Daily Respiratory Research Analysis
Three impactful respiratory-related studies span clinical and translational science: a double-blind RCT shows inhaled nitric oxide does not reduce AKI after prolonged cardiopulmonary bypass with endothelial dysfunction; a geometry-matched DNA nanostructure delivers multivalent ligands that broadly inhibit influenza across mouse and porcine models; and a T cell–only SARS-CoV-2 vaccine strategy gains durable protection when boosted intranasally, highlighting the value of mucosal resident memory T
Summary
Three impactful respiratory-related studies span clinical and translational science: a double-blind RCT shows inhaled nitric oxide does not reduce AKI after prolonged cardiopulmonary bypass with endothelial dysfunction; a geometry-matched DNA nanostructure delivers multivalent ligands that broadly inhibit influenza across mouse and porcine models; and a T cell–only SARS-CoV-2 vaccine strategy gains durable protection when boosted intranasally, highlighting the value of mucosal resident memory T cells.
Research Themes
- Negative randomized evidence guiding perioperative respiratory therapies (inhaled NO and AKI prevention)
- Geometry-matched multivalency via DNA nanostructures for broad-spectrum respiratory antivirals
- Mucosal T cell–focused vaccination to counter variant escape in respiratory viruses
Selected Articles
1. Nitric Oxide to Reduce Acute Kidney Injury in Patients with Pre-existing Endothelial Dysfunction Requiring Prolonged Cardiopulmonary Bypass: A Randomized Clinical Trial.
In a double-blind randomized trial of 250 adults undergoing prolonged CPB with pre-existing endothelial dysfunction, perioperative 80 ppm inhaled NO for 24 hours did not reduce AKI (44.0% vs 43.2%; adjusted OR 1.00) or renal replacement therapy up to 1 year. The results do not support routine NO use for AKI prevention in this population.
Impact: A high-quality negative RCT resolves uncertainty from prior subgroup signals and prevents unnecessary perioperative NO use for AKI prevention. It guides resource allocation and protocol refinement in cardiac anesthesia and perfusion practice.
Clinical Implications: Do not routinely administer inhaled NO to reduce AKI in prolonged CPB patients with endothelial dysfunction; focus on alternative nephroprotective strategies and risk stratification. Consider limiting NO to indications with proven benefit.
Key Findings
- AKI incidence was similar with NO vs control (44.0% vs 43.2%; adjusted OR 1.00, 95% CI 0.59–1.69).
- No differences in AKI severity (KDIGO stages 1–3) or renal replacement therapy during hospitalization and at 6 weeks, 90 days, and 1 year.
- Double-blind, placebo-controlled design with NO delivered via oxygenator and postoperatively via ventilator/facemask for a total of 24 hours.
Methodological Strengths
- Double-blind, randomized, placebo-controlled trial with prespecified KDIGO-defined AKI endpoint.
- Extended outcome assessment including renal replacement therapy up to 1 year.
Limitations
- Single-center study may limit generalizability across surgical programs and perfusion practices.
- Potential underpowering for modest effects in subgroups; biochemical characterization of endothelial dysfunction not detailed in the abstract.
Future Directions: Multicenter trials with biomarker-defined subgroups and alternative dosing/duration strategies may identify populations benefiting from NO. Explore complementary hemolysis-mitigation or endothelial-protective strategies during CPB.
BACKGROUND: Prolonged cardiopulmonary bypass (CPB) causes hemolysis, reducing nitric oxide (NO) availability and increasing the risk of acute kidney injury (AKI) after cardiac surgery. While prior studies suggest inhaled NO may reduce AKI in certain populations, its effect in patients with pre-existing endothelial dysfunction, a condition marked by impaired NO production is unknown. This trial investigates whether perioperative NO administration reduces AKI in patients with pre-existing endothelial dysfunction undergoing prolonged CPB. METHODS: We conducted a double-blind, single-center, placebo-controlled, randomized clinical trial involved 250 adult cardiac surgery patients with pre-existing endothelial dysfunction undergoing cardiopulmonary bypass lasting more than 90 minutes. Participants were randomized to either receive NO at 80 ppm via the oxygenator during cardiopulmonary bypass, continuing post-operatively via ventilator and facemask, or a placebo of nitrogen-oxygen gas mixture for 24 hours. The primary outcome was the incidence of post-operative AKI, defined by KDIGO criteria. Secondary outcomes included AKI severity, and the need for renal replacement therapy (RRT) during hospitalization and at 6 weeks, 90 days, and 1 year. RESULTS: Of the 250 patients [median age: 66 (59, 73) years; 56 (22.4%) females], 125 were assigned to each group. AKI occurred in 55 (44.0%) patients in the NO group and 54 (43.2%) patients in the control group [OR adj : 1.00 (95%CI: 0.59-1.69)]. Secondary outcomes, including stage 1, 2, or 3 AKI and RRT at all time points, were also similar between groups. CONCLUSIONS: In cardiac surgery patients with pre-existing endothelial dysfunction undergoing prolonged cardiopulmonary bypass, peri-operative administration of 80 ppm NO for 24 hours did not significantly reduce post-operative AKI. These findings do not support the routine use of NO in this patient population. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02836899.
2. DNA Nanostructure-Templated Multivalency Enables Broad-Spectrum Virus Inhibition.
A honeycomb DNA nanostructure presenting trimeric HA-targeting ligands achieved geometry-matched multivalency that dramatically enhanced influenza neutralization. The HC-Nanobody construct exceeded 99% entry inhibition and improved viability by 35–45% in murine H1N1/H3N2, and retained >97% inhibition with 30–55% viability gains in a porcine model, indicating cross-species translational promise.
Impact: Introduces a modular, geometry-guided antiviral platform with robust efficacy across species, providing a blueprint for rapidly evolving respiratory pathogens where antigenic drift undermines monomeric inhibitors.
Clinical Implications: Supports development of reprogrammable intranasal or inhaled antivirals leveraging multivalency to counter antigenic escape in influenza and potentially other respiratory viruses. Preclinical safety, delivery, durability, and immunogenicity require evaluation.
Key Findings
- Honeycomb DNA nanostructures (HC-DDN) displaying trimeric HA ligands matched native HA geometry and enhanced neutralization.
- HC-Nanobody achieved >99% inhibition of viral entry and 35–45% improved cell viability at nanomolar concentrations in murine H1N1/H3N2 models.
- In a porcine influenza model, HC-Nanobody maintained >97% inhibition and 30–55% higher viability versus free nanobodies, indicating cross-species efficacy.
Methodological Strengths
- Rational, geometry-matched multivalency design rigorously tested across in vitro, murine, and porcine systems.
- Direct comparison to monomeric counterparts demonstrates clear added value of multivalency.
Limitations
- In vivo testing focused on influenza A; breadth against other respiratory viruses remains to be demonstrated.
- Clinical translation challenges (formulation, delivery, stability, immunogenicity) not yet addressed.
Future Directions: Optimize intranasal delivery and pharmacokinetics, expand to other respiratory pathogens (e.g., RSV, SARS-CoV-2), and evaluate safety/efficacy in GLP toxicology and early-phase human studies.
The rapid evolution and antigenic diversity of influenza A viruses (IAVs) continue to challenge antiviral strategies, highlighting the need for broadly effective and modular therapeutic platforms. While single-domain nanobodies and DNA aptamer-based inhibitors have emerged as promising candidates, their efficacy is limited by monomeric binding to the hemagglutinin (HA) proteins populating the viral envelope. A programmable antiviral platform based on a honeycomb-shaped designer DNA nanostructure (HC-DDN) engineered to multivalently display HA-targeting ligands with nanometer precision is presented. Two constructs are synthesized, HC-Nanobody and HC-Aptamer, organized in trimeric clusters to match the native HA trimer geometry. Using murine-adapted H1N1 and H3N2 models, it is shown that both constructs outperform their free counterparts in viral neutralization and cytoprotection. HC-Nanobody construct achieves >99% inhibition of viral entry and improves cell viability by 35-45% at nanomolar concentrations. To assess translational relevance, the HC-Nanobody construct in a porcine IAV infection model is further evaluated, where it maintains high antiviral efficacy (>97% inhibition) and confers a 30-55% increase in cell viability relative to free nanobodies, confirming robust cross-species performance. Overall, this work demonstrates the power of geometry-matched multivalency to enhance viral neutralization and provides a rational blueprint for designing broad-spectrum antivirals against rapidly evolving respiratory pathogens.
3. Conserved CD8 T cell vaccines without B cell epitopes drive robust protection against SARS-CoV-2 that is enhanced by intranasal boost.
In mice, subcutaneous vaccines composed of conserved CD8 T cell epitopes reduced lung viral load and protected against low-dose SARS-CoV-2, while an intranasal boost (with or without adjuvant) enhanced lung resident memory T cells and conferred durable protection even against high-dose challenge. The work supports mucosal T cell–focused vaccination to broaden immunity against evolving respiratory viruses.
Impact: Highlights a T cell–only vaccine strategy augmented by mucosal boosting, addressing antibody escape and emphasizing conserved epitopes for durable, variant-resilient protection.
Clinical Implications: Supports the rationale for intranasal T cell–boosting strategies to complement or update current vaccines, potentially improving breadth and durability against variants and other respiratory viruses.
Key Findings
- Identified Omicron BA.1-specific and Wuhan-conserved CD8 T cell epitopes within spike and built carrier-fusion vaccines.
- Subcutaneous immunization with two CD8 epitope peptides lowered lung viral loads and protected against low-dose challenge but not high-dose.
- Intranasal boosting (± adjuvant) enhanced lung resident memory T cells and conferred potent, durable protection against high-dose infection.
Methodological Strengths
- Combines epitope discovery with functional in vivo vaccination and challenge models.
- Direct comparison of systemic versus mucosal boosting clarifies the role of resident memory T cells.
Limitations
- Mouse model findings may not fully translate to humans; safety of T cell–only vaccination requires clinical evaluation.
- Focus on spike epitopes; breadth across proteins and impact on transmission were not assessed.
Future Directions: Advance to human studies of intranasal T cell boosters, broaden epitope sets across conserved proteins, and evaluate efficacy against transmission and across variant landscapes.
The emergence of SARS-CoV-2 variants has challenged the current spike protein-focused COVID-19 vaccine strategy due to neutralizing antibody escape and waning antibody-mediated immunity. In contrast, T cell-mediated immunity targeting conserved epitopes may offer broad and long-lasting protection. However, whether T cells alone can provide sufficient protection remains unclear. Here, we identified both Omicron BA.1-specific and ancestral (Wuhan)-conserved CD8 T cell epitopes in the SARS-CoV-2 spike protein and evaluated them as carrier-protein fusion vaccines in mouse models. Subcutaneous immunizations with two CD8 epitope peptides substantially lowered lung viral load and conferred protection against low-dose viral challenge, but not against high-dose challenge. Notably, intranasal boosting-with or without adjuvant-enhanced lung resident memory T cell responses and conferred potent, durable protection against high-dose infection. These findings emphasize the importance of mucosal vaccination to boost protective T cell immunity against SARS-CoV-2 and support the potential of T cell-based vaccines targeting conserved epitopes for broad immunity against SARS-CoV-2 and other respiratory viral threats.