Human-pluripotent-stem-cell-derived kidney cells (hPSC-KCs) have important potential for disease modelling and regeneration. Whether the hPSC-KCs can reconstitute tissue-specific phenotypes is currently unknown. Here we show that hPSC-KCs self-organize into kidney organoids that functionally recapitulate tissue-specific epithelial physiology, including disease phenotypes after genome editing. In three-dimensional cultures, epiblast-stage hPSCs form spheroids surrounding hollow, amniotic-like cavities. GSK3β inhibition differentiates spheroids into segmented, nephron-like kidney organoids containing cell populations with characteristics of proximal tubules, podocytes and endothelium. Tubules accumulate dextran and methotrexate transport cargoes, and express kidney injury molecule-1 after nephrotoxic chemical injury. CRISPR/Cas9 knockout of podocalyxin causes junctional organization defects in podocyte-like cells. Knockout of the polycystic kidney disease genes PKD1 or PKD2 induces cyst formation from kidney tubules. All of these functional phenotypes are distinct from effects in epiblast spheroids, indicating that they are tissue specific. Our findings establish a reproducible, versatile three-dimensional framework for human epithelial disease modelling and regenerative medicine applications.

BACKGROUND Hypertension is common in autosomal dominant polycystic kidney disease (ADPKD) and is associated with increased total kidney volume, activation of the renin–angiotensin–aldosterone system, and progression of kidney disease. METHODS In this double-blind, placebo-controlled trial, we randomly assigned 558 hypertensive participants with ADPKD (15 to 49 years of age, with an estimated glomerular filtration rate [GFR] >60 ml per minute per 1.73 m2 of body-surface area) to either a standard blood-pressure target (120/70 to 130/80 mm Hg) or a low blood-pressure target (95/60 to 110/75 mm Hg) and to either an angiotensin-converting–enzyme inhibitor (lisinopril) plus an angiotensin-receptor blocker (telmisartan) or lisinopril plus placebo. The primary outcome was the annual percentage change in the total kidney volume. RESULTS The annual percentage increase in total kidney volume was significantly lower in the low-blood-pressure group than in the standard-blood-pressure group (5.6% vs. 6.6%, P = 0.006), without significant differences between the lisinopril–telmisartan group and the lisinopril–placebo group. The rate of change in estimated GFR was similar in the two medication groups, with a negative slope difference in the short term in the low-blood-pressure group as compared with the standard-blood-pressure group (P<0.001) and a marginally positive slope difference in the long term (P = 0.05). The left-ventricular-mass index decreased more in the low-blood-pressure group than in the standard-blood-pressure group (−1.17 vs. −0.57 g per square meter per year, P<0.001); urinary albumin excretion was reduced by 3.77% with the low-pressure target and increased by 2.43% with the standard target (P<0.001). Dizziness and light-headedness were more common in the low-blood-pressure group than in the standard-blood-pressure group (80.7% vs. 69.4%, P = 0.002). CONCLUSIONS In early ADPKD, the combination of lisinopril and telmisartan did not significantly alter the rate of increase in total kidney volume. As compared with standard blood-pressure control, rigorous blood-pressure control was associated with a slower increase in total kidney volume, no overall change in the estimated GFR, a greater decline in the left-ventricular-mass index, and greater reduction in urinary albumin excretion.

A method for monitoring dietary compliance would be useful in treating patients with chronic renal failure (CRF). Nineteen nitrogen balances were measured while patients were eating unrestricted diets containing 6.4 to 15.1 g of nitrogen per day and 14 while patients consumed a 20 to 25 g mixed-quality protein ketoacid-supplemented diet containing 5.2 to 6.6 g of nitrogen per day. Urea nitrogen appearance (U) calculated as the sum of urinary urea nitrogen plus the variation in the body urea pool (using changes in serum urea nitrogen and either the 14C urea space or 60% body weight) was correlated with nitrogen intake (r = 0.84). Both methods gave indistinguishable values for U. Total non-urea nitrogen excretion (NUN) and its components did not correlate with dietary nitrogen. NUN averaged 31.3 +/- 2.1 mg N/kg/day and was not different between the two groups or in patients in neutral compared to those in mildly negative or positive nitrogen balance. Nitrogen balance calculated using estimated U and 31 mg N/kg/day was indistinguishable statistically from measured nitrogen balance. Thus, U varies directly with dietary protein intake and can be estimated using urinary urea nitrogen, SUN, and body weight. Total nitrogen excretion can be estimated accurately as U + 31 mg N/kg/day. From the estimated total nitrogen excretion, dietary compliance of CRF patients in approximately neutral nitrogen balance could be assessed. Furthermore, if nitrogen intake were known, nitrogen balance could be estimated.