Orsola A, Estrada CR, Nguyen HT, Retik AB, Freeman MR, Peters CA, Adam RM. Growth and stretch response of human exstrophy bladder smooth muscle cells: molecular evidence of normal intrinsic function.
BJU Int 2005;
95:144-8. [PMID:
15638913 DOI:
10.1111/j.1464-410x.2004.05267.x]
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Abstract
OBJECTIVE
To establish primary cultures of smooth muscle cells (SMC) from human exstrophic bladders (E-SMC), and determine their in vitro growth dynamics and responses to mechanical stretch.
MATERIALS AND METHODS
Primary cultures of E-SMC from three patients were established from exstrophic bladder tissue using an explant method. Growth dynamics were assessed using tetrazolium-dye uptake. The DNA synthesis rate in response to cyclic stretch-relaxation was determined with thymidine-incorporation assays. Expression of the SMC mitogen heparin-binding epidermal growth factor-like growth factor (HB-EGF) mRNA in response to mechanical stretch was determined using semiquantitative reverse transcription-polymerase chain reaction.
RESULTS
The approximate doubling time of the E-SMC grown in the presence of serum was 4 days, consistent with growth rates of SMC reported previously. E-SMC exposed to stretch had greater DNA synthesis, albeit to a lesser extent than previously seen with non-exstrophic SMC. The expression of HB-EGF was also increased in cells exposed to mechanical stimuli, consistent with our previous finding of stretch-regulated HB-EGF gene expression in bladder SMC.
CONCLUSIONS
E-SMC had growth characteristics similar to those previously reported in non-exstrophic cells. E-SMC also had stretch-induced expression of HB-EGF mRNA. These observations provide evidence that despite development in an abnormal defunctionalized state, E-SMC retain the potential for normal growth, and may modulate this response through mechanisms similar to those operating in normal bladder SMC.
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