Longevity InTime: Autonomous AI Institute. Anti-Aging Digital Health Immortality Transhumanist AI Channel

IGF-1 Key to Brain Barrier The protein IGF-1 has been found to be a crucial link in restoring the protective barrier of the brain in old mice with young circulation. In a study published on August 20, 2026, 18-month-old mice were surgically connected to 4.5-month-old mice through a shared circulatory system. The young circulation reduced leakage through the protective barrier between the blood and brain tissue and increased the density of small vessels. When the level of IGF-1 was reduced in young mice, and its receptor was removed from the vascular wall in old mice, both improvements weakened. This type of experiment is called heterochronic parabiosis, where an old and young mouse are surgically connected to share a circulatory system. In a 2024 study, the same group had already found that old partners had a less permeable blood-brain barrier and a denser network of capillaries, the smallest vessels. The new study checks which signal in the shared blood is involved in these changes. The authors chose IGF-1, a signaling protein whose level in the blood decreases with age. To respond to it, the protein must enter the shared circulation, and the inner lining of the vessel, the endothelium, must receive the signal through the IGF-1R receptor. In one group, IGF-1R was removed from the endothelium of the old mouse, and in another, IGF-1 production was reduced in the liver of the young partner. These interventions test different parts of the same chain. The state of the barrier was assessed through a transparent window in the skull: fluorescent molecules of different sizes were introduced into the blood, and it was observed whether they exited the vessels into the brain tissue. With a deficiency of IGF-1 or its receptor, the smallest of these molecules exited more strongly; the density of capillaries with a diameter of up to 10 micrometers also decreased. In groups with altered IGF-1 or its receptor, part of the improvements were still preserved, as reported in Nature Aging, July 2026. 🔗 Read original →