In our experiments on rats we performed visualization of brain clearing from substances injected into the brain parenchyma using optical coherent tomography and fluorescence microscopy. Our results uncovered that the meningeal lymphatic system play an important role in the brain clearing processes, where the deep cervical lymph node is the first anatomical station of cerebral fluid exist from the brain. These data shed light on the novel mechanisms underlying drainage and clearing function of the brain.
This review highlights two opposing concepts of lymphatics and glymphatics, which are used to explain the drainage and cleansing functions of the brain. "Stumbling blocks" in two concepts and ways of compromise between them are discussed.
Here in ex vivo (confocal imaging) and in vivo (optical coherent tomography) experiments on adult mice, we clearly demonstrate that the meningeal lymphatic drainage is an important mechanism for the brain clearing that might be also pathway for the brain clearing from metabolites and waste products that requests further detailed studies. Photodynamic effects stimulate the meningeal/cervical drainage opening new ideas for development of novel methods of activation of brain clearing that might be progressive strategies in therapy of neurovegetative diseases.
Stroke and traumatic brain injury are often associated with formation of brain edema, which is a potentially fatal pathological state provoking extensive accumulation of fluid in the brain tissues resulting in elevation of intracranial pressure and leading to impaired nerve function. There is only symptomatic anti-edema therapy is currently available. Therefore, the development of novel strategies to remove edema fluid is required. The brain edema is classified as vasogenic or cytotoxic edema, which associated with excess accumulation of fluid (edema) around capillaries resulting from disruption of the blood-brain barrier (BBB) or intracellular spaces (cell swelling) of the brain, respectively. In this brief review, we discuss possible mechanisms underlying brain edema formation and new strategies in development of novel of anti-edema drugs.
Here we present preliminary experimental data suggesting about involvement of the meningeal and cervical lymphatics in neurorehabilitation. Using model of hemorrhagic stroke, immunohistochemical analysis and atomic absorption spectroscopy, we clearly demonstrate the lymphatic clearance from the blood after stroke via the meningeal lymphatic vessels with further accumulation of hemosiderin and iron (products of disaggregated hemoglobin) in the deep cervical node (dcLN). The optical coherent tomography (OCT) was used for in vivo monitoring of accumulation of gold nanorods (92 nm in diameter) in the dcLN after their injection into the cisterna magna with the aim of mimicking of the brain clearance from of blood. The both ex vivo and in vivo data show the lymphatic clearance from subjects (the blood/GNRs) injected into the subarachnoid space that might be an important mechanism of neurorehabilitation after the intracranial hemorrhages.