Primary failure of tooth eruption (PFE) is an autosomal dominant disease which mainly affects the eruption of posterior teeth leading to a lateral open bite. A variety of mutants of the type 1 parathormone receptor (PTH1R) was associated with clinical PFE. These mutations can be located in all functional regions of the PTH1R and may also lead to truncated receptors. First investigations with selected mutants using in vitro cell models showed changes of the cellular localization of the mutated receptors as well as dominant negative effects on the wild type PTH1R. This short review summarizes the clinical characteristics of PFE and the problems of therapy. First functional investigations of PTH1R mutants will be discussed.

ZusammenfassungDie primäre Zahndurchbruchsstörung (primary failure of tooth eruption, PFE) ist eine autosomal-dominante Erkrankung welche insbesondere zu einer Störung des Durchbruchs posteriorer Zähne führt und klinisch durch einen seitlich offenen Biss imponiert. Mittlerweile konnten eine Vielzahl von heterozygoten Mutationen des Typ 1 Parathormonrezeptors (PTH1R) mit dem Vorliegen einer PFE in Verbindung gebracht werden. Die Mutationen können alle funktionellen Bereiche des PTH1R erfassen, oder als Deletionsmutanten zu einem verkürzten Rezeptor führen. Erste Untersuchungen mittels in vitro Zellmodellen zeigten Änderungen der Lokalisation des mutierten Rezeptors und dominant negative Effekte auf den Wildtyp-PTH1R.In diesem Übersichtsartikel werden die klinischen Charakteristika der PFE dargestellt und die Problematik der therapeutischen Optionen erörtert. Erste funktionelle Untersuchungen einzelner PTH1R-Mutanten werden erörtert.

Introduction: In this pilot study, we aimed to determine qualitative and quantitative microbiological changes after the implementation of orthodontic appliances. Methods: A total of 10 healthy patients aged 12-15 years were recruited who needed to undergo orthodontic treatment with buccal fixed appliances. Gingival conditions were assessed by the Gingival Index, Periodontal Screening Index, and Sulcus Bleeding Index. Microbiological samples were collected before and 1 week after the start of therapy at premolars and molars of the right upper quadrant. Bacterial species were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Results: The total number of bacteria increased. Six bacterial species were identified that are involved in the development of caries and other infectious processes. The bacteria selectively adapted more efficiently to the new oral milieu compared with the general oral microbial background. There was a significant increase in Streptococcus spp at the premolars and molars. In all individuals, symptoms of inflammation and gingivitis were detected as a response to the bacterial challenge. Conclusion: Orthodontic treatment induces significant changes in the oral microbial flora associated with gingivitis and an enhanced risk for cariogenic reactions within the first days of orthodontic treatment. To prevent or reduce infectious side effects, oral hygiene instructions and control of patients are necessary before and during the beginning of the therapy.

In vitro studies revealed that Porphyromonas gingivalis (Pg), a pathogen intimately associated with the onset and progression of periodontitis, is able to activate platelets, thus linking periodontal inflammation with the endangerment of vascular health. As wild-type Pg strains are characterized by major genetic heterogeneity, the commonness of platelet-activating Pg strains in periodontitis patients is unknown as of yet. Therefore, this study evaluated the platelet activation capacity of wild-type Pg isolates sampled from patients with aggressive periodontitis.METHODS:Extent and velocity of platelet aggregation were determined by light transmission aggregometry. Platelet surface expression of P-selectin was measured by flow cytometry, activation of p38 MAP kinase, and protein kinase C by Western blot using phospho-specific antibodies.RESULTS:Pg isolates displayed high variability regarding extent and velocity of platelet activation, as well as the involved activating pathways. Corresponding results were observed for platelet P-selectin expression, activation of p38 MAP kinase, or protein kinase C. Inhibitors of platelet immune receptor FcγRIIA and protease-activated receptors revealed several, diverging pathways of activation. Some isolates induced platelet aggregation even in the presence of potent therapeutical platelet inhibitors.CONCLUSIONS:Chronic bacteremia involving specific, platelet-activating Pg strains may constitute a substantial hazard for the integrity of cardiovascular health.

AIM:This study assessed the impact of anti-infective periodontal therapy on the status of vascular health.MATERIALS AND METHODS:Periodontal and vascular health of 55 patients with severe untreated chronic periodontitis was evaluated before and 12 months after anti-infective periodontal therapy. Observed parameters were bleeding on probing (BoP), pocket probing depth (PPD), periodontal inflamed surface area index (PISA), pulse wave velocity (PWV), augmentation index (AIx), central pulse pressure (PPao) and peripheral systolic pressure (RRsys).RESULTS:ΔPISA (baseline-12 months) correlated with ΔPWV (τ 0.21; p < .03), ΔAIx (τ 0.29; p < .002) and ΔPPao (τ 0.23; p < .02). ΔBoP% (baseline-12 months) correlated with ΔPWV (τ 0.18; p < .05) and ΔAIx (τ 0.25; p < .01), while mean ΔPPD (baseline-12 months) correlated with ΔPWV (τ 0.24; p < .01) and ΔAIx (τ 0.21; p < .03). Grouping patients evenly into three groups based on tertiles of BoP resolution after 12 months revealed a significant decrease in the observed PWV median value by -0.6 m/s (p < .04) in the best response tertile (ΔBoP ≥ 88%). In the worst response tertile (ΔBoP ≤ 66%), by contrast, significant increase in PPao (+10.5 mmHg; p < .02) and AIx (+5.5; p < .02) was observed.CONCLUSION:Efficacious resolution of periodontal inflammation may beneficially impact on vascular health.

AbstractAimThis randomized controlled trial assessed the impact of Lactobacillus reuteri on pregnancy gingivitis in healthy women.Materials and MethodsForty‐five healthy women (24 test/21 placebo) with pregnancy gingivitis in the third trimester of pregnancy were enrolled. At baseline Gingival Index (GI) and Plaque Index (PlI) were assessed at the Ramfjord teeth and venous blood taken for TNF‐α analysis. Subsequently participants were randomly provided with lozenges to be consumed 2 × daily until birth (approx. 7 weeks) containing ≥108 CFU L. reuteri ATCC PTA 5289 and ≥108 CFU L. reuteri DSM 17938 (test) or being devoid of L. reuteri (placebo). Within 2 days after birth recording of GI, PlI and blood sampling were repeated.ResultsAt baseline, mean GI and mean PlI did not differ significantly between both groups. In the test group mean TNF‐α serum level was significantly (p < 0.02) lower than in the placebo group. At reevaluation, mean GI and mean PlI of the test group were both significantly (p < 0.0001) lower than in the placebo group. Mean TNF‐α serum level did no longer differ significantly between the groups.ConclusionsThe consumption of L. reuteri lozenges may be a useful adjunct in the control of pregnancy gingivitis.

Aim Primary failure of tooth eruption (PFE) is causally linked to heterozygous mutations of the parathyroid hormone receptor (PTH1R) gene. The mutants described so far lead to exchange of amino acids or truncation of the protein that may result in structural changes of the expressed PTH1R. However, functional effects of these mutations have not been investigated yet. Materials and Methods In HEK293 cells, PTH1R wild type was co-transfected with selected PTH1R mutants identified in patients with PFE. The effects on activation of PTH-regulated intracellular signaling pathways were analyzed by ELISA and Western immunoblotting. Differential effects of wild type and mutated PTH1R on TRESK ion channel regulation were analyzed by electrophysiological recordings in Xenopus laevis oocytes. Results In HEK293 cells, activation of PTH1R wild type increases cAMP and in response activates cAMP-stimulated protein kinase as detected by phosphorylation of the vasodilator stimulated phosphoprotein (VASP). In contrast, the PTH1R mutants are functionally inactive and mutant PTH1R/Gly452Glu has a dominant negative effect on the signaling of PTH1R wild type. Confocal imaging revealed that wild type PTH1R is expressed on the cell surface, whereas PTH1R/Gly452Glu mutant is mostly retained inside the cell. Furthermore, in contrast to wild type PTH1R which substantially augmented K+ currents of TRESK channels, coupling of mutated PTH1R to TRESK channels was completely abolished. Conclusions PTH1R mutations affect intracellular PTH-regulated signaling in vitro. In patients with primary failure of tooth eruption defective signaling of PTH1R mutations is suggested to occur in dento-alveolar cells and thus may lead to impaired tooth movement.

AIM This prospective, parallel group, two-armed, double-blind, placebo-controlled randomized trial evaluated the impact of dietary nitrate consumption on gingival inflammation in periodontal recall patients. MATERIAL AND METHODS Forty-four (23 test/21 placebo) periodontal recall patients with chronic gingivitis were enrolled. At baseline, gingival index (GI), plaque control record (PCR) and salivary nitrate level (SNL) were recorded, followed by sub- and supragingival debridement. Subsequently, participants were randomly provided with 100 ml bottles of a lettuce juice beverage to be consumed 3× daily over 14 days, containing either a standardized amount of nitrate resulting in an intake of approximately 200 mg nitrate per day (test) or being devoid of nitrate (placebo). RESULTS At baseline, mean GI, PCR and SNL did not differ significantly between the groups. At day 14, mean GI of the test group was significantly reduced compared to baseline and significantly lower (p = 0.002) than in the placebo group (GI 0.3 versus 0.5). Also, mean SNL in the test group was significantly higher than in the placebo group (54.0 μg/ml versus 27.8 μg/ml; p < 0.035). Mean PCR did not change significantly in both groups. CONCLUSIONS Dietary nitrate consumption may be a useful adjunct in the control of chronic gingivitis.

Aim: This single blind cross-sectional study compared the vascular health of subjects suffering from severe chronic periodontitis, severe aggressive periodontitis and periodontal healthy controls by evaluating pulse wave velocity (PWV), augmentation index (AIx) and pulse pressure amplification (PPA).Material and Methods: In a total of 158 subjects, 92 suffering from severe periodontitis and 66 matched periodontal healthy controls, PWV, AIx, central and peripheral blood pressure were recorded using an oscillometric device (Arteriograph).Results: Subjects suffering from severe chronic or aggressive periodontitis exhibited significantly higher PWV (p = 0.00004), higher AIx (p = 0.0049) and lower PPA (p = 0.028) than matched periodontal healthy controls.Conclusions: The results of this study confirm the association between periodontal inflammation and increased cardiovascular risk shown by impaired vascular health in case of severe periodontitis. As impaired vascular health is a common finding in patients suffering from severe periodontal disease a concomitant routine cardiovascular evaluation may be advised.

OBJECTIVES:Primary failure of tooth eruption (PFE) is a rare autosomal-dominant disease characterized by severe lateral open bite as a consequence of incomplete eruption of posterior teeth. Heterozygous mutations in the parathyroid hormone 1 receptor (PTH1R) gene have been shown to cause PFE likely due to protein haploinsufficiency. To further expand on the mutational spectrum of PFE-associated mutations, we report here on the sequencing results of the PTH1R gene in 70 index PFE cases.MATERIALS AND METHODS:Sanger sequencing of the PTH1R coding exons and their immediate flanking intronic sequences was performed with DNA samples from 70 index PFE cases.RESULTS:We identified a total of 30 unique variants, of which 12 were classified as pathogenic based on their deleterious consequences on PTH1R protein while 16 changes were characterized as unclassified variants with as yet unknown effects on disease pathology. The remaining two variants represent common polymorphisms.CONCLUSIONS:Our data significantly increase the number of presently known unique PFE-causing PTH1R mutations and provide a series of variants with unclear pathogenicity which will require further in vitro assaying to determine their effects on protein structure and function.CLINICAL RELEVANCE:Management of PTH1R-associated PFE is problematic, in particular when teeth are exposed to orthodontic force. Therefore, upon clinical suspicion of PFE, molecular DNA testing is indicated to support decision making for further treatment options.

BACKGROUND:Primary failure of eruption (PFE) may be associated with pathogenic mutations in the PTHR1 gene. It has numerous manifestations and is characterized by severe posterior open bite. However, there are also phenotypically similar types of eruption anomalies not associated with a known pathogenic PTHR1 mutation. The purpose of this study was to evaluate whether a distinction can be made between PTHR1-mutation carriers and noncarriers based on clinical and radiological findings.PATIENTS AND METHODS:A total of 36 patients with suspected PFE diagnoses were included and analyzed in accordance with specific clinical and radiographic criteria. In addition, all patients underwent Sanger DNA sequencing analysis of all coding sequences (and the immediate flanking intronic sequences) of the PTHR1 gene.RESULTS:Of these patients, 23 exhibited a heterozygous pathogenic mutation in the PTHR1 gene (PTHR1-mutation carriers), while molecular genetic analysis revealed nosequence alteration in the other 13 patients (non-PTHR1-mutation carriers). Relevant family histories were obtained from 5 patients in the carrier group; hence, this group included a total of 13 familial and 10 simplex cases. The group of noncarriers revealed no relevant family histories. All patients in the carrier group met six of the clinical and radiographic criteria explored in this study: (1) posterior teeth more often affected; (2) eruption disturbance of an anterior tooth in association with additional posterior-teeth involvement; (3) affected teeth resorbing the alveolar bone located coronal to them; (4) involvement of both deciduous and permanent teeth; (5) impaired vertical alveolar-process growth; and (6) severe subsequent finding of posterior open bite. None of the analyzed criteria were, by contrast, met by all patients in the noncarrier group. All patients in the carrier group could be assigned to one of three classifications indicating the extent of eruption disturbance, whereas 4 of the 13 noncarriers presented none of these three patterns. The clinical and radiographic criteria employed in this study would have correctly identified 10 of the 13 PFE patients in the noncarrier group as possessing no detectable PTHR1 mutation.CONCLUSION:The evaluation of clinical and radiographic characteristics can heighten the specificity of ruling out suspected PTHR1 involvement in PFE patients. A hereditary element of PTHR1-associated PFE is clearly identifiable. More studies with more patients are needed to optimize the sensitivity of this preliminary approach on the differential identification of PTHR1-mutation carriers versus noncarriers by multivariate analysis.

SummaryDespite antibiotic therapy, infections with Neisseria meningitidis still demonstrate a high rate of morbidity and mortality even in developed countries. The fulminant septicaemic course, named Waterhouse-Friderichsen syndrome, with massive haemorrhage into the adrenal glands and widespread petechial bleeding suggest pathophysiological inhibition of platelet function. Our data show that N. meningitidis produces the important physiological platelet inhibitor and cardiovascular signalling molecule nitric oxide (NO), also known as endothelium-derived relaxing factor (EDRF). N. meningitidis-derived NO inhibited ADPinduced platelet aggregation through the activation of soluble guanylyl cyclase (sGC) followed by an increase in platelet cyclic nucleotide levels and subsequent activation of platelet cGMP- and cAMP- depend- ent protein kinases (PKG and PKA). Furthermore, direct measurement of horseradish peroxidase (HRP) passage through a vascular endothelial cell monolayer revealed that N. meningitidis significantly increased endothelial monolayer permeability. Immunfluorescence analysis demonstrated NO dependent disturbances in the structure of endothelial adherens junctions after co-incubation with N. meningitidis. In contrast to platelet inhibition, the NO effects on HBMEC were not mediated by cyclic nucleotides. Our study provides evidence that NO plays an essential role in the pathophysiology of septicaemic meningococcal infection.

The integral role of pathologic platelet activation for progression of atherosclerosis and acute clinical events such as myocardial infarction and stroke has been recognized in the last decades. Consequently, treatment with oral antiplatelet agents - particularly acetylsalicylic acid (ASA) and the thienopyridines clopidogrel and ticlopidine-constitutes a cornerstone in the therapy of vascular diseases. Coronary angioplasty and stent implantation furthermore dramatically improved the therapy of coronary artery disease and especially the treatment of acute myocardial infarction. Sustained success with regard to prevention of reocclusion was achieved when dual antiplatelet therapy had been introduced. This combination of ASA and clopidogrel reduced the risk of stent thrombosis to similar to 1% following elective stenting in stable coronary artery disease. However, targeting more complex lesions or performing the intervention in states of increased platelet reactivity such as in acute coronary syndromes or in diabetic patients is still associated with an increased risk of stent thrombosis. Additionally, incomplete ADP-receptor inhibition by thienopyridine treatment is associated with increased cardiovascular events and mortality after coronary intervention.This review displays the underlying pathophysiology of stent thrombosis and its pharmacological prevention by dual antiplatelet therapy. Furthermore, it discusses the assessment of antiplatelet therapy by different analytical methods and the phenomenon of clopidogrel non-responsiveness. The last part highlights current strategies in improving the efficacy of clopidogrel treatment as well as the next generation anti-platelet substances such as novel thienopyridines and non-thienopyridine P2Y(12)-receptor blocking agents.

Treatment with oral anti-platelet agents constitutes a cornerstone in the therapy of coronary artery disease. Coronary angioplasty and stent implantation improved the therapy of coronary artery disease and especially the treatment of acute myocardial infarction. Implementation of glycoprotein IIb/IIIa inhibition further advanced anti-platelet therapy as a central component in the treatment of acute coronary syndromes. Sustained prevention of reocclusion was achieved when dual anti-platelet therapy had been introduced and reduced the risk of stent thrombosis to ~1% following elective stenting in stable coronary artery disease. However, targeting more complex lesions or performing the intervention in states of increased platelet reactivity such as in acute coronary syn- dromes or in diabetic patients is still associated with a higher risk of stent thrombosis. Additionally, incomplete ADP- receptor inhibition by thienopyridine treatment contributes to increased cardiovascular events and mortality after coronary intervention. This review describes the underlying pathophysiology leading to coronary atherothrombosis and contributing to stent thrombosis as well as the pharmacological approach to prevent it by dual anti-platelet therapy. It summarizes the assess- ment of anti-platelet therapy by different analytical methods such as platelet aggregation, platelet function analyzers, and the platelet reactivity index. Impaired clopidogrel responsiveness and its implication for adverse cardiovascular events and stent thrombosis are discussed. Current strategies in improving the efficacy of clopidogrel treatment as well as the next generation of anti-platelet substances such as novel thienopyridines and non-thienopyridine P2Y12-receptor blocking agents are addressed. Finally, we discuss the potential of von-Willebrand factor aptamers compared to glycoprotein IIb/IIIa inhibitors in acute coronary syndromes.

AimsIncreased risk of thrombo‐embolic events in congestive heart failure (CHF) has been attributed to a hypercoagulable state including vascular endothelial dysfunction and reduced bioavailability of nitric oxide (NO) as well as platelet activation. We investigated whether treatment with a novel endothelial NO synthase (eNOS)‐transcription enhancer positively modulates systemic NO bioavailability and reduces platelet activation in rats with CHF.Methods and resultsAfter experimental myocardial infarction, male Wistar rats were treated with either placebo or the eNOS‐transcription enhancer, AVE9488 (25 ppm/day) for 10 weeks. In rats with severe CHF (left ventricular end‐diastolic pressure >15 mmHg), platelet vasodilator‐stimulated phosphoprotein (VASP)‐phosphorylation reflecting the integrity of the NO/cGMP pathway was significantly reduced (mean immunofluorescence at Ser157: Sham, 61.4 ± 9.1; CHF‐Placebo, 37.4 ± 4.9; P < 0.05; Ser239: Sham, 18.1 ± 2.5; CHF‐Placebo, 13.2 ± 0.6; P < 0.05). Platelet surface expression of P‐selectin and glycoprotein 53 were increased in CHF rats compared with sham‐operated animals. Chronic treatment with AVE9488 significantly enhanced platelet VASP‐phosphorylation in CHF rats (Ser157: 70.4 ± 16.2; Ser239: 19.3 ± 1.8). In parallel, platelet surface expression of P‐selectin and glycoprotein 53 was reduced in the treatment group.ConclusionPlatelet activation was evident in CHF rats. Therapy with the eNOS‐transcription enhancer, AVE9488, reduced platelet activation in parallel to normalization of platelet NO bioavailability.

Incomplete P2Y(12)-inhibition during clopidogrel treatment is associated with increased cardiovascular events and mortality after coronary intervention. We investigated the incidence of impaired individual clopidogrel-responsiveness using a P2Y(12)-specific and pre-treatment-independent assay in a real world situation. One hundred consecutive patients with coronary artery disease (CAD) on combined acetylsalicylic acid and clopidogrel treatment (75 mg/d) and 33 patients on aspirin only were screened for platelet ADP-induced signalling by conventional aggregometry, platelet P-selectin expression and the platelet reactivity index (PRI). Impaired P2Y(12)-specific inhibition by clopidogrel was defined as a PRI > 50%. Functional platelet reactivity was significantly lower in clopidogrel-treated patients compared to controls. Impaired individual response to treatment was diagnosed in 69% of clopidogrel-treated patients. Conventional assessment of maximum ADP-induced platelet aggregation failed to detect impaired P2Y(12) inhibition in 36% of patients identified by PRI to have an impaired clopidogrel response. Impaired clopidogrel response was associated with lower HDL levels and a history of hyperlipidaemia. In conclusion, PRI as a P2Y(12)-Specific assay to evaluate the treatment effect of clopidogrel in patients with CAD revealed insufficient P2Y(12)-inhibition in two thirds of patients in a real-world scenario indicating a markedly higher incidence than previously assumed. PRI detected significantly more patients with impaired response than conventional platelet aggregation.