Graphical An illustrative scheme summarizing the main outcomes in Swiss mice fed high-fat diet (HFD), with their exact time of onset of changes in the hippocampus. An increase in the expression of proinflammatory cytokines, together with the permeability of the blood–brain barrier was detected after 2 days of HFD. Even in the first week of dietary intervention, memory and learning impairment, depressive-like behavior, and synaptic changes were observed at 3, 5, and 7 days, respectively. Later hippocampal alterations (after 4 weeks of HFD consumption) include mitochondrial dysfunction and astrocytic activation.

Here, we critically review the literature on the capacity of organoselenium compounds to mimic selenoproteins (particularly GPx) and discuss some of the bottlenecks in the field.

Background: Evidence has revealed an association between familial hypercholesterolemia and cognitive impairment. In this regard, a connection between cognitive deficits and hippocampal blood-brain barrier (BBB) breakdown was found in low-density lipoprotein receptor knockout mice (LDLr–/–), a mouse model of familial hypercholesterolemia. Objective: Herein we investigated the impact of a hypercholesterolemic diet on cognition and BBB function in C57BL/6 wild-type and LDLr–/–mice. Methods: Animals were fed with normal or high cholesterol diets for 30 days. Thus, wild-type and LDLr–/–mice were submitted to memory paradigms. Additionally, BBB integrity was evaluated in the mice’s prefrontal cortices and hippocampi. Results: A tenfold elevation in plasma cholesterol levels of LDLr–/–mice was observed after a hypercholesterolemic diet, while in wild-type mice, the hypercholesterolemic diet exposure increased plasma cholesterol levels only moderately and did not induce cognitive impairment. LDLr–/–mice presented memory impairment regardless of the diet. We observed BBB disruption as an increased permeability to sodium fluorescein in the prefrontal cortices and hippocampi and a decrease on hippocampal claudin-5 and occludin mRNA levels in both wild-type and LDLr–/–mice treated with a hypercholesterolemic diet. The LDLr–/–mice fed with a regular diet already presented BBB dysfunction. The BBB-increased leakage in the hippocampi of LDLr–/–mice was related to high microvessel content and intense astrogliosis, which did not occur in the control mice. Conclusion: Therefore, LDLr–/–mice seem to be more susceptible to cognitive impairments and BBB damage induced by exposure to a high cholesterol diet. Finally, BBB disruption appears to be a relevant event in hypercholesterolemia-induced brain alterations.