Michiharu Suga

Bone marrow mononuclear cell transplantation had beneficial effects on doxorubicin-induced cardiomyopathy

BACKGROUND Cell transplantation is a promising therapy for treating end-stage heart failure. Bone marrow mononuclear cells (BMMNC) have been used to enhance angiogenesis in ischemic heart disease. However, the effect of BMMNC transplantation in non-ischemic dilated cardiomyopathy is unknown. In this study, we evaluated the efficacy of BMMNC transplantation in doxorubicin-induced cardiomyopathy in a rat model. METHODS Doxorubicin (15 mg/kg, IP) was introduced into 52 Lewis rats. They were divided into 3 groups at 4 weeks after injection: transplant group (TX, BMMNC [1 x 10(6)] implantation, n = 18), control group (CN, saline injection, n = 18), and sham group (SH, thoracotomy, n = 16). At 4 weeks after surgery, we used echocardiography to measure systolic left ventricular diameter (LVDs), diastolic left ventricular diameter (LVDd), fractional shortening (FS), and left ventricular wall thickness/LVDs. We used a Langendorff apparatus to measure systolic, diastolic, and developed pressures. We used radioimmunoassay to measure circulating atrial natriuretic peptide concentration, and we performed histologic study, including electron-microscopic study. RESULTS Left ventricular wall thickness/LVDs in the TX group was the largest of all groups (p < 0.05). Systolic and developed pressures in the TX group were the greatest (p < 0.005). Systolic left ventricular diameter, FS, and end-diastolic pressure in the TX group were smaller than in the SH group (p < 0.05). These cardiac parameters did not differ significantly between TX and CN groups, but secondary changes (decreased heart weight, developed ascites, and increased atrial natriuretic peptide concentration) caused by doxorubicin-induced heart failure were most attenuated in the TX group. In the TX group, vascular density was greatest (p < 0.05) in the left ventricular free wall and in the septum. In addition, electron microscopy showed that myocardium in the TX group was most maintained. CONCLUSION Bone marrow mononuclear cell transplantation had beneficial effects in doxorubicin-induced cardiomyopathy.

Activated protein C attenuates cardiopulmonary bypass–induced acute lung injury through the regulation of neutrophil activation

OBJECTIVE Cardiopulmonary bypass is known to induce systemic inflammatory responses that injure multiple organs, especially the lungs. Activated protein C has been demonstrated to play an important role in the regulation of inflammation in addition to coagulation. We investigated the anti-inflammatory effects of activated protein C in a rat model of cardiopulmonary bypass. METHODS Rats were randomized to receive an intravenous bolus of vehicle (control), 0.1 mg/kg diisopropyl fluorophosphate-activated protein C, or 0.1 mg/kg activated protein C 10 minutes before the initiation of cardiopulmonary bypass. Rats underwent cardiopulmonary bypass for 60 minutes followed by another 60-minute observation. RESULTS The activated protein C group showed significantly higher mean arterial oxygen pressure and lower mean lung wet-to-dry weight ratio after cardiopulmonary bypass than the control and diisopropyl fluorophosphate-activated protein C groups. Furthermore, lung pathology revealed minimal inflammatory change in the activated protein C group. A marked increase in CD11b expression and a decrease in CD62L expression after cardiopulmonary bypass were observed in the control and diisopropyl fluorophosphate-activated protein C groups. However, administration of activated protein C significantly attenuated these changes. Lung content of tumor necrosis factor-α and interleukin-1β in the activated protein C group tended to be lower than in the other groups. Lung content of macrophage inflammatory protein-2 in the activated protein C group was significantly lower than in the diisopropyl fluorophosphate-activated protein C group. CONCLUSIONS Administration of activated protein C before cardiopulmonary bypass attenuates acute lung injury induced by cardiopulmonary bypass at least in part through the inhibition of neutrophil activation and possibly via the attenuation of proinflammatory cytokine production in this rat model of cardiopulmonary bypass.

Transplant immunosuppression enhances efficiency of adenoviral-mediated gene retransfection: inhibition of interferon-γ and immunoglobin G

BACKGROUND Transplant immunosuppression regimen facilitates successful adenovirus-mediated gene transfection and retransfection in the rat lung. Herein, we investigated the effect of this strategy on circulating cytokines and antiadenoviral immunoglobin G antibody. METHODS Male Lewis rats were transfected with 1 x 10(9) pfu/mL of E1-deleted Ad5CMVLacZ vector transtracheally. Rats were randomly assigned to receive daily intraperitoneal triple immunosuppression regimen consisting of cyclosporine (15 mg/kg per day), azathioprine (6 mg/kg per day), and methylprednisolone (2.5 mg/kg per day), or normal saline solution. Retransfection was performed 35 days later to all nonimmunosuppressed animals, whereas immunosuppressed rats were further randomized to receive retransfection or phosphate-buffered saline. Animals were sacrificed on days 1, 2, 7, 35, 42, and 49 after the initial transfection. Beta-galactosidase activity was measured on lung homogenates. Interferon-gamma, tumor necrosis factor-alpha, and antiadenoviral immunoglobin G were measured from the serum. RESULTS Enhanced and prolonged transgene expression was observed in immunosuppressed animals, especially after retransfection. Concentrations of serum tumor necrosis factor-alpha in both groups were less than 12 pg/mL throughout the study. A significant increase in serum interferon-gamma levels was observed in nonimmunosuppressed animals after retransfection; this was not seen in the immunosuppressed animals. Serum antiadenoviral immunoglobin G titers in both groups were sharply elevated on day 1, and declined to basal levels by day 7, reflecting a preexisting level of humoral immunity to adenovirus. The titer in nonimmunosuppressed rats was significantly increased after retransfection, but remained at very low level in immunosuppressed animals. CONCLUSIONS Inhibition of interferon-gamma and antiadenoviral immunoglobin G production by triple immunosuppressants may be part of the mechanisms that lead to enhanced and prolonged transgene expression after retransfection.

Suppressive effect of phosphodiesterase type 4 inhibition on systemic inflammatory responses after cardiopulmonary bypass

Cardiopulmonary bypass (CPB) induces excessive production of endogenous proinflammatory mediators such as cytokines and elastase, which are responsible for the subsequent development of systemic inflammatory response syndrome (SIRS). In this study, we investigated the protective effect of rolipram against SIRS after CPB. Rats were divided into three groups (n = 5 in each): control (C), rolipram (R), and sham (S). Rats in groups C and R underwent CPB for 60 min followed by 60 min of observation, while those in group S were observed for 120 min without CPB. In group R, 40 µg/kg/min of rolipram was intravenously administered throughout the experiment. CD11b expression on neutrophils was analyzed using flow cytometry. Serum concentrations of tissue necrosis factor α (TNF-α), interleukin 1β (IL-1β), macrophage inflammatory protein 2 (MIP-2), and elastase were also determined. CD11b expression at the end of the experiment was unchanged from the initial value in group R, whereas that in group C increased to almost double, and that in group S also showed a slight increase (P < 0.01). Serum TNF-α levels in groups R and S were lower than those observed in group C (P < 0.05). Serum IL-1β and MIP-2 levels in groups C and R tended to be higher than those in group S, although the difference was not statistically significant. Regarding elastase, group R showed a significantly lower value than group C and a higher value than group S (P < 0.05). Phosphodiesterase type 4 inhibition seems to suppress CPB-induced SIRS through the regulation of proinflammatory mediators in this rat model.