Vincent Castiglione1, Hans Pottel2, John Charles Lieske3, Pierre Lukas4, Etienne Cavalier4, Pierre Delanaye5, Andrew David Rule3. 1. Department of Clinical Chemistry, CHU of Liège, University of Liège (ULg CHU), Liège, Belgium. V.Castiglione@doct.uliege.be. 2. Department of Public Health and Primary Care, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium. 3. Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA. 4. Department of Clinical Chemistry, CHU of Liège, University of Liège (ULg CHU), Liège, Belgium. 5. Department of Nephrology, Dialysis and Transplantation, CHU of Liège, University of Liège (ULg CHU), Liège, Belgium.
Abstract
BACKGROUND: Matrix-Gla-protein (MGP) is an inhibitor of vascular calcification. Its dephosphorylated and uncarboxylated inactive form, dpucMGP, is a marker of vitamin K status and of cardio-vascular outcomes in chronic kidney disease. We hypothesized that higher serum dpucMGP would be a biomarker of kidney stone disease. METHODS: We measured serum dpucMGP in incident symptomatic kidney stone-formers and non-stone formers at a baseline visit. Symptomatic stone recurrence was assessed in the stones formers over a 5-year period. The association of dpucMGP with incident or recurrent kidney stones was assessed with and without adjustment for clinical, blood, and urine characteristics. RESULTS: There was no significant difference in serum dpucMGP level between 498 stone formers and 395 non-stone former (510 vs 501 pmol/L; p = 0.66). In a multivariable model adjusting for clinical, blood and urine chemistries, higher MGP was associated with lower risk of stone formation (OR = 0.674, 95% CI 0.522-0.870), contrary to previous reports. Among 375 stone formers with 5 years of follow-up, 79 (21%) had symptomatic recurrence. No difference in serum dpucMGP was evident in recurrent versus non-recurrent stone-formers (482 vs 502 pmol/L; p = 0.26). Serum dpucMGP was correlated with cystatin C levels in non stone-formers, incident stone-formers and recurrent stone-formers (r > 0.3, p < 0.0001). CONCLUSION: Elevated serum dpucMGP was not associated with incident or recurrent symptomatic kidney stone events. However, higher level of dpucMGP was associated with lower risk of kidney stone in a multivariable logistic regression model.
BACKGROUND:Matrix-Gla-protein (MGP) is an inhibitor of vascular calcification. Its dephosphorylated and uncarboxylated inactive form, dpucMGP, is a marker of vitamin K status and of cardio-vascular outcomes in chronic kidney disease. We hypothesized that higher serum dpucMGP would be a biomarker of kidney stone disease. METHODS: We measured serum dpucMGP in incident symptomatic kidney stone-formers and non-stone formers at a baseline visit. Symptomatic stone recurrence was assessed in the stones formers over a 5-year period. The association of dpucMGP with incident or recurrent kidney stones was assessed with and without adjustment for clinical, blood, and urine characteristics. RESULTS: There was no significant difference in serum dpucMGP level between 498 stone formers and 395 non-stone former (510 vs 501 pmol/L; p = 0.66). In a multivariable model adjusting for clinical, blood and urine chemistries, higher MGP was associated with lower risk of stone formation (OR = 0.674, 95% CI 0.522-0.870), contrary to previous reports. Among 375 stone formers with 5 years of follow-up, 79 (21%) had symptomatic recurrence. No difference in serum dpucMGP was evident in recurrent versus non-recurrent stone-formers (482 vs 502 pmol/L; p = 0.26). Serum dpucMGP was correlated with cystatin C levels in non stone-formers, incident stone-formers and recurrent stone-formers (r > 0.3, p < 0.0001). CONCLUSION: Elevated serum dpucMGP was not associated with incident or recurrent symptomatic kidney stone events. However, higher level of dpucMGP was associated with lower risk of kidney stone in a multivariable logistic regression model.