Today I, Gunnar Cedersund, held the final keynote presentation at the Lund Engineering Health annual meeting. The audience featured engineers, medical doctors, physicists and other disciplines connected to biomedical engineering and health. The topic of this year’s conference was Sustainability, i.e. connections between health and the environment, climate, pollutants, social interactions, etc. It was fun to think about how our digital twins can contribute to those broader questions, and my presentation was followed by quite a lot of discussion and questions, which even continued on the train ride home afterwards. As usual, the core of the presentation was our 25 years of building up these twins, as well as ongoing implementations and trials we do in the M4-HEALTH and STRATIF-AI networks.
Thanks for inviting me, and for giving me the honor of giving the final keynote, ending the entire event!
The AI research of our esteemed ISB Group colleagues Rasmus Magnusson and Elin Nyman together with professor Henrik Green enables more precise estimation of the time of death. The research has been carried out in collaboration with the Swedish National Board of Forensic Medicine, and is a valuable advance in forensic investigations.
The method analyses metabolites, small molecules in the blood that change in predictable ways as the organs and tissue begin to break down after death. Using nearly 4,900 blood samples from autopsies, researchers trained an AI model to estimate the time between death and autopsy.
The model can predict the post-mortem interval with an accuracy of around one day, even when as many as 13 days have passed since death. This is a significant improvement over established methods such as body temperature, rigor mortis and potassium levels in the eye, which become less reliable several days after death. The researchers are now working to develop even more accurate models that could eventually determine not only the date, but also the approximate time of day when a person died—providing an important new tool for forensic investigations.
Understanding when—and how much—alcohol has been consumed is essential in both healthcare and forensic contexts. Yet this remains a surprisingly difficult task. Self-reported drinking data can be unreliable due to stigma, impaired memory, or legal consequences. Objective biomarkers such as blood- and breath alcohol concentrations (BAC and BrAC) are widely used, but they decline rapidly, making it difficult to reconstruct past drinking events with precision. At the same time, slower biomarkers like ethyl glucuronide (EtG), ethyl sulphate (EtS), and urine alcohol concentration (UAC) provide valuable complementary information, but existing approaches rarely combine these data sources in a meaningful, mechanistic way. In our newly accepted article, “A Digital Twin Framework for Forensic Reconstruction of Alcohol Intake via Fast and Slow Metabolite Kinetics,” we present a solution to this long-standing challenge.
We introduce a physiological digital twin that integrates the kinetics of both fast-acting and slow-acting alcohol biomarkers into a single mechanistic framework. This allows us to: • Capture the joint dynamics of BAC, BrAC, EtG, EtS, and UAC • Reconstruct past drinking events with improved temporal precision • Support forensic evaluations, including scenarios like refuting the hipflask defence • Enable personalized simulations of alcohol metabolism based on individual physiology By linking these biomarkers mechanistically rather than statistically, the model leverages the strengths of each marker, improving inference in situations where forensic accuracy is critical.
Improving Forensic Reconstruction
Our digital twin demonstrates clear benefits: • Higher reconstruction accuracy: Combining markers reduces ambiguity in the timing and quantity of consumed alcohol. • Robustness for complex scenarios: The model supports analyses requiring fine-grained temporal resolution—something single-marker models struggle with. • Practical usability: We provide an interactive web tool where users can explore hypothetical drinking scenarios and visualize expected biomarker trajectories. This tool is designed for forensic analysts, clinicians, toxicologists, and researchers interested in alcohol metabolism and its quantitative reconstruction.
Bridging Clinical, Forensic, and Computational Domains
We see this work as a foundation for precision modelling in alcohol kinetics. By moving toward unified digital twins grounded in physiology, we can support decision-making in healthcare and legal settings with more transparency, reproducibility, and individualized insight. We’re excited to share this contribution with the community and look forward to continued collaborations around modelling, biomarker research, and forensic applications.
If you’d like to try the interactive simulation tool, feel free to reach out!
There is a big demand to hear about our digital twins these days. Almost every week, we have been invited to give a lecture in some event, somewhere in the world. And some weeks more than one. In fact, last week, a new record was reached: 5 presentations in 25h! Here is a short description of the five presentations:
1 – Oct 14, 13.15-13.45: Joint presentation with Johan Holmsäter at Holistal’s event Health HUB. This was together with some of the most prominent health leaders in Sweden. Johan Holmsäter started the 500 000 people strong health organization Friskis & Svettis, and is arguably the single person that has made the biggest impact for the health and healthy habits in Sweden. Other important presenters were Birgitta Thörn (CEO of Holistal, and founder of e.g. the gym & health chain Itrim), Göran Adlén (the “aging backwards” guy, and a great lecturer), Anders Rosengren (a Swedish MD with lots of interesting ideas about the mentality of health, and the founder of the successful online tool Livsstilsverktyget), etc. You can read more about the event here, and at these two previous blog posts: post by me, post by Katja.
From the final panel debate. You see Johan Holmsäter to the right in an armchair, Göran Adlén to the left on stage, and Anders Rosengren to the right, also on stage.
2 – Oct 15, 10-12: General rehersal at Norlandia, in the DN house, for the big launch event of our digital twin app, to be held the week after. I had a presentation of ~25 min prepared, where I present how our multi-level and multi-organ digital twin for individuals will enter into an eHealth app, that will be given to all 3000 employees at Norlandia. More about the actual launch event (which was held on Oct 23), will come in a separate blog post.
3 – Oct 15, 12.50-13.20: Pod cast with Cambio, at the big Cambio Connect event. This podcast was broadcasted live for all attendees in the event, over lunch, and will also be sent out later in the autumn to around 1500 health care personnel.
Me, just before the podcast, with the preceding podcast behind me.
4 – Oct 15, 13.35-13.55 Presentation at the final workshop of MeDigit, a VINNOVA financed project on medical digital twins. I held this presentation online, from a corner in one of the corridors. The minute I was finished, some staff came up to me, and said that I had to “mic up” for the next presentation 🙂
5 – Oct 15, 14.20-14.35 Presentation and panel debate at the big stage at the Cambio Connect event. This was part of the last session, on AI, and wrapped up my crazy 25 hours of presentations, presentations, presentations! After this, it was time to relax a bit, and chill out a few hours at my hotel, before travelling home to Linköping again.
Picture of me at the dinner on Oct 14, in the evening. I didn’t have a lecture then, but this picture gives a feeling for the scale of the event, and the size of the big stage: it probably featured 500+ participants.
Next week, I will be in Stockholm to give presentations at some different events. First out is Health HUB, arranged by HOLISTAL, and focusing on preventive health. I am giving this presentation together with the health guru Johan Holmsäter, who – among many other things – founded Friskis & Svettis (half a million members!), back in the early 1980s. Since then, he has done many things, and one of them is corporate health. In this, he has many examples of turning around high rates of sick leave (e.g. 8% to 2%) by utilizing some of his various health programs. In the last 1-2 years, Johan, our spinoff company SUND, and a few others have jointly founded a new company – Lev Skönare – which now are rolling out a joint product: his health programs empowered by our digital twins. In this joint presentation, you will hear about both of our personal and professional journeys, as well as about the health journey “Hälsoresan”, which our customer Norlandia is about to embark upon next week.
Later in the week, on Wednesday, I will give a presentation at the event Cambio Connect. More info about that in a separate video and blog post, to be posted shortly.
September is truly a busy period in the yearly cycle of ISBgroup, and this year is no exception. We are in the middle of our main and most advanced course – TBMT42, Systems biology, digital twins, and AI – there are lots of applications with deadline now, and lots of travels. More specifically, Monday, we submitted two applications (to internal ranking for KAW, and one as coordinator), and Tuesday (i.e. yesterday), we submitted three: two to EU (also here one as coordinator) and one postdoc application. And now a couple of intensive travel days commence. Today, I have a popular science lecture at Campus US, here in Linköping (see schedule and title below). Tonight, I go to Stockholm, for a lecture at the SciLifeLab group leader retreat on Thursday, and on Friday, I give a lecture in the Food day, in Malmö. Finally, on Monday-Tuesday, next week, I am in Örebro, to present and network at X-HiDE’s annual retreat. Links and more info to these and all other public appearances in the next couple of months is available on our home page.
Today, December 6, I, Gunnar Cedersund, am giving a lecture in a workshop arranged by the Swedish Research Council (VR). The workshop deals with 3R, and this year’s focus is on one of the “Rs”: “Replacement” of animal experiments. I was invited to give a lecture, because I have received a grant from VR’s dedicated call on 3R.
So, I presented the essence of this project, with a presentation with the same title as the research project: “Scaling from microphysiological systems to humans using scalable digital twins”. The basic idea is that our digital twins for individuals can be scaled down to e.g. a two-organs-a-chip, where a little liver and pancreatic spheroid are connected to each other (Casas et al). This downscaled twin can then be used to interpret data, understand mechanisms ,and plan new experiments on the experimental level. Apart from this, the insights entered into the down-scaled twin can be used to scale the twins back up to the human level. This latter step is called translation, and it leads to the last two steps: regulatory approval and clinical implementation. I talked about all of these steps, and also about some more general issues regarding moving this forward.
In particular, I raised the importance of taking a holistic approach, e.g. by refunding the Swedish 3R-centre, the importance of making it easier to use alternative approaches, e.g. by the creation of new core facilities, and on the importance of creating new incentives and reducing barriers for individual scientists, e.g. by including the development of more realistic experimental systems as a key criteria when evaluating research grants.
There is a new chance to hear about our digital twins. This time it is in connection to the project MeDigiT, on Medical Digital Twins, which involves us, the groups of Tino Ebbers and Jonas Lanz, as well as e.g. our spin-off company SUND sound medical decisions, the company AMRA medical, etc. We speak today at the Innovation week, at 11.10-11.50 in the hospital building of Linköping University hospital. Link to more info about the entire Innovation day today. Welcome! 🙂
