Periderm prevents pathological epithelial adhesions during embryogenesis.

Appropriate development of stratified, squamous, keratinizing epithelia, such as the epidermis and oral epithelia, generates an outer protective permeability barrier that prevents water loss, entry of toxins, and microbial invasion. During embryogenesis, the immature ectoderm initially consists of a single layer of undifferentiated, cuboidal epithelial cells that stratifies to produce an outer layer of flattened periderm cells of unknown function. Here, we determined that periderm cells form in a distinct pattern early in embryogenesis, exhibit highly polarized expression of adhesion complexes, and are shed from the outer surface of the embryo late in development. Mice carrying loss-of-function mutations in the genes encoding IFN regulatory factor 6 (IRF6), IκB kinase-α (IKKα), and stratifin (SFN) exhibit abnormal epidermal development, and we determined that mutant animals exhibit dysfunctional periderm formation, resulting in abnormal intracellular adhesions. Furthermore, tissue from a fetus with cocoon syndrome, a lethal disorder that results from a nonsense mutation in IKKA, revealed an absence of periderm. Together, these data indicate that periderm plays a transient but fundamental role during embryogenesis by acting as a protective barrier that prevents pathological adhesion between immature, adhesion-competent epithelia. Furthermore, this study suggests that failure of periderm formation underlies a series of devastating birth defects, including popliteal pterygium syndrome, cocoon syndrome, and Bartsocas-Papas syndrome.

A balanced translocation truncates Neurotrimin in a family with intracranial and thoracic aortic aneurysm.

BACKGROUND: Balanced chromosomal rearrangements occasionally have strong phenotypic effects, which may be useful in understanding pathobiology. However, conventional strategies for characterising breakpoints are laborious and inaccurate. We present here a proband with a thoracic aortic aneurysm (TAA) and a balanced translocation t(10;11) (q23.2;q24.2). Our purpose was to sequence the chromosomal breaks in this family to reveal a novel candidate gene for aneurysm. METHODS AND RESULTS: Intracranial aneurysm (IA) and TAAs appear to run in the family in an autosomal dominant manner: After exploring the family history, we observed that the proband's two siblings both died from cerebral haemorrhage, and the proband's parent and parent's sibling died from aortic rupture. After application of a genome-wide paired-end DNA sequencing method for breakpoint mapping, we demonstrate that this translocation breaks intron 1 of a splicing isoform of Neurotrimin at 11q25 in a previously implicated candidate region for IAs and AAs (OMIM 612161). CONCLUSIONS: Our results demonstrate the feasibility of genome-wide paired-end sequencing for the characterisation of balanced rearrangements and identification of candidate genes in patients with potentially disease-associated chromosome rearrangements. The family samples were gathered as a part of our recently launched National Registry of Reciprocal Balanced Translocations and Inversions in Finland (n=2575), and we believe that such a registry will be a powerful resource for the localisation of chromosomal aberrations, which can bring insight into the aetiology of related phenotypes.

Mutant CHUK and severe fetal encasement malformation.

We report an autosomal recessive lethal syndrome characterized by multiple fetal malformations, the most obvious anomalies being the defective face and seemingly absent limbs, which are bound to the trunk and encased under the skin. We identified the molecular defect that causes this syndrome, using a combined strategy of gene-expression arrays, candidate-gene analysis, clinical studies, and genealogic investigations. A point mutation in two affected fetuses led to the loss of the conserved helix­loop­helix ubiquitous kinase (CHUK), also known as IκB kinase α. CHUK has an essential role in the development of skin epidermis and its derivatives, along with various other morphogenetic events. (Funded by the Academy of Finland and others.).

Mutation spectrum of Meckel syndrome genes: one group of syndromes or several distinct groups?

Meckel syndrome (MKS) is a lethal malformation syndrome that belongs to the group of disorders that are associated with primary cilia dysfunction. Total of five genes are known to be involved in the molecular background of MKS. Here we have systematically analyzed all these genes in a total of 29 MKS families. Seven of the families were Finnish and the rest originated from elsewhere in Europe. We found 12 novel mutations in 13 families. Mutations in the MKS genes are also found in other syndromes and it seems reasonable to assume that there is a correlation between the syndromes and the mutations. To obtain some supportive information, we collected all the previously published mutations in the genes to see whether the different syndromes are dictated by the nature of the mutations. Based on this study, mutations play a role in the clinical phenotype, given that the same allelic combination of mutations has never been reported in two clinically distinct syndromes.

Unraveling the disease pathogenesis behind lethal hydrolethalus syndrome revealed multiple changes in molecular and cellular level.

BACKGROUND: Hydrolethalus syndrome (HLS) is a severe fetal malformation syndrome characterized by multiple developmental anomalies, including central nervous system (CNS) malformation such as hydrocephaly and absent midline structures of the brain, micrognathia, defective lobation of the lungs and polydactyly. Microscopically, immature cerebral cortex, abnormalities in radial glial cells and hypothalamic hamartoma are among key findings in the CNS of HLS fetuses. HLS is caused by a substitution of aspartic acid by glycine in the HYLS1 protein, whose function was previously unknown. RESULTS: To provide insight into the disease mechanism(s) of this lethal disorder we have studied different aspects of HLS and HYLS1. A genome-wide gene expression analysis indicated several upregulated genes in cell cycle regulatory cascades and in specific signal transduction pathways while many downregulated genes were associated with lipid metabolism. These changes were supported by findings in functional cell biology studies, which revealed an increased cell cycle rate and a decreased amount of apoptosis in HLS neuronal progenitor cells. Also, changes in lipid metabolism gene expression were reflected by a significant increase in the cholesterol levels of HLS liver tissues. In addition, based on our functional studies of HYLS1, we propose that HYLS1 is a transcriptional regulator that shuffles between the cytoplasm and the nucleus, and that when HYLS1 is mutated its function is significantly altered. CONCLUSION: In this study, we have shown that the HYLS1 mutation has significant consequences in the cellular and tissue levels in HLS fetuses. Based on these results, it can be suggested that HYLS1 is part of the cellular transcriptional regulatory machinery and that the genetic defect has a widespread effect during embryonic and fetal development. These findings add a significant amount of new information to the pathogenesis of HLS and strongly suggest an essential role for HYLS1 in normal fetal development.

Hydrolethalus syndrome: neuropathology of 21 cases confirmed by HYLS1 gene mutation analysis.

Hydrolethalus syndrome is a lethal malformation syndrome with a severe brain malformation, most often hydrocephaly and absent midline structures. Other frequent findings are micrognathia, polydactyly, and defective lobation of the lungs. Hydrolethalus syndrome is inherited in an autosomal recessive manner and is caused by a missense mutation in the HYLS1 gene. Here, we report the neuropathologic features of 21 genetically confirmed cases. Typically, 2 separated cerebral hemispheres could be identified, but they lacked midline and olfactory structures and were situated basally with a massive accumulation of cerebrospinal fluid. Temporal and occipital lobes were hypoplastic, and normally developed hippocampi were not found. Primitive thalami and basal ganglia were fused in the midline. A hypothalamic hamartoma was a frequent finding, and brainstem and cerebellum were hypoplastic. Three cases were hydranencephalic, and 1 was anencephalic. A midline "keyhole" defect in the skull base was a constant finding. Histologically, the cortex was dysplastic. This pattern of brain pathology, clearly belonging to the midline patterning defects, seems to be unique for the hydrolethalus syndrome and combines features of disturbed neurulation, prosencephalization, and migration. Despite variation in the clinicopathologic phenotype, all cases in the series carried the same homozygous missense mutation in HYLS1.

Identification of CC2D2A as a Meckel syndrome gene adds an important piece to the ciliopathy puzzle.

Meckel syndrome (MKS) is a lethal malformation disorder characterized classically by encephalocele, polycystic kidneys, and polydactyly. MKS is also one of the major contributors to syndromic neural tube defects (NTDs). Recent findings have shown primary cilia dysfunction in the molecular background of MKS, indicating that cilia are critical for early human development. However, even though four genes behind MKS have been identified to date, they elucidate only a minor proportion of the MKS cases. In this study, instead of traditional linkage analysis, we selected 10 nonrelated affected fetuses and looked for the homozygous regions shared by them. Based on this strategy, we identified the sixth locus and the fifth gene, CC2D2A (MKS6), behind MKS. The biological function of CC2D2A is uncharacterized, but the corresponding polypeptide is predicted to be involved in ciliary functions and it has a calcium binding domain (C2). Immunofluorescence staining of patient's fibroblast cells demonstrates that the cells lack cilia, providing evidence for the critical role of CC2D2A in cilia formation. Our finding is very significant not only to understand the molecular background of MKS, but also to obtain additional information about the function of the cilia, which can help to understand their significance in normal development and also in other ciliopathies, which are an increasing group of disorders with overlapping phenotypes.

Apolipoprotein E polymorphism is associated with both carotid and coronary atherosclerosis in patients with coronary artery disease.

BACKGROUND AND AIMS: Apolipoprotein E (apoE) polymorphism plays a significant role in the development of atherosclerosis and cardiovascular disease. Therefore, the aim of the present study was to examine the association between apoE polymorphism and carotid intima-media thickness (IMT), and severity and extent of coronary artery disease (CAD). METHODS AND RESULTS: B-mode ultrasound and quantitative coronary angiography (QCA) were used to assess carotid, and coronary artery atherosclerosis in 91 patients with clinically suspected CAD referred for cardiac catheterization. Two apoE phenotype groups were defined: apoE3 (E3/E3) and apoE4 (including E4/E3, E4/E4 phenotypes). Maximum IMT was higher in the apoE4 group than in the apoE3 group (p=0.022). The global atheroma burden index was similarly higher in the apoE4 group than in the apoE3 group (p=0.033). ApoE4 subjects had higher levels of apolipoprotein B (apoB) (p=0.008), triglycerides (p=0.006), remnant lipoprotein-cholesterol (RLP-C) (p=0.023), and lipoprotein(a) [(Lp(a)] (p=0.041) than apoE3 subjects. The mean LDL particle size was smaller in the apoE4 group than in the apoE3 group (p=0.041). CONCLUSIONS: ApoE polymorphism was associated with both carotid and coronary atherosclerosis. Patients with the apoE4 isoform had an increased carotid IMT and a more severe and extensive CAD than patients with the apoE3 isoform.

Augmentation index and carotid intima-media thickness are differently related to age, C-reactive protein and oxidized low-density lipoprotein.

OBJECTIVE: Ageing, plasma circulating C-reactive protein (CRP), oxidized low-density lipoprotein (OxLDL) and homocysteine (Hcy) are associated with atherosclerosis. The aim of this study was to evaluate the relationship between age, inflammatory and oxidative stress-related markers with functional and structural changes of the arteries in asymptomatic persons. METHODS: CRP, OxLDL and Hcy were measured in 175 clinically healthy subjects, aged 40-70 years. Ultrasonography and pulse wave analysis were used to measure carotid intima-media thickness (IMT) and augmentation index (AIx). RESULTS: OxLDL was correlated with IMT (r = 0.24, P = 0.003), whereas CRP was correlated with AIx (r = 0.21, P = 0.005). No correlation was detected between Hcy and AIx or age-adjusted IMT. There was a significant association between AIx and age 50 years (r = 0.40; P = 0.001). In stepwise regression analysis age, weight, white blood cell count, OxLDL, heart rate and timing of the reflected waveform adjusted for height were significantly and independently associated with IMT (R = 0.41; P < 0.001). At the same time, AIx as the dependent variable correlated positively with age, gender, CRP and mean arterial pressure, and negatively with heart rate, weight and height, in stepwise regression analysis (R = 0.63; P < 0.001). CONCLUSION: The results of the present study showed that CRP, OxLDL, Hcy and age are not similarly related to AIx and IMT in asymptomatic persons. The results suggest that CRP and younger age are related to arterial stiffness, whereas OxLDL and older age become more important determinants of structural changes of the arteries in asymptomatic persons.

Association of carotid intima-media thickness with angiographic severity and extent of coronary artery disease.

The present study examined the association between carotid intima-media thickness (IMT) and severity and extent of coronary artery disease (CAD). B-mode ultrasound and quantitative coronary angiography were used to assess carotid and coronary artery atherosclerosis in 108 patients with known or suspected CAD who had been referred for cardiac catheterization. Maximum and mean IMT values of carotid arteries were measured and expressed as mean aggregate values. To evaluate anatomic severity and extent of CAD, several quantitative coronary angiographically derived parameters were incorporated into indexes. These quantitative coronary angiographic measurements reflected CAD severity, extent, and overall "atheroma burden" and were calculated for the entire coronary tree and separately for different coronary segments (i.e., left main, proximal, mid, and distal segments). Maximum and mean IMT values were significantly correlated with CAD severity (p = 0.004 and 0.005, respectively), extent (p = 0.022 and 0.016, respectively), and atheroma burden (p = 0.008 for the 2 values). Further, carotid IMT was correlated with quantitative angiographic indexes for mid and distal segments but not with the proximal segments of coronary vessels. In conclusion, our study shows an association between carotid IMT and severity and extent of CAD as assessed by quantitative coronary angiography. Carotid IMT seems to be a weaker predictor of coronary atherosclerosis in the proximal parts of the coronary tree than in the mid and distal parts.

Decreased high-density lipoprotein (HDL) particle size, prebeta-, and large HDL subspecies concentration in Finnish low-HDL families: relationship with intima-media thickness.

OBJECTIVE: High-density lipoprotein (HDL) cholesterol correlates inversely with the risk of coronary heart disease (CHD). The precise antiatherogenic mechanisms of HDL subspecies are not thoroughly elucidated. We studied the relationship between carotid intima-media thickness (IMT) and HDL subspecies distribution in Finnish families with low HDL cholesterol and premature CHD. METHODS AND RESULTS: Altogether, 148 members of Finnish low-HDL families and 133 healthy control subjects participated in our study. HDL particle size was significantly smaller in affected family members (HDL < or =10th Finnish age-sex specific percentile) compared with unaffected family members and control subjects (9.1+/-0.04 nm versus 9.5+/-0.05 nm, P<0.0001, versus 9.8+/-0.03 nm, P<0.0001 [mean+/-SE]). Large HDL2b particles as well as prebeta-HDL concentration were significantly decreased among the affected family members. Mean IMT was significantly higher in the affected family members than in the control subjects (0.85+/-0.01 mm versus 0.79+/-0.01 mm; P<0.0001). Age, HDL2b, systolic blood pressure, and prebeta-HDL were significant independent determinants of mean IMT. CONCLUSIONS: The decreased levels of HDL2b and prebeta-HDL reflect the potentially efflux-deficient HDL subspecies profile in the affected low-HDL family members. Decreased HDL particle size caused by the decrease of plasma concentration of HDL2b and decreased prebeta-HDL levels correlate with increased IMT.

MKS1, encoding a component of the flagellar apparatus basal body proteome, is mutated in Meckel syndrome.

Meckel syndrome (MKS) is a severe fetal developmental disorder reported in most populations. The clinical hallmarks are occipital meningoencephalocele, cystic kidney dysplasia, fibrotic changes of the liver and polydactyly. Here we report the identification of a gene, MKS1, mutated in MKS families linked to 17q. Mks1 expression in mouse embryos, as determined by in situ hybridization, agrees well with the tissue phenotype of MKS. Comparative genomics and proteomics data implicate MKS1 in ciliary functions.

Polyphenol-rich phloem enhances the resistance of total serum lipids to oxidation in men.

In humans, polyphenol supplementation studies have resulted in inconsistent findings in lipid peroxidation. Our aim was to investigate the effects of a 4-week consumption of polyphenol-rich phloem on serum lipids and lipid peroxidation in the hydrophilic fraction of serum and on isolated lipoproteins. We conducted a randomized double-blind supplementation study consisting of 75 nonsmoking hypercholesterolemic men. Participants consumed 70 g daily of either rye bread (placebo) or phloem-fortified rye bread containing 31 mg (low polyphenol, LP) or 62 mg (high polyphenol, HP) of catechins. The ex vivo susceptibility of total serum lipids and VLDL and LDL to oxidation after copper induction was measured as a lag time to the maximal oxidation rate at the baseline and after the supplementation. In the HP group, an increase in the oxidation resistance of total serum lipids was observed (11.4%), while no effect was seen in the LP group (-0.8%) or in the placebo group (-1.0%) (p = 0.007). No differences were observed in the oxidation resistance of VLDL and LDL between the study groups. The phloem also increased in vitro oxidation resistance of serum lipids and radical scavenging activity (DPPH.) in a dose-dependent manner. Our results suggest that polyphenols may inhibit lipid peroxidation in the hydrophilic fraction of serum.

Hydrolethalus syndrome is caused by a missense mutation in a novel gene HYLS1.

Hydrolethalus syndrome (HLS) is an autosomal recessive lethal malformation syndrome characterized by multiple developmental defects of fetus. We have earlier mapped and restricted the HLS region to a critical 1 cM interval on 11q23-25. The linkage disequilibrium (LD) and haplotype analyses of single nucleotide polymorphism (SNP) markers helped to further restrict the HLS locus to 476 kb between genes PKNOX2 and DDX25. An HLS associated mutation was identified in a novel regional transcript (GenBank accession no. FLJ32915), referred to here as the HYLS1 gene. The identified A to G transition results in a D211G change in the 299 amino acid polypeptide with unknown function. The HYLS1 gene shows alternative splicing and the transcript is found in multiple tissues during fetal development. In situ hybridization shows spatial and temporal distributions of transcripts in good agreement with the tissue phenotype of HLS patients. Immunostaining of in vitro expressed polypeptides from wild-type (WT) cDNA revealed cytoplasmic staining, whereas mutant polypeptides became localized in distinct nuclear structures, implying a disturbed cellular localization of the mutant protein. The Drosophila melanogaster model confirmed these findings and provides evidence for the significance of the mutation both in vitro and in vivo.

Serum antibody levels to Actinobacillus actinomycetemcomitans predict the risk for coronary heart disease.

OBJECTIVE: The association between serum antibody levels to major periodontal pathogens and coronary heart disease (CHD) was analyzed in a prospective population-based study. METHODS AND RESULTS: The population comprised 1023 men (aged 46 to 64 years) in the Kuopio Ischemic Heart Disease Study. The subjects with CHD at baseline (n=113) were more often seropositive for Porphyromonas gingivalis IgA (38.9% versus 28.5%, P=0.021) and IgG (60.2% versus 46.7%, P=0.007) than those without CHD. During the 10-year follow-up, 109 men free from CHD at baseline experienced an acute myocardial infarction or CHD death. The men with an end point were more often seropositive for Actinobacillus actinomycetemcomitans IgA (15.5% versus 10.2%, P=0.019) than those who remained healthy. In the highest tertile of A. actinomycetemcomitans IgA-antibodies compared with the lowest one, the relative risk (RR) for an end point adjusted for CHD risk factors was 2.0 (95% confidence interval [CI], 1.2 to 3.3). In the Porphyromonas gingivalis IgA-antibody tertiles, the highest RR of 2.1 (1.3 to 3.4) was observed in the second tertile. All antibody levels correlated positively with the carotid artery intima-media thickness. CONCLUSIONS: High-serum antibody levels to major periodontal pathogens are associated with subclinical, prevalent, and future incidence of CHD. Periodontal pathogens or host response against them may contribute to the pathogenesis of CHD.

The effects of coffee consumption on lipid peroxidation and plasma total homocysteine concentrations: a clinical trial.

Despite extensive research, the cardiovascular effects of coffee consumption in humans remain controversial. Our aim was to investigate the excretion of coffee phenols and the effects of filtered coffee consumption on oxidative stress and plasma homocysteine (tHcy) concentration in humans. The study consisted of a multiple-dose clinical supplementation trial and a single-dose study. In the long-term trial, 43 healthy nonsmoking men optionally consumed daily either no coffee, 3 cups (450 mL), or 6 cups (900 mL) of filtered coffee for 3 weeks, while in the short-term study 35 subjects consumed a single dose of 0, 1 (150 mL), or 2 cups (300 mL) of coffee. Long-term consumption of coffee increased the urinary excretion of caffeic and ferulic acid. The change in the total excretion of phenolic acids in 3 and 6 cups groups represented 3.8 and 2.5% of the amount ingested daily. Plasma tHcy concentrations increased nonsignificantly, but the consumption of coffee had neither short-nor long-term effects on lipid peroxidation or the activity of measured antioxidant enzymes. In conclusion, the consumption of filtered coffee does not have any detectable effects on lipid peroxidation in healthy nonsmoking men. The effect of coffee consumption on tHcy concentrations needs further investigation.

Systolic blood pressure during recovery from exercise and the risk of acute myocardial infarction in middle-aged men.

We prospectively assessed the association of systolic blood pressure (SBP) after exercise with the risk of an acute myocardial infarction. Limited information exists currently on the role of SBP during recovery period with the risk of acute myocardial infarction. SBP was measured every 2 minutes during and after a progressive cycle ergometer exercise test in a representative sample of 2336 men (aged 42 to 61 years). During an average follow-up period of 13.1 years, 358 acute myocardial infarctions occurred. An incremental rise of 10 mm Hg per minute in SBP at 2 minutes after exercise (relative risk, 1.07-fold; 95% confidence interval [CI], 1.03 to 1.12; P=0.001) was associated with the risk of acute myocardial infarction after adjustment for age, alcohol consumption, smoking, serum lipids, diabetes mellitus, body mass index, resting SBP, regular use of antihypertensive medications, physical fitness, heart rate, and ischemic ECG findings during exercise. Men with elevated SBP of >195 mm Hg after exercise had a 1.69-fold (95% CI, 1.24 to 2.30; P=0.001) risk for an acute myocardial infarction compared with those with SBP <170 mm Hg after adjustment for age, other risk factors, and resting SBP. SBP after exercise provides an incremental predictive value for acute myocardial infarction beyond that of resting SBP. This emphasizes the importance of SBP measurements after the exercise test because it provides additional valuable prognostic measure with regard to acute myocardial infarction.

Two-stage ultrasonography in screening for fetal anomalies at 13-14 and 18-22 weeks of gestation.

BACKGROUND: The aim of this study was to assess the value of two-stage screening by ultrasonography in detecting selected major fetal anomalies in a low-risk obstetric population. METHODS: In a defined geographic area, 4789 consecutive low-risk pregnant women participated in screening by two-stage ultrasonography as part of routine maternal care. The examinations were usually performed by specially trained midwives at 13-14 and 18-22 weeks of gestation. Of the women, 4073 had both scans, 440 had the early one only, and 276 the late scan only. Pregnancy outcomes were ascertained from obstetric and pediatric records, and the data were supplemented with information from the national birth and malformation registries. RESULTS: Of the 4855 fetuses, 33 (0.7%) had major structural defects considered detectable by ultrasonography. Of these, six (18%) were identified at the early scan, and an additional 10 (30%) at the late scan, yielding a total sensitivity of 48% for the two-stage screening. Twenty offspring had chromosomal abnormalities; 10 were identified by increased nuchal translucency at the early scan, one additional one (by hydronephrosis) at the late scan, and the remaining nine at birth. CONCLUSIONS: In a low-risk population, first-trimester scanning is useful in finding fetuses with chromosomal anomalies, but a second-trimester scan is needed for other types of defects. The sensitivity of routine screening by midwives for fetal structural defects in a general obstetric population remains lower than that reported by specialized centers.

Inflammation, abdominal obesity, and smoking as predictors of hypertension.

Development of hypertension has been linked to chronic low-grade inflammation. However, it is not known whether this connection is mediated by features of the metabolic syndrome or smoking, or their changes, which themselves have been linked to inflammation. We studied the predictive value of highly sensitive C-reactive protein (hs-CRP), smoking, and abdominal obesity to the development of hypertension in an 11-year follow-up of a population-based study cohort comprising 379 middle-aged normotensive men. During the follow-up, 124 men (33%) developed hypertension. Men with hs-CRP > or =3.0 mg/L were 2.8x (95% confidence interval, 1.2 to 6.6) more likely to develop hypertension than with hs-CRP <1.0 mg/L even after adjustment for features of the metabolic syndrome, lifestyle factors, and their changes. Cigarette smoking was also associated with development of hypertension independently of inflammation and other confounders. Waist girth increased more in men who quit smoking than in other men. An increase in waist girth during follow-up strongly predicted incident hypertension. The decrease in smoking was not associated with a lower risk of hypertension in age-adjusted analyses. Hypertension is preceded by low-grade chronic inflammation in middle-aged white men independently of smoking or features of the metabolic syndrome. Furthermore, smoking may be a risk factor for hypertension. Although stopping smoking is beneficial with respect to health outcomes, the subsequent increase in weight and waist girth associated with smoking cessation may offset the decrease in the risk of hypertension that one may otherwise expect.