[Simultaneous kidney and pancreas transplantation (SKPT) in patients with type 1 diabetes and chronic renal failure: experience in 12 patients in Chile]. / Trasplante simultáneo de páncreas y riñon en diabetes mellitus tipo 1: Experiencia de un centro en Chile.

BACKGROUND: Simultaneous kidney and pancreas transplantation (SKPT) is the best alternative for end stage renal disease among patients with insulin dependent diabetes mellitus. AIM: To report our experience with SKPT. MATERIAL AND METHODS: Retrospective analysis of 12 recipients of SKPT transplanted in one center starting in 1994, with a mean follow-up period of 6.8 years (2-15). RESULTS: Eleven of 12 recipients were in chronic hemodialysis before SKPT. Mean A, B, DR and HLA mismatch was 4.3. Mean preformed anti HLA antibodies was 3.3 %. Mean cold ischemia times for pancreas and kidney were 6 and 10 hours, respectively. In the first eight cases, the pancreas was drained to the bladder, and in the last four, an enteric drainage was performed. Eleven recipients were induced with antibodies, and maintenance immunosuppression consisted of cyclosporin or tacrolimus plus an antiproliferative agent. Ten year patient survival was 70%. Pancreas and kidney survival, defined by insulin and dialysis independence, were 72 and 73% respectively. Fifty percent of recipients experienced acute graft rejection (cellular or humoral), with good response to treatment except in one case. CONCLUSIONS: This experience shows that SKPT is associated with an excellent patient survival associated to insulin and dialysis independence in 70% of patients at 10 years.

Trasplante simultáneo de páncreas y riñon en diabetes mellitus tipo 1: Experiencia de un centro en Chile / Simultaneous kidney and pancreas transplantation (SKPT) in patients with type 1 diabetes and chronic renal failure: Experience in 12 patients in Chile

Background: Simultaneous kidney and páncreas transplantation (SKPT) is the best alternative for end stage renal disease among patients with insulin dependent diabetes mellitus. Aim: To report our experience with SKPT. Material andMethods: Retrospective analysis ofl2 recipients of SKPT transplanted in one center starting in 1994, with a meanfollow-upperiod of6.8years (2-15). Results: Eleven ofl2 recipients were in chronic hemodialysis before SKPT. Mean A, B, DR and HLA mismatch was 4.3. Mean preformed anti HLA antibodies was 3.3 percent. Mean cold ischemia times for páncreas and kidney were 6 and 10 hours, respectively. In the first eight cases, the páncreas was drained to the bladder, and in the last four, an enteric drainage was performed. Eleven recipients were induced with antibodies, and maintenance immunosuppression consisted ofCyclosporine or Tacrolimusplus an antiproliferative agent. Ten year patient survival was 70 percent. Páncreas and kidney survival, defined by insulin and dialysis independence, were 72 and 73 percent respectively. Fifty percent of recipients experienced acute graft rejection (cellular or humoral), with good response to treatment except in one case. Conclusions: This experience shows that SKPT is associated with an excellent patient survival associated to insulin and dialysis independence in 70 percent of patients at 10 years.

Glucagon-like peptide-1 is involved in sodium and water homeostasis in humans.

UNLABELLED: In previous studies with glucagon-like peptide-1 (GLP-1) we have observed that this peptide modulates fluid intake and increases renal sodium excretion in healthy volunteers and in patients with diabetes mellitus type 2. The effect of GLP-1 on thirst, water intake and on osmoregulation has, however, not been examined in detail in humans. METHODS: Seventeen healthy male subjects were enrolled in two double-blind, placebo-controlled studies. In study part A, 8 volunteers participated in a protocol with an intravenous salt load of 26.7 +/- 0.9 g comparing the effect of an infusion of GLP-1 (1.5 pmol/kg x min) to isotonic saline (placebo). Sodium excretion and water intake were measured. In part B, 9 volunteers were challenged with an oral salt load of 27.7 +/- 0.5 g; sodium excretion and water intake were determined comparing an infusion of GLP-1 (1.5 pmol/kg x min) to isotonic saline (placebo). In part C, intestinal biopsies along the gastrointestinal tract were obtained from 14 healthy subjects. Expression of human GLP-1 receptor mRNA was measured by real-time polymerase chain reaction. RESULTS: In study part A, an increase in renal sodium excretion was demonstrated: FeNa rose from 1.6 +/- 0.3 (placebo) to 2.7 +/- 0.2% (GLP-1; p = 0.0005). There was no difference in water consumption between the two treatments: 1,291 +/- 69 (saline) vs. 1,228 +/- 74 ml (GLP-1; p = 0.49). In part B, an oral salt challenge of 27.7 +/- 0.5 g led to an increased renal excretion of sodium during GLP-1: FeNa increased from 1.6 +/- 0.2% (placebo) to 2.0 +/- 0.2% (GLP-1; p = 0.012). In contrast to part A, oral water intake was reduced by 36% under GLP-1 treatment: 1,848 +/- 331 ml (placebo) vs. 1,181 +/- 177 ml (GLP-1; p = 0.0414). Three subjects in part B did not finish treatment with GLP-1 because of diarrhea. Human GLP-1 receptor mRNA expression was highest in the proximal human small intestine compared to terminal ileum and colon (p < 0.02). CONCLUSIONS: GLP-1 acts on renal tissue reducing sodium absorption, probably via similar sodium transporters, which also may be localized in the gastrointestinal tract. This hypothesis needs to be confirmed by further studies.

Effect of spironolactone on K(+) homeostasis and ENaC expression in lymphocytes from chronic hemodialysis patients.

BACKGROUND: Cardiac disease is the major cause of death in hemodialysis patients (HD). It is now clear that aldosterone has deleterious effects in the cardiovascular system. In the present study, we evaluated the effects of an aldosterone-antagonist, spironolactone, on the extrarenal regulation of potassium in HD patients. Furthermore, to validate the effectiveness of the spironolactone dose-design, we measured the expression of Na(+)-channel (ENaC alpha subunit) in peripheral blood mononuclear cells (PBMC), before and after a two-week course of spironolactone. METHODS: The study design included a two-week baseline period, followed by spironolactone treatment (50 mg three times weekly for 15 days), and by a two-week washout period and then a two-week placebo period. An oral K(+) load (0.3 mEq/K(+) kg body weight plus carbohydrates) was administered at the end of each period, and time-course of plasma potassium was evaluated. ENaC expression in PBMC was assessed before and after spironolactone. RESULTS: The maximal increase in plasma potassium after the K(+) carbohydrate load was: control 5.33 +/- 0.88 mEq K(+)/L; spironolactone 5.23 +/- 0.68 mEq K(+)/L; placebo 5.38 +/- 0.61 mEq K(+)/L (N= 9). No patients developed hyperkalemia during the spironolactone treatment period. ENaC expression was significantly higher in all six HD patients studied, compared to control subjects (P < 0.05). Treatment with spironolactone in HD patients reduced alpha subunit mRNA expression to values similar to those of normal subjects. CONCLUSION: Spironolactone may be considered for the treatment of selected chronic HD patients. The effect of the drug on a known target of aldosterone, the ENaC, demonstrates the effectiveness of the drug to block aldosterone effects in nonepithelial tissues.

Glucagon-like peptide 1 induces natriuresis in healthy subjects and in insulin-resistant obese men.

Glucagon-like peptide-1-(7-36)-amide (GLP-1) is involved in satiety control and glucose homeostasis. Animal studies suggest a physiological role for GLP-1 in water and salt homeostasis. This study's aim was to define the effects of GLP-1 on water and sodium excretion in both healthy and obese men. Fifteen healthy subjects and 16 obese men (mean body mass index, 36 kg/m2) were examined in a double-blind, placebo-controlled, crossover study to demonstrate the effects of a 3-h infusion of GLP-1 on urinary sodium excretion, urinary output, and the glomerular filtration rate after an i.v. 9.9-g salt load. Infusion of GLP-1 evoked a dose-dependent increase in urinary sodium excretion in healthy subjects (from 74 +/- 8 to 143 +/- 18 mmol/180 min, P = 0.0013). In obese men, there was a significant increase in urinary sodium excretion (from 59 to 96 mmol/180 min, P = 0.015), a decrease in urinary H+ secretion (from 1.1 to 0.3 pmol/180 min, P = 0.013), and a 6% decrease in the glomerular filtration rate (from 151 +/- 8 to 142 +/- 8 ml/min, P = 0.022). Intravenous infusions of GLP-1 enhance sodium excretion, reduce H+ secretion, and reduce glomerular hyperfiltration in obese men. These findings suggest an action at the proximal renal tubule and a potential renoprotective effect.

[Epidemiology of severe acute renal failure in Metropolitan Santiago]. / Epidemiología de la insuficiencia renal aguda grave. Un estudio prospectivo multicéntrico en la Región Metropolitana.

BACKGROUND: There is a paucity of information about the epidemiology of acute renal failure in Chile. AIM: To perform a prospective multicentric survey of severe acute renal failure in Chile. MATERIAL AND METHODS: All patients admitted to ten hospitals in Metropolitan Santiago, during a period of six months with severe acute renal failure, were studied. The criteria for severity was the requirement of renal replacement therapy. All patients information was gathered in special forms and the type of renal replacement therapy and evolution was registeres. RESULTS: One hundred fourteen patients were studied (65 males, age range 18 to 87 years). The calculated incidence of acute renal failure was 1.03 cases per 1000 hospital discharges. The onset was nosocomial in 79 subjects (69%) and community acquired in the rest. Renal failure was oliguric in 64 cases (56%) and in 60% of patients it had two or more causative factors. Sepsis, isolated or combined with other causes, was present in 51 of patients. Other causes included ischemia in 47%, surgery in 26%, exogenous toxicity in 25%, endocenous toxicity in 11%, acute glomerular damage in 6% and obstructive uropathy in 6%. Cardiac surgery was responsible for 47% of post operative cases of acute renal failure. Intermittent conventional hemodialysis, continuous renal replacement techniques and daily prolonged hemodialysis were used in 66%, 29% and 2% of patients, respectively. Overall mortality was 45% and it was higher in oliguric patients. Gender, age, cause or the type of therapy did not influence survival. Nine percent of surviving patients had some degree of kidney dysfunction at discharge. CONCLUSIONS: There is still a great space for prevention of severe acute renal failure in Chile, considering the main etiologies found in this study.

A simple method to calculate cyclosporine dosage to obtain a target C2 drug level.

C(2) Cyclosporine (CsA) level, as a surrogate of area under the time-concentration curve (AUC) 0-4 hours, is a good predictor of drug absorption and clinical outcome after kidney transplantation. It has been difficult to define the optimal C(2) level in the individual case and given the broad range of C(2) due to interindividual absorption variability it has been troublesome to determine the drug dose needed to obtain an expected C(2)-CsA concentration. In this study data of 16 stable renal and renal/pancreas recipients treated with prednisone, azathioprine, and CsA (Neoral) managed by C(0) level was examined. CsA concentrations at time 0 (basal), 2, 6, and 12 hours post CsA (Neoral) intake were determined the day of the study. A significant linear regression level was established between C(2) (but not C(0), C(6) and C(12)) and the dosage expressed as mg/kg/d (P = 0.0113, correlation coefficient r = 0.573018). Subsequently, another 27 renal transplant recipients were studied retrospectively and divided into three groups according to posttransplant period: 1 to 6, 7 to 12, and beyond 12 months after transplant. Equations derived from the relationship between C(2) and dose (mg/kg/d) were similar between the three groups and when compared with the first study. A formula obtained from the 27 patients in the whole posttransplant period (mg/kg/d = C(2) x 0.0010208 + 1.86125) was applied to patients of the first study obtaining a regression coefficient between actual and calculated CsA dose of 0.6145 (P = 0.01). A more accurate equation (P = 0.0001, r = 0.5925) was obtained by analyzing 145 C(2) determinations covering a period from 1 month to 8 years following transplant which gave a linear regression line defined by the equation C(2) x 0.001473 + 1.6673. This equation would permit the calculation mg/kg/d of CsA (Neoral) dose to obtain an expected C(2) level. The derived equation shown in this paper has a predictive value of 50% to 60% only, but can help to find adequate dosage in the presence of an inappropriate C(2) level.

[Epidemiology of hypertension in chronic hemodialysis]. / Epidemiología de la hipertensión en hemodiálisis crónica.

BACKGROUND: Hypertension is a common and important cardiovascular risk factor in patients on chronic hemodialysis. AIM: To report the prevalence and characteristics of hypertension among patients on chronic hemodialysis. PATIENTS AND METHODS: Cross sectional study of 313 patients (192 male, aged 57 +/- 18 years) dialyzed in 7 representative centers in Santiago, Chile. RESULTS: Patients were on hemodialysis for a mean of 68 +/- 53 months and 67 (21%) were diabetic. 230 (74%) were hypertensive and 223 of these (97%) had predialysis hypertension. A multivariate analysis showed that hypertension was associated with increased weight gain between dialysis, failure to achieve the postdialysis dry weight, increasing age and the presence of diabetes. Among hypertensive patients, 61% were receiving antihypertensive medications, compared with 27% of patients with normal blood pressure. CONCLUSIONS: High blood pressure is highly prevalent among patients on chronic hemodialysis and is associated to hypervolemia, age and the presence of diabetes.

Estimating phosphate removal in haemodialysis: an additional tool to quantify dialysis dose.

BACKGROUND: Half of the dialysis population suffers from hyperphosphataemia, which is now recognized as a major factor of haemodialysis (HD) morbidity and mortality. Current control is focussed on reducing dietary phosphate intake and diminishing absorption using phosphate binders, whereas control and quantification of phosphate removal by HD is undervalued. The aim of this prospective study was to develop a simple, bedside formula to estimate dialytic phosphate removal in stable HD patients. METHODS: This was a prospective, randomized trial. Phosphate and urea elimination were assessed in a representative group of patients at two dialysis centres using randomly different dialysers (1.3-2.4 m(2)). Quantification was performed by partial dialysate collection, concentration measurements in blood and effluent dialysate spot samples, and Kt/V(urea) during standard high-flux HD. Multiple linear regression analyses were used in 77% of all data sets to generate an equation to predict phosphate removal. The formula was validated in the remaining 23% of data sets, in the same group of patients using a large capillary filter, and in diabetic patients treated with a small dialyser at different blood flows (200, 250, and 300 ml/min). RESULTS: A formula allowing quantification of phosphate removal within one HD session was developed in 18 of 74 patients during 41 treatments (137 out of 177 data sets) and was determined as: M(PO4pred)=0.1t -17+50c(ds60)+11c(b60), where t is treatment time in min, c(ds60) and c(b60) are phosphate concentrations in dialysate and plasma measured 60 min into HD in mmol/l, and M(PO4pred) is estimated phosphate removed in mmol. The precision was remarkable (r(2)=0.92-0.94). The comparison of phosphate and Kt/V(urea) showed a significant association (r(2)=0.28), albeit with remarkable scatter. CONCLUSIONS: We present the first approach to quantify phosphate removal during high-flux HD by a bedside formula. Only 28% of the variation in phosphate removal was explained by Kt/V(urea). It appears that other factors not adequately accounted for by Kt/V(urea) affect phosphate removal. Therefore, we propose an individual control and quantification of phosphate removal in HD.