Microphysiological pancreas-on-chip platform with integrated sensors to model endocrine function and metabolism

Pancreatic in vitro research is of major importance to advance mechanistic understanding and development of treatment options for diseases such as diabetes mellitus. We present a thermoplastic-based microphysiological system aiming to model the complex microphysiological structure and function of the endocrine pancreas with concurrent real-time read-out capabilities. The specifically tailored platform enables self-guided trapping of single islets at defined locations: β-cells are assembled to pseudo-islets and injected into the tissue chamber using hydrostatic pressure-driven flow. The pseudo-islets can further be embedded in an ECM-like hydrogel mimicking the native microenvironment of pancreatic islets in vivo. Non-invasive real-time monitoring of the oxygen levels on-chip is realized by the integration of luminescence-based optical sensors to the platform. To monitor insulin secretion kinetics in response to glucose stimulation in a time-resolved manner, an automated cycling of different glucose conditions is implemented. The model's response to glucose stimulation can be monitored via offline analysis of insulin secretion and via specific changes in oxygen consumption due to higher metabolic activity of pseudo-islets at high glucose levels. To demonstrate applicability for drug testing, the effects of antidiabetic medications are assessed and changes in dynamic insulin secretion are observed in line with the respective mechanism of action. Finally, by integrating human pancreatic islet microtissues, we highlight the flexibility of the platform and demonstrate the preservation of long-term functionality of human endocrine pancreatic tissue.

Autologous Human Immunocompetent White Adipose Tissue-on-Chip

Obesity and associated diseases, such as diabetes, have reached epidemic proportions globally. In this era of "diabesity", white adipose tissue (WAT) has become a target of high interest for therapeutic strategies. To gain insights into mechanisms of adipose (patho-)physiology, researchers traditionally relied on animal models. Leveraging Organ-on-Chip technology, a microphysiological in vitro model of human WAT is introduced: a tailored microfluidic platform featuring vasculature-like perfusion that integrates 3D tissues comprising all major WAT-associated cellular components (mature adipocytes, organotypic endothelial barriers, stromovascular cells including adipose tissue macrophages) in an autologous manner and recapitulates pivotal WAT functions, such as energy storage and mobilization as well as endocrine and immunomodulatory activities. A precisely controllable bottom-up approach enables the generation of a multitude of replicates per donor circumventing inter-donor variability issues and paving the way for personalized medicine. Moreover, it allows to adjust the model's degree of complexity via a flexible mix-and-match approach. This WAT-on-Chip system constitutes the first human-based, autologous, and immunocompetent in vitro adipose tissue model that recapitulates almost full tissue heterogeneity and can become a powerful tool for human-relevant research in the field of metabolism and its associated diseases as well as for compound testing and personalized- and precision medicine applications.

Studying metabolism with multi-organ chips: new tools for disease modelling, pharmacokinetics and pharmacodynamics

Non-clinical models to study metabolism including animal models and cell assays are often limited in terms of species translatability and predictability of human biology. This field urgently requires a push towards more physiologically accurate recapitulations of drug interactions and disease progression in the body. Organ-on-chip systems, specifically multi-organ chips (MOCs), are an emerging technology that is well suited to providing a species-specific platform to study the various types of metabolism (glucose, lipid, protein and drug) by recreating organ-level function. This review provides a resource for scientists aiming to study human metabolism by providing an overview of MOCs recapitulating aspects of metabolism, by addressing the technical aspects of MOC development and by providing guidelines for correlation with in silico models. The current state and challenges are presented for two application areas: (i) disease modelling and (ii) pharmacokinetics/pharmacodynamics. Additionally, the guidelines to integrate the MOC data into in silico models could strengthen the predictive power of the technology. Finally, the translational aspects of metabolizing MOCs are addressed, including adoption for personalized medicine and prospects for the clinic. Predictive MOCs could enable a significantly reduced dependence on animal models and open doors towards economical non-clinical testing and understanding of disease mechanisms.

Human immunocompetent choroid-on-chip: a novel tool for studying ocular effects of biological drugs

Disorders of the eye leading to visual impairment are a major issue that affects millions of people. On the other side ocular toxicities were described for e.g. molecularly targeted therapies in oncology and may hamper their development. Current ocular model systems feature a number of limitations affecting human-relevance and availability. To find new options for pharmacological treatment and assess mechanisms of toxicity, hence, novel complex model systems that are human-relevant and readily available are urgently required. Here, we report the development of a human immunocompetent Choroid-on-Chip (CoC), a human cell-based in vitro model of the choroid layer of the eye integrating melanocytes and microvascular endothelial cells, covered by a layer of retinal pigmented epithelial cells. Immunocompetence is achieved by perfusion of peripheral immune cells. We demonstrate controlled immune cell recruitment into the stromal compartments through a vascular monolayer and in vivo-like cytokine release profiles. To investigate applicability for both efficacy testing of immunosuppressive compounds as well as safety profiling of immunoactivating antibodies, we exposed the CoCs to cyclosporine and tested CD3 bispecific antibodies.

Human stem cell-based retina on chip as new translational model for validation of AAV retinal gene therapy vectors

Gene therapies using adeno-associated viruses (AAVs) are among the most promising strategies to treat or even cure hereditary and acquired retinal diseases. However, the development of new efficient AAV vectors is slow and costly, largely because of the lack of suitable non-clinical models. By faithfully recreating structure and function of human tissues, human induced pluripotent stem cell (iPSC)-derived retinal organoids could become an essential part of the test cascade addressing translational aspects. Organ-on-chip (OoC) technology further provides the capability to recapitulate microphysiological tissue environments as well as a precise control over structural and temporal parameters. By employing our recently developed retina on chip that merges organoid and OoC technology, we analyzed the efficacy, kinetics, and cell tropism of seven first- and second-generation AAV vectors. The presented data demonstrate the potential of iPSC-based OoC models as the next generation of screening platforms for future gene therapeutic studies.

Immunocompetent cancer-on-chip models to assess immuno-oncology therapy

The advances in cancer immunotherapy come with several obstacles, limiting its widespread use and benefits so far only to a small subset of patients. One of the underlying challenges remains to be the lack of representative nonclinical models that translate to human immunity and are able to predict clinical efficacy and safety outcomes. In recent years, immunocompetent Cancer-on-Chip models emerge as an alternative human-based platform that enables the integration and manipulation of complex tumor microenvironment. In this review, we discuss novel opportunities offered by Cancer-on-Chip models to advance (mechanistic) immuno-oncology research, ranging from design flexibility to multimodal analysis approaches. We then exemplify their (potential) applications for the research and development of adoptive cell therapy, immune checkpoint therapy, cytokine therapy, oncolytic virus, and cancer vaccines.

A Critical Perspective on 3D Liver Models for Drug Metabolism and Toxicology Studies

The poor predictability of human liver toxicity is still causing high attrition rates of drug candidates in the pharmaceutical industry at the non-clinical, clinical, and post-marketing authorization stages. This is in part caused by animal models that fail to predict various human adverse drug reactions (ADRs), resulting in undetected hepatotoxicity at the non-clinical phase of drug development. In an effort to increase the prediction of human hepatotoxicity, different approaches to enhance the physiological relevance of hepatic in vitro systems are being pursued. Three-dimensional (3D) or microfluidic technologies allow to better recapitulate hepatocyte organization and cell-matrix contacts, to include additional cell types, to incorporate fluid flow and to create gradients of oxygen and nutrients, which have led to improved differentiated cell phenotype and functionality. This comprehensive review addresses the drug-induced hepatotoxicity mechanisms and the currently available 3D liver in vitro models, their characteristics, as well as their advantages and limitations for human hepatotoxicity assessment. In addition, since toxic responses are greatly dependent on the culture model, a comparative analysis of the toxicity studies performed using two-dimensional (2D) and 3D in vitro strategies with recognized hepatotoxic compounds, such as paracetamol, diclofenac, and troglitazone is performed, further highlighting the need for harmonization of the respective characterization methods. Finally, taking a step forward, we propose a roadmap for the assessment of drugs hepatotoxicity based on fully characterized fit-for-purpose in vitro models, taking advantage of the best of each model, which will ultimately contribute to more informed decision-making in the drug development and risk assessment fields.

The role of epigenetic modifiers in extended cultures of functional hepatocyte-like cells derived from human neonatal mesenchymal stem cells

The development of predictive in vitro stem cell-derived hepatic models for toxicological drug screening is an increasingly important topic. Herein, umbilical cord tissue-derived mesenchymal stem cells (hnMSCs) underwent hepatic differentiation using an optimized three-step core protocol of 24 days that mimicked liver embryogenesis with further exposure to epigenetic markers, namely the histone deacetylase inhibitor trichostatin A (TSA), the cytidine analogue 5-azacytidine (5-AZA) and dimethyl sulfoxide (DMSO). FGF-2 and FGF-4 were also tested to improve endoderm commitment and foregut induction during Step 1 of the differentiation protocol, being HHEX expression increased with FGF-2 (4 ng/mL). DMSO (1%, v/v) when added at day 10 enhanced cell morphology, glycogen storage ability, enzymatic activity and induction capacity. Moreover, the stability of the hepatic phenotype under the optimized differentiation conditions was examined up to day 34. Our findings showed that hepatocyte-like cells (HLCs) acquired the ability to metabolize glucose, produce albumin and detoxify ammonia. Global transcriptional analysis of the HLCs showed a partial hepatic differentiation degree. Global analysis of gene expression in the different cells revealed shared expression of gene groups between HLCs and human primary hepatocytes (hpHeps) that were not observed between HepG2 and hpHeps. In addition, bioinformatics analysis of gene expression data placed HLCs between the HepG2 cell line and hpHeps and distant from hnMSCs. The enhanced hepatic differentiation observed was supported by the presence of the hepatic drug transporters OATP-C and MRP-2 and gene expression of the hepatic markers CK18, TAT, AFP, ALB, HNF4A and CEBPA; and by their ability to display stable UGT-, EROD-, ECOD-, CYP1A1-, CYP2C9- and CYP3A4-dependent activities at levels either comparable with or even higher than those observed in primary hepatocytes and HepG2 cells. Overall, an improvement of the hepatocyte-like phenotype was achieved for an extended culture time suggesting a role of the epigenetic modifiers in hepatic differentiation and maturation and presenting hnMSC-HLCs as an advantageous alternative for drug discovery and in vitro toxicology testing.

Self-assembled 3D spheroids and hollow-fibre bioreactors improve MSC-derived hepatocyte-like cell maturation in vitro

3D cultures of human stem cell-derived hepatocyte-like cells (HLCs) have emerged as promising models for short- and long-term maintenance of hepatocyte phenotype in vitro cultures by better resembling the in vivo environment of the liver and consequently increase the translational value of the resulting data. In this study, the first stage of hepatic differentiation of human neonatal mesenchymal stem cells (hnMSCs) was performed in 2D monolayer cultures for 17 days. The second stage was performed by either maintaining cells in 2D cultures for an extra 10 days, as control, or alternatively cultured in 3D as self-assembled spheroids or in multicompartment membrane bioreactor system. All systems enabled hnMSC differentiation into HLCs as shown by positive immune staining of hepatic markers CK-18, HNF-4α, albumin, the hepatic transporters OATP-C and MRP-2 as well as drug-metabolizing enzymes like CYP1A2 and CYP3A4. Similarly, all models also displayed relevant glucose, phase I and phase II metabolism, the ability to produce albumin and to convert ammonia into urea. However, EROD activity and urea production were increased in both 3D systems. Moreover, the spheroids revealed higher bupropion conversion, whereas bioreactor showed increased albumin production and capacity to biotransform diclofenac. Additionally, diclofenac resulted in an IC₅₀ value of 1.51 ± 0.05 and 0.98 ± 0.03 in 2D and spheroid cultures, respectively. These data suggest that the 3D models tested improved HLC maturation showing a relevant biotransformation capacity and thus provide more appropriate reliable models for mechanistic studies and more predictive systems for in vitro toxicology applications.

Three-dimensional spheroid cell culture of umbilical cord tissue-derived mesenchymal stromal cells leads to enhanced paracrine induction of wound healing

Introduction

The secretion of trophic factors by mesenchymal stromal cells has gained increased interest given the benefits it may bring to the treatment of a variety of traumatic injuries such as skin wounds. Herein, we report on a three-dimensional culture-based method to improve the paracrine activity of a specific population of umbilical cord tissue-derived mesenchymal stromal cells (UCX®) towards the application of conditioned medium for the treatment of cutaneous wounds.

Methods

A UCX® three-dimensional culture model was developed and characterized with respect to spheroid formation, cell phenotype and cell viability. The secretion by UCX® spheroids of extracellular matrix proteins and trophic factors involved in the wound-healing process was analysed. The skin regenerative potential of UCX® three-dimensional culture-derived conditioned medium (CM3D) was also assessed in vitro and in vivo against UCX® two-dimensional culture-derived conditioned medium (CM2D) using scratch and tubulogenesis assays and a rat wound splinting model, respectively.

Results

UCX® spheroids kept in our three-dimensional system remained viable and multipotent and secreted considerable amounts of vascular endothelial growth factor A, which was undetected in two-dimensional cultures, and higher amounts of matrix metalloproteinase-2, matrix metalloproteinase-9, hepatocyte growth factor, transforming growth factor β1, granulocyte-colony stimulating factor, fibroblast growth factor 2 and interleukin-6, when compared to CM2D. Furthermore, CM3D significantly enhanced elastin production and migration of keratinocytes and fibroblasts in vitro. In turn, tubulogenesis assays revealed increased capillary maturation in the presence of CM3D, as seen by a significant increase in capillary thickness and length when compared to CM2D, and increased branching points and capillary number when compared to basal medium. Finally, CM3D-treated wounds presented signs of faster and better resolution when compared to untreated and CM2D-treated wounds in vivo. Although CM2D proved to be beneficial, CM3D-treated wounds revealed a completely regenerated tissue by day 14 after excisions, with a more mature vascular system already showing glands and hair follicles.

Conclusions

This work unravels an important alternative to the use of cells in the final formulation of advanced therapy medicinal products by providing a proof of concept that a reproducible system for the production of UCX®-conditioned medium can be used to prime a secretome for eventual clinical applications.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0082-5) contains supplementary material, which is available to authorized users.

Role of the Copper(II) Complex Cu[15]pyN5 in Intracellular ROS and Breast Cancer Cell Motility and Invasion

Multiple mechanisms related to metastases undergo redox regulation. Cu[15]pyN5 is a redox-active copper(II) complex previously studied as a chemotherapy sensitizer in mammary cells. The effects of a cotreatment with Cu[15]pyN5 and doxorubicin (dox) were evaluated in two human breast cancer cell lines: MCF7 (low aggressiveness) and MDA-MB-231 (highly aggressive). Cu[15]pyN5 decreased MCF7-directed cell migration. In addition, a cotreatment with dox and Cu[15]pyN5 reduced the proteolytic invasion of MDA-MB-231 cells. Cell detachment was not affected by exposure to these agents. Cu[15]pyN5 and dox significantly increased intracellular ROS in both cell lines. This increase could be at least partially due to H2 O2 accumulation. The combination of Cu[15]pyN5 with dox may be beneficial in breast cancer treatment as it could help reduce cancer cell migration and invasion. Moreover, the ligand [15]pyN5 has a high affinity for copper(II) and displays potential anti-angiogenic properties. Overall, we present a potential drug that might arrest the progression of breast cancer by different and complementary mechanisms.

BioEnterics Intragastric Balloon (BIB): a short-term, double-blind, randomised, controlled, crossover study on weight reduction in morbidly obese patients

BACKGROUND

The BioEnterics Intragastric Balloon (BIB) System in association with restricted diet has been used for the short-term treatment of morbid obesity. Aim of this study was to evaluate the real, short term, efficacy of the BIB for weight reduction in morbidly obese patients by using a prospective, double-blind, randomised, sham-controlled, crossover study.

METHODS

Patients were recruited from January 2003 to December 2003. After selection, they were randomly allocated into two groups: BIB followed by sham procedure after 3 months (Group A), and sham procedure followed by BIB after 3 months (Group B). All endoscopic procedures were performed under unconscious intravenous sedation. The BioEnterics Intragastric Balloon (Inamed Health; Santa Barbara, CA, USA) was filled by using saline (500 ml) and methylene blue (10 ml). Patients were discharged with omeprazole therapy and diet (1000 kcal). Patients were followed up weekly by a physician blinded to randomisation. In both groups mortality, complications, BMI, BMI reduction and %EWL were considered. Data were expressed as mean +/- s.d., except as otherwise indicated. Statistical analysis was performed by means of Student's t-test, Fisher's exact test or chi (2) with Yates correction; P < 0.05 was considered significant.

RESULTS

A total of 32 patients were selected and entered the study (8M/24F; mean age: 36.2 +/- 5.6 years, range 25-50 years; mean BMI 43.7+/-1.5 kg/m(2), range 40-45 kg/m(2); mean %EW: 43.1 +/- 13.1, range: 35-65). All patients completed the study. Mortality was absent. Complications related to endoscopy, balloon placement and removal were absent. Mean time of BIB positioning was 15 +/- 2 min, range 10-20 min. After the first 3 months of the study, in Group A patients the mean BMI significantly (P < 0.001) lowered from 43.5 +/- 1.1 to 38.0 +/- 2.6 kg/m(2), while in Group B patients the decrease was not significant (from 43.6 +/- 1.8 to 43.1 +/- 2.8 kg/m(2)). The mean %EWL was significantly higher in Group A than in Group B (34.0 +/- 4.8 vs 2.1 +/- 1%; P < 0.001). After crossover, at the end of the following 3 months, the BMI lowered from 38.0 +/- 2.6 to 37.1 +/- 3.4 kg/m(2) and from 43.1 +/- 2.8 to 38.8 +/- 3.1 kg/m(2) in Groups A and B, respectively.

CONCLUSIONS

The results of this study show that treatment of obese patients with BioEnterics Intragastric Balloon is a safe and effective procedure. In association with appropriate diet it is significantly effective in weight reduction when compared to sham procedure plus diet. The BIB procedure can play a role in weight reduction in morbidly obese patients or in the preoperative treatment of bariatric patients.

BioEnterics Intragastric Balloon: The Italian Experience with 2,515 Patients

BACKGROUND

The temporary use of the BioEnterics Intragastric Balloon (BIB) in morbidly obesity is increasing worldwide. The aim of this study is the evaluation of the efficacy of this device in a large population, in terms of weight loss and its influence on co-morbidities.

METHODS

Data were retrospectively recruited from the data-base of the Italian Collaborative Study Group for Lap-Band and BIB (GILB). After diagnostic endoscopy, the BIB was positioned and was filled with saline (500-700 ml) and methylene blue (10 ml). Patients were discharged with diet counselling ( approximately 1000 Kcal) and medical therapy. The BIB was removed after 6 months. Positioning and removal were performed under conscious or unconscious sedation. Mortality, complications, BMI, %EWL, BMI loss and co-morbidities were evaluated.

RESULTS

From May 2000 to September 2004, 2,515 patients underwent BIB (722M/1,793F; mean age 38.9+/-14.7, range 12-71; mean BMI 44.4+/-7.8 kg/m(2) ; range 28.0-79.1; and mean excess weight 59.5+/-29.8 kg, range 16-210). BIB positioning was uncomplicated in all but two cases (0.08%) with acute gastric dilation treated conservatively. Overall complication rate was 70/2,515 (2.8%). Gastric perforation occurred in 5 patients (0.19%), 4 of whom had undergone previous gastric surgery: 2 died and 2 were successfully treated by laparoscopic repair after balloon removal. 19 gastric obstructions (0.76%) presented in the first week after positioning and were successfully treated by balloon removal. Balloon rupture (n=9; 0.36%) was not prevalent within any particular period of BIB treatment, and was also treated by BIB removal. Esophagitis (n=32; 1.27%) and gastric ulcer (n=5; 0.2%) presented in patients without a history of peptic disease and were treated conservatively by drugs. Preoperative co-morbidities were diagnosed in 1,394/2,471 patients (56.4%); these resolved in 617/1,394 (44.3%), improved (less pharmacological dosage or shift to other therapies) in 625/1,394 (44.8%), and were unchanged in 152/1,394 (10.9%). After 6 months, mean BMI was 35.4+/-11.8 kg/m(2) (range 24-73) and %EWL was 33.9+/-18.7 (range 0-87). BMI loss was 4.9+/-12.7 kg/m(2) (range 0-25).

CONCLUSIONS

BIB is an effective procedure with satisfactory weight loss and improvement in co-morbidities after 6 months. Previous gastric surgery is a contraindication to BIB placement.