Abstract: FR-PO167
Vitamin K-Dependent Proteins After Kidney Transplantation: Results from a Prospective Study
Session Information
- Bone and Mineral Metabolism: Phosphorus, FGF23, Vascular Calcification
November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bone and Mineral Metabolism
- 402 Bone and Mineral Metabolism: Clinical
Authors
- Fusaro, Maria, National Research Council (CNR) e Institute of Clinical Physiology (IFC), Pisa, Italy
- Khairallah, Pascale, Columbia University Medical Center, New York, New York, United States
- Aghi, Andrea, Nephrology Unit, University of Padua, Padova, Italy
- Plebani, Mario, Laboratory Medicine Unit, Department of Medicine, University of Padova, Padova, Italy
- Zaninotto, Martina, University Hospital, Padova, Italy
- Cosma, Chiara, University Hospital, Padova, Italy
- Aponte Farias, Maria A., Columbia University Medical Center, New York, New York, United States
- Cortez, Natalia Erika, University of California, Davis, Davis, California, United States
- Tripepi, Giovanni, IFC-CNR, Calabria, Italy
- Nickolas, Tom, Columbia University Medical Center, New York, New York, United States
Background
Two Vitamin K-dependent proteins (VDKPs) link bone and vasculature in CKD-MBD: Bone Gla Protein (BGP) and Matrix Gla Protein (MGP). In ESKD, Vitamin K deficiency is highly prevalent and leads to increased levels of inactive VKDPs (undercaboxylated(uc) BGP and dephosphorylated(dp)-uc MGP), which are linked to greater risk of fractures and severity of vascular calcification. We hypothesized that kidney transplantation (KT) would improve Vitamin K status and lower levels of inactive VKDPs.
Methods
Between 2014-2017, we conducted a study in 34 patients to assess changes in VKDPs during the 1st year of KT. In a specialized lab we determined VKDPs pre- and 1-year post-KT: total BGP, uc BGP, total MGP, and dp-uc MGP. We determined the prevalence of Vitamin K deficiency based on levels of uc-BGP and dp-uc MGP
Results
Our cohort had a mean+/-SD age of 48+/-14 years, 32% were female and 97% were Caucasian. 1 year post-KT, there was a decrease in the levels of all VKDPs and the prevalence of Vitamin K deficiency(Table). Patients with greatest severity of Vitamin K deficiency pre-KT had the largest decreases of inactive VDKPs post-KT (Figure).
Conclusion
KT was associated with improvement in Vitamin K status as manifested by decreased levels of inactive VKDPs. These are the first prospective data on VKDPs in CKD patients pre- and post-KT. Studies are needed to assess the impact of improvement in VKDP status after KT on CKD-MBD outcomes.
VKDPs pre- and post-KT
| Variable | Pre-KT | Post-KT | P-Value |
| uc-BGP ng/mL (median; IQR) | 8.56 (5.45, 9.55) | 3.41 (1.24, 4.80) | < 0.001 |
| Vitamin K deficient by uc-BGP – n (%) (Cut-Off: uc-BGP>=4.5 ng/ml) * | 26 (76.5%) | 11 (32.4%) | <0.001 |
| BGP ng/mL (median; IQR) | 132 (79.85, 279.5) | 22.55 (18.85, 30.6) | <0.001 |
| MGP nmol/L (median; IQR) | 29.19 (26.67, 32.30) | 20.15 (14.68, 23.23) | <0.001 |
| dp-ucMGP pmol/L (median; IQR) | 910.5 (653.3, 1396.5) | 637 (517, 777.5) | < 0.001 |
| Vitamin K deficient by dp-ucMGP- n (%) (Cut-Off: dp-uc MGP>500 pmol/L) | 33 (97.1%) | 27 (79.4%) | 0.012 |
*(Kuwabara et al. Osteoporos Int 2009)
Changes in circulating dp-ucMGP levels in relation to baseline values
Funding
- Private Foundation Support