Molecular Mechanisms and Therapeutic Targets for Diabetic Kidney Disease

Association between life's essential 8 and diabetic kidney disease: a population-based study

BACKGROUND AND AIMS

Diabetic patients are highly susceptible to cardiovascular and renal diseases. As a newly updated comprehensive index for assessing cardiovascular health (CVH), Life's essential 8 (LE8) has the potential to serve as a practical tool for evaluating the risk of diabetic kidney disease (DKD). We are committed to exploring the relationship between LE8 and its subscales with DKD in diabetic patients, aiming to provide preliminary evidence for the formulation of clinical strategies.

METHODS AND RESULTS

A total of 3,715 NHANES participants were included in this study, representing 18.9 million non-institutionalized residents of the United States. The mean age of all subjects was 59.72 years, and the weighted prevalence of DKD among diabetic patients was 36.39%. After adjusting for potential confounding factors, it was found that compared to the low LE8 group, the risk of developing DKD was significantly lower in the moderate LE8 group (OR: 0.54, 95% CI: 0.43-0.66) and the high LE8 group (OR: 0.18, 95% CI: 0.08-0.42). A similar trend was observed across the subscales of the LE8 score. The results of the fully adjusted restricted cubic spline regression analysis revealed a linear relationship between LE8 and its subscales with DKD. The findings remained consistent in subgroup and sensitivity analyses, with no significant interactions observed between subgroups.

CONCLUSION

Higher scores on the LE8 and its subscales were associated with a lower risk of developing DKD. However, the long-term causal relationship between LE8 and DKD risk necessitates further validation and exploration through large-scale, rigorously designed prospective studies.

TGF-β: elusive target in diabetic kidney disease

Transforming growth factor-beta (TGF-β), a cytokine with near omnipresence, is an integral part of many vital cellular processes across the human body. The family includes three isoforms: Transforming growth factor-beta 1, 2, and 3. These cytokines play a significant role in the fibrosis cascade. Diabetic kidney disease (DKD), a major complication of diabetes, is increasing in prevalence daily, and the classical diagnosis of diabetes is based on the presence of albuminuria. The occurrence of nonalbuminuric DKD has provided new insight into the pathogenesis of this disease. The emphasis on multifactorial pathways involved in developing DKD has highlighted some markers associated with tissue fibrosis. In diabetic nephropathy, TGF-β is significantly involved in its pathology. Its presence in serum and urine means that it could be a diagnostic tool while its regulation provides potential therapeutic targets. Completely blocking TGF-β signaling could reach untargeted regions and cause unanticipated effects. This paper reviews the basic details of TGF-β as a cytokine, its role in DKD, and updates on research carried out to validate its candidacy.

Machine learning algorithms for diabetic kidney disease risk predictive model of Chinese patients with type 2 diabetes mellitus

BACKGROUND

Diabetic kidney disease (DKD) is a common and serious complication of diabetic mellitus (DM). More sensitive methods for early DKD prediction are urgently needed. This study aimed to set up DKD risk prediction models based on machine learning algorithms (MLAs) in patients with type 2 DM (T2DM).

METHODS

The electronic health records of 12,190 T2DM patients with 3-year follow-ups were extracted, and the dataset was divided into a training and testing dataset in a 4:1 ratio. The risk variables for DKD development were ranked and selected to establish forecasting models. The performance of models was further evaluated by the indexes of sensitivity, specificity, positive predictive value, negative predictive value, accuracy, as well as F1 score, using the testing dataset. The value of accuracy was used to select the optimal model.

RESULTS

Using the importance ranking in the random forest package, the variables of age, urinary albumin-to-creatinine ratio, serum cystatin C, estimated glomerular filtration rate, and neutrophil percentage were selected as the predictors for DKD onset. Among the seven forecasting models constructed by MLAs, the accuracy of the Light Gradient Boosting Machine (LightGBM) model was the highest, indicated that the LightGBM algorithms might perform the best for predicting 3-year risk of DKD onset.

CONCLUSIONS

Our study could provide powerful tools for early DKD risk prediction, which might help optimize intervention strategies and improve the renal prognosis in T2DM patients.

Combining mitochondrial proteomes and Mendelian randomization to identify novel therapeutic targets for diabetic nephropathy

Diabetic nephropathy (DN) is a common microvascular complication of diabetes. Mitochondrial dysfunction in the kidney caused by diabetes has previously been linked to the pathogenesis of DN. By mass spectrometry, we identified characteristic proteins of DN from the renal mitochondria in mouse model. To identify the core proteins among them, Mendelian randomization (MR) analysis, microarray data validation, and drug-target interaction analysis were employed. MR analysis found that 189 candidate targets had a causal link with DN risk factors (estimated glomerular filtration rate (eGFR), urinary albumin excretion, and serum creatinine). After systematic analysis, we validated that SLC25A16, CTNND1, C2CD2L, ALDH3A2, NEU1, APEH, CORO1A, NUDT19, and NDUFA4L2 are the core proteins with promising druggability in DN. This study suggests the feasibility of using MR analysis for DN drug target screening, and provides potential insights into mitochondrial dysfunction research, which may contribute to further DN pathogenesis exploration.

Urinary DcR2/Cr level predicts renal outcomes in patients with diabetic kidney disease

In diabetic kidney disease (DKD), urinary decoy receptor 2 (uDcR2) levels are associated with tubulointerstitial fibrosis; however, whether uDcR2 can predict renal outcomes remains unclear. Herein, we analyzed the association between uDcR2 and renal outcomes (defined as a composite of a serum creatinine (SCr) increase of 50 % from baseline, or initiation of dialysis for end-stage renal disease) in 153 patients with biopsy-proven DKD. Patients were divided into the composite (n = 67) and no composite (n = 86) outcome groups. uDcR2 levels were measured using ELISA. The area under the receiver operating characteristic curve (AUC) for uDcR2 in discriminating DKD renal outcomes was calculated. Kaplan-Meier survival analysis and multifactorial Cox regression models evaluated the association between uDcR2 levels and renal outcomes. Renal DcR2 mRNA and protein expression were detected using in situ hybridization and immunohistochemical staining. Immunofluorescence revealed DcR2 and α-SMA colocalization. uDcR2/Cr levels were higher in patients in the composite than the no composite outcome group. uDcR2/Cr levels positively correlated with ACR, SCr, interstitial fibrosis and tubular atrophy (IFTA), and negatively correlated with eGFR. uDcR2/Cr had an AUC of 0.825 at the optimal cut-off value of 389 ng/gCr. Addition of uDcR2/Cr to ACR, eGFR, or IFTA improved renal outcome predictions. Renal survival was significantly lower at uDcR2/Cr ≥ 389 ng/gCr. Patients in the composite group had higher tubular DcR2 mRNA and protein level percentages. α-SMA was significantly increased in DcR2-positive renal tubules and their surroundings. Overall, uDcR2/Cr is an independent predictor of renal outcomes, with potential for improving the prevention and treatment of DKD.

Effectiveness and safety of Tongxinluo capsule for diabetic kidney disease: A systematic review and meta-analysis

BACKGROUND

Diabetic kidney disease (DKD), a common microvascular complication of diabetes mellitus, is the primary cause of end-stage renal disease. Tongxinluo capsule (TXLC), a traditional Chinese medicinal compound, is widely utilized in China for treating DKD.

AIM

To analyze the effectiveness and safety of TXLC for treating DKD.

METHODS

Eight electronic literature databases were retrieved to obtain randomized controlled trials (RCTs) of TXLC for DKD. RevMan 5.3 software was used for data analysis. Evidence quality was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation System. Publication bias was detected using Stata 16.0 software.

RESULTS

Twenty-two RCTs involving 1941 patients with DKD were identified. Compared with conventional treatment, TXLC combination therapy significantly improved the primary outcomes, including 24-hour urine proteinuria, urine microalbumin, and urinary albumin excretion rate. Regarding secondary outcomes, TXLC combination therapy significantly reduced serum creatinine, blood urea nitrogen, β2-microglobulin, and cystatin C levels; however, it had no significant effect on creatinine clearance rate. In terms of additional outcomes, TXLC combination therapy significantly reduced total cholesterol, triglycerides, low-density lipoprotein cholesterol, fibrinogen, plasma viscosity, whole blood low shear viscosity, whole blood high shear viscosity, and endothelin-1 levels, while increasing nitric oxide levels. However, the addition of TXLC treatment did not significantly affect fasting plasma glucose, 2-hour postprandial blood glucose, glycosylated hemoglobin, high-density lipoprotein cholesterol, or C-reactive protein levels. The safety of TXLC in DKD remains uncertain due to limited adverse event reporting.

CONCLUSION

TXLC may benefit individuals with DKD by improving various health parameters, such as urinary protein levels, renal function, blood lipids, hemorheology, and vascular endothelial function. However, TXLC did not improve all studied outcomes.

ASK1 limits kidney glucose reabsorption, growth, and mid-late proximal tubule KIM-1 induction when diabetes and Western diet are combined with SGLT2 inhibition

Selonsertib is an apoptosis signal-regulating kinase 1 inhibitor (ASK1i) that attenuated the decline in creatinine-based estimated GFR in humans with type 2 diabetes and kidney disease but increased the rate of acute kidney injury. This study explored the individual and combined kidney effects of selonsertib and the antihyperglycemic sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin in Western diet-fed male Akita mice, a murine model of early type 1 diabetes mellitus showing signs of systemic but no kidney inflammation. ASK1i reduced elevated plasma levels of proinflammatory cytokines/chemokines (IL-6, MCP1/CCL2, KC/CXCL1, and IP-10/CXCL10) without significantly changing hyperglycemia, glomerular hyperfiltration, and albuminuria or affecting the blood glucose and glomerular hyperfiltration-lowering effect of SGLT2i. A potential sign of tubular stress, SGLT2i modestly upregulated kidney cortex transcription of proinflammatory and profibrotic genes and distal tubule injury marker Ngal. Adding ASK1i to SGLT2i lowered the transcription of many of these genes, including Ngal. However, ASK1i enhanced kidney glucose reabsorption independent of SGLT2i, and combined ASK1i + SGLT2i increased kidney weight by 30%. This was associated with and positively correlated with the upregulation of the tubular stress/injury marker KIM-1, primarily in the mid-to-late proximal tubule. Combined ASK1i + SGLT2i increased the tubular injury score but not signs of kidney inflammation or fibrosis beyond a robust increase in kidney mRNA expression of Il6, Ccl2 (Mcp1), and Timp1, associated with increased plasma IL-6 levels. The data support the hypothesis that housekeeping functions of ASK1 limit glucose reabsorption and the associated growth and cellular stress induced in the mid-to-late proximal tubule by combining hyperglycemia and Western diet with SGLT2 inhibition.NEW & NOTEWORTHY Selonsertib is an apoptosis signal-regulating kinase 1 (ASK1) inhibitor that attenuated creatinine-based eGFR decline in humans with type 2 diabetes and kidney disease but increased acute kidney injury rates. Here, we report evidence in a murine model of early type 1 diabetes mellitus that housekeeping functions of ASK1 limit glucose reabsorption and the associated growth and cellular stress induced in the mid-to-late proximal tubule by combining hyperglycemia and Western diet with SGLT2 inhibition.

Periodontal Care Is Associated With a Lower Risk of Dialysis Initiation in Middle-Aged Patients With Type 2 Diabetes Mellitus: A 6-Year Follow-Up Cohort Study Based on a Nationwide Healthcare Database

OBJECTIVE

To investigate the association between dental attendance with periodontal care and the risk of dialysis initiation in patients with type 2 diabetes mellitus (T2D).

METHODS

This retrospective cohort study used data from the Japan Medical Data Center (JMDC) claims database (January 2015 to August 2022). Patients with T2D, aged 40-74, were included. Dental attendance with periodontal care and initiation of dialysis were used as the exposure and outcome variables, respectively. We fitted the Cox proportional hazards model, including potential confounders, to estimate hazard ratios (HRs) and 95% confidence intervals (95%CIs).

RESULTS

Among 99,273 participants (mean age = 54.4 years [SD = 7.8], male = 71.9%), the incidence rate of dialysis initiation was 0.92 per 1000 person-years. After adjusting for all covariates, those with periodontal care (HR = 0.68 [95%CI = 0.51-0.91] for ≥ 1 time/year and HR = 0.56 [95%CI = 0.41-0.77] for ≥ 1 time/6 months) had a significantly lower risk of dialysis initiation compared to those without dental attendance.

CONCLUSION

Periodontal disease care in patients with T2D is associated with a reduced risk of dialysis initiation by 32%-44%. This suggests that integrating periodontal care into diabetes management may help prevent the progression of diabetic nephropathy and improve patient outcomes.

Dapagliflozin Attenuates Diabetes-Induced Podocyte Lipotoxicity via ERRα-Mediated Lipid Metabolism

Diabetic kidney disease (DKD) is a major complication of diabetes mellitus, characterized by podocyte injury and lipid accumulation, which contribute to high morbidity and mortality. Current treatments primarily alleviate symptoms, underscoring the need for targeted therapies to address the underlying mechanisms of DKD progression. This study explores the protective effects of dapagliflozin (DAPA), a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, on podocyte lipotoxicity and its regulatory role in the estrogen-related receptor alpha (ERRα)-acyl-CoA oxidase 1 (ACOX1) axis. Using db/db mice and streptozotocin-induced DKD models, we demonstrate that DAPA significantly reduces the urinary albumin-to-creatinine ratio (ACR) and improves renal pathology by alleviating glomerular hypertrophy, mesangial matrix expansion, and podocyte foot process effacement. DAPA also decreases triglyceride and free fatty acid accumulation in glomeruli, as evidenced by Oil Red O and BODIPY staining. Mechanistically, DAPA upregulates ERRα and ACOX1 expression in podocytes, enhancing fatty acid oxidation (FAO) and mitigating lipidtoxicity. Loss of ERRα exacerbates lipid-induced podocyte injury, while ERRα overexpression confers protective effects. These findings highlight DAPA's renoprotective effects via modulation of the ERRα-ACOX1 axis, suggesting that targeting ERRα could be a promising therapeutic strategy for DKD.

Association between stress hyperglycemia ratio and acute kidney injury in patients with chronic cardiovascular-kidney disorder: a multi-center retrospective cohort study from China

AIM

Stress hyperglycemia ratio (SHR) is associated with acute kidney injury (AKI) among patients with myocardial infarction. However, the relationship between SHR and AKI in chronic cardiovascular-kidney disorder (CCV-KD) patients are still unknown. This study aimed to clarify the association of SHR with adverse renal outcomes in CCV-KD patients.

METHOD

6,359 CCV-KD patients from the Chinese multi-center registry cohort Cardiorenal ImprovemeNt II (CIN-II) were included in this study. We categorized SHR into distinct groups and conducted logistic analyses to evaluate its association with AKI and progression to end-stage kidney disease (ESKD) or in-hospital dialysis. We also calculated the incidence of these adverse renal outcomes, stratified by estimated glomerular filtration rate (eGFR). Additionally, restricted cubic spline (RCS) was performed to understand the relationship between SHR and adverse renal outcomes.

RESULT

In this study, 13.7% patients experienced AKI and 4.3% patients progressed to ESKD or in-hospital dialysis. Both low SHR (< 0.7) and high SHR (≥ 1.1) were associated with a significantly increased risk of AKI. In addition, high SHR was strongly correlated with an increasing risk of progression to ESKD/dialysis during hospitalization. The incidence of AKI was lowest when the SHR was between 0.9 and 1.1, while the incidence of ESKD was highest when the SHR was ≥ 1.1, across all eGFR subgroups.

CONCLUSION

In patients with CCV-KD, both low and high SHR are associated with an increased risk of AKI development, and elevated SHR is associated with the risk of ESKD/dialysis as well.

Umbilical Cord Mesenchymal Stem Cells Attenuate Podocyte Injury in Diabetic Nephropathy Rats by Inhibiting Angpltl4/Integrin β3 in the Glomerulus

In this study, we investigated the therapeutic effects and mechanisms of umbilical cord mesenchymal stem cells (UCMSCs) in diabetic nephropathy (DN) ZDF (FA/FA) rats. The therapeutic effects were assessed by renal function tests, the urinary albumin-creatinine ratio, PAS staining, electron microscopy, and TGF-β1 expression in renal tissue. Subsequently, podocyte injury in renal tissue was detected by immunofluorescence staining for podocin. To further explore the underlying mechanism, serum Angptl4 levels were measured, and Angptl4, integrin β3, fibronectin, and podocin levels in renal tissue were analysed by Western blotting. In vitro, podocytes are stimulated with high glucose and then treated with UCMSCs, and podocyte activity and the expression of synaptopodin, Angptl4, and integrin β3 were observed. UCMSC significantly improve renal function, pathological injury, and podocyte injury in the ZDF (FA/FA) rats. Western blot revealed increased expression of Angptl4, integrin β3, and fibronectin in renal tissues of the DN group, and UCMSC treatment significantly downregulated those proteins. However, UCMSC showed no effects on serum Angptl4 concentration. Podocin expression in renal tissues was significantly restored by UCMSC treatment. In vitro, podocyte activity was decreased after high glucose stimulation and improved by UCMSC treatment. UCMSC restored the expression of synaptopodin, and Angptl4 and downstream integrin β3 were also inhibited. Our study suggested that UCMSC therapy could improve renal function and renal pathological changes in ZDF (FA/FA) rats. In addition, inhibition of the Angptl4/integrin β3 pathway is the potential mechanism by which UCMSC attenuates podocyte injury in the DN model.

Using guideline-directed medical therapies to improve kidney and cardiovascular outcomes in patients with chronic kidney disease

PURPOSE

An estimated 37 million people currently live with chronic kidney disease in the US, which places them at increased risk for kidney disease progression, cardiovascular disease, and mortality. This review discusses current standard-of-care management of patients with chronic kidney disease, identifies key gaps in care, and briefly highlights how pharmacists can address gaps in care as members of the multidisciplinary care team.

SUMMARY

Recent advances in guideline-directed medical therapies for patients with chronic kidney disease, including agents from the sodium-glucose cotransporter, glucagon-like peptide-1 receptor agonist, and nonsteroidal mineralocorticoid receptor antagonist classes, can dramatically improve cardiovascular-kidney-metabolic care and outcomes. Unfortunately, gaps in screening, diagnosis, and implementation of recommended therapies persist. Team-based models of care-inclusive of the person with chronic kidney disease-have the potential to significantly improve care and outcomes for people with chronic kidney disease by addressing current gaps in care.

CONCLUSION

As members of the multidisciplinary care team, pharmacists can play a critical role in addressing current gaps in care, including optimized use of guideline-directed medical therapies, in patients with chronic kidney disease.

Uncoupling protein 1-mediated protective effects of β3-adrenergic receptor agonist on kidney fibrosis via promoting adipose tissue browning in diabetic mice

BACKGROUND

Diabetes mellitus (DM) is a global health concern. Diabetic kidney disease (DKD) is a prevalent severe complication of DM and therapy is urgently needed. Adipose tissue (AT) plays a crucial role in the energy mediation through glucolipid metabolism. Mirabegron is a specific β3-adrenergic receptor agonist, which can activate thermogenesis in adipocytes, improve energy consumption, and increase insulin sensitivity and glucose tolerance. Therefore, mirabegron may play a role in DKD pathogenesis. However, its effects and precise mechanisms remain unclear.

METHODS

A DKD mouse model based on type 2 DM (T2DM) was constructed and treated with mirabegron. Mice with AT surgically removed and mice with uncoupling protein 1 (Ucp1) knockout were used to confirm whether thermogenesis induced by mirabegron was the key process.

RESULTS

Mirabegron promoted AT browning in DKD mice. Mirabegron increased insulin sensitivity, promoted glucolipid metabolism, reduced inflammatory factor levels in kidney tissue, and improved renal function and fibrosis in DKD mice. Notably, all of these benefits disappeared in AT-removed DKD mice or in Ucp1 knockout DKD mice.

CONCLUSIONS

Mirabegron protects against kidney fibrosis in DM mice by activating AT thermogenesis via the UCP1 pathway. Thus, mirabegron may provide a promising potential option for DKD therapy.

Finerenone Across the Spectrum of Kidney Risk in Heart Failure: The FINEARTS-HF Trial

BACKGROUND

Estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio are complementary domains of kidney disease staging and independently associated with heart failure (HF) progression.

OBJECTIVES

The purpose of this study was to evaluate whether the efficacy and safety of finerenone varies according to kidney risk among patients with HF with mildly reduced or preserved ejection fraction.

METHODS

In this prespecified analysis of FINEARTS-HF (Finerenone Trial to Investigate Efficacy and Safety Superior to Placebo in Patients with Heart Failure), clinical outcomes and treatment effects of finerenone on the primary endpoint (cardiovascular death and total [first and recurrent] HF events) and key secondary endpoints were evaluated according to baseline KDIGO (Kidney Disease: Improving Global Outcomes) risk category (low, moderately increased, and high or very high). Key exclusion criteria in FINEARTS-HF were eGFR <25 mL/min/1.73 m2 or serum potassium >5.0 mmol/L.

RESULTS

Overall, 5,797 (97%) FINEARTS-HF participants had classifiable KDIGO risk category at baseline, of whom 2,022 (35%), 1,688 (29%), and 2,087 (36%) were low, moderate, and high/very high risk, respectively. Over a median follow-up of 2.7 years, higher kidney risk was associated with a higher rate of primary outcome events, with similar findings for other key endpoints, including the composite kidney outcome, new-onset atrial fibrillation, and vascular events. Benefits of finerenone vs placebo on the primary endpoint (Pinteraction = 0.24) and Kansas City Cardiomyopathy Questionnaire-Total Symptom Score at 12 months (Pinteraction = 0.36) were consistent irrespective of baseline kidney risk category. Participants with higher kidney risk experienced greater reductions in urine albumin-to-creatinine ratio after 6 months (Pinteraction = 0.031), without differences in eGFR slope. Risks of safety events, including hyperkalemia, with finerenone vs placebo were not enhanced among participants with higher kidney risk.

CONCLUSIONS

Finerenone appears to consistently improve clinical outcomes, HF-related health status, and albuminuria across a broad spectrum of kidney risk in patients with HF with mildly reduced or preserved ejection fraction. (Study to Evaluate the Efficacy [Effect on Disease] and Safety of Finerenone on Morbidity [Events Indicating Disease Worsening] and Mortality [Death Rate] in Participants With Heart Failure and Left Ventricular Ejection Fraction [Proportion of Blood Expelled Per Heart Stroke] Greater or Equal to 40% [FINEARTS-HF]; NCT04435626).

Oxybaphus himalaicus alleviates diabetic kidney disease by suppressing the lipid metabolism and inflammation via PPARα signaling

Diabetic kidney disease (DKD) is a common complication in patients with diabetes, and glycolipid metabolism disorders are an important cause of DKD. The root of Oxybaphus himalaicus (Edgew.) Heimerl is a traditional Tibetan medicine commonly used to treat kidney-related diseases. Nevertheless, contemporary pharmacological investigations into O. himalaicus, especially those associated with the treatment of renal disorders, remain scarce. The objective of this research was to explore the pharmaceutical impacts and mechanisms of action of O. himalaicus in the treatment of DKD. The active fraction and potential pharmacological effects of O. himalaicus were determined through network pharmacology. Then, in vivo and in vitro efficacy and mechanism studies were conducted through streptozotocin-induced DKD mice and high glucose-induced HK-2 cells. Network pharmacology research speculated the ethyl acetate (EA) fraction as the main active component of O. himalaicus for treating DKD. In vivo and in vitro experiments showed that EA reduces renal lipotoxicity by upregulating PPARα pathway proteins, enhancing fatty acid oxidation (FAO), and downregulating inflammatory factors such as TNF-α and IL-6. Molecular docking studies revealed that the active components of EA with a high affinity for PPARα are mainly rotenoid compounds. EA mitigates DKD through the activation of PPARα, which serves to augment FAO, abate lipid accumulation, and impede the expression of inflammatory factors. Among these, rotenoids may be the main active components that exert pharmacological effects.

Discussion on the treatment of diabetic kidney disease based on the "gut-fat-kidney" axis

Diabetic kidney disease is the main cause of end-stage renal disease, and its prevention and treatment are still a major clinical problem. The human intestine has a complex flora of hundreds of millions of microorganisms, and intestinal microorganisms, and their derivatives are closely related to renal inflammatory response, immune response, and material metabolism. Brown adipose tissue is the main part of adaptive thermogenesis. Recent studies have shown that activating brown fat by regulating intestinal flora has good curative effects in diabetic kidney disease-related diseases. As an emerging medical concept, the "gut-fat-kidney" axis has received increasing attention in diabetic kidney disease and related diseases. However, the specific mechanism involved needs further study. A new theoretical basis for the prevention and treatment of diabetic kidney disease is presented in this article, based on the "gut-fat-kidney" axis.

Trends and Disparities in the Burden of Chronic Kidney Disease due to Type 2 Diabetes in China From 1990 to 2021: A Population-Based Study

BACKGROUND

This study analyzes the trends in the burden of chronic kidney disease due to type 2 diabetes (CKD-T2D) in China from 1990 to 2021, evaluates variations in risk factors, and projects the disease burden through 2036.

METHOD

Estimates of prevalence, incidence, mortality, and disability-adjusted life years (DALYs) for CKD-T2D were retrieved along with their 95% uncertainty intervals (UIs). Age-period-cohort analysis was used to assess burden trends from 1990 to 2021, identify risk factor population attributable fractions (PAFs), and project the burden through 2036.

RESULTS

In 2021, there were 20 911 520 CKD-T2D cases in China, with an age-standardized prevalence rate (ASPR) of 1053.92 per 100 000, an incidence rate (ASIR) of 23.07, an age-standardized mortality rate (ASMR) of 5.72, and an age-standardized DALY rate (ASDR) of 122.15. Although the overall burden showed a slow decline from 1990 to 2021, incidence continued to rise. The 2021 data revealed a marked age effect, with the burden rising with age. Period effects also contributed to an increased risk, with metabolic risk factors such as high fasting plasma glucose and BMI contributing the most. Projections suggest a decline in mortality and DALYs by 2036, while incidence will keep increasing.

CONCLUSION

Despite declines in ASMR and ASDR, CKD-T2D incidence and cases continue to rise, especially among males and the elderly. This increasing burden is driven by aging and metabolic risk factors. Early screening, education, and risk management are essential for addressing CKD-T2D in China.

Huaiqihuang (HQH) protects podocytes from high glucose-induced apoptosis and inflammation response by regulating PI3K/AKT/mTOR pathway

Diabetic kidney disease (DKD) is one of the common microvascular complications of diabetes, and there are still lack of effective treatments. Huaiqihuang (HQH) is a kind of traditional Chinese medicine mixed preparation, which is mainly made of Trametes robiniophila Murr, Fructus Lycii, and Polygonatum sibiricumhas. It has been shown to be effective in the treatment of DKD, but the specific mechanism has not been fully elucidated. Our results showed that HQH increased the protein expressions of synaptopodin, podocin, WT-1, and Bcl-2, decreased the protein expressions of Bax and cleaved-casepase-3, and activated the NF-ĸB and PI3K/AKT/mTOR pathway in MPC5 cells exposed to high-glucose (HG). Real-time PCR results showed that HQH reduced the mRNA expression of TNF-α, IL-1β, MCP-1, and IL-6. In conclusion, our results showed that HQH may attenuate podocyte injury by inhibiting MPC5 cell apoptosis induced by HG and NF-κB-mediated inflammation response through activation of the PI3K/AKT/mTOR pathway.

Dietary therapy to halt the progression of diabetes to diabetic kidney disease

Diabetic Kidney Disease (DKD) is a common and serious complication of diabetes, particularly Type 2 Diabetes Mellitus (T2DM), which significantly contributes to patient morbidity and mortality. The limitations of traditional treatments like ACE inhibitors and ARBs in managing DKD progression highlight the need for innovative therapeutic strategies. This review examines the impact of various dietary patterns, such as the Mediterranean diet, ketogenic diet, intermittent fasting, DASH diet, and vegetarian diet, on the management of DKD. Evidence suggests these diets can halt the progression of DKD, although further research is needed to confirm their long-term effectiveness and safety. Personalized dietary approaches tailored to individual needs may enhance outcomes for DKD patients.

Association of diabetic nephropathy with lipid metabolism: a Mendelian randomization study

OBJECTIVE

Patients with diabetic nephropathy (DN) often present with lipid profile abnormalities. While associations between these parameters and DN have been suggested, confounding factors obscure causal relationships. This study employed bidirectional Mendelian randomization (MR) to explore these links.

METHODS

Using genome-wide association study (GWAS) data, the primary analysis used the inverse-variance weighted (IVW) method, which was supported by MR-Egger regression and a weighted median estimator (WME). Sensitivity analyses, including heterogeneity, pleiotropy tests, leave-one-out, and reverse causality analyses, were conducted.

RESULTS

The IVW model revealed the following: (1) causal relationships between triglycerides (TG) (OR: 1.5807, 95% CI: 1.2578-1.9865, P = 0.0001), high-density lipoprotein cholesterol (HDL-C) (OR: 0.7342, 95% CI: 0.5729-0.9409, P = 0.0146), and apolipoprotein A1 (ApoA1) (OR: 0.6506, 95% CI: 0.5190-0.8156, P = 0.0002) and DN; (2) causal relationships between TG (OR: 1.0607, 95% CI: 1.0143-1.1093, P = 0.0098), HDL-C (OR: 0.9453, 95% CI: 0.9053-1.9871, P = 0.0109), and apolipoprotein B (ApoB) (OR: 1.0672, 95% CI: 0.0070-1.1310, P = 0.0280) and the urinary albumin-creatinine ratio (UACR); (3) no causal relationship between total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), ApoB and DN, or between TC, LDL-C, ApoA1 and UACR; (4) none of the results showed reverse causality.

CONCLUSION

TG is a risk factor for DN and UACR; HDL-C is protective for both; ApoA1 protects against DN; and ApoB is a risk factor for UACR. To further explore the underlying mechanisms between TG, HDL-C, ApoA1, ApoB, and their associations with DN and UACR, and to provide reference for the selection of lipid management and treatment strategies for clinical DN patients. This study demonstrated that causal relationships between TG, HDL-C, and ApoA1 with DN and between TG, HDL-C, and ApoB with the UACR.

Effects of dietary oxidative balance score on diabetic nephropathy and renal function: insights from retrospective and cross-sectional studies

Background

The relationship between dietary oxidative balance score (DOBS) and diabetes-related renal events remains unclear.

Methods

In this study, the associations between serum micronutrients and diabetic nephropathy (DN) in participants matched by propensity score (PSM) were retrospectively analyzed. And next, a cross-sectional analysis was performed with the National Health and Nutritional Examination Survey (NHANES) database. Weighted multivariate adjusted logistic regression models, dose-response curves, subgroup analysis, and mediation analysis were the main methods of this study. Finally, sensitivity analyses were performed by PSM and multiple imputation (MI).

Results

Retrospective findings suggest that single antioxidants may not be representative of an individual's overall antioxidant levels. The results of the cross-sectional study indicated that the higher the DOBS, the greater the beneficial effects on DN [Q4 vs. Q1: OR (95% CI): 0.78 (0.63, 0.96), p for trend = 0.008] and renal function in DN [Q4 vs. Q1: β (95% CI): 5.395 (1.590, 9.199), p for trend = 0.004]. The above correlations were linear negative correlation (p for nonlinear = 0.989) and linear positive correlation (p for nonlinear = 0.593) respectively. Chronic inflammation mediated the above associations to some extent. The results of sensitivity analysis were consistent with the original analysis.

Conclusion

Higher dietary antioxidant exposure has a positive effect on DN and renal function in DN, mediated partially by chronic inflammation.

Important regulatory role of mitophagy in diabetic microvascular complications

Microvascular complications of diabetes pose a significant threat to global health, mainly including diabetic kidney disease (DKD), diabetic retinopathy (DR), diabetic peripheral neuropathy (DPN), and diabetic cardiomyopathy (DCM), which can ultimately lead to kidney failure, blindness, disability, and heart failure. With the increasing prevalence of diabetes, the search for new therapeutic targets for diabetic microvascular complications is imminent. Mitophagy is a widespread and strictly maintained process of self-renewal and energy metabolism that plays an important role in reducing inflammatory responses, inhibiting reactive oxygen species accumulation, and maintaining cellular energy metabolism. Hyperglycemia results in impaired mitophagy, which leads to mitochondrial dysfunction and ultimately exacerbates disease progression. This article summarizes the relevant molecular mechanisms of mitophagy and reviews the current status of research on regulating mitophagy as a potential treatment for diabetic microvascular complications, attempting to give new angles on the treatment of diabetic microvascular complications.

Protective effect of orientin on diabetic nephropathy in rat models of high-fat diet and streptozotocin-induced diabetes

Diabetic nephropathy (DN) represents the primary cause of chronic kidney disease (CKD) worldwide. Orientin is a natural bioactive flavonoid with profound immunomodulatory, anti-inflammatory, and antioxidative effects. This study aimed to investigate the nephroprotective effect of orientin on rat prototypes of high-fat diet (HFD) and streptozotocin (STZ)-induced DN. 75 male rats were divided into 5 groups of 15 rats each. Rats were fed a HFD for 4 weeks, injected with a single dose of STZ 30 mg/kg, and continued on HFD for 15 weeks. Orientin was administered daily at 40 mg/kg for 15 weeks. The diabetic group reported substantially greater fasting blood glucose, HbA1c, and renal function measures than normal controls, as well as notable kidney histological abnormalities such as interstitial inflammation, glomerular shrinkage, and tubular necrosis. Additionally, the diabetic group showed dramatically greater amounts of IL-1β, IL-6, TNF-α, TGF-β1, MDA, and a much lower level of GSH than the control group. However, orientin had no effect on the glycaemic parameters, but it dramatically reduced blood creatinine levels, prevented the development of histopathological irregularities, and minimized the renal concentrations of inflammatory and oxidative markers. Orientin may be a promising natural medication for improving diabetic nephropathy thanks to its robust anti-inflammatory and anti-proliferative properties.

Targeting the NF-κB p65-MMP28 axis: Wogonoside as a novel therapeutic agent for attenuating podocyte injury in diabetic nephropathy

BACKGROUND

Although recent progress provides mechanistic insights into diabetic nephropathy (DN), effective treatments remain scarce. DN, characterized by proteinuria and a progressive decline in renal function, primarily arises from podocyte injury, which impairs the glomerular filtration barrier. Wogonoside, a bioactive compound from the traditional Chinese herb Scutellaria baicalensis, has not been explored for its role in DN.

PURPOSE

This study aimed to investigate the therapeutic effects of wogonoside on podocyte injury in DN and its molecular mechanisms.

METHODS

The effects of wogonoside were examined using HFD/STZ-induced DN mouse models and high glucose (HG)-induced MPC-5 cells. Oxidative stress and inflammation markers were analyzed via Western blot and RT-qPCR. Wogonoside targets were identified through DARTS-MS and validated by SPR, molecular docking, alanine scanning, and CETSA. RNA-Seq analysis was employed to identify downstream targets, and the p65-MMP28 axis was explored through p65 knockdown and overexpression studies. The regulatory effect of p65 on Mmp28 was confirmed through dual-luciferase reporter assays and ChIP-qPCR.

RESULTS

Wogonoside treatment significantly reduced oxidative stress and inflammation in vivo and in vitro. Mechanistic studies identified p65 as a direct target of wogonoside, with SPR confirming a strong binding affinity (KD = 25.05 μM). Molecular docking and alanine scanning identified LYS221 as a critical binding site, which was further supported by CETSA using the p65 K221A mutant. RNA-Seq analysis revealed Mmp28 as a downstream effector of p65 involved in HG-induced podocyte injury. Functional studies demonstrated that wogonoside's protective effects on antioxidant and inflammatory pathways are mediated via the p65-MMP28 axis. Dual-luciferase reporter assays revealed that p65 regulates Mmp28 transcription, and ChIP-qPCR confirmed its direct promoter binding.

CONCLUSIONS

This study highlights wogonoside as a promising candidate for the treatment of podocyte injury in DN by targeting the NF-κB p65-MMP28 signaling axis. These findings provide novel insights into wogonoside's therapeutic potential and its molecular mechanisms, paving the way for its further development as a DN intervention.

Investigation of the role and mechanism of dapagliflozin in mitigating renal injury in rats afflicted with diabetic kidney disease

The etiology of diabetic kidney disease (DKD) is multifaceted, with hyperglycemia, inflammation, oxidative stress, and fibrosis recognized as key contributors to renal damage in individuals with DKD. Clinical evidence suggests that dapagliflozin not only reduces blood glucose levels but also demonstrates superior efficacy in ameliorating pancreatic islet cell injury while preserving cardiac and renal function. However, the precise underlying mechanism has been poorly elucidated in the current literature. In this study, a DKD rat model was established by administering a single intraperitoneal injection of streptozotocin (STZ) to investigate the renoprotective properties of dapagliflozin and its underlying mechanisms. The findings of this study indicate that dapagliflozin enhanced pancreatic islet cell function, lowered blood glucose levels, and significantly reduced biochemical markers and renal pathological damage in DKD rats. Dapagliflozin also exerted anti-inflammatory, antioxidant, and antifibrotic effects by inhibiting the activation of the p38 MAPK/NF-κB pathway, enhancing the activity of the SIRT1/Akt/GSK-3β/Nrf2/HO-1 signaling pathway, and inhibiting the over-activation of the TGF-β1/Smad2/3 signaling pathway. These effects led to a reduction in renal injury and improved renal function in DKD rats.

Mitochondria-dependent apoptosis was involved in the alleviation of Jujuboside A on diabetic kidney disease-associated renal tubular injury via YY1/PGC-1α signaling

BACKGROUND

Renal tubular injury was a significant pathological change of diabetic kidney disease (DKD), and the amelioration of renal tubular injury through mitochondrial function was an important treatment strategy of DKD. Our previous study had revealed that Jujuboside A (Ju A), the main active substance isolated from Semen Ziziphi Spinosae (SZS), could restore renal function of diabetic mice. However, its protective mechanism against DKD remains unclear.

PURPOSE

To investigate the effects and the mechanism of Ju A against DKD-associated renal tubular injury.

STUDY DESIGN AND METHODS

The anti-apoptotic effect of Ju A and its protection effect on mitochondria dysfunction of renal tubular epithelial cells (RTECs) were examined in high glucose (HG)-cultured HK-2 cells, and in db/db mice. Subsequently, Network Pharmacology analysis, molecular docking, luciferase assay, chromatin immunoprecipitation (ChIP), Yin Yang 1 (YY1) overexpression lentiviral vector and peroxisome proliferator-activated receptor-γ coactlvator-1α (PGC-1α) specific agonist ZLN005 were all used to identify the protective mechanism of Ju A towards DKD-associated mitochondrial dysfunction of RTECs.

RESULTS

Ju A inhibited RTECs apoptosis and ameliorated mitochondria dysfunction of RTECs of diabetic mice, and HG-cultured HK-2 cells. YY1 was the potential target of Ju A against DKD-related mitochondrial dysfunction, and the down-regulation of YY1 induced by Ju A increased PGC-1α promoter activity, leading to the restored mitochondrial function of HG-treated HK-2 cells. Renal tubule specific overexpression of YY1 intercepted the renal protective effect of Ju A on diabetic mice via blocking PGC-1α-mediated restoration of mitochondrial function of RTECs. The in-depth mechanism research revealed that the protective effect of Ju A towards DKD-associated renal tubular injury was linked to the restored mitochondrial function through YY1/PGC-1α signaling, resulting in the inhibited apoptosis of RTECs in diabetic condition via inactivating CytC-mediated Caspase9/Caspase3 signaling.

CONCLUSION

Ju A through the inhibition of mitochondria-dependent apoptosis alleviated DKD-associated renal tubular injury via YY1/PGC-1α signaling.

Association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and cardiovascular disease mortality in patients with type 2 diabetes mellitus and diabetic kidney disease

Purpose

Non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) represents an essential lipid index and is closely related to the occurrence and development of diabetes and cardiovascular diseases (CVDs). Therefore, this study is intended to further investigate the association between the NHHR index and the mortality rate of CVDs in patients with type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD).

Methods

The research sample was selected from the NHANES (National Health and Nutrition Examination Survey) database, and 5136 individuals were categorized based on quartiles of the NHHR index. Restricted cubic plots and COX regression models were utilized to examine the thresholds and patterns of the NHHR index in relation to the risk of CVDs mortality among T2DM patients as well as those with DKD. Subgroup analyses and p-values were used to evaluate interactions between different variables.

Results

The NHHR index shows a nonlinear association with cardiovascular mortality in two patient groups, following an L-shaped pattern. In individuals with T2DM, a lower NHHR index (<1.68) correlates with an increased risk of death, demonstrating a 72.8% reduction in mortality risk for each unit increase in NHHR below this threshold. Similarly, among patients with DKD, a lower NHHR index (<1.82) is associated with heightened cardiovascular mortality risk, indicating a 48.2% reduction in death risk for each unit increase in NHHR beneath the specified threshold. In patients diagnosed with T2DM, the third quartile of the NHHR index was significantly linked to reduced mortality risk; the association remained consistent even when additional variables were considered [Hazard Ratio (HR), 0.82; 95% Confidence Interval (CI) (0.69-0.97); P=0.019]. Among patients with DKD, cardiovascular mortality was notably higher in the third and fourth quartiles of the NHHR index [Quartile3 HR, 1.57; 95% CI (1.10-2.24), P=0.013; Quartile4 HR, 2.04; 95% CI (1.28-3.26), P=0.003].

Conclusions

The NHHR is below 1.68, and an increase in the NHHR index is associated with a reduced risk of CVD mortality in patients with T2DM. Similarly, when the NHHR falls below 1.82, an elevation in the NHHR index correlates with a decreased risk of CVD mortality in patients with DKD.

MTDH inhibits CrAT to promote mitochondrial damage in palmitic acid-induced renal tubular cells

PURPOSE

Mitochondrial dysfunction leading to impaired energy metabolism has been recognized as a pivotal factor contributing to renal tubular epithelial cells (RTECs) damage in the context of dyslipidemia conditions in diabetic kidney disease (DKD). The primary objective of this study is to elucidate the role and underlying mechanism of the proto-oncogene Metadherin (MTDH) in mediating mitochondrial damage within this specific pathological context in vitro.

METHODS

The expression of MTDH in RTECs was modulated by transfecting small interfering RNA and plasmid, while palmitic acid (PA) was employed to simulate diabetic lipid metabolism disorder. Mitochondrial damage was evaluated by examining various parameters including mitochondrial morphology, membrane potential, reactive oxygen species (ROS) production, adenosine triphosphate (ATP) production, as well as morphological and structural alterations. Additionally, Carnitine acetyltransferase (CrAT) expression was assessed using Western blotting and quantitative real-time polymerase chain reaction, and CrAT activity was quantified.

RESULT

MTDH expression was upregulated in PA-induced RTECs, while CrAT expression and activity were inhibited. Downregulation of MTDH mitigated PA-induced mitochondrial damage, as demonstrated by the preservation of mitochondrial membrane potential, reduction in mitochondrial ROS production, prevention of ATP depletion, and maintenance of mitochondrial structure. This was accompanied by an upregulation in CrAT expression and activity. Conversely, overexpression of MTDH exacerbated mitochondrial dysfunction by impairing membrane potential, augmenting mitochondrial ROS production, inhibiting ATP synthesis, and suppressing CrAT expression and activity.

CONCLUSION

In the context of dyslipidemia conditions, MTDH is upregulated and suppresses the expression and activity of CrAT in RTECs, thereby inducing mitochondrial dysfunction and perturbing energy metabolism. These alterations exacerbate the injury to RTECs, consequently promoting the progression of DKD.

Uncovering the mechanism of Huangkui capsule in the treatment of diabetic kidney disease based on network pharmacology and experimental validation

Diabetic kidney disease (DKD) is a main complication of diabetes mellitus. experimental in vitro validation and Network pharmacology were used in this study to explore the potential mechanism of Huangkui capsules (HKC) in treating DKD. First, we used CCK8 to analyze the optimal drug concentration of HKC. Next, we used flow cytometry, ELISA, Scratch test, and immunofluorescence to examine the apoptosis, oxidative stress, inflammatory factors, and fibrotic factors (FN and α-SMA) expression in HK-2 cells. Thereafter, in order to determine the potential molecular mechanisms underlying the therapeutic effect of HKC in DKD. Compounds contained in HKC were explored by UPLC-Q-TOF-MS/MS. SwissTargetPrediction was utilized for predicting potential gene targets of these compounds. OMIM, DisGeNet and GeneCards databases were employed to identify DKD-related genes. Meanwhile, the association of compounds with DKD genes was examined by protein-protein interaction, GO and KEGG analysis. Finally, molecular docking and molecular dynamics simulation were adopted for further validation. The results showed that HKC had 40 active ingredients, 1051 possible gene targets, and 133 DKD-HKC intersection genes. IL6, TNF, GAPDH, AKT1, PPARG, and TP53 were candidate hub genes by which HKC exerted its anti-DKD function based on molecular docking, molecular dynamics simulation and experimental results. To conclude, this study sheds more lights on the possible pharmacological activities of HKC in DKD and a foundation for further clinical application.

Advances in kidney disease: pathogenesis and therapeutic targets

Chronic kidney disease (CKD) is a global public health issue characterized by progressive loss of kidney function, of which end-stage kidney disease (ESKD) is the last stage. The global increase in the prevalence of CKD is linked to the increasing prevalence of traditional risk factors, including obesity, hypertension, and diabetes mellitus, as well as metabolic factors, particularly insulin resistance, dyslipidemia, and hyperuricemia. Mortality and comorbidities, such as cardiovascular complications, rise steadily as kidney function deteriorates. Patients who progress to ESKD require long-term kidney replacement therapy, such as transplantation or hemodialysis/peritoneal dialysis. It is currently understood that a crucial aspect of CKD involves persistent, low-grade inflammation. In addition, increased oxidative and metabolic stress, endothelial dysfunction, vascular calcification from poor calcium and phosphate metabolism, and difficulties with coagulation are some of the complex molecular pathways underlying CKD-related and ESKD-related issues. Novel mechanisms, such as microbiome dysbiosis and apolipoprotein L1 gene mutation, have improved our understanding of kidney disease mechanisms. High kidney disease risk of Africa has been linked to APOL1 high-risk alleles. The 3-fold increased risk of ESKD in African Americans compared to European Americans is currently mainly attributed to variants in the APOL1 gene in the chromosome 22q12 locus. Additionally, the role of new therapies such as SGLT2 inhibitors, mineralocorticoid receptor antagonists, and APOL1 channel function inhibitors offers new therapeutic targets in slowing down the progression of chronic kidney disease. This review describes recent molecular mechanisms underlying CKD and emerging therapeutic targets.

New insights in the treatment of DKD: recent advances and future prospects

Diabetic kidney disease (DKD) represents the predominant and severe microvascular complication associated with diabetes, frequently culminating in End-Stage Kidney Disease (ESKD). The escalating prevalence of diabetes has correspondingly led to a rise in DKD incidence, imposing significant challenges on both individuals and society. The etiology of DKD is multifaceted and remains devoid of definitive therapeutic interventions. This article examines the pharmacological actions and mechanisms of different drugs used for the prevention and treatment of DKD that are currently in clinical use or undergoing development. The goal is to offer insights for early intervention based on therapeutic combinations to potentially slow kidney disease progression.

Research progress of hypoxia-inducible factor-1α and zinc in the mechanism of diabetic kidney disease

Diabetic kidney disease is one of the common complications in diabetic patients and has gradually become an important pathogenic factor in chronic kidney disease. Therefore, studying the mechanisms of its occurrence and development is of great significance for the prevention and treatment of diabetic kidney disease. Some researchers have pointed out that there is a phenomenon of hypoxia in diabetic kidney tissue and believe that hypoxia-inducible factor-1α is closely related to the occurrence and progression of diabetic kidney disease. Additionally, the homeostasis of zinc plays a key role in the body's adaptation to hypoxic environments. However, the specific relationship among these three factors remains unclear. This article provides a detailed review of the multiple roles of hypoxia-inducible factor-1α in the pathogenesis of diabetic kidney disease, including: regulating angiogenesis, increasing the expression of erythropoietin, modulating oxidative stress through the PI3K/AKT and HIF-1α/HO-1 pathways, promoting inflammatory cell infiltration and the release of inflammatory factors to induce inflammatory responses, facilitating epithelial-mesenchymal transition, pathological angiogenesis, and promoting the release of fibrotic factors, ultimately leading to renal fibrosis. Furthermore, HIF-1α also participates in the occurrence and development of diabetic kidney disease through mechanisms such as regulating apoptosis, inducing mitochondrial autophagy, and vascular calcification. At the same time, this article clarifies the regulatory role of the trace element zinc on hypoxia-inducible factor-1α in diabetic kidney disease. This article provides references and insights for further research on the pathogenesis and progression of diabetic kidney disease.

Combination therapy: an upcoming paradigm to improve kidney and cardiovascular outcomes in chronic kidney disease

In this article the authors review recent advances in the treatment of chronic kidney disease (CKD) with diabetes, and summarize evidence supporting combination therapy approaches to improve patient outcomes. Driven by the global rise in diabetes, the worldwide burden of CKD has nearly doubled since the 1990s. People with CKD have notably increased risks for premature cardiovascular disease (heart and blood vessels disease), kidney failure and death. CKD, diabetes, obesity and cardiovascular disease are closely interrelated and share common risk factors. These health conditions therefore comprise what is now known as cardiovascular-kidney-metabolic (CKM) syndrome. Recently approved medications, including sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs) and the non-steroidal mineralocorticoid receptor antagonist (ns-MRA) finerenone, represent agents capable of reducing metabolic, kidney and cardiovascular risk through complementary mechanisms of action. Current evidence supports use of these therapies in combination. Besides providing additive protective effects, combination therapy may also help reduce side effects. For instance, using an SGLT2 inhibitor in combination with finerenone helps decrease the risk for high potassium levels. Through the multipronged approach, combination therapy allows tailoring treatment for the individual patient characteristics and needs. Several planned and ongoing clinical trials continue to study the benefits of combination therapy in people with CKM syndrome. With building evidence supporting the use of combination therapy, it is crucial to raise awareness of the importance of this treatment approach and develop processes to incorporate new therapies into every day practice to support optimal care and improved outcomes.

ABSTRACT

The global burden of chronic kidney disease (CKD) increased by nearly 90% in the period spanning 1990 to 2016, mostly attributed to an increase in the prevalence of CKD in diabetes. People living with CKD have an elevated lifetime risk for cardiovascular disease (CVD) when compared with the general population, with risk increasing in parallel with albuminuria and kidney function decline. Metabolic disease, CKD and CVD share common risk factors including neurohumoral activation, systemic inflammation and oxidative stress, thus prompting the introduction of a broader construct of cardiovascular-kidney-metabolic (CKM) syndrome. An important rationale for the introduction of this concept are recent and ongoing therapeutic advancements fundamentally changing CKM management. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs) and the non-steroidal mineralocorticoid receptor antagonist (ns-MRA) finerenone have shifted the therapeutic paradigm for patients with CKD and have emerged in rapid succession as cornerstones of guideline-directed medical therapy (GDMT). Recently completed clinical trials of aldosterone synthase inhibitors and endothelin receptor antagonists have additionally reported additive antiproteinuric effects on the background of renin-angiotensin system and SGLT2 inhibition, with acceptable safety profiles. The sum of current evidence from both preclinical and clinical studies support combination therapy in the setting of CKD to achieve additive and potentially synergistic kidney and heart protection by addressing metabolic, hemodynamic, and pro-inflammatory and pro-fibrotic mechanistic pathways. This narrative review will discuss available evidence supporting combination GDMT in CKD with diabetes and additionally discuss ongoing and future trials evaluating the efficacy and safety of combination therapies for CKD with or without diabetes.

Neddylation of RhoA impairs its protein degradation and promotes renal interstitial fibrosis progression in diabetic nephropathy

Diabetic nephropathy (DN) is a common and serious complication of diabetes, characterized by chronic fibro-inflammatory processes with an unclear pathogenesis. Renal fibrosis plays a significant role in the development and progression of DN. While recent research suggests that the neddylation pathway may influence fibrotic processes, its specific dysregulation in DN and the underlying mechanisms remain largely unexplored. This study identified the neddylation of RhoA as a novel post-translational modification that regulates its expression and promotes renal fibrosis in DN. We here demonstrated that two key components of the neddylation pathway-NEDD8-activating enzyme E1 subunit 1 (NAE1) and NEDD8-are significantly upregulated in human chronic kidney disease (CKD) specimens compared to healthy kidneys, implicating neddylation in CKD-associated fibrosis. Our findings further revealed that both pharmacological inhibition of neddylation using MLN4924 and genetic knockdown of NAE1 mitigate renal fibrosis in mouse models of streptozotocin-induced diabetes and unilateral ureteral obstruction (UUO). Immunoprecipitation-mass spectrometry (IP-MS) and subsequent function assays demonstrated a direct interaction between RhoA and NEDD8. Importantly, neddylation inhibition reduced RhoA protein expression, highlighting a potential therapeutic target. Additionally, a positive correlation was noted between elevated NEDD8 mRNA levels and RhoA mRNA expression in human CKD specimens. RhoA overexpression counteracted the antifibrotic effects of neddylation inhibition, underscoring its critical role in fibrosis progression. Mechanistically, we unveiled that neddylation enhances RhoA protein stability by inhibiting its ubiquitination-mediated degradation, which subsequently activates the ERK1/2 pathway. Collectively, this study provides novel insights into NAE1-dependent RhoA neddylation as a key contributor to renal fibrosis in DN. The NAE1 protein mediates RhoA protein hyper-neddylation and subsequent stabilization of the RhoA protein, which, in turn, contributes to the development of renal fibrosis and inflammation through an ERK1/2-dependent mechanism. Consequently, targeting neddylation inhibition represents a viable therapeutic approach for the treatment of renal fibrosis in DN.

TRAIL induces podocyte PANoptosis via death receptor 5 in diabetic kidney disease

Podocytes can undergo PANoptosis (apoptosis, pyroptosis, and necroptosis). Diabetic kidney disease (DKD) is the leading cause of kidney failure, and podocyte loss is a major event leading to the progression of DKD. Here, we compared single cell RNA sequencing (scRNA-seq) data between three normal and three DKD human kidney samples and found a significant increase of TNFSF10 and TNFRSF10B expression in podocytes of patients with DKD. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), coded by TNFSF10, belongs to the TNF superfamily members and TNFRSF10B codes for death receptor 5 (DR5). We confirmed that expression of TRAIL and DR5 increased in podocytes of patients with DKD and correlated with the severity of DKD. In vitro, TNF-α stimulated TRAIL and DR5 expression in cultured human podocytes. Silence of TRAIL or DR5 by small interfering RNA alleviated TNF-α-stimulated podocytes PANoptosis, while overexpression of TRAIL, treatment with recombinant human TRAIL (rh-TRAIL) or the DR5 activator (Bioymifi) enhanced podocytes PANoptosis. In vivo, podocyte-specific deletion of TNFSF10 or TNFRSF10B alleviated podocyte and glomerular injury in high fat diet and streptozotocin-induced obese diabetic mice and was associated with decreased podocyte PANoptosis. Conversely, the induction of TNFSF10 overexpression specifically in podocytes exacerbated albuminuria and kidney injury in diabetic mice with increased podocyte PANoptosis. Additionally, administration of soluble DR5-Fc, an inhibitor of DR5, resulted in a marked reduction in albuminuria and glomerular injury in BTBR ob/ob mice. Our findings suggest a critical autocrine role of TRAIL/DR5 in inducing podocyte injury in DKD via activation of PANoptosis.

Complement anaphylatoxins: Potential therapeutic target for diabetic kidney disease

Diabetic kidney disease (DKD) is the most common cause of kidney failure, characterized by chronic inflammation and fibrosis. The complement system is increasingly implicated in the development and progression of diabetic nephropathy. The important complement anaphylatoxins C3a and C5a are key mediators of the innate immune system, which regulates cellular inflammation, oxidative stress, mitochondrial homeostasis and tissue fibrosis. This review summarizes the involvement of anaphylatoxins in the pathogenesis of diabetic kidney disease, highlights their important roles in the pathophysiologic changes of glomerulopathy, tubulointerstitial damage and immune cell infiltration, and discusses the modulatory effects of new anti-diabetic drugs acting on the complement system. Based on available clinical data and findings from the preclinical studies of complement blockade, anaphylatoxin-targeted therapeutics may become a promising approach for patients with DKD in the future.

Current management of chronic kidney disease in type-2 diabetes-A tiered approach: An overview of the joint Association of British Clinical Diabetologists and UK Kidney Association (ABCD-UKKA) guidelines

A growing and significant number of people with diabetes develop chronic kidney disease (CKD). Diabetes-related CKD is a leading cause of end-stage kidney disease (ESKD) and people with diabetes and CKD have high morbidity and mortality, predominantly related to cardiovascular disease (CVD). Despite advances in care over the recent decades, most people with CKD and type 2 diabetes are likely to die of CVD before developing ESKD. Hyperglycaemia and hypertension are modifiable risk factors to prevent onset and progression of CKD and related CVD. People with type 2 diabetes often have dyslipidaemia and CKD per se is an independent risk factor for CVD, therefore people with CKD and type 2 diabetes require intensive lipid lowering to reduce burden of CVD. Recent clinical trials of people with type 2 diabetes and CKD have demonstrated a reduction in composite kidney end point events (significant decline in kidney function, need for kidney replacement therapy and kidney death) with sodium-glucose co-transporter-2 (SGLT-2) inhibitors, non-steroidal mineralocorticoid receptor antagonist finerenone and glucagon-like peptide 1 receptor agonists. The Association of British Clinical Diabetologists (ABCD) and UK Kidney Association (UKKA) Diabetic Kidney Disease Clinical Speciality Group have previously undertaken a narrative review and critical appraisal of the available evidence to inform clinical practice guidelines for the management of hyperglycaemia, hyperlipidaemia and hypertension in adults with type 2 diabetes and CKD. This 2024 abbreviated updated guidance summarises the recommendations and the implications for clinical practice for healthcare professionals who treat people with diabetes and CKD in primary, community and secondary care settings.

Incidence of hyperkalemia RAASi and SGLT-2i treatment in individuals with diabetic kidney disease: a systematic review and network meta-analysis

Background

This study aims to evaluate the incidence of hyperkalemia and serum potassium levels associated with the use of sodium-glucose cotransporter-2 inhibitors (SGLT-2i), renin-angiotensin-aldosterone system inhibitors (RAASi) and concurrent use of these medications in individuals with diabetic kidney disease (DKD).

Methods

A comprehensive systematic search was performed in EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus, and PubMed database, covering studies up to March 2024. Relevant randomized controlled trials (RCT) included adults with DKD who were treated with SGLT-2i and RAASi or their combination, with a minimum follow-up duration of 12 weeks. The primary outcomes assessed were the incidence of hyperkalemia and serum potassium levels were the primary outcomes assessed. The surface under the cumulative ranking curves (SUCRA) was utilized for ranking purposes.

Results

The study included 36 trials, encompassing 45,120 participants, comparing various interventions. SGLT-2i (SUCRA = 88.5%) was found to significantly reduce the risk of hyperkalemia. In contrast, the combination of ACEI/ARB + MRA (SUCRA = 5.7%) increased the risk of hyperkalemia. However, when SGLT-2i was added to the ACEI/ARB + MRA regimen, the incidence of hyperkalemia was found to decrease. Subgroup analyses on MRA showed that ACEI/ARB + spironolactone posed the highest risk of hyperkalemia. ACEI/ARB + SGLT-2i mitigated serum potassium level.

Conclusion

SGLT-2i was effective in reducing the incidence of hyperkalemia incidence, whereas a combination of ACEI/ARB and MRA might elevate the incidence of hyperkalemia in individuals with DKD.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier CRD42024552810.

Mechanisms, Biomarkers, and Treatment Approaches for Diabetic Kidney Disease: Current Insights and Future Perspectives

Diabetic Kidney Disease (DKD) is the leading cause of end-stage renal disease (ESRD) worldwide. Among individuals with type 1 diabetes mellitus (T1DM), 30-40% are at risk of developing DKD. This review focuses on the mechanistic processes, available and emerging biomarkers for diagnosing, monitoring, and preventing DKD, as well as treatment options targeted at DKD patients. A literature search was conducted on PubMed and Scopus using specific keywords. Inclusion and exclusion criteria were applied to select the articles used for this review. The literature highlights various mechanisms involved in the progression of DKD to more severe stages. Additionally, several biomarkers have been identified, which aid in diagnosing and monitoring the disease. Furthermore, numerous treatment approaches are being explored to address the underlying causes of DKD. Advanced research is exploring new medications to aid in DKD remission; sodium-glucose cotransport (SGLT2) inhibitors and finerenone, in particular, are gaining attention for their novel renoprotective effects. DKD is a major complication of diabetes, marked by complex and multifactorial mechanisms. Thus, understanding these processes is essential for developing targeted therapies to potentially reverse DKD progression. Biomarkers show promise for early diagnosis and monitoring of disease progression, while current treatment strategies underscore the importance of a multifaceted approach.

Urine Tricarboxylic Acid Cycle Metabolites and Risk of End-stage Kidney Disease in Patients With Type 2 Diabetes

CONTEXT

Metabolites in the tricarboxylic acid (TCA) pathway have pleiotropic functions.

OBJECTIVE

To study the association between urine TCA cycle metabolites and the risk for chronic kidney disease progression in individuals with type 2 diabetes.

DESIGN, SETTING AND PARTICIPANTS

A prospective study in a discovery (n = 1826) and a validation (n = 1235) cohort of people with type 2 diabetes in a regional hospital and a primary care facility.

EXPOSURE AND OUTCOME

Urine lactate, pyruvate, citrate, alpha-ketoglutarate, succinate, fumarate, and malate were measured by mass spectrometry. Chronic kidney disease progression was defined as a composite of sustained estimated glomerular filtration rate below 15 mL/min/1.73 m2, dialysis, renal death, or doubling of serum creatinine.

RESULTS

During a median of 9.2 (interquartile range 8.1-9.7) and 4.0 (3.2-5.1) years of follow-up, 213 and 107 renal events were identified. Cox regression suggested that urine lactate, fumarate, and malate were associated with an increased risk (adjusted hazard ratio, [95% CI] 1.63 [1.16-2.28], 1.82 [1.17-2.82], and 1.49 [1.05-2.11], per SD), whereas citrate was associated with a low risk (aHR 0.83 [0.72-0.96] per SD) for the renal outcome after adjustment for cardiorenal risk factors. These findings were reproducible in the validation cohort. Noteworthy, fumarate and citrate were independently associated with the renal outcome after additional adjustment for other metabolites.

CONCLUSION

Urine fumarate and citrate predict the risk for progression to end-stage kidney disease independent of clinical risk factors and other urine metabolites. These 2 metabolites in TCA cycle pathway may play important roles in the pathophysiological network, underpinning progressive loss of kidney function in patients with type 2 diabetes.

Risk factors for developing osteoporosis in diabetic kidney disease and its correlation with calcium-phosphorus metabolism, FGF23, and Klotho

BACKGROUND

The progression of diabetic kidney disease (DKD) affects the patient's kidney glomeruli and tubules, whose normal functioning is essential for maintaining normal calcium (Ca) and phosphorus (P) metabolism in the body. The risk of developing osteoporosis (OP) in patients with DKD increases with the aggravation of the disease, including a higher risk of fractures, which not only affects the quality of life of patients but also increases the risk of death.

AIM

To analyze the risk factors for the development of OP in patients with DKD and their correlation with Ca-P metabolic indices, fibroblast growth factor 23 (FGF23), and Klotho.

METHODS

One hundred and fifty-eight patients with DKD who were admitted into the Wuhu Second People's Hospital from September 2019 to May 2021 were selected and divided into an OP group (n = 103) and a normal bone mass group (n = 55) according to their X-ray bone densitometry results. Baseline data and differences in Ca-P biochemical indices, FGF23, and Klotho were compared. The correlation of Ca-P metabolic indices with FGF23 and Klotho was discussed, and the related factors affecting OP in patients with DKD were examined by multivariate logistic regression analysis.

RESULTS

The OP group had a higher proportion of females, an older age, and a longer diabetes mellitus duration than the normal group (all P < 0.05). Patients in the OP group exhibited significantly higher levels of intact parathyroid hormone (iPTH), blood P, Ca-P product (Ca × P), fractional excretion of phosphate (FeP), and FGF23, as well as lower estimated glomerular filtration rate, blood Ca, 24-hour urinary phosphate excretion (24-hour UPE), and Klotho levels (all P < 0.05). In the OP group, 25-(OH)-D3, blood Ca, and 24-hour UPE were negatively correlated with FGF23 and positively correlated with Klotho. In contrast, iPTH, blood Ca, Ca × P, and FeP exhibited a positive correlation with FGF23 and an inverse association with Klotho (all P < 0.05). Moreover, 25-(OH)-D3, iPTH, blood Ca, FePO4, FGF23, Klotho, age, and female gender were key factors that affected the lumbar and left femoral neck bone mineral density.

CONCLUSION

The Ca-P metabolism metabolic indexes, FGF23, and Klotho in patients with DKD are closely related to the occurrence and development of OP.

LOX-induced tubulointerstitial fibrosis via the TGF-β/LOX/Snail axis in diabetic mice

BACKGROUND

The partial epithelial-mesenchymal transition (EMT) is emerging as a significant mechanism in diabetic nephropathy (DN). LOX is a copper amine oxidase conventionally thought to act by crosslinking collagen. However, the role of LOX in partial EMT and fibrotic progression in diabetic nephropathy has not been investigated experimentally.

METHODS

The bulk RNA sequencing and single-nuclei RNA sequencing (snRNA-seq) analysis were explored to find the role of LOX in diabetic nephropathy. We then investigated the partial EMT and the possible signaling pathway of LOX, both in vivo and in vitro by LOX inhibition experiments in diabetic mice and HK-2 cells. Besides, we further assessed kidney fibrosis and renal function.

RESULTS

LOX expression was elevated in kidneys of diabetic mice. Additionally, snRNA-seq results indicated that LOX expression was higher in partial epithelial-mesenchymal transition proximal tubular (PemtPT) epithelial cells. Moreover, we found that increased LOX prompted partial EMT of renal tubular epithelial cells (RTECs) by modulating the transcription factor Snail both in vivo and in vitro. Remarkably, inhibition of LOX effectively mitigated the partial EMT of RTECs in diabetic mice, thereby attenuating kidney fibrosis and enhancing renal function. Additionally, we identified the TGF-β signaling pathway as an upstream regulator of LOX, and inhibiting LOX partially reversed the partial EMT program in HK-2 cells induced by the TGF-β signaling pathway.

CONCLUSIONS

Hyperglycemia induces partial EMT of RTECs via the TGF-β/LOX/Snail axis, thereby contributing to diabetic kidney fibrosis. Inhibiting LOX can effectively reverse the partial EMT of RTECs, diminish diabetic kidney fibrosis, and improve renal function.

Curcumin nanocrystals ameliorate ferroptosis of diabetic nephropathy through glutathione peroxidase 4

Objective

The aim of this study was to investigate the effect of curcumin nanocrystals (Cur-NCs) on ferroptosis in high-glucose (HG)-induced HK-2 cells and streptozotocin (STZ)-induced diabetic nephropathy model (DN) rats. The purpose is to determine whether Cur NCs can become a promising treatment option for diabetes nephropathy by reducing ferroptosis.

Methods

Cur-NCs were prepared using microfluidic technology and studied using dynamic light scattering and transmission electron microscopy. HK-2 cells were treated with 30 mM HG to create a renal tubule damage cell model. Then, cell viability was evaluated in HK-2 cells treated with varying concentrations of Cur-NCs (0.23, 0.47, 0.94, 1.87, 3.75, 7.5, 15, and 30 μg/mL) using Cell Counting Kit-8 (CCK-8). Furthermore, in vivo experiments were carried out to investigate the roles of Cur-NCs in STZ-induced DN rats.

Results

The results showed that HG treatment greatly enhanced the levels of LDH, MDA, Iron, lipid ROS, apoptosis, NCOA4, TFR-1, while decreasing the expression of GSH, GPX4, SLC7A11, and FTH-1. These effects induced by HG could be attenuated by Cur-NCs. Cur-NCs also reduced the HG-induced decrease in cell viability, as well as the increase in lipid ROS and cell apoptosis, however erastin could inhibit their effects. Furthermore, the in vivo results showed that Cur-NCs reduced ferroptosis and inhibited renal damage in DN rats.

Conclusion

This study demonstrates that Cur-NCs can significantly attenuate ferroptosis in a STZ-induced renal damage model by recovering GPX4, implying that Cur-NCs may be a promising therapy option for DN.

FGF21 ameliorates diabetic nephropathy through CDK1-dependently regulating the cell cycle

Background

Diabetic nephropathy (DN) is a prevalent global renal illness and one of the main causes of end-stage renal disease (ESRD). FGF21 has been shown to ameliorate diabetic nephropathy, and in addition FGF-21-treated mice impeded mitogenicity, whereas it is unclear whether FGF21 can influence DN progression by regulating the cell cycle in diabetic nephropathy.

Methods

In order to create a diabetic model, STZ injections were given to C57BL/6J mice for this investigation. Then, FGF21 was administered, and renal tissue examination and pathological observation were combined with an assessment of glomerular injury, inflammation, oxidative stress, and the fibrinogen system in mice following the administration of the intervention. Furthermore, we used db/db mice and FGF21 direct therapy for 8 weeks to investigate changes in fasting glucose and creatinine expression as well as pathological changes in glomeruli glycogen deposition, fibrosis, and nephrin expression. To investigate the mechanism of action of FGF21 in the treatment of glycolytic kidney, transcriptome sequencing of renal tissues and KEGG pathway enrichment analysis of differential genes were performed.

Results

The study's findings demonstrated that FGF21 intervention increased clotting time, decreased oxidative stress and inflammation, and avoided thrombosis in addition to considerably improving glomerular filtration damage. After 8 weeks of FGF21 treatment, glomerular glycogen deposition, fibrosis, and renin expression decreased in db/db mice. Moreover, there was a notable reduction of creatinine and fasting blood glucose levels. Additionally, the CDK1 gene, a key player in controlling the cell cycle, was discovered through examination of the transcriptome sequencing data. It was also shown that FGF21 dramatically reduces the expression of CDK1, which may help diabetic nephropathy by averting mitotic catastrophe and changing the renal cell cycle.

Conclusion

In short, FGF21 improved the development of diabetic nephropathy in diabetic nephropathy-affected animals by reducing glomerular filtration damage, inflammation, and oxidative stress, inhibiting the formation of thrombus, and controlling the cell cycle through CDK1.

The role of SIRT1 in kidney diseases

SIRT1, a nicotinamide adenine dinucleotide (NAD +)-dependent class III histone deacetylase, exhibits a high level of expression within renal tissues. It has garnered considerable recognition for its pivotal role in modulating signaling pathways intricately linked with the aging process; however, it extends beyond this in the organism. The literature reports that SIRT1 regulates biological processes such as glucose metabolism, lipid metabolism, oxidative stress, inflammation, autophagy, endoplasmic reticulum stress, and apoptosis. Therefore, our study reviews the primary mechanisms by which SIRT1 induces kidney disease and the regulation of related signaling pathways in different models of renal disease. We also discuss commonly studied SIRT1-targeted interventional drugs reported in the literature, including inhibitors (e.g., Ex-527) and activators (e.g., resveratrol). This study aims to provide theoretical foundations and clinical insights for the development and screening of clinical drugs targeting SIRT1, aiming at enhanced scientific approaches for the prevention and treatment of kidney diseases.

Isoquercitrin improves diabetes nephropathy by inhibiting the sodium-glucose co-transporter-2 pathway

Diabetic nephropathy (DN) is one of the most severe kidney complications and the primary contributor to end-stage renal disease on a global scale. It exacerbates the morbidity, mortality, and financial burden for individuals with diabetes. Isoquercitrin, a natural compound found in various plants, has demonstrated potential as an antidiabetic agent. However, it remains uncertain whether isoquercitrin exerts a protective effect on DN. Therefore, the objective of this study was to explore whether isoquercitrin confers a protective effect on DN and its potential mechanism. In vivo, a mouse model of DN induced by streptozotocin was established in the study. The hypoglycemic effect of isoquercitrin was assessed by measuring fasting blood glucose levels, insulin tolerance tests, and glucose tolerance test in animals. Urinary albumin creatinine ratio, serum lipid levels, and pathological changes in renal tissues were measured to evaluate the protective effect of isoquercitrin against DN. The expression of Sodium glucose co-transporter-2(SGLT2) was analyzed using real-time quantitative PCR and immunohistochemistry. The studies suggest that isoquercitrin significantly reduces fasting blood glucose levels, enhances the body's capacity to regulate blood glucose and insulin resistance, and facilitates renal pathology and renal function. Simultaneously, it can lower blood lipids (total cholesterol and triglyceride) and improve the risk factors of DN. Meanwhile, isoquercitrin suppressed the expression of SGLT2 in renal tissues of DN mouse models. In vitro, real-time quantitative PCR and Western blot were used to detect the expression of SGLT2 in the human renal tubular epithelial (HK-2) cells. The effects of isoquercitrin on the survival rate and glucose uptake capacity of HK-2 cells were determined by Cell-Counting-Kit-8 and glucose uptake methods. The results demonstrate that isoquercitrin suppressed the up-regulation of SGLT2 mRNA and protein in high-glucose-induced HK-2 cells. Additionally, isoquercitrin inhibited glucose uptake in HK-2 cells and mitigated high-sugar-induced damage. Thus, this study has concluded that isoquercitrin exhibits hypoglycemic and renal protective effects by inhibiting the SGLT2 pathway, indicating its potential as a promising anti-DN drug deserving further clinical investigation.

Phillygenin improves diabetic nephropathy by inhibiting inflammation and apoptosis via regulating TLR4/MyD88/NF-κB and PI3K/AKT/GSK3β signaling pathways

BACKGROUND

Phillygenin (PHI), a main bioactive compound found in the fruit of Forsythia suspensa, exhibits antiviral, antioxidant, anti-inflammatory, and antihypertensive activities. However, the molecular mechanisms underlying its effects on diabetic nephropathy (DN) remain unclear.

PURPOSE

To evaluate the therapeutic effects of PHI on DN and elucidate the molecular mechanisms involved.

METHODS

Cell viability assays and RNA-seq analyses were performed to identify potential mechanisms through which PHI regulates HG-induced MPCs. The therapeutic efficacy of PHI was assessed in both DN cells and mouse models. Cytokine levels were measured using ELISA, while the expression levels of key signaling pathways, including TLR4/MyD88/NF-κB and PI3K/AKT/GSK3β along with downstream effectors were analyzed via immunoblotting, immunofluorescence, and immunohistochemical staining.

RESULTS

PHI inhibited inflammatory responses and alleviated apoptosis by reducing the expression levels of IL-6, TNF-α, IL-1β, TLR4, MyD88, NF-κB, and cleaved caspase-3, while enhancing the phosphorylation of PI3K, AKT, GSK3β (Ser9), and pro-caspase-3 in MPCs under HG conditions in vitro. Additionally, in vivo experiments demonstrated that treatment with PHI (50 mg/kg) in db/db mice effectively improved renal function and attenuated kidney injury by reducing the urinary albumin-to-creatinine ratio (UACR), mitigating podocyte apoptosis, and inhibiting inflammatory via modulation of the TLR4/MyD88/NF-κB and PI3K/AKT/GSK3β signaling pathways.

CONCLUSION

PHI inhibits inflammation and apoptosis in vitro and alleviates diabetic kidney injury in db/db mice by interfering TLR4/MyD88/NF-κB and PI3K/AKT/GSK3β signaling pathways. Thus, this study reveals for the first time that PHI is a potential novel therapeutic agent for DN.

CD38 deficiency prevents diabetic nephropathy by inhibiting lipid accumulation and oxidative stress through activation of the SIRT3 pathway

Diabetic nephropathy (DN) is one of the most common complications of diabetes. Our previous study showed that CD38 knockout (CD38KO) mice had protective effects on many diseases. However, the roles and mechanisms of CD38 in DN remain unknown. Here, DN mice were generated by high-fat diet (HFD) feeding plus streptozotocin (STZ) injection in male CD38KO and CD38flox mice. Mesangial cells (SV40 MES 13 cells) were used to mimic the injury of DN with palPagination Donemitic acid (PA) treatment in vitro. Our results showed that CD38 expression was significantly increased in kidney of diabetic CD38flox mice and SV40 MES 13 cells treated with PA. CD38KO mice were significantly resistant to diabetes-induced renal injury. Moreover, CD38 deficiency markedly decreased HFD/STZ-induced lipid accumulation, fibrosis, and oxidative stress in kidney tissue. In contrast, overexpression of CD38 aggravated PA-induced lipid accumulation and oxidative stress. CD38 deficiency increased expression of SIRT3, while overexpression of CD38 decreased its expression. More importantly, 3-TYP, an inhibitor of SIRT3, significantly enhanced PA-induced lipid accumulation and oxidative stress in CD38 overexpressing cell lines. In conclusion, our results demonstrated that CD38 deficiency prevented DN by inhibiting lipid accumulation and oxidative stress through activation of the SIRT3 pathway.

Single-Cell Analysis Provides New Insights into the Roles of Tertiary Lymphoid Structures and Immune Cell Infiltration in Kidney Injury and Chronic Kidney Disease

Chronic kidney disease (CKD) is a global health concern with high morbidity and mortality. Acute kidney injury (AKI) is a pivotal risk factor for the progression of CKD, and the rate of AKI-to-CKD progression increases with aging. Intrarenal inflammation is a fundamental mechanism underlying AKI-to-CKD progression. Tertiary lymphoid structures (TLSs), ectopic lymphoid aggregates formed in nonlymphoid organs, develop in aged injured kidneys, but not in young kidneys, with prolonged inflammation and maladaptive repair, which potentially exacerbates AKI-to-CKD progression in aged individuals. Dysregulated immune responses are involved in the pathogenesis of various kidney diseases, such as IgA nephropathy, lupus nephritis, and diabetic kidney diseases, thereby deteriorating kidney function. TLSs also develop in several kidney diseases, including transplanted kidneys and renal cell carcinoma. However, the precise immunologic mechanisms driving AKI-to-CKD progression and development of these kidney diseases remain unclear, which hinders the development of novel therapeutic approaches. This review aims to describe recent findings from single-cell analysis of cellular heterogeneity and complex interactions among immune and renal parenchymal cells, which potentially contribute to the pathogenesis of AKI-to-CKD progression and other kidney diseases, highlighting the mechanisms of formation and pathogenic roles of TLSs in aged injured kidneys.