Pitted pattern in the human epididymis

Seminal fluid metabolome and epididymal changes after antibiotic treatment in mice

Paternal environment can induce detrimental developmental origins of health and disease (DOHaD) effects in resulting offspring and even future descendants. Such paternal-induced DOHaD effects might originate from alterations in a possible seminal fluid microbiome (SFM) and composite metabolome. Seminal vesicles secrete a slightly basic product enriched with fructose and other carbohydrates, providing an ideal habitat for microorganisms. Past studies confirm the existence of a SFM that is influenced by genetic and nutritional status. Herein, we sought to determine whether treatment of male mice with a combination of antibiotics designed to target SFM induces metabolic alterations in seminal vesicle gland secretions (seminal fluid) and histopathological changes in testes and epididymides. Adult (10- to 12-week-old) National Institutes of Health (NIH) Swiss males (n = 10 per group) were treated with Clindamycin 0.06 mg/kg day, Unasyn (ampicillin/sulbactam) 40 mg/kg day and Baytril (enrofloxacin) 50 mg/kg day designed to target the primary bacteria within the SFM or saline vehicle alone. Fourteen-day antibiotic treatment of males induced metabolomic changes in seminal vesicles with inosine, xanthine and l-glutamic acid decreased but d-fructose increased in glandular secretions. While spermatogenesis was not affected in treated males, increased number of epididymal tubules showed cribriform growth in this group (7 antibiotic-treated males: 3 saline control males; P = 0.01). Antibiotic-treated males showed more severe cribriform cysts. Current findings suggest antibiotic treatment of male mice results in seminal fluid metabolome and epididymal histopathological alterations. It remains to be determined whether such changes compromise male reproductive function or lead to DOHaD effects in resulting offspring.

Why are epididymal tumours so rare?

Epididymal tumour incidence is at most 0.03% of all male cancers. It is an enigma why the human epididymis does not often succumb to cancer, when it expresses markers of stem and cancer cells, and constitutively expresses oncogenes, pro-proliferative and pro-angiogenic factors that allow tumour cells to escape immunosurveillance in cancer-prone tissues. The privileged position of the human epididymis in evading tumourigenicity is reflected in transgenic mouse models in which induction of tumours in other organs is not accompanied by epididymal neoplasia. The epididymis appears to: (i) prevent tumour initiation (it probably lacks stem cells and has strong anti-oxidative mechanisms, active tumour suppressors and inactive oncogene products); (ii) foster tumour monitoring and destruction (by strong immuno-surveillance and -eradication, and cellular senescence); (iii) avert proliferation and angiogenesis (with persistent tight junctions, the presence of anti-angiogenic factors and misplaced pro-angiogenic factors), which together (iv) promote dormancy and restrict dividing cells to hyperplasia. Epididymal cells may be rendered non-responsive to oncogenic stimuli by the constitutive expression of factors generally inducible in tumours, and resistant to the normal epididymal environment, which mimics that of a tumour niche promoting tumour growth. The threshold for tumour initiation may thus be higher in the epididymis than in other organs. Several anti-tumour mechanisms are those that maintain spermatozoa quiescent and immunologically silent, so the low incidence of cancer in the epididymis may be a consequence of its role in sperm maturation and storage. Understanding these mechanisms may throw light on cancer prevention and therapy in general.

Microlithiasis of the epididymis and the rete testis

Testicular microlithiasis is a well-defined clinical and pathologic entity easily diagnosed through testicular echography; however, its association with cancer and infertility is now under debate. Many efforts have been done in recent years to clarify the spectrum of lesions observed in testicular microlithiasis, but no published data as to the existence of a possible microlithiasis of the epididymis and the rete testis have been found. We have observed microlithiasis of the epididymis and the rete testis in surgical (8 epididymis and 6 testis) and autopsy specimens (12 cases). In decreased order of frequency, microliths of the proximal spermatic way were seen in rete testis, epididymal duct, and efferent ducts. Intraluminal, subepithelial, and interstitial microliths were localized along these segments of the spermatic way. Subepithelial microliths were the most frequently found. A granulomatous reaction around the interstitial epididymal microliths, mimicking malacoplakia, was observed in 1 case. The differential diagnosis of microliths includes corpora amilacea, Michaelis-Gutmann bodies, calcium deposits, hyaline globules, and parasites, like the giant kidney worm Dioctophyme renale. In infants and young adults, microlithiasis of the epididymis and the rete testis is frequently associated with alterations in the development of the proximal spermatic way. In elderly adults, it is related to ischemia and obstruction of the spermatic way.

Histological and immunohistochemical study of the cat epididymis

A histological and immunohistochemical study of the epididymis of 21 cats which ranged from 7 to 8 months to 2 years of age was made. Five different cell types were observed in the feline epididymis: principal and basal cells, which were the most numerous, apical and narrow, PAS positive cells, which were scarce, and migratory cells, consisting of lymphocytes and macrophages. Four morphologically distinct areas of the cat epididymis were identified. Region I displayed a stellate lumen and the principal cells were tall and presented long and irregular stereocilia. In region II, the lumen was oval and the principal cells were shorter than in the initial area. Region III displayed characteristics similar to those of region I; the principal difference was the presence of short and regular stereocilia on the surface of the principal cells. In region IV the lumen was very spacious and the epithelium shorter than in the other regions. In regions I, II, and III intraepithelial cavities were observed. With regard to the immunohistochemical results, the basal cells displayed medium immunoreactivity with vimentin. Due to its anti-desmin reactivity, the muscle wall which surrounds the epididymis was seen to become progressively thicker as it nears the tail. Broad-spectrum anti-cytokeratin serum produced intense immunostaining in the basal, apical and narrow, PAS positive cells; the principal cells of region IV also displayed a strong immunoreactivity.

Sequential histology of the adult chimpanzee epididymis

The chimpanzee epididymis consists of three gross anatomical regions: caput (Cp), corpus (Cr), and cauda (Cd). During epididymal transit, chimpanzee sperm undergo maturational changes (affecting motility, capacitation, and the acrosome reaction), which enable fertilization. Elucidation of the sequential histology of the chimpanzee epididymis is preliminary to determining the role of each region of epididymal duct in the process of sperm maturation. We report the histology, in the adult male chimpanzee, of sequential segments of epididymis from the proximal efferent ductules through the Cp, Cr, and Cd regions of the epididymis proper to the proximal ductus deferens. These data illustrate the gross architecture of the tissue and reveal the histology characteristic of the diverse epithelia composing the epididymal ducts at each level. The tubules composing the epididymis of the adult male chimpanzee present at least 16 histologically-distinct epithelia and their transitional forms. Such diversity of epithelia suggests a corresponding diversity of function. Although there are some clear differences, the histological appearance of the ducts, and of the component epithelia of the chimpanzee epididymis, is remarkably similar to that reported for the human.