Etudes Anti-âge

Influence de la sérine sur la sécrétion de GH et cortisol?

28/03/2018 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

Effects of L-serine supplementation on the daily rhythms of growth hormone and corticosterone concentrations in mice
Li Wu,      Biological Rhythm Research       22 Mar 2018    

The impact of L-serine on the daily rhythms of growth hormone (GH) and corticosterone remains unknown. We explored whether the daily rhythms of these hormones were affected by L-serine supplementation as well as the supplementation time.

The results showed that plasma GH concentration at Zeitgeber time (ZT) 4 and 8 were significantly increased by L-serine supplementation at ZT22, while the diurnal rhythms peaks of plasma corticosterone at ZT12 were suppressed by L-serine supplementation at ZT10. After the supplementation was stopped, the effects of L-serine on the diurnal rhythms of plasma GH and corticosterone lasted for 2 days then they were fading on day 4. L-serine concentrations in plasma and hypothalamus after supplementation at ZT22 was lower than those after supplementation at ZT10.

In conclusion, L-serine modulates the daily rhythms of GH and corticosterone depending on its supplementation time. The modulation effect might be association with the daily rhythms of L-serine metabolism.

Effet du glycérol sur le cancer du foie

24/03/2018 | Etudes Compléments alimentaires et Etudes Anti-âge

 

Attenuation of liver cancer development by oral glycerol supplementation in the rat
Alejo M. Capiglioni   European Journal of Nutrition April 2018, Volume 57, Issue 3, pp 1215–1224 | Cite as

Purpose
Glycerol usage is increasing in food industry for human and animal nutrition. This study analyzed the impact of glycerol metabolism when orally supplemented during the early stage of rat liver carcinogenesis.

Methods
Wistar rats were subjected to a 2-phase model of hepatocarcinogenesis (initiated-promoted, IP group). IP animals also received glycerol by gavage (200 mg/kg body weight, IPGly group).

Results
Glycerol treatment reduced the volume of preneoplastic lesions by decreasing the proliferative status of liver foci, increasing the expression of p53 and p21 proteins and reducing the expression of cyclin D1 and cyclin-dependent kinase 1. Besides, apoptosis was enhanced in IPGly animals, given by an increment of Bax/Bcl-2 ratio, Bad and PUMA mitochondrial expression, a concomitant increase in cytochrome c release and caspase-3 activation. Furthermore, hepatic levels of glycerol phosphate and markers of oxidative stress were increased in IPGly rats. Oxidative stress intermediates act as intracellular messengers, inducing p53 activation and changes in JNK and Erk signaling pathways, with JNK activation and Erk inhibition.

Conclusion
The present work provides novel data concerning the preventive actions of glycerol during the development of liver cancer and represents an economically feasible intervention to treat high-risk individuals.

Irisine: le lien entre la muscu et le renforcement osseux?

14/03/2018 | Etudes sur les hormones et Etudes Perte de poids et Etudes Anti-âge

 

Myokine—Irisin—and Its Effects Linking Bone and Muscle Function
Graziana Colaianni           Clinical Reviews in Bone and Mineral Metabolism March 2018, Volume 16, Issue 1, pp 16–21

Irisin is a myokine secreted by the skeletal muscle during physical activity both in mice and humans. Its first identified role was to activate the browning response in white adipocytes, subsequently triggering non-shivering thermogenesis; therefore, Irisin has raised great expectations as a potential target in the treatment of obesity. In 2015, we demonstrated that Irisin plays a central role in the control of bone mass, driving positive effects on cortical mineral density and bone mechanical properties. This effect on the bone was triggered using an Irisin dosage 70 times lower than the one needed to induce the browning response, suggesting that the skeleton is the primary target organ of this myokine. Moreover, our studies also highlighted the autocrine effect of Irisin on the skeletal muscle, overall suggesting that Irisin plays a fundamental role in the physiology of the musculoskeletal system. More recently, we demonstrated the efficacy of Irisin in preventing and restoring bone and muscle losses in a mouse model affected by disuse-induced osteoporosis and muscular atrophy. Hopefully, if future investigations will be confirmed in humans, it may lead to develop an Irisin-based therapy for physically disable or bedridden patients and it might also represent a countermeasure for astronauts subjected to microgravity.

L’acide carnosique du romarin comme protecteur articulaire?

13/03/2018 | Echauffement et blessures et Etudes Compléments alimentaires et Etudes Anti-âge

 

Carnosic acid inhibits inflammation response and joint destruction on osteoclasts, fibroblast-like synoviocytes, and collagen-induced arthritis rats
Mei Liu       J. Cell. Physiol.      9 March 2018

The discovery of new therapeutic drugs with the ability of preventing inflammation and joint destruction with less adverse effects is urgently needed for rheumatoid arthritis (RA). Carnosic acid (CA), a major phenolic compound isolated from the leaves of Rosemary (Rosmarinus officinalis L.), has been reported to have antioxidative and antimicrobial properties. However, its effects on RA have not been elucidated. Here, we investigated the effects of CA on osteoclasts and fibroblast-like synoviocytes in vitro and on collagen-induced arthritis (CIA) in Wistar rats in vivo. Our in vitro and in vivo studies showed that CA suppressed the expression of pro-inflammatory cytokines including TNFɑ, IL-1β, IL-6, IL-8, IL-17 and MMP-3, and downregulated the production of RANKL. More importantly, we observed that CA inhibited osteoclastogenesis and bone resorption in vitro and exerted therapeutic protection against joint destruction in vivo. Further biochemical analysis demonstrated that CA suppressed RANKL-induced activations of NF-κB and MAPKs (JNK and p38) leading to the downregulation of NFATc1.

Taken together, our findings provide the convincing evidence that rosemary derived CA is a promising natural compound for the treatment of RA.

Effet d’une supplémentation en corps cétoniques sur la glycémie?

17/02/2018 | Etudes Compléments alimentaires et Etudes Perte de poids et Etudes Anti-âge

 

Prior ingestion of exogenous ketone monoester attenuates the glycemic response to an oral glucose tolerance test in healthy young individuals
Etienne Myette-Côté              The Journal of Physiology               15 February 2018  

The main objectives of this study were threefold: (1) To determine whether acute ingestion of Kme; (R)-3-hydroxybutyl (R)-3-hydroxybutyrate impacts plasma glucose levels during a standardized oral glucose tolerance test (OGTT). (2) To compare changes in insulin concentrations and estimates of insulin sensitivity after acute Kme supplementation. Twenty healthy participants (n = 10 males/females) aged between 18–35 years took part in a randomized crossover study. After an overnight fast, participants consumed a Kme supplement (ΔG®; 0.45 ml kg−1 body weight) or placebo (water) 30 min before completing a 75-gram OGTT. Blood samples were collected every 15–30 min over a period of 2.5 h. Participants and study personnel performing laboratory analyses were blinded to condition. Kme acutely raised blood D-beta-hydroxybutyrate (β-OHB) to 3.2±0.6 mm within 30 min with levels remaining elevated throughout the entire OGTT. Compared to placebo, Kme significantly decreased glucose area under the curve (AUC; −16%, P = 0.001), non-esterified fatty acid (NEFA) AUC (-44%, P

< 0.001) and C-peptide incremental AUC (P = 0.005), while improving oral glucose insulin sensitivity index by ∼11% (P = 0.001).

In conclusion, a

Kme supplement that acutely increased β-OHB levels up to ∼3 mm attenuated the glycemic response to an OGTT in healthy humans. The reduction in glycemic response did not appear to be driven by an increase in insulin secretion, but was accompanied by improved markers of insulin sensitivity. These results suggest that ketone monoester supplements could have therapeutic potential in the management and prevention of metabolic disease.

Deca dick?

14/02/2018 | Etudes sur les hormones et Etudes Anti-âge

 

Nandrolone combined with strenuous resistance training reduces vascular nitric oxide bioavailability and impairs endothelium-dependent vasodilation
Steroids Volume 131, March 2018, Pages 7-13     ViniciusGuzzoni

Highlights
• Nandrolone plus strenuous RT impairs acetylcholine-mediated aorta vasodilation.
• Nandrolone plus strenuous RT increased reactive species of oxygen levels.
• Nandrolone plus strenuous RT dramatically reduced vascular NO bioavailability.
• Nandrolone plus strenuous RT increased arterial wall thickness.
• Combination of nandrolone and strenuous RT might lead endothelial dysfunction.

Anabolic Androgenic Steroids (AASs) misuse has increased among adolescents and recreational athletes due to their potential effects on muscle hypertrophy. On the other hand, AAS might induce alterations on cardiovascular system, although some controversies regarding AAS on vascular properties remain unknown. To address this question, we aimed to investigate the effects of high doses of nandrolone combined with strenuous resistance training (RT) on function and structure of thoracic aorta. Rats were randomized into four groups: non-trained vehicle (NTV), trained vehicle (TV), non-trained nandrolone (NTN), and trained nandrolone (TN), and submitted to 6 weeks of treatment with nandrolone (5 mg/kg, twice a week) and/or resistance training. In vitro response of thoracic aorta to acetylcholine (ACh) was analyzed. Vascular nitric oxide (NO) and reactive oxygen species (ROS) synthesis were evaluated using 4,5-diaminofluorescein diacetate (DAF-2) and hydroethidine fluorescent techniques, respectively. Thoracic aorta was processed for microscopy analyses and tunica media thickness was measured. ACh-mediated relaxation response was impaired in endothelium intact aortic rings isolated from trained rats (TV and TN) as compared with their matched non-trained groups. TN rats showed reduced ACh-mediated vasodilatation than NTN rats. NO production and bioavailability decreased in thoracic aorta of nandrolone-treated rats in relation to their matched non-trained group (NTN vs. NTV; TN vs. TV). ROS production and tunica media thickness were increased in TN rats when compared with TV rats.

These findings indicate that high doses of nandrolone combined with strenuous RT affect NO bioavailability and might induce endothelial dysfunction and arterial morphological alterations.

Les oméga 6 sont-ils pro- ou anti-inflammatoires?

14/12/2017 | Etudes Anti-âge

 

The associations of serum n-6 polyunsaturated fatty acids with serum C-reactive protein in men: the Kuopio Ischaemic Heart Disease Risk Factor Study
Jyrki K. Virtanen               European Journal of Clinical Nutrition (2017)


There are concerns that high intake of n-6 polyunsaturated fatty acids (PUFA) may promote inflammation, because the end-product of n-6 PUFA metabolism, arachidonic acid, is a precursor for pro-inflammatory eicosanoids. Our aim was to investigate cross-sectional associations of the serum n-6 PUFAs, objective biomarkers for exposure, with serum high-sensitivity C-reactive protein (CRP), a key inflammation marker.

Subjects/methods
The study included 1287 generally healthy men aged 42–60 years from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study, examined in 1984–1989. ANCOVA and logistic regression were used for analyses.

Results
In the multivariable-adjusted analyses, both serum total n-6 PUFA and linoleic acid, the predominant n-6 PUFA, were associated with lower CRP. The mean CRP concentrations in quartiles of linoleic acid were 1.86, 1.51, 1.53, and 1.37 mg/L (P-trend = 0.001). The odds ratio for elevated CRP (>3 mg/L) in the highest vs. the lowest quartile was 0.47 (95% confidence interval (CI) 0.25–0.87, P-trend = 0.01). Arachidonic acid or the mainly endogenously produced n-6 PUFAs, gamma-linolenic acid and dihomo-gamma-linolenic acid, were not associated with higher CRP, either. Age, body mass index, or serum long-chain n-3 PUFA concentration did not modify the associations (P-interactions > 0.14).

Conclusions
Serum n-6 PUFAs were not associated with increased inflammation in men. In contrast, the main n-6 PUFA linoleic acid had a strong inverse association with the key inflammation marker, CRP.

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