Effects of local anesthesia on substance P and CGRP content of the human dental pulp

Functional expression of oxytocin receptors in pulp-dentin complex

Dental pulp-derived stromal cells (DPSCs) are a crucial cell population for maintaining the tissue integrity of the pulp-dentin complex. The oxytocin receptor (OXTR), a member of the G protein-coupled receptor (GPCR) superfamily, plays versatile roles in diverse biological contexts. However, the role of OXTR in dental pulp has not yet been fully understood. Here, we demonstrate the biological functions and significance of OXTR in DPSCs through a multidisciplinary approach. Microarray data of 494 GPCR genes revealed high OXTR expression in human DPSCs (hDPSCs). Blocking OXTR activity increased the expression of osteogenic and odontogenic marker genes, promoting hDPSC differentiation. Additionally, we found that OXTR is involved in extracellular matrix (ECM) remodeling through the regulation of the gene expression related to ECM homeostasis. We further demonstrated that these genetic changes are mediated by trascriptional activity of Yes-associated protein (YAP). Based on the results, a preclinical experiment was performed using an animal model, demonstrating that the application of an OXTR inhibitor to damaged pulp induced significant hard tissue formation. These results provide new insight into the oxytocin-OXTR system in the regenerative process of pulp-dentin complex.

Comparison of Neurokinin A, Substance P, Interleukin 8, and Matrix Metalloproteinase-8 Changes in Pulp tissue and Gingival Crevicular Fluid Samples of Healthy and Symptomatic Irreversible Pulpitis Teeth

INTRODUTION

The aim of this study was to compare levels of neurokinin A (NKA), substance P (SP), interleukin (IL)-8, and matrix metalloproteinase-8 (MMP-8) in pulp tissue and gingival crevicular fluid (GCF) samples of healthy and symptomatic irreversible pulpitis teeth.

METHODS

Forty patients diagnosed with healthy and symptomatic irreversible pulpitis teeth were included in this study. NKA, SP, IL-8, and MMP-8 levels were measured using the enzyme-linked immunosorbent assay test after pulp and GCF samples were obtained from healthy (n = 20) and symptomatic irreversible pulpitis teeth (n = 20). GCF sampling of 40 teeth was repeated 1 week later. Routine root canal treatment procedures of the teeth were performed, and the treatment process was completed. As a control group, GCF samples were taken from the contralateral teeth in both groups. Statistical analysis was performed using dependent and independent t tests, analysis of variance, Kruskal-Wallis, Mann-Whitney U tests, and Pearson correlation analysis.

RESULTS

Comparing the groups, all mediator levels were significantly higher in the pulp samples in the pulpitis group compared with the healthy group (NKA: P < .001, SP: P = .005, IL-8: P < .001, and MMP-8: P < .001). Likewise, in the pulpitis group, all mediator levels were significantly higher in the first GCF samples compared with the healthy group (NKA: P = .01, SP: P < .001, IL-8: P = .001, and MMP-8: P < .001).

CONCLUSIONS

It was observed that NKA, SP, IL-8, and MMP-8 increased significantly in pulp tissue and GCF specimens of symptomatic irreversible pulpitis teeth compared with pulp tissue and GCF specimens of healthy teeth. Second, it was determined that NKA, SP, IL-8, and MMP-8 levels decreased significantly in GCF samples in teeth diagnosed with symptomatic irreversible pulpitis 1 week after the removal of inflamed pulp. Finally, SP, IL-8, and MMP-8 levels were found to be higher in pulp tissue samples of the patients with symptomatic irreversible pulpitis with higher pain scores than those with low pain scores.

Comparative study of substance P and neurokinin A in gingival crevicular fluid of healthy and painful carious permanent teeth

BACKGROUND

It is shown that neuropeptides can be transported from pulp chamber to periodontal ligament through apical foramen and accessory canals. Therefore, clinical pulpal pain leads to expression of preinflammatory neuropeptides such as substance P (SP) and neurokinin A (NKA) in gingival crevicular fluid (GCF). This study aimed to evaluate levels of SP and NKA in GCF of carious and healthy permanent teeth, comparatively.

MATERIALS AND METHODS

This cross-sectional study was performed on twenty children referred to Department of Pediatric Dentistry, Tehran University of Medical Sciences, who had a painful permanent first molar. Sampling was done by sterile paper cone from GCF of the mentioned teeth and the intact tooth of the other side of the jaw in the same patient. Values of SP and NKA were measured by ELISA test.

RESULTS

The mean concentration of SP in GCF of painful carious and healthy teeth was 2.65 ± 0.56 and 1.83 ± 0.65 pcgr/ml, respectively. This value was 2.29 ± 0.29 and 1.61 ± 0.35 pcgr/ml for NKA concentration in carious and healthy teeth as well.

CONCLUSION

Significant higher levels of both SP and NKA in GCF of painful carious teeth were observed, which is in line with previous studies' findings.

Experimentally Induced Pulpal Lesion and Substance P Expression: Effect of Ketoprofen-A Preliminary Study

Objectives. To evaluate substance P (SP) and the effect of ketoprofen administration, a nonsteroidal anti-inflammatory drug (NSAID), on SP in the pulp of upper third molars with experimentally induced pulpal lesion. Materials and Methods. A sample of 20 young systemically healthy adults of both sexes, nonsmokers, with a healthy upper third molar to extract for orthodontic purposes, was selected. Prior to the procedure, an inflammatory process was generated by mechanical exposure of the pulp. After 15 minutes, the pulp was collected using a sterile barbed broach. SP levels were determined by using a commercially available enzyme immunoassay (ELISA) kit. The subjects were randomly divided into two groups: group 1 received a dose of ketoprofen 30 minutes prior to the experimental procedure. The subjects of group 2 did not receive any kind of drug administration. The patients were asked to complete a diary on the postoperative pain. Results. No statistically significant difference could be detected in SP expression between the two groups. In group 1, pain manifestation was significantly delayed in comparison with group 2. Conclusions. Preventive administration of ketoprofen did not significantly affect the pulpal levels of SP but resulted in a significantly postponed manifestation of pain after extraction.

Cancer surgery: how may anesthesia influence outcome?

OBJECTIVE

To review the published literature regarding the effects of anesthesia on cancer surgery to prevent tumor cell proliferation/migration or induce apoptosis.

BACKGROUND

Surgery is the main treatment for potentially curable solid tumors, but most cancer-related deaths in patients who have received previous surgical treatment are caused by metastatic disease. There is increasing evidence that anesthetic technique has the potential to affect long-term outcome after cancer surgery.

METHODS

This work reviews the English published literature that was obtained by performing a search of the PubMed database up to January 2014. We selected articles that provided evidence or reviewed the possible actions of anesthetics on cancer cells or the influence of anesthesia in recurrence/outcome.

RESULTS

Inhaled anesthetics induce immunosuppression and activate inflammatory cascade activation, whereas propofol has a protective action. Opioids might promote cancer recurrence and metastasis. In vitro and in vivo studies have demonstrated that local anesthetics inhibit proliferation and migration of cancer cells and induce apoptosis.

CONCLUSIONS

Anesthesiologists should follow current best clinical practice and include all strategies that effectively decrease pain and attenuate stress. Regional anesthesia and multimodal analgesia, adding anti-inflammatory drugs, play an unquestionable role in the control of perioperative pain and may improve recurrence-free survival.

Peripheral mechanisms of dental pain: the role of substance P

Current evidence supports the central role of neuropeptides in the molecular mechanisms underlying dental pain. In particular, substance P, a neuropeptide produced in neuron cell bodies localised in dorsal root and trigeminal ganglia, contributes to the transmission and maintenance of noxious stimuli and inflammatory processes. The major role of substance P in the onset of dental pain and inflammation is increasingly being recognised. Well-grounded experimental and clinical observations have documented an increase in substance P concentration in patients affected by caries, pulpitis, or granulomas and in those undergoing standard orthodontic or orthodontic/dental care procedures. This paper focuses on the role of substance P in the induction and maintenance of inflammation and dental pain, in order to define future lines of research for the evaluation of therapeutic strategies aimed at modulating the complex effects of this mediator in oral tissues.

The effect of different vasoconstrictors and local anesthetic solutions on substance P expression in human dental pulp

The purpose of this study was to quantify the effect of the infiltration injection of different vasoconstrictor and anesthetic solutions on substance P (SP) expression in healthy human dental pulp. Thirty pulp samples were obtained from healthy upper premolars in which extraction was indicated for orthodontic reasons and were randomly assigned into three groups of 10 samples each: 2% lidocaine with 1:80,000 epinephrine (Lido group), 3% Prilocaine with 1:200000 felypressin (Prilo group); and 4% Prilocaine without vasoconstrictor (Prilo-no-VC group). All teeth were extracted 10 minutes after anesthetic application. Pulp samples were processed and SP was measured by radioimmunoassay. SP expression for the Lido, Prilo, and Prilo-no-VC groups were 616.49, 663.76, and 760.79 pmol/mg pulp tissue, respectively. Analysis of variance showed statistically significant differences between groups (p = 0.001). Tukey Honestly Significant Difference (HSD) post hoc tests showed significant statistical differences between the Prilo-no-VC group and the Lido group (p < 0.01) and between the Prilo-no-VC group and the Prilo group (p < 0.05). It can be concluded that infiltration injection of local anesthetics with vasoconstrictor attenuate SP expression in human dental pulp.

The effect of tooth bleaching on substance P expression in human dental pulp

The purpose of this study was to quantify the effect of tooth bleaching on substance P (SP) expression in healthy human dental pulp. Forty pulp samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Thirty of these premolars were assigned into three different tooth-bleaching protocols: group 1 (n = 10): Opalescence Xtra Boost (Ultradent Products, South Jordan, UT) (38% H(2)O(2)) for 15 minutes; group 2 (n = 10): Lase Peroxide (DMC, Brazil) (35% H(2)O(2)) activated with infrared laser diode (Biolux; BioArt, Brazil) for 3 minutes, and group 3 (n = 10): Zoom! Whitening System (Discuss Dental, Culver City, CA) (25% H(2)O(2)) light activated for 20 minutes. The remaining 10 healthy premolars serve as a control group. Teeth were anesthetized immediately after bleaching and were extracted 10 minutes later. All pulp samples were processed and SP was measured by radioimmunoassay. Greater SP expression was found in the Zoom! Whitening System, followed by the Lase Peroxide group, Opalescence Xtra Boost, and the lower SP values were for the control group. Analysis of variance showed statistically significant differences between groups (p = 0.0001). Tukey HSD post hoc tests showed significant differences in the light (p < 0.01) and laser (p < 0.05) activated bleaching systems when compared with control values. It can be concluded that light- and laser-activated tooth-bleaching systems increase SP expression in human dental pulp significantly higher than normal values.

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.

Quantification of neuropeptides (calcitonin gene-related peptide, substance P, neurokinin A, neuropeptide Y and vasoactive intestinal polypeptide) expressed in healthy and inflamed human dental pulp

AIM

To quantify the expression of calcitonin gene-related peptide (CGRP), substance P (SP), neurokinin A (NKA), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) in healthy and inflamed human dental pulp tissue.

METHODOLOGY

Six pulp samples were obtained from teeth having a clinical diagnosis of acute irreversible pulpitis. Another 12 pulp samples were obtained from premolars where extraction was indicated for orthodontic purposes. In six of these premolar teeth inflammation was induced by mechanical pulp exposure prior to sample collection. All samples were processed and 125I-labelled; neuropeptides were quantified by competition assays. ANOVA and Mann-Whitney's (post hoc) tests were used to establish statistically significant differences between the groups.

RESULTS

Expression of five neuropeptides was found in all human pulp samples. Statistical analysis revealed a significantly higher (P < 0.05) expression of CGRP, SP, NKA and NPY in both inflammatory conditions compared with healthy pulp control values. VIP expression remained stable during the inflammatory conditions.

CONCLUSION

Expression of CGRP, SP and NKA released from C-fibres and NPY released from sympathetic fibres is significantly higher in the inflamed human pulp compared with healthy pulp. Expression of VIP released from parasympathetic fibres is not increased during the inflammatory conditions of human dental pulp.

The effect of cavity preparation on substance P expression in human dental pulp

Substance P (SP) plays an important role during neurogenic inflammation of dental pulp. The purpose of this study was to use a radioimmunoassay for determining the effect of cavity preparation on SP expression in healthy human dental pulp. Ten pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. Deep cavity preparation (<1 mm remaining dentine thickness) was performed before extraction in five of these bicuspids. All samples were processed and I-SP labeled; SP was quantified by competition assay. The results revealed SP expression in all human pulp samples. Mann-Whitney's U test revealed statistically significant higher expression in pulp from teeth where cavity preparation had been performed compared to control values (p < 0.05). These findings suggest that SP is released during common dental procedures (such as cavity preparation) and its expression may have an important clinical significance in terms of experiencing inflammation and pain.

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.

Current treatment options for acute pain

The pain that accompanies surgical procedures remains prevalent and is an aspect of the perioperative experience that generates the greatest concern for patients about to undergo surgery. There is also a growing recognition of the extent that acute painful experiences can lead to longer-term painful consequences, even when tissue healing appears to be complete. The neurobiologic basis of this has been partially elucidated. The key observations are that multiple sites and multiple receptors collectively contribute, and that noxious stimuli initiate a cascade of events that sensitise the nervous system so that subsequent noxious stimuli are perceived with greater intensity and even previously non-painful stimuli can be painful. Incorporating these observations into effective perioperative regimens designed to limit acute pain and its consequences leads to a multimodal pre-emptive approach to acute pain management. Acute perioperative pain is an ideal setting for the use of pre-emptive analgesic techniques because the timing of noxious stimuli is known in advance and surgical sensitisation of the nervous system is ongoing despite adequate levels of general anaesthesia with volatile anaesthetics. The relevant neurobiology of pain, reviewed in this article, is the basis for advocating an aggressive, multimodal, pre-emptive approach to acute pain therapy throughout the entire perioperative period. A growing body of outcome studies demonstrates the long-term efficacy of this approach.

Quantitative analysis of substance P, neurokinin A and calcitonin gene-related peptide in pulp tissue from painful and healthy human teeth

AIM

The purpose of this study was to investigate the levels of substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) in painful and healthy human dental pulps.

METHODOLOGY

Forty-six samples of pulp tissue were collected from extracted or endodontically treated painful teeth and 20 from clinically healthy teeth extracted for orthodontic reasons. All pulp samples were boiled in 0.5 m acetic acid for 10 min, centrifuged and the supernatant collected. SP, NKA and CGRP levels were measured using radioimmunoassay.

RESULTS

Substance P and CGRP were present in all samples and NKA was detected in 96% of the pulps. CGRP was present in much higher concentrations than SP and NKA in both painful and non-painful teeth. The painful teeth had significantly higher concentrations of SP (P = 0.02), NKA (P < 0.001) and CGRP (P = 0.03) than non-painful teeth. The concentration of CGRP was significantly higher in the pulps of smokers compared with non-smokers (P = 0.02).

CONCLUSIONS

Elevated levels of these neuropeptides in pulps from painful teeth indicate that they may play an important role in the process of pulpal inflammation and pain. Further investigation of the association between these neuropeptides and pulpal status may help to improve our understanding of pulpal inflammation and dental pain.

Vital pulp therapy for complicated crown fracture of permanent canine teeth in dogs: a three-year retrospective study

A 36-month retrospective study compared the results of vital pulp therapy based on the duration of pulp exposure for complicated crown fracture of 97 permanent canine teeth in 76 dogs. Postoperative oral and radiographic examinations were performed at 3, 12, and 36-months following treatment. Based on the 36-month postoperative examinations 88.2%, 41.4 %, and 23.5% of teeth were vital when treated within 48-hours, 1-week, and 3-weeks of pulp exposure, respectively. There was a significant difference in the incidence of tooth vitality between groups. The duration of pulp exposure following complicated crown fracture influenced the success of vital pulp therapy. Vital pulp therapy should be performed as soon as possible following traumatic pulp exposure.

Identification of G-protein coupled receptor subunits in normal human dental pulp

To respond appropriately to their environment, dental pulp cells must integrate informational input from multiple ligands, such as neuropeptides, growth factors, and vasoactive amines. These ligands act through multiple intracellular signaling pathways. G-protein coupled receptor subunits play a major role in this process, providing a mechanism for coordinated regulation of both messengers and effectors. Increasing number of neuropeptides have been found in pulpal tissue. However, there is no data about molecular identification of G-protein subunits in human dental pulp. To identify the postreceptor mechanism involved in dental pulp cell signal transduction, we performed a Western blot analysis of different G-protein subunits. Biopsy specimens of human dental pulp were prepared and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by analysis with appropriate antibodies. We detected G alpha q/alpha 11, short and long forms of G alpha s, beta common, Gio-3, and Gil-2 antigens with a molecular weight approximately 42 kDa, 42 and 45 kDa, 36 kDa, 40 kDa, and 40 kDa, respectively. These results indicate that human pulp cells possess the cellular machinery to respond to sensory neuropeptides when they are released from the peptidergic nerve fibers. On this basis, the relationships of postdevelopmental, age-dependent, and pathophysiological disorders of G-proteins subunits in dental pulp could be studied.