Distribution of lactoferrin in the normal and inflamed human prostate: An immunohistochemical study

Abstract

A polyclonal rabbit antibody to lactoferrin was used to localize the distribution of lactoferrin within the different zones of the normal human prostate as well as within the inflamed human prostate. Cases of normal central zone, peripheral zone, periurethral glandular tissue, as well as cases in which foci of moderate to severe inflammation, along with varying degrees of inflammation-related atrophy, were studied. In cases with inflammation, the staining pattern of lactoferrin was compared to the staining pattern of prostate-specific antigen. Within the central zone, lactoferrin staining occurred in numerous individual cells peppered throughout the epithelium as well as within multiple intraepithelial lumens (lacunae). These lacunae were often numerous enough to give the central zone epithelium a fenestrated appearance; they were not seen in any of the other regions of the prostate. With the exception of an occasional individual cell or isolated positive gland, normal peripheral zone exhibited very little lactoferrin activity. Staining within the transition zone was similar to that seen in the peripheral zone. Staining within the urethral lining of the epithelium in the periurethral glands showed a distinct pattern of frequent intense staining involving the entire gland; frequent individual positive cells were also often seen. Three patterns of staining were identified in prostatic inflammation. Mild periglandular chronic inflammation produced foci of epithelial lactoferrin positivity that coincided precisely with the areas of inflammation. Severe acute inflammation produced strong staining within luminal secretions while cytoplasmic staining was limited to the luminal surface of the epithelium. Post-inflammatory atrophy showed intense diffuse lactoferrin staining in the scant cytoplasm of the atrophic epithelium. In 12 of the 17 cases of inflammation that were studied, areas of post-inflammatory atrophy or severe inflammation commonly showed absence of prostate specific antigen staining and epithelium that was strongly lactoferrin-positive. Within the normal human prostate, lactoferrin appears to be produced primarily within the epithelium of the central zone, periurethral glands, and lining epithelium of the prostatic urethra. Lactoferrin-filled central zone lacunae appear to be structures unique to the central zone. The distribution of lactoferrin in the periurethral glands and urethral lining epithelium, along with the intense production of lactoferrin in the presence of inflammation, and the preservation of lactoferrin production in severe inflammation or atrophy suggest that lactoferrin may be a key component of the inflammatory response within the human prostate.

Acute inflammatory proteins constitute the organic matrix of prostatic corpora amylacea and calculi in men with prostate cancer

“…4, E and F) (30). Likewise, as has been reported previously, prostate cancer was found to be negative for lactoferrin production ( Fig.…”

Activation of β-catenin in prostate epithelium induces hyperplasias and squamous transdifferentiation

“…High levels of lactotransferrin have been detected in neoplastic cells and differentiated adenocarcinomas of the prostate, but not in undifferentiated carcinomas (Barresi and Tuccari, 1984). Since lactotransferrin levels are increased upon inflammation of the human prostate gland (Reese et al, 1992) and high levels are detected in lymphocytes, it is possible that the expression in prostate tissue upon b-catenin stabilization reflects both hyperplasias and an immune response. It is worth noting that other genes linked to immune cell activity are also activated, including the lymphocyte antigen 6 complex and WM65 k-immunoglobulin (Table 1).…”

Proteases in prostate development, function, and pathology

“…In addition to being the chief source of the 26 kDa protease, it alone secretes plasminogen activator and several caseinoytic activities (Wilson et al, 1993a). The central zone of the human prostate selectively secretes tissue-type activator (Reese et al, 1988) and pepsinogen I1 (Reese et al, 19861, whereas PSA is secreted from both the central and peripheral zones (Reese et al, 1992). The prostatic zone(s) of origin of many of the gelatinolytic and caseinolytic activities in the human is not known, but, like pepsinogen 11, some gelatinolytic activities are secreted by both the prostate and seminal vesicles (Yin et al, 1990).…”