[Hemodiafiltration with endogenous reinfusion in chronic inflammation: a possible therapeutic alternative?]. / L'impiego dell' Emodiafiltrazione con reinfusione endogena (HFR) nell'infiammazione cronica idiopatica: una possibile alternativa terapeutica?

The patients under maintenance haemodialysis (HD) continue to have an unacceptably excess of mortality compared to general population, that may be explained by high prevalence of inflammation that significantly influences the survival of these patients. Indeed, chronic inflammation is very common in HD and it may cause malnutrition and progression of atherosclerotic disease by several pathogenetic mechanisms triggered by pro-inflammatory cytokines. Currently no pharmacological intervention is specifically targeted the idiopathic chronic inflammation. Hemodiafiltration with endogenous reinfusion (HFR) is a dialysis technique, highly biocompatible, that combines three depurative mechanisms: diffusion, convection and absorption. The ultrafiltrate is obtained from convective section of dialyzer (convection). It is regenerated by passing through the adsorbent macro-porous synthetic resin cartridge (absorption) and then it is reinfused into the second section of the filter (diffusion). This resin cartridge is able to absorb cytokines and other uremic toxins, whereas allows to pass nutrients and antioxidants, as amino acids and vitamins, with a consequent decrement of inflammation and oxidative stress. These characteristics suggest the use of HFR in HD patients affected by overt and idiopathic chronic inflammation. In these patients, we observed that the switching from Bic-HD to HFR allowed an improvement of inflammatory as testified by a significant decrement of serum levels of CRP IL-6, IL-1 and TNF- and a significant increase of albumin and pre-albumin. Whether these favorable effects may modify the outcomes of these high-risk patients, needs to be confirmed by studies ad-hoc.

Intradialytic changes of plasma amino acid levels: effect of hemodiafiltration with endogenous reinfusion versus acetate-free biofiltration.

During hemodialysis, amino acids (AA) are lost in the ultrafiltrate with consequent modification of their plasma profile. The aim of this cross-sectional study was to evaluate intradialytic changes of plasma AA levels during a single session of hemodiafiltration with endogenous reinfusion (HFR) versus acetate-free biofiltration (AFB). 48 patients chronically treated with HFR or AFB were matched 1:1 for age, gender, Kt/V and diabetes. Blood samples were collected at the beginning and the end of dialysis. Baseline plasma levels (µmol/l) of total AA (3,176 ± 722), essential AA (889 ± 221), and branched chain AA (459 ± 140) levels in HFR were similar to those in AFB (3,399 ± 621, 938 ± 277, and 463 ± 71, respectively). Plasma intradialytic AA levels did not change in HFR, while in AFB there was a reduction by about 25%. In conclusion, as compared with AFB, HFR has a sparing effect on AA loss due to the lack of adsorption by cartridge and to their complete reinfusion in blood.

[Clinical experience in HFR with a new resin-only sorbent cartridge]. / Sperimentazione clinica in HFR di una cartuccia rigenerante priva di carbone.

Adsorbent therapies have become increasingly popular over the last several years as they permit an additional method to selectively or non-selectively remove toxins. Adsorbents offer a unique removal strategy as they have an extremely high adsorption capacity due to their great surface area. This paper describes experiments that utilized a synthetic divinylbenzene styrenic resin cartridge to remove uremic toxins from chronic renal failure patients. The resin-only cartridge was tested as an alternative after a small number of patients (primarily taking ACE inhibitors) experienced gastrointestinal problems using hemodiafiltration with on-line regeneration (HFR). Subsequent laboratory evidence suggested that the particular carbon used in the cartridge was able to activate contact phase activation. This could potentially cause problems in patients taking ACE inhibitors, as they are unable to degrade bradykinin efficiently. The resin-only cartridge was tested in at 6 centers throughout Italy and included patients that had experienced previous reactions to the carbon-resin cartridge. At the conclusion of the study, no adverse reactions were reported and the cartridge exhibited excellent removal of b2 microglobulin and angiogenin.

[Aspects of the on-line hemodiafiltration with regeneration and reinfusion of the ultrafiltrate (HFR): multicenter study]. / Aspetti dell'emodiafiltrazione on-line con rigenerazione e reinfusione dell'ultrafiltrato (HFR): uno studio multicentrico.

Despite technological advances in dialysis treatment, survival, morbidity and the quality of life in hemodialysis (HD) patients are affected by long-term complications, often related to the treatment itself. Among these complications, moderate protein and caloric malnutrition are present in approximately 30% of dialysis patients and are viewed as major contributors to increased mortality. In malnutrition pathogenesis, great importance is given to protein catabolism and to the loss of somatic protein and amino acids during dialysis. On the contrary, toxin clearance is believed to influence, positively, both protein anabolism and dietary protein intake. In hemodiafiltration (HDF), the clearance process is potentiated by three mechanisms (diffusion, convection and adsorption) and this could have a favorable effect on malnutrition. In addition, the reinfusion of regenerated ultrafiltrate (UF) would avoid the loss of large amounts of useful solutes as occurs with standard HD. In fact, all amino acids are present in the UF, which is not important in standard HD, but could be a problem in hemodiafiltration reinfusion (HFR). We treated 16 patients with HFR during the previous 3 months (the study will last for 12 months). Patients had been previously treated with bicarbonate dialysis for at least 6 months. The clinical tolerance of HFR was excellent and the technique appeared to be quite simple. The preliminary biochemical results demonstrated the stabilization of some parameters (such as urea and uric acid) with an adequate clearance of small molecules, while variables related to nutritional status (body weight, serum albumin and serum transferrin) did not change substantially. Surprisingly, the loss of both branched chain amino acids (BCAA) and essential amino acids (EAA) seemed slightly lower in HFR compared with standard HD. However, the reduced loss of amino acids (AA) observed with HFR should take into account other factors, such as absorption on adsorbent material and the basal plasma AA concentrations. Therefore, although each patient is in control of himself, it is difficult to draw any definite conclusions after only 3 months. However, it is evident that the loss of AA in HFR is quite modest and is not increased by the fact that it is a hemofiltration technique with all the consequent positive effects.

[Can anemia be corrected in hemodialysis patients with thalassaemia minor? ]. / La correzione dell'anemia nei pazienti in emodialisi con Talassemia minor e' possibile?

BACKGROUND: Anemia is an important negative prognostic factor for dialysis patients, whose correction reduces hospitalisation and mortality. Besides, the presence of the thalassaemia minor (Thal-m) in haemodialysed patients causes erythropoietin resistance and more serious anemia. The goal of this study is the correction of anemia (Hb >11 g/dL) in haemodialysed Thal-m patients. MATERIALS AND METHODS: Multicentric, prospective and controlled 12-month study for the correction of anemia (up to values ranging from 11 to 12 g/dL) followed by a 12-month observation period. Ten Thal-m patients with inadequate anemia correction were studied after therapy with rHuEPO. Their age at the beginning of the study was 62.8+/-4 years while their dialytic age was 89+/-20 months. RESULTS: During the study we observed no changes in dry weight (p=NS), no increase in interdialytic weight (p=NS), cardiac frequency (p=NS), serum albumin (p=NS), serum aluminium (p=NS), PTH (p=NS), URR (p=NS), flow FAV (p=NS), TSAT (p=NS) and ferritin (p=NS) (maintained at their optimal values by means of intravenous therapy with trivalent iron. The hypotensive therapy (1.6 drug/patient/year) required no modifications during the 24-month study. The rHuEPO dose varied from 200.3+/-94.3 to 286.6+/-116.2, 317.0+/-119.5, 446.9+/-142.3, and 407.0+/-130.5 U/kg/wk (p < 0.0001 vs. initial value) (from the start to the 3rd, 6th, 9th and 12th month, respectively). The dose was subsequently reduced to 385.2+/-119.7 U/kg/wk at 15 months (p < 0.0001 vs. initial value) and remained unchanged until the end of the study. Simultaneously, the Hb values at corresponding times were 9.2+/-0.9, 9.4+/-1.1, 10.2+/-1.4, 10.9+/-1.5, 11.2+/-1.4 and 11.0+/-1.4 (p=0.002 vs. initial value). The correction of anemia produced progressive reduction in cardiac mass from 141+/-12 to 120+/-10 and 110+/-8 g/mq at the beginning, 12th month and 24th month (p < 0.0001), respectively. During the study the hospitalisation time was 4.3+/-1.2 day/patient/year during the 3-month run-in period, 3.4+/-1.4 day/patient/year during the first year, and 3.1+/-1.1 day/patient/year during the second year (p=0.098). CONCLUSIONS: In conclusion we can say that the question of Thal-m in dialysis patients cannot be ignored or underestimated. The rHuEPO dosage in these patients must be reassessed (a dose of 450 U/kg/wk corresponding to approximately 60,000 units/week is acceptable and does not produce an increase in side effects if the correction is done gradually); moreover, other factors responsible for EPO-resistance must be eliminated (hyperthyroidism, aluminium intoxication, iron overloaded or deficiency).