Long-term results of the application of solvent-dehydrated bone xenograft and duramater xenograft for the healing of oroantral osseous defects: a pilot experimental study

Abstract –  The aim of this study was to investigate the long-term effects of the use of human cadaveric solvent-dehydrated bone graft and duramater as a barrier membrane for the treatment of oroantral communication. Standard oroantral osseous defects were created in five minipigs. Subjects received cancellous bone graft in the form of block or microchips, duramater or a combination of bone and membrane. Uneventful healing was achieved in all of the subjects, clinically including the control site which did not receive any material. The operated bone segments were evaluated both by radiological and histological examinations after 6 months. Radiological evaluation was carried out using bone density analysis software and histological evaluation made by light microscopy. Radiological and histological results revealed that bone grafting of oroantral osseous defects improved the bone quality. However, application of duramater did not change this activity, both alone or combined with bone grafts. Within the limits of this experimental study, although solvent-dehydrated bone grafts were found superior and could be applied for the healing of osseous oroantral defects, resorbable membranes did not contribute to this process.     

Treatment of long-standing extensive perianal hidradenitis suppurativa using double rotation plasty,V-Y plasty and free grafts

Background Perianal hidradenitis suppurativa is a chronic recurrent inflammatory, suppurating, and fistulizing disease of apocrine glands, adjacent anal canal skin, and soft tissues. The standard treatment used for extensive cases is a staged surgical procedure allowing the wound to heal by secondary intention or the delayed use of skin grafts.Case presentation A long-standing case, disabling for the patient, with extensive involvement of the buttock region, treated in one stage, which for reconstruction required the use of sliding plasties and free skin grafts, is reported.Results The outcome was satisfactory. Primary closure after wide excision using plastic-surgery techniques may help us resolve complex situations and obtain good results and a rapid recovery.Conclusion The method of closure with a combination of skin flaps and skin graft in one stage can be considered a valid surgical option for a group of patients with extensive perianal hidradenitis.     

Effect of sustained heparin release from PCL/chitosan hybrid small-diameter vascular grafts on anti-thrombogenic property and endothelialization

Thrombus formation and subsequent occlusion are the main reasons for the failure of small-diameter vascular grafts. In this study, a hybrid small-diameter vascular graft was developed from synthetic polymer poly(ε-caprolactone) (PCL) and natural polymer chitosan (CS) by the co-electrospinning technique. Heparin was immobilized on the grafts through ionic bonding between heparin and CS fibers. The immobilization was relatively stable, and heparin could continuously release from the grafts for more than 1 month. Heparin functionalization evidently improved the hemocompatibility of the PCL/CS vascular grafts, which was illustrated by the reduced platelet adhesion and prolonged coagulation time (activated partial thromboplastin time, prothrombin time and thromboplastin time) as shown in the human plasma assay, and was further confirmed by the ex vivo arteriovenous shunt experiment. In vitro cell proliferation assay showed that heparin can promote the growth of human umbilical vein endothelial cells, while moderately inhibiting the proliferation of vascular smooth muscle cells, a main factor for neointimal hyperplasia. Implantation in rat abdominal aorta was performed for 1 month. Results indicate that sustained release of heparin provided optimal anti-thrombogenic effect by reducing thrombus formation and maintaining the patency. Furthermore, heparin functionalization also enhanced in situ endothelialization, thereby preventing the occurrence of restenosis. In conclusion, it provides a facile and useful technique for the development of heparinized medical devices, including vascular grafts.     

Long-term outcomes using vascular grafts sealed with fragmented autologous adipose tissue for aortoiliac occlusive disease

The aim of this study was to test the safety and efficacy of fragmented autologous adipose tissue (FAT) grafts for revascularization in aortoiliac occlusive disease. Twenty-seven patients with atherosclerotic aortoiliac occlusive disease underwent surgical treatment using FAT grafts. A piece of adipose connective tissue was obtained from the operative wound, cut into small pieces, and pressed into the wall of a fabric vascular prosthesis. Cumulative primary patency rates were 92% at 1 year, 92% at 3 years, and 86% at 6 years. Cumulative secondary patency rates were 96%, 96%, and 90% for the same intervals. In this clinical study, the FAT grafts demonstrated good long-term patency rates and no particular problems. This is the first clinical report of long-term outcomes using FAT grafts for aortofemoral or aortoiliac bypasses. FAT grafts are thus safe for revascularization in aortoiliac occlusive disease.     

Mycobacterium fortuitum keratitis

We report a case of mycobacterial keratitis characterized by apparently spontaneous onset, delayed diagnosis, and eventually necessitating evisceration inspite of systemic antibiotics and repeated corneal grafts.     

Suture-reinforced electrospun polydioxanone-elastin small-diameter tubes for use in vascular tissue engineering: a feasibility study

This study characterizes the cross-linking of electrospun elastin and the mechanical properties of suture-reinforced 1.5mm internal diameter electrospun tubes composed of blended polydioxanone (PDO) and soluble elastin. Several tube configurations were tested to assess the effects of reinforcement on tube mechanical properties. Between the electrospun layers of each double-layered prosthetic, zero, one or two 6-0 sutures were wound, maintaining 1mm spacing with a pitch of 9 degrees . Single-layered tubes without suture were also examined. Samples were cross-linked and tested for compliance and burst strength. Compliance decreased significantly (p <0.05) and burst strength significantly increased (p <0.01) with reinforcement. Uncross-linked tubes were also tested to determine the effects of cross-linking. Results demonstrated that cross-linking significantly decreases burst strength (p <0.01), while decreases in compliance for cross-linked tubes were not significant. Cross-linked suture-reinforced PDO-elastin tubes had burst pressures more than 10 times greater than normal systolic pressures and exhibited a range of compliance values, including those matching native artery. These tubes display many characteristics of the "ideal" small-diameter graft, having mechanical properties that can be tailored to match those desired in vascular replacement applications.     

Points to consider when evaluating three-dimensional digital subtraction angiography of intracranial aneurysms and their effects on treatment

Background/aimIn this study, we aimed to investigate what should be regarded as potential determinants of treatment strategies when evaluating 3D digital subtraction angiography (DSA) images.Material and methodsOur inclusion criteria were as follows: (1) presence of at least one intracranial aneurysm demonstrated by conventional angiography, (2) having both 2D and 3D images, and (3) being over 18 years old. First, two-dimensional (2D) and then 3D angiography images of 226 aneurysms of 150 patients were scanned. Morphological characteristics such as size, configurations, relationship with parent artery, baby counts, and other incidental findings were determined.ResultsOf the 226 aneurysms, 11 (4.9%) were only detected on 3D images. Four of these 11 additional aneurysms were believed to be babies of other aneurysms seen in 2D images. Middle cerebral artery (MCA) M1 segment was the most common localization in terms of missed aneurysms. Of the 28 aneurysms located in the communicating segment of the internal carotid artery, the absolute locations of 7 (25%) could not be detected in 2D images or detected in the wrong location. Of the 24 aneurysms located in the ophthalmic segment, the origin of 8 (33%) could not be clearly identified in 2D images. Truncus relationships of MCAs bifurcation/trifurcation aneurysms were seen in 41 of 63 aneurysms (65%) on 2D images, whereas all were confirmed on 3D images. Fenestrations not seen in 2D images were identified in 3D images of 4 patients (3%).ConclusionThe superiority of 3D images compared to 2D images in determining the morphologic characteristics of intracranial aneurysms has been known for a long time. The contribution of 3D images to the treatment can be summarized as evaluating the parent artery relationship, revealing the number and shapes of aneurysm babies more clearly, detecting fenestrations, and shortening procedure time by finding the correct working angle.     

Nerve regeneration and elastin formation within poly(glycerol sebacate)-based synthetic arterial grafts one-year post-implantation in a rat model

The objective of this study was to evaluate the long-term performance of cell-free vascular grafts made from a fast-degrading elastic polymer. We fabricated small arterial grafts from microporous tubes of poly(glycerol sebacate) (PGS) reinforced with polycaprolactone (PCL) nanofibers on the outer surface. Grafts were interpositioned in rat abdominal aortas and characterized at 1 year post-implant. Grafts remodeled into “neoarteries” (regenerated arteries) with similar gross appearance to native rat aortas. Neoarteries mimic arterial tissue architecture with a confluent endothelium and media and adventita-like layers. Patent vessels (80%) showed no significant stenosis, dilation, or calcification. Neoarteries contain nerves and have the same amount of mature elastin as native arteries. Despite some differences in matrix organization, regenerated arteries had similar dynamic mechanical compliance to native arteries in vivo. Neoarteries responded to vasomotor agents, albeit with different magnitude than native aortas. These data suggest that an elastic vascular graft that resorbs quickly has potential to improve the performance of vascular grafts used in small arteries. This design may also promote constructive remodeling in other soft tissues.     

Regulation of human endothelial progenitor cell maturation by polyurethane nanocomposites

The mobilization and homing of endothelial progenitor cells (EPCs) are critical to the development of an antithrombotic cardiovascular prosthesis. Polyurethane (PU) with superior elasticity may provide a mechanical environment resembling that of the natural vascular tissues. The topographical cues of PU were maximized by making nanocomposites with a small amount of gold nanoparticles (AuNPs). The nanocomposites of PU-AuNPs (“PU-Au”) with a favorable response of endothelial cells were previously established. In the current study, the effect of PU and PU-Au nanocomposites on the behavior of human peripheral blood EPCs was investigated in vitro and in vivo. It was found that PU-Au promoted EPCs to become differentiated endothelial cells in vitro, confirmed by the increased expressions of CD31 and VEGF-R2 surface markers. The increased maturation of EPCs was significantly more remarkable on PU-Au, probably through the stromal derived factor 1α (SDF-1α)/CXCR4 signaling pathway. In vivo experiments showed that EPCs seeded on PU-Au coated catheters effectively reduced thrombosis by differentiation into endothelial cells. Surface endothelialization with CD31 and CD34 expression as well as intimal formation with α-SMA expression was significantly accelerated in the group receiving EPC-seeded PU-Au catheters. Moreover, the analysis of collagen deposition revealed a reduction of fibrosis in the group receiving EPC-seeded PU-Au catheters as compared to the other groups. These results suggest that EPCs engineered with a proper elastic substrate may provide unique endothelialization and antithrombogenic properties that benefit vascular tissue regeneration.     

Electrospun scaffolds for tissue engineering of vascular grafts

There is a growing demand for off-the-shelf tissue engineered vascular grafts (TEVGs) for the replacement or bypass of damaged arteries in various cardiovascular diseases. Scaffolds from the decellularized tissue skeletons to biopolymers and biodegradable synthetic polymers have been used for fabricating TEVGs. However, several issues have not yet been resolved, which include the inability to mimic the mechanical properties of native tissues, and the ability for long-term patency and growth required for in vivo function. Electrospinning is a popular technique for the production of scaffolds that has the potential to address these issues. However, its application to human TEVGs has not yet been achieved. This review provides an overview of tubular scaffolds that have been prepared by electrospinning with potential for TEVG applications.