Since the beginning of the COVID-19 pandemic, the wastewater-based epidemiology (WBE) of SARS-CoV-2 has been used as a complementary indicator to follow up on the trends in the COVID-19 spread in Belgium and in many other countries. To further develop the use of WBE, a multiplex digital polymerase chain reaction (dPCR) assay was optimized, validated and applied for the measurement of emerging SARS-CoV-2 variants of concern (VOC) in influent wastewater (IWW) samples. Key mutations were targeted in the different VOC strains, including SΔ69/70 deletion, N501Y, SΔ241 and SΔ157. The presented bioanalytical method was able to distinguish between SARS-CoV-2 RNA originating from the wild-type and B.1.1.7, B.1.351 and B.1.617.2 variants. The dPCR assay proved to be sensitive enough to detect low concentrations of SARS-CoV-2 RNA in IWW since the limit of detection of the different targets ranged between 0.3 and 2.9 copies/µL. This developed WBE approach was applied to IWW samples originating from different Belgian locations and was able to monitor spatio-temporal changes in the presence of targeted VOC strains in the investigated communities. The present dPCR assay developments were realized to bring added-value to the current national WBE of COVID-19 by also having the spatio-temporal proportions of the VoC in presence in the wastewaters.

The chemotherapeutic agent doxorubicin (DOX) leads to the loss of skeletal muscle and adipose tissue mass, contributing to cancer cachexia. Experimental research on the molecular mechanisms of long-term DOX treatment is modest, and its effect on both skeletal muscle and adipose tissue has not been studied in an integrative manner. Dexrazoxane (DEXRA) is used to prevent DOX-induced cancer-therapy-related cardiovascular dysfunction (CTRCD), but its impact on skeletal muscle and adipose tissue remains elusive. Therefore, this study aimed to investigate the long-term effects of DOX on adipose tissue and skeletal muscle metabolism, and evaluate whether DEXRA can mitigate these effects. To this end, 10-week-old male C57BL6/J mice (n = 32) were divided into four groups: (1) DOX, (2) DOX-DEXRA combined, (3) DEXRA and (4) control. DOX (4 mg/kg weekly) and DEXRA (40 mg/kg weekly) were administered intraperitoneally over 6 weeks. Indirect calorimetry was used to assess metabolic parameters, followed by a molecular analysis and histological evaluation of skeletal muscle and adipose tissue. DOX treatment led to significant white adipose tissue (WAT) loss (74%) and moderate skeletal muscle loss (Gastrocnemius (GAS): 10%), along with decreased basal activity (53%) and energy expenditure (27%). A trend toward a reduced type IIa fiber cross-sectional area and a fast-to-slow fiber type switch in the Soleus muscle was observed. The WAT of DOX-treated mice displayed reduced Pparg (p < 0.0001), Cd36 (p < 0.0001) and Glut4 (p < 0.05) mRNA expression—markers of fat and glucose metabolism—compared to controls. In contrast, the GAS of DOX-treated mice showed increased Cd36 (p < 0.05) and Glut4 (p < 0.01), together with elevated Pdk4 (p < 0.001) mRNA expression—suggesting reduced carbohydrate oxidation—compared to controls. Additionally, DOX increased Murf1 (p < 0.05) and Atrogin1 (p < 0.05) mRNA expression—markers of protein degradation—compared to controls. In both the WAT and GAS of DOX-treated mice, Ppard mRNA expression remained unchanged. Overall, DEXRA failed to prevent these DOX-induced changes. Collectively, our results suggest that DOX induced varying degrees of wasting in adipose tissue and skeletal muscle, driven by distinct mechanisms. While DEXRA protected against DOX-induced CTRCD, it did not counteract its adverse effects on skeletal muscle and adipose tissue.

The mechanism underlying myopericarditis associated with mRNA COVID-19 vaccination, including increased susceptibility in young males, remains poorly understood. This study aims to explore the hypothesis that engaging in physical exercise at the time of mRNA COVID-19 vaccination may promote a cardiac inflammatory response, leading to the development of myopericarditis. Male BALB/c mice underwent treadmill running or remained sedentary for five weeks. Subsequently, two doses of the Pfizer/BioNTech vaccine or vehicle were administered with a 14-day interval, while the exercise regimen continued. The animals were euthanized days after the second vaccination. Vaccination was followed by body weight loss, increased hepatic inflammation, and an antigen-specific T cell response. Small foci of fibrovascular inflammation and focal cell loss were observed in the right ventricle, irrespective of vaccination and/or exercise. Vaccination did not elevate cardiac troponin levels. Cardiac tissue from the vaccinated mice showed upregulated mRNA expression of the genes IFNγ and IL-1β, but not IL-6 or TNFα. This pro-inflammatory signature in the heart was not exacerbated by endurance exercise. Ex vivo vascular reactivity remained unaffected by vaccination. Our data provide evidence for the cardiac safety of mRNA COVID-19 vaccination. The role of exercise in the development of pro-inflammatory cardiac changes post mRNA vaccination could not be established.

Recent studies have shown that heart failure (HF) and left ventricular (LV) dysfunction are associated with enhanced tumor growth. However, whether treating LV dysfunction mitigates its impact on cancer progression remains unknown. We hypothesized that HF treatments would attenuate tumor growth in a rodent model of post-myocardial infarction (MI)-induced LV dysfunction, and that different pharmacological agents (carvedilol, enalapril, and empagliflozin) might exert distinct effects on tumor progression. MI was induced in female BALB/c mice, leading to LV dysfunction. Mice with LV ejection fraction < 40% two weeks after MI received daily vehicle or one of three HF treatments by gavage. Two weeks later, 2 × 105 4T1 metastatic breast cancer cells were injected, with a three-week follow-up. The effects of HF treatments on cancer progression were assessed by analyzing: (i) tumor size in vivo over 22 days, (ii) lung metastasis development and (iii) gene expression levels in tumor tissue by RNA sequencing. Enalapril reversed several MI-induced transcriptomic changes in tumor tissue. Empagliflozin reduced primary tumor growth, while carvedilol reduced metastatic clusters. These effects were absent in control mice without MI, and neither drug directly affected cultured 4T1 cells. Transcriptomic analysis revealed treatment-specific inflammatory pathway regulation. Notably, carvedilol and empagliflozin restored MI-suppressed IFN-γ expression in tumors, accompanied by increased STAT1 expression in 4T1 cells. Specific HF treatments can mitigate cancer growth in a mouse model of MI-induced LV dysfunction, with outcomes varying by treatment. These benefits occurred only with LV dysfunction, suggesting they result from changes in HF pathophysiology rather than direct drug effects on tumor cells. Restoration of immune signaling may contribute to these effects.