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► Assays to quantify cancer biomarkers with high sensitivity and low sample volumes. ► Imaging of cancer cells, tissues, and small animals with multiplexed capabilities. ► Multimodal SERS probes and their potential for clinical translation. Technologies that use surface-enhanced Raman scattering (SERS) have experienced significant growth in biomedical research during the past 4 years. In this review we summarize the progress in SERS for cancer diagnostics, including multiplexed detection and identification of new biomarkers, single-nucleotide polymorphisms, and circulating tumor cells. SERS is also used as a non-invasive tool for cancer imaging with immunoSERS microscopy, histological analysis of biopsies, and in vivo detection of tumors. We discuss the future of SERS probes compatible with multiple imaging modalities and their potential for clinical translation (e.g., endoscope-based and intraoperative imaging as tools for surgical guidance). Moreover, we highlight the potential of SERS agents for targeted drug delivery and photothermal therapy.

The COVID-19 pandemic has highlighted the importance of efficient drug discovery in respiratory disease. The traditional set up of clinical trials is expensive and allows for significant attrition of new drugs, many of which undergo extensive safety testing before being abandoned for lack of efficacy. Phase 0 trials, named as they sit between pre-clinical research and phase I, allow for the testing of sub-clinical microdoses in humans to gather early pharmacokinetic (PK), pharmacodynamic (PD) and mechanistic data, before deciding on which drugs to advance further. This early data can improve the efficiency and cost effectiveness of drug development and reduce the extent of animal testing. Phase 0 trials traditionally have utilised sub-therapeutic microdoses of compounds administered intravenously with readouts focusing on PK - measured using highly sensitive methods such as accelerator mass spectrometry (AMS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) of peripheral blood, as well as whole-body positron emission tomography (PET). Mathematical models allow for extrapolation of this PK data to support the further testing of larger, systemically effective doses. However, this extrapolation method is limited at providing robust PD or target engagement/ mode of action data. Using an Intra-Target Microdosing (ITM) approach, a small compartment of the body (about 1% or less) is exposed to potentially clinically active local concentrations. This allows for the collection of PD data, evidence of target cell engagement, as well as the opportunity to extrapolate systemic PK and PD data. This approach has the potential within the pulmonary system for the study and rapid and cost-effective development of new and repurposed drugs.

There is increasing evidence that lung-resident memory T and B cells play a critical role in protecting against respiratory reinfection. With a unique transcriptional and phenotypic profile, resident memory lymphocytes are maintained in a quiescent state, constantly surveying the lung for microbial intruders. Upon reactivation with cognate antigen, these cells provide rapid effector function to enhance immunity and prevent infection. Immunization strategies designed to induce their formation, alongside novel techniques enabling their detection, have the potential to accelerate and transform vaccine development. Despite most data originating from murine studies, this review will discuss recent insights into the generation, maintenance and characterisation of pulmonary resident memory lymphocytes in the context of respiratory infection and vaccination using recent findings from human and non-human primate studies.

Minimizing unintended granulocyte activation while measuring functional responsiveness is essential, as the use of external probes, antibodies, or fluorescent dyes can potentially alter cellular responsiveness. To address this, we employed an antibody-free flow cytometry approach that measures forward scatter (FSC) to detect variations in cell-size, morphology, and shape; some key indicators of neutrophil and eosinophil activation. Human peripheral blood neutrophils, containing contaminating eosinophils, were isolated using discontinuous Percoll gradients and pre-treated with receptor antagonists [e.g., cyclosporin-H (an FPR1 antagonist) and CP105696 (a BLT1 receptor antagonist)] prior to stimulation with agonists such as fMLF (an FPR1 agonist) and LTB 4 (a BLT1 agonist). Furthermore, fMLF stimulation resulted in a loss of CD62L and an increase in CD11b expression along with an increase in intracellular ROS production compared to control, as analysed using flow cytometry. Imaging flow cytometry, together with FSC analysis, enabled assessment of cell polarization and associated morphological changes. Importantly, autofluorescence-based gating allowed for the identification of contaminating eosinophils within the mixed granulocyte population, allowing parallel assessment of shape-change in both neutrophils and eosinophils in response to the same ligands. Stimulation of neutrophils with fMLF resulted in distinct FSC shifts compared to unstimulated controls across all flow cytometers tested, which were inhibited by cyclosporin-H, but not CP105696. Morphological analysis confirmed these changes corresponded with increased cell area and perimeter and decreased circularity, hallmarks of cell polarisation. Additionally, selective activation of eosinophils (but not neutrophils) by eotaxin, and dual activation of both cell types by the arachidonic acid metabolite 5-oxo-ETE, were confirmed through specific gating strategies. Taken together, these findings support the use of FSC-based flow cytometry as a rapid, scalable and effective method for evaluating granulocyte polarisation and screening candidate therapeutics targeting immune cell activation in disease contexts.

Far-ultraviolet C (Far-UVC) radiation, with a wavelength range from 200 to 235 nm, is germicidal and holds potential for clinical applications. However, its use against deep-seated and internal infections, such as those affecting the lungs, remains less well established. The safety profile of Far-UVC irradiation requires further investigation across different human tissues. In this study, we utilised a krypton-chloride excimer lamp and a pulsed laser system to examine the effects of Far-UVC irradiation on human lung cells in vitro and primary human tracheal tissue. Primary human tracheal tissue and cells exposed to continuous wave (222 nm) and pulsed 206 nm and 222 nm light at doses of 5, 25, and 50 mJ/cm 2 exhibited DNA damage, including phosphorylation of γH2AX (Ser139). The continuous wave and pulsed 222 nm irradiation caused the formation of pyrimidine-pyrimidone (6-4) photoproducts. Irradiated human lung cells demonstrated reduced viability in vitro, and increased lactate dehydrogenase release into the culture medium 48 h post-irradiation. Our findings reveal that even low doses of Far-UVC (206 nm, 222 nm) light can penetrate monolayers of human lung epithelial cells, causing direct DNA damage in the form of (6 -4) photoproducts and DNA double-strand breaks, ultimately leading to cell death.

Rapid in situ detection of pathogens coupled with high resolution imaging in the distal human lung has the potential to provide new insights and diagnostic utility in patients in whom pneumonia is suspected. We have previously described an antimicrobial peptide (AMP) Ubiquicidin (fragment UBI 29–41 ) labelled with an environmentally sensitive fluorophore that optically detected bacteria in vitro but not ex vivo . Here, we describe further chemical development of this compound and demonstrate that altering the secondary structure of the AMP to generate a tri-branched dendrimeric scaffold provides enhanced signal in vitro and ex vivo and consequently allows the rapid detection of pathogens in situ in an explanted human lung. This compound (NBD-UBI dend ) demonstrates bacterial labelling specificity for a broad panel of pathogenic bacteria and Aspergillus fumigatus . NBD-UBI dend demonstrated high signal-to-noise fluorescence amplification upon target engagement, did not label host mammalian cells and was non-toxic and chemically robust within the inflamed biological environment. Intrapulmonary delivery of NBD-UBI dend , coupled with optical endomicroscopy demonstrated real-time, in situ detection of bacteria in explanted whole human Cystic Fibrosis lungs.

Abstract Rationale Acute lung injury (ALI) is an important cause of morbidity and mortality, with no currently effective pharmacological therapies. Neutrophils have been specifically implicated in the pathogenesis of ALI, and there has been significant research into the mechanisms of early neutrophil recruitment, but those controlling the later phases of neutrophil emigration that characterize disease are poorly understood. Objectives To determine the influence of peripheral blood monocytes (PBMs) in established ALI. Methods In a murine model of LPS-induced ALI, three separate models of conditional monocyte ablation were used: systemic liposomal clodronate (sLC), inducible depletion using CD11b diphtheria toxin receptor (CD11b DTR) transgenic mice, and antibody-dependent ablation of CCR2hi monocytes. Measurements and Main Results PBMs play a critical role in regulating neutrophil emigration in established murine LPS-induced lung injury. Gr1hi and Gr1lo PBM subpopulations contribute to this process. PBM depletion is associated with a significant reduction in measures of lung injury. The specificity of PBM depletion was demonstrated by replenishment studies in which the effects were reversed by systemic PBM infusion but not by systemic or local pulmonary infusion of mature macrophages or lymphocytes. Conclusions These results suggest that PBMs, or the mechanisms by which they influence pulmonary neutrophil emigration, could represent therapeutic targets in established ALI.

Background In this phase 2 randomised placebo-controlled clinical trial in patients with COVID-19, we hypothesised that blocking mineralocorticoid receptors using a combination of dexamethasone to suppress cortisol secretion and spironolactone is safe and may reduce illness severity. Methods Hospitalised patients with confirmed COVID-19 were randomly allocated to low dose oral spironolactone (50 mg day 1, then 25 mg once daily for 21 days) or standard of care in a 2:1 ratio. Both groups received dexamethasone 6 mg daily for 10 days. Group allocation was blinded to the patient and research team. Primary outcomes were time to recovery, defined as the number of days until patients achieved WHO Ordinal Scale (OS) category ≤ 3, and the effect of spironolactone on aldosterone, D-dimer, angiotensin II and Von Willebrand Factor (VWF). Results One hundred twenty patients with PCR confirmed COVID were recruited in Delhi from 01 February to 30 April 2021. 74 were randomly assigned to spironolactone and dexamethasone (SpiroDex), and 46 to dexamethasone alone (Dex). There was no significant difference in the time to recovery between SpiroDex and Dex groups (SpiroDex median 4.5 days, Dex median 5.5 days, p  = 0.055). SpiroDex patients had significantly lower D-dimer levels on days 4 and 7 (day 7 mean D-dimer: SpiroDex 1.15 µg/mL, Dex 3.15 µg/mL, p  = 0.0004) and aldosterone at day 7 (SpiroDex 6.8 ng/dL, Dex 14.52 ng/dL, p  = 0.0075). There was no difference in VWF or angiotensin II levels between groups. For secondary outcomes, SpiroDex patients had a significantly greater number of oxygen free days and reached oxygen freedom sooner than the Dex group. Cough scores were no different during the acute illness, however the SpiroDex group had lower scores at day 28. There was no difference in corticosteroid levels between groups. There was no increase in adverse events in patients receiving SpiroDex. Conclusion Low dose oral spironolactone in addition to dexamethasone was safe and reduced D-dimer and aldosterone. Time to recovery was not significantly reduced. Phase 3 randomised controlled trials with spironolactone and dexamethasone should be considered. Trial registration The trial was registered on the Clinical Trials Registry of India TRI: CTRI/2021/03/031721, reference: REF/2021/03/041472. Registered on 04/03/2021.

Neutrophil activation is an integral process to acute inflammation and is associated with adverse clinical sequelae. Identification of neutrophil activation in real time in the lungs of patients may permit biological stratification of patients in otherwise heterogenous cohorts typically defined by clinical criteria. No methods for identifying neutrophil activation in real time in the lungs of patients currently exist. We developed a bespoke molecular imaging probe targeting three characteristic signatures of neutrophil activation: pinocytosis, phagosomal alkalinisation, and human neutrophil elastase (HNE) activity. The probe functioned as designed in vitro and ex vivo . We evaluated optical endomicroscopy imaging of neutrophil activity using the probe in real-time at the bedside of healthy volunteers, patients with bronchiectasis, and critically unwell mechanically ventilated patients. We detected a range of imaging responses in vivo reflecting heterogeneity of condition and severity. We corroborated optical signal was due to probe function and neutrophil activation.

Pulmonary-resident memory T cells (T ) and B cells (B ) orchestrate protective immunity to reinfection with respiratory pathogens. Developing methods for the detection of these populations would benefit both research and clinical settings. To address this need, we developed a novel immunolabelling approach combined with clinic-ready fibre-based optical endomicroscopy (OEM) to detect canonical markers of lymphocyte tissue residency in human lungs undergoing lung ventilation (EVLV). Initially, cells from human lung digests (confirmed to contain T /B populations using flow cytometry) were stained with CD69 and CD103/CD20 fluorescent antibodies and imaged using KronoScan, demonstrating it's ability to detect antibody labelled cells. We next instilled these pre-labelled cells into human lungs undergoing EVLV and confirmed they could still be visualised using both fluorescence intensity and lifetime imaging against background lung architecture. Finally, we instilled fluorescent CD69 and CD103/CD20 antibodies directly into the lung and were able to detect T /B following labelling within seconds of direct delivery of microdoses of fluorescently labelled antibodies. , no wash, immunolabelling with OEM imaging is a novel methodology with the potential to expand the experimental utility of EVLV and pre-clinical models.