- 學位論文
Lactobacillus paracasei 乳酸菌抑制胃幽門螺旋桿菌感染之探討
Suppressive Effect of Lactobacillus paracasei on Helicobacter pylori Infection
摘要
胃幽門螺旋桿菌是造成胃癌的重要危險因子，目前臨床治療胃幽門螺旋桿菌多採用三合一療法，但藥物的副作用、抗生素的抗藥性，常影響治療與根除胃幽門螺旋桿菌的成功率，因此極需研發非抗生素的替代療法，來預防或治療胃幽門螺旋桿菌的感染。本論文藉由人體和體外試驗探討Lactobacillus paracasei是否具有抑制胃幽門螺旋桿菌生長及改善人體腸道細菌相的保健功效。 在人體試驗部分，總共招募50位已感染胃幽門螺旋桿菌、尚無胃潰瘍症狀，目前無需進行藥物治療的患者參與，每位受試者均參與四階段、為期十一週的交叉實驗：第一階段為一週飲食調整期，接者為四週實驗I期，A組受試者每日早晚各飲用一瓶A受試產品，而B組則每日早晚各飲用一瓶B產品。（A、B產品分別為已上市含Lactobacillus paracasei LCA506活菌原味發酵乳，和不含Lactobacillus paracasei活菌，但其餘成分與前述受試產品相同。）第三階段為兩週排空期，最後為四週實驗II期：A、B兩組交換飲用受試產品。利用碳十三尿素呼氣試驗，以及酵素免疫分析法偵測糞便檢體中之胃幽門桿菌抗原，以評估乳酸菌是否能影響胃幽門桿菌的生長，並觀察受試者的腸道菌相是否獲得改善。結果顯示受試者每日飲用LCA506活菌原味發酵乳四週後，ΔUBT值由42.4 ± 22.5降為34.0 ± 20.3，以paired t-test 分析具統計差異（p < 0.005）；受試者糞便中胃幽門桿菌抗原以酵素免疫法分析，在飲用LCA506活菌原味發酵乳前為1.54 ±1.79，飲用四週後為1.06 ± 1.44，p = 0.007，可明顯抑制胃幽門螺旋桿菌生長。腸道菌相部分結果顯示受試者每日飲用LCA506活菌原味發酵乳後，乳酸桿菌總菌數明顯增加，具統計差異（p < 0.05），而比菲德氏菌總菌數有增加趨勢，具有臨界顯著差異（p = 0.06）。為深入探討Lactobacillus paracasei LCA506抑制胃幽門桿菌的可能機制，再以體外試驗分別從三個面向去探討乳酸菌如何影響胃幽門桿菌，試驗結果顯示，Lactobacillus paracasei具有良好耐酸及耐膽鹽的能力，並能抑制人類胃上皮細胞因胃幽門桿菌感染後所分泌的IL-8，但其培養上清液不具有直接抑制胃幽門桿菌生長之作用。綜和人體和體外試驗結果顯示「LCA506 活菌原味發酵乳」中所含的Lactobacillus paracasei可以降低發炎反應相關激素IL-8的產生，降低受試者體內胃幽門桿菌數，此外也能增加腸道中有益菌(乳酸桿菌)菌數，具有改善人體胃腸功能之保健功效。
並列摘要
Helicobacter pylori is a major cause of peptic ulcer and a risk factor for gastric malignancies. At present, combination therapy consisting of 2 antibiotics and a proton pump inhibitor is regarded as a treatment of choice to eradicate H. pylori infection. However, recently, several studies have concluded that H. pylori eradication rates are reducing, and that this is closely related to its increased resistance to antibiotics. For developing a non-antibiotic alternative therapy to increase the eradication rates of H. pylori, the aim of this study was to explore the impact of Lactobacillus paracasei 506 on the growth of H. pylori by in vitro and in vivo human study. The human experiment was a double-blind randomized placebo- controlled, self-comparing clinical study. Fifty adult volunteers ( positive 13C-urea breath test and serology, but without upper gastrointestinal tract lesions）were recruited into the study and divided into two groups. This 11-week trial comprised an initial lead-in week with no study intervention, a 4-week experimental phase I (either LCA506 fermented milk or placebo, 150 mL/twice/day), a 2-week washout phase, a 4-week experimental phase II (switched to other fermented milk), followed by a final week of washout. H. pylori bacterial loads were determined using the 13C urea breath test and H. pylori stool antigen assay kit, which was performed before and 4 weeks after the start of LCA506 fermented milk or placebo supplementation. Stool samples were also cultured for counting colonies of total anaerobic bacteria, Lactobacillus spp., Bifidobacterium spp., and Clostridium perfringens. After drinking LCA506 fermented milk for 4 weeks, the urease activity of H. pylori decreased from 42.4 ± 22.5 to 34.0 ± 20.3（p < 0.005）. The stool H. pylori antigen quantitaed by ELISA kit decreased from 1.54 ± 1.79 to 1.06 ± 1.44 ( p = 0.007). However, the ΔUBT value of subjects after drinking placebo milk only decreased from 40.1 ± 23.0 to 37.7 ± 22.8 ( no significance ). The colony counts of Lactobacillus spp. in stool sample (after drinking LCA506 fermented milk for 4 weeks) were significantly increased (p < 0.05), and also Bifidobacterium spp. ( p = 0.06 ). For further exploring the possible mechanism of Lactobacillus paracasei 506 on the growth of H. pylori, we investigated the effects of lactobacillus spp. against H. pylori in vitro. L. paracasei showed well tolerance of low pH and bile salts, and could inhibit Helicobacter-induced IL-8 production on AGS cells. But the culture supernatants of L. paracasei could not inhibit the growth of H. pylori directly. These results suggest that supplement with L. paracasei in LCA506 fermented milk may suppress the pathogenicity of H. pylori through the reduction of H. pylori-induced IL-8 production from gastric cells. In addition, it also can improved the ecosystem of the intestinal tract by increasing the amount of Lactobacillus spp. and Bifidobacterium spp..