Eryptosis Is Altered in Peritoneal Dialysis Patients.

BACKGROUND: Red blood cells (RBCs) undergo programmed cell death known as eryptosis. Triggers of eryptosis include increased cytosolic Ca(2+) concentration, oxidative stress, osmotic shock, energy depletion and several uremic toxins. Little is known about the pathogenesis of eryptosis in peritoneal dialysis (PD) patients; furthermore, its relevance in worsening clinical conditions in these patients is still not completely defined. OBJECTIVES: We investigated eryptosis levels in PD patients and its association with inflammatory and clinical parameters. MATERIAL AND METHODS: A total of 46 PD patients and 17 healthy subjects (CTR) were enrolled. All eryptosis measurements were made in freshly isolated RBCs using the flow cytometer. RESULTS: Eryptosis was significantly higher in PD patients than that in CTR (p < 0.001). Eryptosis levels did not differ significantly between PD patients with and without diabetes, with and without hypertension, and with and without cardiovascular disease. Eryptosis showed no significant differences between patients treated with continuous ambulatory PD/automated PD, with Kt/Vurea value ≤1.7 and >1.7, with a negative or positive history of peritonitis. On the contrary, eryptosis showed significantly lower levels in PD patients with weekly creatinine clearance ≥45 L/week/1.73 m2 (2.8%, 1.7-4.9 vs. 5.6%, 5.0-13.5; p= 0.049). Eryptosis showed significantly lower levels in PD patients with residual diuresis (n = 23) than that in patients without (3.7%, 2.6-5.6 vs. 5%, 3.1-16; p = 0.03). In these 23 patients, significant negative correlations between percentage of eryptosis and residual glomerular filtration rate (rGFR; Spearman's rho = -0.51, p = 0.01) and diuresis volume (Spearman's rho = -0.43, p = 0.05) were found. CONCLUSIONS: The present study demonstrated higher eryptosis levels in PD patients compared to corresponding levels in CTR. Furthermore, important PD comorbidity and main PD parameters do not influence eryptosis. Importantly, our data have reported an increase in eryptosis levels with progressive residual diuresis and rGFR loss, probably due to decreased uremic toxins clearance.

Presepsin and Procalcitonin Levels as Markers of Adverse Postoperative Complications and Mortality in Cardiac Surgery Patients.

Backgound: This study was aimed at evaluating the presepsin and procalcitonin levels to predict adverse postoperative complications and mortality in cardiac surgery patients. METHODS: A total of 122 cardiac surgery patients were enrolled for the study. Presepsin and procalcitonin levels were measured 48 h after the procedure. The primary endpoints were adverse renal, respiratory, and cardiovascular outcomes and mortality. RESULTS: Presepsin and procalcitonin levels were significantly higher in patients with adverse renal and respiratory outcome (p < 0.001 and 0.0081). The presepsin levels were significantly higher in patients with adverse cardiovascular outcome (p = 0.023) and the procalcitonin values in patients with sepsis (p = 0.0013). Presepsin levels were significantly higher in patients who died during hospitalization (382 pg/mL, interquartile range [IQR] 243-717.5 vs. 1,848 pg/mL, IQR 998-5,451.5, p = 0.049). In addition, the predictive value for in-hospital, 30-days, and 6-months mortality was higher for presepsin, with a significant difference between the 2 biomarkers (p = 0.025, p = 0.035, p = 0.003; respectively). Presepsin and procalcitonin seem to have comparable predictive value for adverse renal, cardiovascular, and respiratory outcome in cardiac surgery patients. Although a positive trend was notable for presepsin and adverse renal outcome (area under the ROC [receiver operating characteristic] curves [AUC] of 0.760, 95% CI 0.673-0.833 versus procalcitonin: AUC 0.692; 95% CI 0.601-0.773): no statistically significant difference was evident between the AUC of the 2 biomarkers (p = 0.25). CONCLUSIONS: Presepsin and -procalcitonin seem to have comparable predictive value for -adverse renal, cardiovascular, and respiratory outcome in cardiac surgery patients. Also, presepsin possesses a better predictive value for in-hospital, 30-days, and 6-months mortality.

Endotoxin Effects on Cardiac and Renal Functions and Cardiorenal Syndromes.

Gram-negative sepsis is a major cause of morbidity and mortality in critical ill patients. Recent findings in molecular biology and in signaling pathways have enhanced our understanding of its pathogenesis and opened up opportunities of innovative therapeutic approaches. Endotoxin plays a pivotal role in the pathogenesis of multi-organ dysfunction in the setting of gram-negative sepsis. Indeed, heart and kidney impairments seem to be induced by the release of circulating pro-inflammatory and pro-apoptotic mediators triggered by endotoxin interaction with immune cells. These molecules are responsible for cellular apoptosis, autophagy, cell cycle arrest, and microRNAs activation. Therefore, the early identification of sepsis-associated acute kidney injury and heart dysfunction may improve the patient clinical outcome. In this report, we will consider the role of endotoxin in the pathogenesis of sepsis, its effects on both cardiac and renal functions, and the interactions between these 2 systems in the setting of cardiorenal syndromes (CRS), particularly in CRS type 5. Finally, we will discuss the possible role of extracorporeal therapies in reducing endotoxin levels.

Procalcitonin and Interleukin-6 Levels: Are They Useful Biomarkers in Cardiac Surgery Patients?

BACKGROUND/AIM: Cardiac surgery-associated acute kidney injury is an independent predictor of chronic renal disease and mortality. The scope of this study was to determine the utility of procalcitonin (PCT) and plasma interleukin-6 (IL-6) levels in predicting renal outcome and mortality in these patients. METHODS: PCT and plasma IL-6 levels of 122 cardiac surgery patients were measured at 48 h after the surgical procedure. Primary endpoints were adverse renal outcome and mortality. Secondary endpoints were length of stay, bleeding, and number of transfusions. RESULTS: PCT was found to be a better predictor of adverse renal outcome than IL-6. IL-6 seemed to be a better predictor of both 30-day and overall mortality than PCT. Neither PCT nor IL-6 levels were found to be good predictors of intensive care unit stay and bleeding. CONCLUSION: PCT may be considered a good predictor of adverse renal outcome in cardiac surgery patients, whereas IL-6 seems to possess a good predictive value for mortality in this population of patients.

Cellular apoptosis in the cardiorenal axis.

Cardiomyocyte apoptosis plays a pivotal role in the pathogenesis of heart failure. It may be induced by different stimuli, and it seems to be perpetuated by oxidative stress and inflammation. In this scenario, heart failure may trigger various cell-mediated and humoral pathways affecting distant organs, such as kidneys, contributing to higher therapeutic costs, morbidity and mortality. The term Cardiorenal Syndromes describes this condition and represents an important model for exploring the pathophysiology of cardiac and renal dysfunction. In this review, we have analyzed the mechanisms of organ interaction and the role of apoptosis in heart-kidney crosstalk, in particular its role in the pathogenesis of the different types of Cardiorenal Syndromes.

Molecular and Genetic Mechanisms Involved in the Pathogenesis of Cardiorenal Cross Talk.

The term 'cardiorenal syndrome' (CRS) encloses a scenario of clinical interactions in which cardiac and renal dysfunctions coexist. The cross talk between the heart and the kidney is clearly evidenced but not fully understood. Indeed, different factors have been shown to be involved in the pathogenesis of CRS, such as systemic inflammation, oxidative stress, apoptosis and immune dysregulation. Recently, considerable attention has been paid to the role of new alternative mechanisms which may be implicated in the pathogenesis of cardiorenal cross talk. In this review, we will focus on epigenetics, prenatal programming, small noncoding RNAs and extracellular vesicles, aiming to elucidate their possible role in heart and kidney diseases.

Cardiorenal Syndrome Type 5 in Sepsis: Role of Endotoxin in Cell Death Pathways and Inflammation.

BACKGROUND/AIMS: Cardiorenal Syndrome Type 5 (CRS Type 5) is characterized by concomitant cardiac and renal dysfunction in the setting of different systemic disorders, such as sepsis. In this study, we investigated the possible relationship between endotoxin levels, renal cell death and inflammation in septic patients with CRS Type 5. METHODS: We enrolled 11 patients with CRS Type 5. CRS Type 5 was defined according to the current classification system. AKI was defined by Acute Kidney Injury Network (AKIN) criteria. Acute cardiac dysfunction was documented by echocardiography as acute left and/or right ventricular dysfunction leading to decreased ejection fraction. Endotoxin activity was measured by the Endotoxin Activity Assay (EAA). Plasma from CRS Type 5 patients was incubated with renal tubular cells (RTCs) and cell death levels were evaluated. Plasma cytokines levels were measured as well. RESULTS: Accordingly to EAA levels, patients were divided into two groups: 45.4% of patients had low endotoxin activity level (negative EAA), while 54.5% of patients showed high endotoxin activity (positive EAA). RTCs incubated with plasma from EAA positive patients showed significantly higher apoptosis levels and higher caspase-3 activation compared to cells incubated with plasma from EAA negative patients, and a significant positive correlation was observed between EAA levels and RTC apoptosis levels. Furthermore, IL-6 and IFN-γ levels were significantly higher in CRS Type 5 patients with positive EAA. CONCLUSION: Our data suggest a possible relationship between endotoxin levels and renal cell death in septic patients with CRS Type 5. Furthermore, this study highlights the presence of renal apoptosis, the immune deregulation and the strong inflammation in CRS Type 5 patients, especially in those with high endotoxin activity.

The Role of Cell-Free Plasma DNA in Critically Ill Patients with Sepsis.

BACKGROUND: The identification of highly reliable outcome predictors in severe sepsis is important to define disease severity, predict bedside prognosis and monitor response to treatment. Cell-free plasma DNA (cfDNA) has been recently proposed as a possible prognostic marker of clinical outcome in septic patients. In this study, we investigated the prognostic value of cfDNA in patients with sepsis and its possible correlation with caspase-3, IL-6 and IL-18 levels. METHODS: We enrolled 34 patients admitted to the intensive care unit (ICU). Out of these 34, 27 patients were septic and 7 were non-septic. cfDNA was extracted from plasma and quantified by real time PCR. Plasma levels of caspase-3, IL-6 and IL-18 were measured by ELISA. RESULTS: We observed significantly higher levels of cfDNA in septic patients. No significant differences were found between cfDNA levels in patients with Gram+, Gram- and fungal infections. Out of the 27 septic patients, 12 developed acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT), and cfDNA levels resulted to be higher in this group. Out of the 27 septic patients, 11 had a negative outcome during the ICU stay. The cfDNA concentrations at admission were higher in non-survivors than in survivors. Caspase-3, IL-6 and IL-18 levels were significantly higher in septic patients when compared to these levels in non-septic patients and correlated with cfDNA levels. CONCLUSION: cfDNA can be considered a good prognostic marker of clinical outcome in septic patients. Its levels increase in case of AKI complicating sepsis, in particular if CRRT is needed, and are associated with poor outcome. Caspase-3, IL-6 and IL-18 levels are higher in septic patients and correlate to cfDNA concentrations.

Effects of fluid overload on heart rate variability in chronic kidney disease patients on hemodialysis.

BACKGROUND: While fluid overload (FO) and alterations in the autonomic nervous system (ANS) such as hypersympathetic activity, are known risk factors for cardiovascular morbidity and mortality in patients on chronic hemodialysis (HD), their relationship has not been thoroughly studied. METHODS: In this observational study involving 69 patients on chronic HD, FO was assessed by whole body bioimpedance measurements before the midweek HD session and ANS activity reflected by Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. In total, 13 different HRV indices were analyzed, comprising a mixture of time domain, frequency domain and complexity parameters. A correlation analysis was performed between the HRV indices and hydration status indices. Successively, patients were retrospectively assigned to a high FO (H, FO > 2.5 L) or low FO (L, FO ≤ 2.5 L) group and these were further compared also after stratification by diabetes mellitus. Finally, a small number of patients without diabetes with significant and persistent FO were followed up for 3 months post-study to investigate how normalization of fluid status affects HRV. RESULTS: SDANN, VLF, LZC and HF% parameters significantly correlate with FO (correlation coefficients were respectively r = -0.40, r = -0.37, r = -0.28 and r = 0.26, p-value < 0.05). Furthermore, LF% and LF/HF were inversely correlated with hydration status (correlation coefficients were respectively r = -0.31 and r = -0.33, p-value < 0.05). These results indicate an association between FO and reduced HRV, higher parasympathetic activation and reduced sympathetic response to the HD session. Indeed, group H tended to have lower values of SDANN, VLF and LZC, and higher values of HF% than patients in the L group. Finally, there was a trend towards lower LF% measured during the last 30 minutes of HD for the H group versus the L group. Reduction in FO achieved over 3 months by implementation of a strict fluid management plan resulted in an increase of HRV. CONCLUSIONS: Our results suggest that depressed HRV is associated with fluid overload and that normalization of hydration status is accompanied by improved HRV.

Genomics and biological activity of neutrophil gelatinase-associated lipocalin in several clinical settings.

Recent literature has shown that neutrophil gelatinase-associated lipocalin (NGAL) is one of the most interesting and promising biomarkers in case of acute kidney injury. However, several studies indicated that this protein may be applied beyond the boundaries of renal pathophysiology and may be used in other pathophysiological settings since it is also expressed in neutrophils, and respiratory, bowel and prostate epithelia. In this review, we report NGAL genomics and biology and its possible use in several clinical settings. In particular, we review the genomic organization of the NGAL gene, the lipocalin family structure, the interaction between NGAL and ligands, and the induction and expression of NGAL in different conditions.

Cardiorenal syndrome type 4: management.

Cardiorenal syndrome (CRS) type 4, or chronic renocardiac syndrome, has been defined as 'chronic abnormalities in renal function leading to cardiac disease' and recognizes the extreme burden of cardiovascular (CV) disease (CVD) risk in patients with chronic kidney disease (CKD). CKD is common and increasingly recognized as a risk factor for CVD. Although during the past 10 years CV morbidity and mortality have decreased markedly in the general population, their rates still remain high among CKD patients. For this reason, CKD patients should be evaluated thoroughly for CV risk factors which require an aggressive management, given the significant implications of CRS type 4 at both individual and societal level. We will review the management of the most important conventional and nonconventional CVD risk factors related to CKD.

Plasma Cell-Free DNA and Caspase-3 Levels in Patients with Chronic Kidney Disease.

BACKGROUND: Cell-free plasma DNA (cfDNA) is circulating extracellular DNA arising from cell death mechanisms (apoptosis, necrosis, etc.). It is commonly existent in healthy individuals, but its ranks increase in diverse clinical circumstances, such as kidney disease, sepsis, myocardial infarction, trauma and cancer. In patients with advanced chronic kidney disease, cfDNA is connected to inflammation, and it has been associated with higher mortality. Caspase-3 plays a dominant role in apoptosis, a mechanism of programmed cell death involved in the pathogenesis and progression of chronic kidney disease (CKD). The aim of this pilot study was the evaluation of cfDNA levels and caspase-3 concentrations in patients with chronic kidney disease, in order to investigate the potential role of these molecules, deriving from inflammatory and apoptotic mechanisms, in the progression of renal damage. METHODS: We compared cfDNA and caspase-3 levels in 25 CKD patients and in 10 healthy subjects, evaluating their levels based on CKD stage. We also explored correlations between cfDNA and caspase-3 levels in CKD patients and between cfDNA and caspase-3 levels and serum creatinine and urea in this population. RESULTS: We observed that cfDNA and caspase-3 levels were higher in patients with CKD compared to healthy subjects, in particular in patients with advanced renal disease (CKD stage 5). A positive correlation between cfDNA and caspase-3 levels and between cfDNA and caspase-3 and creatinine and urea were also noticed. CONCLUSIONS: Patients with chronic kidney disease show higher levels of cfDNA and caspase-3 levels compared to the control group. Based on these preliminary results, we speculated that the worsening of renal damage and the increase in uremic toxin concentration could be associated with higher levels of cfDNA and caspase-3 levels, thus reflecting the potential role of inflammation and apoptosis in the progression of CKD. Future studies should focus on the validation of these promising preliminary results.

[Ultrasound assessment in renal infections]. / L'ecografia nelle infezioni del rene.

Urinary tract infections (UTIs) are a common clinical problem, especially among women. Ultrasound assessment is indicated in case of complicated UTIs, in particular in children, pregnant women and patients with chronic kidney disease. Even though B-mode imaging alone is rarely diagnostic in case of particular kidney infections such as focal and multifocal acute pyelonephritis, Doppler and power-Doppler (PD) techniques are able to increase its sensitivity. Contrast-enhanced ultrasound (CEUS) further improves the signal-to-noise ratio, thus increasing the diagnostic accuracy of ultrasound in case of renal infectious disease. Recent studies performed on kidney transplant recipients have indeed demonstrated the high sensitivity and specificity of CEUS in diagnosing acute pyelonephritis. Moreover, ultrasonography is a useful diagnostic tool in case of kidney abscesses, emphysematous pyelonephritis, early phases of pyonephrosis, and in the evaluation and monitoring of echinococcal cysts. Ultrasound imaging is less specific in diagnosing xanthogranulomatous pyelonephritis, malacoplakia and renal tuberculosis. Finally, several authors recommend routine ultrasound assessment in HIV patients, given the high incidence of renal complications in this population of patients.

[Parenchymal complications of the transplanted kidney: the role of color-Doppler imaging]. / Le complicanze parenchimali del rene trapiantato: il ruolo dell'eco-color-Doppler.

Kidney transplantation is the treatment of choice for end-stage renal disease, given the better quality of life of transplanted patients when compared to patients on maintenance dialysis. In spite of surgical improvements and new immunosuppressive regimens, part of the transplanted grafts still develop chronic dysfunction. Ultrasonography, both in B-mode and with Doppler ultrasound, is an important diagnostic tool in case of clinical conditions which might impair kidney function. Even though ultrasonography is considered fundamental in the diagnosis of vascular and surgical complications of the transplanted kidney, its role is not fully understood in case of parenchymal complications of the graft. The specificity of Doppler ultrasound is low both in case of acute complications such as acute tubular necrosis, drug toxicity and acute rejection, and in case of chronic conditions such as chronic allograft nephropathy. Single determinations of resistance indices present low diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques including tissue pulsatility index, maximal fractional area and contrast-enhanced ultrasound increase the diagnostic power of ultrasonography in case of parenchymal complications of the transplanted kidney.

Novel Clinical Updates in Uremia.

The progressive loss of kidney function is responsible for the retention of different metabolites due to a decrease in their renal clearance [...].

Eryptosis in Patients with Chronic Kidney Disease: A Possible Relationship with Oxidative Stress and Inflammatory Markers.

Background. Eryptosis is the programmed death of red blood cells; it may contribute to worsening anemia in chronic kidney disease (CKD). In this clinical condition, different factors induce eryptosis, such as oxidative stress, energy depletion and uremic toxins. In our study, we investigated if the progression of CKD may influence erythrocyte death levels and its relationship with oxidative stress and inflammation. Methods. We evaluated eryptosis levels in 25 CKD patients (five for each stage), as well as markers of oxidative stress and inflammation: myeloperoxidase (MPO), copper/zinc superoxide dismutase (Cu/Zn SOD) and interleukin-6 (IL-6) were evaluated in plasma samples. Results. Higher cell death rate was reported in the highest CKD stages (p < 0.05). Furthermore, we divided CKD patients into two groups (eGFR< or ≥60 mL/min/1.73 m2). Patients with eGFR < 60 mL/min/1.73 m2 had higher eryptosis levels (p < 0.001). MPO, CU/Zn SOD and IL-6 resulted significantly differently between groups (p < 0.001). Significant positive correlations were reported between eryptosis and MPO (Spearman's rho = 0.77, p = 0.01) and IL-6 (Spearman's rho = 0.52, p = 0.05) and Cu/Zn SOD. Spearman's rho = 0.6, p = 0.03). Conclusions. In patients with CKD, different factors are involved in the pathogenesis of eryptosis, in particular uremic toxins and oxidative stress and inflammatory markers. The progressive impairment of renal function may be associated with the increase in eryptosis levels, probably due to the accumulation of oxidative stress factors, inflammatory cytokines and uremic toxins.

Eryptosis in Peritoneal Dialysis-Related Peritonitis: The Potential Role of Inflammation in Mediating the Increase in Eryptosis in PD.

Background: Peritonitis and exit site infections are the main complications of patients treated with peritoneal dialysis (PD). Erythrocytes (red blood cells­RBCs) are very sensitive cells, and they are characterized by eryptosis (programmed cell death). The purpose of this research was to assess eryptosis in PD patients with PD-related peritonitis and its connection to inflammatory markers in vivo and in vitro. Material and Methods: In this study, we included 65 PD patients: 34 PD patients without systemic inflammation nor PD-related peritonitis in the previous 3 months, and 31 PD patients with an acute episode of PD-related peritonitis. We measured C-reactive protein (CRP) and cytokine (IL-1ß, IL-6, and IL-18) levels as systemic inflammatory markers. Eryptosis was evaluated by flow cytometric analyses in freshly isolated RBCs. The induction of eryptosis due to in vitro exposure to IL-1ß, IL-6, and IL-18 was verified. Results: Eryptosis was significantly higher in PD patients with peritonitis (9.6%; IQR 4.2−16.7), compared to the those in the other group (2.7%; IQR 1.6−3.9) (p < 0.0001). Significant positive correlations were noticed between eryptosis and CRP, IL-1ß, and IL-6. RBCs, incubated with greater concentrations of all cytokines in vitro, resulted in significantly higher occurrences of eryptosis in comparison with those incubated with lower concentration and with untreated cell (p < 0.05), and for those with extensive exposure (p < 0.05). Conclusion: In conclusion, we investigated a potential relationship between systemic eryptosis and the in vivo and in vitro inflammatory damage of the peritoneal membrane during peritonitis. Thus, the presented results revealed that upregulated inflammatory markers and immune system dysregulation could be the cause of high levels of systemic eryptosis during PD-related peritonitis.

In Vitro Induction of Eryptosis by Uremic Toxins and Inflammation Mediators in Healthy Red Blood Cells.

Eryptosis is the stress-induced RBC (red blood cell) death mechanism. It is known that eryptosis is largely influenced by plasma and blood composition, and that it is accelerated in patients affected by chronic kidney disease (CKD). The aim of this study is to evaluate the eryptosis rate in healthy RBCs treated with different concentration of IL-6, IL-1ß, urea and p-cresol, comparable to plasmatic level of CKD patients, at different time points. We exposed healthy RBCs to increasing concentrations of IL-6, IL-1ß, urea and p-cresol. Morphological markers of eryptosis (cell membrane scrambling, cell shrinkage and PS exposure at RBC surface) were evaluated by flow cytometric analyses. The cytotoxic effect of cytokines and uremic toxins were analyzed in vitro on healthy RBCs at 4, 8 and 24 h. Morphology of treated RBCs was dramatically deranged, and the average cell volume was significantly higher in RBCs exposed to higher concentration of all molecules (all, p < 0.001). Furthermore, healthy RBCs incubated with each molecules demonstrated a significant increase in eryptosis. Cytofluorimetric analysis of eryptosis highlighted significantly higher cell death rate in RBCs incubated with a higher concentration of both cytokines compared with RBCs incubated with a lower concentration (all, p < 0.05). In conclusion, our data show that cytokines and uremic toxins have a harmful effect on RBCs viability and trigger eryptosis. Further studies are necessary to validate these results in vivo and to associate abnormal eryptosis with cytokine levels in CKD patients. The eryptosis pathway could, moreover, become a new promising target for anemia management in CKD patients.

Evaluation of a new polysulfone hemofilter for continuous renal replacement therapy.

New strategies using continuous renal replacement therapy as a tool to achieve immunomodulation in septic acute kidney injury have been proposed. The hypothesis is based on the possibility to remove inflammatory mediators and oxidants in a wide spectrum of molecular weights, thanks to new, highly permeable synthetic membranes. A new polysulfone hemofilter with high permeability and a sharp high cut-off membrane (CUREFLO™; Asahi Kasei Kuraray Medical Co., Ltd., Tokyo, Japan) has been evaluated in this study to assess IL-6 and advanced oxidation protein product removal in critically ill patients undergoing continuous renal replacement therapy. Unit performance, sieving coefficients and clearances were evaluated in fourteen patients undergoing continuous veno-venous hemofiltration and continuous veno-venous hemodialysis.