Evaluation of cytosine base editing and adenine base editing as a potential treatment for alpha-1 antitrypsin deficiency.

Alpha-1 antitrypsin deficiency (AATD) is a rare autosomal codominant disease caused by mutations within the SERPINA1 gene. The most prevalent variant in patients is PiZ SERPINA1, containing a single G > A transition mutation. PiZ alpha-1 antitrypsin (AAT) is prone to misfolding, leading to the accumulation of toxic aggregates within hepatocytes. In addition, the abnormally low level of AAT secreted into circulation provides insufficient inhibition of neutrophil elastase within the lungs, eventually causing emphysema. Cytosine and adenine base editors enable the programmable conversion of C⋅G to T⋅A and A⋅T to G⋅C base pairs, respectively. In this study, two different base editing approaches were developed: use of a cytosine base editor to install a compensatory mutation (p.Met374Ile) and use of an adenine base editor to mediate the correction of the pathogenic PiZ mutation. After treatment with lipid nanoparticles formulated with base editing reagents, PiZ-transgenic mice exhibited durable editing of SERPINA1 in the liver, increased serum AAT, and improved liver histology. These results indicate that base editing has the potential to address both lung and liver disease in AATD.

Patient Trajectories Among Persons Hospitalized for COVID-19 : A Cohort Study.

BACKGROUND: Risk factors for progression of coronavirus disease 2019 (COVID-19) to severe disease or death are underexplored in U.S. cohorts. OBJECTIVE: To determine the factors on hospital admission that are predictive of severe disease or death from COVID-19. DESIGN: Retrospective cohort analysis. SETTING: Five hospitals in the Maryland and Washington, DC, area. PATIENTS: 832 consecutive COVID-19 admissions from 4 March to 24 April 2020, with follow-up through 27 June 2020. MEASUREMENTS: Patient trajectories and outcomes, categorized by using the World Health Organization COVID-19 disease severity scale. Primary outcomes were death and a composite of severe disease or death. RESULTS: Median patient age was 64 years (range, 1 to 108 years); 47% were women, 40% were Black, 16% were Latinx, and 21% were nursing home residents. Among all patients, 131 (16%) died and 694 (83%) were discharged (523 [63%] had mild to moderate disease and 171 [20%] had severe disease). Of deaths, 66 (50%) were nursing home residents. Of 787 patients admitted with mild to moderate disease, 302 (38%) progressed to severe disease or death: 181 (60%) by day 2 and 238 (79%) by day 4. Patients had markedly different probabilities of disease progression on the basis of age, nursing home residence, comorbid conditions, obesity, respiratory symptoms, respiratory rate, fever, absolute lymphocyte count, hypoalbuminemia, troponin level, and C-reactive protein level and the interactions among these factors. Using only factors present on admission, a model to predict in-hospital disease progression had an area under the curve of 0.85, 0.79, and 0.79 at days 2, 4, and 7, respectively. LIMITATION: The study was done in a single health care system. CONCLUSION: A combination of demographic and clinical variables is strongly associated with severe COVID-19 disease or death and their early onset. The COVID-19 Inpatient Risk Calculator (CIRC), using factors present on admission, can inform clinical and resource allocation decisions. PRIMARY FUNDING SOURCE: Hopkins inHealth and COVID-19 Administrative Supplement for the HHS Region 3 Treatment Center from the Office of the Assistant Secretary for Preparedness and Response.

Functionalized lipid-like nanoparticles for in vivo mRNA delivery and base editing.

Messenger RNA (mRNA) therapeutics have been explored to treat various genetic disorders. Lipid-derived nanomaterials are currently one of the most promising biomaterials that mediate effective mRNA delivery. However, efficiency and safety of this nanomaterial-based mRNA delivery remains a challenge for clinical applications. Here, we constructed a series of lipid-like nanomaterials (LLNs), named functionalized TT derivatives (FTT), for mRNA-based therapeutic applications in vivo. After screenings on the materials, we identified FTT5 as a lead material for efficient delivery of long mRNAs, such as human factor VIII (hFVIII) mRNA (~4.5 kb) for expression of hFVIII protein in hemophilia A mice. Moreover, FTT5 LLNs demonstrated high percentage of base editing on PCSK9 in vivo at a low dose of base editor mRNA (~5.5 kb) and single guide RNA. Consequently, FTT nanomaterials merit further development for mRNA-based therapy.

Hip Range of Motion: Which Plane of Motion Is More Predictive of Lower Extremity Injury in Elite Soccer Players? A Prospective Study.

The objective of this study was to determine which plane of hip motion (rotational or sagittal) is more predictive of lower extremity (LE) injury in elite soccer players. A total of 69 athletes (43 professional and 26 collegiate) were examined (mean age, 22.6 years). Bilateral hip internal rotation (IR), external rotation, extension, and flexion measurements were taken along with the modified Thomas test during preseason physicals. There were 42 LE injuries (injury rate 3.74/1000 athlete exposures). Mean IR was 25.2. and 29.9° for injured versus noninjured extremities, respectively (p = .009). There was a significant association between decreased IR (categorized as IR < 28°) and incidence of ipsilateral LE injury (p = .042). Extremities with IR < 28° were 2.81 times more likely to sustain a LE injury (95% CI, 1.15.6.84; p = .023). With a utilitarian focus, the current study has identified a measurement of decreased hip IR with potential for substantial clinical value in collegiate and professional soccer players. (Journal of Surgical Orthopaedic Advances 28(3):201-208, 2019).

Arthroscopic knotless rotator cuff repair: Factors associated with construct selection and recent trends from a manual review of 1617 cases.

PURPOSE: Our aim was to identify predictors of construct selection and recent trends for arthroscopic knotless rotator cuff repair (RCR). METHODS: A manual review of 1617 operative reports was performed. RESULTS: A medium-sized tear had a threefold increase in odds of single row (SR) knotless repair (OR, 6.91; p = 0.009) versus SR knotted (OR, 3.05; p = 0.003). Generalist orthopaedic surgeons were 79% less likely to perform SR knotless repairs versus sports medicine trained specialists (p < 0.001). CONCLUSION: There was a significant increase from 2009 to 2016 in SR knotless and double row medial row knotless constructs contrasting the declining use of the SR knotted technique.

A Single Administration of CRISPR/Cas9 Lipid Nanoparticles Achieves Robust and Persistent In Vivo Genome Editing.

The development of clinically viable delivery methods presents one of the greatest challenges in the therapeutic application of CRISPR/Cas9 mediated genome editing. Here, we report the development of a lipid nanoparticle (LNP)-mediated delivery system that, with a single administration, enabled significant editing of the mouse transthyretin (Ttr) gene in the liver, with a >97% reduction in serum protein levels that persisted for at least 12 months. These results were achieved with an LNP delivery system that was biodegradable and well tolerated. The LNP delivery system was combined with a sgRNA having a chemical modification pattern that was important for high levels of in vivo activity. The formulation was similarly effective in a rat model. Our work demonstrates that this LNP system can deliver CRISPR/Cas9 components to achieve clinically relevant levels of in vivo genome editing with a concomitant reduction of TTR serum protein, highlighting the potential of this system as an effective genome editing platform.

Knockdown of ß-catenin with dicer-substrate siRNAs reduces liver tumor burden in vivo.

Despite progress in identifying molecular drivers of cancer, it has been difficult to translate this knowledge into new therapies, because many of the causal proteins cannot be inhibited by conventional small molecule therapeutics. RNA interference (RNAi), which uses small RNAs to inhibit gene expression, provides a promising alternative to reach traditionally undruggable protein targets by shutting off their expression at the messenger RNA (mRNA) level. Challenges for realizing the potential of RNAi have included identifying the appropriate genes to target and achieving sufficient knockdown in tumors. We have developed high-potency Dicer-substrate short-interfering RNAs (DsiRNAs) targeting ß-catenin and delivered these in vivo using lipid nanoparticles, resulting in significant reduction of ß-catenin expression in liver cancer models. Reduction of ß-catenin strongly reduced tumor burden, alone or in combination with sorafenib and as effectively as DsiRNAs that target mitotic genes such as PLK1 and KIF11. ß-catenin knockdown also strongly reduced the expression of ß-catenin-regulated genes, including MYC, providing a potential mechanism for tumor inhibition. These results validate ß-catenin as a target for liver cancer therapy and demonstrate the promise of RNAi in general and DsiRNAs in particular for reaching traditionally undruggable cancer targets.