Functional 3-Dimensional Retinal Organoids: Technological Progress and Existing Challenges

Stem cell scientists have developed methods for the self-formation of artificial organs, often referred to as organoids. Organoids can be used as model systems for research in multiple biological disciplines. Yoshiki Sasai’s innovation for deriving mammalian retinal tissue from in vitro stem cells has had a large impact on the study of the biology of vision. New developments in retinal organoid technology provide avenues for in vitro models of human retinal diseases, studies of pathological mechanisms, and development of therapies for retinal degeneration, including electronic retinal implants and gene therapy. Moreover, these innovations have played key roles in establishing models for large-scale drug screening, studying the stages of retinal development, and providing a human model for personalized therapeutic approaches, like cell transplants to replace degenerated retinal cells. Here, we first discuss the importance of human retinal organoids to the biomedical sciences. Then, we review various functional features of retinal organoids that have been developed. Finally, we highlight the current limitations of retinal organoid technologies.

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Human 3-dimensional liver organoids: in vitro model systems to study liver diseases

10.1055/s-0039-3402185 ◽

2020 ◽

Author(s):

H Gaitantzi ◽

C Cai ◽

S Asawa ◽

K Böttcher ◽

M Ebert ◽

...

Keyword(s):

Liver Diseases ◽

In Vitro Model ◽

Model Systems ◽

3 Dimensional ◽

Vitro Model ◽

Liver Organoids

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New Endeavors of (Micro)Tissue Engineering: Cells Tissues Organs on-Chip and Communication Thereof

Cells Tissues Organs ◽

10.1159/000516356 ◽

2021 ◽

pp. 1-15

Author(s):

Haysam M.M.A.M. Ahmed ◽

Liliana S. Moreira Teixeira

Keyword(s):

Tissue Engineering ◽

Food Additives ◽

Market Potential ◽

Model Systems ◽

Human Model ◽

Human Stem Cells ◽

Animal Testing ◽

Preclinical Research ◽

On Chip

The development of new therapies is tremendously hampered by the insufficient availability of human model systems suitable for preclinical research on disease target identification, drug efficacy, and toxicity. Thus, drug failures in clinical trials are too common and too costly. Animal models or standard 2D in vitro tissue cultures, regardless of whether they are human based, are regularly not representative of specific human responses. Approaching near human tissues and organs test systems is the key goal of organs-on-chips (OoC) technology. This technology is currently showing its potential to reduce both drug development costs and time-to-market, while critically lessening animal testing. OoC are based on human (stem) cells, potentially derived from healthy or disease-affected patients, thereby amenable to personalized therapy development. It is noteworthy that the OoC market potential goes beyond pharma, with the possibility to test cosmetics, food additives, or environmental contaminants. This (micro)tissue engineering-based technology is highly multidisciplinary, combining fields such as (developmental) biology, (bio)materials, microfluidics, sensors, and imaging. The enormous potential of OoC is currently facing an exciting new challenge: emulating cross-communication between tissues and organs, to simulate more complex systemic responses, such as in cancer, or restricted to confined environments, as occurs in osteoarthritis. This review describes key examples of multiorgan/tissue-on-chip approaches, or linked organs/tissues-on-chip, focusing on challenges and promising new avenues of this advanced model system. Additionally, major emphasis is given to the translation of established tissue engineering approaches, bottom up and top down, towards the development of more complex, robust, and representative (multi)organ/tissue-on-chip approaches.

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Unbiased in vivo preclinical evaluation of anticancer drugs identifies effective therapy for the treatment of pancreatic adenocarcinoma

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1920240117 ◽

2020 ◽

Vol 117 (48) ◽

pp. 30670-30678

Author(s):

Olivera Grbovic-Huezo ◽

Kenneth L. Pitter ◽

Nicolas Lecomte ◽

Joseph Saglimbeni ◽

Gokce Askan ◽

...

Keyword(s):

Large Scale ◽

Single Agent ◽

Model Systems ◽

Ductal Adenocarcinoma ◽

In Vivo Model ◽

Cancer Therapies ◽

Hsp90 Inhibition ◽

Dismal Prognosis

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at an advanced stage, which limits surgical options and portends a dismal prognosis. Current oncologic PDAC therapies confer marginal benefit and, thus, a significant unmet clinical need exists for new therapeutic strategies. To identify effective PDAC therapies, we leveraged a syngeneic orthotopic PDAC transplant mouse model to perform a large-scale, in vivo screen of 16 single-agent and 41 two-drug targeted therapy combinations in mice. Among 57 drug conditions screened, combined inhibition of heat shock protein (Hsp)-90 and MEK was found to produce robust suppression of tumor growth, leading to an 80% increase in the survival of PDAC-bearing mice with no significant toxicity. Mechanistically, we observed that single-agent MEK inhibition led to compensatory activation of resistance pathways, including components of the PI3K/AKT/mTOR signaling axis, which was overcome with the addition of HSP90 inhibition. The combination of HSP90(i) + MEK(i) was also active in vitro in established human PDAC cell lines and in vivo in patient-derived organoid PDAC transplant models. These findings encourage the clinical development of HSP90(i) + MEK(i) combination therapy and highlight the power of clinically relevant in vivo model systems for identifying cancer therapies.

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Detection of risk of cancer to man

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1979.0052 ◽

1979 ◽

Vol 205 (1158) ◽

pp. 111-120 ◽

Cited By ~ 16

Keyword(s):

Large Scale ◽

Human Cancer ◽

Environmental Pollutants ◽

Model Systems ◽

Fourth Power ◽

Percentage Increase ◽

Direct Estimate ◽

Human Carcinogenesis ◽

Risk Of Cancer

Epidemiology can pick out large-scale determinants of human cancer, such as smoking. Also, epidemiology can pick out carcinogens such as asbestos to which groups of perhaps a few hundred or a few thousand workers have been heavily exposed for decades. However, if highly exposed groups cannot be studied then epidemiology cannot recognize carcinogens which, although perhaps widely distributed, produce only a small percentage increase in particular cancers. Almost all of the environmental pollutants that can affect human cancer incidence will do so only to a very minor extent, at the levels to which we are currently exposed. For this reason, and also because it is often difficult to define an exposed and an unexposed group which do not differ in other ways as well, it will almost always be impossible to do anything epidemiologically except to set a very crude upper limit on their likely hazards. The only way, therefore, to get any direct estimate of these hazards is by laboratory studies of the effects of high doses on various model systems. For this and for other reasons, it would be highly desirable to have good laboratory models for human carcinogenesis. The characteristics required of satisfactory laboratory systems are reviewed, and it is argued that systematic errors may arise unless one studies epithelial cells from large, long-lived species under conditions of chronic, low-dose exposure to noxious test agents in conjunction with standard chronic doses of agents which may be synergistic with the test agents. (Carcinogenic mutagens may be synergistic with carcinogenic non-mutagens.) For reasons of expense and speed, such studies must be done in vitro . If such in-vitro systems can be developed, either by using tissue explants or cell cultures, an important criterion which they will have to satisfy to be trusted will be that under chronic exposure the rate of transformation should be proportional to something like the fourth power of exposure duration. This paper chiefly reviews the reasons for choosing these specifications for a trustworthy in-vitro model for human carcinogenesis.

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Pathogenesis of paclitaxel-induced peripheral neuropathy: A current review of in vitro and in vivo findings using rodent and human model systems

Experimental Neurology ◽

10.1016/j.expneurol.2019.113121 ◽

2020 ◽

Vol 324 ◽

pp. 113121 ◽

Cited By ~ 15

Author(s):

Nathan P. Staff ◽

Jill C. Fehrenbacher ◽

Martial Caillaud ◽

M. Imad Damaj ◽

Rosalind A. Segal ◽

...

Keyword(s):

Peripheral Neuropathy ◽

Model Systems ◽

Human Model ◽

Current Review ◽

A Current

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Microvascularized tumor organoids-on-chips: advancing preclinical drug screening with pathophysiological relevance

Nano Convergence ◽

10.1186/s40580-021-00261-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Jungeun Lim ◽

Hanna Ching ◽

Jeong-Kee Yoon ◽

Noo Li Jeon ◽

YongTae Kim

Keyword(s):

Large Scale ◽

Recent Progress ◽

Personalized Cancer Medicine ◽

Recent Developments ◽

Functional Features ◽

Cancer Medicine ◽

Potential Strategy ◽

Personalized Cancer ◽

Tumor Organoids

AbstractRecent developments of organoids engineering and organ-on-a-chip microfluidic technologies have enabled the recapitulation of the major functions and architectures of microscale human tissue, including tumor pathophysiology. Nevertheless, there remain challenges in recapitulating the complexity and heterogeneity of tumor microenvironment. The integration of these engineering technologies suggests a potential strategy to overcome the limitations in reconstituting the perfusable microvascular system of large-scale tumors conserving their key functional features. Here, we review the recent progress of in vitro tumor-on-a-chip microfluidic technologies, focusing on the reconstruction of microvascularized organoid models to suggest a better platform for personalized cancer medicine.

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Assessment of Ocriplasmin Effects on the Vitreoretinal Compartment in Porcine and Human Model Systems

Journal of Ophthalmology ◽

10.1155/2017/2060765 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

Bart Jonckx ◽

Michael Porcu ◽

Aurelie Candi ◽

Isabelle Etienne ◽

Philippe Barbeaux ◽

...

Keyword(s):

Posterior Vitreous Detachment ◽

Subretinal Fluid ◽

Model Systems ◽

Human Model ◽

Blood Retinal Barrier ◽

Barrier Permeability ◽

Cell Type Specific ◽

Insight Into

Ocriplasmin (Jetrea®) is a recombinant protease used to treat vitreomacular traction. To gain insight into vitreoretinal observations reported after ocriplasmin treatment, we have developed anin vivoporcine ocriplasmin-induced posterior vitreous detachment (PVD) model in which we investigated vitreoretinal tissues by optical coherence tomography, histology, and cytokine profiling. Eight weeks postinjection, ocriplasmin yielded PVD in 82% of eyes. Subretinal fluid (85%) and vitreous hyperreflective spots (45%) were resolved by week 3. Histological analysis of extracellular matrix (ECM) proteins such as laminin, fibronectin, and collagen IV indicated no retinal ocriplasmin-induced ECM distribution changes. Retinal morphology was unaffected in all eyes. Cytokine profiles of ocriplasmin-treated eyes were not different from vehicle. In cell-based electrical resistance assays, blood-retinal barrier permeability was altered by ocriplasmin concentrations of 6 μg/mL and higher, with all effects being nontoxic, cell-type specific, and reversible. Ocriplasmin was actively taken up by RPE and Müller cells, and our data suggest both lysosomal and transcellular clearance routes for ocriplasmin. In conclusion, transient hyperreflective spots and fluid in a porcine ocriplasmin-induced PVD model did not correlate with retinal ECM rearrangement nor inflammation. Reversiblein vitroeffects on blood-retinal barrier permeability provide grounds for a hypothesis on the mechanisms behind transient subretinal fluid observed in ocriplasmin-treated patients.

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Recent progress in translational engineered in vitro models of the central nervous system

Brain ◽

10.1093/brain/awaa268 ◽

2020 ◽

Vol 143 (11) ◽

pp. 3181-3213 ◽

Cited By ~ 1

Author(s):

Polyxeni Nikolakopoulou ◽

Rossana Rauti ◽

Dimitrios Voulgaris ◽

Iftach Shlomy ◽

Ben M Maoz ◽

...

Keyword(s):

Large Scale ◽

Induced Pluripotent Stem Cell ◽

In Vitro Models ◽

Model Systems ◽

Success Rates ◽

Recent Developments ◽

Practical Guidelines ◽

Organ On A Chip ◽

Induced Pluripotent

Abstract The complexity of the human brain poses a substantial challenge for the development of models of the CNS. Current animal models lack many essential human characteristics (in addition to raising operational challenges and ethical concerns), and conventional in vitro models, in turn, are limited in their capacity to provide information regarding many functional and systemic responses. Indeed, these challenges may underlie the notoriously low success rates of CNS drug development efforts. During the past 5 years, there has been a leap in the complexity and functionality of in vitro systems of the CNS, which have the potential to overcome many of the limitations of traditional model systems. The availability of human-derived induced pluripotent stem cell technology has further increased the translational potential of these systems. Yet, the adoption of state-of-the-art in vitro platforms within the CNS research community is limited. This may be attributable to the high costs or the immaturity of the systems. Nevertheless, the costs of fabrication have decreased, and there are tremendous ongoing efforts to improve the quality of cell differentiation. Herein, we aim to raise awareness of the capabilities and accessibility of advanced in vitro CNS technologies. We provide an overview of some of the main recent developments (since 2015) in in vitro CNS models. In particular, we focus on engineered in vitro models based on cell culture systems combined with microfluidic platforms (e.g. ‘organ-on-a-chip’ systems). We delve into the fundamental principles underlying these systems and review several applications of these platforms for the study of the CNS in health and disease. Our discussion further addresses the challenges that hinder the implementation of advanced in vitro platforms in personalized medicine or in large-scale industrial settings, and outlines the existing differentiation protocols and industrial cell sources. We conclude by providing practical guidelines for laboratories that are considering adopting organ-on-a-chip technologies.

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Effects of early geometric confinement on the transcriptomic profile of human cerebral organoids

10.1101/2021.02.18.431674 ◽

2021 ◽

Author(s):

Dilara Sen ◽

Alexis Voulgaropoulos ◽

Albert J. Keung

Keyword(s):

Stem Cell Differentiation ◽

Cell Types ◽

Brain Regions ◽

Embryoid Bodies ◽

Model Systems ◽

Human Model ◽

Spatial Factors ◽

Neural Lineage

ABSTRACTBackgroundBiophysical factors such as shape and mechanical forces are known to play crucial roles in stem cell differentiation, embryogenesis and neurodevelopment. However, the complexity and experimental challenges capturing such early stages of development, and ethical concerns associated with human embryo and fetal research, limit our understanding of how these factors affect human brain organogenesis. Human cerebral organoids (hCO) are attractive models due to their ability to model important brain regions and transcriptomics of early in vivo brain development. Furthermore, they provide three-dimensional environments that better mimic the in vivo environment. To date, they have been used to understand the effects of genetics and soluble factors on neurodevelopment. Establishing links between spatial factors and hCO development will require the development of new approaches.ResultsHere, we investigated the effects of early geometric confinements on transcriptomic changes during hCO differentiation. Using a custom and tunable agarose microwell platform we generated embryoid bodies (EB) of diverse shapes and then further differentiated those EBs to whole brain hCOs. Our results showed that the microwells did not have negative gross impacts on the ability of the hCOs to differentiate generally towards neural fates, and there were clear shape dependent effects on neural lineage specification. In particular, we observed that non-spherical shapes showed signs of altered neurodevelopmental kinetics and favored the development of medial ganglionic eminence-associated brain regions and cell types over cortical regions.ConclusionsThe findings presented here suggest a role for spatial factors in brain region specification during hCO development. Understanding these spatial patterning factors will not only improve understanding of in vivo development and differentiation, but also provide important handles with which to advance and improve control over human model systems for in vitro applications.

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DoE Analysis of Approaches for Hydrogel Microbeads’ Preparation by Millifluidic Methods

Micromachines ◽

10.3390/mi11111007 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1007

Author(s):

Anna Nastruzzi ◽

Gabriele Pitingolo ◽

Giovanni Luca ◽

Claudio Nastruzzi

Keyword(s):

Mass Production ◽

Large Scale ◽

Single Cells ◽

Great Promise ◽

Scale Production ◽

Large Scale Production ◽

Different Types ◽

Cell Transplants

Hydrogel microbeads hold great promise for immune-protective cell transplants and in vitro studies. Millifluidic generation of hydrogel microbeads is a highly efficient and reproducible approach enabling a mass production. This paper illustrates the preparation and characterization of highly controlled and reproducible microbeads made by different types of hydrogel using millifluidic approaches. The optimization of the process was made by a design of experiments (DoE) approach. The microbeads’ large-scale production can be potentially used for single cells or clusters encapsulation.

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