Mutations in FKBP10 cause recessive osteogenesis imperfecta and Bruck syndrome.

Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue characterized by bone fragility and alteration in synthesis and posttranslational modification of type I collagen. Autosomal dominant OI is caused by mutations in the genes (COL1A1 or COL1A2) encoding the chains of type I collagen. Bruck syndrome is a recessive disorder featuring congenital contractures in addition to bone fragility; Bruck syndrome type 2 is caused by mutations in PLOD2 encoding collagen lysyl hydroxylase, whereas Bruck syndrome type 1 has been mapped to chromosome 17, with evidence suggesting region 17p12, but the gene has remained elusive so far. Recently, the molecular spectrum of OI has been expanded with the description of the basis of a unique posttranslational modification of type I procollagen, that is, 3-prolyl-hydroxylation. Three proteins, cartilage-associated protein (CRTAP), prolyl-3-hydroxylase-1 (P3H1, encoded by the LEPRE1 gene), and the prolyl cis-trans isomerase cyclophilin-B (PPIB), form a complex that is required for fibrillar collagen 3-prolyl-hydroxylation, and mutations in each gene have been shown to cause recessive forms of OI. Since then, an additional putative collagen chaperone complex, composed of FKBP10 (also known as FKBP65) and SERPINH1 (also known as HSP47), also has been shown to be mutated in recessive OI. Here we describe five families with OI-like bone fragility in association with congenital contractures who all had FKBP10 mutations. Therefore, we conclude that FKBP10 mutations are a cause of recessive osteogenesis imperfecta and Bruck syndrome, possibly Bruck syndrome Type 1 since the location on chromosome 17 has not been definitely localized.

Sevelamer hydrochloride: A novel treatment of hyperphosphatemia associated with tumor lysis syndrome in children

Background. Sevelamer is a phosphate-binder used effectively for the treatment of hyperphosphatemia in patients treated with dialysis. Objectives. To describe the safety of sevelamer in children with hyperphosphatemia secondary to tumor lysis syndrome and the serum phosphate concentrations observed following its administration. Procedure. A retrospective chart review of all children with leukemia/lymphoma diagnosed between November 2002 and April 2004 who received sevelamer during their initial admission was conducted. We monitored the effects of sevelamer on serum phosphate concentration, calcium/phosphate product and renal function at hours 24, 48, and 72 from sevelamer initiation. Results. Thirteen patients received sevelamer during the Study period. Their median age was 13 years (range 2.7-17.9) and eight were boys. Nine children had acute lymphoblastic leukemia, one had acute myeloid leukemia and 3 had non-Hodgkin's lymphoma. The most frequently used dose of sevelamer was 400 mg orally twice daily. The median duration of sevelamer therapy was 2 days (range 1 -7). Two children were excluded from the efficacy analysis due to concurrent use of dialysis. Mean serum phosphate levels decreased after sevelamer administration, in eleven patients, from a baseline 2.2 mmol/L +/- 0.4 (95% Cl, 1.7-3.1) to 1.1 mmol/L +/- 0.2 at hour 72 (95%Cl, 0.6-1.5). The only toxicity attributed to sevelamer was mild vomiting in three patients. Conclusions. Sevelamer appears to be effective and tolerable for the treatment of hyperphosphatemia associated with tumor lysis syndrome.

Regulation of the cardiac voltage-gated sodium channel Nav1.5 : regulation of Nav1.5 by ubiquitin-protein ligases of the Nedd4/Nedd4-like family and characterisation of two novel mutations in the gene encoding Nav1.5 (SCN5A) implicated in the Brugada syndrome triggered by fever

Abstract: The genesis of the cardiac action potential, which accounts for the cardiac contraction, is due to the sodium current INa mediated by the voltage-gated sodium channel Nav1.5. Several cardiac arrhythmias such as the Brugada syndrome are known te be caused by mutations in SCN5A, the gene encoding Nav1.5. Studies of these mutations allowed a better understanding of biophysical and functional properties of Nav1.5. However, only few investigations have been performed in order to understand the regulation of Nav1.5. During my thesis, I investigated different mechanisms of regulation of Nav1.5 using a heterologous expression system, HEK293 cells, coupled with a technique of sodium current recording: the patch clamp in whole cell configuration. In previous studies it has been shown that an enzyme of the Nedd4 family (Nedd4-2) regulates an epithelial sodium channel via the interaction with PY-motifs present in the latter. Interestingly, Nav1.5 contains a similar PY-motif, which motivated us to study the role of Nedd4-2 expressed in heart for the regulation of Nav1.5. In a second study, we investigated the implication of two Nav1.5 mutants, which were either less functional or net functional (Nav1.5 R535X and Nav1.5 L325R respectively) implied in the genesis of the Brugada syndrome by fever. Our results established two mechanisms implied in Nav1.5 regulation. The first one implies that following the interaction between the PY-motif of Nav1.5 and Nedd4- 2 Nav1.5 is ubiquitinated by Nedd4-2. This ubiquitination leads to the internalization of Nav1 .5. The second mechanism is a phenomenon called the "dominant negative" effect of Nav1.5 L325R on Nay1.5 where the decrease of 'Na is potentially due to the retention of Nav1.5 by Nav1.5 L325R in an undefined intracellular compartment. These studies defined two mechanisms of Nav1.5 regulation, which could play an important role for the genesis of cardiac arrhythmias where molecular processes are still poorly understood. Résumé La genèse du potentiel d'action cardiaque, permettant la contraction cardiaque, est due au courant sodique INa issu des canaux sodiques cardiaques dépendants du voltage Nav1.5. Nombreuses arythmies cardiaques telles que le syndrome de Brugada sont connues pour être liées à des mutations du gène SCN5A, codant pour Nav1.5. L'étude de ces mutations a permis une meilleure compréhension des propriétés structurelles et fonctionnelles de Nav1.5 et leurs implications dans la genèse de ces pathologies. Néanmoins peu d'études ont été menées afin de comprendre les mécanismes de régulation de Nav1.5. Mon travail de thèse a consisté à étudier des mécanismes de régulation de Nav1.5 en utilisant un système d'expression hétérologue, les cellules HEK293, couplé à une technique d'enregistrement des courants sodiques, le "patch clamp" en configuration cellule entière. La présence sur Nav1.5 d'un motif-PY similaire à ceux nécessaires pour la régulation d'un canal épithélial sodique par une enzyme de la famille de Nedd4, nous a amenée à étudier le rôle de ces ubiquitine-ligases, en particulier Nedd4-2, dans la régulation de Nav1.5. La seconde étude s'est intéressée aux conséquences de deux mutations de SCN5A codant pour deux mutants peu ou pas fonctionnels (Nav1.5 L325R et Nav1.5 R535X respectivement) retrouvées chez des patients présentant un syndrome de Brugada exacerbé par un état fébrile. Nos résultats ont permis d'établir deux mécanismes de régulation de Nav1.5 L'un par Nedd4-2 qui implique rubiquitination de Nav1.5 par cette ligase suite à l'interaction entre le motif-PY de Nav1.5 et Nedd4-2. Cette modification déclenche l'internalisation du canal impliquée dans la diminution d'INa. Le second mécanisme quant à lui est un effet "dominant négatif" de Nav1.5 L325R sur Nav1.5 aboutissant à une diminution d'INa suite à la séquestration intracellulaire potentielle de Nav1.5 par Nav1.5 L325R. Ces études ont mis en évidence deux mécanismes de régulation de Nav1.5 pouvant jouer un rôle majeur dans la genèse et/ou l'accentuation des arythmies cardiaques dont les processus moléculaires au sein des cardiomyocytes, impliquant des modifications du courant sodiques, sont encore mal compris. Résumé destiné à un large public La dépolarisation électrique de la membrane des cellules cardiaques permet la contraction du coeur. La génèse de cette activité électrique est due au courant sodique issu d'un type de canal à sodium situé dans la membrane des cellules cardiaques. De nombreuses pathologies provoquant des troubles du rythme cardiaque sont issues de mutations du gène qui code pour ce canal à sodium. Ces canaux mutants, entrainant diverses pathologies cardiaques telles que le syndrome de Brugada, ont été largement étudiées. Néanmoins, peu de travaux ont été réalisés sur les mécanismes de régulation de ce canal à sodium non muté. Mon travail de thèse a consisté à étudier certains des mécanismes de régulation de ce canal à sodium en utilisant une technique permettant l'enregistrement des courants sodiques issus de l'expression de ces canaux à sodium à la membrane de cellules mammifères. La présence sur ce canal à sodium d'une structure spécifique, similaire à celle nécessaire pour la régulation d'un canal épithélial à sodium par une enzyme appelée Nedd4-2, nous a amenée à étudier le rôle de cette enzyme dans la régulation de ce canal à sodium. La seconde étude s'est intéressée aux rôles de deux mutations du gène codant pour ce canal à sodium retrouvées chez des patients présentant un syndrome de Brugada exacerbé par la fièvre. Nos résultats nous ont permis d'établir deux mécanismes de régulation de ce canal à sodium diminuant le courant sodique l'un par l'action de l'enzyme Nedd4-2, suite à son interaction avec ce canal, qui modifie ce canal à sodium (ubiquitination) diminuant de ce fait la densité membranaire du canal. L'autre par un mécanisme suggérant un effet négatif de l'un des canaux mutants sur l'expression à la membrane du canal à sodium non muté. Ces études ont mis en évidence deux mécanismes de régulation de ce canal à sodium pouvant jouer un rôle majeur dans la genèse et/ou l'accentuation des troubles du rythme cardiaques dont les mécanismes cellulaires sont encore incompris.

Phenotypic and molecular characterization of Bruck syndrome (Osteogenesis imperfecta with contractures of the large joints) caused by a recessive mutation in PLOD2

Le Syndrome de Bruck (Bruck Syndrome; BS) est une maladie autosomique récessive assemblant la combinaison inhabituelle de fragilité osseuse semblable à celle de l'Ostéogenèse Imparfaite (0I) avec des contractures congénitales tendineuses et cutanées des grandes articulations («ptérygia»). Les cas décrits jusqu'à ce jour mettent en évidence une grande hétérogénéité du tableau clinique, liée en partie au manque d'un diagnostic biochimique ou moléculaire. Nous savons que dans le BS les gènes codant pour le collagène 1 ne sont pas mutés, mais savons néanmoins, grâce à l'étude du collagène extrait de biopsies osseuses, qu'il y a un déficit d'hydroxylation des résidus de lysine dans les télopeptides du collagène 1 qui servent à la formation des liens intermoléculaires (crosslinks) et donc à la stabilisation des fibres de collagène. Un locus génétique du BS à été mappé sur 17q12, mais le gène responsable sur ce locus reste inconnu; plus récemment, deux mutations dans le gène de la lysyl hydroxylase 2 (PLOD2, position chromosomique 3q23-q24) ont été identifiées, démontrant l'hétérogénéité génétique du ES. La proportion de ES liée à 17p22 (BS type 1) et celle liée à une mutation dans PLOD2 (BS type 2) est encore incertaine et nous manquons de données sur la corrélation phenotype-génotype. Nous avons étudié le cas d'un garçon avec des contractures et des ptérygia dès la naissance, combinées à une ostéopénie sévère de type OI menant à des fractures multiples. Ses urines contenaient une quantité élevée d'hydroxyproline, indiquant un remaniement important du tissu osseux, mais peu de produits de dégradation des crosslinks du collagène, indiquant donc une réduction de la proportion de crosslinks dans le collagène in vivo. Nous avons pu démontrer chez lui la présence d'une nouvelle mutation homozygote dans le gène PLOD2 menant à une substitution Arg598His; les deux parents du sujet étaient hétérozygotes pour la mutation et celle-ci était absente dans notre population témoin. La mutation est adjacente aux deux mutations rapportées précédemment (Gly601Val et Thr608Ile), ce qui suggère la présence d'un ''hotspot'' mutationnel mais aussi d'une région de grande importance fonctionnelle sur PLOD2 : cette observation est importante pour la création d'inhibiteurs de PLOD2, recherchés en ce moment pour le traitement de la fibrose. La combinaison de ptérygia et de fragilité osseuse, comme illustrée par notre patient est apparemment contradictoire et donc difficilement explicable mais indique que l'hydroxylation des résidus lysyl des télopeptides est importante non seulement pour la stabilité osseuse mais aussi dans la morphogénèse et la formation des articulations dans la période prénatale. Finalement, la mesure des produits de dégradation du collagène dans l'urine et l'analyse de mutation de PLOD2 permet le diagnostic du syndrome de Bruck et permet de le différencier de l'Osteogénèse Imparfaite. -- Bruck syndrome (BS) is a recessively-inherited phenotypic disorder featuring the unusual combination of skeletal changes resembling osteogenesis imperfecta (0I) with congenital contractures of the large joints. Clinical heterogeneity is apparent in cases reported thus far. While the genes coding for collagen 1 chains are unaffected in BS, there is biochemical evidence for a defect in the hydroxylation of lysine residues in collagen 1 telopeptides. One BS locus has been mapped at 17p12, but more recently, two mutations in the lysyl hydroxylase 2 gene (PLOD2, 3q23-q24) have been identified in BS, showing genetic heterogeneity. The proportion of BS cases linked to 17p22 (BS type 1) or caused by mutations in PLOD2 (BS type 2) is still uncertain, and phenotypic correlations are lacking. We report on a boy who had congenital contractures with pterygia at birth and severe 0I-like osteopenia and multiple frac-tures. His urine contained high amounts of hydroxyproline but low amounts of collagen crosslinks degradation products; and he was shown to be homozygous for a novel mutation leading to an Arg598His substitution in PLOD2. The mutation is adjacent to the two mutations previously reported (Gly601Val and Thr608Ile), suggesting a functionally important hotspot in PLOD2. The combination of pterygia with bone fragility, as illustrated by this case, is difficult to explain; it suggests that telopeptide lysyl hydroxylation must be involved in prenatal joint formation and morphogenesis. Collagen degradation products in urine and mutation analysis ofPLOD2 maybe used to diagnose BS and differentiate it from M.

The generation and analysis of combined legless 1 and 2 knock-out mice

Summary The Wnt signaling pathway plays an important role during development and also for maintaining tissue homeostasis due to its function in proliferation, differentiation and cell fate decisions. Wnt ligands bind to Frizzled receptors and activate a signaling cascade that results in the stabilization of β-Catenin, a key component of the pathway. β-Catenin translocates to the nucleus, where, together with a transcription factor of the Tcf/Lef family, it activates the expression of target genes. Legless and Pygopus are two recently discovered essential components of the Wnt pathway in Drosophila, which may mediate the nuclear import and retention of beta-Catenin and/or contribute directly to the activation of Wnt target genes. To address the function of Legless in the mouse, we have generated compound constitutive and conditional knockout alleles of the two homologues legless 'I (bc1-9) and 2. We have induced the deletion of legless in self-renewing tissues such as the gastrointestinal tract, the mammary gland and the skin during adulthood and constitutively in the embryo. The present thesis focused on the consequences of the inactivation of legless in epithelial homeostasis as well as in a regeneration model and its comparison to pygopus. Deletion of neither legless nor pygopus in the adult small intestine resulted in any apparent anomaly, contrasting expectations from the phenotype caused by over-expression of Dickkopf, a Wnt inhibitor (Pinto et al., 2003). These observations indicate that canonical Wnt signaling might not be indispensable for normal gastrointestinal epithelium homeostasis, or that, in this context, Legless and Pygopus are not essential components of the Wnt pathway. However, the regeneration of the colonic epithelium after DSS induced damage was markedly impaired in legless, but not in pygopus deficient mice. Thus, unlike in Drosophila, deletion of mammalian legless and pygopus resulted in different phenotypes, suggesting that Legless might interact with as yet unidentified partners in addition to Pygopus. Resumé La voie de signalisation Wnt joue un rôle important au cours du développement ainsi que pour le maintien de l' homéostase tissulaire due à sa fonction durant la prolifération, la différentiation et les décisions sur l'avenir des cellules. Les ligands de Wnt se lient aux récepteurs Frizzled et activent une cascade de signalisation résultant en la stabilisation de β-Catenin, un composant central de cette voie. β-Catenin est transloquée dans le noyau ou, avec l'aide des facteurs de transcription de la famille Tcf/lef, elle active la transcription des gènes cibles. Legless et Pygopus sont deux composants récemment découverts et essentiels de la voie de signalisation Wnt chez la Drosophile qui pourraient être des médiateurs de l'import et de la rétention nucléaire de bêta-catenin et/ou contribuer directement a l'activation des gènes cibles. Afin de comprendre la fonction de Legless chez la souris, nous avons généré simultanément les allèles « knock-out » constitutifs et conditionnels des deux homologues legless 1 (bc1-9) et 2. Nous avons induit la délétion de legless dans des tissus capables de s'auto renouveler comme le tract gastro-intestinal, la glande mammaire et la peau chez l'adulte et nous avons supprimé constitutivement legless chez l'embryon. La présente thèse est concentrée sur les conséquences de l'inactivation de legless au cours de l' homéostase épithéliale ainsi que dans un modèle de régénération et sur sa comparaison avec pygopus. Ni la délétion de legless ni celle de pygopus dans l'intestin adulte n'ont résulté en quelque anomalie, contrastant nos attentes provenant des phénotypes causes par la surexpression de Dickkpof, un inhibiteur de Wnt (Pinto et al., 2003). Ces observations indiquent que la voie de signalisation Wnt/β-Catenin pourrait ne pas être indispensable à l' homéostase normale du tract gastro-intestinal, ou que, dans ce contexte, Legless et Pygopus ne sont pas des composants essentiels de la vole Wnt. Cependant, la régénération de l'épithélium du colon après induction de son endommagement au DSS fut dramatiquement diminuée chez legless mais pas chez les souris mutantes pour pygopus. Ainsi, a la différence de chez la Drosophile, la délétion de legless et pygopus chez les mammifères a résulté en des phénotypes différents, suggérant que Legless pourrait interagir avec d'autres partenaires, encore non identifies, que Pygopus.

Lamotrigine can be beneficial in patients with Dravet syndrome.

Dravet syndrome, a severe infantile epilepsy syndrome, is typically resistant to anti-epileptic drugs (AED). Lamotrigine (LTG), an AED that is effective for both focal and generalized seizures, has been reported to aggravate seizures in Dravet syndrome. Therefore, LTG is usually avoided in Dravet syndrome. We describe two adults and a child with Dravet syndrome in whom LTG resulted in decreased seizure duration and frequency. This benefit was highlighted in each patient when LTG was withdrawn after 6 to 15 years, and resulted in an increased frequency of convulsive seizures together with longer seizure duration. A 25-year-old male required hospital admission for frequent seizures for the first time in 7 years, 6 weeks after ceasing LTG. Reintroduction of LTG improved seizure control, suggesting that in some patients with Dravet syndrome, LTG may be beneficial.

Mermaid syndrome: virtually no hope for survival.

Sirenomelia, also called the mermaid syndrome is a severe malformation involving multiple organs and characterized by partially or completely developed lower extremities fused by the skin. The birth of a "mermaid" is very rare (1.2-4.2 cases for 100,000 births); most are stillborn, or die at or shortly after birth. The case of a living female neonate with dipodic simelia (fusion of well-developed legs) is presented. No prenatal diagnosis was made and the newborn had an uneventful neonatal course following Cesarean section delivery. The complex and striking malformation was obvious at birth and further evaluation revealed very poorly functioning kidneys, associated with abnormal anorectum, urogenital tract, and external genitalia, as well as a pelvic malformation. Supportive care was applied because of the poor prognosis and the child died at 7 weeks of age, due to renal failure.

Enhanced heat shock protein 70 expression alters proteasomal degradation of IkappaB kinase in experimental acute respiratory distress syndrome.

OBJECTIVES: Acute respiratory distress syndrome is a common and highly lethal inflammatory lung syndrome. We previously have shown that an adenoviral vector expressing the heat shock protein (Hsp)70 (AdHSP) protects against experimental sepsis-induced acute respiratory distress syndrome in part by limiting neutrophil accumulation in the lung. Neutrophil accumulation and activation is modulated, in part, by the nuclear factor-kappaB (NF-kappaB) signal transduction pathway. NF-kappaB activation requires dissociation/degradation of a bound inhibitor, IkappaBalpha. IkappaBalpha degradation requires phosphorylation by IkappaB kinase, ubiquitination by the SCFbeta-TrCP (Skp1/Cullin1/Fbox beta-transducing repeat-containing protein) ubiquitin ligase, and degradation by the 26S proteasome. We tested the hypothesis that Hsp70 attenuates NF-kappaB activation at multiple points in the IkappaBalpha degradative pathway. DESIGN: Laboratory investigation. SETTING: University medical center research laboratory. SUBJECTS: Adolescent (200 g) Sprague-Dawley rats and murine lung epithelial-12 cells in culture. INTERVENTIONS: Lung injury was induced in rats via cecal ligation and double puncture. Thereafter, animals were treated with intratracheal injection of 1) phosphate buffer saline, 2) AdHSP, or 3) an adenovirus expressing green fluorescent protein. Murine lung epithelial-12 cells were stimulated with tumor necrosis factor-alpha and transfected. NF-kappaB was examined using molecular biological tools. MEASUREMENTS AND MAIN RESULTS: Intratracheal administration of AdHSP to rats with cecal ligation and double puncture limited nuclear translocation of NF-kappaB and attenuated phosphorylation of IkappaBalpha. AdHSP treatment reduced, but did not eliminate, phosphorylation of the beta-subunit of IkappaB kinase. In vitro kinase activity assays and gel filtration chromatography revealed that treatment of sepsis-induced lung injury with AdHSP induced fragmentation of the IkappaB kinase signalosome. This stabilized intermediary complexes containing IkappaB kinase components, IkappaBalpha, and NF-kappaB. Cellular studies indicate that although ubiquitination of IkappaBalpha was maintained, proteasomal degradation was impaired by an indirect mechanism. CONCLUSIONS: Treatment of sepsis-induced lung injury with AdHSP limits NF-kappaB activation. This results from stabilization of intermediary NF-kappaB/IkappaBalpha/IkappaB kinase complexes in a way that impairs proteasomal degradation of IkappaBalpha. This novel mechanism by which Hsp70 attenuates an intracellular process may be of therapeutic value.

New electrocardiographic criteria for discriminating between Brugada types 2 and 3 patterns and incomplete right bundle branch block.

OBJECTIVES: The aim of this study was to evaluate new electrocardiographic (ECG) criteria for discriminating between incomplete right bundle branch block (RBBB) and the Brugada types 2 and 3 ECG patterns. BACKGROUND: Brugada syndrome can manifest as either type 2 or type 3 pattern. The latter should be distinguished from incomplete RBBB, present in 3% of the population. METHODS: Thirty-eight patients with either type 2 or type 3 Brugada pattern that were referred for an antiarrhythmic drug challenge (AAD) were included. Before AAD, 2 angles were measured from ECG leads V(1) and/or V(2) showing incomplete RBBB: 1) α, the angle between a vertical line and the downslope of the r'-wave, and 2) β, the angle between the upslope of the S-wave and the downslope of the r'-wave. Baseline angle values, alone or combined with QRS duration, were compared between patients with negative and positive results on AAD. Receiver-operating characteristic curves were constructed to identify optimal discriminative cutoff values. RESULTS: The mean β angle was significantly smaller in the 14 patients with negative results on AAD compared to the 24 patients with positive results on AAD (36 ± 20° vs. 62 ± 20°, p < 0.01). Its optimal cutoff value was 58°, which yielded a positive predictive value of 73% and a negative predictive value of 87% for conversion to type 1 pattern on AAD; α was slightly less sensitive and specific compared with β. When the angles were combined with QRS duration, it tended to improve discrimination. CONCLUSIONS: In patients with suspected Brugada syndrome, simple ECG criteria can enable discrimination between incomplete RBBB and types 2 and 3 Brugada patterns.

Deletion of Sirt3 does not affect atherosclerosis but accelerates weight gain and impairs rapid metabolic adaptation in LDL receptor knockout mice: implications for cardiovascular risk factor development.

Sirt3 is a mitochondrial NAD(+)-dependent deacetylase that governs mitochondrial metabolism and reactive oxygen species homeostasis. Sirt3 deficiency has been reported to accelerate the development of the metabolic syndrome. However, the role of Sirt3 in atherosclerosis remains enigmatic. We aimed to investigate whether Sirt3 deficiency affects atherosclerosis, plaque vulnerability, and metabolic homeostasis. Low-density lipoprotein receptor knockout (LDLR(-/-)) and LDLR/Sirt3 double-knockout (Sirt3(-/-)LDLR(-/-)) mice were fed a high-cholesterol diet (1.25 % w/w) for 12 weeks. Atherosclerosis was assessed en face in thoraco-abdominal aortae and in cross sections of aortic roots. Sirt3 deletion led to hepatic mitochondrial protein hyperacetylation. Unexpectedly, though plasma malondialdehyde levels were elevated in Sirt3-deficient mice, Sirt3 deletion affected neither plaque burden nor features of plaque vulnerability (i.e., fibrous cap thickness and necrotic core diameter). Likewise, plaque macrophage and T cell infiltration as well as endothelial activation remained unaltered. Electron microscopy of aortic walls revealed no difference in mitochondrial microarchitecture between both groups. Interestingly, loss of Sirt3 was associated with accelerated weight gain and an impaired capacity to cope with rapid changes in nutrient supply as assessed by indirect calorimetry. Serum lipid levels and glucose tolerance were unaffected by Sirt3 deletion in LDLR(-/-) mice. Sirt3 deficiency does not affect atherosclerosis in LDLR(-/-) mice. However, Sirt3 controls systemic levels of oxidative stress, limits expedited weight gain, and allows rapid metabolic adaptation. Thus, Sirt3 may contribute to postponing cardiovascular risk factor development.

Combined pulmonary fibrosis and emphysema syndrome in connective tissue disease.

OBJECTIVE: Connective tissue diseases (CTDs) are associated with several interstitial lung diseases. The aim of this study was to describe the recently individualized syndrome of combined pulmonary fibrosis and emphysema (CPFE) in a population of patients with CTD. METHODS: In this multicenter study, we retrospectively investigated data from patients with CTD who also have CPFE. The demographic characteristics of the patients, the results of pulmonary function testing, high-resolution computed tomography, lung biopsy, and treatment, and the outcomes of the patients were analyzed. RESULTS: Data from 34 patients with CTD who were followed up for a mean±SD duration of 8.3±7.0 years were analyzed. Eighteen of the patients had rheumatoid arthritis (RA), 10 had systemic sclerosis (SSc), 4 had mixed or overlap CTD, and 2 had other CTDs. The mean±SD age of the patients was 57±11 years, 23 were men, and 30 were current or former smokers. High-resolution computed tomography revealed emphysema of the upper lung zones and pulmonary fibrosis of the lower zones in all patients, and all patients exhibited dyspnea during exercise. Moderately impaired pulmonary function test results and markedly reduced carbon monoxide transfer capacity were observed. Five patients with SSc exhibited pulmonary hypertension. Four patients died during followup. Patients with CTD and CPFE were significantly younger than an historical control group of patients with idiopathic CPFE and more frequently were female. In addition, patients with CTD and CPFE had higher lung volumes, lower diffusion capacity, higher pulmonary pressures, and more frequently were male than those with CTD and lung fibrosis without emphysema. CONCLUSION: CPFE warrants inclusion as a novel, distinct pulmonary manifestation within the spectrum of CTD-associated lung diseases in smokers or former smokers, especially in patients with RA or SSc.

Discriminating irritable bowel syndrome from inflammatory bowel disease: what is the role of biomarkers in daily practice?

Background and Aims: Discriminating irritable bowel syndrome (IBS) from inflammatorybowel disease (IBD) can be a clinical challenge as symptoms can overlap. We and othershave recently shown that fecal calprotectin (FC) is more accurate for discriminating IBSfrom IBD compared to C-reactive protein (CRP) and blood leukocytes. Data on the biomarkersused in daily gastroenterological practice are lacking. We therefore aimed to assess whichbiomarkers are used by gastroenterologists in their daily practice for discriminating IBSfrom IBD.Methods: A questionnaire was sent to all board certified gastroenterologists inSwitzerland focusing on demographic informations, number of IBS patients treated in thetime period from May 2009 to April 2010, and the specific biomarkers evaluated fordiscriminating IBS from IBD.Results: Response rate was 57% (153/270). Mean physician'sage was 50±9years, mean duration of gastroenterologic practice 14±8years, 52% of themwere working in private practice and 48% in hospitals. Thirty-nine percent had taken careof more than 100 IBS patients in the last 12 months, 37% had seen 41-100 and 24% hadseen 1-40 IBS patients. Gastroenterologists in private practice more frequently took care ofat least 40 IBS patients in a year compared to hospital-based gastroenterologists (P<0.001).The following biomarkers were determined for discriminating IBS from IBD: CRP 100%,FC 79%, hematogram (red blood cells and leukocytes) 70%, iron status (ferritin, transferrinsaturation) 59%, erythrocyte sedimentation rate 2.7%, protein electrophoresis 0.7%, andalpha-1 antitrypsin clearance 0.7%. There was a trend for using FC more often in privatepractice than in hospital (P = 0.08). Twenty-four percent of gastroenterologists had usedFC in the workup of more than 70% of patients classified as IBS, 22% had used FC in 30-70% of IBS patients, 39% in less than 30%, and 15% had never used FC for the work-upof suspected IBS. Eighty-nine percent of gastroenterologists considered FC to be superiorto CRP for discriminating IBS from IBD, 87% thought that patient's compliance for fecalsampling is high, and 51% judged the fee of USD 60 for a FC test as appropriate.Conclusions:FC is widely used in clinical practice to discriminate IBS from IBD. In accordance with thescientific evidence, the majority of gastroenterologists consider FC to be more accurate thanCRP for discriminating IBS from IBD. Gastroenterologists in private practice take care ofsignificantly more IBS patients than colleagues in hospital.

Relation between atherogenic dyslipidemia and the Adult Treatment Program-III definition of metabolic syndrome (Genetic Epidemiology of Metabolic Syndrome Project).

Genetic Epidemiology of Metabolic Syndrome is a multinational, family-based study to explore the genetic basis of the metabolic syndrome. Atherogenic dyslipidemia (defined as low plasma high-density lipoprotein cholesterol with elevated triglycerides (&lt;25th and &gt;75th percentile for age, gender, and country, respectively) identified affected subjects for the metabolic syndrome. This report examines the frequency at which atherogenic dyslipidemia predicts the metabolic syndrome of the National Cholesterol Education Program Adult Treatment Panel III (ATP-III). One thousand four hundred thirty-six (854 men/582 women) affected patients by our criteria were compared with 1,672 (737 men/935 women) unaffected persons. Affected patients had more hypertension, obesity, and hyperglycemia, and they met a higher number of ATP-III criteria (3.2 +/- 1.1 SD vs 1.3 +/- 1.1 SD, p &lt;0.001). Overall, 76% of affected persons also qualified for the ATP-III definition (Cohen's kappa 0.61, 95% confidence interval 0.59 to 0.64), similar to a separate group of 464 sporadic, unrelated cases (75%). Concordance increased from 41% to 82% and 88% for ages &lt; or =35, 36 to 55, and &gt; or =55 years, respectively. Affected status was also independently associated with waist circumference (p &lt;0.001) and fasting glucose (p &lt;0.001) but not systolic blood pressure (p = 0.43). Thus, the lipid-based criteria used to define affection status in this study substantially parallels the ATP-III definition of metabolic syndrome in subjects aged &gt;35 years. In subjects aged &lt;35 years, atherogenic dyslipidemia frequently occurs in the absence of other metabolic syndrome risk factors.

Genetic and phenotypic architecture of metabolic syndrome-associated components in dyslipidemic and normolipidemic subjects: the GEMS Study.

Atherogenic dyslipidemia, manifest by low HDL-cholesterol and high TG levels, is an important component of ATP-III defined metabolic syndrome. Here, we dissected the phenotypic and genetic architecture of these traits by assessing their relationships with other metabolically relevant measures, including plasma adipo-cytokines, highly sensitive C-reactive protein (hsCRP) and LDL particle size, in a large family data set (n=2800) and in an independent set of dyslipidemic cases (n=716) and normolipidemic controls (n=1073). We explored the relationships among these phenotypes using variable clustering and then estimated their genetic heritabilities and cross-trait correlations. In families, four clusters explained 61% of the total variance, with one adiposity-related cluster (including hsCRP), one BP-related cluster, and two lipid-related clusters (HDL-C, TG, adiponectin and LDL particle size; apoB and non-HDL-C). A similar structure was observed in dyslipidemic cases and normolipidemic controls. The genetic correlations in the families largely paralleled the phenotype clustering results, suggesting that common genes having pleiotropic effects contributed to the correlations observed. In summary, our analyses support a model of metabolic syndrome with two major components, body fat and lipids, each with two subcomponents, and quantifies their degree of overlap with each other and with metabolic-syndrome related measures (adipokines, LDL particle size and hsCRP).