Diabetic Proteinuria Revisited: Updated Physiologic Perspectives

Albumin-seeking NIR dyes for high-sensitive imaging of glomerular filtration barrier breakdown

The kidney, vital for metabolic balance, faces risks of severe diseases if dysfunctional. The glomerular filtration barrier (GFB), crucial for blood filtration, disrupts in conditions like diabetic nephropathy or nephritides, resulting in proteinuria or even renal failure. Monitoring GFB integrity is essential for early diagnosis or prognostic monitoring. However, current methods lack effective contrast agents for precise, non-invasive GFB imaging. As near-infrared-II (NIR-II) imaging offers promising imaging quality due to its deep tissue penetration and high resolution/contrast while albumin servers as an efficient biomarker for GFB disruption, developing NIR-II dyes with inherent albumin-targeting moiety, will provide real-time imaging of GFB disruption. Here, we adopt albumin-seeking cyanine dye to high-resolution image endogenous albumin in mouse models, facilitating detecting even mild disruptions with trace proteinuria. Notably, our strategy can determine albuminuria by real time imaging without the need to collect urine. Albumin-seeking dyes also enable fast and accurate quantitative measurement of microalbuminuria from patients. These dyes could revolutionize diagnostics, offering rapid, sensitive in vivo imaging of microalbuminuria and diverse clinical applications.

Treatment strategies to reduce cardiovascular risk in persons with chronic kidney disease and Type 2 diabetes

Chronic kidney disease (CKD) is a prevalent and progressive condition associated with significant mortality and morbidity. Diabetes is a common cause of CKD, and both diabetes and CKD increase the risk of cardiovascular disease (CVD), the leading cause of death in individuals with CKD. This review will discuss the importance of early detection of CKD and prompt pharmacological intervention to slow CKD progression and delay the development of CVD for improving outcomes. Early CKD is often asymptomatic, and diagnosis usually requires laboratory testing. The combination of estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) measurements is used to diagnose and determine CKD severity. Guidelines recommend at least annual screening for CKD in at-risk individuals. While eGFR testing rates are consistently high, rates of UACR testing remain low. This results in underdiagnosis and undertreatment of CKD, leaving many individuals at risk of CKD progression and CVD. UACR testing is an actionable component of the CKD definition. A four-pillar treatment approach for slowing the progression of diabetic kidney disease is suggested, comprising a renin-angiotensin-system (RAS) inhibitor, a sodium-glucose cotransporter 2 inhibitor, a glucagon-like peptide 1 receptor agonist, and the nonsteroidal mineralocorticoid receptor antagonist finerenone. The combination of these agents provides a greater cardiorenal risk reduction compared with RAS inhibitors alone. Early detection of CKD and prompt intervention with guideline-directed medical therapy are crucial for reducing CVD risk in individuals with CKD and diabetes. Evidence from ongoing studies will advance our understanding of optimal therapy in this population.

Is There a Diagnostic and Prognostic Role for Anti-Nephrin Autoantibodies in Diabetic Nephropathy?

Diabetic nephropathy (DN) is one of the key causes of end-stage kidney disease worldwide, especially in developed countries. The classic pathogenic development of DN is characterized by microalbuminuria which would progress to nephrotic-range proteinuria and loss of kidney function. The degree of albuminuria is considered an independent risk factor for all-cause mortality in patients with DN. It is now well established that albuminuria stems from disruptions in podocyte structure and function. Podocytes play a major role in the glomerular filtration barrier. The nephrin protein has been identified as a core component of the slit diaphragm in podocytes, and as such, the downregulation of nephrin expression has been described well in various proteinuric glomerulopathies, including DN. Previous studies have shown that the presence of urinary nephrin potentially signifies an early marker of podocyte injury in DN. More recently, there have been increasing bodies of evidence which suggest that circulating autoantibodies targeting nephrin contributes to the pathogenesis of podocytopathies. However, the functional significance of these circulating autoantibodies in patients with DN is not well understood. In this review, we aim to evaluate the significance of nephrin dysregulation in the pathogenesis of DN based on the current available literature and provide an overview on the application of circulating anti-nephrin autoantibodies in relation to its diagnostic as well as prognostic role in podocytopathies, including DN.

Megalin: A Sidekick or Nemesis of the Kidney?

Megalin is an endocytic receptor in the proximal tubules that reabsorbs filtered proteins in the kidneys. Recycling of megalin after endocytosis and its expression on the apical plasma membrane of the proximal tubule are critical for its function. The expression of megalin in the kidney undergoes dynamic changes under physiologic and pathophysiologic conditions. Receptors and various effector signaling components regulate megalin expression and, potentially, function. Genetic manipulation and rare mutations in megalin suggest that a lack of or deficiency in megalin expression/function promotes tubular proteinuria and albuminuria. However, the role of megalin in kidney diseases associated with obesity, diabetes, hypertension, and nephrotoxicity remains unclear. To address these questions, animal and human studies have indicated megalin as a protective, injurious, and potentially urinary marker of nephropathy. This article reviews the literature on the regulation of megalin expression and the role of megalin in the pathophysiology of the kidney under experimental and clinical conditions. Moreover, this review articulates the need for studies that can clarify whether megalin can serve as a therapeutic target, in one way or the other, to treat kidney disease.

Near-infrared microscopy reveals diabetic nephropathy in ob/ob mice

Diabetic nephropathy (DN) is a major cause of global kidney failure. While histological kidney biopsy is the gold standard for diagnosis, it primarily reveals tissue morphology. In contrast, near-infrared (NIR) microscopy offers a label-free method for detailed molecular characterization of kidney tissue. Hematoxylin and eosin-stained kidney tissue samples from 17 ob/ob mice with DN and 14 healthy mice were examined using Fourier transform-NIR microscopy. Four different spectra were obtained from both the mesangium and tubulus. NIR spectral analysis unveiled distinct differences in wavenumbers between DN-affected and healthy kidneys, notably in the carbohydrate and protein-associated region (5500-4200 cm-1). In the mesangium, DN tissue samples exhibited higher median values at 4235 cm-1, 4659 cm-1, 4844 cm-1, 4906 cm-1, and 5222 cm-1 compared to controls (P < 0.05, P < 0.01, P < 0.05, P < 0.05 and P < 0.001, respectively). In tubular spectra, higher median values were found at 4258 cm-1, 4659 cm-1, 5222 cm-1, and 5346 cm-1 in the DN group (P < 0.01, P < 0.05, P < 0.05 and P < 0.01, respectively). These spectral differences strongly correlated with metabolic, histologic, and urinary parameters, providing valuable DN progression insights. The classification model achieved a visible clustering between the control and DN group for both the mesangial and tubular measurements. NIR microscopy demonstrated significant spectral differences between DN and healthy kidney tissues in mice, hinting at its potential for providing chemical insights, aiding in more accurate diagnoses, and offering a foundation for further clinical exploration and potential therapeutic advancements in DN.

Risk Evaluation of Progression of Proteinuria and Renal Decline Based on a Novel Subgroup Classification in Chinese Patients with Type 2 Diabetes

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is a highly heterogeneous disease with a varying risk of complications. The recent novel subgroup classification using cluster analysis contributed to the risk evaluation of diabetic complications. However, whether the subgroup classification strategy could be adopted to predict the risk of onset and progression of diabetic kidney disease (DKD) in Chinese individuals with T2DM remains to be elucidated.

METHODS

In this retrospective study, 612 Chinese patients with T2DM were enrolled, and the median follow-up time was 3.5 years. The T2DM subgroups were categorized by a two-step cluster analysis based on five parameters, including age at onset of diabetes, body mass index (BMI), glycosylated hemoglobin (HbA1c), homeostasis model assessment 2 of insulin resistance (HOMA2-IR), and homeostasis model assessment 2 of β-cell function (HOMA2-β). Clinical characteristics across subgroups were compared using t-tests and chi-square tests. Furthermore, multivariate logistic regression models were adopted to assess the risk of albuminuria progression and renal function decline among different subgroups.

RESULTS

The cohort was categorized into four groups: severe insulin-deficient diabetes (SIDD), with 146 patients (23.9%); mild insulin resistance (MIRD), with 81 patients (13.2%); moderate glycemic control diabetes (MGCD), with 211 patients (34.5%); and moderate weight insulin deficiency diabetes (MWIDD), with 174 patients (28.4%). The MIRD group exhibited an increased risk of progression from non-albuminuria to albuminuria as compared with the MWIDD group, with an adjusted odds ratio (OR) and 95% confidence interval (CI) of 2.92 (1.06, 8.04). The SIDD group had a higher risk of progression from micro-albuminuria to macro-albuminuria as compared with the MGCD group, with an adjusted OR and 95% CI of 3.39 (1.01, 11.41). There was no significant difference in the glomerular filtration rate (GFR) decline among all groups.

CONCLUSION

The present study offered the first evidence for risk evaluation of the development of DKD in the novel cluster-based T2DM Chinese subgroups. It suggested that the MIRD subgroup had a higher risk of DKD onset than the MWIDD subgroup. Meanwhile, the SIDD subgroup showed a higher risk of progression of albuminuria than the MGCD subgroup. This novel classification system could be effective in predicting the risk of DKD in Chinese patients with T2DM, which could facilitate the implementation of personalized therapeutic strategies.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (ChiCTR2300077183).

Unraveling the rationale and conducting a comprehensive assessment of AdipoRon (adiponectin receptor agonist) as a candidate drug for diabetic nephropathy and cardiomyopathy prevention and intervention-a systematic review

Type 2 diabetes mellitus (T2DM) is a widespread chronic disease characterized by persistent hyperglycemia, leading to severe complications such as diabetic cardiomyopathy and nephropathy, significantly affecting patient health and quality of life. The complex mechanisms underlying these complications include chronic inflammation, oxidative stress, and metabolic dysregulation. Diabetic cardiomyopathy, marked by structural and functional heart abnormalities, and diabetic nephropathy, characterized by progressive kidney damage, are major contributors to the increased morbidity and mortality associated with T2DM. AdipoRon, a synthetic adiponectin receptor agonist, has shown potential in preclinical studies for mimicking the beneficial effects of endogenous adiponectin, reducing inflammation and oxidative stress, and improving lipid metabolism and mitochondrial function. This systematic review evaluates the therapeutic potential of AdipoRon, focusing on its impact on diabetic cardiomyopathy and nephropathy. Through a comprehensive literature search and analysis, we highlight AdipoRon's role in ameliorating cardiovascular and renal complications in various animal models and cellular systems. The findings underscore the urgent need for translational clinical studies to validate AdipoRon's efficacy and safety in human populations, aiming to advance this promising therapeutic approach from experimental models to clinical application, potentially offering new hope for improved management of diabetic complications.

Lipid nephrotoxicity mediated by HIF-1α activation accelerates tubular injury in diabetic nephropathy

This study is intended to explore the effect of hypoxia-inducible factor-1α (HIF-1α) activation on lipid accumulation in the diabetic kidney. A type 1 diabetic rat model was established by STZ intraperitoneal injection. Cobalt chloride (CoCl2) and YC-1 were used as the HIF-1α activator and antagonist, respectively. CoCl2 treatment significantly increased HIF-1α expression, accelerated lipid deposition, and accelerated tubular injury in diabetic kidneys. In vitro, CoCl2 effectively stabilized HIF-1α and increased its transportation from the cytoplasm to the nucleus, which was accompanied by significantly increased lipid accumulation in HK-2 cells. Furthermore, results obtained in vivo showed that HIF-1α protein expression in the renal tubules of diabetic rats was significantly downregulated by YC-1 treatment. Meanwhile, lipid accumulation in the tubules of the DM + YC-1 group was markedly decreased in comparison to the DM + DMSO group. Accordingly, PAS staining revealed that the pathological injury caused to the tubular epithelial cells was alleviated by YC-1 treatment. Furthermore, the blood glucose level, urine albumin creatinine ratio, and NAG creatinine ratio in the DM + YC-1 group were significantly decreased compared to the DM + DMSO group. Moreover, the protein expression levels of transforming growth factor β1 (TGF-β1) and connective tissue growth factor (CTGF) in diabetic kidneys were decreased by YC-1 treatment. Our findings demonstrate that the activation of HIF-1α contributed to interstitial injury in a rat model of diabetic nephropathy and that the underlying mechanism involved the induction of lipid accumulation.

Role of Bile Acid Receptors in the Development and Function of Diabetic Nephropathy

Diabetic nephropathy (DN) is a prevalent microvascular complication that occurs often in individuals with diabetes. It significantly raises the mortality rate of affected patients. Therefore, there is an urgent need to identify therapeutic targets for controlling and preventing the occurrence and development of DN. Bile acids (BAs) are now recognized as intricate metabolic integrators and signaling molecules. The activation of BAs has great promise as a therapeutic approach for preventing DN, renal damage caused by obesity, and nephrosclerosis. The nuclear receptors (NRs), farnesoid X receptor (FXR), pregnane X receptor (PXR), vitamin D receptor (VDR); and the G protein-coupled BA receptor, Takeda G-protein-coupled receptor 5 (TGR5) have important functions in controlling lipid, glucose, and energy metabolism, inflammation, as well as drug metabolism and detoxification. Over the past 10 years, there has been advancement in comprehending the biology and processes of BA receptors in the kidney, as well as in the creation of targeted BA receptor agonists. In this review, we discuss the role of BA receptors, FXR, PXR, VDR, and TGR5 in DN and their role in renal physiology, as well as the development and application of agonists that activate BA receptors for the treatment of kidney diseases.

Proteinuria Assessment and Therapeutic Implementation in Chronic Kidney Disease Patients-A Clinical Audit on KDIGO ("Kidney Disease: Improving Global Outcomes") Guidelines

Background/Objectives: Chronic kidney disease (CKD) is a major health problem with a rising prevalence due to comorbidities like diabetes and hypertension. The aim of this research was to audit the assessment and therapeutic management of proteinuria in CKD patients at the Cantonal Hospital Baselland (KSBL) in Switzerland and determine associations between patient comorbidities, rehospitalisation, death, and the quality of therapeutic management. Methods: We analysed data from 427 adults with CKD (eGFR < 45 mL/min/1.73 m2) hospitalised on the internal medicine ward in 2022. Results: The mean age was 85 years (range: 79-89), 45.9% were female, and the median eGFR was 32.8 mL/min/1.73 m2 (range: 25-40). Proteinuria assessment was performed in 120 (28.1%) patients (the ProtU group), and a corresponding treatment was prescribed in 59%. The ProtU group had a higher quota of patients with diabetes (44.1% vs. 33%, p = 0.048) and obesity (21.2% vs. 12.5%, p = 0.039) when compared to the group without proteinuria assessment (the Ustix group). Twelve-month survival was not significantly different between the groups (HR: 0.75; 95% CI: 0.488-1.154; p-value = 0.191). However, survival was significantly better in patients who received an antiproteinuric treatment compared to those who did not (HR: 0.30; 95% CI: 0.121-0.0761; p = 0.011). Conclusions: Improvements need to be made in managing CKD at the KSBL in accordance with the guidelines.

Serum L C3-II levels in type 2 diabetic patients with impaired renal functions

This study was designed to evaluate serum LC3-II, BCL-2, IL-1β, TGF-β1, and podocin levels in. type 2 diabetes (T2DM) patients with renal dysfunction.

MATERIALS

176 Turkish subjects were enrolled, of whom 26 were healthy, and 150 had T2DM.

PATIENTS

were classified according to albumin urea ratio: 88 patients had macroalbuminuria, 20. patients had microalbuminuria, and 42 had normoalbuminuria. T2DM patients were also. classified into three groups according to proteinuria and eGFR stages.

RESULTS

Increased serum LC3-II levels in patients with T2DM with increased urinary albumin. extraction and impaired renal functions. There was a strong relationship between serum. LC3-II levels and serum BCL-2, IL-1β, TGF-β1, and Podocin levels. The efficiency of LC3- II as a diagnostic biomarker in the differential diagnosis of DM patients with. macroproteinuria from DM patients with normoproteinuria was 75.4%.

CONCLUSIONS

It was thought that increased serum LC3-II levels in T2DM patients with impaired renal. functions may cause renal podocyte damage. In these patients, serum LC3-II levels can be. evaluated as a new biomarker to follow the development of renal damage.

Urolithin A Ameliorates the TGF Beta-Dependent Impairment of Podocytes Exposed to High Glucose

Increased activity of transforming growth factor-beta (TGF-β) is a key factor mediating kidney impairment in diabetes. Glomerular podocytes, the crucial component of the renal filter, are a direct target of TGF-β action, resulting in irreversible cell loss and progression of chronic kidney disease (CKD). Urolithin A (UA) is a member of the family of polyphenol metabolites produced by gut microbiota from ellagitannins and ellagic acid-rich foods. The broad spectrum of biological activities of UA makes it a promising candidate for the treatment of podocyte disorders. In this in vitro study, we investigated whether UA influences the changes exerted in podocytes by TGF-β and high glucose. Following a 7-day incubation in normal (NG, 5.5 mM) or high (HG, 25 mM) glucose, the cells were treated with UA and/or TGF-β1 for 24 h. HG and TGF-β1, each independent and in concert reduced expression of nephrin, increased podocyte motility, and up-regulated expression of b3 integrin and fibronectin. These typical-for-epithelial-to-mesenchymal transition (EMT) effects were inhibited by UA in both HG and NG conditions. UA also reduced the typically elevated HG expression of TGF-β receptors and activation of the TGF-β signal transducer Smad2. Our results indicate that in podocytes cultured in conditions mimicking the diabetic milieu, UA inhibits and reverses changes underlying podocytopenia in diabetic kidneys. Hence, UA should be considered as a potential therapeutic agent in podocytopathies.

Piperazine ferulate inhibits diabetic nephropathy by suppressing AGE/RAGE-mediated inflammatory signaling in rats and podocytes

Objective: Diabetic nephropathy (DN) is a serious complication that may occur during the later stages of diabetes, and can be further exacerbated by podocyte damage. Piperazine ferulate (PF) has well-defined nephroprotective effects and is used clinically in the treatment of chronic nephritis and other kidney diseases. However, the renoprotective effects and mechanisms of PF on DN are not clear. This study aims to investigate the protective effect of PF on DN and its mechanism of action, to inform the clinical application of PF in DN treatment. Methods: Network pharmacology was performed to predict the mechanism of action of PF in DN. Male Sprague Dawley rats were intraperitoneally injected with STZ (60 mg/kg) to establish a DN model, and then assessed for renal injury after 12 weeks of administration. In vitro, rat podocytes were treated with 25 mmol/L glucose and cultured for 24 h, followed by an assessment of cell injury. Results: Our results showed that PF significantly improved renal function, reduced renal pathological changes, decreased inflammatory response, and alleviated podocyte damage in DN rats. PF also attenuated glucose-induced podocyte injury in vitro. Regarding molecular mechanisms, our study demonstrated that PF downregulated the expression of genes and proteins related to AGE-RAGE-mediated inflammatory signaling. Conclusion: In summary, PF exerts its renoprotective effects by decreasing inflammation and protecting against podocyte injury through the inhibition of the AGE/RAGE/NF-κB/NLRP3 pathway. Overall, these data support the clinical potential of PF as a renoprotective agent in DN.

A new perspective on proteinuria and drug therapy for diabetic kidney disease

Diabetic kidney disease (DKD) is one of the leading causes of end-stage renal disease worldwide and significantly increases the risk of premature death due to cardiovascular diseases. Elevated urinary albumin levels are an important clinical feature of DKD. Effective control of albuminuria not only delays glomerular filtration rate decline but also markedly reduces cardiovascular disease risk and all-cause mortality. New drugs for treating DKD proteinuria, including sodium-glucose cotransporter two inhibitors, mineralocorticoid receptor antagonists, and endothelin receptor antagonists, have shown significant efficacy. Auxiliary treatment with proprietary Chinese medicine has also yielded promising results; however, it also faces a broader scope for development. The mechanisms by which these drugs treat albuminuria in patients with DKD should be described more thoroughly. The positive effects of combination therapy with two or more drugs in reducing albuminuria and protecting the kidneys warrant further investigation. Therefore, this review explores the pathophysiological mechanism of albuminuria in patients with DKD, the value of clinical diagnosis and prognosis, new progress and mechanisms of treatment, and multidrug therapy in patients who have type 2 diabetic kidney disease, providing a new perspective on the clinical diagnosis and treatment of DKD.

Urine biomarkers in type 2 diabetes mellitus with or without microvascular complications

OBJECTIVE

To investigate the distribution of nine (9) urine biomarkers in people living with type 2 diabetes mellitus (T2DM), with or without microvascular complications.

METHODS

In total, 407 people with T2DM were enrolled from 2021 to 2022. According to diabetic retinopathy (DR) and urinary albumin-creatinine ratio (UACR), the 407 people were divided into four (4) groups, DR(-)UACR(-), DR(+)UACR(-), DR(-)UACR(+), and DR( + )UACR(+). In addition, 112 healthy volunteers were enrolled during the same period. The nine (9) urine markers included α1-microglobulin (u-α1MG), immunoglobulin G (u-IgG), neutrophil gelatinase-associated lipid carrier protein (u-NGAL), cystatin C (u-CysC), retinol-binding protein (u-RBP), β2-microglobulin (u-β2MG), N-acetyl-β-D-glucosaminidase (u-NAG), transferrin (u-Trf), and collagen type IV (u-Col). For each marker, the respective level of 97.5 percentile in healthy volunteers was taken as an upper reference limit.

RESULTS

Among the 407 people, 248 individuals (61%) were DR(-)UACR(-), 100 (25%) were DR(-)UACR(+), 37 (9%) were DR(+)UACR(-), and 22 (5%) were DR(+)UACR(+). The u-NAG/Cr biomarker level showed a significant difference between healthy participants and people with T2DM. In the DR(-)UACR(-)group, u-Trf/Cr showed the highest positive rate (21.37%), followed by u-IgG/Cr (14.52%); u-NAG/Cr (10.48%); u-β2MG/Cr (4.44%); u-CysC/Cr (4.03%); u-NGAL/Cr (4.03%); u-RBP/Cr (2.82%); u-α1MG/Cr (2.42%); 17.34% of people with T2DM showed multiple biomarkers positive (≥2 biomarkers). The positive rates of one biomarker (21.33%) and two biomarkers (18.67%) in people who have less than five (5) years of T2DM were almost close to those of the DR(-)UACR(-) group (21.37%, and 12.10%, respectively).

CONCLUSION

Renal tubule biomarkers may be used as an indicator in the early detection and monitoring of renal injury in diabetes mellitus. The u-NAG biomarker should be measured for the people with T2DM of the first-time diagnosis.

Renal handling of albumin in rats with early stage diabetes: A theoretical analysis

In early diabetic nephropathy (DN), recent studies have shown that albuminuria stems mostly from alterations in tubular function rather than from glomerular damage. Several factors in DN, including hyperfiltration, hypertrophy and reduced abundance of the albumin receptors megalin and cubilin, affect albumin endocytosis in the proximal tubule (PT). To assess their respective contribution, we developed a model of albumin handling in the rat PT that couples the transport of albumin to that of water and solutes. Our simulations suggest that, under basal conditions, ∼75% of albumin is retrieved in the S1 segment. The model predicts negligible uptake in S3, as observed experimentally. It also accurately predicts the impact of acute hyperglycaemia on urinary albumin excretion. Simulations reproduce observed increases in albumin excretion in early DN by considering the combined effects of increased glomerular filtration rate (GFR), osmotic diuresis, hypertrophy, and megalin and cubilin downregulation, without stipulating changes in glomerular permselectivity. The results indicate that in isolation, glucose-elicited osmotic diuresis and glucose transporter upregulation raise albumin excretion only slightly. Enlargement of PT diameter not only augments uptake via surface area expansion, but also reduces fluid velocity and thus shear stress-induced stimulation of endocytosis. Overall, our model predicts that downregulation of megalin and cubilin and hyperfiltration both contribute significantly to increasing albumin excretion in rats with early-stage diabetes. The results also suggest that acute sodium-glucose cotransporter 2 inhibition lowers albumin excretion only if GFR decreases sufficiently, and that angiotensin II receptor blockers mitigate urinary albumin loss in early DN in large part by upregulating albumin receptor abundance. KEY POINTS: The urinary excretion of albumin is increased in early diabetic nephropathy (DN). It is difficult to experimentally disentangle the multiple factors that affect the renal handling of albumin in DN. We developed a mathematical model of albumin transport in the rat proximal tubule (PT) to examine the impact of elevated plasma glucose, hyperfiltration, PT hypertrophy and reduced abundance of albumin receptors on albumin uptake and excretion in DN. Our model predicts that glucose-elicited osmotic diuresis per se raises albumin excretion only slightly. Conversely, increases in PT diameter and length favour reduced albumin excretion. Our results suggest that downregulation of the receptors megalin and cubilin in PT cells and hyperfiltration both contribute significantly to increasing albumin excretion in DN. The model helps to better understand the mechanisms underlying urinary loss of albumin in early-stage diabetes, and the impact of specific treatments thereupon.

Low Protein Diet Reduces Proteinuria and Decline in Glomerular Filtration Rate in Advanced, Heavy Proteinuric Diabetic Kidney Disease

Low protein diet (LPD) seems beneficial in ameliorating the complications of chronic kidney disease (CKD), in reducing proteinuria and the decline in kidney function, thus postponing the need for kidney replacement therapy (KRT). However, this type of intervention was less investigated in diabetic kidney disease (DKD). This is a single-center, prospective, interventional study that aims to assess the efficacy of reducing proteinuria and the rate of decline in the estimated glomerular filtration rate (eGFR). Patients with advanced DKD (stable proteinuria > 3 g/g and eGFR < 30 mL/min) with a good nutritional status and accepting a LPD were evaluated for inclusion. Ninety-two of the 452 screened patients (66% males, median age 61 years, proteinuria 4.8 g/g creatininuria, eGFR 11.7 mL/min/1.73 m2) completed the study. Intervention consisted of LPD supplemented with ketoanalogues of essential amino acids (KA) along with conventional nephroprotective therapy. Efficacy parameters were the variation in proteinuria and in eGFR from baseline to the end of the study. Proteinuria decreased 3-fold, and the rate of decline in eGFR decreased 5-fold in the intervention phase. No patient initiated KRT or died. LPD supplemented with KA seems effective in safely postponing KRT by reducing proteinuria and the decline in kidney function in advanced DKD.

Non-steroidal mineralocorticoid antagonists and hyperkalemia monitoring in chronic kidney disease patients associated with type II diabetes: a narrative review

Chronic kidney disease (CKD) is a prevalent complication of Type II diabetes (T2D). The coexistence of CKD with T2D is comparable to cardiovascular disease (CVD) when the estimated glomerular filtration rate declines below 60 ml/min/1.73 m2. Screening and early detection of people with high risk for CKD would be beneficial in managing CKD progress and the associated complications such as CV complications. Renin-angiotensin-aldosterone system inhibitors (RAASi) have demonstrated beneficial effects in delaying CKD progression, but they carry the risk of hyperkalemia. Nonsteroidal mineralocorticoid antagonists (nsMRA), such as finerenone, exhibit considerable efficacy in their anti-inflammatory, antifibrotic, and renal protective effects with demonstrable reductions in CV complications. In addition, nsMRAs do not cause significant changes in serum potassium levels compared to traditional steroidal MRA. Ongoing research explores the capacity of the sodium-glucose transport protein 2 inhibitors (SGLT-2i), combined with nsMRA, to produce synergistic renal protective effects and reduce the risk of hyperkalemia. Also, a dedicated renal outcomes study (FLOW study) involving a once-weekly injectable Glucagon-like peptide-1 receptor agonist, semaglutide, was halted early by the data monitoring committee due to having achieved the predefined efficacy endpoint and considerations related to renal disease. In CKD patients with T2D on nsMRA, hyperkalemia management requires a comprehensive approach involving lifestyle adjustments, dietary modifications, regular serum potassium level monitoring, and potassium binders, if necessary. Withholding or down-titration of nsMRAs with close monitoring of serum potassium levels may be required in patients with concerning potassium levels. In light of the current state of knowledge, this review article explores the perspectives and approaches that HCPs may consider when monitoring and managing hyperkalemia in CKD patients with T2D.

Unveiling the pathogenesis and therapeutic approaches for diabetic nephropathy: insights from panvascular diseases

Diabetic nephropathy (DN) represents a significant microvascular complication in diabetes, entailing intricate molecular pathways and mechanisms associated with cardiorenal vascular diseases. Prolonged hyperglycemia induces renal endothelial dysfunction and damage via metabolic abnormalities, inflammation, and oxidative stress, thereby compromising hemodynamics. Concurrently, fibrotic and sclerotic alterations exacerbate glomerular and tubular injuries. At a macro level, reciprocal communication between the renal microvasculature and systemic circulation establishes a pernicious cycle propelling disease progression. The current management approach emphasizes rigorous control of glycemic levels and blood pressure, with renin-angiotensin system blockade conferring renoprotection. Novel antidiabetic agents exhibit renoprotective effects, potentially mediated through endothelial modulation. Nonetheless, emerging therapies present novel avenues for enhancing patient outcomes and alleviating the disease burden. A precision-based approach, coupled with a comprehensive strategy addressing global vascular risk, will be pivotal in mitigating the cardiorenal burden associated with diabetes.

Total flavonoids of Astragalus protects glomerular filtration barrier in diabetic kidney disease

BACKGROUND

Diabetic kidney disease (DKD) is a prevalent complication of diabetes and the leading cause of end-stage renal disease. Recent evidence suggests that total flavonoids of Astragalus (TFA) has promising effects on diabetes; however, its influence on DKD and the underlying mechanism remains unclear.

METHODS

In this study, we induced the DKD model using streptozotocin (STZ) in male C57BL/6J mice and utilized glomerular endothelial cell (GEC) lines for in vitro investigations. We constructed a network pharmacology analysis to understand the mechanism of TFA in DKD. The mechanism of TFA action on DKD was investigated through Western blot analysis and multi-immunological methods.

RESULTS

Our findings revealed that TFA significantly reduced levels of urinary albumin (ALB). Network pharmacology and intracellular pathway experiments indicated the crucial involvement of the PI3K/AKT signaling pathway in mediating these effects. In vitro experiments showed that TFA can preserve the integrity of the glomerular filtration barrier by inhibiting the expression of inflammatory factors TNF-alpha and IL-8, reducing oxidative stress.

CONCLUSION

Our findings demonstrated that TFA can ameliorates the progression of DKD by ameliorating renal fibrosis and preserving the integrity of the kidney filtration barrier. These results provide pharmacological evidence supporting the use of TFA in the treatment of kidney diseases.

The Mechanism of Plantaginis Semen in the Treatment of Diabetic Nephropathy based on Network Pharmacology and Molecular Docking Technology

BACKGROUND

Diabetic nephropathy (DN) is one of the common complications of diabetes. Plantaginis Semen (PS) has a variety of therapeutic effects, however its mechanism on DN is unclear.

OBJECTIVE

This paper aims to find the ingredients, the key targets, and the action pathways of PS on DN from the perspective of network pharmacology.

METHODS

The databases of network pharmacology, such as Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), Pharmmapper, OMIM, DrugBank, Gene- Cards, TTD, Disgenet, STRING, and Cytoscape software, were used to find the main ingredients and targets. Gene Ontology (GO) function and Kyoto Encyclopedia of Genome and Genomes (KEGG) pathway enrichment analysis were used to reveal the potential pathways of the PS on DN. The GEO database was used to find the targets of DN based on valid experimental research. The molecular docking technology was used to evaluate the combination between ingredients of PS and the targets.

RESULTS

A total of 9 active ingredients and 216 potential therapeutic targets were obtained for PS on DN. Hub targets were discovered by the Cytoscape software analysis. CASP3 was screened by Venn diagram by making intersection between GSE30529 and hub genes. Moreover, CASP3 was combined with one of the nine active ingredients, quercetin, by molecular docking analysis. The KEGG pathways were mainly involved in diabetic nephropathy, and were simultaneously associated with CASP3 as followed: AGE-RAGE signaling pathway in diabetic complications, apoptosis, lipid and atherosclerosis, MAPK signaling pathway, TNF signaling pathway, IL-17 signaling pathway, and p53 signaling pathway.

CONCLUSION

PS can have the treatment on DN through CASP3. Quercetin, as one of the nine active ingredients, can be bounded to CASP3 to inhibit apoptosis in DN. PS can also take action on DN probably through many pathways. The role of PS on DN through other pathways still needs to be further elaborated.

Narrative review investigating the nephroprotective mechanisms of sodium glucose cotransporter type 2 inhibitors in diabetic and nondiabetic patients with chronic kidney disease

Background and aims

Outcome trials using sodium glucose cotransporter type 2 inhibitors have consistently shown their potential to preserve kidney function in diabetic and nondiabetic patients. Several mechanisms have been introduced which may explain the nephroprotective effect of sodium glucose cotransporter type 2 inhibitors beyond lowering blood glucose. This current narrative review has the objective to describe main underlying mechanisms causing a nephroprotective effect and to show similarities as well as differences between proposed mechanisms which can be observed in patients with diabetic and nondiabetic chronic kidney disease.

Methods

We performed a narrative review of the literature on Pubmed and Embase. The research string comprised various combinations of items including "chronic kidney disease", "sodium glucose cotransporter 2 inhibitor" and "mechanisms". We searched for original research and review articles published until march, 2022. The databases were searched independently and the agreements by two authors were jointly obtained.

Results

Sodium glucose cotransporter type 2 inhibitors show systemic, hemodynamic, and metabolic effects. Systemic effects include reduction of blood pressure without compensatory activation of the sympathetic nervous system. Hemodynamic effects include restoration of tubuloglomerular feedback which may improve pathologic hyperfiltration observed in most cases with chronic kidney disease. Current literature indicates that SGLT2i may not improve cortical oxygenation and may reduce medullar oxygenation.

Conclusion

Sodium glucose cotransporter type 2 inhibitors cause nephroprotective effects by several mechanisms. However, several mediators which are involved in the underlying pathophysiology may be different between diabetic and nondiabetic patients.

Incidence and risk factors of asymptomatic bacteriuria in patients with type 2 diabetes mellitus: a meta-analysis

BACKGROUND

The prevalence of type 2 diabetes mellitus (T2DM) is increasing each year and has become one of the most prominent health concerns worldwide. Patients with T2DM are prone to infectious diseases, and urinary tract infections are also widespread. Despite a comprehensive understanding of urinary tract infection (UTI), there is a lack of research regarding primary prevention strategies for asymptomatic bacteriuria (ASB).

OBJECTIVE

To clarify the incidence and risk factors of asymptomatic urinary tract infection in patients with T2DM by meta-analysis to provide evidence for preventing UTI. Help patients, their families, and caregivers to identify the risk factors of patients in time and intervene to reduce the incidence of ASB in patients with T2DM. Fill in the gaps in existing research.

STUDY DESIGN

Meta-analyses were conducted in line with PRISMA guidelines.

METHODS

Eleven databases were systematically searched for articles about ASB in T2DM, and the retrieval time was selected from the establishment of the database to February 5, 2023. Literature screening, quality evaluation, and meta-analysis were independently performed by two researchers according to the inclusion and exclusion criteria, and a meta-analysis was performed using Stata 17.0.

RESULTS

Fourteen articles were included, including cohort and case-control studies. A meta-analysis of 4044 patients with T2DM was included. The incidence of ASB in patients with T2DM was 23.7%(95% CI (0.183, 0.291); P < 0.001). After controlling for confounding variables, the following risk factors were associated with ASB in patients with T2DM: age (WMD = 3.18, 95% CI (1.91, 4.45), I2 = 75.5%, P < 0.001), female sex (OR = 1.07, 95% CI(1.02, 1.12), I2 = 79.3%, P = 0.002), duration of type 2 diabetes (WMD = 2.54, 95% CI (1.53, 5.43), I2 = 80.7%, P < 0.001), HbA1c (WMD = 0.63, 95% CI (0.43, 0.84), I2 = 62.6,%. P < 0.001), hypertension (OR = 1.59, 95% CI (1.24, 2.04), I2 = 0%, <0.001), hyperlipidemia (OR = 1.66, 95% CI (1.27, 2.18), I2 = 0%, P < 0.001), Neuropathy (OR = 1.81, 95% CI (1.38, 2.37), I2 = 0%, P < 0.001), proteinuria (OR = 3.00, 95% CI (1.82, 4.95), I2 = 62.7%, P < 0.001).

CONCLUSION

The overall prevalence of ASB in T2DM is 23.7%. Age, female sex, course of T2DM, HbA1C, hypertension, hyperlipidemia, neuropathy, and proteinuria were identified as related risk factors for ASB in T2DM. These findings can provide a robust theoretical basis for preventing and managing ASB in T2DM.

Early diagnosis of chronic kidney disease in patients with diabetes in France: multidisciplinary expert opinion, prevention value and practical recommendations

Diabetes is the leading cause of end-stage kidney disease (ESKD), accounting for approximately 50% of patients starting dialysis. However, the management of these patients at the stage of chronic kidney disease (CKD) remains poor, with fragmented care pathways among healthcare professionals (HCPs). Diagnosis of CKD and most of its complications is based on laboratory evidence. This article provides an overview of critical laboratory evidence of CKD and their limitations, such as estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio (UACR), Kidney Failure Risk Equation (KFRE), and serum potassium. eGFR is estimated using the CKD-EPI 2009 formula, more relevant in Europe, from the calibrated dosage of plasma creatinine. The estimation formula and the diagnostic thresholds have been the subject of recent controversies. Recent guidelines emphasized the combined equation using both creatinine and cystatin for improved estimation of GFR. UACR on a spot urine sample is a simple method that replaces the collection of 24-hour urine. Albuminuria is the preferred test because of increased sensitivity but proteinuria may be appropriate in some settings as an alternative or in addition to albuminuria testing. KFRE is a new tool to estimate the risk of progression to ESKD. This score is now well validated and may improve the nephrology referral strategy. Plasma or serum potassium is an important parameter to monitor in patients with CKD, especially those on renin-angiotensin-aldosterone system (RAAS) inhibitors or diuretics. Pre-analytical conditions are essential to exclude factitious hyperkalemia. The current concept is to correct hyperkalemia using pharmacological approaches, resins or diuretics to be able to maintain RAAS blockers at the recommended dose and discontinue them at last resort. This paper also suggests expert recommendations to optimize the healthcare pathway and the roles and interactions of the HCPs involved in managing CKD in patients with diabetes.

Bioactive NIR-II gold clusters for three-dimensional imaging and acute inflammation inhibition

Strong fluorescence and high catalytic activities cannot be achieved simultaneously due to conflicts in free electron utilization, resulting in a lack of bioactivity of most near-infrared-II (NIR-II) fluorophores. To circumvent this challenge, we developed atomically precise Au22 clusters with strong NIR-II fluorescence ranging from 950 to 1300 nm exhibiting potent enzyme-mimetic activities through atomic engineering to create active Cu single-atom sites. The developed Au21Cu1 clusters show 18-fold higher antioxidant, 90-fold higher catalase-like, and 3-fold higher superoxide dismutase-like activities than Au22 clusters, with negligible fluorescence loss. Doping with single Cu atoms decreases the bandgap from 1.33 to 1.28 eV by predominant contributions from Cu d states, and Cu with lost electron states effectuates high catalytic activities. The renal clearable clusters can monitor cisplatin-induced renal injury in the 20- to 120-minute window and visualize it in three dimensions using NIR-II light-sheet microscopy. Furthermore, the clusters inhibit oxidative stress and inflammation in the cisplatin-treated mouse model, particularly in the kidneys and brain.

Cardiovascular Outcomes in Patients With Diabetes and Kidney Disease: JACC Review Topic of the Week

Chronic kidney disease (CKD) and cardiovascular disease (CVD) have a significant inter-relationship in patients with diabetes. Controlling blood pressure, dyslipidemia, and glucose levels is a common treatment approach to managing CVD risk in patients with CKD and diabetes; despite strict control, however, a high residual risk remains. This review focuses on patients who require pharmacotherapy, in whom new and existing cardiorenal therapies (renin-angiotensin-aldosterone system inhibitors, sodium-glucose cotransporter-2 inhibitors, glucagon-like peptide-1 receptor agonists, and nonsteroidal mineralocorticoid receptor antagonists) with differing mechanisms of action and safety profiles can reduce cardiovascular risk beyond the outcomes achieved with blood pressure, dyslipidemia, or glycemic control alone. Several treatment guidelines have been updated recently to reflect new evidence. Studies of these cardiorenal agents used in combination are ongoing, and results are awaited with interest, with the hope that potential synergistic effects may lead to further improvements in cardiovascular outcomes.

Identification of the molecular mechanism and candidate markers for diabetic nephropathy

Background

Diabetic nephropathy (DN) is one of the most common complications in diabetic patients. New strategies are needed to delay the occurrence and development of this pathology.

Methods

Differentially expressed genes (DEGs) in glomeruli and renal tubules were identified using the GSE30122 dataset, and a co-expression network was constructed to identify the hub genes of modules. The biological function and signaling pathway of the module genes were also analyzed. In addition, the expression of 24 immune cells and the area under the receiver operating characteristic (ROC) curve (AUC) values of the hub genes were also calculated.

Results

A total of 1,778 DEGs were isolated from glomeruli and 1,996 DEGs were isolated from renal tubules. Nine modules and their hub genes were identified using the co-expression network. Enrichment analysis showed that the module genes were mainly enriched in immune inflammation and oxidative stress. The expressions of B cells, activated dendritic cell, and T cells in the glomeruli and renal tubules of DN patients were higher than those in the controls, and the correlation between these immune cells was the strongest. Collagen type I alpha 2 chain (COL1A2), the hub gene of the brown module, had the highest AUC values and may have a better clinical diagnostic ability.

Conclusions

In conclusion, the module genes and related biological functions and signaling pathways found in this study can deepen our understanding of the molecular mechanism of DN progression. COL1A2 may be a potential biomarker for DN.