title: Fibroblast Growth Factor-23, Sclerostin, and Bone Microarchitecture in Patients With Osteoporotic Fractures of the Proximal Femur: A Cross-sectional Study.
abstract: This cross-sectional observational cohort study was designed to simultaneously investigate bone microarchitecture and serum markers of bone metabolism in elderly osteoporotic patients experiencing a trochanteric or femoral neck fracture. Special emphasis was put on renal function, sclerostin and fibroblast growth factor-23 (FGF-23). Eighty-two patients (median age: 84 years; 49 trochanteric fractures) scheduled for emergency surgery due to an osteoporotic fracture participated. Bone specimens for ex vivo microcomputed X-ray tomography were sampled during surgery. Blood samples for laboratory workup were collected before surgery (t0) and 1 day afterward (t1). Fifty-eight patients consented to dual-energy X-ray absorptiometry scanning of the lumbar spine and/or contralateral femoral neck after recovery during the in-patient stay. Samples were grouped according to the site of fracture. Regression coefficients were controlled for age and/or estimated glomerular filtration rate (eGFR), if appropriate. Patients experiencing a femoral neck fracture presented with better preserved renal function (eGFR) and lower C-terminal fragment of fibroblast growth factor-23 (cFGF-23) concentrations compared to those with trochanteric fractures. By contrast, serum sclerostin was similar at both time points and did not differ between groups. Age-adjusted correlation analysis revealed negative associations between eGFR and cFGF-23 determined at t1 (R=-0.34; p<0.05) as well as between eGFR and sclerostin levels at t0 (R=-0.45; p<0.05) in patients with trochanteric and femoral neck fractures, respectively. Our study provides evidence that not only an age-related decline of renal function but also the type of skeletal injury may contribute to the circulating concentrations of cFGF-23.
authors.affiliation: Department of Traumatology, Hand and Reconstructive Surgery, University of Rostock, Rostock, Germany.
authors.forename: Philipp K E
authors.initials: PK
authors.lastname: Herlyn
authors.affiliation: Department of Traumatology, Hand and Reconstructive Surgery, University of Rostock, Rostock, Germany.
authors.forename: Norina
authors.initials: N
authors.lastname: Cornelius
authors.affiliation: Department of Paediatrics, University of Rostock, Rostock, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Haffner
authors.affiliation: Department of Paediatrics, University of Rostock, Rostock, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Zaage
authors.affiliation: Department of Orthopaedics, University of Rostock, Rostock, Germany.
authors.forename: Cornelius
authors.initials: C
authors.lastname: Kasch
authors.affiliation: Department of Internal Medicine, Klinikum Südstadt Rostock, Rostock, Germany.
authors.forename: Hans-Christof
authors.initials: HC
authors.lastname: Schober
authors.affiliation: Department of Traumatology, Hand and Reconstructive Surgery, University of Rostock, Rostock, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mittlmeier
authors.affiliation: Department of Paediatrics, University of Rostock, Rostock, Germany. Electronic address: dagmar-christiane.fischer@med.uni-rostock.de.
authors.forename: Dagmar-C
authors.initials: DC
authors.lastname: Fischer
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D019485:Bone Morphogenetic Proteins / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005265:Femoral Neck Fractures / Q000378:metabolism / Q000473:pathology; D005272:Femur Neck / Q000000981:diagnostic imaging; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D005819:Genetic Markers; D005858:Germany; D005919:Glomerular Filtration Rate; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D058866:Osteoporotic Fractures / Q000378:metabolism / Q000473:pathology; D012307:Risk Factors; D013223:Statistics as Topic
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; C000717427:FGF23 protein, human; D005819:Genetic Markers; C422903:SOST protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23
keywords: DXA; osteoporosis; proximal femur fracture; μCT