Metabolism in Motion
Stable isotope tracing: what it measures, when to use it, and where it goes wrong
Metabolite concentrations tell you what is there. They do not tell you what is happening.
A pathway can look completely normal at the level of abundance, while the flow through it has doubled or stopped. Stable isotope tracing is the method that makes that flow visible; you administer a safe, non-radioactive labeled nutrient, follow the label through the metabolic network, and read out activity rather than a snapshot.
If you are considering a tracing experiment and want to understand the method before committing to it, what it measures, what it cannot measure, what it costs in design effort, and where it can go wrong, this is the right seminar for you. If you do not know what tracing is, but metabolism helps your research, this is the right seminar for you as well.
Plenty of time for discussion and working through real cases — no laptops, no software. Bring a research question and a curious mind.
After this afternoon, you will be able to
- Explain what a tracer experiment actually measures, and why labeling is not the same as flux
- Judge whether your own question needs tracing, or whether metabolite abundance already answers it
- Recognize the design decisions that determine whether an experiment works: tracer choice, route, timing, sampling, controls
- Anticipate the practical limits of tracing in vivo and in a clinical setting
Who it is for
PhD students, postdocs, and group leaders in basic and clinical research where metabolism matters; oncology, inherited metabolic disease, immunology, endocrinology, nutrition, cardiovascular, and neurometabolic research. No prior experience with isotope tracing is assumed. Clinicians with a research question and no MS background are explicitly welcome.
Programme
Session 1 — Foundations (13:00–14:30)
- Welcome, and why Zurich Trace exists — Prof. Ralph Schlapbach (FGCZ) and Dr. Alaa Othman (FGCZ), with Dr. Raphael J. Morscher (University Children's Hospital Zurich) and Prof. Dr. Thorsten Hornemann (University Hospital Zurich)
- What is tracing, and why? — fundamentals, underlying principles, and why tracing is not flux . Prof. Dr. Nicola Zamboni, ETH Zurich, develops the methods and software behind quantitative flux analysis
- In vivo tracing — design and interpretation in animal models and in humans Dr. Dr. Raphael J. Morscher, University Children's Hospital Zurich, uses in vivo stable isotope tracing to map patient-specific metabolic networks in childhood cancer; recent work in Nature traced the circulating sources of tumor polyamine precursors and reprogrammed neuroblastoma through diet-enhanced polyamine depletion
- Open discussion with both speakers
Coffee break and meet-the-expert tables (14:30–15:00) : Six themed tables staffed by the Zurich Trace PIs. Come with a question.
Session 2 — Applications, and putting it to work (15:00–16:30)
- Tracing (sphingo)lipids in humans and models Prof. Dr. Thorsten Hornemann, University Hospital Zurich, traced a class of neurotoxic sphingolipids from a rare inherited neuropathy through to type 2 diabetes: mechanism, biomarker, and a route to lowering them
- Tracing in inherited metabolic disorders, Prof. Dr. Sean Froese, University Children's Hospital Zurich — works on tracing revealed anaplerotic rewiring in methylmalonic aciduria and a candidate intervention
- A case from the research platform — Dr. Alaa Othman, FGCZ
- "Would tracing answer my question?" — guided small-group session on real cases, with all speakers
Apéro (from 16:30) — expert tables continue.
Preliminary program; timings for individual talks may still shift slightly
About Zurich Trace
Zurich Trace is a University Medicine Zurich (UMZH) Clinical platform that develops advanced stable-isotope tracing services for clinical use and bedside clinical research. It brings together the University Hospital Zurich (USZ), the University Children's Hospital Zurich (Kispi), UZH, ETH Zurich, and the Functional Genomics Center Zurich (FGCZ) to enable functional metabolic diagnostics that go beyond static snapshots. → zurichtrace.ch
