From Gut Microbiota to Brain Waves: The Potential of the Microbiome and EEG as Biomarkers for Cognitive Impairment.

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder and a leading cause of dementia. Aging is a significant risk factor for AD, emphasizing the importance of early detection since symptoms cannot be reversed once the advanced stage is reached. Currently, there is no established method for early AD diagnosis. However, emerging evidence suggests that the microbiome has an impact on cognitive function. The gut microbiome and the brain communicate bidirectionally through the gut-brain axis, with systemic inflammation identified as a key connection that may contribute to AD. Gut dysbiosis is more prevalent in individuals with AD compared to their cognitively healthy counterparts, leading to increased gut permeability and subsequent systemic inflammation, potentially causing neuroinflammation. Detecting brain activity traditionally involves invasive and expensive methods, but electroencephalography (EEG) poses as a non-invasive alternative. EEG measures brain activity and multiple studies indicate distinct patterns in individuals with AD. Furthermore, EEG patterns in individuals with mild cognitive impairment differ from those in the advanced stage of AD, suggesting its potential as a method for early indication of AD. This review aims to consolidate existing knowledge on the microbiome and EEG as potential biomarkers for early-stage AD, highlighting the current state of research and suggesting avenues for further investigation.

Evaluation of p53 protein expression in Barrett esophagus.

BACKGROUND: Loss of heterozygosity of p53 along with aneuploidy is deemed to be the early molecular steps in Barrett metaplasia-dysplasia-adenocarcinoma sequence. Objective biomarkers need to be used along with microscopy for risk stratification to predict the progression of Barrett esophagus (BE) to carcinoma. AIM: This study aims to study p53 protein expression in dysplasia and correlate the same with morphology in BE. MATERIALS AND METHODS: A time-bound study was conducted from January 2011 to June 2015. All esophageal biopsies showing histological evidence of columnar epithelium with the presence of goblet cells were included. The cases which showed dysplasia were graded on hematoxylin and eosin stain. Evaluation of p53 immunohistochemistry staining was done on all the cases of BE. Dysplasia was correlated with the expression of p53 using Chi-square value (χ2) and Fischer's exact test wherever appropriate. P < 0.05 was considered to be statistically significant. RESULTS: Of 829 esophageal biopsies received, 119 were endoscopically suspected to be BE, of which 85 cases were confirmed on microscopy. In our study, there were 75 cases negative for dysplasia (88.2%), 8 with low-grade dysplasia (LGD) (9.4%), and two with high-grade dysplasia (HGD) (2.4%). Three cases of BE had associated adenocarcinoma. Immunostaining with p53 done on all the 85 cases showed positive staining in all cases with LGD, one with HGD and two with adenocarcinoma. In the present study, immunostaining with p53 showed 90% sensitivity, 89.3% specificity, positive predictive value of 52.9%, and negative predictive value of 98.5%. CONCLUSION: The technical simplicity, easy availability, and comparatively lower cost enhance the role of p53 as a biomarker in risk stratification for patients with BE.