Cytoprotective role of haptoglobin in brain after experimental intracerebral hemorrhage

Xiurong Zhao1, Shen Song, Guanghua Sun

  • 1Stroke Program-Department of Neurology, University of Texas Health Science Center, Medical School at Houston, Houston, TX 77030, USA.

After intracerebral hemorrhage (ICH), hemoglobin (Hb) that is released from erythrocytes within the brain hematoma is highly cytotoxic and leads to severe brain edema and direct neuronal damage. Therefore, neutralization of Hb could represent an important target for reducing the secondary injury after ICH. Haptoglobin (Hp), an endogenous Hb-binding protein in blood plasma, is found in this study to be upregulated in the hematoma-affected brain after ICH. Both in vivo and in vitro studies indicate that Hp upregulation is primarily mediated by oligodendrocytes. Hp acts as a secretory protein capable of neutralizing the cell-free Hb. We also found in an "ICH-like" injury that Hp-KO mice show the most severe brain injury and neurological deficits, whereas Hp-Tg mice are the most resistant to ICH injury, suggesting that a higher Hp level is associated with the increased resistance of animals to hemolytic product-mediated brain injury after ICH. We conclude that brain-derived Hp plays a cytoprotective role after ICH, and Hp may represent a new potential therapeutic target for management of ICH.

Related Concept Videos

Hemorrhagic Stroke ll: Pathophysiology01:29

Hemorrhagic Stroke ll: Pathophysiology

A hemorrhagic stroke develops when a cerebral blood vessel ruptures, allowing blood to escape into the surrounding brain tissue, as in intracerebral hemorrhage (ICH), or into the subarachnoid space, as in subarachnoid hemorrhage (SAH). Because the skull is a rigid compartment, the sudden presence of extravascular blood rapidly increases intracranial pressure and compresses adjacent neural structures, leading to immediate tissue injury and impaired cerebral perfusion.Mass Effect and Primary...
Cerebral Edema ll: Pathophysiology01:22

Cerebral Edema ll: Pathophysiology

Vasogenic edema is a major form of cerebral edema characterized by abnormal accumulation of fluid in the brain’s extracellular space due to disruption of the blood–brain barrier (BBB). The BBB is a specialized structure composed of endothelial cells connected by tight junctions, supported by astrocytic endfeet and a basement membrane. Under normal conditions, it tightly regulates the movement of ions, proteins, and solutes between the bloodstream and brain parenchyma. When this barrier loses...
Cytotoxic Edema: Pathophysiology01:21

Cytotoxic Edema: Pathophysiology

Cytotoxic edema is a form of cerebral edema characterized by intracellular swelling of neurons, astrocytes, and other glial cells. It develops when the mechanisms responsible for maintaining ionic gradients across the cell membrane become impaired. Under normal physiological conditions, the sodium–potassium ATPase actively transports sodium ions out of the cell and potassium ions into the cell, preserving osmotic balance and enabling electrical signaling. This pump requires a continuous supply...
Hemorrhagic Stroke l: Introduction01:17

Hemorrhagic Stroke l: Introduction

A hemorrhagic stroke is an acute neurological event that occurs when a weakened cerebral blood vessel ruptures, allowing blood to accumulate within or around the brain. The sudden release of blood forms a focal hematoma that increases intracranial pressure, displaces neural tissue, and can obstruct cerebrospinal fluid pathways. These effects may be compounded by intraventricular extension of the hemorrhage, cerebral edema, or compression of adjacent structures, all of which contribute to...