Effects of Cranberry Extract (Vaccinium macrocarpon) Supplementation on Lipid Peroxidation and Inflammation in Patients with Chronic Kidney Disease (Stages 3-4): A Randomized Controlled Trial

Background

Growing evidence suggests that bioactive compounds in berry fruits may mitigate inflammation in patients with chronic kidney disease (CKD).

Objectives

To evaluate cranberry (Vaccinium macrocarpon) supplementation effects on modulation of transcription factors involved in inflammation and oxidative stress in nondialysis (stages 3 and 4) patients with CKD. Design/Participants. A randomized, double-blind, placebo-controlled study was performed with 30 patients to receive capsules containing cranberry extract (1000 mg/day) or placebo (1000 mg/day of corn starch) for two months. Measurements. The mRNA expression of nuclear factor-erythroid 2-related factor-2 (Nrf2) and nuclear factor-kB (NF-kB) was evaluated in peripheral blood mononuclear cells (PBMCs) by quantitative real-time polymerase chain reaction. Thiobarbituric acid reactive substances (TBARS) were measured in the plasma to assess oxidative stress. Interleukin-6 (IL-6) plasma levels were assessed by enzyme-linked immunosorbent assay and C-reactive protein (CRP) by immunoturbidimetric method.

Results

Twenty-five patients completed the study: 12 in the cranberry group (56.7 ± 7.5 years and body mass index (BMI) of 29.6 ± 5.5 kg/m2) and 13 in the placebo group (58.8 ± 5.1 years and BMI 29.8 ± 5.4 kg/m2). There were no differences in NF-kB or Nrf2 mRNA expressions (p = 0.99 and p = 0.89) or TBARS, CRP, and IL-6 plasma levels after cranberry supplementation.

Conclusions

The cranberry extract administration (1000 mg/day) did not affect Nrf2 and NF-kB mRNA expression, oxidative stress, or inflammatory markers levels in nondialysis CKD patients. This trial is registered with NCT04377919.

Albumin-to-protein ratio in spot urine samples for analysis of proteinuria selectivity in chronic kidney disease

INTRODUCTION

The albumin-to-creatinine ratio and total protein-to-creatinine ratio in spot urine samples have already been validated as surrogates for 24-hour albuminuria and proteinuria measurements. Thus, we hypothesized that the type of proteinuria, detected by the electrophoretic pattern of 24-hour urine, could be predicted by the simple proportion of albumin in the total urine protein content, using the albumin-to-protein ratio (APR). Our study sought to validate the use of APR as a cheaper substitute for urinary protein electrophoresis (UPE).

METHODS

Using different mathematical models, we compared, the albumin fraction in 24-hour urine samples by electrophoresis and the APR ratio in spot samples from 42 outpatients with chronic kidney disease (CKD).

RESULTS

A strong log-order correlation r = 0.84 (0.75-0.92; 95% CI, p = 0.001) was observed between APR and the albumin fraction in the UPE.

CONCLUSION

The APR can substitute electrophoresis in CKD outpatients.

Razão albumina/proteína em amostras isoladas de urina para análise da seletividade de proteinúria na doença renal crônica

Resumo Introdução: A utilização da razão albumina/creatinina e da razão proteína total/creatinina em amostras isoladas de urina já foram validadas como substitutos para a albuminúria e proteinúria em 24 horas. Assim, nossa hipótese é que o tipo de proteinúria, dado pelo padrão eletroforético da urina de 24 horas, poderia ser previsto pela simples proporção de albumina no conteúdo total de proteínas na urina, utilizando a razão albumina/proteína (RAP). O presente estudo procurou validar o uso da RAP como um substituto mais prático e de menor custo da eletroforese de proteínas urinárias (EPU). Métodos: Foram utilizados diferentes modelos matemáticos a fim de comparar a fração de albumina pela eletroforese em amostras de urina de 24 horas e a RAP em amostras isoladas em 42 pacientes ambulatoriais com doença renal crônica. Resultados: Foi observada uma forte correlação logarítmica r = 0,84 (0,75–0,92; 95% CI, p = 0,001) entre a RAP e a fração de albumina pela EPU. Conclusão: A RAP pode substituir a eletroforese urinária em pacientes renais crônicos ambulatoriais.

Cranberries – potential benefits in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) present many complications that potentially could be linked to increased cardiovascular mortality such as inflammation, oxidative stress, cellular senescence and gut dysbiosis.

Impact of gender in early structural changes of contrast induced nephropathy in rats

INTRODUCTION

Contrast-induced nephropathy (CIN) is a major iatrogenic cause of acute kidney injury. Experimental studies have shown that intravascular injection causes intense vacuolization of the contrast agent in the proximal renal tubules cells, preceding the increase in serum creatinine, and that the female may be at a higher risk for CIN.

OBJECTIVE

To study the early kidney histomorphometric changes in contrast-induced nephropathy according to the gender.

METHODS

Twenty previously uninephrectomized Wistar rats were divided into 4 groups (n = 5): control males; control females; contrast exposed males; and contrast exposed females. The animals were sacrificed immediately after contrast administration and kidney tissue samples were collected for histomorphometric analysis. The research project was approved by the Research Ethics Committee of the School of Medicine of Universidade Federal Fluminense.

RESULTS

There was a more intense presence of microvacuoles in proximal tubules in the rats exposed to contrast than in the control groups. Such proximal tubular vacuolation was more intensive in the female rats (p = 0.001).

CONCLUSION

Proximal tubular vacuolation is a very early change in CIN and is more intensive in female than in male rats.

Urinary tract infection and indwelling urinary catheters: prospective study in gynecological surgery with antibiotic prophylaxis

CONTEXT AND OBJECTIVES

Urinary tract infections are the most common cause of hospital-acquired infections, and the use of indwelling urinary catheters is a predisposing factor for their development. The aims of this study were to estimate the frequency of pre and postoperative bacteriuria, identify the microorganisms involved, count the colony-forming units, determine the antibiotic sensitivity profile and compare the results from pre and postoperative urinalyses among women undergoing gynecological surgery with implantation of a urinary catheter.

DESIGN AND SETTING

Non-controlled prospective observational single-cohort epidemiological study carried out at a university hospital.

METHODS

Urine samples were collected before and 24 hours after catheterization for urinalysis, culturing and antibiotic sensitivity testing. Pre and postoperative urinalyses were compared using Wilcoxon and McNemar non-parametric tests.

RESULTS

Fifty-one women participated in the study. Escherichia coligrew in six preoperative samples (11.8%) and Klebsiella pneumoniae in one (1.9%), but bacterial growth did not occur in any postoperative sample. Urinalysis showed lower number of pus cells in the postoperative urine samples (P < 0.05). There were no differences in red blood cell counts or in the nitrite and leukocyte esterase tests, between the samples.

CONCLUSION

Bacteriuria was found in 13.7% of the preoperative samples. Gram-negative bacteria sensitive to most antibiotics were identified. In the postoperative samples, no bacterial growth was observed. Urinalysis only showed significant reduction of leukocyturia in the postoperative period.

Is there association between uric acid and inflammation in hemodialysis patients?

BACKGROUND

Elevated serum uric acid has been associated with a variety of cardiovascular disease and with inflammation, but these have been little explored in chronic kidney disease (CKD). Elevated uric acid levels are common in CKD patients and could be involved in inflammatory milieu; our aim was to analyze the association between uric acid and inflammatory markers in hemodialysis (HD) patients.

DESIGN

This was a cross-sectional study.

SETTING

This study was conducted from private clinic, Rio de Janeiro, Brazil.

PATIENTS

This study included 50 HD patients and 21 healthy subjects.

METHODS AND PROCEDURES

This study included 50 HD patients [62% men, 54.3 ± 12.6 years, 57.5 ± 50.1 months on dialysis, and body mass index (BMI), 24.4 ± 4.1 kg/m2] and 21 healthy individuals (45% men, 50.7 ± 15.7 years and BMI, 25.5 ± 4 kg/m2). Uric acid was measured using uricase-PAP method; inflammatory [tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP)] and atherosclerosis markers [intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1)] were measured by a multiplexed assay.

RESULTS

PATIENTS presented high levels of TNF-α, IL-6, CRP, VCAM-1, ICAM-1 (5.5 ± 2.1 pg/mL, 4.1 ± 1.6 pg/mL, 0.32 ± 0.30 mg/mL, 48.5 ± 8.5 ng/mL, 20.5 ± 15.9 ng/mL, respectively), compared with healthy individuals (2.4 ± 1.1 pg/mL, 2.7 ± 0.4 pg/mL, 0.11 ± 0.12 mg/mL, 23.8 ± 5.5 ng/mL, 7.2 ± 1.2 ng/mL, respectively) ( p < 0.04). Uric acid levels were also higher in HD patients (5.4 ± 1.3 mg/dL) than in healthy individuals (3.9 ± 0.9 mg/dL) ( p < 0.02). There was a positive correlation between uric acid and inflammatory markers, IL-6 (r = 0.30, p = 0.01), CRP (r = 0.37, p = 0.003), TNF-α (r = 0.40, p = 0.001), ICAM-1 (r = 0.53, p = 0.0001), and VCAM-1 (r = 0.45, p = 0.0001).

CONCLUSION

These original data suggest that uric acid may have a role in inflammation and atherosclerosis in HD patients. However, further prospective studies involving intervention trials should be conducted in order to search for actual causality relationship between these markers.

Effect of sex hormones on gentamicin-induced nephrotoxicity in rats

1. There is clinical and experimental evidence that females are more susceptible to gentamicin-induced nephrotoxicity. To assess the role of sex as a risk factor in aminoglycoside-related acute renal failure 16 groups of five 120 +/- 15-day old (young adult) Wistar rats of both sexes, castrated and non-castrated, were treated with gentamicin. These rats were medicated with 40 mg kg-1 24 h-1 gentamicin alone for 10 days. Some animals received gentamicin after 5 days of treatment with depot testosterone or estrogens. 2. Blood urea and creatinine levels before and after gentamicin administration were measured to evaluate renal function. Histological lesions were studied by light microscopy by two pathologists who were unaware of the group. Rats with normal or elevated levels of estrogens showed functional impairment after gentamicin. A poor correlation was detected between levels of urea/creatinine and histopathological findings. 3. Lesions were considerably more severe in females. Testosterone administration to intact animals offered partial protection against the renal effects of gentamicin in both sexes. In contrast, estradiol administered to intact animals was regularly associated with significantly more severe lesions in both males and females. Castration by itself attenuated the gentamicin-induced renal alterations in males, but not in females. These data provide support for an unfavorable effect of estrogens rather than a favorable effect of testosterone. The demonstration of more severe lesions in female castrated rats when compared with male castrated rats indicates the participation of other factors, possibly of a genetic nature, in the pathogenesis of gentamicin-induced renal lesions.