Two-Year Results After AAV2-Mediated Gene Therapy for Choroideremia: The Alberta Experience

PURPOSE

To assess the safety of a recombinant adeno-associated viral vector expressing REP1 (rAAV2.REP1) in choroideremia subjects.

METHODS

Design: Phase I clinical trial.

PARTICIPANTS

Six adult male subjects, 30-42 years of age, with genetically confirmed choroideremia (CHM) were enrolled. The eye with the worse vision, for all subjects, received a single subfoveal injection of 0.1 mL rAAV2.REP1 containing 10¹¹ genome particles. Subjects were followed up for 2 years thereafter.

OUTCOME MEASURES

The primary outcome measure was safety, determined by the number of ocular and systemic adverse events assessed by ophthalmic examination, spectral-domain optical coherence tomography (SD-OCT), and short-wavelength autofluorescence (FAF). Secondary outcome measures were the change from baseline in best-corrected visual acuity (BCVA) in the treated eye compared to the untreated eye, changes in visual function using microperimetry, and the area of retinal pigment epithelium (RPE) preservation by FAF.

RESULTS

One subject had an 8-ETDRS-letter BCVA loss from baseline measured at 24 months, while 1 subject had a ≥15-letter BCVA gain. A similar improvement was noted in the untreated eye of another subject throughout the follow-up period. Microperimetry sensitivity showed no improvement or significant change up to 2 years after vector administration. The area of preserved RPE as measured by FAF was noted to decline at a similar rate between the treated and untreated eyes. One subject experienced a serious adverse event: a localized intraretinal immune response, resulting in marked decline in visual function and loss of SD-OCT outer retinal structures.

CONCLUSIONS

One serious adverse event was experienced in 6 subjects treated with a subfoveal injection of AAV2.REP1. The area of remaining functional RPE in the treated eye and untreated eye declined at the same rate over a 2-year period. Fundus autofluorescence area is a remarkably predictive biomarker and objective outcome measure for future studies of ocular gene therapy in CHM subjects.

Ability of the American College of Rheumatology 1987 criteria to predict rheumatoid arthritis in patients with early arthritis and classification of these patients two years later

OBJECTIVE

To determine how well the American College of Rheumatology (ACR; formerly, the American Rheumatism Association) 1987 classification criteria for rheumatoid arthritis (RA), when used at study inclusion in a cohort of 270 patients with early (<1 year) arthritis, predicted a diagnosis of RA 2 years later and how well they classified these patients at the end of the 2 years.

METHODS

Patients were evaluated during 1995-1997 at 7 hospitals in the Brittany region of France. Patients were evaluated at 6-month intervals until November 1999. The diagnosis made by a panel of 5 rheumatologists (P5R) after the last visit was used as the "gold standard." The ACR 1987 criteria for RA were applied prospectively, without taking into account the initial diagnosis.

RESULTS

At the last visit (mean +/- SD followup 29.1 +/- 11.8 months; median 30 months), the P5R diagnosed RA in 98 patients. At the last visit, classification by the ACR criteria was satisfactory, and the combination of an office-based rheumatologist's (OBR's) diagnosis of RA and fulfillment of the ACR criteria was sensitive (87%; 85 of 98 RA patients had both) and highly specific (99%; 170 of 172 non-RA patients did not have both). Application of the criteria at the first visit was of limited value for predicting a diagnosis of RA 2 years later.

CONCLUSION

After a 2-year followup, the ACR 1987 classification criteria used in combination with an OBR's diagnosis were effective in distinguishing patients with and without RA. The criteria were not useful for predicting RA in patients with arthritis onset within the previous year. Some patients who met the criteria at baseline and after 2 years did not have RA, suggesting that incorporating exclusion criteria may improve the performance of the ACR criteria when used without taking into account the diagnosis by a rheumatologist, particularly in early arthritis.

Plasma Diagnosis from Thermal Noise and Limits on Dust Flux or Mass in Comet Giacobini-Zinner

Thermal noise spectroscopy was used to measure the density and temperature of the main (cold) electron plasma population during 2 hours (1.5x10(5) kilometers perpendicular to the tail axis) around the point of closest approach of the International Cometary Explorer (ICE) to Comet Giacobini-Zinner. The time resolution was 18 seconds (370 kilometers) in the plasma tail and 54 seconds (1100 kilometers) elsewhere. Near the tail axis, the maximum plasma density was 670 per cubic centimeter and the temperature slightly above 1 electron volt. Away from the axis, the plasma density dropped to 100 per cubic centimeter (temperature, 2x 10(4) K) over 2000 kilometers, then decreased to 10 (1.5x 10(5)K) over 15,000 kilometers; outside that region (plasma tail), the density fluctuated between 10 and 30 per cubic centimeter and the temperature between 1x 10(5) and 4 x10(5) K. The relative density of the hot population rarely exceeded a few percent. The tail was highly asymmetrical and showed much structure. On the other antenna, shot noise was recorded from the plasma particle impacts on the spacecraft body. No evidence was found of grain impacts on the antennas or spacecraft in the plasma tail. This yields an upper limit for the dust flux or particle mass, indicating either fluxes or masses in the tail smaller than implied by the models or an anomalous grain structure. This seems to support earlier suggestions that these grains are featherlike. Outside the tail, and particularly near 10(5) kilometers from its axis, impulsive noises indicating plasma turbulence were observed.

Ulysses radio and plasma wave observations in the jupiter environment

The Unified Radio and Plasma Wave (URAP) experiment has produced new observations of the Jupiter environment, owing to the unique capabilities of the instrument and the traversal of high Jovian latitudes. Broad-band continuum radio emission from Jupiter and in situ plasma waves have proved valuable in delineating the magnetospheric boundaries. Simultaneous measurements of electric and magnetic wave fields have yielded new evidence of whistler-mode radiation within the magnetosphere. Observations of aurorallike hiss provided evidence of a Jovian cusp. The source direction and polarization capabilities of URAP have demonstrated that the outer region of the lo plasma torus supported at least five separate radio sources that reoccurred during successive rotations with a measurable corotation lag. Thermal noise measurements of the lo torus densities yielded values in the densest portion that are similar to models suggested on the basis of Voyager observations of 13 years ago. The URAP measurements also suggest complex beaming and polarization characteristics of Jovian radio components. In addition, a new class of kilometer-wavelength striated Jovian bursts has been observed.

Brain Dynamics Underlying Cognitive Flexibility Across the Lifespan

The neural mechanisms contributing to flexible cognition and behavior and how they change with development and aging are incompletely understood. The current study explored intrinsic brain dynamics across the lifespan using resting-state fMRI data (n = 601, 6-85 years) and examined the interactions between age and brain dynamics among three neurocognitive networks (midcingulo-insular network, M-CIN; medial frontoparietal network, M-FPN; and lateral frontoparietal network, L-FPN) in relation to behavioral measures of cognitive flexibility. Hierarchical multiple regression analysis revealed brain dynamics among a brain state characterized by co-activation of the L-FPN and M-FPN, and brain state transitions, moderated the relationship between quadratic effects of age and cognitive flexibility as measured by scores on the Delis-Kaplan Executive Function System (D-KEFS) test. Furthermore, simple slope analyses of significant interactions revealed children and older adults were more likely to exhibit brain dynamic patterns associated with poorer cognitive flexibility compared with younger adults. Our findings link changes in cognitive flexibility observed with age with the underlying brain dynamics supporting these changes. Preventative and intervention measures should prioritize targeting these networks with cognitive flexibility training to promote optimal outcomes across the lifespan.

Ulysses Radio and Plasma Wave Observations at High Southern Heliographic Latitudes

Ulysses spacecraft radio and plasma wave observations indicate that some variations in the intensity and occurrence rate of electric and magnetic wave events are functions of heliographic latitude, distance from the sun, and phase of the solar cycle. At high heliographic latitudes, solartype Ill radio emissions did not descend to the local plasma frequency, in contrast to the emission frequencies of some bursts observed in the ecliptic. Short-duration bursts of electrostatic and electromagnetic waves were often found in association with depressions in magnetic field amplitude, known as magnetic holes. Extensive wave activity observed in magnetic clouds may exist because of unusually large electron-ion temperature ratios. The lower number of intense in situ wave events at high latitudes was likely due to the decreased variability of the high- latitude solar wind.

Evoked and intrinsic brain network dynamics in children with autism spectrum disorder

OBJECTIVE

Brain dynamics underlie flexible cognition and behavior, yet little is known regarding this relationship in autism spectrum disorder (ASD). We examined time-varying changes in functional co-activation patterns (CAPs) across rest and task-evoked brain states to characterize differences between children with ASD and typically developing (TD) children and identify relationships with severity of social behaviors and restricted and repetitive behaviors.

METHOD

17 children with ASD and 27 TD children ages 7-12 completed a resting-state fMRI scan and four runs of a non-cued attention switching task. Metrics indexing brain dynamics were generated from dynamic CAPs computed across three major large-scale brain networks: midcingulo-insular (M-CIN), medial frontoparietal (M-FPN), and lateral frontoparietal (L-FPN).

RESULTS

Five time-varying CAPs representing dynamic co-activations among network nodes were identified across rest and task fMRI datasets. Significant Diagnosis × Condition interactions were observed for the dwell time of CAP 3, representing co-activation between nodes of the M-CIN and L-FPN, and the frequency of CAP 1, representing co-activation between nodes of the L-FPN. A significant brain-behavior association between dwell time of CAP 5, representing co-activation between nodes of the M-FPN, and social abilities was also observed across both groups of children.

CONCLUSION

Analysis of brain co-activation patterns reveals altered dynamics among three core networks in children with ASD, particularly evident during later stages of an attention task. Dimensional analyses demonstrating relationships between M-FPN dwell time and social abilities suggest that metrics of brain dynamics may index individual differences in social cognition and behavior.

The Alberta Newborn Screening Approach for Sickle Cell Disease: The Advantages of Molecular Testing

Sickle cell disease (SCD), a group of inherited red blood cell (RBC) disorders caused by pathogenic variants in the beta-globin gene (HBB), can cause lifelong disabilities and/or early mortality. If diagnosed early, preventative measures significantly reduce adverse outcomes related to SCD. In Alberta, Canada, SCD was added to the newborn screening (NBS) panel in April 2019. The primary conditions screened for are sickle cell anemia (HbS/S), HbS/C disease, and HbS/β thalassemia. In this study, we retrospectively analyzed the first 19 months of SCD screening performance, as well as described our approach for screening of infants that have received a red blood cell transfusion prior to collection of NBS specimen. Hemoglobins eluted from dried blood spots were analyzed using the Bio-Rad™ VARIANT nbs analyzer (Bio-Rad Laboratories, Inc., Hercules, CA, USA). Targeted sequencing of HBB was performed concurrently in samples from all transfused infants. During the period of this study, 43 of 80,314 screened infants received a positive NBS result for SCD, and of these, 34 were confirmed by diagnostic testing, suggesting a local SCD incidence of 1:2400 births. There were 608 infants with sickle cell trait, resulting in a carrier frequency of 1:130. Over 98% of non-transfused infants received their NBS results within 10 days of age. Most of the 188 transfused infants and 2 infants who received intrauterine transfusions received their final SCD screen results within 21 ± 10 d of birth. Our SCD screening algorithm enables detection of affected newborns on the initial NBS specimen, independent of the reported blood transfusion status.

Electrophilic reactivity of the Busulfan metabolite, EdAG, towards cellular thiols and inhibition of human thioredoxin-1

Busulfan is an alkylating agent used in chemotherapy conditioning regimens prior to hematopoietic stem cell transplantation (HSCT). However, its administration is associated with a great risk of adverse toxicities, which have been historically attributed to busulfan's mechanism of non-specific DNA alkylation. A phase II generated metabolite of busulfan, EdAG (γ-glutamyldehydroalanylglycine), is a dehydroalanine analog of glutathione (GSH) with an electrophilic moiety, suggesting it may bind to proteins and disrupt biological function. However, EdAG's reactions with common cellular thiols such as glutathione (GSH) and l-cysteine are understudied, along with possible inhibition of glutathionylation-dependent enzymes (with active site cysteine residues). We established a physiologically-relevant in vitro model to readily measure thiol loss over time. Using this model, we compared the apparent rates of thiol depletion in the presence of EdAG or arecoline, a toxic constituent of the areca (betel) nut and known GSH depletor. Simulated kinetic modeling revealed that the mean (±SE) alpha (α) second order rate constants describing GSH and l-cysteine depletion in the presence of EdAG were 0.00522 (0.00845) μM^-1∙min^-1 and 0.0207 (0.00721) μM^-1∙min^-1, respectively; in the presence of arecoline, the apparent rates of depletion were 0.0619 (0.009) μM^-1∙min^-1 and 0.2834 (0.0637) μM^-1∙min^-1 for GSH and l-cysteine, respectively. Under these experimental conditions, we conclude that EdAG was a weaker electrophile than arecoline. Arecoline and EdAG both depleted apparent l-cysteine concentrations to a much greater extent than GSH, approximately 4.58-fold and 3.97-fold change greater, respectively. EdAG modestly inhibited (∼20%) the human thioredoxin-1 (hTrx-1) catalyzed reduction of insulin with a mean IC₅₀ of 93 μM [95% CI: 78.6-110 μM). In summary, EdAG's ability to spontaneously react with endogenous thiols and inhibit hTrx-1 are potentially biochemically relevant in humans. These findings continue to support the growing concept that EdAG, an underrecognized phase II metabolite of busulfan, plays a role in untoward cellular toxicities during busulfan pharmacotherapy.

Minors are the most affected by Chlamydia trachomatis in Reunion Island: A cross-sectional study, 2017-2018

OBJECTIVES

To determine the prevalence of Chlamydia trachomatis (CT) in the population screened at sexually transmitted infection (STI) clinics on Reunion Island and to identify risk factors for CT infection.

PATIENTS AND METHODS

This cross-sectional multicenter study was conducted in 2017-2018. Data were obtained from self-administered questionnaires and multiplex PCR tests.

RESULTS

The overall prevalence of CT in the screened population was 8.6% (95% CI 7.7-9.5%). The prevalence of urogenital CT was highest in women under 18 (13.2%, 95% CI 9.3-18.1%) and in men who have sex with men under 18 (13.3%, 95% CI 1.6-48.2%). Risk factors associated with CT infection in multivariate analysis were: female gender, being born in Reunion Island, having had a large number of sexual partners in the past year, and being co-infected with another STI.

CONCLUSIONS

The prevalence of CT in the screened population is higher in Reunion Island than in mainland France, especially in minors. Prevention campaigns targeting minors should be strengthened.

Whole exome sequencing reveals putatively novel associations in retinopathies and drusen formation

Inherited retinal dystrophies (IRDs) affect 1 in 3000 individuals worldwide and are genetically heterogeneous, with over 270 identified genes and loci; however, there are still many identified disorders with no current genetic etiology. Whole exome sequencing (WES) provides a hypothesis-free first examination of IRD patients in either a clinical or research setting to identify the genetic cause of disease. We present a study of IRD in ten families from Alberta, Canada, through the lens of novel gene discovery. We identify the genetic etiology of IRDs in three of the families to be variants in known disease-associated genes, previously missed by clinical investigations. In addition, we identify two potentially novel associations: LRP1 in early-onset drusen formation and UBE2U in a multi-system condition presenting with retinoschisis, cataracts, learning disabilities, and developmental delay. We also describe interesting results in our unsolved cases to provide further information to other investigators of these blinding conditions.

Sickle cell trait newborn screen results: disclosure and management

This study aims to evaluate the notification process of sickle cell trait (SCT) identified by newborn screening in Alberta. On April 1, 2019, Alberta began newborn screening for sickle cell disease (SCD) and elected to report sickle cell trait (SCT). For 1 year, healthcare providers (HCPs) were sent a questionnaire which addressed the perceived importance of disclosing the SCT results, whether HCPs felt competent in disclosing the result, knowledge of available resources, and comfort with coordinating and interpreting testing for the newborn's parents. As a control, we collected data from HCPs receiving positive cystic fibrosis (CF) newborn screen results. A total of 107 out of 203 SCT questionnaires were returned and 41 of 66 CF questionnaires were returned. Respondents felt it was important that the results be shared with families (98% and 100%, respectively). Most respondents felt competent (SCT: 95%; CF: 85%), and willing to disclose the result to the family (SCT: 92%; CF: 88%). Fewer respondents were comfortable interpreting the results (SCT: 70%; CF: 51%)), and willing to arrange parental testing (SCT: 61%; CF: 59%). Family practitioners were significantly more willing to arrange SCT parental testing (88%) compared to pediatricians (40%) (OR = 5.3; CI 1.9, 15.4; p < 0.001). HCP comments revealed two themes: referral to another HCP for follow-up and identification of the primary HCP. Results support this disclosure process, and HCPs felt comfortable following up with SCT newborn screen results. The study identified challenges such as pediatricians being less comfortable ordering parental testing and the ordering HCP not always being the primary care provider.

In vitro hydrolysis of areca nut xenobiotics in human liver

Areca nut (AN) is a substance of abuse consumed by millions worldwide, in spite of established oral and systemic toxicities associated with its use. Previous research demonstrates methyl ester alkaloids in the AN, such as arecoline and guvacoline, exhibit mood-altering and toxicological effects. Nonetheless, their metabolism has not been fully elucidated in humans. In the present study, an HPLC-UV bioanalytical method was developed to evaluate the hydrolytic kinetics and clearance rates of arecoline and guvacoline in human liver microsomes (HLM) and cytosol (HLC). The bioassay was capable of quantifying arecoline and guvacoline (and carboxylate metabolites arecaidine and guvacine, respectively) with good sensitivity, accuracy, and precision. Kinetics of arecoline and guvacoline hydrolysis best followed the Michaelis-Menten model. Apparent intrinsic clearance (Clint.in vivo) of arecoline was 57.8 ml/min/kg in HLM and 11.6 mL/min/kg in HLC, a 5-fold difference. Unexpectedly, guvacoline was dramatically less hydrolyzed than arecoline in both HLM and HLC, with Clint.in vivo estimates of 0.654 ml/min/kg and 0.466 ml/min/kg, respectively. These results demonstrate, for the first time, arecoline undergoes significant hydrolysis with high clearance rates in the liver. Furthermore, differential tissue metabolic rates and utilization of specific esterase inhibitors unequivocally demonstrated arecoline is a substrate for CES1 and not CES2.

Secondary Reporting of G6PD Deficiency on Newborn Screening

In April 2019, the Alberta Newborn Screening Program expanded to include screening for classic galactosemia using a two-tier screening approach. This approach secondarily identifies infants with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The goals of this study were (i) to evaluate the performance of a two-tier galactosemia screening protocol, (ii) to explore the impact on and acceptability to families of reporting G6PD deficiency as a secondary finding, and (iii) assess the communication and follow-up process for positive G6PD deficiency screening results. The two-tiered galactosemia approach increased the positive predictive value (PPV) for galactosemia from 8% to 79%. An additional 119 positive newborn screen results were reported for G6PD deficiency with a PPV of 92%. The results show that there may be utility in reporting G6PD deficiency results. Most parents who participated in the study reported having some residual worry around the unexpected diagnosis; however, all thought it was helpful to know of their child's diagnosis of G6PD deficiency. Finally, the communication process for reporting G6PD deficiency newborn screen results was determined to result in appropriate follow up of infants.

Ability of hand radiographs to predict a further diagnosis of rheumatoid arthritis in patients with early arthritis

OBJECTIVE

To evaluate the ability of hand radiographs collected at study inclusion to predict a diagnosis of rheumatoid arthritis (RA) 2 years later, in a cohort of patients with early arthritis.

METHODS

We evaluated 270 patients with arthritis of less than one year duration. At the first visit, all patients underwent a standardized evaluation including laboratory tests and radiographs. Followup was 30+/-11.3 mo. The hand radiographs were read by observers blinded to patient data who looked for item 7 of the 1987 ACR criteria for RA and used Sharp's method to score erosions and joint space narrowing.

RESULTS

The kappa coefficient for ACR item 7 was < 0.65 for bony decalcification and > 0.8 for erosions. Intra and interobserver correlation coefficients for Sharp score ranged from 0.90 to 0.95. The "erosion" component of ACR item 7 was more specific than the full item 7 (96% versus 87.5%; p = 0.02). Sharp erosion score was not better than the erosion component of item 7 (sensitivity 17%; specificity 96%).

CONCLUSION

Regardless of the criterion used, hand radiographs were of limited value to predict which patients would be considered as having RA 2 years later. Diagnostic performance was similar for the "erosions" component of the 1987 ACR item 7 and for Sharp erosion score. The full 1987 ACR item 7 (erosions or bony decalcification) performed less well.