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Impaired Cerebellar Maturation, Growth Restriction, and Circulating Insulin-Like Growth Factor 1 in Preterm Rabbit Pups

Sveinsdóttir, Kristbjörg LU ; Länsberg, John Kalle LU ; Sveinsdóttir, Snjólaug LU ; Garwicz, Martin LU ; Ohlsson, L.; Hellström, Ann LU ; Smith, Lois; Gram, Magnus LU and Ley, David LU (2017) In Developmental Neuroscience
Abstract

Cerebellar growth is impeded following very preterm birth in human infants and the observed reduction in cerebellar volume is associated with neurodevelopmental impairment. Decreased levels of circulating insulin-like growth factor 1 (IGF-1) are associated with decreased cerebellar volume. The relationship between preterm birth, circulating IGF-1, and key cell populations supporting cerebellar proliferation is unknown. The aim of this study was to evaluate the effect of preterm birth on postnatal growth, circulating IGF-1, and cerebellar maturation in a preterm rabbit pup model. Preterm rabbit pups (PT) were delivered by cesarean section at day 29 of gestation, cared for in closed incubators with humidified air, and gavage fed with... (More)

Cerebellar growth is impeded following very preterm birth in human infants and the observed reduction in cerebellar volume is associated with neurodevelopmental impairment. Decreased levels of circulating insulin-like growth factor 1 (IGF-1) are associated with decreased cerebellar volume. The relationship between preterm birth, circulating IGF-1, and key cell populations supporting cerebellar proliferation is unknown. The aim of this study was to evaluate the effect of preterm birth on postnatal growth, circulating IGF-1, and cerebellar maturation in a preterm rabbit pup model. Preterm rabbit pups (PT) were delivered by cesarean section at day 29 of gestation, cared for in closed incubators with humidified air, and gavage fed with formula. Control term pups (T) delivered by spontaneous vaginal delivery at day 32 of gestation were housed and fed by their lactating doe. In vivo perfusion-fixation for immunohistochemical evaluation of cerebellar proliferation, cell maturation, and apoptosis was performed at repeated time points in PT and T pups. Results show that the mean weight of the pups and circulating IGF-1 protein levels were lower in the PT group at all time points (p < 0.05) than in the T group. Postnatal weight development correlated with circulating IGF-1 (r2 = 0.89) independently of gestational age at birth and postnatal age. The proliferative (Ki-67-positive) portion of the external granular layer (EGL) was decreased in the PT group at postnatal day 2 (P2) compared to in the T group (p = 0.01). Purkinje cells exhibited decreased calbindin staining at P0 (p = 0.003), P2 (p = 0.004), and P5 (p = 0.04) in the PT group compared to in the T group. Staining for sonic hedgehog was positive in neuronal EGL progenitors and Purkinje cells at early time points but was restricted to a well-defined Purkinje cell monolayer at later time points. Preterm birth in rabbit pups is associated with lower circulating levels of IGF-1, decreased postnatal growth, and decreased cerebellar EGL proliferation and Purkinje cell maturation. The preterm rabbit pup model exhibits important characteristics of human preterm birth, and may thus be suitable for the evaluation of interventions aiming to modify growth and cerebellar development in the preterm population.

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organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Cerebellum, Insulin-like growth factor 1, Preterm birth, Purkinje cells, Sonic hedgehog protein
in
Developmental Neuroscience
publisher
Karger
external identifiers
  • scopus:85030659635
  • wos:000416852800004
ISSN
0378-5866
DOI
10.1159/000480428
language
English
LU publication?
yes
id
97aeacbb-d711-48ce-baa9-377cbe35fc72
date added to LUP
2017-10-16 11:01:58
date last changed
2018-01-16 13:23:06
@article{97aeacbb-d711-48ce-baa9-377cbe35fc72,
  abstract     = {<p>Cerebellar growth is impeded following very preterm birth in human infants and the observed reduction in cerebellar volume is associated with neurodevelopmental impairment. Decreased levels of circulating insulin-like growth factor 1 (IGF-1) are associated with decreased cerebellar volume. The relationship between preterm birth, circulating IGF-1, and key cell populations supporting cerebellar proliferation is unknown. The aim of this study was to evaluate the effect of preterm birth on postnatal growth, circulating IGF-1, and cerebellar maturation in a preterm rabbit pup model. Preterm rabbit pups (PT) were delivered by cesarean section at day 29 of gestation, cared for in closed incubators with humidified air, and gavage fed with formula. Control term pups (T) delivered by spontaneous vaginal delivery at day 32 of gestation were housed and fed by their lactating doe. In vivo perfusion-fixation for immunohistochemical evaluation of cerebellar proliferation, cell maturation, and apoptosis was performed at repeated time points in PT and T pups. Results show that the mean weight of the pups and circulating IGF-1 protein levels were lower in the PT group at all time points (p &lt; 0.05) than in the T group. Postnatal weight development correlated with circulating IGF-1 (r<sup>2</sup> = 0.89) independently of gestational age at birth and postnatal age. The proliferative (Ki-67-positive) portion of the external granular layer (EGL) was decreased in the PT group at postnatal day 2 (P2) compared to in the T group (p = 0.01). Purkinje cells exhibited decreased calbindin staining at P0 (p = 0.003), P2 (p = 0.004), and P5 (p = 0.04) in the PT group compared to in the T group. Staining for sonic hedgehog was positive in neuronal EGL progenitors and Purkinje cells at early time points but was restricted to a well-defined Purkinje cell monolayer at later time points. Preterm birth in rabbit pups is associated with lower circulating levels of IGF-1, decreased postnatal growth, and decreased cerebellar EGL proliferation and Purkinje cell maturation. The preterm rabbit pup model exhibits important characteristics of human preterm birth, and may thus be suitable for the evaluation of interventions aiming to modify growth and cerebellar development in the preterm population.</p>},
  author       = {Sveinsdóttir, Kristbjörg and Länsberg, John Kalle and Sveinsdóttir, Snjólaug and Garwicz, Martin and Ohlsson, L. and Hellström, Ann and Smith, Lois and Gram, Magnus and Ley, David},
  issn         = {0378-5866},
  keyword      = {Cerebellum,Insulin-like growth factor 1,Preterm birth,Purkinje cells,Sonic hedgehog protein},
  language     = {eng},
  month        = {10},
  publisher    = {Karger},
  series       = {Developmental Neuroscience},
  title        = {Impaired Cerebellar Maturation, Growth Restriction, and Circulating Insulin-Like Growth Factor 1 in Preterm Rabbit Pups},
  url          = {http://dx.doi.org/10.1159/000480428},
  year         = {2017},
}