Attilio Elli

Abnormal red-cell calcium pump in patients with idiopathic hypercalciuria.

Idiopathic hypercalciuria is a common disorder whose inheritance suggests an enzyme abnormality in calcium transport. We measured calcium-magnesium-ATPase activity in erythrocytes from 38 patients (mean age [+/- SEM], 40 +/- 2.1 years) with idiopathic hypercalciuria (24-hour urinary calcium excretion greater than or equal to 0.1 mmol per kilogram of body weight) and a history of multiple calcium oxalate kidney stones. As compared with 41 healthy controls, the patients with hypercalciuria had increased erythrocyte-membrane calcium-magnesium-ATPase activity (64.2 +/- 2.19 vs. 51.6 +/- 1.91 nmol of ATP split per milligram per minute; P less than 0.01) and increased sodium-potassium pump activity (6866 +/- 233 vs. 6096 +/- 228 mumol of sodium per liter of red cells per hour; P less than 0.05). No significant difference between the two groups was found in erythrocyte sodium-potassium cotransport, sodium-lithium countertransport, or potassium content. In 66 patients with kidney stones (38 with hypercalciuria and 28 with normal calcium excretion), 24-hour urinary calcium excretion correlated with calcium-magnesium-ATPase activity (r = 0.46, P less than 0.001). Erythrocyte calcium-magnesium-ATPase activity remained unchanged in eight subjects studied after four months on a low-calcium diet. A study of 30 healthy families found significant correlations between mean values in parents and those in offspring for calcium-magnesium-ATPase (r = 0.68, P less than 0.001) and urinary calcium excretion (r = 0.45, P less than 0.02), with no significant correlations between parents with respect to these measures (r = 0.27 and r = 0.08, respectively). We conclude that abnormalities in erythrocyte calcium-magnesium-ATPase activity may represent an inherited defect in calcium transport related to the cause of idiopathic hypercalciuria.

Long-term results with cyclosporine monotherapy in renal transplant patients: A multivariate analysis of risk factors

There is little information on the long-term outcome of patients initially assigned to cyclosporine (CsA) monotherapy and requiring the addition of steroid therapy during follow-up. The aim of this report is to describe our experience with 143 first renal transplant recipients (120 cadaver transplants, 23 living donor transplants) randomized to receive CsA monotherapy as a treatment arm of three consecutive controlled clinical trials. Median follow-up was 86 months. Thirty-four percent of the patients remained on the original CsA monotherapy, whereas the remaining 66% required the addition of steroid therapy. Cumulative patient and graft survivals at 11 years were 0.89 (95% confidence interval [CI], 0.83 to 0.95) and 0.62 (95% CI, 0.52 to 0.72), respectively. The 11-year graft survival for converted patients was 0.53 (95% CI, 0.39 to 0.67). Cumulative graft half-life was 19.9 +/- 3.47 (SE) years. According to the Cox model, variables at transplantation that correlated with a lower 11-year graft survival were yearly increases in age (relative risk [RR], 1. 04; P = 0.039), monthly increases in hemodialysis duration (RR, 1.01; P = 0.029), no blood transfusion before transplantation (RR, 1.99; P = 0.043), CsA administration in a double daily dose (RR, 2.35; P = 0.008), and a cadaver donor transplant (RR, 4.76; P = 0.039). Multivariate analysis of time-dependent variables showed that delayed graft function recovery (RR, 2.20; P = 0.019) and the need to add steroid and/or azathioprine therapy (RR, 5.28; P = 0.000) were also correlated with a lower graft survival. Patients who added steroid therapy developed infections (P < 0.001), cataracts (P < 0.001), cardiovascular complications (P = 0.004), and arterial hypertension (P = 0.024) more frequently than patients remaining on CsA monotherapy. Patients administered CsA in a single daily dose received significantly less CsA over the years (P = 0.0042) than patients administered CsA in two divided doses. They also showed a trend toward greater creatinine clearance levels, although not statistically significant. In conclusion, this analysis showed that in patients assigned to CsA therapy alone, good long-term patient and graft survival probabilities can be obtained. In approximately one third of the patients, the use of steroids could be avoided for up to 11 years, and these patients had a better long-term outcome than those who required the addition of steroid therapy. Finally, in patients administered CsA in a single daily dose, the possibility of reducing CsA dosage probably led to better intrarenal hemodynamics with improving creatinine clearances.

Calcium ATPase in erythrocytes of spontaneously hypertensive rats of the milan strain

Calcium (Ca)-dependent ATPase activity was determined in erythrocyte membrane ghosts from normal and spontaneously hypertensive rats of the Milan strain in order to detect changes in enzyme activity which had previously been shown in the spontaneously hypertensive rat strain. Activity was similar in control and hypertensive rats in the absence of calmodulin. In contrast, activity in the presence of saturating amounts of calmodulin was significantly lower in the hypertensive rats. At the Vmax (free Ca2+ concentration 10 mumol/l) the decrease was about 30% (70.1 +/- 8.94 versus 49.1 +/- 4.75 nmol of ATP split/mg of ghost proteins per min; P less than 0.05). The affinity of the ATP-dependent Ca2+ pump for Ca2+ (Km about 1 mumol/l) was not altered in the hypertensive rats. It is possible that deficient Ca ATPase activity sustains an increase of intracellular free Ca in cells of hypertensive rats concomitant with the intracellular sodium (Na) decrease typical of this strain.

Effect of Cyclosporin A on Renal Cortical Resistances Measured by Color Doppler Flowmetry on Renal Grafts

Doppler spectra were recorded at different cyclosporin A (CSA) levels (trough and peak) in 30 stable renal-transplanted outpatients: 15 with unimpaired renal function (plasma creatinine < 150 mumol/l) and 15 with renal impairment (plasma creatinine 150-350 mumol/l). Pulsatility (PI) and resistive indexes (RI) have been measured in the renal artery at the hilum and in the renal cortex. RI and PI were markedly increased (p < 0.0001) in the cortex at peak time while in the renal artery no significant changes were observed. These variations were statistically related with CSA blood levels (PI = p < 0.02; r = 0.54, RI = p < 0.05; r = 0.45). These effects were also found in the presence of renal damage. CSA dose-dependently reduces cortical blood flow, causing a persistent arteriolar vasoconstriction and a reduction in diastolic flow. This effect can be measured in man in a noninvasive and repeatable way using color Doppler sonograms.

High Plasma Ionized Calcium with Normal PTH and Total Calcium Levels in Normal-Function Kidney Transplant Recipients

Hypercalcemia is a postrenal transplant complication. We found a high frequency of elevated plasma ionized calcium values (65.8%) in 41 normal-function renal graft recipients. In 8 patients increased free calcium was associated with high PTH levels, whereas in 19 PTH was not increased but free calcium was high. In the other 14 patients both free calcium and PTH were in the normal range. The mean transplant duration was different in the three groups: shorter in high PTH patients, longer in normal free calcium patients, intermediate in normal PTH and high free calcium patients. Our findings confirm that a condition of hyperparathyroidism persists in the first post-transplant period, and suggest that this complication evolves towards normalization of the blood chemistry values, passing through a condition of inappropriate PTH secretion with elevated plasma free calcium which in this period is the only marker of parathyroid hyperfunction.

Metabolic effects of a corticosteroid-free immunosuppressive regimen in recipients of pancreatic transplant

Background. A corticosteroid (CS)-free immunosuppressive regimen may be considered less diabetogenic than treatments including CSs principally after pancreas transplantation. Methods. To test whether a CS-free immunosuppressive treatment is metabolically superior to a regimen including CSs, we prospectively studied 19 CS-free simultaneous pancreas and kidney (SPK) transplant recipients (body mass index=22±1 kg/m2; cyclosporine dose=400±19 mg/kg/day; azathioprine dose=77±8 mg/day; basal plasma C-peptide=1.3±0.12 ng/mL) and 12 matched CS-treated SPK transplant recipients (prednisone dose=9±1 mg/day; basal C-peptide=2.2±0.2 ng/mL) by means of the 6,6-2H2-glucose infusion and the euglycemic insulin clamp (1 mU/kg/min, insulin infusion rate). In addition, six renal transplant recipients receiving a CS-free regimen were also studied as a control group. Results. In the postabsorptive state, CS-treated SPK transplant recipients demonstrated comparable plasma glucose levels but higher plasma insulin levels than CS-free SPK transplant recipients. Plasma triglyceride levels were significantly higher in CS-treated SPK patients than in CS-free SPK patients (1.16±0.16 mg/dL vs. 0.88±0.08; P <0.05). High-density lipoprotein and apoprotein A1 levels were similar in both groups. No difference was observed in pyruvate, lactate, &bgr;-OH-butyrate, and basal endogenous glucose production in all three groups of patients studied. During euglycemic hyperinsulinemia, the inhibition of endogenous glucose production and the stimulation of tissue glucose disposal were not statistically different among the three groups. Conclusions. SPK recipients receiving chronic low-dose CS maintenance therapy do not present a lower glucose disposal than CS-free recipients. Nonetheless, this is obtained at the expense of a higher endogenous insulin secretion, which can cause an alteration of the triglyceride profile.

The clinical status of cadaveric renal transplant patients treated for 10 year with cyclosporine therapy

In this paper we assessed the clinical status of 150 cadaveric renal transplant patients who received cyclosporine without interruption for 10 yr. The mean creatinine clearance was 59.2±15.71 at 1 yr and 55.6±24.91 mL/min at 10 yr (p=0.039). Patients were subdivided into four quartiles according to the mean creatinine clearance at 1 yr. The 14 patients with the lowest quartile showed a significant decrease of creatinine clearance from the 1st to 10th year (from 31.5±5.83 to 24.8±14.00 mL/min; p=0.038) while no difference between the mean creatinine clearance at 1 and at 10 yr was found in the other three quartiles. At 10 yr, 84.6% patients needed antihypertensive therapy, a rate similar to that seen at 1 yr (81.4%). The mean plasma cholesterol (253±57.8 mg/dL) and triglyceride (197±113.1 mg/dL) at 10 yr were similar to those found at 1 yr (243±48.2 and 201±143.0 mg/dL, respectively). Most patients have a high degree of rehabilitation 10 yr after uninterrupted cyclosporine therapy and all patients but 3 were able to work.

Fibrillary Glomerulonephritis in Castleman's Disease

Castlemans disease is an uncommon lymph node disorder which can be associated with renal disease. In this report we describe a patient with fever, weight loss, anorexia, increase in inflammatory proteins, anemia and nephrotic syndrome. Castlemans disease, plasma cell type, was diagnosed by histologic analysis after surgical excision of a pelvic lymph node. The disease was considered localized, since further investigations did not show any other pathologic mass. After resection of the pelvic lymphoid mass, clinical remission of systemic symptoms and laboratory abnormalities was observed, with the exception of the nephrotic syndrome. Renal biopsy was performed and showed a pattern compatible with fibrillary glomerulonephritis. Progressive decline in renal function was observed, despite immunosuppressive therapy.

The well-functioning renal graft evaluated by color Doppler flowmetry

The value of color Doppler ultrasound in the renal transplant follow-up has been evaluated. To do so we used a standardized protocol of analysis on a group of 86 outpatients with different transplant ages and a good and stable graft function defined as a plasma creatinine level < 105 microM/l. Renal volume increased after transplantation and averaged 198 +/- 54 cm3. The graft volume was positively related to the transplant age (p = 0.04). Mean renal blood flow/1.73 m2 body surface area was 301 +/- 98 ml/min, a value at the lower limit of normality. A statistical inverse relationship between renal blood flow and transplant age was found (p = 0.04). Renal vascular resistances increased along with the transplant age (p = 0.003). Renal function evaluated by creatinine plasma levels and creatinine clearance values did not show any statistical correlation with color Doppler findings in normal grafts. In conclusion, ultrasound measures allow us to obtain more sensitive information about the graft status and might be used for a better evaluation of the transplant follow-up.

Nonacidotic kidney proximal tubulopathy with absorptive hypercalciuria

We studied three patients with proximal tubulopathy characterized by defective reabsorption of phosphate, glucose, amino acids, urate, and low molecular weight proteins. This tubulopathy differs from Fanconi syndrome in that the patients had normal plasma bicarbonate and absorptive hypercalciuria associated with increased 1,25-dihydroxyvitamin D levels. The youngest patient was rachitic and may be classified with previously described patients, whereas the other two patients presented with nonrachitic osteopenic bone disease and their tubulopathy started during adult life. Kidney defects appeared sequentially in one of the nonrachitic patients. The two brothers of the youngest patient had similar kidney and bone disturbances. One of the other two patients had a brother with similar kidney reabsorption defects; an additional brother was probably affected and a sister presented with glycosuria, but no other reabsorption defects. The findings in these two families suggest a genetic transmission of proximal tubulopathy. The third case was sporadic. Renal histology of the three patients showed a great number of giant cells in the tubular lumen. We conclude that, at least in our adult patients, tubulopathy may represent a new entity among the proximal tubular dysfunction cases described to date. The features of this proximal defect suggest that it may be caused by a selective alteration of luminal cell membrane transport of phosphate, glucose, amino acids, urate, and proteins in the presence of a normal sodium gradient across the tubular cell membrane.