Search

Background We previously showed that the presence of a CKD-associated locus in SHROOM3 in a donor kidney results in increased expression of SHROOM3 (an F-actin–binding protein important for epithelial morphogenesis, via rho-kinase [ROCK] binding); this facilitates TGF-b signaling and allograft fibrosis. However, other evidence suggests Shroom3 may have a protective role in glomerular development. Methods We used human data, Shroom3 knockdown podocytes, and inducible shRNA-mediated knockdown mice to study the role of Shroom3 in adult glomeruli. Results Expression data from the Nephroseq database showed glomerular and nonglomerular SHROOM3 had opposing associations with renal function in CKD biopsy samples. In human allografts, homozygosity at rs17319721, the SHROOM3 locus linked with lower GFR, was associated with reduced albuminuria by 2 years after transplant. Although our previous data showed reduced renal fibrosis with tubular Shroom3 knockdown, this study found that glomerular but not tubular Shroom3 knockdown induced albuminuria. Electron microscopy revealed diffuse foot process effacement, and glomerular RNA-sequencing showed enrichment of tyrosine kinase signaling and podocyte actin cytoskeleton pathways in knockdown mice. Screening SHROOM3-interacting proteins identified FYN (a src-kinase) as a candidate.We confirmed the interaction of endogenous SHROOM3 with FYN in human podocytes via a critical Src homology 3–binding domain, distinct from its ROCK-binding domain. Shroom3-Fyn interaction was required in vitro and in vivo for activation of Fyn kinase and downstream nephrin phosphorylation in podocytes. SHROOM3 knockdown altered podocyte morphology, cytoskeleton, adhesion, and migration. Conclusions We demonstrate a novel mechanism that may explain SHROOM3’s dichotomous associations in glomerular versus nonglomerular compartments in CKD

The purpose of this study was to determine the intravenous dose of carbetocin required to produce effective uterine contraction in 90% of females (ED90) undergoing elective Cesarean delivery (CD) under spinal anesthesia.We conducted a double-blind dose-finding study of carbetocin. Forty females undergoing elective CD received carbetocin intravenously upon delivery of the fetus. The dose of carbetocin for each patient was determined according to a biased-coin up-and-down sequential allocation scheme designed to cluster doses close to ED90. The initial dose was 10 μg, with increments/decrements of 5 μg. The anesthesiologist, obstetrician, and patient were blinded to the dose. The obstetrician assessed the uterine tone at one-minute intervals for five minutes after carbetocin administration. In case of unsatisfactory tone, additional uterotonics were administered. The primary outcome was requirement for additional intraoperative uterotonics. Secondary outcomes were postoperative requirement for additional uterotonics within 24 hr of delivery, estimated blood loss and side effects.The ED90 of carbetocin was 14.8 μg (95% confidence interval 13.7 to 15.8). Thirty-seven patients (92.5%) had adequate uterine tone with no requirement of additional intraoperative uterotonics. Two patients (5%) required postoperative uterotonics within 24 hr. The overall mean (SD) estimated blood loss was 786 (403) mL and the overall incidence of hypotension (decrease in systolic blood pressure ≥ 20% baseline) was 37.5%.Based on our study, the ED90 of carbetocin at elective CD is less than one-fifth the currently recommended dose of 100 μg. This study was registered at clinicaltrials.gov (NCT-01651130).