Divalent trace metals (TM), especially copper (Cu), cobalt (Co) and zinc (Zn), are recognized as essential microelements for tissue homeostasis and regeneration. To achieve a balance between therapeutic activity and safety of administered TMs, effective gel formulations of TMs with elucidated regenerative mechanisms are required. We studied in vitro and in vivo effects of biodegradable macroporous cryogels doped with Cu, Co or Zn in a controllable manner. The extracellular ROS generation by metal dopants was assessed and compared with the intracellular effect of soluble TMs. The stimulating ability of TMs in the cryogels for cell proliferation, differentiation and cytokine/growth factor biosynthesis was characterized using HSF and HUVEC primary human cells. Multiple responses of host tissues to the TM-doped cryogels upon subcutaneous implantation were characterized taking into account the rate of biodegradation, production of HIF-1α/matrix metalloproteinases and the appearance of immune cells. Cu and Zn dopants did not disturb the intact skin organization while inducing specific stimulating effects on different skin structures, including vasculature, whereas Co dopant caused a significant reorganization of skin layers, the appearance of multinucleated giant cells, along with intense angiogenesis in the dermis. The results specify and compare the prooxidant and regenerative potential of Cu, Co and Zn-doped biodegradable cryogels and are of particular interest for the development of advanced bioinductive hydrogel materials for controlling angiogenesis and soft tissue growth.
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Acknowledgments: This work was co-funded by the Russian Science Foundation (research project 20-73-10105 in studying ROS-generating activity of TM formulations) and is part of Kazan Federal University (KFU) Strategic Academic Leadership Program. Ilnur Salafutdinov (Institute of Fundamental Medicine and Biology, KFU) is greatly acknowledged for invaluable assistance. The authors thank S.V. Fedosimova and A.G. Daminova (Interdisciplinary Center for Analytical Microscopy, KFU) for LSCM analysis and I.T. Rakipov (Alexander Butlerov Institute of Chemistry, KFU) for rheological analysis.
Funding: The reported study was funded by RFBR and VAST according to the research project 21-515-54003.
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- wound healing
- Transition metals