Frequent somatic mutations in epigenetic regulators in newly diagnosed chronic myeloid leukemia.

Although tyrosine kinase inhibitors (TKIs) have significantly improved the prognosis of chronic myeloid leukemia (CML), the ability of TKIs to eradicate CML remains uncertain and patients must continue TKI therapy for indefinite periods. In this study, we performed whole-exome sequencing to identify somatic mutations in 24 patients with newly diagnosed chronic phase CML who were registered in the JALSG CML212 study. We identified 191 somatic mutations other than the BCR-ABL1 fusion gene (median 8, range 1-17). Age, hemoglobin concentration and white blood cell counts were correlated with the number of mutations. Patients with mutations ⩾6 showed higher rate of achieving major molecular response than those<6 (P=0.0381). Mutations in epigenetic regulator, ASXL1, TET2, TET3, KDM1A and MSH6 were found in 25% of patients. TET2 or TET3, AKT1 and RUNX1 were mutated in one patient each. ASXL1 was mutated within exon 12 in three cases. Mutated genes were significantly enriched with cell signaling and cell division pathways. Furthermore, DNA copy number analysis showed that 2 of 24 patients had uniparental disomy of chromosome 1p or 3q, which disappeared major molecular response was achieved. These mutations may play significant roles in CML pathogenesis in addition to the strong driver mutation BCR-ABL1.

Comprehensive analysis of genetic alterations and their prognostic impacts in adult acute myeloid leukemia patients.

To clarify the cooperative roles of recurrently identified mutations and to establish a more precise risk classification system in acute myeloid leukemia (AML), we comprehensively analyzed mutations in 51 genes, as well as cytogenetics and 11 chimeric transcripts, in 197 adult patients with de novo AML who were registered in the Japan Adult Leukemia Study Group AML201 study. We identified a total of 505 mutations in 44 genes, while only five genes, FLT3, NPM1, CEBPA, DNMT3A and KIT, were mutated in more than 10% of the patients. Although several cooperative and exclusive mutation patterns were observed, the accumulated mutation number was higher in cytogenetically normal AML and lower in AML with RUNX1-RUNX1T1 and CBFB-MYH11, indicating a strong potential of these translocations for the initiation of AML. Furthermore, we evaluated the prognostic impacts of each sole mutation and the combinations of mutations and/or cytogenetics, and demonstrated that AML patients could be clearly stratified into five risk groups for overall survival by including the mutation status of DNMT3A, MLL-PTD and TP53 genes in the risk classification system of the European LeukemiaNet. These results indicate that the prognosis of AML could be stratified by the major mutation status in combination with cytogenetics.

MAPKs, activator protein-1 and nuclear factor-κB mediate production of interleukin-1ß-stimulated cytokines, prostaglandin E2 and MMP-1 in human periodontal ligament cells.

BACKGROUND AND OBJECTIVE: Determination of the interleukin-1 (IL-1) signaling cascades that lead to the production of various inflammatory mediators and catabolic factors may clarify attractive targets for therapeutic intervention for periodontitis. We comprehensively assessed the involvement of MAPKs, activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) in IL-1ß-induced production of interleukin-6 (IL-6), interleukin-8 (IL-8), prostaglandin E(2) (PGE(2) ) and MMP-1 in human periodontal ligament cells. MATERIAL AND METHODS: Human periodontal ligament cells were pretreated with an inhibitor for each of the MAPKs or NF-κB and subsequently treated with IL-1ß. Following treatment, phosphorylation of three types of MAPK (ERK, p38 MAPK and c-Jun N-terminal kinase), IκB kinase (IKK) α/ß/γ and IκB-α, as well as the DNA binding activity of AP-1 and NF-κB and the production of IL-6, IL-8, PGE(2) and MMP-1, were determined by western blotting, a gel mobility shift assay and ELISA, respectively. RESULTS: The three MAPKs, simultaneously activated by IL-1ß, mediated the subsequent DNA binding of AP-1 at various magnitudes, while IKKα/ß/γ, IκB-α and NF-κB were also involved in the IL-1 signaling cascade. Furthermore, IL-1ß stimulated the production of IL-6, IL-8, PGE(2) and MMP-1 via activation of the three MAPKs and NF-κB, because inhibitors of these significantly suppressed the IL-1ß-stimulated production of these factors. CONCLUSION: Our results strongly suggest that MAPK, AP-1 and NF-κB mediate the IL-1ß-stimulated synthesis of IL-6, IL-8, PGE(2) and MMP-1 in human periodontal ligament cells. Therefore, inhibition of activation of MAPK, AP-1 and/or NF-κB may lead to therapeutic effects on progression of periodontitis.

CMC-544 (inotuzumab ozogamicin), an anti-CD22 immuno-conjugate of calicheamicin, alters the levels of target molecules of malignant B-cells.

We studied the effect of CMC-544, the calicheamicin-conjugated anti-CD22 monoclonal antibody, used alone and in combination with rituximab, analyzing the quantitative alteration of target molecules, that is, CD20, CD22, CD55 and CD59, in Daudi and Raji cells as well as in cells obtained from patients with B-cell malignancies (BCM). Antibody inducing direct antiproliferative and apoptotic effect, complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) were tested separately. In Daudi and Raji cells, the CDC effect of rituximab significantly increased within 12 h following incubation with CMC-544. The levels of CD22 and CD55 were significantly reduced (P<0.001 in both cells) after incubation with CMC-544, but CD20 level remained constant or increased for 12 h. Similar results were obtained in cells from 12 patients with BCM. The antiproliferative and apoptotic effect of CMC-544 were greater than that of rituximab. The ADCC of rituximab was not enhanced by CMC-544. Thus, the combination of CMC-544 and rituximab increased the in vitro cytotoxic effect in BCM cells, and sequential administration for 12 h proceeded by CMC-544 was more effective. The reduction of CD55 and the preservation of CD20 after incubation with CMC-544 support the rationale for the combined use of CMC-544 and rituximab.

Efficacy of gemtuzumab ozogamicin on ATRA- and arsenic-resistant acute promyelocytic leukemia (APL) cells.

Acute promyelocytic leukemia (APL) cells express a considerable level of CD33, which is a target of gemtuzumab ozogamicin (GO), and a significantly lower level of P-glycoprotein (P-gp). In this study, we examined whether GO was effective on all-trans retinoic acid (ATRA)- or arsenic trioxide (ATO)-resistant APL cells. Cells used were an APL cell line in which P-gp was undetectable (NB4), ATRA-resistant NB4 (NB4/RA), NB4 and NB4/RA that had been transfected with MDR-1 cDNA (NB4/MDR and NB4/RA/MDR, respectively), ATO-resistant NB4 (NB4/As) and blast cells from eight patients with clinically ATRA-resistant APL including two patients with ATRA- and ATO-resistant APL. The efficacy of GO was analyzed by (3)H-thymidine incorporation, the dye exclusion test and cell cycle distribution. GO suppressed the growth of NB4, NB4/RA and NB4/As cells in a dose-dependent manner. GO increased the percentage of hypodiploid cells significantly in NB4, NB4/RA and NB4/As cells, and by a limited degree in NB4/MDR and NB4/RA/MDR cells. Similar results were obtained using blast cells from the patients with APL. GO is effective against ATRA- or ATO-resistant APL cells that do not express P-gp, and the mechanism of resistance to GO is not related to the mechanism of resistance to ATRA or ATO in APL cells. Leukemia (2005) 19, 1306-1311. doi:10.1038/sj.leu.2403807; published online 26 May 2005.

Analysis of pathological risk factors for lymph node metastasis of submucosal invasive colon cancer.

There are currently no universally accepted indications and criteria for additional surgical resection of the colorectum after endoscopic resection of the submucosal invasive cancer. The purpose of the present study is to establish accurate indications and criteria for additional surgical resection of the colorectum, based on the prediction of lymph node metastasis, after endoscopic resection of the submucosal invasive cancer. We investigated 140 submucosal invasive colorectal cancers and analyzed the pathologic factors of lymph node metastasis. The tumors were evaluated for pathologic factors in the invasive area of the submucosal carcinoma and were compared between the cases with lymph node metastasis and those without lymph node metastasis. Lymph node metastasis was observed in 13 cases (9%). Univariate logistic regression analysis showed that the depth of invasion, cribriform-type structural atypia, absence of lymphoid infiltration, lymphatic permeation, and venous permeation were statistically significant as risk factors for lymph node metastasis. Multivariate logistic regression analysis showed that the important risk factors included, in decreasing order, lymphatic permeation, absence of lymphoid infiltration, cribriform-type structural atypia, venous permeation, and depth of invasion. Submucosal invasion of 2 mm or more, and/or, depth of lymphatic permeation of 2 mm or more are risk factors for lymph node metastasis. The pathologic criteria based on our results for additional colectomy enables greater accuracy selection of patients who will undergo further surgical treatment after endoscopic resection.

Reduced effect of gemtuzumab ozogamicin (CMA-676) on P-glycoprotein and/or CD34-positive leukemia cells and its restoration by multidrug resistance modifiers.

Gemtuzumab ozogamicin (CMA-676), a calicheamicin-conjugated humanized anti-CD33 mouse monoclonal antibody, has recently been introduced clinically as a promising drug for the treatment of patients with acute myeloid leukemia (AML), more than 90% of which express CD33 antigen. However, our recent study suggested that CMA-676 was excreted by a multi- drug-resistance (MDR) mechanism in P-glycoprotein (P-gp)-expressing leukemia cell lines. We analyzed the in vitro effects of CMA-676 on leukemia cells from 27 AML patients in relation to the amount of P-gp, MDR-associated protein 1 (MRP1), CD33 and CD34, using a multi-laser-equipped flow cytometer. The cytocidal effect of CMA-676, estimated by the amount of hypodiploid portion on cell cycle, was inversely related to the amount of P-gp estimated by MRK16 monoclonal antibody (P = 0.004), and to the P-gp function assessed by intracellular rhodamine-123 accumulation in the presence of PSC833 or MS209 as a MDR modifier (P = 0.0004 and P = 0.002, respectively). In addition, these MDR modifiers reversed CMA-676 resistance in P-gp-expressing CD33(+) leukemia cells (P = 0.001 with PSC833 and P = 0.0007 with MS209). In CD33(+) AML cells from 13 patients, CMA-676 was less effective on CD33(+)CD34(+) than CD33(+)CD34(-) cells (P = 0.002). PSC833 partially restored the effect of CMA-676 in CD33(+)CD34(+) cells. These results suggest that the combined use of CMA-676 and a MDR modifier will be more effective on CD33(+) AML with P-gp-related MDR.

Arsenic trioxide therapy for relapsed or refractory Japanese patients with acute promyelocytic leukemia: need for careful electrocardiogram monitoring.

Recent studies have shown that arsenic trioxide (As(2)O(3)) can induce complete remission in patients with acute promyelocytic leukemia (APL). We tested the efficacy and safety of As(2)O(3) for the treatment of patients with APL who had relapsed from or become refractory to all-trans retinoic acid (ATRA) and conventional chemotherapy in a prospective study. As(2)O(3) at a dose of 0.15 mg/kg was administered until the date of bone marrow remission to a maximum of 60 days. In patients who achieved complete remission (CR), one additional course of As(2)O(3) was administered using the same dose for 25 days. Of 14 patients, 11 (78%) achieved CR. Six of 10 patients who achieved CR showed disappearance of PML-RARalpha transcript by RT-PCR assay. The duration of As(2)O(3)-induced CR ranged from 4 to 22 months (median, 8 months) at a median follow-up of 17 months. Adverse events included 13 electrocardiogram abnormalities (13 QTc prolongation, eight ventricular premature contraction, four nonsustained ventricular tachycardia and two paroxysmal supraventricular tachycardia), seven nausea and vomiting, four pruritus, three peripheral neuropathy, three fluid retention and one APL differentiation syndrome. Four patients received antiarrhythmic agents. Hyperleukocytosis developed in five patients and in three cytotoxic drugs were necessary. Other adverse events were relatively mild. As(2)O(3) treatment is effective and relatively safe in relapsed or refectory patients with APL. Cardiac toxicities in patients with QTc prolongation should be carefully monitored.

15-Deoxy-delta 12,14-prostaglandin J2 and thiazolidinediones activate the MEK/ERK pathway through phosphatidylinositol 3-kinase in vascular smooth muscle cells.

Peroxisome proliferator-activated receptor (PPAR) gamma belongs to the nuclear receptor superfamily of ligand-dependent transcription factors. Recent results have shown that the ligands for nuclear receptors have rapid effects so called "nongenomic" effects, which are observed within minutes after stimulation. We examined whether 15-deoxy-Delta(12,14)-prostaglandin J(2) (15-d-PGJ2) had rapid effects on cultured vascular smooth muscle cells. Phosphorylation of ERK and c-fos mRNA expression were determined by Western and Northern blot analyses, respectively. PPAR gamma agonists 15-d-PGJ2 and thiazolidinediones such as pioglitazone and troglitazone elicited rapid activation of ERK within 15 min and induced c-fos mRNA expression within 30 min, whereas the PPAR alpha agonist bezafibrate failed to activate ERK. 15-d-PGJ2-induced expression of c-fos mRNA was blocked by PD98059 or U0126, two ERK kinase inhibitors, suggesting that the MEK/ERK pathway mediates 15-d-PGJ2-induced c-fos gene expression. Furthermore, pretreatment with wortmannin, an inhibitor of phosphatidylinositol 3 (PI3)-kinase, inhibited 15-d-PGJ2-induced ERK activation and c-fos mRNA expression, suggesting that PI3-kinase is involved in the process. An electrophoretic mobility shift assay showed that 15-d-PGJ2 enhanced AP-1 binding activity to AP-1 consensus sequence in a time-dependent manner. 15-d-PGJ2 increased thymidine incorporation in a PI3-kinase-dependent manner. Taken together, our findings show that 15-d-PGJ2 and thiazolidinediones activate the MEK/ERK pathway through PI3-kinase and lead to c-fos mRNA expression and DNA synthesis. These findings indicate a novel regulatory mechanism of gene expression by 15-d-PGJ2 and thiazolidinediones.

Thrombin induces interleukin-6 expression through the cAMP response element in vascular smooth muscle cells.

The plasma level of interleukin-6 (IL-6) is elevated in patients with acute coronary syndromes and has prognostic value. Thrombin is a potent mitogen for vascular smooth muscle cells (VSMCs) and plays an important role in the progression of atherosclerosis. We examined the mechanism of thrombin-induced IL-6 expression in VSMCs. Thrombin induced IL-6 mRNA and protein expression in a dose-dependent manner. Pharmacological inhibition of extracellular signal-regulated protein kinase (ERK), p38 mitogen-activated protein kinase (MAPK), or epidermal growth factor receptor (EGF-R) suppressed the thrombin-induced IL-6 expression. Deletion and mutation analysis of the promoter region of the IL-6 gene by using luciferase as a reporter showed that the DNA segment between -228 and -150 bp containing the cAMP response element (CRE) site played a critical role. Thrombin also induced phosphorylation of CRE binding protein (CREB) in an ERK- and a p38 MAPK-dependent manner. Overexpression of the dominant-negative form of CREB inhibited thrombin-induced IL-6 mRNA expression. These results suggest that the CRE site and CREB play an important role in thrombin-induced IL-6 gene expression in VSMCs. Transactivation of EGF-R and activation of ERK and p38 MAPK are involved in this process. CREB may be a novel transcription factor that regulates thrombin-induced gene expression.

cAMP response element-binding protein mediates thrombin-induced proliferation of vascular smooth muscle cells.

Thrombin is a potent mitogen for vascular smooth muscle cells (VSMCs) and plays an important role in the progression of atherosclerosis. Although recent reports have suggested that cAMP response element-binding protein (CREB) is necessary for the survival of neuronal cells, the role of CREB in VSMC proliferation is not determined. We examined the role of CREB in thrombin-induced VSMC proliferation and the effect of thrombin on phosphorylation of CREB at Ser133, which is a critical marker for activation by Western blot analysis. Thrombin induced phosphorylation of CREB in a dose-dependent manner. An oligopeptide, SFLLRN, which activates the thrombin receptor, also induced the phosphorylation of CREB. Inhibition of extracellular signal-regulated protein kinase or inhibition of p38 mitogen-activated protein kinase suppressed the thrombin-induced CREB phosphorylation. Inhibition of the epidermal growth factor receptor by AG1478 also inhibited the thrombin-induced CREB phosphorylation. Overexpression of the dominant-negative form of CREB inhibited thrombin-induced c-fos mRNA expression and incorporation of [(3)H]thymidine and [(3)H]leucine. These results suggest that CREB-dependent gene transcription plays a critical role in thrombin-induced proliferation and hypertrophy of VSMCs. Transactivation of the epidermal growth factor receptor and 2 mitogen-activated protein kinase pathways are involved in this process. CREB may be a novel transcription factor mediating the vascular remodeling process induced by thrombin.

Increased inactivation of nitric oxide is involved in impaired coronary flow reserve in heart failure.

Recent evidence suggests that increased inactivation of endothelium-derived nitric oxide (NO) by oxygen free radical (OFR) formation is involved in the pathogenesis of endothelial dysfunction in heart failure (HF). However, it is unclear whether increased OFR limits coronary flow reserve in HF. To test this hypothesis, we examined the effects of antioxidant therapy on coronary flow reserve in a canine model of tachycardia-induced HF. The flow reserve (percent increase in coronary blood flow) to adenosine or to 20-s ischemia was less and OFR formation (electron-spin resonance spectroscopy) in myocardial tissues was greater in HF dogs than in controls. Immunohistochemical staining of 4-hydroxy-2-nonenal, an OFR-induced lipid peroxide, was detected in coronary microvessels of HF dogs. Intracoronary infusion of a cell-permeable OFR scavenger, tiron, suppressed OFR formation and improved the vasodilating capacity to adenosine or brief ischemia in HF dogs but not in controls. A NO synthesis inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), diminished the beneficial effects of tiron in HF dogs. Vasodilation to sodium nitroprusside was similar between control and HF dogs, and no change in its response was noted with tiron or tiron + L-NMMA in either group. In summary, antioxidant treatment with tiron improved coronary flow reserve by increasing NO bioactivity in HF dogs. Thus increased OFR formation may impair coronary flow reserve in HF by reducing NO bioactivity.

All-trans retinoic acid (ATRA) differentiates acute promyelocytic leukemia cells independently of P-glycoprotein (P-gp) related multidrug resistance.

Here the relationship between all-trans retinoic acid (ATRA)-resistance and P-glycoprotein (P-gp)-associated multidrug resistance (MDR) is discussed in acute promyelocytic leukemia (APL). First, the remission rates of ATRA therapy are similar in relapsed/refractory APL to the preceding chemotherapy given and in newly diagnosed APL. Second, MDR1 cDNA-transduced NB4 (NB4/MDR) cells accumulate less Rhodamine-123 (Rh123) than NB4 cells, but there is no difference in the intracellular ATRA concentration between them. PSC833 or MS209. MDR modifiers, increases the intracellular accumulation of Rh123 in NB4/MDR and APL cells expressing P-gp, but not of ATRA. Third, the expression of CD11b, the NBT reduction activity, the proportion of apoptotic cells and the morphology are not different between NB4/MDR and NB4 cells, and between APL cells expressing P-gp and not. APL cells express little P-gp, and mainly express CD33 but no CD34. Despite previous reports that ATRA-resistant APL cells express more P-gp than ATRA-sensitive ones, P-gp and ATRA-resistance seems to exist independently.

Elevated interleukin-1beta in pericardial fluid of patients with ischemic heart disease.

BACKGROUND: Inflammatory cytokines may play an important role in the pathogenesis of atherosclerosis and heart failure. We have previously demonstrated that long-term treatment with interleukin (IL)-1beta in the coronary artery and myocardium promotes coronary arteriosclerosis and impairs cardiac function, respectively. The cytokines in pericardial fluid may reflect the extent of coronary atherosclerosis and may also directly promote the atherosclerotic process. This study was designed to examine the significance of cytokine concentrations in pericardial fluid of patients with cardiovascular disease. METHODS: We measured concentrations of 10 major cytokines in the pericardial fluid of 56 consecutive patients obtained during open heart surgery, 27 with ischemic heart disease (IHD group), 21 with valvular heart disease (VHD group) and eight with congenital heart disease (CHD group). RESULTS: The pericardial concentrations of IL-1beta (pg/ml) were significantly higher in the IHD group (60 +/- 15) than in the VHD (29 +/- 5) or the CHD group (26 +/- 4) (P < 0.05 both). There was no significant difference in pericardial concentrations of other cytokines among the three groups. In the IHD group, the IL-1beta concentrations were significantly elevated in patients who had undergone emergency operations or in those with unstable angina. CONCLUSIONS: These results suggest that pericardial concentrations of IL-1beta may reflect the extent of ischemic heart disease and that elevated IL-1beta concentrations in pericardial fluid may also directly promote the process of coronary atherosclerosis.

Bisphenol-A, an environmental estrogen, activates the human orphan nuclear receptor, steroid and xenobiotic receptor-mediated transcription.

BACKGROUND: There is increasing concern about endocrine-disrupting chemicals (EDCs) which may produce adverse health effects in humans and other species. One such chemical, bisphenol-A (BPA), a monomer of polycarbonate plastics, is widely used in consumer products; it has been reported to contain estrogenic activity through binding to estrogen receptors. Cytochrome P450 mono-oxygenase 3A4 (CYP3A4) is one of the key enzymes for the metabolism of endogenous steroids and foreign chemicals in liver. The orphan nuclear receptor, steroid and xenobiotic receptor (SXR/PXR), has recently been isolated. A variety of known inducers of CYP3A4 bind to SXR/PXR, and stimulate transcription on xenobiotic-response elements (XREs) located in the promoter region of the CYP3A4 gene. Recent study has shown that EDCs, diethylhexylphthalate (DEHP) and nonylphenol, but not BPA, induce mouse SXR/PXR-mediated transcription. However, it is known that species differences in SXR alter CYP3A inducibility. OBJECTIVE: To test whether BPA stimulates human SXR/PXR-mediated transcription using reporter gene assays. METHODS: Transfection assays were performed with human SXR/PXR expression plasmid and a reporter plasmid containing the XREs in the CYP3A4 gene promoter in HepG2 cells. BPA-induced interaction of human SXR/PXR with steroid receptor coactivator-1 (SRC-1) was analyzed by mammalian two-hybrid assays. RESULTS: BPA, as well as DEHP, activated human SXR-mediated transcription on the XREs. In mammalian two-hybrid assays, BPA recruited SRC-1 to the ligand-binding domain of human SXR/PXR. CONCLUSIONS: Our observations have indicated that BPA may be a human-specific inducer of the CYP3A4 gene, and may influence the metabolism of endogenous steroids, drugs, and other xenobiotics.

Overexpression of eNOS in the RVLM causes hypotension and bradycardia via GABA release.

In this study, we examine the role of NO located in the rostral ventrolateral medulla (RVLM) in the control of blood pressure and the activity of the sympathetic nervous system. To determine the effect of an increase in NO production in the RVLM on blood pressure in conscious rats, adenovirus vectors encoding either endothelial NO synthase (AdeNOS) or beta-galactosidase (Adbetagal) were transfected into the bilateral RVLM. The local expression of endothelial NO synthase (eNOS) protein in the RVLM was confirmed by immunohistochemical staining for the eNOS protein and by Western blot analysis. Mean arterial blood pressure (MAP) and heart rate, which were monitored using a radio-telemetry system, were significantly decreased in the AdeNOS-treated group from day 5 to day 10 after the gene transfer. Urinary norepinephrine excretion was decreased on day 7 after the gene transfer in the AdeNOS-treated group. Microinjection of either N(G)-monomethyl-L-arginine (L-NMMA) or bicuculine, a gamma-amino butyric acid (GABA) receptor antagonist, into the RVLM at day 7 after the gene transfer increased MAP to significantly greater levels in the AdeNOS-treated group. However, microinjection of kynurenic acid into the RVLM on day 7 after the gene transfer did not alter MAP levels in either group. GABA and glutamate levels in the RVLM, when measured by in vivo microdialysis, were significantly increased in the AdeNOS-treated group. These results suggest that the increase in NO production caused by the overexpression of eNOS in the bilateral RVLM decreases blood pressure, heart rate, and sympathetic nerve activity in conscious rats. Furthermore, these responses may be mediated by an increased release of GABA in the RVLM.

Antiinflammatory and antiarteriosclerotic actions of HMG-CoA reductase inhibitors in a rat model of chronic inhibition of nitric oxide synthesis.

Recent studies suggest that some of the beneficial effects of 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may be due to their cholesterol-lowering independent effects on the blood vessels. Chronic inhibition of endothelial nitric oxide (NO) synthesis by oral administration of N(omega)-nitro-L-arginine methyl ester (L-NAME) to rats induces early vascular inflammation as well as subsequent arteriosclerosis. The aim of the study is to test whether treatment with statins attenuates such arteriosclerotic changes through their cholesterol-lowering independent effects. We investigated the effect of statins (pravastatin and cerivastatin) on the arteriosclerotic changes in the rat model. We found that treatment with statins did not affect serum lipid levels but markedly inhibited the L-NAME-induced vascular inflammation and arteriosclerosis. Treatment with statins augmented endothelial NO synthase activity in L-NAME-treated rats. We also found the L-NAME induced increase in Rho membrane translocation in hearts and its prevention by statins. Such vasculoprotective effects of statins were suppressed by the higher dose of L-NAME. In summary, in this study, we found that statins such as pravastatin and cerivastatin inhibited vascular inflammation and arteriosclerosis through their lipid-lowering independent actions in this model. Such antiarteriosclerotic effects may involve the increase in endothelial NO synthase activity and the inhibition of Rho activity.