Enhanced neutrophil apoptosis accompanying myeloperoxidase release during hemodialysis

Neutrophil-to-lymphocyte ratio and prognosis in patients undergoing percutaneous coronary intervention for acute coronary syndrome

OBJECTIVE

The purpose of this study was to characterize Acute Coronary Syndrome (ACS)-associated inflammation by investigating correlates of the neutrophil-to-lymphocyte ratio (NLR), a surrogate marker of inflammation, and its relation to 1-year mortality in a cohort of patients undergoing percutaneous coronary intervention (PCI) for ACS at a single institution.

METHODS

We performed a single-institution, retrospective, observational study of all-comer ACS patients who underwent PCI and were discharged home before the COVID-19 pandemic between September 23, 2011 and July 31, 2017 for who outcomes data were available.

RESULTS

NLRhigh group tended to be older, white patients, less likely to smoke, more likely to have a history of heart failure and cardiac arrest, higher creatinine values, lower LVEF, and higher CK-MB (a surrogate for infarct size). Linear regression model demonstrated a strong correlation between increasing NLR and white race (B = 1.103, p = 0.001, hemoglobin (B = -0.30, p < 0.001), peak CK-MB (B = 0.004, p = 0.02), LVEF (B = -0.048, p < 0.001), and serum creatinine (B = 0.47, p = 0.03). There were a total of 87 deaths at one year. NLR > 3.4 was associated with worse one-year survival post-PCI (91.4 % vs. 95.4 %, log-rank p < 0.004), which was confirmed on multivariate analysis.

CONCLUSION

Our data confirm the independent prognostic significance of inflammation to mortality after ACS and may provide some insight into the putative benefits of inflammation modulation.

The association between C-reactive protein levels and the risk of kidney stones: a population-based study

OBJECTIVES

The relationship between C-reactive protein (CRP) and the risk of developing kidney stones is unclear, and we aimed to assess the association between CRP and kidney stones in US adults.

METHODS

We used data from NHANES 2007-2010, and we excluded participants who were under 18 years of age and lacked data on CRP and kidney stones. Finally, we included a total of 11,033 participants and performed weighted multivariate regression analysis and subgroup analysis to assess the independent relationship between CRP and kidney stones.

RESULTS

The mean prevalence of kidney stones among the participants was 9.8%. Notably, as CRP levels increased, the prevalence of kidney stones exhibited a corresponding rise across quartiles (Kidney stones: Quartile 1: 7.59%; Quartile 2: 8.77%; Quartile 3: 9.64%; Quartile 4: 10.89%). CRP was positively associated with the risk of kidney stones (Model 1: OR = 1.09, 95% CI: 1.01-1.18, p = 0.03; Model 2: OR = 1.09, 95% CI: 1.00-1.18, p = 0.03, Model 3: OR = 1.14, 95%CI: 1.02-1.26, p = 0.04). Participants in the highest CRP quartile experienced a 69% increased risk of kidney stones compared to those in the lowest quartile (OR = 1.64, 95% CI: 1.04-2.59, p = 0.03). Notably, interaction tests revealed that gender, BMI, diabetes, hypertension, CKD and smoking or alcohol consumption status did not significantly influence the association between CRP and kidney stones.

CONCLUSIONS

Our findings reveal a significant association between higher CRP levels and an increased risk of kidney stones. In clinical practice, heightened awareness of CRP as a potential biomarker could aid in risk assessment and management strategies for kidney stone patients.

What is the role of the neutrophil extracellular traps in the cardiovascular disease burden associated with hemodialysis bioincompatibility?

Despite significant progress in dialysis modalities, intermittent renal replacement therapy remains an "unphysiological" treatment that imperfectly corrects uremic disorders and may lead to low-grade chronic inflammation, neutrophil activation, and oxidative stress due to repetitive blood/membrane interactions contributing to the "remaining uremic syndrome" and cardiovascular disease burden of hemodialysis patients. Understanding dialysis bioincompatibility pathways still remains a clinical and biochemical challenge. Indeed, surrogate biomarkers of inflammation including C-reactive protein could not discriminate between all components involved in these complex pathways. A few examples may serve to illustrate the case. Cytokine release during dialysis sessions may be underestimated due to their removal using high-flux dialysis or hemodiafiltration modalities. Complement activation is recognized as a key event of bioincompatibility. However, it appears as an early and transient event with anaphylatoxin level normalization at the end of the dialysis session. Complement activation is generally assumed to trigger leukocyte stimulation leading to proinflammatory mediators' secretion and oxidative burst. In addition to being part of the innate immune response involved in eliminating physically and enzymatically microbes, the formation of Neutrophil Extracellular Traps (NETs), known as NETosis, has been recently identified as a major harmful component in a wide range of pathologies associated with inflammatory processes. NETs result from the neutrophil degranulation induced by reactive oxygen species overproduction via NADPH oxidase and consist of modified chromatin decorated with serine proteases, elastase, bactericidal proteins, and myeloperoxidase (MPO) that produces hypochlorite anion. Currently, NETosis remains poorly investigated as a sensitive and integrated marker of bioincompatibility in dialysis. Only scarce data could be found in the literature. Oxidative burst and NADPH oxidase activation are well-known events in the bioincompatibility phenomenon. NET byproducts such as elastase, MPO, and circulating DNA have been reported to be increased in dialysis patients more specifically during dialysis sessions, and were identified as predictors of poor outcomes. As NETs and MPO could be taken up by endothelium, NETs could be considered as a vascular memory of intermittent bioincompatibility phenomenon. In this working hypothesis article, we summarized the puzzle pieces showing the involvement of NET formation during hemodialysis and postulated that NETosis may act as a disease modifier and may contribute to the comorbid burden associated with dialysis bioincompatibility.

Hemodialysis-Associated Immune Dysregulation in SARS-CoV-2-Infected End-Stage Renal Disease Patients

Patients on hemodialysis show dysregulated immunity, basal hyperinflammation and a marked vulnerability to COVID-19. We evaluated the immune profile in COVID-19 hemodialysis patients and the changes associated with clinical deterioration after the hemodialysis session. Recruited patients included eight hemodialysis subjects with active, PCR-confirmed SARS-CoV-2 infection, five uninfected hemodialysis patients and five healthy controls. In SARS-CoV-2-infected hemodialysis patients TNF-α, IL-6 and IL-8 were particularly increased. Lymphopenia was mostly due to reduction in CD4+ T, B and central memory CD8+ T cells. There was a predominance of classical and intermediate monocytes with reduced HLA-DR expression and enhanced production of pro-inflammatory molecules. Immune parameters were analysed pre- and post-hemodialysis in three patients with COVID-19 symptoms worsening after the hemodialysis session. There was a higher than 2.5-fold increase in GM-CSF, IFN-γ, IL-1β, IL-2, IL-6, IL-17A and IL-21 in serum, and augmentation of monocytes-derived TNF-α, IL-1β and IL-8 and CXCL10 (p < 0.05). In conclusion, COVID-19 in hemodialysis patients associates with alteration of lymphocyte subsets, increasing of pro-inflammatory cytokines and monocyte activation. The observed worsening during the hemodialysis session in some patients was accompanied by augmentation of particular inflammatory cytokines, which might suggest biomarkers and therapeutic targets to prevent or mitigate the hemodialysis-related deterioration during SARS-CoV-2 infection.

Leisure-time regular exercise and prevention of the side effects of immune system activity in middle-aged healthy subjects

Regular exercise is recommended to improve immune system function and antioxidant activity, while conversely, it may cause inflammation by increasing neutrophil-derived main enzyme, myeloperoxidase, which produces reactive oxygen species. The present study aimed to investigate changes in myeloperoxidase level, its influence on total oxidant status, and the capacity of the antioxidant defence system to counteract oxidative stress in middle-aged men participating in leisure-time regular exercise compared to untrained peer subjects. Twenty trained (age 53.58±2.94 years, body mass index (BMI) 25.47±1.6) and 17 untrained (age 54.17±2.83 years, BMI 27.83±1.12) healthy middle-aged men participated in this study [Rasht, Gilan, Iran]. Participants performed a modified Bruce treadmill test as a model of progressive exercise training. Blood samples were taken before, immediately after, and one hour after the end of the test. A mixed ANOVA and Bonferroni post hoc test was used for the analysis of variables. A significant difference was observed in myeloperoxidase levels between groups, while the trained group showed a significantly lower concentration than the untrained group (P<0.018). This result was also consistent with the lower total oxidant status in this group (P<0.001). Total antioxidant capacity changed significantly in both groups with higher concentration in the trained group (P<0.001). The leisure-time regular exercise can reduce myeloperoxidase concentration and total oxidant status in healthy middle-aged men while increasing the total antioxidant capacity, which may potentially protect them from the side effects of immune system activity induced by exercise training.

Vaccination in patients with kidney failure: lessons from COVID-19

Infection is the second leading cause of death in patients with chronic kidney disease (CKD). Adequate humoral (antibody) and cellular (T cell-driven) immunity are required to minimize pathogen entry and promote pathogen clearance to enable infection control. Vaccination can generate cellular and humoral immunity against specific pathogens and is used to prevent many life-threatening infectious diseases. However, vaccination efficacy is diminished in patients with CKD. Premature ageing of the immune system and chronic systemic low-grade inflammation are the main causes of immune alteration in these patients. In the case of SARS-CoV-2 infection, COVID-19 can have considerable detrimental effects in patients with CKD, especially in those with kidney failure. COVID-19 prevention through successful vaccination is therefore paramount in this vulnerable population. Although patients receiving dialysis have seroconversion rates comparable to those of patients with normal kidney function, most kidney transplant recipients could not generate humoral immunity after two doses of the COVID-19 vaccine. Importantly, some patients who were not able to produce antibodies still had a detectable vaccine-specific T cell response, which might be sufficient to prevent severe COVID-19. Correlates of protection against SARS-CoV-2 have not been established for patients with kidney failure, but they are urgently needed to enable personalized vaccination regimens.

Non-Canonical Functions of Myeloperoxidase in Immune Regulation, Tissue Inflammation and Cancer

Myeloperoxidase (MPO) is one of the most abundantly expressed proteins in neutrophils. It serves as a critical component of the antimicrobial defense system, facilitating microbial killing via generation of reactive oxygen species (ROS). Interestingly, emerging evidence indicates that in addition to the well-recognized canonical antimicrobial function of MPO, it can directly or indirectly impact immune cells and tissue responses in homeostatic and disease states. Here, we highlight the emerging non-canonical functions of MPO, including its impact on neutrophil longevity, activation and trafficking in inflammation, its interactions with other immune cells, and how these interactions shape disease outcomes. We further discuss MPO interactions with barrier forming endothelial and epithelial cells, specialized cells of the central nervous system (CNS) and its involvement in cancer progression. Such diverse function and the MPO association with numerous inflammatory disorders make it an attractive target for therapies aimed at resolving inflammation and limiting inflammation-associated tissue damage. However, while considering MPO inhibition as a potential therapy, one must account for the diverse impact of MPO activity on various cellular compartments both in health and disease.

Immune System Dysfunction and Inflammation in Hemodialysis Patients: Two Sides of the Same Coin

Biocompatibility in hemodialysis (HD) has considerably improved in recent decades, but remains an open issue to be solved, appearing essential to reduce systemic inflammation and enhance patients’ clinical outcomes. Clotting prevention, reduction in complement and leukocyte activation, and improvement of antioxidant effect represent the main goals. This review aims to analyze the different pathways involved in HD patients, leading to immune system dysfunction and inflammation. In particular, we mostly review the evidence about thrombogenicity, which probably represents the most important characteristic of bio-incompatibility. Platelet activation is one of the first steps occurring in HD patients, determining several events causing chronic sub-clinical inflammation and immune dysfunction involvement. Moreover, oxidative stress processes, resulting from a loss of balance between pro-oxidant factors and antioxidant mechanisms, have been described, highlighting the link with inflammation. We updated both innate and acquired immune system dysfunctions and their close link with uremic toxins occurring in HD patients, with several consequences leading to increased mortality. The elucidation of the role of immune dysfunction and inflammation in HD patients would enhance not only the understanding of disease physiopathology, but also has the potential to provide new insights into the development of therapeutic strategies.

Inflammation and Cardiovascular Disease Associated With Hemodialysis for End-Stage Renal Disease

Chronic kidney disease (CKD) and cardiac insufficiency often co-exist, particularly in uremic patients on hemodialysis (HD). The occurrence of abnormal renal function in patients with cardiac insufficiency is often indicative of a poor prognosis. It has long been established that in patients with cardiac insufficiency, poorer renal function tends to indicate poorer cardiac mechanics, including left atrial reserve strain, left ventricular longitudinal strain, and right ventricular free wall strain (Unger et al., Eur J Heart Fail, 2016, 18(1), 103–12). Similarly, patients with chronic kidney disease, particularly uremic patients on HD, often have cardiovascular complications in addition to abnormal endothelial function with volume overload, persistent inflammatory states, calcium overload, and imbalances in redox responses. Cardiac insufficiency due to uremia is therefore mainly due to multifaceted non-specific pathological changes rather than pure renal insufficiency. Several studies have shown that the risk of adverse cardiovascular events is greatly increased and persistent in all patients treated with HD, especially in those who have just started HD treatment. Inflammation, as an important intersection between CKD and cardiovascular disease, is involved in the development of cardiovascular complications in patients with CKD and is indicative of prognosis (Chan et al., Eur Heart J, 2021, 42(13), 1244–1253). Therefore, only by understanding the mechanisms underlying the sequential development of inflammation in CKD patients and breaking the vicious circle between inflammation-mediated renal and cardiac insufficiency is it possible to improve the prognosis of patients with end-stage renal disease (ESRD). This review highlights the mechanisms of inflammation and the oxidative stress that co-exists with inflammation in uremic patients on dialysis, as well as the mechanisms of cardiovascular complications in the inflammatory state, and provides clinical recommendations for the anti-inflammatory treatment of cardiovascular complications in such patients.

Risk factors for infection-related hospitalization in end-stage renal disease patients during peri-dialysis period

Infection-related hospitalization during the peri-dialysis period (PDP) in patients with end-stage renal disease (ESRD) has received less attention. Considering the limited data, we explored the risk factors in this population. Retrospective analysis using the data system to examine factors for infection in ESRD during PDP between January 2012 and December 2017. Patients were divided into infected group and non-infected group according to the history of infection. Binary Logistic Regression Model was used to search for risk factors. A total of 478 patients were hospitalized during their PDP. One hundred and ninety patients developed infection (39.75%). Thirty-six patients (18.95%) had two or more infection events, all due to recurrent respiratory infections. The respiratory system was the main site of infection (63.68%), followed by the urinary system and digestive system. Compared with the non-infected group, the infected group had more patients with hypoproteinemia and coronary heart disease. The following factors: C-reactive protein >15 mg/L, procalcitonin >1 ng/L, neutrophil percentage >75%, age >52.5 years, platelet >300 × 10⁹ /L, neutrophil to lymphocyte ratio, and concomitant coronary heart disease were associated with the occurrence of infection in ESRD patients during PDP. Patients with ESRD have a high incidence of infection during the PDP, with respiratory infection most commonly seen. This research identified several factors associated with risk for infection, which should guide the design of infection prevention strategies.

The Pathogenesis of End-Stage Renal Disease from the Standpoint of the Theory of General Pathological Processes of Inflammation

Chronic kidney disease can progress to end-stage chronic renal disease (ESRD), which requires the use of replacement therapy (dialysis or kidney transplant) in life-threatening conditions. In ESRD, irreversible changes in the kidneys are associated with systemic changes of proinflammatory nature and dysfunctions of internal organs, skeletal muscles, and integumentary tissues. The common components of ESRD pathogenesis, regardless of the initial nosology, are (1) local (in the kidneys) and systemic chronic low-grade inflammation (ChLGI) as a risk factor for diabetic kidney disease and its progression to ESRD, (2) inflammation of the classical type characteristic of primary and secondary autoimmune glomerulonephritis and infectious recurrent pyelonephritis, as well as immune reactions in kidney allograft rejection, and (3) chronic systemic inflammation (ChSI), pathogenetically characterized by latent microcirculatory disorders and manifestations of paracoagulation. The development of ChSI is closely associated with programmed hemodialysis in ESRD, as well as with the systemic autoimmune process. Consideration of ESRD pathogenesis from the standpoint of the theory of general pathological processes opens up the scope not only for particular but also for universal approaches to conducting pathogenetic therapies and diagnosing and predicting systemic complications in severe nephropathies.

Amelioration of fatigue in chronic dialysis patients with dialysis solution employing electrolyzed water containing molecular hydrogen (H2) and its association with autonomic function balance

Background

Enhanced oxidative stress is involved with fatigue in hemodialysis (HD) patients. Molecular hydrogen (H2) could improve the redox status. Thus, the study examines whether HD solution rendered by electrolyzed water containing H2 (E-HD) could impact the fatigue and autonomic balance of patients.

Methods

This single-arm, prospective observational study examined 95 patients on chronic HD (54 males; mean age and HD duration; 71.4 years and 10.6 years). Fatigue status on HD and HD-free days was compared between control HD (CHD) and 8 weeks after commencement of E-HD, using a visual analog scale (VAS) and an original scale. Autonomic balance was analyzed with the degree of activities of the sympathetic and parasympathetic nervous system via frequency analysis of a continuous beat interval.

Results

Patients were classified into three groups according to the presence of subjective fatigue during the period of CHD: Group A (40.0%), fatigue only on HD days; Group B (11.6%), presence of fatigue on both HD and HD-free days; and Group C (48.4%), freedom from fatigue. During the 8-week observation period of E-HD, VAS scores were significantly decreased on HD days in Group A, while Group B showed no significant changes in VAS on HD days, but significant decreases on HD-free days. No consistent changes were found in Group C. Significant increases in percentages of patients who reported absence of fatigue were seen in Group A on HD days and in Group B on HD-free days in week 8. Regarding changes in autonomic balance parameters after E-HD commencement, a positive correlation was identified between changes in VAS and autonomic balance in Group A.

Conclusion

E-HD may ameliorate fatigue in patients with subjective symptoms on HD and HD-free days. The influence of autonomic balance by E-HD and its impact on fatigue needs to be elucidated.

Neutrophil-to-Lymphocyte Ratio and Erythropoietin Resistance among Maintenance Hemodialysis Patients

INTRODUCTION

Neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) are recent prognostic biomarkers associated with inflammation. Increased erythropoiesis resistance index (ERI) may predict the risk of all-cause and cardiovascular mortality in hemodialysis (HD) patients. However, the roles of NLR and PLR in erythropoietin (EPO) responsiveness remain unclear in HD patients. This study aims to investigate the relationship between NLR and PLR and EPO responsiveness in maintenance HD patients.

METHODS

A total of 299 HD patients were included in this survey. Laboratory data and demographic details were collected. EPO responsiveness was evaluated by ERI. Pearson correlation analysis and logistic regressions were conducted to evaluate the factors that may be associated with EPO responsiveness.

RESULTS

The EPO responsiveness was positively related to ferritin and negatively related to serum albumin, lymphocytes, and hemoglobin. A multivariate linear regression revealed that only NLR (standardized β = 0.13, p = 0.024) but not PLR (standardized β = 0.107, p = 0.063) was correlated with a higher ERI.

CONCLUSION

A higher NLR level was shown to be a cheaper method to predict worse EPO responsiveness in HD patients.

Amelioration of hemodialysis-induced oxidative stress and fatigue with a hemodialysis system employing electrolyzed water containing molecular hydrogen

Background

A novel hemodialysis (HD) system employing electrolyzed water containing molecular hydrogen (E-HD) has been developed to improve the bio-compatibility of HD. This study examined the impact of E-HD on changes in redox state during HD and HD-related fatigue.

Method

This single-arm, prospective observational study examined 63 patients on chronic HD (41 males; mean age, 72 ± 9 years; median duration of HD, 7 years). Redox parameters (serum myeloperoxidase [MPO], malondialdehyde-protein adduct [MDA-a], thioredoxin 1 [TRX]) during HD were compared between control HD (C-HD) and E-HD after 8 weeks. Fatigue was evaluated using a numerical rating scale (NRS) during the 8-week course.

Results

In C-HD, an increase in serum MPO accompanied increases in both oxidative products (MDA-a) and anti-oxidant molecules (TRX). In E-HD, although increases in MPO were accentuated during HD, changes in MDA-a and TRX were ameliorated as compared with C-HD. In patients who showed HD-related fatigue (47%) during C-HD, change in MDA-a by HD was a risk factor for the presence of fatigue. During the 8 weeks of observation on E-HD, those patients displayed significant decreases in fatigue scores.

Conclusion

E-HD ameliorates oxidative stress and supports anti-oxidation during HD, suggesting improved bio-compatibility of the HD system. E-HD may benefit patients with HD-related fatigue, but the mechanisms underlying changes to oxidative stress have yet to be clarified.

Neutrophils: Many Ways to Die

Neutrophils or polymorphonuclear leukocytes (PMN) are key participants in the innate immune response for their ability to execute different effector functions. These cells express a vast array of membrane receptors that allow them to recognize and eliminate infectious agents effectively and respond appropriately to microenvironmental stimuli that regulate neutrophil functions, such as activation, migration, generation of reactive oxygen species, formation of neutrophil extracellular traps, and mediator secretion, among others. Currently, it has been realized that activated neutrophils can accomplish their effector functions and simultaneously activate mechanisms of cell death in response to different intracellular or extracellular factors. Although several studies have revealed similarities between the mechanisms of cell death of neutrophils and other cell types, neutrophils have distinctive properties, such as a high production of reactive oxygen species (ROS) and nitrogen species (RNS), that are important for their effector function in infections and pathologies such as cancer, autoimmune diseases, and immunodeficiencies, influencing their cell death mechanisms. The present work offers a synthesis of the conditions and molecules implicated in the regulation and activation of the processes of neutrophil death: apoptosis, autophagy, pyroptosis, necroptosis, NETosis, and necrosis. This information allows to understand the duality encountered by PMNs upon activation. The effector functions are carried out to eliminate invading pathogens, but in several instances, these functions involve activation of signaling cascades that culminate in the death of the neutrophil. This process guarantees the correct elimination of pathogenic agents, damaged or senescent cells, and the timely resolution of the inflammation that is essential for the maintenance of homeostasis in the organism. In addition, they alert the organism when the immunological system is being deregulated, promoting the activation of other cells of the immune system, such as B and T lymphocytes, which produce cytokines that potentiate the microbicide functions.