Machine learning evaluation for identification of M-proteins in human serum.

Serum electrophoresis (SPEP) is a method used to analyze the distribution of the most important proteins in the blood. The major clinical question is the presence of monoclonal fraction(s) of antibodies (M-protein/paraprotein), which is essential for the diagnosis and follow-up of hematological diseases, such as multiple myeloma. Recent studies have shown that machine learning can be used to assess protein electrophoresis by, for example, examining protein glycan patterns to follow up tumor surgery. In this study we compared 26 different decision tree algorithms to identify the presence of M-proteins in human serum by using numerical data from serum protein capillary electrophoresis. For the automated detection and clustering of data, we used an anonymized data set consisting of 67,073 samples. We found five methods with superior ability to detect M-proteins: Extra Trees (ET), Random Forest (RF), Histogram Grading Boosting Regressor (HGBR), Light Gradient Boosting Method (LGBM), and Extreme Gradient Boosting (XGB). Additionally, we implemented a game theoretic approach to disclose which features in the data set that were indicative of the resulting M-protein diagnosis. The results verified the gamma globulin fraction and part of the beta globulin fraction as the most important features of the electrophoresis analysis, thereby further strengthening the reliability of our approach. Finally, we tested the algorithms for classifying the M-protein isotypes, where ET and XGB showed the best performance out of the five algorithms tested. Our results show that serum capillary electrophoresis combined with decision tree algorithms have great potential in the application of rapid and accurate identification of M-proteins. Moreover, these methods would be applicable for a variety of blood analyses, such as hemoglobinopathies, indicating a wide-range diagnostic use. However, for M-protein isotype classification, combining machine learning solutions for numerical data from capillary electrophoresis with gel electrophoresis image data would be most advantageous.

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

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

Metagenomic sequencing of human cardiac tissue reveals Microbial RNA which correlates with Toll-like receptor-associated inflammation in patients with heart disease.

Cardiovascular disease (CVD) is strongly associated with chronic low-grade inflammation, involving activated Toll-like receptors and their downstream cellular machinery. Moreover, CVD and other related inflammatory conditions are associated with infiltration of bacteria and viruses originating from distant body sites. Thus, in this study we aimed to map the presence of microbes in the myocardium of patients with heart disease that we previously found to display upregulated Toll-like receptor signaling. We performed metagenomics analysis of atrial cardiac tissue from patients undergoing coronary artery bypass grafting (CABG) or aortic valve replacement (AVR) and compared with atrial cardiac tissue from organ donors. A total of 119 species of bacteria and seven species of virus were detected in the cardiac tissue. RNA expression of five bacterial species were increased in the patient group of which L. kefiranofaciens correlated positively with cardiac Toll-like receptor-associated inflammation. Interaction network analysis revealed four main gene set clusters involving cell growth and proliferation, Notch signaling, G protein signaling and cell communication in association with L. kefiranofaciens RNA expression. Taken together, intracardial expression of L. kefiranofaciens RNA correlates with pro-inflammatory markers in the diseased cardiac atrium and may have an effect on specific signaling processes important for cell growth, proliferation and cell communication.

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

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

Markedly reduced myocardial expression of γ-protocadherins and long non-coding RNAs in patients with heart disease.

BACKGROUND: Adverse cardiac remodeling and tissue damage following heart disease is strongly associated with chronic low grade inflammation. The mechanisms underlying persisting inflammatory signals are not fully understood, but may involve defective and/or non-responsive transcriptional and post-transcriptional regulatory mechanisms. In the current study, we aimed to identify novel mediators and pathways involved in processes associated with inflammation in the development and maintenance of cardiac disease. METHODS AND RESULTS: We performed RNA sequencing analysis of cardiac tissue from patients undergoing coronary artery bypass grafting (CABG) or aortic valve replacement (AVR) and compared with control tissue from multi-organ donors. Our results confirmed previous findings of a marked upregulated inflammatory state, but more importantly, we found pronounced reduction of non-protein coding genes, particularly long non-coding RNAs (lncRNA), including several lncRNAs known to be associated with inflammation and/or cardiovascular disease. In addition, Gene Set Enrichment Analysis revealed markedly downregulated microRNA pathways, resulting in aberrant expression of other genes, particularly γ-protocadherins. CONCLUSIONS: Our data suggest that aberrant expression of non-coding gene regulators comprise crucial keys in the progression of heart disease, and may be pivotal for chronic low grade inflammation associated with cardiac dysfunction. By unmasking atypical γ-protocadherin expression as a prospective genetic biomarker of myocardial dysfunction, our study provides new insight into the complex molecular framework of heart disease. Creating new approaches to modify non-coding gene regulators, such as those identified in the current study, may define novel strategies to shift γ-protocadherin expression, thereby normalizing part of the molecular architecture associated with heart disease.

Wide QRS-T angles are associated with markers of increased inflammatory activity independently of hypertension and diabetes.

BACKGROUND: Wide QRS-T angles and inflammatory activity are markers of future cardiovascular events including sudden cardiac death (SCD). The association between wide QRS-T angles and inflammatory activation is however not fully understood. METHODS: 1,094 study participants of both sexes, 50-64 years old, were included from a randomly selected population-based cohort as a part of the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot study. Serum samples were analyzed for markers of inflammation, cardiac wall stress/injury, and the metabolic syndrome. Wide QRS-T angles were defined using Frank vectorcardiography. Variables were analyzed through unsupervised principal component analysis (PCA) as well as Orthogonal Projections to Latent Structures (OPLS) modeling. In addition, a subset of study participants was analyzed in a post hoc matched group design. RESULTS: Wide QRS-T angles correlated positively with markers of inflammation, cardiac wall stress/injury, the metabolic syndrome, and male sex in both PCA and OPLS models. In the matched post hoc analysis, participants with wide QRS-T angles had significantly higher counts of white blood cells (WBC) and neutrophils in comparison with matched controls. WBC as well as the number of neutrophils, monocytes, basophils, eosinophils and levels of C-reactive protein, IL-1, IL-4, IL-6, TNF-α, and NT-pro-BNP were also significantly higher in comparison with healthy controls. CONCLUSIONS: Markers of inflammatory activation and cardiac injury/wall stress were significantly higher in the presence of wide QRS-T angles. These results corroborate an association between abnormal electrophysiological function and inflammatory activation and may have implications for the prediction of SCD.

Toll-like receptor-mediated inflammation markers are strongly induced in heart tissue in patients with cardiac disease under both ischemic and non-ischemic conditions.

BACKGROUND: A sustained low grade inflammatory state is a recognized feature of various diseases, including cardiovascular disease. This state of chronic inflammation involves activation of Toll-like receptor (TLR) signaling. However, little is known regarding the genetic profile of TLR components in cardiac tissue from patients with cardiac disease. METHODS: In this study we investigated the genetic profile of 84 TLR markers in a unique set of cardiac tissue from patients that had undergone either coronary artery bypass grafting (CABG) or aortic valve replacement (AVR). In addition, we compared the gene data from the cardiac tissue with the same gene profile in blood as well as circulating cytokines to elucidate possible targets in blood that could be used to estimate the inflammatory state of the heart in cardiac disease. RESULTS: We found a marked upregulation of TLR-induced inflammation in cardiac tissue from both patient groups compared to healthy controls. The inflammation appeared to be primarily mediated through TLR1, 3, 7, 8 and 10, resulting in a marked induction of mediators of the innate immune response. Furthermore, the gene expression data in combination with unbiased multivariate analysis suggested a difference in inflammatory response in ischemic cardiac tissue compared to non-ischemic cardiac tissue. Serum levels of IL-13 were significantly elevated in both CABG and AVR patients compared to controls, whereas other cytokines did not appear to coincide with cardiac TLR-induced inflammation. CONCLUSIONS: We propose that cardiac disease in humans may be mediated by local cardiac TLR signaling under both ischemic and non-ischemic conditions.

Galectin-1 is inversely associated with type 2 diabetes independently of obesity - A SCAPIS pilot study.

OBJECTIVES: Galectin-1 is a recently discovered adipokine that increases with obesity and increased energy intake in adipose tissue. Our aim was to assess whether serum galectin-1 is associated with type 2 diabetes (T2D) and other parameters of the metabolic syndrome independently of body mass index (BMI) in a cohort from the general population. METHODS: In this cross-sectional population-based cohort study from the western part of Sweden, we investigated associations between serum galectin-1, clinical characteristics and inflammatory markers in 989 women and men aged 50-65 years [part of the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot cohort]. RESULTS: We showed in linear models that serum galectin-1 was independently and: (1) inversely associated with T2D (p < 0.05) and glucose (p < 0.05); and (2) positively associated with age (p < 0.01), sex (p < 0.01), BMI (p < 0.01), insulin (p < 0.01) and C-reactive protein (p < 0.01). Furthermore, galectin-1 demonstrated univariate correlations with triglycerides (r = 0.20, p < 0.01), homeostasis model assessment for insulin resistance (r = 0.24, p < 0.01), tumor necrosis factor-α (r = 0.24, p < 0.01), interleukin-6 (IL-6; r = 0.20, p < 0.01) and HbA1c (r = 0.14, p < 0.01). CONCLUSION: In a cross-sectional study of a middle-aged population, we showed that serum galectin-1 is: (1) inversely associated with T2D independently of BMI; and (2) independently associated with other markers of the metabolic syndrome These results warrant prospective and functional studies on the role of galectin-1 in T2D.

Imaging of Intracellular and Extracellular ROS Levels in Atherosclerotic Mouse Aortas Ex Vivo: Effects of Lipid Lowering by Diet or Atorvastatin.

OBJECTIVE: The first objective was to investigate if intracellular and extracellular levels of reactive oxygen species (ROS) within the mouse aorta increase before or after diet-induced lesion formation. The second objective was to investigate if intracellular and extracellular ROS correlates to cell composition in atherosclerotic lesions. The third objective was to investigate if intracellular and extracellular ROS levels within established atherosclerotic lesions can be reduced by lipid lowering by diet or atorvastatin. APPROACH AND RESULTS: To address our objectives, we established a new imaging technique to visualize and quantify intracellular and extracellular ROS levels within intact mouse aortas ex vivo. Using this technique, we found that intracellular, but not extracellular, ROS levels increased prior to lesion formation in mouse aortas. Both intracellular and extracellular ROS levels were increased in advanced lesions. Intracellular ROS correlated with lesion content of macrophages. Extracellular ROS correlated with lesion content of smooth muscle cells. The high levels of ROS in advanced lesions were reduced by 5 days high dose atorvastatin treatment but not by lipid lowering by diet. Atorvastatin treatment did not affect lesion inflammation (aortic arch mRNA levels of CXCL 1, ICAM-1, MCP-1, TNF-α, VCAM, IL-6, and IL-1ß) or cellular composition (smooth muscle cell, macrophage, and T-cell content). CONCLUSIONS: Aortic levels of intracellular ROS increase prior to lesion formation and may be important in initiation of atherosclerosis. Our results suggest that within lesions, macrophages produce mainly intracellular ROS whereas smooth muscle cells produce extracellular ROS. Short term atorvastatin treatment, but not lipid lowering by diet, decreases ROS levels within established advanced lesions; this may help explain the lesion stabilizing and anti-inflammatory effects of long term statin treatment.

The VLDL receptor promotes lipotoxicity and increases mortality in mice following an acute myocardial infarction.

Impaired cardiac function is associated with myocardial triglyceride accumulation, but it is not clear how the lipids accumulate or whether this accumulation is detrimental. Here we show that hypoxia/ischemia-induced accumulation of lipids in HL-1 cardiomyocytes and mouse hearts is dependent on expression of the VLDL receptor (VLDLR). Hypoxia-induced VLDLR expression in HL-1 cells was dependent on HIF-1α through its interaction with a hypoxia-responsive element in the Vldlr promoter, and VLDLR promoted the endocytosis of lipoproteins. Furthermore, VLDLR expression was higher in ischemic compared with nonischemic left ventricles from human hearts and was correlated with the total lipid droplet area in the cardiomyocytes. Importantly, Vldlr-/- mice showed improved survival and decreased infarct area following an induced myocardial infarction. ER stress, which leads to apoptosis, is known to be involved in ischemic heart disease. We found that ischemia-induced ER stress and apoptosis in mouse hearts were reduced in Vldlr-/- mice and in mice treated with antibodies specific for VLDLR. These findings suggest that VLDLR-induced lipid accumulation in the ischemic heart worsens survival by increasing ER stress and apoptosis.

Physical training after percutaneous coronary intervention in patients with stable angina: effects on working capacity, metabolism, and markers of inflammation.

OBJECTIVE: Physical activity is effective in primary and secondary prevention of cardiovascular disease. In this study, we tested the hypothesis that exercise training improves glucose and lipid metabolism, the inflammatory/anti-inflammatory balance, and the outcome of elective percutaneous coronary intervention (PCI) in patients with stable coronary disease. METHODS: Sixty-two patients scheduled to undergo PCI for stable angina were randomized to intensive physical activity (n=33) consisting of home-based exercise on a bicycle ergometer or maintain their usual sedentary life (n=29). The training program started 2 months before PCI and terminated 6 months afterwards. Clinical examination, blood sampling (fasting glucose, glycated hemoglobin, lipid profile, apolipoprotein B, apolipoprotein A1, C-reactive protein, serum amyloid A, interleukin-6, interleukin-8, and interleukin-10), and maximal exercise tests were performed at inclusion, 1 week before PCI, and 3 and 6 months afterwards. RESULTS: Fifty-six patients [28 per group, 45 men, mean age 63 (SD 7.8) years] completed the follow-up. According to self-reports, patients in the training group exercised more often and longer [4.9 (SD 1.1) vs. 0.6 (SD 1.3) days/week, 36 (SD 12) vs. 15 (SD 31) min/session, P<0.0001]. Improvement in maximal exercise capacity was significantly better in the training group [27 (SD 27) vs. 9 (SD 27) W, P=0.02]. Exercise had no significant effects on glucose and lipid metabolism, plasma cytokines, or acute-phase reactants. CONCLUSION: A home-based training program significantly improved maximal exercise capacity but did not affect glucose or lipid metabolism or markers of inflammation.

Myocardial release of FKBP12 and increased production of FKBP12.6 in ischemia and reperfusion experimental models.

BACKGROUND: Coronary artery occlusion and reperfusion may trigger reversible and irreversible ischemic and reperfusion injury. The primary aim of this study was to evaluate protein release into the myocardium in a porcine model during ischemia and reperfusion to search for clarifying models for reperfusion injury and secondarily to investigate release and production of the immunophilins FKBP12/12.6 in this model and in cell cultures. METHODS: In a porcine model local myocardial ischemia was induced during 45min followed by 120min of reperfusion. Microdialysis samples from ischemic and non-ischemic areas were analyzed with surface-enhanced laser desorption ionization (SELDI) mass spectrometry (MS) and Western blotting (WB). Myocardial biopsies from areas at risk and control areas were analyzed with reverse transcription polymerase chain reaction (RT-PCR). Myocardial cell cultures from mice (HL-1 cells) were exposed to hypoxia and then analyzed with WB and RT-PCR. RESULTS: FK binding protein12 (FKBP12), ubiquitin and myoglobin were identified as being released during ischemia and reperfusion in microdialysates. RT-PCR analysis on the biopsies after ischemia revealed a non-significant increase in mRNA expression of FKBP12 and a significant increase in mRNA expression of FKBP12.6. Lysates from HL-1 cells exposed to hypoxia demonstrated increase of FKBP12 and a significant increase in mRNA expression of FKBP12.6. CONCLUSION: In a myocardial ischemic-reperfusion porcine model as well as in hypoxic HL-1 cells, release of FKBP12 and increased production of FKBP12.6 was demonstrated. The findings indicate important mechanisms related to these immunophilins in the reaction to ischemia/hypoxia and reperfusion in the heart.

Inhibitory effect of known antioxidants and of press juice from herring (Clupea harengus) light muscle on the generation of free radicals in human monocytes.

Reactive oxygen species (ROS) can cause oxidative stress, which has been linked to various diseases. It has been suggested that antioxidant-rich foods can reduce such oxidative stress. However, the lack of suitable model systems to screen for in vivo effects of food-derived antioxidants has prevented a clear consensus in this area. In this study, the aim was to use a single-cell model system (human monocyte) to evaluate whether certain pure antioxidants and complex muscle extracts (herring light muscle press juice, PJ) could prevent ROS formation under in vivo like conditions. ROS were excreted from the monocytes upon stimulation with phorbol myristate acetate and were then detected as isoluminol-enhanced chemiluminescence (CL). Adding 2000 units of catalase and 50 units of superoxide dismutase to the monocytes model lowered the CL response by 35 and 86%, respectively. Ascorbate (14.1 mM) lowered the response by 99%, alpha-tocoperhol (188 microM) by 37%, and Trolox (50 microM) by almost 100%. Crude herring PJ gave a dose-dependent reduction in the CL response. At 10, 100, and 1000 times dilution, the PJ reduced the CL signal by 93, 60.5, and 10.6%. PJ fractionated into low molecular weight (LMW) (<1000 Da) and high molecular weight (>3500 Da) fractions decreased the CL response by 52.9 and 71.4%, respectively, at a 100-fold dilution. Evaluation of the PJ samples in the oxygen radical absorbance capacity test indicated that proteins may be the primary radical scavenging compounds of PJ, whereas the ROS-preventing effect obtained from the LMW fraction may also be attributed to other mechanisms. Thus, this study proved that the monocyte assay can be a useful tool for studying whether food-derived antioxidants can limit ROS production under physiologically relevant conditions. It also showed that herring contains numerous aqueous compounds demonstrating antioxidative effects in the monocyte model system.

Secretory phospholipase A2 group V: lesion distribution, activation by arterial proteoglycans, and induction in aorta by a Western diet.

OBJECTIVE: To study the distribution of group V secretory phospholipase A2 (sPLA2) in human and mouse lesions and compare its expression by human vascular cells, its activity toward lipoproteins, and the interaction with arterial proteoglycans (proteoglycans) with those of sPLA2-IIA. In addition, we also investigated the effect of a Western diet and lipopolysaccharide challenge on the aortic expression of these enzymes in mouse models. METHODS AND RESULTS: Immunohistochemistry showed sPLA2-V in human and mouse lesions to be associated with smooth muscle cells and also surrounding foam cells in lipid core areas. mRNA of the enzyme was expressed in human lesions and human vascular cells, supporting the immunohistochemistry data. sPLA2-V but not sPLA2-IIA was active on lipoproteins in human serum. The association with proteoglycans enhanced 2- to 3-fold sPLA2-V activity toward low-density lipoproteins but not that of the group IIA enzyme. Experiments in mouse models showed that treatment with a Western diet induced expression of sPLA2-V but not that of sPLA2-IIA in aorta. On the other hand, lipopolysaccharide-induced acute inflammation augmented the expression of sPLA2-IIA but not that of sPLA2-V. CONCLUSIONS: These results indicate that these phospholipases could have different roles in atherosclerosis.

CRP, interleukin-6, secretory phospholipase A2 group IIA, and intercellular adhesion molecule-1 during the early phase of acute coronary syndromes and long-term follow-up.

OBJECTIVES: The objectives of this study were to examine the time course of the inflammatory response in acute coronary syndromes (ACS) and to assess the markers of inflammation and their relation to disease severity. METHODS: We prospectively studied 134 patients with ACS who survived for at least 30 months. The patients were divided into four groups: acute myocardial infarction (MI) with (n=54) or without (n=46) ST-segment elevation and unstable angina with (n=14) or without (n=20) increased risk. Plasma levels of C-reactive protein (CRP), interleukin-6 (IL-6), secretory phospholipase A2 group IIA (sPLA2-IIA), and intercellular adhesion molecule-1 (ICAM-1) were measured on days 1 and 4 and after 3 and 30 months. RESULTS: The highest levels of CRP and sPLA2-IIA were seen on day 4 but for IL-6 on day 1. These three markers, but not ICAM-1, were significantly related to disease severity, CKMB, and ejection fraction. Patients in Killip class II-IV had higher levels than those in Killip class I. The individual acute-phase responses correlated with marker levels at 3 and 30 months. ICAM-1 correlated with the development of congestive heart failure. CONCLUSIONS: In ACS there seems to be an individual predisposition to inflammatory response. Plasma IL-6 is the first marker to rise, while sPLA2-IIA and CRP peak later. All three markers, especially CRP, may discriminate between MI and non-MI. ICAM-1 seems to reflect other aspects of the inflammatory processes than the other markers. The results emphasize the complexity of the inflammatory response in ACS and stress the need for further studies involving multiple markers.

Regulation and splicing of scavenger receptor class B type I in human macrophages and atherosclerotic plaques.

BACKGROUND: The protective role of high-density lipoprotein (HDL) in the cardiovascular system is related to its role in the reverse transport of cholesterol from the arterial wall to the liver for subsequent excretion via the bile. Scavenger receptor class B type I (SR-BI) binds HDL and mediates selective uptake of cholesterol ester and cellular efflux of cholesterol to HDL. The role of SR-BI in atherosclerosis has been well established in murine models but it remains unclear whether SR-BI plays an equally important role in atherosclerosis in humans. The aim of this study was to investigate the expression of SR-BI and its isoforms in human macrophages and atherosclerotic plaques. METHODS: The effect of hypoxia and minimally modified low-density lipoprotein (mmLDL), two proatherogenic stimuli, on SR-BI expression was studied in human monocyte-derived macrophages from healthy subjects using real-time PCR. In addition, SR-BI expression was determined in macrophages obtained from subjects with atherosclerosis (n = 15) and healthy controls (n = 15). Expression of SR-BI isoforms was characterized in human atherosclerotic plaques and macrophages using RT-PCR and DNA sequencing. RESULTS: SR-BI expression was decreased in macrophages after hypoxia (p < 0.005). In contrast, SR-BI expression was increased by exposure to mmLDL (p < 0.05). There was no difference in SR-BI expression in macrophages from patients with atherosclerosis compared to controls. In both groups, SR-BI expression was increased by exposure to mmLDL (p < 0.05). Transcripts corresponding to SR-BI and SR-BII were detected in macrophages. In addition, a third isoform, referred to as SR-BIII, was discovered. All three isoforms were also expressed in human atherosclerotic plaque. Compared to the other isoforms, the novel SR-BIII isoform was predicted to have a unique intracellular C-terminal domain containing 53 amino acids. CONCLUSION: We conclude that SR-BI is regulated by proatherogenic stimuli in humans. However, we found no differences between subjects with atherosclerosis and healthy controls. This indicates that altered SR-BI expression is not a common cause of atherosclerosis. In addition, we identified SR-BIII as a novel isoform expressed in human macrophages and in human atherosclerotic plaques.

Growth hormone induces myocardial expression of creatine transporter and decreases plasma levels of IL-1beta in rats during early postinfarct cardiac remodeling.

Growth hormone has been proposed as a potential new therapeutic agent for treatment of myocardial infarction (MI) and congestive heart failure (CHF). The purpose of this study was to evaluate the effects of GH on: (a) myocardial expression of creatine transporter (CreaT) during early postinfarct remodeling, (b) myocardial levels of total creatine (TCr) and adenine pool (TAN) and (c) plasma levels of inflammatory cytokines interleukin-1beta (IL-1beta), tumor-necrosis-factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in rat model of postinfarct cardiac remodeling. Myocardial infarction (MI) was induced by ligation of the left coronary artery in male Sprague-Dawley rats (200-250 g). Three different groups were studied: MI rats treated with GH (n=11) (3 mg/kg/day), MI rats treated with saline (n=10), and sham operated rats (n=7). In the myocardium from GH treated rats the level of mRNA CreaT expression was significantly increased (p<0.01). There was no difference in TCr between the rats with MI and sham-operated rats. Treatment with GH had no effect on TCr. GH had no effect on TAN in left ventricle. All three groups had similar levels of IL-6 and TNF-alpha in plasma. In the rats with MI, treatment with GH normalized the levels of IL-1beta (p<0.05). In conclusion GH increased the expression of CreaT and decreased levels of plasma IL-1beta during postinfarct remodeling in rats. These mechanisms may be responsible for the previously reported beneficial effects of GH on myocardial energy metabolism and preservation of cardiac function in the settings of postinfarct remodeling and CHF.

Circulating ICAM-1 (intercellular cell-adhesion molecule 1) is associated with early stages of atherosclerosis development and with inflammatory cytokines in healthy 58-year-old men: the Atherosclerosis and Insulin Resistance (AIR) study.

There is a lack of data on circulating levels of cell-adhesion molecules in relation to subclinical atherosclerosis measured in both the carotid and femoral arteries in humans. The aim of the present study was to investigate the relationship between clinically silent atherosclerosis and cell-adhesion molecules, and to explore the relationship between these molecules, C-reactive protein and the inflammatory cytokines interleukin-6, tumour necrosis factor-alpha (TNF-alpha), soluble TNF-alpha receptor p55 and soluble TNF-alpha receptor p75. The study group (n=391) consisted of clinically healthy 58-year-old men recruited from the general population. The results showed a positive trend between levels of soluble intercellular cell-adhesion molecule 1 (sICAM-1) and plaque occurrence in the carotid and femoral arteries (P=0.008), and also a univariate correlation between sICAM-1 levels and the composite variable of carotid and femoral intima-media thickness (P<0.001). When adjusted for other risk factors, the relationship between sICAM-1 and intima-media thickness no longer reached statistical significance. The level of sICAM-1 was associated with those of the pro-inflammatory cytokine TNF-alpha, its two soluble receptors, and also interleukin-6 and C-reactive protein. Levels of soluble E-selectin and vascular cell-adhesion molecule 1 (VCAM-1) showed weak or no association with subclinical atherosclerosis and inflammatory variables. Thus, in clinically healthy middle-aged men, levels of sICAM-1, but not of soluble VCAM-1 or E-selectin, were associated with both subclinical atherosclerosis and inflammatory variables.