Increased MMP-9 and TIMP-1 in mouse neonatal brain and plasma and in human neonatal plasma after hypoxia–ischemia: a potential marker of neonatal encephalopathy

Abstract

ArticlesTranslational Investigation nature publishing group INTRODUCTION:To implement neuroprotective strategies in newborns, sensitive and specific biomarkers are needed for identifying those who are at risk for brain damage. We evaluated the effectiveness of matrix metalloproteinases (MMPs) and their naturally occurring tissue inhibitors of metalloproteinases (TIMPs) in predicting neonatal encephalopathy (Ne) damage in newborns. RESULTS: Plasma MMP-9 and TIMP-1 levels were upregulated as early as 1 h after the hI insult but not did not show such elevations after other types of injury (ibotenate-induced excitotoxicity, hypoxia, lipopolysaccharide-induced inflammation), and brain levels reflected this increase soon thereafter. We confirmed these results by carrying out plasma MMP-9 and TIMP-1 measurements in human newborns with Ne. In these infants, protein levels of MMP-9 and TIMP-1 were found to be elevated during a short window up to 6 h after birth. DISCUSSION: This feature is particularly useful in identifying newborns in need of neuroprotection. a second peak observed 72 h after birth is possibly related to the second phase of energy failure after a hI insult. Our data, although preliminary, support the use of MMP-9 and TIMP-1 as early biomarkers for the presence and extent of perinatal brain injury in human term newborns. METHODS: We first used a mouse model of neonatal hI injury to explore mechanistic aspects such as the time course of these markers after the hypoxia-ischemia event, and the correlation between the levels of these candidate markers in brain and plasma.T he major perinatal brain lesions associated with cerebral palsy and cognitive impairment are periventricular white matter damage and cortical-subcortical lesions, observed mainly in preterm and term infants, respectively (1,2). A crucial step for the implementation of neuroprotective therapies is the rapid detection of neonates at risk. Despite this urgent need, no appropriate and easily detectable biomarkers for perinatal injury are currently available.Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are involved in multiple processes during development and in adulthood (3-5), including perinatal hypoxia-ischemia (HI) and white matter damage in human neonates. Recent studies in adult MMP-9 knockout mice have demonstrated the key role played by this metalloproteinase in the pathophysiology of traumatic and hypoxic-ischemic (HI) brain injury (6). Concordantly, MMP-9 has been shown to have deleterious effects in the immature brain after HI injury (7). Several of these studies demonstrated a significant increase in MMP-9 expression in the central nervous system within the first 24 h after the insult. MMP-9 also has long-term beneficial effects on neurovascular remodeling and behavioral recovery after stroke in adult rats (8,9). In the adult rat central nervous system, elevated TIMP-1 expression levels may play a neuroprotective role after kainate-induced excitotoxic seizures (10), and gene transfer of TIMP-...

Inhibition of MMP-9 Activity following Hypoxic Ischemia in the Developing Brain Using a Highly Specific Inhibitor

“…This spatiotemporal pattern of MMP-9 upregulation strongly correlated with the period of highest delayed neuronal death in the correspondent animal model [10]. Recent studies by Bednarek et al [11] using a mouse model of neonatal HI injury have demonstrated a significant increase in the levels of neocortical gelatinolytic activity and protein levels of MMP-9 but not MMP-2 24 h and 3 days after hypoxic ischaemia. Given these findings, we therefore conclude that MMP-9 may be a useful target for rescue therapies in the injured developing brain.…”

Epigenetic modifications associated with aortic remodeling in hyperhomocysteinemia.

“…The increase in TIMP1 appears to be compensatory to increased MMP9. Consistent with our findings, increased MMP9 and TIMP1 occurs in pathologies such as neonatal encephalopathy [166] and aortic aneurysm [167]. Our results demonstrated that Aza treatment reduces collagen deposition and also decreases MMP9 and TIMP1 expression in HHcy.…”

Ischemic-Reperfusion Injury Increases Matrix Metalloproteinases and Tissue Metalloproteinase Inhibitors in Fetal Sheep Brain

“…We visualized the signals using enhanced chemiluminescence (ECL Prime; GE Healthcare Bio-Sciences, Pittsburgh, PA, USA) before exposure to autoradiographic film (Phenix, Candler, NC, USA). We detected pro-MMP-2, cleaved-MMP-2, MMP-8, MMP-13, TIMP-1, TIMP-2, TIMP-3, TIMP-4, β-actin, and vinculin bands at 72,64,53,54,26,24,26,25,42, and 117 kDa, respectively. Omission of the primary antibodies eliminated the chemiluminescent signals, thereby establishing the specificity of the primary antibodies to detect the specific protein bands.…”

“…Consequently, it is important to understand the effects of different durations of reperfusion after ischemia on brain injury to determine therapeutic strategies that could attenuate the untoward effects of perinatal brain damage [24]. Accumulating evidence suggests that there is an association between BBB dysfunction and changes in MMPs and TIMPs after hypoxic-ischemic brain injury in the neonatal rodent brain [13,25,26]. However, the expression profiles of MMPs and TIMPs have not previously been examined after ischemia in the brain of a large mammalian fetus.…”