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Research Paper|Volume 17, Issue 2|pp 393—407

Exploring the role of acylated ghrelin and gut microbiome in delineating cognitive health in the elderly

Sudeshna Rout1, Rishikesh Dash2, Varsha Satish2, Giriprasad Venugopal2, Bodepudi Narasimha Rao3, Debapriya Bandhyopadhyay1, Sanjeev Kumar Bhoi4, Balamurugan Ramadass1,2,5
  • 1Department of Biochemistry, All India Institute of Medical Sciences Bhubaneswar, Odisha 751019, India
  • 2Centre of Excellence for Clinical Microbiome and Research (CCMR), All India Institute of Medical Sciences Bhubaneswar, Odisha 751019, India
  • 3Department of Physiology, All India Institute of Medical Sciences Bhubaneswar, Odisha 751019, India
  • 4Department of Neurology, All India Institute of Medical Sciences Bhubaneswar, Odisha 751019, India
  • 5Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5000, Australia
* Equal contribution
Received: September 10, 2024Accepted: January 30, 2025Published: February 7, 2025
https://doi.org/10.18632/aging.206200

Copyright: © 2025 Rout et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Introduction: With increased life expectancy, there is an increase in aging population and prevalence of dementia. Ghrelin is a key regulator of spatial memory and cognition. The gut microbiome may affect the circulating levels of unacylated ghrelin (UAG) and acylated ghrelin (AG). Thus, we explore the potential association of the gut microbiome, AG, and cognitive health in the aging dementia patient.

Methods: 40 dementia patients and 40 controls were recruited. Fecal Microbiome analysis using 16S rRNA sequencing was performed on 18 samples. A mixed-method approach was employed for robust interpretation.

Results: Dementia patients had an increased serum AG and AG/UAG ratio. With the increase in AG among dementia subjects, a significant decrease in species richness was observed. Bifidobacterium longum, Eubacterium biforme, Fecalibacterium prausnitzii, Lactobacillus ruminis, and Prevotella copri contributed to substantial differences in beta-diversity. Blautia obeum was associated with Mini-Mental State Examination (MMSE), and Fecalibacterium prausnitzii was associated with Montreal Cognitive Assessment (MoCA) Scale.

Discussion: This pilot study indicates a complex interaction between AG, gut microbiome, and cognitive scores. Increased AG corresponds to both dementia and gut dysbiosis, intricately interconnecting the gut-brain axis. The circulating AG and associated gut microbiome might be a putative biomarker for dementia.