Saccular intracranial aneurysm (sIA) rupture is often fatal. Rupture-prone sIA walls are infiltrated by macrophages expressing hemoglobin-receptor CD163, suggesting a role for erythrocyte lysis in the degenerative remodeling predisposing to rupture. We therefore studied erythrocyte remnants in 16 unruptured and 20 ruptured sIA walls using histology and immunohistochemistry. Glycophorin A (GPA), an erythrocyte membrane protein, was present in 34/36 (94%) sIA walls and correlated with loss of αSMA+ cells, reflecting loss of mural smooth muscle cells ([SMCs]; r = -0.592, p < 0.001), wall degeneration (p = 0.008), and rupture (p = 0.005). GPA correlated with high numbers of CD163+ and CD68+ phagocytes (r = 0.65 and r = 0.54, p ≤ 0.001 for both). CD163+ phagocytes were mostly HLA-DR-. Interestingly, single SMCs expressed HLA-DR and also CD163 was expressed in sporadic SMCs, which may reflect their response to hemoglobin accumulation. GPA associated with iron (p = 0.014) was detectable by MRI. An additional 11 sIAs were therefore imaged ex vivo with a 4.7 T MRI prior to histology. In the sIA walls, high GPA and iron accumulation associated with signal intensity in T1-weighted gradient echo MRI. We conclude that accumulation of lysed erythrocytes is a potential driver of inflammatory response in the sIA walls and is associated with the degenerative wall remodeling, thereby predisposing to rupture.

Human mesenchymal stem cells (hMSCs) are used in applications, which may require a large amount of cells; therefore, efficient expansion of the cells is desired. We studied whether TiO2 coating on plastic cell culture dishes could promote proliferation of hMSCs without adverse effects in chondrogenic differentiation. TiO2-films were deposited on polystyrene dishes and glass coverslips using an ultrashort pulsed laser deposition technique. Human MSCs from three donors were expanded on them until 95% confluence, and the cells were evaluated by morphology, immunocytochemistry and quantitative RT-PCR (qRT-PCR). The chondrogenic differentiation in pellets was performed after cultivation on TiO2-coated dishes. Chondrogenesis was evaluated by histological staining of proteoglycans and type II collagen, and qRT-PCR. Human MSC-associated markers STRO-1, CD44, CD90 and CD146 did not change after expansion on TiO2-coated coverslips. However, the cell number after a 48h-culture period was significantly higher on TiO2-coated culture dishes. Importantly, TiO2 coating caused no significant differences in the proteoglycan and type II collagen staining of the pellets, or the expression of chondrocyte-specific genes in the chondrogenesis assay. Thus, the proliferation of hMSCs could be significantly increased when cultured on TiO2-coated dishes without weakening their chondrogenic differentiation capacity. The transparency of TiO2-films allows easy monitoring of the cell growth and morphology under a phase-contrast microscope.

No abstract

The chemical composition and texture of titanium coatings can influence the growth characteristics of the adhered cells. An enhanced proliferation of the human mesenchymal stem cells (hMSCs) would be beneficial. The present study was aimed to investigate whether titanium deposited at different atmospheres would affect the cell growth properties, cellular morphology, and expression of surface markers of hMSCs. Titanium-based coatings were deposited on silicon wafers under oxygen, nitrogen, or argon atmospheres by ultra-short pulsed laser deposition using two different gas pressures followed by heating at 400 °C for 2 h. The characteristics of the coated surfaces were determined via contact angle, zeta potential, and scanning electron microscopy (SEM) techniques. Human MSCs were cultivated on differently coated silicon wafers for 48 h. Subsequently, the cell proliferation rates were analyzed with an MTT assay. The phenotype of hMSCs was checked via immunocytochemical stainings of MSC-associated markers CD73, CD90, and CD105, and the adhesion, spreading, and morphology of hMSCs on coated materials via SEM. The cell proliferation rates of the hMSCs were similar on all coated silicon wafers. The hMSCs retained the MSC phenotype by expressing MSC-associated markers and fibroblast-like morphology with cellular projections. Furthermore, no significant differences could be found in the size of the cells when cultured on all various coated surfaces. In conclusion, despite certain differences in the contact angles and the zeta potentials of various titanium-based coatings, no single coating markedly improved the growth characteristics of hMSCs.