Phospholipase Cε insufficiency causes ascending aortic aneurysm and dissection

Phospholipase Cε (PLCε) is a phospholipase C isoform with a wide range of physiological functions. It has been implicated in aortic valve disorders, but its role in frequently associated aortic disease remains unclear. To determine the role of PLCε in thoracic aortic aneurysm and dissection (TAAD) we used PLCε-deficient mice, which develop aortic valve insufficiency and exhibit aortic dilation of the ascending thoracic aorta and arch without histopathological evidence of injury. Fourteen days of infusion of Plce1+/+ and Plce1-/- mice with angiotensin II (ANG II), which induces aortic dilation and dissection, led to sudden death secondary to ascending aortic dissection in 43% of Plce1-/- versus 5% of Plce1+/+ mice (P < 0.05). Medial degeneration and TAAD were detected in 80% of Plce1-/- compared with 10% of Plce1+/+ mice (P < 0.05) after 4 days of ANG II. Treatment with ANG II markedly increased PLCε expression within the ascending aortic adventitia. Total RNA sequencing demonstrated marked upregulation of inflammatory and fibrotic pathways mediated by interleukin-1β, interleukin-6, and tumor necrosis factor-α. In silico analysis of whole exome sequences of 258 patients with type A dissection identified 5 patients with nonsynonymous PLCE1 variants. Our data suggest that PLCε deficiency plays a role in the development of TAAD and aortic insufficiency.NEW & NOTEWORTHY We describe a novel phenotype by which PLCε deficiency predisposes to aortic valve insufficiency and ascending aortic aneurysm, dissection, and sudden death in the setting of ANG II-mediated hypertension. We demonstrate PLCE1 variants in patients with type A aortic dissection and aortic insufficiency, suggesting that PLCE1 may also play a role in human aortic disease. This finding is of very high significance because it has not been previously demonstrated that PLCε directly mediates aortic dissection.

Altered microRNAs in bicuspid aortic valve: a comparison between stenotic and insufficient valves

BACKGROUND AND AIM OF THE STUDY

Bicuspid aortic valve (BAV), the most common form of congenital heart disease, is a leading cause of aortic stenosis (AS) and aortic insufficiency (AI). AS is typically caused by calcific valve disease. Recently, microRNAs (miRNAs) have been shown to modulate gene expression. The study aim was to examine the miRNAs that were altered in the aortic valve leaflets of patients with AS compared to those in patients with AI. In-vitro experiments were also carried out to determine if these miRNAs could modulate calcification-related genes.

METHODS

Aortic valve samples (fused and unfused leaflets) were collected from nine male patients (mean age 44.9 +/- 13.8 years) undergoing aortic valve replacement (AVR). PIQOR miRXplore Microarrays containing 1,421 miRNAs were used and hybridized to fused leaflet samples labeled with Cy5; unfused samples were used as controls and labeled with Cy3. A quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to validate the miRNA array results. Cultured human aortic valve interstitial cells (AVICs) were treated with miRNA mimics, and qRT-PCR was carried out to determine any changes in mRNAs.

RESULTS

By microarray analysis, seven miRNAs were shown to be statistically different between the AS and AI patients. In the stenotic samples, the MiR-26a and miR-195 levels were shown (by qRT-PCR) to be reduced by 65% and 59%, respectively (p < 0.05), and MiR-30b to be reduced by 62% (p < 0.06). Human AVICs treated with miR-26a or miR-30b mimics showed decreased mRNA levels of calcification-related genes. MiR-26a repressed BMP2 by 36%, alkaline phosphatase (ALPL) by 38%, and SMAD1 by 26%, while MiR-30b reduced the expression of SMAD1 by 18% and of SMAD3 by 12%. In contrast, miR-195-treated AVICs had increased mRNA levels of calcification-related genes, such as BMP2 by 68% and RUNX2 by 11%.

CONCLUSION

MiR-26a, miR-30b, and miR-195 were each decreased in the aortic valves of patients requiring AVR due to AS, compared to those requiring replacement due to AI. These miRNAs appear to modulate calcification-related genes in vitro.

Unknown ankylosing spondylitis with only cardiac involvement in patient with surgical indication: Call for patient and family members immunological screening

Aortic regurgitation (AR) and first-degree atrioventricular heart block (FDAVB) are encountered in ankylosing spondylitis (AS). This rheumatological disease also presents in 90% of the cases an immunogenetic marker that is Human Leucocyte Antigen-B27 (HLA-B27). In this report we describe a case of a patient presenting with AR, FDAVB, aneurysm and thinning of the ascending aortic wall, aneurysm of the sinuses of Valsalva and inferior myocardial infarction-like electrocardiographic pattern with unknown cardiac AS and absence of other AS-related systemic manifestations.

Novel NOTCH1 mutations in patients with bicuspid aortic valve disease and thoracic aortic aneurysms

OBJECTIVES

Bicuspid aortic valve is a common condition and is associated with a significantly increased risk of developing thoracic aortic aneurysms and acute aortic dissection. Patient-specific prediction of the risk of developing thoracic aortic aneurysm, however, is imprecise. We hypothesize that genotypic variations in patients with bicuspid aortic valves contribute to this observed variability in aortic phenotype. We, therefore, investigated the potential relationship between mutations in regions of NOTCH1 recently reported to be associated with bicuspid aortic valve and the phenotype of bicuspid aortic valve and thoracic aortic aneurysms in unrelated patients undergoing surgical repair.

METHODS

We performed a targeted mutational analysis of NOTCH1 using genomic DNA from 48 unrelated subjects with concomitant bicuspid aortic valve and thoracic aortic aneurysm using denaturing high-performance liquid chromatography and DNA sequencing. We focused on exons in which mutations associated with bicuspid aortic valve have been reported previously. Results were compared with control subjects with trileaflet aortic valves (n = 94), bicuspid aortic valves, and normal aortas (n = 22) and in subjects with tricuspid aortic valves and thoracic aortic aneurysms (n = 28).

RESULTS

Four unique, nonsynonymous (3 novel) variants were identified in 5 (10.4%) of 48 patients with concomitant bicuspid aortic valves and thoracic aortic aneurysms compared with only 3 (2.1%) of 144 control subjects (P = .02). Of these, 2 novel missense mutations, A1343V and P1390T, were observed only in patients with bicuspid aortic valves and tricuspid aortic aneurysms.

CONCLUSIONS

This targeted analysis involving NOTCH1 exons previously implicated in familial and sporadic bicuspid aortic valve demonstrates overrepresentation of NOTCH1 missense variants among patients with bicuspid aortic valves and thoracic aortic aneurysms. Identification of aneurysm-predisposing susceptibility genes may lead to gene-directed surgical therapy of the ascending aorta for patients with bicuspid aortic valves.

Heritable diseases of the blood vessels

Four inherited disorders known to effect major arteries will be discussed, including Marfan syndrome (MS), Ehlers-Danlos syndrome (EDS), bicuspid aortic valve (BAV) and nonsyndromic familial aortic dissection. Recent advances in understanding their pathophysiology are presented, and how this knowledge impacts on diagnosis, prevention and treatment is discussed.

Influence of angiotensin-converting enzyme gene insertion/deletion polymorphism on rheumatic valve involvement, valve severity and subsequent valve calcification

BACKGROUND AND AIM OF THE STUDY

The relationship between the severity of chronic rheumatic heart disease (RHD) and predisposing factors is unknown, and genetic predictors for severe scarring and calcification of the mitral valve are not well defined. A high angiotensin-converting enzyme (ACE) activity has been demonstrated in valve tissue. Thus, a case-control study was conducted to investigate any possible relationship between ACE gene polymorphisms and chronic mitral valve disease severity and calcification.

METHODS

This case-control study included 82 patients (24 males, 58 females; mean age 40.3 +/- 14.7 years) with chronic rheumatic mitral valve, and 154 control subjects (53 males, 101 females; mean age 43.4 +/- 13.4 years). ACE gene insertion/deletion (I/D) polymorphisms were identified using polymerase chain reaction methods.

RESULTS

Among RHD subjects, 31 (30.6%) were D/D, 25 (32.7%) were I/D, and 26 (18.8%) were I/I. Among controls, 57 (57.4%) were D/D, 69 (61.3%) were I/D, and 28 (35.2%) were I/I. The frequency of ACE I/I genotype was higher in RHD subjects than in controls (chi2 = 7.4, df = 2, p < 0.030; D/D versus I/D versus I/I), or (chi2 = 5.5, df = 1, p < 0.019; DD + ID versus II). Predisposition to RHD was significantly less frequent in the D/D genotype. There was no statistically significant difference in the genetic analysis of RHD with respect to mitral valve score, severity of mitral regurgitation and left atrial diameter. Mitral valve calcification was significantly associated with a higher frequency of I/I genotype and I/D genotype than D/D genotype alone (chi2 = 6.2, df = 2, p = 0.043). The ACE I/I genotype was associated with a predisposition to a greater risk of severe calcific valve disease.

CONCLUSION

The ACE I/I genotype is more common in patients with rheumatic valve disease than in the normal population. This suggests that the ACE gene polymorphism may be involved in the pathogenesis of rheumatic heart disease.

Myocardial hypertrophy is not a prerequisite for changes in early gene expression in left ventricular volume overload

Currently it is not certain whether hypertrophy or the underlying disease is the primary trigger of the alterations in early gene expression in the progression of cardiac disease to end-stage heart failure. In this study, we tested the notion that in left ventricular overload disorders, the changes in early gene expression in the progression to heart failure is independent of the manifestation of cardiac hypertrophy. We compared the expression of the early genes c-fos, c-myc, and c-jun in six dilated cardiomyopathic hearts (DCM) and 15 patients with left ventricular volume overload (VOL) resulting from mitral/aortic regurgitation and no significant stenosis or hypertrophic manifestations, using eight healthy donor hearts as controls. In VOL, c-myc was elevated by 88% (P < 0.01) in the left ventricle, 46% in the right ventricle, onefold (P < 0.01) in the left atrium, and 54% (P < 0.05) in the right atrium, while in DCM, it was increased by 71% (P < 0.02), 55%, 48% (P < 0.05) and 91% (P < 0.05), respectively. Similarly, c-jun was elevated by 41% (P < 0.01) in the left ventricle, 39% (P < 0.05) in the right ventricle, 83% (P < 0.02) in the left atrium and 21% in the right atrium in VOL, while in DCM it was elevated by 13% in the left ventricle, 29% in the left atrium, and 41% in the right atrium, but decreased by 13% in the right ventricle. In contrast, c-fos was slightly decreased in the left ventricle and atrium of both DCM and VOL, and in left atrium of the VOL group, but remained unchanged in the other myocardial chambers. These results show that, in the human myocardium, the three early genes are regulated differently, possibly in disease- and chamber-specific fashions, and manifestation of left ventricular hypertrophy is not a prerequisite for the elevation in their expression in left ventricular overload disorders.

Effectiveness of β-Blockade in Experimental Chronic Aortic Regurgitation

BACKGROUND

Past studies have suggested that the adrenergic system becomes abnormally activated in chronic volume overload, such as in severe aortic valve regurgitation (AR). However, the effectiveness of agents directed against this adrenergic activation has never been adequately tested in chronic AR. We therefore tested the effects of metoprolol treatment on the left ventricular (LV) function and remodeling in severe chronic AR in rats.

METHODS AND RESULTS

Severe AR was created in adult male Wistar rats by retrograde puncture of the aortic leaflets under echocardiographic guidance. Two weeks later, some animals received metoprolol treatment (25 mg/kg) orally for 24 weeks, and some were left untreated. LV dimensions, ejection fraction, and filling parameters were evaluated by echocardiography. Hearts were harvested at 1, 2, 14, and 180 days for the evaluation of hypertrophy, beta-adrenergic receptor status, and extracellular matrix remodeling. We found that metoprolol treatment prevented LV dilatation and preserved the ejection fraction and filling parameters compared with untreated animals. Metoprolol increased the expression of beta1-adrenoreceptor mRNA and reduced G protein receptor kinase 2 levels. Collagen I and III mRNA levels were reduced. Cardiac myocyte hypertrophy was also prevented.

CONCLUSIONS

In our experimental model of severe AR, metoprolol treatment had a significant beneficial global effect on LV remodeling and function. These results suggest that the adrenergic system is important in the development of volume-overload cardiomyopathy in AR and that adrenergic-blocking agents may play a role in the treatment of this disease.

Vesnarinone-Mediated Alterations of Gene Expression in Cardiac Fibroblasts from Aortic Regurgitant Hearts

Pathologic fibrosis precedes heart failure (CHF) and death in experimental aortic regurgitation (AR). Vesnarinone, a positively inotropic quinolone derivative, suppresses survival of fibroblasts (CF) from hearts with chronic experimental AR. To explore further the potential effects of vesnarinone on cardiac fibrosis in AR, we tested the hypothesis that vesnarinone suppresses gene expression induced by AR in CF. Differentially expressed genes were isolated by suppression subtractive hybridization (SSH) in CF from hearts of 2 New Zealand White rabbits with surgically induced AR compared with 2 normal rabbits. In cultured AR-CF treated with and without vesnarinone (4 doses, including the dose that had caused maximal survival suppression in cultured AR-CF), drug effect was assessed on expression of genes found to be up-regulated by AR. SSH, reverse Northern analysis, and Northern analysis indicated that at doses several orders of magnitude lower than those used for treatment in CHF vesnarinone significantly down-regulated 2 genes (thrombospondin 1, annexin II) up-regulated by AR. The study confirmed earlier findings of AR-mediated alteration in expression of genes that code for noncollagen extracellular matrix (ECM) proteins. Thus, in CF conditioned by exposure to AR, vesnarinone at relatively low doses suppresses genes coding for 2 noncollagen ECM proteins up-regulated by AR. These pharmacologic effects may underlie potentially therapeutic mitigation of fibrosis by vesnarinone.

Angiotensin-converting enzyme polymorphisms and their potential impact on left ventricular myocardial geometry after aortic valve surgery

BACKGROUND AND AIM OF THE STUDY

Genetic variants of the angiotensin-converting enzyme (ACE) cascade may influence left ventricular myocardial mass (LVMM) regression after aortic valve surgery. Postoperative long-term changes in LV indices were investigated in patients with asymptomatic aortic regurgitation (AR) and symptomatic aortic stenosis (AS) and related to alleles of ACE polymorphisms.

METHODS

A total of 96 patients was included in the study, 21 with class IIa AR (22%) and 75 with class I AS (78%) recommendations for surgery. Patients were evaluated for demographic risk factors and underwent a thorough clinical examination including 3-D cardiac imaging by ultrafast-computed tomography. Genomic DNA was isolated for genotyping.

RESULTS

AR patients were younger (55.8 +/- 8.9 versus 64 +/- 9.1 years, p = 0.0014), had a larger body surface area (1.92 +/- 0.21 versus 1.82 +/- 0.19 m2, p = 0.039), and were more likely to be asymptomatic (myocardial infarction, p = 0.04; syncope, p = 0.0099; thromboembolism, p = 0.03; NYHA class IV, p = 0.04). Postoperatively, the reduction in absolute LVMM (from 297.1 +/- 52.6 to 190.1 +/- 57.1 g versus 214.4 +/- 55.7 to 143.8 +/- 40.0 g; pT = 0.0000001) and indexed LVMM (from 156.0 +/- 31.7 to 99.3 +/- 28.4 g/m2 versus 118.7 +/- 28.3 to 79.3 +/- 20.6 g/m; pT = 0.0000001) over time was more significant in AR patients, but never reached normal values. Enforced ACE inhibitor medication resulted in significantly higher postoperative indexed LVMM differences in homozygote DD patients compared to AR patients with II/ID alleles of ACE 16 ins/del polymorphism.

CONCLUSION

AR patients showed a statistically significant decrease in absolute/indexed LVMM during follow up, but never achieved LV mass recovery compared to standard values or to values in patients undergoing aortic valve replacement for AS. The benefits of ACE inhibitors were observed among AR patients with homozygote DD alleles of ACE 16 ins/del polymorphism.

HLA class II associations with rheumatic heart disease among clinically homogeneous patients in children in Latvia

Genetic control of immune reactions has a major role in the development of rheumatic heart disease (RHD) and differs between patients with rheumatic fever (RF). Some authors think the risk of acquiring RHD is associated with the HLA class II DR and DQ loci, but other views exist, due to the various HLA-typing methods and ways of grouping cases. Our goal was to determine the relations between HLA class II alleles and risk of or protection from RF in patients with relatively homogeneous clinical manifestations. A total of 70 RF patients under the age of 18 years were surveyed in Latvia. HLA genotyping of DRB1*01 to DRB1*18 and DQB1*0201-202, *0301-305, *0401-402, *0501-504, and *0601-608 was performed using polymerase chain reaction sequence-specific primers. Data for a control group of 100 healthy individuals typed for HLA by the same method were available from the databank of the Immunology Institute of Latvia. Of the RF patients, 47 had RHD and 8 had Sydenham's chorea. We concluded that HLA class II DRB1*07-DQB1*0401-2 and DRB1*07-DQB1*0302 could be the risk alleles and HLA class II DRB1*06 and DQB1*0602-8, the protective ones. Patients with mitral valve regurgitation more often had DRB1*07 and DQB1*0401-2, and patients with multivalvular lesions more often had DRB1*07 and DQB1*0302. In Sydenham's chorea patients, the DQB1*0401-2 allele was more frequent. Genotyping control showed a high risk of RF and RHD in patients with DRB1*01-DQB1*0301-DRB1*07-DQB1*0302 and DRB1*15-DQB1*0302-DRB1*07-DQB1*0303.

Role of inadequate adaptive left ventricular hypertrophy in the genesis of mitral regurgitation in patients with severe aortic stenosis: implications for its prevention

BACKGROUND AND AIM OF THE STUDY

Mitral regurgitation (MR) is frequent in patients with severe calcific aortic stenosis (AS). This complicates not only the clinical course of AS, but also its surgical management. The aim of the present study was to investigate the mechanism of genesis of MR in patients with severe AS.

METHODS

The echocardiographic database was searched for subjects with severe AS defined as a calculated (continuity equation) aortic valve area < 0.7 cm2. Patients with previous valve surgery were excluded; thus, the study group comprised 123 patients.

RESULTS

Among 123 patients (mean age 75 +/- 10 years) with severe AS, 54 (44%) had no MR, 37 (30%) had mild MR, 20 (16%) had moderate MR, and 12 (10%) had severe MR. Hence, moderate or severe MR was present in approximately 25% of patients. Patients with moderate or severe MR had a larger left ventricular (LV) end-diastolic diameter (5.1 +/- 1.0 versus 4.8 +/- 0.8 cm; p = 0.08), larger LV end-systolic diameter (3.8 +/- 1.2 versus 3.1 +/- 0.8 cm; p = 0.001), lower LV ejection fraction (40 +/- 16 versus 58 +/- 18%; p = 0.0001), higher degree of aortic regurgitation (p = 0.002), larger left atrial diameter (4.7 +/- 0.9 versus 4.1 +/- 0.6 cm; p = 0.001), lower LV free wall thickness (1.1 +/- 0.2 versus 1.3 +/- 0.4 cm; p = 0.05), and lower combined wall thickness (2.4 +/- 0.3 versus 2.7 +/- 0.5 cm; p = 0.02) and relative wall thickness (0.5 +/- 0.1 versus 0.6 +/- 0.1 cm; p = 0.02). Both groups had similar degrees of AS and mitral annular calcification.

CONCLUSION

MR in severe AS is associated with a larger LV size and lesser wall thickness, and this may result from failure of adequate adaptive LV hypertrophy necessitated by the pressure overload imposed by AS. This might have important clinical implications in terms of timing of aortic valve replacement before the left ventricle begins to dilate, and also in the choice of pharmacologic therapy that may modulate the adaptive response of the left ventricle.

Identification of mutations in the COL7A1 gene in a proband with mild recessive dystrophic epidermolysis bullosa and aortic insufficiency

We report the clinical and molecular findings in a patient with a mild form of recessive dystrophic epidermolysis bullosa and aortic insufficiency. To our knowledge, this is the first report of association between dystrophic epidermolysis bullosa and abnormalities of the aortic valve. Analysis of the COL7A1 gene has revealed two new mutations, a 20-bp duplication and a splice site mutation.

Modified aortic root remodeling for annuloaortic ectasia with abnormal coronary take-off

The abnormality of coronary arterial take-off is a limiting factor for a successful aortic valve sparing procedure. We present a 13-year-old boy, with Marfan syndrome and annuloaortic ectasia, whose coronary take-off was found to be abnormal during surgery. Two adjacent coronary orifices were located in the left coronary sinus and very close to the right-left commissure. A modified aortic remodeling procedure was successfully performed without translocation of the coronary artery.

Genetic influences on aortic root size in American Indians: the Strong Heart Study

Aortic root dilatation is a major pathophysiological mechanism for aortic regurgitation and predisposes the aortic root to dissection or rupture. However, only a small proportion of the variance of aortic root size can be explained by its known clinical and demographic correlates. The present study was undertaken to determine the heritability of echocardiographically derived aortic root diameter in the American Indian participants in the second Strong Heart Study examination. Echocardiograms were analyzed in 1373 SHS participants who had > or =1 family member in the cohort. Heritability calculations were performed by using variance component analysis as implemented in SOLAR, a computer analysis program. In a polygenic model, the variables entered and identified as covariates of larger aortic root diameter were older age, male sex, and center (P<0.001), which accounted for 35% of the overall variability of aortic root diameter. After simultaneous adjustment was made for these significant covariates, the proportion of phenotypic variance due to additive genetic contribution or residual heritability (h2) was 0.51 (SE=0.08, P<0.001). Additionally, simultaneous adjustment for height, weight, and systolic and diastolic BPs yielded slightly lower residual h2 of aortic root diameter (h2=0.44, SE=0.08, P<0.001), which accounted for 26% of the overall variance of aortic root size. Because center effects were identified as significant covariates in the analyses, h2 analyses were performed separately in Arizona, Oklahoma, and North/South Dakota centers, which confirmed that a significant proportion of the phenotypic variance of aortic root diameter is due to additive genetic contribution. Heredity explains a substantial proportion of the variability of aortic root size that is not accounted for by age, sex, body size, and blood pressure. Echocardiographic screening of family members with aortic root dilatation may identify other individuals predisposed to aortic dissection or rupture.

Myocardial fibrosis in chronic aortic regurgitation: molecular and cellular responses to volume overload

BACKGROUND

Myocardial fibrosis is common in patients with chronic aortic regurgitation (AR). Experimentally, fibrosis with disproportionate noncollagen extracellular matrix (ECM) elements precedes and contributes to heart failure in AR.

METHODS AND RESULTS

We assessed [3H]-glucosamine and [3H]-proline incorporation in ECM, variations in cardiac fibroblast (CF) gene expression, and synthesis of specific ECM proteins in CF cultured from rabbits with surgically induced chronic AR versus controls. To determine whether these variations are primary responses to AR, normal CF were exposed to mechanical strain that mimicked that of AR. Compared with normal CF, AR CF incorporated more glucosamine (1.8:1, P=0.001) into ECM, showed fibronectin gene upregulation (2.0:1, P=0.02), and synthesized more fibronectin (2:1 by Western blot, P<0.06; 1.5:1 by affinity chromatography, P=0.02). Proline incorporation was unchanged by AR (1.1:1, NS); collagen synthesis was unaffected (type I, 0.9:1; type III, 1.0:1, NS). Normal CF exposed to cyclical mechanical strain during culture showed parallel results: glucosamine incorporation increased with strain (2.1:1, P<0.001), proline incorporation was unaffected (1.1:1, NS), fibronectin gene expression (1.6:1, P=0.07) and fibronectin synthesis (Western analysis, 1.3:1, P<0.01; chromatography, 1.9:1, NS) were upregulated.

CONCLUSIONS

In AR, CF produce abnormal proportions of noncollagen ECM, specifically fibronectin, with relatively little change in collagen synthesis. At least in part, this is a primary response to strain imposed on CF by AR. Further study must relate these findings to the pathogenesis of heart failure in AR.

Genotype and phenotype analysis of 171 patients referred for molecular study of the fibrillin-1 gene FBN1 because of suspected Marfan syndrome

BACKGROUND

Marfan syndrome (MFS) is an underrecognized heritable connective tissue disorder resulting from mutations in the gene for fibrillin-1 (FBN1). Affected patients are at risk for aortic dissection and/or severe ocular and orthopedic problems. The diagnosis is primarily based on a set of well-defined clinical criteria (Ghent nosology). The age-related nature of some clinical manifestations and variable phenotypic expression may hinder the diagnosis, particularly in children. Molecular analysis may be helpful to identify at-risk individuals early and start prophylactic medical treatment. FBN1 mutations have also been reported in patients with Marfan-related conditions, but it is unknown what proportion of all FBN1 mutation carriers they represent.

METHODS

We reviewed the clinical and molecular data of 171 consecutive patients referred for FBN1 analysis because either MFS was diagnosed or they had signs suggestive of MFS. We compared the incidence of mutations in patients who fulfilled the clinical diagnostic criteria for MFS with those who did not.

RESULTS

Diagnostic criteria for MFS were fulfilled in 94 patients, 62 (66%) of whom had an FBN1 mutation. A significantly higher incidence of ectopia lentis was found in the patients with MFS with an FBN1 mutation vs those without (P=.04). Among the 77 patients who did not meet the criteria, an FBN1 mutation was found in 9 patients (12%). No correlation was found between the severity of the phenotype and the position and nature of the FBN1 mutation.

CONCLUSIONS

This study showed a significant difference in the number of FBN1 mutations between patients fulfilling and those not fulfilling the diagnostic criteria for MFS, which seems to be a good predictor of the presence of an FBN1 mutation. A comprehensive clinical evaluation is mandatory before establishing a definitive diagnosis. An FBN1 mutation analysis is helpful to identify individuals at high risk for MFS who need careful follow-up, particularly in families displaying phenotypic variability and in children.

Abnormal gene expression of cardiac fibroblasts in experimental aortic regurgitation

Extensive primary fibrosis precedes heart failure and death in experimental chronic aortic regurgitation. To seek the molecular basis for this observation, this study analyzed the RNA pool for genes that are up-or downregulated in aortic regurgitation fibroblasts. Differential display reverse transcriptase polymerase chain reaction was used to compare RNA extracted from cardiac fibroblasts isolated from three healthy New Zealand white rabbits and from three with aortic regurgitation. Using two base anchoring oligo d(T) primers (T11VN) together with arbitrary upstream primers, numerous differences in normal versus aortic regurgitation gene expression were apparent on differential display reverse transcriptase polymerase chain reaction. The aortic regurgitation cell cultures showed numerous differentially up-and downregulated genes compared with cell cultures of normal cardiac fibroblasts. The results showed that pathologic fibrosis in chronic experimental aortic regurgitation is associated with abnormal cardiac fibroblast gene expression, which may be pathogenic for the fibrous lesion.

Mice mutant for Egfr and Shp2 have defective cardiac semilunar valvulogenesis

Atrioventricular and semilunar valve abnormalities are common birth defects, but how cardiac valvulogenesis is directed remains largely unknown. During studies of genetic interaction between Egfr, encoding the epidermal growth factor receptor, and Ptpn11, encoding the protein-tyrosine-phosphatase Shp2, we discovered that Egfr is required for semilunar, but not atrioventricular, valve development. Although unnoticed in earlier studies, mice homozygous for the hypomorphic Egfr allele waved-2 (Egfrwa2/wa2) exhibit semilunar valve enlargement resulting from over-abundant mesenchymal cells. Egfr-/- mice (CD1 background) have similar defects. The penetrance and severity of the defects in Egfrwa2/wa2 mice are enhanced by heterozygosity for a targeted mutation of exon 2 of Ptpn11 (ref. 3). Compound (Egfrwa2/wa2:Ptpn11+/-) mutant mice also show premature lethality. Electrocardiography, echocardiography and haemodynamic analyses showed that affected mice develop aortic stenosis and regurgitation. Our results identify the Egfr and Shp2 as components of a growth-factor signalling pathway required specifically for semilunar valvulogenesis, support the hypothesis that Shp2 is required for Egfr signalling in vivo, and provide an animal model for aortic valve disease.

Reliability of transthoracic echocardiography in the assessment of aortic valve morphology: pathological correlation in 178 patients

OBJECTIVE

To examine patient characteristics affecting the utility of transthoracic echocardiography in determining aortic valve morphology, particularly for the diagnosis of congenital bicuspid aortic valve (BAV).

DESIGN

A retrospective comparison of preoperative echocardiographic determination of aortic valve morphology with pathological findings of the explanted valves.

SETTING

A tertiary referral centre.

PATIENTS

Consecutive patients who had aortic valve replacement between July 1994 and April 1996, and had preoperative echocardiograms.

RESULTS

Of 313 patients, 181 (58%) had preoperative echocardiography. Three of the valves were excluded because they were too fragmented for pathological determination of valvular morphology. In the remaining 178 patients, aortic valvular morphology was determined by echocardiography in 104 (58%). Multivariate analysis showed that echocardiography was successful less often in women (odds ratio 0.44, P = 0.03) and in patients with densely calcified valves (odds ratio 0.69, P = 0.02), whereas age had no effect (odd ratio 0.99, P = 0.42). In those with adequate echocardiographic images, echocardiography had both a high sensitivity (0.92) and a high specificity (0.96) for the diagnosis of BAV.

CONCLUSIONS

Echocardiography is a useful tool for the diagnosis of BAV, although suboptimal images may pose a problem in many patients, particularly women and patients with heavily calcified valves. When adequate images are obtained, transthoracic echocardiography can reliably identify aortic valvular morphology in most patients.

[Abdominal aortic aneurysm and annuloaortic ectasia in siblings with Marfan syndrome]

A combination of annuloaortic ectasia (AAE) and abdominal aortic aneurysm (AAA) appeared in siblings with Marfan syndrome is presented. The patients were a 53-year-old female and her younger brother. The brother died of arrhythmia twenty years before while waiting for surgical repair of AAE. His AAA and Marfan syndrome were ascertained at autopsy. The female patient received surgical repair for AAA and AAE subsequently. Pathologic study of the resected aneurysm revealed cystic medial necrosis. A combination of AAE and AAA developed in two members of a family with Marfan syndrome is extremely rare.

Acromicric dysplasia and geleophysic dysplasia: similarities and differences

We report on a girl with severe growth retardation, characteristic facies, short stubby hands and feet, progressive joint stiffness, mild aortic and mitral valve insufficiency, and normal intelligence. These features are compatible with the diagnosis acromicric dysplasia. The differential diagnosis with Moore-Federman syndrome and geleophysic dysplasia is discussed; major points to consider in differentiating these entities are the facial appearance, the aspect of the proximal femora, and the presence or absence of storage phenomena. The differences in pattern of inheritance are important in adequate patient care, especially in genetic counselling.

CONCLUSION

Acromicric dysplasia, geleophysic dysplasia, and Moore-Federman syndrome may be allelic forms of the same disorder or different disturbances of the same metabolic pathway.

Prevalence of cardiovascular malformations and association with karyotypes in Turner's syndrome

The aim of the study was to establish the prevalence of cardiovascular malformations in females with Turner's syndrome and analyse possible associations with the various karyotypes. One hundred and seventy nine of 393 females who had Turner's syndrome diagnosed in Denmark were examined. Complete chromosome analysis was available in all cases. Clinical examination, electrocardiography, and echocardiography including Doppler were performed. The distribution of the various karyotypes was 45,X, 58%; mosaic monosomy X, 35%; and structural abnormalities of the X chromosome, 7%. In 46 (26%) of the females a total of 69 cardiovascular malformations were found; aortic valve abnormality (18%) and aortic coarctation (10%) being the most common. There was a significant difference in the prevalence of cardiovascular malformations between 45,X and mosaic monosomy X (38% v 11%), primarily due to a significant difference in the prevalence of aortic valve abnormalities and aortic coarctation. Pulmonary valve abnormalities were seen only in females with mosaic monosomy X but the prevalence was low (3%). No patient with structural abnormalities of the X chromosome had cardiovascular malformations.

Mitral valve prolapse in persons with Down syndrome

This study was designed to determine the prevalence of mitral valve prolapse and aortic insufficiency in home-reared, young persons with Down syndrome. Of the 36 individuals (ages 20-32 years) enrolled in this study, 20 had abnormal echocardiographic findings. Thirteen patients had mitral valve prolapse, 3 had both mitral valve prolapse and aortic insufficiency, 2 had only aortic insufficiency, and 2 had other mitral valve disorders. In 14 of the 16 patients with mitral valve prolapse, a midsystolic click was heard. Theories of the pathogenesis and possible complications of mitral valve prolapse and its relationship to exercise and sport activities are discussed.

Familial calcification of aorta and calcific aortic valve disease associated with immunologic abnormalities

We report three patients of the same family with linear calcification of the ascending aorta, severe calcific mixed aortic valve disease associated with increased levels of globulins, lambda-chain gammopathy, an increased T4/T8 lymphocyte ratio, and other immunologic abnormalities. None of the patients had syphilis, atherosclerosis, abnormalities of calcium or phosphorus metabolism, lymphadenopathy, or other systemic diseases. It is postulated that these cases and some previously reported in the literature as idiopathic represent a distinct pathologic entity, familial or sporadic, in which localized vascular and valvular calcific disease is associated with an underlying immunologic disorder or autoimmune process.

Ventricular arrhythmias in Takayasu arteritis

We studied the prevalence, severity and clinical significance of ventricular arrhythmias in 78 female patients with Takayasu arteritis by 24-h ambulatory electrocardiography monitoring. Fifty (64%) of 78 patients had no or less than 30 beats/h premature ventricular contractions (Group A). The remaining 28 (36%) patients exhibited frequent or complex premature ventricular contractions (Group B). The frequency of HLA Bw52 which is closely associated with this morbid condition, echocardiographic and thallium-201 stress myocardial scintigraphic findings were then compared between these two groups. The frequency of positive HLA Bw52 was not significantly different between these two groups. Echocardiographically determined left ventricular mass (309 +/- 94 vs. 166 +/- 64 g; P < 0.01), frequency of complicated aortic regurgitation (77% vs. 24%; P < 0.01) and abnormal thallium-201 scintigraphic findings (76% vs. 38%; P < 0.05) were found higher in Group B as compared with those in Group A. These data indicate that frequent or complex ventricular arrhythmias in patients with Takayasu arteritis were associated with the presence of left ventricular hypertrophy, aortic regurgitation and decreased coronary reserve.

Gaucher's disease with mitral and aortic involvement: echocardiographic findings

Cardiac involvement in Gaucher's disease has been reported in only a few patients, mostly adults with pericardial changes. We describe findings in two siblings with Gaucher's disease, aged 15 and 9 years respectively, in whom mitral and aortic valve lesions were evaluated by auscultation and echocardiography. In both cases the mitral and aortic valves were thick and restricted in motion. Continuous Doppler echocardiography revealed significant mitral regurgitation and mitral stenosis. At the aortic valve level there was a systolic pressure gradient. Echocardiographic investigation of patients with suspected cardiac involvement with Gaucher's disease is recommended.

[Marfan syndrome and pregnancy, complicated by dissecting aneurysm]

Pregnant women with a Marfan syndrome carry a risk of developing an aortic arc dissection. As the developing aneurism may be diagnosed by echocardiography, this method should be applied repeatedly during pregnancy. We report the case of a Marfan patient, who developed an acute aortic dissection during the third trimester of her pregnancy and discuss the guidance and surveillance of Marfan patients who are or wish to become pregnant.

Aortic valve replacement in osteogenesis imperfecta tarda--a case report

A case of osteogenesis imperfecta tarda presenting with infective endocarditis and heart failure is discussed. Urgent aortic valve replacement was performed but the patient succumbed from pneumonia. The rarity of this disorder and the special problems encountered surgically in these patients are briefly discussed.

HLA-B27: an important genetic risk factor for lone aortic regurgitation and severe conduction system abnormalities

PURPOSE

HLA-B27, an immunogenetic marker that is present in 8 percent of the white population around the world, has been found to be an important risk factor for the development of a group of rheumatic disorders, the seronegative spondyloarthropathies. Our objective was to assess the possible role of HLA-B27 and the associated inflammatory disease process in the development of lone aortic regurgitation.

PATIENTS AND METHODS

A group of 91 patients with lone aortic regurgitation were studied by HLA typing and clinical and roentgenologic examination.

RESULTS

The HLA-B27-associated inflammatory disease process was found to be the probable underlying cause in 15 to 20 percent of patients with lone aortic regurgitation of different degrees of severity. Furthermore, HLA-B27 was found in 88 percent of the male patients with the combination of aortic regurgitation and severe conduction system abnormalities.

CONCLUSION

We suggest that this cardiac syndrome should be regarded as an HLA-B27-associated syndrome, sometimes part of ankylosing spondylitis or Reiter's disease, but just as often presenting without obvious rheumatic disease. The marker is thus an important and widely distributed risk factor not only for the development of rheumatic disease but also for acquired aortic regurgitation and sever conduction system abnormalities.

HLA and clinical manifestations in Takayasu disease

In previous studies on HLA antigens in patients with Takayasu disease, we found a statistically high frequency of haplotype Bw52-Dw12. Clinico-pathological conditions of this disease observed for 85 +/- 3 months were compared between 29 patients with (positive group) and 39 patients without this haplotype (negative group), among 82 patients with Takayasu disease. Blood sedimentation rate and C-reactive protein exhibited statistically significant high figures in the positive group as compared with those in negative group, while no difference were seen in rheumatoid arthritis test, antistreptolysin-0 titer, anti-DNA antibody, levels of circulating immune complexes, platelet aggregation, although all revealed high levels in the positive group. Pulmonary disorders were more frequent in positive group. Fourteen patients (48%) in the positive group and 5 (13%) in the negative group had abnormalities in the aortic valve (p less than 0.01). In 14 patients in the positive (38%) and 5 in the negative (13%) groups, the systolic blood pressure was over 140 mmHg (p less than 0.01). Four patients in the positive (17%) and one in the negative groups (3%) were blind (p less than 0.01). These data suggest that in patients with a haplotype of Bw52-Dw12, there is a greater likelihood of an active inflammatory state and a rapid progression of these morbid conditions.

Formes frustes of Marfan's syndrome presenting with severe aortic regurgitation. Clinicogenetic study of 18 families

Eighteen patients who presented with severe aortic regurgitation and dilatation of the ascending aorta were found to be formes frustes of Marfan's syndrome and formed the basis for this clinicogenetic study. All had aortic valve replacement and reconstruction of part of the ascending aorta. The diagnosis was confirmed by histological examination of the aortic tissue. There were 126 first degree relatives; 85 were living and 67 (78-8%) of these were examined. Limited information was available about 32 of the 41 relatives who had died. No relative had the classical clinical features of Marfan's syndrome but stigmata of the disease were found in 25 (37-3%) of the 67 first degree relatives examined. In 21, the abnormality was confined to the cardiovascular system, the skeleton, or the eye, but in 4, abnormalities involved 2 systems. Cardiovascular abnormalities affecting the aortic valve or aortic wall were present in 6 (9-0%) of the 67 first degree relatives examined. One or more of the skeletal indices measured (height-span difference, metacarpal index, phalangeal index) was abnormal in 18 (26-9%) and ocular abnormalities were found in 5 of 51 (9-8%) examined. There were no relatives with dislocation of the lens or iridodonesis. Using strict diagnostic criteria, a minimum of 37-3 per cent of the first degree relatives examined were affected; this involved 12 of the 18 families studied. There was nothing in our data to suggest that the formes frustes of the disease had a different mode of inheritance from the classical syndrome.