Leukocyte Adhesion Molecules and Leukocyte-Platelet Interactions during Hemodialysis: Effects of Different Synthetic Membranes

Membranes made from synthetic polymers, in general, are considered as being biocompatible membranes and tend to be treated as a homogeneous group. However, all of these membranes have multiple and different characteristics that may contribute to interactions with blood components. As a consequence, the biocompatibility profile of synthetic membranes may vary. In the present cross-over study, we examined by flow cytometry the effects (expressed as % change from predialysis values) of three different synthetic polymers (polysulfone, PSF; polyacrylonitrile-co-sodium methallyl sulfonate, AN69; ethylenevinylalcohol, EVAL) on the expression of leukocyte adhesion molecules (CD11b/CD18, CD15s) and the interactions between leukocytes and platelets under conditions of routine clinical use.

For neutrophils, a statistically significant difference was found in CD15s expression for EVAL as compared to AN69 (p<0.05) and in CD11b/CD18 expression for PSF as compared to both EVAL (p<0.01) and AN69 (p<0.05). No difference between membranes was found on the expression of such adhesive molecules on monocytes. Significant differences in platelet-neutrophil (but not in platelet-monocyte) coaggregate formation were observed between PSF and both EVAL (p<0.001) and AN69 (p<0.01). Reactive oxygen species production by neutrophil population during hemodialysis was significantly different between each pair of synthetic polymers (PSF vs EVAL, p<0.001; PSF vs AN69, p<0.001; AN69 vs EVAL, p<0.05).

Our data demonstrate that in terms of leukocyte adhesion receptors and platelet-leukocyte interactions, the biocompatibility profile of the synthetic membranes polysulphone, AN69 and EVAL shows many similarities but also several significant differences. Our results support the concept that biocompatibility evaluation of each membrane should be based exclusively on data generated by that membrane in order to avoid errors based on assumptions about group characteristics.

A New Polymethylmethacrylate Membrane for Hemodialysis

High molecular weight (MW) solutes are not removed during conventional hemodialysis (HD), and their accumulation is thought to play a role in some long-term HD complications (anemia, bone and joint pain, neuropathy, itching). The present trial was conducted to evaluate the removal capacity during in vivo HD of a new polymethylmethacrylate (PMMA) membrane (Filtryzer BK-F, 1.3 m2) compared to conventional PMMA (BK-P, 1.6 m2) and to cellulose acetate (CA, 1.3 m2). BK-F dialyzers, with a pore size of 100 A° and 62% porosity, are designed to remove high MW substances. Ten stable anuric RDT patients (53 ± 13 years) were treated for one week with each membrane in a randomized sequence. Plasma concentrations of creatinine, BUN and beta2-microglobulin (beta2-M) were measured before (b) and after (a) HD to determine the reduction rate for these substances (%). Beta2-M concentration after HD was corrected for changes in distribution volume. Samples of spent dialysate were collected after 3 minutes, 120 minutes and at the end of HD sessions, and appropriately treated and concentrated for HPLC analysis. The reduction rate for BUN and creatinine was similar for the 3 membranes. BK-F showed a higher beta2-M reduction rate than BK-P (p<0.005) or CA (p<0.0001). HPLC analysis of dialysate showed prevalent peaks < 4 kilodaltons (kDa) throughout HD for BK-P and CA. Solutes > 10 kDa were infrequently detected. Peak profile during HD with BK-F was quite different, showing a predominant peak > 50 kDa which also included albumin. However, albumin loss significantly decreased after 120 minutes and at the end of dialysis compared with the 3-minute values, and was lower than that reported in CAPD patients. With BK-F a peak of MW > 500 kDa was also detected which previous studies indicated as a range characterized by the presence of erythropoiesis inhibitors. Use of the BK-F membrane in HD could afford satisfactory removal of high MW substances, thereby preventing or controlling some long-term HD complications such as anemia or beta2-M amyloid formation.

Clinical Evaluation of Internal Hemodiafiltration (iHDF): A Diffusive-Convective Technique Performed with Internal Filtration Enhanced High-Flux Dialyzers

Aim

Efficiency in removing middle molecules such as ß2-microglobulin (ß2-MG) is one of the main purposes of modern dialytic therapy. In order to achieve this, techniques requiring complex machines and substitution fluid have been developed over recent years. Alternatively, the internal filtration / back filtration phenomenon can be used. The recent development of a so-called “internal filtration enhanced dialyser” prompted us to compare the removal of ß2-MG together with other small molecules when the dialyser was used either in standard hemodiafiltration (HDF) or internal hemodiafiltration (iHDF).

Methods

Ten stable, anuric, hemodialysis (HD) patients treated by thrice weekly standard bicarbonate HD using low-flux synthetic membrane entered the study. A new high-flux polysulfone dialyser designed with the specific aim of enhancing internal filtration (BS-1.6 UL, 1.6 m2, Toray Industries) was used. Post dilution HDF (2.5 l/hour of substitution fluid, dialysate flow 500 ml/min) was compared with iHDF (dialysate flow 750 ml/min), with blood flow at 300 ml/min. Samples were obtained at the start and at the end of the session in order to measure the % removal of urea, creatinine, uric acid, phosphate and ß2-MG (corrected for total protein concentration). In addition, after 20 min of dialysis the clearances of the same molecules were measured. A mathematical model has been developed for the description of the hydrodynamic phenomena taking place within the dialyser and of fluid filtration across the membrane.

Results

No significant differences have been observed in removal rate switching from HDF to iHDF except for ß2-MG removal, which was slightly higher in HDF than in iHDF. Phosphate clearance is significantly higher than those obtained with creatinine in both HDF (p<0.005) and iHDF (p<0.01) modalities. The total convection calculated with the model is reduced with respect to HDF only by 24% (4100 ml/h vs. 5400 ml/h on the average).

Conclusions

iHDF is a high flux dialysis method, which, if performed with a dialyser designed to enhance internal filtration, obtains a much higher removal rate in comparison with dialysers in traditional high flux dialysis, as previously reported in the literature. Provided that the dialyser is used on a dialysis machine working with ultra pure dialysate and UF control, this dialyser line can perform reliable internal HDF without the need for replacement solution. Considering the narrow difference in performance observed between iHDF and HDF, and the increasing number (and age) of patients leading to higher dialysis costs, iHDF represents a cost-effective alternative to other diffusive-convective techniques.

The natural history of uremic neuropathy

The results obtained by electrophysiological recording allow to discover the constant presence of alterations to the central and/or peripheral nervous system in the uremic syndrome. Thus, it becomes possible to demonstrate the existence of an actual 'uremic neuropathy'. Moreover, the results show the persistence and progression of uremic involvement in the course of dialytic treatment; only after kidney transplantation a return to normal takes place. Methodological and interpretative progress will allow us in the future to broaden our knowledge of uremia by providing a useful guide to therapeutic strategies.

Multicentric experience with combined hemodialysis/hemoperfusion in chronic uremia

A multicentric study was carried out to investigate the safety and effectiveness of long-term treatment of chronic uremic patients by a regular combination of hemodialysis and charcoal hemoperfusion. 39 RDT patients from five dialysis centers were treated for up to 12 months. The combined treatment proved to be safe, well tolerated and effective in improving certain dialysis-resistant uremic signs, mainly severe peripheral neuropathy, asthenia, anorexia, nausea, lack of well-being and relapsing pericarditis. There was also a marked decrease, after several weeks of combined treatment, in plasma values of urea, uric acid and creatinine.

The Kidney Donor Profile Index (KDPI) of marginal donors allocated by standardized pretransplant donor biopsy assessment: distribution and association with graft outcomes

Pretransplant donor biopsy (PTDB)-based marginal donor allocation systems to single or dual renal transplantation could increase the use of organs with Kidney Donor Profile Index (KDPI) in the highest range (e.g. >80 or >90), whose discard rate approximates 50% in the United States. To test this hypothesis, we retrospectively calculated the KDPI and analyzed the outcomes of 442 marginal kidney transplants (340 single transplants: 278 with a PTDB Remuzzi score<4 [median KDPI: 87; interquartile range (IQR): 78-94] and 62 with a score=4 [median KDPI: 87; IQR: 76-93]; 102 dual transplants [median KDPI: 93; IQR: 86-96]) and 248 single standard transplant controls (median KDPI: 36; IQR: 18-51). PTDB-based allocation of marginal grafts led to a limited discard rate of 15% for kidneys with KDPI of 80-90 and of 37% for kidneys with a KDPI of 91-100. Although 1-year estimated GFRs were significantly lower in recipients of marginal kidneys (-9.3, -17.9 and -18.8 mL/min, for dual transplants, single kidneys with PTDB score<4 and =4, respectively; p<0.001), graft survival (median follow-up 3.3 years) was similar between marginal and standard kidney transplants (hazard ratio: 1.20 [95% confidence interval: 0.80-1.79; p=0.38]). In conclusion, PTDB-based allocation allows the safe transplantation of kidneys with KDPI in the highest range that may otherwise be discarded.

Natural radioactivity in refractory manufacturing plants and exposure of workers to ionising radiation

This paper shows the results of a survey carried out at some refractory manufacturing plants. During the first part of the survey, the concentration of natural radioactivity in raw materials and end-products, coming from four plants, was assessed. Several raw materials and, as a consequence, some end-products as well have shown activity concentrations exceeding a few hundreds of Bq kg(-1) of (238)U and (232)Th. In some important raw materials, such as bauxite and corundums, a remarkable radioactive disequilibrium was observed; this is probably due to the high temperature processes undergone by these materials. The second part of the survey focussed on the measurements of ambient equivalent dose rates, airborne dust concentrations and radon indoor. On the basis of results obtained, the effective dose for the standard worker was estimated. Two different types of refractory plants were investigated. Effective doses for both plants were lower than 1 mSv y(-1).

Pancreas transplantation inside Emilia-Romagna, Italy: referral pattern, demand forecasting, and organ availability

In Italy, referral of diabetic patients for pancreas transplantation (PT) is an unstructured process, resulting in a low rate of activity and late referrals, often when the patient has already undergone dialysis. In addition, the continuous improvement in pancreas transplant alone, offering the opportunity to reduce cardiovascular risk due to proteinuria and reduced glomerular filtration rate (GFR), is rarely appreciated. We therefore analyzed (1) referral activity to PT during the time frame 2001-2005 in Emilia-Romagna, Italy (four million inhabitants), by collecting ICD 9 CM codes (55.69 + 52.80; 52.86 and 52.80 alone) by residence of the patient; (2) demand for PT among a sample population of 1670 diabetes patients, whose charts were reviewed for the type of diabetes and presence of overt diabetic nephropathy (DN: proteinuria >300 mg/24 h and/or GFR <60 mL/min); (3) potential pancreas availability as the ratio between pancreas and hearts utilized (UP/HR) in different areas of our country. As a results, (1) referral activity reached 8.4 PT per million people in 5 years in the whole region, ranging from 2.6 in the province where a PT program is active, to a maximum value of 20.7 in the province where a devoted outpatient clinic is operated by nephrologists. (2) Prevalence of overt DN was 6% in our cohort, corresponding to 510 D1 patients worthy of evaluation for PT inside Emilia-Romagna region. (3) During 2006, UP/HR was 0.58 in Associazione Inter-Regionale Trapianti agency, 1.16 in Tuscany, 0.30 in Piedmont, and 0.26 in our region. Taken together, our data showed that (1) the referral of D1 to PT has to be empowered, keeping in touch with all patients suffering from diabetic nephropathy; (2) the outpatient clinic devoted to evaluation and recruitment of D1 with nephropathy plays the key role in this program of timely and widespread referral; (3) the availability of pancreata can be increased by utilizing broader criteria for harvesting, increased consent rate to donation and increased the demand for PT (recipient pool). Pancreas grafts need to increase, since the current low demand produces underutilization of the pancreas resource, due to the frequent lack of a suitable recipient.

[Autosomal dominant polycystic kidney disease: from genes to cilium]

Autosomal dominant polycystic kidney disease (ADPKD) is a quite frequent monogenic hereditary disease. The incidence has been reported to range between 1:400 and 1:1000 life births. The disease is caused by a mutation of the PKD1 gene in 85% of the cases and by a mutation of the PKD2 gene in the remaining 15%. The main characteristic of this condition is the development of renal cysts. Observations regarding various cystic kidney diseases sustained by mutations of different genes are steadily converging to a common point. This unifying element is the primary cilium. The cilium, which has long been considered a mere biological oddity, has lately become the focus of intense scientific attention because it may turn out to be the key to the understanding of cystic degeneration. The cilia can be regarded as sensors projecting out of the cell. In particular in the kidney they are located in an ideal place to capture information from the tubular lumen. One of the roles the cilia may play is the reception of chemical signals. An alternative hypothesis attributes to the cilia the role of mechanosensors capable of detecting variations of the urine flux in the tubular lumen. The cilium projects itself into the lumen where it can readily capture variations in the external environment and transmit them to the cell by as yet undefined pathways. This is the still largely unexplored frontier that will provide the elements needed to understand and treat renal cystic diseases.

[Dyslipidemia and the risk of kidney disease]

An abnormal lipid profile is very frequent in patients with kidney disease due to the well-known nephrotoxicity of lipids. During progression of chronic kidney disease, the excretion of triglycerides, LDL and proteins increases while the glomerular filtration rate declines. Blood lipoproteins and lipids are modulated depending on the type of treatment: hemodialysis, CAPD or renal transplant. We analyzed many studies on dyslipidemia in patients with kidney disease by comparing different therapies. The use of statins reduces protein excretion and hyperlipidemia as well as progression of chronic renal failure with a direct effect on mesangial cell proliferation. A decrease in total cholesterol and LDL occurs in hemodialysis patients, a decrease in LDL and an increase in HDL occur in CAPD patients, and a decrease in LDL and triglycerides is observed in renal transplant recipients; in the latter, graft survival increases without there being any relevant correlation with immunosuppressive treatment. In conclusion, we found that statins are useful to contrast the progression of chronic kidney disease and atherosclerosis in hemodialysis and CAPD patients and to reduce chronic allograft nephropathy in renal transplant recipients.

Accuracy of eight-polar bioelectrical impedance analysis for the assessment of total and appendicular body composition in peritoneal dialysis patients

OBJECTIVE

To establish the accuracy of bioelectrical impedance analysis (BIA) for the assessment of total and appendicular body composition in peritoneal dialysis (PD) patients.

DESIGN

Cross-sectional study.

SETTING

University Nephrology Clinic.

SUBJECTS

In all, 20 PD patients and 77 healthy controls matched for gender, age and body mass index.

METHODS

Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by dual-energy X-ray absorptiometry. Resistance (R) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz. Whole-body resistance was calculated as the sum of R of arms, trunk and legs. The resistance index (RI) was calculated as the ratio between squared height and whole-body or segmental R.

RESULTS

RI at 500 kHz was the best predictor of FFM, LTM(arm) and LTM(leg) in both PD patients and controls. Equations developed on controls overestimated FFM and LTM(arm) and underestimated LTM(leg) when applied to PD patients. Specific equations were thus developed for PD patients. Using these equations, the percent root mean-squared errors of the estimate for PD patients vs controls were 5 vs 6% for FFM, 8 vs 8% for LTM(arm) and 7 vs 8% for LTM(leg).

CONCLUSION

Eight-polar BIA offers accurate estimates of total and appendicular body composition in PD patients, provided that population-specific equations are used.

Accuracy of eight-polar bioelectrical impedance analysis for the assessment of total and appendicular body composition in peritoneal dialysis patients

OBJECTIVE

To establish the accuracy of bioelectrical impedance analysis (BIA) for the assessment of total and appendicular body composition in peritoneal dialysis (PD) patients.

DESIGN

Cross-sectional study.

SETTING

University Nephrology Clinic.

SUBJECTS

In all, 20 PD patients and 77 healthy controls matched for gender, age and body mass index.

METHODS

Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by dual-energy X-ray absorptiometry. Resistance (R) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz. Whole-body resistance was calculated as the sum of R of arms, trunk and legs. The resistance index (RI) was calculated as the ratio between squared height and whole-body or segmental R.

RESULTS

RI at 500 kHz was the best predictor of FFM, LTM(arm) and LTM(leg) in both PD patients and controls. Equations developed on controls overestimated FFM and LTM(arm) and underestimated LTM(leg) when applied to PD patients. Specific equations were thus developed for PD patients. Using these equations, the percent root mean-squared errors of the estimate for PD patients vs controls were 5 vs 6% for FFM, 8 vs 8% for LTM(arm) and 7 vs 8% for LTM(leg).

CONCLUSION

Eight-polar BIA offers accurate estimates of total and appendicular body composition in PD patients, provided that population-specific equations are used.

A Randomized Trial of Steroid Avoidance in Renal Transplant Patients Treated with Everolimus and Cyclosporine

In this randomized trial renal transplant recipients were treated with basiliximab, everolimus 3 mg/day, low-dose CsA. At transplantation, patients were randomized to stop steroids at the seventh day (group A) or to continue oral steroids in low doses (group B). Of the 113 patients enrolled, 65 were randomized to group A and 68 to group B. All patients were followed for 2 years. During the study 28 (43%) group A patients required reintroduced corticosteroids. One patient died, in group B. The Graft survival rate was 97% in group A and 90% in group B. There were more biopsy-proven rejections in group A (32% vs 16%; P = .044). The mean creatinine clearance was 54 +/- 21 mL/min in group A vs 56 +/- 22 mL/min in group B. Mean levels of serum cholesterol tended to be lower in group A, but the difference was of borderline significance (191 +/- 91 vs 251 +/- 188 mg/dL; P = .07). Vascular thrombosis (0 vs 5) and pneumonia requiring hospitalization (2 vs 7) tended to be more frequent in group B. Only three cases of CMV infection (1 vs 2) occurred. An immunosuppressive therapy with everolimus and low-dose CsA allows one to obtain excellent renal graft survival and stable graft function at 2 years. Early interruption of steroids in patients treated with this regimen may increase the risk of acute rejection, but neither affects graft survival nor graft function, while possibly reducing the risk of hyperlipemia and vascular thrombosis. About 60% of patients given everolimus and low-dose CsA can definitively stop steroids after 1 week.

[Early kidney-pancreas transplantation in type 1 diabetics prevents hemodialysis]

BACKGROUND

The life-expectancy of type 1 diabetics (T1D) on dialysis is still shorter than that of non-diabetics. Pancreas transplantation (PT) in its different modalities should be considered as a life-saving procedure.

METHODS

We analyzed our referral activity of T1D to PT from 1992. Since 2002, we have created a kidney and diabetes out-patient clinic devoted to the prevention of diabetic nephropathy and to the early referral of suitable T1D to combined kidney- pancreas transplantation (KPT) and isolated pancreas (PTA).

RESULTS

In the last 14 yrs, 25 T1D underwent KP in our district (620000 inhabitants). At the beginning, KPT was performed abroad, but then the borders were closed. After stopping in the mid 1990s, KP activity restarted addressing preemptive KPT and PTA. Currently, only one patient is on dialysis while awaiting KPT. Four T1D were evaluated and excluded from the list on medical grounds; two patients are on the list and a further two patients are currently under evaluation.

CONCLUSIONS

The implementation of a cooperative network among dialysis and transplant centers, supported by devoted out-patient clinics allowed the effective prevention of the dialysis requirement in T1D. Out-patient clinics devoted to diabetic nephropathy should play a pro-active role in preemptive KP, including the 'new' option of islet transplantation according to the Edmonton protocol.

[Malignant neoplasia and kidney transplantation. Retrospective analysis of data on the population having kidney transplantation with de novo neoplasia in the setting of the AIRT]

BACKGROUND

In transplanted patients undergoing immunossuppressive therapy the incidence of malignant neoplasia is 3-4 times higher than in the general population. Aim of the present study was to evaluate the prevalence of different tumours and the links between modulation of immunosuppressive therapy and patient and graft survival.

PATIENTS

We evaluated 2029 kidney-transplanted patients from four Transplant Centres (Bari, Bologna, Modena, Novara) belonging to the Associazione InterRegionale Trapianti (AIRT).

RESULTS

The incidence of neoplastic disease after transplantation was 3.9% in our population with a median time between transplantation and clinical onset of 23 months. We demonstrated a significant difference in the geographical distribution of different tumours. We did not observe any correlation with specific immunosuppressive drugs. Finally, dramatic reduction of the immunosuppression levels did not modify either the patients' or the graft's survival.

CONCLUSIONS

Several factors can influence the post-transplant onset of neoplastic diseases with immunosuppressive therapy playing a pivotal role. The implementation of a National Registry would be the first step in an attempt to optimise immunosuppression in this particular group of patient's.

[HCV+ patients on the waiting list for kidney transplantation. Retrospective analysis of data on the patient population with hepatitis C on the waiting list for kidney transplantation in the setting of the AIRT]

BACKGROUND

HCV infection in hemodialysis is still a matter of debate from an epidemiological and clinical point of view. Evaluation criteria for HCV-infected patients as transplant candidates are still not adequately standardized. Aims of the present study were to investigate: 1. the percentage of HCV positive patients on the waiting list of three Italian regions belonging to the Associazione InterRegionale Trapianti (AIRT); 2. to analyze the clinical approach in the evaluation of these patients in the attempt to define national guidelines for their pre- and post-transplant management.

PATIENTS

We evaluated 2045 uremic patients on the waiting lists of four transplant centers (Bari, Bologna, Modena, Novara) belonging to AIRT at 31/12/2002.

RESULTS

The overall prevalence of HCV positive patients was 14.2%, with a peak in the Puglia waiting list. The most common screening tests were AST and ALT serum levels and viral load (HCV RNA). Although there is a clear evidence that histological parameters are the main diagnostic and prognostic markers, a liver biopsy was performed in only 9.5% of patients. An even smaller percentage of HCV-infected patients underwent anti-viral therapy.

CONCLUSIONS

Our retrospective analysis evidenced the need to improve common clinical strategies in approaching HCV-infected canditates to renal transplantation in the attempt to improve their post-transplant outcome.

Liver and kidney foreign bodies granulomatosis in a patient with malocclusion, bruxism, and worn dental prostheses

Granulomatous reactions caused by foreign bodies have been described in drug abusers, in subjects exposed to occupational pollutants, and more rarely, in association with the use of prosthetic devices. We describe a 62-year-old patient with multiorgan parenchymal granulomatosis caused by inorganic debris of unknown origin. The patient presented with fever, hepatosplenomegaly, progressive cholestasis, and acute renal failure. Liver and kidney biopsies showed the presence of noncaseating epithelioid giant-cell granulomas containing scattered polarizable particles. Similar particles were also present in stools. Studies by innovative scanning electron microscopy and energy-dispersive microanalytical techniques showed that the particles isolated in liver, kidney, and stools were made by feldspars, the main component of porcelain. No occupational or environmental exposure to these materials could be identified in this patient and the only reliable source of the porcelain debris turned out to be constituted by 2 dental bridges evidently worn because of a possible inappropriate construction, malocclusion, and bruxism. The porcelain of the dental prostheses had the same elemental spectrum of the particles isolated from stool specimens and liver-kidney granuloma. After identification of the dental prostheses as the most likely source of ceramic debris, and after their removal, the particles from stool specimens disappeared. The patient was then treated with steroids leading to a remission of the clinical symptoms and a decrease in granulomatous inflammatory reaction in both liver and kidney. This is the first report suggesting that a foreign body systemic granulomatosis can be associated with worn dental prostheses.

Kidney preservation with university of Wisconsin and Celsior solution: a prospective multicenter randomized study

BACKGROUND

Although the University of Wisconsin (U.W.) solution continues to be the most commonly used for intra-abdominal organs, a new solution, Celsior, already used for heart and lungs, has been proposed for kidney and liver preservation. The aim of this research was to assess the effect of Celsior as compared with U.W. on immediate graft function and a 2-year follow-up of kidney transplants.

METHODS

A prospective multicenter randomized study was designed to evaluate the efficacy of the Celsior solution in the clinical preservation of the kidney. In this report, we present the data collected as of September 2000. One hundred donors were included in the trial resulting in 187 renal transplants. Ninety-nine kidneys were stored in Celsior solution and 88 in U.W. solution. The groups were comparable with regard to donor and recipient characteristics.

RESULTS

Delayed graft function occurred in 31.3% of the Celsior group and in 33.9% of the U.W. group (P=n.s.). Mean serum creatinine levels and mean daily urinary output were also comparable. Two year graft survival in kidneys preserved with Celsior was 84% as compared with 75% for U.W.-preserved kidneys without any significant statistical difference.

CONCLUSIONS

Our data show that the preservation of kidneys in Celsior solution in a clinical setting is equivalent to that of U.W. solution. When using Celsior during multiple-organ donor harvesting it would be possible to perform an in situ flush of all intra-abdominal and intrathoracic organs with a single cold storage solution.

Biofilms invade nephrology: effects in hemodialysis

Bacteria attach to surfaces and aggregate in a biopolymer matrix to form biofilm. Studies on biofilm have shown its presence in many prosthetic devices used in nephrology as well as in fluid pathways of hemodialysis plants and monitors. Once present, this community of bacteria increases resistance to biocide due to slime production and, as a result, chemical products for dialysis monitor disinfection and descaling procedures do not result in an effective treatment. Ultrapure dialysate is a goal in modern hemodialysis, and ultrafiltration is used to obtain sterile and apyrogen fluids. Microbial colonisation of ultrafilters may occur if, due to inadequate disinfection protocols, membrane is exposed to persistent bacterial contamination, and biofilm is allowed to form and to grow. As more and more data link final dialysate microbial contamination to clinical effects of bioincompatibility from chronic inflammation in dialysis patients, attention has to be focused on possibilities of biofilm avoidance.

Changes in conjugated linoleic acid and its metabolites in patients with chronic renal failure

BACKGROUND

Conjugated linoleic acid (CLA) is a mixture of isomers of linoleic acid with conjugated double bonds that constitutes the most abundant fatty acid with conjugated dienes (CDs) in humans. CLA, erroneously considered in the past as a product of lipoperoxidation, has a dietary origin and has shown to possess anticarcinogenic and anti-atherogenic activity, mainly in animal studies. CLA can be metabolized to conjugated linolenic acid (CD18:3) and to conjugated eicosatrienoic acid (CD20:3) and these metabolites may be implicated in CLA activity. Because of the presence of dyslipidemia and the high incidence of cardiovascular and neoplastic diseases in uremic patients, we evaluated CLA and its metabolites in these patients in order to evaluate their metabolism and site distribution.

METHODS

We measured CLA, CD18:3, CD20:3, CD fatty acid hydroperoxides (lipoperoxidation products), and linoleic acid in the plasma, adipose tissue, and red blood cell (RBC) membranes by using high-pressure liquid chromatography in the following groups: (1) 23 chronic renal failure (CRF) patients with creatine clearance (CCr)> 10 mL/min (26.2 +/- 16.7); (2) 21 end-stage CRF patients in conservative treatment with CCr <10 mL/min (6.8 +/- 1.8); (3) 30 hemodialysis (HD) patients; and (4) 30 healthy controls.

RESULTS

The incorporation of CLA, CD18:3, and CD20:3 in RBC membranes was significantly reduced in group 1 and was even more reduced in groups 2 and 3. CLA significantly increased both in the plasma and adipose tissue of end-stage CRF patients only. CD18:3 and CD20:3 did not change in the plasma and adipose tissue of any group. No significant changes in linoleic acid and CD fatty acid hydroperoxides were found.

CONCLUSIONS

The alterations of CD in CRF patients are not due to lipoperoxidation. The increased levels of CLA in plasma and adipose tissue of end-stage CRF patients may be due either to a reduced metabolization of CLA to CD18:3 and CD20:3, or to an altered site distribution with reduced incorporation in cellular membranes and accumulation in the plasma and adipose tissue. The clinical significance of these changes remains to be investigated.

Influence of different hemodialysis membranes on red blood cell susceptibility to oxidative stress

Oxidative stress is crucial in red blood cell (RBC) damage induced by activated neutrophils in in vitro experiments. The aim of the study was to evaluate whether the bioincompatibility phenomena occurring during hemodialysis (HD) (where neutrophil activation with increased free radical production is well documented) may have detrimental effects on RBC. We evaluated RBC susceptibility to oxidative stress before and after HD in 15 patients using Cuprophan, cellulose triacetate, and polysulfone membrane. RBC were incubated with t-butyl hydroperoxide as an oxidizing agent both in the presence and in the absence of the catalase inhibitor sodium azide. The level of malonaldehyde (MDA), a product of lipid peroxidation, was measured at 0, 5, 10, 15, and 30 min of incubation. When Cuprophan membrane was used, the MDA production was significantly higher after HD, indicating an increased susceptibility to oxidative stress in comparison to pre-HD. The addition of sodium azide enhanced this phenomenon. Both cellulose triacetate and polysulfone membranes did not significantly influence RBC susceptibility to oxidative stress. Neither the level of RBC reduced glutathione nor the RBC glutathione redox ratio changed significantly during HD with any of the membranes used. The RBC susceptibility to oxidative stress was influenced in different ways according to the dialysis membrane used, being increased only when using the more bioincompatible membrane Cuprophan, where neutrophil activation with increased free radical production is well documented. The alterations found in this study might contribute to the reduced RBC longevity of HD patients where a bioincompatible membrane is used.

Surface antigen expression and platelet neutrophil interactions in haemodialysis

BACKGROUND

There is increasing evidence to show the clinical implications of membrane biocompatibility in haemodialysis therapy.

METHODS

We conducted a cross-over clinical study examining the clinical biocompatibility profile of three derivatised cellulosic membranes obtained by means of different modifications to the cellulose polymer (haemophan, cellulose diacetate, benzyl cellulose) in comparison to the parent polymer (cuprophan) and a reference synthetic membrane (polysulfone).

RESULTS

In terms of leukopenia production, derivatised cellulosic membranes were generally intermediate between cuprophan and polysulfone, haemophan being more marked than the other two membranes. Upregulation of CD11b/CD18 molecule on neutrophils was found with all membranes, to a greater extent with the dialyser containing cuprophan. The expression of CD11b/CD18 on monocytes was slightly affected with cuprophan only. The neutrophil and monocyte counts throughout the entire dialysis session showed a much better correlation with the cellular expression of sialyl-Lewis x (CD15s) molecule than with CD11b/CD18 expression. An increased formation of platelet-neutrophil coaggregates occurred at 15 and 30 min during dialysis with all membranes but benzyl cellulose, the increase with cuprophan being higher than with the other membranes. In concomitance with the increase in platelet-neutrophil coaggregation, an increased hydrogen peroxide production by neutrophils occurred, which proved to be significantly higher compared to the unchanged neutrophil hydrogen peroxide production during HD with benzyl cellulose.

CONCLUSIONS

Our results demonstrate that derivatised cellulose is associated with a considerable improvement in the clinical biocompatibility profile. Derivatised cellulosic membranes show many similarities but also several significant differences which very likely stem from the different type of structural modification to the cellulose polymer rather than from the degree of hydroxyl group replacement.

Leukocyte adhesion molecules and leukocyte-platelet interactions during hemodialysis: effects of different synthetic membranes

Membranes made from synthetic polymers, in general, are considered as being biocompatible membranes and tend to be treated as a homogeneous group. However, all of these membranes have multiple and different characteristics that may contribute to interactions with blood components. As a consequence, the biocompatibility profile of synthetic membranes may vary. In the present cross-over study, we examined by flow cytometry the effects (expressed as % change from predialysis values) of three different synthetic polymers (polysulfone, PSF; polyacrylonitrile-co-sodium methallyl sulfonate, AN69; ethylenevinylalcohol, EVAL) on the expression of leukocyte adhesion molecules (CD11b/CD18, CD15s) and the interactions between leukocytes and platelets under conditions of routine clinical use. For neutrophils, a statistically significant difference was found in CD15s expression for EVAL as compared to AN69 (p<0.05) and in CD11b/CD18 expression for PSF as compared to both EVAL (p<0.01) and AN69 (p<0.05). No difference between membranes was found on the expression of such adhesive molecules on monocytes. Significant differences in platelet-neutrophil (but not in platelet-monocyte) coaggregate formation were observed between PSF and both EVAL (p<0.001) and AN69 (p<0.01). Reactive oxygen species production by neutrophil population during hemodialysis was significantly different between each pair of synthetic polymers (PSF vs EVAL, p<0.001; PSF vs AN69, p<0.001; AN69 vs EVAL, p<0.05). Our data demonstrate that in terms of leukocyte adhesion receptors and platelet-leukocyte interactions, the biocompatibility profile of the synthetic membranes polysulphone, AN69 and EVAL shows many similarities but also several significant differences. Our results support the concept that biocompatibility evaluation of each membrane should be based exclusively on data generated by that membrane in order to avoid errors based on assumptions about group characteristics.

Retention of limulus amoebocyte lysate reactive bacterial products by polysulfone dialyzers is affected by the type of disinfectant

To reduce the level of contamination by bacterial products, ultrafiltration systems have been introduced and validated for their capacity to block the passage of bacterial components reactive to the limulus amoebocyte lysate (LAL) test. In this study, the absorptive capacity of polysulfone membranes undergoing disinfection cycles with free chlorine and peracetic acid were evaluated at various concentrations and contact times. The results of this study implicate a relevant physicochemical derangement of the polysulfone membranes treated with sodium hypochlorite but not with peracetic acid, diluted peracetic acid (Dialox) or Amuchina. The implications for the practical use of ultrafilters are discussed.

Serum levels of soluble adhesion molecules in chronic renal failure and dialysis patients

Besides cell-bound adhesion molecules, which are of fundamental importance to a large number of physiological and pathological processes, soluble forms of adhesion molecules have been detected in the circulating blood in recent years. Circulating soluble adhesion molecules appear to be biologically active, and raised levels have been reported in a variety of disorders. In the present study, we used ELISA to measure the serum levels of four soluble adhesion molecules in 23 undialyzed patients with chronic renal failure (CRF), 13 patients on continuous ambulatory peritoneal dialysis (CAPD), 17 on chronic hemodialysis (HD) and 18 healthy controls having a similar mean and distribution of ages. The investigated soluble (s) molecules included intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1), sE-selectin and sP-selectin. sICAM-1 was found to be elevated in patients with CRF (p < 0.05), on CAPD (p < 0.02) and HD (p < 0.0001) compared with the controls but levels did not differ between the three patient groups. The higher sVCAM-1 values found in CRF (p < 0.02), CAPD (p < 0.05) and HD (p < 0.0001) as compared to controls again failed to differentiate the three groups of patients. Soluble E-selectin was also raised in the three groups (p < 0.0001) with no difference between them. Increased sP-selectin was found in CRF (p < 0.05), CAPD (p < 0.02) and in HD patients (p < 0.0001) compared to controls, and levels in HD were significantly higher (p < 0.02) than in CRF patients. Predialysis serum molecule levels did not differ between HD patients treated with cuprophan or with polyacrylonitrile dialyzers. HD sessions with both dialyzers had no effect on sICAM-1, while a decrease (p < 0.02) in sP-selectin was found after dialysis with cuprophan. In undialyzed patients with CRF, regression analysis showed a strong linear correlation between serum creatinine and serum levels of each soluble molecule. These results demonstrate that serum levels of soluble adhesion molecules ICAM-1, VCAM-1, E-selectin and P-selectin are elevated in both undialyzed patients with CRF and patients on CAPD or HD. The elevated serum levels of these proteins probably reflect inadequate clearance as well as enhanced synthesis/release.

Phenotypic Characterization of Kidney Infiltrating Cell Subsets in Idiopathic Acute Interstitial Nephritis Associated with Uveitis: Evidence for a Cell-Mediated Immune Disease

The association of acute interstitial nephritis (AIN) and anterior uveitis without determined cause is quite rare. This disease entity is manifested by uveitis which may precede, occur concomitantly with, or follow AIN. Renal involvement is characterized by acute renal failure which is usually associated with a diffuse interstitial infiltration mainly by mononuclear cells. We report here the clinicopathological features in two cases of this association showing a different time course evolution of the renal disease. Repeat kidney biopsy allowed to study in different points of the disease process both the histological picture and the phenotypic characterization (by an immunohistochemical method) of cells infiltrating the renal interstitium. Immunohistochemical analysis of renal tissue revealed that interstitial infiltrate was primarily composed of T lymphocytes (mainly helper-inducer T cells) and monocytes/macrophages. A clear predominance of memory T lymphocytes (CD45RO+) in the interstitial infiltration was found. These cells persisted in the renal interstitium of the patient in whom renal function remained persistently impaired. The cellular profile of immunocompetent cells in renal lesions suggests a major role for cell-mediated immunity in the development of idiopathic AIN associated with uveitis.

Role of dyslipidemia in the progression of chronic renal disease

The connection between lipids and the rate of progression of chronic renal disease was retrospectively examined in 70 patients who were divided into 2 groups according to their baseline creatinine clearance (CCr): Group 1 (Gp1) contained 30 patients with CCr 60-40 mL/min followed for 40.0 +/- 13.3 months; Group 2 (G2) contained 40 patients with CCr 39-15 mL/min followed for 39.0 +/- 18.2 months. The following parameters were considered: basal and final CCr proteinuria per unit of CCr (UProt/CCr); the difference between final and basal UProt/CCr (delta UProt/CCr); the change in CCr/month (delta CCr); baseline triglycerides (TG), total (TC), HDL (HDLC) and LDL (LDLC) cholesterol, Apo AI, Apo B, Lp(a). Besides in basal CCr the 2 groups significantly differed in the final CCr, final UProt/CCr, delta UProt/CCr, delta CCr. No differences were observed concerning lipid parameters except for Lp(a) (G1 14.8 +/- 13.6, G2 28.7 +/- 27.4 mg/dL; p < 0.05). Baseline TG (G1 184.1 +/- 61.3, G2 187.5 +/- 72.1 mg/dL) and Apo B (only G2 1.05 +/- 0.32 g/L) were significantly higher than normal subjects and the Apo AI/Apo B ratio (G1 1.42 +/- 0.43, G2 1.33 +/- 0.45) were significantly lower than in normal subjects. delta CCr, while inversely correlated in both groups with delta UProt/CCr (p < 0.01), only in G2 did it correlate directly with the Apo AI/Apo B ratio (p < 0.05) and inversely with Apo B and LDLC (p < 0.05). Although a correlation between Lp(a) and delta CCr was not found, 20/22 patients (3/5 G1, 17/17 G2) with a level > 30 mg% ran a progressive course. A natural progression of CRI, heralded by an increasing UProt, is highly frequent when baseline CCr is < 40 mL/min; only then lipids seem to add a burden to the renal damage.