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Complete removal of cancerous tissue and preservation of breast cosmesis with a single breast conserving surgery (BCS) is essential for surgeons. New and better options would allow them to more consistently achieve this goal and expand the number of women that receive this preferred therapy, while minimizing the need for re-excision and revision procedures or more aggressive surgical approaches (i.e., mastectomy). We have developed and evaluated a regenerative tissue filler that is applied as a liquid to defects during BCS prior to transitioning to a fibrillar collagen scaffold with soft tissue consistency. Using a porcine simulated BCS model, the collagen filler was shown to induce a regenerative healing response, characterized by rapid cellularization, vascularization, and progressive breast tissue neogenesis, including adipose tissue and mammary glands and ducts. Unlike conventional biomaterials, no foreign body response or inflammatory-mediated “active” biodegradation was observed. The collagen filler also did not compromise simulated surgical re-excision, radiography, or ultrasonography procedures, features that are important for clinical translation. When post-BCS radiation was applied, the collagen filler and its associated tissue response were largely similar to non-irradiated conditions; however, as expected, healing was modestly slower. This in situ scaffold-forming collagen is easy to apply, conforms to patient-specific defects, and regenerates complex soft tissues in the absence of inflammation. It has significant translational potential as the first regenerative tissue filler for BCS as well as other soft tissue restoration and reconstruction needs.

Summary Blastomycosis is a serious and potentially fatal infection by the thermally dimorphic fungus Blastomyces dermatitidis. PCR assays targeting the BAD-1 virulence gene promoter have been developed to aid in the detection of the pathogen in clinical and environmental samples. However, little is known regarding the genetic diversity of B. dermatitidis and how this might affect the performance characteristics of these assays. We explored the genetic relatedness of 106 clinical and environmental isolates of B. dermatitidis using a previously described rDNA PCR RFLP assay. In addition, we looked for polymorphisms in the promoter region upstream of BAD-1. RFLP analysis showed that all isolates fell into one of five genotypic groups, designated A through E. Genotypic groups A and B predominated, comprising 50/106 (47.2%) and 51/106 (48.1%) of isolates, respectively. Three of 106 (2.8%) isolates were genotype C. Genotypes D and E represented novel genotypes and were each associated with single clinical isolates. PCR of the BAD-1 promoter revealed significant size differences among amplification products. Fifty one of 106 isolates (50/50 RFLP genotypic group A and 1/51 genotypic group B) had amplicons of 663 bp – nearly twice the size of the expected product. Sequence analysis of amplification products from 17 representative isolates revealed four haplotypes and showed that the size disparity was due to two large insertions. Because these insertions were present in a high percentage of isolates, the utility of the PCR assays for diagnostic purposes could be affected. It is possible that the larger PCR product may have amplified less efficiently and that the larger amplicon could have been misinterpreted as a non-specific product. However, the novel RFLP genotypes and multiple BAD-1 haplotypes may prove useful as markers in population genetic studies.

Tissue engineered vascular grafts (TEVGs) using scaffolds fabricated from braided poly(glycolic acid) (PGA) fibers coated with poly(glycerol sebacate) (PGS) are developed. The approach relies on in vivo tissue engineering by which neotissue forms solely within the body after a scaffold has been implanted. Herein, the impact of altering scaffold braid design and scaffold coating on neotissue formation is investigated. Several combinations of braiding parameters are manufactured and evaluated in a Beige mouse model in the infrarenal abdominal aorta. Animals are followed with 4D ultrasound analysis, and 12 week explanted vessels are evaluated for biaxial mechanical properties as well as histological composition. Results show that scaffold parameters (i.e., braiding angle, braiding density, and presence of a PGS coating) have interdependent effects on the resulting graft performance, namely, alteration of these parameters influences levels of inflammation, extracellular matrix production, graft dilation, neovessel distensibility, and overall survival. Coupling carefully designed in vivo experimentation with regression analysis, critical relationships between the scaffold design and the resulting neotissue that enable induction of favorable cellular and extracellular composition in a controlled manner are uncovered. Such an approach provides a potential for fabricating scaffolds with a broad range of features and the potential to manufacture optimized TEVGs.

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