Site-Specific Variations in Bone Mineral Density under Systemic Conditions Inducing Osteoporosis in Minipigs.

Matthias C Schulz,Bernd Stadlinger,Roland Jung,Uwe Eckelt,Eberhard Kuhlisch,Christian Stroszczynski,Ronald Mai,Jan Kowald,Lorenz C Hofbauer,Sven Estenfelder

doi:10.3389/fphys.2017.00426

Abstract

Osteoporosis is a systemic bone disease with an increasing prevalence in the elderly population. There is conflicting opinion about whether osteoporosis affects the alveolar bone of the jaws and whether it poses a risk to the osseointegration of dental implants. The aim of the present study was to evaluate the effects of systemic glucocorticoid administration on the jaw bone density of minipigs. Thirty-seven adult female minipigs were randomly divided into two groups. Quantitative computed tomography (QCT) was used to assess bone mineral density BMD of the lumbar spine as well as the mandible and maxilla, and blood was drawn. One group of minipigs initially received 1.0 mg prednisolone per kg body weight daily for 2 months. The dose was tapered to 0.5 mg per kg body weight per day thereafter. The animals in the other group served as controls and received placebo. QCT and blood analysis were repeated after 6 and 9 months. BMD was compared between the two groups by measuring Hounsfield units, and serum levels of several bone metabolic markers were also assessed. A decrease in BMD was observed in the jaws from baseline to 9 months. This was more pronounced in the prednisolone group. Statistically significant differences were reached for the mandible (p < 0.001) and the maxilla (p < 0.001). The administration of glucocorticoids reduced the BMD in the jaws of minipigs. The described model shows promise in the evaluation of osseointegration of dental implants in bone that is compromised by osteoporosis.

Highlights

Osteoporosis is a systemic disease that affects bone mass and architecture, increasing the risk of bone fractures (Rachner et al, 2011)
The serum level of ionic calcium and ionic phosphorus were analyzed by photometric test kits (CA2 and PHOS2)
The induction of an osteopenic state in the minipig by oral administration of glucocorticoids is predictable, and is minimally invasive when compared to surgical ovariectomy

Summary

Introduction

Osteoporosis is a systemic disease that affects bone mass and architecture, increasing the risk of bone fractures (Rachner et al, 2011). Osteoporosis is prevalent in the United States, Europe, and Japan, causing over 4.5 million fractures annually (WHO Scientific Group on the Assessment of Osteoporosis at Primary Health Care Level, 2004). As consequence of an aging population, an increasing number of people suffer from osteoporosis. The most common form of osteoporosis is post-menopausal osteoporosis in females, due to reduced estrogen levels. Other risk factors for the development of osteoporosis include patient age and long-term systemic exposure to exogenous glucocorticoids. The clinical diagnosis of osteoporosis is usually confirmed radiographically, via dual-energy X-ray absorptiometry (DXA)based bone densitometry (Felsenberg and Gowin, 1999) and, more recently, with high resolution quantitative computed tomography (hrQCT; Snedeker et al, 2006; Graeff et al, 2013)

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