Bilingualism in children with a dual diagnosis of Down syndrome and Autism Spectrum Disorder

Research shows that a substantial proportion of children with Down syndrome (DS) also meet the clinical criteria for Autism Spectrum Disorder (ASD). Children with this dual diagnosis display a linguistic profile that includes significant language delays and language impairments which often differ from the impairments observed in each developmental disability (DD) separately. Given the challenges observed with language acquisition for children with DS-ASD, concerns might be raised regarding the outcomes and suitability of a bilingual environment for children with this dual diagnosis specifically. The aim of this research was to explore the language profiles of four children with DS-ASD. A multiple case-study approach was employed. Four children with a confirmed DS-ASD diagnosis who had received exposure to two languages (English and Welsh) were assessed on a range of cognitive and linguistic measures. Performance was compared to three control groups; bilinguals with DS, English monolinguals with DS and mental age-matched typically developing bilinguals. Assessments comprised of expressive and receptive language, phonological awareness, working memory and non-verbal cognitive abilities. Considerable variability was found in the cognitive and linguistic profiles of the case-study participants. Children with DS-ASD displayed similar language profiles to that of the bilingual and monolingual children with DS in the areas tested, although performance was generally lower than that of the TD bilingual children. Although substantial variability was found, participants were developing bilingual abilities in a similar trajectory to children with DS in line with the degree of exposure to each language. This research highlights the need to assess bilingual children with complex dual diagnoses with an individualistic approach and carefully consider how to appropriately assess and treat bilingual children within speech and language therapy provisions.

AIP variant causing familial prolactinoma

Pathogenic variants in the aryl hydrocarbon receptor-interacting protein (AIP) gene are increasingly recognised as a cause of familial isolated pituitary adenoma. AIP-associated tumours are most commonly growth hormone (GH) producing. In our cohort of 175 AIP mutation positive patients representing 93 kindreds, 139 (79%) have GH excess, 19 have prolactinoma (17 familial and 2 sporadic cases) and out of the 17 clinically non-functioning tumours 4 were subsequently operated and found to be GH or GH & prolactin immunopositive adenoma. Here we report a family with an AIP variant, in which multiple family members are affected by prolactinoma, but none with GH excess. To our knowledge this is the first reported family with an AIP pathogenic variant to be affected solely by prolactinoma. These data suggest that prolactinoma families represent a small subset of AIP mutation positive kindreds, and similar to young-onset sporadic prolactinomas, AIP screening would be indicated.

Catheter-related complications and mortality of atrial fibrillation ablation following introduction of contact force-sensing technology

OBJECTIVES

Contact force-sensing catheters allow real-time catheter-tissue contact force monitoring during atrial fibrillation. These catheters were rapidly adopted into clinical practice following market introduction in 2014, but concerns have been raised regarding collateral damage such as esophageal injury. We sought to examine whether the introduction of force-sensing catheters was associated with a change in short-term and intermediate-term acute care use, complications and mortality following atrial fibrillation ablation.

DESIGN

Retrospective cohort analysis. We used inverse probability treatment weight matching to account for the differences in baseline characteristics between groups.

SETTING

We examined patients included in the OptumLabs Data Warehouse who underwent ablation for atrial fibrillation before (2011-2013) and after (2015-2017) the market introduction of contact force-sensing catheters.

MAIN OUTCOME MEASURES

We examined 30-day and 90-day rates of all-cause acute care use, including hospitalizations and emergency department visits, as well as death and hospitalization for catheter-related complications, including atrioesophageal fistula, pericarditis, cardiac tamponade/perforation and stroke/transient ischemic attack.

RESULTS

Our sample included 3470 and 5772 patients who underwent atrial fibrillation (AF) ablation before and after market introduction of contact force-sensing catheters, respectively. Complication rates were low and did not differ between the two periods (p>0.10 for each outcome). The 30-day and 90-day mortality was 0.1% and 0.3%, respectively after market introduction and unchanged from prior to 2014. The 90-day rates of all-cause acute care use decreased, from 27.0% in 2011-2013 to 23.9% in 2015-2017 (p<0.001).

CONCLUSIONS

AF ablation-related catheter complications and mortality are low and there has been no significant change following the introduction of force-sensing catheters.

Development of Anti-CD32b Antibodies with Enhanced Fc Function for the Treatment of B and Plasma Cell Malignancies

The sole inhibitory Fcγ receptor CD32b (FcγRIIb) is expressed throughout B and plasma cell development and on their malignant counterparts. CD32b expression on malignant B cells is known to provide a mechanism of resistance to rituximab that can be ameliorated with a CD32b-blocking antibody. CD32b, therefore, represents an attractive tumor antigen for targeting with a monoclonal antibody (mAb). To this end, two anti-CD32b mAbs, NVS32b1 and NVS32b2, were developed. Their complementarity-determining regions (CDR) bind the CD32b Fc binding domain with high specificity and affinity while the Fc region is afucosylated to enhance activation of FcγRIIIa on immune effector cells. The NVS32b mAbs selectively target CD32b⁺ malignant cells and healthy B cells but not myeloid cells. They mediate potent killing of opsonized CD32b⁺ cells via antibody-dependent cellular cytotoxicity and phagocytosis (ADCC and ADCP) as well as complement-dependent cytotoxicity (CDC). In addition, NVS32b CDRs block the CD32b Fc-binding domain, thereby minimizing CD32b-mediated resistance to therapeutic mAbs including rituximab, obinutuzumab, and daratumumab. NVS32b mAbs demonstrate robust antitumor activity against CD32b⁺ xenografts in vivo and immunomodulatory activity including recruitment of macrophages to the tumor and enhancement of dendritic cell maturation in response to immune complexes. Finally, the activity of NVS32b mAbs on CD32b⁺ primary malignant B and plasma cells was confirmed using samples from patients with B-cell chronic lymphocytic leukemia (CLL) and multiple myeloma. The findings indicate the promising potential of NVS32b mAbs as a single agent or in combination with other mAb therapeutics for patients with CD32b⁺ malignant cells.

Application of a likelihood ratio test based method for safety signal detection to left ventricular assist devices

Effective post-market safety surveillance of medical devices is critical for public health. However, many current statistical methods for safety signal detection do not control for type I error when assessing multiple device and adverse event (AE) combinations. This can result in increased false signals, underscoring the need for more robust statistical methods. Moreover, the duration of medical device use can be an important factor to consider in safety surveillance. In this study, we adapted a likelihood ratio test (LRT) based method, which was initially developed and applied to drugs, to identify safety signals for left ventricular assist devices (LVAD). Among patients with chronic, advanced left ventricular failure, we analyzed AE data for HeartWare and HeartMate II patients during a two-year period and further incorporated person-years (henceforth exposure-time). The novel modified LRT and conventional Z-test with p-values adjusted by the Benjamini-Hochberg (BH) procedure were used to explore safety signals by comparing HeartWare and HeartMate II patients in the presence of multiple adverse events. Both methods identified greater incidence of stroke among HeartWare as compared to HeartMate II patients without exposure-time (p = .025 for LRT and p = .027 for Z-test with BH) and with exposure-time (p = .002 for LRT and p = .005 for Z-test with BH). By using improved statistical methods for safety signal detection, potential safety issues can be identified and addressed in a more timely manner to enhance public safety.

Neurovascular protection in voltage-gated proton channel Hv1 knock-out rats after ischemic stroke: interaction with Na+ /H+ exchanger-1 antagonism

Experimental studies have demonstrated protective effects of NHE‐1 inhibition on cardiac function; however, clinical trials utilizing NHE‐1 antagonists found an increase in overall mortality attributed to thromboembolic strokes. NADPH oxidase‐derived reactive oxygen species (ROS) from microglial cells have been shown to contribute to injury following stroke. We have recently demonstrated that NHE‐1 inhibition enhances ROS in macrophages in a Hv1‐dependent manner. As Hv1 protein is highly expressed in microglia, we hypothesized that “NHE‐1 inhibition may augment neurovascular injury by activating Hv1,” providing a potential mechanism for the deleterious effects of NHE‐1. The goal of this study was to determine whether neurovascular injury and functional outcomes after experimental stroke differed in wild‐type and Hv1 mutant Dahl salt‐sensitive rats treated with an NHE‐1 inhibitor. Stroke was induced using both transient and permanent of middle cerebral artery occlusion (MCAO). Animals received vehicle or NHE‐1 inhibitor KR32568 (2 mg/kg, iv) either 30 min after the start of MCAO or were pretreated (2 mg/kg, iv, day) for 3 days and then subjected to MCAO. Our data indicate that Hv1 deletion confers both neuronal and vascular protection after ischemia. In contrast to our hypothesis, inhibition of NHE‐1 provided further protection from ischemic stroke, and the beneficial effects of both pre‐ and post‐treatment with KR32568 were similar in wild‐type and Hv1^−/− rats. These data indicate that Hv1 activation is unlikely to be responsible for the increased incidence of cerebrovascular events observed in the heart disease patients after NHE‐1 inhibition treatment.

Non-photopic and photopic visual cycles differentially regulate immediate, early, and late phases of cone photoreceptor-mediated vision

Cone photoreceptors in the retina enable vision over a wide range of light intensities. However, the processes enabling cone vision in bright light (i.e. photopic vision) are not adequately understood. Chromophore regeneration of cone photopigments may require the retinal pigment epithelium (RPE) and/or retinal Müller glia. In the RPE, isomerization of all-trans-retinyl esters to 11-cis-retinol is mediated by the retinoid isomerohydrolase Rpe65. A putative alternative retinoid isomerase, dihydroceramide desaturase-1 (DES1), is expressed in RPE and Müller cells. The retinol-isomerase activities of Rpe65 and Des1 are inhibited by emixustat and fenretinide, respectively. Here, we tested the effects of these visual cycle inhibitors on immediate, early, and late phases of cone photopic vision. In zebrafish larvae raised under cyclic light conditions, fenretinide impaired late cone photopic vision, while the emixustat-treated zebrafish unexpectedly had normal vision. In contrast, emixustat-treated larvae raised under extensive dark-adaptation displayed significantly attenuated immediate photopic vision concomitant with significantly reduced 11-cis-retinaldehyde (11cRAL). Following 30 min of light, early photopic vision was recovered, despite 11cRAL levels remaining significantly reduced. Defects in immediate cone photopic vision were rescued in emixustat- or fenretinide-treated larvae following exogenous 9-cis-retinaldehyde supplementation. Genetic knockout of Des1 (degs1) or retinaldehyde-binding protein 1b (rlbp1b) did not eliminate photopic vision in zebrafish. Our findings define molecular and temporal requirements of the nonphotopic or photopic visual cycles for mediating vision in bright light.

Abstract WP492: Differential Effects of Iron Chelation With Deferoxamine on Post-Stroke Neurovascular Inflammation: Disease and Sex Interactions

We have shown that 1) poor recovery in diabetes is associated with greater hemorrhagic transformation and significant loss of the cerebrovasculature, and 2) iron chelation therapy with deferoxamine (DFX) improves sensorimotor and cognitive outcomes while preventing vasoregression in male diabetic animals after stroke. This study tested the hypotheses that 1) diabetes mediates pathological post-stroke neovascularization in females and 2) DFX attenuates microglial activation and pathological neurovascular remodeling in both sexes. Control and diabetic animals were subjected to embolic middle cerebral artery occlusion (MCAO). DFX (100 mg/kg) or vehicle was given 1hour after MCAO and repeated every 12h for 7 days after stroke. Functional outcomes were assessed over time. Vascular indices, microglial morphology (activation), and neurovascular integrity (IgG and unpolarized Aquaporin-4) were measured at Day 14. Male and female microvascular endothelial cells (BMVECs) treated with iron and/or DFX were tested for viability and endothelial mesenchymal transition (EndMT) markers. DFX preserved vascular volume post-stroke in diabetic males. Stroke did not cause vasoregression in diabetic female animals; however, DFX reduced vascular indices while improving sensorimotor but not cognitive outcomes in both control and diabetic females. Ischemic injury amplified microglial activation and neurovascular remodeling in diabetes while DFX treatment restored these changes to control levels in male diabetic animals but not in females (Table). Female BMVECs grown under diabetic conditions expressed α-SMA and N-cadherin while VE-cadherin was decreased, indicative of EndMT (p<0.05 vs normal glucose). Data suggest that DFX treatment has sex- and disease-dependent effects on post-stroke neovascularization. Additional studies will aim to address the mechanisms by which DFX exerts these differential effects on functional outcomes and neurovascular remodeling.

Liquid Chromatographic Method for Determination of Diquat and Paraquat Herbicides in Potatoes: Collaborative Study

A liquid chromatographic (LC) method for the determination of diquat and paraquat herbicides/desiccants in potatoes was collaboratively studied in 6 laboratories. Analytes are extracted from 5 g sample with dilute acid by using a microreflux procedure; the hydrolysate is adjusted to pH 9–10 and passed through a disposable silica cartridge for rapid cleanup and preconcentration. Analytes are separated on a reversed-phase LC column and are measured as their heptanesulfonate ion pairs by UV detection. Each collaborator determined diquat and paraquat at 4 levels (0.05,0.1,0.5, and 1.0 ppm) in blind duplicate samples plus 2 blind negative control samples. Potatoes, obtained from each participant’s region, were spiked by the collaborators with unknown aqueous solutions containing no analyte or a mixture of diquat and paraquat standards. Repeatability and reproducibility relative standard deviations (RSDr and RSDR) averaged 17.1 and 29.0%, respectively, for determination of diquat and 10.8 and 29.5%, respectively, for paraquat. For analysis of standard solutions, RSDr and RSDR values were 6.3 and 12.0%, respectively, for diquat and 7.3 and 13.9%, respectively, for paraquat. Accuracy, measured by comparison with true spiking values (absolute recovery) averaged 77.6 and 76.2% for diquat and paraquat, respectively, and ranged from 71.8 to 88.0% for both compounds. The method was adopted first action by AOAC International.

Abstract C028: Discovery and characterization of next generation monoclonal antibodies targeting the inhibitory Fc gamma receptor CD32b for the treatment of B and plasma cell malignancies

CD32b (FcγR2b), the sole inhibitory Fcγ receptor, negatively regulates immune function and is expressed throughout B cell development and on their malignant counterparts with the highest expression found on multiple myeloma. Additionally, CD32b expression on tumor cells is known to sequester IgG Fc thereby providing a mechanism of resistance to therapeutic monoclonal antibodies (mAb) with Fc dependent activity. Taken together, CD32b represents an attractive tumor antigen for targeting with a mAb. To this end, two anti-CD32b mAbs, NVS32b1 and NVS32b2, were developed. The complementarity-determining regions (CDRs) of these antibodies bind the CD32b Fc binding domain with high specificity and affinity while the Fc region is afucosylated enabling enhanced activation of FcγR on immune effector cells. This specificity and optimized potency is highlighted in whole blood assays where NVS32b2 depletes CD32b positive B cells but spares immune subsets with low CD32b expression or expression of the homologous CD32a. The antibodies mediate potent killing of opsonized cells via antibody dependent cell-mediated cytotoxicity, antibody dependent cellular phagocytosis, and complement dependent cytotoxicity. Additionally, NVS32b mAbs’ CDR block the CD32b Fc binding domain, thereby minimizing CD32b mediated resistance to therapeutic mAbs with Fc dependent activity including rituximab, obinutuzumab, and daratumumab. In vivo, NVS32b mAbs demonstrate robust antitumor activity against CD32b positive xenografts and immunomodulatory activity including recruitment of intratumoral macrophages. The NVS32b mAbs’ activity against malignant B and plasma cells featuring a range of CD32b expression demonstrates their therapeutic potential, as a single agent or in combination with therapeutics including mAbs with Fc dependent activity.

Citation Format: Haihui Lu, Dongshu Chen, Sunyoung Jang, Babette Wolf, Stefan Ewert, Meghan Flaherty, Fangmin Xu, Sinan Isim, Yeonjiu Shim, Christina Dornelas, Nicole Balke, Xavier Charles Leber, Meike Scharenberg, Johanna Koelln, Eugene Choi, Rebecca Ward, Jennifer Johnson, Thomas Calzascia, Isabelle Isnardi, Juliet Williams, Heather Huet, Emma Lees, Matthew J Meyer. Discovery and characterization of next generation monoclonal antibodies targeting the inhibitory Fc gamma receptor CD32b for the treatment of B and plasma cell malignancies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C028. doi:10.1158/1535-7163.TARG-19-C028

AGEN2373 is a conditionally-active agonist antibody targeting the costimulatory receptor CD137 for the treatment of human malignancies

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Background: Agonist antibodies targeting CD137 are potent inducers of tumor-reactive T cell proliferation, cytokine production, and cytotoxicity, and have been explored clinically for their ability to enhance immune cell-mediated destruction of tumor cells. Despite early signs of clinical activity, the development of first-generation anti-CD137 antibodies has been hampered by on-target dose-limiting hepatotoxicity or poor clinical activity. Subsequent CD137 therapies have therefore sought to localize CD137 agonism to the tumor microenvironment (TME) to potentially improve tolerability in patients. However, these approaches may also limit the potential benefit of CD137 signaling outside the TME that contributes to anti-tumor immunity, such as T cell priming in tumor draining lymph nodes. Here we describe the pharmacologic and non-clinical safety profile of a next-generation anti-CD137 monospecific antibody, AGEN2373. Methods: Flow cytometry and surface plasmon resonance-based binding, superantigen-driven immune cell activation, and luminescent reporter cell line assays were developed to test the ability of AGEN2373 to induce CD137 signaling. A non-clinical, multi-dose safety study was conducted wherein cynomolgus monkeys were injected intravenously with 100 mg/kg doses of AGEN2373. Results: AGEN2373 engages cell-expressed human and cynomolgus monkey CD137, and provides potent CD137 co-stimulation only in the presence of CD137 ligand and/or Fc gamma receptor-expressing antigen presenting cells. No changes in clinical parameters, importantly no sign of liver toxicity, were observed after administration of AGEN2373 in cynomolgus monkeys. Conclusions: AGEN2373, a novel conditionally-active anti-CD137 agonist antibody that is well-tolerated in non-human primates, is expected to have clinical activity in patients with human malignancies by its ability to selectively enhance tumor immunity in the context of immune co-stimulation.

Preclinical functional characterization of AGEN1181, a clinical stage Fc-engineered anti-CTLA-4 antibody for the treatment of patients with early and advanced malignancies

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Background: Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) is an inhibitory receptor that modulates T cell priming and CD28-dependent T cell activation. Modulation of this pathway by CTLA-4 antibodies has demonstrated clinical responses in patients with advance disease, however the mechanism of action of these antibodies remains controversial. It is currently understood that anti-CTLA-4 antibodies mediate antitumor effects through receptor-ligand blockade, and, in preclinical models, through depletion of intratumoral regulatory T (Treg) cells via an Fc-dependent mechanism. Recently, we reported a novel Fc-mediated contribution to T cell priming underscored the importance of Fc selection for optimal CTLA-4 antibody activity. AGEN1181 is a clinical stage Fc-engineered IgG1 antibody that leverages this novel mechanism for enhanced functionality. Methods: Fab-mediated biology of AGEN1181 was confirmed by assessing binding affinity, specificity, and blockade of CTLA-4:CD80/86 interactions. Fc-mediated functions of AGEN1181 were evaluated by FcγR binding, reporter-based FcγR signaling, and antibody-mediated Treg cell cytotoxicity assays. In vitro and in vivo pharmacology of AGEN1181 (alone or in combination with anti-PD-1) were evaluated in superantigen (staphylococcal enterotoxin)-mediated T cell stimulation assays and in a non-human primate (NHP) model. Safety and tolerability of AGEN1181 were assessed in cynomolgus monkeys administered 5 once-weekly intravenous bolus infusions at doses of 5, 30, or 100 mg/kg. Results: AGEN1181 bound to CTLA-4 with high affinity and specificity and demonstrated a range of enhanced functional activities relative to first-generation CTLA-4 antibodies. This included superior CD16 (FcγRIIIA) binding, Treg depletion and T cell priming (as measured by ZAP70 phosphorylation and interleukin-2 secretion). In NHP studies, a single dose of AGEN1181, alone or in combination with anti-PD-1 antibody upregulated Ki67 and ICOS expression on peripheral T cells. Finally, AGEN1181 exhibited an acceptable toxicologic profile in multi-dose NHP studies. Conclusions: AGEN1181, an Fc-engineered anti-CTLA-4 antibody exhibits a range of enhanced functional attributes relative to first-generation anti-CTLA-4 antibodies in preclinical studies. Phase 1 clinical studies for AGEN1181 will be initiated imminently.

Non-aqueous formulations for ram and screen extrusion-spheronisation

The use of non-aqueous cellulose-based formulations for extrusion-spheronisation (E-S) is investigated. A 10 wt% hydroxypropyl cellulose/isopropyl alcohol solution (HPC/IPA) was identified as a suitable sticky liquid binder for preparing non-aqueous pastes. Preliminary tests were performed on a series of pastes using a ram as well as a laboratory roller screen extruder, since the former is commonly used in batch testing and the latter replicates the shear range in a manufacturing screen extruder. Pellets with acceptable size and shape distributions were obtained with Avicel® HFE-102 NF/HPC/IPA for ram E-S, and with Avicel® RC-591/HPC/IPA for screen E-S. Further investigation was performed with calcium carbonate added as a model active pharmaceutical ingredient. Both formulations were able to generate pellets with acceptable size and shape characteristics at up to 50 wt% carbonate loading: further work is required to optimise yields.

NLRP3 inflammasome inhibition with MCC950 improves diabetes-mediated cognitive impairment and vasoneuronal remodeling after ischemia

Diabetes increases the risk and worsens the progression of cognitive impairment via the greater occurrence of small vessel disease and stroke. Yet, the underlying mechanisms are not fully understood. It is now accepted that cardiovascular health is critical for brain health and any neurorestorative approaches to prevent/delay cognitive deficits should target the conceptual neurovascular unit (NVU) rather than neurons alone. We have recently shown that there is augmented hippocampal NVU remodeling after a remote ischemic injury in diabetes. NLRP3 inflammasome signaling has been implicated in the development of diabetes and neurodegenerative diseases, but little is known about the impact of NLRP3 activation on functional and structural interaction within the NVU of hippocampus, a critical part of the brain that is involved in forming, organizing, and storing memories. Endothelial cells are at the center of the NVU and produce trophic factors such as brain derived neurotrophic factor (BDNF) contributing to neuronal survival, known as vasotrophic coupling. Therefore, the aims of this study focused on two hypotheses: 1) diabetes negatively impacts hippocampal NVU remodeling and worsens cognitive outcome after stroke, and 2) NLRP3 inhibition with MCC950 will improve NVU remodeling and cognitive outcome following stroke via vasotrophic (un)coupling between endothelial cells and hippocampal neurons. Stroke was induced through a 90-min transient middle cerebral artery occlusion (MCAO) in control and high-fat diet/streptozotocin-induced (HFD/STZ) diabetic male Wistar rats. Saline or MCC950 (3 mg/kg), an inhibitor of NLRP3, was injected at 1 and 3 h after reperfusion. Cognition was assessed over time and neuronal density, blood-brain barrier (BBB) permeability as well as NVU remodeling (aquaporin-4 [AQP4] polarity) was measured on day 14 after stroke. BDNF was measured in endothelial and hippocampal neuronal cultures under hypoxic and diabetes-mimicking condition with and without NLRP3 inhibition. Diabetes increased neuronal degeneration and BBB permeability, disrupted AQP4 polarity, impaired cognitive function and amplified NLRP3 activation after ischemia. Inhibition with MCC950 improved cognitive function and vascular integrity after stroke in diabetic animals and prevented hypoxia-mediated decrease in BDNF secretion. These results are the first to provide essential data showing MCC950 has the potential to become a therapeutic to prevent neurovascular remodeling and worsened cognitive decline in diabetic patients following stroke.

Pharmacological restoration of visual function in a zebrafish model of von-Hippel Lindau disease

Von Hippel-Lindau (VHL) syndrome is a rare, autosomal dominant disorder, characterised by hypervascularised tumour formation in multiple organ systems. Vision loss associated with retinal capillary hemangioblastomas remains one of the earliest complications of VHL disease. The mortality of Vhl^-/- mice in utero restricted modelling of VHL disease in this mammalian model. Zebrafish harbouring a recessive germline mutation in the vhl gene represent a viable, alternative vertebrate model to investigate associated ocular loss-of-function phenotypes. Previous studies reported neovascularisation of the brain, eye and trunk together with oedema in the vhl^-/- zebrafish eye. In this study, we demonstrate vhl^-/- zebrafish almost entirely lack visual function. Furthermore, hyaloid vasculature networks in the vhl^-/- eye are improperly formed and this phenotype is concomitant with development of an ectopic intraretinal vasculature. Sunitinib malate, a multi tyrosine kinase inhibitor, market authorised for cancer, reversed the ocular behavioural and morphological phenotypes observed in vhl^-/- zebrafish. We conclude that the zebrafish vhl gene contributes to an endogenous molecular barrier that prevents development of intraretinal vasculature, and that pharmacological intervention with sunitinib can improve visual function and hyaloid vessel patterning while reducing abnormally formed ectopic intraretinal vessels in vhl^-/- zebrafish.

Association of Genetic Variants in NUDT15 With Thiopurine-Induced Myelosuppression in Patients With Inflammatory Bowel Disease

IMPORTANCE

Use of thiopurines may be limited by myelosuppression. TPMT pharmacogenetic testing identifies only 25% of at-risk patients of European ancestry. Among patients of East Asian ancestry, NUDT15 variants are associated with thiopurine-induced myelosuppression (TIM).

OBJECTIVE

To identify genetic variants associated with TIM among patients of European ancestry with inflammatory bowel disease (IBD).

DESIGN, SETTING, AND PARTICIPANTS

Case-control study of 491 patients affected by TIM and 679 thiopurine-tolerant unaffected patients who were recruited from 89 international sites between March 2012 and November 2015. Genome-wide association studies (GWAS) and exome-wide association studies (EWAS) were conducted in patients of European ancestry. The replication cohort comprised 73 patients affected by TIM and 840 thiopurine-tolerant unaffected patients.

EXPOSURES

Genetic variants associated with TIM.

MAIN OUTCOMES AND MEASURES

Thiopurine-induced myelosuppression, defined as a decline in absolute white blood cell count to 2.5 × 109/L or less or a decline in absolute neutrophil cell count to 1.0 × 109/L or less leading to a dose reduction or drug withdrawal.

RESULTS

Among 1077 patients (398 affected and 679 unaffected; median age at IBD diagnosis, 31.0 years [interquartile range, 21.2 to 44.1 years]; 540 [50%] women; 602 [56%] diagnosed as having Crohn disease), 919 (311 affected and 608 unaffected) were included in the GWAS analysis and 961 (328 affected and 633 unaffected) in the EWAS analysis. The GWAS analysis confirmed association of TPMT (chromosome 6, rs11969064) with TIM (30.5% [95/311] affected vs 16.4% [100/608] unaffected patients; odds ratio [OR], 2.3 [95% CI, 1.7 to 3.1], P = 5.2 × 10-9). The EWAS analysis demonstrated an association with an in-frame deletion in NUDT15 (chromosome 13, rs746071566) and TIM (5.8% [19/328] affected vs 0.2% [1/633] unaffected patients; OR, 38.2 [95% CI, 5.1 to 286.1], P = 1.3 × 10-8), which was replicated in a different cohort (2.7% [2/73] affected vs 0.2% [2/840] unaffected patients; OR, 11.8 [95% CI, 1.6 to 85.0], P = .03). Carriage of any of 3 coding NUDT15 variants was associated with an increased risk (OR, 27.3 [95% CI, 9.3 to 116.7], P = 1.1 × 10-7) of TIM, independent of TPMT genotype and thiopurine dose.

CONCLUSIONS AND RELEVANCE

Among patients of European ancestry with IBD, variants in NUDT15 were associated with increased risk of TIM. These findings suggest that NUDT15 genotyping may be considered prior to initiation of thiopurine therapy; however, further study including additional validation in independent cohorts is required.

Abstract 106: NLRP3 Inflammasome Inhibition With MCC950 Improves Diabetes-Mediated Cognitive Impairment and Vasoneuronal Remodeling After Ischemia

Diabetes increases the risk and worsens the progression of cognitive impairment via the greater occurrence of small vessel disease and stroke. While NLRP3 inflammasome signaling has been implicated in the development of neurodegenerative diseases, little is known about the impact of NLRP3 activation on functional and structural interaction within the neurovascular unit (NVU) in diabetes. Endothelial cells are at the center of NVU and produce trophic factors such as BDNF contributing to neuronal survival, known as vasotrophic coupling. Therefore, the goals of this study were to determine the role of NLRP3 activation: 1) on hippocampal NVU remodeling and cognitive outcome after stroke in diabetes, and 2) on vasotrophic uncoupling between endothelial cells and hippocampal neurons after hypoxic injury in diabetes-mimicking conditions. Control and high-fat diet/STZ induced diabetic male rats were treated with saline or MCC950 (3mg/kg), a small molecule inhibitor of NLRP3, after reperfusion following a 90-min MCAO. Cognition was assessed. Neuronal death, blood-brain barrier (BBB) permeability and glial remodeling was measured on Day 14 after stroke. BDNF was measured in endothelial and hippocampal cell cultures under hypoxic and diabetes-mimicking condition with and without NLRP3 inhibition. Diabetes increased neuronal degeneration, BBB permeability, disrupted AQP4 polarity, impaired cognitive function and increased NLRP3 activation after ischemia. Inhibition with MCC950 improved cognitive function and NVU indices after stroke in diabetic animals and prevented hypoxia-mediated decrease in BDNF secretion. These results are the first to provide essential data showing MCC950 has the potential to become a therapeutic to prevent neurovascular remodeling and worsened cognitive decline in diabetic patients following stroke.