PURPOSE: To investigate the effect and dose response of very small iron oxide particles (VSOP) labeling of human chondrocytes for long-term in vitro MRI tracking. MATERIALS AND METHODS: Chondrocytes were isolated from cartilage biopsies from four patients. The cells for the dose-response study were labeled with 25, 50, or 100 μg/mL VSOP. Quantitative gene expression and cellular proliferation were compared with unlabeled controls at day 1, 3, and 7. The cells suited for MRI tracking were labeled with 50 μg/mL VSOP and embedded in alginate beads, followed by MRI (using T2-weighted sequences) at day 0, 1, 3, 7, 14, 21, 28, and histology was performed at each time-point. RESULTS: Histology revealed that VSOP particles were intracellularly confined at all time-points, whereas no extracellular VSOPs were observed. A mean reduction in T2-value of 25.1 ms (±SD 3.5 ms) was found on T2-maps. The chondrocyte-specific genes aggrecan, collagen type 2, and sox9 were all affected by labeling, the two latter in a dose-dependent manner. VSOPs had no effect on proliferation. CONCLUSION: VSOP labeling of chondrocytes affected gene expression but not proliferation. The labeled chondrocytes could be recognized by MRI for 4 weeks without significant changes in the T2 relaxation time.
PURPOSE: To investigate the effect and dose response of very small iron oxide particles (VSOP) labeling of human chondrocytes for long-term in vitro MRI tracking. MATERIALS AND METHODS: Chondrocytes were isolated from cartilage biopsies from four patients. The cells for the dose-response study were labeled with 25, 50, or 100 μg/mL VSOP. Quantitative gene expression and cellular proliferation were compared with unlabeled controls at day 1, 3, and 7. The cells suited for MRI tracking were labeled with 50 μg/mL VSOP and embedded in alginate beads, followed by MRI (using T2-weighted sequences) at day 0, 1, 3, 7, 14, 21, 28, and histology was performed at each time-point. RESULTS: Histology revealed that VSOP particles were intracellularly confined at all time-points, whereas no extracellular VSOPs were observed. A mean reduction in T2-value of 25.1 ms (±SD 3.5 ms) was found on T2-maps. The chondrocyte-specific genes aggrecan, collagen type 2, and sox9 were all affected by labeling, the two latter in a dose-dependent manner. VSOPs had no effect on proliferation. CONCLUSION: VSOP labeling of chondrocytes affected gene expression but not proliferation. The labeled chondrocytes could be recognized by MRI for 4 weeks without significant changes in the T2 relaxation time.
Authors: Alexandra Scharf; Shannon P Holmes; Merrilee Thoresen; Jennifer Mumaw; Alaina Stumpf; John Peroni Journal: Stem Cells Int Date: 2016-09-26 Impact factor: 5.443
Authors: Katrin Radeloff; Mario Ramos Tirado; Daniel Haddad; Kathrin Breuer; Jana Müller; Sabine Hochmuth; Stephan Hackenberg; Agmal Scherzad; Norbert Kleinsasser; Andreas Radeloff Journal: Materials (Basel) Date: 2021-01-07 Impact factor: 3.623