Morphology of the immune cells in the wall of the human uterine tube and their possible impact on reproduction-uterine tube as a possible immune privileged organ.

The uterine tube, as well as other parts of the upper female reproductive system, is immunologically unique in its requirements for tolerance to allogenic sperm and semi-allogenic embryos, yet responds to an array of sexually transmitted pathogens. To understand this dichotomy, there is a need to understand the functional morphology of immune cells in the wall of the uterine tube. Thus, we reviewed scientific literature regarding immune cells and the human uterine tube by using the scientific databases. The human uterine tube has a diverse population of immunocompetent cells representing both the innate and adaptive immune systems. We describe in detail the possible roles of cells of the mononuclear phagocyte system (macrophages and dendritic cells), T and B lymphocytes, natural killer cells, neutrophils and mast cells in association with the reproductive functions of uterine tubes. We are also discussing about the possible "immune privilege" of the uterine tube, as another mechanism to tolerate sperm and embryo without eliciting an inflammatory immune response. In uterine tube is not present an anatomical blood-tissue barrier between antigens and circulation. However, the immune cells of the uterine tube probably represent a type of "immunological barrier," which probably includes the uterine tube among the immunologically privileged organs. Understanding how immune cells in the female reproductive tract play roles in reproduction is essential to understand not only the mechanisms of gamete transport and fertilization as well as embryo transport through the uterine tube, but also in improving results from assisted reproduction.

Decellularization of the human urethra for tissue engineering applications.

Recently, several scaffolds have been introduced for urethral tissue engineering. However, acellular human urethral scaffold harvested from deceased donors may provide significant advantages compared to synthetic, composite, or other biological scaffolds. This study aims to develop the protocol for decellularization of the human urethra that preserves substantial extracellular matrix (ECM) components, which are essential for subsequent recellularization mimicking the natural environment of the native ECM. A total of 12 human urethras were harvested from deceased donors. An equal part of every harvested urethra was used as a control sample for analyses. The protocol design was based on the enzyme-detergent-enzyme method. Trypsin and Triton X-100 were used to remove cells, followed by DNase treatment to remove DNA residues. Subsequently, the specimens were continually rinsed in deionized water for seven days. The efficiency of decellularization was determined by histochemistry, immunohistochemical staining, scanning electron microscopy (SEM), and DNA quantification. Histological analysis confirmed cell removal and preservation of urethral structure after decellularization. The preservation of collagen IV and fibronectin was confirmed by histologic examination and immunohistochemical staining. SEM confirmed the maintenance of the ultrastructural architecture of ECM and fibers. DNA content in decellularized urethra was significantly lower compared to the native sample (P < 0.001), and so the criteria for decellularized tissue were met. Cytotoxicity analysis data showed that the matrix-conditioned medium did not contain soluble toxins and had no significant inhibitory effect on cell proliferation, providing evidence that the decellularized samples are not toxic. This study demonstrates the feasibility of the enzyme-detergent-enzyme-based decellularization protocol for removing cellular components and maintaining urethral ECM and its ultrastructure. Moreover, obtained results provide solid ground for recellularization and urethral tissue engineering, which will follow.

Traditional and contemporary views on the functional morphology of the fallopian tubes and their importance for gynecological practice.

The uterine tube, belonging to the female internal reproductive organs, is the only tubular organ in the human body that has, under physiological conditions, a transport function occurring in two opposite directions. It transports the picked-up oocyte released during ovulation and early embryo towards the uterine cavity. At the same time, it can transport spermatozoa towards the abdominal opening of the fallopian tube. Moreover, the uterine tube has many other vital functions as sperm selection (one of the crucial factors preventing polyspermy) and the production of tubal fluid. This unique secretion is essential not only for the process of fertilization but also for sperm activation and the nourishment of the early embryo during its transport into the uterine cavity. The first part of our review is focused on the historical introduction to the topic in which the reader will become familiar with the views and understanding of these peculiar organs by famous anatomists of the 16th and 17th centuries, namely Gabriele Falloppio and Renier de Graaf. The following section will cover the overview of the latest anatomical, embryological, and histological knowledge, which are also crucial for a better understanding of pathological processes affecting the fallopian tube, such as tubal infertility or tubal pregnancy. Interestingly, recent years have been very fruitful regarding uterine tube morphology, e. g. the discovery of an unique mechanism of lymphatic flow within the uterine tube mucosa, the first description of immunologically-active intraepithelial suppressor T-lymphocytes, or the observation of pacemaker cell population - telocytes - in the muscle layer.