Diabetes and Cardiovascular Complications: The Epidemics Continue

Targeting SETD7 Rescues Diabetes-Induced Impairment of Angiogenic Response by Transcriptional Repression of Semaphorin-3G

Revascularization strategies failed to improve outcome in patients with diabetes with peripheral artery disease (PAD). Histone modifications are key modulators of gene expression and could play a role in angiogenic response. This study investigates the role of chromatin remodelling in modulating angiogenesis in diabetes. RNA sequencing (RNA-seq), and angiogenic assays (cell migration and tube formation) were performed in human aortic endothelial cells (HAECs) exposed to normal glucose (NG, 5 mmol/L) or high glucose (HG, 25 mmol/L) for 48 h. The expression of the histone methyltransferase SETD7 and its chromatin signature at histone 3 on lysine 4 (H3K4me1) were investigated by Western blot and chromatin immunoprecipitation (ChIP). Diabetic mice were treated with the SETD7 inhibitor (R)-PFI-2 or vehicle and underwent hind limb ischemia by femoral artery ligation. The experimental findings were translated into two cohorts of patients with diabetes with PAD. RNA-seq in HG-treated HAECs unveiled SETD7 as the top-ranking transcript. SETD7 upregulation was associated with increased H3K4me1 levels and defective angiogenesis. Both SETD7 depletion and (R)-PFI-2 rescued hyperglycemia-induced impairment of HAECs migration and tube formation, while SETD7 overexpression blunted the angiogenic response. RNA-seq and ChIP assays showed that SETD7-induced H3K4me1 enables the transcription of the angiogenesis inhibitor semaphorin-3G (SEMA3G) by increasing chromatin accessibility to peroxisome proliferator-activated receptor-γ. In diabetic mice with hind limb ischemia, (R)-PFI-2 improved limb perfusion by suppressing SEMA3G. The SETD7/SEMA3G axis was upregulated in patients with diabetes with PAD. Of note, (R)-PFI-2 restored angiogenic properties in endothelial cells collected from patients with diabetes. These findings show that SETD7 is a druggable epigenetic target in diabetic PAD.

ARTICLE HIGHLIGHTS

Hyperglycemia increases SETD7 expression and SETD7-dependent histone 3 on lysine 4, thus leading to an open chromatin and active transcription of the antiangiogenic gene semaphorin-3G (SEMA3G). Gene silencing and selective pharmacological inhibition of SETD7 by (R)-PFI-2 both blunt histone 3 on lysine 4 levels and SEMA3G transcription, thus rescuing hyperglycemia-induced impairment of angiogenic properties. The SETD7 inhibitor (R)-PFI-2 promotes neovascularization and restores limb perfusion in diabetic mice. SETD7/SEMA3G signaling was dysregulated in two different cohorts of patients with diabetes with peripheral arterial disease. Treatment with (R)-PFI-2 in endothelial cells collected from patients with diabetes restores angiogenic properties.

Traditional Chinese medicine in the prevention of diabetes mellitus and cardiovascular complications: mechanisms and therapeutic approaches

Diabetes mellitus (DM) is a chronic endocrine and metabolic disorder characterized by persistent hyperglycemia that poses serious threats to human health and quality of life. The morbidity, disability, and mortality rates of cardiovascular complications stemming from chronic hyperglycemia are primary factors affecting the lifespan of patients with diabetes. Currently, there is no cure for DM. Standard biomedical treatments mostly control the symptoms using insulin injections or oral hypoglycemic drugs. Although the effect of standard biomedical therapy is remarkable, its long-term use is prone to toxic side effects. Numerous studies have recently found that Traditional Chinese Medicine (TCM) has strong advantages in the prevention and treatment of DM and cardiovascular complications (DACC). The collection, processing, preparation and clinical use of TCM are guided by the theory of TCM and follow the "holistic concept." Multiple components, pathways, and targets form the basis for the use of TCM in treating multiple parts and organs of the body simultaneously. TCM is mainly derived from natural medicines and their processed products and has fewer side effects. TCM is clinically used as compound prescriptions, botanical drugs, and monomers. TCM, either independently or in combination with standard biomedical treatments, has shown unique therapeutic advantages. This review aimed to explore the recently reported mechanisms of action of TCM in the prevention and treatment of DACC. These findings will aid the optimization of the current therapy or formation of a therapeutic schedule for integrated TCM and standard biomedical treatments.

Global, regional, and national burden of chronic kidney disease due to diabetes mellitus type 2 from 1990 to 2021, with projections to 2036: a systematic analysis for the Global Burden of Disease Study 2021

Background

Chronic kidney disease (CKD) due to type 2 diabetes mellitus (T2DM) has emerged as a significant global health burden, with rising incidence and prevalence rates observed over the past decades.

Methods

We utilized the latest data from the Global Burden of Disease Study (GBD) 2021. Firstly, we reported the number of incidence, prevalence, deaths, and Disability-Adjusted Life Years (DALYs) attributed to CKD due to T2DM, accompanied by their respective Age-Standardized Rates (ASRs), for the year 2021. This analysis encompassed a global perspective and was further stratified by various subtypes. Moreover, we examined trends globally and within specified sub-types to investigate the temporal dynamics of the ASRs. We estimated the percentage change in ASRs, providing a quantitative measure of the rate of change in the burden over the study period. Moreover, we utilized the Bayesian age-period-cohort (BAPC) model to forecast the future burden.

Results

Globally, the ASRs of CKD due to T2DM all have witnessed a notable rise except for age-standardized prevalence rate (ASPR). The trends observed in both sexes and nearly all age groups were found to be congruent with those of the overall population. The increase in disease burden being greatest in the middle and lower SDI regions. The predicted results showed that the ASRs would still increase from 2022 to 2036.

Conclusion

This study highlights the critical importance of addressing the growing burden of T2DM-related CKD on global health. Effective prevention and management strategies, including improvements in diabetes care, renal health promotion, and access to healthcare services, are urgently needed to mitigate the future impact of T2DM-related CKD.

miR-205-5p Modulates High Glucose-Induced VEGFA Levels in Diabetic Mice and ARPE-19 Cells

High glucose levels may cause vascular alterations in patients with diabetes, which can lead to complications such as diabetic retinopathy-an abnormal growth of retinal blood vessels. The micro-RNA miR-205-5p is known to regulate angiogenesis by modulating the expression of the vascular endothelial growth factor (VEGFA) in different systems. This study investigates the role of miR-205-5p in controlling VEGFA expression both in vitro and in the eye under hyperglycemic conditions. An alloxan-induced diabetic mouse model and retinal pigment epithelium human cell line (ARPE-19) were exposed to high glucose and treated with an ectopic miR-205-5p mimic. VEGFA mRNA and protein levels were assessed using qRT-PCR, Western blot, and immunocytochemistry. Additionally, human umbilical vein endothelial cells (HUVECs) were employed to evaluate angiogenesis. Our results show that high glucose significantly reduced miR-205-5p levels while upregulating VEGFA expression in both ARPE-19 cells and diabetic mice. The ectopic administration of miR-205-5p (via transfection or intravitreal injection) restored VEGFA levels and inhibited angiogenesis in HUVEC cultures. Based on these preliminary data, we suggest a potential therapeutic strategy against VEGFA involving miR-205-5p in proliferative eye-related vascular disorders.

Hyperglycemia amplifies TLR-mediated inflammatory response of M(IL4) macrophages to dyslipidemic ligands

Hyperglycemia is critical for initiation of diabetic vascular complications. We systemically addressed the role of hyperglycemia in the regulation of TLRs in primary human macrophages. Expression of TLRs (1-9) was examined in monocyte-derived M(NC), M(IFNγ), and M(IL4) differentiated in normoglycemic and hyperglycemic conditions. Hyperglycemia increased expression of TLR1 and TLR8 in M(NC), TLR2 and TLR6 in M(IFNγ), and TLR4 and TLR5 in M(IL4). The strongest effect of hyperglycemia in M(IL4) was the upregulation of the TLR4 gene and protein expression. Hyperglycemia amplified TLR4-mediated response of M(IL4) to lipopolysaccharide by significantly enhancing IL1β and modestly suppressing IL10 production. In M(IL4), hyperglycemia in combination with synthetic triacylated lipopeptide (TLR1/TLR2 ligand) amplified expression of TLR4 and production of IL1β. In summary, hyperglycemia enhanced the inflammatory potential of homeostatic, inflammatory, and healing macrophages by increasing specific profiles of TLRs. In combination with dyslipidemic ligands, hyperglycemia can stimulate a low-grade inflammatory program in healing macrophages supporting vascular diabetic complications.

SGLT-2 Inhibitors: The Next-generation Treatment for Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) has become a worldwide concern in recent years, primarily in highly developed Western societies. T2DM causes systemic complications, such as atherosclerotic heart disease, ischemic stroke, peripheral artery disease, kidney failure, and diabetes-related maculopathy and retinopathy. The growing number of T2DM patients and the treatment of long-term T2DM-related complications pressurize and exhaust public healthcare systems. As a result, strategies for combating T2DM and developing novel drugs are critical global public health requirements. Aside from preventive measures, which are still the most effective way to prevent T2DM, novel and highly effective therapies are emerging. In the spotlight of next-generation T2DM treatment, sodium-glucose co-transporter 2 (SGLT-2) inhibitors are promoted as the most efficient perspective therapy. SGLT-2 inhibitors (SGLT2i) include phlorizin derivatives, such as canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin. SGLT-2, along with SGLT-1, is a member of the SGLT family of proteins that play a role in glucose absorption via active transport mediated by Na+/K+ ATPase. SGLT-2 is only found in the kidney, specifically the proximal tubule, and is responsible for more than 90% glucose absorption. Inhibition of SGLT-2 reduces glucose absorption, and consequently increases urinary glucose excretion, decreasing blood glucose levels. Thus, the inhibition of SGLT-2 activity ultimately alleviates T2DM-related symptoms and prevents or delays systemic T2DM-associated chronic complications. This review aimed to provide a more detailed understanding of the effects of SGLT2i responsible for the acute improvement in blood glucose regulation, a prerequisite for T2DM-associated cardiovascular complications control.

RAGE/DIAPH1 and atherosclerosis through an evolving lens: Viewing the cell from the "Inside - Out"

BACKGROUND AND AIMS

In hyperglycemia, inflammation, oxidative stress and aging, Damage Associated Molecular Patterns (DAMPs) accumulate in conditions such as atherosclerosis. Binding of DAMPs to receptors such as the receptor for advanced glycation end products (RAGE) activates signal transduction cascades that contribute to cellular stress. The cytoplasmic domain (tail) of RAGE (ctRAGE) binds to the formin Diaphanous1 (DIAPH1), which is important for RAGE signaling. This Review will detail the evidence linking the RAGE/DIAPH1 signaling pathway to atherosclerosis and envisages future therapeutic opportunities from the "inside-out" point of view in affected cells.

METHODS

PubMed was searched using a variety of search terms, including "receptor for advanced glycation end products" along with various combinations including "and atherosclerosis," "soluble RAGE and atherosclerosis," "statins and RAGE," "PPAR and RAGE" and "SGLT2 inhibitor and RAGE."

RESULTS

In non-diabetic and diabetic mice, antagonism or global deletion of Ager (the gene encoding RAGE) retards progression and accelerates regression of atherosclerosis. Global deletion of Diaph1 in mice devoid of the low density lipoprotein receptor (Ldlr) significantly attenuates atherosclerosis; mice devoid of both Diaph1 and Ldlr display significantly lower plasma and liver concentrations of cholesterol and triglyceride compared to mice devoid of Ldlr. Associations between RAGE pathway and human atherosclerosis have been identified based on relationships between plasma/serum concentrations of RAGE ligands, soluble RAGEs and atherosclerosis.

CONCLUSIONS

Efforts to target RAGE/DIAPH1 signaling through a small molecule antagonist therapeutic strategy hold promise to quell accelerated atherosclerosis in diabetes and in other forms of cardiovascular disease.

Old and Novel Predictors for Cardiovascular Risk in Diabetic Foot Syndrome—A Narrative Review

Diabetic foot syndrome (DFS) is a complication associated with diabetes that has a strong negative impact, both medically and socio-economically. Recent epidemiological data show that one in six patients with diabetes will develop an ulcer in their lifetime. Vascular complications associated with diabetic foot have multiple prognostic implications in addition to limiting functional status and leading to decreased quality of life for these patients. We searched the electronic databases of PubMed, MEDLINE and EMBASE for studies that evaluated the role of DFS as a cardiovascular risk factor through the pathophysiological mechanisms involved, in particular the inflammatory ones and the associated metabolic changes. In the era of evidence-based medicine, the management of these cases in multidisciplinary teams of “cardio-diabetologists” prevents the occurrence of long-term disabling complications and has prognostic value for cardiovascular morbidity and mortality among diabetic patients. Identifying artificial-intelligence-based cardiovascular risk prediction models or conducting extensive clinical trials on gene therapy or potential therapeutic targets promoted by in vitro studies represent future research directions with a modulating role on the risk of morbidity and mortality in patients with DFS.

Homocysteine-targeting compounds as a new treatment strategy for diabetic wounds via inhibition of the histone methyltransferase SET7/9

In hypoxia and hyperglycemia, SET7/9 plays an important role in controlling HIF-1α methylation and regulating the transcription of HIF-1α target genes, which are responsible for angiogenesis and wound healing. Here, we report the Ir(III) complex Set7_1a bearing acetonitrile (ACN) ligands as a SET7/9 methyltransferase inhibitor and HIF-1α stabilizer. Interestingly, Set7_1a could engage SET7/9 and strongly inhibit SET7/9 activity, especially after preincubation with homocysteine (Hcy), which is elevated in diabetes. We hypothesize that Set7_1a exchanges ACN subunits for Hcy to disrupt the interaction between SET7/9 and SAM/SAH, which are structurally related to Hcy. Inhibition of SET7/9 methyltransferase activity by Set7_1a led to reduced HIF-1α methylation at the lysine 32 residue, causing increased HIF-1α level and recruitment of HIF-1α target genes that promote angiogenesis, such as VEGF, GLUT1, and EPO, in hypoxia and hyperglycemia. Significantly, Set7_1a improved wound healing in a type 2 diabetic mouse model by activating HIF-1α signaling and downstream proangiogenic factors. To our knowledge, this is the first Hcy-targeting iridium compound shown to be a SET7/9 antagonist that can accelerate diabetic wound healing. More importantly, this study opens a therapeutic avenue for the treatment of diabetic wounds by the inhibition of SET7/9 lysine methyltransferase activity.

Animal trials have demonstrated the potential of a new drug strategy to heal the wounds associated with diabetes, especially in the feet,which often lead to chronic damage, sometimes treatable only by amputation. Leung CH and Lin L at the University of Macau, China, and Ma DL at the Hong Kong Baptist University tested the new therapy on a mouse model of type 2 diabetes. The treatment uses a homocysteine-targeting metal complex that inhibits a key enzyme SET7/9 involved in the processes that cause diabetic wounds. The treatment activated a molecular signalling cascade involved in generating the new blood vessels needed for wounds to heal. It could help address the urgent need for better treatments for this serious problem.

Targeting calcium-mediated inter-organellar crosstalk in cardiac diseases

INTRODUCTION

Abnormal calcium signaling between organelles such as the sarcoplasmic reticulum (SR), mitochondria and lysosomes is a key feature of heart diseases. Calcium serves as a secondary messenger mediating inter-organellar crosstalk, essential for maintaining the cardiomyocyte function.

AREAS COVERED

This article examines the available literature related to calcium channels and transporters involved in inter-organellar calcium signaling. The SR calcium-release channels ryanodine receptor type-2 (RyR2) and inositol 1,4,5-trisphosphate receptor (IP3R), and calcium-transporter SR/ER-ATPase 2a (SERCA2a) are illuminated. The roles of mitochondrial voltage-dependent anion channels (VDAC), the mitochondria Ca2+ uniporter complex (MCUC), and the lysosomal H+/Ca2+ exchanger, two pore channels (TPC), and transient receptor potential mucolipin (TRPML) are discussed. Furthermore, recent studies showing calcium-mediated crosstalk between the SR, mitochondria, and lysosomes as well as how this crosstalk is dysregulated in cardiac diseases are placed under the spotlight.

EXPERT OPINION

Enhanced SR calcium release via RyR2 and reduced SR reuptake via SERCA2a, increased VDAC and MCUC-mediated calcium uptake into mitochondria, and enhanced lysosomal calcium-release via lysosomal TPC and TRPML may all contribute to aberrant calcium homeostasis causing heart disease. While mechanisms of this crosstalk need to be studied further, interventions targeting these calcium channels or combinations thereof might represent a promising therapeutic strategy.