329 - Comparative Histological Analysis Between Caffeine and Azithromycin Treatments in an Ovine Model of Neonatal Hypoxic-Ischemic Encephalopathy Aimed at Low Resource Settings

Poster Number: 329
Publication Number: 329.3138

Background: Neonatal hypoxic-ischemic encephalopathy (HIE) places a significant socioeconomic burden in low- and middle-income countries (LMICs), where nearly 96% of affected infants reside. Currently, LMICs lack alternative therapies. Both azithromycin and caffeine show potential as an economical and readily available medication for managing HIE.

Objective: We aimed to investigate and compare the potential of perinatal caffeine and azithromycin administration as a therapeutic strategy for managing neonatal HIE.

Design/Methods: In two distinct experiments, 76 lambs (141-143 days of gestation) of both sexes were exposed to severe global hypoxia-ischemia using an acute umbilical cord occlusion (UCO) model. In the azithromycin trials, ewes were randomly assigned to receive either 2 g intravenous azithromycin treatment (azithromycin, A), n=21, or a placebo (placebo, P), n=13, immediately before injury. Following resuscitation, ewes received 30 mg/kg azithromycin, followed by two additional 15 mg/kg IV azithromycin doses at 24 and 48 hours of life. In the caffeine experiment, ewes were randomly assigned to receive either 1 g intravenous caffeine citrate (caffeine, caf), n=21, or a placebo, n=21, immediately before injury, with their lambs subsequently receiving 20 mg/kg caffeine citrate following resuscitation (high dose,HD) and 10 mg/kg/day for two days (low-dose,LD). The control group included naive animals, n=6. All experimental groups were compared. At six days post-UCO, we evaluated three white matter regions (PVWM, SCWM1, and SCWM2) and four gray matter regions (Ctx1, Ctx2, Caud, Put).

Results: In azithromycin-treated animals, there was a notable increase in mature oligodendrocytes stained with CC-1, and a higher volume of MBP-positive fibers in all white matter tracts (PVWM, SCWM1, and SCWM2) compared to the placebo (Fig. 1A). LD-caffeine-treated animals exhibited neuronal loss (NeuN) in the cortex of the first parasagittal gyrus (Ctx2) and decreased cellular death (Caspase-3-positive cells) in the caudate, putamen, PVWM, and SCWM1 compared to the placebo group (Fig. 1B). Decreased Iba-1 positive microglial cells were observed in Ctx1 (Fig.1B) for both.

Conclusion(s): The study demonstrates that azithromycin and LD-caffeine may show promise as potential neuroprotective agents after HIE with each agent exhibiting distinct effects on white and gray matter. Additional research is needed to evaluate a wider range of treatments for managing HIE in newborns.