title: Elevated fasting and postprandial C-terminal telopeptide after Roux-en-Y gastric bypass.
abstract: Background Roux-en-Y gastric bypass increases circulating bile acid concentrations, known mediators of postprandial suppression of markers of bone resorption. Long-term data, however, indicate that Roux-en-Y gastric bypass confers an increased risk of bone loss on recipients. Methods Thirty-six obese individuals, median age 44 (26-64) with median body mass index at baseline of 42.5 (40.4-46) were studied before and 15 months after Roux-en-Y gastric bypass. After an overnight fast, patients received a 400 kcal mixed meal. Blood samples were collected premeal then at 30-min periods for 120 min. Pre and postmeal samples were analysed for total bile acids, parathyroid hormone and C-terminal telopeptide. Results Body weight loss post Roux-en-Y gastric bypass was associated with a median 4.9-fold increase in peak postprandial total bile acid concentration, and a median 2.4-fold increase in cumulative food evoked bile acid response. Median fasting parathyroid hormone, postprandial reduction in parathyroid hormone and total parathyroid hormone release over 120 min remained unchanged after surgery. After surgery, median fasting C-terminal telopeptide increased 2.3-fold, peak postprandial concentrations increased 3.8-fold and total release was increased 1.9-fold. Conclusions Fasting and postprandial total bile acids and C-terminal telopeptide are increased above reference range after Roux-en-Y gastric bypass. These changes occur in spite of improved vitamin D status with supplementation. These results suggest that post-Roux-en-Y gastric bypass increases in total bile acids do not effectively oppose an ongoing resorptive signal operative along the gut-bone axis. Serial measurement of C-terminal telopeptide may be of value as a risk marker for long-term skeletal pathology in patients post Roux-en-Y gastric bypass.
authors.affiliation: 1 Department of Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, UK.|2 Department of Chemical Pathology, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Negar
authors.initials: N
authors.lastname: Maghsoodi
authors.affiliation: 2 Department of Chemical Pathology, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Jamshid
authors.initials: J
authors.lastname: Alaghband-Zadeh
authors.affiliation: 1 Department of Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, UK.
authors.forename: Gemma F
authors.initials: GF
authors.lastname: Cross
authors.affiliation: 3 Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|4 Department of Surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.
authors.forename: Malin
authors.initials: M
authors.lastname: Werling
authors.affiliation: 3 Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|4 Department of Surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Fändriks
authors.affiliation: 3 Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|4 Department of Surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.|5 Diabetes Complications Research Centre, Conway Institute, University College Dublin, Ireland.
authors.forename: Neil G
authors.initials: NG
authors.lastname: Docherty
authors.affiliation: 3 Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|4 Department of Surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.
authors.forename: Torsten
authors.initials: T
authors.lastname: Olbers
authors.affiliation: 1 Department of Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, UK.
authors.forename: Tracy
authors.initials: T
authors.lastname: Dew
authors.affiliation: 1 Department of Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, UK.
authors.forename: Roy A
authors.initials: RA
authors.lastname: Sherwood
authors.affiliation: 1 Department of Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, UK.
authors.forename: Royce P
authors.initials: RP
authors.lastname: Vincent
authors.affiliation: 3 Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|4 Department of Surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.|5 Diabetes Complications Research Centre, Conway Institute, University College Dublin, Ireland.
authors.forename: Carel W
authors.initials: CW
authors.lastname: le Roux
mesh_terms: D000328:Adult; D001647:Bile Acids and Salts / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D001862:Bone Resorption / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D024042:Collagen Type I / Q000097:blood*; D005215:Fasting; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000473:pathology / Q000601:surgery; D010455:Peptides / Q000097:blood*; D019518:Postprandial Period; D011446:Prospective Studies; D012306:Risk; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood
chemical_list: D001647:Bile Acids and Salts; D015415:Biomarkers; D001786:Blood Glucose; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D014807:Vitamin D
keywords: C-terminal telopeptide; Roux-en-Y gastric bypass; bile acids; parathyroid hormone