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Nathan Goodyear

American College of Cardiology Foundation | Journal of the American College of Cardiolo... - 0 views

content.onlinejacc.org/article.aspx

mitochondria oxidative stress heart failure heart

shared by Nathan Goodyear on 19 Mar 13 - No Cached
  • Although currently no drugs that specifically target mitochondrial biogenesis in HF are available, acceleration of this process through adenosine monophosphate–activated kinase (AMPK), endothelial nitric oxide synthase (eNOS), and other pathways may represent a promising therapeutic approach
  • Mitochondrial biogenesis can be enhanced therapeutically with the use of adenosine monophosphate kinase (AMPK) agonists, stimulants of nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway (including phosphodiesteraes type 5 inhibitors), or resveratrol
  • metformin, a commonly used antidiabetic drug that activates AMPK signaling
  • ...10 more annotations...
  • Recent evidence suggests that the eNOS/NO/cGMP pathway is an important activator of mitochondrial biogenesis
  • BH4 (tetrahydrobiopterin) supplementation can prevent eNOS uncoupling and was found to reduce left ventricular hypertrophy
  • folic acid is known to replenish reduced BH4 and has been shown to protect the heart through increased eNOS activity
  • Both folate deficiency and inhibition of BH4 synthesis were associated with reduced mitochondrial number and function
  • Resveratrol, a polyphenol compound responsible for the cardioprotective properties of red wine, was recently identified as a potent stimulator of mitochondrial biogenesis
  • epidemiological studies reveal a reduced risk of cardiovascular disease in premenopausal, but not post-menopausal, women compared with men
  • post-menopausal women
    • Nathan Goodyear
      Nathan Goodyear on 19 Mar 13
       
      I would hypothesis that a change in the predominance of ER expression is one of ER beta to ER alpha: creating a more pro-inflammatory signal.
  • The majority of ROS in the heart appear to come from uncoupling of mitochondrial electron transport chain at the level of complexes I and III
  • Because the majority of ROS in HF comes from mitochondria, these organelles are the primary target of oxidative damage.
  • cardioprotective therapies such as angiotensin-converting enzyme inhibitors and ATII receptor blockers were shown to possess antioxidant properties, although it is not known whether they target mitochondrial ROS directly or indirectly
  • Nathan Goodyear on 19 Mar 13
     
    great review of mitochondrial biogenesis, oxidative stress and heart failure.  
Nathan Goodyear

Diabetes - 0 views

diabetes.diabetesjournals.org/...db16-0530

exercise ampk insulin muscle insulin sensitivity

shared by Nathan Goodyear on 10 Jan 17 - No Cached
  • Nathan Goodyear on 10 Jan 17
     
    exercise increases AMPK to improve insulin sensitivity and glucose uptake in new animal study.
Nathan Goodyear

ScienceDirect.com - Cell Metabolism - Estrogen Receptors and the Metabolic Network - 0 views

www.sciencedirect.com/...S1550413111003123

ER-alpha ER-beta estrogen receptor receptors metabolic syndrome MetS hormone hormones

shared by Nathan Goodyear on 11 Oct 12 - No Cached
  • The pro-opiomelanocortin (POMC) neurons have an anorexigenic action and, when activated, reduce food intake through the release of two peptides, α-melanocyte-stimulating hormone (α-MSH) and cocaine-and-amphetamine-regulated transcripts (CART). The neuropeptide Y (NPY) neurons, on the other hand, release NPY hormone and agouti gene-related protein (AgRP), which prevent the binding of α-MSH to MC3R and MC4R, increasing food intake
  • This suggests that the central anorexic effects of E2 may occur via ERβ
  • The main hypothalamic areas involved in food intake and satiety are the arcuate nucleus (ARC), the lateral hypothalamus (LH), the paraventricular nucleus (PVN), the ventromedial hypothalamus (VMH), and the dorsomedial hypothalamus (DMH)
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  • Leptin is a potent anorexigenic and catabolic hormone secreted by adipose cells that reduces food intake and increases energy expenditure
  • E2 not only modulates leptin receptor mRNA in the ARC and VMH, but also increases hypothalamic sensitivity to leptin, altering peripheral fat distribution
  • ghrelin. It acts on growth hormone secretagogue receptors (GHSR1a) located in the ARC and is a potent stimulator of food intake
  • It thus appears that of the two ERs, ERα plays a predominant role in the CNS regulation of lipid and carbohydrate homeostasis.
  • Both ERs have been identified in the ARC
  • Stimulation of MCH neurons increases food intake and fat accumulation while its inhibition leads to decreased food intake and reduced fat accumulation.
  • Both ERs have been identified in the LH
  • both ERs have been identified in this nucleus
  • The PVN is the region of the hypothalamus with the highest expression of ERβ and is reported to be weakly ERα positive
  • The VMH is ERα regulated
  • Skeletal muscle is responsible for 75% of the insulin-induced glucose uptake in the body
  • GLUT4 is highly expressed in muscle and represents a rate-limiting step in the insulin-induced glucose uptake
  • data suggest that in the physiological range, E2 is beneficial for insulin sensitivity, whereas hypo- or hyperestrogenism is related to insulin resistance
  • In aging female rats, E2 treatment improves glucose homeostasis mainly through its ability to increase muscle GLUT4 content on the cell membrane
  • It is evident that ERα and ERβ have distinct actions and that much more research is needed to clearly identify the function of each receptor in muscle.
  • E2 prevents accumulation of visceral fat, increases central sensitivity to leptin, increases the expression of insulin receptors in adipocytes, and decreases the lipogenic activity of lipoprotein lipase in adipose tissue
  • In rats, ovariectomy increases body weight, intra-abdominal fat, fasting glucose and insulin levels, and insulin resistance followed by decreased phosphorylation of AMPK and its substrate acetyl-CoA carboxylase in adipose tissue
  • decreased adiponectin, PPARγ coactivator-1α (PGC-1α), and uncoupling protein 2 (UCP2) and increased resistin
  • Men with aromatase deficiency have truncal obesity, elevated blood lipids, and severe insulin resistance
  • Although not all studies are in agreement, polymorphisms of ERα in humans have been associated with risk factors for CVDs
  • Human subcutaneous and visceral adipose tissues express both ERα and ERβ, whereas only ERα mRNA has been identified in brown adipose tissue
  • suggesting that ERα is the main regulator of GLUT4 expression in adipose tissue
  • Nathan Goodyear on 11 Oct 12
     
    very nice article that looks at the balance of ER-alpha/ER-beta and their role in metabolic syndrome.  This article discusses the balance of  these receptors are tissue dependent in their effect.  I like their conclusion: "...but these mechanisms will never be completely understood if they are not considered in the context of a whole system.
Nathan Goodyear

Up-regulation of adiponectin by resveratrol: The essential roles of the Akt/FOXO1 and A... - 0 views

www.jbc.org/...jbc.M110.188144

resveratrol adiponectin

shared by Nathan Goodyear on 23 Jan 11 - No Cached
  • Nathan Goodyear on 23 Jan 11
     
    Resveratrol increases adiponectin: very important in obestity treatment, insulin resistance, metabolic syndrome...
Nathan Goodyear

Neuronal protein tyrosine phosphatase 1B deficienc... [Mol Cell Biol. 2009] - PubMed re... - 0 views

www.ncbi.nlm.nih.gov/...19528236

leptin weight loss obesity overweight

shared by Nathan Goodyear on 08 Mar 11 - No Cached
  • the mechanism by which PTP1B regulates adiposity and leptin sensitivity likely involves the coordinated regulation of AMPK in hypothalamus and peripheral tissues.
  • Nathan Goodyear on 08 Mar 11
     
    improved leptin sensitivity leads to weight loss and increased energy expenditure
Nathan Goodyear

Erratum to: Testosterone stimulates glucose uptake and GLUT4 translocation through LKB1... - 0 views

www.ncbi.nlm.nih.gov/...26820143

Testosterone GLUT4 glucose

shared by Nathan Goodyear on 02 Feb 16 - No Cached
  • Nathan Goodyear on 02 Feb 16
     
    Testosterone increases glucose intake through increased GLUT4 translocation and activity.
Nathan Goodyear

Multiple Myeloma Tumor Cells are Selectively Killed by Pharmacologically-dosed Ascorbic... - 0 views

www.ebiomedicine.com/...fulltext

multiple myeloma vitamin C IV vitamin C smoldering myeloma cancer

shared by Nathan Goodyear on 25 Sep 17 - No Cached
  • Recent reports indicate that a certain ROS concentration is required for high-dose vitamin C to induce cytotoxicity in cancer cells.
  • The generation of ascorbyl- and H2O2 radicals by PAA increases ROS stress in cancer cells
  • In this study, we report that PAA is efficacious in killing MM cells in vitro and in vivo models, which generated levels of 20–40 mM ascorbate and 500 nM ascorbyl radicals after intraperitoneal administration of 4 g ascorbate per kilogram of body weight (Chen et al., 2008Chen et al., 2008), in xenograft MM mice
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  • These data suggest that PAA may show a therapeutic advantage to blood cancers vs solid tumors because of the communication between tumor cells and blood plasma
  • These results strongly suggest that the mechanism of PAA killing of MM cells is indeed iron-dependent
  • These results suggest that PAA administration in SMM may be able to prevent progression to symtomatic MM
  • A recent study by Yun and colleagues demonstrated that vitamin C selectively kills KRAS and BRAF mutant colorectal cancer cells by targeting GAPDH, but spares normal cells
  • RAS family genes show the most frequent mutations in MM. KRAS, NRAS and BRAF are mutated in 22%, 20% and 7% of MM samples
  • the disease stage rather than the mutation of RAS and/or BRAF is the major predictive factor for PAA sensitivity in MM treatment
  • Other molecular mechanisms including ATP depletion and ATM-AMPK signaling have been reported to explain PAA-induced cell death
  • our pilot study also suggested that PAA could overcome drug resistance to bortezomib in MM cells
  • Our findings complement reported studies and further address the mechanism of action using clinical samples in which we observed that PAA killed tumor cells with high iron content, suggesting that iron might be the initiator of PAA cytotoxicity
  • combination of PAA with standard therapeutic drugs, such as melphalan, may significantly reduce the dose of melphalan needed
  • Combined treatment of reduced dose melphalan with PAA achieved a significantly longer progression-free survival than the same dose of melphalan alone.
  • These data also suggest that the bone marrow suppression induced by high-dose melphalan can be ameliorated by the combination of PAA with lower dose of melphalan because of the lack of toxicity of PAA on normal cells with low iron content.
  • if creatinine clearance is <30 mL/min, high dose ascorbic acid should be not administrated.
  • In MM preclinical and clinical studies, ascorbate was used as an adjunct drug and showed controversial results (Harvey et al., 2009, Perrone et al., 2009, Held et al., 2013, Sharma et al., 2012, Nakano et al., 2011, Takahashi, 2010, Sharma et al., 2009, Qazilbash et al., 2008). However, none of these tests used pharmacological doses of ascorbate and intravenous administration
  • Multiple myeloma (MM) is a plasma cell neoplasm.
  • Cameron and Pauling reported that high doses of vitamin C increased survival of patients with cancer
  • pharmacologically dosed ascorbic acid (PAA) 50–100 g (Chen et al., 2008, Padayatty et al., 2004, Hoffer et al., 2008, Padayatty et al., 2006, Welsh et al., 2013), administered intravenously, has potent anti-cancer activity and its role as anti-cancer therapy is being studied at the University of Iowa and in other centers
  • In the presence of catalytic metal ions like iron, PAA administered intravenously exerts pro-oxidant effects leading to the formation of highly reactive oxygen species (ROS), resulting in cell death
  • the labile iron pool (LIP) is significantly elevated in MM cells
  • The survival of CD138+ cells in vitro was significantly decreased following PAA treatment in all 9 MM
  • In contrast, no significant change of cell viability was observed in CD138− BM cells from the same patients
  • The same effect of PAA was also observed in the SMM patients
  • no response to PAA was detected in CD138+ cells from the 2 MGUS patients
  • the combination of melphalan plus PAA showed greater tumor burden reduction than each drug alone, suggesting a synergistic activity between these two drugs
  • Both catalase and NAC protect cells from oxidative damage
  • cells pretreated with NAC and catalase became resistant to PAA even at high doses
  • adding deferoxamine (DFO), an iron chelator, to OCI-MY5 cells before PAA treatment was also sufficient to prevent PAA-induced cellular death
  • iron is essential for PAA to achieve its anti-cancer activity
  • PAA induced early necrosis (Fig. 3Fig. 3A, 60 min) followed by late apoptosis
  • results further indicated that PAA induced mitochondria-mediated apoptosis
  • PAA by reacting with LIP and generating ROS induces mitochondria-mediated apoptosis in which AIF1 cleavage is important for cell death.
  • ROS and H2O2 are well known factors mediating PAA-induced cancer cell death
  • PAA was sensitive to all 9 MMs and 2 SMMs
  • Nathan Goodyear on 25 Sep 17
     
    animal study finds high-dose, pharmacologic vitamin C found to kill multiple myeloma cells via pro-oxidant effect found in similar studies in dealing with different cancers.
Nathan Goodyear

Berberine Enhances Chemosensitivity and Induces Apoptosis Through Dose-orchestrated AMP... - 0 views

www.jcancer.org/v08p1679.htm

chemotherapy apoptosis berberine

shared by Nathan Goodyear on 11 Jan 21 - No Cached
  • Nathan Goodyear on 11 Jan 21
     
    Berberine improves chemosensitivity; individually induces apoptosis.
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