Pathogenesis of diabetic nephropathy

Impact of DPP-4 Inhibitors in Patients with Diabetes Mellitus and Heart Failure: An In-Depth Review

The increasing prevalence of both type 2 diabetes mellitus and heart failure has underscored the urgent need for optimized therapeutic strategies that address the complex interplay between these conditions. Dipeptidyl peptidase-4 (DPP-4) inhibitors have emerged as a popular class of glucose-lowering agents due to their favorable glycemic effects, safety profile, and potential cardiovascular benefits. However, the impact of DPP-4 inhibitors on heart failure outcomes in patients with diabetes remains contentious, with conflicting evidence from clinical trials and observational studies. This review critically examines current evidence on the use of DPP-4 inhibitors in patients with coexisting diabetes and heart failure, focusing on pharmacodynamics, safety, and efficacy outcomes. We explore the physiological mechanisms by which DPP-4 inhibitors may influence heart failure risk, including modulation of inflammation, oxidative stress, and myocardial fibrosis. Clinical trials such as SAVOR-TIMI 53, EXAMINE, and TECOS are evaluated to provide a comprehensive analysis of DPP-4 inhibitors' effects on hospitalization for heart failure, mortality, and cardiovascular events in diabetic patients. While some trials suggest an increased risk of HF hospitalizations with specific DPP-4 inhibitors (e.g., saxagliptin), others report neutral effects, raising questions about the class effects versus individual drug characteristics within this group. Additionally, we address discrepancies in outcomes related to patient demographics, HF phenotype, and comorbid conditions that may influence DPP-4 inhibitors' risk-benefit profile. Comparative insights into alternative glucose-lowering therapies such as SGLT2 inhibitors and GLP-1 receptor agonists are also provided, highlighting potential implications for treatment selection in this high-risk population. In summary, this review synthesizes available evidence on DPP-4 inhibitors' impact in diabetic patients with heart failure, aiming to guide clinicians in making informed therapeutic decisions. While DPP-4 inhibitors remain a viable option in diabetes management, caution is warranted in patients with advanced heart failure, and future research is essential to refine patient-specific guidelines.

Role of oxidative stress in diabetes-induced complications and their management with antioxidants

Diabetes mellitus (DM) is a huge global health issue and one of the most studied diseases, with a large global prevalence. Oxidative stress is a cytotoxic consequence of the excessive development of ROS and suppression of the antioxidant defense system for ROS elimination, which accelerates the progression of diabetes complications such as diabetic neuropathy, retinopathy, and nephropathy. Hyperglycaemia induced oxidative stress causes the activation of seven major pathways implicated in the pathogenesis of diabetic complications. These pathways increase the production of ROS and RNS, which contributes to dysregulated autophagy, gene expression changes, and the development of numerous pro-inflammatory mediators which may eventually lead to diabetic complications. This review will illustrate that oxidative stress plays a vital role in the pathogenesis of diabetic complications, and the use of antioxidants will help to reduce oxidative stress and thus may alleviate diabetic complications.

Corilagin alleviates podocyte injury in diabetic nephropathy by regulating autophagy via the SIRT1-AMPK pathway

BACKGROUND

Diabetic nephropathy (DN) is the most frequent chronic microvascular consequence of diabetes, and podocyte injury and malfunction are closely related to the development of DN. Studies have shown that corilagin (Cor) has hepatoprotective, anti-inflammatory, antibacterial, antioxidant, anti-hypertensive, anti-diabetic, and anti-tumor activities.

AIM

To explore the protective effect of Cor against podocyte injury in DN mice and the underlying mechanisms.

METHODS

Streptozotocin and a high-fat diet were combined to generate DN mice models, which were then divided into either a Cor group or a DN group (n = 8 in each group). Mice in the Cor group were intraperitoneally injected with Cor (30 mg/kg/d) for 12 wk, and mice in the DN group were treated with saline. Biochemical analysis was used to measure the blood lipid profiles. Hematoxylin and eosin staining was used to detect pathological changes in kidney tissue. Immunohistochemistry and Western blotting were used to assess the protein expression of nephrin and podocin. Mouse podocyte cells (MPC5) were cultured and treated with glucose (5 mmol/L), Cor (50 μM), high glucose (HG) (30 mmol/L), and HG (30 mmol/L) plus Cor (50 μM). Real-time quantitative PCR and Western blotting were performed to examine the effects of Cor on podocyte autophagy.

RESULTS

Compared with the control group, the DN mice models had increased fasting blood glucose, glycosylated hemoglobin, triglycerides, and total cholesterol, decreased nephrin and podocin expression, increased apoptosis rate, elevated inflammatory cytokines, and enhanced oxidative stress. All of the conditions mentioned above were alleviated after intervention with Cor. In addition, Cor therapy improved SIRT1 and AMPK expression (P < 0.001), inhibited reactive oxygen species and oxidative stress, and elevated autophagy in HG-induced podocytes (P < 0.01).

CONCLUSION

Cor alleviates podocyte injury by regulating autophagy via the SIRT1-AMPK pathway, thereby exerting its protective impact on renal function in DN mice.

Terpenes in the management of chronic kidney disease

Chronic kidney disease (CKD) is a chronic and progressive systemic condition that characterizes irreversible alterations in the kidneys' function and structure over an extended period, spanning months to years. CKD is the one of the major causes of mortality worldwide. However, very limited treatment options are available in the market for management of the CKD. Diabetes and hypertension are the key risk factors for the progression of CKD. It is majorly characterised by glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Plants are considered safe and effective in treating various chronic conditions. A diverse group of phytoconstituents, including polyphenols, flavonoids, alkaloids, tannins, saponins, and terpenes, have found significant benefits in managing chronic ailments. Terpenes constitute a diverse group of plant compounds with various therapeutic benefits. Evidence-based pharmacological studies underscore the crucial role played by terpenes in preventing and managing CKD. These substances demonstrate the capacity to hinder detrimental pathways, such as oxidative stress, inflammation and fibrosis, thereby demonstrating benefit in renal dysfunction. This review offers a comprehensive overview of the roles and positive attributes of commonly occurring terpenes in managing the causes and risk factors of CKD and the associated conditions.

Potential utilization of ferulic acid and its derivatives in the management of metabolic diseases and disorders: An insight into mechanisms

Metabolic diseases are abnormal conditions that impair the normal metabolic process, which involves converting food into energy at a cellular level, and cause difficulties like obesity and diabetes. The study aimed to investigate how ferulic acid (FA) and its derivatives could prevent different metabolic diseases and disorders and to understand the specific molecular mechanisms responsible for their therapeutic effects. Information regarding FA associations with metabolic diseases and disorders was compiled from different scientific search engines, including Science Direct, Wiley Online, PubMed, Scopus, Web of Science, Springer Link, and Google Scholar. This review revealed that FA exerts protective effects against metabolic diseases such as diabetes, diabetic retinopathy, neuropathy, nephropathy, cardiomyopathy, obesity, and diabetic hypertension, with beneficial effects on pancreatic cancer. Findings also indicated that FA improves insulin secretion by increasing Ca2+ influx through the L-type Ca2+ channel, thus aiding in diabetes management. Furthermore, FA regulates the activity of inflammatory cytokines (TNF-α, IL-18, and IL-1β) and antioxidant enzymes (CAT, SOD, and GSH-Px) and reduces oxidative stress and inflammation, which are common features of metabolic diseases. FA also affects various signaling pathways, including the MAPK/NF-κB pathways, which play an important role in the progression of diabetic neuropathy and other metabolic disorders. Additionally, FA regulates apoptosis markers (Bcl-2, Bax, and caspase-3) and exerts its protective effects on cellular destruction. In conclusion, FA and its derivatives may act as potential medications for the management of metabolic diseases.

Incidence and Predictors of Diabetic Nephropathy among Type 2 Diabetes Mellitus Patients, Southern Ethiopia

Background

Diabetic nephropathy is the most common cause of end-stage renal disease, and it brings high morbidity and mortality. Globally, the predominant rise in type II diabetes prevalence significantly increases the incidence of diabetic nephropathy. Therefore, timely diagnosis and prompt management of diabetic nephropathy and early identification of predictors are essential. Thus, this study aimed to determine the incidence and predictors of diabetic nephropathy among type II diabetes mellitus patients.

Methods

A retrospective follow-up study was conducted among 532 type II diabetes patients who enrolled at Hawassa University Comprehensive Specialized Hospital from January 1, 2012, to December 31, 2021. A simple random sampling technique was used to select the study participants. The extracted data were entered into EpiData version 3.1 and analyzed by Stata version 14. A bivariate and multivariable Cox proportional hazard regression analysis was fitted to identify predictors of diabetic nephropathy. The Cox proportional hazards assumption was checked using the Schoenfeld residual test, and the goodness of fit of the model was checked using the Cox-Snell residual test. An adjusted hazard ratio with a 95% confidence interval and P values were used to identify statistically significant predictors.

Results

The overall incidence rate of diabetic nephropathy was 2.71 cases (95% CI: 2.12, 3.47) per 1,000 person-months of observation. Age (AHR = 1.027; 95% CI = 1.005, 1.049), fasting blood sugar (AHR = 1.010; 95% CI = 1.007, 1.013), and systolic blood pressure (AHR = 1.050; 95% CI = 1.031,1.069) were significant positive predictors of diabetic nephropathy, whereas the duration of diabetes longer than five years (AHR = 0.20; 95% CI = 0.09, 0.44) was a protective predictor for the development of diabetic nephropathy.

Conclusion

The incidence rate of diabetic nephropathy was high. Age, fasting blood sugar, systolic blood pressure, and duration of diabetes were found to be independent predictors of diabetic nephropathy. To overcome this public health problem, prompt and effective strategies should be designed based on identified predictors to prevent the development of diabetic nephropathy.

Molecular mechanisms and therapeutic potential of natural flavonoids in diabetic nephropathy: Modulation of intracellular developmental signaling pathways

Recognized as a common microvascular complication of diabetes mellitus (DM), diabetic nephropathy (DN) is the principal cause of chronic end-stage renal disease (ESRD). Patients with diabetes have an approximately 25% risk of developing progressive renal disease. The underlying principles of DN control targets the dual outcomes of blood glucose regulation through sodium glucose cotransporter 2 (SGLT 2) blockade and hypertension management through renin-angiotensin-aldosterone inhibition. However, these treatments are ineffective in halting disease progression to kidney failure and cardiovascular comorbidities. Recently, the dysregulation of subcellular signaling pathways has been increasingly implicated in DN pathogenesis. Natural compounds are emerging as effective and side-effect-free therapeutic agents that target intracellular pathways. This narrative review synthesizes recent insights into the dysregulation of maintenance pathways in DN, drawing from animal and human studies. To compile this review, articles reporting DN signaling pathways and their treatment with natural flavonoids were collected from PubMed, Cochrane Library Web of Science, Google Scholar and EMBASE databases since 2000. As therapeutic interventions are frequently based on the results of clinical trials, a brief analysis of data from current phase II and III clinical trials on DN is discussed.

IL-17 in type II diabetes mellitus (T2DM) immunopathogenesis and complications; molecular approaches

Chronic inflammation has long been considered the characteristic feature of type II diabetes mellitus (T2DM) Immunopathogenesis. Pro-inflammatory cytokines are considered the central drivers of the inflammatory cascade leading to β-cell dysfunction and insulin resistance (IR), two major pathologic events contributing to T2DM. Analyzing the cytokine profile of T2DM patients has also introduced interleukin-17 (IL-17) as an upstream regulator of inflammation, regarding its role in inducing the nuclear factor-kappa B (NF-κB) pathway. In diabetic tissues, IL-17 induces the expression of inflammatory cytokines and chemokines. Hence, IL-17 can deteriorate insulin signaling and β-cell function by activating the JNK pathway and inducing infiltration of neutrophils into pancreatic islets, respectively. Additionally, higher levels of IL-17 expression in patients with diabetic complications compared to non-complicated individuals have also proposed a role for IL-17 in T2DM complications. Here, we highlight the role of IL-17 in the Immunopathogenesis of T2DM and corresponding pathways, recent advances in preclinical and clinical studies targeting IL-17 in T2DM, and corresponding challenges and possible solutions.

Association of KLOTHO gene variants with metabolic and renal function parameters in Mexican patients living with type 2 diabetes

Objective

Type 2 diabetes (T2D) and high blood pressure are the main causes of chronic kidney disease (CKD) in adulthood. Both metabolic and oxidative stresses driven by hyperglycemia as well as genetic factors have been suggested as pathogenic causes of renal failure. Some single nucleotide variants (SNVs) on gene coding KLOTHO (KL) have been implicated in several clinical scenarios including hypertension, diabetes, and cardiovascular disease. The aim of this study was to analyze the association of rs1207568 (-395G > A), rs953614 (+ 1062T > G) and rs564481 (+ 1818 C > T) SNVs with metabolic and renal function parameters in Mexican patients living with type 2 diabetes.

Methods

A cross-sectional study was conducted in 637 Mexican patients with T2D, and/or hypertension without previous diagnosis of CKD. Anthropometric, metabolic, and renal function parameters were determined. Patients were genotyped for rs1207568, rs953614 and rs564481 SNVs and associations under a dominant genetic model were analyzed by logistic regression.

Results

For rs9536314, G-allele showed to be protective for hypo-HDL-C, albuminuria, and CKD. Carriers of minor allele of rs564481 had low odds for high glucose levels. No differences in genotype nor allele frequencies between the patients and the reference population were observed.

Conclusion

In Mexican patients living with type 2 diabetes, KL variant rs9536314 was found associated with low odds of hypo-HDL cholesterol, albuminuria and presence of CKD. Meanwhile the consensus of soluble KLOTHO measurement is reached, genetic variants in the KL gene could be considered as genetic markers for CKD susceptibility in patients at high-risk of vascular complications.

The role of aetiology in cardiac manifestations of chronic kidney disease: the CPH-CKD ECHO study

PURPOSE

We investigated the associations between cardiac parameters and aetiologies of CKD in an exploratory study.

METHODS

The study population consisted of 883 participants, 174 controls and 709 patients with aetiologies of CKD including diabetic nephropathy/renovascular KD in diabetes mellitus, hypertensive/renovascular nephropathy, tubulointerstitial nephritis, glomerulonephritis/vasculitis, polycystic KD (PKD), and CKD of unknown origin. Echocardiographic measures included left ventricular (LV) ejection fraction, global longitudinal, area, and radial strain, E/e' ratio, and LV mass index. These were compared between each aetiological group and controls in unadjusted and adjusted analysis.

RESULTS

In unadjusted analysis, patients with diabetic nephropathy/renovascular KD in diabetes mellitus, had impaired LV ejection fraction (Median [IQR]: 56% [49.9,60.69] vs. 60.8% [57.7,64.1]), global longitudinal (mean ± SD: 13.1 ± 3.5% vs. 15.5 ± 2.6%), area (24.1 ± 5.8% vs. 28.5 ± 4.2%), and radial strain (36.2 ± 11.2% vs. 44.1 ± 9.7%), and increased LV mass index (89.1 g/m2 [71.8,104.9] vs. 69,0 g/m2 [57.9,80.8]) and E/e' ratio (10.6 [8.5,12.6] vs. 7 [5.8,8.3], p < 0.001 for all) compared with controls. Associations were similar for CKD of unknown origin. Patients with hypertensive/renovascular nephropathy had impaired global longitudinal and area strain, and higher E/e' ratio. Patients with glomerulonephritis/vasculitis had higher LV mass index, while patients with PKD had better global longitudinal strain than controls. All findings remained significant in adjusted analysis, except for the impaired global longitudinal strain in hypertensive/renovascular nephropathy.

CONCLUSION

Glomerulonephritis/vasculitis, hypertensive/renovascular nephropathy, CKD of unknown origin, and diabetic nephropathy/renovascular KD in diabetes mellitus were increasingly associated with adverse cardiac findings, while PKD and tubulointerstitial nephritis were not. Aetiology might play a role regarding the cardiac manifestations of CKD.

Macrophage polarization and signaling in diabetic kidney disease: a catalyst for disease progression

Diabetic kidney disease (DKD) is a serious complication of diabetes affecting millions of people worldwide. Macrophages, a critical immune cell type, are central players in the development and progression of DKD. In this comprehensive review, we delve into the intricate role of macrophages in DKD, examining how they can become polarized into proinflammatory M1 or anti-inflammatory M2 phenotypes. We explore the signaling pathways involved in macrophage recruitment and polarization in the kidneys, including the key cytokines and transcription factors that promote M1 and M2 polarization. In addition, we discuss the latest clinical studies investigating macrophages in DKD and explore the potential of hypoglycemic drugs for modulating macrophage polarization. By gaining a deeper understanding of the mechanisms that regulate macrophage polarization in DKD, we may identify novel therapeutic targets for this debilitating complication of diabetes. This review provides valuable insights into the complex interplay between macrophages and DKD, shedding light on the latest developments in this important area of research. This review aims to enhance understanding of the role that macrophages play in the pathogenesis of DKD.

Hepatocyte growth factor attenuates high glucose-disturbed mitochondrial dynamics in podocytes by decreasing ARF6-dependent DRP1 translocation

Diabetic nephropathy (DN), one of the most common complications of Diabetes Mellitus, is the leading cause of end-stage renal diseases worldwide. Our previous study proved that hepatocyte growth factor (HGF) alleviated renal damages in mice with type 1 Diabetes Mellitus by suppressing overproduction of reactive oxygen species (ROS) in podocytes, while the further mechanism of how HGF lessens ROS production had not been clarified yet. ADP-ribosylation factor 6 (ARF6), the member of the small GTPases superfamilies, is widely spread among epithelial cells and can be activated by the HGF/c-Met signaling. Thus, this study was aimed to explore whether HGF could function on mitochondrial homeostasis, the main resource of ROS, in podocytes exposed to diabetic conditions via ARF6 activation. Our in vivo data showed that HGF markedly ameliorated the pathological damages in kidneys of db/db mice, especially the sharp decline of podocyte number, which was mostly blocked by the ARF6 inhibitor SecinH3. Correspondingly, our in vitro data revealed that HGF protected against high glucose-induced podocyte injuries by increasing ARF6 activity. Besides, this ARF6-dependent beneficial effect of HGF on podocytes was accompanied by improved mitochondrial dynamics and declined DRP1 translocation from cytosol to mitochondria. Collectively, our findings confirm the ability of HGF maintaining mitochondrial homeostasis in diabetic podocytes via decreasing ARF6-dependent DRP1 translocation and shed light on the novel mechanism of HGF treatment for DN.

The Role of Autophagy in Type 2 Diabetic Kidney Disease Management

Diabetic kidney disease (DKD), or diabetic nephropathy (DN), is one of the most prevalent complications of type 2 diabetes mellitus (T2DM) and causes severe burden on the general welfare of T2DM patients around the world. While several new agents have shown promise in treating this condition and potentially halting the progression of the disease, more work is needed to understand the complex regulatory network involved in the disorder. Recent studies have provided new insights into the connection between autophagy, a physiological metabolic process known to maintain cellular homeostasis, and the pathophysiological pathways of DKD. Typically, autophagic activity plays a role in DKD progression mainly by promoting an inflammatory response to tissue damage, while both overactivated and downregulated autophagy worsen disease outcomes in different stages of DKD. This correlation demonstrates the potential of autophagy as a novel therapeutic target for the disease, and also highlights new possibilities for utilizing already available DN-related medications. In this review, we summarize findings on the relationship between autophagy and DKD, and the impact of these results on clinical management strategies.

Identification and validation of disulfidptosis-related gene signatures and their subtype in diabetic nephropathy

Background: Diabetic nephropathy (DN) is the most common complication of diabetes, and its pathogenesis is complex involving a variety of programmed cell death, inflammatory responses, and autophagy mechanisms. Disulfidptosis is a newly discovered mechanism of cell death. There are little studies about the role of disulfidptosis on DN. Methods: First, we obtained the data required for this study from the GeneCards database, the Nephroseq v5 database, and the GEO database. Through differential analysis, we obtained differential disulfidptosis-related genes. At the same time, through WGCNA analysis, we obtained key module genes in DN patients. The obtained intersecting genes were further screened by Lasso as well as SVM-RFE. By intersecting the results of the two, we ended up with a key gene for diabetic nephropathy. The diagnostic performance and expression of key genes were verified by the GSE30528, GSE30529, GSE96804, and Nephroseq v5 datasets. Using clinical information from the Nephroseq v5 database, we investigated the correlation between the expression of key genes and estimated glomerular filtration rate (eGFR) and serum creatinine content. Next, we constructed a nomogram and analyzed the immune microenvironment of patients with DN. The identification of subtypes facilitates individualized treatment of patients with DN. Results: We obtained 91 differential disulfidptosis-related genes. Through WGCNA analysis, we obtained 39 key module genes in DN patients. Taking the intersection of the two, we preliminarily screened 20 genes characteristic of DN. Through correlation analysis, we found that these 20 genes are positively correlated with each other. Further screening by Lasso and SVM-RFE algorithms and intersecting the results of the two, we identified CXCL6, CD48, C1QB, and COL6A3 as key genes in DN. Clinical correlation analysis found that the expression levels of key genes were closely related to eGFR. Immune cell infiltration is higher in samples from patients with DN than in normal samples. Conclusion: We identified and validated 4 DN key genes from disulfidptosis-related genes that CXCL6, CD48, C1QB, and COL6A3 may be key genes that promote the onset of DN and are closely related to the eGFR and immune cell infiltrated in the kidney tissue.

A Review of the Potential of Nuclear Factor [Erythroid-Derived 2]-like 2 Activation in Autoimmune Diseases

An autoimmune disease is the consequence of the immune system attacking healthy cells, tissues, and organs by mistake instead of protecting them. Inflammation and oxidative stress (OS) are well-recognized processes occurring in association with acute or chronic impairment of cell homeostasis. The transcription factor Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is of major importance as the defense instrument against OS and alters anti-inflammatory activities related to different pathological states. Researchers have described Nrf2 as a significant regulator of innate immunity. Growing indications suggest that the Nrf2 signaling pathway is deregulated in numerous diseases, including autoimmune disorders. The advantageous outcome of the pharmacological activation of Nrf2 is an essential part of Nrf2-based chemoprevention and intervention in other chronic illnesses, such as neurodegeneration, cardiovascular disease, autoimmune diseases, and chronic kidney and liver disease. Nevertheless, a growing number of investigations have indicated that Nrf2 is already elevated in specific cancer and disease steps, suggesting that the pharmacological agents developed to mitigate the potentially destructive or transformative results associated with the protracted activation of Nrf2 should also be evaluated. The activators of Nrf2 have revealed an improvement in the progress of OS-associated diseases, resulting in immunoregulatory and anti-inflammatory activities; by contrast, the depletion of Nrf2 worsens disease progression. These data strengthen the growing attention to the biological properties of Nrf2 and its possible healing power on diseases. The evidence supporting a correlation between Nrf2 signaling and the most common autoimmune diseases is reviewed here. We focus on the aspects related to the possible effect of Nrf2 activation in ameliorating pathologic conditions based on the role of this regulator of antioxidant genes in the control of inflammation and OS, which are processes related to the progression of autoimmune diseases. Finally, the possibility of Nrf2 activation as a new drug development strategy to target pathogenesis is proposed.

Role of Semaphorin 3A in Kidney Development and Diseases

Kidney diseases are worldwide public health problems affecting millions of people. However, there are still limited therapeutic options against kidney diseases. Semaphorin 3A (SEMA3A) is a secreted and membrane-associated protein, which regulates diverse functions, including immune regulation, cell survival, migration and angiogenesis, thus involving in the several pathogeneses of diseases, including eyes and neurons, as well as kidneys. SEMA3A is expressed in podocytes and tubular cells in the normal adult kidney, and recent evidence has revealed that excess SEMA3A expression and the subsequent signaling pathway aggravate kidney injury in a variety of kidney diseases, including nephrotic syndrome, diabetic nephropathy, acute kidney injury, and chronic kidney disease. In addition, several reports have demonstrated that the inhibition of SEMA3A ameliorated kidney injury via a reduction in cell apoptosis, fibrosis and inflammation; thus, SEMA3A may be a potential therapeutic target for kidney diseases. In this review article, we summarized the current knowledge regarding the role of SEMA3A in kidney pathophysiology and their potential use in kidney diseases.

Diabetic complications and prospective immunotherapy

The incidence of Diabetes Mellitus is increasing globally. Individuals who have been burdened with diabetes for many years often develop complications as a result of hyperglycemia. More and more research is being conducted highlighting inflammation as an important factor in disease progression. In all kinds of diabetes, hyperglycemia leads to activation of alternative glucose metabolic pathways, resulting in problematic by-products including reactive oxygen species and advanced glycation end products. This review takes a look into the pathogenesis of three specific diabetic complications; retinopathy, nephropathy and neuropathy as well as their current treatment options. By considering recent research papers investigating the effects of immunotherapy on relevant conditions in animal models, multiple strategies are suggested for future treatment and prevention of diabetic complications with an emphasis on molecular targets associated with the inflammation.

Diabetic Kidney Disease: An Update

Diabetes is a major public health challenge and diabetic kidney disease (DKD), a broader diagnostic term than diabetic nephropathy, is the leading cause of chronic kidney disease and end-stage kidney disease in the United States and worldwide. A better understanding of the underlying pathophysiological mechanisms of DKD, and recent clinical trials testing new therapeutic interventions, have shown promising results to curb this epidemic. Given the global health burden of DKD, it is extremely important to prioritize prevention, early recognition, referral, and aggressive management of DKD in the primary care setting.

Could Systemic Inflammatory Index Predict Diabetic Kidney Injury in Type 2 Diabetes Mellitus?

BACKGROUND

The systemic inflammatory index (SII) is a new inflammatory marker that has been the subject of various studies in diseases with chronic inflammation. Diabetic nephropathy is a disease associated with chronic inflammation. We aimed to evaluate the relationship between SII and diabetic nephropathy.

METHODS

Patients with diabetes who applied to our outpatient clinic were included in the study. Diabetic patients were divided into two groups: those with diabetic nephropathy and those without. In addition, healthy individuals who applied to our clinic for general check-ups during these dates were included as the control group. The SII values and other characteristics of the three study groups were compared.

RESULTS

The median SII value for those with DKI was 584 (178-4819); for those without DKI, it was 282 (64-618); and for the control group, it was 236 (77.5-617) (p < 0.001). SII was significantly and positively correlated with BMI, weight, blood glucose, HbA1c, CRP, and creatinine, and negatively correlated with the glomerular filtration rate (GFR) value. SII values higher than 336 have 75% sensitivity and 70% specificity in detecting DKI.

CONCLUSION

The SII value can predict diabetic kidney injury in diabetics, and it can be used as an adjunctive diagnostic tool.

Relationship between Diabetic Nephropathy and Development of Diabetic Macular Edema in Addition to Diabetic Retinopathy

This study aimed to examine the relationship between diabetic retinopathy (DR) and systemic factors. We evaluated 261 patients (143 men, 118 women, aged 70.1 ± 10.1 years) with type 2 diabetes. All participants underwent a fundus examination, fundus photography using spectral domain optical coherence tomography (SD-OCT), and blood tests. For glycated hemoglobin (HbA1c) levels, the average and highest values in the past were used. We observed DR in 127 (70 men and 57 women) of 261 patients. Logistic regression analyses revealed a significant correlation between DR development and the duration of diabetes (OR = 2.40; 95% CI: 1.50), average HbA1c level (OR = 5.57; 95% CI: 1.27, 24.4), highest HbA1c level (OR = 2.46; 95% CI: 1.12, 5.38), and grade of diabetic nephropathy (DN) (OR = 6.23; 95% CI: 2.70, 14.4). Regression analyses revealed a significant correlation between the severity of DR and duration of diabetes (t = -6.66; 95% CI: 0.21, 0.39), average HbA1c level (t = 2.59; 95% CI: 0.14, 1.02), and severity of DN (t = 6.10; 95% CI: 0.49, 0.97). Logistic regression analyses revealed a significant correlation between diabetic macular edema (DME) development and DN grade (OR = 2.22; 95% CI: 1.33, 3.69). DN grade correlates with the development of DR and DME, and decreased renal function predicts the onset of DR.

Diagnostic efficacy of cystatin-c in association with different ACE genes predicting renal insufficiency in T2DM

Diabetic nephropathy (DN) seems to be the major cause of chronic kidney disease that may finally lead to End Stage Renal Disease. So, renal function assessment in type 2 diabetes mellitus (T2DM) individuals is very important. Clearly, DN pathogenesis is multifactorial and different proteins, genes and environmental factors can contribute to the onset of the disease. We assessed sensitive and specific biomarkers (in blood and urine) which can predict kidney disease susceptibility among T2DM patients. Serum cystatin-c (cyst-c) in blood and urinary hemeoxygenase (HO-1) in addition to ACE I/D polymorphism and ACE G2350A genotypes. Hundred and eight T2DM patients and 85 controls were enrolled. Serum cystatin-c and urinary (HO-1) were tested by ELISA. Genetic determination of both ACE I/D polymorphism and ACE G2350A genotypes was performed by PCR for all participants. Significant rise in serum cystatin-c and urinary HO-1 levels were shown in diabetic groups compared with control group. Moreover, GG genotype of ACE G2350A gene in diabetic group was associated with rise in serum cystatin-c and urinary HO-1 compared with control group. Mutant AA genotype demonstrated increase in urinary HO-1. DD polymorphism was associated with rise in serum creatinine and cyst-c in diabetic group. Positive correlation was seen between duration of diabetes and serum cyst-c and between serum glucose and urinary (HO-1) in diabetic group. The results from this study indicated an association of serum cystatin-c with GG genotype of ACE G2350A in conjugation with DD polymorphism of ACE I/D which could be an early predictor of tubular injury in T2DM diabetic patients.

Autophagy and its therapeutic potential in diabetic nephropathy

Diabetic nephropathy (DN), the leading cause of end-stage renal disease, is the most significant microvascular complication of diabetes and poses a severe public health concern due to a lack of effective clinical treatments. Autophagy is a lysosomal process that degrades damaged proteins and organelles to preserve cellular homeostasis. Emerging studies have shown that disorder in autophagy results in the accumulation of damaged proteins and organelles in diabetic renal cells and promotes the development of DN. Autophagy is regulated by nutrient-sensing pathways including AMPK, mTOR, and Sirt1, and several intracellular stress signaling pathways such as oxidative stress and endoplasmic reticulum stress. An abnormal nutritional status and excess cellular stresses caused by diabetes-related metabolic disorders disturb the autophagic flux, leading to cellular dysfunction and DN. Here, we summarized the role of autophagy in DN focusing on signaling pathways to modulate autophagy and therapeutic interferences of autophagy in DN.

Influenza Vaccination Reduces the Risk of Liver Cancer in Patients with Chronic Kidney Disease: A Nationwide Population-Based Cohort Study

Previous studies have indicated that influenza vaccination reduces the development of lung cancer. However, the protective effects of influenza vaccination on primary liver cancer in patients with chronic kidney disease (CKD) are unclear. This cohort study identified 12,985 patients aged at least 55 years who had received a diagnosis of CKD between 1 January 2001 and 31 December 2012 from the National Health Insurance Research Database of Taiwan. The patients were classified according to vaccination status. Propensity score matching was used to reduce selection bias. Cox proportional hazards regression analysis was used to evaluate the correlation between influenza vaccination and primary liver cancer in patients with CKD. The prevalence of primary liver cancer was lower in patients with CKD who had received an influenza vaccine (adjusted hazard ratio: 0.45, 95% confidence interval [CI]: 0.35−0.58, p < 0.001). The protective effects were observed regardless of sex, age, and comorbidities. Moreover, dose-dependent protective effects were observed. In the subgroup analysis, where the patients were classified by the number of vaccinations received, the adjusted hazard ratios for 1, 2−3, and ≥4 vaccinations were 0.86 (95% CI: 0.63−1.17), 0.45 (95% CI: 0.31−0.63), and 0.21 (95% CI: 0.14−0.33), respectively. In conclusion, influenza vaccination was associated with a lower incidence of liver cancer in patients with CKD.

Dual specificity phosphatase 22 suppresses mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK signaling pathway in diabetic nephropathy

Dual specificity phosphatase 22 (DUSP22) regulates fibrosis and inflammation, which may be implicated in the development of diabetic nephropathy (DN). Hence, the current study aimed to assess the effect of DUSP22 on cell proliferation, apoptosis, fibrosis and inflammation in mouse mesangial cell line (SV40-MES13) under both high glucose (HG) and low glucose (LG) conditions. SV40-MES13 cells were treated with HG and LG, then HG-group cells were transfected with DUSP22 overexpression and control plasmids, meanwhile LG-group cells were transfected with DUSP22 and control siRNAs. Then, cell proliferation using Cell Counting Kit-8, cell apoptosis by TUNEL assay, protein expression using western blotting, inflammatory cytokines using ELISA and RNA using reverse transcription-quantitative PCR were determined. DUSP22 mRNA and protein were decreased in SV40-MES13 cells under the HG condition compared with those under the LG condition. Under the HG condition, DUSP22 overexpression suppressed SV40-MES13 cell proliferation at 48 and 72 h as well as Bcl2, but it facilitated TUNEL-reflected apoptotic rate and cleaved-caspase-3; besides, DUSP22 overexpression restrained proteins of fibronectin 1, collagen I, transforming growth factor beta 1, and their corresponding mRNAs. As to the inflammation, DUSP22 overexpression downregulated TNF-α, IL-1β, IL-6 and IL-12 under the HG condition. By contrast, DUSP22 siRNA promoted SV40-MES13 cell proliferation, fibrosis and inflammation, but attenuated apoptosis in SV40-MES13 cells under the LG condition. Additionally, DUSP22 overexpression inactivated phosphorylated (p)-ERK, p-JNK, and p-P38 in HG-treated SV40-MES13 cells; differently, DUSP22 small interfering RNA facilitated them under the LG condition. In conclusion, DUSP22 suppresses HG-induced mesangial cell hyperproliferation, fibrosis, inflammation and the MAPK pathway, implying its potency in DN treatment.

Renal hemodynamic dysfunction and neuropathy in longstanding type 1 diabetes: Results from the Canadian study of longevity in type 1 diabetes

AIMS

To determine the relationship between renal hemodynamic function and neuropathy in adults with ≥50-years of type 1 diabetes (T1D) compared to nondiabetic controls.

METHODS

Glomerular filtration rate (GFR, inulin), effective renal plasma flow (ERPF, p-aminohippurate), modified Toronto Clinical Neuropathy Score (mTCNS), corneal confocal microscopy, nerve conduction, and heart rate variability (autonomic function) were measured; afferent (RA) and efferent (RE) arteriolar resistances were estimated using the Gomez equations in 74 participants with T1D and in 75 controls. Diabetic kidney disease (DKD) non-resistors were defined by eGFRMDRD < 60 ml/min/1.73 m2 or 24-h urine albumin excretion >30 mg/day. Linear regression was applied to examine the relationships between renal function (dependent variable) and neuropathy measures (independent variable), adjusted for age, sex, HbA1c, systolic blood pressure, low density lipoprotein cholesterol, and 24-h urine albumin to creatinine ratio.

RESULTS

Higher mTCNS associated with lower renal blood flow (β ± SE:-9.29 ± 4.20, p = 0.03) and greater RE (β ± SE:32.97 ± 15.43, p = 0.04) in participants with T1D, but not in controls. DKD non-resistors had a higher mTCNS and worse measures of corneal nerve morphology compared to those without DKD. Renal hemodynamic parameters did not associate with autonomic nerve function.

CONCLUSIONS

Although neurological dysfunction in the presence of diabetes may contribute to impaired renal blood flow resulting in ischemic injury in patients with T1D, early autonomic dysfunction does not appear to be associated with kidney function changes.

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

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

The critical role of dysregulated autophagy in the progression of diabetic kidney disease

Diabetic kidney disease (DKD) is one of the major public health problems in society today. It is a renal complication caused by diabetes mellitus with predominantly microangiopathy and is a major cause of end-stage renal disease (ESRD). Autophagy is a metabolic pathway for the intracellular degradation of cytoplasmic products and damaged organelles and plays a vital role in maintaining homeostasis and function of the renal cells. The dysregulation of autophagy in the hyperglycaemic state of diabetes mellitus can lead to the progression of DKD, and the activation or restoration of autophagy through drugs is beneficial to the recovery of renal function. This review summarizes the physiological process of autophagy, illustrates the close link between DKD and autophagy, and discusses the effects of drugs on autophagy and the signaling pathways involved from the perspective of podocytes, renal tubular epithelial cells, and mesangial cells, in the hope that this will be useful for clinical treatment.

Current status of diabetic kidney disease and latest trends in management

Diabetic kidney disease (DKD) is one of the major microvascular complications of diabetes and is leading cause of end-stage renal disease (ESRD) and one of major risk factors of cardiovascular disease (CVD).

Fatty acid-binding protein 4 in kidney diseases: From mechanisms to clinics

Considerable evidence indicated the relationship between fatty acid-binding protein 4 (FABP4) and kidney diseases. FABP4, a small molecular lipid chaperone, is identified to regulate fatty acid oxidation, inflammation, apoptosis, endoplasmic reticulum stress and macrophage-to-myofibroblast transition in kidney diseases. Many studies have shown that circulating FABP4 level is related to proteinuria, renal function decline, cardiovascular complications of end-stage renal disease and even the prognosis of kidney transplanted patients. Notably, pharmacological or genetic inhibition of FABP4 attenuated renal injury in the various experimental models of kidney diseases, making it promising to develop potential therapeutic strategies targeting FABP4 in kidney diseases. In this study, we updated and reviewed the mechanisms and clinical significance of FABP4 in kidney diseases.

Demethylzeylasteral reduces the level of proteinuria in diabetic nephropathy: Screening of network pharmacology and verification by animal experiment

This study aimed to use network pharmacology to detail the natural components isolated from Triptergium wilfordii Hook F (TwHF) and examine the effect of the main component (demethylzeylasteral, DEM) on rat models of diabetic nephropathy (DN). In this study, we used network pharmacology to detail the natural components isolated from TwHF, referenced a gene library when screening for components effective in the management of DN, and DEM was confirmed in DN rats. All data were analyzed using the Discovery Studio 4.5 System and the systems Dock online docking method platform. All 24 rats were divided into 4 groups: control, DN, TwHF, and DEM. Blood and urine samples were tested at 0, 8, and 12 weeks. Renal histopathological changes were scored. Network pharmacology indicated that 370 compounds and 46 small molecules (including DEM) were biologically active constituents of TwHF, mainly affecting the inflammatory response through PI3K-Akt and Jak-STAT pathways. Proteinuria in the TwHF and DEM groups was significantly lower than in the DN group (p ≤ .001), and the decrease in proteinuria in the DEM group was more obvious than in the TwHF group (p = .004). The tubular interstitial scores were better in the DEM group than in the TwHF and DN groups. These results indicate that DEM effectively reduced proteinuria and alleviated the tubular interstitial changes in rat models of DN, which may be provide a scientific foundation for the development of novel drugs for treatment of DN.

Insights into the Uses of Traditional Plants for Diabetes Nephropathy: A Review

Diabetic nephropathy (DN) is a serious kidney illness characterized by proteinuria, glomerular enlargement, reduced glomerular filtration, and renal fibrosis. DN is the most common cause of end-stage kidney disease, accounting for nearly one-third of all cases of diabetes worldwide. Hyperglycemia is a major factor in the onset and progression of diabetic nephropathy. Many contemporary medicines are derived from plants since they have therapeutic properties and are relatively free of adverse effects. Glycosides, alkaloids, terpenoids, and flavonoids are among the few chemical compounds found in plants that are utilized to treat diabetic nephropathy. The purpose of this review was to consolidate information on the clinical and pharmacological evidence supporting the use of a variety of medicinal plants to treat diabetic nephropathy.

Curcumin Blocks High Glucose-Induced Podocyte Injury via RIPK3-Dependent Pathway

Podocyte loss is well known to play a critical role in the early progression of diabetic nephropathy. A growing number of studies are paying attention to necroptosis, a programmed form of cell necrosis as a mechanism of podocyte loss. Although necroptosis is a recently established concept, the significance of receptor interacting serine/threonine kinase 3 (RIPK3), a gene that encodes for the homonymous enzyme RIPK3 responsible for the progression of necroptosis, is well studied. Curcumin, a natural hydrophobic polyphenol compound responsible for the yellow color of Curcuma longa, has drawn attention due to its antioxidant and anti-inflammatory effects on cells prone to necroptosis. Nonetheless, effects of curcumin on high glucose-induced podocyte necroptosis have not been reported yet. Therefore, this study investigated RIPK3 expression in high glucose-treated podocytes to identify the involvement of necroptosis via the RIPK3 pathway and the effects of curcumin treatment on RIPK3-dependent podocytopathy in a hyperglycemic environment. The study discovered that increased reactive oxygen species (ROS) in renal podocytes induced by high glucose was improved after curcumin treatment. Curcumin treatment also significantly restored the upregulated levels of VEGF, TGF-β, and CCL2 mRNAs and the downregulated level of nephrin mRNA in cultured podocytes exposed to a high glucose environment. High glucose-induced changes in protein expression of TGF-β, nephrin, and CCL2 were considerably reverted to their original levels after curcumin treatment. Increased expression of RIPK3 in high glucose-stimulated podocytes was alleviated by curcumin treatment as well as N-acetyl cysteine (NAC, an antioxidant) or GSK′872 (a RIPK3 inhibitor). Consistent with this, the increased necroptosis-associated molecules, such as RIPK3, pRIPK3, and pMLKL, were also restored by curcumin in high glucose-treated mesangial cells. DCF-DA assay confirmed that such a result was attributed to the reduction of RIPK3 through the antioxidant effect of curcumin. Further observations of DCF-DA-sensitive intracellular ROS in NAC-treated and GSK′872-treated podocyte groups showed a reciprocal regulatory relationship between ROS and RIPK3. The treatment of curcumin and GSK′872 in podocytes incubated with high glucose protected from excessive intracellular superoxide anion production. Taken together, these results indicate that curcumin treatment can protect against high glucose-induced podocyte injuries by suppressing the abnormal expression of ROS and RIPK3. Thus, curcumin might be a potential therapeutic agent for diabetic nephropathy as an inhibitor of RIPK3.

The effect of renin-angiotensin-aldosterone system inhibitors on continuous and binary kidney outcomes in subgroups of patients with diabetes: a meta-analysis of randomized clinical trials

INTRODUCTION

Diabetic nephropathy is the leading cause of kidney failure. Clinical practice guidelines recommend prescribing renin-angiotensin aldosterone system inhibitors (RAASi) to prevent diabetic nephropathy at any stage. We conducted this systematic review and meta-analysis to compare the effects of RAASi with placebo and other antihypertensive agents in adults with diabetes on continuous and binary kidney outcomes to provide a comprehensive review of the class effect of RAASi on several subgroups.

METHODS

A systematic electronic search to identify randomized clinical trials of a duration of ≥ 12 months that recruited ≥ 50 adult participants with type 1 or 2 diabetes with any stage of chronic kidney disease and proteinuria was conducted in MEDLINE, CINAHL, EMBASE, and Cochrane library with no language restriction. Studies were screened against the inclusion and exclusion criteria by two reviewers independently.

RESULTS

In this meta-analysis, evidence was drawn from 26,551 patients with diabetes from 46 studies. Our analysis shows that RAASi were better than placebo in reducing SrCr (the raw mean difference [RMD] = -13.4 μmol/L; 95%CI: -16.78; -10.01) and albuminuria levels (standardized mean difference [SMD] = -1; 95%CI: -1.57, -0.44, I2 = 96%). When compared to other active treatments, RAASi did not reduce SrCr (RMD = 0.03 μmol/L; 95%CI: -6.4, 6.10, I2 = 76%), caused a non-significant reduction of GFR levels (RMD = -1.21 mL/min; 95%CI: -4.52, 2.09, I2 = 86%), and resulted in modest reduction of albuminuria levels (SMD = -0.55; 95%CI: -0.95, -0.16, I2 = 90%). RAASi were superior to placebo in reducing the risks of kidney failure (OR = 0.74; 95%CI: 0.56, 0.97) and doubling of serum creatinine levels (SrCr; OR = 0.71; 95%CI: 0.55, 0.91), but not in promoting the regression of albuminuria (OR = 3.00; 95%CI: 0.96, 9.37). RAASi, however, were not superior to other antihypertensives in reducing the risks of these outcomes. Patients with type 2 diabetes, macroalbuminuria and longer duration of diabetes had less risk of developing kidney failure in placebo-controlled trials, while longer duration of diabetes, normal kidney function, and hypertension increased the probability of achieving regression of albuminuria in active-controlled trials.

CONCLUSION

While our findings revealed the non-superiority of RAASi over other antihypertensives and portrayed a class effect on several subgroups of study participants, it raised a challenging question on whether RAASi deserve their place as first-line therapy in managing diabetic nephropathy.

Prevalence of type 2 diabetes mellitus, impaired fasting glucose, general obesity, and abdominal obesity in patients with bipolar disorder: A systematic review and meta-analysis

OBJECTIVES

The study herein aimed to assess the prevalence of type 2 diabetes mellitus (T2DM), impaired fasting glucose (IFG), as well as general and abdominal obesity in patients with bipolar disorder (BD). We also compared the prevalence of T2DM and general obesity in patients with BD with age- and gender-matched healthy controls.

METHODS

A systematic search of Embase, Medline, PubMed, and APA PsycArticles was conducted from inception to June 2021 without language restrictions. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS) modified for case-control studies.

RESULTS

A total of forty-nine studies were included in this analysis. The pooled prevalence of T2DM was 9.6% (95% CI, 7.3-12.2%). Patients with BD had a nearly 1.6 times greater risk of developing T2DM compared to their age- and gender-matched controls (RR=1.57, 95% CI 1.36-1.81, p<0.001). In the present analysis, IFG is defined as a fasting plasma glucose (FPG) ≥ 100 mg/dL (FPG≥100) with a prevalence of 22.4% (95% CI, 16.7-28.7%), or as an FPG equal to or greater than 110 mg/d (FPG≥110) with a prevalence of 14.8% (95% CI, 10.8-19.3%). The prevalence of general obesity (BMI≥30 kg/m²) was 29.0% (95% CI, 22.8-35.6%); the risk of obesity was almost twice the rate reported in patients with BD compared to controls (RR=1.67, 95% CI 1.32-2.12, p<0.001). We also observed that more than half of the BD participants had abdominal obesity (i.e., prevalence of 51.1%; 95% CI, 45.0-57.3%).

LIMITATIONS

A significant degree of heterogeneity was detected. Sources of heterogeneity included differences in study designs, inclusion criteria, measurement tools, and data analysis methods.

CONCLUSION

Bipolar disorder is associated with a higher prevalence of T2DM, IFG, general obesity, and abdominal obesity. Type 2 diabetes mellitus and obesity are significantly more prevalent in patients with BD than in their age- and gender-matched controls.

STUDY REGISTRATION

CRD42021258431.

Association of significantly elevated plasma levels of NGAL and IGFBP4 in patients with diabetic nephropathy

Background

Diabetic nephropathy (DN) is a type of progressive kidney disease affecting approximately 40% of patients with diabetes. Current DN diagnostic criteria predominantly rely on albuminuria and serum creatinine (sCr) levels. However, the specificity and reliability of both markers are limited. Hence, reliable biomarkers are required for early diagnosis to effectively manage DN progression.

Methods

In this study, a cohort of 159 individuals were clinically evaluated and the plasma levels of NGAL, IGFBP-1, IGFBP-3, and IGFBP-4 were determined using Multiplexing Assays. Additionally, the association between the plasma levels of NGAL, IGFBP-1, IGFBP-3, and IGFBP-4 in patients with DN were compared to those in patients with T2D without kidney disease and control participants.

Results

Circulating level of NGAL were significantly higher in people with DN compared to people with T2D and non-diabetic groups (92.76 ± 7.5, 57.22 ± 8.7, and 52.47 ± 2.9 mg/L, respectively; p <  0.0001). IGFBP-4 showed a similar pattern, where it was highest in people with DN (795.61 ng/ml ±130.7) compared to T2D and non-diabetic people (374.56 ng/ml ±86.8, 273.06 ng/ml ±27.8 respectively, ANOVA p <  0.01). The data from this study shows a significant positive correlation between NGAL and IGFBP-4 in people with DN (ρ = .620, p <  0.005). IGFBP-4 also correlated positively with creatinine level and negatively with eGFR, in people with DN supporting its involvement in DN.

Conclusion

The data from this study shows a parallel increase in the plasma levels of NGAL and IGFBP-4 in DN. This highlights the potential to use these markers for early diagnosis of DN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02692-z.

Possible pathway for heart failure with preserved ejection fraction prevention and treatment: the angiotensin-converting enzyme inhibitor effect on endothelial function in comorbid patients

Aim      To evaluate the effect of perindopril on the endothelial function and levels of endothelial dysfunction markers in groups of patients with heart failure with preserved (HFpEF) and mid-range (intermediate) left ventricular ejection fraction (HFmrEF).Material and methods  40 patients with HFpEF (n=20) and HFmrEF (n=20) were evaluated. At baseline, parameters of the morpho-functional state of large blood vessels and of microvessels were evaluated with photoplethysmography, and levels of E-selectin and endothelin-1 (ET-1) were measured. The patients were prescribed perindopril, and after 12 months of treatment, photoplethysmographic parameters and endothelial dysfunction markers were determined again.Results After 12 months of the perindopril treatment, improvements in the endothelial function of both large blood vessels and microvessels were noted. The phase shift increased from 10.1 to 10.9 ms in the HFpEF group (р=0.001) and from 8.35 to 9.65 ms in the HFmrEF group (р=0.002). Furthermore, the occlusion index increased from 1.45 to 1.75 in patients with HFpEF (р=0.004) and from 1.5 to 1.75 in patients with HFmrEF (р=0.010). The Е-selectin concentration decreased in both groups, from 57.25 to 42.4 ng/ml (р=0.00008) and from 40.5 to 35.7 ng/ml (р=0.010) in patients with HFpEF and HFmrEF, respectively. The ET-1 concentration decreased from pg/ml (р=0.010) in patients with HFpEF whereas in patients with HFmrEF, there was no significant change in the ET-1 concentration after 12 months of the perindopril treatment.Conclusion      At 12 months, the endothelial function improved and E-selectin and ET-1 levels decreased in patients with HFpEF and HFmrEF.

Targeting mTOR Signaling in Type 2 Diabetes Mellitus and Diabetes Complications

The mechanistic target of rapamycin (mTOR) is a pivotal regulator of cell metabolism and growth. In the form of two different multi-protein complexes, mTORC1 and mTORC2, mTOR integrates cellular energy, nutrient and hormonal signals to regulate cellular metabolic homeostasis. In type 2 diabetes mellitus (T2DM) aberrant mTOR signaling underlies its pathological conditions and end-organ complications. Substantial evidence suggests that two mTOR-mediated signaling schemes, mTORC1-p70S6 kinase 1 (S6K1) and mTORC2-protein kinase B (AKT), play a critical role in insulin sensitivity and that their dysfunction contributes to development of T2DM. This review summaries our current understanding of the role of mTOR signaling in T2DM and its associated complications, as well as the potential use of mTOR inhibitors in treatment of T2DM.

Treatment with crocin suppresses diabetic nephropathy progression via modulating TGF-β1 and oxidative stress in an experimental model of pinealectomized diabetic rats

One of the most common complications of diabetes is diabetic nephropathy (DN). Uncontrolled hyperglycemia leads to histopathologic alterations in the kidney that prevent normal renal function. This study aimed to explore the effects of crocin treatment via virtue of its numerous beneficial properties in streptozotocin-induced pinealectomized diabetic rats. The pinealectomy procedure was conducted on the first day of the study. On the 30th day following pinealectomy, streptozotocin (STZ) (50 mg/kg) was administered intraperitoneally in Wistar rats for induction of diabetes. Diabetes was confirmed on the 3rd day following STZ administration by determining the glucose levels. Daily crocin treatment intraperitoneally for 15 days (50 mg/kg) ameliorated impaired renal oxidant/antioxidant balance, reduced TGF-β1 immuno-staining around tubules, and promoted improvement of renal architecture. Moreover, crocin administration improved altered renal function parameters, including serum Cr and BUN, and also increased creatinine clearance. In conclusion, the protective effects of crocin on diabetic nephropathy might be associated with its powerful antioxidant properties, its ability to improve tissue antioxidant status, and its ability to prevent inflammatory pathways.

Phosphodiesterase 4 inhibitors in diabetic nephropathy

Phosphodiesterase subtype 4 (PDE4) hydrolyzes cyclic AMP, a secondary messenger that mediates intracellular signaling, and plays key roles in inflammatory and fibrotic responses. Based on these significant anti-inflammatory effects, oral administration of PDE4 inhibitor is approved for the treatment of chronic obstructive pulmonary disease, atopic dermatitis, and psoriasis. However, PDE4 inhibition also has adverse effects, such as diarrhea, vomiting, dyspepsia, and headache. Therefore, the application of PDE4 inhibitors for chronic diseases, such as diabetes and its complications, has not yet been approved. Recent studies have reported the clinical benefits of pentoxifylline, a non-selective PDE inhibitor, in patients with kidney disease. The PDE4 inhibitor, roflumilast, also clearly ameliorates the symptoms of diabetes mellitus by improving hyperglycemia and insulin resistance. However, the beneficial effects of PDE4 inhibition on diabetic nephropathy have not yet been evaluated, and its potential mechanisms of action remain unknown. In this review, we discuss the beneficial effects of PDE4 inhibitors and their mechanisms of action using diabetes and DN models.

LncRNA NNT-AS1 regulates proliferation, ECM accumulation and inflammation of human mesangial cells induced by high glucose through miR-214-5p/smad4

Background

LncRNA NNT-AS1 (NNT-AS1) has been extensively studied as the causative agent in propagation and progression of lung and bladder cancers, and cholangiocarcinoma. However, its significance in proliferation and inflammation of diabetic nephropathy is enigmatic. This study focuses on the molecular mechanisms followed by NNT-AS1 to establish diabetic nephropathy (DN) and its potential miRNA target.

Methods

Bioinformatics analysis to identify potential miRNA target of NNT-AS1 and smad4 transcription factor was conducted using LncBase and TargetScan, and was subsequently confirmed by luciferase reporter assay. Relative quantitative expression of NNT-AS1 in human glomerular mesangial cells (HGMCs) was detected through quantitative real-time PCR and WB analysis. Cell proliferation was detected through CCK-8 assay, whereas, ELISA was conducted to evaluate the expression of inflammatory cytokines. Following this, relative expression of miR-214-5p and smad4 were confirmed through qRT-PCR and western blot analysis.

Results

Results from the experiments manifested up-regulated levels of NNT-AS1 and smad4 in the blood samples of DN patients as well as in HGMCs, whereas, downregulated levels of miR-214-5p were measured in the HGMCs suggesting the negative correlation between NNT-AS1 and miR-214-5p. Potential binding sites of NNT-AS1 showed miR-214-5p as its direct target and NNT-AS1 as potential absorber for this microRNA, in turn increasing the expression of transcription factor smad4.

Conclusion

The data suggests that NNT-AS1 can be positively used as a potential biomarker and indicator of DN and causes extracellular matrix (ECM) accumulation and inflammation of human mesangial cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02580-y.

1. Up-regulated levels of NNT-AS1 and smad4 in DN samples and HGMCs was manifested.

2. Potential binding sites of NNT-AS1 showed miR-214-5p as its direct target and NNT-AS1 as potential absorber for this microRNA, in turn increasing the expression of transcription factor smad4.

3. The results manifested that knocking-down NNT-AS1 can significantly decrease the inflammation and progression of DN and hence can be used as a potential therapeutic target.

Sitagliptin's renoprotective effect in a diabetic nephropathy model in rats: The potential role of PI3K/AKT pathway

Management of diabetic nephropathy (DN) is far from satisfactory. There is a rising role of the involvement of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in the pathogenesis of DN. This study aimed at investigating the renoprotective effects of PI3K/AKT pathway via sitagliptin in a rat model of DN. Thirty-two male Wistar rats were divided into four groups (eight rats each): (I) control, (II) sitagliptin, (III) DN, and (IV) DN + sitagliptin. Fasting blood glucose (FBG), kidney index, and kidney function tests in both blood and urine were measured. The levels of superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta (TGF-β) and gene expressions of PI3K, pPI3K, AKT, and pAKT in renal tissue were detected. Renal histopathological and immunohistochemical studies were evaluated. DN + sitagliptin group showed significant decrease in FBG and kidney index, improvement in kidney function tests, and a decrease in levels of TNF-α and TGF-β in renal tissues compared with DN group. This was associated with significant increase in SOD and gene expressions of PI3K and AKT and their phosphorylated active forms in renal tissue in DN + sitagliptin group compared with DN group. Moreover, DN + sitagliptin group showed apparent decrease in amount of collagen fibers and expression of alpha-smooth muscle actin (α-SMA) compared with DN group. This work shows that sitagliptin improved renal functions and histopathological changes, impeded inflammation, and oxidative stress and upregulated PI3K/AKT pathway which highlights its renoprotective effects in a rat model of DN.

Dapagliflozin Reduces Urinary Albumin Excretion by Downregulating the Expression of cAMP, MAPK, and cGMP-PKG Signaling Pathways Associated Genes

Objective: Diabetic nephropathy (DN), the most severe complication of diabetes mellitus, is characterized by albuminuria and progressive loss of kidney function. Dapagliflozin (DAP), a sodium-glucose cotransporter inhibitor, is an oral medication that improves blood glucose control in diabetic patients. However, the effects and mechanisms of DAP on DN remain unclear. Materials and Methods: The effect of DAP was based on a retrospective cohort study of patients who underwent 2-year surveillance, and the concentration of urine albumin-to-creatinine ratio, glomerular filtration rate, and serum creatinine were collected after treatment with DAP. To investigate the underlying mechanisms through which DAP reduces urinary albumin excretion, we used RNA-sequencing (RNA-seq) to analyze gene expression in human kidney 2 (HK-2) cells treated with DAP. Results: The retrospective cohort analysis indicated that DAP could reduce the excretion rate of urinary albumin in patients with type 2 diabetes and renal impairment. The results of the RNA-seq experiments showed 349 differentially expressed genes between DAP-treated HK-2 cells and control cells. Gene ontology annotation enrichment analysis showed that DAP mainly affected the expression of integral component of membrane- and cell junction-related genes, while the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that DAP primarily downregulated the expression of gene clusters associated with cyclic adenosine monophosphate, mitogen-activated protein kinase, and cyclic guanosine monophosphate-protein kinase G signaling pathways, which play critical roles in the progression of DN. Conclusion: Our results shed light on the mechanism by which DAP controls DN progression and provide a theoretical basis for the clinical treatment of DN.

Frequency and factors associated with proteinuria in COVID-19 patients: a cross-sectional study

Proteinuria is a marker of severity and poor outcome of patients in intensive care unit (ICU). The objective of this study was to determine the frequency of proteinuria and the risk factors associated with proteinuria in Congolese COVID-19 patients. The present cross sectional study of proteinuria status is a post hoc analysis of data from 80 COVID-19 patients admitted at Kinshasa Medical Center (KMC) from March 10th to July 10th, 2020. The population under study came from all adult inpatients (≥18 years old) with a laboratory diagnosis by polymerase chain reaction (PCR) of COVID-19 were selected and divided into two groups (positive proteinuria and negative proteinuria group). Logistic regression models helped to identify the factors associated with proteinuria. The P value significance level was 0.05. Among 80 patients who tested positive for SARS-CoV-2 RT-PCR, 55% had proteinuria. The mean age was 55.2 ± 12.8 years. Fourty-seven patients (58.8%) had history of hypertension and 26 patients (32.5%) diabetes. Multivariable analysis showed age ≥ 65 years (aOR 5,04; 95% CI: 1.51-16.78), diabetes (aOR 3,15; 95% CI: 1.14-8.72), ASAT >40 UI/L (aOR 7,08; 95% CI: 2.40-20.87), ferritin >300 (aOR 13,47; 95% CI: 1.56-26.25) as factors independently associated with proteinuria in COVID-19 patients. Proteinuria is common in Congolese COVID-19 patients and is associated with age, diabetes, ferritin and aspartate aminotransferase (ASAT).

The effect of Cinnamomum cassia extract on oxidative stress in the liver and kidney of STZ-induced diabetic rats

OBJECTIVES

Many diabetes-related complications are caused by oxidative stress. In the current study, the protective effect of Cinnamomum cassia against diabetes-induced liver and kidney oxidative stress was evaluated.

METHODS

The male Wistar rats (n=48) were randomly divided into six groups including; control group received 500 µL normal saline orally for 42 days. Diabetes groups received intraperitoneally (i.p.) streptozotocin (STZ) as single-dose (60 mg/kg, i.p.). Cinnamon extract (100, 200, 400 mg/kg) and metformin (300 mg/kg) were orally administered to diabetic rats for 42 days. After the experiment period, the animals were anesthetized and the liver and kidney tissues were quickly removed and restored for oxidative stress evaluation. The levels of malondialdehyde (MDA), total thiol content, glutathione (GSH), nitric oxide (NO) metabolites, as well as, superoxide dismutase (SOD) and catalase (CAT) activities were measured in kidney and liver tissue.

RESULTS

The level of MDA, SOD, and CAT activities increased significantly, while the total thiol content, and NO production were significantly reduced in diabetic animals compared to the control group (from p<0.05 to p<0.001). Treatment with cinnamon extract significantly decreased the MDA level, as well as, SOD and CAT activities in the liver and kidney of diabetic rats (from p<0.05 to p<0.001). In the liver and kidney of cinnamon treated groups, GSH and total thiol contents and NO production were significantly higher than diabetic group (from p<0.05 to p<0.001).

CONCLUSIONS

Cinnamon extract due to its potent antioxidant property could be effective in decrease of diabetes-induced oxidative stress that plays a major role in renal and hepatic complications.

Blocking angiotensin 2 receptor attenuates diabetic nephropathy via mitigating ANGPTL2/TL4/NF-κB expression

BACKGROUND

Diabetic nephropathy (DN) is a consequence of diabetes mellitus (DM) and is associated with early changes in renal angiotensin II (ANG II). These changes were evaluated using ANG II blocker valsartan early from week two of diabetes (experiment I, renoprotective) and late from week nine of diabetes (experiment II, renotherapeutic) to the end of both experiments at week twelve.

METHODS AND RESULTS

In both experiments, adult male Wister rats were divided into (i) vehicle group; (ii) valsartan received oral 30 mg/Kg/day; (iii) diabetic received single 50 mg/Kg intraperitoneal streptozotocin injection; (iv) renoprotection, diabetic rats received valsartan treated in experiments I and II. DM effects on urine albumin excretion, blood pressure, and renal ANG II were measured. Urinary nephrin, kidney injury molecule-1 (KIM-1), renal angiopoietin-like protein 2 (ANGPTL2), and toll-like receptor 4 (TLR 4) mRNA expression were tested. DM-initiated fibrotic markers integrin, α-smooth muscle actin expression, and collagen IV and apoptotic protein caspase 3 were tested. DM induced early changes starting from week four in the tested variables. At week twelve, in both experiments, valsartan intervention showed a significant reduction in ANG II, ANGPTL2, TLR 4 and integrin expression and improvement in albuminuria, blood pressure, urinary biomarkers, fibrotic and apoptotic markers.

CONCLUSIONS

Changes leading to DN starts early in the disease course and ANG II reduction decreased the expression of ANGPTL2 and integrin which preserve the glomerular barrier. Blocking ANG II was able to decrease TLR 4 and inflammatory cytokines leading to decreasing DN.

VX-765 ameliorates inflammation and extracellular matrix accumulation by inhibiting the NOX1/ROS/NF-κB pathway in diabetic nephropathy

OBJECTIVE

This study explores the potential role of a highly selective caspase-1 inhibitor, VX-765, on extracellular matrix (ECM) accumulation and inflammation in diabetic nephropathy (DN) and the underlying mechanisms.

METHODS

DN rats, induced via high-fat diet/streptozotocin, were used to assess the effects of VX-765. Parallel experiments were carried out on rat mesangial cell line HBZY-1 exposed to high glucose (HG) to reveal the molecular mechanism of VX-765 in preventing DN. Survival analysis, biochemical parameters and renal oxidative stress of rats were observed, and Western blotting and immunofluorescence were evaluated. In vitro, Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOX)1 silencing by RNA interference and quantitative real-time PCR (qPCR) assays were conducted in HBZY-1 cells exposed to HG levels.

KEY FINDINGS

In vivo, VX-765 significantly reduced the increase in urine albumin excretion and ECM accumulation. The phosphorylation of nuclear factor kappa-B (NF-κB) and the expression of pro-inflammatory cytokines IL-1β, IL-6 and tumor necrosis factor (TNF)-α were significantly down-regulated. Furthermore, the generation of reactive oxygen species (ROS), phosphorylation of NF-κB and the expression of the NOX1 gene or protein were significantly decreased in HBZY-1 with VX-765 (5 μM) treatment in vitro.

CONCLUSIONS

Our results demonstrated that VX-765 exerts favourable effects on DN via the simultaneous alleviation of systemic metabolic syndrome and down-regulating the renal NOX1/ROS/NF-κB pathway, suggesting that it has therapeutic potential for DN.

A Review of Current Trends with Type 2 Diabetes Epidemiology, Aetiology, Pathogenesis, Treatments and Future Perspectives

Type 2 diabetes (T2D), which has currently become a global pandemic, is a metabolic disease largely characterised by impaired insulin secretion and action. Significant progress has been made in understanding T2D aetiology and pathogenesis, which is discussed in this review. Extrapancreatic pathology is also summarised, which demonstrates the highly multifactorial nature of T2D. Glucagon-like peptide (GLP)-1 is an incretin hormone responsible for augmenting insulin secretion from pancreatic beta-cells during the postprandial period. Given that native GLP-1 has a very short half-life, GLP-1 mimetics with a much longer half-life have been developed, which are currently an effective treatment option for T2D by enhancing insulin secretion in patients. Interestingly, there is continual emerging evidence that these therapies alleviate some of the post-diagnosis complications of T2D. Additionally, these therapies have been shown to induce weight loss in patients, suggesting they could be an alternative to bariatric surgery, a procedure associated with numerous complications. Current GLP-1-based therapies all act as orthosteric agonists for the GLP-1 receptor (GLP-1R). Interestingly, it has emerged that GLP-1R also has allosteric binding sites and agonists have been developed for these sites to test their therapeutic potential. Recent studies have also demonstrated the potential of bi- and tri-agonists, which target multiple hormonal receptors including GLP-1R, to more effectively treat T2D. Improved understanding of T2D aetiology/pathogenesis, coupled with the further elucidation of both GLP-1 activity/targets and GLP-1R mechanisms of activation via different agonists, will likely provide better insight into the therapeutic potential of GLP-1-based therapies to treat T2D.

New progress in drugs treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is not only one of the main complications of diabetes, but also the leading cause of the end-stage renal disease (ESRD). The occurrence and development of DKD have always been a serious clinical problem that leads to the increase of morbidity and mortality and the severe damage to the quality of life of human beings. Controlling blood glucose, blood pressure, blood lipids, and improving lifestyle can help slow the progress of DKD. In recent years, with the extensive research on the pathological mechanism and molecular mechanism of DKD, there are more and more new drugs based on this, such as new hypoglycemic drugs sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) inhibitors, and dipeptidyl peptidase-4 (DPP-4) inhibitors with good efficacy in clinical treatment. Besides, there are some newly developed drugs, including protein kinase C (PKC) inhibitors, advanced glycation end product (AGE) inhibitors, aldosterone receptor inhibitors, endothelin receptor (ETR) inhibitors, transforming growth factor-β (TGF-β) inhibitors, Rho kinase (ROCK) inhibitors and so on, which show positive effects in animal or clinical trials and bring hope for the treatment of DKD. In this review, we sort out the progress in the treatment of DKD in recent years, the research status of some emerging drugs, and the potential drugs for the treatment of DKD in the future, hoping to provide some directions for clinical treatment of DKD.