High Bile Acid-induced by High-fat Diet Impairs Intestinal Mucosa by Down-regulating Stem Cell Function / 胃肠病学

Background:High-fat diet leads to intestinal mucosa barrier dysfunction,but the mechanism is not clear. High-fat diet can induce increase of bile acid. Aims:To investigate whether the high bile acid induced by high-fat diet could act on intestinal stem cell to disrupt stem cell differentiation and imparing the intestinal mucosa. Methods:Twenty-four rats were divided into 3 groups:fed with regular diet,high-fat diet and high-fat diet + cholestyramine,respectively,for 2 weeks. Serum bile acid was detected by ELISA. Ileal diameter was measured and HE staining was performed to observe histology of intestinal mucosa. Expression of Lgr5 gene was determined by RT-qPCR. Ileal tissue fed with regular diet was cultured with deoxycholic acid(DCA)or DCA + cholestyramine for 24 hours in vitro,expression of Lgr5 gene was determined by RT-qPCR. Results:Compared with control group,serum bile acid was significantly increased(P < 0. 05),ileal diameter was significantly decreased,height of intestinal crypts and villus was significantly decreased(P < 0. 05),and expression of Lgr5 gene was significantly decreased in high-fat diet group(P < 0. 01). All the above-mentioned indices were significantly ameliorated in high-fat diet + cholestyramine group(P < 0. 05). In vitro study showed that expression of Lgr5 gene was significantly decreased in DCA group than in control group(P < 0. 01),and cholestyramine could significantly increase expression of Lgr5 gene(P < 0. 05). Conclusions:High-fat diet induced increasing of circulatory bile acid can cause injury of intestinal mucosa by inhibiting stem cell function,which can be ameliorated by cholestyramine.

Cholestyramine Use for Rapid Reversion to Euthyroid States in Patients with Thyrotoxicosis

Cholestyramine (CS) is an ion exchange resin, which binds to iodothyronines and would lower serum thyroid hormone level. The use of CS added to conventional antithyroid drugs to control thyrotoxicosis has been applied since 1980's, and several studies indicate that using CS in combination with methimazole (MZ) produces a more rapid decline in serum thyroid hormones than with only MZ treatment. Our recent retrospective review of five patients taking high dose MZ and CS, compared to age-, gender-, initial free thyroxine (T4) level-, and MZ dose-matched 12 patients with MZ use only, showed more rapid decline of both free T4 and triiodothyronine levels without more adverse events. CS could be safely applicable short-term adjunctive therapy when first-line antithyroid medications are not enough to adequately control severe thyrotoxicosis or side effects of antithyroid drug would be of great concern.

Refractory Graves' Disease Successfully Cured by Adjunctive Cholestyramine and Subsequent Total Thyroidectomy

The three major forms of treatment for Graves thyrotoxicosis are antithyroid drugs, radioactive iodine therapy and thyroidectomy. Surgery is the definitive treatment for Graves thyrotoxicosis that is generally recommended when other treatments have failed or are contraindicated. Generally, thyrotoxic patients should be euthyroid before surgery to minimize potential complications which usually requires preoperative management with thionamides or inorganic iodine. But several cases of refractory Graves' disease have shown resistance to conventional treatment. Here we report a 40-year-old female patient with Graves' disease who complained of thyrotoxic symptoms for 7 months. Her thyroid function test and thyroid autoantibody profiles were consistent with Graves' disease. One kind of thionamides and beta-blocker were started to control her disease. However, she was resistant to nearly all conventional medical therapies, including beta-blockers, inorganic iodine, and two thionamides. She experienced hepatotoxicity from the thionamides. What was worse is her past history of serious allergic reaction to corticosteroids, which are often used to help control symptoms. A 2-week regimen of high-dose cholestyramine improved her uncontrolled thyrotoxicosis and subsequent thyroidectomy was successfully performed. In conclusion, cholestyramine could be administered as an effective and safe adjunctive agent for preoperative preparation in patients with severe hyperthyroid Graves's disease that is resistant to conventional therapies.