PLGA encapsulated polyphenols to ameliorate IBD. - Abstract
Green tea has received increased attention recently, due to several epidemiological and clinical studies
showing a positive relationship between consumption and disease prevention. Benefits include reduced risk of
cardiovascular diseases (e.g. myocardial infarction, hypertension, atherosclerosis), neurodegenerative
diseases (e.g. Parkinson’s and Alzheimer’s disease), and certain cancers (e.g. gastric, breast and cervical
cancer). Supplements can even help maintain healthy body weight and lipid profiles. Clinical activity has been
demonstrated in leukemia and by our group in inflammatory bowel disease (IBD). These effects are attributed
to the polyphenolic flavonoid compounds known as catechins (i.e., polyphenols) present in high amounts. Yet,
poor stability, low oral bioavailability and inconsistent intestinal absorption remain problematic. If these
shortcomings were overcome, the impact of green tea supplementation could be dramatically improved and
novel, efficacious pharmaceutical products aimed at maintaining health developed. The hypothesis behind this
application is that encapsulation into poly D,L-lactide-co-glycolide (PLGA) microspheres will improve the
delivery and thus efficacy of green tea’s polyphenols via the oral route. Importantly, PLGA is already approved
by the FDA and EMA for human use. Thus, PLGA-based micro-particles are in a good position for use in
products intended for human consumption. Considering these observations, the proposed studies will test an
oral PLGA encapsulated polyphenol formulation for prophylactic use. In Aim 1, we will determine whether oral
administration of polyphenol loaded microspheres is superior to parenteral soluble material in limiting murine
IBD using a prophylactic iteration of the acute DSS-induced colitis model. We will then optimize the
prophylactic protocol and examine the effects of treatment on the phenotypic and functional properties of
colonic LP and MLN mononuclear cells. In Aim 2, we will determine whether oral administration of polyphenol
microspheres is similarly effective in the CD4+CD25- T-cell reconstituted SCID mouse model of colitis This
model is also in routine operation in our laboratory. We will elucidate immunological mechanisms, as well as
monitor long-term efficacy and systemic side effects. Future work will include pharmacokinetic, dose-ranging
toxicology studies, as well as product development (drug product and drug substance) efforts aimed at novel
pharmaceutical products. If the proposed studies are successful the hope is that the benefits of green tea, long
recognized by the ancients, may at last be translated and optimized into prophylactic benefit for IBD patients.