Relationship of thrombus healing to underlying plaque morphology in sudden coronary death

OBJECTIVES

The aim of this study was to assess differences in thrombus healing between ruptured and eroded plaques, given the natural difference in lesion substrate and that thrombi might exist days to weeks before the presentation of sudden coronary death.

BACKGROUND

Although the ability to distinguish ruptures and erosions remains a major clinical challenge, in-hospital patients dying with acute myocardial infarction establish that erosions account for 25% of all deaths, where women experience a higher incidence compared with men.

METHODS

Coronary lesions with thrombi (ruptures, n = 65; erosions, n = 50) received in consultation from the Medical Examiner's Office from 111 sudden death victims were studied. Thrombus healing was classified as early (<1 day) or late stage characterized in phases of lytic (1 to 3 days), infiltrating (4 to 7 days), or healing (>7 days). Morphometric analysis included vessel dimensions, necrotic core size, and macrophage density.

RESULTS

Late-stage thrombi were identified in 79 of 115 (69%) culprit plaques. Women more frequently had erosion with a greater prevalence of late-stage thrombi (44 of 50, 88%) than ruptures (35 of 65, 54%, p < 0.0001). The internal elastic lamina area and percent stenosis were significantly smaller in erosions compared with ruptures (p < 0.0001 and p = 0.02), where plaque burden was greater (p = 0.008). Although macrophage infiltration in erosions was significantly less than ruptures (p = 0.03), there was no established relationship with thrombus organization. Other parameters of thrombus length and occlusive versus nonocclusive showed no association with healing.

CONCLUSIONS

Approximately two-thirds of coronary thrombi in sudden coronary deaths are organizing, particularly in young individuals-especially women, who perhaps might require a different strategy of treatment.

Right-to-left ventricular diastolic delay in chronic thromboembolic pulmonary hypertension is associated with activation delay and action potential prolongation in right ventricle

BACKGROUND

Delayed left ventricle (LV)-to-right ventricle (RV) peak shortening results in cardiac output reduction in patients with chronic thromboembolic hypertension (CTEPH) and other types of pulmonary arterial hypertension. Why the synchrony between LV and RV is lost is unknown. We hypothesized that RV electrophysiological remodeling, notably, conduction slowing and action potential prolongation, contribute to this loss in synchrony.

METHODS AND RESULTS

We conducted epicardial mapping during pulmonary endarterectomy in 26 patients with CTEPH and compared these findings with clinical, hemodynamic, and echocardiographic variables. We consecutively placed a multielectrode grid on the epicardium of the RV free wall and LV lateral wall. These regions corresponded to RV and LV areas where echocardiographic Doppler sample volumes were placed to measure RV-to-LV diastolic interventricular delay. RV and LV epicardial action potential duration was assessed by measuring activation-recovery interval. Onset of diastolic relaxation of RV free wall with respect to LV lateral wall (diastolic interventricular delay) was delayed by 38+/-31 ms in patients with CTEPH versus -12+/-13 ms in control subjects (P<0.001), because, in patients with CTEPH, RV completed electric activation later than LV (65+/-20 versus 44+/-7 ms, P<0.001) and epicardial action potential duration, as assessed by activation-recovery interval measurement, was longer in RV free wall than in LV lateral wall (253+/-29 versus 240+/-22 ms, P<0.001).

CONCLUSIONS

Additive effects of electrophysiological changes in RV, notably, conduction slowing and action potential prolongation, assessed by epicardial activation-recovery interval, contribute to diastolic interventricular delay in patients with CTEPH.

Histopathological features of aspirated thrombi after primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction

Background

Plaque disruption with superimposed thrombus is the predominant mechanism responsible for the onset of acute coronary syndromes. Studies have shown that plaque disruption and thrombotic occlusion are frequently separated in time. We established the histopathological characteristics of material aspirated during primary percutaneous coronary intervention (PCI) in a large consecutive ST-elevation myocardial infarction (STEMI) population.

Methodology/Principal Findings

Thrombus aspiration during primary PCI was performed in 1,362 STEMI patients. Thrombus age was classified as fresh (<1 day), lytic (1–5 days), or organized (>5 day). Further, the presence of plaque was documented. The histopathological findings were related to the clinical, angiographic, and procedural characteristics. Material could be aspirated in 1,009 patients (74%). Components of plaque were found in 395 of these patients (39%). Fresh thrombus was found in 577 of 959 patients (60%) compared to 382 patients (40%) with lytic or organized thrombi. Distal embolization was present in 21% of patients with lytic thrombus compared to 12% and 15% of patients with fresh or organized thrombus.

Conclusions/Significance

Material could be obtained in 74% of STEMI patients treated with thrombus aspiration during primary PCI. In 40% of patients thrombus age is older than 24 h, indicating that plaque disruption and thrombus formation occur significantly earlier than the onset of symptoms in many patients.

Presence of older thrombus is an independent predictor of long-term mortality in patients with ST-elevation myocardial infarction treated with thrombus aspiration during primary percutaneous coronary intervention

BACKGROUND

Routine thrombus aspiration is frequently used during primary percutaneous coronary intervention in patients with ST-elevation myocardial infarction to prevent distal embolization. Recently, evidence of clinical benefit was published. In 50% of the ST-elevation myocardial infarction patients with an onset of symptoms <12 hours before, thrombi were shown to be >1 day old. This observation illustrates that plaque rupture and coronary occlusion are significantly separated in time. In the present study, we correlate the presence of fresh versus older thrombus with long-term mortality.

METHODS AND RESULTS

Thrombus aspiration was performed in 1315 patients treated with primary percutaneous coronary intervention with 3 devices (Rescue, Export, and Proxis). Aspirated material was fixed in formalin and processed for histopathology. If possible, thrombus age was classified as either fresh only (<1 day) or older (>1 day). We identified fresh thrombus in 552 patients and older thrombus in 372 patients. The cumulative Kaplan-Meier estimate of all-cause mortality at 4 years was significantly higher in patients with older thrombus (16.0%) compared with patients with fresh thrombus (7.4%), with a hazard ratio of 1.82 (95% confidence interval, 1.17 to 2.85; P=0.008). Multivariate analysis identified the presence of older thrombus, in addition to other established predictors, as an independent predictor (hazard ratio, 1.83; 95% confidence interval, 1.14 to 2.93; P=0.01) of long-term mortality.

CONCLUSIONS

Our study demonstrates that the presence of older thrombus, in addition to other established predictors, is an independent predictor of long-term mortality in patients with ST-elevation myocardial infarction treated with thrombus aspiration during primary percutaneous coronary intervention.

Nodoventricular Accessory Pathways in PRKAG2 -Dependent Familial Preexcitation Syndrome Reveal a Disorder in Cardiac Development

Background— Familial preexcitation syndrome is linked to mutations in PRKAG2 . Previous studies on the R302Q mutation have provided evidence for a remarkably high proportion of otherwise rare accessory pathways with atrioventricular (AV) node-like conduction properties (Mahaim fibers). Yet, histopathologic proof is still lacking. We aimed to provide such proof.

Methods and Results— We retrospectively studied the medical records of 17 members of a 5-generation family. Five subjects died prematurely. The R302Q mutation was found in 8 living subjects and 2 deceased subjects (obligate carriers). Cardiac hypertrophy was found in 7 mutation carriers. ECGs compatible with preexcitation were found in 13 subjects and AV block at varying degrees in 5 subjects. All mutation carriers had electrocardiographic evidence of preexcitation, AV block, or both. Three individuals had high-grade AV block with preexcited conducted beats. Electrophysiological studies in 3 individuals revealed bypasses with AV node–like properties. Histopathologic studies of 1 suddenly deceased mutation carrier revealed concentric hypertrophy of the left ventricle with extensive myocardial disarray associated with slight interstitial fibrosis but no lysosomal-bound glycogen. Moreover, there were 3 small nodoventricular tracts (Mahaim fibers) passing through the central fibrous body and connecting the AV node with the working myocardium of the interventricular septum.

Conclusions— Preexcitation associated with the R302Q mutation in PRKAG2 is associated with Mahaim fibers. These findings support the novel insight that PRKAG2 may be involved in the development of the cardiac conduction system.

A pyruvate-buffered dialysis fluid induces less peritoneal angiogenesis and fibrosis than a conventional solution

BACKGROUND

Conventional lactate-buffered peritoneal dialysis (PD) fluids containing glucose and glucose degradation products are believed to contribute to the development of fibrosis and angiogenesis in the dialyzed peritoneum. To reduce potential negative effects of lactate, pyruvate was substituted as a buffer and its effects on peritoneal pathological alterations were studied in a chronic peritoneal exposure model in the rat.

METHODS

20 Wistar rats were infused intraperitoneally with pyruvate-buffered (n = 9) or lactate-buffered PD fluid. After 20 weeks of daily infusion, peritoneal function was assessed. In omental peritoneal tissue, the number of blood vessels was analyzed following alpha-smooth muscle actin staining. The degree of fibrosis was quantitated in Picro Sirius Red-stained sections and by assessment of the hydroxyproline content. Plasma lactate/pyruvate and betahydroxybutyrate/acetoacetate (BBA/AA) ratios were determined. Plasma and dialysate vascular endothelial growth factor (VEGF) levels were quantitated by ELISA.

RESULTS

The mass transfer area coefficient of creatinine was higher and the dialysate-to-plasma ratio of sodium was lower in pyruvate-treated animals compared to the lactate-treated group (0.11 vs 0.05 mL/min, p < 0.05, and 78% vs 89%, p < 0.05). The BBA/AA ratio tended to be lower in the pyruvate animals (p = 0.07). The number of blood vessels was lower in pyruvate-treated animals (16 vs 37 per field, p < 0.001). Total surface area, luminal area, and wall/total area of the vessels were larger in the pyruvate group. The degree of fibrosis was lower in intersegmental and perivascular areas of pyruvate-exposed animals. Effluent VEGF was higher in the pyruvate group.

CONCLUSIONS

Replacement of lactate by pyruvate resulted in changes in peritoneal solute transport, accompanied by a reduction in both peritoneal membrane angiogenesis and fibrosis, suggesting potentially novel mechanisms to reduce glucose-driven alterations to the peritoneal membrane in PD patients.

Selective expansion of influenza A virus-specific T cells in symptomatic human carotid artery atherosclerotic plaques

BACKGROUND AND PURPOSE

Evidence is accumulating that infection with influenza A virus contributes to atherothrombotic disease. Vaccination against influenza decreases the risk of atherosclerotic syndromes, indicating that inflammatory mechanisms may be involved. We tested the hypothesis that influenza A virus-specific T cells contribute to atherosclerotic plaque inflammation, which mediates the onset of plaque rupture.

METHODS

T-cell cultures were generated from atherosclerotic segments and peripheral blood of 30 patients with symptomatic carotid artery disease. The response of plaque and peripheral blood T cells to influenza A virus was analyzed and expressed as a stimulation index (SI). Selective outgrowth of intraplaque influenza A-specific T cells was calculated by the ratio of plaque T cell SI and peripheral blood T cell SI for each patient. Accordingly, the patients were categorized as high- (SI ratio >or=5), intermediate- (5 <SI ratio <or=2), and non- (SI ratio <2) responders. The presence of influenza A virus in the vessel fragments was evaluated by reverse transcription-polymerase chain reaction.

RESULTS

High proliferative responses of plaque-derived T cells to influenza A virus were frequently observed. Among the 30 patients, 5 were categorized as high responders, 10 were intermediate responders, and 15 were nonresponders. Live influenza A virus could not be detected in the atherosclerotic plaques by polymerase chain reaction.

CONCLUSIONS

Selective outgrowth of influenza A virus-specific T cells occurs within the microenvironment of human atherosclerotic plaques. Influenza virus-derived antigens or alternatively, mimicry antigens, appear to be potential candidates for triggering or sustaining plaque inflammation, which eventually leads to symptomatic plaque complications.

Low numbers of FOXP3 positive regulatory T cells are present in all developmental stages of human atherosclerotic lesions

Background

T cell mediated inflammation contributes to atherogenesis and the onset of acute cardiovascular disease. Effector T cell functions are under a tight control of a specialized T cell subset, regulatory T cells (Treg). At present, nothing is known about the in situ presence of Treg in human atherosclerotic tissue. In the present study we investigated the frequency of naturally occurring Treg cells in all developmental stages of human atherosclerotic lesions including complicated thrombosed plaques.

Methodology

Normal arteries, early lesions (American Heart Association classification types I, II, and III), fibrosclerotic plaques (types Vb and Vc) and ‘high risk’ plaques (types IV, Va and VI) were obtained at surgery and autopsy. Serial sections were immunostained for markers specific for regulatory T cells (FOXP3 and GITR) and the frequency of these cells was expressed as a percentage of the total numbers of CD3⁺ T cells. Results were compared with Treg counts in biopsies of normal and inflammatory skin lesions (psoriasis, spongiotic dermatitis and lichen planus).

Principle findings

In normal vessel fragments T cells were virtually absent. Treg were present in the intima during all stages of plaque development (0.5–5%). Also in the adventitia of atherosclerotic vessels Treg were encountered, in similar low amounts. High risk lesions contained significantly increased numbers of Treg compared to early lesions (mean: 3.9 and 1.2%, respectively). The frequency of FOXP3⁺ cells in high risk lesions was also higher compared to stable lesions (1.7%), but this difference was not significant. The mean numbers of intimal FOXP3 positive cells in atherosclerotic lesions (2.4%) was much lower than those in normal (24.3%) or inflammatory skin lesions (28%).

Conclusion

Low frequencies of Treg in all developmental stages of human plaque formation could explain the smoldering chronic inflammatory process that takes place throughout the longstanding course of atherosclerosis.

Immunohistochemical Analysis of Regulatory T Cell Markers FOXP3 and GITR on CD4+CD25+ T Cells in Normal Skin and Inflammatory Dermatoses

Regulatory T cells (Treg) are a subset of T lymphocytes that play a central role in immunologic tolerance and in the termination of immune responses. The identification of these cells in normal and inflammatory conditions may contribute to a better understanding of underlying pathology. We investigated the expression of FOXP3 and GITR in normal skin and in a panel of different inflammatory dermatoses. Immunohistochemical double stainings in skin tissue sections revealed that FOXP3 and GITR were almost exclusively present on T cells that express both CD4 and CD25. Further, immunohistochemical double staining, as well as fluorescence-activated cell sorter analysis, on peripheral blood T cells showed that most FOXP3+ cells expressed GITR and vice versa, whereas a minority were single-positive for these markers. The mean frequency of FOXP3+ T cells in spongiotic dermatitis, psoriasis, and lichen planus was in the same range (25-29%), but the frequency of these cells in leishmaniasis appeared to be lower (∼15%), although this was not statistically significant. The mean frequency of GITR+ T cells was fairly similar in all conditions studied (14-20%). Normal human skin also contained FOXP3+ and GITR+ cells in the same frequency range as in diseased skin, but the absolute numbers were, of course, much lower. In conclusion, frequencies of FOXP3+ and GITR+ T cells were similar in all inflammatory skin diseases studied and normal skin, despite the well-known differences among the inflammatory conditions under investigation.

Etiology and incidence of chronic ulcers in Blantyre, Malawi

BACKGROUND

Little information is available on the incidence and etiology of chronic ulcers in the tropics. Therefore, the incidence and etiology of chronic skin ulcers were assessed in out-patients at the Department of Dermatology and in in-patients at the Departments of Dermatology, Surgery, Medicine, and Pediatrics, Queen Elizabeth Central Hospital (QECH), Blantyre, Malawi.

METHOD

In a 10-week study period, 44 patients (31 males, 70%) with chronic skin ulcers were diagnosed from 6292 patients seen by the departments involved.

RESULTS

The mean age of patients with ulcers was 38 years (range, 9 months to 82 years). The most frequent cause of ulcers was bacterial infection (n=22), followed by malignancy (n=11) and trauma (n=7).

CONCLUSION

In contrast with developed countries, venous and diabetic ulcers were uncommon. In addition to bacterial infections, a surprisingly large number of malignancies were found in this study. We speculate that human immunodeficiency virus (HIV) infection, which is seen with a high prevalence at QECH, is a contributing factor. Because of the large number of malignancies, we recommend early histopathologic investigation of chronic ulcers in this part of Africa.

Statin Treatment Is Not Associated With Consistent Alterations in Inflammatory Status of Carotid Atherosclerotic Plaques

BACKGROUND AND PURPOSE

Anti-inflammatory qualities are held partially responsible for the reduction of cardiovascular events after statin treatment. We examined the phenotype of carotid atherosclerotic plaques harvested during carotid endarterectomy in relation to the previous use of different statins prescribed in clinical practice.

METHODS

Three hundred and seventy-eight patients were included. Atherosclerotic plaques were harvested, immunohistochemically stained and semiquantitively examined for the presence of macrophages (CD68), smooth muscle cells, collagen and fat. Adjacent atherosclerotic plaques were used to study protease activity and interleukin levels. Patients' demographics were recorded and blood samples were stored.

RESULTS

Serum cholesterol, low-density lipoprotein, apolipoprotein B, and C-reactive protein levels were lower in patients treated with statins compared with patients without statin treatment. Atheromatous plaques were less prevalent in patients receiving statins compared with patients without statin therapy (29% versus 42%, P=0.04). An increase of CD68 positive cells was observed in patients receiving statins compared with nonstatin treatment (P=0.05). This effect was specifically related to atorvastatin treatment. In patients treated with atorvastatin, the increased amount of CD68 positive cells were not associated with increased protease activity. In contrast, a dose-dependent decrease in protease activity was shown in the atorvastatin group. Interleukin 6 expression was lower in plaques obtained from patients treated with statins (P=0.04).

CONCLUSIONS

Statin use may exert pleiotropic effects on plaque phenotype. However, not the presence of macrophages but activation with subsequent protease and cytokine release may be attenuated by statin use.

Ultrastructural pathology of aortic dissections in patients with Marfan syndrome:

Despite the discovery in 1990 that mutations in the fibrillin-1 gene cause the Marfan syndrome, the pathogenesis of the life-threatening dissections associated with this disease is far from elucidated. Both the massive number of known fibrillin-1 mutations that result in a heterogeneous patient population and the strongly heterogeneous histology of patients' aortae presumably contribute to this lack of knowledge. We performed a detailed ultrastructural immunoelectron microscopic and histochemical analysis of the dissected media of ascending aortae of 10 patients with Marfan syndrome and compared them with those of 6 patients without Marfan syndrome and 77 individuals without known aortic disease. Relatively similar abnormalities were found in both patient groups, although they were more numerous and more diffusely spread in the patients with Marfan syndrome than in the patients without Marfan syndrome. The most conspicuous ultrastructural defects were the formation of abrupt transverse tears in thick and compact elastic lamellae and the local breaking up of smooth muscle cell-elastic lamella connections (that largely consist of microfibrils and elastic extensions, protruding from the elastic lamellae). This breaking up was characterized by a strongly reduced number of microfibrils and a severe shortening of the elastic extensions. Finally, the elastic extensions detached from the lamellae to ultimately degenerate and disappear. These changes were found mainly in the oldest group of patients with Marfan syndrome, indicating that they represented a loss of previously normally developed structures. We also compared our findings with those from a recently developed murine Marfan model (Pereira L, Lee SY, Gayraud B, Andrilopoulos K, Shapiro SD, Bunton T, Biery NJ, Dietz HC, Sakai LY, Ramirez F. Pathogenetic sequence for aneurysm revealed in mice underexpressing fibrillin-1. Proc Natl Acad Sci. U. S. A. 1999: 96: 3819-3823). Next to similarities, several striking differences existed, demonstrating that this model is not fully representative of the human Marfan syndrome.

Microvascular proliferation in congenital vascular malformations of skin and soft tissue

BACKGROUND

Congenital vascular malformations (VMs) are mass-forming lesions that usually progress slowly, but may become symptomatic because of episodes of sudden growth and pain, particularly those with a substantial component of arteriovenous shunting.

AIM

To systematically investigate the features of microvascular proliferation in a large series of surgically treated VMs.

METHODS

107 resection specimens of clinically and histologically well-documented VMs were screened for the presence and extent of microvascular proliferation, based on morphological parameters, microvessel density (MVD), mast cell density (MCD) and proliferative activity (Ki-67 labelling index) of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). The extent of microvascular proliferation was correlated with the histological type of VM and clinical characteristics of patients.

RESULTS

Microvascular proliferation was observed in 32 (30%) of all VMs, of which 30 cases seemed to be arteriovenous malformations. MVD in areas of microvascular proliferation was 282 (186)/mm(2) vs 13 (9)/mm(2) in areas with mature vessels. Both ECs and VSMCs in these areas showed high Ki-67 labelling indexes (mean (SD) 15 (18) and 17 (24)/mm(2), respectively). In all lesions, a positive correlation was found between MCD and MVD. Age, sex and location of VM had no predictive value for the occurrence of microvascular proliferation. However, if present, the involved tissue areas were larger and the proliferative activity of EC was higher in male patients than in female patients.

CONCLUSIONS

Recognition of microvascular proliferation as a not uncommon feature, congenital arteriovenous malformations provide new insight into the growth behaviour and vascular composition of these lesions.

Right ventricular fibrosis and conduction delay in a patient with clinical signs of Brugada syndrome: a combined electrophysiological, genetic, histopathologic, and computational study

BACKGROUND

The mechanism of ECG changes and arrhythmogenesis in Brugada syndrome (BS) patients is unknown.

METHODS AND RESULTS

A BS patient without clinically detected cardiac structural abnormalities underwent cardiac transplantation for intolerable numbers of implantable cardioverter/defibrillator discharges. The patient's explanted heart was studied electrophysiologically and histopathologically. Whole-cell currents were measured in HEK293 cells expressing wild-type or mutated sodium channels from the patient. The right ventricular outflow tract (RVOT) endocardium showed activation slowing and was the origin of ventricular fibrillation without a transmural repolarization gradient. Conduction restitution was abnormal in the RVOT but normal in the left ventricle. Right ventricular hypertrophy and fibrosis with epicardial fatty infiltration were present. HEK293 cells expressing a G1935S mutation in the gene encoding the cardiac sodium channel exhibited enhanced slow inactivation compared with wild-type channels. Computer simulations demonstrated that conduction slowing in the RVOT might have been the cause of the ECG changes.

CONCLUSIONS

In this patient with BS, conduction slowing based on interstitial fibrosis, but not transmural repolarization differences, caused the ECG signs and was the origin of ventricular fibrillation.

Epstein Barr virus specific T-cells generated from unstable human atherosclerotic lesions: Implications for plaque inflammation

OBJECTIVE

T-cell activation is an essential feature of atherosclerotic plaque inflammation, which eventually may lead to plaque rupture. In this study, we investigated if EBV, a common herpes virus, is capable of stimulating atherosclerotic plaque derived T-cells and thus could contribute to atherosclerotic plaque inflammation.

METHODS

Plaque derived T-cell cultures were established from symptomatic carotid atherosclerotic plaques of 19 patients. B-cells from the same patients were transformed with EBV to form lymphoblastoid cell lines (B-LCL) that served as antigen presenting cells. The proliferation of T-cells in the presence of autologous B-LCL was analyzed using 3H-thymidine incorporation. The presence of EBV in atherosclerotic material was analyzed by PCR.

RESULTS

Of the 19 cell obtained T-cell cultures, 11 responded to EBV (58%, mean stimulation index: 10.1+/-3.1). PCR analysis showed that EBV DNA was present in 15 of the tissue samples (79%). All the specimens that contained EBV responding T-cells also contained EBV. EBV specific T-cells secreted granzymes, as indication of functional cytotoxic potential.

CONCLUSIONS

EBV-specific cytotoxic T-cells and EBV DNA can be frequently observed in human atherosclerotic plaques. This suggests that a T-cell response against EBV could contribute to plaque inflammation, and thus to the onset of acute clinical symptoms.

Homozygous and compound heterozygous mutations in ZMPSTE24 cause the laminopathy restrictive dermopathy

Restrictive dermopathy (RD) is a lethal human genetic disorder characterized by very tight, thin, easily eroded skin, rocker bottom feet, and joint contractures. This disease was recently reported to be associated with a single heterozygous mutation in ZMPSTE24 and hypothesized to be a digenic disorder (Navarro et al, Lamin A and ZMPSTE24 (FACE-1) defects cause nuclear disorganization and identify restrictive dermopathy as a lethal neonatal laminopathy. Hum Mol Genet 13:2493-2503, 2004). ZMPSTE24 encodes an enzyme necessary for the correct processing and maturation of lamin A, an intermediate filament component of the nuclear envelope. Here we present four unrelated patients with homozygous mutations in ZMPSTE24 and a fifth patient with compound heterozygous mutations in ZMPSTE24. Two of the three different mutations we found are novel, and all are single base insertions that result in messenger RNA frameshifts. As a consequence of the presumed lack of ZMPSTE24 activity, prelamin A, the unprocessed toxic form of lamin A, was detected in the nuclei of both cultured cells and tissue from RD patients, but not in control nuclei. Abnormally aggregated lamin A/C was also observed. These results indicate that RD is an autosomal recessive laminopathy caused by inactivating ZMPSTE24 mutations that result in defective processing and nuclear accumulation of prelamin A.

Tissue Factor Expression in the Morphologic Spectrum of Vulnerable Atherosclerotic Plaques

Inflammation and thrombosis are key events in the long-lasting sequence of atherosclerotic plaque initiation, plaque growth, and eventual onset of complications leading to clinically manifest disease. Recent cellular and molecular studies have indicated that inside the plaque tissue complex, proinflammatory and prothrombotic mechanisms are intimately associated, and tissue factor (TF) is one of the main proteins that may link both processes. It is therefore not surprising that TF expression appeared to be a prominent feature in various types of vulnerable atherosclerotic plaques (i.e., lesions that specifically predispose to the onset of symptomatic atherosclerotic disease).

Sudden unexplained death: heritability and diagnostic yield of cardiological and genetic examination in surviving relatives

BACKGROUND

Sudden death mostly follows from cardiac disorders that elicit lethal ventricular arrhythmias. In young individuals, it often remains unexplained because history and/or postmortem analysis are absent or provide no clue. Because such sudden unexplained deaths (SUDs) may have heritable causes, cardiological and genetic assessment of surviving relatives of SUD victims may reveal the underlying disease and unmask presymptomatic carriers. We aimed to establish the diagnostic yield of such assessments.

METHODS AND RESULTS

We investigated 43 consecutive families with > or =1 SUD victim who died at < or =40 years of age. All studied relatives underwent resting/exercise ECG and Doppler echocardiography. Molecular genetic analysis was conducted to confirm the diagnosis. We identified an inherited disease and likely cause of death in 17 of 43 families (40%). Twelve families had primary electrical disease: catecholaminergic polymorphic ventricular tachycardia (5 families), long-QT syndrome (4 families), Brugada syndrome (2 families), and long-QT/Brugada syndrome (1 family). Furthermore, we found arrhythmogenic right ventricular cardiomyopathy (3 families), hypertrophic cardiomyopathy (1 family), and familial hypercholesterolemia (1 family). Molecular genetic analysis provided confirmation in 10 families. Finding the diagnosis was more likely when more relatives were examined and in families with > or =2 SUD victims < or =40 years of age. The resting/exercise ECG had a high diagnostic yield. These efforts unmasked 151 presymptomatic disease carriers (8.9 per family).

CONCLUSIONS

Examination of relatives of young SUD victims has a high diagnostic yield, with identification of the disease in 40% of families and 8.9 presymptomatic carriers per family. Simple procedures (examining many relatives) and routine tests (resting/exercise ECG) constitute excellent diagnostic strategies. Molecular genetics provide strong supportive information.

Eosinophilic infiltration in restenotic tissue following coronary stent implantation

OBJECTIVES

The aim of our study was to compare the histopathological features of restenotic tissue after balloon angioplasty and after stent placement. We emphasized on specific types of inflammatory cells to evaluate the type of tissue immune response in both situations.

METHODS

A total of 32 patients underwent elective directional coronary atherectomy; 16 patients had restenosis after balloon angioplasty, 16 patients had in-stent restenosis (ISR). Atherectomy specimens were stained with antibodies against T cells, eosinophils, smooth muscle cell actin, macrophages and with antibodies against T cell activation markers. Quantitative morphometric analysis was performed using image analysis software.

RESULTS

In-stent restenotic tissue contained more smooth muscle cells (P < 0.001), anti-CD3 positive T cells (P < 0.001) and eosinophils (P = 0.012). Anti-CD40L positive activated T cells were more numerous in ISR lesions (P = 0.003) and were frequently clustered around stent imprints in the tissue. Five ISR specimens contained grossly visible stent fragments amidst the restenotic tissue. In all cases of balloon restenosis, T cells and eosinophils (if present) were concentrated around lipid rich tissue.

CONCLUSIONS

Our study indicates involvement of inflammatory responses in both types of restenosis, with significantly more eosinophils encountered in case of in-stent restenosis. In contrast with clustering of inflammatory cells around stent struts after stent placement, the inflammatory cells in balloon restenosis were located in association with lipid rich tissue, suggesting different inflammatory triggers in balloon restenosis and in-stent restenosis.

Disruption of Abcc6 in the mouse: novel insight in the pathogenesis of pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a heritable disorder of connective tissue, affecting mainly skin, eye and the cardiovascular system. PXE is characterized by dystrophic mineralization of elastic fibres. The condition is caused by loss of function mutations in ABCC6. We generated Abcc6 deficient mice (Abcc6-/-) by conventional gene targeting. As shown by light and electron microscopy Abcc6-/- mice spontaneously developed calcification of elastic fibres in blood vessel walls and in Bruch's membrane in the eye. No clear abnormalities were seen in the dermal extracellular matrix. Calcification of blood vessels was most prominent in small arteries in the cortex of the kidney, but in old mice, it occurred also in other organs and in the aorta and vena cava. Newly developed monoclonal antibodies against mouse Abcc6 localized the protein to the basolateral membranes of hepatocytes and the basal membrane in renal proximal tubules, but failed to show the protein at the pathogenic sites. Abcc6-/- mice developed a 25% reduction in plasma HDL cholesterol and an increase in plasma creatinine levels, which may be due to impaired kidney function. No changes in serum mineral balance were found. We conclude that the phenotype of the Abcc6-/- mouse shares calcification of elastic fibres with human PXE pathology, which makes this model a useful tool to further investigate the aetiology of PXE. Our data support the hypothesis that PXE is in fact a systemic disease.

Plaque instability frequently occurs days or weeks before occlusive coronary thrombosis: a pathological thrombectomy study in primary percutaneous coronary intervention

BACKGROUND

Acute ST-elevation myocardial infarction (STEMI) is caused by sudden occlusive coronary thrombosis, after plaque disruption; however, a considerable time interval between plaque disturbance and the onset of symptoms has been suggested. We therefore studied the age of intracoronary thrombi, aspirated during angioplasty in patients with acute STEMI.

METHODS AND RESULTS

Percutaneous intracoronary thrombectomy during angioplasty was performed in 211 consecutive STEMI patients within 6 hours after onset of anginal symptoms. The aspirated material was histologically screened on thrombus and plaque components, and thrombus age was classified as fresh (<1 day), lytic thrombus (1 to 5 days), and organized thrombus (>5 days). In all patients, intracoronary-derived material was retrieved in the filter of the collection bottle. Thrombus was identified in 199 (95%) of 211 patients. In 12 patients (5%), only plaque components were identified, and in 85 patients (41%), both thrombus and plaque material were aspirated. In 18 (9%) of 199 patients, the thrombus was organized, and in 70 patients (35%), the thrombus showed lytic changes, whereas in 98 (49%), a completely fresh thrombus was found. In 14 (7%) of 199 patients, the thrombus showed combined features of both fresh thrombus and organized thrombus.

CONCLUSIONS

In at least 50% of patients with acute STEMI, coronary thrombi were days or weeks old. This indicates that sudden coronary occlusion is often preceded by a variable period of plaque instability and thrombus formation, initiated days or weeks before onset of symptoms.

More fibrosis and thrombotic complications but similar expression patterns of markers for coagulation and inflammation in symptomatic plaques from DM2 patients

OBJECTIVE

One of the possible pathological mechanisms behind the increased vascular injury in diabetes mellitus type 2 (DM2) is the formation of advanced glycation end products (AGEs). The aim of this study was to investigate whether the presence of AGEs and specific markers for coagulation and inflammation in symptomatic atherosclerotic plaques from DM2 patients differs from plaques from nondiabetics.

METHODS AND RESULTS

Carotid atherectomies were obtained from DM2 patients (n=11) and controls without DM2 matched for age and other cardiovascular risk factors (n=12) who were treated for symptomatic carotid artery stenosis. Plaques were graded according to the American Heart Association classification of lesions. More fibrosis and more thrombotic complications (p=0.007) were observed in carotid atherectomies from DM2 patients. Percentages of immunostained smooth muscle cells and macrophages in the lesions, quantified planimetrically, did not differ between the two groups. No differences were found in the immunostaining for T cells, tissue factor (TF), endothelial protein C receptor (EPCR), nuclear factor kappaB, and the AGE carboxymethyllysine.

CONCLUSIONS

These findings demonstrate that DM2 is associated with increased plaque complications; however, a local changed presence of AGEs, TF, and EPCR seems not to be involved in this end stage of atherosclerosis.

Increased incidence of hypercoagulability in patients with leg ulcers caused by leukocytoclastic vasculitis

Vasculitis is a rare cause of leg ulceration. It is unclear why severe skin infarction develops in some patients with vasculitis, whereas others have only mild symptoms such as purpura, erythema, or urticaria. A coincidence of vasculitis and hypercoagulability may lead to more extensive thrombotic occlusion and hence explain the occurrence of large ulcers in a subset of patients. Our aim was to investigate whether patients with vasculitis ulcers have an increased incidence of hypercoagulability. Thirteen consecutive patients admitted to the hospital with necrotic ulcers caused by histologically confirmed vasculitis were screened for clotting disorders. In 7 of 13 patients (53%), hypercoagulable conditions were found. Five patients had factor V Leiden (38%), and 2 had lupus anticoagulant (15%). The normal frequency of these conditions is 5% to 6% and 3.6%, respectively. These data indicate that there is an increased incidence of hypercoagulable disorders in patients with vasculitis ulcers. We recommend screening these patients routinely for hypercoagulability.

Differential localisation of the renin–angiotensin system in de-novo lesions and in-stent restenotic lesions in in-vivo human coronary arteries

OBJECTIVE

Different components of the renin-angiotensin system (RAS) have been demonstrated in atherosclerotic plaques. However, the involvement of the RAS in in-stent restenosis is not clear. We studied the differential immunolocalisation of angiotensin converting enzyme (ACE) and the angiotensin II type 1 (AT1) receptor in de-novo stenotic lesions and in-stent restenotic lesions in human coronary arteries.

METHODS

Using a pullback atherectomy catheter, biopsies from de-novo coronary lesions (n=19) and in-stent restenotic lesions (n=19) were obtained. The biopsies were immunostained for vascular smooth muscle cells (VSMCs), macrophages, ACE and the AT1 receptor.

RESULTS

In biopsies from de-novo stenotic lesions ACE-positive macrophages were more numerous than in in-stent restenotic lesions (P=0.002). Moreover, in the latter lesions, ACE-positive macrophages decreased when the time interval of stent implantation was longer. On the other hand, in-stent restenotic lesions contained predominantly young VSMCs, which abundantly expressed AT1 receptors.

CONCLUSIONS

Lesional ACE expression is not a prominent feature of in-stent restenotic lesions. In contrast, AT1 receptors are abundantly expressed on young VSMCs. In de-novo lesions ACE and AT1 receptors were found on macrophages and VSMCs, which were present in all specimens.

Longstanding obliterative panarteritis in Kawasaki disease: lack of cyclosporin A effect

Kawasaki disease is a childhood vasculitis of medium-sized vessels, affecting the coronary arteries in particular. We have treated a therapy-resistant child who met all diagnostic criteria for Kawasaki disease. After the boy was given intravenous immunoglobulins and salicylates, as well as several courses of pulsed methylprednisolone, disease recurred and coronary artery lesions became progressively detectable. Cyclosporin A was started and seemed clinically effective. In contrast to the positive effect on inflammatory parameters, ie, C-reactive protein and white blood cell counts, a novel plasma marker for cytotoxicity (granzyme B) remained elevated. Coronary disease progressed to fatal obstruction and myocardial infarction. Echocardiography, electrocardiograms, and myocardial creatine phosphokinase did not predict impending death. At autopsy an obliterative panarteritis was observed resulting from massive fibrointimal proliferation, affecting the aorta and several large and medium-sized arteries. Immunophenotypic analysis of the inflammatory infiltrates in arteries revealed mainly granzyme-positive cytotoxic T cells and macrophages in the intima and media, as well as nodular aggregates of T cells, B cells, and plasma cells in the adventitia of affected arteries. These findings further endorse the role of specific cellular and humoral immunity in Kawasaki disease. Unremitting coronary arteritis and excessive smooth muscle hyperplasia resulted in coronary occlusion despite the use of cyclosporin A.

Value of diagnostic techniques for cutaneous leishmaniasis

BACKGROUND

Traditional diagnostic tests, ie, smear, culture, and histopathology of a skin biopsy specimen, are not always conclusive in patients with a clinical diagnosis of cutaneous leishmaniasis (CL).

OBJECTIVE

Our purpose was to find out if a polymerase chain reaction (PCR) specific for Leishmania organisms might be more sensitive than the traditional diagnostic techniques, thereby decreasing the number of false-negative diagnoses.

METHODS

In a prospective study, smear, culture, and histopathology of skin biopsy specimens from 46 patients with a possible diagnosis of CL were compared with PCR specific for Leishmania. In addition, the Montenegro test as a measure of cellular immunity against the Leishmania parasite was performed. Proven CL was defined as a case in which at least 1 of the 3 traditional tests showed the presence of Leishmania parasites.

RESULTS

Of our 46 patients, 22 had leishmaniasis. Of the traditional tests, culture was the most sensitive but there were no statistically significant differences between the sensitivities of the various tests. PCR results were positive in all cases of proven leishmaniasis. Moreover, 3 patients with the clinical diagnosis of CL and negative findings on traditional tests had positive PCR results. Only 1 patient with a strong clinical suggestion of CL and positive Montenegro test results had negative PCR findings; this patient also had negative smear, culture, and histopathology results.

CONCLUSION

PCR appears to be the most sensitive single diagnostic test for CL.

Association between complex coronary artery stenosis and unstable angina and the extent of plaque inflammation

PURPOSE

Patients with unstable coronary syndromes often have complex morphology of coronary stenoses at angiography. We evaluated the association between qualitative assessment of coronary stenoses and plaque inflammation determined by immunohistochemistry.

METHODS

A total of 79 patients with unstable (n = 46) or stable angina (n = 33) underwent directional coronary atherectomy for culprit lesions. Qualitative analysis of coronary angiograms was performed using a modified Ambrose classification. Coronary lesions were categorized as either simple (concentric and eccentric type I, n = 29) or complex (eccentric type II and multiple irregularities, n = 50). Cryostat sections of retrieved atherosclerotic specimens were stained immunohistochemically with monoclonal antibodies, alpha-actin (smooth muscle cells), CD68 (macrophages), and CD3 (T lymphocytes). The extent of atherosclerotic inflammation within each coronary lesion was determined by the percentage of immunopositive macrophages per total tissue area (including smooth muscle cells) and the number of T lymphocytes per mm(2).

RESULTS

The mean (+/- SD) percentage of macrophages in atherectomy specimens from patients with unstable angina was greater than in specimens from patients with stable angina (21% +/- 14% vs. 13% +/- 10%, P = 0.01); similar results were seen when complex coronary lesions were compared with simple lesions (23% +/- 13% vs. 9% +/- 8%, P <0.001). In multivariate linear regression models, the combination of unstable angina and lesion complexity was strongly associated with the percentage of plaque macrophages.

CONCLUSION

The extent of atherosclerotic plaque inflammation is associated with angiographic grading of coronary lesion complexity and unstable angina.

Increased expression of T cell activation markers (CD25, CD26, CD40L and CD69) in atherectomy specimens of patients with unstable angina and acute myocardial infarction

Atherosclerotic plaques contain a chronic immune mediated inflammation in which T cells play an important role. A previous study revealed that the numbers of interleukin-2 receptor-positive T cells is increased in culprit lesions of patients with acute coronary syndromes; a finding of considerable interest since it indicates a recent change in the intraplaque T cell mediated immune response. Confirmation of this observation is important, because it could provide insight into the onset of the acute event. We have, therefore, expanded our earlier work by using a panel of different T cell activation markers (CD25, CD26, CD40L, CD69). The study is based on 58 culprit lesions from patients who underwent coronary atherectomy. There were four groups of patients: chronic stable angina (n=13), stabilized unstable angina (n=16), refractory unstable angina (n=15), and acute myocardial infarction (AMI; n=14). Activated T cells were expressed as a percentage of the total of CD3-positive cells. CD25, CD26, CD40L, and CD69/CD3 percentages increased with the severity of the coronary syndrome. In patients with AMI all percentages were significantly higher than in patients with chronic stable angina. CD25, CD26, CD40L, and CD69/CD3 percentages in patients with an unstable condition (refractory unstable angina and AMI) were significantly higher than those in patients with a stable condition (chronic stable or stabilized unstable angina) The finding that the percentage of T cells with recent onset activation is significantly increased in the culprit lesions of patients with acute coronary syndromes suggests strongly that a recent change in pathogenic stimulation has occurred leading to local T cell activation.

Compound heterozygosity for mutations (W156X and R225W) in SCN5A associated with severe cardiac conduction disturbances and degenerative changes in the conduction system

Cardiac conduction defects associate with mutations in SCN5A, the gene encoding the cardiac Na+ channel. In the present study, we characterized a family in which the proband was born in severe distress with irregular wide complex tachycardia. His older sister died at 1 year of age from severe conduction disease with similarly widened QRS-complexes. Mutational analysis of SCN5A in the proband demonstrated compound heterozygosity for a nonsense mutation (W156X), inherited from the father, and a missense mutation (R225W), inherited from the mother. Genotyping on DNA extracted from tissue from the deceased sibling revealed the same SCN5A genotype. Injection of cRNA encoding the W156X mutation in Xenopus oocytes did not produce any current. The R225W substitution neutralizes the third Arg residue within the voltage-sensing segment of domain I. Expression studies showed that this mutation leads to a severe reduction in I(Na) and is also associated with gating changes. Histological examination of the heart from the deceased sibling revealed changes consistent with a dilated type of cardiomyopathy and severe degenerative abnormalities of the specialized conduction system. The occurrence of compound heterozygosity for these two mutations implies that the proband carries solely severely dysfunctional cardiac Na+ channels. This explains his severe phenotype and that of his deceased sister who had been a carrier of the same genotype. The morphological changes within the heart of the deceased sibling may have occurred secondary to the Na+ channel abnormality and contributed to the severity of the disorder in this individual.

Neutrophil infiltration of culprit lesions in acute coronary syndromes

BACKGROUND

Neutrophils in unstable atherosclerotic lesions have not received much consideration, despite accumulating evidence suggesting a link between systemic inflammation and acute coronary syndromes.

METHODS AND RESULTS

Coronary artery segments were obtained at autopsy from 13 patients with acute myocardial infarction (AMI); 8 had a ruptured and 5 an eroded plaque. Patients (n=45) who had died of noncardiovascular diseases served as reference. Atherectomy specimens were obtained from 35 patients with stable angina pectoris (SAP) and from 32 patients with unstable angina pectoris (UAP). Antibodies against CD66b, elastase, myeloperoxidase, and CD11b identified neutrophils; CD10 identified neutral endopeptidase (NEP). CD66b-positive and NEP-positive neutrophils were counted and expressed as a number per square millimeter of tissue. All specimens with plaque rupture or erosion showed distinct neutrophil infiltration; the number did not differ between ruptured and eroded plaques. However, the number of NEP-positive neutrophils was significantly higher (P<0.0001) in ruptured plaques than in eroded plaques. UAP patients showed neutrophils in 14 of 32 culprit lesions; in SAP only 2 of 35 lesions contained neutrophils. The number of neutrophils and NEP-positive cells in patients with UAP was significantly higher (neutrophils, P<0.0005; NEP-positive cells, P<0.005) than in patients with SAP.

CONCLUSIONS

The observations suggest that neutrophil infiltration is actively associated with acute coronary events. The high number of NEP-positive neutrophils in ruptured plaques, compared with eroded plaques, may reflect differences in the underlying pathophysiological mechanisms.

Hepatocyte growth factor triggers signaling cascades mediating vascular smooth muscle cell migration

A key event in neointima formation and atherogenesis is the migration of vascular smooth muscle cells (VSMCs) into the intima. This is controlled by cytokines and extracellular matix (ECM) components within the microenvironment of the diseased vessel wall. At present, these signals have only been partially identified. In this study, we demonstrate that Met, the receptor tyrosine kinase for hepatocyte growth factor (HGF), is expressed on VSMCs isolated from the intima of atherosclerotic plaques of carotid arteries. Stimulation with HGF led to activation of Met as well as to activation of PI3-K, PKB/Akt, MEK, and the MAP kinases Erk1 and -2. Moreover, HGF induced lamellipodia formation, a characteristic feature of motile cells, and promoted VSMC migration across fibronectin-coated filters. The HGF-induced cell migration was mediated by beta1 integrins and required PI3-K activation. Our results suggest a role for the HGF-Met signaling pathway in the pathogenesis of atherosclerosis and restenosis.

Multiple complementary transcripts of pCMa1, a novel gene located at chromosome 11p15.1-2, and melanocytic cell transformation

The cDNA clone pCMa1 (0.45 kb) is one of the 12 novel cDNAs, previously identified when comparing RNA expression profiles of melanocytes, naevus cells, and non-metastatic melanoma cells. This clone did not reveal a unique long open reading frame. The pCMa1 gene localized to the distal, telomere proximal region on the short arm of chromosome 11.p15.1-2. Northern blot analyses with single-stranded cRNA probes revealed the presence of various complementary pCMa1 transcripts of different lengths, which are not enriched in the poly(A)(+) RNA fraction. The arbitrarily defined plus strand (used as a probe) mainly hybridized to 0.45 kb and 4.0 kb minus transcripts in total RNA samples, and the minus strand (used as a probe) hybridized to a major plus transcript of 4.0 kb. By RNA in situ hybridization, the highest levels of the plus transcripts were observed in melanocytic naevi (12/12), particularly in congenital naevi, whereas normal skin melanocytes (12/12) were negative. pCMa1 plus transcripts were detected in naevus cell nests (100%) near the dermo-epidermal junction. Expression, however, diminished to some extent in the deeper parts of the melanocytic naevi. Although most of the cutaneous primary melanoma lesions (11/15) showed detectable, but variable levels of plus transcripts of pCMa1 in the papillary to reticular dermis, not more than 10% of the melanoma cells were positive. The majority of melanoma metastases (6/7) were negative, while the positive lesion originated from a patient with a positive primary melanoma. Furthermore, plus transcripts were present in the nuclei of non-metastatic melanoma cells in culture, whereas metastatic cells showed elevated expression both in the nucleus and in the cytoplasm. Briefly, the data show transient up-regulation of pCMa1 in neoplastic progression of melanocytic cells, with peak levels occurring during naevus stages, and suggest that pCMa1 is a molecular marker in melanocytes for the early changes from the proliferating phenotype to malignant transformation.

Platelet involvement in cutaneous small vessel vasculitis

BACKGROUND

Secretory products of platelets serve important functions in inflammation and thrombosis. Participation of platelets in the tissue reaction associated with cutaneous small vessel vasculitis has not yet been evaluated, so we systematically investigated the presence of platelet aggregates in inflamed microvessels.

METHODS

Thirty-six biopsies containing vasculitis and 18 biopsies with perivascular or interface type dermatitis were reviewed and adjacent sections were immunohistochemically stained with anti-CD61 antibody recognizing GPIIbIIIa receptors on platelets and with anti-von Willebrand factor (anti-vWF) antibody.

RESULTS

Platelet aggregates were observed in 27 (75%) of the vasculitis biopsies and three (16.7%) of the perivascular dermatitis biopsies, of which two (11%) had traumatic vessel damage. In all vasculitis cases, platelet clumps were associated with diffuse immunostaining of the perivascular stroma with the initiator of platelet aggregation anti-vWF. In the non-vasculitis type of dermatitis anti-vWF staining remained strictly limited to the cytoplasm of endothelial cells in 10 cases, and in eight cases there was also slight diffuse perivascular staining, albeit less extensively than in vasculitis cases.

CONCLUSION

Formation of platelet aggregates appears to play a thus far unrecognized role in cutaneous small vasculitis. Secretory products of platelets will likely contribute to the inflammatory response and tissue damage in vasculitis. Moreover, platelet immunohistochemistry may be helpful in the diagnosis of microvascular damage in paraffin sections.