Fluorescent probing of the ligand-binding ability of blood plasma in the acute-phase response

Area of Science:

• Biochemistry
• Clinical Chemistry
• Pharmacology

Background:

• The acute-phase response modifies plasma carrier proteins, potentially altering drug and biomediator transport.
• Understanding these changes is crucial for optimizing drug efficacy and safety, especially in vulnerable patient populations.

Purpose of the Study:

• To investigate the impact of the acute-phase response on plasma ligand-binding properties in leukemic children.
• To assess how systemic inflammation (sepsis and septic shock) affects the binding of fluorescent probes to plasma transport proteins.

Main Methods:

• Utilized differentially charged fluorescent dyes (anionic ANS, uncharged Nile red, cationic Quinaldine red) to probe different transport proteins.
• Analyzed synchro-scan fluorescence spectra to determine dye distribution among plasma proteins like albumin, lipoproteins, and alpha(1)-acid glycoprotein.
• Compared probe binding in leukemic children with and without systemic inflammation against a control group.

Main Results:

• Leukemia increased Quinaldine red binding by 65% but did not significantly alter ANS or Nile red binding.
• Sepsis and septic shock decreased ANS binding by approximately 33% and shifted Nile red binding from albumin to lipoproteins.
• Quinaldine red binding correlated with alpha(1)-acid glycoprotein, independent of albumin and lipoprotein levels.

Conclusions:

• The acute-phase response significantly modifies the composition and ligand-binding characteristics of key plasma transport proteins.
• Developed fluorescent tests can effectively evaluate the acute-phase response and aid in optimizing drug administration protocols.
• Findings highlight the need to consider altered protein binding in therapeutic strategies for critically ill pediatric patients.