Aorto-bronchial and aorto-pulmonary fistulation after thoracic endovascular aortic repair: an analysis from the European Registry of Endovascular Aortic Repair Complications

OBJECTIVES To learn upon incidence, underlying mechanisms and effectiveness of treatment strategies in patients with central airway and pulmonary parenchymal aorto-bronchial fistulation after thoracic endovascular aortic repair (TEVAR). METHODS Analysis of an international multicentre registry (European Registry of Endovascular Aortic Repair Complications) between 2001 and 2012 with a total caseload of 4680 TEVAR procedures (14 centres). RESULTS Twenty-six patients with a median age of 70 years (interquartile range: 60-77) (35% female) were identified. The incidence of either central airway (aorto-bronchial) or pulmonary parenchymal (aorto-pulmonary) fistulation (ABPF) in the entire cohort after TEVAR in the study period was 0.56% (central airway 58%, peripheral parenchymal 42%). Atherosclerotic aneurysm formation was the leading indication for TEVAR in 15 patients (58%). The incidence of primary endoleaks after initial TEVAR was n = 10 (38%), of these 80% were either type I or type III endoleaks. Fourteen patients (54%) developed central left bronchial tree lesions, 11 patients (42%) pulmonary parenchymal lesions and 1 patient (4%) developed a tracheal lesion. The recognized mechanism of ABPF was external compression of the bronchial tree in 13 patients (50%), the majority being due to endoleak formation, further ischaemia due to extensive coverage of bronchial feeding arteries in 3 patients (12%). Inflammation and graft erosion accounted for 4 patients (30%) each. Cumulative survival during the entire study period was 39%. Among deaths, 71% were attributed to ABPF. There was no difference in survival in patients having either central airway or pulmonary parenchymal ABPF (33 vs 45%, log-rank P = 0.55). Survival with a radical surgical approach was significantly better when compared with any other treatment strategy in terms of overall survival (63 vs 32% and 63 vs 21% at 1 and 2 years, respectively), as well as in terms of fistula-related survival (63 vs 43% and 63 vs 43% at 1 and 2 years, respectively). CONCLUSIONS ABPF is a rare but highly lethal complication after TEVAR. The leading mechanism behind ABPF seems to be a continuing external compression of either the bronchial tree or left upper lobe parenchyma. In this setting, persisting or newly developing endoleak formation seems to play a crucial role. Prognosis does not differ in patients with central airway or pulmonary parenchymal fistulation. Radical bronchial or pulmonary parenchymal repair in combination with stent graft removal and aortic reconstruction seems to be the most durable treatment strategy.

Flavour-violation in two-Higgs-doublet models

In these proceedings we review the flavour phenomenology of 2HDMs with generic Yukawa structures [1]. We first consider the quark sector and find that despite the stringent constraints from FCNC processes large effects in tauonic B decays are still possible. We then consider lepton flavour observables, show correlations between m →eg and m− →e−e+e− in the 2HDM of type III and give upper bounds on the lepton flavour violating B decay Bd →me.

Irisin – a myth rather than an exercise-inducible myokine

The myokine irisin is supposed to be cleaved from a transmembrane precursor, FNDC5 (fibronectin type III domain containing 5), and to mediate beneficial effects of exercise on human metabolism. However, evidence for irisin circulating in blood is largely based on commercial ELISA kits which are based on polyclonal antibodies (pAbs) not previously tested for cross-reacting serum proteins. We have analyzed four commercial pAbs by Western blotting, which revealed prominent cross-reactivity with non-specific proteins in human and animal sera. Using recombinant glycosylated and non-glycosylated irisin as positive controls, we found no immune-reactive bands of the expected size in any biological samples. A FNDC5 signature was identified at ~20 kDa by mass spectrometry in human serum but was not detected by the commercial pAbs tested. Our results call into question all previous data obtained with commercial ELISA kits for irisin, and provide evidence against a physiological role for irisin in humans and other species.

A mouse model for S. typhimurium-induced enterocolitis.

Salmonella typhimurium has emerged as a model pathogen that manipulates host cells in a complex fashion, thus causing disease. In humans, S. typhimurium causes acute intestinal inflammation. Intriguingly, type III secreted virulence proteins have a central role in this process. At the cellular level, the functions of these factors are well characterized; at present, animal models are required for elucidating how these factors trigger inflammatory disease in vivo. Calf infection models have been employed successfully and, recently, a mouse model was identified: in streptomycin-pretreated mice, S. typhimurium causes acute colitis. This mouse model provides a new avenue for research into acute intestinal inflammation because it enables the manipulation and dissection of both the bacterial and host contributions to the disease in unsurpassed detail.

Comparison of Salmonella enterica serovar Typhimurium colitis in germfree mice and mice pretreated with streptomycin.

Salmonella enterica subspecies 1 serovar Typhimurium is a common cause of bacterial enterocolitis. Mice are generally protected from Salmonella serovar Typhimurium colonization and enterocolitis by their resident intestinal microflora. This phenomenon is called "colonization resistance" (CR). Two murine Salmonella serovar Typhimurium infection models are based on the neutralization of CR: (i) in specific-pathogen-free mice pretreated with streptomycin (StrSPF mice) antibiotics disrupt the intestinal microflora; and (ii) germfree (GF) mice are raised without any intestinal microflora, but their intestines show distinct physiologic and immunologic characteristics. It has been unclear whether the same pathogenetic mechanisms trigger Salmonella serovar Typhimurium colitis in GF and StrSPF mice. In this study, we compared the two colitis models. In both of the models Salmonella serovar Typhimurium efficiently colonized the large intestine and triggered cecum and colon inflammation starting 8 h postinfection. The type III secretion system encoded in Salmonella pathogenicity island 1 was essential in both disease models. Thus, Salmonella serovar Typhimurium colitis is triggered by similar pathogenetic mechanisms in StrSPF and GF mice. This is remarkable considering the distinct physiological properties of the GF mouse gut. One obvious difference was more pronounced damage and reduced regenerative response of the cecal epithelium in GF mice. Overall, StrSPF mice and GF mice provide similar but not identical models for Salmonella serovar Typhimurium colitis.

Flagella and chemotaxis are required for efficient induction of Salmonella enterica serovar Typhimurium colitis in streptomycin-pretreated mice.

Salmonella enterica subspecies 1 serovar Typhimurium is a common cause of gastrointestinal infections. The host's innate immune system and a complex set of Salmonella virulence factors are thought to contribute to enteric disease. The serovar Typhimurium virulence factors have been studied extensively by using tissue culture assays, and bovine infection models have been used to verify the role of these factors in enterocolitis. Streptomycin-pretreated mice provide an alternative animal model to study enteric salmonellosis. In this model, the Salmonella pathogenicity island 1 type III secretion system has a key virulence function. Nothing is known about the role of other virulence factors. We investigated the role of flagella in murine serovar Typhimurium colitis. A nonflagellated serovar Typhimurium mutant (fliGHI) efficiently colonized the intestine but caused little colitis during the early phase of infection (10 and 24 h postinfection). In competition assays with differentially labeled strains, the fliGHI mutant had a reduced capacity to get near the intestinal epithelium, as determined by fluorescence microscopy. A flagellated but nonchemotactic cheY mutant had the same virulence defects as the fliGHI mutant for causing colitis. In competitive infections, both mutants colonized the intestine of streptomycin-pretreated mice by day 1 postinfection but were outcompeted by the wild-type strain by day 3 postinfection. Together, these data demonstrate that flagella are required for efficient colonization and induction of colitis in streptomycin-pretreated mice. This effect is mostly attributable to chemotaxis. Recognition of flagellar subunits (i.e., flagellin) by innate immune receptors (i.e., Toll-like receptor 5) may be less important.

Role of the Salmonella pathogenicity island 1 effector proteins SipA, SopB, SopE, and SopE2 in Salmonella enterica subspecies 1 serovar Typhimurium colitis in streptomycin-pretreated mice.

Salmonella enterica subspecies 1 serovar Typhimurium (serovar Typhimurium) induces enterocolitis in humans and cattle. The mechanisms of enteric salmonellosis have been studied most extensively in calf infection models. The previous studies established that effector protein translocation into host cells via the Salmonella pathogenicity island 1 (SPI-1) type III secretion system (TTSS) is of central importance in serovar Typhimurium enterocolitis. We recently found that orally streptomycin-pretreated mice provide an alternative model for serovar Typhimurium colitis. In this model the SPI-1 TTSS also plays a key role in the elicitation of intestinal inflammation. However, whether intestinal inflammation in calves and intestinal inflammation in streptomycin-pretreated mice are induced by the same SPI-1 effector proteins is still unclear. Therefore, we analyzed the role of the SPI-1 effector proteins SopB/SigD, SopE, SopE2, and SipA/SspA in elicitation of intestinal inflammation in the murine model. We found that sipA, sopE, and, to a lesser degree, sopE2 contribute to murine colitis, but we could not assign an inflammation phenotype to sopB. These findings are in line with previous studies performed with orally infected calves. Extending these observations, we demonstrated that in addition to SipA, SopE and SopE2 can induce intestinal inflammation independent of each other and in the absence of SopB. In conclusion, our data corroborate the finding that streptomycin-pretreated mice provide a useful model for studying the molecular mechanisms of serovar Typhimurium colitis and are an important starting point for analysis of the molecular events triggered by SopE, SopE2, and SipA in vivo.

Pretreatment of mice with streptomycin provides a Salmonella enterica serovar Typhimurium colitis model that allows analysis of both pathogen and host.

Salmonella enterica subspecies 1 serovar Typhimurium is a principal cause of human enterocolitis. For unknown reasons, in mice serovar Typhimurium does not provoke intestinal inflammation but rather targets the gut-associated lymphatic tissues and causes a systemic typhoid-like infection. The lack of a suitable murine model has limited the analysis of the pathogenetic mechanisms of intestinal salmonellosis. We describe here how streptomycin-pretreated mice provide a mouse model for serovar Typhimurium colitis. Serovar Typhimurium colitis in streptomycin-pretreated mice resembles many aspects of the human infection, including epithelial ulceration, edema, induction of intercellular adhesion molecule 1, and massive infiltration of PMN/CD18(+) cells. This pathology is strongly dependent on protein translocation via the serovar Typhimurium SPI1 type III secretion system. Using a lymphotoxin beta-receptor knockout mouse strain that lacks all lymph nodes and organized gut-associated lymphatic tissues, we demonstrate that Peyer's patches and mesenteric lymph nodes are dispensable for the initiation of murine serovar Typhimurium colitis. Our results demonstrate that streptomycin-pretreated mice offer a unique infection model that allows for the first time to use mutants of both the pathogen and the host to study the molecular mechanisms of enteric salmonellosis.

Oligodeoxynucleotide Duplexes Containing (5′S)-5′-C-Alkyl-Modified 2′-Deoxynucleosides: Can an Alkyl Zipper across the DNA Minor-Groove Enhance Duplex Stability?

10.1002/hlca.200390311.abs A series of oligonucleotides containing (5′S)-5′-C-butyl- and (5′S)-5′-C-isopentyl-substituted 2′-deoxyribonucleosides were designed, prepared, and characterized with the intention to explore alkyl-zipper formation between opposing alkyl chains across the minor groove of oligonucleotide duplexes as a means to modulate DNA-duplex stability. From four possible arrangements of the alkyl groups that differ in the density of packing of the alkyl chains across the minor groove, three (duplex types I–III, Fig. 2) could experimentally be realized and their duplex-forming properties analyzed by UV-melting curves, CD spectroscopy, and isothermal titration calorimetry (ITC), as well as by molecular modeling. The results show that all arrangements of alkyl residues within the minor groove of DNA are thermally destabilizing by 1.5–3°/modification in Tm. We found that, within the proposed duplexes with more loosely packed alkyl groups (type-III duplexes), accommodation of alkyl residues without extended distorsion of the helical parameters of B-DNA is possible but does not lead to higher thermodynamic stability. The more densely packed and more unevenly distributed arrangement (type-II duplexes) seems to suffer from ecliptic positioning of opposite alkyl groups, which might account for a systematic negative contribution to stability due to steric interactions. The decreased stability in the type-III duplexes described here may be due either to missing hydrophobic interactions of the alkyl groups (not bulky enough to make close contacts), or to an overcompensation of favorable alkyl-zipper formation presumably by loss of structured H2O in the minor groove.

Sodium-Dependent Phosphate Transporters in Osteoclast Differentiation and Function

Osteoclasts are multinucleated bone degrading cells. Phosphate is an important constituent of mineralized bone and released in significant quantities during bone resorption. Molecular contributors to phosphate transport during the resorptive activity of osteoclasts have been controversially discussed. This study aimed at deciphering the role of sodium-dependent phosphate transporters during osteoclast differentiation and bone resorption. Our studies reveal RANKL-induced differential expression of sodium-dependent phosphate transport protein IIa (NaPi-IIa) transcript and protein during osteoclast development, but no expression of the closely related NaPi-IIb and NaPi-IIc SLC34 family isoforms. In vitro studies employing NaPi-IIa-deficient osteoclast precursors and mature osteoclasts reveal that NaPi-IIa is dispensable for bone resorption and osteoclast differentiation. These results are supported by the analysis of structural bone parameters by high-resolution microcomputed tomography that yielded no differences between adult NaPi-IIa WT and KO mice. By contrast, both type III sodium-dependent phosphate transporters Pit-1 and Pit-2 were abundantly expressed throughout osteoclast differentiation, indicating that they are the relevant sodium-dependent phosphate transporters in osteoclasts and osteoclast precursors. We conclude that phosphate transporters of the SLC34 family have no role in osteoclast differentiation and function and propose that Pit-dependent phosphate transport could be pivotal for bone resorption and should be addressed in further studies.

Operative Treatment of Acute Fractures of the Tarsal Navicular Body: Midterm Results With a New Classification.

BACKGROUND Treatment of displaced tarsal navicular body fractures usually consists of open reduction and internal fixation. However, there is little literature reporting results of this treatment and correlation to fracture severity. METHODS We report the results of 24 patients treated in our institution over a 12-year period. Primary outcome measurements were Visual-Analogue-Scale Foot and Ankle score (VAS-FA), AOFAS midfoot score, and talonavicular osteoarthritis at final follow-up. According to a new classification system reflecting talonavicular joint damage, 2-part fractures were classified as type I, multifragmentary fractures as type II, and fractures with talonavicular joint dislocation and/or concomitant talar head fractures as type III. Spearman's coefficients tested this classification's correlation with the primary outcome measurements. Mean patient age was 33 (range 16-61) years and mean follow-up duration 73 (range 24-159) months. RESULTS Average VAS-FA score was 74.7 (standard deviation [SD] 16.9), and average AOFAS midfoot score was 83.8 (SD = 12.8). Final radiographs showed no talonavicular arthritis in 5 patients, grade 1 in 7, grade 2 in 3, grade 3 in 6, and grade 4 in 1 patient. Two patients had secondary or spontaneous talonavicular fusion. Spearman coefficients showed strong correlation of the classification system with VAS-FA score (r = -0.663, P < .005) and talonavicular arthritis (r = 0.600, P = .003), and moderate correlation with AOFAS score (r = -.509, P = .011). CONCLUSION At midterm follow-up, open reduction and internal fixation of navicular body fractures led to good clinical outcome but was closely related to fracture severity. A new classification based on the degree of talonavicular joint damage showed close correlation to clinical and radiologic outcome. LEVEL OF EVIDENCE Level IV, retrospective case series.

Retraction

Vareille M, Kieninger E, Alves MP, et al. Impaired type I and type III interferon induction and rhinovirus control in human cystic fibrosis airway epithelial cells. Thorax 2012;67:517-25. This article has been retracted. In our article recently published in Thorax, we described a novel mechanism explaining the increased susceptibility of patients with cystic fibrosis (CF) to rhinovirus infections, namely defective interferon type I and III production by CF airway epithelial cells. In experiments performed after publication of the article we were unable to consistently replicate our findings of deficient interferon type I and III production by CF airway epithelial cells upon rhinovirus infection. In the light of these results, we carried out detailed investigations of the data reported in the above manuscript and regrettably found evidence of deliberate manipulation of experimental data by the first author Dr M. Vareille. This manipulation was accompanied in some instances by absence of original data files. The manipulation/original data absence involved data presented in most, if not all of the figures, thus we wish to fully retract the paper and apologise to the readers of Thorax and to the scientific community for the inconvenience this has caused. We also checked data published by our group in manuscripts on which Dr Vareille was a co-author and found that data published in these manuscripts had not been manipulated. These two manuscripts, whose data and conclusions we stand by are: Edwards MR, Regamey N, Vareille M, et al. Impaired innate interferon induction in severe therapy resistant atopic asthmatic children. Mucosal Immunol 2013;6:797–806. doi: 10.1038/mi.2012.118. and Kieninger E, Vareille M, Kopf BS, et al. Lack of an exaggerated inflammatory response on virus infection in cystic fibrosis. Eur Respir J 2012;39:297–304. doi: 10.1183/09031936.00054511. Dr. Vareille has received a letter from the Secretary General of the University of Bern condemning her scientific misconduct as a severe offence against the rules of scientific integrity. Her current employers have also been informed. All co-authors of the publication including Dr. Vareille concur with the retraction statement.

Direct electrospinning of 3D auricle-shaped scaffolds for tissue engineering applications.

Thirty-two poly(ε)caprolactone (PCL) scaffolds have been produced by electrospinning directly into an auricle-shaped mould and seeded with articular chondrocytes harvested from bovine ankle joints. After seeding, the auricle shaped constructs were cultured in vitro and analysed at days 1, 7, 14 and 21 for regional differences in total DNA, glycosaminoglycan (GAG) and collagen (COL) content as well as the expression of aggrecan (AGG), collagen type I and type II (COL1/2) and matrix metalloproteinase 3 and 13 (MMP3/13). Stress-relaxation indentation testing was performed to investigate regional mechanical properties of the electrospun constructs. Electrospinning into a conductive mould yielded stable 3D constructs both initially and for the whole in vitro culture period, with an equilibrium modulus in the MPa range. Rapid cell proliferation and COL accumulation was observed until week 3. Quantitative real time PCR analysis showed an initial increase in AGG, no change in COL2, a persistent increase in COL1, and only a slight decrease initially for MMP3. Electrospinning of fibrous scaffolds directly into an auricle-shape represents a promising option for auricular tissue engineering, as it can reduce the steps needed to achieve an implantable structure.

Aggretin, a heterodimeric C-type lectin from Calloselasma rhodostoma (malayan pit viper), stimulates platelets by binding to alpha 2beta 1 integrin and glycoprotein Ib, activating Syk and phospholipase Cgamma 2, but does not involve the glycoprotein VI/Fc receptor gamma chain collagen receptor

Aggretin, a potent platelet activator, was isolated from Calloselasma rhodostoma venom, and 30-amino acid N-terminal sequences of both subunits were determined. Aggretin belongs to the heterodimeric snake C-type lectin family and is thought to activate platelets by binding to platelet glycoprotein alpha(2)beta(1). We now show that binding to glycoprotein (GP) Ib is also required. Aggretin-induced platelet activation was inhibited by a monoclonal antibody to GPIb as well as by antibodies to alpha(2)beta(1). Binding of both of these platelet receptors to aggretin was confirmed by affinity chromatography. No binding of other major platelet membrane glycoproteins, in particular GPVI, to aggretin was detected. Aggretin also activates platelets from Fc receptor gamma chain (Fcgamma)-deficient mice to a greater extent than those from normal control mice, showing that it does not use the GPVI/Fcgamma pathway. Platelets from Fcgamma-deficient mice expressed fibrinogen receptors normally in response to collagen, although they did not aggregate, indicating that these platelets may partly compensate via other receptors including alpha(2)beta(1) or GPIb for the lack of the Fcgamma pathway. Signaling by aggretin involves a dose-dependent lag phase followed by rapid tyrosine phosphorylation of a number of proteins. Among these are p72(SYK), p125(FAK), and PLCgamma2, whereas, in comparison with collagen and convulxin, the Fcgamma subunit neither is phosphorylated nor coprecipitates with p72(SYK). This supports an independent, GPIb- and integrin-based pathway for activation of p72(SYK) not involving the Fcgamma receptor.

Platelet activation and signal transduction by convulxin, a C-type lectin from Crotalus durissus terrificus (tropical rattlesnake) venom via the p62/GPVI collagen receptor

Convulxin, a powerful platelet activator, was isolated from Crotalus durissus terrificus venom, and 20 amino acid N-terminal sequences of both subunits were determined. These indicated that convulxin belongs to the heterodimeric C-type lectin family. Neither antibodies against GPIb nor echicetin had any effect on convulxin-induced platelet aggregation showing that, in contrast to other venom C-type lectins acting on platelets, GPIb is not involved in convulxin-induced platelet activation. In addition, partially reduced/denatured convulxin only affects collagen-induced platelet aggregation. The mechanism of convulxin-induced platelet activation was examined by platelet aggregation, detection of time-dependent tyrosine phosphorylation of platelet proteins, and binding studies with 125I-convulxin. Convulxin induces signal transduction in part like collagen, involving the time-dependent tyrosine phosphorylation of Fc receptor gamma chain, phospholipase Cgamma2, p72(SYK), c-Cbl, and p36-38. However, unlike collagen, pp125(FAK) and some other bands are not tyrosine-phosphorylated. Convulxin binds to a glycosylated 62-kDa membrane component in platelet lysate and to p62/GPVI immunoprecipitated by human anti-p62/GPVI antibodies. Convulxin subunits inhibit both aggregation and tyrosine phosphorylation in response to collagen. Piceatannol, a tyrosine kinase inhibitor with some specificity for p72(SYK), showed differential effects on collagen and convulxin-stimulated signaling. These results suggest that convulxin uses the p62/GPVI but not the alpha2beta1 part of the collagen signaling pathways to activate platelets. Occupation and clustering of p62/GPVI may activate Src family kinases phosphorylating Fc receptor gamma chain and, by a mechanism previously described in T- and B-cells, activate p72(SYK) that is critical for downstream activation of platelets.