Conservative long-term treatment of chronic renal failure with keto acid and amino acid supplementation

In a group of 119 patients with advanced chronic renal failure (serum creatinine level 733 +/- 186 mumol/l) the effect of a low-protein diet supplemented with essential amino acids (EAA) or their keto analogues (KA) on uremic metabolism and rehabilitation status was investigated. The protein intake amounted to 0.4 g/kg B.W./day, the phosphorus intake 0.4-0.6 g/day and the energy supply 120-150 kJ/kg B. W./day. In 51 patients there was a substitution with EAA and in 68 patients with their KA. The mean duration of dietary treatment in this study was 19 months (6-64 months). During this time, the serum creatinine increased from 733 +/- 186 to 1,220 +/- 256 mumol/l, whereas the urea nitrogen values remained relatively constant at between 26 and 30 mmol/l. There were no signs of protein malnutrition (nitrogen balance, serum transferrin and serum protein were normal). The hemoglobin concentration remained at greater than 5 mmol/l with creatinine levels of 1,220 +/- 256 mumol/l. During the substitution with KA, there was a significantly greater decrease in serum phosphate (p less than 0.05) and parathyroid hormone (PTH) (p less than 0.01) as compared with the uremics given EAA. In addition, we found a significant increase in testosterone (p less than 0.01) in patients supplemented with KA. Despite advanced chronic renal failure there was a good degree of rehabilitation (full-time work: 21%; part-time work: 66.4%). It can be concluded that a low-protein diet supplemented with EAA or KA can improve the uremic metabolism, rehabilitation status and safely postpone the start of maintenance dialysis.

Influence of diet and underlying renal disease on the rate of progression of chronic renal failure

The data presented demonstrate that the underlying renal disease and the type of diet used are considerably influencing the rate of progression of chronic renal failure. In relative terms the course of the renal disease is mostly changed in patients suffering from glomerulonephritis, while in absolute terms patients suffering from polycystic kidney disease exhibit the slowest rate of progression. The comparison suggests that a low-protein diet purely based on vegetarian food might considerably slow down the overall rate of progression of chronic renal failure. This finding is supported by results obtained in animal experiments.

Effect of different levels of protein intake on renal deterioration and nutritional state in experimental renal disease

We examined the effects of various levels of dietary protein on the course of adriamycin-induced nephropathy in rats fed with high (30%), intermediately low (10%) or strictly low (5%) protein diets for 24 weeks. In the rats fed on the 30% protein diets, there were massive proteinuria, progressive increases in serum creatinine and focal glomerular sclerosis associated with severe tubulo-interstitial changes. With the 5% dietary protein, proteinuria was decreased, the levels of serum creatinine were preserved within normal ranges and renal histological changes diminished. Weight loss and hypoproteinaemia were more marked. With intermediate protein restriction (10% protein), renal function and plasma protein were preserved but body weight did not increase normally. Aggregated human immunoglobulin G, which had been intravenously injected at weeks 12 and 24, accumulated in the glomeruli more densely in rats fed on the 30% protein diet than in those fed on the 10% or 5% protein diets. We tentatively conclude that functional and histological deterioration of focal glomerular sclerosis can be prevented by appropriate restriction of dietary protein; however, severe protein restriction does aggravate nutritional states.

Selective effect of low protein diets in chronic renal diseases

It has recently been established that the rate of progression of chronic renal failure in man can be slowed by restricting dietary protein. Consequently, the short term and long term effects of a low protein diet on the course of different chronic nephropathies were studied in an attempt to delineate the factors that determine the response to such a diet. When a low protein diet was given for six months renal function improved significantly in nine patients with chronic tubulointerstitial nephritis (p less than 0.025); the diet had a marginally beneficial effect in 12 patients with chronic glomerulonephritis (p less than 0.05) and no effect in nine with hypertensive nephrosclerosis. The heterogeneous functional response in the patients with chronic glomerulonephritis correlated closely with the effect of the diet on these patients' proteinuria (r = 0.76, p less than 0.01). In a short term study (four weeks) of 12 patients with chronic renal failure changes in renal plasma flow were proportional to dietary protein intake. Renal vascular resistance fell during a high protein diet and increased when dietary protein was restricted. The changes in renal plasma flow during the low protein diet correlated well with the patients' long term functional response to the diet (r = 0.76, p less than 0.01). It is concluded that the response to a low protein diet in chronic renal failure is determined, firstly, by the nature of the underlying nephropathy, with maximal benefit being observed in non-glomerular disorders; secondly, by the effect of the diet on the proteinuria in chronic glomerulonephritis; and, thirdly, by the haemodynamic response to the diet, with patients with a reactive renal vascular bed improving with a low protein diet.

Amelioration of experimental glomerulonephritis by dietary protein restriction

We have examined the effects of various levels of dietary protein intake on the course of nephrotoxic serum nephritis in the rat by feeding low (4.6% casein), standard (23% casein), and high (57.5% casein) protein diets which were identical in calorie, mineral, and electrolyte content. Nephritic rats on a high protein diet manifested heavy proteinuria, hypoalbuminemia, hypercholesterolemia, azotemia, and elevated serum creatinine levels. In those subjected to dietary protein restriction, proteinuria remitted and azotemia did not develop. While mesangial widening, interstitial abnormalities, and segmental proliferation and sclerosis of glomeruli occurred regularly in nephritic rats fed high protein diets, histologic abnormalities were virtually absent in those on low protein intake. Animals on a standard protein intake manifested histologic and clinical features intermediate in severity. We conclude that the renal functional and histologic consequences of nephrotoxic serum nephritis can be averted by dietary protein restriction.

[Lipid metabolism and free-radical oxidation in children with glomerulonephitis incorporating plant fats into their diet]

A study was made of the effect of vegetable fats on lipid metabolism and free radical oxidation, phospholipase activity and antioxidant content in 43 children suffering from chronic glomerulonephritis. After intake of a vegetative fat in a dose of 2 g/kg bw for 7 days the sick children demonstrated a significant rise in the level of total lipids in red cells and in their excretion with urine. This was in a good agreement with an increase in phospholipase activity in blood and diminution of lipid peroxides in red cell membranes. The reaction of antioxidant enzymes metabolizing hydrogen peroxide was different. Catalase activity in urine was elevated, whereas urine peroxidase activity was decreased. All these changes gave rise to a decrease in the pool of peroxide radicals which correlated with the time course of hydroperoxides. The biochemical data indicate that lipids contained by vegetative fats may be regarded as treatment-and-dietetic factor in multiple modality therapy of children with renal diseases.

Progression rate of residual renal function in conservative treatment and early dialysis

A retrospective comparative study was carried out in patients with chronic renal failure on conservative treatment (26 cases) and early dialysis (23 cases). The two groups were well matched for age, sex, etiology of renal disease and residual Ccr. In contrast with other papers, patients on dialysis showed a gentler deterioration rate of residual renal function than those on conventional low protein diet regimen. Between the two groups statistically significant differences concerned the control of blood pressure, serum phosphate and uric acid.

Dietary enrichment with the polyunsaturated fatty acid eicosapentaenoic acid prevents proteinuria and prolongs survival in NZB x NZW F1 mice

Prostaglandins and related compounds are active mediators of inflammation, but data concerning their role in the pathogenesis of the glomerulonephritis of New Zealand Black x New Zealand White (NZB x NZW) F1 mice are conflicting. Dietary eicosapentaenoic acid (EPA, C20:5), a fatty acid analogue of arachidonic acid (C20:4), has been shown to impair platelet aggregation in humans, apparently through inhibition of the synthesis of prostaglandins and thromboxanes from arachidonic acid. We report here the effects of a diet high in EPA on the development of renal disease and survival in female NZB x NZW F1 mice. Animals from 4--5 wk of age were fed diets containing 25% lipid, supplied either as beef tallow or menhaden oil, with fatty acid analysis of less than 0.05 and 14.4% EPA, respectively. In the first experiment, by 13.5 mo of age, mice on the beef tallow diet had all (9/9) developed proteinuria and the majority (6/9) had died, with renal histologic examination revealing severe glomerulonephritis. In contrast, none of 10 menhaden oil-fed animals had developed proteinuria, and all were alive at this time (P less than 0.005 for both proteinuria and survival). In a second experiment using 50 mice in each dietary group, 56% of the beef tallow group vs. none of the menhaden oil group had developed proteinuria at 9 mo of age (P less than 0.005). Native DNA binding at 6 mo of age was 23.9 +/- 14.7 vs. 10.1 +/- 9.7% in the beef and menhaden oil groups, respectively (P less than 0.01). Weights were similar in all groups, and there was no evidence of essential fatty acid deficiency in any group. These results demonstrate that a diet high in EPA protects NZB x NZW F1 mice from the development of glomerulonephritis.

Modulated nitrogen intake for patients on low-protein diets

In order to overcome malnutrition and poor palatability associated with long lasting low-protein intakes, a diet was devised based on modulated nitrogen intake and energy supply of at least 155 KJ/kg a day. Each patient underwent three different regimens (A, B, C) of protein intake. In period A, the protein intake was 0.33 g/kg a day. In period B, the patients were given 0.33 g/kg a day during day 1, 2, 3, 5, 6 and 1.00 g/kg a day during day 4 and day 7 of the week. In period C the daily protein intake was the mean of the weekly value from day 1 to 7 of period B. Data obtained show that in period A the urea appearance rate was equal to that in period B and lower than that in period C.

Preservation of renal function in experimental glomerulonephritis

To evaluate the protective effect of dietary phosphorus restriction in an immunologic model of experimental renal disease, we randomized 24 Sprague-Dawley rats with established nephrotoxic serum nephritis into two groups. Group A animals (N = 13) were fed a diet with a normal phosphorus content (0.5% phosphorus), and group B animals (N = 11) received an identical diet low in phosphorus (0.04% phosphorus). Over the ensuing 133 days, group A rats developed progressive renal failure and had a mean serum creatinine concentration of 3.0 +/- 0.5 mg/dl at the time of death or completion of the study. In contrast, group B animals maintained near normal renal function and had a final mean serum creatinine concentration of 0.93 + 0.2 mg/dl (P < 0.001). Survival was markedly improved in group B animals (P < 0.001). Histologic damage was diminished greatly in group B animals by both light and electron microscopy; immunofluorescence was positive in all animals. Group A animals had increased kidney calcium concentration (30 +/- 6 mmoles/kg) when compared to group B animals (18 +/- 1 mmoles/kg) and animals with normal kidneys (13 +/- 1 nmoles/kg, P< 0.001). Conclusion. Dietary restriction of phosphorus retards functional deterioration and reduces histologic damage in experimental immunologic renal disease. The mechanism for this protective effect has not been elucidated.

[Changes in lipid metabolic indices in children with chronic kidney diseases under the influence of diet therapy]

Variations in lipid metabolism were studied in 20 children with chronic glomerulonephritis (CGN) associated with the nephrotic syndrome and 14 children with chronic renal insufficiency given protein deficient therapeutic diets. Suggestive abnormalities of lipid metabolism involved hyperlipidemia, hypercholesterinemia and hypertriglyceridemia (more sharply pronounced in patients with CGN associated with the nephrotic syndrome) as well as hyperlipoproteidemia, chiefly of types IY and IIB. Disproportions in lipoproteid spectra of the plasma towards increase in atherogenous beta- and pre-beta-lipoproteids are characteristic for patients of both groups but sharply pronounced in CRI. These patients also show a reduced metabolization efficacy coefficient (MEC) of essential fatty acids of food to the lipid structures of erythrocyte membranes. As a results of the treatment the lipid metabolism returned to normal in most patients with CGN and in part of the patients with CRI. In order to raise the efficacy of therapeutic diets during normalization of lipid metabolism in CRI it is recommended that the fat and carbohydrate components of the diet may be changed qualitatively with due regard for the types of hyperlipoproteidemia.