Increased calcium uptake and improved trabecular bone properties in intestinal alkaline phosphatase knockout mice

BRUN LR; LOMBARTE M; ROMA SM; PEREZ F; MILLÁN JL; RIGALLI A

JOURNAL OF BONE AND MINERAL METABOLISM.

SPRINGER TOKYO

Lugar: Tokyo; Año: 2018 vol. 36 p. 661 - 667

0914-8779

Previousstudies have demonstrated a negative correlation between intestinal alkalinephosphatase (IAP) activity and calcium (Ca) absorption in the gut, as IAP actsas a protective mechanism inhibiting high Ca entry into enterocytes preventing Caoverload. Here we evaluated Ca absorption and bone properties in knockout mice(KO) completely devoid of duodenal IAP (Akp3-/-mice). Female C57BL/6 control mice (WT, n=7) and KO mice (n=10) were used todetermine Ca absorption in vivo andby in situ isolated duodenal loopsfollowed by histomorphometric analysis of duodenal villi and crypts. Bonemineral density, morphometry, histomorphometry and trabecular connectivity andbiomechanical properties were measured on bones. We observed mild atrophy ofthe villi with lower absorption surface and a significant higher Ca uptake inKO mice. While no changes were seen in cortical bone, we found bettertrabecular connectivity and biomechanical properties in the femurs of KO micecompared to WT mice. Our data indicate that IAP KO mice display higher intestinalCa uptake, which overtime appears to correlate with a positive effect on thebiomechanical properties of trabecular bone.