Abstract: PD31-10
Sources of Funding: None

Introduction

About a third of Peyronie&[prime]s Disease (PD) patients have evidence of tunica albuginea mineralization at presentation on B-mode ultrasound. The nature of both small and large mineral deposits in PD plaques was characterized by Energy Dispersive X-ray Spectroscopy (EDS) and micro CT.

Methods

Tissue specimens were collected from PD patients after surgery with patients&[prime] consent and institutional approval and stored frozen. X-rays were used to identify post-surgical specimens with mineralization. The soft tissues in PD plaques with mineral foci were digested with 0.2% pronase for 2h followed by 0.025% bacterial collagenase P overnight at 37 ^oC. Mineral foci resistant to enzyme digestion were gold coated and analysed by EDS using a JEOL JSM electron microscope. Other PD plaques were fixed with ethanol and phosphotungstic acid (PTA) and imaged by micro CT.

Results

Mineral foci in PD plaques were resistant to enzyme digestions by the general protease pronase and subsequent digestion by bacterial collagenase. When the mineral content of the enzyme resistant foci were analysed by EDS they showed a Ca/P ratio of 1.80 +/- 0.09. The Ca/P ratios were very similar for both large and small foci. For comparison rabbit tibial bone treated in a similar manner had Ca/P ratio of 1.76 +/- 0.09. The location of the mineral within the collagenous plaques was imaged using micro CT with PTA as a contrast agent to stain the collagen fibers. Micro CT images of the mineralized plaques showed mineral deposition at the interface between collagenous layers with different degrees of PTA stain contrast.

Conclusions

Mineral foci in PD plaques were enzyme resistant. The high Ca/P ratio (1.80) of mineral deposits in PD plaques were indicative of mature hydroxyapatite (Ca/P 1.67) found in bone. This high ratio was similar in both small and large mineral foci in the PD enzyme resistant tissues. The location of the mineral deposits and adjacent unmineralized collagenous matrix could readily be visualized by micro CT when PTA was used to stain the collagen fibers.

Funding

None