Ishophloroglucin A, Isolated from Ishige okamurae, Alleviates Dexamethasone-Induced Muscle Atrophy through Muscle Protein Metabolism In Vivo

Protective effects of Trifuhalol A, a Phlorotannin derived from edible Brown seaweed Agarum cribrosum, on dexamethasone-induced muscle atrophy in muscle cells and zebrafish models

Muscle atrophy, characterized by declines in muscle mass and functionality, currently lacks effective therapeutic options, highlighting an urgent need for further research. This research aimed to elucidate the protective effects of Trifuhalol A (TFA), a phlorotannin derived from Agarum cribrosum, against dexamethasone (Dexa)-induced muscle atrophy in zebrafish and C2C12 cells. TFA enhanced differentiation of myoblasts and myotube formation by upregulating MyHC, myogenin, MyoD, p-Akt, and p-mTOR, as well as activation of key downstream effectors of the mTOR pathway, enhancing protein synthesis. It also inhibited key markers associated with muscle atrophy, such as FoxO3a, MuRF-1, and MAFbx. In vivo, TFA treatment prevented the Dexa-induced reduction in myofiber diameter and cross-sectional area (CSA). Zebrafish exploratory behavior tests revealed that TFA improved swimming patterns and food-tracking velocity, indicating improved swimming performance and responsiveness. In conclusion, TFA mitigates Dexa-triggered muscle atrophy, and these effects are associated with improvements in muscle morphology and swimming performance. While the underlying mechanisms remain to be fully elucidated, the observed effects may involve modulation of the Akt/mTOR/FoxO3a signaling pathway. These findings suggest that TFA holds promise as a potential functional ingredient for supporting muscle health and mitigating muscle atrophy.

Ishophloroglucin A Isolated from Ishige okamurae Protects Glomerular Cells from Methylglyoxal-Induced Diacarbonyl Stress and Inhibits the Pathogenesis of Diabetic Nephropathy

Ishige okamurae (I. okamuare), an edible brown alga, is rich in isophloroglucin A (IPA) phlorotannin compounds and is effective in preventing diseases, including diabetes. We evaluated its anti-glycation ability, intracellular reactive oxygen species scavenging activity, inhibitory effect on the accumulation of intracellular MGO/MGO-derived advanced glycation end products (AGE), and regulation of downstream signaling pathways related to the AGE-receptor for AGEs (RAGE) interaction. IPA (0.2, 1, and 5 μM) demonstrated anti-glycation ability by inhibiting the formation of glucose-fructose-BSA-derived AGEs by up to 54.63% compared to the untreated control, reducing the formation of irreversible cross-links between MGO-derived AGEs and collagen by 67.68% and the breaking down of existing cross-links by approximately 91% (p < 0.001). IPA protected cells from MGO-induced oxidative stress by inhibiting intracellular MGO accumulation (untreated cells: 1.62 μg/mL, MGO treated cells: 25.27 μg/mL, and IPA 5 μM: 11.23 μg/mL) (p < 0.001) and AGE generation and inhibited MGO-induced renal cell damage via the downregulation of MGO-induced RAGE protein expression (relative protein expression levels of MGO treated cells: 9.37 and IPA 5 μM:1.74) (p < 0.001). Overall, these results suggest that IPA has the potential to be utilized as a useful natural agent for the prevention and management of AGE-related diabetic nephropathy, owing to its strong anti-glycation activity.

Molecular mechanism of skeletal muscle loss and its prevention by natural resources

A skeletal muscle disorder has drawn attention due to the global aging issues. The loss of skeletal muscle mass has been suggested to be from the reduced muscle regeneration by dysfunction of muscle satellite cell/fibro-adipogenic progenitor cells and the muscle atrophy by dysfunction of mitochondria, ubiquitin-proteasome system, and autophagy. In this review, we highlighted the underlying mechanisms of skeletal muscle mass loss including Notch signaling, Wnt/β-catenin signaling, Hedgehog signaling, AMP-activated protein kinase (AMPK) signaling, and mammalian target of rapamycin (mTOR) signaling. In addition, we summarized accumulated studies of natural resources investigating their roles in ameliorating the loss of skeletal muscle mass and demonstrating the underlying mechanisms in vitro and in vivo. In conclusion, following the studies of natural resources exerting the preventive activity in muscle mass loss, the signaling-based approaches may accelerate the development of functional foods for sarcopenia prevention.

Aerobic Exercise Ameliorates Muscle Atrophy Induced by Methylglyoxal via Increasing Gastrocnemius and Extensor Digitorum Longus Muscle Sensitivity

Muscle atrophy is characterized by the loss of muscle function. Many efforts are being made to prevent muscle atrophy, and exercise is an important alternative. Methylglyoxal is a well-known causative agent of metabolic diseases and diabetic complications. This study aimed to evaluate whether methylglyoxal induces muscle atrophy and to evaluate the ameliorative effect of moderate-intensity aerobic exercise in a methylglyoxal-induced muscle atrophy animal model. Each mouse was randomly divided into three groups: control, methylglyoxal-treated, and methylglyoxal-treated within aerobic exercise. In the exercise group, each mouse was trained on a treadmill for 2 weeks. On the last day, all groups were evaluated for several atrophic behaviors and skeletal muscles, including the soleus, plantaris, gastrocnemius, and extensor digitorum longus were analyzed. In the exercise group, muscle mass was restored, causing in attenuation of muscle atrophy. The gastrocnemius and extensor digitorum longus muscles showed improved fiber cross-sectional area and reduced myofibrils. Further, they produced regulated atrophy-related proteins (i.e., muscle atrophy F-box, muscle RING-finger protein-1, and myosin heavy chain), indicating that aerobic exercise stimulated their muscle sensitivity to reverse skeletal muscle atrophy. In conclusion, shortness of the gastrocnemius caused by methylglyoxal may induce the dynamic imbalance of skeletal muscle atrophy, thus methylglyoxal may be a key target for treating skeletal muscle atrophy. To this end, aerobic exercise may be a powerful tool for regulating methylglyoxal-induced skeletal muscle atrophy.

Xiaotangzhike Pill Attenuates the Progression of Diabetes In Vivo through the Mediation of the Akt/GSK-3β Axis

Background

Diabetes seriously threatens the health of people. Traditional Chinese medicine has been proven to inhibit the progression of diabetes. Meanwhile, the Xiaotangzhike pill (XTZK) was known to alleviate the symptom of diabetes. Thus, this research decided to investigate the mechanism underlying the impact of XTZK in diabetes remains unexplored.

Methods

To assess the impact of XTZK in diabetes, in vivo model of diabetes was constructed. The contents of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) in the rats were tested by the commercial kits. In addition, Masson and hematoxylin and eosin (H&E) staining were applied for assessing the histological changes and fibrosis in the rats, respectively. Furthermore, a western blot was applied to assess the protein levels.

Results

Streptozotocin (STZ) significantly increased the levels of area under the curve (AUC), TG, TC, LDL-C, and decreased the contents of HDL-C in rats, while these phenomena were partially reversed by XTZK. In addition, STZ notably induced inflammatory infiltration and fibrosis in the liver tissues of rats, which was greatly restored by XTZK. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and malondialdehyde (MDA) in the serum of rats were notably upregulated by STZ, while the effect of STZ was markedly abolished by XTZK. Meanwhile, STZ-caused the upregulation of p-Smad2 and α-SMA in rats was restored by XTZK. Furthermore, XTZK notably inhibited the progression of Qi and Yin deficiency syndrome in diabetes through the mediation of the Akt/GSK-3β axis.

Conclusion

The Xiaotangzhike pill attenuates the progression of diabetes through the mediation of the Akt/GSK-3β axis. Hence, our study might supply a novel insight into discovering new strategies against diabetes.

Effect of Ishige okamurae extract on musculoskeletal biomarkers in adults with relative sarcopenia: Study protocol for a randomized double-blind placebo-controlled trial

INTRODUCTION

Sarcopenia is a phenomenon in which skeletal muscle mass decreases with age, causing many health problems. Many studies have been conducted to improve sarcopenia nutritionally. Ishige okamura (IO) is a genus of brown algae and plays a role in anti-diabetes, anti-obesity, and myogenesis. However, the effect of IO extract (IOE) on human muscle strength and mass is unclear. Therefore, we will examine the impact and safety of consumption of IOE for 12 weeks on muscle strength and mass in middle-aged and old-aged adults with relatively low skeletal muscle mass.

MATERIALS AND METHODS

A randomized controlled trial is conducted on 80 adults aged 50-80. A total of 80 participants will be enrolled in this study. Participants assign IOE-taking group (n = 40) and placebo taking group (n = 40). At a baseline and 12 weeks after treatment, the following parameters of the participants are checked: knee extension strength, handgrip strength, body composition, laboratory tests, dietary recall, physical activity, and EQ-5D-5L.

DISCUSSION

The present study will be the first randomized, double-blind placebo-controlled trial to examine the efficacy and tolerability of IOE supplementation in adults with relatively low muscle mass. The nutritional intake and physical activity that might influence muscle strength and mass will be considered as covariates for transparency of results. The results of this study will provide clinical evidence for sarcopenia patients with nutrient treatment.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov/, Identifier: NCT04617951.