The soy isoflavone genistein blunts nuclear factor kappa-B, MAPKs and TNF-α activation and ameliorates muscle function and morphology in mdx mice

Soy Food Consumption Is Inversely Associated with Handgrip Strength: Results from the TCLSIH Cohort Study

Background: Soy foods contain high levels of soy protein or isoflavones, which can stimulate muscle protein synthesis and increase antioxidant capacity, and thus ameliorate muscle strength decline. However, data from epidemiological studies investigating the association of habitual soy food consumption with muscle strength decline among general Chinese adults are limited. Methods: This study included 29,525 participants (mean age: 41.6 years; 16,933 (53.8%) males). Soy food consumption was evaluated using a validated 100-item food frequency questionnaire. Handgrip strength (HGS) was assessed with a hand dynamometer. Analysis of covariance were performed to assess the multivariable-adjusted least square means (LSM) and 95% confidence interval (CI) for HGS. Results: The multiple adjusted LSM (95% CI) of HGS across soy food consumption were 35.5 (34.2, 37.1) kg for <1 time per week, 36.1 (34.6, 37.6) kg for 1 time per week, 36.3 (34.8, 37.8) kg for 2−3 times per week, and 36.6 (35.1, 38.0) kg for ≥4 times per week (p for trend < 0.001). Compared to participants with soy food consumption less than one time per week, the multiple adjusted odds ratio (95% CI) of low HGS was 0.638 (0.485, 0.836) when the weekly consumption was ≥ 4 times (p for trend < 0.01). Conclusions: Higher habitual soy food consumption was positively associated with HGS in general Chinese adults. Consumption of soy foods may have beneficial effects on muscle health.

Potential Nutrients from Natural and Synthetic Sources Targeting Inflammaging-A Review of Literature, Clinical Data and Patents

Inflammaging, the steady development of the inflammatory state over age is an attributable characteristic of aging that potentiates the initiation of pathogenesis in many age-related disorders (ARDs) including neurodegenerative diseases, arthritis, cancer, atherosclerosis, type 2 diabetes, and osteoporosis. Inflammaging is characterized by subclinical chronic, low grade, steady inflammatory states and is considered a crucial underlying cause behind the high mortality and morbidity rate associated with ARDs. Although a coherent set of studies detailed the underlying pathomechanisms of inflammaging, the potential benefits from non-toxic nutrients from natural and synthetic sources in modulating or delaying inflammaging processes was not discussed. In this review, the available literature and recent updates of natural and synthetic nutrients that help in controlling inflammaging process was explored. Also, we discussed the clinical trial reports and patent claims on potential nutrients demonstrating therapeutic benefits in controlling inflammaging and inflammation-associated ARDs.

Nutraceuticals in the Prevention and Treatment of the Muscle Atrophy

Imbalance of protein homeostasis, with excessive protein degradation compared with protein synthesis, leads to the development of muscle atrophy resulting in a decrease in muscle mass and consequent muscle weakness and disability. Potential triggers of muscle atrophy include inflammation, malnutrition, aging, cancer, and an unhealthy lifestyle such as sedentariness and high fat diet. Nutraceuticals with preventive and therapeutic effects against muscle atrophy have recently received increasing attention since they are potentially more suitable for long-term use. The implementation of nutraceutical intervention might aid in the development and design of precision medicine strategies to reduce the burden of muscle atrophy. In this review, we will summarize the current knowledge on the importance of nutraceuticals in the prevention of skeletal muscle mass loss and recovery of muscle function. We also highlight the cellular and molecular mechanisms of these nutraceuticals and their possible pharmacological use, which is of great importance for the prevention and treatment of muscle atrophy.

β-Glucans as Dietary Supplement to Improve Locomotion and Mitochondrial Respiration in a Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular childhood disorder that causes progressive muscle weakness and degeneration. A lack of dystrophin in DMD leads to inflammatory response, autophagic dysregulation, and oxidative stress in skeletal muscle fibers that play a key role in the progression of the pathology. β-glucans can modulate immune function by modifying the phagocytic activity of immunocompetent cells, notably macrophages. Mitochondrial function is also involved in an important mechanism of the innate and adaptive immune responses, owing to high need for energy of immune cells. In the present study, the effects of 1,3-1,6 β-glucans on five-day-old non-dystrophic and dystrophic (sapje) zebrafish larvae were investigated. The effects of the sonication of β-glucans and the dechorionation of embryos were also evaluated. The results showed that the incidence of dystrophic phenotypes was reduced when dystrophic embryos were exposed to 2 and 4 mg L^-1 of 1,3-1,6 β-glucans. Moreover, when the dystrophic larvae underwent 8 mg L^-1 treatment, an improvement of the locomotor performances and mitochondrial respiration were observed. In conclusion, the observed results demonstrated that 1,3-1,6 β-glucans improve locomotor performances and mitochondrial function in dystrophic zebrafish. Therefore, for ameliorating their life quality, 1,3-1,6 β-glucans look like a promising diet supplement for DMD patients, even though further investigations are required.

Nutraceutical Screening in a Zebrafish Model of Muscular Dystrophy: Gingerol as a Possible Food Aid

Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin gene, is an inherited neuromuscular disorder that causes loss of muscle mass and motor skills. In the era of genomic medicine, there is still no known cure for DMD. In clinical practice, there is a growing awareness of the possible importance of nutrition in neuromuscular diseases. This is mostly the result of patients’ or caregivers’ empirical reports of how active substances derived from food have led to improved muscle strength and, thus, better quality of life. In this report, we investigate several nutraceutical principles in the sapje strain of zebrafish, a validated model of DMD, in order to identify possible natural products that, if supplemented in the diet, might improve the quality of life of DMD patients. Gingerol, a constituent of fresh ginger, statistically increased the locomotion of mutant larvae and upregulated the expression of heme oxygenase 1, a target gene for therapy aimed at improving dystrophic symptoms. Although three other compounds showed a partial positive effect on locomotor and muscle structure phenotypes, our nutraceutical screening study lent preliminary support to the efficacy and safety only of gingerol. Gingerol could easily be proposed as a dietary supplement in DMD.

A Phase 1/2 Study of Flavocoxid, an Oral NF-κB Inhibitor, in Duchenne Muscular Dystrophy

Flavocoxid is a blended extract containing baicalin and catechin with potent antioxidant and anti-inflammatory properties due to the inhibition of the cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) enzymes, nuclear factor-κB (NF-κB), tumor necrosis factor (TNF)-alpha, and the mitogen-activated protein kinases (MAPKs) pathways. This phase 1/2 study was designed to assess the safety and tolerability of flavocoxid in patients with Duchenne muscular dystrophy (DMD). Thirty-four patients were recruited: 17 were treated with flavocoxid at an oral dose of 250 or 500 mg, according to body weight, for one year; 17 did not receive flavocoxid and served as controls. The treatment was well tolerated and nobody dropped out. Flavocoxid induced a significant reduction in serum interleukin (IL)-1 beta and TNF-alpha only in the group of DMD boys on add-on therapy (flavocoxid added to steroids for at least six months). The decrease in IL-1 beta was higher in younger boys. The serum H₂O₂ concentrations significantly decreased in patients treated with flavocoxid alone with a secondary reduction of serum glutathione peroxidase (GPx) levels, especially in younger boys. The exploratory outcome measures failed to show significant effects but there was a trend showing that the younger boys who received treatment were faster at performing the Gowers' maneuver, while the older boys who received treatment were faster at doing the 10-m walk test (10MWT). Therefore, a double-blind, placebo-controlled study for at least two/three years is warranted to verify flavocoxid as a steroid substitute or as add-on therapy to steroids.

Flavonoids: nutraceutical potential for counteracting muscle atrophy

Skeletal muscle plays a vital role in the conversion of chemical energy into physical force. Muscle atrophy, characterized by a reduction in muscle mass, is a symptom of chronic disease (cachexia), aging (sarcopenia), and muscle disuse (inactivity). To date, several trials have been conducted to prevent and inhibit muscle atrophy development; however, few interventions are currently available for muscle atrophy. Recently, food ingredients, plant extracts, and phytochemicals have received attention as treatment sources to prevent muscle wasting. Flavonoids are bioactive polyphenol compounds found in foods and plants. They possess diverse biological activities, including anti-obesity, anti-diabetes, anti-cancer, anti-oxidation, and anti-inflammation. The effects of flavonoids on muscle atrophy have been investigated by monitoring molecular mechanisms involved in protein turnover, mitochondrial activity, and myogenesis. This review summarizes the reported effects of flavonoids on sarcopenia, cachexia, and disuse muscle atrophy, thus, providing an insight into the understanding of the associated molecular mechanisms.

Phytochemicals against TNFα-Mediated Neuroinflammatory Diseases

Tumor necrosis factor-alpha (TNF-α) is a well-known pro-inflammatory cytokine responsible for the modulation of the immune system. TNF-α plays a critical role in almost every type of inflammatory disorder, including central nervous system (CNS) diseases. Although TNF-α is a well-studied component of inflammatory responses, its functioning in diverse cell types is still unclear. TNF-α functions through its two main receptors: tumor necrosis factor receptor 1 and 2 (TNFR1, TNFR2), also known as p55 and p75, respectively. Normally, the functions of soluble TNF-α-induced TNFR1 activation are reported to be pro-inflammatory and apoptotic. While TNF-α mediated TNFR2 activation has a dual role. Several synthetic drugs used as inhibitors of TNF-α for diverse inflammatory diseases possess serious adverse effects, which make patients and researchers turn their focus toward natural medicines, phytochemicals in particular. Phytochemicals targeting TNF-α can significantly improve disease conditions involving TNF-α with fewer side effects. Here, we reviewed known TNF-α inhibitors, as well as lately studied phytochemicals, with a role in inhibiting TNF-α itself, and TNF-α-mediated signaling in inflammatory diseases focusing mainly on CNS disorders.

In vivo anti-inflammatory efficacy of the combined Bowman-Birk trypsin inhibitor and genistein isoflavone, two biological compounds from soybean

Soybean Bowman-Birk protease inhibitor (BBI) and genistein, two biological compounds from soybean, are well-known for their anti-inflammatory, antioxidant, and anticancer activities. The aim of this study was designing a BBI-genistein conjugate and then investigating its protective effect on lipopolysaccharide (LPS)-induced inflammation in BALB/c mice, compared with the effects of combination of BBI and genistein. BBI was purified from soybean and the BBI-genistein conjugate was synthesized. The BALB/c mice were intraperitoneally treated 2 hours before LPS induction. Our results showed that treatment with the combination of BBI and genistein greatly led to more reduced serum levels of tumor necrosis factor (TNF)-α and interferon (IFN)-γ compared with the treatments of BBI alone, the BBI-genistein conjugate, and genistein alone, respectively. Moreover, the expression of TNF-α and IFN-γ in the splenocytes was significantly downregulated along with improving host survival against the LPS-induced lethal endotoxemia in the same way. Our data support a new combined therapy using BBI and genistein, as natural anti-inflammatory agents, to develop a new drug for inflammatory diseases.

Natural constituents from food sources: potential therapeutic agents against muscle wasting

Skeletal muscle wasting is highly correlated with not only reduced quality of life but also higher morbidity and mortality. Although an increasing number of patients are suffering from various kinds of muscle atrophy and weakness, there is still no effective therapy available, and skeletal muscle is considered as an under-medicated organ. Food provided not only essential macronutrients but also functional substances involved in the modulation of the physiological systems of our body. Natural constituents from commonly consumed dietary plants, either extracts or compounds, have attracted more and more attention to be developed as agents for preventing and treating muscle wasting due to their safety and effectiveness, as well as structural diversity. This review provides an overview of the mechanistic aspects of muscle wasting, and summarizes the extracts and compounds from food sources as potential therapeutic agents against muscle wasting.

Effect of Soybean Isoflavones on Growth Performance, Immune Function, and Viral Protein 5 mRNA Expression in Broiler Chickens Challenged with Infectious Bursal Disease Virus

A total of 200 one-day-old male broilers were assigned to five groups, and each group consisted of four replicates with 10 birds per replicate. Chicks were fed the basal diet with 0 (non-infected control), 0 (infected control), 10, 20, and 40 mg/kg soybean isoflavones (SI) for 42 days. At 21 days of age, chickens were inoculated with an infectious bursal dose (causing 50% morbidity) of the infectious bursal disease virus (IBDV) BC 6/85 strain by the eye-drop and nasal route (except for the non-infected group). Average daily gain (ADG) and average daily feed intake (ADFI) decreased (p < 0.05) in broilers infected with infectious bursal disease virus (IBDV) from 22 to 42 days. However, infected broilers fed 10 and 20 mg SI/kg had the maximum (p <0.05) ADG and ADFI from 1 to 42 days. Body weight (BW) increased (p < 0.05) in infected broilers fed the 10 and 20 mg SI /kg diet. The bursa weight at 7 days post-infection (dpi) was increased (p < 0.05) by the supplemental 10 mg SI/kg diet. Infected broilers showed the highest (p < 0.05) bursa lesions, with an average score of 4.0 ± 0.0, while the severity of bursa lesions was decreased (p < 0.05) at 3 dpi and 7 dpi by the supplemental 20 mg SI/kg diet. Supplemental SI at 20 mg/kg decreased (p < 0.05) the viral protein 5 (VP5) mRNA expression at 3 dpi and 7 dpi. The level of interferon gamma (IFNγ) was elevated (p < 0.05) in the infected group at 3 dpi and 7 dpi as compared with the control group, while its level was decreased (p < 0.05) by supplemental 10 mg/kg SI at 3 dpi. The level of nuclear factor κB in the bursal tissue showed the lowest value (p < 0.05) with supplemental 10 and 20 mg SI/kg diet at 7 dpi. Supplemental 10, 20, 40 mg/kg SI improved (p < 0.05) the serum total antioxidant activity (T-AOC) in infected broilers at 3 dpi. In addition, the serum level of malondialdehyde (MDA) decreased (p < 0.05) in the group fed 20 mg/kg SI at 7 dpi. In conclusion, supplemental 10~20 mg/kg SI may have a positive effect on broiler chickens infected with IBDV, probably because SI decrease the severity of bursa lesions and viral protein 5 mRNA expression, and have strong antioxidant activity.

Genetic neuromuscular disorders: living the era of a therapeutic revolution. Part 2: diseases of motor neuron and skeletal muscle

This is the second part of a two-part document intended to discuss recent therapeutic progresses in genetic neuromuscular disorders. The present review is for diseases of motor neuron and skeletal muscle, some of which reached recently the most innovative therapeutic approaches. Nusinersen, an SMN2 mRNA splicing modifier, was approved as first-ever therapy of spinal muscular atrophy (SMA) by FDA in 2016 and by EMA in 2017. The orally administered small-molecule risdiplam, which increases SMN protein levels similarly but also in peripheral organs, is tested in ongoing phase 2 and 3 trials. After positive results with phase 1 treatment with AAV9-SMN, the first gene therapy for SMA, a phase 3 clinical trial is ongoing. Ataluren is the first approved drug for Duchenne muscular dystrophy (DMD) patients with premature stop codon mutations and its indication has been recently extended since the age of 2 years. Exon skipping technology was and is currently tested in many phase 3 trials, and eteplirsen received a conditional approval by FDA for patients amenable to exon 51 skipping, but not by EMA. Many other compounds with different mechanisms of action are now tested in DMD by phase 2 and 3 trials, including phase 1 gene therapy. Other innovative approaches are under investigation, i.e., gene therapy in X-linked myotubular myopathy and Pompe disease, and antisense oligonucleotides in myotonic dystrophy type 1. Positive evidences are discussed about lamotrigine and ranolazine in non-dystrophic myotonias, chaperons in Pompe disease, and nucleosides in mitochondrial DNA depletion induced by thymidine kinase 2 deficiency.

Hippo signaling pathway is altered in Duchenne muscular dystrophy

Hippo signaling pathway is considered a key regulator of tissue homeostasis, cell proliferation, apoptosis and it is involved in cancer development. In skeletal muscle, YAP, a downstream target of the Hippo pathway, is an important player in myoblast proliferation, atrophy/hypertrophy regulation, and in mechano-trasduction, transferring mechanical signals into transcriptional responses. We studied components of Hippo pathway in muscle specimens from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy, limb-girdle muscular dystrophy type 2A and type 2B and healthy subjects. Only DMD muscles had decreased YAP1 protein expression, increased LATS1/2 kinase activity, low Survivin mRNA expression and high miR-21 expression. In light of our novel results, a schematic model is postulated: low levels of YOD1 caused by increased inhibition by miR-21 lead to an increase of LATS1/2 activity which in turn augments phosphorylation of YAP. Reduced amount of active YAP, which is also a target of increased miR-21, causes decreased nuclear expression of YAP-mediated target genes. Since it is known that YAP has beneficial roles in promoting tissue repair and regeneration after injury so that its activation may be therapeutically useful, our results suggest that some components of Hippo pathway could become novel therapeutic targets for DMD treatment.

Are Soy Products Effective in DMD?

INTRODUCTION:

In addition to their nutritional value, processed soy bean extracts contain several activities with potential therapeutic benefits. These include anti-oxidants, and tyrosine kinase and protease inhibitory activity. There are also anecdotal reports of health benefits of soy products in alleviating DMD symptoms.

METHODS:

Mdx mice were fed a control soy-free diet or the same diet containing either a proprietary soy preparation (Haelan 951), purified soy isoflavones, purified Bowman-Birk protease inhibitor or a combination of isoflavones and Bowman-Birk inhibitor. Mice were tested for their wire hanging ability at the start of the diet regimen and every 4 weeks until week 12 of treatment.

RESULTS AND DISCUSSION: 

The diet containing Bowman-Birk inhibitor was the only one to show a significant and sustained improvement over the 12 weeks of the study. All other dietary additions; Haelan 951, isoflavones and isoflavones with Bowman-Birk inhibitor, were not significantly different from each other or from control. The effectiveness of Bowman-Birk inhibitor in mdx mice clearly warrants further study.

Chronic dietary supplementation with soy protein improves muscle function in rats

Athletes as well as elderly or hospitalized patients use dietary protein supplementation to maintain or grow skeletal muscle. It is recognized that high quality protein is needed for muscle accretion, and can be obtained from both animal and plant-based sources. There is interest to understand whether these sources differ in their ability to maintain or stimulate muscle growth and function. In this study, baseline muscle performance was assessed in 50 adult Sprague-Dawley rats after which they were assigned to one of five semi-purified “Western” diets (n = 10/group) differing only in protein source, namely 19 kcal% protein from either milk protein isolate (MPI), whey protein isolate (WPI), soy protein isolate (SPI), soy protein concentrate (SPC) or enzyme-treated soy protein (SPE). The diets were fed for 8 weeks at which point muscle performance testing was repeated and tissues were collected for analysis. There was no significant difference in food consumption or body weights over time between the diet groups nor were there differences in terminal organ and muscle weights or in serum lipids, creatinine or myostatin. Compared with MPI-fed rats, rats fed WPI and SPC displayed a greater maximum rate of contraction using the in vivo measure of muscle performance (p<0.05) with increases ranging from 13.3–27.5% and 22.8–29.5%, respectively at 60, 80, 100 and 150 Hz. When the maximum force was normalized to body weight, SPC-fed rats displayed increased force compared to MPI (p<0.05), whereas when normalized to gastrocnemius weight, WPI-fed rats displayed increased force compared to MPI (p<0.05). There was no difference between groups using in situ muscle performance. In conclusion, soy protein consumption, in high-fat diet, resulted in muscle function comparable to whey protein and improved compared to milk protein. The benefits seen with soy or whey protein were independent of changes in muscle mass or fiber cross-sectional area.

NPS 2143, a selective calcium-sensing receptor antagonist inhibits lipopolysaccharide-induced pulmonary inflammation

NPS 2143, a novel and selective antagonist of calcium-sensing receptor (CaSR) has been reported to possess anti-inflammatory activity. In the present study, we examined the protective effect of NPS 2143 on lipopolysaccharide (LPS)-induced acute lung injury (ALI). NPS 2143 pretreatment significantly inhibited the influx of inflammatory cells and the expression of monocyte chemoattractant protein-1 (MCP-1) in the lung of mice with LPS-induced ALI. NPS 2143 decreased the levels of neutrophil elastase (NE) and protein concentration in the bronchoalveolar lavage fluid (BALF). NPS 2143 also reduced the production of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the BALF and serum. In addition, NPS 2143 attenuated the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and increased the activation of AMP-activated protein kinase (AMPK) in the lung. NPS 2143 also downregulated the activation of nuclear factor-kappa B (NF-κB) in the lung. In LPS-stimulated H292 airway epithelial cells, NPS 2143 attenuated the releases of IL-6 and MCP-1. Furthermore, NPS 2143 upregulated the activation of AMPK and downregulated the activation of NF-κB. These results suggest that NPS 2143 could be potential agent for the treatment of inflammatory diseases including ALI.

Nutraceuticals and Their Potential to Treat Duchenne Muscular Dystrophy: Separating the Credible from the Conjecture

In recent years, complementary and alternative medicine has become increasingly popular. This trend has not escaped the Duchenne Muscular Dystrophy community with one study showing that 80% of caregivers have provided their Duchenne patients with complementary and alternative medicine in conjunction with their traditional treatments. These statistics are concerning given that many supplements are taken based on purely "anecdotal" evidence. Many nutraceuticals are thought to have anti-inflammatory or anti-oxidant effects. Given that dystrophic pathology is exacerbated by inflammation and oxidative stress these nutraceuticals could have some therapeutic benefit for Duchenne Muscular Dystrophy (DMD). This review gathers and evaluates the peer-reviewed scientific studies that have used nutraceuticals in clinical or pre-clinical trials for DMD and thus separates the credible from the conjecture.

Inflammaging and Skeletal Muscle: Can Protein Intake Make a Difference?

Inflammaging is the chronic low-grade inflammatory state present in the elderly, characterized by increased systemic concentrations of proinflammatory cytokines. It has been shown that inflammaging increases the risk of pathologic conditions and age-related diseases, and that it also has been associated with increased skeletal muscle wasting, strength loss, and functional impairments. Experimental evidence suggests that the increased concentrations of proinflammatory cytokines and primary tumor necrosis factor α observed in chronic inflammation lead to protein degradation through proteasome activation and reduced skeletal muscle protein synthesis (MPS) via protein kinase B/Akt downregulation. Dairy and soy proteins contain all the essential amino acids, demonstrate sufficient absorption kinetics, and include other bioactive peptides that may offer nutritional benefits, in addition to those of stimulating MPS. Whey protein has antioxidative effects, primarily because of its ability to enhance the availability of reduced glutathione and the activity of the endogenous antioxidative enzyme system. Soy protein and isoflavone-enriched soy protein, meanwhile, may counteract chronic inflammation through regulation of the nuclear transcription factor κB signaling pathway and cytokine production. Although evidence suggests that whey protein, soy protein, and isoflavone-enriched soy proteins may be promising nutritional interventions against the oxidative stress and chronic inflammation present in pathologic conditions and aging (inflammaging), there is a lack of information about the anabolic potential of dietary protein intake and protein supplementation in elderly people with increased systemic inflammation. The antioxidative and anti-inflammatory effects, as well as the anabolic potential of protein supplementation, should be further investigated in the future with well-designed clinical trials focusing on inflammaging and its associated skeletal muscle loss.

Immune-mediated pathology in Duchenne muscular dystrophy

Immunological and inflammatory processes downstream of dystrophin deficiency as well as metabolic abnormalities, defective autophagy, and loss of regenerative capacity all contribute to muscle pathology in Duchenne muscular dystrophy (DMD). These downstream cascades offer potential avenues for pharmacological intervention. Modulating the inflammatory response and inducing immunological tolerance to de novo dystrophin expression will be critical to the success of dystrophin-replacement therapies. This Review focuses on the role of the inflammatory response in DMD pathogenesis and opportunities for clinical intervention.

Changes in calsequestrin, TNF-α, TGF-β and MyoD levels during the progression of skeletal muscle dystrophy in mdx mice: a comparative analysis of the quadriceps, diaphragm and intrinsic laryngeal muscles

In Duchenne muscular dystrophy (DMD), the search for new biomarkers to follow the evolution of the disease is of fundamental importance in the light of the evolving gene and pharmacological therapies. In addition to the lack of dystrophin, secondary events including changes in calcium levels, inflammation and fibrosis greatly contribute to DMD progression and the molecules involved in these events may represent potential biomarkers. In this study, we performed a comparative evaluation of the progression of dystrophy within muscles that are differently affected by dystrophy (diaphragm; DIA and quadriceps; QDR) or spared (intrinsic laryngeal muscles) using the mdx mice model of DMD. We assessed muscle levels of calsequestrin (calcium-related protein), tumour necrosis factor (TNF-α; pro-inflammatory cytokine), tumour growth factor (TGF-β; pro-fibrotic factor) and MyoD (muscle proliferation) vs. histopathology at early (1 and 4 months of age) and late (9 months of age) stages of dystrophy. Fibrosis was the primary feature in the DIA of mdx mice (9 months: 32% fibrosis), which was greater than in the QDR (9 months: 0.6% fibrosis). Muscle regeneration was the primary feature in the QDR (9 months: 90% of centrally nucleated fibres areas vs. 33% in the DIA). The QDR expressed higher levels of calsequestrin than the DIA. Laryngeal muscles showed normal levels of TNF-α, TGF-β and MyoD. A positive correlation between histopathology and cytokine levels was observed only in the diaphragm, suggesting that TNF-α and TGF-β serve as markers of dystrophy primarily for the diaphragm.

Modulation of neuronal nitric oxide synthase and apoptosis by the isoflavone genistein in Mdx mice

Dystrophin lack in DMD causes neuronal nitric oxide synthase (nNOS) membrane delocalization which in turn promotes functional muscle ischemia, and exacerbates muscle injury. Apoptosis and the exhaustion of muscle regenerative capacity are implicated in Duchenne muscular dystrophy (DMD) pathogenesis and therefore are relevant therapeutic targets. Genistein has been reported to have pro-proliferative effects, promoting G1/S cell phase transition through the induction of cyclin D1, and anti-apoptotic properties. We previously showed that genistein could reduce muscle necrosis and enhance regeneration with an augmented number of myogenin-positive satellite cells and myonuclei, ameliorating muscle function in mdx mice. In this study we evaluated the underlying mechanisms of genistein effect on muscle specimens of mdx and wild type mice treated for five weeks with genistein (2 mg/kg/i.p. daily) or vehicle. Western blot analysis show that genistein increased cyclin D1 and nNOS expression; and showed an antiapoptotic effect, modulating the expression of BAX and Bcl-2. Our results suggest that this isoflavone might enhance the regenerative spurt in mdx mice muscle restoring nNOS, promoting G1/S phase transition in muscle cell, and inhibiting apoptosis. Further studies with longer time treatment or using different experimental approaches are needed to better investigate the underlying mechanisms of such results.

Long-Term Therapy With Omega-3 Ameliorates Myonecrosis and Benefits Skeletal Muscle Regeneration in Mdx Mice

In Duchenne muscle dystrophy (DMD) and in the mdx mouse model of DMD, a lack of dystrophin leads to myonecrosis and cardiorespiratory failure. Several lines of evidence suggest a detrimental role of the inflammatory process in the dystrophic process. Previously, we demonstrated that short-term therapy with eicosapentaenoic acid (EPA), at early stages of disease, ameliorated dystrophy progression in the mdx mouse. In the present study, we evaluated the effects of a long-term therapy with omega-3 later in dystrophy progression. Three-month-old mdx mice received omega-3 (300 mg/kg) or vehicle by gavage for 5 months. The quadriceps and diaphragm muscles were removed and processed for histopathology and Western blot. Long-term therapy with omega-3 increased the regulatory protein MyoD and muscle regeneration and reduced markers of inflammation (TNF-α and NF-kB) in both muscles studied. The present study supports the long-term use of omega-3 at later stages of dystrophy as a promising option to be investigated in DMD clinical trials.

Low-Level Laser Therapy (LLLT) in Dystrophin-Deficient Muscle Cells: Effects on Regeneration Capacity, Inflammation Response and Oxidative Stress

The present study evaluated low-level laser therapy (LLLT) effects on some physiological pathways that may lead to muscle damage or regeneration capacity in dystrophin-deficient muscle cells of mdx mice, the experimental model of Duchenne muscular dystrophy (DMD). Primary cultures of mdx skeletal muscle cells were irradiated only one time with laser and analyzed after 24 and 48 hours. The LLLT parameter used was 830 nm wavelengths at 5 J/cm² fluence. The following groups were set up: Ctrl (untreated C57BL/10 primary muscle cells), mdx (untreated mdx primary muscle cells), mdx LA 24 (mdx primary muscle cells - LLLT irradiated and analyzed after 24 h), and mdx LA 48 (mdx primary muscle cells - LLLT irradiated and analyzed after 48 h). The mdx LA 24 and mdx LA 48 groups showed significant increase in cell proliferation, higher diameter in muscle cells and decreased MyoD levels compared to the mdx group. The mdx LA 48 group showed significant increase in Myosin Heavy Chain levels compared to the untreated mdx and mdx LA 24 groups. The mdx LA 24 and mdx LA 48 groups showed significant increase in [Ca2+]i. The mdx group showed significant increase in H2O2 production and 4-HNE levels compared to the Ctrl group and LLLT treatment reduced this increase. GSH levels and GPx, GR and SOD activities increased in the mdx group. Laser treatment reduced the GSH levels and GR and SOD activities in dystrophic muscle cells. The mdx group showed significant increase in the TNF-α and NF-κB levels, which in turn was reduced by the LLLT treatment. Together, these results suggest that the laser treatment improved regenerative capacity and decreased inflammatory response and oxidative stress in dystrophic muscle cells, indicating that LLLT could be a helpful alternative therapy to be associated with other treatment for dystrophinopathies.

Layered nanoemulsions as mucoadhesive buccal systems for controlled delivery of oral cancer therapeutics

Oral cavity and oropharyngeal cancers are considered the eighth most common cancer worldwide, with relatively poor prognosis (62% of patients surviving 5 years, after diagnosis). The aim of this study was to develop a proof-of-concept mucoadhesive lozenge/buccal tablet, as a potential platform for direct sustained delivery of therapeutic antimitotic nanomedicines. Our system would serve as an adjuvant therapy for oral cancer patients undergoing full-scale diagnostic and operative treatment plans. We utilized lipid-based nanocarriers, namely nanoemulsions (NEs), containing mixed-polyethoxylated emulsifiers and a tocopheryl moiety-enriched oil phase. Prototype NEs, loaded with the proapoptotic lipophilic drug genistein (Gen), were further processed into buccal tablet formulations. The chitosan polyelectrolyte solution overcoat rendered NE droplets cationic, by acting as a mucoadhesive interfacial NE layer. With approximate size of 110 nm, the positively charged chitosan-layered NE (+25 mV) vs negatively charged chitosan-free/primary aqueous NE (-28 mV) exhibited a controlled-release profile and effective mucoadhesion for liquid oral spray prototypes. When punch-pressed, porous NE-based buccal tablets were physically evaluated for hardness, friability, and swelling in addition to ex vivo tissue mucoadhesion force and retention time measurements. Chitosan-containing NE tablets were found equivalent to primary NE and placebo tablets in compression tests, yet significantly superior in all ex vivo adhesion and in vitro release assays (P≤0.05). Following biocompatibility screening of prototype chitosan-layered NEs, substantial anticancer activity of selected cationic Gen-loaded NE formulations, against two oropahryngeal carcinomas, was observed. The data strongly indicate the potential of such nanomucoadhesive systems as maintenance therapy for oral cancer patients awaiting surgical removal, or postresection of identified cancerous lesions.

Pharmacologic management of Duchenne muscular dystrophy: target identification and preclinical trials

Duchenne muscular dystrophy (DMD) is an X-linked human disorder in which absence of the protein dystrophin causes degeneration of skeletal and cardiac muscle. For the sake of treatment development, over and above definitive genetic and cell-based therapies, there is considerable interest in drugs that target downstream disease mechanisms. Drug candidates have typically been chosen based on the nature of pathologic lesions and presumed underlying mechanisms and then tested in animal models. Mammalian dystrophinopathies have been characterized in mice (mdx mouse) and dogs (golden retriever muscular dystrophy [GRMD]). Despite promising results in the mdx mouse, some therapies have not shown efficacy in DMD. Although the GRMD model offers a higher hurdle for translation, dogs have primarily been used to test genetic and cellular therapies where there is greater risk. Failed translation of animal studies to DMD raises questions about the propriety of methods and models used to identify drug targets and test efficacy of pharmacologic intervention. The mdx mouse and GRMD dog are genetically homologous to DMD but not necessarily analogous. Subcellular species differences are undoubtedly magnified at the whole-body level in clinical trials. This problem is compounded by disparate cultures in clinical trials and preclinical studies, pointing to a need for greater rigor and transparency in animal experiments. Molecular assays such as mRNA arrays and genome-wide association studies allow identification of genetic drug targets more closely tied to disease pathogenesis. Genes in which polymorphisms have been directly linked to DMD disease progression, as with osteopontin, are particularly attractive targets.

Selective modulation through the glucocorticoid receptor ameliorates muscle pathology in mdx mice

The over-expression of NF-κB signalling in both muscle and immune cells contribute to the pathology in dystrophic muscle. The anti-inflammatory properties of glucocorticoids, mediated predominantly through monomeric glucocorticoid receptor inhibition of transcription factors such as NF-κB (transrepression), are postulated to be an important mechanism for their beneficial effects in Duchenne muscular dystrophy. Chronic glucocorticoid therapy is associated with adverse effects on metabolism, growth, bone mineral density and the maintenance of muscle mass. These detrimental effects result from direct glucocorticoid receptor homodimer interactions with glucocorticoid response elements of the relevant genes. Compound A, a non-steroidal selective glucocorticoid receptor modulator, is capable of transrepression without transactivation. We confirm the in vitro NF-κB inhibitory activity of compound A in H-2K(b) -tsA58 mdx myoblasts and myotubes, and demonstrate improvements in disease phenotype of dystrophin deficient mdx mice. Compound A treatment in mdx mice from 18 days of post-natal age to 8 weeks of age increased the absolute and normalized forelimb and hindlimb grip strength, attenuated cathepsin-B enzyme activity (a surrogate marker for inflammation) in forelimb and hindlimb muscles, decreased serum creatine kinase levels and reduced IL-6, CCL2, IFNγ, TNF and IL-12p70 cytokine levels in gastrocnemius (GA) muscles. Compared with compound A, treatment with prednisolone, a classical glucocorticoid, in both wild-type and mdx mice was associated with reduced body weight, reduced GA, tibialis anterior and extensor digitorum longus muscle mass and shorter tibial lengths. Prednisolone increased osteopontin (Spp1) gene expression and osteopontin protein levels in the GA muscles of mdx mice and had less favourable effects on the expression of Foxo1, Foxo3, Fbxo32, Trim63, Mstn and Igf1 in GA muscles, as well as hepatic Igf1 in wild-type mice. In conclusion, selective glucocorticoid receptor modulation by compound A represents a potential therapeutic strategy to improve dystrophic pathology.

Adeno-associated virus serotype 8 (AAV8) delivery of recombinant A20 to skeletal muscle reduces pathological activation of nuclear factor (NF)-κB in muscle of mdx mice

Duchenne muscular dystrophy (DMD) is a genetic muscle disease caused by the absence of a functional dystrophin protein. Lack of dystrophin protein disrupts the dystrophin-glycoprotein complex causing muscle membrane instability and degeneration. One of the secondary manifestations resulting from lack of functional dystrophin in muscle tissue is an increased level of cytokines that recruit inflammatory cells, leading to chronic upregulation of the nuclear factor (NF)-κB. Negative regulators of the classical NF-κB pathway improve muscle health in the mdx mouse model for DMD. We have previously shown in vitro that a negative regulator of the NF-κB pathway, A20, plays a role in muscle regeneration. Here, we show that overexpression of A20 by using a muscle-specific promoter delivered with an adeno-associated virus serotype 8 (AAV8) vector to the mdx mouse decreases activation of the NF-κB pathway in skeletal muscle. Recombinant A20 expression resulted in a reduction in number of fibers with centrally placed nuclei and a reduction in the number of T cells infiltrating muscle transduced with the AAV8-A20 vector. Taken together, we conclude that overexpression of A20 in mdx skeletal muscle provides improved muscle health by reduction of chronic inflammation and muscle degeneration. These results suggest A20 is a potential therapeutic target to ameliorate symptoms of DMD.