Identification of inflamed atherosclerotic plaque using 123 I-labeled interleukin-2 scintigraphy in high-risk peritoneal dialysis patients: a pilot study

BACKGROUND

Patients with end-stage renal disease (ESRD) suffer from markedly increased cardiovascular morbidity and mortality. Common carotid artery (CCA) intima-media thickness (IMT) assessment and CCA plaque identification using ultrasound are well-recognized tools for identification and monitoring of atherosclerosis. A new method for monitoring the inflammatory status of plaque, namely radiolabeled interleukin-2 (IL-2) scintigraphy, was proposed recently. The aim of this pilot study was to perform (123)I-labeled-IL-2 carotid plaque scintigraphy in ESRD patients treated with peritoneal dialysis and to correlate obtained results with ultrasound assessment of CCA and selected inflammatory markers.

METHODS

CCA-IMT was measured and CCA plaques were identified by ultrasound in 10 patients (5 women, 5 men; mean age 62.4 +/- 10.4 years; median peritoneal dialysis duration 32.5 months, range 12 - 55 months) with advanced cardiovascular comorbidity. Following CCA ultrasound, (123)I-labeled IL-2 carotid plaque scintigraphy was performed. Several biomarkers of inflammation and atherosclerosis were also measured in all patients.

RESULTS

Mean target/non-target ratio for focal (123)I-IL-2 uptake within the plaque was 3.15 +/- 0.54, and mean IMT from the site of the scintigraphy analysis was 0.975 +/- 0.337 mm. Highly significant correlation was found between CCA-IMT and a target/non-target ratio for focal (123)I-IL-2 uptake in a corresponding artery (R = 0.92, p = 0.01). However, no significant correlations were found between target/non-target ratio for focal (123)I-IL-2 uptake and levels of measured biomarkers.

CONCLUSIONS

Our preliminary results suggest potential for identification of an inflamed (vulnerable) plaque using IL-2 scintigraphy in ESRD patients with cardiovascular comorbidities.

Identification of Inflamed Atherosclerotic Plaque using 123I-Labeled Interleukin-2 Scintigraphy in High-Risk Peritoneal Dialysis Patients: A Pilot Study

Background

Patients with end-stage renal disease (ESRD) suffer from markedly increased cardiovascular morbidity and mortality. Common carotid artery (CCA) intima-media thickness (IMT) assessment and CCA plaque identification using ultrasound are well-recognized tools for identification and monitoring of atherosclerosis. A new method for monitoring the inflammatory status of plaque, namely radiolabeled interleukin-2 (IL-2) scintigraphy, was proposed recently. The aim of this pilot study was to perform 123I-labeled-IL-2 carotid plaque scintigraphy in ESRD patients treated with peritoneal dialysis and to correlate obtained results with ultrasound assessment of CCA and selected inflammatory markers.

Methods

CCA-IMT was measured and CCA plaques were identified by ultrasound in 10 patients (5 women, 5 men; mean age 62.4 ± 10.4 years; median peritoneal dialysis duration 32.5 months, range 12 – 55 months) with advanced cardiovascular comorbidity. Following CCA ultrasound, 123I-labeled IL-2 carotid plaque scintigraphy was performed. Several biomarkers of inflammation and atherosclerosis were also measured in all patients.

Results

Mean target/non-target ratio for focal 123I-IL-2 uptake within the plaque was 3.15 ± 0.54, and mean IMT from the site of the scintigraphy analysis was 0.975 ± 0.337 mm. Highly significant correlation was found between CCA-IMT and a target/non-target ratio for focal 123I-IL-2 uptake in a corresponding artery ( R = 0.92, p = 0.01). However, no significant correlations were found between target/non-target ratio for focal 123I-IL-2 uptake and levels of measured biomarkers.

Conclusions

Our preliminary results suggest potential for identification of an inflamed (vulnerable) plaque using IL-2 scintigraphy in ESRD patients with cardiovascular comorbidities.

Renal artery stenosis in patients with coronary artery disease

BACKGROUND

Renal dysfunction is an important factor of cardiovascular risk. Renal artery stenosis (RAS) is a potential cause of secondary hypertension and by renal ischemia may lead to progressive renal insuficiency. In RAS patients a significant increase in prevalence of coronary artery disease (CAD) as well as revascularisation rate and mortality rate was observed.

AIM

To determine the prevalence of RAS in patients with suspected CAD.

METHODS

The study group consisted of 1036 consecutive patients (700 men; 67.6% ) in the mean age of 62.1+/-9.7 (25-85) years admitted to coronary angiography. Simultaneously renal angiography was performed in all patients.

RESULTS

Stenosis > or = 50% in at least one main branch of coronary artery was found in 633 (66.1%) patients. The proportion of patients with one, two or three vessel CAD was respectively 291 (46%), 169 (26%) and 173 (27.3%). Non-significant coronary lesions <50% were found in 108 (10.4%) patients, whereas in 295 (28.5%) patients no angiographic evidence of CAD was documented. In the whole group of patients RAS was found in 339 (32.7%) of patients - 124 (12%) had bilateral lesions. RAS prevalence in patients with CAD was 38.3% (284/741) and its frequency increased with severity of CAD: from 25% (27/108) in patients with insignificant coronary lesions up to 36.4% (106/291), 40.2% (68/169) and 48% (83/173) in 1, 2, and 3-vessel disease, respectively (p <0.001). RAS prevalence in patients with normal coronary arteries was 18.6% (55/295). RAS <30% was detected in 194 (18,7%) patients; RAS between 30-49% in 81 patients (8.7%); RAS 50-69% in 38 patients (3.7%) and RAS > or = 70% in the remaining 26 patients (2.5%). RAS > or = 50% was noted in 8 (2.7%) patients without coronary lesions; in 5 (4.6%) with insignificant coronary artery atherosclerosis and 51 (8%) with coronary artery stenosis >50% (p=0.0008). Stepwise regression analysis identified 4 independent predictors of RAS > or = 50%: CAD severity (p=0.014), serum creatinine concentration (p <0.001), cigarette smoking (p=0.02) and stenosis of aortic arch branches (p <0.001).

CONCLUSIONS

RAS is a frequent finding in patients with suspected CAD. CAD severity, number of involved aortic arch arteries, cigarette smoking and serum creatinine are independent RAS predictors.

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.

Selenium status indices, laboratory data, and selected biochemical parameters in end-stage renal disease patients

We investigated the relations between selenium status (SeS) parameters, indexes of nutrition, erythropoiesis, and uremic toxemia, serum electrolytes, and other biochemical markers in end-stage renal disease (ESRD) patients, as no multivariate statistical analysis concerning all of these parameters was performed so far. SeS was evaluated by plasma Se concentration (plSe) and glutathione peroxidase (plGSHPx) activity in 69 uremic patients treated with hemodialysis (HD) and 40 healthy controls. The hierarchical multivariate partial least squares model (PLS2) was employed to establish data structure and correlations between parameters investigated. plSe and plGSHPx activity were significantly lower in patients when compared with controls (p=0.000). plSe was positively associated with indexes of erythropoiesis and nutritional status, as well as serum electrolytes and parameters of uremic toxemia. plGSHPx was inversely dependent on the pair of parameters: intact parathyroid hormone (iPTH) and aluminum plasma concentration (Al). We conclude that (1) ESRD strongly decreases selenium status and (2) the PLS2 approach revealed the existence of significant interactions among plSe, plGSHPx, and selected biochemical parameters or groups of such parameters; some of these associations need further studies to be clarified.

Coronary artery calcification, common carotid artery intima-media thickness and aortic pulse wave velocity in patients on peritoneal dialysis

An increasing body of evidence suggests that atherosclerosis in patients with uremia differs from that found in general population in terms of advancement and localization of vascular lesions. It has also been suggested that different non-invasive techniques of vascular system evaluation are designed to show different types of lesions (i.e. vascular calcification, stiffness or 'classical' atherosclerosis). The aim of the study was to search for possible associations between results obtained with three different non-invasive methods of vascular system assessment in three different vascular sites in patients treated with peritoneal dialysis (PD). 61 patients (28 F, 33 M), mean age of 50.4+/-13.6 years, on maintenance PD for a median period of 10 months (range 1-96 months) were included. Coronary artery disease (CAD) was present in 21 subjects. In all subjects coronary artery calcification score (CaSc) using multi-row spiral computed tomography (MSCT), aortic pulse wave velocity (AoPWV) and ultrasound-based common carotid artery intima-media thickness (CCA-IMT) were performed as methods for assessing coronary calcium burden, arterial stiffness and atherosclerosis, respectively. Median value of CaSc equaled 11.5 Agatston units (range 0-5502.8 units). Median AoPWV was 10.4 m/s (range 7.56-18.1 m/s), and median CCA-IMT-0.6 mm (range 0.3-1.0 mm). In 16 patients (26.2%) at least one plaque in at least one common carotid artery was found on ultrasound. CaSc correlated with AoPWV (R=0.32, p<0.01) and with CCA-IMT (R=0.35, p<0.005), whereas no association was found between AoPWV and CCA-IMT. AoPWV, but not CaSc nor IMT correlated with blood pressure. The values of CCA-IMT and AoPWV increased together with consecutive Agatston categories (with p<0.001 for differences in AoPWV and p<0.05 for CCA-IMT). Patients with at least one plaque found in at least one CCA and patients with CAD were characterized with significantly higher values of CaSc, IMT and PWV, when compared to plaque-free and CAD- negative subjects, respectively. Association between CaSc and both IMT and PWV may suggest that the mechanism of three assessed vascular pathologies may be based, to some extent, on the process of pathologic calcium-phosphate deposition. Lack of correlation found between PWV and IMT may suggest that aortic stiffness and carotid atherosclerosis may partially differ in their pathologic background and/or are dissociated in time.

[Evaluation of polyneuropathy severity in chronic renal failure patients on continuous ambulatory peritoneal dialysis or on maintenance hemodialysis]

The aim of the study was to assess severity of injury of the peripheral nervous system of chronic renal failure patients on continuous ambulatory peritoneal dialysis (CAPD) or on maintenance hemodialysis (HD) diagnosed based on the electrophysiological testing as well as to establish the effect of adequate dialysis dose on peripheral nerve functioning. The study was performed in 53 patients (21 males, 32 females) on CAPD for mean 16.9 +/- 14.4 months and 68 patients (46 males, 22 females) on HD for mean 47.5 +/- 46.5 months. Both groups were age matched (48.9 +/- 12.4 vs. 50.6 +/- 11.9 yrs; p= NS). Patients with co-existing diseases that could lead to disturbances in nerve conduction were excluded from the study group.

METHODS

Electrophysiological testing was performed using Medelec Shaphire 2ME equipment. Nerve conductivity testing was performed in motor and sensory fibres of right ulnar nerve, motor fibres of right fibular nerve and left tibial nerve as well as in sensory fibres of right calf nerve. In the sensory nerves there were assessed: amplitude of the evoked sensory response, latency of the response and conduction velocity. In the motor nerves there were analyzed amplitude of the compound muscle action potential, latency of the evoked response, F-wave minimal latency and conduction velocity. Polyneuropathy was diagnosed if abnormal results obtained in electrophysiological examination were found in at least two out of four tested nerves. To assess dialysis adequacy in the CAPD group weekly Kt/V (wKt/ V) and weekly creatinine clearance (WCrCI) were used and in the HD patients the following indices were measured: Kt/V, PRU, TAC and TAD.

RESULTS

Polyneuropathy diagnosed based on the above described criteria, was found in 59 (86.8%) HD patients and in 41 (77.4%) CAPD patients (p= NS). The results of motor conductivity testing showed significantly longer distal latency in HD patients in comparison to the CAPD patients in fibular nerve (4.9 +/- 0.9 vs. 4.5 +/- 0.8 ms; p< 0.05) and F-wave latency in ulnar nerve (29.3 +/- 3.1 vs. 27.3 +/- 2.5 ms; p< 0.05), in fibular nerve (52.4 +/- 6.4 vs. 48.5 +/- 7.94 ms; p< 0.05), in tibial nerve (54.8 +/- 7.8 vs. 50.6 +/- 7.12 ms; p< 0.05) and also significantly lower conduction velocity in ulnar nerve (51.9 +/- 5.9 vs. 55.6 +/- 6.99 m/s; p< 0.05), in fibular nerve (41.2 +/- 5.9 vs. 44.5 +/- 5.5 m/s; p< 0.05), in tibial nerve (40.1 +/- 5.81 vs. 42.7 +/- 4.6 m/s; p< 0.05). Mean value of sensory response amplitude evoked in ulnar nerve was significantly higher in the CAPD treated patients than in HD patients (21.2 +/- 14.8 vs. 15.1 +/- 11.4 microV; p< 0.05) and distal latency in calf nerve was significantly shorter (2.1 +/- 1.0 vs. 2.4 +/- 0.6 ms; p< 0.05). Analysing the effect of dialysis on peripheral nerve functioning in the group of CAPD patients a statistically significant relationship between the severity of peripheral nerve injury and WCrCl was demonstrated. Mean value of WCrCl in patients without features of neuropathy was significantly higher (83.3 +/- 28.98 l/week/ 1.73m2) in comparison with those with diagnosed polyneuropathy (59.9 +/- 15.9 l/week/1.73m2) (p< 0.01). Analyzing effect of WCrCl on conduction velocity in the tested nerves there was demonstrated that in patients with WCrCl value at least 60 l/week/1.73m2, mean velocity values were higher, and the statistically significant difference was found for sensory (p< 0.05) and motor (p< 0.01) fibers of ulnar nerve. Mean value of residual renal clearance in the CAPD treated patients without features of sensory and motor nerve injury was significantly higher (2.9 +/- 1.8 ml/min) when compared to the patients with diagnosed polyneuropathy (1.4 +/- 1.3 ml/min) (p= 0.006). In the hemodialyzed group no statistically significant relationship was found between conduction velocity in the tested nerves and indices of dialysis efficiency (Kt/V, PRU) as well as degree of exposure to uremic toxemia described by TAC and TAD.

CONCLUSIONS

Polyneuropathy is a common complication in patients with chronic renal failure independently of a kind of the therapy. Well preserved residual renal function in CAPD patients plays an important role in improving effectiveness of the dialytic treatment, in consequence influencing preservation of proper peripheral nerve function.

The relationships between activation of non-specific inflammatory process and malnutrition in patients on peritoneal dialysis

Malnutrition is a frequent complication among patients on chronic peritoneal dialysis and early recognition of malnutrition can be a key factor in successful treatment. The aim of the study was to assess the nutritional status of patients on peritoneal dialysis and to search for the relationships between activation of non-specific inflammatory process and progression of malnutrition. The study group included 60 patients (age 50.4+/-14 years) on peritoneal dialysis for 17.6+/-20 months. Fourty-six patients completed the entire 24-month observation period. Nutritional status was assessed using SGA scale, anthropometric measures, bioimpendance, and several biochemical parameters. Inflammatory markers included: IL-6, TNFalpha, fibrinogen and CRP. Severe malnutrition was observed in the range between 8.4% (5 subjects, group C in SGA scale) to 11.7% (7 subjects, BMI <20 kg/m2) of patients. The nutritional status of the entire cohort was constant over 2 years of observation (based on SGA scale), although the mean albumin level decreased significantly after 24 months of observation (from 39.55+/-3.5 to 37.63+/-3.7 g/l; p<0.01). The mean concentrations of CRP (4.8 and 5.25 mg/l), IL-6 (3.45 and 6.8 pg/ml) and leptin (22.95 and 22.2 ng/ml) were above reference ranges both at the initial and final assessment. Moreover, the concentration of IL-6 significantly increased (p<0.001) after 24 months of observation. Patients treated with PD are frequently affected by malnutrition. Our results indicate a strong association between nutritional indices and markers of inflammation.

Does coronary artery calcification in patients with diabetic nephropathy depend on the advancement of renal failure?

Calcium-phosphate disorders and vascular calcification are highly prevalent in patients with diabetes mellitus and nephropathy. The aim of the study was to compare the prevalence and advancement of vascular calcification in patients with end-stage diabetic nephropathy on peritoneal dialysis and diabetic patients with chronic renal disease stages 2-4. The study group included 31 patients with type 2 diabetes and diabetic nephropathy divided into 2 groups: 12 patients (aged 50-74 years: mean 58.6+/-8.8) undergoing peritoneal dialysis and 19 patients (aged 46-82 years; mean 65.8+/-9.7) with chronic kidney disease stages 2-4 (GFR range 24-78 ml/min/1.73 m2). Coronary artery calcification score, was assessed using multi-slice computed tomography. Coronary artery calcification score did not differ significantly between groups (CaSc values 1085.2 vs 452.4 AgU; NS). The patients undergoing peritoneal dialysis showed significantly higher levels of parathyroid hormone (658.2 vs. 74.3 pg/ml; p=0.001), fibrinogen (5.82 vs. 3.89 g/l; p<0.0001) and alkaline phosphatase (330.9 vs. 168.0 U/l; p=0.001). Despite more advanced abnormalities in calcium-phosphate balance parameters and more active inflammation in peritoneal dialysis subjects we failed to demonstrate any statistically significant difference in coronary artery calcification score between patients with diabetic nephropathy on peritoneal dialysis and those with chronic kidney disease stages 2-4.

[Nephropathies of adolescence--the issue for the pediatrician and the internist]

Apart from the kidney diseases typical for early childhood, which (at least when clinically active) are entirely covered by pediatricians, there are several other nephropathies which occur predominantly in the period of adolescence and may be of potential interest for internist. In this review some clinical and therapeutic aspects of certain nephropathies of adolescence were discussed, namely lupus nephritis, Henoch-Schoenlein purpura nephritis, and the renal involvement in small vessel vasculitis. Medical and psychological problems that may arise not only from the presence of chronic disease, but also from the treatment side effects and difficulties in transition from pediatrician to internist were emphasized. Finally, certain circumstances and standards of smooth and comfortable transition of adolescent patient from pediatric to 'adult' nephrologist were proposed.

[Analysis of selected inflammatory markers in patients with stable renal graft (RTx) 36 months after transplantation]

Chronic inflammation is an inherent feature of chronic renal failure. Successful renal transplantation (RTx) is the only known renal replacement therapy sufficient to reverse most of the metabolic disturbances of chronic uremia, although still some of these abnormalities may be present or even new problems may occur (mostly as the side effects of immunosuppressive drugs). The aim of this study was to evaluate the level of inflammation in 20 patients (9 F, 11 M, aged mean 44.0 +/- 11.8 years) with well-preserved renal function 36 months after kidney transplantation, using serum levels of selected cytokines (IL-6, IL-18, TNFalpha and soluble receptor for TNF - sTNFRII), acute phase proteins (CRP, fetuin A) and hepatocyte growth factor (HGF). Procalcitonin was also assessed as the sensitive indicator of active infection. Obtained results were compared with the control group of healthy subjects in a respective age. Serum levels of IL-6, TNF-R and IL-18 were significantly higher, and HGF and fetuin A--significantly lower in patients vs. controls (p < 0.05 for all differences). Significant negative correlations were noted between glomerular filtration rate (GFR) and serum TNF, sTNFRII and IL-18 in RTx patients, whereas strong positive relationship between GFR and fetuin A was observed. Serum creatinine correlated with IL-6, IL-18, TNFalpha, sTNFRII and hsCRP levels and serum urea-with TNFalpha, sTNFRII, IL-6 and IL-18. Significant negative associations were also noticed between serum fetuin A and most of the tested inflammatory markers: sTNFRII (r = -0.77; p = 0.0005), IL-6 (r = -0.63; p = 0.009), hsCRP (r = -0.62; p = 0.009) and IL-18 (r = -0.60; p = 0.01). Obtained results permit us to conclude that the increased activity of inflammation can still be noticed in RTx patients 36 months after successful engraftment. This process is inversely associated with the level of kidney function. The role of fetuin A as the 'negative' acute phase protein was also demonstrated in this group of patients.

Pure red cell aplasia due to treatment with epoietin beta: first case report of PRCA from Poland

Pure red cell aplasia (PRCA) emerged recently as the potentially life-threatening condition secondary to anti-Epo antibodies. Vast majority of cases were reported from Western European countries and were secondary to subcutaneous injections of Epoietin alpha. Here we describe possibly for the first time in the literature the case of PRCA from Poland or even Central and Eastern Europe in patient treated exclusively with Epoietin beta from multi-dose vial. In the last section of the paper the current epidemiological, diagnostic and therapeutic aspect of PRCA were discussed.

[Ethical and legal issues concerning renal replacement therapy withdrawal or withholding]

Rapid and dynamic increase of the number of patients that need different forms of renal replacement therapy can be noticed in the developed countries. This increase is associated with increased number of patients with 'diseases of modern civilization', such as diabetes and hypertension, which lead to kidney complications (e.g. diabetic and hypertensive nephropathy). Improved long-term care (especially diabetic and cardiologic) allows these patients to survive longer and to reach the stage of end-stage renal disease. This leads to increasing age and morbidity of patients treated with dialysis. In many cases, due to extremely advanced level of co-morbidity patients on dialysis are exposed to extreme level of suffering and unacceptably low quality of life. Persistent continuing of renal replacement therapy under such circumstances (with no hope for recovery or improvement) raises also some economical issues, especially in the context of permanent crisis and shortage of resources in health systems of most countries in the world. In this review the current practice concerning withdrawal or withholding of renal replacement therapy as well as some legal and ethical issues of this practice are discussed.

Changes in common carotid artery intima-media thickness over 1 year in patients on peritoneal dialysis

BACKGROUND

Accelerated atherosclerosis and vascular calcifications increase cardiovascular morbidity and mortality in patients on dialysis. Common carotid artery (CCA) intima-media thickness (IMT) is considered useful for imaging atherosclerosis non-invasively. Since chronic inflammation may accelerate atherosclerosis in end-stage renal disease patients, the aim of this 1 year study was to assess changes in CCA-IMT in stable peritoneal dialysis (PD) patients, and to search for possible associations between these changes and selected cytokines, acute phase proteins and other risk factors of atherosclerosis.

METHODS

Of the original cohort of 61 stable patients on PD-28 female, 33 male; mean age 50.4+/-13.6 years; dialyse for a median of 17.5 months at inclusion (range 1-96 months)-47 patients survived the 1 year period on PD. CCA-IMT was assessed at baseline and after 12 months. Pro-inflammatory cytokines (IL-6, TNFalpha), acute phase proteins (CRP, fibrinogen), calcium-phosphate balance and lipid profile were assessed at baseline and after 6 and 12 months. Anthropometric parameters (age, weight, BMI, waist-to-hip ratio) were measured at baseline.

RESULTS

The mean CCA-IMT at baseline, 0.66+/- 0.19 mm, increased by a mean of 0.098+/-0.17 to 0.76+/-0.21 mm (P<0.001) in 1 year. In 14 patients (29.8%) at least one plaque was found in the CCAs examined. At the end of follow-up: 28 patients (59.6%) had increases in CCA-IMT (from 0.63+/-0.2 to 0.83+/- 0.21 mm; P = 0.03), and 19 (40.4%) remained stable or even showed slight, but non-significant, decreases of CCA-IMT (from 0.72+/-0.17 to 0.66+/-0.17 mm, P = NS). The 'progressors' had significantly higher initial BMI (P<0.05), and mean concentrations of calcium (P = 0.005), IL-6 (P = 0.05), TNFalpha (P = 0.05), CRP (P = 0.005) and lower HDL-cholesterol than 'non-progressors'. In univariate analysis, DeltaCCA-IMT correlated positively with age (R = 0.32, P = 0.03), BMI (R = 0.29, P = 0.05) and mean concentrations of CRP (R = 0.37, P = 0.01), TNFalpha (0.52, P = 0.0002), but inversely with HDL-cholesterol (R = -0.37, P = 0.01). In multiple regression analysis, however, only age appeared to be independently associated with increase in CCA-IMT (beta = 0.37, P<0.01; R(2) for the model 0.14).

CONCLUSIONS

Our results suggest a possible role of non-specific inflammation in the progression of atherosclerosis in patients treated with PD, in addition to age.

Peritoneal dialysis with solutions low in glucose degradation products is associated with improved biocompatibility profile towards peritoneal mesothelial cells

BACKGROUND

In vitro experiments point to a better biocompatibility profile of new pH-neutral peritoneal dialysis fluids (PDFs) containing low levels of glucose degradation products (GDPs). The present study examines the impact on human peritoneal mesothelial cells (HPMCs) of equilibrated dialysates obtained during dialysis with either conventional or new PDFs.

METHODS

Peritoneal dialysate was collected from 17 patients participating in a randomized, controlled, cross-over trial comparing a pH-neutral low-GDP solution (Balance) to a conventional solution (S-PDF). All patients were treated sequentially for 3 months with both PDFs. At the end of each treatment phase, peritoneal effluent was drained after a timed 10 h dwell. Samples of dialysate were then mixed with standard culture medium and added to in vitro cultures of HPMCs from healthy donors. Cells were assessed for proliferation, viability and cytokine release.

RESULTS

Proliferation and viability of HPMCs were better preserved in the presence of effluent obtained during dialysis with Balance (P<0.046 and P<0.035, respectively). The proliferative response of HPMCs correlated with the concentration of fibronectin in dialysates (P = 0.0024). Effluent drained following a 3 month dialysis with Balance contained significantly increased levels of fibronectin (P = 0.004) and CA125 antigen (P = 0.0004) compared with S-PDF. There was no significant difference in constitutive and stimulated cytokine (IL-6, MCP-1, VEGF) synthesis by HPMCs treated with either Balance- or S-PDF-derived effluents.

CONCLUSIONS

These results suggest that therapy with new pH-neutral low-GDP solutions contribute to an intraperitoneal milieu that improves mesothelial cell proliferation and viability. It may positively impact on the preservation of the peritoneal membrane integrity during long-term dialysis.

Application of LDL-apheresis and immunoadsorption in kidney diseases

Plasmapheresis is one of the methods of extracorporeal blood purification used for many decades for the treatment of different kidney and extrarenal diseases, mainly of autoimmunological nature. The main disadvantage of this method is the lack of selectivity and the risk of infections associated with plasma used for supplementation. Hence, the efforts are made to establish an alternative blood purification treatment that might be used in renal diseases instead of plasmapheresis. These alternative methods should be more selective in certain pathogenic factors elimination and result in less risk for patient, both acute and delayed. Recently two such methods were applied more frequently to everyday nephrological practice, i.e. LDL-apheresis and immunoadsorption. The present paper aims to review the current state of knowledge regarding use of two mentioned methods in kidney diseases. Despite their very high costs both of them if used early in certain, refractory nephropathies may ameliorate their clinical course and significantly improve the prognosis. In addition they may significantly reduce the overall costs of therapy due to avoidance of unnecessary immunosuppression, prolonged hospitalization and finally--costs of postponed renal replacement therapy.

Evaluation of gastric emptying in patients with chronic renal failure on continuous ambulatory peritoneal dialysis using 99mTc-solid meal

BACKGROUND

Continuous ambulatory peritoneal dialysis (CAPD) is an alternative to the hemodialysis mode of terminal renal failure treatment. Nutritional status impairment is common among patients with end-stage renal disease, and its laboratory surrogates predict increased morbidity and mortality risk in patients on chronic haemodialysis or peritoneal dialyses. The aetiology of malnutrition is multifactorial and delayed gastric emptying is also considered to be a significant factor. The aim of this study was to estimate the direct influence of indwelled dialysate in the peritoneal cavity on gastric emptying in patients treated with CAPD.

MATERIAL AND METHODS

the study group included 20 patients (9 males, 11 females) aged 50,1 +/- 11 years (range: 39-75 years) with chronic renal failure treated with CAPD for 18.4 +/- 14.7 months. All patients were non-diabetic and had no other than chronic uraemia co-morbidity known to influence autonomic nervous system function and gastric motility. The control group included 15 healthy volunteers matched by age, sex and body weight. Dialysis adequacy parameters were calculated based on 24-hour urine and dialysate collections. Gastric emptying was estimated with dynamic abdominal scintigraphy. We compared the results of gastric emptying tests performed in dialysed patients with and without dialysate liquid in the peritoneal cavity and related the values to those of the control subjects.

RESULTS

In the study group, weekly values of dialysis parameters were within the ranges considered satisfactory in terms of uraemia control. All parameters of gastric emptying were significantly delayed and prolonged in terminal renal failure patients, but the results have shown no significant differences between those with and without indwelling dialysate.

CONCLUSIONS

Based on the results we conclude that gastric emptying in subjects with chronic renal failure treated with CAPD is markedly delayed compared to healthy subjects. There was no significant effect of indwelling dialysate in the peritoneal cavity on gastric emptying rates found, based on the observation that its removal was not associated with any noticeable improvement of gastric emptying. The data strongly contraindicate the theory of peritoneal dialysate volume being the cause of this reversible disorder and indicate that the role of other possible factors leading to the development of gastropathy in those patients should be investigated.

Dialysis adequacy, residual renal function and serum concentrations of selected low molecular weight proteins in patients undergoing continuous ambulatory peritoneal dialysis

BACKGROUND

Low molecular weight proteins (LMWP) are considered uremic toxins. There is controversy whether in peritoneal dialysis (PD) the elimination of these toxins is influenced mainly by dialysis or by residual renal function (RRF).

MATERIAL/METHODS

The aim of our study was to evaluate the relationship between serum levels of selected LMWPs, dialysis adequacy, and RRF in PD patients. 27 stable subjects were studied, mean age 50+/-11, dialyzed for a median period of 10 months. Serum activity of acid RNA-se and alkaline RNA-se was measured by spectrophotometry, and serum alpha1-microglobulin ((alpha) 1M) concentration by ELISA. Kt/V and weekly creatinine clearance (wClCr) were assessed as adequacy indices (both as the sum of renal and dialysis components) and RRF as the mean of residual urea and creatinine clearances.

RESULTS

Significant inverse correlations were found between RRF and (alpha) 1M level, as well as alkaline RNA-se activity (p<0.0001). A similar relationship was found for residual Kt/V (p<0.0001 for (alpha) 1M and alkaline RNA-se). There was no significant correlation between acid RNA-se activity and any tested parameter of adequacy. When the cutoff points of wClCr = 60 L/week/m2, total Kt/V = 2.0, or RRF=2.0 ml/min were used, we found (alpha)1M level and alkaline RNA-se activity to be significantly lower in patients with higher values of the

CONCLUSIONS

RRF plays an important role in elimination of LMWP in PD. The activity of alkaline RNA-se and acid RNA-se behaves differently in these patients.

LDL-apheresis and immunoadsorption: novel methods in the treatment of renal diseases refractory to conventional therapy

Plasma exchange was used for many years as the method of extracorporeal removal of antibodies and/or immune complexes that may be involved in the pathogenesis of renal diseases. Recently low-density lipoprotein (LDL)-apheresis and immunoadsorption were also introduced into nephrological practice. LDL-apheresis, designed originally as a rescue treatment for refractory hyperlipidaemia, appeared also to be effective in certain glomerulopathies, resistant to other treatment strategies. Similarly, immunoadsorption can be employed successfully in the treatment of different nephropathies, of both immunological and non-immunological pathogenesis. This method may also be effective as rescue treatment in some cases of acute rejection and recurrence of certain nephropathies after renal transplantation. The major advantage of both methods is their increased selectivity compared with standard plasma exchange. In addition, these techniques need no supplement fluid (namely fresh frozen plasma), which allows for markedly increased efficacy of the treatment as well as substantial reduction of infection risks.

An association between aortic pulse wave velocity, blood pressure and chronic inflammation in ESRD patients on peritoneal dialysis

Increased aortic pulse wave velocity (AoPWV) has been identified as a risk factor for cardiovascular morbidity in the general population and in patients on dialysis. Most of the studies in ESRD patients refer to subjects on hemodialysis. Influence of the inflammatory process on aortic stiffening remains largely unknown. The aim of the present study was to evaluate potential relationships between AoPWV and blood pressure, basic anthropometric parameters, selected growth factors and markers of the inflammatory process in ESRD patients treated with peritoneal dialysis. The study population consisted of 43 patients (19 F, 24 M) with a mean age of 50.6 +/- 13.4 years on PD for a mean period of 21.9 +/- 20.7 months. AoPWV was measured using two pressure transducers placed on the carotid and femoral arteries and connected to an automatic processor (Complion Colson AS, Paris, France). Serum levels of Tumor Necrosis Factor alpha (TNFalpha), interleukin 6 (IL-6) and plasma basic Fibroblast Growth Factor (bFGF) were measured with ELISA; C-reactive protein and fibrinogen with nephelometry. Serum lipid profile was also assessed. Blood pressure was measured in an outpatient department under standardized conditions. Mean aortic pulse wave velocity in the study population was 10.7 +/- 2.1 m/s. No difference in AoPWV was found between men and women. AoPWV correlated significantly with age (R = 0.41; p < 0.01) but not with time on dialysis. Positive relationship between AoPWV and body weight and BMI was shown (R = 0.31; p < 0.05 and R = 0.35; p < 0.05, respectively). AoPWV correlated significantly with systolic blood pressure (SBP), mean arterial pressure (MAP) and pulse pressure (PP) (R = 0.46, p < 0.005, R = 0.46, p < 0.005 and R = 0.43, p < 0.01, respectively). AoPWV correlated with serum IL-6 and plasma bFGF (R = 0.32, p < 0.05 and R = 0.4, p < 0.01; respectively). The correlation with serum CRP was borderline significant (p < 0.53). In multiple regression analysis age (beta 0.38; p < 0.005), plasma bFGF level (beta 0.3; p < 0.05), and systolic blood pressure (beta 0.29; p < 0.05) were independently associated with pulse wave velocity. Our results suggest that AoPWV values in patients on PD are associated with factors similar to those encountered in the general population. We suggest that increased aortic stiffening may also be related to the chronic inflammatory process in PD patients.

An association between coronary artery calcification score, lipid profile, and selected markers of chronic inflammation in ESRD patients treated with peritoneal dialysis

BACKGROUND

Chronic uremia is considered a proinflammatory state associated with high cardiovascular morbidity and mortality. The aim of the present study is to evaluate the potential relationship between the prevalence of coronary artery calcification (CAC) and selected factors that may be involved in the process of atherogenesis (lipid profile, acute-phase reactants, growth factors, and cytokines).

METHODS

The study group consisted of 43 patients (19 women, 24 men) with a mean age of 50.6 +/- 13.4 years treated with peritoneal dialysis (PD) for a median period of 15 months (range, 2 to 96 months). Only patients with sinus rhythm were included. CAC score (CaSc) was measured using multirow spiral computed tomography (MSCT). As parameters of lipid profile, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides were assayed. C-reactive protein (CRP) and fibrinogen represented the level of acute-phase activation. Proinflammatory cytokines (interleukin-6 [IL-6] and tumor necrosis factor-alpha [TNF-alpha]), leptin, and basic fibroblast growth factor (bFGF) also were measured.

RESULTS

Median CaSc equaled 17.9 Agatston units (range, 0 to 5,502 Agatston units). No calcification was detected in 20 subjects (46.5%; CaSc < 10 Agatston units). CaSc correlated with age (R = 0.57; P < 0.0001), body mass index (R = 0.42; P < 0.005), and serum leptin (R = 0.3; P < 0.05) and CRP levels (R = 0.38; P < 0.05). The correlation with PD therapy duration was borderline statistically significant (P = 0.063). Patients with the greatest values for CaSc (> 400 Agatston units) were characterized by significantly greater levels of IL-6, bFGF, and CRP compared with subjects with a CaSc less than 10 Agatston units (P < 0.05 for all). Patients with history of coronary artery disease (CAD) had significantly greater CaSc values (median, 778.6 versus 3.3 Agatston units; P < 0.001) compared with those without CAD. Serum triglyceride levels were significantly greater and HDL cholesterol levels were significantly lower in patients with CAD. The first group also was characterized by significantly greater serum TNF-alpha (P < 0.01) and CRP levels (P < 0.005). In multiple regression analysis, only age was independently associated with CaSc (beta = 0.45; P = 0.002).

CONCLUSION

Our results may suggest an association between CAC and chronic inflammation activity in the mentioned group of patients. To our knowledge, this is the first study reporting the prevalence of CAC in PD patients using the MSCT method. The association between CaSc results and classic, as well as inflammatory, risk factors for CAD found in this study should be interpreted with caution because of its method limitations (cross-sectional design, heterogeneity of study population, and small number of studied patients).