Else Kröner-Fresenius-Zentrum (EKFZ)

Tissue sections and their microscopic analysis are essential for the work conducted at the EKFZ for Nephrological Research. To facilitate this, a fully equipped embedding and histology unit is available. For image acquisition, a slide scanner is available. This device can produce both light microscopic and fluorescence microscopic images of entire organs. Unlike classical microscopy, which requires individual images to be painstakingly assembled, slide scanning allows for the capture of the entire organ in a single process. This method also enables systematic analysis using AI-generated algorithms. The slide scanner can process up to 100 histological sections simultaneously.

For detailed imaging, an ultra-high-resolution laser scanning confocal microscope is available. This allows for specific imaging down to the molecular level of individual cells. Additionally, this microscope system enables the visualization of dynamic processes in living cells. It includes a unit that allows cells to be cultured in a special incubation chamber within the microscope, permitting ultra-high-resolution imaging at different time points and locations. A notable feature is the direct connection between the slide scanner and the confocal microscope. This integration allows specific positions within an organ imaged by the slide scanner to be marked and later relocated with the confocal microscope for high-resolution imaging.

At the EKFZ for Nephrological Research, a BD FACSymphony™ multicolor flow cytometer is available. This instrument enables the quantification of up to 30 different antigens on the cell surface as well as within the cell. The technology is employed, for instance, to quantify various stem cell populations in the bone marrow and circulating leukocyte subpopulations and, particularly, in projects investigating the interaction between the kidney, heart, and bone marrow.

At the EKFZ for Nephrological Research, the culture of kidney, heart, and bone marrow organoids has been established. For this purpose, human induced pluripotent stem cells (iPSCs) are cultured over several weeks with various growth factors. Under their influence, small human "organs," called organoids, develop, which contain the different cell types of the kidney, heart, or bone marrow. Heart organoids, for example, can be identified in tissue culture by their ability to begin beating like human hearts. A significant advantage of organoids is that they can be produced in large numbers and that individual genes can be easily modulated to study their function. Additionally, the use of organoids allows for a substantial reduction in the number of animal experiments to an absolute minimum.

Small animal models remain widely indispensable. Many complex disease processes and the interactions between different organs can only be studied in a living organism. This is particularly crucial for projects at the EKFZ that investigate the relationships between the kidney, heart, and bone marrow. Consequently, the EKFZ for Nephrological Research is equipped with a surgery unit. This facility is equipped with an isoflurane anesthesia unit, a video microscope, and an ultrasound device. Additionally, the EKFZ has a clinical-chemical multianalyzer that can measure various clinical-chemical parameters, such as kidney function, from the smallest amounts of blood.

The following surgical procedures have been established at the EKFZ:

• Minimally invasive myocardial infarction surgery
• Unilateral ureteral ligation
• Perivascular carotid injury model
• Skin transplantation
• Kidney transplantation