from them originate from a variety of their specific secondary metabolites. Many of these microalgae are a reservoir of unique biological compounds including carotenoids, antioxidants, fatty acids, polysaccharides, enzymes, polymers, peptides, pigments, toxins and sterols with antimicrobial, antiviral, antifungal, antiparasitic, anticoagulant, and anticancer properties. The present work begins with an introduction of the importance of microalgae in renewable fuels and biodiesel production, the development of healthy food industry, and the creation of optimal conditions for efficient biomass yield. This paper provides the latest research related to microalgae-derived substances in the field of improving drug delivery, immunomodulatory, and anticancer attributes. Also, the latest advances in algal biocompounds to combat the COVID-19 pandemic are presented. In the subject of cultivation and growth of microalgae, the characteristics of different types of photobioreactors, especially their latest forms, are fully discussed along with their advantages and obstacles. Finally, the potential of microalgae biomass in biotechnological applications, biofuel production, as well as various biomass harvesting methods are described.

Arthrospira Enhances Seroclearance in Patients with Chronic Hepatitis B Receiving Nucleos(t)ide Analogue through Modulation of TNF-α/IFN-γ Profile

Chronic hepatitis B (CHB) virus infection, causing immune dysfunction and chronic hepatitis, is one of the leading risk factors for hepatocellular cancer. We investigated how Arthrospira affected hepatitis B surface antigen (HBsAg) reduction in CHB patients under continued nucleos(t)ide analogues (NA). Sixty CHB patients who had been receiving NA for at least one year with undetectable HBV DNA were randomized into three groups: control and oral Arthrospira at 3 or 6 g daily add-on therapy groups. Patients were followed up for 6 months. Oral Arthrospira-diet mice were established to investigate the possible immunological mechanism of Arthrospira against HBV. Within 6 months, mean quantitative HBsAg (qHBsAg) decreased in the oral Arthrospira add-on therapy group. Interestingly, interferon gamma (IFN-γ) increased but TNF-α, interleukin 6 (IL-6), hepatic fibrosis, and steatosis decreased in the add-on groups. In mice, Arthrospira enhanced both innate and adaptive immune system, especially natural killer (NK) cell cytotoxicity, B cell activation, and the interleukin 2 (IL-2), IFN-γ immune response. Arthrospira may modulate IL-2- and TNF-α/IFN-γ-mediated B and T cell activation to reduce HBsAg. Also, Arthrospira has the potential to restore immune tolerance and enhance HBsAg seroclearance in CHB patients through promoting T, B, and NK cell activation.

Fabrication of Dragee Containing Spirulina platensis Microalgae to Enrich Corn Snack and Evaluate Its Sensorial, Physicochemical and Nutritional Properties

In this work, the possibility of enriching snacks with Spirulina palatensis (SP) powder as a dragee was studied. In dragee formulation, the effects of various levels of SP, sunflower oil, NaCl and sour whey powder on sensory, physicochemical and nutritional properties were investigated. The dragee formulation was optimized and the characteristics of the optimal sample were compared with the control sample (containing dragee without SP). The results showed that adding SP increased the flavonoids, total anthocyanin content, vitamins, protein, minerals, essential and non-essential amino acids and fatty acids, including ω3 and ω6, while decreasing the energy intake. Based on the results, the optimal dragee sample was formulated and prepared with a desirability of 0.955. The correlation coefficient indicated that the effective optimization process and the performance of the model were carried out properly. The addition of SP had a significant impact on all color parameters considered by the panelists, and the enriched sample was given a very good taste score (75.10 ± 2.923) and an outstanding overall acceptance rate (91.20 ± 1.549) by the panelists. Although morphological data from scanning electron microscopy showed the distribution of non-uniform SP particles relative to the addition of SP in the extruded product formulation, the preservation of more nutritional properties and the good acceptance of sensory evaluators indicated the success of the application in dragee formulation. Therefore, instead of being utilized in an extruder, we discovered that SP may be used as a dragee for snack fortification.

Health benefits of microalgae and their microbiomes

Microalgae comprise a phylogenetically very diverse group of photosynthetic unicellular pro‐ and eukaryotic organisms growing in marine and other aquatic environments. While they are well explored for the generation of biofuels, their potential as a source of antimicrobial and prebiotic substances have recently received increasing interest. Within this framework, microalgae may offer solutions to the societal challenge we face, concerning the lack of antibiotics treating the growing level of antimicrobial resistant bacteria and fungi in clinical settings. While the vast majority of microalgae and their associated microbiota remain unstudied, they may be a fascinating and rewarding source for novel and more sustainable antimicrobials and alternative molecules and compounds. In this review, we present an overview of the current knowledge on health benefits of microalgae and their associated microbiota. Finally, we describe remaining issues and limitation, and suggest several promising research potentials that should be given attention.

Cyanobacteria and Algae-Derived Bioactive Metabolites as Antiviral Agents: Evidence, Mode of Action, and Scope for Further Expansion; A Comprehensive Review in Light of the SARS-CoV-2 Outbreak

COVID-19—a severe acute respiratory syndrome disease caused by coronavirus 2 (SARS-CoV-2)—has recently attracted global attention, due to its devastating impact, to the point of being declared a pandemic. The search for new natural therapeutic drugs is mandatory, as the screening of already-known antiviral drugs so far has led to poor results. Several species of marine algae have been reported as sources of bioactive metabolites with potential antiviral and immunomodulatory activities, among others. Some of these bioactive metabolites might be able to act as antimicrobial drugs and also against viral infections by inhibiting their replication. Moreover, they could also trigger immunity against viral infection in humans and could be used as protective agents against COVID-In this context, this article reviews the main antiviral activities of bioactive metabolites from marine algae and their potential exploitation as anti-SARS-CoV-2 drugs.

Effects of Spirulina (Arthrospira platensis) as a drinking water supplement during cyclical chronic heat stress on broiler chickens: Assessing algal composition, production, stress, health and immune-biochemical indices

Spirulina, the blue green algae is considered to exhibit multifaceted benefits on both human health and animal production. Three hundred sixty day old unsexed broiler chicks of CARIBROVISHAL strain were assigned to five treatment groups each comprising nine replicates of 8 chicks. The experiment was carried out during the hot humid summer season (Mid-April to May) under deep litter rearing system with uniform managemental conditions. Birds were administered orally with Spirulina through drinking water in the morning (06:00-12:00 PM) on daily basis throughout the experimental period at 5, 10, 15 and 20 gL^-1 concentration. Spirulina supplementation neither improved nor compromised production performance of broilers reared during hot climatic condition. Results based on one way analysis of variance indicated a significant effect on haemoglobin and total red blood cell count. Serum lipid content and transaminases were reduced, while serum protein concentration was higher (P < 0.01) in the groups administered with 15 and 20 gL^-1 of Spirulina. The extent of imparting shank pigmentation was improved in all the supplemented groups. Cell mediated and humoral immunity against Phytoheamagglutunin-P and Newcastle disease vaccination respectively were maximized (P < 0.05) at 20 gL^-1. These findings provide direct evidence of dose-related modulation of production, physiological and immunological attributes by Spirulina engendering its further investigation as a potential source of drinking water supplement for stress alleviation in broilers. From the results, it may concluded that Spirulina can be incorporated at 15 or 20 gL^-1 for achieving optimal improvement of health and welfare attributes in broilers reared during hot summer without compromising production.

The protective impacts of Spirulina platensis against cisplatin-induced renal injury through the regulation of oxidative stress, pro-inflammatory cytokines and Bax/Bcl2

One of the main antineoplastic chemotherapy medications is cisplatin, of which nephropathy is a major side effect. In this current study, we aim to investigate the molecular protective effect of Spirulina platensis (SP) on cisplatin-induced nephrotoxicity. In total, 48 healthy male albino rats were allocated into 4 groups. Group 1 received saline intraperitoneally (IP) twice per week (normal rats). Group 2 received SP (100 mg/kg BW orally). Group 3 were injected with cisplatin (1.5 mg/kg IP) twice per week. Group 4 received SP and on the 4th day received cisplatin (1.5 mg/kg IP) for 21 days. After 3 weeks of experiment, blood and renal tissues were taken for serum analysis, gene expression using qRT-polymerase chain reaction, and renal histopathology. As per our findings, it was found that SP significantly ameliorated the alterations in body weight, relative kidney weight, and the disturbance in examined renal markers. Furthermore, SP recovered and restored cisplatin-induced oxidative stress biomarkers (MDA and NO) and antioxidant activity (SOD and GSH) and cisplatin-induced upregulation in the gene expression of TNF-α, inducible nitric oxide synthase, TGF1-β, IL-1β, and IL-6. Interestingly, these gene expressions were ameliorated by the SP pre-administration. Furthermore, cisplatin upregulated pro-apoptotic gene Bax, whereas it downregulated anti-apoptotic gene Bcl2. Interestingly, SP mitigated this alteration in apoptosis and anti-apoptotic associated genes. Renal histopathology revealed the protective impacts of SP against cisplatin-induced severe glomerular congestion, hemorrhage, inflammatory cell infiltration, degeneration, and severe necrosis in renal glomeruli and tubules. In conclusion, SP has a protective effect against cisplatin-induced renal damage through modulating oxidative stress and anti-inflammatory, anti-necrotic, and anti-apoptotic-associated genes.

Separation, Purification, Structure Analysis, In Vitro Antioxidant Activity and circRNA-miRNA-mRNA Regulatory Network on PRV-Infected RAW264.7 Cells of a Polysaccharide Derived from Arthrospira platensis

To investigate the structure of Arthrospira platensis polysaccharide (PAP) (intracellular polysaccharide) and the antioxidant activity of the first component of PAP (PAP-1) on pseudorabies virus (PRV) -infected RAW264.7 cells. The PAP was separated and purified by the Cellulose DE-52 chromatography column and Sephacryl S-200 high-resolution gel column to obtain PAP-1. The antioxidant activity and regulation of PAP-1 on PRV-infected RAW264.7 cells of circRNA-miRNA-mRNA network were investigated by chemical kit, Q-PCR, and ce-RNA seq. The results indicated that the molecular weight (Mw) of PAP-1, which was mainly composed of glucose and eight other monosaccharides, was 1.48 × 106 Da. The main glycosidic bond structure of PAP-1 was →4)-α-D-Glcp-(1→. PAP-1 may be increased the antioxidant capacity by regulating the circRNA-miRNA-mRNA network in PRV-infected RAW264.7 cells. This study provided a scientific foundation for further exploring the antioxidant activity of PAP-1 based on its structure.

Galactosyldiacylglycerols: From a Photosynthesis-Associated Apparatus to Structure-Defined In Vitro Assembling

Being ubiquitously present in plants, microalgae, and cyanobacteria and as the major constituents of thylakoid membranes, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) make up approximately 52 and 26%, respectively, of chloroplast lipids. Thylakoid membranes harbor the photosynthetic complexes and numerous essential biochemical pathways where MGDG and DGDG play a central role in facilitating photosynthesis light reaction, maintaining chloroplast morphology, and responding to abiotic stresses. Furthermore, these galactolipids are also bioactive compounds with antitumor, antimicrobial, antiviral, immunosuppressive, and anti-inflammatory activities and important nutritional value. These characteristics are strictly dependent upon their fatty acyl chain length, olefinic nature, and stereoconfiguration. However, their application potentials are practically untapped, largely as a result of the fact that their availability in large quantity and high purity (structured galactolipids) is challenging. In addition to laborious extraction from natural sources, in vitro assembling of these molecules could be a promising alternative. Thus, this review updates the latest advances in elucidating biosynthesis paths of MGDG and DGDG and related enzyme systems, which present invaluable inspiration to design approaches for a retrosynthesis of galactolipids. More critically, this work summarizes recent developments in the biological and enzymatic syntheses of galactolipids, especially the strategic scenarios for the construction of in vitro enzymatic and/or chemoenzymatic synthesis routes. Protein engineering of enzymes involved in the synthesis of MGDG and DGDG to improve their properties is highlighted, and the applications of galactolipids in foods and medicine are also discussed.

Physicochemical Evaluation of Edible Cyanobacterium Arthrospira platensis Collected from the South Atlantic Coast of Morocco: A Promising Source of Dietary Supplements

The cyanobacterium Arthrospira platensis (A. platensis)—a genus of nonheterocystous filamentous cyanobacteria—is used in industrial applications and as a food supply. The current research work aims to study the physicochemical characteristics of A. platensis indigenous to the Moroccan Atlantic coast at Laayoune (Foum El Oued lagoon). The contents of proteins, carbohydrates, vitamins, lipids, minerals, heavy metals, energy value, humidity, ash, pigments, and tannins in A. platensis were investigated using protocols as described in the earlier literature. The values of protein, carbohydrate, and lipid contents in A. platensis were 58.9 ± 0.07, 14.67, and 45.54% respectively. The values of vitamins B₂ and B₃ dosed in A. platensis were 1.31 ± 0.19 and 30.8 ± 0.001 mg/kg, respectively. The values of heavy metals including lead and chromium were 70 ± 4.5 and 5 ± 0.5 PPB (parts-per-billion), respectively; however, no trace concerning cadmium was detected. The values of energy value, humidity, and ash content were 346.48 ± 0.21, 11.6 ± 0.17%, and 9.1 ± 0.21% kcal/100 g, respectively. The results of pigment content showed the presence of chlorophyll b, chlorophyll a, and carotenoids of 37.506 ± 3.38, 26.066 ± 3.08, and 9.52 ± 0.22 mg/g, respectively. The results obtained revealed that A. platensis indigenous to the Moroccan Atlantic coast at Laayoune was found to be very rich in proteins, carbohydrates, vitamins, minerals, ash, and pigments and lower in heavy metals and saturated fats when compared with species investigated in the literature. Thus, A. platensis indigenous to the Moroccan Atlantic coast at Laayoune fulfills the requirements for being used as dietary supplements.

Evaluating Anticancer and Immunomodulatory Effects of Spirulina (Arthrospira) platensis and Gamma-Tocotrienol Supplementation in a Syngeneic Mouse Model of Breast Cancer

Nutrition can modulate host immune responses as well as promote anticancer effects. In this study, two nutritional supplements, namely gamma-tocotrienol (γT3) and Spirulina, were evaluated for their immune-enhancing and anticancer effects in a syngeneic mouse model of breast cancer (BC). Five-week-old female BALB/c mice were fed Spirulina, γT3, or a combination of Spirulina and γT3 (Spirulina + γT3) for 56 days. The mice were inoculated with 4T1 cells into their mammary fat pad on day 28 to induce BC. The animals were culled on day 56 for various analyses. A significant reduction (p < 0.05) in tumor volume was only observed on day 37 and 49 in animals fed with the combination of γT3 + Spirulina. There was a marked increase (p < 0.05) of CD4/CD127+ T-cells and decrease (p < 0.05) of T-regulatory cells in peripheral blood from mice fed with either γT3 or Spirulina. The breast tissue of the combined group showed abundant areas of necrosis, but did not prevent metastasis to the liver. Although there was a significant increase (p < 0.05) of MIG-6 and Cadherin 13 expression in tumors from γT3-fed animals, there were no significant (p > 0.05) differences in the expression of MIG-6, Cadherin 13, BIRC5, and Serpine1 upon combined feeding. This showed that combined γT3 + Spirulina treatment did not show any synergistic anticancer effects in this study model.

Supplementation of Diets With Spirulina Influences Immune and Gut Function in Dogs

Spirulina refers to two species of blue green algae (Arthrospira platensis, and A. maxima) consumed by humans as food for centuries. While, Spirulina has been shown to have immune enhancing properties in several animal and human studies, there are no systematic studies in dogs. The aim of this study was to evaluate the immunomodulatory effect of dietary supplementation with Spirulina in dogs. The study was conducted in two phases: Pre-test (8 wks.) and Test (42 wks.). Thirty adult dogs (mean 2.9 yrs.) were randomized into two groups and fed a nutritionally complete diet in the “Pre-test” phase. At the end of “Pre-test” phase all dogs received a rabies vaccine, and dogs in “test group” were switched to diet supplemented with dried Arthrospira platensis (Spirulina). Response to rabies vaccine was evaluated by Rapid Fluorescent Focus Inhibition Test (RFFIT). Gut immune response was assessed by measuring fecal IgA. Gut microbiota was evaluated by Temporal Temperature Gel Electrophoresis (TTGE) methodology. Repeated measures ANOVA was used to test for differences between groups and statistical significance considered to be p < 0.05. Dogs fed diets supplemented with Spirulina demonstrated enhanced immune status by showing significantly higher vaccine response and higher levels of fecal IgA as compared to the control group. Supplementing diets with Spirulina also resulted in significantly increased gut microbiota stability in the test group. In conclusion, diets supplemented with Spirulina significantly enhanced immune response and gut health in dogs.

Antioxidant and Inflammatory Gene Expression Profiles of Bovine Peripheral Blood Mononuclear Cells in Response to Arthrospira platensis before and after LPS Challenge

Oxidative stress and inflammatory diseases are closely related processes that need to be controlled to ensure the desirable high performance of livestock. The microalga spirulina has shown antioxidant and anti-inflammatory properties in monogastric species. To investigate potential beneficial effects in ruminants, we replaced soybean meal (SOY) in the diets of dairy cows and fattening bulls by spirulina (SPI) and analyzed plasma concentrations of antioxidants (β-carotene, α-tocopherol, polyphenols) and serum total antioxidant capacity. Following in vitro stimulation with lipopolysaccharide (LPS), peripheral blood mononuclear cells (PBMCs) were isolated for expression analysis of inflammation- and antioxidant-defense-related genes. Plasma β-carotene concentration was higher in SPI, compared to SOY cows, but did not differ in bulls. Plasma total phenol concentration was significantly higher in SPI, compared to SOY bulls, but not in cows. Stimulation of bovine PBMCs with LPS increased the expression of most cytokines and some antioxidant enzymes. Gene expression of PBMCs derived from SPI animals, compared to SOY animals, hardly differed. Our results indicate that in ruminants, spirulina might not have potent antioxidant and anti-inflammatory properties. Future studies should evaluate the microbial degradation of spirulina and its bioactive compounds in the rumen to provide further data on potential beneficial health effects in ruminants.

The effects of immunostimulatory herbal supplements on autoimmune skin diseases

The use of herbal supplements that promise to improve immune health has gained popularity among dermatology patients. However, there is little to no evidence that herbal supplements improve dermatologic conditions. Several in vitro and in vivo studies have shown that Spirulina platensis, Aphanizomenon flos-aqua, Chlorella, Echinacea, and alfalfa activate immune cells via certain cytokines and chemokines. Case reports suggest the association of ingesting immunostimulatory herbs and the clinical onset or flares of diseases characterized by an exaggerated immune response such as lupus erythematosus, dermatomyositis, and autoimmune blistering disorders. Therefore, it is imperative to investigate the prevalence of herbal supplement use in this patient population. In addition, in vitro studies should examine the underlying mechanisms by which herbs stimulate immune pathways that are already overactive in autoimmune patients.

Effects of fluctuating temperature in open raceway ponds on the biomass accumulation and harvest efficiency of Spirulina in large-scale cultivation

It is of great significance to select strains with wide adaptability to temperature range for large-scale commercial cultivation of Spirulina. The aim of this study was to comprehend how the strain H-208 grew and whether this strain had any advantages in temperature adaptation compared with local production strain during the large-scale cultivation in Inner Mongolia. The results showed that the strain H-208 could adapt to the new environmental condition quickly, and the daily average biomass dry weight of strain H-208 was 49% and 52% more than that of production strain M-1 in first cycle (20.24 g/m2/day) and second cycle (16.90 g/m2/day) of acclimation experiment, respectively. The growth rate of strain H-208 was 0.055 and 0.066 g/L/day from July 22 to July 25 and from July 26 to July 29, respectively, while the growth rate of strain M-1 was only 0.036 and 0.032 g/L/day, respectively, during the same cultured days in 605-m2 raceway ponds before high temperature. The harvesting efficiency of H-208 and M-1 was 95.1% and 72.1% before high temperature, and that was 95.3% and 52.5% after being stressed by high temperature, respectively. Meanwhile, it was also observed that the filaments of the two strains contracted and their pitches were smaller than that before high temperature stress, especially the strain M-1. In 20-m2 raceway ponds of recovery experiment after high temperature, the percentage of daily average biomass dry weight of strain H-208 was 68% more than that of strain M-1, which demonstrated that strain H-208 could recover and grow rapidly, and its self-regulation ability was superior to that of strain M-1.

The Effects of Spirulina Supplementation on Redox Status and Performance Following a Muscle Damaging Protocol

Spirulina plantensis is a popular supplement which has been shown to have antioxidant and performance enhancing properties. The purpose of this study was to evaluate the effects of spirulina supplementation on (a) redox status (b) muscle performance and (c) muscle damage following an eccentric bout of exercise that would induce muscle damage. Twenty-four healthy, recreationally trained males participated in the study and were randomly separated into two groups: a spirulina supplementation (6 g per day) and a placebo group. Both groups performed an eccentric bout of exercise consisting of 5 sets and 15 maximum reps per set. Blood was collected at 24, 48, 72 and 96 h after the bout and total antioxidant capacity (TAC) and protein carbonyls (PC) were assessed in plasma. Delayed onset muscle soreness (DOMS) was also assessed at the same aforementioned time points. Eccentric peak torque (EPT) was evaluated immediately after exercise, as well as at 24, 48, 72 and 96 h post exercise. Redox status indices (TAC and PC) did not change significantly at any time point post exercise. DOMS increased significantly 24 h post exercise and remained elevated until 72 h and 96 h post exercise for the placebo and spirulina group, respectively. EPT decreased significantly and immediately post exercise and remained significantly lower compared to baseline until 72 h post exercise. No significant differences between groups were found for DOMS and EPT. These results indicate that spirulina supplementation following a muscle damaging protocol does not confer beneficial effects on redox status, muscle performance or damage.

Antiviral Cyanometabolites-A Review

Global processes, such as climate change, frequent and distant travelling and population growth, increase the risk of viral infection spread. Unfortunately, the number of effective and accessible medicines for the prevention and treatment of these infections is limited. Therefore, in recent years, efforts have been intensified to develop new antiviral medicines or vaccines. In this review article, the structure and activity of the most promising antiviral cyanobacterial products are presented. The antiviral cyanometabolites are mainly active against the human immunodeficiency virus (HIV) and other enveloped viruses such as herpes simplex virus (HSV), Ebola or the influenza viruses. The majority of the metabolites are classified as lectins, monomeric or dimeric proteins with unique amino acid sequences. They all show activity at the nanomolar range but differ in carbohydrate specificity and recognize a different epitope on high mannose oligosaccharides. The cyanobacterial lectins include cyanovirin-N (CV-N), scytovirin (SVN), microvirin (MVN), Microcystisviridis lectin (MVL), and Oscillatoria agardhii agglutinin (OAA). Cyanobacterial polysaccharides, peptides, and other metabolites also have potential to be used as antiviral drugs. The sulfated polysaccharide, calcium spirulan (CA-SP), inhibited infection by enveloped viruses, stimulated the immune system’s response, and showed antitumor activity. Microginins, the linear peptides, inhibit angiotensin-converting enzyme (ACE), therefore, their use in the treatment of COVID-19 patients with injury of the ACE2 expressing organs is considered. In addition, many cyanobacterial extracts were revealed to have antiviral activities, but the active agents have not been identified. This fact provides a good basis for further studies on the therapeutic potential of these microorganisms.

Environmental triggers of dermatomyositis: a narrative review

Dermatomyositis (DM) is an autoimmune disease that affects the skin, lungs, and muscle. Although the pathogenesis of DM is not completely understood, several environmental triggers have been linked to DM onset or flare. This article specifically examines the effects of herbal supplements, drugs, infections, ultraviolet (UV) radiation, and environmental pollutants on the onset or exacerbation of DM. Herbal supplements such as Spirulina platensis, Aphanizomenon flos-aquae, Chlorella, Echinacea, and Alfalfa have been implicated and are frequently used in health foods. Medications such as hydroxyurea, TNF-α inhibitors, immune checkpoint inhibitors (ICI), and penicillamine, as well as certain viral infections, such as parvovirus B19, coxsackie virus, polyomavirus, Epstein-Barr virus (EBV), hepatitis, influenza, and human immunodeficiency viruses (HIV) have been associated with DM onset. Bacterial infections and vaccinations have also been linked to the development of DM. Additional environmental factors, including UV radiation and air pollutants, such as silica, biological/mineral dust, and particulate air matter from vehicle and industrial emissions, may also play a role in DM pathogenesis. Overall, there is general agreement that an autoimmune attack of the skin, muscle, and lungs in DM can be triggered by various environmental factors and warrants further investigation.

Traditional foods with their constituent's antiviral and immune system modulating properties

Background

Viruses are responsible for several diseases, including severe acute respiratory syndrome, a condition caused by today's pandemic coronavirus disease (COVID-19). A negotiated immune system is a common risk factor for all viral infections, including COVID-19. To date, no specific therapies or vaccines have been approved for coronavirus. In these circumstances, antiviral and immune boosting foods may ensure protection against viral infections, especially SARS-CoV-2 by reducing risk and ensuring fast healing of SARS-CoV-2 illness.

Scope and approach

In this review, we have conducted an online search using several search engines (Google Scholar, PubMed, Web of Science and Science Direct) to find out some traditional foods (plant, animal and fungi species), which have antiviral and immune-boosting properties against numerous viral infections, particularly coronaviruses (CoVs) and others RNA-virus infections. Our review indicated some foods to be considered as potential immune enhancers, which may help individuals to overcome viral infections like COVID-19 by modulating immune systems and reducing respiratory problems. Furthermore, this review will provide information regarding biological properties of conventional foods and their ingredients to uphold general health.

Key Findings and Conclusions

We observed some foods with antiviral and immune-boosting properties, which possess bioactive compounds that showed significant antiviral properties against different viruses, particularly RNA viruses such as CoVs. Interestingly, some antiviral and immune-boosting mechanisms were very much similar to the antiviral drug of COVID-19 homologous SARS (Severe Acute Respiratory Syndrome Coronavirus) and MERS (Middle East Respiratory Syndrome Coronavirus). The transient nature and the devastating spreading capability of COVID-19 lead to ineffectiveness of many curative therapies. Therefore, body shielding and immune-modulating foods, which have previous scientific recognition, have been discussed in this review to discern the efficacy of these foods against viral infections, especially SARS-CoV-2.

Prospective options of algae-derived nutraceuticals as supplements to combat COVID-19 and human coronavirus diseases

The outbreak of the coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 that has created huge trepidation worldwide, has a mortality rate of 0.5% to 1% and is growing incessantly. There are currently no therapies and/or vaccines that may help abate this viral disease, but the use of masks and social distancing can limit the spread. Boosting immunity has been a simple way to resist viral infection and limit fatalities. In this context, the use of nutraceuticals appears to be a potential panacea. The ability of algae-based nutraceuticals, mainly Spirulina, to boost immunity against viral diseases has already been reported clinically. Spirulina-based nutraceuticals boost the adaptive and innate immunity, and bioactive compounds, such as angiotensin-converting enzyme (ACE) inhibitor peptides, phycobiliproteins, sulfated polysaccharides, and calcium-Spirulan, can serve as antiviral agents. The presence of these molecules indicates its potential role in resisting infection and COVID-19 disease progression. This review focuses on the potential role of algal nutraceuticals as immune boosters to combat the human coronavirus and other viral diseases. The potential use of Spirulina-based nutraceuticals for combating COVID-19, its mechanism, and future directions have also been discussed.

Postulated Adjuvant Therapeutic Strategies for COVID-19

The number of COVID-19 patients is still growing exponentially worldwide due to the high transmissibility of the SARS-CoV-2 virus. Therapeutic agents currently under investigation are antiviral drugs, vaccines, and other adjuvants that could relieve symptoms or improve the healing process. In this review, twelve therapeutic agents that could play a role in prophylaxis or improvement of the COVID-19-associated symptoms (as add-on substances) are discussed. Agents were identified based on their known pharmacologic mechanism of action in viral and/or nonviral fields and are postulated to interact with one or more of the seven known mechanisms associated with the SARS-CoV-2 virus: (i) regulation of the immune system; (ii) virus entrance in the cell; (iii) virus replication; (iv) hyperinflammation; (v) oxidative stress; (vi) thrombosis; and (vii) endotheliitis. Selected agents were immune transfer factor (oligo- and polypeptides from porcine spleen, ultrafiltered at <10 kDa; Imuno TF®), anti-inflammatory natural blend (Uncaria tomentosa, Endopleura uchi and Haematoccocus pluvialis; Miodesin®), zinc, selenium, ascorbic acid, cholecalciferol, ferulic acid, spirulina, N-acetylcysteine, glucosamine sulfate potassium hydrochloride, trans-resveratrol, and maltodextrin-stabilized orthosilicic acid (SiliciuMax®). This review gives the scientific background on the hypothesis that these therapeutic agents can act in synergy in the prevention and improvement of COVID-19-associated symptoms.

Protective effects of pharmacological agents against aminoglycoside-induced nephrotoxicity: A systematic review

Introduction: Aminoglycosides have been long used for antibacterial treatment and are still commonly used in clinical practice. Despite their extensive application and positive effects, drug-related toxicity is considered as the main obstacle for aminoglycosides. Aminoglycosides induce nephrotoxicity through the endocytosis and accumulation of the antibiotics in the epithelial cells of proximal tubule. Most importantly, however, a number of pharmacological agents were demonstrated to have protective activities against nephrotoxicity in experimental animals.Areas covered: In the present systematic review, the authors provide and discuss the mechanisms and epidemiological features of aminoglycoside-induced nephrotoxicity, and focus mainly on recent discoveries and key features of pharmacological interventions. In total, 39 articles were included in this review.Expert opinion: The majority of studies investigated gentamicin-induced nephrotoxicity in animal models. Antioxidants, chemicals, synthetic drugs, hormones, vitamins, and minerals showed potential values to prevent gentamicin-induced nephrotoxicity. Indicators used to evaluate the effectiveness of nephroprotection included antioxidative indexes, inflammatory responses, and apoptotic markers. Among the nephroprotective agents studied, herbs and natural antioxidant agents showed excellent potential to provide a protective strategy against gentamicin-induced nephrotoxicity.

Microalgae with Immunomodulatory Activities

Microalgae are photosynthetic microorganisms adapted to live in very different environments and showing an enormous biochemical and genetic diversity, thus representing an excellent source of new natural products with possible applications in several biotechnological sectors. Microalgae-derived compounds have shown several properties, such as anticancer, antimicrobial, anti-inflammatory, and immunomodulatory. In the last decade, compounds stimulating the immune system, both innate immune response and adaptive immune response, have been used to prevent and fight various pathologies, including cancer (cancer immunotherapy). In this review we report the microalgae that have been shown to possess immunomodulatory properties, the cells and the cellular mediators involved in the mechanisms of action and the experimental models used to test immunostimulatory activities. We also report information on fractions or pure compounds from microalgae identified as having immunostimulatory activity. Given the increasing interest in microalgae as new eco-friendly source of bioactive compounds, we also discuss their possible role as source of new classes of promising drugs to treat human pathologies.

Impacts of dietary microalgae (Schizochytrium JB5) on growth performance, blood profiles, apparent total tract digestibility, and ileal nutrient digestibility in weaning pigs

BACKGROUND

Microalgae can serve as an alternative to animal feed additives or supplements in the diet of weaning pigs, to increase their potential and performance. Two experiments were conducted with three dietary treatments: CON (basal diet), MA1 (basal diet + 0.5% microalgae), and MA2 (basal diet + 1.0% microalgae). In Experiment 1, 150 crossbred weaning pigs were used in a 5-week experiment. In Experiment 2, 15 cannulated barrows were used. The objective of this study was to determine the effects of dietary supplementation of Schizochytrium microalgae on growth performance, blood profiles, apparent total tract digestibility, and ileal nutrient digestibility in weaning pigs.

RESULTS

In Experiment 1, pigs fed with MA2 had higher growth (P < 0.05) than pigs fed with MA1 from day 8 to day 21 but the experimental result showed no significant effects (P > 0.05) on growth performance, white blood cell, total cholesterol, and triglyceride among the treatments. However, lymphocytes (%) of pigs fed with MA1 and MA2 diets were significantly higher (P < 0.05) than those of pigs fed with a CON diet at day 35. In Experiment 2, the apparent total tract digestibility and ileal nutrient digestibility of dry matter and nitrogen were higher (P < 0.05) in pigs fed with MA1 and MA2 than in those fed with a CON diet.

CONCLUSION

Dietary microalgae supplementation had more dramatic and beneficial effects on nutrient digestibility than a CON diet. It also increased lymphocyte concentration but had no significant effect on growth performance in weaning pigs. © 2019 Society of Chemical Industry.

Dose Effects of Orally Administered Spirulina Suspension on Colonic Microbiota in Healthy Mice

Oral supplemented nutraceuticals derived from food sources are surmised to improve the human health through interaction with the gastrointestinal bacteria. However, the lack of fundamental quality control and authoritative consensus (e.g., formulation, route of administration, dose, and dosage regimen) of these non-medical yet bioactive compounds are one of the main practical issues resulting in inconsistent individual responsiveness and confounded clinical outcomes of consuming nutraceuticals. Herein, we studied the dose effects of widely used food supplement, microalgae spirulina (Arthrospira platensis), on the colonic microbiota and physiological responses in healthy male Balb/c mice. Based on the analysis of 16s rDNA sequencing, compared to the saline-treated group, oral administration of spirulina once daily for 24 consecutive days altered the diversity, structure, and composition of colonic microbial community at the genus level. More importantly, the abundance of microbial taxa was markedly differentiated at the low (1.5 g/kg) and high (3.0 g/kg) dose of spirulina, among which the relative abundance of Clostridium XIVa, Desulfovibrio, Eubacterium, Barnesiella, Bacteroides, and Flavonifractor were modulated at various degrees. Evaluation of serum biomarkers in mice at the end of spirulina intervention showed reduced the oxidative stress and the blood lipid levels and increased the level of appetite controlling hormone leptin in a dose-response manner, which exhibited the significant correlation with differentially abundant microbiota taxa in the cecum. These findings provide direct evidences of dose-related modulation of gut microbiota and physiological states by spirulina, engendering its future mechanistic investigation of spirulina as potential sources of prebiotics for beneficial health effects via the interaction with gut microbiota.

The impact of several hydraulic fracking chemicals on Nile tilapia and evaluation of the protective effects of Spirulina platensis

Hydraulic fracturing (fracking) chemicals are used to maximize the extraction of hard-to-reach underground energy resources. Large amounts of fracking fluid could escape to the surrounding environments, including underground and surface water resources, during the chemical mixing stage of the hydraulic fracturing water cycle due to equipment failure or human error. However, the impact of pollution resulting from operational discharges is difficult to assess in aquatic ecosystems. In this study, pathological investigations, chromosomal aberrations, DNA damage, and biochemical and hematological parameters were used to evaluate the effects of such chemicals on Nile tilapia. Chromosomal aberrations are considered very sensitive genetic markers of exposure to genotoxic chemicals and are used as indicators of DNA damage. The appearance of different types of chromosomal aberrations (gaps and breaks) due to chemical exposure was significantly reduced by treatment with spirulina. Various deleterious findings in Nile tilapia, in the current study, could attributed to the presence of fracking chemicals in the aquatic environment. However, the presence of spirulina in the diet reduced the hazards of such chemicals. In addition, cytogenetic studies in the current work revealed the importance of spirulina in ameliorating the genotoxic effects of a mixture of some chemicals used in fracking.

Replacement of fishmeal by spirulina Arthrospira platensis affects growth, immune related-gene expression in gibel carp (Carassius auratus gibelio var. CAS III), and its challenge against Aeromonas hydrophila infection

The present study examined the effect of dietary spirulina, Arthrospira platensis on growth performance, blood physiological indices, immune-related gene expressions and resistance of juvenile gibel carp against Aeromonas hydrophila infection. Four isonitrogenous (360 g kg^-1) and isolipidic (90 g kg^-1) diets were formulated with containing different levels of spirulina powder of 0 g (SP0, the control diet), 3.38 g (SP3.38), 6.76 g (SP6.76) and 13.52 g (SP13.52) per 100 g diet to replace 0%, 25%, 50% and 100% of fishmeal protein, respectively. And each diet was randomly assigned to triplicate tanks (150-L capacity per each) and each tank was stocked with 22 fish (15.37 ± 0.06 g). Fish were fed one of the tested diets up to satiation twice a day for 46 days. A challenge test was carried out after the feeding trial by injecting Aeromonas hydrophila intraperitoneally for 7 days. The results showed that fish growth, feeding rate in groups SP3.38 and SP6.76 were significantly higher than those of groups SP0 and SP13.52 (P < 0.05). Feed efficiency and protein retention rate had no significant difference among all tested groups. Plasma superoxide dismutase and phagocyte activity of blood leukocytes significantly increased in the spirulina-fed fish groups at 12-h post the bacterial challenge (P < 0.05). Both pre and post challenge test, plasma lysozyme activities in spirulina-fed groups were significantly higher than that in the control group (P < 0.05). Plasma malondialdehyde got the lowest value in the SP13.52 group before and after the challenge test. The transcriptional levels of TLR2 (Toll like receptor 2), myeloid differentiation factor 88 (MyD88), Toll/IL-1 receptor domain-containing adaptor protein (TIRAP), interleukin-1β (IL-1β) and tumor necrosis factor-α1 (TNF-α1) in spleen and kidney significantly increased post the bacterial challenge compared to the pre challenge. And the relative expressions of the immune-related genes of spirulina-fed fish groups were higher than those of the control group before and after the challenge test. The 7-day cumulative survival rate after the bacterial challenge was highest in the SP3.38 group (P < 0.05). The present results indicated that low dietary inclusion of spirulina significantly enhanced the immune response of gibel carp partly through TLR2 pathway and 3.38% of dietary spirulina was recommended for the juveniles based on the growth and immune response.