Improved glucose metabolism following bariatric surgery is associated with increased circulating bile acid concentrations and remodeling of the gut microbiome

Table 1 Abundance of bacterial species in various sections of the human intestine

Intestine	Abundance of Bacteria	Bacteria
Small intestine
Duodenum	About 103 (bacteria/mL)	Lactobacillus1
		Streptococcus2
Jejunum	About 104 (bacteria/mL)	Lactobacillus1
		Streptococcus2
		Staphylococcus
		Veillonella2
Ileum	106-108 (bacteria/mL)	Enterobacteri1
		Enterococcus1
		Bacteroides12
		Clostridium12
		Lactobacillus1
		Veillonella
Large intestine	About 1011 (bacteria/g)	Bacteroides12
		Eubacterium2
		Bifidobacterium1
		Ruminococcus
		Peptostreptococcus
		Propionibacterium
		Clostridium12
		Lactobacillus1
		Escherichia
		Streptococcus2
		Methanobrevibacter

¹Bacteria displaying bile salt hydrolase (BSH) activity;

²Bacteria capable of catalyzing 7α-dehydroxylation. Based on data presented in[68].

Table 2 Composition of human biliary and fecal bile acids

Bile acids	Biliary bile acids composition (% of total)	Fecal bile acids composition (% of total)
Cholic acid (CA)	35%	2%
Chenodeoxycholic acid (CDCA)	35%	2%
Deoxycholic acid (DCA)	25%	34%
Ursodeoxycholic acid (UDCA)	2%	2%
Lithocholic acid (LCA)	1%	29%
12-oxo-Lithocholic acid (12-oxo-LCA)	-	3%
Other	2%	28%

Table shows percentage of both conjugated and unconjugated bile acids. Based on data presented in[68].

Table 3 Bile acids present in human serum. Based on data presented in[110]

Primary bile acids	Secondary bile acids
Cholic acid (CA)	Lithocholic acid (LCA)
Chenodeoxycholic acid (CDCA)	Deoxycholic acid (DCA)
Glycocholic acid (GCA)	Ursodeoxycholic acid (UDCA)
Glycochenodeoxycholic acid (GCDCA)	Hyodeoxycholic acid (HDCA)
Taurocholic acid (TCA)	Glycolithocholic acid (GLCA)
Taurochenodeoxycholic acid (TCDCA)	Glycodeoxycholic acid (GDCA)
	Glycoursodeoxycholic acid (GUDCA)
	Taurolithocholic acid (TLCA)
	Taurodeoxycholic acid (TDCA)
	Tauroursodeoxycholic acid (TUDCA)
	Taurohyodeoxycholic acid (THDCA)

Table 4 Effects of various bariatric procedures on diabetic parameters and serum bile acid concentrations

Patients	Type of bariatric procedure	Time interval from surgery to examination	Effect of surgery on diabetic parameters	Effect of surgery on serum bile acid concentrations	Ref.
Morbidly obese, n = 10	LAGB	Various (after losing 20% of body weight)	Not presented	Decreased fasting BAs; no change in postprandial BAs	[28]
Morbidly obese, n = 6, preoperative BMI = 44	Gastric banding	42 d	Not presented	No change	[138]
Morbidly obese, n = 28, BMI = 46.0	Gastric banding	6-28 mo	Decreased serum glucose	Decreased primary BAs	[145]
			Decreased serum insulin	No change in deoxycholic BAs
Morbidly obese, n = 7, BMI = 43	LSG	1 wk, 3 mo, 1 yr	Decreased HOMA-IR	Decreased BAs after 1 wk	[147]
				Increased BAs after 3 mo and 1 yr
Morbidly obese, n =18, BMI = 60	LSG	6 mo	Decreased: fasting glucose , fasting insulin, HOMA-IR and HBA1c	No change in total BAs	[148]
				Decreased primary BAs
				Increased secondary BAs
Obese females, n = 17, BMI = 43	LSG	24 mo	Decreased: HbA1c, insulin,	Increased total BAs	[29]
			HOMA-IR.
Morbidly obese, n =15, BMI = 45	LSG and LAGB	1 and 3 mo	Decreased: HbA1c, insulin and HOMA-IR	Increased total, primary and secondary BAs	[146]
Morbidly obese, n = 8	RYGB	Various (after losing 20% of body weight)	Not presented	Increased fasting and postprandial total and conjugated BAs	[28]
Morbidly obese, n = 9, preoperative BMI = 50	RYGB	2-4 yr	Lower fasting glucose and insulin	Higher total BA concentration	[103]
Morbidly obese, n = 37, nondiabetic, preoperative BMI = 48	RYGB	About 200 d	No change in fasting serum glucose	No change in BAs after surgery	[150]
Morbidly obese, n =75, diabetic, preoperative BMI = 48	RYGB	About 6 mo	Decreased fasting serum glucose and HbA1c	Increased total BAs	[150]
Severely obese women with T2DM, n = 13, preoperative BMI = 44	RYGB	1 mo and 2 yr	Decreased HOMA-IR	Reduced BAs after 1 mo	[32]
				Increased BAs after 2 yr
Obese patients, n = 63, BMI = 44	RYGB	15 mo	Decreased fasting glucose and HOMA-IR	Increased total BAs	[23]
Surgically obese, n = 5, BMI > 35	RYGB	1, 4, and 40 wk	Not presented	Increased conjugated BAs	[152]
				No changed unconjugated BAs
Obese females, n = 11, BMI = 44	RYGB	34 ± 16 mo	Increased postprandial insulin compared to controls	increased postprandial BAs comparing to controls	[149]
Morbidly obese, n = 30, BMI = 48	RYGB	8-13 mo	Decreased serum glucose and insulin concentration	Increased primary BAs, glycine BA, deoxycholic BA	[145]
Morbidly obese, n = 35, BMI = 48	RYGB	3 mo	Decreased HOMA-IR	Increased total BAs	[151]
Obese patients, n = 30, BMI = 46	RYGB	12 mo	Decreased fasting glucose and HOMA-IR	Increased total BAs, decreased taurine conjugated BAs	[153]
Morbidly obese, n = 7, BMI = 50	LRYGB	1 wk, 3 mo, 1 yr	Decreased HOMA-IR	Decreased BAs after 1 wk	[147]
				Increased BAs after 3 mo and 1 yr
Morbidly obese, n = 19, BMI = 43	LRYGB and LSG/DJB	1 and 3 mo	Decreased HBA1c, insulin, and HOMA-IR	Increased total, primary and secondary BA concentration	[146]
Morbidly obese, n = 12, preoperative BMI = 49	Gastric bypass	42 d	Not presented	Increased total BAs	[138]

LSG: Laparoscopic sleeve gastrectomy; LAGB: Laparoscopic adjustable gastric banding; LSG/DJB: LSG with duodeno-jejunal bypass; RYGB: Roux-en-Y gastric bypass; LRYGB: laparoscopic RYGB.