一項刊登在PNAS上的研究揭示了，食用經(jīng)過遺傳改造的嗜酸乳酸桿菌能重置小鼠的可能導致癌癥的免疫應答,，并縮小前癌結腸息肉,。此前對益生腸道微生物嗜酸乳酸桿菌的研究已經(jīng)表明，通過刪除被稱為脂磷壁酸（LTA）的細胞表面分子的基因,，這種細菌可以減少導致小鼠結腸炎的炎癥應答,。
為了研究脂磷壁酸（LTA）是否也是越來越被懷疑促進了腫瘤的過度活躍的炎癥應答的參與因素之一，Mansour Mohamadzadeh及其同事讓有病理性炎癥和前癌結腸息肉的小鼠口服了缺乏脂磷壁酸（LTA）的嗜酸乳酸桿菌,。這組作者說,，這種療法重置了過度活躍的炎癥應答，并且把試驗對象的腸內(nèi)環(huán)境恢復到了健康的平衡態(tài),，因此也就把腸粘膜解放出來,，從而處理結腸息肉并使其退化。
這組作者說,，除了表明消化道微生物群炎癥參與免疫應答,，這些發(fā)現(xiàn)還表明了嗜酸乳酸桿菌可能提供調(diào)控腸內(nèi)免疫、逆轉某些前癌狀態(tài)并預防諸如結腸癌等炎癥驅動的惡性腫瘤,。（生物谷Bioon.com）
doi:10.1073/pnas.1207230109
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Abating colon cancer polyposis by Lactobacillus acidophilus deficient in lipoteichoic acid
Khashayarsha Khazaiea, Mojgan Zadeha,b, Mohammad W. Khana, Praveen Bereb, Fotini Gounaric, Kirsten Dennisa, Nichole R. Blatnera, Jennifer L. Owenb, Todd R. Klaenhammerd,1, and Mansour Mohamadzadeha,b,1
An imbalance of commensal bacteria and their gene products underlies mucosal and, in particular, gastrointestinal inflammation and a predisposition to cancer. Lactobacillus species have received considerable attention as examples of beneficial microbiota. We have reported previously that deletion of the phosphoglycerol transferase gene that is responsible for lipoteichoic acid (LTA) biosynthesis in Lactobacillus acidophilus (NCK2025) rendered this bacterium able to significantly protect mice against induced colitis when delivered orally. Here we report that oral treatment with LTA-deficient NCK2025 normalizes innate and adaptive pathogenic immune responses and causes regression of established colonic polyps. This study reveals the proinflammatory role of LTA and the ability of LTA-deficient L. acidophilus to regulate inflammation and protect against colonic polyposis in a unique mouse model.
