Toshihiko Shibata

Dose-Dependent Contribution of CD34-Positive Cell Transplantation to Concurrent Vasculogenesis and Cardiomyogenesis for Functional Regenerative Recovery After Myocardial Infarction

Background— Multilineage developmental capacity of the CD34+ cells, especially into cardiomyocytes and smooth muscle cells (SMCs), is still controversial. In the present study we performed a series of experiments to prove our hypothesis that vasculogenesis and cardiomyogenesis after myocardial infarction (MI) may be dose-dependently enhanced after CD34+ cell transplantation. Methods and Results— Peripheral blood CD34+ cells were isolated from total mononuclear cells of patients with limb ischemia by apheresis after 5-day administration of granulocyte colony-stimulating factor. PBS and 1×103 (low), 1×105 (mid), or 5×105 (high) CD34+ cells were intramyocardially transplanted after ligation of the left anterior descending coronary artery of nude rats. Functional assessments with the use of echocardiography and a microtip conductance catheter at day 28 revealed dose-dependent preservation of left ventricular function by CD34+ cell transplantation. Necropsy examination disclosed dose-dependent augmentation of capillary density and dose-dependent inhibition of left ventricular fibrosis. Immunohistochemistry for human-specific brain natriuretic peptide demonstrated that human cardiomyocytes were dose-dependently observed in ischemic myocardium at day 28 (high, 2480±149; mid, 1860±141; low, 423±9; PBS, 0±0/mm2; P<0.05 for high versus mid and mid versus low). Immunostaining for smooth muscle actin and human leukocyte antigen or Ulex europaeus lectin type 1 also revealed dose-dependent vasculogenesis by endothelial cell and SMC development after CD34+ cell transplantation. Reverse transcriptase–polymerase chain reaction indicated that human-specific gene expression of cardiomyocyte (brain natriuretic peptide, cardiac troponin-I, myosin heavy chain, and Nkx 2.5), SMC (smooth muscle actin and sm22&agr;), and endothelial cell (CD31 and KDR) markers were dose-dependently augmented in MI tissue. Conclusions— Human CD34+ cell transplantation may have significant and dose-dependent potential for vasculogenesis and cardiomyogenesis with functional recovery from MI.

Risk Factor Analysis in Patients With Liver Cirrhosis Undergoing Cardiovascular Operations

BACKGROUND Variable outcomes of cardiac operations have been reported in cirrhotic patients, but no definitive predictive prognostic factors have been established. This retrospective study assessed operative results to identify risk factors associated with morbidity after cardiovascular operations in cirrhotic patients. METHODS The study comprised 42 cirrhotic patients who underwent cardiovascular operations from January 1991 to January 2009. Thirty patients were Child-Turcotte-Pugh class A, and 12 were class B. Hospital morbidity occurred in 13 patients (31.0%; M group), including 4 who died in-hospital. Patients without severe complications (N group) were compared with the M group patients. The Model for End-Stage Liver Disease (MELD) score was evaluated in 25 patients. RESULTS Significant differences in hospital morbidity between the M vs N groups were identified for platelet count (8.7 +/- 3.8 vs 12.1 +/- 4.2 x 10(4)/microL), MELD score (17.8 +/- 5.3 vs 9.8 +/- 4.9), operation time (370 +/- 88 vs 313 +/- 94 minutes), and cardiopulmonary bypass time (174 +/- 46 vs 149 +/- 53 minutes) in univariate analyses (p < 0.005). Platelet count, operation time, and age were significantly associated with hospital morbidity in multivariate analyses (p < 0.005). Platelet count of 9.6 x 10(4)/microL and MELD score of 13 were cutoff values for hospital morbidity. CONCLUSIONS Careful consideration of operative indications and methods are necessary in cirrhotic patients with low platelet counts or high MELD scores. A high incidence of hospital morbidity is predicted in patients with platelet counts of less than 9.6 x 10(4)/microL or MELD scores exceeding 13.

Increased lung injury in pulmonary hypertensive patients during open heart operations

To investigate lung injury in adult open heart operations during extracorporeal circulation, we measured plasma chemiluminescence levels. Nineteen patients were divided into two groups depending on preoperative pulmonary artery pressure: a pulmonary hypertension group (n = 11) and a control group (n = 8). Plasma samples were taken simultaneously from arterial and central venous lines at six different points during and early after operation. Arteriovenous difference of chemiluminescence (counts/10 seconds) increased significantly only in the pulmonary hypertension group (from -19.1 +/- 8.3 at the end of cross-clamping to 23.7 +/- 12.4 at the end of bypass; p < 0.01). There was a positive correlation between peak values of arterial plasma chemiluminescence and postoperative respiratory index in the pulmonary hypertension group (p < 0.05). In addition, during the first 12 hours postoperatively, arteriovenous difference of chemiluminescence in the pulmonary hypertension group changed significantly from negative to positive values (p < 0.05). These data suggest that free radical activity (detected by chemiluminescence) was deeply involved in lung injury during and also early after open heart operations, especially in pulmonary hypertensive patients.

Repair of postinfarction ventricular septal defect with joined endocardial patches.

We describe a technique for repair of ventricular septal defect with two bovine pericardial patches joined to make a single pouch. The size of the finished pouch can be adjusted as desired after both patches are sutured to the myocardium, unlike when one patch is used. Suturing is easier than when a single patch is used.

Results of long segmental reconstruction of left anterior descending artery using left internal thoracic artery.

BACKGROUND We performed long segmental reconstruction of the left anterior descending coronary artery (LAD) using the left internal thoracic artery (LITA) in patients with diffusely diseased coronary arteries. Our study investigated short- and long-term outcomes and angiographic results after complete revascularization using this technique. METHODS Between March 1995 and March 2001, 112 patients (mean age 63 years) underwent long segmental LAD reconstruction (≥2 cm) with or without endarterectomy using the LITA. Of these, 68 patients (61%) had a history of old myocardial infarction, 44 (39%) had undergone prior percutaneous coronary intervention, 39 (35%) had unstable angina, and 11 (10%) required preoperative intraaortic balloon pumping. RESULTS The majority of patients (96%) underwent operation under cardiac arrest. All patients underwent a complete revascularization with long segmental LAD reconstruction using the LITA. The average length of arteriotomy was 3.7 cm, and 43 patients (38%) underwent extensive (≥4 cm) LAD reconstruction. Endarterectomy was performed in 37 patients (33%). The early mortality rate was 1.8% (2 of 112). Perioperative myocardial infarction in the LAD territory was 5.4%. The 5- and 10-year survival rates were 91% and 74%, respectively. Freedom from major adverse cardiac events at 10 years was 77%. Early angiography (n = 99) showed a 99% excellent patency rate of the LITA. Midterm (n = 61) and long-term (n = 23) follow-up angiography both showed 100% excellent patency rate of the LITA. CONCLUSIONS Long segmental LAD reconstruction with or without endarterectomy using the LITA provided excellent long-term outcomes and acceptable early operative results, even in patients with diffusely diseased coronary arteries.

Therapeutic Potential of Unrestricted Somatic Stem Cells Isolated from Placental Cord Blood for Cardiac Repair Post Myocardial Infarction

Objective—Unrestricted somatic stem cells (USSCs) were successfully identified from human cord blood. However, the efficacy of USSC transplantation for improving left ventricular (LV) function post myocardial infarction (MI) is still controversial. Methods and Results—PBS, 1×106 human fibroblasts (Fbr), 1×105 USSCs (LD), or 1×106 USSCs (HD) were transplanted intramyocardially 20 minutes after ligating the LAD of nude rats. Echocardiography and a microtip conductance catheter at day 28 revealed a dose-dependent improvement of LV function after USSC transplantation. Necropsy examination revealed dose-dependent augmentation of capillary density and inhibition of LV fibrosis. Dual-label immunohistochemistry for cardiac troponin-I and human nuclear antigen (HNA) demonstrated that human cardiomyocytes (CMCs) were dose-dependently generated in ischemic myocardium 28 days after USSC transplantation. Similarly, dual-label immunostaining for smooth muscle actin and class I human leukocyte antigen or that for von Willebrand factor and HNA also revealed a dose-dependent vasculogenesis after USSC transplantation. RT-PCR indicated that expression of human-specific genes of CMCs, smooth muscle cells, and endothelial cell markers in infarcted myocardium were significantly augmented in USSC-treated animals compared with control groups. Conclusions—USSC transplantation leads to functional improvement and recovery from MI and exhibits a significant and dose-dependent potential for concurrent cardiomyogenesis and vasculogenesis.

Coagulofibrinolysis during heparin-coated cardiopulmonary bypass with reduced heparinization

BACKGROUND We examined the safety of reduced systemic heparinization during heparin-coated cardiopulmonary bypass by measuring coagulofibrinolitic indices, including fibrinopeptide A, which directly reflects fibrinogenesis. METHODS Twenty-four patients who had elective cardiac operations were perfused using a circuit coated with covalently bonded heparin. Twelve patients received 300 U/kg of heparin and the remaining 12 patients received 150 U/kg. Blood was obtained for the measurement of thrombin-antithrombin III complexes, fibrinopeptide A, plasmin-alpha 2 plasmin inhibitor complexes, and D-dimer preoperatively; after heparin administration; 10, 60, and 90 minutes after the start of bypass; after protamine administration; and 1, 3, 6, 12, and 24 hours after the end of bypass. RESULTS Preoperative, intraoperative, and postoperative variables including postoperative bleeding were not significantly different between the two groups. Further, there were no complications in either group. No significant differences between the two groups were noted for any hematologic index at any time point. CONCLUSIONS Reduced systemic heparinization combined with a heparin-coated cardiopulmonary bypass circuit is biochemically and clinically safe but does not reduce postoperative bleeding.

Asymptomatic Thrombosis as a Late Complication of a Retrohepatic Vena Caval Graft Performed for Primary Leiomyosarcoma of the Inferior Vena Cava: Report of a Case

Abstract.A 63-year-old woman successfully underwent a graft replacement of the retrohepatic inferior vena cava with a ringed polytetrafluoroethylene graft for primary leiomyosarcoma of the inferior vena cava (IVC). Although anticoagulant had been administered, a thrombus was found in the IVC just cranial of the downstream anastomosis 67 months after the operation. The patient remained free of symptoms, and she had no evidence of any tumor recurrence. She underwent a complete resection with a prosthetic reconstruction for leiomyosarcoma of the IVC and has since been able to enjoy a reasonably long-term survival. The occurrence of thrombosis must be kept in mind in the long-term follow-up of such cases.

Echocardiography-guided pericardiocentesis with a needle attached to a probe

Pericardiocentesis with a needle attached to a probe was performed under two-dimensional echocardiographic guidance in 9 patients with pericardial effusion after cardiac operations. The first 5 mm of the tip of a puncture needle for percutaneous transhepatic cholangiodrainage is scratched with a scalpel to give the tip high echo intensity. When the probe is placed on the skin, the direction of puncture at that probe angle appears automatically on the monitor.

Synchrotron Radiation Coronary Microangiography for Morphometric and Physiological Evaluation of Myocardial Neovascularization Induced by Endothelial Progenitor Cell Transplantation

Background—Therapeutic effect of stem cell transplantation (SCTx) for myocardial neovascularization has been evaluated by histological capillary density in small animals. However, it has been technically difficult to obtain imaging evidence of collateral formation by conventional angiography. Methods and Results—Peripheral blood CD34+ and CD34− cells were isolated from patients with critical limb ischemia. PBS, CD34− cells, or CD34+ cells were intramyocardially transplanted after ligating LAD of nude rats. Coronary angiography of ex vivo beating hearts 5 and 28 days after the treatment was performed using the third generation synchrotron radiation microangiography (SRM), which has potential to visualize vessels as small as 20 &mgr;m in diameter. The SRM was performed pre and post sodium nitroprusside (SNP) to examine vascular physiology at each time point. Diameter of most collateral vessels was 20 to 120 &mgr;m, apparently invisible size in conventional angiography. Rentrop scores at day 28 pre and post SNP were significantly greater in CD34+ cell group than other groups (P<0.01). To quantify the extent of collateral formation, angiographic microvessel density (AMVD) in the occluded LAD area was analyzed. AMVD on day 28 post SNP, not pre SNP, was significantly augmented in CD34+ cell group than other groups (P<0.05). AMVD post SNP closely correlated with histological capillary density (R=0.82, P<0.0001). Conclusions—The SRM, capable of visualizing microvessels, may be useful for morphometric and physiological evaluation of coronary collateral formation by SCTx. The novel imaging system may be an essential tool in future preclinical/translational research of stem cell biology.