Expression of Somatostatin Receptors 1 and 2 in Human Choroid Plexus and Arachnoid Granulations

Abstract

To investigate the localization of somatostatin receptor types 1 and 2 in human choroid plexus (CP) and arachnoid granulations (AGs) by immunohistochemistry. Methods: A prospective study was performed in an institutional setting. Immunohistochemistry was performed on 15 samples of CP and 12 samples of AGs from 15 patients who died with no signs or symptoms of intracranial disease (age range, 52-81 years). The CP samples were dissected from the lateral ventricles and AG samples were dissected from the superior sagittal sinus. Results: We demonstrated the presence of both somatostatin receptor types 1 and 2 in all samples of normal human CP and AGs. Conclusions: Analogous to their demonstration and to their function in kidney and ocular tissues, these receptors may be involved in the processes of cerebrospinal fluid production and absorption, and may play a role in the increased intracranial pressure of idiopathic intracranial hypertension. Clinical Relevance: Somatostatin analogues have been used to treat idiopathic intracranial hypertension, a disorder of cerebrospinal fluid homeostasis. Data are scarce regarding the cell-specific distribution of somatostatin receptors in normal human CP and AGs, the sites of cerebrospinal fluid production and egress.

Structural MRI Biomarkers of Intracranial Pressure in IIH: Linking Optic Nerve Sheath, Pituitary Morphology, and Hormonal Changes

“…GH treatment has been associated with secondary IIH [33], while octreotide, a somatostatin analogue, has improved IIH symptoms [34]. GH/IGF-1 and somatostatin receptor expression in choroid plexus and arachnoid granulations suggest direct endocrine modulation of CSF dynamics [17,35].…”

Structural MRI Biomarkers of Intracranial Pressure in IIH: Linking Optic Nerve Sheath, Pituitary Morphology, and Hormonal Changes

“…GH treatment has been associated with secondary IIH [33], while octreotide, a somatostatin analogue, has improved IIH symptoms [34]. GH/IGF-1 and somatostatin receptor expression in choroid plexus and arachnoid granulations suggest direct endocrine modulation of CSF dynamics [17,35].…”

Topiramate is more effective than acetazolamide at lowering intracranial pressure

“…Recently, two uncontrolled studies conducted in IIH patients have shown an improvement in IIH symptoms with octreotide treatment (36,37). As somatostatin receptors are highly expressed in the arachnoid villi and choroid plexus, it was proposed that octreotide could directly influence CSF dynamics and thus ICP (38). Our studies do not support this hypothesis, instead showing that subcutaneous administration of octreotide does not alter ICP.…”

Can Elevated IGF ‐1 Levels Among Patients With E hlers– D anlos Syndrome Cause Idiopathic Intracranial Hypertension?

“…Whatever the exact mechanism may be, studies have demonstrated the role of elevated levels of GH and IGF‐1 in raising intracranial pressure . Specifically, there has been evidence suggesting that IGF‐1 receptors present at the level of the choroid plexus – the site of CSF production – are excessively stimulated in high GH‐IGF‐1 states (as seen in cases of acromegaly or HMS) leading to excess CSF production and thus increased intracranial pressure.…”

Structural MRI Biomarkers of Intracranial Pressure in IIH: Linking Optic Nerve Sheath, Pituitary Morphology, and Hormonal Changes

“…GH treatment has been associated with secondary IIH [33], while octreotide, a somatostatin analogue, has improved IIH symptoms [34]. GH/IGF-1 and somatostatin receptor expression in choroid plexus and arachnoid granulations suggest direct endocrine modulation of CSF dynamics [17,35].…”

Topiramate is more effective than acetazolamide at lowering intracranial pressure

“…Recently, two uncontrolled studies conducted in IIH patients have shown an improvement in IIH symptoms with octreotide treatment (36,37). As somatostatin receptors are highly expressed in the arachnoid villi and choroid plexus, it was proposed that octreotide could directly influence CSF dynamics and thus ICP (38). Our studies do not support this hypothesis, instead showing that subcutaneous administration of octreotide does not alter ICP.…”

Can Elevated IGF ‐1 Levels Among Patients With E hlers– D anlos Syndrome Cause Idiopathic Intracranial Hypertension?

“…Whatever the exact mechanism may be, studies have demonstrated the role of elevated levels of GH and IGF‐1 in raising intracranial pressure . Specifically, there has been evidence suggesting that IGF‐1 receptors present at the level of the choroid plexus – the site of CSF production – are excessively stimulated in high GH‐IGF‐1 states (as seen in cases of acromegaly or HMS) leading to excess CSF production and thus increased intracranial pressure.…”

Structural MRI Biomarkers of Intracranial Pressure in IIH: Linking Optic Nerve Sheath, Pituitary Morphology, and Hormonal Changes

“…GH treatment has been associated with secondary IIH [33], while octreotide, a somatostatin analogue, has improved IIH symptoms [34]. GH/IGF-1 and somatostatin receptor expression in choroid plexus and arachnoid granulations suggest direct endocrine modulation of CSF dynamics [17,35].…”

Topiramate is more effective than acetazolamide at lowering intracranial pressure

“…Recently, two uncontrolled studies conducted in IIH patients have shown an improvement in IIH symptoms with octreotide treatment (36,37). As somatostatin receptors are highly expressed in the arachnoid villi and choroid plexus, it was proposed that octreotide could directly influence CSF dynamics and thus ICP (38). Our studies do not support this hypothesis, instead showing that subcutaneous administration of octreotide does not alter ICP.…”

Can Elevated IGF ‐1 Levels Among Patients With E hlers– D anlos Syndrome Cause Idiopathic Intracranial Hypertension?

“…Whatever the exact mechanism may be, studies have demonstrated the role of elevated levels of GH and IGF‐1 in raising intracranial pressure . Specifically, there has been evidence suggesting that IGF‐1 receptors present at the level of the choroid plexus – the site of CSF production – are excessively stimulated in high GH‐IGF‐1 states (as seen in cases of acromegaly or HMS) leading to excess CSF production and thus increased intracranial pressure.…”