Body stiffness is a mechanical property that facilitates contact-mediated mate recognition in Caenorhabditis elegans

Physical contact is prevalent in the animal kingdom to recognize suitable mates by decoding information about sex, species, and maturity. Although chemical cues for mate recognition have been extensively studied, the role of mechanical cues remains elusive. Here, we show that C. elegans males recognize conspecific and reproductive mates through short-range cues, and that the attractiveness of potential mates depends on the sex and developmental stages of the hypodermis. We find that a particular group of cuticular collagens is required for mate attractiveness. These collagens maintain body stiffness to sustain mate attractiveness but do not affect the surface properties that evoke the initial step of mate recognition, suggesting that males utilize multiple sensory mechanisms to recognize suitable mates. Manipulations of body stiffness via physical interventions, chemical treatments, and 3D-printed bionic worms indicate that body stiffness is a mechanical property for mate recognition and increases mating efficiency. Our study thus extends the repertoire of sensory cues of mate recognition in C. elegans and provides a paradigm to study the important roles of mechanosensory cues in social behaviors.

Pathogen metabolite checkpoint: NHR on guard

How can beneficial microorganisms be distinguished from pathogenic ones? In this issue of Immunity, Peterson et al. discovered that a specific phenazine, which is part of a family of toxic metabolites expressed by pathogenic bacteria, is detected by Caenorhabditis elegans by directly binding to a nuclear hormone receptor, promoting the expression of detoxifying enzymes and immunity-related genes, thus protecting the worm.

Meisosomes, folded membrane microdomains between the apical extracellular matrix and epidermis

Apical extracellular matrices (aECMs) form a physical barrier to the environment. In Caenorhabditis elegans, the epidermal aECM, the cuticle, is composed mainly of different types of collagen, associated in circumferential ridges separated by furrows. Here, we show that in mutants lacking furrows, the normal intimate connection between the epidermis and the cuticle is lost, specifically at the lateral epidermis, where, in contrast to the dorsal and ventral epidermis, there are no hemidesmosomes. At the ultrastructural level, there is a profound alteration of structures that we term 'meisosomes,' in reference to eisosomes in yeast. We show that meisosomes are composed of stacked parallel folds of the epidermal plasma membrane, alternately filled with cuticle. We propose that just as hemidesmosomes connect the dorsal and ventral epidermis, above the muscles, to the cuticle, meisosomes connect the lateral epidermis to it. Moreover, furrow mutants present marked modifications of the biomechanical properties of their skin and exhibit a constitutive damage response in the epidermis. As meisosomes co-localise to macrodomains enriched in phosphatidylinositol (4,5) bisphosphate, they could conceivably act, like eisosomes, as signalling platforms, to relay tensile information from the aECM to the underlying epidermis, as part of an integrated stress response to damage.

Survey of practices in surgical management of trapeziometacarpal osteoarthritis in France in 2020

The purpose of this study was to obtain an overview of French surgical practices for treating trapeziometacarpal osteoarthritis in 2020. An online survey was sent to 64 French hand surgeons: 32 authors of articles on carpometacarpal osteoarthritis of the thumb and 32 other surgeons randomly selected from the membership of the French Society of Hand Surgery (SFCM). The questions concerned demographic data, surgical practice, operative indications, choices for revision surgery, and eight clinical cases. The response rate was 56.2%. The most popular technique was trapeziometacarpal replacement (63.9%). During the previous 5 years, 31.6% of respondents had changed their practices, 69.2% of whom had adopted total joint replacement. Total trapeziectomy with ligamentoplasty and interposition was the second most frequent method. Most surgeons (77.8%) implemented medical treatment for 6 months to 1 year before resorting to surgery. In the clinical cases, agreement between surgeons was very low, with an overall inter-rater concordance coefficient of 0.182. Except for two cases (a young manual worker and a patient with a flattened trapezium) where no technique was significantly preferred, trapeziometacarpal replacement was chosen by a majority of respondents (p < 0.001). It was the most frequently performed surgical technique in France in 2020. However, there is no real consensus on choice of technique, which reflects the absence of guidelines.

ATFS-1 plays no repressive role in the regulation of epidermal immune response

Fungal infection triggers the induction of antimicrobial peptide (AMP) genes in the epidermis (Pujol et al, 2008). We previously showed that this effect is suppressed by the mitochondrial unfolded protein response (UPR^mt), which can be activated by knockdown of select genes including the mitochondrial metalloprotease spg-7 (Zugasti et al, 2016). Here, we confirm that RNAi against spg-7 triggers the UPR^mt and blocks AMP induction during infection, whereas infection itself does not trigger the UPR^mt. ATFS-1 is a key factor in the UPR^mt, mediating much of the associated transcriptional response. We find that, surprisingly, ATFS-1 is not required for the suppression of AMP induction provoked by spg-7(RNAi). These data show that the mitochondrial dysfunction that blocks the immune response upon infection or wounding is independent of ATFS-1.

C. elegans: out on an evolutionary limb

The natural environment of the free-living nematode Caenorhabditis elegans is rich in pathogenic microbes. There is now ample evidence to indicate that these pathogens exert a strong selection pressure on C. elegans, and have shaped its genome, physiology, and behaviour. In this short review, we concentrate on how C. elegans stands out from other animals in terms of its immune repertoire and innate immune signalling pathways. We discuss how C. elegans often detects pathogens because of their effects on essential cellular processes, or organelle integrity, in addition to direct microbial recognition. We illustrate the extensive molecular plasticity that is characteristic of immune defences in C. elegans and highlight some remarkable instances of lineage-specific innovation in innate immune mechanisms.

Antagonistic fungal enterotoxins intersect at multiple levels with host innate immune defences

Animals and plants need to defend themselves from pathogen attack. Their defences drive innovation in virulence mechanisms, leading to never-ending cycles of co-evolution in both hosts and pathogens. A full understanding of host immunity therefore requires examination of pathogen virulence strategies. Here, we take advantage of the well-studied innate immune system of Caenorhabditis elegans to dissect the action of two virulence factors from its natural fungal pathogen Drechmeria coniospora. We show that these two enterotoxins have strikingly different effects when expressed individually in the nematode epidermis. One is able to interfere with diverse aspects of host cell biology, altering vesicle trafficking and preventing the key STAT-like transcription factor STA-2 from activating defensive antimicrobial peptide gene expression. The second increases STA-2 levels in the nucleus, modifies the nucleolus, and, potentially as a consequence of a host surveillance mechanism, causes increased defence gene expression. Our results highlight the remarkably complex and potentially antagonistic mechanisms that come into play in the interaction between co-evolved hosts and pathogens.

ifas-1 is upregulated by fungal infection in a GPA-12 and STA-2-independent manner in the Caenorhabditis elegans epidermis

Skin infection with the fungus Drechmeria coniospora leads to a transcriptional response in the worm epidermis. This involves an increased expression of a group of antimicrobial peptide (AMP) genes including those in the nlp-29 and cnc-2 clusters. The major pathways leading to the expression of these AMP genes have been well characterized and converge on the STAT transcription factor STA-2. We reported previously that expression in the epidermis of a constitutively active (gain of function, gf) form of the Gα protein GPA-12 (GPA-12gf) recapitulates much of the response to infection. To reveal parallel pathways activated by infection, we focus here on an effector gene that is not induced by GPA-12gf. This gene, ifas-1, encodes a protein with a fascin domain, associated with actin binding. Its induction upon fungal infection does not require sta-2. A transcriptional reporter revealed induction in the epidermis of ifas-1 by infection and wounding. Thus, ifas-1 represents part of a previously unexplored aspect of the innate immune response to infection.

Innate immunity in C. elegans

In its natural habitat, C. elegans encounters a wide variety of microbes, including food, commensals and pathogens. To be able to survive long enough to reproduce, C. elegans has developed a complex array of responses to pathogens. These activities are coordinated on scales that range from individual organelles to the entire organism. Often, the response is triggered within cells, by detection of infection-induced damage, mainly in the intestine or epidermis. C. elegans has, however, a capacity for cell non-autonomous regulation of these responses. This frequently involves the nervous system, integrating pathogen recognition, altering host biology and governing avoidance behavior. Although there are significant differences with the immune system of mammals, some mechanisms used to limit pathogenesis show remarkable phylogenetic conservation. The past 20 years have witnessed an explosion of host-pathogen interaction studies using C. elegans as a model. This review will discuss the broad themes that have emerged and highlight areas that remain to be fully explored.

Comparison of lipidome profiles of Caenorhabditis elegans-results from an inter-laboratory ring trial

INTRODUCTION

Lipidomic profiling allows 100s if not 1000s of lipids in a sample to be detected and quantified. Modern lipidomics techniques are ultra-sensitive assays that enable the discovery of novel biomarkers in a variety of fields and provide new insight in mechanistic investigations. Despite much progress in lipidomics, there remains, as for all high throughput "omics" strategies, the need to develop strategies to standardize and integrate quality control into studies in order to enhance robustness, reproducibility, and usability of studies within specific fields and beyond.

OBJECTIVES

We aimed to understand how much results from lipid profiling in the model organism Caenorhabditis elegans are influenced by different culture conditions in different laboratories.

METHODS

In this work we have undertaken an inter-laboratory study, comparing the lipid profiles of N2 wild type C. elegans and daf-2(e1370) mutants lacking a functional insulin receptor. Sample were collected from worms grown in four separate laboratories under standardized growth conditions. We used an UPLC-UHR-ToF-MS system allowing chromatographic separation before MS analysis.

RESULTS

We found common qualitative changes in several marker lipids in samples from the individual laboratories. On the other hand, even in this controlled experimental system, the exact fold-changes for each marker varied between laboratories.

CONCLUSION

Our results thus reveal a serious limitation to the reproducibility of current lipid profiling experiments and reveal challenges to the integration of such data from different laboratories.

Innate Immunity Promotes Sleep through Epidermal Antimicrobial Peptides

Wounding and infection trigger a protective innate immune response that includes the production of antimicrobial peptides in the affected tissue as well as increased sleep. Little is known, however, how peripheral wounds or innate immunity signal to the nervous system to increase sleep. We found that, during C. elegans larval molting, an epidermal tolloid/bone morphogenic protein (BMP)-1-like protein called NAS-38 promotes sleep. NAS-38 is negatively regulated by its thrombospondin domain and acts through its astacin protease domain to activate p38 mitogen-activated protein (MAP)/PMK-1 kinase and transforming growth factor β (TGF-β)-SMAD/SMA-3-dependent innate immune pathways in the epidermis that cause STAT/STA-2 and SLC6 (solute carrier)/SNF-12-dependent expression of antimicrobial peptide (AMP) genes. We show that more than a dozen epidermal AMPs act as somnogens, signaling across tissues to promote sleep through the sleep-active RIS neuron. In the adult, epidermal injury activates innate immunity and turns up AMP production to trigger sleep, a process that requires epidermal growth factor receptor (EGFR) signaling that is known to promote sleep following cellular stress. We show for one AMP, neuropeptide-like protein (NLP)-29, that it acts through the neuropeptide receptor NPR-12 in locomotion-controlling neurons that are presynaptic to RIS and that depolarize this neuron to induce sleep. Sleep in turn increases the chance of surviving injury. Thus, we found a novel mechanism by which peripheral wounds signal to the nervous system to increase protective sleep. Such a cross-tissue somnogen-signaling function of AMPs might also boost sleep in other animals, including humans.

unc-119 mutants have an increased fungal spore adhesion that is not rescued by Cb-unc-119

If the cuticle acts as a protective barrier against environmental insults, several pathogens have developed strategies that use it as a way to infect C. elegans. The fungus Drechmeria coniospora produces spores that attach to the cuticle, before hyphae invade the body. Mutants with an altered surface coat, the outermost layer of the cuticle, including bus-2, bus-4, bus-12 and bus-17 show increased adhesion of fungal spores (Rouger et al, 2014; Zugasti et al, 2016). We unexpectedly found that D. coniospora spores attach unusually densely around the mouth of unc-119 mutants. Interestingly, this phenotype is not rescued by the C. briggsaeunc-119 construct that is conventionally used to rescue neuronal unc-119 phenotypes.

Microtubule plus-end dynamics link wound repair to the innate immune response

The skin protects animals from infection and physical damage. In Caenorhabditis elegans, wounding the epidermis triggers an immune reaction and a repair response, but it is not clear how these are coordinated. Previous work implicated the microtubule cytoskeleton in the maintenance of epidermal integrity (Chuang et al., 2016). Here, by establishing a simple wounding system, we show that wounding provokes a reorganisation of plasma membrane subdomains. This is followed by recruitment of the microtubule plus end-binding protein EB1/EBP-2 around the wound and actin ring formation, dependent on ARP2/3 branched actin polymerisation. We show that microtubule dynamics are required for the recruitment and closure of the actin ring, and for the trafficking of the key signalling protein SLC6/SNF-12 toward the injury site. Without SNF-12 recruitment, there is an abrogation of the immune response. Our results suggest that microtubule dynamics coordinate the cytoskeletal changes required for wound repair and the concomitant activation of innate immunity.

An Antimicrobial Peptide and Its Neuronal Receptor Regulate Dendrite Degeneration in Aging and Infection

Infections have been identified as possible risk factors for aging-related neurodegenerative diseases, but it remains unclear whether infection-related immune molecules have a causative role in neurodegeneration during aging. Here, we reveal an unexpected role of an epidermally expressed antimicrobial peptide, NLP-29 (neuropeptide-like protein 29), in triggering aging-associated dendrite degeneration in C. elegans. The age-dependent increase of nlp-29 expression is regulated by the epidermal tir-1/SARM-pmk-1/p38 MAPK innate immunity pathway. We further identify an orphan G protein-coupled receptor NPR-12 (neuropeptide receptor 12) acting in neurons as a receptor for NLP-29 and demonstrate that the autophagic machinery is involved cell autonomously downstream of NPR-12 to transduce degeneration signals. Finally, we show that fungal infections cause dendrite degeneration using a similar mechanism as in aging, through NLP-29, NPR-12, and autophagy. Our findings reveal an important causative role of antimicrobial peptides, their neuronal receptors, and the autophagy pathway in aging- and infection-associated dendrite degeneration.

A model of guided cell self-organization for rapid and spontaneous formation of functional vessels

Most achievements to engineer blood vessels are based on multiple-step manipulations such as manual sheet rolling or sequential cell seeding followed by scaffold degradation. Here, we propose a one-step strategy using a microfluidic coextrusion device to produce mature functional blood vessels. A hollow alginate hydrogel tube is internally coated with extracellular matrix to direct the self-assembly of a mixture of endothelial cells (ECs) and smooth muscle cells (SMCs). The resulting vascular structure has the correct configuration of lumen, an inner lining of ECs, and outer sheath of SMCs. These "vesseloids" reach homeostasis within a day and exhibit the following properties expected for functional vessels (i) quiescence, (ii) perfusability, and (iii) contractility in response to vasoconstrictor agents. Together, these findings provide an original and simple strategy to generate functional artificial vessels and pave the way for further developments in vascular graft and tissue engineering and for deciphering the angiogenesis process.

Neither significant osteoarthritic changes nor deteriorating subjective outcomes occur after hybrid fixation of osteochondritis dissecans in the young adult

PURPOSE

The goal of the fixation of painful osteochondritis dissecans of the femoral condyles in adults is to integrate the osteochondral fragment and thus achieve a normal hyaline cartilaginous coverage. The addition of a biological process to primary fixation may result in improved fragment integration (hybrid fixation). Osteochondral plugs may fulfil this role. The aim of this study was to evaluate long-term clinical and radiological results after hybrid fixation of unstable osteochondritis dissecans. The hypothesis was that the rate of secondary osteoarthritis would be low.

METHODS

Nine patients treated by hybrid fixation were retrospectively reviewed at a median follow-up of 10.1 years (range 7-14). The median age at surgery was 21 (range 17-28). Six of them were evaluated as ICRS grade II and three, as ICRS grade III. The mean surface of the lesion was 4.5 cm². All patients were followed up clinically (IKDC, KOOS, Lysholm) and radiologically [Kellgren-Lawrence score (KL)].

RESULTS

During arthroscopic assessment at the time of screw removal (3 months after surgery), the fragments were stable, and autograft plugs were all well integrated. At the most recent follow-up visit, the median IKDC score was 85.8 (range 51.72-100), the KOOS score was 87.7 (52.4-100), and the Lysholm scale score was 89.8 (77-100). In 7 out of 9 patients, radiographs showed a joint space KL grade of 0 or 1.

CONCLUSION

Hybrid fixation for treating osteochondritis dissecans lesions of the femoral condyles using mechanical and biological fixation provides healing of the osteochondral fragments with good long-term outcomes. No significant osteoarthritic change was seen with this technique at a mid-term follow-up.

LEVEL OF EVIDENCE

IV-case series.

Experimental study of the susceptibility of a European Aedes albopictus strain to dengue virus under a simulated Mediterranean temperature regime

Dengue virus (DENV) has re-emerged in Europe driven by the geographic expansion of the mosquito species Aedes albopictus and Aedes aegypti (Diptera: Culicidae) and the introduction of the virus by viraemic travellers. In the present study, the vector competence (VC) of Ae. albopictus collected in Catalonia (northeast Spain) was evaluated for two different DENV strains, DENV-1 and DENV-2, the serotypes responsible for all outbreaks of dengue that have occurred in Europe. Mosquitoes were reared under environmental conditions mimicking the mean temperature and humidity recorded in July on the Mediterranean coast of Catalonia. Mosquitoes were fed on an artificial infectious bloodmeal and, at 14 days post-exposure, infection, disseminated infection and transmission rates (IR, DIR, TR) and transmission efficiency (TE) were determined by testing the virus in the body, legs and saliva. The tested Ae. albopictus strain was found to be susceptible to both DENV-1 and DENV-2 and to be able to transmit DENV-1. This is the first time that the VC of Ae. albopictus for DENV has been tested in Europe in this specific context (i.e. mimicking the Mediterranean temperature and humidity recorded in Catalonia in July). This study confirms the potential of Ae. albopictus to start autochthonous DENV transmission cycles in the Mediterranean basin.

Complications and cost of single-stage vs. two-stage bilateral unicompartmental knee arthroplasty: A case-control study

BACKGROUND

Single-stage bilateral knee arthroplasty, even when unicompartmental, remains controversial, chiefly due to the risk of peri-operative complications. The primary objective of this study was to compare the short-term complication rate and cost of single- vs. two-stage bilateral unicompartmental knee arthroplasty (UCA). The secondary objective was to compare total hospital stay lengths and motion-range recovery.

HYPOTHESIS

Single-stage bilateral UCA is a cost-saving alternative that is not associated with higher complication rates compared to two-stage bilateral UCA.

MATERIAL AND METHOD

This single-centre retrospective comparative study included 70 patients of any age managed between 2010 and 2016. Among them, 44 (88 UKAs) had single-stage surgery (1S group) and 26 (52 UCAs) two-stage surgery (2S group). The two groups were comparable for age, body mass index, gender distribution, compartment replaced, ASA score, and Charlson comorbidity index. The following were evaluated: operative time, haemoglobin level before and after surgery, major and minor complication rates, motion-range recovery, and the radiographic hip-knee-ankle (HKA) angle. Costs were estimated based on the standard codes assigned to the procedures by the national statutory health insurance system (GHM 08C24 for knee arthroplasty to treat knee osteoarthritis and NFKA006 for unicompartmental tibio-femoral or femoro-patellar arthroplasty), modulated according to the concomitant diagnoses.

RESULTS

No differences were found for the haemoglobin level change, time to motion-range recovery, or HKA angle. The complication rates per patient were not significantly different between the groups: major complications, 9.1% (n=4) in the 1S group and 15.4% (n=4) in the 2S group (p=1.00); minor complications, 4.5% (n=2) in the 1S group and 3.8% (n=1) in the 2S group (p=1.00). Cost of the total hospital stay was significantly higher in the 2S group than in the 1S group (11,766.7€) and 5626.4€, respectively; p<0.001). Mean total hospital stay duration per patient was 6.7 days with single-stage surgery and 13.4 days with two-stage surgery.

DISCUSSION

Single-stage bilateral UCA is not associated with a higher rate of peri-operative complications compared to the two-stage alternative and is substantially less costly. Financial incentives from the healthcare authorities are warranted to increase the use of the single-stage procedure.

LEVEL OF EVIDENCE

III, case-control study.

Meniscal sizing before allograft: Comparison of three imaging techniques

BACKGROUND

Accuracy of meniscal sizing is an important issue before allograft transplantation. To date, there is no consensus on the best imaging method. The purpose of this study was to compare plain radiographs, magnetic resonance imaging (MRI) and computed tomography (CT) arthrography in the assessment of meniscal size. We hypothesized that MRI and CT arthrography had better correlations than plain radiographs.

METHODS

All patients operated on by meniscal allograft between January 2005 and May 2015 were screened. Among them, 32 patients had both preoperative radiographs, MRI and CT arthrography of the affected knee. The meniscal dimensions were evaluated, blindly and randomly, using three imaging methods. A correlation analysis between each technique was made. For radiographic methods, an additional comparison was made between original Pollard's method and the modified method (Yoon). Bone dimensions (tibial metaphysis) were also collected, using radiographs and MRI, in order to build new equations allowing determination of meniscal dimensions from those bone measurements.

RESULTS

The radiographic methods offered satisfying evaluations of the meniscal dimensions in the sagittal plane, without significant difference when compared with CT arthrography or MRI. In the frontal plane, the radiograph methods were less effective. With new equations, allowing determination of meniscal dimensions from tibial plateau dimensions, the mean correlation coefficient was 0.39 (0.14-0.71).

CONCLUSIONS

The correlation between radiographic methods and MRI depended on which parameter (frontal or sagittal) was measured. Thus, we proposed a new method for sizing of meniscus, easily measurable from bony landmarks, aiming to improve the accuracy of graft selection.

Modulatory upregulation of an insulin peptide gene by different pathogens in C. elegans

When an animal is infected, its innate immune response needs to be tightly regulated across tissues and coordinated with other aspects of organismal physiology. Previous studies with Caenorhabditis elegans have demonstrated that insulin-like peptide genes are differentially expressed in response to different pathogens. They represent prime candidates for conveying signals between tissues upon infection. Here, we focused on one such gene, ins-11 and its potential role in mediating cross-tissue regulation of innate immune genes. While diverse bacterial intestinal infections can trigger the up-regulation of ins-11 in the intestine, we show that epidermal infection with the fungus Drechmeria coniospora triggers an upregulation of ins-11 in the epidermis. Using the Shigella virulence factor OpsF, a MAP kinase inhibitor, we found that in both cases, ins-11 expression is controlled cell autonomously by p38 MAPK, but via distinct transcription factors, STA-2/STAT in the epidermis and HLH-30/TFEB in the intestine. We established that ins-11, and the insulin signaling pathway more generally, are not involved in the regulation of antimicrobial peptide gene expression in the epidermis. The up-regulation of ins-11 in the epidermis does, however, affect intestinal gene expression in a complex manner, and has a deleterious effect on longevity. These results support a model in which insulin signaling, via ins-11, contributes to the coordination of the organismal response to infection, influencing the allocation of resources in an infected animal.

Evolutionary plasticity in the innate immune function of Akirin

Eukaryotic gene expression requires the coordinated action of transcription factors, chromatin remodelling complexes and RNA polymerase. The conserved nuclear protein Akirin plays a central role in immune gene expression in insects and mammals, linking the SWI/SNF chromatin-remodelling complex with the transcription factor NFκB. Although nematodes lack NFκB, Akirin is also indispensable for the expression of defence genes in the epidermis of Caenorhabditis elegans following natural fungal infection. Through a combination of reverse genetics and biochemistry, we discovered that in C. elegans Akirin has conserved its role of bridging chromatin-remodellers and transcription factors, but that the identity of its functional partners is different since it forms a physical complex with NuRD proteins and the POU-class transcription factor CEH-18. In addition to providing a substantial step forward in our understanding of innate immune gene regulation in C. elegans, our results give insight into the molecular evolution of lineage-specific signalling pathways.

Opening-wedge high tibial osteotomy without bone grafting in severe varus osteoarthritic knee. Rate and risk factors of non-union in 41 cases

INTRODUCTION

Using locking plates in opening-wedge high tibial osteotomy (OWHTO) via a medial opening theoretically allows early weight-bearing without need for bone or bone-substitute grafting. It incurs a risk of non-consolidation in case of large correction (>10°), although rates and risk factors of non-union are not known. The present retrospective study compared OWHTO with correction <10° versus >10°, with a view to determining: (1) complications rates (non-union) according to degree of correction, and (2) risk factors for such complications.

HYPOTHESIS

OWHTO with correction greater than 10° without graft shows normal consolidation and allows early weight-bearing.

MATERIAL AND METHOD

Forty-one patients treated by OWHTO for medial osteoarthritis of the knee between January 2101 and November 2015 were included in a retrospective study. HKA angle was assessed by long-leg axis radiographs, preoperatively and at 3 months. Clinical and radiological follow-up at 6 weeks, 3 months and 6 months assessed consolidation in terms of >40% filling of the osteotomy site. Partial (contact) weight-bearing was allowed from the first postoperative day, with full weight-bearing at 6 weeks.

RESULTS

Mean patient age was 59±5 years. Mean body-mass index (BMI) was 30.3±5.2; 17 patients (41.5%) had BMI >30. Mean initial HKA angle was 173.5°±3° (range, 167-178°) and mean correction was 10.7°±2.7° (range, 5-15°). There were 27 corrections of 10° or more, and 14 less than 10°. At 3 months, mean HKA was 182.9°±2.5° (range, 178-187°). Twelve cases showed lateral tibial cortex fracture after opening. Thirty-six patients (87.8%) showed consolidation, at a mean 5±3 months. Five patients showed osteotomy site non-union; in all these cases, the lateral cortex was broken initially (P=0.003); all had BMI >30 (mean, 37.2±3.8; P<0.03); none were smokers. On univariate analysis, lateral tibial cortex fracture (OR=10; 95% CI, (1.59-196.30)), BMI >30 (OR=1.18; 95% CI, (1.03-1.41)) and correction ≥10° (OR=10.50; 95% CI, (2.49-53.86)) were associated with delayed consolidation. On multivariate analysis, only degree of osteotomy was significantly associated with delayed consolidation (OR=11.51; 95% CI, (2.13-95.74)).

DISCUSSION/CONCLUSION

Obesity and initial lateral cortex fracture appeared as risk factors for non-consolidation of OWHTO with large correction. Systematic bone or bone-substitute grafting may therefore be considered in this population in case of >10° correction.

LEVEL OF EVIDENCE

IV, prospective cohort study.

Is distal femoral torsion the same in both of a patient's legs? Morphometric CT study

INTRODUCTION

The rotational position of the femoral component is a primary driver of success in total knee arthroplasty. However, distal femoral torsion (DFT) varies greatly between individuals. Measuring DFT preoperatively by CT in combination with computer-assisted surgery can significantly improve the rotational positioning of the femoral component. However, a preoperative CT scan is costly and exposes the patient to radiation. These are doubled when the patient is undergoing bilateral arthroplasty. The aim of this study was to determine the DFT in both knees of a patient undergoing bilateral arthroplasty. We hypothesized that DFT was symmetric between a patient's two knees and was independent of frontal alignment.

MATERIAL AND METHODS

In this retrospective study of TKA cases performed between December 2008 and March 2015, 82 patients (mean age 73years) who underwent two-stage bilateral TKA (164 knees) were included. A preoperative CT scan of each knee was performed to measure the DFT using the surgical posterior condylar angle (PCA) described by Yoshioka. Two observers performed the measurements twice each, to allow calculation of the intraclass and interclass correlation coefficients.

RESULTS

The mean PCA was 5.4° (±1.48) in the right knee and 5.4° (±1.45) in the left knee, with a left/right difference ranging from 0 to 2.2° (p=0.8). In the entire cohort, 84.6% of patients had a left/right difference of less than 1°. We found no significant differences in DFT in knees with large or small frontal deformity (deformity<10°, p=0.7; deformity>10°, p=0.5) or the presence of varus or valgus (p=0.9). The intraclass correlation coefficient was excellent (94%) and the interclass correlation coefficient was moderate to good (60% for left knees, 53% for right knees).

DISCUSSION

Based on CT scan measurements, the DFT in both knees of an arthritic patient is comparable and this measurement is reproducible. This means that a single, unilateral preoperative CT scan is sufficient for planning purposes.

LEVEL OF EVIDENCE

IV (retrospective cohort study).

Hybrid fixation in adult osteochondritis dissecans of the knee

Osteochondritis dissecans progresses to osteoarthritis if integration of the fragment is not obtained. The prognosis of osteochondritis dissecans is more severe in adults, as spontaneous integration due to physeal closure does not occur. Hybrid fixation consists in combining screw fixation of the fragment with mosaicplasty through the fragment to promote integration into the native condyle. We describe this technique with reference to 17 patients.

Revealing potential bridge vectors for BTV and SBV: a study on Culicoides blood feeding preferences in natural ecosystems in Spain

Several species of Culicoides (Diptera: Ceratopogonidae) are vectors of pathogens, such as the bluetongue (BTV) and Schmallenberg (SBV) viruses, which cause important diseases in domestic and wild ruminants. As wild ruminants can contribute to overwintering and epizootics of both diseases, knowledge of the host-feeding behaviour of Culicoides in natural ecosystems is important to better understand their epidemiology. Blood-engorged Culicoides females trapped in natural areas inhabited by different wild ruminant species were genetically analysed to identify host species. The origin of bloodmeals was identified in 114 females of 14 species of Culicoides. A total of 104 (91.1%) Culicoides fed on mammals and 10 (8.9%) on birds. The most abundant host identified was red deer (66.7%), followed by humans (13%) and fallow deer (6.1%). Eleven of the 14 species of Culicoides fed exclusively on mammalian hosts. Among them, five are mammalophilic species considered to be important BTV and/or SBV vectors. The results of the present study confirm that Culicoides imicola, Culicoides obsoletus, Culicoides scoticus, Culicoides pulicaris and Culicoides punctatus fed on wild ruminants, and therefore support the hypothesis that these species can act as bridge vectors by facilitating the circulation of pathogens between wild and domestic ruminant communities.

Schmallenberg virus detection in Culicoides biting midges in Spain: First laboratory evidence for highly efficient infection of Culicoides of the Obsoletus complex and Culicoides imicola

Since Schmallenberg disease was discovered in 2011, the disease rapidly spread across Europe. Culicoides biting midges have been implicated as putative Schmallenberg vectors in Europe. The detection of Schmallenberg virus (SBV) in field collected Culicoides was evaluated through retrospective (2011-2012) collections and captures performed in 2013. This study represents the first detection of SBV in field collected Culicoides in Spain. Infectious midges were detected at the foothills of Pyrenees, Aramunt, in the summer 2012. All the specimens infected with Schmallenberg were of the species Culicoides obsoletus s.s. confirming its putative vector status in Spain. Experimental infection on field collected Culicoides provided evidence of atypical high efficiency for SBV vector infection and transmission potential in local populations of Culicoides imicola and in Culicoides of the Obsoletus complex. However, captured individuals of C. imicola were more susceptible to SBV infection than C. obsoletus s.l. (p < .001), with an infection ratio of 0.94 and 0.63, respectively. In contrast, a Culicoides nubeculosus colony appeared to be refractory to SBV infection.

Meniscal repair: Technique

Meniscal repair aims to achieve meniscal healing, avoiding the adverse effects of meniscectomy. Longitudinal vertical tears in a vascularized area are the reference indication. The technique generally uses hybrid all-inside implants. The outside-in technique has other indications in more anterior tears. Healing has been demonstrated on CT-arthrography and arthroscopy. Specific techniques have been developed for other pathological situations. Posterior meniscosynovial lesions in a context of chronic anterior laxity are identified by exploration of the posterior compartment, and fixed by all-inside hook suture. Horizontal lesions in young athletes can be treated by open meniscal suture. Radial tears, when deep, can be repaired. Root tears, when traumatic, can be treated by transosseous pullout reinsertion.

Management of traumatic meniscal tear and degenerative meniscal lesions. Save the meniscus

Meniscectomy remains one of the most frequent orthopedic procedures, despite meniscal sparing having been advocated for several decades now. Incidence is excessive in the light of scientifically robust studies demonstrating the interest of meniscal repair or of nonoperative treatment for traumatic tear and of nonoperative treatment for degenerative meniscal lesions. It is high time that the paradigm shifted, in favor of meniscal preservation. In traumatic tear, and most particularly longitudinal vertical tear in vascularized zones, repair shows a high success rates in terms of recovery time, functional outcome and cartilage protection. Leaving the meniscus alone may be an option in asymptomatic lesions of the lateral meniscus during anterior cruciate ligament (ACL) reconstruction. Posterior ramp lesions (in associated ACL tear), traumatic root tears and radial lesions are also excellent indications for repair, although it has to be borne in mind that the natural history of these lesions is not completely understood and nonoperative treatment also may be considered. Degenerative meniscal lesions are frequently revealed by MRI in middle-aged or elderly subjects. They are closely related to tissue aging and thus probably to osteoarthritic processes. Meniscectomy was long considered the treatment of choice. All but 1 of the 8 recent randomized studies reported non-superiority of arthroscopy over nonoperative treatment, which should thus be the first-line choice, with arthroscopic meniscectomy reserved for cases of failure, or earlier in case of "considerable" mechanical symptoms. Horizontal cleavage in young athletes is a particular case, requiring meniscal repair, to avoid a meniscectomy, which would inevitably be extensive in a young active patient. More than ever, the take-home message is: save the meniscus!

Rift Valley fever virus and European mosquitoes: vector competence of Culex pipiens and Stegomyia albopicta (= Aedes albopictus)

Rift Valley fever (RVF) is a mosquito-borne disease caused by the Rift Valley fever virus (RVFV). Rift Valley fever affects a large number of species, including human, and has severe impact on public health and the economy, especially in African countries. The present study examined the vector competence of three different European mosquito species, Culex pipiens (Linnaeus, 1758) form molestus (Diptera: Culicidae), Culex pipiens hybrid form and Stegomyia albopicta (= Aedes albopictus) (Skuse, 1894) (Diptera: Culicidae). Mosquitoes were artificially fed with blood containing RVFV. Infection, disseminated infection and transmission efficiency were evaluated. This is the first study to assess the transmission efficiency of European mosquito species using a virulent RVFV strain. The virus disseminated in Cx. pipiens hybrid form and in S. albopicta. Moreover, infectious viral particles were isolated from saliva of both species, showing their RVFV transmission capacity. The presence of competent Cx. pipiens and S. albopicta in Spain indicates that an autochthonous outbreak of RVF may occur if the virus is introduced. These findings provide information that will help health authorities to set up efficient entomological surveillance and RVFV vector control programmes.

Anatomical knee postero-lateral corner reconstruction: The "Versailles" technique

Postero-lateral knee instability raises surgical challenges. Of the many available reconstruction techniques, few ensure anatomical reconstruction of the postero-lateral corner (PLC). The "Versailles" technique ensures the anatomical reconstruction of the three main PLC stabilisers (lateral collateral ligament, popliteus tendon, and popliteo-fibular ligament) by using either a hamstring autograft or a tendon allograft.

High failure rate of anterior cruciate ligament reconstruction with bimeniscal repair: A case-control study

BACKGROUND

Bimeniscal lesions are common in patients with anterior cruciate ligament (ACL) tears. However, bimeniscal repair is rarely performed during ACL reconstruction.

OBJECTIVE

To assess outcomes after ACL reconstruction with bimeniscal repair.

HYPOTHESIS

Bimeniscal lesions, even when repaired, are associated with poorer outcomes of ACL reconstruction.

MATERIAL AND METHODS

A retrospective case-control design was used. The cases were 15 patients who underwent ACL reconstruction, without procedures on any other ligaments, combined with bimeniscal repair, between May 2009 and May 2013 (3.2% of all ACL reconstructions during the study period). This group (2-Mc group) was matched on age, gender, body mass index, and time to surgery to 30 patients who underwent ACL reconstruction and had no meniscal lesions (0-Mc group) and to 30 patients who underwent ACL reconstruction and repair of the medial meniscus (1-Mc group). After a mean follow-up of 3.6 years, clinical outcomes were assessed based on the KOOS, Lysholm, and IKDC scores and knee laxity based on TELOS and GNRB measurements. The primary outcome measure was the rate of ACL re-rupture. Secondary outcome measures were functional outcomes and rate of delayed meniscectomy.

RESULTS

The ACL re-rupture rate was significantly higher in the 2-Mc group than in the 0-Mc and 1-Mc groups pooled (20%, vs. 1.7%; P=0.02). The functional scores showed no significant differences across groups. Post-operative differential laxity was significantly greater in the 2-Mc group (3.3mm by TELOS, P=0.02; and 2.5mm by GNRB, P=0.03) than in the 0-Mc and 1-Mc groups pooled. Delayed meniscectomy was performed in none of the 2-Mc group patients and in 2 of the 1-Mc group patients.

CONCLUSION

ACL reconstruction combined with bimeniscal repair is a rarely performed procedure. It is associated with a high ACL re-rupture rate and greater differential laxity. Meniscal outcomes of bimeniscal repair, in contrast, are good.

LEVEL OF EVIDENCE

III, matched case-control study.

Ligand activation induces different conformational changes in CXCR3 receptor isoforms as evidenced by plasmon waveguide resonance (PWR)

The chemokine receptor CXCR3 plays important roles in angiogenesis, inflammation and cancer. Activation studies and biological functions of CXCR3 are complex due to the presence of spliced isoforms. CXCR3-A is known as a pro-tumor receptor whereas CXCR3-B exhibits anti-tumor properties. Here, we focused on the conformational change of CXCR3-A and CXCR3-B after agonist or antagonist binding using Plasmon Waveguide Resonance (PWR). Agonist stimulation induced an anisotropic response with very distinct conformational changes for the two isoforms. The CXCR3 agonist bound CXCR3-A with higher affinity than CXCR3-B. Using various concentrations of SCH546738, a CXCR3 specific inhibitor, we demonstrated that low SCH546738 concentrations (≤1 nM) efficiently inhibited CXCR3-A but not CXCR3-B’s conformational change and activation. This was confirmed by both, biophysical and biological methods. Taken together, our study demonstrates differences in the behavior of CXCR3-A and CXCR3-B upon ligand activation and antagonist inhibition which may be of relevance for further studies aimed at specifically inhibiting the CXCR3A isoform.

Surgical repair of massive rotator cuff tendon tears: Autologous quadriceps tendon graft versus arthroscopic repair

INTRODUCTION

Massive rotator cuff tear repair results are variable. The main purpose of this study was to compare functional outcome between two procedures: open repair by autologous quadriceps-patella tendon patch, and arthroscopic suture. The study hypothesis was that there is no significant difference in results between the two techniques.

MATERIAL AND METHODS

A retrospective study included all patients younger than 70 years operated on from 1995 to 2013 for massive rotator cuff tear. Exclusion criteria comprised history of dislocation, fracture or surgery or osteoarthritis in the affected shoulder, and infra- and supra-spinatus fatty degeneration equal to or greater than stage 3. Two consecutive groups were distinguished: group 1, from 1995 to 2003, comprised 23 patients (24 shoulders; mean age, 55.8 years) treated by open repair using quadriceps tendon autograft; group 2, from 2003 to 2013, comprised 27 patients (29 shoulders: mean age, 60.3 years) treated by arthroscopic repair.

RESULTS

Preoperatively, mean Constant score was 42.9 in group 1 and 45.7 in group 2 (P=0.36), pain score 5.5/15 and 7.6/15 (P=0.08), strength 3.0kg and 2.4kg (P=0.30), and subacromial space 6.3 and 6.7mm (P=0.05), respectively. At respectively 58 and 55 months' mean follow-up, Constant score was 71.1 in group 1 and 71.8 in group 2 (P=0.086), pain 11.9/15 and 12.7/15 (P=0.76), gain in strength 1.4kg and 2.3kg (P=0.0006), and subacromial space 7.1mm and 6.3mm (P=0.29), respectively. The complications rate was 70% in group 1 and there were no specific complications in group 2.

CONCLUSION

Functional improvement was significant and comparable between the 2 groups. Quadriceps tendon harvesting was associated with high morbidity, but the technique increased subacromial space.

LEVEL OF EVIDENCE

IV, retrospective, single-center.

Coordinated inhibition of C/EBP by Tribbles in multiple tissues is essential for Caenorhabditis elegans development

Background

Tribbles proteins are conserved pseudokinases that function to control kinase signalling and transcription in diverse biological processes. Abnormal function in human Tribbles has been implicated in a number of diseases including leukaemia, metabolic syndromes and cardiovascular diseases. Caenorhabditis elegans Tribbles NIPI-3 was previously shown to activate host defense upon infection by promoting the conserved PMK-1/p38 mitogen-activated protein kinase (MAPK) signalling pathway. Despite the prominent role of Tribbles proteins in many species, our knowledge of their mechanism of action is fragmented, and the in vivo functional relevance of their interactions with other proteins remains largely unknown.

Results

Here, by characterizing nipi-3 null mutants, we show that nipi-3 is essential for larval development and viability. Through analyses of genetic suppressors of nipi-3 null mutant lethality, we show that NIPI-3 negatively controls PMK-1/p38 signalling via transcriptional repression of the C/EBP transcription factor CEBP-1. We identified CEBP-1’s transcriptional targets by ChIP-seq analyses and found them to be enriched in genes involved in development and stress responses. Unlike its cell-autonomous role in innate immunity, NIPI-3 is required in multiple tissues to control organismal development.

Conclusions

Together, our data uncover an unprecedented crosstalk involving multiple tissues, in which NIPI-3 acts as a master regulator to inhibit CEBP-1 and the PMK-1/p38 MAPK pathway. In doing so, it keeps innate immunity in check and ensures proper organismal development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12915-016-0320-z) contains supplementary material, which is available to authorized users.

Abnormal rate of intraoperative and postoperative implant positioning outliers using "MRI-based patient-specific" compared to "computer assisted" instrumentation in total knee replacement

PURPOSE

The aim of this study was to analyze first intraoperative alignment and reason to abandon the use of patient-specific instrumentation using intraoperative CAS measurement, secondly assess by postoperative CT analysis if CI, based on preoperative 3D-MRI data, improved postoperative component positioning (including femoral rotation) and lower limb alignment as compared with results obtained with CAS.

METHODS

In this randomized controlled trial, 80 consecutive patients scheduled to undergo TKA were enrolled. Eligible knees were randomized to the group of PSI-TKAs (n = 40) or to the group of CAS-TKAs (n = 40). In the CAS group, CAS determined and controlled cutting block positioning in each plane. In the PSI group, CAS allowed to measure adequacy of intraoperative alignment including femoral component rotation. At 3 months after surgery, implants position were measured and analyzed with full-weight bearing plain radiographs and CT scan.

RESULTS

Intraoperatively, there was a significant difference concerning Sagittal Femoral mechanical, Frontal tibial mechanical angle and tibial slope between the two groups (respectively p = 0.01, p = 0.02, p = 0.046). Custom instrumentation was abandoned intraoperatively in seven knees (17.5 %). Abnormal tibial cuts were responsible of the abandon in three out of seven cases, femoral cut in 1/7 and dual abnormalities in 3/7. Postoperatively, tibial slope outliers percentage was higher in the patient specific instrumentation group with six patients (18.18 %) versus one patient (2.5 %) in the CAS group (p = 0.041).

CONCLUSION

Patient specific instrumentation was associated with an important number of hazardous cut and a higher rate of outliers in our series and thus should be used with caution as related to. This study is the first to our acknowledgement to compare intra-operative ancillary and implant positioning of PSI-TKA and CAS-TKA. High rate of malposition are sustained by our findings, as such PSI-TKA should be used with caution, by surgeons capable to switch to conventional instrumentation intra-operatively.

LEVEL OF EVIDENCE

Randomized control trial, Level I.

Outcomes of arthroscopic lateral epicondylitis release: Should we treat earlier?

BACKGROUND

When managed conservatively, lateral epicondylitis often subsides only after considerable time, during which social and occupational activities are severely disrupted. If conservative management fails, a recently introduced option is arthroscopic release of the extensor carpi radialis brevis (ECRB). The primary objective of this study was to compare clinical outcomes of this procedure according to preoperative symptom duration.

HYPOTHESIS

Earlier arthroscopic release is associated with better functional outcomes.

MATERIAL AND METHOD

Consecutive patients with arthroscopically managed lateral epicondylitis were included in a retrospective study. Arthroscopy was performed only after at least 6 months of conservative treatment. The criteria to evaluate the clinical outcomes were the Nirschl and Quick-DASH scores, muscle strength, time to pain relief, and percentage of functional recovery.

RESULT

Thirty-five patients were evaluated at a median of 4 years (range: 1-12 years) after surgery. Mean preoperative symptom duration was 18 months (range: 6-106 months) with a mean sick leave duration of 2.3±4.9 months. Postoperatively, mean time to recovery was 37.5 days (range: 7 days to 5 years) and mean sick leave duration was 2.4±2.4 months. The mean Quick-DASH score was 15.9±19.1. The Nirschl score improved significantly, from 26.4±7.9 to 66.3±16.3. The initial muscle strength deficit was 10.1±33.2% and muscle strength at last follow-up was increased by 4.3±30.3%. Symptom duration showed no correlations with any of the clinical outcome measures.

DISCUSSION AND CONCLUSIONS

Outcomes after arthroscopic release were not associated with symptom duration in this study. Nevertheless, the good clinical outcomes support treatment with arthroscopic release after only 6 months of conservative management.

LEVEL OF EVIDENCE

IV, retrospective study.

Mid-term survivorship of Mini-keel™ versus Standard keel in total knee replacements: Differences in the rate of revision for aseptic loosening

INTRODUCTION

To reduce the size of the surgical incision, modular mini-keel tibial components have been developed with or without extensions for the Nexgen™ MIS Tibial Component. Although a smaller component could theoretically result in defective fixation, this has never been evaluated in a large comparative series. Thus, we performed the following case control study to: (1) evaluate intermediate-term survival of a modular "mini-keel" tibial component compared to a reference standard keel component from the same line of products (Nexgen LPS-Flex Tibial Component, Zimmer); (2) to identify any eventual associated factors if the frequency of loosening was increased.

HYPOTHESIS

The rate of revision for aseptic tibial loosening is comparable for both components.

MATERIALS AND METHODS

This comparative, retrospective, single center series of 459 consecutive total knee arthroplasties (TKA) was performed between 2007 and 2010: with 212 modular "mini-keel" (MK) tibial components and 247 "standard" (S) components. Survival, rate of revision for aseptic tibial loosening and identification of a radiolucent line were analyzed at the final follow-up.

RESULTS

After a median follow-up of 5years, the rate of revision for tibial aseptic loosing was significantly higher in the MK group with 12 cases (5.7%) and 4 cases in the S group (1.6%) (P=0.036). The use of the MK component appears to be a prognostic factor for surgical revision (hazard ratio=3.86 (1.23-11.88), P=0.02) but not for the development of a radiolucent line (HR=1.75 (0.9-3.4), P=0.097). The mean delay before revision was 38months (8-64) in the MK group and 15.2months (8-22) in the S group (P=0.006). Individual factors, such as gender, body mass index (BMI) and pre- or postoperative alignment were not prognostic factors for revision or radiolucent lines.

CONCLUSION

The modular "mini-keel" tibial component was associated with a greater risk of revision for tibial component loosening.

LEVEL OF EVIDENCE

Case control study, III.

Culex pipiens and Stegomyia albopicta (= Aedes albopictus) populations as vectors for lineage 1 and 2 West Nile virus in Europe

The emerging disease West Nile fever is caused by West Nile virus (WNV), one of the most widespread arboviruses. This study represents the first test of the vectorial competence of European Culex pipiens Linnaeus 1758 and Stegomyia albopicta (= Aedes albopictus) (both: Diptera: Culicidae) populations for lineage 1 and 2 WNV isolated in Europe. Culex pipiens and S. albopicta populations were susceptible to WNV infection, had disseminated infection, and were capable of transmitting both WNV lineages. This is the first WNV competence assay to maintain mosquito specimens under environmental conditions mimicking the field (day/night) conditions associated with the period of maximum expected WNV activity. The importance of environmental conditions is discussed and the issue of how previous experiments conducted in fixed high temperatures may have overestimated WNV vector competence results with respect to natural environmental conditions is analysed. The information presented should be useful to policymakers and public health authorities for establishing effective WNV surveillance and vector control programmes. This would improve preparedness to prevent future outbreaks.

A quantitative genome-wide RNAi screen in C. elegans for antifungal innate immunity genes

BACKGROUND

Caenorhabditis elegans has emerged over the last decade as a useful model for the study of innate immunity. Its infection with the pathogenic fungus Drechmeria coniospora leads to the rapid up-regulation in the epidermis of genes encoding antimicrobial peptides. The molecular basis of antimicrobial peptide gene regulation has been previously characterized through forward genetic screens. Reverse genetics, based on RNAi, provide a complementary approach to dissect the worm's immune defenses.

RESULTS

We report here the full results of a quantitative whole-genome RNAi screen in C. elegans for genes involved in regulating antimicrobial peptide gene expression. The results will be a valuable resource for those contemplating similar RNAi-based screens and also reveal the limitations of such an approach. We present several strategies, including a comprehensive class clustering method, to overcome these limitations and which allowed us to characterize the different steps of the interaction between C. elegans and the fungus D. coniospora, leading to a complete description of the MAPK pathway central to innate immunity in C. elegans. The results further revealed a cross-tissue signaling, triggered by mitochondrial dysfunction in the intestine, that suppresses antimicrobial peptide gene expression in the nematode epidermis.

CONCLUSIONS

Overall, our results provide an unprecedented system's level insight into the regulation of C. elegans innate immunity. They represent a significant contribution to our understanding of host defenses and will lead to a better comprehension of the function and evolution of animal innate immunity.

Abnormal connectivity in dorsolateral prefrontal cortex in schizophrenia patients and unaffected relatives

Objectives

The aim of this study is to explore connectivity of the left dorsolateral prefrontal cortex (LDLPC) by functional magnetic resonance imaging during resting state, in subjects affected by schizophrenia and unaffected relatives.

Methods

We recruited a group of 29 patients diagnosed with schizophrenia, who were treated with atypical antipsychotics, who are and were clinically stable in the last 6 months and had an illness duration range from 5 up to 15 years. We also recruited a group of 23 unaffected relatives, without history of other mental, neurological or somatic disease and a group of 37 healthy volunteers. No subject in any of the three groups met criteria for substance use disorders.

All three groups were clinically evaluated, and a functional magnetic resonance during Resting State was performed.

Functional images were reoriented to the first scan, normalized to the MNI EPI template and smoothed with an 8 mm Gaussian kernel, with SPM. The CONN-FMRI Toolbox v1.2 was used to create individual subject seed-to-voxel connectivity maps, to the corresponding seeds of the default mode network.

Results

Fig. 1.

Conclusions

Our results show a significant increase in connectivity between LDLPC and anterior prefrontal cortex, dorsolateral prefrontal cortex and somatosensory association areas, especially between patients and controls. It is noteworthy to mention that we found a significant decrease in connectivity between LDLPC and supramarginal gyrus, superior temporal gyrus and somatosensory association areas between unaffected relatives and controls.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Cortical and subcortical morphology deficits in cerebral gray matter in patients with schizophrenia and not affected siblings

Objective

Explore the basis of cortical morphometry in patients with schizophrenia and non-affected siblings by Magnetic Resonance Structural analyzing cortical thickness.

Methods

Twenty-nine patients with schizophrenia treated with atypical antipsychotics and clinically stable in the last 6 months were recruited. Twenty-three not affected siblings of patients with schizophrenia and 37 healthy volunteers were recruited. Magnetic Resonance Structural was performed. FreeSurfer the brain imaging software package for analysis of Cortical Thickness is used. In the analysis of group differences in cortical thickness (CT) with the general linear model (GLM), the P-value was established in 0003 following the Bonferroni correction to control for multiple comparisons (seven regions of interest a priori in each hemisphere).

Results

Significant differences in cortical thickness between patients and healthy controls. Differences between groups were calculated by general linear model (GLM) with age and sex as covairables (Table 1).

Conclusions

In applying the correction for multiple comparisons, differences in bilateral-lateral orbitofrontal, medial orbitofrontal-right and left temporal transverse frontal cortex are significant. Our study replicates previous findings and provides further evidence of abnormalities in the cerebral cortex, particularly in the frontal and temporal regions, being characteristic of schizophrenia.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Acknowledgements

L. Galindo is a Rio-Hortega-fellowship-(ISC-III; CM14/00111).

Meniscectomy versus meniscal repair: 10 years radiological and clinical results in vertical lesions in stable knee

INTRODUCTION

Surgical management of meniscal lesion consists of either a meniscectomy or meniscal repair. Although repair offers immediate recovery after surgery, it is also associated with higher rates of revision. A meniscectomy, on the other hand is known to be associated with an early onset of osteoarthritis. The present study compared clinical and radiological results at 10 years between meniscectomy and meniscal repair in isolated vertical lesion in an otherwise stable knee. The hypothesis was that repair shows functional and radiological benefit over meniscectomy.

PATIENTS AND METHOD

A multi-centric retrospective comparative study of 32 patients (24 male, 8 female). Mean follow-up was 10.6 years (range, 10-13 years). There were 10 meniscal repairs (group R) and 22 meniscectomies (group M), in 17 right and 15 left knees. Mean age at surgery was 33.45±12.3 years (range, 9-47 years). There were 28 medial and 4 lateral meniscal lesions; 26 were in the red-red zone and 6 in red-white zone.

RESULTS

Functional score: KOOS score was significantly higher in group R than M on almost all parameters: 98±4.69 versus 77.38±21.97 for symptoms (P=0.0043), 96.89±7.20 versus 78.57±18.9 for pain (P=0.0052), 99.89±0.33 versus 80.88±19.6 for daily life activities (P=0.0002), 96.11±9.83 versus 54.05±32.85 for sport and leisure (P=0.0005), but 91±16.87 versus 68.15±37.7 for quality of life (P=0.1048). Radiology score: in group R, 7 patients had no features of osteoarthritis, and 2 had grade 1 osteoarthritis. In group M, 5 patients had grade 1 osteoarthritis, 10 grade 2, 3 grade 3 and 3 grade 4. Mean quantitative score was 0 (mean, 0.22±0.44) in-group R and 2 (mean, 2.19±0.98) in group M (P<0.0001).

DISCUSSION

At more than 10year's follow-up, functional scores were significantly better with meniscal repair than meniscectomy on all parameters of the KOOS scale except quality of life. Functional and radiological scores correlated closely. These results show that meniscal repair for vertical lesions in stable knees protects against osteoarthritis and is therefore strongly recommended.

LEVEL OF EVIDENCE

IV; retrospective study.

Poor reproducibility of the MRI measurement of distal femoral torsion

Recent publications on patient-specific instrumentation for total knee arthroplasty have reported considerable variability in the axial positioning of the cutting guides for the femoral component. These personalized cutting guides are manufactured based on bone shape data, generated from magnetic resonance imaging (MRI) or computed tomography (CT). The goal of this study was to compare the reproducibility and accuracy of distal femoral torsion (DFT) values measured using these two imaging modalities. We hypothesized that MRI does not reproducibly and consistently measure DFT and is not as accurate as CT scan.

METHODS

Anonymized radiology records from 54 patients that included MRI and CT scans of the knee were read in random order by two observers, on two separate occasions. These records were from patients being considered for a meniscal or osteochondral graft and who had their knee explored, but who had not undergone femoral or tibial surgery and were free of osteoarthritis. The DFT was estimated using the posterior condylar angle (PCA), using both its anatomical and surgical definitions. The intra- and inter-observer reproducibility of the MRI and the differences relative to CT scan measurements were analysed.

RESULTS

The average intra-observer difference for the MRI evaluation of the anatomical PCA was 0.8±1.2°; it was 0.4±0.9° for the surgical PCA. More than 1° difference from the average was found in 8 cases (14%) using the anatomical PCA measurement and 4 cases (7.4%) when using the surgical PCA (P=0.4). The intraclass correlation coefficients (ICCs) were 0.67 (95% CI: 0.33-0.85) and 0.74 (95% CI: 0.47-0.89) for the anatomical and surgical PCA, respectively. The average inter-observer difference for the MRI evaluation of the anatomical PCA was 1.6±1.4°; it was 1.5±1.0° for the surgical PCA. More than 1° difference from the average was found in 27 cases (50%) using the anatomical PCA measurement and 22 cases (40%) when using the surgical PCA (P=0.4). The ICCs were 0.31 (95% CI: 0.14-0.65) and 0.48 (95% CI: 0.06-0.75) for the anatomical and surgical PCA, respectively. The average differences between the CT and MRI measurements were 1.4±1.1° (0.2-5°) and 1.1±0.8° (0-3.6°) for the anatomical and surgical PCA, respectively. Greater than 1° difference between CT and MRI was found in 29 records (54%) for the anatomical PCA and in 18 records (33%) for the surgical PCA (P=0.03).

CONCLUSION

DFT measurement on MRI is more reproducible and consistent when using the surgical PCA. MRI measurements differed by more than 1° relative to CT measurements in more than one-third of cases.

CASE CONTROL STUDY

Level III.

Meniscal survival rate after anterior cruciate ligament reconstruction

BACKGROUND

Meniscal suture provides well-documented benefits. Integrity of the cruciate ligaments of the knee is a prerequisite for meniscal healing. Nevertheless, reconstruction of the anterior cruciate ligament (ACL) does not consistently prevent recurrent tearing of a sutured meniscus. We evaluated meniscal survival rates, 5 and 10 years after meniscal suture concomitant with an ACL reconstruction. We compared the outcomes of these repaired menisci to those in which no menisci tears were detected during ACL reconstruction.

METHODS

In this multi-centric retrospective study, we included two groups. One group consists of patients who underwent a meniscal repair. This group was further divided into two subgroups based on whether follow-up was 5 years (n=76) or 10 years (n=39). The control group included 120 patients with normal menisci observed during surgery. We studied meniscal survival rates in each group, and we analyzed risk factors associated with the recurrence of meniscal lesions.

RESULTS

The 5-year meniscal survival rate was significantly higher in the control group than in the meniscal-repair group (95% vs. 80%, respectively; P=0.0029). The controls group also had a higher meniscal survival rate after 10 years, although the difference was not statistically significant (88% vs. 77%, P=0.07). A difference in knee laxity greater than 4mm was associated with a 5-fold increase in the risk of recurrent meniscal tears (P=0.0057). After 5 years, the risk of recurrence was higher for the medial than for the lateral meniscus, whereas after 10 years the difference was no longer statistically significant.

DISCUSSION

Although insufficient healing after meniscal suturing contributes to the risk of further meniscal tears, new lesions can develop in menisci that were undamaged at the time of ACL reconstruction. The risk of a new meniscal lesion is strongly associated with inadequate control of antero-posterior and rotational laxity. Some apparently "new menisci lesions" seems to have been missed during ACL reconstruction.

LEVEL OF EVIDENCE

IV, retrospective study.

Early- and late-onset Alzheimer disease: Are they the same entity?

Early-onset Alzheimer disease (EOAD), which presents in patients younger than 65 years, has frequently been described as having different features from those of late-onset Alzheimer disease (LOAD). This review analyses the most recent studies comparing the clinical presentation and neuropsychological, neuropathological, genetic, and neuroimaging findings of both types in order to determine whether EOAD and LOAD are different entities or distinct forms of the same entity. We observed consistent differences between clinical findings in EOAD and in LOAD. Fundamentally, the onset of EOAD is more likely to be marked by atypical symptoms, and cognitive assessments point to poorer executive and visuospatial functioning and praxis with less marked memory impairment. Alzheimer-type features will be more dense and widespread in neuropathology studies, with structural and functional neuroimaging showing greater and more diffuse atrophy extending to neocortical areas (especially the precuneus). In conclusion, available evidence suggests that EOAD and LOAD are 2 different forms of a single entity. LOAD is likely to be influenced by ageing-related processes.