Cancer risk and mortality after solid organ transplantation: A population-based 30-year cohort study in Finland.

Cancer is a significant cause of morbidity and mortality after solid organ transplantation (SOT) and related to lifelong immunosuppression. This retrospective registry study assessed for the first time in Finland population-based cancer risk and cancer mortality after all SOTs (lung and childhood transplantations included) as standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs). Data from transplant registries were linked with the data of Finnish Cancer Registry and Statistics Finland. We followed 6548 consecutive first SOT recipients from 1 January 1987 to 31 December 2016 translating to 66 741 person-years (median follow-up time 8.9 years [interquartile range 4.0-15.1]). In total, 2096 cancers were found in 1483 patients (23% of all patients). Majority of cancers (53%) were nonmelanoma skin cancers (NMSCs). The overall SIR was 3.6 (95% confidence interval [CI]: 3.5-3.8) and the SIR excluding NMSCs was 2.2 (95% CI: 2.0-2.3). SIR for all cancers was highest for heart (5.0) and lowest for liver (2.7) recipients. Most common cancer types after NMSCs were non-Hodgkin lymphoma (NHL), SIR 9.9 (95% CI: 8.5-11.4) and kidney cancer, SIR 7.3 (95% CI: 6.0-8.8). Cancer-related deaths were 17% (n = 408) of all deaths after first month post transplantation. SMR for all cancers was 2.5 (95% CI: 2.2-2.7) and for NHL 13.6 (95% CI: 10.7-16.8). Notably, overall SIR for cancer was lower in later period (2000-2016), 3.0 (95% CI: 2.8-3.2), than in earlier period (1987-1999), 4.3 (95% CI: 4.0-4.5), P < .001. Decrease in cancer incidence was temporally associated with major changes in immunosuppression in the 2000s.

Cholesterol lowering with EVOLocumab to prevent cardiac allograft Vasculopathy in De-novo heart transplant recipients: Design of the randomized controlled EVOLVD trial.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is characterized by diffuse thickening of the arterial intima. Statins reduce the incidence of CAV, but despite the use of statins, CAV remains one of the leading causes of long-term death after heart transplant. Inhibitors of proprotein convertase subtilisin-kexin type 9 (PCSK9) substantially reduce cholesterol levels but have not been tested in heart transplant recipients. METHODS: The Cholesterol lowering with EVOLocumab to prevent cardiac allograft Vasculopathy in De-novo heart transplant recipients (EVOLVD) trial (ClinicalTrials.gov Identifier: NCT03734211) is a randomized, double-blind trial designed to test the effect of the PCSK9 inhibitor evolocumab on coronary intima thickness in heart transplant recipients. Adults who have received a cardiac transplant within the past 4-8 weeks are eligible. Exclusion criteria include an estimated glomerular filtration rate < 20 mL/min/1.73 m2 , renal replacement therapy, or contraindications to coronary angiography with intravascular ultrasound. 130 patients will be randomized (1:1) to 12-month treatment with evolocumab or matching placebo. The primary endpoint is the coronary artery intima thickness as measured by intravascular ultrasound. CONCLUSION: The EVOLVD trial is a randomized clinical trial designed to show whether treatment with the PCSK9 inhibitor evolocumab can ameliorate CAV over the first year after heart transplant.

Percutaneous coronary angioplasty versus coronary artery bypass grafting in treatment of unprotected left main stenosis (NOBLE): a prospective, randomised, open-label, non-inferiority trial.

BACKGROUND: Coronary artery bypass grafting (CABG) is the standard treatment for revascularisation in patients with left main coronary artery disease, but use of percutaneous coronary intervention (PCI) for this indication is increasing. We aimed to compare PCI and CABG for treatment of left main coronary artery disease. METHODS: In this prospective, randomised, open-label, non-inferiority trial, patients with left main coronary artery disease were enrolled in 36 centres in northern Europe and randomised 1:1 to treatment with PCI or CABG. Eligible patients had stable angina pectoris, unstable angina pectoris, or non-ST-elevation myocardial infarction. Exclusion criteria were ST-elevation myocardial infarction within 24 h, being considered too high risk for CABG or PCI, or expected survival of less than 1 year. The primary endpoint was major adverse cardiac or cerebrovascular events (MACCE), a composite of all-cause mortality, non-procedural myocardial infarction, any repeat coronary revascularisation, and stroke. Non-inferiority of PCI to CABG required the lower end of the 95% CI not to exceed a hazard ratio (HR) of 1·35 after up to 5 years of follow-up. The intention-to-treat principle was used in the analysis if not specified otherwise. This trial is registered with ClinicalTrials.gov identifier, number NCT01496651. FINDINGS: Between Dec 9, 2008, and Jan 21, 2015, 1201 patients were randomly assigned, 598 to PCI and 603 to CABG, and 592 in each group entered analysis by intention to treat. Kaplan-Meier 5 year estimates of MACCE were 29% for PCI (121 events) and 19% for CABG (81 events), HR 1·48 (95% CI 1·11-1·96), exceeding the limit for non-inferiority, and CABG was significantly better than PCI (p=0·0066). As-treated estimates were 28% versus 19% (1·55, 1·18-2·04, p=0·0015). Comparing PCI with CABG, 5 year estimates were 12% versus 9% (1·07, 0·67-1·72, p=0·77) for all-cause mortality, 7% versus 2% (2·88, 1·40-5·90, p=0·0040) for non-procedural myocardial infarction, 16% versus 10% (1·50, 1·04-2·17, p=0·032) for any revascularisation, and 5% versus 2% (2·25, 0·93-5·48, p=0·073) for stroke. INTERPRETATION: The findings of this study suggest that CABG might be better than PCI for treatment of left main stem coronary artery disease. FUNDING: Biosensors, Aarhus University Hospital, and participating sites.

Randomized Trial of Cholesterol Lowering With Evolocumab for Cardiac Allograft Vasculopathy in Heart Transplant Recipients.

BACKGROUND: Cardiac allograft vasculopathy is characterized by increased coronary intimal thickness and is a leading cause of death in heart transplant (HTx) recipients despite the routine use of statins. The experience with inhibitors of proprotein convertase subtilisin-kexin type 9 in HTx recipients is limited. Our hypothesis was that lowering cholesterol with the proprotein convertase subtilisin-kexin type 9inhibitor evolocumab would reduce coronary intimal thickness in these patients without compromising safety. OBJECTIVES: This double blind, randomized trial was conducted to test whether evolocumab reduces the burden of cardiac allograft vasculopathy. METHODS: Patients who had received a cardiac allograft at 1 of the Nordic transplant centers within the prior 4 to 8 weeks were randomized to monthly subcutaneous injections of evolocumab 420 mg or matching placebo. The primary endpoint was the baseline-adjusted maximal intimal thickness as measured by intracoronary ultrasound after 12 months' treatment. RESULTS: The trial enrolled 128 patients between June 2019 and May 2022. Matched pairs of coronary ultrasound images were available for 56 patients assigned to evolocumab and 54 patients assigned to placebo. At 12 months, the adjusted mean difference in the maximal intimal thickness between the 2 arms was 0.017 mm (95% CI: -0.006 to 0.040; P = 0.14). The mean reduction in low-density lipoprotein cholesterol with evolocumab compared with placebo was 1.11 mmol/L (95% CI: 0.86-1.37 mmol/L). The use of evolocumab was not associated with an increase in adverse events. CONCLUSIONS: Twelve months of treatment with evolocumab substantially reduced low-density lipoprotein cholesterol but did not reduce maximal coronary intimal thickness in HTx recipients. (Cholesterol Lowering With EVOLocumab to Prevent Cardiac Allograft Vasculopathy in De-novo Heart Transplant Recipients [EVOLVD]; NCT03734211).

Cardiac steatosis and left ventricular function in men with metabolic syndrome.

BACKGROUND: Ectopic accumulation of fat accompanies visceral obesity with detrimental effects. Lipid oversupply to cardiomyocytes leads to cardiac steatosis, and in animal studies lipotoxicity has been associated with impaired left ventricular (LV) function. In humans, studies have yielded inconclusive results. The aim of the study was to evaluate the role of epicardial, pericardial and myocardial fat depots on LV structure and function in male subjects with metabolic syndrome (MetS). METHODS: A study population of 37 men with MetS and 38 men without MetS underwent cardiovascular magnetic resonance and proton magnetic spectroscopy at 1.5 T to assess LV function, epicardial and pericardial fat area and myocardial triglyceride (TG) content. RESULTS: All three fat deposits were greater in the MetS than in the control group (p <0.001). LV diastolic dysfunction was associated with MetS as measured by absolute (471 mL/s vs. 667 mL/s, p = 0.002) and normalized (3.37 s⁻¹ vs. 3.75 s⁻¹, p = 0.02) LV early diastolic peak filling rate and the ratio of early diastole (68% vs. 78%, p = 0.001). The amount of epicardial and pericardial fat correlated inversely with LV diastolic function. However, myocardial TG content was not independently associated with LV diastolic dysfunction. CONCLUSIONS: In MetS, accumulation of epicardial and pericardial fat is linked to the severity of structural and functional alterations of the heart. The role of increased intramyocardial TG in MetS is more complex and merits further study.

Mast cells promote atherosclerosis by inducing both an atherogenic lipid profile and vascular inflammation.

Accumulating in vitro and in vivo studies have proposed a role for mast cells in the pathogenesis of atherosclerosis. Here, we studied the role of mast cells in lipoprotein metabolism, a key element in the atherosclerotic disease. Male mice deficient in low-density lipoprotein receptors and mast cells on a Western diet for 26 weeks had significantly less atherosclerotic changes both in aortic sinus (55%, P = 0.0009) and in aorta (31%, P = 0.049), as compared to mast cell-competent littermates. Mast cell-deficient female mice had significantly less atherosclerotic changes in aortic sinus (43%, P = 0.011). Furthermore, we found a significant positive correlation between the extent of atherosclerosis and the number of adventitial/perivascular mast cells in aortic sinus of mast cell-competent mice (r = 0.615, P = 0.015). Serum cholesterol and triglyceride levels were significantly lower in both male (63%, P = 0.0005 and 57%, P = 0.004) and female (73%, P = 0.00009 and 54%, P = 0.007) mast cell-deficient mice, with a concomitant decrease in atherogenic apoB-containing particles and serum prebeta-high-density lipoprotein and phospholipid transfer protein activity in both male (69% and 24%) and female (74% and 54%) mast cell-deficient mice. Serum soluble intercellular adhesion molecule was decreased in both male (32%, P = 0.004) and female (28%, P = 0.003) mast cell-deficient mice, whereas serum amyloid A was similar between mast cell-deficient and competent mice. In conclusion, mast cells participate in the pathogenesis of atherosclerosis in ldlr(-/-) mice by inducing both an atherogenic lipid profile and vascular inflammation.

Outcome after heart-lung or lung transplantation in patients with Eisenmenger syndrome.

OBJECTIVE: The optimal timing for transplantation is unclear in patients with Eisenmenger syndrome (ES). We investigated post-transplantation survival and transplantation-specific morbidity after heart-lung transplantation (HLTx) or lung transplantation (LTx) in a cohort of Nordic patients with ES to aid decision-making for scheduling transplantation. METHODS: We performed a retrospective, descriptive, population-based study of patients with ES who underwent transplantation from 1985 to 2012. RESULTS: Among 714 patients with ES in the Nordic region, 63 (9%) underwent transplantation. The median age at transplantation was 31.9 (IQR 21.1-42.3) years. Within 30 days after transplantation, seven patients (11%) died. The median survival was 12.0 (95% CI 7.6 to 16.4) years and the overall 1-year, 5-year, 10-year and 15-year survival rates were 84.1%, 69.7%, 55.8% and 40.6%, respectively. For patients alive 1 year post-transplantation, the median conditional survival was 14.8 years (95% CI 8.0 to 21.8), with 5-year, 10-year and 15-year survival rates of 83.3%, 67.2% and 50.0%, respectively. There was no difference in median survival after HLTx (n=57) and LTx (n=6) (14.9 vs 10.6 years, p=0.718). Median cardiac allograft vasculopathy, bronchiolitis obliterans syndrome and dialysis/kidney transplantation-free survival rates were 11.2 (95% CI 7.8 to 14.6), 6.9 (95% CI 2.6 to 11.1) and 11.2 (95% CI 8.8 to 13.7) years, respectively. The leading causes of death after the perioperative period were infection (36.7%), bronchiolitis obliterans syndrome (23.3%) and heart failure (13.3%). CONCLUSIONS: This study shows that satisfactory post-transplantation survival, comparable with contemporary HTx and LTx data, without severe comorbidities such as cardiac allograft vasculopathy, bronchiolitis obliterans syndrome and dialysis, is achievable in patients with ES, with a conditional survival of nearly 15 years.

Acute coronary syndromes and acute heart failure: a diagnostic dilemma and high-risk combination. A statement from the Acute Heart Failure Committee of the Heart Failure Association of the European Society of Cardiology.

Acute coronary syndrome is a precipitant of acute heart failure in a substantial proportion of cases, and the presence of both conditions is associated with a higher risk of short-term mortality compared to acute coronary syndrome alone. The diagnosis of acute coronary syndrome in the setting of acute heart failure can be challenging. Patients may present with atypical or absent chest pain, electrocardiograms can be confounded by pre-existing abnormalities, and cardiac biomarkers are frequently elevated in patients with chronic or acute heart failure, independently of acute coronary syndrome. It is important to distinguish transient or limited myocardial injury from primary myocardial infarction due to vascular events in patients presenting with acute heart failure. This paper outlines various clinical scenarios to help differentiate between these conditions and aims to provide clinicians with tools to aid in the recognition of acute coronary syndrome as a cause of acute heart failure. Interpretation of electrocardiogram and biomarker findings, and imaging techniques that may be helpful in the diagnostic work-up are described. Guidelines recommend an immediate invasive strategy for patients with acute heart failure and acute coronary syndrome, regardless of electrocardiographic or biomarker findings. Pharmacological management of patients with acute coronary syndrome and acute heart failure should follow guidelines for each of these syndromes, with priority given to time-sensitive therapies for both. Studies conducted specifically in patients with the combination of acute coronary syndrome and acute heart failure are needed to better define the management of these patients.

Characterization of different fat depots in NAFLD using inflammation-associated proteome, lipidome and metabolome.

Non-alcoholic fatty liver disease (NAFLD) is recognized as a liver manifestation of metabolic syndrome, accompanied with excessive fat accumulation in the liver and other vital organs. Ectopic fat accumulation was previously associated with negative effects at the systemic and local level in the human body. Thus, we aimed to identify and assess the predictive capability of novel potential metabolic biomarkers for ectopic fat depots in non-diabetic men with NAFLD, using the inflammation-associated proteome, lipidome and metabolome. Myocardial and hepatic triglycerides were measured with magnetic spectroscopy while function of left ventricle, pericardial and epicardial fat, subcutaneous and visceral adipose tissue were measured with magnetic resonance imaging. Measured ectopic fat depots were profiled and predicted using a Random Forest algorithm, and by estimating the Area Under the Receiver Operating Characteristic curves. We have identified distinct metabolic signatures of fat depots in the liver (TAG50:1, glutamate, diSM18:0 and CE20:3), pericardium (N-palmitoyl-sphinganine, HGF, diSM18:0, glutamate, and TNFSF14), epicardium (sphingomyelin, CE20:3, PC38:3 and TNFSF14), and myocardium (CE20:3, LAPTGF-ß1, glutamate and glucose). Our analyses highlighted non-invasive biomarkers that accurately predict ectopic fat depots, and reflect their distinct metabolic signatures in subjects with NAFLD.

Complement regulation in human atherosclerotic coronary lesions. Immunohistochemical evidence that C4b-binding protein negatively regulates the classical complement pathway, and that C5b-9 is formed via the alternative complement pathway.

OBJECTIVE: The complement system is activated in human atherosclerotic lesions and may hence aggravate local inflammation. We studied the presence and localization of C4b-binding protein (C4bp), the major inhibitor of the classical complement pathway, in human atherosclerotic lesions in relation to complement activation products and protein S, which circulates in complex with C4bp. METHODS AND RESULTS: Immunohistochemistry of human coronary arteries showed C4bp to be virtually absent in normal arteries but present in early and advanced atherosclerotic lesions. In the lesions, C4bp is associated with proteoglycans, and affinity chromatography showed that C4bp interacts with human arterial proteoglycans. Areas containing C4bp also contained IgM and C4 suggesting that C4bp is involved in the regulation of the classical complement pathway. However, C5b-9 was virtually absent in these areas but, instead, colocalized with properdin deeper in the intima, suggesting that C5b-9 is formed by the alternative complement pathway. A fraction of C4bp was associated with protein S and apoptotic cells. CONCLUSIONS: The results indicate that C4bp regulates the classical complement pathway in human atherosclerotic lesions. Thus, unlike the alternative pathway, the classical complement pathway does not generate C5b-9, but is likely to be involved in the clean-up of apoptotic cells and cell debris in the arterial intima.

Function and regulation of the complement system in cardiovascular diseases.

The complement system plays a central role in innate immunity and also regulates adaptive immunity. The complement system has been demonstrated to contribute to various diseases, including cardiovascular diseases. Complement is extensively activated in atherosclerotic lesions, in arterial aneurysms, and in the myocardium of ischemic and failing hearts. Accumulating evidence shows that limitation of excessive complement activation under these conditions may hold therapeutic value. On the other hand, defects in the classical complement pathway predispose to vasculitis and atherosclerosis, possibly due to ineffective clearance of apoptotic/necrotic cells and abnormal processing of immune complexes. Here, we describe complement activation and regulation in cardiovascular diseases and discuss the evidence derived mainly from experimental animals suggesting that modulation of complement activation may alter the course of these disorders.

OxLDL-IgG immune complexes induce survival of human monocytes.

OBJECTIVE: Immune complexes containing oxidatively modified low-density lipoprotein (oxLDL) particles are deposited in human atherosclerotic lesions during atherogenesis. Here we studied whether OxLDL-IgG immune complexes (OxLDL-IgG ICs) affect survival of human monocytes. METHODS AND RESULTS: As demonstrated by light microscopy, and analysis of cell proliferation, caspase-3 activity, and DNA fragmentation, OxLDL-IgG ICs promoted survival of cultured human monocytes by decreasing their spontaneous apoptosis. OxLDL-IgG ICs induced a concentration-dependent production of the major monocyte growth factor, monocyte colony-stimulating factor (M-CSF), by the monocytes, but its inhibition was without effect on OxLDL-IgG IC-induced monocyte survival. Rather, OxLDL-IgG ICs induced rapid phosphorylation of Akt, suggesting a direct anti-apoptotic effect mediated by cross-linking of Fcgamma receptors. Experiments with receptor blocking antibodies revealed that the OxLDL-IgG IC-induced monocyte survival was mediated by Fcgamma receptor I. CONCLUSIONS: The results show that OxLDL-IgG ICs promote survival of monocytes by cross-linking Fcgamma receptor I and activating Akt-dependent survival signaling. The results reveal a novel mechanism by which an immune reaction toward oxLDL can play a role in the accumulation of macrophages in human atherosclerotic lesions.

Low-density lipoprotein modified by macrophage-derived lysosomal hydrolases induces expression and secretion of IL-8 via p38 MAPK and NF-kappaB by human monocyte-derived macrophages.

OBJECTIVE: Modified lipoproteins induce inflammatory reactions in the atherosclerotic arterial wall. We have previously found that macrophages in atherosclerotic lesions secrete lysosomal hydrolases that can modify low-density-lipoprotein (LDL) in vitro to generate "hydrolase-modified LDL" (H-LDL). Here, we studied whether H-LDL exerts inflammatory effects on cultured human macrophages. METHODS AND RESULTS: Using cytokine cDNA arrays, we found that H-LDL induced expression of IL-8, but not of the anti-inflammatory cytokines IL-10 and transforming growth factor (TGF)-beta, in human monocyte-derived macrophages. H-LDL induced rapid phosphorylation of the p38 mitogen-activated protein kinase (MAPK), nuclear translocation of 2 transcription factors, nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1), and time-dependent secretion of IL-8 from the macrophages. Inhibition of MAPKs and of transcription factors showed that p38 MAPK and NF-kappaB, but not ERK1/2, JNK, or AP-1, were crucial for the H-LDL-induced IL-8 secretion from the macrophages. CONCLUSIONS: The results show that by activating p38 MAPK and NF-kappaB, macrophage hydrolases modify LDL into biologically active particles capable of triggering the secretion of IL-8 in macrophages. Thus, activated hydrolase-secreting macrophages in atherosclerotic lesions may sustain a proatherogenic extracellular environment by hydrolyzing LDL and triggering it to act in an autocrine or paracrine fashion to induce IL-8 secretion by the plaque macrophages.

Protective effects of simvastatin on coronary artery function in swine with acute infection.

BACKGROUND: The risk for coronary events may rise during acute infection. Perturbation in coronary endothelial function emerges as one important link. We investigated whether simvastatin could protect the coronary arterial function from the adverse effects of acute infection in swine. METHODS: Coronary endothelium-dependent and -independent vasomotor responses were assessed by Doppler velocimetry in 12 Chlamydia pneumoniae-infected and 6 sham-infected swine 2 weeks after intratracheal inoculation. Half of animals from the infection group were pre-treated with simvastatin (80 mg daily), while the remaining animals received placebo. The treatment was started 2 weeks prior to inoculation and continued until the end of the study. ANOVA was used for statistical calculations. Data are mean+/-S.D. RESULTS: All animals inoculated with C. pneumoniae developed IgM antibodies against this organism. As compared to noninfected animals, peak-to-baseline coronary flow velocity (CFV) ratio after bradykinin was significantly decreased in infected animals regardless of statin treatment (p=0.01). Intracoronary 10(-6) M acetylcholine caused slight dilatory responses in both noninfected and infected-treated animals (CFV ratio: 1.6+/-0.2 and 1.4+/-0.2, respectively; p>0.1), while a velocity drop (CFV ratio: 0.7+/-0.1; p<0.01 versus noninfected-infected and treated), indicating constriction, was observed in infected-nontreated animals; 10(-5) M acetylcholine caused vasoconstriction in all animals, with a significantly more prolonged response in the infected-nontreated group (p<0.01). Intracoronary adenosine and SNP induced similar dilatory responses in all groups (p>0.5). There were no differences in markers of systemic inflammation (fibrinogen, amyloid, and CRP) and lipid profile (HDL, LDL and total cholesterol) between the groups (p>0.2). CONCLUSION: Acute infection is associated with impairment of the muscarinic and kinin-related reactivity of coronary circulation. These functional abnormalities are in part prevented by simvastatin through mechanisms unrelated to lipid lowering.

Lipoprotein lipase in the arterial wall: linking LDL to the arterial extracellular matrix and much more.

For low density lipoprotein (LDL) particles to be atherogenic, increasing evidence indicates that their residence time in the arterial intima must be sufficient to allow their modification into forms capable of triggering extracellular and intracellular lipid accumulation. Recent reports have confirmed the longstanding hypothesis that the major determinant(s) of initial LDL retention in the preatherosclerotic arterial intima is the proteoglycans. However, once the initial atherosclerotic lesions have formed, a shift to retention facilitated by macrophage-derived lipoprotein lipase (LPL) appears, leading to the progression of the lesions. Here, we review recent findings on the mechanisms enabling LPL to promote LDL retention and extracellular lipid accumulation in the arterial intima, and we describe the structures in the extracellular matrix that are held to be important in this process. Finally, the potentially harmful consequences of LDL linking by LPL and of other LPL actions in the arterial intima are briefly reviewed.

Mast cells in neovascularized human coronary plaques store and secrete basic fibroblast growth factor, a potent angiogenic mediator.

OBJECTIVE: Intraplaque neovascularization and hemorrhage may facilitate plaque progression. We studied expression of basic fibroblast growth factor (bFGF), a potent angiogenic mediator, by mast cells (MCs) in human coronary plaques with increasing degrees of atherosclerosis. METHODS AND RESULTS: Normal and atherosclerotic coronary segments were collected from 30 autopsied subjects. Immunohistochemical methods were used to detect MCs, bFGF, and microvessels. Both adventitial and intimal MCs showed intracytoplasmic granular staining for bFGF, and bFGF-positive extracellular granules were observed close to the MCs. Increased numbers of bFGF-positive MCs were detected in neovascularized areas of plaques, and there was a positive correlation between numbers of bFGF-positive MCs and microvessels in both the intima and adventitia. In plaques, the highly neovascularized areas contained increased numbers of bFGF-positive MCs compared with the adjacent nonvascularized areas, where only few MCs were present. Importantly, the proportion of intimal MCs expressing bFGF increased with increasing severity of atherosclerosis. CONCLUSIONS: The present work reveals a novel source of bFGF in human coronary arteries, the intimal and adventitial MCs. The association of bFGF-positive MCs with microvessels and with the severity of atherosclerosis suggests that coronary MCs, by releasing bFGF, may play a role in angiogenesis and progression of coronary plaques.

Association between complement factor H and proteoglycans in early human coronary atherosclerotic lesions: implications for local regulation of complement activation.

OBJECTIVE: Complement activation has been suggested to play a role in atherogenesis. To study the regulation of complement activation in human coronary atherosclerotic lesions, we examined the spatial relationships between the major complement inhibitor, factor H, and the complement activation products C3d and C5b-9. METHODS AND RESULTS: In early lesions (American Heart Association types II and III), factor H was immunohistochemically found in the superficial proteoglycan-rich layer in association with numerous macrophages and C3d, whereas C5b-9 was found deeper in the intima, where factor H was virtually absent. In vitro experiments involving surface plasmon resonance and affinity chromatography analyses demonstrated that isolated human arterial proteoglycans bind factor H, and functional complement assays showed that glycosaminoglycans inhibit the complement activation induced by modified low density lipoprotein or by a foreign surface. CONCLUSIONS: The present observations raise the possibility that proteoglycans, because of their ability to bind the major complement inhibitor factor H, may inhibit complement activation in the superficial layer of the arterial intima. In contrast, deeper in the intima, where factor H and proteoglycans are absent, complement may be activated and proceed to C5b-9. Thus, the superficial and the deep layers of the human coronary artery appear to differ in their ability to regulate complement activation.

Lysosomal enzymes are released from cultured human macrophages, hydrolyze LDL in vitro, and are present extracellularly in human atherosclerotic lesions.

OBJECTIVE: Human atherosclerotic lesions have been shown to contain lipid droplets and vesicles resembling those of in vitro enzymatically modified LDL. However, little is known about the hydrolytic enzymes in the arterial intima that induce fusion of LDL particles and so produce lipid droplets or that induce foam cell formation. METHODS AND RESULTS: Human coronary atherosclerotic lesions obtained at surgery and at autopsy were stained for lysosomal acid lipase and cathepsin D. The extracellular areas of macrophage-rich intimal regions of the atherosclerotic lesions stained positively for both cathepsin D and lysosomal acid lipase, whereas normal arteries were negative. When monocyte-derived macrophages were incubated with opsonized zymosan to stimulate the release of lysosomal enzymes from the cells and LDL was incubated with the macrophage-conditioned media, the apolipoprotein B-100, cholesteryl esters, and triacylglycerols of LDL were hydrolyzed. These hydrolytic modifications rendered the LDL particles unstable and induced their fusion. Cultured macrophages and smooth muscle cells took up the hydrolase-modified LDL particles avidly and were transformed into foam cells. CONCLUSIONS: Our in vivo and in vitro results suggest that lysosomal enzymes released from macrophages may induce hydrolytic modification of LDL and foam cell formation in the human arterial intima.

Rupture of the atherosclerotic plaque: does a good animal model exist?

By its very nature, rupture of the atherosclerotic plaque is difficult to study directly in humans. A good animal model would help us not only to understand how rupture occurs but also to design and test treatments to prevent it from happening. However, several difficulties surround existing models of plaque rupture, including the need for radical interventions to produce the rupture, lack of direct evidence of rupture per se, and absence of convincing evidence of platelet- and fibrin-rich thrombus at the rupture site. At the present time, attention should therefore focus on the processes of plaque breakdown and thrombus formation in humans, whereas the use of animal models should probably be reserved for studying the function of particular genes and for investigating isolated features of plaques, such as the relationship between cap thickness and plaque stability.

Ectopic fat depots and left ventricular function in nondiabetic men with nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease has emerged as a novel cardiovascular risk factor. The aim of the study was to assess the effect of different ectopic fat depots on left ventricular (LV) function in subjects with nonalcoholic fatty liver disease. METHODS AND RESULTS: Myocardial and hepatic triglyceride contents were measured with 1.5 T magnetic resonance spectroscopy and LV function, visceral adipose tissue (VAT) and subcutaneous adipose tissue, epicardial and pericardial fat by MRI in 75 nondiabetic men. Subjects were stratified by hepatic triglyceride content into low, moderate, and high liver fat groups. Myocardial triglyceride, epicardial and pericardial fat, VAT, and subcutaneous adipose tissue increased stepwise from low to high liver fat group. Parameters of LV diastolic function showed a stepwise decrease over tertiles of liver fat and VAT, and they were inversely correlated with hepatic triglyceride, VAT, and VAT/subcutaneous adipose tissue ratio. In multivariable analyses, hepatic triglyceride and VAT were independent predictors of LV diastolic function, whereas myocardial triglyceride was not associated with measures of diastolic function. CONCLUSIONS: Myocardial triglyceride, epicardial and pericardial fat increased with increasing amount of liver fat and VAT. Hepatic steatosis and VAT associated with significant changes in LV structure and function. The association of LV diastolic function with hepatic triglyceride and VAT may be because of toxic systemic effects. The effects of myocardial triglyceride on LV structure and function seem to be more complex than previously thought and merit further study.