Uremia impairs monocyte and monocyte-derived dendritic cell function in hemodialysis patients

Effect of Cellular Senescence in Disease Progression and Transplantation: Immune Cells and Solid Organs

Aging of the world population significantly impacts healthcare globally and specifically, the field of transplantation. Together with end-organ dysfunction and prolonged immunosuppression, age increases the frequency of comorbid chronic diseases in transplant candidates and recipients, contributing to inferior outcomes. Although the frequency of death increases with age, limited use of organs from older deceased donors reflects the concerns about organ durability and inadequate function. Cellular senescence (CS) is a hallmark of aging, which occurs in response to a myriad of cellular stressors, leading to activation of signaling cascades that stably arrest cell cycle progression to prevent tumorigenesis. In aging and chronic conditions, senescent cells accumulate as the immune system's ability to clear them wanes, which is causally implicated in the progression of chronic diseases, immune dysfunction, organ damage, decreased regenerative capacity, and aging itself. The intimate interplay between senescent cells, their proinflammatory secretome, and immune cells results in a positive feedback loop, propagating chronic sterile inflammation and the spread of CS. Hence, senescent cells in organs from older donors trigger the recipient's alloimmune response, resulting in the increased risk of graft loss. Eliminating senescent cells or attenuating their inflammatory phenotype is a novel, potential therapeutic target to improve transplant outcomes and expand utilization of organs from older donors. This review focuses on the current knowledge about the impact of CS on circulating immune cells in the context of organ damage and disease progression, discusses the impact of CS on abdominal solid organs that are commonly transplanted, and reviews emerging therapies that target CS.

Acute and Chronic Kidney Disease Worsen Outcomes in Experimental Sepsis

Key Points

Acute kidney disease (AKD) and CKD are common conditions associated with high rates of incident infection, and poor outcomes once infection have been established. We successfully modeled AKD and CKD in rodents and then administered a cecal slurry solution to create peritonitis and tracked sepsis severity, end organ injury, and inflammatory changes. Our results indicate that AKD mice are more susceptible to infection than CKD mice, developing an aggravated inflammatory response and suggests that this condition predisposes to disparate infection risk.

Background

Infection is a leading cause of morbidity in individuals with acute kidney disease (AKD) and CKD. However, there is significant difficulty in modeling infection into an animal host with preexisting kidney disease. We report a novel method of peritoneal infection induced via cecal slurry (CS) inoculation deployed into mice with experimental aristolochic acid–induced AKD and CKD.

Methods

AKD, CKD, and paired control mice were injected with sham, low, or higher doses of donor–recipient matched CS solution. Animal survival, sepsis severity, and change in GFR were tracked longitudinally throughout the study. Histology for kidney injury, flow cytometry, plasma cytokines, and evidence of indirect organ injury from sepsis were also assessed.

Results

Infected AKD mice experienced significantly heightened sepsis severity, with 100% mortality by 24 hours after high CS doses versus no mortality in control mice. In addition, AKD mice receiving lower CS doses developed dramatically increased proinflammatory cytokines and persistent cytopenias. Infected CKD mice also had worse outcomes than paired CKD controls, although less severe than in AKD mice. Interestingly, animals with AKD had worse outcomes than mice with CKD after any CS dose or time point after inoculation, despite higher baseline kidney function and less uremic sequela.

Conclusions

These data confirm that acute bacterial infection can be modeled in animals with established kidney disease and suggest that the clinical state of kidney disease (AKD versus CKD) may influence host susceptibility to infection more than the degree of kidney failure alone.

Altered transcriptomic immune responses of maintenance hemodialysis patients to the COVID-19 mRNA vaccine

Background

End-stage renal disease (ESRD) patients experience immune compromise characterized by complex alterations of both innate and adaptive immunity, and results in higher susceptibility to infection and lower response to vaccination. This immune compromise, coupled with greater risk of exposure to infectious disease at hemodialysis (HD) centers, underscores the need for examination of the immune response to the COVID-19 mRNA-based vaccines.

Methods

The immune response to the COVID-19 BNT162b2 mRNA vaccine was assessed in 20 HD patients and cohort-matched controls. RNA sequencing of peripheral blood mononuclear cells was performed longitudinally before and after each vaccination dose for a total of six time points per subject. Anti-spike antibody levels were quantified prior to the first vaccination dose (V1D0) and 7 d after the second dose (V2D7) using anti-spike IgG titers and antibody neutralization assays. Anti-spike IgG titers were additionally quantified 6 mo after initial vaccination. Clinical history and lab values in HD patients were obtained to identify predictors of vaccination response.

Results

Transcriptomic analyses demonstrated differing time courses of immune responses, with prolonged myeloid cell activity in HD at 1 wk after the first vaccination dose. HD also demonstrated decreased metabolic activity and decreased antigen presentation compared to controls after the second vaccination dose. Anti-spike IgG titers and neutralizing function were substantially elevated in both controls and HD at V2D7, with a small but significant reduction in titers in HD groups (p<0.05). Anti-spike IgG remained elevated above baseline at 6 mo in both subject groups. Anti-spike IgG titers at V2D7 were highly predictive of 6-month titer levels. Transcriptomic biomarkers after the second vaccination dose and clinical biomarkers including ferritin levels were found to be predictive of antibody development.

Conclusions

Overall, we demonstrate differing time courses of immune responses to the BTN162b2 mRNA COVID-19 vaccination in maintenance HD subjects comparable to healthy controls and identify transcriptomic and clinical predictors of anti-spike IgG titers in HD. Analyzing vaccination as an in vivo perturbation, our results warrant further characterization of the immune dysregulation of ESRD.

Funding

F30HD102093, F30HL151182, T32HL144909, R01HL138628. This research has been funded by the University of Illinois at Chicago Center for Clinical and Translational Science (CCTS) award UL1TR002003.

Diabetes Mellitus and Other Comorbidities: Outcome among Covid-19 Patients in Kerala: A Retrospective Observational Study

Background

Covid-19 was declared by the WHO as a pandemic in 2020; India was also severely affected. Diabetes, a major lifestyle disorder, has seen its prevalence rate rising in developing countries. India is home to the world's second-largest population of diabetes. Several studies have reported greater severity and mortality of Covid-19 in diabetic patients.

Methodology

This was a hospital-based retrospective study done in a rural-based medical college in Kerala State. Data was collected using a semi-structured proforma and analysis was performed using Statistical Package for Social Sciences software version 25. The study was part of the STS research program of the Indian Council of Medical Research (ICMR).

Results

There were 567 patients in the study. Those with pre-existing diabetes had a worse outcome compared to those with newly detected diabetes. The presence of CKD was associated with a poor outcome. Patients admitted to the ICU, and those on assisted ventilation also had a lower survival rate; within the subgroup, those on non-invasive ventilation had a better outcome.

Conclusion

Mortality in Covid-19 is multifactorial. Those with diabetes have a poor outcome. Comorbidities have been reported to confer a high mortality rate in Covid-19 but this was not so in our study (except for CKD). Variability in outcome with respect to comorbidities and better outcomes in those who were non-invasively ventilated calls for more research to establish the relationship between pre-existing conditions and severity of disease. The use of non-invasive ventilation could also provide succor to resource-limited communities.

Immune dysfunction in patients with end stage kidney disease; Immunosenescence - Review

The body's defense against environmental factors is realized by physical barriers and cells of both the innate and adaptive immune systems. Patients with end stage kidney disease (ESKD), especially those treated by hemodialysis, have changes in both the function and the number or percent of different leukocyte subsets. Changes were described at the level of monocytes and lymphocyte subsets, which are associated with immunodeficiencies and pro-inflammatory status correlated with degenerative changes and increased cardiovascular risk. These abnormalities have been compared over the past years with alterations appearing as a result ageing. Also, similitudes regarding immunosenescence observed in ESKD patients, in combination with chronic inflammation, are described as the so-called "inflammaging syndrome".

Calprotectin blockade inhibits long-term vascular pathology following peritoneal dialysis-associated bacterial infection

Bacterial infections and the concurrent inflammation have been associated with increased long-term cardiovascular (CV) risk. In patients receiving peritoneal dialysis (PD), bacterial peritonitis is a common occurrence, and each episode further increases late CV mortality risk. However, the underlying mechanism(s) remains to be elucidated before safe and efficient anti-inflammatory interventions can be developed. Damage-Associated Molecular Patterns (DAMPs) have been shown to contribute to the acute inflammatory response to infections, but a potential role for DAMPs in mediating long-term vascular inflammation and CV risk following infection resolution in PD, has not been investigated. We found that bacterial peritonitis in mice that resolved within 24h led to CV disease-promoting systemic and vascular immune-mediated inflammatory responses that were maintained up to 28 days. These included higher blood proportions of inflammatory leukocytes displaying increased adhesion molecule expression, higher plasma cytokines levels, and increased aortic inflammatory and atherosclerosis-associated gene expression. These effects were also observed in infected nephropathic mice and amplified in mice routinely exposed to PD fluids. A peritonitis episode resulted in elevated plasma levels of the DAMP Calprotectin, both in PD patients and mice, here the increase was maintained up to 28 days. In vitro, the ability of culture supernatants from infected cells to promote key inflammatory and atherosclerosis-associated cellular responses, such as monocyte chemotaxis, and foam cell formation, was Calprotectin-dependent. In vivo, Calprotectin blockade robustly inhibited the short and long-term peripheral and vascular consequences of peritonitis, thereby demonstrating that targeting of the DAMP Calprotectin is a promising therapeutic strategy to reduce the long-lasting vascular inflammatory aftermath of an infection, notably PD-associated peritonitis, ultimately lowering CV risk.

Identification of Immune-Related Genes as Biomarkers for Uremia

Purpose

Uremia, which is characterized by immunodeficiency, is associated with the deterioration of kidney function. Immune-related genes (IRGs) are crucial for uremia progression.

Methods

The co-expression network was constructed to identify key modular genes associated with uremia. IRGs were intersected with differentially expressed genes (DEGs) between uremia and control groups and key modular genes to obtain differentially expressed IRGs (DEIRGs). DEIRGs were subjected to functional enrichment analysis. The protein-protein interaction (PPI) network was constructed. The candidate genes were identified using the cytoHubba tool. The biomarkers were identified using various machine learning algorithms. The diagnostic value of the biomarkers was evaluated using receiver operating characteristic (ROC) analysis. The immune infiltration analysis was implemented. The biological pathways of biomarkers were identified using gene set enrichment analysis and ingenuity pathway analysis. The mRNA expression of biomarkers was validated using blood samples of patients with uremia and healthy subjects with quantitative real-time polymerase chain reaction (qRT-PCR).

Results

In total, four biomarkers (PDCD1, NGF, PDGFRB, and ZAP70) were identified by machine learning methods. ROC analysis demonstrated that the area under the curve values of individual biomarkers were > 0.9, indicating good diagnostic power. The nomogram model of biomarkers exhibited good predictive power. The proportions of six immune cells significantly varied between the uremia and control groups. ZAP70 expression was positively correlated with the proportions of resting natural killer (NK) cells, naïve B cells, and regulatory T cells. Functional enrichment analysis revealed that the biomarkers were mainly associated with translational function and neuroactive ligand-receptor interaction. ZAP70 regulated NK cell signaling. The PDCD1 and NGF expression levels determined using qRT-PCR were consistent with those determined using bioinformatics analysis.

Conclusion

PDCD1, NGF, PDGFRB, and ZAP70 were identified as biomarkers for uremia, providing a theoretical foundation for uremia diagnosis.

COVID and the Kidney: An Update

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has led to a global pandemic that continues to be responsible for ongoing health issues for people worldwide. Immunocompromised individuals such as kidney transplant recipients and dialysis patients have been and continue to be among the most affected, with poorer outcomes after infection, impaired response to COVID-19 vaccines, and protracted infection. The pandemic also has had a significant impact on patients with underlying chronic kidney disease (CKD), with CKD increasing susceptibility to COVID-19, risk of hospital admission, and mortality. COVID-19 also has been shown to lead to acute kidney injury (AKI) through both direct and indirect mechanisms. The incidence of COVID-19 AKI has been decreasing as the pandemic has evolved, but continues to be associated with adverse patient outcomes correlating with the severity of AKI. There is also increasing evidence examining the longer-term effect of COVID-19 on the kidney demonstrating continued decline in kidney function several months after infection. This review summarizes the current evidence examining the impact of COVID-19 on the kidney, covering both the impact on patients with CKD, including patients receiving kidney replacement therapy, in addition to discussing COVID-19 AKI.

Expression of Interferon Regulatory Factor 8 (IRF8) and Its Association with Infections in Dialysis Patients

Patients on dialysis have dysfunctions of innate and adaptive immune system responses. The transcriptional factor IRF8 (interferon regulatory factor 8) is primarily expressed in plasmacytoid cells (pDCs) and myeloid dendritic cells (mDCs), playing a crucial role in the maturation of dendritic cells, monocytes, and macrophages, and contributing to protection against bacterial infections. The current study analyzed the expression patterns of IRF8 and assessed its association with the risk of infections in 79 dialysis patients compared to 44 healthy controls. Different subsets of leukocytes and the intracellular expression of IRF8 were measured using flow cytometry. Compared to the healthy controls, the dialysis patients showed significantly reduced numbers of pDCs and significantly increased numbers of natural killer cells and classical and intermediate monocytes. The dialysis patients exhibited decreased numbers of IRF8-positive dendritic cells (pDC p < 0.001, mDC1 p < 0.001, mDC2 p = 0.005) and increased numbers of IRF8-positive monocytes (p < 0.001). IRF8 expression in pDC, mDC, and classical monocytes was lower in the dialysis patients than in the controls. Dialysis patients who required hospitalization due to infections within one year of follow-up displayed significantly reduced IRF8 expression levels in pDCs compared to patients without such infections (p = 0.04). Our results suggest that reduced IRF8 expression in pDCs is a potential risk factor predisposing dialysis patients to serious infections.

Immune response of heterologous versus homologous prime-boost regimens with adenoviral vectored and mRNA COVID-19 vaccines in immunocompromised patients

Due to rare but major adverse reactions to the AstraZeneca adenoviral ChAdOx1-S-nCoV-19 vaccine (ChAd), German health authorities recommended adults under 60 who received one dose of ChAd, to receive a second dose of the BioNTech mRNA BNT162b2 vaccine (BNT) as a booster. Studies in the general population suggest an enhanced efficacy of the heterologous (ChAd-BNT) compared to the homologous (BNT-BNT) vaccination regimen. However, an analysis of the efficacy in patient populations with a high risk of severe COVID-19 due to acquired immunodeficiency is still missing. We therefore compared both vaccination regimens in healthy controls, patients with gynecological tumors after chemotherapy, patients on dialysis and patients with rheumatic diseases concerning the humoral and cellular immune response. The humoral and cellular immune response differed substantially in healthy controls compared to patients with acquired immunodeficiency. Overall, the most significant differences between the two immunization regimens were found in neutralizing antibodies. These were always higher after a heterologous immunization. Healthy controls responded well to both vaccination regimens. However, the formation of neutralizing antibodies was more pronounced after a heterologous immunization. Dialysis patients, on the other hand, only developed an adequate humoral and particularly cellular immune response after a heterologous immunization. Tumor and rheumatic patients also - to a weaker extent compared to dialysis patients - benefited from a heterologous immunization. In conclusion, the heterologous COVID-19 vaccination regimens (ChAd-BNT) seem to have an advantage over the homologous vaccination regimens, especially in immunocompromised patients such as patients with end-stage kidney disease treated with hemodialysis.

Immune response to the mRNA COVID-19 vaccine in hemodialysis patients: cohort study

Background

End-stage renal disease (ESRD) patients experience immune compromise characterized by complex alterations of both innate and adaptive immunity, and results in higher susceptibility to infection and lower response to vaccination. This immune compromise, coupled with greater risk of exposure to infectious disease at hemodialysis (HD) centers, underscores the need for examination of the immune response to the COVID-19 mRNA-based vaccines.

Methods

A transcriptomic analysis of the immune response to the Covid-19 BNT162b2 mRNA vaccine was assessed in 20 HD patients and cohort-matched controls. RNA sequencing of peripheral blood mononuclear cells (PBMCs) was performed longitudinally before and after each vaccination dose for a total of six time points per subject. Anti-spike antibody levels were quantified prior to the first vaccination dose (V1D0) and seven days after the second dose (V2D7) using anti-Spike IgG titers and antibody neutralization assays. Anti-spike IgG titers were additionally quantified six months after initial vaccination. Clinical history and lab values in HD patients were obtained to identify predictors of vaccination response.

Results

Transcriptomic analyses demonstrated differing time courses of immune responses, with predominant T cell activity in controls one week after the first vaccination dose, compared to predominant myeloid cell activity in HD at this time point. HD demonstrated decreased metabolic activity and decreased antigen presentation compared to controls after the second vaccination dose. Anti-spike IgG titers and neutralizing function were substantially elevated in both controls and HD at V2D7, with a small but significant reduction in titers in HD groups (p < 0.05). Anti-spike IgG remained elevated above baseline at six months in both subject groups. Anti-spike IgG titers at V2D7 were highly predictive of 6-month titer levels. Transcriptomic biomarkers after the second vaccination dose and clinical biomarkers including ferritin levels were found to be predictive of antibody development.

Conclusion

Overall, we demonstrate differing time courses of immune responses to the BTN162b2 mRNA COVID-19 vaccination in maintenance hemodialysis subjects (HD) comparable to healthy controls (HC) and identify transcriptomic and clinical predictors of anti-Spike IgG titers in HD. Analyzing vaccination as an in vivo perturbation, our results warrant further characterization of the immune dysregulation of end stage renal disease (ESRD).

Funding

F30HD102093, F30HL151182, T32HL144909, R01HL138628This research has been funded by the University of Illinois at Chicago Center for Clinical and Translational Science (CCTS) award UL1TR002003.

Impact of monocyte-related modulators and kidney function on mortality in hospitalized patients with COVID-19

Patients with chronic kidney disease (CKD) are at high risk of severe complications from COVID-19 and functional monocyte disturbances have been implicated to play a role. Our objective was to analyse the association between kidney function and monocyte modulatory factors, with risk of mortality in patients with COVID-19. Hospitalized patients with COVID-19 (n = 110) were included and in-hospital mortality was analysed with unadjusted and adjusted multiple logistic regression analysis. Plasma levels of monocyte chemoattractant factors (MIP-1α, MCP-1, IL-6) and a monocyte immune modulator (sCD14) were analysed and correlated to kidney function and risk of mortality. Monocyte modulatory factors were also determined in CKD patients without infection (disease controls) and in healthy subjects. Patients who died in hospital were more often in CKD stages 3-5, with lower estimated glomerular filtration rate (eGFR) and had significantly higher MIP-1α and IL-6 levels than survivors. In multiple regression analyses adjusted for age, sex and eGFR, both high MCP-1 and high MIP-1α were significantly associated with risk of in-hospital mortality. Apart from impaired kidney function, also the concentrations of MCP-1 and MIP-1α add important prognostic information in hospitalized patients with COVID-19. These data provide an increased understanding of the impact of monocyte modulators in patients with COVID-19 and normal or impaired kidney function, and warrant consideration in the pursuit of new effective therapies.

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.

Gastrointestinal parasites in immunocompromised patients; A comparative cross-sectional study

Gastrointestinal parasites (GIPs), including helminths and protozoa species, are a major health problem in many parts of the world. About 3.5 billion people are affected by the parasites worldwide. GIPs are one of the leading causes of death among immunocompromised individuals and can cause serious clinical complications, especially in people with Human Immunodeficiency Virus (HIV)/AIDS, hemodialysis patients, and transplant recipients. This study aimed to compare the prevalence of GIPs among immunocompromised patients and immunocompetent individuals in Lorestan province, West Iran. In the current study, with a sampling of 232 participants (114 hemodialysis, AIDS, and organ transplantation immunocompromised patients and 118 immunocompetent individuals as the control group), demographic characteristics and risk factors for GIPs were collected through a pre-designed questionnaire. Stool samples of patients and the control group were examined for GIPs using different diagnostic methods including direct smear (saline and Lugol's iodine), Ziehl-Neelsen staining, agar-plate culture, and concentration method (formalin ether sedimentation). To evaluate the relative status of the immune system, TCD4⁺ cells were counted in the blood samples of the subjects by flow cytometry. The results were analyzed using SPSS 21 software, Fisher exact, and chi-square statistical tests. Multivariate modeling of the data was performed using logistic regression. The prevalence of GIPs in immunocompromised patients was more than twice that of immunocompetent individuals in the control group (42.06% vs. 17.79%). The most prevalent parasites identified among immunocompromised patients were Cryptosporidium sp. (27.1%), Blastocystis sp. (16.7%), and Entamoeba coli (14.6%) respectively. Cryptosporidium sp. had the highest frequency among hemodialysis patients (6.49%), AIDS patients (26.92%), and transplant recipients (18.18%) respectively. Patients with AIDS had the highest positive results for Cryptosporidium sp. followed by Microsporidia sp. (23.7%). In immunocompetent individuals, the highest prevalence of GIPs was related to Blastocystis sp and Trichomonas hominis (28.57%). Statistical analysis of the data showed that there was a statistically significant difference between various age groups regarding infection with GIPs so the highest rate of GIPs infection was observed in the age group lower than 50 years (P = 0.035). The statistical difference between the variable of location and infection with GIPs was insignificant but remarkable (P = 0.070). According to the results, it can be concluded that GIP is more common in immunocompromised patients than in immunocompetent individuals with cryptosporidium sp. predominance. Due to the favorable conditions of immunocompromised patients for GIPs and considering them as one of the important sources of parasitic infections and parasite transmission in society, control, prevention, and monitoring of their social behaviors along with health issues are inevitable.

The incidence of cancer recurrence and new cancer following commencement of dialysis in patients with prior cancers

Background

Patients with kidney failure have a higher cancer risk compared with the age-matched general population. However, the outcomes of incident dialysis patients with a prior cancer history are unknown.

Methods

Using Australia and New Zealand Dialysis and Transplant Registry data (2000–2019), the outcomes and survival probabilities of incident dialysis patients with prior cancers and having experienced a cancer recurrence or having developed a new cancer after dialysis commencement were described.

Results

Of 4912 patients with prior cancers before dialysis commencement, 323 (7%) and 343 (7%) patients experienced cancer recurrence or developed new cancers after dialysis initiation, respectively. The median time from dialysis commencement to cancer recurrence was 1.2 years [interquartile range (IQR) 0.5–2.8] and was 2.0 years (IQR 0.7–4.0) for new cancer occurrence. Of those with cancer recurrence, 80% presented with metastatic disease and one in two patients died from cancer, with a median time from cancer recurrence to death of 0.5 years (IQR 0.2–1.7). Of those who developed new cancer, urinary tract and respiratory cancers were the most frequent cancer types, with a median time from new cancer diagnosis to death of 1.3 years (IQR 0.4–3.1). The 3-year survival probabilities on dialysis following cancer recurrence and new cancer were 19% [95% confidence interval (CI) 15–24] and 41% (35–47), respectively.

Conclusion

Among incident dialysis patients with a prior cancer history, 14% experienced cancer recurrence or developed a new cancer. Patients who experienced cancer recurrence or developed new cancer have poor outcomes, with ˂50% surviving beyond 3 years. These findings suggest the need to have a greater understanding of the characteristics, cancer screening, treatment responses and reasons for commencing dialysis in patients with kidney failure and prior cancer history, which may help in the shared clinical decision-making process when considering dialysis for these patients.

Myeloid leukocytes' diverse effects on cardiovascular and systemic inflammation in chronic kidney disease

Chronic kidney disease's prevalence rises globally. Whereas dialysis treatment replaces the kidney's filtering function and prolongs life, dreaded consequences in remote organs develop inevitably over time. Even milder reductions in kidney function not requiring replacement therapy associate with bacterial infections, cardiovascular and heart valve disease, which markedly limit prognosis in these patients. The array of complications is diverse and engages a wide gamut of cellular and molecular mechanisms. The innate immune system is profoundly and systemically altered in chronic kidney disease and, as a unifying element, partakes in many of the disease's complications. As such, a derailed immune system fuels cardiovascular disease progression but also elevates the propensity for serious bacterial infections. Recent data further point towards a role in developing calcific aortic valve stenosis. Here, we delineate the current state of knowledge on how chronic kidney disease affects innate immunity in cardiovascular organs and on a systemic level. We review the role of circulating myeloid cells, monocytes and neutrophils, resident macrophages, dendritic cells, ligands, and cellular pathways that are activated or suppressed when renal function is chronically impaired. Finally, we discuss myeloid cells' varying responses to uremia from a systems immunology perspective.

Sepsis in end-stage renal disease patients: are they at an increased risk of mortality?

OBJECTIVES

This study aims to examine the outcome of end-stage renal disease (ESRD) patients admitted with sepsis to the intensive care unit (ICU).

DESIGN

Single centre, retrospective cohort study.

SETTING

The study was conducted in the Intensive Care Department of King Abdulaziz Medical City, Riyadh, Saudi Arabia.

PARTICIPANTS

Data were extracted from a prospectively collected ICU database from 2002 to 2017. Patients were considered to have sepsis based on the sepsis-3 definition and were stratified into 2 groups based on the presence or absence of ESRD.

PRIMARY AND SECONDARY OUTCOMES

The primary outcome of the study was in-hospital mortality. Secondary outcomes included ICU mortality, ICU and hospital lengths of stay, and mechanical ventilation duration.

RESULTS

A total of 8803 patients were admitted to the ICU with sepsis during the study period. 730 (8.3%) patients had ESRD. 49.04% of ESRD patients with sepsis died within their hospital stay vs. 31.78% of non-ESRD patients. ESRD septic patients had 1.44 greater odds of dying within their hospital stay as compared to septic non-ESRD patients (OR 1.44, 95% CI 1.03-1.53). Finally, the predictors of hospital mortality in septic ESRD patients were found to be mechanical ventilation (OR 3.36; 95% CI 2.27-5.00), a history of chronic liver disease (OR 2.26; 95% CI 1.26-4.07), and use of vasopressors (OR 1.74; 95% CI 1.19-2.54). Among patients with ESRD, hospital mortality was higher in subgroups of patients with chronic cardiac (OR 1.86 (1.36-2.53) vs. 1.19 (0.96-1.47)) and chronic respiratory illnesses (OR 2.20 (1.52-3.20) vs. 1.21 (0.99-1.48)).

CONCLUSION

ESRD patients admitted to the intensive care unit with sepsis are at greater odds of mortality compared to patients with non-ESRD. This risk is particularly increased if these patients have a concomitant history of chronic cardiac and respiratory illnesses.Key MessagesSepsis and bacterial infections are very common in ESRD patients and following cardiovascular disease; sepsis is the second leading cause of death in patients with ESRD.This study aims to examine the outcome of patients with end-stage renal disease (ESRD) patients admitted with sepsis to the intensive care unit (ICU).The results of this study have shown that end-stage renal disease is associated with greater odds of ICU and hospital mortality among septic patients admitted to an intensive care unit.ESRD patients were also more likely to be started on vasopressors and mechanical ventilation.

Longitudinal urinary biomarkers of immunological activation in covid-19 patients without clinically apparent kidney disease versus acute and chronic failure

Kidney function is affected in COVID-19, while kidney itself modulates the immune response. Here, hypothesize if COVID-19 urine biomarkers level can assess immune activation vs. clinical trajectory. Considering the kidney's critical role in modulating the immune response, we sought to analyze activation markers in patients with pre-existing dysfunction. This was a cross-sectional study of 68 patients. Blood and urine were collected within 48 h of hospital admission (H1), followed by 96 h (H2), seven days (H3), and up to 25 days (H4) from admission. Serum level ferritin, procalcitonin, IL-6 assessed immune activation overall, while the response to viral burden was gauged with serum level of spike protein and αspike IgM and IgG. 39 markers correlated highly between urine and blood. Age and race, and to a lesser extend gender, differentiated several urine markers. The burden of pre-existing conditions correlated with urine DCN, CAIX and PTN, but inversely with IL-5 or MCP-4. Higher urinary IL-12 and lower CAIX, CCL23, IL-15, IL-18, MCP-1, MCP-3, MUC-16, PD-L1, TNFRS12A, and TNFRS21 signified non-survivors. APACHE correlated with urine TNFRS12, PGF, CAIX, DCN, CXCL6, and EGF. Admission urine LAG-3 and IL-2 predicted death. Pre-existing kidney disease had a unique pattern of urinary inflammatory markers. Acute kidney injury was associated, and to a certain degree, predicted by IFNg, TWEAK, MMP7, and MUC-16. Remdesavir had a more profound effect on the urine biomarkers than steroids. Urinary biomarkers correlated with clinical status, kidney function, markers of the immune system activation, and probability of demise in COVID-19.

Posterior Reversible Encephalopathy Syndrome: Tips for Diagnosis and Treatment

Often described as a clinico-radiological entity, posterior reversible encephalopathy syndrome (PRES) is being increasingly diagnosed nowadays. However, mystery still surrounds its exact etiology. Though there are no standardized diagnostic criteria for this syndrome, there is a consistent feature associated with it: brain vasogenic edema in combination with neurotoxicity. The nonspecific nature of this condition leaves room for the diagnosis to be overlooked, leading to delays in providing appropriate treatment and unfavorable patient outcomes. PRES is associated with a variety of medical conditions including hypertension, eclampsia, autoimmune conditions, renal failure, sepsis, and an immunocompromised state, such as that secondary to the use of immunosuppressive therapy, human immunodeficiency virus (HIV), and organ transplants. Treatment by a multidisciplinary team and prompt identification and reversal of the underlying cause can lead to beneficial outcomes, as in the case we present in this report.

Current status of COVID-19 among hemodialysis patients in the East Azerbaijan Province of Iran

INTRODUCTION

Management of vulnerable patients during the COVID-19 pandemic requires careful precautions. Hemodialysis patients constitute a large group of at-risk patients that not only suffer from a compromised immune system but also are at a higher risk due to frequent admission to healthcare units. Therefore, a better understanding on the pathogenesis and possible risk factors of COVID-19 in hemodialysis patients is of high importance.

METHODS

A total of 670 maintained hemodialysis patients from all dialysis units of the East Azerbaijan Province of Iran, including 44 COVID-19 patients were included in the present study. Possible associations between the backgrounds of patients and the incidence of COVID-19 were assessed. Also, hemodialysis patients with COVID-19 were compared to 211 nonhemodialysis COVID-19 patients.

FINDINGS

Chronic glomerulonephritis patients and those with blood group A demonstrated a higher incidence of COVID-19. On the other hand, patients with blood group AB⁺ and those with hypertension etiology of kidney failure demonstrated a lower incidence of COVID-19. Hemodialysis patients with COVID-19 had higher counts of polymorphonuclears (PMNs) in their peripheral blood compared to other COVID-19 patients.

DISCUSSION

A better comprehension on the risk factors associated with COVID-19 in hemodialysis patients can improve our understanding on the pathogenesis of COVID-19 in different situations and help the enhancement of current therapeutics for COVID-19 in hemodialysis patients.

Characteris Tics and Causes of Immune Dysfunction Related to Uremia and Dialysis

From the immunologic viewpoint, chronic kidney disease (CKD) is characterized by disorders of both the innate and adaptive systems, generating a complex and still not fully understood immune dysfunction. Markers of a chronically activated immune system are closely linked to several complications of CKD and represent powerful predictors for mortality in the CKD population. On the other hand, CKD patients respond poorly to vaccination and to challenges such as bacterial infection. Interestingly, the main causes of death in patients with CKD are cardiovascular and infectious diseases, both being pathologic processes closely linked to immune function. Therefore, accelerated tissue degeneration (as a consequence of chronic inflammation) and increased rate of sepsis (because of a poorly orchestrated immune response) represent the most important targets for interventions aiming to reduce mortality in CKD patients. Understanding the mechanisms behind the immune dysfunction that is peculiar to CKD generates a perspective to improve outcomes in this group of patients.

Senescence and the Aging Immune System as Major Drivers of Chronic Kidney Disease

Chronic kidney disease (CKD) presents an ever-growing disease burden for the world’s aging population. It is characterized by numerous changes to the kidney, including a decrease in renal mass, renal fibrosis, and a diminished glomerular filtration rate. The premature aging phenotype observed in CKD is associated with cellular senescence, particularly of renal tubular epithelial cells (TECs), which contributes to chronic inflammation through the production of a proinflammatory senescence associated secretory phenotype (SASP). When coupled with changes in immune system composition and progressive immune dysfunction, the accumulation of senescent kidney cells acts as a driver for the progression of CKD. The targeting of senescent cells may well present an attractive therapeutic avenue for the treatment of CKD. We propose that the targeting of senescent cells either by direct inhibition of pro-survival pathways (senolytics) or through the inhibition of their proinflammatory secretory profile (senomorphics) together with immunomodulation to enhance immune system surveillance of senescent cells could be of benefit to patients with CKD.

Monocytes in Uremia

Monocytes play an important role in both innate immunity and antigen presentation for specific cellular immune defense. In patients with chronic renal failure, as well as those treated with maintenance hemodialysis, these cells are largely dysregulated. There is a large body of literature on monocyte alterations in such patients. However, most of the publications report on small series, there is a vast spectrum of different methods and the heterogeneity of the data prevents any meta-analytic approach. Thus, a narrative review was performed to describe the current knowledge. Monocytes from patients with chronic renal failure differ from those of healthy individuals in the pattern of surface molecule expression, cytokine and mediator production, and function. If these findings can be summarized at all, they might be subsumed as showing chronic inflammation in resting cells together with limited activation upon immunologic challenge. The picture is complicated by the fact that monocytes fall into morphologically and functionally different populations and population shifts interact heavily with dysregulation of the individual cells. Severe complications of chronic renal failure such as impaired immune defense, inflammation, and atherosclerosis can be related to several aspects of monocyte dysfunction. Therefore, this review aims to provide an overview about the impairment and activation of monocytes by uremia and the resulting clinical consequences for renal failure patients.

Chronic Kidney Disease-Associated Immune Dysfunctions: Impact of Protein-Bound Uremic Retention Solutes on Immune Cells

Regardless of the primary disease responsible for kidney failure, patients suffering from chronic kidney disease (CKD) have in common multiple impairments of both the innate and adaptive immune systems, the pathophysiology of which has long remained enigmatic. CKD-associated immune dysfunction includes chronic low-grade activation of monocytes and neutrophils, which induces endothelial damage and increases cardiovascular risk. Although innate immune effectors are activated during CKD, their anti-bacterial capacity is impaired, leading to increased susceptibility to extracellular bacterial infections. Finally, CKD patients are also characterized by profound alterations of cellular and humoral adaptive immune responses, which account for an increased risk for malignancies and viral infections. This review summarizes the recent emerging data that link the pathophysiology of CKD-associated immune dysfunctions with the accumulation of microbiota-derived metabolites, including indoxyl sulfate and p-cresyl sulfate, the two best characterized protein-bound uremic retention solutes.

The relationship between neutrophil-to-lymphocyte ratio and the first occurrence of pneumonia in peritoneal dialysis patients

BACKGROUND

Although neutrophil-to-lymphocyte ratio (NLR) is closely associated with pneumonia in the general population, its relationship is unclear in peritoneal dialysis (PD) patients.

METHODS

This is a cohort study consisting of 739 PD patients and dividing into two groups. Kaplan-Meier curves were applied to observe the incidence of the first occurrence of pneumonia, competitive risk analysis was conducted to compare whether there was a significant difference in each NLR group in the presence of other competing events, multivariable COX regression analysis was used to evaluate the hazard ratios (HRs), as well as forest plot was used to analyze the relationship between NLR and the first occurrence of pneumonia in different subgroups.

RESULTS

Of all the patients, 116 cases of first-time pneumonia were recorded. The first-time pneumonia incidence rate was 71.67/1000 patient-years in high NLR group, which was markedly higher than that of 45.81/1000 patient-years in low NLR group. Kaplan-Meier curves indicated significant differences in the incidence of the first occurrence of pneumonia between two groups (log-rank test p = 0.015). The competitive risk model suggested a significant difference in the cumulative incidence of first pneumonia between the two groups (p = 0.032). Compared to low NLR group, adjusted Cox model showed that high NLR group was associated with increased risk of pneumonia incidence (HR, 1.51; 95% CI 1.04-2.21; p = 0.031). Forest plot showed no interaction was found in subgroups.

CONCLUSIONS

The risk of pneumonia was significantly increasing in PD patients with high NLR, which may have a certain guiding significance for the clinic.

Beta-glucans in advanced CKD: role in endotoxaemia and inflammation

Background/aims

(1–3)-β-D glucans (BG) are cellular components of yeasts and fungi. Elevated blood levels may be an adjunct in diagnosing invasive fungal infection, though can be high in dialysis patients without fungaemia. BG can also induce false positive signals in endotoxin detection assays (Limulus Amoebocyte Lysate [LAL] assay). We explored the relationship between BG levels, renal impairment, endotoxaemia and inflammation.

Methods

We measured serum BG levels, markers of inflammation and blood endotoxin levels in 20 controls, 20 with stages 1–3 chronic kidney disease (CKD), 20 with stages 4–5 CKD, 15 on peritoneal dialysis (PD) and 60 on haemodialysis (HD). Another 30 patients were studied before and after HD initiation.

Results

BG levels increased with advancing CKD, being highest in HD patients, 22% of whom had elevated levels (> 80 pg/ml). Levels increased significantly following HD initiation. Levels also correlated positively with CRP, TNFα, IL-6 levels, independently of CKD stage. Blood endotoxin was detectable by LAL assays in 10–53% of the CKD cohort, being most prevalent in the HD group, and correlating positively with BG levels. Adding BG blocking agent to the assay reduced endotoxin detection confining it to only 5% of HD patients. Levels of inflammatory markers were higher in those with detectable endotoxin - whether false- or true positives.

Conclusion

BG levels increased with decreasing renal function, being highest in dialysis patients. High BG levels were associated with false positive blood endotoxin signals, and with markers of inflammation, independently of CKD stage. The cause for high BG levels is unknown but could reflect increased gut permeability and altered mononuclear phagocytic system function.

Immune response to influenza vaccination in ESRD patients undergoing hemodialysis vs. hemodiafiltration

BACKGROUND

On-line hemodiafiltration (HDF) clears more azotemic toxins compared to high-flux hemodialysis (HD). The response to vaccination is impaired in dialysis patients. We wished to determine whether the immune responses to influenza vaccine in dialysis patients treated by HDF were stronger than those treated by HD.

MATERIALS AND METHODS

We conducted a prospective cohort study in chronic dialysis patients during the 2016 and 2017 influenza seasons. All participants received a single standard dose of trivalent influenza vaccine, and we studied the elicited humoral immune response by hemagglutination inhibition test, and cell-mediated immune response by enumeration of lymphocyte cellular markers and proliferation assays.

RESULTS

We immunized 60 end-stage renal disease (ESRD) patients: 42 (70%) treated with HD and 18 patients (30%) with HDF. The median (interquartile range) age was 65.0 (55.0-74.5) years. All patients developed seroprotection to at least one influenza vaccine strain at one month post-vaccination, and did not differ between groups. By logistic regression, age was the only factor independently associated with seroconversion to all vaccine strains (odds ratio 0.89, 95% confidence interval 0.80-0.98; p = 0.022). Seroprotection to all vaccine strains was sustained for longer in patients treated with HDF, and the results remained the same after age adjustment. For cellular immune response, patients who seroconverted to all vaccine strains had higher CD38+ T cell subpopulations pre-vaccination. Patients treated by HDF had higher lymphocyte proliferation to circulating influenza A strains.

CONCLUSIONS

Seroconversion to all influenza vaccine strains was associated with age. Patients treated with HDF demonstrated seroprotection was sustained for longer compared to those treated by HD and greater lymphocyte proliferation to circulating influenza A strains. These encouraging results for HDF require confirmation in a larger dialysis population.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT04122222.

Impaired production of immune mediators in dengue virus type 2-infected mononuclear cells of adults with end stage renal disease

Chronic kidney disease is an epidemiologically identified risk factor for development of severe dengue in dengue-affected patients. However, available data on the immune pathogenesis in end stage renal disease (ESRD) patients affected by dengue is insufficient. We performed an in vitro study to evaluate the sequential immunological reactions and viral load in dengue virus type 2-infected mononuclear cells of patients with ESRD (n = 34) and in healthy controls (n = 30). The concentrations of interleukins (IL)-1 receptor antagonist (Ra), IL-2, IL-6, IL-8, IL-10, IL-12p40, granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1b (MIP-1b), vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-α and viral load cycle threshold (Ct) were measured in the dengue virus type 2-infected mononuclear cells at 6 h, 24 h, 48 h, and 72 h post-infection. We found in the ESRD group significantly higher GM-CSF and IL-2 levels at 6 h post-infection. However, IL-8, IL-10, IL-12p40, TNF-α, MCP-1, and MIP-1b levels were found significantly lower than in the control group. At 24 h, 48 h, and 72 h post-infection, significantly lower levels of IL-1Ra, IL-6, IL-8, IL-10, IL-12p40, TNF-α, MCP-1, and MIP-1b were detected in ESRD group. Concentration of VEGF at 24 h and 48 h, and of GM-CSF at 48 h and 72 h were also found to be lower in ESRD group than in control group. Compared with controls, the viral load Ct values were significantly lower in ESRD group at 6 h and 24 h post-infection No significant difference in viral load Ct values between two groups was found at 48 h and 72 h post-infection. Our study discloses that the expression of immune mediators of dengue-infected mononuclear cells is impaired in ESRD patients.

Klotho restrain RIG-1/NF-κB signaling activation and monocyte inflammatory factor release under uremic condition

AIMS

Systemic inflammation is a main hallmark of chronic kidney disease (CKD), but the underlying mechanisms of pathogenesis of CKD-associated systemic inflammation is unclear. Current study was designed to investigate the relationship between indoxyl sulphate (IS) and CKD-associated systemic inflammation along with the protective effects of Klotho in CKD.

METHODS

IS serum levels from patients were detected by high-performance liquid chromatography (HPLC), and Serum Klotho, IL-6 and TNF-α were measured separately by ELISA and Real-Time PCR analysis. Monocytes were incubated with or without Klotho, while the expressions of retinoic acid-inducible gene I (RIG-I) and NF-κB were analyzed through Western blot assay. Heterozygous kl/kl (kl/+) mice or WT mice were treated with 5/6 renal damage. Thereafter, the CKD mice were intraperitoneally injected with recombinant Klotho protein or PBS.

KEY FINDINGS

It shows that in 286 CKD patients, the serum levels of inflammatory factors were positively related with IS, but negatively related with Klotho. Klotho significantly inhibited IS-induced RIG-I/NF-κB activation and productions of both IL-6 and TNF-α in cultured monocytes. In vivo, along with the increase of IS and decrease of Klotho in the serum, the activation of RIG-I/NF-κB signaling was observed in peripheral blood monocytes in both CKD mice and patients. Notably, higher levels of IL-6 and TNF-α were detected in kl+/- mice given CKD. Klotho administration has evidently attenuated RIG-I/NF-κB activation in monocytes and systemic inflammation in CKD mice.

SIGNIFICANCE

The findings suggest that Klotho can suppress CKD-associated systemic inflammation through inhibiting IS-induced RIG-1/NF-κB activation and monocyte inflammatory factor release.

Infectious Disease Risk in Dialysis Patients: A Transdisciplinary Approach

Purpose of review:

Infections are a major contributor to morbidity and mortality in end-stage renal disease (ESRD) patients. A better understanding of the interplay between infectious processes and ESRD may eventually lead to the development of targeted treatment strategies aimed at lowering overall disease morbidity and mortality. Monogenic causes are a major contributor to the development of adult chronic kidney disease (CKD). Recent studies identified a genetic cause in 10% to 20% of adults with CKD. With the introduction of whole-exome sequencing (WES) into clinical mainstay, this proportion is expected to increase in the future. Once patients develop CKD/ESRD due to a genetic cause, secondary changes, such as a compromised immune status, affect overall disease progression and clinical outcomes. Stratification according to genotype may enable us to study its effects on secondary disease outcomes, such as infectious risk. Moreover, this knowledge will enable us to better understand the molecular interplay between primary disease and secondary disease outcomes.

Sources of information:

We conducted a literature review using search engines such as PubMed, PubMed central, and Medline, as well as cumulative knowledge from our respective areas of expertise.

Methods:

This is a transdisciplinary perspective on infectious complications in ESRD due to monogenic causes, such as autosomal dominant polycystic kidney disease (ADPKD), combining expertise in genomics and immunology.

Key findings:

In ADPKD, infection is a frequent complication manifesting primarily as lower urinary tract infection and less frequently as renal infection. Infectious episodes may be a direct consequence of a specific underlying structural abnormality, for example the characteristic cysts, among others. However, evidence suggests that infectious disease risk is also increased in ESRD due to secondary not-well-understood disease mechanisms. These disease mechanisms may vary depending on the underlying nature of the primary disease. While the infectious disease risk is well documented in ADPKD, there are currently insufficient data on the risk in other monogenic causes of ESRD. WES in combination with novel technologies, such as RNA sequencing and single-cell RNA sequencing, can provide insight into the molecular mechanisms of disease progression in different monogenic causes of CKD/ESRD and may lead to the development of novel risk-stratification profiles in the future.

Limitations:

This is not a systematic review of the literature and the proposed perspective is tainted by the authors’ point of view on the topic.

Implications:

WES in combination with novel technologies such as RNA sequencing may enable us to fully unravel underlying disease mechanisms and secondary disease outcomes in monogenic causes of CKD and better characterize individual risk profiles. This understanding will hopefully facilitate the development of novel targeted therapies.

Immune Responses of HLA Highly Sensitized and Nonsensitized Patients to Genetically Engineered Pig Cells

BACKGROUND

We investigated in vitro whether HLA highly sensitized patients with end-stage renal disease will be disadvantaged immunologically after a genetically engineered pig kidney transplant.

METHODS

Blood was drawn from patients with a calculated panel-reactive antibody (cPRA) 99% to 100% (Gp1, n = 10) or cPRA 0% (Gp2, n = 12), and from healthy volunteers (Gp3, n = 10). Serum IgM and IgG binding was measured (i) to galactose-α1-3 galactose and N-glycolylneuraminic acid glycans by enzyme-linked immunosorbent assay, and (ii) to pig red blood cell, pig aortic endothelial cells, and pig peripheral blood mononuclear cell from α1,3-galactosyltransferase gene-knockout (GTKO)/CD46 and GTKO/CD46/cytidine monophosphate-N-acetylneuraminic acid hydroxylase-knockout (CMAHKO) pigs by flow cytometry. (iii) T-cell and B-cell phenotypes were determined by flow cytometry, and (iv) proliferation of T-cell and B-cell carboxyfluorescein diacetate succinimidyl ester-mixed lymphocyte reaction.

RESULTS

(i) By enzyme-linked immunosorbent assay, there was no difference in IgM or IgG binding to galactose-α1-3 galactose or N-glycolylneuraminic acid between Gps1 and 2, but binding was significantly reduced in both groups compared to Gp3. (ii) IgM and IgG binding in Gps1 and 2 was also significantly lower to GTKO/CD46 pig cells than in healthy controls, but there were no differences between the 3 groups in binding to GTKO/CD46/CMAHKO cells. (iii and iv) Gp1 patients had more memory T cells than Gp2, but there was no difference in T or B cell proliferation when stimulated by any pig cells. The proliferative responses in all 3 groups were weakest when stimulated by GTKO/CD46/CMAHKO pig peripheral blood mononuclear cell.

CONCLUSIONS

(i) End-stage renal disease was associated with low antipig antibody levels. (ii) Xenoreactivity decreased with increased genetic engineering of pig cells. (iii) High cPRA status had no significant effect on antibody binding or T-cell and B-cell response.

Targeting proinflammatory cytokines ameliorates calcifying phenotype conversion of vascular progenitors under uremic conditions in vitro

Severe vascular calcification develops almost invariably in chronic kidney patients posing a substantial risk to quality of life and survival. This unmet medical need demands identification of novel therapeutic modalities. We aimed to pinpoint components of the uremic microenvironment triggering differentiation of vascular progenitors to calcifying osteoblast-like cells. In an unbiased approach, assessing the individual potency of 63 uremic retention solutes to enhance calcific phenotype conversion of vascular progenitor cells, the pro-inflammatory cytokines IL-1β and TNF-α were identified as the strongest inducers followed by FGF-2, and PTH. Pharmacologic targeting of these molecules alone or in combination additively antagonized pro-calcifying properties of sera from uremic patients. Our findings stress the importance of pro-inflammatory cytokines above other characteristic components of the uremic microenvironment as key mediators of calcifying osteoblastic differentiation in vascular progenitors. Belonging to the group of "middle-sized molecules", they are neither effectively removed by conventional dialysis nor influenced by established supportive therapies. Specific pharmacologic interventions or novel extracorporeal approaches may help preserve regenerative capacity and control vascular calcification due to uremic environment.

Vascular Calcification in Chronic Kidney Disease: The Role of Inflammation

Cardiovascular complications are extremely frequent in patients with chronic kidney disease (CKD) and death from cardiac causes is the most common cause of death in this particular population. Cardiovascular disease is approximately 3 times more frequent in patients with CKD than in other known cardiovascular risk groups and cardiovascular mortality is approximately 10-fold more frequent in patients on dialysis compared to the age- and sex-matched segments of the nonrenal population. Among other structural and functional factors advanced calcification of atherosclerotic plaques as well as of the arterial and venous media has been described as potentially relevant for this high cardiovascular morbidity and mortality. One potential explanation for this exceedingly high vascular calcification in animal models as well as in patients with CKD increased systemic and most importantly local (micro)inflammation that has been shown to favor the development of calcifying particles by multiple ways. Of note, local vascular upregulation of proinflammatory and proosteogenic molecules is already present at early stages of CKD and may thus be operative for vascular calcification. In addition, increased expression of costimulatory molecules and mast cells has also been documented in patients with CKD pointing to a more inflammatory and potentially less stable phenotype of coronary atherosclerotic plaques in CKD.

End-stage renal disease, dialysis, kidney transplantation and their impact on CD4+ T-cell differentiation

Premature aging of both CD4⁺ regulatory T (Treg) and CD4⁺ responder-T (Tresp) cells in patients with end-stage renal disease (ESRD) is expected to affect the success of later kidney transplantation. Both T-cell populations are released from the thymus as inducible T-cell co-stimulator-positive (ICOS⁺ ) and ICOS^- recent thymic emigrant (RTE) Treg/Tresp cells, which differ primarily in their proliferative capacities. In this study, we analysed the effect of ESRD and subsequent renal replacement therapies on the differentiation of ICOS⁺ and ICOS^- RTE Treg/Tresp cells into ICOS⁺  CD31^- or ICOS^-  CD31^- memory Treg/Tresp cells and examined whether diverging pathways affected the suppressive activity of ICOS⁺ and ICOS^- Treg cells in co-culture with autologous Tresp cells. Compared with healthy controls, we found an increased differentiation of ICOS⁺ RTE Treg/Tresp cells and ICOS^- RTE Treg cells through CD31⁺ memory Treg/Tresp cells into CD31^- memory Treg/Tresp cells in ESRD and dialysis patients. In contrast, ICOS^- RTE Tresp cells showed an increased differentiation via ICOS^- mature naive (MN) Tresp cells into CD31^- memory Tresp cells. Thereby, the ratio of ICOS⁺ Treg/ICOS⁺ Tresp cells was not changed, whereas that of ICOS^- Treg/ICOS^- Tresp cells was significantly increased. This differentiation preserved the suppressive activity of both Treg populations in ESRD and partly in dialysis patients. After transplantation, the increased differentiation of ICOS⁺ and ICOS^- RTE Tresp cells proceeded, whereas that of ICOS⁺ RTE Treg cells ceased and that of ICOS^- RTE Treg cells switched to an increased differentiation via ICOS^- MN Treg cells. Consequently, the ratios of ICOS⁺ Treg/ICOS⁺ Tresp cells and of ICOS^- Treg/ICOS^- Tresp cells decreased significantly, reducing the suppressive activity of Treg cells markedly. Our data reveal that an increased tolerance-inducing differentiation of ICOS⁺ and ICOS^- Treg cells preserves the functional activity of Treg cells in ESRD patients, but this cannot be maintained during long-term renal replacement therapy.

Ethambutol and isoniazid induced severe neurotoxicity in a patient undergoing continuous ambulatory peritoneal dialysis

Ethambutol (EMB) and isoniazid (INH) are the first-line antituberculosis (anti-TB) drugs. However, their neurotoxicity could cause adverse effect and the patients with end-stage renal disease are especially vulnerable due to the reduction in renal drug clearance. Here, we report a 36-year-old man receiving peritoneal dialysis developed progressive paralysis in lower extremities, vision loss and hoarseness 4 months after anti-TB treatment with INH, EMB and rifapentine because of concomitant pulmonary tuberculosis. A diagnosis of EMB/INH-induced peripheral neuropathy, retrobulbar neuritis and laryngoparalysis was made. The patient's neuropathy gradually improved 2 years after discontinuation of EMB/INH. Since EMB and INH may cause simultaneously severe and complex multineuropathy in dialysis patients, their adverse effects should be closely supervised in dialysis patients.

Proportions of Proinflammatory Monocytes Are Important Predictors of Mortality Risk in Hemodialysis Patients

Despite the continuous progression in dialysis medicine, mortality and the burden of cardiovascular disease (CVD) among hemodialysis patients are still substantial. Substantial evidence suggests that proinflammatory (CD16+) monocytes contribute to the development of atherosclerosis. A cohort of 136 stable hemodialysis patients (follow-up: 6.25 year) was assessed to investigate the association between the proportion of CD16+ monocytes for all-cause and CVD mortalities. The CD16+ monocytes were associated with both mortalities after adjusting for a preexisting CVD history. Compared to the reference group (CD16+ monocytes within [15.6–18.6], the first and second quartile), patients with CD16+ monocytes above the highest quartile level (>21.5) had an adjusted hazard ratio (HR) of 30.85 (95% confidence interval [CI]: 7.12–133.8) for CVD mortality and 5.28 (2.07–13.49) for all-cause mortality, and those with CD16+ monocytes below the lowest quartile ≤15.6), had significantly elevated death risks after 3.5-year follow-up (HR [95% CI]: 10.9 [2.42–48.96] and 4.38 [1.45–13.24] for CV and all-cause mortalities, respectively). The hemodialysis patients with CD16+ monocyte level in a low but mostly covering normal range also portended a poor prognosis. The findings shed some light for nephrologists on future prospects of early recognizing immune dysfunction and improving early intervention outcomes.

Clinical factors influencing mortality risk in hospital-acquired sepsis

BACKGROUND

Identification of factors that confer an increased risk of mortality in hospital-acquired sepsis (HAS) is necessary to help prevent, and improve the outcome of, this condition.

AIM

To evaluate the clinical characteristics and factors associated with mortality in patients with HAS.

METHODS

Retrospective study of patients with HAS in a major Spanish Hospital from 2011 to 2015. Data from adults receiving any of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes associated with sepsis were collected. Those fulfilling the SEPSIS-2 definition with no evidence of infection during the first 48 h following hospitalization were included (N = 196). Multivariate analysis was employed to identify the risk factors of mortality.

FINDINGS

HAS patients were found to have many of the risk factors associated with cardiovascular disease (male sex, ageing, antecedent of cardiac disease, arterial hypertension, dyslipidaemia, smoking habit) and cancer. Vascular disease or chronic kidney disease were associated with 28-day mortality. Time from hospital admission to sepsis diagnosis, and the presence of organ failure were risk factors for 28-day and hospital mortality. Experiencing more than one episode of sepsis increased the risk of hospital mortality. 'Sepsis code' for the early identification of sepsis was protective against hospital mortality.

CONCLUSION

This study identifies several major factors associated with mortality in patients suffering from HAS. Implementation of surveillance programmes for the early identification and treatment of sepsis translate into a clear benefit.

Dendritic Cell Dysfunction in Patients with End-stage Renal Disease

End-stage renal disease (ESRD) with immune disorder involves complex interactions between the innate and adaptive immune responses. ESRD is associated with various alterations in immune function such as a reduction in polymorphonuclear leukocyte bactericidal activity, a suppression of lymphocyte proliferative response to stimuli, and a malfunction of cell-mediated immunity at the molecular level. ESRD also increases patients' propensity for infections and malignancies as well as causing a diminished response to vaccination. Several factors influence the immunodeficiency in patients with ESRD, including uremic toxins, malnutrition, chronic inflammation, and the therapeutic dialysis modality. The alteration of T-cell function in ESRD has been considered to be a major factor underlying the impaired adaptive cellular immunity in these patients. However, cumulative evidence has suggested that the immune defect in ESRD can be caused by an Ag-presenting dendritic cell (DC) dysfunction in addition to a T-cell defect. It has been reported that ESRD has a deleterious effect on DCs both in terms of their number and function, although the precise mechanism by which DC function becomes altered in these patients is unclear. In this review, we discuss the effects of ESRD on the number and function of DCs and propose a possible molecular mechanism for DC dysfunction. We also address therapeutic approaches to improve immune function by optimally activating DCs in patients with ESRD.

Relationship between uric acid and technique failure in patients on continuous ambulatory peritoneal dialysis: a long-term observational cohort study

OBJECTIVES

Uric acid (UA) is the product of purine or nucleotide metabolism via the pathway of xanthine oxidase or xanthine dehydrogenase. Although epidemiological studies assessing the role of UA in cardiovascular disease or mortality have produced inconsistent results, the correlation between UA and technique failure in patients on continuous ambulatory peritoneal dialysis (CAPD) remains to be assessed.

DESIGN

A retrospective cohort study.

SETTING

Patients starting CAPD between 2001 and 2009 in a single centre in Taiwan.

PARTICIPANTS

A total of 371 patients on CAPD.

PRIMARY OUTCOME MEASURES

All-cause and peritonitis-related technique failure.

RESULTS

A cohort of 371 participants (43.9% male) was enrolled in the study with a mean age of 55.7±15.9 years at the start of CAPD. During the study period, technique failure occurred in 41 (34.4%) patients in the hyperuricaemia group compared with 49 (19.4%) in the normouricaemia group (p=0.003). In the multivariate Cox regression models, hyperuricaemia at baseline was significantly associated with both a higher risk of technique failure (HR 1.24; 95% CI 1.09 to 1.42, p=0.001) and peritonitis-related technique failure (HR 1.29; 95% CI 1.07 to 1.57, p=0.008).

CONCLUSIONS

UA was shown to be associated with all-cause and peritonitis-related technique failure in our study. Patients on CAPD with hyperuricaemia should be closely monitored and strategies of increasing survival on CAPD should be taken.

IκB Kinase Inhibitor Attenuates Sepsis-Induced Cardiac Dysfunction in CKD

Patients with CKD requiring dialysis have a higher risk of sepsis and a 100-fold higher mortality rate than the general population with sepsis. The severity of cardiac dysfunction predicts mortality in patients with sepsis. Here, we investigated the effect of preexisting CKD on cardiac function in mice with sepsis and whether inhibition of IκB kinase (IKK) reduces the cardiac dysfunction in CKD sepsis. Male C57BL/6 mice underwent 5/6 nephrectomy, and 8 weeks later, they were subjected to LPS (2 mg/kg) or sepsis by cecal ligation and puncture (CLP). Compared with sham operation, nephrectomy resulted in significant increases in urea and creatinine levels, a small (P<0.05) reduction in ejection fraction (echocardiography), and increases in the cardiac levels of phosphorylated IκBα, Akt, and extracellular signal-regulated kinase 1/2; nuclear translocation of the NF-κB subunit p65; and inducible nitric oxide synthase (iNOS) expression. When subjected to LPS or CLP, compared with sham-operated controls, CKD mice exhibited exacerbation of cardiac dysfunction and lung inflammation, greater increases in levels of plasma cytokines (TNF-α, IL-1β, IL-6, and IL-10), and greater increases in the cardiac levels of phosphorylated IKKα/β and IκBα, nuclear translocation of p65, and iNOS expression. Treatment of CKD mice with an IKK inhibitor (IKK 16; 1 mg/kg) 1 hour after CLP or LPS administration attenuated these effects. Thus, preexisting CKD aggravates the cardiac dysfunction caused by sepsis or endotoxemia in mice; this effect may be caused by increased cardiac NF-κB activation and iNOS expression.

Online Haemodiafiltration Improves Inflammatory State in Dialysis Patients: A Longitudinal Study

Background

Patients undergoing conventional hemodialysis (C-HD) present a greater immuno-inflammatory state probably related to uremia, sympathetic nervous system (SNS) activation and /or membrane bioincompatibility, which could improve with a technique-switching to online hemodiafiltration (OL-HD). The antigen-independent pathway activation of this modified immunologic state turns dendritic cells (DC) into an accurate cell model to study these patients. The aim of this study is to further evaluate the immune-inflammatory state of patients in C-HD assessed by DC maturation.

Methods

31 patients were submitted to C-HD and after 4 months switched to the OL-HD technique. Monocytes-derived DCs from HD patients were cultured in the presence of IL-4/GM-CSF. DC-maturation was evaluated by assessing the maturation phenotype by flow cytometry (FACs). DCs-functional capacity to elicit T-cell alloresponse was studied by mixed leucocyte reaction. Cytokine release was assessed by FACs and SNS was evaluated measuring renalase levels by ELISA.

Results

An up-regulation of maturation markers was observed in C-HD DCs which induced two fold more T cells proliferation than OL-HD DCs. Also, C-HD-mDCs presented with over-production of pro-inflammatory cytokines (IL-6, IL-1β, IL-8, IL-10 and TNF-α) compared with OL-HD-mDC (P<0·05). Results were correlated with clinical data. When SNS was evaluated, hypotension events and blood pressure were significantly lower and renalase levels were significantly higher after conversion to OL-HD. Diabetes mellitus type 2 patients also found beneficial reduction of mDC when converted to OL-HD compared to non-diabetics.

Conclusions

OL-HD could interfere with immuno-inflammatory state in HD patients with an improvement of renalase levels as potential key mediators in the mechanistic pathway of down-regulation of DC maturation.