Isolation of Cerebral Capillaries from Human Brain: An Optimized Method to Extract Cerebral Capillaries from Human Brain Tissue

Cerebral capillaries are a vital component of the blood-brain barrier - a semi-permeable barrier that allows selective movement of solutes between the blood and brain. To isolate cerebral capillaries, begin with fresh human brain tissue. Remove the meninges and chop off the white matter.

Mince the brain tissue into smaller fragments. Transfer the fragments to a homogenizer containing a suitable buffer and homogenize. Homogenization disintegrates the tissues, releasing capillaries and tissue debris into the solution.

Transfer the homogenate to a fresh tube and add an optimum volume of a suitable density gradient medium. Centrifuge the solution to pellet the capillaries. Too much or too little density gradient medium results in low capillary yield. Remove the supernatant.

Resuspend the pellet in bovine serum albumin or BSA-supplemented buffer. BSA stabilizes digestive enzymes and maintains the structural integrity of capillaries. Next, filter the solution with an appropriate filter to remove large vessels and tissue debris.

Then, pass the filtrate through a smaller mesh filter. This filter retains the cerebral capillaries and allows smaller debris and red blood cells to pass through. Subsequently, flip the filter and wash off the capillaries in a fresh tube with  BSA-supplemented buffer.

Centrifuge the solution and remove the supernatant. Resuspend the pure capillaries in buffer and store them for further use.