Cognitive Impairment and Brain and Peripheral Alterations in a Murine Model of Intraventricular Hemorrhage in the Preterm Newborn

Abstract

Germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) remains a serious complication in the preterm newborn. The significant increase of survival rates in extremelye preterm newborns has also contributed to increase the absolute number of patients developing GMH-IVH. However, there are relatively few available animal models to understand the underlying mechanisms and peripheral markers or prognostic tools. In order to further characterize central complications and evolution of GMH-IVH, we injected collagenase intraventricularly to P7 CD1 mice and assessed them in the short (P14) and the long term (P70). Early complications at P14 included ventricle enlargement, increased bleeding, and inflammation. These alterations were maintained at P70, when increased tau phosphorylation and decreased neurogenesis were also observed, resulting in impaired learning and memory in these early adult mice. We additionally analyzed peripheral blood biomarkers in both our mouse model and preterm newborns with GMH-IVH. While MMP9 levels were not significantly altered in mice or newborns, reduced gelsolin levels and increased ubiquitin carboxy-terminal hydrolase L1 and tau levels were detected in GMH-IVH patients at birth. A similar profile was observed in our mouse model after hemorrhage. Interestingly, early changes in gelsolin and carboxy-terminal hydrolase L1 levels significantly correlated with the hemorrhage grade in newborns. Altogether, our data support the utility of this animal model to reproduce the central complications and peripheral changes observed in the clinic, and support the consideration of gelsolin, carboxy-terminal hydrolase L1, and tau as feasible biomarkers to predict the development of GMH-IVH.

Erythropoietin Improves Atrophy, Bleeding and Cognition in the Newborn Intraventricular Hemorrhage

“…MMP9 plasma levels were not significantly affected (P14 [F (5 , 63) = 0.689, p = 0.633]; P70 [F (5 , 63) = 0.953, p = 0.453]) ( Figure 5A). On the other hand, gelsolin levels were reduced after Col lesions at P14, as described (Segado-Arenas et al, 2018), while EPO treatment counterbalanced this situation [F (5 , 60) = 4.372, * * p = 0.002 vs. rest of the groups]. Differences were no longer significant in the long term (P70 [F (5 , 60) = 0.770, p = 0.575]) ( Figure 5B).…”

“…In order to help disentangle the effects of EPO treatment, we have treated with EPO a recently characterized murine model of GM-IVH of the preterm newborn, induced by Col administration (Segado-Arenas et al, 2018). While evident limitations persist, it is noteworthy that this model reproduces morphological, functional and neurodevelopmental alterations of the GM-IVH.…”

“…Germinal matrix-intraventricular hemorrhage was induced to male and female CD1 mice at P7 by intracerebroventricular (icv) infusion of Col VII-S (batch number: SLBG8830V Sigma, St Louis, MO) (Segado-Arenas et al, 2018). Mice were anesthetized with isoflurane and placed in a stereotaxic frame (David-Kopf, California, United States).…”

“…Rotarod (Ugo Basile Srl; Varese, Italia) was used to evaluate motor skills as described (Segado-Arenas et al, 2018). Mice were placed in the cylinder 4 min at 4 rpm for habituation purposes.…”

“…Plasma matrix metalloproteinase 9 (MMP9) and gelsolin levels were measured, as feasible markers of central damage, in the short (P14) and the long (P70) term. We used ELISA kits for MMP9 (R&D System Corp, MN, United States) and gelsolin (Cusabio Biotech Co., Wuhan, Hubei Province, China), following manufacturer's indications as previously described (Segado-Arenas et al, 2018).…”