Catalase activity in human healthy and inflamed dental pulps

AIM: To examine the catalase activity in clinically healthy and symptomatic human dental pulps to verify if an active defence system against oxidizing agents is present as a response to bacterial invasion. METHODOLOGY: Thirty-three systemically healthy patients, 18 females and 15 males (ages: 11.0-25.9 years; mean 18.8 +/- 3.6), were the source of the pulp tissue. The condition of the pulps was assessed using clinical and radiographic evaluations. The specimens were recovered by longitudinally grooving and splitting the teeth (if extracted) or during endodontic treatment, and were matched for age and sex between the healthy and inflamed specimen groups. Catalase activity was determined through spectrophotometric methods. RESULTS: Enzymatic activity was 1126 +/- 343 and 3074 +/- 698 mU mL(-1) x mg of total protein in the healthy and inflamed pulp tissue specimens, respectively. This difference was statistically significant (P<0.01). CONCLUSIONS: These results indicate a role for catalase during dental pulp inflammation in humans, and may represent an inherent biological defence system against reactive oxidants of this tissue.     

Aspartate aminotransferase activity in human healthy and inflamed dental pulps

Aspartate aminotransferase (AST) seems to be an important mediator of inflammatory processes. Its role in the progression and detection of inflammatory periodontal disease has been increasingly recognized in recent years. In the present study AST activity was analyzed in normal healthy human dental pulps, in reversible pulpitis, and in irreversible pulpitis. Enzymatic AST activity showed that the control values for the healthy pulps were 4.8 +/- 0.7 units/mg of pulp tissue. In reversible pulpitis specimens the AST activity increased to 7.98 +/- 2.1 units/mg of pulp tissue. In irreversible pulpitis specimens the values decreased to 2.28 +/- 1.7 units/mg of pulp tissue. Differences between the groups (control versus reversible pulpitis and reversible pulpitis versus irreversible pulpitis) were statistically significant (p = 0.0015). These results could point to a role of AST in the early events that lead to development of pulpal inflammation.     

Alkaline phosphatase activity in normal and inflamed dental pulps

Alkaline phosphatase (ALP) seems to be important in the formation of mineralized tissues. High levels of ALP have been demonstrated in dental pulp cells. In the present study ALP activity was analyzed in normal healthy human dental pulps, in reversible pulpitis, and in irreversible pulpitis. Enzymatic ALP control values for the normal healthy pulps were 110.96+/-20.93. In the reversible pulpitis specimens the ALP activity increased almost eight times to 853.6+/-148.27. In the irreversible pulpitis specimens the values decreased sharply to 137.15+/-21.28 and were roughly equivalent to those seen in normal healthy pulps. The differences between the groups (control vs. reversible pulpitis and reversible pulpitis vs. irreversible pulpitis) were statistically significant. These results could point to a role of ALP in the initial pulp response after injury.     

Ability of healthy and inflamed human dental pulp to reduce hydrogen peroxide

This study examined the defensive ability of human dental pulp against H2O2 in healthy and reversible and irreversible pulpitis tissues through determination of catalase activity by spectrophotometric methods. Thirty-five systemically healthy patients were donors of the pulp tissue, and pulp conditions were assessed using clinical and X-ray evaluations. Catalase activity was 1.61 +/- 0.23 U mg(-1) protein in the healthy tissues, 2.99 +/- 0.45 U mg(-1) protein in the reversible pulpitis tissues, and 2.44 +/- 467 mU mg(-1) protein in the irreversible pulpitis tissues. All differences between the groups were statistically significant. These results point to a role for catalase during dental pulp inflammation in humans, and therefore demonstrate an inherent biological defense system against reactive oxidants in human dental pulp.     

Matrix metalloproteinase levels and gelatinolytic activity in clinically healthy and inflamed human dental pulps

The role of matrix metalloproteinases (MMPs) in the breakdown of pulp tissue of teeth with severe caries has not yet been directly elucidated. This study was to determine the levels of selected MMPs and the overall gelatinolytic activity in clinically healthy and inflamed human dental pulps of 29 healthy subjects, aged 10-19 yr. Seventeen pulps were collected from subjects diagnosed with symptomatic pulpitis, and 18 control pulps were obtained from 12 subjects following premolar extraction for orthodontic reasons. The levels of MMP-1, MMP-2, MMP-3 and MMP-9 were determined with enzyme-linked immunosorbent assay. Densitometric analysis of gelatin zymograms was used to assay gelatinolytic activity in pulp supernatants. The MMP-1 levels were below the detection limit for both groups. Levels of MMP-2 and MMP-3 were significantly lower in symptomatic vs. clinically healthy pulps. In contrast, levels of MMP-9 in inflamed pulps were significantly higher than those recorded in clinically normal pulps. The overall gelatinolytic activity was elevated in inflamed pulps compared with healthy counterparts. Further, the gelatinolytic activity was positively correlated with MMP-9 levels. The data obtained suggest a key role of MMP-9 in the breakdown of inflamed human dental pulp tissue.     

Substance P and CGRP expression in dental pulps with irreversible pulpitis

The purpose of this study was to compare substance P (SP) and calcitonin gene-related peptide (CGRP) expression in pulp tissue with clinically diagnosed symptomatic and asymptomatic irreversible pulpitis. Healthy pulps acted as controls. Five normal pulps and 40 with irreversible pulpitis (20 symptomatic and 20 asymptomatic) were obtained from 45 different patients. SP and CGRP expression was determined by competition binding assays using enzyme immunoassay. anova and Mann–Whitney tests were used to ascertain if there were statistically significant differences between the groups. The results showed that neuropeptides were found in all pulp samples. The highest and the lowest expressions for SP and CGRP were found in symptomatic irreversible pulpitis and healthy pulps groups, respectively. The differences between healthy pulps and the groups of pulps having irreversible pulpitis were significant (P < 0.001). Although Mann–Whitney's post-hoc tests showed statistically significant differences in CGRP expression between two pulpitis groups (P < 0.05), differences in SP expression between symptomatic and asymptomatic irreversible pulpitis groups were not significant. This study demonstrated that the expression of CGRP and SP is significantly higher in pulps with irreversible pulpitis compared with healthy pulps.     

The effect of capsaicin on substance P expression in pulp tissue inflammation

AIM: To evaluate the effect of capsaicin on substance P (SP) expression during induced inflammation in rat pulp tissue. METHODOLOGY: Radioimmunoanalysis was used to measure SP levels in 36 mandibular molar pulps taken from six Wistar rats. Twelve samples were obtained from healthy pulps and used as negative control group. Another 12 samples were obtained after inducing inflammation with mechanical pulp exposure; these were used as the positive control group. Capsaicin was infiltrated into the inferior dental nerve in the experimental group and 12 samples were obtained after mechanical pulp exposure. RESULTS: The lowest SP expression was found in mechanically exposed pulps where capsaicin pretreatment had been carried out (0.028 ng mL(-1)), followed by healthy pulps (0.302 ng mL(-1)). The highest SP expression was found in mechanically exposed pulps with no capsaicin pretreatment (124 ng mL(-1)). The Kruskal-Wallis test showed statistically significant differences between the groups (P < 0.001). CONCLUSION: Inferior dental nerve infiltration with capsaicin reduces SP expression in dental pulp tissue in rats.     

Substance P receptor expression in healthy and inflamed human pulp tissue

AIM: To use radioreceptor analysis for comparing substance P (SP) receptor expression in human pulp tissue samples collected from teeth having a clinical diagnosis of acute irreversible pulpitis, healthy pulps and teeth with induced inflammation. METHODOLOGY: Five pulp samples were obtained from teeth having a clinical diagnosis of acute irreversible pulpitis. Another 10 pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic purposes. In five of these premolars inflammation was induced prior to pulp collection. All of the samples were processed and labelled with 125I-SP. Binding sites were identified by 125I-SP and standard SP competition assays. Kruskal-Wallis and Mann-Whitney (post-hoc) tests were used to establish statistically significant differences between the groups. RESULTS: Substance P receptor expression was found in all human pulp tissue samples. Most receptors were found in the group of pulps from teeth having a clinical diagnosis of acute irreversible pulpitis, followed by the group of pulps having induced inflammation. The least number of receptors was expressed in the group of healthy pulps. Statistical analysis revealed significant differences between the group of healthy pulp and both inflamed pulp groups (P < 0.01). CONCLUSION: Substance P receptor expression in human pulp tissue is significantly increased during inflammatory phenomena such as acute irreversible pulpitis.     

Calcitonin gene-related peptide receptor expression in healthy and inflamed human pulp tissue

AIM: To use radioreceptor analysis for comparing calcitonin gene-related peptide (CGRP) receptor expression in human pulp tissue samples collected from teeth having a clinical diagnosis of acute irreversible pulpitis, healthy pulps and teeth with induced inflammation. METHODOLOGY: Six pulp samples were obtained from teeth having a clinical diagnosis of acute irreversible pulpitis. Another eight pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic purposes. In four of these premolars, inflammation was induced prior to pulp collection. All the samples were processed and labelled with 125I-CGRP. Binding sites were identified by 125I-CGRP and standard CGRP competition assays. RESULTS: CGRP receptor expression was found in all human pulp tissue samples. Most receptors were found in the group of pulps from teeth having a clinical diagnosis of acute irreversible pulpitis, followed by the group of pulps having induced inflammation. The least number of receptors was expressed in the group of healthy pulps. The Kruskal-Wallis and Mann-Whitney (post-hoc) tests showed statistically significant differences between the groups (P < 0.05). CONCLUSION: CGRP receptor expression in human pulp tissue is significantly increased during inflammatory phenomena such as acute irreversible pulpitis.     

Quantitative analysis of catecholamines in human dental pulp

Catecholamines are important elements of neuroendocrine regulation, and their concentrations in dental pulp are of interest. Two groups of teeth were used in this study: (i) healthy teeth and (ii) periodontally diseased teeth. After the processing of dental pulp obtained from the extracted teeth, the samples were analyzed in a computer-controlled Merck-Hitachi HPLC system at 280 nm wavelength. The external and internal standard methods of the HPLC Manager Program were used for validation. In healthy teeth the norepinephrine level of dental pulp was 4.86 +/- 0.96 micrograms/g, whereas the epinephrine level was 8.1 +/- 1.18 micrograms/g. In periodontally diseased teeth norepinephrine and epinephrine levels were significantly higher (p < 0.01) at 13.98 +/- 21.13 micrograms/g and 1.42 +/- 0.32 micrograms/g, respectively. Dopamine could not be demonstrated in 87% of the pulps. Summing up we succeeded in demonstrating norepinephrine and epinephrine in human pulp, but in most cases we could not demonstrate dopamine. Further investigations are needed on pulp tissue infected because of caries.     

Tissue levels of immunoreactive substance P are increased in patients with irreversible pulpitis

Odontogenic pain often involves inflammation of dental pulp tissue. Dental pulp is highly innervated with a subpopulation of sensory neurons containing neuropeptides. Substance P, released from afferent fibers (e.g. nociceptors) is associated with the development of neurogenic inflammation. In this study, we tested the hypothesis that irreversible pulpitis is associated with increased activity of peptidergic neurons, as measured by increased pulpal levels of immunoreactive substance P (iSP). We determined in vivo pulpal levels of immunoreactive substance P in human teeth with a diagnosis of normal pulp or irreversible pulpitis using CMA/20 microdialysis probes inserted into vital pulps of 24 teeth from 21 patients. Probes were perfused with a modified Locke-Ringer's buffer and immunoreactive substance P levels in the dialysate were measured using a radioimmunoassay. Mean extracellular levels of immunoreactive substance P were significantly higher (>8-fold) in teeth diagnosed with irreversible pulpitis than immunoreactive substance P levels in dental pulp diagnosed as normal (147.7 +/- 34.0 pM versus 18.2 +/- 6.2 pM). These observations suggest that biochemical measures of inflammatory mediators exhibit significant change during irreversible pulpitis and may contribute to clinical signs and symptoms.     

Nitric oxide synthase in healthy and inflamed human dental pulp

Nitric oxide synthase (NOS) plays a significant role in the pathogenesis of pulpitis. In this study, we hypothesized the existence of endothelial (eNOS) and inducible (iNOS) enzyme isoforms in human dental pulp. Extracted third molar pulps were divided into groups based on clinical diagnosis: healthy, hyperemic, and irreversible pulpitis. We have localized the eNOS and iNOS by immunohistochemistry and have tested their mRNA expression by RT-PCR and protein levels by Western blots. eNOS is present in the endothelial cells and odontoblasts of the healthy pulp, but an elevation of eNOS mRNA and protein levels with a concomitant dilation of vessels was characteristic under pathological conditions. Healthy pulp tissue failed to exhibit any iNOS; however, acute inflammation enhanced the mRNA and protein levels of iNOS, mainly in the leukocytes. There are differences in localization and expression between eNOS and iNOS in healthy and inflamed dental pulp.     

Irreversible but not reversible pulpitis is associated with up-regulation of tumour necrosis factor-alpha gene expression in human pulp

AIM: To analyse the gene expression of tumour necrosis factor-alpha (TNF-alpha) in human dental pulps, under normal and inflammatory conditions and to examine the association between any observed alterations in the expression of this cytokine with the severity of the clinical symptoms. METHODOLOGY: Eighteen pulpal samples were obtained from single-rooted human teeth. Six of the teeth were normal (group A), six had been diagnosed with reversible pulpitis (group B), and the remaining six were from teeth diagnosed with irreversible pulpitis (group C). TNF-alpha gene expression was semi-quantitatively analysed in each sample with RT-PCR, and the results from each group of teeth were compared with the Kruskal-Wallis and Mann-Whitney tests. RESULTS: Tumour necrosis factor-alpha was detected in all three groups of dental pulp. Statistical analysis provided evidence of a significant increase of TNF-alpha gene expression associated with irreversible inflammation compared with healthy controls (P = 0.002). No such difference was detected in reversibly inflamed pulp in comparison to healthy teeth (P = 0.699). CONCLUSION: Tumour necrosis factor-alpha gene expression in inflamed human dental pulp tissue is positively associated with the severity of clinical symptoms.     

Diabetes induces metabolic alterations in dental pulp

Diabetes can interfere in tissue nutrition and can impair dental pulp metabolism. This disease causes oxidative stress in cells and tissues. However, little is known about the antioxidant system in the dental pulp of diabetics. Thus, it would be of importance to study this system in this tissue in order to verify possible alterations indicative of oxidative stress. The aim of this study was to evaluate some parameters of antioxidant system of the dental pulp of healthy (n = 8) and diabetic rats (n = 8). Diabetes was induced by streptozotocin in rats. Six weeks after diabetes induction, a pool of the dental pulp of the 4 incisors of each rat (healthy and diabetic) was used for the determination of total protein and sialic acid concentrations and catalase and peroxidase activities. Data were compared by a Student t test (p 相似文献   

Alkaline phosphatase activity in dental pulp of orthodontically treated teeth.

INTRODUCTION: The aim of this study was to examine alkaline phosphatase (ALP) activity in the dental pulp of orthodontically treated teeth. METHODS: Sixteen healthy subjects (mean age 17.0 +/-1.6 years) who required extraction of 4 first premolars for orthodontic reasons participated. One maxillary first premolar subjected to orthodontic force was the test tooth. The contralateral first premolar, bracketed but not subjected to mechanical stress, was the control tooth. After a week of treatment, the first premolars were extracted and the dental pulp removed from the teeth. ALP activity was determined spectrophotometrically and the results expressed as units/liter per milligram of pulp tissue [U/(L x mg)]. RESULTS: ALP activity was 89 +/- 26 U/(L x mg) in the test teeth and 142 +/- 33 U/(L x mg) in the control teeth. The difference between the groups was statistically significant (P < .01). CONCLUSIONS: Orthodontic treatment can lead to significant early-phase reduction in ALP activity in human dental pulp tissue.     

Increased interleukin-8 expression in inflamed human dental pulps.

OBJECTIVE: Elevated levels of interleukin-8, a potent chemoattractant and activator of neutrophils, are associated with infectious and inflammatory diseases. However, little is known about interleukin-8 expression in human dental pulp. The purpose of this study was to determine whether tissue levels of interleukin-8 are elevated in irreversibly inflamed human pulps. STUDY DESIGN: Experimental samples were from teeth clinically diagnosed with irreversible pulpitis (diseased pulps). Controls were from freshly extracted, caries-free third molars (normal pulps). Samples were subjected to enzyme-linked immunosorbent assay and/or immunohistochemical analysis with specific antibodies to interleukin-8. RESULTS: The enzyme-linked immunosorbent assay studies showed elevated levels of interleukin-8 in diseased pulps (mean, 1.82+/-0.79 pg/mL/microg protein), as compared to detectable interleukin-8 levels in samples from normal pulps (mean, 0.08+/-0.04 pg/mL/microg protein; P<.05). Immunohistochemical analyses demonstrated that diseased samples exhibited a higher density of localized interleukin-8 staining in areas with heavy infiltration of inflammatory cells. In contrast, normal pulps showed negative or weak interleukin-8 staining. CONCLUSIONS: Interleukin-8 concentration was higher in pulps diagnosed with irreversible pulpitis; only negligible amounts of interleukin-8 were present in normal pulps.     

Vascular endothelial growth factor (VEGF) expression in healthy and inflamed human dental pulps.

Vascular endothelial growth factor (VEGF) is a glycoprotein that has the capability to increase vascular proliferation and permeability. VEGF has been found to be expressed in several different types of tumors, and it may contribute to the progression of malignant tumors. Immunostaining for VEGF and factor VIII was performed in normal healthy pulps and in irreversible pulpitis. In both cases the vessels were always positive for VEGF. Our immunohistochemical data show that the expression of VEGF was strongly positive in the inflammatory infiltrate in irreversible pulpitis. VEGF expression in the stromal cells in healthy pulps ranged from 20 to 100% (with a mean of 68.82), and in irreversible pulpitis ranged from 0 to 100% (with a mean of 62.35%); this difference was statistically significant (p = 0.05). This down-regulation in the stromal cells in irreversible pulpitis could be due to the presence, in a low compliance system such as the dental pulp, of inflammatory infiltrate. VEGF is probably a factor implicated in the etiology and progression of pulpitis. The microvessel density in healthy pulps was 90.00 +/- 27.5, while, in irreversible pulpitis, it was 56.68 +/- 21.15. This difference was statistically significant (p = 0.001). The decrease in microvessel density in irreversible pulpitis could be related to failing vascular function and blood flow decrease.     

Immunolocalization of bone extracellular matrix proteins (type I collagen,osteonectin and bone sialoprotein) in human dental pulp and cultured pulp cells

AIM: To simultaneously analyse the expression of type I collagen, osteonectin and bone sialoprotein (BSP) in human dental pulp of different ages. METHODOLOGY: Cultured dental pulp fibroblasts (FP1 cell line), pulps from dental germs with incomplete root formation (n = 4) and pulps of erupted teeth with total root formation (n = 4) were used. Bone proteins were searched by immunohistochemistry and immunofluorescence using polyclonal antibodies and compared among the three groups assessed. RESULTS: Immunohistochemistry detected the three proteins in dental pulp tissue, as it labelled extracellular matrix, predentine and odontoblasts. The BSP label was weaker, when compared to both type I collagen and osteonectin. The presence of type I collagen was more evident in pulps from erupted teeth, when compared to germ dental pulps. On the other hand, a strong expression of osteonectin in germ dental pulps was observed. CONCLUSIONS: Regardless of the degree of maturation, dental pulps present type I collagen, osteonectin and BSP in the extracellular matrix (ECM) and in the odontoblastic layer. Thus, the results suggest that these proteins are related to the production and mineralization of dentine.