Of Isotopes and 'Omics

Our NMR-Based Metabolomics Facility Helps Science Sleuths ‘Dust’ for Chemical Fingerprints 

Meet “Leonard.” That’s the nickname for our fully automated Bruker IVDr 600MHz nuclear magnetic resonance (NMR) spectroscopy platform. In 2015, Cincinnati Children’s became the first hospital in the region to install this latest iteration of high-throughput NMR screening technology. “Leonard” is packed with auto-samplers, screening software and other tech needed to produce extremely detailed portraits of the chemical activity happening within a biological sample. The tool is helping scientists here advance the emerging field of metabolomics, which tracks metabolite levels in cells, organs, tissues or organisms. Observed together, these measurements offer a detailed portrait of a person’s underlying molecular network and could soon become a precious tool in treating and preventing illness. “The idea of studying metabolism by use of NMR has been around for almost 50 years,” says Lindsey Romick-Rosendale, PhD, Director of the NMR-Based Metabolomics Core since its founding in March 2014. “It has improved recently because only within the last 10 years have our databases of reference spectra become sophisticated enough to really identify significant numbers of metabolites.” 

Beyond a snapshot

For example, stable isotope labeling experiments have emerged as a new method for understanding the broad implications of metabolites. Previously, analyzing a blood, urine or fecal sample might provide a snapshot of a patient’s metabolic state. Such snapshots can depict impressive collections of amino acids, antibiotics, pigments, carbohydrates and fatty acids. But that data would not show what complex compounds were converted to make those metabolites, nor where they originated.

Here, investigators run isotope tracer experiments that go beyond static snapshots. NMR can follow stable isotopes as they travel within cells in a dish, within mouse models, even in a cancer patient just before a tumor resection. By following how metabolites break down and flux along multiple pathways, investigators can learn how nutrients are used by healthy cells compared to unhealthy ones. “You can see what gets ramped up, what pathways get turned off,” says Romick-Rosendale. “Eventually, this information could lead to tests to diagnose health risks. Or it could translate in other ways, such as developing ways to supplement patients with certain metabolic deficiencies.”

NMR is a non-destructive technology, so if a researcher or clinician only has a few samples from a rare disease population or samples that cannot be acquired again, the facility can run the sample and then return it. The NMR team also tailors study designs, experiments and sample collections to individual studies and investigators.

Multitude of applications

Among the many ways the NMR-based Metabolomics Core supports scientific exploration:

  • Analyzing pregnant women’s urine in longitudinal studies—when no other medical risk factors are present—to identify metabolic biomarkers related to spontaneous preterm delivery.
  • A study in the Journal of Experimental Biology published by Andrew Rosendale, a fellow at the University of Cincinnati, investigating how ticks survive dehydration while awaiting hosts. New understanding could lead to ways to prevent tick-borne diseases.
  • Helping animals at the Cincinnati Zoo. In a recent study, published in PLOS ONE, the NMR facility helped analyze an iron-loading disorder in rhinoceroses. The team also works with the zoo to hunt for renal cancer biomarkers in fishing cats and identify pseudo-pregnancies in polar bears.

The facility also offers another useful advantage. “NMR studies are unbelievably reproducible,” Romick-Rosendale says. Some technologies are more sensitive than NMR for identifying metabolites. However, those approaches often come with problems, such as batch-to-batch variability in samples. When data consistency matters, the reliability of NMR makes it useful for verifying results obtained from other technologies, especially for longitudinal studies.