For thousands
of years humans consumed fructose amounting to 16–20 grams per day
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shared by Nathan Goodyear on 21 May 13
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Pathway Central: LDL Oxidation in Atherogenesis - 0 views
www.sabiosciences.com/pathway.php
LDL cholesterol oxidized LDL plaque inflammation CVD cardiovascular disease
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Great diagram. This diagram shows the current knowledge of how plaque is formed in arteries. The major point here is the oxidation of LDL and the activation of the innate immune system and resultant inflammatory signaling. In the vast majority of cases, the inflammation is driving this process, not the LDL.
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shared by Nathan Goodyear on 14 Jul 15
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Positive effects of astaxanthin on lipid profiles and oxidative stress in overweight su... - 0 views
www.ncbi.nlm.nih.gov/...21964877
astaxanthin MDA malondialdehyde oxidative stress SOD superoxide disumutase oxidized LDL LDL LDL cholesterol CVD
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shared by Nathan Goodyear on 01 Aug 12
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Obesity - Amelioration of Lipid Abnormalities by [alpha]-Lipoic acid Through Antioxidat... - 0 views
www.nature.com/...oby2011121a.html
ALA alpha-lipoic-acid lipoic acid obesity insulin oxidative stress damage inflammation inflammatory markers cytokine cytokines TNF-alpha IL-6 adiponectin IV intravenous oxidized LDL
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alpha lipoic acid found to improve insulin sensitivity and reduce oxidative stress and inflammatory markers. In this study, IV ALA was given daily for 2 weeks, and the result was reduced oxidized LDL and all other lipids, improved insulin sensitivity, reduced TNF-alpha, IL-6, and 8-iso-prostaglandin, and increased adiponectin.
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shared by Nathan Goodyear on 17 Jan 14
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Young Men With Poor Cardiorespi... [Int J Sport Nutr Exerc Metab. 2013] - PubMed - NCBI - 0 views
www.ncbi.nlm.nih.gov/...24413446
oxidized LDL oxidized LDL low T Testosterone men male hormone hormones
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The two faces of α- and γ-tocopherols: an in ... [J Nutr Biochem. 2011] - Pub... - 0 views
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shared by Nathan Goodyear on 26 Sep 12
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Low Doses of Lipopolysaccharide and Minimally Oxidized Low-Density Lipoprotei... - 0 views
circres.ahajournals.org/...56.full
LPS oxidized LDL inflammation macrophages NF-KappaB AP-1 atherosclerosis CAD
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LPS and minimal oxidized LDL have synergistic effects on inflammatory signaling. Together the two promote inflammatory signaling from macrophages at much lower levels than either one alone. They do this through macrophage NF-KappaB and AP-1 pathways. And this resultant inflammation promotes atherosclerosis. Where does all this start? our diet and our gut.
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Residual adverse changes in arterial endothelial fun... [Ann Med. 2007] - PubMed - NCBI - 0 views
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could the flu vaccine cause a short-term increase in cardiovascular event risk? According to this study yes. So, with a recent study showing no benefit in children and adults, then with this finding of increased arterial dysfunction, increased CRP and fibrinogen, and increased LDL oxidation...why would an adult get the flu vaccine??? The focus should be on what the science shows, not an individuals bias!
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shared by Nathan Goodyear on 03 Jan 12
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M2 macrophages exhibit higher sensitivity to oxLDL-induced lipotoxicity than other mono... - 0 views
www.lipidworld.com/...1476-511X-10-229.pdf
macrophages obesity overweight weight-loss inflammation M2 M1 oxidized LDL
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shared by Nathan Goodyear on 11 Apr 17
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Coenzyme Q10 supplementation reduces oxidative stress and increases antioxidant enzyme ... - 0 views
www.ncbi.nlm.nih.gov/...21996047
CoQ10 cardiovascular disease catalase SOD super oxide dismutase MDA CAD coronary artery disease heart health
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shared by Nathan Goodyear on 16 Sep 13
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Nutrition & Metabolism | Full text | Fructose, insulin resistance, and metabolic dyslip... - 0 views
www.nutritionandmetabolism.com/...5
fructose metabolic syndrome metabolic syndrome insulin resistance obesity nutrition metabolism
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Of key importance is the ability of fructose to by-pass the main regulatory step of glycolysis, the conversion of glucose-6-phosphate to fructose 1,6-bisphosphate, controlled by phosphofructokinase
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Thus, while glucose metabolism is negatively regulated by phosphofructokinase, fructose can continuously enter the glycolytic pathway. Therefore, fructose can uncontrollably produce glucose, glycogen, lactate, and pyruvate, providing both the glycerol and acyl portions of acyl-glycerol molecules. These particular substrates, and the resultant excess energy flux due to unregulated fructose metabolism, will promote the over-production of TG (reviewed in [53]).
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Glycemic excursions and insulin responses were reduced by 66% and 65%, respectively, in the fructose-consuming subjects
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reduction in circulating leptin both in the short and long-term as well as a 30% reduction in ghrelin (an orexigenic gastroenteric hormone) in the fructose group compared to the glucose group.
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Both fat and fructose consumption usually results in low leptin concentrations which, in turn, leads to overeating in populations consuming energy from these particular macronutrients
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the liver takes up dietary fructose rapidly where it can be converted to glycerol-3-phosphate. This substrate favours esterification of unbound FFA to form the TG
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Although fructose does not appear to acutely increase insulin levels, chronic exposure seems to indirectly cause hyperinsulinemia and obesity through other mechanisms. One proposed mechanism involves GLUT5
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If FFA are not removed from tissues, as occurs in fructose fed insulin resistant models, there is an increased energy and FFA flux that leads to the increased secretion of TG
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In these scenarios, where there is excess hepatic fatty acid uptake, synthesis and secretion, 'input' of fats in the liver exceed 'outputs', and hepatic steatosis occurs
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Carbohydrate induced hypertriglycerolemia results from a combination of both TG overproduction, and inadequate TG clearance
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fructose-induced metabolic dyslipidemia is usually accompanied by whole body insulin resistance [100] and reduced hepatic insulin sensitivity
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Excess VLDL secretion has been shown to deliver increased fatty acids and TG to muscle and other tissues, further inducing insulin resistance
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the metabolic effects of fructose occur through rapid utilization in the liver due to the bypassing of the regulatory phosphofructokinase step in glycolysis. This in turn causes activation of pyruvate dehydrogenase, and subsequent modifications favoring esterification of fatty acids, again leading to increased VLDL secretion
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Oxidative stress has often been implicated in the pathology of insulin resistance induced by fructose feeding
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Administration of alpha-lipoic acid (LA) has been shown to prevent these changes, and improve insulin sensitivity
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LA treatment also prevents several deleterious effects of fructose feeding: the increases in cholesterol, TG, activity of lipogenic enzymes, and VLDL secretion
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PPARα is a ligand activated nuclear hormone receptor that is responsible for inducing mitochondrial and peroxisomal β-oxidation
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fructose diets altered the structure and function of VLDL particles causing and increase in the TG: protein ratio
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therefore the higher TG results in a smaller, denser, more atherogenic LDL particle, which contributes to the morbidity of the metabolic disorders associated with insulin resistance
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High fructose, which stimulates VLDL secretion, may initiate the cycle that results in metabolic syndrome long before type 2 diabetes and obesity develop
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A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, disturbs normal hepatic carbohydrate metabolism leading to two major consequences (Figure 2): perturbations in glucose metabolism and glucose uptake pathways, and a significantly enhanced rate of de novo lipogenesis and TG synthesis, driven by the high flux of glycerol and acyl portions of TG molecules coming from fructose catabolism
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shared by Nathan Goodyear on 21 May 13
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Plasma lipoproteins: composition, structure and biochemistry - 0 views
lipidlibrary.aocs.org/...index.htm
apolipoproteins cholesterol VLDL chylomicrons LDL HDL lipoproteins biochemistry
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The most abundant lipid constituents are triacylglycerols, free cholesterol, cholesterol esters and phospholipids (phosphatidylcholine and sphingomyelin especially ), though fat-soluble vitamins and anti-oxidants are also transported in this way
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the lipoprotein aggregates should be described in terms of the different protein components or apoproteins (or 'apolipoproteins'
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these classes can be further refined by improved separation procedures, and intermediate-density lipoproteins (IDL) and subdivisions of the HDL (e.g. HDL1, HDL2, HDL3 and so forth
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Density is determined largely by the relative concentrations of triacylglycerols and proteins and by the diameters of the broadly spherical particles
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Lipoproteins are spherical (VLDL, LDL, HDL) to discoidal (nascent HDL) in shape with a core of non-polar lipids, triacylglycerols and cholesterol esters, and a surface monolayer, ~20Å thick, consisting of apoproteins, phospholipids and non-esterified cholesterol, which serves to present a hydrophobic face to the aqueous phase
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the various lipid components should not be considered as absolute, as they are in a state of constant flux
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the main groups are classified as chylomicrons (CM), very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL), based on the relative densities of the aggregates on ultracentrifugation
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The lipoproteins can be categorised simplistically according to their two main metabolic functions. The principal role of the chylomicrons and VLDL is to transport triacylglycerols ‘forward’ as a source of fatty acids from the intestines or liver to the peripheral tissues. In contrast, the HDL remove excess cholesterol from peripheral tissues and deliver it to the liver for excretion in bile in the form of bile acids (‘reverse cholesterol transport’). While these functions are considered separately here for convenience, it should be recognised that the processes are highly complex and inter-related, and they involve transfer of apoproteins, enzymes and lipid constituents among the heterogeneous mix of all the lipoprotein fractions.
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shared by Nathan Goodyear on 04 Aug 14
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Metabolic endotoxemia: a molecular link between obesity and cardiovascular risk - 0 views
jme.endocrinology-journals.org/...R51.full
metabolic endotoxemia obesity insulin resistance cardiovascular disease LPS inflammation
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The starting point for innate immunity activation is the recognition of conserved structures of bacteria, viruses, and fungal components through pattern-recognition receptors
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TLRs are transmembrane proteins containing extracellular domains rich in leucine repeat sequences and a cytosolic domain homologous to the IL1 receptor intracellular domain
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The major proinflammatory mediators produced by the TLR4 activation in response to endotoxin (LPS) are TNFα, IL1β and IL6, which are also elevated in obese and insulin-resistant patients
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Obesity, high-fat diet, diabetes, and NAFLD are associated with higher gut permeability leading to metabolic endotoxemia.
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LPS promotes hepatic insulin resistance, hypertriglyceridemia, hepatic triglyceride accumulation, and secretion of pro-inflammatory cytokines promoting the progression of fatty liver disease.
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In the endothelium, LPS induces the expression of pro-inflammatory, chemotactic, and adhesion molecules, which promotes atherosclerosis development and progression.
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In the adipose tissue, LPS induces adipogenesis, insulin resistance, macrophage infiltration, oxidative stress, and release of pro-inflammatory cytokines and chemokines.
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the gut microbiota has been recently proposed to be an environmental factor involved in the control of body weight and energy homeostasis by modulating plasma LPS levels
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dietary fats alone might not be sufficient to cause overweight and obesity, suggesting that a bacterially related factor might be responsible for high-fat diet-induced obesity.
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This was accompanied in high-fat-fed mice by a change in gut microbiota composition, with reduction in Bifidobacterium and Eubacterium spp.
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n humans, it was also shown that meals with high-fat and high-carbohydrate content (fast-food style western diet) were able to decrease bifidobacteria levels and increase intestinal permeability and LPS concentrations
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it was demonstrated that, more than the fat amount, its composition was a critical modulator of ME (Laugerette et al. 2012). Very recently, Mani et al. (2013) demonstrated that LPS concentration was increased by a meal rich in saturated fatty acids (SFA), while decreased after a meal rich in n-3 polyunsaturated fatty acids (n-3 PUFA).
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this effect seems to be due to the fact that some SFA (e.g., lauric and mystiric acids) are part of the lipid-A component of LPS and also to n-3 PUFA's role on reducing LPS potency when substituting SFA in lipid-A
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these experimental results suggest a pivotal role of CD14-mediated TLR4 activation in the development of LPS-mediated nutritional changes.
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This suggests a link between gut microbiota, western diet, and obesity and indicates that gut microbiota manipulation can beneficially affect the host's weight and adiposity.
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endotoxemia was independently associated with energy intake but not fat intake in a multivariate analysis
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in vitro that endotoxemia activates pro-inflammatory cytokine/chemokine production via NFκB and MAPK signaling in preadipocytes and decreased peroxisome proliferator-activated receptor γ activity and insulin responsiveness in adipocytes.
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LPS-induced release of glucagon, GH and cortisol, which inhibit glucose uptake, both peripheral and hepatic
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Recent evidence has been linking ME with dyslipidemia, increased intrahepatic triglycerides, development, and progression of alcoholic and nonalcoholic fatty liver disease
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The hepatocytes, rather than hepatic macrophages, are the cells responsible for its clearance, being ultimately excreted in bile
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All the subclasses of plasma lipoproteins can bind and neutralize the toxic effects of LPS, both in vitro (Eichbaum et al. 1991) and in vivo (Harris et al. 1990), and this phenomenon seems to be dependent on the number of phospholipids in the lipoprotein surface (Levels et al. 2001). LDL seems to be involved in LPS clearance, but this antiatherogenic effect is outweighed by its proatherogenic features
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LPS produces hypertriglyceridemia by several mechanisms, depending on LPS concentration. In animal models, low-dose LPS increases hepatic lipoprotein (such as VLDL) synthesis, whereas high-dose LPS decreases lipoprotein catabolism
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When a dose of LPS similar to that observed in ME was infused in humans, a 2.5-fold increase in endothelial lipase was observed, with consequent reduction in total and HDL. This mechanism may explain low HDL levels in ‘ME’ and other inflammatory conditions such as obesity and metabolic syndrome
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It is known that the high-fat diet and the ‘ME’ increase intrahepatic triglyceride accumulation, thus synergistically contributing to the development and progression of alcoholic and NAFLD, from the initial stages characterized by intrahepatic triglyceride accumulation up to chronic inflammation (nonalcoholic steatohepatitis), fibrosis, and cirrhosis
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On the other hand, LPS activates Kupffer cells leading to an increased production of ROS and pro-inflammatory cytokines like TNFα
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high-fat diet mice presented with ME, which positively and significantly correlated with plasminogen activator inhibitor (PAI-1), IL1, TNFα, STAMP2, NADPHox, MCP-1, and F4/80 (a specific marker of mature macrophages) mRNAs
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prebiotic administration reduces intestinal permeability to LPS in obese mice and is associated with decreased systemic inflammation when compared with controls
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Cani et al. also found that high-fat diet mice presented with not only ME but also higher levels of inflammatory markers, oxidative stress, and macrophage infiltration markers
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This suggests that important links between gut microbiota, ME, inflammation, and oxidative stress are implicated in a high-fat diet situation
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high-fat feeding is associated with adipose tissue macrophage infiltration (F4/80-positive cells) and increased levels of chemokine MCP-1, suggesting a strong link between ME, proinflammatory status, oxidative stress, and, lately, increased CV risk
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markers of systemic inflammation such as circulating bacterial endotoxin were elevated in patients with chronic infections and were strong predictors of increased atherosclerotic risk
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As a TLR4 ligand, LPS has been suggested to induce atherosclerosis development and progression, via a TLR4-mediated inflammatory state.
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Nutrition Journal | Full text | Homocysteine and reactive oxygen species in metabolic s... - 0 views
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homocysteine contributes to atherogenesis and CVD via: increased ROS, induces endothelial dysfunction, increases platelete adhesion and thrombosis, increases smooth muscle cell proliferation, endothelial cell cytotoxicity, increases LDL oxidation, vasoconstriction, increased MCP-1 and IL-8, and induces endothelial HMG CoA reductase.
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shared by Nathan Goodyear on 18 Jun 13
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Sex hormone modulation of proinflammatory cytokine and C-reactive protein expression in... - 0 views
joe.endocrinology-journals.org/...217.full.pdf
CRP testosterone inflammation men male hormones cytokines
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shared by Nathan Goodyear on 08 May 13
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Testosterone: a metabolic hormone in health and disease - 0 views
joe.endocrinology-journals.org/...R25.full
male hormone hormones testosterone hypogonadal-obesity-adipocytokine hypothesis
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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
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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
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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
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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
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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
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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
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Non-diabetic men undergoing androgen ablation show increased occurrence of new-onset diabetes and demonstrate elevated insulin levels and worsening glycaemic control
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Prostate cancer patients with pre-existing T2DM show a further deterioration of insulin resistance and worsening of diabetic control following ADT
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The response to testosterone replacement of insulin sensitivity is in part dependent on the androgen receptor (AR)
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Low levels of testosterone have been associated with an atherogenic lipoprotein profile, characterised by high LDL and triglyceride levels
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a positive correlation between serum testosterone and HDL has been reported in both healthy and diabetic men
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GLUT4 and IRS1 were up-regulated in cultured adipocytes and skeletal muscle cells following testosterone treatment at low dose and short-time incubations
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orchidectomy of male Wistar rats and associated testosterone deficiency induced increased absorption of glucose from the intestine
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(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.
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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
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In the Chang human adult liver cell line, insulin receptor mRNA expression was significantly increased following exposure to testosterone
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Testosterone deprivation via castration of male rats led to decreased expression of Glut4 in liver tissue, as well as adipose and muscle
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oestrogen was found to increase the expression of insulin receptors in insulin-resistant HepG2 human liver cell line
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FFA decrease hepatic insulin binding and extraction, increase hepatic gluconeogenesis and increase hepatic insulin resistance.
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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)
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This suggests that testosterone may confer some of its beneficial effects on hepatic lipid metabolism via conversion to E2 and subsequent activation of ERα.
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hypogonadal men exhibiting a reduced lean body mass and an increased fat mass, abdominal or central obesity
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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)
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ADT of prostate cancer patients increased both visceral and subcutaneous abdominal fat in a 12-month prospective observational study (Hamilton et al. 2011)
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Catecholamines are the major lipolysis regulating hormones in man and regulate adipocyte lipolysis through activation of adenylate cyclase to produce cAMP
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deficiency of androgen action decreases lipolysis and is primarily responsible for the induction of obesity (Yanase et al. 2008)
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may be some regional differences in the action of testosterone on subcutaneous and visceral adipose function
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proinflammatory adipocytokines IL1, IL6 and TNFα are increased in obesity with a downstream effect that stimulates liver production of CRP
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observational evidence suggests that IL1β, IL6, TNFα and CRP are inversely associated with serum testosterone levels in patients
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This suggests a role for AR in the metabolic actions of testosterone on fat accumulation and adipose tissue inflammatory response
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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
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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
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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
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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
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shared by Nathan Goodyear on 14 Jan 13
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Low doses of LPS and minimally oxidized LDL cooperatively activate macrophages via NF-k... - 0 views
www.ncbi.nlm.nih.gov/...PMC2904601
metabolic endotoxemia atherosclerosis CVD cardiovascular disease inflammation
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shared by Nathan Goodyear on 14 Jul 15
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Inhibition of low-density lipoprotein oxidation by astaxanthin. - PubMed - NCBI - 0 views
www.ncbi.nlm.nih.gov/...11521685
astaxanthin antioxidant antioxidants oxLDL LDL CVD cardiovascular disease
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The adipose tissue metabolism: role of testosterone and dehydroepiandrosterone. - PubMe... - 0 views
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T inhibits lipid uptake and lipoprotein-lipase (LDL) activity in adipocytes, and stimulates lipolysis
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DHEA stimulates resting metabolic rate (RMR) and lipid oxidation, and enhances glucose disposal, by increasing the expression of GLUT-1 and GLUT-4 on fat cell plasma membrane
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The insulin-like effect of DHEA would be associated to a decrease of plasma insulin concentrations and, thus, to an increase of the molar ratio between lipolytic hormones and insulin
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the fat-reducing effect of both T and DHEA seems to be more evident at the level of visceral adipose tissue
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Testosterone inhibits lipid uptake into adipocytes. Testosterone inhibits lipoprotein lipase. Testosterone stimulated lipolysis. Testosterone inhibits adipocyte differentiation of proginator cells. DHEAs effects are through different mechanisms. Both have a preference for activity with visceral adipose tissue.