Biomedical subjects

Byung Chul Chang

Publications and source records attributed to Byung Chul Chang.

5 recordsLinked to original sources

PubMed2006

Tissue engineering of heart valves by recellularization of glutaraldehyde-fixed porcine valves using bone marrow-derived cells.

To increase the biocompatibility and durability of glutaraldehyde (GA)-fixed valves, a biological coating with viable endothelial cells (ECs) has been proposed. However, stable EC layers have not been formed successfully on GA-fixed valves due to their inability to repopulate. In this study, to improve cellular adhesion and proliferation, the GA-fixed prostheses were detoxified by treatment with citric acid to remove free aldehyde groups. Canine bone marrow mononuclear cells (MNCs) were differentiated into EC-like cells and myofibroblast-like cells in vitro. Detoxified prostheses were seeded and recellularized with differentiated bone marrow- derived cells (BMCs) for seven days. Untreated GA-fixed prostheses were used as controls. Cell attachment, proliferation, metabolic activity, and viability were investigated and cell-seeded leaflets were histologically analyzed. On detoxified GA-fixed prostheses, BMC seeding resulted in uninhibited cell proliferation after seven days. In contrast, on untreated GA-fixed prostheses, cell attachment was poor and no viable cells were observed. Positive staining for smooth muscle a-actin, CD31, and proliferating cell nuclear antigen was observed on the luminal side of the detoxified valve leaflets, indicating differentiation and proliferation of the seeded BMCs. These results demonstrate that the treatment of GA-fixed valves with citric acid established a surface more suitable for cellular attachment and proliferation. Engineering heart valves by seeding detoxified GA-fixed biological valve prostheses with BMCs may increase biocompatibility and durability of the prostheses. This method could be utilized as a new approach for the restoration of heart valve structure and function in the treatment of end-stage heart valve disease.

Actins↗

PubMed2006

Stent-graft treatment of infected aortic and arterial aneurysms.

PURPOSE: To evaluate the feasibility and effectiveness of endovascular stent-graft repair of infected aortic and arterial aneurysms. METHODS: Eight patients (5 men; mean age 56.6 years, range 30-85) with infected saccular aneurysms in the brachiocephalic artery (n=1), proximal descending thoracic aorta (n=1), infrarenal abdominal aorta (n=3), common iliac artery (n=1), and common femoral artery (n=2) were treated with stent-graft placement and intravenous antibiotic treatment for at least 6 weeks followed by case-specific administration of oral suppressive antibiotics. All patients were considered to be in the high-surgical-risk group. RESULTS: Exclusion of the infected aneurysm was successful in all patients. However, 2 patients died within 30 days of uncontrolled sepsis, and 1 patient died at 6 months after rupture of a persistently infected aneurysm (37% mortality rate). Over a follow-up that ranged to 8 years, the 5 survivors showed complete resolution of the infected aneurysms; no stent-graft infection was observed during follow-up. CONCLUSION: The acceptable technical and clinical success of endovascular aneurysm repair makes this a promising treatment for infected aortic and arterial aneurysms. However, it is crucial that the infection is treated adequately prior to stent-graft placement.

Adult↗

PubMed2005

Small-diameter blood vessels engineered with bone marrow-derived cells.

OBJECTIVE: The objective of this study is to investigate if bone marrow-derived cells (BMCs) regenerate vascular tissues and improve patency in tissue-engineered small-diameter (internal diameter = 3 mm) vascular grafts. SUMMARY BACKGROUND DATA: BMCs have demonstrated the ability to differentiate into endothelial-like cells and vascular smooth muscle-like cells and may offer an alternative cell source for vascular tissue engineering. Thus, we tissue-engineered small-diameter vascular grafts with BMCs and decellularized arteries. METHODS: Canine BMCs were differentiated in vitro into smooth muscle alpha-actin/smooth muscle myosin heavy-chain-positive cells and von Willebrand factor/CD31-positive cells and seeded onto decellularized canine carotid arteries (internal diameter = 3 mm). The seeded grafts were implanted in cell donor dogs. The vascular-tissue regeneration and graft patency were investigated with immunohistochemistry and angiography, respectively. RESULTS: The vascular grafts seeded with BMCs remained patent for up to 8 weeks in the canine carotid artery interposition model, whereas nonseeded grafts occluded within 2 weeks. Within 8 weeks after implantation, the vascular grafts showed regeneration of the 3 elements of artery (endothelium, media, and adventitia). BMCs labeled with a fluorescent dye prior to implantation were detected in the retrieved vascular grafts, indicating that the BMCs participated in the vascular tissue regeneration. CONCLUSIONS: Here we show that BMCs have the potential to regenerate vascular tissues and improve patency in tissue-engineered small-diameter vascular grafts. This is the first report of a small-diameter neovessel engineered with BMCs as a cell source.

Animals↗

PubMed2004

Elective stent-graft treatment of aortic dissections.

PURPOSE: To retrospectively review 8 years' experience with stent-graft treatment of aortic dissections at a single institution. METHODS: Forty-six patients (31 men; mean age 59 years, range 38-88) underwent stent-graft treatment for 9 Stanford type A and 37 type B aortic dissections (9 acute phase, 13 subacute, 24 chronic). Custom-designed self-expanding stainless steel Z stents covered with polytetrafluoroethylene were used (n=20) until low-profile modular stent-grafts became available for percutaneous delivery (n=26). RESULTS: Endovascular stent-graft deployment was technically successful in 44 (96%) patients; the 2 failed cases owing to intraprocedural migration and graft torsion were converted to surgery. There were 5 type I endoleaks for a clinical success (entry tear exclusion) of 85% (39/46). Complications included 3 cases of transient renal failure, 2 puncture site pseudoaneurysms, 1 guidewire-induced new intimal tear (converted), and 2 cases of stent-induced saccular aneurysms (1 converted). Follow-up at a mean 34 months (range 12-96) showed complete resolution of the thoracic false lumen in 14 (74%) of 19 acute/subacute patients treated successfully; 3 (16%) showed a reduced thoracic false lumen diameter. In the 23 chronic-phase patients treated successfully, 8 (35%) had complete resolution of the thoracic false lumen, and 11 (48%) showed size reduction. Enlargement of the abdominal aortic false lumen due to persistent flow into re-entry tear(s) occurred in 3 (13%). CONCLUSIONS: Stent-graft treatment is a feasible and effective treatment modality in aortic dissection. However, close follow-up is mandatory to monitor new intimal tear, saccular aneurysms, or enlargement of the abdominal aortic false lumen.

Adult↗

PubMed2003

False aneurysms at both ends of a descending thoracic aortic stent-graft: complication after endovascular repair of a penetrating atherosclerotic ulcer.

PURPOSE: To report the formation of false aneurysms at both ends of a stent-graft implanted in the descending thoracic aorta to repair a penetrating atherosclerotic ulcer. CASE REPORT: A 66-year-old woman with a penetrating atherosclerotic ulcer was treated with a 34 x 70-mm homemade Gianturco-type stent covered with polytetrafluoroethylene graft. Four months later, she developed false aneurysms at both ends of the stent-graft. The patient refused further endovascular repairs, so the stent-graft was surgically removed and the aorta repaired. CONCLUSIONS: This case demonstrates an unusual complication that should be anticipated when a stent-graft is deployed in the acute phase of thoracic aortic ulcer or its variants.

Aged↗