Elastin metabolism in pelvic tissues: is it modulated by reproductive hormones?
OBJECTIVE
The purpose of this study was to investigate the effect of relaxin on extracellular matrix protein expression in pelvic fibroblasts that were cultured from women with stress urinary incontinence compared with asymptomatic control subjects.


METHODS
Periurethral vaginal wall fibroblasts from premenopausal women with stress urinary incontinence and continent women (in both the proliferative and secretory phase of the menstrual cycle) were stimulated with increasing concentrations of relaxin (0-500 ng/mL). The supernatant was sampled for matrix metalloproteinase-2 and -9 by zymography. Tissue inhibitors of metalloproteinase-1 and -2 and alpha-1 antitrypsin were evaluated with Western blot. Total elastase activity was measured by generation of free amino groups from succinylated elastin. Increasing concentrations of alpha-1 antitrypsin were added to cell lysate to evaluate total elastase activity inhibition.


RESULTS
Proliferative-phase stress urinary incontinence fibroblasts demonstrated an increase in matrix metalloproteinase-2 and no change in matrix metalloproteinase-9 and tissue inhibitors of metalloproteinase-1 and -2 expressions with increasing relaxin concentrations. Cells from control subjects showed increased expression of matrix metalloproteinase-2 and -9, but no change in tissue inhibitors of metalloproteinases. Secretory-phase stress urinary incontinence fibroblasts showed no response in matrix metalloproteinase or tissue inhibitors of metalloproteinase expressions with relaxin stimulation. Secretory-phase control fibroblasts reacted by increasing matrix metalloproteinase-2 and -9 and tissue inhibitors of metalloproteinase-2. With respect to total elastase activity and alpha-1 antitrypsin expression, increasing doses of relaxin appear to increase elastolytic activity in stress urinary incontinence cells by decreasing the expression of alpha-1 antitrypsin in proliferative phase cells or increasing the total elastase activity in secretory phase cells. Fibroblast total elastase activity was inhibited by increasing concentrations of alpha-1 antitrypsin.


CONCLUSIONS
Elastase activity appears to be increased in relaxin-stimulated stress urinary incontinence fibroblasts by either decreased inhibitor (alpha-1 antitrypsin) production or increased elastase activity.
Chen
Bertha
B
Department of Obstetrics and Gynecology, Stanford University School of Medicine, Calif 94305-5317, USA. bchen@stanford.edu
Wen
Yan
Y
Yu
Xiaoyun
X
Polan
Mary Lake
ML
D000328:Adult; D016022:Case-Control Studies; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004549:Elastin / Q000378:metabolism*; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005498:Follicular Phase; D006801:Humans; D019272:Leukocyte Elastase / Q000378:metabolism; D008183:Luteal Phase; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D012065:Relaxin / Q000008:administration & dosage / Q000494:pharmacology*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D014550:Urinary Incontinence, Stress / Q000378:metabolism* / Q000473:pathology; D014621:Vagina / Q000378:metabolism* / Q000473:pathology; D000515:alpha 1-Antitrypsin / Q000378:metabolism
D000515:alpha 1-Antitrypsin; D019716:Tissue Inhibitor of Metalloproteinase-2; D012065:Relaxin; D004549:Elastin; D019272:Leukocyte Elastase; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9