Mass spectrometric study of variation in kinin peptide profiles in nasal fluids and plasma of adult healthy individuals

Abstract

Background The kallikrein-kinin system is assumed to have a multifunctional role in health and disease, but its in vivo role in humans currently remains unclear owing to the divergence of plasma kinin level data published ranging from the low picomolar to high nanomolar range, even in healthy volunteers. Moreover, existing data are often restricted on reporting levels of single kinins, thus neglecting the distinct effects of active kinins on bradykinin (BK) receptors considering diverse metabolic pathways. A well-characterized and comprehensively evaluated healthy cohort is imperative for a better understanding of the biological variability of kinin profiles to enable reliable differentiation concerning disease-specific kinin profiles. Methods To study biological levels and variability of kinin profiles comprehensively, 28 healthy adult volunteers were enrolled. Nasal lavage fluid and plasma were sampled in customized protease inhibitor prespiked tubes using standardized protocols, proven to limit inter-day and interindividual variability significantly. Nine kinins were quantitatively assessed using validated LC–MS/MS platforms: kallidin (KD), Hyp4-KD, KD1-9, BK, Hyp3-BK, BK1-8, BK1-7, BK1-5, and BK2-9. Kinin concentrations in nasal epithelial lining fluid were estimated by correlation using urea. Results Circulating plasma kinin levels were confirmed in the very low picomolar range with levels below 4.2 pM for BK and even lower levels for the other kinins. Endogenous kinin levels in nasal epithelial lining fluids were substantially higher, including median levels of 80.0 pM for KD and 139.1 pM for BK. Hydroxylated BK levels were higher than mean BK concentrations (Hyp3-BK/BK = 1.6), but hydroxylated KD levels were substantially lower than KD (Hyp4-KD/KD = 0.37). No gender-specific differences on endogenous kinin levels were found. Conclusions This well-characterized healthy cohort enables investigation of the potential of kinins as biomarkers and would provide a valid control group to study alterations of kinin profiles in diseases, such as angioedema, sepsis, stroke, Alzheimer’s disease, and COVID-19.

Multiplex Hybrid Antigen-Capture LC-MRM Quantification in Sera and Nasal Lining Fluid of AZD7442, a SARS-CoV-2-Targeting Antibody Combination

“…Gangnus et al (2022) recently reported NLF kinin peptide quantification using a fully validated LC-MS/MS method employing solid-phase extraction with urea normalization. 43 The assay achieved high sensitivity with reported LLOQ for kinin peptide quantification in NLF of 1.9 pmol/L. Therefore, the approach reported herein is the first description of quantitative biotherapeutic bioanalysis in NLF using a hybrid LBA-LC-MS/MS method with concentration normalization via urea correlation (described elsewhere).…”

“…To our knowledge, only one LC-MS/MS method related to protein profiling in NLF has been reported in peer-reviewed publications to date. Gangnus et al (2022) recently reported NLF kinin peptide quantification using a fully validated LC-MS/MS method employing solid-phase extraction with urea normalization . The assay achieved high sensitivity with reported LLOQ for kinin peptide quantification in NLF of 1.9 pmol/L.…”