Is diabetic nephropathy reversible?

Machine learning techniques to predict the risk of developing diabetic nephropathy: a literature review

Purpose

Diabetes is a major public health challenge with widespread prevalence, often leading to complications such as Diabetic Nephropathy (DN)-a chronic condition that progressively impairs kidney function. In this context, it is important to evaluate if Machine learning models can exploit the inherent temporal factor in clinical data to predict the risk of developing DN faster and more accurately than current clinical models.

Methods

Three different databases were used for this literature review: Scopus, Web of Science, and PubMed. Only articles written in English and published between January 2015 and December 2022 were included.

Results

We included 11 studies, from which we discuss a number of algorithms capable of extracting knowledge from clinical data, incorporating dynamic aspects in patient assessment, and exploring their evolution over time. We also present a comparison of the different approaches, their performance, advantages, disadvantages, interpretation, and the value that the time factor can bring to a more successful prediction of diabetic nephropathy.

Conclusion

Our analysis showed that some studies ignored the temporal factor, while others partially exploited it. Greater use of the temporal aspect inherent in Electronic Health Records (EHR) data, together with the integration of omics data, could lead to the development of more reliable and powerful predictive models.

Chronic Kidney Disease Diets for Kidney Failure Prevention: Insights from the IL-11 Paradigm

Nearly every fifth adult in the United States and many older adults worldwide are affected by chronic kidney disease (CKD), which can progress to kidney failure requiring invasive kidney replacement therapy. In this review, we briefly examine the pathophysiology of CKD and discuss emerging mechanisms involving the physiological resolution of kidney injury by transforming growth factor beta 1 (TGFβ1) and interleukin-11 (IL-11), as well as the pathological consequences of IL-11 overproduction, which misguides repair processes, ultimately culminating in CKD. Taking these mechanisms into account, we offer an overview of the efficacy of plant-dominant dietary patterns in preventing and managing CKD, while also addressing their limitations in terms of restoring kidney function or preventing kidney failure. In conclusion, this paper outlines novel regeneration strategies aimed at developing a reno-regenerative diet to inhibit IL-11 and promote repair mechanisms in kidneys affected by CKD.

Screening candidate diagnostic biomarkers for diabetic kidney disease

BACKGROUND

There are big differences in treatments and prognosis between diabetic kidney disease (DKD) and non-diabetic renal disease (NDRD). However, DKD patients couldn't be diagnosed early due to lack of special biomarkers. Urine is an ideal non-invasive sample for screening DKD biomarkers. This study aims to explore DKD special biomarkers by urinary proteomics.

MATERIALS AND METHODS

According to the result of renal biopsy, 142 type 2 diabetes mellitus (T2DM) patients were divided into 2 groups: DKD (n = 83) and NDRD (n = 59). Ten patients were selected from each group to define urinary protein profiles by label-free quantitative proteomics. The candidate proteins were further verifyied by parallel reaction monitoring (PRM) methods (n = 40). Proteins which perform the same trend both in PRM and proteomics were verified by enzyme-linked immunosorbent assays (ELISA) with expanding the sample size (n = 82). The area under the receiver operating characteristic curve (AUC) was used to evaluate the accuracy of diagnostic biomarkers.

RESULTS

We identified 417 peptides in urinary proteins showing significant difference between DKD and NDRD. PRM verification identified C7, SERPINA4, IGHG1, SEMG2, PGLS, GGT1, CDH2, CDH1 was consistent with the proteomic results and p < 0.05. Three potential biomarkers for DKD, C7, SERPINA4, and gGT1, were verified by ELISA. The combinatied SERPINA4/Ucr and gGT1/Ucr (AUC = 0.758, p = 0.001) displayed higher diagnostic efficiency than C7/Ucr (AUC = 0.632, p = 0.048), SERPINA4/Ucr (AUC = 0.661, p = 0.032), and gGT1/Ucr (AUC = 0.661, p = 0.029) respectively.

CONCLUSIONS

The combined index SERPINA4/Ucr and gGT1/Ucr can be considered as candidate biomarkers for diabetic nephropathy after adjusting by urine creatinine.

Lysozyme promotes renal fibrosis through the JAK/STAT3 signal pathway in diabetic nephropathy

Introduction

Diabetic nephropathy (DN) is a leading cause of kidney failure. Lysozyme (LYZ) is an essential component of innate immunity and exhibits antibacterial properties. However, LYZ has been reported to induce nephropathy, implying a possible association between impaired renal function and lysozyme expression.

Material and methods

Bioinformatics analysis was used to predict the hub gene associated with DN, and the differential expression of the hub gene was confirmed using a mouse model. A mouse model of streptozotocin (STZ)-induced diabetic nephropathy was established to investigate the correlation between DN and LYZ expression, and the functionality of LYZ was verified through knockdown and overexpression experiments conducted in vivo. Immunohistochemistry (IHC) was utilized to assess fibrosis-related markers and cytokines, while Masson staining was performed to assess renal fibrosis. Fibroblast proliferation was assessed using the Cell Counting Kit-8 (CCK-8) assay. The role of the JAK pathway was confirmed using the JAK inhibitor AG490, and Western blot was used to investigate the underlying mechanisms.

Results

Mechanistically, 25 mM glucose promotes the expression of LYZ in fibroblastic cells, and LYZ may in turn promote the proliferation of renal interstitial fibroblasts. Western blot shows that glucose can activate STAT3 in an LYZ-dependent manner, and the JAK inhibitor AG490 can partially suppress LYZ-induced STAT3 activation. Furthermore, in vivo observations have revealed that overexpression of LYZ is associated with the senescent phenotype of renal tubular epithelial cells (RTECs).

Conclusions

Lysozyme promotes kidney fibrosis via the JAK/STAT3 signaling pathway in diabetic nephropathy, and glucose may promote fibroblast proliferation by promoting LYZ auto-secretion.

Identification of genetic variants associated with diabetic kidney disease in multiple Korean cohorts via a genome-wide association study mega-analysis

BACKGROUND

The pathogenesis of diabetic kidney disease (DKD) is complex, involving metabolic and hemodynamic factors. Although DKD has been established as a heritable disorder and several genetic studies have been conducted, the identification of unique genetic variants for DKD is limited by its multiplex classification based on the phenotypes of diabetes mellitus (DM) and chronic kidney disease (CKD). Thus, we aimed to identify the genetic variants related to DKD that differentiate it from type 2 DM and CKD.

METHODS

We conducted a large-scale genome-wide association study mega-analysis, combining Korean multi-cohorts using multinomial logistic regression. A total of 33,879 patients were classified into four groups-normal, DM without CKD, CKD without DM, and DKD-and were further analyzed to identify novel single-nucleotide polymorphisms (SNPs) associated with DKD. Additionally, fine-mapping analysis was conducted to investigate whether the variants of interest contribute to a trait. Conditional analyses adjusting for the effect of type 1 DM (T1D)-associated HLA variants were also performed to remove confounding factors of genetic association with T1D. Moreover, analysis of expression quantitative trait loci (eQTL) was performed using the Genotype-Tissue Expression project. Differentially expressed genes (DEGs) were analyzed using the Gene Expression Omnibus database (GSE30529). The significant eQTL DEGs were used to explore the predicted interaction networks using search tools for the retrieval of interacting genes and proteins.

RESULTS

We identified three novel SNPs [rs3128852 (P = 8.21×10^-25), rs117744700 (P = 8.28×10^-10), and rs28366355 (P = 2.04×10^-8)] associated with DKD. Moreover, the fine-mapping study validated the causal relationship between rs3128852 and DKD. rs3128852 is an eQTL for TRIM27 in whole blood tissues and HLA-A in adipose-subcutaneous tissues. rs28366355 is an eQTL for HLA-group genes present in most tissues.

CONCLUSIONS

We successfully identified SNPs (rs3128852, rs117744700, and rs28366355) associated with DKD and verified the causal association between rs3128852 and DKD. According to the in silico analysis, TRIM27 and HLA-A can define DKD pathophysiology and are associated with immune response and autophagy. However, further research is necessary to understand the mechanism of immunity and autophagy in the pathophysiology of DKD and to prevent and treat DKD.

Microencapsulated islet transplantation alleviates podocyte injury in diabetic nephropathy via inhibiting Notch-1 signaling

OBJECTIVE

Podocyte injury has a critical role in the pathogenesis of diabetic nephropathy (DN). Microencapsulated islet transplantation (MIT) is identified as an effective method for improving the clinical condition of DN. This study aimed to explore the role and mechanism of MIT in alleviating podocyte injury in DN.

METHODS

A mouse model of DN was constructed using streptozotocin (STZ). Mice were divided into 3 groups: the untreated diabetic nephropathy group (DN group), the microencapsulated islet transplantation-treated group (MIT group) and the control group. The mice were raised for 6 weeks posterior to islet transplantation to identify the role of MIT. Renal function and structure of glomerular filtration barrier were assessed by urine analysis, histopathological examination, and transmission electron microscopy. The expression levels of several proteins including Caspase-3, Bcl2/Bax, β-galactosidase, Ki-67, synaptopodin, WT-1, Jagged-1, Notch-1, and Hes-1 in renal tissues were identified via immunohistochemistry (IHC), immunofluorescence (IF), and western blotting techniques.

RESULTS

Compared with the DN group, the MIT group presented decreased levels of blood glucose, urinary albumin/creatinine, urea nitrogen, and serum creatinine while their body weight gradually increased. Glomerular injury in the MIT group was significantly better than that in the DN group. The MIT group indicated significantly decreased expression of Caspase-3, β-galactosidase, Bax/Bcl-2, and Ki-67 when compared with DN group, while the proportion of synaptopodin- and WT-1-positive cells was significantly increased (P < 0.05). The protein expression of Jagged-1, Notch-1, and Hes-1 in the glomerulus of the MIT group was significantly lower than that in the DN group (P < 0.05).

CONCLUSION

MIT alleviates podocyte injury induced by DN by inhibiting Notch-1 signaling. The identification of signaling pathways influencing podocyte restoration can help evaluate personalized medicine efficacy for patients treated with islet transplantation.

Interobserver reproducibility of contrast-enhanced ultrasound in diabetic nephropathy

OBJECTIVE

To investigate the interobserver reproducibility of contrast-enhanced ultrasound (CEUS) in patients with diabetic nephropathy.

METHODS

A total of 40 patients with diabetic nephropathy were enrolled in this retrospective study. We measured peak intensity (PEAK), time-to-peak (TP), area under the curve (AUC) and mean transit time (MTT) of renal CEUS in each patient. Each parameter was performed by two independent observers. The interobserver reproducibility was assessed using intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs) and Bland-Altman plots by mean difference with 95% limits of agreement (LOAs).

RESULTS

The parameters of the left and right kidneys showed moderate or good reliability. The best was the left kidney AUC parameters (ICC,0.945),with a 95% CI of 0.896-0.971.The Bland-Altman plots showed that the mean differences between the right renal parameters (PEAK, TP, AUC and MTT) obtained between the observers 1 and 2 were -6.63%,2.54%,-11.30%,-2.22%, and the 95% LOAs are -30.78 to 17.52%, -30.15 to 35.23%, -43.95 to 21.35%, -44.50 to 40.06%. While the left ones were -2.89%, 0.32%, -8.26%, 1.25% , and the 95% LOAs were -38.50 to 32.72%, -31.98 to 32.62%, -57.89 to 41.37%, -37.21 to 39.71%, respectively.

CONCLUSION

Quantitative CEUS can show good interobserver reproducibility, which is better for the right kidney. It seems necessary to establish standardized techniques for obtaining contrast-enhanced quantitative analysis of renal blood perfusion.

ADVANCES IN KNOWLEDGE

Quantitative assessment of renal perfusion by CEUS in patients with diabetic nephropathy provides diagnostic information. Furthermore, renal perfusion assessment in patients with diabetic nephropathy using CEUS has good reproducibility.

Biomarkers for Detecting Kidney Dysfunction in Type-2 Diabetics and Diabetic Nephropathy Subjects: A Case-Control Study to Identify Potential Biomarkers of DN to Stratify Risk of Progression in T2D Patients

INTRODUCTION

Currently there are no biomarkers that are predictive of when patients with type-2 diabetes (T2D) will progress to more serious kidney disease i.e., diabetic nephropathy (DN). Biomarkers that could identify patients at risk of progression would allow earlier, more aggressive treatment intervention and management, reducing patient morbidity and mortality.

MATERIALS AND METHODS

Study participants (N=88; control n=26; T2D n=32; DN n=30) were recruited from the renal unit at Antrim Area Hospital, Antrim, UK; Whiteabbey Hospital Diabetic Clinic, Newtownabbey, UK; Ulster University (UU), Belfast, UK; and the University of the Third Age (U3A), Belfast, UK; between 2019 and 2020. Venous blood and urine were collected with a detailed clinical history for each study participant.

RESULTS

In total, 13/25 (52.0%) biomarkers measured in urine and 25/34 (73.5%) biomarkers measured in serum were identified as significantly different between control, T2D and DN participants. DN patients, were older, smoked more, had higher systolic blood pressure and higher serum creatinine levels and lower eGFR function. Serum biomarkers significantly inversely correlated with eGFR.

CONCLUSION

This pilot-study identified several serum biomarkers that could be used to predict progression of T2D to more serious kidney disease: namely, midkine, sTNFR1 and 2, H-FABP and Cystatin C. Our results warrant confirmation in a longitudinal study using a larger patient cohort.

Effects of High Glucose and Lipotoxicity on Diabetic Podocytes

Glomerular podocytes are highly differentiated cells that cover glomerular capillaries from the outside and have a characteristic morphology with numerous foot processes. The formation of slit membranes between the foot processes serves as a final filtration barrier for urine filtration from the blood. Podocyte damage causes disruption of the slit membrane, subsequent proteinuria and finally glomerulosclerosis, which is a common pathway in various types of chronic kidney disease (CKD). In recent years, there has been an increase in diabetes, due to rapid lifestyle changes, which is the main cause of CKD. Therefore, understanding the effect of diabetic status on podocytes is of great importance to establish a strategy for preventing CKD progression. In this review, we summarize altered glucose and lipid metabolism in diabetic podocytes and also discuss the reversibility of the changes in podocyte phenotype.

Calcium oxalate crystal deposition in the kidney: identification, causes and consequences

Calcium oxalate (CaOx) crystal deposition within the tubules is often a perplexing finding on renal biopsy of both native and transplanted kidneys. Understanding the underlying causes may help diagnosis and future management. The most frequent cause of CaOx crystal deposition within the kidney is hyperoxaluria. When this is seen in native kidney biopsy, primary hyperoxaluria must be considered and investigated further with biochemical and genetic tests. Secondary hyperoxaluria, for example due to enteric hyperoxaluria following bariatric surgery, ingested ethylene glycol or vitamin C overdose may also cause CaOx deposition in native kidneys. CaOx deposition is a frequent finding in renal transplant biopsy, often as a consequence of acute tubular necrosis and is associated with poorer long-term graft outcomes. CaOx crystal deposition in the renal transplant may also be secondary to any of the causes associated with this phenotype in the native kidney. The pathophysiology underlying CaOx deposition is complex but this histological phenotype may indicate serious underlying pathology and should always warrant further investigation.

Targeting the progression of chronic kidney disease

Chronic kidney disease (CKD) is a devastating condition that is reaching epidemic levels owing to the increasing prevalence of diabetes mellitus, hypertension and obesity, as well as ageing of the population. Regardless of the underlying aetiology, CKD is slowly progressive and leads to irreversible nephron loss, end-stage renal disease and/or premature death. Factors that contribute to CKD progression include parenchymal cell loss, chronic inflammation, fibrosis and reduced regenerative capacity of the kidney. Current therapies have limited effectiveness and only delay disease progression, underscoring the need to develop novel therapeutic approaches to either stop or reverse progression. Preclinical studies have identified several approaches that reduce fibrosis in experimental models, including targeting cytokines, transcription factors, developmental and signalling pathways and epigenetic modulators, particularly microRNAs. Some of these nephroprotective strategies are now being tested in clinical trials. Lessons learned from the failure of clinical studies of transforming growth factor β1 (TGFβ1) blockade underscore the need for alternative approaches to CKD therapy, as strategies that target a single pathogenic process may result in unexpected negative effects on simultaneously occurring processes. Additional promising avenues include preventing tubular cell injury and anti-fibrotic therapies that target activated myofibroblasts, the main collagen-producing cells.

Progression of diabetic nephropathy after successful pancreas transplantation alone: a case report

Pancreas transplantation is the only method that can nearly cure insulin-dependent diabetes mellitus. However, the effect of pancreas transplantation on patients with diabetic nephropathy has recently been considered controversial. In this report, we present a case of abrupt aggravation of proteinuria after successful pancreas transplantation alone without evidence of calcineurin inhibitor (CNI) toxicity. A 22-year-old female patient with type I diabetes mellitus underwent pancreas transplantation alone. The patient already had retinopathy and mild proteinuria, which in this case, may mean diabetic nephropathy. Her glucose levels were managed within the normal range after successful pancreas transplantation. However, the amount of proteinuria fluctuated. Kidney needle biopsy was performed owing to severe elevation of proteinuria, 2 years after the transplantation. Electron microscopy revealed diabetic glomerulosclerosis without evidence of CNI toxicity. This case indicates that diabetic nephropathy can be aggravated after pancreas transplantation, despite well-managed glucose levels and absence of CNI toxicity.

CKD in diabetes: diabetic kidney disease versus nondiabetic kidney disease

The increasing global prevalence of type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) has prompted research efforts to tackle the growing epidemic of diabetic kidney disease (DKD; also known as diabetic nephropathy). The limited success of much of this research might in part be due to the fact that not all patients diagnosed with DKD have renal dysfunction as a consequence of their diabetes mellitus. Patients who present with CKD and diabetes mellitus (type 1 or type 2) can have true DKD (wherein CKD is a direct consequence of their diabetes status), nondiabetic kidney disease (NDKD) coincident with diabetes mellitus, or a combination of both DKD and NDKD. Preclinical studies using models that more accurately mimic these three entities might improve the ability of animal models to predict clinical trial outcomes. Moreover, improved insights into the pathomechanisms that are shared by these entities - including sodium-glucose cotransporter 2 (SGLT2) and renin-angiotensin system-driven glomerular hyperfiltration and tubular hyper-reabsorption - as well as those that are unique to individual entities might lead to the identification of new treatment targets. Acknowledging that the clinical entity of CKD plus diabetes mellitus encompasses NDKD as well as DKD could help solve some of the urgent unmet medical needs of patients affected by these conditions.

Triptolide Attenuates Renal Tubular Epithelial-mesenchymal Transition Via the MiR-188-5p-mediated PI3K/AKT Pathway in Diabetic Kidney Disease

Triptolide possesses the trait of renal protection. Epithelial-mesenchymal transition (EMT) is closely linked to the pathogenesis of diabetic kidney disease (DKD). MicroRNAs have recently emerged as critical regulators of DKD. However, it is poorly understood whether triptolide alleviates renal EMT by regulating microRNAs in DKD. In this study, we found that triptolide decreased albuminuria, improved the renal structure and reduced renal EMT in rats with DKD. Furthermore, activation of the PI3K/AKT signaling pathway was increased in diabetic rats, which was partly reversed by triptolide. Triptolide also alleviated glucose-induced EMT in HK-2 cells in vitro. PI3K/AKT signaling pathway activation was reduced after triptolide treatment. Moreover, triptolide decreased the increase in miR-188-5p expression stimulated by high glucose levels in HK-2 cells. miR-188-5p inhibited PTEN expression by directly interacting with the PTEN 3'-untranslated region. Additionally, downregulation of miR-188-5p, which imitates the effects of triptolide, attenuated the activation of the PI3K/AKT pathway and HG-induced EMT, whereas miR-188-5p overexpression reversed the effects of triptolide on the PI3K/AKT pathway and EMT. In conclusion, we demonstrated that triptolide ameliorates renal EMT via the PI3K/AKT signaling pathway through the interaction between miR-188-5p and PTEN, indicating that miR-188-5p may be a therapeutic target of triptolide in DKD.

Reversibility of diabetes mellitus: Narrative review of the evidence

The global disease burden of diabetes mellitus is high. It is well-established that prediabetes is reversible but it is unclear whether diabetes is reversible once it has been diagnosed. The objective of this narrative review is to review the evidence of reversibility of diabetes mellitus and stimulate interest in prolonged remission as a treatment target. The current evidence for bariatric surgery is stronger than intensive medical management and the evidence is stronger for type 2 diabetes patients compared with type 1 diabetes patients. It is also unclear whether non obese diabetes patients would benefit from such interventions and the duration of diabetes before diabetes become irreversible. Further research is needed in this area especially with regards to the subgroup of diabetes patient who will benefit from these interventions and the long term safety and efficacy remains unknown especially with intensive medical management.

Inhibition of SREBP With Fatostatin Does Not Attenuate Early Diabetic Nephropathy in Male Mice

Sterol regulatory element binding protein (SREBP) is an important potential mediator of kidney fibrosis and is known to be upregulated in diabetic nephropathy. We evaluated the effectiveness of SREBP inhibition as treatment of diabetic nephropathy. Type 1 diabetes was induced in uninephrectomized male CD1 mice with streptozotocin. The mice were treated with the SREBP inhibitor fatostatin for 12 weeks. At the endpoint, kidney function and pathologic findings were assessed. Fatostatin inhibited the increase of both isoforms of SREBP (types 1 and 2) in diabetic kidneys. Treatment attenuated basement membrane thickening but did not improve hyperfiltration, albuminuria, or kidney fibrosis in diabetic mice. The treatment of nondiabetic mice with fatostatin led to hyperfiltration and increased the glomerular volume to levels seen in diabetic mice. This was associated with increased renal inflammation and a trend toward increased renal fibrosis. Both in vivo and in cultured renal proximal tubular epithelial cells, fatostatin increased the expression of the proinflammatory cytokine monocyte chemoattractant protein-1. Thus, SREBP inhibition with fatostatin not only is ineffective in preventing diabetic nephropathy but also leads to kidney injury in nondiabetic mice. Further research on the efficacy of other SREBP inhibitors and the specific roles of SREBP-1 and SREBP-2 in the treatment and pathogenesis of diabetic nephropathy is needed.

A new pathological scoring system by the Japanese classification to predict renal outcome in diabetic nephropathy

Background and objectives

The impact of the newly proposed pathological classification by the Japan Renal Pathology Society (JRPS) on renal outcome is unclear. So we evaluated that impact and created a new pathological scoring to predict outcome using this classification.

Design, setting, participants, & measurements

A multicenter cohort of 493 biopsy-proven Japanese patients with diabetic nephropathy (DN) were analyzed. The association between each pathological factor—Tervaert’ and JRPS classifications—and renal outcome (dialysis initiation or 50% eGFR decline) was estimated by adjusted Cox regression. The overall pathological risk score (J-score) was calculated, whereupon its predictive ability for 10-year risk of renal outcome was evaluated.

Results

The J-scores of diffuse lesion classes 2 or 3, GBM doubling class 3, presence of mesangiolysis, polar vasculosis, and arteriolar hyalinosis were, respectively, 1, 2, 4, 1, and 2. The scores of IFTA classes 1, 2, and 3 were, respectively, 3, 4, and 4, and those of interstitial inflammation classes 1, 2, and 3 were 5, 5, and 4 (J-score range, 0–19). Renal survival curves, when dividing into four J-score grades (0–5, 6–10, 11–15, and 16–19), were significantly different from each other (p<0.01, log-rank test). After adjusting clinical factors, the J-score was a significant predictor of renal outcome. Ability to predict 10-year renal outcome was improved when the J-score was added to the basic model: c-statistics from 0.661 to 0.685; category-free net reclassification improvement, 0.154 (-0.040, 0.349, p = 0.12); and integrated discrimination improvement, 0.015 (0.003, 0.028, p = 0.02).

Conclusions

Mesangiolysis, polar vasculosis, and doubling of GBM—features of the JRPS system—were significantly associated with renal outcome. Prediction of DN patients’ renal outcome was better with the J-score than without it.

Effects of glycaemic management on diabetic kidney disease

Hyperglycaemia contributes to the onset and progression of diabetic kidney disease (DKD). Observational studies have not consistently demonstrated a glucose threshold, in terms of HbA1c levels, for the onset of DKD. Tight glucose control has clearly been shown to reduce the incidence of micro- or macroalbuminuria. However, evidence is now also emerging to suggest that intensive glucose control can slow glomerular filtration rate loss and possibly progression to end stage kidney disease. Achieving tight glucose control needs to be balanced against the increasing appreciation that glucose targets for the prevention of diabetes related complications need be individualised for each patient. Recently, empagliflozin which is an oral glucose lowering agent of the sodium glucose cotransporter-2 inhibitor class has been shown to have renal protective effects. However, the magnitude of empagliflozin’s reno-protective properties are over and above that expected from its glucose lowering effects and most likely largely result from mechanisms involving alterations in intra-renal haemodynamics. Liraglutide and semaglutide, both injectable glucose lowering agents which are analogues of human glucagon like peptide-1 have also been shown to reduce progression to macroalbuminuria through mechanisms that remain to be fully elucidated. Here we review the evidence from observational and interventional studies that link good glucose control with improved renal outcomes. We also briefly review the potential reno-protective effects of newer glucose lowering agents.

Accumulation of worn-out GBM material substantially contributes to mesangial matrix expansion in diabetic nephropathy

Thickening of the glomerular basement membrane (GBM) and expansion of the mesangial matrix are hallmarks of diabetic nephropathy (DN), generally considered to emerge from different sites of overproduction: GBM components from podocytes and mesangial matrix from mesangial cells. Reevaluation of 918 biopsies with DN revealed strong evidence that these mechanisms are connected to each other, wherein excess GBM components fail to undergo degradation and are deposited in the mesangium. These data do not exclude that mesangial cells also synthesize components that contribute to the accumulation of matrix in the mesangium. Light, electron microscopic, immunofluorescence, and in situ hybridization studies clearly show that the thickening of the GBM is due not only to overproduction of components of the mature GBM (α3 and α5 chains of collagen IV and agrin) by podocytes but also to resumed increased synthesis of the α1 chain of collagen IV and of perlecan by endothelial cells usually seen during embryonic development. We hypothesize that these abnormal production mechanisms are caused by different processes: overproduction of mature GBM-components by the diabetic milieu and regression of endothelial cells to an embryonic production mode by decreased availability of mediators from podocytes.

Sustained kidney biochemical derangement in treated experimental diabetes: a clue to metabolic memory

The occurrence of biochemical alterations that last for a long period of time in diabetic individuals even after adequate handling of glycemia is an intriguing phenomenon named metabolic memory. In this study, we show that a kidney pathway is gradually altered during the course of diabetes and remains persistently changed after late glycemic control in streptozotocin-induced diabetic rats. This pathway comprises an early decline of uric acid clearance and pAMPK expression followed by fumarate accumulation, increased TGF-β expression, reduced PGC-1α expression, and downregulation of methylation and hydroxymethylation of mitochondrial DNA. The sustained decrease of uric acid clearance in treated diabetes may support the prolonged kidney biochemical alterations observed after tight glycemic control, and this regulation is likely mediated by the sustained decrease of AMPK activity and the induction of inflammation. This manuscript proposes the first consideration of the possible role of hyperuricemia and the underlying biochemical changes as part of metabolic memory in diabetic nephropathy development after glycemic control.

Histological reversibility of diabetic nephropathy after kidney transplantation from diabetic donor to non-diabetic recipient

AIM

Given the recent increase in the prevalence of diabetes mellitus, it is not uncommon for kidney transplantation donors to have diabetes. We perform kidney transplantation in our hospital if the diabetic donors are receiving oral hypoglycaemic agents, but not insulin, and their haemoglobin A1C (HbA1C) is below 6.5%. There are few reports about histological changes to diabetic nephropathy after transplantation of kidney grafts from donors with diabetes mellitus to non-diabetic recipients. Therefore, we studied the histological diabetic changes in grafts from diabetic donors at protocol biopsies (1 hour, 1 month, 1 year), and evaluated whether they improved under the recipient's good glycaemic control.

METHODS

Three cases of kidney transplantation from donors with diabetes mellitus to non-diabetic recipients were selected. We used a pathological classification established by the Renal Pathology Society for evaluating histological improvements in diabetic nephropathy.

RESULTS

The results revealed that early diabetic changes found at the 1-hour and 1-month protocol biopsies were reversed and improved at the 1-year biopsy.

CONCLUSION

We concluded that early diabetic changes in grafts from diabetic donors may improve if the graft recipient has good glycaemic control after kidney transplantation.

Chinese medicines in the treatment of experimental diabetic nephropathy

Diabetic nephropathy (DN) is a severe micro vascular complication accompanying diabetes mellitus that affects millions of people worldwide. End-stage renal disease occurs in nearly half of all DN patients, resulting in large medical costs and lost productivity. The course of DN progression is complicated, and effective and safe therapeutic strategies are desired. While the complex nature of DN renders medicines with a single therapeutic target less efficacious, Chinese medicine, with its holistic view targeting the whole system of the patient, has exhibited efficacy for DN management. This review aims to describe the experimental evidence for Chinese medicines in DN management, with an emphasis on the underlying mechanisms, and to discuss the combined use of herbs and drugs in DN treatment.

Finerenone : third-generation mineralocorticoid receptor antagonist for the treatment of heart failure and diabetic kidney disease

INTRODUCTION

The mineralocorticoid receptor antagonists (MRAs) spironolactone and eplerenone reduce the risk of hospitalizations and mortality in patients with heart failure (HF) with reduced ejection fraction (HFrEF), and attenuate progression of diabetic kidney disease. However, their use is limited by the fear of inducing hyperkalemia, especially in patients with renal dysfunction. Finerenone is a novel nonsteroidal MRA, with higher selectivity toward the mineralocorticoid receptor (MR) compared to spironolactone and stronger MR-binding affinity than eplerenone.

AREAS COVERED

This paper discusses the chemistry, pharmacokinetics, clinical efficacy and safety of finerenone.

EXPERT OPINION

The selectivity and greater binding affinity of finerenone to the MR may reduce the risk of hyperkalemia and renal dysfunction and thereby overcome the reluctance to start and uptitrate MRAs in patients with HF and diabetic kidney disease. Studies conducted in patients with HFrEF and moderate chronic kidney disease and diabetic kidney disease, showed promising results. Phase III trials will have to show whether finerenone might become the third-generation MRA for the treatment of HF and diabetic kidney disease.