Candesartan cilexetil in the management of blood pressure for acute and recurrent stroke in Japan: the Challenge-Stroke study

The Challenge-Stroke study was conducted in Japanese patients initiated on candesartan cilexetil therapy within 3 months of suffering a stroke to investigate the clinical use of candesartan and its efficacy/safety in this therapeutic setting. A total of 869 patients formed the safety analysis set. In total, 79.6% of patients with brain hemorrhage (BH) and 60.2% with brain infarction (BI) began candesartan before post-stroke day 3 and 7, respectively. Baseline average blood pressure (BP) was 152.0/83.2 mmHg in the BH group and 165.2/89.8 mmHg in the BI group; this was reduced to 125.8/75.4 mmHg and 136.3/78.1 mmHg, respectively, at 1 year. The incidence of adverse drug reactions was 6.7 and 8.0%, respectively. There were 12 recurrent strokes in the BH group and 11 in the BI group after 1 year. The risk of recurrent stroke was significantly higher for BH patients with a final systolic BP ≥150 mmHg than for those with a final systolic BP <130 mmHg (hazard ratio: 6.807; p = 0.004). Aggressive antihypertensive therapy is currently employed in Japanese patients with acute stroke. Candesartan was safe and effective for BP control in acute stroke patients. Strict BP management may be useful for secondary prevention of stroke after BH.     

Booster effect of interleukin-2 on natural killer 1.1+ cells stimulated by administration of macrophage colony-stimulating factor in mice

The authors studied the combined effects of macrophage colony-stimulating factor (M-CSF) and interleukin (IL)-2 on the functions and antitumor activity of natural killer (NK) 1.1+ cells in vitro and in vivo. NK1.1+ cells were isolated from the spleen of mice treated with saline or M-CSF, and their functions (proliferation, production of IFN-gamma, and cytotoxicity) evaluated in vitro. Although the proliferation of and production by NK1.1+ cells was stimulated by the addition of IL-2, the cells from the M-CSF-treated mice responded better. Furthermore, the cytotoxicity against Yac-1 cells and B16 melanoma cells was stimulated by M-CSF administration and enhanced by the addition of IL-2 and IL-12. These results demonstrated that M-CSF treatment augmented the functions of NK1.1 cells, and IL-2 and IL-12 boosted these activities in vitro. The authors then examined the effects of co-administration of M-CSF and IL-2 in vivo. The clearance of B16 cells in lung was augmented by the administration of M-CSF but not IL-2. However, M-CSF + IL-2 treatment further enhanced the clearance activity. The anti-metastatic activity was also enhanced by the M-CSF + IL-2 treatment. Furthermore, the survival of B16-bearing mice was prolonged by M-CSF + IL-2. These results suggested that administration of IL-2 boosts the functions of NK1.1+ cells, which are augmented preliminarily by the administration of M-CSF.     

Expression of pIX gene induced by transgene promoter: possible cause of host immune response in first-generation adenoviral vectors

First-generation (FG) adenoviral vectors (AdVs) have been widely used not only for gene therapy but also for basic studies. Because vectors of this type lack the E1A gene that is essential for the expression of other viral genes, their expression levels in target cells have been considered low. However, we found that the viral pIX gene, located immediately downstream of the inserted expression unit of the transgene, was significantly coexpressed with the transgene in cells infected with FG AdV. Whereas CAG and SRalpha promoters activated the pIX promoter considerably through their enhancer effects, the EF1alpha promoter hardly did. Moreover, when the expression unit was inserted in the rightward orientation, not only the pIX protein but also a fusion protein consisting of the N-terminal part of transgene product and pIX were sometimes coexpressed with the transgene product through an aberrant splicing mechanism. In in vivo experiments, a LacZ-expressing AdV bearing the CAG promoter caused an elevation of alanine aminotransferase, but an AdV bearing the EF1alpha promoter produced no detectable levels. Whereas the FG AdV expressing human growth hormone under the control of the CAG promoter maintained a high hormone level for less than 1 month, the FG AdV under the control of the EF1alpha promoter maintained a high level for at least 6 months. These results suggest that pIX coexpression may be one of the main causes of AdV-induced immune responses, and that the EF1alpha promoter is probably valuable for the long-term expression of FG AdV. Thus, the in vivo utility of FG AdV should be reevaluated.     

An optimal therapeutic expression level is crucial for suicide gene therapy for hepatic metastatic cancer in mice

The most serious problem in current gene therapy is discrepancies between experimental data and actual clinical outcomes, which may be due to insufficient analyses and/or inappropriate animal models. We have explored suicide gene therapy by using various clinically relevant animal models and doubt the clinical use of maximal suicide gene expression, which has been generally recommended. To explore this subject further, we studied what expression level of suicide gene and what promoter led to the maximal clinical benefit in the case of hepatic metastatic cancer in mice. Therapeutic and adverse side effects of 4 adenoviral vectors that express herpes simplex virus thymidine kinase (HSV-tk) under different promoters were scrupulously investigated in 2 mouse models of hepatic metastasis of gastric cancer that possess clinical characteristics. Surprisingly, increases in HSV-tk expression beyond a certain point, achieved by the Rous sarcoma virus long terminal repeat promoter, not only enhanced the adverse side effects of lethal hepatotoxicity and ganciclovir-independent cytotoxicity but also failed to further increase therapeutic potential. Moreover, the carcinoembryonic antigen (CEA) tumor-specific promoter, the therapeutic potential of which had been underestimated, was much more useful-even in the case of low CEA-producing cancer-than had been previously reported. In conclusion, the optimal therapeutic expression level of a suicide gene is a novel concept and a crucial factor for successful cancer gene therapy. The present results, which contradict those of previous studies, alert researchers about possible problems with ongoing and future clinical trials that lack this concept.     

Characteristics and Prognosis of Stroke in Living Donor Renal Transplant Recipients

Aims: We aimed to determine the characteristics and vascular outcomes of stroke in renal transplant (RT) recipients and compare them with those in patients on hemodialysis (HD) and those with no renal replacement therapy (RRT). Methods: In this prospective observational study, 717 patients (mean age, 70.8 years; male, 60.5%) with acute ischemic stroke within one week of onset were consecutively enrolled and followed for one year. The patients were classified into three groups: (1) living donor RT recipients (n=27); (2) patients on maintenance HD before the index stroke (n=39); and (3) those with no history of RRT (n=651). The primary outcome was a composite of major adverse cardiovascular events (MACE). Results: Diabetic nephropathy was the most common reason for RRT in both RT and HD patients. RT patients were more likely to have embolic stroke of undetermined source (33.3%) than others, whereas HD patients more often had cardioembolism (51.3%). No difference was observed in the MACE risk between the patients in RT and non-RRT groups (annual rate, 11.3% vs. 13.1%; log-rankP=0.82; hazard ratio [95% confidence interval], 0.92 [0.29-2.98]). In contrast, HD patients had a greater risk of MACE than those with no RRT (annual rate, 28.2% vs. 13.1%; log-rankP=0.019; hazard ratio [95% confidence interval], 2.24 [1.16-4.3]). Conclusions: The underlying etiologies of stroke differed in RT and HD patients. The one-year risk of MACE for stroke patients who had received an RT was lower than that for patients undergoing HD and comparable with that of patients with no RRT.