Radboud university medical centre (Radboudumc) in Nijmegen, the Netherlands aims to have a significant impact on healthcare for patients. The hospital’s motto is ‘from molecule to man to population’. It has a global reputation as an emerging center of excellence for advancing the treatment of many diseases and collaborates in many international research projects. Researchers from the Intensive Care (IC) Department are exploring the number one cause of death in the IC – Sepsis – a resilient infectious syndrome with a mortality rate of 30%. Severe cases can cause organ damage or failure. New insights into the emergence of sepsis could help us find effective new therapies. With long term sample storage essential in the success of these now globally integrated studies, VIP ECO Freezers are a fundamental resource in the research.
Researchers have looked for adjunctive treatments effective against sepsis for many years and the pharmaceutical industry has invested millions in developing potential medicines, but until now, this has not delivered any positive results. Despite considerable improvements in supportive care, such as fluid administration, vasopressor use, and mechanical ventilation, none of the candidate adjunctive treatments developed so far have ever reduced mortality from the disease. Matthijs Kox, Assistant Professor at the IC Department and his team of 15 researchers are exploring the immunological aspects of sepsis. They think that immunostimulants could be a novel effective treatment for patients with sepsis in the not too distant future.
Progression of Sepsis
There are two different immunological phenotypes in sepsis. The hyperinflammatory phenotype is characterized by a strongly reactive immune system, frequently accompanied by low blood pressure and high heart rate. This can be counteracted with supportive medication, such as fluids and vasopressors. The second phenotype, known as immunoparalysis is characterized by an exhausted immune system that cannot fight against (secondary) infections. Sepsis researchers are increasingly aware that patients with this latter phenotype are particularly vulnerable and likely to die. Hence, immunostimulant medicines might be useful in treating the disease. Supportive care in IC patients can help prevent deaths by supporting vasopression, breathing, and heart function. Furthermore, it includes medication such as antidiuretics and antibiotics. Despite this, many patients can still develop immunoparalysis. As such, IC physicians then not only have to deal with primary infection, but also with secondary infections that can lead to organ failure (in the kidneys, heart or lungs), and may contribute to mortality.
Dawn of personalized medicine
A step forward in clinical practice would be to assess if the patient exhibits the hyperinflammatory- or immunoparalytic phenotype, and to also consider the heterogeneity within sepsis patients. The goal is to identify which therapy or medicine has the most chance in effective treatment of the individual clinical case.
“We aim to bring personalized medicine for sepsis into clinical practice,” remarked Matthijs Kox. “We are researching novel markers that can identify the immunological phenotype of sepsis patients. Towards this, we work on different levels: diagnostics; treatment; fundamental research into underlying mechanisms; and research in healthy volunteers and sepsis patients. The translational nature of this research, help in the interpretation of the results and contribute towards solving the puzzle that eventually will hopefully lead to new, effective medicines.
A step between animal-model and patient
An important trophy amongst Radboudumc’s Researchers is the human endotoxemia model, which is only operational in a few centres worldwide. “This model forms an ideal stepping stone between animal experiments and patients with sepsis. It can specifically show how the human immune system is influenced by medication, in vivo in humans, before making the step to actual patients,” said Matthijs Kox. “In the model, healthy participants are injected with a lipopolysaccharide (LPS). This so-called endotoxin is a macromolecule in the outside membrane from Gram-negative bacteria.
The immune system reacts to the LPS as if it was a regular bacterium, but because it is a dead form of microbe and not actually live, there is no bacterial replication. Therefore, it is a very safe model in which a controlled immune reaction can be induced. After the administration of LPS, the participants become temporarily sick, with symptoms such as raised temperature, faster heartbeat, lower blood pressure and flu’- like symptoms, such as chills and headaches. Furthermore, they exhibit sequential changes in the immune system that can be characterized by measuring levels of specific inflammation molecules, called cytokines, in the blood. With this model, different immunomodulatory interventions are tested to explore if there is a positive or negative effect on the immune reaction. The beauty of this model is that you can study both immunological phenotypes of sepsis, hyperinflammation and immunoparalysis.” “Alongside measuring circulating levels of inflammatory cytokines, our research team also apply other techniques, such as a flow cytometry, which is used to explore expression of proteins in and on live cells and quantitative polymerase chain reaction (qPCR) to evaluate gene expression,” explained Jelle Gerretsen, Research Technician at the Radboudumc. “We also employ in vitro cell work, which is carried out in the laboratory of Internal Medicine, because we don’t have any possibilities for cell culture here.”
More freezing space
With the growth in the number of studies into sepsis, some of which are carried out in collaboration with pharmaceutical companies, more freezing space is required for long-term storage of all the samples at the IC Department (the samples require storage for a minimum of five years and up to fifteen). To provide extra capacity, a new, VIP ECO (MDF-DU700VH) -86°C Freezer was purchased for the Department.
“It is vital that our systems always work well. Performing an LPS study is very labor-intensive and expensive. It is enormously hard work, requiring months of preparations and intricate logistics,” said Jelle. “Digital temperature registration is an absolute must for our own research and for the approximately 20 commercial clinical trials in which we participate.
The VIP ECO ULT Freezer (MDF-DU700VH) is the first freezer that the Radboudumc. Intensive Care Department purchased. “We are very content with our freezer supplier, PHC Europe B.V. We have never had any problems with their products,” said Matthijs. “Maybe in the near future, new PHCbi products will also be purchased, because until now we are satisfied with their products.”