Post-cardiac injury syndrome and an increased humoral immune response against the major contractile proteins (actin and myosin)

Diagnostic and prognostic role of cardiac pathology multicomplex autoimmune biological markers

Relevance . Despite the large list of biological markers of cardiovascular diseases, not all have evidence-b ased effectiveness and independent prognostic value. Laboratory diagnostics of serum cardiospecific auto-antibodies for the diagnosis of myocyte cell damage has several potential advantages compared to the evaluation of traditional methods. These include the analysis of natural globulins to troponin I (cTnI), to alpha-a ctin 1 (ACTC1), to the heavy chain of beta-myosin 7B (MUN7B), which are based on a self-sustaining immune response to the myocardium’s own auto-antigens, which leads to damage to the cells expressing them. Purpose: To determine the diagnostic and practical value of quantitative indicators for the autoantibody complex to cardiomyocyte proteins to troponin I, to alpha-a ctin 1 and to the heavy chain of beta-myosin 7B in patients with cardiac pathology. Materials and Methods. The study of auto-antibodies to cTnI, ACTC1 and MUN7B in blood serum using laboratory enzyme immunoassay was carried out in patients with cardiac pathology undergoing inpatient treatment at the Regional Clinical Cardiology Dispensary in Stavropol. Additionally, an instrumental and laboratory examination was carried out in accordance with the clinical recommendations developed by the Association of Cardiovascular Surgeons, the Cardiological Society of Russia and approved by the Scientific and Practical Council of the Ministry of Health of the Russian Federation. The work was examined and approved by the Ethics Committee of the North Caucasus Federal University. Results and Discussion . Changes in the level of autoantibodies to cTnI, ACTC1 and MUN7B proteins in blood serum were statistically significant (p 0.01 v. s. p 0.01). A persistent increase in the level of auto-antibodies to cTnI by 2.36 ng/ml (694.11 %), to ACTC1 by 3.6 ng/ml (141.73 %) and to MUN7B by 1.74 ng/ml (119.17 %) was found in individuals with confirmed cardiac pathology, when other criteria for laboratory analysis were within acceptable values, which determine their diagnostic and evidentiary effectiveness. Conclusion . The results of the study showed the relationship of changes in the activity of cardiospecific auto-A T to cardiomyocyte proteins (Anti-cTnI, Anti ACTC1, Anti-M YH7B) in patients with cardiac pathologies, indicating not only systemic membrane disorders (membranopathies), but also serve as convincing evidence of direct chemical changes in cardiomyocytes. A correlation has also been established between cardiomarkers of necrosis and ischemia and autoimmune globulins Anti-cTnI, Anti ACTC1, Anti-MYH7B, that confirms diagnostic and practical value of this laboratory analysis.

Combined therapy with dapagliflozin and entresto offers an additional benefit on improving the heart function in rat after ischemia-reperfusion injury

BACKGROUND

This study tested whether combined dapagliflozin and entresto treatment would be superior to either one alone for preserving the left-ventricular ejection-fraction (LVEF) in rat after ischemia-reperfusion (IR) injury.

METHODS AND RESULTS

In vitro flow-cytometric result showed that the intracellular and mitochondrial reactive oxygen species and mitochondrial permeability transition pore, and protein levels of oxidative-stress/DNA-damaged markers [NADPH-oxidase-1 (NOX-1)/NOX-2/oxidized-protein/γ-H2A-histone-family member X (γ-H2AX)] were significantly higher in hydrogen peroxide (H₂O₂) (300μM)-treated H9C2 cells as compared with the controls that were significantly reversed in sacubitril/valsartan and dapagliflozin therapy in the same H₂O₂-treated condition, whereas the protein expressions of antioxidants [Sirtuin-1 (SIRT1)/SIRT3/superoxide dismutase/catalase/glutathione peroxidase) exhibited an opposite pattern among the groups (all p<0.001). Adult-male-Sprague-Dawley rat (n=40) were equally categorized into group 1 (sham-operated control), group 2 (IR), group 3 (IR+dapagliflozin/20mg/kg/orally at 3h and post-days 1/2/3 after IR), group 4 (IR+entresto/100mg/kg/orally at 3h and post-days 1/2/3 after IR) and group 5 (IR+dapagliflozin+entresto) and the hearts were harvested by day 3 after IR. The 3^rd day's LVEF was highest in group 1, lowest in group 2 and significantly higher in group 5 than in groups 3/4, but it was similar between the latter two groups (p<0.001). The protein expressions of oxidative-stress (NOX-1/NOX-2/oxidized protein), fibrotic (transforming-growth factor-ß/phosphorylated-Smad3), apoptotic [mitochondrial-Bax/cleaved-caspase-3/cleaved-poly (ADP-ribose) polymerase], mitochondria/DNA damaged (cytosolic-cytochrome-C/γ-H2AX), pressure-overload/heart-failure [brain natriuretic peptide (BNP)/ß-myosin heavy chain] and autophagic (ratio of meiotic cyclins CLB3-II/CLB3-I) biomarkers, and the upstream (high-mobility group box 1/Toll-like receptor-4/MyD88/phosphorylated-nuclear factor-κB and downstream [interleukin (IL)-1ß/IL-6/tumor necrosis factor-α] inflammatory signalings revealed an antithetical features of LVEF among the groups (all p<0.0001). The cellular levels of inflammatory (myeloperoxidase+/CD68+), pressure-overload/heart-failure (BNP+) and DNA-damage (γ-H2AX+) biomarkers as well as infarct area demonstrated an opposite pattern of LVEF among the groups (all p<0.0001).

CONCLUSION

Incorporated entresto-dapagliflozin treatment was superior to either one alone on protecting the heart against IR injury.

Immunosuppressive effects of dimethyl fumarate on dendritic cell maturation and migration: a potent protector for coronary heart disease

Dendritic cells (DCs), as a bridge between innate and adaptive immunity, play key roles in atherogenesis, particularly in plaque rupture, the underlying pathophysiologic cause of myocardial infarction. Targeting DC functions, including maturation and migration to atherosclerotic plaques, may be a novel therapeutic approach to atherosclerotic disease. Dimethyl fumarate (DMF), an agent consisting of a combination of fumaric acid esters, in current study were found to be able to suppress DC maturation by reducing the expression of costimulatory molecules and MHC class II and by blocking cytokine secretion. In addition, DMF efficiently inhibited the migration of activated DCs in vitro and in vivo by reducing the expression of chemokine receptor 7 (CCR7). Additionally, DMF efficiently inhibited the expression of the costimulatory molecule CD86, as well as the chemokine receptor CCR7 and the C-X-C motif chemokine receptor 4 (CXCR4), in healthy donor-derived purified DCs that had been stimulated by ST-segment elevation myocardial infarction (STEMI) patient serum. This study points to the potent therapeutic value of DMF for protecting against cardiovascular disease by suppressing DC functions.

Systematic Understanding of Pathophysiological Mechanisms of Oxidative Stress-Related Conditions-Diabetes Mellitus, Cardiovascular Diseases, and Ischemia-Reperfusion Injury

Reactive oxygen species (ROS) plays a role in intracellular signal transduction under physiological conditions while also playing an essential role in diseases such as hypertension, ischemic heart disease, and diabetes, as well as in the process of aging. The influence of ROS has some influence on the frequent occurrence of cardiovascular diseases (CVD) in diabetic patients. In this review, we considered the pathophysiological relationship between diabetes and CVD from the perspective of ROS. In addition, considering organ damage due to ROS elevation during ischemia-reperfusion, we discussed heart and lung injuries. Furthermore, we have focused on the transient receptor potential (TRP) channels and L-type calcium channels as molecular targets for ROS in ROS-induced tissue damages and have discussed about the pathophysiological mechanism of the injury.

Immune cell Dilemma in Ischemic Cardiomyopathy: To Heal or Not to Heal

Inflammation is a double-edged sword for sterile tissue injury such as in myocardial infarction (MI). After ischemic injury, inflammatory immune responses activate repair processes, clear tissue-debris, form a stable scar and initiate angiogenesis in the myocardium for efficient wound-healing. However, incomplete immune resolution or sustained low-grade inflammation lead to ischemic cardiomyopathy (IC) characterized by maladaptive tissue remodeling and left-ventricular dilatation. It is clear that a delicate balance of cytokines, chemokines, prostaglandins, resolvins, and the innate and adaptive immune systems is critical for adequate healing as both insufficient- or overt-activation of inflammatory responses can either enhance rupture incidence or exacerbate cardiac dysfunction in the long-term. Among all the players, immune cells are the most critical as they are not only a source for all of the inflammatory protein mediators, but are also a target. However, phenotypic complexities associated with different immune subtypes, their interdependence, phasic-activations and varied functionalities often make it difficult to segregate the effects of one immune cell from another. In this review, we briefly summarize the role of several innate and adaptive immune cells to acquaint readers with complex immune-networks that dictate the extent of wound-healing post-MI and maladaptive remodeling during IC.

Postpericardiotomy syndrome after cardiac surgery

Postpericardiotomy syndrome (PPS) is a well-known complication after cardiac surgery. The syndrome results in prolonged hospital stay, readmissions, and invasive interventions. Previous studies have reported inconsistent results concerning the incidence and risk factors for PPS due to the differences in the applied diagnostic criteria, study designs, patient populations, and procedure types. In recent prospective studies the reported incidences have been between 21 and 29% in adult cardiac surgery patients. However, it has been stated that most of the included diagnoses in the aforementioned studies would be clinically irrelevant. This challenges the specificity and usability of the currently recommended diagnostic criteria for PPS. Moreover, recent evidence suggests that PPS requiring invasive intervention such as the evacuation of pleural and/or pericardial effusion is associated with increased mortality. In the present review, we summarise the existing literature concerning the incidence, clinical features, diagnostic criteria, risk factors, management, and prognosis of PPS. We also propose novel approaches regarding to the definition and diagnosis of PPS. Key messages: Current diagnostic criteria of PPS should be reconsidered, and the analyses should be divided into subgroups according to the severity of the syndrome to achieve more clinically applicable and meaningful results in the future studies. In contrast with the previous presumption, severe PPS - defined as PPS requiring invasive interventions - was recently found to be associated with higher all-cause mortality during the first two years after cardiac surgery. The association with an increased mortality supports the use of relatively aggressive prophylactic methods to prevent PPS. The risk factors clearly increasing the occurrence of PPS are younger age, pleural incision, and valve and ascending aortic procedures when compared to CABG.

Synergistic Activation of Toll-Like and NOD Receptors by Complementary Antigens as Facilitators of Autoimmune Disease: Review, Model and Novel Predictions

Persistent activation of toll-like receptors (TLR) and nucleotide-binding oligomerization domain-containing proteins (NOD) in the innate immune system is one necessary driver of autoimmune disease (AD), but its mechanism remains obscure. This study compares and contrasts TLR and NOD activation profiles for four AD (autoimmune myocarditis, myasthenia gravis, multiple sclerosis and rheumatoid arthritis) and their animal models. The failure of current AD theories to explain the disparate TLR/NOD profiles in AD is reviewed and a novel model is presented that explains innate immune support of persistent chronic inflammation in terms of unique combinations of complementary AD-specific antigens stimulating synergistic TLRs and/or NODs. The potential explanatory power of the model is explored through testable, novel predictions concerning TLR- and NOD-related AD animal models and therapies.

Healing the Broken Heart; The Immunomodulatory Effects of Stem Cell Therapy

Cardiovascular Disease (CVD) is a leading cause of mortality within the United States. Current treatments being administered to patients who suffered a myocardial infarction (MI) have increased patient survival, but do not facilitate the replacement of damaged myocardium. Recent studies demonstrate that stem cell-based therapies promote myocardial repair; however, the poor engraftment of the transferred stem cell populations within the infarcted myocardium is a major limitation, regardless of the cell type. One explanation for poor cell retention is attributed to the harsh inflammatory response mounted following MI. The inflammatory response coupled to cardiac repair processes is divided into two distinct phases. The first phase is initiated during ischemic injury when necrosed myocardium releases Danger Associated Molecular Patterns (DAMPs) and chemokines/cytokines to induce the activation and recruitment of neutrophils and pro-inflammatory M1 macrophages (MΦs); in turn, facilitating necrotic tissue clearance. During the second phase, a shift from the M1 inflammatory functional phenotype to the M2 anti-inflammatory and pro-reparative functional phenotype, permits the resolution of inflammation and the establishment of tissue repair. T-regulatory cells (Tregs) are also influential in mediating the establishment of the pro-reparative phase by directly regulating M1 to M2 MΦ differentiation. Current studies suggest CD4+ T-lymphocyte populations become activated when presented with autoantigens released from the injured myocardium. The identity of the cardiac autoantigens or paracrine signaling molecules released from the ischemic tissue that directly mediate the phenotypic plasticity of T-lymphocyte populations in the post-MI heart are just beginning to be elucidated. Stem cells are enriched centers that contain a diverse paracrine secretome that can directly regulate responses within neighboring cell populations. Previous studies identify that stem cell mediated paracrine signaling can influence the phenotype and function of immune cell populations in vitro, but how stem cells directly mediate the inflammatory microenvironment of the ischemic heart is poorly characterized and is a topic of extensive investigation. In this review, we summarize the complex literature that details the inflammatory microenvironment of the ischemic heart and provide novel insights regarding how paracrine mediated signaling produced by stem cell-based therapies can regulate immune cell subsets to facilitate pro-reparative myocardial wound healing.

Postcardiac injury syndrome after cardiac implantable electronic device implantation

Background

Postcardiac injury syndrome (PCIS) is an inflammatory complication that derives from injury to the epicardium, myocardium, or endocardium. It occurs after trauma, myocardial infarction, percutaneous coronary intervention, cardiac surgery, intracardiac ablation, and implantation of cardiac implantable electronic device (CIED). In this study we assessed the incidence of PCIS after CIED implantation and its possible risk factors.

Material and methods

All patients who received CIED implantation at Heidelberg University Hospital between 2000 and 2014 were evaluated (n = 4989 patients). Clinical data including age, sex, underlying cardiac disease, type of implanted CIED, location of electrode implantation, clinical symptoms, time of symptom onset of PCIS, therapy, and outcome were extracted and analyzed.

Results

We identified 19 cases of PCIS in 4989 patients, yielding an incidence of 0.38%. The age of patients with PCIS ranged from 39 to 86 years. Dilated cardiomyopathy (DCM) as underlying cardiac disease and right atrial (RA) lead implantation had a significant association with occurrence of PCIS (p = 0.045 in DCM and p < 0.001 in RA lead implantation). Dyspnea, chest pain, dry cough, and fever were the most frequently reported symptoms in patients with PCIS. Pericardial and pleura effusion as well as elevated C‑reactive protein (CRP), increased erythrocyte sedimentation rate (ESR), and leukocytosis were the most common findings.

Conclusion

To the best of our knowledge, this is the largest cohort evaluating the incidence of PCIS after CIED implantation. The data show that PCIS is a rare complication after CIED implantation and occurs more frequently in patients with DCM and those with RA lead implantation. Although rare and mostly benign, PCIS can lead to potentially lethal complications and physicians must be aware of its symptoms.

Electronic supplementary material

The online version of this article (10.1007/s00059-020-04910-6) contains supplementary material, which is available to authorized users.

Combined Therapy with SS31 and Mitochondria Mitigates Myocardial Ischemia-Reperfusion Injury in Rats

Myocardial ischemia-reperfusion (IR) injury contributes to adverse cardiac outcomes after myocardial ischemia, cardiac surgery, or circulatory arrest. In this study, we evaluated the ability of combined SS31-mitochondria (Mito) therapy to protect heart cells from myocardial IR injury. Adult male SD rats (n = 8/each group) were randomized: group 1 (sham-operated control), group 2 (IR, 30-min ischemia/72 h reperfusion), group 3 (IR-SS31 (2 mg intra-peritoneal injection at 30 min/24 h/48 h after IR)), group 4 (IR-mitochondria (2 mg/derived from donor liver/intra-venous administration/30 min after IR procedure)), and group 5 (IR-SS31-mitochondria). In H9C2 cells, SS31 suppressed menadione-induced oxidative-stress markers (NOX-1, NOX-2, oxidized protein) while it increased SIRT1/SIRT3 expression and ATP levels. In adult male rats 72 h after IR, left ventricular ejection fraction (LVEF) was highest in sham-operated control animals and lowest in the IR group. LVEF was also higher in IR rats treated with SS31-Mito than untreated IR rats or those treated with Mito or SS31 alone. Areas of fibrosis/collagen-deposition showed the opposite pattern. Likewise, levels of oxidative-stress markers (NOX-1, NOX-2, oxidized protein), inflammatory markers (MMP-9, CD11, IL-1β, TNF-α), apoptotic markers (mitochondrial-Bax, cleaved-caspase-3, PARP), fibrosis markers (p-Smad3, TGF-β), DNA-damage (γ-H2AX), sarcomere-length, and pressure/volume overload markers (BNP, β-MHC) all showed a pattern opposite that of LVEF. Conversely, anti-apoptotic (BMP-2, Smad1/5) and energy integrity (PGC-1α/mitochondrial cytochrome-C) markers exhibited a pattern identical to that of LVEF. This study demonstrates that the combined SS31-Mito therapy is superior to either therapy alone for protecting myocardium from IR injury and indicates that the responsible mechanisms involved increased SIRT1/SIRT3 expression, which suppresses inflammation and oxidative stress and protects mitochondrial integrity.

Antibodies aggravate the development of ischemic heart failure

Heart-specific antibodies have been widely associated with myocardial infarction (MI). However, it remains unclear whether autoantibodies mediate disease progression or are a byproduct of cardiac injury. To disambiguate the role of immunoglobulins in MI, we characterized the development of ischemic heart failure in agammaglobulinemic mice (AID^-/-μS^-/-). Although these animals can produce functional B cells, they cannot synthesize secretory IgM (μS^-/-) or perform Ig class switching (AID^-/-), leading to complete antibody deficiency. Agammaglobulinemia did not affect overall post-MI survival but resulted in a significant reduction in infarct size. Echocardiographic analyses showed that, compared with wild-type infarcted control mice, AID^-/-μS^-/- mice exhibited improved cardiac function and reduced remodeling on day 56 post-MI. These differences remained significant even after animals with matched infarct sizes were compared. Infarcted AID^-/-μS^-/- mice also showed reduced myocardial expression levels of transcripts known to promote adverse remodeling, such as matrix metalloproteinase-9, collagen type I a1, collagen type III a1, and IL-6. An unbiased screening of the heart reactivity potential in the plasma of wild-type MI animals revealed the presence of antibodies that target the myocardial scar and collagenase-sensitive epitopes. Moreover, we found that IgG accumulated within the scar tissues of infarcted mice and remained in close proximity with cells expressing Fcγ receptors (CD16/32), suggesting the existence of an in situ IgG-Fcγ receptor axis. Collectively, our study results confirm that antibodies contribute to ischemic heart failure progression and provide novel insights into the mechanisms underlying this phenomenon. NEW & NOTEWORTHY Our study sheds some light on the long-standing debate over the relevance of autoantibodies in heart failure and might stimulate future research in the field. The observation of extracellular matrix-specific antibodies and the detection of Fcγ receptor-expressing cells within the scar provide novel insights into the mechanisms by which antibodies may contribute to adverse remodeling.

Suppression of T cells by mesenchymal and cardiac progenitor cells is partly mediated via extracellular vesicles

Adverse remodeling after myocardial infarction (MI) is strongly influenced by T cells. Stem cell therapy after MI, using mesenchymal stem cells (MSC) or cardiomyocyte progenitor cells (CMPC), improved cardiac function, despite low cell retention and limited differentiation. As MSC secrete many factors affecting T cell proliferation and function, we hypothesized the immune response could be affected as one of the targets of stem cell therapy. Therefore, we studied the immunosuppressive properties of human BM-MSC and CMPC and their extracellular vesicles (EVs) in co-culture with activated T cells. Proliferation of T cells, measured by carboxyfluorescein succinimidyl ester dilution, was significantly reduced in the presence of BM-MSC and CMPC. The inflammatory cytokine panel of the T cells in co-culture, measured by Luminex assay, changed, with strong downregulation of IFN-gamma and TNF-alpha. The effect on proliferation was observed in both direct cell contact and transwell co-culture systems. Transfer of conditioned medium to unrelated T cells abrogated proliferation in these cells. EVs isolated from the conditioned medium of BM-MSC and CMPC prevented T cell proliferation in a dose-dependent fashion. Progenitor cells presence induces up- and downregulation of multiple previously unreported pathways in T cells. In conclusion, both BM-MSC and CMPC have a strong capacity for in vitro immunosuppression. This effect is mediated by paracrine factors, such as extracellular vesicles. Besides proliferation, many additional pathways are influenced by both BM-MSC and CMPC.

Systemic inflammatory response syndromes in the era of interventional cardiology

Systemic inflammatory response syndrome (SIRS), initially reported after cardiovascular surgery, has been described after various interventional cardiology procedures, including endovascular/thoracic aortic repair (EVAR/TEVAR), implantation of heart rhythm devices, percutaneous coronary intervention (PCI), electrophysiology procedures (EP), and transcatheter aortic valve implantation (TAVI). In these settings, a comprehensive understanding of the triggers, pathogenesis as well as a common diagnostic/therapeutic algorithm is lacking and will be discussed in this review. SIRS occurs in about 40% and 50% of patients undergoing TEVAR/EVAR and TAVI respectively; it affects 0.1% of patients undergoing implantation of heart rhythm devices. Prevalence is unknown after PCI or EP. Clinical presentation includes fever, dyspnoea/tachypnoea, tachycardia, weakness, chest pain and pericardial/pleural effusion. Several triggers can be identified, related to implanted devices, biomaterial, and procedural aspects (prolonged hypotension, aneurysm thrombus manipulation, active fixation atrial leads, coronary microembolization, balloon dilatation/stent implantantation, contrast medium, coronary/myocardial microperforation). Nonetheless, these triggers share three main pathogenic pathways leading to SIRS clinical manifestations: leucocytes activation, endothelial injury/activation, and myocardial/pericardial injury. Therapy consists of non-steroidal agents, with corticosteroids as second-line treatment in non-responders. Although a benign evolution is reported after implantation of heart rhythm devices, PCI and EP, major adverse events may occur after EVAR/TEVAR and TAVI at short- and mid-term follow up.

Significance of Anti-Myosin Antibody Formation in Patients With Myocardial Infarction: A Prospective Observational Study

BACKGROUND

Anti-myosin antibodies (AMAs) are often formed in response to myocardial infarction (MI) and have been implicated in maladaptive cardiac remodelling. We aimed to: (1) compare AMA formation in patients with Non-ST-Elevation MI (NSTEMI) and ST-Elevation MI (STEMI); (2) evaluate factors predicting autoantibody formation; and, (3) explore their functional significance.

METHODS

Immunoglobulin M (IgM) and Immunoglobulin G (IgG) AMA titres were determined in serum samples collected at admission, 3 and 6 months post MI. The relationship between demographic and clinical data, and antibody formation, was investigated to determine factors predicting antibody formation and functional significance.

RESULTS

Forty-three (43) patients were consecutively recruited; 74.4% were positive for IgM at admission, compared with 23.3% for IgG. Mean IgG levels increased by 1.24% (±0.28) at 3 months, and 13.55% (±0.13) at 6 months post MI. Mean antibody levels were significantly higher in the NSTEMI cohort at both follow-up time points for IgG (p<0.001, p<0.0001), but not IgM (p=0.910, p=0.066). A moderately positive correlation between infarct size and increase in mean IgM concentration was observed at 3 months (r(98)=0.455; p=0.015). Anti-myosin antibody formation was not associated with an unfavourable outcome at follow-up.

CONCLUSIONS

Anti-myosin antibodies are formed in a significant proportion of patients following MI, particularly among those with NSTEMI. While IgM levels fall after infarction, IgG levels increase and persist beyond 6 months of follow-up. This raises the possibility that they may contribute to long-term myocardial damage and dysfunction. Future research should focus on the specific epitopes that are targeted by these antibodies, and their functional significance. This may result in the emergence of novel therapies to attenuate cardiac dysfunction in MI patients.

The adaptive immune response to cardiac injury-the true roadblock to effective regenerative therapies?

The regenerative capacity of adult human tissues and organs is limited, but recent developments have seen the advent of promising new technologies for regenerative therapy. The human heart is of particular interest for regenerative medicine, as cardiac tissue damage is repaired by the formation of rigid scar tissue, which causes inevitable structural changes and progressive functional decline leading to heart failure. Cardiac regenerative medicine aims to prevent scar formation or replace existing scars to halt or reverse adverse remodeling and therapeutic approaches include the use of biomaterials, gene therapies, delivery of growth factors, and (stem) cell therapies. Regenerative therapies, however, face significant obstacles in a hostile microenvironment. While the early immune response to a myocardial infarct is essential to ensure tissue integrity and to avoid fatal cardiac rupture, excessive activation of endogenous repair mechanisms may lead to ongoing inflammation, fibrosis, and sustained autoimmune-mediated tissue damage. Anti-cardiac autoreactivity of the adaptive immune system has been suggested to be involved in structural remodeling, functional decline, and the development of heart failure. It is, therefore, crucial to first understand the endogenous response to cardiac tissue damage and how to restore immune tolerance to cardiac tissue, before additional regenerative therapies can achieve their full potential.

Determinants of the postpericardiotomy syndrome: a systematic review

BACKGROUND

Postpericardiotomy syndrome (PPS) is a common complication following cardiac surgery; however, the exact pathogenesis remains uncertain. Identifying risk factors of PPS might help to better understand the syndrome. The aim of this study was to provide an overview of existing literature around determinants of PPS in adult cardiac surgery patients.

MATERIAL AND METHODS

Two independent investigators performed a systematic search in MEDLINE, EMBASE and the Cochrane Central Register. The search aimed to identify studies published between January 1950 and December 2015, in which determinants of PPS were reported.

RESULTS

A total of 19 studies met the selection criteria. In these studies, 14 different definitions of PPS were used. The median incidence of PPS was 16%. After quality assessment, seven studies were considered eligible for this review. Lower preoperative interleukin-8 levels and higher postoperative complement conversion products were associated with a higher risk of PPS. Among other clinical factors, a lower age, transfusion of red blood cells and lower preoperative platelet and haemoglobin levels were associated with a higher risk of PPS. Colchicine use decreased the risk of PPS.

CONCLUSION

We found that both the inflammatory response and perioperative bleeding and coagulation may play a role in the development of PPS, suggesting a multifactorial aetiology of the syndrome. Due to a lack of a uniform definition of PPS in the past, study comparability was poor across the studies.

Extracellular Actin in Health and Disease

This review considers the functions of extracellular actin - cell surface bound, associated with extracellular matrix, or freely circulating. The role of this protein in different pathological processes is analyzed: its toxic effects and involvement in autoimmune diseases as an autoantigen. The extracellular actin clearance system and its role in protection against the negative effects of actin are characterized. Levels of free-circulating actin, anti-actin immunoglobulins, and components of the actin clearance system as prognostic biomarkers for different diseases are reviewed. Experimental approaches to protection against excessive amounts of free-circulating F-actin are discussed.

The role of anti-myosin antibodies in perpetuating cardiac damage following myocardial infarction

Recent improvements in the medical and surgical management of myocardial infarction mean that many patients are now surviving with greater impairment of cardiac function. Despite appropriate management, some of these patients subsequently develop pathological ventricular remodelling, which compounds their contractile dysfunction and can lead to congestive cardiac failure (CCF). The pathophysiological mechanism underpinning this process remains incompletely understood. One hypothesis suggests that a post-infarction autoimmune response, directed against constituents of cardiac myocytes, including cardiac myosin, may make an important contribution. Our review summarises the current literature related to the formation and clinical relevance of anti-myosin antibodies (AMAs) in patients with myocardial infarction. This discussion is supplemented with reference to a number of important animal studies, which provide evidence of the potential mechanisms underlying AMA formation and autoantibody mediated cardiac dysfunction.

Inhibition of dipeptidyl peptidase-IV enzyme activity protects against myocardial ischemia-reperfusion injury in rats

Background

We investigated whether attenuating dipeptidyl peptidase-IV (DPP4) enzyme activity protected rat heart from ischemia-reperfusion (IR) injury (40-min left anterior descending coronary artery ligation followed by 72 h reperfusion).

Methods and results

Adult male Fischer 344 rats (n = 24) were equally divided into sham-control (WT-SC), WT-IR, and WT-IR-Sita (oral sitagliptin 400 mg/kg/day for 3 days) groups, whereas adult male DPP4-deficiency (DPP4^D) rats (n = 16) were equally divided into DPP4^D-SC and DPP4^D-IR groups. Animals were sacrificed at 72 h after reperfusion with collection of heart specimens. Infarct area (H&E), collagen deposition (Sirius-red stain), fibrotic area (Masson's trichrome), and fluorescent-ROS intensity (H₂DCFDA-labeling myocardium) of left ventricle were significantly higher in WT-IR than those in other groups, significantly higher in WT-IR-Sita and DPP4^D-IR groups than in WT-SC and DPP4^D-SC groups (all p < 0.001), but there was no difference between the latter two groups. Protein expressions of oxidative stress (oxidized protein), reactive oxygen species (NOX-1, NOX-2), inflammation (TNF-α, NF-κB, MMP-9, VCAM-1), apoptosis (mitochondrial Bax, cleaved caspase-3 and PARP), myocardial damage markers (cytosolic cytochrome-C, γ-H2AX), and number of inflammatory cells (CD14+, CD68+, CD40+ cells) showed a pattern identical to that of histological changes among all groups (all p < 0.005), whereas markers of anti-apoptosis (Bcl-2) and mitochondrial integrity (mitochondrial cytochrome-C) as well as left ventricular ejection fraction showed an opposite pattern (all p < 0.001). Protein expressions of anti-oxidants (HO-1, NQO-1), angiogenesis factors (SDF-1α, CXCR4), and glycogen-like-peptide-1-receptor were significantly higher inWT-IR-Sita and DPP4^D-IR than those in other groups (all p < 0.001).

Conclusion

Abrogation of DPP4 activity protects against myocardial IR injury and preserved heart function.

Combination of cilostazol and clopidogrel attenuates rat critical limb ischemia

BACKGROUND AND AIM

Procedural failure and untoward clinical outcomes after surgery remain problematic in critical limb ischemia (CLI) patients. This study tested a clopidogrel-cilostazol combination treatment compared with either treatment alone in attenuating CLI and improving CLI-region blood flow in rats.

METHODS

Male Sprague-Dawley rats (n = 40) were equally divided into five groups: control, CLI induction only, CL I + cilostazol (12.0 mg/day/kg), CLI + clopidogrel (8.0 mg/kg/day) and CLI + combined cilostazol-clopidogrel. After treatment for 21 days, Laser Doppler imaging was performed.

RESULTS

On day 21, the untreated CLI group had the lowest ratio of ischemic/normal blood flow (p < 0.001). Inflammation measured by VCAM-1 protein expression; oxidative stress; PAI-1, MMP-9 and TNF-α mRNA expressions; and immunofluorescence staining (IF) of CD68+ cells was lower with combined treatment than with the other treatments, and lower in the two single-treatment groups than the untreated CLI group (all p < 0.01). Anti-inflammatory mRNA expression of interleukin-10, and eNOS showed a reverse pattern among these groups. Apoptosis measured by Bax, caspase-3 and PARP; and muscle damage measured by cytosolic cytochrome-C, and serum and muscle micro-RNA-206 were all lowest with combination treatment, and the two single-treatment groups showed lower values than the untreated group (all p < 0.001). Angiogenesis measured by eNOS, IF staining of CD31+ and vWF + cells; and number of vessels in CLI region were highest with combination treatment and higher in the single-treatment groups than the untreated group (all p < 0.001).

CONCLUSION

Combined cilostazol-clopidogrel therapy is superior to either agent alone in improving ischemia in rodent CLI.

Transient reduction and activation of circulating dendritic cells in patients with acute myocardial infarction

BACKGROUND

Dendritic cells (DCs) are highly potent professional antigen-presenting cells that play a central role in initiating the primary immune response. Accumulating evidence suggests that immune-mediated inflammation plays an important role in the pathophysiology of AMI, but the mechanism that triggers such immune responses is unknown.

METHODS

Using multi-color flow-cytometry, we determined the numbers of circulating myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in patients with AMI (n = 26) or stable angina pectoris (SAP) (n = 19), and in age-matched control subjects (n = 19). The DC activation markers CD40 and CD83 were also measured.

RESULTS

On admission, circulating mDC and pDC counts were significantly lower in AMI patients compared to control subjects and SAP patients (mDC, P < 0.01; pDC, P < 0.05). The activation markers of mDCs in AMI patients were significantly higher and returned to the levels of control subjects or SAP patients 3 days after AMI (mDC, P < 0.05; pDC, P < 0.05). Reductions of circulating mDC and pDC numbers were restored 7 days after the onset of AMI. Furthermore, we found that the recovery of the circulating DC numbers 14 days after AMI was correlated with the alterations of creatine kinase-MB (CK-MB) (mDC, r = 0.48, P < 0.05; pDC, r=0.52, P < 0.01) and brain natriuretic peptide (BNP) (mDC, r = 0.53, P < 0.01; pDC, r = 0.51, P < 0.01).

CONCLUSION

Our findings suggest that the transient reduction and activation of circulating DCs may play important roles in the pathophysiology of myocardial injury after AMI.

Intra-coronary administration of tacrolimus markedly attenuates infarct size and preserves heart function in porcine myocardial infarction

Background

We test the hypothesis that intra-coronary tacrolimus administration can limit infarct size and preserve left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI) through ligating left anterior descending coronary artery (LAD) in mini-pigs.

Methods

Twelve male mini-pigs were randomized into AMI-saline (MI-only) group and AMI-tacrolimus (MI-Tac) group that received intra-coronary saline (3.0 mL) and tacrolimus (0.5 mg in 2.5 mL saline) injection, respectively, beyond site of ligation 30 minutes after LAD occlusion.

Results

Larger infarct area was noted in MI-only group (p < 0.001). Inflammatory biomarkers at protein [oxidative stress, tumor necrotic factor-α, nuclear factor-κB], gene (matrix metalloproteinase-9, plasminogen activator inhibitor-1), and cellular (CD40+, CD68+ inflammatory cells) levels were remarkably higher in MI-only animals (p < 0.01). Conversely, anti-inflammatory biomarkers at gene level (Interleukin-10), gene and protein level (endothelial nitric oxide synthase), and anti-oxidant biomarkers at both gene and protein levels [heme oxygenase 1, NAD(P)H:quinone oxidoreductase] were lower in MI-only group (p < 0.01). Number of apoptotic nuclei and apoptotic biomarkers expressions at gene and protein levels (Bax, caspase 3) were notably higher, whereas anti-apoptotic biomarkers at gene and protein levels (Bcl-2), LVEF, and fractional shortening were markedly lower in MI-only group (p < 0.001).

Conclusion

Intra-coronary administration of tacrolimus significantly attenuated infarct size and preserved LV function.

Recruitment of circulating dendritic cell precursors into the infarcted myocardium and pro-inflammatory response in acute myocardial infarction

DC (dendritic cells) play an important role in the immune system. They invade peripheral tissues to detect harmful antigens, inducing a local immune response. Studies suggest that DCPs (dendritic cell precursors) might be reduced in AMI (acute myocardial infarction); however, the reason for their reduction is unknown yet. In the present study, circulating mDCPs (myeloid DCPs), pDCPs (plasmacytoid DCPs), tDCPs (total DCPs) and serum levels of TNFα (tumour necrosis factor α), IL (interleukin)-2, -4, -5, -6, -10 and -12 were analysed by flow cytometry in blood of patients with NSTEMI [non-STEMI (ST-segment elevation myocardial infarction)] (n=44) and STEMI (n=34) compared with controls with excluded CAD (coronary artery disease) (n=45). Post-mortem myocardial specimens of patients with AMI (n=12) and healthy myocardium of accident victims (n=10) were immunostained for mDCs (myeloid dendritic cells) T-cells and macrophages. Compared with controls, in patients with AMI a significant decrease in circulating mDCPs, pDCPs and tDCPs was observed (each P<0.0001). The extent of the decrease was higher in STEMI than NSTEMI patients. Serum levels were significantly higher in patients with AMI compared with controls for IL-6, -10, -12 and TNFα (each P<0.03). Immunostaining revealed significantly higher number of DCs, T-cells and macrophages (each P<0.002) in infarcted than control myocardium. We show that circulating DCPs are significantly reduced in AMI, with a pronounced reduction in STEMI patients. This was accompanied by a significant increase of inflammatory serum cytokines in patients with AMI. Immunohistochemical analysis unravelled that the reduction of circulating DCPs might be due to recruitment into the infarcted myocardium.

Postpericardial injury syndrome: an autoimmune phenomenon

Postpericardial injury syndrome (PPIS) is defined as pericarditis or pericardial effusion that results from recent or earlier injury of the pericardium. The clinical features of this syndrome include fever, leukocytosis, and elevated erythrocyte sedimentation rate. Recent studies have established a connection between this clinical presentation and an underlying autoimmune process. The role of the humoral immune response is well established regarding the pathogenesis of PPIS with elevated titers of different antibodies and immune complexes in the circulation correlating with disease activity. Nevertheless, cell-mediated response by different subgroups of T lymphocyte has a significant importance with direct infiltration of pericardial tissue and fluids. The diagnosis of PPIS is still challenging. A strong connection between specific serological immunological markers and the disease would be of great value in diagnosis and treatment.

Postcardiac injury syndrome complicating radiofrequency ablation of the atrioventricular node

Radiofrequency ablation, which is increasingly used in the treatment of cardiac arrhythmia, can be complicated with pericardial effusion and one case of Dressler's syndrome has already been reported after an atrioventricular pathway ablation. This case reports a second case complicating an atrioventricular node radiofrequency ablation procedure.

Differential effects of GM-CSF and G-CSF on infiltration of dendritic cells during early left ventricular remodeling after myocardial infarction

Several lines of evidence suggest that the immune activation after myocardial infarction (MI) induces secondary myocardial injury. Although dendritic cells (DC) are potent regulators of immunity, their role in MI is still undetermined. We investigated the effect of DC modulation by CSF on left ventricular (LV) remodeling after MI. MI was induced by ligation of the left coronary artery in male Wistar rats. G-CSF (20 microg/kg/day, MI-G, n = 33), a GM-CSF inducer (romurtide, 200 microg/kg/day, MI-GM, n = 28), or saline (MI-C, n = 55) was administered for 7 days. On day 14, MI-G animals had higher LV max dP/dt and smaller LV dimensions, whereas MI-GM animals had lower LV max dP/dt and larger LV dimensions than did MI-C animals, despite similar infarct size. In MI-C, OX62(+) DC infiltrated the infarcted and border areas, peaking on day 7. Bromodeoxyuridine-positive DC were observed in the border area during convalescence. Infiltration by DC was decreased in MI-G animals and increased in MI-GM animals compared with MI-C (p < 0.05). In the infarcted area, the heat shock protein 70, TLR2 and TLR4, and IFN-gamma expression were reduced in MI-G, but increased in MI-GM in comparison with those in MI-C animals. IL-10 expression was higher in MI-G and lower in MI-GM than in MI-C animals. In conclusion, G-CSF improves and GM-CSF exacerbates early postinfarction LV remodeling in association with modulation of DC infiltration. Suppression of DC-mediated immunity could be a new strategy for the treatment of LV remodeling after MI.

Time course of plasma gelsolin concentrations during severe sepsis in critically ill surgical patients

Introduction

Gelsolin is an actin-binding plasma protein that is part of an 'actin-scavenging' system. Studies suggest that plasma gelsolin may play a crucial role in the pathophysiology of sepsis. Little is known about the course of plasma gelsolin levels over time in patients with severe sepsis. The aim of the study was to investigate plasma gelsolin levels in severe septic patients and to determine whether these levels predict the severity or clinical outcome of severe sepsis.

Methods

Ninety-one patients who were diagnosed with severe sepsis at admission to a surgical intensive care unit were enrolled, and admission plasma gelsolin levels were recorded. Plasma gelsolin levels were recorded daily in 23 of these patients. Daily plasma gelsolin levels were recorded in an additional 15 nonseptic critically ill patients. Fifteen volunteers served as healthy control individuals. Plasma gelsolin levels were measured using an enzyme-linked immunosorbent assay. Concentrations of IL-6, IL-10 and tumour necrosis factor (TNF)-α were also measured on intensive care unit admission.

Results

The admission gelsolin levels were significantly decreased in severe sepsis (20.6 ± 11.7 mg/l) compared with nonseptic critically ill patients (52.3 ± 20.3 mg/l; P < 0.001) and healthy control individuals (126.8 ± 32.0 mg/l; P < 0.001). Severe septic patients had increased IL-6 levels compared with nonseptic critically ill patients (20.0 ± 10.7 pg/ml versus 11.4 ± 13.9 pg/ml; P = 0.048), whereas no significant difference in IL-10 or TNF-α levels was observed (IL-10: 97.9 ± 181.5 pg/ml versus 47.4 ± 91.5 pg/ml, respectively [P = 0.425]; TNF-α: 14.2 ± 13.9 pg/ml versus 6.9 ± 5.3 pg/ml, respectively; P = 0.132). Survivors of severe sepsis exhibited substantial recovery of their depressed plasma gelsolin levels, whereas gelsolin levels in nonsurvivors remained at or below their depleted admission levels.

Conclusion

Plasma gelsolin may be a valuable marker for severe sepsis. Recovery of depleted plasma gelsolin levels correlated with clinical improvement. The prognostic role of plasma gelsolin in critical illness requires further investigation in a large cohort.

Cytotoxic T Lymphocyte Antigen 4 Gene Polymorphism Associated With ST-Segment Elevation Acute Myocardial Infarction

BACKGROUND

Cytotoxic T lymphocyte antigen 4 (CTLA-4) is a particularly important molecule in down-regulating T-cell expansion and cytokine production. The purpose of the present study was to determine the frequency distribution of an A/G single nucleotide polymorphism at position 49 in exon 1 of the CTLA-4 gene, which may be a functional related-genetic risk marker for the development of ST-segment elevation (ST-se) acute myocardial infarction (AMI).

METHODS AND RESULTS

A total of 503 consecutive patients, consisting of 250 ST-se AMI patients undergoing primary coronary angioplasty (group 1), 203 angina pectoris patients undergoing elective coronary angioplasty (group 2) and 50 patients with chest pain and normal coronary angiographic findings (group 3), were enrolled in the present study. The frequency of the G/G genotype was significantly higher in group 1 (53.2%) than in groups 2 (33.0%) and 3 (36.0%) (p=0.0005). In group 1, patients with a G/G genotype had significantly higher levels of high-sensitivity C-reactive protein and white blood cell counts, and much higher incidences of multi-vessel disease, greater lesion lengths, advanced congestive heart failure (>or=class 3) and 30-day mortality, than patients with G/A or A/A genotypes (p values<0.05 in all cases). Multivariate analysis of the enrolled baseline variables (age, gender, diabetes mellitus, smoking, hypertension and hypercholesterolemia) and the genotypes (G/G, A/G and A/A) demonstrated that G/G genotype is the only independent predictor of development of AMI (p<0.0001).

CONCLUSION

The G/G genotype polymorphism of the CTLA-4 gene is associated with increased risk of AMI.

Autoimmunity in myocardial infarction

Myocardial infarction is associated with an immune response. Physiological inflammation response causes self-repair and protection, while pathological autoimmune response leads to ventricular remodeling and heart failure. Laying emphasis on regulating the immune function may become a new target for the prevention of heart failure after myocardial infarction. This review focuses on the mechanism of immune-mediated ventricular remodeling and the immune therapy after myocardial infarction.

The Spectrum of Pleural Effusions After Coronary Artery Bypass Grafting Surgery

Pleural effusions are common after coronary artery bypass grafting (CABG) surgery and can be categorized by time intervals: perioperative (within the first week), early (within 1 month), late (2-12 months), or persistent (after 6 months). The perioperative effusions are usually attributable to diaphragm dysfunction or internal mammary artery harvesting and are typically self-limited. Early effusions are usually attributable to postcardiac injury syndrome and may require corticosteroid treatment. Although late effusions can have multiple causes, persistent effusions are attributable to trapped lung and often require decortication. Diagnostic thoracentesis should be performed for patients with large symptomatic pleural effusions or fever after CABG surgery. The range of management includes observation, therapeutic thoracentesis, corticosteroids, or decortication depending on the cause and course of the effusion.

Cytotoxic T lymphocytes are activated following myocardial infarction and can recognize and kill healthy myocytes in vitro

The damage of myocardial infarction (MI) is often progressive. A possible mechanism for subsequent myocardial damage and heart failure after MI is immune response against cardiac self-antigens. The purpose of our study was to test the hypothesis that cytotoxic T lymphocytes are activated following acute MI and may have a role in producing further myocardial damage. Rats were allocated into three experimental groups: acute MI, Sham MI and non-operated control. One, two and three weeks after surgery, lymphocytes were obtained from rat spleens and incubated with neonatal cardiac myocytes. Lymphocyte proliferation was assessed by a thymidine incorporation assay and calculated as proliferation index (PI). Myocyte destruction was measured by a crystal-violet staining assay and expressed as percentage of cell destruction. Proliferation index was significantly higher among lymphocytes obtained from MI animals (44. 3+/-5.8 and 44.9+/-5.1, at 2 and 3 weeks after MI, respectively) than sham MI (29.3+/-5.3, 27.1+/-4.7) (P<0.05) or control animals (17.1+/-2.5, 16.2+/-2.8) (P=0.03). Cytotoxic activity of the MI lymphocytes against the cultured cardiomyocytes was significantly higher 2 and 3 weeks after MI, (36.4+/-7.3%, 69.3+/-4.9%) compared to sham MI (17.9+/-3.14%, 36.6+/-5.3%) (P<0.001) and control animals respectively (13.3+/-5.4%, 17.4+/-6.1%) (P<0.001). The cytotoxic activity against healthy cardiomyocytes was myocyte-specific, induced by CD8 lymphocytes and major-histocompatibility complex (MHC) restricted. Cytotoxic T lymphocytes (CD8) are activated following MI and can recognize and kill normal cardiomyocytes in vitro. The newly described pathophysiological insights may provide novel oportunities to prevent death of non-ischemic cardiomyocytes and heart failure following myocardial infarction.

Post-Myocardial Infarction Pericarditis

Post-myocardial infarction pericarditis occurs in approximately 5% to 6% of patients who receive thrombolytic agents. It should be suspected in any patient with pleuropericardial pain. A pericardial friction rub may or may not be present. Differentiation of pericarditis from recurrent angina may be difficult, but a careful history and evaluation of serial electrocardiograms can help distinguish the two entities. Dressler's syndrome, pericarditis that occurs at least 1 week following myocardial infarction, is now exceedingly rare. Most cases of pericarditis have a benign course; however, because pericarditis is associated with larger infarcts, overall long-term mortality rate is increased. Rare complications include hemopericardium, cardiac tamponade, and constrictive pericarditis. Therapy is directed toward relief of pain, which usually responds well to nonsteroidal anti- inflammatory agents (eg, aspirin or ibuprofen).

Relationship of admission plasma gelsolin levels to clinical outcomes in patients after major trauma

Actin-scavenging proteins, e.g., plasma gelsolin, counteract the pathophysiological consequences of actin leaked into the circulation from dying cells, but the capacity of this defense system can be overwhelmed by massive tissue injury. We examined the prognostic implications of plasma gelsolin levels obtained near the time of admission to our level I Trauma Unit on the subsequent clinical course in a group of patients with severe traumatic injuries. Blood samples were obtained from 13 patients shortly after major trauma and 11 healthy volunteers who served as the control group. Plasma gelsolin levels were assayed by quantitative Western blotting. Duration of mechanical ventilation, stay in the Trauma Intensive Care Unit, and development of acute respiratory distress syndrome (ARDS) were measured as clinical outcomes reflecting the complexity of the hospital course. Subsequently, we evaluated an additional 52 patients after major and minor trauma to extend our earlier observations. Plasma gelsolin concentrations were significantly lower in our 13 original patients compared with healthy controls. Levels below 250 mg/L (> 2 standard deviations below the mean of the control group) were associated with prolonged mechanical ventilation and a stay in the intensive care unit >/= 13 days. Both patients whose gelsolin level was < 100 mg/L in this first series developed ARDS. Including all 65 patients, 6 of the 10 patients who developed ARDS had admission gelsolin levels less than 250 mg/L, compared with only 7 of the 55 patients without ARDS (p = 0.0028). The mean gelsolin levels were 193 and 400 mg/L in patients with and without ARDS, respectively (p < 0.0001) and 398 mg/L in survivors versus 259 mg/L for patients who expired (p < 0.0001). Ten of the 13 patients (77%) with gelsolin levels at the time of admission more than 2 SD below the control mean had "bad outcomes," defined as mechanical ventilation for >/= 13 days in the Trauma Intensive Unit, ARDS, and/or death. Plasma gelsolin levels appear to be an early prognostic marker in patients experiencing major trauma. Whether circulating gelsolin serves a biologically vital function or is simply depleted after massive trauma cannot be determined from our study. The potential therapeutic benefits of infusions of recombinant human plasma gelsolin for patients in whom multiorgan dysfunction commonly follows a serious but self-limited insult have not yet been investigated.

Characterization of anti-heart antibodies in mice after infection with coxsackie B3 virus

Coxsackie virus B3 (CVB3) infection results in a marked inflammatory response and the production of autoantibodies to cardiac antigens, with cardiac myosin heavy chain documented to be the most immunogenic antigen. The present study investigated the temporal appearance of anti-heart antibodies in mice after mock infection or infection with an attenuated variant of CVB3 or wildtype CVB3 by SDS-PAGE and Western blotting. Further characterization of the autoantigens was carried out using 2D electrophoresis followed by Western blotting. Mice infected with wildtype CVB3 demonstrated high levels of IgG anti-heart antibodies, reacting predominantly with myosin heavy chain but also with numerous other myocardial proteins. Significant increases in anti-myosin heavy chain, anti-actin, and anti-tropomyosin antibodies were seen in wildtype-infected mice as early as day 7 postinfection compared to those mice that were mock infected or infected with attenuated virus. Characterization of other antigens revealed novel reactivities against myosin subfragments, heat shock proteins, and desmin and its subfragments.

Postcardiac injury syndrome. An immunologic pleural fluid analysis

The postcardiac injury syndrome (PCIS) is characterized by inflammation of the pericardium, pleura, and pulmonary parenchyma following a variety of cardiac injuries. Although it has been clinically recognized for decades, confirmation of the syndrome has been problematic owing to lack of a sufficiently diagnostic test. Previously, we have reported pleural fluid characteristics which help to exclude other diagnoses that may mimic the syndrome. We describe the first immunologic assessment, including antimyocardial antibody testing, of pleural fluid from a patient with PCIS which supports a local immunologic mechanism in the pathogenesis of the syndrome. These results support the important role of pleural fluid analysis in the diagnosis of PCIS.

Autoimmunity to alpha myosin in a subset of patients with idiopathic dilated cardiomyopathy

OBJECTIVE

To use an enzyme linked immunoassay (ELISA) technique to assess frequency and disease specificity of anti-alpha-myosin antibodies in patients with dilated cardiomyopathy and their relatives.

METHODS

Evaluation was performed on sera (dilution 1/320) from 123 consecutive patients with dilated cardiomyopathy (WHO criteria) (age 42 (SD 14) years), 252 of their relatives (35 (17) years), 203 healthy controls (45 (16) years), and 92 patients with ischaemic heart disease (63 (11) years).

RESULTS

Abnormal antibody levels were commoner in patients with dilated cardiomyopathy (25, 20%) than in ischaemic heart disease (4, 4%), or normal controls (4, 2%, P = 0.001). Forty one (16%) of the relatives had abnormal results compared to the controls (4, 2%, P < 0.001) and antibodies were detected in 20 (38%) of pedigrees. Relatives from non-familial kindreds had higher antibody levels than those with familial disease (P << 0.001), and higher antibody levels were identified in 53 relatives of probands who had abnormal results compared to 116 relatives for whom the proband had a normal result (0.37 (SEM 0.02) v 0.22 (0.01); P < 0.001).

CONCLUSIONS

The finding of anti-alpha-myosin antibodies in 20% of patients with dilated cardiomyopathy, in 16% of their asymptomatic relatives, and in 38% of families (particularly those with non-familial disease and where proband also had an abnormal result) provides additional evidence for autoimmunity against alpha myosin in a subset of patients.

Non-muscle myosin as target antigen for human autoantibodies in patients with hepatitis C virus-associated chronic liver diseases

Three patients with hepatitis C virus (HCV)-related chronic liver disease were shown to have autoantibodies strongly reacting with cytoskeletal fibres of non-muscle cells. The heavy chain of non-muscle myosin microfilament was the main target for those autoantibodies, as determined by (i) cell and tissue immunofluorescence studies showing colocalization with an anti-myosin antibody prototype; (ii) primary reactivity in immunoblotting with a 200-kD protein, using either MOLT-4 cells, human platelets, or affinity-purified non-muscle myosin as antigen extract; and (iii) immunoblotting of similar immunoreactive fragments in papain-digested MOLT-4 cell extracts, by using those human sera and antibody prototype. Autoantibodies to non-muscle myosin heavy chain were not previously reported in patients with chronic liver diseases, especially in those associated with HCV infection.

Antibody-mediated autoimmune myocarditis depends on genetically determined target organ sensitivity

Injury to cardiac myocytes often leads to the production of anti-myosin antibodies. While these antibodies are a marker of myocardial injury, their contribution to pathogenesis in diseases such as autoimmune myocarditis or rheumatic fever is much less clear. We demonstrate in this report that monoclonal anti-myosin antibodies can mediate myocarditis in a susceptible mouse strain. Additionally, we show disease susceptibility depends on the presence of myosin or a myosin-like molecule in cardiac extracellular matrix. This study demonstrates that susceptibility to autoimmune heart disease depends not only on the activation of self-reactive lymphocytes but also on genetically determined target organ sensitivity to autoantibodies.

Relationship between the degree of injury at operation and the change in antimyosin antibody titer in the postpericardiotomy syndrome

Successive measurements of cardiac myosin light chain I (MLC), creatine kinase isoenzyme MB (CKMB), and the titer of antimyosin antibody (AMA) were performed prospectively in 19 patients following open heart surgery. Seven of these patients showed the postpericardiotomy syndrome (PPS). No differences in serum concentrations of MLC or CKMB were observed between the patients with and without PPS, and all patients in both groups had abnormal MLC values after surgery. However, only patients with PPS had significantly elevated AMA titers. The maximum AMA titer was significantly correlated with the severity of the effusion. These data suggest that PPS is unrelated to the severity of myocardial injury during operation. Furthermore, the AMA titer may be useful as one of the indicators for determining the patient's clinical condition.

Acute rise in serum immunoglobulin E concentration in pulmonary thromboembolism

Events mediated by immunoglobulin E (IgE) may be related to platelet activation and aggregation, and there may be an association between IgE and pulmonary thromboembolism (PTE). Fourteen patients with PTE were studied with regard to serum concentrations of IgE, IgA, IgG, IgM, fibrinogen, and D-dimer and with regard to blood neutrophil, lymphocyte, platelet, and eosinophil counts during acute and recovery phases. The serum IgE concentration increased during the acute phase to 402 +/- 310 IU/ml and decreased afterwards in all patients. The increase in serum IgE concentration lagged a few days behind that of the serum D-dimer concentration, indicating later IgE production than thrombus formation and lysis. Infarction and pleural fluid accumulation developed in patients with a high initial serum IgE concentration. These results indicated a relationship between serum IgE concentration and the pathophysiology of PTE. Serum IgE may be an indicator of the severity of PTE and provide insight into its pathogenesis, thereby facilitating the diagnosis of PTE.

The macroenzymes: a clinical review

Macroenzymes are serum enzymes that have a higher molecular mass than the corresponding enzyme normally found in serum under physiologic or pathophysiologic conditions. Although no evidence convincingly indicates that macroenzymes cause disease or necessitate treatment, some patients with immunoglobulin-complexed enzyme disorders have previously been reported to have associated autoimmune diseases or malignant lesions. To address this issue, we reviewed the medical records of 42 patients in whom a macroenzyme had been detected during assessment at the Mayo Clinic between 1986 and 1990. Of these 42 patients, 21 had macro-creatine kinase, 10 had macro-lactate dehydrogenase, 6 had macro-aspartate aminotransferase, and 5 had macroamylase in the serum. Although the study group did not include all Mayo patients with this phenomenon, it represented a sufficient sample size to determine retrospectively whether specific dismissal diagnoses were present concurrently. The most common findings in this group of patients with macroenzymes were (1) advanced age (except for those with macro-aspartate aminotransferase), (2) cardiovascular disease (probably due to sampling bias), (3) malignant lesions (particularly in those with macro-creatine kinase), and (4) rheumatologic disease (in those with macro-lactate dehydrogenase). The immunoglobulin-complexed enzyme disorders are characterized by increased total serum enzyme levels that are often isolated and persistent. Physicians should be aware of the presence of macroenzymes so that invasive or costly procedures are not undertaken unnecessarily to determine the cause of increased serum enzyme levels.