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Table of Contents
Vol. 9, No. 4, 2009
Issue release date: June 2009
Section title: Original Paper
Free Access
Pancreatology 2009;9:410–419
(DOI:10.1159/000199436)

Nuclear Magnetic Resonance Spectroscopy-Based Metabolomics of the Fatty Pancreas: Implicating Fat in Pancreatic Pathology

Zyromski N.J.a · Mathur A.a · Gowda G.A.N.b · Murphy C.b · Swartz-Basile D.A.a · Wade T.E.a · Pitt H.A.a · Raftery D.b
aDepartment of Surgery, Indiana University, Indianapolis, Ind., and bDepartment of Chemistry, Purdue University, West Lafayette, Ind., USA
email Corresponding Author

Abstract

Background: Obesity is a worldwide epidemic and a significant risk factor for pancreatic diseases including pancreatitis and pancreatic cancer; the mechanisms underlying this association are unknown. Metabolomics is a powerful new analytical approach for describing the metabolome (compliment of small molecules) of cells, tissue or biofluids at any given time. Our aim was to analyze pancreatic fat content in lean and congenitally obese mice using both metabolomic analysis and conventional chromatography. Methods: The pancreatic fat content of 12 lean (C57BL/6J), 12 obese leptin-deficient (Lepob) and 12 obese hyperleptinemic (Lepdb) mice was evaluated by metabolomic analysis, thin-layer and gas chromatography. Results: Pancreata of congenitally obese mice had significantly more total pancreatic fat, triglycerides and free fatty acids, but significantly less phospholipids and cholesterol than those of lean mice. Metabolomic analysis showed excellent correlation with thin-layer and gas chromatography in measuring total fat, triglycerides and phospholipids. Conclusions: Differences in pancreatic fat content and character may have important implications when considering the local pancreatic proinflammatory milieu in obesity. Metabolomic analysis is a valid, powerful tool with which to further define the mechanisms by which fat impacts pancreatic disease.

© 2009 S. Karger AG, Basel and IAP


  

Key Words

  • Obesity
  • Inflammation
  • Metabolomics
  • Pancreatitis
  • Pancreatic cancer

References

  1. Farrell GC, Larter CZ: Nonalcoholic fatty liver disease: from steatosis to cirrhosis. Hepatology 2006;43:S99–S112.
  2. Goldblatt MI, Swartz-Basile DA, Al-Azzawi HH, Tran KQ, Nakeeb A, Pitt HA: Nonalcoholic fatty gallbladder disease: the influence of diet in lean and obese mice. J Gastrointest Surg 2006;10:193–201.
  3. Mathur A, Murine M, Lu D, Swartz-Basile DA, Saxena R, Zyromski NJ, Pitt HA: Nonalcoholic fatty pancreas disease. HPB 2007;9:312–318.
  4. Schaffer JE: Lipotoxitcity: when tissues overeat. Curr Opin Lipidol 2003;14:281–287.
  5. Greenberg AS, Obin MS: Obesity and the role of adipose tissue in inflammation and metabolism. Am J Clin Nutr 2006;83:461S–465S.
  6. Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL, Ferrante AW Jr: Obesity is associated with macrophage accumulation in adipose tissue. J Clin Invest 2003;112:1796–1808.
  7. McCullough AJ: Pathophysiology of nonalcoholic steatohepatitis. J Clin Gastroenterol 2006;40:S17–S29.
  8. DeWaele B, Vanmierlo B, Van Nieuwenhove Y, Delvaux G: Impact of body overweight and class I, II and III obesity on the outcome of acute biliary pancreatitis. Pancreas 2006;32:343–345.
  9. Martinez J, Johnson CD, Sanchez-Paya J, de Madaria E, Robles-Diaz G, Perez-Mateo M: Obesity is a definitive risk factor of severity and mortality in acute pancreatitis: an updated meta-analysis. Pancreatology 2006;6:206–209.
  10. Papachristou GI, Papachristou DJ, Avula H, Slivka A, Whitcomb DC: Obesity increases the severity of acute pancreatitis: performance of APACHE-O score and correlation with the inflammatory response. Pancreatology 2006;6:279–285.
  11. Suazo-Barahona J, Carmona-Sanchez R, Robles-Diaz G, Milke-Garcia P, Vargas-Vorackova F, Uscanga-Dominguez L, Pelaez-Luna M: Obesity: a risk factor for severe acute biliary and alcoholic pancreatitis. Am J Gastroenterol 1998;93:1324–1328.
  12. Calle EE, Rodriguez C, Walker-Thurmond K, Thun MJ: Overweight, obesity, and mortality from cancer in a prospectively studied cohort of US adults. N Engl J Med 2003;348:1625–1638.
  13. Giovannucci E, Michaud D: The role of obesity and related metabolic disturbances in cancers of the colon, prostate, and pancreas. Gastroenterology 2007;132:2208–2225.
  14. Michaud DS, Giovannucci E, Willet WC, Colditz GA, Stampfer MJ, Fuchs CS: Physical activity, obesity, height and the risk of pancreatic cancer. JAMA 2001;286:921–929.
  15. Patel AV, Rodriguez C, Bernstein L, Chao A, Thun MJ, Calle EE: Obesity, recreational physical activity, and the risk of pancreatic cancer in a large US cohort. Cancer Epidemiol Biomarkers Prev 2005;14:459–466.
  16. Zyromski NJ, Mathur A, Yancey K, Gripe JT, Walker JJ, Lu D, Swartz-Basile DA, Lillemoe KD, Pitt HA: A murine model of obesity implicates the adipokine milieu in the pathogenesis of severe acute pancreatitis. Am J Physiol Gastrointest Liver Physiol 2008;295:G552–G558.
  17. Griffin JL, Nicholls AW: Metabolomics as a functional genomic tool for understanding lipid dysfunction in diabetes, obesity and related disorders. Pharmacogenomics 2006;7:1095–1107.
  18. Lindon JC, Holmes E, Nicholson JK: Metabolomics techniques and applications to pharmaceutical research and development. Pharm Res 1006;23:1075–1088.
  19. Kumada M, Kihara S, Ouchi N, Kobayashi H, Okamoto Y, Ohashi K, Maeda K, Nagaretani H, Kishida K, Maeda N, Nagasawa A, Funahashi T, Matsuzawa Y: Adiponectin specifically increased tissue inhibitor of metalloproteinase-1 through interleukin-10 expression in human macrophages. Circulation 2004;109:2046–2049.
  20. Lee JE, Choi SY, Huh W, Kim YG, Kim DJ, Oh HY: Metabolic syndrome, C-reactive protein, and chronic kidney disease in nondiabetic, nonhypertensive adults. Am J Hypertens 2007;20:1189–1194.
  21. Ogilvie RF: The islands of Langerhans in 19 cases of obesity. J Pathol Bacteriol 1933;37:473–481.

    External Resources

  22. Olsen TS: Lipomatosis of the pancreas in autopsy material and its relation to age and overweight. Acta Microbiol Scand Sect A 1978;86:367–373.
  23. Kovanlikaya A, Mittelman SD, Ward A, Geffner ME, Dorey F, Gilsanz V: Obesity and fat quantification in lean tissues using three-point Dixon MR imaging. Pediatr Radiol 2005;35:601–607.
  24. Matsumoto S, Mori H, Miyake H, Takaki H, Maeda T, Yamada Y, Oga M: Uneven fatty replacement of the pancreas: evaluation with CT. Radiology 1995;194:453–458.
  25. Mathur A, Pitt HA, Maxine M, Saxena R, Schmidt CM, Howard TJ, Nakeeb A, Zyromski NJ, Lillemoe KD: Fatty pancreas: a factor in postoperative pancreatic fistula. Ann Surg 2007;246:1058–1064.
  26. Hotamisligil GS, Shargill NS, Spiegelman BM: Adipose expression of tumor necrosis factor-alpha: direct role in obesity-linked insulin resistance. Science 1993;25p:87–91.

    External Resources

  27. Hirata T, Unoki H, Bujo H, Ueno K, Saito Y: Activation of diacylglycerol O-acyltransferase 1 gene results in increased tumor necrosis factor-alpha gene expression in 3T3-L1 adipocytes. FEBS Lett 2006;580:5117–5121.
  28. Cha MC, Chou CJ, Boozer CN: High-fat diet feeding reduces the diurnal variation of plasma leptin concentration in rats. Metabolism 2000;49:503–507.
  29. Fernandez-Real JM, Broch M, Vendrell J, Ricard W: Insulin resistance, inflammation, and serum fatty acid composition. Diabetes Care 2003;26:1362–1368.
  30. Lovejoy JC, Windhauser MM, Rood JC, de la Bretonne JA: Effect of a controlled high-fat versus low-fat diet on insulin sensitivity and leptin levels in African-American and Caucasian women. Metabolism 1998;47:1520–1524.
  31. Nguyen MT, Satoh H, Favelyukis S, Babendure JL, Imamura T, Sbodio JI, Zalevsky J, Dahiyat BI, Chi NW, Olefsky JM: JNK and tumor necrosis factor-alpha mediate free fatty acid-induced insulin resistance in 3T3-L2 adipocytes. J Biol Chem 2005;280:35361–35371.
  32. Bastard JP, Maachi M, Lagathu C, Kim MJ, Caron M, Vidal H, Capeau J, Feve B: Recent advances in the relationship between obesity, inflammation, and insulin resistance. Eur Cytokine Netw 2006;17:4–12.
  33. Boden G, She P, Mozzoli M, Cheung P, Gumireddy K, Reddy P, Xiang X, Luo Z, Ruderan N: Free fatty acids produce insulin resistance and activate the proinflammatory nuclear factor-kappaB pathway in rat liver. Diabetes 2005;54:3458–3465.
  34. Ghanim H, Aljada A, Hofmeyer D, Syed T, Mohanty P, Dandona P: Circulating mononuclear cells in the obese are in a proinflammatory state. Circulation 2004;110:1564–1571.
  35. Suganami T, Nishida J, Ogawa Y: A paracrine loop between adipocytes and macrophages aggravates inflammatory changes: role of free fatty acids and tumor necrosis factor alpha. Arterioscler Thromb Vasc Biol 2005;25:2062–2068.
  36. Inoguchi T, Li P, Umeda F, Yu HY, Kakimoto M, Imamura M, Aoki T, Etoh T, Hashimoto T, Naruse M, Sano H, Utsumi H, Nawata H: High glucose level and free fatty acids stimulate reactive oxygen species production through protein kinase C-dependent activation of NAD(P)H oxidase in cultured vascular cells. Diabetes 2000;49:1939–1945.
  37. Yannakoulia M, Yiannakouris N, Bluher S, Matalas AL, Klimis-Zacas D, Mantzoros CS: Body fat mass and macronutrient intake in relation to circulating soluble leptin receptor, free leptin index, adiponectin, and resistin concentrations in healthy humans. J Clin Endocrinol Metab 2003;88:1730–1736.
  38. Beger RD, Schnackenberg LK, Holland RD, Li D, Dragan Y: Metabolomic models of human pancreatic cancer using 1D proton NMR spectra of lipids in plasma. Metabolomics 2006;2:125–134.
  39. Fang F, He X, Deng H, Chen Q, Lu J, Spraul M, Yu Y: Discrimination of metabolic profiles of pancreatic cancer from chronic pancreatitis by high-resolution magic angle spinning 1H nuclear magnetic resonance and principal components analysis. Cancer Sci 2007;98:1678–1682.
  40. Shanaiah N, Desilva MA, Nagana Gowda GA, Raftery MA, Hainline BE, Raftery D: Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced 13C NMR. Proc Natl Acad Sci USA 2007;104:11540–11544.
  41. Chen HW, Pan Z, Talaty N, Cooks RG, Raftery D: Combining desorption electrospray ionization mass spectrometry and nuclear magnetic resonance for differential metabolomics without sample preparation. Rapid Commun Mass Spectrom 2006;20:1577–1584.
  42. Gu H, Chen H, Pan Z, Jackson AU, Talaty N, Xi B, Kissinger C, Duda C, Mann D, Raftery D, Cooks RG: Monitoring diet effects from biofluids and their implications for metabolomics studies. Anal Chem 2007;79:89–97.
  43. Pan Z, Raftery D: Combining NMR spectroscopy and mass spectrometry in metabolomics. Anal Bioanal Chem 2007;387:525–527.

  

Author Contacts

Nicholas J. Zyromski, MD
Department of Surgery, Indiana University School of Medicine
535 Barnhill Drive, RT 130
Indianapolis, IN 46202 (USA)
Tel. +1 317 274 5012, Fax +1 317 274 4554, E-Mail nzyromsk@iupui.edu

  

Article Information

N.J.Z. and A.M. contributed equally to the preparation of the manuscript. Presented at the American Pancreatic Association, Chicago, November 1–3, 2007.

Received: September 15, 2008
Accepted after revision: January 23, 2009
Published online: May 19, 2009
Number of Print Pages : 10
Number of Figures : 3, Number of Tables : 2, Number of References : 43

  

Publication Details

Pancreatology

Vol. 9, No. 4, Year 2009 (Cover Date: June 2009)

Journal Editor: Urrutia R. (Rochester, Minn.)
ISSN: 1424-3903 (Print), eISSN: 1424-3911 (Online)

For additional information: http://www.karger.com/PAN


Copyright / Drug Dosage / Disclaimer

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

Abstract

Background: Obesity is a worldwide epidemic and a significant risk factor for pancreatic diseases including pancreatitis and pancreatic cancer; the mechanisms underlying this association are unknown. Metabolomics is a powerful new analytical approach for describing the metabolome (compliment of small molecules) of cells, tissue or biofluids at any given time. Our aim was to analyze pancreatic fat content in lean and congenitally obese mice using both metabolomic analysis and conventional chromatography. Methods: The pancreatic fat content of 12 lean (C57BL/6J), 12 obese leptin-deficient (Lepob) and 12 obese hyperleptinemic (Lepdb) mice was evaluated by metabolomic analysis, thin-layer and gas chromatography. Results: Pancreata of congenitally obese mice had significantly more total pancreatic fat, triglycerides and free fatty acids, but significantly less phospholipids and cholesterol than those of lean mice. Metabolomic analysis showed excellent correlation with thin-layer and gas chromatography in measuring total fat, triglycerides and phospholipids. Conclusions: Differences in pancreatic fat content and character may have important implications when considering the local pancreatic proinflammatory milieu in obesity. Metabolomic analysis is a valid, powerful tool with which to further define the mechanisms by which fat impacts pancreatic disease.

© 2009 S. Karger AG, Basel and IAP


  

Author Contacts

Nicholas J. Zyromski, MD
Department of Surgery, Indiana University School of Medicine
535 Barnhill Drive, RT 130
Indianapolis, IN 46202 (USA)
Tel. +1 317 274 5012, Fax +1 317 274 4554, E-Mail nzyromsk@iupui.edu

  

Article Information

N.J.Z. and A.M. contributed equally to the preparation of the manuscript. Presented at the American Pancreatic Association, Chicago, November 1–3, 2007.

Received: September 15, 2008
Accepted after revision: January 23, 2009
Published online: May 19, 2009
Number of Print Pages : 10
Number of Figures : 3, Number of Tables : 2, Number of References : 43

  

Publication Details

Pancreatology

Vol. 9, No. 4, Year 2009 (Cover Date: June 2009)

Journal Editor: Urrutia R. (Rochester, Minn.)
ISSN: 1424-3903 (Print), eISSN: 1424-3911 (Online)

For additional information: http://www.karger.com/PAN


Article / Publication Details

First-Page Preview
Abstract of Original Paper

Received: 9/15/2008
Accepted: 1/23/2009
Published online: 5/19/2009
Issue release date: June 2009

Number of Print Pages: 10
Number of Figures: 3
Number of Tables: 2

ISSN: 1424-3903 (Print)
eISSN: 1424-3911 (Online)

For additional information: http://www.karger.com/PAN


Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

References

  1. Farrell GC, Larter CZ: Nonalcoholic fatty liver disease: from steatosis to cirrhosis. Hepatology 2006;43:S99–S112.
  2. Goldblatt MI, Swartz-Basile DA, Al-Azzawi HH, Tran KQ, Nakeeb A, Pitt HA: Nonalcoholic fatty gallbladder disease: the influence of diet in lean and obese mice. J Gastrointest Surg 2006;10:193–201.
  3. Mathur A, Murine M, Lu D, Swartz-Basile DA, Saxena R, Zyromski NJ, Pitt HA: Nonalcoholic fatty pancreas disease. HPB 2007;9:312–318.
  4. Schaffer JE: Lipotoxitcity: when tissues overeat. Curr Opin Lipidol 2003;14:281–287.
  5. Greenberg AS, Obin MS: Obesity and the role of adipose tissue in inflammation and metabolism. Am J Clin Nutr 2006;83:461S–465S.
  6. Weisberg SP, McCann D, Desai M, Rosenbaum M, Leibel RL, Ferrante AW Jr: Obesity is associated with macrophage accumulation in adipose tissue. J Clin Invest 2003;112:1796–1808.
  7. McCullough AJ: Pathophysiology of nonalcoholic steatohepatitis. J Clin Gastroenterol 2006;40:S17–S29.
  8. DeWaele B, Vanmierlo B, Van Nieuwenhove Y, Delvaux G: Impact of body overweight and class I, II and III obesity on the outcome of acute biliary pancreatitis. Pancreas 2006;32:343–345.
  9. Martinez J, Johnson CD, Sanchez-Paya J, de Madaria E, Robles-Diaz G, Perez-Mateo M: Obesity is a definitive risk factor of severity and mortality in acute pancreatitis: an updated meta-analysis. Pancreatology 2006;6:206–209.
  10. Papachristou GI, Papachristou DJ, Avula H, Slivka A, Whitcomb DC: Obesity increases the severity of acute pancreatitis: performance of APACHE-O score and correlation with the inflammatory response. Pancreatology 2006;6:279–285.
  11. Suazo-Barahona J, Carmona-Sanchez R, Robles-Diaz G, Milke-Garcia P, Vargas-Vorackova F, Uscanga-Dominguez L, Pelaez-Luna M: Obesity: a risk factor for severe acute biliary and alcoholic pancreatitis. Am J Gastroenterol 1998;93:1324–1328.
  12. Calle EE, Rodriguez C, Walker-Thurmond K, Thun MJ: Overweight, obesity, and mortality from cancer in a prospectively studied cohort of US adults. N Engl J Med 2003;348:1625–1638.
  13. Giovannucci E, Michaud D: The role of obesity and related metabolic disturbances in cancers of the colon, prostate, and pancreas. Gastroenterology 2007;132:2208–2225.
  14. Michaud DS, Giovannucci E, Willet WC, Colditz GA, Stampfer MJ, Fuchs CS: Physical activity, obesity, height and the risk of pancreatic cancer. JAMA 2001;286:921–929.
  15. Patel AV, Rodriguez C, Bernstein L, Chao A, Thun MJ, Calle EE: Obesity, recreational physical activity, and the risk of pancreatic cancer in a large US cohort. Cancer Epidemiol Biomarkers Prev 2005;14:459–466.
  16. Zyromski NJ, Mathur A, Yancey K, Gripe JT, Walker JJ, Lu D, Swartz-Basile DA, Lillemoe KD, Pitt HA: A murine model of obesity implicates the adipokine milieu in the pathogenesis of severe acute pancreatitis. Am J Physiol Gastrointest Liver Physiol 2008;295:G552–G558.
  17. Griffin JL, Nicholls AW: Metabolomics as a functional genomic tool for understanding lipid dysfunction in diabetes, obesity and related disorders. Pharmacogenomics 2006;7:1095–1107.
  18. Lindon JC, Holmes E, Nicholson JK: Metabolomics techniques and applications to pharmaceutical research and development. Pharm Res 1006;23:1075–1088.
  19. Kumada M, Kihara S, Ouchi N, Kobayashi H, Okamoto Y, Ohashi K, Maeda K, Nagaretani H, Kishida K, Maeda N, Nagasawa A, Funahashi T, Matsuzawa Y: Adiponectin specifically increased tissue inhibitor of metalloproteinase-1 through interleukin-10 expression in human macrophages. Circulation 2004;109:2046–2049.
  20. Lee JE, Choi SY, Huh W, Kim YG, Kim DJ, Oh HY: Metabolic syndrome, C-reactive protein, and chronic kidney disease in nondiabetic, nonhypertensive adults. Am J Hypertens 2007;20:1189–1194.
  21. Ogilvie RF: The islands of Langerhans in 19 cases of obesity. J Pathol Bacteriol 1933;37:473–481.

    External Resources

  22. Olsen TS: Lipomatosis of the pancreas in autopsy material and its relation to age and overweight. Acta Microbiol Scand Sect A 1978;86:367–373.
  23. Kovanlikaya A, Mittelman SD, Ward A, Geffner ME, Dorey F, Gilsanz V: Obesity and fat quantification in lean tissues using three-point Dixon MR imaging. Pediatr Radiol 2005;35:601–607.
  24. Matsumoto S, Mori H, Miyake H, Takaki H, Maeda T, Yamada Y, Oga M: Uneven fatty replacement of the pancreas: evaluation with CT. Radiology 1995;194:453–458.
  25. Mathur A, Pitt HA, Maxine M, Saxena R, Schmidt CM, Howard TJ, Nakeeb A, Zyromski NJ, Lillemoe KD: Fatty pancreas: a factor in postoperative pancreatic fistula. Ann Surg 2007;246:1058–1064.
  26. Hotamisligil GS, Shargill NS, Spiegelman BM: Adipose expression of tumor necrosis factor-alpha: direct role in obesity-linked insulin resistance. Science 1993;25p:87–91.

    External Resources

  27. Hirata T, Unoki H, Bujo H, Ueno K, Saito Y: Activation of diacylglycerol O-acyltransferase 1 gene results in increased tumor necrosis factor-alpha gene expression in 3T3-L1 adipocytes. FEBS Lett 2006;580:5117–5121.
  28. Cha MC, Chou CJ, Boozer CN: High-fat diet feeding reduces the diurnal variation of plasma leptin concentration in rats. Metabolism 2000;49:503–507.
  29. Fernandez-Real JM, Broch M, Vendrell J, Ricard W: Insulin resistance, inflammation, and serum fatty acid composition. Diabetes Care 2003;26:1362–1368.
  30. Lovejoy JC, Windhauser MM, Rood JC, de la Bretonne JA: Effect of a controlled high-fat versus low-fat diet on insulin sensitivity and leptin levels in African-American and Caucasian women. Metabolism 1998;47:1520–1524.
  31. Nguyen MT, Satoh H, Favelyukis S, Babendure JL, Imamura T, Sbodio JI, Zalevsky J, Dahiyat BI, Chi NW, Olefsky JM: JNK and tumor necrosis factor-alpha mediate free fatty acid-induced insulin resistance in 3T3-L2 adipocytes. J Biol Chem 2005;280:35361–35371.
  32. Bastard JP, Maachi M, Lagathu C, Kim MJ, Caron M, Vidal H, Capeau J, Feve B: Recent advances in the relationship between obesity, inflammation, and insulin resistance. Eur Cytokine Netw 2006;17:4–12.
  33. Boden G, She P, Mozzoli M, Cheung P, Gumireddy K, Reddy P, Xiang X, Luo Z, Ruderan N: Free fatty acids produce insulin resistance and activate the proinflammatory nuclear factor-kappaB pathway in rat liver. Diabetes 2005;54:3458–3465.
  34. Ghanim H, Aljada A, Hofmeyer D, Syed T, Mohanty P, Dandona P: Circulating mononuclear cells in the obese are in a proinflammatory state. Circulation 2004;110:1564–1571.
  35. Suganami T, Nishida J, Ogawa Y: A paracrine loop between adipocytes and macrophages aggravates inflammatory changes: role of free fatty acids and tumor necrosis factor alpha. Arterioscler Thromb Vasc Biol 2005;25:2062–2068.
  36. Inoguchi T, Li P, Umeda F, Yu HY, Kakimoto M, Imamura M, Aoki T, Etoh T, Hashimoto T, Naruse M, Sano H, Utsumi H, Nawata H: High glucose level and free fatty acids stimulate reactive oxygen species production through protein kinase C-dependent activation of NAD(P)H oxidase in cultured vascular cells. Diabetes 2000;49:1939–1945.
  37. Yannakoulia M, Yiannakouris N, Bluher S, Matalas AL, Klimis-Zacas D, Mantzoros CS: Body fat mass and macronutrient intake in relation to circulating soluble leptin receptor, free leptin index, adiponectin, and resistin concentrations in healthy humans. J Clin Endocrinol Metab 2003;88:1730–1736.
  38. Beger RD, Schnackenberg LK, Holland RD, Li D, Dragan Y: Metabolomic models of human pancreatic cancer using 1D proton NMR spectra of lipids in plasma. Metabolomics 2006;2:125–134.
  39. Fang F, He X, Deng H, Chen Q, Lu J, Spraul M, Yu Y: Discrimination of metabolic profiles of pancreatic cancer from chronic pancreatitis by high-resolution magic angle spinning 1H nuclear magnetic resonance and principal components analysis. Cancer Sci 2007;98:1678–1682.
  40. Shanaiah N, Desilva MA, Nagana Gowda GA, Raftery MA, Hainline BE, Raftery D: Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced 13C NMR. Proc Natl Acad Sci USA 2007;104:11540–11544.
  41. Chen HW, Pan Z, Talaty N, Cooks RG, Raftery D: Combining desorption electrospray ionization mass spectrometry and nuclear magnetic resonance for differential metabolomics without sample preparation. Rapid Commun Mass Spectrom 2006;20:1577–1584.
  42. Gu H, Chen H, Pan Z, Jackson AU, Talaty N, Xi B, Kissinger C, Duda C, Mann D, Raftery D, Cooks RG: Monitoring diet effects from biofluids and their implications for metabolomics studies. Anal Chem 2007;79:89–97.
  43. Pan Z, Raftery D: Combining NMR spectroscopy and mass spectrometry in metabolomics. Anal Bioanal Chem 2007;387:525–527.