Short-term effects of soy protein diet in patients with proteinuric glomerulopathies / Efeitos a curto prazo da dieta com proteína da soja em pacientes com glomerulopatias proteinúricas

INTRODUCTION: It has been suggested that soy protein can slow renal disease progression by decreasing plasma cholesterol and proteinuria in patients with nephropathies. This study was designed to evaluate the effect of soy protein on proteinuria and dyslipidemia, in patients with proteinuric glomerulopathies. PATIENTS AND METHODS: Patients were divided into three groups: Control Group (n = 9) received diet with 0.8 g/kg/day of animal protein; Study Group 1 (n = 9), 0.8 g/kg/day of soy protein; and Group 2 (n = 9), 0.8 g/kg/day of soy protein plus fibers. The study period corresponded to eight weeks. During the baseline period and by the end of the study, patients were submitted to laboratorial and anthropometric evaluation. RESULTS: There was no statistically significant difference between baseline and post-diet periods among the three groups in anthropometric parameters or body composition, neither in proteinuria levels (Control: 0.7 ± 0.6 versus 0.8 ± 0.6; Group 1: 2.0 ± 1.7 versus 1.9 ± 1.8; Group 2: 2.0 ± 1.4 versus 2.1 ± 2.0). However, a slight decrease in triglycerides (244.8 ± 275.9 versus 200.5 ± 34.0), total (234.0 ± 59.4 versus 181.2 ± 110.3) and LDL (136.0 ± 59.1 versus 104.1 ± 39.4) cholesterol in Group 1 was observed, although not significant. CONCLUSION: We have not observed beneficial effects when using soy protein instead of animal protein with the aim of attenuating proteinuria and hyperlipidemia, but we have shown that soy protein has not caused deleterious changes in body composition, ensuring an adequate nutritional state.

INTRODUÇÃO: Há indícios de que a proteína da soja poderia contribuir para reduzir a velocidade de progressão da doença renal, diminuindo colesterol sérico e proteinúria em pacientes com nefropatias. Este estudo foi desenvolvido para avaliar o efeito da die>ta com proteína da soja sobre proteinúria e dislipidemia, em pacientes com glomerulopatias proteinúricas. PACIENTES E MÉTODOS: Os pacientes foram divididos em três grupos: o Grupo Controle (n = 9) recebeu dieta com 0,8 g/kg/dia de proteína animal; o Grupo de Estudo 1 (n = 9) recebeu dieta com 0,8 g/kg/dia de proteína da soja e o Grupo 2 (n = 9), dieta com 0,8 g/kg/dia de proteína da soja mais fibras. O período de estudo foi de oito semanas. Durante o período basal e no final do estudo, os pacientes foram submetidos à avaliação laboratorial e antropométrica. RESULTADOS: Não foram observadas diferenças estatisticamente significantes entre os períodos pré e pós-intervenção em nenhum dos grupos estudados, nos parâmetros antropométricos ou na composição corporal entre os três grupos, nem nos níveis de proteinúria (Controle: 0.7 ± 0.6 versus 0.8 ± 0.6; Grupo 1: 2.0 ± 1.7 versus 1.9 ± 1.8; Grupo 2: 2.0 ± 1.4 versus 2.1 ± 2.0). No entanto, observou-se discreta diminuição nos níveis triglicérides (244.8+-275.9 versus 200.5+-34.0), colesterol total (234.0+-59.4 versus 181.2+-110.3) e LDL (136.0+-59.1 versus 104.1+-39.4) no Grupo 1, embora sem atingir significância estatística. CONCLUSÃO: Não foram detectados efeitos benéficos com a substituição da proteína animal pela proteína da soja em relação aos objetivos de reduzir proteinúria e hiperlipidemia; porém, constatou-se que a dieta de proteína da soja não causou alterações deletérias na composição corporal, mantendo um estado nutricional adequado.

Amelioration of systemic lupus erythematosus by Withangulatin A in MRL/lpr mice.

We have previously reported the anti-inflammatory potential and the possible underlying mechanisms of Withangulatin A (WA), which is an active component isolated from Physalis angulata L. Here, we demonstrated that WA might improve the life quality, as well as reduced the accumulation of proteinuria symptoms and levels of anti-double-stranded DNA antibodies in MRL/lpr mice. Moreover, WA could improve renal histopathologic characteristics of MRL/lpr mice. Intriguingly, expression of B cell-activating factor (BAFF), BAFF-R and related gene in the spleen were significantly reduced in 10 mg/kg WA-treated mice compared with that in 5 mg/kg WA-treated mice and untreated mice. These findings indicate that WA might have a pleiotropic therapeutic effect through their immunosuppression via inhibiting BAFF signaling, which suggest a potential application of this active constituent in the treatment of SLE.

Treatment of proteinuric patients with a vegetarian soy diet and fish oil.

Our aim was to determine whether a longer period of treatment with a vegetarian soy diet with addition of fish oil supplements would accentuate the beneficial effects on hyperlipidemia and proteinuria of nephrotic patients we found in a previous study. After an 8-week baseline period on free diet, patients were randomly allocated either on soy diet alone (SD) or to SD plus 5 g/day of fish oil (SD + FO) orally for two months. Then they crossed over to the other treatment for two additional months. They finally resumed eating the free diet for 3 months. We selected 20 outpatients with chronic glomerulonephritis, proteinuria in the nephrotic range, fasting serum cholesterol > 250 mg/dl, mean serum creatinine concentrations 1.75 +/- 0.23 mg/dl. Serum lipid profile, urinary protein loss and nutritional parameters were monitored. With the soy diet, we obtained a significant decrease both of hyperlipidemia and of proteinuria. The effect of the soy diet on proteinuria increased over the 4 months. The addition of a moderate amount (5 g/day) of fish oil in a randomized cross-over design had no further beneficial effect. Stability of serum albumin, transferrin and the body mass index documented good nutritional status. In conclusion, the dietary manipulation with our vegetarian soy diet confirmed the beneficial effects on hyperlipidemia and proteinuria of nephrotic patients. Such effects persisted and even ameliorated after 4 months of diet. The addition of moderate oral supplements of fish oil did not potentiate the beneficial effect.

Fish oil has protective and therapeutic effects on proteinuria in passive Heymann nephritis.

Passive Heymann nephritis (PHN) is a rat model of membranous nephropathy induced by injecting anti-Fx1A. The onset of proteinuria in PHN is caused by complement-mediated injury to glomerular epithelial cells (GEC) accompanied by enhanced glomerular eicosanoid production. In addition, sublethal injury by complement of rat GECs in culture leads to phospholipase activation, phospholipid hydrolysis and release of arachidonic acid and dienoic prostanoids. Based on these findings, we undertook to determine if substituting arachidonic acid (omega-6) in GEC membrane phospholipids with omega-3 fatty acids derived from fish oil would alter the development and course of proteinuria in PHN. We found that rats fed a diet containing 10% fish oil for four weeks prior to antibody injection developed 50 to 60% less proteinuria between two and six weeks after anti-Fx1A than rats fed an equivalent diet containing 10% safflower oil, and had substantial enrichment of glomerular phospholipids with omega-3 fatty acids and displacement of arachidonic acid. This outcome was associated with a 50% reduction in release of glomerular thromboxane B2 (stable metabolite of thromboxane A2) in the fish oil group. More importantly, when PHN rats with well established proteinuria while on regular chow were randomized to three dietary groups, those fed fish oil had a 25 to 50% decline in proteinuria as compared to those fed lard or safflower oil. This difference was evident within two weeks of randomization and persisted until the end of the study after eight weeks. In neither study could the differences in urine protein excretion be accounted for by protein or calorie deprivation, or by differences in blood pressure, renal function, immune response to sheep IgG, or glomerular deposition of IgG or complement. Thus, our results indicate that dietary fish oil has protective and therapeutic effects with regard to proteinuria in PHN. These benefits may relate to alterations in membrane phospholipid composition in favor of omega-3 fatty acids and release of less reactive trienoic eicosanoids.

Preservation of peripheral nerve function in severe uremia during treatment with low protein high calorie diet and surplus of essential amino acids.

Twelve patients with severe chronic renal failure (serum creatinine 7.0-27 mg %), and marked uremic symptoms on a 40 g protein diet, were treated with a caloric-rich diet containing 16-20 g protein, supplemented with the 8 essential amino acids (1.1-2.2 g N) and histidine (0.23-0.45 g N)in the form of tablets for periods between 3 and 34 months. During the treatment the serum urea-N fell, and the uremic symptoms subsided or diminished without the patient exhibiting signs of malnutrition. The nerve function was followed with quantitative and semiquantitative neurological tests (among others, determination of vibratory perception thresholds and nerve conduction times). Initially all patients but 2 had signs of neuropathy as measured by these methods. During the course of treatment no deterioration of peripheral nerve function was recorded in any of the patients, several of whom had had serum creatinine conceptrations above 15 mg % for long periods. We conclude that conservative treatment with N-poor diet in far advanced chronic renal failure may prevent the further development of peripheral neuropathy provided that adequatecaloried and essential amino acids (2-3 times the minimal requirements) are supplied. The results suggest that, in addition to uremic toxines, malnutrition is a factor of importance for the developments of of uremic neuropathy.