Polymorphism in epigenetic regulating genes in relation to periodontitis, number of teeth, and levels of high-sensitivity C-reactive protein and glycated hemoglobin: The Tromsø Study 2015-2016

BACKGROUND

The aim of this study was to investigate the association between periodontitis and four single nucleotide polymorphisms (SNPs) in genes involved in epigenetic regulation of DNA, and between these same SNPs and tooth loss, high-sensitivity C-reactive protein (hs-CRP), and glycated hemoglobin (HbA1c) levels.

METHODS

We included participants with periodontal examination (n = 3633, aged: 40-93 years) from the Tromsø Study seventh survey (2015-2016), Norway. Periodontitis was defined according to the 2017 AAP/EFP classification system as no periodontitis, grades A, B, or C. Salivary DNA was extracted and genotyping was performed to investigate four SNPs (rs2288349, rs35474715, rs34023346, and rs10010325) in the sequence of the genes DNMT1, IDH2, TET1, and TET2. Association between SNPs and periodontitis was analyzed by logistic regression adjusted for age, sex, and smoking. Subgroup analyses on participants aged 40-49 years were performed.

RESULTS

In participants aged 40-49 years, homozygous carriage of minor A-allele of rs2288349 (DNMT1) was associated with decreased susceptibility to periodontitis (grade A: odds ratio [OR] 0.55; p = 0.014: grade B/C OR 0.48; p = 0.004). The minor A-allele of rs10010325 (TET2) was associated with increased susceptibility to periodontitis (grade A OR 1.69; p = 0.035: grade B/C OR 1.90; p = 0.014). In the entire sample, homozygous carriage of the G-allele of rs35474715 (IDH2) was associated with having ≤24 teeth (OR 1.31; p = 0.018). Homozygous carriage of the A-allele of TET2 was associated with hs-CRP≥3 mg/L (OR 1.37; p = 0.025) and HbA1c≥6.5% (OR 1.62; p = 0.028).

CONCLUSIONS

In this Norwegian population, there were associations between polymorphism in genes related to DNA methylation and periodontitis, tooth loss, low-grade inflammation, and hyperglycemia.

Decontamination of biofilm-contaminated implant surfaces: An in vitro evaluation

OBJECTIVES

The aim of the present study was to evaluate the cleaning efficacy of two mechanical and two chemical protocols in the decontamination of implant surfaces.

METHODS

In total, 123 commercially available implants were mounted in plastic models mimicking peri-implant circumferential intra-bony defects. A multispecies biofilm was grown on implant surfaces. Mechanical (air-polishing (AP), rotating titanium brush (TiB)) and chemical decontamination (alkaline electrolyzed water, N-acetyl-L-cysteine) protocols were used. Cleaning efficacy in terms of residual biofilm area, chemical surface properties, and bacterial counts were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and quantitative polymerase chain reaction.

RESULTS

Surface decontamination protocols including use of an AP device or a rotating TiB were superior in terms of biofilm removal and in reducing atomic% of Carbon on implant surfaces when compared to methods restricted to wiping with gauze. The use of chemical agents as adjuncts to the mechanical cleaning protocols provided no relevant overall benefit over saline. No treatment modality, however, resulted in complete biofilm removal.

CONCLUSION

Air-polishing and rotating TiB were more effective implant surface decontamination protocols than wiping with gauzes. Use of chemical agents did not improve cleaning efficacy.

Surface decontamination of explanted peri-implantitis-affected implants

AIM

The present study aimed at evaluating the effect of air-polishing (AP) and a combination of AP and alkaline electrolysed water (AEW) in surface decontamination of explanted peri-implantitis-affected implants.

MATERIALS AND METHODS

Twenty-five patients with 34 dental implants scheduled for explantation due to severe peri-implantitis were included. Following implant removal, the apical part of each implant was embedded in acrylic blocks. Implants were randomly allocated to surface decontamination using AP with or without AEW. Four implants were left untreated and used as negative controls. Specimens were analysed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Area of residual bacteria was the primary outcome.

RESULTS

SEM analysis revealed that both treatment protocols were effective in biofilm removal and only small proportions of target areas of the implants showed residual bacterial or mineralized deposits. Although differences between the treatment protocols were small, implant thread loci (top/flank/valley), zones of the implant (apical/middle/coronal), implant surface characteristics and gender influenced the results. In addition, EDS analysis showed that zones influenced the atomic% of carbon and calcium and that implant surface characteristics affected the atomic% of titanium.

CONCLUSIONS

AP, with or without AEW, is an effective method in removing biofilm from peri-implantitis-affected implants.

BMP Gene-Immobilization to Dental Implants Enhances Bone Regeneration

For individuals who have experienced tooth loss, dental implants are an important treatment option for oral reconstruction. For these patients, alveolar bone augmentation and acceleration of osseointegration optimize implant stability. Traditional oral surgery often requires invasive procedures, which can result in prolonged treatment time and associated morbidity. It has been previously shown that chemical vapor deposition (CVD) polymerization of functionalized [2.2]paracyclophanes can be used to anchor gene encoding vectors onto biomaterial surfaces and local delivery of a bone morphogenetic protein (BMP)-encoding vector can increase alveolar bone volume and density in vivo. This study is the first to combine the use of CVD technology and BMP gene delivery on titanium for the promotion of bone regeneration and bone to implant contact in vivo. BMP-7 tethered to titanium surface enhances osteoblast cell differentiation and alkaline phosphatase activity in vitro and increases alveolar bone regeneration and % bone to implant contact similar to using high doses of exogenously applied BMP-7 in vivo. The use of this innovative gene delivery strategy on implant surfaces offers an alternative treatment option for targeted alveolar bone reconstruction.

Influence of epigenetics on periodontitis and peri-implantitis pathogenesis

Periodontitis is a disease characterized by tooth-associated microbial biofilms that drive chronic inflammation and destruction of periodontal-supporting tissues. In some individuals, disease progression can lead to tooth loss. A similar condition can occur around dental implants in the form of peri-implantitis. The immune response to bacterial challenges is not only influenced by genetic factors, but also by environmental factors. Epigenetics involves the study of gene function independent of changes to the DNA sequence and its associated proteins, and represents a critical link between genetic and environmental factors. Epigenetic modifications have been shown to contribute to the progression of several diseases, including chronic inflammatory diseases like periodontitis and peri-implantitis. This review aims to present the latest findings on epigenetic influences on periodontitis and to discuss potential mechanisms that may influence peri-implantitis, given the paucity of information currently available.

Cellular expression of epigenetic markers and oxidative stress in periodontitis lesions of smokers and non-smokers

Objective

To evaluate differences in the cellular expression of epigenetic markers and oxidative stress in periodontitis lesions between current smokers and non‐smokers.

Background

Tobacco smoking is recognized as one of the major risk factors for periodontitis. However, the mechanisms by which smoking affects the progression of the disease remain to be determined.

Methods

Twenty‐five current smokers and 21 non‐smokers with generalized severe periodontitis were included. From each patient, one soft tissue biopsy from a periodontitis site was harvested and prepared for histological analysis. The infiltrated connective tissue (ICT) was selected as the region of interest to assess the cellular expression of epigenetic markers and reactive oxygen/nitrogen species (RONS) by immunohistochemistry.

Results

Although the ICT of smokers and non‐smokers did not differ in size or in the expression of markers for DNA damage or oxidative stress, current smokers presented with significantly lower area proportions and densities of cells positive for the epigenetic markers DNMT1 and AcH3. In addition, periodontitis lesions in current smokers presented with a diminished antimicrobial activity, as indicated by significantly lower densities and area proportions of NOX2‐ and iNOS‐positive cells.

Conclusions

Components of the host response and epigenetic mechanisms in periodontitis lesions in smokers are downregulated as opposed to lesions of non‐smokers.

Global DNA Methylation in Dental Implant Failure Due to Peri-Implantitis: An Exploratory Clinical Pilot Study

Background: Peri-implantitis (PIT) is highly prevalent in patients with dental implants and is a challenging condition to treat due to the limited outcomes reported for non-surgical and surgical therapies. Therefore, epigenetic therapeutics might be of key importance to treat PIT. However, developing epigenetic therapeutics is based on understanding the relationship between epigenetics and disease. To date, there is still scarce knowledge about the relationship between epigenetic modifications and PIT, which warrants further investigations. Aim: The purpose of this study was to evaluate the level of global DNA methylation associated with implant failure (IF) due to PIT compared to periodontally healthy (PH) patients. Material and Methods: A total of 20 participants were initially enrolled in this pilot, exploratory, single-blinded, cross-sectional clinical human study in two groups: 10 in the PH group and 10 in the IF group. In the participants who have completed the study, gingival tissue and bone samples were harvested from each participant and were used to perform global DNA methylation analysis. The percentage of global DNA methylation (5-mC%) was compared (1) between groups (PH and IF); (2) between the subgroups of gingival tissue and bone separately; (3) in the whole sample, comparing gingival tissue and bone; (4) within groups, comparing gingival tissue and bone. Demographic, periodontal, and peri-implant measurements as well as periodontal staging, were also recorded. All statistical comparisons were made at the 0.05 significance level. Results: Out of the initially enrolled 20 patients, only 19 completed the study and, thus, were included in the final analysis; 10 patients in the PH group and 9 patients in the IF group, contributing to a total of 38 samples. One patient from the IF group was excluded from the study due to systemic disease. The mean implant survival time was 10.8 years (2.17–15.25 years). Intergroup comparison, stratified by group, indicated a similar 5-mC% between the PH and IF groups in both gingival tissue and bone (p = 0.599), only in bone (p = 0.414), and only in gingival tissue (p = 0.744). Intragroup comparison, stratified by the type of sample, indicated a significantly higher 5-mC% in gingival tissue samples compared to bone in both the PH and IF groups (p = 0.001), in the PH group (p = 0.019), and in the IF group (p = 0.009). Conclusions: Within the limitations of this study, higher global DNA methylation levels were found in gingival tissue samples compared to bone, regardless of the study groups. However, similar global DNA methylation levels were observed overall between the IF and PH groups. Yet, differences in the global DNA methylation levels between gingival tissues and bone, regardless of the study group, could reflect a different epigenetic response between various tissues within the same microenvironment. Further studies are necessary to elucidate the present findings and to evaluate the role of epigenetic modifications in IF due to PIT.

Understanding the role of endotoxin tolerance in chronic inflammatory conditions and periodontal disease

OBJECTIVE

This review aims to present the current understanding of endotoxin tolerance (ET) in chronic inflammatory diseases and explores the potential connection with periodontitis.

SUMMARY

Subsequent exposure to lipopolysaccharides (LPS) triggers ET, a phenomenon regulated by different mechanisms and pathways, including toll-like receptors (TLRs), nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), apoptosis of immune cells, epigenetics, and microRNAs (miRNAs). These mechanisms interconnect ET with chronic inflammatory diseases that include periodontitis. While the direct correlation between ET and periodontal destruction has not been fully elucidated, emerging reports point towards the potential tolerization of human periodontal ligament cells (hPDLCs) and gingival tissues with a significant reduction of TLR levels.

CONCLUSIONS

There is a potential link between ET and periodontal diseases. Future studies should explore the crucial role of ET in the pathogenesis of periodontal diseases as evidence of a tolerized oral mucosa may represent an intrinsic mechanism capable of regulating the oral immune response. A clear understanding of this host immune regulatory mechanism might lead to effective and more predictable therapeutic strategies to treat chronic inflammatory diseases and periodontitis. This article is protected by copyright. All rights reserved.

Mechanical removal of biofilm on titanium discs: An in vitro study

The objective of this in vitro study was to evaluate surface cleanness and cytocompatibility following mechanical instrumentation of biofilm-contaminated titanium surfaces. Titanium discs (non-modified [Ti(s)] and shot-blasted surfaces [Ti(r)]) contaminated with Streptococcus gordonii were instrumented using four different techniques: (i) gauze soaked in saline (GS), (ii) ultra-sonic device (US), (iii) rotating nickel-titanium brush (TiB), or (iv) air-polishing device (AP). Non-contaminated, untreated titanium disks were used as controls (C). Residual deposits and cytocompatibility for osteoblast-like cells were evaluated using scanning electron microscopy, immunofluorescence, and reverse transcriptase polymerase chain reaction. While the number of residual bacteria on Ti(s) discs was close to 0 in all treatment groups, significantly higher mean numbers of residual bacteria were observed on Ti(r) discs for GS (152.7 ± 75.7) and TiB (33.5 ± 22.2) than for US (0) and AP (0). Instrumentation with US resulted in deposition of foreign material (mean area% of foreign material: 3.0 ± 3.6% and 10.8 ± 9.6% for Ti(s) and Ti(r) discs, respectively). AP was the most effective decontamination procedure in reducing bacteria without depositing residual foreign material on Ti(r) discs. TiB and AP were superior methods in restoring cytocompatibility, although no method of mechanical decontamination resulted in pristine levels of cytocompatibility.

Teaching for Student and Societal Wellbeing in HPE: Nine Pedagogies for Social Justice

We currently find ourselves living in precarious times, with old and new social inequities on the rise due to the challenges associated with an unprecedented rise of global migration and neoliberalism, amplified in our post COVID-19 world. Research has demonstrated that there is a high correlation between inequality at the societal level and the overall health and wellbeing of individuals within those societies. We believe that school health and physical education (HPE) has a significant role to play in addressing and acting on social inequities that impact on the wellbeing of both students and society as a whole. Based on the findings of an international research project called EDUHEALTH which explored pedagogies for social justice in school health and physical education (HPE) across Sweden, Norway and New Zealand, this paper aims to highlight the addressing of (in)equality and student wellbeing through HPE practice. In particular, the paper presents nine different but complementary pedagogies for social justice that we believe can improve individual, collective, and societal wellbeing. We conclude by proposing that, if adopted across a whole school curriculum, these nine pedagogies for social justice could form the basis of a holistic school-wide community approach aimed at improving both student and societal wellbeing.

Cellular expression of DNA damage/repair and reactive oxygen/nitrogen species in human periodontitis and peri-implantitis lesions

AIM OF THE STUDY

To evaluate differences in the cellular expression of DNA damage/repair and reactive oxygen/nitrogen species between human periodontitis and peri-implantitis lesions.

MATERIAL AND METHODS

40 patients presenting with generalized severe periodontitis and 40 patients with severe peri-implantitis were included. Soft tissue biopsies were collected from diseased sites in conjunction with surgical therapy and prepared for histological analysis. Four regions of interest were identified: the pocket epithelium (PE), the infiltrated connective tissue (ICT), which was divided into one inner area facing the PE (ICT-1) and one outer area (ICT-2). A non-infiltrated connective tissue area (NCT) lateral of the ICT was also selected.

RESULTS

It was demonstrated that the ICT of peri-implantitis specimens was considerably larger and contained significantly larger area proportions and densities of CD68-, MPO- and iNOS-positive cells than that of periodontitis samples. Cellular densities were overall higher in the inner ICT zone lateral of the PE (ICT-1) than in the outer ICT compartment (ICT-2). While the NCT area lateral of the ICT comprised significantly larger proportions and densities of y-H2AX-, iNOS-, NOX2-, MPO- and PAD4/MPO-positive cells in peri-implantitis than in periodontitis sites, a reverse difference was noted for the area proportion and density of 8-OHdG-positive cells in the PE.

CONCLUSIONS

It is suggested that peri-implantitis lesions are associated with an enhanced and upregulated host response and contain larger numbers of neutrophils, macrophages and iNOS-positive cells than periodontitis lesions.

Late cardiac interventions in adults with congenital ventricular septal defects

Introduction

Ventricular septal defect (VSD) is one of the most common congenital heart lesions. Shunts with hemodynamic significance are usually closed early in life whereas small shunts are left without intervention. The need for late cardiac interventions in these populations is essentially unknown. The aim was to study the late cardiac interventions in adults with VSD.

Methods

The national register on congenital heart disease was searched for patients with VSD with or without associated simple cardiac defects but without complex lesions. For these patients, the last 10 years (over the age of 18) in the national patient register was searched for cardiac interventions.

Results

774 patients (mean age 39.0±14.7 years, women =50.6%), 224 (28.9%) with previous closure of VSD, were identified. The total observed time was 6920 patient years. There were 43 interventions in 41 patients (5.3%) of whom 12 had a previous closure of VSD. Twelve patients had isolated closure of VSD, 18 closure of VSD together with other cardiac surgery (one of these had repeated cardiac surgery) and 8 had only other cardiac surgery. In 4 cases, a pacemaker was implanted, of whom one together with cardiac surgery.

Conclusion

The need for cardiac interventions is relatively common in adults with a VSD, also in those without previous closure of their shunt. Our data suggests that most patients with a VSD, closed or not, should be offered periodic follow-up as approximately one out of 20 patients may encounter a complication within 10 years.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The Swedish Heart-Lung Foundation

Immunohistological composition of peri-implantitis affected tissue around ceramic implants-A pilot study

BACKGROUND

Aim of the pilot study was the histologic classification of the inflamed peri-implant soft tissue around ceramic implants (CI) in comparison with titanium implants (TI).

METHODS

Peri-implant tissue were retrieved from 15 patients (aged 34 to 88 years, seven males/eight females) with severe peri-implantitis (eight CI, seven TI). The peri-implant soft tissue samples were retrieved from the sites during scheduled removal of the implant and prepared for immunohistochemical analysis. Monoclonal antibodies (targeting CD3, CD20, CD138, and CD68) were used to identify T- and B-cells, plasma cells and macrophages. Quantitative assessment was performed by one histologically trained investigator. Linear mixed regression models were used.

RESULTS

A similar numerical distribution of the cell population was found in peri-implantitis around CI compared with TI. CD3 (TI, 17% to 85% versus CI, 20% to 70% of total cell number) and CD138 (TI, 1% to 73% versus CI, 12% to 69% of total cell number) were predominantly expressed. Notably, patient-individual differences of numerical cell distribution were detected. Co-localization of B- and T-lymphocytes was observed.

CONCLUSIONS

Peri-implantitis around CI in comparison with TI seems to have a similar histological appearance. Differences in cellular composition of peri-implantitis lesions might also depend on the patient's specific immune status and not only on the material used.

The Role of DNA Methylation and Histone Modification in Periodontal Disease: A Systematic Review

Despite a number of reports in the literature on the role of epigenetic mechanisms in periodontal disease, a thorough assessment of the published studies is warranted to better comprehend the evidence on the relationship between epigenetic changes and periodontal disease and its treatment. Therefore, the aim of this systematic review is to identify and synthesize the evidence for an association between DNA methylation/histone modification and periodontal disease and its treatment in human adults. A systematic search was independently conducted to identify articles meeting the inclusion criteria. DNA methylation and histone modifications associated with periodontal diseases, gene expression, epigenetic changes after periodontal therapy, and the association between epigenetics and clinical parameters were evaluated. Sixteen studies were identified. All included studies examined DNA modifications in relation to periodontitis, and none of the studies examined histone modifications. Substantial variation regarding the reporting of sample sizes and patient characteristics, statistical analyses, and methodology, was found. There was some evidence, albeit inconsistent, for an association between DNA methylation and periodontal disease. IL6, IL6R, IFNG, PTGS2, SOCS1, and TNF were identified as candidate genes that have been assessed for DNA methylation in periodontitis. While several included studies found associations between methylation levels and periodontal disease risk, there is insufficient evidence to support or refute an association between DNA methylation and periodontal disease/therapy in human adults. Further research must be conducted to identify reproducible epigenetic markers and determine the extent to which DNA methylation can be applied as a clinical biomarker.

Epigenetic changes of osteoblasts in response to titanium surface characteristics

We aimed to investigate the influence of titanium surface characteristics on epigenetic mechanisms and DNA damage/repair pathways. Osteoblast-like cells (MG63) were incubated on glass, smooth titanium, and minimally rough titanium discs, respectively, for 0, 1, 6, and 24 hr. The presence of double-stranded DNA damage (γH2AX), DNA repair (Chk2), and epigenetic markers (AcH3 & DNMT1) were investigated using immunofluorescence. There were no Chk2-positive cells on the minimally rough titanium surfaces at all-time points, in comparison to glass and smooth titanium. Total γH2AX-positive cells on minimally rough titanium gradually decreased as incubation time increased, on the contrary to smooth titanium. Minimally rough titanium surfaces induced cytoplasmic staining of DNMT1 up to 99% at 24 hr. For epigenetic markers related to the DNA damage/repair pathway, minimally rough titanium surfaces showed the lower percentage of AcH3-positive cells compared to glass and smooth titanium surface. The findings in the current study show that titanium surface characteristics indeed influence DNA damage and the DNA repair pathway, including epigenetic factors.

Maresin 1 Promotes Wound Healing and Socket Bone Regeneration for Alveolar Ridge Preservation

Tooth extraction results in alveolar bone resorption and is accompanied by postoperative swelling and pain. Maresin 1 (MaR1) is a proresolving lipid mediator produced by macrophages during the resolution phase of inflammation, bridging healing and tissue regeneration. The aim of this study was to examine the effects of MaR1 on tooth extraction socket wound healing in a preclinical rat model. The maxillary right first molars of Sprague-Dawley rats were extracted, and gelatin scaffolds were placed into the sockets with or without MaR1. Topical application was also given twice a week until complete socket wound closure up to 14 d. Immediate postoperative pain was assessed by 3 scores. Histology and microcomputed tomography were used to assess socket bone fill and alveolar ridge dimensional changes at selected dates. The assessments of coded specimens were performed by masked, calibrated examiners. Local application of MaR1 potently accelerated extraction socket healing. Macroscopic and histologic analysis revealed a reduced soft tissue wound opening and more rapid re-epithelialization with MaR1 delivery versus vehicle on socket healing. Under micro-computed tomography analysis, MaR1 (especially at 0.05 μg/μL) stimulated greater socket bone fill at day 10 as compared with the vehicle-treated animals, resulting in less buccal plate resorption and a wider alveolar ridge by day 21. Interestingly, an increased ratio of CD206⁺:CD68⁺ macrophages was identified in the sockets with MaR1 application under immunohistochemistry and immunofluorescence analysis. As compared with the vehicle therapy, local delivery of MaR1 reduced immediate postoperative surrogate pain score panels. In summary, MaR1 accelerated extraction wound healing, promoted socket bone fill, preserved alveolar ridge bone, and reduced postoperative pain in vivo with a rodent preclinical model. Local administration of MaR1 offers clinical potential to accelerate extraction socket wound healing for more predictable dental implant reconstruction.

Gene Delivery Therapeutics in the Treatment of Periodontitis and Peri-Implantitis: A State of the Art Review

BACKGROUND

Periodontal disease is a chronic inflammatory condition that affects supporting tissues around teeth, resulting in periodontal tissue breakdown. If left untreated, periodontal disease could have serious consequences; this condition is in fact considered as the primary cause of tooth loss. Being highly prevalent among adults, periodontal disease treatment is receiving increased attention from researchers and clinicians. When this condition occurs around dental implants, the disease is termed peri-implantitis. Periodontal regeneration aims at restoring the destroyed attachment apparatus, in order to improve tooth stability and thus reduce disease progression and subsequent periodontal tissue breakdown. Although many biomaterials have been developed to promote periodontal regeneration, they still have their own set of disadvantages. As a result, regenerative medicine has been employed in the periodontal field, not only to overcome the drawbacks of the conventional biomaterials but also to ensure more predictable regenerative outcomes with minimal complications. Regenerative medicine is considered a part of the research field called tissue engineering/regenerative medicine (TE/RM), a translational field combining cell therapy, biomaterial, biomedical engineering and genetics all with the aim to replace and restore tissues or organs to their normal function using in vitro models for in vivo regeneration. In a tissue, cells are responding to different micro-environmental cues and signaling molecules, these biological factors influence cell differentiation, migration and cell responses. A central part of TE/RM therapy is introducing drugs, genetic materials or proteins to induce specific cellular responses in the cells at the site of tissue repair in order to enhance and improve tissue regeneration. In this review, we present the state of art of gene therapy in the applications of periodontal tissue and peri-implant regeneration.

PURPOSE

We aim herein to review the currently available methods for gene therapy, which include the utilization of viral/non-viral vectors and how they might serve as therapeutic potentials in regenerative medicine for periodontal and peri-implant tissues.

Aerobic capacity in adolescence is associated with time to intervention in adult men with atrial septal defects

BACKGROUND

Atrial septal defect (ASD) is a congenital heart lesion that often remains undiagnosed until adulthood. The reasons for this may be multifactorial. It is, however, known that closure of a hemodynamically significant ASD improves exercise capacity. This study aimed to explore whether the aerobic capacity in late adolescence is associated with time to diagnosis and intervention in adult men with late diagnosis of an atrial shunt.

METHODS

The Swedish Military Conscription Service Register contains data on exercise tests performed in late adolescence. By linking these data with the National Patient Register, 254 men with a later intervention for an ASD were identified.

RESULTS

Interventions were performed at a mean of 26.5 ± 7.9 years after the initial exercise tests. The mean absolute workload among those with a later diagnosed ASD was similar to those without a later diagnosed ASD (274 ± 51 W vs. 276 ± 52 W, p = 0.49). Men with a higher exercise capacity (≥1 SD) had their intervention earlier (21.9 ± 8.6 years vs. 27.5 ± 7.4 years, p < 0.001).

CONCLUSIONS

The aerobic exercise capacity was similar in adolescent men with later interventions for ASD compared to the reference population. Furthermore, those with high exercise capacity appeared to be diagnosed earlier. Thus, low exercise capacity may not be a feature of ASD during adolescence, but rather develop later in life as a natural progression of the disease.

The Immunomodulatory Properties of 2-Hydroxyethyl Methacrylate are Mediated by the NLRP3 Inflammasome

PURPOSE

The methacrylate monomer 2-hydroxyethyl methacrylate (HEMA), commonly used in dentistry, has multiple effects on the immune system. This study examined whether HEMA affects the immune system by inducing formation of the NLRP3 inflammasome.

MATERIALS AND METHODS

Human peripheral blood mononuclear cells (PBMCs) and the human monocyte cell line THP1 were cultured with or without 1000 μM HEMA. To block NLRP3 inflammasome activation, 130 mM KCl was also added to some of the cultures. For the in vivo studies, two different experimental setups were used. In the first experimental setup, mice were injected subcutaneously at the base of the tail with 20 μmol HEMA with or without 100 mM KCl. After 3 weeks, the animals were given an identical booster injection. Two weeks after the last injection, the mice were sacrificed and splenectomized. In the second experimental setup, HEMA (20 μmol), with or without 100 mM KCl, was injected subcutaneously into the tails of BALB/c mice. The mice were given two similar injections at 3-week intervals to allow evaluation of the local inflammation induced by HEMA. After the last inoculation, the injection site was examined daily for 4 days, after which the mice were sacrificed.

RESULTS

Cultures of PBMCs and THP1 cells exposed to HEMA in vitro produced more IL-1ß and IL-18 than did control cells. Increased extracellular concentration of KCl inhibited the secretion of IL-1ß. HEMA exposure did not induce cytokine production in variants of the THP1 cell line unable to form the NLRP3 inflammasome. For the first experimental setup, the level of unstimulated basic splenocyte proliferation in vitro was significantly higher in cultures from mice exposed in vivo to HEMA only than in cultures from mice injected with HEMA plus KCl. In the second experimental setup of the in vivo studies, the HEMA-treated mice developed more pronounced inflammation at the site of injection compared to the group of mice given HEMA plus KCl.

CONCLUSION

HEMA affects the immune system by inducing formation of the NLRP3 inflammasome.

Interleukin-17-producing T cells and interleukin-17 mRNA expression in periodontitis and long-standing gingivitis lesions

BACKGROUND

T helper17 cells (Th17) are key targets in the evaluation of differences between "destructive" and "non-destructive" periodontal lesions. The aim of the present study was to analyze the density of interleukin-17 (IL-17) producing T cells and IL-17 mRNA expression in lesions representing severe periodontitis and longstanding gingivitis.

METHODS

Two groups of patients were recruited. The gingivitis group consisted of 28 patients, 41-70 years old, with evident signs of gingival inflammation but no attachment loss. The periodontitis group consisted of 36 patients, 33-67 years of age. A gingival biopsy was obtained from one selected diseased site from each patient and prepared for immunohistochemical and reverse transcription, quantitative polymerase chain reaction (RT-qPCR) analysis.

RESULTS

Although the density of CD3 positive cells (T cells) did not differ between the two types of lesions, the total number and density of cells positive for CD3+CD161 (IL-17-producing T-cells) were larger in periodontitis than in long-standing gingivitis lesions. About 30% of CD3-cells in periodontitis lesions were also positive for CD161. The corresponding figure for gingivitis samples was 15%. Analysis of covariance (ANCOVA) analysis revealed that differences between periodontitis and gingivitis samples remained after adjusting for smoking, age, and gender. In addition, males had larger proportions of IL-17 producing T cells than females in both groups. The IL-17 mRNA expression was higher in periodontitis than in gingivitis samples.

CONCLUSION

It is suggested that IL-17 producing T cells represent a significant feature in the detection of differences between destructive and non-destructive lesions.

Adults with congenital heart disease overestimate their physical activity level

Background

Physical activity reduces the risk of acquired cardiovascular disease, which is of great importance in patients with congenital heart disease (CHD). There are diverging data whether physical activity level (PAL) differs between patients with CHD and controls. Furthermore, it is unknown if PAL can be reliably assessed in patients with CHD using self-reported instruments.

Methods

Seventy-five patients with CHD (mean age 37.5 ± 15.5 years, women n = 29 [38.7%]) and 42 age and sex matched controls completed the International Physical Activity Questionnaire (IPAQ) and carried the activity monitor Actiheart over 4 days. Time spent at ≥3 METS ≥21.4 min/day, i.e. reaching the WHO recommendation for PAL to promote health, was used as the outcome measure. Data on PAL obtained from IPAQ were compared with Actiheart.

Results

The proportion of individuals reaching target PAL according to IPAQ was similar in patients with CHD and controls (70.7%vs.76.2%, p = 0.52) as well as between patients with simple and complex lesions. There was an overall difference between IPAQ and Actiheart in detecting recommended PAL (72.6%vs.51.3%, p < 0.001). In a subgroup analysis, this difference was also detected in patients but was borderline for controls. The negative predictive value for IPAQ in detecting insufficient PAL was higher in patients than in controls (73%vs.40%).

Conclusions

The proportion of persons reaching sufficient PAL to promote health was similar in patients and controls. The self-reported instrument overestimated PAL in relation to objective measurements. However, with a high negative predictive value, IPAQ is a potentially useful tool for detecting patients with insufficient PAL.

Micropatterned Scaffolds with Immobilized Growth Factor Genes Regenerate Bone and Periodontal Ligament-Like Tissues

Periodontal disease destroys supporting structures of teeth. However, tissue engineering strategies offer potential to enhance regeneration. Here, the strategies of patterned topography, spatiotemporally controlled growth factor gene delivery, and cell-based therapy to repair bone-periodontal ligament (PDL) interfaces are combined. Micropatterned scaffolds are fabricated for the ligament regions using polycaprolactone (PCL)/polylactic-co-glycolic acid and combined with amorphous PCL scaffolds for the bone region. Scaffolds are modified using chemical vapor deposition, followed by spatially controlled immobilization of vectors encoding either platelet-derived growth factor-BB or bone morphogenetic protein-7, respectively. The scaffolds are seeded with human cells and delivered to large alveolar bone defects in athymic rats. The effects of dual and single gene delivery with and without micropatterning are assessed after 3, 6, and 9 weeks. Gene delivery results in greater bone formation at three weeks. Micropatterning results in regenerated ligamentous tissues similar to native PDL. The combination results in more mature expression of collagen III and periostin, and with elastic moduli of regenerated tissues that are statistically indistinguishable from those of native tissue, while controls are less stiff than native tissues. Thus, controlled scaffold microtopography combined with localized growth factor gene delivery improves the regeneration of periodontal bone-PDL interfaces.

Study on site-specific expression of bone formation and resorption factors in human dental follicles

We sought to investigate site‐specific expression of bone‐regulatory factors expressed by human dental follicles and to compare the stimulated expression of tumour necrosis factor (ligand) superfamily, member 11/tumour necrosis factor receptor superfamily, member 11b (RANKL/OPG) in human dental follicle cells (HDFCs) from different patients. Analysis of bone‐regulatory markers in follicles from 12 different study participants was performed using RT‐qPCR and immunofluorescence; apical and coronal segments from each dental follicle were processed independently. Four additional dental follicles were used for cell cultures; HDFCs were precultured in osteogenic medium to initiate differentiation and thereafter cultured with 10⁻⁶ M forskolin (FSK) to activate the protein kinase cAMP (PKA/cAMP) signalling pathway and induce RANKL/OPG expression. We demonstrate that RANKL expression is significantly higher in the coronal part of follicles than in the apical part. High levels of collagen type 1 (COL1), alkaline phosphatase (ALP) and Gap‐junction protein, alpha 1, 43 kDa (CX43) were expressed, whereas expression of Sp7 transcription factor (OSX), bone morphogenetic protein 2 (BMP2), colony‐stimulating factor 1 (CSF‐1), chemokine (C‐C motif) ligand 2 (MCP1), and OPG was low in all samples. The immunofluorescence localization of CSF‐1, MCP1, osteocalcin (OCN), RANKL, and BMP2 was not specific for either part of the follicles. In conclusion, a consistently high expression of CX43 suggests that gap‐junction communication in HDFCs is essential for the eruption process. Furthermore, the induced expression of RANKL in HDFCs varies significantly between individuals and may relate to clinical variations in tooth eruption.

Periodontal Tissue Bioengineering: Is the Future Now?

Periodontitis affects nearly half of the adult population in the United States and leads to periodontium destruction, tooth loss, and tooth mobility. Novel bioengineering has become an area of interest in dentistry, as various approaches aim to regenerate attachment apparatus around diseased teeth with the use of barriers, scaffolds, bone grafts, or biologics. This article emphasizes recent findings in the fields of stem cell/gene therapy, 3-dimensional printing, and innovative scaffold designs for future applications in clinical care.

Muscle-specific differences in expression and phosphorylation of the Janus kinase 2/Signal Transducer and Activator of Transcription 3 following long-term mechanical ventilation and immobilization in rats

AIM

Muscle wasting is one of the factors most strongly predicting mortality and morbidity in critically ill intensive care unit (ICU). This muscle wasting affects both limb and respiratory muscles, but the understanding of underlying mechanisms and muscle-specific differences remains incomplete. This study aimed at investigating the temporal expression and phosphorylation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway in muscle wasting associated with the ICU condition to characterize the JAK/STAT proteins and the related changes leading or responding to their activation during exposure to the ICU condition.

METHODS

A novel experimental ICU model allowing long-term exposure to the ICU condition, immobilization and mechanical ventilation, was used in this study. Rats were pharmacologically paralysed by post-synaptic neuromuscular blockade and mechanically ventilated for durations varying between 6 hours and 14 days to study muscle-specific differences in the temporal activation of the JAK/STAT pathway in plantaris, intercostal and diaphragm muscles.

RESULTS

The JAK2/STAT3 pathway was significantly activated irrespective of muscle, but muscle-specific differences were observed in the temporal activation pattern between plantaris, intercostal and diaphragm muscles.

CONCLUSION

The JAK2/STAT3 pathway was differentially activated in plantaris, intercostal and diaphragm muscles in response to the ICU condition. Thus, JAK2/STAT3 inhibitors may provide an attractive pharmacological intervention strategy in immobilized ICU patients, but further experimental studies are required in the study of muscle-specific effects on muscle mass and function in response to both short- and long-term exposure to the ICU condition prior to the translation into clinical research and practice.

Gene expression profiles in dental follicles from patients with impacted canines

Animal studies suggest that the dental follicle (DF) plays a major role in tooth eruption. However, the role of the DF during tooth impaction and related root resorptions in adjacent teeth is not clear. The hypothesis for the present study is that expression of regulatory factors involved in the bone remodelling process necessary for tooth eruption may differ between dental follicles from teeth with different clinical situations. We have analysed the gene expression profiles in the DF obtained from impacted canines, with (N = 3) or without (N = 5) signs of root resorption, and from control teeth (normal erupting teeth, mesiodens) (N = 3). DF from 11 patients (mean age: 13 years) obtains at the time of surgical exposure of the tooth. Due to the surgical time point, all teeth were in a late developmental stage. Gene expression related to osteoblast activation/bone formation, osteoclast recruitment and activation was analysed by RTqPCR. Genes related to bone formation (RUNX2, OSX, ALP, OCN, CX43) were highly expressed in all the samples, but osteoclast recruitment/activation markers (OPG, RANKL, MCP-1, CSF-1) were negligible. No apparent patterns or significant differences in gene expression were found between impacted canines, with or without signs of root resorption, or when compared to control teeth. Our results suggest the DF regulation of osteoclastic activity is limited in the late pre-emergent stage of tooth development, irrespective if the tooth is normally erupting or impacted. We suggest that the follicle may have an important regulatory function for alveolar bone formation in the final eruption process and CX43-gap junction communication could be an important signalling pathway.

Weak by the machines: muscle motor protein dysfunction - a side effect of intensive care unit treatment

Intensive care interventions involve periods of mechanical ventilation, sedation and complete mechanical silencing of patients. Critical illness myopathy (CIM) is an ICU-acquired myopathy that is associated with limb muscle weakness, muscle atrophy, electrical silencing of muscle and motor proteinopathy. The hallmark of CIM is a preferential muscle myosin loss due to increased catabolic and reduced anabolic activity. The ubiquitin proteasome pathway plays an important role, apart from recently identified novel mechanisms affecting non-lysosomal protein degradation or autophagy. CIM is not reproduced by pure disuse atrophy, denervation atrophy, steroid-induced atrophy or septic myopathy, although combinations of high-dose steroids and denervation can mimic CIM. New animal models of critical illness and ICU treatment (i.e. mechanical ventilation and complete immobilization) provide novel insights regarding the time course of protein synthesis and degradation alterations, and the role of protective chaperone activities in the process of myosin loss. Altered mechano-signalling seems involved in triggering a major part of myosin loss in experimental CIM models, and passive loading of muscle potently ameliorates the CIM phenotype. We provide a systematic overview of similarities and distinct differences in the signalling pathways involved in triggering muscle atrophy in CIM and isolated trigger factors. As preferential myosin loss is mostly determined from biochemistry analyses providing no spatial resolution of myosin loss processes within myofibres, we also provide first results monitoring myosin signal intensities during experimental ICU intervention using multi-photon Second Harmonic Generation microscopy. Our results confirm that myosin loss is an evenly distributed process within myofibres rather than being confined to hot spots.

Current Concepts of Epigenetics and Its Role in Periodontitis

Purpose

The focus of this review is to provide an overview of the recent findings on the role of epigenetic mechanisms in periodontal disease, including disease susceptibility, progression, and as potential treatment options.

Recent Findings

The findings on the influence of oral pathogens on epigenetic regulation of pathogen recognition receptors, such as Toll-like receptors, as well as pro-inflammatory cytokines suggest an important role for epigenetics in the regulation of the host immune response. Recent studies also show that the epigenetic pattern in periodontitis lesions differ from that of healthy and gingivitis tissue. In addition, these patterns differ between tissues in the same individual. Research is also indicating a role for both DNA methylation and histone acetylation on cells osteogenic differentiation and bone regeneration.

Summary

Knowledge of epigenetic pattern in periodontal diseases may add not only to the knowledge of susceptibility of the disease but may also be a diagnostic tool to identify patients at risk to develop the severe form of periodontitis. In addition, recent research within gene therapy and tissue engineering indicate a role for epigenetics also to improve regeneration of periodontal tissues.

When epigenetics meets bioengineering-A material characteristics and surface topography perspective

The field of tissue engineering and regenerative medicine (TE/RM) involves regeneration of tissues and organs using implantable biomaterials. The term epigenetics refers to changes in gene expression that are not encoded in the DNA sequence, leading to remodeling of the chromatin and activation or inactivation of gene expression. Recently, studies have demonstrated that these modifications are influenced not only by biological cues but also by mechanical and topographical signals. This review highlights the current knowledge on emerging approaches in TE/RM with a focus on the effect of materials and topography on the epigenetic expression pattern in cells with potential impacts on modulating regenerative biology. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2065-2071, 2018.

Expression of TET2 enzyme indicates enhanced epigenetic modification of cells in periodontitis

DNA methylation is an important epigenetic mechanism involved in the regulation of gene expression, and a reduction in DNA methylation influences cell-cycle progression and cell differentiation in inflammatory cells. The aim of the present study was to analyze the DNA-methylation pattern at local and global/systemic levels in patients with periodontitis and gingivitis. Twenty-one subjects with generalized, severe periodontitis and 17 subjects with gingival inflammation but no attachment loss were recruited. Gingival biopsies and peripheral blood samples were collected and prepared for immunohistochemical analysis of 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC), ten-eleven translocation 2 (TET2), and DNA methyltransferase 1 (DNMT1). Whilst a similar pattern for 5mC and 5hmC DNA methylation was found in both types of lesions, a significantly larger proportion of TET2-positive cells was found in periodontitis lesions than in gingivitis lesions. Quantitative real-time PCR analysis showed no differences between gingivitis and periodontitis lesions regarding expression of TET2 and isocitrate dehydrogenase (IDH) genes, while the global level of 5hmC was significantly higher in blood than in tissue in patients with periodontitis. It is suggested that epigenetic changes are more common in periodontitis lesions than in gingivitis lesions and that such changes are tissue specific.

Multigrowth Factor Delivery via Immobilization of Gene Therapy Vectors

Molecules can be immobilized onto biomaterials by a chemical vapor deposition (CVD) coating strategy. Pentafluorophenolester groups react with amine side chains on antibodies, which can selectively immobilize adenoviral vectors for gene delivery of growth factors. These vectors can produce functional proteins within defined regions of biomaterials to produce customizable structures for targeted tissue regeneration.

Regenerative Medicine for Periodontal and Peri-implant Diseases

The balance between bone resorption and bone formation is vital for maintenance and regeneration of alveolar bone and supporting structures around teeth and dental implants. Tissue regeneration in the oral cavity is regulated by multiple cell types, signaling mechanisms, and matrix interactions. A goal for periodontal tissue engineering/regenerative medicine is to restore oral soft and hard tissues through cell, scaffold, and/or signaling approaches to functional and aesthetic oral tissues. Bony defects in the oral cavity can vary significantly, ranging from smaller intrabony lesions resulting from periodontal or peri-implant diseases to large osseous defects that extend through the jaws as a result of trauma, tumor resection, or congenital defects. The disparity in size and location of these alveolar defects is compounded further by patient-specific and environmental factors that contribute to the challenges in periodontal regeneration, peri-implant tissue regeneration, and alveolar ridge reconstruction. Efforts have been made over the last few decades to produce reliable and predictable methods to stimulate bone regeneration in alveolar bone defects. Tissue engineering/regenerative medicine provide new avenues to enhance tissue regeneration by introducing bioactive models or constructing patient-specific substitutes. This review presents an overview of therapies (e.g., protein, gene, and cell based) and biomaterials (e.g., resorbable, nonresorbable, and 3-dimensionally printed) used for alveolar bone engineering around teeth and implants and for implant site development, with emphasis on most recent findings and future directions.

Epigenetic Modifications of Histones in Periodontal Disease

Periodontitis is a chronic infectious disease driven by dysbiosis, an imbalance between commensal bacteria and the host organism. Periodontitis is a leading cause of tooth loss in adults and occurs in about 50% of the US population. In addition to the clinical challenges associated with treating periodontitis, the progression and chronic nature of this disease seriously affect human health. Emerging evidence suggests that periodontitis is associated with mechanisms beyond bacteria-induced protein and tissue degradation. Here, we hypothesize that bacteria are able to induce epigenetic modifications in oral epithelial cells mediated by histone modifications. In this study, we found that dysbiosis in vivo led to epigenetic modifications, including acetylation of histones and downregulation of DNA methyltransferase 1. In addition, in vitro exposure of oral epithelial cells to lipopolysaccharides resulted in histone modifications, activation of transcriptional coactivators, such as p300/CBP, and accumulation of nuclear factor-κB (NF-κB). Given that oral epithelial cells are the first line of defense for the periodontium against bacteria, we also evaluated whether activation of pathogen recognition receptors induced histone modifications. We found that activation of the Toll-like receptors 1, 2, and 4 and the nucleotide-binding oligomerization domain protein 1 induced histone acetylation in oral epithelial cells. Our findings corroborate the emerging concept that epigenetic modifications play a role in the development of periodontitis.

The Sick and the Weak: Neuropathies/Myopathies in the Critically Ill

Critical illness polyneuropathies (CIP) and myopathies (CIM) are common complications of critical illness. Several weakness syndromes are summarized under the term intensive care unit-acquired weakness (ICUAW). We propose a classification of different ICUAW forms (CIM, CIP, sepsis-induced, steroid-denervation myopathy) and pathophysiological mechanisms from clinical and animal model data. Triggers include sepsis, mechanical ventilation, muscle unloading, steroid treatment, or denervation. Some ICUAW forms require stringent diagnostic features; CIM is marked by membrane hypoexcitability, severe atrophy, preferential myosin loss, ultrastructural alterations, and inadequate autophagy activation while myopathies in pure sepsis do not reproduce marked myosin loss. Reduced membrane excitability results from depolarization and ion channel dysfunction. Mitochondrial dysfunction contributes to energy-dependent processes. Ubiquitin proteasome and calpain activation trigger muscle proteolysis and atrophy while protein synthesis is impaired. Myosin loss is more pronounced than actin loss in CIM. Protein quality control is altered by inadequate autophagy. Ca(2+) dysregulation is present through altered Ca(2+) homeostasis. We highlight clinical hallmarks, trigger factors, and potential mechanisms from human studies and animal models that allow separation of risk factors that may trigger distinct mechanisms contributing to weakness. During critical illness, altered inflammatory (cytokines) and metabolic pathways deteriorate muscle function. ICUAW prevention/treatment is limited, e.g., tight glycemic control, delaying nutrition, and early mobilization. Future challenges include identification of primary/secondary events during the time course of critical illness, the interplay between membrane excitability, bioenergetic failure and differential proteolysis, and finding new therapeutic targets by help of tailored animal models.

Presence of CD3-positive T-cells in oral premalignant leukoplakia indicates prevention of cancer transformation

AIM

Leukoplakias (LPLs) are lesions in the oral mucosa that have a potential to transform into oral squamous cell carcinoma (OSCC). As the degree of immunosurveillance may be important for this transformation to occur, the aim of this study was to determine the presence of immune cells in LPLs with dysplasia in relation to later development of OSCC.

MATERIALS AND METHODS

Biopsies from 16 patients with clinical diagnosis of LPL and histopathological diagnosis of hyperkeratosis with dysplasia were immunostained with antibodies to detect CD3(+) T cells, CD1a(+) LCs, Ki-67(+) and p53-expressing cells. Patients were divided into two groups: LPL with dysplasia that transformed into OSCC (LPL-dys) and that which did not (LPL-ca).

RESULTS

Quantitative analyses showed significantly lower numbers of CD3(+) T-cells in LPL-ca than in LPL-dys. No significant differences were detected when comparing LPL-dys and LPL-ca regarding CD1a(+), p53(+) and Ki-67(+) cells.

CONCLUSION

The number of CD3-expressing T-cells may be important for preventing malignant transformation of LPL.

Epigenetics and its role in periodontal diseases: a state-of-the-art review

The immune response to oral bacteria and the subsequent activation of inflammatory signaling is not only dependent on genetic factors. The importance of so-called epigenetic mechanisms presents additional regulatory pathways of genes involved in maintaining chronic inflammation, including gingivitis and periodontitis. The term epigenetics relates to changes in gene expression that are not encoded in the DNA sequence itself and include chemical alterations of DNA and its associated proteins. These changes lead to remodeling of the chromatin and subsequent activation or inactivation of a gene. Epigenetic mechanisms have been found to contribute to disease, including cancer and autoimmune or inflammatory diseases. In this state-of-the art review, the authors provide the latest findings on the involvement of epigenetic modifications in the development of periodontal disease and present emerging therapeutic strategies aimed at epigenetic targets (epidrugs) associated with the disruption of tissue homeostasis and the development of periodontitis.

A study on particles and some microbial markers in waterpipe tobacco smoke

Waterpipe smoking is becoming increasingly popular worldwide. Research has shown that cigarette smoke, in addition to hundreds of carcinogenic and otherwise toxic compounds, may also contain compounds of microbiological origin. In the present study we analyzed waterpipe smoke for some microbial compounds. Both of the two markers studied, viz 3-hydroxy fatty acids of bacterial lipopolysaccharide (LPS) and ergosterol of fungal biomass, were found in waterpipe tobacco, in amounts similar as previously found in cigarette tobacco, and in smoke. Waterpipe mainstream smoke contained on average 1800 pmol LPS and 84.4 ng ergosterol produced per session. An average concentration of 2.8 pmol/m(3) of LPS was found in second hand smoke during a 1-2-h waterpipe smoking session while ergosterol was not detected; corresponding concentrations from smoking five cigarettes were 22.2 pmol/m(3) of LPS and 87.5 ng/m(3) of ergosterol. This is the first time that waterpipe smoking has been shown to create a bioaerosol. In the present study we also found that waterpipe smoking generated several polycyclic aromatic hydrocarbons, carbon monoxide, and high fraction of small (<200 nm) particles that may have adverse effects on human health upon inhalation.