Novel Treatment of Anal Fistulas and Endovascular Drug Delivery for Peripheral Arterial Disease

Abstract

ABSTRACT #1: Peripheral Arterial Disease Drug Delivery

Peripheral arterial disease affects 6.5 million people over the age of 40 in the USA. This blood circulation disorder blocks peripheral arterial blood vessels, restricting oxygen-rich blood flow to the limbs and increasing chances of limb loss. Unfortunately, although treatments exist to open the blood vessel, 12% of patients still experience recurrence. The cause of this is intimal hyperplasia. The drug Amlexanox has been shown to reduce intimal hyperplasia in dogs. In this study we propose a stretch-release drug delivery platform for delivering Amlexanox. This platform consists of a cyclodextrin acrylamide gel coating loaded with drug and inserted onto angioplasty balloons. Drug measurements show that this coating releases statistically significant amounts of drug into mock vessels upon balloon expansion. The coating can also stretch up to 21 times its original length. Successful bonding of the gel to commercial latex and silicone balloon catheters was achieved with the addition of oxygen scavengers and benzophenone, paired with UV light at a close distance. Future work entails coating integrity testing, drug dosing analysis, and in-vivo rat studies. In conclusion, this platform coating technology has been shown to release drugs during balloon expansion and has promise for enabling delivery of novel drug treatments.

ABSTRACT #2: Novel Treatment of Anal Fistulas

There are considerable unmet needs for treating anorectal fistulas. The current gold standard of care, an advancement flap, only has a 45-76% success rate, and 7% incontinence rate. Other effective treatments exist such as the LIFT procedure or fistulotomy, but many of these procedures still put the sphincter muscles at risk, most work only for specific situations, and none are without complications. In this study, a novel approach of closing the internal fistula opening is discussed. By closing the opening with a tissue-compatible adhesive patch, less bacteria enters the fistula from the anal or rectal cavity, and the internal opening is fully sealed off to facilitate healing. Preliminary results for rectal, anal, and vaginal tissue show that this patch can withstand more than 3-5 times the maximum estimated shear stress that patch would be subjected to for hard feces (1673 Pa). This technology is of interest to Chron’s patients, for whom interventional surgery is increasingly risky. This technology has significant clinical translational opportunity since it is low risk, non-invasive, and reversible on-demand. Literature already supports the in-vivo biocompatibility of this patch. Future work includes in-vivo studies to confirm clinical efficacy. In sum, this new proposed technology shows promise as an alternative to outperform advancement flaps for anorectal fistula treatment.