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Kasumov T, Edmison JM, Dasarathy S, Bennett C, Lopez R, Kalhan SC. Plasma levels of asymmetric dimethylarginine in patients with biopsy-proven nonalcoholic fatty liver disease. Metabolism 2011; 60:776-81. [PMID: 20869086 PMCID: PMC3012158 DOI: 10.1016/j.metabol.2010.07.027] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 07/15/2010] [Accepted: 07/16/2010] [Indexed: 01/12/2023]
Abstract
Asymmetric (ADMA) and symmetric dimethylarginine (SDMA) are produced by breakdown of proteins that have been methylated posttranslationally at an arginine residue. Plasma levels of ADMA are elevated in insulin resistance states. Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance and varying degrees of hepatic dysfunction. Because ADMA is metabolized in the liver, we hypothesized that ADMA levels will be high in patients with NAFLD as a consequence of hepatic dysfunction and insulin resistance. Plasma levels of ADMA, SDMA, total homocysteine, glucose, and insulin were measured in nondiabetic patients with biopsy-proven NAFLD (11 steatosis and 24 nonalcoholic steatohepatitis) and 25 healthy subjects. Plasma ADMA levels were significantly higher (P = .029) in patients with biopsy-proven NAFLD (0.43 ± 0.21 μmol/L) compared with controls (0.34 ± 0.10 μmol/L). However, when adjusted for insulin resistance (homeostasis model assessment), the difference between 2 groups was not evident. Plasma SDMA levels were similar in all 3 groups. Plasma levels of ADMA were positively correlated with plasma total homocysteine levels (P = .003). Plasma levels of SDMA were negatively correlated with estimated glomerular filtration rate (P = .016) and positively correlated with plasma total homocysteine levels (P = .003). The ratio of ADMA/SDMA was positively correlated with body mass index (P = .027). Elevated plasma concentrations of ADMA in biopsy-proven NAFLD were primarily related to insulin resistance. Hepatic dysfunction in NAFLD does not appear to make significant contribution to changes in plasma methylarginine levels.
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Affiliation(s)
- Takhar Kasumov
- Department of Gastroenterology, Cleveland Clinic, Cleveland, OH 44195, USA
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Haus JM, Solomon TPJ, Marchetti CM, Edmison JM, González F, Kirwan JP. Free fatty acid-induced hepatic insulin resistance is attenuated following lifestyle intervention in obese individuals with impaired glucose tolerance. J Clin Endocrinol Metab 2010; 95:323-7. [PMID: 19906790 PMCID: PMC2805494 DOI: 10.1210/jc.2009-1101] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The objective of the study was to examine the effects of an exercise/diet lifestyle intervention on free fatty acid (FFA)-induced hepatic insulin resistance in obese humans. RESEARCH DESIGN AND METHODS Obese men and women (n = 23) with impaired glucose tolerance were randomly assigned to either exercise training with a eucaloric (EU; approximately 1800 kcal; n = 11) or hypocaloric (HYPO; approximately 1300 kcal; n = 12) diet for 12 wk. Hepatic glucose production (HGP; milligrams per kilogram fat-free mass(-1) per minute(-1)) and hepatic insulin resistance were determined using a two-stage sequential hyperinsulinemic (40 mU/m(2) . min(-1)) euglycemic (5.0 mm) clamp with [3-(3)H]glucose. Measures were obtained at basal, during insulin infusion (INS; 120 min), and insulin plus intralipid/heparin infusion (INS/FFA; 300 min). RESULTS At baseline, basal HGP was similar between groups; hyperinsulinemia alone did not completely suppress HGP, whereas INS/FFA exhibited less suppression than INS (EU, 4.6 +/- 0.8, 2.0 +/- 0.5, and 2.6 +/- 0.4; HYPO, 3.8 +/- 0.5, 1.2 +/- 0.3, and 2.3 +/- 0.4, respectively). After the intervention the HYPO group lost more body weight (P < 0.05) and fat mass (P < 0.05). However, both lifestyle interventions reduced hepatic insulin resistance during basal (P = 0.005) and INS (P = 0.001) conditions, and insulin-mediated suppression of HGP during INS was equally improved in both groups (EU: -42 +/- 22%; HYPO: -50 +/- 20%, before vs. after, P = 0.02). In contrast, the ability of insulin to overcome FFA-induced hepatic insulin resistance and HGP was improved only in the HYPO group (EU: -15 +/- 24% vs. HYPO: -58 +/- 19%, P = 0.02). CONCLUSIONS Both lifestyle interventions are effective in reducing hepatic insulin resistance under basal and hyperinsulinemic conditions. However, the reversal of FFA-induced hepatic insulin resistance is best achieved with a combined exercise/caloric-restriction intervention.
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Affiliation(s)
- Jacob M Haus
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
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Dasarathy S, Kasumov T, Edmison JM, Gruca LL, Bennett C, Duenas C, Marczewski S, McCullough AJ, Hanson RW, Kalhan SC. Glycine and urea kinetics in nonalcoholic steatohepatitis in human: effect of intralipid infusion. Am J Physiol Gastrointest Liver Physiol 2009; 297:G567-75. [PMID: 19571235 PMCID: PMC2739817 DOI: 10.1152/ajpgi.00042.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The rates of oxidation of glycine and ureagenesis were quantified in the basal state and in response to an intravenous infusion of intralipid with heparin (IL) in healthy subjects (n = 8) and in subjects with nonalcoholic steatohepatitis (NASH) (n = 6). During fasting, no significant difference in weight-specific rate of appearance (R(a)) of glycine, glycine oxidation, and urea synthesis was observed. Intralipid infusion resulted in a significant increase in plasma beta-hydroxybutyrate in both groups. The correlation between free fatty acids and beta-hydroxybutyrate concentration in plasma was 0.94 in NASH compared with 0.4 in controls, indicating greater hepatic fatty acid oxidation in NASH. Intralipid infusion resulted in a significant decrease in urea synthesis and glycine R(a) in both groups and did not impact glycine oxidation. The fractional contribution of glycine carbon to serine was lower in subjects with NASH before and after IL infusion. In contrast, the fractional contribution of serine carbon to cystathionine was higher in NASH before and following IL infusion. These results suggest that hepatic fatty acid oxidation is higher in NASH compared with controls and that glycine oxidation and urea synthesis are not altered. An increase in oxidative stress, induced by a higher rate of fatty acid oxidation in NASH, may have caused an increase in the contribution of serine to cystathionine to meet the higher demands for glutathione.
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Affiliation(s)
- Srinivasan Dasarathy
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Takhar Kasumov
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - John M. Edmison
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Lourdes L. Gruca
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Carole Bennett
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Clarita Duenas
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Susan Marczewski
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Arthur J. McCullough
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Richard W. Hanson
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Satish C. Kalhan
- Departments of Gastroenterology and Hepatology, and Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland; Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
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Kasumov T, Edmison JM, Bennett C, Dasarathy S, Lopez R, McCullough AJ, Kalhan SC. Asymmetric Dimethylarginine Levels in the Plasma Are Elevated in Non‐Alcoholic Fatty Liver Disease. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.709.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Rocio Lopez
- Quantitative Health ServicesCleveland ClinicClevelandOH
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Edmison JM, McCullough AJ. How good is transjugular liver biopsy for the histological evaluation of liver disease? Nat Clin Pract Gastroenterol Hepatol 2007; 4:306-7. [PMID: 17471276 DOI: 10.1038/ncpgasthep0819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 03/28/2007] [Indexed: 05/15/2023]
Affiliation(s)
- John M Edmison
- Department of Gastroenterology, Cleveland Clinic, Cleveland, OH 44195, USA.
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Dasarathy S, Muc S, Hisamuddin K, Edmison JM, Dodig M, McCullough AJ, Kalhan SC. Altered expression of genes regulating skeletal muscle mass in the portacaval anastomosis rat. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1105-13. [PMID: 17185634 DOI: 10.1152/ajpgi.00529.2006] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined the temporal relationship between portacaval anastomosis (PCA), weight gain, changes in skeletal muscle mass and molecular markers of protein synthesis, protein breakdown, and satellite cell proliferation and differentiation. Male Sprague-Dawley rats with end to side PCA (n=24) were compared with sham-operated pair-fed rats (n=24). Whole body weight, lean body mass, and forelimb grip strength were determined at weekly intervals. The skeletal muscle expression of the ubiquitin proteasome system, myostatin, its receptor (the activin 2B receptor) and its signal, cyclin-dependent kinase inhibitor (CDKI) p21, insulin-like growth factor (IGF)-I and its receptor (IGF-I receptor-alpha), and markers of satellite cell proliferation and differentiation were quantified. PCA rats did not gain body weight and had lower lean body mass, forelimb grip strength, and gastrocnemius muscle weight. The skeletal muscle expression of the mRNA of ubiquitin proteasome components was higher in PCA rats in the first 2 wk followed by a lower expression in the subsequent 2 wk (P<0.01). The mRNA and protein of myostatin, activin 2B receptor, and CDKI p21 were higher, whereas IGF-I and its receptor as well as markers of satellite cell function (proliferating nuclear cell antigen, myoD, myf5, and myogenin) were lower at weeks 3 and 4 following PCA (P < 0.05). We conclude that PCA resulted in uninhibited proteolysis in the initial 2 wk. This was followed by an adaptive response in the later 2 wk consisting of an increased expression of myostatin that may have contributed to reduced muscle protein synthesis, impaired satellite cell function, and lower skeletal muscle mass.
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MESH Headings
- Activin Receptors, Type II/genetics
- Activin Receptors, Type II/metabolism
- Amino Acids/blood
- Animals
- Body Composition
- Body Weight
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Differentiation/genetics
- Cell Proliferation
- Cytokines/blood
- Gene Expression
- Hormones/blood
- Insulin-Like Growth Factor I/genetics
- Insulin-Like Growth Factor I/metabolism
- Male
- Muscle Proteins/biosynthesis
- Muscle Proteins/genetics
- Muscle Strength
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Atrophy/etiology
- Muscular Atrophy/metabolism
- Muscular Atrophy/pathology
- Myogenic Regulatory Factors/genetics
- Myogenic Regulatory Factors/metabolism
- Organ Size
- Portacaval Shunt, Surgical/adverse effects
- Proteasome Endopeptidase Complex/genetics
- Proteasome Endopeptidase Complex/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/metabolism
- Satellite Cells, Skeletal Muscle/metabolism
- Satellite Cells, Skeletal Muscle/pathology
- Time Factors
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Affiliation(s)
- Srinivasan Dasarathy
- Department of Gastroenterology, Cleveland Clinic, Lerner Research Institute and the Cleveland Clinic Lerner College of Medicine, NE40, 9500 Euclid Ave., Cleveland, OH 44195, USA.
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Abstract
PURPOSE OF REVIEW To summarize recent findings of the effects of intravenous amino acids on protein kinetics in low-birth-weight infants and to describe the potential cellular mechanism for these observations. RECENT FINDINGS Amino acids administered intravenously for 3-5 h in infants have been shown to suppress whole-body proteolysis. Recent data in low-birth-weight infants show that an increase in the dose of amino acid caused a suppression of proteolysis, and a decrease in the rate of glutamine and urea synthesis. These responses returned to basal state, however, when the amino acid infusion continued for 20-24 h. Supplementation with glutamine sustained the suppression of proteolysis after 3-5 days. Plasma insulin concentration did not change during the amino acid infusion. Data from studies in adults and from in vitro studies suggest that the amino acids impact protein breakdown and synthesis via the mammalian target of rapamycin pathway, stimulating initiation of translation and suppressing autophagic proteolysis. SUMMARY Intravenous amino acids, by increasing extracellular amino acid concentration, transiently stimulate protein synthesis and suppress protein breakdown. These effects return to basal state when the amino acid infusions are prolonged. The mechanism of this adaptive response remains to be determined.
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Affiliation(s)
- Satish C Kalhan
- Department of Gastroenterology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, Ohio 44195, USA.
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Lennon DP, Edmison JM, Caplan AI. Cultivation of rat marrow-derived mesenchymal stem cells in reduced oxygen tension: effects on in vitro and in vivo osteochondrogenesis. J Cell Physiol 2001; 187:345-55. [PMID: 11319758 DOI: 10.1002/jcp.1081] [Citation(s) in RCA: 330] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Rat mesenchymal stem cells (rMSCs) represent a small portion of the cells in the stromal compartment of bone marrow and have the potential to differentiate into bone, cartilage, fat, and fibrous tissue. These mesenchymal progenitor cells were maintained as primary isolates and as subcultured cells in separate closed modular incubator chambers purged with either 95% air and 5% CO(2) (20% or control oxygen) or 5% oxygen, 5% CO(2), and 90% nitrogen (5% or low oxygen). At first passage, some cells from each oxygen condition were loaded into porous ceramic vehicles and implanted into syngeneic host animals in an in vivo assay for osteochondrogenesis. The remaining cells were continued in vitro in the same oxygen tension as for primary culture or were switched to the alternate condition. The first passage cells were examined for in vitro osteogenesis with assays involving the quantification of alkaline phosphatase activity and calcium and DNA content as well as by von Kossa staining to detect mineralization. Cultures maintained in low oxygen had a greater number of colonies as primary isolates and proliferated more rapidly throughout their time in vitro, as indicated by hemacytometer counts at the end of primary culture and increased DNA values for first passage cells. Moreover, rMSCs cultivated in 5% oxygen produced more bone than cells cultured in 20% oxygen when harvested and loaded into porous ceramic cubes and implanted into syngeneic host animals. Finally, markers for osteogenesis, including alkaline phosphatase activity, calcium content, and von Kossa staining, were elevated in cultures which had been in low oxygen throughout their cultivation time. Expression of these markers was usually increased above basal levels when cells were switched from control to low oxygen at first passage and decreased for cells switched from low to control oxygen. We conclude that rMSCs in culture function optimally in an atmosphere of reduced oxygen that more closely approximates documented in vivo oxygen tension.
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Affiliation(s)
- D P Lennon
- Skeletal Research Center, Case Western Reserve University, Cleveland, Ohio 44106-7080, USA
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