Prevention of cisplatin-induced nephrotoxicity by kidney-targeted siRNA delivery.

Cisplatin is a potent and widely used chemotherapy agent, however, nephrotoxicity limits its use. Many patients need to pause or withdraw from chemotherapy to prevent acute kidney injury.To prevent cisplatin damage, we designed chitosan/siRNA nanoparticleswhich are nontoxic and are readily taken up by HEK293 cells. The nanoparticlescontainedsiRNA against cationic membrane transport (OCT1&2) and apoptosis related proteins (p53, PKCδ, and γGT). In mice treated with cisplatin, serum creatinine levels increased from 15 to 88 mg/dL andblood urea nitrogenlevels increased from 0.25 to 1.7 mg/dL, however, siRNA nanoparticles significantly limited these levels to 30 mg/dL and 0.55 mg/dL, respectively.Western and IHC analyses showed lower p53, PKCδ, and γGT expressions in siRNA treated mice. Histomorphological evaluation revealed high-level protection of kidney proximal tubules from cisplatin damage. Protein expressions and extent of kidney protection were directly correlated with number of siRNA applications. Our results suggest that this novel approach for kidney-targeted delivery of select siRNAs may represent a promising therapy for preventing cisplatin-induced nephrotoxicity. Furthermore, this or other similarly sized nanocarriers could potentially be utilized to passively target kidneys for diagnostic, protective, or treatment purposes.

A nanoengineered topical transmucosal cisplatin delivery system induces anti-tumor response in animal models and patients with oral cancer.

Despite therapeutic advancements, oral cavity squamous cell carcinoma (OCSCC) remains a difficult disease to treat. Systemic platinum-based chemotherapy often leads to dose-limiting toxicity (DLT), affecting quality of life. PRV111 is a nanotechnology-based system for local delivery of cisplatin loaded chitosan particles, that penetrate tumor tissue and lymphatic channels while avoiding systemic circulation and toxicity. Here we evaluate PRV111 using animal models of oral cancer, followed by a clinical trial in patients with OCSCC. In vivo, PRV111 results in elevated cisplatin retention in tumors and negligible systemic levels, compared to the intravenous, intraperitoneal or intratumoral delivery. Furthermore, PRV111 produces robust anti-tumor responses in subcutaneous and orthotopic cancer models and results in complete regression of carcinogen-induced premalignant lesions. In a phase 1/2, open-label, single-arm trial (NCT03502148), primary endpoints of efficacy (≥30% tumor volume reduction) and safety (incidence of DLTs) of neoadjuvant PRV111 were reached, with 69% tumor reduction in ~7 days and over 87% response rate. Secondary endpoints (cisplatin biodistribution, loco-regional control, and technical success) were achieved. No DLTs or drug-related serious adverse events were reported. No locoregional recurrences were evident in 6 months. Integration of PRV111 with current standard of care may improve health outcomes and survival of patients with OCSCC.

Histopathological and biomechanical evaluation of tenocyte seeded allografts on rat Achilles tendon regeneration.

Tendon injuries in humans as well as in animals' veterinary medicine are problematic because tendon has poor regenerative capacity and complete regeneration of the ruptured tendon is never achieved. In the last decade there has been an increasing need of treatment methods with different approaches. The aim of the current study was to improve the regeneration process of rat Achilles tendon with tenocyte seeded decellularized tendon matrices. For this purpose, Achilles tendons were harvested, decellularized and seeded as a mixture of three consecutive passages of tenocytes at a density of 1 × 10(6) cells/ml. Specifically, cells with different passage numbers were compared with respect to growth characteristics, cellular senescence and collagen/tenocyte marker production before seeding process. The viability of reseeded tendon constructs was followed postoperatively up to 6 months in rat Achilles tendon by histopathological and biomechanical analysis. Our results suggests that tenocyte seeded decellularized tendon matrix can significantly improve the histological and biomechanical properties of tendon repair tissue without causing adverse immune reactions. To the best of our knowledge, this is the first long-term study in the literature which was accomplished to prove the use of decellularized matrix in a clinically relevant model of rat Achilles tendon and the method suggested herein might have important implications for translation into the clinic.

Development of a Nanoparticle-Embedded Chitosan Sponge for Topical and Local Administration of Chemotherapeutic Agents.

The following work describes the development of a novel noninvasive transmucosal drug delivery system, the chitosan sponge matrix (CSM). It is composed of cationic chitosan (CS) nanoparticles (NPs) that encapsulate cisplatin (CDDP) embedded within a polymeric mucoadhesive CS matrix. CSM is designed to swell up when exposed to moisture, facilitating release of the NPs via diffusion across the matrix. CSM is intended to be administered topically and locally to mucosal tissues, with its initial indication being oral cancer (OC). Currently, intravenous (IV) administered CDDP is the gold standard chemotherapeutic agent used in the treatment of OC. However, its clinical use has been limited by its renal and hemotoxicity profile. We aim to locally administer CDDP via encapsulation in CS NPs and deliver them directly to the oral cavity with CSM. It is hypothesized that such a delivery device will greatly reduce any systemic toxicity and increase antitumor efficacy. This paper describes the methods for developing CSM and maintaining the integrity of CDDP NPs embedded in the CSM.

Hydroxyapatite nanorod-reinforced biodegradable poly(L-lactic acid) composites for bone plate applications.

Novel PLLA composite fibers containing hydroxyapatite (HAp) nanorods with or without surface lactic acid grafting were produced by extrusion for use as reinforcements in PLLA-based bone plates. Fibers containing 0-50% (w/w) HAp nanorods, aligned parallel to fiber axis, were extruded. Lactic acid surface grafting of HAp nanorods (lacHAp) improved the tensile properties of composites fibers better than the non-grafted ones (nHAp). Best tensile modulus values of 2.59, 2.49, and 4.12 GPa were obtained for loadings (w/w) with 30% lacHAp, 10% nHAp, and 50% amorphous HAp nanoparticles, respectively. Bone plates reinforced with parallel rows of these composite fibers were molded by melt pressing. The best compressive properties for plates were obtained with nHAp reinforcement (1.31 GPa Young's Modulus, 110.3 MPa compressive strength). In vitro testing with osteoblasts showed good cellular attachment and spreading on composite fibers. In situ degradation tests revealed faster degradation rates with increasing HAp content. To our knowledge, this is the first study containing calcium phosphate-polymer nanocomposite fibers for reinforcement of a biodegradable bone plate or other such implants and this biomimetic design was concluded to have potential for production of polymer-based biodegradable bone plates even for load bearing applications.

The role of multiple toll-like receptor signalling cascades on interactions between biomedical polymers and dendritic cells.

Biomaterials are used in several health-related applications ranging from tissue regeneration to antigen-delivery systems. Yet, biomaterials often cause inflammatory reactions suggesting that they profoundly alter the homeostasis of host immune cells such as dendritic cells (DCs). Thus, there is a major need to understand how biomaterials affect the function of these cells. In this study, we have analysed the influence of chemically and physically diverse biomaterials on DCs using several murine knockouts. DCs can sense biomedical polymers through a mechanism, which involves multiple TLR/MyD88-dependent signalling pathways, in particular TLR2, TLR4 and TLR6. TLR-biomaterial interactions induce the expression of activation markers and pro-inflammatory cytokines and are sufficient to confer on DCs the ability to activate antigen-specific T cells. This happens through a direct biomaterial-DC interaction although, for degradable biomaterials, soluble polymer molecules can also alter DC function. Finally, the engagement of TLRs by biomaterials profoundly alters DC adhesive properties. Our findings could be useful for designing structure-function studies aimed at developing more bioinert materials. Moreover, they could also be exploited to generate biomaterials for studying the molecular mechanisms of TLR signalling and DC activation aiming at fine-tuning desired and pre-determined immune responses.