A Novel Silicone Simulation Model for Microvascular Anastomosis.

Purpose: Surgical simulation of microvascular anastomosis has become increasingly popular. There are several living and silicone models available. Current silicone models fail to accurately reproduce a vessel's loose adventitial layer, which may lead to the development of improper microsurgical technique. Our purpose is to create a realistic 3-dimensional microsurgical simulator that incorporates an adventitial vessel layer for higher fidelity manipulation of vessels. Methods: A microvascular anastomosis simulator was manufactured using metal moulds and inorganic materials. Synthetic tubing was created with a metal cylinder, 1.65 mm in diameter, painted with 2 sequential layers of silicon with a shore hardness of 2A. Silicone was allowed to fully cure in-between layers. Vessel adventitia was created with a 100-micron polyester mesh adhered to the silicone vessel exterior. Once dry, the synthetic tube is removed from the metal cylinder is then clipped to reveal the inner lumen. Both Resident and attending physicians evaluated the model with and without the adventitial layer and completed a questionnaire. Results: Grasping and manipulation of the vessel were scored on Average score 4.5 and 3 out of 5, with adventitia and without, respectively (P = .00906). Usefulness as a teaching tool was scored on average 4.9 and 4.2, with adventitia and without, respectively (P = .0232). The analysis included: simulation realism, educational utility, and overall satisfaction. Responses in all domains were favourable, suggesting the utility of this model. Conclusion: We created a realistic, high fidelity microvascular anastomosis simulator that is low cost and easily reproducible. Initial feedback is encouraging regarding realism, educational utility, and overall usefulness. Further validation is required to assess its effectiveness in resident education and skill transfer to the operating room.

Objectif: La simulation chirurgicale de l'anastomose microvasculaire gagne en popularité. Il existe plusieurs modèles de simulation vivants ou en silicone. Les modèles actuels en silicone ne réussissent pas à reproduire la couche adventitielle lâche, ce qui peut entraîner une technique microchirurgicale inappropriée. Les chercheurs voulaient créer un simulateur microchirurgical tridimensionnel réaliste doté d'une couche adventitielle pour manipuler les vaisseaux avec plus de fiabilité. Méthodologie: Les chercheurs ont fabriqué un simulateur d'anastomose microvasculaire au moyen de moules métalliques et de matières inorganiques. Ils ont créé des tubulures synthétiques à l'aide d'un cylindre métallique d'un diamètre de 1,65 mm, qu'ils ont peint de deux couches séquentielles de silicone d'une dureté Shore A de 2. Ils ont laissé le silicone durcir complètement entre les couches et ont créé la couche adventitielle à l'aide d'une maille de polyester de 100 microns fixée à l'extérieur du vaisseau de silicone. Une fois sèche, la tubulure synthétique est retirée du cylindre métallique, puis coupée pour révéler la lumière interne. Des résidents et des médecins traitants ont évalué le modèle avec et sans la couche adventitielle et rempli un questionnaire. Résultats: La saisie et la manipulation du vaisseau ont obtenu un score moyen de 4,5 et de 3 sur 5, avec et sans la couche adventitielle, respectivement (p = 0,00906). L'utilité de ce vaisseau comme outil d'enseignement a obtenu un score moyen de 4,9 et de 4,2, avec et sans la couche adventitielle, respectivement (p = 0,0232). L'analyse incluait le réalisme de la simulation, l'utilité pour l'enseignement et la satisfaction globale. Les réponses étaient favorables dans tous les domaines, ce qui laisse croire à l'utilité du modèle. Conclusion: Les chercheurs ont créé un simulateur d'anastomose microvasculaire haute-fidélité réaliste, à la fois peu coûteux et facile à reproduire. Les premiers commentaires sont encourageants pour ce qui est du réalisme, de l'utilité pour l'enseignement et de l'utilité globale. Son efficacité lors de l'enseignement aux résidents et du transfert du savoir en salle d'opération devra être validée davantage.

Human immunocompetent Organ-on-Chip platforms allow safety profiling of tumor-targeted T-cell bispecific antibodies.

Traditional drug safety assessment often fails to predict complications in humans, especially when the drug targets the immune system. Here, we show the unprecedented capability of two human Organs-on-Chips to evaluate the safety profile of T-cell bispecific antibodies (TCBs) targeting tumor antigens. Although promising for cancer immunotherapy, TCBs are associated with an on-target, off-tumor risk due to low levels of expression of tumor antigens in healthy tissues. We leveraged in vivo target expression and toxicity data of TCBs targeting folate receptor 1 (FOLR1) or carcinoembryonic antigen (CEA) to design and validate human immunocompetent Organs-on-Chips safety platforms. We discovered that the Lung-Chip and Intestine-Chip could reproduce and predict target-dependent TCB safety liabilities, based on sensitivity to key determinants thereof, such as target expression and antibody affinity. These novel tools broaden the research options available for mechanistic understandings of engineered therapeutic antibodies and assessing safety in tissues susceptible to adverse events.

Modeling alcohol-associated liver disease in a human Liver-Chip.

Alcohol-associated liver disease (ALD) is a global health issue and leads to progressive liver injury, comorbidities, and increased mortality. Human-relevant preclinical models of ALD are urgently needed. Here, we leverage a triculture human Liver-Chip with biomimetic hepatic sinusoids and bile canaliculi to model ALD employing human-relevant blood alcohol concentrations (BACs) and multimodal profiling of clinically relevant endpoints. Our Liver-Chip recapitulates established ALD markers in response to 48 h of exposure to ethanol, including lipid accumulation and oxidative stress, in a concentration-dependent manner and supports the study of secondary insults, such as high blood endotoxin levels. We show that remodeling of the bile canalicular network can provide an in vitro quantitative readout of alcoholic liver toxicity. In summary, we report the development of a human ALD Liver-Chip as a powerful platform for modeling alcohol-induced liver injury with the potential for direct translation to clinical research and evaluation of patient-specific responses.

Surgeon-administered Ultrasound-guided Peripheral Nerve Blocks in Outpatient Procedures of the Upper Extremity.

Outpatient hand surgery is often performed in the operating room, which can result in prolonged waiting times for patients when operating room resources are limited. Few studies have explored the application of ultrasound-guided nerve blocks in the setting of outpatient hand surgery. Fifty patients were enrolled in this prospective study. Ultrasound-guided peripheral nerve blocks were performed at the level of the elbow and proximal forearm for outpatient hand surgeries. A timer was used to record the time to administer the block and time to affect. A post-procedure survey was administered, which included a numerical analogue scale (0-10) and Likert rating scale questions to characterize the patients' pain experience for receiving the block and pain during the procedure: pain experienced by patients receiving the ultrasound-guided nerve block(s) (0-10), mean: 1.84; pain experienced by patients during a procedure (0-10), mean: 0.56; surgeon satisfaction during the procedure (0-10), mean 9.78. Average time to perform the ultrasound-guided nerve block(s) was 4 minutes 58 seconds; average time from completion of the block to effect reported by patients, 5 minutes 42 seconds; the average time for performing the procedure, 21 minutes 30 seconds. Our study shows that the use of ultrasound to block peripheral nerves of the forearm is effective; <10% of patients required additional local anesthetic. The technique is safe; no complications were reported. The technique is efficient in an outpatient hand surgery setting.

An unusual skin infection with Achromobacter xylosoxidans.

Achromobacter xylosoxidans is an emerging, multidrug-resistant pathogen capable of forming biofilms on medical products that primarily infects immunocompromised patients. We present the case of a 50-year-old immunocompetent woman who developed an A xylosoxidans granulomatous abscess at the attachment site of her insulin pump. She was successfully treated with surgical excision and oral trimethoprim-sulfamethoxazole (TMP-SMX). This case demonstrates further emergence of A xylosoxidans as a potential pathogen, not only in immunocompromised individuals but in any patient with an indwelling catheter.

Gouty Stenosing Tenosynovitis: Trigger Finger as a First Presentation of Tophaceous Gout.

Gout can lead to the deposition of tophi and chronic arthritis, for which surgical management is indicated when tophi interfere with the function of the finger. This case report discusses the management of a 37-year-old man with a past medical history of gout who presented with triggering of his small finger from gouty infiltration of his flexor digitorum profundus (FDP) tendon. An exploratory procedure that included tenolysis and release of the A1 pulley was performed. Gouty infiltration of the FDP tendon was noted intraoperatively and biopsied, which was later confirmed by histopathological analysis as being gouty tophus. The patient regained full function of the affected finger postoperatively and has since had no recurrence. Gouty tenosynovitis is a rare cause of trigger finger and should be considered as part of the differential diagnosis. Treatment for gouty tenosynovitis consists of A1 pulley release and careful excision of gouty tophus to restore tendon glide and hand function.

Validation of a novel strabismus surgery 3D-printed silicone eye model for simulation training.

PURPOSE: To demonstrate the validity of a new 3D-printed silicone model for practicing strabismus surgery, compared with the rabbit head, in terms of simulator fidelity. METHODS: In this multicenter study, a validated questionnaire was developed to assess fidelity of the model and rabbit head. Participants were asked to rate overall globe, conjunctiva, muscle, and scleral fidelity using a 5-point scale. The survey instrument was disseminated at three strabismus instruction courses: at two meetings, participants practiced on the model and rabbit head prior to completing the questionnaire; at the third, instructors demonstrated advanced surgical skills using only the model and then completed the questionnaire. Repeated measures analysis of variance compared ratings. Pearson's or Spearman's correlation evaluated correlation between years of experience to participants' responses. Qualitative data were coded into themes. RESULTS: A total of 47 participants completed the questionnaire. The model rated 18% higher than rabbit head for anatomical accuracy (mean difference, 0.667; P = 0.001) and 25% higher for position of eyes within the head (mean difference, 0.867; P = 0.006). More experienced participants were more likely to strongly agree that the silicone conjunctiva effectively mimics real conjunctiva (ρ = 0.337; P = 0.036) and that scleral tissue effectively mimics real sclera (ρ = 0.298, P = 0.042). Qualitative data supported the model. CONCLUSIONS: This study demonstrated the validity of the surgical model in terms of fidelity compared to the rabbit head.

Reproducing human and cross-species drug toxicities using a Liver-Chip.

Nonclinical rodent and nonrodent toxicity models used to support clinical trials of candidate drugs may produce discordant results or fail to predict complications in humans, contributing to drug failures in the clinic. Here, we applied microengineered Organs-on-Chips technology to design a rat, dog, and human Liver-Chip containing species-specific primary hepatocytes interfaced with liver sinusoidal endothelial cells, with or without Kupffer cells and hepatic stellate cells, cultured under physiological fluid flow. The Liver-Chip detected diverse phenotypes of liver toxicity, including hepatocellular injury, steatosis, cholestasis, and fibrosis, and species-specific toxicities when treated with tool compounds. A multispecies Liver-Chip may provide a useful platform for prediction of liver toxicity and inform human relevance of liver toxicities detected in animal studies to better determine safety and human risk.

Integrated in vitro models for hepatic safety and metabolism: evaluation of a human Liver-Chip and liver spheroid.

Drug-induced liver injury remains a frequent reason for drug withdrawal. Accordingly, more predictive and translational models are required to assess human hepatotoxicity risk. This study presents a comprehensive evaluation of two promising models to assess mechanistic hepatotoxicity, microengineered Organ-Chips and 3D hepatic spheroids, which have enhanced liver phenotype, metabolic activity and stability in culture not attainable with conventional 2D models. Sensitivity of the models to two hepatotoxins, acetaminophen (APAP) and fialuridine (FIAU), was assessed across a range of cytotoxicity biomarkers (ATP, albumin, miR-122, α-GST) as well as their metabolic functionality by quantifying APAP, FIAU and CYP probe substrate metabolites. APAP and FIAU produced dose- and time-dependent increases in miR-122 and α-GST release as well as decreases in albumin secretion in both Liver-Chips and hepatic spheroids. Metabolic turnover of CYP probe substrates, APAP and FIAU, was maintained over the 10-day exposure period at concentrations where no cytotoxicity was detected and APAP turnover decreased at concentrations where cytotoxicity was detected. With APAP, the most sensitive biomarkers were albumin in the Liver-Chips (EC50 5.6 mM, day 1) and miR-122 and ATP in the liver spheroids (14-fold and EC50 2.9 mM, respectively, day 3). With FIAU, the most sensitive biomarkers were albumin in the Liver-Chip (EC50 126 µM) and miR-122 (15-fold) in the liver spheroids, both on day 7. In conclusion, both models exhibited integrated toxicity and metabolism, and broadly similar sensitivity to the hepatotoxicants at relevant clinical concentrations, demonstrating the utility of these models for improved hepatotoxicity risk assessment.

Introducing an automated high content confocal imaging approach for Organs-on-Chips.

Organ-Chips are micro-engineered systems that aim to recapitulate the organ microenvironment. Implementation of Organ-Chips within the pharmaceutical industry aims to improve the probability of success of drugs reaching late stage clinical trial by generating models for drug discovery that are of human origin and have disease relevance. We are adopting the use of Organ-Chips for enhancing pre-clinical efficacy and toxicity evaluation and prediction. Whilst capturing cellular phenotype via imaging in response to drug exposure is a useful readout in these models, application has been limited due to difficulties in imaging the chips at scale. Here we created an end-to-end, automated workflow to capture and analyse confocal images of multicellular Organ-Chips to assess detailed cellular phenotype across large batches of chips. By automating this process, we not only reduced acquisition time, but we also minimised process variability and user bias. This enabled us to establish, for the first time, a framework of statistical best practice for Organ-Chip imaging, creating the capability of using Organ-Chips and imaging for routine testing in drug discovery applications that rely on quantitative image data for decision making. We tested our approach using benzbromarone, whose mechanism of toxicity has been linked to mitochondrial damage with subsequent induction of apoptosis and necrosis, and staurosporine, a tool inducer of apoptosis. We also applied this workflow to assess the hepatotoxic effect of an active AstraZeneca drug candidate illustrating its applicability in drug safety assessment beyond testing tool compounds. Finally, we have demonstrated that this approach could be adapted to Organ-Chips of different shapes and sizes through application to a Kidney-Chip.

The Canadian Model for Instituting Wide-Awake Hand Surgery in Our Hospitals.

Clinic-based hand surgery performed under local anesthetic has been steadily increasingly performed in Canada for 50 years. The drive for its development stems from the Canadian health care system's finite funding structure and resources. Benefits have extended far beyond cost and garbage reduction. It has resulted in greatly improving patient care by increasing comfort and safety with the elimination of sedation, the tourniquet, night surgery, and by improving access to care. This article details the rationale and development of clinic-based hand surgery from a Canadian perspective and provides tips and strategies for other centers looking to implement a similar clinic.

Acetylation is the most abundant actin modification in Entamoeba histolytica and modifications of actin's amino-terminal domain change cytoskeleton activities.

Actin is one of the most conserved, abundant, and ubiquitous proteins in all eukaryotes characterised to date. Posttranslation modifications of actin modify the organisation of the actin-rich cytoskeleton. In particular, chemical modifications of actin's amino-terminal region determine how filamentous actin is organised into scaffolds. After assuming that protein modifications account for the multiple functional activities exerted by the single actin in Entamoeba histolytica, we profiled posttranslational modifications of this protein. Acetylation (on 21 different amino acids) was the most abundant modification, followed by phosphorylation. Furthermore, the glycine residue at Position 2 in E. histolytica's actin (Gly2, not found in most other eukaryotic actins) was found to be acetylated. The impact of Gly2 on the amoeba's life cycle and pathogenicity was then assessed in mutagenesis experiments. We found that Gly2 was necessary for cell morphology and division, parasite-host cell adhesion, and host invasion in an in vitro model of amoebic human infection.

Vascularized Pedicled Proximal Phalanx Flap for Spare Part for Reconstruction of Metacarpal Avulsion Injury.

Traumatic injuries to the hand with significant loss of bone or soft tissue can be quite difficult to reconstruct and often require an innovative and flexible surgical plan for reconstruction. We present a case of a young manual laborer with a significant crush avulsion injury involving his third and fourth metacarpals. We were able to preserve his fourth metacarpophalangeal joint by utilizing a pedicled vascularized proximal phalanx flap from the nonsalvageable third digit to reconstruct and provide osseous stability to the fourth metacarpal. The patient had excellent functional and aesthetic outcomes with full return to work at his farm by less than 12 months postoperatively.

Three-dimensional Printed Surgical Simulator for Kirschner Wire Placement in Hand Fractures.

Closed reduction and percutaneous pinning (CRPP) of hand fractures can be a deceptively challenging procedure that requires significant hands-on time to teach and learn. We created a realistic three-dimensional simulator that can be used for teaching junior residents the CRPP. Computer-aided design and computer-aided manufacturing (CAD/CAM) software was used to create a three-dimensional hand model incorporating several common hand fractures: Bennett's fracture, transverse fifth metacarpal neck, and transverse second proximal phalanx. Three-dimensional printing was used to create molds in which the bones and soft tissue were poured. A polyurethane foam was utilized for the bones with iron incorporated to render them radiopaque, whereas silicone of varying viscosities was used for the soft tissues. Five plastic surgery residents and 5 consultants evaluated the model. Individuals then completed an anonymous 12-question survey evaluating the model based on realism, educational utility, and overall usefulness. Survey responses obtained from both residents and consultants were strongly in favor of the simulator. Average realism was graded as 4.48/5 by residents and 4.68/5 by consultants. Average educational utility was graded as 5/5 by residents and 4.95/5 by consultants. Average overall usefulness was graded as 5/5 by both groups. We created an anatomically accurate and realistic simulator for CRPP of hand fractures that was low cost and easily reproducible. Initial feedback was encouraging in regard to realism, educational utility, and overall usefulness.

Lichen planus pemphigoides treated with ustekinumab.

A 71-year-old woman presented with pink to violaceous, flat-topped, polygonal papules on the volar wrists, extensor elbows, and bilateral lower legs of 3 years' duration. She also had erythematous, violaceous, infiltrated plaques with microvesiculation on the bilateral thighs of several months' duration. She reported pruritus, burning, and discomfort. Her medical history included type 2 diabetes mellitus, hypertension, and asthma with no history of skin rashes. Workup revealed lichen planus pemphigoides (LPP), a rare papulosquamous and vesiculobullous dermatosis that shares features of both lichen planus (LP) and bullous pemphigoid (BP). Despite multiple traditional therapies, her disease continued to progress, further developing mucosal disease. After a review of the literature on LP, BP, and LPP, it was noted that tumor necrosis factor α (TNF-α), along with other cytokines, plays a pivotal role in all 3 diseases. After several conventional systemic therapies failed, we treated our patient with ustekinumab with favorable results.

Human Liver Infection in a Dish: Easy-To-Build 3D Liver Models for Studying Microbial Infection.

Human liver infection is a major cause of death worldwide, but fundamental studies on infectious diseases affecting humans have been hampered by the lack of robust experimental models that accurately reproduce pathogen-host interactions in an environment relevant for the human disease. In the case of liver infection, one consequence of this absence of relevant models is a lack of understanding of how pathogens cross the sinusoidal endothelial barrier and parenchyma. To fill that gap we elaborated human 3D liver in vitro models, composed of human liver sinusoidal endothelial cells (LSEC) and Huh-7 hepatoma cells as hepatocyte model, layered in a structure mimicking the hepatic sinusoid, which enable studies of key features of early steps of hepatic infection. Built with established cell lines and scaffold, these models provide a reproducible and easy-to-build cell culture approach of reduced complexity compared to animal models, while preserving higher physiological relevance compared to standard 2D systems. For proof-of-principle we challenged the models with two hepatotropic pathogens: the parasitic amoeba Entamoeba histolytica and hepatitis B virus (HBV). We constructed four distinct setups dedicated to investigating specific aspects of hepatic invasion: 1) pathogen 3D migration towards hepatocytes, 2) hepatocyte barrier crossing, 3) LSEC and subsequent hepatocyte crossing, and 4) quantification of human hepatic virus replication (HBV). Our methods comprise automated quantification of E. histolytica migration and hepatic cells layer crossing in the 3D liver models. Moreover, replication of HBV virus occurs in our virus infection 3D liver model, indicating that routine in vitro assays using HBV or others viruses can be performed in this easy-to-build but more physiological hepatic environment. These results illustrate that our new 3D liver infection models are simple but effective, enabling new investigations on infectious disease mechanisms. The better understanding of these mechanisms in a human-relevant environment could aid the discovery of drugs against pathogenic liver infection.

Accuracy of medical models made by consumer-grade fused deposition modelling printers.

BACKGROUND: Additive manufacturing using fused deposition modelling (FDM) has become widely available with the development of consumer-grade three-dimensional printers. To be useful in maxillofacial surgery, models created by these printers must accurately reproduce the craniofacial skeleton. OBJECTIVE: To determine the accuracy of consumer-grade FDM printers in the production of medical models compared with industrial selective laser sintering (SLS) printers. METHODS: Computed tomography images of a dry skull were manipulated using OsiriX (OsiriX, Switzerland) and ZBrush (Pixologic, USA) software. Models were fabricated using a consumer-grade FDM printer at 100 µm, 250 µm and 500 µm layer heights and an industrial SLS printer. Seven linear measurements were made on the models and compared with the corresponding dry skull measurements using an electronic caliper. RESULTS: A dimensional error of 0.30% was observed for the SLS models and 0.44%, 0.52% and 1.1% for the 100 µm, 250 µm and 500 µm FDM models, respectively. CONCLUSION: Consumer-grade FDM printers can produce medical models with sufficient dimensional accuracy for use in maxillofacial surgery. With this technology, surgeons can independently produce low-cost maxillofacial models in an office setting.

HISTORIQUE: La fabrication additive faisant appel à la modélisation par dépôt de fil en fusion (FDM) s'est généralisée grâce au développement des imprimantes tridimensionnelles pour consommation courante. Pour être utiles en chirurgie maxillo-faciale, les modèles créés par ces imprimantes doivent reproduire le squelette craniofacial avec précision. OBJECTIF: Déterminer la précision d'imprimantes FDM pour consommation courante dans la production de modèles médicaux par rapport à des imprimantes industrielles faisant appel au frittage sélectif par laser (SLS). MÉTHODOLOGIE: Les chercheurs ont manipulé les images tomodensitométriques d'un crâne séché à l'aide des logiciels OsiriX (OsiriX, Suisse) et ZBrush (Pixologic, États-Unis). Ils ont fabriqué les modèles à l'aide d'une imprimante FDM pour consommation courante, à des épaisseurs de couche de 100 µm, 250 µm et 500 µm, ainsi qu'à l'aide d'une imprimante SLS industrielle. Au moyen d'un pied à coulisse électronique, ils ont effectué sept mesures linéaires sur les modèles, qu'ils ont comparées aux mesures du crâne séché. RÉSULTATS: Les chercheurs ont observé une erreur dimensionnelle de 0,30 % dans les modèles SLS et de 0,44 %, 0,52 % et 1,1 % dans les modèles FDM à 100 µm, 250 µm et 500 µm, respectivement. CONCLUSION: Les imprimantes FDM pour consommation courante produisent des modèles médicaux de précision dimensionnelle suffisante pour être utilisés en chirurgie maxillo-faciale. Grâce à cette technologie, les chirurgiens peuvent produire eux-mêmes des modèles maxillo-faciaux à faible coût en cabinet.

Cardiac emergencies in neurosurgical patients.

Perioperative safety concerns are a major area of interest in recent years. Severe cardiac perturbation such as cardiac arrest is one of the most dreaded complications in the intraoperative period; however, little is known about the management of these events in the patients undergoing elective neurosurgery. This special group needs further attention, as it is often neither feasible nor appropriate to apply conventional advanced cardiac life support algorithms in patients undergoing neurosurgery. Factors such as neurosurgical procedure and positioning can also have a significant effect on the occurrence of cardiac arrest. Therefore, the aim of this paper is to describe the various causes and management of cardiac emergencies with special reference to cardiac arrest during elective neurosurgical procedures, including discussion of position-related factors and resuscitative considerations in these situations. This will help to formulate possible guidelines for management of such events.

Abdominal compartment syndrome following abdominoplasty: A case report and review.

Abdominoplasty is among the most commonly performed aesthetic procedures in plastic surgery. Despite high complication rate, abdominal contouring procedures are expected to rise in popularity with the advent of bariatric surgery. Patients with a history of gastric bypass surgery have an elevated incidence of small bowel obstruction from internal herniation, which is associated with non-specific upper abdominal pain, nausea, and a decrease in appetite. Internal hernias, when subjected to elevated intra-abdominal pressures, have a high-risk of developing ischemic bowel. We present a case report of patient with previous laparoscopic Roux-en-y gastric bypass who developed acute ischemic bowel leading to abdominal compartment syndrome following abdominoplasty. To the best of our knowledge, this is the first reported case in the literature. We herein emphasise on the subtle symptoms and signs that warrant further investigations in prospective patients for an abdominal contouring procedure with a prior history of gastric bypass surgery.

A new human 3D-liver model unravels the role of galectins in liver infection by the parasite Entamoeba histolytica.

Investigations of human parasitic diseases depend on the availability of appropriate in vivo animal models and ex vivo experimental systems, and are particularly difficult for pathogens whose exclusive natural hosts are humans, such as Entamoeba histolytica, the protozoan parasite responsible for amoebiasis. This common infectious human disease affects the intestine and liver. In the liver sinusoids E. histolytica crosses the endothelium and penetrates into the parenchyma, with the concomitant initiation of inflammatory foci and subsequent abscess formation. Studying factors responsible for human liver infection is hampered by the complexity of the hepatic environment and by the restrictions inherent to the use of human samples. Therefore, we built a human 3D-liver in vitro model composed of cultured liver sinusoidal endothelial cells and hepatocytes in a 3D collagen-I matrix sandwich. We determined the presence of important hepatic markers and demonstrated that the cell layers function as a biological barrier. E. histolytica invasion was assessed using wild-type strains and amoebae with altered virulence or different adhesive properties. We showed for the first time the dependence of endothelium crossing upon amoebic Gal/GalNAc lectin. The 3D-liver model enabled the molecular analysis of human cell responses, suggesting for the first time a crucial role of human galectins in parasite adhesion to the endothelial cells, which was confirmed by siRNA knockdown of galectin-1. Levels of several pro-inflammatory cytokines, including galectin-1 and -3, were highly increased upon contact of E. histolytica with the 3D-liver model. The presence of galectin-1 and -3 in the extracellular medium stimulated pro-inflammatory cytokine release, suggesting a further role for human galectins in the onset of the hepatic inflammatory response. These new findings are relevant for a better understanding of human liver infection by E. histolytica.