Measurement of albumin and low molecular weight proteins in the urine of newborn infants using a cotton wool ball collection method

Objective : The aim of this study was to investigate the inter-relationship between urinary excretion of alpha-1-microglobulin (AIM), retinol-binding protein (RBP) and albumin in term and premature neonates, with urine collected into cotton wool balls and extracted by a novel method. Subjects and methods : Sixty-four infants were studied on the first day of life; 26 had been born at term (37–42 weeks gestation) and 38 prematurely (24–28 weeks n = 16, 29–36 weeks n = 22). Urine collected into cotton wool balls was analysed following a new detergent extraction method, which resulted in a recovery rate of 94–107% for albumin, AIM, RBP and creatinine. Results : Urinary protein excretion, expressed as a ratio to urinary creatinine, decreased significantly with increasing gestational age (24–28 weeks, 29–36 weeks, 37–42 weeks: albuminxreatinine ratio mg/mmol mean 96.9, 31.7, 19.3; AIM: creatinine ratio mg/mmol mean 99.3, 37.0, 7.8; RBP: creatinine ratio mg/mmol mean 16.2, 3.8, and <0.01, below the limit of detection, respectively). When results were corrected for birthweight, this gestation-associated effect was still present for A1M and RBP, but not for albumin. In premature infants there was a significant positive correlation between AIM: creatinine ratio and RBP: creatinine ratio ( r = 0.85), and also between albumin and both AIM and RBP ( r = 0.82 and 0.77). Conclusion : Increased excretion of AIM, RBP and albumin at earlier gestational ages is probably due to proximal tubular immaturity, although tubular damage and also glomerular dysfunction cannot be excluded as possible explanations.     

痛风伴微量白蛋白尿患者胰岛素抵抗与红细胞膜胰岛素受体的关系

目的 探讨痛风伴微量白蛋白尿患者胰岛素抵抗与红细胞膜胰岛素受体的关系。方法 观察106例痛风患者，按是否合并微量白蛋白尿（MAU），将其分为MAU组和正常MAU组（NMAU），测定空腹、餐后2h血糖、胰岛素及空腹血脂、血尿酸（UA），并检测高、低亲和力红细胞膜胰岛素受体数目（R1、R2）和高、低亲和力常数（K1、K2），分析痛风伴MAU患者胰岛素抵抗与红细胞膜胰岛素受体的关系。结果 MAU组空腹胰岛素（FINS）、甘油三酯（TG）、低密度脂蛋白（LDL-c）及胰岛素抵抗指数（HOMA—IR），分别为：（16±4）mU／L、（2．5±0．6）mmol／L、（3．2±0．5）mmol／L和3．6±1．2，正常MAU组分别为（13±3）mU／L、（2．3±0．8）mmol／L、（3．0±0．5）mmol／L及3．0±0．4，上述指标两组间比较差异有统计学意义（P〈0．05）。痛风患者合并MAU红细胞膜胰岛素受体数目（R1）较正常MAU组明显减少，两组间比较差异有统计学意义（P〈0．05）。痛风患者合并MAU的Pearson相关分析结果示：HOMA—IR与年龄、体重指数（BMI）、TG、LDL—c、UA、UAER呈正相关（P〈0．05或P〈0．01），与R1、R2、K1、K2呈负相关（P〈0．05或P〈0．01）。多元线性逐步回归分析提示BMI、年龄、R1是影响痛风合并MAU患者胰岛素抵抗的独立危险因素。结论 痛风合并MAU时存在胰岛素抵抗，且与红细胞膜胰岛素受体数目减少密切相关。     

Glomerular filtration rate, albuminuria and risk of cardiovascular and all-cause mortality in type 2 diabetic individuals

Background and aims

To assess all-cause and cardiovascular mortality in type 2 diabetic individuals according to estimated glomerular filtration rate (eGFR) and albuminuria.

Methods and results

We followed 2823 type 2 diabetic outpatients for a median period of 6 years for the occurrence of all-cause and cardiovascular mortality. eGFR was estimated using the abbreviated Modification of Diet in Renal Disease study equation. At baseline, an eGFR <60 ml/min/1.73 m² and abnormal albuminuria were present in 22.5% and 26.0% of participants, respectively. During follow-up, a total of 309 patients died, 53% of deaths were secondary to cardiovascular causes. Risks of all-cause and cardiovascular mortality increased progressively with decreasing eGFR and increasing albuminuria. After adjustment for age, sex, body mass index, smoking, hypertension, diabetes duration, hemoglobin A1c, plasma lipids, medications use (hypoglycemic, anti-hypertensive, anti-platelet or lipid-lowering drugs) and albuminuria, the hazard ratios of all-cause and cardiovascular mortality per 1-SD decrease in eGFR were 1.53 (95%CI 1.2-2.0; p < 0.0001) and 1.51 (95%CI 1.05-2.2; p = 0.023), respectively. A similar pattern in the risk of all-cause and cardiovascular mortality was seen for albuminuria (1.14, 1.01-1.3, p = 0.028 and 1.19, 1.01-1.4, p = 0.043 per 1-SD increase in albuminuria, respectively) after adjustment for eGFR and other potential confounders.

Conclusions

These findings suggest that both decreasing eGFR and rising albuminuria are associated with all-cause and cardiovascular mortality in type 2 diabetic individuals, independently of traditional risk factors and diabetes-related variables.     

GAS6 intron 8 c.834 + 7G > A gene polymorphism in diabetic nephropathy

Abstract

Background - Aim: In animal experiments, growth arrest-specific 6 (Gas6) protein plays a key role in the development of mesangial cell and glomerular hypertrophy in the early phase of diabetic nephropathy, and diabetic nephropathy is prevented by warfarin-induced inhibition of GAS6 protein. It was shown that GAS6 intron 8 c.834?+?7G?>?A polymorphism is protective against type 2 diabetes mellitus, and AA genotype is associated with higher blood levels of GAS6 protein. Our aim is to investigate whether this polymorphism is a risk factor for diabetic nephropathy in type 2 diabetes mellitus. Method: Eighty-seven patients with diabetic nephropathy were compared with 66 non-diabetic controls in terms of GAS6 intron 8 c.834?+?7G?>?A polymorphism. Patients with history of stroke, ischemic heart disease were excluded. Each patient was examined by the ophthalmologist to determine diabetic retinopathy. Results: Frequency of GG, GA and AA genotypes are similar in diabetic nephropathy and control groups according to GAS6 intron 8 c.834?+?7G?>?A polymorphism (p?=?0.837). Rate of diabetic retinopathy was 54.02%. In the subgroup analysis, GA genotype was significantly more frequent than GG genotype in patients with diabetic retinopathy when compared to without diabetic retinopathy (p?=?0.010). Conclusion: In our study, GAS6 intron 8 c.834?+?7G?>?A polymorphism was not associated with diabetic nephropathy in type 2 diabetes mellitus. However, heterozygous state of this polymorphism may be a risk factor for diabetic retinopathy in patients with diabetic nephropathy.     

Assessment of cardiovascular risk and social framework of Cape Verdean university students studying in Portugal

Introduction

The migration of African populations to Europe poses problems of adaptation that may increase the risk of cardiovascular disease. We assessed the cardiovascular risk of Cape Verdean university students studying in Portugal (CV-PT) compared to Cape Verdean university students in Cape Verde (CV-CV) and to Caucasian university students in Portugal (PT-PT).

The Effect of Calcium Channel Blockers on Moderate or Severe Albuminuria in Diabetic,Hypertensive Patients

ObjectivesInhibitors of the renin-angiotensin system are recommended for the management of albuminuria in patients with hypertension and diabetes mellitus, but there is little consensus about alternative therapies. Calcium channel blockers are recommended for the management of hypertension, but the data are controversial regarding their role in patients with albuminuria. This review was designed to assess the efficacy of calcium channel blockers compared with inhibitors of the renin-angiotensin system in decreasing albuminuria in diabetic, hypertensive patients with nephropathy.MethodsWe searched MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov for records that compared calcium channel blockers to inhibitors of the renin-angiotensin system and reported pre- and postintervention albuminuria measurements. Two reviewers independently screened abstracts for randomized, controlled trials in adults. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to select 29 trials from 855 records. We synthesized the data through a random-effects model.ResultsWe analyzed data from 2113 trial participants with hypertension and diabetes mellitus who had the equivalent of ≥30 mg/day of urinary albumin excretion. Inhibitors of the renin-angiotensin system were more effective than calcium channel blockers in decreasing albuminuria (standardized difference in means ?0.442; confidence interval, ?0.660 to ?0.225; P < .001). This finding was independent of the blood pressure response to treatment. There was no difference between the 2 drug classes regarding markers of renal function.ConclusionsInhibitors of the renin-angiotensin system are superior to calcium channel blockers for the reduction of albuminuria in nephropathy due to hypertension and diabetes mellitus. The net clinical benefit, however, is small.     

Obesity as a predictive factor for chronic kidney disease in adults: systematic review and meta-analysis

Chronic kidney disease (CKD) is one of the main chronic diseases affecting the world population due to its high prevalence and increasing morbidity. Similarly, obesity gained the interest of the scientific community as it directly or indirectly increases mortality from cardiovascular causes, and its prevalence characterizes a pandemic. The objective of this study was to investigate obesity measured by body mass index as a predictor for end-stage renal disease in the general adult population. A systematic review and meta-analysis was carried out by searching 10 databases for prospective or retrospective cohort studies, with no restrictions on the language of publication, including adults with obesity without previous renal disease and who evolved to CKD (diagnosed by estimated glomerular filtration rate below 60 mL&mac_middot;min^-1&mac_middot;(1.73 m²)^-1 over the follow-up period. The R software and Meta package were used for data analysis. After removing duplicates, 5431 studies were submitted to the steps of the systematic review, and 21 articles were included in the data analysis. In total, 3,504,303 patients, 521,216 with obesity, and an average follow-up time of 9.86 years were included. The relative risk of obese people for developing CKD in the random effects model was 1.81 (95%CI: 1.52-2.16). The evidence found in this meta-analysis confirmed that obese people are at higher risk of developing CKD that the non-obese population (1.81 times higher), with obesity being a priority risk factor in preventive actions.     

Reduction of heparan sulphate-associated anionic sites in the glomerular basement membrane of rats with streptozotocin-induced diabetic nephropathy

Summary Heparan sulphate-associated anionic sites in the glomerular basement membrane were studied in rats 8 months after induction of diabetes by streptozotocin and in age- and sex-matched control rats, employing the cationic dye cuprolinic blue. Morphometric analysis at the ultrastructural level was performed using a computerized image processor. The heparan sulphate specificity of the cuprolinic blue staining was demonstrated by glycosaminoglycan-degrading enzymes, showing that pretreatment of the sections with heparitinase abolished all staining, whereas chondroitinase ABC had no effect. The majority of anionic sites (74% in diabetic and 81% in control rats) were found within the lamina rara externa of the glomerular basement membrane. A minority of anionic sites were scattered throughout the lamina densa and lamina rara interna, and were significantly smaller than those in the lamina rara externa of the glomerular basement membrane (p<0.001 and p<0.01 for diabetic and control rats, respectively). Diabetic rats progressively developed albuminuria reaching 40.3 (32.2–62.0) mg/24 h after 8 months in contrast to the control animals (0.8 (0.2–0.9) mg/24 h, p<0.002). At the same time, the number of heparan sulphate anionic sites and the total anionic site surface (number of anionic sites × mean anionic site surface) in the lamina rara externa of the glomerular basement membrane was reduced by 19% (p<0.021) and by 26% (p<0.02), respectively. Number and total anionic site surface in the remaining part of the glomerular basement membrane (lamina densa and lamina rara interna) were not significantly changed. We conclude that in streptozotocin-diabetic rats with an increased urinary albumin excretion, a reduced heparan sulphate charge barrier/density is found at the lamina rara externa of the glomerular basement membrane.Abbreviations HS Heparan sulphate - GBM glomerular basement membrane - HSPG heparan sulphate proteoglycan - STZ streptozotocin - LRE lamina rara externa - LD lamina densa - LD + LRI lamina densa + lamina rara interna - ANOVA analysis of variance     

Amiloride lowers blood pressure and attenuates urine plasminogen activation in patients with treatment–resistant hypertension

In conditions with albuminuria, plasminogen is aberrantly filtered across the glomerular barrier and activated along the tubular system to plasmin. In the collecting duct, plasmin activates epithelial sodium channels (ENaC) proteolytically. Hyperactivity of ENaC could link microalbuminuria/proteinuria to resistant hypertension. Amiloride, an ENaC inhibitor, inhibits urokinase–type plasminogen activator. We hypothesized that amiloride (1) reduces blood pressure (BP); (2) attenuates plasminogen–to–plasmin activation; and (3) inhibits urine urokinase–type plasminogen activator in patients with resistant hypertension and type 2 diabetes mellitus (T2DM).In an open–label, non–randomized, 8–week intervention study, a cohort (n = 80) of patients with resistant hypertension and T2DM were included. Amiloride (5 mg/d) was added to previous triple antihypertensive treatment (including a diuretic and an inhibitor of the renin–angiotensin–aldosterone system) and increased to 10 mg if BP control was not achieved at 4 weeks. Complete dataset for urine analysis was available in 60 patients. Systolic and diastolic BP measured by ambulatory BP monitoring and office monitoring were significantly reduced. Average daytime BP was reduced by 6.3/3.0 mm Hg. Seven of 80 cases (9%) discontinued amiloride due to hyperkalemia >5.5 mol/L, the most frequent adverse event. Urinary plasmin(ogen) and albumin excretions were significantly reduced after amiloride treatment (P < .0001). Urokinase activity was detectable in macroalbuminuric urine, with a tendency toward reduction in activity after amiloride treatment. Amiloride lowers BP, urine plasminogen excretion and activation, and albumin/creatinine ratio, and is a relevant add–on medication for the treatment of resistant hypertension in patients with T2DM and microalbuminuria.     

Cystatin C is better than albuminuria as a predictor of pulse wave velocity in hypertensive patients

Introduction: Arterial stiffness is important in the evaluation of the cardiovascular risk in both general population and hypertensive patients. In this study, we aimed to investigate the associations of both serum cystatin C levels and albuminuria with arterial stiffness in healthy controls and hypertensive patients.

Patients and methods: Seventy-six healthy controls (male/female?=?44/32) and 76 hypertensive patients (male/female?=?43/33) were enrolled. Arterial stiffness parameters such as augmentation index (AIx) and pulse wave velocity (PWV) were non-invasively measured with the Arteriograph (Tensiomed Ltd., Budapest, Hungary).

Results: AIx (31.92?±?14.31 vs. 27.95?±?11.03, p?=?0.03) and PWV (9.84?±?1.62 vs. 8.87?±?2.04, p?p?=?0.002) and higher serum cystatin C levels [0.76 (0.67–0.95) vs. 0.68 (0.62–0.78) mg/L, p?=?0.03]. In the hypertensive group, AIx was significantly correlated with PWV (r?=?0.519, p?r?=?–0.438, p?=?0.003), mean arterial pressure (MAP) (r?=?0.288, p?=?0.015) and urinary albumin–creatinine ratio (ACR) (r?=?0.386, p?=?0.004). PWV was associated with serum cystatin C (r?=?0.442, p?=?0.003) and MAP (r?=?0.377, p?=?0.001). In the linear regression analysis (model r?=?0.577, p?=?0.006) for the prediction of PWV in hypertensive patients, MAP, urinary ACR, age and serum cystatin C levels were included as independent variables. Cystatin C was found to be the significant determinant of PWV in hypertensive patients.

Conclusion: Multivariate analysis revealed that serum cystatin C but not albuminuria was significantly associated with PWV in hypertensive patients. Serum cystatin C may be better than albuminuria as a predictor of arterial stiffness in hypertensive patients.