Page 154 - Cellular Imaging in Regenerative Medicine, Cancer and Osteoarthritis

Chapter 7
Figure 2 Binding of [111In]In-DOTA-TATE to SSTR2 on human monocyte-derived macrophages.
Binding of [111In]In-DOTA-TATE (as a measure of SSTR2 presence) to M(IFNγ+TNFα) in kBq/1e5 cells. Blocking of the specific binding to SSTR2 was performed with excess of unlabeled DOTA-TATE. Data is presented as mean + SD.
Autoradiography analysis of binding of the radiolabeled tracer [111In]In-DOTA- JR11 showed regions with higher signal intensities corresponding to cell dense areas on H&E-stained sections (Fig. 3A and 3B). The intensity of the autoradiography signal was significantly increased up to 3.1 times (average 1.6; range 0.5-3.1; p<0.05) in IFNγ+TNFα-stimulated synovial tissue relative to unstimulated synovial tissue (Fig. 3C).
Presence of macrophages during experimental OA
To establish the relevance of SSTR2 tracer as a marker for pro-inflammatory macrophages in vivo, presence of macrophages and uptake of SSTR2 tracer was studied in a mouse DMM model for OA over time.
From knees, which were harvested eight weeks after induction of OA by DMM, three consecutive thionin-stained sections of the medial femoral condyle and medial tibial plateau were evaluated. The summed OARSI scores for three DMM knees were: 2.5, 4.0, and 10.5. Osteophytes were present in all DMM knees. Control knees did not have any signs of cartilage degradation (OARSI score 0 for all knees) and did not present any indications of osteophyte formation (Fig. 4).
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