Patch esophagoplasty with a free proximal lateral leg flap for focal stricture of the cervical esophagus: A case report

DNA Methylation Dynamics During Esophageal Epithelial Regeneration Following Repair with Acellular Silk Fibroin Grafts in Rat

Esophageal pathologies such as atresia and benign strictures often require surgical reconstruction with autologous tissues to restore organ continuity. Complications such as donor site morbidity and limited tissue availability have spurred the development of acellular grafts for esophageal tissue replacement. Acellular biomaterials for esophageal repair rely on the activation of intrinsic regenerative mechanisms to mediate de novo tissue formation at implantation sites. Previous research has identified signaling cascades involved in neoepithelial formation in a rat model of onlay esophagoplasty with acellular silk fibroin grafts, including phosphoinositide 3-kinase (PI3K), and protein kinase B (Akt) signaling. However, it is currently unknown how these mechanisms are governed by DNA methylation (DNAme) during esophageal wound healing processes. Reduced-representation bisulfite sequencing is performed to characterize temporal DNAme dynamics in host and regenerated tissues up to 1 week postimplantation. Overall, global hypermethylation is observed at postreconstruction timepoints and an inverse correlation between promoter DNAme and the expression levels of differentially expressed proteins during regeneration. Site-specific hypomethylation targets genes associated with immune activation, while hypermethylation occurs within gene bodies encoding PI3K-Akt signaling components during the tissue remodeling period. The data provide insight into the epigenetic mechanisms during esophageal regeneration following surgical repair with acellular grafts.

Molecular mechanisms of esophageal epithelial regeneration following repair of surgical defects with acellular silk fibroin grafts

Constructive remodeling of focal esophageal defects with biodegradable acellular grafts relies on the ability of host progenitor cell populations to repopulate implant regions and facilitate growth of de novo functional tissue. Intrinsic molecular mechanisms governing esophageal repair processes following biomaterial-based, surgical reconstruction is largely unknown. In the present study, we utilized mass spectrometry-based quantitative proteomics and in silico pathway evaluations to identify signaling cascades which were significantly activated during neoepithelial formation in a Sprague Dawley rat model of onlay esophagoplasty with acellular silk fibroin scaffolds. Pharmacologic inhibitor and rescue experiments revealed that epithelialization of neotissues is significantly dependent in part on pro-survival stimuli capable of suppressing caspase activity in epithelial progenitors via activation of hepatocyte growth factor receptor (c-MET), tropomyosin receptor kinase A (TrkA), phosphoinositide 3-kinase (PI3K), and protein kinase B (Akt) signaling mechanisms. These data highlight the molecular machinery involved in esophageal epithelial regeneration following surgical repair with acellular implants.

Reconstruction of cervical and upper thoracic esophagus with a free posterior tibial artery perforator flap: A case report

INTRODUCTION

Esophageal window defect in patients with esophageal resection could be challenging to repair. In this case report, a free posterior tibial artery perforator flap (FPTAPF) was used for semi-circumference patch esophagoplasty.

PATIENT CONCERNS

For this 47-year-old male patient with recurrent laryngeal nerve schwannoma invading cervical and upper thoracic esophagus, cervical and upper thoracic esophageal reconstruction following tumor resection was needed DIAGNOSIS:: Pathologic result demonstrated recurrent laryngeal nerve schwannoma. Ultrasound examination detected a tumor (7 cm × 6 cm × 3 cm) located behind the right thyroid lobe, and contrast-enhanced computed tomography scan revealed that tumor was located between the cervical esophagus and trachea, and compressed these structures.

INTERVENTIONS

The tumor had a size of 7 cm × 6 cm × 3 cm, and the semi-circumference defect of the cervical and upper thoracic esophagus was about 7 cm in length after complete tumor resection. A 7 cm × 4 cm FPTAPF was designed and harvested for esophageal reconstruction.

OUTCOMES

The posterior tibial flap survived well and satisfactory recovery of esophageal function was obtained with no significant complications. No local tumor relapse was indicated by computed tomography during the 2-year postoperative follow-up.

CONCLUSION

This case highlights the stable performance of FPTAPF when used for the reconstruction of large esophageal window defect.

Bi-layer silk fibroin grafts support functional tissue regeneration in a porcine model of onlay esophagoplasty

Partial circumferential, full thickness defects of the esophagus can occur as a result of organ perforation or tumour resection, or during surgical reconstruction of strictured segments. Complications associated with autologous tissue flaps conventionally utilized for defect repair necessitate the development of new graft options. In this study, bi-layer silk fibroin (BLSF) scaffolds were investigated for their potential to support functional restoration of partial circumferential defects in a porcine model of esophageal repair. Onlay thoracic esophagoplasty with BLSF matrices (~3 x 1.5 cm) was performed in adult swine (N = 6) for 3 months of implantation. All animals receiving BLSF grafts survived with no complications and were capable of solid food consumption. Radiographic esophagrams revealed preservation of organ continuity with no evidence of contrast extravasation or strictures. Fluoroscopic analysis demonstrated peristaltic contractions. Ex vivo tissue bath studies displayed contractile responses to carbachol, electric field stimulation, and KCl while isoproterenol produced tissue relaxation. Histological and immunohistochemical evaluations of neotissues showed a stratified, squamous epithelium, a muscularis mucosa composed of smooth muscle bundles, and a muscularis externa organized into circular and longitudinal layers, with a mix of striated skeletal muscle fascicles interspersed with smooth muscle. De novo innervation and vascularization were observed throughout the graft sites and consisted of synaptophysin-positive neuronal boutons and vessels lined with CD31-positive endothelial cells. The results of this study demonstrate that BLSF scaffolds can facilitate constructive remodeling of partial circumferential, full thickness esophageal defects in a large animal model. Copyright © 2017 John Wiley & Sons, Ltd.

Reconstruction of late esophagus perforation after anterior cervical spine fusion with an adipofascial anterolateral thigh free flap: A case report

Reconstruction of late esophageal perforation usually requires flap surgery to achieve wound healing. However, restoring the continuity between the digestive tract and retropharyngeal space to allow for normal swallowing remains a technical challenge. In this report, we describe the use of a thin and pliable free adipofascial anterolateral thigh (ALT) flap in a 47-year-old tetraplegic man with a history of C5-C6 fracture presented with a large posterior esophagus wall perforation allowing an easier flap insetting for a successful wound closure. The postoperative course was uneventful and mucosalization of the flap was confirmed by esophagoscopy 4 weeks postsurgery. The patient tolerated normal diet and maintained normal swallowing during a follow-up of 3 years postoperatively. The adipofascial ALT flap may provide easier insetting due to the thin and pliable layer of adipofascial tissue for reconstructing large defects of the posterior wall of the esophagus by filling the retroesophageal space.