Prevalence and Management of Chronic Pain, Including Neuropathic Pain, in Dialysis Patients with End-Stage Renal Disease

BACKGROUND Chronic kidney disease (CKD) is a growing global health concern. Chronic pain, as a common symptom of CKD, particularly among patients with end-stage renal disease (ESRD), is influenced by complications, dialysis procedures, and comorbidities. We aimed to evaluate chronic pain and probable neuropathic pain in 96 dialysis patients with ESRD using the Douleur Neuropathique 4 (DN4) questionnaire. MATERIAL AND METHODS A total of 96 patients from a single dialysis center were enrolled for the purpose of this study. ESRD was caused by diseases causing kidney damage, such as diabetes. The average duration of maintenance dialysis was 4.6±5.67 years. Comorbidities, functional and mental assessment, and pharmacological treatment data were collected using a questionnaire. The satisfaction with life scale was also used. Chronic pain was defined as lasting more than 3 months. The DN4 was used to determine the neuropathic component of pain. RESULTS Chronic pain was observed in 63.5% of the study participants, with 47.5% of them reporting the presence of neuropathic pain accompanied by a neuropathic component. Significantly more patients with chronic pain reported mood disorders and reduced life satisfaction, but there was no difference in their activities of daily living-assessed functional status or duration of dialysis. Patients experiencing chronic pain received non-steroidal anti-inflammatory drugs, paracetamol, and opioids. CONCLUSIONS Chronic pain, especially with a neuropathic component, is highly prevalent in patients with CKD, and its treatment remains ineffective. Undiagnosed components of pain can contribute to underdiagnosis and inadequate therapy. Further studies and staff education are needed to address this important issue.

Kidneys in heart failure: Impact of flozins

Chronic kidney disease (CKD) and heart failure (HF) represent two modern diseases of civilization and are closely related. According to the concept of cardio-renal and reno-cardiac syndromes, most patients with CKD are affected by cardiovascular disease (CVD), and CVD (including HF) is one of the factors not only promoting progression of established CKD but also triggering its onset and development. Treatment of CVD and HF in CKD patients remains challenging since CKD patients are characterized by extremely diverse and strongly expressed risk profiles, and the data from well-designed clinical trials addressing this population are scarce. Nevertheless, it seems that most of the drugs used in the treatment of CVD and HF (including beta-blockers, angiotensin-converting enzyme [ACE] inhibitors, angiotensin II receptor blocking agents, mineralocorticosteroid receptor antagonists, and sacubitril/valsartan) are of similar efficacy in patients with glomerular filtration rate (GFR) ranging between 45 and 60 ml/min/1.73 m² (although higher prevalence of side effects may limit their use). The data on cardiovascular (CV) drug efficacy in patients with lower GFR values (i.e. below 30-45 ml/min/1.73 m²) remain limited. In this review, we focused on the efficacy of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in the treatment of CVD and HF in CKD patients with or without diabetes. SGLT2i are clearly cardioprotective in a wide spectrum of estimated GFR although the data for HF patients with respect to urine albumin-creatinine ratio (UACR) are scarce, and for those with significantly reduced estimated GFR are still not available or not convincing, even after completion of large-scale high-quality major cardiovascular outcome trials (CVOT) in type 2 diabetes mellitus (T2DM) or trials with flozins in CKD and HF.

The Role of Sclerostin in Rheumatic Diseases: A Review

Systemic connective tissue disorders constitute a heterogenous group of autoimmune diseases with the potential to affect a range of organs. Rheumatoid arthritis (RA) is a chronic, progressive, autoimmune inflammatory disease affecting the joints. Systemic lupus erythematosus (SLE) may manifest with multiple system involvement as a result of inflammatory response to autoantibodies. Spondyloarthropathies (SpAs) such as ankylosing spondylitis (AS) or psoriatic arthritis (PsA) are diseases characterised by the inflammation of spinal joints, paraspinal tissues, peripheral joints and enthesitis as well as inflammatory changes in many other systems and organs. Physiologically, sclerostin helps to maintain balance in bone tissue metabolism through the Wnt/β-catenin pathway, which represents a major intracellular signalling pathway. This review article aims to present the current knowledge on the role of sclerostin in the Wnt/β-catenin pathway and its correlation with clinical data from RA, SLE, AS and PsA patients.

Pharmacological Nephroprotection in Non-Diabetic Chronic Kidney Disease-Clinical Practice Position Statement of the Polish Society of Nephrology

Chronic kidney disease (CKD) is a modern epidemic worldwide. Introducing renin-angiotensin system (RAS) inhibitors (i.e., ACEi or ARB) not only as blood-pressure-lowering agents, but also as nephroprotective drugs with antiproteinuric potential was a milestone in the therapy of CKD. For decades, this treatment remained the only proven strategy to slow down CKD progression. This situation changed some years ago primarily due to the introduction of drugs designed to treat diabetes that turned into nephroprotective strategies not only in diabetic kidney disease, but also in CKD unrelated to diabetes. In addition, several drugs emerged that precisely target the pathogenetic mechanisms of particular kidney diseases. Finally, the role of metabolic acidosis in CKD progression (and not only the sequelae of CKD) came to light. In this review, we aim to comprehensively discuss all relevant therapies that slow down the progression of non-diabetic kidney disease, including the lowering of blood pressure, through the nephroprotective effects of ACEi/ARB and spironolactone independent from BP lowering, as well as the role of sodium-glucose co-transporter type 2 inhibitors, acidosis correction and disease-specific treatment strategies. We also briefly address the therapies that attempt to slow down the progression of CKD, which did not confirm this effect. We are convinced that our in-depth review with practical statements on multiple aspects of treatment offered to non-diabetic CKD fills the existing gap in the available literature. We believe that it may help clinicians who take care of CKD patients in their practice. Finally, we propose the strategy that should be implemented in most non-diabetic CKD patients to prevent disease progression.

Patterns of Dickkopf-3 Serum and Urine Levels at Different Stages of Chronic Kidney Disease

Dickkopf 3 (Dkk3) is a WNT/β-catenin signaling pathway regulator secreted by tubular epithelial cells upon the influence of different stressors. Recently Dkk3 was described as a biomarker of tubular cell injury and a tool that may estimate the risk of chronic kidney disease (CKD) progression. The data about Dkk3 concentrations at particular stages of CKD are lacking. The aim of this study was to measure serum and urine Dkk3 levels in patients with different 'renal status' and evaluate its role as a biomarker of renal damage. One hundred individuals, aged between 24 and 85 years (mean 53.1 ± 17.1), were enrolled in the study. Five groups of 20 subjects each were recruited based on their kidney function. Serum and urine Dkk3 levels were measured by ELISA. The highest median urinary Dkk3 normalized to urinary creatinine was found in patients with established CKD (7051 pg/mg). It was two times higher in renal transplant patients (5705 pg/mg) than in healthy individuals (2654 pg/mg) and the glomerulonephritis group (2470 pg/mg). Urinary Dkk3 was associated with serum creatinine in participants with established CKD and following transplantation. Our results confirm the potential role of Dkk3 as a biomarker of an ongoing renal injury.

The influence of SGLT2 inhibitors on oxidative stress in heart failure and chronic kidney disease in patients with type 2 diabetes

There is increasing interest in sodium-glucose cotransporter 2 inhibitors (SGLT2i) as not only a new oral glucose-lowering drug class but also one with cardio- and nephroprotective potential. Understanding the underlying mechanisms is therefore of great interest, and postulated benefits have included increased natriuresis, lower blood pressure, increased haematocrit, enhanced cardiac fatty acid utilization, reduced low-grade inflammation, and decreased oxidative stress. In particular, redox homeostasis seems to be crucial in the pathogenesis of heart and kidney disease in diabetes, and there is accumulating evidence that SGLT2i have beneficial effects in this perspective. In this review, we aimed to summarize the potential mechanisms of the influence of SGLT2i on oxidative stress parameters in animal and human studies, with a special focus on heart failure and chronic kidney disease in diabetes mellitus.

Relationship of vitamin D deficiency with cardiovascular disease and glycemic control in patients with type 2 diabetes mellitus: the Silesia Diabetes-Heart Project

INTRODUCTION

Vitamin D (VD) has a pleiotropic effect on many health‑related aspects, yet the results of studies regarding vitamin D deficiency (VDD) and both glycemic control and cardiovascular disease (CVD) are conflicting.

OBJECTIVE

The aim of this work was to determine the prevalence of VDD and its associations with CVD and glycemic control among patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

This was an observational study in T2DM patients recruited at the diabetology clinic in Zabrze, Poland (April-September 2019 and April-September 2020). The presence of CVD was determined based on medical records. Blood biochemical parameters, densitometry, and carotid artery ultrasound examination were performed. Control of diabetes was assessed based on glycated hemoglobin A1c (HbA1c) levels. A serum VD level below 20 ng/ml was considered as VDD.

RESULTS

The prevalence of VDD in 197 patients was 36%. CVD was evident in 27% of the patients with VDD and in 33% of the patients with VD within the normal range (vitamin D sufficiency [VDS]) (P = 0.34). The difference between the groups regarding diabetes control was insignificant (P = 0.05), as for the VDD patients the median value (interquartile range) of HbA1c was 7.5% (6.93%-7.9%), and for VDS patients it was 7.5% (6.56%-7.5%). The VDD patients were more often treated with sodium‑glucose cotransporter‑2 inhibitors (SGLT‑2is) (44% vs 25%; P = 0.01).

CONCLUSIONS

About one‑third of the patients showed VDD. The VDD and VDS groups did not differ in terms of CVD occurrence and the difference in glycemic control was insignificant. The patients with VDD were more often treated with SGLT‑2is, which requires further investigation.

Diabetic peripheral neuropathy is associated with diabetic kidney disease and cardiovascular disease – The Silesia Diabetes-Heart Project

Microvascular complications of diabetes seem to be clustered and put patients at higher risk of developing cardiovascular disease (CVD). This was a questionnaire-based study designed to screen for the presence of diabetic peripheral neuropathy (DPN), defined as the score in the Michigan Neuropathy Screening Instrument (MNSI) above 2, and to evaluate its association with other complication of diabetes, including CVD. There were 184 patients included into the study. The prevalence of DPN in the study group was 37.5%. The regression model analysis revealed that the presence of DPN was significantly associated with the presence of diabetic kidney disease (DKD) (P = 0.0034;) and patient's age (P < 0.0001). Thirty-four patients (49.3%) with MNSI score >2 were diagnosed with CVD in comparison to 24 (20.1%) subjects with MNSI score ≤ 2 (P = 0.00006). In case of having one diabetes complication diagnosed, it is important to screen for others, including macrovascular ones.

Inhibitors of sodium-glucose transport protein 2: A new multidirectional therapeutic option for heart failure patients

Several mechanisms have been suggested to explain positive cardiovascular effects observed in studies with sodium-glucose co-transporter 2 (SGLT2) inhibitors. The reduction in glucose reabsorption in proximal tubuli induced by SGLT2 inhibitors increases urinary glucose and sodium excretion resulting in increased osmotic diuresis and consequently in decreased plasma volume, followed by reduced preload. In addition, the hemodynamic effects of SGLT2 inhibition were observed in both hyper and euglycemic patients. Due to the complex and multidirectional effects induced by SGLT2 inhibitors, this originally antidiabetic group of drugs has been successfully used to treat patients with heart failure as well as for subjects with chronic kidney disease. Moreover, their therapeutic potential seems to be even broader than the indications studied to date.

Serum WNT4 protein as an indicator of chronic glomerulonephritis but not a marker of inflammatory cell infiltration and fibrosis: A preliminary study

BACKGROUND

The WNT signaling pathway contributes to renal fibrosis, which is a hallmark of chronic kidney disease (CKD). Serum concentration of WNT4 could be used to monitor the kidney disease; however, no data have yet been published on the subject.

OBJECTIVES

This study measures WNT4 protein in serum of CKD patients depending on the stage, type of nephropathy, the non-nephrotic (NNP) or nephrotic proteinuria (NP), inflammatory cell infiltration in kidney parenchyma (IIKP), interstitial fibrosis in biopsy and serum creatinine. We also evaluated the usefulness of the serum WNT4 as a marker of fibrosis and IIKP.

MATERIAL AND METHODS

The WNT4 protein level in serum of CKD patients and healthy individuals was measured using enzyme-linked immunoassay (ELISA). Patients' blood biochemical profiles and kidney biopsies were evaluated with common laboratory methods.

RESULTS

The serum level of WNT4 protein was higher in CKD patients (i) regardless of the underlying etiology and at early stages of disease; (ii) with lupus nephritis and Immunoglobulin A (IgA) nephropathy; (iii) without or with a small area of IIKP; and (iv) with a small area covered with fibrosis. No difference was observed between NNP and NP patients. The utility of serum WNT4 as a marker of IIKP and fibrosis was not confirmed. Negative correlations with total and low-density lipoprotein (LDL)-cholesterol were found in CKD and IIKP patients. In patients with serum WNT4 above the median value, serum creatinine was higher. However, no correlation between serum WNT4 and creatinine level was found.

CONCLUSIONS

The observed increase in serum WNT4 protein in the early stages of CKD and in patients diagnosed with immune-mediated glomerular disease may suggest that WNT4 may act as a mediator of inflammation. A certain association with the dysregulation of serum lipid metabolism can also be suspected. Serum WNT4 protein may be considered as the indicator of chronic glomerulonephritis, but not a diagnostic marker of IIKP and fibrosis.

Inflammation and Oxidative Stress in Diabetic Kidney Disease: The Targets for SGLT2 Inhibitors and GLP-1 Receptor Agonists

The incidence of type 2 diabetes (T2D) has been increasing worldwide, and diabetic kidney disease (DKD) remains one of the leading long-term complications of T2D. Several lines of evidence indicate that glucose-lowering agents prevent the onset and progression of DKD in its early stages but are of limited efficacy in later stages of DKD. However, sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor (GLP-1R) agonists were shown to exert nephroprotective effects in patients with established DKD, i.e., those who had a reduced glomerular filtration rate. These effects cannot be solely attributed to the improved metabolic control of diabetes. In our review, we attempted to discuss the interactions of both groups of agents with inflammation and oxidative stress—the key pathways contributing to organ damage in the course of diabetes. SGLT2i and GLP-1R agonists attenuate inflammation and oxidative stress in experimental in vitro and in vivo models of DKD in several ways. In addition, we have described experiments showing the same protective mechanisms as found in DKD in non-diabetic kidney injury models as well as in some tissues and organs other than the kidney. The interaction between both drug groups, inflammation and oxidative stress appears to have a universal mechanism of organ protection in diabetes and other diseases.

FHR-5 Serum Levels and CFHR5 Genetic Variations in Patients With Immune Complex-Mediated Membranoproliferative Glomerulonephritis and C3-Glomerulopathy

Background

Factor H-related protein 5 (FHR-5) is a member of the complement Factor H protein family. Due to the homology to Factor H, the main complement regulator of the alternative pathway, it may also be implicated in the pathomechanism of kidney diseases where Factor H and alternative pathway dysregulation play a role. Here, we report the first observational study on CFHR5 variations along with serum FHR-5 levels in immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G) patients together with the clinical, genetic, complement, and follow-up data.

Methods

A total of 120 patients with a histologically proven diagnosis of IC-MPGN/C3G were enrolled in the study. FHR-5 serum levels were measured in ELISA, the CFHR5 gene was analyzed by Sanger sequencing, and selected variants were studied as recombinant proteins in ELISA and surface plasmon resonance (SPR).

Results

Eight exonic CFHR5 variations in 14 patients (12.6%) were observed. Serum FHR-5 levels were lower in patients compared to controls. Low serum FHR-5 concentration at presentation associated with better renal survival during the follow-up period; furthermore, it showed clear association with signs of complement overactivation and clinically meaningful clusters.

Conclusions

Our observations raise the possibility that the FHR-5 protein plays a fine-tuning role in the pathogenesis of IC-MPGN/C3G.

Contribution of Gut Microbiota-Derived Uremic Toxins to the Cardiovascular System Mineralization

Chronic kidney disease (CKD) affects more than 10% of the world population and leads to excess morbidity and mortality (with cardiovascular disease as a leading cause of death). Vascular calcification (VC) is a phenomenon of disseminated deposition of mineral content within the media layer of arteries preceded by phenotypic changes in vascular smooth muscle cells (VSMC) and/or accumulation of mineral content within the atherosclerotic lesions. Medial VC results in vascular stiffness and significantly contributes to increased cardio-vascular (CV) morbidity, whereas VC of plaques may rather increase their stability. Mineral and bone disorders of CKD (CKD-MBD) contribute to VC, which is further aggravated by accumulation of uremic toxins. Both CKD-MBD and uremic toxin accumulation affect not only patients with advanced CKD (glomerular filtration rate (GFR) less than 15 mL/min/1.72 m², end-stage kidney disease) but also those on earlier stages of a disease. The key uremic toxins that contribute to VC, i.e., p-cresyl sulphate (PCS), indoxyl sulphate (IS) and trimethylamine-N-oxide (TMAO) originate from bacterial metabolism of gut microbiota. All mentioned toxins promote VC by several mechanisms, including: Transdifferentiation and apoptosis of VSMC, dysfunction of endothelial cells, oxidative stress, interaction with local renin–angiotensin–aldosterone system or miRNA profile modification. Several attractive methods of gut microbiota manipulations have been proposed in order to modify their metabolism and to limit vascular damage (and VC) triggered by uremic toxins. Unfortunately, to date no such method was demonstrated to be effective at the level of “hard” patient-oriented or even clinically relevant surrogate endpoints.

Dietary Phosphorus as a Marker of Mineral Metabolism and Progression of Diabetic Kidney Disease

Phosphorus is an essential nutrient that is critically important in the control of cell and tissue function and body homeostasis. Phosphorus excess may result in severe adverse medical consequences. The most apparent is an impact on cardiovascular (CV) disease, mainly through the ability of phosphate to change the phenotype of vascular smooth muscle cells and its contribution to pathologic vascular, valvular and other soft tissue calcification. Chronic kidney disease (CKD) is the most prevalent chronic disease manifesting with the persistent derangement of phosphate homeostasis. Diabetes and resulting diabetic kidney disease (DKD) remain the leading causes of CKD and end-stage kidney disease (ESRD) worldwide. Mineral and bone disorders of CKD (CKD-MBD), profound derangement of mineral metabolism, develop in the course of the disease and adversely impact on bone health and the CV system. In this review we aimed to discuss the data concerning CKD-MBD in patients with diabetes and to analyze the possible link between hyperphosphatemia, certain biomarkers of CKD-MBD and high dietary phosphate intake on prognosis in patients with diabetes and DKD. We also attempted to clarify if hyperphosphatemia and high phosphorus intake may impact the onset and progression of DKD. Careful analysis of the available literature brings us to the conclusion that, as for today, no clear recommendations based on the firm clinical data can be provided in terms of phosphorus intake aiming to prevent the incidence or progression of diabetic kidney disease.

What is the prognostic value of reduced eGFR?

Introduction of the definition and classification of chronic kidney disease (CKD) according to the KDOQI guidelines in 2002 served as a turning point in nephrology. On one hand, the new definition has allowed for the standardization of terminology, on the other hand, however, it has led to a rapid growth in CKD diagnoses. Another issue is the strengthening of the assumption, that diagnosis of CKD is associated with further progressive kidney dysfunction until reaching the end stage renal disease (ESRD). Clinical practice, however, provides evidence that not all patients diagnosed with CKD reach ESRD and eventually require renal replacement therapy (RRT), and in many cases CKD does not progress.

AIM

The aim of the study was to assess practical information for a clinician provided by eGFR and its changes during the follow-up of a patient as regards the RRT prognosis and mortality risk.

MATERIALS AND METHODS

The study group consisted of patients with CKD treated in the regional outpatient clinic. Progression was assessed by determining a linear trend line for eGFR results. Based on its course and the value of the coefficient of determination R2, four types of eGFR trajectories were identified: linear progression type (G2), nonlinear progression type (G1), improvement type (G3), undetermined eGFR change type (G4).

RESULTS

The study group consisted of 65 patients 58.5% females, age mean 69 ± 12.8 years. The mean annual eGFR change in the entire group was -1.67±11.7 ml/min/1.73m2/year. During the study, 6.2% of patients began RRT (hemodialysis), and 9.2% died. Despite the evident tendency towards higher mortality in the group characterized by progression (G1+G2) as compared to the group without progression (G3+G4), the difference did not reach statistical significance (p=0.617). However, the comparison of groups with the baseline eGFR value above and below 45 ml/min/1.73 m2 differentiated the two groups that statistically differed in mortality (p=0.044).

CONCLUSIONS

The baseline eGFR was not a significant predictor of future renal outcomes (ESRD, RRT). However, eGFR below 45 ml/min/ 1.73m2 was associated with a significantly higher mortality risk (p=0.036). Moreover, the groups with the fastest and with improved eGFR were characterized by the highest mortality.

What do we know about biomarkers in diabetic kidney disease?

Diabetic kidney disease (DKD) remains the leading cause of the end-stage renal disease (ESRD) and the most common reason for renal replacement therapy. Research has been carried out for years to find a marker that would enable early identification of people at risk of DKD occurrence, as well as people who will progress from DKD to ESRD. With regard to daily medical practice, the only existing prognostic biomarkers in DKD remain urine albumin-creatinine ratio based on the urinary assessment of albumin and creatinine, and estimated glomerular filtration rate - on the basis of serum creatinine concentration. The development of other biomarkers that would enable the identification of patients at risk of DKD, the stratification of the risk of progression to ESRD, as well as the creation of personalised therapy is currently of great interest. This article discusses selected studies in this field, which have been published in recent years.

An Overview of the Pathophysiology of Vascular Calcification in Chronic Kidney Disease

Abnormalities of calcium–phosphate balance, with subsequent bone metabolism disorders, are among the key and earliest features of chronic kidney disease (CKD). Recently, another consequence of these abnormalities was brought to light—namely, vascular calcification. Most studies performed in patients on dialysis suggest that their vascular calcification is more advanced than that seen in the general population. Furthermore, the progression of vessel wall mineralization is much more dynamic in patients with CKD.

Apart from the commonly assessed factors that promote vascular calcification, such as age, duration of dialysis, or poor control of calcium–phosphate status, several other factors have recently been identified. In the spectrum of substances involved in the regulation of the process of soft-tissue calcification, the most extensively studied in the nephrology literature are bone morphogenetic protein 7, osteoprotegerin, matrix Gla protein, fetuin-A, and the phosphatonins. Better understanding of the mechanisms underlying excess vascular mineralization have led to the development of promising new therapies.

Relationship Between Ubiquitin-Specific Peptidase 18 and Hypertension in Polish Adult Male Subjects: A Cross-Sectional Pilot Study

BACKGROUND Arterial hypertension (HT) is a leading cause of cardiac hypertrophy and heart failure. Ubiquitin-specific peptidase 18 (USP18) has been recently described as a factor that prevents myocardial dysfunction. The present study measured serum USP18 levels in normotensive (n=29), isolated diastolic hypertensive (n=20), and systolic-diastolic hypertensive (n=30) male participants and correlated these results with biochemical parameters that are included in routine assessments of patients with hypertension. MATERIAL AND METHODS Seventy-nine men, aged 24 to 82 years (mean=50.8±11.4 years), were included in the study. None of the participants had ever been treated for HT. Blood and urine parameters were assessed using routine techniques. Serum USP18 levels were measured by enzyme-linked immunosorbent assay. RESULTS The means and 95% confidence intervals (CIs) of USP18 levels in the HT(-), iDHT(+), and HT(+) groups were 69.3 (22.1-116.5) pg/ml, 90.1 (29.0-151.3) pg/ml, and 426.7 (163.1-690.3) pg/ml, respectively. In the HT(+) group, the mean serum USP18 level was 6.2-times higher than in the HT(-) group (p=0.014) and 4.7-times higher than in the iDHT(+) group (p=0.19). The partial correlation analysis that was adjusted for risk factors of arteriosclerosis indicated that USP18 levels were correlated with systolic blood pressure, pulse pressure, and heart rate. CONCLUSIONS This preliminary study found that serum USP18 levels were significantly higher in drug-naive male participants with arterial hypertension compared with normotensive controls. USP18 exerts cardiovascular-protective effects. Elevations of USP18 levels may indicate a counterregulatory process that is engaged during increases in pressure in the left ventricle.

Pure Red Cell Aplasia and Antibody-Mediated Rejection: Double Trouble in 1 Kidney Transplant Recipient Solved by Intravenous Immunoglobulin Infusion: A Case Report

Acquired pure red cell aplasia (PRCA) is characterized by severe normocytic (rarely macrocytic) and normochromic anemia, a low reticulocytes count in peripheral blood, and near absence of erythroid precursors in the bone marrow, with a normal level of erythropoietin. We describe a case of the kidney transplant recipient, diagnosed with PRCA induced with parvovirus B19 infection. Our case demonstrates that although this complication is rare, it should be considered in a differential diagnosis of anemia diagnostics in immunocompromised patients. In our case reduced immune response resulted from post-transplant immunosuppressive therapy. In our patient, apart from infection by parvovirus B19, graft dysfunction due to polyomavirus BK virus infection was also detected together with histologic and serologic features of antibody-mediated renal graft rejection. Considering the entire clinical picture, intravenous immunoglobulin therapy (IVIg) was successfully introduced.

Selected Growth Factors in Peritoneal Dialysis: Their Relationship to Markers of Inflammation, Dialysis Adequacy, Residual Renal Function, and Peritoneal Membrane Transport

Objectives

Markers of chronic inflammation, acute-phase reactants, and growth factors may be concomitantly involved in a number of pathologic processes in the general population and uremic patients. In addition, growth factors may influence peritoneal membrane transport characteristics. However, the association between plasma growth factors, markers of chronic inflammation, and peritoneal membrane transport remains largely unknown. The aim of this study was to evaluate the relationship between plasma levels of selected growth factors [basic fibroblast growth factor (bFGF), transforming growth factor β1 (TGFβ1), vascular endothelial growth factor (VEGF)] and markers of chronic inflammation [interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen] in continuous ambulatory peritoneal dialysis (CAPD) patients. The potential link between the above substances and dialysis adequacy was also explored.

Design

Single-center, cross-sectional study.

Setting

Peritoneal Dialysis Unit, Medical Faculty, Jagiellonian University Hospital, Kraków, Poland.

Patients

32 stable end-stage renal disease patients (13 M, 19 F; mean age 53.6 ± 13.7 years) on CAPD for a median period of 19.5 months. Patients free from signs and symptoms of any inflammatory disease (including peritonitis) for at least 3 months were included into the study. All patients underwent measurements of dialysis dose [Kt/V, weekly creatinine clearance (wCCr)] and peritoneal solute transport using a standard peritoneal equilibration test (PET).

Methods

TGFβ1, bFGF, VEGF, and IL-6 were measured with ELISA, CRP was assayed with immunonephelometry, and fibrinogen with Multifibren U reagent (Dade Behring Marburg GmbH, Marburg, Germany). Nephron 97 for Windows software was used to assess dialysis adequacy.

Results

Significant positive correlations between plasma bFGF and IL-6, as well as fibrinogen concentrations ( R = 0.36, p < 0.05 and R = 0.39, p < 0.05, respectively), were found. VEGF correlated significantly with IL-6 and CRP ( R = 0.65, p < 0.0001 and R = 0.51, p < 0.005, respectively). An association between VEGF and bFGF was also found ( R = 0.59, p < 0.0005). Serum level of TGFβ1 revealed no relationship with any marker of acute-phase activation, remaining growth factors, or dialysis adequacy. Positive correlation between TGFβ1 concentration and dialysate-to-plasma ratio for creatinine in PET ( R = 0.35, p < 0.05) was found. In addition, patients with lower solute transport (low/low-average transporters) had lower serum levels of both bFGF and TGFβ1 compared to patients with higher solute transport. Patients with total wCCr > 60 L/week/m2 were characterized by lower levels of bFGF and IL-6. Serum level of IL-6 and plasma levels of bFGF and VEGF were significantly lower among subjects with residual renal function (RRF) > 2.0 mL/minute.

Conclusions

Our results indicate that systemic inflammation in peritoneal dialysis patients is associated with increased plasma VEGF and bFGF but not TGFβ1. The negative correlation with RRF suggests that either the renal clearance of these cytokines and growth factors may contribute to their elimination, or cytokines and growth factors have a negative impact on RRF. We also suggest an association between serum levels of growth factors tested and peritoneal membrane function.

Association between Gastric Emptying Rate and Nutritional Status in Patients Treated with Continuous Ambulatory Peritoneal Dialysis

♦ Objective

To estimate gastric emptying rate in continuous ambulatory peritoneal dialysis (CAPD) patients, with or without indwelling dialysate, and to evaluate if there is an association between gastric motility and nutritional status.

♦ Design

Single-center cross-sectional study.

♦ Setting

Peritoneal Dialysis Unit, Medical Faculty, Jagiellonian University Hospital, Krakow, Poland.

♦ Patients and Methods

20 end-stage renal disease patients [11 F, 9 M; mean age 50.1 ± 11 years; treated with CAPD for median 13.5 (2 – 61) months] were studied. All patients were nondiabetic and had no comorbidity that might influence gastric motility; nor were they receiving any prokinetic drugs. Gastric emptying rate was estimated with dynamic abdominal scintigraphy, started immediately after complete ingestion of a standard 200-kcal solid meal injected with 99mTc-labeled colloid, activity 40 MBq. Scintigraphy was performed at the rate of 23 images in 4-minute intervals for 92 minutes. Two consecutive procedures — with and without PD fluid — were performed at weekly intervals. As nutritional parameters, protein catabolic rate (PCR) and lean body mass (LBM) (based on urea and creatinine kinetics, respectively), body mass index (BMI), and serum albumin were measured.

♦ Results

All analyzed gastric emptying parameters, measured with or without dialysis fluid, were markedly prolonged in patients compared to values accepted as normal in the local scintigraphy unit. Gastric emptying half-time (T1/2) and percent of initial activity in minute 46 and in minute 92 were 60.5 ± 25.0 minutes, 57.19% ± 17.5%, and 33.8% ± 20.9% with a full peritoneal cavity, and 63.9 ± 28.2 minutes, 59.1% ± 23.9%, and 33.9% ± 24.3% with an empty peritoneal cavity. The T1/2 and percent of initial activity after 46 and 92 minutes for healthy subjects were 39 ± 9 minutes, 45% ± 11%, and 15% ± 6%, respectively. T1/2 without dialysis fluid revealed a negative correlation with LBM and BMI values ( r = –0.5, p < 0.05, and r = –0.56, p < 0.01; respectively). Patients with dialysate-free T1/2 > 40 minutes were characterized by significantly lower serum albumin level compared to subjects with T1/2 < 40 minutes (39.2 ± 2.9 vs 42.9 ± 3.6 g/L, p < 0.05). The values of all gastric emptying parameters measured for an empty abdomen were prolonged in subjects with BMI < 25 kg/m2. No difference was found between patients with and without PD fluid.

♦ Conclusions

Gastric emptying is markedly impaired in CAPD patients compared to healthy subjects. However, the presence of dialysate does not influence it significantly. Gastric emptying rate was negatively associated with the nutritional status of treated subjects. This association can be demonstrated when gastric motility is measured with an empty peritoneal cavity.

Hypertensive kidney disease: a true epidemic or rare disease?

In the industrialized world, hypertension affects approximately 30% of the general population. Hypertensive kidney disease is considered one of the consequences of long-term and poorly controlled hypertension. According to renal databases, it is a leading cause of end‑stage renal failure, second only to diabetic kidney disease. We challenge this dogma by emphasizing lack of specificity of both clinical and morphological presentations of hypertension‑related kidney disease and very low prevalence of hypertensive kidney disease that is diagnosed based on kidney biopsy findings in registries. In most cases of concomitant hypertension and chronic kidney disease (CKD), the sequence of events (ie, which came first, CKD or hypertension) cannot be established. Arterial hypertension plays a role in the pathogenesis of chronic vascular disease and may occasionally lead to arterionephrosclerosis, but its general significance in the evolution of CKD and prevalence among CKD patients appear to be highly overestimated. Studies of the morphology of kidney biopsies have indicated that arterionephrosclerosis, classically considered a morphological equivalent of the clinical term "hypertensive kidney disease"(previously referred to as "hypertensive nephropathy"), most commonly superimposes upon variable chronic renal diseases, even in the absence of elevated blood pressure. To date, no prospective controlled clinical trials have been conducted in primary hypertension patients with renal events as primary endpoints. Data from available clinical trials with renal events that serve as secondary endpoints suggest that lowering blood pressure below current targets may provide additional cardiovascular benefits but may be harmful to the kidneys.

Versatility of USP18 in physiology and pathophysiology

Ubiquitin-specific peptidase 18 (USP18) is a multifunctional protein and its roles are still being investigated. This enzyme removes ubiquitin-like molecules from their substrates and the only known interferon-stimulated gene 15 (ISG15) specific protease. Apart from its enzymatic function, it also inhibits interferon type I and III signalling pathways. USP18 is known to regulate multiple processes, such as: cell cycle, cell signalling and response to viral and bacterial infections. Moreover, it contributes to the development of several autoimmune diseases and carcinogenesis, and recently was described as a cardiac remodelling inhibitor. This review summarizes the current knowledge on USP18 functions, highlighting its contribution to the development of heart failure, given the fact that this disease's etiology is now considered to be inflammatory in nature.

C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy

BACKGROUND

Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors.

RESULTS

One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF.

CONCLUSIONS

In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10-15% of IC-MPGN/C3G patients.

Validation of distinct pathogenic patterns in a cohort of membranoproliferative glomerulonephritis patients by cluster analysis

Background

A novel data-driven cluster analysis identified distinct pathogenic patterns in C3-glomerulopathies and immune complex-mediated membranoproliferative glomerulonephritis. Our aim was to replicate these observations in an independent cohort and elucidate disease pathophysiology with detailed analysis of functional complement markers.

Methods

A total of 92 patients with clinical, histological, complement and genetic data were involved in the study, and hierarchical cluster analysis was done by Ward method, where four clusters were generated.

Results

High levels of sC5b-9 (soluble membrane attack complex), low serum C3 levels and young age at onset (13 years) were characteristic for Cluster 1 with a high prevalence of likely pathogenic variations (LPVs) and C3 nephritic factor, whereas for Cluster 2—which is not reliable because of the small number of cases—strong immunoglobulin G staining, low C3 levels and high prevalence of nephritic syndrome at disease onset were observed. Low plasma sC5b-9 levels, decreased C3 levels and high prevalence of LPV and sclerotic glomeruli were present in Cluster 3, and patients with late onset of the disease (median: 39.5 years) and near-normal C3 levels in Cluster 4. A significant difference was observed in the incidence of end-stage renal disease during follow-up between the different clusters. Patients in Clusters 3–4 had worse renal survival than patients in Clusters 1–2.

Conclusions

Our results confirm the main findings of the original cluster analysis and indicate that the observed, distinct pathogenic patterns are replicated in our cohort. Further investigations are necessary to analyse the distinct biological and pathogenic processes in these patient groups.

Prevalence of Chronic Pain, Particularly with Neuropathic Component, and Its Effect on Overall Functioning of Elderly Patients

Background

The prevalence of chronic pain among the elderly is high (estimated at 25–85%) and may adversely affect their everyday functioning, although it is often unrecognized.

Material/Methods

The aim of this study was to assess the prevalence of chronic pain, especially with the neuropathic component, and its effect on overall functioning of elderly patients. We enrolled 145 subjects older than 60 years (nursing home residents, or patients of outpatient geriatric clinic). Information on co-morbidities, functional and mental status, and medications was obtained using a questionnaire. Chronic pain was defined as lasting >3 months and the presence of neuropathic component was detected using the DN4 Questionnaire (Douleur Neuropathique en Questions).

Results

The mean age of patients was 76±9.68 years. Chronic pain was reported by 78% of participants and 32% reported neuropathic pain with neuropathic component (DN4 score ≥4 points). Patients complaining of chronic pain significantly more often presented mood disorders and lower satisfaction with life (particularly those with the highest pain intensity), with no difference in functional status according to the ADL (Activities of Daily Living) tool. Participants with chronic pain were treated with paracetamol (45%), non-steroidal anti-inflammatory drugs (25%), and opioids (24%).

Conclusions

The prevalence of chronic pain, particularly with neuropathic component, in the elderly population seems to be higher than expected based on previous reports, and its treatment appears to be ineffective. This problem requires further research and dissemination of knowledge on the diagnosis and treatment of chronic pain among health care workers caring for elderly patients on a daily basis.

[Heparin-induced hyperkalaemia - a case report]

Heparins are drugs commonly used in the prevention and treatment of thromboembolic complications. It is also common to be aware of the complications of their use, such as increased risk of bleeding or induction of throbocytopenia. However, it should not be forgotten that in about 7% of patients the use of heparins may lead to the significant hyperkalaemia.

AIM

The aim of this study was to draw attention to the rare, but potentially fatal complication of heparin treatment.

CASE REPORT

Here we present the case of the 85-year-old man with the several co-morbid conditions, who developed hyperkalaemia during hospitalization. Hyperkalaemia was resistant to typical conventional treatment. It occured that the reason for this complication was hypoaldosteronism caused by the use of low molecular weight heparin in the prophylactic dose. Kaliaemia normalization was achieved not until the fludrocortisone was used. Heparin induced hyperkalaemia occurs in about 7-8% treated patients. Therefore, it is not a rare complication, but given the prevalence of heparin use and the potential number of patients with this complication, it is rarely diagnosed. Potentially because hyperkalaemia is usually asymptomatic and because heparin treatment is usually temporal. The reported case of a patient with asymptomatic heparin induced hyperkalaemia proves that in everyday practice we may face this complication, and its diagnosis and proper treatment is possible only if we remember about this risk.

Diagnosis and Treatment of Metabolic Acidosis in Patients with Chronic Kidney Disease - Position Statement of the Working Group of the Polish Society of Nephrology

Metabolic acidosis is commonly found in patients with chronic kidney disease (CKD), and its causes are: impaired ammonia excretion, reduced tubular bicarbonate reabsorption and insufficient renal bicarbonate production in relation to the amount of acids synthesised by the body and ingested with food. As the consequence, numerous metabolic abnormalities develop, which may lead to dysfunction of several organs. In observational studies, it has been found that CKD patients with metabolic acidosis are characterised by faster progression of kidney disease towards end stage kidney failure, and by increased mortality. Results of interventional studies suggest that alkali therapy in CKD patients slows progression of kidney disease. In view of these facts, the members of "The Working Group of the Polish Society of Nephrology on Metabolic and Endocrine Abnormalities in Kidney Diseases" have prepared the following statement and guidelines for the diagnosis and treatment of metabolic acidosis in CKD patients. Measurement of bicarbonate concentration in venous plasma or venous blood to check for metabolic acidosis should be performed in all CKD patients and metabolic acidosis in these patients should be diagnosed when the venous plasma or venous blood bicarbonate concentration is lower than 22 mmol/l. In patients with metabolic acidosis and CKD, oral sodium bicarbonate administration is recommended. The goal of such a treatment is to achieve a plasma or blood bicarbonate concentration equal to or greater than 22 mmol/l.

[Osteoporosis and vascular calcification in rheumatoid arthritis - the role of osteoprotegerin and sclerostin]

Disorders of bone tissue metabolism and increased frequency of cardiovascular diseases are among the well-known, extra-articular complications of rheumatoid arthritis (ra). The mechanisms leading to local and generalized loss of bone tissue as well as those promoting calcification of vessels are similar. Recently, a great interest has aroused among the studies related to the meaning of the RANKL/RANK/OPG system and the Wnt/β-catenin signaling pathway, as biological links between the bone and vascular systems. In the course of ra, lowering of the mineral density of bones and intensification of vascular calcification seem to be associated with the increase of plasma concentration of osteoprotegerin (OPG) and sclerostin - the regulatory proteins of the RANKL/RANK/OPG system and the Wnt/β-catenin pathway. Molecular mechanisms associated with the osteoblasts' activation and repression of bone resorption in the future can become the target of a precise, combination therapy in osteoporosis and calcification changes. The article presents the role of the RANKL/RANK/ OPG system and the Wnt/β-catenin pathway in the pathogenesis of disorders of bone tissue metabolism and calcification of vessels in ra, with particular emphasis on the role of OPG and sclerostin.

Heparin-induced thrombocytopenia as a cause of prolonged low platelet count in a patient with thrombotic thrombocytopenic purpura treated with plasmapheresis

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder belonging to thrombotic microangiopathies (TMA) and is caused by functional deficiency of the ADAMTS-13 metalloproteinase. Plasma exchange (PE) remains the treatment of choice in this disease. Here, were describe the case of a patient who apparently recovered from TTP following multiple sessions of PE, but remained thrombocytopenic. Careful analysis revealed the development of heparin-induced thrombocytopenia (HIT) that precluded platelet count (PLT) normalization. Full normalization of PLT followed discontinuation of PE and low-molecular weight heparin.