Dose Response of Bumetanide on Aquaporins and Angiogenesis Biomarkers in Human Retinal Endothelial Cells Exposed to Intermittent Hypoxia.

Sibel Guzel,Jacob V Aranda,Charles L Cai,Kay D Beharry

doi:10.3390/ph14100967

Sibel Guzel, Jacob V Aranda + Show 2 more

Open Access

https://doi.org/10.3390/ph14100967

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Abstract

Aquaporins (AQPs) are important for regulating cellular water, solute transport, and balance. Recently, AQPs have also been recognized as playing a key role in cell migration and angiogenesis. In the retina, hypoxia induces vascular endothelial growth factor (VEGF), a potent angiogenic and vascular permeability factor, resulting in retinal edema, which is facilitated by AQPs. Bumetanide is a diuretic agent and AQP 1–4 blocker. We tested the hypothesis that bumetanide suppression of AQPs ameliorates intermittent hypoxia (IH)-induced angiogenesis and oxidative stress in human microvascular retinal endothelial cells (HMRECs). HMRECs were treated with a low-dose (0.05 µg/mL) or high-dose (0.2 µg/mL) of bumetanide and were exposed to normoxia (Nx), hyperoxia (50% O2), or IH (50% O2 with brief hypoxia 5% O2) for 24, 48, and 72 h. Angiogenesis and oxidative stress biomarkers were determined in the culture media, and the cells were assessed for tube formation capacity and AQP-1 and -4 expression. Both doses of bumetanide significantly decreased oxidative stress and angiogenesis biomarkers. This response was reflected by reductions in tube formation capacity and AQP expression. These findings confirm the role of AQPs in retinal angiogenesis. Therapeutic targeting of AQPs with bumetanide may be advantageous for IH-induced aberrant retinal development.

Highlights

Retinopathy of Prematurity (ROP) has become the leading cause of preventable childhood blindness throughout the world, as the quality of neonatal care has improved the survival of very preterm infants [1]
We examined the effects of low and high doses of bumetanide on human microvascular retinal endothelial cells (HMRECs) exposed to IH to test the hypothesis that bumetanide reverses intermittent hypoxia (IH)-induced angiogenesis and oxidative stress via AQP
Levels of 8-isoPGF2α progressively increased in the placebo saline group exposed to Hx and IH, causing them to peak at 72 h

Summary

Introduction

Retinopathy of Prematurity (ROP) has become the leading cause of preventable childhood blindness throughout the world, as the quality of neonatal care has improved the survival of very preterm infants [1]. Decades of research dedicated to maximizing the survival and the minimizing complications of ROP have helped optimize the management of oxygen supplementation for premature infants [2]. If the second phase leads to a significant amount of fibrovascular proliferation and is left untreated, exudative, tractional, or combined type retinal detachment can occur [2]. Such vascular development is a product of astrocyte interactions and trophic factor gradients established by glia and retinal ganglion cells [6]

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