Live simultaneous monitoring of mineral deposition and lipid accumulation in differentiating stem cells

Mesenchymal stem cells (MSCs) are progenitors for bone-forming osteoblasts and lipid-storing adipocytes, two major lineages co-existing in bone marrow. When isolated in vitro, these stem cells recapitulate osteoblast or adipocyte formation if treated with specialised media,modelling how these lineages interact in vivo. Osteogenic differentiation is characterised by mineral deposits accumulating in the extracellular matrix, typically assessed using histological techniques. Adipogenesis occurs with accumulation of intracellular lipids that can be routinely visualised by Oil Red O staining. In both cases, staining requires cell fixation and is thus limited to end-point assessments. Here, a vital staining approach was developed to simultaneously detect mineral deposits and lipid droplets in differentiating cultures. Stem cells induced to differentiate produced mixed cultures containing adipocytes and bone-like nodules, and after two weeks live cultures were incubated with tetracycline hydrochloride and Bodipy to label mineral- and lipid-containing structures, respectively. Fluorescence microscopy showed the simultaneous visualisation of mineralised areas and lipid-filled adipocytes in live cultures. Combined with the nuclear stain Hoechst 33258, this approach further enabled live confocal imaging of adipogenic cells interspersed within the mineralised matrix. This multiplex labelling was repeated at subsequent time-points, demonstrating the potential of this new approach for the real-time high-precision imaging of live stem cells

Porous phosphate-based glass microspheres show biocompatibility, tissue infiltration and osteogenic onset in an ovine bone defect model

Phosphate-based glasses (PBG) are bioactive and fully degradable materials with tailorable degradation rates. PBGs can be produced as porous microspheres through a single-step process, using changes in their formulation and geometry to produce varying pore sizes and interconnectivity for use in a range of applications, including biomedical use. Calcium phosphate PBG have recently been proposed as orthobiologics, based on their in vitro cytocompatibility and ion release profile.In this study, porous microspheres made of two PBG formulations either containing TiO2 (P40Ti) or without (P40) were implanted in vivo in a large animal model of bone defect. The biocompatibility and osteogenic potential of these porous materials were assessed 13 weeks post-implantation in sheep, and compared to empty defects and autologous bone grafts used as negative and positive controls. Histological analysis showed marked differences between the two formulations, as lower trabeculae-like interconnection and higher fatty bone marrow content were observed in the faster degrading P40-implanted defects, whilst the slower degrading P40Ti material promoted dense interconnected tissue. Autologous bone marrow concentrate (BMC) was also incorporated within the P40 and P40Ti microspheres in some defects, however no significant differences were observed in comparison to microspheres implanted alone. Both formulations induced the formation of a collagen-enriched matrix, from 20 % to 40 % for P40 and P40Ti2.5 groups, suggesting commitment towards the bone lineage. With the faster degrading P40 formulation, mineralisation of the tissue matrix was observed both with and without BMC. Some lymphocyte-like cells and foreign body multinucleated giant cells were observed with P40Ti2.5, suggesting this more durable formulation might be linked to an inflammatory response. In conclusion, these first in vivo results indicate that PBG microspheres could be useful candidates for bone repair and regenerative medicine strategies, and highlight the role of material degradation in the process of tissue formation and maturation

The Italian Multicentric Randomized OPTkIMA Trial on Fixed vs Progressive Intermittent TKI Therapy in CML Elderly Patients: 3-Years of Molecular Response and Quality of Life Monitoring After Completing the Treatment Plan

Background: Intermittent treatment with tyrosine kinase inhibitors (TKIs) is an option for elderly chronic myeloid leukemia (CML) patients who are often candidates for life-long treatment. Materials and Methods: The Italian phase III multicentric randomized Optimize TKIs Multiple Approaches (OPTkIMA) study aimed to evaluate if a progressive de-escalation of TKIs is able to maintain the molecular remission (MR)3.0 and to improve Health-Related Quality of Life (HRQoL) in CML elderly patients. Results: A total of 215 patients in stable MR3.0/MR4.0 were randomized to receive an intermittent TKI schedule 1 month ON-1 month OFF for 3 years (FIXED arm; n = 111) vs. a progressive de-escalation TKI dose up to one-third of the starting dose at the 3rd year (PROGRESSIVE arm; n = 104). Two hundred three patients completed the 3rd year of OPTkIMA study. At the last follow-up, MR3.0 loss was 27% vs. 46% (P =.005) in the FIXED vs PROGRESSIVE arm, respectively. None of these patients experienced disease progression. The 3-year probability of maintaining the MR3.0 was 59% vs. 53%, respectively (P =.13). HRQoL globally improved from the baseline to the 3rd year, without any significant difference between the 2 arms. After the 3rd year, the proportion of patients who was address to TKI discontinuation in the 2 arms was 36% (FIXED) vs. 58% (PROGRESSIVE) (P =.03). Conclusions: The intensification of intermittent TKI therapy is associated with a higher incidence of MR3.0 loss, but those patients who maintain the MR3.0 molecular response at the end of the study have been frequently considered eligible for TFR. The HRQoL generally improved during the de-escalation therapy in both randomization arms

CSD 1943259: Experimental Crystal Structure Determination

Related Article: Tiffany M. Smith Pellizzeri, Liurukara D. Sanjeewa, Steven Pellizzeri, Colin D. McMillen, V. Ovidiu Garlea, Feng Ye, Athena S. Sefat, Joseph W. Kolis|2020|Dalton Trans.|49|4323|doi:10.1039/C9DT03389

CSD 1943258: Experimental Crystal Structure Determination

Related Article: Tiffany M. Smith Pellizzeri, Liurukara D. Sanjeewa, Steven Pellizzeri, Colin D. McMillen, V. Ovidiu Garlea, Feng Ye, Athena S. Sefat, Joseph W. Kolis|2020|Dalton Trans.|49|4323|doi:10.1039/C9DT03389

Design Strategies for Luminescent Titanocenes: Improving the Photoluminescence and Photostability of Arylethynyltitanocenes

Complexes that undergo ligand-to-metal charge transfer (LMCT) to d0 metals are of interest as possible photocatalysts. Cp2Ti(C2Ph)2 (where C2Ph = phenylethynyl) was reported to be weakly emissive in room-temperature (RT) fluid solution from its phenylethynyl-to-Ti 3LMCT state but readily photodecomposes. Coordination of CuX between the alkyne ligands to give Cp2Ti(C2Ph)2CuX (X = Cl, Br) has been shown to significantly increase the photostability, but such complexes are not emissive in RT solution. Herein, we investigate whether inhibition of alkyne-Ti-alkyne bond compression might be responsible for the increased photostability of the CuX complexes by investigating the decomposition of a structurally constrained analogue, Cp2Ti(OBET) (OBET = o-bis(ethynyl)tolane). To investigate the mechanism of nonradiative decay from the 3LMCT states in Cp2Ti(C2Ph)2CuX, the photophysical properties were investigated both upon deuteration and upon rigidifying in a poly(methyl methacrylate) film. These investigations suggested that inhibition of structural rearrangement may play a dominant role in increasing emission lifetimes and quantum yields. The bulkier Cp*2Ti(C2Ph)2CuBr was prepared and is emissive at 693 nm in RT THF solution with a photoluminescent quantum yield of 1.3 × 10–3 (τ = 0.18 μs). Time-dependent density functional theory (TDDFT) calculations suggest that emission occurs from a 3LMCT state dominated by Cp*-to-Ti charge transfer