Western Diet and Colitis

This post covers a Chinese study testing the hypothesis that the so called “Western Style Diet” for 9 weeks could influence they way mice respond to 2,4,6 trinitrobenzene sulfonic acid to induce colitis. Trinitrobenzene sulfonic acid has a very interesting reaction scheme illustrated in the featured image. The authors were doing three things: (1) creating protein adducts, (2) releasing sulfate, and introducing a ligand for a transcription factor as will be discussed.

Lin L, Li Y, Zhou G, Wang Y, Li L, Han J, Chen M, He Y, Zhang S. Multi-Omics Analysis of Western-style Diet Increased Susceptibility to Experimental Colitis in Mice. J Inflamm Res. 2022 Apr 21;15:2523-2537. PMC free article

Supplementary Table 1 Ingredients of Mice Chow

These authors fed experimental mice a WSD and a control diet from weaning. After 9 weeks, the mice were treated with 2,4,6 trinitrobenzene sulfonic (TNBS) acid to induce colitis, and the control group was treated with 50% ethanol (commonly used IBD animal model).

The big difference seems to be in carbs from corn starch versus sucrose. The HFHC-C7 appears to be a more adult version of the AIN93G starter diet. From a human diet perspective, whole grain corn would have been more healthy. The Western diet seems to have fat calories coming from milk fat as opposed to vegetable oils. Neither die seems to contain any indigestible carbohydrate to support microbiome growth. Maltodextrin is digestible and can cause spikes in blood glucose and maybe even alter the microbiome in negative ways according to Medical News. It should be noted that the WSD did it’s job by damaging the livers of the mice.

	HFHC			HFHC-C7			AIN93G
Ingredient	kcal/gram	gram	kcal	kcal/gram	gram	kcal	kcal/gram	gram
Caisein	4	195	780	4	195	780	4	200	800
L-Cystine	0	0	0	0	0	0	4	3	12
DL-Methionine	4	3	12	4	3	12	0	0	0
Sucrose	4	341	1364	4	0	0	4	100	400
Cornstarch	4	150	600	4	695.4	2782	4	397.5	1590
Dyetrose	0	0	0	0	0	0	4	132	528
Soybean oil	0	0	0	0	0	0	9	70	630
Corn oil	0	0	0	9	52.5	472	0	0	0
Maltodextrin 10	0	0	0	4	150	600	0	0	0
Milkfat	9	210	1890	9	0	0	0	0	0
Ethoxyquin	0	0.04	0	0	0.04	0	0	0	0
Cellulose	0	50	0	0	50	0	0	50	0
Mineral Mix #200000	0	35	0	0	35	0	0	0	0
Mineral Mix #210025	0	0	0	0	0	0	0	35	0
Calcium Carbonate	0	4	0	0	4	0	0	0	0
Vitamin Mix #300050	4	10	40	4	10	40	0	0	0

The analytical techniques

Genome-wide microarray and liquid chromatography-tandem mass spectrometry were used to identify the differential transcripts and metabolites of experimental colitis with and without pre-illness WSD. This is how the two diets compared

TNBS binds to the acryl hydrocarbon receptor (AhR). AhR binds to the acryl hydrocarbon response element and induces the transcription of genes for cytochrome P450s that make all sorts of modifications to xenobiotics.

Brief recap of histology and gross biology

1. Western diet made TNBS induced colonic shortening and histopathological score slightly worse
2. In control animals , not treated with TNBS, the length of colon and weight gain over time were the same. The hepatic score was worse in the Western diet mice

Gene Pathways

Supplementary Table 5 Differentially Expressed Gene KEGG Pathways between the WSD-TNBS Group and the AIN93G-HFHCC7-TNBS Group. In retrospect, maybe I should have left in the xenobiotic metabolizing pathway stuff. The ones involving what we’ve been talking about are highlighted. Do changes in tryptophan metabolism and serotonin neurons change colonic transit time in Western vs control diet in mice treated with TNBS?

Pathway ID	Pathway	Number of Involved Genes	Upregulation/Downregulation	P Value
mmu04360	Axon guidance	28	Up	2.0E-04
mmu04261	Adrenergic signaling in cardiomyocytes	23	Up	9.8E-04
mmu05032	Morphine addiction	16	Up	1.9E-03
mmu00920	Sulfur metabolism	4	Up	3.4E-03
mmu04727	GABAergic synapse	13	Up	1.9E-02
mmu00512	Mucin type O-glycan biosynthesis	6	Up	1.9E-02
mmu04071	Sphingolipid signaling pathway	16	Up	2.8E-02
mmu04921	Oxytocin signaling pathway	19	Up	2.9E-02
mmu04020	Calcium signaling pathway	22	Up	2.9E-02
mmu04725	Cholinergic synapse	15	Up	2.9E-02
mmu04724	Glutamatergic synapse	15	Up	3.1E-02
mmu04728	Dopaminergic synapse	17	Up	3.4E-02
mmu04713	Circadian entrainment	13	Up	4.1E-02
mmu04976	Bile secretion	10	Up	4.8E-02
mmu04740	Olfactory transduction	167	Down	3.1E-15
mmu00790	Folate biosynthesis	8	Down	9.7E-04
mmu00380	Tryptophan metabolism	11	Down	1.2E-03
mmu04080	Neuroactive ligand-receptor interaction	38	Down	3.8E-03
mmu00480	Glutathione metabolism	12	Down	6.5E-03
mmu04726	Serotonergic synapse	19	Down	1.5E-02

The metabolome

I really don’t put much stock in the diet as really being “Western.” The metabolites and hormones they detected by electrospray ionization mass spectrometry are interesting. They saw a lot of modifications of short chain fatty acids too.

Supplementary Table 6 Metabolites Differentially Expressed in the Colonic Tissue between the WSD-TNBS Group and the AIN93G-HFHCC7-TNBS Group

Metabolite	Formula	Fold Change
Aldosterone	C21H28O5	0.02
Capric acid	C10H20O2	3.93
Xanthine	C5H4N4O2	18.62
cis-5-Dodecenoic acid	C12H22O2	6.50
4-(2-Aminophenyl)-2,4-dioxobutanoic acid	C10H9NO4	0.10
5-Hydroxytryptophol	C10H11NO2	0.08
Undecanoic acid	C11H22O2	2.90
10,13,16-Docosatriynoic acid	C22H32O2	3.00
trans-Dehydroandrosterone	C19H28O2	0.37
10-Hendecenoic acid	C11H20O2	4.12
21:3(5Z,14Z,17Z)	C21H36O2	5.12
19-Hydroxytestosterone	C19H28O3	2.96
Lauric acid	C12H24O2	5.65
Kynurenic acid	C10H7NO3	0.34
10-[5]-ladderane-decanoic acid	C22H34O2	0.18
Uridine monophosphate (UMP)	C9H13N2O9P	16.00
5Z,7E,9E,14Z,17Z-eicosapentaenoic acid	C20H30O2	16.00
7-octenoic acid	C8H14O2	0.17
Biliverdin	C33H34N4O6	5.83
5-trans-PGE2	C20H32O5	0.32
Riboflavin (Vitamin B2)	C17H20N4O6	0.47
Sphinganine	C18H39NO2	4.73
1,2-Dehydroreticuline	C19H22NO4	0.12
5-Hydroxytryptophol	C10H11NO2	0.13
4-Trimethylammoniobutanoic acid	C7H16NO2	5.33
Hypoxanthine	C5H4N4O	0.35
Indoleacetaldehyde	C10H9NO	0.14
Norepinephrine	C8H11NO3	0.33
3-Methoxytyrosine	C10H13NO4	0.30
5-methyl-hexanoic acid	C7H14O2	0.00
4-(2-Aminophenyl)-2,4-dioxobutanoic acid	C10H9NO4	0.15
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oic acid	C27H46O5	3.40
7Z, 10Z, 13Z, 16Z, 19Z-Docosapentaenoic acid	C22H34O2	0.24
LTB4	C20H32O4	0.30
Saccharopine	C11H20N2O6	0.06
L-threo-7,8-Dihydrobiopterin	C9H13N5O3	2.16
Phenylacetylglycine	C10H11NO3	0.06
18:1(13Z)(17Me)	C19H36O2	4.76
5α-Dihydrotestosterone	C19H30O2	0.48
16-heptadecynoic acid	C17H30O2	0.45
Sphingosine	C18H37NO2	2.02

Supplementary Table 8

Pearson correlation analysis of differential genes and metabolites in the comparison of the WSD-TNBS group and AIN93G-HFHCC7-TNBS group. Whether the reader agrees with the authors on their definition of normal control diets and a Western diet, these results are very interesting. The main driver of differences seems to be cytochrom P450s Cyp11b1 and Cypa1a. Srd5a3 is a steroid reductase. Hsd17b6 is involved in androgen metabolism. A negative Pearson correlation coefficient indicates an inverse relationship. These results strongly suggest that the mRNA that they are measuring are being translated into enzymes that are active.

Gene	Metabolite	Pearson correlation coefficient	P value
Differential genes and metabolites in colonic tissue
Cyp11b1	Aldosterone	-0.903	2.101E-03
Cyp11b1	5Z,7E,9E,14Z,17Z-eicosapentaenoic acid	0.927	9.162E-04
Srd5a3	Aldosterone	-0.911	1.622E-03
Srd5a3	Phenylacetylglycine	-0.864	5.702E-03
Cyp1a1	7-octenoic acid	-0.932	7.570E-04
Cyp1a1	5-trans-PGE2	-0.902	2.156E-03
Hsd17b6	3-Methoxytyrosine	-0.928	8.770E-04

Supplemental data table

Linking

Notes: The red square represented differential genes, the green circle represented differential metabolites, the solid edge meant the Pearson Correlation Coefficient (PCC) >0.8, and the dotted line meant the PCC <−0.8. We were all intovaleric acid. Having Cyp2p20 or something increases 5-adetamido valerate… valerate with an imino group on the carboxyl group. Some other Cyp is putting a hydroxyl group on the 3rd carbon of butyrate… All of this in the blood plasma.

Conclusions and followup questions ?

These authors showed some pretty interesting interaction between two diets, neither of which would be optimal for humans, and a toxin that does at least three things. The results do raise followup questions:

1. What if the control rats were fed a diet considered healthy for humans with “prebiotic” carbohydrates?
2. What if the treatment group was given an inorganic sulfur compound like sulfate or sulfite?
3. What changes could be happening to the microbiome?