Evidence of a sophisticatedly heterogeneous population of human umbilical vein endothelial cells

TIPE1 accelerates atherogenesis by inducing endothelial dysfunction in response to oxidative stress

Atherosclerosis is an inflammatory disease of the arterial wall, which involves endothelial cells and immune cells. Endothelial dysfunction has been considered an important step in the initiation of the disease. TIPE1 is a newly identified protein of the TIPE family, and plays a vital role in inflammation and tumorigenesis. However, its role in atherogenesis remains unclear. In this study, we demonstrated that TIPE1 promoted atherogenesis by inducing endothelial dysfunction. When human umbilical vein endothelial cells (HUVECs) were exposed to oxidative stress, the level of TIPE1 was significantly up-regulated, and the ROS generation markedly increased in TIPE1 over-expressing HUVECs. As a result, the growth of HUVECs was inhibited, and the apoptosis was enhanced. However, the cell contact ability between HUVECs and THP-1 cells were augmented due to the up-regulation of adhesion molecules such as E-selectin and ICAM-1 induced by TIPE1 overexpression. Importantly, ApoE^-/- mice injected with TIPE1 recombinant lentivirus developed significantly severe atherosclerosis accompanied by hyperglycemia, hypercholesterolemia and increased white blood count. These findings indicated that excessive ROS induced by the overexpression of TIPE1 in endothelial cells accelerated the process of atherogenesis.

A Novel Microscopic Assay Reveals Heterogeneous Regulation of Local Endothelial Barrier Function

Blood vessels are covered with endothelial cells on their inner surfaces, forming a selective and semipermeable barrier between the blood and the underlying tissue. Many pathological processes, such as inflammation or cancer metastasis, are accompanied by an increased vascular permeability. Progress in live cell imaging techniques has recently revealed that the structure of endothelial cell contacts is constantly reorganized and that endothelial junctions display high heterogeneities at a subcellular level even within one cell. Although it is assumed that this dynamic remodeling is associated with a local change in endothelial barrier function, a direct proof is missing mainly because of a lack of appropriate experimental techniques. Here, we describe a new assay to dynamically measure local endothelial barrier function with a lateral resolution of ∼15 μm and a temporal resolution of 1 min. In this setup, fluorescence-labeled molecules are added to the apical compartment of an endothelial monolayer, and the penetration of molecules from the apical to the basal compartment is recorded by total internal reflection fluorescence microscopy utilizing the generated evanescent field. With this technique, we found a remarkable heterogeneity in the local permeability for albumin within confluent endothelial cell layers. In regions with low permeability, stimulation with the proinflammatory agent histamine results in a transient increase in paracellular permeability. The effect showed a high variability along the contact of one individual cell, indicating a local regulation of endothelial barrier function. In regions with high basal permeability, histamine had no obvious effect. In contrast, the barrier-enhancing drug forskolin reduces the permeability for albumin and dextran uniformly along the cell junctions. Because this new approach can be readily combined with other live cell imaging techniques, it will contribute to a better understanding of the mechanisms underlying subcellular junctional reorganization during wound healing, inflammation, and angiogenesis.

Human liver organoids generated with single donor-derived multiple cells rescue mice from acute liver failure

BACKGROUND

Acute liver failure (ALF) is a life-threatening disease with a high mortality rate. However, there are limited treatments or devices available for ALF therapy. Here, we aimed to develop a new strategy for ALF treatment by transplanting functional liver organoids (LOs) generated from single donor-derived human induced pluripotent stem cell (hiPSC) endoderm, endothelial cells (ECs), and mesenchymal cells (MCs).

METHODS

First, we isolated ECs and MCs from a single donor umbilical cord (UC) through enzyme digestion and characterized the UC-ECs and UC-MCs by flow cytometry. Second, using a nonviral reprogramming method, we generated same donor-derived hiPSCs from the UC-ECs and investigated their hepatic differentiation abilities. Finally, we simultaneously plated EC-hiPSC endoderm, UC-ECs, and UC-MCs in a three-dimensional (3D) microwell culture system, and generated single donor cell-derived differentiated LOs for ALF mouse treatment.

RESULTS

We obtained ECs and MCs from a single donor UC with high purity, and these cells provided a multicellular microenvironment that promoted LO differentiation. hiPSCs from the same donor were generated from UC-ECs, and the resultant EC-hiPSCs could be differentiated efficiently into pure definitive endoderm and further into hepatic lineages. Simultaneous plating of EC-hiPSC endoderm, UC-ECs, and UC-MCs in the 3D microwell system generated single donor cell-derived LOs (SDC-LOs) that could be differentiated into functional LOs with enhanced hepatic capacity as compared to that of EC-hiPSC-derived hepatic-like cells. When these functional SDC-LOs were transplanted into the renal subcapsules of ALF mice, they rapidly assumed hepatic functions and improved the survival rate of ALF mice.

CONCLUSION

These results demonstrate that functional LOs generated from single donor cells can improve the condition of ALF mice. Functional SDC-LO transplantation provides a promising novel approach for ALF therapy.

A 15-Year-Old Male Baseball Player With a Mass in the Brachialis Muscle

A 15-year-old boy presented with a mass in his right arm after suffering a minor injury playing baseball. He had been diagnosed with a hematoma. There was no other outstanding medical/surgical history. Magnetic resonance images showed a heterogeneous mass arising from the brachialis muscle that mainly enhanced peripherally with extremely scant internal nodular enhancement. Core needle biopsy cells were positive for CD31 and CD34, markers for atypical endothelial cells, as well as MIB-1 and p53. The final diagnosis was an angiosarcoma of the brachialis muscle. Pediatric angiosarcoma, particularly within deep tissue, is exceedingly rare. Histological and immunohistochemical modalities led to the diagnosis. Magnetic resonance images suggested a mass with a large cystic/hemorrhagic space that could have been misconstrued as a hematoma had there been absolutely no nodular or septal enhancement. The patient underwent neoadjuvant chemotherapy and radiation before undergoing limb-sparing surgery that included resection of the mass with the brachialis muscle and short head of the biceps muscle. Neoadjuvant treatment was deemed successful due to a drastic reduction in the size of the tumor and 95% tumor necrosis. The patient was disease free 2 years postoperatively. There had been no local/systemic recurrences. He was pain free, had normal elbow function, and had returned to playing baseball. It is important to be extremely suspicious when a patient presents with a hemorrhagic, painless, enlarging mass after sustaining minor trauma. A careful and meticulous biopsy must be completed to achieve the correct diagnosis. Magnetic resonance imaging with gadolinium is recommended for evaluation because these masses can be often misinterpreted as hematomas. [Orthopedics. 2016; 39(3):e545-e548.].

Elastofibroma dorsi: a histochemical and immunohistochemical study

Elastofibroma dorsi (ED) is considered a member of a heterogeneous group of benign fibrous (fibroblastic or myofibroblastic) softtissue tumors, frequently localized in the periscapular region in middle aged or older individuals. However, the pathogenesis of ED is still unclear and many authors believe that ED results from a reactive hyperproliferation of fibroblastic tissue, while others suggest that it may be a consequence of a mechanical friction. In our study, we examined 11 cases of ED using histochemical and immunohistochemical methods, in order to extend the knowledge about extracellular matrix composition and histopathogenesis of ED. From the results it appeared that stroma and interspersed spindle cells of ED were positive for both periostin and tenascin-C. Mast cells tryptase-positive were also abundant throughout the lesion. The perivascular distribution of periostin and tenascin-C, associated with the CD34 positivity, suggest that endothelial-mesenchymal transition events can account for neovascularization and production of fibroelastic tissue characteristic of elastofibroma. Our data obtained in endothelial cells cultures demonstrated that elastin production is higher when the status of confluence of the cells is low. So, we can assume that such a phenomenon is a characteristic of mesenchymal/endothelial cells CD34 positive, in which elastin production results to be inversely proportional to the vascular differentiation of cellular elements. In the light of these considerations, we think that a cancerous nature of ED is unlikely. Overall, our study report, for the first time, a detailed description of extracellular matrix composition in ED, suggesting that a mechanical strain-dependent reactivation of periostin and tenascin-C expression, as well as of elastin deposition, could be responsible for development of ED.