Regenerative Medicine Utrecht


Petra de Graaf in Magazine UMC&ZO

“You have to be able to pee whenever you want and to hold if you do not want to,” says researcher Petra de Graaf. Yet that is exactly what patients with a obstructed urethra often cannot do. This obstruction can be surgically corrected, but with current methods not without complications. That is why Petra is searching for a more effective treatment: make use of the bodies regenerative capacity.

In addition to men with a obstructed urethra, there are boys whose urethra does not extend to the tip of the penis. This is called hypospadias. As a result, among other things, they cannot urinate well. Both conditions can be corrected by surgery. Sometimes extra tissue is needed. For this, skin or buccal mucosa (lining of the cheek) is often used. The biggest disadvantage of this solution, however, is that only the urethra is repaired, not the surrounding corporal body. As a result, a narrowing or dilation of the urethra can occur again.

Healthy tissue
Petra therefore wants to make tissue that much more than skin and cheek mucosa resembles the tissue of the urethra and the erectile body surrounding the urethra (the corpus spongiosum). Healthy tissue is needed, as we have to study how the cells behave and organize themselves. This tissue comes from the transgender clinic of the VUmc: from transwomen.

She has discovered how the different layers of the corpus spongiosum are organized. There are many blood vessels close to the urethra, forming the vascular bed, supplying urethra and corporal cells with nutrients. She now tries to engineer that vascular bed by allowing blood vessel cells to grow in a gel.

Next stage
In a next stage she will investigate how stem cells from the adipose tissue can develop into all cell types needed (urethra, vessels and corporal tissue). With a urethroplasty, tissue could then be used originally grown out of a tiny amount of fat tissue of the patient. However, it takes several weeks to grow this tissue. Ideally she wants to develop material that is inserted into the body and that captures stem cells to make a new urethra.

Petra is originally a chemist and it has always been her fascination to contribute to better health solutions. When she started her urological research she did not know the impact of urinary problems on the quality of life of patients: “Breaking that taboo gives me an extra drive.”