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Rojas-Rodriguez R, Price LL, Somogie J, Hauguel-de Mouzon S, Kalhan SC, Catalano PM. Maternal Lipid Metabolism Is Associated With Neonatal Adiposity: A Longitudinal Study. J Clin Endocrinol Metab 2022; 107:e3759-e3768. [PMID: 35686573 PMCID: PMC9387706 DOI: 10.1210/clinem/dgac360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 04/22/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Pregnancy is characterized by progressive decreases in glucose insulin sensitivity. Low insulin sensitivity resulting in hyperglycemia is associated with higher neonatal adiposity. However, less is known regarding lipid metabolism, particularly lipid insulin sensitivity in pregnancy and neonatal adiposity. OBJECTIVE Because higher maternal prepregnancy body mass index is strongly associated with both hyperlipidemia and neonatal adiposity, we aimed to examine the longitudinal changes in basal and clamp maternal lipid metabolism as contributors to neonatal adiposity. METHODS Twelve women planning a pregnancy were evaluated before pregnancy, in early (12-14 weeks), and late (34-36 weeks) gestation. Body composition was estimated using hydrodensitometry. Basal and hyperinsulinemic-euglycemic clamp glucose and glycerol turnover (GLYTO) were measured using 2H2-glucose and 2H5-glycerol and substrate oxidative/nonoxidative metabolism with indirect calorimetry. Total body electrical conductivity was used to estimate neonatal body composition. RESULTS Basal free-fatty acids decreased with advancing gestation (P = 0.0210); however, basal GLYTO and nonoxidative lipid metabolism increased over time (P = 0.0046 and P = 0.0052, respectively). Further, clamp GLYTO and lipid oxidation increased longitudinally over time (P = 0.0004 and P = 0.0238, respectively). There was a median 50% increase and significant positive correlation during both basal and clamp GLYTO from prepregnancy through late gestation. Neonatal adiposity correlated with late pregnancy basal and clamp GLYTO (r = 0.6515, P = 0.0217; and r = 0.6051, P = 0.0371). CONCLUSIONS Maternal prepregnancy and late pregnancy measures of basal and clamp lipid metabolism are highly correlated. Late pregnancy basal and clamp GLYTO are significantly associated with neonatal adiposity and account for ~40% of the variance in neonatal adiposity. These data emphasize the importance of maternal lipid metabolism relating to fetal fat accrual.
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Affiliation(s)
| | - Lori Lyn Price
- Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA 02111, USA
- Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA 02111, USA
| | - Jessica Somogie
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA 02111, USA
| | | | - Satish C Kalhan
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Patrick M Catalano
- Mother Infant Research Institute, Tufts Medical Center, Boston, MA 02111, USA
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Abstract
We aimed to characterize the plasma metabolome of chronic thromboembolic pulmonary hypertension patients using a high-throughput unbiased omics approach. We collected fasting plasma from a peripheral vein in 33 operable chronic thromboembolic pulmonary hypertension patients, 31 healthy controls, and 21 idiopathic pulmonary arterial hypertension patients matched for age, gender, and body mass index. Metabolomic analysis was performed using an untargeted approach (Metabolon Inc. Durham, NC). Of the total of 862 metabolites identified, 362 were different in chronic thromboembolic pulmonary hypertension compared to controls: 178 were higher and 184 were lower. Compared to idiopathic pulmonary arterial hypertension, 147 metabolites were different in chronic thromboembolic pulmonary hypertension: 45 were higher and 102 were lower. The plasma metabolome allowed us to distinguish subjects with chronic thromboembolic pulmonary hypertension and healthy controls with a predictive accuracy of 89%, and chronic thromboembolic pulmonary hypertension versus idiopathic pulmonary arterial hypertension with 80% accuracy. Compared to idiopathic pulmonary arterial hypertension and healthy controls, chronic thromboembolic pulmonary hypertension patients had higher fatty acids and glycerol; while acyl cholines and lysophospholipids were lower. Compared to healthy controls, both idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension patients had increased acyl carnitines, beta-hydroxybutyrate, amino sugars and modified amino acids and nucleosides. The plasma global metabolomic profile of chronic thromboembolic pulmonary hypertension suggests aberrant lipid metabolism characterized by increased lipolysis, fatty acid oxidation, and ketogenesis, concomitant with reduced acyl choline and phospholipid moieties. Future research should investigate the pathogenetic and therapeutic potential of modulating lipid metabolism in chronic thromboembolic pulmonary hypertension.
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Affiliation(s)
- Gustavo A. Heresi
- Department of Pulmonary and Critical Care Medicine, Respiratory Institute, Cleveland, OH, USA
| | - Jacob T. Mey
- Integrative Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - John R. Bartholomew
- Section of Vascular Medicine, Heart and Vascular Institute, Cleveland, OH, USA
| | - Ihab S. Haddadin
- Department of Diagnostic Radiology, Imaging Institute, Cleveland, OH, USA
| | - Adriano R. Tonelli
- Department of Pulmonary and Critical Care Medicine, Respiratory Institute, Cleveland, OH, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland, OH, USA
| | - Raed A. Dweik
- Department of Pulmonary and Critical Care Medicine, Respiratory Institute, Cleveland, OH, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland, OH, USA
| | - John P. Kirwan
- Integrative Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Satish C. Kalhan
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland, OH, USA
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Calkins KL, Thamotharan S, Dai Y, Shin BC, Kalhan SC, Devaskar SU. Early dietary restriction in rats alters skeletal muscle tuberous sclerosis complex, ribosomal s6 and mitogen-activated protein kinase. Nutr Res 2018; 54:93-104. [PMID: 29685622 DOI: 10.1016/j.nutres.2018.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/23/2018] [Accepted: 03/19/2018] [Indexed: 01/18/2023]
Abstract
Intrauterine growth restriction is linked to decreased lean body mass and insulin resistance. The mammalian target of rapamycin (mTOR) regulates muscle mass and glucose metabolism; however, little is known about maternal dietary restriction and skeletal muscle mTOR in offspring. We hypothesized that early dietary restriction would decrease skeletal muscle mass and mTOR in the suckling rat. To test this hypothesis, ab libitum access to food or dietary restriction during gestation followed by postnatal cross-fostering to a dietary-restricted or ad libitum-fed rat dam during lactation generated 4 groups: control (CON), intrauterine dietary restricted (IUDR), postnatal dietary restricted (PNDR), and IUDR+PNDR (IPDR). At day 21, when compared to CON, the IUDR group demonstrated "catchup" growth, but no changes were observed in the mTOR pathway. Despite having less muscle mass than CON and IUDR (P < .001), in IPDR and PNDR rats mTOR remained unchanged. IPDR and PNDR (p)-tuberous sclerosis complex 2 was less than the IUDR group (P < .05). Downstream, IPDR's and PNDR's phosphorylated (p)-ribosomal s6 (rs6)/rs6 was less than that of CON (P < .05). However, male IPDR's and PNDR's p-mitogen activated protein kinase MAPK/MAPK was greater than CON (P < .05) without a change in p90 ribosomal s6 kinase (p90RSK). In contrast, in females, MAPK was unchanged, but IPDR p-p90RSK/p90RSK was less than CON (P = .01). In conclusion, IPDR and PNDR reduced skeletal muscle mass but did not decrease mTOR. In IPDR and PNDR, a reduction in tuberous sclerosis complex 2 may explain why mTOR was unchanged, whereas, in males, an increase in MAPK with a decrease in rs6 may suggest a block in MAPK signaling.
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Affiliation(s)
- Kara L Calkins
- Department of Pediatrics, Division of Neonatology & Developmental Biology, Neonatal Research Center of the UCLA Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095-1752.
| | - Shanthie Thamotharan
- Department of Pediatrics, Division of Neonatology & Developmental Biology, Neonatal Research Center of the UCLA Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095-1752.
| | - Yun Dai
- Department of Pediatrics, Division of Neonatology & Developmental Biology, Neonatal Research Center of the UCLA Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095-1752.
| | - Bo-Chul Shin
- Department of Pediatrics, Division of Neonatology & Developmental Biology, Neonatal Research Center of the UCLA Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095-1752.
| | - Satish C Kalhan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, 9620 Carnegie Ave, Cleveland, OH 44106.
| | - Sherin U Devaskar
- Department of Pediatrics, Division of Neonatology & Developmental Biology, Neonatal Research Center of the UCLA Children's Discovery and Innovation Institute, David Geffen School of Medicine UCLA, 10833 Le Conte Ave, Los Angeles, CA 90095-1752.
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Xu W, Comhair SAA, Janocha AJ, Lara A, Mavrakis LA, Bennett CD, Kalhan SC, Erzurum SC. Arginine metabolic endotypes related to asthma severity. PLoS One 2017; 12:e0183066. [PMID: 28797075 PMCID: PMC5552347 DOI: 10.1371/journal.pone.0183066] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/28/2017] [Indexed: 12/13/2022] Open
Abstract
Aims Arginine metabolism via inducible nitric oxide synthase (iNOS) and arginase 2 (ARG2) is higher in asthmatics than in healthy individuals. We hypothesized that a sub-phenotype of asthma might be defined by the magnitude of arginine metabolism categorized on the basis of high and low fraction of exhaled nitric oxide (FENO). Methods To test this hypothesis, asthmatics (n = 52) were compared to healthy controls (n = 51) for levels of FENO, serum arginase activity, and airway epithelial expression of iNOS and ARG2 proteins, in relation to clinical parameters of asthma inflammation and airway reactivity. In parallel, bronchial epithelial cells were evaluated for metabolic effects of iNOS and ARG2 expression in vitro. Results Asthmatics with high FENO (≥ 35 ppb; 44% of asthmatics) had higher expression of iNOS (P = 0.04) and ARG2 (P = 0.05) in the airway, indicating FENO is a marker of the high arginine metabolic endotype. High FENO asthmatics had the lowest FEV1% (P < 0.001), FEV1/FVC (P = 0.0002) and PC20 (P < 0.001) as compared to low FENO asthmatics or healthy controls. Low FENO asthmatics had near normal iNOS and ARG2 expression (both P > 0.05), and significantly higher PC20 (P < 0.001) as compared to high FENO asthmatics. In vitro studies to evaluate metabolic effects showed that iNOS overexpression and iNOS+ARG2 co-expression in a human bronchial epithelial cell line led to greater reliance on glycolysis with higher rate of pyruvate going to lactate. Conclusions The high FENO phenotype represents a large portion of the asthma population, and is typified by greater arginine metabolism and more severe and reactive asthma.
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Affiliation(s)
- Weiling Xu
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail:
| | - Suzy A. A. Comhair
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Allison J. Janocha
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Abigail Lara
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Lori A. Mavrakis
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Carole D. Bennett
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Satish C. Kalhan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Serpil C. Erzurum
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
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Abstract
One carbon metabolism or methyl transfer, a crucial component of metabolism in all cells and tissues, supports the critical function of synthesis of purines, thymidylate and methylation via multiple methyl transferases driven by the ubiquitous methyl donor s-adenosylmethionine. Serine is the primary methyl donor to the one carbon pool. Intracellular folates and methionine metabolism are the critical components of one carbon transfer. Methionine metabolism requires vitamin B12, B6 as cofactors and is modulated by endocrine signals and is responsive to nutrient intake. Perturbations in one carbon transfer can have profound effects on cell proliferation, growth and function. Epidemiological studies in humans and experimental model have established a strong relationship between impaired fetal growth and the immediate and long term consequences to the health of the offspring. It is speculated that during development, maternal environmental and nutrient influences by their effects on one carbon transfer can impact the health of the mother, impair growth and reprogram metabolism of the fetus, and cause long term morbidity in the offspring. The potential for such effects is underscored by the unique responses in methionine metabolism in the human mother during pregnancy, the absence of transsulfuration activity in the fetus, ontogeny of methionine metabolism in the placenta and the unique metabolism of serine and glycine in the fetus. Dietary protein restriction in animals and marginal protein intake in humans causes characteristic changes in one carbon metabolism. The impact of perturbations in one carbon metabolism on the health of the mother during pregnancy, on fetal growth and the neonate are discussed and their possible mechanism explored.
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Affiliation(s)
- Satish C Kalhan
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Department of Pathobiology, Lerner Research Institute, NE-40, Cleveland Clinic, 9500 Euclid Av, Cleveland, OH, 44195, USA.
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Hendrikx T, Watzenböck ML, Walenbergh SMA, Amir S, Gruber S, Kozma MO, Grabsch HI, Koek GH, Pierik MJ, Staufer K, Trauner M, Kalhan SC, Jonkers D, Hofker MH, Binder CJ, Shiri-Sverdlov R. Low levels of IgM antibodies recognizing oxidation-specific epitopes are associated with human non-alcoholic fatty liver disease. BMC Med 2016; 14:107. [PMID: 27443391 PMCID: PMC4957359 DOI: 10.1186/s12916-016-0652-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/29/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Lipid oxidation of membrane phospholipids is accompanied by the formation of oxidation-specific epitopes (OSE). These epitopes are recognized by specific antibodies and represent danger-associated molecular patterns that are generated during chronic inflammatory processes. In a murine model for hepatic inflammation during non-alcoholic fatty liver disease (NAFLD), increased antibody levels targeting OSE were found to be protective. Here, our aim was to determine an association between OSE-specific antibody titers and NAFLD in humans. METHODS IgM and IgG levels with specificity for various OSE were assessed in the plasma of patients with NAFLD (n = 71) and healthy controls (n = 68). Antibody titers were comprehensively analyzed in patients with NAFLD after classification by histological evaluation of liver biopsies. Statistical analysis was performed to determine significant correlations and odds ratios. To study the specificity for NAFLD, plasma antibody titers were measured in patients with hepatitis C (n = 40) and inflammatory bowel disease (n = 62). RESULTS IgM titers against OSE were lower in patients with NAFLD compared to controls. Further biopsy-based classification of patients with NAFLD did not show any difference in IgM levels. Plasma IgM titers towards the P1 mimotope demonstrated an inverse correlation with markers for obesity, systemic inflammation, and liver damage. In contrast, hepatitis C and increased disease activity during inflammatory bowel disease was not associated with reduced IgM titers. CONCLUSIONS Our data highlight the importance of immune recognition of OSE by IgM antibodies in the pathophysiology of NAFLD.
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Affiliation(s)
- Tim Hendrikx
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands.,Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
| | - Martin L Watzenböck
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
| | - Sofie M A Walenbergh
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - Shahzada Amir
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
| | - Sabrina Gruber
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
| | - Maria Ozsvar Kozma
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
| | - Heike I Grabsch
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - Ger H Koek
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - Marieke J Pierik
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - Katharina Staufer
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria
| | - Michael Trauner
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria
| | - Satish C Kalhan
- Department of Pathobiology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Daisy Jonkers
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - Marten H Hofker
- Department of Pathology & Laboratory Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Christoph J Binder
- Departments of Laboratory Medicine, Surgery, and Internal Medicine III, Division of Gastroenterology And Hepatology, Medical University of Vienna, Vienna, Austria.,Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna, Austria
| | - Ronit Shiri-Sverdlov
- Departments of Molecular Genetics, Pathology, and Internal Medicine, Division of Gastroenterology and Hepatology, School of Nutrition and Translational Research in Metabolism (NUTRIM) and School of Oncology and Developmental Biology (GROW), Maastricht University and Maastricht University Medical Center (MUMC), PO Box 616, 6200 MD, Maastricht, The Netherlands.
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Katre P, Joshi S, Bhat DS, Deshmukh M, Gurav N, Pandit S, Lubree H, Marczewski S, Bennett C, Gruca L, Kalyanaraman K, Naik SS, Yajnik CS, Kalhan SC. Effect of multi-nutrient insufficiency on markers of one carbon metabolism in young women: response to a methionine load. Eur J Clin Nutr 2016; 70:687-93. [PMID: 26373967 PMCID: PMC4794418 DOI: 10.1038/ejcn.2015.155] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [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] [Received: 02/02/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 11/08/2022]
Abstract
BACKGROUND/OBJECTIVES Multi-nutrient insufficiencies as a consequence of nutritional and economic factors are common in India and other developing countries. We have examined the impact of multi-nutrient insufficiency on markers of one carbon (1C) metabolism in the blood, and response to a methionine load in clinically healthy young women. SUBJECTS/METHODS Young women from Pune, India (n=10) and Cleveland, USA (n=13) were studied. Blood samples were obtained in the basal state and following an oral methionine load (50 mg/kg of body weight in orange juice). Plasma concentrations of vitamin B12, folate and B6 were measured in the basal state. The effect of methionine load on the levels of methionine, total homocysteine, cysteine, glutathione and amino acids was examined. RESULTS Indian women were significantly shorter and lighter compared with the American women and had lower plasma concentration of vitamins B12, folate and B6, essential amino acids and glutathione, but higher concentration of total homocysteine. The homocysteine response to methionine load was higher in Indian women. The plasma concentrations of glycine and serine increased in the Indian women after methionine (in juice) load. A significant negative correlation between plasma B6 and homocysteine (r= -0.70), and plasma folate and glycine and serine levels were observed in the Indian group (P<0.05) but not in the American group. CONCLUSIONS Multi-nutrient insufficiency in the Indian women caused unique changes in markers of whole body protein and 1C metabolism. These data would be useful in developing nutrient intervention strategies.
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Affiliation(s)
- P Katre
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - S Joshi
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - D S Bhat
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - M Deshmukh
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - N Gurav
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - S Pandit
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - H Lubree
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - S Marczewski
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - C Bennett
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - L Gruca
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - K Kalyanaraman
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - S S Naik
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - C S Yajnik
- Kamalnayan Bajaj Diabetology Research Centre, King Edward Memorial Hospital Research Centre, Pune, India
| | - S C Kalhan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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Xu W, Ghosh S, Comhair SAA, Asosingh K, Janocha AJ, Mavrakis DA, Bennett CD, Gruca LL, Graham BB, Queisser KA, Kao CC, Wedes SH, Petrich JM, Tuder RM, Kalhan SC, Erzurum SC. Increased mitochondrial arginine metabolism supports bioenergetics in asthma. J Clin Invest 2016; 126:2465-81. [PMID: 27214549 DOI: 10.1172/jci82925] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 04/05/2016] [Indexed: 12/16/2022] Open
Abstract
High levels of arginine metabolizing enzymes, including inducible nitric oxide synthase (iNOS) and arginase (ARG), are typical in asthmatic airway epithelium; however, little is known about the metabolic effects of enhanced arginine flux in asthma. Here, we demonstrated that increased metabolism sustains arginine availability in asthmatic airway epithelium with consequences for bioenergetics and inflammation. Expression of iNOS, ARG2, arginine synthetic enzymes, and mitochondrial respiratory complexes III and IV was elevated in asthmatic lung samples compared with healthy controls. ARG2 overexpression in a human bronchial epithelial cell line accelerated oxidative bioenergetic pathways and suppressed hypoxia-inducible factors (HIFs) and phosphorylation of the signal transducer for atopic Th2 inflammation STAT6 (pSTAT6), both of which are implicated in asthma etiology. Arg2-deficient mice had lower mitochondrial membrane potential and greater HIF-2α than WT animals. In an allergen-induced asthma model, mice lacking Arg2 had greater Th2 inflammation than WT mice, as indicated by higher levels of pSTAT6, IL-13, IL-17, eotaxin, and eosinophils and more mucus metaplasia. Bone marrow transplants from Arg2-deficient mice did not affect airway inflammation in recipient mice, supporting resident lung cells as the drivers of elevated Th2 inflammation. These data demonstrate that arginine flux preserves cellular respiration and suppresses pathological signaling events that promote inflammation in asthma.
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Comhair SAA, McDunn J, Bennett C, Fettig J, Erzurum SC, Kalhan SC. Metabolomic Endotype of Asthma. J Immunol 2015; 195:643-50. [PMID: 26048149 DOI: 10.4049/jimmunol.1500736] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/13/2015] [Indexed: 11/19/2022]
Abstract
Metabolomics, the quantification of small biochemicals in plasma and tissues, can provide insight into complex biochemical processes and enable the identification of biomarkers that may serve as therapeutic targets. We hypothesized that the plasma metabolome of asthma would reveal metabolic consequences of the specific immune and inflammatory responses unique to endotypes of asthma. The plasma metabolomic profiles of 20 asthmatic subjects and 10 healthy controls were examined using an untargeted global and focused metabolomic analysis. Individuals were classified based on clinical definitions of asthma severity or by levels of fraction of exhaled NO (FENO), a biomarker of airway inflammation. Of the 293 biochemicals identified in the plasma, 25 were significantly different among asthma and healthy controls (p < 0.05). Plasma levels of taurine, lathosterol, bile acids (taurocholate and glycodeoxycholate), nicotinamide, and adenosine-5-phosphate were significantly higher in asthmatics compared with healthy controls. Severe asthmatics had biochemical changes related to steroid and amino acid/protein metabolism. Asthmatics with high FENO, compared with those with low FENO, had higher levels of plasma branched-chain amino acids and bile acids. Asthmatics have a unique plasma metabolome that distinguishes them from healthy controls and points to activation of inflammatory and immune pathways. The severe asthmatic and high FENO asthmatic have unique endotypes that suggest changes in NO-associated taurine transport and bile acid metabolism.
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Affiliation(s)
- Suzy A A Comhair
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Cleveland Clinic, Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195
| | | | - Carole Bennett
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Jade Fettig
- Cleveland Clinic, Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195
| | - Serpil C Erzurum
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Cleveland Clinic, Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195; Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Satish C Kalhan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; Cleveland Clinic, Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195;
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Affiliation(s)
- Satish C Kalhan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH
| | - Arnab Ghosh
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
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Kummitha CM, Kalhan SC, Saidel GM, Lai N. Relating tissue/organ energy expenditure to metabolic fluxes in mouse and human: experimental data integrated with mathematical modeling. Physiol Rep 2014; 2:2/9/e12159. [PMID: 25263208 PMCID: PMC4270223 DOI: 10.14814/phy2.12159] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mouse models of human diseases are used to study the metabolic and physiological processes leading to altered whole-body energy expenditure (EE), which is the sum of EE of all body organs and tissues. Isotopic techniques, arterio-venous difference of substrates, oxygen, and blood flow measurements can provide essential information to quantify tissue/organ EE and substrate oxidation. To complement and integrate experimental data, quantitative mathematical model analyses have been applied in the design of experiments and evaluation of metabolic fluxes. In this study, a method is presented to quantify the energy expenditure of the main mouse organs using metabolic flux measurements. The metabolic fluxes and substrate utilization of the main metabolic pathways of energy metabolism in the mouse tissue/organ systems and the whole body are quantified using a mathematical model based on mass and energy balances. The model is composed of six organ/tissue compartments: brain, heart, liver, gastrointestinal tract, muscle, and adipose tissue. Each tissue/organ is described with a distinct system of metabolic reactions. This model quantifies metabolic and energetic characteristics of mice under overnight fasting conditions. The steady-state mass balances of metabolites and energy balances of carbohydrate and fat are integrated with available experimental data to calculate metabolic fluxes, substrate utilization, and oxygen consumption in each tissue/organ. The model serves as a paradigm for designing experiments with the minimal reliable measurements necessary to quantify tissue/organs fluxes and to quantify the contributions of tissue/organ EE to whole-body EE that cannot be easily determined currently.
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Affiliation(s)
- China M Kummitha
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Satish C Kalhan
- Department of Pathobiology, Cleveland Clinic, Lerner Research Institute, Cleveland, Ohio, USA
| | - Gerald M Saidel
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Nicola Lai
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
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12
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Narayan S, Flask CA, Kalhan SC, Wilson DL. Hepatic fat during fasting and refeeding by MRI fat quantification. J Magn Reson Imaging 2014; 41:347-53. [PMID: 24590550 DOI: 10.1002/jmri.24616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 12/03/2013] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To explore the sensitivity of high-field small animal magnetic resonance imaging to dynamic changes in fat content in the liver and to characterize the effect of prandial state on imaging studies of hepatic fat. MATERIALS AND METHODS A total of three timepoints were acquired using asymmetric spin-echo acquisitions for 12 mice with 24-hour spacing. After the first scan, half of the cohort was placed on a water-only diet. The second half of the cohort continued to have access to their high-fat chow. The scans were repeated after 24 hours. All animals were then returned to the high-fat diet, and the scans were again repeated after 24 hours. Fat fraction maps were computed using previously described methods. Regions of interests were manually drawn in the livers and the patterns of the two groups over time were compared. RESULTS Five out of six of the animals in the starved group showed an increase in hepatic fat fraction during the fasting period (average increase 0.54 ± 0.48), which decreased on refeeding. Analysis of variance indicated that the results significantly depended on both the group and the timepoint (P = 0.003). CONCLUSION Fat-water imaging methods are able to measure hepatic fat changes caused by short-term dietary perturbations.
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Affiliation(s)
- Sreenath Narayan
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
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13
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Abstract
One-carbon metabolism, or methyl transfer, is critical for metabolism in all cells, is involved in the synthesis of purines, pyrimidines, in the methylation of numerous substrates, proteins, DNA and RNA, and in the expression of a number of genes. Serine is the primary endogenous methyl donor to the one carbon pool. Perturbations in methyl transfer due to nutrient and hormonal changes can have profound effect on cell function, growth and proliferation. It is postulated that at critical stages in development, nutrient and environmental influences by their effect on methyl transfer can impair fetal growth, reprogram metabolism and cause long-term morbidity in the offspring. The potential for their effects is underscored by the unique gestation-related changes in methyl transfer in healthy women, the late expression of transsulfuration cascade in the fetus and the unique metabolism of glycine and serine in the fetus. Dietary protein restriction in animal models and protein malnutrition in humans causes remarkable changes in the methyl transfer in vivo. Although the specific consequences of perturbation in maternal and fetal methyl transfer remain to be determined, a profound influence is suggested by the demonstrated relationship between maternal folate and B12 insufficiency and metabolic programming.
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Affiliation(s)
- Satish C Kalhan
- Department of Molecular Medicine, Cleveland Clinic, Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
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14
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Bieghs V, Hendrikx T, van Gorp PJ, Verheyen F, Guichot YD, Walenbergh SMA, Jeurissen MLJ, Gijbels M, Rensen SS, Bast A, Plat J, Kalhan SC, Koek GH, Leitersdorf E, Hofker MH, Lütjohann D, Shiri-Sverdlov R. The cholesterol derivative 27-hydroxycholesterol reduces steatohepatitis in mice. Gastroenterology 2013; 144:167-178.e1. [PMID: 23041327 DOI: 10.1053/j.gastro.2012.09.062] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/16/2012] [Accepted: 09/19/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic steatohepatitis is characterized by hepatic steatosis with inflammation. Although steatosis is benign and reversible, inflammation can increase liver damage. Hepatic inflammation has been associated with accumulation of cholesterol in lysosomes of Kupffer cells. 27-Hydroxycholesterol (27HC), a derivative of cholesterol formed by CYP27A1, can mobilize cholesterol from the lysosomes to the cytoplasm. We investigated whether 27HC can change the intracellular distribution cholesterol and reduce hepatic inflammation in mice. METHODS We transplanted bone marrow from irradiated wild-type or Cyp27a1(-/-) mice to mice that do not express the low density lipoprotein receptor (Ldlr(-/-)), which are hyperlipidemic; 9 weeks later, mice were fed either regular chow or a high-fat, high-cholesterol (HFC) diet for 3 months. In a separate experiment, Ldlr(-/-) mice were given subcutaneous injections of 27HC and placed on regular chow or HFC diets for 3 weeks. Blood and liver tissues samples were collected and analyzed for intracellular cholesterol distribution and inflammation. RESULTS In Ldlr(-/-) mice that received bone marrow transplants from Cyp27a1(-/-) mice, lysosomes of Kupfer cells had a greater accumulation of cholesterol than those of mice that received bone marrow from wild-type mice, after the HFC diet. Liver histology and gene expression analyses showed increased inflammation and liver damage in mice given bone marrow transplants from Cyp27a1(-/-) mice and placed on the HFC diet. Administration of 27HC to Ldlr(-/-) mice, following the HFC diet, reduced the accumulation of lysosomal cholesterol and hepatic inflammation, compared with mice that were not given 27HC. CONCLUSIONS Accumulation of cholesterol in lysosomes of Kupfer cells promotes hepatic inflammation in mice. The cholesterol derivative 27HC reduces accumulation of cholesterol in lysosomes and might be used to treat non-alcoholic steatohepatitis.
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Affiliation(s)
- Veerle Bieghs
- Department of Molecular Genetics, Maastricht University, Maastricht, the Netherlands
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15
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Narayan S, Kalhan SC, Wilson DL. Recovery of chemical estimates by field inhomogeneity neighborhood error detection (REFINED): fat/water separation at 7 tesla. J Magn Reson Imaging 2012; 37:1247-53. [PMID: 23023815 DOI: 10.1002/jmri.23826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 08/15/2012] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To reduce swaps in fat-water separation methods, a particular issue on 7 Tesla (T) small animal scanners due to field inhomogeneity, using image postprocessing innovations that detect and correct errors in the B0 field map. MATERIALS AND METHODS Fat-water decompositions and B0 field maps were computed for images of mice acquired on a 7T Bruker BioSpec scanner, using a computationally efficient method for solving the Markov Random Field formulation of the multi-point Dixon model. The B0 field maps were processed with a novel hole-filling method, based on edge strength between regions, and a novel k-means method, based on field-map intensities, which were iteratively applied to automatically detect and reinitialize error regions in the B0 field maps. Errors were manually assessed in the B0 field maps and chemical parameter maps both before and after error correction. RESULTS Partial swaps were found in 6% of images when processed with FLAWLESS. After REFINED correction, only 0.7% of images contained partial swaps, resulting in an 88% decrease in error rate. Complete swaps were not problematic. CONCLUSION Ex post facto error correction is a viable supplement to a priori techniques for producing globally smooth B0 field maps, without partial swaps. With our processing pipeline, it is possible to process image volumes rapidly, robustly, and almost automatically.
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Affiliation(s)
- Sreenath Narayan
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
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16
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Abstract
Methionine and folate are the key components of one carbon metabolism, providing the methyl groups for numerous methyl transferase reactions via the ubiquitous methyl donor, s-adenosyl methionine. Methionine metabolism is responsive to nutrient intake, is regulated by several hormones and requires a number of vitamins (B12, pyridoxine, riboflavin) as co-factors. The critical relationship between perturbations in the mother's methionine metabolism and its impact on fetal growth and development is now becoming evident. The relation of folate intake to fetal teratogenesis has been known for some time. Studies in human pregnancy show a continuous decrease in plasma homocysteine, and an increase in plasma choline concentrations with advancing gestation. A higher rate of transsulfuration of methionine in early gestation and of transmethylation in the 3rd trimester was seen in healthy pregnant women. How these processes are impacted by nutritional, hormonal and other influences in human pregnancy and their effect on fetal growth has not been examined. Isocaloric protein restriction in pregnant rats, resulted in fetal growth restriction and metabolic reprogramming. Isocaloric protein restriction in the non-pregnant rat, resulted in differential expression of a number of genes in the liver, a 50% increase in whole body serine biosynthesis and high rate of transmethylation, suggesting high methylation demands. These responses were associated with a significant decrease in intracellular taurine levels in the liver suggesting a role of cellular osmolarity in the observed metabolic responses. These unique changes in methionine and one carbon metabolism in response to physiological, nutritional and hormonal influences make these processes critical for cellular and organ function and growth.
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Affiliation(s)
- Satish C Kalhan
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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17
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Abstract
Serine is generally classified as a nutritionally nonessential (dispensable) amino acid, but metabolically, serine is indispensible and plays an essential role in several cellular processes. Serine is the major source of one-carbon units for methylation reactions that occur via the generation of S-adenosylmethionine. The regulation of serine metabolism in mammalian tissues is thus of critical importance for the control of methyl group transfer. In addition to the well known role of d-serine in the brain, l-serine has recently been implicated in breast cancer and other tumors due in part to the genomic copy number gain for 3-phosphoglycerate dehydrogenase, the enzyme that controls the entry of glycolytic intermediates into the pathway of serine synthesis. Here, we review recent information regarding the synthesis of serine and the regulation of its metabolism and discuss the role played by phosphoenolpyruvate carboxykinase in this process.
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Affiliation(s)
- Satish C Kalhan
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195, USA.
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18
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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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19
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Dasarathy S, McCullough AJ, Muc S, Schneyer A, Bennett CD, Dodig M, Kalhan SC. Sarcopenia associated with portosystemic shunting is reversed by follistatin. J Hepatol 2011; 54:915-21. [PMID: 21145817 PMCID: PMC3118576 DOI: 10.1016/j.jhep.2010.08.032] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [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] [Received: 05/06/2010] [Revised: 07/15/2010] [Accepted: 08/07/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS The distinct role of portosystemic shunting (PSS) in the pathogenesis of sarcopenia (skeletal muscle loss) that occurs commonly in cirrhosis is unclear. We have previously shown increased expression of myostatin (inhibitor of skeletal muscle mass) in the portacaval anastamosis (PCA) rat model of sarcopenia of PSS. The present study was performed to examine the mechanisms of sarcopenia following PCA. METHODS In PCA and sham operated pair fed control rats, the phenylalanine flooding dose method was used to quantify the fractional and absolute protein synthesis rates in the skeletal muscle over time and in response to follistatin, a myostatin antagonist. The expression of myostatin and markers of satellite cell (myocyte precursors) proliferation and differentiation were quantified by real-time PCR and Western blot analyses. RESULTS The absolute synthesis rate (ASR) was lower at 2, 4, and 6 weeks (p<0.05) and the fractional synthesis rate (FSR) of skeletal muscle protein was significantly lower (p<0.05) at week 2 in the PCA rats compared to control rats. Expression of myostatin was elevated while markers of satellite cell proliferation and differentiation were lower at 4 and 6 weeks after PCA. Follistatin increased skeletal muscle mass, muscle FSR and ASR, decreased expression of myostatin protein, and increased expression of markers of satellite cell function. CONCLUSIONS Sarcopenia associated with PSS is caused by impaired protein synthesis and reduced satellite cell function due to increased myostatin expression. Confirming these alterations in human patients with cirrhosis will provide novel therapeutic targets for sarcopenia of liver disease.
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Affiliation(s)
- Srinivasan Dasarathy
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA.
| | - Arthur J. McCullough
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Sean Muc
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Alan Schneyer
- Department of Reproductive Biology, Baystate Medical Center, University of Massachusetts, Worcester, Massachusetts, USA
| | - Carole D. Bennett
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Milan Dodig
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
| | - Satish C. Kalhan
- Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, OH, USA, Department of Pathobiology, Cleveland Clinic, Cleveland, OH, USA
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Kim J, Saidel GM, Kalhan SC. Regulation of Adipose Tissue Metabolism in Humans: Analysis of Responses to the Hyperinsulinemic-Euglycemic Clamp Experiment. Cell Mol Bioeng 2011; 4:281-301. [PMID: 23646067 DOI: 10.1007/s12195-011-0162-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The suppression of lipolysis is one of the key metabolic responses of the adipose tissue during hyperinsulinemia. The failure to respond and resulting increase in plasma fatty acids could contribute to the development of insulin resistance and perturbations in the fuel homeostasis in the whole body. In this study, a mechanistic, computational model of adipose tissue metabolism in vivo has been enhanced to simulate the physiological responses during hyperinsulinemic-euglycemic clamp experiment in humans. The model incorporates metabolic intermediates and pathways that are important in the fed state. In addition, it takes into account the heterogeneity of triose phosphate pools (glycolytic vs. glyceroneogenic), within the adipose tissue. The model can simulate not only steady-state responses at different insulin levels, but also concentration dynamics of major metabolites in the adipose tissue venous blood in accord with the in vivo data. Simulations indicate that (1) regulation of lipoprotein lipase (LPL) reaction is important when the intracellular lipolysis is suppressed by insulin; (2) intracellular diglyceride levels can affect the regulatory mechanisms; and (3) glyceroneogenesis is the dominant pathway for glycerol-3-phosphate synthesis even in the presence of increased glucose uptake by the adipose tissue. Reduced redox and increased phosphorylation states provide a favorable milieu for glyceroneogenesis in response to insulin. A parameter sensitivity analysis predicts that insulin-stimulated glucose uptake would be more severely affected by impairment of GLUT4 translocation and glycolysis than by impairment of glycogen synthesis and pyruvate oxidation. Finally, simulations predict metabolic responses to altered expression of phosphoenolpyruvate carboxykinase (PEP-CK). Specifically, the increase in the rate of re-esterification of fatty acids observed experimentally with the overexpression of PEPCK in the adipose tissue would be accompanied by the up-regulation of acyl Co-A synthase.
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Affiliation(s)
- Jaeyeon Kim
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA ; Center for Modeling Integrated Metabolic Systems, Case Western Reserve University, Cleveland, OH 44106, USA ; Department of Pathobiology, Lerner Research Institute, NE4-203, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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21
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Kalhan SC, Guo L, Edmison J, Dasarathy S, McCullough AJ, Hanson RW, Milburn M. Plasma metabolomic profile in nonalcoholic fatty liver disease. Metabolism 2011; 60:404-13. [PMID: 20423748 PMCID: PMC2950914 DOI: 10.1016/j.metabol.2010.03.006] [Citation(s) in RCA: 382] [Impact Index Per Article: 29.4] [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: 01/19/2010] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 02/06/2023]
Abstract
The plasma profile of subjects with nonalcoholic fatty liver disease (NAFLD), steatosis, and steatohepatitis (NASH) was examined using an untargeted global metabolomic analysis to identify specific disease-related patterns and to identify potential noninvasive biomarkers. Plasma samples were obtained after an overnight fast from histologically confirmed nondiabetic subjects with hepatic steatosis (n = 11) or NASH (n = 24) and were compared with healthy, age- and sex-matched controls (n = 25). Subjects with NAFLD were obese, were insulin resistant, and had higher plasma concentrations of homocysteine and total cysteine and lower plasma concentrations of total glutathione. Metabolomic analysis showed markedly higher levels of glycocholate, taurocholate, and glycochenodeoxycholate in subjects with NAFLD. Plasma concentrations of long-chain fatty acids were lower and concentrations of free carnitine, butyrylcarnitine, and methylbutyrylcarnitine were higher in NASH. Several glutamyl dipeptides were higher whereas cysteine-glutathione levels were lower in NASH and steatosis. Other changes included higher branched-chain amino acids, phosphocholine, carbohydrates (glucose, mannose), lactate, pyruvate, and several unknown metabolites. Random forest analysis and recursive partitioning of the metabolomic data could separate healthy subjects from NAFLD with an error rate of approximately 8% and separate NASH from healthy controls with an error rate of 4%. Hepatic steatosis and steatohepatitis could not be separated using the metabolomic profile. Plasma metabolomic analysis revealed marked changes in bile salts and in biochemicals related to glutathione in subjects with NAFLD. Statistical analysis identified a panel of biomarkers that could effectively separate healthy controls from NAFLD and healthy controls from NASH. These biomarkers can potentially be used to follow response to therapeutic interventions.
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Affiliation(s)
- Satish C Kalhan
- Department of Pathobiology, Cleveland Clinic, Cleveland, OH 44195, USA.
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22
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Kalhan SC, Uppal SO, Moorman JL, Bennett C, Gruca LL, Parimi PS, Dasarathy S, Serre D, Hanson RW. Metabolic and genomic response to dietary isocaloric protein restriction in the rat. J Biol Chem 2010; 286:5266-77. [PMID: 21147771 DOI: 10.1074/jbc.m110.185991] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We have examined hepatic, genomic, and metabolic responses to dietary protein restriction in the non-pregnant Sprague-Dawley rat. Animals were pair-fed either a 6 or 24% casein-based diet for 7-10 days. At the end of the dietary period, a microarray analysis of the liver was performed, followed by validation of the genes of interest. The rates of appearance of phenylalanine, methionine, serine, and glucose and the contribution of pyruvate to serine and glucose were quantified using tracer methods. Plasma and tissue amino acid levels, enzyme activities, and metabolic intermediates were measured. Protein restriction resulted in significant differential expression of a number of genes involved in cell cycle, cell differentiation, transport, transcription, and metabolic processes. RT-PCR showed that the expression of genes involved in serine biosynthesis and fatty acid oxidation was higher, and those involved in fatty acid synthesis and urea synthesis were lower in the liver of protein-restricted animals. Free serine and glycine levels were higher and taurine levels lower in all tissues examined. Tracer isotope studies showed an ∼50% increase in serine de novo synthesis. Pyruvate was the primary (∼90%) source of serine in both groups. Transmethylation of methionine was significantly higher in the protein-restricted group. This was associated with a higher S-adenosylmethionine/S-adenosylhomocysteine ratio and lower cystathione β-synthase and cystathionine γ-lyase activity. Dietary isocaloric protein restriction results in profound changes in hepatic one-carbon metabolism within a short period. These may be related to high methylation demands placed on the organism and caused by possible changes in cellular osmolarity as a result of the efflux of the intracellular taurine.
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Affiliation(s)
- Satish C Kalhan
- Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio 44195, USA.
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23
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Dasarathy J, Gruca LL, Bennett C, Parimi PS, Duenas C, Marczewski S, Fierro JL, Kalhan SC. Methionine metabolism in human pregnancy. Am J Clin Nutr 2010; 91:357-65. [PMID: 19939983 PMCID: PMC2806892 DOI: 10.3945/ajcn.2009.28457] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Hyperhomocysteinemia during pregnancy, which is a consequence of perturbations in methionine and/or folate metabolism, has been implicated in adverse outcomes such as neural tube defects, preeclampsia, spontaneous abortion, and premature delivery. The adaptive changes in methionine metabolism during pregnancy in humans have not been determined. OBJECTIVE Our objective was to examine the kinetics of methionine and its rate of transsulfuration and transmethylation in healthy women with advancing gestation. DESIGN The whole-body rate of appearance (Ra) of methionine and phenylalanine was measured in healthy pregnant women during the first (n = 10), second (n = 5), and third (n = 10) trimesters of pregnancy. These data were compared with those for nonpregnant women (n = 8). Tracers [1-(13)C]methionine, [C(2)H(3)]methionine, and [(2)H(5)]phenylalanine were administered as prime-constant rate infusions. The effect of enteral high-protein, mixed-nutrient load on tracer-determined variables was also examined. RESULTS In pregnant women, the Ra of phenylalanine was significantly (P < 0.05) lower in the first trimester than in the second and third trimesters and was significantly lower than that in nonpregnant women. A linear positive correlation was evident between gestational age and phenylalanine Ra. The fractional rate and total rate of transsulfuration of methionine was significantly (P < 0.05) higher during the first trimester, whereas the rate of transmethylation was higher during the third trimester. Plasma concentrations of total cysteine and homocysteine were lower during pregnancy. CONCLUSIONS Uncomplicated pregnancy in humans is associated with a higher rate of transsulfuration early in gestation and a higher rate of transmethylation of methionine in late gestation. These data may have implications for understanding the role of methionine and homocysteine in complications of pregnancy and for the nutritional care of pregnant women.
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Affiliation(s)
- Jaividhya Dasarathy
- Department of Family Medicine, Case Western Reserve University School of Medicine at MetroHealth Medical Center, Cleveland, OH, USA
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24
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Hay WW, Raju TN, Higgins RD, Kalhan SC, Devaskar SU. Knowledge gaps and research needs for understanding and treating neonatal hypoglycemia: workshop report from Eunice Kennedy Shriver National Institute of Child Health and Human Development. J Pediatr 2009; 155:612-7. [PMID: 19840614 PMCID: PMC3857033 DOI: 10.1016/j.jpeds.2009.06.044] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/01/2009] [Accepted: 06/22/2009] [Indexed: 11/29/2022]
Affiliation(s)
- William W Hay
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
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Affiliation(s)
- Satish C Kalhan
- Department of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Department of Pathobiology, Lerner Research Institute Cleveland Clinic, Cleveland, OH 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, Gruca LL, Dasarathy S, Kalhan SC. Simultaneous assay of isotopic enrichment and concentration of guanidinoacetate and creatine by gas chromatography-mass spectrometry. Anal Biochem 2009; 395:91-9. [PMID: 19646413 DOI: 10.1016/j.ab.2009.07.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [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] [Received: 06/30/2009] [Revised: 07/23/2009] [Accepted: 07/24/2009] [Indexed: 02/02/2023]
Abstract
A gas chromatography-mass spectrometry (GC-MS) method for the simultaneous measurement of isotopic enrichment and concentration of guanidinoacetate (GAA) and creatine in plasma sample for kinetic studies is reported. The method, based on preparation of the bis(trifluoromethyl)pyrimidine methyl ester derivatives of GAA and creatine, is robust and sensitive. The lowest measurable m(1) and m(3) enrichment for GAA and creatine, respectively, was 0.3%. The calibration curves for measurements of concentration were linear over ranges of 0.5 to 250microM GAA and 2 to 500microM for creatine. The method was reliable for inter- and intraassay precision, accuracy, and linearity. The technique was applied in a healthy adult to determine the in vivo fractional synthesis rate of creatine using primed-constant rate infusion of [1-(13)C]glycine. It was found that isotopic enrichment of GAA reached a plateau by 30min of infusion of [1-(13)C]glycine, indicating either a small pool size or a rapid turnover rate (or both) of GAA. In contrast, the tracer appearance in creatine was slow (slope=0.00097), suggesting a large pool size and a slow rate of synthesis of creatine. This method can be used to estimate the rate of synthesis of creatine in vivo in human and animal studies.
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Affiliation(s)
- Takhar Kasumov
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, OH 44195, USA
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Affiliation(s)
- Jianqi Yang
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4936, USA
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Kalhan SC. Metabolism of methionine in vivo: impact of pregnancy, protein restriction, and fatty liver disease. Nestle Nutr Workshop Ser Pediatr Program 2009; 63:121-31; discussion 131-3, 259-68. [PMID: 19346772 DOI: 10.1159/000209977] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The coexistence of intrauterine and neonatal malnutrition and the development of obesity, type 2 diabetes and related comorbidities have been confirmed in a number of studies in humans and animal models. Data from studies in animals suggest that epigenetic changes as a result of altered methylation of the genomic DNA may be responsible for such metabolic patterning. Methionine, an essential amino acid, plays a critical role in the methyltranferases involved in the methylation by providing the one-carbon units via the methionine transmethylation cycle. Because of its interaction with a number of vitamins (B12, folate, pyridoxine), its regulation by hormones, i.e. insulin and glucagon, and by the changes in redox state, methionine metabolism is effected by nutrient and environmental influences and by altered physiological states. In the present review the impact of human pregnancy, dietary protein restriction and fatty liver disease on methionine metabolism is discussed. The role of methionine in metabolic programming in a commonly used model of intrauterine growth retardation and in propagation of fatty liver disease is briefly described.
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Affiliation(s)
- Satish C Kalhan
- Department of Gastroenterology, Cleveland Clinic, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
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Edmison JM, Kalhan SC, McCullough AJ. Obesity, Hepatic Metabolism and Disease. Nestlé Nutrition Institute Workshop Series: Pediatric Program 2009; 63:163-72; discussion 172-6, 259-68. [DOI: 10.1159/000209980] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Abstract
The synthesis and breakdown of triglycerides in adipose tissue and muscle is a crucial element of energy metabolism because it ensures that adequate fuel is available during starvation. Triglyceride turnover determines the availability of fatty acids for utilization by mammalian tissues, and any dysfunction in this process can lead to alterations in glucose metabolism, insulin resistance and type 2 diabetes. Our understanding of the reactions involved in triglyceride synthesis is currently being reassessed, primarily because of the recently identified role that re-esterification of fatty acids plays in triglyceride deposition and, thus, in controlling fatty-acid availability. Here, we review recent information on triglyceride synthesis and introduce the pathway of glyceroneogenesis as an important and highly regulated source of glyceride-glycerol in adipose tissue.
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Affiliation(s)
- Colleen Nye
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106-3549, USA
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Abstract
Birth and adaptation to extrauterine life involve major shifts in the protein and energy metabolism of the human newborn. These include a shift from a state of continuous supply of nutrients including amino acids from the mother to cyclic periodic oral intake, a change in the redox state of organs, thermogenesis, and a significant change in the mobilization and use of oxidative substrates. The development of safe, stable isotopic tracer methods has allowed the study of protein and amino acid metabolism not only in the healthy newborn but also in those born prematurely and of low birth weight. These studies have identified the unique and quantitative aspects of amino acid/protein metabolism in the neonate, thus contributing to rational nutritional care of these babies. The present review summarizes the contemporary data on some of the significant developments in essential and dispensable amino acids and their relationship to overall protein metabolism. Specifically, the recent data of kinetics of leucine, phenylalanine, glutamine, sulfur amino acid, and threonine and their relation to whole-body protein turnover are presented. Finally, the physiological rationale and the impact of nutrient (amino acids) interventions on the dynamics of protein metabolism are discussed.
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Affiliation(s)
- Satish C Kalhan
- Department of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio 44195, USA.
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Abstract
The rates of transmethylation and transsulfuration of methionine were quantified using [1-(13)C]methionine and [C2H3]methionine tracers in newborn infants born at term gestation and in prematurely born low birth weight infants. Whole body rate of protein breakdown was also measured using [2H5]phenylalanine. The response to enteral formula feeding and parenteral nutrition was examined in full term and prematurely born babies, respectively. The relative rates of appearance of methionine and phenylalanine were comparable to the amino acid composition of mixed body proteins. Rates of transmethylation were high, both in full term infants (fast 32 +/- 14 micromol kg(-1) x h(-1); fed 21.7 +/- 3.2) and in preterm infants (57.2 +/- 14.8). Significant flux through the transsulfuration pathway was evident (full term: fast 6.0 +/- 4.4, fed 4.1 +/- 2.1; preterm: 24.9 +/- 9.9 micromol kg(-1) x h(-1)). Transsulfuration of methionine is evident in the human newborn in the immediate neonatal period, suggesting that cysteine may not be considered a "conditionally" essential amino acid for the neonate. The high rate of transmethylation may reflect the high methylation demand, whereas high rates of transsulfuration in premature babies may be related to high demands for glutathione and to the amounts of methionine in parenteral amino acid mixtures.
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Affiliation(s)
- Biju Thomas
- Department of Pediatrics, MetroHealth Medical Center, Cleveland, Ohio 44109, USA
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Nye CK, Hanson RW, Kalhan SC. Glyceroneogenesis is the dominant pathway for triglyceride glycerol synthesis in vivo in the rat. J Biol Chem 2008; 283:27565-27574. [PMID: 18662986 DOI: 10.1074/jbc.m804393200] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Triglyceride synthesis in mammalian tissues requires glycerol 3-phosphate as the source of triglyceride glycerol. In this study the relative contribution of glyceroneogenesis and glycolysis to triglyceride glycerol synthesis was quantified in vivo in adipose tissue, skeletal muscle, and liver of the rat in response to a chow diet (controls), 48-h fast, and lipogenic (high sucrose) diet. The rate of glyceroneogenesis was quantified using the tritium ([(3)H(2)]O) labeling of body water, and the contribution of glucose, via glycolysis, was determined using a [U-(14)C]glucose tracer. In epididymal and mesenteric adipose tissue of control rats, glyceroneogenesis accounted for approximately 90% of triglyceride glycerol synthesis. Fasting for 48 h did not alter glyceroneogenesis in adipose tissue, whereas the contribution of glucose was negligible. In response to sucrose feeding, the synthesis of triglyceride glycerol via both glyceroneogenesis and glycolysis nearly doubled (versus controls); however, glyceroneogenesis remained quantitatively higher as compared with the contribution of glucose. Enhancement of triglyceride-fatty acid cycling by epinephrine infusion resulted in a higher rate of glyceroneogenesis in adipose tissue, as compared with controls, whereas the contribution of glucose via glycolysis was not measurable. Glyceroneogenesis provided the majority of triglyceride glycerol in the gastrocnemius and soleus. In the liver the fractional contribution of glyceroneogenesis remained constant (approximately 60%) under all conditions and was higher than that of glucose. Thus, glyceroneogenesis, in contrast to glucose, via glycolysis, is quantitatively the predominant source of triglyceride glycerol in adipose tissue, skeletal muscle, and liver of the rat during fasting and high sucrose feeding.
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Affiliation(s)
- Colleen K Nye
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Departments of Gastroenterology and Pathobiology, Cleveland Clinic, Cleveland, Ohio 44195
| | - Richard W Hanson
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Departments of Gastroenterology and Pathobiology, Cleveland Clinic, Cleveland, Ohio 44195
| | - Satish C Kalhan
- Departments of Gastroenterology and Pathobiology, Cleveland Clinic, Cleveland, Ohio 44195; Department of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio 44195.
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Lawton KA, Berger A, Mitchell M, Milgram KE, Evans AM, Guo L, Hanson RW, Kalhan SC, Ryals JA, Milburn MV. Analysis of the adult human plasma metabolome. Pharmacogenomics 2008; 9:383-97. [PMID: 18384253 DOI: 10.2217/14622416.9.4.383] [Citation(s) in RCA: 329] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE It is well established that disease states are associated with biochemical changes (e.g., diabetes/glucose, cardiovascular disease/cholesterol), as are responses to chemical agents (e.g., medications, toxins, xenobiotics). Recently, nontargeted methods have been used to identify the small molecules (metabolites) in a biological sample to uncover many of the biochemical changes associated with a disease state or chemical response. Given that these experimental results may be influenced by the composition of the cohort, in the present study we assessed the effects of age, sex and race on the relative concentrations of small molecules (metabolites) in the blood of healthy adults. METHODS Using gas- and liquid-chromatography in combination with mass spectrometry, a nontargeted metabolomic analysis was performed on plasma collected from an age- and sex-balanced cohort of 269 individuals. RESULTS Of the more than 300 unique compounds that were detected, significant changes in the relative concentration of more than 100 metabolites were associated with age. Many fewer differences were associated with sex and fewer still with race. Changes in protein, energy and lipid metabolism, as well as oxidative stress, were observed with increasing age. Tricarboxylic acid intermediates, creatine, essential and nonessential amino acids, urea, ornithine, polyamines and oxidative stress markers (e.g., oxoproline, hippurate) increased with age. Compounds related to lipid metabolism, including fatty acids, carnitine, beta-hydroxybutyrate and cholesterol, were lower in the blood of younger individuals. By contrast, relative concentrations of dehydroepiandrosterone-sulfate (a proposed antiaging androgen) were lowest in the oldest age group. Certain xenobiotics (e.g., caffeine) were higher in older subjects, possibly reflecting decreases in hepatic cytochrome P450 activity. CONCLUSIONS Our nontargeted analytical approach detected a large number of metabolites, including those that were found to be statistically altered with age, sex or race. Age-associated changes were more pronounced than those related to differences in sex or race in the population group we studied. Age, sex and race can be confounding factors when comparing different groups in clinical studies. Future studies to determine the influence of diet, lifestyle and medication are also warranted.
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Affiliation(s)
- Kay A Lawton
- Metabolon, Inc, 800 Capitola Dr. Suite 1, Durham, NC 27713, USA
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Kalhan SC. Re: "alternative equations for whole-body protein synthesis and for fractional synthetic rates of proteins" by Ramakrishnan (Metabolism 2007;56:1550-60). Metabolism 2008; 57:871; author reply 871-2. [PMID: 18502273 PMCID: PMC2603030 DOI: 10.1016/j.metabol.2008.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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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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Kalhan SC, Bugianesi E, McCullough AJ, Hanson RW, Kelley DE. Estimates of hepatic glyceroneogenesis in type 2 diabetes mellitus in humans. Metabolism 2008; 57:305-12. [PMID: 18249200 PMCID: PMC2270402 DOI: 10.1016/j.metabol.2007.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [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] [Received: 05/08/2006] [Accepted: 10/01/2007] [Indexed: 11/19/2022]
Abstract
Glyceroneogenesis, that is, formation of triglyceride-glycerol from pyruvate, is a critical component of triglyceride fatty acid cycling in vivo. The quantitative contribution of glyceroneogenesis to triglyceride-glycerol and its hormonal regulation have not been examined in humans. We have quantified the contribution of pyruvate to very low-density lipoprotein (VLDL) triglycerides in subjects with type 2 diabetes mellitus using the deuterium labeling of body water technique. Subjects with type 2 diabetes mellitus were studied before and after a 6-month behavioral intervention therapy, during fasting and during a hyperinsulinemic normoglycemic clamp. Response to glucagon infusion was examined in 5 healthy subjects after an overnight fast. Glyceroneogenesis contributed approximately 54% to VLDL triglyceride-glycerol in type 2 diabetes mellitus as compared with approximately 12% contribution of plasma glucose. There was no effect of insulin plus glucose during hyperinsulinemic clamp on glyceroneogenesis even after clinical interventions, when insulin sensitivity had improved. In healthy subjects, the contribution of triosephosphates to plasma VLDL triglycerides was approximately 45%. Glyceroneogenesis, in contrast to glycolysis, is the predominant source of triglyceride-glycerol carbon for VLDL triglycerides in subjects with type 2 diabetes mellitus. The contribution of glyceroneogenesis to triglyceride-glycerol is not affected by short (4 hours) infusion of insulin in type 2 diabetes mellitus.
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Affiliation(s)
- Satish C Kalhan
- Schwartz Center for Nutrition and Metabolism, MetroHealth Center, Cleveland, OH 44109, USA.
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Kalhan SC, McCreedy B, Edmison J, Berger A, Hu Y, Dasarathy S, Hanson RW, McCullough AJ. Identificaiton of Non‐Alcoholic Steatohepatitis (NASH) Using Plasma Metabolome in Humans. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1162.5] [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)
| | | | - John Edmison
- Hepatology and GastroenterologyCleveland ClinicClevelandOH
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Hakimi P, Yang J, Casadesus G, Massillon D, Tolentino-Silva F, Nye CK, Cabrera ME, Hagen DR, Utter CB, Baghdy Y, Johnson DH, Wilson DL, Kirwan JP, Kalhan SC, Hanson RW. Overexpression of the cytosolic form of phosphoenolpyruvate carboxykinase (GTP) in skeletal muscle repatterns energy metabolism in the mouse. J Biol Chem 2007; 282:32844-55. [PMID: 17716967 PMCID: PMC4484620 DOI: 10.1074/jbc.m706127200] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [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: 11/06/2022] Open
Abstract
Transgenic mice, containing a chimeric gene in which the cDNA for phosphoenolpyruvate carboxykinase (GTP) (PEPCK-C) (EC 4.1.1.32) was linked to the alpha-skeletal actin gene promoter, express PEPCK-C in skeletal muscle (1-3 units/g). Breeding two founder lines together produced mice with an activity of PEPCK-C of 9 units/g of muscle (PEPCK-C(mus) mice). These mice were seven times more active in their cages than controls. On a mouse treadmill, PEPCK-C(mus) mice ran up to 6 km at a speed of 20 m/min, whereas controls stopped at 0.2 km. PEPCK-C(mus) mice had an enhanced exercise capacity, with a VO(2max) of 156 +/- 8.0 ml/kg/min, a maximal respiratory exchange ratio of 0.91 +/- 0.03, and a blood lactate concentration of 3.7 +/- 1.0 mm after running for 32 min at a 25 degrees grade; the values for control animals were 112 +/- 21 ml/kg/min, 0.99 +/- 0.08, and 8.1 +/- 5.0 mm respectively. The PEPCK-C(mus) mice ate 60% more than controls but had half the body weight and 10% the body fat as determined by magnetic resonance imaging. In addition, the number of mitochondria and the content of triglyceride in the skeletal muscle of PEPCK-C(mus) mice were greatly increased as compared with controls. PEPCK-C(mus) mice had an extended life span relative to control animals; mice up to an age of 2.5 years ran twice as fast as 6-12-month-old control animals. We conclude that overexpression of PEPCK-C repatterns energy metabolism and leads to greater longevity.
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Affiliation(s)
- Parvin Hakimi
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Jianqi Yang
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Gemma Casadesus
- Departments of Neuroscience, and Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Duna Massillon
- Departments of Nutrition, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Fatima Tolentino-Silva
- Departments of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
- Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Colleen K. Nye
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Marco E. Cabrera
- Departments of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
- Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - David R. Hagen
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Christopher B. Utter
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - Yacoub Baghdy
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - David H. Johnson
- Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - David L. Wilson
- Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
| | - John P. Kirwan
- Department of Gastroenterology/Hepatology and Pathobiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Satish C. Kalhan
- Department of Gastroenterology/Hepatology and Pathobiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195
| | - Richard W. Hanson
- Departments of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4935
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Abstract
BACKGROUND Aggressive parenteral nutrition (PN) including amino acids is recommended for low-birth-weight infants to prevent energy and protein deficit. Their impact on acid-base homeostasis has not been examined. METHODS We investigated the impact of dose and duration of parenteral amino acids, with cysteine, on acid-base parameters in 122 low-birth-weight infants. Premature infants <or=32 weeks, <or=1850 g, and receiving parenteral amino acids at 1.5 g/kg/d for an extended period (>24 hours), or 3 g/kg/d for a short (5 hour), extended (24 hour), or prolonged (3-5 days) duration were included in the study. Data were obtained at age 0-3 days (n = 43) or, when clinically stable, age 3-5 days (n = 49). Data from 30 infants, matched for birth weight and gestational age, receiving PN during the first 5 days after birth were also obtained. Acidosis was defined as pH <7.25. RESULTS Acidosis was evident in all infants between 2 and 5 days after birth. Infants with large patent ductus arteriosus (PDA) exhibited significantly (p < .05) lower pH early, had higher blood urea nitrogen levels (26 +/- 9 vs 18 + 8 mg/dL; p < .05), and had greater weight loss ( approximately 17% of birth weight) when compared with infants without PDA. Gestational age, weight loss, and patent ductus arteriosus accounted for 65% of variance in acidosis. CONCLUSIONS Low-birth-weight infants develop metabolic acidosis between 2 and 5 days after birth, irrespective of dose and duration of parenteral amino acid administration. Careful management of parenteral fluids and comorbidities may lower the incidence of acidosis and promote protein accretion.
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Affiliation(s)
- Pushkaraj Jadhav
- Schwartz Center for Metabolism and Nutrition and Department of Pediatrics, Case Western Reserve University, MetroHealth Medical Center, Cleveland, Ohio, 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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47
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Abstract
Glutamine is a non-essential amino acid that can be synthesized de novo from glutamate. This synthesis can be increased by intravenous infusion of carbon precursors (alpha-ketoglutarate or amino acids) in adults and in infants. The metabolism of glutamine is highly compartmentalized between the splanchnic tissues and the periphery, so that orally administered glutamine is completely metabolized in the splanchnic compartment. Data from studies in adults and children show that plasma levels of glutamine decline during acute stress and illness. Because of its importance in several physiological functions (the demonstrated benefits of supplemental glutamine in adult burns and trauma patients and the inhibitory effect on proteolysis in the skeletal muscle in vitro), it has been suggested that during 'acute stress' the demands of glutamine outweigh its de novo synthesis, resulting in a fall in plasma glutamine levels. As a consequence, glutamine has been considered a 'conditionally essential' amino acid. Because of its instability in solution, glutamine is not routinely added to the parenteral amino acid mixtures. A number of clinical trials of parenteral and enteral supplementation of glutamine have been performed. The outcome measures examined have varied between acute effects and long-term complex clinical events such as mortality and risk of infections. Although acute studies in LBW babies have shown some beneficial effects such as changes in protein metabolism and activation of immune system, these have not been translated into prolonged advantages such as reduction in mortality or in nosocomial infection. The reasons for these differences are discussed.
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Affiliation(s)
- Prabhu S Parimi
- Department of Pediatrics, Case Western Reserve University at MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109-1998, USA.
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48
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Abstract
Much recent attention has been paid to the effect of the fetal environment on not only healthy birth outcomes but also long-term health outcomes, including a role as an antecedent to adult diseases. A major gap in our understanding of these relations, however, is the effect of maternal nutrition and nutrient transport on healthy fetal growth and development. In addition, this gap precludes evidence-based recommendations about how to best feed preterm infants. The biological role of the mother and the effect of her nutritional status on infant feeding extend to postnatal infant feeding practices. Currently, evidence is incomplete about not only the composition of human milk, but also the maternal nutritional needs to support extended lactation and the appropriate nutrient composition of foods that will be used to complement breastfeeding at least through the first year of life. Consequently, a conference, organized by the National Institute of Child Health and Human Development, the National Institutes of Health Office of Dietary Supplements, and the US Department of Agriculture Children's Nutrition Research Center was held to explore current knowledge and develop a research agenda to address maternal nutrition and infant feeding practices. These proceedings contain presentations about the effect of maternal nutrition and the placental environment on fetal growth and birth outcomes, as well as issues pertaining to feeding preterm and full-term infants.
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Affiliation(s)
- Daniel J Raiten
- Office of Prevention Research and International Programs, Endocrinology, Nutrition and Growth Branch, Center for Research on Mothers and Children, DHHS/NIH/NICHD, Bethesda, MD 20892, USA.
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49
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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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50
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Kadrofske MM, Parimi PS, Gruca LL, Kalhan SC. Effect of intravenous amino acids on glutamine and protein kinetics in low-birth-weight preterm infants during the immediate neonatal period. Am J Physiol Endocrinol Metab 2006; 290:E622-30. [PMID: 16263773 PMCID: PMC1783930 DOI: 10.1152/ajpendo.00274.2005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [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] [Indexed: 01/16/2023]
Abstract
Glutamine may be a conditionally essential amino acid in low-birth-weight (LBW) preterm neonates. Exogenously administered amino acids, by providing anaplerotic carbon into the tricarboxylic acid cycle, could result in greater cataplerotic efflux and glutamine de novo synthesis. The effect of dose and duration of amino acid infusion on glutamine and nitrogen (N) kinetics was examined in LBW infants in the period immediately after birth. Preterm neonates (<32 weeks gestation, birth weights 809-1,755 g) were randomized to initially receive either 480 or 960 micromol x kg(-1) x h(-1) of an intravenous amino acid solution for 19-24 hours, followed by a higher or lower amino acid load for either 5 h or 24 h. Glutamine de novo synthesis, leucine N, phenylalanine, and urea kinetics were determined using stable isotopic tracers. An increase in amino acid infusion from 480 to 960 micromol x kg(-1) x h(-1) for 5 h resulted in decreased glutamine de novo synthesis in every neonate (384.4 +/- 38.0 to 368.9 +/- 38.2 micromol x kg(-1) x h(-1), P < 0.01) and a lower whole body rate of proteolysis (P < 0.001) and urea synthesis (P < 0.001). However, when the increased amino acid infusion was extended for 24 h, glutamine de novo synthesis increased (369.7 +/- 92.6 to 483.4 +/- 97.5 micromol x kg(-1) x h(-1), P < 0.001), whole body rate of proteolysis did not change, and urea production increased. Decreasing the amino acid load resulted in a decrease in glutamine rate of appearance (R(a)) and leucine N R(a), but had no effect on phenylalanine R(a). Acutely stressed LBW infants responded to an increase in amino acid load by transiently suppressing whole body rate of glutamine synthesis, proteolysis, and oxidation of protein. The mechanisms of this transient effect on whole body protein/nitrogen metabolism remain unknown.
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Affiliation(s)
- Mark M Kadrofske
- Schwartz Center for Metabolism and Nutrition, MetroHealth Medical Center Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio 44109-1998, USA
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