Valerie Hage1, Solenne Pelletier2, Laurence Dubourg3, Jocelyne Drai4, Charlotte Cuerq5, Sandrine Lemoine6, Aoumeur Hadj-Aissa3, Maurice Laville7, Denis Fouque8. 1. Département de Néphrologie-Dialyse-Nutrition, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Pierre Bénite, France. 2. Département de Néphrologie-Dialyse-Nutrition, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Pierre Bénite, France; Service d'Explorations Fonctionnelles Rénales et Métaboliques, Hôpital Edouard Herriot, Lyon, France; INSERM U1033, Hôpital Edouard HERRIOT, Lyon, France. 3. Service d'Explorations Fonctionnelles Rénales et Métaboliques, Hôpital Edouard Herriot, Lyon, France. 4. Laboratoire de Biochimie, Centre Hospitalier Lyon-Sud, Pierre Bénite, France; INSERM 1060 CARMEN CENS Université de Lyon, F-69622 Lyon, France. 5. Laboratoire de Biochimie, Centre Hospitalier Lyon-Sud, Pierre Bénite, France. 6. Service d'Explorations Fonctionnelles Rénales et Métaboliques, Hôpital Edouard Herriot, Lyon, France; INSERM 1060 CARMEN CENS Université de Lyon, F-69622 Lyon, France. 7. Département de Néphrologie-Dialyse-Nutrition, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Pierre Bénite, France; INSERM 1060 CARMEN CENS Université de Lyon, F-69622 Lyon, France. 8. Département de Néphrologie-Dialyse-Nutrition, Centre Hospitalier Lyon-Sud, Hospices Civils de Lyon, Pierre Bénite, France; INSERM 1060 CARMEN CENS Université de Lyon, F-69622 Lyon, France. Electronic address: denis.fouque@chu-lyon.fr.
Abstract
OBJECTIVES: Klotho is an "aging-suppressor" gene and encodes a single-pass transmembrane protein predominantly expressed in renal tubules. Whether chronic kidney disease (CKD) affects serum Klotho is poorly documented. We aimed to measure the relationship of serum α-Klotho with renal function, acid-base status, bone biomarkers, and proteinuria in CKD patients. DESIGN SETTING, PARTICIPANTS, AND MEASUREMENTS: We measured serum α-Klotho, serum FGF23, and glomerular filtration rate by inulin clearance in 60 CKD patients between January and July 2011. We also measured serum creatinine, bicarbonate, calcium, phosphorus, parathyroid hormone, C-reactive protein, and 25-OH vitamin D. Proteinuria was obtained from a 24-h urine collection. RESULTS: The median serum α-Klotho was 478 (348-658) pg/mL. We found an inverse relationship between serum α-Klotho and serum creatinine (r = -0.36, P = .007), proteinuria (r = -0.36, P = .013), and a positive relationship with serum bicarbonate (r = 0.33, P = .011). There was no further significant relation between serum α-Klotho and inulin clearance or serum FGF23. Multiple regression analysis including serum bicarbonate, serum creatinine, and proteinuria indicated that only serum bicarbonate was associated with serum α-Klotho (P = .003). CONCLUSIONS: This study shows that in CKD, serum α-Klotho is related to serum bicarbonate and proteinuria and not to renal function. Further research is required to determine whether correcting these 2 amenable conditions would improve serum α-Klotho.
OBJECTIVES:Klotho is an "aging-suppressor" gene and encodes a single-pass transmembrane protein predominantly expressed in renal tubules. Whether chronic kidney disease (CKD) affects serum Klotho is poorly documented. We aimed to measure the relationship of serum α-Klotho with renal function, acid-base status, bone biomarkers, and proteinuria in CKDpatients. DESIGN SETTING, PARTICIPANTS, AND MEASUREMENTS: We measured serum α-Klotho, serum FGF23, and glomerular filtration rate by inulin clearance in 60 CKDpatients between January and July 2011. We also measured serum creatinine, bicarbonate, calcium, phosphorus, parathyroid hormone, C-reactive protein, and 25-OH vitamin D. Proteinuria was obtained from a 24-h urine collection. RESULTS: The median serum α-Klotho was 478 (348-658) pg/mL. We found an inverse relationship between serum α-Klotho and serum creatinine (r = -0.36, P = .007), proteinuria (r = -0.36, P = .013), and a positive relationship with serum bicarbonate (r = 0.33, P = .011). There was no further significant relation between serum α-Klotho and inulin clearance or serum FGF23. Multiple regression analysis including serum bicarbonate, serum creatinine, and proteinuria indicated that only serum bicarbonate was associated with serum α-Klotho (P = .003). CONCLUSIONS: This study shows that in CKD, serum α-Klotho is related to serum bicarbonate and proteinuria and not to renal function. Further research is required to determine whether correcting these 2 amenable conditions would improve serum α-Klotho.
Authors: Rukshana Shroff; Helen Aitkenhead; Nikola Costa; Antonella Trivelli; Mieczyslaw Litwin; Stefano Picca; Ali Anarat; Peter Sallay; Fatih Ozaltin; Aleksandra Zurowska; Augustina Jankauskiene; Giovanni Montini; Marina Charbit; Franz Schaefer; Elke Wühl Journal: J Am Soc Nephrol Date: 2015-06-11 Impact factor: 10.121