Hippocampus under pressure: molecular mechanisms of cognitive impairment in shr rats

In clinical studies and in animal experiments, data have been obtained indicating the association of chronic hypertension with the development of cognitive impairment. The review examines structural and biochemical changes in the hippocampus of SHR rats with genetic hypertension, which are used as a model of essential hypertension, as well as vascular dementia. The dysfunction of the hypothalamic-pituitary-adrenocortical system, observed in SHR rats at an early age, may, along with the development of hypertension, be a key factor in the damage to the hippocampus at the structural and molecular levels. Global changes at the body level (hypertension, neurohumoral dysfunction) are associated with the development of vascular pathology and destruction of the blood-brain barrier. Changes in multiple biochemical glucocorticoid-dependent processes in the hippocampus (dysfunction of steroid hormone receptors, disorders of neurotransmitter systems, BDNF deficiency, oxidative stress, neuroinflammation) are accompanied by structural changes including cellular processes of neuroinflammation (microgliosis, astrogliosis), disorders of neurogenesis in the subgranular neurogenic niche, neurodegenerative processes at the level of synapses, axons and dendrites up to neuronal cell death. The consequence of this is dysfunction of the hippocampus, a key structure of the limbic system necessary for the realization of cognitive functions. Summarizing of the available results at various levels, from the level of the organism and the structure of the brain (hippocampus) to the molecular one, allows us to confirm the translational validity of SHR rats for modeling the mechanisms of vascular dementia.