Use of protein:creatinine ratio measurements on random urine samples for prediction of significant proteinuria: a systematic review

Accuracy of spot urine protein creatinine ratio in measuring proteinuria in chronic kidney disease stage 3 and 4

We studied the accuracy of spot urine protein creatinine ratio (SpUr-PCR) to assess 24 h urine protein excretion (24 h-UP) in patients with chronic kidney disease (CKD). A total of 100 proteinuric CKD patients of stages 3 and 4 were studied. 24 h urine was collected to measure 24 h-UP and creatinine. A random day time urine sample was analyzed to measure the PCR. A formula to estimate 24 h creatinine excretion was derived from linear regression analysis and a correction factor was introduced to assess whether this improves the accuracy of the SpUr PCR in predicting 24 h-UP. Accuracy of the SpUr-PCR was assessed by Pearson's correlation, regression analysis, and Bland Altman analysis. Mean age was 51.85 ± 12 years and 81% of the patients were male. SpUr-PCR predicted 24 h-UP with good accuracy (r = 0.86 on a data transformed to a logarithmic scale, P < 0.001) and there was a good agreement between these two measures of proteinuria. However, SpUr-PCR was inaccurate in the subgroup with nephrotic range proteinuria (r = 0.35, P = 0.062), but when a correction factor for 24-h urine creatinine (24 h-UCr) was introduced, the accuracy of SpUr-PCR improved significantly in this group (r = 0.45, P = 0.013). Introduction of the correction factor improved the degree of agreement between these two measures in women, but not the correlation. Overall, SpUr-PCR accurately predicted 24 h-UP. Adding a correction factor for 24 h-UCr improved correlation in the subgroup of patients with the nephrotic range proteinuria and the degree of agreement in female patients, and hence may be used in expressing proteinuria measured by SpUr-PCR to improve its accuracy in them.

Quantitative Micro-albuminuria Assessment from 'Random Voided Urinary Albumin: Creatinine Ratio' Versus '24 hours Urinary Albumin Concentration' for Screening of Diabetic Nephropathy

AIMS

This study aims at assessing the predictive value of random urine A:C ratio as a screening method for Micro-albuminuria assessment in DM patients as compared to 24 hours urine albumin.

SETTINGS AND DESIGN

A cross sectional observational study was conducted at a tertiary care centre. One hundred ninty three patients diagnosed with DM were enrolled in the study but 14 participants didn't turn up with 24 hours urine sample. Thus, 179 people actually participated in the study.

MATERIAL AND METHODS

All DM patients who attended Out Patient Departments (OPDs) and In Patient Departments (IPDs) of Medicine, Surgery and Orthopaedics, were enrolled. Proper history about development and duration of DM was taken from the patients. Examination in the form of height and weight measurement to know Body Mass Index (BMI), the Waist: Hip Ratio (W:H ratio) calculated from waist and hip circumference and blood pressure measurement was done. Fasting blood sugar was measured in the study group. [Urine analysis was done for urinary albumin and urinary creatinine]. Two urine samples were collected from each participant; one, 24 hours sample and the other random urine sample. 24 hours urine samples were used to measure urinary albumin concentration while urinary albumin to creatinine ratio was measured from random urine sample.

STATISTICAL ANALYSIS USED

SPSS 17.

RESULTS

Twenty four hours RUA:C ratio has very good sensitivity and specificity of Sensitivity and specificity of 84.9% and 95.8% respectively,which makes it a better alternative to 24 hours UAC. Negative and positive predictive values of RUA:C ratio method are 0.93 and 0.090 respectively with false negative and false positive rates, 15.1% and 4.2 % respectively.

CONCLUSION

Twenty four hours UAC is considered gold standard for screening of Micro-albuminuria but is cumbersome to collect 24 hours urine sample especially in OPD setup and in female patients. This leads to loss of compliance thereby preventing early diagnosis of diabetic nephropathy. This problem is more impracticable in hilly regions of India. By using random urine sample for screening of Micro-albuminuria in the form of RUA: C in random urine sample that correlates well with 24 hours UAC in 24 hours urine sample,is easier and more practical in Indian scenario especially in diabetics residing in hills.

Clinicopathological findings in non-human primate recipients of porcine renal xenografts: quantitative and qualitative evaluation of proteinuria

BACKGROUND

Immunological and histopathological features in pig-to-primate renal xenotransplantation are widely studied. Only limited data have been reported about clinicopathological findings in primate recipients of life-supporting renal xenografts. In human medicine, proteinuria represents a common complication in kidney transplantation and is associated with impaired graft survival. The detection of low molecular weight proteins of tubular origin is considered an early method for predicting potential graft rejection. In this study, the presence and the significance of quantitative and qualitative proteinuria were evaluated in xenotransplanted non-human primates in which kidney function was supported only by the transplanted organ.

METHODS

Eight bilaterally nephrectomized cynomolgus monkeys (Macaca fascicularis) were transplanted with a single kidney from α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for human CD39, CD55, CD59, and α1,2-fucosyltransferase. In addition to hematological and biochemical analyses, quantitative and qualitative analysis of proteinuria was evaluated by urinary protein-to-creatinine ratio (UPC ratio) and sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE), respectively.

RESULTS

The main hematological and biochemical changes recorded after transplantation were a progressive anemia and a severe and progressive decrease in total proteins. In urine samples, the UPC ratio was low before transplantation and increased after transplantation. Similarly, SDS-AGE was negative before transplantation, but bands consistent with mixed (i.e., tubular and glomerular) proteinuria were observed in all samples collected post-transplantation.

CONCLUSIONS

The study of clinicopathological changes in cynomolgus monkey renal xenograft recipients provides a valid help in monitoring the health conditions in the post-transplant period. Moreover, the evaluation of UPC ratio and the use of SDS-AGE technique in urine samples of cynomolgus monkey renal xenograft recipients may be considered a valid, inexpensive, and less time-consuming method than more sophisticated techniques in monitoring proteinuria. Proteinuria and presence of low molecular weight (LMW) proteins were consistently found in urine after transplantation, independent of fluctuations in renal function.

Organic anion transporter 5 renal expression and urinary excretion in rats with vascular calcification

It has been described renal damage in rats with vascular calcification. The organic anion transporter 5 (Oat5) is only expressed in kidney, and its urinary excretion was proposed as potential early biomarker of renal injury. The aim of this study was to evaluate the Oat5 renal expression and its urinary excretion in an experimental model of vascular calcification in comparison with traditional markers of renal injury. Vascular calcification was obtained by the administration of an overdose of vitamin D₃ (300,000 IU/kg, b.w., i.m.) to male Wistar rats. Oat5 urinary abundance was evaluated by Western blotting. Traditional markers of renal injury, such as creatinine and urea plasma levels, urinary protein levels, and urinary alkaline phosphatase (AP) activity, were determined using commercial kits. Histology was assessed by hematoxylin/eosin staining. Oat5 renal expression was evaluated by Western blotting and by immunohistochemistry. An increased expression of Oat5 in renal homogenates, in apical membranes, and in its urinary excretion was observed in rats with vascular calcification. The traditional parameters used to evaluate renal function were not modified, with the exception of histology. It is possible to postulate the urinary excretion of Oat5 as a potential noninvasive biomarker of renal injury associated with vascular calcification.

Measurement of renal function in patients with chronic kidney disease

Chronic kidney disease affects millions of people worldwide and is associated with an increased morbidity and mortality as a result of kidney failure and cardiovascular disease. Accurate assessment of kidney function is important in the clinical setting as a screening tool and for monitoring disease progression and guiding prognosis. In clinical research, the development of new methods to measure kidney function accurately is important in the search for new therapeutic targets and the discovery of novel biomarkers to aid early identification of kidney injury. This review considers different methods for measuring kidney function and their contribution to the improvement of detection, monitoring and treatment of chronic kidney disease.

Random spot urine protein/creatinine ratio: a reliable method for monitoring lupus nephritis?

Background

Lupus nephritis (LN) is a common and severe manifestation of systemic lupus erythematosus (SLE) that can lead to end-stage renal disease. According to the Kidney Disease Outcomes Global Improving clinical Guidelines for Glomerulonephritis, spot urine protein/creatinine (P/C) ratio should be used for monitoring LN. However, some reports write that the random spot urine P/C ratio is unreliable in monitoring proteinuria in SLE glomerulonephritis patients. The aim of this study was to evaluate the agreement of these two assay methods.

Methods

The prospective observational study was performed. Fifty-three paired (total 106) spot and 24-h urine collections were evaluated. Statistical analysis: SPSS 20.0.

Results

Paired samples t-test did not reveal significant differences between the two-paired assay methods (spot P/C ratio versus 24-h proteinuria and 24-h P/C ratio) and a statistically significant correlation was observed between them: Pearson's coefficient of 0.847 (P < 0.001) and 0.863 (P < 0.001), respectively. However, after stratifying by degrees of proteinuria, a poor correlation was found in the range of <500 mg/day and only 26.6% of 24-h P/C ratio was explained by the spot P/C ratio. Adding to this, for proteinuria range between 500 and 1000 mg/day, there was no correlation (Pearson's −0.098; P > 0.05). In fact, only 1% of 24-h measurements could be explained by the spot P/C ratio.

Conclusions

Our study demonstrated a good correlation between 24-h proteinuria and random P/C ratio among patients with LN. However, this correlation was poor for proteinuria under 500 mg/day and did not exist in a range between 500 and 1000 mg/day. This finding is of greater importance because this range is quite common in patients with LN remission. Until further clarification, to the best of our knowledge, we maintain reluctant to completely substitute the 24-h collection by the P/C ratio especially when a renal flare is suspected, or before any change in therapy.

Detection of proteinuria in pregnancy: comparison of qualitative tests for proteins and dipsticks with urinary protein creatinine index

BACKGROUND AND OBJECTIVES

Excretion of urinary protein increases to 300 mg/d (from up to 150 mg/d) in normal pregnancy. Values above this may be due to disorders that can endanger the patient or her pregnancy. Quantitative analysis of 24-hour urine is considered the gold standard for ascertaining daily protein excretion. Routine laboratory tests performed on spot urine samples indicate protein concentration in the particular sample, and can lead to diagnostic error if urine output is less or more than 1L/d. The Protein Creatinine Index (PCI) shows good correlation with 24-hour protein estimation. However, PCI varies with sex and race. We have correlated the results of qualitative estimation procedures and the dipstick values with protein creatinine index.

MATERIAL AND METHODS

We measured protein and creatinine in spot urine samples obtained from 57 pregnant and 80 non-pregnant healthy women of 18-36 years, and calculated PCI. We also tested the samples qualitatively for proteins by routine tests and dipsticks.

RESULTS

Normal range of PCI in non-pregnant women, determined by a non-parametric method was 30-150. PCI was increased significantly in pregnancy (maximum increase in the third trimester). Amongst the qualitative tests, heat coagulation test gave the lowest percentage of false positives and a slightly higher percentage of false negatives compared to Heller's nitric acid and sulphosalicylic acid tests, and dipsticks.

INTERPRETATIONS AND CONCLUSIONS

We conclude that heat coagulation test be used for initial screening, with PCI being performed on all samples testing positive to rule out false positives.

Renal function following three distinct weight loss dietary strategies during 2 years of a randomized controlled trial

OBJECTIVE

This study addressed the long-term effect of various diets, particularly low-carbohydrate high-protein, on renal function on participants with or without type 2 diabetes.

RESEARCH DESIGN AND METHODS

In the 2-year Dietary Intervention Randomized Controlled Trial (DIRECT), 318 participants (age, 51 years; 86% men; BMI, 31 kg/m(2); mean estimated glomerular filtration rate [eGFR], 70.5 mL/min/1.73 m(2); mean urine microalbumin-to-creatinine ratio, 12:12) with serum creatinine <176 μmol/L (eGFR ≥ 30 mL/min/1.73 m(2)) were randomized to low-fat, Mediterranean, or low-carbohydrate diets. The 2-year compliance was 85%, and the proportion of protein intake significantly increased to 22% of energy only in the low-carbohydrate diet (P < 0.05 vs. low-fat and Mediterranean). We examined changes in urinary microalbumin and eGFR, estimated by Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration formulas.

RESULTS

Significant (P < 0.05 within groups) improvements in eGFR were achieved in low-carbohydrate (+5.3% [95% CI 2.1-8.5]), Mediterranean (+5.2% [3.0-7.4]), and low-fat diets (+4.0% [0.9-7.1]) with similar magnitude (P > 0.05) across diet groups. The increased eGFR was at least as prominent in participants with (+6.7%) or without (+4.5%) type 2 diabetes or those with lower baseline renal function of eGFR <60 mL/min/1.73 m(2) (+7.1%) versus eGFR ≥ 60 mL/min/1.73 m(2) (+3.7%). In a multivariable model adjusted for age, sex, diet group, type 2 diabetes, use of ACE inhibitors, 2-year weight loss, and change in protein intake (confounders and univariate predictors), only a decrease in fasting insulin (β = -0.211; P = 0.004) and systolic blood pressure (β = -0.25; P < 0.001) were independently associated with increased eGFR. The urine microalbumin-to-creatinine ratio improved similarly across the diets, particularly among participants with baseline sex-adjusted microalbuminuria, with a mean change of -24.8 (P < 0.05).

CONCLUSIONS

A low-carbohydrate diet is as safe as Mediterranean or low-fat diets in preserving/improving renal function among moderately obese participants with or without type 2 diabetes, with baseline serum creatinine <176 μmol/L. Potential improvement is likely to be mediated by weight loss-induced improvements in insulin sensitivity and blood pressure.

Empiricism or rationalism: how should we measure proteinuria?

Proteinuria is the cardinal sign of renal disease, therefore accurate identification of clinically significant proteinuria is essential to the diagnosis and management of kidney disease. Spot samples are now widely used, namely protein: creatinine ratio (uPCR) and albumin: creatinine ratio (uACR). In this article we review the evidence comparing uPCR and uACR including clinical, laboratory and financial arguments.

uPCR has a superior performance to uACR to predict 24-hour total proteinuria, the measurement on which the evidence for interventions in chronic kidney disease is based. Furthermore a retrospective study comparing uPCR and uACR as predictors of renal outcome found comparable performance to predict all-cause mortality, commencement of renal replacement therapy and doubling of serum creatinine. Only uPCR takes account of non-albumin proteinuria which has been shown to have prognostic significance. uACR was been thought to be superior at low levels (where there is less ‘noise’ from physiological urinary proteins), but uPCR has recently been shown to perform well at levels equivalent to <0.5 g/day (and even within the reference range) as a predictor of outcomes. uACR is measured using an immunoassay that may be technically superior, but is not without shortcomings (such as antigen excess) and is 2–10 times more expensive than uPCR.

The theories explaining the superiority of albumin are appealing. However, the available comparative data do not seem to support the theory. We cannot explain the disparity, but in science, if the data do not fit the existing theory, then maybe it's time for a new theory.

Comparison of urinary protein: creatinine index and dipsticks for detection of microproteinuria in diabetes mellitus patients

BACKGROUND

Proteinuria has been recognized as one of the earliest signs of renal function deterioration in Diabetes mellitus. Proteinuria occurs due to alterations in the glomerular permeability and later, due to a failure in the reabsorption of filtered protein by the tubular cells. Normally, most of the healthy adults excrete 20-150 mg of protein in urine over 24 hours.

OBJECTIVES

To find out the normal urinary Protein Creatinine Index (PCI) in healthy subjects, to compare the urinary PCI of diabetic patients with that of healthy subjects and to compare the urinary PCI with dipsticks for the detection of microproteinuria.

MATERIAL AND METHODS

This study was conducted on 28 type 2 Diabetes mellitus patients and 40 age and sex matched healthy controls. Freshly collected urine samples were tested qualitatively for the presence of proteinuria by Heller's test, the sulfosalicylic acid test, heat-coagulation tests and urine dipsticks. Later on, the results were compared by performing a quantitative analysis of the protein in the spot urine samples by the sulfosalicylic acid method. A quantitative analysis of creatinine was done by the modified Jaffe's test. The PCI was calculated for each of the participant in the study. The Mean and Standard Deviation (SD) of the PCI was calculated and it was compared between the two groups.

RESULTS

The normal range of the PCI which was established in this study was 60 to 220. Significantly higher amount of proteins were found to be excreted in urine in diabetic patients (25.37 ± 12.51 mg/dl) as compared to those in normal subjects (8.93 ± 3.54 mg/dl). On comparison of the PCI between the controls and the diabetic subjects, it was found to be significantly elevated in the Diabetes mellitus patients (controls = 114.65 ±47.97 and in the diabetic patients =373.04 ± 98.53) (p < 0.001).

CONCLUSION

The PCI of a random urine sample can provide a very useful, simple and convenient method for the quantitative assessment of proteinuria, to judge the extent of kidney damage and for avoiding the drawbacks of the 24 - hr urine collections.

Pregnancy-Associated Kidney Injury

A 23-year-old G1P0000 without prior past medical history is 31 weeks pregnant with prenatal care presents with complaints of worsening leg and face swelling for the past 2 days now seeks care because of headache, diarrhea, nausea, and vomiting. On exam she is found to have a blood pressure of 120/86, edema, and brisk deep tendon reflexes. Laboratory testing revealed hemoglobin 11.3 g/dl, platelet count 141,000/μl white blood count 18,000/μl, creatinine 1.1 mg/dl, aspartate aminotransferases (AST) 65 U/l, lactate dehydrogenase (LDH) 400 U/l, total bilirubin 1.1 mg/dl, prothrombin time (PT) 14.7 s, ammonia of 90 mcg/dl, blood glucose 139 mg/dl, calcium 7.3 mg/dl, and uric acid of 6.0 mg/dl. The urinalysis demonstrated WBC’s 3–5/hpf, RBC’s 3–5/hpf—non-dysmorphic, renal tubular epithelial cells were seen and a urine protein to creatinine ratio of 2. One day after hospitalization the patient’s blood pressure was 145/87 with a similar blood pressure 6 h later.

Chronic kidney disease and measurement of albuminuria or proteinuria: a position statement

Optimal detection and subsequent risk stratification of people with chronic kidney disease (CKD) requires simultaneous consideration of both kidney function (glomerular filtration rate [GFR]) and kidney damage (as indicated by albuminuria or proteinuria). Measurement of urinary albuminuria and proteinuria is hindered by a lack of standardisation regarding requesting, sample collection, reporting and interpretation of tests. A multidisciplinary working group was convened with the goal of developing and promoting recommendations that achieve consensus on these issues. The working group recommended that the preferred method for assessment of albuminuria in both diabetic and non-diabetic patients is urinary albumin-to-creatinine ratio (UACR) measurement in a first-void spot urine specimen. Where a first-void specimen is not possible or practical, a random spot urine specimen for UACR is acceptable. The working group recommended that adults with one or more risk factors for CKD should be assessed using UACR and estimated GFR every 1-2 years, depending on their risk-factor profile. Recommended testing algorithms and sex-specific cut-points for microalbuminuria and macroalbuminuria are provided. The working group recommended that all pathology laboratories in Australia should implement the relevant recommendations as a vital component of an integrated national approach to detection of CKD.

The effect of exercise on urinary gamma-glutamyltransferase and protein levels in elite female karate athletes

PURPOSE

Post exercise proteinuria and increased urinary Gamma-Glutamyl transferase (GGT) levels can be indicative of exercise-induced renal damage. The aim of this investigation is to study the effect of one session of intensive training on renal damage markers and compare their values to those 6 hours after training.

METHODS

In this cross-sectional study with pre- and post-test design, 10 elite volunteer female athletes were selected and participated in one training session (2 hours). Urine samples were collected before training, one hour after training, and 6 hours after training. Urinary protein (Pr), creatinine (Cr), and GGT values were measured through laboratory methods and then Pr/Cr and GGT/Cr ratios were computed.

RESULTS

There were significant differences between values of protein, GGT and Creatinine in the three sampling phases (P<0.05). However, no significant differences were observed between values for GGT/Cr and Pr/Cr ratio. There were significant differences between the mean values of Creatinine, protein and GGT within pre-exercise and 1 hour post-exercise and within 1 hour post-exercise and 6 hours post-exercise (P<0.05).

CONCLUSION

It seems that a session of karate training does not result in renal damage and athletes can continue training after 6 hours.

Prevalence and risk factors for diabetic maculopathy, and its relationship to diabetic retinopathy in elderly Japanese patients with type 2 diabetes mellitus

AIMS

To determine the prevalence of diabetic retinopathy and diabetic maculopathy in Japanese patients older than 65 years-of-age with type 2 diabetes mellitus. In addition, to determine the relationship between the severity of retinopathy and maculopathy, and the risk factors for these conditions in Japanese patients with the same characteristics.

METHODS

This was a cross-sectional study carried out at the enrolment of patients who participated in a randomized controlled trial. A total of 960 eyes of 960 Japanese patients with type 2 diabetes who were ≥ 65 years-of-age were analyzed.

RESULTS

Our data showed that there was a correlation between the severity of retinopathy and the severity of maculopathy. The risk factors for the severity of retinopathy were different from the risk factors for the severity of maculopathy. The age, duration of diabetes, systemic pulse pressure, fasting insulin, insulin treatment of diabetes, high-density lipoprotein cholesterol, microalbumin-to-creatinine ratio and history of cerebrovascular disease all contributed significantly to the severity of retinopathy. The duration of diabetes, insulin treatment and microalbumin-to-creatinine ratio were correlated with the severity of maculopathy.

CONCLUSIONS

The risk factors related to diabetic retinopathy and maculopathy in Japanese patients with type 2 diabetes mellitus aged ≥ 65 years were different from that in other countries. Our data also showed that the certain risk factors for retinopathy differ from those associated with maculopathy.

Proteinuria in the elderly: evaluation and management

While aging is accompanied by many age-related changes in renal physiology and function, proteinuria should not be considered to be a part of "normal aging". There are many age-prevalent illnesses that predispose one to developing proteinuria and early recognition, and treatment may help retard disease progression or offer an early cure. The presence of proteinuria warrants further evaluation and follow-up if one has any hope of avoiding its progression and delaying the initiation of treatment. This review article will discuss the anatomy and physiology of the aging kidney, the pathophysiology and etiology of proteinuria during later life, methods to evaluate proteinuria, and ways to monitor and manage this problem.

Highlights for the management of a child with proteinuria and hematuria

The identification of hematuria or proteinuria in an otherwise healthy child can cause anxiety to both the family and the pediatrician. The etiology of hematuria and proteinuria includes a long list of conditions, and detailed workup can be exhaustive, expensive and not essential in most of the patients. As will be described in this paper, most of the children with proteinuria or hematuria have a benign etiology. The primary role of the pediatrician is to identify hematuria/proteinuria, recognize the common causes of hematuria/proteinuria, and more importantly identify children with serious conditions that need referral to the nephrologist in a timely manner.

A comprehensive review of hypertension in pregnancy

Hypertension is the most common medical disorder encountered during pregnancy. Hypertensive disorders are one of the major causes of pregnancy-related maternal deaths in the United States. We will present a comprehensive update of the literature pertinent to hypertension in pregnancy. The paper begins by defining and classifying hypertensive disorders in pregnancy. The normal vascular and renal physiological changes which occur during pregnancy are detailed. We will summarize the intriguing aspects of pathophysiology of preeclampsia, emphasizing on recent advances in this field. The existing diagnostic tools and the tests which have been proposed for screening preeclampsia are comprehensively described. We also highlight the short- and long-term implications of preeclampsia. Finally, we review the current management guidelines, goals of treatment and describe the potential risks and benefits associated with various antihypertensive drug classes. Preeclampsia still remains an enigma, and the present management focuses on monitoring and treatment of its manifestations. We are hopeful that this in depth critique will stimulate the blossoming research in the field and assist practitioners to identify women at risk and more effectively treat affected individuals.

Fibroblast growth factor 23 is associated with proteinuria and smoking in chronic kidney disease: an analysis of the MASTERPLAN cohort

BACKGROUND

Fibroblast growth factor 23 (FGF23) has emerged as a risk factor for cardiovascular disease and mortality throughout all stages of chronic kidney disease (CKD), independent from established risk factors and markers of mineral homeostasis. The relation of FGF23 with other renal and non-renal cardiovascular risk factors is not well established.

METHODS

Using stored samples, plasma FGF23 was determined in 604 patients with moderate to severe kidney disease that participated in the MASTERPLAN study (ISRCTN73187232). The association of FGF23 with demographic and clinical parameters was evaluated using multivariable regression models.

RESULTS

Mean age in the study population was 60 years and eGFR was 37 (± 14) ml/min/1.73 m(2). Median proteinuria was 0.3 g/24 hours [IQR 0.1-0.9]. FGF23 level was 116 RU/ml [67-203] median and IQR. Using multivariable analysis the natural logarithm of FGF23 was positively associated with history of cardiovascular disease (B = 0.224 RU/ml; p = 0.002), presence of diabetes (B = 0.159 RU/ml; p = 0.035), smoking (B = 0.313 RU/ml; p < 0.001), phosphate level (B = 0.297 per mmol/l; p = 0.0024), lnPTH (B = 0.244 per pmol/l; p < 0.001) and proteinuria (B = 0.064 per gram/24 hrs; p = 0.002) and negatively associated with eGFR (B = -0.022 per ml/min/1.73 m(2); p < 0.001).

CONCLUSIONS

Our study demonstrates that in patients with CKD, FGF23 is related to proteinuria and smoking. We confirm the relation between FGF23 and other cardiovascular risk factors.

What is the best method of proteinuria measurement in clinical trials of endothelin receptor antagonists?

AIMS

To determine whether protein-creatinine ratio (PCR) and albumin-creatinine ratio (ACR) are comparable to 24h urine protein in terms of agreement and repeatability, and therefore whether they are suitable for monitoring and comparing reduction in proteinuria in clinical trials of endothelin receptor antagonists.

MAIN METHODS

Using data from a recent study of sitaxentan in 27 patients with proteinuric chronic kidney disease, the assays were compared with reference to their agreement, repeatability, the number of measurements required to obtain accurate results and correlation with reduction in proteinuria at baseline.

KEY FINDINGS

The median coefficient of variation was lower for PCR than 24h urine protein (25 vs. 28%) but the range was higher (70 vs. 47%). When converted into the same units, mean difference between 24h urine protein and both PCR (0.03 g/day), and ACR (0.10 g/day), was small. However, scatter increased with mean level of proteinuria, such that agreement fell substantially above 1.5 g/day. According to 2-factor within-subjects ANOVA, the assay used was not a significant source of variation (PCR p=0.63, ACR p=0.38). With 3 measurements at each time point, baseline proteinuria correlated equally well with change in proteinuria, and percentage change was detected accurately by all 3 methods.

SIGNIFICANCE

PCR and ACR may well be suitable replacements for 24h urine protein in the clinical trial context due to their similar accuracy and repeatability, greater convenience and lower cost. However, a randomised control trial comparing all 3 assays in a larger and more diverse population is necessary before 24h urine protein can be replaced.

Renal evaluation in women with preeclampsia

BACKGROUND/AIMS

Preeclampsia (PE) is a cause of glomerulopathy worldwide. Urinary retinol-binding protein (RBP) is a marker of proximal tubular dysfunction, albuminuria is an endothelial injury marker, urine protein:creatinine ratio (PCR) may have a predictive value for renal disease later in life, and, recently, podocyturia has been proposed as a sensitive tool in pregnancy, but it needs to be tested. The aim of this study was to evaluate renal involvement in PE and healthy pregnancy.

METHODS

Case-control study with 39 pregnant women assessed after 20 weeks of gestation (25 in the control group, CG, and 14 in the PE group) by performing urinary tests.

RESULTS

Mean (±SD) age and gestational age of the CG were 26.9 ± 6.4 years and 37.1 ± 5.0 weeks, and of the PE group 26.4 ± 6.9 years and 30.6 ± 5.6 weeks, respectively (p = 0.001). Mean (±SD) urinary RBP (p = 0.017), albuminuria (p = 0.002), and urinary albumin concentration (UAC) ratio (p = 0.006) of the CG were 0.4 ± 0.7 mg/l, 7.3 ± 6.9 mg/l, and 8.2 ± 6.7 mg/g and of the PE group 2.0 ± 4.4 mg/l, 2,267.4 ± 2,130.8 mg/l (p = 0.002), and 3,778.9 ± 4,296.6 mg/g (p = 0.006), respectively. Mean (±SD) urine PCR in the PE group was 6.7 ± 6.1 g/g (p < 0.001). No statistical differences were found between podocyturia in the CG and PE group (p = 0.258).

CONCLUSIONS

Urinary RBP, PCR, albuminuria, and UAC ratio were elevated in the PE group in comparison to the CG. Podocyturia did not predict PE.

Maternal plasma concentrations of angiogenic/anti-angiogenic factors are of prognostic value in patients presenting to the obstetrical triage area with the suspicion of preeclampsia

OBJECTIVE

To determine whether maternal plasma concentrations of placental growth factor (PlGF), soluble endoglin (sEng), soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and -2 could identify patients at risk for developing preeclampsia (PE) requiring preterm delivery.

STUDY DESIGN

Patients presenting with the diagnosis "rule out PE" to the obstetrical triage area of our hospital at <37 weeks of gestation (n = 87) were included in this study. Delivery outcomes were used to classify patients into four groups: I) patients without PE or those with gestational hypertension (GHTN) or chronic hypertension (CHTN) who subsequently developed PE at term (n = 19); II): mild PE who delivered at term (n = 15); III): mild disease (mild PE, GHTN, CHTN) who subsequently developed severe PE requiring preterm delivery (n = 26); and IV): diagnosis of severe PE (n = 27). Plasma concentrations of PlGF, sEng, sVEGFR-1 and -2 were determined at the time of presentation by ELISA. Reference ranges for analytes were constructed by quantile regression in our laboratory (n = 180; 1046 samples). Comparisons among groups were performed using multiples of the median (MoM) and parametric statistics after log transformation. Receiver operating characteristic curves, logistic regression and survival analysis were employed for analysis.

RESULTS

The mean MoM plasma concentration of PlGF/sVEGFR-1, PlGF/sEng, PlGF, sVEGFR-1 and -2, and sEng in Group III was significantly different from Group II (all p < 0.05). A plasma concentration of PlGF/sVEGFR-1 ≤ 0.05 MoM or PlGF/sEng ≤0.07 MoM had the highest likelihood ratio of a positive test (8.3, 95% CI 2.8-25 and 8.6, 95% CI 2.9-25, respectively), while that of PlGF ≤0.396 MoM had the lowest likelihood ratio of a negative test (0.08, 95% CI 0.03-0.25). The association between low plasma concentrations of PlGF/sVEGFR-1 (≤0.05 MoM) as well as that of PlGF/sEng (≤0.07 MoM) and the development of severe PE remained significant after adjusting for gestational age at presentation, average systolic and diastolic blood pressure, and a history of chronic hypertension [adjusted odds ratio (OR) = 27 (95% CI 6.4-109) and adjusted OR 30 (95% CI 6.9-126), respectively]. Among patients who presented <34 weeks gestation (n = 59), a plasma concentration of PlGF/sVEGFR-1 < 0.033 MoM identified patients who delivered within 2 weeks because of PE with a sensitivity of 93% (25/27) and a specificity of 78% (25/32). This cut-off was associated with a shorter interval-to-delivery due to PE [hazard ratio = 6 (95% CI 2.5-14.6)].

CONCLUSIONS

Plasma concentrations of angiogenic/anti-angiogenic factors are of prognostic value in the obstetrical triage area. These observations support the value of these biomarkers in the clinical setting for the identification of the patient at risk for disease progression requiring preterm delivery.

Twenty-four-hour Bence-Jones protein determinations: can we ensure accuracy?

CONTEXT

Light chain disease represents 15% to 20% of cases of multiple myeloma. Current guidelines recommend monitoring these patients with 24-hour urine collections.

OBJECTIVE

To determine the reliability of 24-hour urine collections in assessing the amount of Bence-Jones protein (BJP).

DESIGN

We included all patients from our institution from 2003 through 2008 with BJP who had more than four 24-hour urine collections. We compared BJP excretion calculated from the submitted 24-hour collection with BJP excretion calculated by normalizing the collection to that patient's mean 24-hour creatinine excretion. We also looked at differences in serial values with these 2 methods. In addition, we evaluated the feasibility of using random urine samples to determine BJP excretion.

RESULTS

A total of 14 patients with 135 24-hour urine collections met our inclusion criteria. The 24-hour urine creatinine excretion for each patient, which should be reasonably constant, varied considerably (coefficient of variation range 12%-30%). Differences in the 2 methods of calculating BJP excretion ranged from -1588 to 2315 mg/d. Among a total of 121 serial 24-hour measurements, the differences were clinically significant in 37 (30%). Among a total of 23 random urine samples from 11 of these patients submitted within 10 days of a 24-hour collection, the estimated BJP excretion appeared to be accurate in at least 18 (78%).

CONCLUSIONS

Twenty-four-hour urine collections for BJP are, in practice, often misleading. At a minimum, one should verify that the 24-hour creatinine excretion is accurate. In addition, it may be possible to use the protein/creatinine ratio from random urine samples to determine 24-hour BJP excretion.

Evaluation of Aution Max AX-4030 and 9UB Uriflet, 10PA Aution Sticks urine dipsticks in the automated urine test strip analysis

BACKGROUND

Aution Max AX-4030, a test strip analyzer recently introduced to the market, represents an upgrade of the Aution Max AX-4280 widely employed for urinalysis. This new instrument model can allocate two different test strips at the same time. In the present study the two instruments have been compared together with the usage of Uriflet 9UB and the recently produced Aution Sticks 10PA urine strips, the latter presenting an additional test area for the measurement of urinary creatinine.

METHODS

Imprecision and correlation between instruments and strips have been evaluated for chemical-physical parameters. Accuracy was evaluated for protein, glucose and creatinine by comparing the semi-quantitative results to those obtained by quantitative methods. The well-known interference effect of high ascorbic acid levels on urine glucose test strip determination was evaluated, ascorbic acid influence was also evaluated on protein and creatinine determination.

RESULTS

The two instruments have demonstrated comparable performances: precision and correlation between instruments and strips, evaluated for chemical-physical parameters, were always good. Furthermore, accuracy was always very good: results of protein and glucose semi-quantitative measurements resulted to be highly correlated with those obtained by quantitative methods. Moreover, the semi-quantitative measurements of creatinine, employing Aution Sticks 10PA urine strips, were highly comparable with quantitative results.

CONCLUSIONS

10PA urine strips are eligible for urine creatinine determination with the possibility of correcting urinalysis results for urinary creatinine concentration, whenever necessary and calculating the protein creatinine ratio. Further studies should be carried out to evaluate effectiveness and appropriateness of the usage of creatinine semi-quantitative analysis.

The characteristics of new semi-quantitative method for diagnosing proteinuria by using random urine samples

We assessed the characteristics of the new semi-quantitative test paper (Clinitek ATLAS Pro(12)) using random urine samples. Three hundred urine samples were analyzed using either the new test paper, conventional dipsticks, quantitative (P/C ratio), or immunological quantitative methods (A/C ratio). Our study showed that the new test paper is highly sensitive and specific for the detection of urinary protein. The new test paper also detected the urine protein more accurately than the conventional test and has a lower false-positive rate. In addition, the new test paper detected 14 of the 300 patients (4.7%) as dilute urine samples needing reassessment. Seventeen of the 300 samples tested were negative with conventional dipsticks but positive with the new test paper. The new semi-quantitative test paper not only has higher sensitivity than the conventional dipstick method, but also has potential to detect dilute samples.

Protein/creatinine ratio on random urine samples for prediction of proteinuria in preeclampsia

OBJECTIVE

To evaluate Protein/Creatinine ratio on random urine samples for prediction of proteinuria in preeclampsia.

MATERIALS AND METHODS

This study was performed on 150 pregnant women who were hospitalized as preeclampsia in Ghaem Hospital during 2006. At first, a 24-hours urine sample was collected for each patient to determine protein/creatinine ratio. Then, 24-hours urine collection was analyzed for the evaluation of proteinuria. Statistical analysis was performed with SPSS software.

RESULTS

A total of 150 patients entered the study. There was a significant relation between the 24-hours urine protein and protein/creatinine ratio (r = 0.659, P < 0.001).

CONCLUSION

Since the measurement of protein/creatinine ratio is more accurate, reliable, and cost-effective, it can be replaced by the method of measurement the 24-hours urine protein.

Protein:creatinine ratio in uncomplicated twin pregnancy

OBJECTIVE

Women with twin pregnancies may have higher rates of isolated proteinuria than do those with singletons. We compared protein-to-creatinine (P:C) ratios longitudinally through gestation in uncomplicated twin and singleton pregnancies.

STUDY DESIGN

P:C ratios were compared at 3 times points in 102 (51 twins, 51 singletons) healthy gravid patients who did not have preeclampsia develop, using linear and logistic regression techniques.

RESULTS

P:C ratio increased significantly over gestation in all patients. This increase was significantly greater in twins than in singletons. The odds of P:C ratio >0.19 was 3.5 times higher in twins between 34 and 38 weeks.

CONCLUSION

Women with uncomplicated twin pregnancies have greater protein excretion as measured by P:C ratios than do those with singletons. In early pregnancy, protein excretion is similar, but it diverges significantly by the latter third trimester. We suggest that normal values for proteinuria in twins may differ from those in singletons, and warrant further evaluation.

Spontaneous remission of nephrotic syndrome in patients with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) can be complicated by nephrotic syndrome. Because the spontaneous resolution of heavy proteinuria is rare, corticosteroid therapy should be considered in such cases, particularly when IgAN is combined with minimal-change disease. Here, we report our experience of spontaneous remission of nephrotic syndrome in patients with IgAN and the long-term outcomes of these patients.

METHODS

Two hundred and thirty-three patients with biopsy-proven IgAN were enrolled between January 2001 and March 2009. Demographic, clinical and laboratory data were collected retrospectively based on medical records. In addition, pathologic findings were reviewed for glomerular and tubulointerstitial lesions. Outcome data for complete or partial remission, spontaneous remission, relapse, deterioration of renal function, and end-stage renal disease were recorded.

RESULTS

Twenty-four patients (10.3%) presented nephrotic syndrome. Among them, five patients underwent spontaneous remission within 6 months after the presentation of nephrotic syndrome. Interestingly, spontaneous remission occurred even in two patients who had elevated serum creatinine levels and advanced renal damage. During follow-up, neither recurrence nor relapse occurred, and no patients showed progressive deterioration of kidney function. Conclusions. This study suggests that spontaneous remission of nephrotic syndrome may occur in any stage of IgAN and carries a favourable long-term outcome without relapse. Given the possibility of under-reported cases, large-scale studies are required, and careful attention should be paid to such complicated cases.

Correlation of random urine protein creatinine (P-C) ratio with 24-hour urine protein and P-C ratio, based on physical activity: a pilot study

Quantification of proteinuria is usually predicated upon 24-hour urine collection. Multiple factors influence urine collection and the rate of protein and creatinine excretion. Urine collection is often incomplete, and therefore creatinine and protein excretion rates are underestimated. A random urine protein-creatinine (P-C) ratio has been shown over the years to be a reliable alternative to the 24-hour collection for detection and follow up of proteinuria. However, urine protein excretion may be influenced by physical activity. We studied 48 patients with proteinuria and varying levels of physical activity to determine the correlation between the measures of urine protein excretion. The correlation coefficient (r) between 24-hour urine total protein and random urine P-C ratio was 0.75 (P < 0.01) in the overall study population, but varied according to the level of proteinuria and physical activity in a stratified analysis: r = 0.99 (P < 0.001) and r = 0.95 (P < 0.01) in bedridden patients; r = 0.44 (P = not significant [NS]) and r = 0.54 (P = NS) in semiactive patients; and r = 0.44 (P = NS) and r = 0.58 (P < 0.05) in active patients with nephrotic- (>3500 mg/day) and non-nephrotic (<3500 mg/day) range proteinuria, respectively. The correlation appeared to be stronger between random urine and 24-hour urine P-C ratio for the overall study population (r = 0.84; P < 0.001), and when stratified according to the level of proteinuria and physical activity: r = 0.99 (P < 0.001) and r = 0.92 (P < 0.01) in bedridden patients; r = 0.61 (P = NS) and r = 0.54 (P = NS) in semiactive patients; and r = 0.64 (P < 0.02) and r = 0.52 (P < 0.05) in active patients with nephrotic and non-nephrotic range proteinuria, respectively. We conclude that the random urine P-C ratio is a reliable and practical way of estimating and following proteinuria, but its precision and accuracy may be affected by the level of patient physical activity.

Recent developments in HIV-related kidney disease

Although kidney disease has been a recognized complication of HIV infection since the beginning of the HIV epidemic, its epidemiology, underlying causes and treatment have evolved in developed countries where HAART has been widely available. HIV-associated nephropathy and HIV immune complex-mediated kidney disease were the prominent renal diagnoses in the earlier period of the HIV epidemic. While HIV immune complex-mediated kidney disease remains a common finding among HIV-infected individuals with kidney disease, the incidence of HIV-associated nephropathy has been diminishing in developed countries. The role of the metabolic effects of long-term HAART exposure and nephrotoxicity of certain antiretroviral medications on the development and progression of chronic kidney disease is now of increasing concern. The long-term clinical implications of acute kidney injury among HIV-infected persons are increasingly recognized. Kidney disease in HIV-infected persons continues to be a major risk factor for morbidity and mortality in this patient population; therefore, early recognition and treatment of kidney disease are imperative in lessening the impact of kidney disease on the health of HIV-infected individuals. This review focuses on recent developments and ongoing challenges in the understanding, diagnosis and management of HIV-related kidney disease.

[New trends in the laboratory diagnostics of proteinuria and albuminuria]

According to current clinical trials, albumin excretion is an early indicator of cardiovascular damage. While proteinuria is considered as a marker of kidney function, albuminuria indicates cardiovascular risk first of all. Sensitivity of the previous laboratory tests does not meet the clinical requirements, and the error of urine collection makes the results misleading. For that reason recent guidelines suggest to calculate albumin/creatinine (ACR) and protein/creatinine (PCR) measured from the first morning urine. For the clinical diagnosis of albuminuria the sensitive immunoturbidimetric assays are suggested. Albumin dipsticks are not recommended for the measurement of albuminuria. Wide-range urinary protein reagents are also available with high sensitivity, while serum reagents are not applicable (Biuret). The traceability of calibrator to a reference material is a critical requirement. Proteinuria and albuminuria of a patient should be monitored in the same laboratory, using a fixed method and cut-off value. Albumin/creatinine value should be reported together with gender-dependent reference range.

Outcome of pregnancy in patients with isolated proteinuria

PURPOSE OF REVIEW

The outcome of pregnancy in patients with isolated proteinuria is believed to be favorable. However, whether women with isolated proteinuria are at risk for progressing to preeclampsia has not been extensively studied.

RECENT FINDINGS

The amount of proteinuria is thought to increase in the early third trimester, irrespective of whether preeclampsia has been diagnosed. A dipstick urinalysis has a poor sensitivity (ranging from 22 to 86%) for the detection of significant proteinuria (> or = 0.3 g/day). Measurements of the levels of circulating angiogenic factors such as soluble fms-like tyrosine kinase 1, soluble endoglin, vascular endothelial growth factor, and placental growth factor suggest that gestational proteinuria is a mild variant of preeclampsia. In one study, women with isolated proteinuria (> or = 0.3 g/day) were found to be more likely to progress to preeclampsia than women with isolated hypertension. A considerable number of women with eclampsia exhibited proteinuria alone during their last antenatal visit performed within a week prior to their first convulsion.

SUMMARY

The outcome of women with a retrospective diagnosis of gestational proteinuria is generally favorable. However, a considerable number of women with isolated proteinuria develop hypertension and progress to preeclampsia. Therefore, the statement that the 'outcome of pregnancy in patients with isolated proteinuria is favorable' is misleading. Physicians should be aware of this type of preeclampsia when counseling patients. One possible explanation for the difficulty in diagnosing this form of preeclampsia might be the low sensitivity of the dipstick urinalysis technique for the detection of significant proteinuria.

Ex vivo application of carbon monoxide in UW solution prevents transplant-induced renal ischemia/reperfusion injury in pigs

I/R injury is a major deleterious factor of successful kidney transplantation (KTx). Carbon monoxide (CO) is an endogenous gaseous regulatory molecule, and exogenously delivered CO in low concentrations provides potent cytoprotection. This study evaluated efficacies of CO exposure to excised kidney grafts to inhibit I/R injury in the pig KTx model. Porcine kidneys were stored for 48 h in control UW or UW supplemented with CO (CO-UW) and autotransplanted in a 14-day follow-up study. In the control UW group, animal survival was 80% (4/5) with peak serum creatinine levels of 12.0 +/- 5.1 mg/dL. CO-UW showed potent protection, and peak creatinine levels were reduced to 6.9 +/- 1.4 mg/dL with 100% (5/5) survival without any noticeable adverse event or abnormal COHb value. Control grafts at 14 days showed significant tubular damages, focal fibrotic changes and numerous infiltrates. The CO-UW group showed significantly less severe histopathological changes with less TGF-beta and p-Smad3 expression. Grafts in CO-UW also showed significantly lower early mRNA levels for proinflammatory cytokines and less lipid peroxidation. CO in UW provides significant protection against renal I/R injury in the porcine KTx model. Ex vivo exposure of kidney grafts to CO during cold storage may therefore be a safe strategy to reduce I/R injury.

Assessing proteinuria in chronic kidney disease: protein-creatinine ratio versus albumin-creatinine ratio

BACKGROUND

Quantification of proteinuria is important in the assessment of chronic kidney disease (CKD). The aim of this study was to investigate the optimal test to identify significant proteinuria.

METHODS

We retrospectively assessed the relationship between total protein:creatinine ratio (TPCR), albumin:creatinine ratio (ACR) and 24-h urine total protein in 6842 patients with CKD focusing on performance at thresholds of 0.5 and 1 g/day of proteinuria.

RESULTS

The relationship between ACR and TPCR is non-linear. TPCR is highly correlated with 24-h urine protein (Spearman's rho = 0.91), though ACR also performs well (rho = 0.84). Using receiver-operator characteristic curve analysis, TPCR outperforms ACR at predicting 0.5 g/day [area under the curve (AUC) 0.967 vs 0.951, P < 0.001] and 1 g/day of proteinuria (AUC 0.968 vs 0.947, P = 0.004). A TPCR threshold of 100 mg/mmol had a higher sensitivity (94% vs 79%) but lower specificity (88% vs 95%) than an ACR of 70 mg/mmol to predict 1 g/day of total proteinuria. To achieve comparable sensitivity, the ACR threshold falls to 17.5 mg/mmol, with lower specificity than TPCR (69.8%). Sensitivity of TPCR rose with increasing age, and in females: to achieve 95% sensitivity in a man <49 years, requires a TPCR of 65 mg/mmol, compared to 179 mg/mmol in a woman >79 years. Non-albumin proteinuria was a lower proportion of total proteinuria in patients receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockade than in those who were not (P < 0.001).

CONCLUSIONS

TPCR is a more sensitive screening test than ACR to predict clinically relevant proteinuria. The diagnostic performance of both tests varies substantially with age and gender, and should be taken into consideration when interpreting results. Total proteinuria cannot be adequately predicted from ACR, and our results suggest that caution is appropriate before utilizing ACR in patients with non-diabetic CKD.

Should kidney tubular markers be adjusted for urine creatinine? The example of urinary cystatin C

BACKGROUND

Evaluation of specific urinary markers with respect to urine creatinine (uCreat) is common. However, as uCreat is a function of both glomerular filtration and tubular secretion, using uCreat for specific tubular markers, suggests that glomerular function is normal, and there is no tubular secretion. Thus, adjusting values of any tubular marker to uCreat, especially in patients with acute or even moderate chronic renal failure, can be misleading.

METHODS

Using urine cystatin-C (uCST3) as a model tubular marker for following 120 kidney graft recipients daily, we evaluated the utility of either uCST3 alone or the uCST3/uCreat ratio to detect tubular damage. All positive kidney biopsies were always associated with a uCST3>0.18 mg/L.

RESULTS

Using the uCST3/uCreat ratio, discrepancies regarding biopsy status were observed in nine patients (4 false positive, 5 false negative results). In two patients, variability of uCreat appeared to be the most important factor causing inconsistent uCST3/uCreat ratios. With a negative predictive value (NPV) of 85.7%, uCST3/uCreat can lead to errors in clinical interpretation. These errors can be avoided when estimates of tubular damage are based on uCST3 concentrations alone (NPV=100%).

CONCLUSIONS

We recommend using the uCST3 value to evaluate the extent of renal tubular damage. Indeed, our conflicting results on uCST3/uCreat can be extended to every marker of tubular function. Evaluating a urine marker specific for renal tubular damage to a second urine marker that is itself strongly dependent upon glomerular or other renal or non-renal conditions, impairs its clinical relevance and may lead to incorrect interpretations. Correction with uCreat can be performed only in pure glomerulopathy, when specific markers of glomerular function are measured (i.e., urinary albumin). In all other cases of renal diseases, such correction is inappropriate and should be avoided. Clin Chem Lab Med 2009;47:1553-6.

Avaliação do efeito da clorpromazina sobre a função renal de cães submetidos à isquemia e reperfusão

A isquemia renal está presente em diferentes situações como em cirurgias renais, vasculares e no transplante renal. O objetivo deste trabalho foi avaliar a integridade e a função renal de cães submetidos à isquemia e reperfusão com ou sem aplicação de clorpromazina. Para tanto foram utilizados 12 cães distribuídos aleatoriamente em dois grupos de seis indivíduos: grupo A com isquemia e reperfusão sem tratamento por clorpromazina e o grupo B com isquemia e reperfusão tratados previamente com clorpromazina. De cada cão foi coletado sangue e urina antes da isquemia, no inicio da reperfusão, após 120 minutos de reperfusão e semanalmente até 28º dia pós-cirúrgico para verificar possíveis efeitos tardios da isquemia/reperfusão. Avaliações da integridade e função renal foram feitas por exame físico, concentração sérica de ureia e creatinina e determinação da GGT urinária. A avaliação da relação proteína urinária/creatinina urinária (PU/CU) e atividade da GGT urinária são exames mais sensíveis para detectar lesão tubular aguda que o exame de urina de rotina, uma vez que estas variáveis apresentaram alteração mais precocemente. Não houve ação protetora da clorpromazina conforme constatado por meio da urinálise, dosagens séricas de ureia e creatinina, excreção urinária de GGT e PU/CU.