Antibodies against Angiotensin II Type 1 and Endothelin 1 Type A Receptors in Cardiovascular Pathologies

Are fetal microchimerism and circulating fetal extracellular vesicles important links between spontaneous preterm delivery and maternal cardiovascular disease risk?

Trafficking and persistence of fetal microchimeric cells (fMCs) and circulating extracellular vesicles (EVs) have been observed in animals and humans, but their consequences in the maternal body and their mechanistic contributions to maternal physiology and pathophysiology are not yet fully defined. Fetal cells and EVs may help remodel maternal organs after pregnancy-associated changes, but the cell types and EV cargos reaching the mother in preterm pregnancies after exposure to various risk factors can be distinct from term pregnancies. As preterm delivery-associated maternal complications are rising, revisiting this topic and formulating scientific questions for future research to reduce the risk of maternal morbidities are timely. Epidemiological studies report maternal cardiovascular risk as one of the major complications after preterm delivery. This paper suggests a potential link between fMCs and circulating EVs and adverse maternal cardiovascular outcomes post-pregnancies, the underlying mechanisms, consequences, and methods for and how this link might be assessed.

Association of Angiotensin II Receptor Type 1 and Endothelin-1 Receptor Type A Agonistic Autoantibodies With Adverse Remodeling and Cardiovascular Events After Acute Myocardial Infarction

BACKGROUND

The left ventricular remodeling (LVR) process has limited the effectiveness of therapies after myocardial infarction. The relationship between autoantibodies activating AT1R-AAs (angiotensin II receptor type 1-AAs) and ETAR-AAs (autoantibodies activating endothelin-1 receptor type A) with myocardial infarction has been described. Among patients with ST-segment-elevation myocardial infarction, we investigated the relationship between these autoantibodies with LVR and subsequent major adverse cardiac events.

METHODS AND RESULTS

In this prospective observational study, we included 131 patients with ST-segment-elevation myocardial infarction (61±11 years of age, 112 men) treated with primary percutaneous coronary intervention. Within 48 hours of admission, 2-dimensional transthoracic echocardiography was performed, and blood samples were obtained. The seropositive threshold for AT1R-AAs and ETAR-AAs was >10 U/mL. Patients were followed up at 6 months, when repeat transthoracic echocardiography was performed. The primary end points were LVR, defined as a 20% increase in left ventricular end-diastolic volume index, and major adverse cardiac event occurrence at follow-up, defined as cardiac death, nonfatal re-myocardial infarction, and hospitalization for heart failure. Forty-one (31%) patients experienced LVR. The prevalence of AT1R-AAs and ETAR-AAs seropositivity was higher in patients with versus without LVR (39% versus 11%, P<0.001 and 37% versus 12%, P=0.001, respectively). In multivariable analysis, AT1R-AAs seropositivity was significantly associated with LVR (odds ratio [OR], 4.66; P=0.002) and represented a risk factor for subsequent major adverse cardiac events (OR, 19.6; P=0.002).

CONCLUSIONS

AT1R-AAs and ETAR-AAs are associated with LVR in patients with ST-segment-elevation myocardial infarction. AT1R-AAs are also significantly associated with recurrent major adverse cardiac events. These initial observations may set the stage for a better pathophysiological understanding of the mechanisms contributing to LVR and ST-segment-elevation myocardial infarction prognosis.

Autoantibodies Targeting G-Protein-Coupled Receptors: Pathogenetic, Clinical and Therapeutic Implications in Systemic Sclerosis

Systemic sclerosis (SSc) is a multifaceted connective tissue disease whose aetiology remains largely unknown. Autoimmunity is thought to play a pivotal role in the development of the disease, but the direct pathogenic role of SSc-specific autoantibodies remains to be established. The recent discovery of functional antibodies targeting G-protein-coupled receptors (GPCRs), whose presence has been demonstrated in different autoimmune conditions, has shed some light on SSc pathogenesis. These antibodies bind to GPCRs expressed on immune and non-immune cells as their endogenous ligands, exerting either a stimulatory or inhibitory effect on corresponding intracellular pathways. Growing evidence suggests that, in SSc, the presence of anti-GPCRs antibodies correlates with specific clinical manifestations. Autoantibodies targeting endothelin receptor type A (ETAR) and angiotensin type 1 receptor (AT1R) are associated with severe vasculopathic SSc-related manifestations, while anti-C-X-C motif chemokine receptors (CXCR) antibodies seem to be predictive of interstitial lung involvement; anti-muscarinic-3 acetylcholine receptor (M3R) antibodies have been found in patients with severe gastrointestinal involvement and anti-protease-activated receptor 1 (PAR1) antibodies have been detected in patients experiencing scleroderma renal crisis. This review aims to clarify the potential pathogenetic significance of GPCR-targeting autoantibodies in SSc, focusing on their associations with the different clinical manifestations of scleroderma. An extensive examination of functional autoimmunity targeting GPCRs might provide valuable insights into the underlying pathogenetic mechanisms of SSc, thus enabling the development of novel therapeutic strategies tailored to target GPCR-mediated pathways.

Baicalin-peptide supramolecular self-assembled nanofibers effectively inhibit ferroptosis and attenuate doxorubicin-induced cardiotoxicity

Doxorubicin, an anthracycline chemotherapeutic agent, elicits a deleterious cardiotoxicity known as doxorubicin-induced cardiomyopathy (DIC) that circumscribes its chemotherapy utility for malignancies. Recent empirical evidence implicates ferroptosis, an iron-dependent form of regulated cell death, as playing a pivotal role in the pathogenesis of DIC. We postulated that anti-ferroptosis agents may constitute a novel therapeutic strategy for mitigating DIC. To test this hypothesis, we engineered baicalin-peptide supramolecular self-assembled nanofibers designed to selectively target the angiotensin II type I receptor (AT1R), which is upregulated in doxorubicin-damaged cardiomyocytes. This enabled targeted delivery of baicalin, a natural antioxidant compound, to inhibit ferroptosis in the afflicted myocardium. In vitro, the nanofibers ameliorated cardiomyocyte death by attenuating peroxide accumulation and suppressing ferroptosis. In a murine model of DIC, AT1R-targeted baicalin delivery resulted in efficacious cardiac accumulation and superior therapeutic effects compared to systemic administration. This investigation delineates a promising framework for developing targeted therapies that alleviate doxorubicin-induced cardiotoxicity by inhibiting the ferroptosis pathway in cardiomyocytes.

Spontaneous coronary artery dissection in women with acute myocardial infarction: is there a new role for autoimmunity?

AIMS

Spontaneous coronary artery dissection (SCAD) is an uncommon cause of acute myocardial infarction in women and has an unclear pathophysiology. Autoantibodies (AAs) targeting angiotensin-II receptor type 1 (AT1R) and endothelin-1 receptor type A (ETAR) have known detrimental effects on endothelial function. We investigated the prevalence of these AAs in SCAD-affected female patients.

METHODS AND RESULTS

Female patients diagnosed at coronary angiography with myocardial infarction and SCAD were consecutively enrolled. Autoantibodies targeting angiotensin-II receptor type 1 and ETAR-AA titres and seropositivity prevalence were compared between SCAD patients, ST-elevation myocardial infarction (STEMI) patients, and healthy women. Ten women with SCAD and 20 age-matched controls (10 women with STEMI and 10 healthy women) were included. Six out of 10 (60%) women with myocardial infarction and SCAD were seropositive for AT1R-AAs and ETAR-AAs. In contrast, only one (10%) healthy woman and one (10%) STEMI patient were seropositive for AT1R-AAs (P = 0.03 and P = 0.03, respectively). One STEMI patient was seropositive for ETAR-AAs, while none of the healthy women was found to be seropositive (P = 0.03 and P = 0.01, respectively). The median AA titre was significantly higher in SCAD patients than in healthy women (P = 0.01 for AT1R-AAs; P = 0.02 for ETAR-AAs) and STEMI patients (P < 0.001 for AT1R-AAs; P = 0.002 for ETAR-AAs).

CONCLUSION

Autoantibodies targeting angiotensin-II receptor type 1 and ETAR-AA seropositivity is significantly higher in SCAD women with myocardial infarction than in healthy women or female patients with STEMI. Our findings, corroborated by previous data in the literature and biological plausibility, suggest a possible role for AT1R-AAs and ETAR-AAs in the pathophysiology of SCAD in women with acute myocardial infarction and should warrant further studies with larger sample sizes.

Cisplatin treatment reduces contraction to angiotensin II by altering expression of angiotensin II receptors: a pilot study

The renin angiotensin system is a key regulator of blood pressure homeostasis. Angiotensin type 1 (AT1R) and 2 receptors (AT2R) have been investigated as targets for cisplatin-induced acute kidney injury; however, their therapeutic potential remains inconclusive. This pilot study aimed to determined the effect that acute cisplatin treatment had on angiotensin II (AngII)-induced contraction in blood vessels and expression profiles of AT1R and AT2R in mouse arteries and kidneys. Male C57BL/6 mice at 18 week of age (n = 8) were treated with vehicle or bolus dose of cisplatin (12.5 mg/kg). Thoracic aorta (TA), adnominal aorta (AA), brachiocephalic arteries (BC), iliac arteries (IL) and kidneys were collected for isometric tension and immunohistochemistry analysis. Cisplatin treatment reduced IL contraction to AngII at all doses (p < 0.01, p < 0.001, p < 0.0001); however, AngII did not induce contraction in TA, AA or BC in either treatment group. Following cisplatin treatment, AT1R expression was significantly upregulated in the media of TA (p < 0.0001) and AA (p < 0.0001), and in the endothelium (p < 0.05) media (p < 0.0001) and adventitia (p < 0.01) of IL. Cisplatin treatment significantly reduced AT2R expression in the endothelium (p < 0.05) and media (p < 0.05) of TA. In renal tubules, both AT1R (p < 0.01) and AT2R (p < 0.05) were increased following cisplatin treatment. Herein, we report that cisplatin reduces AngII-mediated contraction in IL and may be explained by an absence of normal counterregulatory expression of AT1R and AT2R, indicating other factors are involved.

Identification of novel first-trimester serum biomarkers for early prediction of preeclampsia

BACKGROUND

Preeclampsia (PE) is a leading cause of maternal and perinatal mortality and morbidity worldwide, but effective early prediction remains a challenge due to the lack of reliable biomarkers.

METHODS

Based on the extensive human biobank of our large-scale assisted reproductive cohort platform, the first-trimester serum levels of 48 cytokines, total immunoglobulins (Igs), anti-phosphatidylserine (aPS) antibodies, and several previously reported PE biomarkers [including placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and activin A] were measured in 34 women diagnosed with PE and 34 matched normotensive controls.

RESULTS

The PE group has significantly higher first-trimester serum levels of interleukin (IL)-2Rα, IL-9, tumor necrosis factor-β (TNF-β), RANTES, hepatocyte growth factor (HGF), total IgM, and total IgG, and aPS IgG optical density (OD) value, as well as lower first-trimester serum levels of PlGF and total IgA and aPS-IgG immune complexes (IC) OD value than the control group. Combining top five first-trimester serum biomarkers (total IgM, total IgG, PlGF, aPS IgG, and total IgA) achieved superior predictive value [area under the curve (AUC) and 95% confidence interval (CI) 0.983 (0.952-1.000), with a sensitivity of 100% and a specificity of 94.1%] for PE development compared to PlGF and PlGF/sFlt-1 independently [AUC and 95% CI 0.825 (0.726-0.924) and 0.670 (0.539-0.800), respectively].

CONCLUSION

We identified novel first-trimester serum biomarkers and developed an effective first-trimester prediction model using immune-related factors and PlGF for PE, which could facilitate the development of early diagnostic strategies and provide immunological insight into the further mechanistic exploration of PE.

Association of autoantibodies targeting endothelin type-A receptors with no-reflow in ST-elevation myocardial infarction

BACKGROUND AND AIMS

No-reflow (NR), where the coronary artery is patent after treatment of ST-elevation myocardial infarction (STEMI) but tissue perfusion is not restored, is associated with worse outcomes. We aimed to investigate the relationship between autoantibodies activating endothelin-1 receptor type A (ETAR-AAs) and NR after primary percutaneous coronary intervention (PPCI) in STEMI.

METHODS

We studied 50 patients (age 59 ± 11 years, 40 males) with STEMI who underwent PPCI within 6 h after the onset of symptoms. Blood samples were obtained from all patients within 12 h following PPCI for ETAR-AA level measurement. The seropositive threshold was provided by the manufacturer (>10 U/ml). NR was assessed by cardiac magnetic resonance imaging (MVO, microvascular obstruction). As a control group, 40 healthy subjects matched for age and sex were recruited from the general population.

RESULTS

MVO was observed in 24 patients (48%). The prevalence of MVO was higher in patients with ETAR-AAs seropositivity (72% vs. 38%, p = 0.03). ETAR-AAs were higher in patients with MVO (8.9 U/mL (interquartile range [IQR] 6.8-16.2 U/mL) vs. 5.7 U/mL [IQR 4.3-7.7 U/mL], p = 0.003). ETAR-AAs seropositivity was independently associated with MVO (OR 3.2, 95% CI 1.3-7.1; p = 0.03). We identified ≥6.74 U/mL as the best cut-off for prediction of MVO (sensitivity 79%; specificity 65%; NPV 71%; PPV 74%; accuracy 72%).

CONCLUSIONS

The ETAR-AAs seropositivity is associated with NR in STEMI patients. These findings may open up new options in the management of myocardial infarction even if confirmation in a larger trial is needed.

The Impacts of Animal-Based Diets in Cardiovascular Disease Development: A Cellular and Physiological Overview

Cardiovascular disease (CVD) is the leading cause of death in the United States, and diet plays an instrumental role in CVD development. Plant-based diets have been strongly tied to a reduction in CVD incidence. In contrast, animal food consumption may increase CVD risk. While increased serum low-density lipoprotein (LDL) cholesterol concentrations are an established risk factor which may partially explain the positive association with animal foods and CVD, numerous other biochemical factors are also at play. Thus, the aim of this review is to summarize the major cellular and molecular effects of animal food consumption in relation to CVD development. Animal-food-centered diets may (1) increase cardiovascular toll-like receptor (TLR) signaling, due to increased serum endotoxins and oxidized LDL cholesterol, (2) increase cardiovascular lipotoxicity, (3) increase renin-angiotensin system components and subsequent angiotensin II type-1 receptor (AT1R) signaling and (4) increase serum trimethylamine-N-oxide concentrations. These nutritionally mediated factors independently increase cardiovascular oxidative stress and inflammation and are all independently tied to CVD development. Public policy efforts should continue to advocate for the consumption of a mostly plant-based diet, with the minimization of animal-based foods.

Renin-Angiotensin System and Sex Differences in COVID-19: A Critical Assessment

The current epidemic of corona virus disease (COVID-19) has resulted in an immense health burden that became the third leading cause of death and potentially contributed to a decline in life expectancy in the United States. The severe acute respiratory syndrome-related coronavirus-2 binds to the surface-bound peptidase angiotensin-converting enzyme 2 (ACE2, EC 3.4.17.23) leading to tissue infection and viral replication. ACE2 is an important enzymatic component of the renin-angiotensin system (RAS) expressed in the lung and other organs. The peptidase regulates the levels of the peptide hormones Ang II and Ang-(1-7), which have distinct and opposing actions to one another, as well as other cardiovascular peptides. A potential consequence of severe acute respiratory syndrome-related coronavirus-2 infection is reduced ACE2 activity by internalization of the viral-ACE2 complex and subsequent activation of the RAS (higher ratio of Ang II:Ang-[1-7]) that may exacerbate the acute inflammatory events in COVID-19 patients and possibly contribute to the effects of long COVID-19. Moreover, COVID-19 patients present with an array of autoantibodies to various components of the RAS including the peptide Ang II, the enzyme ACE2, and the AT1 AT2 and Mas receptors. Greater disease severity is also evident in male COVID-19 patients, which may reflect underlying sex differences in the regulation of the 2 distinct functional arms of the RAS. The current review provides a critical evaluation of the evidence for an activated RAS in COVID-19 subjects and whether this system contributes to the greater severity of severe acute respiratory syndrome-related coronavirus-2 infection in males as compared with females.

Mechanism Underlying Triple VEGFR Inhibitor Tivozanib-Induced Hypertension in Mice Model

Tivozanib is a triple vascular endothelial growth factor receptor inhibitor, recently approved for the treatment of refractory advanced renal cell carcinoma. Clinical studies showed that around 46% of patients who received tivozanib suffer from hypertension in all grades. Thus, the present study was conducted to identify the role of angiotensin-II (AngII) in the mechanism underlying tivozanib-induced vascular toxicity and hypertension. C57BL/6 male mice received tivozanib (1 mg/kg) with or without losartan (10 or 30 mg/kg) for 3 weeks. Blood pressure was recorded every 3 days, and proteinuria was measured every week. On day 21, all mice were euthanized, and samples were harvested for further analysis. Tivozanib elevated blood pressure until systolic blood pressure reached 163 ± 6.6 mmHg on day 21 of treatment with low urination and high proteinuria. AngII and its receptors, endothelin-1, and oxidative stress markers were significantly increased. While nitric oxide (NO) levels were reduced in plasma and aortic tissues. AngII type 1 receptor blockade by losartan prevented these consequences caused by tivozanib and kept blood pressure within normal range. The results showed that AngII and ET-1 might be potential targets in the clinical studies and management of hypertension induced by tivozanib.

Effectiveness of losartan on infrapatellar fat pad/synovial fibrosis and pain behavior in the monoiodoacetate-induced rat model of osteoarthritis pain

Infrapatellar fat pad (IFP)/ synovial fibrosis is closely associated with the clinical symptoms of joint pain and stiffness, which contribute to locomotor restriction in osteoarthritis (OA) patients. Hence, this study was designed to gain insight on whether losartan, a selective angiotensin II type 1 receptor (AT1R) antagonist, has therapeutic benefit to reverse IFP/synovial fibrosis and secondarily to attenuate pain behavior. In male Wistar rats with monoiodoacetic acid (MIA)-induced IFP/synovial fibrosis, a possible role for increased AT1R expression in the pathogenesis of IFP/synovial fibrosis was assessed over an 8-week period. Pain behavior comprised static weight bearing and von Frey paw withdrawal thresholds (PWTs), which were assessed once or twice weekly, respectively. Groups of MIA-rats received oral losartan (30-mg/kg; n = 8 or 100-mg/kg; n = 9) or vehicle (n = 9) for 28-days according to a prevention protocol. Animals were euthanized on day 28 and various tissues (IFP/synovium, cartilage and lumbar dorsal root ganglia (DRGs)) were collected for histological, immunohistochemical and western blot analyses. Administration of once-daily losartan for 28-days dose-dependently attenuated the development of static weight bearing. This was accompanied by reduced IFP/synovial fibrosis and suppression of TGF-β1 expression. Chronic treatment of MIA-rats with losartan had an anti-fibrotic effect and it attenuated pain behavior in this animal model.

Elevated Plasma Immunoglobulin Levels Prior to Heart Transplantation Are Associated with Poor Post-Transplantation Survival

Cardiac allograft vasculopathy (CAV) and antibody-mediated rejection are immune-mediated, long-term complications that jeopardize graft survival after heart transplantation (HTx). Interestingly, increased plasma levels of immunoglobulins have been found in end-stage heart failure (HF) patients prior to HTx. In this study, we aimed to determine whether increased circulating immunoglobulin levels prior to transplantation are associated with poor post-HTx survival. Pre-and post-HTx plasma samples of 36 cardiac transplant recipient patients were used to determine circulating immunoglobulin levels. In addition, epicardial tissue was collected to determine immunoglobulin deposition in cardiac tissue and assess signs and severity of graft rejection. High levels of IgG1 and IgG2 prior to HTx were associated with a shorter survival post-HTx. Immunoglobulin deposition in cardiac tissue was significantly elevated in patients with a survival of less than 3 years. Patients with high plasma IgG levels pre-HTx also had significantly higher plasma levels after HTx. Furthermore, high pre-HTX levels of IgG1 and IgG2 levels were also significantly increased in patients with inflammatory infiltrate in CAV lesions. Altogether the results of this proof-of-concept study suggest that an activated immune response prior to transplantation negatively affects graft survival.

The Relationship between Serum CXCL8 and ET-1 Expression Levels and Sepsis Complicated with Heart Failure

Objective. The objective is to investigate the relationship between sepsis complicated with heart failure and the expression levels of CXC chemokine ligand 8 (CXCL8) and endothelin-1 (ET-1). Methods. A total of 128 sepsis patients accepted by the Ganzhou People’s Hospital from March 2019 to December 2021 were collected as observation objects, and they were separated into a simple sepsis group (86 cases) and a complicated heart failure group (42 cases) according to whether they were accompanied by heart failure or not. General data such as Sequential Organ Failure Assessment (SOFA) score and Acute Physiology and Chronic Health Evaluation II (APACHE II) were collected; the expression levels of serum CXCL8 and ET-1 were detected by enzyme-linked immunosorbent assay (ELISA); the cardiac function parameters such as left ventricular ejection fraction (LVEF), stroke volume (SV), cardiac output (CO), and cardiac index (CI) were measured by color Doppler ultrasound; the correlation between serum CXCL8 and ET-1 expression levels with clinical data and cardiac function parameters in patients with sepsis complicated with heart failure was analyzed by the Pearson correlation; and the influencing factors of sepsis complicated with heart failure were analyzed by the logistic regression analysis. Results. The serum CXCL8 and ET-1 expression levels, SOFA score, and APACHE II score in the complicated heart failure group were higher than those in the simple sepsis group ( $P<0.05$ ), and LVEF, SV, CO, and CI in the complicated heart failure group were lower than those in the simple sepsis group ( $P<0.05$ ). Serum CXCL8 was positively correlated with ET-1 in patients with sepsis complicated with heart failure (r = 0.531, $P<0.05$ ), and the two were positively correlated with SOFA score and APACHE II score ( $P<0.05$ ) and were negatively correlated with LVEF, SV, CO, and CI ( $P<0.05$ ). CXCL8 and ET-1 were independent risk factors for sepsis complicated with heart failure ( $P<0.05$ ). Conclusion. The expression levels of serum CXCL8 and ET-1 in sepsis patients with heart failure are significantly increased, and both are risk factors for heart failure in sepsis patients.