Factors associated with functional arteriovenous fistula at hemodialysis start and arteriovenous fistula non-use in a single-center cohort.

BACKGROUND: The gold standard of commencing hemodialysis with a functional arteriovenous fistula (AVF) is challenging. We aim to review factors associated with functional AVF at hemodialysis start at a tertiary hospital. METHODS: We retrospectively reviewed incident hemodialysis patients or who had AVF creation at a single tertiary hospital from 2011 to 2016. Data was extracted for patient comorbidities, duration from referral to AVF creation and hemodialysis start, estimated glomerular filtration rate (eGFR) at surgical referral, referring nephrologist, events accelerating eGFR decline, and revisions for "failing to mature" AVF to assess factors associated with non-functioning AVF or late AVF creation, using multinomial logistic regression. RESULTS: Two hundred two patients received hemodialysis and 51 had AVF creation but did not dialyze (AVF futility rate 20%). Of these, 133 (66%) commenced hemodialysis with a central venous catheter (CVC) and 69 (34%) with an AVF. Patients with functional AVFs at hemodialysis start were referred earlier than those with non-functional AVFs (median 256 vs 66 days before hemodialysis start, p = 0.001). Age, sex, eGFR at surgical referral, and comorbidities were not predictive of patients with functional AVFs. Events accelerating eGFR decline were associated with an increased incidence of CVC at hemodialysis start (risk ratio (RR) 4.21, 95% confidence interval (CI) 1.96-9.03, p < 0.0001). Referring nephrologists external to our renal unit may be associated with non-functional AVF at hemodialysis start (RR 6.60, 95% CI 1.74-25.13, p = 0.006). CONCLUSIONS: We found that functional AVFs required referral a median of 256 days prior to hemodialysis start and events accelerating eGFR decline increase the incidence of CVC at hemodialysis start. Age, sex, eGFR at surgical referral, and comorbidities did not inform the likelihood of timely AVF creation and evaluation of further predictive pre-dialysis factors is necessary to identify patients requiring early AVF creation whilst minimizing the cost of unnecessary procedures.

Light-focusing human micro-lenses generated from pluripotent stem cells model lens development and drug-induced cataract in vitro.

Cataracts cause vision loss and blindness by impairing the ability of the ocular lens to focus light onto the retina. Various cataract risk factors have been identified, including drug treatments, age, smoking and diabetes. However, the molecular events responsible for these different forms of cataract are ill-defined, and the advent of modern cataract surgery in the 1960s virtually eliminated access to human lenses for research. Here, we demonstrate large-scale production of light-focusing human micro-lenses from spheroidal masses of human lens epithelial cells purified from differentiating pluripotent stem cells. The purified lens cells and micro-lenses display similar morphology, cellular arrangement, mRNA expression and protein expression to human lens cells and lenses. Exposing the micro-lenses to the emergent cystic fibrosis drug Vx-770 reduces micro-lens transparency and focusing ability. These human micro-lenses provide a powerful and large-scale platform for defining molecular disease mechanisms caused by cataract risk factors, for anti-cataract drug screening and for clinically relevant toxicity assays.