MAPC transplantation confers a more durable benefit than AC133+ cell transplantation

There is a need for comparative studies to determine which cell types are better candidates to remedy ischemia. Here, we compared human AC133+ cells and Multipotent Adult Progenitor Cells (hMAPC) in a mouse model reminiscent of critical limb ischemia. hMAPC or hAC133+ cell transplantation induced a significant improvement in tissue perfusion (measured by microPET) 15 days post-transplantation compared to controls. This improvement persisted for 30 days in hMAPC-treated but not in hAC133+-injected animals. While transplantation of hAC133+ cells promoted capillary growth, hMAPC transplantation also induced collateral expansion, decreased muscle necrosis/fibrosis and improved muscle regeneration. Incorporation of differentiated hAC133+ or hMAPC progeny into new vessels was limited, however, a paracrine angio/arteriogenic effect was demonstrated in animals treated with hMAPC. Accordingly, hMAPC-, but not hAC133+-conditioned media, stimulated vascular cell proliferation and prevented myoblast, endothelial and smooth muscle cell apoptosis in vitro. Our study suggests that although hAC133+ cell and hMAPC transplantation bothcontribute to vascular regeneration in ischemic limbs, hMAPC exert a more robust effect through trophic mechanisms, which translated into collateral and muscle fiber regeneration. This, in turn, conferred tissue protection and regeneration with longer-term functional improvement

Radiolabeled risperidone microSPECT/CT imaging for intranasal implant studies development

The use of intranasal implantable drug delivery systems has many potential advantages for the treatment of different diseases, as they can provide sustained drug delivery, improving patient compliance. We describe a novel proof-of-concept methodological study using intranasal implants with radiolabeled risperidone (RISP) as a model molecule. This novel approach could provide very valuable data for the design and optimization of intranasal implants for sustained drug delivery. RISP was radiolabeled with 125I by solid supported direct halogen electrophilic substitution and added to a poly(lactide-co-glycolide) (PLGA; 75/25 D,L-Lactide/glycolide ratio) solution that was casted on top of 3D-printed silicone molds adapted for intranasal administration to laboratory animals. Implants were intranasally administered to rats, and radiolabeled RISP release followed for 4 weeks by in vivo non-invasive quantitative microSPECT/CT imaging. Percentage release data were compared with in vitro ones using radiolabeled implants containing either 125I-RISP or [125I]INa and also by HPLC measurement of drug release. Implants remained in the nasal cavity for up to a month and were slowly and steadily dissolved. All methods showed a fast release of the lipophilic drug in the first days with a steadier increase to reach a plateau after approximately 5 days. The release of [125I]I- took place at a much slower rate. We herein demonstrate the feasibility of this experimental approach to obtain high-resolution, non-invasive quantitative images of the release of the radiolabeled drug, providing valuable information for improved pharmaceutical development of intranasal implants

MAPC transplantation confers a more durable benefit than AC133+ cell transplantation

There is a need for comparative studies to determine which cell types are better candidates to remedy ischemia. Here, we compared human AC133+ cells and Multipotent Adult Progenitor Cells (hMAPC) in a mouse model reminiscent of critical limb ischemia. hMAPC or hAC133+ cell transplantation induced a significant improvement in tissue perfusion (measured by microPET) 15 days post-transplantation compared to controls. This improvement persisted for 30 days in hMAPC-treated but not in hAC133+-injected animals. While transplantation of hAC133+ cells promoted capillary growth, hMAPC transplantation also induced collateral expansion, decreased muscle necrosis/fibrosis and improved muscle regeneration. Incorporation of differentiated hAC133+ or hMAPC progeny into new vessels was limited, however, a paracrine angio/arteriogenic effect was demonstrated in animals treated with hMAPC. Accordingly, hMAPC-, but not hAC133+-conditioned media, stimulated vascular cell proliferation and prevented myoblast, endothelial and smooth muscle cell apoptosis in vitro. Our study suggests that although hAC133+ cell and hMAPC transplantation bothcontribute to vascular regeneration in ischemic limbs, hMAPC exert a more robust effect through trophic mechanisms, which translated into collateral and muscle fiber regeneration. This, in turn, conferred tissue protection and regeneration with longer-term functional improvement

A novel [89Zr]-anti-PD-1-PET-CT to assess response to PD-1/PD-L1 blockade in lung cancer

Background: Harnessing the anti-tumor immune system response by targeting the program cell death protein (PD-1) and program cell death ligand protein (PD-L1) axis has been a major breakthrough in non-small cell lung cancer (NSCLC) therapy. Nonetheless, conventional imaging tools cannot accurately assess response in immunotherapy-treated patients. Using a lung cancer syngeneic mouse model responder to immunotherapy, we aimed to demonstrate that [89Zr]-anti-PD-1 immuno-PET is a safe and feasible imaging modality to assess the response to PD-1/PD-L1 blockade in NSCLC. Materials and methods: A syngeneic mouse model responder to anti-PD-1 therapy was used. Tumor growth and response to PD-1 blockade were monitored by conventional 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) PET scans. Additionally, tumor lymphocyte infiltration was analyzed by the use of an [89Zr]-labeled anti-PD-1 antibody and measured as 89Zr tumor uptake. Results: Conventional [18F]-FDG-PET scans failed to detect the antitumor activity exerted by anti-PD-1 therapy. However, [89Zr]-anti-PD-1 uptake was substantially higher in mice that responded to PD-1 blockade. The analysis of tumor-infiltrating immune cell populations and interleukins demonstrated an increased anti-tumor effect elicited by activation of effector immune cells in PD-1-responder mice. Interestingly, a positive correlation between [89Zr]-anti-PD-1 uptake and the proportion of tumor-infiltrating lymphocytes (TILs) was found (Cor = 0.8; p = 0.001). Conclusion: Our data may support the clinical implementation of immuno-PET as a promising novel imaging tool to predict and assess the response of PD-1/PD-L1 inhibitors in patients with NSCLC

A novel [89Zr]-anti-PD-1-PET-CT to assess response to PD-1/PD-L1 blockade in lung cancer

Background: Harnessing the anti-tumor immune system response by targeting the program cell death protein (PD-1) and program cell death ligand protein (PD-L1) axis has been a major breakthrough in non-small cell lung cancer (NSCLC) therapy. Nonetheless, conventional imaging tools cannot accurately assess response in immunotherapy-treated patients. Using a lung cancer syngeneic mouse model responder to immunotherapy, we aimed to demonstrate that [89Zr]-anti-PD-1 immuno-PET is a safe and feasible imaging modality to assess the response to PD-1/PD-L1 blockade in NSCLC. Materials and methods: A syngeneic mouse model responder to anti-PD-1 therapy was used. Tumor growth and response to PD-1 blockade were monitored by conventional 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) PET scans. Additionally, tumor lymphocyte infiltration was analyzed by the use of an [89Zr]-labeled anti-PD-1 antibody and measured as 89Zr tumor uptake. Results: Conventional [18F]-FDG-PET scans failed to detect the antitumor activity exerted by anti-PD-1 therapy. However, [89Zr]-anti-PD-1 uptake was substantially higher in mice that responded to PD-1 blockade. The analysis of tumor-infiltrating immune cell populations and interleukins demonstrated an increased anti-tumor effect elicited by activation of effector immune cells in PD-1-responder mice. Interestingly, a positive correlation between [89Zr]-anti-PD-1 uptake and the proportion of tumor-infiltrating lymphocytes (TILs) was found (Cor = 0.8; p = 0.001). Conclusion: Our data may support the clinical implementation of immuno-PET as a promising novel imaging tool to predict and assess the response of PD-1/PD-L1 inhibitors in patients with NSCLC