gastrins and Fractures--Bone

Proton pump inhibitors (PPIs) are widely used against gastroesophageal reflux disease. Recent epidemiological studies suggest that PPI users have an increased risk of fractures, but a causal relationship has been questioned. We have therefore investigated the skeletal phenotype in H(+) /K(+) ATPase beta-subunit knockout (KO) female mice. Skeletal parameters were determined in 6- and 20-month-old KO mice and in wild-type controls (WT). Whole body bone mineral density (BMD) and bone mineral content (BMC) were measured by dual energy X-ray absorptiometry (DXA). Femurs were examined with µCT analyses and break force were examined by a three-point bending test. Plasma levels of gastrin, RANKL, OPG, osteocalcin, leptin, and PTH were analyzed. KO mice had lower whole body BMC at 6 months (0.53 vs. 0.59 g, P = 0.035) and at 20 months (0.49 vs. 0.74 g, P < 0.01) compared to WT as well as lower BMD at 6 months (0.068 vs. 0.072 g/cm(2) , P = 0.026) and 20 months (0.067 vs. 0.077 g/cm(2) , P < 0.01). Mechanical strength was lower in KO mice at the age of 20 months (6.7 vs. 17.9 N, P < 0.01). Cortical thickness at 20 months and trabecular bone volume% at 6 months were significantly reduced in KO mice. Plasma OPG/RANKL ratio and PTH was increased in KO mice compared to controls. H(+) /K(+) ATPase beta subunit KO mice had decreased BMC and BMD, reduced cortical thickness and inferior mechanical bone strength. Whereas the mechanism is uncertain, these findings suggest a causal relationship between long-term PPI use and an increased risk of fractures.

Topics: Absorptiometry, Photon; Animals; Bone and Bones; Bone Density; Female; Fractures, Bone; Gastrins; Leptin; Mice; Mice, Inbred BALB C; Mice, Knockout; Mitochondrial Proton-Translocating ATPases; Osteocalcin; Osteoprotegerin; Parathyroid Hormone; Protein Subunits; Proton Pump Inhibitors; RANK Ligand; Risk

Proton pump inhibitors (PPI) remain the leading therapy for acid-related disorders. Long-term PPI use increases the risk of pneumonia and enteric bacterial infections and of nosocomial Clostridium difficile-associated diarrhoea. PPIs do not lead to vitamin B12 or iron deficiencies and do not induce malignancies or increase the risk of major birth defects. Prolonged PPI use may be a weak risk factor for certain fractures and results in hypergastrinaemia and parietal cell hyperplasia leading to rebound acid hypersecretion, which may induce symptoms on withdrawal of therapy.

Topics: Anti-Ulcer Agents; Bacterial Infections; Congenital Abnormalities; Dyspepsia; Fractures, Bone; Gastrins; Gastroenteritis; Gastroesophageal Reflux; Heartburn; Humans; Neoplasms; Omeprazole; Pneumonia; Proton Pump Inhibitors; Risk Factors; Time Factors; Vitamin B 12 Deficiency