New insights into epididymal biology and function

Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, 79430, USA.
Human Reproduction Update (Impact Factor: 10.17). 02/2009; 15(2):213-27. DOI: 10.1093/humupd/dmn055
Source: PubMed


The epididymis performs an important role in the maturation of spermatozoa including their acquisition of progressive motility and fertilizing ability. However, the molecular mechanisms that govern these maturational events are still poorly defined. This review focuses on recent progress in our understanding of epididymal function including its development, role of the luminal microenvironment in sperm maturation, regulation and novel mechanisms the epididymis utilizes to carry out some of its functions.
A systematic search of Pubmed was carried out using the search term 'epididymis'. Articles that were published in the English language until the end of August 2008 and that focused on the specific topics described above were included. Additional papers cited in the primary reference were also included.
While the majority of these findings were the result of studies in animal models, recent studies in the human epididymis are also presented including gene profiling studies to examine regionalized expression in normal epididymides as well as in those from vasectomized patients.
Significant progress has been made in our understanding of epididymal function providing new insights that ultimately could improve human health. The data also indicate that the human epididymis plays an important role in sperm maturation but has unique properties compared with animal models.

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    • "This study is the first work showing the innate immune responses to UPEC infection in EECs. The epididymal epithelium is composed of mainly principal and basal cells, as well as minor apical and narrow cells[44]. We showed that primary EECs mainly contained principal and basal cells. "
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    ABSTRACT: Uropathogenic E. coli (UPEC) may cause epididymitis and impair male fertility. The mechanisms underlying the innate immune responses to UPEC infection in the epididymis are not fully understood. This study showed that UPEC induced innate immune responses in mouse epididymal epithelial cells (EECs) through the activation of Toll-like receptor (TLR)4 and TLR5. UPEC infection significantly induced the expression of proinflammatory cytokines, including tumor necrosis factor alpha, interleukin 6, and monocyte chemoattractant protein 1, in EECs through the activation of nuclear factor kappa B. Moreover, UPEC induced the production of type 1 interferons by EECs through the activation of interferon regulatory factor 3. The UPEC-induced innate immune responses were significantly reduced in EECs of Tlr4 or Tlr5 knockout mice. The innate immune responses were further reduced in Tlr4 and Tlr5 double knockout EECs. Furthermore, we demonstrated that TLR4 and TLR5 cooperatively initiated the epididymal innate immune responses to UPEC infection in vivo. The results provide novel insights into the mechanisms underlying the epididymal innate immune responses to UPEC infection.
    Preview · Article · Jan 2016 · Biology of Reproduction
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    • "Male fertility can be reduced in many ways, but it has been estimated that for about 50% of cases the cause is not known [1]. Post-testicular defects may be important as the spermatozoon is not a fully mature cell after production in the male gonad and, post-testicular maturation events are necessary for it to be able to fulfill its mission, moving to meet, recognize and fertilize the oocyte23456. These events start in the epididymis, the first organ that sperm cells have to go through when they leave the testis. "
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    ABSTRACT: After its production in the testis, a spermatozoon has to undergo post-testicular maturation steps to become fully motile and fertile. The first step is epididymal maturation during which immature spermatozoa are transformed into biochemically mature cells ready to proceed to the next step, capacitation, a physiological process occurring in the female genital tract. The biochemical transformations include modification of sperm lipid composition during epididymal transit, with significant changes in fatty acids, phospholipids and sterols between the caput and the cauda epididymal spermatozoa. Although quantitative aspects of these changes are well documented for several mammalian species, molecular mechanisms governing these steps are poorly understood. Transgenic male mice invalidated for the two liver X receptors (LXRalpha and LXRbeta, nuclear oxysterol receptors regulating cholesterol and lipid metabolism) become sterile when aging, showing an epididymal phenotype. We used single knockout model mice to characterize the role of each LXR isoform during sperm maturation in the epididymis. We show here that although a certain redundancy exists in the functions of the two LXR isoforms, some physiological processes are more under the influence of only one of them. In both cases, aging males showed slight subfertility, associated with dyslipidemia, emphasizing the importance of lipid metabolism in relation with male fertility.
    Full-text · Article · Jan 2016 · Biology of Reproduction
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    • "Pematangan spermatozoa di dalam epididimis manusia juga terjadi lebih cepat sehingga penyimpanan spermatozoa tidak membutuhkan waktu yang lebih lama. Selain itu, bila dibandingkan dengan spesies lain, proses pematangan spermatozoa manusia relatif lebih sederhana (Cornwall, 2009). Secara fungsional, fungsi epididimis manusia sama dengan spesies mamalia lainnya. "

    Full-text · Article · Nov 2015
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