A passionate mentor looks back: Professor Geir Christensen retires

Just one month shy of 38 years with the Institute for Experimental Medical Research (IEMR), Professor Geir Christensen adds the word Emeritus to his title. To everyone at IEMR and to Norwegian heart research, it is the end of an era.  

Text: Marianne Alfsen/Felix Media
Photo: Fredrik Naumann/Felix Features

The molecular understanding of how the heart functions is fundamental.
Geir Christensen

“I still have PhD students to supervise,” the fresh retiree tells us as he shuffles neat stacks of paper around his desk, giving away one of his true passions from the get go. Two blue sofas at an angle in the corner of the office are bathed in sunlight. They do not look worn, but they are – by numerous PhD students over the course of decades.

“One of the most meaningful things I have done is to supervise nearly 40 PhD students. I look forward to each and every meeting. Seeing them go on to do great things in their further careers has fueled my drive to continue coaching, says Christensen, who is only four days into his retirement when we meet him.

The leaving party is over, his portrait already hung in IEMRs ‘hall of fame’ – the main meeting room walls, where all former heads of department and group leaders at IEMR are honoured for posterity. 

“I am the first to have a portrait photo taken, rather than being painted. That suits me fine, says Christensen, who at the time of his retirement, in March 2024, led the research group on cellular and molecular biology of myocardial hypertrophy and heart failure, one of seven research groups at IEMR.

Athiramol Sasi (Athira) from India is studying fibrosis (stiff heart) samples. Geir Christensen will continue to be her supervisor.

A distinguished career

The paintings had to be shuffled around, as there was no doubt where Christensen’s photograph had to be hung: Above the chair by the wall, where he for years has offered his insight in departmental meetings. Humbly and passionately, as has been his way since he first came to IEMR as a PhD student in 1986.

“There are three things that characterise Geir Christensen: He is a mentor to students and a man who fosters academic cooperation, as well as being one of the most prominent heart researchers in Norway for several decades. For that he received the Heart Prize presented by King Harald V,” says Head of Department at IEMR, Mathis Stokke.

“Geir is driven by curiosity for the basic properties of nature. Through almost four decades and a substantial body of research, he has continued to uncover new aspects,” Stokke adds.

Hormones and molecules

Always the teacher; when asked to explain his research interests, Geir Christensen takes out a pen and starts sketching a timeline on the back of a discarded document.

“My interest in physiology, in particular circulation, began in medical school,” he begins. From there, it was only a hop and a skip to heart research. 

Fascinated by the work of former IEMR director Fredrik Kiil on kidney function, he contacted the esteemed professor. Kiil introduced him to a tiny building block in the human circulation system that also became the foundation stone for his own career as a researcher: the atrial natriuretic peptide (ANP) hormone.

“Why don’t you study this cardiac hormone, and its effect on circulation, it could be important, he said to me. It turned out to be a bloody good idea. That’s how I got into heart research,” says Christensen, and offers one of his frequent smiles and quiet laughs.

The importance of basic research

“I studied how this hormone was secreted from and regulated by the heart,” explains Christensen. ANP regulates the body’s water balance and blood pressure. To put it simply, the more ANP released, the more you pee. 

Today, that very hormone has become crucial to diagnostics as well as treatment of heart disease. 

“We did with ANP what we do best at this institute: Basic research,” he says and leans forward. His body language tells us we are heading into another territory where his passion runs high: 

“Translational research,” he calls it. Building the bridge between basic research and the understanding of the intricate workings of the human body, and clinical research where the tools for diagnostics and treatments are developed. The latter gets more headlines – and funding. The former is often left to constantly justify its reason for being.

“But you cannot have one without the other. Understanding how the body works through basic research is necessary in order to develop clinical diagnostics and treatment,” Christensen says, and uses the ANP hormone as an example. Christensen and other researchers studying ANP discovered that if the heart is overloaded, it releases ANP. Such basic understanding made it possible to start using ANP as a biomarker for heart disease.

Left: Geir Christensen explains what causes fibrosis. Right: Geir Christensen studying the portraits of some of the nearly 40 PhD students he has supervised over the years.

Animal models and methodology

Developing the methodology for research is also high on one of Geir Christensen’s list of passions – ever since he went to the US to study molecular cardiology for his postdoctoral work in the late 1990s.

“The molecular understanding of how the heart functions is fundamental,” says Christensen.

He went home to Norway, became a professor and used the knowledge gained in the US to build cellular and molecular methodology to be used by the researchers at IEMR.

Geir Christensen’s list of merits also include being an early mover in the development of animal models, to simulate and study the development of diseases – the true link between basic and clinical research. In collaboration with the heart surgeon and fellow group leader at IEMR, Theis Tønnessen, he started inducing myocardial infarctions in mice and rats, to follow the flow of ANP.

“We have even developed an animal model for what ails the Norwegian king Harald, for which he has had surgery twice: a narrow heart valve, aortic stenosis,” says Christensen, explaining: “We can’t make the heart valve of rats stiff to create aortic stenosis the way it happens in humans. To simulate a narrow heart valve, we put a ring around the main artery, where it exits the heart.”

“We will struggle to fill Geir Christensen’s shoes. Luckily, he will still be around, supervising PhD-students,” says Head of Department at IEMR, Mathis Stokke (left).

Three major research areas

Christensen continues to ink out his timeline on the back of the discarded document.

“When studying ANP, I was interested in the atrial heart chambers. That led me on to atrial fibrillation, which is one of the most common heart diseases for people over the age of 60,” he explains.

“I studied atrial fibrillation with my wife Elisabeth, and we managed to publish in Circulation, and it was cool to be cited in Braunwald’s textbook,” he recalled in his speech to his colleagues.

In the latter part of his career, inflammation of the heart and the resulting fibrosis has been the focus of his research.

“Currently, there is no treatment for fibrosis – a stiff heart. In order to diagnose and treat it, we need to understand why it happens,” he says.  

The last paper he published, in May 2023, before adding “Emeritus” to his title, was a crucial piece of translational research:

“We published a study on a medicine that has never been used before, which reduced cardiac fibrosis in rats. We are not there yet, but the study points in the direction of several ways we can treat cardiac fibrosis that causes a stiff heart, more frequently observed in women. I am so happy I got to contribute to that, together with Maria Vistnes and several other researchers at IEMR. Quite proud, actually,” Geir Christensen says, in a rare moment of self-appraisal – from a man who is always quick to attribute any success to the collaborative effort of his colleagues. Be it IEMR institute leaders, such as Fredrik Kiil, Ole Sejersted, Ivar Sjaastad, Lisbeth Winer and the current head of IEMR Mathis Korseberg Stokke, or the long list of medical researchers and PhD students he has collaborated with during the course of his career. It is obvious that he would prefer it if we could name them all in this article.

Professor Emeritus Geir Christensen.
One of the most meaningful things I have done is to supervise nearly 40 PhD students. I look forward to each and every meeting.
Geir Christensen

Academic collaboration

“I like the idea of contributing to something bigger than myself,” says Christensen. He is not only referring to his medical research in general, but to the collaborative academic institutions he has been instrumental in setting up during his time at IEMR.

“Leaders of the world constantly reinforce or move around national boundaries. In such a world, it is fantastic to be part of an international research community, where those boundaries do not exist,” he says.

In 2002, he secured funding for a Center for Heart Failure Research, to promote collaboration and interaction between all heart research groups within South-Eastern Norway Regional Health Authority (Helse Sør-Øst). But that is not all: He also set up the national PhD school NorHeart, introducing PhD students to methodology within heart research and opening up their minds to cross-sectoral cooperation. NorHeart also organises a yearly scientific conference in Oslo, inviting top international heart researchers to speak.

“IEMR has a great history with regard to the education of young researchers, and I am proud to have been a part of that,” says Christensen.

The road ahead

Four days into his retirement, the Professor Emeritus has yet to map out the next phase of his life:

“Oh, you know, the usual. More time with my family, especially the grandchildren. And more time spent being active in nature and reading,” he says. 

IEMR is a far cry from the group of six or seven physicians Geir Christensen met four decades ago. Today, at any given time, IEMR comprises about 60–70 researchers, not only from medicine but from a host of other disciplines – from physicists to statisticians and molecular biologists. And not least: From the entire world.“IEMR has grown in size and quality. The future for IEMR is bright,” says Geir Christensen.

But one thing is paramount: “Don’t let the constant pressure from some funding bodies for immediate clinical relevance direct you: Never forget basic research.”