Expression of FcgammaRs and mCD14 on polymorphonuclear neutrophils and monocytes may determine periodontal infection

Distal Consequences of Oral Inflammation

Periodontitis is an incredibly prevalent chronic inflammatory disease, which results in the destruction of tooth supporting structures. However, in addition to causing tooth and alveolar bone loss, this oral inflammatory disease has been shown to contribute to disease states and inflammatory pathology at sites distant from the oral cavity. Epidemiological and experimental studies have linked periodontitis to the development and/or exacerbation of a plethora of other chronic diseases ranging from rheumatoid arthritis to Alzheimer's disease. Such studies highlight how the inflammatory status of the oral cavity can have a profound impact on systemic health. In this review we discuss the disease states impacted by periodontitis and explore potential mechanisms whereby oral inflammation could promote loss of homeostasis at distant sites.

Novel Assay To Characterize Neutrophil Responses to Oral Biofilms

Neutrophils, the most numerous leukocytes, play an important role in maintaining oral health through interactions with oral microbial biofilms. Both neutrophil hyperactivity and the bacterial subversion of neutrophil responses can cause inflammation-mediated tissue damage like that seen in periodontal disease. We describe here an assay that assesses neutrophil activation responses to monospecies biofilm bacteria in vitro based on the surface expression of cluster of differentiation (CD) markers associated with various neutrophil functions. Most of what we know about neutrophil responses to bacteria is based on in vitro assays that use planktonic bacteria and isolated/preactivated neutrophils, which makes interpretation of the neutrophil responses to bacteria a challenge. An understanding of how neutrophils differentially interact with and respond to commensal and pathogenic oral bacteria is necessary in order to further understand the neutrophil's role in maintaining oral health and the pathogenesis of periodontal disease. In this study, a flow cytometry-based in vitro assay was developed to characterize neutrophil activation states based on CD marker expressions in response to oral monospecies bacterial biofilms. Using this approach, changes in CD marker expressions in response to specific prominent oral commensal and pathogenic bacteria were assayed. Several functional assays, including assays for phagocytosis, production of reactive oxygen species, activation of the transcription factor Nrf2, neutrophil extracellular trap formation, and myeloperoxidase release, were also performed to correlate neutrophil function with CD marker expression. Our results demonstrate that neutrophils display bacterial species-specific responses. This assay can be used to characterize how specific biofilms alter specific neutrophil pathways associated with their activation.

Epistatic Association of CD14 and NOTCH2 Genetic Polymorphisms with Biliary Atresia in a Southern Chinese Population

Biliary atresia (BA) is the most common cause of endstage liver disease in infants with poor prognosis and high mortality. The etiology of BA is still unknown, but the genetic factors have been considered as an important player in BA. We investigated the association of two cis-regulated variants in CD14 (rs2569190) and NOTCH2 (rs835576) with BA susceptibility, using the largest case-control cohort, totaling 506 BA patients and 1,473 healthy controls in a Southern Chinese population. Significant epistatic interaction between the two variants in our samples was observed (p = 8.1E-03; OR = 2.78; 95% CI: 1.32-5.88). The expression of CD14 and NOTCH2 in the BA group was consistently lower than that in the control (CC) group (0.31 ± 0.02 versus 1.00 ± 0.14; p < 0.001), which might be related to the genetic susceptibility of the genes awaiting further validation.

Endotoxin and CD14 in the progression of biliary atresia

Background

Biliary atresia (BA) is a typical cholestatic neonatal disease, characterized by obliteration of intra- and/or extra-hepatic bile ducts. However, the mechanisms contributing to the pathogenesis of BA remain uncertain. Because of decreased bile flow, infectious complications and damaging endotoxemia occur frequently in patients with BA. The aim of this study was to investigate endotoxin levels in patients with BA and the relation of these levels with the expression of the endotoxin receptor, CD14.

Methods

The plasma levels of endotoxin and soluble CD14 were measured with a pyrochrome Limulus amebocyte lysate assay and enzyme-linked immunosorbent assay in patients with early-stage BA when they received the Kasai procedure (KP), in patients who were jaundice-free post-KP and followed-up at the outpatient department, in patients with late-stage BA when they received liver transplantation, and in patients with choledochal cysts. The correlation of CD14 expression with endotoxin levels in rats following common bile duct ligation was investigated.

Results

The results demonstrated a significantly higher hepatic CD14 mRNA and soluble CD14 plasma levels in patients with early-stage BA relative to those with late-stage BA. However, plasma endotoxin levels were significantly higher in both the early and late stages of BA relative to controls. In rat model, the results demonstrated that both endotoxin and CD14 levels were significantly increased in liver tissues of rats following bile duct ligation.

Conclusions

The significant increase in plasma endotoxin and soluble CD14 levels during BA implies a possible involvement of endotoxin stimulated CD14 production by hepatocytes in the early stage of BA for removal of endotoxin; whereas, endotoxin signaling likely induced liver injury and impaired soluble CD14 synthesis in the late stages of BA.

Soluble CD14 in periodontitis

Lipopolysaccharide (LPS) binds to soluble (s)CD14. We investigated which factors contribute to variations in sCD14 levels in periodontitis, a chronic infectious disease of tooth-supporting tissues associated with endotoxemia and leading to inflammation and subsequently loss of teeth. The sCD14 levels were determined by ELISA in healthy controls (n=57) and untreated patients (59 moderate and 46 severe) and their relation with markers of systemic inflammation (C-reactive protein levels, and leukocyte, neutrophil and lymphocyte counts) was assessed. Anti-Aggregatibacter actinomycetemcomitans and anti-Porphyromonas gingivalis IgG levels were established by ELISA and CD14(-260) genotype was determined in a TaqMan allelic discrimination assay. Increased levels of sCD14 were more frequent among periodontitis patients (P=0.026) and showed a severity-dependence with increasing levels of periodontal breakdown (P=0.008). In patients, levels of sCD14 correlated positively with CRP (P=0.043), leukocyte numbers (P=0.011) and negatively with anti-A. actinomycetemcomitans IgG (P=0.007). In a multivariate analysis, sCD14 levels were predicted by ethnicity, age, educational level, and in Caucasian subjects also by the severity of periodontal destruction, but not by anti-P. gingivalis IgG or the CD14(-260) genotype. Periodontitis is associated with elevated levels of sCD14.