IL-6 and IL-17 as potential links between pre-existing hypertension and long-term COVID sequelae in patients undergoing hemodialysis: a multicenter cross-sectional study

Long COVID, characterized by persistent symptoms following acute infection, poses a significant health challenge, particularly for patients with pre-existing chronic conditions such as hypertension. We hypothesized that an increase in the production of interleukins (IL)-6 and IL-17 could serve as a potential mechanism linking pre-existing uncontrolled blood pressure (BP) to the occurrence of long-term COVID sequelae in patients undergoing hemodialysis (HD). This cross-sectional study examined serum IL-6 and IL-17 levels in 80 patients undergoing HD, considering preinfection BP, the presence of long-term COVID sequelae, and the time interval after acute COVID-19 infection, which was either 5 or 10 months. Controlled BP was defined as a 3-month average pre-dialysis BP < 140/90 mmHg and post-dialysis < 130/80 mmHg. The findings suggest that the prevalence of long-term COVID sequelae was significantly higher in patients with uncontrolled BP than in the BP-controlled group. Both IL-6 and IL-17 concentrations were also significantly higher in patients with uncontrolled BP compared with the BP-controlled group. The patients with long-term COVID sequelae had higher IL-6 and IL-17 values than the fully recovered patients at both time points, but their concentrations decreased significantly over time. Further research and prospective studies are warranted to validate these findings.

Gut Microbiota's Oxalate-Degrading Activity and Its Implications on Cardiovascular Health in Patients with Kidney Failure: A Pilot Prospective Study

Background and Objectives: The present study aims to investigate the association between gut microbiota's oxalate-degrading activity (ODA) and the risk of developing cardiovascular disease (CVD) over a three-year follow-up period in a cohort of patients undergoing kidney replacement therapy (KRT). Additionally, various factors were examined to gain insight into the potential mechanisms underlying the ODA-CVD link. Materials and Methods: A cohort of 32 KRT patients and 18 healthy volunteers was enrolled in this prospective observational pilot study. Total fecal ODA, routine clinical data, plasma oxalic acid (POx), serum indoxyl sulfate, lipid profile, oxidative stress, and proinflammatory markers were measured, and the patients were followed up for three years to assess CVD events. Results: The results revealed that patients with kidney failure exhibited significantly lower total fecal ODA levels compared to the healthy control group (p = 0.017), with a higher proportion showing negative ODA status (≤-1% per 0.01 g) (p = 0.01). Negative total fecal ODA status was associated with a significantly higher risk of CVD events during the three-year follow-up period (HR = 4.1, 95% CI 1.4-16.3, p = 0.003), even after adjusting for potential confounders. Negative total fecal ODA status was significantly associated with elevated POx and indoxyl sulfate levels and linked to dyslipidemia, increased oxidative stress, and inflammation, which are critical contributors to CVD. Conclusions: The findings contribute novel insights into the relationship between gut microbiota's ODA and cardiovascular health in patients undergoing KRT, emphasizing the need for further research to elucidate underlying mechanisms and explore potential therapeutic implications of targeting gut microbiota's ODA in this vulnerable population.

Optimal Scheduling in General Multi-Queue System by Combining Simulation and Neural Network Techniques

The problem of optimal scheduling in a system with parallel queues and a single server has been extensively studied in queueing theory. However, such systems have mostly been analysed by assuming homogeneous attributes of arrival and service processes, or Markov queueing models were usually assumed in heterogeneous cases. The calculation of the optimal scheduling policy in such a queueing system with switching costs and arbitrary inter-arrival and service time distributions is not a trivial task. In this paper, we propose to combine simulation and neural network techniques to solve this problem. The scheduling in this system is performed by means of a neural network informing the controller at a service completion epoch on a queue index which has to be serviced next. We adapt the simulated annealing algorithm to optimize the weights and the biases of the multi-layer neural network initially trained on some arbitrary heuristic control policy with the aim to minimize the average cost function which in turn can be calculated only via simulation. To verify the quality of the obtained optimal solutions, the optimal scheduling policy was calculated by solving a Markov decision problem formulated for the corresponding Markovian counterpart. The results of numerical analysis show the effectiveness of this approach to find the optimal deterministic control policy for the routing, scheduling or resource allocation in general queueing systems. Moreover, a comparison of the results obtained for different distributions illustrates statistical insensitivity of the optimal scheduling policy to the shape of inter-arrival and service time distributions for the same first moments.

Oxalate Homeostasis in Non-Stone-Forming Chronic Kidney Disease: A Review of Key Findings and Perspectives

Chronic kidney disease (CKD) is a significant global public health concern associated with high morbidity and mortality rates. The maintenance of oxalate homeostasis plays a critical role in preserving kidney health, particularly in the context of CKD. Although the relationship between oxalate and kidney stone formation has been extensively investigated, our understanding of oxalate homeostasis in non-stone-forming CKD remains limited. This review aims to present an updated analysis of the existing literature, focusing on the intricate mechanisms involved in oxalate homeostasis in patients with CKD. Furthermore, it explores the key factors that influence oxalate accumulation and discusses the potential role of oxalate in CKD progression and prognosis. The review also emphasizes the significance of the gut-kidney axis in CKD oxalate homeostasis and provides an overview of current therapeutic strategies, as well as potential future approaches. By consolidating important findings and perspectives, this review offers a comprehensive understanding of the present knowledge in this field and identifies promising avenues for further research.

The Gut-Peritoneum Axis in Peritoneal Dialysis and Peritoneal Fibrosis

Peritoneal fibrosis is an important cause of peritoneal dialysis (PD) discontinuation worldwide and is associated with high morbidity and mortality rate. Although the era of metagenomics has provided new insights into the interactions between the gut microbiota and fibrosis in various organs and tissues, its role in peritoneal fibrosis has rarely been discussed. This review provides a scientific rationale and points out the potential role of gut microbiota in peritoneal fibrosis. In addition, the interaction between the gut, circulatory, and peritoneal microbiota is highlighted, with an emphasis on the relationship to PD outcomes. More research is needed to elucidate the mechanisms underlying the role of gut microbiota in peritoneal fibrosis and potentially unveil new target options for the management of PD technique failure.

Pre-existing serum indoxyl sulfate and COVID-19 outcomes in patients undergoing hemodialysis: A retrospective cohort study

Patients undergoing hemodialysis (HD) are at increased risk of severe complications from COVID-19 due to compromised immune function and comorbidities. This retrospective study aimed to investigate the association between pre-existing serum indoxyl sulfate (IS) concentrations and COVID-19 outcomes in HD patients. Methods. Data on pre-existing IS and proinflammatory cytokines, such as interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) were extracted from an existing patient database. The patients were followed up for 1.5 years and compared according to median serum IS concentration: low-IS (< 22.2 μg/mL) and high-IS (≥22.2 μg/mL) groups. The primary outcomes focused on assessing the risk and severity of COVID-19 infection. Results. A total of 56 patients aged 62 (56-67) years with a dialysis vintage of 37.5 (30-168) months were included in the analysis. Serum levels of IS were significantly correlated with Kt/V values (p = 0.043), arterial hypertension (p = 0.001), IL-6 (p = 0.023), MCP-1 (p = 0.023), and TNF-α (p = 0.033) concentrations. Elevated serum IS levels were significantly associated with an increased risk of COVID-19 infection (p < 0.0001) and a higher likelihood of hospitalization (p = 0.03). Patients with higher IS levels exhibited more severe lung involvement (p < 0.0001) and a greater need for respiratory support (p = 0.004). A serum IS concentration of 21.5 μg/mL was the optimal threshold for predicting COVID-19 infection in HD patients (sensitivity of 83.4% and specificity of 92.3%, p < 0.0001). Conclusion: Our study highlights the detrimental impact of serum IS on COVID-19 infection and its clinical outcomes in patients undergoing HD. Further research is warranted to elucidate the underlying mechanisms and explore potential therapeutic strategies targeting IS in this population.

One year of the full-scale war in Ukraine and kidney replacement therapy: Where do we stand now? A brief report of the Ukrainian Renal Disaster Relief Committee of the Ukrainian Association of Nephrologists and Kidney Transplant Specialists

The war in Ukraine is now entering its ninth year, and a year has passed since the russian army invaded Ukraine on a large scale. A few months ago, the Ukrainian Renal Disaster Relief Committee of the Ukrainian Association of Nephrologists and Kidney Transplant Specialists was established and began its work to provide immediate support to kidney patients during the war. In this brief report, we present the first data collected on the number of patients receiving kidney replacement therapy, the possibility of enrolling new patients, and the availability of an autonomous electricity and water supply in all regions of Ukraine accessible for communication. In addition, we provide a brief analysis of the dynamics of the regional distribution of patients treated with kidney replacement therapy in the war year.

Long-COVID sequelae are associated with oxidative stress in hemodialysis patients

pathophysiology of long-COVID sequelae in the general population of SARS-CoV-2-infected patients has been shown to be strongly influenced by oxidative stress. However, the potential role of oxidative stress in the development of long-COVID sequelae in hemodialysis patients (HD) has never been investigated. The present study aimed to evaluate the oxidative status of HD patients 3.5 months after SARS-CoV-2 infection in relation to the presence of long-COVID sequelae and the severity of the acute phase COVID-19. Methods. This cross-sectional cohort study included 63 HD patients with a median age of 55 (43-62.5) years and a dialysis vintage of 42 (25-73) months who had been infected with COVID-19 at least 3 months before recruitment. Patients were divided into two groups according to the occurrence of long-COVID sequelae: Group 1 included 31 (49.2%) HD patients with sequelae, while Group 2 included 32 (50.8%) fully recovered individuals. At 3.5 (3.2-4.6) months after the acute phase of COVID-19, malondialdehyde (MDA) and erythrocyte levels (MDAe), sulfhydryl groups (SH -groups), serum catalase activity, transferrin, and ceruloplasmin were measured. A comparison of the obtained data was performed using the Student’s test or the Mann-Whitney test according to the data distribution. A correlation was evaluated with the Spearman test. Results. HD patients with persistent long-COVID sequelae had significantly higher concentrations of MDAs (p = 0.002), MDAe (p = 0.0006), and CTs (p = 0.02), and lower serum levels of SH-groups (p = 0.03) and ceruloplasmin (p = 0.03) compared with Group 2. The concentration of most studied indicators of pro- and antioxidant status did not depend on the severity of the acute phase COVID-19, and only catalase activity was statistically significantly related to the need for hospitalization (r = 0.59; p = 0.001), oxygen support (r = 0.44; p = 0.02), and the percentage of lung injury according to computed tomography (p = 0.03). Although the serum concentration of transferrin did not differ between the studied groups, the individual analysis showed that its value was statistically higher in HD patients with severe COVID-19 even 3.5 months after infection (p < 0.0001). Conclusions. Long-term COVID-19 sequelae in HD patients are associated with oxidative stress. High levels of catalase activity and serum transferrin 3.5 months after COVID-19 may be a consequence of the severe course of the acute phase of the disease. The obtained data suggest that the use of antioxidants may be one of the possible strategies to treat the long-term consequences of COVID in HD patients.  

Recommendations of the Ukrainian Renal Disaster Relief Committee of the Ukrainian Association of Nephrologists and Kidney Transplant Specialists regarding medical care to kidney disease patients during the war

Abstract. The occurrence of an emergency situation (ES) forced international (ISN, EDTA/ERA) and national (Turkey) nephrological associations to establish the Renal Disaster Relief Task Force, which is primarily concerned with the treatment of patients with acute kidney injury and end-stage renal disease requiring dialysis. The war started by the RF is putting the Ukrainian state, Ukrainian society, and the healthcare system in the catastrophic ES. Under these circumstances, all nephrological patients became one of the most vulnerable categories of patients. To provide immediate support in solving problems within the Ukrainian Association of Nephrologists and Kidney Transplant Specialists (UAN&KTS), the Ukrainian Renal Disaster Relief Committee (URDRC) has been established. One of the most important tasks was to form a group of experts to develop recommendations for specialized medical care for kidney patients in wartime.  According to the experts, the key person for this type of medical care is the leading nephrologist in the region or city. He/she establishes a local Renal Disaster Relief Committee (LRDRC) and decides through horizontal (with other LRDRC) or vertical (with UAN &KTS) collaboration, using available communication tools, on the problems that arise; the most appropriate tool is the Viber platform "Nephrology. Dialysis. Transplantation". In this way, a network without administrative subordination and a non-hierarchical functional system was created, which, on the one hand, functions according to similar working principles, but, on the other hand, may differ in terms of LRDRC composition, communication methods, and more. The LRDRC divides all patients into three groups and provides work preparation measures before, during and after the cancellation of ES.

Specialized medical care for chronic kidney disease patients during the war in Ukraine

         Russian invasion is an unprecedented test for the Ukrainian state, Ukrainian society, and the health care system.          According to the Ministry of Health of Ukraine, more than 600 healthcare facilities suffered serious damage (more than 100 hospitals and 450 pharmacies were ruined, and more than 200 emergency medical vehicles were destroyed).          Patients with chronic diseases in the occupied territories and war zones are deprived of medical care and support, which is a direct threat to their lives.          Chronic kidney disease (CKD) patients are one of the most vulnerable groups. Before the war, almost 10,000 patients were treated with dialysis kidney replacement therapy (KRT) and more than 1,500 had a functioning renal graft in Ukraine. The vast majority of patients with end-stage kidney disease receiving dialysis treatment were evacuated to safer regions, and some of them continued the treatment abroad. However, the war will significantly increase the number of patients in need of kidney care. In addition to the existing number of CKD patients, there will be a large group of patients with acute kidney injury (AKI) as a result of polytrauma, bleeding, injuries, or long-term compression syndrome. Currently, we cannot predict the incidence of AKI. However, according to the previously published data (18% - 34.6% of war victims), we should expect a significant increase in the population of CKD patients shortly which will require immediate changes in both organization and staffing of nephrology care. The medical community recognizes the insurmountable difficulties in providing medical support to Ukrainian citizens during the war, in particular patients receiving KRT or kidney recipients. In our opinion, special programs should be created by relevant professional associations together with the institutes of the Ministry of Health of Ukraine and the National Academy of Medical Sciences of Ukraine at both the state and regional levels in all areas. Therefore, we consider it extremely important to establish a committee for the organization of the healthcare system for CKD patients during wartime. The committee could be created within the Ukrainian Association of Nephrologists and Kidney Transplantation Specialists, for example, as the Renal Disaster Relief Task Force established by the International Association of Nephrologists. The main tasks of the committee are to create a consensus of the Ukrainian Association of Nephrologists and Kidney Transplantation Specialists on the management of CKD patients and patients with AKI during the war and the post-war period. On behalf of the Editorial Board of the Ukrainian Journal of Nephrology and Dialysis, we would like to express our sincere gratitude to all health professionals who, at the risk of their own lives, continue to save patients. All members of the Ukrainian nephrological community are doing everything possible and impossible to ensure the most adequate treatment of kidney patients in wartime. Thank you again. We pray for our heroic warriors who fearlessly defend us and defend Ukraine's independence!   Slava Ukraini! Heroiam slava!

Pilot testing for long-term impact of glycerol-induced acute kidney injury on oxalate homeostasis in rats

Abstract. There is a general lack of research on the long-term effects of acute kidney injury (AKI) on oxalate-degrading bacteria (ODB) and their total oxalate-degrading activity (ODA) in fecal microbiota. In the present pilot study, we separately evaluated the changes in the ODB number and their total ODA in fecal microbiota at 3-time points after glycerol-induced AKI. In addition, we assessed the interactions between AKI-induced renal histopathological changes and ODB, total fecal ODA, and plasma and urine oxalate concentrations in rats. Methods. The male Wistar rats (200-300 g, n = 20) on oxalate-free diet were randomly divided into 2 groups. After 24-h of water deprivation, experimental group 1 (n = 10) received an intramuscular injection of 50% glycerol (10 ml/kg of body weight), and group 2 (n = 10) served as a control. The numbers of ODB (incubated in a highly selective Oxalate Medium and determined using the culture method), total fecal ODA and urinary oxalate (UOx) excretion were measured after injection on days 8, 22 and 70. The method of redoximetric titration with a KMnO4 solution was adopted to evaluate total ODA in fecal microbiota. Renal injury was assessed by histopathology examination, serum creatinine plasma oxalic acid (POx) concentration and daily proteinuria levels after removing the animals from the experiment on day 70. Results. After glycerol injection on days 8 and 22, no differences were found in the numbers of ODB, their total fecal ODA, and UOx excretion level between the experimental and control groups. However, after AKI initiation on day 70, the numbers of ODB, total fecal ODA, and daily UOx excretion were significantly lower in the experimental group as compared with the control group. In addition, in 10 weeks following AKI, the number of ODB had a direct correlation with UOx excretion and an inverse correlation with POx and serum creatinine concentrations and daily proteinuria. Total ODA in fecal microbiota was directly associated with the percentage of renal interstitial fibrosis and the average glomerular volumes in the experimental rats. Conclusions: AKI had long-term negative effects on the quantitative and qualitative characteristics of ODB in fecal microbiota in rats. Moreover, the results of our study confirmed an increasing trend in total fecal ODA according to the aggravation of renal interstitial fibrosis and glomerular volume in rats’ kidneys. Further studies are warranted to gain more insight into the mechanism of oxalate homeostasis impairment in AKI.

Peritoneal dialysis and peritoneal fibrosis: molecular mechanisms, risk factors and prospects for prevention

Peritoneal dialysis (PD) leads to structural and functional changes in the peritoneal membrane, the endpoint of which is peritoneal fibrosis. Peritoneal fibrosis is diagnosed in 50% and 80% of PD patients within 1 and 2 years of treatment initiation, respectively. A key role in the development of peritoneal fibrosis is played by mesothelial-mesenchymal transformation, a complex biological process of transition from mesothelium to mesenchyme. This review summarizes the current knowledge on the changes in peritoneal function and morphology, the molecular mechanisms of peritoneal fibrosis development, and its clinical consequences during PD. Special attention is given to established and potential risk factors for peritoneal fibrosis, and existing prevention strategies are considered.

Association of early maladaptive schemas and psychiatric disorders between sex offenders

Introduction

Schema-therapy (ST) - one of the promising integrative models of psychotherapy, which shows its efficacy in many mental disorders. ST has main theoretical concepts: early maladaptive schemas (EMS), coping styles, modes and basic needs. EMS are self-defeating emotional and cognitive patterns established from childhood and repeated throughout life. Existing literature shows the connection between EMS and behavioral problems, which could be more significant for patients with personality disorders. The prevalence of personality disorders is relatively low in the general population, but it’s highly overrepresented in the forensic population, especially in groups of sex offenders.

Objectives

The aim of this study is to examine if there is a prevalence of some EMS between sex offenders and their association with a diagnosed psychiatric disorder.

Methods

Medical records and criminal case materials of 27 patients were reviewed, all of them were blamed for committing sex crimes and had to stay at the department for one month for forensic psychiatry examination. During their stay patients were examined several times and questioned with YSQ S3R.

Results

Most of the patients had psychiatric disorder: specific personality disorders (14), pedophilia (3), dependence syndrome (4), organic personality disorder (3). Some of them had several psychiatric diagnoses. The most prevalent EMS were abandonment, emotional deprivation, insufficient self-control and defectiveness.

Conclusions

These findings show the prevalence of personality disorder and several EMS in sex offenders, which could be useful for the full understanding of the concept of PD and improve the organization of medical care for these individuals.

Disclosure

No significant relationships.

MO682: Serum Total Indoxyl Sulfate is Associated with Intraperitoneal Inflammation and High Peritonitis Episodes in Peritoneal Dialysis Patients

BACKGROUND AND AIMS

The accumulating evidence presented thus far supports the idea that indoxyl sulfate (IS) is a trigger of chronic inflammation in end-stage kidney disease patients. However, although serum IS is one of the most extensively studied uremic toxins, no single study exists which has investigated the association between serum IS and intraperitoneal inflammation in peritoneal dialysis (PD) patients.

The present study was undertaken to evaluate the association between serum total IS (tIS) concentration and the pro-inflammatory markers in peritoneal dialysis effluent (PDE) and peritonitis episodes in PD patients.

METHOD

In this observational cross-sectional study, we analysed serum tIS concentration and 24-h PDE levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein -1 (MCP-1) in 74 PD patients with an average age of 55 (38–64) years and dialysis vintage of 36 (30–58) months. All patients had been undergoing continuous ambulatory PD and had no PD-associated infectious complications for more than 3 months.

Serum concentrations of tIS were determined using the spectrophotometry method. The concentrations of IL-6, TNF-α and MCP-1 in PDE were analysed using ELISA.

For the statistical analysis, we stratified this PD patient cohort into two groups depending on experienced peritonitis: the peritonitis group (n = 48) and the peritonitis-free group (n = 26). The data were presented as the median and the interquartile ranges [Me (Q25–Q75)] and compared using the Kruskal–Wallis test. The Spearmen correlation test was performed to assess the association between IS and the pro-inflammatory markers.

RESULTS

Significant differences were found in serum concentrations of tIS and PDE levels of IL-6 between the peritonitis and the peritonitis-free PD patients (Table 1).

In addition, serum tIS was significantly associated with number of experienced peritonitis episodes (r = 0.26, P = 0.022).

Although PDE levels of TNF-a and MCP-1 did not differ between the peritonitis and the peritonitis-free groups in our cohort, they had a direct association with serum tIS similar to those of IL-6 (Fig. 1, 2).

Moreover, serum tIS was statistically higher in the anuric PD patients compared with the non-anuric patients [33.6 (13.9–74) versus 20.2 (9.3–46) μg/mL, P = 0.043], had a negative association with residual renal function (r = −0.39, P = 0.0017) and, accordingly, total weekly Kt/V (r = −0.27, P = 0.026).

CONCLUSION

Serum tIS concentration has a significant direct association with PDE levels of the pro-inflammatory markers, high peritonitis episodes and their outcomes in PD patients. Further well-designed studies are required to establish the effect of serum tIS concentration on intraperitoneal inflammation and clinical outcomes in PD patients.

MO878: Does Haemodiafiltration Versus Haemodialysis Have Clinical Benefits for Covid-19 Severity and Mortality in Maintenance Haemodialysis Patients?

BACKGROUND AND AIMS

It has been demonstrated that online haemodiafiltration (HDF) provides higher clearance of middle molecular solutes compared with high-flux haemodialysis (HD) due to its convective component and may improve clinical outcomes in maintenance haemodialysis patients. However, the clinical superiority of HDF compared with standard HD is still controversial. Moreover, there is a general lack of these data on the current topic in patients infected with COVID-19. The present study aimed to prospectively analyze whether HDF has benefits for COVID-19 severity and mortality in maintenance haemodialysis patients.

METHOD

A total of 340 maintenance haemodialysis patients aged 53.5 ± 12.9 years and a median dialysis vintage of 40 (24–74) months were included in this prospective multicentre cohort study conducted across 5 dialysis centers. All patients were not infected with COVD-19 at the time of the enrollment and subsequently followed up from March 2020 to September 2021 (the mean duration was 7 (4.2–15.4) months). The study outcomes were COVID-19-associated hospitalization needs due to supplemental oxygen requirements and COVID-19-associated mortality.

The data were presented as the mean and the standard deviation (M ± SD) or the median and the interquartile ranges [Me (Q25–Q75)] and compared using the Student's t-test or the Mann–Whitney U-test as appropriate. The Chi-squared test was used to determine the differences between categorical variables. The univariate logistic regression analyses were performed to evaluate the predictive factors for COVID-19-associated severity and mortality. Then, the Cox proportional-hazards regression model was carried out using the factors found to be significant by the univariate analysis.

RESULTS

Among the enrolled patients, there were 312 (91.7%) patients on HDF and 28 (8.3%) patients treated with HD. Sex (χ² = 1.12 P = 0.29), age (55.3 ± 12.9 versus 59.6 ± 12.5 years; P = 0.07) and dialysis vintage [40 (23–72) versus 45 (29–84) months; P = 0.39] did not differ between the HDF and the HD groups at the study entry. During the follow-up period, 98 out of 312 (31.4%) of the HDF patients and 16 out of 28 (57.1%) of the HD patients were infected with COVID-19 (χ² = 9.6; P = 0.001). Among them, there were 54 out of 98 (55.1%) of the HDF patients and 12 out of 16 (75%) of the HD patients who required hospitalization with oxygen supplementation (χ² = 12.6; P = 0.0004). Out of 98, 4 (4.1%) of the HDF patients and 5 out of 16 (31.2%) of the HD patients died (χ2 = 31.3, P < 0.0001) during the follow-up period. In the univariate logistic regression analysis, older patient age {OR: 1.03, [95% confidence interval (95% CI) 1.01–1.05]}, diabetic status (OR: 2.8, 95% CI 1.4–5.5), long dialysis vintage (OR: 1.07, 95% CI 1.03–1.1), low blood flow (OR: 1.04, 95% CI 1.02–1.08) and HD treatment (OR: 4.1, 95% CI 1.5–11.2) were significantly associated with the requirement of oxygen supplementation. In the Cox regression model adjusted for all mentioned factors, HD treatment was significantly associated with COVID-19 severity and oxygen requirement (Figure 1). However, when we performed the same model to predict COVID-associated mortality, HD treatment lost its significance, and only patient age (P = 0.02) and dialysis vintage (P = 0.004) were significantly associated with reduced survival.

CONCLUSION

The HDF patients required fewer hospitalizations and oxygen support and had a lower mortality rate compared with the HD patients. Although HDF treatment versus HD treatment was significantly associated with better COVID-19 outcomes in our cohort, a predictive conclusion of the study was limited by the small sample size of the HD group and a relatively short follow-up period. Further large-scale studies are needed to determine the role of HDF versus HD in COVID-19-associated severity and mortality in maintenance haemodialysis patients.

MO825: Low High-Density Lipoprotein Level Predicts Covid-19 Severity and Mortality in Haemodialysis Patients

BACKGROUND AND AIMS

Several recent studies have demonstrated the association between low high-density lipoprotein cholesterol (HDL-C) levels and poor outcomes in COVID-19-infected patients. However, there is a general lack of research in this field in the haemodialysis population. Therefore, in the present study, we retrospectively examined the association between HDL-C levels and the risk of developing severe outcomes of COVID-19 infection in haemodialysis (HD) patients.

METHOD

A total of 428 HD patients aged 55 (44–64) years and a dialysis vintage of 44 (21–76.6) months were enrolled in this multicentre retrospective cohort study between March 2020 and September 2021. Baseline HDL-C levels were obtained from electronic health records of the patients in the dialysis centres. (The last measurements were carried out before the COVID-19 onset.) Severe COVID-19-associated pneumonia was estimated based on chest computed tomography (CT) findings of pulmonary involvement and assessed using the following scoring system: (1) indicating <5% involvement, (2) indicating 5%–25% involvement, (3) indicating 26%–49% involvement, (4) indicating 50%–75% involvement and (5) indicating more >75% involvement. The primary and the secondary endpoints were COVID-19-related hospitalization and death, respectively.

The data were presented as the median and the interquartile ranges [Me (Q25–Q75)] and compared using the Kruskal–Wallis test. The Spearmen correlation test was used to assess the association between HDL-C and other markers. The multivariate logistic regression and the receiver operating characteristic (ROC) analyses were performed to evaluate the ability of HDL-C for predicting the severity of COVID-19 infection.

RESULTS

Among 428 enrolled patients, there were 142 (33.2%) patients infected with COVID-19 and 286 (66.8%) patients who had a negative result in COVID-19 PCR tests. A total of 108 (76%) patients of 142 COVID-19 positive patients did not require any oxygen support; 40 patients (28%) were hospitalized, 34 patients (24%) needed oxygen supplements and 16 patients (11.3%) died. The chest CT findings were scored from 2 to 4 in almost all HD patients (99.3%), and only 2 patients had 75% pulmonary involvement. The baseline HDL-C level was significantly lower in the patients with severe COVID-19-associated pneumonia compared with the patients with mild and moderate pneumonia scores (Fig. 1). Moreover, HDL-C was negatively correlated with serum C-reactive protein (CRP) (r = –0.42; P = 0.0002) and D-dimer (r = –0.31; P = 0.001) levels.

In the multivariate logistic regression analysis adjusted for age, diabetes, CRP and D-dimer, HDL-C was found to be associated with COVID-19-related hospitalization {OR: 2.4, [95% confidence interval (95% CI) 1.19–4.7]; P = 0.001} and deaths (OR: 3.1, 95% CI 1.28–5.6; P = 0.008) in the HD patients. The ROC curve analysis demonstrated that the most appropriate cut-off point for baseline HDL-C level for predicting severe COVID-19 prognosis in the HD patients was ≤1.2 2 mmol/L with a sensitivity of 93.7% and a specificity of 63.2%. The area under the ROC curve was 0.83 (95% CI 0.76–0.89; P < 0.0001).

CONCLUSION

HDL-C level ≤1.22 mmol/L was independently associated with a severe COVID-19 prognosis in the cohort of our HD patients. Further research with a greater cohort is needed to confirm this preliminary evidence and validate HDL-C level as a predictive biomarker for COVID-19 severity and mortality in HD patients.

How Advanced Is Our Understanding of the Role of Intestinal Barrier Dysfunction in the Pathogenesis of Recurrent Urinary Tract Infections

A comprehensive understanding of urinary tract infections (UTIs), one of the most common human infections, is required as they are complex and poorly understood diseases. Periurethral and vaginal colonization by rectal flora, with the constant presence of pathogens in the urethra, is the initial step of the recurrent UTIs pathway. Current scientific data describe the genetic, etiological, biological, and behavioral risk factors for recurring UTIs, but they do not include the effect of intestinal barrier function on the disease. Although gut microbiota has been proposed as the main source for UTIs, the cross-talk between intestinal barrier dysfunction and the recurrence of UTIs has not yet been supported by scientific data. In this opinion review, based on published data and the results of our clinical studies, I aimed to outline the possible contribution of intestinal barrier dysfunction to the pathogenesis of recurrent UTIs. I believe that the unanswered questions raised by this review can guide further experimental and controlled studies to clarify the mechanisms underlying the role of intestinal barrier dysfunction in the pathogenesis of recurrent UTIs.

Oxalate Balance in Peritoneal Dialysis Patients: A Potential Role of Dialysis-related Peritonitis

BACKGROUND

Little evidence is available on oxalate balance in peritoneal dialysis (PD) patients.

PATIENTS AND METHODS

We performed a cross-sectional observational pilot study with 62 adult PD patients to document oxalate balance and explore its association with PD-related peritonitis. Plasma oxalate concentration, levels of oxalate excretion in 24-h urine, and peritoneal dialysis effluent were evaluated. The peritoneal oxalate transport status and renal and peritoneal oxalate clearances were calculated according to the PD-related peritonitis history.

RESULTS

PD patients with a history of peritonitis had a statistically significantly lower peritoneal oxalate clearance, daily peritoneal oxalate excretion, and overall oxalate removal rate compared with the peritonitis-free PD patients. They had a 4-fold risk of plasma oxalic acid increase, and even a single episode of dialysis-related peritonitis resulted in plasma oxalate elevation.

CONCLUSION

Peritoneal oxalate clearance plays an important role in oxalate balance in PD patients and, therefore, dialysis-related peritonitis is a significant predictor for hyperoxalemia. Further well-designed clinical trials need to be undertaken before the association between peritonitis and oxalate balance in PD patients is more clearly understood.

Synbiotic supplementation and oxalate homeostasis in rats: focus on microbiota oxalate-degrading activity

The present study aimed (i) to evaluate whether ceftriaxone treatment could affect not only intestinal oxalate-degrading bacteria number but also their total activity to degrade oxalate and influence oxalate homeostasis in rats, (ii) and to estimate the ability of commercially available inulin-contained synbiotic to restore fecal oxalate-degrading activity and ceftriaxone-induced disruption of oxalate homeostasis in rats. Twenty-eight female Wistar rats (200-300 g) were randomly divided into four groups (n = 7). Group 1 was treated with vehicle sterile water (0.1 ml, i.m., 14 days); Group 2 received synbiotic (30 mg/kg, per os, 14 days); Group 3 was treated with ceftriaxone (300 mg/kg, i.m., 7 days); Group 4 was supplemented with ceftriaxone and synbiotic. Oxalate-degrading bacteria number and their total activity, urinary and plasma oxalate concentrations were measured on days 1 and 57 after the treatment withdrawal. The redoximetric titration with KMnO₄ was adopted to evaluate the total oxalate-degrading activity in highly selective Oxalate Medium. Ceftriaxone treatment reduced total fecal oxalate-degrading activity independently on oxalate-degrading bacteria number and increased urinary and plasma oxalate concentrations. The synbiotic had higher oxalate-degrading activity vs probiotics and was able to restore fecal oxalate-degrading activity and significantly decrease urinary oxalate excretion in antibiotic-treated rats. Total fecal oxalate-degrading activity but not oxalate-degrading bacteria number should be thoroughly examined in the future to develop predictive diagnostics methods, targeted prevention and personalized treatment in kidney stone disease. Synbiotic supplementation had a beneficial effect on the total oxalate-degrading activity of gut microbiota, which resulted in decreased UOx excretion in rats.

Post-COVID syndrome in dialysis patients and kidney transplant recipients

Abstract. Patients on maintenance dialysis treatment and kidney transplant recipients who survive coronavirus disease 2019 (COVID-19) are at higher risk of post-COVID syndrome compared to the general population. However, a detailed assessment of the causes, features, and clinical outcomes of the post-COVID syndrome in this patients’ cohort does not yet been established. In this review, we summarize published research on this issue to use these available data to predict the development, treatment and prevention of the post-COVID syndrome in dialysis patients and kidney transplant recipients.

Qualitative Characteristics of Varieties and Lines of Winter Triticale Representing Production and Breeding Interest

The article presents the results of evaluating varieties and lines of winter triticale for various indicators of grain quality, which are of great importance in production and breeding. On average, over the years of research, a higher protein content in grain was found in lines 32/4 (13.33 %) and 29/1 (13.23 %). The studied varieties and lines had a high content of good quality gluten, varying from 24.1 % (line 28/1) to 35.3 % (cultivar Bard). All varieties and lines of winter triticale, except for the Orlik variety, correspond to the first quality group.

Plasma oxalic acid and cardiovascular risk in end-stage renal disease patients: a prospective, observational cohort pilot study

BACKGROUND/AIMS

It was hypothesized that oxalate might be strongly involved in atherogenesis and the inflammatory pathway that could result in an increased risk of cardiovascular disease (CVD) in end-stage renal disease (ESRD) patients. Therefore, this study aimed to address two primary research questions: to characterize the lipid profile and the pattern of pro-inflammatory cytokines according to plasma oxalic acid (POx) concentration in ESRD patients; to evaluate the potential role of elevated POx concentration in the development of CVD risk.

METHODS

A total of 73 participants were enrolled in this prospective, observational cohort pilot study. Among them, there were 50 ESRD patients and 23 healthy volunteers. The lipid profile and the pro-inflammatory cytokines were analyzed according to the distribution of POx concentration into tertiles. After the clinical examination, 29 hemodialysis patients and 21 peritoneal dialysis patients without prevalent CVD were observed for CVD events for 2 years. The Cox regression analysis and a set of different types of sensitivity analyses were used to determine whether elevated POx was associated with an increased risk of CVD.

RESULTS

An increasing trend in the atherogenic lipoprotein fractions and the pro-inflammatory markers as well as a linear decrease in high-density lipoprotein was significantly associated with elevated POx. POx concentration ≥ 62.9 μmol/L was significantly associated with CVD events independently of other examined CVD risk factors.

CONCLUSION

This pilot study firstly demonstrated a potential contribution of POx to atherogenesis, inflammation and CVD risk in ESRD patients.

State Institution ‘Institute of Nephrology of the National Academy of Medical Sciences of Ukraine’: 20 years afterward

Abstract. The Institute of Nephrology of the Academy of Medical Sciences of Ukraine was established in 2001. Since then, the Institute has been constantly evolving and, currently, it is a national scientific, methodological and medical center in the field of nephrology. The achievements of the Institute's staff are recognized in Ukraine and the world scientific community. The article presents an analysis of the results of the Institute's activities for 2001-2021.

High-density lipoproteins and clinical outcomes of COVID-19 in hemodialysis patients: A multicenter, propensity-score matched case-control study

Abstract. A decline in high-density lipoprotein (HDL) has been observed in the general population of COVID-19 infected patients. However, little research has been devoted to this topic in hemodialysis (HD) patients and there is a general lack of data on the association between the baseline HDL level and COVID-19 outcomes in HD patients. The present study aimed to assess the association between baseline HDL levels and the risk of developing severe outcomes of COVID-19 infection in HD patients. Methods. A total of 428 HD patients aged 55 (44-64) years and a dialysis vintage of 44 (21-76.6) months were enrolled in this multicenter propensity-score matched case-control study. After propensity-score matching (1 :1), 142 COVID-19 infected HD patients were compared with 142 HD patients who had never been infected with COVID-19. Propensity scores were estimated with MedCalc software based on potential confounding variables (age, diabetes, dialysis vintage and cardiovascular events). Baseline HDL levels were obtained from electronic health records of the patients (the last measurements were carried out before the COVID-19 onset). The endpoints of the study were COVID-19-related hospitalization, oxygen maintenance, and death. The data were presented as the median and the interquartile ranges [Me (Q25-Q75)] and compared using the Mann-Whitney or Kruskal-Wallis tests, as appropriate. The Spearmen correlation test was used to assess the association between HDL and other markers. The multivariate logistic regression and the receiver operating characteristic (ROC) analyses were performed to evaluate the ability of HDL for predicting the severity of COVID-19 infection. The Cox regression analysis was used to determine the association between HDL and COVID-19-associated mortality. Results. Among 142 patients infected with COVID-19, 40 patients (28%) patients were hospitalized, 34 patients (24%) needed oxygen supplements and 16 patients (11.3%) died. The baseline HDL level was significantly lower in the COVID-19 patients compared with the non-infected patients (1.22 (0.97-1.59) vs 1.52 (1.08-1.85) mmol/L, p = 0.011). Moreover, the baseline HDL level was significantly negatively associated with CT findings of pulmonary involvement (r = -0.76, p < 0.0001) and had a strong inverse correlation with serum C-reactive protein (r = -0.42, p = 0,0002) and D-dimer (r = -0.65, p < 0.0001). The multivariate logistic regression analysis demonstrated that HD patients with HDL concentration <1.22 mmol/l have 3 times higher risk of COVID-19 infection (OR 2.8; 95% CI 1.2; 6.5, p = 0.003).  In the Cox regression analysis adjusted for the patients’ age, diabetic status, dialysis vintage and cardiovascular events, low HDL level (<1.22 mmol/L) was found to be associated with COVID-19-related mortality in the HD patients (χ2 = 9.2, p = 0.002). Conclusions. Baseline low HDL-C level was independently associated with COVID-19 morbidity, severity and mortality in HD patients.

MO692COULD THE RESIDUAL RENAL FUNCTION REMAIN A KEY DETERMINANT OF PLASMA OXALIC ACID CONCENTRATION IN PERITONEAL DIALYSIS PATIENTS?

Background and Aims

Under physiological conditions, the bulk of circulating oxalate (90% to 95%) is ultimately excreted by the kidneys. Under uremic and/or anuric conditions, dialysis is considered to be the main method of oxalate removal. Nevertheless, little evidence is available on oxalate balance in peritoneal dialysis (PD) patients. The present study aimed to evaluate the separate contribution of residual renal and peritoneal oxalate clearances to oxalate balance in PD patients.

Method

We performed a cross-sectional observational study involving 62 PD patients with the average age of 50.5±13.5 years and PD vintage of 37±24 months. Plasma oxalate (POx) concentration, levels of daily urinary (UOx) and peritoneal dialysis effluent oxalate (PDEOx) excretion were evaluated. POx concentration was measured spectrophotometrically using MAK315 kit (Sigma, Spain); UOx and PDEOx concentrations were determined using an oxalate oxidase/peroxidase reagent (BioSystems, Spain). In addition, oxalate transport status (4-hour D/P oxalate ratio), renal oxalate clearance (ROxCL) and peritoneal oxalate clearance (PerOxCL) were calculated.

Results

Among the examined PD patients were 41 (66%) patients with preserved diuresis and 21 (34%) patients with anuria. The anuric PD patients had lower PerOxCL and, accordingly, peritoneal and overall oxalate removal levels compared with the patients with preserved diuresis (Table 1).

Conclusion

The results of our research demonstrated an important role of the residual renal function in oxalate balance in PD patients. However, the decline in RRF could partially (but not completely) contribute to the increase in POx in PD patients. Thus, PerOxCL but not ROxCL could significantly affect oxalate balance in PD patients.

FC 044THE LONG-TERM EFFECTS OF ACUTE KIDNEY INJURY ON INTESTINAL OXALATE-DEGRADING BACTERIA IN RATS

Background and Aims

Gut microbiota is considered an important factor affecting oxalate handling in the intestine. It has been demonstrated that intestinal oxalate secretion provides a complementary route of excretion, and it becomes more evident when kidney function declines. A diversity of gut oxalate-degrading bacteria (ODB) has been hypothesized to play a role in this process. However, there is a general lack of research on the long-term effects of acute kidney injury (AKI) on ODB and their total oxalate-degrading activity (ODA) in fecal microbiota. In this study, we evaluated whether renal dysfunction could affect intestinal ODB and their total ODA in a rat model of glycerol-induced AKI.

Method

The Male Wistar rats (200-300 g, n=20) on oxalate-free diet were randomly divided into 2 groups. After 24-h of water deprivation, Group 1 (n=10) received an intramuscular injection of 50% glycerol (10 ml/kg of body weight), and Group 2 (n=10) served as control. The numbers of ODB (incubated in a highly selective Oxalate Medium and determined using culture method) and total fecal ODA were measured after injection on days 7 and 70. The method of redoximetric titration with a KMnO4 solution was adopted to evaluate total ODA in fecal microbiota; the results were expressed as % of oxalate degradation per 0.01 g of feces.

Renal injury was assessed by histopathological examination, serum creatinine and daily proteinuria levels after removing the animals from the experiment on day 70. Cortical interstitial fibrosis was measured by computerized image analysis on sections stained with picrosirius red. The median (Me) and the interquartile ranges (Q25; Q75) were calculated and compared using the nonparametric Mann-Whitney test. The Spearman correlation coefficient was used to evaluate association between the examined parameters.

Results

The obtained results demonstrated: 1) after glycerol injection on day 7, no differences were found in the numbers of ODB and total fecal ODA between the experimental and control groups: 5.9 (5.4-6.0) vs 6.0 (5.4-6.4) CFU/g, p=0.65 and 2.0 (0.1-5.0) vs 2.5 (2.0-9.0) %/0.01g, p=0.24, respectively; 2) after AKI initiation on day 70, the numbers of ODB and total fecal ODA were significantly lower in Group I compared with control Group II (Fig. 1); 3) the higher percentage of renal interstitial fibrosis was, the higher total fecal ODA occurred in the experimental rats (Fig. 2). In addition, the number of ODB in feces in Group 1 had an inverse association with serum creatinine (r=-0.52, p=0.006) and 24-h proteinuria levels (r=-0.86, p&lt;0.0001).

Conclusion

AKI had the long-term negative effects on the quantitative and qualitative characteristics of ODB in fecal microbiota in rats. Moreover, the results of our study confirmed an increasing trend in total fecal ODA according to the aggravation of renal interstitial fibrosis in rats.

MO311THE ASSOCIATION BETWEEN NEPHROTIC-RANGE PROTEINURIA AND OXALATE METABOLISM VIOLATION IN PATIENTS WITH PRIMARY GLOMERULONEPHRITIS

Background and Aims

There is a general lack of scientific research on oxalate metabolism in primary glomerulonephritis (PGN) patients. The present study aimed to evaluate plasma oxalic acid (POx) concentration and urinary oxalate (UOx) excretion in PGN patients and determine the role of nephrotic syndrome in oxalate metabolism, which has never before been reported.

Method

A total of 100 participants were enrolled in this cross-sectional single-center study, including 76 PGN patients aged 41 ± 1.83 years and 24 healthy volunteers on a free-choice diet who served as a control reference group to evaluate POx concentration. Among the patients were 53 (69.7 %) patients with nephrotic syndrome (NS) and biopsy-proven PGN and 23 (30.3 %) patients with a clinical diagnosis of PGN. All patients were treated according to KDIGO Clinical Practice Guidelines for Glomerulonephritis.

In addition to routine hematological and biochemical tests, POx concentration and UOx excretion were found in all study participants. POx was measured spectrophotometrically using a commercially available kit (MAK315, Sigma, Spain). Daily UOx excretion was determined using an oxalate oxidase/peroxidase reagent (BioSystems, Spain). Urine protein excretion (UPE) was measured in a 24-h urine collection. The glomerular filtration rate (GFR) was calculated using the CKD-EPI formula.

The data were presented as the median and the interquartile ranges [Me (Q25-Q75)] and compared using the Mann-Whitney test. The Spearman correlation test and the partial correlation coefficient were used to evaluate the association between the examined markers.

Results

POx concentration was significantly higher in the patients with PGN compared with the healthy volunteers: 29.9 (14.9-51.7) vs 18.9 (16.2-23.8) µmol/L, p = 0.01. Although the patients with NS demonstrated a statistically higher GFR level compared with the patients with mild proteinuria [70.5 (47-87) vs 50 (22-76.2) mL/min/1.73 m2, p = 0.01], these patients also had the highest POx level (Fig. 1). Moreover, POx concentration was significantly associated with GFR (r = -0.27, p = 0.005), serum phosphate (r = 0.26, p = 0.007) and UPE (Fig. 2) levels. No significant differences were found in UOx excretions between the groups. However, the higher level of UPE was, the higher level of UOx was observed in the PGN patients with NS (Fig. 3). The partial correlation analysis confirmed a strong association between UPE and POx concentration independently of the patients’ age, gender, GFR and serum phosphate levels (r = 0.22, p = 0.04).

Conclusion

Nephrotic-range proteinuria was significantly associated with the elevation of POx concentration and UOx excretion in the PGN patients. More research with a larger cohort is needed to confirm this preliminary evidence and validate NS as a risk factor for oxalate metabolism violation in PGN patients.

Crosstalk between proteinuria, plasma oxalic acid and inflammation in glomerulonephritis patients: an exploratory study

Abstract. In the present exploratory cross-sectional cohort study, we evaluated whether plasma and urine oxalate concentrations in patients with primary glomerulonephritis depend not only on the glomerular filtration rate but also on the proteinuria level and influence the inflammatory response. Methods. We enrolled 100 participants, including 76 patients with glomerulonephritis having chronic kidney disease stage (CKD) 1–3b (69.7% of them with nephrotic syndrome) and 24 healthy volunteers. We excluded patients with diabetes, cardiovascular disease and those with glomerulonephritis with an estimated GFR (eGFR) < 30 mL/min/1.73 m2. In addition to routine hematological and biochemical tests, plasma oxalate concentration, urinary oxalate excretion, and serum interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) levels were assessed in all study participants. Results. We observed that plasma oxalic acid concentration was significantly higher in patients with glomerulonephritis (19.0 [5.9–45.2] µmol/L) than in healthy volunteers (5.5 [3.8–7.3] µmol/L, p < 0.0001). Moreover, nephrotic proteinuria was significantly associated with plasma oxalic acid elevation independent of the patients’ age, sex, glomerular filtration rate, and body mass index (odds ratio = 1.42, 95% confidence interval = 1.13–1.77, p = 0.002). In turn, the increased plasma oxalic acid concentration was associated with high levels of serum IL-6 and MCP-1, which may be cardiovascular risk factors in patients with primary glomerulonephritis. Conclusions. Nephrotic proteinuria was significantly associated with the elevation of plasma oxalic acid concentration and hyperoxaluria in glomerulonephritis patients with CKD stages 1–3b. Plasma oxalate at least partly promotes inflammation, which may be a cardiovascular risk factor in patients with glomerulonephritis in the early stages of CKD. Future studies should recruit at least 156 participants to confirm our preliminary results, validate nephrotic proteinuria as a risk factor for oxalate metabolism violation or determine the role of impaired oxalate homeostasis in clinical outcomes in patients with glomerulonephritis.

A potential role of fecal oxalate-degrading activity in oxalate homeostasis in end-stage renal disease patients; a descriptive pilot study

Introduction: End-stage renal disease (ESRD) patients have significant differences in plasma oxalic acid (POx) concentration under the same treatment conditions. Objectives: In the present study, we adopted the method of redoximetric titration with a KMnO4 solution to evaluate the effect of total fecal oxalate-degrading activity (ODA) on oxalate homeostasis in ESRD patients which has never been reported before. Patients and Methods: A total of 56 participants were enrolled in this cross-sectional pilot study, including 24 healthy volunteers (a control reference group) and 32 ESRD patients. Among the ESRD patients, there were 21 hemodialysis (HD) and 11 peritoneal dialysis (PD) patients. Total ODA in fecal samples as well as POx concentration, daily urinary oxalate (UOx) and PD effluent oxalate excretion were determined. Cohen’s d was computed to calculate the effect size using post-hoc analysis. Results: Total ODA in fecal microbiota ranged from -23 to 24%/0.01 g of feces and was statistically higher in healthy volunteers compared with the ESRD patients. The ESRD patients with positive total fecal ODA status had higher UOx excretion level and lower POx concentration compared with the patients with negative total fecal ODA status. Cohen’s d effect size was 1.99 and 1.05, respectively. Total fecal ODA was an independent risk factor associated with POx elevation in the ESRD patients. Conclusion: Our pilot study firstly demonstrated a potential role of total fecal ODA in oxalate homeostasis in ESRD patients. The results might be useful for determining sample size considerations and providing groundwork for future research projects.

Prevention, diagnosis and management of acute kidney injury: Adapted clinical guidelines of the Ukrainian Association of Nephrologists and Kidney Transplant Specialists

Over the last decade, the paradigm of acute renal injury has been changed fundamentally. Unfortunately, the routine clinical practice in Ukraine demonstrates extremely unsatisfactory awareness of the medical community on these issues. In this regard, the Expert Group of the Ukrainian Association of Nephrologists and Kidney Transplant Specialists has created the Adapted Clinical Guidelines on this important issue to improve the professional expertise of doctors, awareness of patients and their families.

Plasma oxalic acid as a trigger for oxidative processes in end-stage renal disease patients

The present study aimed to evaluate the changes in oxidative stress markers according to the concentration of plasma oxalic acid (POx) in end-stage renal disease (ESRD) patients. Methods. We conducted a cross-sectional observational study involving 72 ESRD patients and 30 relatively healthy individuals who served as a control reference group for evaluation of POx concentration. Among ESRD patients there were 32 hemodialysis (HD) patients and 40 peritoneal dialysis (PD). POx concentration was measured spectrophotometrically using a commercially available kit (MAK315, Sigma, Spain). Malonic dialdehyde (MDA), ceruloplasmin (CP), transferrin (TR), sulfhydryl groups (SH-groups), antioxidant blood capacity (AOC) and total peroxidase activity of erythrocytes (TPA) were measured and the oxidative stress index (OSI) was calculated in all examined patients. Results. A significant increase in POx concentration was observed in ESRD patients compared with healthy volunteers (p < 0.0001). The concentrations of MDA in serum, OSI in erythrocytes and serum of the examined patients were gradually increased, while serum levels of CP, AOC, SH-groups and TPA in erythrocytes, on the contrary, were decreased in accordance with the increasing trend of POx concentrations. Correlation analysis demonstrated a statistically significant direct relationship between POx concentration and MDA (r = 0.57; p <0.0001) and OSI (r = 0.64; p <0.0001). The inverse correlation was determined between POx and antioxidant markers: CP (r = -0.35; p = 0.007), SH-groups in serum (r = -0.3; p = 0.04) and erythrocytes (r = -0.53 ; p <0.0001). Conclusions. The intensity of oxidative-antioxidant balance disorders in the blood of ESRD patients has been associated with the POx concentration: the higher the concentration of POx was the more active oxidative processes and the more pronounced lack of antioxidant protective factors occurred. Further studies are needed to determine the role of POx in the initiation of oxidative stress and chronic inflammation in ESRD patients.

The distribution of microplastics in the surface layer of the Atlantic Ocean from the subtropics to the equator according to visual analysis

This study reports the levels of plastic contamination in the Atlantic Ocean between 35°N and 32°S during the 1st stage of the 79th cruise of the "Akademik Mstislav Keldysh" from December 12, 2019, to January 4, 2020. A subsurface pump system and a Manta net were used for seawater filtration. Twenty-seven samples were visually analyzed with a microscope. It was found that almost every subsurface sample contained potentially plastic particles, which were classified according to their type and size. Plastic fragments were more commonly found in the samples taken from the surface. In the subsurface layer, the majority of the detected particles were fibers. These results also indicate that minimal concentrations of plastics tend to be found near the equator and to the north of the Canary Islands. The maximum microplastic concentrations were found in tropical zones. The obtained results are in good agreement with previous models and field studies.

Serum uric acid and renal survival prognosis in primary glomerulonephritis patients in a retrospective single-center cohort

Introduction: The role of serum uric acid (SUA) concentration in primary glomerulonephritis (PGN) aggravation is currently under active discussion. Objectives: This study primarily aimed to analyze the association between SUA concentration and renal survival prognosis in PGN patients and secondarily to determine whether hyperuricemia is an independent risk factor for reduced glomerular filtration rate (GFR) in the presence of nephrotic syndrome. Patients and Methods: We performed a retrospective observational single-center study involving 344 patients with biopsy-proved or clinically diagnosed PGN with the mean follow-up period of 5.3 [3.8-6.2] years. The rate of annual decline in estimated GFR (eGFR) was used to assess chronic kidney disease progression. Primary outcome measures were eGFR decline or transfer to renal replacement therapy (RRT) during the 5-year follow-up period. Results: There were 78/344 (22.7%) patients who eventually progressed to eGFR <15 mL/min/1.73 m2 or started RRT. In multivariate logistic regression analysis eGFR at diagnosis, proteinuria and hyperuricemia were associated with increased renal risk in PGN patients during the 5-year follow-up period. However, a less significant effect of SUA on rapid eGFR decline was found in the patients with nephrotic-range proteinuria compared with the patients with mild proteinuria. Conclusion: Our study revealed that a higher level of SUA was significantly associated with a greater annual decline in GFR and, consequently, a worse 5-year renal survival prognosis in PGN patients. The effect of hyperuricemia on the risk of rapid CKD progression was greater in PGN patients with mild proteinuria compared with the patients with nephrotic-range proteinuria.

Evaluation of the BAX® System for Detection of Listeria monocytogenes in Foods: Collaborative Study

A multilaboratory study was conducted to compare the automated BAX® system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.

Dyslipidemia and Intraperitoneal Inflammation Axis in Peritoneal Dialysis Patients: A Cross-Sectional Pilot Study

Background

We have hypothesized that the problem of dyslipidemia in peritoneal dialysis (PD) patients lies beyond certain levels of plasma lipoprotein and involves cardiovascular risk, but can also influence the development of chronic intraperitoneal inflammation.

Objectives

The aim of our work was to define whether the association of dyslipidemia with intraperitoneal inflammation really exists and if it could it be used in a prospective cohort of PD patients.

Patients and Methods

We performed a cross-sectional, single-center, pilot study involving 40 nondiabetic PD patients (27 men and 13 women with an average age of 49.3 ± 12.2 years). The median time on PD was 29 (18.5-37) months. The parameters dialysis adequacy, blood lipid profile, and the concentrations of tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, and interleukin (IL)-10 in peritoneal dialysate effluent (PDE) were determined. Cohen's d effect size was computed post hoc to determine the differences between groups in the concentrations of pro- and anti-inflammatory mediators.

Results

PD patients with atherogenic dyslipidemia had significantly high levels of MCP-1 compared with dyslipidemia-free patients (Cohen's d = 1.32). A reduced high-density lipoprotein cholesterol level was associated with a high intraperitoneal production of the proinflammatory mediator TNF-α (p < 0.0001) and anti-inflammatory IL-10 (p < 0.0001). Atherogenic index of plasma was directly correlated with MCP-1 (p < 0.0001) and TNF-α (p < 0.0001). In multiple regression analysis, MCP-1 appeared to predict PD inadequacy (R ² = 0.58; F ratio = 9.4; p = 0.006) independently of age and blood C-reactive protein level. Effect size was 1.38 with α = 0.05, n = 40, and 3 predictors.

Conclusions

Our cross-sectional pilot study first demonstrated a close interaction between the atherogenic lipid profile and a high concentration of MCP-1 in PDE; this might be a prognostic marker for PD inadequacy. The potential significance of our finding is that it provides useful preliminary information necessary for further research into this area.

Oxidative Stress in Peritoneal Dialysis Patients: Association with the Dialysis Adequacy and Technique Survival

Introduction:

Increased oxidative stress is suggested as one of the possible mechanisms of structural and functional damage to the peritoneal membrane in peritoneal dialysis patients. But there are few available data on the association of oxidative stress with peritoneal dialysis adequacy and technique survival. The present study was undertaken to investigate the association of oxidative stress biomarkers with the peritoneal dialysis adequacy and technique survival.

Methods:

This prospective single-center observational study was conducted between January 2010 and May 2015. Adequacy of dialysis, malondialdehyde levels in the serum and erythrocytes (as an indicator of lipid peroxidation), the concentration of ceruloplasmin, transferrin, and sulfhydryl groups in the blood, and total peroxidase activity in erythrocyte (as indicators of antioxidant system) were determined in 44 stable ambulatory non-diabetic peritoneal dialysis patients.

Results:

The follow-up period was 3 years. We identified a negative correlation between the serum level of malondialdehyde in the patients and total weekly Kt/V. Peritoneal weekly CrCl was positively correlated with the levels of transferrin, total peroxidase activity, and SH– groups. Daily peritoneal ultrafiltration had a positive correlation with the total peroxidase activity and the serum transferrin levels. The results of the Kaplan–Meier analysis and the log-rank test also demonstrated a significant difference in the cumulative technique survival rate between the patients with ceruloplasmin level ≤0.19 g/l and ≥0.2 g/l.

Conclusions:

The results mentioned above could be considered as one of the ways to explain better technique survival in PD patients.

Association between Dyslipidemia and Peritoneal Dialysis Technique Survival

BACKGROUND:

A large body of research has investigated the effects of pro-atherogenic lipid profile on cardiovascular diseases (CVD) in peritoneal dialysis (PD) patients. However, there is a general lack of research on the association between atherogenic dyslipidemia and PD technique survival.

AIM:

The study aimed to define the association between dyslipidemia and PD technique survival.

METHODS:

It was a prospective single-centre observational study involving 40 outpatients on continuous ambulatory PD treatment for more than 3 months between 2010 and 2016 in a single centre in Ukraine. There were 27 males and 13 females. The mean age of the participants was 49.3 ± 12.2 years. The primary outcome measures were all-cause technique failure.

RESULTS:

Atherogenic dyslipidemia was identified in 28/40 (70 %) patients and correlated with PD adequacy parameters. During the 36-month- follow-up period technique failure occurred in 2/12 (16.6 %) patients with atherogenic dyslipidemia compared with 12 / 28 (42.9 %) patients without atherogenic dyslipidemia (χ² = 2.5; p = 0.12). In the univariate Cox regression model, atherogenic dyslipidemia at baseline was significantly associated with a higher risk of all-cause PD technique failure (HR 4.5; 95% CI 1.6 to 12.9; χ² = 5.5, p = 0.019).

CONCLUSION:

The presence of atherogenic dyslipidemia was significantly associated with a higher risk of technique failure in PD patients. This is an important issue for future research. Further well-designed clinical trials are needed to determine the impact of dyslipidemia on PD adequacy and technique survival.