Abstract Objectives An assay for molecular imaging of myocardial CXCR4 expression was evaluated, in order to obtain mechanistic insights noninvasively based on quantitative positron emission ...tomography (PET). Background The chemokine receptor CXCR4 has emerged as a therapeutic target after acute myocardial infarction (AMI), because of its role in inflammatory and progenitor cell recruitment. Methods PET with the specific CXCR4 ligand, gallium-68 (68 Ga)-pentixafor, was performed in mice (n = 53) and compared with ex vivo autoradiography, immunohistochemistry, and left ventricular flow cytometry. In addition, 12 patients were imaged at 2 to 8 days after AMI. Results In mice,68 Ga-pentixafor identified regional CXCR4 upregulation in the infarct region, peaking at 3 days (infarct/remote I/R ratio 1.5 ± 0.2 at 3 days vs. 1.2 ± 0.3 at 7 days; p = 0.03), corresponding to a flow cytometry-based peak of CD45+ leukocytes and immunohistochemical detection of CD68+ macrophages and Ly6G+ granulocytes. Blockade with the CXCR4 antagonist AMD3100 abolished the signal. No specific uptake was found in sham-operated or control animals. Long-term treatment with oral enalapril attenuated the CXCR4 signal (I/R 1.2 ± 0.2 at 3 days and 1.0 ± 0.0.1 at 7 days; p = 0.01 vs. untreated). Patients showed variable degrees of CXCR4 upregulation in the infarct region. No single clinical parameter allowed for prediction of CXCR4 signal strength. At multivariate analysis, a combination of infarct size and time after reperfusion predicted the CXCR4 infarct signal (rmultiple = 0.73; p = 0.03). Infarct signal in the myocardium was paralleled by elevated pentixafor uptake in bone marrow (r = 0.61; p = 0.04), which highlighted systemic interactions. Conclusions Targeted PET imaging with68 Ga-pentixafor identifies the global and regional CXCR4 expression pattern in myocardium and systemic organs. CXCR4 upregulation after AMI coincides with inflammatory cell infiltration, but shows interindividual variability in patients. This may have implications for the response to CXCR4- or other inflammation-targeted therapy, and for subsequent ventricular remodeling.
An anti-angiogenic cleaved prolactin fragment is considered causal for peripartum cardiomyopathy (PPCM). Experimental and first clinical observations suggested beneficial effects of the prolactin ...release inhibitor bromocriptine in PPCM.
In this multicentre trial, 63 PPCM patients with left ventricular ejection fraction (LVEF) ≤35% were randomly assigned to short-term (1W: bromocriptine, 2.5 mg, 7 days) or long-term bromocriptine treatment (8W: 5 mg for 2 weeks followed by 2.5 mg for 6 weeks) in addition to standard heart failure therapy. Primary end point was LVEF change (delta) from baseline to 6 months assessed by magnetic resonance imaging. Bromocriptine was well tolerated. Left ventricular ejection fraction increased from 28 ± 10% to 49 ± 12% with a delta-LVEF of + 21 ± 11% in the 1W-group, and from 27 ± 10% to 51 ± 10% with a delta-LVEF of + 24 ± 11% in the 8W-group (delta-LVEF: P = 0.381). Full-recovery (LVEF ≥ 50%) was present in 52% of the 1W- and in 68% of the 8W-group with no differences in secondary end points between both groups (hospitalizations for heart failure: 1W: 9.7% vs. 8W: 6.5%, P = 0.651). The risk within the 8W-group to fail full-recovery after 6 months tended to be lower. No patient in the study needed heart transplantation, LV assist device or died.
Bromocriptine treatment was associated with high rate of full LV-recovery and low morbidity and mortality in PPCM patients compared with other PPCM cohorts not treated with bromocriptine. No significant differences were observed between 1W and 8W treatment suggesting that 1-week addition of bromocriptine to standard heart failure treatment is already beneficial with a trend for better full-recovery in the 8W group.
ClinicalTrials.gov, study number: NCT00998556.
Abstract
Aims
Small-interfering RNA (siRNA)-based targeting of proprotein convertase subtilisin/kexin type 9 (PCSK9) represents a novel therapeutic approach that may provide a convenient, ...infrequent, and safe dosing schedule to robustly lower low-density lipoprotein cholesterol (LDL-C). Given the long duration of action, however, establishing safety in particular with respect to immunogenicity is of paramount importance. In earlier clinical studies of other RNA-targeted treatment approaches (antisense oligonucleotide therapy) immunological and haematological adverse effects, in particular thrombocytopenia and pro-inflammatory effects, have been reported. Here, we present the pre-specified safety analysis from ORION-1 evaluating platelets, immune cells, immunological markers, antidrug antibodies, and clinical immunogenicity adverse events (AEs) under PCSK9 siRNA treatment with inclisiran.
Methods and results
The pre-specified safety analysis from ORION-1 was performed in six different inclisiran dosing regimens in patients at high risk of cardiovascular disease with elevated LDL-C levels. Patients received either a single dose (SD: 200 mg, n = 60; 300 mg, n = 62 or 500 mg, n = 66) or double-dose starting regimen (DD: 100 mg, n = 62; 200 mg, n = 63; or 300 mg, n = 61 on days 1 and 90) of inclisiran or placebo (SD: n = 65; DD: n = 62). The effects of inclisiran on haematological parameters including platelet counts, lymphocytes, and monocytes as well as on the immune markers interleukin 6 (IL-6) and tumour necrosis factor-α (TNF-α) were examined after 180 days. Immunogenicity was further evaluated by analysis of anti-drug-antibodies (ADAs) towards inclisiran in 6068 study samples and by careful analysis of immunogenicity AEs as part of the pharmacovigilance strategy. At day 180, no significant alterations of platelet counts were observed in any of the dosing groups (change from baseline, SD: 200 mg: 0.8%; 300 mg: −0.5%; 500 mg: −1.8%; DD: 100 mg: 1.3%; 200 mg: −0.5%; 300 mg: 1.0%; no significant difference for any group as compared with placebo). No significant effects on other immune cells, including leucocytes, monocytes, or neutrophils were detected. Notably, no significant increase of inflammatory biomarkers (IL-6 or TNF-α) with either the SD or DD regimen became evident. There was no evidence for immunogenicity based on ADA level analysis and careful review of clinical immunogenicity AEs in none of the treatment regimens.
Conclusion
In this pre-specified safety analysis of ORION-1 for the siRNA therapeutic inclisiran, no adverse effects on measures of inflammation or immune activation nor adverse effects on platelets or clinical immunogenicity AEs were observed over at least 6-month treatment. These safety findings in the largest analysis of an RNAi study in humans to date provide strong reassurance about the safety of inclisiran and the potential of cardiovascular RNA-targeted therapies.
Peripartum cardiomyopathy (PPCM) is a life-threatening pregnancy-associated cardiomyopathy in previously healthy women. Although PPCM is driven in part by the 16-kDa N-terminal prolactin fragment ...(16K PRL), the underlying molecular mechanisms are poorly understood. We found that 16K PRL induced microRNA-146a (miR-146a) expression in ECs, which attenuated angiogenesis through downregulation of NRAS. 16K PRL stimulated the release of miR-146a-loaded exosomes from ECs. The exosomes were absorbed by cardiomyocytes, increasing miR-146a levels, which resulted in a subsequent decrease in metabolic activity and decreased expression of Erbb4, Notch1, and Irak1. Mice with cardiomyocyte-restricted Stat3 knockout (CKO mice) exhibited a PPCM-like phenotype and displayed increased cardiac miR-146a expression with coincident downregulation of Erbb4, Nras, Notch1, and Irak1. Blocking miR-146a with locked nucleic acids or antago-miRs attenuated PPCM in CKO mice without interrupting full-length prolactin signaling, as indicated by normal nursing activities. Finally, miR-146a was elevated in the plasma and hearts of PPCM patients, but not in patients with dilated cardiomyopathy. These results demonstrate that miR-146a is a downstream-mediator of 16K PRL that could potentially serve as a biomarker and therapeutic target for PPCM.
Abstract
Aims
Inflammation is a key driver of atherosclerosis and myocardial infarction (MI), and beyond proteins and microRNAs (miRs), long noncoding RNAs (lncRNAs) have been implicated in ...inflammation control. To obtain further information on the possible role of lncRNAs in the context of atherosclerosis, we obtained comprehensive transcriptome maps of circulating immune cells (peripheral blood mononuclear cells, PBMCs) of early onset MI patients. One lncRNA significantly suppressed in post-MI patients was further investigated in a murine knockout model.
Methods and results
Individual RNA-sequencing (RNA-seq) was conducted on PBMCs from 28 post-MI patients with a history of MI at age ≤50 years and stable disease ≥3 months before study participation, and from 31 healthy individuals without manifest cardiovascular disease or family history of MI as controls. RNA-seq revealed deregulated protein-coding transcripts and lncRNAs in post-MI PBMCs, among which nuclear enriched abundant transcript (NEAT1) was the most highly expressed lncRNA, and the only one significantly suppressed in patients. Multivariate statistical analysis of validation cohorts of 106 post-MI patients and 85 controls indicated that the PBMC NEAT1 levels were influenced (P = 0.001) by post-MI status independent of statin intake, left ventricular ejection fraction, low-density lipoprotein or high-density lipoprotein cholesterol, or age. We investigated NEAT1−/− mice as a model of NEAT1 deficiency to evaluate if NEAT1 depletion may directly and causally alter immune regulation. RNA-seq of NEAT1−/− splenocytes identified disturbed expression and regulation of chemokines/receptors, innate immunity genes, tumour necrosis factor (TNF) and caspases, and increased production of reactive oxygen species (ROS) under baseline conditions. NEAT1−/− spleen displayed anomalous Treg and TH cell differentiation. NEAT1−/− bone marrow-derived macrophages (BMDMs) displayed altered transcriptomes with disturbed chemokine/chemokine receptor expression, increased baseline phagocytosis (P < 0.0001), and attenuated proliferation (P = 0.0013). NEAT1−/− BMDMs responded to LPS with increased (P < 0.0001) ROS production and disturbed phagocytic activity (P = 0.0318). Monocyte-macrophage differentiation was deregulated in NEAT1−/− bone marrow and blood. NEAT1−/− mice displayed aortic wall CD68+ cell infiltration, and there was evidence of myocardial inflammation which could lead to severe and potentially life-threatening structural damage in some of these animals.
Conclusion
The study indicates distinctive alterations of lncRNA expression in post-MI patient PBMCs. Regarding the monocyte-enriched NEAT1 suppressed in post-MI patients, the data from NEAT1−/− mice identify NEAT1 as a novel lncRNA-type immunoregulator affecting monocyte-macrophage functions and T cell differentiation. NEAT1 is part of a molecular circuit also involving several chemokines and interleukins persistently deregulated post-MI. Individual profiling of this circuit may contribute to identify high-risk patients likely to benefit from immunomodulatory therapies. It also appears reasonable to look for new therapeutic targets within this circuit.
Gut microbiota and their generated metabolites impact the host vascular phenotype. The metaorganismal metabolite trimethylamine N-oxide (TMAO) is both associated with adverse clinical thromboembolic ...events, and enhances platelet responsiveness in subjects. The impact of TMAO on vascular Tissue Factor (TF) in vivo is unknown. Here, we explore whether TMAO-enhanced thrombosis potential extends beyond TMAO effects on platelets, and is linked to TF. We also further explore the links between gut microbiota and vascular endothelial TF expression in vivo.
In initial exploratory clinical studies, we observed that among sequential stable subjects (n = 2989) on anti-platelet therapy undergoing elective diagnostic cardiovascular evaluation at a single-site referral centre, TMAO levels were associated with an increased incident (3 years) risk for major adverse cardiovascular events (MACE) (myocardial infarction, stroke, or death) 4th quartile (Q4) vs. Q1 adjusted hazard ratio (HR) 95% confidence interval (95% CI), 1.73 (1.25-2.38). Similar results were observed within subjects on aspirin mono-therapy during follow-up adjusted HR (95% CI) 1.75 (1.25-2.44), n = 2793. Leveraging access to a second higher risk cohort with previously reported TMAO data and monitoring of anti-platelet medication use, we also observed a strong association between TMAO and incident (1 year) MACE risk in the multi-site Swiss Acute Coronary Syndromes Cohort, focusing on the subset (n = 1469) on chronic dual anti-platelet therapy during follow-up adjusted HR (95% CI) 1.70 (1.08-2.69). These collective clinical data suggest that the thrombosis-associated effects of TMAO may be mediated by cells/factors that are not inhibited by anti-platelet therapy. To test this, we first observed in human microvascular endothelial cells that TMAO dose-dependently induced expression of TF and vascular cell adhesion molecule (VCAM)1. In mouse studies, we observed that TMAO-enhanced aortic TF and VCAM1 mRNA and protein expression, which upon immunolocalization studies, was shown to co-localize with vascular endothelial cells. Finally, in arterial injury mouse models, TMAO-dependent enhancement of in vivo TF expression and thrombogenicity were abrogated by either a TF-inhibitory antibody or a mechanism-based microbial choline TMA-lyase inhibitor (fluoromethylcholine).
Endothelial TF contributes to TMAO-related arterial thrombosis potential, and can be specifically blocked by targeted non-lethal inhibition of gut microbial choline TMA-lyase.
Atherosclerosis is one of the leading causes of death worldwide. Biomathematical modelling of the underlying disease and therapy processes might be a useful aid to develop and improve preventive and ...treatment concepts of atherosclerosis. We here propose a biomathematical model of murine atherosclerosis under different diet and treatment conditions including lipid modulating compound and antibiotics. The model is derived by translating known biological mechanisms into ordinary differential equations and by assuming appropriate response kinetics to the applied interventions. We explicitly describe the dynamics of relevant immune cells and lipid species in atherosclerotic lesions including the degree of blood vessel occlusion due to growing plaques. Unknown model parameters were determined by fitting the predictions of model simulations to time series data derived from mice experiments. Parameter fittings resulted in a good agreement of model and data for all 13 experimental scenarios considered. The model can be used to predict the outcome of alternative treatment schedules of combined antibiotic, immune modulating, and lipid lowering agents under high fat or normal diet. We conclude that we established a comprehensive biomathematical model of atherosclerosis in mice. We aim to validate the model on the basis of further experimental data.
Symptoms of cancer cachexia (CC) include fatigue, shortness of breath, and impaired exercise capacity, which are also hallmark symptoms of heart failure (HF). Herein, we evaluate the effects of drugs ...commonly used to treat HF (bisoprolol, imidapril, spironolactone) on development of cardiac wasting, HF, and death in the rat hepatoma CC model (AH-130).
Tumour-bearing rats showed a progressive loss of body weight and left-ventricular (LV) mass that was associated with a progressive deterioration in cardiac function. Strikingly, bisoprolol and spironolactone significantly reduced wasting of LV mass, attenuated cardiac dysfunction, and improved survival. In contrast, imidapril had no beneficial effect. Several key anabolic and catabolic pathways were dysregulated in the cachectic hearts and, in addition, we found enhanced fibrosis that was corrected by treatment with spironolactone. Finally, we found cardiac wasting and fibrotic remodelling in patients who died as a result of CC. In living cancer patients, with and without cachexia, serum levels of brain natriuretic peptide and aldosterone were elevated.
Systemic effects of tumours lead not only to CC but also to cardiac wasting, associated with LV-dysfunction, fibrotic remodelling, and increased mortality. These adverse effects of the tumour on the heart and on survival can be mitigated by treatment with either the β-blocker bisoprolol or the aldosterone antagonist spironolactone. We suggest that clinical trials employing these agents be considered to attempt to limit this devastating complication of cancer.
Purpose
The chemokine receptor CXCR4 is a promising target for molecular imaging of CXCR4
+
cell types, e.g. inflammatory cells, in cardiovascular diseases. We speculated that a specific CXCR4 ...ligand,
68
Gapentixafor, along with novel techniques for motion correction, would facilitate the in vivo characterization of CXCR4 expression in small culprit and nonculprit coronary atherosclerotic lesions after acute myocardial infarction by motion-corrected targeted PET/CT.
Methods
CXCR4 expression was analysed ex vivo in separately obtained arterial wall specimens.
68
GaPentixafor PET/CT was performed in 37 patients after stent-based reperfusion for a first acute ST-segment elevation myocardial infarction. List-mode PET data were reconstructed to five different datasets using cardiac and/or respiratory gating. Guided by CT for localization, the PET signals of culprit and various groups of nonculprit coronary lesions were analysed and compared.
Results
Ex vivo, CXCR4 was upregulated in atherosclerotic lesions, and mainly colocalized with CD68
+
inflammatory cells. In vivo, elevated CXCR4 expression was detected in culprit and nonculprit lesions, and the strongest CXCR4 PET signal (median SUV
max
1.96; interquartile range, IQR, 1.55–2.31) was observed in culprit coronary artery lesions. Stented nonculprit lesions (median SUV
max
1.45, IQR 1.23–1.88;
P
= 0.048) and hot spots in naive remote coronary segments (median SUV
max
1.34, IQR 1.23–1.74;
P
= 0.0005) showed significantly lower levels of CXCR4 expression. Dual cardiac/respiratory gating provided the strongest CXCR4 PET signal and the highest lesion detectability.
Conclusion
We demonstrated the basic feasibility of motion-corrected targeted PET/CT imaging of CXCR4 expression in coronary artery lesions, which was triggered by vessel wall inflammation but also by stent-induced injury. This novel methodology may serve as a platform for future diagnostic and therapeutic clinical studies targeting the biology of coronary atherosclerotic plaque.
Immune Mechanisms of Plaque Instability Gerhardt, Teresa; Haghikia, Arash; Stapmanns, Philip ...
Frontiers in cardiovascular medicine,
01/2022, Letnik:
8
Journal Article
Recenzirano
Odprti dostop
Inflammation crucially drives atherosclerosis from disease initiation to the emergence of clinical complications. Targeting pivotal inflammatory pathways without compromising the host defense could ...compliment therapy with lipid-lowering agents, anti-hypertensive treatment, and lifestyle interventions to address the substantial residual cardiovascular risk that remains beyond classical risk factor control. Detailed understanding of the intricate immune mechanisms that propel plaque instability and disruption is indispensable for the development of novel therapeutic concepts. In this review, we provide an overview on the role of key immune cells in plaque inception and progression, and discuss recently identified maladaptive immune phenomena that contribute to plaque destabilization, including epigenetically programmed trained immunity in myeloid cells, pathogenic conversion of autoreactive regulatory T-cells and expansion of altered leukocytes due to clonal hematopoiesis. From a more global perspective, the article discusses how systemic crises such as acute mental stress or infection abruptly raise plaque vulnerability and summarizes recent advances in understanding the increased cardiovascular risk associated with COVID-19 disease. Stepping outside the box, we highlight the role of gut dysbiosis in atherosclerosis progression and plaque vulnerability. The emerging differential role of the immune system in plaque rupture and plaque erosion as well as the limitations of animal models in studying plaque disruption are reviewed.
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