Gut Microbiota Contribute to Age-Related Changes in Skeletal Muscle Size, Composition, and Function: Biological Basis for a Gut-Muscle Axis

In the paper

“high-fat feeding is shown to compromise epithelial tight junctions and increase intestinal permeability [34, 35]”

What the sources say

• Not checked yetcites [34] Gulhane M, Murray L, Lourie R, Tong H, Sheng YH, Wang R, Kang A, Schreiber V, Wong KY, Magor G, Denman S, Begun J, Florin TH, Perkins A, Cuiv PO, McGuckin MA, Hasnain SZ (2016) High fat diets induce colonic epithelial cell stress and inflammation that is reversed by IL-22. Sci Rep 6:28990 source
• Not checked yetcites [35] Guo S, Al-Sadi R, Said HM, Ma TY (2013) Lipopolysaccharide causes an increase in intestinal tight junction permeability in vitro and in vivo by inducing enterocyte membrane expression and localization of TLR-4 and CD14. Am J Pathol 182:375–387 source

In the paper

“high-fat diet, which is known to induce chronic low-grade chronic inflammation (e.g., IL-1, IL-6, and TNF-α elevation), a reported contributor to insulin resistance [32, 33].”

What the sources say

• Not checked yetcites [32] Hotamisligil GS, Peraldi P, Budavari A, Ellis R, White MF, Spiegelman BM (1996) IRS-1-mediated inhibition of insulin receptor tyrosine kinase activity in TNF-alpha- and obesity-induced insulin resistance. Science 271:665–668 source
• Not checked yetcites [33] Senn JJ, Klover PJ, Nowak IA, Mooney RA (2002) Interleukin-6 induces cellular insulin resistance in hepatocytes. Diabetes 51:3391–3399 source

In the paper

“As expected, high-fat fed mice exhibited an increase in body weight and inflammatory markers as well as a decrease in glucose tolerance.”

What the sources say

• Not checked yetcites [18] Cani PD, Amar J, Iglesias MA, Poggi M, Knauf C, Bastelica D, Neyrinck AM, Fava F, Tuohy KM, Chabo C, Ferrie J, Gibson GR, Casteilla L, Delzenne NM, Alessi MC (2007) Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes 56:1761–1772 source

In the paper

“Endotoxin-mediated reductions in glucose tolerance have been similarly shown in humans inoculated with LPS, as evidenced by significant increases in skeletal muscle NF-κβ binding activity and JNK phosphorylation, which synergistically inhibit insulin signaling [36].”

What the sources say

• Not checked yetcites [36] Aguirre V, Uchida T, Yenush L, Davis R, White MF (2000) The c-Jun NH(2)-terminal kinase promotes insulin resistance during association with insulin receptor substrate-1 and phosphorylation of Ser(307). J Biol Chem 275:9047–9054 source

In the paper

“The composition of gut microbiota is shown to be dynamic throughout the lifespan, undergoing rapid changes from birth until ~ 3 years of age, after which greater stability is established [11, 12].”

What the sources say

• Not checked yetcites [11] Yatsunenko T, Rey FE, Manary MJ, Trehan I, Dominguez-Bello MG, Contreras M, Magris M, Hidalgo G, Baldassano RN, Anokhin AP, Heath AC, Warner B, Reeder J, Kuczynski J, Caporaso JG, Lozupone CA, Lauber C, Clemente JC, Knights D, Knight R, Gordon JI (2012) Human gut microbiome viewed across age and geography. Nature 486:222–227 source
• Not checked yetcites [12] Hill CJ, Lynch DB, Murphy K, Ulaszewska M, Jeffery IB, O’Shea C, Watkins C, Dempsey E, Mattivi F, Tuohy K, Ross RP, Ryan CA, O’Toole P, Stanton C (2017) Evolution of gut microbiota composition from birth to 24 weeks in the INFANTMET Cohort. Microbiome 5:4 source

In the paper

“associations between gut ecology and cancer [16], cardiovascular disease [17], obesity [6], diabetes [18], and muscle wasting [19]”

What the sources say

• Not checked yetcites [16] Yu LX, Yan HX, Liu Q, Yang W, Wu HP, Dong W, Tang L, Lin Y, He YQ, Zou SS, Wang C, Zhang HL, Cao GW, Wu MC, Wang HY (2010) Endotoxin accumulation prevents carcinogen-induced apoptosis and promotes liver tumorigenesis in rodents. Hepatology 52:1322–1333 source
• Not checked yetcites [17] Tang WH, Wang Z, Levison BS, Koeth RA, Britt EB, Fu X, Wu Y, Hazen SL (2013) Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med 368:1575–1584 source
• Not checked yetcites [19] Bindels LB, Beck R, Schakman O, Martin JC, de Backer F, Sohet FM, Dewulf EM, Pachikian BD, Neyrinck AM, Thissen JP, Verrax J, Calderon PB, Pot B, Grangette C, Cani PD, Scott KP, Delzenne NM (2012) Restoring specific lactobacilli levels decreases inflammation and muscle atrophy markers in an acute leukemia mouse model. PLoS ONE 7:1–10 source

In the paper

“in older individuals circulating LPS and skeletal muscle TLR4 (a receptor for LPS [43]) gene expression and protein content were higher, and insulin sensitivity (quantified by HOMA-IR) was lower than their younger counterparts.”

What the sources say

• Not checked yetcites [42] Ghosh S, Lertwattanarak R, Garduno Jde J, Galeana JJ, Li J, Zamarripa F, Lancaster JL, Mohan S, Hussey S, Musi N (2015) Elevated muscle TLR4 expression and metabolic endotoxemia in human aging. J Gerontol A Biol Sci Med Sci 70:232–246 source

In the paper

“Gut microbiota are emerging as a salient contributor to human health and disease [5], and their effects are particularly pronounced in older years [20].”

What the sources say

• Not checked yetcites [5] Shreiner AB, Kao JY, Young VB (2015) The gut microbiome in health and in disease. Curr Opin Gastroenterol 31:69–75 source
• Not checked yetcites [20] Lustgarten MS (2016) Classifying aging as a disease: the role of microbes. Front Genet 7:212 source

In the paper

“These studies and others [30, 37], show that circulating LPS, a prominent component of gut microbiota, induces skeletal muscle inflammation and insulin resistance thereby contributing to the development of metabolic syndrome.”

What the sources say

• Not checked yetcites [30] Choi Y, Kwon Y, Kim D-K, Jeon J, Jang SC, Wang T, Ban M, Kim M-H, Jeon SG, Kim M-S, Choi CS, Jee Y-K, Gho YS, Ryu SH, Kim Y-K (2015) Gut microbe-derived extracellular vesicles induce insulin resistance, thereby impairing glucose metabolism in skeletal muscle. Sci Rep 5:15878 source
• Not checked yetcites [37] Liang H, Hussey SE, Sanchez-Avila A, Tantiwong P, Musi N (2013) Effect of lipopolysaccharide on inflammation and insulin action in human muscle. PLoS ONE 8:e63983 source

In the paper

“in response to the gut microbiota-specific metabolite indoxyl sulfate [38], C2C12 myoblasts exhibit an up-regulation of glycolysis and an increase in the activity of the pentose phosphate pathway [39].”

What the sources say

• Not checked yetcites [38] Wikoff WR, Anfora AT, Liu J, Schultz PG, Lesley SA, Peters EC, Siuzdak G (2009) Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites. Proc Natl Acad Sci USA 106:3698–3703 source
• Not checked yetcites [39] Sato E, Mori T, Mishima E, Suzuki A, Sugawara S, Kurasawa N, Saigusa D, Miura D, Morikawa-Ichinose T, Saito R, Oba-Yabana I, Oe Y, Kisu K, Naganuma E, Koizumi K, Mokudai T, Niwano Y, Kudo T, Suzuki C, Takahashi N, Sato H, Abe T, Niwa T, Ito S (2016) Metabolic alterations by indoxyl sulfate in skeletal muscle induce uremic sarcopenia in chronic kidney disease. Sci Rep 6:36618 source

In the paper

“TNF-α and IL-6 are strongly induced by circulating LPS [53] and elevated in aging individuals [54, 55].”

What the sources say

• Not checked yetcites [53] Frost RA, Nystrom GJ, Lang CH (2002) Lipopolysaccharide regulates proinflammatory cytokine expression in mouse myoblasts and skeletal muscle. Am J Physiol Regul Integr Comp Physiol 283:R698–R709 source
• Not checked yetcites [54] Bruunsgaard H, Andersen-Ranberg K, Jeune B, Pedersen AN, Skinhoj P, Pedersen BK (1999) A high plasma concentration of TNF-alpha is associated with dementia in centenarians. J Gerontol A Biol Sci Med Sci 54:M357–M364 source
• Not checked yetcites [55] Maggio M, Guralnik JM, Longo DL, Ferrucci L (2006) Interleukin-6 in aging and chronic disease: a magnificent pathway. J Gerontol A Biol Sci Med Sci 61:575–584 source

In the paper

“adipose tissue infiltration in skeletal muscle (i.e., change in muscle composition) has been shown to increase with age [81] and is associated with mobility impairment [82].”

What the sources say

• Not checked yetcites [81] Goodpaster BH, Carlson CL, Visser M, Kelley DE, Scherzinger A, Harris TB, Stamm E (1985) Newman AB (2001) Attenuation of skeletal muscle and strength in the elderly: the health ABC study. J Appl Physiol 90:2157–2165 source
• Not checked yetcites [82] Visser M, Kritchevsky SB, Goodpaster BH, Newman AB, Nevitt M, Stamm E, Harris TB (2002) Leg muscle mass and composition in relation to lower extremity performance in men and women aged 70 to 79: the health, aging and body composition study. J Am Geriatr Soc 50:897–904 source

In the paper

“Coupling of these microbial alterations with restoration of intestinal homeostasis (e.g., increase tight junction proteins) and a reduction in muscle wasting suggests that Lactobacillus and Bifidobacterium may influence gut-muscle communication and regulate muscle size.”

In the paper

“the authors reported an increase in circulating inflammatory cytokines (IL-6, TNF-α, and MCP-1) and intramuscular fat after just 3 days [85]”

What the sources say

• Not checked yetcites [85] Collins KH, Paul HA, Hart DA, Reimer RA, Smith IC, Rios JL, Seerattan RA, Herzog W (2016) A high-fat high-sucrose diet rapidly alters muscle integrity, inflammation and gut microbiota in male rats. Sci Rep 6:37278 source

In the paper

“the tryptophan derivative indoxyl sulfate, which is similarly shown to increase with age [60], is reported to induce inflammatory cytokine expression (IL-6 and TNF-α) and markers of muscle atrophy (myostatin and atrogin-1) similar to that of LPS in cultured myocytes [61].”

What the sources say

• Not checked yetcites [60] Wyczalkowska-Tomasik A, Czarkowska-Paczek B, Giebultowicz J, Wroczynski P, Paczek L (2017) Age-dependent increase in serum levels of indoxyl sulphate and p-cresol sulphate is not related to their precursors: tryptophan and tyrosine. Geriatr Gerontol Int 17:1022–1026 source
• Not checked yetcites [61] Enoki Y, Watanabe H, Arake R, Sugimoto R, Imafuku T, Tominaga Y, Ishima Y, Kotani S, Nakajima M, Tanaka M, Matsushita K, Fukagawa M, Otagiri M, Maruyama T (2016) Indoxyl sulfate potentiates skeletal muscle atrophy by inducing the oxidative stress-mediated expression of myostatin and atrogin-1. Sci Rep 6:32084 source

In the paper

“sepsis, a life-threatening illness characterized by severe muscle wasting due to both increases in proteolytic degradation and reductions in protein synthesis [52].”

What the sources say

• Not checked yetcites [52] Callahan LA, Supinski GS (2009) Sepsis-induced myopathy. Crit Care Med 37:S354–S367 source

In the paper

“obesity appears to exacerbate the progression of sarcopenia by compounding inflammatory burden [45], resulting in a state of sarcopenic obesity”

What the sources say

• Not checked yetcites [45] Cesari M, Kritchevsky SB, Baumgartner RN, Atkinson HH, Penninx BW, Lenchik L, Palla SL, Ambrosius WT, Tracy RP, Pahor M (2005) Sarcopenia, obesity, and inflammation–results from the trial of angiotensin converting enzyme inhibition and novel cardiovascular risk factors study. Am J Clin Nutr 82:428–434 source

In the paper

“Follow-up analyses confirmed the favorable effect of prebiotic feeding on gut microbiota, as was evidenced by a shift in the ratio of Bacteroidetes/Firmicutes in addition to increases in the levels of Lactobacillus and Bifidobacterium spp. [66].”

What the sources say

• Not checked yetcites [66] Everard A, Lazarevic V, Derrien M, Girard M, Muccioli GG, Neyrinck AM, Possemiers S, Van Holle A, Francois P, de Vos WM, Delzenne NM, Schrenzel J, Cani PD (2011) Responses of gut microbiota and glucose and lipid metabolism to prebiotics in genetic obese and diet-induced leptin-resistant mice. Diabetes 60:2775–2786 source

In the paper

“A variety of phenomena have been proposed to contribute to this age-related heightened inflammatory state including redox stress [46], immuno- and endocrine senescence [47, 48], DNA damage [49], epigenetic modification [50], and a distortion of gut microbial homeostasis [51] that is associated with increased levels of circulating endotoxin [42].”

What the sources say

• Not checked yetcites [46] Sohal RS, Orr WC (2012) The redox stress hypothesis of aging. Free Radic Biol Med 52:539–555 source
• Not checked yetcites [47] Franceschi C, Bonafe M, Valensin S (2000) Human immunosenescence: the prevailing of innate immunity, the failing of clonotypic immunity, and the filling of immunological space. Vaccine 18:1717–1720 source
• Not checked yetcites [48] Maggio M, Basaria S, Ble A, Lauretani F, Bandinelli S, Ceda GP, Valenti G, Ling SM, Ferrucci L (2006) Correlation between testosterone and the inflammatory marker soluble interleukin-6 receptor in older men. J Clin Endocrinol Metab 91:345–347 source
• Not checked yetcites [51] Cevenini E, Caruso C, Candore G, Capri M, Nuzzo D, Duro G, Rizzo C, Colonna-Romano G, Lio D, Di Carlo D, Palmas MG, Scurti M, Pini E, Franceschi C, Vasto S (2010) Age-related inflammation: the contribution of different organs, tissues and systems. How to face it for therapeutic approaches. Curr Pharm Des 16:609–618 source

In the paper

“an age-related decrease in gut Bifidobacterium content may underlie increases in circulating endotoxin that are shown to induce skeletal muscle atrophy [71].”

What the sources say

• Not checked yetcites [71] Morales MG, Olguin H, Di Capua G, Brandan E, Simon F, Cabello-Verrugio C (2015) Endotoxin-induced skeletal muscle wasting is prevented by angiotensin-(1-7) through a p38 MAPK-dependent mechanism. Clin Sci (Lond) 129:461–476 source

In the paper

“Macrophage production of TNF-α is shown to occur early in the stress response, and has been demonstrated to stimulate protein degradation and apoptosis in cultured cells [56, 57].”

What the sources say

• Not checked yetcites [56] Li YP, Chen Y, John J, Moylan J, Jin B, Mann DL, Reid MB (2005) TNF-alpha acts via p38 MAPK to stimulate expression of the ubiquitin ligase atrogin1/MAFbx in skeletal muscle. FASEB J 19:362–370 source
• Not checked yetcites [57] Baxter GT, Kuo RC, Jupp OJ, Vandenabeele P, MacEwan DJ (1999) Tumor necrosis factor-alpha mediates both apoptotic cell death and cell proliferation in a human hematopoietic cell line dependent on mitotic activity and receptor subtype expression. J Biol Chem 274:9539–9547 source

In the paper

“Bifidobacterium are shown to decrease with age [68], and are associated with lower intestinal [69] and circulating LPS levels [70].”

What the sources say

• Not checked yetcites [68] Enck P, Zimmermann K, Rusch K, Schwiertz A, Klosterhalfen S, Frick JS (2009) The effects of ageing on the colonic bacterial microflora in adults. Z Gastroenterol 47:653–658 source
• Not checked yetcites [69] Griffiths EA, Duffy LC, Schanbacher FL, Qiao H, Dryja D, Leavens A, Rossman J, Rich G, Dirienzo D, Ogra PL (2004) In vivo effects of bifidobacteria and lactoferrin on gut endotoxin concentration and mucosal immunity in Balb/c mice. Dig Dis Sci 49:579–589 source
• Not checked yetcites [70] Cani PD, Neyrinck AM, Fava F, Knauf C, Burcelin RG, Tuohy KM, Gibson GR, Delzenne NM (2007) Selective increases of bifidobacteria in gut microflora improve high-fat-diet-induced diabetes in mice through a mechanism associated with endotoxaemia. Diabetologia 50:2374–2383 source

In the paper

“Collins et al. subjected young rats to a high-fat high-sucrose diet and found an increase in Enterobacteriaceae (gram-negative member of the Proteobacteria phylum) and a decrease in the abundance of Lactobacillus spp., changes that have been similarly reported with aging [83, 84].”

What the sources say

• Not checked yetcites [83] Biagi E, Nylund L, Candela M, Ostan R, Bucci L, Pini E, Nikkila J, Monti D, Satokari R, Franceschi C, Brigidi P, De Vos W (2010) Through ageing, and beyond: gut microbiota and inflammatory status in seniors and centenarians. PLoS ONE 5:e10667 source
• Not checked yetcites [84] van Tongeren S, Slaets J, Harmsen H, Welling G (2005) Fecal microbiota composition and frailty. Appl Environ Microbiol 71:6438–6442 source

In the paper

“aging muscle appears to undergo a fast-to-slow fiber-type shift [91], that is hypothesized to reduce whole muscle power and increase fall risk [92, 93].”

What the sources say

• Not checked yetcites [91] Larsson L, Grimby G, Karlsson J (1979) Muscle strength and speed of movement in relation to age and muscle morphology. J Appl Physiol Respir Environ Exerc Physiol 46:451–456
• Not checked yetcites [92] Korhonen MT, Cristea A, Alen M, Hakkinen K, Sipila S, Mero A, Viitasalo JT, Larsson L (1985) Suominen H (2006) Aging, muscle fiber type, and contractile function in sprint-trained athletes. J Appl Physiol 101:906–917 source
• Not checked yetcites [93] Reid KF, Fielding RA (2012) Skeletal muscle power: a critical determinant of physical functioning in older adults. Exerc Sport Sci Rev 40:4–12 source

In the paper

“administration of a synbiotic containing inulin-type fructans and Lactobacillus reuteri was shown to reverse increases in Escherichia and promoted proliferation of Lactobacillus and Bifidobacterium in leukaemic mice [67].”

What the sources say

• Not checked yetcites [67] Bindels LB, Neyrinck AM, Claus SP, Le Roy CI, Grangette C, Pot B, Martinez I, Walter J, Cani PD, Delzenne NM (2016) Synbiotic approach restores intestinal homeostasis and prolongs survival in leukaemic mice with cachexia. ISME J 10:1456–1470 source

In the paper

“these findings demonstrate the ability of LPS-associated cytokines to determinately affect protein equilibrium (i.e., synthesis and breakdown), and suggest that elevated endotoxin levels with age may contribute to reductions in muscle mass.”

In the paper

“Cani et al., who showed a decrease in circulating LPS and inflammation and an increase in muscle mass in obese mice fed the prebiotic fiber oligofructose [65].”

What the sources say

• Not checked yetcites [65] Cani PD, Possemiers S, Van de Wiele T, Guiot Y, Everard A, Rottier O, Geurts L, Naslain D, Neyrinck A, Lambert DM, Muccioli GG, Delzenne NM (2009) Changes in gut microbiota control inflammation in obese mice through a mechanism involving GLP-2-driven improvement of gut permeability. Gut 58:1091–1103 source

In the paper

“the leukemic mice were given an oral probiotic containing Lactobacillus reuteri and L. gasseri that appeared to decrease serum levels of inflammatory cytokines (IL-6 and MCP-1) and atrogene expression (MuRF1 and Atrogin-1) in conjunction with an increase in mass of the tibialis anterior.”

What the sources say

• Not checked yetcites [19] Bindels LB, Beck R, Schakman O, Martin JC, de Backer F, Sohet FM, Dewulf EM, Pachikian BD, Neyrinck AM, Thissen JP, Verrax J, Calderon PB, Pot B, Grangette C, Cani PD, Scott KP, Delzenne NM (2012) Restoring specific lactobacilli levels decreases inflammation and muscle atrophy markers in an acute leukemia mouse model. PLoS ONE 7:1–10 source

In the paper

“Age-related changes in skeletal muscle size and composition summate to yield reductions in skeletal muscle function (strength and power) [77] that ultimately affect physical performance and the ability to live independently [95].”

What the sources say

• Not checked yetcites [77] Reid KF, Naumova EN, Carabello RJ, Phillips EM, Fielding RA (2008) Lower extremity muscle mass predicts functional performance in mobility-limited elders. J Nutr Health Aging 12:493–498 source
• Not checked yetcites [95] Bean JF, Leveille SG, Kiely DK, Bandinelli S, Guralnik JM, Ferrucci L (2003) A comparison of leg power and leg strength within the InCHIANTI study: which influences mobility more? J Gerontol A Biol Sci Med Sci 58:728–733 source

In the paper

“Comparison of microbial diversity among these athletes and both healthy normal weight (BMI ≤ 25) and overweight (BMI ≥ 28) age-matched controls elicited a hierarchical pattern (athletes > healthy > overweight), suggesting an association between microbial diversity, body composition, and physical function.”

What the sources say

• Not checked yetcites [101] Clarke SF, Murphy EF, O’Sullivan O, Lucey AJ, Humphreys M, Hogan A, Hayes P, O’Reilly M, Jeffery IB, Wood-Martin R, Kerins DM, Quigley E, Ross RP, O’Toole PW, Molloy MG, Falvey E, Shanahan F, Cotter PD (2014) Exercise and associated dietary extremes impact on gut microbial diversity. Gut 63:1913–1920 source

In the paper

“transfer of gut microbiota from an obese pig to a GF mouse replicated the host myocellular phenotype, which mirrored that of aging skeletal muscle (i.e., fast fiber atrophy concomitant with a fast-to-slow fiber type shift).”

What the sources say

• Not checked yetcites [94] Yan H, Diao H, Xiao Y, Li W, Yu B, He J, Yu J, Zheng P, Mao X, Luo Y, Zeng B, Wei H, Chen D (2016) Gut microbiota can transfer fiber characteristics and lipid metabolic profiles of skeletal muscle from pigs to germ-free mice. Sci Rep 6:31786 source

In the paper

“The beneficial changes in gut health seen with exercise training implicate skeletal muscle contraction as a regulator of microbial composition, and provide evidence for bi-directional gut-muscle effects.”

In the paper

“butyrate is shown to enhance intestinal barrier function by reinforcing tight junction assembly [96], which, in theory, should prevent endotoxin translocation and reduce circulating inflammation [97].”

What the sources say

• Not checked yetcites [96] Peng L, Li ZR, Green RS, Holzman IR, Lin J (2009) Butyrate enhances the intestinal barrier by facilitating tight junction assembly via activation of AMP-activated protein kinase in Caco-2 cell monolayers. J Nutr 139:1619–1625 source
• Not checked yetcites [97] Cox MA, Jackson J, Stanton M, Rojas-Triana A, Bober L, Laverty M, Yang X, Zhu F, Liu J, Wang S, Monsma F, Vassileva G, Maguire M, Gustafson E, Bayne M, Chou CC, Lundell D, Jenh CH (2009) Short-chain fatty acids act as antiinflammatory mediators by regulating prostaglandin E(2) and cytokines. World J Gastroenterol 15:5549–5557 source

In the paper

“investigations of age-related changes in gut microbiota describe a bacterial community that is both less diverse and lacking in microorganisms responsible for the production of butyrate (indicative of gastrointestinal health) [15, 84, 98, 99], and more abundant in pathogens belonging to the Proteobacteria phylum (e.g., Enterobacteriaceae) [15, 68, 83].”

What the sources say

• Not checked yetcites [15] Rampelli S, Candela M, Turroni S, Collino EB, Franceschi C, O’Toole PW, Brigidi P (2013) Functional metagenomic profiling of intestinal microbiome in extreme ageing. Aging 5:902–912 source
• Not checked yetcites [84] van Tongeren S, Slaets J, Harmsen H, Welling G (2005) Fecal microbiota composition and frailty. Appl Environ Microbiol 71:6438–6442 source
• Not checked yetcites [98] Claesson MJ, Jeffery IB, Conde S, Power SE, O’Connor EM, Cusack S, Harris HMB, Coakley M, Lakshminarayanan B, O’Sullivan O, Fitzgerald GF, Deane J, O’Connor M, Harnedy N, O’Connor K, O’Mahony D, van Sinderen D, Wallace M, Brennan L, Stanton C, Marchesi JR, Fitzgerald AP, Shanahan F, Hill C, Ross RP, O’Toole PW (2012) Gut microbiota composition correlates with diet and health in the elderly. Nature 9:178–184 source
• Not checked yetcites [99] Jeffery IB, Lynch DB, O’Toole PW (2016) Composition and temporal stability of the gut microbiota in older persons. ISME J 10:170–182 source
• Not checked yetcites [68] Enck P, Zimmermann K, Rusch K, Schwiertz A, Klosterhalfen S, Frick JS (2009) The effects of ageing on the colonic bacterial microflora in adults. Z Gastroenterol 47:653–658 source
• Not checked yetcites [83] Biagi E, Nylund L, Candela M, Ostan R, Bucci L, Pini E, Nikkila J, Monti D, Satokari R, Franceschi C, Brigidi P, De Vos W (2010) Through ageing, and beyond: gut microbiota and inflammatory status in seniors and centenarians. PLoS ONE 5:e10667 source

In the paper

“Associated with these changes is a decrease in the integrity of epithelial tight junctions and increased intestinal permeability [14], facilitating the translocation of microbial byproducts into circulation.”

What the sources say

• Not checked yetcites [14] Thevaranjan N, Puchta A, Schulz C, Naidoo A, Szamosi JC, Verschoor CP, Loukov D, Schenck LP, Jury J, Foley KP, Schertzer JDL, Maggie J, Davidson DJ, Verd EF, Surette MG, Bowdish D (2017) Age-associated microbial dysbiosis promotes intestinal permeability, systemic inflammation, and macrophage dysfunction. Cell Host Microbe 21:455–466 source

In the paper

“Research in murine models has begun to identify microbial targets with likely skeletal muscle ramifications.”

In the paper

“these findings advocate that exercise training is an effective means to promote beneficial changes in gut microbial health that seem to reduce circulating inflammation and support the maintenance of muscle mass and function.”

In the paper

“institutionalized elderly had a greater abundance of Enterobacteriaceae and Escherichia/Shigella, and less gut microbial diversity when compared with the community dwellers.”

What the sources say

• Not checked yetcites [98] Claesson MJ, Jeffery IB, Conde S, Power SE, O’Connor EM, Cusack S, Harris HMB, Coakley M, Lakshminarayanan B, O’Sullivan O, Fitzgerald GF, Deane J, O’Connor M, Harnedy N, O’Connor K, O’Mahony D, van Sinderen D, Wallace M, Brennan L, Stanton C, Marchesi JR, Fitzgerald AP, Shanahan F, Hill C, Ross RP, O’Toole PW (2012) Gut microbiota composition correlates with diet and health in the elderly. Nature 9:178–184 source