抗菌肽人β防御素3对肺炎克雷伯菌临床菌株的抑制作用研究

目的分析抗菌肽人β防御素3(hBD3)对肺炎克雷伯菌临床分离株的抑菌作用。方法合成抗菌肽hBD3,分别通过最低抑菌浓度(MIC)检测、直接杀菌试验、重要功能基因检测分析其对20株临床分离的肺炎克雷伯菌的直接抑制作用;并将其与阿莫西林、头孢他啶、环丙沙星联合应用,观察其对抗菌药物50%最低抑菌浓度(MIC50)和90%最低抑菌浓度(MIC90)的影响。结果hBD3对20株肺炎克雷伯菌的MIC为(22.3±6.6)μg/mL;在浓度达到8μg/mL时即有明显的杀菌作用。hBD3可上调ompC基因表达,下调yojL基因表达。在联用5μg/mL hBD3后,头孢他啶、环丙沙星的MIC50和MIC90值均明显降低,而阿莫西林的MIC50和MIC90值无明显变化。结论抗菌肽hBD3对肺炎克雷伯菌有明显的抑制作用,可望与抗菌药物联用治疗肺炎克雷伯菌感染。     

人β防御素2评价肺部疾病临床研究进展

人β防御素2(HBD2)是一类在肺部上皮呈可诱导性表达的抗菌肽。由于其抗菌活性和免疫调节功能,HBD2在肺部感染和炎症性疾病中发挥重要作用,可能参与肺部疾病的发生、发展。故检测肺组织或体液中HBD2的水平对临床上指导肺部疾病的诊疗有积极的作用。该文就HBD2的结构、功能及其作为一个炎性因子在评价肺部疾病中的临床应用进展予以综述。     

Paneth cells and necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a common and devastating disease of premature infants. Immaturity of the innate immune system of the gut is central to the pathogenesis of NEC. Recent studies suggest a key role for Paneth cells in this disease. Addressing basic questions on the development and function of immature Paneth cells may shed light on the puzzling pathophysiology of NEC. Current animal models of NEC are limited in their capacity to answer these questions.     

防御素与肺炎症性疾病

防御素是富含半胱氨酸，带正电的小分子抗微生物肽，具有广谱的抗微生物活性，包括细菌，真菌和一些包膜病毒，在肺的固有免疫中起重要作用。防御素也可以起到趋化因子的作用，这突出了防御素在宿主免疫和炎症反应中的重要作用。防御素或组成性表达或被细菌和炎症介质所诱导。防御素功能的改变可能会导致疾病。     

人防御素5研究进展

目的　探讨人防御素 5 (humandefensin 5 ,HD 5 )的分子结构、抗菌活性、基因表达等特点 ,展望HD 5作为抗肠源性感染新药的开发前景。方法　采用文献回顾的方法对有关HD 5研究资料进行综合比较和综述。结果　HD 5是一种不含糖链的碱性阳离子多肽 ,相对分子质量为 ( 3～ 5 )× 10 3 ,成熟肽由 32个氨基酸残基组成 ,富含精氨酸、半胱氨酸 ;分子内含有 3对由半胱氨酸形成的二硫键 ,并以此行使其对革兰氏阳性菌、革兰氏阴性菌、真菌、螺旋体、原生动物、有包膜病毒等的抗菌功能。HD 5的编码基因DEFA5位于第 8条染色体P2 1 pter区 ,全长4 4 9bp。其中 1～ 4 0为 5′端非翻译区 ,4 1～ 97为信号肽序列 ,98～ 2 2 6编码HD 5前片段 ,2 2 7～ 32 2为HD 5成熟肽编码序列 ,PolyA序列位于 4 33～ 4 38。 结论　HD 5是一种广谱、高效、不产生耐药性的内源性抗微生物小分子肽 ,如能解决其大量生产的难点 ,则可望成为新型抗肠源性感染新药     

支气管哮喘与急性呼吸道感染患儿血浆β防御素3水平的对照研究

目的β防御素3(HBD3)除了具有天然免疫功能,还发挥调节后天适应性免疫的作用。本研究拟通过支气管哮喘患儿、急性上呼吸道感染患儿及正常儿血浆HBD3浓度的比较,探讨HBD3在哮喘发病中的作用。方法研究对象选择2009年4月到12月在哈尔滨医科大学附属第一医院儿科就诊病例共81例,其中哮喘组21例,为急性发作期支气管哮喘患儿,感染组29例,为急性上呼吸道感染患儿,正常对照组31例,为健康体检儿。采用酶联免疫吸附试验(ELISA)法进行血浆HBD3水平测定。同时测定血嗜酸性粒细胞总数和白细胞数,9例哮喘儿测定了血清IgE浓度。结果血浆HBD3浓度正常儿为(8.028±1.078)μg/ml,哮喘患儿(12.212±1.124)μg/ml感染患儿(8.976±1.110)μg/ml,哮喘患儿与急性呼吸道感染及正常儿3组总体比较,血浆HBD3浓度明显升高,差异有显著性(F=4.448,P<0.05);哮喘组与正常组比较,差异显著,P<0.01;哮喘组与感染组比较,差异有显著性P<0.05;感染组与正常组比较,差异无显著性P>0.05;同时发现血浆HBD3水平与血清总IgE,血嗜酸性粒细胞及白细胞水平无显著相关性。结论支气管哮喘发作时HBD3表达升高,HBD3可能是超越感染之外,参与哮喘发病的独立因素。HBD3是否始动因素尚待进一步探索。     

Expression of antimicrobial peptides in cutaneous infections after skin surgery

Summary Background Increasing numbers of antibiotics have lost efficiency because of bacterial resistance. The consequences can be severe when surgical wounds become infected during postoperative care. Natural peptide antibiotics, the so‐called host defence peptides (HDPs), have been investigated since the 1990s in a search for alternative treatment strategies. HDPs build up a protection shield against pathological microorganisms, especially in human epithelium. The use of HDPs is currently being discussed as a new antimicrobial therapeutic strategy. Accordingly, a profound knowledge of the quantitative relationships of the effectors is essential. Objectives To evaluate differences in HDP expression between postoperatively inflamed and healthy epithelium. Methods Expression profiles of the genes encoding HDP human β‐defensin (hBD)‐1 (DEFB1, previously known as HBD‐1), hBD‐2 (DEFB4A, previously known as HBD‐2), hBD‐3 (DEFB103A, previously known as HBD‐3) and psoriasin (S100A7) were assessed in samples of surgical wound healing disorders (n = 27) and healthy epithelium (n = 16) by using real‐time polymerase chain reaction. Immunohistochemical staining was performed in the same samples. Results A significant overexpression of DEFB4A (P < 0·001), DEFB103A (P = 0·001) and S100A7 (P < 0·001) was found in cutaneous surgical site infections. Immunohistochemistry revealed intensely elevated protein levels of psoriasin in infected wounds, and differences in distribution with respect to the epithelial layers. Conclusions The study demonstrates upregulated mRNA expression and protein levels of HDPs in postoperatively inflamed epithelium. The results may be a starting point for novel pharmacological treatments.