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Nathan Goodyear

Interorgan ammonia trafficking in liver disease. - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...19067143

liver disease cirrhosis ammonia muscle Muscle mass

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • Nathan Goodyear on 05 Oct 15
     
    The primary metabolizer of ammonia is the liver; however, in liver failure, muscle mass becomes a second means to metabolize excessive ammonia.
Nathan Goodyear

Branched-chain amino acids increase arterial blood ammonia in spite of enhanced intrins... - 0 views

ajpgi.physiology.org/...G269

BCAA branched chain amino acids NH3 ammonia liver disease cirrhosis alpha-ketoglutarate

shared by Nathan Goodyear on 10 Feb 14 - No Cached
  • Nathan Goodyear on 10 Feb 14
     
    Good review of the effects of BCAA on ammonia metabolism.  BCAA increase intramuscular NH3 production through the production of alpha-ketoglutarate.
Nathan Goodyear

Branched-chain amino acids as a protein- and energy-source in liver cirrhosis. - PubMed... - 0 views

www.ncbi.nlm.nih.gov/...14684176

BCAA branched chain amino acids liver cirrhosis hepatitis ammonia

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • Nathan Goodyear on 05 Oct 15
     
    BCAA for liver cirrhosis to improve ammonia clearance.  Increased glutamine is a means to compensate for the decreased ammonia clearance as well as a means to improve energy balance often present in these clients.  Night time dosing prevents fasting catabolic exacerbations.
Nathan Goodyear

Hyperammonemia-induced depletion of glutamate and branched-chain am... - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...8938556

ammonia NH3 BCCA branched chain amino acids glutamine

shared by Nathan Goodyear on 18 Nov 14 - No Cached
  • Nathan Goodyear on 18 Nov 14
     
    Elevated ammonia depletes glutamate and BCCA in muscle and plasma.  A decrease in BCCA is through an up regulation of glutamine in an attempt to eliminate ammonia.
Nathan Goodyear

Acute hyperammonemia activates branched-chain amino acid catabolism... - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...20614225

ammonia BCCA branched chain amino acids

shared by Nathan Goodyear on 18 Nov 14 - No Cached
  • Nathan Goodyear on 18 Nov 14
     
    elevated ammonia levels reduce BCCA levels and increase glutamine levels in an attempt to eliminate ammonia.
Nathan Goodyear

Microenvironmental ammonia enhances T cell exhaustion in colorectal cancer - ScienceDirect - 0 views

www.sciencedirect.com/...S1550413122005046

TME ammonia T cells tumor microenvironment

shared by Nathan Goodyear on 27 Dec 22 - No Cached
  • Nathan Goodyear on 27 Dec 22
     
    Interesting: mouse model finds ammonia in TME inhibits T cell function.
Nathan Goodyear

Probiotics for patients with hepatic encephalopathy. - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...22071855

cochrane BCAA branched chain amino acids hepatic encephalopathy liver cirrhosis ammonia

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • Nathan Goodyear on 05 Oct 15
     
    cochrane review finds equivical evidence for probiotics in hepatic encephalopathy despite improved ammonia metabolism.
Nathan Goodyear

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

www.clinicalcorrelations.org/?p=3544

BCCA branched chain amino acids liver cirrhosis hepatitis amino acids

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

Branched-chain amino acids and muscle ammoni... [Metab Brain Dis. 2013] - PubMed - NCBI - 0 views

www.ncbi.nlm.nih.gov/...23315357

NH3 muscle brain urea cycle metabolism BCAA branched chain amino acids liver cirrhosis disease

shared by Nathan Goodyear on 10 Feb 14 - No Cached
  • BCAA metabolism may improve muscle net ammonia removal by supplying carbon skeletons for formation of alfa-ketoglutarate that combines with two ammonia molecules to become glutamine
  • Nathan Goodyear on 10 Feb 14
     
    Muscle becomes the primary mode of NH3 metabolism in liver cirrhosis.  The authors here propose that it is via an increase in muscle mass rather than specifically lowering NH3.  In fact, there is an early increase in NH3 production.
Nathan Goodyear

Branched-chain amino acids and ammonia metabolism in liver disease: Therapeutic implica... - 0 views

www.sciencedirect.com/...S0899900713000907

BCAA branched chain amino acids glutamate glutamic acid glutamine alpha-ketoglutarate NH3 ammonia liver disease cirrhosis

shared by Nathan Goodyear on 10 Feb 14 - No Cached
  • Nathan Goodyear on 10 Feb 14
     
    BCAA are low in patients with liver cirrhosis due to increased glutamate production from glutamine.  The addition of BCAA in these patients is not without side effects--increased NH3 production.  The addition of alpha ketoglutarate should alleviate this risk.
Nathan Goodyear

Hepatic Encephalopathy - 0 views

www.clevelandclinicmeded.com/...hepatic-encephalopathy

hepatic encephalopathy liver cirrhosis disease ammonia

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • Nathan Goodyear on 05 Oct 15
     
    Good discussion on the underlying mechanisms, as currently known, that contribute to hepatic encephalopathy.
Nathan Goodyear

Branched-chain amino acids in liver diseases - 0 views

www.ncbi.nlm.nih.gov/...PMC3837260

BCAA branched chain amino acids liver cirrhosis disease

shared by Nathan Goodyear on 05 Oct 15 - No Cached
  • Serum concentrations of BCAAs are decreased, while the concentrations of the aromatic amino acids (AAAs) phenylalanine and tyrosine are increased, in patients with advanced liver diseases, resulting in a low ratio of BCAAs to AAAs, a ratio called the Fischer ratio
  • BCAAs were reported to stimulate the production of hepatocyte growth factor
  • a simplified Fischer ratio, the BCAA to tyrosine ratio (BTR), has been reported useful for predicting serum albumin concentration one year later
  • ...10 more annotations...
  • BCAA supplementation was shown to delay the progression of CCl4-induced chronic liver injury in a rat model by reducing hepatic apoptosis
  • BCAAs promoted hepatocyte regeneration in a rat model of hepatectomy
  • BCAA supplementation for advanced cirrhotic patients improves nutritional status and quality of life
  • BCAAs activate mTOR and subsequently increase the production of eukaryotic initiation factor 4E-binding protein-1 and ribosomal protein S6 kinase, which upregulate the synthesis of albumin
  • BCAAs were shown to improve homeostasis model assessment scores for insulin resistance (HOMA-IR) and beta cell function (HOMA-%B) in patients with chronic liver disease, indicating that BCAAs can ameliorate insulin resistance
  • Several clinical trials have suggested that BCAA supplementation improves the prognosis of cirrhotic patients
  • A low Fischer ratio has been associated with hepatic encephalopathy
  • Treatment with BCAAs may therefore have a beneficial effect on patients with hepatic encephalopathy mainly by compensating decreased ratio of BCAAs to AAAs, but not by reducing serum ammonia levels
  • Two randomized studies also showed that BCAAs did not clearly prevent HE in patients with advanced cirrhosis, although BCAAs prevented the progression of hepatic failure
  • a systematic review with meta-analyses on the effect of oral BCAAs for the treatment of HE was published[66]. The review has revealed that supplementation of oral BCAAs in cirrhotic patients inhibits the manifestation of HE, especially in patients with overt HE rather than those with minimal HE, but showed no effect on the survival of those patients[66]. Thus, oral administration of BCAAs is the treatment of choice in cirrhotic patients with HE
  • Nathan Goodyear on 05 Oct 15
     
    good review of BCAA and liver disease: both mechanisms and therapy.
Nathan Goodyear

The Pharmabiotic Approach to Treat Hyperammonemia - 0 views

www.ncbi.nlm.nih.gov/...PMC5852716

ammonia

shared by Nathan Goodyear on 11 May 20 - No Cached
  • Nathan Goodyear on 11 May 20
     
    Good review of treatment of hyperammonia
Nathan Goodyear

We're Not "DON" Yet: Optimal Dosing and Prodrug Delivery of 6-Diazo-5-oxo-L-norleucine ... - 0 views

www.ncbi.nlm.nih.gov/...PMC6130910

glutamine DON dosing cancer

shared by Nathan Goodyear on 17 Mar 24 - No Cached
  • Glutamine is the most abundant amino acid in blood
  • Rapidly proliferating healthy cells (GI epithelium, lymphocytes) or cells under physiologic stress have increased demand for glutamine
  • Glutamine is transported into cells by one of multiple amino acid transporters (e.g. ASCT2, BOAT2), several of which are thought to be upregulated in cancer cells
  • ...10 more annotations...
  • it is hydrolyzed to glutamate and ammonia by glutaminase (‘glutaminolysis’)
  • Glutamate, produced from glutamine by glutaminase and glutamine amidotransferase activities, may be further metabolized to alpha ketoglutarate and provide a carbon skeleton source for the mitochondrial tricarboxylic acid cycle (TCA cycle)
  • Glutamine-derived glutamate is also involved in the synthesis of the reducing equivalent glutathione, vital to maintaining cellular redox status
  • Many tumors become largely dependent on glutamine to provide carbon and nitrogen building blocks needed for proliferation
  • In cancer model systems, Eagle and colleagues first demonstrated tumor cells in culture require supplementation with exogenous glutamine for efficient proliferation
  • It was subsequently shown that when deprived of glutamine tumor cells undergo apoptosis
  • The most well-characterized oncogene to regulate glutamine metabolism is MYC (9), which enhances glutaminase expression, upregulates glutamine transporters, and enhances glutamine utilization in energy production and biosynthesis
  • Other pro-tumorigenic regulators such as KRAS and mTOR, as well as tumor suppressors (p53, VHL) have also been associated with alterations in glutamine metabolism
  • Tumor cells are highly adaptable and alter nutrient uptake and metabolic networks to resist single agent glutaminase inhibition
  • cells in the microenvironment of several tumor types upregulate glutamine production, thereby enabling tumor cells to escape glutaminase inhibition
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