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Interleukin-1β (IL-1β) is a key mediator of non-alcoholic steatohepatitis (NASH), a chronic liver disease, and of systemic inflammation-driven aging. IL-1β contributes to cardio-metabolic decline, and may promote hepatic oncogenic transformation. Therefore, IL-1β is a potential therapeutic target in these pathologies. We aimed to investigate the hepatic and cardiac effects of an IL-1β targeting monoclonal antibody in an aged mouse model of NASH. 24 months old male C57Bl/6J mice were fed with control or choline deficient (CDAA) diet and were treated with isotype control or anti-IL-1β Mab for 8 weeks. Cardiac functions were assessed by conventional—and 2D speckle tracking echocardiography. Liver samples were analyzed by immunohistochemistry and qRT-PCR. Echocardiography revealed improved cardiac diastolic function in anti-IL-1β treated mice with NASH. Marked hepatic fibrosis developed in CDAA-fed group, but IL-1β inhibition affected fibrosis only at transcriptomic level. Hepatic inflammation was not affected by the IL-1β inhibitor. PCNA staining revealed intensive hepatocyte proliferation in CDAA-fed animals, which was not influenced by neutralization of IL-1β. IL-1β inhibition increased hepatic expression of Pd-1 and Ctla4 , while Pd-l1 expression increased in NASH. In conclusion, IL-1β inhibition improved cardiac diastolic function, but did not ameliorate features of NASH; moreover, even promoted hepatic immune checkpoint expression, with concomitant NASH-related hepatocellular proliferation.

Background Incretin analogues, used for the treatment of type 2 diabetes mellitus and obesity, such as GLP1-receptor agonist liraglutide (Lira) have been shown to reduce major adverse cardiac events in recent clinical trials of heart failure. Tirzepatide (TZP), a dual GIP/GLP1-receptor agonist has shown promising results in the SUMMIT trial as improved cardiovascular outcomes in patients with heart failure with preserved ejection fraction (HFpEF). However, data regarding their use in heart failure with reduced ejection fraction (HFrEF) is lacking. We performed a head-to-head comparative study in a mouse model of non-ischaemic cardiac injury induced by continuous angiotensin II (AngII) infusion, as AngII is a key driver of both heart failure forms. Methods Osmotic minipumps were inserted for subcutaneous (s.c.) administration of AngII (1.5 mg/kg/day) in 5-month-old male Balb/c mice or sham surgery was performed. Animals were treated with vehicle (Veh), Lira (300 µg/day i.p.) or TZP (48 µg/day s.c.) for 14 days in the following groups: Sham/Veh (n = 7), AngII/Veh (n = 15), Sham/Lira (n = 7), AngII/Lira (n = 15), Sham/TZP (n = 8), AngII/TZP (n = 15). Cardiac structural, functional and molecular characteristics were assessed by echocardiography, ECG, immunohistochemistry, flow cytometry and qRT-PCR. Results Mortality was significantly higher in AngII/Veh animals compared to controls, while AngII/TZP mice showed significantly reduced mortality after 14 days of treatment. Both Lira and TZP caused significant weight reduction compared to controls. AngII given alone also reduced body mass, and this reduction was further enhanced by TZP. Treatment with both compounds preserved cardiac systolic and diastolic function compared with AngII/Veh animals, as shown by normal ejection fraction and E/e’, respectively. Both Lira and TZP decreased the AngII-induced elevation of cardiac fibrosis and hypertrophy markers, including Ctgf, Col1a1, Col3a1, and Nppa, while TZP also reduced the elevated Nppb level. TZP also reduced systemic inflammation, as shown by the reduction in serum CRP levels. Conclusions Lira and TZP preserved cardiac function and decreased markers of hypertrophy and fibrosis in mice with AngII-induced heart failure, whereas TZP also significantly decreased mortality. In addition to HFpEF, the use of incretin analogues may also be of clinical relevance in the treatment of HFrEF. However, as patients with heart failure, AngII level is elevated and can cause weight loss/cachexia, the usage of incretin analogues to treat non-obese heart failure patients should be considered. Graphical abstract

Hypercholesterolemia (HC) induces, propagates and exacerbates cardiovascular diseases via various mechanisms that are yet not properly understood. Extracellular vesicles (EVs) are involved in the pathomechanism of these diseases. To understand how circulating or cardiac-derived EVs could affect myocardial functions, we analyzed the metabolomic profile of circulating EVs, and we performed an in-depth analysis of cardiomyocyte (CM)-derived EVs in HC. Circulating EVs were isolated with Vezics technology from male Wistar rats fed with high-cholesterol or control chow. AC16 human CMs were treated with Remembrane HC supplement and EVs were isolated from cell culture supernatant. The biophysical properties and the protein composition of CM EVs were analyzed. THP1-ASC-GFP cells were treated with CM EVs, and monocyte activation was measured. HC diet reduced the amount of certain phosphatidylcholines in circulating EVs, independently of their plasma level. HC treatment significantly increased EV secretion of CMs and greatly modified CM EV proteome, enriching several proteins involved in tissue remodeling. Regardless of the treatment, CM EVs did not induce the activation of THP1 monocytes. In conclusion, HC strongly affects the metabolome of circulating EVs and dysregulates CM EVs, which might contribute to HC-induced cardiac derangements.

Aims The association and co-isolation of low-density lipoproteins (LDL) and extracellular vesicles (EVs) have been shown in blood plasma. Here we explore this relationship to better understand the role of EVs in atherogenesis. Methods and results Wild type (WT), PCSK9 −/− , and LDLR −/− C57BL/6 mice were used in this study. Eleven week-old male mice were fed high-fat diet (HFD) for 12 weeks or kept on normal diet until old age (22-months). Cardiac function was assessed by ultrasound, cholesterol was quantified with a colorimetric kit and circulating EVs were measured using flow cytometry. Plaques were analysed post-mortem using Oil-Red-O staining of the aortic arch. EVs were measured from platelet free blood plasma samples of normal and hypercholesterolaemic clinical patients. Based on annexin V and CD63 staining, we found a significant increase in EV levels in LDLR −/− and PCSK9 −/− mice after HFD, but CD81 showed no significant change in either group. There was no significant change in plaque formation after HFD. PCSK9 −/− mice show a favourable cardiac function after HFD. Blood cholesterol levels progressively increased during HFD, with LDLR −/− mice showing high levels while PCSK9 −/− were significantly lowered compared to WT animals. In mice at old age, similar cholesterol levels were observed as in young mice. In old age, LDLR −/− mice showed significantly increased plaques. At old age, ejection fraction was decreased in all groups of mice, as were CD63 + EVs. Similarly to mice, in patients with hypercholesterolaemia, CD63 + EVs were significantly depleted. Conclusions This research demonstrates an inverse relationship between circulating EVs and cholesterol, making EVs a potential marker for cardiovascular disease (CVD). HFD causes reduced cardiac function, but atherosclerotic development is slowly progressing in hypercholesterolaemic models and only observed with old animals. These results also bring further evidence for the benefit of using of PCSK9 inhibitors as therapeutic agents in CVD.

Despite accumulating data on underlying mechanisms, the influence of sex and prevalent cardio-metabolic co-morbidities on the manifestation and severity of immune checkpoint inhibitor (ICI)-induced cardiotoxicity has not been well defined. To elucidate whether sex and prevalent cardio-metabolic co-morbidities affect ICI-induced cardiotoxicity, we randomized 17-month-old male and female mice to receive control diet (CON) or high-fat diet (HFD) + L-NAME—a well-established mouse model of cardio-metabolic co-morbidities—for 17 weeks ( n  = 5–7), and evaluated markers of T-cell function in the spleen. As expected, HFD + L-NAME significantly increased body- and heart weight, and serum cholesterol levels, and caused no systolic dysfunction, however, led to diastolic dysfunction, cardiomyocyte hypertrophy, and increased fibrosis only in males compared to corresponding CON. Western blot analyses of splenic immune checkpoint protein levels showed differential expression depending on sex and prevalent cardio-metabolic co-morbidities, suggesting T-cell exhaustion in both sexes on HFD + L-NAME, but more pronounced in males. In a sub-study with a similar setup, we tested cardiotoxic manifestations of ICI by treating mice with anti-PD-1 monoclonal antibody (ICI) for the last 2 weeks of diet administration ( n  = 5–7). After 2 weeks of ICI treatment, cardiac systolic functions significantly decreased in CON, but not in HFD + L-NAME groups of both sexes compared to baseline (before ICI administration). In conclusion, in this exploratory study using aged mice, we describe for the first time that ICI-related systolic dysfunction is diminished in both sexes when obesity and hypercholesterolemia are present, possibly due to obesity-related T-cell exhaustion.

The identification of novel drug targets is needed to improve the outcomes of heart failure (HF). G-protein-coupled receptors (GPCRs) represent the largest family of targets for already approved drugs, thus providing an opportunity for drug repurposing. Here, we aimed (i) to investigate the differential expressions of 288 cardiac GPCRs via droplet digital PCR (ddPCR) and bulk RNA sequencing (RNAseq) in a rat model of left ventricular pressure-overload; (ii) to compare RNAseq findings with those of ddPCR; and (iii) to screen and test for novel, translatable GPCR drug targets in HF. Male Wistar rats subjected to transverse aortic constriction (TAC, n = 5) showed significant systolic dysfunction vs. sham operated animals (SHAM, n = 5) via echocardiography. In TAC vs. SHAM hearts, RNAseq identified 69, and ddPCR identified 27 significantly differentially expressed GPCR mRNAs, 8 of which were identified using both methods, thus showing a correlation between the two methods. Of these, Prostaglandin-F2α-receptor (Ptgfr) was further investigated and localized on cardiomyocytes and fibroblasts in murine hearts via RNA-Scope. Antagonizing Ptgfr via AL-8810 reverted angiotensin-II-induced cardiomyocyte hypertrophy in vitro. In conclusion, using ddPCR as a novel screening method, we were able to identify GPCR targets in HF. We also show that the antagonism of Ptgfr could be a novel target in HF by alleviating cardiomyocyte hypertrophy.

Aims Heart failure with reduced ejection fraction (HFrEF) is a leading cause of death worldwide; thus, therapeutic improvements are needed. In vivo preclinical models are essential to identify molecular drug targets for future therapies. Transverse aortic constriction (TAC) is a well‐established model of HFrEF; however, highly experienced personnel are needed for the surgery, and several weeks of follow‐up are necessary to develop HFrEF. To this end, we aimed (i) to develop an easy‐to‐perform mouse model of HFrEF by treating Balb/c mice with angiotensin‐II (Ang‐II) for 2 weeks by minipump and (ii) to compare its cardiac phenotype and transcriptome to the well‐established TAC model of HFrEF in C57BL/6J mice. Methods Mortality and gross pathological data, cardiac structural and functional characteristics assessed by echocardiography and immunohistochemistry and differential gene expression obtained by RNA‐sequencing and gene‐ontology analyses were used to characterize and compare the two models. To achieve statistical comparability between the two models, changes in treatment groups related to the corresponding control were compared (ΔTAC vs. ΔAng‐II). Results Compared with the well‐established TAC model, chronic Ang‐II treatment of Balb/c mice shares similarities in cardiac systolic functional decline (left ventricular ejection fraction: −57.25 ± 7.17% vs. −43.68 ± 5.31% in ΔTAC vs. ΔAng‐II; P = 0.1794) but shows a lesser degree of left ventricular dilation (left ventricular end‐systolic volume: 190.81 ± 44.13 vs. 57.37 ± 10.18 mL in ΔTAC vs. ΔAng‐II; P = 0.0252) and hypertrophy (cell surface area: 58.44 ± 6.1 vs. 10.24 ± 2.87 μm2 in ΔTAC vs. ΔAng‐II; P < 0.001); nevertheless, transcriptomic changes in the two HFrEF models show strong correlation (Spearman's r = 0.727; P < 0.001). In return, Ang‐II treatment in Balb/c mice needs significantly less procedural time [38 min, interquartile range (IQR): 31–46 min in TAC vs. 6 min, IQR: 6–7 min in Ang‐II; P < 0.001] and surgical expertise, is less of an object for peri‐procedural mortality (15.8% in TAC vs. 0% in Ang‐II; P = 0.105) and needs significantly shorter follow‐up for developing HFrEF. Conclusions Here, we demonstrate for the first time that chronic Ang‐II treatment of Balb/c mice is also a relevant, reliable but significantly easier‐to‐perform preclinical model to identify novel pathomechanisms and targets in future HFrEF research.

Clinical observations are highly inconsistent with the use of the antidiabetic rosiglitazone regarding its associated increased risk of myocardial infarction. This may be due to its hidden cardiotoxic properties that have only become evident during post-marketing studies. Therefore, we aimed to investigate the hidden cardiotoxicity of rosiglitazone in ischemia/reperfusion (I/R) injury models. Rats were treated orally with either 0.8 mg/kg/day rosiglitazone or vehicle for 28 days and subjected to I/R with or without cardioprotective ischemic preconditioning (IPC). Rosiglitazone did not affect mortality, arrhythmia score, or infarct size during I/R. However, rosiglitazone abolished the antiarrhythmic effects of IPC. To investigate the direct effect of rosiglitazone on cardiomyocytes, we utilized adult rat cardiomyocytes (ARCMs), AC16, and differentiated AC16 (diffAC16) human cardiac cell lines. These were subjected to simulated I/R in the presence of rosiglitazone. Rosiglitazone improved cell survival of ARCMs at 0.3 μM. At 0.1 and 0.3 μM, rosiglitazone improved cell survival of AC16s but not that of diffAC16s. This is the first demonstration that chronic administration of rosiglitazone does not result in major hidden cardiotoxic effects in myocardial I/R injury models. However, the inhibition of the antiarrhythmic effects of IPC may have some clinical relevance that needs to be further explored.

Background/Objectives: In heart failure (HF) with reduced ejection fraction (HFrEF), the early diagnosis and proper treatment of comorbidities (CMs) are of fundamental relevance. Our aim was to assess the prevalence of CMs among real-world patients requiring hospitalisation for HFrEF and to investigate the effect of CMs on the implementation of guideline-directed medical therapy (GDMT) and on all-cause mortality (ACM). Methods: The data of a consecutive HFrEF patient cohort hospitalised for HF between 2021 and 2024 were analysed retrospectively. Sixteen CMs (6 CV and 10 non-CV) were considered. Patients were divided into three categories: 0–3 vs. 4–6 vs. ≥7 CMs. GDMT at discharge and ACM were compared among CM categories. The predictors of 1-year ACM were also evaluated. Results: From the 388 patients (male: 76%, age: 61 [50–70] years; NT-proBNP: 5286 [2570–9923] pg/mL; ≥2 cardiovascular–kidney–metabolic disease overlap: 46%), a large proportion received GDMT (RASi: 91%; βB: 85%; MRA: 95%; SGLT2i: 59%; triple therapy [TT: RASi+βB+MRA]: 82%; quadruple therapy [QT: TT + SGLT2i]: 54%) at discharge. Multimorbidity was accompanied with a (p < 0.05) lower application ratio of RASi (96% vs. 92% vs. 85%; 0–3 vs. 4–6 vs. ≥7 CMs) and βB therapy (94% vs. 85% vs. 78%), while MRA (99% vs. 94% vs. 94%) and SGTL2i use (61% vs. 59% vs. 57%) did not differ (p > 0.05). Patients with multimorbidity were less likely to be treated with TT (93% vs. 82% vs. 73%, p = 0.001), while no difference was detected in the implementation of QT (56% vs. 54% vs. 50%, p = 0.685). The 1-year ACM of patients with an increased burden of CMs was higher (9% vs. 13% vs. 25%, p = 0.003). The risk of 1-year ACM was favourably affected by the use of TT/QT and less severe left ventricular systolic dysfunction, while having ≥5 CMs had an unfavourable impact on prognosis. Conclusions: According to our real-world analysis, HFrEF patients with an increased burden of CMs can expect a less favourable outcome. However, modern GDMT can even be applied in this patient population, resulting in a significantly improved prognosis. Thus, clinicians should insist on the early, conscious implementation of a prognosis-modifying drug regime in multimorbid HF patients as well.

Abstract Background Cardiac remodelling, a crucial aspect of heart failure, is commonly investigated in preclinical models by quantifying cardiomyocyte cross-sectional area (CSA) and microvascular density (MVD) via histological methods, such as immunohistochemistry. To achieve this, optimized protocols are needed, and the species specificity is dependent on the antibody used. Lectin histochemistry offers several advantages compared to antibody-based immunohistochemistry, including as cost-effectiveness and cross-species applicability. Direct comparisons between the two methods are lacking from the literature. Methods and results In this study, we compared antibody- and lectin-based methods for the histological assessment of cardiomyocyte CSA (with the use of anti-laminin and wheat germ agglutinin [WGA]) and microvascular density (utilizing anti-CD31 and isolectin B4 [ILB4]) using different embedding and antigen/carbohydrate retrieval techniques. Here, we describe a detailed, easy-to-use combined lectin histochemistry protocol (WGA and ILB4, ‘CardiLect’ protocol) for the histological assessment of cardiac remodelling. The lectin-based approach has been evaluated on a cross-species basis, and its efficacy has been demonstrated in zebrafish, rodents, large animals and human samples. We provide an ImageJ script (‘CardiLect Analyser’) for automated image analysis, validated in a preclinical heart failure model by correlating histological parameters with echocardiographic findings. CSA showed a significant positive correlation with left ventricular (LV) mass (P = 0.0098, rS = 0.7545) and significant negative correlation with markers of systolic function, such as ejection fraction (EF) (P = 0.0402, rS = −0.6364). Microvascular density showed significant negative correlation with LV mass (P = 0.0055, rS = −0.7622) and significant positive correlation with EF (P = 0.0106, rS = 0.7203). Conclusions The described combined lectin histochemistry protocol with the provided ImageJ script is an easy-to-use, cost-effective, cross-species approach for the histological assessment of cardiac remodelling.