Pluronic Hydrogel in Post Lumpectomy Breast Reconstruction Pluronic hydrogels being used in post lumpectomy breast reconstruction– One specific application of these hydrogels is the ability of them to be used in this *important to note the distinction between lumpectomy and mastectomy http://www.pharmainfo.net/devisarvani/hydrogels-novel-drug-delivery-system Solomon Swartz & Sana Majid

Outline Scope of the Problem Science of Hydrogels Treatment for Breast Cancer Reconstruction Science of Hydrogels Clinical Applications Looking Forward

Breast Cancer 12.5% of women will be affected within their lifetime Breast cancer death rates are the 2nd highest cancer death rates in women 2.7 million alive in the US with a history of breast cancer Offer some background on the scope of breast cancer Death rates are second only to lung cancer http://www.imaginis.com/files/media/transfer/img/breasthealth/CBE.gif

Treatment for Breast Cancer Chemotherapy Radiation Lumpectomy Full or partial mastectomy http://consciouslifenews.com/wp-content/uploads/2013/01/Cancer-Chemotherapy.jpg Many different methods of treating breast cancer, including but not limited to the methods listed above. One very common procedure is a lumpectomy. Lumpectomy involves the removal of lump or tumor from the affected breast tissue and is often considered to result in minimal deformation of the breast. This generally leads to breast asymmetry, which can be of significant concern to the patients. There are known psychological benefits to surgeries reestablishing the symmetry in the breasts. Breast reconstruction can be very important for the mental well being of these individuals http://rockisrocknbeads.blogspot.com/2012/10/mastectomy-photos-without-reconstruction.html

Current Reconstruction Techniques Autologous Procedures Pros: Little rejection, reformation of the breast, minimal complications Cons: Expensive, long procedures, surgery required No prosthetic implants currently available for lumpectomy patients The key is that these are lumpectomy procedures, and all prosthetics implants that are currently available only work for mastectomy patients. Autologous procedures are pretty much the only option for lumpectomy patients. These procedures are generally expensive http://www.breastcancer.org/Images/latissimus_dorsi_flap2%5B2%5D_tcm8-79052.jpg

Brief Introduction to Hydrogels First developed in the 1950s by Wichterle and Lim Valued for: Low Toxicities Abilities to absorb excess water Relative cost-effectiveness Ease of manufacture Polaxomers (Pluronics) were later synthesized in 1973 http://upload.wikimedia.org/wikipedia/commons/4/48/Prof._Ing._RTDr._Otto_Wichterle.jpg

Pluronics Thermosensitive Cold=liquid Warm=solid Rise in temperatures cause degradation of H-bonding of ester bonds in PPO, causing micelle formation Reversible process Sol-gel transition temperatures vary based on polymer segment lengths and concentration Unique tri-block copolymer structure provides Explain a little bit of the chemistry behind it here The two outer polymer chains consist of hydrophilic Poly-ethylene oxide while the inner chain consists of poly-propylene oxide Unique property of propylene oxide– hydrophilic at low temperatures but hydrophobic at higher temperatures viscosity change rate may also vary based on additions of other hydrogel components http://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Micelle_scheme-en.svg/250px-Micelle_scheme-en.svg.png

How it Works Hydrogels will degrade over time– need to prolong this Can’t use traditional cross-linking methods Divalent calcium ion, used for sustained drug delivery, can’t be used due to its disruption of X-ray Following a partial mastectomy, patients may require follow-up X-ray of the damaged area. Modification of the pluronic to enable cross-linkage via radiation treatment The crosslinking reaction is irreversible After modifications, the gel is no longer completely thermoreversible, which slows down the degradation process, but doesn’t halt it Serve as cell carriers for tissue regeneration– because the pluronics will degrade over time, we want it to serve as a scaffold for tissue regrowth and have growth factors (HGH?) to allow that to happen Different hydrogel brands carry different types of cells—human adipose tissue-derived precursor cells? Can also contain adult stem cells

Clinical Applications Applied non- invasively via hypodermic needle and syringe Solution is injected cold as a liquid and natural body temperatures cause the solution to self-assemble in-vivo. http://www.scifighting.com/wp-content/uploads/2013/02/Syringe-with-hypodermic-n-001.jpg Thermosensitivity of pluronics enables this material to be applied non-invasively via hypodermic needle and syringe. Following either lumpectomy or partial mastectomy, the solution is injected cold as a liquid and natural body temperatures cause the solution to self-assemble in-vivo. Must be performed prior to radiation treatment to enable effective cross-linking of the micelle matrix

Clinical Applications Pros Cons No surgery Less infection Mechanical properties of gel mimic native breast tissue Cost Effective No maintenance required Not applicable for mastectomy or large partial mastectomy patients Currently not tested clinically for viability Autologous procedures are generally much more expensive, as they require a length surgery which is often quite complicated and can have problems. Autologous procedures also have donor site morbidity and secondary site infection Cost: Still in clinical trials so we don’t know if ti will yet be covered by insurance, but it is very affordable to it will likely be an option

Looking Forward Improvements Complications Breast Symmetry Increased self-confidence Potential for Tissue Regeneration Psychological Benefits Inflammation Failure to cross-link Required readministration

References Elluru, M., et al. “Synthesis and characterization of biocompatible hydrogel using Pluronics-based block copolymers.” Polymer. 54 (2013): 2088-2095. Web. www.breastcancer.org