The pathogenesis of benign prostatic hyperplasia: a proposed hypothesis and critical evaluation

Proteomic analysis of patient tissue reveals PSA protein in the stroma of benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) is an age-related disease frequently associated with lower urinary tract symptoms (LUTS) that involves hyperplasia of both epithelial and stromal cells. Stromal fibrosis is a distinctive feature of BPH, but the exact mechanisms underlying this phenomenon are poorly understood.

METHODS

In the current study, proteomics analyses were utilized to identify proteins altered in the BPH stromal compartment from patients with symptomatic BPH. Stromal cells were isolated from histological nodules of BPH by laser capture microdissection (LCM) and subjected to liquid chromatography/mass spectrometry.

RESULTS

Proteins identified included several stromal-specific proteins involved in extracellular matrix (ECM) remodeling, focal adhesion, and cellular junctions. Additionally, the proteomics array identified the presence of luminal epithelial secretory protein PSA. Immunostaining, ELISA, and in situ hybridization analyses of BPH tissues verified the presence of PSA protein but absence of PSA mRNA in the stromal compartment. E-cadherin was down-regulated in BPH epithelial cells compared to normal adjacent tissues, suggesting that alteration of cellular junctions could contribute to the presence of luminal epithelial secreted proteins PSA and KLK2 in the stromal compartment.

CONCLUSIONS

The above findings suggest that the presence of secreted proteins PSA and KLK2 from prostate luminal epithelial cells in BPH stroma is a hallmark of BPH nodules, which could in part be due to alterations in cellular junction proteins and/or increased epithelial barrier permeability. Elucidating the cause and consequence of these secreted proteins in the stromal compartment of BPH may lead to new understanding of BPH pathogenesis as well as approaches to prevent and/or treat this common disease.

Serum sex steroids, gonadotrophins and sex hormone-binding globulin in prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) develops in elderly males when serum androgens are relatively lower than in healthy younger males, but it is not well understood whether and how sex steroids are altered in prostatic hyperplasia. It is also uncertain whether there is any change in sex steroid levels in males older than 40 years of age. The use of androgens in elderly males is often discouraged because of the probable worsening effect of androgens on prostatism. This study aimed to determine the relationship between prostatic hyperplasia and sex steroid levels and whether there is any significant change in these hormones after the age of 40 years.

SUBJECTS AND METHODS

We studied healthy males of age >or=40 years with (n=92) or without (n=93) clinical prostatic hyperplasia. Serum testosterone, estradiol, gonadotrophins and sex hormone-binding globulin (SHBG) were compared. The hormones and SHBG were also correlated with age.

RESULTS

No significant difference was found in any hormone in cases with prostatic hyperplasia as compared with the controls. There was no significant age-related change in any hormone except estradiol where as a negative correlation (P<.003) with age was found.

CONCLUSIONS

Serum sex steroids and SHBG remained unchanged in symptomatic prostatic hyperplasia and except for estradiol there was no significant age-related change in serum testosterone, gonadotrophins and SHBG in healthy males after the fourth decade. More studies are needed to confirm the age-related decline of estrogens in males.