J Bone Miner Res. 2022 Nov 19. doi: 10.1002/jbmr.4740. Online ahead of print.
ABSTRACT
Osteoporosis has traditionally been characterized by underlying endocrine mechanisms though evidence indicates a role of inflammation in its pathophysiology. Lipopolysaccharide (LPS), a component of gram-negative bacteria that reside in the intestines, can be released into circulation and stimulate the immune system, upregulating bone resorption. Exogenous LPS is used in rodent models to study the effect of systemic inflammation on bone and to date a variety of different doses, routes, and durations of LPS administration have been used. The study objective was to assess if systemic administration of LPS induces inflammatory bone loss in rodent models. A systematic search of Medline and 4 other databases resulted in a total of 110 studies that met the inclusion criteria. Pooled standardized mean differences (SMD) and corresponding 95% confidence intervals (CI) with a random-effects meta-analyses was used for bone volume fraction (BV/TV) and volumetric bone mineral density (vBMD). Heterogeneity was quantified using the I2 statistic. Shorter-term (<2 weeks) and longer-term (>2 weeks) LPS interventions were analyzed separately because of intractable study design differences. BV/TV was significantly reduced in both shorter- (SMD = -3.79%, 95% CI [-4.20, -3.38], I2 62%; p < 0.01) and longer-term (SMD = -1.50%, 95% CI [-2.00, -1.00], I2 78%; p < 0.01) studies. vBMD was also reduced in both shorter- (SMD = -3.11%, 95% CI [-3.78, -2.44]; I2 72%; p < 0.01) and longer-term (SMD = -3.49%, 95% CI [-4.94, -2.04], I2 82%; p < 0.01) studies. In both groups, regardless of duration LPS negatively impacted trabecular bone structure, but not cortical bone structure, and an upregulation in bone resorption demonstrated by bone cell staining and serum biomarkers was reported. This suggests systemically delivered exogenous LPS in rodents is a viable model for studying inflammatory bone loss, particularly in trabecular bone. This article is protected by copyright. All rights reserved.
PMID:36401814 | DOI:10.1002/jbmr.4740
