Effect of combination of chlorella intake and aerobic exercise training on glycemic control in type 2 diabetic rats

Effects of physical training on the metabolic profile of rats exposed to chronic restraint stress

INTRODUCTION

Despite strong evidences supporting the protective role of exercise against stress-induced repercussions, the literature remains inconclusive regarding metabolic aspects. Therefore, this study aimed to evaluate the effect of Physical Training (PT) by swimming on the metabolic parameters of rats subjected to restraint stress.

METHODS

Wistar rats (n = 40) were divided into four groups: Control (C), Trained (T), Stressed (S), and Trained/Stressed (TS). The restraint stress protocol involved confining the animals in PVC pipes for 60 minutes/day for 12 weeks. Concurrently, the swimming PT protocol was performed without additional load in entailed sessions of 60 minutes conducted five days a week for the same duration. The following parameters were analyzed: fitness progression assessed by the physical capacity test, body mass, serum level of glucose, triglyceride, cholesterol and corticosterone, as well as glycemic tolerance test, evaluated after glucose administration (2 g/kg, i.p.).

RESULTS

Trained groups (T and TS) exhibited enhanced physical capacity (169 ± 21 and 162 ± 22% increase, respectively) compared to untrained groups (C: 9 ± 5 and S: 11 ± 13% increase). Corticosterone levels were significantly higher in the S group (335 ± 9 nmoL/L) compared to C (141 ± 3 nmoL/L), T (174 ± 3 nmoL/L) and TS (231 ± 7 nmoL/L), which did not differ from each other. There were no significant changes in serum glucose, cholesterol, and triglyceride levels among the groups. However, the glycemic curve after glucose loading revealed increased glycemia in the S group (area under curve 913 ± 30 AU) but the TS group exhibited values (673 ± 12 AU) similar to the groups C (644 ± 10 AU) and T (649 ± 9 AU).

CONCLUSION

Swimming-based training attenuated stress-induced corticosterone release and prevented glucose intolerance in rats, reinforcing the importance of exercise as a potential strategy to mitigate the pathophysiological effects of stress.

Potential benefits of microalgae intake against metabolic diseases: beyond spirulina-a systematic review of animal studies

CONTEXT

Microalgae are a diverse source of bioactive molecules, such as polyphenols, carotenoids, and omega-3 fatty acids, with beneficial properties in biomarkers of metabolic diseases. Unlike the rest of the microalgae genera, Arthrospira sp., commonly called spirulina, has been widely studied.

OBJECTIVE

This review aims to describe the current knowledge about microalgae, besides spirulina, focusing on their beneficial properties against metabolic diseases.

DATA SOURCES

A systematic research of MEDLINE (via PubMed), Cochrane, and Scopus databases was conducted to identify relevant studies published after January 2012. In vivo animal studies including microalgae consumption, except for spirulina, that significantly improved altered biomarkers related to metabolic diseases were included. These biomarkers included body weight/composition, glucose metabolism, lipid metabolism, oxidative damage, inflammation markers, and gut microbiota.

DATA EXTRACTION

After the literature search and the implementation of inclusion and exclusion criteria, 37 studies were included in the revision out of the 132 results originally obtained after the application of the equation on the different databases.

DATA ANALYSIS

Data containing 15 microalgae genera were included reporting on a wide range of beneficial results at different levels, including a decrease in body weight and changes in plasma levels of glucose and lipoproteins due to molecular alterations such as those related to gene expression regulation. The most reported beneficial effects were related to gut microbiota and inflammation followed by lipid and glucose metabolism and body weight/composition.

CONCLUSIONS

Microalgae intake improved different altered biomarkers due to metabolic diseases and seem to have potential in the design of enriched foodstuffs or novel nutraceuticals. Nevertheless, to advance to clinical trials, more thorough/detailed studies should be performed on some of the microalgae genera included in this review to collect more information on their molecular mechanisms of action.

Bioactivity of Macronutrients from Chlorella in Physical Exercise

Chlorella is a marine microalga rich in proteins and containing all the essential amino acids. Chlorella also contains fiber and other polysaccharides, as well as polyunsaturated fatty acids such as linoleic acid and alpha-linolenic acid. The proportion of the different macronutrients in Chlorella can be modulated by altering the conditions in which it is cultured. The bioactivities of these macronutrients make Chlorella a good candidate food to include in regular diets or as the basis of dietary supplements in exercise-related nutrition both for recreational exercisers and professional athletes. This paper reviews current knowledge of the effects of the macronutrients in Chlorella on physical exercise, specifically their impact on performance and recovery. In general, consuming Chlorella improves both anaerobic and aerobic exercise performance as well as physical stamina and reduces fatigue. These effects seem to be related to the antioxidant, anti-inflammatory, and metabolic activity of all its macronutrients, while each component of Chlorella contributes its bioactivity via a specific action. Chlorella is an excellent dietary source of high-quality protein in the context of physical exercise, as dietary proteins increase satiety, activation of the anabolic mTOR (mammalian Target of Rapamycin) pathway in skeletal muscle, and the thermic effects of meals. Chlorella proteins also increase intramuscular free amino acid levels and enhance the ability of the muscles to utilize them during exercise. Fiber from Chlorella increases the diversity of the gut microbiota, which helps control body weight and maintain intestinal barrier integrity, and the production of short-chain fatty acids (SCFAs), which improve physical performance. Polyunsaturated fatty acids (PUFAs) from Chlorella contribute to endothelial protection and modulate the fluidity and rigidity of cell membranes, which may improve performance. Ultimately, in contrast to several other nutritional sources, the use of Chlorella to provide high-quality protein, dietary fiber, and bioactive fatty acids may also significantly contribute to a sustainable world through the fixation of carbon dioxide and a reduction of the amount of land used to produce animal feed.

Aerobic exercise training-induced follistatin-like 1 secretion in the skeletal muscle is related to arterial stiffness via arterial NO production in obese rats

Follistatin‐like 1 (FSTL1), which is mainly secreted from skeletal muscle and myocardium, upregulates protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS) phosphorylation in vascular endothelial cells. It is unclear whether skeletal muscle‐ and myocardium‐derived FSTL1 secretion induced by aerobic exercise training is involved in the reduction of arterial stiffness via arterial NO production in obese rats. This study aimed to clarify whether aerobic exercise training‐induced FSTL1 secretion in myocardium and skeletal muscle is associated with a reduction in arterial stiffness via arterial Akt‐eNOS signaling pathway in obese rats. Sixteen Otsuka Long‐Evans Tokushima Fatty (OLETF) obese rats were randomly divided into two groups: sedentary control (OLETF‐CON) and eight‐week aerobic exercise training (treadmill for 60min at 25m/min, 5days/week, OLETF‐AT). Eight Long‐Evans Tokushima Otsuka (LETO) rats were used as a healthy sedentary control group. In OLETF‐CON, serum FSTL1, arterial Akt and eNOS phosphorylation, and arterial nitrite/nitrate (NOx) levels were significantly lower, and carotid‐femoral pulse wave velocity (cfPWV) was significantly greater than those in LETO. These parameters were improved in the OLETF‐AT compared to the OLETF‐CON. In the OLETF‐AT, FSTL1 levels in slow‐twitch fiber‐rich soleus muscle were significantly greater than those in the OLETF‐CON, but not in myocardium, fast‐twitch fiber‐rich tibialis anterior muscle, and adipose tissue. Serum FSTL1 levels were positively correlated with soleus FSTL1, arterial eNOS phosphorylation, and NOx levels and negatively correlated with cfPWV. Thus, aerobic exercise training‐induced FSTL1 secretion in slow‐twitch fiber‐rich muscles may be associated with a reduction in arterial stiffness via arterial NO production in obese rats.

Chlorella pyrenoidosa Polysaccharides as a Prebiotic to Modulate Gut Microbiota: Physicochemical Properties and Fermentation Characteristics In Vitro

This study was conducted to investigate the prebiotic potential of Chlorella pyrenoidosa polysaccharides to provide useful information for developing C. pyrenoidosa as a green healthy food. C. pyrenoidosa polysaccharides were prepared and their physicochemical characteristics were determined. The digestibility and fermentation characteristics of C. pyrenoidosa polysaccharides were evaluated using in vitro models. The results revealed that C. pyrenoidosa polysaccharides were composed of five non-starch polysaccharide fractions with monosaccharide compositions of Man, Rib, Rha, GlcA, Glc, Gal, Xyl and Ara. C. pyrenoidosa polysaccharides could not be degraded under saliva and the gastrointestinal conditions. However, the molecular weight and contents of residual carbohydrates and reducing sugars of C. pyrenoidosa polysaccharides were significantly reduced after fecal fermentation at a moderate speed. Notably, C. pyrenoidosa polysaccharides could remarkably modulate gut microbiota, including the promotion of beneficial bacteria, inhibition of growth of harmful bacteria, and reduction of the ratio of Firmicutes to Bacteroidetes. Intriguingly, C. pyrenoidosa polysaccharides can promote growth of Parabacteroides distasonis and increase short-chain fatty acid contents, thereby probably contributing to the promotion of intestinal health and prevention of diseases. Thus, these results suggested that C. pyrenoidosa polysaccharides had prebiotic functions with different fermentation characteristics compared with conventional prebiotics such as fructooligosaccharide, and they may be a new prebiotic for improving human health.

Decoding the chemical composition and pharmacological mechanisms of Jiedu Tongluo Tiaogan Formula using high-performance liquid chromatography coupled with network pharmacology-based investigation

Type 2 diabetes mellitus (T2DM), a chronic low-grade inflammatory disease with high morbidity and mortality, is a serious threat to public health. Previously we demonstrated that a traditional Chinese medicine formulation, Jiedu Tongluo Tiaogan Formula (JDTL), exerted a favorable hypoglycemic effect due to unknown molecular mechanisms involving interactions among JDTL compounds and various cellular components. This study aimed to explore JDTL mechanisms for alleviating hyperglycemia using an integrated strategy incorporating system pharmacology, bioinformatics analysis, and experimental verification. This strategy entailed initial elucidation of JDTL chemical composition using fingerprint analysis via high performance liquid chromatography (HPLC). Next, functions of putative shared target genes and associated pathways were deduced using GO and KEGG pathway enrichment and molecular docking analyses. Ultimately, targets associated with JTDL anti-T2DM effects were found to be functionally associated with biological functions related to lipopolysaccharide and cytokine receptor binding. These results implicated PI3K-Akt signaling pathway involvement in JDTL anti-T2DM effects, as this pathway had been previously shown to play significant roles in glucose and lipid metabolism-related diseases. Furthermore, addition of JDTL to INS-1 and HepG2 cell cultures stimulated cellular mRNA-level and protein-level expression leading to enhanced production of IRS1, Akt, and PI3K. In summary, here JDTL bioactive ingredients, potential targets, and molecular mechanisms underlying JDTL anti-T2DM effects were identified using a multi-component, multi-target, and multi-channel analytical approach, thus providing an important scientific foundation to facilitate development of new drugs mechanistic strategies for preventing and treating T2DM.

Chlorella vulgaris in combination with high intensity interval training in overweight and obese women: a randomized double-blind clinical trial

Background

Chlorella vulgaris (CV) as a multifunctional dietary supplement is known with lots of health benefits. It is possible that CV consumption along with high-intensity interval training (HIIT), a short period exercise is more beneficial. This investigation aimed to evaluate the effects of CV and/or HIIT on anthropometric parameters and cardiometabolic risk factors among overweight or obese women.

Methods

Present randomized double-blind clinical trial, included 46 women with overweight or obesity and randomly assigned them to four groups including CV, HIIT, CV+HIIT, and placebo. CV supplementation was 900 mg a day and HIIT program 3 sessions a week. Dietary intake, anthropometric assays and blood samples were taken at the commencement and completion of 8-week intervention.

Results

After 8 weeks, waist circumference (WC) significantly reduced in CV+HIIT group in comparison with placebo group. Significant decreases in triglycerides (TG) and low-density lipoprotein (LDL) cholesterol levels were found after CV supplementation and/or HIIT exercise in comparison with placebo group. A significant rise in high-density lipoprotein (HDL) cholesterol level was observed in HIIT and HIIT + CV groups in comparison with placebo group, however CV consumption failed to affect HDL cholesterol levels. CV and/or HIIT significantly lowered, visceral adiposity index (VAI), lipid accumulating product (LAP) and atherogenic index of plasma (AIP) in comparison with placebo. However, concurrent administration of CV and HII resulted in greater reduction in this indexes. Among glycemic indices a significant reduction in insulin resistance in CV+HIIT group compared with placebo group were seen.

Conclusions

In conclusion, CV and HIIT could improve lipid profile and glycemic status in overweight and obese women.

Decreased muscle-derived musclin by chronic resistance exercise is associated with improved insulin resistance in rats with type 2 diabetes

Chronic resistance exercise induces improved hyperglycemia in patients with type 2 diabetes mellitus. Musclin, a muscle‐derived secretory factor, is involved in the induction of insulin resistance via the downregulation of the glucose transporter‐4 (GLUT‐4) signaling pathway in skeletal muscles. However, whether musclin affects the mechanism of resistance exercise remains unclear. This study aimed to clarify whether decreased muscle‐derived musclin secretion in chronic resistance exercise is involved in the improvement of insulin resistance via the GLUT‐4 signaling pathway in rats with type 2 diabetes. Male, 20‐week‐old, Otsuka Long‐Evans Tokushima Fatty (OLETF) rats, a type 2 diabetes model, were randomly divided into two groups: sedentary control (OLETF‐Con) and chronic resistance exercise (OLETF‐RT; climbing a ladder three times a week on alternate days for 8 weeks), whereas Long‐Evans Tokushima Otsuka rats were used as the nondiabetic sedentary control group. OLETF‐Con rats showed increased fasting glucose levels, decreased insulin sensitivity index (QUICKI), muscle GLUT‐4 translocation, and protein kinase B (Akt) phosphorylation, and concomitantly increased muscle musclin expression. In contrast, OLETF‐RT rats significantly reduced muscle musclin expression, improved hyperglycemia, and QUICKI through an accelerated muscle GLUT‐4/Akt signaling pathway. Moreover, chronic resistance exercise‐induced reduction of muscle musclin was correlated with changes in fasting glucose, QUICKI, GLUT‐4 translocation, and Akt phosphorylation. These findings suggest that the reduction in muscle‐derived musclin production by chronic resistance exercise may be involved in improved insulin resistance in rats with type 2 diabetes.

Effects of combined exercise training and Chlorella intake on vasorelaxation mediated by nitric oxide in aged mice

Chronic Chlorella intake and aerobic exercise training reduce arterial stiffness and increase circulating nitric oxide (NO) levels, which has beneficial effects. This study aimed to clarify the combined aortic NO-mediated effects of chronic Chlorella intake and aerobic exercise training on endothelial vasorelaxation in aged mice. In this study, 38-week-old male senescence-accelerated mouse prone 1 (SAMP1) mice were divided into aged sedentary control (Con), aerobic exercise training (AT; voluntary wheel running for 12 weeks), Chlorella intake (CH; 0.5% Chlorella powder in normal diet), and AT and CH combined (AT+CH) groups. Endothelium-dependent vasorelaxation by addition of acetylcholine to the isolated mouse aortic rings was significantly higher in the AT, CH, and AT+CH groups than in the Con group; a significantly greater effect was seen in the AT+CH group than in the AT and CH groups. Similarly, plasma and arterial nitrite/nitrate levels and arterial endothelial NO synthase phosphorylation were significantly higher in the AT, CH, and AT+CH groups than in the Con group; the AT+CH group had higher values than the AT and CH groups. Thus, chronic Chlorella intake combined with aerobic exercise training had pronounced effects on endothelial vasorelaxation in aged mice via an additive increase in arterial NO production. Novelty: Endothelium-dependent vasorelaxation was improved by Chlorella intake and exercise. Chlorella intake and exercise increased arterial Akt/eNOS/NO signaling. This combination approach further improved vasorelaxation via arterial NO production.

Breeding of high protein Chlorella sorokiniana using protoplast fusion

To improve Chlorella's economic viability as a natural bait in aquaculture, protoplast fusion technology was used for two Chlorella mutants, H10 and Z13, selected by UV and chemical mutagenesis. Chlorella sorokiniana protoplast was prepared using the enzyme method, and then the optimal enzyme combination of 4% cellulase and 2% driselase was screened out. Z13 and H10 protoplast preparation rates reached 34.72% and 31.11%, respectively. Nine fusions with higher growth rates were selected to assess their biomass, total and soluble proteins contents. Dry cell weight, total protein, and soluble protein of fusion R7 were 0.92 g.L^-1, 67.16%, and 0.59 mg.g^-1, respectively. The biomass was 1.59, 1.43 times that of H10 and Z13; total and soluble proteins increased by 8.89%, 10.25% and 50.12%, 74.62% respectively, compared with the original algae. These results have implications for breeding excellent strains, and for large-scale and optimal application of Chlorella in aquaculture.

Potential of Chlorella as a Dietary Supplement to Promote Human Health

Chlorella is a green unicellular alga that is commercially produced and distributed worldwide as a dietary supplement. Chlorella products contain numerous nutrients and vitamins, including D and B12, that are absent in plant-derived food sources. Chlorella contains larger amounts of folate and iron than other plant-derived foods. Chlorella supplementation to mammals, including humans, has been reported to exhibit various pharmacological activities, including immunomodulatory, antioxidant, antidiabetic, antihypertensive, and antihyperlipidemic activities. Meta-analysis on the effects of Chlorella supplementation on cardiovascular risk factors have suggested that it improves total cholesterol levels, low-density lipoprotein cholesterol levels, systolic blood pressure, diastolic blood pressure, and fasting blood glucose levels but not triglycerides and high-density lipoprotein cholesterol levels. These beneficial effects of Chlorella might be due to synergism between multiple nutrient and antioxidant compounds. However, information regarding the bioactive compounds in Chlorella is limited.