News items ERC Starting Grant awarded to Jeroen de Baaij

17 March 2022

Jeroen de Baaij, kidney researcher the Radboudumc, receives an ERC Starting Grant worth 1.5 million euros. He will use this grant to improve the diagnosis and treatment of severe magnesium deficiencies, which can lead to epileptic seizures and muscle cramps. 

The kidneys determine the mineral balance in the body, including magnesium. In some patients, genetic defects in the kidneys results in a magnesium deficiency. These patients excrete too much magnesium and experience symptoms such as muscle cramps, fatigue, and seizures. Administering oral magnesium supplements is often insufficient to relieve symptoms. 

Jeroen de Baaij has been studying patients with these severe forms of magnesium deficiency for years. Within a large European network, he has identified various genes that cause a magnesium deficiency. Despite these efforts, a significant group of patients remain without diagnosis. He will use the ERC Starting Grant to improve the diagnostic perspective of these patients. De Baaij: "Investigating kidney disease is difficult because we often cannot take biopsies. Therefore, I will study the urine of patients, which contains kidney cells. With this grant, we can examine the functional processes at a single cell level. We will use these analyses to provide a diagnosis to patients with a magnesium deficiency.”

Testing medication on kidneys organoids

Jeroen de Baaij will develop kidney organoids from the urine of patients. The functional processes in these “lab kidneys” are similar to those in human kidneys. De Baaij will use the kidney organoids to study why magnesium is not reabsorbed in people with a severe magnesium deficiency. Moreover, these lab kidneys can be used to test medication.

De Baaij: “I expect that by our analysis of these kidney cells, we will better understand the causes of the magnesium deficiency. This will help us to select the right therapy and test novel medication.” Using fluorescence, a light-emitting signal, the live uptake of magnesium in the kidney can be visualized in mice. This new technique will provide more insight into how the kidney cells absorb magnesium. In time, this will contribute to better treatment.

Important for type 2 diabetes

De Baaij's research now focuses on a small group of patients with a rare genetic disorder that causes magnesium deficiency. But the knowledge he gains may also help other patient groups, such as people with type 2 diabetes. His previous research has shown that twenty percent of people with diabetes in the Netherlands have a magnesium deficiency. “In our study, we focus on a small group of patients, but ultimately we hope to improve the treatment of magnesium deficiency in general." concludes De Baaij.

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Pauline Dekhuijzen

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