TET2 Drives 5hmc Marking of GATA6 and Epigenetically Defines Pancreatic Ductal Adenocarcinoma Transcriptional Subtypes.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) is characterized by advanced disease stage at presentation, aggressive disease biology, and resistance to therapy, resulting in an extremely poor 5-year survival rate of <10%. PDAC is classified into transcriptional subtypes with distinct survival characteristics, although how these arise is not known. Epigenetic deregulation, rather than genetics, has been proposed to underpin progression, but exactly why is unclear and is hindered by the technical limitations of analyzing clinical samples. METHODS: We performed genome-wide epigenetic mapping of DNA modifications 5-methylcytosine and 5-hydroxymethylcytosine (5hmc) using oxidative bisulfite sequencing from formalin-embedded sections. We identified overlap with transcriptional signatures in formalin-fixed, paraffin-embedded tissue from resected patients, via bioinformatics using iCluster and mutational profiling and confirmed them in vivo. RESULTS: We found that aggressive squamous-like PDAC subtypes result from epigenetic inactivation of loci, including GATA6, which promote differentiated classical pancreatic subtypes. We showed that squamous-like PDAC transcriptional subtypes are associated with greater loss of 5hmc due to reduced expression of the 5-methylcytosine hydroxylase TET2. Furthermore, we found that SMAD4 directly supports TET2 levels in classical pancreatic tumors, and loss of SMAD4 expression was associated with reduced 5hmc, GATA6, and squamous-like tumors. Importantly, enhancing TET2 stability using metformin and vitamin C/ascorbic acid restores 5hmc and GATA6 levels, reverting squamous-like tumor phenotypes and WNT-dependence in vitro and in vivo. CONCLUSIONS: We identified epigenetic deregulation of pancreatic differentiation as an underpinning event behind the emergence of transcriptomic subtypes in PDAC. Our data showed that restoring epigenetic control increases biomarkers of classical pancreatic tumors that are associated with improved therapeutic responses and survival.

Tenofovir alafenamide vs. tenofovir disoproxil fumarate: an updated meta-analysis of 14 894 patients across 14 trials.

BACKGROUND: Both tenofovir disoproxil fumarate (TDF)/emtricitabine and tenofovir alafenamide (TAF)/emtricitabine demonstrate excellent efficacy and safety overall, but concerns remain over specific changes in markers of bone and renal function. Lower plasma tenofovir concentrations are seen with TAF and in unboosted regimens. We assess TAF vs. TDF safety with and without booster coformulation. METHODS: A previous systematic review was updated with recent clinical trials. TAF vs. TDF efficacy and safety were compared in boosted and unboosted subgroups. Efficacy was measured by viral suppression. Key safety endpoints included all adverse events, serious adverse events, Grades 3-4 adverse events and adverse event discontinuation. Further specific renal and bone markers were also assessed. RESULTS: A total of 14 clinical trials comparing TDF and TAF regimens were identified. A significant difference (P = 0.0004) in efficacy was shown in the boosted subgroup in favour of TAF, but no difference was seen in the unboosted subgroup. There were no significant differences between TAF and TDF for any of the key safety endpoints analysed. No differences were seen for the bone markers analysed. No difference was found for renal tubular events. There was a difference in risk for discontinuation due to renal adverse events when boosted (P = 0.03), but none when unboosted. CONCLUSION: Across all main safety endpoints, no differences between TAF and TDF are seen. Boosted TDF regimens were associated with lesser comparative efficacy than boosted TAF and a higher risk of renal event discontinuation. However, modern antiretroviral regimens are more commonly unboosted. This study finds no difference in efficacy or safety in unboosted TAF vs. TDF.

The dental management of children with congenital heart disease following the publication of Paediatric Congenital Heart Disease Standards and Specifications.

The Paediatric Congenital Heart Disease Standards and Specifications (PCHDSS) were published in May 2016 by NHS England. The standards describe in detail the cardiac care patients should expect in England. They are also the first cardiology standards to include an oral health section. The dental standards outline what oral health care patients should receive from both cardiology and dental healthcare professionals, with immediate effect. Children with congenital heart disease (CHD) are at increased risk of infective endocarditis and often have poorer oral health compared to healthy children. Children with cardiac disease can be complex to manage appropriately due to their increased dental anxiety and reduced access to dental care. The PCHDSS dental section highlights the importance of collaborative working between cardiology, primary care and paediatric dentistry. This should ensure preventive advice is delivered regularly, oral disease diagnosed early and patients managed or referred appropriately. This article will summarise CHD, the PCHDSS, its implications and discuss the oral health of children with a cardiac defect. The importance of treatment planning and dental management for this high risk group, in addition to informing readers when to refer to specialist care will also be described.

PROTAC-Mediated Degradation of Bruton's Tyrosine Kinase Is Inhibited by Covalent Binding.

The impact of covalent binding on PROTAC-mediated degradation of BTK was investigated through the preparation of both covalent binding and reversible binding PROTACs derived from the covalent BTK inhibitor ibrutinib. It was determined that a covalent binding PROTAC inhibited BTK degradation despite evidence of target engagement, while BTK degradation was observed with a reversible binding PROTAC. These observations were consistently found when PROTACs that were able to recruit either IAP or cereblon E3 ligases were employed. Proteomics analysis determined that the use of a covalently bound PROTAC did not result in the degradation of covalently bound targets, while degradation was observed for some reversibly bound targets. This observation highlights the importance of catalysis for successful PROTAC-mediated degradation and highlights a potential caveat for the use of covalent target binders in PROTAC design.

How safe is TDF/FTC as PrEP? A systematic review and meta-analysis of the risk of adverse events in 13 randomised trials of PrEP.

BACKGROUND: Tenofovir/emtricitabine (TDF/FTC) used as pre-exposure prophylaxis (PrEP) has proven benefits in preventing HIV infection. Widespread use of TDF/FTC can only be justified if the preventative benefits outweigh potential risks of adverse events. A previous meta-analysis of TDF/FTC compared to alternative tenofovir alafenamide (TAF)/FTC for treatment found no significant difference in safety endpoints when used without ritonavir or cobicistat, but more evidence around the safety of TDF/FTC is needed to address concerns and inform widespread use. METHODS: A systematic review identified 13 randomised trials of PrEP, using either TDF/FTC or TDF, versus placebo or no treatment: VOICE, PROUD, IPERGAY, FEM-PrEP, TDF-2, iPrEX, IAVI Kenya, IAVI Uganda, PrEPare, PARTNERS, US Safety study, Bangkok TDF study, W African TDF study. The number of participants with grade 3/4 adverse events or serious adverse events (SAEs) was compared between treatment and control in the meta-analysis. Further analyses of specific renal and bone markers were also undertaken, with fractures as a marker of bone effects and creatinine elevations as a surrogate marker for renal impairment. Analyses were stratified by study duration (1 year of follow up). RESULTS: The 13 randomised trials included 15,678 participants in relevant treatment and control arms. Three studies assessed TDF use only. The number of participants with grade 3/4 adverse events was 1306/7504 (17.4%) on treatment versus 1259/7502 (16.8%) on control (difference=0%, 95% confidence interval [CI] -1% to +2%). The number of participants with SAEs was 740/7843 (9.4%) on treatment versus 795/7835 (10.1%) on no treatment (difference=0%, 95% CI -1% to +1%). The number of participants with creatinine elevations was 8/7843 on treatment versus 4/7835 on control (difference=0%, 95% CI 0%-0%). The number of participants with bone fractures was 217/5789 on treatment versus 189/5795 on control (difference=0%, 95% CI 0% to 1%). There was no difference in outcome between studies with <1 versus >1 year of randomised treatment. CONCLUSIONS: In this meta-analysis of 13 randomised clinical trials of PrEP in 15,678 participants, there was no significant difference in risk of grade 3/4 clinical adverse events or SAEs between TDF/FTC (or TDF) and control. Furthermore, there was no significant difference in risk of specific renal or bone adverse outcomes. The favourable safety profile of TDF/FTC would support more widespread use PrEP in populations with a lower risk of HIV infection.

Tenofovir alafenamide versus tenofovir disoproxil fumarate: is there a true difference in efficacy and safety?

BACKGROUND: Higher plasma tenofovir concentrations are associated with higher risks of renal and bone adverse events. The pharmacokinetic boosters ritonavir (RTV) and cobicistat (COBI) significantly increase plasma area under the curve (AUC) concentrations of tenofovir disoproxil fumarate (TDF), by 25-37%. When combined with RTV or COBI, the dose of tenofovir alafenamide (TAF) is lowered from 25 mg to 10 mg daily, but the TDF dose is maintained at 300 mg daily. OBJECTIVE: To assess the differences in safety and efficacy between tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) in regimens with and without the pharmacokinetic boosters RTV and COBI. METHODS: A PubMed/Embase search inclusive of dates up to 17 July 2017 identified 11 randomised head-to-head trials (8111 patients) of TDF versus TAF. The Mantel-Haenszel method was used to calculate pooled risk differences and 95% confidence intervals using random-effects models. A pre-defined sub-group analysis compared TAF with TDF, either when boosted with RTV or COBI, or when unboosted. RESULTS: Nine clinical trials compared TAF and TDF for treatment of HIV-1 and two were for hepatitis B treatment. The eleven clinical trials documented 4574 patients with boosting RTV or COBI in both arms, covering 7198 patient-years of follow-up. Some 3537 patients received unboosted regimens, totalling 3595 patient-years of follow-up. Boosted TDF-treated patients showed borderline lower HIV RNA suppression <50 copies/mL (P=0.05), more bone fractures (P=0.04), larger decreases in bone mineral density (P<0.001), and more discontinuations for bone (P=0.03) or renal (P=0.002) adverse events. By contrast, there were no significant differences in HIV RNA suppression rates or clinical safety endpoints between unboosted TAF and unboosted TDF. CONCLUSIONS: TDF boosted with RTV or COBI was associated with higher risks of bone and renal adverse events, and lower HIV RNA suppression rates, compared with TAF. By contrast, when ritonavir and cobicistat were not used, there were no efficacy differences between TAF and TDF, and marginal differences in safety. The health economic value of TAF versus low-cost generic TDF may be limited when these drugs are used without cobicistat or ritonavir.

Risks of cardiovascular or central nervous system adverse events and immune reconstitution inflammatory syndrome, for dolutegravir versus other antiretrovirals: meta-analysis of randomized trials.

PURPOSE OF REVIEW: Results from nonrandomized cohort studies suggest higher risks of CNS adverse events for dolutegravir, versus other ARVs. There have been two case reports of myocarditis on dolutegravir. Integrase inhibitors have been associated with IRIS in two cohort studies. Meta-analysis of randomized trials can be used to cross-check potential safety signals. This systematic review of drug safety used an EMBASE and MEDLINE search combined with serious adverse event (SAE) reports on the website www.clinicaltrials.gov. Cardiovascular, CNS or IRIS-associated adverse events were analysed for dolutegravir versus other ARVs. Relative risks for the comparison between dolutegravir and other antiretrovirals were calculated for each adverse event. Meta-analyses applied Mantel-Haenszel random-effects models. RECENT FINDINGS: There was a higher risk of Grade 1-4 insomnia adverse events for DTG (6.1%) versus other ARVs (4.5%; P = 0.02). There was no significant difference between DTG and other ARVs in the risk of cardiovascular serious adverse events. In the SINGLE and SPRING-1 trials comparing DTG with efavirenz, there were 5/465 patients with reported suicidality SAEs on DTG (1.1%) versus 6/469 (1.3%) on EFV. In other studies, serious adverse events of suicidality were reported for 15/2250 patients on DTG (0.7%) versus 9/2257 patients on other ARVs (0.4%). Risks of IRIS were low, but event rates were low and the main trials excluded CDC stage C disease. SUMMARY: In this meta-analysis, there was no significant effect of dolutegravir on the risk of cardiac, IRIS or suicide-related serious adverse events. There was a higher risk of insomnia for DTG. Other completed randomized trials should be included in new evaluations of DTG safety. Continued pharmacovigilance, with regular meta-analyses, should be used to monitor safety.

Management of Recurrent Aphthous Stomatitis in Children.

Recurrent oral ulceration is common and may present in childhood. Causes of recurrent oral ulceration are numerous and there may be an association with underlying systemic disease. Recurrent aphthous stomatitis (RAS) is the most common underlying diagnosis in children. The discomfort of oral ulcers can impact negatively on quality of life of a child, interfering with eating, speaking and may result in missed school days. The role of the general dental practitioner is to identify patients who can be treated with simple measures in primary dental care and those who require assessment and treatment in secondary care. Management may include topical agents for symptomatic relief, topical corticosteroids and, in severe recalcitrant cases, systemic agents may be necessary.

Solid lipid excipients - matrix agents for sustained drug delivery.

Lipid excipients are attracting interest from drug developers due to their performance, ease of use, versatility and their potential to generate intellectual property through innovation in drug delivery particularly in the case of modifying drug release systems. Many articles have described the use of lipid excipients to develop matrix modified release dosage forms in a range of processing techniques, therefore a comprehensive review is timely to collect together and analyze key information. This review article focuses on the utility of lipid excipients in solid sustained drug delivery systems with emphasis on the efficiency and robustness of these systems with respect to: (i) the choice of the manufacturing process and impact on drug release, (ii) the fundamental drug release mechanisms, (iii) resistance of the drug formulation under physiological conditions and (iv) long-term stability. Understanding the functionality of these versatile excipients in formulation is elementary for the development of highly robust lipid-based sustained release medicines.

Real-time assessment of cigarette smoke particle deposition in vitro.

BACKGROUND: Recently there has been a rapid increase in approaches to assess the effects of cigarette smoke in vitro. Despite a range of gravimetric and chemical methods, there is a requirement to identify simpler and more reliable methods to quantify in vitro whole smoke dose, to support extrapolation and comparisons to human/in vivo dose. We have previously characterised an in vitro exposure system using a Borgwaldt RM20S smoking machine and a chamber exposing cellular cultures to whole smoke at the air-liquid interface. In this study we demonstrate the utility of a quartz crystal microbalance (QCM), using this exposure system, to assess real-time cigarette smoke particulate deposition during a 30 minute smoke exposure. Smoke was generated at various dilutions (1:5-1:400, smoke:air) using two cigarette products, 3R4F Kentucky reference and 1 mg commercially available cigarettes. The QCM, integrated into the chamber, assessed particulate deposition and data generated were compared to traditional chemical spectrofluorometric analysis. RESULTS: The QCM chamber was able to detect mass differences between the different products within the nanogram range. 3R4F reference cigarette smoke deposition ranged from 25.75 ±2.30 µg/cm2 (1:5) to 0.22 ±0.03 µg/cm2 (1:400). 1 mg cigarette smoke deposition was less and ranged from 1.42 ±0.26 µg/cm2 (1:5), to 0.13 ±0.02 µg/cm2 (1:100). Spectrofluorometric analysis demonstrated statistically significant correlation of particulate deposition with the QCM (p < 0.05), and regression R2 value were 97.4 %. The fitted equation for the linear model which describes the relationship is: QCM = -0.6796 + 0.9744 chemical spectrofluorescence. CONCLUSIONS: We suggest the QCM is a reliable, effective and simple tool that can be used to quantify smoke particulate deposition in real-time, in vitro and can be used to quantify other aerosols delivered to our chamber for assessment.