Via EurekAlert!: "This paper reports the discovery of one of the first targeted drugs specifically developed to reverse fibrosis and regenerate the kidney. We're optimistic about the benefits, but the real proof will come from clinical testing. ... In the kidneys and other organs, fibrosis develops from normal repair mechanisms that do not stop. Scar tissue slowly builds up and replaces the working cells of the organ. In 2003, [researchers] reported that the destructive fibrosis in mice can be countered by the human protein BMP-7, originally named for its ability to spur bone growth. ... However, the large protein needs to be injected or surgically implanted and, therefore, is not useful for long-term treatment protocols. Probing deeper into the biology of the kidney, they identified the protein Alk3 [and] based on the details about the molecular interaction between the BMP protein and the ALK receptor, [scientists] developed a class of small functional peptides, including THR-123, which then underwent further testing. ... This receptor must be present for the new molecule to function ... Working through the receptor, the molecule suppressed inflammation, cell death and fibrosis formation, as well as reversing established fibrosis and allowing kidneys to regenerate functional cells ... Further experiments showed that the test drug worked even better in the mice when given in combination with ACE inhibitors, the anti-hypertensive drugs now considered a standard therapy for chronic kidney disease which work by targeting another molecular process. ... Targeting the receptor not only stops fibrosis, it removes established fibrosis, and it works in combination with an existing drug used in patients. The next step is to test this molecule in the clinic."