Delayed graft function and chronic allograft nephropathy: diagnostic and prognostic role of neutrophil gelatinase-associated lipocalin.

CONTEXT: Available markers are not reliable parameters to early detect kidney injury in transplanted patients. OBJECTIVE: Examine neutrophil gelatinase associated lipocalin (NGAL) in early detection of delayed graft function (DGF) and as a long-term predictor of graft outcome. PATIENTS AND METHODS: NGAL was evaluated in 124 transplanted patients. RESULTS: Urinary NGAL levels were associated to a 10% (HR: 1.10; 95% CI: 1.04-1.25; p < 0.001) and 15% (HR: 1.15; 95% CI: 1.09-1.26; p < 0.001) increased risk of DGF and allograft nephropathy progression, respectively. CONCLUSION: NGAL reflects the entity of renal impairment in transplanted patients, representing a biomarker and an independent risk factor for DGF and chronic allograft nephropathy progression.

Apelin and copeptin: two opposite biomarkers associated with kidney function decline and cyst growth in autosomal dominant polycystic kidney disease.

Vasopressin (AVP) plays a detrimental role in autosomal dominant polycystic kidney disease (ADPKD). Copeptin represents a measurable substitute for circulating AVP whereas apelin counteracts AVP signaling. The aim of this study was to investigate the predictive value of apelin and copeptin for the progression of ADPKD disease. 52 ADPKD patients were enrolled and followed until the end of the observation period or the primary study endpoint was reached, defined by the combined outcome of decrease of glomerular filtration rate associated with a total renal volume increase. Receiver operating characteristics (ROC) analysis was employed for identifying the progression of renal disease and Kaplan-Meier curves assessed the renal survival. Adjusted risk estimates for progression endpoint and incident renal replacement therapy (RRT) were calculated using Cox proportional hazard regression analysis. ADPKD patients were characterized by lower apelin levels and higher copeptin levels when compared with healthy subjects. These biomarkers were strictly correlated with osmolality and markers of renal function. At ROC analysis, apelin and copeptin showed a very good diagnostic profile in identifying ADPKD progression. After the follow up of 24 months, 33 patients reached the endpoint. Cox proportional hazard regression analysis showed that apelin predicted renal disease progression and incident RRT independently of other potential confounders. Apelin is associated with kidney function decline in ADPKD, suggesting that it may be a new marker to predict kidney outcome.

Influence of CYP3A5 and ABCB1 gene polymorphisms and other factors on tacrolimus dosing in Caucasian liver and kidney transplant patients.

Tacrolimus is a substrate of cytochrome P4503A (CYP3A) enzymes as well as of the drug transporter ABCB1. We have investigated the possible influence of CYP3A5 and ABCB1 single nucleotide polymorphisms (SNPs) and other factors (e.g. albumin, hematocrit and steroids) on tacrolimus blood levels achieved in a population of Caucasian liver (n=51) and kidney (n=50) transplant recipients. At 1, 3 and 6 months after transplantation, tacrolimus doses (mg/kg/day) and trough blood levels (C0) were recorded and the weight-adjusted tacrolimus dosage (mg/kg/day) was calculated. Polymerase chain reaction followed by restriction fragment length polymorphism analysis was used for genotyping CYP3A5*1 and *3 [6986A>G] as well as ABCB1 at exons 21 [2677G>T/A] and 26 [3435C>T] in both liver transplant donors and recipients and in kidney transplant recipients. Of the 152 subjects studied, 84.9% showed a CYP3A5*3/*3 genotype. The total frequency of the allelic variant *3 was 93%. For the G2677T/A and C3435T polymorphisms the total frequencies of the allelic variants T/A and T were 44.7 and 46.7%, respectively. At 1, 3 and 6 months after transplantation the dose-adjusted C0 levels were significantly lower in patients with one copy of the *1 allele compared to those homozygous for the *3 allele. In the case of liver transplant patients the tacrolimus dose requirements were dominantly influenced by the polymorphisms of the CYP3A5 gene in the donors. With regard to the ABCB1 SNPs, in general they did not show any appreciable influence on tacrolimus dosing requirements; however, kidney transplant recipients carrying the 2677T/A allele required significantly higher daily tacrolimus doses than subjects homozygous for the wild-type allele. Identification of CYP3A5 single nucleotide polymorphisms prior to transplantation could contribute to evaluate the appropriate initial dosage of tacrolimus in the patients.

The role of basiliximab in the evolving renal transplantation immunosuppression protocol.

Basiliximab is a chimeric mouse-human monoclonal antibody directed against the alpha chain of the interleukin-2 (IL-2) receptor on activated T lymphocytes. It was shown in phase III trials to reduce the number and severity of acute rejection episodes in the first year following renal transplantation in adults and children, with a reasonable cost-benefit ratio. The drug does not increase the incidence of opportunistic infections or malignancies above baseline in patients treated with conventional calcineurin inhibitor-based immunosuppression. In the field of renal transplantation, basiliximab does not increase kidney or patient survival, despite the reduction in the number of rejection episodes. Basiliximab may reduce the incidence of delayed graft function. In comparison with lymphocyte-depleting antibodies basiliximab appears to have equal efficacy in standard immunological risk patients. Recently, IL-2 receptor monoclonal antibodies have been used with the objective of reducing or eliminating the more toxic elements of the standard immunosuppression protocol. Several trials have incorporated basiliximab in protocols designed to avoid or withdraw rapidly corticosteroids, as well as protocols which substitute target-of-rapamycin (TOR) inhibitors for calcineurin inhibitors.

Behavior of vascular endothelial growth factor and erythropoietin throughout the menstrual cycle in healthy women.

OBJECTIVE: To evaluate any correlations between erythropoietin (EPO) and vascular endothelial growth factor (VEGF) levels in the serum and the menstrual fluid of healthy women during the different phases of the menstrual cycle. STUDY DESIGN: Blood samples from 25 healthy female volunteers were obtained for serum VEGF and EPO detection on the 1st, 7th, 14th, 21st and 25th days of the menstrual cycle. Menstrual fluid samples for VEGF and EPO detection were obtained on the 1st and 4th days of menstruation. RESULTS: Circulating VEGF levels were found to increase in a stage-dependent cyclic manner. The mean VEGF concentration in menstrual blood on the 1st day of the cycle was significantly higher than the mean plasma value and was reduced to a significant extent on the 4th day of the cycle. We found no significant changes in serum EPO levels. Mean EPO concentration detected in menstrual blood was comparable to those in serum blood either on the 1st or 4th day of the menstrual cycle. CONCLUSION: During menstruation, a local production of VEGF occurs independent of systemic production, thus sustaining angiogenic activity in autonomous, independent ways. Our findings demonstrate the presence of an "open compartment" that reflects the systemic pattern of EPO at the uterine level that allows us to speculate on different effects beyond the angiogenic action of EPO.

Statins in the prevention of cardiovascular events in patients with renal failure.

HMG-CoA reductase inhibitors (statins) are among the most widely used hypolypemizing drugs with a pleiotropic activity. Numerous clinical trials have demonstrated that statins can have a significant effect in the prevention of cardiovascular diseases in the general population. In patients with renal failure, this drug preserves the hypolypemizing efficacy found in the general population without increasing their unwanted side-effects. The re-analysis of data from epidemiological studies conducted on the general population has confirmed that statins provide cardiovascular protection also in subjects with renal failure. These data have been partly confirmed by the findings made by 4D (Die Deutsche Diabetes Dialyse Studie) and Alert studies, conducted on diabetic patients on dialysis and patients with renal transplants, respectively. The results of other studies, such as AURORA, SHARP, REnal and Vascular End stage Disease, and ESPLANADE, clearly indicate that statins prevent cardiovascular disease in patients with renal insufficiency, just as they do in the general population.

Oxidative stress, sister chromatid exchanges and apoptosis in the pathogenesis of lymphocytopenia in ESRD patients.

BACKGROUND: In end-stage renal disease (ESRD) patients on hemodialysis (HD) there may be a link between oxidative stress, genomic damage and the tendency of peripheral lymphocytes to die by apoptosis. Our aim was to verify this hypothesis, and to ascertain whether the link, if present, could explain lymphopenia in uremic patients. METHODS: The series investigated comprised 55 participants: 30 HD patients on regular maintenance acetate-free bio-filtration (AFB) and 25 age-matched healthy volunteers. One blood sample was drawn from the cubital vein of each participant. In HD patients, samples were drawn 3 times: predialytic, postdialytic and interdialytic (24 hours after the end of the session). Thiobarbituric acid reactants (TBARs), sister chromatid exchange (SCE) rate, high frequency cells (HFCs), total circulating lymphocytes and the percentage of circulating apoptotic lymphocytes were assayed in all samples. A statistical analysis of the findings was made using multiple and linear regression. RESULTS: In AFB patients, TBAR levels appeared higher than in controls, even at baseline (2.15 +/- 0.5 micromol/L vs. 1.20 +/- 0.4 micromol/L; p < 0.05). The highest peak occurred at the end of the session (3.2 +/- 0.4 micromol/L; p < 0.05 vs. basal), and a prompt return to basal values was observed 24 hours later (2.2 +/- 0.6 micromol/L, p < 0.5 vs. basal). In AFB patients, the per-centages of HFCs (8.63% vs. 3%; p < 0.05), SCE (6 +/- 0.6 vs. 4.65 +/- 2.18; p < 0.04) and apoptotic lymphocytes (3-fold) were greater than in controls, even at baseline, whereas the values for total lymphocytes were lower (1,140 +/- 652 vs. 1,590 +/- 822). After an AFB session the differences between patients and control values appeared greater (HFCs, 16.81%, p < 0.04 vs. basal; SCE, 7.02 +/- 1.2, p < 0.03; apoptotic lymphocytes 3.5-fold greater than control values). Twenty-four hours later, a further increase was observed in the expression of genomic damage (HFCs, 50%, p < 0.05 vs. basal; SCE, 9.82 +/- 2.1, p < 0.03) and the percentage of apoptotic lymphocytes (4.7-fold greater than control values), while the lowest peak occurred for total circulating lymphocyte count (997 +/- 854, p < 0.04). At linear regression, a strong positive correlation was found between HFCs and TBARs at the beginning and at the end of the AFB session(r = 0.7, p < 0.03). With multiple regression analysis, a strong positive correlation was found between TBAR levels at the end of AFB session, HFC rate and apoptotic lymphocytes at 24 hours, with the last as the dependent variable (multiple r = 0.8, TBARs, beta = 0.51, p < 0.04; HFCs, beta = 0.43, p < 0.03). DISCUSSION AND CONCLUSIONS: An AFB session has an immediate impact, causing an increase in TBAR levels, genomic da-mage and lymphocytic apoptosis. Twenty-four hours after the session there was a further expression of genomic damage, and an increase in apoptosis, while the peak for lymphocytes dropped sharply. Our findings indicate that lymphopenia affecting end-stage renal disease (ESRD) patients may be strictly related to genomic damage exerted, at least in part, by TBARs, and to a dysregulation in programmed cell death.

Chromosomal damage and atherosclerosis. A protective effect from simvastatin.

In uremic patients, the frequency of sister chromatid exchanges appears markedly higher than in the general population. Statins are well known for their pleiotropic effects, which are independent of any reduction in cholesterol circulating levels. The aim of the present study was to determine the effects of exposure to escalating doses of simvastatin on the sister chromatid exchange rate in cultured lymphocytes in order to identify the influence of statin on genomic damage. Peripheral lymphocytic samples for culture were obtained from 25 healthy volunteers, 20 patients with documented carotid atherosclerosis and 30 atherosclerotic patients on maintenance regular acetate-free biofiltration. Hemodialyzed patients had a greater percentage of high frequency cells (50%) than healthy controls (3%) and a significantly higher average number of sister chromatid (9.82+/-2.1 vs. 4.65+/-2.18). The subgroup of hemodialyzed patients with high plaque score values was characterized by significantly greater values for both sister chromatid exchanges rate and high frequency cells percentage. Our findings demonstrate that there is an association between sister chromatid exchanges and high frequency cells rate and atherosclerosis in acetate-free biofiltration patients. In cultures with added simvastatin, high frequency cells percentages and mean sister chromatid exchanges levels were significantly lower than in cultures with an added vehicle alone, the reduction occurring in a dose-dependent fashion, above all in cultures from end stage renal disease patients. The findings, moreover, demonstrate new effects of simvastatin, which appeared to mitigate the expression of genomic damage in our model. However, it is not yet clear whether this effect is due to the prevention of genomic damage or to the potentiation of the DNA repair capacity. Statins may therefore have an anti-atherogenic action partly ascribable to their ability to provide protection against the development of atherosclerotic plaque.

Cardiorenal consequences of atherosclerosis and statins therapy: from the past to the future.

Complications from atherosclerosis cause most deaths in western countries, and their incidence appears to be markedly increasing in developing countries, thus suggesting a correlation that is directly proportional to social progress. In recent years, the different branches of medical research, from studies on vascular disease to those on lipid and glucose metabolism, and also clinical research on coronary, carotid and peripheral artery diseases, epidemiologic and pharmacologic research, have concentrated on these diseases with the common aim of reducing the incidence of cardiovascular diseases, and mortality. Scientific progress has greatly improved our understanding of the pathogenic mechanisms underlying the progression of cardiovascular disease, and efforts in this discipline now appear more necessary than ever.

Osteoprotegerin, IL-6, IL-1, TNF-alpha and TGF-beta concentrations during acetate-free biofiltration.

To ascertain the effect of acetate-free biofiltration (AFB), performed with polyacrilonitrile filters, on serum concentrations of osteoprotegerin (OPG) and other bone-acting cytokines (interleukin (IL) IL-1, IL-6, tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta)) in end-stage renal disease (ESRD) patients, we evaluated these parameters during an AFB session and 24 hr after it ended. In second time we verified the existence of eventual correlations among serum levels of all these cytokines at different times. We investigated 48 subjects: 24 healthy volunteers (controls) (12 females, 12 males, mean age 55 +/- 9 yrs) and 24 ESRD patients (12 females, 12 males, mean age 58 +/- 6.7 yrs, mean dialytic age 2.7 +/- 1.6 yrs, residual glomerular filtration rate (GFR) 2.3 +/- 0.6 ml/min). All dialyzed patients received regular AFB with polyacrilonitrile filters for 4 hr thrice-weekly. Statistical analysis showed significant increase in basal serum OPG, IL-6 and TNF-alpha concentrations in dialyzed patients compared to controls, while it did not show significant variations for the other cytokines. During the dialytic session, OPG and TGF-beta concentrations did not show significant variations, while serum TNF-alpha, IL-6 and IL-1 levels significantly decreased from the 1st hour of AFB. None of the cytokines showed significant differences between basal and interdialytic values. We did not find correlations between OPG, IL-1, IL-6, TNF-alpha and TGF-beta concentrations during hemodialytic sessions and during the interdialytic interval. It is our opinion that the lack of correlation between serum concentrations, observed in our study, could not exclude the presence of local interferences between OPG and the other cytokines.

The effect of two different protocols of potassium haemodiafiltration on QT dispersion.

BACKGROUND: The risk of developing cardiovascular diseases is higher in patients on haemodialysis than in the general population. These patients may develop arrhythmias that depend on the extra- and intracellular concentrations of potassium. ECG findings, particularly the QT interval and its dispersion (QT(d)) and the QT(c) (QT interval corrected for heart rate according to Bazett's formula) and its dispersion (QT(cd)), may be direct indicators of the risk of developing arrhythmia. METHODS: Our cohort comprised 28 patients who were dialysed for 3.5-4 h three times per week, first with haemodiafiltration with a constant potassium concentration (HDF) in the dialysis bath then with haemodiafiltration with variable concentrations of potassium (HDF(k)). ECGs were done at different time intervals: at the start of dialysis (T(0)), at 15 (T(15)), 45 (T(45)), 90 (T(90)) and 120 min (T(120)) after the beginning of the session, and at the end of treatment (T(end)). ECG-derived data (QT, QT(d), QT(c) and QT(cd)) were measured. At the same time points, plasma electrolytes, intra-erythrocytic potassium and the electrical membrane potential at rest (REMP) of the erythrocytic membrane were measured. RESULTS: Plasma potassium concentration diminished more gradually in HDF(k) than in HDF, the difference being statistically significant at T(15) and T(45) (P<0.05), and T(90) (P<0.01). The intra-erythrocytic potassium concentration remained constant throughout the observation period. In both HDF and HDF(k), REMP was lower at all points after T(0) (P<0.05), but the reduction was greater and more significant in HDF than in HDF(k) at T(15) and T(120) (P<0.05). ECG revealed a statistically significant diminution in HDF(k) vs HDF in the measures of dispersion of QT and QT(c) at T(15), T(90), T(120) and T(end) (P<0.01) and of QT(cd) at T(45) (P<0.05). The mean of QT(d), adjusted for plasma potassium, increased over time in HDF with large alternate mean increase and decrease peaks and error intervals. In HDF(k), instead, there was a progressive and constant diminution with minor error intervals. QT(cd) adjusted for plasma potassium had the same trend. A marked difference was found between the final values in standard HDF and those in HDF(k). CONCLUSIONS: HDF and HDF(k) have significantly different effects on QT(c). ECG data demonstrate that the risk of arrhythmia could be lower, with a variable removal of potassium during haemodialysis. With HDF but not HDF(k), hyperpolarization of the cell membrane is detected, and this could have a destabilizing effect on different types of cardiac cell, giving rise to retrograde circuits.

Brain and cancer: the protective role of erythropoietin.

Erythropoietin (Epo) is a pleiotropic agent, that is to say, it can act on several cell types in different ways. An independent system Epo/Epo receptor (EpoR) was detected in brain, leading to the hypothesis that this hormone could be involved in cerebral functions. Epo/EpoR expression changes during ontogenesis, thus indicating the importance of this system in neurodevelopment. Moreover, the hypoxia-induced production of Epo in the adult brain suggests that it could exert a neurotrophic and neuroprotective effect in case of brain injury. Epo could also influence neurotransmission, inducing neurotransmitters (NT) release. Epo therapy in anemic cancer patients is still a controversial issue, because of its possible action as a growth and an angiogenic factor. In our speculative hypothesis Epo could be involved in a "two steps process" that, after a neovascularization phase, leads to its down regulation. Moreover, Epo-activated signaling pathways could be modulated as possible targets to interfere in neoplastic cells cycle. In conclusion, treatment with rHuEpo could change therapeutical perspectives in different pathological conditions, such as central nervous system (CNS) diseases, but further studies are needed to clarify its physiopathological activities in different clinical fields.

An implantable telemetry platform system for in vivo monitoring of physiological parameters.

This paper describes a microcontroller-based multichannel telemetry system, suitable for in vivo monitoring of physiological parameters. The device can digitalize and transmit up to three analog signals coming from different sensors. The telemetry transmission is obtained by using a carrier frequency of 433.92 MHz and an amplitude-shift keying modulation. The signal data rate is 13 kb/s per channel. The digital microcontroller provides good flexibility and interesting performance, such as the threshold monitoring, the transmission error detection, and a low power consumption, thanks to the implementation of a sleep mode. The small overall size (less than 1 cm3), the power density compatible with current regulations for the design of implantable devices, and the dedicated packaging make the system suitable for in vivo monitoring in humans. The design, fabrication, operation, packaging, and performance of the system are described in this paper. An in vivo pressure monitoring case study is described as well.

QTc interval and QTc dispersion during haemodiafiltration.

BACKGROUND AND AIM: Our aim was to evaluate QTc interval and QTc dispersion in 27 end-stage renal disease (ESRD) patients undergoing Acetate Free Biofiltration (AFB) in order to ascertain any correlations between the electrrocardiographic (ECG) parameters, serum Na+, K+, Ca++, Mg++ and intraerythrocytic Mg++ (Mg++e) concentrations. All measures were made at t0 (session beginning), t1 (first hour), t2 (second hour), t3 (third hour), and t4 (session end). RESULTS: Blood pressure, heart rate, bodyweight and total ultrafiltration in the three dialysis sessions were constant. A significant progressive increase occurred in serum Ca++ during the sessions, while there was a significant diminution in serum K+. The pattern for Mg++ concentrations in serum and erythrocytes differed: in serum it decreased, whereas Mg++e increased. At t4, the QTc interval was reduced to a significant extent with respect to the baseline value. QTc dispersion significantly increased at t1 without there being significant variations at other times with respect to t0. At t2, t3 and t4, values promptly returned to baseline levels. QTc had a negative correlation with serum Ca++ levels at t4. In contrast, an inverse correlation was found between QTc dispersion and serum K+ at t1. No other correlations could be found between any other electrolytes, QTc interval or QTc dispersion. CONCLUSION: In conclusion, the decrease observed in the QTc interval at the end of an AFB session was inversely related to serum Ca++ concentrations. Moreover, an increase in QTc dispersion occurred during the first hour of the session, and was negatively correlated with serum K+.

Correlation between quality of life assessment and a personality neurobiologic model in dialyzed patients.

The Short Form 36 Health Survey (SF-36) is a self-administered scoring system that has been widely used and validated as a quality of life (QOL) assessment tool. In our study, a cluster analysis of SF-36 scores was performed in 50 healthy volunteers (controls) and 50 neurobiologically asymptomatic patients on maintenance hemodialysis (MHD). Firstly, we assayed the tendency to form clusters from each of the investigated dimensions. Statistic analysis was performed using the Student's t-test for independent measurements and multiple regression analysis. Secondly, we attempted to evaluate if the MHD to apply to both groups a general psychobiological personality model developed by Cloninger in 1987. Cloninger describes three independent personality dimensions: novelty seeking (NS), harm avoidance (HA)and reward dependence (RD). Each personality dimension would be the expression of hereditary variations integrating the three main brain systems, respectively: dopaminergic, serotoninergic and noradrenergic. Finally, we then aimed to investigate possible interferences among the seric concentrations of the neuromodulators and SF-36 scores, in the attempt to identify, using a simple approach, the complex personality structure of MHD patients. QOL self-assessment and seric neuromodulators were measured in both groups, choosing an interdialytic day for MHD patients. We found that MHD patients perceived a significant worsening in their QOL in all investigated dimensions with respect to the controls. In addition, they showed significantly lower dopamine and serotonine concentrations and significantly higher noradrenaline concentrations. Therefore, our study, confirmed data reported previously in the literature, that cluster analysis of SF-36 scores provides different results in the MHD population in comparison to normal subjects. In fact, comparing the hierarchical trees of both groups, it appeared evident that in MHD patients, cluster dimensions were greater than in the controls. In cluster compositions showed differences between the two groups. In fact, in MHD patients there were only a few of the clusters that were observed in the controls (mental health and social functioning, vitality and general health), while role-physical and role-emotional dimensions aligned outside the hierarchical tree, with a considerable linkage distance. In our opinion, it is fascinating that the three Cloninger neuromodulators could suggest that HD patient personalities are potentially cyclothymiac, altering the disposition of the two role functions inside the hierarchical tree.