Anyone training on the treadmill in the hypoxia chamber will find themselves looking out of a large window – at a concrete wall. “The view out there used to be trees – now there’s a new building instead,” says Anja Mähler, who has been in charge of the Clinical Research Unit (CRU) at the Experimental Clinical Research Center (ECRC ) since the summer of 2020. It’s a pity for the volunteers, who usually spend long periods training on the treadmill under high-altitude conditions. It would be nicer to be able to look out on something green.
360° video of the hypoxia chamber. © Felix Petermann, MDC
Anja Mähler has been working in the CRU for over ten years – it was there that she wrote her doctoral thesis in nutrition science before supervising various studies and then applying for the most senior post when it became vacant. “I really enjoy the variety of my work,” she says. Rather than being limited to a specific disease, she is involved in studying different disease patterns with a range of interventions, collaborating with lots of experts who continually provide new perspectives. “The equipment in the CRU is unique in the world. I also have a lot of scope to choose how I work. That’s a great motivator,” says Mähler.
A different method behind every door
Anja Mähler’s domain comprises a long corridor, and it seems as though behind every door is a different method. One example is indirect calorimetry, which measures resting energy metabolism. In this process, the volunteer lies under a ventilated hood while the air they breathe out is analysed. “From the oxygen consumed and the carbon dioxide produced, we can calculate the amount of energy converted,” Mähler explains. The CRU team can also measure body composition, carbohydrate and lipid metabolism as well as training effects after exercise regimens at different altitudes in the hypoxia chamber. “Here we can simulate conditions corresponding to an altitude of 4,000 metres,” says the head of the CRU. Researchers are interested not only in training effects but also in the overall effect of the reduced oxygen stimulus on metabolism.
Mähler is particularly proud of the metabolic chamber, in which volunteers can move around and exercise while their energy metabolism is measured. Food is delivered to them through an airlock; a bit like meals being passed through the kitchen hatch to the dining room. Right next door to the chamber, the researchers can monitor the measurements on various instruments. “There are only 17 chambers like this in the world,” says Mähler.
Can lactic acid bacteria help with high blood pressure?
The CRU’s mission is to translate preclinical research findings from the MDC and Charité into clinical research involving real patients. “Our work is characterised by its interdisciplinary nature. We don’t focus on a specific disease – instead we’re interested in both healthy and pathological processes. And we look at these processes on different levels, for instance neurological or cardiovascular,” Mähler explains. The CRU offers a range of methods, such as dietary and exercise interventions, to discover overarching mechanisms that drive disease. The CRU team also recruits volunteers and collects blood and stool samples, which are important to molecular-level analysis – for example relating to the metabolome and microbiome.
One of the five studies currently being carried out at the CRU is a collaboration with the team led by MDC researcher Dominik Müller. In 2017, together with a large research team, he discovered that sodium chloride reduced the number of certain lactic acid bacteria in the gut, affecting immune cells, which are partially responsible for autoimmune conditions and high blood pressure. The research team was also able to show, firstly with mice and then with humans, that probiotics can reduce disease symptoms. Researchers in the CRU are currently investigating how one multi-strain probiotic affects blood pressure. “We’re doing this research with individuals who have an early stage of high blood pressure and don’t yet have any of the resulting conditions, because in the first instance we’re interested in the mechanisms,” explains Anja Mähler. For this reason, the researchers are also measuring how intake of lactic acid bacteria affects the gut microbiome, immune system and metabolism.
More cooperation with the MDC
However, there is still room to expand cooperation with researchers at the MDC: “We’re located here on the Buch campus, but despite being so close, there has been relatively little collaboration so far,” says Mähler. As the new head of the CRU, she wants to change that – for example through the newly established Translational Clinical Study Call, to be published for the first time in January 2021. MDC groups are invited to submit an outline for a proof-of-concept study which is eligible for financial and staff resources. The call is to be issued every year starting in 2021. As a result, more MDC researchers will have the opportunity to get to know the chambers presided over by Anja Mähler – and all that can be achieved with them.
Text: Wiebke Peters