Emerging markers of inflammation and oxidative stress as potential predictors of coronary artery disease

Comprehensive analysis of single-cell and bulk transcriptome unravels immune landscape of atherosclerosis and develops a S100 family based-diagnostic model

BACKGROUND

The S100 family of calcium-binding proteins (S100s) had been tightly related to the biological processes of various cardiovascular diseases. This study aims to investigate the expression of S100s in Atherosclerosis (AS) and explore their potential as diagnostic biomarkers and therapeutic targets.

METHODS

We analyzed multiple sequencing datasets from the GEO database to compare the expression profiles of S100s in AS tissues versus normal samples. Employing unsupervised clustering techniques, AS subtypes were discerned based on the intricate variations in S100-related gene expression profiles. Subsequent analyses delved into immune cell infiltration and GSVA pathway enrichment, shedding light on the nuanced immune landscape characterizing diverse AS subtypes. Machine learning techniques were employed to develop a diagnostic model for AS. Single-cell RNA analysis was utilized to investigate the cellular distribution of S100 hub genes in AS.

RESULTS

Unsupervised clustering analysis identified two distinct AS subtypes (C1 and C2), characterized by specific S100 gene expression patterns. The RF-based diagnostic model exhibited the highest efficacy (AUC=0.881), and the top five genes (S100A4, S100A10, S100A11, S100A13, S100Z) were used to construct a diagnostic nomogram.

CONCLUSION

This study systematically elucidates the roles of S100s in AS, offering insights into molecular subtyping, immune characteristics, and diagnostic model construction. The findings provide valuable implications for the precise treatment and prognosis assessment of AS and pave the way for further research into related mechanisms.

Analysis of serum S100A12, soluble advanced glycation end products receptor, and gut microbiome in elderly patients with colorectal cancer

BACKGROUND

Colorectal cancer (CRC) ranks among the most prevalent malignancies in elderly populations, and chemotherapy resistance remains a critical clinical challenge. Emerging evidence highlights the interplay between chronic inflammation, gut microbiome dysbiosis, and CRC progression. Proinflammatory cytokines [e.g., interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α)] and mediators like S100 calcium-binding protein A12 (S100A12)/soluble receptor for advanced glycation end products (sRAGE) are implicated in tumorigenesis, while gut microbial imbalances may exacerbate inflammatory microenvironments conducive to chemotherapy resistance. However, the triad relationship between S100A12/sRAGE, gut microbiota profiles, and chemotherapy efficacy in elderly patients with CRC remains unexplored, limiting biomarker-driven therapeutic strategies.

AIM

To analyze the correlation between serum levels of S100A12, sRAGE, gut microbiome dysbiosis, and systemic inflammation in elderly patients with CRC and to assess their predictive value for chemotherapy efficacy.

METHODS

A retrospective analysis was conducted on the clinical data of 120 elderly patients with advanced-stage CRC who visited our hospital from August 2023 to May 2024. These patients were enrolled in the study group. Additionally, 120 healthy individuals undergoing routine health check-ups during the same period were selected as the control group. Serum S100A12, sRAGE, IL-6, and TNF-α levels were measured by ELISA, and fresh stool samples were collected before chemotherapy to analyze gut microbiome composition in the study group. Follow-up observations were conducted after chemotherapy. Pearson correlation analysis was used to explore the relationship between serum S100A12, sRAGE levels, and gut microbiome dysbiosis in patients with CRC. The predictive diagnostic value of pre-chemotherapy serum S100A12 and sRAGE levels for chemotherapy efficacy was assessed using receiver operating characteristic curves.

RESULTS

Pre-chemotherapy serum S100A12, sRAGE, IL-6, and TNF-α levels were significantly elevated in patients with CRC vs controls (all P < 0.05). These biomarkers progressively increased with microbiota dysbiosis severity (severe vs mild dysbiosis: S100A12: 340.26 ± 52.39 μg/L vs 302.53 ± 56.97 μg/L; sRAGE: 525.64 ± 37.32 ng/L vs 441.38 ± 48.73 ng/L, P < 0.05) and correlated strongly with IL-6 (r = 0.712) and TNF-α (r = 0.698). Post-chemotherapy, biomarker levels decreased (P < 0.05), coinciding with beneficial microbiota recovery (Bifidobacterium 176%, Lactobacillus 153%) and pathogenic taxa reduction (Escherichia coli 62%). The combined S100A12/sRAGE model predicted chemotherapy resistance with an area under the curve of 0.914 (sensitivity = 86.07%, specificity = 88.89%), outperforming individual biomarkers.

CONCLUSION

Elevated serum S100A12 and sRAGE in elderly patients with CRC reflected gut microbiome dysbiosis and systemic inflammation, driven by IL-6/TNF-α signaling. Their post-chemotherapy decline parallels microbiota restoration, supporting a microbiome-inflammation-biomarker axis. The combined biomarker model offers robust clinical utility for chemotherapy efficacy prediction and personalized therapeutic strategies.

Diagnostic biomarkers and immune infiltration profiles common to COVID-19, acute myocardial infarction and acute ischaemic stroke using bioinformatics methods and machine learning

BACKGROUND

COVID-19 is a disease that affects people globally. Beyond affecting the respiratory system, COVID-19 patients are at an elevated risk for both venous and arterial thrombosis. This heightened risk contributes to an increased probability of acute complications, including acute myocardial infarction (AMI) and acute ischemic stroke (AIS). Given the unclear relationship between COVID-19, AMI, and AIS, it is crucial to gain a deeper understanding of their associations and potential molecular mechanisms. This study aims to utilize bioinformatics to analyze gene expression data, identify potential therapeutic targets and biomarkers, and explore the role of immune cells in the disease.

METHODS

This study employed three Gene Expression Omnibus (GEO) datasets for analysis, which included data on COVID-19, AMI and AIS. We performed enrichment analysis on the co-DEGs for these three diseases to clarify gene pathways and functions, and also examined the relationship between co-DEGs and immune infiltration. Machine learning techniques and protein-protein interaction networks (PPI) were used to identify hub genes within the co-DEGs. Finally, we employed a dual validation strategy integrating independent GEO datasets and in vitro experiments with human blood samples to comprehensively assess the reliability of our experimental findings.

RESULTS

We identified 88 co-DEGs associated with COVID-19, AMI and AIS. Enrichment analysis results indicated that co-DEGs were significantly enriched in immune inflammatory responses related to leukocytes and neutrophils. Immune infiltration analysis revealed significant differences in immune cell populations between the disease group and the normal group. Finally, genes selected through machine learning methods included: CLEC4E, S100A12, and IL1R2. Based on the PPI network, the top ten most influential DEGs were identified as MMP9, TLR2, TLR4, ITGAM, S100A12, FCGR1A, CD163, FCER1G, FPR2, and CLEC4D. The integration of the protein-protein interaction (PPI) network with machine learning techniques facilitated the identification of S100A12 as a potential common biomarker for early diagnosis and a therapeutic target for all three diseases. Ultimately, validation of S100A12 showed that it was consistent with our experimental results, confirming its reliability as a biomarker. Moreover, it demonstrated good diagnostic performance for the three diseases.

CONCLUSION

We employed bioinformatics methods and machine learning to investigate common diagnostic biomarkers and immune infiltration characteristics of COVID-19, AMI and AIS. Functional and pathway analyses indicated that the co-DEGs were primarily enriched in immune inflammatory responses related to leukocytes and neutrophils. Through two machine learning approaches and the PPI network, and subsequent validation and evaluation, we identified S100A12 as a potential common therapeutic target and biomarker related to immune response that may influence these three diseases.

Association between S100A12 and risk of peripheral arterial disease in patients with dyslipidemia: a cross-sectional study

OBJECTIVE

S100A12 acts as a pro-inflammatory agent in vivo, with a close relationship with plaque formation in patients with acute coronary syndrome (ACS), end-stage renal disease, and diabetes. Peripheral arterial disease (PAD) can lead to mobility difficulties and ultimately disability and amputation. The association between S100A12 and risk of peripheral arterial disease remains unclear. This study aims to investigate the association between S100A12 and the risk of PAD in patients with dyslipidemia.

METHODS

From March 2023 to June 2024, 478 patients were included in this cross-sectional study. They were divided into PAD group (n = 105) and control group (n = 373) according to the presence or absence of PAD (The diagnosis of PAD is a combination of the patient's clinical symptoms, imaging evidence and ankle-brachial index). Plasma S100A12 was detected by available kit. General information, disease history, smoking history, and laboratory indicators were collected from both groups. The relationship between S100A12 and the risk of PAD was analyzed using statistical methods.

RESULTS

Levels of S100A12 were significantly higher in the PAD group of dyslipidemia [0.22 (0.13,1.49) ng/cL vs. 0.13 (0.10,0.18)ng/cL, p value < 0.001]. Univariate and multivariate logistic regression analyses suggested that the risk of PAD was significantly higher with increasing levels of S100A12 [Odd ratio (OR) (95%CI) = 2.264 (1.681, 3.047), p value < 0.05]. In addition, lower high-density lipoprotein cholesterol (HDL-C) level and diabetes mellitus (DM) were independent risk factors for PAD [OR (95%CI) = 0.388 (0.186,0.809), p value = 0.012; OR = 2.375 (1.527,3.695), p value < 0.001]. Subgroup analysis suggested that S100A12 was significantly and positively associated with the risk of PAD in all subgroups, regardless of whether HDL-C levels < 1.03 mmol/L, age > 60 years, and presence of diabetes or hypertension. Restricted cubic spline (RCS) curves suggested that the correlation between S100A12 and the risk of PAD was nonlinear (p-non-linear value < 0.05). The RCS curves showed that the positive correlation between S100A12 and the risk of PAD was stronger when the S100A12 level was less than 1.00ng/cL.

CONCLUSION

In conclusion, elevated S100A12 level is an independent risk factor for PAD in patients with dyslipidemia. In different subgroups, S100A12 was significantly and positively associated with the risk of PAD after adjusting for different factors. There is a non-linear relationship between S100A12 and the risk of PAD, with a stronger positive correlation at S100A12 levels below 1.00ng/cL. These findings implied that S100A12 is a potential biomarker for identifying patients with dyslipidemia who are at high risk of developing PAD. They also implied that S100A12 levels can be routinely monitored in dyslipidemic populations for the early detection of PAD and to guide the management of PAD. Finally, the results of this study emphasize that inflammation in dyslipidemia patients plays an important role in the development of PAD, suggesting that lipid control and immunomodulation may be effective in the prevention of PAD.

CLINICAL TRIAL NUMBER

MR-35-24-038431.

Preliminary insights into the effects of spinal manipulation therapy of different force magnitudes on blood biomarkers of oxidative stress and pro-resolution of inflammation mediators

BACKGROUND

Evidence has been reported that spinal manipulation therapy (SMT) leads to spine segmental hypoalgesia through neurophysiological and peripheral mechanisms related to regulating inflammatory biomarker function. However, these studies also showed substantial inter-individual variability in the biomarker responses. Such variability may be due to the incomplete understanding of the fundamental effects of force-based manipulations (e.g., patient-specific force-time characteristics) on a person's physiology in health and disease. This study investigated the short-term effects of distinct SMT force-time characteristics on blood oxidative stress and pro-resolution of inflammation biomarkers.

METHODS

Nineteen healthy adults between 18 and 45 years old were recruited between February and March 2020 before the COVID-19 pandemic and clustered into three groups: control (preload only), target total peak force of 400 N, and 800 N. A validated force-sensing table technology (FSTT®) determined the SMT force-time characteristics. Blood samples were collected at pre-intervention, immediately after SMT, and 20 min post-intervention. Parameters of the oxidant system (total oxidant status, lipid peroxidation and lipid hydroperoxide), the antioxidant system (total antioxidant capacity and bilirubin), and lipid-derived resolvin D1 were evaluated in plasma and erythrocytes through enzyme-linked immunosorbent assay and colorimetric assays.

RESULTS

The COVID-19 global pandemic impacted recruitment, and our pre-established target sample size could not be reached. As a result, there was a small sample size, which decreased the robustness of the statistical analysis. Despite the limitations, we observed that 400 N seemed to decrease systemic total oxidant status and lipid peroxidation biomarkers. However, 800 N appeared to transitorily increase these pro-oxidant parameters with a further transitory reduction in plasma total antioxidant capacity and resolvin D1 mediator.

CONCLUSION

Despite the small sample size, which elevates the risk of type II error (false negatives), and the interruption of recruitment caused by the pandemic, our findings appeared to indicate that different single SMT force-time characteristics presented contrasting effects on the systemic redox signalling biomarkers and pro-resolution of inflammation mediators in healthy participants. The findings need to be confirmed by further research; however, they provide baseline information and guidance for future studies in a clinical population.

Predictive Value of Selected Plasma Biomarkers in the Assessment of the Occurrence and Severity of Coronary Artery Disease

Despite significant advances in imaging modalities for diagnosing coronary artery disease (CAD), there remains a need for novel diagnostic approaches with high predictive values and fewer limitations. Circulating biomarkers, including cytokines such as interleukin-6 (IL-6) and interleukin-8 (IL-8), cell adhesion molecules such as soluble vascular cell adhesion molecule-1 (sVCAM-1), peptides secreted by endothelial cells such as endothelin-1 (ET-1), and enzymes involved in extracellular matrix remodeling such as a disintegrin and metalloproteinase with thrombospondin motifs-1 (ADAMTS-1) offer a promising alternative. This study aimed to evaluate the correlation between the plasma levels of selected biomarkers and the presence and severity of CAD. We enrolled 40 patients admitted for elective coronary angiography. CAD was defined as having at least one coronary artery stenosis ≥ 50%. The severity of CAD was assessed using the Gensini Score (GS). IL-8 levels were significantly higher in the CAD group, with a mean of 9.78 (SD 0.46) compared to 8.37 (SD 0.40) in the non-CAD group (p = 0.0228). No significant differences were observed for the other biomarkers between the groups. A positive Spearman correlation was found between IL-8 levels and the GS (ρ = 0.39, p = 0.017). These findings suggest that IL-8 may have potential as an additional tool for diagnosing or excluding atherosclerosis. Further studies with larger sample sizes are needed to validate its clinical utility.

Glycolipid Metabolic Disorders, Metainflammation, Oxidative Stress, and Cardiovascular Diseases: Unraveling Pathways

Glycolipid metabolic disorders (GLMDs) are various metabolic disorders resulting from dysregulation in glycolipid levels, consequently leading to an increased risk of obesity, diabetes, liver dysfunction, neuromuscular complications, and cardiorenal vascular diseases (CRVDs). In patients with GLMDs, excess caloric intake and a lack of physical activity may contribute to oxidative stress (OxS) and systemic inflammation. This study aimed to review the connection between GLMD, OxS, metainflammation, and the onset of CRVD. GLMD is due to various metabolic disorders causing dysfunction in the synthesis, breakdown, and absorption of glucose and lipids in the body, resulting in excessive ectopic accumulation of these molecules. This is mainly due to neuroendocrine dysregulation, insulin resistance, OxS, and metainflammation. In GLMD, many inflammatory markers and defense cells play a vital role in related tissues and organs, such as blood vessels, pancreatic islets, the liver, muscle, the kidneys, and adipocytes, promoting inflammatory lesions that affect various interconnected organs through their signaling pathways. Advanced glycation end products, ATP-binding cassette transporter 1, Glucagon-like peptide-1, Toll-like receptor-4, and sphingosine-1-phosphate (S1P) play a crucial role in GLMD since they are related to glucolipid metabolism. The consequences of this is system organ damage and increased morbidity and mortality.

Tailored quinoline hybrids as promising COX-2/15-LOX dual inhibitors endowed with diverse safety profile: Design, synthesis, SAR, and histopathological study

Complications of the worldwide use of non-steroidal anti-inflammatory drugs (NSAIDs) sparked scientists to design novel harmless alternatives as an urgent need. So, a unique hybridization tactic of quinoline/pyrazole/thioamide (4a-c) has been rationalized and synthesized as potential COX-2/15-LOX dual inhibitors, utilizing relevant reported studies on these pharmacophores. Moreover, we extended these preceding hybrids into more varied functionality, bearing crucial thiazole scaffolds(5a-l). All the synthesized hybrids were evaluatedin vitroas COX-2/15-LOX dual inhibitors. Initially, series4a-cexhibited significant potency towards 15-LOX inhibition (IC50 = 5.454-4.509 μM) compared to meclofenamate sodium (IC50 = 3.837 μM). Moreover, they revealed reasonable inhibitory activities against the COX-2 enzyme in comparison to celecoxib.Otherwise, conjugates 5a-ldisclosed marked inhibitory activity against 15-LOX and strong inhibitory to COX-2. In particular, hybrids5d(IC50 = 0.239 μM, SI = 8.95), 5h(IC50 = 0.234 μM, SI = 20.35) and 5l (IC50 = 0.201 μM, SI = 14.42) revealed more potency and selectivity outperforming celecoxib (IC50 = 0.512 μM, SI = 4.28). In addition, the most potentcompounds, 4a, 5d, 5h, and 5l have been elected for further in vivoevaluation and displayed potent inhibition of edema in the carrageenan-induced rat paw edema test that surpassed indomethacin. Further, compounds5d, 5h, and 5l decreased serum inflammatory markers including oxidative biomarkersiNO, and pro-inflammatory mediators cytokines like TNF-α, IL-6, and PGE. Ulcerogenic liability for tested compounds demonstrated obvious gastric mucosal safety. Furthermore, a histopathological study for compound 5l suggested a confirmatory comprehensive safety profile for stomach, kidney, and heart tissues. Docking and drug-likeness studies offered a good convention with the obtained biological investigation.

Recipient Pericardial Apolipoprotein Levels Might Be an Indicator of Worse Outcomes after Orthotopic Heart Transplantation

BACKGROUND

End-stage heart failure (ESHF) leads to hypoperfusion and edema formation throughout the body and is accompanied by neurohormonal and immunological alterations. Orthotopic heart transplantation (HTX) has been used as a beneficial option for ESHF. Due to the shortage of donor hearts, the ideal matching and timing of donors and recipients has become more important.

PURPOSE

In this study, our aim was to explore the relationship between the clinical outcomes of HTX and the cytokine and apolipoprotein profiles of the recipient pericardial fluid obtained at heart transplantation after opening the pericardial sac.

MATERIALS AND METHODS

The clinical data and the interleukin, adipokine, and lipoprotein levels in the pericardial fluid of twenty HTX recipients were investigated. Outcome variables included primer graft dysfunction (PGD), the need for post-transplantation mechanical cardiac support (MCS), International Society for Heart and Lung Transplantation grade ≥2R rejection, and mortality. Recipient risk scores were also investigated.

RESULTS

Leptin levels were significantly lower in patients with PGD than in those without PGD (median: 6.36 (IQR: 5.55-6.62) versus 7.54 (IQR = 6.71-10.44); p = 0.029). Higher ApoCII levels (median: 14.91 (IQR: 11.55-21.30) versus 10.31 (IQR = 10.02-13.07); p = 0.042) and ApoCIII levels (median: 60.32 (IQR: 43.00-81.66) versus 22.84 (IQR = 15.84-33.39); p = 0.005) were found in patients (n = 5) who died in the first 5 years after HTX. In patients who exhibited rejection (n = 4) in the first month after transplantation, the levels of adiponectin (median: 74.48 (IQR: 35.51-131.70) versus 29.96 (IQR: 19.86-42.28); p = 0.039), ApoCII (median: 20.11 (IQR: 13.06-23.54) versus 10.32 (IQR: 10.02-12.84); p = 0.007), and ApoCIII (median: 70.97 (IQR: 34.72-82.22) versus 26.33 (IQR: 17.18-40.17); p = 0.029) were higher than in the nonrejection group. Moreover, the pericardial thyroxine (T4) levels (median: 3.96 (IQR: 3.49-4.46) versus 4.69 (IQR: 4.23-5.77); p = 0.022) were lower in patients with rejection than in patients who did not develop rejection.

CONCLUSION

Our results indicate that apolipoproteins can facilitate the monitoring of rejection and could be a useful tool in the forecasting of early and late complications.

Increased Risk of Coronary Artery Disease in People with Diagnosis of Neuromuscular Disorders: A Nationwide Retrospective Population-Based Case-Control Study

The existing literature has explored carpal tunnel syndrome (CTS) and determined that it could be a risk for coronary artery disease (CAD), but there has been little research comparing the relevance of CAD with other neuromuscular disorders (NMDs) to CTS. This case-control study explored the association between CTS, stenosing tenosynovitis (ST), and ulnar side NMDs and CAD. The study utilized data from Taiwan's National Health Insurance Research Database, focusing on health insurance claims. Between January 2000 and December 2011, we employed the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes to identify 64,025 CAD patients as the case group. The control group consisted of an equal number of individuals without CAD, matched for age, sex, and index year of CAD. Logistic regression analysis was employed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for each variable. Multivariate analysis, after adjusting for sociodemographic factors and comorbidities, revealed a significantly higher likelihood of a previous diagnosis of CTS in the CAD group compared to the comparison control group. However, neither ST nor the ulnar side NMDs had any statistical significance. These results indicated that median nerve injury, rather than other NMDs, may uniquely serve as a predisposing factor of CAD.

Differential Expression of Circulating Damage-Associated Molecular Patterns in Patients with Coronary Artery Ectasia

Coronary artery ectasia (CAE) is defined as abnormal dilation of a coronary artery with a diameter exceeding that of adjacent normal arterial segment by >1.5 times. CAE is a pathological entity of the coronary arteries and characterized as a variant of coronary atherosclerosis. CAE frequently coexists with coronary artery disease (CAD). While inflammation appears to be involved, the pathophysiology of CAE remains unclear. Damage-associated molecular patterns (DAMPs), defined as endogenous molecules released from stressed or damaged tissue, are deemed as alarm signals by the innate immune system. Inflammatory agents can generate DAMPs and DAMPs can create a pro-inflammatory state. In a prospective cross-sectional study, we enrolled 29 patients with CAE and non-obstructive CAD, 19 patients with obstructive CAD without CAE, and 14 control subjects with normal (control) coronary arteries age- and sex-matched with the CAE patients, to investigate the differential expression of plasma DAMPs. Patients with CAE and non-obstructive CAD had increased plasma levels of the DAMPs S100B, S100A12, HMGB1, and HSP70, the DAMPs receptor TLR4, and miR328a-3p compared to CAD and controls. Plasma levels of the mir328a-3p target the protective soluble form of the DAMPs receptor for advanced glycation end products (sRAGE), and the antioxidant DJ-1 was decreased in both CAE and CAD compared to controls. In an in vitro human umbilical vein endothelial cells model, circulating levels of S100B, HMGB1, HSP70 as well as CAE patient plasma induced inflammatory responses. The differential expression of the DAMPs S100B, HSP70, HMGB1, and their receptors TLR4 and sRAGE in CAE versus CAD makes them attractive novel biomarkers as therapeutic targets and therapeutics.

Stratification of Patients with Coronary Artery Disease by Circulating Cytokines Profile: A Pilot Study

Coronary artery disease (CAD) is a long-term inflammatory process, with atherosclerosis as its underlying pathophysiological mechanism. Endothelial dysfunction is the first step towards atherosclerosis, where damaged endothelial cells release large amounts of pro-inflammatory cytokines and mediators, thus promoting vascular inflammation and disease progression. However, the correlation between serum cytokines and CAD severity remains to be defined. Serum samples from patients performing cardiac computed tomography for suspected CAD (n = 75) were analyzed with a multiplex bead-based immunoassay panel for simultaneous assessment of the concentration of 11 cytokines using flow cytometric technology. The analysis showed statistically significant increases in sRAGE, CCL2_MCP1, FLT1, and IL6 levels in CAD patients compared with healthy subjects and a gradual increase trend towards a more severe form of the disease for most cytokines (e.g., sCD40L, FLT1, sRAGE, CCL2-MCP1, TNFα). Lastly, we explored the performance of cytokines in predicting the diagnosis of CAD and found that an increase in IL6 levels will increase the odds of being non-obstructive CAD-positive. In contrast, an increase in CCL2-MCP1 or FLT1 levels will increase the probability of being obstructive CAD-positive. These results suggest that the combination of serum cytokines may contribute to the not-invasive stratification risk for patients with suspected CAD.

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.

The role of sRAGE in cardiovascular diseases

Advanced glycation end products (AGEs), by-products of glucose metabolism, have been linked to the emergence of cardiovascular disorders (CVD). AGEs can cause tissue damage in four different ways: (1) by altering protein function, (2) by crosslinking proteins, which makes tissue stiffer, (3) by causing the generation of free radicals, and (4) by activating an inflammatory response after binding particular AGE receptors, such as the receptor for advanced glycation end products (RAGE). It is suggested that the soluble form of RAGE (sRAGE) blocks ligand-mediated pro-inflammatory and oxidant activities by serving as a decoy. Therefore, several studies have investigated the possible anti-inflammatory and anti-oxidant characteristics of sRAGE, which may help lower the risk of CVD. According to the results of various studies, the relationship between circulating sRAGE, cRAGE, and esRAGE and CVD is inconsistent. To establish the potential function of sRAGE as a therapeutic target in the treatment of cardiovascular illnesses, additional studies are required to better understand the relationship between sRAGE and CVD. In this review, we explored the potential function of sRAGE in different CVD, highlighting unanswered concerns and outlining the possibilities for further investigation.

RAGE pathways play an important role in regulation of organ fibrosis

Organ fibrosis is a pathological process of fibroblast activation and excessive deposition of extracellular matrix after persistent tissue injury and therefore is a common endpoint of many organ pathologies. Multiple cellular types and soluble mediators, including chemokines, cytokines and non-peptidic factors, are implicated in fibrogenesis and the remodeling of tissue architecture. The molecular basis of the fibrotic process is complex and consists of closely intertwined signaling networks. Research has strived for a better understanding of these pathological mechanisms to potentially reveal novel therapeutic targets for fibrotic diseases. In light of new knowledge, the receptor for advanced glycation end products (RAGE) emerged as an important candidate for the regulation of a wide variety of cellular functions related to fibrosis, including inflammation, cell proliferation, apoptosis, and angiogenesis. RAGE is a pattern recognition receptor that binds a broad range of ligands such as advanced glycation end products, high mobility group box-1, S-100 calcium-binding protein and amyloid beta protein. Although the link between RAGE and fibrosis has been established, the exact mechanisms need be investigated in further studies. The aim of this review is to collect all available information about the intricate function of RAGE and its signaling cascades in the pathogenesis of fibrotic diseases within different organs. In addition, to the major ligands and signaling pathways, we discuss potential strategies for targeting RAGE in fibrosis. We emphasize the functional links between RAGE, inflammation and fibrosis that may guide further studies and the development of improved therapeutic drugs.