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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
  • ...39 more annotations...
  • 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

Beyond the male sex hormone: deciphering the metabolic and vascular actions of testoste... - 0 views

joe.endocrinology-journals.org/...C1.full

AR androgen receptors androgen receptor testosterone androgen receptors Diabetes metabolic syndrome MetS CVD cardiovascular disease men hormone hormones male

shared by Nathan Goodyear on 08 May 13 - No Cached
  • androgen deprivation therapy results in unfavorable changes in body composition, insulin resistance, and dyslipidemia and predisposes men to develop atherosclerosis and an increased risk of cardiovascular mortality
  • The hypogonadal–obesity cycle hypothesis was originally proposed by Cohen in 1999 to explain the relationship between low testosterone levels and metabolic disease. It was based on the finding that obesity impairs testosterone levels by increasing the aromatization of testosterone to estradiol, while low testosterone levels promote increased fat deposition
  • adipocytokines contribute to low testosterone levels as well as to the processes underlying metabolic syndromes and type 2 diabetes
  • ...15 more annotations...
  • hypogonadal–obesity–adipocytokine hypothesis
  • The presence of estradiol and the adipocytokines TNF-α, IL6, and leptin (as a result of leptin resistance in obesity) inhibits the hypothalamic–pituitary–testicular axis response to decreasing androgen levels
  • An increasing number of studies have illustrated the potential for applying metabolomics to the field of androgen research
  • As early as the 1940s, the therapeutic use of testosterone was reported to improve angina pectoris in men with coronary artery disease
  • most of the epidemiological studies reported increased cardiovascular risk and mortality in men with low testosterone levels
  • long-term testosterone replacement appears to be a safe and effective means of treating hypogonadal elderly men
  • a recent interventional trial showed that testosterone treatment was associated with decreased mortality when compared with no testosterone treatment in an observational cohort of men with low testosterone levels
  • a number of short-term studies conducted support the notion that testosterone therapy reduces the cardiovascular risk
  • The majority of animal studies support the hypothesis that the actions of testosterone on vascular relaxation are both endothelium-dependent and -independent vasodilatory effects
  • Endothelial-dependent actions of testosterone increase the expression or activity of endothelial nitric oxide synthase and enhance nitric oxide production, which in turn activates cyclic guanosine monophosphate to induce vasorelaxation in smooth muscle cells
  • Endothelial-independent mechanisms of testosterone are believed to occur primarily via inhibition of voltage-operated Ca2+ channels and/or activation of K+ channels in smooth muscle cells
  • Testosterone may also inhibit intracellular Ca2+ influx via store-operated Ca2+ channels by blocking the response to prostaglandin F2α
  • testosterone has demonstrated anti-inflammatory effects to protect against atherogenesis in animal studies
  • both genomic AR activation to modulate gene transcription and non-genomic activation to modulate the rapid intracellular signaling pathways of ion channels may mediate testosterone effects on vascular function and inflammation.
  • Butenandt & Ruzicka first showed how testosterone is synthesized and responsible for masculine characteristics in the early 1930s
  • Nathan Goodyear on 08 May 13
     
    Awesome review on the current understanding of Testosterone and Diabetes, metabolic syndrome, and CVD.  This article even goes into the literature on androgen receptors.
Nathan Goodyear

Effect of Exogenous Thyroid Hormone Intake on the Interpretation of Serum TSH Test Results - 0 views

www.thyroidscience.com/...warmingham.7.18.10.pdf

TSH thyroid hypothyoidism Warmingham hypothesis hypothyroid

shared by Nathan Goodyear on 02 Feb 12 - No Cached
  • Nathan Goodyear on 02 Feb 12
     
    TSH is promoted as the test of choice to diagnosis and monitor thyroid dysfunction. However, Warmingham hypothesis, would suggest otherwise.
Nathan Goodyear

How environmental and genetic factors combine to c... [Neurotoxicology. 2008] - PubMed ... - 0 views

www.ncbi.nlm.nih.gov/...18031821

autism spectrum disorders ASD

shared by Nathan Goodyear on 05 Jul 11 - No Cached
  • Genetic polymorphisms adversely affecting sulfur metabolism, methylation, detoxification, dopamine signaling and the formation of neuronal networks occur more frequently in autistic subjects.
  • a "redox/methylation hypothesis of autism" is described, in which oxidative stress, initiated by environment factors in genetically vulnerable individuals, leads to impaired methylation and neurological deficits secondary to reductions in the capacity for synchronizing neural networks.
  • Nathan Goodyear on 05 Jul 11
     
    proposed hypothesis of autism
Nathan Goodyear

Ascorbate in pharmacologic concentrations selectively generates ascorbate radical and h... - 0 views

www.ncbi.nlm.nih.gov/...PMC1885574

vitamin C ascorbic acid Cancer

shared by Nathan Goodyear on 05 Mar 18 - No Cached
  • Proposed mechanism
  • The data show that pharmacologic ascorbate concentrations produced Asc•− selectively in extracellular fluid compared with blood and that H2O2 formation occurred when Asc•− concentrations were >100 nM in extracellular fluid.
  • These data validate the hypothesis that ascorbate is a prodrug for selective delivery of reactive species to the extravascular space
  • ...22 more annotations...
  • pharmacologic ascorbate as a prooxidant drug for therapeutic use.
  • Recently we reported that pharmacologic ascorbic acid concentrations produced H2O2 concentrations of ≥25 μM, causing cancer cell death in vitro
  • We found that H2O2 concentrations generated in vivo were those that caused cancer cell death in vitro
  • When ascorbate was given parenterally, Asc•−, the product of a loss of one electron from ascorbate, was detected preferentially in extracellular fluid compared with blood
  • Asc•− generation in extracellular fluid depended on the ascorbate dose and the resulting concentrations
  • With i.v. administration of ascorbate, Asc•− concentrations were as much as 12-fold greater in extracellular fluid compared to blood and approached 250 nM
  • In blood, such Asc•− concentrations were never produced and were always <50 nM
  • These data are all consistent with the hypothesis that pharmacologic ascorbate concentrations in vivo serve as a prodrug for selective delivery of H2O2 to the extracellular space
  • After oral ingestion, control of intracellular and extracellular ascorbate concentrations is mediated by three mechanisms: intestinal absorption, tissue transport, and renal reabsorption
  • intestinal absorption, or bioavailability, declines at doses >200 mg
    • Nathan Goodyear
      Nathan Goodyear on 05 Mar 18
       
      significant limitation of gut absorption of vitamin C--at 200 mg po.
  • corresponding to plasma concentrations of ≈60 μM
    • Nathan Goodyear
      Nathan Goodyear on 05 Mar 18
       
      equates to 0.06 mM.  Max blood levels found with po AA dosing has been 0.22 mM
  • at approximately this concentration, the ascorbate tissue transporter SVCT2 approaches Vmax, and tissues appear to be saturated
    • Nathan Goodyear
      Nathan Goodyear on 05 Mar 18
       
      SVCT2 Rc in gut reach max binding.
  • also at ≈60 μM, renal reabsorption approaches saturation, and excess ascorbate is excreted in urine
  • Parenteral administration bypasses tight control
  • When tight control is bypassed, H2O2 forms in the extracellular space
  • in vivo validation of ascorbate as a prodrug for selective H2O2 formation
  • Temporarily bypassing tight control with parenteral administration of ascorbate allows H2O2 to form in discrete time periods only, decreasing likelihood of harm, and provides a pharmacologic basis for therapeutic use of i.v. ascorbate
  • H2O2 formation results in selective cytotoxicity
  • Tumor cells are killed with exposure to H2O2 for ≤30 min
  • In vitro, killing is mediated by H2O2 rather than Asc•−
  • In addition to cancer treatment, another potential therapeutic use is for treatment of infections. H2O2 concentrations of 25–50 μM are bacteriostatic
  • virally infected cells may also be candidates
  • Nathan Goodyear on 05 Mar 18
     
    follow up invivo study to previous study from 2005.  Here, the authors prove their hypothesis that ascorbate is a prodrug for delivery of H2O2.
Nathan Goodyear

Attention-Deficit/Hyperactivity Disorder and Urinary Metabolites of Organophosphate Pes... - 0 views

pediatrics.aappublications.org/...e1270.long

ADHD pediatrics children organophosphates environmental toxins pesticides

shared by Nathan Goodyear on 21 Feb 13 - No Cached
  • Nathan Goodyear on 21 Feb 13
     
    No longer a hypothesis, study shows that organophosphate exposure in children contributes to ADHD incidence.
Nathan Goodyear

PsychiatryOnline | The Journal of Neuropsychiatry and Clinical Neurosciences | Can Trau... - 0 views

neuro.psychiatryonline.org/article.aspx

TBI traumatic brain injury psychiatric disorders depression anxiety schizophrenia insomnia

shared by Nathan Goodyear on 16 Feb 12 - No Cached
  • Nathan Goodyear on 16 Feb 12
     
    research, though limited, supports the hypothesis that TBI contributes to psychiatric disorders.
Nathan Goodyear

Obesity induces a phenotypic switch in adipose tissue macrophage polarization - 0 views

www.ncbi.nlm.nih.gov/...PMC1716210

obesity M1 M2 macrophages inflammation insulin resistance weight-loss overweight

shared by Nathan Goodyear on 03 Jan 12 - No Cached
  • Nathan Goodyear on 03 Jan 12
     
    obesity results in shift from M2 macrophages to M1 macrophages.  This results in inflammation and insulin resistance.  This fits the current hypothesis that obesity is in and of itself an inflammatory condition.
Nathan Goodyear

Multiple Sclerosis is not a Disease of the Immune System - 0 views

dl.dropbox.com/...MS_Not_an_Immune_Disease.pdf

MS multiple sclerosis inflammation inflammatory condition disease lipid metabolism autoimmune

shared by Nathan Goodyear on 03 Jan 12 - No Cached
  • Nathan Goodyear on 03 Jan 12
     
    good read on an alternate hypothesis of the pathophysiology of MS. THe author proposes that MS is an inflammatory induced dysfunction of lipid metabolism. This is in contrast to the current held dogma that MS is an autoimmune disease.
Nathan Goodyear

Estrogen and prostate cancer: an eclipsed tru... [J Cell Biochem. 2007] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...17786930

estrogen prostate cancer testosterone hormone hormones aromatase activity androgens

shared by Nathan Goodyear on 16 Sep 13 - No Cached
  • Nathan Goodyear on 16 Sep 13
     
    Just the abstract, but Testosterone to estrogen production through aromatase activity plays role in prostate cancer.  This is due to the lack of correlation in androgens and prostate cancer in the androgen hypothesis.  Estrogen receptors alpha/beta balance equally play a role.  
Nathan Goodyear

Impact of Low Testosterone on Response to Treatment ... [Urology. 2014] - Pub... - 0 views

www.ncbi.nlm.nih.gov/...24726311

ED libido men male hormone hormones low Testosterone T PDE5I phosphodiesterase 5 inhibitors

shared by Nathan Goodyear on 16 Apr 14 - No Cached
  • Nathan Goodyear on 16 Apr 14
     
    Here is where science and particularly conclusions fail the public.  The authors conclusions are that tadalifl improves ED and sexual function irrespective of Testosterone levels.  However, the results say something different.  The group with normal Testosterone responded better versus the low Testosterone group.  This difference didn't reach statistical significance though.  This lack of statistical significance does not exclude the fact that there indeed was a difference.  The authors conlcusions take no part in reporting the whole truth, just that which supports their hypothesis. The diagnosis of low T in this study was < 300 ng/dl
Nathan Goodyear

Postmenopausal circulating levels of 2- and 16α-hydroxyestrone and risk of en... - 0 views

www.ncbi.nlm.nih.gov/...PMC3241553

estrogen metabolism 2-hydroxyestrone 4-hydroxyestrone estrogen metabolites cancer uterine cancer endometrial cancer hormones 2:16alpha-OHE1 2:16

shared by Nathan Goodyear on 07 Oct 15 - No Cached
  • our results do not support the hypothesis that greater metabolism of oestrogen via the 2-OH pathway, relative to the 16α-OH pathway, protects against endometrial cancer. Indeed our results are more suggestive of an increase in risk, rather than a decrease, with higher levels of 2-OHE1
  • women with a higher 2-OHE1 : 16α-OHE1 ratio did not have a decreased risk of endometrial cancer as compared with women with a lower ratio
  • The findings from this first prospective epidemiological study of oestrogen metabolites and endometrial cancer are in line with results from prospective studies on breast cancer, another oestrogen-related cancer. None of the seven studies on breast cancer reported significant associations overall
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  • On the whole, prospective epidemiological data do not support the hypothesis that the 2-hydroxyestrogen pathway is protective, and the 16α-hydroxyestrogen pathway harmful, in hormone-dependent cancers
  • Both 2- and 4-hydroxyestrogens are catecholestrogens, and it has been suggested that catecholestrogens increase risk of oestrogen-mediated cancers through direct genotoxic effects, rather than through stimulation of cell proliferation via binding to oestrogen receptors
  • the evidence is stronger for 4-hydroxyestrogens than for 2-hydroxyestrogens
  • a significant increase in risk of breast cancer with levels of 2-OHE1 has also been reported previously, although it was limited to hormone receptor-negative tumours
  • Nathan Goodyear on 07 Oct 15
     
    2:16 hydroxyestrone ratio not associated with uterine cancer risk.
Nathan Goodyear

A Branched-Chain Amino Acid-Related Metabolic Signature that Differentiates Obese and L... - 0 views

www.ncbi.nlm.nih.gov/...PMC3640280

metabolism insulin resistance high protein diet obesity branched chain overload hypothesis

shared by Nathan Goodyear on 21 Oct 13 - No Cached
  • Nathan Goodyear on 21 Oct 13
     
    Rat study found that High fat and high branch chain amino acid intake long-term leads to insulin resistance.  This occurred through phosphorylation of insulin signaling downstream and differed between lean versus obese individuals.  
Nathan Goodyear

The inflammatory consequences of psychologic stres... [Med Hypotheses. 2006] - PubMed r... - 0 views

www.ncbi.nlm.nih.gov/...16781084

inflammation stress obesity

shared by Nathan Goodyear on 26 Jan 11 - No Cached
  • Nathan Goodyear on 26 Jan 11
     
    Excellent discussion of stress, inflammation, and obesity hypothesis
Nathan Goodyear

Chemical toxins: a hypothesis to explain the globa... [J Altern Complement Med. 2002] -... - 0 views

www.ncbi.nlm.nih.gov/...12006126

chemical toxins obesity overweight

shared by Nathan Goodyear on 06 Apr 11 - No Cached
  • Because the obesity epidemic occurred relatively quickly, it has been suggested that environmental causes instead of genetic factors maybe largely responsible
  • exponential production and usage of synthetic organic and inorganic chemicals. Many of these chemicals are better known for causing weight loss at high levels of exposure but much lower concentrations of these same chemicals have powerful weight-promoting actions.
  • his paper presents a hypothesis that the current level of human exposure to these chemicals may have damaged many of the body's natural weight-control mechanisms. Furthermore, it is posited here that these effects, together with a wide range of additional, possibly synergistic, factors may play a significant role in the worldwide obesity epidemic.
  • Nathan Goodyear on 06 Apr 11
     
    Toxins as chemical cause of obesity problem?
Nathan Goodyear

Does the Immune System Naturally Protect Against Cancer? - 0 views

www.ncbi.nlm.nih.gov/...PMC4026755

cancer immune system

shared by Nathan Goodyear on 18 Apr 18 - No Cached
  • Nathan Goodyear on 18 Apr 18
     
    Great read on the innate and humoral immune systems and the cancer immunosurveillance hypothesis.
Nathan Goodyear

Press-pulse: a novel therapeutic strategy for the metabolic management of cancer | Nutr... - 0 views

nutritionandmetabolism.biomedcentral.com/...s12986-017-0178-2

ketogenic diet ketogenic press-pulse hyperbaric oxygen therapy HBOTnutrition diet cancer HBOT IVC IV vitamin C DCA dichloracetic acid cancer therapy cancer treatment alternative cancer treatment

shared by Nathan Goodyear on 09 Jul 17 - No Cached
mamdouh_hfz liked it
  • A “press” disturbance was considered a chronic environmental stress on all organisms in an ecological community
  • “pulse” disturbances were considered acute events that disrupted biological communities to produce high mortality
  • Neoplasia involving dysregulated cell growth is the biological endpoint of the disease
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  • Data from the American Cancer Society show that the rate of increase in cancer deaths/year (3.4%) was two-fold greater than the rate of increase in new cases/year (1.7%) from 2013 to 2017
  • cancer is predicted to overtake heart disease as the leading cause of death in Western societies
  • cancer can also be recognized as a metabolic disease.
  • glucose is first split into two molecules of pyruvate through the Embden–Meyerhof–Parnas glycolytic pathway in the cytosol
  • Aerobic fermentation, on the other hand, involves the production of lactic acid under normoxic conditions
  • persistent lactic acid production in the presence of adequate oxygen is indicative of abnormal respiration
  • Otto Warburg first proposed that all cancers arise from damage to cellular respiration
  • The Crabtree effect is an artifact of the in vitro environment and involves the glucose-induced suppression of respiration with a corresponding elevation of lactic acid production even under hyperoxic (pO2 = 120–160&nbsp;mmHg) conditions associated with cell culture
  • the Warburg theory of insufficient aerobic respiration remains as the most credible explanation for the origin of tumor cells [2, 37, 51, 52, 53, 54, 55, 56, 57].
  • The main points of Warburg’s theory are; 1) insufficient respiration is the predisposing initiator of tumorigenesis and ultimately cancer, 2) energy through glycolysis gradually compensates for insufficient energy through respiration, 3) cancer cells continue to produce lactic acid in the presence of oxygen, and 4) respiratory insufficiency eventually becomes irreversible
  • Efraim Racker coined the term “Warburg effect”, which refers to the aerobic glycolysis that occurs in cancer cells
  • Warburg clearly demonstrated that aerobic fermentation (aerobic glycolysis) is an effect, and not the cause, of insufficient respiration
  • all tumor cells that have been examined to date contain abnormalities in the content or composition of cardiolipin
  • The evidence supporting Warburg’s original theory comes from a broad range of cancers and is now overwhelming
  • respiratory insufficiency, arising from any number mitochondrial defects, can contribute to the fermentation metabolism seen in tumor cells.
  • data from the nuclear and mitochondrial transfer experiments suggest that oncogene changes are effects, rather than causes, of tumorigenesis
  • Normal mitochondria can suppress tumorigenesis, whereas abnormal mitochondria can enhance tumorigenesis
  • In addition to glucose, cancer cells also rely heavily on glutamine for growth and survival
  • Glutamine is anapleurotic and can be rapidly metabolized to glutamate and then to α-ketoglutarate for entry into the TCA cycle
  • Glucose and glutamine act synergistically for driving rapid tumor cell growth
  • Glutamine metabolism can produce ATP from the TCA cycle under aerobic conditions
  • Amino acid fermentation can generate energy through TCA cycle substrate level phosphorylation under hypoxic conditions
  • Hif-1α stabilization enhances aerobic fermentation
  • targeting glucose and glutamine will deprive the microenvironment of fermentable fuels
  • Although Warburg’s hypothesis on the origin of cancer has created confusion and controversy [37, 38, 39, 40], his hypothesis has never been disproved
  • Warburg referred to the phenomenon of enhanced glycolysis in cancer cells as “aerobic fermentation” to highlight the abnormal production of lactic acid in the presence of oxygen
  • Emerging evidence indicates that macrophages, or their fusion hybridization with neoplastic stem cells, are the origin of metastatic cancer cells
  • Radiation therapy can enhance fusion hybridization that could increase risk for invasive and metastatic tumor cells
  • Kamphorst et al. in showing that pancreatic ductal adenocarcinoma cells could obtain glutamine under nutrient poor conditions through lysosomal digestion of extracellular proteins
  • It will therefore become necessary to also target lysosomal digestion, under reduced glucose and glutamine conditions, to effectively manage those invasive and metastatic cancers that express cannibalism and phagocytosis.
  • Previous studies in yeast and mammalian cells show that disruption of aerobic respiration can cause mutations (loss of heterozygosity, chromosome instability, and epigenetic modifications etc.) in the nuclear genome
  • The somatic mutations and genomic instability seen in tumor cells thus arise from a protracted reliance on fermentation energy metabolism and a disruption of redox balance through excess oxidative stress.
  • According to the mitochondrial metabolic theory of cancer, the large genomic heterogeneity seen in tumor cells arises as a consequence, rather than as a cause, of mitochondrial dysfunction
  • A therapeutic strategy targeting the metabolic abnormality common to most tumor cells should therefore be more effective in managing cancer than would a strategy targeting genetic mutations that vary widely between tumors of the same histological grade and even within the same tumor
  • Tumor cells are more fit than normal cells to survive in the hypoxic niche of the tumor microenvironment
  • Hypoxic adaptation of tumor cells allows for them to avoid apoptosis due to their metabolic reprograming following a gradual loss of respiratory function
  • The high rates of tumor cell glycolysis and glutaminolysis will also make them resistant to apoptosis, ROS, and chemotherapy drugs
  • Despite having high levels of ROS, glutamate-derived from glutamine contributes to glutathione production that can protect tumor cells from ROS
    • Nathan Goodyear
      Nathan Goodyear on 08 Feb 18
       
      reason to eliminate glutamine in cancer patients and even GSH with cancer patients
  • It is clear that adaptability to environmental stress is greater in normal cells than in tumor cells, as normal cells can transition from the metabolism of glucose to the metabolism of ketone bodies when glucose becomes limiting
  • Mitochondrial respiratory chain defects will prevent tumor cells from using ketone bodies for energy
  • glycolysis-dependent tumor cells are less adaptable to metabolic stress than are the normal cells. This vulnerability can be exploited for targeting tumor cell energy metabolism
  • In contrast to dietary energy reduction, radiation and toxic drugs can damage the microenvironment and transform normal cells into tumor cells while also creating tumor cells that become highly resistant to drugs and radiation
  • Drug-resistant tumor cells arise in large part from the damage to respiration in bystander pre-cancerous cells
  • Because energy generated through substrate level phosphorylation is greater in tumor cells than in normal cells, tumor cells are more dependent than normal cells on the availability of fermentable fuels (glucose and glutamine)
  • Ketone bodies and fats are non-fermentable fuels
  • Although some tumor cells might appear to oxidize ketone bodies by the presence of ketolytic enzymes [181], it is not clear if ketone bodies and fats can provide sufficient energy for cell viability in the absence of glucose and glutamine
  • Apoptosis under energy stress is greater in tumor cells than in normal cells
  • A calorie restricted ketogenic diet or dietary energy reduction creates chronic metabolic stress in the body
  • . This energy stress acts as a press disturbance
  • Drugs that target availability of glucose and glutamine would act as pulse disturbances
  • Hyperbaric oxygen therapy can also be considered another pulse disturbance
  • The KD can more effectively reduce glucose and elevate blood ketone bodies than can CR alone making the KD potentially more therapeutic against tumors than CR
  • Campbell showed that tumor growth in rats is greater under high protein (&gt;20%) than under low protein content (&lt;10%) in the diet
  • Protein amino acids can be metabolized to glucose through the Cori cycle
  • The fats in KDs used clinically also contain more medium chain triglycerides
  • Calorie restriction, fasting, and restricted KDs are anti-angiogenic, anti-inflammatory, and pro-apoptotic and thus can target and eliminate tumor cells through multiple mechanisms
  • Ketogenic diets can also spare muscle protein, enhance immunity, and delay cancer cachexia, which is a major problem in managing metastatic cancer
  • GKI values of 1.0 or below are considered therapeutic
  • The GKI can therefore serve as a biomarker to assess the therapeutic efficacy of various diets in a broad range of cancers.
  • It is important to remember that insulin drives glycolysis through stimulation of the pyruvate dehydrogenase complex
  • The water-soluble ketone bodies (D-β-hydroxybutyrate and acetoacetate) are produced largely in the liver from adipocyte-derived fatty acids and ketogenic dietary fat. Ketone bodies bypass glycolysis and directly enter the mitochondria for metabolism to acetyl-CoA
  • Due to mitochondrial defects, tumor cells cannot exploit the therapeutic benefits of burning ketone bodies as normal cells would
  • Therapeutic ketosis with racemic ketone esters can also make it feasible to safely sustain hypoglycemia for inducing metabolic stress on cancer cells
    • Nathan Goodyear
      Nathan Goodyear on 08 Feb 18
       
      Ketones are much more than energy adaptabilit, but actually are therapeutic.
  • ketone bodies can inhibit histone deacetylases (HDAC) [229]. HDAC inhibitors play a role in targeting the cancer epigenome
  • Therapeutic ketosis reduces circulating inflammatory markers, and ketones directly inhibit the NLRP3 inflammasome, an important pro-inflammatory pathway linked to carcinogenesis and an important target for cancer treatment response
  • Chronic psychological stress is known to promote tumorigenesis through elevations of blood glucose, glucocorticoids, catecholamines, and insulin-like growth factor (IGF-1)
  • In addition to calorie-restricted ketogenic diets, psychological stress management involving exercise, yoga, music etc. also act as press disturbances that can help reduce fatigue, depression, and anxiety in cancer patients and in animal models
  • Ketone supplementation has also been shown to reduce anxiety behavior in animal models
  • This physiological state also enhances the efficacy of chemotherapy and radiation therapy, while reducing the side effects
  • lower dosages of chemotherapeutic drugs can be used when administered together with calorie restriction or restricted ketogenic diets (KD-R)
  • Besides 2-DG, a range of other glycolysis inhibitors might also produce similar therapeutic effects when combined with the KD-R including 3-bromopyruvate, oxaloacetate, and lonidamine
    • Nathan Goodyear
      Nathan Goodyear on 08 Feb 18
       
      oxaloacetate is a glycolytic inhibitor, as is doxycycline, and IVC.
  • A synergistic interaction of the KD diet plus radiation was seen
  • It is important to recognize, however, that the radiotherapy used in glioma patients can damage the respiration of normal cells and increase availability of glutamine in the microenvironment, which can increase risk of tumor recurrence especially when used together with the steroid drug dexamethasone
  • Poff and colleagues demonstrated that hyperbaric oxygen therapy (HBOT) enhanced the ability of the KD to reduce tumor growth and metastasis
  • HBOT also increases oxidative stress and membrane lipid peroxidation of GBM cells in vitro
  • The effects of the KD and HBOT can be enhanced with administration of exogenous ketones, which further suppressed tumor growth and metastasis
  • Besides HBOT, intravenous vitamin C and dichloroacetate (DCA) can also be used with the KD to selectively increase oxidative stress in tumor cells
  • Recent evidence also shows that ketone supplementation may enhance or preserve overall physical and mental health
  • Some tumors use glucose as a prime fuel for growth, whereas other tumors use glutamine as a prime fuel [102, 186, 262, 263, 264]. Glutamine-dependent tumors are generally less detectable than glucose-dependent under FDG-PET imaging, but could be detected under glutamine-based PET imaging
  • GBM and use glutamine as a major fuel
  • Many of the current treatments used for cancer management are based on the view that cancer is a genetic disease
  • Emerging evidence indicates that cancer is a mitochondrial metabolic disease that depends on availability of fermentable fuels for tumor cell growth and survival
  • Glucose and glutamine are the most abundant fermentable fuels present in the circulation and in the tumor microenvironment
  • Low-carbohydrate, high fat-ketogenic diets coupled with glycolysis inhibitors will reduce metabolic flux through the glycolytic and pentose phosphate pathways needed for synthesis of ATP, lipids, glutathione, and nucleotides
  • Nathan Goodyear on 09 Jul 17
     
    Cancer is a mitochondrial disease? So says the well published Dr Seyfried. Glucose and glutamine drive cancer growth.
Nathan Goodyear

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease - NEJM - 0 views

www.nejm.org/...NEJMoa1707914

inflammation lipids cholesterol atherothrombosis cardiovascular disease CRP myocardial infarction stroke cardiovascular death

shared by Nathan Goodyear on 05 Sep 17 - No Cached
  • Nathan Goodyear on 05 Sep 17
     
    new study challenges the cholesterol = cardiovascular event story?  Good science asks questions and challenges dogma.  The authors claim the inflammatory hypothesis of atherothrombosis is yet unproven?  Maybe they need to get out and read more.  The point here Is not the drug in question, but the fact that a reduction in inflammation reduced recurrent cardiovascular events independent of cholesterol.
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