Catalase activity in human healthy and inflamed dental pulps

Chemokine‑like receptor 1‑positive cells are present in the odontoblast layer in tooth tissue in rats and humans

Cluster of differentiation (CD)44 is a marker of dental pulp stem cells and is involved in odontoblast differentiation and calcification. Chemokine-like receptor 1 (CMKLR1), also known as chemerin receptor 23 (ChemR23) is also expressed in odontoblasts and dental pulp stem cells and is involved in inflammation suppression and tooth regeneration. Resolvin E1, a bioactive lipid, is a CMKLR1 ligand that mediates the chemerin-CMKLR1 interaction and suppresses pulpal inflammation. The present study clarified the intracellular and tissue localization of CD44 and CMKLR1 by immunohistochemical staining of normal pulp and pulp with pulpitis from 12-week-old male Wistar rat teeth or human teeth. In addition, the localization of CD44 and CMKLR1 in human dental pulp stem cells was observed by immunofluorescence staining. The present study also examined the involvement of resolvin E1 in inhibiting inflammation and calcification by western blotting. CD44- and CMKLR1-positive cells were confirmed in the odontoblast layer in normal dental pulp of rats and humans. CD44 was mainly localized in the cell membrane and CMKLR1 was mainly found in the cytoplasm of human dental pulp stem cells. CMKLR1 was also confirmed in the odontoblast layer in rats and humans with pulpitis but CD44 was not present. Following treatment of dental pulp stem cells with lipoteichoic acid, which imitates Gram-positive bacterial infection, resolvin E1 did not suppress the expression of cyclooxygenase-2 or of the odontoblast differentiation marker, dentin sialophosphoprotein. Furthermore, resolvin E1 induced the differentiation of dental pulp stem cells into odontoblasts even in the presence of the inflammatory stimulus.

Effects of aging and inflammation on catalase activity in human dental pulp

OBJECTIVES

In this study, it was aimed to examine the catalase activity in clinically healthy and caries-related inflamed symptomatic human dental pulps of young and old individuals.

DESIGN

Sixty pulp samples from young and old healthy donors, were collected depending on pulpal status. 48 samples were used for spectrophotometric analysis and 12 samples for immunohistochemistry. Healthy pulps were maintained from non-carries, extracted third molars. Reversible and irreversible pulpitis samples were obtained by pulp extirpation during endodontic treatment. Following homogenization catalase enzyme activity was determined by spectrophotometry. Additionally, two pulp tissue samples from each group were fixed and evaluated for catalase immunoreactivity.

RESULTS

Catalase enzyme activity in old healthy pulp samples were significantly higher than healthy young samples (p ≤ 0.05). Reversible and irreversible pulpitis samples indicated significantly decreased activity compared to healthy samples in elderly group (p ≤ 0.05). Young reversible pulpitis samples showed significantly increased catalase activity when compared to irreversible pulpitis and the reversible pulpitis samples in elderly group (p ≤ 0.05). Immunohistochemical evaluation indicated that there was intense catalase immunoreactivity in young patients with reversible pulpitis compared with reversible pulpitis in elderly group. However, weak immunoreactivity was observed in young irreversible pulpitis and elderly reversible pulpitis samples.

CONCLUSIONS

The pulp tissues presented different levels of catalase activities against pulpitis and aging.

A Mini Review: The Potential Biomarkers for Non-invasive Diagnosis of Pulpal Inflammation

For assessing the adequacy of vital pulp therapy for an inflamed pulp, the use of non-invasive diagnostic tools is necessary to avoid further damage to the teeth. Detection of biomarkers that are indicative of the inflammatory status in pulp can be a promising tool for this purpose. These biomarkers need to be reliably correlated with pulpal inflammation and to be easily detected without pulp exposure. This mini-review article aims to review biomarkers that are present in gingival crevicular fluid (GCF) in inflamed pulp conditions. Several studies have reported the availability of various biomarkers including cytokines, proteases, elastase, neuropeptides, and growth factors. Non-invasive pulpal diagnostic methods will be useful as well to determine reversibility, irreversibility, or necrosis of inflamed pulp. These types of molecular diagnoses via analyzing the proteome have revolutionized the medical field, and are one of the most promising empirical methodologies that a clinician can utilize for the proactive identification of pulpal disease.

Randomized controlled clinical trial on bleaching sensitivity and whitening efficacy of hydrogen peroxide versus combinations of hydrogen peroxide and ozone

The clinical efficacy regarding bleaching sensitivity and tooth shade lightening using a standard hydrogen peroxide (H₂O₂) bleaching gel was compared with the additional use of ozone either before or after application of H₂O₂. Using computer-generated tables, 45 participants were randomly allocated into three groups (n = 15 each) in this investigator-driven, single-centre trial. In Group 1, upper anterior teeth were bleached using ozone (produced via a healOzone X4 device) for 60 seconds, then 38% H₂O₂ for 20 minutes; in Group 2, 38% H₂O₂ application (20 min) was followed by ozone (60 s); air produced by the healOzone machine (60 s) followed by 38% H₂O₂ (20 min) was used in Group 3 (control). Bleaching sensitivity was evaluated via visual analogue scales, and a treatment-blinded reader objectively recorded tooth shades using a colorimeter before and 24 hours after bleaching (at α = 0.05). The H₂O₂/ozone combination did not result in pain sensations, while both ozone/H₂O₂ and H₂O₂ alone increased bleaching sensitivity (p < 0.001). Teeth achieved lighter shades (higher L*/lower b* values) after bleaching in all groups (p < 0.001), while Ozone boosted lighter tooth shades, irrespective of its use before or after H₂O₂ (p < 0.05). Due to the complimentary effects, applying ozone after H₂O₂ seems preferable for bleaching.

Biological Markers for Pulpal Inflammation: A Systematic Review

Background and Objective

Pulpitis is mainly caused by an opportunistic infection of the pulp space with commensal oral microorganisms. Depending on the state of inflammation, different treatment regimes are currently advocated. Predictable vital pulp therapy depends on accurate determination of the pulpal status that will allow repair to occur. The role of several players of the host response in pulpitis is well documented: cytokines, proteases, inflammatory mediators, growth factors, antimicrobial peptides and others contribute to pulpal defense mechanisms; these factors may serve as biomarkers that indicate the status of the pulp. Therefore, the aim of this systematic review was to evaluate the presence of biomarkers in pulpitis.

Methods

The electronic databases of MEDLINE, EMBASE, Scopus and other sources were searched for English and non-English articles published through February 2015. Two independent reviewers extracted information regarding study design, tissue or analyte used, outcome measures, results and conclusions for each article. The quality of the included studies was assessed using a modification of the Newcastle-Ottawa-Scale.

Results and Conclusions

From the initial 847 publications evaluated, a total of 57 articles were included in this review. In general, irreversible pulpitis was associated with different expression of various biomarkers compared to normal controls. These biomarkers were significantly expressed not only in pulp tissue, but also in gingival crevicular fluid that can be collected non-invasively, and in dentin fluid that can be analyzed without extirpating the entire pulpal tissue. Such data may then be used to accurately differentiate diseased from healthy pulp tissue. The interplay of pulpal biomarkers and their potential use for a more accurate and biologically based diagnostic tool in endodontics is envisaged.

A PerR-like protein involved in response to oxidative stress in the extreme bacterium Deinococcus radiodurans

Response and defense systems against reactive oxygen species (ROS) contribute to the remarkable resistance of Deinococcus radiodurans to oxidative stress induced by oxidants or radiation. However, mechanisms involved in ROS response and defense systems of D. radiodurans are not well understood. Fur family proteins are important in ROS response. Only a single Fur homolog is predicted by sequence similarity in the current D. radiodurans genome database. Our bioinformatics analysis demonstrated an additional guanine nucleotide in the genome of D. radiodurans that is not in the database, leading to the discovery of another Fur homolog DrPerR. Gene disruption mutant of DrPerR showed enhanced resistance to hydrogen peroxide (H2O2) and increased catalase activity in cell extracts. Real-time PCR results indicated that DrPerR functions as a repressor of the catalase gene katE. Meanwhile, derepression of dps (DNA-binding proteins from starved cells) gene under H2O2 stress by DrPerR point to its regulatory role in metal ions hemostasis. Thus, DrPerR might function as a Fur homolog protein which is involved in ROS response and defense. These results help clarify the complicated regulatory network that responds to ROS stress in D. radiodurans.

A novel OxyR sensor and regulator of hydrogen peroxide stress with one cysteine residue in Deinococcus radiodurans

In bacteria, OxyR is a peroxide sensor and transcription regulator, which can sense the presence of reactive oxygen species and induce antioxidant system. When the cells are exposed to H₂O₂, OxyR protein is activated via the formation of a disulfide bond between the two conserved cysteine residues (C199 and C208). In Deinococcus radiodurans, a previously unreported special characteristic of DrOxyR (DR0615) is found with only one conserved cysteine. dr0615 gene mutant is hypersensitive to H₂O₂, but only a little to ionizing radiation. Site-directed mutagenesis and subsequent in vivo functional analyses revealed that the conserved cysteine (C210) is necessary for sensing H₂O₂, but its mutation did not alter the binding characteristics of OxyR on DNA. Under oxidant stress, DrOxyR is oxidized to sulfenic acid form, which can be reduced by reducing reagents. In addition, quantitative real-time PCR and global transcription profile results showed that OxyR is not only a transcriptional activator (e.g., katE, drb0125), but also a transcriptional repressor (e.g., dps, mntH). Because OxyR regulates Mn and Fe ion transporter genes, Mn/Fe ion ratio is changed in dr0615 mutant, suggesting that the genes involved in Mn/Fe ion homeostasis, and the genes involved in antioxidant mechanism are highly cooperative under extremely oxidant stress. In conclusion, these findings expand the OxyR family, which could be divided into two classes: typical 2-Cys OxyR and 1-Cys OxyR.

Attenuation of ischemia/reperfusion-induced intestinal injury by oleo-resin from Copaifera langsdorffii in rats

Copaifera langsdorffii oleo-resin (CLOR) is a reputed herbal medicine used to combat gastrointestinal functional disorders. Our previous studies show that CLOR prevents gastric ulceration and promotes wound healing. This study examined the effects of CLOR on intestinal damage associated with mesenteric ischemia/reperfusion in rat. Wistar albino rats were divided into four groups of six in each. Group 1: Sham operated, Group 2: Vehicle + 45 min of ischemia followed by 60 min reperfusion (I/R), Groups 3 and 4: I/R + CLOR (200 and 400 mg /kg, p.o., respectively). All treatments were given 24 h, 12 h and 2 h before I/R. Animals were sacrificed at the end of reperfusion period and ileal tissue samples were obtained for biochemical analysis. Myeloperoxidase (MPO), an index of polymorphonuclear leukocytes; malondialdehyde (MDA), an end product of lipoperoxidation; catalase (CAT), an antioxidant enzyme; reduced glutathione (GSH), a key antioxidant; and nitrite, a marker of nitric oxide (NO) production were determined in ileum homogenates. The results show that I/R produces a significant increase in MDA content, MPO, and CAT activities with a significant decrease in GSH and an elevation in nitrite production, as compared to sham control. CLOR treatment caused significant attenuations in I/R-associated increases of MPO, MDA and CAT activities and on nitrite level. Besides, CLOR could effectively prevent the I/R-associated depletion of GSH. The data indicate that the oleo-resin has a protective action against I/R-induced intestinal tissue damage, which appeared to be, at least in part, due to an antioxidant and anti-lipid peroxidation mechanism.