Incretin drugs in diabetic kidney disease: biological mechanisms and clinical evidence

Emerging therapeutic landscape: Incretin agonists in chronic kidney disease management

The increasing incidence of chronic kidney disease (CKD) poses a significant public health concern, prompting heightened attention to its treatment. Incretins, including glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide, are intestinal peptides released after nutrient intake, known for their hypoglycemic effects in diabetes management. Recent advancements highlight the promising outcomes of GLP-1 receptor agonists in reducing CKD risk factors and improving renal outcomes. The multifaceted functions of GLP-1, such as its anti-obesity, anti-hypertensive, anti-hyperglycemic, anti-lipid, anti-inflammatory, and endothelial function protective properties, contribute to its potential as a therapeutic agent for CKD. Although experiments suggest the potential benefits of incretin in CKD, a comprehensive understanding of its specific mechanisms is still lacking. This review aims to provide a detailed examination of current evidence and potential future directions, emphasizing the promising yet evolving landscape of incretin agonists in the context of CKD.

Effects of Semaglutide on Chronic Kidney Disease in Patients with Type 2 Diabetes

BACKGROUND

Patients with type 2 diabetes and chronic kidney disease are at high risk for kidney failure, cardiovascular events, and death. Whether treatment with semaglutide would mitigate these risks is unknown.

METHODS

We randomly assigned patients with type 2 diabetes and chronic kidney disease (defined by an estimated glomerular filtration rate [eGFR] of 50 to 75 ml per minute per 1.73 m2 of body-surface area and a urinary albumin-to-creatinine ratio [with albumin measured in milligrams and creatinine measured in grams] of >300 and <5000 or an eGFR of 25 to <50 ml per minute per 1.73 m2 and a urinary albumin-to-creatinine ratio of >100 and <5000) to receive subcutaneous semaglutide at a dose of 1.0 mg weekly or placebo. The primary outcome was major kidney disease events, a composite of the onset of kidney failure (dialysis, transplantation, or an eGFR of <15 ml per minute per 1.73 m2), at least a 50% reduction in the eGFR from baseline, or death from kidney-related or cardiovascular causes. Prespecified confirmatory secondary outcomes were tested hierarchically.

RESULTS

Among the 3533 participants who underwent randomization (1767 in the semaglutide group and 1766 in the placebo group), median follow-up was 3.4 years, after early trial cessation was recommended at a prespecified interim analysis. The risk of a primary-outcome event was 24% lower in the semaglutide group than in the placebo group (331 vs. 410 first events; hazard ratio, 0.76; 95% confidence interval [CI], 0.66 to 0.88; P = 0.0003). Results were similar for a composite of the kidney-specific components of the primary outcome (hazard ratio, 0.79; 95% CI, 0.66 to 0.94) and for death from cardiovascular causes (hazard ratio, 0.71; 95% CI, 0.56 to 0.89). The results for all confirmatory secondary outcomes favored semaglutide: the mean annual eGFR slope was less steep (indicating a slower decrease) by 1.16 ml per minute per 1.73 m2 in the semaglutide group (P<0.001), the risk of major cardiovascular events 18% lower (hazard ratio, 0.82; 95% CI, 0.68 to 0.98; P = 0.029), and the risk of death from any cause 20% lower (hazard ratio, 0.80; 95% CI, 0.67 to 0.95, P = 0.01). Serious adverse events were reported in a lower percentage of participants in the semaglutide group than in the placebo group (49.6% vs. 53.8%).

CONCLUSIONS

Semaglutide reduced the risk of clinically important kidney outcomes and death from cardiovascular causes in patients with type 2 diabetes and chronic kidney disease. (Funded by Novo Nordisk; FLOW ClinicalTrials.gov number, NCT03819153.).

Combination therapy for kidney disease in people with diabetes mellitus

Diabetic kidney disease (DKD), defined as co-existing diabetes and chronic kidney disease in the absence of other clear causes of kidney injury, occurs in approximately 20-40% of patients with diabetes mellitus. As the global prevalence of diabetes has increased, DKD has become highly prevalent and a leading cause of kidney failure, accelerated cardiovascular disease, premature mortality and global health care expenditure. Multiple pathophysiological mechanisms contribute to DKD, and single lifestyle or pharmacological interventions have shown limited efficacy at preserving kidney function. For nearly two decades, renin-angiotensin system inhibitors were the only available kidney-protective drugs. However, several new drug classes, including sodium glucose cotransporter-2 inhibitors, a non-steroidal mineralocorticoid antagonist and a selective endothelin receptor antagonist, have now been demonstrated to improve kidney outcomes in people with type 2 diabetes mellitus. In addition, emerging preclinical and clinical evidence of the kidney-protective effects of glucagon-like-peptide-1 receptor agonists has led to the prospective testing of these agents for DKD. Research and clinical efforts are geared towards using therapies with potentially complementary efficacy in combination to safely halt kidney disease progression. As more kidney-protective drugs become available, the outlook for people living with DKD should improve in the next few decades.

The role of mitochondrial dysfunction in kidney injury and disease

Mitochondria are the main sites of aerobic respiration in the cell and mainly provide energy for the organism, and play key roles in adenosine triphosphate (ATP) synthesis, metabolic regulation, and cell differentiation and death. Mitochondrial dysfunction has been identified as a contributing factor to a variety of diseases. The kidney is rich in mitochondria to meet energy needs, and stable mitochondrial structure and function are essential for normal kidney function. Recently, many studies have shown a link between mitochondrial dysfunction and kidney disease, maintaining mitochondrial homeostasis has become an important target for kidney therapy. In this review, we integrate the role of mitochondrial dysfunction in different kidney diseases, and specifically elaborate the mechanism of mitochondrial reactive oxygen species (mtROS), autophagy and ferroptosis involved in the occurrence and development of kidney diseases, providing insights for improved treatment of kidney diseases.

Renal effects of GLP-1 receptor agonists and tirzepatide in individuals with type 2 diabetes: seeds of a promising future

PURPOSE

Chronic kidney disease (CKD) is one of the most common complications of type 2 diabetes (T2D), and CKD-related disability and mortality are increasing despite the recent advances in diabetes management. The dual GIP/GLP-1 receptor agonist tirzepatide is among the furthest developed multi-agonists for diabetes care and has so far displayed promising nephroprotective effects. This review aims to summarize the evidence regarding the nephroprotective effects of glucagon-like peptide-1 receptor agonists (GLP-1RA) and tirzepatide and the putative mechanisms underlying the favorable renal profile of tirzepatide.

METHODS

A comprehensive literature search was performed from inception to July 31st 2023 to select research papers addressing the renal effects of GLP-1RA and tirzepatide.

RESULTS

The pathogenesis of CKD in patients with T2D likely involves many contributors besides hyperglycemia, such as hypertension, obesity, insulin resistance and glomerular atherosclerosis, exerting kidney damage through metabolic, fibrotic, inflammatory, and hemodynamic mechanisms. Tirzepatide displayed an unprecedented glucose and body weight lowering potential, presenting also with the ability to increase insulin sensitivity, reduce systolic blood pressure and inflammation and ameliorate dyslipidemia, particularly by reducing triglycerides levels.

CONCLUSION

Tirzepatide is likely to counteract most of the pathogenetic factors contributing to CKD in T2D, potentially representing a step forward in incretin-based therapy towards nephroprotection. Further evidence is needed to understand its role in renal hemodynamics, fibrosis, cell damage and atherosclerosis, as well as to conclusively show reduction of hard renal outcomes.

The potential role of Tirzepatide as adjuvant therapy in countering colistin-induced nephro and neurotoxicity in rats via modulation of PI3K/p-Akt/GSK3-β/NF-kB p65 hub, shielding against oxidative and endoplasmic reticulum stress, and activation of p-CREB/BDNF/TrkB cascade

Although colistin has a crucial antibacterial activity in treating multidrug-resistant gram-negative bacteria strains; it exhibited renal and neuronal toxicities rendering its use a challenge. Previous studies investigated the incretin hormones either glucose-dependent insulinotropic polypeptide (GIP) or glucagonlike peptide-1 (GLP-1) for their neuroprotective and nephroprotective effectiveness. The present study focused on investigating Tirzepatide (Tirze), a dual GLP-1/GIP agonist, as an adjuvant therapy in the colistin treatment protocol for attenuating its renal and neuronal complications. Rats were divided into; The normal control group, the colistin-treated group received colistin (300,000 IU/kg/day for 7 days; i.p.). The Tirze-treated group received Tirze (1.35 mg/kg on the 1,4,7thdays; s.c.) and daily colistin. Tirze effectively enhanced histopathological alterations, renal function parameters, and locomotor activity in rats. Tirze mechanistically acted via modulating various signaling axes evolved under the insult of phosphatidylinositol 3-kinases (PI3K)/phosphorylated protein kinase-B (p-Akt)/ glycogen synthase kinase (GSK)3-β hub causing mitigation of nuclear factor (NF)-κB (NF-κB) / tumor necrosis factor-α (TNF-α), increment of nuclear factor erythroid 2-related factor 2 (Nrf2)/ glutathione (GSH), downregulation of ER stress-related biomarkers (activation transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP)), antiapoptotic effects coupling with reduction of glial fibrillary acidic protein (GFAP) immunoreactivity and enhancement of phosphorylated c-AMP response element-binding (p-CREB) / brain-derived neurotrophic factor (BDNF)/tyrosine kinase B (TrkB) neuroprotective pathway. Briefly, Tirze exerts a promising role as adjuvant therapy in the colistin treatment protocol for protection against colistin's nephro- and neurotoxicity according to its anti-inflammatory, antioxidant, and antiapoptotic impacts besides its ability to suppress ER stress-related biomarkers.

Molecular Targets of Novel Therapeutics for Diabetic Kidney Disease: A New Era of Nephroprotection

Diabetic kidney disease (DKD) is a chronic microvascular complication in patients with diabetes mellitus (DM) and the leading cause of end-stage kidney disease (ESKD). Although glomerulosclerosis, tubular injury and interstitial fibrosis are typical damages of DKD, the interplay of different processes (metabolic factors, oxidative stress, inflammatory pathway, fibrotic signaling, and hemodynamic mechanisms) appears to drive the onset and progression of DKD. A growing understanding of the pathogenetic mechanisms, and the development of new therapeutics, is opening the way for a new era of nephroprotection based on precision-medicine approaches. This review summarizes the therapeutic options linked to specific molecular mechanisms of DKD, including renin-angiotensin-aldosterone system blockers, SGLT2 inhibitors, mineralocorticoid receptor antagonists, glucagon-like peptide-1 receptor agonists, endothelin receptor antagonists, and aldosterone synthase inhibitors. In a new era of nephroprotection, these drugs, as pillars of personalized medicine, can improve renal outcomes and enhance the quality of life for individuals with DKD.

Cardiovascular and Kidney Risks in Individuals With Type 2 Diabetes: Contemporary Understanding With Greater Emphasis on Excess Adiposity

In high-income countries, rates of atherosclerotic complications in type 2 diabetes have declined markedly over time due to better management of traditional risk factors including lipids, blood pressure, and glycemia levels. Population-wide reductions in smoking have also helped lower atherosclerotic complications and so reduce premature mortality in type 2 diabetes. However, as excess adiposity is a stronger driver for heart failure (HF), and obesity levels have remained largely unchanged, HF risks have not declined as much and may even be rising in the increasing number of people developing type 2 diabetes at younger ages. Excess weight is also an underrecognized risk factor for chronic kidney disease (CKD). Based on evidence from a range of sources, we explain how excess adiposity must be influencing most risks well before diabetes develops, particularly in younger-onset diabetes, which is linked to greater excess adiposity. We also review potential mechanisms linking excess adiposity to HF and CKD and speculate on how some of the responsible pathways-e.g., hemodynamic, cellular overnutrition, and inflammatory-could be favorably influenced by intentional weight loss (via lifestyle or drugs). On the basis of available evidence, we suggest that the cardiorenal outcome benefits seen with sodium-glucose cotransporter 2 inhibitors may partially derive from their interference of some of these same pathways. We also note that many other complications common in diabetes (e.g., hepatic, joint disease, perhaps mental health) are also variably linked to excess adiposity, the aggregated exposure to which has now increased in type 2 diabetes. All such observations suggest a greater need to tackle excess adiposity earlier in type 2 diabetes.

A New Hope on the Horizon for Kidney and Cardiovascular Protection with SGLT2 Inhibitors, GLP-1 Receptor Agonists, and Mineralocorticoid Receptor Antagonists in Type 2 Diabetic and Chronic Kidney Disease Patients

Type 2 diabetes (T2D) is the leading cause of chronic kidney disease (CKD). In addition, the cardiovascular prevalence in diabetic patients is around 32.2%, with a two-fold increased mortality risk compared to those without diabetes. Recent investigations have shed light on the promising cardioprotective and nephroprotective benefits of sodium-glucose cotransporter-2 inhibitors (SGLT2i), glucagon-like peptide-1 receptor agonists (GLP-1RA), and nonsteroidal mineralocorticoid receptor antagonists (nsMRAs) for individuals with T2D. The evidence robustly indicates that SGLT2i and GLP-1RA significantly reduce the risk of CKD and cardiovascular disease (CVD), all while effectively managing blood glucose levels. Furthermore, combining SGLT2i with nsMRAs amplifies the benefits, potentially offering a more profound reduction in cardiovascular and renal outcomes. The data analysis strongly supports the integration of these pharmacological agents in the management strategies for CKD and CVD prevention among T2D patients, highlighting the importance of awareness among nephrologists, especially in regions with limited healthcare resources.

Novel Perspectives in Chronic Kidney Disease-Specific Cardiovascular Disease

Chronic kidney disease (CKD) affects > 10% of the global adult population and significantly increases the risk of cardiovascular disease (CVD), which remains the leading cause of death in this population. The development and progression of CVD-compared to the general population-is premature and accelerated, manifesting as coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. CKD and CV disease combine to cause multimorbid cardiorenal syndrome (CRS) due to contributions from shared risk factors, including systolic hypertension, diabetes mellitus, obesity, and dyslipidemia. Additional neurohormonal activation, innate immunity, and inflammation contribute to progressive cardiac and renal deterioration, reflecting the strong bidirectional interaction between these organ systems. A shared molecular pathophysiology-including inflammation, oxidative stress, senescence, and hemodynamic fluctuations characterise all types of CRS. This review highlights the evolving paradigm and recent advances in our understanding of the molecular biology of CRS, outlining the potential for disease-specific therapies and biomarker disease detection.

Metabolic hormones are integral regulators of female reproductive health and function

The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.

Kidney Fibrosis and Oxidative Stress: From Molecular Pathways to New Pharmacological Opportunities

Kidney fibrosis, diffused into the interstitium, vessels, and glomerulus, is the main pathologic feature associated with loss of renal function and chronic kidney disease (CKD). Fibrosis may be triggered in kidney diseases by different genetic and molecular insults. However, several studies have shown that fibrosis can be linked to oxidative stress and mitochondrial dysfunction in CKD. In this review, we will focus on three pathways that link oxidative stress and kidney fibrosis, namely: (i) hyperglycemia and mitochondrial energy imbalance, (ii) the mineralocorticoid signaling pathway, and (iii) the hypoxia-inducible factor (HIF) pathway. We selected these pathways because they are targeted by available medications capable of reducing kidney fibrosis, such as sodium-glucose cotransporter-2 (SGLT2) inhibitors, non-steroidal mineralocorticoid receptor antagonists (MRAs), and HIF-1alpha-prolyl hydroxylase inhibitors. These drugs have shown a reduction in oxidative stress in the kidney and a reduced collagen deposition across different CKD subtypes. However, there is still a long and winding road to a clear understanding of the anti-fibrotic effects of these compounds in humans, due to the inherent practical and ethical difficulties in obtaining sequential kidney biopsies and the lack of specific fibrosis biomarkers measurable in easily accessible matrices like urine. In this narrative review, we will describe these three pathways, their interconnections, and their link to and activity in oxidative stress and kidney fibrosis.

Glucagon-like peptide-1 receptor agonists for the management of diabetic peripheral neuropathy

Diabetes mellitus is a prevalent chronic disease characterized by hyperglycemia. Diabetic peripheral neuropathy (DPN) is one of the complications of diabetes mellitus and is caused by neuron injury induced by hyperglycemic circumstances. The incidence of DPN varies among different countries and regions, ranging from nearly 20% to over 70%. Patients with DPN may encounter symmetric pain or discomfort of the extremes, leading to reduced quality of life and even amputation. The pharmacological management for painful DPN mainly includes antidepressants due to their analgesic effects. Nevertheless, effective therapies to impact the pathogenesis and progression of DPN are lacking. Glucagon-like peptide-1 receptor (GLP-1R) agonists show efficacy in controlling blood glucose and serve as a treatment modality for diabetes mellitus. In recent years, evidence has been proposed that GLP-1R agonists exert neuroprotective effects through modulating inflammation, oxidative stress, and mitochondrial dysfunction. On the other hand, clinical evidence on the potential of GLP-1R agonists for treating DPN is still controversial and limited. This narrative review summarizes the preclinical and clinical studies investigating the capacity of GLP-1R agonists as therapeutic agents for DPN.

(Pro)renin receptor mediates tubular epithelial cell pyroptosis in diabetic kidney disease via DPP4-JNK pathway

BACKGROUND

(Pro)renin receptor (PRR) is highly expressed in renal tubules, which is involved in physiological and pathological processes. However, the role of PRR, expressed in renal tubular epithelial cells, in diabetic kidney disease (DKD) remain largely unknown.

METHODS

In this study, kidney biopsies, urine samples, and public RNA-seq data from DKD patients were used to assess PRR expression and cell pyroptosis in tubular epithelial cells. The regulation of tubular epithelial cell pyroptosis by PRR was investigated by in situ renal injection of adeno-associated virus9 (AAV9)-shRNA into db/db mice, and knockdown or overexpression of PRR in HK-2 cells. To reveal the underlined mechanism, the interaction of PRR with potential binding proteins was explored by using BioGrid database. Furthermore, the direct binding of PRR to dipeptidyl peptidase 4 (DPP4), a pleiotropic serine peptidase which increases blood glucose by degrading incretins under diabetic conditions, was confirmed by co-immunoprecipitation assay and immunostaining.

RESULTS

Higher expression of PRR was found in renal tubules and positively correlated with kidney injuries of DKD patients, in parallel with tubular epithelial cells pyroptosis. Knockdown of PRR in kidneys significantly blunted db/db mice to kidney injury by alleviating renal tubular epithelial cells pyroptosis and the resultant interstitial inflammation. Moreover, silencing of PRR blocked high glucose-induced HK-2 pyroptosis, whereas overexpression of PRR enhanced pyroptotic cell death of HK-2 cells. Mechanistically, PRR selectively bound to cysteine-enrich region of C-terminal of DPP4 and augmented the protein abundance of DPP4, leading to the downstream activation of JNK signaling and suppression of SIRT3 signaling and FGFR1 signaling, and then subsequently mediated pyroptotic cell death.

CONCLUSIONS

This study identified the significant role of PRR in the pathogenesis of DKD; specifically, PRR promoted tubular epithelial cell pyroptosis via DPP4 mediated signaling, highlighting that PRR could be a promising therapeutic target in DKD.

Optimization of guideline-directed medical therapies in patients with diabetes and chronic kidney disease

Diabetes is the leading cause of chronic kidney disease (CKD) and kidney failure worldwide. CKD frequently coexists with heart failure and atherosclerotic cardiovascular disease in the broader context of cardio-kidney-metabolic syndrome. Diabetes and CKD are associated with increased risk of all-cause and cardiovascular death as well as decreased quality of life. The role of metabolic and hemodynamic abnormalities has long been recognized as an important contributor to the pathogenesis and progression of CKD in diabetes, while a more recent and growing body of evidence supports activation of both systemic and local inflammation as important contributors. Current guidelines recommend therapies targeting pathomechanisms of CKD in addition to management of traditional risk factors such as hyperglycemia and hypertension. Sodium-glucose cotransporter-2 inhibitors are recommended for treatment of patients with CKD and type 2 diabetes (T2D) if eGFR is ≥20 ml/min/173 m2 on a background of renin-angiotensin system inhibition. For patients with T2D, CKD, and atherosclerotic cardiovascular disease, a glucagon-like peptide-1 receptor agonist is recommended as additional risk-based therapy. A non-steroidal mineralocorticoid receptor antagonist is also recommended as additional risk-based therapy for persistent albuminuria in patients with T2D already treated with renin-angiotensin system inhibition. Implementation of guideline-directed medical therapies is challenging in the face of rapidly accumulating knowledge, high cost of medications, and lack of infrastructure for optimal healthcare delivery. Furthermore, studies of new therapies have focused on T2D and CKD. Clinical trials are now planned to inform the role of these therapies in people with type 1 diabetes (T1D) and CKD.

Incretin Therapies for Patients with Type 2 Diabetes and Chronic Kidney Disease

Since the early 2000s, an influx of novel glucose-lowering agents has changed the therapeutic landscape for treatment of diabetes and diabetes-related complications. Glucagon-like peptide-1 (GLP-1) receptor agonists represent an important therapeutic class for the management of type 2 diabetes (T2D), demonstrating benefits beyond glycemic control, including lowering of blood pressure and body weight, and importantly, decreased risk of development of new or worsening chronic kidney disease (CKD) and reduced rates of atherosclerotic cardiovascular events. Plausible non-glycemic mechanisms that benefit the heart and kidneys with GLP-1 receptor agonists include anti-inflammatory and antioxidant effects. Further supporting their use in CKD, the glycemic benefits of GLP-1 receptor agonists are preserved in moderate-to-severe CKD. Considering current evidence, major guideline-forming organizations recommend the use of GLP-1 receptor agonists in cases of T2D and CKD, especially in those with obesity and/or in those with high cardiovascular risk or established heart disease. Evidence continues to build that supports benefits to the heart and kidneys of the dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) receptor agonist tirzepatide. Ongoing outcome and mechanistic studies will continue to inform our understanding of the role of GLP-1 and dual GLP-1/GIP receptor agonists in diverse patient populations with kidney disease.

[Advantages of glucagon-like peptide-1 receptor agonists in the treatment of patients with type 2 diabetes mellitus: A review]

Glucagon-like peptide-1 receptor agonists (arGLP1) are an effective treatment for patients with type 2 diabetes mellitus (T2DM), mainly due to increasing insulin secretion and suppressing glucagon release by stimulating the respective receptors. Taking into account their positive effect on major cardiovascular events, drugs in this group with proven cardioprotective effects are recommended for patients with T2DM and clinical cardiovascular diseases or multiple cardiovascular risk factors. In this paper, we present an overview of current clinical studies on the clinical efficacy and safety of arGLP1 and discuss current prospects for arGLP1 as a therapy for patients with T2DM.

Inulin Inhibits the Inflammatory Response through Modulating Enteric Glial Cell Function in Type 2 Diabetic Mellitus Mice by Reshaping Intestinal Flora

Inulin, a commonly used dietary fiber supplement, is capable of modulating the gut microbiome. Chronic inflammation resulting from metabolic abnormalities and gut flora dysfunction plays a significant role in the development of type 2 diabetes mellitus (T2DM). Our research has demonstrated that inulin administration effectively reduced colonic inflammation in T2DM mice by inducing changes in the gut microbiota and increasing the concentration of butyric acid, which in turn modulated the function of enteric glial cells (EGCs). Experiments conducted on T2DM mice revealed that inulin administration led to an increase in the Bacteroidetes/Firmicutes ratio and the concentration of butyric acid in the colon. The anti-inflammatory effects of altered gastrointestinal flora and its metabolites were further confirmed through fecal microbiota transplantation. Butyric acid was found to inhibit the activation of the κB inhibitor kinase β/nuclear factor κB pathway, regulate the expression levels of interleukin-6 and tumor necrosis factor-α, suppress the abnormal activation of EGCs, and prevent the release of inflammatory factors by EGCs. Similar results were observed in vitro experiments with butyric acid. Our findings demonstrate that inulin, by influencing the intestinal flora, modifies the activity of EGCs to effectively reduce colonic inflammation in T2DM mice.

Sinensetin ameliorates high glucose-induced diabetic nephropathy via enhancing autophagy in vitro and in vivo

Diabetic nephropathy (DN) affects around 40% of people with diabetes, the final outcome of which is end-stage renal disease. The deficiency of autophagy and excessive oxidative stress have been found to participate in the pathogenesis of DN. Sinensetin (SIN) has been proven to have strong antioxidant capability. However, the effect of SIN on DN has not been studied. We examined the effect of SIN on cell viability and autophagy in the podocyte cell line, MPC5 cells, treated with high glucose (HG). For in vivo studies, DN mice models were established by intraperitoneal injected with streptozotocin (40 mg/kg) for 5 consecutive days and fed with a 60% high-fat diet, and SIN was given (10, 20, and 40 mg/kg) for 8 weeks via intraperitoneal injection. The results showed that SIN could protect MPC5 cells against HG-induced damage and significantly improve the renal function of DN mice. Moreover, SIN remarkably restored the autophagy activity of MPC5 cells which was inhibited under HG conditions. Consistent with this, SIN efficiently improved autophagy in the kidney tissue of DN mice. In brief, our findings demonstrated the protective effect of SIN on DN via restoring the autophagic function, which might provide a basis for drug development.

The rationale, design and baseline data of FLOW, a kidney outcomes trial with once-weekly semaglutide in people with type 2 diabetes and chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a common complication of type 2 diabetes (T2D). Glucagon-like peptide-1 receptor agonists (GLP-1RAs) improve glycaemic control and lower body weight in people with T2D, and some reduce the risk of cardiovascular (CV) events in those with high CV risk. GLP-1RAs might also have kidney-protective effects. We report the design and baseline data for FLOW (NCT03819153), a trial investigating the effects of semaglutide, a once-weekly (OW) GLP-1RA, on kidney outcomes in participants with CKD and T2D.

METHODS

FLOW is a randomised, double-blind, parallel-group, multinational, phase 3b trial. Participants with T2D, estimated glomerular filtration rate (eGFR) ≥50‒≤75 ml/min/1.73 m2 and urine albumin:creatinine ratio (UACR) >300‒<5000 mg/g or eGFR ≥25‒<50 ml/min/1.73 m2 and UACR >100‒<5000 mg/g were randomised 1:1 to OW semaglutide 1.0 mg or matched placebo, with renin-angiotensin-aldosterone system blockade (unless not tolerated/contraindicated). The composite primary endpoint is time to first kidney failure (persistent eGFR <15 ml/min/1.73 m2 or initiation of chronic kidney replacement therapy), persistent ≥50% reduction in eGFR or death from kidney or CV causes.

RESULTS

Enrolled participants (N = 3534) had a baseline mean age of 66.6 years [standard deviation (SD) 9.0], haemoglobin A1c of 7.8% (SD 1.3), diabetes duration of 17.4 years (SD 9.3), eGFR of 47.0 ml/min/1.73 m2 (SD 15.2) and median UACR of 568 mg/g (range 2‒11 852). According to Kidney Disease: Improving Global Outcomes guidelines categorisation, 68.2% were at very high risk for CKD progression.

CONCLUSION

FLOW will evaluate the effect of semaglutide on kidney outcomes in participants with CKD and T2D, and is expected to be completed in late 2024.

Antioxidant nanozymes in kidney injury: mechanism and application

Excessive production of reactive oxygen species (ROS) in the kidneys is involved in the pathogenesis of kidney diseases, such as acute kidney injury (AKI) and diabetic kidney disease (DKD), and is the main reason for the progression of kidney injury. ROS can easily lead to lipid peroxidation and damage the tubular epithelial cell membrane, proteins and DNA, and other molecules, which can trigger cellular oxidative stress. Effective scavenging of ROS can delay or halt the progression of kidney injury by reducing inflammation and oxidative stress. With the development of nanotechnology and an improved understanding of nanomaterials, more researchers are applying nanomaterials with antioxidant activity to treat kidney injury. This article reviews the detailed mechanism between ROS and kidney injury, as well as the applications of nanozymes with antioxidant effects based on different materials for various kidney injuries. To better guide the applications of antioxidant nanozymes in kidney injury and other inflammatory diseases, at the end of this review we also summarize the aspects of nanozymes that need to be improved. An in-depth understanding of the role played by ROS in the occurrence and progression of kidney injury and the mechanism by which antioxidant nanozymes reduce oxidative stress is conducive to improving the therapeutic effect in kidney injury and inflammation-related diseases.

The effect of Dipeptidyl peptidase 4 (DPP-4) inhibitors on hemoglobin level in diabetic kidney disease: A retrospective cohort study

Anemia typically develops early in the course of diabetic kidney disease (DKD). There are data to show that dipeptidyl-peptidase-4 (DPP-4) inhibitors affect hematopoietic growth factor activity and hemoglobin level. We retrospectively reviewed 443 DKD patients who were started on DDP-4 inhibitor therapy in 2019. Their hemoglobin level at baseline (6-12 months before treatment), pretreatment (0-6 months before treatment), and post-treatment periods (within 6 months after DPP-4 inhibitor), concomitant estimated glomerular filtration rate (eGFR), HbA1c, peripheral blood white cell and platelet counts were reviewed. The severity of kidney failure was classified according to the Kidney Disease: Improving Global Outcomes stages. The hemoglobin level had a small but significant decline from 11.98 ± 2.07 to 11.87 ± 2.12 g/dL from pretreatment to post-treatment period (paired Student t test, P < .0001). From the pre- to post-treatment period, the decline of hemoglobin level was 0.10 ± 0.89 g/dL, which was significantly less than that from baseline to pretreatment period (0.24 ± 0.90 g/dL, P = .0008). The change in hemoglobin level had a positive correlation with the change in HbA1c level (R = 0.218, P < .0001), but did not correlate with the type of DPP-4 inhibitor or pretreatment eGFR. There was no significant change in peripheral blood white cell or platelet count during the same period. DPP-4 inhibitor ameliorates hemoglobin decline in DKD. The effect of DPP-4 inhibitor on hemoglobin is statistically significant but clinically modest, and did not correlate with the concomitant change in kidney function.

The cardio-renal-metabolic connection: a review of the evidence

Type 2 diabetes (T2D), cardiovascular disease (CVD) and chronic kidney disease (CKD), are recognized among the most disruptive public health issues of the current century. A large body of evidence from epidemiological and clinical research supports the existence of a strong interconnection between these conditions, such that the unifying term cardio-metabolic-renal (CMR) disease has been defined. This coexistence has remarkable epidemiological, pathophysiologic, and prognostic implications. The mechanisms of hyperglycemia-induced damage to the cardio-renal system are well validated, as are those that tie cardiac and renal disease together. Yet, it remains controversial how and to what extent CVD and CKD can promote metabolic dysregulation. The aim of this review is to recapitulate the epidemiology of the CMR connections; to discuss the well-established, as well as the putative and emerging mechanisms implicated in the interplay among these three entities; and to provide a pathophysiological background for an integrated therapeutic intervention aiming at interrupting this vicious crosstalks.

Mechanism of preventive effects of exendin-4 and des-fluoro-sitagliptin in a murine model of fructose-induced prediabetes

Protective effects of exendin-4 (glucagon-like peptide-1 -GLP-1- receptor agonist) and des-fluoro-sitagliptin (dipeptidyl peptidase-4 inhibitor) on fructose-induced hepatic disturbances were evaluated in prediabetic rats. Complementary, a possible direct effect of exendin-4 in human hepatoblastoma-derived cell line HepG2 incubated with fructose in presence/absence of exendin-9-39 (GLP-1 receptor antagonist) was investigated. In vivo, after 21 days of fructose rich diet, we determined: glycemia, insulinemia, and triglyceridemia; hepatic fructokinase, AMP-deaminase, and G-6-P dehydrogenase (G-6-P DH) activities; carbohydrate-responsive element-binding protein (ChREBP) expression; triglyceride content and lipogenic gene expression (glycerol-3-phosphate acyltransferase -GPAT-, fatty acid synthase -FAS-, sterol regulatory element-binding protein-1c -SREBP-1c); oxidative stress and inflammatory markers expression. In HepG2 cells we measured fructokinase activity and triglyceride content. Hypertriglyceridemia, hyperinsulinemia, enhanced liver fructokinase, AMP-deaminase, and G-6-P DH activities, increased ChREBP and lipogenic genes expression, enhanced triglyceride level, oxidative stress and inflammatory markers recorded in fructose fed animals, were prevented by co-administration of either exendin-4 or des-fluoro-sitagliptin. Exendin-4 prevented fructose-induced increase in fructokinase activity and triglyceride contain in HepG2 cells. These effects were blunted co-incubating with exendin-9-39. The results demonstrated for the first time that exendin-4/des-fluro-sitagliptin prevented fructose-induced endocrine-metabolic oxidative stress and inflammatory changes probably acting on the purine degradation pathway. Exendin 9-39 blunted in vitro protective exendin-4 effects, thereby suggesting a direct effect of this compound on hepatocytes through GLP-1 receptor. Direct effect on fructokinase and AMP-deaminase activities, with a key role in the pathogenesis of liver dysfunction induced by fructose, suggests purine degradation pathway constitute a potential therapeutic objective for GLP-1 receptor agonists.

Glucagon-like peptide 1(GLP-1) receptor agonists in the management of the patient with type 2diabetes mellitus and chronic kidney disease: an approach for the nephrologist

Diabetic kidney disease, a common complication in patients with type 2 diabetes mellitus, is associated with a markedly increased morbidity and mortality, especially of cardiovascular origin, and faster progression to end-stage renal disease. To date, reducing cardiovascular and renal risk in this population was based on strict control of cardiovascular risk factors and the renin-angiotensin system blockade. More recently, sodium-glucose cotransporter type 2 inhibitors have demonstrated to offer cardiovascular and renal protection, but the residual risk remains high and their antihyperglycemic efficacy is limited in moderate-severe CKD. Therefore, drugs with a potent antihyperglycemic effect, independent of the glomerular filtration rate, with a low risk of hypoglycemia, that reduce weight in overweight/obese patients and that provide cardiovascular and renal protection, such as GLP-1 receptor agonists, are needed. However, these drugs require subcutaneous administration, which may limit their early use. The recent availability of oral semaglutide may facilitate the early introduction of this family with proven cardiovascular and renal benefits and excellent safety profile. In this review the family is analyzed as well as their cardiovascular and renal effects.

Mechanisms and clinical applications of incretin therapies for diabetes and chronic kidney disease

PURPOSE OF REVIEW

Diabetic kidney disease (DKD) is the leading cause of kidney failure worldwide. Development of DKD increases risks for cardiovascular events and death. Glucagon-like peptide-1 (GLP-1) receptor agonist have demonstrated improved cardiovascular and kidney outcomes in large-scale clinical trials.

RECENT FINDING

GLP-1 and dual GLP-1/glucose-depending insulinotropic polypeptide (GIP) receptor agonists have robust glucose-lowering efficacy with low risk of hypoglycemia even in advanced stages of DKD. Initially approved as antihyperglycemic therapies, these agents also reduce blood pressure and body weight. Cardiovascular outcome and glycemic lowering trials have reported decreased risks of development and progression of DKD and atherosclerotic cardiovascular events for GLP-1 receptor agonists. Kidney and cardiovascular protection is mediated partly, but not entirely, by lowering of glycemia, body weight, and blood pressure. Experimental data have identified modulation of the innate immune response as a biologically plausible mechanism underpinning kidney and cardiovascular effects.

SUMMARY

An influx of incretin-based therapies has changed the landscape of DKD treatment. GLP-1 receptor agonist use is endorsed by all major guideline forming organizations. Ongoing clinical trials and mechanistic studies with GLP-1 and dual GLP-1/GIP receptor agonists will further define the roles and pathways for these agents in the treatment of DKD.

Finerenone: towards a holistic therapeutic approach to patients with diabetic kidney disease

Despite current treatments, which include renin angiotensin system blockers and SGLT2 inhibitors, the risk of progression of kidney disease among patients with diabetes and chronic kidney disease (CKD) remains unacceptably high. The pathogenesis of CKD in patients with diabetes is complex and includes hemodynamic and metabolic factors, as well as inflammation and fibrosis. Finerenone is a highly selective nonsteroidal mineralocorticoid antagonist that, in contrast to current therapies, may directly reduce inflammation and fibrosis, thus adding value in the management of these patients. In fact, finerenone decreases albuminuria and slows CKD progression in persons with diabetes. We now review the mechanisms of action of finerenone, the results of recent clinical trials, and the integration of the kidney and cardiovascular protection afforded by finerenone in the routine care of patients with diabetes and CKD.

Tirzepatide and potential use for metabolically healthy obesity

Metabolically healthy obesity or metabolically healthy overweight (MHO) is best described as being absent of any major metabolic disorder or cardiovascular diseases such as type 2 diabetes mellitus, dyslipidemia, hypertension, and atherosclerotic cardiovascular disease despite being obese or overweight. Nevertheless, MHO is being recognized as an important risk factor for the development of cardiovascular, cerebrovascular, and peripheral artery disease. In addition, these patients are at a high risk of conversion to the metabolically unhealthy phenotype. Tirzepatide is a newly developed glucose-lowering agent which acts on the glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. It has been shown to result in several highly beneficial outcomes including weight loss and a significant improvement in important metabolic parameters such as HbA1c, fasting serum glucose, and triglyceride/lipoprotein levels. These findings suggest that tirzepatide could potentially be beneficial to metabolically healthy obese or metabolically healthy overweight patients in reducing their risk of adverse cardiovascular outcomes and conversion to the metabolically unhealthy phenotype. In this review, we aim to discuss the potential benefits of using the novel anti-diabetic tirzepatide in the management of MHO to prevent the development of cardiovascular events and to decrease the likelihood of conversion to the unhealthy phenotype. We initially describe the clinical outcomes of MHO as well as the association of MHO with developing future cardiovascular events. We then delineate the currently available evidence behind the clinical effects of tirzepatide. We finally discuss the potential advantages of using tirzepatide in the management of MHO.

Highly water-soluble diacetyl chrysin ameliorates diabetes-associated renal fibrosis and retinal microvascular abnormality in db/db mice

BACKGROUND/OBJECTIVES

Chronic or intermittent hyperglycemia is associated with the development of diabetic complications. Oxidative stress and inflammation can be altered by hyperglycemia in diverse tissues, including kidneys and eyes, and play a pivotal role in diabetic complications. Our previous studies showed that the water-insoluble 5,7-dihydroxyflvone chrysin effectively combats diabetic damages incurred in diabetic kidneys and retinas. The current study employed the newly-synthesized 5.7-di-O-acetylchrysin, having higher solubility than chrysin, to compare the effects on diabetes-associated renal fibrosis and abnormal retinal neovascularization.

MATERIALS/METHODS

In the in vivo study, db/db mice as animal models of type 2 diabetes were orally administrated 10 mg/kg BW diacetylchrysin, daily for 10 weeks.

RESULTS

Unlike chrysin, oral administration of 10 mg/kg diacetylchrysin did not lower the blood glucose level and 24 h urine volume in db/db mice. Nevertheless, the urinary albumin excretion was markedly reduced. The administration of diacetylchrysin also diminished the deposition of collagen fibers in diabetic glomeruli and tubules by suppressing the induction of connective tissue growth factor and collagen IV in diabetic kidneys. Supplying diacetylchrysin enhanced the membrane type-1 matrix metalloproteinase (MMP) expression reduced in diabetic kidneys, while the tissue inhibitor of MMP-2 induction was attenuated in diacetylchrysin-challenged diabetic kidneys. In addition, supplementing diacetylchrysin to diabetic mice ameliorated renal injury due to glomerulosclerosis and tubular interstitial fibrosis. Furthermore, the reduced retinal inductions of Zonula occludens-1 and vascular endothelial cadherin in db/db mice were elevated in the retinal tissues of diacetylchrysin-treated animals. Oral administration of diacetylchrysin curtailed the induction of vascular endothelial growth factor (VEGF) and VEGF receptor 2 in db/db mice, ultimately retarding diabetes-associated retinal neovascularization. Additionally, the retinal formation of acellular capillaries with leaky vessels was reduced in diacetylchrysin-treated db/db mice.

CONCLUSION

Diacetylchrysin may act as a potent pro-health agent for treating renal fibrosis-associated diabetic nephropathy and retinal neovascularization-associated diabetic retinopathy.

An international Delphi consensus statement on metabolic dysfunction-associated fatty liver disease and risk of chronic kidney disease

BACKGROUND

With the rising global prevalence of fatty liver disease related to metabolic dysfunction, the association of this common liver condition with chronic kidney disease (CKD) has become increasingly evident. In 2020, the more inclusive term metabolic dysfunction-associated fatty liver disease (MAFLD) was proposed to replace the term non-alcoholic fatty liver disease (NAFLD). The observed association between MAFLD and CKD and our understanding that CKD can be a consequence of underlying metabolic dysfunction support the notion that individuals with MAFLD are at higher risk of having and developing CKD compared with those without MAFLD. However, to date, there is no appropriate guidance on CKD in individuals with MAFLD. Furthermore, there has been little attention paid to the link between MAFLD and CKD in the Nephrology community.

METHODS AND RESULTS

Using a Delphi-based approach, a multidisciplinary panel of 50 international experts from 26 countries reached a consensus on some of the open research questions regarding the link between MAFLD and CKD.

CONCLUSIONS

This Delphi-based consensus statement provided guidance on the epidemiology, mechanisms, management and treatment of MAFLD and CKD, as well as the relationship between the severity of MAFLD and risk of CKD, which establish a framework for the early prevention and management of these two common and interconnected diseases.

Glucagon-like peptide-1 receptor agonists in diabetic kidney disease: A review of their kidney and heart protection

Importance

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of morbidity and mortality for patients with type 2 diabetes (T2D) and chronic kidney disease (CKD). However, testing for albuminuria among patients with T2D is substantially underutilized in clinical practice; many patients with CKD go unrecognized. For patients with T2D at high cardiovascular risk, or with established CVD, the glucagon-like peptide-1 receptor agonists (GLP1-RA) have been shown to reduce ASCVD in cardiovascular outcome trials, while potential kidney outcomes are being explored.

Observations

A recent meta-analysis found that GLP1-RA reduced 3-point major adverse cardiovascular events by 14% [HR, 0.86 (95% CI, 0.80-0.93)] in patients with T2D. The benefits of GLP1-RA to reduce ASCVD were at least as large among people with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². GLP1-RA also conferred a 21% reduction in the composite kidney outcome [HR, 0.79 (0.73-0.87)]; however, this result was achieved largely through reduction in albuminuria. It remains uncertain whether GLP1-RA would confer similar favorable results for eGFR decline and/or progression to end-stage kidney disease. Postulated mechanisms by which GLP1-RA confer protection against CVD and CKD include blood pressure lowering, weight loss, improved glucose control, and decreasing oxidative stress. Ongoing studies in T2D and CKD include a kidney outcome trial with semaglutide (FLOW, NCT03819153) and a mechanism of action study (REMODEL, NCT04865770) examining semaglutide's effect on kidney inflammation and fibrosis. Ongoing cardiovascular outcome studies are examining an oral GLP1-RA (NCT03914326), GLP1-RA in patients without T2D (NCT03574597), and dual GIP/GLP1-RA agonists (NCT04255433); the secondary kidney outcomes of these trials will be informative.

Conclusions and relevance

Despite their well-described ASCVD benefits and potential kidney protective mechanisms, GLP1-RA remain underutilized in clinical practice. This highlights the need for cardiovascular clinicians to influence and implement use of GLP1-RA in appropriate patients, including those with T2D and CKD at higher risk for ASCVD.

Stem cell-derived exosomal MicroRNAs: Potential therapies in diabetic kidney disease

The diabetic kidney disease (DKD) is chronic kidney disease caused by diabetes and one of the most common comorbidities. It is often more difficult to treat end-stage renal disease once it develops because of its complex metabolic disorders, so early prevention and treatment are important. However, currently available DKD therapies are not ideal, and novel therapeutic strategies are urgently needed. The potential of stem cell therapies partly depends on their ability to secrete exosomes. More and more studies have shown that stem cell-derived exosomes take part in the DKD pathophysiological process, which may offer an effective therapy for DKD treatment. Herein, we mainly review potential therapies of stem cell-derived exosomes mainly stem cell-derived exosomal microRNAs in DKD, including their protective effects on mesangial cells, podocytes and renal tubular epithelial cells. Using this secretome as possible therapeutic drugs without potential carcinogenicity should be the focus of further research.

Metabolically healthy obesity: Misleading phrase or healthy phenotype?

Obesity is a heterogenous condition with multiple different phenotypes. Among these a particular subtype exists named as metabolically healthy obesity (MHO). MHO has multiple definitions and its prevalence varies according to study. The potential mechanisms underlying the pathophysiology of MHO include the different types of adipose tissue and their distribution, the role of hormones, inflammation, diet, the intestinal microbiota and genetic factors. In contrast to the negative metabolic profile associated with metabolically unhealthy obesity (MUO), MHO has relatively favorable metabolic characteristics. Nevertheless, MHO is still associated with many important chronic diseases including cardiovascular disease, hypertension, type 2 diabetes, chronic kidney disease as well as certain types of cancer and has the risk of progression into the unhealthy phenotype. Therefore, it should not be considered as a benign condition. The major therapeutic alternatives include dietary modifications, exercise, bariatric surgery and certain medications including glucagon-like peptide-1 (GLP-1) analogs, sodium-glucose cotransporter-2 (SGLT-2) inhibitors and tirzepatide. In this review, we discuss the significance of MHO while comparing this phenotype with MUO.

Incorporating Evidence and Guidelines for Personalized Care of Diabetes and Chronic Kidney Disease

Chronic kidney disease (CKD) represents a particularly challenging diabetes complication. Diabetes now is responsible for half of all cases of CKD, thus making diabetes the most common cause of kidney failure worldwide. In patients with diabetes, CKD frequently coexists with heart failure and atherosclerotic cardiovascular disease, which together are associated with marked increases in the risk of cardiovascular and all-cause mortality. Fortunately, new therapeutic agents from several classes now are available with proven benefits for kidney and heart protection when used in patients with type 2 diabetes and CKD. Agents from the sodium-glucose cotransporter-2 inhibitor, glucagon-like peptide-1-receptor agonist, and nonsteroidal mineralocorticoid-receptor antagonist classes now are considered standard of care to improve kidney, heart, and overall survival outcomes in patients with type 2 diabetes. Efforts to educate health care providers on the benefits of these therapies are critically needed to help increase their utilization and improve clinical outcomes. Care decisions should be driven by a holistic view of patient priorities and goals with consideration of a multimodal therapeutic approach to maximize heart and kidney benefits.

Vaccinium as Potential Therapy for Diabetes and Microvascular Complications

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

Post hoc analysis of SUSTAIN 6 and PIONEER 6 trials suggests that people with type 2 diabetes at high cardiovascular risk treated with semaglutide experience more stable kidney function compared with placebo

Glucagon-like peptide-1 receptor agonists reduce albuminuria and may stabilize the estimated glomerular filtration rate (eGFR) in people with type 2 diabetes (T2D). In this post hoc analysis of the SUSTAIN 6/PIONEER 6 trials encompassing 6480 participants at high cardiovascular risk (semaglutide, 3239 participants; placebo, 3241 participants), we investigated the effects of semaglutide versus placebo on eGFR decline. Pooled data by treatment were evaluated for annual eGFR change (total annual eGFR slope in ml/min per 1.73 m2) from baseline to end of treatment and time to persistent eGFR reductions of 30%, 40%, 50% and 57% or more, including subgroup analyses by baseline eGFR (30 to under 60 or 60 and over ml/min per 1.73 m2). In the overall population, the estimated treatment difference (ETD; semaglutide versus placebo) in annual eGFR slope was significant at 0.59 ml/min per 1.73 m2 (95% confidence interval 0.29; 0.89). The ETD was numerically largest in the 30 to under 60 ml/min per 1.73 m2 eGFR subgroup, 1.06 ml/min per 1.73 m2 (0.45; 1.67), but no significant interaction was observed for treatment effect by subgroup. Hazard ratios (semaglutide versus placebo) for time to persistent eGFR decline were under 1.0 for all eGFR thresholds in the overall population; and were numerically lower in the baseline eGFR 30 to under 60 ml/min per 1.73 m2 subgroup versus the overall population, although no significant interaction was observed for treatment effect by subgroup. Thus, pooled analyses of clinical trial data in patients with T2D suggest that semaglutide may reduce the rate of eGFR decline.

Acute kidney injury in diabetes mellitus: Epidemiology, diagnostic, and therapeutic concepts

Acute kidney injury (AKI) and diabetes mellitus (DM) are public health problems that cause a high socioeconomic burden worldwide. In recent years, the landscape of AKI etiology has shifted: Emerging evidence has demonstrated that DM is an independent risk factor for the onset of AKI, while an alternative perspective considers AKI as a bona fide complication of DM. Therefore, it is necessary to systematically characterize the features of AKI in DM. In this review, we summarized the epidemiology of AKI in DM. While focusing on circulation- and tissue-specific microenvironment changes after DM, we described the active cellular and molecular mechanisms of increased kidney susceptibility to AKI under DM stress. We also reviewed the current diagnostic and therapeutic strategies for AKI in DM recommended in the clinic. Updated recognition of the epidemiology, pathophysiology, diagnosis, and medications of AKI in DM is believed to reveal a path to mitigate the frequency of AKI and DM comorbidity that will ultimately improve the quality of life in DM patients.

Urinary microRNA in Diabetic Kidney Disease: A Literature Review

Diabetic kidney disease is the most common primary disease of end-stage kidney disease globally; however, a sensitive and accurate biomarker to predict this disease remains awaited. microRNAs are endogenous single-stranded noncoding RNAs that have intervened in different post-transcriptional regulations of various cellular biological functions. Previous literatures have reported its potential role in the pathophysiology of diabetic kidney disease, including regulation of Transforming Growth Factor-β1-mediated fibrosis, extracellular matrix and cell adhesion proteins, cellular hypertrophy, growth factor, cytokine production, and redox system activation. Urinary microRNAs have emerged as a novel, non-invasive liquid biopsy for disease diagnosis. In this review, we describe the available experimental and clinical evidence of urinary microRNA in the context of diabetic kidney disease and discuss the future application of microRNA in routine practice.

Finerenone in patients across the spectrum of chronic kidney disease and type 2 diabetes by glucagon-like peptide-1 receptor agonist use

AIMS

To explore the modifying effect of glucagon-like peptide-1 receptor agonist (GLP-1RA) use on outcomes with finerenone across a wide spectrum of patients with chronic kidney disease (CKD) and type 2 diabetes (T2D) in the pooled analysis of FIDELIO-DKD and FIGARO-DKD.

MATERIALS AND METHODS

Patients with T2D and CKD treated with optimized renin-angiotensin system blockade were randomized to finerenone or placebo. Effects of finerenone on a cardiovascular composite outcome (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure) and a kidney composite outcome (kidney failure, sustained ≥57% estimated glomerular filtration rate [eGFR] decline, or renal death), change in urine albumin-to-creatinine ratio (UACR), and safety were analysed by GLP-1RA use.

RESULTS

Of 13 026 patients, 944 (7.2%) used GLP-1RAs at baseline. Finerenone reduced the risk of the cardiovascular composite outcome (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.52-1.11 with GLP-1RA; HR 0.87, 95% CI 0.79-0.96 without GLP-1RA; P-interaction = 0.63) and the kidney composite outcome (HR 0.82, 95% CI 0.45-1.48 with GLP-1RA; HR 0.77, 95% CI 0.67-0.89 without GLP-1RA; P-interaction = 0.79) irrespective of baseline GLP-1RA use. Reduction in UACR with finerenone at Month 4 was -38% in patients with baseline GLP-1RA use compared with -31% in those without GLP-1RA use (P-interaction = 0.03). Overall safety and incidence of hyperkalaemia were similar, irrespective of GLP-1RA use.

CONCLUSIONS

The cardiorenal benefits of finerenone on composite cardiovascular and kidney outcomes and UACR reduction in patients with CKD and T2D appear to be maintained, regardless of GLP-1RA use. Subsequent studies are needed to investigate any potential benefit of this combination.

Advance in the Correlation between Diabetic Nephropathy and Abnormal Serum Thyroid Hormone Levels in Patients

This study was developed to explore the correlation between diabetic nephropathy (DN) and abnormal serum thyroid hormone (TH) levels in patients, which can provide a reference for disease prevention and control in patients with DN. DN is the most serious complication of diabetes. The mortality rate of diabetic patients with DN is approximately 30 times higher than that of diabetic patients without DN. DN leads to high blood sugar, which causes vascular dysfunction in patients, causes cardiovascular disease, aggravates the disease and disease complexity, and thus increases the mortality of patients. DN patients often have oxidative stress and even fibrosis in severe cases. TH has a potential renal protective effect and can also regulate glucose metabolism and improve abnormal glucose tolerance and insulin resistance. Abnormal serum TH levels increase the risk of DN. Normal thyroid function plays an important role in regulating the physiological functions of the human body. Hormonal disorders promote the development of diabetes mellitus (DM) into DN. The pathogenesis, clinical manifestations, detection, and treatment methods of DN were reviewed in this study. The research progress of the influence of TH on DN was analyzed. This study is conducive to clinical research on DN and provides a reference.

Identification and validation of immune and oxidative stress-related diagnostic markers for diabetic nephropathy by WGCNA and machine learning

Background

Diabetic nephropathy (DN) is the primary cause of end-stage renal disease, but existing therapeutics are limited. Therefore, novel molecular pathways that contribute to DN therapy and diagnostics are urgently needed.

Methods

Based on the Gene Expression Omnibus (GEO) database and Limma R package, we identified differentially expressed genes of DN and downloaded oxidative stress-related genes based on the Genecard database. Then, immune and oxidative stress-related hub genes were screened by combined WGCNA, machine learning, and protein-protein interaction (PPI) networks and validated by external validation sets. We conducted ROC analysis to assess the diagnostic efficacy of hub genes. The correlation of hub genes with clinical characteristics was analyzed by the Nephroseq v5 database. To understand the cellular clustering of hub genes in DN, we performed single nucleus RNA sequencing through the KIT database.

Results

Ultimately, we screened three hub genes, namely CD36, ITGB2, and SLC1A3, which were all up-regulated. According to ROC analysis, all three demonstrated excellent diagnostic efficacy. Correlation analysis revealed that the expression of hub genes was significantly correlated with the deterioration of renal function, and the results of single nucleus RNA sequencing showed that hub genes were mainly clustered in endothelial cells and leukocyte clusters.

Conclusion

By combining three machine learning algorithms with WGCNA analysis, this research identified three hub genes that could serve as novel targets for the diagnosis and therapy of DN.

What's New in the Molecular Mechanisms of Diabetic Kidney Disease: Recent Advances

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease, including end-stage kidney disease, and increases the risk of cardiovascular mortality. Although the treatment options for DKD, including angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, sodium-glucose cotransporter 2 inhibitors, and mineralocorticoid receptor antagonists, have advanced, their efficacy is still limited. Thus, a deeper understanding of the molecular mechanisms of DKD onset and progression is necessary for the development of new and innovative treatments for DKD. The complex pathogenesis of DKD includes various different pathways, and the mechanisms of DKD can be broadly classified into inflammatory, fibrotic, metabolic, and hemodynamic factors. Here, we summarize the recent findings in basic research, focusing on each factor and recent advances in the treatment of DKD. Collective evidence from basic and clinical research studies is helpful for understanding the definitive mechanisms of DKD and their regulatory systems. Further comprehensive exploration is warranted to advance our knowledge of the pathogenesis of DKD and establish novel treatments and preventive strategies.

AICAR Improves Outcomes of Metabolic Syndrome and Type 2 Diabetes Induced by High-Fat Diet in C57Bl/6 Male Mice

The aim of the study was to investigate the effect of AMP-activated protein kinase activator 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on the consequences of metabolic syndrome and type 2 diabetes induced by the consumption of a high-fat diet (HFD) in male C57Bl/6 mice. Additionally, the animals from group 6 were administered Methotrexate (MTX) at a dose of 1 mg/kg in parallel with AICAR, which slows down the metabolism of AICAR. The animals were recorded with signs of metabolic syndrome and type 2 diabetes mellitus by recording their body weights, glucose and insulin levels, and the calculating HOMA-IRs. At the end of the study, at the end of the 13th week, during necropsy, the internal organs were assessed, the masses of the organs were recorded, and special attention was paid to visceral fat, assessing its amount and the mass of the fat surrounding epididymis. The biochemical parameters and histology of the internal organs and tissues were assessed. The animals showed signs of metabolic syndrome and type 2 diabetes, namely, weight gain, hyperglycemia, hyperinsulinemia, an increase in the amount and mass of abdominal fat, and metabolic disorders, all expressed in a pathological change in biochemical parameters and pathological changes in internal organs. The AICAR treatment led to a decrease in body weight, a decrease in the amount and mass of abdominal fat, and an improvement in the pathomorphological picture of internal organs. However, some hepatotoxic effects were observed when the animals, on a received standard diet (STD), were treated with AICAR starting from the first day of the study. The additional administration of MTX, an AICAR metabolic inhibitor, did not improve its efficacy. Thus, AICAR has therapeutic potential for the treatment of metabolic syndrome and type 2 diabetes.

Exenatide regulates Th17/Treg balance via PI3K/Akt/FoxO1 pathway in db/db mice

BACKGROUND

The T helper 17 (Th17)/T regulatory (Treg) cell imbalance is involved in the course of obesity and type 2 diabetes mellitus (T2DM). In the current study, the exact role of glucagon-like peptide-1 receptor agonist (GLP-1RA) exenatide on regulating the Th17/Treg balance and the underlying molecular mechanisms are investigated in obese diabetic mice model.

METHODS

Metabolic parameters were monitored in db/db mice treated with/without exenatide during 8-week study period. The frequencies of Th17 and Treg cells from peripheral blood and pancreas in db/db mice were assessed. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/Forkhead box O1 (FoxO1) pathway in Th17 and Treg cells from the spleens of male C57BL/6J mice was detected by western blotting. In addition, the expression of glucagon-like peptide-1 receptor (GLP-1R) in peripheral blood mononuclear cells (PBMCs) of male C57BL/6J mice was analyzed.

RESULTS

Exenatide treatment improved β-cell function and insulitis in addition to glucose, insulin sensitivity and weight. Increased Th17 and decreased Treg cells in peripheral blood were present as diabetes progressed while exenatide corrected this imbalance. Progressive IL-17 + T cell infiltration of pancreatic islets was alleviated by exenatide intervention. In vitro study showed no significant difference in the level of GLP-1R expression in PBMCs between control and palmitate (PA) groups. In addition, PA could promote Th17 but suppress Treg differentiation along with down-regulating the phosphorylation of PI3K/Akt/FoxO1, which was reversed by exenatide intervention. FoxO1 inhibitor AS1842856 could abrogate all these effects of exenatide against lipid stress.

CONCLUSIONS

Exenatide could restore systemic Th17/Treg balance via regulating FoxO1 pathway with the progression of diabetes in db/db mice. The protection of pancreatic β-cell function may be partially mediated by inhibiting Th17 cell infiltration into pancreatic islets, and the resultant alleviation of islet inflammation.

Emerging drugs for the treatment of diabetic nephropathy

INTRODUCTION

Diabetic nephropathy remains a significant economic and social burden on both the individual patient and health-care systems as the prevalence of diabetes increases in the general population. The complex pathophysiology of diabetic kidney disease poses a challenge in the development of effective medical treatments for the disease. However, the multiple facets of diabetic nephropathy also offer a variety of potential strategies to manage this condition.

AREAS COVERED

We retrieved PubMed, Cochrane Library, Scopus, Google Scholar, and ClinicalTrials.gov records to identify studies and articles focused on new pharmacologic advances to treat diabetic nephropathy.

EXPERT OPINION

RAAS blockers have remained the mainstay of therapy for DM nephropathy for many years, with only recent advancements with SGLT2 inhibitors and nonsteroidal MRAs. Better understanding of the long-term renal effects of ambient hyperglycemia, ranging from hemodynamic changes to increased production of oxidative and pro-inflammatory substances, has evolved our approach to the treatment of diabetic nephropathy. With continuing research for new therapeutics as well as combination therapy, the medical community may be able to better ease the burden of diabetic kidney disease.

Implications of cancer stem cells in diabetes and pancreatic cancer

This review provides a detailed study of pancreatic cancer (PC) and the implication of different types of cancers concerning diabetes. The combination of anti-diabetic drugs with other anti-cancer drugs and phytochemicals can help prevent and treat this disease. PC cancer stem cells (CSCs) and how they migrate and develop into malignant tumors are discussed. A detailed explanation of the different mechanisms of diabetes development, which can enhance the pancreatic CSCs' proliferation by increasing the IGF factor levels, epigenetic modifications, DNA damage, and the influence of lifestyle factors like obesity, and inflammation, has been discussed. It also explains how cancer due to diabetes is associated with high mortality rates. One of the well-known diabetic drugs, metformin, can be combined with other anti-cancer drugs and prevent the development of PC and has been taken as one of the prime focus in this review. Overall, this paper provides insight into the relationship between diabetes and PC and the methods that can be employed to diagnose this disease at an earlier stage successfully.

Discovering a trans-omics biomarker signature that predisposes high risk diabetic patients to diabetic kidney disease

Diabetic kidney disease is the leading cause of end-stage kidney disease worldwide; however, the integration of high-dimensional trans-omics data to predict this diabetic complication is rare. We develop artificial intelligence (AI)-assisted models using machine learning algorithms to identify a biomarker signature that predisposes high risk patients with diabetes mellitus (DM) to diabetic kidney disease based on clinical information, untargeted metabolomics, targeted lipidomics and genome-wide single nucleotide polymorphism (SNP) datasets. This involves 618 individuals who are split into training and testing cohorts of 557 and 61 subjects, respectively. Three models are developed. In model 1, the top 20 features selected by AI give an accuracy rate of 0.83 and an area under curve (AUC) of 0.89 when differentiating DM and non-DM individuals. In model 2, among DM patients, a biomarker signature of 10 AI-selected features gives an accuracy rate of 0.70 and an AUC of 0.76 when identifying subjects at high risk of renal impairment. In model 3, among non-DM patients, a biomarker signature of 25 AI-selected features gives an accuracy rate of 0.82 and an AUC of 0.76 when pinpointing subjects at high risk of chronic kidney disease. In addition, the performance of the three models is rigorously verified using an independent validation cohort. Intriguingly, analysis of the protein-protein interaction network of the genes containing the identified SNPs (RPTOR, CLPTM1L, ALDH1L1, LY6D, PCDH9, B3GNTL1, CDS1, ADCYAP and FAM53A) reveals that, at the molecular level, there seems to be interconnected factors that have an effect on the progression of renal impairment among DM patients. In conclusion, our findings reveal the potential of employing machine learning algorithms to augment traditional methods and our findings suggest what molecular mechanisms may underlie the complex interaction between DM and chronic kidney disease. Moreover, the development of our AI-assisted models will improve precision when diagnosing renal impairment in predisposed patients, both DM and non-DM. Finally, a large prospective cohort study is needed to validate the clinical utility and mechanistic implications of these biomarker signatures.

Effects of tirzepatide versus insulin glargine on kidney outcomes in type 2 diabetes in the SURPASS-4 trial: post-hoc analysis of an open-label, randomised, phase 3 trial

BACKGROUND

In the SURPASS-4 trial, the dual GIP and GLP-1 receptor agonist tirzepatide reduced HbA_1c concentrations, bodyweight, and blood pressure more than titrated daily insulin glargine in people with type 2 diabetes inadequately controlled on oral diabetes treatments and with high cardiovascular risk. We aimed to compare the effects of tirzepatide and insulin glargine on kidney parameters and outcomes in people with type 2 diabetes.

METHODS

We did a post-hoc analysis of data from SURPASS-4, a randomised, open-label, parallel-group, phase 3 study at 187 sites (including private practice, research institutes, and hospitals) in 14 countries. Eligible participants were adults (age ≥18 years), with type 2 diabetes treated with any combination of metformin, sulfonylurea, or SGLT2 inhibitor, and with baseline HbA_1c of 7·5-10·5% (58-91 mmol/mol), BMI of 25 kg/m² or greater, and established cardiovascular disease or a high risk of cardiovascular events. Randomisation via an interactive web-response system was 1:1:1:3 to a once-weekly subcutaneous injection of tirzepatide (5 mg, 10 mg, or 15 mg) or a once-daily subcutaneous injection of titrated insulin glargine (100 U/mL). The study included up to 104 weeks of treatment, with a median treatment duration of 85 weeks. We compared the rates of estimated glomerular filtration rate (eGFR) decline and the urine albumin-creatinine ratio (UACR) between the combined tirzepatide groups and the insulin glargine group in the modified intention-to-treat population. The kidney composite outcome was time to first occurrence of eGFR decline of at least 40% from baseline, end-stage kidney disease, death owing to kidney failure, or new-onset macroalbuminuria. This study is registered with ClinicalTrials.gov, NCT03730662.

FINDINGS

Between Nov 20, 2018, and Dec 30, 2019, we screened 3045 people, of whom 1043 (34%) were ineligible, and 2002 (66%) were randomly assigned to a study drug (997 to tirzepatide and 1005 to insulin glargine). 1995 (>99%) of 2002 received at least one dose of tirzepatide (n=995) or insulin glargine (n=1000). At baseline, participants had a mean eGFR of 81·3 (SD 21·11) mL/min per 1·73 m² and a median UACR of 15·0 mg/g (IQR 5·0-55·8). The mean rate of eGFR decline was -1·4 (SE 0·2) mL/min per 1·73 m² per year in the combined tirzepatide groups and -3·6 (0·2) mL/min per 1·73 m² per year in the insulin group (between-group difference 2·2 [95% CI 1·6 to 2·8]). Compared with insulin glargine, the reduction in the annual rate of eGFR decline induced by tirzepatide was more pronounced in participants with eGFR less than 60 mL/min per 1·73 m² than in those with eGFR 60 mL/min per 1·73 m² or higher (between-group difference 3·7 [95% CI 2·4 to 5·1]). UACR increased from baseline to follow-up with insulin glargine (36·9% [95% CI 26·0 to 48·7]) but not with tirzepatide (-6·8% [-14·1 to 1·1]; between-group difference -31·9% [-37·7 to -25·7]). Participants who received tirzepatide showed a significantly lower occurrence of the composite kidney endpoint compared with those who received insulin glargine (hazard ratio 0·58 [95% CI 0·43 to 0·80]).

INTERPRETATION

Our analysis suggests that in people with type 2 diabetes and high cardiovascular risk, tirzepatide slowed the rate of eGFR decline and reduced UACR in clinically meaningful ways compared with insulin glargine.

FUNDING

Eli Lilly and Company.

Nephroprotective Properties of the Glucose-Dependent Insulinotropic Polypeptide (GIP) and Glucagon-like Peptide-1 (GLP-1) Receptor Agonists

Diabetes mellitus is the leading cause of chronic kidney disease, and about 30–40% of patients with diabetes will develop kidney disease. Incretin hormones have received attention during the past three decades not only as a pharmacotherapy for the treatment of type 2 diabetes, but also for their cardiorenometabolic effects. The main incretins are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Additional to the pancreas, receptors for GLP-1 are widely distributed in various organs, causing positive effects on endothelial function and vascular atherogenesis. Along with glycemic control and weight reduction, GLP-1 receptor agonists also strongly improve cardiovascular and renal outcomes in patients with type 2 diabetes. Recently, a dual GIP and GLP-1 receptor agonist has been approved for the treatment of type 2 diabetes. Compared to GLP-1 receptor agonist semaglutide, dual GIP and GLP-1 receptor agonist tirzepatide showed a superior reduction in hemoglobin A1c and body weight. Preliminary results also suggest that tirzepatide improves kidney outcomes in adults with type 2 diabetes with increased cardiovascular risk. In this review, we present the nephroprotective properties of dual GIP and GLP-1 receptor agonists as a new drug to treat type 2 diabetes.