Dose Effect of Mesenchymal Stromal Cell Delivery Through Cardiopulmonary Bypass.

BACKGROUND: Neurologic impairments are a significant concern for survivors after pediatric cardiac surgery with cardiopulmonary bypass (CPB). We have previously shown that mesenchymal stromal cell (MSC) delivery through CPB has the potential to mitigate the effects of CPB on neural stem/progenitor cells. This study assessed the dose effects of MSCs. METHODS: Piglets (n = 20) were randomly assigned to 1 of 4 groups: control, CPB, or CPB followed by MSC administration with low and high doses (10 × 106 and 100 × 106 cells per kilogram). We assessed acute dose effect on cell distribution, multiorgan functions, systemic inflammation, microglia activation, and neural stem/progenitor cell activities. RESULTS: By magnetic resonance imaging, approximately 10 times more MSCs were detected within the entire brain after high-dose delivery than after low-dose delivery. No adverse events affecting hemodynamics, various biomarkers, and neuroimaging were detected after high-dose MSC delivery. High-dose MSCs significantly increased circulating levels of interleukin 4 after CPB. Both MSC groups normalized microglia activation after CPB, demonstrating MSC-induced reduction in cerebral inflammation. There was a significant increase in neuroblasts in the subventricular zone in both treatment groups. The thickness of the most active neurogenic area within the subventricular zone was significantly increased after high-dose treatment compared with CPB and low-dose MSCs, suggesting dose-dependent effects on the neurogenic niche. CONCLUSIONS: MSC delivery through CPB is feasible up to 100 × 106 cells per kilogram. MSC treatment during cardiac surgery has the potential to reduce systemic and cerebral inflammation and to modulate responses of an active neurogenic niche to CPB. Further investigation is necessary to assess the long-term effects and to develop a more complete dose-response curve.

Defining the optimal historical control group for a phase 1 trial of mesenchymal stromal cell delivery through cardiopulmonary bypass in neonates and infants.

OBJECTIVE: The Mesenchymal Stromal Cell Delivery through Cardiopulmonary Bypass in Pediatric Cardiac Surgery study is a prospective, open-label, single-centre, dose-escalation phase 1 trial assessing the safety/feasibility of delivering mesenchymal stromal cells to neonates/infants during cardiac surgery. Outcomes will be compared with historical data from a similar population. We aim to define an optimal control group for use in the Mesenchymal Stromal Cell Delivery through Cardiopulmonary Bypass in Pediatric Cardiac Surgery trial. METHODS: Consecutive patients who underwent a two-ventricle repair without aortic arch reconstruction within the first 6 months of life between 2015 and 2020 were studied using the same inclusion/exclusion criteria as the Phase 1 Mesenchymal Stromal Cell Delivery through Cardiopulmonary Bypass in Pediatric Cardiac Surgery trial (n = 169). Patients were allocated into one of three diagnostic groups: ventricular septal defect type, Tetralogy of Fallot type, and transposition of the great arteries type. To determine era effect, patients were analysed in two groups: Group A (2015-2017) and B (2018-2020). In addition to biological markers, three post-operative scoring methods (inotropic and vasoactive-inotropic scores and the Pediatric Risk of Mortality-III) were assessed. RESULTS: All values for three scoring systems were consistent with complexity of cardiac anomalies. Max inotropic and vasoactive-inotropic scores demonstrated significant differences between all diagnosis groups, confirming high sensitivity. Despite no differences in surgical factors between era groups, we observed lower inotropic and vasoactive-inotropic scores in group B, consistent with improved post-operative course in recent years at our centre. CONCLUSIONS: Our studies confirm max inotropic and vasoactive-inotropic scores as important quantitative measures after neonatal/infant cardiac surgery. Clinical outcomes should be compared within diagnostic groupings. The optimal control group should include only patients from a recent era. This initial study will help to determine the sample size of future efficacy/effectiveness studies.

A microarray based approach for the identification of common foodborne viruses.

An oligonucleotide array (microarray) incorporating 13,000 elements representing selected strains of hepatitis A virus (HAV), human coxsackieviruses A and B (CVA and CVB), genogroups I and II of Norovirus (NV), and human rotavirus (RV) gene segments 3,4,10, and 11 was designed based on the principle of tiling. Each oligonucleotide was 29 bases long, starting at every 5th base of every sequence, resulting in an overlap of 24 bases in two consecutive oligonucleotides. The applicability of the array for virus identification was examined using PCR amplified products from multiple HAV and CV strains. PCR products labeled with biotin were hybridized to the array, and the biotin was detected using a brief reaction with Cy3-labeled streptavidin, the array subjected to laser scanning, and the hybridization data plotted as fluorescence intensity against each oligonucleotide in the array. The combined signal intensities of all probes representing a particular strain of virus were calculated and plotted against all virus strains identified on a linear representation of the array. The profile of the total signal intensity identified the strain that is most likely represented in the amplified cDNA target. The results obtained with HAV and CV indicated that the hybridization profile thus generated can be used to identify closely related viral strains. This represents a significant improvement over current methods for virus identification using PCR amplification and amplicon sequencing.

Major structural differences and novel potential virulence mechanisms from the genomes of multiple campylobacter species.

Sequencing and comparative genome analysis of four strains of Campylobacter including C. lari RM2100, C. upsaliensis RM3195, and C. coli RM2228 has revealed major structural differences that are associated with the insertion of phage- and plasmid-like genomic islands, as well as major variations in the lipooligosaccharide complex. Poly G tracts are longer, are greater in number, and show greater variability in C. upsaliensis than in the other species. Many genes involved in host colonization, including racR/S, cadF, cdt, ciaB, and flagellin genes, are conserved across the species, but variations that appear to be species specific are evident for a lipooligosaccharide locus, a capsular (extracellular) polysaccharide locus, and a novel Campylobacter putative licABCD virulence locus. The strains also vary in their metabolic profiles, as well as their resistance profiles to a range of antibiotics. It is evident that the newly identified hypothetical and conserved hypothetical proteins, as well as uncharacterized two-component regulatory systems and membrane proteins, may hold additional significant information on the major differences in virulence among the species, as well as the specificity of the strains for particular hosts.