Bone Density and Trabecular Bone Score Decline Rapidly in the First Year After Bone Marrow Transplantation with a Marked Increase in 10-Year Fracture Risk.

As outcomes from allogeneic bone marrow transplantation (BMT) have improved, prevention of long-term complications, such as fragility fractures, has gained importance. We aimed to assess areal bone mineral density (aBMD) and trabecular bone score (TBS) changes post BMT, and determine their relationship with fracture prevalence. Patients who attended the Royal Melbourne Hospital (RMH) BMT clinic between 2005-2021 were included. Patient characteristics and dual-energy X-ray absorptiometry (DXA) values were collected from the electronic medical record and a survey. TBS iNsight™ was used to calculate TBS for DXA scans performed from 2019 onwards. 337 patients with sequential DXAs were eligible for inclusion. Patients were primarily male (60%) and mean age ± SD was 45.7 ± 13.4 years. The annualised decline in aBMD was greater at the femoral neck (0.066g/cm2 (0.0038-0.17)) and total hip (0.094g/cm2 (0.013-0.19)), compared to the lumbar spine (0.049g/cm2 (- 0.0032-0.16)), p < 0.0001. TBS declined independently of aBMD T-scores at all sites. Eighteen patients (5.3%) sustained 19 fractures over 3884 person-years of follow-up post-transplant (median follow-up 11 years (8.2-15)). This 5.3% fracture prevalence over the median 11-year follow-up period is higher than what would be predicted with FRAX® estimates. Twenty-two patients (6.5%) received antiresorptive therapy, and 9 of 18 (50%) who fractured received or were on antiresorptive therapy. In BMT patients, aBMD and TBS decline rapidly and independently in the first year post BMT. However, FRAX® fracture probability estimates incorporating these values significantly underestimate fracture rates, and antiresorptive treatment rates remain relatively low.

Antenatal health and perinatal outcomes of Pacific Islander women in Australia with and without gestational diabetes: A ten-year retrospective cohort study.

BACKGROUND: Pacific Islander (PI) women in Australia have an increased risk of gestational diabetes (GDM); however, their perinatal outcomes are poorly understood. AIM: The aim was to determine the maternal characteristics and perinatal outcomes of PI women with and without GDM compared to Australian/European (AE)-born women. METHODS: A retrospective analysis of perinatal outcomes of singleton deliveries >20 weeks' gestation between 1 January 2011 and 31 December 2020 was conducted at a tertiary provider (Melbourne, Australia). Antenatal details and birth outcomes were extracted from the Birth Outcome Systems database. t-Tests and χ2, univariate and multivariable logistic regression analyses assessed the relationship between ethnicity and outcomes. RESULTS: Of 52,795 consecutive births, 24,860 AE women (13.3% with GDM) and 1207 PI-born women (20.1% with GDM) were compared. PI women had significantly greater pre-pregnancy body mass index (BMI) and significantly lower rates of smoking and nulliparity. PI women with GDM had higher rates of pre-eclampsia (P < 0.001), large-for-gestational age (LGA) neonates (P = 0.037) and neonatal hypoglycaemia (P = 0.017) but lower rates of small-for-gestational age neonates (P = 0.034). Neonatal intensive care unit (NICU)/special care nursery requirements did not increase. After having adjusted for covariates, PI women's risk of LGA neonates (adjusted odds ratio (aOR): 1.06, 95% confidence interval (CI): 0.86-1.31) was attenuated; however, risk of pre-eclampsia (aOR: 1.49, 95% CI: 1.01-2.21) and neonatal hypoglycaemia (aOR: 1.40, 95% CI: 1.01-1.96) still increased. They were less likely to require a primary caesarean section (aOR: 0.86, 95% CI: 0.73-0.99). CONCLUSION: PI women have higher BMI and GDM rates, contributing to an increased likelihood of adverse perinatal outcomes. BMI is a modifiable risk factor that could be addressed prenatally.

PRECeDe Pilot: Prevention of neonatal respiratory distress with antenatal corticosteroids before elective caesarean section in women with diabetes - a feasibility randomised trial.

OBJECTIVE: The PRECeDe Pilot Trial was designed to determine the feasibility of undertaking a multicentre, randomised controlled trial (RCT) to assess the efficacy of antenatal corticosteroids administration within 7 days before elective caesarean section (CS) in women with pre-gestational diabetes (PGDM) or gestational diabetes (GDM). DESIGN: Triple blind, parallel group, placebo-controlled, pilot RCT. SETTING: Single-centre tertiary maternity hospital in Melbourne, Australia. POPULATION: Pregnant women with PGDM (type 1 or type 2 diabetes) or GDM booked for a planned CS scheduled between 35+0 and 38+6 weeks of gestation. METHODS: Eligible participants were randomised to receive two injections of either betamethasone 11.4 mg or normal saline placebo, 24 hours apart within 7 days before CS scheduled between 35+0 and 38+6 weeks of gestation. MAIN OUTCOME MEASURE: The proportion of eligible women who consented and were randomised. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry ACTRN12619001475134. RESULTS: Of 537 women eligible, 182 were approached and 47 (26%) were recruited. Of these, 22 were allocated to the betamethasone group and 25 were allocated to the placebo group. There were no serious adverse events related to participation. CONCLUSION: It is feasible to undertake a triple-blind, placebo-controlled RCT investigating the efficacy of antenatal corticosteroids in preventing respiratory morbidity in infants of women with PGDM or GDM who are undergoing an elective CS between 35+0 and 38+6 weeks.

Extracorporeal Treatment for Gabapentin and Pregabalin Poisoning: Systematic Review and Recommendations From the EXTRIP Workgroup.

Toxicity from gabapentin and pregabalin overdose is commonly encountered. Treatment is supportive, and the use of extracorporeal treatments (ECTRs) is controversial. The EXTRIP workgroup conducted systematic reviews of the literature and summarized findings following published methods. Thirty-three articles (30 patient reports and 3 pharmacokinetic studies) met the inclusion criteria. High gabapentinoid extracorporeal clearance (>150mL/min) and short elimination half-life (<5 hours) were reported with hemodialysis. The workgroup assessed gabapentin and pregabalin as "dialyzable" for patients with decreased kidney function (quality of the evidence grade as A and B, respectively). Limited clinical data were available (24 patients with gabapentin toxicity and 7 with pregabalin toxicity received ECTR). Severe toxicity, mortality, and sequelae were rare in cases receiving ECTR and in historical controls receiving standard care alone. No clear clinical benefit from ECTR could be identified although major knowledge gaps were acknowledged, as well as costs and harms of ECTR. The EXTRIP workgroup suggests against performing ECTR in addition to standard care rather than standard care alone (weak recommendation, very low quality of evidence) for gabapentinoid poisoning in patients with normal kidney function. If decreased kidney function and coma requiring mechanical ventilation are present, the workgroup suggests performing ECTR in addition to standard care (weak recommendation, very low quality of evidence).

Acute toxicity related to misuse (nonmedical use) of tramadol: Experience of the European Drug Emergencies Network Plus.

Following the development of the tramadol crisis currently affecting countries in the Middle East, and Africa, there has been increasing international interest in the regulation of tramadol. This study investigates the misuse of tramadol in patients presenting to emergency departments across Europe. Data from 32 emergency departments in 21 countries were extracted from the Euro-DEN Plus database for the 4-year period from 1 January 2014 to 31 December 2017. Of the reported 24,957 emergency department presentations, tramadol misuse was reported in 105 (0.4% presentations). Tramadol misuse was most common in Bratislava (Slovakia; n = 11, 7.5% of all presentations to this centre), Riga (Latvia; n = 4, 4.9%) and Munich (Germany; n = 17, 2.9%). On arrival, 14 (13.3%) of presentations were in coma/Glasgow coma score ≤ 8 and 9 of these had a respiratory rate <12 breaths/min. These presentations potentially pose a significant burden on emergency departments with a large proportion requiring admission to hospital for ongoing care.

Ambiguous medical abbreviation study: challenges and opportunities.

BACKGROUND: Healthcare workers often abbreviate for convenience, but ambiguous abbreviations may cause miscommunication, which jeopardises patient care. Robust large-scale research to quantify abbreviation frequency and ambiguity in medical documents is lacking. AIMS: To calculate the frequency of abbreviations used in discharge summaries, the proportion of these abbreviations that are ambiguous and the potential utility of auto-expansion software. METHODS: We designed a software programme to extract all instances of abbreviations from every General Medical Unit discharge summary from the Royal Melbourne Hospital in 2015. We manually expanded abbreviations using published inventories and clinical experience, logging multiple expansions for any abbreviation if identified. Abbreviations were classified based on well defined criteria as standardised and likely to be well understood, or ambiguous. Outcome measures included the range and frequency of standardised and ambiguous abbreviations, and the feasibility of electronic auto-expansion software based on these measures. RESULTS: Of the 1 551 537 words analysed from 2336 documents, 137 997 (8.9%) were abbreviations with 1741 distinct abbreviations identified. Most abbreviations (88.7%) had a single expansion. The most common abbreviation was PO (per os/orally), followed by BD (bis in die/twice daily) and 68.1% of abbreviations were standardised, largely pertaining to pathology/chemicals. This meant, however, that a large proportion (31.9%) of abbreviations (2.8% of all words) were ambiguous. The most common ambiguous abbreviation was Pt (patient/physiotherapy), followed by LFT (liver function test/lung function test). CONCLUSIONS: Close to one-third of abbreviations used in general medical discharge summaries were ambiguous. Electronic auto-expansion of ambiguous abbreviations is likely to reduce miscommunication and improve patient safety.

Impact of the Major Candida glabrata Triazole Resistance Determinants on the Activity of the Novel Investigational Tetrazoles VT-1598 and VT-1161.

VT-1161 and VT-1598 are promising investigational tetrazole antifungals that have shown in vitro and in vivo activity against Candida and other fungi. Candida glabrata is a problematic opportunistic pathogen that is associated with high mortality in invasive infection, as well as both intrinsic and rapidly acquired antifungal resistance. The MICs of VT-1161 and VT-1598 were determined by CLSI methodology to evaluate their in vitro activities against clinical C. glabrata isolates and strains containing individual deletions of the zinc cluster transcription factor genes PDR1 and UPC2A as well as the efflux transporter genes CDR1, PDH1, and SNQ2 Overall, both tetrazoles demonstrated relative activities comparable to those of the tested triazole antifungals against clinical C. glabrata isolates (MIC range, 0.25 to 2 mg/liter and 0.5 to 2 µg/ml for VT-1161 and VT-1598, respectively). Deletion of the PDR1 gene in fluconazole-resistant matched clinical isolate SM3 abolished the decreased susceptibility phenotype completely for both VT-1161 and VT-1598, similarly to the triazoles. UPC2A deletion also increased susceptibility to both triazoles and tetrazoles but to a lesser extent than PDR1 deletion. Of the three major transporter genes regulated by Pdr1, CDR1 deletion resulted in the largest MIC reductions for all agents tested, while PDH1 and SNQ2 deletion individually impacted MICs very little. Overall, both VT-1161 and VT-1598 have comparable activities to those of the available triazoles, and decreased susceptibility to these tetrazoles in C. glabrata is driven by many of the same known resistance mechanisms.

In Vitro Activities of the Novel Investigational Tetrazoles VT-1161 and VT-1598 Compared to the Triazole Antifungals against Azole-Resistant Strains and Clinical Isolates of Candida albicans.

The fungal Cyp51-specific inhibitors VT-1161 and VT-1598 have emerged as promising new therapies to combat fungal infections, including Candida spp. To evaluate their in vitro activities compared to other azoles, MICs were determined by Clinical and Laboratory Standards Institute (CLSI) method for VT-1161, VT-1598, fluconazole, voriconazole, itraconazole, and posaconazole against 68 C. albicans clinical isolates well characterized for azole resistance mechanisms and mutant strains representing individual azole resistance mechanisms. VT-1161 and VT-1598 demonstrated potent activity (geometric mean MICs ≤0.15 µg/ml) against predominantly fluconazole-resistant (≥8 µg/ml) isolates. However, five of 68 isolates exhibited MICs greater than six dilutions (>2 µg/ml) to both tetrazoles compared to fluconazole-susceptible isolates. Four of these isolates likewise exhibited high MICs beyond the upper limit of the assay for all triazoles tested. A premature stop codon in ERG3 likely explained the high-level resistance in one isolate. VT-1598 was effective against strains with hyperactive Tac1, Mrr1, and Upc2 transcription factors and against most ERG11 mutant strains. VT-1161 MICs were elevated compared to the control strain SC5314 for hyperactive Tac1 strains and two strains with Erg11 substitutions (Y132F and Y132F&K143R) but showed activity against hyperactive Mrr1 and Upc2 strains. While mutations affecting Erg3 activity appear to greatly reduce susceptibility to VT-1161 and VT-1598, the elevated MICs of both tetrazoles for four isolates could not be explained by known azole resistance mechanisms, suggesting the presence of undescribed resistance mechanisms to triazole- and tetrazole-based sterol demethylase inhibitors.

The Fungal Cyp51-Specific Inhibitor VT-1598 Demonstrates In Vitro and In Vivo Activity against Candida auris.

Candida auris is an emerging pathogen associated with significant mortality and often multidrug resistance. VT-1598, a tetrazole-based fungal CYP51-specific inhibitor, was evaluated in vitro and in vivo against C. auris Susceptibility testing was performed against 100 clinical isolates of C. auris by broth microdilution. Neutropenic mice were infected intravenously with C. auris, and treatment began 24 h postinoculation with a vehicle control, oral VT-1598 (5, 15, and 50 mg/kg of body weight once daily), oral fluconazole (20 mg/kg once daily), or intraperitoneal caspofungin (10 mg/kg once daily), which continued for 7 days. Fungal burden was assessed in the kidneys and brains on day 8 in the fungal burden arm and on the days the mice succumbed to infection or on day 21 in the survival arm. VT-1598 plasma trough concentrations were also assessed on day 8. VT-1598 demonstrated in vitro activity against C. auris, with a mode MIC of 0.25 µg/ml and MICs ranging from 0.03 to 8 µg/ml. Treatment with VT-1598 resulted in significant and dose-dependent improvements in survival (median survival, 15 and >21 days for VT-1598 at 15 and 50 mg/kg, respectively) and reductions in kidney and brain fungal burden (reductions of 1.88 to 3.61 log10 CFU/g) compared to the control (5 days). The reductions in fungal burden correlated with plasma trough concentrations. Treatment with caspofungin, but not fluconazole, also resulted in significant improvements in survival and reductions in fungal burden compared to those with the control. These results suggest that VT-1598 may be a future option for the treatment of invasive infections caused by C. auris.

The interaction of PRC2 with RNA or chromatin is mutually antagonistic.

Polycomb repressive complex 2 (PRC2) modifies chromatin to maintain genes in a repressed state during development. PRC2 is primarily associated with CpG islands at repressed genes and also possesses RNA binding activity. However, the RNAs that bind PRC2 in cells, the subunits that mediate these interactions, and the role of RNA in PRC2 recruitment to chromatin all remain unclear. By performing iCLIP for PRC2 in comparison with other RNA binding proteins, we show here that PRC2 binds nascent RNA at essentially all active genes. Although interacting with RNA promiscuously, PRC2 binding is enriched at specific locations within RNAs, primarily exon-intron boundaries and the 3' UTR. Deletion of other PRC2 subunits reveals that SUZ12 is sufficient to establish this RNA binding profile. Contrary to prevailing models, we also demonstrate that the interaction of PRC2 with RNA or chromatin is mutually antagonistic in cells and in vitro. RNA degradation in cells triggers PRC2 recruitment to CpG islands at active genes. Correspondingly, the release of PRC2 from chromatin in cells increases RNA binding. Consistent with this, RNA and nucleosomes compete for PRC2 binding in vitro. We propose that RNA prevents PRC2 recruitment to chromatin at active genes and that mutual antagonism between RNA and chromatin underlies the pattern of PRC2 chromatin association across the genome.

Acute myeloid leukaemia presenting with diabetes insipidus.

A 41-year-old man was diagnosed with hypogonadotropic hypogonadism managed with gonadotropins after routine fertility review. Eight months later he presented with new polydipsia and polyuria, lethargy and easy bruising. A full blood count showed 28% circulating blasts. A bone marrow biopsy confirmed a diagnosis of acute myeloid leukaemia with inv(3)(q21.3q26.2) with additional monosomy 7. Central diabetes insipidus (DI) was diagnosed following a water deprivation test. Pituitary magnetic resonance imaging showed a slightly thickened pituitary stalk, stable Rathke's cyst, and new absence of the pituitary bright spot. The patient was commenced on desmopressin and induction chemotherapy, subsequently requiring a bone marrow transplant. Bone marrow examination at 100 days post-transplant revealed cytogenetic remission. All symptoms of DI resolved and magnetic resonance imaging showed return of the posterior bright spot and a pituitary stalk of normal thickness. Biochemical hypogonadotropic hypogonadism persisted but was uninterpretable in the context of systemic illness and recent chemotherapy. DI is a rare complication of haematological malignancies, and the prevalence and pathophysiology of DI in this context are poorly understood. Pathogenic mechanisms proposed include leukaemic infiltration of the pituitary, interference with antidiuretic hormone synthesis, and abnormal thrombopoiesis influencing hormone levels. Particular cytogenetic abnormalities such as inv(3)(q21.3q26.2) and monosomy 7 appear to be more commonly associated with DI and also appear to confer worse outcomes. Aetiologies in the literature remain elusive but as DI is a recognised association of haematological malignancies it should be considered in a patient presenting with polydipsia and polyuria.

Quantifying Use of a Health Virtual Community of Practice for General Practitioners' Continuing Professional Development: A Novel Methodology and Pilot Evaluation.

BACKGROUND: Health care practitioners (HPs), in particular general practitioners (GPs), are increasingly adopting Web-based social media platforms for continuing professional development (CPD). As GPs are restricted by time, distance, and demanding workloads, a health virtual community of practice (HVCoP) is an ideal solution to replace face-to-face CPD with Web-based CPD. However, barriers such as time and work schedules may limit participation in an HVCoP. Furthermore, it is difficult to gauge whether GPs engage actively or passively in HVCoP knowledge-acquisition for Web-based CPD, as GPs' competencies are usually measured with pre- and posttests. OBJECTIVE: This study investigated a method for measuring the engagement features needed for an HVCoP (the Community Fracture Capture [CFC] Learning Hub) for learning and knowledge sharing among GPs for their CPD activity. METHODS: A prototype CFC Learning Hub was developed using an Igloo Web-based social media software platform and involved a convenience sample of GPs interested in bone health topics. This Hub, a secure Web-based community site, included 2 key components: an online discussion forum and a knowledge repository (the Knowledge Hub). The discussion forum contained anonymized case studies (contributed by GP participants) and topical discussions (topics that were not case studies). Using 2 complementary tools (Google Analytics and Igloo Statistical Tool), we characterized individual participating GPs' engagement with the Hub. We measured the GP participants' behavior by quantifying the number of online sessions of the participants, activities undertaken within these online sessions, written posts made per learning topic, and their time spent per topic. We calculated time spent in both active and passive engagement for each topic. RESULTS: Seven GPs participated in the CFC Learning Hub HVCoP from September to November 2017. The complementary tools successfully captured the GP participants' engagement in the Hub. GPs were more active in topics in the discussion forum that had direct clinical application as opposed to didactic, evidence-based discussion topics (ie, topical discussions). From our knowledge hub, About Osteoporosis and Prevention were the most engaging topics, whereas shared decision making was the least active topic. CONCLUSIONS: We showcased a novel complementary analysis method that allowed us to quantify the CFC Learning Hub's usage data into (1) sessions, (2) activities, (3) active or passive time spent, and (4) posts made to evaluate the potential engagement features needed for an HVCoP focused on GP participants' CPD process. Our design and evaluation methods for ongoing use and engagement in this Hub may be useful to evaluate future learning and knowledge-sharing projects for GPs and may allow for extension to other HPs' environments. However, owing to the limited number of GP participants in this study, we suggest that further research with a larger cohort should be performed to validate and extend these findings.

Characterisation of treated effluent from four commonly employed wastewater treatment facilities: A UK case study.

Sewage treatment systems are a common feature across the landscape of the United Kingdom, serving an estimated 96% of the population and discharging approximately eleven billion litres of treated wastewater daily. While large treatment facilities are ubiquitous across the landscape, they are not the only method employed in domestic wastewater treatment. This study investigates whether differences in nutrient export (carbon, nitrogen and phosphorus) and organic matter composition (determined by optical indices, SUVA254, S350-400 and E2:E3) from treated effluent could be detected between four of the most common facilities employed in the treatment of wastewater across the UK. Set in the context of the River Wylye, a small headwater catchment, treatment facilities studied included; a septic tank system, small packet treatment works, and two large sewage treatment works, one of which employed phosphorus stripping for phosphorus removal. Inorganic N and P concentrations ranged between 7.51 and 42.4 mg N l-1 and 0.22 and 8.9 mg P l-1 respectively, with DOC concentrations ranging between 1.63 and 11.8 mg C l-1. Optical indices were comparable to those observed in catchments where organic matter is dominated by autochthonous production, suggesting the dominance of low molecular weight material when compared to values observed across temperate aquatic systems. Combining data from both the Environment Agency and Ordinance Survey we estimate that only 15% of domestic properties not connected to mains sewerage in the study catchment have an Environment Agency consent/exemption permit. This calculation suggests that the quantity of small point sources are significantly underestimated, undermining efforts under current legislation to improve stream ecosystem health.

The Novel Fungal Cyp51 Inhibitor VT-1598 Is Efficacious in Experimental Models of Central Nervous System Coccidioidomycosis Caused by Coccidioides posadasii and Coccidioides immitis.

Coccidioidal meningitis can cause significant morbidity, and lifelong antifungal therapy is often required. VT-1598 is a fungus-specific Cyp51 inhibitor that has potent in vitro activity against Coccidioides species. We evaluated the in vivo efficacy of VT-1598 in murine models of central nervous system coccidioidomycosis caused by C. posadasii and C. immitis Infection was introduced via intracranial inoculation, and therapy began 48 h postinoculation. Oral treatments consisted of vehicle control, VT-1598, and positive controls of fluconazole in the C. immitis study and VT-1161 in the C. posadasii study. Treatment continued for 7 and 14 days in the fungal-burden and survival studies, respectively. Fungal burden was assessed in brain tissue collected 24 to 48 h posttreatment in the fungal-burden studies, on the days the mice succumbed to infection, or at prespecified endpoints in the survival studies. VT-1598 plasma concentrations were also measured in the C. posadasii study. VT-1598 resulted in significant improvements in survival in mice infected with either species. In addition, the fungal burden was significantly reduced in the fungal-burden studies. Plasma concentrations 48 h after dosing stopped remained above the VT-1598 MIC against the C. posadasii isolate, although levels were undetectable in the survival study after a 4-week washout. Whereas fungal burden remained suppressed after a 2-week washout in the C. immitis model, a higher fungal burden was observed in the survival arm of the C. posadasii model. This in vivo efficacy supports human studies to establish the utility of VT-1598 for the treatment of coccidioidomycosis.

Fungal-specific Cyp51 inhibitor VT-1598 demonstrates in vitro activity against Candida and Cryptococcus species, endemic fungi, including Coccidioides species, Aspergillus species and Rhizopus arrhizus.

Background: Invasive fungal infections, including those caused by yeasts, moulds and endemic organisms, can be significant causes of morbidity and mortality in immunocompromised hosts, those with multiple comorbidities and occasionally immunocompetent hosts. Current antifungal agents are often limited by drug toxicities, drug interactions or the development of resistance. VT-1598 is a novel tetrazole that has greater specificity for fungal Cyp51 than currently available triazoles and thus the potential for clinically significant drug interactions is reduced. We measured the in vitro activity of VT-1598 against clinical isolates of Candida and Cryptococcus species, endemic fungi, including Coccidioides, Blastomyces and Histoplasma, Aspergillus species and Rhizopus arrhizus. Methods: Antifungal susceptibility testing was performed by broth microdilution or macrodilution methods per CLSI standards. Clinical isolates of each species were used and clinically available antifungal agents were tested against each isolate. Results: VT-1598 demonstrated in vitro activity against yeasts and moulds that was similar to or greater than that of clinically available antifungal agents, including amphotericin B, fluconazole, caspofungin, voriconazole and posaconazole. The in vitro activity of VT-1598 was also maintained against resistant isolates, including fluconazole-resistant Candida isolates. In vitro activity was also observed against endemic fungi, including Blastomyces, Histoplasma and both Coccidioides immitis and Coccidioides posadasii. Conclusions: VT-1598 demonstrated in vitro activity against yeasts, moulds and endemic fungi, which was maintained against isolates that had reduced susceptibility to other antifungals. Further studies are warranted to evaluate the in vivo efficacy of VT-1598 against various fungal pathogens.

VT-1598 inhibits the in vitro growth of mucosal Candida strains and protects against fluconazole-susceptible and -resistant oral candidiasis in IL-17 signalling-deficient mice.

Background: Chronic mucocutaneous candidiasis (CMC) treatment often induces drug resistance, posing long-term challenges. A novel broad-spectrum fungal CYP51 inhibitor, VT-1598, specifically targets fungal CYP51, but not human CYP enzymes. Objectives: To determine the efficacy of VT-1598 in the treatment of oral Candida infection caused by fluconazole-susceptible and -resistant clinical isolates. Methods: The MICs of VT-1598 and fluconazole for 28 Candida isolates recovered from patients with inherited CMC were determined using CLSI M27-A3 and M27-S4 guidelines. Plasma and tongue VT-1598 or fluconazole concentrations were measured in mice following oral administration to determine tissue distribution. Tongue fungal load was determined in IL-17 signalling-deficient Act1-/- mice following sublingual Candida albicans infection and oral treatment with fluconazole or VT-1598. Results: Among the 28 Candida isolates, 10 (36%) had fluconazole MICs of ≥4 mg/L, whereas VT-1598 demonstrated potent in vitro activity against all isolates (MIC90, 0.125 mg/L). After oral administration, VT-1598 levels in mouse plasma and tongue were significantly greater than those of fluconazole. In vivo, VT-1598 exhibited significant efficacy against fluconazole-susceptible and -resistant C. albicans, even at low drug doses. Furthermore, after a 10 day washout period, tongue fungal burdens in fluconazole-treated mice returned to vehicle control levels, whereas, in contrast, they were undetectable in mice treated with VT-1598. Conclusions: VT-1598 effectively controls in vitro growth of mucosally derived Candida clinical isolates, including fluconazole-resistant strains. In vivo, VT-1598 eliminates C. albicans, even after a long washout period or at low doses. Therefore, VT-1598 is a promising drug candidate that may significantly improve treatment options for CMC patients.

Cousins not twins: intratumoural and intertumoural heterogeneity in syndromic neuroendocrine tumours.

Hereditary endocrine neoplasias, including phaeochromocytoma/paraganglioma and medullary thyroid cancer, are caused by autosomal dominant mutations in several familial cancer genes. A common feature of these diseases is the presentation of multiple primary tumours, or multifocal disease representing independent tumour clones that have arisen from the same initiating genetic lesion, but have undergone independent clonal evolution. Such tumours provide an opportunity to discover common cooperative changes required for tumourigenesis, while controlling for the genetic background of the individual. We performed genomic analysis of synchronous and metachronous tumours from five patients bearing germline mutations in the genes SDHB, RET, and MAX. Using whole exome sequencing and high-density single-nucleotide polymorphism arrays, we analysed two to four primary tumours from each patient. We also applied multi-region sampling, to assess intratumoural heterogeneity and clonal evolution, in two cases involving paraganglioma and medullary thyroid cancer, respectively. Heterogeneous patterns of genomic change existed between synchronous or metachronous tumours, with evidence of branching evolution. We observed striking examples of evolutionary convergence involving the same rare somatic copy-number events in synchronous primary phaeochromocytoma/paraganglioma. Convergent events also occurred during clonal evolution of metastatic medullary thyroid cancer. These observations suggest that genetic or epigenetic changes acquired early within precursor cells, or pre-existing within the genetic background of the individual, create contingencies that determine the evolutionary trajectory of the tumour. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Peripheral Quantitative Computed Tomography (pQCT) Measures Contribute to the Understanding of Bone Fragility in Older Patients With Low-trauma Fracture.

Dual-energy X-ray absorptiometry (DXA) as currently used has limitations in identifying patients with osteoporosis and predicting occurrence of fracture. We aimed to express peripheral quantitative computed tomography (pQCT) variables of patients with low-trauma fracture as T-scores by using T-score scales obtained from healthy young women, and to evaluate the potential clinical utility of pQCT for the assessment of bone fragility. Fracture patients were recruited from a fracture liaison service at the Royal Melbourne Hospital. Reference pQCT data were obtained from studies on women's health conducted by our group. A study visit was arranged with fracture patients, during which DXA and pQCT were applied to measure their bone strength. A total of 59 fracture patients were recruited, and reference data were obtained from 78 healthy young females. All DXA variables and most pQCT variables were significantly different between healthy young females and fracture patients (p < 0.05), except polar stress-strain index (p = 0.34) and cortical bone density (p = 0.19). Fracture patients were divided into osteoporosis and non-osteoporosis groups according to their DXA T-scores. Significant differences were observed in most pQCT variables (p < 0.05), except trabecular area and cortical density (p > 0.9 and p = 0.5, respectively). By applying pQCT T-scores, 11 (27%) of patients who were classified as having low or medium risk of osteoporosis on DXA T-scores alone were reclassified as high risk. Results of logistic regression suggested trabecular bone density as an independent predictor of osteoporosis status. More patients can be identified with osteoporosis by applying pQCT T-score variables in older people with low-trauma fracture. Peripheral QCT T-scores contribute to the understanding of bone fragility in this population.

Crystal Structure of the New Investigational Drug Candidate VT-1598 in Complex with Aspergillus fumigatus Sterol 14α-Demethylase Provides Insights into Its Broad-Spectrum Antifungal Activity.

Within the past few decades, the incidence and complexity of human fungal infections have increased, and therefore, the need for safer and more efficient, broad-spectrum antifungal agents is high. In the study described here, we characterized the new tetrazole-based drug candidate VT-1598 as an inhibitor of sterol 14α-demethylase (CYP51B) from the filamentous fungus Aspergillus fumigatus VT-1598 displayed a high affinity of binding to the enzyme in solution (dissociation constant, 13 ± 1 nM) and in the reconstituted enzymatic reaction was revealed to have an inhibitory potency stronger than the potencies of all other simultaneously tested antifungal drugs, including fluconazole, voriconazole, ketoconazole, and posaconazole. The X-ray structure of the VT-1598/A. fumigatus CYP51 complex was determined and depicts the distinctive binding mode of the inhibitor in the enzyme active site, suggesting the molecular basis of the improved drug potency and broad-spectrum antifungal activity. These data show the formation of an optimized hydrogen bond between the phenoxymethyl oxygen of VT-1598 and the imidazole ring nitrogen of His374, the CYP51 residue that is highly conserved across fungal pathogens and fungus specific. Comparative structural analysis of A. fumigatus CYP51/voriconazole and Candida albicans CYP51/VT-1161 complexes supports the role of H bonding in fungal CYP51/inhibitor complexes and emphasizes the importance of an optimal distance between this interaction and the inhibitor-heme iron interaction. Cellular experiments using two A. fumigatus strains (strains 32820 and 1022) displayed a direct correlation between the effects of the drugs on CYP51B activity and fungal growth inhibition, indicating the noteworthy anti-A. fumigatus potency of VT-1598 and confirming its promise as a broad-spectrum antifungal agent.

Design and optimization of highly-selective, broad spectrum fungal CYP51 inhibitors.

While the orally-active azoles such as fluconazole and posaconazole are effective antifungal agents, they potently inhibit a broad range of off-target human cytochrome P450 enzymes (CYPs) leading to various safety issues (e.g., drug-drug interactions, liver, and reproductive toxicities). Recently we described the rationally-designed, antifungal agent VT-1161 that is more selective for fungal CYP51 than related human CYP enzymes such as CYP3A4. Herein, we describe the use of a homology model of Aspergillus fumigatus to design and optimize a novel series of highly selective, broad spectrum fungal CYP51 inhibitors. This series includes the oral antifungal VT-1598 that exhibits excellent potency against yeast, dermatophyte, and mold fungal pathogens.