Aligning Animal Models of Clinical Germinal Matrix Hemorrhage, From Basic Correlation to Therapeutic Approach.

BACKGROUND: Germinal matrix hemorrhage is a leading cause of mortality and morbidity from prematurity. This brain region is vulnerable to bleeding and re-bleeding within the first 72 hours of preterm life. Cerebroventricular expansion of blood products contributes to the mechanisms of brain injury. Consequences include lifelong hydrocephalus, cerebral palsy, and intellectual disability. Unfortunately little is known about the therapeutic needs of this patient population. OBJECTIVES: This review discusses the mechanisms of germinal matrix hemorrhage, the animal models utilized, and the potential therapeutic targets. CONCLUSION: Potential therapeutic approaches identified in pre-clinical investigations include corticosteroid therapy, iron chelator administration, and transforming growth factor-ß pathway modulation, which all warrant further investigation. Thus, effective preclinical modeling is essential for elucidating and evaluating novel therapeutic approaches, ahead of clinical consideration.

Intranasal Osteopontin for Rodent Germinal Matrix Hemorrhage.

Germinal matrix hemorrhage (GMH) is the most common and devastating neurological problem of premature infants. Current treatment is largely ineffective and GMH has been nonpreventable. Osteopontin (OPN) is an endogenous protein that has been shown to be neuroprotective, however, it has not been tested in GMH. P7 neonatal rats were subjected to stereotactic ganglionic eminence collagenase infusion. Groups were as follows: (1) sham, (2) GMH + vehicle, (3) GMH + intranasal OPN. Seventy-two hours later, the animals were evaluated using righting reflex, blood-brain barrier (BBB) permeability by Evans blue dye leakage, brain water content, and hemoglobin assay. Intranasal OPN improved outcomes after GMH by attenuation of brain swelling, BBB function, re-bleeding, and neurological outcomes. OPN may play an important role in enhancing neuroprotective brain signaling following GMH. These observed effects may offer novel possibilities for therapy in this patient population.

Osteopontin-Rac1 on Blood-Brain Barrier Stability Following Rodent Neonatal Hypoxia-Ischemia.

Osteopontin (OPN) is a neuroprotective molecule that is upregulated following rodent neonatal hypoxic-ischemic (nHI) brain injury. Because Rac1 is a regulator of blood-brain barrier (BBB) stability, we hypothesized a role for this in OPN signaling. nHI was induced by unilateral ligation of the right carotid artery followed by hypoxia (8 % oxygen for 2 h) in P10 Sprague-Dawley rat pups. Intranasal (iN) OPN was administered at 1 h post-nHI. Groups consisted of: (1) Sham, (2) Vehicle, (3) OPN, and (4) OPN + Rac1 inhibitor (NSC23766). Evans blue dye extravasation (BBB permeability) was quantified 24 h post-nHI, and brain edema at 48 h. Increased BBB permeability and brain edema following nHI was ameliorated in the OPN treatment group. However, those rat pups receiving OPN co-treatment with the Rac1 inhibitor experienced no improvement compared with vehicle. OPN protects the BBB following nHI, and this was reversed by Rac1 inhibitor (NSC23766).