. 2014 Dec 31;4(2):e979103. doi: 10.4161/21565562.2014.979103

Table 2.

Potential mechanisms for inducing occlusions in the head of the epididymis

Cause	Potential Mechanisms^a	References
Fluid resorption	Increase in the rate of Na+ uptake at the lumen; upregulate endothelin-1 or ET(A); increase in ESR1 expression	^126,¹³⁶^,¹⁴⁹^,^166-168^,^196,²²⁸
Microtubule disruption	Indirect effect on fluid resorption; disruption of epithelial recycle of apical vesicles and membrane proteins associated with ions and water transport	^136,¹⁴²^,^144-146^,¹⁴⁹^,^229-235
Inflammation	Inhibition of immune tolerance; extravasation of luminal germ cells; influx of macrophages and neutrophils; stretching of ductal epithelium	^2,¹⁴⁷^,^171,²³⁶^,²³⁷
Leakage of fluid	Damage to the tight junctions of the vascular endothelium; leakage at the efferent ductal epithelium	^124,¹⁶¹^,^{173, 174}^,²⁰⁹
Ischemia	Inhibition of blood flow; dilation of veins; arterial occlusions; also damage to the endothelium	^{151, 152}^,^156,¹⁷³^,^174,²⁰⁶^,^{226, 227}^,²³⁸
Sperm stasis	Inhibition of peritubular smooth muscle tone, either directly or indirectly through inhibition of sympathetic nerves	^147,²³⁹^,²⁴⁰
Developmental malformations	Abnormal growth that blocks the lumen	^{123, 124}^,^{177, 178}^,^{194, 195}

^aThese are suggested mechanisms based on collective data and not necessarily direct association with efferent ductules and epididymis.