Urolithin B, a newly identified regulator of skeletal muscle mass.

BACKGROUND: The control of muscle size is an essential feature of health. Indeed, skeletal muscle atrophy leads to reduced strength, poor quality of life, and metabolic disturbances. Consequently, strategies aiming to attenuate muscle wasting and to promote muscle growth during various (pathological) physiological states like sarcopenia, immobilization, malnutrition, or cachexia are needed to address this extensive health issue. In this study, we tested the effects of urolithin B, an ellagitannin-derived metabolite, on skeletal muscle growth. METHODS: C2C12 myotubes were treated with 15 µM of urolithin B for 24 h. For in vivo experiments, mice were implanted with mini-osmotic pumps delivering continuously 10 µg/day of urolithin B during 28 days. Muscle atrophy was studied in mice with a sciatic nerve denervation receiving urolithin B by the same way. RESULTS: Our experiments reveal that urolithin B enhances the growth and differentiation of C2C12 myotubes by increasing protein synthesis and repressing the ubiquitin-proteasome pathway. Genetic and pharmacological arguments support an implication of the androgen receptor. Signalling analyses suggest a crosstalk between the androgen receptor and the mTORC1 pathway, possibly via AMPK. In vivo experiments confirm that urolithin B induces muscle hypertrophy in mice and reduces muscle atrophy after the sciatic nerve section. CONCLUSIONS: This study highlights the potential usefulness of urolithin B for the treatment of muscle mass loss associated with various (pathological) physiological states.

Endurance Training Attenuates Catabolic Signals Induced by TNF-α in Muscle of Mice.

PURPOSE: To determine whether endurance training attenuates the negative effects induced by an acute injection of tumor necrosis factor-α (TNF-α) in skeletal muscle of mice. METHODS: Trained (6 wk of endurance training at 60% of maximal velocity) and untrained mice were injected with TNF-α or vehicle and killed 6 h after. Tibialis anterior muscles were analyzed using Western blot and qRT-PCR for markers of inflammation and protein synthesis/degradation. RESULTS: Independently of training, TNF-α increased the mRNA of cytokines and downregulated signals linked to protein synthesis. The phosphorylation of IKKα/ß and IκBα induced by TNF-α was blunted in trained mice, suggesting altered NF-κB activation. This was associated with lower induction of several markers of protein degradation (FoxO1, MURF1, MAFbx, myostatin, Gabarapl1, and LC3BII/LC3BI ratio). CONCLUSIONS: Endurance training protects skeletal muscle against the activation of protein degradation signaling pathways induced by TNF-α.

Decrease of a specific biomarker of collagen degradation in osteoarthritis, Coll2-1, by treatment with highly bioavailable curcumin during an exploratory clinical trial.

BACKGROUND: The management of osteoarthritis (OA) remains a challenge. There is a need not only for safe and efficient treatments but also for accurate and reliable biomarkers that would help diagnosis and monitoring both disease activity and treatment efficacy. Curcumin is basically a spice that is known for its anti-inflammatory properties. In vitro studies suggest that curcumin could be beneficial for cartilage in OA. The aim of this exploratory, non-controlled clinical trial was to evaluate the effects of bio-optimized curcumin in knee OA patients on the serum levels of specific biomarkers of OA and on the evaluation of pain. METHODS: Twenty two patients with knee OA were asked to take 2x3 caps/day of bio-optimized curcumin (Flexofytol®) for 3 months. They were monitored after 7, 14, 28 and 84 days of treatment. Pain over the last 24 hours and global assessment of disease activity by the patient were evaluated using a visual analog scale (100 mm). The serum levels of Coll-2-1, Coll-2-1NO2, Fib3-1, Fib3-2, CRP, CTX-II and MPO were determined before and after 14 and 84 days of treatment. RESULTS: The treatment with curcumin was globally well tolerated. It significantly reduced the serum level of Coll2-1 (p<0.002) and tended to decrease CRP. No other significant difference was observed with the other biomarkers. In addition, curcumin significantly reduced the global assessment of disease activity by the patient. CONCLUSION: This study highlighted the potential effect of curcumin in knee OA patient. This effect was reflected by the variation of a cartilage specific biomarker, Coll2-1 that was rapidly affected by the treatment. These results are encouraging for the qualification of Coll2-1 as a biomarker for the evaluation of curcumin in OA treatment. TRIAL REGISTRATION: NCT01909037 at clinicaltrials.gov.

Trophic effect of a methanol yeast extract on 3T3 fibroblast cells.

With regard to the increase of human life expectancy, interest for topical treatments aimed to counteract skin aging is still growing. Hence, research for bioactive compounds able to stimulate skin fibroblast activity is an attractive topic. Having previously described the effects of a new methanol yeast extract on growth and metabolic activity of Saccharomyces cerevisiae, we studied its effects on 3T3 fibroblasts to evaluate its potential antiaging property. This investigation demonstrates that this extract increases proliferation as well as migration of 3T3 cells and decreases their entrance in senescence and apoptosis phases. Altogether, these results open new perspectives for the formulation of innovative antiaging topical treatments.

Curcumin: a new paradigm and therapeutic opportunity for the treatment of osteoarthritis: curcumin for osteoarthritis management.

The management of osteoarthritis represents a real challenge. This complex and multi-factorial disease evolves over decades and requires not only the alleviation of symptoms, i.e. pain and joint function but also the preservation of articular structure without side effects. Nutraceuticals are good candidates for the management of OA due to their safety profile and potential efficacy. However, they are not part of the treatment guidelines and published recommendations. Curcumin is the yellow pigment isolated from the rhizomes of Curcuma longa, commonly known as turmeric. Curcumin is a highly pleiotropic molecule with an excellent safety profile. Strong molecular evidence has been published for its potency to target multiple inflammatory diseases. However, naturally occurring curcumin cannot achieve its optimum therapeutic outcomes due to its low solubility and poor bioavailability. Nevertheless, curcumin presents great potential for treating OA and has been categorized as having preclinical evidence of efficacy. This review aimed at gathering most of the available information to document the potential efficacy of curcumin based on the results obtained in in vitro models of cartilage and osteoarthritis and in other diseases.

1,2-vinyldithiin from garlic inhibits differentiation and inflammation of human preadipocytes.

Obesity is a state of chronic low-grade inflammation. Limiting white adipose tissue (WAT) expansion and therefore reducing inflammation could be effective in preventing the progression of obesity and the development of associated complications. We investigated the effects of 1,2-vinyldithiin (1,2-DT), a garlic-derived organosulfur, on the differentiation and inflammatory state of human preadipocytes. Preadipocytes were prepared from subcutaneous adipose tissue of nonobese young women and differentiated in the presence of 1,2-DT. Inflammatory preadipocytes were obtained following treatment with human macrophage-secreted factors. 1,2-DT (100 micromol/L) significantly reduced gene expression of PPARgamma2 (-40%), CCAAT/enhancer binding protein-alpha (-25%), lipoprotein lipase (-22%), leptin (-30%), and adiponectin (-15%). Lipid accumulation was also significantly diminished in preadipocytes differentiated in the presence of 100 micromol/L 1,2-DT (-37%) compared with controls. Furthermore, 100 micromol/L 1,2-DT treatment for 10 d significantly reduced PPARgamma activity (-27%). The protein expression of perilipin and the secretion levels for 2 adipokines, leptin and adiponectin, were significantly diminished in 1,2-DT-cultured preadipocytes (-37, -51, and -43%, respectively). Moreover, the secretion of inflammatory molecules (interleukin-6 and monocyte chemoattractant protein-1) induced by macrophage-secreted factors was partially abolished in 100 micromol/L 1,2-DT-treated preadipocytes (-28 and -25%, respectively). In conclusion, we demonstrated that 1,2-DT, a garlic-derived organosulfur, has antiadipogenic and antiinflammatory actions on human preadipocytes and may be a novel, antiobesity nutraceutical.