Microalbuminuria and hypertension with focus on type 1 and type 2 diabetes

[Prognostic Value of Isolated High Serum Cystatin C Levels Without Glomerular Filtration Rate Reduction]

OBJECTIVES

Cystatin C is increasingly used as a marker of renal function as a complement to serum creatinine and glomerular filtration rate (GFR). We have assessed its efficacy as a predictor of mortality in a group of patients with increased cystatin C but GFR> 60mL/min.

DESIGN AND METHODS

We included 608 patients, 65.9% male, 34.6% had diabetes mellitus. The mean age was 58.5±14.5 years and a mean GFR of 64.1±33.5mL/min. Patients were divided into 3 groups: CONTROL (normal cystatin C and GFR> 60mL/min, age 53.3±12.8years, GFR 96.6±22.4mL/min,n=193), INCREASED CYSTATIN (cystatin C>1.03mg/l and GFR>60mL/min, age 58.9±13,1years, GFR 72.2±10.4mL/min, n=40) and CKD (chronic kidney disease, increased cystatin C and GFR <60mL/min, age 61.4±14.8years, GFR 36.0±12.7mL/min, n=160). The relationship with overall mortality was analyzed using the Kaplan-Meier method.

RESULTS

Mean cystatin C was 0.75±0.13 versus 1.79±0.54 in CKD group and 1.14±0.14mg/l, p <0.001). In CONTROL group survival was 93.9% at 5y, compared to 78.8% in the ERC group and 82.3% in the INCREASED CYSTATIN group (p <0.001) Five-year survival before renal replacement therapy was also different for the ERC group (73%, p <0.001 Log Rank) but not between the other two groups (CONTROL 99.0%, INCREASED CYSTATIN 94.3% p=0.08).

CONCLUSIONS

Increased plasmatic levels of cystatin C in patients with GFR> 60mL/min was a predictor of increased mortality but not of progression to end-stage renal failure. These results confirm the interest of routinely measuring cystatin C.

Enhanced Kidney Damage Induced by Increasing Nonylphenol Doses: Impact on Autophagy-Related Proteins and Proinflammatory Cytokines in Rats

Nonylphenol (NP) is an organic pollutant and endocrine disruptor chemical that has harmful effects on the environment and living organisms. This study looked at whether kidney tissues subjected to increasing doses of nonylphenol generated alterations in histopathologic, pro-inflammatory, and autophagic markers. Fifty rats were divided into five groups of ten each: group I: healthy group, II: control (corn oil), group III: 25 μl/kg NP, group IV: 50 μl/kg NP, group V: 75 μl/kg NP. The kidney tissue samples were obtained for histopathological, immunohistochemical, and biochemical analyses. The histological deteriorations observed in all NP groups included tubular epithelial cell degeneration, inflammation areas, and hemorrhage. The immunohistochemical investigations showed that NP significantly elevated the autophagy markers (Beclin-1, LC3/2, p62), pro-inflammatory cytokines (TNF-α, IL-6), HIF-1α, and eNOS in group III, IV and V compared with group I and II. The biochemical analysis also revealed that pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) increased in correlation with the NP doses, but only IL-1β reached statistical significance in NP treated rats kidney tissue. The biochemical findings have been confirmed by the histological studies. The damage to renal tissue caused by NP exposure may worsen it by increasing inflammatory and autophagic markers.

Diabetic Nephropathy and Gaseous Modulators

Diabetic nephropathy (DN) remains the leading cause of vascular morbidity and mortality in diabetes patients. Despite the progress in understanding the diabetic disease process and advanced management of nephropathy, a number of patients still progress to end-stage renal disease (ESRD). The underlying mechanism still needs to be clarified. Gaseous signaling molecules, so-called gasotransmitters, such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S), have been shown to play an essential role in the development, progression, and ramification of DN depending on their availability and physiological actions. Although the studies on gasotransmitter regulations of DN are still emerging, the evidence revealed an aberrant level of gasotransmitters in patients with diabetes. In studies, different gasotransmitter donors have been implicated in ameliorating diabetic renal dysfunction. In this perspective, we summarized an overview of the recent advances in the physiological relevance of the gaseous molecules and their multifaceted interaction with other potential factors, such as extracellular matrix (ECM), in the severity modulation of DN. Moreover, the perspective of the present review highlights the possible therapeutic interventions of gasotransmitters in ameliorating this dreaded disease.

The many faces of hypertension in individuals with type 1 diabetes

Several disturbed blood pressure (BP) patterns, including disparities between office and out-of-office BP measurements (such as white-coat and masked hypertension), disturbed circadian BP variability (such as abnormal dipping patterns and nocturnal hypertension) and treatment-resistant hypertension, are common in individuals with type 1 diabetes. Consequently, office or home BP measurements alone may not reflect real BP variation and may lead to inadequate diagnosis and treatment of hypertension. The early detection of these disturbed BP patterns is especially crucial in individuals with type 1 diabetes, as these patterns may indicate future development of adverse cardiovascular and renal outcomes. In this review we will describe these disturbed BP patterns and discuss recent findings on their prevalence and outcomes. We will also address critical areas for future research to determine the true prevalence and prognosis of disturbed BP patterns, and to optimize and improve the knowledge and management of high-risk individuals with type 1 diabetes and disturbed BP patterns.

Identification and validation of key biomarkers for the early diagnosis of diabetic kidney disease

Background: Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. This study explored the core genes and pathways associated with DKD to identify potential diagnostic and therapeutic targets.

Methods: We downloaded microarray datasets GSE96804 and GSE104948 from the Gene Expression Omnibus (GEO) database. The dataset includes a total of 53 DKD samples and 41 normal samples. Differentially expressed genes (DEGs) were identified using the R package “limma”. The Metascape database was subjected to Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses to identify the pathway and functional annotations of DEGs. A WGCAN network was constructed, the hub genes in the turquoise module were screened, and the core genes were selected using LASSO regression to construct a diagnostic model that was then validated in an independent dataset. The core genes were verified by in vitro and in vivo experiments.

Results: A total of 430 DEGs were identified in the GSE96804 dataset, including 285 upregulated and 145 downregulated DEGs. WGCNA screened out 128 modeled candidate gene sets. A total of eight genes characteristic of DKD were identified by LASSO regression to build a prediction model. The results showed accuracies of 99.15% in the training set (GSE96804) and 94.44% and 100%, respectively, in the test (GSE104948-GPL22945 and GSE104948-GPL24120). Three core genes (OAS1, SECTM1, and SNW1) with high connectivity were selected among the modeled genes. In vitro and in vivo experiments confirmed the upregulation of these genes.

Conclusion: Bioinformatics analysis combined with experimental validation identified three novel DKD-specific genes. These findings may advance our understanding of the molecular basis of DKD and provide potential therapeutic targets for its clinical management.

The possible antioxidant capabilities of formononetin in guarding against streptozotocin-induced diabetic nephropathy in rats

Background

Oxidative stress has been considered as a contributory aspect for major complications of diabetes mellitus consisting of diabetic nephropathy. This study aimed to examine the therapeutic effect of formononetin in streptozotocin (STZ)-induced diabetic nephropathy through measuring biochemical parameters, oxidative indicators, and histopathological examination of renal tissues.

Results

Administration of a dose of STZ (55 mg/kg of body weight) intraperitoneal induced diabetic nephropathy in rats as indicated by an increase in serum glucose, creatinine, triglyceride, cholesterol, and BUN levels related to the depletion of serum albumin level. Besides, STZ treatment led to the depletion of antioxidant enzymes together with superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT). Administration of formononetin at the dose of 10, 20, and 40 mg/kg extensively decreased biochemical parameters with a rise in serum albumin level. Formononetin was observed to improved antioxidant enzyme ranges and offered protection against lipid peroxidation (LPO). STZ administered rats show an elevated level of TNF-α and IL-6. Meanwhile, formononetin-treated rats inhibited the elevated level of cytokine.

Conclusion

This study concluded that formononetin may additionally modulate oxidative stress and protected renal tissues from STZ injury. It also showed improvement in renal histopathological architecture in STZ-induced diabetic nephropathy.

Endothelial glycocalyx restoration by growth factors in diabetic nephropathy

The endothelial glycocalyx (eGlx) constitutes the first barrier to protein in all blood vessels. This is particularly noteworthy in the renal glomerulus, an ultrafiltration barrier. Leakage of protein, such as albumin, across glomerular capillaries results in albumin in the urine (albuminuria). This is a hall mark of kidney disease and can reflect loss of blood vessel integrity in microvascular beds elsewhere. We discuss evidence demonstrating that targeted damage to the glomerular eGlx results in increased glomerular albumin permeability. EGlx is lost in diabetes and experimental models demonstrate loss from glomerular endothelial cells. Vascular endothelial growth factor (VEGF)A is upregulated in early diabetes, which is associated with albuminuria. Treatment with paracrine growth factors such as VEGFC, VEGF165b and angiopoietin-1 can modify VEGFA signalling, rescue albumin permeability and restore glomerular eGlx in models of diabetes. Manipulation of VEGF receptor 2 signalling, or a common eGlx biosynthesis pathway by these growth factors, may protect and restore the eGlx layer. This would help to direct future therapeutics in diabetic nephropathy.

Sensitive detection of albuminuria by graphene oxide-mediated fluorescence quenching aptasensor

Albuminuria is a pathological condition wherein the human serum albumin (HSA) protein is present in abnormally excess amounts in the urine. A simple and sensitive graphene oxide-mediated fluorescence quenching aptasensor is developed to quantify albumin in urine samples and HSA in serum samples. The aptamer-bound HSA used in this aptasensor has hairpin structures, which are characteristic of the aptamer binding site. The limit of detection of the developed platform is 0.05 μg·mL^-1 and the detection range is 0.1-14.0 μg·mL^-1, which covers the albuminuria concentration range present in normal human urine and the urine of the patient with kidney diseases. This approach can be modified to measure HSA using a high-throughput quantification platform and portable point of care testing. In addition, the production cost for one reaction is cheaper than those for other standard automated methods. Therefore, this aptasensor has significant potential for commercialization and wide-scale public use.

Long-term case study of a Wuzhishan miniature pig with diabetes

BACKGROUND

Miniature pigs are attractive animal models for exploring diabetes because they are similar to humans in terms of physiological structure and metabolism. However, little is known about the complications of diabetes in pigs.

METHODS

In this study, a 28-month observation of a Wuzhishan miniature pig with streptozotocin (STZ)-induced (120 mg/kg) diabetes was conducted, to investigate diabetes-related complications and the possibility of self-recovery in miniature pigs. Blood glucose, serum and urinary biochemistry was measured, and histopathologic examinations of eyes, kidney and pancreas were made.

RESULTS

During the observation, diabetic complications of eyes and kidney were observed. The eye complications included bilateral cataracts in the 15th month and degeneration of inner retina and microaneurysm in the 28th month. Kidney complications included glomerular mesangial expansion, focal segmental glomerular sclerosis, and renal tubular epithelial degeneration, but no proteinuria was observed. By 28 months after the application of STZ, with no treatment given, blood glucose had recovered and the number of pancreatic islet beta-cells had increased significantly.

CONCLUSIONS

We showed that the STZ-induced diabetes model in miniature pigs could accurately mimic the pathological changes of human diabetes, and that pancreatic islet beta-cell regeneration did occur in an adult miniature pig, providing a new means for exploring diabetic complications and pancreatic islet beta-cell regeneration.

Immune-unreactive urinary albumin as a predictor of cardiovascular events: the Hortega Study

BACKGROUND

We aimed to determine if immune-unreactive albumin excretion (IURAE) is associated with cardiovascular (CV) events in a representative sample of a general population from Spain.

METHODS

We included 1297 subjects (mean age ± standard error 48.0 ± 0.2 years, 48% females), who participated in the Hortega Follow-Up Study. The primary endpoint was incidence of fatal and non-fatal CV events. Urinary albumin excretion (UAE) was measured in spot voided urine, frozen at -80°C, by immunonephelometry [immune-reactive albumin excretion (IRAE)] and by high-performance liquid chromatography (HPLC) [total albumin excretion (AE)]. IURAE was calculated as the difference between HPLC measurements and IRAE. We estimated fully adjusted hazard ratios (HRs) of CV incidence by Cox regression for IRAE, IURAE and total AE.

RESULTS

After an average at-risk follow-up of 13 years, we observed 172 CV events. urinary albumin to creatinine ratio (UACR) of ≥30 mg/g assessed by IRAE, IURAE or total AE concentrations was observed in 74, 273 and 417 participants, respectively. Among discordant pairs, there were 49 events in those classified as micro- and macroalbuminuric by IURAE, but normoalbuminuric by IRAE. Only the IRAE was a significant independent factor for the incidence of CV events [HR (95% confidence interval) 1.15 (1.04-1.27)]. The association of UAE with CV events was mainly driven by heart failure (HF) [HR 1.33 (1.15-1.55) for IRAE; HR 1.38 (1.06-1.79) for IURAE; HR 1.62 (1.22-2.13) for total AE]. Those subjects who were micro- and macroalbuminuric by both IRAE and IURAE had a significant increase in risk for any CV event, and especially for HF.

CONCLUSIONS

IRAE, IURAE and AE were associated with an increased risk for CV events, but IRAE offered better prognostic assessment.

Luteolin attenuates high glucose-induced podocyte injury via suppressing NLRP3 inflammasome pathway

AIMS

Diabetic nephropathy is a growing health concern, which is reported to be associated with inflammation. Luteolin has been explored for the treatment of some diabetic complications. Although several studies have verified the effect of luteolin on diabetic nephropathy, the mechanism by which the therapeutic effects of luteolin on diabetic nephropathy has not been established. Therefore, we aimed to investigate the effect of luteolin on diabetic nephropathy and its underlying mechanism.

MAIN METHODS

We used western blot, Real-time PCR, immunofluorescence and flow cytometry to analyze the effects of luteolin on podocyte injury and NOD-like receptor family and pyrin domain-containing protein 3 (NLRP3) inflammasome activation in high glucose (HG) condition. Reactive oxygen species (ROS) generation was measured by flow cytometry and malondialdehyde (MDA) level. To investigate the potential mechanism, we examined cell apoptosis upon transfection of siNLRP3.

KEY FINDINGS

We showed that luteolin treatment could protect podocyte against HG-induced cell apoptotic and mitochondrial membrane potential collapse. In addition, luteolin significantly reduced NLRP3 inflammasome formation and subsequent interleukin-1β (IL-1β) secretion in HG-induced MPC-5 cells. Interestingly, siNLRP3 abolished the effect of luteolin on cell apoptosis, suggesting that the anti-apoptotic effect was found to be mostly related to NLRP3 inflammasome.

SIGNIFICANCE

In summary, our data demonstrated the abilities of luteolin to inhibit podocyte injury and NLRP3 inflammasome activation, which could be used in the treatment of diabetic nephropathy.

Variation of Urine Parameters among Diabetic Patients: A Cross-Sectional Study

Background

Diabetic kidney disease is a common and severe microvascular complication of diabetes mellitus (DM). There are limited data regarding alteration of urine parameters other than proteinuria among DM patients.

Methods

Institution based cross-sectional study was conducted from February to May 2017 to assess alteration of urine parameters among DM patients at the University of Gondar Hospital, Northwest Ethiopia. A Systematic random sampling technique was used to recruit adult (≥18 years) diabetic participants. Data were collected after ethical requirements had been fulfilled. The degree of association between variables was evaluated through bivariable and multivariable logistic regression models.

Results

The majority (69.4%) of the study participants were type 2 DM patients. The prevalence of altered urine chemical parameters was 11.3% proteinuria, 4.5% ketonuria, 13.6% hematuria, 53.8% glucosuria, 24.9% leukocyturia and 1.7% positive for nitrite. Diastolic blood pressure and poor glycemic control were significantly associated with proteinuria. Male participants were 2.4 times more likely to have leukocyturia than female participants. The prevalence of abnormally increased microscopic findings was red blood cells 3.1%, white blood cells 12.5%, epithelial cells 27.5%, yeast cells 1.7%, bacteria 17.8%, casts 3.7% and crystals 29.2%.

Conclusions

The prevalence of altered urine parameters among DM patients is found to be considerable. These increased prevalences of altered urine parameters are potential indicators for diabetic kidney disease.

Prevalence and Factors Associated with Microalbuminuria among Type 2 Diabetic Patients : A Hospital Based Study

INTRODUCTION

Microalbuminuria is the earliest clinical evidence of diabetic nephropathy. However, prevalence and associated factors with microalbuminuria among type 2 diabetic patients has been understudied area of research in Nepalese context. This study aimed to determine the prevalence and factors associated with microalbuminuria among type 2 diabetic patients.

METHODS

This study was a hospital-based cross-sectional study. Blood samples for serum creatinine, Hemoglobin A1C, Fasting blood sugar and urine sample for microalbumin and urine creatinine were collected and analyzed using validated and standardized tools from a total of 400 Type 2 diabetic patients in Devdaha Medical College and Teaching Hospital, Rupandehi, Nepal from August 2014 to September 2017. Microalbuminuria was defined as urinary albumin-to-creatinine ratio greater than 30 and less than300 μg /mg of creatinine Results: Of 400 type 2 diabetic patients, 186 (46.5%) had microalbuminuria. The mean values of FBS, HbA1C, serum creatinine, microalbumin, microalbumin/urine creatinine ratio were higher in microalbuminuria group. Microalbuminuria was significantly positively correlated with duration of diabetes, FBS, HbA1C, serum creatinine, microalbumin, microalbumin/ urine creatinine, systolic blood pressure and diastolic blood pressure (P< 0.01).

CONCLUSIONS

Our study demonstrated that nearly half of the type 2 diabetic patients had microalbuminuria. Our results emphasize to increase to accessibility to microalbuminuria testing for all the type 2 diabetic patients and bring them under medical supervision to reduce the unwanted complications of diabetes mellitus.

Long-term intra-individual variability of albuminuria in type 2 diabetes mellitus: implications for categorization of albumin excretion rate

BACKGROUND

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease in the Western world. Early and accurate identification of DKD offers the best chance of slowing the progression of kidney disease. An important method for evaluating risk of progressive DKD is abnormal albumin excretion rate (AER). Due to the high variability in AER, most guidelines recommend the use of more than or equal to two out of three AER measurements within a 3- to 6-month period to categorise AER. There are recognised limitations of using AER as a marker of DKD because one quarter of patients with type 2 diabetes may develop kidney disease without an increase in albuminuria and spontaneous regression of albuminuria occurs frequently. Nevertheless, it is important to investigate the long-term intra-individual variability of AER in participants with type 2 diabetes.

METHODS

Consecutive AER measurements (median 19 per subject) were performed in 497 participants with type 2 diabetes from 1999 to 2012 (mean follow-up 7.9 ± 3 years). Baseline clinical characteristics were collected to determine associations with AER variability. Participants were categorised as having normo-, micro- or macroalbuminuria according to their initial three AER measurements. Participants were then categorised into four patterns of AER trajectories: persistent, intermittent, progressing and regressing. Coefficients of variation were used to measure intra-individual AER variability.

RESULTS

The median coefficient of variation of AER was 53.3%, 76.0% and 67.0% for subjects with normo-, micro- or macroalbuminuria at baseline. The coefficient of variation of AER was 37.7%, 66% and 94.8% for subjects with persistent, intermittent and progressing normoalbuminuria; 43%, 70.6%, 86.1% and 82.3% for subjects with persistent, intermittent, progressing and regressing microalbuminuria; and 55.2%, 67% and 82.4% for subjects with persistent, intermittent and regressing macroalbuminuria, respectively.

CONCLUSION

High long-term variability of AER suggests that two out of three AER measurements may not always be adequate for the optimal categorisation and prediction of AER.

Prevalence and associations of microalbuminuria in proteinuria-negative patients with type 2 diabetes in two regional hospitals in Cameroon: a cross-sectional study

Background

Microalbuminuria (MA) is the earliest clinical evidence of diabetic nephropathy, but most patients in sub-Saharan Africa (SSA) only have access to much cheaper dipstick proteinuria as a means to screen for diabetic nephropathy. The aim of this study was to determine the prevalence and associations of MA among proteinuria-negative type 2 diabetic patients in a SSA setting.

Methods

In this cross-sectional study, patients with type 2 diabetes screened negative for dipstick proteinuria in a primary healthcare hospital were assessed. Detection of microalbuminuria was carried out in two steps: qualitative detection using special microalbumin urine strip, and quantitative laboratory measurement and calculation of urinary albumin-to-creatinine ratio (UACR). Microalbuminuria was defined as UACR of 30–300 mg/g.

Results

A total of 162 type 2 diabetic patients were included. Using quantitative assessment, the prevalence of microalbuminuria was 14.2% (95% CI 8.8–19.6) whereas 26.5% (95% CI 19.8–34.0) had microalbuminuria with urine strip. The mean systolic blood pressure (p = 0.032), diastolic blood pressure (p = 0.032) and serum creatinine concentration (p < 0.001) were higher in people with microalbuminuria as compared to those with normoalbuminuria, whereas the mean body mass index (p = 0.046) and mean eGFR (p < 0.001) were lower in the albuminuria group. In multiple linear regression, eGFR (p = 0.001) and serum creatinine concentration (p = 0.003) were independently associated with increased UACR.

Conclusions

One in every seven proteinuria-negative type 2 diabetic patients has microalbuminuria in primary care setting in Cameroon; microalbuminuria is associated with higher systolic and diastolic blood pressure, and declining kidney function. Our results emphasize the urgent need to increase the accessibility to microalbuminuria testing to ensure that all diabetic patients with negative dipstick proteinuria can benefit.

The prevalence of hypertension in relation with the normal albuminuria range in type 2 diabetes mellitus within the South Korean population: The Korean National Health and Nutrition Examination Survey, 2011-2012

AIMS

The coexistence of hypertension (HTN) and diabetes mellitus (DM) increases the risk of cardiovascular disease. In some studies, normal albuminuria has also been associated with cardiovascular disease and HTN. Therefore, we examined the relationships between albuminuria and the prevalence of HTN and its control rate in type 2 DM patients.

RESULTS

We analyzed data from the 2011-2012 Korea National Health and Nutrition Examination Survey, and 1188 subjects with type 2 DM were included in the study. We divided albuminuria into 3 albuminuria tertiles (T): T1: <4.82mg/g; T2: 4.82-17.56mg/g; and T3: ≥17.56mg/g. The systolic and diastolic blood pressure were positively correlated with the albumin to creatinine ratio (ACR) after adjusting for all covariates (P<0.001). Type 2 DM subjects with hypertension had more ACR T3 (odds ratio=2.018, 95% confidence interval=1.445-2.818) than subjects without HTN. Subjects with controlled HTN had less ACR T3 than subjects without controlled HTN (odds ratio=0.566, 95% confidence interval=0.384-0.836). When, we redivided albuminuria by <10, 10-30 (high normal albuminuria), 30-300mg/g (microalbuminuria), and 300mg/g≤(macroalbuminuria), the odds ratio for high normal albuminuria and microalbuminuria was 1.52 and 2.24, respectively in the presence of HTN, however, high normal albuminuria was not associated with HTN control.

CONCLUSIONS

In conclusion, albuminuria within the high normal range was associated with the prevalence of HTN in South Korean patients with type 2 DM.

Delivering improved management and outcomes in diabetic kidney disease in routine clinical care

Aim

To examine the impact of service re-design on management and outcomes in type 2 diabetic patients with microalbuminuria and diabetic nephropathy.

Methods

The impact of implementation of evidence-based processes of care (blood pressure [BP] control, glycaemic control, renin-angiotensin-aldosterone system blockade, aspirin and cholesterol-lowering therapy, and smoking cessation) on progression to nephropathy in 338 microalbuminuria patients; and on death, doubling of serum creatinine, new end-stage renal failure (ESRF) and cardiovascular events in 127 nephropathy patients is described.

Results

Effective implementation of evidence-based processes of care improved surrogate outcomes (BP, HbA 1C and low density lipoprotein-cholesterol), was associated with little progression of microalbuminuria to nephropathy (6.1 per 100-patient-years), and in diabetic nephropathy patients were associated with rates of doubling of serum creatinine (1.4 per 100-patient-years), progression to ESRF (1.1 per 100-patient-years), cardiovascular events (3.2 per 100-patient-years) and mortality (2.2 per 100-patient-years) that compares favourably with landmark trials.

Conclusion

Service re-design in the management of type 2 diabetic kidney disease can deliver improved care and outcomes comparable with landmark trials in a routine clinical care setting.

Curcumin attenuates high glucose-induced podocyte apoptosis by regulating functional connections between caveolin-1 phosphorylation and ROS

AIM

Caveolin-1 (cav-1) is a major multifunctional scaffolding protein of caveolae. Cav-1 is primarily expressed in mesangial cells, renal proximal tubule cells and podocytes in kidneys. Recent evidence shows that the functional connections between cav-1 and ROS play a key role in many diseases. In this study we investigated whether regulating the functional connections between cav-1 and ROS in kidneys contributed to the beneficial effects of curcumin in treating diabetic nephropathy in vitro and in vivo.

METHODS

Cultured mouse podocytes (mpc5) were incubated in a high glucose (HG, 30 mmol/L) medium for 24, 48 or 72 h. Male rats were injected with STZ (60 mg/kg, ip) to induce diabetes. ROS generation, SOD activity, MDA content and caspase-3 activity in the cultured cells and kidney cortex homogenate were determined. Apoptotic proteins and cav-1 phosphorylation were analyzed using Western blot analyses.

RESULTS

Incubation in HG-containing medium time-dependently increased ROS production, oxidative stress, apoptosis, and cav-1 phosphorylation in podocytes. Pretreatment with curcumin (1, 5, and 10 μmol/L) dose-dependently attenuated these abnormalities in HG-treated podocytes. Furthermore, in HG-containing medium, the podocytes transfected with a recombinant plasmid GFP-cav-1 Y14F (mutation at a cav-1 phosphorylation site) exhibited significantly decreased ROS production and apoptosis compared with the cells transfected with empty vector. In diabetic rats, administration of curcumin (100 or 200 mg/kg body weight per day, ig, for 8 weeks) not only significantly improved the renal function, but also suppressed ROS levels, oxidative stress, apoptosis and cav-1 phosphorylation in the kidneys.

CONCLUSION

Curcumin attenuates high glucose-induced podocyte apoptosis in vitro and diabetic nephropathy in vivo partly through regulating the functional connections between cav-1 phosphorylation and ROS.

Subclinical Kidney Damage in Hypertensive Patients: A Renal Window Opened on the Cardiovascular System. Focus on Microalbuminuria

The kidney is one of the major target organs of hypertension.Kidney damage represents a frequent event in the course of hypertension and arterial hypertension is one of the leading causes of end-stage renal disease (ESRD).ESRD has long been recognized as a strong predictor of cardiovascular (CV) morbidity and mortality. However, over the past 20 years a large and consistent body of evidence has been produced suggesting that CV risk progressively increases as the estimated glomerular filtration rate (eGFR) declines and is already significantly elevated even in the earliest stages of renal damage. Data was supported by the very large collaborative meta-analysis of the Chronic Kidney Disease Prognosis Consortium, which provided undisputable evidence that there is an inverse association between eGFR and CV risk. It is important to remember that in evaluating CV disease using renal parameters, GFR should be assessed simultaneously with albuminuria.Indeed, data from the same meta-analysis indicate that also increased urinary albumin levels or proteinuria carry an increased risk of all-cause and CV mortality. Thus, lower eGFR and higher urinary albumin values are not only predictors of progressive kidney failure, but also of all-cause and CV mortality, independent of each other and of traditional CV risk factors.Although subjects with ESRD are at the highest risk of CV diseases, there will likely be more events in subjects with mil-to-moderate renal dysfunction, because of its much higher prevalence.These findings are even more noteworthy when one considers that a mild reduction in renal function is very common in hypertensive patients.The current European Society of Hypertension (ESH)/European Society of Cardiology (ESC) guidelines for the management of arterial hypertension recommend to sought in every patient signs of subclinical (or asymptomatic) renal damage. This was defined by the detection of eGFR between 30 mL/min/1.73 m² and 60 mL/min/1.73 m² or the presence of microalbuminuria (MAU), that is an amount of albumin in the urine of 30-300 mg/day or an albumin/creatinine ratio, preferentially on morning spot urine, of 30-300 mg/g.There is clear evidence that urinary albumin excretion levels, even below the cut-off values used to define MAU, are associated with an increased risk of CV events. The relationships of MAU with a variety of risk factors, such as blood pressure, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced CV risk conferred by MAU. Nonetheless, several studies showed that the association between MAU and CV disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between MAU and CV risk remain to be elucidated. The simple search for MAU and in general of subclinical renal involvement in hypertensive patients may enable the clinician to better assess absolute CV risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard CV risk factors.

Hypertension influences the exponential progression of inflammation and oxidative stress in streptozotocin-induced diabetic kidney

Objective:

To investigate the association of hypertension coexisting with diabetes mellitus with oxidative stress and inflammation in the kidneys of streptozotocin (STZ)-induced diabetic rats.

Materials and Methods:

Male Wistar rats were used for the experiments. Blood glucose (BG), urea, blood pressure (BP), and heart rate (HR) were analyzed before and 48 h after STZ injection. Further, these parameters were monitored up to 3 months of diabetes induction. Subsequently, the inflammatory markers (C-reactive protein, tumor necrosis factor-alpha, and nitrate) and oxidative stress markers were estimated after 3 months of diabetes induction in the kidney homogenate. Histological analysis of renal tissue was also carried out.

Results:

Linear elevation of BG, urea, mean arterial pressure (MAP), and HR was observed up to 3 months of diabetes induction. In the same manner, inflammatory and oxidative stress markers were also found to be significantly increased. Notably, the histological analysis revealed the signs of nephropathy such as increased mesangial cell number, thickness of basement membrane, and renal artery. Inflammatory and oxidative stress markers positively correlated with elevated BP and BG, but the correlation was better with BP rather than BG.

Conclusion:

Hypertension has a strong implication in the increased oxidative stress and inflammation of diabetic kidney at the very early stage of diabetes mellitus.

Screening and treatment by the primary care provider of common diabetes complications

Diabetes is the leading cause of end-stage renal disease, blindness, and nontraumatic lower-limb amputation. The largest reductions in cardiovascular events are seen when multiple risk factors are addressed simultaneously. The benefit of aspirin as secondary prevention in patients with previous stroke or myocardial infarction has been well established. Regular, dilated eye examinations are effective in detecting sight-threatening diabetic retinopathy and have been shown to prevent blindness. The use of appropriate tools and clinical examination/inspection provides greater than 87% specificity in detecting diabetic peripheral neuropathy. Early treatment of risk factors, including hypertension, hyperglycemia, and dyslipidemia can delay or prevent diabetic nephropathy.

Elevated fasting insulin level significantly increases the risk of microalbuminuria

BACKGROUND

Microalbuminuria is significantly associated with long-term prognosis in the general population as well as in diabetic patients. It is well known that insulin resistance (IR) can induce microalbuminuria, but an elevated fasting insulin level, which is an early clinical manifestation of IR, as a risk factor for microalbuminuria has not been clarified, so we investigated the association between fasting insulin level and the development of microalbuminuria in a general population.

METHODS AND RESULTS

A total of 1,192 non-diabetic Korean men without microalbuminuria in 2005 were followed until 2010. They were categorized into 3 groups according to their fasting insulin levels and monitored for the development of microalbuminuria. The incidence of microalbuminuria was compared among groups, and Cox proportional hazards models were used to calculate the hazard ratios for microalbuminuria according to the fasting insulin levels. During 4,013.0 person-years of follow-up, 51 incident cases of microalbuminuria developed between 2006 and 2010. The incidence of microalbuminuria increased in proportion to the fasting insulin levels (tertile 1: 1.8%, tertile 2: 4.5%, tertile 3: 6.5%, P<0.001). Hazard ratios for microalbuminuria also increased in proportion to the fasting insulin levels [tertile 1: reference, tertile 2: 2.44 (1.01-5.89), tertile 3: 3.30 (1.40-7.78), respectively, P for trend 0.013].

CONCLUSIONS

Elevated fasting insulin level was associated with the future development of microalbuminuria.

Is chronic kidney disease associated with diabetic retinopathy in Asian adults?

BACKGROUND

Diabetic nephropathy (DN) is commonly associated with diabetic retinopathy (DR). Few studies have demonstrated that chronic kidney disease (CKD) is associated with DR. However, it is not clear if CKD in the absence of albuminuria is associated with DR.

METHODS

We included 301 participants with diabetes (Chinese, Malay and Indian ethnicity aged ≥24 years who participated in the Singapore Prospective Study Program (2003-2007). Retinal photographs taken from both eyes were graded for DR using the modified Airlie House Classification. We examined the association of CKD defined by low estimated glomerular filtration rate (eGFR) (<60 mL/min per 1.73 m(2) , n = 54), and albuminuria (urinary albumin-to-creatinine ratio ≥30, n = 116) with any-DR (n = 99) in logistic regression models. We replicated this analysis in another independent population-based sample of Malay adults (n = 265) with similar methodology in Singapore.

RESULTS

41% of those with low-eGFR had normoalbuminuria. In separate models, while albuminuria was significantly associated with any-DR, low-eGFR was not significantly associated with any-DR. In a model combining both markers, compared to the referent group (normal-eGFR+normoalbuminuria), the odds ratio (OR) (95% confidence interval [CI]) of any-DR were: 2.33 (1.27-4.27) for normal-eGFR+albuminuria, 1.38 (0.49-3.91) for low-eGFR + normoalbuminuria, and 2.64 (1.05-6.63) for low-eGFR+albuminuria. Similar findings for any-DR were observed in the replication cohort of Malay persons (3.56 [1.49-8.54] for normal-eGFR+albuminuria, 1.69 (0.52-5.55) for low-eGFR+normoalbuminuria, 4.34 [1.68-11.24] for low-eGFR+albuminuria.

CONCLUSION

We demonstrated that CKD is associated with DR only in the presence of albuminuria suggesting that CKD is more likely related to diabetes in the presence of albuminuria.

Hypertension increases urinary excretion of immunoglobulin G, ceruloplasmin and transferrin in normoalbuminuric patients with type 2 diabetes mellitus

OBJECTIVE

Increased urinary excretion of certain plasma proteins, such as immunoglobulin G (IgG), ceruloplasmin and transferrin, with different molecular radii of 55 Å or less and different isoelectric points have been reported to precede development of microalbuminuria in patients who have diabetes mellitus with hypertension. We examined how hypertension affects these urinary proteins in a diabetic state.

METHODS

Excretion of IgG, ceruloplasmin, transferrin, albumin, α2-macroglobulin with a large molecular radius of 88 Å and N-acetylglucosaminidase in first-morning urine samples were measured in normoalbuminuric patients (urinary albumin-to-creatinine ratio < 15 mg/g) with hypertension and nondiabetes mellitus (group hypertension, n = 32), type 2 diabetes mellitus and normotension (group diabetes mellitus, n = 52) and type 2 diabetes mellitus and hypertension (group Both, n =45), and in age-matched controls (n = 72).

RESULTS

Urinary IgG, ceruloplasmin, transferrin, albumin and N-acetylglucosaminidase and estimated glomerular filtration rate (eGFR) were significantly elevated in groups diabetes mellitus and Both compared with controls. Furthermore, urinary IgG, ceruloplasmin and transferrin in group Both were significantly higher than those in group diabetes mellitus. These exhibited a positive and relatively strong association with eGFR compared with controls. No significant difference in urinary albumin or N-acetylglucosaminidase was found between the two diabetic groups. In contrast, group hypertension had elevated urinary transferrin without any changes in the other compounds. Urinary α2-macroglobulin did not differ among the four groups.

CONCLUSION

These findings suggest that normoalbuminuric diabetic patients without hypertension have both glomerular hemodynamic changes such as increased intraglomerular hydraulic pressure and altered proximal tubules, and that hypertension increases intraglomerular hydraulic pressure. Increased urinary IgG, ceruloplasmin and transferrin may reflect an increase in intraglomerular hydraulic pressure.

Intensive glucose control versus conventional glucose control for type 1 diabetes mellitus

BACKGROUND

Clinical guidelines differ regarding their recommended blood glucose targets for patients with type 1 diabetes and recent studies on patients with type 2 diabetes suggest that aiming at very low targets can increase the risk of mortality.

OBJECTIVES

To assess the effects of intensive versus conventional glycaemic targets in patients with type 1 diabetes in terms of long-term complications and determine whether very low, near normoglycaemic values are of additional benefit.

SEARCH METHODS

A systematic literature search was performed in the databases The Cochrane Library, MEDLINE and EMBASE. The date of the last search was December 2012 for all databases.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that had defined different glycaemic targets in the treatment arms, studied patients with type 1 diabetes, and had a follow-up duration of at least one year.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed studies for risk of bias, with differences resolved by consensus. Overall study quality was evaluated by the 'Grading of Recommendations Assessment, Development, and Evaluation' (GRADE) system. Random-effects models were used for the main analyses and the results are presented as risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes.

MAIN RESULTS

We identified 12 trials that fulfilled the inclusion criteria, including a total of 2230 patients. The patient populations varied widely across studies with one study only including children, one study only including patients after a kidney transplant, one study with newly diagnosed adult patients, and several studies where patients had retinopathy or microalbuminuria at baseline. The mean follow-up duration across studies varied between one and 6.5 years. The majority of the studies were carried out in the 1980s and all trials took place in Europe or North America. Due to the nature of the intervention, none of the studies could be carried out in a blinded fashion so that the risk of performance bias, especially for subjective outcomes such as hypoglycaemia, was present in all of the studies. Fifty per cent of the studies were judged to have a high risk of bias in at least one other category.Under intensive glucose control, the risk of developing microvascular complications was reduced compared to conventional treatment for a) retinopathy: 23/371 (6.2%) versus 92/397 (23.2%); RR 0.27 (95% CI 0.18 to 0.42); P < 0.00001; 768 participants; 2 trials; high quality evidence; b) nephropathy: 119/732 (16.3%) versus 211/743 (28.4%); RR 0.56 (95% CI 0.46 to 0.68); P < 0.00001; 1475 participants; 3 trials; moderate quality evidence; c) neuropathy: 29/586 (4.9%) versus 86/617 (13.9%); RR 0.35 (95% CI 0.23 to 0.53); P < 0.00001; 1203 participants; 3 trials; high quality evidence. Regarding the progression of these complications after manifestation, the effect was weaker (retinopathy) or possibly not existent (nephropathy: RR 0.79 (95% CI 0.37 to 1.70); P = 0.55; 179 participants with microalbuminuria; 3 trials; very low quality evidence); no adequate data were available regarding the progression of neuropathy. For retinopathy, intensive glucose control reduced the risk of progression in studies with a follow-up duration of at least two years (85/366 (23.2%) versus 154/398 (38.7%); RR 0.61 (95% CI 0.49 to 0.76); P < 0.0001; 764 participants; 2 trials; moderate quality evidence), while we found evidence for an initial worsening of retinopathy after only one year of intensive glucose control (17/49 (34.7%) versus 7/47 (14.9%); RR 2.32 (95% CI 1.16 to 4.63); P = 0.02; 96 participants; 2 trials; low quality evidence).Major macrovascular outcomes (stroke and myocardial infarction) occurred very rarely, and no firm evidence could be established regarding these outcome measures (low quality evidence).We found that intensive glucose control increased the risk for severe hypoglycaemia, however the results were heterogeneous and only the 'Diabetes Complications Clinical Trial' (DCCT) showed a clear increase in severe hypoglycaemic episodes under intensive treatment. A subgroup analysis according to the baseline haemoglobin A1c (HbA1c) of participants in the trials (low quality evidence) suggests that the risk of hypoglycaemia is possibly only increased for patients who started with relatively low HbA1c values (< 9.0%). Several of the included studies also showed a greater weight gain under intensive glucose control, and the risk of ketoacidosis was only increased in studies using insulin pumps in the intensive treatment group (very low quality evidence).Overall, all-cause mortality was very low in all studies (moderate quality evidence) except in one study investigating renal allograft as treatment for end-stage diabetic nephropathy. Health-related quality of life was only reported in the DCCT trial, showing no statistically significant differences between the intervention and comparator groups (moderate quality evidence). In addition, only the DCCT published data on costs, indicating that intensive glucose therapy control was highly cost-effective considering the reduction of potential diabetes complications (moderate quality evidence).

AUTHORS' CONCLUSIONS

Tight blood sugar control reduces the risk of developing microvascular diabetes complications. The evidence of benefit is mainly from studies in younger patients at early stages of the disease. Benefits need to be weighed against risks including severe hypoglycaemia, and patient training is an important aspect in practice. The effects of tight blood sugar control seem to become weaker once complications have been manifested. However, further research is needed on this issue. Furthermore, there is a lack of evidence from RCTs on the effects of tight blood sugar control in older patient populations or patients with macrovascular disease. There is no firm evidence for specific blood glucose targets and treatment goals need to be individualised taking into account age, disease progression, macrovascular risk, as well as the patient's lifestyle and disease management capabilities.

Longitudinal prevalence of hypertension, proteinuria, and retinopathy in dogs with spontaneous diabetes mellitus

Background

The prevalence and progression of vascular complications of spontaneous diabetes mellitus (DM) in dogs have not been described.

Objectives

To investigate the effects of duration of disease, as estimated by time since DM diagnosis, and glycemic control on prevalence of systemic hypertension, proteinuria, and diabetic retinopathy in dogs with spontaneous DM.

Animals

Seventeen client‐owned dogs with spontaneous DM.

Methods

Prospective, longitudinal observational study. Dogs with DM of less than 1 year's duration were recruited and evaluated once every 6 months for 24 months. Recorded measures included indirect BP, urine albumin, protein and creatinine concentrations, serial blood glucose and serum fructosamine concentrations, ophthalmic examination, and a standardized behavioral questionnaire.

Results

Eleven dogs completed the 2‐year follow‐up period, during which the highest recorded prevalence of systolic and diastolic hypertension was 55 and 64%, respectively. Prevalence of microalbuminuria and elevated urine protein:creatinine ratio (UPC) ranged up to 73 and 55%, respectively. Prevalence of retinopathy ranged up to 20%. No significant effect of time since DM diagnosis or glycemic control was detected for any of the measures examined. Additionally, no significant associations between BP, urine albumin concentration, UPC and retinopathy were detected.

Conclusions and Clinical Relevance

With the exception of proteinuria, which was substantial in some cases, clinically deleterious diabetic vascular complications were not identified in dogs in this study.

Astragaloside IV attenuates glycated albumin-induced epithelial-to-mesenchymal transition by inhibiting oxidative stress in renal proximal tubular cells

In diabetic kidney disease (DKD), epithelial-to-mesenchymal transition (EMT) is a classic pathological process in tubular damage. Oxidative stress is considered to play an important role in DKD. Astragaloside IV (A-IV), one of the main active ingredients of Astragalus membranaceus, exhibits a wide range of biological activities. However, the effect of A-IV on regulating EMT in tubular cells is unclear. This study aims to determine whether A-IV could attenuate glycated albumin (GA)-induced EMT in the NRK-52E cell line by inhibiting oxidative stress. GA and A-IV-induced cytotoxicity were assayed by CCK-8. The intercellular reactive oxygen species (ROS) level was detected by H2DCFDA. The activity of NADPH oxidase was assayed by adding exogenous NADPH oxidase, and the superoxide dismutase (SOD) units were observed by NBT. We used a microscope to examine the morphology of the NRK-52E cell line. We conducted a wound healing assay to measure cell mobility. To determine mRNA and protein expressions of α-SMA and E-cadherin, we used real-time polymerase chain reaction (real-time PCR), immunofluorescence, and western blot analysis. A-IV significantly attenuated GA-induced amplification of ROS, lowered the increased level of NADPH oxidase activity, and elevated the decreased level of SOD units. The GA-induced NRK-52E cell line showed increased expression of α-SMA and decreased expression of E-cadherin in mRNA and protein levels, whereas A-IV alleviated the expression of α-SMA and increased the expression of E-cadherin. Our data demonstrate that GA could induce NRK-52E cell line EMT through oxidative stress. This effect could be attenuated by A-IV via regulation of the impaired redox balance.

Microalbuminuria as a risk predictor in diabetes: the continuing saga

OBJECTIVE The rationale for this study was to review the data on microalbuminuria (MA), an amount of albumin in the urine of 30-299 mg/day, in patients with diabetes in the context of cardiovascular risk and development of kidney disease. The objective was to review the pathophysiology of MA in patients with diabetes and review the data from trials regarding MA in the context of risk for cardiovascular events or kidney disease progression. RESEARCH DESIGN AND METHODS Data sources were all PubMed-referenced articles in English-language peer-reviewed journals since 1964. Studies selected had to have a minimum 1-year follow-up and be either a randomized trial linking MA to cardiovascular or kidney disease outcome, a meta-analysis/systematic review, or a large observational cohort study. RESULTS The data suggest that MA is a risk marker for cardiovascular events and possibly for kidney disease development. Its presence alone, however, does not indicate established kidney disease, especially if the estimated glomerular filtration rate is >60 mL/min/1.73 m(2). An increase in MA, when blood pressure and other risk factors are controlled, portends a poor prognosis for kidney outcomes over time. Early in the course of diabetes, aggressive risk factor management focused on glycemic and blood pressure goals is important to delay kidney disease development and reduce cardiovascular risk. CONCLUSIONS MA is a marker of cardiovascular disease risk and should be monitored per guidelines once or twice a year for progression to macroalbuminuria and kidney disease development, especially if plasma glucose, lipids, and blood pressure are at guideline goals.

Lower levels of total HDL and HDL3 cholesterol are associated with albuminuria in normoalbuminuric Type 1 diabetic patients

BACKGROUND

Previous studies have suggested a positive association between dyslipidemia and chronic kidney disease, but sparse data are available on the relation of lipids and urinary albumin excretion rate (UAE) in normoalbuminuric patients with normal renal function.

AIM

The aim of this study was to evaluate the associations of serum lipids, including total, LDL, HDL, HDL2, HDL3 cholesterol, and triglyceride levels with UAE in normoalbuminuric Type 1 diabetic (T1D) patients.

METHODS

Study included 313 normoalbuminuric T1D patients with normal renal function and before any interventions with statins, ACE inhibitors or angiotensin II receptor blockers. Subjects were classified as low-normoalbuminuric (UAE<11.0 mg/24h) or high-normoalbuminuric (UAE≥11.0 mg/24h) based on median UAE of at least two 24- h urine collections. Correlations and multiple linear regressions analysis were performed to identify relationships between serum lipids and UAE in normoalbuminuric subjects.

RESULTS

Total HDL (p=0.02) and HDL3 cholesterol (p=0.01) levels were higher in low-normoalbuminuric subjects compared to high-normoalbuminuric subjects. In logistic regression analysis, after adjustment for age, sex, BMI, duration of diabetes and HbA1c, lower total HDL and HDL3 cholesterol levels were significantly associated with risk of higher UAE in our normoalbuminuric subjects (p≤0.01), with odds ratios of 0.34 to 0.43.

CONCLUSIONS

Elevated total HDL and HDL3 cholesterol levels are associated with lower UAE in normoalbuminuric T1D patients. However, whether the detection of elevated total HDL and HDL3 cholesterol levels in T1D patients has protective value for development of microalbuminuria needs to be assessed in further follow-up studies.

Longitudinal trends in use and costs of prescription medication in patients with type 1 diabetes: the impact of renal disease

OBJECTIVE

We estimated trends in prescription medication costs in out-patients with type 1 diabetes by various stages of diabetic nephropathy (DN), before the development of end-stage renal disease, between 1995 and 2005.

METHODS

Patients with normo- (n = 1,334), micro- (n = 206), and macroalbuminuria (n = 365) were identified from the Finnish Diabetic Nephropathy (FinnDiane) database. All purchases of medications were obtained from the Drug Prescription Register.

RESULTS

The costs levels differed significantly (P < 0.0001) between all groups. The estimated annual costs per patient in 1995 were €1,310 (95% CI 1,230-1,400), €1,450 (1,300-1,600), and €1,770 (1,620-1,930) in the normo-, micro-, and macroalbuminuria groups, respectively. The corresponding costs in 2005 were €1,950 (1,830-2,080), €2,110 (1,910-2,320), and €2,900 (2,650-3,180). The costs increased in all groups over time (P < 0.0001). The annual average increase was 3.5%, 3.3%, and 5.2% in each group. After the generic substitution was introduced, the costs of agents acting on the renin- angiotensin system and lipid-modifying agents dropped, although the number of users increased at the same time.

CONCLUSIONS

More severe stages of DN have a substantial impact on the costs, which suggests that early prevention and intensive treatment of renal disease may generate remarkable annual cost savings.

Comparison between the effect of glibenclamide and captopril on experimentally induced diabetic nephropathy in rats

HYPOTHESIS

This study aimed to elucidate the role of glibenclamide in the prevention of diabetic nephropathy and to compare it with a reference drug captopril in rats.

MATERIALS AND METHODS

There were two main groups of rats. Control group (I) was subdivided into four subgroups which received distilled water, vehicle of streptozotocin, glibenclamide or captopril. The streptozotocin-diabetic Group (II) was subdivided into three subgroups: untreated, glibenclamide or captopril treated. Measurement of arterial blood pressure, serum glucose and creatinine levels, 24 h urinary protein and albumin/creatinine ratio, kidney weight and its histological examination were done after 1, 2, 4, 8, 12 and 16 weeks of treatment.

RESULTS

In treated diabetic rats captopril reduced blood pressure significantly, while no significant change in the mean arterial blood pressure or blood glucose level was recorded with glibenclamide treatment. Glibenclamide and captopril-treated diabetic rats showed significant decrease in serum creatinine level, urine volume, urinary protein excretion, albumin:creatinine ratio and kidney:body weight ratio compared with the diabetic non-treated group. Histological examination of diabetic kidneys treated with either glibenclamide or captopril showed reduced glomerular hypertrophy, glomerulosclerosis, tubular degeneration and interstitial fibrosis compared with untreated diabetic rats.

CONCLUSION

Glibenclamide attenuated some biochemical and histological changes produced by diabetic nephropathy, despite persistent hyperglycemia and hypertension.

Protective effects of leukemia inhibitory factor against oxidative stress during high glucose-induced apoptosis in podocytes

Leukemia inhibitory factor (LIF) is a pleiotropic glycoprotein belonging to the interleukin-6 family of cytokines. In kidney, LIF regulates nephrogenesis, involves in tubular regeneration, responds to pro- and anti-inflammatory stimuli, and so on. LIF also plays an essential role in protective mechanisms triggered by preconditioning-induced oxidative stress. Although LIF shows a wide range of biologic activities, effects of LIF on high glucose-induced oxidative stress in podocytes remain unclear. The aim of the study was to assess whether LIF can attenuate high glucose-induced apoptosis in podocytes. The result of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated that LIF protected podocytes against high glucose-induced cytotoxicity. The flow cytometry assay showed that LIF attenuated high glucose-induced apoptosis in podocytes. Meanwhile, the result of flow cytometric assay gave the clear indication that LIF decreased high glucose-induced elevated level of reactive oxygen species (ROS). The measurement of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase (SOD), malondialdehyde (MDA), and caspase-3 activity levels showed that LIF attenuated the high glucose-induced decreased level of SOD and elevated level of NADPH oxidase, MDA and caspase-3 activity. These results may provide potential therapy for diabetic nephropathy in the future.

Hepatitis C virus infection and kidney disease: a meta-analysis

BACKGROUND AND OBJECTIVES

Hepatitis C virus (HCV) infection and kidney disease are both highly prevalent diseases. The association between HCV and GN has been supported by previous research but little is known about the relationship between HCV and kidney disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A systematic review of the published medical literature was conducted to determine if HCV is associated with increased likelihood of kidney disease in the general population. A random-effects model was used to generate a summary estimate of the relative risk for kidney disease, defined as an estimated GFR <60 ml/min per 1.73 m(2) or proteinuria, with HCV across the published studies.

RESULTS

Nine clinical studies (817,917 unique individuals) were identified. Pooling of study results demonstrated the absence of a relationship between HCV seropositive status and reduced estimated GFR (adjusted relative risk, 1.12; 95% confidence interval, 0.91, 1.38; P=0.28) according to the random-effects model. HCV seropositive serology was an independent and significant risk factor for proteinuria (defined by urine dipstick test or spot urine albumin/creatinine ratio) in the general population, with a summary estimate for adjusted relative risk of 1.47 (95% confidence interval, 1.12, 1.94; P=0.006). Significant heterogeneity was observed between studies (Ri=0.82; P value by Q test, <0.001).

CONCLUSIONS

This meta-analysis shows that HCV is independently associated with proteinuria but not with reduced GFR in the general population. Substantial heterogeneity occurred.

Psammomys obesus, a particularly important animal model for the study of the human diabetic nephropathy

The Psammomys obesus lives in natural desert habitat on low energy (LE) diet, however when maintained in laboratory conditions with high energy (HE) diet it exhibits pathological metabolic changes resembling those of type 2 diabetes. We have evaluated and correlated the histopathology, metabolic and functional renal alterations occurring in the diabetic Psammomys. Renal function determined by measuring glomerular filtration rate (GFR), protein excretion, protein/creatinine ratio and morpho-immunocytochemical evaluations were performed on HE diet diabetic animals and compared to LE diet control animals. The diabetic animals present a 54% increase in GFR after one month of hyperglycemic condition and a decrease of 47% from baseline values after 4 months. Protein excretion in diabetic animals was 5 folds increased after 4 months. Light microscopy showed an increase in glomeruli size in the diabetic Psammomys, and electron microscopy and immunocytochemical quantitative evaluations revealed accumulation of basement membrane material as well as frequent splitting of the glomerular basement membrane. In addition, glycogen-filled Armanni-Ebstein clear cells were found in the distal tubules including the thick ascending limbs of the diabetic animals. These renal complications in the Psammomys, including changes in GFR with massive proteinuria sustained by physiological and histopathological changes, are very similar to the diabetic nephropathy in human. The Psamommys obesus represents therefore a reliable animal model of diabetic nephropathy.

High glucose concentration affects the oxidant-antioxidant balance in cultured mouse podocytes

Hyperglycemia is well-recognized and has long-term complications in diabetes mellitus and diabetic nephropathy. In podocytes, the main component of the glomerular barrier, overproduction of reactive oxygen species (ROS) in the presence of high glucose induces dysfunction and increases excretion of albumin in urine. This suggests an impaired antioxidant defense system has a role in the pathogenesis of diabetic nephropathy. We studied expression of NAD(P)H oxidase subunits by Western blotting and immunofluorescence and the activities of the oxidant enzyme, NAD(P)H, and antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT), in mouse podocytes cultured in a high glucose concentration (30  mM). We found long-term (3 and 5 days) exposure of mouse podocytes to high glucose concentrations caused oxidative stress, as evidenced by increased expression of Nox4 and activities of NAD(P)H oxidase (Δ 182%) and SOD (Δ 39%) and decreased activities of GPx (Δ -40%) and CAT (Δ -35%). These biochemical changes were accompanied by a rise in intracellular ROS production and accumulation of hydrogen peroxide in extracellular space. The role of Nox4 in ROS generation was confirmed with Nox4 siRNA. In conclusion, high glucose concentration affects the oxidant-antioxidant balance in mouse podocytes, resulting in enhanced generation of superoxide anions and its attenuated metabolism. These observations suggest free radicals may play an important role in the pathogenesis of diabetic nephropathy.

Factor analysis of diabetic nephropathy in Chinese patients

OBJECTIVE

To investigate factors related to albuminuria in diabetic nephropathy (DN).

METHODS

Clinical data of 873 Chinese patients with type 2 diabetes were gathered retrospectively. Urinary albumin-creatinine-ratio was tested thrice for each patient before calculating its mean value for DN diagnosing and staging. Inter-relationship among variables was studied using factor analysis, and factor scores were compared and used as independent variables in regression models to identify the parameter clusters that predict the development and/or progression of DN.

RESULTS

Factor analysis reduced 21 original variables to eight unique factors, representing obesity, glycemic, C peptide, lipids, time, renal, blood pressure and metabolism status. Logistic regression revealed that presence of hyperuricemia/gout (OR=1.821, 95%CI 1.224-2.707), time factor (OR=1.404, 95%CI 1.194-1.651) and blood pressure factor (OR=1.424, 95%CI 1.216-1.668) were positively associated with DN, while C peptide factor (OR=0.816, 95%CI 0.691-0.963) was negatively associated with DN. Ordinal regression revealed another positively related lipid factor (OR=1.237, 95%CI 1.060-1.445) besides those determined in Logistic regression.

CONCLUSION

Hyperuricemia/gout, time, blood pressure and lipid factors are predictors of DN, while C peptide factor is negatively associated with the development and/or progression of DN.

A glimpse of various pathogenetic mechanisms of diabetic nephropathy

Diabetic nephropathy is a well-known complication of diabetes and is a leading cause of chronic renal failure in the Western world. It is characterized by the accumulation of extracellular matrix in the glomerular and tubulointerstitial compartments and by the thickening and hyalinization of intrarenal vasculature. The various cellular events and signaling pathways activated during diabetic nephropathy may be similar in different cell types. Such cellular events include excessive channeling of glucose intermediaries into various metabolic pathways with generation of advanced glycation products, activation of protein kinase C, increased expression of transforming growth factor β and GTP-binding proteins, and generation of reactive oxygen species. In addition to these metabolic and biochemical derangements, changes in the intraglomerular hemodynamics, modulated in part by local activation of the renin-angiotensin system, compound the hyperglycemia-induced injury. Events involving various intersecting pathways occur in most cell types of the kidney.

Microvascular complications and risk factors in patients with type 2 diabetes

AIM

To conduct a prospective study in patients with type 2 diabetes mellitus (T2DM) with no microvascular complications, analyzing the association between various baseline risk factors and development of microvascular complications at follow-up.

METHODS

A prospective, observational study in 376 patients with T2DM enrolled in 2004. The clinical end-point was urinary albumin excretion (UAE) > 30mg/24h and/or presence of retinopathy at follow-up in 2007. Baseline variables included age, gender, duration of T2DM, fasting plasma glucose, glycated hemoglobin (HbA(1c)), systolic and diastolic blood pressure, body weight, height, body mass index, waist circumference, total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), high sensitive C-reactive protein (hs-CRP), fibrinogen, UAE, creatinine, smoking status, exercise, alcohol consumption, use of hypoglycemic and lipid-lowering drugs, antihypertensive medications, and other data related to family history of diabetes and risk factors.

RESULTS

Ninety-five subjects (25.2%) developed a microvascular complication at the end of the follow-up period. In logistic regression analyses, the main independent risk factors were UAE >12mg/24h (odds ratio [OR]: 6.12; P=.000), hs-CRP> 3mg/L (OR: 3.00; P=.004), and hypertension (OR: 2.43; P=.023).

CONCLUSIONS

UAE levels higher than 12mg/24h, hs-CRP >3mg/L, and presence of hypertension were all independent risk factors for development of microvascular complications in patients with T2DM studied.

Characteristics of adolescents and youth with recent-onset type 2 diabetes: the TODAY cohort at baseline

CONTEXT

The Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) cohort represents the largest and best-characterized national sample of American youth with recent-onset type 2 diabetes.

OBJECTIVE

The objective of the study was to describe the baseline characteristics of participants in the TODAY randomized clinical trial.

DESIGN

Participants were recruited over 4 yr at 15 clinical centers in the United States (n = 704) and enrolled, randomized, treated, and followed up 2-6 yr.

SETTING

The study was conducted at pediatric diabetes care clinics and practices.

PARTICIPANTS

Eligible participants were aged 10-17 yr inclusive, diagnosed with type 2 diabetes for less than 2 yr and had a body mass index at the 85th percentile or greater.

INTERVENTIONS

After baseline data collection, participants were randomized to one of the following groups: 1) metformin alone, 2) metformin plus rosiglitazone, or 3) metformin plus a lifestyle program of weight management.

MAIN OUTCOME MEASURES

Baseline data presented include demographics, clinical/medical history, biochemical measurements, and clinical and biochemical abnormalities.

RESULTS

At baseline the cohort included the following: 64.9% were female; mean age was 14.0 yr; mean diabetes duration was 7.8 months; mean body mass index Z-score was 2.15; 89.4% had a family history of diabetes; 41.1% were Hispanic, 31.5% were non-Hispanic black; 38.8% were living with both biological parents; 41.5% had a household annual income of less than $25,000; 26.3% had a highest education level of parent/guardian less than a high school degree; 26.3% had a blood pressure at the 90th percentile or greater; 13.6% had a blood pressure at the 95th percentile or greater; 13.0% had microalbuminuria; 79.8% had a low high-density lipoprotein level; and 10.2% had high triglycerides.

CONCLUSIONS

The TODAY cohort is predominantly from racial/ethnic minority groups, with low socioeconomic status and a family history of diabetes. Clinical and biochemical abnormalities and comorbidities are prevalent within 2 yr of diagnosis. These findings contribute greatly to our understanding of American youth with type 2 diabetes.

Associations among systemic blood pressure, microalbuminuria and albuminuria in dogs affected with pituitary- and adrenal-dependent hyperadrenocorticism

BACKGROUND

Hypertension and proteinuria are medical complications associated with the multisystemic effects of long-term hypercortisolism in dogs with hyperadrenocorticism (HAC).

METHODS

This study investigated the relationships among adrenocorticotropic hormone (ACTH)-stimulation test results, systemic blood pressure, and microalbuminuria in clinically-healthy dogs (n = 100), in dogs affected with naturally occurring pituitary-dependent (PDH; n = 40), or adrenal-dependent hyperadrenocorticism (ADH; n = 30).

RESULTS

Mean systemic blood pressure was similar between clinically healthy dogs and dogs with HAC (p = 0.803). However the incidence of hypertension was highest in dogs with ADH (p = 0.017), followed by dogs with PDH, with the lowest levels in clinically healthy dogs (p = 0.019). Presence of microalbuminuria and albuminuria in clinically healthy dogs and dogs affected with HAC was significantly different (p < 0.001); incidences of albuminuria followed the same pattern of hypertension; highest incidence in dogs with ADH, and lowest level in clinically healthy dogs; but microalbuminuria showed a different pattern: clinically healthy dogs had highest incidences and dogs with ADH had lowest incidence. The presence of albuminuria was not associated with blood pressure values, regardless of whether dogs were clinically healthy or affected with ADH or PDH (p = 0.306).

CONCLUSIONS

Higher incidence of hypertension and albuminuria, not microalbuminuria was seen in dogs affected with HAC compared to clinically healthy dogs; incidence of hypertension and albuminuria was significantly higher in dogs affected with ADH compared to PDH. However, presence of albuminuria was not correlated with systemic blood pressure.