In memory of Björn Wiman, 1942-2026

Björn began his medical studies at Karolinska Institutet (KI) in 1969 and received his Bachelor of Medical Sciences degree in 1971. Alongside his studies, he conducted research in Per Wallén’s group on fibrinolysis, a process central to the regulation of blood clot formation, wound healing and infection. When Wallén was appointed professor in Umeå, Björn moved with the research group. There, in the student corridor where they both lived, he met his future wife, Annika. In 1973, he completed his doctorate with a thesis on plasminogen, supervised by Professor Per Wallén. He later also became a specialist in clinical chemistry. 

Björn’s research centred on fibrinolysis, initially on plasminogen and its activation, the subject of his thesis. He went on to discover that fibrin stimulates the plasminogen activator tPA, which converts plasminogen into the active enzyme plasmin. From 1977 to 1978, Björn undertook a postdoctoral fellowship in Leuven, Belgium, under the leadership of Professor Marc Verstraete, where Björn worked closely with Désiré Collen on antiplasmin and plasmin. Their collaboration continued for many years, and they became close friends. Björn’s discovery of the role of fibrin in fibrinolysis contributed to the development of tPA as a fibrinolytic drug for dissolving blood clots in the coronary arteries during myocardial infarction. Collen played a central role in this work and, in close collaboration with the pharmaceutical industry, developed recombinant tPA (rtPA). Björn established his own research group in Umeå, but in 1982 he was recruited to Stockholm to conduct research at KI and to serve as Senior Consultant in Clinical Chemistry at Karolinska University Hospital. He became Professor of Coagulation and Clinical Chemistry in 1990 and, for a period, also served as head of Clinical Chemistry at Karolinska University Hospital and deputy head of the then Department of Laboratory Medicine at KI.

Together with Mats Rånby and colleagues, Björn developed a new and sensitive method for measuring tPA activity in 1983. Using this method, they became the first in the world, that same year, to demonstrate the presence of the specific inhibitor plasminogen activator inhibitor 1 (PAI-1) in human blood — in a blood sample Björn had taken from himself. In clinical studies carried out in collaboration with Anders Hamsten, Margareta Blombäck and others, they showed in 1985 that young men who had suffered myocardial infarction had elevated levels of PAI-1. Together with Rånby, Björn also developed a method in 1986 for measuring soluble fibrin, drawing on Björn’s discovery that soluble fibrin strongly accelerates the tPA-mediated activation of plasminogen to plasmin. Later, Björn, Sixten Bredbacka and colleagues showed that this assay could be used to predict multiple organ failure in patients requiring intensive care. In 1987, Björn found that PAI-1 was bound to a carrier protein in plasma. The interactions between tPA and PAI-1 were subsequently mapped in detail, as were the structure and function of PAI-1. In collaboration with Måns Ullberg, it was shown that plasminogen binds to certain bacteria and contributes to their virulence. In later years, Björn also returned in his research to antiplasmin.

Björn was an accomplished biochemist who set exacting standards for himself and for his colleagues. As supervisor to ten doctoral students, a much-appreciated teacher on the medical programme and a generous source of support for younger colleagues, he left a deep and lasting impression. His small, close-knit research group was characterised by loyalty, rigour and focused work, and the barbecue evenings in Björn and Annika’s garden became cherished occasions. Family was very important to Björn. He spoke of Annika and the family with warmth and pride.

Taken together, Björn Wiman’s research made a major contribution to our understanding of the fibrinolytic system, its function and regulation. It also helped lay the foundations for the development of an important fibrinolytic drug first used in the treatment of myocardial infarction, and now widely used in the treatment of ischaemic stroke and pulmonary embolism. 

We remember Björn with gratitude, respect and warmth.

For all colleagues and coworkers Tomas L. Lindahl, Margareta Sten-Linder, Anna Ågren, Håkan Wallén and Jovan Antovic