{"entity":{"id":"idea-bio2-blood-csf-barrier-model","kind":"idea","name":"Build a human model of the barrier that guards the brain fluid","aka":[],"tldr":"Drugs that reach brain tissue may still fail to reach the fluid where cancer spreads along the linings. A lab model of that second barrier would let us screen for drugs that cross it.","summary":"Leptomeningeal disease is governed by the blood-cerebrospinal fluid barrier at the choroid plexus, which differs from the blood-brain barrier in transporters and tight junction composition. Stem-cell-derived choroid plexus organoids that produce cerebrospinal fluid-like secretion have been reported, giving a human in vitro system for screening cerebrospinal fluid penetration and for studying how tumour cells survive in that nutrient-poor compartment.","asOf":"2026-09-08","links":[{"label":"Bottleneck evidence (The brain: barrier and sanctuary): Stupp et al., Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma (NEJM 2005)","url":"https://doi.org/10.1056/NEJMoa043330"}],"tags":[],"related":[],"cancers":["breast-her2-positive","nsclc","melanoma"],"sections":[],"technologies":["organoids"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["blood-brain-barrier"],"trials":[],"people":[],"bottlenecks":["b-brain-delivery","b-preclinical-models"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"Choroid plexus organoid permeability ranks drugs concordantly with measured human cerebrospinal fluid-to-plasma ratios, making it a usable screening assay for leptomeningeal indications.","rationale":"Leptomeningeal metastasis is rarely survived beyond a few months and is increasingly common as systemic control improves, yet drug selection for it is guesswork. A quantitative human assay for the correct barrier is a prerequisite for rational selection.","test":"Benchmark organoid permeability against 20 drugs with published human cerebrospinal fluid-to-plasma ratios; report rank correlation and cost per compound.","maturity":"preclinical-evidence","actor":"engineering","cost":"medium","horizonYears":6},"route":"/ideas/idea-bio2-blood-csf-barrier-model/","neighbours":{"cancer":[{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"},{"id":"melanoma","kind":"cancer","name":"Melanoma","route":"/cancers/melanoma/"},{"id":"nsclc","kind":"cancer","name":"Non-small-cell lung cancer","route":"/cancers/nsclc/"}],"technology":[{"id":"organoids","kind":"technology","name":"Patient-derived organoids","route":"/technologies/organoids/"}],"term":[{"id":"blood-brain-barrier","kind":"term","name":"Blood-brain barrier (BBB)","route":"/terms/blood-brain-barrier/"}],"bottleneck":[{"id":"b-preclinical-models","kind":"bottleneck","name":"Lab models that fail to predict what happens in patients","route":"/bottlenecks/b-preclinical-models/"},{"id":"b-brain-delivery","kind":"bottleneck","name":"The brain: barrier and sanctuary","route":"/bottlenecks/b-brain-delivery/"}]}}