Diagnosis and treatment of bacterial peritonitis in patients with gastrointestinal cancer: an observational multicenter study.

Background: Bacterial peritonitis (BP) in patients with gastrointestinal (GI) cancer has been poorly described, and its prevalence is unknown. Objectives: This study aimed to evaluate in patients with both GI cancer and ascites the prevalence of BP, associated features, mechanisms, prognosis, and the diagnostic performance of neutrophil count in ascites. Design: A retrospective, multicenter, observational study. Methods: All patients with GI cancer and ascites who underwent at least one paracentesis sample analyzed for bacteriology over a 1-year period were included. BP was defined by a positive ascites culture combined with clinical and/or biological signs compatible with infection. Secondary BP was defined as BP related to a direct intra-abdominal infectious source. Results: Five hundred fifty-seven ascites from 208 patients included were analyzed. Twenty-eight patients had at least one episode of BP and the annual prevalence rate of BP was 14%. Among the 28 patients with BP, 19 (65%) patients had proven secondary BP and 17 (59%) patients had multi-microbial BP, mainly due to Enterobacterales. A neutrophil count greater than 110/mm3 in ascites had negative and positive predictive values of 96% and 39%, respectively, for the diagnosis of BP. The median survival of patients with BP was 10 days (interquartile range 6-40) after the diagnosis. Conclusion: BP is not rare in patients with GI cancer and is associated with a poor short-term prognosis. When a patient with GI cancer is diagnosed with BP, a secondary cause should be sought. Further studies are needed to better define the best management of these patients.

Sex differences in vascular endothelial cells.

Endothelial cells are important constituents of blood vessels and play a critical role in vascular homeostasis. They do not only control the exchanges between the blood and the surrounding tissues, but are also essential in regulating blood flow, modulating immune-cell trafficking and controlling vascular growth and repair. Endothelial dysfunction leads to cardiovascular diseases and is characterized by deficiency in secretion of vasodilator molecules, elevated reactive oxygen species (ROS), expression of adhesion molecules and excretion of proinflammatory cytokines. The sex hormones, estrogens, androgens and progestogens, regulate endothelial functions. Because cardiovascular disease risk increases after menopause, it is believed that female hormones, estrogens and progestogens promote endothelial cell health and function whereas androgens, the male hormones, might be detrimental. However, as illustrated in the present review, the picture might not be that simple. In addition, sex influences endothelial cell physiology independently of sex hormones but at genetic level.

Active tuberculosis screening among the displaced population fleeing Ukraine, France, February to October 2022.

Persons fleeing Ukraine since February 2022 have potentially higher risk of tuberculosis (TB) vs all European Union countries. Interest of active TB screening among this population is debated and not widely adopted. In this screening intervention by a network of TB centres in France, the number needed to screen (NNS) was 862 to find one case. This experience shows that this strategy may be relevant for TB control in situations of massive displacement, similar to that following the Russian invasion.

Association of Healthcare and Aesthetic Procedures with Infections Caused by Nontuberculous Mycobacteria, France, 2012‒2020.

We describe nontuberculous mycobacteria (NTM) infections during 2012-2020 associated with health care and aesthetic procedures in France. We obtained epidemiologic data from the national early warning response system for healtcare-associated infections and data on NTM isolates from the National Reference Center for Mycobacteria. We compared clinical and environmental isolates by using whole-genome sequencing. The 85 original cases were reported after surgery (48, 56%), other invasive procedures (28, 33%) and other procedures (9, 11%). NTM isolates belonged to rapidly growing (73, 86%) and slowly growing (10, 12%) species; in 2 cases, the species was not identified. We performed environmental investigations for 38 (45%) cases; results for 12 (32%) were positive for the same NTM species as for the infection. In 10 cases that had environmental and clinical samples whose genomes were similar, the infection source was probably the water used in the procedures. NTM infections could be preventable by using sterile water in all invasive procedures.

Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome.

BACKGROUND: The LDLR (low-density lipoprotein receptor) in the liver is the major determinant of LDL-cholesterol levels in human plasma. The discovery of genes that regulate the activity of LDLR helps to identify pathomechanisms of hypercholesterolemia and novel therapeutic targets against atherosclerotic cardiovascular disease. METHODS: We performed a genome-wide RNA interference screen for genes limiting the uptake of fluorescent LDL into Huh-7 hepatocarcinoma cells. Top hit genes were validated by in vitro experiments as well as analyses of data sets on gene expression and variants in human populations. RESULTS: The knockdown of 54 genes significantly inhibited LDL uptake. Fifteen of them encode for components or interactors of the U2-spliceosome. Knocking down any one of 11 out of 15 genes resulted in the selective retention of intron 3 of LDLR. The translated LDLR fragment lacks 88% of the full length LDLR and is detectable neither in nontransfected cells nor in human plasma. The hepatic expression of the intron 3 retention transcript is increased in nonalcoholic fatty liver disease as well as after bariatric surgery. Its expression in blood cells correlates with LDL-cholesterol and age. Single nucleotide polymorphisms and 3 rare variants of one spliceosome gene, RBM25, are associated with LDL-cholesterol in the population and familial hypercholesterolemia, respectively. Compared with overexpression of wild-type RBM25, overexpression of the 3 rare RBM25 mutants in Huh-7 cells led to lower LDL uptake. CONCLUSIONS: We identified a novel mechanism of posttranscriptional regulation of LDLR activity in humans and associations of genetic variants of RBM25 with LDL-cholesterol levels.

Mycobacterium chimaera Genomics With Regard to Epidemiological and Clinical Investigations Conducted for an Open Chest Postsurgical Mycobacterium chimaera Infection Outbreak.

BACKGROUND: Postsurgical infections due to Mycobacterium chimaera appeared as a novel nosocomial threat in 2015, with a worldwide outbreak due to contaminated heater-cooler units used in open chest surgery. We report the results of investigations conducted in France including whole-genome sequencing comparison of patient and heater-cooler unit isolates. METHODS: We sought M. chimaera infection cases from 2010 onwards through national epidemiological investigations in health care facilities performing cardiopulmonary bypass, together with a survey on good practices and systematic heater-cooler unit microbial analyses. Clinical and heater-cooler unit isolates were subjected to whole-genome sequencing analyzed with regard to the reference outbreak strain Zuerich-1. RESULTS: Only 2 clinical cases were shown to be related to the outbreak, although 23% (41/175) of heater-cooler units were declared positive for M. avium complex. Specific measures to prevent infection were applied in 89% (50/56) of health care facilities, although only 14% (8/56) of them followed the manufacturer maintenance recommendations. Whole-genome sequencing comparison showed that the clinical isolates and 72% (26/36) of heater-cooler unit isolates belonged to the epidemic cluster. Within clinical isolates, 5-9 nonsynonymous single nucleotide polymorphisms were observed, among which an in vivo mutation in a putative efflux pump gene was observed in a clinical isolate obtained for 1 patient on antimicrobial treatment. CONCLUSIONS: Cases of postsurgical M. chimaera infections have been declared to be rare in France, although heater-cooler units were contaminated, as in other countries. Genomic analyses confirmed the connection to the outbreak and identified specific single nucleotide polymorphisms, including 1 suggesting fitness evolution in vivo.

Transendothelial transport of lipoproteins.

The accumulation of low-density lipoproteins (LDL) in the arterial wall plays a pivotal role in the initiation and pathogenesis of atherosclerosis. Conversely, the removal of cholesterol from the intima by cholesterol efflux to high density lipoproteins (HDL) and subsequent reverse cholesterol transport shall confer protection against atherosclerosis. To reach the subendothelial space, both LDL and HDL must cross the intact endothelium. Traditionally, this transit is explained by passive filtration. This dogma has been challenged by the identification of several rate-limiting factors namely scavenger receptor SR-BI, activin like kinase 1, and caveolin-1 for LDL as well as SR-BI, ATP binding cassette transporter G1, and endothelial lipase for HDL. In addition, estradiol, vascular endothelial growth factor, interleukins 6 and 17, purinergic signals, and sphingosine-1-phosphate were found to regulate transendothelial transport of either LDL or HDL. Thorough understanding of transendothelial lipoprotein transport is expected to elucidate new therapeutic targets for the treatment or prevention of atherosclerotic cardiovascular disease and the development of strategies for the local delivery of drugs or diagnostic tracers into diseased tissues including atherosclerotic lesions.

Neurological diseases of unknown etiology: Brain-biopsy diagnostic yields and safety.

BACKGROUND: For nonneoplastic neurological diseases, no recommendation exists regarding the place or appropriate timing of brain biopsy. The aim of this study was to evaluate the diagnostic yield and safety of brain biopsies from patients with neurological diseases of unknown etiology. METHODS: We performed a retrospective cohort study from January 1, 2008 to December 31, 2018. We analyzed 1847 brain-biopsied patients, including 178 biopsies indicated for neurological diseases of unknown etiology. Specific histological and final diagnosis rates, positive diagnosis-associated factors, complication rate and complication-associated factors were assessed. RESULTS: Specific histological diagnosis and final diagnosis rates were 71.3% and 83.1%, respectively, leading to therapeutic management change(s) for 75.3% of patients. Brain- biopsy-related mortality and permanent neurological morbidity occurred in 1.1% and 0.6% of the patients, respectively. The multivariable logistic-regression model retained (odds ratio [95% CI] only immunodepression (2.2 [1.1-4.7]; P=.04) as being independently associated with specific histological diagnosis, while supratentorial biopsy-targeted lesions (4.1 [1.1-15.2]; P=.04) were independently associated with a final diagnosis. Biopsies obtained from comatose patients were less contributive to the diagnosis (0.2 [0.05-0.7]; P=.01). Prebiopsy platelet count <100 G/L (28.5 [1.8-447]; P=.02), hydrocephalus (6.3 [1.2-15.3]; P=.02) and targeted lesions <1 cm (4.3 [1.2-15.3]; P=.03) were independently associated with brain biopsy-related complications. CONCLUSION: For highly selected patients with neurological diseases of unknown etiology, brain biopsy has a high diagnostic yield and low frequency of severe complications. We advocate that this procedure be considered early in the diagnosis algorithm of these patients.

Axl receptor tyrosine kinase is a regulator of apolipoprotein E.

Alzheimer's disease (AD), the leading cause of dementia, is a chronic neurodegenerative disease. Apolipoprotein E (apoE), which carries lipids in the brain in the form of lipoproteins, plays an undisputed role in AD pathophysiology. A high-throughput phenotypic screen was conducted using a CCF-STTG1 human astrocytoma cell line to identify small molecules that could upregulate apoE secretion. AZ7235, a previously discovered Axl kinase inhibitor, was identified to have robust apoE activity in brain microglia, astrocytes and pericytes. AZ7235 also increased expression of ATP-binding cassette protein A1 (ABCA1), which is involved in the lipidation and secretion of apoE. Moreover, AZ7235 did not exhibit Liver-X-Receptor (LXR) activity and stimulated apoE and ABCA1 expression in the absence of LXR. Target validation studies using AXL-/- CCF-STTG1 cells showed that Axl is required to mediate AZ7235 upregulation of apoE and ABCA1. Intriguingly, apoE expression and secretion was significantly attenuated in AXL-deficient CCF-STTG1 cells and reconstitution of Axl or kinase-dead Axl significantly restored apoE baseline levels, demonstrating that Axl also plays a role in maintaining apoE homeostasis in astrocytes independent of its kinase activity. Lastly, these effects may require human apoE regulatory sequences, as AZ7235 exhibited little stimulatory activity toward apoE and ABCA1 in primary murine glia derived from neonatal human APOE3 targeted-replacement mice. Collectively, we identified a small molecule that exhibits robust apoE and ABCA1 activity independent of the LXR pathway in human cells and elucidated a novel relationship between Axl and apoE homeostasis in human astrocytes.

Relevance of Dzyaloshinskii-Moriya spectral broadenings in promoting spin decoherence: a comparative pulsed-EPR study of two structurally related iron(iii) and chromium(iii) spin-triangle molecular qubits.

Spectral broadenings due to Dzyaloshinskii-Moriya interactions (DMI) were assessed with respect to the decoherence they induce through increased spin-spin interactions, as the role of DMI in developing magnetoelectric spin-chirality qubits is gaining recognition. The structurally related spin triangles [Fe3O(PhCOO)6(py)3]ClO4·py (Fe3) and [Cr3O(PhCOO)6(py)3]ClO4·0.5py (Cr3) were studied as frozen py-d5 solutions with various pulsed Electron Paramagnetic Resonance (EPR) spectroscopy experiments, and under identical experimental conditions. Field-swept Hahn echo experiments revealed a match with continuous-wave (CW) spectra, while variable-temperature saturation/inversion recovery and Hahn echo decay experiments were used to extract the thermal evolutions of the spin-lattice relaxation and phase-memory times (T1 and Tm, respectively). Nutation experiments revealed Rabi oscillations demonstrating that the spins of the complexes could be coherently manipulated. Careful comparisons of Tm times confirmed hyperfine interactions with the magnetic nuclei of the metal ions as an intrinsic source of decoherence. Comparisons of Rabi damping times revealed that DMI-induced spectral broadenings play a discernible but moderate role as an extrinsic source of decoherence for the nutation experiments and that they are not particularly detrimental to spin manipulations.

Small molecule inducers of ABCA1 and apoE that act through indirect activation of the LXR pathway.

apoE is the primary lipid carrier within the CNS and the strongest genetic risk factor for late onset Alzheimer's disease (AD). apoE is primarily lipidated via ABCA1, and both are under transcriptional regulation by the nuclear liver X receptor (LXR). Considerable evidence from genetic (using ABCA1 overexpression) and pharmacological (using synthetic LXR agonists) studies in AD mouse models suggests that increased levels of lipidated apoE can improve cognitive performance and, in some strains, can reduce amyloid burden. However, direct synthetic LXR ligands have hepatotoxic side effects that limit their clinical use. Here, we describe a set of small molecules, previously annotated as antagonists of the purinergic receptor, P2X7, which enhance ABCA1 expression and activity as well as apoE secretion, and are not direct LXR ligands. Furthermore, P2X7 is not required for these molecules to induce ABCA1 upregulation and apoE secretion, demonstrating that the ABCA1 and apoE effects are mechanistically independent of P2X7 inhibition. Hence, we have identified novel dual activity compounds that upregulate ABCA1 across multiple CNS cell types, including human astrocytes, pericytes, and microglia, through an indirect LXR mechanism and that also independently inhibit P2X7 receptor activity.

Surgery as an Adjunctive Treatment for Multidrug-Resistant Tuberculosis: An Individual Patient Data Metaanalysis.

BACKGROUND: Medical treatment for multidrug-resistant (MDR)-tuberculosis is complex, toxic, and associated with poor outcomes. Surgical lung resection may be used as an adjunct to medical therapy, with the intent of reducing bacterial burden and improving cure rates. We conducted an individual patient data metaanalysis to evaluate the effectiveness of surgery as adjunctive therapy for MDR-tuberculosis. METHODS: Individual patient data, was obtained from the authors of 26 cohort studies, identified from 3 systematic reviews of MDR-tuberculosis treatment. Data included the clinical characteristics and medical and surgical therapy of each patient. Primary analyses compared treatment success (cure and completion) to a combined outcome of failure, relapse, or death. The effects of all forms of resection surgery, pneumonectomy, and partial lung resection were evaluated. RESULTS: A total of 4238 patients from 18 surgical studies and 2193 patients from 8 nonsurgical studies were included. Pulmonary resection surgery was performed on 478 patients. Partial lung resection surgery was associated with improved treatment success (adjusted odds ratio [aOR], 3.0; 95% confidence interval [CI], 1.5-5.9; I(2)R, 11.8%), but pneumonectomy was not (aOR, 1.1; 95% CI, .6-2.3; I(2)R, 13.2%). Treatment success was more likely when surgery was performed after culture conversion than before conversion (aOR, 2.6; 95% CI, 0.9-7.1; I(2)R, 0.2%). CONCLUSIONS: Partial lung resection, but not pneumonectomy, was associated with improved treatment success among patients with MDR-tuberculosis. Although improved outcomes may reflect patient selection, partial lung resection surgery after culture conversion may improve treatment outcomes in patients who receive optimal medical therapy.

Reconstituted high-density lipoproteins acutely reduce soluble brain Aß levels in symptomatic APP/PS1 mice.

Many lines of evidence suggest a protective role for high-density lipoprotein (HDL) and its major apolipoprotein (apo)A-I in Alzheimer's Disease (AD). HDL/apoA-I particles are produced by the liver and intestine and, in addition to removing excess cholesterol from the body, are increasingly recognized to have vasoprotective functions. Here we tested the ability of reconstituted HDL (rHDL) consisting of human apoA-I reconstituted with soy phosphatidylcholine for its ability to lower amyloid beta (Aß) levels in symptomatic APP/PS1 mice, a well-characterized preclinical model of amyloidosis. Animals were treated intravenously either with four weekly doses (chronic study) or a single dose of 60mg/kg of rHDL (acute study). The major finding of our acute study is that soluble brain Aß40 and Aß42 levels were significantly reduced within 24h of a single dose of rHDL. By contrast, no changes were observed in our chronic study with respect to soluble or deposited Aß levels in animals assessed 7days after the final weekly dose of rHDL, suggesting that beneficial effects diminish as rHDL is cleared from the body. Further, rHDL-treated animals showed no change in amyloid burden, cerebrospinal fluid (CSF) Aß levels, neuroinflammation, or endothelial activation in the chronic study, suggesting that the pathology-modifying effects of rHDL may indeed be acute and may be specific to the soluble Aß pool. That systemic administration of rHDL can acutely modify brain Aß levels provides support for further investigation of the therapeutic potential of apoA-I-based agents for AD. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

In vitro fabrication of autologous living tissue-engineered vascular grafts based on prenatally harvested ovine amniotic fluid-derived stem cells.

Amniotic fluid cells (AFCs) have been proposed as a valuable source for tissue engineering and regenerative medicine. However, before clinical implementation, rigorous evaluation of this cell source in clinically relevant animal models accepted by regulatory authorities is indispensable. Today, the ovine model represents one of the most accepted preclinical animal models, in particular for cardiovascular applications. Here, we investigate the isolation and use of autologous ovine AFCs as cell source for cardiovascular tissue engineering applications. Fetal fluids were aspirated in vivo from pregnant ewes (n = 9) and from explanted uteri post mortem at different gestational ages (n = 91). Amniotic non-allantoic fluid nature was evaluated biochemically and in vivo samples were compared with post mortem reference samples. Isolated cells revealed an immunohistochemical phenotype similar to ovine bone marrow-derived mesenchymal stem cells (MSCs) and showed expression of stem cell factors described for embryonic stem cells, such as NANOG and STAT-3. Isolated ovine amniotic fluid-derived MSCs were screened for numeric chromosomal aberrations and successfully differentiated into several mesodermal phenotypes. Myofibroblastic ovine AFC lineages were then successfully used for the in vitro fabrication of small- and large-diameter tissue-engineered vascular grafts (n = 10) and cardiovascular patches (n = 34), laying the foundation for the use of this relevant pre-clinical in vivo assessment model for future amniotic fluid cell-based therapeutic applications.

Merging pathology with biomechanics using CHIMERA (Closed-Head Impact Model of Engineered Rotational Acceleration): a novel, surgery-free model of traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) is a major health care concern that currently lacks any effective treatment. Despite promising outcomes from many preclinical studies, clinical evaluations have failed to identify effective pharmacological therapies, suggesting that the translational potential of preclinical models may require improvement. Rodents continue to be the most widely used species for preclinical TBI research. As most human TBIs result from impact to an intact skull, closed head injury (CHI) models are highly relevant, however, traditional CHI models suffer from extensive experimental variability that may be due to poor control over biomechanical inputs. Here we describe a novel CHI model called CHIMERA (Closed-Head Impact Model of Engineered Rotational Acceleration) that fully integrates biomechanical, behavioral, and neuropathological analyses. CHIMERA is distinct from existing neurotrauma model systems in that it uses a completely non-surgical procedure to precisely deliver impacts of prescribed dynamic characteristics to a closed skull while enabling kinematic analysis of unconstrained head movement. In this study, we characterized head kinematics as well as functional, neuropathological, and biochemical outcomes up to 14d following repeated TBI (rTBI) in adult C57BL/6 mice using CHIMERA. RESULTS: Head kinematic analysis showed excellent repeatability over two closed head impacts separated at 24h. Injured mice showed significantly prolonged loss of righting reflex and displayed neurological, motor, and cognitive deficits along with anxiety-like behavior. Repeated TBI led to diffuse axonal injury with extensive microgliosis in white matter from 2-14d post-rTBI. Injured mouse brains also showed significantly increased levels of TNF-α and IL-1ß and increased endogenous tau phosphorylation. CONCLUSIONS: Repeated TBI using CHIMERA mimics many of the functional and pathological characteristics of human TBI with a reliable biomechanical response of the head. This makes CHIMERA well suited to investigate the pathophysiology of TBI and for drug development programs.

Intravenously injected human apolipoprotein A-I rapidly enters the central nervous system via the choroid plexus.

BACKGROUND: Brain lipoprotein metabolism is dependent on lipoprotein particles that resemble plasma high-density lipoproteins but that contain apolipoprotein (apo) E rather than apoA-I as their primary protein component. Astrocytes and microglia secrete apoE but not apoA-I; however, apoA-I is detectable in both cerebrospinal fluid and brain tissue lysates. The route by which plasma apoA-I enters the central nervous system is unknown. METHODS AND RESULTS: Steady-state levels of murine apoA-I in cerebrospinal fluid and interstitial fluid are 0.664 and 0.120 µg/mL, respectively, whereas brain tissue apoA-I is ≈10% to 15% of its levels in liver. Recombinant, fluorescently tagged human apoA-I injected intravenously into mice localizes to the choroid plexus within 30 minutes and accumulates in a saturable, dose-dependent manner in the brain. Recombinant, fluorescently tagged human apoA-I accumulates in the brain for 2 hours, after which it is eliminated with a half-life of 10.3 hours. In vitro, human apoA-I is specifically bound, internalized, and transported across confluent monolayers of primary human choroid plexus epithelial cells and brain microvascular endothelial cells. CONCLUSIONS: Following intravenous injection, recombinant human apoA-I rapidly localizes predominantly to the choroid plexus. Because apoA-I mRNA is undetectable in murine brain, our results suggest that plasma apoA-I, which is secreted from the liver and intestine, gains access to the central nervous system primarily by crossing the blood-cerebrospinal fluid barrier via specific cellular mediated transport, although transport across the blood-brain barrier may also contribute to a lesser extent.

Living-engineered valves for transcatheter venous valve repair.

BACKGROUND: Chronic venous insufficiency (CVI) represents a major global health problem with increasing prevalence and morbidity. CVI is due to an incompetence of the venous valves, which causes venous reflux and distal venous hypertension. Several studies have focused on the replacement of diseased venous valves using xeno- and allogenic transplants, so far with moderate success due to immunologic and thromboembolic complications. Autologous cell-derived tissue-engineered venous valves (TEVVs) based on fully biodegradable scaffolds could overcome these limitations by providing non-immunogenic, non-thrombogenic constructs with remodeling and growth potential. METHODS: Tri- and bicuspid venous valves (n=27) based on polyglycolic acid-poly-4-hydroxybutyrate composite scaffolds, integrated into self-expandable nitinol stents, were engineered from autologous ovine bone-marrow-derived mesenchymal stem cells (BM-MSCs) and endothelialized. After in vitro conditioning in a (flow) pulse duplicator system, the TEVVs were crimped (n=18) and experimentally delivered (n=7). The effects of crimping on the tissue-engineered constructs were investigated using histology, immunohistochemistry, scanning electron microscopy, grating interferometry (GI), and planar fluorescence reflectance imaging. RESULTS: The generated TEVVs showed layered tissue formation with increasing collagen and glycosaminoglycan levels dependent on the duration of in vitro conditioning. After crimping no effects were found on the MSC level in scanning electron microscopy analysis, GI, histology, and extracellular matrix analysis. However, substantial endothelial cell loss was detected after the crimping procedure, which could be reduced by increasing the static conditioning phase. CONCLUSIONS: Autologous living small-diameter TEVVs can be successfully fabricated from ovine BM-MSCs using a (flow) pulse duplicator conditioning approach. These constructs hold the potential to overcome the limitations of currently used non-autologous replacement materials and may open new therapeutic concepts for the treatment of CVI in the future.

A three-dimensional engineered artery model for in vitro atherosclerosis research.

The pathogenesis of atherosclerosis involves dysfunctions of vascular endothelial cells and smooth muscle cells as well as blood borne inflammatory cells such as monocyte-derived macrophages. In vitro experiments towards a better understanding of these dysfunctions are typically performed in two-dimensional cell culture systems. However, these models lack both the three-dimensional structure and the physiological pulsatile flow conditions of native arteries. We here describe the development and initial characterization of a tissue engineered artery equivalent, which is composed of human primary endothelial and smooth muscle cells and is exposed to flow in vitro. Histological analyses showed formation of a dense tissue composed of a tight monolayer of endothelial cells supported by a basement membrane and multiple smooth muscle cell layers. Both low (LDL) and high density lipoproteins (HDL) perfused through the artery equivalent were recovered both within endothelial cells and in the sub-endothelial intima. After activation of the endothelium with either tumour necrosis factor alpha (TNFα) or LDL, monocytes circulated through the model were found to adhere to the activated endothelium and to transmigrate into the intima. In conclusion, the described tissue engineered human artery equivalent model represents a significant step towards a relevant in vitro platform for the systematic assessment of pathogenic processes in atherosclerosis independently of any systemic factors.

Interleukin 6 stimulates endothelial binding and transport of high-density lipoprotein through induction of endothelial lipase.

OBJECTIVE: In the reverse cholesterol transport pathway, high-density lipoprotein (HDL) passes the endothelial cell barrier by mechanisms involving the scavenger receptor class B type I and the ATP-binding cassette G1. However, little is known on how inflammation influences this transendothelial transport. APPROACH AND RESULTS: On stimulation with interleukin-6, cultivated primary endothelial cells showed increased binding and transport of (125)I-HDL without changing the expression of scavenger receptor class B type I and ATP-binding cassette G1. Therefore, we analyzed the involvement of endothelial lipase (EL), a known HDL-binding protein expressed by endothelial cells. Here, we show an increased EL expression after interleukin-6 stimulation. Moreover, using pharmacological inhibitors or RNA interference against EL, we demonstrated its participation in HDL binding and transport through the endothelium. Furthermore, adenovirus-mediated transfection of endothelial cells with either catalytically active or nonactive EL revealed that EL facilitates the endothelial binding and transport by both bridging and lipolysis of HDL. EL was also found responsible for the reduction of HDL particle size occurring during the specific transport through a monolayer of endothelial cells. Finally, pharmacological inhibition of EL reversed the inducing effect of interleukin-6 on HDL binding and transport. CONCLUSIONS: Interleukin-6 stimulates the translocation of HDL through the endothelium, the first step in reverse cholesterol transport pathway, by enhancing EL expression. In addition, we demonstrated the role of EL in the transendothelial transport of HDL.

An intervention programme for the management of multidrug-resistant tuberculosis in France.

As shown in a previous study, the outcome of multidrug-resistant tuberculosis (MDR-TB) in France is not satisfactory (41% success rate). To improve the management and outcome of patients with MDR-TB, a prospective intervention study was carried out in 1998-1999 by National Reference Centre (NRC) staff. NRC staff contacted (i) the microbiologists reporting MDR-TB patients in order to offer second-line drug testing and (ii) physicians to help tailor treatment regimens based on World Health Organization guidelines. A total of 45 MDR-TB patients were followed, including 33 for whom NRC staff successfully interacted with the physicians in charge and 12 patients managed without NRC collaboration. The crude proportion of favourable outcomes was 58%, and this proportion reached 70% for patients managed in collaboration with the NRC. Among the latter 33 patients, 32 were treated with at least three active drugs for a median duration of 12 months. In multivariate analysis, HIV-positive status was associated with treatment failure (hazard ratio (HR) 4.3), whereas NRC intervention was associated with a favourable outcome (HR 0.2). However, even in the NRC intervention group the median duration of treatment was shorter than planned (median 12 months) and 12% of patients were lost to follow-up. This intervention study provides encouraging results and should be continued until reference teams and a directly observed treatment strategy (DOTS) are implemented to improve patient management further.