Taurocholic acid

Diabetes Obes Metab. 2013 May;15(5):474-7.

Effects of rectal administration of taurocholic acid on glucagon-like peptide-1 and peptide YY secretion in healthy humans.[Pubmed: 23181598 ]

Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), secreted by enteroendocrine L-cells located most densely in the colon and rectum, are of fundamental importance in blood glucose and appetite regulation. In animal models, colonic administration of bile acids can stimulate GLP-1 and PYY by TGR5 receptor activation.
METHODS AND RESULTS:
We evaluated the effects of Taurocholic acid (TCA), administered as an enema, on plasma GLP-1 and PYY, as well as gastrointestinal sensations in 10 healthy male subjects, and observed that rectal administration of TCA promptly stimulated secretion of both GLP-1 and PYY, and increased fullness, in a dose-dependent manner.
CONCLUSIONS:
These observations confirm that topical application of bile acids to the distal gut may have potential for the management of type 2 diabetes and obesity.

Liver Int. 2007 May;27(4):558-68.

Cytoprotective effects of taurocholic acid feeding on the biliary tree after adrenergic denervation of the liver.[Pubmed: 17403196 ]

Cholangiopathies impair the balance between proliferation and apoptosis of cholangiocytes leading to the disappearance of bile ducts and liver failure. Taurocholic acid (TC) is essential for cholangiocyte proliferative and functional response to cholestasis. Bile acids and neurotransmitters co-operatively regulate the biological response of the biliary epithelium to cholestasis. Adrenergic denervation of the liver during cholestasis results in the damage of bile ducts. To verify whether TC feeding prevents the damage of the biliary tree induced by adrenergic denervation in the course of cholestasis.
METHODS AND RESULTS:
Rats subjected to bile duct ligation (BDL) and to adrenergic denervation were fed a TC-enriched diet, in the absence or presence of daily administration of the phosphatidyl-inositol-3-kinase (PI3K) inhibitor wortmannin for 1 week. TC prevented the induction of cholangiocyte apoptosis induced by adrenergic denervation. TC also restored cholangiocyte proliferation and functional activity, reduced after adrenergic denervation. TC prevented AKT dephosphorylation induced by adrenergic denervation. The cytoprotective effects of TC were abolished by the simultaneous administration of wortmannin.
CONCLUSIONS:
TC administration prevents the damage of the biliary tree induced by the adrenergic denervation of the liver. These novel findings open novel perspectives in the understanding of the potential of bile acids especially in post-transplant liver disease.

Placenta. 2014 Jul;35(7):496-500.

High concentraction of taurocholic acid induced apoptosis in HTR-8/SVneo cells via overexpression of ERp29 and activation of p38.[Pubmed: 24780196 ]

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific disease associated with a significant risk of fetal complications. Our previous study using an iTRAQ-based proteomics approach showed that ERp29 was overexpressed in the placenta tissue of ICP patients, which was an apoptosis-related protein and has not been investigated in the pathogenesis of ICP. The aim of this study was to explore the role of ERp29 in the mechanism of apoptosis in the placenta of ICP.
METHODS AND RESULTS:
HTR-8/SVneo cells were cultured and treated with different concentrations of Taurocholic acid (TCA) (0, 10, 50 and 100 μM). The apoptotic index and cell cycle were detected by flow cytometry; furthermore, the expression levels of ERp29 and p-p38 were detected by western blot. The ERp29-siRNA was also used to confirm the role of ERp29 in TCA induced-apoptosis. ERp29 expression and the apoptotic index were significantly increased in HTR-8/SVneo cells exposed to 100 μM TCA; so were p-p38 and caspase-3 activity, compared with the 50 μM, 10 μM TCA groups and negative control group (P < 0.05, respectively). The induction of apoptosis by TCA and the expression of p-p38 were reduced in HTR-8/SVneo cells after treatment with ERp29-siRNA, compared with controls (P < 0.05, respectively).
CONCLUSIONS:
This study suggested that overexpression of ERp29 may play a key role in TCA-induced apoptosis in HTR-8/SVneo cells via activation of p38, which may participate in the pathogenesis of ICP and may represent a novel target for ICP treatment.

Exp Biol Med (Maywood). 2007 Jul;232(7):942-9.

Taurocholic acid feeding prevents tumor necrosis factor-alpha-induced damage of cholangiocytes by a PI3K-mediated pathway.[Pubmed: 17609511]

Cholangiopathies, such as primary biliary cirrhosis and primary sclerosis cholangitis, are characterized at the end stage by ductopenia due to increased cholangiocyte apoptosis and decreased cholangiocyte proliferation. Although cholangiocyte proliferation is associated with an increased number of intra-hepatic bile ducts and secretin-stimulated ductal secretion, ductopenia is coupled with decreased ductal mass and secretin-induced ductal secretory activity.
METHODS AND RESULTS:
We have shown that a single injection of actinomycin D + tumor necrosis factor-alpha (TNF-alpha ) to bile duct-ligated (BDL) rats induces cholangiocyte injury, which is characterized by loss of cholangiocyte proliferation, and secretory activity and by an increase in cholangiocyte apoptosis. We also have shown that Taurocholic acid both in vivo and in vitro stimulates cholangiocyte proliferation. We hypothesize that Taurocholic acid feeding protects cholangiocytes against TNF-alpha -induced apoptosis through a phosphatidylinositol-3-kinase (PI3K)-dependent pathway. Immediately after BDL, rats were fed Taurocholic acid or control diet in the absence/presence of daily injections of wortmannin for 1 week. Seven days later, control-fed or Taurocholic acid-fed rats were treated with a single intraperitoneal injection of actinomycin D + TNF-alpha . Twenty-four hours later we evaluated: (i) cholangiocyte apoptosis and proliferation in liver sections and (ii) basal and secretin-stimulated bile and bicarbonate secretion in bile fistula rats.
CONCLUSIONS:
Taurocholic acid feeding prevented TNF-alpha -induced increases in cholangiocyte apoptosis and decreases in growth and secretin-stimulated bile and bicarbonate secretion, changes that were blocked by PI3K inhibition. The PI3K survival pathway is important in bile acid protection against immune-mediated cholangiocyte injury in cholestatic liver diseases.