[T-TEER: description of a development process]. / T-TEER: Beschreibung eines Entwicklungsprozesses.

Tricuspid valve regurgitation (TR) is becoming increasingly more clinically important. While considered as an accompanying symptom of left heart pathologies in the past, TR is now seen as an independent and clinically significant condition. TR can lead to volume overload of the right ventricle, resulting in dilatation of the tricuspid valve annulus and worsening of the regurgitation. Undetected or untreated severe TR can lead to recurrent cardiac decompensation with hospitalization, reduced quality of life and death. Previous treatment options were limited to cardiac surgery and associated with high complication and mortality rates, especially in isolated TR. Therefore, many patients are considered inoperable so that the new interventional treatment measures nowadays often represent the only treatment option. Interventional treatment options such as the edge-to-edge procedure (T-TEER) with TriClip™ or the PASCAL™ system are very safe interventions that have already shown promising results, including reduction of TR, improvement in heart failure symptoms and the quality of life. The influence on the mortality and the necessity for hospitalization due to heart failure are currently being investigated in several randomized studies. Patient selection and timing of the intervention are crucial. Cardiovascular imaging plays a decisive role in selecting the appropriate method and timing of the intervention. The prognosis depends on factors, such as the severity of TR, right ventricular dysfunction, and pulmonary arterial hypertension. Overall, interventional TR treatment is a promising advancement in treatment from which many patients can benefit in the future.

Immune-mediated denervation of the pineal gland underlies sleep disturbance in cardiac disease.

Disruption of the physiologic sleep-wake cycle and low melatonin levels frequently accompany cardiac disease, yet the underlying mechanism has remained enigmatic. Immunostaining of sympathetic axons in optically cleared pineal glands from humans and mice with cardiac disease revealed their substantial denervation compared with controls. Spatial, single-cell, nuclear, and bulk RNA sequencing traced this defect back to the superior cervical ganglia (SCG), which responded to cardiac disease with accumulation of inflammatory macrophages, fibrosis, and the selective loss of pineal gland-innervating neurons. Depletion of macrophages in the SCG prevented disease-associated denervation of the pineal gland and restored physiological melatonin secretion. Our data identify the mechanism by which diurnal rhythmicity in cardiac disease is disturbed and suggest a target for therapeutic intervention.

Longitudinal In Vivo Monitoring of Atheroprogression in Hypercholesterolemic Mice Using Photoacoustic Imaging.

BACKGROUND AND AIM: The ability to recognize and monitor atherosclerotic lesion development using noninvasive imaging is crucial in preventive cardiology. The aim of the present study was to establish a protocol for longitudinal monitoring of plaque lipid, collagen, and macrophage burden as well as of endothelial permeability. METHODS AND RESULTS: Photoacoustic signals derived from endogenous or exogenous dyes assessed in vivo, in plaques of albino Apoe -/- mice, correlated with lesion characteristics obtained after histomorphometric and immunofluorescence analyses, thus supporting the validity of our protocol. Using models of atheroprogression and regression, we could apply our imaging protocol to the longitudinal observation of atherosclerotic lesion characteristics in mice. CONCLUSIONS: The present study shows an innovative approach to assess arterial inflammation in a non-invasive fashion, applicable to longitudinal analyses of changes of atherosclerotic lesion composition. Such approach could prove important in the preclinical testing of therapeutic interventions in mice carrying pre-established lesions.

Heterotopic Transcatheter Tricuspid Valve Replacement in a Patient With Carcinoid Heart Disease.

Neuroendocrine tumors can lead to carcinoid heart disease with subsequent development of severe tricuspid regurgitation due to thickening and restriction of the tricuspid leaflets. We present a patient who underwent successful heterotopic transcatheter tricuspid valve replacement for torrential tricuspid regurgitation due to carcinoid heart disease. (Level of Difficulty: Intermediate.).

Midkine-A novel player in cardiovascular diseases.

Midkine (MK) is a 13-kDa heparin-binding cytokine and growth factor with anti-apoptotic, pro-angiogenic, pro-inflammatory and anti-infective functions, that enable it to partake in a series of physiological and pathophysiological processes. In the past, research revolving around MK has concentrated on its roles in reproduction and development, tissue protection and repair as well as inflammatory and malignant processes. In the recent few years, MK's implication in a wide scope of cardiovascular diseases has been rigorously investigated. Nonetheless, there is still no broadly accepted consensus on whether MK exerts generally detrimental or favorable effects in cardiovascular diseases. The truth probably resides somewhere in-between and depends on the underlying physiological or pathophysiological condition. It is therefore crucial to thoroughly examine and appraise MK's participation in cardiovascular diseases. In this review, we introduce the MK gene and protein, its multiple receptors and signaling pathways along with its expression in the vascular system and its most substantial functions in cardiovascular biology. Further, we recapitulate the current evidence of MK's expression in cardiovascular diseases, addressing the various sources and modes of MK expression. Moreover, we summarize the most significant implications of MK in cardiovascular diseases with particular emphasis on MK's advantageous and injurious functions, highlighting its ample diagnostic and therapeutic potential. Also, we focus on conflicting roles of MK in a number of cardiovascular diseases and try to provide some clarity and guidance to MK's multifaceted roles. In summary, we aim to pave the way for MK-based diagnostics and therapies that could present promising tools in the diagnosis and treatment of cardiovascular diseases.

Association of Complement and MAPK Activation With SARS-CoV-2-Associated Myocardial Inflammation.

IMPORTANCE: Myocardial injury is a common feature of patients with SARS-CoV-2 infection. However, the cardiac inflammatory processes associated with SARS-CoV-2 infection are not completely understood. OBJECTIVE: To investigate the inflammatory cardiac phenotype associated with SARS-CoV-2 infection compared with viral myocarditis, immune-mediated myocarditis, and noninflammatory cardiomyopathy by integrating histologic, transcriptomic, and proteomic profiling. DESIGN, SETTING, AND PARTICIPANTS: This case series was a cooperative study between the Ludwig Maximilian University Hospital Munich and the Cardiopathology Referral Center at the University of Tübingen in Germany. A cohort of 19 patients with suspected myocarditis was examined; of those, 5 patients were hospitalized with SARS-CoV-2 infection between March and May 2020. Cardiac tissue specimens from those 5 patients were compared with specimens from 5 patients with immune-mediated myocarditis, 4 patients with non-SARS-CoV-2 viral myocarditis, and 5 patients with noninflammatory cardiomyopathy, collected from January to August 2019. EXPOSURES: Endomyocardial biopsy. MAIN OUTCOMES AND MEASURES: The inflammatory cardiac phenotypes were measured by immunohistologic analysis, RNA exome capture sequencing, and mass spectrometry-based proteomic analysis of endomyocardial biopsy specimens. RESULTS: Among 19 participants, the median age was 58 years (range, 37-76 years), and 15 individuals (79%) were male. Data on race and ethnicity were not collected. The abundance of CD163+ macrophages was generally higher in the cardiac tissue of patients with myocarditis, whereas lymphocyte counts were lower in the tissue of patients with SARS-CoV-2 infection vs patients with non-SARS-CoV-2 virus-associated and immune-mediated myocarditis. Among those with SARS-CoV-2 infection, components of the complement cascade, including C1q subunits (transcriptomic analysis: 2.5-fold to 3.6-fold increase; proteomic analysis: 2.0-fold to 3.4-fold increase) and serine/cysteine proteinase inhibitor clade G member 1 (transcriptomic analysis: 1.7-fold increase; proteomic analysis: 2.6-fold increase), belonged to the most commonly upregulated transcripts and differentially abundant proteins. In cardiac macrophages, the abundance of C1q was highest in SARS-CoV-2 infection. Assessment of important signaling cascades identified an upregulation of the serine/threonine mitogen-activated protein kinase pathways. CONCLUSIONS AND RELEVANCE: This case series found that the cardiac immune signature varied in inflammatory conditions with different etiologic characteristics. Future studies are needed to examine the role of these immune pathways in myocardial inflammation.

Proposal for a Standard Echocardiographic Tricuspid Valve Nomenclature.

OBJECTIVES: The purpose of this study was to introduce a novel clinically relevant nomenclature system for the TV and determine the relative incidence of each morphological type. BACKGROUND: With the rapid development of transcatheter tricuspid valve (TV) repair techniques, there is a growing recognition of the variability in leaflet morphology and a need for a unified nomenclature, which could aid in procedural planning and execution. METHODS: Patients from 4 medical centers (2 in Europe, 2 in the United States) referred for transesophageal echocardiography (TEE) to assess native TV function, were retrospectively analyzed for leaflet morphology with the use of a novel classification scheme. Four morphological types were identified: type I, 3 leaflets; type II, 2 leaflets; type IIIA, 4 leaflets with 2 anterior; type IIIB, 4 leaflets with 2 posterior; type IIIC, 4 leaflets with 2 septal; and type IV, >4 leaflets. RESULTS: A total of 579 patients were analyzed: mean age 78.1 ± 8.0 years, 50.4% female, 70.9% in atrial fibrillation, and 32.2% with previous left heart surgery or transcatheter intervention. Tricuspid regurgitation was moderate or less in 9.4%, severe in 40.5%, massive in 32.3%, and torrential in 17.7%. The etiology of tricuspid regurgitation was primary in 9.4%, mixed in 10.8%, and secondary in all of the other patients (18.6% atriogenic/isolated). The incidence of type I morphology was 312 of 579 (53.9%), type II was 26 of 579 (4.5%), type IIIA was 15 of 579 (2.6%), type IIIB was 186 of 579 (32.1%), type IIIC was 22 of 579 (3.8%), and type IV was 14 of 579 (2.4%). CONCLUSIONS: A novel TV leaflet nomenclature classification scheme can be used to identify 4 types of TV morphologies with the use of TEE imaging. From this multinational retrospective study, the TV has 3 well defined leaflets in only ∼54% of patients and 4 functional leaflets in ∼39% of patients, with type IIIB (2 posterior leaflets) being the most common of the latter. The utility of this classification scheme deserves further study.

Myocardial Inflammation and Dysfunction in COVID-19-Associated Myocardial Injury.

BACKGROUND: Myocardial injury, defined by elevated troponin levels, is associated with adverse outcome in patients with coronavirus disease 2019 (COVID-19). The frequency of cardiac injury remains highly uncertain and confounded in current publications; myocarditis is one of several mechanisms that have been proposed. METHODS: We prospectively assessed patients with myocardial injury hospitalized for COVID-19 using transthoracic echocardiography, cardiac magnetic resonance imaging, and endomyocardial biopsy. RESULTS: Eighteen patients with COVID-19 and myocardial injury were included in this study. Echocardiography revealed normal to mildly reduced left ventricular ejection fraction of 52.5% (46.5%-60.5%) but moderately to severely reduced left ventricular global longitudinal strain of -11.2% (-7.6% to -15.1%). Cardiac magnetic resonance showed any myocardial tissue injury defined by elevated T1, extracellular volume, or late gadolinium enhancement with a nonischemic pattern in 16 patients (83.3%). Seven patients (38.9%) demonstrated myocardial edema in addition to tissue injury fulfilling the Lake-Louise criteria for myocarditis. Combining cardiac magnetic resonance with speckle tracking echocardiography demonstrated functional or morphological cardiac changes in 100% of investigated patients. Endomyocardial biopsy was conducted in 5 patients and revealed enhanced macrophage numbers in all 5 patients in addition to lymphocytic myocarditis in 1 patient. SARS-CoV-2 RNA was not detected in any biopsy by quantitative real-time polymerase chain reaction. Finally, follow-up measurements of left ventricular global longitudinal strain revealed significant improvement after a median of 52.0 days (-11.2% [-9.2% to -14.7%] versus -15.6% [-12.5% to -19.6%] at follow-up; P=0.041). CONCLUSIONS: In this small cohort of COVID-19 patients with elevated troponin levels, myocardial injury was evidenced by reduced echocardiographic left ventricular strain, myocarditis patterns on cardiac magnetic resonance, and enhanced macrophage numbers but not predominantly lymphocytic myocarditis in endomyocardial biopsies.

[COVID-19: a cardiological point-of-view]. / COVID-19 aus Sicht der Kardiologie.

The SARS-CoV-2 pandemic has rapidly spread around the world and has led to a substantial morbidity and mortality in many countries. Although Corona Virus Disease 19 (COVID-19) is primarily a respiratory tract infection, there is growing evidence that other organs including the cardiovascular system are affected by COVID-19. In this review, we summarize the association of myocardial injury with in-hospital mortality of COVID-19 patients. Furthermore, we discuss potential mechanisms of myocardial injury including myocarditis and vascular thrombosis. Last, we review the current evidence on drugs which have been evaluated or are currently tested for the treatment of COVID-19 patients.

Endothelial CD40 Mediates Microvascular von Willebrand Factor-Dependent Platelet Adhesion Inducing Inflammatory Venothrombosis in ADAMTS13 Knockout Mice.

BACKGROUND: von Willebrand factor (vWF) plays an important role in platelet activation. CD40-CD40 ligand (CD40L) induced vWF release has been described in large vessels and cultured endothelium, but its role in the microcirculation is not known. Here, we studied whether CD40 is expressed in murine microvessels in vivo, whether CD40L induces platelet adhesion and leukocyte activation, and how deficiency of the vWF cleaving enzyme ADAMTS13 affects these processes. METHODS AND RESULTS: The role of CD40L in the formation of beaded platelet strings reflecting their adhesion to ultralarge vWF fibers (ULVWF) was analyzed in the murine cremaster microcirculation in vivo. Expression of CD40 and vWF was studied by immunohistochemistry in isolated and fixed cremasters. Microvascular CD40 was only expressed under inflammatory conditions and exclusively in venous endothelium. We demonstrate that CD40L treatment augmented the number of platelet strings, reflecting ULVWF multimer formation exclusively in venules and small veins. In ADAMTS13 knockout mice, the number of platelet strings further increased to a significant extent. As a consequence extensive thrombus formation was induced in venules of ADAMTS13 knockout mice. In addition, circulating leukocytes showed primary and rapid adherence to these platelet strings followed by preferential extravasation in these areas. CONCLUSION: CD40L is an important stimulus of microvascular endothelial ULVWF release, subsequent platelet string formation and leukocyte extravasation but only in venous vessels under inflammatory conditions. Here, the lack of ADAMTS13 leads to severe thrombus formation. The results identify CD40 expression and ADAMTS13 activity as important targets to prevent microvascular inflammatory thrombosis.

Blocking LFA-1 Aggravates Cardiac Inflammation in Experimental Autoimmune Myocarditis.

The lymphocyte function-associated antigen 1 (LFA-1) is a member of the beta2-integrin family and plays a pivotal role for T cell activation and leukocyte trafficking under inflammatory conditions. Blocking LFA-1 has reduced or aggravated inflammation depending on the inflammation model. To investigate the effect of LFA-1 in myocarditis, mice with experimental autoimmune myocarditis (EAM) were treated with a function blocking anti-LFA-1 antibody from day 1 of disease until day 21, the peak of inflammation. Cardiac inflammation was evaluated by measuring infiltration of leukocytes into the inflamed cardiac tissue using histology and flow cytometry and was assessed by analysis of the heart weight/body weight ratio. LFA-1 antibody treatment severely enhanced leukocyte infiltration, in particular infiltration of CD11b+ monocytes, F4/80+ macrophages, CD4+ T cells, Ly6G+ neutrophils, and CD133+ progenitor cells at peak of inflammation which was accompanied by an increased heart weight/body weight ratio. Thus, blocking LFA-1 starting at the time of immunization severely aggravated acute cardiac inflammation in the EAM model.

Midkine drives cardiac inflammation by promoting neutrophil trafficking and NETosis in myocarditis.

Heart failure due to dilated cardiomyopathy is frequently caused by myocarditis. However, the pathogenesis of myocarditis remains incompletely understood. Here, we report the presence of neutrophil extracellular traps (NETs) in cardiac tissue of patients and mice with myocarditis. Inhibition of NET formation in experimental autoimmune myocarditis (EAM) of mice substantially reduces inflammation in the acute phase of the disease. Targeting the cytokine midkine (MK), which mediates NET formation in vitro, not only attenuates NET formation in vivo and the infiltration of polymorphonuclear neutrophils (PMNs) but also reduces fibrosis and preserves systolic function during EAM. Low-density lipoprotein receptor-related protein 1 (LRP1) acts as the functionally relevant receptor for MK-induced PMN recruitment as well as NET formation. In summary, NETosis substantially contributes to the pathogenesis of myocarditis and drives cardiac inflammation, probably via MK, which promotes PMN trafficking and NETosis. Thus, MK as well as NETs may represent novel therapeutic targets for the treatment of cardiac inflammation.

A Fundamental Role of Myh9 for Neutrophil Migration in Innate Immunity.

Neutrophils are the first leukocytes to arrive at sites of injury during the acute inflammatory response. To maintain the polarized morphology during migration, nonmuscle myosins class II are essential, but studies using genetic models to investigate the role of Myh9 for neutrophil migration were missing. In this study, we analyzed the functional role of Myh9 on neutrophil trafficking using genetic downregulation of Myh9 in Vav-iCre+/Myh9wt/fl mice because the complete knockout of Myh9 in the hematopoietic system was lethal. Migration velocity and Euclidean distance were significantly diminished during mechanotactic migration of Vav-iCre+/Myh9wt/fl neutrophils compared with Vav-iCre-/Myh9wt/fl control neutrophils. Similar results were obtained for transmigration and migration in confined three-dimensional environments. Stimulated emission depletion nanoscopy revealed that a certain threshold of Myh9 was required to maintain proper F-actin dynamics in the front of the migrating cell. In laser-induced skin injury and in acute peritonitis, reduced Myh9 expression in the hematopoietic system resulted in significantly diminished neutrophil extravasation. Investigation of bone marrow chimeric mice in the peritonitis model revealed that the migration defect was cell intrinsic. Expression of Myh9-EGFP rescued the Myh9-related defects in two-dimensional and three-dimensional migration of Hoxb8-SCF cell-derived neutrophils generated from fetal liver cells with a Myh9 knockdown. Live cell imaging provided evidence that Myh9 was localized in branching lamellipodia and in the uropod where it may enable fast neutrophil migration. In summary, the severe migration defects indicate an essential and fundamental role of Myh9 for neutrophil trafficking in innate immunity.

The Role of Midkine in Arteriogenesis, Involving Mechanosensing, Endothelial Cell Proliferation, and Vasodilation.

Mechanical forces in blood circulation such as shear stress play a predominant role in many physiological and pathophysiological processes related to vascular responses or vessel remodeling. Arteriogenesis, defined as the growth of pre-existing arterioles into functional collateral arteries compensating for stenosed or occluded arteries, is such a process. Midkine, a pleiotropic protein and growth factor, has originally been identified to orchestrate embryonic development. In the adult organism its expression is restricted to distinct tissues (including tumors), whereby midkine is strongly expressed in inflamed tissue and has been shown to promote inflammation. Recent investigations conferred midkine an important function in vascular remodeling and growth. In this review, we introduce the midkine gene and protein along with its cognate receptors, and highlight its role in inflammation and the vascular system with special emphasis on arteriogenesis, particularly focusing on shear stress-mediated vascular cell proliferation and vasodilatation.

Cathelicidins prime platelets to mediate arterial thrombosis and tissue inflammation.

Leukocyte-released antimicrobial peptides contribute to pathogen elimination and activation of the immune system. Their role in thrombosis is incompletely understood. Here we show that the cathelicidin LL-37 is abundant in thrombi from patients with acute myocardial infarction. Its mouse homologue, CRAMP, is present in mouse arterial thrombi following vascular injury, and derives mainly from circulating neutrophils. Absence of hematopoietic CRAMP in bone marrow chimeric mice reduces platelet recruitment and thrombus formation. Both LL-37 and CRAMP induce platelet activation in vitro by involving glycoprotein VI receptor with downstream signaling through protein tyrosine kinases Src/Syk and phospholipase C. In addition to acute thrombosis, LL-37/CRAMP-dependent platelet activation fosters platelet-neutrophil interactions in other inflammatory conditions by modulating the recruitment and extravasation of neutrophils into tissues. Absence of CRAMP abrogates acid-induced lung injury, a mouse pneumonia model that is dependent on platelet-neutrophil interactions. We suggest that LL-37/CRAMP represents an important mediator of platelet activation and thrombo-inflammation.

Lower frequency routine surveillance endomyocardial biopsies after heart transplantation.

In heart transplantation (HTx) patients, routine surveillance endomyocardial biopsies (rsEMB) are recommended for the detection of early cardiac allograft rejection. However, there is no consensus on the optimal frequency of rsEMB. Frequent rsEMB have shown a low diagnostic yield in the new era of potent immunosuppressive regimen. Efficacy and safety of lower frequency rsEMB have not been investigated so far. In this retrospective, single centre, observational study we evaluated 282 patients transplanted between 2004 and 2014. 218 of these patients were investigated by rsEMB and symptom-triggered EMB (stEMB). We evaluated EMB results, complications, risk factors for rejection, survival 1 and 5 years as well as incidence of cardiac allograft vasculopathy (CAV) 3 years after HTx. A mean of 7.1 ± 2.5 rsEMB were conducted per patient within the first year after HTx identifying 7 patients with asymptomatic and 9 patients with symptomatic acute rejection requiring glucocorticoide pulse therapy. Despite this relatively low frequency of rsEMB, only 6 unscheduled stEMB were required in the first year after HTx leading to 2 additional treatments. In 6 deaths among all 282 patients (2.1%), acute rejection could not be ruled out as a potential underlying cause. Overall survival at 1 year was 78.7% and 5-year survival was 74%. Incidence of CAV was 17% at 3-year follow-up. Morbidity and mortality of lower frequency rsEMB are comparable with data from the International Society for Heart and Lung Transplantation (ISHLT) registry. Consensus is needed on the optimal frequency of EMB.

The cytokine midkine supports neutrophil trafficking during acute inflammation by promoting adhesion via ß2 integrins (CD11/CD18).

Emerging evidence suggests a role of the cytokine midkine (MK) in inflammation. In this study, its functional relevance for recruitment of polymorphonuclear neutrophils (PMNs) during acute inflammation was investigated. Intravital microscopy and histologic analysis of tumor necrosis factor-α-stimulated cremaster muscle venules revealed severely compromised leukocyte adhesion and extravasation in MK(-/-) mice compared with MK(+/+) animals. Systemic administration of recombinant MK completely rescued the adhesion defect in MK(-/-) mice. In a hind limb ischemia model, leukocyte accumulation in MK(-/-) mice was significantly diminished compared with MK(+/+) animals. However, MK did not lead to an inflammatory activation of PMNs or endothelial cells suggesting that it does not serve as classical proinflammatory cytokine. Unexpectedly, immobilized MK mediated PMN adhesion under static and flow conditions, whereas PMN-derived MK was dispensable for the induction of adhesion. Furthermore, adhesion strengthening remained unaffected by MK. Flow cytometry revealed that immobilized, but not soluble MK, significantly promoted the high affinity conformation of ß2 integrins of PMNs. Blocking studies of low-density lipoprotein receptor-related protein 1 (LRP1) suggested that LRP1 may act as a receptor for MK on PMNs. Thus, MK seems to support PMN adhesion by promoting the high affinity conformation of ß2 integrins, thereby facilitating PMN trafficking during acute inflammation.

Midkine acts as proangiogenic cytokine in hypoxia-induced angiogenesis.

The cytokine midkine (MK) promotes tumor growth mainly by inducing angiogenesis. Here, we identified the source of MK in the vascular system under hypoxic conditions and demonstrated the relevance of MK during ischemia of normal tissue. Hypoxia increased MK protein expression in human polymorphonuclear neutrophils (PMN), monocytes, and human umbilical vein endothelial cells (HUVEC) compared with normoxia. Immunoelectron microscopy showed elevated cell surface expression of MK in PMN and monocytes during hypoxia. However, only HUVEC released significant amounts of soluble MK during hypoxia compared with normoxia (301 ± 81 pg/ml vs. 158 ± 45 pg/ml; P < 0.05). Exogenous MK induced neovascularization in a chorioallantoic membrane (CAM) assay compared with negative control as measured by counting the number of branching points per visual field (1,074 ± 54 vs. 211 ± 70; P < 0.05). In a hind limb ischemia model, the angiogenic response was almost completely absent in MK-deficient mice, whereas control animals showed a profound angiogenic response measured as proliferating endothelial cells per visual field (45 ± 30 vs. 169 ± 34; P < 0.01). These unanticipated results identified endothelial cells as the source of soluble MK in the vascular system during hypoxia and defined MK as a pivotal player of angiogenesis during ischemia in nonmalignant tissue.