Liquid Biopsy for Patient Characterization in Cardiovascular Disease: Verification against Markers of Cytochrome P450 and P‐Glycoprotein Activities

Abstract

Precision dosing strategies require accounting for between-patient variability in pharmacokinetics together with subsequent pharmacodynamic differences. Liquid biopsy is a valuable new approach to diagnose disease prior to the appearance of clinical signs and symptoms, potentially circumventing invasive tissue biopsies. However, the possibility of quantitative grading of biomarkers, as opposed to simply confirming their presence or absence, is relatively new. In this study, we aimed to verify expression measurements of cytochrome P450 (CYP) enzymes and the transporter P-glycoprotein (P-gp) in liquid biopsy against genotype and activity phenotype (assessed by the Geneva cocktail approach) in 30 acutely ill patients with cardiovascular disease in a hospital setting. After accounting for exosomal shedding, expression in liquid biopsy correlated with activity phenotype for CYP1A2, CYP2B6, CYP2C9, CYP3A, and P-gp (r = 0.44-0.70, P ≤ 0.05). Although genotype offered a degree of stratification, large variability (coefficient of variation (CV)) in activity (up to 157%) and expression in liquid biopsy (up to 117%) was observed within each genotype, indicating a mismatch between genotype and phenotype. Further, exosome screening revealed expression of 497 targets relevant to drug metabolism and disposition (159 enzymes and 336 transporters), as well as 20 molecular drug targets. Although there were no functional data available to correlate against these large-scale measurements, assessment of disease perturbation from healthy baseline was possible. Verification of liquid biopsy against activity phenotype is important to further individualize modeling approaches that aspire to achieve precision dosing from the start of drug treatment without the need for multiple rounds of dose optimization.

Liquid Biopsies or Therapeutic Drug Monitoring for CYP Activity Profile Determination

“…This indicates a disconnect between hepatic protein expression and enzyme activity and a similar disconnect between plasma exosome cfRNA and hepatic enzyme activity would be anticipated. The authors also recently presented a relationship ( R = 0.44–0.7; P < 0.05; n = 30) among plasma exosomal cfRNA levels of CYP1A2, CYP2B6, CYP2C9, and CYP3A and activities monitored using the Geneva cocktail 2 . The data are interesting and should be verified in a larger cohort, however, the results presented here do not support such a relationship.…”

“…used liquid biopsies and found a correlation between plasma exosomal cfRNA expression and hepatic protein expression of 8 CYPs and 4 UGTs in 29 patients ( r = 0.6–0.89). In another relatively small study ( n = 30) a correlation ( r = 0.44–0.70; P < 0.05) between cfRNA and activity of four different CYPs in patients was phenotyped using the Geneva cocktail 2 …”

The impact of CYP2D6*41 on CYP2D6 enzyme activity using phenotyping methods in urine, plasma, and saliva

“…Recent study suggests liquid biopsy provides a practical way to quantify cytochrome P450 expression level which correlates well to metabolic activity. This promising technique may contribute to precision dosing therapy (Achour et al, 2022). Frontiers in Pharmacology frontiersin.org…”

Clinical Implications of Altered Drug Transporter Abundance/Function and PBPK Modeling in Specific Populations: An ITC Perspective

“…In addition to the standardization of tissue sample collection, LC‐MS/MS quantification methods, understanding of the relationship between protein expression, and function of clinically important transporters in healthy subjects, diseased, and specific populations will ultimately improve the translation of transporter proteomic data in PBPK models. (ii) Recently, tissue‐derived plasma small extracellular vesicles (sEVs), such as exosomes, have emerged as a novel and promising tool in determining the metabolic enzyme and transporter profile in human tissues 103–106 . The exosomes isolated from human plasma (“liquid biopsy”) can provide a rich and informative dataset on protein expression of transporters in various tissues of healthy subjects, and diseased and specific populations, where the access of tissue samples is not feasible and/or limited.…”

“…(ii) Recently, tissuederived plasma small extracellular vesicles (sEVs), such as exosomes, have emerged as a novel and promising tool in determining the metabolic enzyme and transporter profile in human tissues. [103][104][105][106] The exosomes isolated from human plasma ("liquid biopsy") can provide a rich and informative dataset on protein expression of transporters in various tissues of subjects, and diseased and specific populations, where the access of tissue samples is not feasible and/or limited. So far, a good was demonstrated between mRNA in isolated human plasma exosomes and protein expression in liver tissues for 12 key transporters (OATP1B1, P-gp, BCRP, and MRP2) in patients with liver cancer, in addition to some PD targets.…”