Pericardial Fluid Accumulates microRNAs That Regulate Heart Fibrosis after Myocardial Infarction.

Pericardial fluid (PF) has been suggested as a reservoir of molecular targets that can be modulated for efficient repair after myocardial infarction (MI). Here, we set out to address the content of this biofluid after MI, namely in terms of microRNAs (miRs) that are important modulators of the cardiac pathological response. PF was collected during coronary artery bypass grafting (CABG) from two MI cohorts, patients with non-ST-segment elevation MI (NSTEMI) and patients with ST-segment elevation MI (STEMI), and a control group composed of patients with stable angina and without previous history of MI. The PF miR content was analyzed by small RNA sequencing, and its biological effect was assessed on human cardiac fibroblasts. PF accumulates fibrotic and inflammatory molecules in STEMI patients, namely causing the soluble suppression of tumorigenicity 2 (ST-2), which inversely correlates with the left ventricle ejection fraction. Although the PF of the three patient groups induce similar levels of fibroblast-to-myofibroblast activation in vitro, RNA sequencing revealed that PF from STEMI patients is particularly enriched not only in pro-fibrotic miRs but also anti-fibrotic miRs. Among those, miR-22-3p was herein found to inhibit TGF-ß-induced human cardiac fibroblast activation in vitro. PF constitutes an attractive source for screening diagnostic/prognostic miRs and for unveiling novel therapeutic targets in cardiac fibrosis.

Detection of new metabolites of risperidone in the solid tissues and body fluids obtained from two cadavers by high resolution tandem mass spectrometry.

Risperidone (Ris) is a second-generation antipsychotic that belongs to the chemical class of benzisoxazole derivatives. 9-Hydroxy (9OH-) Ris is well known among the six reported metabolites of Ris and had been examined using not only blood but also other matrices, but the other five metabolites reported such as benzisoxazole ring-cleaved Ris (c-Ris) and c-9OH-Ris had been detected only in blood, urine and feces. In the present work, large peaks of c-Ris and c-9OH-Ris were detected in the liver, kidney, cerebrum, blood, pericardial fluid, bile and urine obtained from two cadavers. There is a potential that c-Ris and c-9OH-Ris will be good markers to prove Ris consumption in forensic toxicology cases. For example, the peak ratios of c-Ris against the parent Ris in the kidney and blood were as high as 3.9 and 3.6 in cadaver 1; and 7.0 and 7.9 in cadaver 2, respectively. In addition to the previously reported six metabolites, five new metabolites such as dehydrogenated-Ris, 7-keto-Ris and three benzisoxazole ring-cleaved metabolites were disclosed in the present work, and the pathways for the totally eleven metabolites detected in human solid tissues and body fluids have also been proposed, because such pathways were neither reported nor discussed previously.

Pericardial fluid troponin in cardiac surgery.

BACKGROUND AND OBJECTIVE: Pericardial Fluid (PF) is a rich reservoir of biologically active factors. Due to its proximity to the heart, the biochemical structure of PF may reflect the pathological changes in the cardiac interstitial environment. This manuscript aimed to determine whether the PF level of cardiac troponins changes in patients undergoing cardiac surgery. METHODS: This scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medline, EMBASE, Cochrane, ClinicalTrials.gov, and Google Scholar databases were electronically searched for primary studies using the keywords "pericardial fluid," "troponin," and "cardiac surgery." The primary outcome of interest was changes in troponin levels within the PF preoperatively and postoperatively. Secondary outcomes of interest included comparisons between troponin level changes in the PF compared to plasma. RESULTS: A total of 2901 manuscripts were screened through a title and abstract stage by two independent blinded reviewers. Of those, 2894 studies were excluded, and the remaining seven studies underwent a full-text review. Studies were excluded if they did not provide data or failed to meet inclusion criteria. Ultimately, six articles were included that discussed cardiac troponin levels within the PF in patients who had undergone cardiac surgery. Pericardial troponin concentration increased over time after surgery, and levels were significantly higher in PF compared to serum. All studies found that the type of operation did not affect these overall observations. CONCLUSION: Our review of the literature suggest that the PF level of cardiac troponins increases in patients undergoing cardiac surgery, irrespective of the procedure type. However, these changes' exact pattern and clinical significance remain undefined.

A native extracellular matrix material for tissue engineering applications: Characterization of pericardial fluid.

Tissue engineering applications are widely used to repair and regenerate damaged tissues and organs. A scaffold, which is an important component in tissue engineering, provides a 3D environment for cells. In this study, the usability of PF components for the production of an ideal scaffold was investigated. For this aim, pericardial fluid (PF) was harvested from the bovine heart, then its structure and components were characterized. The results of Raman spectroscopy analysis, histological staining, and scanning electron microscopy (SEM) shows that the pericardial fluid contains collagen type I and IV, elastin, fibrin, and glycosaminoglycan (GAG), which are native extracellular matrix (ECM) components. The results demonstrated that (i) PF contains native ECM proteins and GAG such as collagen types I, III, and IV, elastin, and fibrin. (ii) The PF is highly similar to the native ECM structure. (iii) PF can significantly contribute to many tissue engineering studies as a native ECM material to increase the biocompatibility of biomaterials and to several in vitro/in vivo cell culture studies. (iv) PF containing multiple ECM molecules, can be used alone or together with hyaluronic acid, poly(ethylene glycol) (PEG), alginate, chitosan, matrigel, and gelatin methacryloyl (GelMA) materials in bioprinting systems for eliminating the disadvantages of these materials.

Postmortem pericardial fluid sLOX-1 levels and LOX-1 immunostaining in forensic specimens: Relation to cause of death.

Lectin-like oxidized LDL receptor-1 (LOX-1) is the endothelial receptor for oxidized LDL. This receptor's extracellular domain is released into the blood as soluble LOX-1 (sLOX-1) and has been linked to ischemic heart disease (IHD), cerebrovascular diseases (CVDs), obesity, and diabetes. We recently reported that sLOX-1 fluid levels in postmortem pericardial fluid were comparable to clinical values in live patients and that significant increases in sLOX-1 were observed in patients with IHD. However, postmortem serum and urine sLOX-1 levels were higher than serum levels in living patients. Here, we conducted LOX-1 immunostaining in forensic specimens (aorta and heart) and evaluated pericardial fluid sLOX-1 in 221 medicolegal autopsy cases (67 IHD, 11 CVD, 17 inflammatory diseases, and 126 control cases) with a postmortem interval < 72 h to assess the diagnostic efficiency of postmortem pericardial fluid sLOX-1. Furthermore, we evaluated the relationships between pericardial fluid sLOX-1 and body mass index (BMI), blood HbA1c, serum C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-C), and low-density-lipoprotein cholesterol (LDL-C). LOX-1 immunostaining positivity was found in the aortic intima. Pericardial fluid sLOX-1 levels were considerably higher in patients with IHD and CVD. However, there were no significant differences in patients with inflammatory diseases and controls. No associations between pericardial fluid sLOX-1 and BMI, HbA1c, CRP, HDL-C, or LDL-C were found. These results indicate sLOX-1 utility in the postmortem diagnosis of IHD and CVD.

Exosomes Containing LINC00636 Inhibit MAPK1 through the miR-450a-2-3p Overexpression in Human Pericardial Fluid and Improve Cardiac Fibrosis in Patients with Atrial Fibrillation.

The purpose of this study was to investigate the regulatory mechanism of miR-450a-2-3p in myocardial fibrosis in patients with atrial fibrillation. For this purpose, the expression profile of GSE55296 was extracted from the GEO database, and differentially expressed lncRNAs were identified. Gene ontology analysis of the target genes of mir-450a-2-3p indicated that there was a regulatory relationship between LINC00636 and miR-450a-2-3p. Further, the expression levels of the analyzed RNAs were confirmed by RT-qPCR. TGF-ß1-induced cardiac fibroblasts (CFs) and human umbilical vein endothelial cells (HUVECs) were used to establish a myocardial fibrosis model and endothelium-mesenchymal transformation (EMT) model in vivo. We hypothesized that exosomes containing LINC00636 regulate the expression of miR-450a-2-3p. LINC00636 was positively correlated with the expression of miR-450a-2-3p. The overexpression of miR-450a-2-3p suppressed the MAPK1 expression in CFs, thereby inhibiting the expression of α-SMA, COL1, and COL3 and preventing CF proliferation. In HUVECs, the miR-450a-2-3p overexpression upregulated the expression of VE-Cadherin (VE-Cad) and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) by inhibiting the mitogen-activated protein kinase 1 (MAPK1) expression, whereas the expression levels of vimentin, COL1, and COL3 decreased. These results indicate that LINC00636, which is present in human pericardial fluid, is an antifibrotic molecule that inhibits MAPK1 through the miR-450a-2-3p overexpression and improves cardiac fibrosis in patients with atrial fibrillation.

Impact of pericardial fluid glucose level and computed tomography attenuation values on diagnosis of malignancy-related pericardial effusion.

BACKGROUND: We evaluated malignancy according to the characteristics of pericardial fluid in symptomatic Japanese patients undergoing pericardiocentesis and computed tomography (CT). METHODS: This was a retrospective, single-center, observational study of 125 symptomatic patients undergoing pericardiocentesis. The patients were classified into two groups: a malignancy group and a non-malignancy group, according to the primary disease and cytology of the pericardial effusion (PE). We compared the pericardial fluid sample and CT measurements between both groups. RESULTS: All patients were diagnosed as having exudative PE by Light's criteria. PE with malignant cells was demonstrated in 76.8% of the malignancy group patients. Pericardial to serum lactate dehydrogenase (LDH) ratio > 0.6, as one of Light's criteria, was associated with malignancy (p = 0.017). Lower serum brain natriuretic peptide (BNP) concentration was also associated with malignancy (BNP: 126.9 ± 89.8 pg/ml vs 409.2 ± 97.7 pg/ml, malignancy vs non-malignancy groups, respectively; p = 0.037). A significant difference was observed in pericardial fluid glucose level between the malignancy and non-malignancy groups (pericardial fluid glucose: 78.24 ± 48.29 mg/dl vs 98.41 ± 44.85, respectively; p = 0.048). Moreover, CT attenuation values (Hounsfield units (HU)) tended to be higher in the malignancy group vs the non-malignancy group (22.7 [interquartile range (IQR), 17.4-26.0] vs 17.4 [IQR, 13.7-26.4], respectively; p = 0.08). The sensitivity and specificity of pericardial fluid glucose level ≤ 70 mg/dl and CT attenuation values > 20 HU were 40.9% and 89.6%, respectively, in the malignancy group. The positive- and negative predictive values of pericardial fluid glucose level ≤ 70 mg/dl and CT attenuation values > 20 HU were 85.7% and 50.0%, respectively, in the malignancy group. Pericardial fluid glucose level ≤ 70 mg/dl and CT attenuation values > 20 HU were cutoff values associated with malignancy (p = 0.012). CONCLUSIONS: Lower pericardial fluid glucose level with higher CT attenuation values may suggest malignancy-related PE.

Local IGF Bioactivity Associates with High PAPP-A Activity in the Pericardial Cavity of Cardiovascular Disease Patients.

OBJECTIVE: Pregnancy-associated plasma protein-A (PAPP-A) has been suggested as a proatherogenic enzyme by its ability to locally increase insulin-like growth factor (IGF) activity through proteolytic cleavage of IGF binding protein-4 (IGFBP-4). Recently, stanniocalcin-2 (STC2) was discovered as an inhibitor of PAPP-A. This study aimed to investigate IGFBP-4, PAPP-A, and STC2 as local regulators of IGF bioactivity in the cardiac microenvironment by comparing levels in the pericardial fluid with those in the circulation of patients with cardiovascular disease. METHODS: Plasma and pericardial fluid were obtained from 39 patients undergoing elective cardiothoracic surgery, hereof 15 patients with type 2 diabetes. Concentrations of IGF-I, intact and fragmented IGFBP-4, PAPP-A, and STC2 were determined by immunoassays and IGF bioactivity by a cell-based assay. RESULTS: In pericardial fluid, the concentrations of total IGF-I, intact IGFBP-4, and STC2 were 72 ± 10%, 91 ± 5%, and 40 ± 24% lower than in plasma, while PAPP-A was 15 times more concentrated. The levels of the 2 IGFBP-4 fragments generated by PAPP-A and reflecting PAPP-A activity were elevated by more than 25%. IGF bioactivity was 62 ± 81% higher in the pericardial fluid than plasma. Moreover, pericardial fluid levels of both IGFBP-4 fragments correlated with the concentration of PAPP-A and with the bioactivity of IGF. All protein levels were similar in pericardial fluid from nondiabetic and diabetic subjects. CONCLUSIONS: PAPP-A increases IGF bioactivity by cleavage of IGFBP-4 in the pericardial cavity of cardiovascular disease patients. This study provides evidence for a distinct local activity of the IGF system, which may promote cardiac dysfunction and coronary atherosclerosis.

A Novel Bioanalytical Method for the Determination of Opioids in Blood and Pericardial Fluid.

Opioids are the drugs most commonly detected in overdose deaths and the second most consumed worldwide. An analytical methodology has been optimized and fully validated for the determination of codeine, morphine, 6-acetylmorphine, 6-acetylcodeine, oxycodone, oxymorphone and fentanyl in whole blood and pericardial fluid. The internal standards used were codeine-d3, morphine-d3, 6-acetylmorphine-d3 and fentanyl-d5. Before solid-phase extraction, volumes of 250 µL of blood and pericardial fluid were subjected to a protein precipitation (with 750 µL of ice-cold acetonitrile) and a microwave-induced oximation was performed using a solution of 1% aqueous hydroxylamine hydrochloride in phosphate-buffered saline (1:2, v/v). Finally, the dried extracts were further derivatized with a solution of n-methyl-n-(trimethylsilyl) trifluoroacetamide + 5% trimethylchlorosilane under microwave irradiation. The chromatographic analysis was carried out using gas chromatography-mass spectrometry operating in electron impact and selected ion monitoring mode. For all analytes, the method was linear between 5 and 1,000 ng/mL with determination coefficients (r2) >0.99. Depending on the analyte and matrix, the limit of detection varies between 3 and 4 ng/mL. Intra- and intermediate precision (<20%) and bias (±20%) were acceptable for all analytes in both matrices. The stability of the substances in the studied matrices was guaranteed, at least, 24 h in the autosampler, 4 h at room temperature and 30 days after three freeze/thaw cycles. This methodology was applied to real samples from the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

Comparison of C-reactive protein levels between antemortem serum and postmortem serum and pericardial fluid.

Biochemical markers undergo postmortem changes that complicate diagnostic measurement. C-reactive protein (CRP) is one marker that is known to be useful in postmortem specimens, with high levels reported in forensic cases of sepsis, trauma, and ketoacidosis. In the present study, we included 30 cases (17 males and 13 females) that underwent forensic autopsy within 80 h of death and had a CRP result from two postmortem specimens (serum from cardiac blood and pericardial fluid) and an emergency room specimen. Antemortem results were taken at a time near to cardiopulmonary arrest and the declaration of death. CRP levels in postmortem serum and pericardial fluid correlated with those in antemortem serum. Although no significant difference was observed between the antemortem and postmortem serum levels, the pericardial level was significantly low and five false negatives were observed. We conclude that postmortem serum is suitable for use in CRP measurement, and in cases with high antemortem CRP levels, postmortem pericardial fluid may be an appropriate alternative.

Diagnostic role of postmortem CK-MB in cardiac death: a systematic review and meta-analysis.

Biochemical analysis of creatine kinase MB (CK-MB), which is a biomarker of myocardial damage, is used as a potential adjunct test in clinical and forensic medicine. However, there is no previous meta-analysis that summarizes the diagnostic value of postmortem biochemical analysis of CK-MB in cardiac death. The purpose of this study was to perform a systematic literature review and meta-analysis of postmortem CK-MB in cardiac death for forensic work. Six online databases, including PubMed, Embase, Cochrane Library, the China National Knowledge Infrastructure (CNKI), the China Biomedical Literature Database (CBM), and Wanfang Data, were used to search for related studies. The quality of the included literature was assessed according to the Newcastle-Ottawa Quality Assessment Scale (NOS). The meta-analysis was performed by Review Manager version 5.3 software to investigate the diagnostic role of postmortem CK-MB in cardiac death, especially in myocardial infarction. Sixteen pieces of related literature were identified, all of which were considered high quality. The results of the meta-analysis revealed that the postmortem CK-MB level in the pericardial fluid was significantly higher in the cardiac death group with a standard mean difference (SMD) = 0.63, 95% confidence interval (CI) = 0.09~1.17, p = 0.02. This was also the result in the myocardial infarction group (SMD = 0.83, 95% CI = 0.10~1.56, p = 0.03). No significant difference in CK-MB was found in serum for cardiac death (SMD = -0.31, 95% CI = -0.85~0.24, p = 0.27) or myocardial infarction (SMD = -0.10, 95% CI = -0.69~0.49, p = 0.74). The postmortem biochemical analysis of CK-MB in the pericardial fluid can be used as an auxiliary method in the postmortem diagnosis of cardiac death, along with autopsy and histological investigation.

Postmortem urine concentration of N-terminal pro-brain natriuretic peptide in relation to the cause of death.

The utility of biochemical marker analysis in forensic autopsy cases is still uncertain due to the postmortem changes which they undergo. Thus, research is required to elucidate alternative samples and biochemical markers which are less affected by postmortem changes. Levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) are known to be elevated in congestive heart failure (CHF), acute myocardial infarction (AMI), and sepsis patients. Although NT-proBNP is reportedly excreted into the urine, no study has previously evaluated the diagnostic efficacy of urinary concentrations in a forensic setting. The aim of this study was to evaluate the diagnostic efficacy of NT-proBNP concentration in urine obtained postmortem in a series of forensic autopsy cases. METHODS: Urinary NT-proBNP was measured in 36 AMI, 10 CHF, and 19 sepsis cases, and in 124 control cases (all with postmortem interval [PMI]<72h). RESULTS: Urinary NT-proBNP was significantly higher in AMI, CHF, and sepsis cases than in control cases. Cut-off values for diagnosing AMI, CHF, and sepsis-related fatalities were 98 (sensitivity, 55.6 %; specificity, 73.4 %), 1050 (sensitivity, 80.0 %; specificity, 94.4 %), and 363pg/mL (sensitivity, 84.2 %; specificity, 85.5 %), respectively. Furthermore, we subdivided the control cases according to the death process as either acute death (87 cases) or prolonged death cases (37 cases). Although urine NT-proBNP of CHF and sepsis cases were significantly higher compared with both cases, the concentration in the AMI cases were significantly high only when compared with the acute death cases. CONCLUSION: This study is the first to elucidate the diagnostic utility of NT-proBNP measurement in urine obtained postmortem in a series of causes of death. This study suggests the diagnostic efficacy for AMI, CHF, and sepsis-related fatality in cases in which the PMI was within 72h.

Pericardial fluids or Cardiopulmonary Bypass-Is There a Major Culprit for Changes in Coagulation and Inflammation?

BACKGROUND: From the results of a previous study, it remained to be investigated if a perioperative rise of few tested coagulation and inflammation markers is caused by conventional cardiopulmonary bypass (CPB) itself or rather by direct recirculation of pericardial fluids. METHODS: Forty-eight patients operated on with conventional CPB for myocardial revascularization were randomized either for direct recirculation of pericardial suction fluids or for cell saving (CS). RESULTS: Thrombin-antithrombin complexes showed lower values intraoperatively in the CS group (p < 0.0001), and D-dimers tended to remain lower at intensive care unit arrival (p = 0.095). Tests of inflammation markers were less meaningful. CONCLUSION: Direct recirculation of pericardial fluids rather than conventional CPB itself causes major intraoperative changes of some coagulation markers. Pericardial blood loss with direct recirculation should be kept to a minimum to avoid unnecessary activation of coagulation. Inflammation markers need further investigations.

Evaluation of the distribution of nicotine intravenous injection: an adult autopsy case report with a review of literature.

We reported the first comprehensive autopsy case of death due to intravenous injection of nicotine. We examined the distribution of nicotine in the body tissues and fluid and exposed the pathophysiology of nicotine poisoning. A 19-year-old woman was rushed to the hospital in cardiorespiratory arrest and was confirmed dead upon arrival. Liquid nicotine, hydrogen peroxide water, and a syringe were found in the hotel room where she stayed. On autopsy, nicotine concentration was the highest (15,023 µg/mg) in the tissue around the injection mark on the right upper arm. Among the body fluids, the intraperitoneal fluid had the highest, whereas the pericardial fluid had the lowest (0.736 µg/mL) nicotine concentration. Among the organs, the brain had the highest (11.637 µg/mg), whereas the fat tissue had the lowest (1.307 µg/mg) nicotine concentration. The concentration of cotinine, which is the metabolite of nicotine, was the highest in the tissue around the injection mark on the right arm (5.495 µg/mg) and was almost the same among the other body fluids and organs. The respective concentrations of nicotine and cotinine were 1.529 µg/mL and 0.019 µg/mL in the left heart blood and 3.157 µg/mL and 0.002 µg/mL in right heart blood. In this case, the nicotine concentrations in blood reached the lethal level. The distributions of nicotine and cotinine, as indicated by the intravenous injection, were related to the distribution of organs that metabolize nicotine and the distribution of nicotinic acetylcholine receptors.

Evaluation of Agonal Cardiac Function for Sudden Cardiac Death in Forensic Medicine with Postmortem Brain Natriuretic Peptide (BNP) and NT-proBNP: A Meta-analysis.

Sudden cardiac death (SCD) is an unexpected death caused by a sudden loss of cardiac function, which is currently a global public health problem. Evaluation of the agonal cardiac function of the deceased is a quite important task for the diagnosis of SCD in forensic medicine. Brain natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are currently considered as significant biomarkers for the diagnosis of heart failure in both clinical and forensic practices. To investigate the postmortem evaluation roles of postmortem BNP and NT-proBNP levels for SCD, the present study meta-analyzed eight related studies from Embase, Cochrane Library, PubMed, China Biomedical Literature Database, China National Knowledge Infrastructure, and Wanfang Data. Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of the included literature, and the meta-analysis was performed by RevMan 5.3.5 software. Postmortem NT-proBNP in pericardial fluid showed higher levels in the SCD group than that of the non-SCD group with the weighted mean difference = 3665.74, 95% confidence interval: 1812.89-5518.59, and p = 0.0001. However, postmortem levels of BNP in pericardial fluid and NT-proBNP in serum revealed no statistical difference between SCD and non-SCD subjects. The results of present meta-analysis demonstrated that postmortem NT-proBNP in the pericardial fluid could be used as an ancillary indicator for evaluation of agonal cardiac function in forensic medicine.

mRNA expression patterns in human myocardial tissue, pericardial fluid and blood, and its contribution to the diagnosis of cause of death.

Gene expression has become an interesting research area in forensic pathology to investigate the process of death at the molecular level. The aims of this study were to analyze changes in gene expression patterns in relation to the cause of death, and to propose new molecular markers of myocardial ischemia of potential use for the postmortem diagnosis of early ischemic heart damage in cases of sudden cardiac death (SCD). We determined mRNA levels of five proteins related with ischemic myocardial damage and repair - TNNI3, MYL3, TGFB1, MMP9 and VEGFA - in specific sites of the myocardium, blood and pericardial fluid in samples from 30 cadavers with different causes of death (SCD, multiple trauma, mechanical asphyxia, and other natural deaths). TNNI3 expression in blood, and MMP9 expression in pericardial fluid, were significantly higher when the cause of death was mechanical asphyxia, probably because of the more sensitive response of these proteins to acute systemic hypoxia/ischemia. Specifically, among SCD cases, increased MYL3, VEGFA and MMP9 values in the anterior wall of the right ventricle were found when the confirmed cause of death was acute myocardial infarction (AMI). Higher TGFB1 expression was found in the interventricular septum when AMI was not the cause of death, most likely as a reflection of the short duration of ischemia. Molecular biology techniques can provide complementary tools for the forensic diagnosis of early ischemic myocardial damage and AMI, and may make it possible to determine the duration and severity of myocardial ischemia.

Human pericardial proteoglycan 4 (lubricin): Implications for postcardiotomy intrathoracic adhesion formation.

OBJECTIVE: Intrapericardial fibrous adhesions increase the risk of sternal reentry. Proteoglycan 4/lubricin (PRG4) is a mucin-like glycoprotein that lubricates tissue compartments and prevents inflammation. We characterized PRG4 expression in human pericardium and examined its effects in vitro on human cardiac myofibroblast fibrotic activity and in vivo as a measure of its therapeutic potential to prevent adhesions. METHODS: Full-length PRG4 expression was determined using Western blot analysis and amplified luminescent proximity homogeneous assay in human pericardial tissues obtained at cardiotomy. The in vitro effects of PRG4 were investigated on human cardiac myofibroblasts for cell adhesion, collagen gel contraction, and cell-mediated extracellular matrix remodeling. The influence of PRG4 on pericardial homeostasis was determined in a chronic porcine animal model. RESULTS: PRG4 is expressed in human pericardial fluid and colocalized with pericardial mesothelial cells. Recombinant human PRG4 prevented human cardiac myofibroblast attachment and reduced myofibroblast activity assessed using collagen gel contraction assay (64.6% ± 8.1% vs 47.1% ± 6.8%; P = .02). Using a microgel assay, human cardiac myofibroblast mediated collagen fiber remodeling was attenuated by PRG4 (1.17 ± 0.03 vs 0.90 ± 0.05; P = .002). In vivo, removal of pericardial fluid alone induced severe intrapericardial adhesion formation, tissue thickening, and inflammatory fluid collections. Restoration of intrapericardial PRG4 was protective against fibrous adhesions and preserved the pericardial space. CONCLUSIONS: For the first time, we show that PRG4 is expressed in human pericardial fluid and regulates local fibrotic myofibroblast activity. Loss of PRG4-enriched pericardial fluid after cardiotomy might induce adhesion formation. Therapeutic restoration of intrapericardial PRG4 might prevent fibrous/inflammatory adhesions and reduce the risk of sternal reentry.

Alpha-fetoprotein in pericardial, peritoneal, and pleural fluids: A body fluid matrix evaluation.

OBJECTIVES: Alpha-fetoprotein (AFP) measurement in pericardial, peritoneal (ascites), and pleural fluids is sometimes requested by clinicians as supportive evidence in the evaluation of suspected malignancy. As commercially available, Food and Drug Administration (FDA)-cleared AFP assays are not validated for these fluid types, laboratories must complete additional validation studies to comply with regulatory requirements for body fluid testing. The objective of this study was therefore to conduct a matrix evaluation for these body fluid types using the Beckman Access AFP assay on the UniCel DxI 800 immunoassay system. DESIGN AND METHODS: Using an Institutional Review Board (IRB) approved protocol, previously collected pericardial fluid, peritoneal fluid, pleural fluid, and serum specimens were de-identified and frozen at -20 °C prior to matrix evaluation experiments. Spiked recovery, mixed recovery/linearity, and precision studies were conducted. RESULTS: In spiked and mixed recovery studies, the average percent (%) recovery was within predefined acceptable limits (±15%) for all three body fluids. Linearity was observed over the analytical measurement range (AMR) for all three body fluids (slope, intercept, systematic error): pericardial 0.988, -0.1, 6.1%; peritoneal 0.986, 0.0, 4.1%; and pleural 1.016, 0.0, 1.6%. Imprecision was ≤6.0% CV for all three body fluids at both high and low AFP concentrations. CONCLUSIONS: Matrix interference with AFP testing was not observed for pericardial, peritoneal, or pleural fluids on the Beckman UniCel DxI 800 system.

Utility of soluble lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) in the postmortem diagnosis of ischemic heart disease.

PURPOSE: Ischemic heart disease (IHD) is a major cause of death in developed countries. Postmortem IHD diagnosis using biochemical markers is difficult because of the postmortem changes. In the present study, we investigated the utility of soluble lectin-like low-density lipoprotein receptor-1 (sLOX-1) in body fluids obtained from forensic autopsy cases. METHODS: We measured pericardial fluid, urine, and serum sLOX-1 levels; these samples were obtained from medicolegal autopsy cases (n = 149, postmortem interval <72 h), and the utility of these biomarkers postmortem acute IHD diagnosis was evaluated. RESULTS: The pericardial fluid and urine of patients with acute IHD had higher sLOX-1 levels (p < .05) compared to the controls. No significant differences were found between the sLOX-1 level and the degree of coronary atherosclerosis, body mass index, and postmortem interval. CONCLUSION: sLOX-1 levels in pericardial fluid and urine samples obtained postmortem are useful markers of acute IHD.