Biomarkers of Renal Disease and Progression in Patients with Diabetes

Is the urinary neutrophil gelatinase-associated lipocalin concentration in children and adolescents with type 1 diabetes mellitus different from that in healthy children?

Introduction

Diabetic kidney disease (DKD) is one of the major microvascular complications of type 1 diabetes mellitus (T1DM). Some studies suggest that changes of renal tubular components emerge before the glomerular lesions thus introducing the concept of diabetic tubulopathy with urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a potential marker of DKD. This concept was not confirmed in all studies.

Materials and methods

In 198 T1DM patients with median age 15 years and diabetes duration over one year, an albumin/creatinine ratio (ACR) was determined and uNGAL measured in spot urine sample. Urine samples for ACR and uNGAL were also collected in the control group of 100 healthy children of similar age.

Results

There was no significant difference in uNGAL concentration or uNGAL/creatinine between T1DM children and healthy subjects (6.9 (2.8-20.1) ng/mL vs 7.9 (2.9-21.0) ng/mL, P = 0.969 and 6.8 (2.2-18.4) ng/mg vs 6.5 (1.9-13.4) ng/mg, P = 0.448, respectively) or between T1DM subjects with albuminuria A2 and albuminuria A1 (P = 0.573 and 0.595, respectively). Among T1DM patients 168 (85%) had normal uNGAL concentrations, while in 30 (15%) patients uNGAL was above the defined cut-off value of 30.9 ng/mL. There was no difference in BMI, HbA1c and diabetes duration between patients with elevated uNGAL compared to those with normal uNGAL.

Conclusions

We found no significant difference in uNGAL concentration or uNGAL/creatinine between T1DM children and healthy subjects or between albuminuria A2 and albuminuria A1 T1DM subjects. Therefore, uNGAL should not be recommended as a single marker for detecting diabetic kidney disease in children and adolescents.

Transcriptomic analysis of diabetic kidney disease and neuropathy in mouse models of type 1 and type 2 diabetes

Diabetic kidney disease (DKD) and diabetic peripheral neuropathy (DPN) are common complications of type 1 (T1D) and type 2 (T2D) diabetes. However, the mechanisms underlying pathogenesis of these complications are unclear. In this study, we optimized a streptozotocin-induced db/+ murine model of T1D and compared it to our established db/db T2D mouse model of the same C57BLKS/J background. Glomeruli and sciatic nerve transcriptomic data from T1D and T2D mice were analyzed by self-organizing map and differential gene expression analysis. Consistent with prior literature, pathways related to immune function and inflammation were dysregulated in both complications in T1D and T2D mice. Gene-level analysis identified a high degree of concordance in shared differentially expressed genes (DEGs) in both complications and across diabetes type when using mice from the same cohort and genetic background. As we have previously shown a low concordance of shared DEGs in DPN when using mice from different cohorts and genetic backgrounds, this suggests that genetic background may influence diabetic complications. Collectively, these findings support the role of inflammation and indicate that genetic background is important in complications of both T1D and T2D.

From Diabetic Nephropathy to End-Stage Renal Disease: The Effect of Chemokines on the Immune System

Background

Diabetic nephropathy (DN) is a major cause of end-stage renal disease (ESRD), and there is growing evidence to support the role of immunity in the progression of DN to ESRD. Chemokines and chemokine receptors (CCRs) can recruit immune cells to sites of inflammation or injury. Currently, no studies have reported the effect of CCRs on the immune environment during the progression of DN to ESRD.

Methods

Differentially expressed genes (DEGs) from the GEO database were identified in DN patients versus ESRD patients. GO and KEGG enrichment analyses were performed using DEGs. A protein-protein interaction (PPI) network was constructed to identify hub CCRs. Differentially expressed immune cells were screened by immune infiltration analysis, and the correlation between immune cells and hub CCRs was also calculated.

Result

In this study, a total of 181 DEGs were identified. Enrichment analysis showed that chemokines, cytokines, and inflammation-related pathways were significantly enriched. Combining the PPI network and CCRs, four hub CCRs (CXCL2, CXCL8, CXCL10, and CCL20) were identified. These hub CCRs showed an upregulation trend in DN patients and a downregulation trend in ESRD patients. Immune infiltration analysis identified a variety of immune cells that underwent significant changes during disease progression. Among them, CD56bright natural killer cell, effector memory CD8 T cell, memory B cell, monocyte, regulatory T cell, and T follicular helper cell were significantly associated with all hub CCR correlation.

Conclusion

The effect of CCRs on the immune environment may contribute to the progression of DN to ESRD.

Prediction of the Short-Term Risk of New-Onset Renal Dysfunction in Patients with Type 2 Diabetes: A Longitudinal Observational Study

Background

Studies in the past decade have reported many novel biomarkers for predicting the new-onset or progression risk of renal dysfunction in patients with type 2 diabetes (T2D) based on the genomic, metabolomic, and proteomic technologies. These novel predictive markers, however, are difficult to be widely used in clinical practice over the short term due to their high technology content, instability, and high cost. This study was aimed at evaluating the associations of clinical features and six traditional renal markers with the short-term risk of new-onset renal dysfunction in patients with T2D.

Methods

This study involved 213 participants with T2D and normal renal function at baseline. The baseline levels of the albumin-to-creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), alpha-1-microglobulin-to-creatinine ratio (A1MCR), neutrophil gelatinase-associated lipocalin-to-creatinine ratio, transferrin-to-creatinine ratio (UTRF/Cr), and retinol-binding protein-to-creatinine ratio (URBP/Cr) were analyzed. Multivariate logistic models were established and validated.

Results

During the two-year follow-up period, 23.01% participants progressed to renal dysfunction. The basal levels of ACR, A1MCR, UTRF/Cr, and URBP/Cr were the independent risk factors of new-onset renal dysfunction (P < 0.05). Several logistic models incorporating clinical characteristics and these renal markers were constructed for predicting the short-term risk of new-onset renal dysfunction. Comparatively, the model including age, glycated hemoglobin (HbA1c), hypertension, ACR, A1MCR, UTRF/Cr, and URBP/Cr levels at baseline had the highest potential (C − index = 0.785, P < 0.001). This model was validated using the K-fold cross-validation method; the accuracy was 0.815 ± 0.013 in training sets and 0.784 ± 0.019 in validation sets, indicating a good consistency for predicting the new-onset renal dysfunction risk. Finally, a nomogram based on this model was constructed to provide a quantitative tool to assess the individualized risk of short-term new-onset renal dysfunction.

Conclusion

The model incorporating these markers and clinical features may have a high potential to predict the short-term risk of new-onset renal dysfunction.

A nomogram for predicting the risk of new-onset albuminuria based on baseline urinary ACR, orosomucoid, and HbA1c in patients with type 2 diabetes

OBJECTIVES

Numerous biomarkers have been shown to be associated with albuminuria. However, few of them are valuable separate predictors of albuminuria development. This study aimed to develop a model for predicting the short-term risk of new-onset albuminuria in normoalbuminuric patients with type 2 diabetes (T2D).

METHODS

213 patients with T2D who were normoalbuminuric at the baseline were enrolled in this study. Basal levels of clinical characteristics and renal biomarkers including urinary orosomucoid (alpha-1-acid-glycoprotein, UORM), neutrophil gelatinase-associated lipocalin, retinol-binding protein, alpha-1-microglobulin, transferrin, and albumin-to-creatinine ratio (ACR) were utilized to analyze the association with the short-term risk of new-onset albuminuria.

RESULTS

19.72% of normoalbuminuric subjects at baseline progressed to albuminuria over the 2-year follow-up period. Except for NGAL, the basal levels of the other five renal biomarkers were significantly associated with new-onset albuminuria risk in the univariate analysis. In the multivariate logistic regression analysis using Forward: LR method, a model incorporating UORM/Cr, ACR, and HbA1c was established. Comparatively, this model had a higher potential to predict new-onset albuminuria risk compared with the single use of renal markers. In the validation of this model performed by 5-fold cross-validation method, the accuracy of this model was 0.818 ± 0.008 in the training sets, 0.827 ± 0.062 in the test sets, indicating a good capability for assessing albuminuria risk. Finally, a nomogram based on this model was constructed to facilitate its use in clinical practice.

CONCLUSION

The combined analysis of UORM/Cr, ACR and HbA1c may be of potential value for predicting the short-term risk of new-onset albuminuria in such patients.

The Pathogenesis of End-Stage Renal Disease from the Standpoint of the Theory of General Pathological Processes of Inflammation

Chronic kidney disease can progress to end-stage chronic renal disease (ESRD), which requires the use of replacement therapy (dialysis or kidney transplant) in life-threatening conditions. In ESRD, irreversible changes in the kidneys are associated with systemic changes of proinflammatory nature and dysfunctions of internal organs, skeletal muscles, and integumentary tissues. The common components of ESRD pathogenesis, regardless of the initial nosology, are (1) local (in the kidneys) and systemic chronic low-grade inflammation (ChLGI) as a risk factor for diabetic kidney disease and its progression to ESRD, (2) inflammation of the classical type characteristic of primary and secondary autoimmune glomerulonephritis and infectious recurrent pyelonephritis, as well as immune reactions in kidney allograft rejection, and (3) chronic systemic inflammation (ChSI), pathogenetically characterized by latent microcirculatory disorders and manifestations of paracoagulation. The development of ChSI is closely associated with programmed hemodialysis in ESRD, as well as with the systemic autoimmune process. Consideration of ESRD pathogenesis from the standpoint of the theory of general pathological processes opens up the scope not only for particular but also for universal approaches to conducting pathogenetic therapies and diagnosing and predicting systemic complications in severe nephropathies.

Diabetic patients with chronic kidney disease: Non-invasive assessment of cardiovascular risk

The prevalence and burden of diabetes mellitus and chronic kidney disease on global health and socioeconomic development is already heavy and still rising. Diabetes mellitus by itself is linked to adverse cardiovascular events, and the presence of concomitant chronic kidney disease further amplifies cardiovascular risk. The culmination of traditional (male gender, smoking, advanced age, obesity, arterial hypertension and dyslipidemia) and non-traditional risk factors (anemia, inflammation, proteinuria, volume overload, mineral metabolism abnormalities, oxidative stress, etc.) contributes to advanced atherosclerosis and increased cardiovascular risk. To decrease the morbidity and mortality of these patients due to cardiovascular causes, timely and efficient cardiovascular risk assessment is of huge importance. Cardiovascular risk assessment can be based on laboratory parameters, imaging techniques, arterial stiffness parameters, ankle-brachial index and 24 h blood pressure measurements. Newer methods include epigenetic markers, soluble adhesion molecules, cytokines and markers of oxidative stress. In this review, the authors present several non-invasive methods of cardiovascular risk assessment in patients with diabetes mellitus and chronic kidney disease.

Potential Biomarkers in Diagnosis of Renal Acanthamoebiasis

Recent studies indicate that Acanthamoeba spp. may play a significant role in kidney dysfunction. The aim of the study was to examine the levels of kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and monocyte chemotactic protein 1 (MCP-1), as well as an activity of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively) in the kidneys of immunocompetent and immunosuppressed mice infected with Acanthamoeba spp. The levels of KIM-1, NGAL, and MCP-1 were analyzed by enzyme-linked immunosorbent assay (ELISA), and the activity of MMPs was determined by gelatin zymography. The elevated KIM-1 level was found in the kidneys of immunocompetent mice at the beginning of Acanthamoeba spp. infection. In the immunosuppressed mice, the KIM-1 level was statistically different. The statistically decreased NGAL level was found in the kidneys of immunocompetent mice compared to the uninfected mice. In the immunocompromised mice, we found statistically significant differences in MCP-1 levels between the uninfected and infected groups. There was an increase in the expression of both MMP-2 and MMP-9 in the kidneys of immunocompetent and immunosuppressed mice infected with Acanthamoeba spp. compared to the uninfected mice. The results indicate that KIM-1, NGAL, MCP-1, MMP-2, MMP-9, and MMP-9/NGAL might be promising biomarkers of renal acanthamoebiasis.

A Study of Association of Urinary Nephrin with Albuminuria in Patients with Diabetic Nephropathy

BACKGROUND AND AIMS

Diabetes mellitus and its complications are associated with high mortality and morbidity. Early detection is mandatory to improve quality of life years in patients with diabetic nephropathy. Hyperglycaemia disrupts podocytes, both structurally and functionally, leading to excretion of nephrin which is present in the glomerular filtration barrier. This study was undertaken to find out whether urinary nephrin is a better indicator of podocyte injury than albuminuria in patients with diabetic nephropathy.

METHODS

The study included 125 type 2 diabetes mellitus patients as cases categorized into three groups, depending upon albumin excretion. Age and sex matched 45 individuals without diabetes mellitus were chosen as the control group. The study protocol was approved by Institutional Ethics committee. Microalbumin was estimated by immunoturbidometry and urinary nephrin by ELISA. ANOVA and Tukey post-hoc tests were done to compare the data between the groups. Correlation studies were done. Odds ratio for nephrin was calculated. P value less than 0.05 was considered statistically significant. The statistical analyses were performed with SPSS software version 13.0.

RESULTS

The urinary nephrin was found to be proportionately increased from normoalbuminuria to macroalbuminuria and it was statistically significant, with sensitivity of 92.5% and specificity of 76.7%, the cut-off value of urinary nephrin was 97.5ng/mL.

CONCLUSION

Albuminuria has been used as an independent predictor of diabetic nephropathy. The statistical significant difference between the groups inferred that urinary nephrin excretion increased even in the stage of normoalbuminuria. Nephrin expression and its phosphorylation get altered by hyperglycaemia, contributing to renal damage. Nephrin was found to be a sensitive marker of early kidney dysfunction in diabetic patients.

The Role of Chemokines and Chemokine Receptors in Diabetic Nephropathy

Kidney function decline is one of the complications of diabetes mellitus and may be indicated as diabetic nephropathy (DN). DN is a chronic inflammatory disease featuring proteinuria and a decreasing glomerular filtration rate. Despite several therapeutic options being currently available, DN is still the major cause of end-stage renal disease. Accordingly, widespread innovation is needed to improve outcomes in patients with DN. Chemokines and their receptors are critically involved in the inflammatory progression in the development of DN. Although recent studies have shown multiple pathways related to the chemokine system, the specific and direct effects of chemokines and their receptors remain unclear. In this review, we provide an overview of the potential role and mechanism of chemokine systems in DN proposed in recent years. Chemokine system-related mechanisms may provide potential therapeutic targets in DN.

Multiplexed MRM-based protein quantification of putative prognostic biomarkers for chronic kidney disease progression in plasma

Current diagnostic measures for Chronic Kidney Disease (CKD) include detection of reduced estimated glomerular filtration rate (eGFR) and albuminuria, which have suboptimal accuracies in predicting disease progression. The disease complexity and heterogeneity underscore the need for multiplex quantification of different markers. The goal of this study was to determine the association of six previously reported CKD-associated plasma proteins [B2M (Beta-2-microglobulin), SERPINF1 (Pigment epithelium-derived factor), AMBP (Protein AMBP), LYZ (Lysozyme C), HBB (Hemoglobin subunit beta) and IGHA1 (Immunoglobulin heavy constant alpha 1)], as measured in a multiplex format, with kidney function, and outcome. Antibody-free, multiple reaction monitoring mass spectrometry (MRM) assays were developed, characterized for their analytical performance, and used for the analysis of 72 plasma samples from a patient cohort with longitudinal follow-up. The MRM significantly correlated (Rho = 0.5–0.9) with results from respective ELISA. Five proteins [AMBP, B2M, LYZ, HBB and SERPINF1] were significantly associated with eGFR, with the three former also associated with unfavorable outcome. The combination of these markers provided stronger associations with outcome (p < 0.0001) compared to individual markers. Collectively, our study describes a multiplex assay for absolute quantification and verification analysis of previously described putative CKD prognostic markers, laying the groundwork for further use in prospective validation studies.

Probiotic Soy Milk Consumption and Renal Function Among Type 2 Diabetic Patients with Nephropathy: a Randomized Controlled Clinical Trial

Diabetic nephropathy (DN) is one the most important complications of diabetes leading to end-stage renal disease. Dietary approaches have been considered to control of the kidney function deterioration among these patients. The aim of the present study was to determine the effects of fortified soy milk with Lactobacillus plantarum A7 on renal function biomarkers in type 2 DN patients. Forty-eight DN subjects were attended to this parallel randomized trial study. Participants were randomly assigned to consume a diet containing 200 mL/day probiotic soy milk in intervention group or soy milk in the control condition for 8 weeks. An inflammatory adipokine-Progranulin (PGRN), a cytokine receptor-soluble tumor necrosis factor receptor 1 (sTNFR1), and serum levels of Neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C (Cys-C) as the new renal function biomarkers were measured after 8 weeks of intervention according to the standard protocol. Our analysis showed that consumption of probiotic soy milk resulted in a significant reduction in the Cys-C and PGRN levels compared with the soy milk (P = 0.01) in the final adjusted model. In addition, after adjustment for age, weight, and energy intake, a marginally significant in the NGAL level was seen between two groups (P = 0.05). However, there was no significant differences on the sTNFR1concenteration between two groups (P = 0.06). Overall, intake of probiotic soy milk may have a beneficial effect on the renal function in patients with DN.

Inflammatory markers in children and adolescents with type 2 diabetes mellitus

This review examines the potential relationship between serum inflammation markers and type 2 diabetes mellitus (T2DM). Inflammation markers have been proposed as prognostic markers for the development of T2DM and its complications. Furthermore, modulation of the inflammatory process may offer future treatment strategies for T2DM. This review focuses on children and adolescents because there is usually little, if any, complications associated with other disease processes, use of medications, or active tobacco smoking. Furthermore, β-cell failure in young age cannot be solely explained by aging and exhaustion of β-cells due to insulin resistance. Pediatric studies have demonstrated that pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFNγ, PEDF, and fetuin A were increased in insulin resistance, while the anti-inflammatory cytokines adiponectin and omentin were decreased. Furthermore, TNF-α, fetuin A, FGF-21 were altered in obese children with T2DM suggesting a direct involvement in β-cell failure. Future studies focusing on children and adolescents may facilitate our understanding of T2DM as an inflammatory disease process.

Association of Interleukin-6 -174G/C Polymorphism with the Risk of Diabetic Nephropathy in Type 2 Diabetes: A Meta-analysis

Previous studies reported the association between interleukin-6 (IL-6) -174G/C gene polymorphism and the risk of diabetic nephropathy in type 2 diabetes mellitus (T2DN). However, the results remain controversial. In the present study, we conducted a meta-analysis to further examine this relationship between IL-6-174G/C gene polymorphism and T2DN. Three databases (PubMed, SinoMed and ISI Web of Science) were used to search clinical case-control studies about IL-6-174G/C polymorphism and T2DN published until Apr. 14, 2018. Fixed- or random-effects models were used to calculate the effect sizes of odds ratio (OR) and 95% confidence intervals (95% CI). Moreover, subgroup analysis was performed in terms of the excretion rate of albuminuria. All the statistical analyses were conducted using Stata 12.0. A total of 11 case-control studies were included in this study, involving 1203 cases of T2DN and 1571 cases of T2DM without DN. Meta-analysis showed that there was an association between IL-6-174G/C polymorphism and increased risk of T2DN under the allelic and recessive genetic models (G vs. C: OR=1.10, 95%CI 1.03-1.18, P=0.006; GG vs. CC+GC: OR=1.11, 95%CI 1.02-1.21 P=0.016). In the subgroup analysis by albuminuria, a significant association of IL-6-174G/C polymorphism with risk of T2DN was noted in the microalbuminuria group under the recessive model (OR=1.54, 95% CI 1.02-2.32, _P=0.038). In conclusion, this meta-analysis suggests that IL-6-174G/C gene polymorphism is associated with the risk of T2DN.

Evaluation of serum adiponectin levels in diabetic nephropathy

INTRODUCTION

Diabetic nephropathy is one of the major microvascular complications of diabetes mellitus. Adiponectin is an adipose tissue-derived cytokine that was identified in a human adipose tissue cDNA library. Serum adiponectin levels are found to be reduced in various pathological states including obesity, diabetes mellitus, ischaemic heart disease and arteriosclerosis obliterans and elevated in end stage renal diseases.

OBJECTIVE

to assess the level of plasma adiponectin as an early predictor of microvascular complications in patients with type 2 diabetes mellitus.

METHODS

44 patients with type 2 diabetes recruited from outpatient diabetes clinic in Kasr Alainy hospital. All patients were subjected to full laboratory work-up including: Fasting blood glucose and Post prandial blood glucose, Glycated haemoglobin A1C, Serum creatinine, Serum total cholesterol, Triglycerides, Low density lipoprotein, High density lipoprotein, C-reactive protein titre, serum adiponectin and Urinary albumin/creatinine (UAC) ratio.

RESULTS

The present study demonstrated that serum adiponectin concentrations had significant positive correlation with UAC ratio (r = 0.534, p = 0.0001). Adiponectin levels showed significant positive correlation in patients with diabetes and hypertension with microalbumiuria (p = .001) or normoalbumiuria (p = 0.004).

CONCLUSION

Serum adiponectin level can be a good predictor of diabetic nephropathy in patients with type 2 diabetes mellitus.

Safety of Permanent Pacemaker Implantation: A Prospective Study

Although pacemaker implantation is considered to be low risk, it is not exempt from complications and technical failures during the procedure, both in the short and long term, and the complications that such patients may present remain unknown. The aim has been to analyze the complication rates associated with permanent pacing and to identify if these differ between patients with or without previous antithrombotic therapy. We used a prospective, single center, observational study of 310 adult patients with indications of permanent pacing. They were hospitalized from 1 January to 31 December 2014 and followed up for 6 months after the pacemaker implant. The participants were distributed into two groups according to the antithrombotic therapy prior to the implant. The most frequent major complications were pneumothorax (3.87%) and lead dislodgement (8.39%), while superficial phlebitis (12.90%) and uncomplicated hematomas (22.58%) were presented as the most recurrent minor complications. Hematomas were the most frequent minor complication in the antithrombotic therapy cohort, and shoulder pain was reported as the most recurrent minor complication in the non-exposed group. Finding out about complications in pacemaker implants enables a complete view of the process, and hence the prioritization of actions aimed at improving safety and reducing associated risks.

Analysis of longitudinal semicontinuous data using marginalized two-part model

BACKGROUND

Connective tissue growth factor (CTGF), is a secreted matricellular factor that has been linked to increased risk of cardiovascular disease in diabetic subjects. Despite the biological role of CTGF in diabetes, it still remains unclear how CTGF expression is regulated. In this study, we aim to identify the clinical parameters that modulate plasma CTGF levels measured longitudinally in type 1 diabetic patients over a period of 10 years. A number of patients had negligible measured values of plasma CTGF that formed a point mass at zero, whereas others had high positive values of CTGF that were measured on a continuous scale. The observed combination of excessive zero and continuous positively distributed non-zero values in the CTGF outcome is referred to as semicontinuous data.

METHODS

We propose a novel application of a marginalized two-part model (mTP) extended to accommodate longitudinal semicontinuous data in which the marginal mean is expressed in terms of the covariates and estimates of their effect on the mean responses are generated. The continuous component is assumed to follow distributions that stem from the generalized gamma family whereas the binary measure is analyzed using logistic model and both have correlated random effects. Other approaches including the one- and two-part with uncorrelated and correlated random effects models were also applied and their estimates were all compared.

RESULTS

Our results using the mTP model identified intensive glucose control treatment and smoking as clinical factors that were associated with decreased and increased odds of observing non-zero CTGF values respectively. In addition, hemoglobin A1c, systolic blood pressure, and high density lipoprotein were all shown to be significant risk factors that contribute to increasing CTGF levels. These findings were consistently observed under the mTP model but varied with the distributions for the other models. Accuracy and precision of the mTP model was further validated using simulation studies.

CONCLUSION

The mTP model identified new clinical determinants that modulate the levels of CTGF in diabetic subjects. Applicability of this approach can be extended to other biomarkers measured in patient populations that display a combination of negligible zero and non-zero values.

Identification of Urinary Metabolite Biomarkers of Type 2 Diabetes Nephropathy Using an Untargeted Metabolomic Approach

Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus (DM). To discover early stage biomarkers of DN, untargeted liquid chromatography-mass spectrometry-based metabolomic analysis was performed in urine samples from healthy subjects and patients with micro- or macroalbuminuria due to nondiabetic disease (macro), type 2 DM without microalbuminuria (T2DM), and type 2 DM with microalbuminuria (T2DM+micro). Levels of four metabolites were significantly different among groups, and they were quantified in a larger group of 267 urine samples. Two metabolites were also discovered and validated in targeted metabolic study of amino acids. For diagnosis of nephropathy, N1-methylguanosine had the highest area-under-the-curve (AUC) value of 0.75 when compared to those of valine (0.68), xanthosine (0.67), and 7-methyluric acid (0.69). After combining fasting blood glucose and diastolic blood pressure (DBP) with N1-methylguanosine, the AUC increased to 0.987. To distinguish between T2DM and T2DM+micro conditions, xanthosine and N1-methylguanosine have AUC value of 0.612 and 0.624, respectively. After adjustment of HbA1c and DBP, AUC values of xanthosine and N1-methylguanosine increased to 0.716 and 0.723, respectively, and could be used to predict the development of nephropathy in T2DM patients.

Renal fat fraction and diffusion tensor imaging in patients with early-stage diabetic nephropathy

OBJECTIVE

To investigate the renal fat fraction and water molecular diffusion features in patients with early-stage DN using Dixon imaging and diffusion tensor imaging (DTI).

METHODS

Sixty-one type 2 diabetics (normoalbuminuria: n = 40; microalbuminuria: n = 21) and 34 non-diabetic volunteers were included. All participants received three-point Dixon imaging and DTI using a 3.0-T magnetic resonance imager. The fat fraction [FF] and DTI features [fractional anisotropy (FA), apparent diffusion coefficient (ADC), tract counts and length from DTI tractography] were collected. All image features were compared between cohorts using one-way ANOVA with Bonferroni post-hoc analysis.

RESULTS

Renal FF in the microalbuminuric group was significantly higher than in the normoalbuminuric and control groups (5.6% ± 1.3%, 4.7% ± 1.1% and 4.3% ± 0.5%, respectively; p < 0.001). Medullary FA in the microalbuminuric group was the lowest (0.31 ± 0.06) in all cohorts. The tract counts and length in the renal medulla were significantly lower in the microalbuminuric group than in the other two groups.

CONCLUSIONS

Dixon imaging and DTI are able to detect renal lipid deposition and water molecule diffusion abnormalities in patients with early-stage DN. Both techniques have the potential to noninvasively evaluate early renal impairment in type 2 diabetes.

KEY POINTS

• Dixon imaging demonstrated renal fat deposition in early-stage DN; • Renal fractional anisotropy decreased in patients with early-stage DN; • Renal tractography demonstrated reduced track counts and length in early-stage DN.

Albuminuria, serum creatinine, and estimated glomerular filtration rate as predictors of cardio-renal outcomes in patients with type 2 diabetes mellitus and kidney disease: a systematic literature review

BACKGROUND

Albuminuria, elevated serum creatinine and low estimated glomerular filtration rate (eGFR) are pivotal indicators of kidney decline. Yet, it is uncertain if these and emerging biomarkers such as uric acid represent independent predictors of kidney disease progression or subsequent outcomes among individuals with type 2 diabetes mellitus (T2DM). This study systematically examined the available literature documenting the role of albuminuria, serum creatinine, eGFR, and uric acid in predicting kidney disease progression and cardio-renal outcomes in persons with T2DM.

METHODS

Embase, MEDLINE, and Cochrane Central Trials Register and Database of Systematic Reviews were searched for relevant studies from January 2000 through May 2016. PubMed was searched from 2013 until May 2016 to retrieve studies not yet indexed in the other databases. Observational cohort or non-randomized longitudinal studies relevant to albuminuria, serum creatinine, eGFR, uric acid and their association with kidney disease progression, non-fatal cardiovascular events, and all-cause mortality as outcomes in persons with T2DM, were eligible for inclusion. Two reviewers screened citations to ensure studies met inclusion criteria.

RESULTS

From 2249 citations screened, 81 studies were retained, of which 39 were omitted during the extraction phase (cross-sectional [n = 16]; no outcome/measure of interest [n = 13]; not T2DM specific [n = 7]; review article [n = 1]; editorial [n = 1]; not in English language [n = 1]). Of the remaining 42 longitudinal study publications, biomarker measurements were diverse, with seven different measures for eGFR and five different measures for albuminuria documented. Kidney disease progression differed substantially across 31 publications, with GFR loss (n = 9 [29.0%]) and doubling of serum creatinine (n = 5 [16.1%]) the most frequently reported outcome measures. Numerous publications presented risk estimates for albuminuria (n = 18), serum creatinine/eGFR (n = 13), or both combined (n = 6), with only one study reporting for uric acid. Most often, these biomarkers were associated with a greater risk of experiencing clinical outcomes.

CONCLUSIONS

Despite the utility of albuminuria, serum creatinine, and eGFR as predictors of kidney disease progression, further efforts to harmonize biomarker measurements are needed given the disparate methodologies observed in this review. Such efforts would help better establish the clinical significance of these and other biomarkers of renal function and cardio-renal outcomes in persons with T2DM.

Effect of diacerein on renal function and inflammatory cytokines in participants with type 2 diabetes mellitus and chronic kidney disease: A randomized controlled trial

Diacerein seems to improve metabolic control and reduce inflammatory marker levels in individuals with type 2 diabetes mellitus (Type 2 DM), but for participants with chronic kidney disease (CKD) its effect is unknown. This study aimed to evaluate the effect of diacerein vs. placebo on urinary albumin/creatinine ratio (ACR), glomerular filtration rate (GFR), and inflammatory cytokines in type 2 DM participants with CKD. Blood pressure (BP) and metabolic control were secondary outcomes. This randomized, placebo-controlled, parallel trial of adjuvant treatment of type 2 DM with diacerein enrolled seventy-two participants with CKD, aged 30–80 years, with glycated hemoglobin levels from 53–97 mmol/mol (7.0–11.0%), receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and antidiabetic agents. Participants randomized to diacerein or placebo were followed-up up to 90 days. Both groups had a marked reduction in ACR, but there was no effect on glomerular filtration rate. While the diacerein group had reduced TNF-α levels at the 75th percentile with a borderline significance (P = 0.05), there were no changes in the IL levels at the 75^th percentile.

Diacerein prevented the increase in blood glucose to the level observed in the placebo group (P = 0.04), improving metabolic control by 74%, reducing 24-hour diastolic BP, nighttime systolic and diastolic BP compared to the placebo group. In conclusion, among patients with type 2 DM and CKD, diacerein does not have an effect on ACR or GFR, but slows metabolic control deterioration and is associated with lower nighttime systolic and diastolic blood pressure.

Trial registration: Brazilian Clinical Trials Registry (Registro Brasileiro de Ensaios Clinicos; ReBeC) U1111-1156-0255

Soluble plasma proteins ST2 and CD163 as early biomarkers of nephropathy in Swedish patients with diabetes, 15-34 years of age: a prospective cohort study

BACKGROUND

The aim of this study was to investigate plasma levels of sST2 and sCD163 to determine whether they at an early stage could predict development of diabetic nephropathy and/or diabetic retinopathy in patients at clinical onset.

METHODS

Patients diagnosed with diabetes mellitus at age 15-34 years between 1987 and 1988 (n = 220) were included. Data such as BMI, smoking, HbA1c and islet cell antibodies were collected at time of diagnosis. Within the 10 year follow-up period, 112 patients (51%) developed following diabetes related complications; retinopathy (n = 91), nephropathy (n = 12) or both (n = 9). Plasma concentrations of sST2 and sCD163 were measured at time of diagnosis and levels compared between different complication groups.

RESULTS

Plasma levels of sST2 were significantly higher in patients who later developed nephropathy (n = 21; 1012 [773-1493] pg/ml) compared to those who did not (n = 199; 723 [449-1084] pg/ml; p = 0.006). A tendency for higher plasma levels of sCD163 was observed but not statistically significant (p = 0.058).

CONCLUSIONS

sST2 and sCD163 show promise as potential biomarkers for the development of nephropathy already at clinical onset. sST2 and/or sCD163 could possibly be part of a biomarker panel aimed to find patients at high risk of developing nephropathy. Both markers need to be investigated in a larger prospective study.

Increased levels of inflammatory mediators and proinflammatory monocytes in patients with type I diabetes mellitus and nephropathy

AIMS

To investigate and describe the relationship between diabetic nephropathy and systemic inflammation in patients with type 1 diabetes mellitus (T1DM).

METHODS

Patients with T1DM, with or without reduced renal function due to diabetic nephropathy, were included. Differences in inflammatory mediators, adhesion molecules, markers of endothelial dysfunction and subsets of monocytes were studied in patients with mean disease duration of 31years.

RESULTS

Patients with T1DM with and without renal failure were compared. Patients with nephropathy had increased plasma levels of proinflammatory monocytes, as well as circulatory PAI-1, syndecan-1, VEGF, IL-1β, IL-1Ra and CCL4. Peripheral blood mononuclear cells from patients with nephropathy numerically increased soluble ICAM and PAI-1 in co-culture with primary endothelial cells compared to cells from patients without nephropathy.

CONCLUSIONS

T1DM patients with kidney failure have higher levels of proinflammatory monocytes and circulatory inflammatory mediators compared to patients with T1DM alone. The results highlight the importance of inflammation and endothelial dysfunction in diabetic nephropathy with reduced GFR.

Interleukin-6 gene polymorphisms correlate with the progression of nephropathy in Chinese patients with type 2 diabetes: A prospective cohort study

AIMS

Interleukin-6 (IL-6), an inflammatory cytokine, is considered a candidate gene possibly involved in susceptibility to nephropathy in diabetes. This study aimed to examine whether IL-6 polymorphisms predict the progression of nephropathy in a prospective Chinese cohort of patients with type 2 diabetes.

METHODS

A total of 568 type 2 diabetic patients with normoalbuminuria at baseline were followed up for a mean of 5.3±1.5years. Urinary albumin-to-creatinine ratio (ACR) ⩾30mg/g in two consecutive urine tests were defined as progression to diabetic nephropathy (n=143). Five polymorphisms of IL-6 gene, rs1800795, rs1800796, rs1524107, rs2069837, and rs2069840, were genotyped. Cox proportional hazard models were used to estimate hazard ratio (HR) and 95% CI of progression to diabetic nephropathy under different genetic models.

RESULTS

Almost all patients (99.6%) carried the rs1800795 GG homozygous genotypes. In the Cox proportional models adjusted for multiple covariates, the HR under recessive model was 2.02 for rs1800796 GG (vs. CC+CG, 95% CI: 1.08-3.75, p=0.027), 2.37 for rs2069837 GG (vs. AA+AG, 95% CI: 1.15-4.87, p=0.019), and 2.08 for rs1524107 CC (vs. TT+TC, 95% CI: 1.12-3.89, p=0.021). These associations remained significant for rs1800796 and rs1524107 after correction for multiple testing (α=0.017). Overall, our results suggest that rs1800796 GG and rs1524107 CC homozygous genotypes may confer a greater risk for development of nephropathy in type 2 diabetes.

CONCLUSIONS

IL-6 gene polymorphisms rs1800796 and rs1524107 may serve as predictors of progression of nephropathy in Chinese patients with type 2 diabetes.

Progressive development of renal cysts in glycogen storage disease type I

Glycogen storage disease type I (GSDI) is a rare metabolic disease due to glucose-6 phosphatase deficiency, characterized by fasting hypoglycemia. Patients also develop chronic kidney disease whose mechanisms are poorly understood. To decipher the process, we generated mice with a kidney-specific knockout of glucose-6 phosphatase (K.G6pc^-/- mice) that exhibited the first signs of GSDI nephropathy after 6 months of G6pc deletion. We studied the natural course of renal deterioration in K.G6pc^-/- mice for 18 months and observed the progressive deterioration of renal functions characterized by early tubular dysfunction and a later destruction of the glomerular filtration barrier. After 15 months, K.G6pc^-/- mice developed tubular-glomerular fibrosis and podocyte injury, leading to the development of cysts and renal failure. On the basis of these findings, we were able to detect the development of cysts in 7 out of 32 GSDI patients, who developed advanced renal impairment. Of these 7 patients, 3 developed renal failure. In addition, no renal cysts were detected in six patients who showed early renal impairment. In conclusion, renal pathology in GSDI is characterized by progressive tubular dysfunction and the development of polycystic kidneys that probably leads to the development of irreversible renal failure in the late stages. Systematic observations of cyst development by kidney imaging should improve the evaluation of the disease's progression, independently of biochemical markers.

Cascade regulation of PPARγ(2) and C/EBPα signaling pathways by celastrol impairs adipocyte differentiation and stimulates lipolysis in 3T3-L1 adipocytes

OBJECTIVE

Celastrol, a triterpene from the root bark of the Chinese medicinal plant Tripterygium wilfordii, has been shown to exhibit anti-oxidant, anti-inflammatory, anti-cancer and insecticidal activities. Also, it has been demonstrated that celastrol has obesity-controlling effects in diet-induced obesity mice. However, direct evidence that celastrol contributes to the development of adipocyte differentiation and lipolysis has not been fully elucidated. Moreover, no previous studies have evaluated whether celastrol may regulate adipogenic transcriptional markers in adipocytes.

MATERIALS/METHODS

In order to address the questions above, we extended previous observations and investigated in vitro celastrol signaling study whether celastrol may regulate differentiation, lipolysis and key adipogenic transcriptional pathways in 3T3-L1 adipocytes.

RESULTS

Treatment of celastrol not only inhibited adipocyte differentiation (lipid accumulation, glyceraldehyde-3-phosphate dehydrogenase activity and triglyceride content) but also increased lipolysis (glycerol release and free fatty acid release) in 3T3-L1 adipocytes. In addition, all celastrol-regulated functional activities were controlled by PPARγ(2) and C/EBPα signaling pathways in duration of celastrol's treatment in 3T3-L1 adipocytes.

CONCLUSION

Our initial data from in vitro celastrol signaling studies suggest novel insights into the role of PPARγ(2) and C/EBPα as probable mediators of the action of celastrol in regulating adipocyte differentiation and lipolysis in 3T3-L1 adipocytes.

The role of IL-18 in type 1 diabetic nephropathy: The problem and future treatment

Diabetic vascular complication is a leading cause of diabetic nephropathy, a progressive increase in urinary albumin excretion coupled with elevated blood pressure leading to declined glomerular filtration and eventually end stage renal failure. There is growing evidence that activated inflammation is contributing factor to the pathogenesis of diabetic nephropathy. Meanwhile, IL-18, a member of the IL-1 family of inflammatory cytokines, is involved in the development and progression of diabetic nephropathy. However, the benefits derived from the current therapeutics for diabetic nephropathy strategies still provide imperfect protection against renal progression. This imperfection points to the need for newer therapeutic agents that have potential to affect primary mechanisms contributing to the pathogenesis of diabetic nephropathy. Therefore, the recognition of IL-18 as significant pathogenic mediators in diabetic nephropathy leaves open the possibility of new potential therapeutic targets.

Immune Cells and Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) is a serious complication of diabetes. At its core, DN is a metabolic disorder which can also manifest itself in terms of local inflammation in the kidneys. Such inflammation can then drive the classical markers of fibrosis and structural remodeling. As a result, resolution of immune-mediated inflammation is critical towards achieving a cure for DN. Many immune cells play a part in DN, including key members of both the innate and adaptive immune systems. While these cells were classically understood to primarily function against pathogen insult, it has also become increasingly clear that they also serve a major role as internal sensors of damage. In fact, damage sensing may serve as the impetus for much of the inflammation that occurs in DN, in a vicious positive feedback cycle. Although direct targeting of these proinflammatory cells may be difficult, new approaches that focus on their metabolic profiles may be able to alleviate DN significantly, especially since dysregulation of the local metabolic environment may well be responsible for triggering inflammation to begin with. In this review, the authors consider the metabolic profile of several relevant immune types and discuss their respective roles.