Basic Research in Cardiology最新文献

Decreased nicotinamide adenine dinucleotide (NAD⁺) levels contribute to various pathologies such as ageing, diabetes, heart failure and ischemia-reperfusion injury (IRI). Nicotinamide riboside (NR) has emerged as a promising therapeutic NAD⁺ precursor due to efficient NAD⁺ elevation and was recently shown to be the only agent able to reduce cardiac IRI in models employing clinically relevant anesthesia. However, through which metabolic pathway(s) NR mediates IRI protection remains unknown. Furthermore, the influence of insulin, a known modulator of cardioprotective efficacy, on the protective effects of NR has not been investigated. Here, we used the isolated mouse heart allowing cardiac metabolic control to investigate: (1) whether NR can protect the isolated heart against IRI, (2) the metabolic pathways underlying NR-mediated protection, and (3) whether insulin abrogates NR protection. NR protection against cardiac IRI and effects on metabolic pathways employing metabolomics for determination of changes in metabolic intermediates, and ¹³C-glucose fluxomics for determination of metabolic pathway activities (glycolysis, pentose phosphate pathway (PPP) and mitochondrial/tricarboxylic acid cycle (TCA cycle) activities), were examined in isolated C57BL/6N mouse hearts perfused with either (a) glucose + fatty acids (FA) ("mild glycolysis group"), (b) lactate + pyruvate + FA ("no glycolysis group"), or (c) glucose + FA + insulin ("high glycolysis group"). NR increased cardiac NAD⁺ in all three metabolic groups. In glucose + FA perfused hearts, NR reduced IR injury, increased glycolytic intermediate phosphoenolpyruvate (PEP), TCA intermediate succinate and PPP intermediates ribose-5P (R5P) / sedoheptulose-7P (S7P), and was associated with activated glycolysis, without changes in TCA cycle or PPP activities. In the "no glycolysis" hearts, NR protection was lost, whereas NR still increased S7P. In the insulin hearts, glycolysis was largely accelerated, and NR protection abrogated. NR still increased PPP intermediates, with now high ¹³C-labeling of S7P, but NR was unable to increase metabolic pathway activities, including glycolysis. Protection by NR against IRI is only present in hearts with low glycolysis, and is associated with activation of glycolysis. When activation of glycolysis was prevented, through either examining "no glycolysis" hearts or "high glycolysis" hearts, NR protection was abolished. The data suggest that NR's acute cardioprotective effects are mediated through glycolysis activation and are lost in the presence of insulin because of already elevated glycolysis.

Right ventricular (RV) failure remains the strongest determinant of survival in pulmonary hypertension (PH). We aimed to identify relevant mechanisms, beyond pressure overload, associated with maladaptive RV hypertrophy in PH. To separate the effect of pressure overload from other potential mechanisms, we developed in pigs two experimental models of PH (M1, by pulmonary vein banding and M2, by aorto-pulmonary shunting) and compared them with a model of pure pressure overload (M3, pulmonary artery banding) and a sham-operated group. Animals were assessed at 1 and 8 months by right heart catheterization, cardiac magnetic resonance and blood sampling, and myocardial tissue was analyzed. Plasma unbiased proteomic and metabolomic data were compared among groups and integrated by an interaction network analysis. A total of 33 pigs completed follow-up (M1, n = 8; M2, n = 6; M3, n = 10; and M0, n = 9). M1 and M2 animals developed PH and reduced RV systolic function, whereas animals in M3 showed increased RV systolic pressure but maintained normal function. Significant plasma arginine and histidine deficiency and complement system activation were observed in both PH models (M1&M2), with additional alterations to taurine and purine pathways in M2. Changes in lipid metabolism were very remarkable, particularly the elevation of free fatty acids in M2. In the integrative analysis, arginine-histidine-purines deficiency, complement activation, and fatty acid accumulation were significantly associated with maladaptive RV hypertrophy. Our study integrating imaging and omics in large-animal experimental models demonstrates that, beyond pressure overload, metabolic alterations play a relevant role in RV dysfunction in PH.

Multiple common cardiovascular comorbidities produce coronary microvascular dysfunction. We previously observed in swine that a combination of diabetes mellitus (DM), high fat diet (HFD) and chronic kidney disease (CKD) induced systemic inflammation, increased oxidative stress and produced coronary endothelial dysfunction, altering control of coronary microvascular tone via loss of NO bioavailability, which was associated with an increase in circulating endothelin (ET). In the present study, we tested the hypotheses that (1) ROS scavenging and (2) ET_A+B-receptor blockade improve myocardial oxygen delivery in the same female swine model. Healthy female swine on normal pig chow served as controls (Normal). Five months after induction of DM (streptozotocin, 3 × 50 mg kg⁻¹ i.v.), hypercholesterolemia (HFD) and CKD (renal embolization), swine were chronically instrumented and studied at rest and during exercise. Sustained hyperglycemia, hypercholesterolemia and renal dysfunction were accompanied by systemic inflammation and oxidative stress. In vivo ROS scavenging (TEMPOL + MPG) reduced myocardial oxygen delivery in DM + HFD + CKD swine, suggestive of a vasodilator influence of endogenous ROS, while it had no effect in Normal swine. In vitro wire myography revealed a vasodilator role for hydrogen peroxide (H₂O₂) in isolated small coronary artery segments from DM + HFD + CKD, but not Normal swine. Increased catalase activity and ceramide production in left ventricular myocardial tissue of DM + HFD + CKD swine further suggest that increased H₂O₂ acts as vasodilator ROS in the coronary microvasculature. Despite elevated ET-1 plasma levels in DM + HFD + CKD swine, ET_A+B blockade did not affect myocardial oxygen delivery in Normal or DM + HFD + CKD swine. In conclusion, loss of NO bioavailability due to 5 months exposure to multiple comorbidities is partially compensated by increased H₂O₂-mediated coronary vasodilation.

The right ventricle (RV) differs developmentally, anatomically and functionally from the left ventricle (LV). Therefore, characteristics of LV adaptation to chronic pressure overload cannot easily be extrapolated to the RV. Mitochondrial abnormalities are considered a crucial contributor in heart failure (HF), but have never been compared directly between RV and LV tissues and cardiomyocytes. To identify ventricle-specific mitochondrial molecular and functional signatures, we established rat models with two slowly developing disease stages (compensated and decompensated) in response to pulmonary artery banding (PAB) or ascending aortic banding (AOB). Genome-wide transcriptomic and proteomic analyses were used to identify differentially expressed mitochondrial genes and proteins and were accompanied by a detailed characterization of mitochondrial function and morphology. Two clearly distinguishable disease stages, which culminated in a comparable systolic impairment of the respective ventricle, were observed. Mitochondrial respiration was similarly impaired at the decompensated stage, while respiratory chain activity or mitochondrial biogenesis were more severely deteriorated in the failing LV. Bioinformatics analyses of the RNA-seq. and proteomic data sets identified specifically deregulated mitochondrial components and pathways. Although the top regulated mitochondrial genes and proteins differed between the RV and LV, the overall changes in tissue and cardiomyocyte gene expression were highly similar. In conclusion, mitochondrial dysfuntion contributes to disease progression in right and left heart failure. Ventricle-specific differences in mitochondrial gene and protein expression are mostly related to the extent of observed changes, suggesting that despite developmental, anatomical and functional differences mitochondrial adaptations to chronic pressure overload are comparable in both ventricles.

Ascending thoracic aortic aneurysm (ATAA) remains a significant medical concern, with its asymptomatic nature posing diagnostic and monitoring challenges, thereby increasing the risk of aortic wall dissection and rupture. Current management of aortic repair relies on an aortic diameter threshold. However, this approach underestimates the complexity of aortic wall disease due to important knowledge gaps in understanding its underlying pathologic mechanisms.

Since traditional risk factors cannot explain the initiation and progression of ATAA leading to dissection, local vascular factors such as extracellular matrix (ECM) and vascular smooth muscle cells (VSMCs) might harbor targets for early diagnosis and intervention. Derived from diverse embryonic lineages, VSMCs exhibit varied responses to genetic abnormalities that regulate their contractility. The transition of VSMCs into different phenotypes is an adaptive response to stress stimuli such as hemodynamic changes resulting from cardiovascular disease, aging, lifestyle, and genetic predisposition. Upon longer exposure to stress stimuli, VSMC phenotypic switching can instigate pathologic remodeling that contributes to the pathogenesis of ATAA.

This review aims to illuminate the current understanding of cellular and molecular characteristics associated with ATAA and dissection, emphasizing the need for a more nuanced comprehension of the impaired ECM–VSMC network.

Heart failure continues to be a significant global health concern, causing substantial morbidity and mortality. The limited ability of the adult heart to regenerate has posed challenges in finding effective treatments for cardiac pathologies. While various medications and surgical interventions have been used to improve cardiac function, they are not able to address the extensive loss of functioning cardiomyocytes that occurs during cardiac injury. As a result, there is growing interest in understanding how the cell cycle is regulated and exploring the potential for stimulating cardiomyocyte proliferation as a means of promoting heart regeneration. This review aims to provide an overview of current knowledge on cell cycle regulation and mechanisms underlying cardiomyocyte proliferation in cases of heart failure, while also highlighting established and novel therapeutic strategies targeting this area for treatment purposes.

The present analysis reports on the robustness of preclinical cardioprotection studies with infarct size as endpoint which were published in Basic Research in Cardiology, Cardiovascular Research, and Circulation Research between January 2013 and December 2023. Only 26 out of 269 papers with technically robust analysis of infarct size by triphenyltetrazolium chloride staining, magnetic resonance imaging or single photon emission tomography applied a prospective power analysis. A retrospective power calculation revealed that only 75% of the reported data sets with statistically significant positive results from all these studies had a statistical power of ≥ 0.9, and an additional 9% had a statistical power ≥ 0.8. The remaining 16% of all significant positive data sets did not even reach the 0.8 threshold. Only 13% of all analyzed data sets were neutral. We conclude that neutral studies are underreported and there is indeed a significant lack of robustness in many of the published preclinical cardioprotection studies which may contribute to the difficulties of translating cardioprotection to patient benefit.

Hypertrophic cardiomyopathy (HCM) constitutes the most common genetic cardiac disorder. However, current pharmacotherapeutics are mainly symptomatic and only partially address underlying molecular mechanisms. Circular RNAs (circRNAs) are a recently discovered class of non-coding RNAs and emerged as specific and powerful regulators of cellular functions. By performing global circRNA-specific next generation sequencing in cardiac tissue of patients with hypertrophic cardiomyopathy compared to healthy donors, we identified circZFPM2 (hsa_circ_0003380). CircZFPM2, which derives from the ZFPM2 gene locus, is a highly conserved regulatory circRNA that is strongly induced in HCM tissue. In vitro loss-of-function experiments were performed in neonatal rat cardiomyocytes, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), and HCM-patient-derived hiPSC-CMs. A knockdown of circZFPM2 was found to induce cardiomyocyte hypertrophy and compromise mitochondrial respiration, leading to an increased production of reactive oxygen species and apoptosis. In contrast, delivery of recombinant circZFPM2, packaged in lipid-nanoparticles or using AAV-based overexpression, rescued cardiomyocyte hypertrophic gene expression and promoted cell survival. Additionally, HCM-derived cardiac organoids exhibited improved contractility upon CM-specific overexpression of circZFPM2. Multi-Omics analysis further promoted our hypothesis, showing beneficial effects of circZFPM2 on cardiac contractility and mitochondrial function. Collectively, our data highlight that circZFPM2 serves as a promising target for the treatment of cardiac hypertrophy including HCM.

Lysophosphatidic acid (LPA) is a bioactive phospholipid that plays a crucial role in cardiovascular diseases. Here, we question whether LPA contributes to myocardial ischemia/reperfusion (I/R) injury by acting on transient receptor potential vanilloid 1 (TRPV1) in spinal cord. By ligating the left coronary artery to establish an in vivo I/R mouse model, we observed a 1.57-fold increase in LPA level in the cerebrospinal fluid (CSF). The I/R-elevated CSF LPA levels were reduced by HA130, an LPA synthesis inhibitor, compared to vehicle treatment (4.74 ± 0.34 vs. 6.46 ± 0.94 μg/mL, p = 0.0014). Myocardial infarct size was reduced by HA130 treatment compared to the vehicle group (26 ± 8% vs. 46 ± 8%, p = 0.0001). To block the interaction of LPA with TRPV1 at the K710 site, we generated a K710N knock-in mouse model. The TRPV1^K710N mice were resistant to LPA-induced myocardial injury, showing a smaller infarct size relative to TRPV1^WT mice (28 ± 4% vs. 60 ± 7%, p < 0.0001). Additionally, a sequence-specific TRPV1 peptide targeting the K710 region produced similar protective effects against LPA-induced myocardial injury. Blocking the K710 region through K710N mutation or TRPV1 peptide resulted in reduced neuropeptides release and decreased activity of cardiac sensory neurons, leading to a decrease in cardiac norepinephrine concentration and the restoration of intramyocardial pro-survival signaling, namely protein kinase B/extracellular regulated kinase/glycogen synthase kinase-3β pathway. These findings suggest that the elevation of CSF LPA is strongly associated with myocardial I/R injury. Moreover, inhibiting the interaction of LPA with TRPV1 by blocking the K710 region uncovers a novel strategy for preventing myocardial ischemic injury.

The rupture of an atherosclerotic plaque cap overlying a lipid pool and/or necrotic core can lead to thrombotic cardiovascular events. In essence, the rupture of the plaque cap is a mechanical event, which occurs when the local stress exceeds the local tissue strength. However, due to inter- and intra-cap heterogeneity, the resulting ultimate cap strength varies, causing proper assessment of the plaque at risk of rupture to be lacking. Important players involved in tissue strength include the load-bearing collagenous matrix, macrophages, as major promoters of extracellular matrix degradation, and microcalcifications, deposits that can exacerbate local stress, increasing tissue propensity for rupture. This review summarizes the role of these components individually in tissue mechanics, along with the interplay between them. We argue that to be able to improve risk assessment, a better understanding of the effect of these individual components, as well as their reciprocal relationships on cap mechanics, is required. Finally, we discuss potential future steps, including a holistic multidisciplinary approach, multifactorial 3D in vitro model systems, and advancements in imaging techniques. The obtained knowledge will ultimately serve as input to help diagnose, prevent, and treat atherosclerotic cap rupture.