Synthesis, Characterization, and Potential Usefulness in Liver Function Assessment of Novel Bile Acid Derivatives with Near-Infrared Fluorescence (NIRBAD)

• Published in: Bioconjugate chemistry Vol. 35; no. 7; pp. 971 - 980
• Main Authors: Temprano, Alvaro G., Sanchez de Blas, Beatriz, Pérez-Melero, Concepción, Espinosa-Escudero, Ricardo, Briz, Oscar, Cinca-Fernando, Paula, Llera, Lucia, Monte, Maria J., Bermejo-Gonzalez, Francisco A., Marin, Jose J.G., Romero, Marta R.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 17-07-2024
• Subjects: Acids; Animals; Bile Acids and Salts - chemistry; Biomarkers; CHO Cells; Cholestasis; Cholic acid; Cricetulus; Cycloaddition; Flow cytometry; Fluorescence; Fluorescent Dyes - chemistry; Fluorescent indicators; Fluorimetry; Fluorophores; I.R. radiation; Image resolution; Intestine; Ionization; Liver; Liver - diagnostic imaging; Liver - metabolism; Liver diseases; Liver Function Tests - methods; Male; Monitoring methods; Near infrared radiation; NMR; Nuclear magnetic resonance; Probes; Quadrupoles; Rats; Rats, Sprague-Dawley; Real time; Renal function; Spectroscopy, Near-Infrared - methods; Taurocholic acid; Toxicity
• ISSN: 1043-1802; 1520-4812; 1520-4812
• DOI: 10.1021/acs.bioconjchem.4c00168

Conventional serum markers often fail to accurately detect cholestasis accompanying many liver diseases. Although elevation in serum bile acid (BA) levels sensitively reflects impaired hepatobiliary function, other factors altering BA pool size and enterohepatic circulation can affect these levels. To develop fluorescent probes for extracorporeal noninvasive hepatobiliary function assessment by real-time monitoring methods, 1,3-dipolar cycloaddition reactions were used to conjugate near-infrared (NIR) fluorochromes with azide-functionalized BA derivatives (BAD). The resulting compounds (NIRBADs) were chromatographically (FC and PTLC) purified (>95%) and characterized by fluorimetry, 1H NMR, and HRMS using ESI ionization coupled to quadrupole TOF mass analysis. Transport studies using CHO cells stably expressing the BA carrier NTCP were performed by flow cytometry. Extracorporeal fluorescence was detected in anesthetized rats by high-resolution imaging analysis. Three NIRBADs were synthesized by conjugating alkynocyanine 718 with cholic acid (CA) at the COOH group via an ester (NIRBAD-1) or amide (NIRBAD-3) spacer, or at the 3α-position by a triazole link (NIRBAD-2). NIRBADs were efficiently taken up by cells expressing NTCP, which was inhibited by taurocholic acid (TCA). Following i.v. administration of NIRBAD-3 to rats, liver uptake and consequent release of NIR fluorescence could be extracorporeally monitored. This transient organ-specific handling contrasted with the absence of release to the intestine of alkynocyanine 718 and the lack of hepatotropism observed with other probes, such as indocyanine green. NIRBAD-3 administration did not alter serum biomarkers of hepatic and renal toxicity. NIRBADs can serve as probes to evaluate hepatobiliary function by noninvasive extracorporeal methods.