INVESTIGATIVE UROLOGY

Compositional changes of collagen and glycosaminoglycans in the tunica albuginea and corpus cavernosum from the human penis during the fetal and postnatal periods
Bastos AL, Sampaio FJ, Cardoso LE
Urogenital Research Unit, State University of Rio de Janeiro, Rio de Janeiro, Brazil
J Urol. 2005; 173: 1039-43

• Purpose: We investigated the composition of collagen and glycosaminoglycans (GAGs) in the corpus cavernosum (CC) and tunica albuginea (TA) of normal human penises.
• Materials and Methods: Penises were obtained from a 6-month-old child (group 1), a 2-year-old child (group 2), 18 to 34-year-old adults (group 3), 37 to 53-year-old adults (group 4) and 22 fetuses at 17.2 to 33.3 menstrual weeks (group 5). Total GAG and collagen concentrations were expressed per mg dry tissue and proportions of GAG species were determined by agarose electrophoresis and ion exchange chromatography.
• Results: The GAG concentration in group 1 CC and TA was 1.32 and 0.52 microg/mg, respectively, and thereafter it increased noticeably. TA collagen concentration followed a similar pattern. TA had more collagen than CC in groups 3 (mean +/- SD 93.41 +/- 6.17 vs 53.77 +/- 11.18 microg/mg, p <0.001) and 4 (89.94 +/- 5.53 vs 55.39 +/- 5.89 microg/mg, p <0.01). In these groups TA and CC differed markedly in the proportion of hyaluronan, heparan sulfate and dermatan sulfate. In TA group 4 had slightly less hyaluronan and more chondroitin sulfate than group 3 but in CC the GAG proportions were similar. Collagen content in the whole fetal penis correlated with gestational age (r = 0.78, p <0.001).
• Conclusions: Collagen and the GAG concentration in the human penis undergo extensive modifications during development and shortly after birth but from ages 2 to approximately 46 years changes are limited to the proportion of GAG species in TA from older individuals. Reflecting diverse biomechanical roles, the extracellular matrix of CC and TA are markedly different.
  
  
• Editorial Comment
  It is well known that depending on function and biochemechical properties, extracellular matrix (ECM) differs noticeably among tissues. The present paper demonstrated that proportions of hyaluronan, heparan sulfate and dermatan sulfate are different in corpus cavernosum and tunica albuginea of human penis, indicating the different properties of these structures. In terms of tissue engineering, their compositions should be taken into account when choosing the ideal material for surgical reconstruction of penile tissues
  Interestingly, this paper demonstrates that the most significant ECM developmental changes in the penis occur between 17 and 33 weeks of gestation, which were reflect by important increase in collagen concentrations. Surprisingly, collagen and glycosaminoglycans concentrations in the corpus cavernosum and tunica albuginea remain unchanged from ages 2 to 36-53 years, suggesting that the hormonal alterations that markedly affect penile morphology and function with the onset of adolescence have little or no effect on the overall collagen and GAG composition of penile erectile tissues.

Dr. Francisco J.B. Sampaio
Full-Professor and Chair, Urogenital Research Unit
State University of Rio de Janeiro
Rio de Janeiro, Brazil