The Concept and the Epidemiology of Diabetic Nephropathy Have Changed in Recent Years

Asiaticoside improves diabetic nephropathy by reducing inflammation, oxidative stress, and fibrosis: An in vitro and in vivo study

BACKGROUND

Diabetic nephropathy (DN) is a severe microvascular complication of diabetes characterized by inflammation, oxidative stress, and renal fibrosis. Asiaticoside (AC) exhibits anti-inflammatory, antioxidant, and anti-fibrotic properties, suggesting potential therapeutic benefits for DN. This study aimed to investigate the protective effects of AC against DN and elucidate the underlying mechanisms involving the nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase-1 (HO-1) antioxidant pathway.

AIM

To investigate the renoprotective effects of AC against DN and elucidate the role of the NRF2/HO-1 pathway.

METHODS

The effects of AC on high glucose (HG)-induced proliferation, inflammation, oxidative stress, and fibrosis were evaluated in rat glomerular mesangial cells (HBZY-1) in vitro. A streptozotocin-induced DN rat model was established to assess the in vivo impact of AC on renal injury, inflammation, oxidative stress, and fibrosis. The involvement of the NRF2/HO-1 pathway was examined using pharmacological inhibition studies in the cell model.

RESULTS

AC inhibited HG-induced HBZY-1 cell proliferation and significantly improved various indicators of DN in rats, including reduced body weight, and elevated blood glucose, serum creatinine, blood urea nitrogen, and 24-h urine protein. Both in vitro and in vivo studies demonstrated that AC decreased inflammation and oxidative stress by reducing interleukin (IL)-6, IL-8, tumor necrosis factor-alpha, reactive oxygen species, and malondialdehyde levels while increasing superoxide dismutase activity. Additionally, AC suppressed the expression of fibrogenic markers such as collagen I, collagen IV, and fibronectin. AC activated NRF2 expression in the nucleus and increased HO-1 and NAD(P)H dehydrogenase (Quinone) 1 protein expression in renal tissues and HG-induced HBZY-1 cells.

CONCLUSION

AC improves DN by reducing inflammation, oxidative stress, and fibrosis through the activation of the NRF2/HO-1 signaling pathway. These findings not only highlight AC as a promising therapeutic candidate for DN but also underscore the potential of targeting the NRF2/HO-1 pathway in developing novel treatments for other chronic kidney diseases characterized by oxidative stress and inflammation.

Huperzine A targets Apolipoprotein E: A potential therapeutic drug for diabetic nephropathy based on omics analysis

AIMS

Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM) without curative interventions currently. Huperzine A (Hup A), a natural alkaloid, has demonstrated significant hypoglycemic and anti-inflammatory effects. We aim to investigate the protective effects of Hup A on DN and explore the underlying mechanisms METHODS: We applied STZ induced diabetic rats as DN model and leveraged combination analysis of the transcriptome, metabolome, microbiome, and network pharmacology (NP). The total effect of Hup A on DN was detected (i.e. urine protein, renal tissue structure) and the differential genes were further verified at the level of diabetic patients, db/db mice and cells. Clinical data and small interfering RNA (siRNA)-Apoe were adopted.

RESULTS

Hup A alleviated kidney injury in DN rats. Transcriptomics data and Western blot indicated that the improvement in DN was primarily associated with Apoe and Apoc2. Additionally, metabolomics data demonstrated that DN-induced lipid metabolism disruption was regulated by Hup A, potentially involving sphingosine. Hup A also enriched microbial diversity and ameliorated DN-induced microbiota imbalance. Spearman's correlation analysis demonstrated significant associations among the transcriptome, metabolome, and microbiome. Apoe level was positively correlated with clinical biomarkers in DN patients. Si-Apoe also played protective role in podocytes. NP analysis also suggested that Hup A may treat DN by modulating lipid metabolism, microbial homeostasis, and apoptosis, further validating our findings.

CONCLUSIONS

Collectively, we provide the first evidence of the therapeutic effect of Hup A on DN, indicating that Hup A is a potential drug for the prevention and treatment of DN.

Neutrophil-to-lymphocyte ratio associated with renal function in type 2 diabetic patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a leading risk factor for the development and progression of chronic kidney disease (CKD). However, an accurate and convenient marker for early detection and appropriate management of CKD in individuals with T2DM is limited. Recent studies have demonstrated a strong correlation between the neutrophil-to-lymphocyte ratio (NLR) and CKD. Nonetheless, the predictive value of NLR for renal damage in type 2 diabetic patients remains understudied.

AIM

To investigate the relationship between NLR and renal function in T2DM patients.

METHODS

This study included 1040 adults aged 65 or older with T2DM from Shanghai's Community Health Service Center. The total number of neutrophils and lymphocytes was detected, and NLR levels were calculated. CKD was defined as an estimated glomerular filtration rate ≤ 60 mL/min/1.73 m². Participants were divided into four groups based on NLR levels. The clinical data and biochemical characteristics were compared among groups. A multivariate logistic regression model was used to analyze the association between NLR levels and CKD.

RESULTS

Significant differences were found in terms of sex, serum creatinine, blood urea nitrogen, total cholesterol, and low-density lipoprotein cholesterol among patients with T2DM in different NLR groups (P < 0.0007). T2DM patients in the highest NLR quartile had a higher prevalence of CKD (P for trend = 0.0011). Multivariate logistic regression analysis indicated that a high NLR was an independent risk factor for CKD in T2DM patients even after adjustment for important clinical and pathological parameters (P = 0.0001, odds ratio = 1.41, 95% confidence intervals: 1.18-1.68).

CONCLUSION

An elevated NLR in patients with T2DM is associated with higher prevalence of CKD, suggesting that it could be a marker for the detection and evaluation of diabetic kidney disease.

The unique association between the level of plateletcrit and the prevalence of diabetic kidney disease: a cross-sectional study

Objective

The activation of platelets in individuals with type 2 diabetes mellitus (T2DM) triggers inflammation and hemodynamic abnormalities, contributing to the development of diabetic kidney disease (DKD). Despite this, research into the relationship between plateletcrit (PCT) levels and DKD is sparse, with inconsistent conclusions drawn regarding the connection between various platelet parameters and DKD. This highlights the necessity for comprehensive, large-scale population studies. Therefore, our objective is to explore the association between PCT levels and various platelet parameters in relation to DKD.

Methods

In this cross-sectional study, hematological parameter data were collected from a cohort of 4,302 hospitalized Chinese patients. We analyzed the relationships between PCT, platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR), and DKD, along with the urinary albumin-to-creatinine ratio (UACR), and estimated glomerular filtration rate (eGFR). Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic potential of these parameters.

Results

DKD patients exhibited significantly higher PCT levels compared to those without DKD. Multivariate regression analysis identified elevated PCT and PLT levels as potential independent risk factors for both DKD and UACR, while lower MPV levels might serve as independent protective factors for eGFR. The areas under the ROC curve for PCT in relation to DKD and UACR (≥30 mg/g) were 0.523 and 0.526, respectively. The area under the ROC curve for PLT in relation to UACR (≥30 mg/g) was 0.523.

Conclusion

PCT demonstrates a weak diagnostic value for T2DM patients at risk of developing DKD and experiencing proteinuria, and PLT shows a similarly modest diagnostic utility for detecting proteinuria. These insights contribute to a deeper understanding of the complex dynamics involved in DKD. Additionally, incorporating these markers into routine clinical assessments could enhance risk stratification, facilitating early interventions and personalized management strategies.

Exosomes derived from mesenchymal stem cells in diabetes and diabetic complications

Diabetes, a group of metabolic disorders, constitutes an important global health problem. Diabetes and its complications place a heavy financial strain on both patients and the global healthcare establishment. The lack of effective treatments contributes to this pessimistic situation and negative outlook. Exosomes released from mesenchymal stromal cells (MSCs) have emerged as the most likely new breakthrough and advancement in treating of diabetes and diabetes-associated complication due to its capacity of intercellular communication, modulating the local microenvironment, and regulating cellular processes. In the present review, we briefly outlined the properties of MSCs-derived exosomes, provided a thorough summary of their biological functions and potential uses in diabetes and its related complications.

CircGAB1 Facilitates Podocyte Injury Through Sponging miR-346 and Activating MAPK6 in Diabetic Nephropathy

BACKGROUND

Podocyte injury is very important process in diabetic nephropathy (DN) progression. Circular RNA (circRNA) takes part in regulating the advancement of DN. Herein, we explored the role and mechanism of circGAB1 in DN progression.

METHODS

The abundances of circGAB1, microRNA-346 (miR-346) and mitogen-activated protein kinase 6 (MAPK6) were detected by qRT-PCR in DN serum samples and podocyte HGPC. Moreover, cell viability and apoptosis were determined using CCK8 assay and flow cytometry. Also, the protein levels of MAPK6, proliferation-related markers and apoptosis-related markers were analyzed by western blot. ELISA assay was used to measure the levels of inflammatory factors, and corresponding kits were used to detect the levels of oxidative stress-related markers. The relationship between miR-346 and circGAB1 or MAPK6 was distinguished by dual-luciferase reporter assay.

RESULTS

CircGAB1 expression was increased in DN serum samples and HG-treated HGPC cells. CircGAB1 knockdown inhibited HG-induced apoptosis, inflammatory response and oxidative stress in HGPC cells. In terms of mechanism, circGAB1 sponged miR-346, and miR-346 targeted MAPK6. The inhibition effect of circGAB1 knockdown on HG-induced podocyte injury could be reversed by miR-346 inhibitor. Moreover, miR-346 overexpression repressed HG-induced podocyte injury by targeting MAPK6. CircGAB1 served as miR-346 sponge to positively regulate MAPK6.

CONCLUSION

CircGAB1 contributed to podocyte injury through mediating miR-346/MAPK6 axis, suggesting that circGAB1 might promote DN progression.

Low Levels of Metrnl are Linked to the Deterioration of Diabetic Kidney Disease

Objective

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Metrnl is a secreted protein that plays an important role in kidney disease. The aim of this study was to investigate DKD-related factors and the correlation between serum Metrnl levels and the severity of DKD.

Methods

Ninety-six type 2 diabetes mellitus (T2DM) patients and 45 DKD patients were included in the study. A range of parameters were measured simultaneously, including waist-to-hip ratio (WHR), body mass index (BMI), urinary albumin/creatinine ratio (UACR), monocyte-lymphocyte ratio (MLR), albumin/globulin (A/G), liver and kidney function, blood lipid profile, islet function, and others. Subsequently, the related factors and predictive significance of DKD were identified. The correlation between the relevant factors of DKD and serum Metrnl levels with DKD was evaluated.

Results

The duration of the disease (OR: 1.12, 95% CI: 1.01-1.24, P=0.031), hypertension (OR: 4.86, 95% CI: 1.16-20.49, P=0.031), fasting blood glucose (OR: 1.23, 95% CI: 1.03-1.48, P=0.025), WHR (OR: 2.53, 95% CI: 1.03-6.22, P=0.044), and MLR (OR: 1.91, 95% CI: 1.18-3.08, P=0.008) are independent risk factors for DKD (P < 0.05). Conversely, A/G (OR: 0.13, 95% CI: 0.02-0.76, P=0.024) and Metrnl (OR: 0.99, 95% CI: 0.98-1.00, P=0.001) have been identified as protective factors against DKD. Furthermore, the level of Metrnl was negatively correlated with the severity of DKD (rs=-0.447, P<0.001). The area under receiver operating characteristic (ROC) curves for the diagnostic accuracy of Metrnl for DKD is 0.765 (95% CI: 0.686-0.844).

Conclusion

The duration of the disease, hypertension, fasting blood glucose, WHR, and MLR are major risk factors for DKD. Metrnl and A/G are protective factors for DKD. Serum Metrnl concentrations are inversely correlated with DKD severity.

Utilizing molecular docking and cell validation to explore the potential mechanisms of lupenone attenuating the inflammatory response via NF-κB pathway

Diabetic nephropathy (DN), a common microvascular complicating disease of diabetes. Lupenone, a pentacyclic triterpenoid, has anti-inflammatory effects and can prevent type 2 diabetes mellitus and treat renal damage, however, the effects and mechanisms of lupenone in DN remain unclear. Thereby,the MTT method was used to investigate the antiproliferative effect of lupenoneon the cell line rat glomerular mesangial cells (HBZY-1). Molecular docking was used to investigate the combination of lupenone and MCP-1, IL-1β, TNF-α, IKKβ, IκBα, and NF-κB p65 proteins. The expression of mRNA of the pro-inflammatory cytokines (MCP-1, IL-1β and TNF-α) and the NF-κB signalling pathway in HBZY-1 cells were assessed by RT-PCR. The protein expressions of pro-inflammatory cytokines and NF-κB pathway were got by Western blot. Result showed that lupenone inhibited the proliferative activity of HBZY-1 cells at non-cytotoxic concentrations. Molecular docking results showed that lupenone combined well with the target proteins. Moreover, lupenone could significantly reduced the mRNA and protein expressions for pro-inflammatory cytokines and IKKβ, p-p65 and p-IκBα. Lupenone may play an anti-inflammatory role in DN treatment by inhibiting the NF-κB signalling pathway. These results provided a new understanding of the pharmacological mechanisms of lupenone in treatment of DN.

Association between neutrophil-to-lymphocyte ratio and diabetic kidney disease in type 2 diabetes mellitus patients: a cross-sectional study

Aims

This investigation examined the possibility of a relationship between neutrophil-to-lymphocyte ratio (NLR) and diabetic kidney disease (DKD) in type 2 diabetes mellitus (T2DM) patients.

Methods

Adults with T2DM who were included in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2020 were the subjects of the current cross-sectional investigation. Low estimated glomerular filtration rate (eGFR) (< 60 mL/min/1.73 m2) or albuminuria (urinary albumin-to-creatinine ratio (ACR) ≥ 30 mg/g) in T2DM patients were the diagnostic criteria for DKD. Weighted multivariable logistic regression models and generalized additive models were used to investigate the independent relationships between NLR levels with DKD, albuminuria, and low-eGFR. Additionally, we examined the relationships between DKD, albuminuria, and low-eGFR with other inflammatory markers, such as the aggregate index of systemic inflammation (AISI), systemic immune-inflammation index (SII), system inflammation response index (SIRI), and platelet-to-lymphocyte ratio (PLR) and monocyte-to-lymphocyte ratio (MLR). Their diagnostic capabilities were evaluated and contrasted using receiver operating characteristic (ROC) curves.

Results

44.65% of the 7,153 participants who were recruited for this study were males. DKD, albuminuria, and low-eGFR were prevalent in 31.76%, 23.08%, and 14.55% of cases, respectively. Positive correlations were seen between the NLR with the prevalences of DKD, albuminuria, and low-eGFR. Subgroup analysis and interaction tests revealed that the associations of NLR with DKD, albuminuria, and low-eGFR were not significantly different across populations. In addition, MLR, SII and SIRI showed positive associations with the prevalence of DKD. ROC analysis discovered that when compared to other inflammatory markers (MLR, PLR, SII, SIRI, and AISI), NLR may demonstrate more discriminatory power and accuracy in assessing the risk of DKD, albuminuria, and low-eGFR.

Conclusion

Compared to other inflammatory markers (MLR, PLR, SII, SIRI, and AISI), NLR may serve as the more effective potential inflammatory marker for identifying the risk of DKD, albuminuria, and low-eGFR in US T2DM patients. T2DM patients with elevated levels of NLR, MLR, SII, and SIRI should be closely monitored for their potential risk to renal function.

The Effects of Apigenin in the Treatment of Diabetic Nephropathy: A Systematic Review of Non-clinical Studies

PURPOSE

Diabetes is one of the important and growing diseases in the world. Among the most common diabetic complications are renal adverse effects. The use of apigenin may prevent the development and progression of diabetes-related injuries. The current study aims to review the effects of apigenin in the treatment of diabetic nephropathy.

METHODS

In this review, a systematic search was performed based on PRISMA guidelines for obtaining all relevant studies on "the effects of apigenin against diabetic nephropathy" in various electronic databases up to September 2022. Ninety-one articles were obtained and screened in accordance with the predefined inclusion and exclusion criteria. Seven eligible articles were finally included in this review.

RESULTS

The experimental findings revealed that hyperglycemia led to the decreased cell viability of kidney cells and body weight loss and an increased kidney weight of rats; however, apigenin administration had a reverse effect on these evaluated parameters. It was also found that hyperglycemia could induce alterations in the biochemical and renal function-related parameters as well as histopathological injuries in kidney cells or tissue; in contrast, the apigenin administration could ameliorate the hyperglycemia-induced renal adverse effects.

CONCLUSION

The results indicated that the use of apigenin could mitigate diabetes-induced renal adverse effects, mainly through its antioxidant, anti-apoptotic, and anti-inflammatory activities. Since the findings of this study are based on experimental studies, suggesting the use of apigenin (as a nephroprotective agent) against diabetic nephropathy requires further clinical studies.

Effects of total flavones of Abelmoschus manihot (L.) on the treatment of diabetic nephropathy via the activation of solute carriers in renal tubular epithelial cells

As a traditional Chinese medicine, Huangkui capsule (HKC) has been used to treat patients with kidney diseases, including diabetic nephropathy (DN). We have recently demonstrated that HKC could re-regulate the activities of solute carriers (SLC)s in proximal and distal convoluted tubules of kidneys in regression of the development of DN. The main active chemical constituents of HKC are the flavones of Abelmoschus manihot (L.). The current study aims to further evaluate the efficacy of total flavones of A. manihot (TFA) in the regression of DN by analyzing SLC activities in proximal and distal convoluted tubules of kidneys. TFA (0.076 g/kg/d) or vehicle was administered in db/db mice, the animal model of type 2 diabetes and DN, daily via oral gavage for four weeks. Blood glucose levels and urinary albumin-to-creatinine ratio (UACR) were measured and used for the determination of T2D and DN. Ten SLCs, including slc2a2, slc4A1, slc5a2, slc5A3, slc5a8, slc6a20, slc27a2, slc12a3, slc34a1 and slc38a2 were highly expressed in proximal and distinct convoluted tubules of kidneys. Their expression at mRNA and protein levels before and after TFA treatment were analyzed with real-time RT-PCR and immunohistochemistry. Data showed that UACR in the db/db mice after TFA treatment was significantly decreased. Compared with the group of non-diabetic control, slc2a2, slc4A1, slc5a2, slc5A3, slc5a8, slc6a20, slc27a2, slc12a3, slc34a1 and slc38a2 in the group of DN were down-regulated but up-regulated after TFA treatment. Further analyses of whole kidney sections indicated that the numbers and structures of the nephron in db/db mice was increased and improved after TFA treatment. Thereby, the current study provides further evidence that the flavones in A. manihot have pharmacological effects on the treatment of DN by improving the biological function of SLCs in kidneys.

Relationship between GCKR gene rs780094 polymorphism and type 2 diabetes with albuminuria

BACKGROUND

Diabetic kidney disease is one of the common complications of type 2 diabetes (T2D). There are no typical symptoms in the early stage, and the disease will progress to moderate and late stage when albuminuria reaches a high level. Treatment is difficult and the prognosis is poor. At present, the pathogenesis of diabetic kidney disease is still unclear, and it is believed that it is associated with genetic and environmental factors.

AIM

To explore the relationship between the glucokinase regulatory protein (GCKR) gene rs780094 polymorphism and T2D with albuminuria.

METHODS

We selected 252 patients (126 males and 126 females) with T2D admitted to our hospital from January 2020 to October 2020, and 66 healthy people (44 females and 22 males). According to the urinary albumin/creatinine ratio, the subjects were divided into group I (control), group II (T2D with normoalbuminuria), group III (T2D with microalbuminuria), and group IV (T2D with macroalbuminuria). Additionly, the subjects were divided into group M (normal group) or group N (albuminuria group) according to whether they developed albuminuria. We detected the GCKR gene rs780094 polymorphism (C/T) of all subjects, and measured the correlation between GCKR gene rs780094 polymorphism (C/T) and T2D with albuminuria.

RESULTS

Gene distribution and genotype distribution among groups I-IV accorded with the Hardy-Weinberg equilibrium. Genotype frequency was significantly different among the four groups (P = 0.048, χ2 = 7.906). T allele frequency in groups II, III, and IV was significantly higher than that in group I. Logistic regression analysis of the risk factors for T2D with albuminuria showed that the CT + TT genotype (odds ratio = 1.710, 95% confidence interval: 1.172-2.493) was a risk factor.

CONCLUSION

CT + TT genotype is a risk factor for T2D with albuminuria. In the future, we can assess the risk of individuals carrying susceptible genes to delay the onset of T2D.

Sex Difference in the Association Between Serum Versican and Albuminuria in Patients with Type 2 Diabetes Mellitus

Introduction

Diabetic kidney disease (DKD) is one of the major microvascular complications of diabetes. DKD is associated with oxidative stress and inflammation. Versican (VCAN), a chondroitin sulphate proteoglycan, has been proven to participate in oxidative stress and inflammation. This study aimed to explore the overall and sex-based relationship between serum VCAN levels and albuminuria in patients with type 2 diabetes mellitus (T2DM).

Methods

428 patients with T2DM and 84 healthy individuals were enrolled. Patients with diabetes were separated into normal albuminuria, microalbuminuria, and macroalbuminuria groups, according to their urinary albumin/creatinine ratio (UACR). Serum VCAN levels were tested using an enzyme-linked immunosorbent assay.

Results

Compared with males, female patients were older, and had higher total cholesterol and high-density lipoprotein cholesterol, but lower body mass index, diastolic blood pressure, glycated hemoglobin A1, alanine aminotransferase, urinary albumin (UA), and serum creatinine (SCr) (P < 0.05). The VCAN levels in male patients with T2DM were significantly higher than those in the healthy individuals. Male patients with T2DM with albuminuria (micro and macro) had higher levels of VCAN than in patients with normal albuminuria; the highest level was seen in patients with macroalbuminuria (P < 0.05). In male patients with T2DM, serum VCAN correlated positively with systolic blood pressure, blood urea nitrogen, UA, SCr, and UACR, but correlated negatively with the estimated glomerular filtration rate. The area under the receiver operating characteristic curve of serum VCAN to diagnose albuminuria was 0.702, with a corresponding cut-off value of 0.399 ng/mL (P < 0.001). However, the association between serum VCAN and UACR was not observed in female patients with T2DM.

Conclusion

Serum VCAN levels correlated positively with the severity of albuminuria in male patients with T2DM.

Diabetes Mellitus and Prevalence of Other Comorbid Conditions: A Systematic Review

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by elevated blood glucose levels, severity continues to rise worldwide. This systematic review seeks to examine the prevalence of diabetes and its associated comorbid conditions, aiming to provide insights into the multifaceted impact of diabetes on a broader scale. DM exhibits a positive correlation with advancing age, and it's strongly influenced by genetic predisposition. In recent years, there has been a discernible global increase in the prevalence of type 1 diabetes (T1D), as evidenced by extensive epidemiological studies. Individuals with DM frequently have a positive familial history, and the presence of DM in both parents or solely the mother significantly amplifies genetic susceptibility. Moreover, non-genetic factors, such as acute psychological stressors, obesity, pregnancy, and smoking play a pivotal role in the development of DM. Notably, urinary tract infections (UTIs) are a common comorbidity in patients with type 2 diabetes (T2D) and all patients with T1D. T2D is prevalent, particularly among females, and its incidence rises with age. UTIs are prevalent among individuals with diabetes, particularly females, with Escherichia coli (E. coli) isolates being the primary etiological agents responsible for UTI inflammation. Insulin resistance is a common feature in both prediabetes and prehypertension, serving as a precursor to these conditions. The increasing incidence of T2D in regions with high tuberculosis (TB) prevalence emphasizes the significance of understanding DM as a substantial TB risk factor. DM is associated with a threefold elevation in TB risk and a twofold increase in unfavorable outcomes during TB treatment. Notably, the global prevalence of DM has led to a larger population of TB patients with comorbid DM than TB patients coinfected with HIV. Diabetes and sepsis contribute significantly to worldwide morbidity and mortality, with diabetic individuals experiencing more post-sepsis complications and increased mortality. The coexistence of hypertension and T2D is a common comorbidity, with hypertension incidence being twice as high among individuals with diabetes compared to those without, often linked to insulin resistance and a heightened risk of diabetes onset.

Advances in understanding and treating diabetic kidney disease: focus on tubulointerstitial inflammation mechanisms

Diabetic kidney disease (DKD) is a serious complication of diabetes that can lead to end-stage kidney disease. Despite its significant impact, most research has concentrated on the glomerulus, with little attention paid to the tubulointerstitial region, which accounts for the majority of the kidney volume. DKD's tubulointerstitial lesions are characterized by inflammation, fibrosis, and loss of kidney function, and recent studies indicate that these lesions may occur earlier than glomerular lesions. Evidence has shown that inflammatory mechanisms in the tubulointerstitium play a critical role in the development and progression of these lesions. Apart from the renin-angiotensin-aldosterone blockade, Sodium-Glucose Linked Transporter-2(SGLT-2) inhibitors and new types of mineralocorticoid receptor antagonists have emerged as effective ways to treat DKD. Moreover, researchers have proposed potential targeted therapies, such as inhibiting pro-inflammatory cytokines and modulating T cells and macrophages, among others. These therapies have demonstrated promising results in preclinical studies and clinical trials, suggesting their potential to treat DKD-induced tubulointerstitial lesions effectively. Understanding the immune-inflammatory mechanisms underlying DKD-induced tubulointerstitial lesions and developing targeted therapies could significantly improve the treatment and management of DKD. This review summarizes the latest advances in this field, highlighting the importance of focusing on tubulointerstitial inflammation mechanisms to improve DKD outcomes.

Presence of Non-Diabetic Kidney Diseases in Biopsy Specimens of Diabetic Patients' Single Center Experience

The complications of type 2 diabetes mellitus (T2DM) are well known and one of them is diabetic chronic kidney disease (DCKD). Over time, it has become clear that patients with T2DM can have nondiabetic chronic kidney diseases (NDCKD), especially those that affect the glomeruli. Clinical indicators for identifying DCKD from NDCKD with high sensitivity and specificity have not yet been identified. Therefore, kidney biopsy remains the golden standard for DCKD diagnosis in patients with T2DM. Despite some indications for kidney biopsy, criteria for a biopsy differ between countries, regions, and doctors. The aim of the study was to analyze the biopsy findings in our T2DM population and the justification of the biopsy according to widely accepted criteria. This single center retrospective study analyzed data from 74 patients with T2DM who underwent kidney biopsy from January 2014 to January 2021. According to the biopsy data, we categorized31 patients in the DN group, patients with typical diabetic glomerulopathy, 11 patients in the mixed group, patients who had pathohistological elements for both DN and non-DN glomerulopathy, and 32 patients in the non-DN group, patients with primary glomerulopathy not linked with DM. In the non-DN and mixed groups, the most frequent glomerulopathy was mesangioproliferative glomerulonephritis, including IgA and non-IgA forms, found in 10 patients, and membranous nephropathy (MN) in 10 patients. We analyzed several parameters and only the amount of proteinuria was found to be significantly linked to biopsy findings related to DN. With the existing criteria for kidney biopsy, we managed to detect changes in the kidneys in about half of our patients with T2DM. These patients required specific treatment, different from that which we use for DCKD patients.

Diabetes Mellitus and Diabetic Kidney Disease: The Future Is Already Here

Diabetes mellitus (DM) is a metabolic systemic disease with a high rate of morbidity and mortality [...].

Protective effect of Cordyceps sinensis against diabetic kidney disease through promoting proliferation and inhibiting apoptosis of renal proximal tubular cells

BACKGROUND

Diabetic kidney disease (DKD) has mainly been considered as a glomerular disease. Our previous study showed that the progression of DKD was highly correlated with the dysfunction of renal proximal tubular cells. Fermented Cordyceps sinensis (CS), a substitute for natural CS, is a prominent herb widely used in China, and has exhibited excellent efficacy on DKD. However, the underlying mechanisms remain poorly understood.

METHODS

The database analysis was used to identify the main therapeutic targets and pathways of CS involved in DKD treatment. Next, the protective effects of fermented CS on high glucose (HG, 30 mM) induced HK-2 cell injury was validated through cell proliferation and apoptosis assay, including CCK-8, EdU and TUNEL. Finally, quantitative real‑time PCR (qRT-PCR) and western blotting were used to verify key target genes.

RESULTS

Our results revealed that 9 main targets (RELA, JNK1, PTEN, VEGFA, EGF, ERK2, CASP3, AKT1, MMP9) were recognized as key therapeutic targets with excellent binding affinity screened by database analysis and molecular docking. The biological processes were identified by Gene Ontology (GO) enrichment, which appeared mainly involved in the positive regulation of cell proliferation as well as the negative regulation of apoptosis. The verification experiments in vitro revealed that fermented CS significantly attenuated the HG-induced cytotoxicity and apoptosis, and promoted the proliferation of HK-2 cells. Moreover, fermented CS significantly downregulated the expressions of Bax, Caspase-3, VEGFA, P-AKT and P-ERK, and upregulated the expression of PTEN compared with that of HG group.

CONCLUSION

Our results demonstrate that the fermented CS has nephroprotective effects significantly, which functions via promoting proliferation and inhibiting apoptosis of renal proximal tubular cells, likely by targeting Caspase-3, Bax, VEGFA and PTEN. Furthermore, AKT and ERK signaling pathway may be the critical mechanisms underlying the efficacy of fermented CS in DKD treatment.

Human Umbilical Cord Mesenchymal Stem Cells Inhibit Pyroptosis of Renal Tubular Epithelial Cells through miR-342-3p/Caspase1 Signaling Pathway in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the microvascular complications of diabetes. Recent studies suggest that the pyroptosis of renal tubular epithelial cell plays a critical role in DN. Currently, effective therapeutic strategies to counteract and reverse the progression of DN are lacking. Mesenchymal stem cells (MSCs) represent an attractive therapeutic tool for tissue damage and inflammation owing to their unique immunomodulatory properties. However, the underlying mechanisms remain largely unknown. In the present study, we found that human umbilical cord MSCs (UC-MSCs) can effectively ameliorate kidney damage and reduce inflammation in DN rats. Importantly, UC-MSC treatment inhibits inflammasome-mediated pyroptosis in DN. Mechanistically, we performed RNA sequencing and identified that miR-342-3p was significantly downregulated in the kidneys of DN rats. Furthermore, we found that miR-342-3p was negatively correlated with renal injury and pyroptosis in DN rats. The expression of miR-342-3p was significantly increased after UC-MSC treatment. Moreover, miR-342-3p decreased the expression of Caspase1 by targeting its 3 $\prime$ -UTR, which was confirmed by double-luciferase assay. Using miRNA mimic transfection, we demonstrated that UC-MSC-derived miR-342-3p inhibited pyroptosis of renal tubular epithelial cells through targeting the NLRP3/Caspase1 pathway. These findings would provide a novel intervention strategy for the use of miRNA-modified cell therapy for kidney diseases.

Increased Renal Medullary NOX-4 in Female but Not Male Mice during the Early Phase of Type 1 Diabetes: Potential Role of ROS in Upregulation of TGF-β1 and Fibronectin in Collecting Duct Cells

Chronic diabetes mellitus (DM) can lead to kidney damage associated with increased reactive oxygen species (ROS), proteinuria, and tubular damage. Altered protein expression levels of transforming growth factor-beta 1 (TGF-β1), fibronectin, and renal NADPH oxidase (NOX-4) are associated with the profibrotic phenotype in renal tubular cells. NOX-4 is one of the primary sources of ROS in the diabetic kidney and responsible for the induction of profibrotic factors in collecting duct (CD) cells. The renal medulla is predominantly composed of CDs; in DM, these CD cells are exposed to high glucose (HG) load. Currently there is no published literature describing the expression of these markers in the renal medulla in male and female mice during the early phase of DM, or the role of NOX-4-induced ROS. Our aim was to evaluate changes in transcripts and protein abundances of TGF-β1, fibronectin, and NOX-4 along with ROS levels in renal medullary tissues from male and female mice during a short period of streptozotocin (STZ)-induced type 1 DM and the effect of HG in cultured CD cells. CF-1 mice were injected with or without a single dose of STZ (200 mg/kg) and euthanized at day 6. STZ females showed higher expression of fibronectin and TGF-β1 when compared to control mice of either gender. Interestingly, STZ female mice showed a >30-fold increase on mRNA levels and a 3-fold increase in protein levels of kidney medullary NOX-4. Both male and female STZ mice showed increased intrarenal ROS. In primary cultures of inner medullary CD cells exposed to HG over 48 h, the expression of TGF-β1, fibronectin, and NOX-4 were augmented. M-1 CD cells exposed to HG showed increased ROS, fibronectin, and TGF-β1; this effect was prevented by NOX-4 inhibition. Our data suggest that at as early as 6 days of STZ-induced DM, the expression of profibrotic markers TGF-β1 and fibronectin increases in renal medullary CD cells. Antioxidants mechanisms in male and female in renal medullary tissues seems to be differentially regulated by the actions of NOX-4.

Renoprotective Impacts of Inonotus obliquus Ethanol-Ethyl Acetate Extract on Combined Streptozotocin and Unilateral Nephrectomy-Induced Diabetic Nephropathy in Mice

Diabetes nephropathy (DN) is one of the most common causes of end stage renal disease (ESRD) globally. Medication options to stop or slow the progression of chronic renal disease (CKD) are limited, and patients with DN remain at a high risk of developing renal failure. Inonotus obliquus extracts (IOEs) of Chaga mushroom have been shown to have anti-glycemic, anti-hyperlipidemia, antioxidant, and anti-inflammatory effects against diabetes. In this study, we examined the potential renal protective role of an ethyl acetate layer after water-ethyl acetate separation from Inonotus obliquus ethanol crude extract (EtCE-EA) from Chaga mushrooms in diabetic nephropathy mice after preparation with 1/3 NT + STZ. Our data showed that treatment with EtCE-EA can effectively regulate blood glucose, albumin-creatinine ratio, serum creatinine, and blood urea nitrogen (BUN) levels, and it can improve the renal damage in 1/3 NT + STZ-induced CRF mice with an increase in concentration (100, 300, and 500 mg/kg). In the immunohistochemical staining test, EtCE-EA can effectively reduce the expression of TGF-β and α-SMA after induction according to the increase in the concentration (100 mg/kg, 300 mg/kg), thereby slowing down the degree of kidney damage. Our findings demonstrate that EtCE-EA could provide renal protection in diabetes nephropathy, possibly due to the decreased expression of transforming growth factor-β1 and α-smooth muscle actin.

Heterogeneity in Kidney Histology and Its Clinical Indicators in Type 2 Diabetes Mellitus: A Retrospective Study

The heterogeneous spectrum of kidney disease in diabetes ranges from albuminuric or non-albuminuric diabetic kidney disease to non-diabetic kidney diseases. Presumptive clinical diagnosis of diabetic kidney disease may lead to an erroneous diagnosis.

MATERIAL AND METHOD

We analyzed the clinical profile and kidney biopsy of a total of 66 type 2 diabetes patients. Based on kidney histology, they were divided into-Class I (Diabetic Nephropathy), Class II (Non-diabetic kidney disease), and Class III (Mixed lesion). Demographic data, clinical presentation, and laboratory values were collected and analyzed. This study tried to examine the heterogeneity in kidney disease, its clinical indicator, and the role of kidney biopsy in the diagnosis of kidney disease in diabetes.

RESULTS

Class I consisted of 36(54.5%), class II 17(25.8%), and class III 13(19.7%) patients. The commonest clinical presentation was nephrotic syndrome 33(50%) followed by chronic kidney disease 16(24.4%) and asymptomatic urinary abnormality 8(12.1%). Diabetic retinopathy (DR) was present in 27(41%) cases. DR was significantly higher in the class I patients (p < 0.05). Specificity and positive predictive values of DR for DN were 0.83 and 0.81, respectively (sensitivity 0.61; negative predictive values 0.64). The Association of the duration of diabetes and the level of proteinuria with DN was statistically not significant (p > 0.05). Idiopathic MN (6) and Amyloidosis (2) were the most common isolated NDKD; whereas diffuse proliferative glomerulonephritis (DPGN) (7) was the commonest NDKD in mixed disease. Another common form of NDKD in mixed disease was Thrombotic Microangiopathy (2) and IgA nephropathy (2). NDKD was observed in 5(18.5%) cases in presence of DR. We noted biopsy-proven DN even in 14(35.9%) cases without DR, in 4(50%) cases with microalbuminuria and 14(38.9%) cases with a short duration of diabetes.

CONCLUSION

Almost half (45%) of cases with atypical presentation have non-diabetic kidney disease (NDKD), though even among these cases with atypical presentation diabetic nephropathy (either alone or in mixed form) is commonly seen in 74.2% of cases. DN has been seen in a subset of cases without DR, with microalbuminuria, and with a short duration of diabetes. Clinical indicators were insensitive in distinguishing DN Vs NDKD. Hence, a kidney biopsy may be a potential tool for the accurate diagnosis of kidney disease.

RISK FACTORS FOR DIABETIC NEPHROPATHY IN DIABETES MELLITUS TYPE 1

OBJECTIVE

The aim: To find the risk factors of microalbuminuria and estimated Glomerular Filtration Rate (eGFR) in patients with type 1 diabetes mellitus.

PATIENTS AND METHODS

Materials and methods: One hundred ten patients of type 1 diabetes mellitus in this cross-sectional study at diabetic and endocrinology center in Al-Najaf during the period from September 2021 to March 2022. All patients were asked about sociodemographic characteristics (age, gender, smoking, duration of DM type1, family history of DM type1), measured (body mass index BMI, blood pressure) and laboratory investigations done to all patients (G.U.E, s. creatinine, lipid profile, HBA1C, calculated estimated Glomerular Filtration Rate (eGFR) and Spot Urine Albumin-Creatinine Ratio (ACR).

RESULTS

Results: Out of 110 patients, 62 male and 48 female, the mean age was (22±12). The patients with microalbuminuria (ACR ≥ 30 mg/g) show statistically significant with increase HBA1C, duration of DM type 1, total cholesterol (T.C), low density lipoprotein (LDL), triglycerides (TG) and family history of DM type 1, while there were not statistically significant with age, gender, smoking, BMI, eGFR, high density lipoprotein (HDL) and hypertension. Patients with eGFR<90mL/min/1.73m2 show statistically significant with increase HBA1C, duration of DM type1, LDL, TG, T.C, while significantly decrease in HDL and there were not statistically significant with age, gender, smoking, family history of DM type 1, BMI and hypertension.

CONCLUSION

Conclusions: The degree of glycemic control, duration of type1 (DM) and dyslipidemia were associated with increased microalbuminuria and reduced eGFR (nephropathy). Family history of DM type1 was risk factor for microalbuminuria.

Therapeutic Effect of Kidney Tubular Cells-Derived Conditioned Medium on the Expression of MicroRNA-377, MicroRNA-29a, Aquapurin-1, Biochemical, and Histopathological Parameters Following Diabetic Nephropathy Injury in Rats

Background

Diabetic nephropathy (DN) is a critical complication of diabetes mellitus. This study evaluates whether administration of conditioned medium from kidney tubular cells (KTCs-CM) has the ability to be efficacious as an alternative to cell-based therapy for DN.

Materials and Methods

CM of rabbit kidney tubular cells (RK13; KTCs) has been collected and after centrifugation, filtered with 0.2 filters. Four groups of rats have been utilized, including control, DN, DN treated with CM, and sham group. After diabetes induction by streptozotocin (50 mg/kg body weight) in rats, 0.8 ml of the CM was injected to each rat three times per day for 3 consecutive days. Then, 24-h urine protein, blood urea nitrogen (BUN), and serum creatinine (Scr) have been measured through detection kits. The histopathological effects of CM on kidneys were evaluated by periodic acid-Schiff staining and the expression of microRNAs (miRNAs) 29a and 377 by using the real-time polymerase chain reaction. The expression of aquapurin-1 (AQP1) protein was also examined by Western blotting.

Results

Intravenous injections of KTCs-CM significantly reduced the urine volume, protein 24-h, BUN, and Scr, decreased the miRNA-377, and increased miRNA-29a and AQP1 in DN treated with CM rats.

Conclusion

KTCs-CM may have the potential to prevent kidney injury from diabetes by regulating the microRNAs related to DN and improving the expression of AQP1.

Deficiency of CFB attenuates renal tubulointerstitial damage by inhibiting ceramide synthesis in diabetic kidney disease

Accumulating evidence suggests the pathogenic role of immunity and metabolism in diabetic kidney disease (DKD). Herein, we aimed to investigate the effect of complement factor B (CFB) on lipid metabolism in the development of DKD. We found that in patients with diabetic nephropathy, the staining of Bb, CFB, C3a, C5a, and C5b-9 was markedly elevated in renal tubulointerstitium. Cfb-knockout diabetic mice had substantially milder tubulointerstitial injury and less ceramide biosynthesis. The in vitro study demonstrated that cytokine secretion, endoplasmic reticulum stress, oxidative stress, and cell apoptosis were ameliorated in HK-2 cells transfected with siRNA of CFB under high-glucose conditions. Exogenous ceramide supplementation attenuated the protective effect of CFB knockdown in HK-2 cells, while inhibiting ceramide synthases (CERS) with fumonisin B1 in CFB-overexpressing cells rescued the cell injury. CFB knockdown could downregulate the expression of NF-κB p65, which initiates the transcription of CERS3. Furthermore, C3 knockdown abolished CFB-mediated cytokine secretion, NF-κB signaling activation, and subsequently ceramide biosynthesis. Thus, CFB deficiency inhibited activation of the complement alternative pathway and attenuated kidney damage in DKD, especially tubulointerstitial injury, by inhibiting the NF-κB signaling pathway, further blocking the transcription of CERS, which regulates the biosynthesis of ceramide. CFB may be a promising therapeutic target of DKD.

Effects of Portulaca oleracea L. (purslane) on the metabolic syndrome: A review

Metabolic syndrome (MetS) is defined as a disorder with multiple abnormalities, including obesity, high blood pressure, dyslipidemia, and high blood glucose. MetS is the best-known risk factor for type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and obesity. With the globally increasing prevalence of MetS and its related abnormalities, attention to safe and effective prevention and treatment of this complex disorder has been increased. In particular, most treatments have been devoted to using natural agents that could provide more reliable and effective medicinal products with fewer side effects. Portulaca oleracea L. (purslane) is an herb whose therapeutic properties could be found in some ancient medical books. Purslane has shown analgesic, antispasmodic, skeletal muscle relaxant, bronchodilator, antiasthmatic, anti-inflammatory, antiseptic, diuretic, antibacterial, antipyretic, and wound-healing properties. In addition, purslane's hypoglycemic and hypolipidemic properties have been reported in different studies. The positive effects of this plant include reducing stress oxidative and inflammation along with the atherogenic index, improving insulin level and glucose uptake, decreasing lipid profiles, and ameliorating weight gain. These activities could reduce MetS complications. This review aims to provide a comprehensive overview of various in vitro, animal, and human studies regarding the effect of Portulaca oleracea on metabolic syndrome to better understand the underlying mechanisms of action for designing more effective treatments.

The effect of quercetin on diabetic nephropathy (DN): a systematic review and meta-analysis of animal studies

Quercetin, a flavonoid possessing numerous biological activities, is reported to improve renal injury in diabetic animals. Here, the aim of this systematic review and meta-analysis is to assess the effect of quercetin on diabetic nephropathy and summarize its possible mechanisms. We searched in four databases PubMed, Web of Sciences (WOS), Cochrane and Embase from inception to May 2021 and ultimately included 20 animal studies in this review. A total of 12 outcome measurements including renal function indexes, oxidative stress biomarkers and inflammatory cytokines were extracted for meta-analysis using RevMan 5.4 software. Apart from creatinine clearance and uric acid with no significant difference, quercetin significantly decreased the levels of renal index, serum/plasma creatinine (SCr), blood urea nitrogen (BUN), urine protein, urine albumin, malondialdehyde (MDA), tumor necrosis factor (TNF)-α and interleukin (IL)-1β, and increased superoxide dismutase (SOD) and catalase (CAT) activity. In short, quercetin improves renal function and attenuates the renal oxidative stress level and inflammatory response in DN animal models. Its possible action mechanisms include anti-oxidation, anti-inflammation, anti-fibrosis, and regulation of renal lipid accumulation.

Alterations in Protein Translation and Carboxylic Acid Catabolic Processes in Diabetic Kidney Disease

Diabetic kidney disease (DKD) remains the leading cause of end-stage kidney disease despite decades of study. Alterations in the glomerulus and kidney tubules both contribute to the pathogenesis of DKD although the majority of investigative efforts have focused on the glomerulus. We sought to examine the differential expression signature of human DKD in the glomerulus and proximal tubule and corroborate our findings in the db/db mouse model of diabetes. A transcriptogram network analysis of RNAseq data from laser microdissected (LMD) human glomerulus and proximal tubule of DKD and reference nephrectomy samples revealed enriched pathways including rhodopsin-like receptors, olfactory signaling, and ribosome (protein translation) in the proximal tubule of human DKD biopsy samples. The translation pathway was also enriched in the glomerulus. Increased translation in diabetic kidneys was validated using polyribosomal profiling in the db/db mouse model of diabetes. Using single nuclear RNA sequencing (snRNAseq) of kidneys from db/db mice, we prioritized additional pathways identified in human DKD. The top overlapping pathway identified in the murine snRNAseq proximal tubule clusters and the human LMD proximal tubule compartment was carboxylic acid catabolism. Using ultra-performance liquid chromatography–mass spectrometry, the fatty acid catabolism pathway was also found to be dysregulated in the db/db mouse model. The Acetyl-CoA metabolite was down-regulated in db/db mice, aligning with the human differential expression of the genes ACOX1 and ACACB. In summary, our findings demonstrate that proximal tubular alterations in protein translation and carboxylic acid catabolism are key features in both human and murine DKD.

The roles of mesenchymal stem cell-derived exosomes in diabetes mellitus and its related complications

Diabetes mellitus is a type of metabolic disease characterized by hyperglycemia, primarily caused by defects in insulin secretion, insulin action, or both. Long-term chronic hyperglycemia can lead to diabetes-related complications, causing damage, dysfunction, and failure of different organs. However, traditional insulin and oral drug therapy can only treat the symptoms but not delay the progressive failure of pancreatic beta cells or prevent the emergence of diabetic complications. Mesenchymal stem cells have received extensive attention due to their strong immunoregulatory functions and regeneration effects. Mesenchymal stem cell-derived exosomes (MSC-Exos) have been proposed as a novel treatment for diabetic patients as they have demonstrated superior efficiency to mesenchymal stem cells. This review summarizes the therapeutic effects, mechanisms, challenges, and future prospects of MSC-Exos in treating diabetes mellitus and its related complications. This review supports the potential use of MSC-Exos in future regenerative medicine to overcome the current difficulties in clinical treatment, particularly in treating diabetes.

Melatonin alleviates renal injury by activating mitophagy in diabetic nephropathy

Diabetic nephropathy (DN) causes serious renal tubule and interstitial damage, but effective prevention and treatment measures are lacking. Abnormal mitophagy may be involved in the progression of DN, but its upstream and downstream regulatory mechanisms remain unclear. Melatonin, a pineal hormone associated with circadian rhythms, is involved in regulating mitochondrial homeostasis. Here, we demonstrated abnormal mitophagy in the kidneys of DN mice or high glucose (HG)-treated HK-2 cells, which was accompanied by increased oxidative stress and inflammation. At the same time, the melatonin treatment alleviated kidney damage. After mitochondrial isolation, we found that melatonin promoted AMPK phosphorylation and accelerated the translocation of PINK1 and Parkin to the mitochondria, thereby activating mitophagy, reducing oxidative stress, and inhibiting inflammation. Interestingly, the renal protective effect of melatonin can be partially blocked by downregulation of PINK1 and inhibition of AMPK. Our studies demonstrated for the first time that melatonin plays a protective role in DN through the AMPK-PINK1-mitophagy pathway.

Clinical and Pathological Features of Chinese Patients with Type 2 Diabetes, Biopsy-Proven Diabetic Kidney Disease, and Rapid eGFR Decline

OBJECTIVE

The rate of kidney function decline in patients with diabetic kidney disease (DKD) is known to differ. This study analyzed the clinicopathologic features and related risk factors affecting long-term renal survival in Chinese type 2 diabetic patients with rapid estimated glomerular filtration rate (eGFR) decline.

METHODS

In this retrospective descriptive study, 191 DKD patients were first classified as rapid eGFR decliners and slow eGFR decliners on the basis of the median eGFR slope value (-8.0 mL/min/1.73 m²/year). In total, 96 patients with rapid eGFR decline were included in the analyses and subsequently allocated to end-stage renal disease (ESRD) and non-ESRD groups. Baseline clinicopathological data of rapid eGFR decliners were collected. Cox proportional hazard analysis was performed to calculate the hazard ratios (HRs) for progression to ESRD.

RESULTS

During a median follow-up of 25 months, 52 (54.2%) rapid eGFR decliners progressed to ESRD. These 52 rapid eGFR decliners had poorer renal function, lower hemoglobin and albumin concentrations, higher total cholesterol and baseline proteinuria levels, and more severe interstitial inflammation than those who did not progress to ESRD. After adjustment for age, gender, baseline eGFR, proteinuria, hemoglobin level, serum albumin concentration, and histopathologic parameters, multivariate Cox proportional hazard analysis revealed that eGFR (HR 0.973, 95% CI 0.956-0.989) and proteinuria (HR 1.125, 95% CI 1.030-1.228) were associated with the increased risk of progression to ESRD.

CONCLUSION

Higher proteinuria and lower eGFR were independent risk factors for renal progression in Chinese patients with type 2 diabetes and rapid eGFR decline.

Effects of Exosomes Derived from Kidney Tubular Cells on Diabetic Nephropathy in Rats

OBJECTIVE

One of the severe complications and well-known sources of end stage renal disease (ESRD) from diabetes mellitus is diabetic nephropathy (DN). Exosomes secreted from diverse cells are one of the novel encouraging therapies for chronic renal injuries. In this study, we assess whether extracted exosomes from kidney tubular cells (KTCs) could prevent early stage DN in vivo.

MATERIALS AND METHODS

In this experimental, exosomes from conditioned medium of rabbit KTCs (RK13) were purified by ultracentrifuge procedures. The exosomes were assessed in terms of morphology and size, and particular biomarkers were evaluated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Western blot, atomic force microscopy (AFM) and Zetasizer Nano analysis. The rats were divided into four groups: DN, control, DN treated with exosomes and sham. First, diabetes was induced in the rats by intraperitoneial (i.p.) administration of streptozotocin (STZ, 50 mg/kg body weight). Then, the exosomes were injected each week into their tail vein for six weeks. We measured 24-hour urine protein, blood urea nitrogen (BUN), and serum creatinine (Scr) levels with detection kits. The histopathological effects of the exosomes on kidneys were evaluated by periodic acid-Schiff (PAS) staining and expressions of miRNA-29a and miRNA-377 by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The KTC-Exos were approximately 50-150 nm and had a spherical morphology. They expressed the CD9 and CD63 specific markers. Intravenous injections of KTC-Exos potentially reduced urine volume (P<0.0001), and 24- hour protein (P<0.01), BUN (P<0.001) and Scr (P<0.0001) levels. There was a decrease in miRNA-377 (P<0.01) and increase in miRNA-29a (P<0.001) in the diabetic rats. KTC-Exos ameliorated the renal histopathology with regulatory changes in microRNAs (miRNA) expressions.

CONCLUSION

KTC-Exos plays a role in attenuation of kidney injury from diabetes by regulating the miRNAs associated with DN.

Systemic immune-inflammation index is associated with diabetic kidney disease in Type 2 diabetes mellitus patients: Evidence from NHANES 2011-2018

OBJECTIVE

Diabetic kidney disease (DKD) is the most common chronic kidney disease (CKD) and has the highest prevalence of end-stage kidney disease (ESKD) globally, owing mostly to the rise in Type 2 diabetes mellitus (T2DM) correlated with obesity. Current research suggested that the immune response and inflammation may play a role in the pathophysiology of T2DM. The systemic immune-inflammation index (SII) is a novel and integrated inflammatory biomarker that has not yet been linked to DKD. We aimed to identify the potential relationship between SII and DKD.

METHODS

In the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2018, the current cross-sectional study was conducted among adults with T2DM. SII was calculated as the platelet count × neutrophil count/lymphocyte count. DKD was diagnosed with impaired glomerular filtration rate (< 60 mL/min/1.73 m² assessed by using the Chronic Kidney Disease Epidemiology Collaboration algorithm), albuminuria (urine albumin to creatinine ratio ≥ 30 mg/g), or both in T2DM patients. To investigate the independent association between SII and DKD, weighted univariate and multivariable logistic regression analyses and subgroup analyses were performed.

RESULTS

The study involved 3937 patients in total, of whom 1510 (38.4%) had DKD for the diagnosis. After adjustment for covariates, multivariable logistic regression revealed that a high SII level was associated with increased likelihood of DKD (OR = 1.42, 95% CI: 1.10-1.83, P = 0.01). Subgroup analyses and interaction tests revealed that age, gender, estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio (ACR), body mass index (BMI), hypertension, hyperlipidemia, anti-inflammation therapy (yes or no), metformin use (yes or no), and insulin use (yes or no) had no significant dependence on this positive relationship (all p for interaction >0.05).

CONCLUSIONS

Our results indicate that the higher SII level is associated with DKD in T2DM patients. The SII could be a cost-effective and straightforward approach to detecting DKD. This needs to be verified in further prospective investigations.

MORG1—A Negative Modulator of Renal Lipid Metabolism in Murine Diabetes

Renal fatty acid (FA) metabolism is severely altered in type 1 and 2 diabetes mellitus (T1DM and T2DM). Increasing evidence suggests that altered lipid metabolism is linked to tubulointerstitial fibrosis (TIF). Our previous work has demonstrated that mice with reduced MORG1 expression, a scaffold protein in HIF and ERK signaling, are protected against TIF in the db/db mouse model. Renal TGF-ß1 expression and EMT-like changes were reduced in mice with single-allele deficiency of MORG1. Given the well-known role of HIF and ERK signaling in metabolic regulation, here we examined whether protection was also associated with a restoration of lipid metabolism. Despite similar features of TIF in T1DM and T2DM, diabetes-associated changes in renal lipid metabolism differ between both diseases. We found that de novo synthesis of FA/cholesterol and β-oxidation were more strongly disrupted in T1DM, whereas pathological fat uptake into tubular cells mediates lipotoxicity in T2DM. Thus, diminished MORG1 expression exerts renoprotection in the diabetic nephropathy by modulating important factors of TIF and lipid dysregulation to a variable extent in T1DM and T2DM. Prospectively, targeting MORG1 appears to be a promising strategy to reduce lipid metabolic alterations in diabetic nephropathy.

DNA methylation profiling identifies epigenetic differences between early versus late stages of diabetic chronic kidney disease

BACKGROUND

We investigated a cross-sectional epigenome-wide association study of patients with early and late diabetes-associated chronic kidney disease (CKD) to identify possible epigenetic differences between the two groups as well as changes in methylation across all stages of diabetic CKD. We also evaluated the potential of using a panel of identified 5'-C-phosphate-G-3' (CpG) sites from this cohort to predict the progression of diabetic CKD.

METHODS

This cross-sectional study recruited 119 adults. DNA was extracted from blood using the Qiagen QIAampDNA Mini Spin Kit. Genome-wide methylation analysis was performed using Illumina Infinium MethylationEPIC BeadChips (HM850K). Intensity data files were processed and analysed using the minfi and MissMethyl packages for R. We examined the degree of methylation of CpG sites in early versus late diabetic CKD patients for CpG sites with an unadjusted P-value <0.01 and an absolute change in methylation of 5% (n = 239 CpG sites).

RESULTS

Hierarchical clustering of the 239 CpG sites largely separated the two groups. A heat map for all 239 CpG sites demonstrated distinct methylation patterns in the early versus late groups, with CpG sites showing evidence of progressive change. Based on our differentially methylated region (DMR) analysis of the 239 CpG sites, we highlighted two DMRs, namely the cysteine-rich secretory protein 2 (CRISP2) and piwi-like RNA-mediated gene silencing 1 (PIWIL1) genes. The best predictability for the two groups involved a receiver operating characteristics curve of eight CpG sites alone and achieved an area under the curve of 0.976.

CONCLUSIONS

We have identified distinct DNA methylation patterns between early and late diabetic CKD patients as well as demonstrated novel findings of potential progressive methylation changes across all stages (1-5) of diabetic CKD at specific CpG sites. We have also identified associated genes CRISP2 and PIWIL1, which may have the potential to act as stage-specific diabetes-associated CKD markers, and showed that the use of a panel of eight identified CpG sites alone helps to increase the predictability for the two groups.

AMPK agonist alleviate renal tubulointerstitial fibrosis via activating mitophagy in high fat and streptozotocin induced diabetic mice

Renal tubulointerstitial fibrosis was a crucial pathological feature of diabetic nephropathy (DN), and renal tubular injury might associate with abnormal mitophagy. In this study, we investigated the effects and molecular mechanisms of AMPK agonist metformin on mitophagy and cellular injury in renal tubular cell under diabetic condition. The high fat diet (HFD) and streptozotocin (STZ)-induced type 2 diabetic mice model and HK-2 cells were used in this study. Metformin was administered in the drinking water (200 mg/kg/d) for 24 weeks. Renal tubulointerstitial lesions, oxidative stress and some indicators of mitophagy (e.g., LC3II, Pink1, and Parkin) were examined both in renal tissue and HK-2 cells. Additionally, compound C (an AMPK inhibitor) and Pink1 siRNA were applied to explore the molecular regulation mechanism of metformin on mitophagy. We found that the expression of p-AMPK, Pink1, Parkin, LC3II, and Atg5 in renal tissue of diabetic mice was decreased obviously. Metformin reduced the levels of serum creatinine, urine protein, and attenuated renal oxidative injury and fibrosis in HFD/STZ induced diabetic mice. In addition, Metformin reversed mitophagy dysfunction and the over-expression of NLRP3. In vitro pretreatment of HK-2 cells with AMPK inhibitor compound C or Pink1 siRNA negated the beneficial effects of metformin. Furthermore, we noted that metformin activated p-AMPK and promoted the translocation of Pink1 from the cytoplasm to mitochondria, then promoted the occurrence of mitophagy in HK-2 cells under HG/HFA ambience. Our results suggested for the first time that AMPK agonist metformin ameliorated renal oxidative stress and tubulointerstitial fibrosis in HFD/STZ-induced diabetic mice via activating mitophagy through a p-AMPK-Pink1-Parkin pathway.

Characterizing predictors of non-diabetic kidney disease (NDKD) in diabetic patients

BACKGROUND

Diabetic kidney disease (DKD) is the chief cause of renal involvement in diabetic patients. It is primarily a clinical diagnosis. Non-diabetic kidney disease (NDKD) may be missed if they are not biopsied. In this study, we describe the spectrum of NDKD and evaluate the predictors considered for planning a biopsy in diabetic patients with kidney disease.

METHODS

In a retrospective cohort study, diabetic patients who underwent kidney biopsy at our centre between May 2006 and July 2019 were evaluated for NDKD.

RESULTS

321 diabetic patients who underwent kidney biopsy were analyzed. Mean age was 49.3 ± 12.4 years and 71% were males. 75.8% patients had hypertension and 25.2% had diabetic retinopathy. Based on the kidney biopsy, patients were classified as DKD-127 (39.6%), NDKD-179(55.8%) and combined DKD + NDKD-15(4.7%). Overall, the most commonly diagnosed pathology was membranous nephropathy-MN (17%), followed by IgA nephropathy (16.0%) and focal segmental glomerulosclerosis-FSGS (14.9%). In patients with DKD + NDKD, IgA nephropathy (53.3%) was predominant. 165 (51.4%) patients had a diagnosis potentially amenable to a specific therapy. On multivariate analysis, female gender [OR 2.07 (1.08-3.97), p = 0.02], absence of diabetic retinopathy [OR 7.47 (3.71-15), p < 0.001] absence of hypertension [OR 3.17 (1.56-6.45), p = 0.001] and duration of diabetes ≤ 24 months [OR 3.67(1.97-6.84), p < 0.001], were independent predictors for NDKD while the absence of nephrotic range proteinuria [OR 1.73 (0.98-3.05), p 0.05] showed a trend towards significance.

CONCLUSION

Astute use of kidney biopsy can detect potentially treatable NDKD in a large number of diabetic patients with glomerular diseases being the predominant diagnosis. A combination of risk factors needs to be considered to guide the need for kidney biopsy in diabetic patients.

Serum adenosine deaminase levels are associated with diabetic kidney disease in type 2 diabetic patients

The aim of the present study was to evaluate the association between adenosine deaminase (ADA) levels and diabetic kidney disease (DKD) in patients with type 2 diabetes (T2D). In this study, patients with T2D who had been screened for DKD were recruited. Patients with an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 or a urinary albumin-to-creatinine ratio (UACR) ≥ 30 mg/g for 3 months were identified as having DKD. The prevalence of DKD was 13.3%, and the range of serum ADA levels was 4-37 U/L. Serum ADA levels were positively associated with cystatin C levels and UACR (r = 0.295 and r = 0.302, respectively, both P < 0.05) and negatively associated with eGFR (r = -0.342, P < 0.05). The proportion of participants with DKD increased significantly from 3.8% in the first tertile (T1) to 13.6% in the second tertile (T2) and 25.9% in the third tertile (T3) of ADA (P for trend < 0.001). After adjusting for clinical risk factors for DKD via multiple logistic regression, the corresponding odds ratios (ORs) of DKD for the participants in T2 and T3 vs those in T1 of ADA were 5.123 (1.282-20.474) and 10.098 (1.660-61.431), respectively. Receiver operating characteristic (ROC) analysis revealed that the optimal cutoff value of ADA to indicate DKD was 10 U/L. Its corresponding sensitivity and specificity were 75.5 and 56.4%, respectively. Our results demonstrated that serum ADA levels were closely associated with DKD and partly reflect the risk of DKD in patients with T2D.

Overexpression of mm9_circ_013935 alleviates renal inflammation and fibrosis in diabetic nephropathy via the miR-153-3p/NFIC axis

BACKGROUND

Circ-RBM4 (mm9_circ_013935) has been revealed to be low-expressed in the renal tissues of diabetic nephropathy (DN) mice while its underlying regulatory mechanism remains unexplored.

METHODS

The high glucose (HG)-treated mouse podocytes were used to establish the DN cell models. A CCK-8 assay was used to examine the viability of mouse podocytes. The expression of proteins related to fibrosis (Collagen I, Collagen III, fibronectin) was detected using western blot. The concentration of inflammation cytokines (TNF-α, IL-1β, IL-8) in mouse podocytes was assessed by ELISA. The interaction between genes was explored by luciferase reporter assays.

RESULTS

HG treatement decreased the viability and elevated the expression of fibrosis and inflammation factors in mouse podocytes. Circ-RBM4 expression was downregulated in HG-treated mouse podocytes. Circ-RBM4 overexpression reversed HG-induced increase in levels of proteins related to fibrosis and the concentration of inflammation factors. MiR-153-3p was revealed to bind with circ-RBM4 and directly targeted nuclear factor I/C (NFIC) in mouse podocytes. Rescue assays indicated that circ-RBM4 attenuated HG-induced fibrosis and inflammation response in mouse podocytes by inhibiting miR-153-3p expression or upregulating NFIC expression.

CONCLUSION

Circ-RBM4 alleviated the renal inflamation and renal fibrosis in DN by targeting the miR-153-3p/NFIC axis.

Pleiotropic Effects of Sodium-Glucose Cotransporter-2 Inhibitors: Renoprotective Mechanisms beyond Glycemic Control

Diabetes mellitus is a major cause of chronic kidney disease and end-stage renal disease. However, the management of chronic kidney disease, particularly diabetes, requires vast improvements. Recently, sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally developed for the treatment of diabetes, have been shown to protect against kidney injury via glycemic control, as well as various other mechanisms, including blood pressure and hemodynamic regulation, protection from lipotoxicity, and uric acid control. As such, regulation of these mechanisms is recommended as an effective multidisciplinary approach for the treatment of diabetic patients with kidney disease. Thus, SGLT2 inhibitors are expected to become key drugs for treating diabetic kidney disease. This review summarizes the recent clinical evidence pertaining to SGLT2 inhibitors as well as the mechanisms underlying their renoprotective effects. Hence, the information contained herein will advance the current understanding regarding the pleiotropic effects of SGLT2 inhibitors, while promoting future research in the field.

Transcription of MRPL12 regulated by Nrf2 contributes to the mitochondrial dysfunction in diabetic kidney disease

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Increasing evidences suggested that DKD correlates more closely to mitochondrial dysfunction than to hyperglycemia. Our previous study has reported that mitochondrial ribosomal protein L7/L12 (MRPL12) could positively control the mitochondrial oxidative phosphorylation (OXPHOS) and mtDNA copy number. The present study further investigated the role of MRPL12 in mitochondrial dysfunction of DKD. Using a mass spectrometry-based proteomics and immunohistochemistry, we found that MRPL12 underwent significant decreases in diabetic kidneys. Moreover, decreased expression of MRPL12 was associated with reduced mitochondrial OXPHOS in proximal tubular epithelial cells (PTECs) and overexpression of MRPL12 could alleviated the impairment of OXPHOS induced by long term high glucose. We further explored the upstream mechanism and identified nuclear factor erythroid 2-related factor 2 (Nrf2) as a potential transcription factor for MRPL12. Nrf2 changes consistently with MRPL12 in DKD and correlates with alterations of mitochondrial function, fibrosis and apoptosis of PTECs treated with high glucose challenge. Thus, the role of MRPL12 in the maintenance of mitochondrial function in DKD may be regulated by Nrf2, and provides new potential therapeutic targets for DKD.

General Control of Amino Acid Synthesis 5-Like 1-Mediated Acetylation of Manganese Superoxide Dismutase Regulates Oxidative Stress in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the major cause of end-stage renal disease (ESRD). In the past few decades, there has been a large amount of evidence to highlight the pivotal role of oxidative stress in the development and progression of DKD. However, the detailed molecular mechanisms are not fully elucidated. A new sight has been established that the mitochondrial acetyltransferase GCN5L1 participates in cellular redox homeostasis maintenance in DKD. Firstly, we found that the expression of GCN5L1 is significantly elevated both in human and mouse kidney tissues with DKD and in hyperglycemic renal tubular epithelial cells (TECs), while deletion of GCN5L1 could effectively ameliorate oxidative stress-induced renal injury in DKD. Furthermore, deletion of GCN5L1 could reduce MnSOD acetylation on lysine 68 and activate its activity, thereby scavenging excessive ROS and relieving oxidative stress-induced renal inflammation and fibrosis. In general, GCN5L1-mediated acetylation of MnSOD exacerbated oxidative stress-induced renal injury, suggesting that GCN5L1 might be a potential intervention target in DKD.

EHR2CCAS: A framework for mapping EHR to disease knowledge presenting causal chain of disorders - chronic kidney disease example

OBJECTIVE

The goal of this work was to capture diseases in patients by comprehending the fine-grained medical conditions and disease progression manifested by transitions in medical conditions. We realize this by introducing our earlier work on a state-of-the-art knowledge presentation, which defines a disease as a causal chain of abnormal states (CCAS). Here, we propose a framework, EHR2CCAS, for constructing a system to map electronic health record (EHR) data to CCAS.

MATERIALS AND METHODS

EHR2CCAS is a framework consisting of modules that access heterogeneous EHR to estimate the presence of abnormal states in a CCAS for a patient in a given time window. EHR2CCAS applies expert-driven (rule-based) and data-driven (machine learning) methods to identify abnormal states from structured and unstructured EHR data. It features data-driven approaches for unlocking clinical texts and imputations based on the EHR temporal properties and the causal CCAS structure. This study presents the CCAS of chronic kidney disease as an example. A mapping system between the EHR from the University of Tokyo Hospital and CCAS of chronic kidney disease was constructed and evaluated against expert annotation.

RESULTS

The system achieved high prediction performance in identifying abnormal states that had strong agreement among annotators. Our handling of narrative varieties in texts and our imputation of the presence of an abnormal state markedly improved the prediction performance. EHR2CCAS presents patient data describing the temporal presence of abnormal states in CCAS, which is useful in individual disease progression management. Further analysis of the differentiation of transition among abnormal states outputted by EHR2CCAS can contribute to detecting disease subtypes.

CONCLUSION

This work represents the first step toward combining disease knowledge and EHR to extract abnormality related to a disease defined as fine-grained abnormal states and transitions among them. This can aid in disease progression management and deep phenotyping.

Fibrinogen to Albumin Ratio as an Independent Risk Factor for Type 2 Diabetic Kidney Disease

PURPOSE

Diabetic kidney disease (DKD) is an inflammatory disease. This study aimed to investigate the association of fibrinogen to albumin ratio (FAR) with DKD.

PATIENTS AND METHODS

A total of 1022 type 2 diabetes mellitus (T2DM) patients with DKD and 1203 T2DM patients without DKD were enrolled in this study. Laboratory values including blood cell count, hemoglobin A1c, biochemical parameters, and fibrinogen and albumin creatinine ratio were recorded. Patients were classified according to tertile of admission FAR. Clinical parameters were compared between groups. Logistic regression, linear regression, ROC analysis and spline regression were carried out.

RESULTS

FAR in the DKD group was significantly higher than that in the non-DKD group. FAR had the highest odds ratio as an independent risk factor for the development of DKD and the highest area under ROC curve for predicting DKD compared with albumin (ALB) or fibrinogen (FIB) alone. Simple linear regression analyses revealed a significant and linear correlation of FAR with neutrophil and neutrophil-to-lymphocyte ratio. FAR was an independent risk factor for development of DKD. Spline regression showed that there was a significant linear association between DKD incidence and continuous FAR value when it exceeded 67.3mg/g.

CONCLUSION

FAR is a stronger independent predictor of DKD than FIB and ALB. FAR is an independent risk factor for DKD development when it exceeded 67.3mg/g. FAR might be one of novel diagnostic biomarkers to predict and prevent DKD progression. However, a prospective study to validate the prognostic model is still needed.

Gut Microbiome Composition Remains Stable in Individuals with Diabetes-Related Early to Late Stage Chronic Kidney Disease

(1) Background: Individuals with diabetes and chronic kidney disease display gut dysbiosis when compared to healthy controls. However, it is unknown whether there is a change in dysbiosis across the stages of diabetic chronic kidney disease. We investigated a cross-sectional study of patients with early and late diabetes associated chronic kidney disease to identify possible microbial differences between these two groups and across each of the stages of diabetic chronic kidney disease. (2) Methods: This cross-sectional study recruited 95 adults. DNA extracted from collected stool samples were used for 16S rRNA sequencing to identify the bacterial community in the gut. (3) Results: The phylum Firmicutes was the most abundant and its mean relative abundance was similar in the early and late chronic kidney disease group, 45.99 ± 0.58% and 49.39 ± 0.55%, respectively. The mean relative abundance for family Bacteroidaceae, was also similar in the early and late group, 29.15 ± 2.02% and 29.16 ± 1.70%, respectively. The lower abundance of Prevotellaceae remained similar across both the early 3.87 ± 1.66% and late 3.36 ± 0.98% diabetic chronic kidney disease groups. (4) Conclusions: The data arising from our cohort of individuals with diabetes associated chronic kidney disease show a predominance of phyla Firmicutes and Bacteroidetes. The families Ruminococcaceae and Bacteroidaceae represent the highest abundance, while the beneficial Prevotellaceae family were reduced in abundance. The most interesting observation is that the relative abundance of these gut microbes does not change across the early and late stages of diabetic chronic kidney disease, suggesting that this is an early event in the development of diabetes associated chronic kidney disease. We hypothesise that the dysbiotic microbiome acquired during the early stages of diabetic chronic kidney disease remains relatively stable and is only one of many risk factors that influence progressive kidney dysfunction.

YAP Activation in Renal Proximal Tubule Cells Drives Diabetic Renal Interstitial Fibrogenesis

An increasing number of studies suggest that the renal proximal tubule is a site of injury in diabetic nephropathy (DN), and progressive renal tubulointerstitial fibrosis is an important mediator of progressive kidney dysfunction in DN. In this study, we observed increased expression and activation of YAP (yes-associated protein) in renal proximal tubule epithelial cells (RPTC) in patients with diabetes and in mouse kidneys. Inducible deletion of Yap specifically in RPTC or administration of the YAP inhibitor verteporfin significantly attenuated diabetic tubulointerstitial fibrosis. EGFR-dependent activation of RhoA/Rock and PI3K-Akt signals and their reciprocal interaction were upstream of proximal tubule YAP activation in diabetic kidneys. Production and release of CTGF in culture medium were significantly augmented in human embryonic kidney (HEK)-293 cells transfected with a constitutively active YAP mutant, and the conditioned medium collected from these cells activated and transduced fibroblasts into myofibroblasts. This study demonstrates that proximal tubule YAP-dependent paracrine mechanisms play an important role in diabetic interstitial fibrogenesis; therefore, targeting Hippo signaling may be a therapeutic strategy to prevent the development and progression of diabetic interstitial fibrogenesis.

Sex Differences in Diabetes- and TGF-β1-Induced Renal Damage

While females are less affected by non-diabetic kidney diseases compared to males, available data on sex differences in diabetic nephropathy (DN) are controversial. Although there is evidence for an imbalance of sex hormones in diabetes and hormone-dependent mechanisms in transforming growth factor β1 (TGF-β1) signaling, causes and consequences are still incompletely understood. Here we investigated the influence of sex hormones and sex-specific gene signatures in diabetes- and TGF-β1-induced renal damage using various complementary approaches (a db/db diabetes mouse model, ex vivo experiments on murine renal tissue, and experiments with a proximal tubular cell line TKPTS). Our results show that: (i) diabetes affects sex hormone concentrations and renal expression of their receptors in a sex-specific manner; (ii) sex, sex hormones and diabetic conditions influence differences in expression of TGF-β1, its receptor and bone morphogenetic protein 7 (BMP7); (iii) the sex and sex hormones, in combination with variable TGF-β1 doses, determine the net outcome in TGF-β1-induced expression of connective tissue growth factor (CTGF), a profibrotic cytokine. Altogether, these results suggest complex crosstalk between sex hormones, sex-dependent expression pattern and profibrotic signals for the precise course of DN development. Our data may help to better understand previous contradictory findings regarding sex differences in DN.

High sucrose diet induces morphological, structural and functional impairments in the renal tubules of Drosophila melanogaster: A model for studying type-2 diabetes mediated renal tubular dysfunction

Continuous feeding of high dietary sugar is strongly associated with type 2 diabetes (T2D) and its secondary complications. Diabetic nephropathy (DN) is a major secondary complication that leads to glomerular and renal tubular dysfunction. The present study is aimed to investigate the effects of chronic exposure of high sugar diet (HSD) on renal tubules. Malpighian tubules (MTs), a renal organ of Drosophila, were used as a model in the study. Feeding of HSD develops T2D condition in Drosophila. The MTs showed structural abnormalities in 20 days of HSD fed flies. Impaired insulin signaling, oxidative stress, enhanced levels of AGE-RAGE and induction of apoptosis were observed in the MTs of these flies. Further, altered expression of transporters, enhanced uric acid level and reduced fluid secretion rate confirmed the impaired function of MTs in these flies. RNA-seq and RT-PCR analyses in the MTs of HSD fed-and control-flies revealed the altered expression of candidate genes that regulate several important pathways including extracellular matrix (ECM), advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE), transforming growth factor β (TGF-β), galactose, starch and sucrose metabolism that are well known mediators of renal tubular dysfunction in DN patients. Disruption of insulin signaling in the MTs also causes renal tubular dysfunction similar to HSD fed flies. Overall, the study suggests that phenotypes observed in the MTs of HSD fed flies recapitulate several hallmarks of renal tubular dysfunction in DN patients. Therefore, we conclude that MTs of HSD fed flies may be used for deciphering the underlying mechanisms of T2D mediated renal tubular dysfunction.

Human umbilical cord-derived mesenchymal stem cells prevent the progression of early diabetic nephropathy through inhibiting inflammation and fibrosis

Background

Diabetic nephropathy (DN) is one of the most serious complications of diabetes and the leading cause of end-stage chronic kidney disease. Currently, there are no effective drugs for treating DN. Therefore, novel and effective strategies to ameliorate DN at the early stage should be identified. This study aimed to explore the effectiveness and underlying mechanisms of human umbilical cord mesenchymal stem cells (UC-MSCs) in DN.

Methods

We identified the basic biological properties and examined the multilineage differentiation potential of UC-MSCs. Streptozotocin (STZ)-induced DN rats were infused with 2 × 10⁶ UC-MSCs via the tail vein at week 6. After 2 weeks, we measured blood glucose level, levels of renal function parameters in the blood and urine, and cytokine levels in the kidney and blood, and analyzed renal pathological changes after UC-MSC treatment. We also determined the colonization of UC-MSCs in the kidney with or without STZ injection. Moreover, in vitro experiments were performed to analyze cytokine levels of renal tubular epithelial cell lines (NRK-52E, HK2) and human renal glomerular endothelial cell line (hrGECs).

Results

UC-MSCs significantly ameliorated functional parameters, such as 24-h urinary protein, creatinine clearance rate, serum creatinine, urea nitrogen, and renal hypertrophy index. Pathological changes in the kidney were manifested by significant reductions in renal vacuole degeneration, inflammatory cell infiltration, and renal interstitial fibrosis after UC-MSC treatment. We observed that the number of UC-MSCs recruited to the injured kidneys was increased compared with the controls. UC-MSCs apparently reduced the levels of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) and pro-fibrotic factor (TGF-β) in the kidney and blood of DN rats. In vitro experiments showed that UC-MSC conditioned medium and UC-MSC-derived exosomes decreased the production of these cytokines in high glucose-injured renal tubular epithelial cells, and renal glomerular endothelial cells. Moreover, UC-MSCs secreted large amounts of growth factors including epidermal growth factor, fibroblast growth factor, hepatocyte growth factor, and vascular endothelial growth factor.

Conclusion

UC-MSCs can effectively improve the renal function, inhibit inflammation and fibrosis, and prevent its progression in a model of diabetes-induced chronic renal injury, indicating that UC-MSCs could be a promising treatment strategy for DN.