Incidental pulmonary nodule management in Canada: exploring current state through a narrative literature review and expert interviews.

Background and Objective: Incidental pulmonary nodules (IPNs) are common and increasingly detected with the overall rise of radiologic imaging. Effective IPN management is necessary to ensure lung cancer is not missed. This study aims to describe the current landscape of IPN management in Canada, understand barriers to optimal IPN management, and identify opportunities for improvement. Methods: We performed a narrative literature review by searching biomedical electronic databases for relevant articles published between January 1, 2010, and November 22, 2023. To validate and complement the identified literature, we conducted structured interviews with multidisciplinary experts involved in the pathway of patients with IPNs across Canada. Interviews between December 2021 and May 2022 were audiovisual recorded, transcribed, and thematically analyzed. Key Content and Findings: A total of 1,299 records were identified, of which 37 studies were included for analysis. Most studies were conducted in Canada and the United States and highlighted variability in radiology reporting of IPNs and patient management, and limited adherence to recommended follow-up imaging. Twenty experts were interviewed, including radiologists, respirologists, thoracic surgeons, primary care physicians, medical oncologists, and an epidemiologist. Three themes emerged from the interviews, supported by the literature, including: variability in radiology reporting of IPNs, suboptimal communication, and variability in guideline adherence and patient management. Conclusions: Despite general awareness of guidelines, there is inconsistency and lack of standardization in the management of patients with IPNs in Canada. Multidisciplinary expert consensus is recommended to help overcome the communication and operational barriers to a safe and cost-effective approach to this common clinical issue.

Impact of poor medication adherence on clinical outcomes and health resource utilization in patients with hypertension and/or dyslipidemia: systematic review.

INTRODUCTION: We aimed to summarize evidence on the effect of poor medication adherence on clinical outcomes and health resource utilization (HRU) among patients with hypertension and/or dyslipidemia. AREAS COVERED: A systematic review of studies reporting clinical outcomes and HRU for patients by status of adherence to antihypertensives and/or lipid-lowering medications was searched using Embase, MEDLINE, and MEDLINE In-Process and supplemented by manual searches of conference abstracts. In total, 45 studies were included, with most being retrospective observational studies (n = 36). Patients with poor adherence to antihypertensives and lipid-lowering medications compared with those with good adherence showed less reduction of blood pressure (BP) and low-density lipoprotein cholesterol (LDL-c) after 6-12 months follow-up (∆ systolic BP: 1.2 vs. -4.5 mmHg; ∆LDL-c: -14.0 to -18.9 vs. -34.1 to -42.0 mg/dL). Poor adherence was also significantly associated with a higher risk of cardiovascular events (HR: 1.1-1.9) and mortality (HR: 1.4-1.8) in patients with hypertension and dyslipidemia and increased HRU (i.e. outpatient visits, risk of cardiovascular-related and all-cause hospitalization, annual inpatient days, total health-care costs). EXPERT OPINION: Poor adherence is associated with poor clinical outcomes and increased HRU, highlighting the need to enhance medication adherence in patients with hypertension and/or dyslipidemia.

High blood pressure is a leading cause of death and disease burden followed by high lipid levels in blood. Due to the silent nature of the diseases, patients can fall short of optimal medicinal treatment adherence and persistence, leading to poor outcomes and disease complications. The effectiveness of medicinal interventions depends on the appropriate medication-taking behavior of patients as lower adherence can lead to poor treatment benefits. Research was conducted to look for published studies that assessed the effect of lower medication adherence on clinical outcomes and health resource use among patients with high blood pressure, high lipid levels in blood, or both. Researchers were able to find 45 already published studies, from which 32 evaluated the use of blood pressure lowering medications and 7 evaluated the use of lipid-lowering medications, while 6 included patients treated with both types of medications. Refill of pharmacy prescription records was the most common method of assessing treatment adherence. Researchers found that patients with lower adherence to these medications compared with those with good adherence showed less decrease in blood pressure levels and less improvement in blood lipid levels after 6­12 months of follow-up. Patients who had lower adherence also had higher rates of cardiovascular events and deaths and increased usage of health services including visits to outpatient clinics, getting admitted to hospitals, and a longer stay of hospitalizations, leading to a higher overall healthcare cost. These findings suggest lower adherence is associated with poor clinical outcomes and increased health-care resource usage, highlighting the need to improve medication adherence in patients with high blood pressure and high lipid levels in blood.

Growth exponents reflect evolutionary processes and treatment response in brain metastases.

Tumor growth is the result of the interplay of complex biological processes in huge numbers of individual cells living in changing environments. Effective simple mathematical laws have been shown to describe tumor growth in vitro, or simple animal models with bounded-growth dynamics accurately. However, results for the growth of human cancers in patients are scarce. Our study mined a large dataset of 1133 brain metastases (BMs) with longitudinal imaging follow-up to find growth laws for untreated BMs and recurrent treated BMs. Untreated BMs showed high growth exponents, most likely related to the underlying evolutionary dynamics, with experimental tumors in mice resembling accurately the disease. Recurrent BMs growth exponents were smaller, most probably due to a reduction in tumor heterogeneity after treatment, which may limit the tumor evolutionary capabilities. In silico simulations using a stochastic discrete mesoscopic model with basic evolutionary dynamics led to results in line with the observed data.

Protocol to generate murine organotypic brain cultures for drug screening and evaluation of anti-metastatic efficacy.

Organotypic brain cultures are short-term assays that phenotypically and functionally recapitulate brain metastatic cells in vivo. Here, we present a protocol to generate murine organotypic brain cultures for drug screening. We describe steps for sectioning of murine brains and plating of organotypic cultures. We then detail evaluation of the anti-metastatic effect of chemical compounds through bioluminescence imaging before and after drug treatment. Combined with downstream applications, this protocol allows comprehensive characterizations of both cancer cells and the tumor-associated microenvironment. For complete details on the use and execution of this protocol, please refer to Zhu et al. (2022).1.

A clinically compatible drug-screening platform based on organotypic cultures identifies vulnerabilities to prevent and treat brain metastasis.

We report a medium-throughput drug-screening platform (METPlatform) based on organotypic cultures that allows to evaluate inhibitors against metastases growing in situ. By applying this approach to the unmet clinical need of brain metastasis, we identified several vulnerabilities. Among them, a blood-brain barrier permeable HSP90 inhibitor showed high potency against mouse and human brain metastases at clinically relevant stages of the disease, including a novel model of local relapse after neurosurgery. Furthermore, in situ proteomic analysis applied to metastases treated with the chaperone inhibitor uncovered a novel molecular program in brain metastasis, which includes biomarkers of poor prognosis and actionable mechanisms of resistance. Our work validates METPlatform as a potent resource for metastasis research integrating drug-screening and unbiased omic approaches that is compatible with human samples. Thus, this clinically relevant strategy is aimed to personalize the management of metastatic disease in the brain and elsewhere.

Dianhydrogalactitol Overcomes Multiple Temozolomide Resistance Mechanisms in Glioblastoma.

Glioblastoma (GBM) is the most frequent and aggressive primary tumor type in the central nervous system in adults. Resistance to chemotherapy remains one of the major obstacles in GBM treatment. Identifying and overcoming the mechanisms of therapy resistance is instrumental to develop novel therapeutic approaches for patients with GBM. To determine the major drivers of temozolomide (TMZ) sensitivity, we performed shRNA screenings in GBM lines with different O6-methylguanine-DNA methyl-transferase (MGMT) status. We then evaluated dianhydrogalactitol (Val-083), a small alkylating molecule that induces interstrand DNA crosslinking, as a potential treatment to bypass TMZ-resistance mechanisms. We found that loss of mismatch repair (MMR) components and MGMT expression are mutually exclusive mechanisms driving TMZ resistance in vitro Treatment of established GBM cells and tumorsphere lines with Val-083 induces DNA damage and cell-cycle arrest in G2-M phase, independently of MGMT or MMR status, thus circumventing conventional resistance mechanisms to TMZ. Combination of TMZ and Val-083 shows a synergic cytotoxic effect in tumor cells in vitro, ex vivo, and in vivo We propose this combinatorial treatment as a potential approach for patients with GBM.

Universal scaling laws rule explosive growth in human cancers.

Most physical and other natural systems are complex entities composed of a large number of interacting individual elements. It is a surprising fact that they often obey the so-called scaling laws relating an observable quantity with a measure of the size of the system. Here we describe the discovery of universal superlinear metabolic scaling laws in human cancers. This dependence underpins increasing tumour aggressiveness, due to evolutionary dynamics, which leads to an explosive growth as the disease progresses. We validated this dynamic using longitudinal volumetric data of different histologies from large cohorts of cancer patients. To explain our observations we put forward increasingly-complex biologically-inspired mathematical models that captured the key processes governing tumor growth. Our models predicted that the emergence of superlinear allometric scaling laws is an inherently three-dimensional phenomenon. Moreover, the scaling laws thereby identified allowed us to define a set of metabolic metrics with prognostic value, thus providing added clinical utility to the base findings.

Transcriptomic Hallmarks of Tumor Plasticity and Stromal Interactions in Brain Metastasis.

The brain is a major site of relapse for several cancers, yet deciphering the mechanisms of brain metastasis remains a challenge because of the complexity of the brain tumor microenvironment (TME). To define the molecular landscape of brain metastasis from intact tissue in vivo, we employ an RNA-sequencing-based approach, which leverages the transcriptome of xenografts and distinguishes tumor cell and stromal gene expression with improved sensitivity and accuracy. Our data reveal shifts in epithelial and neuronal-like lineage programs in malignant cells as they adapt to the brain TME and the reciprocal neuroinflammatory response of the stroma. We identify several transcriptional hallmarks of metastasis that are specific to particular regions of the brain, induced across multiple tumor types, and confirmed in syngeneic models and patient biopsies. These data may serve as a resource for exploring mechanisms of TME co-adaptation within, as well as across, different subtypes of brain metastasis.

Impact of topical corticosteroid pretreatment on susceptibility of the injured murine cornea to Pseudomonas aeruginosa colonization and infection.

Research with animal models of Pseudomonas aeruginosa keratitis has shown that use of a topical corticosteroid alone against an established infection can significantly increase the number of colonizing bacteria or worsen clinical disease. Moreover, retrospective analysis has suggested that corticosteroid use in humans is associated with an increased risk of keratitis in eyes with pre-existing disease. Thus, while corticosteroids are often used to reduce ocular inflammation in the absence of infection, the risk of opportunistic infection remains a concern. However, the effect of corticosteroids on the intrinsic barrier function of uninfected corneas is unknown. Here, we tested if short-term topical corticosteroid treatment of an uninfected murine cornea would increase susceptibility to P. aeruginosa colonization or infection after epithelial injury. Topical prednisolone acetate (1%) was administered to one eye of C57BL/6 mice three times a day for 3 days; control eyes were treated with sterile PBS. Prior to inoculation with a cytotoxic P. aeruginosa corneal isolate strain 6206, corneas were subject to superficial-injury by tissue paper blotting, or scratch-injured followed by 12 h of healing. Previously we have shown that blotting renders mouse corneas susceptible to P. aeruginosa adhesion, but not infection, while 12 h healing reduces susceptibility to infection after scratching. Corneas were evaluated at 48 h for bacterial colonization and microbial keratitis (MK). To monitor impact on wound healing, corneal integrity was examined by fluorescein staining immediately after scarification and after 12 h healing. For both the tissue paper blotting and scratch-injury models, there was no significant difference in P. aeruginosa colonization at 48 h between corticosteroid-pretreated eyes and controls. With the blotting model, one case of MK was observed in a control (PBS-pretreated) cornea; none in corticosteroid-pretreated corneas. With the 12 h healing model, MK occurred in 6 of 17 corticosteroid-pretreated eyes versus 2 of 17 controls, a difference not statistically significant. Corticosteroid-pretreated eyes showed greater fluorescein staining 12 h after scarification injury, but this did not coincide with increased colonization or MK. Together, these data show that short-term topical corticosteroid therapy on an uninfected murine cornea does not necessarily enhance its susceptibility to P. aeruginosa colonization or infection after injury, even when it induces fluorescein staining.

Author Correction: STAT3 labels a subpopulation of reactive astrocytes required for brain metastasis.

In the version of this article originally published, the names of three authors were incorrect. The authors were listed as "Coral Fustero-Torres", "Elena Pineiro" and "Melchor Sánchez-Martínez". Their respective names are "Coral Fustero-Torre", "Elena Piñeiro-Yáñez" and "Melchor Sanchez-Martinez". The errors have been corrected in the print, HTML and PDF versions of this article.

STAT3 labels a subpopulation of reactive astrocytes required for brain metastasis.

The brain microenvironment imposes a particularly intense selective pressure on metastasis-initiating cells, but successful metastases bypass this control through mechanisms that are poorly understood. Reactive astrocytes are key components of this microenvironment that confine brain metastasis without infiltrating the lesion. Here, we describe that brain metastatic cells induce and maintain the co-option of a pro-metastatic program driven by signal transducer and activator of transcription 3 (STAT3) in a subpopulation of reactive astrocytes surrounding metastatic lesions. These reactive astrocytes benefit metastatic cells by their modulatory effect on the innate and acquired immune system. In patients, active STAT3 in reactive astrocytes correlates with reduced survival from diagnosis of intracranial metastases. Blocking STAT3 signaling in reactive astrocytes reduces experimental brain metastasis from different primary tumor sources, even at advanced stages of colonization. We also show that a safe and orally bioavailable treatment that inhibits STAT3 exhibits significant antitumor effects in patients with advanced systemic disease that included brain metastasis. Responses to this therapy were notable in the central nervous system, where several complete responses were achieved. Given that brain metastasis causes substantial morbidity and mortality, our results identify a novel treatment for increasing survival in patients with secondary brain tumors.

Human Tear Fluid Reduces Culturability of Contact Lens-Associated Pseudomonas aeruginosa Biofilms but Induces Expression of the Virulence-Associated Type III Secretion System.

PURPOSE: The type III secretion system (T3SS) is a significant virulence determinant for Pseudomonas aeruginosa. Using a rodent model, we found that contact lens (CL)-related corneal infections were associated with lens surface biofilms. Here, we studied the impact of human tear fluid on CL-associated biofilm growth and T3SS expression. METHODS: P. aeruginosa biofilms were formed on contact lenses for up to 7 days with or without human tear fluid, then exposed to tear fluid for 5 or 24 h. Biofilms were imaged using confocal microscopy. Bacterial culturability was quantified by viable counts, and T3SS gene expression measured by RT-qPCR. Controls included trypticase soy broth, PBS and planktonic bacteria. RESULTS: With or without tear fluid, biofilms grew to ∼108 CFU viable bacteria by 24 h. Exposing biofilms to tear fluid after they had formed without it on lenses reduced bacterial culturability ∼180-fold (P<.001). CL growth increased T3SS gene expression versus planktonic bacteria [5.46 ± 0.24-fold for T3SS transcriptional activitor exsA (P=.02), and 3.76 ± 0.36-fold for T3SS effector toxin exoS (P=.01)]. Tear fluid further enhanced exsA and exoS expression in CL-grown biofilms, but not planktonic bacteria, by 2.09 ± 0.38-fold (P=.04) and 1.89 ± 0.26-fold (P<.001), respectively. CONCLUSIONS: Considering the pivitol role of the T3SS in P. aeruginosa infections, its induction in CL-grown P. aeruginosa biofilms by tear fluid might contribute to the pathogenesis of CL-related P. aeruginosa keratitis.

Pseudomonas aeruginosa Survival at Posterior Contact Lens Surfaces after Daily Wear.

PURPOSE: Pseudomonas aeruginosa keratitis is a sight-threatening complication of contact lens wear, yet mechanisms by which lenses predispose to infection remain unclear. Here, we tested the hypothesis that tear fluid at the posterior contact lens surface can lose antimicrobial activity over time during lens wear. METHODS: Daily disposable lenses were worn for 1, 2, 4, 6, or 8 hours immediately after removal from their packaging or after presoaking in sterile saline for 2 days to remove packaging solution. Unworn lenses were also tested, some coated in tears "aged" in vitro for 1 or 8 hours. Lenses were placed anterior surface down into tryptic soy agar cradles containing gentamicin (100 µg/mL) to kill bacteria already on the lens and posterior surfaces inoculated with gentamicin-resistant P. aeruginosa for 3 hours. Surviving bacteria were enumerated by viable counts of lens homogenates. RESULTS: Posterior surfaces of lenses worn by patients for 8 hours supported more P. aeruginosa growth than lenses worn for only 1 hour, if lenses were presoaked before wear (∼ 2.4-fold, p = 0.01). This increase was offset if lenses were not presoaked to remove packaging solution (p = 0.04 at 2 and 4 hours). Irrespective of presoaking, lenses worn for 8 hours showed more growth on their posterior surface than unworn lenses coated with tear fluid that was aged for 8 hours in vitro (∼ 8.6-fold, presoaked, p = 0.003; ∼ 5.4-fold from packaging solution, p = 0.004). Indeed, in vitro incubation did not impact tear antimicrobial activity. CONCLUSIONS: This study shows that postlens tear fluid can lose antimicrobial activity over time during contact lens wear, supporting the idea that efficient tear exchange under a lens is critical for homeostasis. Additional studies are needed to determine applicability to other lens types, wearing modalities, and relevance to contact lens-related infections.