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Nathan Goodyear

Estrogenic regulation of skeletal muscle proteome: a study of premenopausal women and p... - 0 views

onlinelibrary.wiley.com/...full

estradiol menopause muscle hormones mitochondria aging female

shared by Nathan Goodyear on 10 Oct 17 - No Cached
  • Female aging is characterized by menopausal change in sex steroid hormones concomitant to increase in aging-related decrements in skeletal muscle performance that can be attenuated by HRT use
  • The major canonical pathways found to be differentially regulated included mitochondrial dysfunction, oxidative phosphorylation, glycolysis, and TCA-cycle, strong indicators for affected energy metabolism
  • E2 to exert anti-apoptotic effects in muscle progenitor cells by improving mitochondrial function
  • ...2 more annotations...
  • E2 is a major regulator of human skeletal muscle signaling in women
  • After menopause, when ovarian E2 production is ceased, the prevalence of cardio-metabolic diseases increases. Our result that different trajectories of the energy pathways in the skeletal muscle may be regulated by E2 provides candidate molecules as key targets for future interventions to prevent or treat postmenopausal metabolic dysregulation
  • Nathan Goodyear on 10 Oct 17
     
    Study finds Estradiol regulates human skeletal muscle cell signaling (mitochondrial function, oxidative phosphorylation, glycolysis, and TCA cycle) in study of pre/post menopause women through proteome analysis. This study would have been complete if they had carried to search beyond that of protein to epigenetics.
Nathan Goodyear

An integrative analysis reveals coordinated reprogramming of the epigenome and the tran... - 0 views

www.ncbi.nlm.nih.gov/...PMC4622000

exercise epigenetics muscle

shared by Nathan Goodyear on 03 Oct 17 - No Cached
  • contribution to the training response of the epigenome as a mediator between genes and environment
  • Differential DNA methylation was predominantly observed in enhancers, gene bodies and intergenic regions and less in CpG islands or promoters
  • highly consistent and associated modifications in methylation and expression, concordant with observed health-enhancing phenotypic adaptations, are induced by a physiological stimulus
  • ...34 more annotations...
  • The health benefits following exercise training are elicited by gene expression changes in skeletal muscle, which are fundamental to the remodeling process
  • there is increasing evidence that more short-term environmental factors can influence DNA methylation
  • dietary factors have the potency to alter the degree of DNA methylation in different tissues, 9,10 including skeletal muscle
  • In one study, a single bout of endurance-type exercise was shown to affect methylation at a few promoter CpG sites
  • In the context of diabetes, exercise training has been shown to affect genome-wide methylation pattern in skeletal muscle,13 as well as in adipose tissue.
  • physiological stressors can indeed affect DNA methylation
  • training intervention reshapes the epigenome and induces significant changes in DNA methylation
  • the findings from this tightly controlled human study strongly suggest that the regulation and maintenance of exercise training adaptation is to a large degree associated to epigenetic changes, especially in regulatory enhancer regions
  • Endurance training [after training (T2) vs. before training (T1)] induced significant (false discovery rate, FDR< 0.05) methylation changes at 4919 sites across the genome in the trained leg
  • identified 4076 differentially expressed genes
  • a complementary approach revealed that over 600 CpG sites correlated to the increase in citrate synthase activity, an objective measure of training response (Figure S4 and Dataset S14). This might imply that some of these sites could influence the degree of training response.
  • As expected by a physiological environmental trigger on adult tissue, the observed effect size on DNA methylation was small in comparison to disease states such as cancer
  • a preferential localization outside of CpG Islands/Shelves/Shores
  • endurance training especially influences enhancers
  • negative correlation was more prominent for probes in promoter/5′UTR/1st exon regions, while gene bodies had a stronger peak of positive correlation
  • The significant changes in DNA methylation, that primarily occurred in enhancer regions, were to a large extent associated with relevant changes in gene expression
  • The main findings of this study were that 3 months of endurance training in healthy human volunteers induced significant methylation changes at almost 5000 sites across the genome and significant differential expression of approximately 4000 genes
  • DMPs that increased in methylation were mainly associated to structural remodeling of the muscle and glucose metabolism, while the DMPs with decreased methylation were associated to inflammatory/immunological processes and transcriptional regulation
  • This suggests that the changes in methylation seen with training were not a random effect across the genome but rather a controlled process that likely contributes to skeletal muscle adaptation to endurance training
  • Correlation of the changes in DNA methylation to the changes in gene expression showed that the majority of significant methylation/expression pairs were found in the groups representing either increases in expression with a concomitant decrease in methylation or vice versa
  • The fraction of genes showing both significant decrease in methylation and upregulation was 7.5% of the DEGs or 2.3% of all genes detected in muscle tissue with at least one measured DNA methylation position. Correspondingly, 7.0% of the DEGs or 2.1% of all genes showed both significant increase in methylation and downregulation
  • we show that DNA methylation changes are associated to gene expression changes in roughly 20% of unique genes that significantly changed with training
  • Examples of structural genes include COL4A1, COL4A2 and LAMA4. These genes have also been identified as important for differences in responsiveness to endurance training
  • methylation status could be part of the mechanism behind variable training response
  • Among the metabolic genes, MDH1 catalyzes the reversible oxidation of malate to oxaloacetate, utilizing the NAD/NADH cofactor system in the citric acid cycle and NDUFA8 plays an important role in transferring electrons from NADH to the respiratory chain
  • PPP1R12A,
  • In the present study, methylation predominantly changed in enhancer regions with enrichment for binding motifs for different transcription factors suggesting that enhancer methylation may be highly relevant also in exercise biology
  • Of special interest in the biology of endurance training may be that MRFs, through binding to the PGC-1α core promoter, can regulate this well-studied co-factor for mitochondrial biogenesis
  • That endurance training led to an increased methylation in enhancer regions containing motifs for the MRFs and MEFs is somewhat counterintuitive since it should lead to the repression of the action of the above discussed transcription factors
  • decrease with training in this study, including CDCH15, MYH3, TNNT2, RYR1 and SH3GLB1
  • expression of MEF2A itself decreased with training
  • this study demonstrates that the transcriptional alterations in skeletal muscle in response to a long-term endurance exercise intervention are coupled to DNA methylation changes
  • We suggest that the training-induced coordinated epigenetic reprogramming mainly targets enhancer regions, thus contributing to differences in individual response to lifestyle interventions
  • a physiological health-enhancing stimulus can induce highly consistent modifications in DNA methylation that are associated to gene expression changes concordant with observed phenotypic adaptations
  • Nathan Goodyear on 03 Oct 17
     
    Exercise alters gene expression via methylation--the power of epigenetics.  Interestingly, the majority of the methylation was outside the CPG island regions.  This 3 month study found methylation of 5,000 sites across the genome resulting in altered expression of apps 4,000 genes.  The altered muscle changes of the endurance training was linked to DNA methylation changes.
Nathan Goodyear

JISSN | Full text | International Society of Sports Nutrition position stand: creatine ... - 0 views

www.jissn.com/6

creatine sports nutrition exercise

shared by Nathan Goodyear on 27 Jan 14 - No Cached
  • the energy supplied to rephosphorylate adenosine diphosphate (ADP) to adenosine triphosphate (ATP) during and following intense exercise is largely dependent on the amount of phosphocreatine (PCr) stored in the muscle
  • Creatine is chemically known as a non-protein nitrogen
  • It is synthesized in the liver and pancreas from the amino acids arginine, glycine, and methionine
  • ...26 more annotations...
  • Approximately 95% of the body's creatine is stored in skeletal muscle
  • About two thirds of the creatine found in skeletal muscle is stored as phosphocreatine (PCr) while the remaining amount of creatine is stored as free creatine
  • The body breaks down about 1 – 2% of the creatine pool per day (about 1–2 grams/day) into creatinine in the skeletal muscle
  • The magnitude of the increase in skeletal muscle creatine content is important because studies have reported performance changes to be correlated to this increase
  • "loading" protocol. This protocol is characterized by ingesting approximately 0.3 grams/kg/day of CM for 5 – 7 days (e.g., ≃5 grams taken four times per day) and 3–5 grams/day thereafter [18,22]. Research has shown a 10–40% increase in muscle creatine and PCr stores using this protocol
  • Additional research has reported that the loading protocol may only need to be 2–3 days in length to be beneficial, particularly if the ingestion coincides with protein and/or carbohydrate
  • A few studies have reported protocols with no loading period to be sufficient for increasing muscle creatine (3 g/d for 28 days)
  • Cycling protocols involve the consumption of "loading" doses for 3–5 days every 3 to 4 weeks
  • Most of these forms of creatine have been reported to be no better than traditional CM in terms of increasing strength or performance
  • Recent studies do suggest, however, that adding β-alanine to CM may produce greater effects than CM alone
  • These investigations indicate that the combination may have greater effects on strength, lean mass, and body fat percentage; in addition to delaying neuromuscular fatigue
  • creatine phosphate has been reported to be as effective as CM at improving LBM and strength
  • Green et al. [24] reported that adding 93 g of carbohydrate to 5 g of CM increased total muscle creatine by 60%
  • Steenge et al. [23] reported that adding 47 g of carbohydrate and 50 g of protein to CM was as effective at promoting muscle retention of creatine as adding 96 g of carbohydrate.
  • It appears that combining CM with carbohydrate or carbohydrate and protein produces optimal results
  • Studies suggest that increasing skeletal muscle creatine uptake may enhance the benefits of training
  • Nearly 70% of these studies have reported a significant improvement in exercise capacity,
  • Long-term CM supplementation appears to enhance the overall quality of training, leading to 5 to 15% greater gains in strength and performance
  • Nearly all studies indicate that "proper" CM supplementation increases body mass by about 1 to 2 kg in the first week of loading
  • short-term adaptations reported from CM supplementation include increased cycling power, total work performed on the bench press and jump squat, as well as improved sport performance in sprinting, swimming, and soccer
  • Long-term adaptations when combining CM supplementation with training include increased muscle creatine and PCr content, lean body mass, strength, sprint performance, power, rate of force development, and muscle diameter
  • subjects taking CM typically gain about twice as much body mass and/or fat free mass (i.e., an extra 2 to 4 pounds of muscle mass during 4 to 12 weeks of training) than subjects taking a placebo
  • The gains in muscle mass appear to be a result of an improved ability to perform high-intensity exercise via increased PCr availability and enhanced ATP synthesis, thereby enabling an athlete to train harder
  • there is no evidence to support the notion that normal creatine intakes (< 25 g/d) in healthy adults cause renal dysfunction
  • no long-term side effects have been observed in athletes (up to 5 years),
  • One cohort of patients taking 1.5 – 3 grams/day of CM has been monitored since 1981 with no significant side effects
  • Nathan Goodyear on 27 Jan 14
     
    Nice review of the data, up to the publication date, on creatine.
Nathan Goodyear

Improving the Vitamin D Status of Vitamin D Deficient Adults Is Associated With Improve... - 0 views

jcem.endojournals.org/...E509.abstract

vitamin vitamins vitamin D mitochondria skeletal muscle

shared by Nathan Goodyear on 18 Mar 13 - No Cached
  • Nathan Goodyear on 18 Mar 13
     
    Fascinating link between vitamin D and mitochondria function in skeletal muscle.  Vitamin D replacement was found to improve mitochondrial function, improve post exercise discomfort in those with vitamin D deficiency.  Obviously, this provides support for a link between vitamin D and mitochondrial function.  This could provide an important tool in the recovery phase in athletes.
Nathan Goodyear

Skeletal muscle insulin resistance is fundamental ... [J Cardiometab Syndr. 2006] - Pub... - 0 views

www.ncbi.nlm.nih.gov/...17675899

insulin resistance metabolic syndrome skeletal muscle

shared by Nathan Goodyear on 11 Jul 11 - No Cached
  • Nathan Goodyear on 11 Jul 11
     
    skeletal muscles are key to metabolic syndrome
Nathan Goodyear

Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle: Cell Metabolism - 0 views

www.cell.com/...S1550-4131(12)00005-8

exercise methylation epigenetics muscle

shared by Nathan Goodyear on 03 Oct 17 - No Cached
  • our results provide evidence to suggest that acute exercise induces gene-specific DNA hypomethylation in human skeletal muscle
  • Our results suggest that DNA methylation is a component of the exercise-induced effect on expression of these genes.
  • Caffeine exposure decreased promoter methylation of Pgc-1α, Tfam, Mef2a, Cs, and Pdk4
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  • the effect of exercise on DNA methylation in human skeletal muscle and provide evidence that acute exercise alters promoter methylation of exercise-responsive genes in a dose-dependent manner
  • DNA methylation was unaltered 48 hr after a 3-week exercise training program, whereas RNA expression of PGC-1α and TFAM promoters was elevated (data not shown), further suggesting that DNA hypomethylation is a transient mechanism involved in mRNA synthesis
  • Our findings that ionomycin, AICAR, or ROS production increased mRNA expression without altering promoter methylation may support the notion that DNA methylation does not exclusively control exercise-induced gene expression
  • acute exercise leads to transient changes in DNA methylation in adult skeletal muscle
  • Nathan Goodyear on 03 Oct 17
     
    Small study finds acute exercise is associated with epigenetic alteration of muscle through methylation.  This study found a hypomethylation of the genes PGC-1alpha, PDK4, and PPAR-delta with a respondent increase in expression.  The methylation activity was in the promoter region of these genes.
Nathan Goodyear

Muscles, exercise and obesity: skeletal muscle as a secretory organ : Abstract : Nature... - 0 views

www.nature.com/...nrendo.2012.49.html

obesity physical activity exercise muscle muscles cytokines myokines

shared by Nathan Goodyear on 16 Sep 14 - No Cached
  • Nathan Goodyear on 16 Sep 14
     
    Skeletal muscles are much more than just about contraction.  There produce inflammatory cytokines and other signals that have endocrine-like effects.  This article calls them myokines.  A decrease in physical activity would leave an altered myokine response effecting the liver, adipose tissue, immune system and pancreatic function.
Nathan Goodyear

Branched Chain Amino Acid Supplementation for Patients with Cirrhosis | Clinical Correl... - 0 views

www.clinicalcorrelations.org/?p=3544

BCCA branched chain amino acids liver cirrhosis hepatitis amino acids

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • low level of BCAAs in patients with cirrhosis is hypothesized to be one of multiple factors responsible for development of hepatic encephalopathy
  • supplementation of BCAAs is thought to facilitate ammonia detoxification by supporting synthesis of glutamine, one of the non-branched chain amino acids, in skeletal muscle and in the brain as well as diminishing the influx of AAAs across the blood-brain barrier
  • oral BCAA supplementation is more useful in chronic encephalopathic patients than is parenteral BCAA supplementation in patients with acute encephalopathy
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  • malnutrition progressing to cachexia is another common manifestation of cirrhosis
  • Malnutrition can be mitigated with BCAA supplementation
  • Studies show that administration of amino acid formulas enriched with BCAAs can reduce protein loss, support protein synthesis, and improve nutritional status of patients with chronic liver disease
  • Leucine has been shown to be the most effective of the BCAAs because it acts via multiple pathways to stimulate protein synthesis
  • BCAAs metabolites inhibit proteolysis
  • Patients with cirrhosis have both insulin deficiency and insulin resistance
  • BCAAs (particularly leucine) help to reverse the catabolic, hyperglucagonemic state of cirrhosis both by stimulating insulin release from the pancreatic β cells and by decreasing insulin resistance allowing for better glucose utilization
  • Coadministration of BCAAs and glucose has been found to be particularly useful
  • BCAA supplementation improves protein-energy malnutrition by improving utilization of glucose, thereby diminishing the drive for proteolysis, inhibiting protein breakdown, and stimulating protein synthesis
  • Cirrhotic patients have impaired immune defense, characterized by defective phagocytic activity and impaired intracellular killing activity
  • another effect of BCAA supplementation is improvement of phagocytic function of neutrophils and possibly improvement in natural killer T (NKT) cell lymphocyte activity
  • BCAA supplementation may reduce the risk of infection in patients with advanced cirrhosis not only through improvement in protein-energy malnutrition but also by directly improving the function of the immune cells themselves
  • BCAA administration has also been shown to have a positive effect on liver regeneration
  • A proposed mechanism for improved liver regeneration is the stimulatory effect of BCAAs (particularly leucine) on the secretion of hepatocyte growth factor by hepatic stellate cells
  • BCAAs activate rapamycin signaling pathways which promotes albumin synthesis in the liver as well as protein and glycogen synthesis in muscle tissue
  • Chemical improvement with BCAA treatment is demonstrated by recovery of serum albumin and lowering of serum bilirubin levels
  • long-term oral BCAA supplementation was useful in staving off malnutrition and improving survival by preventing end-stage fatal complications of cirrhosis such as hepatic failure and gastrointestinal bleeding
  • The incidence of death by any cause, development of liver cancer, rupture of esophageal varices, or progression to hepatic failure was decreased in the group that received BCAA supplementation
  • Patients receiving BCAA supplementation also have a lower average hospital admission rate, better nutritional status, and better liver function tests
  • patients taking BCAA supplementation report improved quality of life
  • BCAAs have been shown to mitigate hepatic encephalopathy, cachexia, and infection rates, complications associated with the progression of hepatic cirrhosis
  • BCAAs make up 20-25% of the protein content of most foods
  • Highest levels are found in casein whey protein of dairy products and vegetables, such as corn and mushrooms. Other sources include egg albumin, beans, peanuts and brown rice bran
  • In addition to BCAAs from diet, oral supplements of BCAAs can be used
  • Oral supplementation tends to provide a better hepatic supply of BCAAs for patients able to tolerate PO nutrition as compared with IV supplementation, especially when treating symptoms of hepatic encephalopathy
  • Coadministration of BCAAs with carnitine and zinc has also been shown to increase ammonia metabolism further reducing the encephalopathic symptoms
  • Cirrhotic patients benefit from eating frequent, small meals that prevent long fasts which place the patient in a catabolic state
  • the best time for BCAA supplementation is at bedtime to improve the catabolic state during starvation in early morning fasting
  • A late night nutritional snack reduces symptoms of weakness and fatigability, lowers postprandial hyperglycemia, increases skeletal muscle mass,[25] improves nitrogen balance, and increases serum albumin levels.[26] Nocturnal BCAAs even improve serum albumin in cirrhotic patients who show no improvement with daytime BCAAs
  • Protein-energy malnutrition (PEM), with low serum albumin and low muscle mass, occurs in 65-90% of cases of advanced cirrhosis
  • hyperglucagonemia results in a catabolic state eventually producing anorexia and cachexia
  • BCAAs are further depleted from the circulation due to increased uptake by skeletal muscles that use the BCAAs in the synthesis of glutamine, which is produced in order to clear the ammonia that is not cleared by the failing liver
  • patients with chronic liver disease, particularly cirrhosis, routinely have decreased BCAAs and increased aromatic amino acids (AAAs) in their circulation
  • Maintaining a higher serum albumin in patients with cirrhosis is associated with decreased mortality and improved quality of life
  • the serum BCAA concentration is strongly correlated with the serum albumin level
  • Nathan Goodyear on 05 Oct 15
     
    great review of cirrhosis and BCCA supplementation.
Nathan Goodyear

Molecular Cell - A Muscle-Specific Insulin Receptor Knockout Exhibits Features of the M... - 0 views

www.cell.com/...S1097-2765(00)80155-0

metabolic syndrome glucose insulin fat metabolism skeletal muscle resistance

shared by Nathan Goodyear on 11 Jul 11 - No Cached
  • Nathan Goodyear on 11 Jul 11
     
    skeletal muscles very important in fat metabolism
Nathan Goodyear

Impact of an Exercise Intervention on DNA Methylation in Skeletal Muscle From First-Deg... - 0 views

www.ncbi.nlm.nih.gov/...PMC3501844

exercise diabetes epigenetics muscle mitochondria VO2max

shared by Nathan Goodyear on 03 Oct 17 - No Cached
  • epigenetic modifications of single genes have been shown to affect the pathogenesis of T2D
  • An FH of T2D is an independent predictor of future risk for the disease
  • exercise for 6 months is associated with epigenetic changes, e.g., decreased DNA methylation of RUNX1 and MEF2A, two key transcription factors involved in exercise training (42–44), of THADA, previously associated with T2D (1), and of NDUFC2, which is part of the respiratory chain (45) was observed after exercise
  • ...4 more annotations...
  • exercise changed both DNA methylation and expression of a number of genes, including ADIPOR1, ADIPOR2, and BDKRB2, encoding receptors for adiponectin and bradykinin, respectively, which both regulate metabolism in muscle
  • we cannot draw a conclusion as to whether differential expression is a consequence rather than a cause of changes in methylation
  • ageing is associated with increased DNA methylation and decreased expression of genes involved in oxidative phosphorylation in human muscle
  • exercise can induce genome-wide epigenetic changes in human muscle and that the response may differ in people with different genetic predispositions to metabolic disease
  • Nathan Goodyear on 03 Oct 17
     
    Six months of exercise induce epigenetic changes through decrease in methylation.  This study was designed to look at those with a family risk of DM.  They found a difference in the methylation status of muscle between those with a family h/o diabetes and those without.  This would have implications in therapeutic difference prior to diagnosis.  Even a increased VO2max and skeletal muscle mitochondrial density was found to be the result of decreased methylation of the NDUFC2 gene after exercise.
Nathan Goodyear

Testosterone: a metabolic hormone in health and disease - 0 views

joe.endocrinology-journals.org/...R25.full

male hormone hormones testosterone hypogonadal-obesity-adipocytokine hypothesis

shared by Nathan Goodyear on 08 May 13 - No Cached
  • E2 and the inflammatory adipocytokines tumour necrosis factor α (TNFα) and interleukin 6 (IL6) inhibit hypothalamic production of GNRH and subsequent release of LH and FSH from the pituitary
  • Leptin, an adipose-derived hormone with a well-known role in regulation of body weight and food intake, also induces LH release under normal conditions via stimulation of hypothalamic GNRH neurons
  • In human obesity, whereby adipocytes are producing elevated amounts of leptin, the hypothalamic–pituitary axis becomes leptin resistant
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  • there is evidence from animal studies that leptin resistance, inflammation and oestrogens inhibit neuronal release of kisspeptin
  • Beyond hypothalamic action, leptin also directly inhibits the stimulatory action of gonadotrophins on the Leydig cells of the testis to decrease testosterone production; therefore, elevated leptin levels in obesity may further diminish androgen status
  • increasing insulin resistance assessed by glucose tolerence test and hypoglycemic clamp was shown to be associated with a decrease in Leydig cell testosterone secretion in men
  • ADT for the treatment of prostatic carcinoma in some large epidemiological studies has been shown to be associated with an increased risk of developing MetS and T2DM
  • Non-diabetic men undergoing androgen ablation show increased occurrence of new-onset diabetes and demonstrate elevated insulin levels and worsening glycaemic control
  • Prostate cancer patients with pre-existing T2DM show a further deterioration of insulin resistance and worsening of diabetic control following ADT
  • The response to testosterone replacement of insulin sensitivity is in part dependent on the androgen receptor (AR)
  • Low levels of testosterone have been associated with an atherogenic lipoprotein profile, characterised by high LDL and triglyceride levels
  • a positive correlation between serum testosterone and HDL has been reported in both healthy and diabetic men
  • up to 70% of the body's insulin sensitivity is accounted for by muscle
  • Testosterone deficiency is associated with a decrease in lean body mass
  • relative muscle mass is inversely associated with insulin resistance and pre-diabetes
  • GLUT4 and IRS1 were up-regulated in cultured adipocytes and skeletal muscle cells following testosterone treatment at low dose and short-time incubations
  • local conversion of testosterone to DHT and activation of AR may be important for glucose uptake
  • inverse correlation between testosterone levels and adverse mitochondrial function
  • orchidectomy of male Wistar rats and associated testosterone deficiency induced increased absorption of glucose from the intestine
  • (Kelley & Mandarino 2000). Frederiksen et al. (2012a) recently demonstrated that testosterone may influence components of metabolic flexibility as 6 months of transdermal testosterone treatment in aging men with low–normal bioavailable testosterone levels increased lipid oxidation and decreased glucose oxidation during the fasting state.
  • Decreased lipid oxidation coupled with diet-induced chronic FA elevation is linked to increased accumulation of myocellular lipid, in particular diacylglycerol and/or ceramide in myocytes
  • In the Chang human adult liver cell line, insulin receptor mRNA expression was significantly increased following exposure to testosterone
  • Testosterone deprivation via castration of male rats led to decreased expression of Glut4 in liver tissue, as well as adipose and muscle
  • oestrogen was found to increase the expression of insulin receptors in insulin-resistant HepG2 human liver cell line
  • FFA decrease hepatic insulin binding and extraction, increase hepatic gluconeogenesis and increase hepatic insulin resistance.
  • Only one, albeit large-scale, population-based cross-sectional study reports an association between low serum testosterone concentrations and hepatic steatosis in men (Völzke et al. 2010)
  • This suggests that testosterone may confer some of its beneficial effects on hepatic lipid metabolism via conversion to E2 and subsequent activation of ERα.
  • hypogonadal men exhibiting a reduced lean body mass and an increased fat mass, abdominal or central obesity
  • visceral adipose tissue was inversely correlated with bioavailable testosterone
  • there was no change in visceral fat mass in aged men with low testosterone levels following 6 months of transdermal TRT, yet subcutaneous fat mass was significantly reduced in both the thigh and the abdominal areas when analysed by MRI (Frederiksen et al. 2012b)
  • ADT of prostate cancer patients increased both visceral and subcutaneous abdominal fat in a 12-month prospective observational study (Hamilton et al. 2011)
  • Catecholamines are the major lipolysis regulating hormones in man and regulate adipocyte lipolysis through activation of adenylate cyclase to produce cAMP
  • deficiency of androgen action decreases lipolysis and is primarily responsible for the induction of obesity (Yanase et al. 2008)
  • may be some regional differences in the action of testosterone on subcutaneous and visceral adipose function
  • proinflammatory adipocytokines IL1, IL6 and TNFα are increased in obesity with a downstream effect that stimulates liver production of CRP
  • observational evidence suggests that IL1β, IL6, TNFα and CRP are inversely associated with serum testosterone levels in patients
  • TRT has been reported to significantly reduce these proinflammatory mediators
  • This suggests a role for AR in the metabolic actions of testosterone on fat accumulation and adipose tissue inflammatory response
  • testosterone treatment may have beneficial effects on preventing the pathogenesis of obesity by inhibiting adipogenesis, decreasing triglyceride uptake and storage, increasing lipolysis, influencing lipoprotein content and function and may directly reduce fat mass and increase muscle mass
  • Early interventional studies suggest that TRT in hypogonadal men with T2DM and/or MetS has beneficial effects on lipids, adiposity and parameters of insulin sensitivity and glucose control
  • Evidence that whole-body insulin sensitivity is reduced in testosterone deficiency and increases with testosterone replacement supports a key role of this hormone in glucose and lipid metabolism
  • Impaired insulin sensitivity in these three tissues is characterised by defects in insulin-stimulated glucose transport activity, in particular into skeletal muscle, impaired insulin-mediated inhibition of hepatic glucose production and stimulation of glycogen synthesis in liver, and a reduced ability of insulin to inhibit lipolysis in adipose tissue
  • Nathan Goodyear on 08 May 13
     
    Great review of the Hypogonadal-obesity-adipocytokine hypothesis.
Nathan Goodyear

Inflammation and insulin resistance 10.1016/j.febslet.2007.11.057 : FEBS Letters | Scie... - 0 views

www.sciencedirect.com/...S0014579307012082

inflammation insulin resistance IR PPAR TNF-alpha IL-6 IL-10 IL-1Beta JNK GLT-4 Resistin adiponectin Gherlin NF-kapppB iNOS lkkb obesity TLR-4

shared by Nathan Goodyear on 10 Jan 12 - No Cached
  • A subsequent study by Yuan et al. showed that Tnf treatment of 3T3L1 adipocytes induces insulin resistance and that this could be prevented by pretreatment of cells with aspirin
  • Activation of the Tnf receptor results in stimulation of NFκB signaling via Ikkb
  • Insulin is a pleiotropic hormone
  • ...25 more annotations...
  • the percentage of macrophages in a given adipose tissue depot is positively correlated with adiposity and adipocyte size
  • Il-10 is an anti-inflammatory cytokine produced by macrophages and lymphocytes
  • Il-10 exerts its anti-inflammatory activity by inhibiting Tnf-induced NFκB activation by reducing IKK activity [38]
  • adipose tissue macrophages are responsible for nearly all adipose tissue Tnf expression and a significant portion of Nos2 and Il6 expression
  • One theory holds that the expansion of adipose tissue leads to adipocyte hypertrophy and hyperplasia and that large adipocytes outstrip the local oxygen supply leading to cell autonomous hypoxia with activation of cellular stress pathways
  • The use of the anti-inflammatory compounds, salicylate and its derivative aspirin, for treating symptoms of T2DM dates back over 100 years
  • elevated levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin (IL-8) have all been reported in various diabetic and insulin resistant states
  • overnutrition and obesity are often accompanied by elevations in tissue and circulating FFA concentrations, and saturated FFAs can directly activate pro-inflammatory responses
  • Adipokines such as resistin, leptin and adiponectin, which are secreted by adipocytes, can also affect inflammation and insulin sensitivity
  • In skeletal muscle insulin promotes glucose uptake by stimulating translocation of the GLUT4 glucose transporter
  • macrophages are also capable of undergoing a phenotypic switch from an M1 state, which was defined as the “classically activated” pro-inflammatory macrophage, to the M2 state or the “alternatively activated” non-inflammatory cell
  • saturated fatty acids are the most potent inducers of this inflammatory response
  • Several inducers of insulin resistance, including FFAs, pro-inflammatory cytokines and oxidative stress, activate the expression of Nos2, the gene that encodes iNOS (reviewed in [33]
  • Adipose tissue insulin signaling results in decreased hormone sensitive lipase activity and this anti-lipolytic effect inhibits free fatty acid (FFA) efflux out of adipocytes.
  • In the liver, insulin inhibits the expression of key gluconeogenic enzymes and, therefore, insulin resistance in liver leads to elevated hepatic glucose production
  • elevated JNK activity in liver, adipose tissue and skeletal muscle of obese insulin resistant mice, and knockout of Jnk1 (Jnk1−/−) leads to amelioration of insulin resistance in high fat diet
  • Adipose tissue from obese mice contains proportionately more M1 macrophages, whereas, lean adipose tissue contains more M2 macrophages, and increased M1 content positively correlates with inflammation, macrophage infiltration and insulin resistance
  • C-reactive protein (CRP)
  • these studies highlight the possibility that increased iNOS activity plays a direct role in the pathogenesis of insulin resistance
  • the important role of Ikkb in the development of obesity and inflammation-induced insulin resistance.
  • It is probable that local concentrations of inflammatory mediators, such as FFAs, Tnf or other cytokines/adipokines contribute to this polarity switch
  • Tnf and other cytokines/chemokines are symptomatic of inflammation, and while they propagate and/or maintain the inflammatory state, they are not the initial cause(s) of inflammation
  • Tlr4, in particular, is stimulated by lipopolysaccharide (LPS), an endotoxin released by gram-negative bacteria
  • Tlr4 belongs to the family of Toll-like receptors that function as pattern recognition receptors that guard against microorganismal infections as part of the innate immune system.
  • Tlr4 stimulation results in the activation of both Ikkb/NFκB and JNK/AP-1 signaling, culminating in the expression and secretion of pro-inflammatory cytokines/chemokines, including, Il1b, IL-6, Tnf, Mcp1, etc. (reviewed in [57
  • Nathan Goodyear on 10 Jan 12
     
    Great review of all the known components in the inflammation, insulin resistance link
Nathan Goodyear

Scopus - Document details - 0 views

www.scopus.com/...display.url

high protein amino acid diet insulin resistance

shared by Nathan Goodyear on 21 Oct 13 - No Cached
  • Nathan Goodyear on 21 Oct 13
     
    Overnutrition through high protein intake associated with liver and skeletal muscle insulin resistance.
Nathan Goodyear

Overactivation of S6 Kinase 1 as a Cause of Human Insulin Resistance During Increased A... - 0 views

diabetes.diabetesjournals.org/...2674

high protein diet dietary insulin resistance

shared by Nathan Goodyear on 21 Oct 13 - No Cached
  • Nathan Goodyear on 21 Oct 13
     
    High protein intake can lead to insulin resistance.  Glucose regulation by insulin and skeletal muscle removal of glucose is disrupted by high amino acid intake through disruption of secondary insulin signaling.
Nathan Goodyear

Scopus - Document details - 0 views

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amino acids high protein diet insulin resistance

shared by Nathan Goodyear on 21 Oct 13 - No Cached
  • Nathan Goodyear on 21 Oct 13
     
    Amino acids contribute to skeletal muscle insulin resistance.  A marked glycogen synthesis decrease (64%) was found in this study.
Nathan Goodyear

Frontiers | Sarcopenia and Androgens: A Link between Pathology and Treatment | Endocrin... - 0 views

journal.frontiersin.org/...full

sarcopenia muscle loss

shared by Nathan Goodyear on 16 Apr 15 - No Cached
  • sarcopenia induces a change in the proportion of skeletal muscle fibers, inducing a shift from type II (fast) to type I (slow) fibers as well as preferential loss of type II fibers
  • testosterone stimulates protein synthesis by both a short-term mechanism-rapid activation of pre-existing components of the translational apparatus- and a long-term mechanism-increase in cell or tissue capacity at the protein synthesis level leading to increase in ribosome quantity
  • testosterone induces an increase in cross-sectional area (CSA) in type I and II muscle fibers and in myonuclear quantity, indicating that testosterone exerts more of a hypertrophic than a hyperplasic effect on skeletal muscle
  • Nathan Goodyear on 16 Apr 15
     
    good discussion of sarcopenia.
Nathan Goodyear

α-Lipoic acid increases energy expenditure by enhancing adenosine monophospha... - 0 views

www.metabolismjournal.com/...abstract

alpha lipoic acid ALA

shared by Nathan Goodyear on 07 May 11 - No Cached
  • LA improves skeletal muscle energy metabolism
  • LA increases lean mass loss
  • Nathan Goodyear on 07 May 11
     
    alpha lipoic acid improves energy production, lean mass and weight loss
Nathan Goodyear

Exercise Induces Hippocampal BDNF through a PGC-1α/FNDC5 Pathway: Cell Metabo... - 0 views

www.cell.com/...S1550-4131(13)00377-X

brain memory focus attention learning exercise BDNF brain derived neurotrophic factor PGC-1alpha irisin FNDC5 hippocampus cognition

shared by Nathan Goodyear on 12 Aug 14 - No Cached
  • Nathan Goodyear on 12 Aug 14
     
    Brain benefits of exercise explained.  Exercise increases hippocampal BDNF via PGC-1alpha from skeletal muscle.
wheelchairindia9

Tynor PUF Liner Skin Traction Set - 0 views

www.wheelchairindia.com/...or-PUF-Liner-Skin-Traction-Set

Tynor PUF Liner Skin Traction Set skin traction set PUF Liner Skin Traction Set skin traction set (puf liner) tynor skin traction set tynor skin traction skin traction set puf liner

shared by wheelchairindia9 on 22 Mar 16 - No Cached
  • wheelchairindia9 on 22 Mar 16
     
    Tynor PUF Liner Skin Traction Set Skin traction Set (PUF liner) is used for providing indirect traction to leg or the arm to reduce fractures, skeletal deformities, muscle contractures, muscle spasms, pressure on nerves or regain normal length and alignment of involved bone. Hypoallergenic. Extra porous. Controlled adhesion and friction. Extra comfortable. Tynor PUF Liner Skin Traction Set Features Available as Complete Kit Convenient for emergencies Cost effective High performance Inbuilt cord, Quick to apply Foam liner and Bandage High performance crepe bandage for extra security Enhanced skin friction of the foam liner Easy application and removal Measure distance from knee to foot. Cut Liners for accurate use
fnfdoc

How Lupus Affects The Health? - 0 views

www.fnfdoc.com/...lupus-affects-health

Lupus SLE

shared by fnfdoc on 29 Apr 18 - No Cached
  • fnfdoc on 29 Apr 18
     
    SLE or Lupus is an autoimmune disease that causes inflammation of the organs and swelling of the joints. It has vast effects on the renal, skeletal, gastrointestinal and blood systems. It affects mostly people of Chinese and African origin and presents in a capricious and unpredictable manner.
  • fnfdoc on 09 May 18
     
    10 May Is Lupus Day We Must Know About Lupus
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