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In vivo alteration of RES phagocytosis by magnetic albumin microspheres
Abstract:
The effect of non-localized magnetically responsive albumin microspheres (MR-AMS) on RES phagocytic function was investigated. MR-AMS and MR-AMS containing Adriamycin (MR-AMS-ADR) were injected intravenously in rats at a dose which saturated all RES phagocytes. The ability of the RES to clear the bloodstream of a subsequent suspension of MR-AMS or streptococci was then analyzed over a three day period. MR-AMS clearance was enhanced after initial RES saturation with MR-AMS but depressed when the saturating agent was MR-AMS-ADR. Bloodstream clearance of streptococci was depressed by MR-AMS and MR-AMS-ADR. Localization of MR-AMS in the RES might depress RES phagocytosis by physical saturation of phagocytes or by a direct toxic effect of encapsulated chemotherapeutic agents.
Insights
Magnetically responsive albumin microspheres (MR-AMS) impact RES phagocytic function. While MR-AMS alone enhanced clearance, Adriamycin-loaded MR-AMS depressed streptococcal clearance, suggesting saturation or toxicity effects.
Area of Science:
- Pharmacology
- Immunology
- Biomaterials
Background:
- The reticuloendothelial system (RES) plays a crucial role in clearing foreign particles and pathogens from the bloodstream.
- Magnetically responsive albumin microspheres (MR-AMS) are being explored for targeted drug delivery, but their impact on immune function requires investigation.
Purpose of the Study:
- To investigate the effect of non-localized MR-AMS and Adriamycin-loaded MR-AMS (MR-AMS-ADR) on RES phagocytic function in vivo.
- To determine how RES phagocyte saturation with MR-AMS influences the clearance of subsequent MR-AMS or streptococci.
Main Methods:
- Intravenous injection of MR-AMS and MR-AMS-ADR into rats to saturate RES phagocytes.
- Analysis of the RES's ability to clear a subsequent suspension of MR-AMS or streptococci over a three-day period.
Main Results:
- RES phagocytic clearance of subsequent MR-AMS was enhanced after initial saturation with MR-AMS.
- However, RES clearance of streptococci was depressed by both MR-AMS and MR-AMS-ADR.
- MR-AMS-ADR significantly depressed the clearance of subsequent MR-AMS compared to MR-AMS alone.
Conclusions:
- RES phagocytosis can be modulated by the presence of MR-AMS.
- The encapsulation of Adriamycin within MR-AMS may lead to a direct toxic effect on phagocytes, impairing their function.
- Potential mechanisms for depressed phagocytosis include physical saturation of phagocytes or direct toxicity from chemotherapeutic agents.