Omer Kaymakcalan

ROCKII inhibition promotes the maturation of human pancreatic beta-like cells

Diabetes is linked to loss of pancreatic beta-cells. Pluripotent stem cells offer a valuable source of human beta-cells for basic studies of their biology and translational applications. However, the signalling pathways that regulate beta-cell development and functional maturation are not fully understood. Here we report a high content chemical screen, revealing that H1152, a ROCK inhibitor, promotes the robust generation of insulin-expressing cells from multiple hPSC lines. The insulin expressing cells obtained after H1152 treatment show increased expression of mature beta cell markers and improved glucose stimulated insulin secretion. Moreover, the H1152-treated beta-like cells show enhanced glucose stimulated insulin secretion and increased capacity to maintain glucose homeostasis after transplantation. Conditional gene knockdown reveals that inhibition of ROCKII promotes the generation and maturation of glucose-responding cells. This study provides a strategy to promote human beta-cell maturation and identifies an unexpected role for the ROCKII pathway in the development and maturation of beta-like cells.Our incomplete understanding of how pancreatic beta cells form limits the generation of beta-like cells from human pluripotent stem cells (hPSC). Here, the authors identify a ROCKII inhibitor H1152 as increasing insulin secreting cells from hPSCs and improving beta-cell maturation on transplantation in vivo.

Abstract 138: Treating Infected Wounds in the Era of Antibiotic Resistance

PURPOSE: We recently described a bioinspired material composed of nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) that induces efficient osteogenic differentiation of human mesenchymal stem cells (hMSCs) without the addition of exogenous growth factors, thereby suggestive of a promising, growth factorfree, materials-based method for clinically utilizable bone regeneration. We have previously reported that MC-GAG scaffolds autogenously induce BMP receptor signaling via the canonical (Smad1/5) pathway. However, the necessary and sufficient components of this mechanism remain unknown. Our current study evaluates the contribution of the non-canonical (MAP kinase) pathway in MC-GAG induced osteogenesis.

Abstract 129: Fabrication of the First Full-Scale Human Auricular Chondrocyte Derived Ear Scaffold for Clinical Application

PURPOSE: Trauma-induced heterotopic ossification (tHO) is the aberrant growth of ectopic bone in soft tissue, which develops in patients following severe musculoskeletal trauma. Much of HO literature focuses on a related pathology known as fibrodysplasia ossificans progressiva (FOP), which is caused by a hyperactivating mutation in the type I bone morphogenetic protein receptor (T1-BMPR) ACVR1 (ACVR1 R206H). Consequently, emphasis has been placed on developing inhibitors with improved specificity for ACVR1. However, patients who develop tHO do not harbor known ACVR1 mutations, and it is unclear whether emphasis on ACVR1-specific inhibition is beneficial for the treatment of tHO. Here investigate whether any single T1-BMPR is required for tHO, or whether these receptors perform overlapping roles during tHO development. We further evaluate the efficacy of the BMP ligand trap, Alk3Fc, as a broad-spectrum inhibitor of T1-BMP receptors in the treatment and prevention tHO.

Abstract 130: Better Living Through Chemistry

PURPOSE: The body responds to synthetic surfaces on implanted prosthetic devices with an inflammatory foreign body response (FBR), which results in the gradual deposition of a fibrous collagenous capsule. Capsular contracture (CC), the progressive growth and contraction of this peri-prosthetic capsule, is the most common complication of aesthetic and reconstructive breast surgery, affecting up to 47.5% of patients (1). CC causes breast pain, hardening, and deformity and is the most common indication for revision surgery. CC is thought to be due to an excessive FBR, however the etiology and pathophysiology of this process is poorly understood, and CC can occur in the absence of any putative risk factors. As such, there are no clinically approved therapies for prevention or treatment of CC. Rather, the complication is mitigated with re-operation and capsule excision, which often necessitates implant removal and replacement. Herein we altered the surface chemistry of silicone implants with Sigilon’s proprietary anti-inflammatory molecules, E9 and RZA15. These compounds are biocompatible small organic molecules which are covalently grafted to the surface of the implant. They are designed to reduce immune cell adhesion to the implant, leading to a truncated FBR and reduced fibrosis.

Abstract 15. Better Living through Chemistry: A Novel Breast Implant Surface Coating Significantly Reduces Peri-Prosthetic Capsule Formation

M oday, M arch 7, 2017 PURPOSE: Restoration of breast sensation following breast reconstruction is an evolving part of the reconstructive paradigm. Although spontaneous recovery of sensation has been reported following mastectomy, surgeons are advocating for innervated reconstructions using neurotization at the time of autologous reconstruction. In an effort to further elucidate the evidence basis for nerve coaptation, a meta-analysis of the literature was undertaken.

Toward Microsurgical Correction of Cleft Lip Ex Utero through Restoration of Craniofacial Developmental Programs

Background: Cleft lip with or without cleft palate is present in approximately one in 500 to 700 live births, representing the most common congenital craniofacial anomaly. Previously, the authors developed a unique murine model with compound Pbx deficiency that exhibits fully penetrant cleft lip with or without cleft palate. To investigate the possibility of tissue repair at an early gestational stage, the authors designed a minimally invasive surgical approach suitable for intrauterine repair using Wnt9b-soaked collagen microspheres to restore craniofacial developmental programs for cleft correction. Methods: Collagen microspheres with diameters ranging from 20 to 50 &mgr;m were fabricated to serve as a delivery vehicle for Wnt9b. At gestational day 11.5, wild-type and Pbx-deficient murine embryos were isolated. Microspheres soaked in murine purified Wnt9b protein were microsurgically implanted at the midface lambdoidal junction. Embryos were cultured in a 37°C modified whole-embryo culture system. Results: Targeted release of Wnt9b resulted in augmented Wnt expression at the lambdoidal junction. Microsurgical implantation of Wnt9b-soaked microspheres resulted in cleft correction in 27.1 percent of the Pbx-deficient embryos. The difference in the ratio of the areas of clefting between implanted and nonimplanted embryos was significant (p < 0.05). Conclusions: Ex utero correction of cleft lip with or without cleft palate in the authors’ murine model by means of microsurgical intervention and targeted delivery of Wnt proteins is an innovative and promising strategy. Although further refinement and optimization of this technique will be required to improve efficacy, the authors believe that this approach will open new avenues toward unconventional prenatal interventions for patients with cleft lip with or without cleft palate, and provide future approaches for prenatal repair of other congenital head and neck disorders.

Transient phase behavior of an elastomeric biomaterial applied to abdominal laparotomy closure

Secure closure of the fascial layers after entry into the peritoneal cavity is crucial to prevent incisional hernia, yet appropriate purchase of the tissue can be challenging due to the proximity of the underlying protuberant bowel which may become punctured by the surgical needle or strangulated by the suture itself. Devices currently employed to provide visceral protection during abdominal closure, such as the metal malleable retractor and Glassman Visceral Retainer, are unable to provide complete protection as they must be removed prior to complete closure. A puncture resistant, biocompatible, and degradable matrix that can be left in place without need for removal would facilitate rapid and safe abdominal closure. We describe a novel elastomer (CC-DHA) that undergoes a rapid but controlled solid-to-liquid phase transition through the application of a destabilized carbonate cross-linked network. The elastomer is comprised of a polycarbonate cross-linked network of dihydroxyacetone, glycerol ethoxylate, and tri(ethylene glycol). The ketone functionality of the dihydroxyacetone facilitates hydrolytic cleavage of the carbonate linkages resulting in a rapidly degrading barrier that can be left in situ to facilitate abdominal fascial closure. Using a murine laparotomy model we demonstrated rapid dissolution and metabolism of the elastomer without evidence of toxicity or intraabdominal scarring. Furthermore, needle puncture and mechanical properties demonstrated the material to be both compliant and sufficiently puncture resistant. These unique characteristics make the biomaterial extraordinarily useful as a physical barrier to prevent inadvertent bowel injury during fascial closure, with the potential for wider application across a variety of medical and surgical applications. STATEMENT OF SIGNIFICANCE Fascial closure after abdominal surgery requires delicate maneuvers to prevent incisional hernia while minimizing risk for inadvertent bowel injury. We describe a novel biocompatible and biodegradable polycarbonate elastomer (CC-DHA) comprised of dihydroxyacetone, glycerol ethoxylate, and tri(ethylene glycol), for use as a rapidly degrading protective visceral barrier to aid in abdominal closure. Rapid polymer dissolution and metabolism was demonstrated using a murine laparotomy model without evidence of toxicity or intraabdominal scarring. Furthermore, mechanical studies showed the material to be sufficiently puncture resistant and compliant. Overall, this new biomaterial is extraordinary useful as a physical barrier to prevent inadvertent bowel injury during fascial closure, with the potential for wider application across a variety of medical and surgical applications.