Longitudinal microsampling within the overall trends towards telehealth and precision medicine
Blood microsampling, which enables patients to provide longitudinal samples without attending a hospital or pathology lab, is developing rapidly and is an important component that links the other two major trends, telehealth and precision medicine. Incorporating a longitudinal dimension to sample collection and analysis enables a big data approach to patient stratification.
The recalibration of the healthcare system is discussed in publications such as this recent one from the New England Journal of Medicine; ‘The Transition from Reimagining to Recreating Health Care Is Now’. The authors discuss the perceived impediments that led to slow adoption of telemedicine, the changes that came with the Covid-19 pandemic, and advice on how to most easily implement a telemedicine program rapidly. In this context, telemedicine in conjunction with point-of-care testing and remote microsampling will become increasingly important; facilitating patient engagement and therapy while reducing viral transmission risk.
Sangui Bio uses Neoteryx Mitra devices for micro-sampling and has developed proprietary methods to maximise biomarker identification from dried blood samples by enabling sequential extraction. The sequential extractions are suitable for both immuno-assays and mass spectrometry. This approach facilitates analysis of blood proteome fractions that are not commonly examined, such as intra-cellular proteins including CD-markers and cytokines that may be present in the cellular fractions, including red blood cells.
Conventional plasma proteomics is slow and expensive.
Unique processing and analytical methods
Our methods are simple and can quickly produce large numbers of protein identifications out of complex samples such as whole blood. These methods can also be applied to other cellular fractions such as PBMCs or plasma.
Case study: NSCLC (non-small cell lung carcinoma)
Plasma and corresponding frozen whole blood cell pellet samples were collected from 16 NSCLC donors (cancer staging ranging from II to IV) and 18 age and sex matched controls. Cell pellet samples (30 µL) were collected into Mitra microsampling devices and were processed through the Sangui Bio proprietary sequential extraction protocol. Prior to analysis, samples had been frozen and in storage for up to 7 years.
Despite this, mass spectrometry data was highly reproducible between replicates and resulted in high protein yield across the whole cohort (Figure 1). Approximately 3500 protein IDs were detected per sample.
Figure 1. Protein ID yield from samples collected from healthy controls (n=18) and NSCLC patients (n=16). Each grey and black pair represents a pair of technical replicates from a single participant.
This analysis revealed over 500 differentially expressed proteins and identified a specific subset of cancer patients that share a unique biomarker profile.
Molloy, M. P., Hill, C., O'Rourke, M. B., Chandra, J., Steffen, P., McKay, J., Pascovici, D., Herbert, B. R. Proteomic analysis of whole blood using volumentric absorptive microsampling for precision medicine biomarker studies. Journal of Proteome Research. (2022).