This will be a single center, prospective, split-arm clinical study in which subjects will be randomized to which arm will be treated with Sciton's broad band light (BBL) treatment. All subjects will have their arms shaved prior to the procedure and cleaned thoroughly with alcohol. After the procedure a zinc-based sunscreen will be applied to both arms.
Before each of the four treatments, and 1 month after the last treatment, the subjects' number and square area of ecchymoses will be measured by an evaluator and photographs will be taken. Side effects will be measured the same day as the treatment as well as 1 day, 2 days, and 7 days after the first treatment.
A final assessment will be done by taking two skin biopsies from the subjects with senile purpura, one on treated skin and one on untreated skin, and one skin biopsy on untreated skin in the younger controls. The skin specimens will be bisected and one half will be submerged immediately in 10x volumes of formalin while the other half of the biopsy will be submerged immediately in 10x volumes of RNAlater (Thermo Fisher Scientific, Waltham, MA). These specimens will then be coded and sent to blinded evaluators that will embed half in paraffin sections and then stain them with hematoxylin and eosin (H\&E), von Giesen and or periodic acid-Schiff (PAS).
Epidermal thickness will be measured on H\&E-stained sections using the AxioVision image analysis software (Carl Zeiss Microimaging, Thornwood, NY). The epithelial thickness may vary from area to area within the biopsy. The thickness of the epithelium in µm will be measured at 6 points in each biopsy and averaged. Von Giesen-stained sections will be examined for elastosis, and PAS-stained sections will be examined for collagen.
Total RNA will be extracted using TRIzol Reagent (Thermo Fisher Scientific, Waltham, MA) and the RNeasy mini kit (Qiagen, Valencia, CA). RNA will be reverse transcribed using qScript™ cDNA Synthesis Kit (QuantaBio, Beverly, MA). Real-time qPCR reactions will be carried out using PerfeCTa SYBR® Green SuperMix (QuantaBio, Beverly, MA) in triplicates. Gene expression levels will be normalized to a housekeeping gene, and analyzed using t test of means and SEM. Potential analysis include various biomarkers for dermal remodeling (e.g., collagen type I, elastin), epidermal differentiation (e.g., keratin 1, filaggrin), and vascular changes (e.g., endothelin, Ang).
