JERUSALEM, Aug. 6 (Xinhua) -- A team from Israel's Sheba Medical Center and Tel Aviv University has successfully grown long-term and pure human kidney organoids from tissue stem cells under laboratory conditions, providing a powerful new tool for researchers and possible advanced transplants in the future.

Choosing research models plays a crucial role in deepening the understanding of kidney diseases and developing new therapies. For instance, animals contributed to many discoveries, but they are not always an accurate reflection of human health and disease.

In recent years, organoids have emerged as a promising tool for studying kidney diseases. Despite the name, organoids, grown in the lab from stem cells, aren't miniature organs, but look like three-dimensional hollow balls of cells that closely mimic how the cells behave in the body.

The kidney organoids developed by the Israeli team matured and remained stable for 34 weeks, marking the longest-lived kidney organoid culture to date, as previous organoids broke down within just four weeks, said Sheba Medical Center on Tuesday.

Over the extended culture period, the organoids progressed through stages of creating biological tubes, forming vital kidney structures, including blood filters and urinary ducts, which enabled the researchers to study normal and abnormal kidney development, and test the effects of gene mutations and drug toxicity on fetal kidneys.

This long-term growth sheds light on how kidneys develop and how diseases begin. For example, when the team blocked certain signals in the organoid, they observed birth defects similar to those seen in patients.

The new organoid system also achieved unprecedented purity. In earlier models, the kidney organoids often contained unwanted cell types because they were cultured from pluripotent stem cells that can differentiate into any cell type in the body. In the new study, the organoids are formed exclusively from kidney tissue stem cells, which enables more precise cause-and-effect experiments.

The results have been published in the EMBO Journal.

The researchers said that the new organoids provide "an essentially inexhaustible source of different kidney cells, and a better understanding of their different roles in kidney development and function."

They noted that it also opens the door to regenerative medicine. Kidney tissue grown in the laboratory may be transplanted into the body in the future. ■