In:
SLEEP, Oxford University Press (OUP), Vol. 47, No. Supplement_1 ( 2024-04-20), p. A18-A18
Abstract:
Chronic obstructive pulmonary disease/obstructive sleep apnea (COPD/OSA) overlap syndrome is characterized by chronic sustained hypoxemia due to COPD and superimposed intermittent hypoxemia due to OSA, and is associated with poor clinical outcomes related to the severity of hypoxemia. Overlap hypoxia (OH) combining sustained hypoxia and intermittent hypoxia (IH) causes an elevation in serum LDL cholesterol (LDL-C) and hepatic malondialdehyde, a marker of oxidative stress. The use of liver organoids (spheroids) cultured in hypoxia preserves liver-specific variability in tissue oxygenation. We aimed to determine how malondialdehyde and LDL-C uptake were impacted by OH in liver spheroids. Methods HepG2 cells were seeded into wells of round-bottom ultra-low attachment microplates to encourage spheroid formation. Media was changed 1:1 every other day for a total of 8 days. The spheroids were then pipetted into microplates with gas-permeable membranes. In a subset of wells, half the media was replaced by reconstituted LDL-DyLight 550, a conjugated human LDL-C which fluoresces upon endocytosis. Then, the spheroids were placed into one of three hypoxic environments using an OxyCycler C42 Dynamic O2 and CO2 controller: normoxia (16% O2 and 5% CO2), IH (O2 cycling between 16% and 2.5% every 3 min, constant 5% CO2), or OH (O2 cycling between 11.5% and 2.5% every 3 min, constant 5% CO2). After 4 hours, media and spheroids were collected for quantification of malondialdehyde (n=4 pooled samples/group), and spheroids with LDL-DyLight 550 were examined for fluorescence (n=24 spheroids/group). Results There were no morphologic differences among the groups after hypoxic or normoxic exposures. Malondialdehyde was increased in both hypoxic spheroid groups, though more in OH (RA: 2.9±1.4 µM; IH: 7.4±3.7 µM, p=0.005 vs RA; OH: 9.6±4.8 µM, p & lt; 0.001 vs RA). LDL-C uptake was reduced by 28.4% in OH relative to RA (p=0.003). No effect was noted in IH (p=0.863). Conclusion Culture of hepatocyte-derived spheroids in hypoxic environments is feasible. OH in spheroid culture increases an important marker of oxidative stress, and reduces LDL-C uptake. These results echo previous animal-based data. Future experiments are intended to understand underlying mechanisms. Support (if any) This project was supported by grants NIH K08HL143140 and UCSD RG104448.
Type of Medium:
Online Resource
ISSN:
0161-8105
,
1550-9109
DOI:
10.1093/sleep/zsae067.0040
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2024
detail.hit.zdb_id:
2056761-3
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