Complement activation in acute myocardial infarction: An early marker of inflammation and tissue injury?

Mesenchymal stromal cells for improvement of cardiac function following acute myocardial infarction: a matter of timing

Acute myocardial infarction (AMI) is the leading cause of cardiovascular death and remains the most common cause of heart failure. Reopening of the occluded artery, i.e., reperfusion, is the only way to save the myocardium. However, the expected benefits of reducing infarct size are disappointing due to the reperfusion paradox, which also induces specific cell death. These ischemia-reperfusion (I/R) lesions can account for up to 50% of final infarct size, a major determinant for both mortality and the risk of heart failure (morbidity). In this review, we provide a detailed description of the cell death and inflammation mechanisms as features of I/R injury and cardioprotective strategies such as ischemic postconditioning as well as their underlying mechanisms. Due to their biological properties, the use of mesenchymal stromal/stem cells (MSCs) has been considered a potential therapeutic approach in AMI. Despite promising results and evidence of safety in preclinical studies using MSCs, the effects reported in clinical trials are not conclusive and even inconsistent. These discrepancies were attributed to many parameters such as donor age, in vitro culture, and storage time as well as injection time window after AMI, which alter MSC therapeutic properties. In the context of AMI, future directions will be to generate MSCs with enhanced properties to limit cell death in myocardial tissue and thereby reduce infarct size and improve the healing phase to increase postinfarct myocardial performance.

Prolonged Door-to-Balloon Time Leads to Endothelial Glycocalyx Damage and Endothelial Dysfunction in Patients with ST-Elevation Myocardial Infarction

Damage to the endothelial glycocalyx (eGC) has been reported during acute ischemic events like ST-elevation myocardial infarction (STEMI). In STEMI, a door-to-balloon time (D2B) of <60 min was shown to reduce mortality and nonfatal complications. Here, we hypothesize that eGC condition is associated with D2B duration and endothelial function during STEMI. One hundred and twenty-six individuals were analyzed in this study (STEMI patients vs. age-/sex-matched healthy volunteers). After stimulating endothelial cells with patient/control sera, the eGC's nanomechanical properties (i.e., height/stiffness) were analyzed using the atomic force microscopy-based nanoindentation technique. eGC components were determined via ELISA, and measurements of nitric oxide levels (NO) were based on chemiluminescence. eGC height/stiffness (both p < 0.001), as well as NO concentration (p < 0.001), were reduced during STEMI. Notably, the D2B had a strong impact on the endothelial condition: a D2B > 60 min led to significantly higher serum concentrations of eGC components (syndecan-1: p < 0.001/heparan sulfate: p < 0.001/hyaluronic acid: p < 0.0001). A D2B > 60 min led to the pronounced loss of eGC height/stiffness (both, p < 0.001) with reduced NO concentrations (p < 0.01), activated the complement system (p < 0.001), and prolonged the hospital stay (p < 0.01). An increased D2B led to severe eGC shedding, with endothelial dysfunction in a temporal context. eGC components and pro-inflammatory mediators correlated with a prolonged D2B, indicating a time-dependent immune reaction during STEMI, with a decreased NO concentration. Thus, D2B is a crucial factor for eGC damage during STEMI. Clinical evaluation of the eGC condition might serve as an important predictor for the endothelial function of STEMI patients in the future.

Biological Recognition-Based Electrochemical Aptasensor for Point-of-Care Detection of cTnI

As a "gold standard biomarker", cardiac troponin I (cTnI) is widely used to diagnose acute myocardial infarction (AMI). For an early clinical diagnosis of AMI, it is necessary to develop a facile, fast and on-site device for cTnI detection. According to this demand, a point-of-care electrochemical aptasensor was developed for cTnI detection by coupling the advantages of screen-printed carbon electrode (SPCE) with those of an aptamer. Thiol and methylene blue (MB) co-labelled aptamer (MB-Apt-SH) was assembled on the surface of hierarchical flower-like gold nanostructure (HFGNs)-decorated SPCE (SPCE-HFGNs) to recognize and analyze cTnI. In the presence of cTnI, the specific biological recognition reaction between cTnI and aptamer caused the decrease in electrochemical signal. Under the optimal condition, this designed aptasensor showed wide linear range (10 pg/mL-100 ng/mL) and low detection limit for (8.46 pg/mL) for cTnI detection with high selectivity and stability. More importantly, we used a mobile phone coupled with a simple APP to efficiently detect cTnI in 10 μL 100% human serum samples, proving that this aptasensor has a promising potential in point-of-care testing.

Endothelial Glycocalyx and Cardiomyocyte Damage Is Prevented by Recombinant Syndecan-1 in Acute Myocardial Infarction

The outer layer of endothelial cells (ECs), consisting of the endothelial glycocalyx (eGC) and the cortex (CTX), provides a protective barrier against vascular diseases. Structural and functional impairments of their mechanical properties are recognized as hallmarks of endothelial dysfunction and can lead to cardiovascular events, such as acute myocardial infarction (AMI). This study investigated the effects of AMI on endothelial nanomechanics and function and the use of exogenous recombinant syndecan-1 (rSyn-1), a major component of the eGC, as recovering agent. ECs were exposed in vitro to serum samples collected from patients with AMI. In addition, in situ ECs of ex vivo aorta preparations derived from a mouse model for AMI were employed. Effects were quantified by using atomic force microscopy-based nanoindentation measurements, fluorescence staining, and histologic examination of the mouse hearts. AMI serum samples damaged eGC/CTX and augmented monocyte adhesion to the endothelial surface. In particular, the anaphylatoxins C3a and C5a played an important role in these processes. The impairment of endothelial function could be prevented by rSyn-1 treatment. In the mouse model of myocardial infarction, pretreatment with rSyn-1 alleviated eGC/CTX deterioration and reduced cardiomyocyte damage in histologic analyses. However, echocardiographic measurements did not indicate a functional benefit. These results provide new insights into the underlying mechanisms of AMI-induced endothelial dysfunction and perspectives for future studies on the benefit of rSyn-1 in post-AMI treatment.

Isolation of extracellular vesicles from bitch's amnion-derived cells culture and their CD59 expression: Preliminary results

Extracellular vesicles (EVs) are small spherical particles surrounded by a membrane with an unusual lipid composition and a striking cholesterol/phospholipidic ratio. About 2000 lipid and 3500 protein species were identified in EVs secreted by different cell sources. EVs mediate cell to cell communication in proximity to or distant from the cell of origin. In particular, it was suggested that they represent modulators of multiple processes during pregnancy. The aim of this study was to identify the presence of EVs in canine amnion-derived cells (ASCs) culture and the expression of CD 59 on their surface. Amniotic membrane was collected in PBS with antibiotics added from 2 bitches during elective caesarean section. Cells culture was prepared and EVs were isolated. EVs were used to evaluate CD59 expression by flow cytofluorimetry. We found that the majority of EVs expressed CD59. Our results could increase the knowledge about the complex mechanisms that regulate the pregnancy in the bitch.

Pitfalls in complement analysis: A systematic literature review of assessing complement activation

Background

The complement system is an essential component of our innate defense and plays a vital role in the pathogenesis of many diseases. Assessment of complement activation is critical in monitoring both disease progression and response to therapy. Complement analysis requires accurate and standardized sampling and assay procedures, which has proven to be challenging.

Objective

We performed a systematic analysis of the current methods used to assess complement components and reviewed whether the identified studies performed their complement measurements according to the recommended practice regarding pre-analytical sample handling and assay technique. Results are supplemented with own data regarding the assessment of key complement biomarkers to illustrate the importance of accurate sampling and measuring of complement components.

Methods

A literature search using the Pubmed/MEDLINE database was performed focusing on studies measuring the key complement components C3, C5 and/or their split products and/or the soluble variant of the terminal C5b-9 complement complex (sTCC) in human blood samples that were published between February 2017 and February 2022. The identified studies were reviewed whether they had used the correct sample type and techniques for their analyses.

Results

A total of 92 out of 376 studies were selected for full-text analysis. Forty-five studies (49%) were identified as using the correct sample type and techniques for their complement analyses, while 25 studies (27%) did not use the correct sample type or technique. For 22 studies (24%), it was not specified which sample type was used.

Conclusion

A substantial part of the reviewed studies did not use the appropriate sample type for assessing complement activation or did not mention which sample type was used. This deviation from the standardized procedure can lead to misinterpretation of complement biomarker levels and hampers proper comparison of complement measurements between studies. Therefore, this study underlines the necessity of general guidelines for accurate and standardized complement analysis

Dexamethasone Alleviates Myocardial Injury in a Rat Model of Acute Myocardial Infarction Supported by Venoarterial Extracorporeal Membrane Oxygenation

Myocardial ischemia causes myocardial inflammation. Research indicates that the venoarterial extracorporeal membrane oxygenation (VA ECMO) provides cardiac support; however, the inflammatory response caused by myocardial ischemia remains unresolved. Dexamethasone (Dex), a broad anti-inflammatory agent, exhibits a cardioprotective effect. This study aims to investigate the effect of Dex on a rat model of acute myocardial infarction (AMI) supported by VA ECMO. Male Sprague-Dawley rats (300–350 g) were randomly divided into three groups: Sham group (n = 5), ECMO group (n = 6), and ECMO + Dex group (n = 6). AMI was induced by ligating the left anterior descending (LAD) coronary artery. Sham group only thoracotomy was performed but LAD was not ligated. The ECMO and ECMO + Dex groups were subjected to 1 h of AMI and 2 h of VA ECMO. In the ECMO + Dex group, Dex (0.2 mg/kg) was intravenously injected into the rats after 1 h of AMI. Lastly, myocardial tissue and blood samples were harvested for further evaluation. The ECMO + Dex group significantly reduced infarct size and levels of cTnI, cTnT, and CK-MB. Apoptotic cells and the expression levels of Bax, Caspase3, and Cle-Caspase3 proteins were markedly lower in the ECMO + Dex group than that in the ECMO group. Neutrophil and macrophage infiltration was lower in the ECMO + Dex group than in the ECMO group. A significant reduction was noted in ICAM-1, C5a, MMP-9, IL-1β, IL-6, and TNF-α. In summary, our findings revealed that Dex alleviates myocardial injury in a rat model of AMI supported by VA ECMO.

Assessment of Trimetazidine Treatment in Acute Myocardial Infarction Patients Undergoing Percutaneous Coronary Intervention

Aims

Trimetazidine (TMZ) is effective at improving clinical outcomes in chronic heart failure and stable coronary artery disease patients. However, no single study has comprehensively evaluated the efficacy of TMZ in acute myocardial infarction (AMI) patients undergoing percutaneous coronary intervention (PCI).

Methods

We enrolled 401 Chinese patients. All patients received the same drug prescription except for TMZ. In blinded fashion, patients were randomized to either a control or an experimental group in which 60 mg TMZ was provided at admission and then at 20 mg three times a day thereafter. At 2 and/or 6 days, we evaluated creatine kinase (CK and CK-MB), cardiac troponin I (cTnI), C-reaction protein (CRP), serum tumor necrosis factor (TNF-α), serum creatinine (Cr), serum urea, glucose, glutamic pyruvic transaminase (ALT), and glutamic oxaloacetic transaminase (AST). Additionally, by echocardiography, we assessed left ventricular ejection fraction (LVEF), left ventricular end-diastolic dimension (LVEDD), and cardiac output (CO).

Results

CK and CKMB, which were recorded on the second day in the hospital (each p=0.022), and cTNI, which was recorded on the sixth day in the hospital (p=0.003), were reduced with TMZ treatment compared to control. In addition, ALT and AST (p=0.001, p=0.000, respectively) and glucose after 6 days (p=0.011) were significantly lower in the study group than in the control group. Furthermore, LVEF after 10–14 days and 6 months after discharge (p=0.039 and p=0.047, respectively) was increased with TMZ treatment. The effects of TMZ on CRP, TNF-α, Cr, urea, LVEDD, and CO were not significant (all p > 0.05).

Conclusions

For AMI patients undergoing PCI, TMZ reduced circulating biomarkers of myocardial infarction, reduced values of ALT, AST, and glucose, and improved cardiac function compared with the control group.

Targeting vascular inflammation through emerging methods and drug carriers

Acute inflammation is a common dangerous component of pathogenesis of many prevalent conditions with high morbidity and mortality including sepsis, thrombosis, acute respiratory distress syndrome (ARDS), COVID-19, myocardial and cerebral ischemia-reperfusion, infection, and trauma. Inflammatory changes of the vasculature and blood mediate the course and outcome of the pathology in the tissue site of insult, remote organs and systemically. Endothelial cells lining the luminal surface of the vasculature play the key regulatory functions in the body, distinct under normal vs. pathological conditions. In theory, pharmacological interventions in the endothelial cells might enable therapeutic correction of the overzealous damaging pro-inflammatory and pro-thrombotic changes in the vasculature. However, current agents and drug delivery systems (DDS) have inadequate pharmacokinetics and lack the spatiotemporal precision of vascular delivery in the context of acute inflammation. To attain this level of precision, many groups design DDS targeted to specific endothelial surface determinants. These DDS are able to provide specificity for desired tissues, organs, cells, and sub-cellular compartments needed for a particular intervention. We provide a brief overview of endothelial determinants, design of DDS targeted to these molecules, their performance in experimental models with focus on animal studies and appraisal of emerging new approaches. Particular attention is paid to challenges and perspectives of targeted therapeutics and nanomedicine for advanced management of acute inflammation.

Complement C3 activation in the ICU: Disease and therapy as Bonnie and Clyde

Patients in the intensive care unit (ICU) often straddle the divide between life and death. Understanding the complex underlying pathomechanisms relevant to such situations may help intensivists select broadly acting treatment options that can improve the outcome for these patients. As one of the most important defense mechanisms of the innate immune system, the complement system plays a crucial role in a diverse spectrum of diseases that can necessitate ICU admission. Among others, myocardial infarction, acute lung injury/acute respiratory distress syndrome (ARDS), organ failure, and sepsis are characterized by an inadequate complement response, which can potentially be addressed via promising intervention options. Often, ICU monitoring and existing treatment options rely on massive intervention strategies to maintain the function of vital organs, and these approaches can further contribute to an unbalanced complement response. Artificial surfaces of extracorporeal organ support devices, transfusion of blood products, and the application of anticoagulants can all trigger or amplify undesired complement activation. It is, therefore, worth pursuing the evaluation of complement inhibition strategies in the setting of ICU treatment. Recently, clinical studies in COVID-19-related ARDS have shown promising effects of central inhibition at the level of C3 and paved the way for prospective investigation of this approach. In this review, we highlight the fundamental and often neglected role of complement in the ICU, with a special focus on targeted complement inhibition. We will also consider complement substitution therapies to temporarily counteract a disease/treatment-related complement consumption.

Amelioration of acute myocardial infarction injury through targeted ferritin nanocages loaded with an ALKBH5 inhibitor

The roles of m⁶A RNA methylation and mitochondrial metabolism in acute myocardial infarction (AMI) remain unclear. In this study, we demonstrated that m⁶A RNA methylation affected ischemia/reperfusion (I/R) injury in AMI through the "Erasers" protein ALKBH5-related metabolic reprogramming, characterized by the inhibition of enzyme activities of the tricarboxylic acid cycle; moreover, a surface-modified bioengineered ferritin nanocage was obtained from Archaeoglobus fulgidus, with a chimeric structure containing 8 lysine residues, SpyTag/SpyCatcher, and the C1q ligand Scarf1, which could disassemble and self-assemble in neutral solutions according to different Mg²⁺ concentrations. The surface-modified bioengineered ferritin nanocage targeted the dying cells in the infarct area under the guidance of Scarf1. These cells were then phagocytosed through recognition of their TfR1 receptor. Lysosomal escape was achieved through the 8 lysine residues on the nanocage, and the nanocage disassembled based on the differences in intracellular and extracellular Mg²⁺ concentrations. Finally, the ALKBH5 inhibitor IOX1 was loaded onto the ferritin nanocage and used in the AMI model, and it was found to effectively improve cardiac function. These results provide a potential strategy for the treatment of AMI in the future. STATEMENT OF SIGNIFICANCE: In acute myocardial infarction (AMI) induced by ischemia/reperfusion injury, m⁶A RNA methylation aggravates the injury through the "Erasers" protein ALKBH5-related metabolic reprogramming. To achieve precise treatment, genetic engineering-based recombinant expression technology was used to obtain a ferritin from Archaeoglobus fulgidus. The obtained ferritin was designated as HAfFtO, and it can disassemble and self-assemble in a neutral solution under different Mg²⁺ concentrations and achieve lysosomal escape. Three G4S linkers were used to connect SpyTag with HAfFtO to synthesize HAfFtO-ST and recombination Scarf1 containing SpyCatcher structure, namely SC-Sf. According to the SpyTag/SpyCatcher technique, HAfFtO-ST and SC-Sf can form a gentle and firm combination, namely HSSS. The ALKBH5 inhibitor IOX1 was loaded on HSSS to form HSSS-I. HSSS-I effectively improved the cardiac function and decreased the infarct size in AMI.

Quantitative proteomics reveal three potential biomarkers for risk assessment of acute myocardial infarction

Acute myocardial infarction (AMI) is the one of the main cause of death worldwide. Exosomes carry important information about intercellular communication and could be diagnostic marker for many diseases. Here, we aimed to find potential key proteins for the early diagnosis of AMI. A label free proteomics strategy was used to identify the differentially expressed proteins (DEPs) of AMI patients’ plasma exosome. By bioinformatics analysis and enzyme-linked immunosorbent assay to validate the candidate proteins. Compared to healthy control plasma exosome, we totally identified 72 differentially expressed proteins (DEPs) in AMI patients. Also, we found that complement and coagulation cascades was activated by KEGG analysis and GSEA. PLG, C8B and F2 were selected as candidate molecules for further study, and then validated another 40 plasma samples using enzyme-linked immunosorbent assay. Finally, we found that the expression levels of these three proteins (PLG, C8B and F2) were significantly higher than those of healthy controls (P < 0.05). ROC analysis revealed that PLG, C8B and F2 had potential value for AMI early diagnosis. In conclusion, our study identified three potential biomarkers for AMI diagnosis. But there remains a need to further study the mechanism of the biomarkers.

Potential biomarkers of acute myocardial infarction based on co‑expression network analysis

Acute myocardial infarction (AMI) is a common cause of death in numerous countries. Understanding the molecular mechanisms of the disease and analyzing potential biomarkers of AMI is crucial. However, specific diagnostic biomarkers have thus far not been fully established and candidate regulatory targets for AMI remain to be determined. In the present study, the AMI gene chip dataset GSE48060 comprising blood samples from control subjects with normal cardiac function (n=21) and patients with AMI (n=26) was downloaded from Gene Expression Omnibus. The differentially expressed genes (DEGs) between the AMI and control groups were identified with the online tool GEO2R. The co-expression network of DEGs was analyzed by calculating the Pearson correlation coefficient of all gene pairs, mutual rank screening and cutoff threshold screening. Subsequently, the Gene Ontology (GO) database was used to analyze the genes' functions and pathway enrichment of genes in the most important modules was performed. Kyoto Encyclopedia of Genes and Genomes (KEGG) Disease and BioCyc were used to analyze the hub genes in the module to determine important sub-pathways. In addition, the expression of hub genes was confirmed by reverse transcription-quantitative PCR in AMI and control specimens. In the present study, 52 DEGs, including 26 upregulated and 26 downregulated genes, were identified. As key hub genes, three upregulated genes (AKR1C3, RPS24 and P2RY12) and three downregulated genes (ACSL1, B3GNT5 and MGAM) were identified from the co-expression network. Furthermore, GO enrichment analysis of all AMI co-expression network genes revealed functional enrichment mainly in ‘RAGE receptor binding’ and ‘negative regulation of T cell cytokine production’. In addition, KEGG Disease and BioCyc analysis indicated functional enrichment of the genes RPS24 and P2RY12 in ‘cardiovascular diseases’, of AKR1C3 in ‘cardenolide biosynthesis’, of MGAM in ‘glycogenolysis’, of B3GNT5 in ‘glycosphingolipid biosynthesis’ and of ACSL1 in ‘icosapentaenoate biosynthesis II’. In conclusion, the hub genes AKR1C3, RPS24, P2RY12, ACSL1, B3GNT5 and MGAM are potential markers of AMI, and have potential application value in the diagnosis of AMI.

NONMMUT140591.1 may serve as a ceRNA to regulate Gata5 in UT-B knockout-induced cardiac conduction block

We intended to explore the potential molecular mechanisms underlying the cardiac conduction block inducted by urea transporter (UT)-B deletion at the transcriptome level. The heart tissues were harvested from UT-B null mice and age-matched wild-type mice for lncRNA sequencing analysis. Based on the sequencing data, the differentially expressed mRNAs (DEMs) and lncRNAs (DELs) between UT-B knockout and control groups were identified, followed by function analysis and mRNA-lncRNA co-expression analysis. The miRNAs were predicted, and then the competing endogenous RNA (ceRNA) network was constructed. UT-B deletion results in the aberrant expression of 588 lncRNAs and 194 mRNAs. These DEMs were significantly enriched in the inflammation-related pathway. A lncRNA-mRNA co-expression network and a ceRNA network were constructed on the basis of the DEMs and DELs. The complement 7 (C7)-NONMMUT137216.1 co-expression pair had the highest correlation coefficient in the co-expression network. NONMMUT140591.1 had the highest degree in the ceRNA network and was involved in the ceRNA of NONMMUT140591.1-mmu-miR-298-5p-Gata5 (GATA binding protein 5). UT-B deletion may promote cardiac conduction block via inflammatory process. The ceRNA NONMMUT140591.1-mmu-miR-298-5p-Gata5 may be a potential molecular mechanism of UT-B knockout-induced cardiac conduction block.

Membrane Attack Complex in Myocardial Ischemia/Reperfusion Injury: A Systematic Review for Post Mortem Applications

The complement system has a significant role in myocardial ischemia/reperfusion injury, being responsible for cell lysis and amplification of inflammatory response. In this context, several studies highlight that terminal complement complex C5b-9, also known as the membrane attack complex (MAC), is a significant contributor. The MAC functions were studied by many researchers analyzing the characteristics of its activation in myocardial infarction. Here, a systematic literature review was reported to evaluate the principal features, advantages, and limits (regarding the application) of complement components and MAC in post mortem settings to perform the diagnosis of myocardial ischemia/infarction. The review was performed according to specific inclusion and exclusion criteria, and a total of 26 studies were identified. Several methods studied MAC, and each study contributes to defining better how and when it affects the myocardial damage in ischemic/reperfusion injury. The articles were discussed, focusing on the specificity, sensibility, and post mortem stability of MAC as a marker of myocardial ischemia/infarction, supporting the usefulness in routine post mortem investigations.

Inflammation in myocardial injury- Stem cells as potential immunomodulators for myocardial regeneration and restoration

The ineffective immunosuppressant's and targeted strategies to neutralize inflammatory mediators have worsened the scenario of heart failure and have opened many questions for debate. Stem cell therapy has proven to be a promising approach for treating heart following myocardial infarction (MI). Adult stem cells, induced pluripotent stem cells and embryonic stem cells are possible cell types and have successfully shown to regenerate damaged myocardial tissue in pre-clinical and clinical studies. Current implications of using mesenchymal stem cells (MSCs) owing to their immunomodulatory functions and paracrine effects could serve as an effective alternative treatment option for rejuvenating the heart post MI. The major setback associated with the use of MSCs is reduced cell retention, engraftment and decreased effectiveness. With a few reports on understanding the role of inflammation and its dual effects on the structure and function of heart, this review focuses on these missing insights and further exemplifies the role of MSCs as an alternative therapy in treating the pathological consequences in myocardial infarction (MI).

The role of the complement factor B-arginase-polyamine molecular axis in uremia-induced cardiac remodeling in mice

The role of complement system in heart diseases is controversial. Besides, the mechanisms by which complement components participate in cardiac remodeling (CR) and heart failure during uremia are unclear. In this study, 5/6 nephrectomy was performed to adult mice to establish the uremic model and CR deteriorated over the course of uremia. Although complement pathways were not further activated over the course of the disease, soluble complement factor B (CFB) was upregulated at post-nephrectomy day 90 (PNx90) compared with PNx30. Further, CFB notably deteriorated CR in uremic mice but this effect was reversed by depletion of macrophages with liposomal clodronate. In vivo and in vitro CFB upregulated arginase 1 (ARG1) expression, increased ARG1 enzymatic activity, and stimulated the syntheses of ornithine, leading to polyamine overproduction in macrophages. Putrescine, an important polyamine, promoted cardiac fibroblast proliferation and collagen production, resulting in progressive CR. In vivo the inhibition of ARG1 activity with N^ω -hydroxyl-l-arginine remarkably improved the general survival rates, inhibited the infiltration of cardiac fibroblasts, and alleviated progression of CR in uremic mice. Taken together, the CFB-ARG1-putrescine axis is related to progression of CR and ARG1 hyperactivity in macrophages may provide a novel therapeutic target against the heart injury in uremia.

Alterations in complement and coagulation pathways of human placentae subjected to in vitro fertilization and embryo transfer in the first trimester

The mechanisms underlying the potential risks of in vitro fertilization and embryo transfer (IVF-ET) have not been fully elucidated. The aim of this study was to explore changes in the complement and coagulation pathways in placentae subjected to IVF-ET in the first trimester compared to placentae from normal pregnancies. Four placenta samples in the first trimester were obtained from patients undergoing IVF-ET owing to oviductal factors only. An additional 4 control placentae were obtained from volunteers with normal pregnancies. A GeneChip Affymetrix HG-U133 Plus 2.0 Array was utilized to analyze the changes in gene expression between the normal and IVF-ET placentae. Differentially expressed genes (DEGs) were analyzed using the Database for Annotation and Visualization and Integrated Discovery bioinformatics resource, and gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted. Using real-time PCR, we confirmed the obtained microarray data in 10 dysregulated genes. Five of the gene products were further analyzed by immunohistochemistry (IHC) to determine their protein expression and localization. A total of fifty DEGs were identified in the complement and coagulation pathways in the IVF-ET treated placentae: 38 upregulated and 12 down-regulated. KEGG pathway analysis indicated that IVF-ET manipulation substantially over-activated the coagulation and complement pathways, while urokinase plasminogen activator- and urokinase plasminogen activator receptor-mediated trophoblastic invasion and tissue remodeling were inhibited. Furthermore, the 5 proteins analyzed by IHC were found to be localized specifically to the placenta. This is the first study to compare DEGs relating to the placental complement and coagulation pathways from patients undergoing IVF-ET treatment compared to those undergoing normal pregnancy. These findings identified valuable biomarkers and potential novel therapeutic targets to combat the unfavorable effects of IVF-ET.

Inflammation in myocardial injury: mesenchymal stem cells as potential immunomodulators

Ischemic heart disease is a growing worldwide epidemic. Improvements in medical and surgical therapies have reduced early mortality after acute myocardial infarction and increased the number of patients living with chronic heart failure. The irreversible loss of functional cardiomyocytes puts these patients at significant risk of ongoing morbidity and mortality after their index event. Recent evidence suggests that inflammation is a key mediator of postinfarction adverse remodeling in the heart. In this review, we discuss the cardioprotective and deleterious effects of inflammation and its mediators during acute myocardial infarction. We also explore the role of mesenchymal stem cell therapy to limit secondary injury and promote myocardial healing after myocardial infarction.

Safety profile after prolonged C3 inhibition

The central component of the complement cascade, C3, is involved in various biological functions, including opsonization of foreign bodies, clearance of waste material, activation of immune cells, and triggering of pathways controlling development. Given its broad role in immune responses, particularly in phagocytosis and the clearance of microbes, a deficiency in complement C3 in humans is often associated with multiple bacterial infections. Interestingly, an increased susceptibility to infections appears to occur mainly in the first two years of life and then wanes throughout adulthood. In view of the well-established connection between C3 deficiency and infections, therapeutic inhibition of complement at the level of C3 is often considered with caution or disregarded. We therefore set out to investigate the immune and biochemical profile of non-human primates under prolonged treatment with the C3 inhibitor compstatin (Cp40 analog). Cynomolgus monkeys were dosed subcutaneously with Cp40, resulting in systemic inhibition of C3, for 1 week, 2 weeks, or 3 months. Plasma concentrations of both C3 and Cp40 were measured periodically and complete saturation of plasma C3 was confirmed. No differences in hematological, biochemical, or immunological parameters were identified in the blood or tissues of animals treated with Cp40 when compared to those injected with vehicle alone. Further, skin wounds showed no signs of infection in those treated with Cp40. In fact, Cp40 treatment was associated with a trend toward accelerated wound healing when compared with the control group. In addition, a biodistribution study in a rhesus monkey indicated that the distribution of Cp40 in the body is associated with the presence of C3, concentrating in organs that accumulate blood and produce C3. Overall, our data suggest that systemic C3 inhibition in healthy adult non-human primates is not associated with a weakened immune system or susceptibility to infections.