Evaluation of eXIA 160XL cardiac‐related enhancement in C57BL/6 and BALB/c mice using micro‐CT

Evaluation of cardiovascular function in mice using micro‐CT requires that a contrast agent be administered to differentiate the blood from the myocardium. eXIA 160XL, an aqueous colloidal poly‐disperse contrast agent with a high iodine concentration (160 mg I ml^?1), creates strong contrast between blood and tissue with a low injection volume. In this study, the blood‐pool enhancement time‐course of eXIA 160XL is monitored over a 48 h period to determine its optimal use during cardiac function studies in C57BL/6 and BALB/c mice. Eight‐second scans were performed (80 kV_p, 110 mA) using the GE Locus Ultra micro‐CT scanner. Six C57BL/6 and six BALB/c male mice (22–24 g) were injected via tail vein with 5 µl g^?1 body weight eXIA 160XL. A precontrast scan was performed; following injection, mice were scanned at 5, 15, 30, 45 and 60 min, and 2, 4, 8, 12, 24 and 48 h. Images were reconstructed, and enhancement–time curves were generated for each of the following tissues: left ventricle (LV), myocardium, liver, spleen, renal cortex, bladder and brown adipose tissue. The highest contrast in the LV occurred at 5 min in both strains (~670 HU above precontrast value). Uptake of the contrast agent by the myocardium was also observed: myocardial tissue showed increasing enhancement over a 4 h period in both strains, remaining even once the contrast was eliminated from the vasculature. In both C57BL/6 and BALB/c strains, eXIA 160XL provided high contrast between blood and myocardial tissue for a period of 30 min following injection. Notably, this contrast agent was also taken up by the myocardium and provided continued enhancement when it was eliminated from the blood, making LV wall motion studies possible. In conclusion, eXIA 160XL, with its high iodine concentration and targeted tissue uptake characteristics, is an ideal agent to use when evaluating cardiovascular function in mice. Copyright © 2012 John Wiley & Sons, Ltd.     

Course and Survival of COVID-19 Patients with Comorbidities in Relation to the Trace Element Status at Hospital Admission

Selenium (Se) and zinc (Zn) are essential trace elements needed for appropriate immune system responses, cell signalling and anti-viral defence. A cross-sectional observational study was conducted at two hospitals in Ghent, Belgium, to investigate whether Se and/or Zn deficiency upon hospital admission correlates to disease severity and mortality risk in COVID-19 patients with or without co-morbidities. Trace element concentrations along with additional biomarkers were determined in serum or plasma and associated to disease severity and outcome. An insufficient Se and/or Zn status upon hospital admission was associated with a higher mortality rate and a more severe disease course in the entire study group, especially in the senior population. In comparison to healthy European adults, the patients displayed strongly depressed total Se (mean ± SD: 59.2 ± 20.6 vs. 84.4 ± 23.4 µg L⁻¹) and SELENOP (mean ± SD: 2.2 ± 1.9 vs. 4.3 ± 1.0 mg L⁻¹) concentrations at hospital admission. Particularly strong associations were observed for death risk of cancer, diabetes and chronic cardiac disease patients with low Se status, and of diabetes and obese patients with Zn deficiency. A composite biomarker based on serum or plasma Se, SELENOP and Zn at hospital admission proved to be a reliable tool to predict severe COVID-19 course and death, or mild disease course. We conclude that trace element assessment at hospital admission may contribute to a better stratification of patients with COVID-19 and other similar infectious diseases, support clinical care, therapeutic interventions and adjuvant supplementation needs, and may prove of particular relevance for patients with relevant comorbidities.     

Three‐dimensional imaging of the mouse heart and vasculature using micro‐CT and whole‐body perfusion of iodine or phosphotungstic acid

Recent studies have investigated histological staining compounds as micro‐computed tomography (micro‐CT) contrast agents, delivered by soaking tissue specimens in stain and relying on passive diffusion for agent uptake. This study describes a perfusion approach using iodine or phosphotungstic acid (PTA) stains, delivered to an intact mouse, to capitalize on the microvasculature as a delivery conduit for parenchymal staining and direct contact for staining artery walls. Twelve C57BL/6 mice, arterially perfused with either 25% Lugol's solution or 5% PTA solution were scanned intact and reconstructed with 26 µm isotropic voxels. The animals were fixed and the heart and surrounding vessels were excised, embedded and scanned; isolated heart images were reconstructed with 13 µm isotropic voxels. Myocardial enhancement and artery diameters were measured. Both stains successfully enhanced the myocardium and vessel walls. Interestingly, Lugol's solution provided a significantly higher enhancement of the myocardium than PTA [2502 ± 437 vs 656 ± 178 Hounsfield units (HU); p < 0.0001], delineating myofiber architecture and orientation. There was no significant difference in vessel wall enhancement (Lugol's, 1036 ± 635 HU; PTA, 738 ± 124 HU; p = 0.29), but coronary arteries were more effectively segmented from the PTA‐stained hearts, enabling segmented imaging of fifth‐ order coronary artery branches. The combination of whole mouse perfusion delivery and use of heavy metal‐containing stains affords high‐resolution imaging of the mouse heart and vasculature by micro‐CT. The differential imaging patterns of Lugol's‐ and PTA‐stained tissues reveals new opportunities for micro‐analyses of cardiac and vascular tissues. Copyright © 2014 John Wiley & Sons, Ltd.     

Increases in condomless chemsex associated with HIV acquisition in MSM but not heterosexuals attending a HIV testing center in Antwerp,Belgium

Background

It has been speculated that the prevalence of chemsex is increasing in men who have sex with men and that this may be playing a role in the spread of HIV.

Methods

We assessed if the prevalence of reported chemsex was increasing and if chemsex was associated with HIV infection in clients attending the ‘Helpcenter’, Antwerp, between 2011 and 2017. This is a HIV/STI testing center that offers HIV/STI testing to HIV-uninfected individuals from key populations including MSM.

Results

We found an increase in the reporting of condomless sex associated with the use of a number of drugs, including ecstasy, amphetamines, GHB and cocaine in MSM (from 8 to 17%) but not in heterosexuals. Reporting condomless chemsex was associated with HIV infection (adjusted odds ratio 5.7 [95% confidence interval 3.2–10.4]).

Conclusions

Our findings provide further evidence of the importance of asking MSM clients about the use of psychoactive substances during consultations and tailoring interventions such as pre exposure prophylaxis, more frequent STI screening and substance abuse counseling accordingly.