Elevated Circulatory Levels of Microparticles Are Associated to Lung Fibrosis and Vasculopathy During Systemic Sclerosis

Recent Insights into Cellular and Molecular Mechanisms of Defective Angiogenesis in Systemic Sclerosis

In systemic sclerosis (SSc, or scleroderma), defective angiogenesis, clinically manifesting with abnormal capillary architecture and severe capillary reduction, represents a hallmark of early-stage disease, usually preceding the onset of tissue fibrosis, and is caused by several cellular and molecular mechanisms affecting microvascular endothelial cells with different outcomes. Indeed, once damaged, endothelial cells can be dysfunctionally activated, thus becoming unable to undergo angiogenesis and promoting perivascular inflammation. They can also undergo apoptosis, transdifferentiate into profibrotic myofibroblasts, or acquire a senescence-associated secretory phenotype characterized by the release of exosomes and several profibrotic and proinflammatory mediators. In this narrative review, we aimed to give a comprehensive overview of recent studies dealing with the cellular and molecular mechanisms underlying SSc defective angiogenesis and the related endothelial cell dysfunctions, mainly the endothelial-to-mesenchymal transition process. We also discussed potential novel vascular treatment strategies able to restore the angiogenic process and reduce the endothelial-to-mesenchymal transition in this complex disease.

Buyang Huanwu Decoction alleviates blood stasis, platelet activation, and inflammation and regulates the HMGB1/NF-κB pathway in rats with pulmonary fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Qi deficiency and blood stasis are identified to be pathological factors of pulmonary fibrosis (PF) in traditional Chinese medicine (TCM) theory. Buyang Huanwu Decoction (BYHWD) is a traditional Chinese prescription ameliorating Qi deficiency and blood stasis.

AIM OF THE STUDY

The objective of this study was to investigate the anti-fibrosis effect of BYHWD and the potential molecular mechanism in rats.

MATERIALS AND METHODS

Bleomycin was used to construct PF rat models. 27 PF rats were randomly divided into three groups based on treatments: model group (saline solution, n = 9), low-dose BYHWD group (3.5 g/kg, n = 9), and high-dose BYHWD group (14.0 g/kg, n = 9). Moreover, 9 normal rats were used as the blank group. The blood viscosity, coagulation indexes (APTT, TT, PT, and FIB), platelet-related parameters (PLT, PDW, MPV, PCT, and PLCR), platelet microparticles (PMPs), and inflammatory factors (IL-2, IL-10, IL-1β, IL-6, IL-8, IL-17, IFN-γ, TNF-α, PAC-1, HMGB1, NF-κB, and TF) were determined. The lung tissue samples of rats were observed after hematoxylin-eosin (HE) staining. The full component analysis of the BYHWD extract was performed using the ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. The signaling pathway included into the study was selected on the basis of bioinformatics analysis and the results of the phytochemical analysis. The expression levels of genes and proteins involved in the selected signaling pathway were detected.

RESULTS

Compared to the blank group, the whole blood viscosity, PLR, PDW, MPV, PCT, PLCR, PMPs, and the levels of IL-1β, IL-6, IL-8, IL-17, TNF-α, PAC-1, HMGB1, NF-κB, and TF were increased, while the levels of IL-2 and IL-10 were decreased in the model group. Both low-dose BYHWD and high-dose BYHWD reversed these PF-induced effects in spite of the fact that low-dose BYHWD had no significant effect on the level of NF-κB. In addition, BYHWD ameliorated PF-induced inflammation in the rat lung tissue. The phytochemical analysis of the BYHWD extract combined with the bioinformatics analysis suggested that the therapeutical effect of BYHWD on PF was related to the HMGB1/NF-κB pathway, which consisted of NF-κB, IKBKB, ICAM1, VCAM1, HMGB1, and TLR4. Both RT-qPCR and western blot analyses showed that PF induced increases in the expression levels of NF-κB, ICAM1, VCAM1, HMGB1, and TLR4, but a decrease in the expression level of IKBKB. Moreover, both low-dose BYHWD and high-dose BYHWD exerted the opposite effects, and recovered the expression levels of NF-κB, ICAM1, VCAM1, HMGB1, TLR4, and IKBKB, despite the fact that low-dose BYHWD had no effects on the mRNA expression levels of NF-κB or TLR4.

CONCLUSIONS

In summary, BYHWD alleviated PF-induced blood stasis, platelet activation, and inflammation in the rats. Our study suggested BYHWD had a therapeutic effect on PF and was a good alternative for the complementary therapy of PF, and the potential molecular mechanism was modulation of HMGB1/NF-κB signaling pathway, and it needs further study.

Exploring the Utility of Circulating Endothelial Cell-Derived Extracellular Vesicles as Markers of Health and Damage of Vasal Endothelium in Systemic Sclerosis Patients Treated with Iloprost

Endothelial cell-derived extracellular vesicles (eEVs) are released from endothelial cells, signifying endothelial integrity. Systemic Sclerosis (SSc) is a rare disease causing skin and organ fibrosis with early vascular damage. Iloprost, an SSc treatment, might affect eEV release, showing long-term benefits. We aimed to study eEVs in SSc, potentially serving as disease markers and linked to Iloprost's impact on organ involvement. We included 54 SSc patients and 15 healthy donors. Using flow cytometry on platelet-poor plasma (PPP) with specific antibodies (CD144, CD146, AnnexinV), we detected endothelial extracellular vesicles. Results showed fewer eEVs from apoptotic or normal cells in SSc patients than healthy controls. Specifically, patients with diffuse cutaneous SSc and lung issues had reduced eEVs from apoptotic endothelial cells (CD146+ AnnV+). No notable differences were seen in CD144 endothelial markers between patients and controls. After 1-day Iloprost infusion, there was an increase in eEVs, but not after 5 days. These findings suggest circulating eEVs reflect endothelial health/damage, crucial in early SSc stages. A 1-day Iloprost infusion seems effective in repairing endothelial damage, critical in scleroderma vasculopathy. Differences in marker outcomes may relate to CD146's surface expression and CD144's junctional location in endothelial cells.

Role of Extracellular Vesicles in the Propagation of Lung Fibrosis in Systemic Sclerosis

OBJECTIVES

Systemic sclerosis (SSc) has the highest mortality rate among the rheumatic diseases, with lung fibrosis leading as the cause of death. A characteristic of severe SSc-related lung fibrosis is its progressive nature. Although most research has focused on the pathology of the fibrosis, the mechanism mediating the fibrotic spread remains unclear. We hypothesized that extracellular vesicle (EV) communication drives the propagation of SSc lung fibrosis.

METHODS

EVs were isolated from normal (NL) or SSc-derived human lungs and primary lung fibroblasts (pLFs). EVs were also isolated from human fibrotic lungs and pLFs induced experimentally with transforming growth factor-β (TGFβ). Fibrotic potency of EVs was assessed using functional assays in vitro and in vivo. Transmission electron microscopy, nanoparticle tracking analysis, real-time quantitative polymerase chain reaction (RT-qPCR), immunoblotting, and immunofluorescence were used to analyze EVs, their cargo, extracellular matrix (ECM) fractions, and conditioned media.

RESULTS

SSc lungs and pLFs released significantly more EVs than NL lungs, and their EVs showed increased fibrotic content and activity. TGFβ-stimulated NL lung cores and pLFs increased packaging of fibrotic proteins, including fibronectin, collagens, and TGFβ, into released EVs. The EVs induced a fibrotic phenotype in recipient pLFs and in vivo in mouse lungs. Furthermore, EVs interacted with and contributed to the ECM. Finally, suppressing EV release in vivo reduced severity of murine lung fibrosis.

CONCLUSIONS

Our findings highlight EV communication as a novel mechanism for propagation of SSc lung fibrosis. Identifying therapies that reduce EV release, activity, and/or fibrotic cargo in SSc patient lungs may be a viable therapeutic strategy to improve fibrosis.

Circulating extracellular vesicles in the context of interstitial lung disease related to systemic sclerosis: A scoping literature review

BACKGROUND

Interstitial lung disease (ILD) is a significant cause of disability and mortality in systemic sclerosis (SSc), where lung fibrosis stems from the interaction of cells within the epithelial, endothelial, interstitial, and immune cell compartments. Extracellular vesicles (EVs) are particles released by cells capable of transferring functionally active molecules, playing a crucial role in intercellular communication. This scoping review aims to identify and map existing evidence about the role of EVs as biomarkers or pathophysiological actors in SSc-ILD. It also retrospectively assesses the compliance of published articles with the current reporting guidelines established by the International Society of Extracellular Vesicles (ISEV).

METHODS

This scoping review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. The searches were conducted up until 31 May 2023, with no restrictions on the starting year.

RESULTS

Out of 778 publications identified and screened, 9 references were selected. The eligible studies collectively involved a total of 539 SSc patients, with 220 patients presenting with ILD, as demonstrated by high-resolution computed tomography. The studies largely focused on the quantitative assessment of EVs through flow cytometry, primarily concerning larger EVs. The studies primarily focused on the association of EV features with vascular complications, with fibrotic pulmonary involvement typically explored as a secondary finding. The evaluated patients' clinical characteristics were significantly heterogeneous across the studies as well as the association of EV features with the evidence of ILD but none of them longitudinally investigated the relationships with SSc-ILD prognosis. Adherence of these exploratory studies to ISEV reporting guidelines in terms of EV nomenclature, reporting of pre-analytic variables, and qualitative verification of EV separation products was incomplete.

CONCLUSIONS

The evidence concerning the clinical association of EV features is limited and conflicting. The interpretation of available data is substantially biased due to patient selection tailored for vascular complications, heterogeneity of separation methodology, and a lack of validation procedures.

Platelet extracellular vesicles: Darkness and light of autoimmune diseases

Autoimmune diseases are characterized by a breakdown of immune tolerance, leading to inflammation and irreversible end-organ tissue damage. Platelet extracellular vesicles are cellular elements that are important in blood circulation and actively participate in inflammatory and immune responses through intercellular communication and interactions between inflammatory cells, immune cells, and their secreted factors. Therefore, platelet extracellular vesicles are the "accelerator" in the pathological process of autoimmune diseases; however, this robust set of functions of platelet extracellular vesicles has also prompted new advances in therapeutic strategies for autoimmune diseases. In this review, we update fundamental mechanisms based on platelet extracellular vesicles communication function in autoimmune diseases. We also focus on the potential role of platelet extracellular vesicles for the treatment of autoimmune diseases. Some recent studies have found that antiplatelet aggregation drugs, specific biological agents can reduce the release of platelet extracellular vesicles. Platelet extracellular vesicles can also serve as vehicles to deliver drugs to targeted cells. It seems that we can try to silence or inhibit microRNA carried by platelet extracellular vesicles transcription and regulate the target cells to treat autoimmune diseases as platelet extracellular vesicles can transfer microRNA to other cells to regulate immune-inflammatory responses. Hopefully, the information presented here will provide hope for patients with autoimmune diseases.

Platelet-Derived Microparticles and Autoimmune Diseases

Extracellular microparticles provide a means of cell-to-cell communication and can promote information exchanges between adjacent or distant cells. Platelets are cell fragments that are derived from megakaryocytes. Their main functions are to stop bleeding, regulate inflammation, and maintain the integrity of blood vessels. When platelets are activated, they can perform related tasks by secreting platelet-derived microparticles that contain lipids, proteins, nucleic acids, and even organelles. There are differences in the circulating platelet levels in many autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid antibody syndrome, and Sjogren's syndrome. In this paper, the latest findings in the research field of platelet-derived microparticles are reviewed, including the potential pathogenesis of platelet-derived microparticles in various types of immune diseases, their potential as related markers, and for monitoring the progress and prognosis of disease treatment are expounded.

Microparticles: potential new contributors to the pathogenesis of systemic sclerosis?

BACKGROUND

Microparticles (MPs) are membrane-derived vesicles released from cells undergoing activation or apoptosis with diverse proinflammatory and prothrombotic activities, that have been implicated in the pathogenesis of systemic sclerosis (SSc). We aimed to evaluate the plasma levels of platelet-derived microparticles (PMPs), endothelial cell-derived microparticles (EMPs), and monocyte-derived microparticles (MMPs) in SSc patients, and the association between MPs and the clinical features of SSc.

METHODS

In this cross-sectional study, 70 patients with SSc and 35 age- and sex-matched healthy controls were evaluated. Clinical and nailfold capillaroscopy (NFC) data were obtained from all patients. Plasma levels of PMPs (CD42⁺/31⁺), EMPs (CD105⁺), and MMPs (CD14⁺) were quantified by flow cytometry.

RESULTS

Patients were mainly females (90%), with a mean age of 48.9 years old. PMP, EMP, and MMP levels were significantly increased in SSc patients compared to controls (79.2% ± 17.3% vs. 71.0% ± 19.8%, p = 0.033; 43.5% ± 8.7% vs. 37.8% ± 10.4%, p = 0.004; and 3.5% ± 1.3% vs. 1.1% ± 0.5%, p < 0.0001, respectively). PMP levels were significantly higher in patients with positive anti-topoisomerase-I antibodies (p = 0.030) and in patients with a disease duration > 3 years (p = 0.038). EMP levels were lower in patients with a higher modified Rodnan skin score (p = 0.015), and in those with an avascular score > 1.5 in NFC (p = 0.042).

CONCLUSION

The increased levels of PMPs, EMPs and MMPs in scleroderma patients might indicate a possible role for these agents in the pathogenesis of this challenging disease.

Blood TGF-β1 and miRNA-21-5p levels predict renal fibrosis and outcome in IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN), the most common primary glomerulonephritis, often presents as advanced renal failure with end-stage renal disease at diagnosis. Tubulointerstitial injury and fibrosis on histology are the most important predictors of renal outcome. A non-invasive biomarker is required for assessment of progression in IgA nephropathy. We investigated the utility of blood profibrotic molecules, TGF-β1 and miRNA-21-5p (miR-21), to identify a non-invasive biomarker for renal fibrosis in IgAN.

MATERIALS AND METHODS

The study included 30 IgAN (mean age 31.5 ± 9 years) at the time of initial diagnosis, 25 age-sex-matched healthy controls and 10 Lupus nephritis patients as disease controls. Serum TGF-β1 was analyzed by enzyme-linked immunosorbent assay and plasma miR-21 by qRT-PCR, normalized with U6-snRNA. The levels were correlated with clinical features, laboratory parameters, histological Oxford MEST-C score and renal outcome.

RESULTS

The serum TGF-β1 and plasma miR-21 were significantly higher in patients with IgAN than in healthy controls. TGF-β1 significantly correlated with serum creatinine, eGFR, Oxford T score and miR-21. High plasma miR-21 was significantly associated with T score and interstitial inflammation. On multivariate analysis, high levels of TGF-β1 and miR-21 correlated with lower eGFR and T score, respectively. On a follow-up period of 21.5 months, high miR-21 expression at diagnosis was associated (p = 0.02) with a poor renal outcome having a shorter time to doubling of serum creatinine.

CONCLUSION

High blood TGF-β1 and miR-21 expression at diagnosis of IgAN show significant correlation with renal function and degree of chronic tubulointerstitial injury on histology.

The Role of Platelet-Derived Extracellular Vesicles in Immune-Mediated Thrombosis

Platelet-derived extracellular vesicles (PEVs) play important roles in hemostasis and thrombosis. There are three major types of PEVs described based on their size and characteristics, but newer types may continue to emerge owing to the ongoing improvement in the methodologies and terms used to define various types of EVs. As the literature on EVs is growing, there are continuing attempts to standardize protocols for EV isolation and reach consensus in the field. This review provides information on mechanisms of PEV production, characteristics, cellular interaction, and their pathological role, especially in autoimmune and infectious diseases. We also highlight the mechanisms through which PEVs can activate parent cells in a feedback loop.

Microparticles in Autoimmunity: Cause or Consequence of Disease?

Microparticles (MPs) are small (100 nm - 1 um) extracellular vesicles derived from the plasma membrane of dying or activated cells. MPs are important mediators of intercellular communication, transporting proteins, nucleic acids and lipids from the parent cell to other cells. MPs resemble the state of their parent cells and are easily accessible when released into the blood or urine. MPs also play a role in the pathogenesis of different diseases and are considered as potential biomarkers. MP isolation and characterization is technically challenging and results in different studies are contradictory. Therefore, uniform guidelines to isolate and characterize MPs should be developed. Our understanding of MP biology and how MPs play a role in different pathological mechanisms has greatly advanced in recent years. MPs, especially if derived from apoptotic cells, possess strong immunogenic properties due to the presence of modified proteins and nucleic acids. MPs are often found in patients with autoimmune diseases where MPs for example play a role in the break of immunological tolerance and/or induction of inflammatory conditions. In this review, we describe the main techniques to isolate and characterize MPs, define the characteristics of MPs generated during cell death, illustrate different mechanism of intercellular communication via MPs and summarize the role of MPs in pathological mechanisms with a particular focus on autoimmune diseases.

Combined administration of inhaled DNase, baricitinib and tocilizumab as rescue treatment in COVID-19 patients with severe respiratory failure

Aiming to reduce mortality in COVID-19 with severe respiratory failure we administered a combined rescue treatment (COMBI) on top of standard-of-care (SOC: dexamethasone/heparin) consisted of inhaled DNase to dissolve thrombogenic neutrophil extracellular traps, plus agents against cytokine-mediated hyperinflammation, namely anti-IL-6-receptor tocilizumab and JAK1/2 inhibitor baricitinib. Patients with PaO2/FiO2 < 100 mmHg were analysed. COMBI group (n = 22) was compared with similar groups that had received SOC alone (n = 26) or SOC plus monotherapy with either IL-1-receptor antagonist anakinra (n = 19) or tocilizumab (n = 11). COMBI was significantly associated with lower in-hospital mortality and intubation rate, shorter duration of hospitalization, and prolonged overall survival after a median follow-up of 110 days. In vitro, COVID-19 plasma induced tissue factor/thrombin pathway in primary lung fibroblasts. This effect was inhibited by the immunomodulatory agents of COMBI providing a mechanistic explanation for the clinical observations. These results support the conduct of randomized trials using combined immunomodulation in COVID-19 to target multiple interconnected pathways of immunothrombosis.