Cytoskeletal actin reorganization in neutrophils from patients with localized juvenile periodontitis

Circulating inflammatory cell profiling and periodontitis: A systematic review and meta-analysis

Inflammation is a key driver of common noncommunicable diseases. Among common triggers of inflammation, chronic gingival inflammation (periodontitis) triggers a consistent humoral host inflammatory response, but little is known on its impact on circulating inflammatory cell profiles. We aimed to systematically appraise all the evidence linking periodontitis and its treatment to circulating inflammatory cell profiles. From 6 databases, 157 studies were eligible for qualitative synthesis and 29 studies for meta-analysis. Our meta-analysis showed that participants with periodontitis exhibited a significant mean increase in circulating CD4⁺ , CD4⁺ CD45RO⁺ , IFNγ-expressing CD4⁺ and CD8⁺ T cells, CD19⁺ CD27⁺ and CD5⁺ B cells, CD14⁺ CD16⁺ monocytes, and CD16⁺ neutrophils but decrease in CD8⁺ T and CD14⁺⁺ CD16^- monocytes. Our qualitative synthesis revealed that peripheral blood neutrophils of patients with periodontitis consistently showed elevated production of reactive oxygen species (ROS) when compared with those of healthy controls. Some evidence suggested that the treatment of periodontitis reversed the exaggerated ROS production, but limited and inconclusive data were found on several circulating inflammatory cell profiling. We conclude that periodontitis and its treatment are associated with minor but consistent alterations in circulating inflammatory cell profiles. These changes could represent key mechanisms explaining the association of periodontitis with other comorbidities such as cardiovascular disease, diabetes, and rheumatoid arthritis.

Impaired neutrophil directional chemotactic accuracy in chronic periodontitis patients

AIM

To investigate the chemotactic accuracy of peripheral blood neutrophils from patients with chronic periodontitis compared with matched healthy controls, before and after non-surgical periodontal therapy.

MATERIAL & METHODS

Neutrophils were isolated from patients and controls (n = 18) by density centrifugation. Using the Insall chamber and video microscopy, neutrophils were analysed for directional chemotaxis towards N-formyl-methionyl-leucyl-phenylalanine [fMLP (10 nM), or CXCL8 (200 ng/ml)]. Circular statistics were utilized for the analysis of cell movement.

RESULTS

Prior to treatment, neutrophils from patients with chronic periodontitis had significantly reduced speed, velocity and chemotactic accuracy compared to healthy controls for both chemoattractants. Following periodontal treatment, patient neutrophils continued to display reduced speed in response to both chemoattractants. However, velocity and accuracy were normalized for the weak chemoattractant CXCL8 while they remained significantly reduced for fMLP.

CONCLUSIONS

Chronic periodontitis is associated with reduced neutrophil chemotaxis, and this is only partially restored by successful treatment. Dysfunctional neutrophil chemotaxis may predispose patients with periodontitis to their disease by increasing tissue transit times, thus exacerbating neutrophil-mediated collateral host tissue damage.

Aggressive periodontitis: A clinico-hematological appraisal

Background:

Human leukocyte antigens (HLA) have been considered a candidate of genetic risk markers for aggressive periodontitis (AP). AP has also been associated with polymorphonuclear leukocyte (PMN) dysfunction. The role of monocyte subsets in AP has also not been completely explored. Therefore, the present study was undertaken to assess in, AP subjects, the possible association between defective PMN adhesion and β₂-integrin expression; defective neutrophil migration and actin polymerization level; the expression of ABO blood group and HLA antigen; and the percentage of CD14+ CD16+ monocytes and CD45RA monocytes. All these parameters have been compared with the subjects of chronic periodontitis (CP) and healthy controls.

Materials and Methods:

A total of 45 subjects of the age group 20-50 years, free from any known systemic disease, were divided into three groups – Group I - periodontally healthy control (n = 15), Group II - CP (n = 15) and Group III - AP (n = 15). Peripheral blood samples were collected. ABO grouping and HLA typing were performed. β₂-integrin expression, actin polymerization level and percentage of CD14+ CD16+ monocytes and CD45RA monocytes were estimated by fluorescence-activated cell sorter analysis.

Results:

Most of the subjects of AP belonged to the blood group AB, and an increased frequency of HLA-A30, CW1 and DR1 (P < 0.1) and B44 and DQ2 (P < 0.05) were also observed in this group. In the AP group, both average values (β₂-integrin and actin level) were significantly less than those of normal subjects (P < 0.001). The mean percentage of CD14+ CD16+ monocytes was found to be maximum in CP, followed by AP, and then in healthy subjects, while the mean percentage of CD45RA was maximum in AP, followed by CP, and then in healthy subjects.

Conclusions:

With the present state of knowledge from this study, a definite association of ABO blood groups and HLA phenotypes with periodontal diseases is yet to be established. Leukocytic functional defects were found in AP subjects. A statistically significant percentage of CD14+ CD16+ and CD45RA monocytes were found in AP subjects as compared with the normal control and CP groups.

Study of neutrophils isolated from peripheral blood of patients suffering from aggressive periodontitis at the cellular level: Receptors and cytoskeletal reorganization

BACKGROUND

Aggressive periodontitis (AgP) has been associated with polymorphonuclear leukocyte's (PMNL) dysfunction and periodontal pathogens possess variety of virulence factors that can impair PMNL's function. This study investigated the possible association between defective neutrophil adhesion and β(2) -integrin expression and defective neutrophil migration and actin polymerization level in the peripheral blood of neutrophils from the patients with AgP.

MATERIALS AND METHODS

A total of 30 individuals both male and female, age ranges between 13 - 48 years, were included in the study. Healthy controls (group I, n=10), chronic periodontitis (ChP) (group II, n=10), and AgP (group III, n=10), all without any systemic diseases and non-smokers, were recruited. Peripheral blood samples were taken and β(2) -integrin expression and actin polymerization levels were estimated by using fluorescence activated cell sorter analysis.

RESULTS

In AgP cases, both average values (β(2) -integrin and actin level) were significantly less than that of normal subjects (<0.001). But for ChP cases, only the average value of actin level is significantly lower than that of normal subjects (<0.025).

CONCLUSION

Lower β(2) -integrin expression in the AgP cases signifies lower neutrophil adhesion in AgP cases than normal, and the lower average value of actin polymerization for the AgP cases suggest lower migration capacity of neutrophils in AgP cases than normal.

A rapid flow cytometry assay for the assessment of calcium mobilization in human neutrophils in a small volume of lysed whole-blood

Flow cytometry-based methods have been developed to measure most neutrophil responses. The assessment of the mobilization of calcium, however, is routinely performed on neutrophils isolated from whole blood. This report describes a flow cytometry-based assay to measure the mobilization of calcium in neutrophils directly in whole blood. This method requires minimal sample manipulation, small volumes of blood and is performed in a short period of time. Both clinical and research laboratories will be able to assess neutrophil function and the quality of granulocyte preparations using a more time and cost effective calcium mobilization test.

Alterations of neutrophil f-actin kinetics by tobacco smoke: implications for periodontal diseases

Tobacco smoking is a major risk factor in the incidence and severity of periodontal diseases. Alterations of neutrophil function by short-term high levels of smoke during the act of smoking (acute smoke exposure) as well as long-term exposure to lower levels of tobacco substances in the bloodstream (chronic smoke exposure) may play a role in the pathogenesis of periodontal diseases in smokers. The polymerization and depolymerization of f-actin in response to infectious agents or inflammatory mediators is a critical process in a variety of neutrophil functions. In this study, we examined the effects of in vitro smoke exposure on neutrophils from smokers and non-smokers (which may be comparable to in vivo acute smoke exposure) and neutrophils from smokers not exposed to further in vitro smoke (which may be comparable to chronic smoke exposure) on f-actin kinetics. Peripheral neutrophils were isolated from seven healthy smoking subjects and seven healthy age-matched non-smoking subjects and exposed to 1-5 min of acute smoke in a smoke box system or not exposed to further smoke (baseline controls). Selected aliquots of neutrophils from control and 5-min exposures of acute smoke were then stimulated with the chemotactic peptide F-met-leu-phe at 10(-7) M for an additional 30-360 s. Cells were fixed and permeabilized, stained for f-actin with NBD phallacidin, and analyzed by flow cytometry. From baseline to 5 min of in vitro smoke exposure, there was a 38% decline in f-actin stain in non-smokers and a 30% decline in f-actin stain in smokers (p > 0.05) with f-actin values slightly higher in smokers than-non-smokers (p > 0.05). With F-met-leu-phe stimulation, both smokers and-non-smokers demonstrated a characteristic rise in f-actin stain from 0 to 120 s with a subsequent decline to baseline at 360 s and no significant differences in f-actin levels at any time of stimulation between groups. After preincubation with 5 min of in vitro smoke, the magnitude of rise in f-actin was less in both smokers and non-smokers when compared to cells not incubated with 5 min of smoke (p < 0.05 at 120 s for both smokers and non-smokers). F-actin values in smokers were higher than-non-smokers from 30 to 360 s of F-met-leu-phe exposure (p > 0.05). These results demonstrate that in vitro smoke exposure may impair normal f-actin kinetics. These alterations in f-actin kinetics may in turn affect other neutrophil functions which may impact on the pathogenesis of periodontal diseases in smokers.

Monocyte differentiation in localized juvenile periodontitis is skewed toward the dendritic cell phenotype

Several lines of evidence indicate that the monocytes of subjects with localized juvenile periodontitis (LJP) are functionally distinct from cells of age- and race-matched nonperiodontitis (NP) subjects. Among the abnormalities are the propensity to secrete large amounts of prostaglandin E(2) and the induction of immunoglobulin G2 (IgG2) antibodies. The experiments described here were performed to further characterize the LJP monocytes and to determine if these cells mature differently than NP monocytes. When adherent monocytes from LJP subjects were cultured in the presence of human serum, both macrophages and cells with the morphology of immature monocyte-derived dendritic cells (MDDC) were observed. Within 4 days the prevalence of the immature MDDC was approximately twofold higher in LJP cultures than in NP cultures. In addition to their dendritic morphology, these cells were CD11c(+) and CD14(-) or CD14(low) and stimulated potent autologous mixed leukocyte reactions, consistent with differentiation to the MDDC phenotype. Like LJP monocytes, cultures of MDDC generated with interleukin-4 and granulocyte-macrophage colony-stimulating factor selectively induced IgG2 in cultures of pokeweed mitogen-stimulated NP leukocytes. Together, these data suggest that the monocytes of LJP subjects have a propensity to differentiate into MDDC and that this differentiation may be related to the high levels of IgG2 that are observed in the sera of LJP subjects. As high levels of circulating IgG2 are correlated with less severe disease, the propensity of LJP monocytes to differentiate into MDDC may have important implications for both the host response against oral pathogens and the progression of LJP.

Nitric oxide synthase activity in neutrophils from patients with localized aggressive periodontitis

BACKGROUND

Localized aggressive periodontitis (LAgP) is associated with neutrophil dysfunction including defective chemotaxis and reduced calcium influx factor activity. Nitric oxide (NO) and its enzyme, nitric oxide synthase (NOS), have been suggested to be involved in chemotaxis. Some reports, however, were unable to detect either NO or NOS in human neutrophils. In this study, we focused on NOS activity in LAgP neutrophils and examined the involvement of NOS in chemotaxis of normal neutrophils and NOS activity in neutrophils from normal subjects and patients with LAgP.

METHODS

Neutrophils from 10 normal subjects and 10 LAgP patients were isolated from peripheral venous blood. Membrane associated-NOS (MA-NOS) and soluble NOS (S-NOS) were extracted from cells with or without FMLP stimulation. NOS activity was measured using the radiolabeled L-arginine to L-citrulline conversion assay.

RESULTS

N(omega)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS, significantly inhibited FMLP-induced chemotaxis (P<0.01) and dibutyryl cGMP, an activator of cGMP-dependent protein kinase, significantly attenuated the inhibition by L-NAME (P<0.01). Unstimulated and FMLP-stimulated MA-NOS activity in LAgP neutrophils was statistically significantly higher than that in normal neutrophils (P<0.05). S-NOS activity in LAgP neutrophils was higher than that in normal neutrophils.

CONCLUSIONS

This study suggests that NOS is present in human neutrophils and may be involved in FMLP-induced chemotaxis in normal neutrophils. NOS activity is increased in LAgP and is negatively correlated to chemotaxis response.

Defective calcium influx factor activity in neutrophils from patients with localized juvenile periodontitis

BACKGROUND

Localized juvenile periodontitis (LJP) is an early-onset periodontal disease associated with neutrophil dysfunction, including defective chemotaxis, reduced protein kinase C (PKC) activity, and reduced calcium entry. These observations are important because reduced availability of cytosolic-free calcium concentration in the cell will have detrimental consequences for the numerous cytosolic calcium concentration-dependent pathways. In particular, there is a direct relationship between Ca2+ flux and the cell activation enzyme PKC. In this report, we focused on the mechanism of calcium entry, investigating a newly described molecule, calcium influx factor (CIF). CIF is thought to be a second messenger for the opening of membrane calcium channels when intracellular calcium stores are depleted. We examined CIF activity in neutrophils from normal subjects and LJP patients.

METHODS

Neutrophils from 11 LJP patients, 3 adult periodontitis (AP) patients, and 12 normal subjects were isolated from peripheral venous blood. CIF was extracted with thapsigargin, a Ca2+-ATPase inhibitor, from isolated neutrophils and CIF activity measured using a 45CaCl2 uptake assay.

RESULTS

The CIF activity in neutrophils from LJP patients ranged from 98.9 to 281.5 units/mg protein (mean = 180.2 +/- 56.3) and from 291.9 to 755.5 units/mg protein (mean = 528.8 +/- 153.8) in non-periodontal disease controls. CIF activity in AP patients was also measured and found to be similar to controls. The CIF activity in LJP patients was statistically significantly reduced compared to that in normal subjects (P <0.001).

CONCLUSIONS

This study suggests that CIF activity may be an important determinant in neutrophil abnormalities in LJP.

The use of flow cytometry to measure neutrophil function

Neutrophils are important professional phagocytic cells that provide the host with a first line of defense against acute bacterial and fungal diseases and recurrent, severe or unusual infections are associated with inherited defects of neutrophil function. Furthermore, abundant evidence links inappropriate neutrophil-mediated tissue damage to the pathogenesis of conditions such as acute respiratory distress syndrome, septicemia with multiorgan failure, ischemia-reperfusion injury and rheumatoid arthritis. Flow cytometry has been increasingly used to evaluate the functional capabilities of neutrophils. In this review, we discuss the use of flow cytometry to assess neutrophil functional responses including calcium mobilization, F-actin assembly, adhesion, aggregation, degranulation, phagocytosis and reactive oxygen species (ROS) production. The use of flow cytometry to identify neutrophil priming is also discussed. The advantage of flow cytometry is that the majority of neutrophil functions can be measured using a small volume of whole blood that reduces artifactual changes in function caused by purification procedures. The advent of numerous new fluorochromes and multiparametric analysis allows the simultaneous measurement of several neutrophil functions in the same population of cells. Flow cytometric analysis provides a rapid screen for abnormalities of neutrophil function and reflects more accurately their behavior in vivo.