Circulating Endothelial Cells: A New Possible Marker of Endothelial Damage in Kawasaki Disease, Multisystem Inflammatory Syndrome in Children and Acute SARS-CoV-2 Infection

Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vβ21.3+ activation in multi-inflammatory syndrome in children

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vβ21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vβ21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vβ21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells.

Blood-brain barrier biomarkers

The blood-brain barrier (BBB) is a dynamic interface that regulates the exchange of molecules and cells between the brain parenchyma and the peripheral blood. The BBB is mainly composed of endothelial cells, astrocytes and pericytes. The integrity of this structure is essential for maintaining brain and spinal cord homeostasis and protection from injury or disease. However, in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, and multiple sclerosis, the BBB can become compromised thus allowing passage of molecules and cells in and out of the central nervous system parenchyma. These agents, however, can serve as biomarkers of BBB permeability and neuronal damage, and provide valuable information for diagnosis, prognosis and treatment. Herein, we provide an overview of the BBB and changes due to aging, and summarize current knowledge on biomarkers of BBB disruption and neurodegeneration, including permeability, cellular, molecular and imaging biomarkers. We also discuss the challenges and opportunities for developing a biomarker toolkit that can reliably assess the BBB in physiologic and pathophysiologic states.

MRI Diagnosis of Coronary Artery Lesions in Children With Kawasaki Disease and Their Correlation With Inflammatory Factors

BACKGROUND

Ultrasonography (US), as a routine examination for evaluating coronary artery lesions (CAL) in children with Kawasaki disease (KD), has strong subjectivity and limitations. Non-contrast enhanced coronary magnetic resonance angiography (NCE-CMRA) is sensitive and reliable in displaying the segments of coronary arteries (CA).

PURPOSE

To evaluate the CA using NCE-CMRA, to compare NCE-CMRA with US, and to assess the correlation between KD-related inflammatory factors and the occurrence of CAL.

STUDY TYPE

Retrospective.

POPULATION

61 children with KD who had undergone NCE-CMRA. Ultimately, 52 cases were included (32 males and 20 females), with an average of 5.9 ± 0.3 years old.

FIELD STRENGTH/SEQUENCE

3-T, 3D balanced turbo field echo sequence.

ASSESSMENT

NCE-CMRA and US coronary visualization rates were compared in 41 children who were imaged with both techniques. Inflammatory factors were compared between CAL and normal coronary artery (NCA) subgroups. In the CAL group, correlations of these inflammatory factors with CAL parameters were investigated.

STATISTICAL TESTS

Comparison between groups was performed by the two independent samples t-test; the comparison of enumeration data between groups was performed by chi-square test. Receiver operating characteristic (ROC) curve analysis was performed to determine the sensitivity of inflammatory factors for detecting CAL. The correlation between CAL and inflammatory indexes was analyzed by multiple linear regression. A P value <0.05 was considered statistically significant.

RESULTS

NCE-CMRA visualized significantly more segments than US (76% vs. 46%). There were significant differences in PLT, CRP, ESR, and D-dimer between the CAL and NCA groups. ROC curve analysis showed that the sensitivities of these four indicators in diagnosing CAL were 39%, 44%, 72%, and 61%, respectively, at cut-off points of 562.5 × 109 /L, 48.93 mg/L, 45.5 mm/h, and 0.5 mg/L, respectively.

DATA CONCLUSION

The combination of NCE-CMRA and inflammatory factors is helpful for the early diagnosis and disease severity of CAL in children with KD.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Markers of Endothelial Dysfunction in Kawasaki Disease: An Update

Kawasaki disease (KD) is a medium vessel vasculitis that has a special predilection for coronary arteries. Cardiovascular complications include the development of coronary artery abnormalities (CAAs) and myocarditis. Endothelial dysfunction (ED) is now recognized to be a key component in the pathogenesis of KD and is believed to contribute to the development of CAAs. ED has been evaluated by several clinical parameters. However, there is paucity of literature on laboratory markers for ED in KD. The evaluation of ED can be aided by the identification of biomarkers such as oxidative stress markers, circulating cells and their progenitors, angiogenesis factors, cytokines, chemokines, cell-adhesion molecules, and adipokines. If validated in multicentric studies, these biomarkers may be useful for monitoring the disease course of KD. They may also provide a useful predictive marker for the development of premature atherosclerosis that is often a concern during long-term follow-up of KD. This review provides insights into the current understanding of the significance of ED in KD.

High Fatality Rates in Pediatric Multisystem Inflammatory Syndrome: A Multicenter Experience From the Epicenter of Brazil's Coronavirus Pandemic

BACKGROUND

Brazil´s case fatality rate (CFR) of pediatric multisystem inflammatory syndrome in children and adolescents (MIS-C) is among the highest worldwide. Despite these concerns, limited hospital-based and comprehensive pediatric data have been published on MIS-C in Brazilian children.

METHODS

We performed a descriptive analysis of the MIS-C scores in 16 public and private hospitals providing secondary and tertiary care in the metropolitan area of São Paulo, Brazil. Clinical and demographic information were systematically extracted from the electronic medical records of each patient. Logistic regression analysis was performed to identify the combined effects of MIS-C phenotype, disease severity and comorbidity as dependent variables.

RESULTS

A total of 101 patients met the MIS-C criteria and were evaluated. The median age was 67 months, 60% were male, 28.7% were black or afrodescendant and 62.3% were admitted to public hospitals. Underlying medical conditions were observed in 16.8% of patients and were associated with a longer duration of hospitalization. A Kawasaki disease-like phenotype was observed in 43.5% of patients, and they demonstrated a trend of lower median age. Children with severe MIS-C were older (median age 91 months vs. 36 months) and had a nonspecific phenotype, more cardiovascular and respiratory involvement and kidney injury; 73.3% required intensive care, 20.8% required mechanical ventilation and 35.6% required inotropic support. Four deaths occurred (CFR = 3.9%), three of which were in healthy participants.

CONCLUSION

We identified a lower median age, particularly among children with Kawasaki disease-like phenotypes, those with a significant need for intensive care, and a high CFR in MIS-C. Our findings confirmed the increased severity of the disease in the selected Brazilian population.

Preliminary Evidence of the Differential Expression of Human Endogenous Retroviruses in Kawasaki Disease and SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a postinfectious sequela of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with some clinical features overlapping with Kawasaki disease (KD). Our research group and others have highlighted that the spike protein of SARS-CoV-2 can trigger the activation of human endogenous retroviruses (HERVs), which in turn induces inflammatory and immune reactions, suggesting HERVs as contributing factors in COVID-19 immunopathology. With the aim to identify new factors involved in the processes underlying KD and MIS-C, we analysed the transcriptional levels of HERVs, HERV-related genes, and immune mediators in children during the acute and subacute phases compared with COVID-19 paediatric patients and healthy controls. The results showed higher levels of HERV-W, HERV-K, Syn-1, and ASCT-1/2 in KD, MIS-C, and COV patients, while higher levels of Syn-2 and MFSD2A were found only in MIS-C patients. Moreover, KD and MIS-C shared the dysregulation of several inflammatory and regulatory cytokines. Interestingly, in MIS-C patients, negative correlations have been found between HERV-W and IL-10 and between Syn-2 and IL-10, while positive correlations have been found between HERV-K and IL-10. In addition, HERV-W expression positively correlated with the C-reactive protein. This pilot study supports the role of HERVs in inflammatory diseases, suggesting their interplay with the immune system in this setting. The elevated expression of Syn-2 and MFSD2A seems to be a distinctive trait of MIS-C patients, allowing to distinguish them from KD ones. The understanding of pathological mechanisms can lead to the best available treatment for these two diseases, limiting complications and serious outcomes.

Endothelial Cell Response in Kawasaki Disease and Multisystem Inflammatory Syndrome in Children

Although Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) share some clinical manifestations, their cardiovascular outcomes are different, and this may be reflected at the level of the endothelial cell (EC). We performed RNA-seq on cultured ECs incubated with pre-treatment sera from KD (n = 5), MIS-C (n = 7), and healthy controls (n = 3). We conducted a weighted gene co-expression network analysis (WGCNA) using 935 transcripts differentially expressed between MIS-C and KD using relaxed filtering (unadjusted p < 0.05, >1.1-fold difference). We found seven gene modules in MIS-C, annotated as an increased TNFα/NFκB pathway, decreased EC homeostasis, anti-inflammation and immune response, translation, and glucocorticoid responsive genes and endothelial-mesenchymal transition (EndoMT). To further understand the difference in the EC response between MIS-C and KD, stringent filtering was applied to identify 41 differentially expressed genes (DEGs) between MIS-C and KD (adjusted p < 0.05, >2-fold-difference). Again, in MIS-C, NFκB pathway genes, including nine pro-survival genes, were upregulated. The expression levels were higher in the genes influencing autophagy (UBD, EBI3, and SQSTM1). Other DEGs also supported the finding by WGCNA. Compared to KD, ECs in MIS-C had increased pro-survival transcripts but reduced transcripts related to EndoMT and EC homeostasis. These differences in the EC response may influence the different cardiovascular outcomes in these two diseases.

The Biological and Molecular Action of Ozone and Its Derivatives: State-of-the-Art, Enhanced Scenarios, and Quality Insights

The ultimate objective of this review is to encourage a multi-disciplinary and integrated methodological approach that, starting from the recognition of some current uncertainties, helps to deepen the molecular bases of ozone treatment effects on human and animal well-being and to optimize their performance in terms of reproducibility of results, quality, and safety. In fact, the common therapeutic treatments are normally documented by healthcare professionals' prescriptions. The same applies to medicinal gases (whose uses are based on their pharmacological effects) that are intended for patients for treatment, diagnostic, or preventive purposes and that have been produced and inspected in accordance with good manufacturing practices and pharmacopoeia monographs. On the contrary, it is the responsibility of healthcare professionals, who thoughtfully choose to use ozone as a medicinal product, to achieve the following objectives: (i) to understand the molecular basis of the mechanism of action; (ii) to adjust the treatment according to the clinical responses obtained in accordance with the principles of precision medicine and personalized therapy; (iii) to ensure all quality standards.

MIS-C: myths have been debunked, but mysteries remain

Although coronary artery dilation is associated with both multisystem inflammatory syndrome in children (MIS-C) and Kawaski disease, there is currently no evidence of long-term coronary artery damage in MIS-C².

The SARS-CoV-2 spike protein does not seem to act as a superantigen that binds the Vβ-chain of the T cell receptor⁶; the skewing of Vβ21.3 expression on T cells in children with MIS-C is most likely attributable to a non-SARS-CoV-2 related antigen⁷.

The incidence and severity of MIS-C declined during the Omicron wave of the COVID-19 pandemic as compared with earlier waves, although the precise reason for this decline remains to be determined¹⁰.

The role of mitochondria in the pathogenesis of Kawasaki disease

Kawasaki disease is a systemic vasculitis, especially of the coronary arteries, affecting children. Despite extensive research, much is still unknown about the principal driver behind the amplified inflammatory response. We propose mitochondria may play a critical role. Mitochondria serve as a central hub, influencing energy generation, cell proliferation, and bioenergetics. Regulation of these biological processes, however, comes at a price. Release of mitochondrial DNA into the cytoplasm acts as damage-associated molecular patterns, initiating the development of inflammation. As a source of reactive oxygen species, they facilitate activation of the NLRP3 inflammasome. Kawasaki disease involves many of these inflammatory pathways. Progressive mitochondrial dysfunction alters the activity of immune cells and may play a role in the pathogenesis of Kawasaki disease. Because they contain their own genome, mitochondria are susceptible to mutation which can propagate their dysfunction and immunostimulatory potential. Population-specific variants in mitochondrial DNA have also been linked to racial disparities in disease risk and treatment response. Our objective is to critically examine the current literature of mitochondria’s role in coordinating proinflammatory signaling pathways, focusing on potential mitochondrial dysfunction in Kawasaki disease. No association between impaired mitochondrial function and Kawasaki disease exists, but we suggest a relationship between the two. We hypothesize a framework of mitochondrial determinants that may contribute to ethnic/racial disparities in the progression of Kawasaki disease.