Human cardiac fibroblasts isolated from patients with severe heart failure are immune-competent cells mediating an inflammatory response

Hypoxic-Normoxic Crosstalk Activates Pro-Inflammatory Signaling in Human Cardiac Fibroblasts and Myocytes in a Post-Infarct Myocardium on a Chip

Myocardial infarctions locally deprive myocardium of oxygenated blood and cause immediate cardiac myocyte necrosis. Irreparable myocardium is then replaced with a scar through a dynamic repair process that is an interplay between hypoxic cells of the infarct zone and normoxic cells of adjacent healthy myocardium. In many cases, unresolved inflammation or fibrosis occurs for reasons that are incompletely understood, increasing the risk of heart failure. Crosstalk between hypoxic and normoxic cardiac cells is hypothesized to regulate mechanisms of repair after a myocardial infarction. To test this hypothesis, microfluidic devices are fabricated on 3D printed templates for co-culturing hypoxic and normoxic cardiac cells. This system demonstrates that hypoxia drives human cardiac fibroblasts toward glycolysis and a pro-fibrotic phenotype, similar to the anti-inflammatory phase of wound healing. Co-culture with normoxic fibroblasts uniquely upregulates pro-inflammatory signaling in hypoxic fibroblasts, including increased secretion of tumor necrosis factor alpha (TNF-α). In co-culture with hypoxic fibroblasts, normoxic human induced pluripotent stem cell (hiPSC)-derived cardiac myocytes also increase pro-inflammatory signaling, including upregulation of interleukin 6 (IL-6) family signaling pathway and increased expression of IL-6 receptor. Together, these data suggest that crosstalk between hypoxic fibroblasts and normoxic cardiac cells uniquely activates phenotypes that resemble the initial pro-inflammatory phase of post-infarct wound healing.

Regional transcriptomic profiling reveals immune system enrichment in nonfailing atria and all chambers of the failing human heart

The different chambers of the human heart demonstrate regional physiological traits and may be differentially affected during pathological remodeling, resulting in heart failure. Few previous studies, however, have characterized the different chambers at a transcriptomic level. We, therefore, conducted whole tissue RNA sequencing and gene set enrichment analysis of biopsies collected from the four chambers of adult failing (n = 8) and nonfailing (n = 11) human hearts. Atria and ventricles demonstrated distinct transcriptional patterns. When compared with nonfailing ventricles, the transcriptional pattern of nonfailing atria was enriched for many gene sets associated with cardiogenesis, the immune system and bone morphogenetic protein (BMP), transforming growth factor-β (TGF-β), MAPK/JNK, and Wnt signaling. Differences between failing and nonfailing hearts were also determined. The transcriptional pattern of failing atria was distinct compared with that of nonfailing atria and enriched for gene sets associated with the innate and adaptive immune system, TGF-β/SMAD signaling, and changes in endothelial, smooth muscle cell, and cardiomyocyte physiology. Failing ventricles were also enriched for gene sets associated with the immune system. Based on the transcriptomic patterns, upstream regulators associated with heart failure were identified. These included many immune response factors predicted to be similarly activated for all chambers of failing hearts. In summary, the heart chambers demonstrate distinct transcriptional patterns that differ between failing and nonfailing hearts. Immune system signaling may be a hallmark of all four heart chambers in failing hearts and could constitute a novel therapeutic target.NEW & NOTEWORTHY The transcriptomic patterns of the four heart chambers were characterized in failing and nonfailing human hearts. Both nonfailing atria had distinct transcriptomic patterns characterized by cardiogenesis, the immune system and BMP/TGF-β, MAPK/JNK, and Wnt signaling. Failing atria and ventricles were enriched for gene sets associated with the innate and adaptive immune system. Key upstream regulators associated with heart failure were identified, including activated immune response elements, which may constitute novel therapeutic targets.

IL-1β-mediated adaptive reprogramming of endogenous human cardiac fibroblasts to cells with immune features during fibrotic remodeling

The source and roles of fibroblasts and T-cells during maladaptive remodeling and myocardial fibrosis in the setting of pulmonary arterial hypertension (PAH) have been long debated. We demonstrate, using single-cell mass cytometry, a subpopulation of endogenous human cardiac fibroblasts expressing increased levels of CD4, a helper T-cell marker, in addition to myofibroblast markers distributed in human fibrotic RV tissue, interstitial and perivascular lesions in SUGEN/Hypoxia (SuHx) rats, and fibroblasts labeled with pdgfrα CreERt2/+ in R26R-tdTomato mice. Recombinant IL-1β increases IL-1R, CCR2 receptor expression, modifies the secretome, and differentiates cardiac fibroblasts to form CD68-positive cell clusters. IL-1β also activates stemness markers, such as NANOG and SOX2, and genes involved in dedifferentiation, lymphoid cell function and metabolic reprogramming. IL-1β induction of lineage traced primary mouse cardiac fibroblasts causes these cells to lose their fibroblast identity and acquire an immune phenotype. Our results identify IL-1β induced immune-competency in human cardiac fibroblasts and suggest that fibroblast secretome modulation may constitute a therapeutic approach to PAH and other diseases typified by inflammation and fibrotic remodeling.

Literature Review: Pathophysiology of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction is a growing public health concern, a disease with poor health outcomes, and is showing increased prevalence globally. This review paper explores the literature with a focus on the pathophysiology and microbiology of preserved ejection fraction heart failure while drawing connections between preserved and reduced ejection fraction states. The discussion teases out the cellular level changes that affect the overall dysfunction of the cardiac tissue, including the clinical manifestations, microbiological changes (endothelial cells, fibroblasts, cardiomyocytes, and excitation-contraction coupling), and the burden of structural diastolic dysfunction. The goal of this review is to summarize the pathophysiological disease state of heart failure with preserved ejection fraction to enhance understanding, knowledge, current treatment models of this pathology.

Human cardiac organoids to model COVID-19 cytokine storm induced cardiac injuries

Acute cardiac injuries occur in 20%-25% of hospitalized COVID-19 patients. Herein, we demonstrate that human cardiac organoids (hCOs) are a viable platform to model the cardiac injuries caused by COVID-19 hyperinflammation. As IL-1β is an upstream cytokine and a core COVID-19 signature cytokine, it was used to stimulate hCOs to induce the release of a milieu of proinflammatory cytokines that mirror the profile of COVID-19 cytokine storm. The IL-1β treated hCOs recapitulated transcriptomic, structural, and functional signatures of COVID-19 hearts. The comparison of IL-1β treated hCOs with cardiac tissue from COVID-19 autopsies illustrated the critical roles of hyper-inflammation in COVID-19 cardiac insults and indicated the cardioprotective effects of endothelium. The IL-1β treated hCOs thus provide a defined and robust model to assess the efficacy and potential side effects of immunomodulatory drugs, as well as the reversibility of COVID-19 cardiac injuries at baseline and simulated exercise conditions.

Human intracardiac SSEA4+CD34 cells show features of cycling, immature cardiomyocytes and are distinct from Side Population and C-kit+CD45- cells

Cardiomyocyte proliferation has emerged as the main source of new cardiomyocytes in the adult. Progenitor cell populations may on the other hand contribute to the renewal of other cell types, including endothelial and smooth muscle cells. The phenotypes of immature cell populations in the adult human heart have not been extensively explored. We therefore investigated whether SSEA4+CD34- cells might constitute immature cycling cardiomyocytes in the adult failing and non-failing human heart. The phenotypes of Side Population (SP) and C-kit+CD45- progenitor cells were also analyzed. Biopsies from the four heart chambers were obtained from patients with end-stage heart failure as well as organ donors without chronic heart failure. Freshly dissociated cells underwent flow cytometric analysis and sorting. SSEA4+CD34- cells expressed high levels of cardiomyocyte, stem cell and proliferation markers. This pattern resembles that of cycling, immature, cardiomyocytes, which may be important in endogenous cardiac regeneration. SSEA4+CD34- cells isolated from failing hearts tended to express lower levels of cardiomyocyte markers as well as higher levels of stem cell markers. C-kit+CD45- and SP CD45- cells expressed high levels of endothelial and stem cell markers–corresponding to endothelial progenitor cells involved in endothelial renewal.

Human Cardiac Organoids to Model COVID-19 Cytokine Storm Induced Cardiac Injuries

Acute cardiac injuries occur in 20-25% of hospitalized COVID-19 patients. Despite urgent needs, there is a lack of 3D organotypic models of COVID-19 hearts for mechanistic studies and drug testing. Herein, we demonstrate that human cardiac organoids (hCOs) are a viable platform to model the cardiac injuries caused by COVID-19 hyperinflammation. As IL-1βis an upstream cytokine and a core COVID-19 signature cytokine, it was used to stimulate hCOs to induce the release of a milieu of proinflammatory cytokines that mirror the profile of COVID-19 cytokine storm. The IL-1 β treated hCOs recapitulated transcriptomic, structural, and functional signatures of COVID-19 hearts. The comparison of IL-1β treated hCOs with cardiac tissue from COVID-19 autopsies illustrated the critical roles of hyper-inflammation in COVID-19 cardiac insults and indicated the cardioprotective effects of endothelium. The IL-1β treated hCOs also provide a viable model to assess the efficacy and potential side effects of immunomodulatory drugs, as well as the reversibility of COVID-19 cardiac injuries at baseline and simulated exercise conditions.

Cytokine-Mediated Alterations of Human Cardiac Fibroblast's Secretome

Fibroblasts contribute to approximately 20% of the non-cardiomyocytic cells in the heart. They play important roles in the myocardial adaption to stretch, inflammation, and other pathophysiological conditions. Fibroblasts are a major source of extracellular matrix (ECM) proteins whose production is regulated by cytokines, such as TNF-α or TGF-β. The resulting myocardial fibrosis is a hallmark of pathological remodeling in dilated cardiomyopathy (DCM). Therefore, in the present study, the secretome and corresponding transcriptome of human cardiac fibroblasts from patients with DCM was investigated under normal conditions and after TNF-α or TGF-β stimulation. Secreted proteins were quantified via mass spectrometry and expression of genes coding for secreted proteins was analyzed via Affymetrix Transcriptome Profiling. Thus, we provide comprehensive proteome and transcriptome data on the human cardiac fibroblast’s secretome. In the secretome of quiescent fibroblasts, 58% of the protein amount belonged to the ECM fraction. Interestingly, cytokines were responsible for 5% of the total protein amount in the secretome and up to 10% in the corresponding transcriptome. Furthermore, cytokine gene expression and secretion were upregulated upon TNF-α stimulation, while collagen secretion levels were elevated after TGF-β treatment. These results suggest that myocardial fibroblasts contribute to pro-fibrotic and to inflammatory processes in response to extracellular stimuli.

Predominance of Heart Failure With Preserved Ejection Fraction in Postmenopausal Women: Intra- and Extra-Cardiomyocyte Maladaptive Alterations Scaffolded by Estrogen Deficiency

Heart failure (HF) remains a public health concern as it is associated with high morbidity and death rates. In particular, heart failure with preserved ejection fraction (HFpEF) represents the dominant (>50%) form of HF and mostly occurring among postmenopausal women. Hence, the initiation and progression of the left ventricular diastolic dysfunctions (LVDD) (a typically clinical manifestation of HFpEF) in postmenopausal women have been attributed to estrogen deficiency and the loss of its residue cardioprotective effects. In this review, from a pathophysiological and immunological standpoint, we discuss the probable multiple pathomechanisms resulting in HFpEF, which are facilitated by estrogen deficiency. The initial discussions recap estrogen and estrogen receptors (ERs) and β-adrenergic receptors (βARs) signaling under physiological/pathological states to facilitate cardiac function/dysfunction, respectively. By reconciling these prior discussions, attempts were made to explain how the loss of estrogen facilitates the disruptions both ERs and βARs-mediated signaling responsible for; the modulation of intra-cardiomyocyte calcium homeostasis, maintenance of cardiomyocyte cytoskeletal and extracellular matrix, the adaptive regulation of coronary microvascular endothelial functions and myocardial inflammatory responses. By scaffolding the disruption of these crucial intra- and extra-cardiomyocyte physiological functions, estrogen deficiency has been demonstrated to cause LVDD and increase the incidence of HFpEF in postmenopausal women. Finally, updates on the advancements in treatment interventions for the prevention of HFpEF were highlighted.

Amlexanox and Forskolin Prevents Isoproterenol-Induced Cardiomyopathy by Subduing Cardiomyocyte Hypertrophy and Maladaptive Inflammatory Responses

Chronic catecholamine stress (CCS) induces the occurrence of cardiomyopathy-pathological cardiac hypertrophy (PCH), which is characterized by left ventricular systolic dysfunction (LVSD). Recently, mounting evidence has implicated myocardial inflammation in the exacerbation of pathological cardiac remodeling. However, there are currently no well-defined treatment interventions or regimes targeted at both the attenuation of maladaptive myocardial hypertrophy and inflammation during CCS to prevent PCH. G protein-coupled receptor kinase 5 (GRK5) and adenylyl cyclases (ACs)-cAMP mediates both cardiac and inflammatory responses. Also, GRK5 and ACs are implicated in stress-induced LVSD. Herein, we aimed at preventing PCH during CCS via modulating adaptive cardiac and inflammatory responses by inhibiting GRK5 and/or stimulating ACs. Isoproterenol-induced cardiomyopathy (ICM) was modeled using 0.5 mg/100 g/day isoproterenol injections for 40 days. Alterations in cardiac and inflammatory responses were assessed from the myocardia. Similarities in the immunogenicity of cardiac troponin I (cTnI) and lipopolysaccharide under CCS were assessed, and Amlexanox (35 μM/ml) and/or Forskolin (10 μM/ml) were then employed in vitro to modulate adaptive inflammatory responses by inhibiting GRK5 or activating ACs-cAMP, respectively. Subsequently, Amlexanox (2.5 mg/100 g/day) and/or Forskolin (0.5 mg/100 g/day) were then translated into in vivo during CCS to modulate adaptive cardiac and inflammatory responses. The effects of Amlexanox and Forskolin on regulating myocardial systolic functions and inflammatory responses during CCS were ascertained afterward. PCH mice had excessive myocardial hypertrophy, fibrosis, and aggravated LVSD, which were accompanied by massive CD68⁺ inflammatory cell infiltrations. In vitro, Forskolin-AC/cAMP was effective than Amlexanox-GRK5 at downregulating proinflammatory responses during stress; nonetheless, Amlexanox and Forskolin combination demonstrated the most efficacy in modulating adaptive inflammatory responses. Individually, the translated Amlexanox and Forskolin treatment interventions were ineffective at subduing the pathological remodeling and sustaining cardiac function during CCS. However, their combination was potent at preventing LVSD during CCS by attenuating maladaptive myocardial hypertrophy, fibrosis, and inflammatory responses. The treatment intervention attained its potency mainly via Forskolin-ACs/cAMP-mediated modulation of cardiac and inflammatory responses, coupled with Amlexanox inhibition of GRK5 mediated maladaptive cascades. Taken together, our findings highlight the Amlexanox and Forskolin combination as a potential therapeutic intervention for preventing the occurrence of pathological cardiac hypertrophy during chronic stress.

Electrophysiological engineering of heart-derived cells with calcium-dependent potassium channels improves cell therapy efficacy for cardioprotection

We have shown that calcium-activated potassium (KCa)-channels regulate fundamental progenitor-cell functions, including proliferation, but their contribution to cell-therapy effectiveness is unknown. Here, we test the participation of KCa-channels in human heart explant-derived cell (EDC) physiology and therapeutic potential. TRAM34-sensitive KCa3.1-channels, encoded by the KCNN4 gene, are exclusively expressed in therapeutically bioactive EDC subfractions and maintain a strongly polarized resting potential; whereas therapeutically inert EDCs lack KCa3.1 channels and exhibit depolarized resting potentials. Somatic gene transfer of KCNN4 results in membrane hyperpolarization and increases intracellular [Ca²⁺], which boosts cell-proliferation and the production of pro-healing cytokines/nanoparticles. Intramyocardial injection of EDCs after KCNN4-gene overexpression markedly increases the salutary effects of EDCs on cardiac function, viable myocardium and peri-infarct neovascularization in a well-established murine model of ischemic cardiomyopathy. Thus, electrophysiological engineering provides a potentially valuable strategy to improve the therapeutic value of progenitor cells for cardioprotection and possibly other indications.

Strategies to improve the function of damaged hearts with progenitor cells have stalled. Here, the authors show that gene transfer of a calcium-dependent potassium channel enhances the functional properties and ability of explant-derived cells to improve heart function after a heart attack.

Histamine is involved in the regulation of collagen content in cultured heart myofibroblasts via H2, H3 and H4 histamine receptors

Histamine is involved in the regulation of collagen metabolism during healing following a myocardial infarction; however, its effects on the intact heart tissue is unknown. The aim of the present study was to determine whether histamine may influence collagen content in cells isolated from intact heart, and to identify the histamine receptor involved in the regulation of collagen deposition. Cells were isolated from intact rat hearts and subjected to identification by flow cytometry. The effects of histamine and its receptor agonists and antagonists were investigated. The heart cells were found to be actin, desmin and vimentin positive. Histamine (used at a concentrations of 1x10-10-1x10-5 M) increased collagen content within the culture and increased the expression of α1 chain of the procollagen type III gene. The H2, H3 and H4 receptor inhibitors ranitidine, ciproxifan and JNJ 7777120 blocked the effect of histamine on collagen content. All tested histamine receptor agonists, viz. 2-pyridylethylamine dihydrochloride (H1 receptor agonist), amthamine dihydrobromide (H2 receptor agonist), imetit (H3 receptor agonist) and 4-methylhistamine hydrochloride (H4 receptor agonist), elevated collagen content within the heart myofibroblast cultures. The cells isolated from the intact heart were identified as myofibroblasts. Thus, the results of the present study showed that histamine augmented collagen content in the heart myofibroblast culture by activation of three histamine receptors (H2, H3 and H4). The effect of the amine was also dependent on the activation of collagen type III gene expression.

Reversion inducing cysteine rich protein with Kazal motifs and cardiovascular diseases: The RECKlessness of adverse remodeling

The Reversion Inducing Cysteine Rich Protein With Kazal Motifs (RECK) is a glycosylphosphatidylinositol (GPI) anchored membrane-bound regulator of matrix metalloproteinases (MMPs). It is expressed throughout the body and plays a role in extracellular matrix (ECM) homeostasis and inflammation. In initial studies, RECK expression was found to be downregulated in various invasive cancers and associated with poor prognostic outcome. Restoring RECK, however, has been shown to reverse the metastatic phenotype. Downregulation of RECK expression is also reported in non-malignant diseases, such as periodontal disease, renal fibrosis, and myocardial fibrosis. As such, RECK induction has therapeutic potential in several chronic diseases. Mechanistically, RECK negatively regulates various matrixins involved in cell migration, proliferation, and adverse remodeling by targeting the expression and/or activation of multiple MMPs, A Disintegrin And Metalloproteinase Domain-Containing Proteins (ADAMs), and A Disintegrin And Metalloproteinase With Thrombospondin Motifs (ADAMTS). Outside of its role in remodeling, RECK has also been reported to exert anti-inflammatory effects. In cardiac diseases, for example, it has been shown to counteract several downstream effectors of Angiotensin II (Ang-II) that play a role in adverse cardiac and vascular remodeling, such as Interleukin-6 (IL-6)/IL-6 receptor (IL-6R)/glycoprotein 130 (IL-6 signal transducer) signaling and Epidermal Growth Factor Receptor (EGFR) transactivation. This review article focuses on the current understanding of the multifunctional effects of RECK and how its downregulation may contribute to adverse cardiovascular remodeling.

Dermal Drivers of Injury-Induced Inflammation: Contribution of Adipocytes and Fibroblasts

Irregular inflammatory responses are a major contributor to tissue dysfunction and inefficient repair. Skin has proven to be a powerful model to study mechanisms that regulate inflammation. In particular, skin wound healing is dependent on a rapid, robust immune response and subsequent dampening of inflammatory signaling. While injury-induced inflammation has historically been attributed to keratinocytes and immune cells, a vast body of evidence supports the ability of non-immune cells to coordinate inflammation in numerous tissues and diseases. In this review, we concentrate on the active participation of tissue-resident adipocytes and fibroblasts in pro-inflammatory signaling after injury, and how altered cellular communication from these cells can contribute to irregular inflammation associated with aberrant wound healing. Furthering our understanding of how tissue-resident mesenchymal cells contribute to inflammation will likely reveal new targets that can be manipulated to regulate inflammation and repair.

β2-Adrenergic Receptors Increase Cardiac Fibroblast Proliferation Through the Gαs/ERK1/2-Dependent Secretion of Interleukin-6

Fibroblasts are an important resident cell population in the heart involved in maintaining homeostasis and structure during normal conditions. They are also crucial in disease states for sensing signals and initiating the appropriate repair responses to maintain the structural integrity of the heart. This sentinel role of cardiac fibroblasts occurs, in part, through their ability to secrete cytokines. β-adrenergic receptors (βAR) are also critical regulators of cardiac function in the normal and diseased state and a major therapeutic target clinically. βAR are known to influence cytokine secretion in various cell types and they have been shown to be involved in cytokine production in the heart, but their role in regulating cytokine production in cardiac fibroblasts is not well understood. Thus, we hypothesized that βAR activation on cardiac fibroblasts modulates cytokine production to influence fibroblast function. Using primary fibroblast cultures from neonatal rats and adult mice, increased interleukin (IL)-6 expression and secretion occurred following β2AR activation. The use of pharmacological inhibitors and genetic manipulations showed that IL-6 elevations occurred through the Gαs-mediated activation of ERK1/2 and resulted in increased fibroblast proliferation. In vivo, a lack of β2AR resulted in increased infarct size following myocardial infarction and impaired wound closure in a murine dermal wound healing assay. These findings identify an important role for β2AR in regulating fibroblast proliferation through Gαs/ERK1/2-dependent alterations in IL-6 and may lead to the development of improved heart failure therapies through targeting fibrotic function of β2AR.

The Dynamic Interplay Between Cardiac Inflammation and Fibrosis

Heart failure is a leading cause of death worldwide. While there are multiple etiologies contributing to the development of heart failure, all cause result in impairments in cardiac function that is characterized by changes in cardiac remodeling and compliance. Fibrosis is associated with nearly all forms of heart failure and is an important contributor to disease pathogenesis. Inflammation also plays a critical role in the heart and there is a large degree of interconnectedness between the inflammatory and fibrotic response. This review discusses the cellular and molecular mechanisms contributing to inflammation and fibrosis and the interplay between the two.

Protective effects of rolipram on endotoxic cardiac dysfunction via inhibition of the inflammatory response in cardiac fibroblasts

BACKGROUND

Cardiac fibroblasts, regarded as the immunomodulatory hub of the heart, have been thought to play an important role during sepsis-induced cardiomyopathy (SIC). However, the detailed molecular mechanism and targeted therapies for SIC are still lacking. Therefore, we sought to investigate the likely protective effects of rolipram, an anti-inflammatory drug, on lipopolysaccharide (LPS)-stimulated inflammatory responses in cardiac fibroblasts and on cardiac dysfunction in endotoxic mice.

METHOD

Cardiac fibroblasts were isolated and stimulated with 1 μg/ml LPS for 6 h, and 10 μmol/l rolipram was administered for 1 h before LPS stimulation. mRNA levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in fibroblasts and their protein concentrations in supernatant were measured with real-time PCR (rt-PCR) and enzyme-linked immunosorbent assay, respectively. The expression of dual specificity phosphatase 1 (DUSP1), an endogenous negative regulator that inactivates MAPK-mediated inflammatory pathways, was also measured by rt-PCR and western blotting. DUSP1-targeted small interfering RNA (siRNA) was used to examine the specific role of DUSP1. To evaluate the role of rolipram in vivo, an endotoxic mouse model was established by intraperitoneal injection of 15 mg/kg LPS, and 10 mg/kg rolipram was intraperitoneally injected 1 h before LPS injection. mRNA and protein levels of inflammatory cytokines and DUSP1 in heart, inflammatory cell infiltration and cardiac function were all examined at 6 h after LPS injection.

RESULTS

The results showed that LPS could increase the expression and secretion of inflammatory cytokines and decrease the transcription and expression of DUSP1 in cardiac fibroblasts. However, rolipram pretreatment significantly reversed the LPS-induced downregulation of DUSP1 and inhibited LPS-induced upregulation and secretion of TNF-α and IL-6 but not IL-1β. Moreover, DUSP1-targeted siRNA experiments indicated that the protective effect of rolipram on inflammatory response was specific dependent on DUSP1 expression. Moreover, rolipram could further reduce inflammatory cell infiltration scores as shown by pathological analysis and increase the ejection fraction (EF) detected with echocardiography in the hearts of endotoxic mice.

CONCLUSIONS

Rolipram could improve endotoxin-induced cardiac dysfunction by upregulating DUSP1 expression to inhibit the inflammatory response in cardiac fibroblasts, which may be a potential treatment for SIC.

Immune-inflammatory concept of the pathogenesis of chronic heart failure in dogs with dilated cardiomyopathy

Background:

Dilated cardiomyopathy is common in dogs. This form of cardiomyopathy is the main cause of death due to heart disease in dogs. Death can occur suddenly in clinically normal animals as a result of the progression of congestive heart failure (CHF). The pathogenesis of heart failure syndrome in dogs with dilated cardiomyopathy involves activation of the neurohumoral system and immune-mediated inflammation, which leads to further progression of the condition. Heart failure syndrome in dogs with dilated cardiomyopathy is caused by the progressive loss of cardiomyocytes, apoptosis, remodeling of the left ventricle, systolic and diastolic dysfunction, arrhythmias, reduced cerebral blood flow, the involvement of other key internal organs, and intestinal dysbiosis.

Aim:

This study aimed to determine the immunological and inflammatory mechanisms surrounding the development of heart failure syndrome in dogs with dilated cardiomyopathy.

Materials and Methods:

The subjects of this study were dogs with a dilated form of cardiomyopathy (n=159), complicated by various functional classes of heart failure syndrome. Evaluation of myocardial remodeling, systolic function, and systemic hemodynamics was performed using EMP-860 Vet and PU-2200V ultrasound scanners according to the standard technique. Electrocardiography was performed with all dogs in right lateral recumbency using the EK1T-04 Midas electrocardiograph (50 mm/s speed and 1 mV gain = 1 cm).

Results:

In some affected animals, especially in cases of compensated dilated cardiomyopathy, leukocytosis was noted. In patients with dilated cardiomyopathy complicated by heart failure syndrome of various functional classes, the number of neutrophils was significantly increased, and the number of lymphocytes was decreased by 1.9-2.1 times when compared with those in clinically normal animals. In dogs with dilated cardiomyopathy, neutrophilic leukocytosis develops with a simple regenerative shift to the left. The results of immunological studies indicate that dogs with dilated cardiomyopathy develop T lymphocytopenia as compared with clinically normal animals.

Conclusion:

The central component of heart failure syndrome in dogs with dilated cardiomyopathy is the activation of the neurohumoral system and immune-mediated inflammation. The development of CHF in dogs with dilated cardiomyopathy is caused by the progressive loss of cardiomyocytes, apoptosis, remodeling of the left ventricle, systolic and diastolic dysfunction, arrhythmias, reduced cerebral blood flow, involvement of other key internal organs, and intestinal dysbiosis.