In a recent study published in Nature Biomedical Engineeringresearchers developed a multi-omic-based microsampling workflow for profiling proteins, metabolites, lipids, and cytokines and specific hormones, i.e., multiple analytes, in a single 10 μl blood sample (microsample).
The researchers tried to show how well the microsampling method can capture natural changes related to human life.
History
Despite advances in multi-omics technologies, current sample collection and processing methods are challenging. They require a visit to the hospital and access to a phlebotomist and are not fully adjustable and non-invasive, which makes the patient feel uncomfortable.
In addition, they need 10 to 50 ml of venous blood, reducing the frequency of collection, which prevents a great analysis of the biological processes that occur inside the body for minutes or hours. Finally, high sampling rates may be a factor in dissuading people from participating in larger studies in remote areas.
Studies have shown that dried blood spot (DBS) samples are often inconsistent, which hinders analyte analysis due to lack of sample size.
However, volumetric absorptive microsampling (VAMS) is highly sensitive and achieves good performance for target metabolites, such as lipids and proteins. Compared to DBS, VAMS is easier to use and easier to perform remotely for local preferences.
About this study
In the current study, researchers reported two cases that demonstrate the analytical potential of a multi-omics microsampling workflow in capturing and analyzing thousands of metabolites, lipids, cytokines, and proteins in 10 μl of blood. He used a solid matrix device, the Mitra, to collect stagnant blood.
Likewise, the group chose biphasic extraction with methyl tert-butyl ether (MTBE) to efficiently extract lipids, proteins, and metabolites from 10 μl blood (micro) samples. Moreover, it ensured that these analytes are in a well-organized array to obtain proteomics data. They used a small blood sample for multiplexed immunoassays.
Finally, the team analyzed this data that was organized, annotated, and stored. In addition, the researchers used wearable sensors in combination with multiple microsampling to support health profiles, for example, inter-day changes in heart rate (HR).
In the first empirical study, they tested the response to a complex food method, i.e., Check shake, to find inflammatory and metabolic responses at the human level. They analyzed 28 people with different backgrounds to create six response metrics.
The second observational study helped the researchers to identify significant molecular changes and several molecular associations related to changes in the body and physical activity during the day, and clinical biomarker levels, such as glucose and cortisol. He did this with certainty or very dense ’24 by 7′ using 98 small samples per week. All participants had small blood samples taken one to two hours after waking for seven days, with some samples as short as 30 minutes apart. It enabled researchers to collect 98 microsamples with wearable data from two devices, a smartwatch and a continuous glucose monitor (CGM).
Study your findings
In response to the introduction of a mixed food shake, with complex problems, the researchers noticed that there is a big difference in the individual responses and the immune system. The researchers found 155 lipids, 560 metabolites, and 54 cytokines/hormones in each subsample. Most metabolites and lipids concentrations reached their highest levels after approximately ~60 and 120 minutes of drinking shakes, respectively, and returned to baseline levels by 240 minutes. Future research should reveal the reasons for these individual differences to help improve diet and lifestyle changes to have good health, weight loss, and metabolic disease control.
However, the proposed method can be useful in research and large-scale stability studies, because the parameters remain stable over time and with different temperatures before they are achieved. Most analytes, especially proteins, remained stable, while lipids were unstable analytes. Other problems may arise with unstable molecules. To do this, first, sample collection methods can include fast and cold shipping because processing them within 24 hours can reduce spoilage. Another way would be to count them from their damaged items.
In a second study, the researchers collected 214,661 biochemical measurements in addition to physical wear data to help analyze the entire human body and lifestyle, hourly changes, and individual relationships. They classified 2,213 internal molecules into 11 groups using fuzzy c-population analysis, of which two followed circular paths. Cluster 4 enriched in several metabolites increased significantly during the day, while cluster 11, which contains lipids, increased significantly during the night. The microsampling method also captured the pharmacokinetics of aspirin, a drug taken by study participants over four days. It identified its hydrolyzed product, salicylic acid, and revealed a shelf life of ~24 hours.
The end
Overall, the study method can reliably quantify thousands of molecules, including hormones and cytokines, even at low concentrations in blood.
The randomized multi-omics system of the present study enabled the slow extraction of molecules with a fixed volume of 10 μl. The finger prick blood collection method minimizes pain and allows us to take samples in minutes without going to the hospital or a lab technician. Also, it was scalable and easy to do remotely.
Overall, it demonstrated the potential for large-scale, scalable molecular and digital biomarker discovery, monitoring, and health profiling.
