Antiinfective agents affecting cognition: a review

Impact of Plasmodium vivax malaria on executive and cognitive functions in elderlies in the Brazilian Amazon

The exact path leading to cognitive impairment that goes beyond malaria is unclear, but it appears to be the result of interactive factors. Time of exposure to disease and recurrences are potentially major determinant variables. Cognitive impairment is described mainly in children, rarely in adults. The disease in high endemic areas usually does not affect elderlies, because of acquired immunity over time. However, this population is relatively more frequently sick in lower endemic areas, such as in the Amazon. This study assessed the effect of Plasmodium vivax malaria on the executive and cognitive functions of elderlies, in the Brazilian Amazon. A cohort study was conducted to evaluate executive and cognitive functions one week (T0), two months (T2) and eight months (T8) after the malaria episode. Mini-Mental State Examination (MMSE), Beck Depression Inventory II (BDI-II), Clock Drawing Test (CDT), Wechsler adult intelligence scale (WAIS-III), and Wisconsin Card Sorting Test (WCST) were used to assess executive and cognitive functions. One hundred-forty elderlies were enrolled (70 with P. vivax malaria and 70 without malaria). P. vivax malaria was associated with impairment of the executive and cognitive functions in elderlies for up to 8 months after acute P. vivax malaria. Prior history of malaria, recurrences and higher parasitemia were independently associated with various surrogates of executive and cognitive impairment. With the increase in life expectancy, elderlies living in malaria endemic areas will deserve more attention from health authorities, to guarantee improvement of their quality of life in the tropics.

β-lactam antibiotics to tame down molecular pathways of Alzheimer's disease

Alzheimer's disease is a multifactorial disorder characterized by extracellular accumulation of amyloid-β (Aβ) and intracellular accumulations of neurofibrillary tangles. Numerous drug targets have been explored for therapeutic efficacy but failed to deliver successful treatments clinically. However, over the years our understanding of the disease pathophysiology increased significantly. Many of the novel targets which can cure or modify disease pathology are being explored preclinically as well as clinically. On contrarily, the drug discovery and development process is lengthy and the cost involved makes it difficult for faster translation of therapeutic outcomes. Therefore, repurposing existing drugs for a new therapeutic indication is considered a better approach and helps in the fast translation of therapeutic information. The existing drugs have well-proven records on their safety, pharmacokinetics, etc. In recent years, beta (β)-lactam antibiotics have been repurposed for the management of neurodegenerative pathologies. Here in the current review, we have explored β-lactam antibiotics, their target sites, molecular mechanisms, and their therapeutic potential in Alzheimer's disease.

Gastrointestinal inflammation by gut microbiota disturbance induces memory impairment in mice

In this study, we tested our hypothesis regarding mechanistic cross-talk between gastrointestinal inflammation and memory loss in a mouse model. Intrarectal injection of the colitis inducer 2,4,6-trinitrobenzenesulfonic acid (TNBS) in mice caused colitis via activation of nuclear factor (NF)-κB and increase in membrane permeability. TNBS treatment increased fecal and blood levels of lipopolysaccharide (LPS) and the number of Enterobacteriaceae, particularly Escherichia coli (EC), in the gut microbiota composition, but significantly reduced the number of Lactobacillus johnsonii (LJ). Indeed, we observed that the mice treated with TNBS displayed impaired memory, as assessed using the Y-maze and passive avoidance tasks. Furthermore, treatment with EC, which was isolated from the feces of mice with TNBS-induced colitis, caused memory impairment and colitis, and increased the absorption of orally administered LPS into the blood. Treatment with TNBS or EC induced NF-κB activation and tumor necrosis factor-α expression in the hippocampus of mice, as well as suppressed brain-derived neurotrophic factor expression. However, treatment with LJ restored the disturbed gut microbiota composition, lowered gut microbiota, and blood LPS levels, and attenuated both TNBS- and EC-induced memory impairment and colitis. These results suggest that the gut microbiota disturbance by extrinsic stresses can cause gastrointestinal inflammation, resulting in memory impairment.