Campylobacter fetus peritonitis and bacteremia in a patient undergoing continuous ambulatory peritoneal dialysis.

We report a case of Campylobacter fetus peritonitis and bacteremia in a patient undergoing continuous ambulatory peritoneal dialysis.

Are low concentrations of serum triiodothyronine a good marker for long-term mortality in hemodialysis patients?

INTRODUCTION: Low serum free triiodothyronine (FT3) concentrations have been reported in a high percentage of chronic renal failure patients and have been considered as an independent predictor of mortality in dialysis patients. OBJECTIVE: Our aim has been to evaluate the prognostic value of FT3 levels for long-term mortality in stable hemodialysis patients surviving at least 12 months. PATIENTS AND MEASUREMENTS: We retrospectively analyzed 89 stable hemodialysis patients (50 males; mean age 67.9 +/- 11.8 years). All patients had a baseline clinical and analytical evaluation. We analyzed the relationship between baseline FT3 and mortality by means of survival analysis (Kaplan-Meier) and Cox regression analysis. RESULTS: Mean values of thyroid function test were: thyrotropin (TSH) 2.02 +/- 1.5 microU/ml, free thyroxine (FT4) 1.26 +/- 0.23 ng/dl, and FT3 2.7 +/- 0.4 pg/ml. During a median follow-up time of 33.6 +/- 14.9 (12 - 62) months, 41 patients died. FT3 was similar in patients who died or survived (2.6 +/- 0.5 vs. 2.7 +/- 0.4 pg/ml ns). Kaplan-Meier analysis did not show significant differences in mean survival according to tertiles of FT3. In multivariate Cox regression analysis, FT3 was not a predictor of mortality (RR 0,001; 95% CI; 0.000 to 1.73). CONCLUSIONS: These data suggest that low FT3 levels are not predictive for mortality in a subgroup of stable HD patients who could survive more than 12 months.

[Role played by peritoneal dialysis in treating refractory heart failure]. / Papel de la diálisis peritoneal en el tratamiento de la insuficiencia cardíaca refractaria.

Associated renal and cardiac diseases have a high prevalence among the population in several clinical contexts: acute renal failure in the context of decompensated heart failure (HF), HF patients who develop chronic kidney disease (CKD) and patients with CKD who develop HF. In recent years, cardiorenal syndrome has been described as deteriorating kidney function in the context of HF. However, there are other clinical situations for which nephrologists can contribute their knowledge as a part of an integral treatment strategy, as is the case with refractory HF (RHF). All of these situations require an interdisciplinary cooperative effort between cardiologists and nephrologists with the aim of providing integral treatment. This article aims to review the role of the nephrologist in HF treatment, with an emphasis on the subgroup of patients with RHF and current evidence regarding the usefulness of peritoneal dialysis (PD) as a chronic coadjuvant treatment.

[Approach to quality objectives in incidents of patients in peritoneal dialysis]. / Cumplimiento de objetivos de calidad y evolución de los pacientes incidentes en diálisis peritoneal.

INTRODUCTION: In 2007 the Scientific Quality-technical and Improvement of Quality in Peritoneal Dialysis was edited. It includes several quality indicators. As far as we know, only some groups of work had evaluated these indicators, with inconclusive results. AIM: To study the evolution and impact of guidelines in Peritoneal Dialysis. METHODS: Prospective cohort study of each incident of patients in Peritoneal Dialysis, in a regional public health care system (2003-2006). We prospectively collected baseline clinical and analytical data, technical efficacy, cardiovascular risk, events and deaths, hospital admissions and also prescription data was collected every 6 months. RESULTS: Over a period of 3 years, 490 patients (53.58 years of age; 61.6% males.) Causes of ERC: glomerular 25.5%, diabetes 16%, vascular 12.4%, and interstitial 13.3%. 26.48% were on the list for transplant. Dialysis efficacy: Of the first available results, the residual renal function was 6.37 ml/min, achieving 67.6% of all the objectives K/DOQI. 38.6% remained within the range during the entire first year. Anaemia: 79.3% received erythropoietic stimulating agents and maintained an average Hb of 12.1 g/dl. The percentage of patients in the range (Hb: 11-13 g/dl) improved after a year (58.4% vs 56.3% keeping in the range during this time of 25.6%). Evolution: it has been estimated that per patient-year the risk of: 1) mortality is 0.06 IC 95% [0.04-0.08]; 2) admissions 0.65 [0.58-0.72]; 3) peritoneal infections 0.5 [0.44-0.56]. CONCLUSION: Diabetes Mellitus patients had a higher cardiovascular risk and prevalence of events. The degrees of control during the follow-up in many topics of peritoneal dialysis improve each year; however they are far from the recommended guidelines, especially if they are evaluated throughout the whole study.

Short daily versus conventional hemodialysis quality of life: a cross-sectional multicentric study in Spain.

BACKGROUND: End-stage renal disease is a major health problem worldwide nowadays. Although conventional hemodialysis is the most widely used modality, short daily hemodialysis has been proposed as a more physiologic treatment. The objective of this article is to compare the quality of life of patients on each hemodialysis modality. METHODS: A multicentric cross-sectional study was performed in 9 Spanish hospitals. Patients treated for at least 3 months with conventional or short daily hemodialysis were included and quality of life measured using the Euroqol-5D quality of life questionnaire. Bayesian models were used for analyzing quality of life results. RESULTS: Ninety-three patients were included, 27 were on daily hemodialysis and 66 on conventional hemodialysis. All models demonstrated a better quality of life for daily hemodialysis versus conventional hemodialysis. Only 14% of the patients on conventional hemodialysis were willing to change to a daily schedule. CONCLUSIONS: Short daily hemodialysis shows a better quality of life than conventional hemodialysis with all Bayesian approaches considered.

[Changing the frequency of administration of darbepoetin alfa (from weekly to fortnightly) maintains the haemoglobin levels in patients undergoing peritoneal dialysis]. / El cambio en la frecuencia de administración de darbepoetin alfa (de semanal a quincenal) mantiene los niveles de hemoglobina en pacientes en diálisis peritoneal.

SUMMARY BACKGROUND: Less frequent dosing regimens during anemia treatment could benefit Peritoneal Dialysis (PD) patients. We investigated the effectiveness of darbepoetin alfa dosed every-other-week (Q2W) for maintaining hemoglobin (Hb) levels (11-13 g/dL). PATIENTS AND METHODS: One hundred and nine PD patients from 14 centers participated in an 8-month observational, prospective study. Patients (Hb 11-13 g/dL) receiving weekly (QW) darbepoetin alfa switched to Q2W dosing at the investigator's discretion. Doses were adjusted according to published guidelines. RESULTS: Sixty-nine percent (75 out of 109) of patients switched to Q2W dosing. Thirty-three percent maintained the g/week, equivalent to twice the previous mean weekly dose (26.1-25.8 g/week, QW dose). Forty-seven percent received a dose reduction (35.8-20.2 equivalent to the previous QW dose). More patients in the maintenance dose group 11 g/dL than those receiving a reduced weekly dose (80% vs. had Hb levels 51.4%, respectively, p = 0.0236). During the Q2W phase, the mean Hb level ranged from 12.0-12.5 g/dL for the maintenance dose group and 11.5-12.0 g/dL for the reduced dose group. From the switch to the end of the study, the mean (SD) change in Hb was -0.7 g/dL (0.98 g/dL, p = 0.0557) and -0.6 g/dL (1.6 g/dL, p = 0.1296) for the maintenance and reduced dose groups, respectively. The Q2W darbepoetin alfa was well tolerated. Only a single treatment-related adverse event (polycythemia) occurred. CONCLUSION: The majority of PD patients receiving QW darbepoetin alfa can be effectively switched to Q2W and still maintain their Hb level.

[Effect of using icodextrin as a starting therapy for peritoneal permeability]. / Efecto del uso de icodextrina de inicio sobre la permeabilidad peritoneal.

UNLABELLED: Peritoneal permeability differs between patients at the time of starting peritoneal dialysis (PD) and it can increase along with time on the technique. This fact is related to peritonitis, the biocompatibility of the dialysis fluids and the use of glucose as osmotic agent. The aim of the present study was to evaluate if the use of one exchange a day of icodextrine from the time of DP initiation affects the evolution of peritoneal permeability. PATIENTS AND METHODS: 56 patients starting PD (mean age: 48.3 +/- 14.0; 62.5% males; 17.9% diabetics) that used one exchange a day with icodextrine from the time of starting PD. We performed a peritoneal transport kinetic study at the time of starting PD and then every 6 months during two years. We calculated the peritoneal mass transfer area coefficient of creatinine (Cr-MTAC) and urea (U-MTAC) as well as the D/P creatinine relationship (D/P Cr). As a control group we used the results of Cr-MTC of 249 patients that had used glucose as the only osmotic agent from the time of starting PD. RESULTS: The peritoneal transport, calculated using Cr-MTC, U-MTC and D/P Cr, diminished at 12 months (11.7+/-5.7 vs. 8.1+/-3.1; 23.5+/-7.3 vs. 18.9+/-3.8; 0.72+/-0.09 vs. 0.67+/-0.08; respectively), staying stable afterwards.We found that high transporters (HA) patients (higher quatril Cr-MTC ) showed a higher diminution of Cr-MTAC along the first year of treatment. The diminution of Cr-MTAC after 12 months using icodextrine was significantly higher (p<0.001) that the one observed in the control group that only used glucose as osmotic agent (10.5+/-5.3 vs. 10.1+/-4.6). We found that high transporters (HA) patients (higher quatril Cr-MTC) showed a higher decrease of Cr-MTAC along the first year of treatment. CONCLUSION: the use of icodextrine at the time of starting PD might help to correct the high transport status observed in some patients during the first months of treatment. The peritoneal transport kinetic studies performed at 6 and 12 months after starting PD are more representative of the long term peritoneal transport characteristics of the patients than those performed at the time of starting PD.

Epithelial-to-mesenchymal transition of mesothelial cells is an early event during peritoneal dialysis and is associated with high peritoneal transport.

Ultrafiltration (UF) failure is a consequence of long-term peritoneal dialysis (PD). Fibrosis, angiogenesis, and vasculopathy are causes of this functional disorder after 3-8 years on PD. Epithelial-to-mesenchymal transition (EMT) of mesothelial cell (MC) is a key process leading to peritoneal fibrosis with functional deterioration. Our purpose was to study the peritoneal anatomical changes during the first months on PD, and to correlate them with peritoneal functional parameters. We studied 35 stable PD patients for up to 2 years on PD, with a mean age of 45.3+/-14.5 years. Seventy-four percent of patients presented loss of the mesothelial layer, 46% fibrosis (>150 microm) and 17% in situ evidence of EMT (submesothelial cytokeratin staining), which increased over time. All patients with EMT showed myofibroblasts, while only 36% of patients without EMT had myofibroblasts. The number of peritoneal vessels did not vary when we compared different times on PD. Vasculopathy was present in 17% of the samples. Functional studies were used to define the peritoneal transport status. Patients in the highest quartile of mass transfer area coefficient of creatinine (Cr-MTAC) (>11.8 ml min(-1)) showed significantly higher EMT prevalence (P=0.016) but similar number of peritoneal vessels. In the multivariate analysis, the highest quartile of Cr-MTAC remained as an independent factor predicting the presence of EMT (odds ratio 12.4; confidence interval: 1.6-92; P=0.013) after adjusting for fibrosis (P=0.018). We concluded that, during the first 2 PD years, EMT of MCs is a frequent morphological change in the peritoneal membrane. High solute transport status is associated with its presence but not with increased number of peritoneal vessels.

[Anatomic-functional correlation of the peritoneal membrane]. / Correlación anátomo-funcional de la membrana peritoneal.

Ultrafiltration failure is the most frequent alteration of peritoneal transport in peritoneal dialysis (PD) patients, and is a frequent cause of technical withdrawal. At the beginning of the therapy, there is a great functional diversity, but alter the third or fourth years the 20% of patients develop progressive ultrafiltration failure and an increase of the small solute transport. In parallel to this functional alteration, the peritoneum of PD patients shows morphological alterations, such as loss or transformation of mesothelial cells, basal membrane reduplication, submesothelial fibrosis, hyalinazing vasculopathy and neoangiogenesis. There are scant comparative studies of morphofunctional correlation. Most of them have been reported on long-term PD patients and showed a progressive increase of fibrosis and vasculopathy with time on PD, specially in patients with ultrafiltration failure and in those with sclerosing peritonitis. The peritoneal vessel number do not always increase with time on PD, and it is associated with advanced ultrafiltration failure. Some short-term studies have demonstrated that the initial lesion related to the high small solute peritoneal transport is the epithelial to mesenchimal transition of the mesothelial cell (the transformation of mesothelial cell into fibroblastic cell). The higher secretion of extracellular matrix and vascular endothelial growth factor by the transformed mesothelial cells should participated on later development of fibrosis and high peritoneal permeability, not always in relation with higher number of peritoneal vessels.

[New peritoneal dialysis solutions and their combinations]. / Nuevas soluciones de diálisis peritoneal y sus combinaciones.

Peritoneal dialysis (PD) treatment has been related to functional and structural changes in peritoneum. The biocompatibility of the PD fluids is one of the most important factors related to this complication. New solutions for PD have been developed in an effort to reduce the bioincompatibility of conventional glucose containing, lactate-buffered solutions, and thereby to improve the clinical outcomes of PD. The use of new manufacturing techniques, buffer presentation, and new osmotic alternatives to glucose (amino acids, icodextrin) have allowed potentially improved peritoneal survival (in terms of structure and function) and improved subjective patient experience. Additional benefits have also included enhanced management of salt and water removal, supported nutritional status and improvement in the systemic metabolic derangements associated with conventional PD treatment, based on glucose-containing lactate-buffered solutions. In vitro and in vivo studies have shown the biocompatibility of these new solutions to be superior to that of standard solutions. This review summarized the characteristics of the next generation of PD fluids currently available and analyzed the potential benefits related to the combination of the different elements.

[Theoretical bases for the proposal of a randomized, controlled, open label clinical trial to assess the efficacy of adding bemiparin to the icodextrin solution in patients on peritoneal dialysis with peritoneal transport disorders [FRIAT-BEM-2005-01]]. / Bases teóricas para la propuesta de un ensayo clínico aleatorizado, controlado y abierto, para evaluar la eficacia de la adición de bemiparina a la solución de icodextrina en pacientes en diálisis peritoneal con trastornos del transporte peritoneal [FRIAT-BEM-2005-01].

Multiple investigations performed on peritoneal pathophysiology during peritoneal dialysis (PD) suggest that intraperitoneal heparin might modify most of the causes of membrane deterioration. The actions described favouring this idea are: 1) Peritoneal Chronic inflammation alters peritoneal function and hepraine has anti-inflammatory properties. 2) Peritoneal fibrosis related to peritoneal dialysis or traumatic injury may be avoided or limited with heparin. 3) Heparine induces tPA synthesis by mesothelial cells, which represents a potentiation of fibrinolytic action. 4) Heparine, specifically low-molecular weight heparin, inhibits angiogenesis. 5) Intraperitoneal heparin favors the removal of advanced glycosilation end products in PD. 6) Animal models and clinical studies with small series of patients have demonstrated an improvement of peritoneal function with intraperitoneal heparine use. 7) Until now, no adverse effects of the intraperitoneal heparin use have been found. In consequence, it is a plausible hypothesis to consider that intraperitoneal heparin may favourably modify peritoneal function in patients under peritoneal dialysis.

[Pasteurella multocida and Candida albicans peritonitis]. / Peritonitis por pasteurella multocida y Candida albicans.

Peritonitis is a well-known complication of peritoneal dialysis (PD) treatment. Repetitive episodes may induce an irreversible damage of the peritoneal membrane and are a frequent cause of PD drop-out. The great majority of the episodes are due to Staphylococci, Streptococci or gram- negative organisms. Unusual organisms have been reported, specially in immunosuppressed hosts. Few cases of Pasteurella Multocida (PM) have been described in PD patients. To our knowledge, we describe the first case preceding a Candida Albicans (CA) peritonitis. A review of the literature of PM peritonitis and the relation between these two microorganisms is discussed.

[Guidelines of the Spanish Society of Nephrology. Clinical practice guidelines for peritoneal dialysis]. / Guías Sociedad Española de Nefrología. Guías de práctica clínica en diálisis peritoneal.

In Spain and in each of its autonomous communities, the dialysis treatment of chronic renal disease stage 5 is totally covered by public health. Peritoneal dialysis, in any of its modalities, is established as the preferred home dialysis technique and is chosen by high percentage of patients as their choice in dialysis treatment. The Spanish Society of Nephrology has promoted a project of creation of performance guides in the field of peritoneal dialysis, entrusting a work group composed of members of the Spanish Society of Nephrology a with the development of these guides. The information offered is based on levels of evidence, opinion and clinical experience of the most relevant publications of the topic. In these guides, after defining the concept of << peritoneal dialysis>>, the obligations and responsibilities of the sanitation team of the peritoneal dialysis unit are determined, and protocols and performance procedures that try to include all the aspects that concern the patient with chronic renal disease in substitute treatment with this technique are developed. They propose prescription objectives based on available clinical evidence and, lacking this, on the consensus of the experts' opinions. The final aim is to improve the care and quality of the of the patient in peritoneal dialysis, optimizing in this way the survival of the patient and of the technique. In Spain, as in other neighbouring countries, peritoneal dialysis has an incidence and prevalence that is much lower than that of hemodialysis, ranging in the last evaluation by the Spanish Society of Nephrology between 5 and 24% in the different autonomous communities. The great majority of peritoneal dialysis units form part of the public network of the Spanish state, with special representation as a Satellite Unit or Concerted Center related to the public hospital of reference, on which it must depend.

Tissue models of peritoneal fibrosis.

OBJECTIVE: To evaluate the utility of peritoneal pathologic samples, unrelated to peritoneal dialysis (PD) treatment, for the study of peritoneal fibrosis and inflammation. METHODS: Comparative morphologic and immunohistochemical study of peritoneal pathologic samples unrelated to PD with peritoneal biopsies from PD patients with special emphasis on the expression of myofibroblastic and epithelial-to-mesenchymal transition markers. RESULTS: Regarding morphology, PD-related simple fibrosis was less cellular, with greater stromal hyalinization, determining a homogeneous, hypocellular aspect of the submesothelium. In contrast, non-PD fibrosis was more cellular with an extracellular matrix showing a dense and fibrillar quality with wide bundles of collagen. Hylinazing vasculopathy was only present in PD samples. Myofibroblastic differentiation and epithelial-to-mesenchymal transition were common findings in all situations of peritoneal fibrosis. Calponin and calretinin are useful cellular markers to study such fibrogenic mechanisms and correlate with other well-known markers such as a -SMA and cytokeratins. Their expression was much more intense in those samples showing acute inflammation (peritonitis). CONCLUSIONS: Non-PD models of peritoneal fibrosis seem very useful to evaluate important features of human peritoneal pathology such us fibrogenesis, and inflammation. Fibrogenic events such as myofibroblastic differentiation and epithelial-to-mesenchymal transition are evident in these tissue samples allowing us to use them as an accessible source for in vivo and ex vivo studies. Both events show their maximal expression in situations of acute inflammation supporting the important role that peritonitis episodes play in the progression of fibrosis.

Myofibroblastic differentiation in simple peritoneal sclerosis.

OBJECTIVE: To analyze the presence of myofibroblasts in a series of peritoneal dialysis (PD) patients with simple sclerosis and non-PD, uremic patients. Since there is a close correlation between active fibrosis and myofibroblastic differentiation we wanted to test if myofibroblasts are present in uremic, non-PD peritoneal samples. To determine if there are correlations between myofibroblastic presence and other functional and morphologic peritoneal parameters. METHODS: Biopsies were collected from three patient groups: 1) Normal control samples (n = 15) of parietal and visceral peritoneum 2) non-PD uremic patients (n = 16); and 3) uremic patients on PD (n = 32). Peritoneal morphologic and functional parameters and immunohistochemical expression of alfa-smooth muscle actin was analyzed in each case. Vascular endothelial growth factor (VEGF), bcl-2 anti-apoptotic protein, and progesterone receptor was evaluated in a subset of cases. RESULTS: Myofibroblasts were present in 56.3% of the patients with PD-related simple sclerosis. In most cases they were distributed in the upper submesothelial area. None of the biopsies from normal controls and uremic, non-PD patients showed myofibroblasts. Within the group of PD patients, myofibroblasts showed no correlation with time on dialysis, urea/creatinine MTAC, episodes of peritonitis, submesothelial thickening, hyalinizing vasculopathy or mesothelial status. In a subset of PD patients VEGF expression was observed in submesothelial fibroblastic cells. No expression of progesterone receptor or bcl-2 was observed. CONCLUSIONS: Myofibroblasts are a reliable and simple indicator of fibrosis since they appear in early stages of PD treatment and in patients with minor morphologic anomalies. They are not exclusive of patients with sclerosing peritonitis, ultrafiltration loss or long standing treatment. Their absence in non-PD, uremic patients suggest that uremia-related fibrosis takes place without a significant participation of myofibroblasts.

Effects of rapamycin on the epithelial-to-mesenchymal transition of human peritoneal mesothelial cells.

The preservation of the peritoneal membrane is crucial for long-term survival in peritoneal dialysis. Epithelial-to-mesenchymal transition (EMT) is a process demonstrated in mesothelial cells (MC), responsible for negative peritoneal changes and directly related to PD. EMT enables neovascularization and fibrogenic capabilities in MC. Vascular endothelial growth factor (VEGF) is the mediator for neo-vascularization. Rapamycin is a potent immunosuppressor with antifibrotic action in renal allografts and has a demonstrated anti-VEGF effect. We performed this study with the hypothesis that rapamycin may regulate the EMT of MC. MC from human omentum were cultured. When mesothelial cells reached confluence, some of them were stimulated with r-TGF-beta (1 ng/mL) to induce EMT, co-administered with rapamycin (0.2, 2, 4, 20 and 40 nM). Other groups of cells received similar doses of rapamycin or r-TGF-beta, separately. Cells were analyzed at 6, 24, 48 hours and 7 days. As markers of EMT we included alfa -SMA, E-cadherin and snail nuclear factor by quantitative RT-PCR. EMT markers and regulators demonstrated the following changes with rapamycin: E-cadherin (a protective gene for EMT) increased 2.5-fold relative to controls under 40 nM, at 24h. Importantly, rapamycin inhibited snail expression induced by TGF-beta at 6h, whereas TGF-beta increased snail 10-fold. At day 7, rapamycin showed no anti-EMT properties. An important decrease in alfa -SMA expression by MC after rapamycin addition was observed. In conclusion, rapamycin shows a mild protective effect on EMT, as it increases E-cadherin and decreases alfa -SMA expression. Consequently, rapamycin might partially regulate the epithelial-to-mesenchymal transition of mesothelial cells.

Cultures of human osteoblastic cells from dialysis patients: influence of bone turnover rate on in vitro selection of interleukin-6 and osteoblastic cell makers.

The factors contributing to renal osteodystrophy are still incompletely characterized. A variety of cytokines and growth factors appear to have ill-defined roles in this disease. Our aim is to compare osteoblastic cell growth and different osteoblastic markers in vitro with histomorphometric bone parameters and some serum bone-turnover markers in vivo in dialysis patients with either high- (HTBD) or low-turnover (LTBD) bone disease. Six patients were diagnosed to have LTBD, and another five patients, HTBD. Intact parathyroid hormone (PTH) and osteocalcin (OC) levels in serum were greater in patients with HTBD than in those with LTBD. Osteoblastic cells isolated from iliac crest biopsy specimens were grown in culture medium for different times up to 13 days. Osteoblastic cell growth (cell number and area under the cell growth curve) was greater in patients with HTBD than in those with LTBD. Static and dynamic bone formation parameters correlated with serum PTH levels. No correlation was found between PTH and osteoblastic cell proliferation. OC, C-terminal type I procollagen, and alkaline phosphatase osteoblastic secretion in vitro were similar in the HTBD and LTBD groups. However, interleukin-6 (IL-6) secretion was greater in cells isolated from patients with LTBD. Our results indicate that osteoblastic cell growth and osteoblastic IL-6 secretion are related to bone turnover in patients with osteodystrophy. Our findings support the hypothesis that factors other than PTH level might have an important role in affecting osteoblastic function in renal osteodystrophy.

Long-term effects of recombinant human erythropoietin therapy on growth hormone secretion in uremic patients undergoing peritoneal dialysis.

Recombinant human erythropoietin (rhEPO) is being successfully used for the treatment of uremic anemia. Short-term studies have proved that correction of anemia with rhEPO therapy is accompanied by several changes in growth hormone (GH) secretion in uremic patients. The present study aimed to assess the influence of long-term rhEPO therapy on baseline and stimulated GH concentrations in a group of uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Seven well-nourished and clinically stable CAPD patients were studied. Ten normal subjects were studied as controls. GH responses to direct pituitary stimulation with GH-releasing hormone (GHRH) (100 microg intravenously [i.v.]) and indirect hypothalamic stimulation with insulin-induced hypoglycemia (0.1 U/kg body weight i.v.) and clonidine (0.15 mg/m2 orally), were assessed before and after 3, 6, and 12 months of subcutaneously administered rhEPO therapy. After rhEPO administration, an increase of the hemoglobin concentration was observed in all patients and maintained at about 12 g/dL throughout the study period. rhEPO therapy did not induce any significant change in baseline concentrations of GH and insulin-like growth factor I. Correction of the anemia was accompanied by a clear increase in the area under the curve (AUC) and the area above the baseline (AAB) of GH secretion in response to GHRH stimulation. These changes were statistically significant after 3 and 6 months of therapy, although at 12 months no significant differences in relation to pretreatment values could be observed. rhEPO treatment was associated with a progressive decrement in the GH AUC and AAB in response to hypoglycemic challenge, reaching statistically significant values at months 6 and 12. On the other hand, compared with the control group, GH responses to clonidine were blunted at the start of the study in CAPD patients, and rhEPO therapy was not accompanied by any modification. In conclusion, long-term treatment with rhEPO in CAPD patients is associated with complex and profound effects on somatotrope cell function, characterized by diverse effects on GH responses to stimuli that release GH through different mechanisms. Some of these rhEPO-induced alterations in somatotrope function are dependent on the duration of treatment.

Vascular endothelial growth factor (VEGF) levels in peritoneal dialysis effluent.

BACKGROUND: Long-term peritoneal dialysis (PD) patients who develop peritoneal ultrafiltration failure have an abnormally large number of capillaries and sclerotic changes in peritoneal biopsy. Peritoneal vascular endothelial growth factor (VEGF) production has been suggested to explain the higher levels in peritoneal effluent than in plasma. The high effluent VEGF levels have been related to peritoneal changes consisting of increased permeability to small molecules. To further analyze the relationship between peritoneal neoangiogenesis induced by VEGF and peritoneal transport, we studied peritoneal effluent VEGF levels in active PD patients. METHODS: VEGF levels were determined in serum and plasma, and in peritoneal effluent (PE) after 4, 8 and 15 h dwell times. RESULTS: PE VEGF levels were 58.6+/-33.7 pg/mL, with a mean VEGF D/P ratio of 0.45+/-0.29 (range 0.06-0.93). In low-transport patients (n = 7) this ratio did not differ from high-average ones (n=5) (0.48+/-0.3 and 0.41+/-0.1, NS). In multivariate analysis, the VEGF D/P ratio showed no correlation with the independent variables included in this study. VEGF levels were higher in 15 h than in 8 h effluent; so the VEGF D/P ratios were higher as well. Regression analysis showed a direct correlation between PEVEGF levels and dwell time (r: 0.57, p = 0.03), but not between VEGF D/P ratio and dwell time. PEVEGF levels directly correlated with effluent protein content. Regression analysis showed no correlation between PEVEGF levels and age, time on PD, days of peritonitis, urea and creatinine-mass transfer coefficients, ultrafiltration capacity, and accumulated glucose dose. Multivariate regression analysis showed correlation only between PEVEGF levels and dwell time, but not with the other independent variables. CONCLUSIONS: This study confirms that VEGF is present in fresh PE from PD patients at levels that suggest local production and filtration from plasma. Peritoneal effluent VEGF levels are not significantly associated with peritoneal functional parameters and background, and seem to be influenced by ultrafiltration in a dilution process. We believe that the role of VEGF in peritoneal pathophysiology is part of a complex relationship involving multiple peritoneal structures and other growth factors, including local counteracting factors for VEGF that regulate neoangiogenesis.