In vitro release of elastase from human blood and gingival crevicular neutrophils

Professional Oral Health Care at General Dental Clinic Reduces Postoperative Complications of Head and Neck Free-Flap Reconstruction Surgery

Background: Extensive resection and free-flap reconstruction surgery has become the standard treatment for locally advanced head and neck cancer. Surgical site infection (SSI) is one of the serious complications of this treatment. This study aimed to investigate the risk factor for onset of SSI, particularly focusing on whether preoperative professional oral health care in cooperation with general dental clinics is effective in reducing the occurrence of SSI.

Methods: From March 2003 to August 2011, 183 patients who underwent head and neck free-flap reconstructive surgery by the same plastic surgeon at Miyagi Cancer Center for Head and Neck Surgery were investigated retrospectively.

Results: Of the 183 patients, 135 and 48 were men and women, respectively, with a mean age of 62 (range, 29-82) years. The tumor was located in the oral cavity (n = 76), hypopharynx (n = 55), oropharynx (n = 28), and others (n = 24). Clinical stages were stage I/II in 18, stage III/IV in 164 patients, and benign tumor in one patient, based on UICC classification. SSI occurred in 66 patients (36.1%). Based on multivariate analysis, professional oral health care [P = 0.0076, odds ratio (OR) = 0.39] and radiation therapy history (P = 0.0214, OR = 2.820) were shown as factors that are significantly related to SSI.

Conclusion: This study identified history of radiation therapy as a significant risk factor for SSI from univariate and multivariate analysis and revealed that patients receiving preoperative professional oral health care at general dental clinics reduce the risk of SSI. Preoperative professional oral health care in cooperation with general dental clinics has been shown to reduce SSI of head and neck free-flap reconstructive surgery.

Neutrophils are the predominant infected phagocytic cells in the airways of patients with active pulmonary TB

BACKGROUND

The exact role of neutrophils in the pathogenesis of TB is poorly understood. Recent evidence suggests that neutrophils are not simply scavenging phagocytes in Mycobacterium tuberculosis (Mtb) infection.

METHODS

Three different types of clinical specimens from patients with active pulmonary TB who underwent lung surgery were examined: sputum, BAL fluid, and cavity contents. Differential cell separation and quantification were performed for intracellular and extracellular bacteria, and bacterial length was measured using microscopy.

RESULTS

Neutrophils were more abundant than macrophages in sputum (86.6% +/- 2.2% vs 8.4% +/- 1.3%) and in BAL fluid (78.8% +/- 5.8% vs 11.8% +/- 4.1%). Inside the cavity, lymphocytes (41.3% +/- 11.2%) were the most abundant cell type, followed by neutrophils (38.8% +/- 9.4%) and macrophages (19.5% +/- 7.5%). More intracellular bacilli were found in neutrophils than macrophages in sputum (67.6% +/- 5.6% vs 25.2% +/- 6.5%), in BAL fluid (65.1% +/- 14.4% vs 28.3% +/- 11.6%), and in cavities (61.8% +/- 13.3% vs 23.9% +/- 9.3%). The lengths of Mtb were shortest in cavities (1.9+/- 0.1 microm), followed by in sputum (2.9 +/- 0.1 microm) and in BAL fluid (3.6 +/- 0.2 microm).

CONCLUSIONS

Our results show that neutrophils are the predominant cell types infected with Mtb in patients with TB and that these intracellular bacteria appear to replicate rapidly. These results are consistent with a role for neutrophils in providing a permissive site for a final burst of active replication of the bacilli prior to transmission.

Neutrophil responses to Mycobacterium tuberculosis infection in genetically susceptible and resistant mice

The role of neutrophils in tuberculosis (TB) resistance and pathology is poorly understood. Neutrophil reactions are meant to target the offending pathogen but may lead to destruction of the host lung tissue, making the defending cells an enemy. Here, we show that mice of the I/St strain which are genetically susceptible to TB show an unusually high and prolonged neutrophil accumulation in their lungs after intratracheal infection. Compared to neutrophils from more resistant A/Sn mice, I/St neutrophils display an increased mobility and tissue influx, prolonged lifespan, low expression of the CD95 (Fas) apoptotic receptor, relative resistance to apoptosis, and an increased phagocytic capacity for mycobacteria. Segregation genetic analysis in (I/St x A/Sn)F2 hybrids indicates that the alleles of I/St origin at the chromosome 3 and 17 quantitative trait loci which are involved in the control of TB severity also determine a high level of neutrophil influx. These features, along with the poor ability of neutrophils to restrict mycobacterial growth compared to that of lung macrophages, indicate that the prevalence of neutrophils in TB inflammation contributes to the development of pathology, rather than protection of the host, and that neutrophils may play the role of a "Trojan horse" for mycobacteria.

Role of oral bacteria in respiratory infection

An association between oral conditions such as periodontal disease and several respiratory conditions has been noted. For example, recent evidence has suggested a central role for the oral cavity in the process of respiratory infection. Oral periodontopathic bacteria can be aspirated into the lung to cause aspiration pneumonia. The teeth may also serve as a reservoir for respiratory pathogen colonization and subsequent nosocomial pneumonia. Typical respiratory pathogens have been shown to colonize the dental plaque of hospitalized intensive care and nursing home patients. Once established in the mouth, these pathogens may be aspirated into the lung to cause infection. Other epidemiologic studies have noted a relationship between poor oral hygiene or periodontal bone loss and chronic obstructive pulmonary disease. Several mechanisms are proposed to explain the potential role of oral bacteria in the pathogenesis of respiratory infection: 1. aspiration of oral pathogens (such as Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, etc.) into the lung to cause infection; 2. periodontal disease-associated enzymes in saliva may modify mucosal surfaces to promote adhesion and colonization by respiratory pathogens, which are then aspirated into the lung; 3. periodontal disease-associated enzymes may destroy salivary pellicles on pathogenic bacteria to hinder their clearance from the mucosal surface; and 4. cytokines originating from periodontal tissues may alter respiratory epithelium to promote infection by respiratory pathogens.

Elastase in gingival crevicular fluid from smokers and non-smokers with chronic inflammatory periodontal disease

OBJECTIVE

To compare elastase concentrations in gingival crevicular fluid (GCF) from individual sites of smokers and non-smokers.

MATERIALS AND METHODS

Twelve pairs of smokers and non-smokers with untreated, moderate to advanced chronic inflammatory periodontal disease were matched for gender, age, ethnicity and the clinical and radiographic extent of disease. Durapore filter strip samples were collected over 30 s from two mesiopalatal sites on upper left posterior teeth. Samples were analysed for: 1) polymorphonuclear neutrophil leucocyte (PMNL) cell counts; 2) PMNL elastase-alpha 1-antitrypsin complex in the GCF supernatant by ELISA; and 3) functional elastase, free or bound to alpha 2-macroglobulin, estimated from activity against N-tert-butoxycarbonyl-alanyl-prolyl-norvalyl-p-chlorothiobenzyl ester in supernatant and lysates of GCF PMNLs.

RESULTS

There were no differences in disease parameters between groups except that bleeding on probing was less extensive in smokers (P<0.001). Cell counts and elastase content of crevicular PMNLs showed no differences between groups. Lower concentrations of elastase were found in GCF supernatants from smokers than non-smokers. This difference was observed for functional elastase (mean [s.d.] = 30.21 [17.60] against 73.77 [75.26] ng microliter(-1), p<0.05) and elastase complexed with alpha 1-antitrypsin (8.97 [6.54] ng microliter(-1) against 25.71 [22.07] ng microliter(-1), p<0.001).

CONCLUSIONS

Smokers have lower elastase concentrations in GCF than non-smokers. Further investigation is required to elucidate the underlying cause and its relationship with periodontal disease.

Ex vivo studies of polymorphonuclear neutrophils from patients with early-onset periodontitis (III). CR3 and LFA-1 expression by peripheral blood and gingival crevicular polymorphonuclear neutrophils

In this study, we assessed the LFA-1 (CD18/CD11a) and CR3 (CD18/CD11b) expression on peripheral polymorphonuclear leukocytes (PB-PMN) and crevicular fluid polymorphonuclear leukocytes (CF-PMN), by subjects with a healthy periodontium (n = 7), gingivitis (n = 8), early-onset periodontitis (n = 17) and adult periodontitis (n = 8). Using flow cytometry analysis, the %s of CD18, CD11a and CD11b positive cells and the absolute numbers of fluorescent molecules were determined. No significant difference could be found among the 4 groups, for these 2 kinds of parameters, in PB-PMN or CF-PMN. However, a great difference could be noted between the results obtained from PB-PMN and those obtained from CF-PMN. The %s of positive CF-PMN were significantly lower than those of PB-PMN for the 3 sub-units (p < 0.001). The levels of CD18 and CD11b expressed by CF-PMN were higher than those expressed by PB-PMN and the difference was significant for CD11b (p < 0.001). On the contrary, the level of CD11a expressed on CF-PMN was significantly lower than that expressed by PB-PMN (p < 0.001). Hence, our current results show that early-onset periodontitis PMN can be quite normal and this fact is not surprising insofar as, in our study, these cells were perfectly functional and all the subjects were in good health. We concluded that the analysis of the leukocyte adhesion receptors expression on PB-PMN does not appear useful for helping to establish a differential diagnosis between the different forms of periodontitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular and molecular effects of malnutrition and their relevance to periodontal diseases

In response to periodontal pathogens, the leukocytes (PMN) elaborate destructive oxidants, proteinases, and other factors. The balance between these factors, the antioxidants and endogenously synthesized antiproteinases determine the extent of periodontal damage. Malnutrition (PEM) is characterized by marked tissue depletion of the key antioxidant nutrients, including GSH (gamma-glutamyl-cysteinyl-glycine), and impaired acute-phase protein response (APR) to infections. The latter results in diminished production of the acute-phase proteins (APP). The APR plays a key role in promoting healing, and its deficit in PEM is due to impairment in the production and cellular action of the cytokines. Other features of malnutrition include inverted helper-suppressor T-cell ratio, histaminemia, hormonal imbalance with increased blood and saliva levels of free cortisol, and defective mucosal integrity. Malnutrition, particularly of the PEM type which usually involves concomitant deficiencies of several essential macro- and micronutrients, therefore has the potential to adversely influence the prognosis of periodontal infections.

Elastase release from gingival crevicular and peripheral neutrophils in periodontitis and health

The activity of elastase increases significantly in the gingival sulcus during inflammation. The release of this enzyme from crevicular and peripheral polymorphonuclear leucocytes (PMNs) was studied in seven patients with gingivitis, six with adult periodontitis, seven with rapidly progressive periodontitis and in nine healthy subjects. Peripheral PMNs were isolated from blood and crevicular PMNs from gingival washings. After preincubation with cytochalasin B, the same numbers of crevicular and peripheral cells were incubated either in phosphate-buffered saline (spontaneous release) or in the same buffer containing formyl methionyl-leucyl-phenyl-alanine (stimulated release). Elastase activity was measured in the supernatant by a fluorimetric technique. The results confirm that compared to peripheral PMNs, crevicular cells show a higher spontaneous release of elastase and a lower stimulated release. The activity of elastase released either spontaneously or after stimulation of crevicular cells was significantly lower in the controls as compared with cells obtained from patients with gingivitis or periodontitis. Crevicular PMNs collected from patients with deeper pockets appear to release larger amounts of elastase than those from controls.

Neutrophil dysfunction in rats with natural gingivitis

The functions of polymorphonuclear neutrophils (PMN) from SUS rats with naturally occurring gingivitis were examined by the luminol-dependent chemiluminescence (CL), adherence and bactericidal tests. SUS rats with pre-gingivitis showed lower CL responses of isolated PMNs and whole blood than control rats (RES rats). After plague formation and progression of gingivitis, the CL response gradually increased in SUS rats. RES rats had healthy gingiva and showed no increase in CL responses. Impaired PMN adherence was observed in SUS rats with pre-gingivitis but not in RES rats. PMNs from SUS rats with pre-gingivitis also showed lower bactericidal activity than those from RES rats. Dysfunction of PMNs might induce gingivitis as a result of decreased protection against periodontal pathogens and an elevated level of CL response can be recognized with progression of gingivitis.

An in vitro study of polymorphonuclear leucocyte-mediated injury to human gingival keratinocytes by periodontopathic bacterial extracts

Human gingival keratinocytes were cultured and, after the first passage, subjected to cell detachment assays with polymorphonuclear leucocytes (PMNs) and/or sonic extracts from Actinobacillus actinomycetemcomitans Y4, and Eikenella corrodens 1073. The effector-to-target cell ratio was 30:1. Bacterial extracts alone caused no disruption of keratinocyte monolayers. PMNs alone also caused only minimal detachment after 14 h incubation. Adding A. actinomycetemcomitans to the PMN-keratinocyte co-cultures at the concentration of 100 micrograms/ml caused dramatic cell detachment. The effect of A. actinomycetemcomitans was heat labile and not inhibited by polymyxin B. Cell detachment was inhibited by alpha 1-antitrypsin, whereas catalase and superoxide dismutase could not prevent it. No lysis of keratinocytes was observed after incubation, as judged by 51Cr release. E. corrodens had little effect even at the concentration of 1000 micrograms/ml. H2O2 and partially purified PMN elastase also caused detachment of keratinocytes. These data indicate that PMNs can cause non-lytic detachment of keratinocytes when interacting with certain bacteria.