Diabetic nephropathy - Epidemiology in Asia and the current state of treatment

Correlation of Urinary Neutrophil Gelatinase with the Histopathological Extent of Kidney Damage in Patients with Diabetic Nephropathy

Diabetic nephropathy (DN), a leading cause of chronic kidney disease, is known to develop in around 40% of patients with diabetes. NGAL, a biomarker expressed by the tubular epithelium, has been evaluated in both acute and chronic kidney injury. However, kidney damage revealed by the histology of renal tissue core biopsies has not been quantified by morphometry and its correlation with urinary NGAL (uNGAL) has not been studied. Our objective was to compare levels of uNGAL with the extent of kidney damage in the histopathological results of morphometry in patients with DN. This prospective analytical study was conducted in a tertiary hospital. Urine samples of 42 patients were collected and freeze-dried. uNGAL was estimated through a chemiluminescent microparticle immunoassay. Pearson's correlation coefficients between kidney damage quantified by morphometry and NGAL values were examined. The correlation of uNGAL with the percentage of acute tubular injury assessed by morphometry in the renal core was 7.35% (P = 0.64). uNGAL had the highest correlation with inflammation (r = 54.2%; P = 0.002). Another parameter with a significant correlation was glomerular sclerosis with r = 35.6% (95% confidence interval: 10%-60%) and an associated P = 0.02. UNGAL was strongly correlated with inflammatory kidney damage in patients with DN.

Management of diabetic kidney disease: where do we stand?: A narrative review

Diabetic kidney disease is the leading cause of chronic kidney disease and end-stage renal disease. The pathogenesis and risk factors for the development of diabetic kidney disease are complex and multifaceted, resulting in glomerular hypertrophy, tubulointerstitial inflammation, and fibrosis. The clinical staging progresses over 5 stages from early hyperfiltration to overt nephropathy. Primary prevention like glycaemic control, control of blood pressure, treatment of dyslipidemia and lifestyle modifications have shown promising benefits. Despite widespread research, very few drugs are available to retard disease progression. More literature and research are needed to fill these lacunae. We carried out a literature search focusing on newer updates in diabetic kidney disease pathophysiology, diagnosis and management using a PubMed search through the National library of medicine using keywords "Diabetic kidney disease," and "Diabetic nephropathy" till the year 2022. We have summarized the relevant information from those articles.

The Association Between Age of Onset of Type 2 Diabetes and the Long-term Risk of End-Stage Kidney Disease: A National Registry Study

OBJECTIVE

The long-term risk of end-stage kidney disease (ESKD) in type 2 diabetes is poorly described, as is the effect that younger age of diabetes onset has on this risk. Therefore, we aimed to estimate the effect of age of onset on the cumulative incidence of ESKD from onset of type 2 diabetes.

RESEARCH DESIGN AND METHODS

This study included 1,113,201 people with type 2 diabetes registered on the Australian National Diabetes Services Scheme (NDSS) followed from 2002 until 2013. The NDSS was linked to the Australia and New Zealand Dialysis and Transplant Registry and the Australian National Death Index.

RESULTS

Between 2002 and 2013, there were 7,592 incident cases of ESKD during 7,839,075 person-years of follow-up. In the first 10-15 years following the onset of diabetes, the incidence of ESKD was highest in those with an older age of onset of diabetes, whereas over longer durations of diabetes, the incidence of ESKD became higher in those with younger-onset diabetes. After 40 years of diabetes, the cumulative incidence of ESKD was 11.8% and 9.3% in those diagnosed with diabetes at ages 10-29 and 30-39 years, respectively. When death from ESKD without renal replacement therapy was included, the incidence of ESKD remained higher in older-onset diabetes for the initial 20 years, with no clear effect of age thereafter.

CONCLUSIONS

The long-term risk of ESKD in type 2 diabetes is high, which disproportionately affects those with younger onset of diabetes because they are more likely to survive to longer diabetes durations.

Role of omentin 1 and IL-6 in type 2 diabetes mellitus patients with diabetic nephropathy

AIMS

Diabetic nephropathy (DN) is one of the major chronic vascular complication of T2DM and leading cause of end-stage renal disease. Inflammation is one of the proposed pathway which explains microvascular complications in T2DM but exact mechanism is still unclear. Omentin-1 is an anti-inflammatory adipokine which promotes insulin signaling. IL-6 is a multifunctional cytokine having role in immune and inflammatory responses. The present study was conducted to elucidate the role of omentin-1 and IL-6 in the pathogenesis of DN and its association with insulin resistance. We aimed to assess and compare the serum levels of omentin-1 and IL-6 in T2DM patients with and without DN.

MATERIALS & METHODS

Our study comprised of 2 groups of 41 each. Group A (controls) included T2DM without nephropathy patients and group B (cases) included T2DM nephropathy patients. Parameters studied were serum omentin-1, insulin, IL-6, fasting blood glucose, urea, creatinine, lipid profile, HOMA-IR, eGFR and BMI.

RESULTS & CONCLUSION

Omentin-1 (p=0.03) was significantly decreased; concomitantly, significant increase in levels of insulin (p=0.004), IL-6 (p=0.023) and HOMA-IR (p=0.0004) were found in cases compared to controls. Bivariate analysis showed eGFR correlating positively with omentin-1 and negatively with insulin in the study population. Our study results, based on serum omentin-1 and IL-6 data suggest important role played by inflammatory mechanism and insulin resistance in the pathogenesis of diabetic nephropathy in type 2 diabetes mellitus patients.

The classic signalling and trans-signalling of interleukin-6 are both injurious in podocyte under high glucose exposure

Interleukin‐6 (IL‐6) is a multifunctional cytokine that employs IL‐6 classic and trans‐signalling pathways, and these two signal channels execute different or even opposite effects in certain diseases. As a cardinal event of diabetic kidney disease (DKD), whether the podocyte abnormalities are associated with IL‐6 signalling, especially classic or trans‐signalling respectively, remains unclear. In this study, we identified that the circulatory IL‐6, soluble IL‐6R (sIL‐6R) and soluble glycoprotein 130 (sgp130) levels are elevated in patients with DKD. The expressions of membrane‐bound IL‐6R (mIL‐6R), sIL‐6R and gp130 are enhanced in kidney cortex of diabetic mice accompanying with activated STAT3 by tyrosine 705 residue phosphorylation, while not serine 727. Above data infer both classic signalling and trans‐signalling of IL‐6 are activated during DKD. In cultured podocyte, high glucose (HG) up‐regulates the expression of mIL‐6R and gp130, as well as STAT3 tyrosine 705 phosphorylation, in a time‐dependent manner. Entirely blocking IL‐6 signalling by gp130 shRNA, gp130 or IL‐6 neutralizing antibodies attenuates HG‐induced podocyte injury. Interestingly, either inhibiting IL‐6 classic signalling by mIL‐6R shRNA or suppressing its trans‐signalling using sgp130 protein dramatically alleviates HG‐induced podocyte injury, suggesting both IL‐6 classic signalling and trans‐signalling play a detrimental role in HG‐induced podocyte injury. Additionally, activation of IL‐6 classic or trans‐signalling aggravates podocyte damage in vitro. In summary, our observations demonstrate that the activation of either IL‐6 classic or trans‐signalling advances podocyte harming under hyperglycaemia. Thus, suppressing IL‐6 classic and trans‐signalling simultaneously may be more beneficial in podocyte protection and presents a novel therapeutic target for DKD.

Diagnostic efficacy of random albumin creatinine ratio for detection of micro and macro-albuminuria in type 2 diabetes mellitus

OBJECTIVES

To compare a less cumbersome random albumin creatinine ratio (RACR) with 24-hour urinary albumin excretion (UAE) for detection of renal damage in patients with type 2 diabetes mellitus (T2DM).

METHODS

This retrospective study performed between March 2013 and June 2014 at the Department of Pathology, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia included 122 patients (mean age 54 ± 15, 104 females and 18 males) with T2DM. Urine albumin levels of less than 30 mg/g was considered normal, from 30-300 mg/g considered as micro-albuminuria, and over 300 mg/g considered as macro-albuminuria.

RESULTS

Concordance between the 2 assays was observed in 114 (93.4%) samples. The sensitivity of RACR assay was 100%, specificity was 91.3% with a positive predictive value (PPV) of 95%, and a negative predictive value (NPV) of 100% in micro-albuminuria range. For macro-albuminuria, RACR had a sensitivity of 100%, specificity of 94.1% with PPV of 94% and NPV of 100%. Receiver operating characteristic (ROC) curves analysis cut-off values of 40 mg/g-300 mg/g for micro- and greater than 300 mg/g for macro-albuminuria revealed 100% sensitivity, 97.5% specificity, 95% PPV, and 100% NPV for micro-albuminuria, and 100% sensitivity, 94% specificity, 76% PPV, and 100% NPP for macro-albuminuria. The area under the curve for micro-albuminuria was 100% and 98.2% for macro-albuminuria.

CONCLUSION

Performance of RACR was comparable to 24 hour UAE assay particularly in excluding renal damage in T2DM.

Prevalence of diabetic nephropathy in Type 2 Diabetes Mellitus in rural communities of Guanajuato, Mexico. Effect after 6 months of Telmisartan treatment

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Diabetic Nephropathy prevalence was determined in Mexican rural communities.

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We evaluated ARB treatment over 6 months in patients with Diabetic Nephropathy.

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We found a higher prevalence of DN than reported in Mexican National Health Survey.

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Subjects receiving ARB showed significant improvement in all parameters studied.

Objective

To determine the prevalence of Diabetic Nephropathy (DN) in patients with type 2 Diabetes Mellitus (T2DM) with over 5 years of evolution in rural communities of Guanajuato, Mexico, and evaluate the effects of an ARB treatment over 6 months in patients with DN.

Materials and methods

Patients of both sexes, 38–86 years, T2DM over 5 years of evolution and diagnosed with arterial hypertension (HT) after T2DM incidence. Monthly determination of microalbuminuria (MA), lipids, glucose, serum creatinine, and glycated hemoglobin (HbA1c). Estimated glomerular filtration rate (eGFR) by the Modification of Diet in Renal Disease (MDRD) formula. A dose of 80 mg of Telmisartan was administered daily over 6 months.

Results

The total adult population of two rural communities (3609 subjects) was studied, 335 subjects had T2DM, among them 80 (with a prevalence of 24%) had DN and HT. Sixty-seven patients received Telmisartan, and showed significant improvement in all parameters studied.

Conclusions

A higher prevalence of DN than that reported in the Mexican National Health Survey (ENSANUT) was found. Further research is required in a larger population sample in order to confirm the results of Telmisartan treatment.

Renal histology in diabetic nephropathy: A novel perspective

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease all over the world. India has a high incidence and prevalence of diabetes and >30% have nephropathy. Recently, a histological classification has been proposed. This study analyzed the renal histology in 114 diabetic patients with renal dysfunction. Nearly 75% of patients had DN. Fifty five (63.95%) were males. Mean duration of diabetes was 7.04 ± 4.9 years. Mean serum creatinine in study group was 5.2 ± 2.9 mg/dl, with mean estimated glomerular filtration rate of 23.43 ± 21.48 ml/min/1.732 m². Forty eight patients (55.81%) had diabetic retinopathy (DR); prevalence of DR was more in patients who had diabetes for > 10 years than patients who had diabetes for <6 years (P = 0.022). The most common histological class was Class IV observed in 37 (43.02. %) cases, Class III DN in 24 (27.90%) cases, Class IIa and Class IIb in 11 (12.79%) cases each and Class I DN in 3 (3.48%) cases. Higher histological class was associated with higher proteinuria, lower glomerular filtration rate (P < 0.001) and was more likely to be associated with retinopathy (P = 0.012) and hypertension (P = 0.0003) but did not correlate with duration of diabetes (P = 0.85). There was a poor correlation between retinopathy and DN. Biopsy helps to stage the renal lesions in diabetics with renal dysfunction.

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

AIMS

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

SETTINGS AND DESIGN

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

MATERIAL AND METHODS

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

STATISTICAL ANALYSIS USED

SPSS 17.

RESULTS

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

CONCLUSION

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

Regulation of podocalyxin expression in the kidney of streptozotocin-induced diabetic rats with Chinese herbs (Yishen capsule)

Background

Diabetic nephropathy is an emergent issue in China with increase in patients with type II diabetes. There are several successful Chinese herbal products for the treatment of patients with diabetic nephropathy in China. However, the mechanisms mediating the biological activity of these products are still unclear. Podocalyxin is a sialoprotein critical to maintaining integrity of filtration function of glomerulus.

Methods

By employing streptozotocin-induced diabetic rats and a Chinese herb formulation (Yishen capsule), we examined the regulation of podocalyxin expression in the kidney by Yishen capsule through immunofluorescent staining and reverse transcriptase polymerase chain reaction.

Results

After injection of STZ, there were significant increase in both blood glucose and urinary protein. Serum creatinine and BUN were also increased in rats with injection of STZ. Moreover, expression of podocalyxin in the glomerulus was gradually reduced after injection of STZ. There was also a loss of podocyte foot processes in the glomerular basement membrane. However, Yishen capsule or benazepril was able to restore the expression of podocalyxin and podocyte foot processes in the kidney. Although Yishen capsule could reduce urinary protein level, it has little effect on blood glucose level in the rats injected with STZ.

Conclusions

Yishen capsule could attenuate the loss of podocalyxin in the glomerulus of rats injected with STZ.