Clinicopathological study of nondiabetic renal disease in type 2 diabetic patients: A single center experience from India

Association between a high triglyceride-glucose index and chronic kidney disease in adult patients with latent autoimmune diabetes

BACKGROUND

Insulin resistance (IR) is one of the risk factors for chronic kidney disease (CKD) and diabetes. The triglyceride-glucose (TyG) index is considered a reliable alternative marker of IR. We investigated the correlation between the TyG index and the severity of CKD in patients with latent autoimmune diabetes in adults (LADA).

METHODS

This cross-sectional study included 288 patients with LADA in the department of endocrinology at our hospital between January 2018 and January 2022. The TyG index was calculated as Ln [TG (mg/dl) × fasting blood glucose (FBG) (mg/dl) / 2]. All individuals were divided into either a LADA + CKD group or a LADA + non-CKD group according to the presence or absence of CKD. A correlation analysis, logistic regression analysis and receiver operating characteristics curve analysis were performed.

RESULTS

A total of 130 (45.1%) participants were identified as having CKD. Compared with the non-CKD group, the CKD group had a longer disease duration and a higher proportion of smokers; patients were more likely to have hypertension and higher serum creatinine, triglyceride, cholesterol, low-density lipoprotein cholesterol, FBG, uric acid estimated glomerular filtration rates (eGFR) and TyG levels as well as lower high-density lipoprotein cholesterol levels (all P < 0.05). The positive relationship between the TyG index and the urinary albumin/creatinine ratio was significant (r = 0.249, P = 0.010). There was also a significant correlation between the TyG index and the eGFR (r = - 0.211, P = 0.034) after adjusting for confounding factors. The area-under-the-curve value of the TyG index was 0.708 (95% confidence interval: 0.61-0.81, P < 0.001).

CONCLUSIONS

The TyG index is significantly associated with the severity of CKD in patients with LADA. This conclusion supports the clinical application of the TyG index for the assessment of kidney disease in patients with LADA.

The Complement Pathway: New Insights into Immunometabolic Signaling in Diabetic Kidney Disease

Significance: The metabolic disorder, diabetes mellitus, results in microvascular complications, including diabetic kidney disease (DKD), which is partly believe to involve disrupted energy generation in the kidney, leading to injury that is characterized by inflammation and fibrosis. An increasing body of evidence indicates that the innate immune complement system is involved in the pathogenesis of DKD; however, the precise mechanisms remain unclear. Recent Advances: Complement, traditionally thought of as the prime line of defense against microbial intrusion, has recently been recognized to regulate immunometabolism. Studies have shown that the complement activation products, Complement C5a and C3a, which are potent pro-inflammatory mediators, can mediate an array of metabolic responses in the kidney in the diabetic setting, including altered fuel utilization, disrupted mitochondrial respiratory function, and reactive oxygen species generation. In diabetes, the lectin pathway is activated via autoreactivity toward altered self-surfaces known as danger-associated molecular patterns, or via sensing altered carbohydrate and acetylation signatures. In addition, endogenous complement inhibitors can be glycated, whereas diet-derived glycated proteins can themselves promote complement activation, worsening DKD, and lending support for environmental influences as an additional avenue for propagating complement-induced inflammation and kidney injury. Critical Issues: Recent evidence indicates that conventional renoprotective agents used in DKD do not target the complement, leaving this web of inflammatory stimuli intact. Future Directions: Future studies should focus on the development of novel pharmacological agents that target the complement pathway to alleviate inflammation, oxidative stress, and kidney fibrosis, thereby reducing the burden of microvascular diseases in diabetes. Antioxid. Redox Signal. 37, 781-801.

The olive constituent oleuropein exerts nephritic protective effects on diabetic nephropathy in db/db mice

BACKGROUND

Oleuropein, the most prevalent polyphenol in olives, exerts many positive impacts on human health, including counteracting cancer. However, the effect of oleuropein on diabetic nephropathy (DN) progression remains elusive.

METHODS

A total of three groups of mice were used in our study. Two groups of db/db mice fed with or without oleuropein. A group of wide-type mice fed with normal diet was used as normal control. After ten weeks of treatment, the body weight, biochemical parameters, oxidative stress markers, inflammatory cytokines levels, and kidney injury status were measured.

RESULTS

Our results demonstrated that oral administration of oleuropein reduced body weight, alleviated kidney injury, and decreased oxidative stress and inflammatory response in db/db mice. The oleuropein inhibited cell apoptosis via regulation of MAPK signalling pathways and its downstream targets Bax, caspase-3, and Bcl-2 expression.

CONCLUSION

Oleuropein may server as a favourable additional agent for the treatment of patients with DN.

Altered Renal Pathology in an Autoimmune Disease Mouse Model After Induction of Diabetes Mellitus

Diabetes mellitus (DM) is a predisposing factor for renal disorder progression and is referred to as diabetic kidney disease (DKD). However, there are no reports of DKD with an underlying autoimmune disorder. In this study, we compared the pathophysiological changes caused by DM induction after streptozotocin (STZ) injection in comparison with that in a control group receiving citrate buffer (CB) in the autoimmune disease model mice “BXSB/MpJ-Yaa” (Yaa) and the wild-type strain BXSB/MpJ. Both strains showed hyperglycemia after 12 weeks of STZ injection. Interestingly, the Yaa group developed membranous and proliferative glomerulonephritis, which tended to be milder glomerular lesions in the STZ group than in the CB group, as indicated by a decreased mesangial area and ameliorated albuminuria. Statistically, the indices for hyperglycemia and autoimmune abnormalities were negatively and positively correlated with the histopathological parameters for mesangial matrix production and glomerular proliferative lesions, respectively. STZ treatment induced renal tubular anisonucleosis and dilations in both strains, and they were more severe in Yaa. Significantly decreased cellular infiltration was observed in the Yaa group compared to the CB group. Thus, in DKD related to autoimmune nephritis, hyperglycemia modifies its pathology by decreasing the mesangial area and interstitial inflammation and aggravating renal tubular injury.

Prevalence of Nondiabetic Renal Disease in Patients with Type 2 Diabetes Mellitus with Clinicopathological Correlation: A Study from a Tertiary Care Center of Assam, India

Diabetes mellitus is the most common cause of chronic kidney disease worldwide. The prevalence of nondiabetic renal disease (NDRD) among patients with type 2 diabetes mellitus (T2DM) varies widely. This study aimed to evaluate the renal biopsies performed on type 2 diabetic patients for suspicion of NDRD and to correlate clinicopathological findings. All T2DM patients aged > 18 years were included in this study, who had renal biopsy performed for the following reasons: recent-onset nephrotic syndrome, unexplained rapid deterioration of renal function, proteinuria not accompanied by retinopathy, and unexplained hematuria. Renal biopsy was analyzed by light microscopy and immunofluorescence. Based on biopsy findings, the patients were grouped into three: (i) isolated NDRD, (ii) NDRD ± diabetic nephropathy (DN), and (iii) isolated DN. A total of 140 patients were enrolled in this study. Recent-onset nephrotic syndrome was the most common indication for biopsy, followed by the presence of active urine sediment. Forty-two percent of the patients had isolated DN, while NDRD was seen in 34% and DN ± NDRD in 24%. Focal segmental glomerulosclerosis (FSGS) and IgA nephropathy were the most common causes of isolated NDRD, while chronic tubulointerstitial nephritis (CTIN) was common in NDRD plus DN. Short duration of diabetes, absence of diabetic retinopathy, and lower glycated hemoglobin were predictive of NDRD. NDRD was seen in 58% of the patients with atypical presentations. FSGS and CTIN were common in NDRD diseases. Judicious use of biopsy in diabetic patients with atypical presentation may help in the diagnosis of NDRD.

Insights into the Role of Renal Biopsy in Patients with T2DM: A Literature Review of Global Renal Biopsy Results

INTRODUCTION

Renal biopsy performed in patients with type 2 diabetes mellitus (T2DM) for atypical or suspected diabetic kidney disease (DKD) reveals one of three possibilities: diabetic nephropathy (DN, pathological diagnosis of DKD), nondiabetic kidney disease (NDKD) and DN plus NDKD (mixed form). NDKD (including the mixed form) is increasingly being recognized worldwide. With the emerging concept of DKD and the complexity of routine application of renal biopsy, the identification of "clinical indicators" to differentiate DKD from NDKD has been an area of active research.

METHODS

The PubMed database was searched for relevant articles mainly according to the keyword search method. We reviewed prevalence of the three types of DKD and different pathological lesions of NDKD. We also reviewed the clinical indicators used to identify DKD and NDKD.

RESULTS

The literature search identified 40 studies (5304 data) worldwide between 1977 and 2019 that looked at global renal biopsy and pathological NDKD lesions. The overall prevalence rate of DN, NDKD and DN plus NDKD is reported to be 41.3, 40.6 and 18.1%, respectively. In Asia, Africa (specifically Morocco and Tunisia) and Europe, the most common isolated NDKD pathological type is membranous nephropathy, representing 24.1, 15.1 and 22.6% of cases, respectively. In contrast, focal segmental glomerulosclerosis is reported to be the primary pathological type in North America (specifically the USA) and Oceania (specifically New Zealand), representing 22% and 63.9% of cases, respectively. Tubulointerstitial disease accounts for a high rate in the mixed group (21.7%), with acute interstitial nephritis being the most prevalent (9.3%), followed by acute tubular necrosis (9.0%). Regarding clinical indicators to differentiate DKD from NDKD, a total of 14 indicators were identified included in 42 studies. Among these, the most commonly studied indicators included diabetic retinopathy, duration of diabetes, proteinuria and hematuria. Regrettably, indicators with high sensitivity and specificity have not yet been identified.

CONCLUSION

To date, renal biopsy is still the gold standard to diagnose diabetes complicated with renal disease, especially when T2DM patients present atypical DKD symptoms (e.g. absence of diabetic retinopathy, shorter duration of diabetes, microscopic hematuria, sub-nephrotic range proteinuria, lower glycated hemoglobin, lower fasting blood glucose). We conclude that renal biopsy as early as possible is of great significance to enable personalized treatment to T2DM patients.

Diagnostic Performance of Retinopathy in the Detection of Diabetic Nephropathy in Type 2 Diabetes: A Systematic Review and Meta-Analysis of 45 Studies

AIMS

To conduct an evidence-based evaluation of diabetic retinopathy (DR) for the diagnosis of diabetic nephropathy (DN) in type 2 diabetics with kidney disease.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Library from inception to June 27, 2018, including the reference lists of identified primary studies. A study was included if it (1) used DR as a diagnostic test for DN; and (2) used histological evaluation of renal tissues as the reference standard.

RESULTS

The analysis included 45 studies (4,561 patients). A bivariate analysis yielded a sensitivity of 0.67 (95% CI 0.61-0.74) and a specificity of 0.78 (95% CI 0.73-0.82). The summary receiver operating characteristic curve analysis provided an area under the curve (AUC) of 0.79 (95% CI 0.76-0.83). In a setting of 41% prevalence of DN, the probability of DN would be 68% if the test of DR was positive, and the probability of DN would be 23% if it was negative. In addition, although the mean specificity of proliferative DR for the detection of DN was 0.99 (95% CI 0.45-1.00), the mean sensitivity was 0.34 (95% CI 0.24-0.44), and the AUC was 0.58 (95% CI 0.53-0.62).

CONCLUSIONS

DR is helpful in diagnosing DN in persons with type 2 diabetes and kidney disease, but the severity of DR may not parallel the presence of DN.

Meta-Analysis of Diagnostic Accuracy of Retinopathy for the Detection of Diabetic Kidney Disease in Adults With Type 2 Diabetes

OBJECTIVES

The study aimed to explore whether diabetic retinopathy (DR) could distinguish diabetic kidney disease (DKD) from nondiabetic renal diseases (NDRDs) in patients with type 2 diabetes mellitus and renal disease.

METHODS

We searched PubMed, Embase, Cochrane, MEDLINE and China National Knowledge Internet for articles that enrolled patients with DKD and NDRD. The results were summarized as sensitivity, specificity and the area under the curve of summary receiver operating characteristic curve with their 95% confidence intervals (CIs).

RESULTS

A total of 51 studies that included 4,990 participants were collected for evaluation. The overall pooled sensitivity, specificity and area under the curve with their 95% CIs were 0.67 (95% CI 0.61, 0.73), 0.77 (95% CI 0.72, 0.81) and 0.78 (95% CI 0.75 to 0.82), respectively. If the test for DR is negative, the probability of DKD would decrease to 10%, but if the test for DR is positive, the probability would increase only to 42%. In addition, although the mean specificity of proliferative DR for detection of DKD was 0.98 (95% CI 0.92 to 1.00), the mean sensitivity was 0.25 (95% CI 0.16, 0.35).

CONCLUSIONS

DR may lack adequate evidence either to verify DKD or to exclude NDRD, and the severity of DR may not parallel the presence of DKD.