High Plasma Osteopontin Levels Are Associated with Serious Post-Acute-COVID-19-Related Dyspnea

COVID-19 survivors commonly report persistent symptoms. In this observational study, we investigated the link between osteopontin (OPN) and post-acute COVID-19 symptoms and lung functional/imaging abnormalities. We recorded symptoms and lung imaging/functional data from previously hospitalized COVID-19 patients, who were followed for 4-84 weeks (122 patients/181 visits) post-symptom onset at our outpatient clinic. Circulating OPN was determined using ELISA. Plasma OPN levels were higher in symptomatic patients (compared with the asymptomatic ones); those with dyspnea (compared with those without dyspnea);those with a combination of serious symptoms, i.e., the presence of at least one of the following: dyspnea, fatigue and muscular weakness (compared with those with none of these symptoms); and those with dyspnea and m-MRC > 1 (compared with those with m-MRC = 0-1). Plasma OPN levels were inversely correlated with EQ-VAS (visual analog scale of the EQ-5D-5L health-related quality-of-life questionnaire) values. High-resolution CT or diffusion lung capacity (DLCO) findings were not related to circulating OPN. In the multiple logistic regression, the presence of symptoms, dyspnea, or the combination of serious symptoms were linked to female gender, increased BMI and pre-existing dyspnea (before the acute disease), while increased plasma OPN levels, female gender and pre-existing dyspnea with m-MRC > 1 were independently associated with severe post-COVID-19 dyspnea (m-MRC > 1). Using a correlation matrix to investigate multiple correlations between EQ-VAS, OPN and epidemiological data, we observed an inverse correlation between the OPN and EQ-VAS values. Increased circulating OPN was linked to the persistence of severe exertional dyspnea and impaired quality of life in previously hospitalized COVID-19 patients.

MTH1 Inhibition Alleviates Immune Suppression and Enhances the Efficacy of Anti-PD-L1 Immunotherapy in Experimental Mesothelioma

BACKGROUND

MTH1 protects tumor cells and their supporting endothelium from lethal DNA damage triggered by oxidative stress in the tumor microenvironment, thus promoting tumor growth. The impact of MTH1 on the tumor-related immune compartment remains unknown. We hypothesized that MTH1 regulates immune fitness and therefore enhances the activity of currently used immunotherapeutic regimens.

METHODS

Our hypotheses were validated in two syngeneic murine mesothelioma models using the clinically relevant MTH1 inhibitor, karonudib. We also examined the effect of combined MTH1 and PD-L1 blockade in mesothelioma progression, focusing on the main immune players.

RESULTS

Karonudib administration enhances M1 macrophage polarization, stimulates CD8 expansion and promotes the activation of DC and T cells. Combined administration of PD-L1 and MTH1 inhibitors impairs mesothelioma tumor growth and mesothelioma-associated pleural effusion accumulation more effectively compared to each monotherapy.

CONCLUSIONS

Combined MTH1 and PD-L1 inhibition holds promise for the successful clinical management of mesothelioma.

CSF1/CSF1R signaling mediates malignant pleural effusion formation

Malignant pleural effusion (MPE) is an incurable common manifestation of many malignancies. Its formation is orchestrated by complex interactions among tumor cells, inflammatory cells, and the vasculature. Tumor-associated macrophages present the dominant inflammatory population of MPE, and M2 macrophage numbers account for dismal prognosis. M2 polarization is known to be triggered by CSF1/CSF1 receptor (CSF1R) signaling. We hypothesized that CSF1R⁺ M2 macrophages favor MPE formation and could be therapeutically targeted to limit MPE. We generated mice with CSF1R-deficient macrophages and induced lung and colon adenocarcinoma–associated MPE. We also examined the therapeutic potential of a clinically relevant CSF1R inhibitor (BLZ945) in lung and colon adenocarcinoma–induced experimental MPE. We showed that CSF1R⁺ macrophages promoted pleural fluid accumulation by enhancing vascular permeability, destabilizing tumor vessels, and favoring immune suppression. We also showed that CSF1R inhibition limited MPE in vivo by reducing vascular permeability and neoangiogenesis and impeding tumor progression. This was because apart from macrophages, CSF1R signals in cancer-associated fibroblasts leading to macrophage inflammatory protein 2 secretion triggered the manifestation of suppressive and angiogenic properties in macrophages upon CXCR2 paracrine activation. Pharmacological targeting of the CSF1/CSF1R axis can therefore be a vital strategy for limiting MPE.

MTH1 favors mesothelioma progression and mediates paracrine rescue of bystander endothelium from oxidative damage

Oxidative stress and inadequate redox homeostasis is crucial for tumor initiation and progression. MTH1 (NUDT1) enzyme prevents incorporation of oxidized dNTPs by sanitizing the deoxynucleoside triphosphate (dNTP) pool and is therefore vital for the survival of tumor cells. MTH1 inhibition has been found to inhibit the growth of several experimental tumors, but its role in mesothelioma progression remained elusive. Moreover, although MTH1 is nonessential to normal cells, its role in survival of host cells in tumor milieu, especially tumor endothelium, is unclear. We validated a clinically relevant MTH1 inhibitor (Karonudib) in mesothelioma treatment using human xenografts and syngeneic murine models. We show that MTH1 inhibition impedes mesothelioma progression and that inherent tumoral MTH1 levels are associated with a tumor's response. We also identified tumor endothelial cells as selective targets of Karonudib and propose a model of intercellular signaling among tumor cells and bystander tumor endothelium. We finally determined the major biological processes associated with elevated MTH1 gene expression in human mesotheliomas.

Interleukin-27 improves the ability of adenosine deaminase to rule out tuberculous pleural effusion regardless of pleural tuberculosis prevalence

BACKGROUND

Interleukin-27 (IL-27) has been proposed to be useful for diagnosing tuberculous pleural effusion (TPE). Adenosine deaminase (ADA) has been long used for the same purpose. The aim of this study was to compare the performance of IL-27, ADA, and their product (IL-27 • ADA) in the diagnosis of TPE.

METHODS

Pleural fluid samples from patients with exudative pleural effusions were assessed for IL-27 and ADA levels. Receiver operating characteristic (ROC) curves were constructed to compare the overall diagnostic accuracy of IL-27, ADA, and IL-27 • ADA. Curves of false-positive (FPR) and false-negative (FNR) rates as a function of TPE prevalence were also constructed, and mean rates of false results in low (1-10%), intermediate (11-40%), and high (41-70%) prevalences were estimated to evaluate the ability of the three markers in ruling in or ruling out TPE.

RESULTS

We studied 121 exudates. IL-27 and ADA were higher in TPEs compared with non-TPEs and they presented similar accuracies for the diagnosis of TPE. The product of IL-27 and ADA (IL-27 • ADA) was more accurate than ADA for the same purpose. IL-27 and IL-27 • ADA presented the lowest overall FPR and FNR, respectively. The FPR of IL-27, ADA and IL-27 • ADA was > 9%, even in high prevalence settings. Although their FNR was < 2% in low prevalence settings, only IL-27 • ADA exhibited sufficiently low FNR (< 1%) in intermediate and high prevalences.

CONCLUSIONS

ADA, IL-27, and IL-27 • ADA cannot reliably 'rule in' TPE in any prevalence setting. TPE can be 'ruled out' by each of the biomarkers in low prevalence settings. In intermediate and high prevalence settings, IL-27 • ADA is a reliable 'rule out' test in the diagnostic approach to TPEs.