Diphlorethohydroxycarmalol Derived from Ishige okamurae Improves Behavioral and Physiological Responses of Muscle Atrophy Induced by Dexamethasone in an In-Vivo Model

Marine-Derived Bioactive Compounds: A Promising Strategy for Ameliorating Skeletal Muscle Dysfunction in COPD

Chronic obstructive pulmonary disease (COPD) is frequently accompanied by skeletal muscle dysfunction, a critical and severe extrapulmonary complication. This dysfunction contributes to reduced exercise capacity, increased frequency of acute exacerbations, and elevated mortality, serving as an independent risk factor for poor prognosis in COPD patients. Owing to the unique physicochemical conditions of the marine environment, marine-derived bioactive compounds exhibit potent anti-inflammatory and antioxidant properties, demonstrating therapeutic potential for ameliorating COPD skeletal muscle dysfunction. This review summarizes marine-derived bioactive compounds with promising efficacy against skeletal muscle dysfunction in COPD, including polysaccharides, lipids, polyphenols, peptides, and carotenoids. The discussed compounds have shown bioactivities in promoting skeletal muscle health and suppressing muscle atrophy, thereby providing potential strategies for the prevention and treatment of COPD skeletal muscle dysfunction. These findings may expand the therapeutic strategies for managing COPD skeletal muscle dysfunction.

Aerobic plus resistance exercise attenuates skeletal muscle atrophy induced by dexamethasone through the HDAC4/FoxO3a pathway

This study aimed to investigate the underlying mechanisms by which physical exercise mitigates muscle atrophy induced by Dexamethasone (Dex). A muscle atrophy model was established in the mouse C2C12 cell line and 8-week-old mice treated with Dex, with subsequent verification of phenotype and atrogene expression. The potential benefits of combined aerobic and resistance exercise in mitigating muscle atrophy were then examined. To elucidate the involvement of Histone deacetylase 4 (HDAC4) in the protective effects of exercise against muscle loss, a combination of RT-PCR, Western blotting, immunoprecipitation, and immunofluorescence staining techniques were employed. The upregulation of HDAC4 was observed following Dex-induced muscle atrophy in vitro and in vivo. Inhibition of HDAC4 in C2C12 cells resulted in an increase in myotube diameter and fusion index, along with a decrease in the expression of Atrogin-1 and MuRF1. Treatment with Tasquinimod, an HDAC4 inhibitor, effectively prevented muscle wasting and dysfunction in mice induced by Dex. After a 6-week exercise intervention, the Dex-Exercise group exhibited significant improvements in body fat level, hyperinsulinemia, muscle mass and function in comparison to the Dex-Sedentary group. Mechanistically, we discovered that HDAC4 bound to and deacetylated Forkhead box protein O 3a (FoxO3a) within the nucleus, leading to decreased phosphorylation of FoxO3a at Ser 253. This interaction subsequently facilitated the expression of downstream atrogene Atrogin-1 and MuRF1, resulting in muscle atrophy. Conversely, exercise was found to potentially mitigate muscle atrophy by inhibiting the HDAC4/FoxO3a pathway. These findings suggest that HDAC4 may be a potential therapeutic target for exercise to combat Dex-induced muscle atrophy.

A Combination Study of Pre- and Clinical Trial: Seaweed Consumption Reduces Aging-Associated Muscle Loss!

Seaweed consumption in Asian food cultures may benefit longevity and age-related conditions like sarcopenia with aging. However, sarcopenia lacks a definitive treatment, and pharmaceutical options have limitations in efficacy and safety. Recent studies on aging female mice found that Ishige okamurae (IO), a brown algae, and its active compound diphloroethohydroxycarmalol improved sarcopenia. Further research is needed to understand the effects of seaweed consumption on sarcopenia in humans. This clinical trial divided participants into a test group (receiving 500 mg/kg IO supplementation, mean±SD; age 62.73±7.18 years, n=40) and a control group (age 63.10±7.06 years, n=40). Hazard analysis assessed vital signs and muscle strength improvement during the trial. Additionally, 12-month-old mice were oral-fed IO at different doses (50, 100, 200 mg/kg) for 6-weeks. Aging and muscle-wasting related markers were evaluated, including grip strength, body weight and compositions, serum-parameters, and molecular-changes. The clinical trial found no significant changes in toxicity-parameters between the groups (p>0.05) after 12-weeks of IO supplementation. The IO group exhibited a remarkable increase in lower-limb quadriceps muscle-strength compared to the control (p=0.002). Furthermore, IO treatment improved age-related decline in quadriceps strength in the subgroup; under 61-years-old (p=0.004), without significant differences in foot-dominancy between groups (p=0.171). In 12-month-old male mice, IO administration improved age-related deficiencies in grip strength (p<0.0001) and testosterone (p=0.0001). Muscular regeneration parameters, such as lean-mass (p<0.0001), inhibition of proteolysis (measured by changes in myogenin and atrogin-1 protein expressions), cross-sectional myofiber area (p<0.0001), number of satellite cells (p=0.0001), and increased mitochondrial oxidative phosphorylation complexes in muscle tissue indicative of mitochondrial biogenesis, were also improved by IO administration. This trial is the first to explore the positive association between consuming brown-algae IO and age-related decreases in muscle strength. IO treatment helps maintain muscle mass and delays muscle wasting during aging, suggesting it as a potent nutritional strategy to protect against aging-associated sarcopenia.

Modulating glucocorticoid receptor actions in physiology and pathology: Insights from coregulators

Glucocorticoids (GCs) are a class of steroid hormones that regulate key physiological processes such as metabolism, immune function, and stress responses. The effects of GCs are mediated by the glucocorticoid receptor (GR), a ligand-dependent transcription factor that activates or represses the expression of hundreds to thousands of genes in a tissue- and physiological state-specific manner. The activity of GR is modulated by numerous coregulator proteins that interact with GR in response to different stimuli assembling into a multitude of DNA-protein complexes and facilitate the integration of these signals, helping GR to communicate with basal transcriptional machinery and chromatin. Here, we provide a brief overview of the physiological and molecular functions of GR, and discuss the roles of GR coregulators in the immune system, key metabolic tissues and the central nervous system. We also present an analysis of the GR interactome in different cells and tissues, which suggests tissue-specific utilization of GR coregulators, despite widespread functions shared by some of them.

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.

Reversibility of sarcopenia by Ishige okamurae and its active derivative diphloroethohydroxycarmalol in female aging mice

With the rapid increase in the elderly population worldwide, the number of people with sarcopenia has also increased significantly, and this disease is emerging as a medical and social issue. The development of pharmaceutics targeting sarcopenia is limited owing to the occurrence of side effects, and exercise therapy also has a limited scope of application. Therefore, it is necessary to develop safe and biocompatible agents to treat age-related sarcopenia. Ishige okamurae (IO), an edible brown alga, and its active substance, diphloroethohydroxycarmalol (DPHC), have been reported to have various physiological functions, including skeletal muscle regeneration ability. However, this effect has not been verified in an in vivo aging model. As an aging model, the oral IO extracts and DPHC supplemented 14-month-old female C57BL/6J mice were compared to the young group in this study; the mice model showed a substantial restoration of physical exercise ability with the imbalance of famine hormone and senescence-associated secretary phenotypes compared with those in young mice. Regarding the lean mass increase in aging mice following IO extract and DPHC administration, the muscular characteristics and molecular alterations in the gastrocnemius and soleus muscles, which are sensitive to the damage that occurs during the aging process, were significantly improved. Collectively, the current study reveals that the natural agent IO extract and its derivative DPHC can reverse sarcopenia that occurs during the process of aging by improving the imbalance of muscle regeneration in vivo.

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

The in vitro capacity of Ishige okamurae extract (IO) to improve impaired muscle function has been previously examined. However, the mechanism underlying IO-mediated muscle protein metabolism and the role of its component, Ishophloroglucin A (IPA), in mice with dexamethasone (Dexa)-induced muscle atrophy remains unknown. In the present study, we evaluated the effect of IO and IPA supplementation on Dexa-induced muscle atrophy by assessing muscle protein metabolism in gastrocnemius and soleus muscles of mice. IO and IPA supplementation improved the Dexa-induced decrease in muscle weight and width, leading to enhanced grip strength. In addition, IO and IPA supplementation regulated impaired protein synthesis (PI3K and Akt) or degradation (muscle-specific ubiquitin ligase muscle RING finger and atrogin-1) by modulating mRNA levels in gastrocnemius and soleus muscles. Additionally, IO and IPA upregulated mRNA levels associated with muscle growth activation (transient receptor potential vanilloid type 4 and adenosine A1 receptor) or inhibition (myostatin and sirtuin 1) in gastrocnemius and soleus muscle tissues of Dexa-induced mice. Collectively, these results suggest that IO and IO-derived IPA can regulate muscle growth through muscle protein metabolism in Dexa-induced muscle atrophy.