Go Kuwahara

Oriented Collagen Scaffolds for Tissue Engineering

Oriented collagen scaffolds were developed in the form of sheet, mesh and tube by arraying flow-oriented collagen string gels and dehydrating the arrayed gels. The developed collagen scaffolds can be any practical size with any direction of orientation for tissue engineering applications. The birefringence of the collagen scaffolds was quantitatively analyzed by parallel Nicols method. Since native collagen in the human body has orientations such as bone, cartilage, tendon and cornea, and the orientation has a special role for the function of human organs, the developed various types of three-dimensional oriented collagen scaffolds are expected to be useful biomaterials for tissue engineering and regenerative medicines.

Two-layer tissue engineered urethra using oral epithelial and muscle derived cells.

PURPOSE We fabricated novel tissue engineered urethral grafts using autologously harvested oral cells. We report their viability in a canine model. MATERIALS AND METHODS Oral tissues were harvested by punch biopsy and divided into mucosal and muscle sections. Epithelial cells from mucosal sections were cultured as epithelial cell sheets. Simultaneously muscle derived cells were seeded on collagen mesh matrices to form muscle cell sheets. At 2 weeks the sheets were joined and tubularized to form 2-layer tissue engineered urethras, which were autologously grafted to surgically induced urethral defects in 10 dogs in the experimental group. Tissue engineered grafts were not applied to the induced urethral defect in control dogs. The dogs were followed 12 weeks postoperatively. Urethrogram and histological examination were done to evaluate the grafting outcome. RESULTS We successfully fabricated 2-layer tissue engineered urethras in vitro and transplanted them in dogs in the experimental group. The 12-week complication-free rate was significantly higher in the experimental group than in controls. Urethrogram confirmed urethral patency without stricture in the complication-free group at 12 weeks. Histologically urethras in the transplant group showed a stratified epithelial layer overlying well differentiated submucosa. In contrast, urethras in controls showed severe fibrosis without epithelial layer formation. CONCLUSIONS Two-layer tissue engineered urethras were engineered using cells harvested by minimally invasive oral punch biopsy. Results suggest that this technique can encourage regeneration of a functional urethra.

Vascular endothelial growth factor-C derived from CD11b+ cells induces therapeutic improvements in a murine model of hind limb ischemia

OBJECTIVE The use of bone marrow cells (BMCs) in therapeutic angiogenesis has been studied extensively. However, the critical paracrine effects of this treatment are still unclear. Therefore, we studied autotransfusable cells that produce vascular endothelial growth factor (VEGF), especially VEGF-C. METHODS Male C57BL/6 mice with hind limb ischemia were administered intramuscular injections of phosphate-buffered saline as controls, or unsorted BMCs, sorted CD11b(+), or CD11b(-) cells from BMCs, and recombinant VEGF-C. To evaluate the treatments, perfusion was measured by laser Doppler scanning performed on days 0, 1, 3, 7, 14, 21, and 28. A functional assay was performed in parallel, with mice traversing an enclosed walkway. Capillary density was determined by directly counting vessels stained positive with von Willebrand factor at individual time points. Lymphangiogenesis was assessed by LYVE-1 positive cells. RESULTS Postischemic recovery of hind limb perfusion significantly improved in BMC, CD11b(+), and VEGF-C treatment groups compared with the control groups, as assessed by laser Doppler scanning. On early operative days 1 and 3, the blood flow recovery ratio was higher in the CD11b(+)-treated group compared with BMC and VEGF-C treatment groups. In the functional assay, the VEGF-C group dramatically recovered compared with the control group. The capillary/myofiber ratio in the thigh muscle and number of LYVE-1 positive cells was higher in the CD11b(+) and VEGF-C groups than in controls. Furthermore, expression of VEGF-A, VEGF-C, and VEGF receptor messenger ribonucleic acid and protein was observed in CD11b(+) cells. CONCLUSIONS The VEGF-C derived from CD11b(+) cells play a critical role in angiogenesis and lymphangiogenesis in a murine model of hind limb ischemia. Consequently, treatment with self-CD11b(+) cells accelerated recovery from ischemia and may be a promising therapeutic strategy for peripheral arterial disease patients.

Endoscopic Radial Artery Harvesting for Coronary Artery Bypass Grafting: The Initial Clinical Experience and Results of the First 50 Patients

BACKGROUND The radial artery (RA) is a commonly used arterial conduit in coronary artery bypass grafting (CABG). Traditional open-vessel harvest often leads to postoperative wound complications and cosmetic problems. Endoscopic RA harvesting (ERAH) has been widely used to prevent these problems. The purpose of this study was to assess these problems and graft patency in the first 50 patients who underwent ERAH. METHODS Between February 2006 and October 2007, 50 patients underwent ERAH with the VasoView system (Boston Scientific). These patients were compared with 50 patients who underwent the traditional open technique. RESULTS The mean age was 62.8 years in both groups. All RAs were successfully harvested. No conversion was made from ERAH to the traditional open technique. The mean harvesting time (forearm ischemic time) was 27.4 + or - 6.5 minutes, and the mean length of the RA in the ERAH group was 18.5 cm. Neither wound complications, such as wound infection and skin necrosis, nor severe neurologic complications were recorded. The patency rate was 95.9% (95/99) in the ERAH group and 94% (94/100) in the open group. CONCLUSION ERAH can be performed safely, and the early results are satisfactory. Endoscopic vessel harvesting is therefore recommended as the technique of choice for RA harvesting.

Segmental arterial mediolysis accompanied by renal infarction and pancreatic enlargement: a case report

IntroductionDue to recent advances in imaging diagnostic techniques, there are an increasing number of case reports of segmental arterial mediolysis. However, there are only a limited number of reports on segmental arterial mediolysis-related abnormalities of abdominal organs other than the intestine. This report describes a case of segmental arterial mediolysis accompanied by abnormalities of abdominal organs without clinical symptoms.Case presentationA 52-year-old Japanese man with hematuria and no prior medical history was referred to a urologist and was diagnosed as having urinary bladder cancer. He underwent trans-urethral resection of the bladder tumor and intra-vesical instillation therapy, which was followed by observation. During follow-up, although no abdominal symptoms were observed, an abdominal computed tomography scan revealed a dissection of the superior mesenteric artery. A false lumen partially occluded by a thrombus was located distal to this occlusion. The lumen was irregularly shaped with narrow and wide sections. Similar irregularities were also observed in the wall of the inferior mesenteric artery. Arterial dissection with thromboembolism in the left renal artery and renal infarction was also observed. Follow-up computed tomography after two months revealed an enlargement of the pancreatic tail adjacent to the splenic artery. Follow-up three-dimensional computed tomography showed gradual re-expansion of the true lumen of the superior mesenteric artery, improvement in arterial wall irregularities, and a reduction in the pancreas enlargement and renal infarction. Over the following 15 months, these changes gradually normalized. On the basis of the vascular changes in multiple arterial systems that resolved spontaneously, we considered that the lesions were associated with segmental arterial mediolysis.ConclusionsWe present a rare case of segmental arterial mediolysis accompanied by abnormalities of abdominal organs without clinical symptoms. Three-dimensional computed tomography was useful for follow-up evaluation in our patient.

GM-CSF Treated F4/80+ BMCs Improve Murine Hind Limb Ischemia Similar to M-CSF Differentiated Macrophages

Novel cell therapy is required to treat critical limb ischemia (CLI) as many current approaches require repeated aspiration of bone marrow cells (BMCs). The use of cultured BMCs can reduce the total number of injections required and were shown to induce therapeutic angiogenesis in a murine model of hind limb ischemia. Blood flow recovery was significantly improved in mice treated with granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent BMCs that secreted inflammatory cytokines. Angiogenesis, lymphangiogenesis, and blood flow recovery ratio were significantly higher in the GM-CSF-cultured F4/80+ macrophage (GM-Mø)-treated group compared with controls. Furthermore, Foxp3+ cell numbers and tissue IL-10 concentrations were significantly increased compared with controls. There was no significant difference in blood flow recovery between GM-Mø and M-CSF-cultured F4/80+ macrophages (M-Mø). Thus, GM-Mø were associated with improved blood flow in hind limb ischemia similar to M-Mø. The selective methods of culturing and treating GM-Mø cells similar to M-Mø cells could be used clinically to help resolve the large number of cells required for BMC treatment of CLI. This study demonstrates a novel cell therapy for CLI that can be used in conjunction with conventional therapy including percutaneous intervention and surgical bypass.

Safety and Efficacy of an Ultrashort-Acting β1-Blocker on Left Ventricular Dysfunction

Landiolol hydrochloride, an ultrashort-acting β1-selective blocker, is a highly regulated drug. This study evaluated the safety and efficacy of this drug for cases of coronary artery bypass grafting (CABG) with left ventricular dysfunction. Between September 2006 and August 2009, 32 patients with a left ventricular ejection fraction of <40% underwent CABG. Two groups of patients, a group administered landiolol hydrochloride and a control group not administered this drug, were compared. The administration of landiolol hydrochloride was initiated at 1 μg/kg per minute (γ) after cardiopulmonary bypass in on-pump cases and after completion of all the distal anastomoses in off-pump cases. We observed no significant differences between the groups with respect to preoperative patient background or incidences of complications, except for postoperative atrial fibrillation. The heart rate decreased significantly 30 minutes after landiolol hydrochloride administration, but no change was observed in arterial pressure. No change was observed in other parameters; the hemodynamics were stable. The occurrence of atrial fibrillation during the intensive care unit stay (during landiolol hydrochloride administration) was significantly lower in the administration group. The difference remained significant after multiple logistic regression analysis; landiolol hydrochloride was the sole inhibitory factor.

Efficacy of Propafenone Hydrochloride in Preventing Postoperative Atrial Fibrillation after Coronary Artery Bypass Grafting

BACKGROUND Atrial fibrillation (AF) is one of the most common complications after coronary artery bypass grafting (CABG), and the incidence of postoperative AF (PAF) is estimated to range from 10% to 40%. PAF is a serious complication that is related to unstable hemodynamics, development of embolisms, patient discomfort, and increased medical costs associated with the prolongation of hospital stay. Sometimes, immediate attention is also necessary. In this study, we assessed the efficacy of treatment with the antiarrhythmic drug propafenone hydrochloride, which was administered in the early postoperative period, in preventing the development of PAF, and we attempted to identify risk factors for PAF. MATERIALS AND METHODS The subjects were 78 patients who underwent isolated off-pump CABG between July 2007 and October 2008. We conducted the study by dividing the patients into 2 groups, a group of 26 patients who received propafenone hydrochloride (P group) and a control group of 52 patients who did not receive this drug (C group). The patients in the P group were given propafenone hydrochloride (150-450 mg/day orally) for 10 days, starting on the day after surgery, and were observed for the development of AF by means of continuous 12-lead electrocardiographic monitoring. Development of AF was defined as AF that lasted <or=30 minutes or as supraventricular arrhythmia that required new treatment even though it did not persist for 30 minutes. RESULTS The background factors of the patients in the P and C groups were similar. The operation times and the numbers of distal anastomoses in the 2 groups were similar, and there were no particular differences between the 2 groups with respect to postoperative factors. The incidence of PAF was 35% in the C group and significantly lower in the P group (12%, P = .0337). Moreover, multiple logistic regression analysis showed that propafenone hydrochloride was the sole factor that prevented the development of PAF (odds ratio, 0.207; 95% confidence interval, 0.053-0.804; P = .0229). CONCLUSION Cases must be carefully considered before administering propafenone hydrochloride, but the results of this study indicate that propafenone hydrochloride may prevent the development of PAF.

CD44 Promotes Inflammation and Extracellular Matrix Production During Arteriovenous Fistula Maturation

Objective— Arteriovenous fistulae (AVF) remain the optimal conduit for hemodialysis access but continue to demonstrate poor patency and poor rates of maturation. We hypothesized that CD44, a widely expressed cellular adhesion molecule that serves as a major receptor for extracellular matrix components, promotes wall thickening and extracellular matrix deposition during AVF maturation. Approach and Results— AVF were created via needle puncture in wild-type C57BL/6J and CD44 knockout mice. CD44 mRNA and protein expression was increased in wild-type AVF. CD44 knockout mice showed no increase in AVF wall thickness (8.9 versus 26.8 &mgr;m; P=0.0114), collagen density, and hyaluronic acid density, but similar elastin density when compared with control AVF. CD44 knockout mice also showed no increase in vascular cell adhesion molecule-1 expression, intercellular adhesion molecule-1 expression, and monocyte chemoattractant protein-1 expression in the AVF compared with controls; there were also no increased M2 macrophage markers (transglutaminase-2: 81.5-fold, P=0.0015; interleukin-10: 7.6-fold, P=0.0450) in CD44 knockout mice. Delivery of monocyte chemoattractant protein-1 to CD44 knockout mice rescued the phenotype with thicker AVF walls (27.2 versus 14.7 &mgr;m; P=0.0306), increased collagen density (2.4-fold; P=0.0432), and increased number of M2 macrophages (2.1-fold; P=0.0335). Conclusions— CD44 promotes accumulation of M2 macrophages, extracellular matrix deposition, and wall thickening during AVF maturation. These data show the association of M2 macrophages with wall thickening during AVF maturation and suggest that enhancing CD44 activity may be a strategy to increase AVF maturation.

A Case of Re-Endovascular Repair in Acute Phase after EndovascularAortic Repair for Acute Type B Aortic Dissection Complicated by Visceral,Renal and Lower Limb Malperfusion

We describe a case of re-endovascular aortic repair after endovascular aortic repair for acute type B aortic dissection, complicated by visceral, renal, and leg malperfusion. We performed endovascular aortic repair to cover the primary entry tear at the distal thoracic aortic arch in a 62-year-old male with visceral, renal, and leg malperfusion, after 4 days of conservative therapy. After the first operation, the pressure differential between upper and lower limbs disappeared. However, bilateral leg ischemia appeared at postoperative day 2. CT showed that the true lumen was severely compressed again by a thrombosed false lumen and two re-entries appeared at the level of the proximal celiac artery and infra-renal abdominal artery, respectively. The distal edge of the stent graft was intact with no new stent graft-induced entry. We once again performed endovascular aortic repair by means of thoracic and abdominal stent grafts covering the re-entry tears at the level of proximal celiac artery and infra-renal abdominal artery. After the procedure, the leg ischemia, renal ischemia and mesenteric ischemia improved, and the patient was transferred back to the local hospital without paraplegia.