Low copy CRISPR-Cas13d mitigates collateral RNA cleavage.

While CRISPR-Cas13 systems excel in accurately targeting RNA, the potential for collateral RNA degradation poses a concern for therapeutic applications and limits broader adoption for transcriptome perturbations. We evaluate the extent to which collateral RNA cleavage occurs when Rfx Cas13d is delivered via plasmid transfection or lentiviral transduction and find that collateral activity only occurs with high levels of Rfx Cas13d expression. Using transcriptome-scale and combinatorial CRISPR pooled screens in cell lines with low-copy Rfx Cas13d, we find high on-target knockdown, without extensive collateral activity regardless of the expression level of the target gene. In contrast, transfection of Rfx Cas13d, which yields higher nuclease expression, results in collateral RNA degradation. Further, our analysis of a high-fidelity Cas13 variant uncovers a marked decrease in on-target efficiency, suggesting that its reduced collateral activity may be due to an overall diminished nuclease capability.

Efficacy and safety of guselkumab in patients with active psoriatic arthritis who had inadequate efficacy and/or intolerance to one prior tumor necrosis factor inhibitor: study protocol for SOLSTICE, a phase 3B, multicenter, randomized, double-blind, placebo-controlled study.

BACKGROUND: Tumor necrosis factor inhibitors (TNFi) are frequently chosen as the first biologic for patients with psoriatic arthritis (PsA). Given that many patients with PsA are TNFi inadequate responders (TNF-IR; either inadequate efficacy or intolerance), treatments utilizing alternative mechanisms of action are needed. In phase 3 studies, the fully human interleukin (IL)-23p19 subunit-inhibitor, guselkumab, was efficacious in patients with active PsA, including TNFi-IR. Efficacy was generally consistent between TNFi-naïve and TNFi-experienced cohorts; however, in the latter, higher response rates have been observed with the Q4W dosing regimen relative to the Q8W dosing regimen for some endpoints, suggesting the need to evaluate whether more frequent dosing may provide an incremental clinical benefit for TNFi-IR patients. METHODS: The phase 3b SOLSTICE study will assess guselkumab efficacy and safety in TNFi-IR PsA patients. Eligibility criteria include a PsA diagnosis for ≥ 6 months; active disease (≥ 3 swollen, ≥ 3 tender joints, C-reactive protein ≥ 0.3 mg/dL); and inadequate efficacy with, and/or intolerance to, one prior TNFi. Participants will be randomized 1:1:1 to guselkumab Q4W or Q8W or placebo→guselkumab Q4W (at Week 24). The primary endpoint is the proportion of patients achieving ≥ 20% improvement in the American College of Rheumatology criteria (ACR20) at Week 24. Major secondary endpoints include ACR50, ACR70; an Investigator's Global Assessment (IGA) of psoriasis score of 0/1 plus ≥ 2-grade reduction and ≥ 90% improvement in Psoriasis Area and Severity Index (both among patients with ≥ 3% body surface area affected by psoriasis and baseline IGA ≥ 2); minimal/very low disease activity; and changes from baseline in Health Assessment Questionnaire-Disability Index, the 36-item Short-Form Health Survey Physical Component Summary, and Functional Assessment of Chronic Illness Therapy-Fatigue scores. The target sample size (N = 450) is estimated to provide > 90% power in detecting differences between each guselkumab group and the placebo group for the primary endpoint assuming a 2-sided α = 0.05. Cochran-Mantel-Haenszel testing and analyses of covariance will be used to compare efficacy for binary and continuous endpoints, respectively. DISCUSSION: Findings from the phase 3b SOLSTICE study, the design of which was informed by results from previously conducted phase 3 studies, is expected to provide important efficacy and safety information on guselkumab therapy in TNFi-IR patients with PsA. TRIAL REGISTRATION: This trial was registered at ClinicalTrials.gov, NCT04936308, on 23 June 2021.

A clinical review of structural damage in psoriatic arthritis for dermatologists: From pathogenesis to ongoing controversies.

Psoriatic arthritis (PsA) is a chronic inflammatory disease that often goes unrecognized in patients with psoriasis. As a result, patients may develop significant structural damage before diagnosis and initiation of adequate treatment. Dermatologists are in an unique position to identify early signs and symptoms of PsA. Here, we briefly review the pathogenesis of PsA, differences in PsA presentation within real-world dermatology practice versus rheumatology clinical trials, and imaging modalities that can be used to assess structural damage. We then discuss several ongoing controversies related to prediction, assessment, and treatment of PsA-related structural damage. Debated questions include the following: (1) Does subclinical enthesitis predict progression from psoriasis to PsA?, (2) Does methotrexate inhibit progression of structural damage?, (3) Does structural damage correlate with clinical disease activity?, and (4) Can progression from psoriasis to PsA be prevented? Evidence presented herein suggests that dermatologists, together with rheumatologists, can play important roles in the early diagnosis and treatment of PsA, thereby potentially preventing irreversible structural damage.

Location-Specific Hematoma Volume Cutoff and Clinical Outcomes in Intracerebral Hemorrhage.

BACKGROUND: Major intracerebral hemorrhage (ICH) trials have largely been unable to demonstrate therapeutic benefit in improving functional outcomes. This may be partly due to the heterogeneity of ICH outcomes based on their location, where a small strategic ICH could be debilitating, thus confounding therapeutic effects. We aimed to determine the ideal hematoma volume cutoff for different ICH locations in predicting ICH outcomes. METHODS: We retrospectively analyzed consecutive ICH patients enrolled in the University of Hong Kong prospective stroke registry from January 2011 to December 2018. Patients with premorbid modified Rankin Scale score >2 or who underwent neurosurgical intervention were excluded. ICH volume cutoff, sensitivity, and specificity in predicting respective 6-month neurological outcomes (good [modified Rankin Scale score 0-2], poor [modified Rankin Scale score 4-6], and mortality) for specific ICH locations were determined using receiver operating characteristic curves. Separate multivariate logistic regression models were also conducted for each location-specific volume cutoff to determine whether these cutoffs were independently associated with respective outcomes. RESULTS: Among 533 ICHs, the volume cutoff for good outcome according to ICH location was 40.5 mL for lobar, 32.5 mL for putamen/external capsule, 5.5 mL for internal capsule/globus pallidus, 6.5 mL for thalamus, 17 mL for cerebellum, and 3 mL for brainstem. ICH smaller than the cutoff for all supratentorial sites had higher odds of good outcomes (all P<0.05). Volumes exceeding 48 mL for lobar, 41 mL for putamen/external capsule, 6 mL for internal capsule/globus pallidus, 9.5 mL for thalamus, 22 mL for cerebellum, and 7.5 mL for brainstem were at greater risk of poor outcomes (all P<0.05). Mortality risks were significantly higher for volumes that exceeded 89.5 mL for lobar, 42 mL for putamen/external capsule, and 21 mL for internal capsule/globus pallidus (all P<0.001). All receiver operating characteristic models for location-specific cutoffs had good discriminant values (area under the curve >0.8), except in predicting good outcome for cerebellum. CONCLUSIONS: ICH outcomes differed with location-specific hematoma size. Location-specific volume cutoff should be considered in patient selection for ICH trials.

Importance of Control Groups for Evaluating Long-Term Behavioral and Cognitive Outcomes of Controlled Cortical Impact in Immature Rats.

Therapies are limited for pediatric traumatic brain injury (TBI), especially for the very young who can experience long-term consequences to learning, memory, and social behavior. Animal models of pediatric TBI have yielded mechanistic insights, but demonstration of clinically relevant long-term behavioral and/or cognitive deficits has been challenging. We characterized short- and long-term outcomes in a controlled cortical impact (CCI) model of pediatric TBI using a panel of tests between 2 weeks and ∼4 months after injury. Male rats with CCI at postnatal Day (PND) 10 were compared with three control groups: Naïve, Anesthesia, and Craniotomy. Motor testing (PND 25-33), novel object recognition (NOR; PND 40-50), and multiple tasks in water maze (WM; PND 65-100) were followed by social interaction tests (PND 120-140). Anesthesia rats performed the same as Naïve rats in all tasks. TBI rats, when compared with Naïve controls, had functional impairments across most tests studied. The most sensitive cognitive processes affected by TBI included those that required fast one-trial learning (NOR, WM), flexibility of acquired memory traces (reversals in WM), response strategies (WM), or recognition memory in the setting of reciprocal social interactions. Both TBI and Craniotomy groups demonstrated increased rates of decision making across several WM tasks, suggesting disinhibition of motor responses. When the TBI group was compared with the Craniotomy group, however, deficits were detected in a limited number of outcomes. The latter included learning speed (WM), cognitive flexibility (WM), and social recognition memory. Notably, effects of craniotomy, when compared with Naïve controls, spanned across multiple tasks, and in some tasks, could reach the effect sizes observed in TBI. These results highlight the importance of appropriate control groups in pediatric CCI models. In addition, the study demonstrates the high sensitivity of comprehensive cognitive testing to detect long-term effects of early-age craniotomy and TBI and provides a template for future testing of experimental therapies.

Visual-stress-related cortical excitability as a prospective marker for symptoms of depression and anxiety in young people.

Visual stress is thought to reflect cortical excitability and has been associated with many neurological, neuropsychiatric, and neurodevelopmental conditions. However, its relationships with symptoms of depression and anxiety have not yet been elucidated. We conducted two separate studies to first examine visual stress in a longitudinal community sample of 104 participants (aged 12-24) in association with prospective symptoms of depression, anxiety, and distress after 3 months, and subsequently in a cross-sectional epidemiological sample of 530 participants (aged 15-24) to validate its associations with current mood and distress symptoms. The Pattern Glare Test was used to examine visual stress to three grating patterns with the spatial frequencies (SF) of 0.3, 2.3, and 9.4 cycles per degree (cpd). Other known factors of mental health, including functioning, as well as resilience, hopelessness, and loneliness, were also assessed at baseline. In both studies, we showed that perceptual distortions were highest toward the pattern with mid-SF (2.3 cpd). Multiple linear regression analyses revealed that greater visual stress was significantly associated with not only baseline but also 3-month symptom outcomes, even when accounting for age, years of education, days of no functioning, resilience, hopelessness, and loneliness. Our findings suggest the importance of visual stress in understanding and predicting poor mental health outcomes. As mental health can lead to far-reaching consequences that extend to adulthood, our findings may inform state-of-the-art innovative strategies for the prediction of poor mental health outcomes and suggest visual stress as a potential marker for early risk detection among young people.

Photocrosslinked Bioreducible Polymeric Nanoparticles for Enhanced Systemic siRNA Delivery as Cancer Therapy.

Clinical translation of polymer-based nanocarriers for systemic delivery of RNA has been limited due to poor colloidal stability in the blood stream and intracellular delivery of the RNA to the cytosol. To address these limitations, this study reports a new strategy incorporating photocrosslinking of bioreducible nanoparticles for improved stability extracellularly and rapid release of RNA intracellularly. In this design, the polymeric nanocarriers contain ester bonds for hydrolytic degradation and disulfide bonds for environmentally triggered small interfering RNA (siRNA) release in the cytosol. These photocrosslinked bioreducible nanoparticles (XbNPs) have a shielded surface charge, reduced adsorption of serum proteins, and enable superior siRNA-mediated knockdown in both glioma and melanoma cells in high-serum conditions compared to non-crosslinked formulations. Mechanistically, XbNPs promote cellular uptake and the presence of secondary and tertiary amines enables efficient endosomal escape. Following systemic administration, XbNPs facilitate targeting of cancer cells and tissue-mediated siRNA delivery beyond the liver, unlike conventional nanoparticle-based delivery. These attributes of XbNPs facilitate robust siRNA-mediated knockdown in vivo in melanoma tumors colonized in the lungs following systemic administration. Thus, biodegradable polymeric nanoparticles, via photocrosslinking, demonstrate extended colloidal stability and efficient delivery of RNA therapeutics under physiological conditions, and thereby potentially advance systemic delivery technologies for nucleic acid-based therapeutics.

Migration, pathogens and the avian microbiome: A comparative study in sympatric migrants and residents.

Animals generally benefit from their gastrointestinal microbiome, but the factors that influence the composition and dynamics of their microbiota remain poorly understood. Studies of nonmodel host species can illuminate how microbiota and their hosts interact in natural environments. We investigated the role of migratory behaviour in shaping the gut microbiota of free-ranging barn swallows (Hirundo rustica) by studying co-occurring migrant and resident subspecies sampled during the autumn migration at a migratory bottleneck. We found that within-host microbial richness (α-diversity) was similar between migrant and resident microbial communities. In contrast, we found that microbial communities (ß-diversity) were significantly different between groups regarding both microbes present and their relative abundances. Compositional differences were found for 36 bacterial genera, with 27 exhibiting greater abundance in migrants and nine exhibiting greater abundance in residents. There was heightened abundance of Mycoplasma spp. and Corynebacterium spp. in migrants, a pattern shared by other studies of migratory species. Screens for key regional pathogens revealed that neither residents nor migrants carried avian influenza viruses and Newcastle disease virus, suggesting that the status of these diseases did not underlie observed differences in microbiome composition. Furthermore, the prevalence and abundance of Salmonella spp., as determined from microbiome data and cultural assays, were both low and similar across the groups. Overall, our results indicate that microbial composition differs between migratory and resident barn swallows, even when they are conspecific and sympatrically occurring. Differences in host origins (breeding sites) may result in microbial community divergence, and varied behaviours throughout the annual cycle (e.g., migration) could further differentiate compositional structure as it relates to functional needs.

Delays in Stroke Onset to Hospital Arrival Time During COVID-19.

BACKGROUND AND PURPOSE: The current coronavirus disease 2019 (COVID-19) pandemic represents a global public health crisis, disrupting emergency healthcare services. We determined whether COVID-19 has resulted in delays in stroke presentation and affected the delivery of acute stroke services in a comprehensive stroke center in Hong Kong. METHODS: We retrospectively reviewed all patients with transient ischemic attack and stroke admitted via the acute stroke pathway of Queen Mary Hospital, Hong Kong, during the first 60 days since the first diagnosed COVID-19 case in Hong Kong (COVID-19: January 23, 2020-March 24, 2020). We compared the stroke onset to hospital arrival (onset-to-door) time and timings of inpatient stroke pathways with patients admitted during the same period in 2019 (pre-COVID-19: January 23, 2019-March 24, 2019). RESULTS: Seventy-three patients in COVID-19 were compared with 89 patients in pre-COVID-19. There were no significant differences in age, sex, vascular risk factors, nor stroke severity between the 2 groups (P>0.05). The median stroke onset-to-door time was ≈1-hour longer in COVID-19 compared with pre-COVID-19 (154 versus 95 minutes, P=0.12), and the proportion of individuals with onset-to-door time within 4.5 hours was significantly lower (55% versus 72%, P=0.024). Significantly fewer cases of transient ischemic attack presented to the hospital during COVID-19 (4% versus 16%, P=0.016), despite no increase in referrals to the transient ischemic attack clinic. Inpatient stroke pathways and treatment time metrics nevertheless did not differ between the 2 groups (P>0.05 for all comparisons). CONCLUSIONS: During the early containment phase of COVID-19, we noted a prolongation in stroke onset to hospital arrival time and a significant reduction in individuals arriving at the hospital within 4.5 hours and presenting with transient ischemic attack. Public education about stroke should continue to be reinforced during the COVID-19 pandemic.

Engineered nanoparticles for systemic siRNA delivery to malignant brain tumours.

Improved delivery materials are needed to enable siRNA transport across biological barriers, including the blood-brain barrier (BBB), to treat diseases like brain cancer. We engineered bioreducible nanoparticles for systemic siRNA delivery to patient-derived glioblastoma cells in an orthotopic mouse tumor model. We first utilized a newly developed biomimetic in vitro model to evaluate and optimize the performance of the engineered bioreducible nanoparticles at crossing the brain microvascular endothelium. We performed transmission electron microscopy imaging which indicated that the engineered nanoparticles are able to cross the BBB endothelium via a vesicular mechanism. The nanoparticle formulation engineered to best cross the BBB model in vitro led to safe delivery across the BBB to the brain in vivo. The nanoparticles were internalized by human brain cancer cells, released siRNA to the cytosol via environmentally-triggered degradation, and gene silencing was obtained both in vitro and in vivo. This study opens new frontiers for the in vitro evaluation and engineering of nanomedicines for delivery to the brain, and reports a systemically administered biodegradable nanocarrier for oligonucleotide delivery to treat glioma.

Risk Factors and Post-Resection Independent Predictive Score for the Recurrence of Hepatitis B-Related Hepatocellular Carcinoma.

BACKGROUND: Independent risk factors associated with hepatitis B (HBV)-related hepatocellular carcinoma (HCC) after resection remains unknown. An accurate risk score for HCC recurrence is lacking. METHODS: We prospectively followed up 200 patients who underwent liver resection for HBV-related HCC for at least 2 years. Demographic, biochemical, tumor, virological and anti-viral treatment factors were analyzed to identify independent risk factors associated with recurrence after resection and a risk score for HCC recurrence formulated. RESULTS: Two hundred patients (80% male) who underwent liver resection for HBV-related HCC were recruited. The median time of recurrence was 184 weeks (IQR 52-207 weeks) for the entire cohort and 100 patients (50%) developed HCC recurrence. Stepwise Cox regression analysis identified that one-month post resection HBV DNA >20,000 IU/mL (p = 0.019; relative risk (RR) 1.67; 95% confidence interval (C.I.): 1.09-2.57), the presence of lymphovascular permeation (p<0.001; RR 2.69; 95% C.I.: 1.75-4.12), microsatellite lesions (p<0.001; RR 2.86; 95% C.I.: 1.82-4.51), and AFP >100ng/mL before resection (p = 0.021; RR 1.63; 95% C.I.: 1.08-2.47) were independently associated with HCC recurrence. Antiviral treatment before resection (p = 0.024; RR 0.1; 95% C.I.: 0.01-0.74) was independently associated with reduced risk of HCC recurrence. A post-resection independent predictive score (PRIPS) was derived and validated with sensitivity of 75.3% and 60.6% and specificity of 55.7% and 79.2%, to predict the 1- and 3-year risks for the HCC recurrence respectively with the hazard ratio of 2.71 (95% C.I.: 2.12-3.48; p<0.001). The AUC for the 1- and 3-year prediction were 0.675 (95% C.I.: 0.6-0.78) and 0.746 (95% C.I.: 0.69-0.82) respectively. CONCLUSION: Several tumor, virological and biochemical factors were associated with a higher cumulative risk of HCC recurrence after resection. PRIPS was derived for more accurate risk assessment. Regardless of the HBV DNA level, antiviral treatment should be given to patients before resection to reduce the risk of recurrence.