Dissolvable microgel-templated macroporous hydrogels for controlled cell assembly

Mesenchymal stem cells (MSCs)-based therapies have been widely used to promote tissue regeneration and to modulate immune/inflammatory response. The therapeutic potential of MSCs can be further improved by forming multi-cellular spheroids. Meanwhile, hydrogels with macroporous structures are advantageous for improving mass transport properties for the cell-laden matrices. Herein, we report the fabrication of MSC-laden macroporous hydrogel scaffolds through incorporating rapidly dissolvable spherical cell-laden microgels. Dissolvable microgels were fabricated by tandem droplet-microfluidics and thiol-norbornene photopolymerization using a novel fast-degrading macromer poly(ethylene glycol)-norbornene-dopamine (PEGNB-Dopa). The cell-laden microgels were subsequently encapsulated within another bulk hydrogel matrix, whose porous structure was generated efficiently by the rapid degradation of the PEGNB-Dopa microgels. The cytocompatibility of this in situ pore-forming approach was demonstrated with multiple cell types. Furthermore, adjusting the stiffness and cell adhesiveness of the bulk hydrogels afforded the formation of solid cell spheroids or hollow spheres. The assembly of solid or hollow MSC spheroids led to differential activation of AKT pathway. Finally, MSCs solid spheroids formed in situ within the macroporous hydrogels exhibited robust secretion of HGF, VEGF-A, IL-6, IL-8, and TIMP-2. In summary, this platform provides an innovative method for forming cell-laden macroporous hydrogels for a variety of future biomedical applications.

Solid Cell Nests Hyperplasia (Ultimobranchial Body Remnants) of the Thyroid: A Pitfall

Introduction/Objective Solid cell nests (SCN) are small epithelial cell nests interspersed within thyroid parenchyma, resembling squamous/transitional epithelium. SCNs, which are ultimobranchial remnants, are popularly considered pluripotent stem-cells responsible for developing follicular and C-cells. While SCNs are not an uncommon incidental findings in thyroid, solid cell nest hyperplasia is rare. SCNs are often mistaken for benign entities such as C-cell hyperplasia (CCH) or malignant lesions such as papillary thyroid carcinoma (PTC), metastatic squamous cell carcinoma, or medullary thyroid microcarcinoma (MTC). Methods/Case Report To reiterate this diagnostic dilemma, we present a case of a 57-year-old male with a six-year history of Hashimoto thyroiditis and multiple bilateral thyroid nodules. Ultrasonography revealed two nodules, one in each lobe, measuring 2.0x1.9x1.8cm(right) and 1.6x1.5x1.5cm(left). Both were solid, hypoechoic nodules with smooth margins and no echogenic foci. Fine-needle aspiration of right nodule was suspicious for follicular neoplasm, Hürthle- cell type, and the left nodule was atypia of unknown significance. Right-hemithyroidectomy specimen revealed follicular adenoma and oncocytic adenomatous nodules in a background of florid lymphocytic thyroiditis (Hashimoto). In two blocks, small solid nests of cells were identified, largest focus measuring 0.5 cm. The cells were polygonal to epithelioid with moderate amphophilic cytoplasm. Nuclei were centrally located, irregular to oval with occasional grooves. While nests had a squamoid appearance, they did not have intercellular bridges. Although nuclear grooves and evenly dispersed chromatin and chromocenters were noted, they lacked optical clearing or intra-nuclear inclusions characteristic for PTC. Thus, excluding these two possibilities, primary diagnostic considerations were SCN versus CCH. Immunohistochemical analysis showed cells positive for P63 and CK5/6 and negative for PAX-8, TTF-1, thyroglobulin, CEA, and calcitonin. Results (if a Case Study enter NA) NA Conclusion If wrongly diagnosed as CCH, patients may be placed in a high-risk category for possible development of MTC. It is, thus, necessary to be aware of SCN, which can occasionally become hyperplastic, to prevent misdiagnosis.

Thyroid Adenoma of Probable Ultimobranchial Body Origin: A Case Report

Solid cell nests are generally believed to represent remnants of the ultimobranchial body, which can be found in the normal thyroid gland, occasionally associated with other branchial pouch remnants such as salivary gland, cartilage, and adipose tissue. We describe the case of a 44-year-old man incidentally found to have a large tumor in the left lobe of the thyroid. The tumor was a circumscribed growth consisting of distinctly lobulated proliferation of solid to cystic epidermoid cell nests and thyroid follicles in a fibromatous stroma, which merged into abundant adipose tissue and focally myxoid matrix. The solid epidermoid cell nests resembled solid cell nests and exhibited a p63+, GATA3+, galectin-3+, TTF1−, PAX8−, thyroglobulin− phenotypes, while the follicles were p63−, GATA3−, galectin-3−, TTF1+, PAX8+, and thyroglobulin+. RAS mutations were not found. This thyroid tumor may represent a hitherto undescribed “ultimobranchial body adenoma” in human.

Ought to the Changes within the Immunophenotype of Solid Cell Nests (SCNs) and Follicular Cells in Hashimoto’s Thyroiditis be Considered as Premalignant Lesions?

Background: Papillary thyroid carcinoma (PTC) is more frequently reported in patients with Hashimoto’s thyroiditis (HT), which may be associated with the presence of solid cell nests (SCNs) and focal PTC-like nuclear alterations in the thyroid gland. The point of this consideration was to assess the morphological and immunohistochemical features of SCNs and follicular epithelial changes in Vietnamese patients with HT.Materials and methods: Hematoxylin – Eosin and immunohistochemistry were performed on 20 samples of HT patients who underwent thyroidectomy and were diagnosed with Hashimoto's thyroiditis at Military Medical Hospital 103 from 6/2018 to 6/2019. The expression of five markers (P63, Calcitonin, TTF1, CK19, and HBME-1) to be up-regulated in SCNs and follicular epithelial changes were evaluated.Results: 90% of samples had SCNs with an average of 10 SCNs per section. Only type 1 and type 4 of SCNs were presented (85% and 55%, respectively) and all SCNs were composed of main cells (p63-positive). 15 of 18 cases having SCNs possessed nuclear features of PTC. C-cell hyperplasia was found in one case with 20 clusters. All SCNs showed strong staining with CK19 and weak staining with HBME-1. Follicular epithelial changes were Hürthle cell metaplasia, PTC-like nuclear alterations, atypical solid nodules, papillary and glomerular-like forms (40%, 100%, 25%, and 50%, respectively). Follicular cells of glomerular-like forms (new alteration) especially were positive with CK19 (2 + ~ 3+), HBME-1 (1+), and TTF1, while the components in these follicles were negative with CK19, HBME-1, and TTF1. Among PTC-like nuclear alterations, all of the atypical solid nodules related to HT showed markers related to PTC and without SCNs.Conclusions: Increasing the number of SCNs, as well as PTC-like nuclear alterations of main cells in SCNs and follicular epithelial changes, which were co-expressed CK19 and HBME-1, may suggest precancerous changes in Hashimoto's thyroiditis.

Synthesis, Biological Activities and Docking Studies of Novel 4-(Arylaminomethyl)benzamide Derivatives as Potential Tyrosine Kinase Inhibitors

A number of new compounds containing the 4-(aminomethyl)benzamide fragment as a linker were designed and synthesized, and their biological activities were evaluated as potential anticancer agents. The cytotoxicity activity of the designed compounds was studied in two hematological and five solid cell lines in comparison with the reference drugs. Targeted structures against eight receptor tyrosine kinases including EGFR, HER-2, HER-4, IGF1R, InsR, KDR, PDGFRa, and PDGFRb were investigated. The majority of the compounds showed a potent inhibitory activity against the tested kinases. The analogues 11 and 13 with the (trifluoromethyl)benzene ring in the amide or amine moiety of the molecule were proven to be highly potent against EGFR, with 91% and 92% inhibition at 10 nM, respectively. The docking of synthesized target compounds for nine protein kinases contained in the Protein Data Bank (PDB) database was carried out. The molecular modeling results for analogue 10 showed that the use of the 4-(aminomethyl)benzamide as a flexible linker leads to a favorable overall geometry of the molecule, which allows one to bypass the bulk isoleucine residue and provides the necessary binding to the active center of the T315I-mutant Abl (PDB: 3QRJ).

Tubular membranes extended between monolayer cells, from solid spheroids, and from clustered hollow spheroids in Ishikawa endometrial cell cultures can carry chromatin granules and mitonucleons

Membrane tubular extensions, recently recognized an important communication element in mammalian cells are demonstrated to form in Ishikawa endometrial epithelial cells growing in monolayers, and to extend from solid spheroids and from clustered hollow spheroids. Two kinds of chromatin cargoes travel through these tubules. Chromatin granules can pass through an endometrial tubule bridge extending from one monolayer fragment to another. The passage of granules over time from one of the fragments appears to support the self-assembly of nuclei in the other colony fragment. Similarly, in a process detected by observing an open-ended membrane tubule extending from a solid cell spheroid, a nucleus was observed to form over a period of 3 hours. Indications are that chromatin granules such as those observed in the amitotic processes of epithelial dome cell formation and of hollow spheroid cell formation are contributing to the build up of nuclei. Mitonucleons, a transient subcellular organelle consisting of fused mitochondria intimately associated with aggregated chromatin are also observed to pass through tubular membrane extensions. Multiple membrane extensions can be shown to to extend from clusters of unicellular polyploid hollow spheroids whose formation is described for the first time in this paper.

Tubular membranes extended between monolayer cells, from solid spheroids, and from clustered hollow spheroids in Ishikawa endometrial cell cultures can carry chromatin granules and mitonucleons

Membrane tubular extensions, recently recognized an important communication element in mammalian cells are demonstrated to form in Ishikawa endometrial epithelial cells growing in monolayers, and to extend from solid spheroids and from clustered hollow spheroids. Two kinds of chromatin cargoes travel through these tubules. Chromatin granules can pass through an endometrial tubule bridge extending from one monolayer fragment to another. The passage of granules over time from one of the fragments appears to support the self-assembly of nuclei in the other colony fragment. Similarly, in a process detected by observing an open-ended membrane tubule extending from a solid cell spheroid, a nucleus was observed to form over a period of 3 hours. Indications are that chromatin granules such as those observed in the amitotic processes of epithelial dome cell formation and of hollow spheroid cell formation are contributing to the build up of nuclei. Mitonucleons, a transient subcellular organelle consisting of fused mitochondria intimately associated with aggregated chromatin are also observed to pass through tubular membrane extensions. Multiple membrane extensions can be shown to to extend from clusters of unicellular polyploid hollow spheroids whose formation is described for the first time in this paper.