Vascular diseases pose a significant burden on society, mainly due to the lack of effective treatment methods. A major reason for this is the shortcomings of current preclinical model systems. In... Show moreVascular diseases pose a significant burden on society, mainly due to the lack of effective treatment methods. A major reason for this is the shortcomings of current preclinical model systems. In this study, we have taken steps toward developing a more complex and relevant model system for (brain) blood vessels to address this issue. We used human induced pluripotent stem cells (hiPSCs) in the lab as a cellular source to generate the different types of cells needed for stable blood vessels. These cells were then combined in 3D microscopic culture environments (so-called vessel-on-chip systems) to closely mimic physiological conditions. Using this model, we were able to demonstrate specific abnormalities in a hereditary vascular disease, which was not possible with more 'traditional' culture methods. Additionally, we included brain cells to better investigate brain-specific disorders in the future. This work lays the essential foundation for a better understanding and treatment of complex vascular diseases, while potentially reducing the number of animal models needed. Show less
Dutch-type cerebral amyloid angiopathy (D-CAA), also known as hereditary cerebral haemorrhage with amyloidosis-Dutch type (HCHWA-D), is an autosomal dominant disorder caused by a G to C... Show moreDutch-type cerebral amyloid angiopathy (D-CAA), also known as hereditary cerebral haemorrhage with amyloidosis-Dutch type (HCHWA-D), is an autosomal dominant disorder caused by a G to C transversion in codon 693 of the amyloid precursor protein (APP) that results in a Gln-to-Glu amino acid substitution. CRISPRCas9 editing was used for genetic correction of the mutation in a human induced pluripotent stem cell (hiPSC-) line established previously. The isogenic hiPSCs generated showed typical pluripotent stem cell morphology, expressed all markers of undifferentiated state, displayed a normal karyotype and had the capacity to differentiate into the three germ layers. Show less
Functional vasculature is essential for delivering nutrients, oxygen, and cells to the heart and removing waste products. Here, we devel-oped an in vitro vascularized human cardiac microtissue (MT)... Show moreFunctional vasculature is essential for delivering nutrients, oxygen, and cells to the heart and removing waste products. Here, we devel-oped an in vitro vascularized human cardiac microtissue (MT) model based on human induced pluripotent stem cells (hiPSCs) in a micro -fluidic organ-on-chip by coculturing hiPSC-derived, pre-vascularized, cardiac MTs with vascular cells within a fibrin hydrogel. We showed that vascular networks spontaneously formed in and around these MTs and were lumenized and interconnected through anastomosis. Anastomosis was fluid flow dependent: continuous perfusion increased vessel density and thus enhanced the formation of the hybrid vessels. Vascularization further improved endothelial cell (EC)-cardiomyocyte communication via EC-derived paracrine factors, such as nitric oxide, and resulted in an enhanced inflammatory response. The platform sets the stage for studies on how organ-specific EC barriers respond to drugs or inflammatory stimuli. Show less
Orlova, V.V.; Nahon, D.M.; Cochrane, A.; Cao, X.; Freund, C.; Hil, F. van den; ... ; Mummery, C.L. 2022
Hereditary hemorrhagic telangiectasia (HHT) is a genetic disease characterized by weak blood vessels. HHT1 is caused by mutations in the ENDOGLIN (ENG) gene. Here, we generated induced pluripotent... Show moreHereditary hemorrhagic telangiectasia (HHT) is a genetic disease characterized by weak blood vessels. HHT1 is caused by mutations in the ENDOGLIN (ENG) gene. Here, we generated induced pluripotent stem cells (hiPSCs) from a patient with rare mosaic HHT1 with tissues containing both mutant (ENG(c.)(1678C>)(T)) and normal cells, enabling derivation of isogenic diseased and healthy hiPSCs, respectively. We showed reduced ENG expression in HHT1 endothelial cells (HHT1-hiPSC-ECs), reflecting haploinsufficiency. HHT1(c.)(1678C)(>T)-hiPSC-ECs and the healthy isogenic control behaved similarly in two-dimensional (2D) culture, forming functionally indistinguishable vascular networks. However, when grown in 3D organ-on-chip devices under microfluidic flow, lumenized vessels formed in which defective vascular organization was evident: interaction between inner ECs and surrounding pericytes was decreased, and there was evidence for vascular leakage. Organs on chip thus revealed features of HHT in hiPSC-derived blood vessels that were not evident in conventional 2D assays. Show less
