Classical and Alternative Activation of Rat Microglia Treated with Ultrapure Porphyromonas gingivalis Lipopolysaccharide In Vitro.

The possible relationship between periodontal disease resulting from the infection of gingival tissue by the Gram-negative bacterium Porphyromonas gingivalis (P. gingivalis) and the development of neuroinflammation remains under investigation. Recently, P. gingivalis lipopolysaccharide (LPS) was reported in the human brain, thus suggesting it might activate brain microglia, a cell type participating in neuroinflammation. We tested the hypothesis of whether in vitro exposure to ultrapure P. gingivalis LPS may result in classical and alternative activation phenotypes of rat microglia, with the concomitant release of cytokines and chemokines, as well as superoxide anion (O2-), thromboxane B2 (TXB2), and matrix metalloprotease-9 (MMP-9). After an 18-h exposure of microglia to P. gingivalis LPS, the concentration-dependent responses were the following: 0.1-100 ng/mL P. gingivalis LPS increased O2- generation, with reduced inflammatory mediator generation; 1000-10,000 ng/mL P. gingivalis LPS generated MMP-9, macrophage inflammatory protein 1α (MIP-1α/CCL3), macrophage inflammatory protein-2 (MIP-2/CXCL2) release and significant O2- generation; 100,000 ng/mL P. gingivalis LPS sustained O2- production, maintained MMP-9, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) release, and triggered elevated levels of MIP-1α/CCL3, MIP-2/CXCL2, and cytokine-induced neutrophil chemoattractant 1 (CINC-1/CXCL-1), with a very low release of lactic dehydrogenase (LDH). Although P. gingivalis LPS was less potent than Escherichia coli (E. coli) LPS in stimulating TXB2, MMP-9, IL-6 and interleukin 10 (IL-10) generation, we observed that it appeared more efficacious in enhancing the release of O2-, TNF-α, MIP-1α/CCL3, MIP-2/CXCL2 and CINC-1/CXCL-1. Our results provide support to our research hypothesis because an 18-h in vitro stimulation with ultrapure P. gingivalis LPS resulted in the classical and alternative activation of rat brain microglia and the concomitant release of cytokines and chemokines.

Monitoring treatment of central precocious puberty using basal luteinizing hormone levels and practical considerations for dosing with a 3-month leuprolide acetate formulation.

BACKGROUND: Peak gonadotropin-releasing hormone or agonist (GnRHa) stimulated luteinizing hormone (LH) testing with leuprolide acetate (LA) is commonly used to document suppression during therapy for central precocious puberty (CPP). The objective of the study was to investigate suitability of using basal LH levels to monitor GnRHa treatment and to determine optimal transition from 1-month to 3-month LA formulations via a post hoc analysis of a randomized, open-label, 6-month study. METHODS: A total of 42 children with CPP, pretreated with 7.5-, 11.25-, or 15-mg 1-month LA formulations were randomized to 11.25- or 30-mg 3-month LA. Basal LH/peak-stimulated LH levels were measured at weeks 0, 4, 8 and 12. Positive/negative predictive values and sensitivities/specificities were determined for basal LH vs. LH-stimulation results. RESULTS: Pretreatment with any 1-month formulation for the most part did not affect continuation of suppression after transitioning to 3-month formulation (mean peak-stimulated LH levels remained < 4 IU/L). Basal LH predicted suppression escape (basal LH-level cutoff ≥ 0.6 IU/L predicted 70% of those failing suppression). Tolerability was similar, regardless of dose. CONCLUSIONS: Our data indicate that a basal level of <0.60 IU/L is adequate for monitoring suppression approximately two-thirds of the time. Furthermore, the effectiveness and safety of 3-month LA treatments are not influenced by previous CPP therapies.