TGFB1 and diabetic kidney disease: Sharma et al. examined the immunoreactive TGF-β content in renal blood and urine, and demonstrated that diabetic patients produced TGF-β in their kidneys, but that non-diabetic patients extracted circulating TGF-β from their kidneys, suggesting that increased renal TGF-β production may be an important manifestation of diabetic kidney disease [13].