title: Assessment of plasma acylcarnitines before and after weight loss in obese subjects.
abstract: Acylcarnitines, fatty acid oxidation (FAO) intermediates, have been implicated in diet-induced insulin resistance and type 2 diabetes mellitus, as increased levels are found in obese insulin resistant humans. Moreover plasma acylcarnitines have been associated with clinical parameters related to glucose metabolism, such as fasting glucose levels and HbA1c. We hypothesized that plasma acylcarnitines would correlate with energy expenditure, insulin sensitivity and other clinical parameters before and during a weight loss intervention. We measured plasma acylcarnitines in 60 obese subjects before and after a 12 week weight loss intervention. These samples originated from three different interventions (diet alone (n = 20); diet and exercise (n = 21); diet and drug treatment (n = 19)). Acylcarnitine profiles were analysed in relation to clinical parameters of glucose metabolism, insulin sensitivity and energy expenditure. Conclusions were drawn from all 60 subjects together. Despite amelioration of HOMA-IR, plasma acylcarnitines levels increased during weight loss. HOMA-IR, energy expenditure and respiratory exchange ratio were not related to plasma acylcarnitines. However non-esterified fatty acids correlated strongly with several acylcarnitines at baseline and during the weight loss intervention (p < 0.001). Acylcarnitines did not correlate with clinical parameters of glucose metabolism during weight loss, questioning their role in insulin resistance and type 2 diabetes mellitus.
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, The Netherlands. Electronic address: m.g.schooneman@amc.uva.nl.
authors.forename: Marieke G
authors.initials: MG
authors.lastname: Schooneman
authors.affiliation: GlaxoSmithKline Research and Development, Research Triangle Park, NC, 27709, USA.
authors.forename: Antonella
authors.initials: A
authors.lastname: Napolitano
authors.affiliation: Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, NY, USA.
authors.forename: Sander M
authors.initials: SM
authors.lastname: Houten
authors.affiliation: Institute of Metabolic Science, Metabolic Research Laboratories, Cambridge University Hospital NHS Trust, Cambridge, UK.
authors.forename: Graeme K
authors.initials: GK
authors.lastname: Ambler
authors.affiliation: NIHR Wellcome Trust Clinical Research Facility, Cambridge University Hospital NHS Trust, Cambridge, UK.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Murgatroyd
authors.affiliation: GlaxoSmithKline Research and Development, Research Triangle Park, NC, 27709, USA.
authors.forename: Sam R
authors.initials: SR
authors.lastname: Miller
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Carla E M
authors.initials: CE
authors.lastname: Hollak
authors.affiliation: Institute of Metabolic Science, Metabolic Research Laboratories, Cambridge University Hospital NHS Trust, Cambridge, UK.
authors.forename: Chong Y
authors.initials: CY
authors.lastname: Tan
authors.affiliation: Institute of Metabolic Science, Metabolic Research Laboratories, Cambridge University Hospital NHS Trust, Cambridge, UK.
authors.forename: Samuel
authors.initials: S
authors.lastname: Virtue
authors.affiliation: Institute of Metabolic Science, Metabolic Research Laboratories, Cambridge University Hospital NHS Trust, Cambridge, UK.
authors.forename: Antonio
authors.initials: A
authors.lastname: Vidal-Puig
authors.affiliation: GlaxoSmithKline Research and Development, Research Triangle Park, NC, 27709, USA.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Nunez
authors.affiliation: Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Institute of Metabolic Science, Metabolic Research Laboratories, Cambridge University Hospital NHS Trust, Cambridge, UK. Electronic address: http://www.metabolism.maartensoeters.nl/
authors.forename: Maarten R
authors.initials: MR
authors.lastname: Soeters
mesh_terms: D000328:Adult; D000886:Anthropometry; D001823:Body Composition; D002331:Carnitine / Q000031:analogs & derivatives* / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005227:Fatty Acids / Q000737:chemistry; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005947:Glucose / Q000737:chemistry; D006801:Humans; D007333:Insulin Resistance; D008066:Lipolysis; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications; D010100:Oxygen / Q000737:chemistry; D012119:Respiration; D015431:Weight Loss; D055815:Young Adult
chemical_list: D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; C116917:acylcarnitine; D005947:Glucose; D002331:Carnitine; D010100:Oxygen
keywords: Acylcarnitines; Fatty acid oxidation; Insulin resistance; Weight loss