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Scott KA, Ida M, Peterson VL, Prenderville JA, Moloney GM, Izumo T, Murphy K, Murphy A, Ross RP, Stanton C, Dinan TG, Cryan JF. Revisiting Metchnikoff: Age-related alterations in microbiota-gut-brain axis in the mouse. Brain Behav Immun 2017; 65:20-32. [PMID: 28179108 DOI: 10.1016/j.bbi.2017.02.004] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 02/07/2023] Open
Abstract
Over the last decade, there has been increased interest in the role of the gut microbiome in health including brain health. This is by no means a new theory; Elie Metchnikoff proposed over a century ago that targeting the gut by consuming lactic acid bacteria such as those in yogurt, could improve or delay the onset of cognitive decline associated with ageing. However, there is limited information characterising the relationship between the behavioural and physiological sequelae of ageing and alterations in the gut microbiome. To this end, we assessed the behavioural, physiological and caecal microbiota profile of aged male mice. Older mice (20-21months old) exhibited deficits in spatial memory and increases in anxiety-like behaviours compared to younger mice (2-3months old). They also exhibited increased gut permeability, which was directly correlated with elevations in peripheral pro-inflammatory cytokines. Furthermore, stress exacerbated the gut permeability of aged mice. Examination of the caecal microbiota revealed significant increases in phylum TM7, family Porphyromonadaceae and genus Odoribacter of aged mice. This represents a shift of aged microbiota towards a profile previously associated with inflammatory disease, particularly gastrointestinal and liver disorders. Furthermore, Porphyromonadaceae, which has also been associated with cognitive decline and affective disorders, was directly correlated with anxiety-like behaviour in aged mice. These changes suggest that changes in the gut microbiota and associated increases in gut permeability and peripheral inflammation may be important mediators of the impairments in behavioural, affective and cognitive functions seen in ageing.
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Affiliation(s)
- Karen A Scott
- APC Microbiome Institute, University College Cork, Cork, Ireland
| | - Masayuki Ida
- Suntory Wellness Limited, Suntory World Research Centre, Kyoto, Japan
| | - Veronica L Peterson
- APC Microbiome Institute, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | | | - Gerard M Moloney
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Takayuki Izumo
- Suntory Wellness Limited, Suntory World Research Centre, Kyoto, Japan
| | - Kiera Murphy
- Teagasc Moorepark Food Research Centre, Fermoy, Co. Cork, Ireland
| | - Amy Murphy
- Teagasc Moorepark Food Research Centre, Fermoy, Co. Cork, Ireland
| | - R Paul Ross
- Department of Science, Engineering and Food Science, University College Cork, Cork, Ireland
| | | | - Timothy G Dinan
- APC Microbiome Institute, University College Cork, Cork, Ireland; Department of Psychiatry & Neurobehavioural Science, University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Institute, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
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Rass IT. Blood content of tyrosine is an index of glucocorticoid action on metabolism. BIOCHEMISTRY (MOSCOW) 2010; 75:353-66. [PMID: 20370614 DOI: 10.1134/s0006297910030120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucocorticoid hormones directly or indirectly control virtually all metabolic and physiological processes. Glucocorticoids are also shown to act on a multitude of genes, enzyme systems, and proinflammatory factors, but for these hormones there is no representative index of action on metabolism similar to glucose content in blood for insulin. The absence of such an index prevents the assessment of tissue provision with these hormones under various conditions and seems to be an essential cause of complications associated with the clinical use of glucocorticoid preparations. Considering specific features of tyrosine metabolism and data obtained experimentally and on a clinical model (adrenalectomy in rats and substitution therapy in endocrine disease), blood content of this amino acid seems promising as such an index. Based on comparing results of glucocorticoid treatment in patients with systemic lupus erythematosus with changes in their blood tyrosine contents, the pharmacological effect of glucocorticoid preparations is suggested to be mainly due to compensating a relative shortage of these hormones.
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Affiliation(s)
- I T Rass
- Center of Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Moscow, Russia.
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