RT Journal Article SR Electronic T1 Dose-dependent effects of netarsudil, a Rho-kinase inhibitor, on the distal outflow tract JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.01.17.909101 DO 10.1101/2020.01.17.909101 A1 Si Chen A1 Susannah Waxman A1 Chao Wang A1 Sarah Atta A1 Ralitsa Loewen A1 Nils A. Loewen YR 2020 UL http://biorxiv.org/content/early/2020/01/24/2020.01.17.909101.abstract AB Purpose To characterize the effects of netarsudil on the aqueous humor outflow tract distal to the trabecular meshwork (TM). We hypothesized that netarsudil increases outflow facility in eyes with and without circumferential ab interno trabeculectomy (AIT) that removes the TM.Methods 64 porcine anterior segment cultures were randomly assigned to groups with (n=32) and without circumferential AIT (n=32). Cultures were exposed to 0.1, 1, and 10 μM netarsudil (N= 8 eyes per concentration). For each concentration, IOP and vessel diameters were compared to their respective pretreatment baselines. Outflow tract vessel diameters were assessed by spectral-domain optical coherence tomography (SDOCT) and rendered in 4D (XYZ time-series).Results Netarsudil at 1 μM reduced IOP in both eyes with TM (−0.60±0.24 mmHg, p = 0.01) and in eyes without TM (−1.79±0.42 mmHg, p<0.01). At this concentration, vessels of the distal outflow tract dilated by 72%. However, at 0.1 μM netarsudil elevated IOP in eyes with TM (1.59±0.36 mmHg, p<0.001) as well as in eyes without TM (0.23±0.32 mmHg, p<0.001). Vessels of the distal outflow tract constricted by 31%. Similarly, netarsudil at a concentration of 10 μM elevated IOP both in eyes with TM (1.91±0.193, p<0.001) and in eyes without TM (3.65±0.86 mmHg, p<0.001). At this concentration, outflow tract vessels constricted by 27%.Conclusion In the porcine anterior segment culture, the dose-dependent IOP changes caused by netarsudil matched the diameter changes of distal outflow tract vessels. Hyper- and hypotensive properties of netarsudil persisted after TM removal.