BackgroundMolecular components in blood, such as proteins, are used as biomarkers to detect or predict disease states, guide clinical interventions and aid in the development of therapies. While... Show moreBackgroundMolecular components in blood, such as proteins, are used as biomarkers to detect or predict disease states, guide clinical interventions and aid in the development of therapies. While multiplexing proteomics methods promote discovery of such biomarkers, their translation to clinical use is difficult due to the lack of substantial evidence regarding their reliability as quantifiable indicators of disease state or outcome. To overcome this challenge, a novel orthogonal strategy was developed and used to assess the reliability of biomarkers and analytically corroborate already identified serum biomarkers for Duchenne muscular dystrophy (DMD). DMD is a monogenic incurable disease characterized by progressive muscle damage that currently lacks reliable and specific disease monitoring tools.MethodsTwo technological platforms are used to detect and quantify the biomarkers in 72 longitudinally collected serum samples from DMD patients at 3 to 5 timepoints. Quantification of the biomarkers is achieved by detection of the same biomarker fragment either through interaction with validated antibodies in immuno-assays or through quantification of peptides by Parallel Reaction Monitoring Mass Spectrometry assay (PRM-MS).ResultsFive, out of ten biomarkers previously identified by affinity-based proteomics methods, were confirmed to be associated with DMD using the mass spectrometry-based method. Two biomarkers, carbonic anhydrase III and lactate dehydrogenase B, were quantified with two independent methods, sandwich immunoassays and PRM-MS, with Pearson correlations of 0.92 and 0.946 respectively. The median concentrations of CA3 and LDHB in DMD patients was elevated in comparison to those in healthy individuals by 35- and 3-fold, respectively. Levels of CA3 vary between 10.26 and 0.36 ng/ml in DMD patients whereas those of LDHB vary between 15.1 and 0.8 ng/ml.ConclusionsThese results demonstrate that orthogonal assays can be used to assess the analytical reliability of biomarker quantification assays, providing a means to facilitate the translation of biomarkers to clinical practice. This strategy also warrants the development of the most relevant biomarkers, markers that can be reliably quantified with different proteomics methods. Show less
Bruggen, W. van der; Hagelstein-Rotman, M.; Geus-Oei, L.F. de; Smit, F.; Dijkstra, P.D.S.; Appelman-Dijkstra, N.M.; Vriens, D. 2020
Purpose To quantify (NaF)-F-18-PET/CT uptake in relation to clinical and biochemical parameters of fibrous dysplasia (FD) severity and healthy bone (HB) metabolism. Secondary aims: comparing... Show morePurpose To quantify (NaF)-F-18-PET/CT uptake in relation to clinical and biochemical parameters of fibrous dysplasia (FD) severity and healthy bone (HB) metabolism. Secondary aims: comparing normalization for volume of distribution and determining reproducibility of (NaF)-F-18-PET/CT uptake parameters in HB and FD. Relating (NaF)-F-18 uptake to skeletal burden score (SBS), bisphosphonate therapy and pain measured by Brief Pain Inventory (BPI). Methods In a prospective cohort study (n = 20), (NaF)-F-18-PET/CT parameters of HB and FD were assessed by two independent readers to determine the cutoff defining increased bone uptake, optimized normalization, and interobserver agreement (ICC) and were related to SBS, serum biomarkers, medication, and clinical parameters. Results Physiological bone standardized uptake value (SUV) was best normalized but displayed large interpatient variation (total range 4.1-13.7 g/mL), with very high interobserver agreement (ICC = 0.964). FD burden defined by patient-specific SUV cutoffs reached near-perfect agreement for SUVpeak (ICC = 0.994) and total lesion fluorination (TLF) (ICC = 0.999). TLF correlated weakly with SBS (R-2 = 0.384, p = 0.047). TLF correlated positively with serum alkaline phosphatase (R-2 = 0.571, p = 0.004) and procollagen type 1 N-terminal propeptide (R-2 = 0.621, p = 0.002), SBS did not (p > 0.06). SBS and TLF both correlated with increased fibroblast growth factor-23 (R-2 = 0.596, p = 0.007 and R-2 = 0.541, p = 0.015, respectively). TLF was higher in use of bisphosphonates (p = 0.023), SBS was not. Average BPI scores correlated to increased FGF-23 (R-2 = 0.535, p = 0.045), work-related BPI scores to higher SBS (R-2 = 0.518, p = 0.024), higher TLF (R-2 = 0.478, p = 0.036), and higher levels of FGF-23 (R-2 = 0.567, p = 0.034). Conclusions Individualized (NaF)-F-18-PET/CT SUV cutoffs reproducibly discriminated HB from FD and were well-normalized. The strong relations of bone formation serum markers with (NaF)-F-18-PET/CT FD burden measurements suggest clinical relevance over SBS as an adjunct instrument in FD patients. The correlation of both imaging modalities with increased work-related BPI scores also indicates clinical applicability. Moreover, SBS is known to remain stationary irrespective of use of medication, whereas TLF on (NaF)-F-18-PET/CT was higher in baseline patients using bisphosphonates. This makes (NaF)-F-18-PET/CT a promising tool to quantitatively measure treatment efficacy in FD. Show less
Signorelli, M.; Ayoglu, B.; Johansson, C.; Lochmuller, H.; Straub, V.; Muntoni, F.; ... ; Spitali, P. 2019
