P–622 Prothrombotic biomarkers during controlled ovarian stimulation for assisted reproductive techniques

Study question

Does the evolution of prothrombotic biomarkers over time differ between antagonist and long agonist stimulation protocols for assisted reproductive techniques (ART) ?

Summary answer

The hypercoagulable state was higher and persistent in the agonist and antagonist with hCG triggering groups compared to the antagonist with GnRH agonist triggering group.

What is known already

Controlled ovarian stimulation (COS) for ART is associated with supra-physiological serum estradiol levels, a hypercoagulable state and an increased risk of venous thrombosis. Most thromboembolic events associated with COS occur in the context of ovarian hyperstimulation syndrome (OHSS). The use of hCG for final follicular maturation increases the risk of OHSS. In antagonist protocols, GnRH agonist triggering is known to prevent or reduce OHSS and is therefore widely used in women at risk. The impact of the different IVF protocols on pro-thrombotic biomarkers is unknown.

Study design, size, duration

In this prospective observational cohort study, infertile women undergoing COS for ART in 2017–2019 at the University Hospitals of Geneva and Lausanne (Switzerland) were included. We evaluated changes in key coagulation parameters (D-dimers, factor VIII, fibrinogen activity, protein S and protein C) and thrombin generation, our primary outcome, (using 5 pM of tissue factor) by calibrated automated thrombinography before stimulation (T1), on the day of ovulation triggering (T2) and seven days after triggering (T3).

Participants/materials, setting, methods

COS was started without hormonal pre-treatment. Protocols were prescribed according to the standards used in each centre taking into account the risk of OHSS (agonist protocol with hCG trigger in women without OHSS risk (Group 1); antagonist protocol in women at risk of OHSS with hCG trigger (Group 2;) or GnRH agonist trigger (Group 3;); variation of endogenous thrombin potential (ETP) was measured and compared among groups using mixed effects linear regression model.

Main results and the role of chance

A total of 64 women were included: 24 were in group 1, 16 in group 2, and 24 in group 3. The mean age (SD) was 37.8 (2.8), 35.9(5.2) and 34(4.6) years in groups 1, 2 and 3 respectively. As expected, women in group 1 had a statistically lower level of anti-müllerian hormone (p = <0.001), a lower antral follicular count (p = <0.001) and lower number of MII oocytes and embryos obtained (p = <0.001). Mean serum estradiol levels were 1836 (1160), 1628 (815) and 3754 (2165) ng/L at T2, and 945 (471), 1061 (495) and 413 (729) ng/L at T3, in group 1 to 3, respectively. In multivariable regression analysis, the levels in group 3 were statistically higher at T2 and lower at T3 (overall time*group interaction: p < 0.001). The mean ETP was similar between all groups at T1, and increased in all groups at T2 (1442, 1426 and 1486 nM/min in groups 1, 2 and 3, respectively) (p = 0.013). Overall, ETP evolution over time was statistically different between groups, with the lowest increase of ETP between T1 and T3 in group 3. Protein C and protein S levels were stable, while D-dimers, fibrinogen and factor VIII increased at T2 and T3 in all groups.

Limitations, reasons for caution

Stimulation protocols were prescribed according to the clinical profile and OHSS risks; groups therefore differ substantially in regards to age and ovarian reserve. Thromboembolic events are rare events after COS, we therefore evaluated biological markers of hypercoagulability and not clinical events.

Wider implications of the findings: Women with GnRH agonist triggering protocol did not increase mean ETP in the week after ovulation, while women with hCG triggering did. This different prothrombotic profile was independent of the variation of the other coagulation parameters investigated. This effect of ovulation triggering should be confirmed by further studies.

Trial registration number

NCT04188444

P-622 Prothrombotic biomarkers during controlled ovarian stimulation for assisted reproductive techniques

Study question

Does the evolution of prothrombotic biomarkers over time differ between antagonist and long agonist stimulation protocols for assisted reproductive techniques (ART) ?

Summary answer

The hypercoagulable state was higher and persistent in the agonist and antagonist with hCG triggering groups compared to the antagonist with GnRH agonist triggering group.

What is known already

Controlled ovarian stimulation (COS) for ART is associated with supra-physiological serum estradiol levels, a hypercoagulable state and an increased risk of venous thrombosis. Most thromboembolic events associated with COS occur in the context of ovarian hyperstimulation syndrome (OHSS). The use of hCG for final follicular maturation increases the risk of OHSS. In antagonist protocols, GnRH agonist triggering is known to prevent or reduce OHSS and is therefore widely used in women at risk. The impact of the different IVF protocols on pro-thrombotic biomarkers is unknown.

Study design, size, duration

In this prospective observational cohort study, infertile women undergoing COS for ART in 2017-2019 at the University Hospitals of Geneva and Lausanne (Switzerland) were included. We evaluated changes in key coagulation parameters (D-dimers, factor VIII, fibrinogen activity, protein S and protein C) and thrombin generation, our primary outcome, (using 5 pM of tissue factor) by calibrated automated thrombinography before stimulation (T1), on the day of ovulation triggering (T2) and seven days after triggering (T3).

Participants/materials, setting, methods

COS was started without hormonal pre-treatment. Protocols were prescribed according to the standards used in each centre taking into account the risk of OHSS (agonist protocol with hCG trigger in women without OHSS risk (Group 1); antagonist protocol in women at risk of OHSS with hCG trigger (Group 2;) or GnRH agonist trigger (Group 3;); variation of endogenous thrombin potential (ETP) was measured and compared among groups using mixed effects linear regression model.

Main results and the role of chance

A total of 64 women were included: 24 were in group 1, 16 in group 2, and 24 in group 3. The mean age (SD) was 37.8 (2.8), 35.9(5.2) and 34(4.6) years in groups 1, 2 and 3 respectively. As expected, women in group 1 had a statistically lower level of anti-müllerian hormone (p = < 0.001), a lower antral follicular count (p = < 0.001) and lower number of MII oocytes and embryos obtained (p = < 0.001). Mean serum estradiol levels were 1836 (1160), 1628 (815) and 3754 (2165) ng/L at T2, and 945 (471), 1061 (495) and 413 (729) ng/L at T3, in group 1 to 3, respectively. In multivariable regression analysis, the levels in group 3 were statistically higher at T2 and lower at T3 (overall time*group interaction: p < 0.001).

The mean ETP was similar between all groups at T1, and increased in all groups at T2 (1442, 1426 and 1486 nM/min in groups 1, 2 and 3, respectively) (p = 0.013). Overall, ETP evolution over time was statistically different between groups, with the lowest increase of ETP between T1 and T3 in group 3. Protein C and protein S levels were stable, while D-dimers, fibrinogen and factor VIII increased at T2 and T3 in all groups.

Limitations, reasons for caution

Stimulation protocols were prescribed according to the clinical profile and OHSS risks; groups therefore differ substantially in regards to age and ovarian reserve. Thromboembolic events are rare events after COS, we therefore evaluated biological markers of hypercoagulability and not clinical events.

Wider implications of the findings

Women with GnRH agonist triggering protocol did not increase mean ETP in the week after ovulation, while women with hCG triggering did. This different prothrombotic profile was independent of the variation of the other coagulation parameters investigated. This effect of ovulation triggering should be confirmed by further studies.

Trial registration number

NCT04188444

Do miRNAs Have a Role in Platelet Function Regulation?

MicroRNAs (miRNAs) are a class of non-coding RNAs known to repress mRNA translation and subsequent protein production. miRNAs are predicted to modulate many targets and are involved in regulating various cellular processes. Identifying their role in cell function regulation may allow circulating miRNAs to be used as diagnostic or prognostic markers of various diseases. Increasing numbers of clinical studies have shown associations between circulating miRNA levels and platelet reactivity or the recurrence of cardiovascular events. However, these studies differed regarding population selection, sample types used, miRNA quantification procedures, and platelet function assays. Furthermore, they often lacked functional validation of the miRNA identified in such studies. The latter step is essential to identifying causal relationships and understanding if and how miRNAs regulate platelet function. This review describes recent advances in translational research dedicated to identifying miRNAs' roles in platelet function regulation.

Biological properties of Cakile maritima Scop. (Brassicaceae) extracts

OBJECTIVE

Cakile maritima scop. (CKM) is a herbaceous plant (Brassicaceae) growing also in high salinity environment. It is an annual plant growing in clumps or mounds in the sand on beaches and bluffs.

MATERIALS AND METHODS

Stems, seeds, leaves and flowers of CKM were used to obtain 70% of ethanol extracts. The phenolic content of the different extracts was evaluated by the Folin-Ciocalteu method. The separation of phytochemical compounds was based on ultra-performance liquid chromatography coupled to mass spectrometry. Radical scavenging activity was determined by 1,1-diphenyl-2-picrylhydrazyl assay. The qualitative assay for the inhibition of α-glucosidase was quantified spectrophotometrically and the anti-inflammatory activity was determined in the U937 cell line by using gene expression of pro-inflammatory cytokines. Cell viability assay was done in U937, MM1S, and U266 cells by using the 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. The antimicrobial activity was investigated by MIC determination, "double-triple combinations assay", and growth inhibition curves analysis, using the extracts individually or in various combination. Statistical analysis was performed by the Student's t-test and ANOVA.

RESULTS

All parts of the plant exhibited a high antioxidant capacity as measured by DPPH assay. Furthermore, all extracts reduced (about 10 folds) the expression of inflammatory cytokines in macrophage following LPS treatment. As regards the antibacterial activity, only the seeds extract was able to inhibit both Gram-negative and Gram-positive bacteria when tested alone, whereas dual combinations of different extracts (leaves, flowers, stems and seeds) caused bacterial inhibition exhibiting a synergic action. Finally, we showed that the extracts did not exhibit cytotoxic effects in normal cells and that, surprisingly, it exhibited an anti-proliferative effect (inhibition ≈80%) in multiple myeloma U266 cells.

CONCLUSIONS

Our study suggests that CKM possesses antioxidant, anti-inflammatory, antibacterial, anti-proliferative activities and such pleiotropic effects may be exploited under various pathological conditions.

Effects of plasma transfusions on antithrombin levels after paediatric liver transplantation

BACKGROUND AND OBJECTIVES

Thrombotic complications affect 3-10% of patients after liver transplantation (LT), leading to potentially life-threatening complications. In the days following LT, antithrombin (AT) is decreased longer than pro-coagulant factors, thus favouring a pro-thrombotic profile. Plasma transfusions are given empirically in some centres to correct AT levels following LT. We assessed the effect of plasma transfusion on AT levels after paediatric LT.

MATERIALS AND METHODS

Prospective single-centre observational study in 20 consecutive paediatric LT recipients over a 24-month period. Plasma was administered twice daily (10 ml/kg/dose) according to an existing protocol. AT levels were measured once daily, immediately prior to and one hour after the morning plasma transfusion. Sample size was calculated based on a non-inferiority hypothesis.

RESULTS

The median age and weight were 11.6 years (IQR 2.8; 14.7) and 40 kg (IQR 12.75; 44.8), respectively. We collected 85-paired blood samples. The median AT level prior to plasma transfusion was 58%. The median difference in AT levels before and after plasma transfusion was 4.2% (P = 0.001). Changes in AT levels after plasma transfusion were not correlated with baseline AT levels (R = 0.19) or patient weight (R = 0.18).

CONCLUSION

Plasma transfusions only marginally increase AT levels in children after LT. Therefore, prophylactic plasma transfusions probably do not seem to confer an advantage in the routine management of paediatric LT patients. Randomized controlled trials are needed to identify the optimal anticoagulation strategy in this specific population.

Sensorineural Hearing Loss in a Patient Affected by Congenital Cytomegalovirus Infection: Is It Useful to Identify Comorbid Pathologies?

Sensorineural hearing loss (SNHL) is a common defect with a multifactorial etiology. Congenital cytomegalovirus infection (cCMV) is the most common infectious cause, and its early detection allows a prompt pharmacological treatment that can improve hearing prognosis. In a consistent percentage of profound SNHL, genetic causes and/or inner ear malformations are involved; their prompt diagnosis might change therapeutic options. This study reports a case of a 3- year-old female patient with symptomatic cCMV infection who also exhibits developmental delay, dysmorphic facial features, bilateral hearing loss, and cochlear incomplete partition, type 2, in 7q21.3 deletion. This deletion includes the genes DLX5 and DLX6 , which could be the candidate genes for the ear malformation named incomplete partition, type 2.

Accuracy and consistency of anti-Xa activity measurement for determination of rivaroxaban plasma levels

Essentials Accurate determination of anticoagulant plasma concentration is important in clinical practice. We studied the accuracy and consistency of anti-Xa assays for rivaroxaban in a multicentre study. In a range between 50 and 200 μg L-1 , anti-Xa activity correlated well with plasma concentrations. The clinical value might be limited by overestimation and intra- and inter-individual variation.

SUMMARY

Background Determining the plasma level of direct oral anticoagulants reliably is important in the work-up of complex clinical situations. Objectives To study the accuracy and consistency of anti-Xa assays for rivaroxaban plasma concentration in a prospective, multicenter evaluation study employing different reagents and analytical platforms. Methods Rivaroxaban 20 mg was administered once daily to 20 healthy volunteers and blood samples were taken at peak and trough levels (clinicaltrials.gov NCT01710267). Anti-Xa activity was determined in 10 major laboratories using different reagents and analyzers; corresponding rivaroxaban plasma concentrations were measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS). Findings Overall Pearson's correlation coefficient of anti-Xa levels and HPLC-MS results was 0.99 for Biophen® Heparin (95% CI, 0.99, 0.99), Biophen® DiXaI (95% CI, 0.99, 0.99) and STA® anti-Xa liquid (95% CI, 0.99, 1.00). Correlation was lower in rivaroxaban concentrations below 50 μg L-1 and above 200 μg L-1 . The overall bias of the Bland-Altman difference plot was 14.7 μg L-1 for Biophen Heparin, 17.9 μg L-1 for Biophen DiXal and 19.0 μg L-1 for STA anti-Xa liquid. Agreement between laboratories was high at peak level but limited at trough level. Conclusions Anti-Xa activity correlated well with rivaroxaban plasma concentrations, especially in a range between 50 and 200 μg L-1 . However, anti-Xa assays systematically overestimated rivaroxaban concentration as compared with HPLC-MS, particularly at higher concentrations. This overestimation, coupled with an apparent interindividual variation, might affect the interpretation of results in some situations.

Impact of a product-specific reference standard for the measurement of a PEGylated rFVIII activity: the Swiss Multicentre Field Study

INTRODUCTION

Measuring factor VIII (FVIII) activity can be challenging when it has been modified, such as when FVIII is pegylated to increase its circulating half-life. Use of a product-specific reference standard may help avoid this issue.

AIM

Evaluate the impact of using a product-specific reference standard for measuring the FVIII activity of BAX 855 - a pegylated FVIII - in eight of Switzerland's main laboratories.

METHODS

Factor VIII-deficient plasma, spiked with five different concentrations of BAX 855, plus a control FVIII sample, was sent to the participating laboratories. They measured FVIII activity by using either with a one-stage (OSA) or the chromogenic assay (CA) against their local or a product-specific reference standard.

RESULTS

When using a local reference standard, there was an overestimation of BAX 855 activity compared to the target concentrations, both with the OSA and CA. The use of a product-specific reference standard reduced this effect: mean recovery ranged from 127.7% to 213.5% using the OSA with local reference standards, compared to 110% to 183.8% with a product-specific reference standard, and from 146.3% to 182.4% using the CA with local reference standards compared to 72.7% to 103.7% with a product-specific reference standard.

CONCLUSION

In this in vitro study, the type of reference standard had a major impact on the measurement of BAX 855 activity. Evaluation was more accurate and precise when using a product-specific reference standard.

SNORD116 deletions cause Prader-Willi syndrome with a mild phenotype and macrocephaly

Prader-Willi syndrome is a complex condition caused by lack of expression of imprinted genes in the paternally derived region of chromosome 15 (15q11q13). A small number of patients with Prader-Willi phenotype have been discovered to have narrow deletions, not encompassing the whole critical region, but only the SNORD116 cluster, which includes genes codifying for small nucleolar RNAs. This kind of deletion usually is not detected by the classic DNA methylation analysis test. We present the case of a male patient with a mild Prader-Willi phenotype and a small deletion including SNORD116, diagnosed by methylation-sensitive multiplex ligation-dependent probe amplification (MLPA. The patient showed neonatal hypotonia, hyperphagia, obesity, central hypogonadism, hypothyroidism, strabismus. Stature and intellectual development are within the normal range. The presence of macrocephaly, observed in other cases of SNORD116 deletions as well, is uncommon for the classic phenotype of the syndrome.

TiN x O y coatings facilitate the initial adhesion of osteoblasts to create a suitable environment for their proliferation and the recruitment of endothelial cells

Titanium-nitride-oxide coatings (TiN _x O _y ) improve osseointegration of endosseous implants. The exact mechanisms by which these effects are mediated are poorly understood except for an increase of osteoblast proliferation while a high degree of differentiation is maintained. One hypothesis holds that TiN _x O _y facilitates the initial spreading and adhesion of the osteoblasts. The aim of this work was to investigate the molecular mechanisms of osteoblast adhesion on TiN _x O _y as compared to microrough titanium SLA. A global view of the osseointegrative process, that is, taking into account other cell groups, especially endothelial cells, is also presented. To this aim, gene expression and focal adhesion analysis, cocultures and wound assays were performed early after seeding, from 6 h to 3 days. We demonstrated that TiN _x O _y coatings enhance osteoblast adhesion and spreading when compared to the standard microrough titanium. The integrin β1, either in association with α1 or with α2 plays a central role in these mechanisms. TiN _x O _y coatings optimize the process of osseointegration by acting at several levels, especially by upregulating osteoblast adhesion and proliferation, but also by supporting neovascularization and the development of a suitable inflammatory environment.

A multicenter study to assess the reproducibility of antiphospholipid antibody results produced by an automated system

Essentials Inter-lab variation studies for antiphospholipid antibodies (aPL) with the same assay are lacking. We carried out an assessment of repeatability and reproducibility of an automated aPL assay. High intra-center repeatability for anticardiolipin and aβ2 GPI makes duplicate testing unnecessary. Inter-lab reproducibility was high except for aβ2GPI IgG.

SUMMARY

Background Inter-assay variability is a well-known problem in antiphospholipid antibody testing, because of the lack of standardization. Inter-laboratory reproducibility for the same assay is similarly important. Objectives Testing repeatability and reproducibility of HemosIL® AcuStar for anticardiolipin (aCL) and antiβ2-glycoprotein I antibodies (aβ2GPI) IgG and IgM. Patients/Methods In this observational study, out of 420 samples from the thrombophilia centers of Ghent and Geneva, 100 samples were randomly selected and successively analyzed in three centers: Ghent (C1, in duplicate for repeatability evaluation), Geneva (C2) and Frankfurt (C3). Results Results from 99 samples were available, including 25 from patients with antiphospholipid syndrome (APS) and 74 from non-APS patients. The intra-center repeatability expressed as intra-class correlation coefficient (ICC) was higher than 0.99 for each parameter. Differences between two measurements rarely exceeded 1 U mL-1 for values below 100 U mL-1 , except for aβ2GPI IgG, where differences varied from -4 to 4 U mL-1 . The inter-center ICCs were higher than 0.99, except for aCL IgM (ICC = 0.961). These ICCs remained high even when considering values below 100 U mL-1 (0.943, 0.964 and 0.977 for aCL IgG, aCL gM and aβ2GPI IgM, respectively), except for aβ2GPI IgG (ICC = 0.652). Qualitative comparison showed less than 5% discordant classification between centers, with somewhat more discordant results for aβ2GPI IgG. Conclusions In terms of discriminating properties, the HemosIL® AcuStar has excellent intra-center repeatability and a good inter-center reproducibility for aCL IgG, aCL IgM and aβ2GPI IgM. Some concern may arise for aβ2GPI IgG.

Coadministration of ticagrelor and ritonavir: Toward prospective dose adjustment to maintain an optimal platelet inhibition using the PBPK approach

Ticagrelor is a potent antiplatelet drug metabolized by cytochrome (CYP)3A. It is contraindicated in patients with human immunodeficiency virus (HIV) because of the expected CYP3A inhibition by most protease inhibitors, such as ritonavir and an increased bleeding risk. In this study, a physiologically based pharmacokinetic (PBPK) model was created for ticagrelor and its active metabolite (AM). Based on the simulated interaction between ticagrelor 180 mg and ritonavir 100 mg, a lower dose of ticagrelor was calculated to obtain, when coadministered with ritonavir, the same pharmacokinetic (PK) and platelet inhibition as ticagrelor administered alone. A clinical study was thereafter conducted in healthy volunteers. Observed PK profiles of ticagrelor and its AM were successfully predicted with the model. Platelet inhibition was nearly complete in both sessions despite administration of a fourfold lower dose of ticagrelor in the second session. This PBPK model could be prospectively used to broaden the usage of ticagrelor in patients with ritonavir-treated HIV regardless of the CYP3A inhibition.

Functional role of a polymorphism in the Pannexin1 gene in collagen-induced platelet aggregation

Pannexin1 (Panx1) forms ATP channels that play a critical role in the immune response by reinforcing purinergic signal amplification in the immune synapse. Platelets express Panx1 and given the importance of ATP release in platelets, we investigated Panx1 function in platelet aggregation and the potential impact of genetic polymorphisms on Panx1 channels. We show here that Panx1 forms ATP release channels in human platelets and that inhibiting Panx1 channel function with probenecid, mefloquine or specific (10)Panx1 peptides reduces collagen-induced platelet aggregation but not the response induced by arachidonic acid or ADP. These results were confirmed using Panx1-/- platelets. Natural variations have been described in the human Panx1 gene, which are predicted to induce non-conservative amino acid substitutions in its coding sequence. Healthy subjects homozygous for Panx1-400C, display enhanced platelet reactivity in response to collagen compared with those bearing the Panx1-400A allele. Conversely, the frequency of Panx1-400C homozygotes was increased among cardiovascular patients with hyper-reactive platelets compared with patients with hypo-reactive platelets. Exogenous expression of polymorphic Panx1 channels in a Panx-deficient cell line revealed increased basal and stimulated ATP release from cells transfected with Panx1-400C channels compared with Panx1-400A expressing transfectants. In conclusion, we demonstrate a specific role for Panx1 channels in the signalling pathway leading to collagen-induced platelet aggregation. Our study further identifies for the first time an association between a Panx1-400A>C genetic polymorphism and collagen-induced platelet reactivity. The Panx1-400C variant encodes for a gain-of-function channel that may adversely affect atherothrombosis by specifically enhancing collagen-induced ATP release and platelet aggregation.

Refinement of the cutoff values of the HemosIL AcuStar assay for the detection of anticardiolipin and anti-beta2 glycoprotein-1 antibodies

BACKGROUND

The HemosIL AcuStar antiphospholipid assay (Instrumentation Laboratory, Bedford, MA, USA) is a fully automated assay using chemiluminescent technology for the detection of anticardiolipin and anti-beta2 glycoprotein-1 antibodies. This assay showed excellent agreement between results of different laboratories. The cutoff values to define positivity were calculated in 250 healthy blood bank donors but were associated with large confidence intervals (CIs).

OBJECTIVE

The objective of this study was to more precisely determine the cutoff values of the HemosIL AcuStar antiphospholipid assay by increasing the number of healthy blood bank donors through a multicenter study and by applying a normalization procedure of the distribution of each antibody.

METHODS

Five laboratories participated to this study, allowing the inclusion of 626 samples. We used a Box-Cox power transformation method to normalize the distribution and calculate the 99th percentile and the corresponding 95%CI for each antibody.

RESULTS

The revised cutoff values were overall lower than those initially calculated with more stringent CIs and yielded a 4.2% increase in sensitivity with a 2.7% decrease in specificity regarding thrombotic events or obstetric complications.

CONCLUSIONS

We provide refined cutoff values for the detection of anticardiolipin and anti-beta2 glycoprotein-1 antibodies with the HemosIL AcuStar Antiphospholipid assay that should be preferred for routine use.

Effects of fluorotherapy on oral changes caused by a vegan diet

AIM

The aim of this paper was to investigate the effects of fluorotherapy on the oral health of subjects who had been following a vegan diet (lacking in meat and animal derivatives) for a long period of time (at least 1 year and 6 months).

METHODS

A preliminary study (t0) evaluated 50 subjects, all from northern Italy and aged 24-60 years (28 male and 22 female) who had been following a vegan diet for a minimum of 18 months to a maximum of 20 years, and compared them with a control group of 50 individuals following a Mediterranean diet. All vegan subjects showed oral changes such as white spots, lesions invisible to the naked eye and decreased salivary pH values (~5-6). In a second study (t1), the 50 vegan subjects were randomly divided into two subgroups of 25. Subgroup SG1 underwent fluorotherapy with sodium fluoride (Elmex fluoride gel® 1.25%) administered once daily for 1 year. Subgroup SG2 served as controls and did not receive fluorotherapy. The following parameters were recorded before the start of fluorotherapy and again after 1 year: salivary pH; Decayed, Missing, Filled teeth Index; presence and location of white spots and lesions not visible to the naked eye; Plaque Index, and Gingival Index.

RESULTS

In SG1, larger lesions became smaller in diameter and small lesions disappeared, a statistically significant improvement compared with SG2, despite the persistence of restricted eating habits and the oral hygiene conditions being similar to those at t0. Salivary pH showed no significant change in either subgroup.

CONCLUSION

Daily application of a topical 1.25% fluoride gel is effective in reducing the incidence of white spot lesions caused by a vegan diet.

Thrombotic complications of myeloproliferative neoplasms: risk assessment and risk-guided management

Philadelphia-negative myeloproliferative neoplasms are considered to be acquired thrombophilic states. Thromboses, both arterial and venous (not rarely in unusual sites), are often the initial events leading to the diagnosis. After diagnosis, the yearly incidence of thrombotic events is highly variable, and ranges from approximately 1% to 10%. The identification of patients at risk who may benefit from antithrombotic therapy remains a challenge, and it is currently based on age and history of thrombotic events. However, the predictive value of these clinical characteristics is rather limited. Few prospective studies and even fewer interventional randomized studies are available, and there are no studies designed to formally validate the use of risk stratification. The implementation of laboratory parameters such as leukocytosis and/or the JAK2 V617F mutation into a scoring system may be of interest. The mechanisms at work leading to thrombosis remain largely speculative, but are likely to be complex and multifactorial, with a prominent role of cell-cell interactions, mostly owing to qualitative changes. The long-term treatment options to prevent thrombosis are, schematically, aspirin alone as primary prevention for the low-risk patients, and cytoreduction combined with aspirin for the other patients. In very low-risk young essential thrombocythemia patients, abstention can even be considered. The optimal duration of anticoagulation after a thrombotic event is not established. All antithrombotic therapies should be balanced with the hemorrhagic risk, which can also be increased in these patients.

[Perioperative management of new antiplatelet drugs]

The management of antiplatelet drugs in the perioperative setting is based on an individual evaluation of the thrombotic and bleeding risks. When the bleeding risk is deemed low, continuation of the dual antiplatelet therapy is usually recommended, especially in high thrombotic risk settings. When the bleeding risk is deemed moderate, at least one antiplatelet agent should be continued, usually aspirin, and clopidogrel and ticagrelor should be discontinued 5 days and prasugrel 7 days before surgery. In some rare instances of high bleeding risk, discontinuation of aspirin 3 days before surgery is usually acceptable. In high thrombotic settings, bridging with an intravenous antiplatelet drug with a short half-life may be considered.

[New oral anticoagulants: from theory to practice]

Physicians are confronted with many new antithrombotic drugs, either antiplatelet agents or new oral anticoagulants (NOAC). Targets of NOAC are specific (either anti-IIa or antiXa) and clinical studies have shown that NOAC are as efficacious and as safe as "old" anticoagulants (heparin, low molecular weight heparin, vitamin K antagonists); moreover they present some advantages. Indeed, NOAC have a wide therapeutic window and do not require laboratory monitoring. Therefore, it is very tempting to prescribe them on a large scale basis in patients at risk or having thromboembolic diseases. However, things are not so simple in the day-to-day practice and this review aims at answering in a brief and simplified manner to some questions.

The paraoxonase-1 pathway is not a major bioactivation pathway of clopidogrel in vitro

BACKGROUND AND PURPOSE

Clopidogrel is a prodrug bioactivated by cytochrome P450s (CYPs). More recently, paraoxonase-1 (PON1) has been proposed as a major contributor to clopidogrel metabolism. The purpose of this study was to assess the relative contribution of CYPs and PON1 to clopidogrel metabolism in vitro.

EXPERIMENTAL APPROACH

Clopidogrel metabolism was studied in human serum, recombinant PON1 enzyme (rePON1), pooled human liver microsomes (HLMs), HLMs with the CYP2C19*1/*1 genotype and HLMs with the CYP2C19*2/*2 genotype. Inhibition studies were also performed using specific CYP inhibitors and antibodies. Clopidogrel and its metabolites were measured using LC/MS/MS method.

KEY RESULTS

PON1 activity was highest in the human serum and there was no difference in PON1 activity between any of the HLM groups. The production of clopidogrel's active metabolite (clopidogrel-AM) from 2-oxo-clopidogrel in pooled HLMs was approximately 500 times that in serum. When 2-oxo-clopidogrel was incubated with rePON1, clopidogrel-AM was not detected. Clopidogrel-AM production from 2-oxo-clopidogrel was lower in CYP2C19*2/*2 HLMs compared with CYP2C19*1/*1 HLMs, while PON1 activity in HLMs with both genotypes was similar. Moreover, incubation with inhibitors of CYP3A, CYP2B6 and CYP2C19 significantly reduced clopidogrel bioactivation while a PON1 inhibitor, EDTA, had only a weak inhibitory effect.

CONCLUSION AND IMPLICATIONS

This in vitro study shows that the contribution of PON1 to clopidogrel metabolism is limited at clinically relevant concentrations. Moreover, CYP2C19, CYP2B6 and CYP3A play important roles in the bioactivation of clopidogrel.

ELBW infants: to intubate or not to intubate in the delivery room?

Few years ago, elective tracheal intubation in the delivery room was considered as the routine approach in managing respiratory failure in extremely-low-birth-weight infants (ELBW), at least in terms of surfactant administration. Over recent years, the indications and principles of neonatal resuscitation of ELBW infants have been partially reviewed: many randomized clinical trials (RCT) have demonstrated that these infants do not die quickly without intubation in the delivery room, and many infants only need a little help in completing foetal-neonatal transition through the use of lung recruitment manoeuvres in the delivery room (e.g. sustained lung inflation, CPAP) and then only non-invasive ventilation support. Tracheal intubation and mechanical ventilation can be reserved solely for depressed or ELBW, although further RCTs are needed to provide additional information and to provide a conclusive response to the eternal debate as to whether intubation at birth can influence outcome for ELBW infants.

Influence of the paraoxonase-1 Q192R genetic variant on clopidogrel responsiveness and recurrent cardiovascular events: a systematic review and meta-analysis

BACKGROUND

A poor biological response to clopidogrel is associated with an increased risk of major cardiovascular ischemic events (MACE). Paraoxonase 1 (PON1) enzyme activity is modulated by the PON1-Q192R variant (rs662) and was recently suggested to be strongly involved in clopidogrel bioactivation, but the influence of the PON1-Q192R variant on the risk of MACE in clopidogrel-treated patients is controversial.

OBJECTIVES

To determine whether the PON1-Q192R variant influences clopidogrel biological responsiveness and the risk of MACE in patients treated with clopidogrel.

METHODS

Systematic review and meta-analysis of studies of the association between the PON1-Q192R polymorphism and the biological response to clopidogrel and/or the risk of MACE during clopidogrel administration.

RESULTS

Seventeen studies were included. In the 12 studies of the biological response to clopidogrel (n = 5302 patients), there was no significant difference between 192QQ and 192QR + 192RR subjects, whatever the laboratory method used (global mean standardized difference = 0.10 [-0.06; 0.25], P = 0.22). Eleven studies assessed the risk of MACE, four using a case-control design (n = 2739 patients) and seven a prospective design (n = 5353 patients). Overall, MACE occurred in 19% of patients in case-control studies and in 6% of patients in prospective cohort studies, with no significant difference between 192QQ and 192QR + 192RR patients (OR = 1.28 [0.97; 1.68], P = 0.08). Similar results were obtained when study design was taken into account. Heterogeneity was mainly driven by one publication.

CONCLUSIONS

This meta-analysis suggests that the PON1-Q192R polymorphism has no major impact on the risk of MACE and does not alter the biological response to clopidogrel in clopidogrel-treated patients.

Alveolar recruitment in the delivery room

Most preterm babies with a gestational age less than 23-27 weeks need a respiratory support in the delivery room (DR); the aim of ventilation is to create and maintain a functional residual capacity (FRC); to facilitate gas exchange and to minimize acute lung injury. The application of a continuous positive airway pressure (CPAP) from the first breaths helps in obtaining a lung volume stabilization. Efficacy and safety of the application of a sustained lung inflation (SLI) at birth is still under careful evaluation. The prompt increase of the hearth rate and oxygen saturation in the preliminary studies at the moment available in the literature are signs of the good efficacy of the manoeuvre but the effects of the SLI on oxygenation and hemodynamics are undetermined. When preterm infants need respiratory assistance in the DR, respiratory function monitoring is desirable to apply adequate and gentle resuscitation manoeuvres. Clinical large trials taking place in the DR are needed but they are also extremely difficult to be designed and performed.

Clinical predictors of dual aspirin and clopidogrel poor responsiveness in stable cardiovascular patients from the ADRIE study

BACKGROUND

Poor response to both aspirin and clopidogrel (dual poor responsiveness [DPR]) is a major risk factor for recurrent ischemic events.

OBJECTIVES

The aim of this study was to identify factors associated with DPR, defined with specific tests, and derive a predictive clinical score.

METHODS

We studied 771 consecutive stable cardiovascular patients treated with aspirin (n = 223), clopidogrel (n = 111), or both drugs (n = 37). Aspirin responsiveness was evaluated by serum thromboxane (Tx)B₂ assay, and clopidogrel responsiveness by calculating the platelet reactivity index (PRI) on the basis of the phosphorylation status of the vasodilator phosphoprotein. The analysis was focused on patients treated with both drugs, and on independent predictors of DPR.

RESULTS

Among patients on dual therapy, there was no relevant correlation between TxB₂ levels and PRI values (r = 0.11). Sixty-seven patients (15.4%) had DPR. Diabetes [odds ratio (OR) 1.89, 95% confidence interval (CI) 1.06-3.39], high body weight (> 86 kg vs. < 77 kg, OR 4.74, 95% CI 2.49-9.73), low aspirin dose (75-81 mg vs. ≥ 160 mg, OR 0.12, 95% CI 0.09-0.93) and high C-reactive protein (CRP) level (> 1.6 mg L⁻¹ vs. < 0.6 mg L⁻¹, OR 3.66, 95% CI 1.74-8.72) were independently associated with DPR, via increased TxB(2) levels, increased PRI, or both. These associations with TxB₂ and PRI were reproduced across the whole population. With use of a factor-weighed score (c-index = 0.74), the predicted prevalence of DPR was 57% in the highest strata of the score as compared with < 4% for the lowest strata.

CONCLUSIONS

Diabetes, body weight, the aspirin dose and CRP levels are readily available independent predictors of DPR, and some are potential targets for reducing its prevalence.

Oral implications of the vegan diet: observational study

AIM

The aim of this study was to investigate oral changes in subjects who have assumed a vegan diet for a long time (at least 18 months), that is to say, a diet completely lacking in meat and animal derivatives.

METHODS

A sample of 15 subjects was analyzed, all from northern Italy and aged 24 to 60 year, composed of 11 men and 4 women who had been following a vegan diet for a minimum of 18 months to a maximum of 20 years. In parallel with the study sample, a control group (15 subjects) with the same criteria of age, sex, and place of origin all following an omnivorous diet was chosen. The sample answered a questionnaire that investigated their eating habits, the frequency with which they eat meals, the main foodstuffs assumed, oral hygiene habits, and any painful symptomatology of the teeth or more general problems in the oral cavity. The sample was then subject to objective examination in which the saliva pH was measured and the teeth were checked for demineralization of the enamel, white spots, and caries (using KaVo DIAGNOdent) with particular attention being paid to the localization of these lesions, and lastly, sounding was carried out to detect any osseous defects and periodontal pockets.

RESULTS

The study revealed greater incidence of demineralization and white spots in the vegan subjects compared to the omnivorous ones localized at the neck of the teeth and on the vestibular surfaces of dental elements (with the exception of the lower anterior group). The saliva pH, more acid in the omnivorous patients, ranged between four and six. Changes in oral conditions in both groups of subjects were observed.

CONCLUSION

In order to research into the cause-effect relationship of the vegan diet on the oral cavity effectively, the sample needs to be studied for a longer period of time and the results re-evaluated.

Cone beam computed tomography role in diagnosis and treatment of impacted canine patient's: a case report

A tooth is impacted when its apex is formed but does not erupt as expected during the physiological timeframe of eruption. The frequency with which the upper canine is impacted in the sample examined varies from 1% to 5% of the population in the second decade of life. The most frequent causes of inclusion of the upper canine are: lack of resorption or precocious loss of the root of the deciduous, agenesis of the lateral, an anomaly in its shape, lack of space in the arch, presence of a mechanical obstacle to the eruption, and lastly due to hereditary factors. When dental impaction is suspected, radiographic examination is indicated to evaluate the effect that the impacted element is having in the context of the osseous structure and to evaluate its relationships with adjacent teeth, the presence of mechanical obstacles, the placement of the inclusion and its orientation in space, how well developed the root is, and any anomalies in its shape. In addition to the classic orthopantomography (OPT), endoral radiography, teleradiography, can be used in order to obtain three-dimensional and life-size images, techniques of computed tomography (CT). In particular, cone beam CT, obtains this type of image using a radioactive dose comparable to that obtained summarizing the classic radiographic examinations requested by an orthodontist and moreover less that that administered when using classic multi-layer spiral CT medical equipment. This case report describes the diagnostic iter and orthodontic-surgical treatment of a patient with enclosure of the right upper canine.

Clinical implications of clopidogrel non-response in cardiovascular patients: a systematic review and meta-analysis

BSUMMARY BACKGROUND: Previous studies have shown an important risk of cardiovascular events in patients with clopidogrel biological non-response, and data have shown considerable, unexplored heterogeneity.

OBJECTIVES

To evaluate the magnitude of cardiovascular risk associated with clopidogrel non-response and to explore heterogeneity.

METHODS

This was a systematic review and meta-analysis of prospective studies of patients treated with clopidogrel for symptomatic atherothrombosis, evaluated by light transmission aggregometry with ADP and monitored prospectively for clinical ischemic events.

RESULTS

Fifteen studies were included, totaling 3960 patients, of whom 25% were considered to be clopidogrel non-responders. The global relative risk (RR) for recurrent ischemic events in clopidogrel non-responders was 3.5 [95% confidence interval (CI) 2.4-5.2, P < 0.0001]. The results of the different studies were heterogeneous (Cochran P = 0.01 and I(2) = 52%). The most recent studies yielded lower RRs [global RR = 2.9 (95% CI 2.3-3.8) after 2007, and global RR = 6.6 (95% CI 3.7-11.9) before 2007, P = 0.01]. Heterogeneity was present in the group of studies in which more than 10% of patients took glycoprotein (GP)IIb-IIIa inhibitors [Cochran P = 0.003 and I(2) = 70%; RR = 3.8 (95% CI 2.9-5.1)] and was absent in the other studies [Cochran P = 0.88 and I(2) = 0; RR = 2.5 (95% CI 1.7-3.6)]. The RR was significantly higher in studies using higher ADP maximal aggregation cut-offs (> 65%) for clopidogrel non-response than in studies using lower cut-offs [RR = 5.8 (95% CI 3.2-10.3) and RR = 2.9 (95% CI 2.2-3.7), respectively, P = 0.03].

CONCLUSIONS

The risk of ischemic events associated with clopidogrel non-response is now more precisely defined. The risk is heterogeneous across studies, possibly because of an interaction with GPIIb-IIIa inhibitors and the use of different cut-offs to identify non-responders.

[Update on new antithrombotic treatments]

Update on new antithrombotic treatments Antithrombotic treatments are frequently prescribed in different clinical situations. Classical anticoagulants have some disadvantages. New anticoagulants have emerged recently. Fondaparinux is now prescribed for both prophylaxis and treatment of venous thromboembolism. Two drugs are particularly interesting: rivaroxaban and dabigatran. Concerning the new antiplatelet agents, many molecules such as prasugrel, ticagrelor, cangrelor, SCH530348 or terutroban have appeared recently. They are directed either to the P2Y12 receptor or to other original targets. Studies have shown an increased bleeding risk for some of them as well as unexpected side effects. In the next future, these new molecules could allow a more individualised prescription of antithrombotic agents.