The vascular and the nervous system are responsible for oxygen, nutrient, and information transfer and thereby constitute highly important communication systems in higher organisms. These functional ...similarities are reflected at the anatomical, cellular, and molecular levels, where common developmental principles and mutual crosstalks have evolved to coordinate their action. This resemblance of the two systems at different levels of complexity has been termed the “neurovascular link.” Most of the evidence demonstrating neurovascular interactions derives from studies outside the CNS and from the CNS tissue of the retina. However, little is known about the specific properties of the neurovascular link in the brain. Here, we focus on regulatory effects of molecules involved in the neurovascular link on angiogenesis in the periphery and in the brain and distinguish between general and CNS-specific cues for angiogenesis. Moreover, we discuss the emerging molecular interactions of these angiogenic cues with the VEGF-VEGFR-Delta-like ligand 4 (Dll4)-Jagged-Notch pathway.
The review by Wälchli et al. describes how the molecules involved in the neurovascular link regulate angiogenesis and endothelial tip cells in the brain and the periphery and discusses the molecular interactions of these cues with the VEGF-VEGFR-Delta-like-ligand-4 (Dll4)-Jagged-Notch pathway.
In regenerative medicine, adult stem cells are the most promising cell types for cell-based therapies. As a new source for multipotent stem cells, human adipose tissue has been introduced. These so ...called adipose tissue-derived stem cells (ADSCs) are considered to be ideal for application in regenerative therapies. Their main advantage over mesenchymal stem cells derived from other sources, e.g. from bone marrow, is that they can be easily and repeatable harvested using minimally invasive techniques with low morbidity. ADSCs are multipotent and can differentiate into various cell types of the tri-germ lineages, including e.g. osteocytes, adipocytes, neural cells, vascular endothelial cells, cardiomyocytes, pancreatic β-cells, and hepatocytes. Interestingly, ADSCs are characterized by immunosuppressive properties and low immunogenicity. Their secretion of trophic factors enforces the therapeutic and regenerative outcome in a wide range of applications. Taken together, these particular attributes of ADSCs make them highly relevant for clinical applications. Consequently, the therapeutic potential of ADSCs is enormous. Therefore, this review will provide a brief overview of the possible therapeutic applications of ADSCs with regard to their differentiation potential into the tri-germ lineages. Moreover, the relevant advancements made in the field, regulatory aspects as well as other challenges and obstacles will be highlighted.
Human Cardiac Organoids for Disease Modeling Nugraha, Bramasta; Buono, Michele F.; Boehmer, Lisa ...
Clinical pharmacology and therapeutics,
January 2019, 2019-Jan, 2019-01-00, 20190101, Letnik:
105, Številka:
1
Journal Article
Recenzirano
Human cardiac drug discovery and disease modeling face challenges in recapitulating cellular complexity and animal‐to‐human translation due to the limitations of conventional 2D cell culture and ...animal models. The development of human cardiac organoid technologies could help in stimulating and maintaining differentiated cell functions for extended periods of time. By closely mimicking in vivo organ functions in vitro they could thereby help in overcoming the obstacles mentioned above. Through the construction of human cardiac organoids from pluripotent stem cell–derived cells, derived from patients with specific known genotypes and phenotypes, more complex and robust in vitro tools have recently become available for disease modeling. In this review, we will describe the relevance and importance of evolving organoid platforms in disease biology. We further provide examples of cardiac organoid platforms, which may lead the way toward future personalized medicine and drug discovery.
Upon implanting tissue-engineered heart valves (TEHVs), blood-derived macrophages are believed to orchestrate the remodeling process. They initiate the immune response and mediate the remodeling of ...the TEHV, essential for the valve's functionality. The exact role of another macrophage type, the tissue-resident macrophages (TRMs), has not been yet elucidated even though they maintain the homeostasis of native tissues. Here, we characterized the response of hTRM-like cells in contact with a human tissue engineered matrix (hTEM). HTEMs comprised intracellular peptides with potentially immunogenic properties in their ECM proteome. Human iPSC-derived macrophages (iMφs) could represent hTRM-like cells in vitro and circumvent the scarcity of human donor material. iMφs were derived and after stimulation they demonstrated polarization towards non-/inflammatory states. Next, they responded with increased IL-6/IL-1β secretion in separate 3/7-day cultures with longer production-time-hTEMs. We demonstrated that iMφs are a potential model for TRM-like cells for the assessment of hTEM immunocompatibility. They adopt distinct pro- and anti-inflammatory phenotypes, and both IL-6 and IL-1β secretion depends on hTEM composition. IL-6 provided the highest sensitivity to measure iMφs pro-inflammatory response. This platform could facilitate the in vitro immunocompatibility assessment of hTEMs and thereby showcase a potential way to achieve safer clinical translation of TEHVs.
Objectives This study sought to evaluate long-term in vivo functionality, host cell repopulation, and remodeling of “off-the-shelf” tissue engineered transcatheter homologous heart valves. Background ...Transcatheter valve implantation has emerged as a valid alternative to conventional surgery, in particular for elderly high-risk patients. However, currently used bioprosthetic transcatheter valves are prone to progressive dysfunctional degeneration, limiting their use in younger patients. To overcome these limitations, the concept of tissue engineered heart valves with self-repair capacity has been introduced as next-generation technology. Methods In vivo functionality, host cell repopulation, and matrix remodeling of homologous transcatheter tissue-engineered heart valves (TEHVs) was evaluated up to 24 weeks as pulmonary valve replacements (transapical access) in sheep (n = 12). As a control, tissue composition and structure were analyzed in identical not implanted TEHVs (n = 5). Results Transcatheter implantation was successful in all animals. Valve functionality was excellent displaying sufficient leaflet motion and coaptation with only minor paravalvular leakage in some animals. Mild central regurgitation was detected after 8 weeks, increasing to moderate after 24 weeks, correlating to a compromised leaflet coaptation. Mean and peak transvalvular pressure gradients were 4.4 ± 1.6 mm Hg and 9.7 ± 3.0 mm Hg, respectively. Significant matrix remodeling was observed in the entire valve and corresponded with the rate of host cell repopulation. Conclusions For the first time, the feasibility and long-term functionality of transcatheter-based homologous off-the-shelf tissue engineered heart valves are demonstrated in a relevant pre-clinical model. Such engineered heart valves may represent an interesting alternative to current prostheses because of their rapid cellular repopulation, tissue remodeling, and therewith self-repair capacity. The concept of homologous off-the-shelf tissue engineered heart valves may therefore substantially simplify previous tissue engineering concepts toward clinical translation.
Wounds in the fetus can heal without scarring. Consequently, biomaterials that attempt to recapitulate the biophysical and biochemical properties of fetal skin have emerged as promising ...pro-regenerative strategies. The extracellular matrix (ECM) protein fibronectin (Fn) in particular is believed to play a crucial role in directing this regenerative phenotype. Accordingly, Fn has been implicated in numerous wound healing studies, yet remains untested in its fibrillar conformation as found in fetal skin. Here, we show that high extensional (∼1.2 ×105 s−1) and shear (∼3 ×105 s−1) strain rates in rotary jet spinning (RJS) can drive high throughput Fn fibrillogenesis (∼10 mL/min), thus producing nanofiber scaffolds that are used to effectively enhance wound healing. When tested on a full-thickness wound mouse model, Fn nanofiber dressings not only accelerated wound closure, but also significantly improved tissue restoration, recovering dermal and epidermal structures as well as skin appendages and adipose tissue. Together, these results suggest that bioprotein nanofiber fabrication via RJS could set a new paradigm for enhancing wound healing and may thus find use in a variety of regenerative medicine applications.
The pathogenesis of atherosclerosis involves dysfunctions of vascular endothelial cells and smooth muscle cells as well as blood borne inflammatory cells such as monocyte-derived macrophages. In ...vitro experiments towards a better understanding of these dysfunctions are typically performed in two-dimensional cell culture systems. However, these models lack both the three-dimensional structure and the physiological pulsatile flow conditions of native arteries. We here describe the development and initial characterization of a tissue engineered artery equivalent, which is composed of human primary endothelial and smooth muscle cells and is exposed to flow in vitro. Histological analyses showed formation of a dense tissue composed of a tight monolayer of endothelial cells supported by a basement membrane and multiple smooth muscle cell layers. Both low (LDL) and high density lipoproteins (HDL) perfused through the artery equivalent were recovered both within endothelial cells and in the sub-endothelial intima. After activation of the endothelium with either tumour necrosis factor alpha (TNFα) or LDL, monocytes circulated through the model were found to adhere to the activated endothelium and to transmigrate into the intima. In conclusion, the described tissue engineered human artery equivalent model represents a significant step towards a relevant in vitro platform for the systematic assessment of pathogenic processes in atherosclerosis independently of any systemic factors.
Genetic cardiomyopathies are characterized by changes in the function and structure of the myocardium. The development of a novel in vitro model could help to better emulate healthy and diseased ...human heart conditions and may improve the understanding of disease mechanisms. In this study, for the first time, we demonstrated the generation of cardiac organoids using a triculture approach of human induced pluripotent stem-cell-derived cardiomyocytes (hiPS-CMs)-from healthy subjects and cardiomyopathy patients-human cardiac microvascular endothelial cells (HCMECs) and human cardiac fibroblasts (HCFs). We assessed the organoids' suitability as a 3D cellular model for the representation of phenotypical features of healthy and cardiomyopathic hearts. We observed clear differences in structure and beating behavior between the organoid groups, depending on the type of hiPS-CMs (healthy versus cardiomyopathic) used. Organoids may thus prove a promising tool for the design and testing of patient-specific treatments as well as provide a platform for safer and more efficacious drug development.
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