Giving combined medium-chain fatty acids and glucose protects against cancer-associated skeletal muscle atrophy

Caprylic Acid Inhibits High Mobility Group Box-1-Induced Mitochondrial Damage in Myocardial Tubes

Myocardial damage significantly impacts the prognosis of patients with cancer; however, the mechanisms of myocardial damage induced by cancer and its treatment remain unknown. We previously reported that medium-chain fatty acids (MCFAs) improve cancer-induced myocardial damage but did not evaluate the differences in effect according to MCFA type. Therefore, this study investigated the role of inflammatory cytokines in cancer-induced myocardial damage and the effects of three types of MCFAs (caprylic acid [C8], capric acid [C10], and lauric acid [C12]). In a mouse model, the C8 diet showed a greater effect on improving myocardial damage compared with C10 and C12 diets. Myocardial tubes differentiated from H9C2 cardiomyoblasts demonstrated increased mitochondrial oxidative stress, decreased membrane potential and mitochondrial volume, and inhibited myocardial tube differentiation following treatment with high-mobility group box-1 (HMGB1) but not interleukin-6 and tumor necrosis factor-α cytokines. However, HMGB1 treatment combined with C8 improved HMGB1-induced mitochondrial damage, enhanced autophagy, and increased mitochondrial biogenesis and maturation. However, these effects were only partial when combined with beta-hydroxybutyrate, a C8 metabolite. Thus, HMGB1 may play an important role in cancer-related myocardial damage. C8 counteracts HMGB1's effects and improves cancer-related myocardial damage. Further clinical studies are required to investigate the effects of C8.

Differential Effects of Three Medium-Chain Fatty Acids on Mitochondrial Quality Control and Skeletal Muscle Maturation

Nutritional interventions are one focus of sarcopenia treatment. As medium-chain fatty acids (MCFAs) are oxidized in the mitochondria and produce energy through oxidative phosphorylation (OXPHOS), they are key parts of nutritional interventions. We investigated the in vitro effects of three types of MCFA, caprylic acid (C8), capric acid (C10), and lauric acid (C12), in skeletal muscle cells. Compared with C10 and C12, C8 promoted mitophagy through the phosphatase and tensin homolog (PTEN)-induced kinase 1-Parkin pathway and increased the expression of peroxisome proliferator-activated receptor gamma coactivator 1-α and dynamin-related protein 1 to reduce mitochondrial oxidative stress and promote OXPHOS. Furthermore, the expression of myogenic differentiation 1 and myosin heavy chain increased in myotubes, thus promoting muscle differentiation and maturation. These results suggest that C8 improves mitochondrial quality and promotes skeletal muscle maturation; in contrast, C10 and C12 poorly promoted mitochondrial quality control and oxidative stress and suppressed energy production. Future animal experiments are required to establish the usefulness of C8 for nutritional interventions for sarcopenia.

Cancerous Conditions Accelerate the Aging of Skeletal Muscle via Mitochondrial DNA Damage

Skeletal muscle aging and sarcopenia result in similar changes in the levels of aging markers. However, few studies have examined cancer sarcopenia from the perspective of aging. Therefore, this study investigated aging in cancer sarcopenia and explored its causes in vitro and in vivo. In mouse aging, in vitro cachexia, and mouse cachexia models, skeletal muscles showed similar changes in aging markers including oxidative stress, fibrosis, reduced muscle differentiation potential, and telomere shortening. Furthermore, examination of mitochondrial DNA from skeletal muscle revealed a 5 kb deletion in the major arc; truncation of complexes I, IV, and V in the electron transport chain; and reduced oxidative phosphorylation (OXPHOS). The mouse cachexia model demonstrated high levels of high-mobility group box-1 (HMGB1) and tumor necrosis factor-α (TNFα) in cancer ascites. Continuous administration of neutralizing antibodies against HMGB1 and TNFα in this model reduced oxidative stress and abrogated mitochondrial DNA deletion. These results suggest that in cancer sarcopenia, mitochondrial oxidative stress caused by inflammatory cytokines leads to mitochondrial DNA damage, which in turn leads to decreased OXPHOS and the promotion of aging.

Glucose loading for heart failure protects the myocardium and improves physical function

[Purpose] The purpose of this study was to investigate the effects of glucose intake on physical function in a heart failure rat model. [Materials and Methods] Five-week-old male Wistar rats were used for this study. Monocrotalin (40 mg/kg) was administered intraperitoneally to rats to induce heart failure. The rats were divided into two groups, control and MCT; the MCT group was further classified according to glucose concentration (0%, 10%, and 50%). [Results] Glucose intake during heart failure prevented the loss of body weight, skeletal muscle, and fat mass. Myocardial metabolism in heart failure was enhanced by hypoxia, which in turn, enhanced the glycolytic system. [Conclusion] Glucose loading suppressed cardiac hypertrophy and improved physical function in the heart failure rat model.

Lauric Acid Overcomes Hypoxia-Induced Gemcitabine Chemoresistance in Pancreatic Ductal Adenocarcinoma

Although gemcitabine (GEM) is widely used in chemotherapy for pancreatic ductal adenocarcinoma (PDA), drug resistance restricts its clinical effectiveness. To examine the mechanism of GEM resistance, we established two GEM-resistant cell lines from human PDA cells by continuous treatment with GEM and CoCl₂-induced chemical hypoxia. One resistant cell line possessed reduced energy production and decreased mitochondrial reactive oxygen species levels, while the other resistant cell line possessed increased stemness. In both cell lines, ethidium bromide-stained mitochondrial DNA levels decreased, suggesting mitochondrial DNA damage. Inhibition of hypoxia-inducible factor-1α in both cell lines did not restore the GEM sensitivity. In contrast, treatment of both cell types with lauric acid (LAA), a medium-chain fatty acid, restored GEM sensitivity. These results suggest that decreased energy production, decreased mitochondrial reactive oxygen species levels, and increased stemness associated with mitochondrial damage caused by GEM lead to GEM resistance, and that hypoxia may promote this process. Furthermore, forced activation of oxidative phosphorylation by LAA could be a tool to overcome GEM resistance. Clinical verification of the effectiveness of LAA in GEM resistance is necessary in the future.

A pre-column derivatization high-performance liquid chromatography method for simultaneous determination of short-chain and medium-chain fatty acids in a fecal sample

Short-chain and medium-chain fatty acids have plentiful biological functions, which play a crucial role in the diagnosis and therapy of many diseases. Herein, a new method for simultaneous quantifying 17 short-chain and medium-chain fatty acids with high-performance liquid chromatography coupled with an ultraviolet detector was developed and the pre-column derivatization by indole-3-acetic acid hydrazide was performed to improve the separation and detection. The conditions of the derivatization reaction were systematically investigated. Subsequently, the method was validated and the results showed a satisfactory linearity (linear regression coefficients > 0.9969), the limit of detection (4.0×10^-3 -1.9×10^-2 μmol/L), precision (0.9%-7.3% for intra-day and 2.0%-9.8% for inter-day), recovery (90.0%-109.1% with relative standard deviation <7.7%) and stability (0.1%-3.3% for standard solution and 0.2%-3.9% for fecal sample). Finally, the established method was successfully applied to quantify short-chain and medium-chain fatty acids in the feces of healthy control and diabetic rats. Eleven kinds of short-chain and medium-chain fatty acids were detected and six of them showed a significant difference between the control group and the model group.

L-carnitine ameliorates the muscle wasting of cancer cachexia through the AKT/FOXO3a/MaFbx axis

Background

Recent studies suggest potential benefits of applying L-carnitine in the treatment of cancer cachexia, but the precise mechanisms underlying these benefits remain unknown. This study was conducted to determine the mechanism by which L-carnitine reduces cancer cachexia.

Methods

C2C12 cells were differentiated into myotubes by growing them in DMEM for 24 h (hrs) and then changing the media to DMEM supplemented with 2% horse serum. Differentiated myotubes were treated for 2 h with TNF-α to establish a muscle atrophy cell model. After treated with L-carnitine, protein expression of MuRF1, MaFbx, FOXO3, p-FOXO3a, Akt, p-Akt, p70S6K and p-p70S6K was determined by Western blotting. Then siRNA-Akt was used to determine that L-carnitine ameliorated cancer cachexia via the Akt/FOXO3/MaFbx. In vivo, the cancer cachexia model was established by subcutaneously transplanting CT26 cells into the left flanks of the BALB/c nude mice. After treated with L-carnitine, serum levels of IL-1, IL-6 and TNF-α, and the skeletal muscle content of MuRF1, MaFbx, FOXO3, p-FOXO3a, Akt, p-Akt, p70S6K and p-p70S6K were measured.

Results

L-carnitine increased the gastrocnemius muscle (GM) weight in the CT26-bearing cachexia mouse model and the cross-sectional fiber area of the GM and myotube diameters of C2C12 cells treated with TNF-α. Additionally, L-carnitine reduced the protein expression of MuRF1, MaFbx and FOXO3a, and increased the p-FOXO3a level in vivo and in vitro. Inhibition of Akt, upstream of FOXO3a, reversed the effects of L-carnitine on the FOXO3a/MaFbx pathway and myotube diameters, without affecting FOXO3a/MuRF-1. In addition to regulating the ubiquitination of muscle proteins, L-carnitine also increased the levels of p-p70S6K and p70S6K, which are involved in protein synthesis. Akt inhibition did not reverse the effects of L-carnitine on p70S6K and p-p70S6K. Hence, L-carnitine ameliorated cancer cachexia via the Akt/FOXO3/MaFbx and p70S6K pathways. Moreover, L-carnitine reduced the serum levels of IL-1 and IL-6, factors known to induce cancer cachexia. However, there were minimal effects on TNF-α, another inducer of cachexia, in the in vivo model.

Conclusion

These results revealed a novel mechanism by which L-carnitine protects muscle cells and reduces inflammation related to cancer cachexia.

Metabolic Remodeling in Skeletal Muscle Atrophy as a Therapeutic Target

Skeletal muscle is a highly responsive tissue, able to remodel its size and metabolism in response to external demand. Muscle fibers can vary from fast glycolytic to slow oxidative, and their frequency in a specific muscle is tightly regulated by fiber maturation, innervation, or external causes. Atrophic conditions, including aging, amyotrophic lateral sclerosis, and cancer-induced cachexia, differ in the causative factors and molecular signaling leading to muscle wasting; nevertheless, all of these conditions are characterized by metabolic remodeling, which contributes to the pathological progression of muscle atrophy. Here, we discuss how changes in muscle metabolism can be used as a therapeutic target and review the evidence in support of nutritional interventions and/or physical exercise as tools for counteracting muscle wasting in atrophic conditions.

Chemical compositions and sensory characteristics of pork rib and Silkie chicken soups prepared by various cooking techniques

Meat soup is an important diet with desirable taste and abundant nutrients. Unveiling the chemical composition of soup will help to understand the health effects. In this work, pork ribs and Silkie chicken were used to prepare soups by boiling, steaming and four-stage stewing, respectively. The chemical composition and sensory qualities of these soups were obviously influenced by the cooking technique. Silkie chicken and pork rib soups prepared by four-stage stewing technique had particle size smaller than 850 nm, smaller chromatic aberration, higher stability, higher levels of free amino acids, lower levels of fat and total triglycerides than the other two techniques. More abundant flavor and taste characteristics were also detected. The high temperature boiling technique could promote the accumulation of the mineral elements in soup. According to healthy and sensory concerns, stewing was the best choice for preparing soups of pork rib and Silkie chicken.

Nutraceuticals and Exercise against Muscle Wasting during Cancer Cachexia

Cancer cachexia (CC) is a debilitating multifactorial syndrome, involving progressive deterioration and functional impairment of skeletal muscles. It affects about 80% of patients with advanced cancer and causes premature death. No causal therapy is available against CC. In the last few decades, our understanding of the mechanisms contributing to muscle wasting during cancer has markedly increased. Both inflammation and oxidative stress (OS) alter anabolic and catabolic signaling pathways mostly culminating with muscle depletion. Several preclinical studies have emphasized the beneficial roles of several classes of nutraceuticals and modes of physical exercise, but their efficacy in CC patients remains scant. The route of nutraceutical administration is critical to increase its bioavailability and achieve the desired anti-cachexia effects. Accumulating evidence suggests that a single therapy may not be enough, and a bimodal intervention (nutraceuticals plus exercise) may be a more effective treatment for CC. This review focuses on the current state of the field on the role of inflammation and OS in the pathogenesis of muscle atrophy during CC, and how nutraceuticals and physical activity may act synergistically to limit muscle wasting and dysfunction.

Evaluation of cancer-derived myocardial impairments using a mouse model

Myocardial damage in cancer patients is emphasized as a cause of death; however, there are not many murine cachexia models to evaluate cancer-derived heart disorder. Using the mouse cachexia model that we established previously, we investigated myocardial damage in tumor-bearing mice. In cachexic mice, decreased heart weight and myocardial volume, and dilated left ventricular lumen, and atrophied cardiomyocytes were noted. The cardiomyocytes also showed accumulated 8-hydroxydeoxyguanosine, decreased leucine zipper and EF-hand-containing transmembrane protein-1, and increased microtubule-associated protein light chain3-II. Levels of tumor necrosis factor-α and high-mobility group box-1 proteins in the myocardium were increased, and nuclear factor κB, a signaling molecule associated with these proteins, was activated. When rat cardiomyoblasts (H9c2 cells) were treated with mouse cachexia model ascites and subjected to flux analysis, both oxidative phosphorylation and glycolysis were suppressed, and the cells were in a quiescent state. These results are in good agreement with those previously reported on cancerous myocardial damage. The established mouse cachexia model can therefore be considered useful for analyzing cancer-derived myocardial damage.

Combined administration of lauric acid and glucose improved cancer-derived cardiac atrophy in a mouse cachexia model

Cancer‐derived myocardial damage is an important cause of death in cancer patients. However, the development of dietary interventions for treating such damage has not been advanced. Here, we investigated the effect of dietary intervention with lauric acid (LAA) and glucose, which was effective against skeletal muscle sarcopenia in a mouse cachexia model, on myocardial damage. Treatment of H9c2 rat cardiomyoblasts with lauric acid promoted mitochondrial respiration and increased ATP production by Seahorse flux analysis, but did not increase oxidative stress. Glycolysis was also promoted by LAA. In contrast, mitochondrial respiration and ATP production were suppressed, and oxidative stress was increased in an in vitro cachexia model in which cardiomyoblasts were treated with mouse cachexia ascites. Ascites‐treated H9c2 cells with concurrent treatment with LAA and high glucose showed that mitochondrial respiration and glycolysis were promoted more than that of the control, and ATP was restored to the level of the control. Oxidative stress was also reduced by the combined treatment. In the mouse cachexia model, myocardiac atrophy and decreased levels of a marker of muscle maturity, SDS‐soluble MYL1, were observed. When LAA in CE‐2 diet was orally administered alone, no significant rescue was observed in the cancer‐derived myocardial disorder. In contrast, combined oral administration of LAA and glucose recovered myocardial atrophy and MYL1 to levels observed in the control without increase in the cancer weight. Therefore, it is suggested that dietary intervention using a combination of LAA and glucose for cancer cachexia might improve cancer‐derived myocardial damage.

Evaluation of Parameters for Cancer-Induced Sarcopenia in Patients Autopsied after Death from Colorectal Cancer

Cachexia frequently occurs in cancer patients and is correlated with reduced therapeutic responsiveness and poor prognosis. Although skeletal muscle atrophy is an important factor related to cachexia, biomarkers for its early diagnosis are not yet definitive. In this study, weight loss, body mass index, skeletal muscle index (SMI), serum carcinoembryonic antigen, serum tumor necrosis factor (TNF)-α, serum interleukin (IL)-6, serum high mobility group box (HMGB)-1, and SDS-soluble myosin light chain 1 (SDS-MYL1) of the psoas muscle were examined in 8 autopsied cases of death from colorectal cancer (CRC) as biomarkers of cachexia. SDS-MYL1 was positively correlated to SMI and TNF-α was negatively correlated, but the other factors did not show any correlations with SMI. Multivariate analysis showed that of the 3 cytokines, TNF-α and HMGB1 were correlated with SMI. Furthermore, when the biochemical skeletal muscle maturation marker, SDS-MYL1, was compared with serum cytokines, TNF-α and HMGB1 were negatively correlated but IL-6 was not. In multivariate analysis, only TNF-α was associated with SDS-MYL1. A positive correlation was found between TNF-α and HMGB1. These findings suggest that since TNF-α was inversely correlated with SMI and SDS-MYL1, TNF-α is a serum marker of skeletal muscle atrophy in CRC. Moreover, SDS-MYL1 might be established as a biomarker linked to clinical sarcopenia in experiments in vitro and in vivo.

Giving combined medium-chain fatty acids and glucose protects against cancer-associated skeletal muscle atrophy

Skeletal muscle volume is associated with prognosis of cancer patients. Maintenance of skeletal muscle is an essential concern in cancer treatment. In nutritional intervention, it is important to focus on differences in metabolism between tumor and skeletal muscle. We examined the influence of oral intake of glucose (0%, 10%, 50%) and 2% medium‐chain fatty acid (lauric acid, LAA, C12:0) on tumor growth and skeletal muscle atrophy in mouse peritoneal metastasis models using CT26 mouse colon cancer cells and HT29 human colon cancer cells. After 2 weeks of experimental breeding, skeletal muscle and tumor were removed and analyzed. Glucose intake contributed to prevention of skeletal muscle atrophy in a sugar concentration‐dependent way and also promoted tumor growth. LAA ingestion elevated the level of skeletal muscle protein and suppressed tumor growth by inducing tumor‐selective oxidative stress production. When a combination of glucose and LAA was ingested, skeletal muscle mass increased and tumor growth was suppressed. Our results confirmed that although glucose is an important nutrient for the prevention of skeletal muscle atrophy, it may also foster tumor growth. However, the ingestion of LAA inhibited tumor growth, and its combination with glucose promoted skeletal muscle integrity and function, without stimulating tumor growth. These findings suggest novel strategies for the prevention of skeletal muscle atrophy.