Tissue-engineered provisional matrix as a novel approach to enhance diabetic wound healing.

Inherent pathologies associated with diabetic wound microenvironment including increased proteolysis, inflammatory dysregulation, and impaired neovascularization prevent timely resolution of chronic diabetic ulcers. It is hypothesized that augmentation of local wound microenvironment with a stable provisional matrix formed by proteolysis-resistant angiogenic peptide nanofibers (NFs) will create permissive environment for attenuated inflammation, enhanced neovascularization, and improved diabetic wound healing. Using murine excisional wound healing models, full-thickness dorsal skin wounds were treated with either NFs or control solutions (phosphate buffered saline; hyaluronic acid) and analyzed for morphology, inflammatory response, neovascularization, and biomechanical properties. NF treatment of diabetic wounds stimulated formation of a robust pro-angiogenic in situ tissue-engineered provisional matrix leading to a significant decrease in wound inflammatory cell infiltration and proinflammatory interleukin-6 levels, a significant increase in endothelial and endothelial progenitor cell infiltration, vascular endothelial growth factor levels, and neovascularization (day 7), as well as improved wound morphology, accelerated wound closure, and significantly stronger repair tissue (day 28). These results suggest that appropriate design of provisional matrix may compensate for some of the complex disruptions in diabetic wound microenvironment and provide missing cues to cells and direct in situ responses toward improved healing, which is promising for future development of new therapies for diabetic ulcers.

Phase I study of H5.020CMV.PDGF-beta to treat venous leg ulcer disease.

Venous leg ulcers are a prevalent nonhealing wound of the lower extremity. Although topically applied growth factors successfully improve wound repair in animal studies, similar studies on humans with venous leg ulcers have not been successful. This study was designed to evaluate the acute safety and biologic feasibility of peri-ulcer injection of a replication-incompetent adenoviral construct expressing platelet-derived growth factor-beta (PDGF-beta). In this phase I study, we demonstrate the initial safety, feasibility, and biologic plausibility of using H5.020CMV.PDGF-beta to treat venous leg ulcer disease.

Congenital high airway obstruction syndrome due to complete tracheal agenesis: an accident of nature with clues for tracheal development and lessons in management.

Congenital high airway obstruction syndrome (CHAOS) is a life-threatening condition characterized by complete blockage of the fetal airways associated with hydrops. We present a case of CHAOS due to the rare cause of complete tracheal agenesis. The ex utero intrapartum therapy (EXIT) strategy was employed to allow for neck and mediastinal exploration. Thymectomy allowed dissection to the level of the carina demonstrating the confluence of dilated mainstem bronchi but no trachea and no connection to the esophagus. A 2.5 endotracheal tube was inserted into the right mainstem bronchus and secured to the left clavicle. At 3 months of age, the infant succumbed to sepsis from Enterobacter mediastinitis due to friction between the tracheostomy tube and the nasogastric tube resulting in erosion of the esophagus. Complete tracheal agenesis, as seen in this case, is consistent with the failure of normal tracheal elongation as suggested by newer theories of foregut development. This case illustrates the most severe form of tracheal atresia causing CHAOS ever salvaged by the EXIT procedure at birth. The subsequent postnatal course highlights the need for early tracheal replacement in this particularly challenging form of CHAOS.

Permissive environment in postnatal wounds induced by adenoviral-mediated overexpression of the anti-inflammatory cytokine interleukin-10 prevents scar formation.

Wound healing in the mid-gestation fetus is scarless with minimal inflammation and a unique extracellular matrix. We have previously documented the relative lack of inflammatory cytokines in this environment. We demonstrate that interleukin (IL)-10 is highly expressed in mid-gestation human fetal skin but is absent in postnatal human skin. We hypothesize that overexpression of IL-10 in postnatal skin may replicate a permissive environment for scarless healing. To study the mechanism underlying this process we performed immunohistochemistry for IL-10 in human mid-gestation fetal and postnatal skin. We also determined if adenoviral-mediated overexpression of IL-10 could allow for scarless wound healing in a murine incisional wound model. Wounds were analyzed at 1-90 days postwounding for effects on scar formation, inflammatory response, and biomechanical properties. Ad-IL-10 reconstitutes a permissive environment for scarless healing as shown by reconstitution of a normal dermal reticular collagen pattern and distribution of dermal elements. Compared with controls, Ad-IL-10 treated wounds showed reduced inflammatory response and no difference in biomechanical parameters. Therefore, overexpression of IL-10 in postnatal wounds results in a permissive environment for scarless wound repair, possibly by replicating a fetal wound environment.

Tissue inhibitor of metalloproteinase-3 via oncolytic herpesvirus inhibits tumor growth and vascular progenitors.

Malignant solid tumors remain a significant clinical challenge, necessitating innovative therapeutic approaches. Oncolytic viral therapy is a nonmutagenic, biological anticancer therapeutic shown to be effective against human cancer in early studies. Because matrix metalloproteinases (MMP) play important roles in the pathogenesis and progression of cancer, we sought to determine if "arming" an oncolytic herpes simplex virus (oHSV) with an MMP-antagonizing transgene would increase virus-mediated antitumor efficacy. We generated oHSVs that express human tissue inhibitor of metalloproteinases 3 (TIMP3) or firefly luciferase and designated them rQT3 and rQLuc, respectively. We evaluated the antitumor efficacy of these viruses against neuroblastoma and malignant peripheral nerve sheath tumor (MPNST) xenografts. Relative to rQLuc, rQT3-infected primary human MPNST and neuroblastoma cells exhibited equivalent virus replication but increased cytotoxicity and reduced MMP activity. In vivo, rQT3-treated tumors showed delayed tumor growth, increased peak levels of infectious virus, immature collagen extracellular matrix, and reduced tumor vascular density. Remarkably, rQT3 treatment reduced circulating endothelial progenitors, suggesting virus-mediated antivasculogenesis. We conclude that rQT3 enhanced antitumor efficacy through multiple mechanisms, including direct cytotoxicity, elevated virus titer, and reduced tumor neovascularization. These findings support the further development of combined TIMP-3 and oncolytic virotherapy for cancer.

Oncolytic HSV and erlotinib inhibit tumor growth and angiogenesis in a novel malignant peripheral nerve sheath tumor xenograft model.

Malignant peripheral nerve sheath tumors (MPNSTs), driven in part by hyperactive Ras and epidermal growth factor receptor (EGFR) signaling, are often incurable. Testing of therapeutics for MPNST has been hampered by lack of adequate xenograft models. We previously documented that human MPNST cells are permissive for lytic infection by oncolytic herpes simplex viruses (oHSV). Herein we developed and characterized a xenograft model of human MPNST and evaluated the antitumor effects of oHSV mutants (G207 and hrR3) and the EGFR inhibitor, erlotinib. Additive cytotoxicity of these agents was found in human MPNST cell lines, suggesting that EGFR signaling is not critical for virus replication. Mice bearing human MPNST tumors treated with G207 or hrR3 by intraperitoneal or intratumoral injection showed tumor-selective virus biodistribution, virus replication, and reduced tumor burden. oHSV injection demonstrated more dramatic antitumor activity than erlotinib. Combination therapies showed a trend toward an increased antiproliferative effect. Both oHSV and erlotinib were antiangiogenic as measured by proangiogenic gene expression, effect on endothelial cells and xenograft vessel density. Overall, oHSVs showed highly potent antitumor effects against MPNST xenografts, an effect not diminished by EGFR inhibition. Our data suggest that inclusion of MPNSTs in clinical trials of oHSV is warranted.