Page 96 - Slipped Capital Femoral Epiphysis Pathogenetic and Clinical aspects

Chapter 5
We observed increased expression in 9 out of 18 cases, making a preslippage (inflammatory) process, if it occurs, not a prerequisite for SCFE. Moreover, CD34 expression was also observed 3 of the 10 control biopsies.
Expressions of eight hormone receptors were comparable in SCFE and control cases. Since SCFE occurs during periods of altered hormone homeostasis (during puberty or in children with endocrine disease), our finding observation either suggests perturbation in signaling without altered expression (not excluding alterations in intracellular events) or a limiting role for these signals in SCFE. In our study, we observed ER-β receptor expression in osteocyte and chondrocyte nuclei, but we did not see a difference between SCFE cases and controls. In addition, we could not detect expression of either ER-α or AR in either group despite another study that reported expression in human physis [16]. Differences between our study and abovementioned study may be related to tissue specific differences in antibody (ER-6F11 vs SP1 clone) [6]. Leptin may have a direct effect on the physis through LR by increasing the width of the proliferative zone in a dose-dependent manner [21] but in our series LR expression was were very low and showed no difference in either SCFE cases or controls. A similar pattern was observed for and TR α, while TR- β receptor was not detected in either group. The expression of insulin like growth factor receptor (IGFR1) and growth hormone receptor expression was clearly observed (in cytoplasm of chondrocytes and osteocytes) but, again, showed no difference between SCFE and controls. Both growth hormone (GH) and insulin- like growth factor (IGF1) axes are reportedly active in physis growth regulation [12, 19], but we did not observe altered expression of either receptor, making a crucial role for the hormones less likely as is stated in the literature [4, 14].
Our small series has limitations. It is a crosssectional, observational study with limitations for procuring age-sex matched biopsies from normal physes or taking biopsies from controlateral sides in patients [17]. So, we cannot exclude the possibility that more proper controls, i.e. from children in a similar phase of puberty and similar physes sites, may have showed different pattern from our current controls. In other words, our lack of differential patterns of hormonal receptors does not rule out that the slip may be due to a transient imbalance of hormonal changes during puberty. In second limitation of our study may have been the timing of the biopsies: we could only take biopsies during the fixation of the femoral head which was usually 3 to 6 months or even longer after the initial slippage, giving a more restricted picture of the actual event of slippage. Finally, although the SCFE-
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