Tunable loading of oligonucleotides with secondary structure on gold nanoparticles through a pH-driven method.

This paper describes how pH can be used to control covalent attachment of oligonucleotides with secondary structure on gold nanoparticles (AuNPs). The highest loading of thiolated nucleic acids occurred at low pH (pH = 1.7) due to reduced repulsion between the negatively charged oligonucleotides and the AuNP surface. The packing of oligonucleotides at low pH decreased (single-stranded ≫ duplex > quadruplex) as the spatial footprint of secondary structure increased. As the pH increased, a decrease in the number of DNA strands grafted to the AuNPs was observed. Notably, the loading density depended on the flexibility and spatial organization of the secondary structures at all pH conditions. At the lowest pH tested, circular dichroism analysis revealed that G-quadruplex aptamers underwent a structural change (from parallel to antiparallel or vice versa), although the biological activity of the aptamer-loaded AuNPs was still maintained. We anticipate that pH-tuning can result in quantitative loading of oligonucleotides on various types of AuNPs with different shapes and surface capping layers.

Biodistribution and in vivo toxicity of aptamer-loaded gold nanostars.

This paper reports an in vivo evaluation of toxicology and biodistribution of a highly anisotropic Au nanoconstruct composed of a gold nanostar (AuNS) core and a ligand shell of a G-quadruplex DNA aptamer AS1411 (Apt) supporting both targeting and therapy capabilities. We examined the toxicity of the nanoconstructs (Apt-AuNS) at four different injected concentrations. At the highest dose tested (48 mg/kg), maximal tolerated dose was not reached. Clinical pathology showed no apparent signs of acute toxicity. Interestingly, the nanoconstructs circulated longer in female rats compared to male rats. In two different tumor models, the biodistribution of Apt-AuNS, especially tumor accumulation, was different. Accumulation of Apt-AuNS was 5 times higher in invasive breast cancer tumors compared to fibrosarcoma tumors. These results provide insight on identifying a tumor model and nanoconstruct for in vivo studies, especially when an in vitro therapeutic response is observed in multiple cancer cell lines. From the clinical editor: This study investigated the toxicity and distribution of aptamer loaded gold nanostars in a rodent model of invasive breast cancer and fibrosarcoma. Acute toxicity was not identified even in the highest studied doses. Fivefold accumulation was demonstrated in the breast cancer model compared to the fibrosarcoma model. Studies like this are critically important in further clarifying the potential therapeutic use of these nanoconstructs, especially when ex vivo effects are clearly demonstrated.

Improved in vitro efficacy of gold nanoconstructs by increased loading of G-quadruplex aptamer.

This paper describes how in vitro efficacy of aptamer-loaded gold nanostars (Apt-AuNS) can be enhanced by the increased loading of a G-quadruplex homodimer AS1411 (Apt) on the AuNS surface. In a low pH buffer environment, the loading density of Apt on AuNS was increased up to 2.5 times that obtained using the conventional salt-aging process. These highly loaded AuNS nanoconstructs (*Apt-AuNS) were taken up in pancreatic cancer and fibrosarcoma cells ca. 2 times more and at faster rates compared to Apt-AuNS. When a similar number of AuNS carriers was internalized by the cancer cells, the amount of AS1411 delivered via *Apt-AuNS was effectively double that of Apt-AuNS, and *Apt-AuNS resulted in an average of 42% increase in cell death. These results suggest that increasing the loading density on AuNS could provide a simple means to improve uptake as well as in vitro efficacy of the nanoconstructs in cancer cells.

Variation in survival in patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation: A multi-institutional analysis of 594 consecutive patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation at 49 hospitals within 21 states.

OBJECTIVES: We reviewed 594 consecutive patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation at 49 hospitals within 21 states and examined patient characteristics, treatments, and variation in outcomes over the course of the pandemic. METHODS: A multi-institutional database was used to assess all patients with Coronavirus Disease 2019 cannulated for extracorporeal membrane oxygenation between March 17, 2020, and December 20, 2021, inclusive, and separated from ECMO on or prior to January 14, 2022. Descriptive analysis was stratified by 4 time categories: group A = March 2020 to June 2020, group B = July 2020 to December 2020, group C = January 2021 to June 2021, group D = July 2021 to December 2021. A Bayesian mixed-effects logistic regression was used to assess continuous trends in survival where time was operationalized as the number of days between each patient's cannulation and that of the first patient in March 2020, controlling for multiple variables and risk factors. RESULTS: At hospital discharge, of 594 patients, 221 survived (37.2%) and 373 died. Throughout the study, median age [interquartile range] declined (group A = 51.0 [41.0-60.0] years, group D = 39.0 [32.0-48.0] years, P < .001); median days between Coronavirus Disease 2019 diagnosis and intubation increased (group A = 4.0 [1.0-8.5], group D = 9.0 [5.0-14.5], P < .001); and use of medications (glucocorticoids, interleukin-6 blockers, antivirals, antimalarials) and convalescent plasma fluctuated significantly (all P < .05). Estimated odds of survival varied over the study period with a decline between April 1, 2020, and November 21, 2020 (odds ratio, 0.39, 95% credible interval, 0.18-0.87, probability of reduction in survival = 95.7%), improvement between November 21, 2020, and May 17, 2021 (odds ratio, 1.85, 95% credible interval, 0.86-4.09, probability of improvement = 93.4%), and decline between May 17, 2021, and December 1, 2021 (odds ratio, 0.49, 95% credible interval, 0.19-1.44, probability of decrease = 92.1%). CONCLUSIONS: Survival for patients with Coronavirus Disease 2019 supported with extracorporeal membrane oxygenation has fluctuated during the stages of the pandemic. Minimizing variability by adherence to best practices may refine the optimal use of extracorporeal membrane oxygenation in a pandemic response.

Clinical Course of Two Patients with COVID-19 Respiratory Failure After Administration of the Anticancer Small Molecule, RRx-001.

Two critically ill COVID-19 infected patients, who had exhausted all available treatment options, were treated with the small-molecule RRx-001 with subsequent improvement. RRx-001, a first-in-class small molecule with anti-inflammatory, vascular normalizing and macrophage-repolarizing properties, has been safely administered 300+ patients in clinical trials. This is the first report of RRx-001 treatment of COVID-19.

Lung epithelial and endothelial damage, loss of tissue repair, inhibition of fibrinolysis, and cellular senescence in fatal COVID-19.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is characterized by respiratory distress, multiorgan dysfunction, and, in some cases, death. The pathological mechanisms underlying COVID-19 respiratory distress and the interplay with aggravating risk factors have not been fully defined. Lung autopsy samples from 18 patients with fatal COVID-19, with symptom onset-to-death times ranging from 3 to 47 days, and antemortem plasma samples from 6 of these cases were evaluated using deep sequencing of SARS-CoV-2 RNA, multiplex plasma protein measurements, and pulmonary gene expression and imaging analyses. Prominent histopathological features in this case series included progressive diffuse alveolar damage with excessive thrombosis and late-onset pulmonary tissue and vascular remodeling. Acute damage at the alveolar-capillary barrier was characterized by the loss of surfactant protein expression with injury to alveolar epithelial cells, endothelial cells, respiratory epithelial basal cells, and defective tissue repair processes. Other key findings included impaired clot fibrinolysis with increased concentrations of plasma and lung plasminogen activator inhibitor-1 and modulation of cellular senescence markers, including p21 and sirtuin-1, in both lung epithelial and endothelial cells. Together, these findings further define the molecular pathological features underlying the pulmonary response to SARS-CoV-2 infection and provide important insights into signaling pathways that may be amenable to therapeutic intervention.