Bisphosphonate-related osteonecrosis of the jaw in four Nordic countries and an indication of under-reporting.

OBJECTIVE: To assess reported cases of bisphosphonate-related osteonecrosis of the jaw (BONJ) to Medicines Agencies (MAs) in four Nordic countries and to compare the Norwegian MA data with BONJ cases retrieved through an e-mail survey to Oral and Maxillofacial Surgeons (OMS) in Norway. MATERIAL AND METHODS: BONJ cases reported to the national MAs in each country from January 1st 2003 to September 30th 2010 were collected. An e-mail survey was sent to all active members of the Norwegian Association of Oral and Maxillofacial Surgeons (n = 54) included questions on total BONJ cases seen in practice and route of drug administration during January 1st 2003 to December 31st 2009. RESULTS: In total, 253 BONJ cases were reported to the MAs; 39 in Denmark, 44 in Finland, 51 in Norway and 119 in Sweden. These figures result in cumulative incidences (multiplied by 100,000) of 0.7, 0.8, 1.1 and 1.3, respectively. Intravenous administration was reported in 169 of the cases. The e-mail survey resulted in 35 responses reporting 214 BONJ cases, 4-times more cases than reported to the MA. CONCLUSIONS: Cumulative incidence of cases reported in this study differs to some degree in the four Nordic countries (Denmark < Finland < Norway < Sweden). In Norway, almost the same number of BONJ cases were reported through the questionnaire by OMS as in all four countries together (214 by OMSs vs 254 to MAs) and included a high number after per oral administration. The present results indicate a notable under-reporting in Norway and most likely in other Nordic countries.

Alendronate and omeprazole in combination reduce angiogenic and growth signals from osteoblasts.

OBJECTIVE: Due to gastrointestinal side effects of oral bisphosphonates (BPs), proton pump inhibitors (PPIs) are often prescribed. PPIs may enhance the risk of osteonecrosis of the jaw, a rare side effect of BPs. Therefore, the objective of this study was to evaluate the effects of the oral BP alendronate (ALN) and the PPI omeprazole (OME) alone and in combination on primary human osteoblasts and gingival fibroblasts in vitro. METHODS: Human gingival fibroblasts and normal human osteoblasts were incubated with either 5 µM of ALN or 1 µM of OME, or ALN + OME for 1, 3, 7 or 14 days. Effect on viability was evaluated by the lactate dehydrogenase activity in the medium and on proliferation by quantifying 3H-thymidin incorporation. Multianalyte profiling of proteins in cell culture media was performed using the Luminex 200TM system to assess the effect on selected bone markers and cytokines. RESULTS: The proliferation of osteoblasts and fibroblasts was reduced upon exposure to ALN + OME. ALN induced an early, temporary rise in markers of inflammation, and OME and ALN + OME promoted a transient decline. An initial increase in IL-13 occurred after exposure to all three options, whereas ALN + OME promoted IL-8 release after 7 days. OME and ALN + OME promoted a transient reduction in vascular endothelial growth factor (VEGF) from osteoblasts, whereas ALN and ALN + OME induced a late rise in VEGF from fibroblasts. Osteoprotegerin release was enhanced by ALN and suppressed by OME and ALN + OME. CONCLUSIONS: ALN + OME seemed to exaggerate the negative effects of each drug alone on human osteoblasts and gingival fibroblasts. The anti-proliferative effects, modulation of inflammation and impairment of angiogenesis, may induce unfavorable conditions in periodontal tissue facilitating development of osteonecrosis.