Sepsis and multiple sclerosis: Causative links and outcomes

How are Long-Covid, Post-Sepsis-Syndrome and Post-Intensive-Care-Syndrome related? A conceptional approach based on the current research literature

Long-Covid (LC), Post-Sepsis-Syndrome (PSS) and Post-Intensive-Care-Syndrome (PICS) show remarkable overlaps in their clinical presentation. Nevertheless, it is unclear if they are distinct syndromes, which may co-occur in the same patient, or if they are three different labels to describe similar symptoms, assigned on the basis on patient history and professional perspective of the treating physician. Therefore, we reviewed the current literature on the relation between LC, PSS and PICS. To date, the three syndromes cannot reliably be distinguished due similarities in clinical presentation as they share the cognitive, psychological and physical impairments with only different probabilities of occurrence and a heterogeneity in individual expression. The diagnosis is furthermore hindered by a lack of specific diagnostic tools. It can be concluded that survivors after COVID-19 sepsis likely have more frequent and more severe consequences than patients with milder COVID-19 courses, and that are some COVID-19-specific sequelae, e.g. an increased risk for venous thromboembolism in the 30 days after the acute disease, which occur less often after sepsis of other causes. Patients may profit from leveraging synergies from PICS, PSS and LC treatment as well as from experiences gained from infection-associated chronic conditions in general. Disentangling molecular pathomechanisms may enable future targeted therapies that go beyond symptomatic treatment.

Screening of four lysosome-related genes in sepsis based on RNA sequencing technology

PURPOSE

Screening of lysosome-related genes in sepsis patients to provide direction for lysosome-targeted therapy.

METHODS

Peripheral blood samples were obtained from 22 patients diagnosed with sepsis and 10 normal controls for the purpose of RNA sequencing and subsequent analysis of differential gene expression. Concurrently, lysosome-related genes were acquired from the Gene Ontology database. The intersecting genes between the differential genes and lysosome-related genes were then subjected to PPI, GO and KEGG analyses. Core genes were identified through survival analysis, and their expression trends in different groups were determined using meta-analysis. Single-cell RNA sequencing was used to clarify the cellular localization of core genes.

RESULTS

The intersection of 1328 sepsis-differential genes with 878 lysosome-related genes yielded 76 genes. PPI analysis showed that intersecting genes were mainly involved in Cellular process, Response to stimulus, Immune system process, Signal transduction, Lysosome. GO and KEGG analysis showed that intersecting genes were mainly involved in leukocyte mediated immunity, cell activation involved in immune response, lytic vacuole, lysosome. Survival analysis screened four genes positively correlated with sepsis prognosis, namely GNLY, GZMB, PRF1 and RASGRP1. The meta-analysis revealed that the expression levels of these four genes were significantly higher in the normal control group compared to the sepsis group, which aligns with the findings from RNA sequencing data. Furthermore, single-cell RNA sequencing demonstrated that T cells and NK cells exhibited high expression levels of GNLY, GZMB, PRF1, and RASGRP1.

CONCLUSION

GNLY, GZMB, PRF1, and RASGRP1, which are lysosome-related genes, are closely linked to the prognosis of sepsis and could potentially serve as novel research targets for sepsis, offering valuable insights for the development of lysosome-targeted therapy. The clinical trial registration number is ChiCTR1900021261, and the registration date is February 4, 2019.

The Lung Microbiome: A New Frontier for Lung and Brain Disease

Due to the limitations of culture techniques, the lung in a healthy state is traditionally considered to be a sterile organ. With the development of non-culture-dependent techniques, the presence of low-biomass microbiomes in the lungs has been identified. The species of the lung microbiome are similar to those of the oral microbiome, suggesting that the microbiome is derived passively within the lungs from the oral cavity via micro-aspiration. Elimination, immigration, and relative growth within its communities all contribute to the composition of the lung microbiome. The lung microbiome is reportedly altered in many lung diseases that have not traditionally been considered infectious or microbial, and potential pathways of microbe-host crosstalk are emerging. Recent studies have shown that the lung microbiome also plays an important role in brain autoimmunity. There is a close relationship between the lungs and the brain, which can be called the lung-brain axis. However, the problem now is that it is not well understood how the lung microbiota plays a role in the disease-specifically, whether there is a causal connection between disease and the lung microbiome. The lung microbiome includes bacteria, archaea, fungi, protozoa, and viruses. However, fungi and viruses have not been fully studied compared to bacteria in the lungs. In this review, we mainly discuss the role of the lung microbiome in chronic lung diseases and, in particular, we summarize the recent progress of the lung microbiome in multiple sclerosis, as well as the lung-brain axis.

Inflammation Controls Susceptibility of Immune-Experienced Mice to Sepsis

Sepsis, an amplified immune response to systemic infection that leads to life-threatening organ dysfunction, affects >125,000 people/day worldwide with 20% mortality. Modest therapeutic progress for sepsis has been made, in part because of the lack of therapeutic translatability between mouse-based experimental models and humans. One potential reason for this difference stems from the extensive use of immunologically naive specific pathogen-free mice in preclinical research. To address this issue, we used sequential infections with well-defined BSL-2 pathogens to establish a novel immune-experienced mouse model (specific pathogen experienced [SPexp]) to determine the extent to which immunological experience and/or inflammation influences the host capacity to respond to subsequent infections, including sepsis. Consistent with their immunological experience, SPexp inbred or outbred mice had significant changes in the composition and activation status of multiple leukocyte populations known to influence the severity of cecal ligation and puncture-induced sepsis. Importantly, by varying the timing of sepsis induction, we found the level of basal inflammation controls sepsis-induced morbidity and mortality in SPexp mice. In addition, although a beneficial role of NK cells in sepsis was recently demonstrated in specific pathogen-free mice, NK cell depletion before cecal ligation and puncture induction in SPexp mice lead to diminished mortality, suggesting NK cells may have beneficial or detrimental roles in the response to septic insult dependent on host immune status. Thus, data highlight the importance of utilizing immune-experienced models for preclinical studies to interrogate the cellular/molecular mechanism(s) that could be therapeutically exploited during severe and dysregulated infection-induced inflammatory responses, such as sepsis.