IMMUNOHISTOCHEMICAL ASSESSMENT OF STEROID-HORMONE RECEPTORS IN TISSUES OF THE ANAL-CANAL - IMPLICATIONS FOR ANAL INCONTINENCE

Background. A prerequisite for a hormonal influence on anal continence in women is the presence of hormone receptors in the tissues of the a nal canal. Using immunohistochemical techniques, we demonstrated and l ocalized estrogen and progesterone receptors (ER, PR) in tissue sectio ns of the anal canal. Methods. Thirty-five specimens of the anorectal region from 21 patients (14 women, seven men) were examined histologic ally for smooth muscle (present in specimens from ten females and in s even males), striated muscle (present in three females and five males) , and perimuscular connective tissue (present in 12 females and seven males). immunostaining for ER and PR was then performed by incubating with primary anti-ER and anti-PR antibody and visualization of specifi c antibody binding by the ABC technique with DAB as chromogen. Results . Positive staining for ER and PR was seen exclusively over cell nucle i. Estrogen receptors were found in the smooth muscle cells of the int ernal sphincter of all females (10/10) and in four of the seven males. Staining for ER was detected in the perimuscular connective tissue of all females (12/12) and in four of the seven males. No specific stain ing for ER or PR was found in the nuclei of striated muscle cells of t he external sphincter in males or females (n = 8). In females, about 5 0% of the ER-positive tissues were also found to be positive for PR. A mongst the male patients, only one exhibited staining for PR, and this was confined to the smooth muscle. Conclusions. Expression of ER is a constitutional feature of the connective tissue and smooth muscle cel ls of the anal continence organ. Estrogen receptors and PR are not det ectable in the striated muscle fibers of the external anal sphincter i n either sex. The presence of ER in the stroma and smooth muscles of t he anal canal suggests that these tissues are targets for estrogen. Th is constitutes a theoretical basis for the beneficial effects of estro gen and progestin replacement on anal continence in postmenopausal wom en.