Tannic Acid (TA) is a naturally occurring antioxidant polyphenol that has gained popularity over the past decade in the field of biomedical research for its unique biochemical properties. Tannic acid, typically extracted from oak tree galls, has been used in many important historical applications. TA is a key component in vegetable tanning of leather, iron gall ink, red wines, and as a traditional medicine to treat a variety of maladies. The basis of TA utility is derived from its many hydroxyl groups and its affinity for forming hydrogen bonds with proteins and other biomolecules. Today, the study of TA has led to the development of many new pharmaceutical and biomedical applications. TA has been shown to reduce inflammation as an antioxidant, act as an antibiotic in common pathogenic bacterium, and induce apoptosis in several cancer types. TA has also displayed antiviral and antifungal activity. At certain concentrations, TA can be used to treat gastrointestinal disorders such as hemorrhoids and diarrhea, severe burns, and protect against neurodegenerative diseases. TA has also been utilized in biomaterials research as a natural crosslinking agent to improve mechanical properties of natural and synthetic hydrogels and polymers, while also imparting anti-inflammatory, antibacterial, and anticancer activity to the materials. TA has also been used to develop thin film coatings and nanoparticles for drug delivery. In all, TA is fascinating molecule with a wide variety of potential uses in pharmaceuticals, biomaterials applications, and drug delivery strategies.

Breast cancer is the most common invasive cancer in women worldwide. Surgical removal of the breast tumor and subsequent reconstructive surgery can result in complications such as infection or necrosis of transplanted adipose tissue. Breast cancer recurrence is also a serious concern for patients. Our group has developed a tannic acid/collagen bead material that has the potential to be used as an injectable adipose tissue regenerative device to replace lipofilling. Tannic acid is a polyphenol with anticancer and antibiotic properties. The objective of this study was to establish the biocompatibility of an injectable tannic acid/collagen bead implant material in an in vivo rat model. The injection of the tannic acid-collagen type I bead device was minimally invasive. No symptoms of infection, tissue necrosis, or widespread chronic inflammation were observed. After 12 weeks, implants showed incorporation into native tissue with no fibrous encapsulation. Despite the presence of inflammatory cells in the remaining beads, fat tissue growth and collagen redistribution were observed within the beads over 12 weeks, showing incorporation within native subcutaneous tissue and indicating good biocompatibility and bioactivity of the implant. Our results demonstrate that the tannic acid/collagen bead scaffold has good biocompatibility and works as an adipocyte tissue regeneration and reconstructive device.

Breast cancer is the most commonly diagnosed cancer among women worldwide. Surgical removal of tumors is often necessary and many patients suffer complications due to subsequent breast reconstruction. A safe and effective breast reconstructive material is needed for patients recovering from surgical removal of small breast cancer tumors. Our lab has developed injectable collagen/tannic acid beads seeded with patient-derived preadipocytes for regeneration of healthy breast tissue in patients post-lumpectomy. Previous research indicates that the inclusion of tannic acid in the matrix imparts an anticancer property. This research seeks to determine the variables needed to control collagen/tannic acid bead diameter and seeded cell attachment, which are essential to proper bead implantation and function. We found that as tannic acid concentration increases within the beads, cell attachment decreases. Bead diameter is controlled by bead generator voltage, solution osmolality, the degree of cell attachment, and tannic acid concentrations. Higher voltages resulted in significant decrease in bead diameter. Collagen/tannic acid beads decreased in diameter when placed in solutions of increasing osmolality. Higher degrees of cell attachment across the surface of the beads were associated with a significant decrease in diameter. In beads made with high concentrations of tannic acid, bead diameter was found to decrease. Collagen/TA beads are a promising subdermal tissue regenerative matrix with anticancer activity as an alternative to simple lipofilling in breast reconstructive procedures. This study was conducted to better understand the properties of collagen/TA beads in order to improve injection efficacy and tissue regenerative activity.

Highlights Nutrition associated glycoxidation promotes aggressive prostate tumor growth. AGEs, the final product of glycoxidation were a key pro-tumorigenic effector. Dietary-AGE mediated effects were dependent upon stromal RAGE expression. AGE-RAGE signaling caused a regulatory program of activated stroma & CAF activation. Dietary-AGE effects were reproduced using in vivo, ex vivo and in vitro models.

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