Exosome: The Regulator of the Immune System in Sepsis

Unveiling the Role of Exosomes in the Pathophysiology of Sepsis: Insights into Organ Dysfunction and Potential Biomarkers

Extracellular vesicles (EVs) are tools for intercellular communication, mediating molecular transport processes. Emerging studies have revealed that EVs are significantly involved in immune processes, including sepsis. Sepsis, a dysregulated immune response to infection, triggers systemic inflammation and multi-organ dysfunction, posing a life-threatening condition. Although extensive research has been conducted on animals, the complex inflammatory mechanisms that cause sepsis-induced organ failure in humans are still not fully understood. Recent studies have focused on secreted exosomes, which are small extracellular vesicles from various body cells, and have shed light on their involvement in the pathophysiology of sepsis. During sepsis, exosomes undergo changes in content, concentration, and function, which significantly affect the metabolism of endothelia, cardiovascular functions, and coagulation. Investigating the role of exosome content in the pathogenesis of sepsis shows promise for understanding the molecular basis of human sepsis. This review explores the contributions of activated immune cells and diverse body cells' secreted exosomes to vital organ dysfunction in sepsis, providing insights into potential molecular biomarkers for predicting organ failure in septic shock.

Proteomic profiling of serum exosomes reveals acute phase response and promotion of inflammatory and platelet activation pathways in patients with heat stroke

Background: The pathological mechanism of heat stroke (HS) involves the acute phase response, unbalanced immunological/inflammatory reactions, and coagulation initiation, especially platelet activation. Although exosomes contain proteins involved in these biological processes, their protein cargo levels and potential roles in HS remain unknown. This study explored the serum exosome protein expression patterns after HS and their potential roles in the pathogenesis of HS. Methods: Blood samples were collected from ten patients diagnosed with HS upon admission to the intensive care unit (six with severe HS and four with mild HS). Samples from six healthy volunteers were included as control. Using ultracentrifugation, exosomes were prudently isolated, and their protein contents were profiled using liquid chromatography-tandem mass spectrometry analysis with isobaric tags for relative and absolute quantification-based proteomics. Results: Compared with healthy volunteers, patients with HS showed significant changes in the levels of 33 exosomal proteins (23 upregulated and 10 downregulated). The most upregulated proteins included serum amyloid A-1 (SAA-1), von Willebrand factor (vWF), S100A8, and histone H3. In addition, SAA-1, vWF, platelet membrane glycoprotein, S100A8, and histone H3 were more enriched in the exosomes from patients with severe HS than from those with mild HS. Gene ontology analysis revealed that the HS-modulated exosomal proteins were mostly related to inflammatory response, including the acute-phase response, platelet activation/degranulation, and innate immune response. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed significant enrichment of proteins in the IL-17 signaling pathway, platelet activation, neutrophil extracellular trap formation, Fc epsilon RI signaling pathway, chemokine signaling pathway, and NOD-like receptor signaling pathway, among others. Several serum exosomal proteins, including SAA-1, vWF, and S100A8, which are related to the acute phase, inflammatory response, and platelet activation, were confirmed to be elevated in patients with HS, and were significantly correlated with disease severity, organ dysfunction, and death. Conclusion: Overall, this study explores the potential role of the serum exosomal proteome in the inflammatory response and platelet activation in HS, suggests the pathological mechanisms underlying HS-induced injuries, and recommends reliable exosomal biomarkers for predicting HS prognosis.

Immunomodulatory function of licensed human bone marrow mesenchymal stromal cell-derived apoptotic bodies

BACKGROUND

Mesenchymal stromal cells (MSCs) show great potential for immunomodulatory and anti-inflammatory treatments. Clinical trials have been performed for the treatment of Type 1 diabetes, graft-versus-host disease and organ transplantation, which offer a promise of MSCs as an immunomodulatory therapy. Nevertheless, their unstable efficacy and immunogenicity concerns present challenges to clinical translation. It has emerged that the MSC-derived secretome, which includes secreted proteins, exosomes, apoptotic bodies (ABs) and other macromolecules, may have similar therapeutic effects to parent MSCs. Among all of the components of the MSC-derived secretome, most interest thus far has been garnered by exosomes for their therapeutic potential. However, since MSCs were reported to undergo apoptosis after in vivo transplantation and release ABs, we speculated as to whether ABs have immunomodulatory effects. In this study, cytokine licensing was used to enhance the immunomodulatory potency of MSCs and ABs derived from licensed MSCs in vitro were isolated to explore their immunomodulatory effects as an effective non-viable cell therapy.

RESULTS

IFN-γ and IFN-γ/TGF-β1 licensing enhanced the immunomodulatory effect of MSCs on T cell proliferation. Further, TGF-β1 and IFN-γ licensing strengthened the immunomodulatory effect of MSC on reducing the TNF-α and IL-1β expression by M1 macrophage-like THP-1 cells. Additionally, we discovered the immunomodulatory effect mediated by MSC-derived apoptotic bodies. Licensing impacted the uptake of ABs by recipient immune cells and importantly altered their phenotypes.

CONCLUSION

ABs derived from IFN-γ/TGF-β1-licensed apoptotic MSCs significantly inhibited T cell proliferation, induced more regulatory T cells, and maintained immunomodulatory T cells but reduced pro-inflammatory T cells.

Neuroinflammation: The central enabler of postoperative cognitive dysfunction

The proportion of advanced age patients undergoing surgical procedures is on the rise owing to advancements in surgical and anesthesia technologies as well as an overall aging population. As a complication of anesthesia and surgery, older patients frequently suffer from postoperative cognitive dysfunction (POCD), which may persist for weeks, months or even longer. POCD is a complex pathological process involving multiple pathogenic factors, and its mechanism is yet unclear. Potential theories include inflammation, deposition of pathogenic proteins, imbalance of neurotransmitters, and chronic stress. The identification, prevention, and treatment of POCD are still in the exploratory stages owing to the absence of standardized diagnostic criteria. Undoubtedly, comprehending the development of POCD remains crucial in overcoming the illness. Neuroinflammation is the leading hypothesis and a crucial component of the pathological network of POCD and may have complex interactions with other mechanisms. In this review, we discuss the possible ways in which surgery and anesthesia cause neuroinflammation and investigate the connection between neuroinflammation and the development of POCD. Understanding these mechanisms may likely ensure that future treatment options of POCD are more effective.

Nanotherapeutics with immunoregulatory functions for the treatment of bacterial infection

The advent of drug-resistant pathogens results in the occurrence of stubborn bacterial infections that cannot be treated with traditional antibiotics. Antibacterial immunotherapy by reviving or activating the body's immune system to eliminate pathogenic bacteria has confirmed promising therapeutic strategies in controlling bacterial infections. Subsequent studies found that antimicrobial immunotherapy has its own benefits and limitations, such as avoiding recurrence of infection and autoimmunity-induced side effects. Current studies indicate that the various antibacterial therapeutic strategies inducing immune regulation can achieve superior therapeutic efficacy compared with monotherapy alone. Therefore, summarizing the recent advances in nanomedicine with immunomodulatory functions for combating bacterial infections is necessary. Herein, we briefly introduce the crisis caused by drug-resistant bacteria and the opportunity for antibacterial immunotherapy. Then, immune-involved multimodal antibacterial therapy for the treatment of infectious diseases was systematically summarized. Finally, the prospects and challenges of immune-involved combinational therapy are discussed.

Comparison of immunotherapy mediated by apoptotic bodies, microvesicles and exosomes: apoptotic bodies' unique anti-inflammatory potential

Immunotherapy, including immunostimulation and immunosuppression, has seen significant development in the last 10 years. Immunostimulation has been verified as effective in anti-cancer treatment, while immunosuppression is used in the treatment of autoimmune disease and inflammation. Currently, with the update of newly-invented simplified isolation methods and the findings of potent triggered immune responses, extracellular vesicle-based immunotherapy is very eye-catching. However, the research on three main types of extracellular vesicles, exosomes, microvesicles and apoptotic bodies, needs to be more balanced. These three subtypes share a certain level of similarity, and at the same time, they have their own properties caused by the different methods of biogensis. Herein, we summarized respectively the status of immunotherapy based on each kind of vesicle and discuss the possible involved mechanisms. In conclusion, we highlighted that the effect of the apoptotic body is clear and strong. Apoptotic bodies have an excellent potential in immunosuppressive and anti-inflammatory therapies .

Potential of extracellular vesicles for early prediction of severity and potential risk stratification in critical inflammatory diseases

Some acute inflammatory diseases are often exacerbated during or after hospitalization, leading to some severe manifestations like systemic inflammatory response syndrome, multiple organ failure, and high mortality. Early clinical predictors of disease severity are urgently needed to optimize patient management for better prognosis. The existing clinical scoring system and laboratory tests cannot circumvent the problems of low sensitivity and limited specificity. Extracellular vesicles (EVs) are heterogeneous nanosecretory vesicles containing various biomolecules related to immune regulation, inflammation activation, and inflammation-related complications. This review provides an overview of EVs as inflammatory mediators, inflammatory signaling pathway regulators, promoters of inflammatory exacerbation, and markers of severity and prognosis. Currently, although relevant biomarkers are clinically available or are in the preclinical research stage, searching for new markers and detection methods is still warranted, as the problems of low sensitivity/specificity, cumbersome laboratory operation and high cost still plague clinicians. In-depth study of EVs might open a door in the search for novel predictors.

Can exosomes transfer the preconditioning effects triggered by (poly)phenol compounds between cells?

Effective strategies in prolonging life- and health span are increasingly recognized as acting as mild stressors. Micronutrients and other dietary compounds such as (poly)phenols may act as moderate stressors and confer protective effects via a preconditioning phenomenon. (Poly)phenols and their metabolites may not need to reach their target cells to produce biologically significant responses, so that cells exposed to it at entry points may communicate signals to other cells. One of such "communication" mechanisms could occur through extracellular vesicles, including exosomes. In vitro loading of exosomes with (poly)phenols has been used to achieve targeted exosome homing. However, it is unknown if similar shuttling phenomena occur in vivo upon (poly)phenols consumption. Alternatively, exposure to (poly)phenols might trigger responses in exposed organs, which can subsequently signal to cells distant from exposure sites via exosomes. The currently available studies favor indirect effects of (poly)phenols, tempting to suggest a "billiard-like" or "domino-like" propagating effect mediated by quantitative and qualitative changes in exosomes triggered by (poly)phenols. In this review, we discuss the limited current data available on how (poly)phenols exposure can potentially modify exosomes activity, highlighting major questions regarding how (epi)genetic, physiological, and gut microbiota factors can modulate and be modulated by the putative exosome-(poly)phenolic compound interplay that still remains to be fully understood.

Bone Marrow Mesenchymal Stem Cells (BMSC) from Exosome with High miR-184 Level Ameliorates Sepsis

This study assesses whether BMSC from exosome with high miR-184 level ameliorates sepsis. BMSC with high miR-184 expression established. RAW264.7 cells were cultivated in vitro and divided into control set, model set, BMSC set and BMSC with high miR-184 level set. The model was established through infection of RAW264.7 cells with LPS followed by analysis of cell proliferation and apoptosis, activity of ROS and SOD, secretion of IL-1β, IL-6 and TNF-α as well as the expression of NF-κB and TRAIL. BMSC set showed significantly upregulated miR-184 expression, increased cell proliferation and SOD activity, reduced ROS activity, decreased secretion of IL-1β, IL-6 and TNF-α as well as the expression of NF-κB and TRAIL. The above changes were more significant in the set of BMSC with overexpression of miR-184. In conclusion, cell proliferation, apoptosis and inflammation in RAW264.7 cells induced with LPS is regulated by BMSC from exosome with high expression of miR-184, which is possibly through restraining the NF-κB and TRAIL and oxidative stress.

Concise review: Current understanding of extracellular vesicles to treat neuropathic pain

Extracellular vesicles (EVs) including exosomes are vesicular vesicles with phospholipid bilayer implicated in many cellular interactions and have the ability to transfer multiple types of cargo to cells. It has been found that EVs can package various molecules including proteins and nucleic acids (DNA, mRNA, and noncoding RNA). The discovery of EVs as carriers of proteins and various forms of RNA, such as microRNAs (miRNA) and long noncoding RNAs (lncRNA), has raised great interest in the field of drug delivery. Despite the underlying mechanisms of neuropathic pain being unclear, it has been shown that uncontrolled glial cell activation and the neuroinflammation response to noxious stimulation are important in the emergence and maintenance of neuropathic pain. Many studies have demonstrated a role for noncoding RNAs in the pathogenesis of neuropathic pain and EVs may offer possibilities as carriers of noncoding RNAs for potential in neuropathic pain treatment. In this article, the origins and clinical application of EVs and the mechanism of neuropathic pain development are briefly introduced. Furthermore, we demonstrate the therapeutic roles of EVs in neuropathic pain and that this involve vesicular regulation of glial cell activation and neuroinflammation.

Hypoxia-Induced miR-210 Promotes Endothelial Cell Permeability and Angiogenesis via Exosomes in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Exosomes have been proven to play important diagnostic, regulatory, or communication roles in tumorigenesis, tumor progression, or metastasis; in recent studies, lots of molecules, including miRNAs, were found to be aberrantly expressed in tumor exosomes and were correlated with tumor development. However, studies about the expression, relationship, or control mechanisms of miRNAs in exosomes in pancreatic ductal adenocarcinoma (PDAC) are scarce and urgently needed. The aim of this article was to identify and investigate abnormally expressed miRNAs in PDAC exosomes in vivo and in vitro.

METHODS

Microarray studies were used to detect aberrantly expressed miRNAs in PDAC exosomes, and miR-210 expression in cells or exosomes was further analyzed by qRT-PCR. Bioinformatics analyses, dual-luciferase assays, WB, and other assays were utilized to explore the miRNA molecular mechanisms. The living cell coculture model and immunofluorescence analysis were employed to image the communication between PDAC cells and endothelial cells. Other biological experiments in the study include a real-time intravital imaging system, EdU, transwell, xenograft models, and so on.

RESULTS

miR-210 is significantly expressed in PDAC exosomes and malignant cells. High miR-210 significantly facilitated tumor angiogenesis, cell invasion, and proliferation in PDAC cells. Further mechanistic detection revealed that miR-210 negatively regulated EFNA3 expression and participated in the PI3K/AKT/VEGFA or Wnt/Β-catenin/RHOA pathways, thus promoting tumor angiogenesis and cellular permeability. PDAC cells promote endothelial angiogenesis or permeability via miR-210 transmission by tumor exosomes. Exosomal miR-210 promotes PDAC progression in vivo. Further detection of PDAC plasma exosomal miR-210 suggests that exosomal miR-210 expression was high and significantly associated with vascular invasion and TNM stage and was an independent risk factor for PDAC overall survival.

CONCLUSIONS

PDAC cell-secreted exosomes could promote angiogenesis and cellular permeability of neighboring endothelial angiogenesis or permeability via miR-210 transmission. Exosomal miR-210 may play important roles in tumor biology and may be a useful prognostic marker in PDAC.

Engineered Extracellular Vesicles in Treatment of Type 1 Diabetes Mellitus: A Prospective Review

Insulin replacement is an available treatment for autoimmune type 1 diabetes mellitus (T1DM). There are multiple limitations in the treatment of autoimmune diseases such as T1DM by immunosuppression using drugs and chemicals. The advent of extracellular vesicle (EV)-based therapies for the treatment of various diseases has attracted much attention to the field of bio-nanomedicine. Tolerogenic nanoparticles can induce immune tolerance, especially in autoimmune diseases. EVs can deliver cargo to specific cells without restrictions. Accordingly, EVs can be used to deliver tolerogenic nanoparticles, including iron oxide-peptide-major histocompatibility complex, polyethylene glycol-silver-2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester, and carboxylated poly (lactic-co-glycolic acid) nanoparticles coupled with or encapsulating an antigen, to effectively treat autoimmune T1DM. The present work highlights the advances in exosome-based delivery of tolerogenic nanoparticles for the treatment of autoimmune T1DM.

Exosomes─Nature's Lipid Nanoparticles, a Rising Star in Drug Delivery and Diagnostics

Exosomes are a subgroup of nanosized extracellular vesicles enclosed by a lipid bilayer membrane and secreted by most eukaryotic cells. They represent a route of intercellular communication and participate in a wide variety of physiological and pathological processes. The biological roles of exosomes rely on their bioactive cargos, including proteins, nucleic acids, and lipids, which are delivered to target cells. Their distinctive properties─innate stability, low immunogenicity, biocompatibility, and good biomembrane penetration capacity─allow them to function as superior natural nanocarriers for efficient drug delivery. Another notably favorable clinical application of exosomes is in diagnostics. They hold various biomolecules from host cells, which are indicative of pathophysiological conditions; therefore, they are considered vital for biomarker discovery in clinical diagnostics. Here, we use data from the CAS Content Collection and provide a landscape overview of the current state and delineate trends in research advancement on exosome applications in therapeutics and diagnostics across time, geography, composition, cargo loading, and development pipelines. We discuss exosome composition and pathway, from their biogenesis and secretion from host cells to recipient cell uptake. We assess methods for exosome isolation and purification, their clinical applications in therapy and diagnostics, their development pipelines, the exploration goals of the companies, the assortment of diseases they aim to treat, development stages of their research, and publication trends. We hope this review will be useful for understanding the current knowledge in the field of medical applications of exosomes, in an effort to further solve the remaining challenges in fulfilling their potential.

Dual Role of Extracellular Vesicles in Sepsis-Associated Kidney and Lung Injury

Extracellular vesicles form a complex intercellular communication network, shuttling a variety of proteins, lipids, and nucleic acids, including regulatory RNAs, such as microRNAs. Transfer of these molecules to target cells allows for the modulation of sets of genes and mediates multiple paracrine and endocrine actions. EVs exert broad pro-inflammatory, pro-oxidant, and pro-apoptotic effects in sepsis, mediating microvascular dysfunction and multiple organ damage. This deleterious role is well documented in sepsis-associated acute kidney injury and acute respiratory distress syndrome. On the other hand, protective effects of stem cell-derived extracellular vesicles have been reported in experimental models of sepsis. Stem cell-derived extracellular vesicles recapitulate beneficial cytoprotective, regenerative, and immunomodulatory properties of parental cells and have shown therapeutic effects in experimental models of sepsis with kidney and lung involvement. Extracellular vesicles are also likely to play a role in deranged kidney-lung crosstalk, a hallmark of sepsis, and may be key to a better understanding of shared mechanisms underlying multiple organ dysfunction. In this review, we analyze the state-of-the-art knowledge on the dual role of EVs in sepsis-associated kidney/lung injury and repair. PubMed library was searched from inception to July 2022, using a combination of medical subject headings (MeSH) and keywords related to EVs, sepsis, acute kidney injury (AKI), acute lung injury (ALI), and acute respiratory distress syndrome (ARDS). Key findings are summarized into two sections on detrimental and beneficial mechanisms of actions of EVs in kidney and lung injury, respectively. The role of EVs in kidney-lung crosstalk is then outlined. Efforts to expand knowledge on EVs may pave the way to employ them as prognostic biomarkers or therapeutic targets to prevent or reduce organ damage in sepsis.

Dynamic immune and exosome transcriptomic responses in patients undergoing psychostimulant methamphetamine withdrawal

Methamphetamine (METH) addiction and withdrawal cause serious harm to both the immune system and nervous system. However, the pathogenesis remains largely unknown. Herein, we investigated the peripheral cytokines and exosomal transcriptome regulatory networks in the patients with METH use disorders (MUDs) undergoing withdrawal. Twenty-seven cytokines were simultaneously assessed in 51 subjects, including 22 at the acute withdrawal (AW) stage and 29 at the protracted withdrawal (PW) stage, and 31 age and gender-matched healthy controls (HCs). Compared to the HCs, significantly decreased levels of interleukin (IL)-1β, IL-9, IL-15, Basic FGF, and MIP1a, increased levels of IL-1rα, IL-6, Eotaxin IP-10, VEGF, and RANTES were identified in AW. These disturbances were mostly or partly restored to the baseline in PW. However, the cytokines IL-6, IL-7, and IL-12p70 were consistently increased even after one year of withdrawal. Besides, a significant decrease in CD3+T and CD4+T cell numbers was observed in AW, and the diminishment was restored to baseline in PW. Comparatively, there were no statistically significant changes in CD8+T, NK, and B cells. Furthermore, the exosomal mRNAs and long non-coding RNAs (lncRNA) were profiled, and the lncRNA-miRNA-mRNA networks were constructed and associated with METH AW and PW stages. Notably, the chemokine signaling was remarkably upregulated during AW. By contrast, the differentially expressed mRNAs/lincRNAs were significantly enriched in neurodegeneration-related diseases. Taken together, a group of METH withdrawal-related cytokines and exosomal mRNA/lncRNA regulatory networks were obtained, which provides a useful experimental and theoretical basis for further understanding of the pathogenesis of the withdrawal symptoms in MUDs.

High Mobility Group Proteins in Sepsis

Sepsis, a systemic inflammatory response disease, is the most severe complication of infection and a deadly disease. High mobility group proteins (HMGs) are non-histone nuclear proteins binding nucleosomes and regulate chromosome architecture and gene transcription, which act as a potent pro-inflammatory cytokine involved in the delayed endotoxin lethality and systemic inflammatory response. HMGs increase in serum and tissues during infection, especially in sepsis. A growing number of studies have demonstrated HMGs are not only cytokines which can mediate inflammation, but also potential therapeutic targets in sepsis. To reduce sepsis-related mortality, a better understanding of HMGs is essential. In this review, we described the structure and function of HMGs, summarized the definition, epidemiology and pathophysiology of sepsis, and discussed the HMGs-related mechanisms in sepsis from the perspectives of non-coding RNAs (microRNA, long non-coding RNA, circular RNA), programmed cell death (apoptosis, necroptosis and pyroptosis), drugs and other pathophysiological aspects to provide new targets and ideas for the diagnosis and treatment of sepsis.

Extracellular Vesicles Released from Stem Cells as a New Therapeutic Strategy for Primary and Secondary Glomerulonephritis

Current treatment of primary and secondary glomerulopathies is hampered by many limits and a significant proportion of these disorders still evolves towards end-stage renal disease. A possible answer to this unmet challenge could be represented by therapies with stem cells, which include a variety of progenitor cell types derived from embryonic or adult tissues. Stem cell self-renewal and multi-lineage differentiation ability explain their potential to protect and regenerate injured cells, including kidney tubular cells, podocytes and endothelial cells. In addition, a broad spectrum of anti-inflammatory and immunomodulatory actions appears to interfere with the pathogenic mechanisms of glomerulonephritis. Of note, mesenchymal stromal cells have been particularly investigated as therapy for Lupus Nephritis and Diabetic Nephropathy, whereas initial evidence suggest their beneficial effects in primary glomerulopathies such as IgA nephritis. Extracellular vesicles mediate a complex intercellular communication network, shuttling proteins, nucleic acids and other bioactive molecules from origin to target cells to modulate their functions. Stem cell-derived extracellular vesicles recapitulate beneficial cytoprotective, reparative and immunomodulatory properties of parental cells and are increasingly recognized as a cell-free alternative to stem cell-based therapies for different diseases including glomerulonephritis, also considering the low risk for potential adverse effects such as maldifferentiation and tumorigenesis. We herein summarize the renoprotective potential of therapies with stem cells and extracellular vesicles derived from progenitor cells in glomerulonephritis, with a focus on their different mechanisms of actions. Technological progress and growing knowledge are paving the way for wider clinical application of regenerative medicine to primary and secondary glomerulonephritis: this multi-level, pleiotropic therapy may open new scenarios overcoming the limits and side effects of traditional treatments, although the promising results of experimental models need to be confirmed in the clinical setting.

Emerging role of exosomes in the pathology of chronic obstructive pulmonary diseases; destructive and therapeutic properties

Chronic obstructive pulmonary disease (COPD) is known as the third leading cause of human death globally. Enhanced chronic inflammation and pathological remodeling are the main consequences of COPD, leading to decreased life span. Histological and molecular investigations revealed that prominent immune cell infiltration and release of several cytokines contribute to progressive chronic remodeling. Recent investigations have revealed that exosomes belonging to extracellular vesicles are involved in the pathogenesis of COPD. It has been elucidated that exosomes secreted from immune cells are eligible to carry numerous pro-inflammatory factors exacerbating the pathological conditions. Here, in this review article, we have summarized various and reliable information about the negative role of immune cell-derived exosomes in the remodeling of pulmonary tissue and airways destruction in COPD patients.

Potential Application of Exosomes in Vaccine Development and Delivery

Exosomes are cell-derived components composed of proteins, lipid, genetic information, cytokines, and growth factors. They play a vital role in immune modulation, cell-cell communication, and response to inflammation. Immune modulation has downstream effects on the regeneration of damaged tissue, promoting survival and repair of damaged resident cells, and promoting the tumor microenvironment via growth factors, antigens, and signaling molecules. On top of carrying biological messengers like mRNAs, miRNAs, fragmented DNA, disease antigens, and proteins, exosomes modulate internal cell environments that promote downstream cell signaling pathways to facilitate different disease progression and induce anti-tumoral effects. In this review, we have summarized how vaccines modulate our immune response in the context of cancer and infectious diseases and the potential of exosomes as vaccine delivery vehicles. Both pre-clinical and clinical studies show that exosomes play a decisive role in processes like angiogenesis, prognosis, tumor growth metastasis, stromal cell activation, intercellular communication, maintaining cellular and systematic homeostasis, and antigen-specific T- and B cell responses. This critical review summarizes the advancement of exosome based vaccine development and delivery, and this comprehensive review can be used as a valuable reference for the broader delivery science community.

The Concentration of Large Extracellular Vesicles Differentiates Early Septic Shock From Infection

Septic shock represents a subset of sepsis with severe physiological aberrations and a higher mortality rate than sepsis alone. Currently, the laboratory tools which can be used to identify the state of septic shock are limited. In pre-clinical studies, extracellular vesicles (EVs), especially large EVs (lEVs), have been demonstrated a role as functional inflammatory mediators of sepsis. However, its longitudinal trend during the disease course has not been explored. In this study, the quantities and subtypes of plasma-derived lEVs were longitudinally compared between patients with septic shock (n = 21) and non-sepsis infection (n = 9), who presented within 48 h of their symptom onset. Blood specimens were collected for seven consecutive days after hospital admission. lEVs quantification and subtyping were performed using an imaging flow cytometer. The experiments revealed a higher lEVs concentration in septic shock patients than infected patients at the onset of the disease. In septic shock patients, lEVs concentration decreased over time as opposed to infected patients whose lEVs concentration is relatively static throughout the study period. The major contributors of lEVs in both septic shock and infected patients were of non-leukocyte origins; platelets, erythrocytes, and endothelial cells released approximately 40, 25, and 15% of lEVs, respectively. Among lEVs of leukocyte origins, neutrophils produced the highest number of EVs. Nevertheless, the proportion of each subtype of lEVs among the given amount of lEVs produced was similar between septic shock and infected patients. These findings raise the possibility of employing lEVs enumeration as a septic shock identifying tool, although larger studies with a more diverse group of participants are warranted to extrapolate the findings to a general population.

Serum C1q Levels Have Prognostic Value for Sepsis and are Related to the Severity of Sepsis and Organ Damage

Objective

To explore the clinical application value of serum complement component C1q levels in sepsis.

Methods

The clinical data and laboratory examination data of 320 research subjects (including 132 cases as sepsis group, 93 cases as nonsepsis group and 95 cases as control group) who were diagnosed and treated in Renmin Hospital of Wuhan University from July 2020 to March 2021 were collected. We compared the levels of each index among the three groups and further analyzed the C1q levels of different severity subgroups and different outcome subgroups of sepsis. Afterwards, we explored the correlation between C1q levels and SOFA score, organ damage indexes and coagulation indexes. Finally, the receiver operating characteristic curve (ROC) was used to analyze the prognostic value of C1q in patients with sepsis.

Results

C1q levels were significantly reduced in the serum of patients with sepsis; the level of C1q in the death group was lower than that in the survival group (127.1 mg/L vs 153.2 mg/L, P < 0.05), and the mortality in the C1q decreased group was higher when compared with C1q normal group; in addition, serum C1q levels were correlated with SOFA score, organ damage indexes and coagulation indexes; C1q had a high area under the curve (AUC) for the prognosis of sepsis, and the combination of other indexes can further improve the prognostic value.

Conclusion

Serum C1q levels have potential clinical value for the condition and prognosis of sepsis.

Exosomes: Potential Disease Biomarkers and New Therapeutic Targets

Exosomes are extracellular vesicles released by cells, both constitutively and after cell activation, and are present in different types of biological fluid. Exosomes are involved in the pathogenesis of diseases, such as cancer, neurodegenerative diseases, pregnancy disorders and cardiovascular diseases, and have emerged as potential non-invasive biomarkers for the detection, prognosis and therapeutics of a myriad of diseases. In this review, we describe recent advances related to the regulatory mechanisms of exosome biogenesis, release and molecular composition, as well as their role in health and disease, and their potential use as disease biomarkers and therapeutic targets. In addition, the advantages and disadvantages of their main isolation methods, characterization and cargo analysis, as well as the experimental methods used for exosome-mediated drug delivery, are discussed. Finally, we present potential perspectives for the use of exosomes in future clinical practice.