OxVent: Design and evaluation of a rapidly-manufactured Covid-19 ventilator.

BACKGROUND: The manufacturing of any standard mechanical ventilator cannot rapidly be upscaled to several thousand units per week, largely due to supply chain limitations. The aim of this study was to design, verify and perform a pre-clinical evaluation of a mechanical ventilator based on components not required for standard ventilators, and that met the specifications provided by the Medicines and Healthcare Products Regulatory Agency (MHRA) for rapidly-manufactured ventilator systems (RMVS). METHODS: The design utilises closed-loop negative feedback control, with real-time monitoring and alarms. Using a standard test lung, we determined the difference between delivered and target tidal volume (VT) at respiratory rates between 20 and 29 breaths per minute, and the ventilator's ability to deliver consistent VT during continuous operation for >14 days (RMVS specification). Additionally, four anaesthetised domestic pigs (3 male-1 female) were studied before and after lung injury to provide evidence of the ventilator's functionality, and ability to support spontaneous breathing. FINDINGS: Continuous operation lasted 23 days, when the greatest difference between delivered and target VT was 10% at inspiratory flow rates >825 mL/s. In the pre-clinical evaluation, the VT difference was -1 (-90 to 88) mL [mean (LoA)], and positive end-expiratory pressure (PEEP) difference was -2 (-8 to 4) cmH2O. VT delivery being triggered by pressures below PEEP demonstrated spontaneous ventilation support. INTERPRETATION: The mechanical ventilator presented meets the MHRA therapy standards for RMVS and, being based on largely available components, can be manufactured at scale. FUNDING: Work supported by Wellcome/EPSRC Centre for Medical Engineering,King's Together Fund and Oxford University.

Müller glia-derived PRSS56 is required to sustain ocular axial growth and prevent refractive error.

A mismatch between optical power and ocular axial length results in refractive errors. Uncorrected refractive errors constitute the most common cause of vision loss and second leading cause of blindness worldwide. Although the retina is known to play a critical role in regulating ocular growth and refractive development, the precise factors and mechanisms involved are poorly defined. We have previously identified a role for the secreted serine protease PRSS56 in ocular size determination and PRSS56 variants have been implicated in the etiology of both hyperopia and myopia, highlighting its importance in refractive development. Here, we use a combination of genetic mouse models to demonstrate that Prss56 mutations leading to reduced ocular size and hyperopia act via a loss of function mechanism. Using a conditional gene targeting strategy, we show that PRSS56 derived from Müller glia contributes to ocular growth, implicating a new retinal cell type in ocular size determination. Importantly, we demonstrate that persistent activity of PRSS56 is required during distinct developmental stages spanning the pre- and post-eye opening periods to ensure optimal ocular growth. Thus, our mouse data provide evidence for the existence of a molecule contributing to both the prenatal and postnatal stages of human ocular growth. Finally, we demonstrate that genetic inactivation of Prss56 rescues axial elongation in a mouse model of myopia caused by a null mutation in Egr1. Overall, our findings identify PRSS56 as a potential therapeutic target for modulating ocular growth aimed at preventing or slowing down myopia, which is reaching epidemic proportions.

Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci.

Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide. Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS. To further elucidate the genetic basis of XFS, we collected a global sample of XFS cases to refine the association at LOXL1, which previously showed inconsistent results across populations, and to identify new variants associated with XFS. We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10-14) through deep resequencing of XFS cases and controls from nine countries. A genome-wide association study (GWAS) of XFS cases and controls from 24 countries followed by replication in 18 countries identified seven genome-wide significant loci (P < 5 × 10-8). We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). These findings provide biological insights into the pathology of XFS and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.

Stability of Attitudes to the Ethical Issues Raised by the Return of Incidental Genomic Research Findings in Children: A Follow-Up Study.

OBJECTIVE: We explore the stability of parental attitudes to the ethical issues raised by the return of genomic research results. METHODS: A 19-item questionnaire was mailed to participants in a large genome research consortium 18 months following a baseline survey. We describe the stability of parental attitudes to (a) sharing of genomic research results, (b) endorsement of children in genomic research, (c) responsibilities of researchers, and (d) responsibilities to extended family. We also explore their experience in receiving results. RESULTS: Of 170 original participants, 154 (91%) responded. Most participants expressed positive rights to receive incidental genomic research findings (85%), including when ameliorative therapy was unknown (85%). Only 3% found it acceptable to delegate the decision to return results to an independent committee. Researchers, either with a parent (42%) or physician (17%), were felt to be responsible to convey research results to children when they reach adulthood. Most participants (74%) indicated that results should be shared with potentially affected extended family. These results are very similar to those of the baseline survey. All participants who received genomic results would do so again and reported actions similar to their expressed attitudes. CONCLUSIONS: The opinions of parents regarding genomic research remain stable over time. Guidelines on the return of results should incorporate these findings.

Attitudes of parents toward the return of targeted and incidental genomic research findings in children.

PURPOSE: We describe parental attitudes toward the return of targeted and incidental genomic research results in the setting of high-risk pediatric cancer and inherited childhood diseases. METHODS: A validated 36-item questionnaire was mailed to participants in three large-scale genome research consortia examining attitudes toward receipt of genomic research results and the influence of certainty, severity, and onset of the condition, in addition to responsibilities to extended family and provision of results even after death of the proband. RESULTS: Of the 563 participants who were sent questionnaires, 362 (64%) responded. Most of them stated a positive right to receive results related to the target condition (97%) or to incidental findings (86%); no difference was found in results between participants with cancer and those with orphan diseases. Furthermore, 92% indicated that genomic research for childhood-onset conditions should occur. The majority wanted incidental results predicting susceptibility even to untreatable fatal conditions (83%), to multiple conditions (87%), or to those with uncertain impact (70%). Most felt sibling genomic results showing serious conditions, whether treatable (93%) or not (88%), and/or results discovered after death of the proband should be shared with family (74%). CONCLUSION: Many parents of children in pediatric genomic research indicated a strong desire to receive a broader range of results than is described in consensus recommendations. Clear delineation of what will be offered should be established at the time of consent.

Human monogenic disorders - a source of novel drug targets.

The decrease in new drug applications and approvals over the past several years results from an underlying crisis in drug target identification and validation. Model organisms are being used to address this problem, in combination with novel approaches such as the International HapMap Project. What has been underappreciated is that discovery of new drug targets can also be revived by traditional Mendelian genetics. A large fraction of the human gene repertoire remains phenotypically uncharacterized, and is likely to encode many unanticipated and novel phenotypes that will be of interest to pharmaceutical and biotechnological drug developers.