Sergio Giovannetti

Effects on Renal Function of a Low-Nitrogen Diet Supplemented with Essential Amino Acids and Ketoanalogues and of Hemodialysis and Free Protein Supply in Patients with Chronic Renal Failure

Creatinine clearance has been repeatedly measured in three groups of chronic uremics. In the first control group (31 cases), following a conventional low-protein diet, creatinine clearance declined linearly with time. In the second group (12 cases), following very low nitrogen diet supplemented with essential amino acids and ketoanalogues, creatinine clearance remained practically constant with only one exception in which it continued to decline. In the third group of uremics (13 cases) on repeated dialysis therapy, the deterioration of creatinine clearance was markedly accelerated. The possible explanations and the practical implications of these findings are discussed.

A Low-Nitrogen Low-Phosphorus Vegan Diet for Patients with Chronic Renal Failure

The nutritional treatment of chronic renal failure with a low-protein low-phosphorus diet (conventional low-protein diet, CLPD) is effective in reducing uremic intoxication, slowing the progression of renal failure and preventing secondary hyperparathyroidism. Unfortunately, in some patients, the poor palatability and the high cost of the protein-free substitutes, together with difficulties in following the diet away from home, can make good compliance difficult, possibly causing low energy intake and malnutrition. Here the results are reported of an attempt we made to overcome these drawbacks, using a diet supplying only natural foods of plant origin in definite proportions to give an essential amino acid supply satisfying the recommended dietary allowance. This is possible thanks to an appropriate cereal-legume mixture, supplying proteins complementary for essential amino acids. Additional positive features of this special vegan diet (SVD) are the high ratio of unsaturated to saturated fatty acids, the absence of cholesterol, and the lower net acid production in comparison with a mixed diet. This study indicates that the results obtained with the SVD are similar to those obtained with the CLPD. Therefore the SVD can be a substitute for the CLPD in the management of patients with mild chronic renal failure. The SVD is the diet of choice when products made of starch are not available or poorly tolerated.

Comprehensive Study of Haemostasis in Nephrotic Syndrome

A comprehensive study of haemostasis has been performed in a homogeneous group of 20 patients with nephrotic syndrome without renal failure. We have found unchanged number of platelets and a significant increase of platelet adhesiveness and aggregation; increased levels of activity and related antigen of fibrinogen, of factor VIII, of activity of factors II, VII and X and of antigens of factors XIII. Antithrombin III was unchanged in plasma and was detected in the urine. Euglobulin lysis times were decreased, and levels of plasminogen and its activators were increased after a venous occlusion test. At the same time urokinase inhibitors and antiplasmins were increased not only after, but also before a venous occlusion test. Fibrinogen degradation products have been found in the urine of all our patients but not in their sera.

In Defense of Creatinine Clearance

The ratios creatinine clearance (Crcl)/inulin clearance (INcl) obtained in 523 measurements and reported in 14 papers have been analyzed and the values of CRcl corresponding to those of INcl have been evaluated. The day-to-day coefficient of variation of CRcl has also been measured in 123 persons, including patients with stable chronic renal failure and patients with normal renal function. The data obtained indicate that CRcl is not less sensitive than INcl, and that its changes are not blunted, if compared with similar changes of INcl. The day-to-day coefficient of variation has been found not to be greater than that of INcl. In conclusion, CRcl is not a misleading method to obtain approximate information on renal function, if it is correctly executed and interpreted.

Reversal of Hyperparathyroidism in Severe Uremics Following Very Low-Protein and Low-Phosphorus Diet

Serum iPTH levels decreased markedly in 16 severe chronic uremic patients who changed from a standard low-protein diet to a very low-nitrogen and very low-phosphorus diet supplemented with essential a

A Special, Supplemented ‘Vegan’ Diet for Nephrotic Patients

High dietary protein intake, in the past recommended for nephrotic syndrome, does not improve hypoproteinemia and may accelerate progressive renal damage. In contrast, low-protein diets reduce proteinuria and preserve renal function in experimental renal models of nephrotic syndrome. In this study, 20 steroid-resistant, nephrotic patients were treated with a pure vegetarian, low-protein diet, supplemented with essential amino acids and ketoanalogues (supplemented vegan diet, SVD) for 4.6 +/- 3.1 months. Before the study, these patients followed an unrestricted protein, low-sodium diet (LSD). Proteinuria, daily urea nitrogen excretion and creatinine clearance decreased significantly on SVD. A similar lowering effect of SVD was observed on serum total cholesterol. Seven of the 20 patients changed from LSD to SVD and vice-versa on 3 occasions, and in all cases, we found an increase of proteinuria during the LSD period. Serum albumin, HDL cholesterol, triglycerides and anthropometric measurements did not change on SVD. Our data suggest that SVD exerts a favorable effect on proteinuria and hypercholesterolemia in nephrotic patients, without inducing clinical or laboratory signs of malnutrition.

Secondary Hyperparathyroidism in Severe Chronic Renal Failure Is Corrected by Very-Low Dietary Phosphate Intake and Calcium Carbonate Supplementation

The main purpose of our study was to verify the effect of a very-low-protein, low-phosphorus diet, supplemented with essential amino acids and keto analogues and with calcium carbonate, on circulating levels of intact parathyroid hormone (i-PTH) in severe chronic renal failure patients with secondary hyperparathyroidism, not treated with any vitamin D preparation. To this aim, we shifted 21 chronic uremics (12 males, 9 females; age 56 ± 13 years) with serum creatinine >6.5 mg/dl and i-PTH >150 pg/ml, from a standard low-protein diet (0.6 g/kg/day approximately) to a very-low-protein (0.3 g/kg/day), very-low-phosphorus (5 mg/kg/day) diet supplemented with a mixture of essential amino acids and calcium keto analogues (Ketodiet), calcium carbonate (2–4 g/day), iron, and vitamin B12 preparations. The energy supply of both diets was 30–35 kcal/kg/day. Exclusion criteria were a poor compliance with dietary or supplement prescriptions or signs of autonomic hyperparathyroidism. After 4 ± 2 months of Ketodiet, the i-PTH serum levels decreased by 49% as a mean (from 441 ± 233 to 225 ± 161 pg/ml, p < 0.001); serum phosphorus and alkaline phosphatase decreased, whereas serum calcium increased. The great reduction of serum and urinary urea demonstrated a good compliance with Ketodiet, and no sign of protein malnutrition was observed. These findings confirm that even in severe chronic uremic patients dietary phosphorus restriction and calcium carbonate supplementation lower i-PTH serum levels. This is one of the goals of the dietary treatment that can be safely achieved, provided good compliance both with the dietary prescriptions and with adequate energy and supplement intakes.

Free-hand ultrasound-guided renal biopsy: report of 650 consecutive cases.

In the past 4 years we have carried out 650 percutaneous renal biopsies (PRB), 54 on transplanted and 596 on native kidneys. PRB was performed with a 14-gauge one-piece disposable needle that was introduced free-handedly into the lumbar wall without any form of fixed guidance or support. Ultrasound was used to locate the kidney pole and to follow the progression of the needle tip in the renal parenchyma. The time needed for the whole procedure was about 5 min. The tissue specimen was adequate for histological evaluation in 98.8% of the cases. The prevalence of post-biopsy complications (haematuria, pain, anaemia) was 2.5%. Haematuria was not a common complication (1.6%) in our series, whereas clinically silent perirenal haematoma was common. Mild perirenal bleeding (volume < 5 ml) was found in 40 of a series of 150 patients (26.6%) who underwent ultrasound scan 24 h after the PRB. Haematoma exceeding 100 ml was revealed with US in only 0.6% of the patients. We conclude that free-hand ultrasound-guided PRB makes this technique easier, highly successful, time-saving and almost free of severe side effects.

Oral Activated Charcoal in Patients with Uremic Pruritus

Twenty-three chronic uremic patients on maintenance hemodialysis and suffering from severe pruritus were treated with activated powdered charcoal (6 g daily p.o.). In 10 patients pruritus disappeared completely, and in 10 other patients a partial effect was observed. The favorable results persisted for several weeks after discontinuation of the treatment. Only 3 cases were totally unresponsive. No relevant undesirable side effects were observed with the exception of 1 case who showed treatment intolerance. It is concluded that activated charcoal per os is a safe, effective, and low-cost therapy for patients with uremic pruritus, but its mechanism of action is unknown.

Comprehensive study of haemostasis in chronic uraemia.

A comprehensive study of haemostasis has been performed in a homogeneous group of 25 adult patients with conservatively treated chronic uraemia. We have found prolonged bleeding time, impaired platelet adhesiveness and aggregation, and decreased platelet factor 3 activity, increased values of fibrinogen, of factor VIII activity and related antigen, and of combined levels of factors II, VII and X. Non-significantly abnormal concentrations of factor XIII and of plasminogen and significantly lower values of plasminogen activators and higher values of urokinase inhibitors and anti-plasmin have also been found. Fibrinogen degradation products were detected in the urine of some patients.