Hiroshi Kurazumi

The effects of mechanical stress on the growth, differentiation, and paracrine factor production of cardiac stem cells

Stem cell therapies have been clinically employed to repair the injured heart, and cardiac stem cells are thought to be one of the most potent stem cell candidates. The beating heart is characterized by dynamic mechanical stresses, which may have a significant impact on stem cell therapy. The purpose of this study is to investigate how mechanical stress affects the growth and differentiation of cardiac stem cells and their release of paracrine factors. In this study, human cardiac stem cells were seeded in a silicon chamber and mechanical stress was then induced by cyclic stretch stimulation (60 cycles/min with 120% elongation). Cells grown in non-stretched silicon chambers were used as controls. Our result revealed that mechanical stretching significantly reduced the total number of surviving cells, decreased Ki-67-positive cells, and increased TUNEL-positive cells in the stretched group 24 hrs after stretching, as compared to the control group. Interestingly, mechanical stretching significantly increased the release of the inflammatory cytokines IL-6 and IL-1β as well as the angiogenic growth factors VEGF and bFGF from the cells in 12 hrs. Furthermore, mechanical stretching significantly reduced the percentage of c-kit-positive stem cells, but increased the expressions of cardiac troponin-I and smooth muscle actin in cells 3 days after stretching. Using a traditional stretching model, we demonstrated that mechanical stress suppressed the growth and proliferation of cardiac stem cells, enhanced their release of inflammatory cytokines and angiogenic factors, and improved their myogenic differentiation. The development of this in vitro approach may help elucidate the complex mechanisms of stem cell therapy for heart failure.

Laparoscopic resection of an ileal lipoma : Report of a case

A 63-year-old woman was admitted to our hospital for investigation of upper abdominal pain and vomiting. Ultrasonography (US) showed a hyperechoic mass in the right lower abdomen, and computed tomography (CT) showed a low-density mass and intestinal invagination. Thus, we made a diagnosis of intestinal lipoma with intussusception and performed laparoscopic partial resection of the ileum, including the tumor. The resected specimen contained a round tumor, 25 × 22 × 20 mm, which was identified as an intestinal lipoma histopathologically. Our experience supports earlier reports that US and CT are effective tools in the diagnosis of bowel lipoma. Laparoscopic surgery is the treatment of choice for benign tumors of the small intestine because it is minimally invasive, with cosmetic, physical, and economic benefits.

Laparoscopic cecopexy for mobile cecum syndrome manifesting as cecal volvulus: Report of a case

A 44-year-old woman was admitted to our hospital for investigation and treatment of sudden abdominal pain and distention. Plain abdominal radiography and abdominal computed tomography (CT) findings were suggestive of sigmoid volvulus. She underwent an emergency colonoscopy, and the scope passed easily through the sigmoid colon and reached the ascending colon quickly. However, stenosis with concentricity of the fold was observed in the cecum, which was shifted upward and to the left. Based on these findings, we diagnosed cecal volvulus caused by mobile cecum syndrome. The patient’s symptoms resolved quickly after colonoscopic reduction and elective laparoscopic surgery was performed 18 days after admission. Perioperative examination revealed a mobile cecum caused by an elongated ascending colon. We sutured the cecum and ascending colon to the lateral peritoneum laparoscopically with interrupted sutures. The patient recovered well and was discharged on postoperative day 7. An unfixed intestine can be detected easily during laparoscopic surgery, which is minimally invasive and cosmetically, physically, and economically beneficial. Thus, we recommend laparoscopic cecopexy for mobile cecum syndrome.

Secondary omental and pectoralis major double flap reconstruction following aggressive sternectomy for deep sternal wound infections after cardiac surgery

BackgroundDeep sternal wound infection after cardiac surgery carries high morbidity and mortality. Our strategy for deep sternal wound infection is aggressive strenal debridement followed by vacuum-assisted closure (VAC) therapy and omental-muscle flap reconstrucion. We describe this strategy and examine the outcome and long-term quality of life (QOL) it achieves.MethodsWe retrospectively examined 16 patients treated for deep sternal wound infection between 2001 and 2007. The most recent nine patients were treated with total sternal resection followed by VAC therapy and secondary closure with omental-muscle flap reconstruction (recent group); whereas the former seven patients were treated with sternal preservation if possible, without VAC therapy, and four of these patients underwent primary closure (former group). We assessed long-term quality of life after DSWI by using the Short Form 36-Item Health Survey, Version 2 (SF36v2).ResultsOne patient died and four required further surgery for recurrence of deep sternal wound infection in the former group. The duration of treatment for deep sternal wound infection in the recent group was significantly shorter than that in previous group (63.4 ± 54.1 days vs. 120.0 ± 31.8 days, respectively; p = 0.039). Despite aggressive sternal resection, the QOL of patients treated for DSWI was only minimally compromised compared with age-, sex-, surgical procedures-matched patients without deep sternal wound infection.ConclusionsAggressive sternal debridement followed by VAC therapy and secondary closure with an omental-muscle flap is effective for deep sternal wound infection. In this series, it resulted in a lower incidence of recurrent infection, shorter hospitalization, and it did not compromise long-term QOL greatly.

Mitral-valve replacement for a severely calcified mitral annulus: a simple and novel technique

Systemic calcifications are often seen in patients with end-stage renal failure, who need long-term hemodialysis. When patients with severe calcification of the mitral-valve annulus undergo mitral-valve replacement (MVR), complete debridement of the calcified tissues may result in fatal complications such as rupture of the left ventricle or injury to the coronary artery. We describe a novel technique of MVR for a severely calcified mitral annulus and leaflet, in which only the anterior leaflet is excised, preserving the posterior leaflet to prevent fatal complications. We passed 2/0 polyester mattress sutures through the mitral annulus from the left ventricle to the left atrium and fixed the preserved posterior leaflet to the posterior mitral annulus and prosthetic valve. The mitral valve was replaced using a St. Jude Medical mechanical heart valve with a specific structure and a hinge that shifts to the left atrial side and most of the leaflet moves within its housing. This structure enables this procedure to be performed without the excision of a severely calcified posterior mitral leaflet and annulus. Our technique may prevent the fatal complications that can be caused by debridement or excision of severely calcified mitral apparatus.

Early laparoscopic cholecystectomy for acute gangrenous cholecystitis.

Treatment of severe acute cholecystitis by laparoscopic cholecystectomy remains controversial because of technical difficulties and high rates of complications and conversion to open cholecystectomy. We investigated whether early laparoscopic cholecystectomy is appropriate for acute gangrenous cholecystitis. Pathologic diagnoses and outcomes were analyzed in patients who underwent laparoscopic or open cholecystectomy at our hospital, January 2002 to September 2005. Of 30 patients with acute gangrenous cholecystitis, 16 underwent early laparoscopic cholecystectomy, 10 underwent open cholecystectomy, and 4 were converted to open cholecystectomy (conversion rate, 20.0%). There was no significant difference in operation time or intraoperative bleeding. The requirement for postoperative analgesics was significantly lower (6.4±7.3 vs. 1.5±1.2 doses, P<0.05) and hospital stay significantly shorter (8.6±2.1 vs. 15.6±6.3 d, P<0.01) after laparoscopic cholecystectomy. There were no postoperative complications in either group. Thus, early laparoscopic cholecystectomy seems appropriate for acute gangrenous cholecystitis. Conversion to open cholecystectomy may be required in difficult cases with complications.

Aortic arch surgery in octogenarians: is it justified?

OBJECTIVES Elderly patients are sometimes denied aortic arch surgery because of the perception of poor outcomes and an unacceptable quality of life (QOL). In this study, we evaluated the early clinical outcomes, long-term survival and QOL following surgical treatment for aortic arch disease in octogenarian patients. METHODS A total of 47 consecutive patients over the age of 80 years were referred to our institutions. Of these patients, 20 underwent surgical intervention (surgical group) and 27 were treated medically (medical group). Kaplan-Meier survival analysis was performed between the two groups, and the results were compared with age-matched population data. The risk factors for mortality were determined using a Cox regression analysis. A QOL assessment was performed using the 36-item Short Form Health Survey. RESULTS The patient characteristics at baseline were not significantly different between the two groups. In the surgical cases, conventional total aortic arch replacement was performed in 15 patients, debranched thoracic endovascular aortic repair (TEVAR) in 2 and chimney TEVAR in 3. Emergency procedures were performed in 3 patients. No hospital deaths occurred in the surgical groups. Reoperation for bleeding was required in 2 patients, and prolonged mechanical ventilation was required in 4 patients. The 5-year survival was 61.5% in the surgical group and 14.2% in the medical group (P = 0.02). Freedom from aorta-related death at 5 years was 92.3% in the surgical group and 32.3% in the medical group (P = 0.01). There were no differences in the 5-year survival between patients undergoing surgical intervention and the sex- and age-matched population (P = 0.80), whereas the 5-year survival was significantly lower in patients who received medical therapy relative to the sex- and age-matched population (P < 0.001). Medical therapy was the sole risk factor for mortality (hazard ratio: 3.16, P = 0.04). Among the survivors at mid-term, the quality-of-life measures were similar between those in the surgical group and those in the medical group. CONCLUSIONS Surgical intervention for aortic arch disease in octogenarians can yield satisfactory early clinical outcomes and acceptable mid-term survival with adequate daily activity. This study indicates that among octogenarians, age alone should not disqualify a patient from receiving an aortic arch intervention.

Diabetic Impairment of C-Kit+ Bone Marrow Stem Cells Involves the Disorders of Inflammatory Factors, Cell Adhesion and Extracellular Matrix Molecules

Bone marrow stem cells from diabetes mellitus patients exhibit functional impairment, but the relative molecular mechanisms responsible for this impairment are poorly understood. We investigated the mechanisms responsible for diabetes-related functional impairment of bone marrow stem cells by extensively screening the expression levels of inflammatory factors, cell cycle regulating molecules, extracellular matrix molecules and adhesion molecules. Bone marrow cells were collected from type 2 diabetic (db/db) and healthy control (db/m+) mice, and c-kit+ stem cells were purified (purity>85%) for experiments. Compared with the healthy control mice, diabetic mice had significantly fewer c-kit+ stem cells, and these cells had a lower potency of endothelial differentiation; however, the production of the angiogenic growth factor VEGF did not differ between groups. A pathway-focused array showed that the c-kit+ stem cells from diabetic mice had up-regulated expression levels of many inflammatory factors, including Tlr4, Cxcl9, Il9, Tgfb1, Il4, and Tnfsf5, but no obvious change in the expression levels of cell cycle molecules. Interestingly, diabetes-related alterations of the extracellular matrix and adhesion molecules were varied; Pecam, Mmp10, Lamc1, Itgb7, Mmp9, and Timp4 were up-regulated, but Col11a1, Fn1, Admts2, and Itgav were down-regulated. Some of these changes were also confirmed at the protein level by flow cytometry analysis. In conclusion, c-kit+ bone marrow stem cells from diabetic mice exhibited an extensive enhancement of inflammatory factors and disorders of the extracellular matrix and adhesion molecules. Further intervention studies are required to determine the precise role of each molecule in the diabetes-related functional impairment of c-kit+ bone marrow stem cells.

Influence of aging on the quantity and quality of human cardiac stem cells.

Advanced age affects various tissue-specific stem cells and decreases their regenerative ability. We therefore examined whether aging affected the quantity and quality of cardiac stem cells using cells obtained from 26 patients of various ages (from 2 to 83 years old). We collected fresh right atria and cultured cardiosphere-derived cells (CDCs), which are a type of cardiac stem cell. Then we investigated growth rate, senescence, DNA damage, and the growth factor production of CDCs. All samples yielded a sufficient number of CDCs for experiments and the cellular growth rate was not obviously associated with age. The expression of senescence-associated b-galactosidase and the DNA damage marker, gH2AX, showed a slightly higher trend in CDCs from older patients (≥65 years). The expression of VEGF, HGF, IGF-1, SDF-1, and TGF-b varied among samples, and the expression of these beneficial factors did not decrease with age. An in vitro angiogenesis assay also showed that the angiogenic potency of CDCs was not impaired, even in those from older patients. Our data suggest that the impact of age on the quantity and quality of CDCs is quite limited. These findings have important clinical implications for autologous stem cell transplantation in elderly patients.

Heat shock factor 1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of bone marrow stem/progenitor cells.

Bone marrow (BM)-derived stem/progenitor cells play an important role in ischemia-induced angiogenesis in cardiovascular diseases. Heat shock factor 1 (HSF1) is known to be induced in response to hypoxia and ischemia. We examined whether HSF1 contributes to ischemia-induced angiogenesis through the mobilization and recruitment of BM-derived stem/progenitor cells using HSF1-knockout (KO) mice. After the induction of ischemia, blood flow and microvessel density in the ischemic hindlimb were significantly lower in the HSF1-KO mice than in the wild-type (WT) mice. The mobilization of BM-derived Sca-1- and c-kit-positive cells in peripheral blood after ischemia was significantly lower in the HSF1-KO mice than in the WT mice. BM stem/progenitor cells from HSF1-KO mice showed a significant decrease in their recruitment to ischemic tissue and in migration, adhesion, and survival when compared with WT mice. Blood flow recovery in the ischemic hindlimb significantly decreased in WT mice receiving BM reconstitution with donor cells from HSF1-KO mice. Conversely, blood flow recovery in the ischemic hindlimb significantly increased in HSF1-KO mice receiving BM reconstitution with donor cells from WT mice. These findings suggest that HSF1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of BM-derived stem/progenitor cells.