Impact of inflammation and anti-inflammatory modalities on diabetic cardiomyopathy healing: From fundamental research to therapy

The immunology of diabetic cardiomyopathy

Diabetic cardiomyopathy is a notable microvascular complication of diabetes, characterized primarily by myocardial fibrosis and functional abnormalities. Long-term hyperglycemia induces excessive activation and recruitment of immune cells and triggers the cascade of inflammatory responses, resulting in systemic and local cardiac inflammation. Emerging evidence highlights the significant roles of immunology in modulating the pathology of diabetic cardiomyopathy. As the primary effectors of inflammatory reactions, immune cells are consistently present in cardiac tissue and can be recruited under pathological hyperglycemia circumstances. A disproportionate favor to proinflammatory types of immune cells and the increased proinflammatory cytokine levels mediate fibroblast proliferation, phenotypic transformation, and collagen synthesis and ultimately rise to cardiac fibrosis and hypertrophy. Meanwhile, the severity of cardiac fibrosis is also strongly associated with the diverse phenotypes and phenotypic alterations of the immune cells, including macrophages, dendritic cells, mast cells, neutrophils, and natural killer cells in innate immunity and CD4+ T lymphocytes, CD8+ T lymphocytes, and B lymphocytes in adaptive immunity. In this review, we synthesized the current analysis of the critical role played by the immune system and its components in the progression of diabetic cardiomyopathy. Finally, we highlight preclinical and clinical immune targeting strategies and translational implications.

The role of IL-1 family cytokines in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is the primary cause of heart failure in patients with diabetes and is characterised by contractile dysfunction and left ventricular hypertrophy. The complex pathological and physiological mechanisms underlying DCM have contributed to a limited number of available treatment options. A substantial body of evidence has established that DCM is a low-grade inflammatory cardiovascular disorder, with the interleukin-1 (IL-1) family of cytokines playing crucial roles in initiating inflammatory responses and shaping innate and adaptive immunity. In this review, we aim to provide an overview of the underlying mechanisms of the IL-1 family and their relevance in DCM of various aetiologies. Furthermore, we highlighted potential therapeutic targets within the IL-1 family for the management of DCM.

Phloridzin prevents diabetic cardiomyopathy by reducing inflammation and oxidative stress

Oxidative stress and inflammation significantly contribute to the pathogenesis of diabetic cardiomyopathy (DCM). Persistent inflammatory stimuli drive the progression of myocardial fibrosis and impaired cardiac function. Phloridzin (Phl), a natural compound, demonstrates both anti-inflammatory and antioxidant properties. Nevertheless, its therapeutic potential and underlying mechanisms in DCM remain unclear. This study aimed to elucidate the mechanisms through which Phl inhibited myocardial fibrosis and exerted its antioxidative effects. The impact of Phl on DCM was evaluated using a high-fat/high-sugar diet combined with streptozotocin to induce an animal model and an in vitro H9C2 cell model stimulated by high glucose (HG). Untargeted metabolomics identified potential mechanisms underlying myocardial fibrosis. Phl treatment significantly enhanced left ventricular ejection fraction (EF%) and shortening fraction (FS%), while reducing myocardial injury markers, such as lactate dehydrogenase and creatine phosphokinase-MB, and suppressing myocardial collagen fiber accumulation. Simultaneously, Phl attenuated myocardial inflammation via inhibition of MyD88/NF-κB signaling, modulated the Nrf2/GPX4 axis to counter oxidative stress, and mitigated ferroptosis. In vitro, Phl inhibited high glucose-induced myocardial hypertrophy and fibrosis in H9C2 cells, while also repressing NF-κB activation in cardiomyocytes. Metabolomic profiling revealed that Phl ameliorated DCM through modulation of glycerophospholipid metabolic pathways, linking these metabolic shifts to enhanced antioxidant capacity, thereby reflecting its ability to reduce oxidative stress in the myocardium. Collectively, Phl provides cardioprotective effects by alleviating inflammation and oxidative damage.

Mechanistic insights and therapeutic potential of astilbin and apigenin in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) represents a critical complication of Diabetes mellitus (DM), characterized by structural and functional changes in the myocardium independent of coronary artery disease or hypertension. Emerging evidence highlights the significant roles of phytochemicals, particularly astilbin and apigenin, in modulating key molecular pathways implicated in DCM. This review synthesizes current mechanistic insights and therapeutic potential of these compounds, focusing on their interactions with AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptors (PPARs), O-linked N-acetylglucosamine (O-GlcNAc), sodium-glucose co-transporter 2 (SGLT2), protein kinase C (PKC), nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) pathways. Astilbin and apigenin have demonstrated the ability to improve cardiac function, mitigate oxidative stress, and reduce inflammatory responses in diabetic conditions. By activating AMPK and PPARs, these flavonoids enhance glucose uptake and fatty acid oxidation, contributing to improved metabolic homeostasis. Their inhibition of O-GlcNAcylation, SGLT2 activity, and PKC signaling further attenuates hyperglycemia-induced cellular damage. Additionally, suppression of NF-κB, MAPK, and JNK pathways by astilbin and apigenin results in reduced pro-inflammatory cytokine production and apoptotic cell death. Collectively, these interactions position astilbin and apigenin as promising therapeutic agents for ameliorating DCM, offering novel avenues for treatment strategies aimed at modulating multiple pathogenic pathways.

The mechanism and promising therapeutic strategy of diabetic cardiomyopathy dysfunctions: Focus on pyroptosis

Diabetes is a major risk factor for cardiovascular diseases, and myocardial damage caused by hyperglycemia is the main cause of heart failure. However, there is still a lack of systematic understanding of myocardial damage caused by diabetes. At present, we believe that the cellular inflammatory damage caused by hyperglycemia is one of the causes of diabetic cardiomyopathy. Pyroptosis, as a proinflammatory form of cell death, is closely related to the occurrence and development of diabetic cardiomyopathy. Therefore, this paper focuses on the important role of inflammation in the occurrence and development of diabetic cardiomyopathy. From the perspective of pyroptosis, we summarize the pyroptosis of different types of cells in diabetic cardiomyopathy and its related signaling pathways. It also summarizes the treatment of diabetic cardiomyopathy, hoping to provide methods for the prevention and treatment of diabetic cardiomyopathy by inhibiting pyroptosis.

Discovery of novel CXCR4 inhibitors for the treatment of inflammation by virtual screening and biological evaluation

C-X-C chemokine receptor type 4 (CXCR4) exerts considerable influence on the pathogenesis of inflammatory disorders and offers a potent avenue for drug intervention. This research utilizes a hybrid virtual screening methodology constructed using computer-aided drug design to discover novel CXCR4 inhibitors for the treatment of inflammation. First, a compound library was screened by Lipinski's five rules and adsorption, distribution, metabolism, excretion and toxicity properties. Second, the HypoGen algorithm was used in constructing a 3D-QSAR pharmacophore model and verify it layer by layer, and the obtained optimal pharmacophore 1 (Hypo 1) was used as a 3D query for compound screening. Then, hit compounds were obtained through molecular docking (Libdock and CDOCKER). The toxicity of the compounds to MDA-MB-231 cells was evaluated in vitro, and their binding affinity to the target was evaluated according to how they compete with 12G5 antibody for CXCR4 on the surfaces of the MDA-MB-231 cells. Compound Hit14 showed the strongest binding affinity among the hit compounds and inhibited cell migration and invasion in Matrigel invasion and wound healing assay at a concentration of 100 nM, demonstrating a better effect than AMD3100. Western Blot experiments further showed that Hit14 blocked the CXCR4/CXCL12-mediated phosphorylation of Akt. Meanwhile, cellular thermal displacement assay analysis showed that CXCR4 protein bound to Hit14 had high thermal stability. Finally, through in vivo experiments, we found that Hit14 inhibited mouse ear inflammation and reduced ear swelling and damage. Therefore, Hit14 is a promising drug for the further development of CXCR4 inhibitors for inflammation treatment.

Boldine prevents the inflammatory response of cardiac fibroblasts induced by SGK1-NFκB signaling pathway activation

Cardiac fibroblasts (CF) are mesenchymal-type cells responsible for maintaining the homeostasis of the heart's extracellular matrix (ECM). Their dysfunction leads to excessive secretion of ECM proteins, tissue stiffening, impaired nutrient and oxygen exchange, and electrical abnormalities in the heart. Additionally, CF act as sentinel cells in the cardiac tissue microenvironment, responding to various stimuli that may affect heart function. Deleterious stimuli induce an inflammatory response in CF, increasing the secretion of cytokines such as IL-1β and TNF-α and the expression of cell adhesion molecules like ICAM1 and VCAM1, initially promoting damage resolution by recruiting immune cells. However, constant harmful stimuli lead to a chronic inflammatory process and heart dysfunction. Therefore, it is necessary to study the mechanisms that govern CF inflammation. NFκB is a key regulator of the cardiac inflammatory process, making the search for mechanisms of NFκB regulation and CF inflammatory response crucial for developing new treatment options for cardiovascular diseases. SGK1, a serine-threonine protein kinase, is one of the regulators of NFκB and is involved in the fibrotic effects of angiotensin II and aldosterone, as well as in CF differentiation. However, its role in the CF inflammatory response is unknown. On the other hand, many bioactive natural products have demonstrated anti-inflammatory effects, but their role in CF inflammation is unknown. One such molecule is boldine, an alkaloid obtained from Boldo (Peumus boldus), a Chilean endemic tree with proven cytoprotective effects. However, its involvement in the regulation of SGK1 and CF inflammation is unknown. In this study, we evaluated the role of SGK1 and boldine in the inflammatory response in CF isolated from neonatal Sprague-Dawley rats. The involvement of SGK1 was analyzed using GSK650394, a specific SGK1 inhibitor. Our results demonstrate that SGK1 is crucial for LPS- and IFN-γ-induced inflammatory responses in CF (cytokine expression, cell adhesion molecule expression, and leukocyte adhesion). Furthermore, a conditioned medium (intracellular content of CF subject to freeze/thaw cycles) was used to simulate a sterile inflammation condition. The conditioned medium induced a potent inflammatory response in CF, which was completely prevented by the SGK1 inhibitor. Finally, our results indicate that boldine inhibits both SGK1 activation and the CF inflammatory response induced by LPS, IFN-γ, and CF-conditioned medium. Taken together, our results position SGK1 as an important regulator of the CF inflammatory response and boldine as a promising anti-inflammatory drug in the context of cardiovascular diseases.

Dihydromyricetin regulates RIPK3-CaMKII to prevent necroptosis in high glucose-stimulated cardiomyocytes

Background

Diabetic cardiomyopathy is one common cardiovascular complication without effective treatments. Dihydromyricetin (DHY), a natural dihydroflavonol compound extracted from Ampelopsis grossedentata, possesses versatile pharmacologically important effects. In our current research, we planned to evaluate the impact and probable DHY mechanisms in high glucose (HG)-induced cardiomyocytes.

Methods

Primary cardiomyocytes were pretreated with different concentrations of DHY (0, 20, 40, 80, 160, and 320 μM) for various time (0, 1, 2, 4, 12, and 24 h). They were then stimulated for 48 h with 5.5 mmol/L normal glucose (NG) and 33.3 mmol/L high glucose (HG). Cell viability, adenosine-triphosphate (ATP) levels, and lactate dehydrogenase (LDH) release of cardiomyocytes were detected. JC-1 staining was employed to measure the mitochondrial membrane potential. MitoSOX staining and dihydroethidium (DHE) staining were applied to evaluate the oxidative stress levels. TDT mediated dUTP nick end labeling (TUNEL) was used to measure apoptotic levels. Expressions of calcium/calmodulin-dependent protein kinase II (CaMKII), phospholamban (PLB), optic atrophy 1 (OPA1), dynamin-related protein 1 (DRP1), caspase 3, mixed kinase lineage domain like protein (MLKL), receptor interacting protein kinase 3 (RIPK3), and receptor interacting protein kinase 1 (RIPK1) were detected by immunofluorescence and/or Western blot.

Results

DHY improved cell viability, enhanced ATP level, and decreased LDH content in HG-stimulated cardiomyocytes, suggesting DHY attenuating cell injury. DHY reduced number of TUNEL positive cells, inhibited RIPK3 and cleaved-caspase 3 expression, implying DHY alleviated necroptosis in HG-stimulated cardiomyocytes. DHY diminished JC-1 monomers, DHE and MitoSOX fluorescence intensity as well as DRP1 expression but increased JC-1 aggregates intensity and OPA1 expression, indicating that DHY attenuated oxidative stress in HG-stimulated cardiomyocytes. DHY also attenuated CaMKII activity by suppressed PLB phosphorylation and inhibited CaMKII oxidation in HG-stimulated cardiomyocytes.

Conclusions

HG-induced cardiomyocytes injury was alleviated wherein DHY attenuated necroptosis, repressed ROS production, and inhibited CaMKII oxidation, suggesting that DHY may serve as potential agent to prevent and treat diabetic cardiomyopathy.

Meta-analysis on GLP-1 mediated modulation of autophagy in islet β-cells: Prospectus for improved wound healing in type 2 diabetes

Type 2 diabetes mellitus refers to a significantly challenging health disease due to its high prevalence and risk of other chronic diseases across the world. Notably, GLP-1 has been recognized to enhance the treatment of T2DM, along with this, GLP-1 is also involved in autophagy modulation. However, ineffectiveness of few analogue types can limit the efficacy of this treatment. This study particularly aims to elucidate the influence of GLP-1 receptor analogues on wound infection and patients with type 2 diabetes. To conduct the meta-analysis, an expansive literature survey was conducted to unveil the studies and research conducted on T2DM patients that revealed whether the adoption of any GLP-1 analogue in the form of specific interventions impacts the type 2 diabetes mellitus. The literature was searched using multiple search terms, screened and data were extracted to conduct the meta-analysis and it was conducted using metabin function of R package meta. A total of 800 patients consisting of the both intervention and control groups were employed to carry out the meta-analysis to analyse and evaluate the impact of GLP-1 mediated modulation to improve wound healing in the T2DM patients. The results revealed that GLP-1 mediated modulation considering one type of analogue was an effective intervention to patients suffering from T2DM. The variations in these results depicted insignificant outcomes with the values (risk ratio [RR]: 1.03, 95% confidence interval [CI]: 0.90-1.18, p > 0.05) and enlightened the fact that adopting different GLP-1 analogues may significantly improve the efficacy of wound healing in T2DM patients. Hence, interventions of GLP-1 mediated modulation must be utilized in the clinical practice to reduce the incidence of T2DM patients.