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Press release


New muscles for the bladder: clinical trial evaluates stem cell therapy for congenital incontinence

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Joint press release of the BIH and Charité together with the MDC

Every year in Germany, around seven boys are born with an incompletely formed urethra and urethral sphincter. These children often remain incontinent. In a clinical trial, researchers from Experimental and Clinical Research Center (ECRC), a joint institution of Charité and MDC, want to find out whether a stem cell transplant could help them. The trial has been awarded approximately €3.3 million in funding from the Federal Ministry of Education and Research (BMBF). The BIH Spark programme of the Berlin Institute of Health (BIH) at Charité supported the project with €1 million on its way from the lab to the clinic.

There are over 8000 known rare diseases, affecting more than 30 million people in Europe alone. Developing interventions for these mostly still untreatable diseases represents an important challenge for society and therefore to researchers. One such condition is epispadias, in which a developmental abnormality results in an abnormal position and splitting of the urethra and incomplete development of the urethral sphincter. In Germany, only around seven boys and even fewer girls are born with this condition every year. It is associated with significant psychological stress, because although the externally visible malformation can be treated with surgery, in the case of the urethral sphincter this is unfortunately not so straightforward. "As a result, these children often suffer from lifelong incontinence, which causes considerable psychological stress for affected individuals and their families," says Prof. Dr. Simone Spuler from the ECRC, a specialist in stem cell and muscle research. "So we considered how we could use our expertise to help them."

The research team led by Prof. Spuler had developed a method that allowed them to isolate regeneration-capable muscle stem cells from muscle tissue. "We take a biopsy, a tissue sample, from the thigh and from this we isolate muscle stem cells. We then propagate these cells many times over and inject them directly into the defective area of the urethral sphincter muscle." In rats, this caused a new sphincter muscle to develop, one that was actually functional. Because their altered immune system tolerated human cells, the same result was achieved with human muscle stem cells.

"But despite these encouraging results, we couldn't begin a clinical trial right away with real patients because there are strict regulations in place," the researcher explains. "In humans, we're only allowed to use cells produced in a pharmaceutical process in line with good manufacturing practice, or GMP. Setting up a process like this is very complex." Cells produced under GMP conditions are first used in an animal model for preclinical safety testing. Regulatory authorities – in Germany the Paul Ehrlich Institute – stipulate that only specially accredited laboratories are permitted to carry out the animal experiments for a clinical trial. These labs must comply with good laboratory practice (GLP). In the search for a GLP lab that also had microsurgery capabilities – allowing the muscle stem cells to be transferred into the rat sphincter – the researchers found what they were looking for in the USA. "There was a lab that met the criteria about 300 km east of Chicago, in the heart of Michigan," says Prof. Spuler. "To explain to the team there exactly what we had in mind, we had to make several trips to the USA. The preparations, the necessary familiarisation and the conducting of experiments were all extremely time-consuming and expensive. Without the support of the BIH Spark programme, we could never have done it!"

BIH made €1 million available to Prof. Spuler's muscle research team. "This is exactly in line with our purpose," explains Prof. Dr. Christopher Baum, chairman of the Board of Directors of BIH and Chief Translational Research Officer of Charité. "We want to help researchers take their results from the lab to patients and in this way support clinical translation. This is how we turn research into health." Dr. Tanja Rosenmund, the head of the BIH Spark programme, is also enthusiastic. "The reason the epispadias project is so exciting is that, if it succeeds, it will open up many other possibilities. Incontinence is a widespread problem, as is muscle weakness generally. So we hope that this funding will pave the way for many other studies."

Now that the results in the USA have demonstrated that the transplanted muscle stem cells could prevent incontinence in rats and have also thoroughly confirmed the safety of the cell product, the clinical trial can go ahead. 21 boys aged between three and seventeen will receive treatment at the university hospitals in Ulm and Regensburg, where Prof. Dr. Anne-Karoline Ebert and Prof. Dr. Wolfgang Rösch lead centres for Pediatric urology. The trial will take place on a placebo-controlled, randomised and double-blind basis. This means that a randomly selected five boys out of the group of 21 will be given a placebo (salt solution) instead of their own muscle stem cells. Neither the clinicians nor the patients will know which five these were until the end of the trial. "We have to do this to generate scientifically sound results," explains Prof. Spuler. "If the analysis of data shows that the children who received the cell injection are doing better than those who were given the placebo, those who didn't get the cell injection can of course be given it afterwards. This is possible because the isolated muscle stem cells can be stored without a problem by deep-freezing them." The first patient will be treated in a few months' time.

About Charité – Universitätsmedizin Berlin 
Charité – Universitätsmedizin Berlin is one of the largest university hospitals in Europe, offering 3,001 beds and boasting approximately 100 departments and institutes spread across 4 separate campuses. With a total of 19,400 members of staff employed across its group of companies (16,391 of which at Charité), the organization is one of the largest employers in Berlin. At Charité, the areas of research, teaching and medical care are closely interlinked. 4,707 of its employees work in the field of nursing, with a further 4,693 in research and medical care. Last year, Charité treated 132,383 in- and day case patients, in addition to 655,138 outpatients. In 2020, Charité recorded a turnover of approximately € 2.2 billion (including external funding and investment grants) and set a new record by securing € 196 million in external funding. Charité’s Medical Faculty is one of the largest in Germany, educating and training more than 8,600 medical, dentistry and health sciences students. Charité also offers 577 training positions across 10 different health care professions. Within the field of academic medicine, Charité’s priorities are highlighted by its main areas of research focus: infection; inflammation and immunity including COVID-19 research; cardiovascular research and metabolism; neuroscience; oncology; regenerative therapies; and rare diseases and genetics. Examples of the work conducted by Charité researchers include involvement in 28 DFG Collaborative Research Centers (of which six are led by Charité), three Clusters of Excellence (of which one is led by Charité), 9 Emmy Noether Independent Junior Research Groups, 14 European Research Council grants and 9 European collaborative projects (coordinated by Charité). Research at Charité


Experimental and Clinical Research Center (ECRC)


Markus Heggen
Press Spokesperson
Charité – Universitätsmedizin Berlin
t: +49 30 450 570 400

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