Sex differences have been found in the incidence and progression of inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease. The reported differences in observational studies are controversial, and the effects of sex hormones on the pathogenesis of IBD are not clear. The aim of this study was to analyze sex differences in the progression of experimentally induced colitis. Experimental colitis was induced in adult mice by adding 2% dextran sodium sulfate (DSS) into drinking water. Male and female mice were used as intact, gonadectomized, and supplemented with either estradiol or testosterone. In comparison to males, female mice with induced colitis had significantly longer colon (p < 0.05), lower decrease in body weight (p < 0.001), and lower stool consistency score (p < 0.05). Histopathological analysis showed less inflammatory infiltrates (p < 0.001) and crypt damage (p < 0.001) in female mice. Female mice with colitis had also lower concentration of TNF-α in colon homogenates (p < 0.01). Supplementation with estradiol in ovariectomized mice ameliorated the severity of colitis. Female mice are partially protected against chemically induced colitis. This protection seems to be mediated by estradiol.

Antimicrobial peptides (AMP) are a heterogeneous group of molecules involved in the nonspecific immune responses of a variety of organisms ranging from prokaryotes to mammals, including humans. AMP have various physical and biological properties, yet the most common feature is their antimicrobial effect. The majority of AMP disrupt the integrity of microbial cells by 1 of 3 known mechanisms--the barrel-stave pore model, the thoroidal pore model, or the carpet model. Results of growing numbers of descriptive and experimental studies show that altered expression of AMP in various tissues is important in the pathogenesis of several gastrointestinal, respiratory, and other diseases. We discuss novel approaches and strategies to further improve the promising future of therapeutic applications of AMP. The spread of antibiotic resistance increases the importance of developing a clinical role for AMP.

Recent advances in gene therapy can be attributed to improvements of gene delivery vectors. New viral and nonviral transport vehicles that considerably increase the efficiency of transfection have been prepared. However, these vectors still have many disadvantages that are difficult to overcome, thus, a new approach is needed. The approach of bacterial delivery could in the future be important for gene therapy applications. In this article we try to summarize the most important modifications that are used for the preparation of applied strains, difficulties that are related with bacterial gene delivery and the current use of bactofection in animal experiments and clinical trials. Important differences to the alternative gene therapy (AGT) are discussed. AGT resembles bacteria-mediated protein delivery, as the therapeutical proteins are produced not by host cells but by the bacteria in situ and the expression can be regulated exogenously. Although the procedure of bacterial gene delivery is far from being definitely solved, bactofection remains a promising technique for transfection in human gene therapy.