Insulin-Like Growth Factor-1 Supplementation Promotes Brain Maturation in Preterm Pigs

• Published in: eNeuro Vol. 10; no. 4; p. ENEURO.0430-22.2023
• Main Authors: Christiansen, Line I, Holmqvist, Bo, Pan, Xiaoyu, Holgersen, Kristine, Lindholm, Sandy E H, Henriksen, Nicole L, Burrin, Douglas G, Ley, David, Thymann, Thomas, Sangild, Per Torp, Pankratova, Stanislava
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 01.04.2023
• Subjects: Animals; Basic Medicine; Brain - metabolism; Cerebellum - metabolism; cortex; developing brain; Dietary Supplements; Female; hippocampus; Humans; IGF-1; IGF1R; Infant, Newborn; Infant, Premature; Insulin-Like Growth Factor I - metabolism; Insulin-Like Growth Factor I - pharmacology; Medical and Health Sciences; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Neurosciences; Neurovetenskaper; New Research; Pregnancy; Swine; cortex; IGF-1; hippocampus; developing brain; IGF1R
• ISSN: 2373-2822; 2373-2822
• DOI: 10.1523/ENEURO.0430-22.2023

Very preterm infants show low levels of insulin-like growth factor-1 (IGF-1), which is associated with postnatal growth restriction and poor neurologic outcomes. It remains unknown whether supplemental IGF-1 may stimulate neurodevelopment in preterm neonates. Using cesarean-delivered preterm pigs as a model of preterm infants, we investigated the effects of supplemental IGF-1 on motor function and on regional and cellular brain development. Pigs were treated with 2.25 mg/kg/d recombinant human IGF-1/IGF binding protein-3 complex from birth until day 5 or 9 before the collection of brain samples for quantitative immunohistochemistry (IHC), RNA sequencing, and quantitative PCR analyses. Brain protein synthesis was measured using labeling with [2H5] phenylalanine. We showed that the IGF-1 receptor was widely distributed in the brain and largely coexisted with immature neurons. Region-specific quantification of IHC labeling showed that IGF-1 treatment promoted neuronal differentiation, increased subcortical myelination, and attenuated synaptogenesis in a region-dependent and time-dependent manner. The expression levels of genes involved in neuronal and oligodendrocyte maturation, and angiogenic and transport functions were altered, reflecting enhanced brain maturation in response to IGF-1 treatment. Cerebellar protein synthesis was increased by 19% at day 5 and 14% at day 9 after IGF-1 treatment. Treatment had no effect on Iba1 microglia or regional brain weights and did not affect motor development or the expression of genes related to IGF-1 signaling. In conclusion, the data show that supplemental IGF-1 promotes brain maturation in newborn preterm pigs. The results provide further support for IGF-1 supplementation therapy in the early postnatal period in preterm infants.