Pro-inflammatory cytokines and leukocyte oxidative burst in chronic kidney disease: culprits or innocent bystanders?

Interferon lambda modulates proinflammatory cytokines production in PBMCs from patients with chronic kidney disease

BACKGROUND

CKD is a major cause of morbidity and mortality worldwide. Considerable evidence now indicates that renal inflammation plays a central role in the initiation and progression of CKD. Recent investigations have demonstrated that IFNλ plays an important role in the pathogenesis of autoimmune and inflammatory diseases. However, the association of IFNλ with CKD is still poorly understood.

OBJECTIVE

To analyze the correlation between IFNλ levels and pro-inflammatory cytokines, and to investigate the effect of IFNλ on PBMCs in patients with CKD.

METHODS

PBMCs were harvested from patients with CKD and healthy controls for measuring the expression level of inflammatory cytokines by RT-qPCR. Spearman correlation test was used to analyze correlation between IFNλ and cytokines as well as eGFR. PBMCs from healthy individuals and CKD patients were subjected to IFNλ protein stimulation. IL6, TNFα, IL10, ISG15 and MX1 mRNA level were measured by RT-PCR, STAT1 and phosphorylated STAT1 protein level were measured by Western blot.

RESULTS

Patients with CKD showed higher levels of IFNλ in PBMCs compared to healthy controls. IFNλ mRNA levels were associated with cytokines and eGFR. The transcription of IL6, TNFα, and IL10 was significantly increased in healthy human PBMCs after IFNλ stimulation. In addition, IFNλ acts on PBMCs by p-STAT1 and ISG15 as well as MX1.

CONCLUSION

High expression of IFNλ was found in CKD patients and was associated with eGFR and disease-related cytokines. More importantly, IFNλ promoted the expression of pro-inflammatory cytokines in PBMCs, suggesting a potential pro-inflammatory role of IFNλ in CKD.

From MIA to FIFA: The vicious matrix of frailty, inflammation, fluid overload and atherosclerosis in peritoneal dialysis

Cardiovascular disease (CVD) is a major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Two decades ago, the common co-existence of malnutrition and systemic inflammation PD patients with atherosclerosis and CVD led to the proposed terminology of 'malnutrition-inflammation-atherosclerosis (MIA) syndrome'. Although the importance of malnutrition is well accepted, frailty represents a more comprehensive assessment of the physical and functional capability of the patient and encompasses the contributions of sarcopenia (a key component of malnutrition), obesity, cardiopulmonary as well as neuropsychiatric impairment. In recent years, it is also increasingly recognized that fluid overload is not only the consequence but also play an important role in the pathogenesis of CVD. Moreover, fluid overload is closely linked with the systemic inflammatory status, presumably by gut oedema, gastrointestinal epithelial barrier dysfunction and leakage of bacterial fragments to the systemic circulation. There are now a wealth of published evidence to show intricate relations between frailty, inflammation, fluid overload and atherosclerotic disease in patients with chronic kidney disease (CKD) and those on PD, a phenomenon that we propose the term 'FIFA complex'. In this system, frailty and atherosclerotic disease may be regarded as two patient-oriented outcomes, while inflammation and fluid overload are two inter-connected pathogenic processes. However, there remain limited data on how the treatment of one component affect the others. It is also important to define how treatment of fluid overload affect the systemic inflammatory status and to develop effective anti-inflammatory strategies that could alleviate atherosclerotic disease and frailty.

The role of neuroimmune and inflammation in pediatric uremia-induced neuropathy

Uremic neuropathy in children encompasses a wide range of central nervous system (CNS), peripheral nervous system (PNS), autonomic nervous system (ANS), and psychological abnormalities, which is associated with progressive renal dysfunction. Clinically, the diagnosis of uremic neuropathy in children is often made retrospectively when symptoms improve after dialysis or transplantation, due to there is no defining signs or laboratory and imaging findings. These neurological disorders consequently result in increased morbidity and mortality among children population, making uremia an urgent public health problem worldwide. In this review, we discuss the epidemiology, potential mechanisms, possible treatments, and the shortcomings of current research of uremic neuropathy in children. Mechanistically, the uremic neuropathy may be caused by retention of uremic solutes, increased oxidative stress, neurotransmitter imbalance, and disturbance of the blood-brain barrier (BBB). Neuroimmune, including the change of inflammatory factors and immune cells, may also play a crucial role in the progression of uremic neuropathy. Different from the invasive treatment of dialysis and kidney transplantation, intervention in neuroimmune and targeted anti-inflammatory therapy may provide a new insight for the treatment of uremia.

Association between estimated GFR and incident hypoglycaemia during hospitalization

BACKGROUND

Kidney function is a significant factor associated with increased incidence of hypoglycaemia, especially among patients with diabetes mellitus (DM). We here quantified the association between elevated creatinine and incident hypoglycaemia among patients admitted to internal medicine departments, with and without DM.

METHODS

This is a retrospective cohort analysis study. Included were all patients discharged from internal medicine units between 2010 and 2013. Patients were excluded if creatinine levels rose or dropped more than 0.3 mg/dL during hospitalization. The CKD-EPI equation was used to calculate glomerular filtration rate (eGFR). Logistic regression analysis (backward LR method) was used to study the association between eGFR and hypoglycaemia incidence.

RESULTS

Included were 39 316 patients (mean age 68.0 ± 18.0 years, 49.3% males, 25.9% with DM, eGFR 69.5 ± 24.9 mL/min/1.73 m² ). Among study participants, 6.5% had at least one hypoglycaemic event. Logistic regression modelling showed that eGFR was inversely associated with incident hypoglycaemia (OR 0.988, 95% CI 0.986-0.990, p < .001). Results were similar for patients with and without DM. Estimated GFR was negatively correlated with admission CRP levels for patients with (r = -.143, p < .001) and without DM (r = -.166, p < .001). Estimated GFR was also positively correlated with admission serum albumin levels for both patients with (r = .304, p < .001) and without DM (r = .354, p < .001).

CONCLUSION

Among non-critically-ill patients hospitalized in internal medicine departments, reduced eGFR is associated with increased risk of hypoglycaemia. Glucose monitoring for all inpatients with CKD is suggested, regardless of DM status.

Hemodialysis raises oxidative stress through carbon-centered radicals despite improved biocompatibility

Leukocyte activation and the resulting oxidative stress induced by bioincompatible materials during hemodialysis impact the prognosis of patients. Despite multiple advances in hemodialysis dialyzers, the prognosis of hemodialysis patients with complications deeply related to oxidative stress, such as diabetes mellitus, remains poor. Thus, we re-evaluated the effects of hemodialysis on multiple reactive oxygen species using electron spin resonance-based methods for further improvement of biocompatibility in hemodialysis. We enrolled 31 patients in a stable condition undergoing hemodialysis using high-flux polysulfone dialyzers. The effects of hemodialysis on reactive oxygen species were evaluated by two methods: MULTIS, which evaluates serum scavenging activities against multiple hydrophilic reactive oxygen species, and i-STrap, which detects lipophilic carbon-center radicals. Similar to previous studies, we found that serum hydroxyl radical scavenging activity significantly improved after hemodialysis. Unlike previous studies, we discovered that scavenging activity against alkoxyl radical was significantly reduced after hemodialysis. Moreover, patients with diabetes mellitus showed a decrease in serum scavenging activity against alkyl peroxyl radicals and an increase in lipophilic carbon-center radicals after hemodialysis. These results suggest that despite extensive improvements in dialyzer membranes, the forms of reactive oxygen species that can be eliminated during dialysis are limited, and multiple reactive oxygen species still remain at increased levels during hemodialysis.

Neutrophil to Lymphocyte Ratio as a Predictor of Long-Term Outcome in Peritoneal Dialysis Patients: A 5-Year Cohort Study

INTRODUCTION

The mortality of peritoneal dialysis (PD) patients remains high. The neutrophil to lymphocyte ratio (NLR), as an indicator of systemic inflammation, has been considered to be a predictor of cardiovascular and all-cause mortality in hemodialysis patients. The present study aims to investigate the relationship between NLR and long-term outcome in PD patients.

MATERIALS AND METHODS

The study included patients who initiated PD for at least 3 months between January 1, 2013, and December 31, 2015. All the patients were followed up until death, cessation of PD, or to the end of the study (June 31, 2018). NLR was calculated as the ratio of neutrophils to lymphocytes.

RESULTS

A total of 140 patients were included in this study. The median NLR reported was 2.87. Patients with lower NLR showed a higher survival rate than patients with higher NLR (log rank 6.886, p = 0.009). Furthermore, patients with higher NLR had a significantly higher cardiovascular mortality (log rank 5.221, p = 0.022). Multivariate Cox proportional hazards model showed that older age (HR 1.054, 95% CI 1.017-1.092, p = 0.004), higher Ca × P (HR 1.689, 95% CI 1.131-2.523, p = 0.010), and higher NLR (HR 2.603, 95% CI 1.037-6.535, p = 0.042) were independent predictors of increased all-cause mortality. NLR was also independently associated with cardiovascular mortality (HR 2.886, 95% CI 1.005-8.283, p = 0.039). Higher NLR (HR 2.667, 95% CI 1.333-5.337, p = 0.006), older age (HR 1.028, 95% CI 1.005-1.052, p = 0.016), and history of cardiovascular disease (HR 1.426, 95% CI 1.195-3.927, p = 0.031) were significantly independently associated with poor peritonitis-free survival in this study.

CONCLUSIONS

NLR could be a strong predictor of long-term outcome in PD patients.

Neutrophil to Lymphocyte Ratio Predicts Adverse Cardiovascular Outcome in Peritoneal Dialysis Patients Younger than 60 Years Old

Background

Neutrophil to lymphocyte ratio (NLR) is a new inflammatory marker; the relationship between NLR and adverse cardiovascular (CV) prognosis has been gradually emphasized in the general population. However, their association in peritoneal dialysis (PD) patients remains unclear.

Methods

From January 1, 2010, to May 31, 2017, a total of 1652 patients were recruited. NLR was categorized in triplicates: NLR ≤ 2.74, 2.74 < NLR ≤ 3.96, and NLR > 3.96. Kaplan-Meier cumulative incidence curve and multivariable COX regression analysis were used to determine the relationship between NLR and the incidence of adverse CV outcome, while a competitive risk model was applied to assess the effects of other outcomes on adverse CV prognosis. Besides, forest plot was investigated to analyze the adverse CV prognosis in different subgroups.

Results

During follow-up, 213 new-onset CV events and 153 CV disease (CVD) deaths were recorded. Multivariable COX regression models showed that the highest tertile of NLR level was associated with increased risk of CV events (HR = 1.39, 95%CI = 1.01‐1.93, P = 0.046) and CVD mortality (HR = 1.81, 95%CI = 1.22‐2.69, P = 0.003), while compared to the lowest tertile. Competitive risk models showed that the differences in CV event (P < 0.001) and CVD mortality (P = 0.004) among different NLR groups were still significant while excluding the effects of other outcomes. In subgroups, with each 1 increased in the NLR level, adjusted HR of new-onset CV event was 2.02 (95%CI = 1.26 − 3.23, P = 0.003) and CVD mortality was 2.98 (95%CI = 1.58 − 5.62, P = 0.001) in the younger group (age < 60 years).

Conclusions

NLR is an independent risk factor for adverse CV prognosis in PD patients younger than 60 years old.

Monocyte/Lymphocyte Ratio and Cardiovascular Disease Mortality in Peritoneal Dialysis Patients

Objectives

The monocyte-to-lymphocyte ratio (MLR), as a new marker of the systemic inflammatory response, is associated with cardiovascular disease (CVD) mortality in the general population and hemodialysis patients. However, the association between the MLR and CVD mortality in peritoneal dialysis (PD) has received little attention.

Methods

In this multicenter retrospective cohort study, 1753 incident PD patients from November 1, 2005, to June 30, 2017, with a baseline MLR were enrolled. The primary endpoint was CVD mortality. The association of MLR with CVD mortality was assessed using a multivariable-adjusted Cox model and the Fine and Gray competing risk model.

Results

Of 1753 patients, the mean age was 51.1 ± 14.9 years, 56.9% of patients were male, and the Charlson comorbidity index was 4.29 ± 1.75. During the follow-up period of 31.2 ± 18.4 months, 368 patients died, of which 200 (54.3%) deaths were caused by CVD events. CVD mortality rates for the lowest, middle, and highest MLR tertiles were 70.6, 78.4, and 88.9 per 1000 patient-years, respectively (P < 0.001). Kaplan-Meier analysis revealed that survival rates were significantly different among the three MLR groups (log rank = 22.41, P < 0.001). Kaplan-Meier analysis revealed that survival rates were significantly different among the three MLR groups (log rank = 22.41, P < 0.001). Kaplan-Meier analysis revealed that survival rates were significantly different among the three MLR groups (log rank = 22.41, P < 0.001). Kaplan-Meier analysis revealed that survival rates were significantly different among the three MLR groups (log rank = 22.41, P < 0.001). After adjusting for confounding factors, the highest MLR tertile was significantly associated with a hazard ratio (HR) for CVD mortality of 1.45 (95% confidence interval, 1.13-2.51, P = 0.016). The Fine and Gray method analysis showed that using all-cause mortality as competing risk, the highest MLR tertile remained an independent predictor of CVD mortality (HR = 1.39, 95% CI 1.10-2.47, P = 0.021).

Conclusions

Higher MLR levels at the commencement of PD may be independently associated with increased CVD mortality in PD patients.

Activatable superparamagnetic iron oxide nanoparticles scavenge reactive oxygen species in macrophages and endothelial cells

Complexed IPC-SPIOs scavenge intracellular ROS after internalization.

Hypoglycemia, Malnutrition and Body Composition

Hypoglycemia is one of the most significant factors to affect prognosis, and is detrimental to patients regardless of diabetes mellitus (DM) status. The classical paradigms dictate that hypoglycemia is a result of overtreatment with glucose lowering agents (iatrogenic hypoglycemia), or, as among patients without DM, this condition is attributed to disease severity. New information shows that hypoglycemia occurs among patients that have a tendency for it. Incident hypoglycemia is very prevalent in the hospital setting, occurring in 1:6 patients with DM and in 1:17 patients without DM (Leibovitz E, Khanimov I, Wainstein J, Boaz M; Diabetes Metab Syndr Clin Res Rev. 13:222-226, 2019).One of the major factors associated with incidence of hypoglycemia is the nutritional status on hospital admission and during the hospitalization. Assessment of nutritional status using questionnaires and biomarkers might be helpful in determining risk of hypoglycemia. Moreover, administration of oral nutritional supplements was shown to decrease this risk.It is also well known that a high burden of comorbidities is associated with an increased risk of hypoglycemia. For example, kidney disease, whether acute or chronic, was shown to increase the risk for hypoglycemia, as well as some endocrine disorders.In this review we elaborate on specific findings that are characteristic of patients at risk for developing hypoglycemia, as well as treatment aimed at preventing its occurrence.

Oxidative Stress in the Pathogenesis and Evolution of Chronic Kidney Disease: Untangling Ariadne's Thread

Amplification of oxidative stress is present since the early stages of chronic kidney disease (CKD), holding a key position in the pathogenesis of renal failure. Induction of renal pro-oxidant enzymes with excess generation of reactive oxygen species (ROS) and accumulation of dityrosine-containing protein products produced during oxidative stress (advanced oxidation protein products—AOPPs) have been directly linked to podocyte damage, proteinuria, and the development of focal segmental glomerulosclerosis (FSGS) as well as tubulointerstitial fibrosis. Vascular oxidative stress is considered to play a critical role in CKD progression, and ROS are potential mediators of the impaired myogenic responses of afferent renal arterioles in CKD and impaired renal autoregulation. Both oxidative stress and inflammation are CKD hallmarks. Oxidative stress promotes inflammation via formation of proinflammatory oxidized lipids or AOPPs, whereas activation of nuclear factor κB transcription factor in the pro-oxidant milieu promotes the expression of proinflammatory cytokines and recruitment of proinflammatory cells. Accumulating evidence implicates oxidative stress in various clinical models of CKD, including diabetic nephropathy, IgA nephropathy, polycystic kidney disease as well as the cardiorenal syndrome. The scope of this review is to tackle the issue of oxidative stress in CKD in a holistic manner so as to provide a future framework for potential interventions.

Contribution of the uremic milieu to an increased pro-inflammatory monocytic phenotype in chronic kidney disease

Intermediate (CD14⁺⁺CD16⁺) monocytes have important pro-inflammatory and atherogenic features and are increased in patients with chronic kidney disease (CKD). The present study aims to elucidate the role of the uremic milieu and of platelet activation in monocyte differentiation. Monocyte subtypes were analyzed in CKD patients (n = 193) and healthy controls (n = 27). Blood from healthy controls (Ctrl; n = 8) and hemodialysis patients (HD; n = 8) was centrifuged, and plasma (pl) was exchanged between Ctrl and HD (Ctrlcells/HDpl and HDcells/Ctrlpl) or reconstituted as original (Ctrlsham and HDsham) and incubated for 24 h (T24). Monocyte differentiation and platelet aggregation to monocytes (MPA) was assessed by flow cytometry. Especially, a higher proportion of CD14⁺⁺CD16⁺ monocytes was found in hemodialysis (HD) patients (p < 0.01). In plasma exchange experiments, Ctrl cells/HD pl T24 showed an increased percentage of CD14⁺⁺CD16⁺ monocytes versus Ctrl sham (33.7% ± 15 vs. 15.7% ± 9.6; P < 0.005), comparable to the level of CD14⁺⁺CD16⁺ monocytes in the HD sham condition. The percentage of CD14⁺⁺CD16⁺ monocytes was lowered by suspending HD cells in Ctrl pl (18.4% ± 7.8 vs. 36.7% ± 15 in HD sham; P < 0.005) reaching the level of the Ctrl sham condition (15.7% ± 9.6). A mixture of uremic sulfates increased CD14⁺⁺CD16⁺ monocytes compared to control (19.8 ± 9.6% vs. 15.8 ± 10.9%; P < 0.05), paralleled by a rise MPA. Blocking MPA by abciximab, a potential therapeutic strategy, or anti-CD62P did not inhibit differentiation towards the CD14⁺⁺CD16⁺ monocytes. In conclusion, in the present cohort, CD14⁺⁺CD16⁺ monocytes are especially increased in HD patients and this can at least in part be attributed to the presence of the uremic milieu, with uremic sulfates inducing a reversible shift towards pro-inflammatory CD14⁺⁺CD16⁺ monocytes.

High Neutrophil-to-Lymphocyte Ratio Predicts Cardiovascular Mortality in Chronic Hemodialysis Patients

The neutrophil-to-lymphocyte ratio (NLR) is a novel simple biomarker of inflammation. It has emerged as a predictor of poor prognosis in cancer and cardiovascular disease in general population. But little was known of its prognostic value in chronic hemodialysis (HD) patients. Here we investigated the association between NLR and cardiovascular risk markers, including increased pulse pressure (PP), left ventricular mass index (LVMI) and intima-media thickness (IMT), and mortality in HD patients. Two hundred and sixty-eight HD patients were enrolled in this study and were followed for 36 months. The primary end point was all-cause mortality and cardiovascular mortality. Multivariable Cox regression was used to calculate the adjusted hazard ratios for NLR on all-cause and cardiovascular survival. We pinpointed that higher NLR in HD patients was a predictor of increased PP, LVMI, and IMT; HD patients with higher NLR had a lower survival at the end of the study; furthermore, high NLR was an independent predictor of all-cause and cardiovascular mortality when adjusted for other risk factors. In conclusion, higher NLR in HD patients was associated with cardiovascular risk factors and mortality.

Sclerostin, TNF-alpha and Interleukin-18 Correlate and are Together with Klotho Related to Other Growth Factors and Cytokines in Haemodialysis Patients

Patients with chronic renal failure are known to have renal osteodystrophy (bone disease) and increased calcification of vessels. A new marker of bone disease, sclerostin, the two pro-inflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin-18 (IL-18), and the fibroblast growth factor-23 (FGF-23) receptor-associated marker Klotho were tested in 84 haemodialysis (HD) patients and in healthy controls. The patients had significantly higher levels of the three former markers than of the controls while Klotho was significantly higher in the controls. Low level, but significant, correlations were observed in the patient group when the levels of these four markers were compared to each other and to those of 5 cytokines and growth factors tested earlier; high-sensitive CRP (hsCRP), interleukin-6 (IL-6), hepatocyte growth factor (HGF), fibroblast growth factor-23 (FGF-23) and soluble urokinase plasminogen activator (suPAR). Ln sclerostin correlated positively to Ln hsTNF-alpha, Ln HGF and Ln suPAR. Ln hsTNF-alpha correlated positively to Ln sclerostin, Ln hsCRP, Ln IL-6, Ln FGF-23, Ln suPAR and Ln IL-18. Ln IL-18 correlated positively to Ln suPAR and Ln TNF-alpha. Ln Klotho correlated negatively to Ln hsCRP but did not correlate to Ln FGF-23. The markers studied here may be involved in the calcification of vessels seen in HD patients due to a combination of inflammation and bone disease. The mechanisms are still not fully known but may be of importance for future therapeutic possibilities in this group of patients.

Uraemic toxins and new methods to control their accumulation: game changers for the concept of dialysis adequacy

The current concept of an adequate dialysis based only on the dialysis process itself is rather limited. We now have considerable knowledge of uraemic toxicity and improved tools for limiting uraemic toxin accumulation. It is time to make use of these. A broader concept of adequacy that focusses on uraemic toxicity is required. As discussed in the present review, adequacy could be achieved by many different methods in combination with, or instead of, dialysis. These include preservation of renal function, dietary intake, reducing uraemic toxin generation rate and intestinal absorption, isolated ultrafiltration and extracorporeal adsorption of key uraemic toxins. A better measure of the quality of dialysis treatment would quantify the uraemic state in the patient using levels of a panel of key uraemic toxins. Treatment would focus on controlling uraemic toxicity while reducing harm or inconvenience to the patient. Delivering more dialysis might not be the best way to achieve this.