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Abstract: SA-PO161

Vascular Calcification Is Associated With Fetuin-A and Cortical Bone Porosity in Stone Formers

Session Information

Category: Bone and Mineral Metabolism

  • 402 Bone and Mineral Metabolism: Clinical

Authors

  • Rodrigues, Fernanda Guedes, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Neves, Rodrigo Azambuja, Universidade Federal de Sao Paulo Hospital do Rim e Hipertensao, Sao Paulo, São Paulo, Brazil
  • Ormanji, Milene Subtil, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Esper, Priscila Ligeiro Goncalves, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • Requiao-moura, Lucio Roberto, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
  • De Borst, Martin H., Rijksuniversiteit Groningen, Groningen, Groningen, Netherlands
  • Heilberg, Ita Pfeferman, Universidade Federal de Sao Paulo, Sao Paulo, São Paulo, Brazil
Background

Nephrolithiasis has been associated with bone loss and cardiovascular disease as well as vascular calcification (VC), reflecting abnormal extraosseous calcium deposition. Fetuin-A (Fet-A) acts as a potent inhibitor of ectopic mineralization. The aim of the present study was to evaluate the prevalence of VC in stone formers (SF) compared to non-stone formers (NSF) and to investigate the relationship of Fet-A and bone microarchitecture with VC among SF.

Methods

Post-hoc analysis of a cross-sectional trial that evaluated bone microarchitecture parameters by high-resolution peripheral quantitative computed tomography (HR-pQCT) in young SF. Abdominal aortic calcification (AAC) was assessed as a marker of VC, using computed tomography in SF and in age-, sex- and BMI-matched NSF (potential living kidney donors). The association of AAC with serum Fet-A, measured in SF stored blood samples, and with HR-pQCT parameters and other factors was studied using multivariable logistic regression analysis.

Results

A total of 62 SF (age 38.0 [28.0-45.3] years) and 80 NSF (40.0 [37.0-45.8] years) were included. There was no statistically significant difference in AAC scores between SF (5.8 ± 0.8 %) and NSF (5.6 ± 0.7 %, p = 0.27). When dividing SF according to their mean value of AAC score, below <5.8% (n=33) or above ≥ 5.8% (n=29), SF with higher AAC had significantly higher BMI and tibial cortical porosity (Ct.Po) and significantly lower serum HDL, klotho, Fet-A and eGFR. Urinary calcium did not differ between groups but fractional excretion of phosphate was higher in SF with higher AAC. Upon multivariate regression analysis, BMI (β 0.31, p<0.01), serum Fet-A (β -0.29, p=0.02) and tibial Ct.Po (β 0.26, p=0.03) were independently associated with AAC (Table 1).

Conclusion

This study demonstrates associations of reduced circulating Fet-A levels and higher tibial porosity with AAC, supporting Fet-A as central mediator in the kidney-bone-vasculature axis.