The response of human sulcular leucocytes to a chemotactic challenge. A new in vivo assay

Repeated measurement of crevicular fluid parameters at different sites

Few systematic studies have been made of amounts or of the composition of gingival crevicular fluid (GCF) from different sites or of the stability of GCF parameters over time. These data are needed to better understand the relation of GCF composition to periodontal health status. This report gives the volume and the amounts of lactate dehydrogenase (LDH), aryl sulfatase (AS) and neutrophil elastase (NE) for GCF collected from 6 samplings of 6 standard gingival sites in 11 young adult subjects over a 6-week period. Attachment loss (3 mm) was noted at only 1 of the 66 sites. The mean gingival index of the 11 subjects ranged from 0.33 to 1.67. The GCF volume and activity/sample of LDH and AS but not NE differed among subjects. However, differences among subjects were not found when the GCF enzyme activities were expressed as activity/microliter GCF. GCF volume and LDH, AS and NE activity all differed among the 6 sites when the activities were expressed as either quantity/sample or microliter GCF. These data show that differences among sites must be carefully considered in evaluation of GCF data. Fluid volume and LDH, AS and NE activity all varied from sampling to sampling. However, differences among sites were retained throughout the experimental period.

Effects of topical applications of meclofenamic acid and ibuprofen on bone loss, subgingival microbiota and gingival PMN response in the primate Macaca fascicularis

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to alter periodontitis in both animals and humans. This study was initiated in the nonhuman primate (Nhp) model to determine the effect of two NSAIDs on preexisting gingivitis, the conversion of gingivitis to periodontitis, the associated subgingival microbiota, and the gingival PMN response. Eighteen cynomolgus monkeys were divided into three groups and treated on a blind basis with ibuprofen 8%, meclofenamic acid 5%, or placebo applied topically 5 days/week for 20 wk. After 4 wk of treatment, periodontitis was initiated in one quadrant by the placement of silk ligatures. Clinical parameters, bone loss by densitometric analysis of radiographs (CADIA), and cultural microbiology of subgingival plaque were monitored. In situ PMN chemotaxis was assessed by quantitating the PMNs which entered the sulcus in response to a challenge with n-formyl-methionyl-leucyl-phenylalanine (FMLP). No significant differences in the clinical parameters were noted by treatment groups. Radiographic bone loss was detected in all experimental sites in placebo animals as compared with 67% and 44% for ibuprofen and meclofenamic acid animals, respectively. Mean CADIA scores/animal showed a significant loss in bone density for placebo at 6 and 16 wk, no change for ibuprofen animals, and a significant increase in density for meclofenamic acid animals. The microbiota of all groups changed with ligation consistent with previous reports of disease initiation in the Nhp.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of sequential sampling on crevicular fluid volume and enzyme activity

Gingival crevicular fluid (GCF) volume and constituents in static samples were compared to volume and constituents in subsequent GCF samples collected during a 60-min interval. Using deep intracrevicular placement of precut filter paper strips, GCF was collected from interproximal and facial sites from patients with gingivitis (N = 14; 28 interproximal sites, 28 facial sites) and chronic adult periodontitis (N = 11; 26 interproximal sites, 18 facial sites). The strips were inserted for 30 s at 0, 4, 8, 30 and 60 min. The amount of fluid on each strip was determined and microspectrophotometric techniques were used to assess cytoplasmic and lysosomal enzyme activity. Within each group of sites, mean GCF volume showed minimal fluctuation with repeated sampling. In contrast, the static GCF sample contained the greatest amount of total enzyme activity, and differences were detected between groups. The interproximal sites and the gingivitis-facial sites displayed a similar pattern of change in total enzyme activity during the test period. The highest total enzyme activity was observed in the first sample and decreased at 4 and 8 minutes. At 30 and 60 min, the amount of enzyme either remained at the level detected at 8 min, or displayed a mild tendency to recover towards baseline. A different pattern of total enzyme activity was observed for the periodontitis-facial sites, where a significant decrease was first observed at 30 min. Enzyme concentration was higher in the facial sites than the interproximal sites, and enzyme concentration was generally highest in the static samples. The concentration data, however, is difficult to interpret since a number of sites demonstrated a converted GCF volume of 0 microliter. Our data suggests that total enzyme activity and enzyme concentration are generally greater in the static GCF samples compared to subsequent samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophil chemotactic behaviour in patients with early-onset forms of periodontitis (I). Leading front analysis in Boyden chambers

Despite some reports to the contrary, it is generally assumed that early-onset forms of periodontal disease (including both juvenile and rapidly progressive periodontitis) are associated with a defect in neutrophil (PMN) chemotactic behaviour. Using the Boyden chamber technique and N-formyl-methionyl-leucylphenylalanine (FMLP) to assess locomotion by the leading front method, we have failed to show any evidence for such depressed PMN locomotion. Indeed, when PMN chemotaxis and chemokinesis are considered in response to a range of chemoattractant doses our results indicate significant enhancement of all but random locomotion. When taken together with other studies, our results suggest that PMNs from patients with early-onset periodontitis may show abnormal locomotory behaviour which can either be enhanced or reduced in nature. The extent to which these results reflect in vitro methodology in uncertain and, furthermore, their in vivo significance is unclear.

Transient behavior of a chemotaxis system modelling certain types of tissue inflammation

A spatially-distributed mathematical model for the inflammatory response to bacterial invasion of tissue is proposed which includes leukocyte motility and chemotaxis behavior and chemical mediator properties explicitly. This system involves three coupled nonlinear partial differential equations and so is not amenable to analysis. Using scaling arguments and singular perturbation techniques, an approximating system of two coupled nonlinear ordinary differential equations is developed. This system now permits analysis by phase plane methods. Using the approximating model, the dependence of the dynamic behavior of the inflammatory response upon key process parameters, including leukocyte chemotaxis, is studied.

Neutrophil chemotaxis in refractory cases of periodontitis

Refractory cases of periodontitis were assayed for chemotaxis of polymorphonuclear neutrophilic leukocytes using an in vivo assay. 9 refractory patients and 9 normal patients were studied. When cell counts were plotted against time, normal patients showed a single peak at 25-30 min after casein (chemo-attractant) challenge, whereas refractory patients showed 2 and 3 peaks of PMN's at varying time intervals. 5 of the refractory patients showed this pattern in tests of normal sulci as well as deep periodontal pockets. 4 of the refractory cases showed a double peak in tests of deep periodontal pockets. This suggests that some refractory cases have an intrinsic chemotactic defect of polymorphonuclear neutrophils while in others the defect may be a secondary phenomenon. It appears that patients with refractory periodontitis have the characteristic cell response that was reported for LJP.

Indicators of periodontal disease activity: an evaluation

It is becoming increasingly apparent that the traditional clinical criteria are inadequate for: determining active disease sites in periodontitis, monitoring quantitatively the response to therapy or measuring the degree of susceptibility to future breakdown. In an attempt to develop objective measures, a wide variety of studies have been undertaken using saliva, blood, plaque and gingival crevicular fluid (GCF) as the specimen source. Examination has included: specific bacteria and their products; host cells and their products (enzymatic and antibacterial, both immunologic and non-immunologic); products of tissue injury derived from local epithelial and connective tissues and bone. Although most of the work to date has failed to provide reliable aids to the clinician, refinements in techniques for sampling and the availability of more sophisticated analytic techniques give cause for optimism. Methods proposed for detection of disease-associated bacteria in subgingival plaque vary in their sensitivity and specificity. Dark field microscopy shows some correlation with existing disease; however, the limited specificity of this method imposes severe restrictions on its usefulness. Highly specific polyclonal and monoclonal antisera to suspected pathogens Bacteroides gingivalis and Actinobacillus actinomycetemcomitans have been developed and improved methods of identification of these microbes in plaque by ELISA immunofluorescence and flow cytometry are under development. With respect to the host response, a strong correlation between antibody patterns to specific bacteria and periodontal disease categories appears to be emerging. Although most studies have focused on serum antibody derived from peripheral blood, a shift to detection of local antibody response appears to be likely. Techniques of measurement that are exquisitely sensitive have been developed for detection of major immune recognition proteins such as antibody and complement in crevicular fluid. Research efforts attempting to correlate local antibody response to local disease activity are underway. Measurement of GCF flow rate, endotoxin, H2S, butyrate and a variety of enzymes (e.g., collagenase, arylsulfatase, B-glucuronidase) show good correlation with levels of gingivitis. In periodontitis, the most promising markers of tissue breakdown are prostaglandins of the E series, the enzymes collagenase and aspartate aminotransferase, sulfated glycosaminoglycans, osteoclastic activating factor and bone resorptive capacity of crevicular cells. Assay of the migration of crevicular leucocytes in vivo can serve as an indicator of a defect in host resistance.(ABSTRACT TRUNCATED AT 400 WORDS)

Local antibody responses in periodontal diseases

The relationship between local and systemic host antibody responses, colonization of subgingival plaque by periodontal disease-associated microorganisms and the progression of periodontal disease was assessed in 61 patients. Serum antibody levels to a battery of oral microorganisms were determined by an enzyme-linked immunosorbent assay (ELISA), and an organism to which each patient exhibited a significantly elevated IgG response was chosen for further study. To detect the presence of the specific microorganism, plaque samples were obtained and examined using a seroELISA. Static crevicular fluid (SCF) samples were also obtained from all teeth and analyzed for IgG antibody to the homologous organism. A modification of the standard ELISA using biotin and avidin allowed a 5- to 10-fold increase in sensitivity for detection of IgG antibody in serum and SCF. Comparison of the distribution of elevated SCF antibody and the presence of the corresponding microorganism in each patient showed that the proportion of agreement was 54 to 78% in the samples. Schematic representation of the temporal relationship between the organism, the host response and disease activity were prepared to explain the results obtained in investigations of these parameters and to provide a testable hypothetical framework for future studies.

In vivo assay of crevicular leukocyte migration. Its development and potential applications

Defects in neutrophil or polymorphonuclear leukocyte (PMNL) chemotaxis have been observed in a number of clinical conditions, including Down's syndrome and insulin-dependent diabetes mellitus (IDDM), which tend to be associated with severe forms of periodontal disease. In addition, impaired PMNL chemotaxis is frequently detected in individuals with localized juvenile periodontitis (LJP). The ability to monitor PMNL function in vivo at the gingival sulcus should therefore be useful as a diagnostic test. In this regard, we developed a technique which measures the response of PMNLs to a chemotactic agent, e.g., casein and N-formylmethionylleucylphenylalanine (N-FMLP) placed directly into gingival crevices. The development of the technique and its relationship to in vitro assays of chemotaxis are discussed, and data obtained from tests of the assay on control and streptozotocin-induced diabetic rats and human subjects with various periodontal diseases and IDDM are presented. As compared with healthy subjects and control animals, atypical (double peak) and reduced crevicular PMNL response patterns were observed during oral and systemic diseases. This suggests that the in vivo assay with appropriate modifications can be used diagnostically to assess PMNL migratory dysfunction and to identify individuals who may be susceptible to severe forms of periodontal disease.

Lactate dehydrogenase activity in gingival crevicular fluid collected with filter paper strips: analysis in subjects with non-inflamed and mildly inflamed gingiva

A previous study of lactate dehydrogenase (LDH) in gingival crevicular fluid (GCF) suggested that the concentration is 10 to 25 times that of serum (means = 2300 international units/1 versus 100 IU/1 for serum). That study used capillary tubes to collect microliter amounts of GCF. Since invasive collection techniques can influence GCF flow, we evaluated LDH activity in GCF collected by filter strips. GCF was collected in a standardized fashion from 10 subjects with mild inflammation (GI = 0.5-1.0) and 10 subjects without evidence of gingival inflammation (GI = 0). Our results indicate that LDH volume activity was greater for subjects with GI = 0 (means = 105,529 IU/1) than for subjects with GI = 0.5-1.0 (means = 77,661 IU/1), but the difference was not significant. LDH total unit activity was significantly greater in subjects with GI = 0.5-1.0 versus GI = 0 (means = 0.048 IU versus means = 0.0242 IU, P less than 0.0001). The relationship of LDH volume activity to GCF volume, the regression lines fit to the data, and calculation of LDH total unit activity were important for analysis of enzyme activity in GCF.

Periodontal diagnosis. Current status and future needs

This literature relating to current methods of periodontal diagnosis is reviewed. There exists a future need for objective diagnostic techniques which reflect the dynamics of periodontal disease activity.

Role of the polymorphonuclear leukocyte in periodontal health and disease

This review presents evidence for lysosomal enzymes being at least partly responsible for the tissue destruction seen in periodontal disease. However, many other inflammatory and immunologic mechanisms have been identified that can contribute to tissue destruction (Nisengard 1977). The relationship of PMN to the periodontal tissues is equivalent to the proverbial double-edged sword. The localized tissue destruction that may be due to the extracellular release of PMN enzymes in individuals with normal cell function must be weighed against the role of PMN in containment of gingival bacteria and their products. The consequences of qualitative and/or quantitative abnormalities of neutrophils are far more undesirable for the periodontium. It therefore seems logical to propose that the role of polymorphonuclear leukocytes in the gingival tissues is primarily a defensive one. The presence of neutrophils in the gingival crevice has been shown to reflect the inflammatory condition of the tissues. Due to their availability, it may prove beneficial to use gingival crevicular PMN activity as a reliable clinical index of disease activity. The development of appropriate tests to measure PMN may eventually lead to better diagnostic criteria, including the definition of active versus inactive disease.

In vivo crevicular leucocyte response in humans to a chemotactic challenge. Effects of periodontal diseases

An in vivo assay was recently developed to monitor the crevicular leucocyte response to chemotactic agents, e.g., casein and N-formyl peptides. This method was used to monitor humans with little or no gingival disease (C group), gingivitis (G group), chronic periodontitis (CP group) and localized juvenile periodontitis (LJP group). Casein (0.2 microliters, 2 mg/ml) was placed into an isolated gingival crevice of each subject with a calibrated wire loop and the time recorded (t = 0). Leucocytes were counted in crevicular washes (10 microliters) 15 minutes later and every 5 minutes thereafter up to t = 50 minutes. This protocol was repeated for the crevice of an adjacent tooth except that the crevicular fluid flow response to the chemotactic challenge was monitored. The C, G and CP subjects showed a similar pattern of response to the chemoattractant with a single "peak" of leucocytes at approximately t = 25 minutes. However, the peak cell count was much greater in the G and CP groups than in the C group. LJPs showed an abnormal pattern with two leucocyte peaks, one at approximately 25 minutes and the other at 45 minutes. Both peaks tended to be higher than the single peak seen in Cs but were significantly lower than that in Gs or CPs, even at similar levels of inflammation. In addition, the peak leucocyte response (to casein) in LJPs did not increase with increasing leucocyte counts in the unchallenged (resting) crevice, whereas a positive relationship was seen in the other groups of subjects. These data suggest that this new assay may provide important diagnostic information on in vivo neutrophil migration in the gingival crevice and on susceptibility to periodontal disease.

Effect of casein and whey-protein solutions on caries experience and feeding patterns of the rat

Casein (bovine milk phosphoprotein) at 2 per cent (w/v) in drinking water reduced the extent of fissure and smooth-surface caries of male Sprague-Dawley rats consuming a solid cariogenic diet. Whey protein (the non-phosphorylated protein group of bovine milk) also at 2 per cent (w/v) in the drinking water produced a smaller reduction and only of fissure caries. There was no significant difference in salivary-gland function (as determined by protein concentration), or in the amount or frequency of cariogenic diet consumed. The finding that a 2 per cent solution of whey protein reduced the extent of fissure caries in animals consuming a solid diet containing 26 per cent whey protein suggests that the anticariogenic action is mediated by the protein being in solution. These results suggest a topical anticariogenic action for dietary protein.

Demonstration of specific receptors for fluoresceinated casein on human neutrophils and monocytes using flow cytometry

Casein is chemotactic for human neutrophils (PMNs) and monocytes. The binding of fluorescein (FITC)-conjugated casein (mixture of alpha, beta, and kappa-casein) and purified alpha-casein to PMNs, monocytes, and lymphocytes was analyzed using flow cytometry. These studies demonstrate that 75-95% of PMNs and 46-85% of monocytes have membrane receptors for casein while lymphocytes lack these receptors. The binding of FITC-casein and FITC-alpha-casein was specific and was blocked only by unlabeled casein and alpha-casein, but not by ovalbumin, bovine or human serum albumin, beta-casomorphin, C5a, or formyl-methionyl-leucylphenylalanine (fMLP). The binding of FITC-casein was reversible when PMNs were stained with this fluorescent agent and subsequently incubated with unlabeled casein. Double-labeling studies of mononuclear cells using FITC-casein and the OKM1 monoclonal antibody in conjunction with a rhodamine conjugated anti-Ig second antibody demonstrate that mononuclear cells binding FITC-casein also stain with the OKM1 monoclonal antibody, indicating a specificity for monocytes.

An electron microscopic study of human neutrophils obtained by crevicular washing

The Application of electron microscopic methods to the study of neutrophils obtained from single sites by crevicular washing is described. A subsequent preliminary study of neutrophils and neutrophil-bacterial interactions at advanced lesions in patients with juvenile periodontitis and juvenile diabetes indicated that the neutrophils are phagocytically active at these sites. It is suggested that in vitro assays of crevicular neutrophil function may exaggerate the extent of impairment of phagocytosis because of cellular activity which has taken place prior to the time of sampling.