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Nathan Goodyear

Obesity is associated with macrophage accumulation in adipose tissue - 0 views

www.ncbi.nlm.nih.gov/...PMC296995

obesity inflammation overweight weight-loss WAT white adipose tissue M1 macrophages

shared by Nathan Goodyear on 16 Jan 12 - No Cached
  • Nathan Goodyear on 16 Jan 12
     
    obesity is associated with dysfunctional immune response to adipose tissue.  The cause is inflammation from White adipose tissue resultant in increased recruitment of macrophages and resultant further inflammation.  M1 macrophages are the predominate culprit.
Nathan Goodyear

Lowered testosterone in male obesity: Mechanisms, morbidity and management Tang Fui MN,... - 0 views

www.ajandrology.com/article.asp

Testosterone male obesity overweight men hormone hormones low T Low T

shared by Nathan Goodyear on 15 Jan 14 - No Cached
  • The number of overweight people is expected to increase from 937 million in 2005 to 1.35 billion in 2030
  • Similarly the number of obese people is projected to increase from 396 million in 2005 to 573 million in 2030
  • By 2030, China alone is predicted to have more overweight men and women than the traditional market economies combined
  • ...37 more annotations...
  • diacylglycerol O-acyltransferase 2 (DGAT2), mechanistically implicated in this differential storage, [10] is regulated by dihydrotestosterone, [11] suggesting a potential role for androgens to influence the genetic predisposition to either the MHO or MONW phenotype.
  • bariatric surgery achieves 10%-30% long-term weight loss in controlled studies
  • The fact that obese men have lower testosterone compared to lean men has been recognized for more than 30 years
  • Reductions in testosterone levels correlate with the severity of obesity and men
  • epidemiological data suggest that the single most powerful predictor of low testosterone is obesity, and that obesity is a major contributor of the age-associated decline in testosterone levels.
  • healthy ageing by itself is uncommonly associated with marked reductions in testosterone levels
  • obesity blunts this LH rise, obesity leads to hypothalamic-pituitary suppression irrespective of age which cannot be compensated for by physiological mechanisms
  • Reductions in total testosterone levels are largely a consequence of reductions in sex hormone binding globulin (SHBG) due to obesity-associated hyperinsulinemia
  • although controversial, measurement of free testosterone levels may provide a more accurate assessment of androgen status than the (usually preferred) measurement of total testosterone in situations where SHBG levels are outside the reference range
  • SHBG increases with age
  • marked obesity however is associated with an unequivocal reduction of free testosterone levels, where LH and follicle stimulating hormone (FSH) levels are usually low or inappropriately normal, suggesting that the dominant suppression occurs at the hypothalamic-pituitary level
  • adipose tissue, especially when in the inflamed, insulin-resistant state, expresses aromatase which converts testosterone to estradiol (E 2 ). Adipose E 2 in turn may feedback negatively to decrease pituitary gonadotropin secretion
  • diabetic obesity is associated with decreases in circulatory E 2
  • In addition to E 2 , increased visceral fat also releases increased amounts of pro-inflammatory cytokines, insulin and leptin; all of which may inhibit the activity of the HPT axis at multiple levels
  • In the prospective Massachusetts Male Aging Study (MMAS), moving from a non-obese to an obese state resulted in a decline of testosterone levels
  • weight loss, whether by diet or surgery, increases testosterone levels proportional to the amount of weight lost
  • fat is androgen-responsive
  • low testosterone may augment the effects of a hypercaloric diet
  • In human male ex vivo adipose tissue, testosterone decreased adipocyte differentiation by 50%.
  • Testosterone enhances catecholamine-induced lipolysis in vitro and reduces lipoprotein lipase activity and triglyceride uptake in human abdominal adipose tissue in vivo
  • in men with prostate cancer receiving 12 months of androgen deprivation therapy, fat mass increased by 3.4 kg and abdominal VAT by 22%, with the majority of these changes established within 6 months
  • severe sex steroid deficiency can increase fat mass rapidly
  • bidirectional relationship between testosterone and obesity
  • increasing body fat suppresses the HPT axis by multiple mechanisms [30] via increased secretion of pro-inflammatory cytokines, insulin resistance and diabetes; [19],[44] while on the other hand low testosterone promotes further accumulation of total and visceral fat mass, thereby exacerbating the gonadotropin inhibition
  • androgens may play a more significant role in VAT than SAT
  • men undergoing androgen depletion for prostate cancer show more marked increases in visceral compared to subcutaneous fat following treatment
    • Nathan Goodyear
      Nathan Goodyear on 16 Jan 14
       
      Interesting: low T increases VAT, yet T therapy does not reduce VAT, yet T therapy reduces SAT.
  • irisin, derived from muscle, induces brown fat-like properties in rodent white fat
  • androgens can act via the PPARg-pathway [37] which is implicated in the differentiation of precursor fat cells to the energy-consuming phenotype
  • low testosterone may compound the effect of increasing fat mass by making it more difficult for obese men to lose weight via exercise
  • pro-inflammatory cytokines released by adipose tissue may contribute to loss of muscle mass and function, leading to inactivity and further weight gain in a vicious cycle
  • Sarcopenic obesity, a phenotype recapitulated in men receiving ADT for prostate cancer, [55] may not only be associated with functional limitations, but also aggravate the metabolic risks of obesity;
  • observational evidence associating higher endogenous testosterone with reduced loss of muscle mass and crude measures of muscle function in men losing weight
  • genuine reactivation of the HPT axis in obese men requires more substantial weight-loss
  • A number of intervention studies have confirmed that both diet- and surgically-induced weight losses are associated with increased testosterone, with the rise in testosterone generally proportional to the amount of weight lost
  • men, regardless of obesity level, can benefit from the effect of weight loss.
  • inconsistent effect of testosterone on VAT
  • Nathan Goodyear on 15 Jan 14
     
    to be read
Nathan Goodyear

Gut microbiota after gastric bypass in human obesity: increased richness and associatio... - 0 views

ajcn.nutrition.org/...16.abstract

gastric bypass obesity gut microbiota microbiota inflammation WAT white adipose tissue dysbiosis gut

shared by Nathan Goodyear on 26 Jun 13 - No Cached
  • Nathan Goodyear on 26 Jun 13
     
    Not that I am proposing gastric bypass for weight loss.  IN my mind that is like a lobotomy for headache.  But, this study shows the link between gut bacteria and obesity.  This study documented an increase in the expression of certain bacteria types in the gut.   This was associated with increase in white adipose tissue gene expression.  Linking directly the gut and fat.
Nathan Goodyear

Chronic inflammation in fat plays a crucial role in the development of obesity-related ... - 0 views

www.ncbi.nlm.nih.gov/...PMC296998

obesity inflammation overweight weight-loss WAT white adipose tissue macrophages insulin resistance fat

shared by Nathan Goodyear on 16 Jan 12 - No Cached
  • Nathan Goodyear on 16 Jan 12
     
    chronic low-grade inflammation plays role in development of insulin resistance and eventually obesity.  This occurs in White Adipose Tissue
Nathan Goodyear

JCI - Chronic inflammation in fat plays a crucial role in the development of obesity-re... - 0 views

www.jci.org/19451

inflammation obesity overweight WAT adipose tissue fat insulin resistance type II diabetes DM

shared by Nathan Goodyear on 20 Mar 12 - No Cached
  • Nathan Goodyear on 20 Mar 12
     
    how inflammation contributes to obesity.  Nice discussion of the inflammatory signaling that leads to obesity.  This occurs predominately in white adipose tissue WAT.  This leads to insulin resistance and type II DM.
Nathan Goodyear

Race differences in obesity and its relationship to the sex hormone milieu : Hormone Mo... - 0 views

www.degruyter.com/...34F8BE807519B51BD841611C00492B

androgens women men male female hormone hormones Testosterone bioavailable Testosterone obesity

shared by Nathan Goodyear on 24 Nov 14 - No Cached
  • increased abdominal and visceral adipose tissue (VAT) – found in women and marked by low sex hormone binding globulin (SHBG) and high bioavailable testosterone (BT) – is related to the metabolic risk profile
  • In men, increased BT is related to decreased abdominal obesity and a decrease in the metabolic risk profile
  • Nathan Goodyear on 24 Nov 14
     
    Only abstract available here.  Race (black vs white) is associated with changes in obesity effects on adrogenicity, particularly in women.  One wonders if this is a result of other variables i.e.vitamin D.
Nathan Goodyear

Metabolic influences on neuroendocrine regulation of reproduction - 0 views

www.ncbi.nlm.nih.gov/...PMC3898855

metabolism metabolic regulation reproduction Leptin Ghrelin Insulin Kisspeptin GNRH

shared by Nathan Goodyear on 17 Feb 14 - No Cached
  • Energy storage occurs mainly at the level of white adipose tissue, where adipocytes secrete the anorexigenic adipokine leptin
  • humans and laboratory animals with leptin or insulin deficiency or resistance and/or increased ghrelin levels exhibit delayed or absent puberty and frequently display hypogonadotropic hypogonadism, which prevents fertility
  • Ghrelin suppresses pulsatile gonadotropin-releasing hormone (GnRH) release [14,15], thus serving as a signal to suppress reproduction in times of famine
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  • Neuropeptides derived from POMC/CART neurons exert a potent anorectic action, thus decreasing food intake and body weight
  • AgRP and NPY have the opposite (orexigenic) effect, inducing food intake.
  • GnRH neurons have been shown to express insulin receptor mRNA and protein [27] and are activated by insulin
  • Kisspeptins (encoded by KISS1) have been identified in the last decade as the most potent secretagogues of GnRH release.
  • Nathan Goodyear on 17 Feb 14
     
    Good, although brief, discussion of the interaction between metabolism and hormones.  Kisspeptin is a GNRH secreatagogue "upstream".   Insulin, Leptin, and Gherlin can inhibit GNRH through resistance and low levels.  Probably a U shaped graph of optimal activity.
Nathan Goodyear

Effects of estrogen on gene expression profiles in mouse hypothalamus and whi... - 0 views

joe.endocrinology-journals.org/...547.short

obesity overweight glutathione stress oxidative weight loss detoxification

shared by Nathan Goodyear on 02 Nov 11 - No Cached
  • Nathan Goodyear on 02 Nov 11
     
    obesity causes oxidative stress, which depletes glutathione.  Lower weight and increase glutathione
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