Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome. . .
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or high producers ( ≥ 100 ng/mL). Six hours after drinking the PJ, plasma levels showed most subjects still did not display gut-mediated production of UA: 24% of subjects had detect- able, but low levels of UA glucuronide in circulation and only 4% subjects were above the 100 ng/mL threshold (Fig. 2B). The conversion of pomegranate precursors into UA was markedly increased 24-h after drinking PJ; however, still only ~40% of subjects displayed UA glucuronide plasma levels >100 ng/mL. The remaining 60% were still either unable to convert (33%) or were poor converters of UA (27%) (Fig. 2C).
different levels following PJ intake. This metagenomic analysis compared the abundance of MGS and genes in subjects from the no, low, and high producer groups. Metagenomic pro fi les determined the microbiome alpha diversity, which indicates variation of microbes in a single sample. Alpha diversity was assessed both as microbiome richness (number of species or genes observed in a sample) and microbiome variability, and was quanti fi ed using the Shannon index [17]. The Shannon index accounts for the number of species or genes in a community, and also their relative abundance. Results showed signi fi cantly higher richness in the microbiome Shannon index in both the low producers and high producers, when comparing each with the no pro- ducer group, for both MGS (Fig. 3A) and gene-based (Supplementary Fig. 2) measures. A second analysis
Gut microbiome plays an essential role in de fi ning UA producers
Shotgun sequencing determined microbiome composition from the fecal samples of individuals producing UA at
A
B
Microbiome richness
Shannon diversity
Bray-Curtis dissimilarity
*
*****
**
*
0.2
300
4
250
0.0
200
3
−0.2
150
100
2
−0.4
No UA Producer
High UA Producer
No UA Producer
−0.4
−0.2
0.0
0.2
High UA Producer
Low UA Producer
Low UA Producer
PCo1 (12 %)
D
C
No UA producer
Low UA producer
High UA producer
Firmicutes/Bacteroidetes
No UA producer (not detected) Low UA producer (5-99 ng/ml) High UA producer (>100ng/ml)
3
80
**
80
**
75
60
2
60
50
40
40
1
25
20
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Firmicutes Bacteroidetes
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Firmicutes Bacteroidetes
Fig. 3 Gut microbiome differences between UA producers and non-producers. A Boxplots showing differences in metagenomics species (MGS) for richness (left panel) and Shannon diversity (right panel) between groups with no, low, and high UA producer status. All groups were compared pairwise by Mann – Whitney U test (N = 99). * p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001; ***** p ≤ 0.00001. B Principal coordinate analysis (PCoA) based on Bray – Curtis dissimilarities among samples, calculated based on the MGS abundances. Samples are color coded by the UA producer status. Each sample is connected to its group centroid by a thin segment line. The ellipses cover two
standard errors of the mean of the group centroids, i.e., they illustrate the certainty of the group centroid positions. The x - and y -axis labels indicate the microbial variance explained by the fi rst two principal coordinates . C Relative abundance (in %) of phyla Firmicutes and Bacteroidetes that signi fi cantly differed in abundance in producer of UA compared with no producer. Boxes represent interquartile range (IQR), with the inside horizontal line representing the median. Whis- kers represent values within 1.5× IQR of the fi rst and third quartiles. D Firmicutes/Bacteroidetes ratio (F/B ratio) for each group shown as median (IQR). ** p ≤ 0.01 (Mann – Whitney U test).
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