Role of increased neutrophil extracellular trap formation on acute kidney injury in COVID-19 patients

Decreased NETosis-related regulators in neuromyelitis optica spectrum disorders after plasma exchange

OBJECTIVES

To investigate the impact of plasma exchange (PLEX) on NETosis-related regulators and their correlation with neurological improvement in NMOSD patients.

METHODS

Twelve aquaporin-4 antibodies seropositive NMOSD patients were enrolled. NETosis-related regulators (myeloperoxidase [MPO], citrullinated histone H3 [CIT-H3], peptidyl arginine deiminase 4 [PAD4], neutrophil elastase [NE], CD64), pro-inflammatory cytokines (IL-1, IL-6, IL-12, TNF-α) and anti-inflammatory cytokines (IL-10, TGF-β1) were quantitatively assessed before and after PLEX treatment. Clinical assessments included expanded disability status scale (EDSS) and visual outcome scale (VOS) scores.

RESULTS

Following PLEX, all patients showed symptom improvement, with 66.7 % achieving marked-to-moderate improvement (MMI) at 3 months. Key regulators, such as MPO, CIT-H3, PAD4, NE, and pro-inflammatory cytokines such as IL-1, IL-6, IL-12, and TNF-α, exhibited a statistically significant decrease immediately after the initial PLEX session (P < 0.05). Furthermore, CD64 levels demonstrated a substantial decline after the second PLEX session (P < 0.05). Conversely, the levels of anti-inflammatory cytokines, including IL-10 and TGF-β1, displayed an ascending trend post-PLEX. In clinical relevance analysis, among patients who reached MMI, the reductions in MPO, IL-1, and IL-6 exhibited statistically significant differences when compared to patients in the mild-to-no improvement group (P < 0.05). Pearson correlation analysis revealed that the percentage reduction in IL-6 levels after PLEX was positively correlated with the percentage reduction in patient EDSS/VOS scores (r = 0.638, P < 0.05).

CONCLUSIONS

This study highlights that reduced levels of NETosis-related regulators after PLEX contribute to clinical improvement, suggesting the potential involvement of NETosis in the acute neurological impairment observed in NMOSD.

Serum chemokine IL-8 acts as a biomarker for identifying COVID-19-associated persistent severe acute kidney injury

OBJECTIVES

Persistent severe acute kidney injury (PS-AKI) is associated with poor clinical outcomes. Our study attempted to evaluate the diagnostic value of chemokines for early-stage PS-AKI prediction.

METHODS

According to the KDIGO criteria, 115 COVID-19 patients diagnosed with stage 2/3 AKI were recruited from the intensive care unit between December 2022 and February 2023. Primary clinical outcomes included detecting PS-AKI in the first week (≥ KDIGO stage 2 ≥ 72 h). Cytometric Bead Array was used to detect patient plasma levels (interleukin-8 (IL-8), C-C chemokine ligand 5 (CCL5), chemokine (C-X-C Motif) ligand 9 (CXCL9), and interferon-inducible protein 10 (IP-10)) of chemokines within 24 h of enrollment.

RESULTS

Of the 115 COVID-19 patients with stage 2/3 AKI, 27 were diagnosed with PS-AKI. Among the four measured chemokines, only the IL-8 level was significantly elevated in the PS-AKI group than in the Non-PS-AKI group. IL-8 was more effective as a biomarker while predicting PS-AKI with an area under the curve of 0.769 (0.675-0.863). This was superior to other biomarkers related to AKI, including serum creatinine. Moreover, plasma IL-8 levels of >32.2 pg/ml on admission could predict PS-AKI risk (sensitivity = 92.6%, specificity = 51.1%). Additionally, the IL-8 level was associated with total protein and IL-6 levels.

CONCLUSION

Plasma IL-8 is a promising marker for the early identification of PS-AKI among COVID-19 patients. These findings should be validated in further studies with a larger sample size.

Association of corticosteroid therapy with reduced acute kidney injury and lower NET markers in severe COVID-19: an observational study

BACKGROUND

Acute kidney injury (AKI) is common in critical cases of coronavirus disease 2019 (COVID-19) and associated with worse outcome. Dysregulated neutrophil extracellular trap (NET) formation is one of several suggested pathophysiological mechanisms involved in the development of COVID-19 associated AKI. The corticosteroid dexamethasone was implemented as a standard treatment for severe COVID-19 as of June 2020. A sub-analysis of a prospective observational single center study was performed to evaluate the effect of corticosteroid treatment on AKI development and NET markers in critical cases of COVID-19.

RESULTS

Two hundred and ten adult patients admitted to intensive care at a tertiary level hospital due to respiratory failure or shock secondary to SARS-CoV-2-infection between March 13th 2020 and January 14th 2021 were included in the study. Ninety-seven of those did not receive corticosteroids. One hundred and thirteen patients were treated with corticosteroids [dexamethasone (n = 98) or equivalent treatment (n = 15)], but the incidence of AKI was assessed only in patients that received corticosteroids before any registered renal dysfunction (n = 63). Corticosteroids were associated with a lower incidence of AKI (19% vs 55.8%, p < 0.001). Fewer patients demonstrated detectable concentrations of extracellular histones in plasma when treated with corticosteroids (8.7% vs 43.1%; p < 0.001). Extracellular histones and in particular non-proteolyzed histones were observed more frequently with increasing AKI severity (p < 0.001). MPO-DNA was found in lower concentrations in patients that received corticosteroids before established renal dysfunction (p = 0.03) and was found in higher concentrations in patients with AKI stage 3 (p = 0.03). Corticosteroids did not ameliorate established AKI during the first week of treatment.

CONCLUSION

Corticosteroid treatment in severe COVID-19 is associated with a lower incidence of AKI and reduced concentrations of NET markers in plasma.

Zixue Powder attenuates septic thrombosis via reducing neutrophil extracellular trap through blocking platelet STING activation

ETHNOPHARMACOLOGICAL RELEVANCE

Microthrombosis is commonly seen in sepsis and COVID-19. Zixue Powder (ZXP) is a traditional Chinese herbal formula with the potential to treat microvascular and infectious diseases. However, the role and mechanism of ZXP in sepsis-associated thrombosis remain unclear.

AIM OF THE STUDY

Investigating the therapeutic effectiveness and underlying mechanisms of ZXP in septic thrombosis.

MATERIALS AND METHODS

ZXP's compositions were examined with UPLC-QTOF-MS. The efficacy of ZXP on sepsis-induced thrombosis was assessed through various methods: liver tissue pathology was examined using hematoxylin-eosin staining, platelet count was determined by a blood cell analyzer, and an enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of serum tissue factor (TF), thromboxane B2 (TXB2), D-Dimer, and plasminogen activator inhibitor-1 (PAI-1). Neutrophil extracellular traps (NETs) were localized and expressed in liver tissues by immunofluorescence, and the number of NETs in peripheral blood was evaluated by ELISA, which measured the quantity of cf-DNA and MPO-DNA in serum. Platelet P-selectin expression and platelet-neutrophil aggregation were measured by flow cytometry, and plasma P-selectin expression was measured by ELISA. Furthermore, the mechanism of the stimulator of interferon genes (STING) signaling pathway in ZXP's anti-sepsis thrombosis effect was investigated using the STING agonist, Western blot experiments, and immunoprecipitation experiments.

RESULTS

UPLC-QTOF-MS identified 40 chemical compositions of ZXP. Administration of ZXP resulted in significant improvements in liver thrombosis, platelet counts, and levels of TXB2, TF, PAI-1, and D-Dimer in septic rats. Moreover, ZXP inhibited NETs formation in both liver tissue and peripheral blood. Additionally, ZXP decreased the levels of P-selectin in both platelets and plasma, as well as the formation of platelet-neutrophil aggregates, thereby suppressing P-selectin-mediated NETs release. Immunoprecipitation and immunofluorescence staining experiments revealed that ZXP attenuated P-selectin secretion by inhibiting STING-mediated assembly of platelet soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) complex, ultimately preventing inhibition of NETs formation.

CONCLUSION

Our study showed that ZXP effectively mitigates platelet granule secretion primarily through modulation of the STING pathway, consequently impeding NET-associated thrombosis in sepsis. These findings offer valuable insights for future research on the development and application of ZXP.

GPCRs overexpression and impaired fMLP-induced functions in neutrophils from chronic kidney disease patients

Introduction

G-protein coupled receptors (GPCRs) expressed on neutrophils regulate their mobilization from the bone marrow into the blood, their half-live in the circulation, and their pro- and anti-inflammatory activities during inflammation. Chronic kidney disease (CKD) is associated with systemic inflammatory responses, and neutrophilia is a hallmark of CKD onset and progression. Nonetheless, the role of neutrophils in CKD is currently unclear.

Methods

Blood and renal tissue were collected from non-dialysis CKD (grade 3 - 5) patients to evaluate GPCR neutrophil expressions and functions in CKD development.

Results

CKD patients presented a higher blood neutrophil-to-lymphocyte ratio (NLR), which was inversely correlated with the glomerular filtration rate (eGFR). A higher frequency of neutrophils expressing the senescent GPCR receptor (CXCR4) and activation markers (CD18+CD11b+CD62L+) was detected in CKD patients. Moreover, CKD neutrophils expressed higher amounts of GPCR formyl peptide receptors (FPR) 1 and 2, known as neutrophil pro- and anti-inflammatory receptors, respectively. Cytoskeletal organization, migration, and production of reactive oxygen species (ROS) by CKD neutrophils were impaired in response to the FPR1 agonist (fMLP), despite the higher expression of FPR1. In addition, CKD neutrophils presented enhanced intracellular, but reduced membrane expression of the protein Annexin A1 (AnxA1), and an impaired ability to secrete it into the extracellular compartment. Secreted and phosphorylated AnxA1 is a recognized ligand of FPR2, pivotal in anti-inflammatory and efferocytosis effects. CKD renal tissue presented a low number of neutrophils, which were AnxA1+.

Conclusion

Together, these data highlight that CKD neutrophils overexpress GPCRs, which may contribute to an unbalanced aging process in the circulation, migration into inflamed tissues, and efferocytosis.

Association of systemic immune-inflammation index and systemic inflammation response index with chronic kidney disease: observational study of 40,937 adults

BACKGROUND

Chronic kidney disease (CKD) is linked to immunity and inflammation. Systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) are novel measures for gauging an individual's systemic inflammatory activity. We aim to investigate the potential associations between them.

METHODS

This study encompassed a cohort of 40,937 adults from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. SII and SIRI were log2-transformed before conducting regression analysis, considering that these inflammatory markers were right skewed distributed. Weighted logistic regression models assessed the association of log2-SII and log2-SIRI levels with CKD prevalence. Weighted Cox regression models were utilized to estimate the risk of death. Subgroup analyses were performed to further clarify the effects of other covariates on the associations. Sensitivity analyses were performed to assess the robustness of our results.

RESULTS

6986 participants with CKD were recorded, and 2818 patients died during a mean follow-up time of 100 months. After adjusting for all covariates, the highest level of log2-SII increased the CKD incidence (odds ratio [OR]: 1.47, 95% confidence intervals [CI]: 1.32-1.65, P < 0.001), as well as log2-SIRI (OR: 1.79, 95% CI 1.60-2.01, P < 0.001) when compared with the lowest level reference group. The highest level of log2-SII significantly increased all-cause mortality (hazard risk [HR]: 1.29; 95% CI 1.13-1.48, P < 0.001), cardiovascular mortality (HR: 1.61, 95% CI 1.25-2.09, P < 0.001), and hypertension mortality (HR: 1.73, 95% CI 1.23-2.42, P = 0.001) in CKD patients. Additionally, the positive associations were also found between log2-SIRI and all cause (HR: 1.54, 95% CI 1.35-1.76, P < 0.001), cardiovascular (HR: 1.90, 95% CI 1.38-2.60, P < 0.001), and hypertension mortality (HR: 2.15, 95% CI 1.56-2.94, P < 0.001). Subgroup analyses unveiled variations in these effects among different populations.

CONCLUSION

There existed a substantial association of SII and SIRI levels with CKD prevalence, as well as mortality in patients with CKD in the U.S.

POPULATION

Circulating nucleosomes as potential biomarkers for cancer diagnosis and treatment monitoring

Nucleosomes play a crucial role in regulating gene expression through their composition and post-translational modifications. When cells die, intracellular endonucleases are activated and cleave chromatin into oligo- and mono-nucleosomes, which are then released into the body fluids. Studies have shown that the levels of nucleosomes are increased in serum and plasma in various cancer types, suggesting that analysis of circulating nucleosomes can provide an initial assessment of carcinogenesis. However, it should be noted that elevated serum nucleosome levels may not accurately diagnose certain tumor types, as increased cell death may occur in different pathological conditions. Nevertheless, detection of circulating nucleosomes and their histone modifications, along with specific tumor markers, can help diagnose certain types of cancer. Furthermore, monitoring changes in circulating nucleosome levels during chemotherapy or radiotherapy in patients with malignancies can provide valuable insights into clinical outcomes and therapeutic efficacy. The utilization of circulating nucleosomes as biomarkers is an exciting and emerging area of research, with the potential for early detection of various diseases and monitoring of treatment response. Integrating nucleosome-based biomarkers with existing ones may improve the specificity and sensitivity of current assays, offering the possibility of personalized precision medical treatment for patients.