Expression of osteogenic factors in FasL-deficient calvarial cells

During bone development, FasL acts not only through the traditional apoptotic mechanism regulating the amount of bone-resorbing osteoclasts, but there is also growing evidence about its effect on cell differentiation. Expression of osteoblastic factors was followed in non differentiated and differentiating primary calvarial cells obtained from FasL-deficient (gld) mice. The gld cells showed decreased expression of the key osteoblastic molecules osteocalcin (Ocn), osteopontin (Opn), and alkaline phosphatase (Alpl) in both groups. Notably, receptor activator of nuclear factor kappa-B ligand (Rankl) was unchanged in non-differentiated gld vs. wild type (wt) cells but decreased in differentiating gld cells. Osteoprotegerin (Opg) in the gld samples was increased in both groups. Opg vs. Rankl expression levels favored Opg in the case of non-differentiated cells but Rankl in differentiating ones. These results expand information on the involvement of FasL in non-apoptotic cell pathways related to osteoblastogenesis and consequently also osteoclastogenesis and pathologies such as osteoporosis.

Tempol Reverses the Negative Effects of Morphine on Arterial Blood-Gas Chemistry and Tissue Oxygen Saturation in Freely-Moving Rats

We have reported that pretreatment with the clinically approved superoxide dismutase mimetic, Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), blunts the cardiorespiratory depressant responses elicited by a subsequent injection of fentanyl, in halothane-anesthetized rats. The objective of the present study was to determine whether Tempol is able to reverse the effects of morphine on arterial blood-gas (ABG) chemistry in freely-moving Sprague Dawley rats. The intravenous injection of morphine (10 mg/kg) elicited substantial decreases in pH, pO₂ and sO₂ that were accompanied by substantial increases in pCO₂ and Alveolar-arterial gradient, which results in diminished gas-exchange within the lungs. Intravenous injection of a 60 mg/kg dose of Tempol 15 min after the injection of morphine caused minor improvements in pO₂ and pCO₂ but not in other ABG parameters. In contrast, the 100 mg/kg dose of Tempol caused an immediate and sustained reversal of the negative effects of morphine on arterial blood pH, pCO₂, pO₂, sO₂ and Alveolar-arterial gradient. In other rats, we used pulse oximetry to determine that the 100 mg/kg dose of Tempol, but not the 60 mg/kg dose elicited a rapid and sustained reversal of the negative effects of morphine (10 mg/kg, IV) on tissue O₂ saturation (SpO₂). The injection of morphine caused a relatively minor fall in mean arterial blood pressure that was somewhat exacerbated by Tempol. These findings demonstrate that Tempol can reverse the negative effects of morphine on ABG chemistry in freely-moving rats paving the way of structure-activity and mechanisms of action studies with the host of Tempol analogues that are commercially available.

Systemic Administration of Tempol Attenuates the Cardiorespiratory Depressant Effects of Fentanyl

Fentanyl is a high-potency opioid receptor agonist that elicits profound analgesia and suppression of breathing in humans and animals. To date, there is limited evidence as to whether changes in oxidant stress are important factors in any of the actions of acutely administered fentanyl. This study determined whether the clinically approved superoxide dismutase mimetic, Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), or a potent antioxidant, N-acetyl-L-cysteine methyl ester (L-NACme), modify the cardiorespiratory and analgesic actions of fentanyl. We examined whether the prior systemic injection of Tempol or L-NACme affects the cardiorespiratory and/or analgesic responses elicited by the subsequent injection of fentanyl in isoflurane-anesthetized and/or freely moving male Sprague-Dawley rats. Bolus injections of Tempol (25, 50 or 100 mg/kg, IV) elicited minor increases in frequency of breathing, tidal volume and minute ventilation. The ventilatory-depressant effects of fentanyl (5 μg/kg, IV) given 15 min later were dose-dependently inhibited by prior injections of Tempol. Tempol elicited dose-dependent and transient hypotension that had (except for the highest dose) resolved when fentanyl was injected. The hypotensive responses elicited by fentanyl were markedly blunted after Tempol pretreatment. The analgesic actions of fentanyl (25 μg/kg, IV) were not affected by Tempol (100 mg/kg, IV). L-NACme did not modify any of the effects of fentanyl. We conclude that prior administration of Tempol attenuates the cardiorespiratory actions of fentanyl without affecting the analgesic effects of this potent opioid. As such, Tempol may not directly affect opioid-receptors that elicit the effects of fentanyl. Whether, the effects of Tempol are solely due to alterations in oxidative stress is in doubt since the powerful antioxidant, L-NACme, did not affect fentanyl-induced suppression of breathing.

Successful treatment of trichothiodystrophy with dupilumab

Click here for the corresponding questions to this CME article.

New Caledonian crows plan for specific future tool use

The ability to plan for future events is one of the defining features of human intelligence. Whether non-human animals can plan for specific future situations remains contentious: despite a sustained research effort over the last two decades, there is still no consensus on this question. Here, we show that New Caledonian crows can use tools to plan for specific future events. Crows learned a temporal sequence where they were (a) shown a baited apparatus, (b) 5 min later given a choice of five objects and (c) 10 min later given access to the apparatus. At test, these crows were presented with one of two tool-apparatus combinations. For each combination, the crows chose the right tool for the right future task, while ignoring previously useful tools and a low-value food item. This study establishes that planning for specific future tool use can evolve via convergent evolution, given that corvids and humans shared a common ancestor over 300 million years ago, and offers a route to mapping the planning capacities of animals.

0328 The Associations Between Self-Reported Symptoms of Sleep Disorders, Objective Sleep Patterns and Affect in Adolescence

Introduction

Developmental changes in adolescence make adolescents prone to experiencing negative mood and increased emotional lability. Experimental studies employing sleep restriction paradigms have shown that decreased sleep increased negative affect, but a gap exists regarding the association between sleep disorders and negative affect in adolescence. The objective of this study was to examine this association. It was hypothesized that higher levels of reported symptoms of sleep disorders would be associated with lower positive affect and higher negative affect in adolescents.

Methods

Participants: 101 adolescents (65 females) aged between 13 and 18 years old (M=14.69, SD=1.16). Measures: Sleep Disorders Inventory for Students was used to measure symptoms of sleep disorders and sleep patterns were measured objectively using actigraphy. Positive and Negative Affect Schedule (PANAS) was used to measure positive and negative affect.

Results

Correlational analyses were conducted to assess the relationship between symptoms of sleep disorders, sleep patterns, and positive and negative affect. Higher levels of reported symptoms of sleep disorders were associated with later bedtimes (r= .26, p< .01), shorter sleep durations (r= -.20, p< .05), increased sleep onset latency (r= .21, p< .05), decreased sleep efficiency (r= -.23, p< .05), and less immobile minutes (r= -.23, p< .05) measured by actigraphy. Higher levels of reported symptoms of sleep disorders were associated with lower levels of positive affect (r= -.20, p< .05) and higher levels of negative affect (r= .39, p< .001)

Conclusion

Reported symptoms of sleep disorders were associated with overall poorer sleep patterns in adolescents as well as decreased positive affect and increased negative affect. Sleep specialists assisting adolescents with sleep disorders should inquire about mood regulation.

Support

Social Sciences and Humanities Research Council

0959 Associations Between Sleep and Academic Performance in Typically Developing Adolescent Girls

Introduction

Healthy sleep promotes cognitive functioning and is associated with better academic performance, whereas insufficient, poor, and inconsistent sleep schedules are associated with poor school performance. Several studies have identified gender differences in the timing, duration, and quality of sleep in adolescence, with adolescent girls having poorer sleep compared to adolescent boys, yet research shows that girls outperform boys academically. This could be because sleep might not affect all subjects similarly and previous studies regarding sleep and academic performance combined both genders. The goal of the present study was to determine which aspects of academic performance are specifically associated with short or poor sleep in typically developing adolescents girls.

Methods

80 adolescent girls aged 12-17 years participated in the study. Sleep was assessed in the home environment for five consecutive weeknights using actigraphy. Academic performance was assessed using report card grades.

Results

Hierarchical regression analyses adjusted for age, pubertal status, and socioeconomic status revealed that longer average sleep time was significantly associated with higher grades in mathematics. No significant associations were found between sleep variables and grades in other subjects.

Conclusion

Longer average weekday sleep duration is associated with better mathematics grades in typically developing adolescent girls.

Support

NSERC grant to Reut Gruber

0217 Adolescents’ Evening Preference is Associated with Specific Sleep Hygiene Behaviours

Introduction

Circadian tendencies are associated with individual differences in preferred timing of behaviour. Sleep hygiene encompasses a variety of habits that are necessary for healthy. Given the later bedtimes of individuals with evening circadian preferences, more time is spent being awake in the evening and this could be associated with increased or longer engagement in poor sleep hygiene. Specific sleep hygiene practices that are common in adolescents with high evening preferences may therefore be a target to improve sleep. However, the relationship between specific sleep hygiene behaviours and circadian preferences in adolescents has not been examined. The objective of this study was to examine the associations between circadian preference and specific domains of sleep hygiene behavior.

Methods

127 adolescents (86 female) between 13 and 18 years old (M = 14.83, SD = 1.20) participated in the study. Circadian preferences were measured by the Morningness-Eveningness subscale of the School Sleep Habits Survey. Sleep hygiene was measured using the Adolescent Sleep Hygiene Scale (ASHS).

Results

Higher eveningness scores were significantly negatively associated with the ASHS physiological, behavioural arousal, cognitive emotional arousal, sleep environment, sleep stability, daytime sleep, substances use factors (r = -.20, p = <.05, r = -.27, p = <.01, r = -.32, p = <.01, r = -.18, p = <.05, r = -.41, p = <.01, r = -.28, p = <.01, r = 0.20, p = <.05 respectively) and with total sleep hygiene score (r = -.45, p = <.01).

Conclusion

Higher eveningness preferences in adolescents is significantly associated with poorer sleep hygiene in all domains with the exception of bedtime routine. Behavioural arousal, cognitive emotional, and sleep stability domains show the strongest inverse correlations. These findings could be used to inform the development of tailored sleep health interventions for adolescents with strong evening tendencies

Support

Social Sciences and Humanities Research Council (SSHRC) support for Dr. Reut Gruber.

0918 Quebec Adolescents’ Insomnia Symptoms, Mental Health & Access to Sleep Care

Introduction

Our school boards are part of the Quebec Center Of Excellence For Mental Health, and are thus mandated to identify and then prevent/treat factors that could negatively affect the mental health of their students. As part of this mission, we conducted a study that aimed 1) to examine the prevalence of insomnia in typically developing students in Quebec and their associations with students’ mental health, and; 2) to assess student access to behavioral sleep interventions in Quebec.

Methods

145 (Age 15.53+1; 75 Girls, 70 Boys) typically developing students. Insomnia symptoms were measured using the Insomnia Severity Index. Sleep was measured by Actigraphy. The Youth Self Report was used to measure students mental health. Access to care was measured using a detailed questionnaire.

Results

The key findings were: 1) 45% of the students reported poor sleep quality, dysfunction during the day due to sleepiness, difficulty falling or staying asleep, and excessive daytime sleepiness. Total scores on self-reports sleep measures were positively significantly correlated with Actigraphy measures of sleep duration and quality and with each other; 2) Robust positive associations were found between insomnia and psychiatric symptoms after adjusting for common risk factors, including age, socioeconomic status, and gender; 3) None of the students had access to sleep care and 25% of them reported using over-the counter sleep aids with minimal success.

Conclusion

These findings are alarming because they show that: 1) insomnia symptoms are prevalent in Quebec students and are strongly associated with the symptomatology of mental distress in students who do not meet the diagnostic criteria of a psychological disorder, and; 2) these students do not have access to insomnia care. These findings suggest that treatment of insomnia could offer an incredible opportunity to protect and improve the sleep and the mental health of these students.

Support

Canadian Institute of Health Research grant to Reut Gruber

0408 Myths About Infant, Child, and Adolescent Sleep: Addressing False Beliefs That Hinder Sleep Health During These Crucial Developmental Stages

Introduction

Sleep is vital for healthy development from infancy through adolescence. Despite its importance, false beliefs that conflict with scientific evidence (myths) may be common among caregivers and impair sleep health during these crucial stages.

Methods

Researchers compiled a list of potential myth statements using internet searches of popular press and scientific literature. We utilized a Delphi process with experts (n=12) from the fields of pediatric, sleep, and circadian research and clinical practice. Selection and refinement of myths by sleep experts proceeded in three phases, including: focus groups (Phase 1); email-based feedback to edit, add, or remove myths (Phase 2); and closed-ended questionnaires (Phase 3) where experts rated myths on two dimensions: (1) falseness and (2) public health significance using 5-point Likert scale: 1 (“not at all”) to 5 (“extremely false/important”).

Results

Thirty-two sleep myths were identified across three developmental categories: infant (14 myths), child (6 myths), and adolescent (12 myths). Mean expert ratings illuminated the most pressing myths in each developmental category: infant sleep (“Sleep training causes psychological harm, including reduced parent-child attachment:” falseness =4.7, s.d.=0.7; public health significance=4.0, s.d.=1.1); child sleep (“Heavy, loud snoring for my child means he’s sleeping deeply:” falseness=4.8, s.d.=0.6; public health significance=4.7, s.d.=0.7), and teenager sleep (“Falling asleep in class means your teenager is lazy and not motivated:” falseness=4.8, s.d.=0.5; public health significance=4.3, s.d.=0.8).

Conclusion

The current study identified commonly-held myths about infant, child, and adolescent sleep that are not supported by (or worse, counter to) scientific evidence. If unchecked, these myths may hinder sleep at a critical developmental stage. Future research may include public health education to correct myths and promote healthy sleep among infants, children, and teenagers.

Support

5T32HL007901

Saliva proteomic patterns in patients with molar incisor hypomineralization

Molar incisor hypomineralization (MIH) is an endemic pediatric disease with an unclear pathogenesis. Considering that saliva controls enamel remineralization and that MIH is associated with higher saliva flow rate, we hypothesized that the protein composition of saliva is linked to disease. To test this, we enrolled 5 children aged 6-14 years with MIH showing at least one hypersensitive molar and 5 caries-free children without hypomineralization. Saliva samples were subjected to proteomic analysis followed by protein classification in to biological pathways. Among 618 salivary proteins identified with high confidence, 88 proteins were identified exclusively in MIH patients and 16 proteins in healthy controls only. Biological pathway analysis classified these 88 patient-only proteins to neutrophil-mediated adaptive immunity, the activation of the classical pathway of complement activation, extracellular matrix degradation, heme scavenging as well as glutathione -and drug metabolism. The 16 controls-only proteins were associated with adaptive immunity related to platelet degranulation and the lysosome. This report suggests that the proteaneous composition of saliva is affected in MIH patients, reflecting a catabolic environment which is linked to inflammation.

Management of congenital ichthyoses: European guidelines of care, part one

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016 and a consensus on the discussions. They summarize evidence and expert-based recommendations and are intended to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part one, covering topical therapies, systemic therapies, psychosocial management, communicating the diagnosis and genetic counselling.

Management of congenital ichthyoses: European guidelines of care, part two

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016, and a consensus on the discussions. These guidelines summarize evidence and expert-based recommendations and intend to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part two, covering the management of complications and the particularities of some forms of congenital ichthyosis.

Morphological alterations in two siblings with autosomal recessive congenital ichthyosis associated with CYP4F22 mutations

Autosomal recessive congenital ichthyosis (ARCI) caused by mutations in CYP4F22 is very rare. CyP4F22, a protein of the cytochrome-P450 family 4, encodes an epidermal ω-hydroxylase decisive in the formation of acylceramides, which is hypothesized to be crucial for skin-barrier function. We report a girl with consanguineous parents presenting as collodion baby with contractures of the great joints and palmoplantar hyperlinearity. In the course of the disease she developed fine scaling of the skin with erythroderma, the latter disappearing until the age of 6 months. Her sister showed a generalized fine-scaling phenotype, and, interestingly, was born without a collodion membrane. The analysis of all known candidate genes for ARCI in parallel with a next-generation sequencing approach using a newly designed dermatogenetics gene panel revealed a previously unknown homozygous splice-site mutation c.549+5G>C in CYP4F22 in both girls, confirming the diagnosis of ARCI. Ultrastructural analysis by transmission electron microscopy in both patients showed epidermal hyperplasia, orthohyperkeratosis with persistence of corneodesmosomes into the outer stratum corneum layers, fragmented and disorganized lamellar lipid bilayers, which could be ascribed to inhomogeneous lamellar body secretion, as well as lamellar body and lipid entombment in the corneocytes. These findings correlated with increased transepidermal water loss on the functional level. For the first time, we report a collodion baby phenotype and epidermal barrier impairment in CyP4F22-deficient epidermis at both the ultrastructural and functional level, and corroborate the importance of CyP4F22 for epidermal maturation and barrier function.

[Position paper on medication-related osteonecrosis of the jaw (MRONJ)]

It is now 12 years since the first article on medication-related osteonecrosis of the jaw (MRONJ) was reported in 2003. The recognition of MRONJ is still inconsistent between physicians and dentists but it is without doubt a severe disease with impairment of oral health-related quality of life. This position paper was developed by three Austrian societies for dentists, oral surgeons and osteologists involved in this topic. This update contains amendments on the incidence, pathophysiology, diagnosis, staging and treatment and provides recommendations for management based on a multidisciplinary international consensus. The MRONJ can be a medication-related side effect of treatment of malignant and benign bone diseases with bisphosphonates (Bp), bevacizumab and denosumab (Dmab) as antiresorptive therapy. The incidence of MRONJ is highest in the oncology patient population (range 1-15 %), where high doses of these medications are used at frequent intervals. In the osteoporosis patient population, the incidence of MRONJ is estimated to be 0.001-0.01 %, marginally higher than the incidence in the general population (< 0.001 %). Other risk factors for MRONJ include glucocorticoid use, maxillary or mandibular bone surgery, poor oral hygiene, chronic inflammation, diabetes mellitus, ill-fitting dentures as well as other drugs, including antiangiogenic agents. Prevention strategies for MRONJ include elimination or stabilization of oral disease prior to initiation of antiresorptive agents, as well as maintenance of good oral hygiene. In those patients at high risk for the development of MRONJ, including cancer patients receiving high-dose BP or Dmab therapy, consideration should be given to withholding antiresorptive therapy following extensive oral surgery until the surgical site heals with mature mucosal coverage. Management of MRONJ is based on the stage of the disease, extent of the lesions and the presence of contributing drug therapy and comorbidity. Conservative therapy includes topical antibiotic oral rinses and systemic antibiotic therapy. Early data have suggested enhanced osseous wound healing with teriparatide in those patients without contraindications for its use. The MRONJ related to denosumab may resolve more quickly with a drug holiday than MRONJ related to bisphosphonates. Localized surgical debridement is indicated in advanced nonresponsive disease and has proven successful. More invasive surgical techniques are becoming increasingly more important. Prevention is the key for the management of MRONJ. This requires a close teamwork for the treating physician and the dentist. It is necessary that this information is disseminated to other relevant health care professionals and organizations.

Dental Pulp Fibroblasts Contain Target Cells for Lysophosphatidic Acid

Lysophosphatidic acid (LPA) is a locally produced bioactive phospholipid which is involved in tissue repair. The objective of this study was to determine whether dental pulp tissue also responds to the phospholipid. Effects of LPA on proliferation, differentiation, and mitogen-activated protein kinase (MAPK) signaling of dental pulp fibroblasts (DPF) were examined in vitro. We report that DPF express LPA receptors LPA1, LPA2, and LPA3 and respond to the ligand with increased mitogenic activity. Involvement of extracellular signal-regulated kinase, p38 MAPK, and c-Jun NH2-terminal kinase in LPA signaling could be demonstrated by use of specific inhibitors and detection of the phosphorylation status of the kinases. An increased mitogenic activity paralleled a decreased number of alkaline-phosphatase-positive cells and expression levels of dentin sialophosphoprotein and osteocalcin. Together, these results suggest that dental pulp fibroblasts can respond to LPA, a process that may play a role in pulp tissue repair.

Screens and Sleep: Are Interactive Screen Activities Associated with Short and Inefficient Sleep?

BACKGROUND: Although sleep is essential for healthy development, school-aged children are not getting the recommended number of hours of sleep each night. There is evidence that screen-based activity use is associated with shorter sleep duration and poorer sleep quality in pediatric populations. Findings also suggest that using more interactive activities, such as video games, might be associated with shorter and less efficient sleep, when compared to more passive activities, such as watching television. Few studies have examined this connection in school-aged children and none have employed objective measurements of sleep.

OBJECTIVES: The aim of the present study was to assess the associations between devices that are different in their level of interactivity with quantity and quality of sleep. We hypothesized that more interactive screen activities will explain more of the variability in sleep efficiency and sleep duration compared to less interactive activities.

DESIGN/METHODS: Participants included 78 school-aged children (M=8.57, SD=1.81). Sleep was assessed objectively using actigraphy, a non-invasive device worn to examine sleep-wake patterns by measuring movement. Variables of interest included sleep duration and sleep efficiency. Time spent engaging in screen time activities was assessed via parental reports on the Children’s Leisure Activities Study Survey. Screen activities included time spent watching television/videos, playing video games, and using the computer.

RESULTS: Multiple linear regression analyses were performed to determine possible associations between screen activities and sleep variables. In the first analysis, longer time spent on computer use and playing video gameswas negatively associated with sleep duration (b= -0.04, p&lt;.01; b = -0.05, p&lt;.01, respectively) and the full model explained 24% of the variance. In a second analysis, using the computer was negatively associated with sleep efficiency (b = -0.01, p&lt;.05) and the full model explained 14% of the variance.

CONCLUSION: The current study found that interactive screen activities, including video games playing and computer use, but not watching television, were associated with significantly shorter sleep duration and poorer sleep efficiency. These findings support previous research in school-aged children that suggests video games and other interactive activities are associated with short and inefficient sleep.

Identification and Characterization of GAL-021 as a Novel Breathing Control Modulator

BACKGROUND

The authors describe the preclinical pharmacological properties of GAL-021, a novel peripheral chemoreceptor modulator.

METHODS

The ventilatory effects of GAL-021 were characterized using tracheal pneumotachometry (n = 4 to 6), plethysmography (n = 5 to 6), arterial blood gas analyses (n = 6 to 11), and nasal capnography (n = 3 to 4) in naive animals and those subjected to morphine-induced respiratory depression. Morphine analgesia in rats was evaluated by tail-flick test (n = 6). Carotid body involvement in GAL-021 ventilatory effects was assessed by comparing responses in intact and carotid sinus nerve-transected rats. Hemodynamic effects of GAL-021 were evaluated in urethane-anesthetized rats (n = 7). The pharmacological profile of GAL-021 in vitro was investigated using radioligand binding, enzyme inhibition, and cellular electrophysiology assays.

RESULTS

GAL-021 given intravenously stimulated ventilation and/or attenuated opiate-induced respiratory depression in rats, mice, and nonhuman primates, without decreasing morphine analgesia in rats. GAL-021 did not alter mean arterial pressure but produced a modest increase in heart rate. Ventilatory stimulation in rats was attenuated by carotid sinus nerve transection. GAL-021 inhibited KCa1.1 in GH3 cells, and the evoked ventilatory stimulation was attenuated in Slo1 mice lacking the pore-forming α-subunit of the KCa1.1 channel.

CONCLUSIONS

GAL-021 behaved as a breathing control modulator in rodents and nonhuman primates and diminished opioid-induced respiratory depression without compromising opioid analgesia. It acted predominantly at the carotid body, in part by inhibiting KCa1.1 channels. Its preclinical profile qualified the compound to enter clinical trials to assess effects on breathing control disorders such as drug (opioid)-induced respiratory depression and sleep apnea.

Differential inflammatory response of dental pulp explants and fibroblasts to saliva

AIM

To investigate the inflammatory response of dental pulp fibroblasts and the respective explants to whole saliva.

METHODOLOGY

Explants from human and porcine dental pulp tissue and isolated dental pulp fibroblasts were used to investigate the inflammatory response to sterile saliva. Cytokine and chemokine expression was assessed by RT-PCR. Western blot analysis and pharmacologic inhibitors were used to determine the involvement of signalling pathways.

RESULTS

Dental pulp explants of human and porcine origin exposed to human saliva exhibited no major changes of IL-6 and IL-8 mRNA expression (P > 0.05). In contrast, isolated porcine and human dental pulp fibroblasts, when stimulated with human saliva, exhibited a vastly increased expression of IL-6 and IL-8 mRNA (P < 0.05). In pulp fibroblasts, saliva also increased the expression of other cytokines and chemokines via activation of NFkappaB, ERK and p38 signalling. Notably, a significantly reduced inflammatory response was elicited when pulp fibroblasts were transiently exposed to saliva.

CONCLUSIONS

Saliva has a potential impact on inflammation of dental pulp fibroblasts in vitro but not when cells are embedded in the intrinsic extracellular matrix of the explant tissue.