Mucinous tubular and spindle cell carcinoma with a high nuclear grade and micropapillary pattern: A case report

Mucinous tubular and spindle cell carcinoma (MTSCC) is rare in renal cell carcinoma (RCC) and usually demonstrates a low nuclear grade and a better prognosis compared with other RCCs. The authors present a case report of MTSCC containing an area of Fuhrman nuclear grade 3, in addition to an area with a micropapillary pattern. An 82-year-old man consulted a hospital due to macrohematuria, and a tumor in the right kidney was detected. The tumor was resected and histologically examined. The tumor consisted of various growth patterns: Elongated tubular structure, a papillary structure containing a micropapillary pattern and solid pattern with spindle cells. The tumor cells demonstrated Fuhrman nuclear grades 2 and 3. Invasion into the lymph vessel and metastasis into the regional lymph node were observed. Thus, the tumor was diagnosed as a high grade MTSCC. Five months following resection, a computed tomography scan suggested metastasis of the tumor into the para-aortic lymph nodes and liver, and the patient succumbed to brain metastasis. When MTSCC of kidney is observed, careful histological observation is important to avoid missing a high nuclear grade area.

A case of CD10-negative angioimmunoblastic T cell lymphoma with leukemic change and increased plasma cells mimicking plasma cell leukemia: A case report

Angioimmunoblastic T cell lymphoma (AITL) is a peripheral T cell lymphoma, known to express CD3 and CD4, and, frequently, also CD10 and c-Maf-1. Hypergammaglobulinemia is not particularly rare in patients with AITL. However, AITL in conjunction with plasmacytosis in the peripheral blood is rare. The current report presents a case of CD10-negative AITL demonstrating leukemic change and plasmacytosis in the peripheral blood mimicking plasma cell leukemia. A 78-year-old male was admitted to hospital due to systemic lymph node enlargement, high serum IgG and IgA, and increased counts of plasmacytoid cells and lymphoid cells with atypical nuclei in the peripheral blood. Initially, plasma cell leukemia was suspected, due to the extreme increase in the number of plasma cells in the peripheral blood. However, the plasma cells did not show clonal expansion on examination by flow cytometry. Based on histological analyses, following a biopsy of an enlarged lymph node, the patient was diagnosed with AITL. This case suggests that when hypergammaglobulinemia and increases in B-lineage cells are observed, AITL should be considered in addition to disorders of B-lineage cells.

Activation of phosphatidylinositol 3-kinase β by the platelet collagen receptors integrin α2β1 and GPVI: The role of Pyk2 and c-Cbl

Phosphatidylinositol 3-kinaseβ (PI3Kβ) plays a predominant role in integrin outside-in signaling and in platelet activation by GPVI engagement. We have shown that the tyrosine kinase Pyk2 mediates PI3Kβ activation downstream of integrin αIIbβ3, and promotes the phosphorylation of the PI3K-associated adaptor protein c-Cbl. In this study, we compared the functional correlation between Pyk2 and PI3Kβ upon recruitment of the two main platelet collagen receptors, integrin α2β1 and GPVI. PI3Kβ-mediated phosphorylation of Akt was inhibited in Pyk2-deficient platelets adherent to monomeric collagen through integrin α2β1, but occurred normally upon GPVI ligation. Integrin α2β1 engagement led to Pyk2-independent association of c-Cbl with PI3K. However, c-Cbl was not phosphorylated in adherent platelets, and phosphorylation of Akt occurred normally in c-Cbl-deficient platelets, indicating that the c-Cbl is dispensable for Pyk2-mediated PI3Kβ activation. Stimulation of platelets with CRP, a selective GPVI ligand, induced c-Cbl phosphorylation in the absence of Pyk2, but failed to promote its association with PI3K. Pyk2 activation was completely abrogated in PI3KβKD, but not in PI3KγKD platelets, and was strongly inhibited by Src kinases and phospholipase C inhibitors, and by BAPTA-AM. The absence of PI3Kβ activity also hampered GPVI-induced tyrosine-phosphorylation and activation of PLCγ2, preventing intracellular Ca2+ increase and phosphorylation of pleckstrin. Moreover, GPVI-induced intracellular Ca2+ increase and pleckstrin phosphorylation were also strongly inhibited in human platelets treated with the PI3Kβ inhibitor TGX-221. These results outline important differences in the regulation of PI3Kβ by GPVI and integrin α2β1 and suggest that inhibition of Pyk2 may target PI3Kβ activation in a selective context of platelet stimulation.

An autopsy case of pulmonary fissure induced by zygomycosis

For immunodeficient patients, fungi are life-threatening pathogens. In this paper, we present an autopsy case of combined zygomycosis and aspergillosis. A female in her 70s on chronic hemodialysis was admitted to a hospital suffering bloody sputum, dyspnea, and fever, probably due to perinuclear anti-neutrophil cytoplasmic antibody-related vasculitis. Antibiotics were administered and immunosuppressive therapy was started, resulting in an improvement in her condition. Pneumonia later developed, followed by pulmonary bleeding and intractable pneumothorax from which she ultimately died. On autopsy, the upper lobe of the left lung was found to have hemorrhagic necrosis and showed a large longitudinal fissure. Microscopically, Zygomycota were observed in both the lungs and heart, while Aspergillus was found in the middle lobe of the right lung. Zygomycosis, which usually has a poor prognosis, is assumed to have induced hemorrhagic infarction of the lungs, inducing pulmonary bleeding and necrosis, despite the use of lipid formulations of amphotericin B, which are effective medicines against Zygomycota.

Distinct role of Pyk2 in mediating thromboxane generation downstream of both G12/13 and integrin αIIbβ3 in platelets

Proline-rich tyrosine kinase 2 (Pyk2) is activated by various agonists in platelets. We evaluated the signaling mechanism and the functional role of Pyk2 in platelets by using pharmacological inhibitors and Pyk2-deficient platelets. We found that platelet aggregation and secretion in response to 2-methylthio-ADP (2-MeSADP) and AYPGKF were diminished in the presence of Pyk2 inhibitors or in Pyk2-deficient platelets, suggesting that Pyk2 plays a positive regulatory role in platelet functional responses. It has been shown that ADP-, but not thrombin-induced thromboxane (TxA2) generation depends on integrin signaling. Unlike ADP, thrombin activates G12/13 pathways, and G12/13 pathways can substitute for integrin signaling for TxA2 generation. We found that Pyk2 was activated downstream of both G12/13 and integrin-mediated pathways, and both 2-MeSADP- and AYPGKF-induced TxA2 generation was significantly diminished in Pyk2-deficient platelets. In addition, TxA2 generation induced by co-stimulation of Gi and Gz pathways, which is dependent on integrin signaling, was inhibited by blocking Pyk2. Furthermore, inhibition of 2-MeSADP-induced TxA2 generation by fibrinogen receptor antagonist was not rescued by co-stimulation of G12/13 pathways in the presence of Pyk2 inhibitor. We conclude that Pyk2 is a common signaling effector downstream of both G12/13 and integrin αIIbβ3 signaling, which contributes to thromboxane generation.

A novel nuclear factor κB inhibitor, dehydroxymethylepoxyquinomicin, ameliorates puromycin aminonucleoside-induced nephrosis in mice

BACKGROUND/AIMS

Minimal-change nephrotic syndrome (MCNS) is a kidney disease defined by selective proteinuria and hypoalbuminemia occurring in the absence of cellular glomerular infiltrates or immunoglobulin deposits. Recent observations suggest that nuclear factor κB (NF-κB) of podocyte is strongly associated with the development of proteinuria in MCNS. Dehydroxymethylepoxyquinomicin (DHMEQ) is a novel NF-κB inhibitor that potently inhibits DNA-binding activity of NF-κB, resulting in several therapeutic effects in various pathological conditions. We conducted this study to ask whether DHMEQ may ameliorate the nephrosis in mice induced by puromycin aminonucleoside (PAN), which is considered to be an animal model for MCNS.

METHODS/RESULTS

Pretreatment with DHMEQ alleviated the proteinuria and reversed the serum abnormalities in mice nephrosis induced by 450 mg/kg of PAN. Increased serum interleukin-6 level in PAN-induced nephrosis was also completely suppressed by DHMEQ. Electron microscopic analyses of glo-meruli indicated that DHMEQ can inhibit the podocyte foot process effacement via blocking the translocation of podocyte NF-κB from cytoplasm to nucleus.

CONCLUSIONS

These results suggest that DHMEQ can be a potential therapeutic agent for MCNS.

Switching to an L/N-type calcium channel blocker shows renoprotective effects in patients with chronic kidney disease: the Kyoto Cilnidipine Study

OBJECTIVE

This open-label, randomized controlled trial investigated the effects of cilnidipine, an L/N-type calcium channel blocker (CCB), in patients with chronic kidney disease (CKD).

METHODS

Sixty patients with CKD and well-controlled hypertension being treated with a renin- angiotensin system (RAS) inhibitor and an L-type CCB (L-CCB) were randomly assigned either to switch from the L-CCB to cilnidipine after a 4-week observation period or to continue with L-CCB treatment. Blood pressure, heart rate and renal function were monitored for 12 months. Data were available for analysis from 50 patients: 24 from the cilnidipine group and 26 from the L-CCB group.

RESULTS

Blood pressure was well controlled in both groups. After 12 months, proteinuria and heart rate were significantly decreased in the cilnidipine group, but proteinuria increased and heart rate remained unchanged in the L-CCB group. There was a significant positive correlation between the percentage changes in proteinuria and heart rate.

CONCLUSIONS

Cilnidipine has antihypertensive effects equivalent to those of L-CCBs. In patients with CKD, proteinuria can be decreased by switching from an L-CCB to cilnidipine, thereby improving renal function.

The proline-rich tyrosine kinase Pyk2 regulates platelet integrin αIIbβ3 outside-in signaling

BACKGROUND

The proline-rich tyrosine kinase Pyk2 is a focal adhesion kinase expressed in blood platelets, and is activated downstream of G-protein coupled receptors as well as integrin α2β1.

OBJECTIVE

In this study we have investigated the involvement of Pyk2 in integrin αIIbβ3 outside-in signaling in human and murine platelets.

METHODS

We analyzed the stimulation of intracellular signaling pathways in platelets from Pyk2 knockout mice adherent to immobilized fibrinogen.

RESULTS

Pyk2 was rapidly phosphorylated and activated in human and murine platelets adherent to fibrinogen through integrin αIIbβ3. Activation of Pyk2 was Src-dependent, but did not require phospholipase Cγ2 activity. Platelets from Pyk2 knockout mice showed a defective ability to adhere and spread on fibrinogen, in association with a dramatic reduction of phosphatidylinositol 3-kinase (PI3K) activation and Akt phosphorylation. Pharmacological and genetic analysis demonstrated that integrin αIIbβ3 engagement selectively stimulated the β-isoform of PI3K (PI3Kβ), and that, as for Pyk2, PI3Kβ activation required Src family kinases activity, but not phospholipase Cγ2. In fibrinogen-adherent platelets, both Pyk2 and PI3Kβ were necessary for stimulation of the small GTPase Rap1b, a regulator of cell adhesion and spreading. Integrin αIIbβ3 engagement triggered the association of the PI3Kβ regulatory subunit p85 with the adaptor protein c-Cbl, which was mediated by the p85 SH3 domain, and was independent of c-Cbl tyrosine phosphorylation. However, p85-associated c-Cbl was tyrosine phosphorylated by activated Pyk2 in fibrinogen adherent platelets.

CONCLUSIONS

These results identify a novel pathway of integrin αIIbβ3 outside-in signaling and recognize the tyrosine kinase Pyk2 as a major regulator of platelet adhesion and spreading on fibrinogen.

Macrophages play a unique role in the plaque calcification by enhancing the osteogenic signals exerted by vascular smooth muscle cells

Vascular calcification is a major risk factor for the cardiovascular disease, yet its underlying molecular mechanisms remain to be elucidated. Recently, we identified that osteogenic signals via bone morphogenetic protein (BMP)-2 exerted by vascular smooth muscle cells (VSMCs) play a crucial role in the formation of atherosclerotic plaque calcification. Here we report a synergistic interaction between macrophages and VSMCs with respect to plaque calcification. Treatment with conditioned medium (CM) of macrophages dramatically enhanced BMP-2 expression in VSMCs, while it substantially reduced the expression of matrix Gla-protein (MGP) that inhibits the BMP-2 osteogenic signaling. As a result, macrophages significantly accelerated the osteoblastic differentiation of C2C12 cells induced by VSMC-CM. In contrast, macrophage-CM did not enhance the osteoblastic gene expressions in VSMCs, indicating that macrophages unlikely induced the osteoblastic trans-differentiation of VSMCs. We then examined the effect of recombinant TNF-α and IL-1β on the VSMC-derived osteogenic signals. Similar to the macrophage-CM, both cytokines enhanced BMP-2 expression and reduced MGP expression in VSMCs. Nevertheless, only the neutralization of TNF-α but not IL-1β attenuated the effect of macrophage-CM on the expression of these genes in VSMCs, due to the very low concentration of IL-1β in the macrophage-CM. On the other hand, VSMCs significantly enhanced IL-1β expression in macrophages, which might in turn accelerate the VSMC-mediated osteogenic signals. Together, we identified a unique role of macrophages in the formation of plaque calcification in coordination with VSMCs. This interaction between macrophages and VSMCs is a potential therapeutic target to treat and prevent the atherosclerotic plaque calcification.

Neuroprotective effects of granulocyte colony-stimulating factor on ischemia-reperfusion injury of the retina

PURPOSE

It has been reported that granulocyte colony-stimulating factor (G-CSF) provides neuroprotection in models in which neuronal cell death is induced. This research was designed to investigate the effects of G-CSF on neurodegeneration of the inner retinal layer in a rat model of ischemic reperfusion (I/R) injury.

MATERIALS AND METHODS

Retinal ischemia was induced by increasing the intraocular pressure to 110 mm Hg for 45 min in the left eyes of the rats. A sham operation was carried out on the right eyes. G-CSF (100 µg/kg/day in 0.3 ml saline) or the same volume of saline was intraperitoneally injected just before the operation and continued for 4 consecutive days (a total of 5 consecutive days). Morphological examinations, including the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, were performed 7 days after I/R induction. The expression of phosphorylated AKT in the retina was examined by Western blot analysis and immunohistochemistry.

RESULTS

Cell loss in the ganglion cell layer was more significantly reduced in the I/R-induced eyes of the G-CSF-injected rats than in the I/R-induced eyes of the saline-injected rats (20.3 vs. 6.6%). The inner retinal thickness ratios, such as the inner plexiform layer to the inner limiting membrane/outer nuclear layer and the inner nuclear layer/outer nuclear layer, were significantly better preserved in the I/R-induced eyes of the G-CSF-injected rats than in the I/R-induced eyes of the saline-injected rats. TUNEL assays showed fewer apoptotic cells in the retinal sections of the I/R-induced eyes of the G-CSF-injected rats. The phosphorylation of AKT (p-AKT/AKT) was upregulated in the retinas of the I/R-induced eyes of the G-CSF-injected rats.

CONCLUSION

Our results demonstrated that systemic injection of G-CSF can protect retinal ganglion cells and inner retinal layers from I/R injury. The effects could be associated with the activation of AKT.

Abstract 339: Impaired Periaortic Adipocyte Differentiation in Angiotensin AT1 Receptor-Deficient Mice: Possible Role in Proinflammatory Phenotypic Modulation of Perivascular Adipose Tissue

[BACKGROUND] The angiotensin II type 1 (AT1) receptor in visceral white adipose tissue (WAT) is closely implicated in lipid metabolism and energy homeostasis. Recently, perivascular adipose tissue (PVAT) has been shown to play a crucial role in the development of atherosclerosis; however, the effects of AT1 on PVAT properties and their functional relevance in atherogenesis remain undefined.

[METHOD AND RESULT] We examined the fat depot-specific difference of adipose tissue among epididymal WAT, PVAT surrounding thoracic aorta, and interscapular brown adipose tissue (BAT) in 8-week-old apoE deficient (apoE-/-) mice. The expression levels of brown adipocyte marker genes (UCP-1, PGC-1α, Elovl3, PPARα, and Cidea) were significantly higher in BAT and PVAT compared with WAT (P<0.01). White adipocyte marker genes (Igfbp3, DPT, Tcf21, and Hoxc9), which were hardly expressed in BAT, showed a moderate expression levels in PVAT, suggesting that PVAT has a strikingly different phenotype from the classical WAT and BAT. We next examined the properties of PVAT in 8-week-old apoE-/-/AT1 receptor deficient (Agtr1-/-) mice. After 4 weeks of western diet, the expression levels of adipocyte differentiation maker genes (PPARγ, FABP4, c/EBPα) were markedly increased in apoE -/- PVAT (P<0.05), which was completely diminished in apoE-/-/Agtr1 -/- PVAT (P<0.01). To investigate the effect of AT1 on the periaortic adipocyte differentiation, we performed primary culture of preadipocyte from stromal vascular fraction in Agtr1 -/- and Agtr1+/+ PVAT. The mRNA expressions of adipocyte differentiation marker genes (PPARγ, FABP4, and c/EBPα) were time-dependently increased in Agtr1+/+ adipocyte. In contrast, FABP4 and c/EBPα mRNA expressions were markedly inhibited in Agtr1 -/- adipocyte, whereas PPARγ did not differ between the two groups during differentiation, suggesting that AT1 is essentially implicated in the terminal differentiation of periaortic adipocyte.

[CONCLUSION] Our findings demonstrate that AT1 regulates the expression levels of late stage of adipocyte-differentiation marker genes in PVAT, suggesting that AT1-mediated modulation of periaortic adipocyte differentiation could be a novel therapeutic target for the prevention of atherosclerosis.

Abstract 340: Phenotypic Conversion of Perivascular Adipose Tissue in Uninephrectomized Apoe-Deficient Mice: Possible Role in the Early Stage of Atherosclerosis in Chronic Kidney Disease

BACKGROUND: Chronic kidney disease (CKD) is now recognized to be an independent risk factor for cardiovascular disease. Recently, perivascular adipose tissue (PVAT) has been shown to play a crucial role in the pathogenesis of atherosclerosis; however, the role of PVAT in the CKD-associated proatherogenic actions remains undefined.

METHOD AND RESULT: Eight-week-old apoE deficient mice underwent uninephrectomy (UNX) or sham operation and were fed a western diet starting at 12 wks of age. UNX mice at the age of 20 wks showed a significant exaggeration of atherosclerotic lesion area (53%, P<0.05). Hemodynamic data, lipid profile, and plasma creatinine concentrations did not differ between the two groups. To elucidate the underlying mechanisms of minor renal insufficiency-induced atherosclerosis, we first examined the number of circulating inflammatory monocytes and the mRNA expression levels of VCAM-1 and ICAM-1 in the vasculature at 16 wks of age. However, there was no difference between the two groups, suggesting that uninephrectomy did not effect on either western diet-induced mobilization of bone marrow-derived monocytes or endothelial activation in the early stage of atherosclerosis. We therefore focused on the PVAT surrounding the thoracic aorta, which showed multilocular fat droplet and high expression levels of brown adipocyte-specific genes. The fat pad weight and cross-sectional area of PVAT including the infiltration of CD45+ cells did not differ between the two groups. While mRNA expression levels of adipocyte differentiation marker genes (PPARγ, FABP4, and adiponectin) were equivalent between the two groups, brown adipocyte-specific marker genes (UCP-1, Elovl3) showed a significantly lower expression in UNX mice (P<0.01). In contrast, white adipocyte-specific marker gene Tcf21 was markedly up-regulated (101%, P<0.05), accompanied by the increased expression of angiotensinogen gene (85%, P<0.05). The concentration of serum angiotensin II did not differ between the two groups.

CONCLUSION: Phenotypic conversion of perivascular brown to white adipose tissue along with the depot-specific local activation of renin-angiotensin system is a possible mechanism underlying the early stage of atherosclerosis in CKD.

Abstract 528: Bone Marrow Angiotensin AT2 Receptor Deficiency Aggravates Atherosclerosis by Eliminating Macrophage Liver X Receptor-Mediated Antiatherogenic Actions

[BACKGROUND] The angiotensin II (Ang II) type 2 (AT2) receptor is crucially involved in atherogenesis; however, bone marrow (BM) AT2-mediated anti-atherogenic action remains undefined.

[METHOD AND RESULT] We generated BM chimera apoE-deficient (apoE-/-) mice whose BM cells were repopulated with AT2-deficient (Agtr2-/-) or wild type (Agtr2+/+) cells. Eight weeks after BM transplantation, all mice were fed a western diet for two months. Atherosclerotic lesion area was significantly increased in apoE-/-/BM-Agtr2 -/- mice compared with apoE-/-/BM-Agtr2+/+ mice (51%, P<0.05), accompanied by the enhanced accumulation of MOMA-2 positive cells (P<0.05). Hemodynamic data and lipid profile did not differ between the two groups. We first examined the expression levels of macrophage liver X receptors (LXRα and β), which have been reported to exert anti-atherogenic actions by reducing pro-inflammatory response and promoting cholesterol efflux and macrophage emigration. The mRNA expression of LXRβ, but not LXRα, was significantly decreased by 21% in Agtr2 -/- thioglycollate-induced peritoneal macrophages (TGPM) compared with Agtr2+/+ TGPM (P<0.01). Inversely, LXRβ mRNA expression was markedly increased by co-treatment of angiotensin II (100nM) with AT1 receptor blocker, Olmesartan (10μM) (47%, p<0.01). Treatment with LXR agonist (GW3965) significantly attenuated LPS-induced mRNA expressions of TNF-α and IL-1β in Agtr2+/+ TGPM (35%, 46%, respectively, P<0.01), however, anti-inflammatory effect of LXR agonist was markedly reduced in Agtr2 -/- TGPM (p<0.05). Furthermore, the expression levels of ATP-binding cassette transporter ABCA1 and CCR7, essentially implicated in cholesterol efflux and macrophage emigration, were much lower in Agtr2 -/- TGPM than Agtr2+/+ TGPM (34%, 53%, p<0.01). Flow cytometric analysis also showed a significantly lower expression of CCR7 in Agtr2 -/- TGPM (24%, p<0.05).

[CONCLUSION] Our findings demonstrate that BM-AT2 deficiency aggravates atherosclerosis, at least in part, by eliminating anti-atherogenic properties elicited by macrophage LXR activation, suggesting that AT2-mediated regulation of macrophage LXR activity could be a novel therapeutic target for the prevention of atherosclerosis.

p53 Promotes Cardiac Dysfunction in Diabetic Mellitus Caused by Excessive Mitochondrial Respiration-Mediated Reactive Oxygen Species Generation and Lipid Accumulation

Background—

Diabetic cardiomyopathy is characterized by energetic dysregulation caused by glucotoxicity, lipotoxicity, and mitochondrial alterations. p53 and its downstream mitochondrial assembly protein, synthesis of cytochrome c oxidase 2 (SCO2), are important regulators of mitochondrial respiration, whereas the involvement in diabetic cardiomyopathy remains to be determined.

Methods and Results—

The role of p53 and SCO2 in energy metabolism was examined in both type I (streptozotocin [STZ] administration) and type II diabetic ( db/db ) mice. Cardiac expressions of p53 and SCO2 in 4-week STZ diabetic mice were upregulated (185% and 152% versus controls, respectively, P <0.01), with a marked decrease in cardiac performance. Mitochondrial oxygen consumption was increased (136% versus control, P <0.01) in parallel with augmentation of mitochondrial cytochrome c oxidase (complex IV) activity. Reactive oxygen species (ROS)-damaged myocytes and lipid accumulation were increased in association with membrane-localization of fatty acid translocase protein FAT/CD36. Antioxidant tempol reduced the increased expressions of p53 and SCO2 in STZ-diabetic hearts and normalized alterations in mitochondrial oxygen consumption, lipid accumulation, and cardiac dysfunction. Similar results were observed in db/db mice, whereas in p53-deficient or SCO2-deficient diabetic mice, the cardiac and metabolic abnormalities were prevented. Overexpression of SCO2 in cardiac myocytes increased mitochondrial ROS and fatty acid accumulation, whereas knockdown of SCO2 ameliorated them.

Conclusions—

Myocardial p53/SCO2 signal is activated by diabetes-mediated ROS generation to increase mitochondrial oxygen consumption, resulting in excessive generation of mitochondria-derived ROS and lipid accumulation in association with cardiac dysfunction.

Dehydroxymethylepoxyquinomicin (DHMEQ) can suppress tumour necrosis factor-α production in lipopolysaccharide-injected mice, resulting in rescuing mice from death in vivo

Dehydroxymethylepoxyquinomicin (DHMEQ), a new nuclear factor (NF)-κB inhibitor, has several beneficial effects, including the suppression of tumour growth and anti-inflammatory effects. DHMEQ can also suppress the production of tumour necrosis factor (TNF)-α induced by lipopolysaccharide (LPS) in vitro. In the present study, we examine the effects of DHMEQ on TNF-α production in vivo and on the survival of mice injected with LPS. When DHMEQ was injected into mice 2 h before LPS injection, the survival of the LPS-injected mice was prolonged. When DHMEQ was injected twice (2 h before LPS injection and the day after LPS injection), all the mice were rescued. The injection of DHMEQ 1 h after LPS injection and the day after LPS injection also resulted in the rescue of all mice. The serum levels of TNF-α in the mice that received both LPS and DHMEQ were suppressed compared to the mice that received only LPS. These results suggest that DHMEQ can be utilized for the prevention and treatment of endotoxin shock.

Loss of bcl-2 during the senescence exacerbates the impaired angiogenic functions in endothelial cells by deteriorating the mitochondrial redox state

Ageing is an important risk factor for ischemic cardiovascular diseases, although its underlying molecular mechanisms remain to be elucidated. Here, we report a crucial role of Bcl-2 in the impaired angiogenic functions in senescent endothelial cells (ECs) by modulating the mitochondrial redox state. Cellular senescence impaired angiogenic functions in ECs without attenuating the mitogen-activated protein kinase or Akt signaling, and vascular endothelial growth factor receptor 2 or Tie-2 expressions. We identified that Bcl-2 expression was markedly reduced in 3 independent models for senescent ECs, and pharmacological inhibition, as well as small interfering RNA-mediated gene silencing of Bcl-2, significantly impaired the angiogenic functions in young ECs. Bcl-2 has an antioxidative role by locating the glutathione at mitochondria, and we found that mitochondrial oxidative stress was significantly augmented in senescent ECs, in association with reduced mitochondria-associated glutathione. Transfection of Bcl-2 in senescent ECs significantly reduced the mitochondrial oxidative stress, restored the mitochondrial membrane potential, and improved the angiogenic capacity. Furthermore, gene transfer of Bcl-2 using adenovirus significantly improved the in vivo angiogenesis in the Matrigel plugs implanted into aged mice, whereas the Bcl-2 inhibitor reduced the angiogenesis in the Matrigel plugs implanted into young mice. Together, Bcl-2 plays a crucial role in the regulation of the mitochondrial redox state in ECs, and, thus, loss of Bcl-2 during the senescence exacerbates the impaired angiogenesis by augmenting the mitochondrial oxidative stress.

A case of Goodpasture syndrome positive for anti-GBM antibody and MPO-ANCA complicated by a variety of serious infections

A 62-year-old female was admitted to our hospital for investigation of acute progressive renal insufficiency and a systemic inflammatory reaction, despite treatment with several antibiotics. Laboratory data revealed severe renal insufficiency and positive titers for the myeloperoxidase anti-neutrophil cytoplasmic and anti-glomerular basement membrane antibodies. The deterioration of her general status did not allow us to perform the renal biopsy. Although corticosteroid therapy, hemodialysis, and plasma exchange were concomitantly initiated, pulmonary hemorrhage occurred several days after admission. Mechanical ventilation support was provided and continuous hemodiafiltration was carried out, following which the respiratory failure improved immediately. However, she developed clinical depression and suicidal behavior under the intensive therapy. Therefore, plasma exchange was discontinued and corticosteroid was tapered as quickly as possible. Four months after admission, platelet transfusion and short-term mechanical ventilation support improved the pulmonary hemorrhage; however, her mental status deteriorated despite psychiatric consultation and treatment with a tranquilizer. Thereafter, severe and serious systemic infection due to various pathogens including Staphylococcus aureus, Cytomegalovirus, Pneumocystis jiroveci, Pseudomonas aeruginosa, and Bacteroides recurred, and she died from systemic invasive aspergillosis (IA). We suspected severe immunosuppression caused by various factors, such as predonisolone administration, chronic renal failure on maintenance hemodialysis, depression, and malnutrition due to chronic inflammation and granulocytopenia as a side effect of ganciclovir. When treating rapidly progressive glomerulonephritis, immunosuppressive status should be carefully monitored regarding not only the dosage of therapeutic regimen but also the mental health status and nutrition of the patient.

Early inflammatory reactions in atherosclerosis are induced by proline-rich tyrosine kinase/reactive oxygen species-mediated release of tumor necrosis factor-alpha and subsequent activation of the p21Cip1/Ets-1/p300 system

OBJECTIVE

Reactive oxygen species (ROS) are involved in the initial process of atherosclerosis, whereas it remains to be determined how atherogenic stimulus causes ROS-mediated proinflammatory reactions. Here, we focused on proline-rich tyrosine kinase (PYK2)-mediated ROS generation and examined how atherogenic stimulus causes early proinflammatory reactions.

METHODS AND RESULTS

PYK2-deficient (knockout [KO]) (PYK2-KO) mice were crossbred with apolipoprotein E (ApoE)-deficient (PYK2-KO/ApoE-KO) mice. PYK2-KO/ApoE-KO mice and endothelial cells (EC) were used for the study. Aortic atherogenic lesions in PYK2-KO/ApoE-KO mice were markedly decreased (55% versus ApoE-KO) after 8 weeks of a Western diet. Aortic PYK2 was activated as early as 7 days after the Western diet, when inflammatory cells were not yet activated. Addition of the proatherogenic oxidized phospholipid lysophosphatidylcholine caused activation of endothelial PYK2. Lysophosphatidylcholine-activated PYK2 induced NADPH oxidase-mediated ROS generation and ROS-mediated synthesis of tumor necrosis factor-α (TNFα), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemotactic protein-1 (MCP-1), and p21Cip1/Ets-1. Neutralizing anti-TNFα antibody or knockdown of p21Cip1/Ets-1 system blocked the induction of VCAM-1 and MCP-1. PYK2 deficiency abolished these ROS-mediated proinflammatory reactions. Further analysis revealed that PYK2/ROS-mediated p21Cip1/Ets-1 activation upregulated the transcription of the MCP-1 gene in collaboration with p300 transcription coactivator.

CONCLUSIONS

PYK2 is a key tyrosine kinase activated by high cholesterol exposure, which causes ROS-mediated TNFα release and induces TNFα-dependent expression of proinflammatory molecules via the p21Cip1/Ets-1/p300 transcription system.

Endothelial FGF receptor signaling accelerates atherosclerosis

Members of the fibroblast growth factor (FGF) family have been clinically applied to the treatment of ischemic diseases because of their strong angiogenic actions. Although tissue ischemia is predominantly caused by atherosclerosis, the roles of endothelial FGF receptors (FGF-Rs) in atherosclerosis remain obscure. We generated endothelial cell (EC)-targeted constitutively active FGF-R2-overexpressing mice, using the Tie2 promoter (Tie2-FGF-R2-Tg), and crossed them with apolipoprotein E (ApoE)-deficient mice (ApoE-KO) to generate Tie2-FGF-R2-Tg/ApoE-deficient mice (Tie2-FGF-R2-Tg/ApoE-KO). After being fed a Western diet for 8 wk, the Tie2-FGF-R2-Tg/ApoE-KO demonstrated 2.0-fold greater atherosclerotic lesion area on the luminal surfaces of the aortas than the ApoE-KO (P < 0.01). The level of p21(Cip1) protein, a cell cycle inhibitor, in the FGF-R2-overexpressing EC was 2.5-fold greater than that in the wild-type (WT) EC at the baseline (P < 0.01). FGF-R2 overexpression in the EC resulted in increased expression of VCAM-1 and ICAM-1, acceleration of apoptosis, and decreased proliferative activity, all of which were normalized by small interfering RNA (siRNA)-mediated knockdown of p21(Cip1) (75% reduction in protein level, P < 0.01). Furthermore, the expression of PDGF-B and Egr-1, a PDGF/p21(Cip1)-inducible transcription factor, in the aortic endothelium of Tie2-FGF-R2-Tg/ApoE-KO was significantly greater than that in ApoE-KO. The proliferation of vascular smooth muscle cells in the aortic media of Tie2-FGF-R2-Tg/ApoE-KO was 2.0-fold higher than that in ApoE-KO (P < 0.01). Thus our study reveals that endothelial FGF-R2 signaling aggravates atherosclerosis by promoting p21(Cip1)-mediated EC dysfunction and cautions against the use of FGF for therapeutic angiogenesis in the setting of atherosclerosis.

p53 and TIGAR regulate cardiac myocyte energy homeostasis under hypoxic stress

Bioenergetic homeostasis is altered in heart failure and may play an important role in pathogenesis. p53 has been implicated in heart failure, and although its role in regulating tumorigenesis is well characterized, its activities on cellular metabolism are just beginning to be understood. We investigated the role of p53 and its transcriptional target gene TP53-induced glycolysis and apoptosis regulator (TIGAR) in myocardial energy metabolism under conditions simulating ischemia that can lead to heart failure. Expression of p53 and TIGAR was markedly upregulated after myocardial infarction, and apoptotic myocytes were decreased by 42% in p53-deficient mouse hearts compared with those in wild-type mice. To examine the effect of p53 on energy metabolism, cardiac myocytes were exposed to hypoxia. Hypoxia induced p53 and TIGAR expression in a p53-dependent manner. Knockdown of p53 or TIGAR increased glycolysis with elevated fructose-2,6-bisphosphate levels and reduced myocyte apoptosis. Hypoxic stress decreased phosphocreatine content and the mitochondrial membrane potential of myocytes without changes in ATP content, the effects of which were prevented by the knockdown of TIGAR. Inhibition of glycolysis by 2-deoxyglucose blocked these bioenergetic effects and TIGAR siRNA-mediated prevention of apoptosis, and, in contrast, overexpression of TIGAR reduced glucose utilization and increased apoptosis. Our data demonstrate that p53 and TIGAR inhibit glycolysis in hypoxic myocytes and that inhibition of glycolysis is closely involved in apoptosis, suggesting that p53 and TIGAR are significant mediators of cellular energy homeostasis and cell death under ischemic stress.

Signaling from fibroblast growth factor receptor 2 in immature hematopoietic cells facilitates donor hematopoiesis after intra-bone marrow-bone marrow transplantation

Fibroblast growth factor (FGF) and FGF receptor (FGFR) are expressed in various cells including endothelial progenitor cells and hematopoietic cells. The interaction between FGF and FGFR is associated with the proliferation, migration, and survival of these cells. In this report, we examined the effects of FGFR2 signaling on hematopoiesis in immature hematopoietic cells, using mutant mice in which a constitutively active form of FGFR2 mutant was caused to be overexpressed by the Tie2 promoter (FGFR2 Tg mice). Under normal conditions, hematopoiesis of FGFR2 Tg mice and wild type (Wt) mice do not differ significantly, except for the weight and cell numbers of the thymus. However, the c-kit(+)Sca-1(+)lineage⁻ bone marrow cells (BMCs) of FGFR2 Tg mice facilitate the formation of colony-forming units of culture. When these BMCs were transplanted into the recipient bone marrow (intra-bone marrow-bone marrow transplantation), there was better reconstitution of donor hematopoietic cells. In the in vitro experiment, the c-kit(+)Sca-1(+)lineage⁻ BMCs from FGFR2 Tg mice showed fewer apoptotic cells than those from Wt mice. These results suggest that the antiapoptotic effect of FGFR2 signaling facilitates the hematopoiesis of FGFR2 Tg mice.

Decreased plasma level of vitamin C in chronic kidney disease: comparison between diabetic and non-diabetic patients

BACKGROUND

A decreased plasma level of vitamin C has been reported to be associated with an increased risk of cardiovascular morbidity and mortality. Here, we sought to determine the vitamin C status of patients with chronic kidney disease and the pathophysiological role of vitamin C in these patients.

METHODS

We studied 58 patients and evaluated the relationship between renal function and plasma vitamin C concentration, as well as the effect of diabetes on this relationship. Endothelium-dependent flow-mediated dilation of brachial artery was measured to assess the endothelial function. Serum malondialdehyde low-density lipoprotein was measured as a marker for oxidative stress.

RESULTS

Plasma vitamin C concentration had a positive linear relationship with eGFR in both diabetic and non-diabetic patients (P = 0.006 and P = 0.004, respectively). When vitamin C concentration and eGFR relationships were compared in the two groups, vitamin C concentration was significantly lower in diabetic patients at every eGFR (P = 0.006). Flow-mediated vasodilatation of the brachial artery was positively correlated with vitamin C concentration in non-diabetic patients (P = 0.047) but not in diabetic patients. There was a negative correlation between serum malondialdehyde low-density lipoprotein and vitamin C concentration in non-diabetic patients (P = 0.044) but not in diabetic patients.

CONCLUSIONS

Renal dysfunction was associated with a decrease in plasma vitamin C level. Moreover, decreased vitamin C may cause endothelial dysfunction via an increase in oxidative stress in non-diabetic chronic kidney disease patients.

Caspase inhibitor ZVAD-fmk facilitates engraftment of donor hematopoietic stem cells in intra-bone marrow-bone marrow transplantation

When bone marrow transplantation (BMT) is carried out, survival of the donor hematopoietic stem cells is crucial to maintain donor hematopoiesis in the recipients. We have shown that intra-bone marrow-bone marrow transplantation (IBM-BMT) can induce the rapid recovery of donor hematopoiesis and allow a reduction in radiation doses as a pretreatment for BMT. If IBM-BMT methodology can be further improved, BMT could be carried out more safely and more easily. In this experiment, we attempted to suppress apoptosis of donor hematopoietic cells using a caspase inhibitor, ZVAD-fmk, upon IBM-BMT in mouse allogeneic IBM-BMT. IBM-BMT with ZVAD-fmk induced superior engraftment of donor hematopoietic cells and greater numbers of day-12 colony-forming units of spleen (CFU-S) than IBM-BMT without ZVAD-fmk upon allogeneic BMT (C57BL/6 into BALB/c mice). ZVAD-fmk slightly suppressed apoptosis of whole BMCs, whereas it significantly suppressed apoptosis of c-kit+/Sca-1+/lineage(-) cells (KSL cells) in vitro. These results suggest that ZVAD-fmk can suppress apoptosis of hematopoietic stem cells and/or immature progenitor cells of the donor bone marrow cells, thereby accelerating the donor hematopoiesis.

Paracrine osteogenic signals via bone morphogenetic protein-2 accelerate the atherosclerotic intimal calcification in vivo

OBJECTIVE

Vascular calcification is an important risk factor for cardiovascular diseases. Here, we investigated a role of dedifferentiated vascular smooth muscle cells (VSMCs) in the atherosclerotic intimal calcification.

METHODS AND RESULTS

We prepared human cultured VSMCs in either redifferentiatiated or dedifferentiated state and analyzed the gene expressions of bone-calcification regulatory factors. Expression of bone morphogenetic protein-2 (BMP-2), a potent initiator for osteoblast differentiation, was significantly enhanced in dedifferentiated VSMCs. Furthermore, endogenous BMP-2 antagonists, such as noggin, chordin, and matrix gamma-carboxyglutamic acid protein, were all downregulated in the dedifferentiated VSMCs. Conditioned medium from dedifferentiated VSMCs, but not from redifferentiated VSMCs, stimulated the osteoblastic differentiation of the mesenchymal progenitor C2C12 cells, which was abolished by BMP-2 knockdown. In atherosclerotic intima from apolipoprotein (apo)E-deficient mice, αSM-actin-positive cells, presumably dedifferentiated VSMCs, expressed BMP-2. We generated BMP-2-transgenic mice using αSM-actin promoter and crossed them with apoE-deficient mice (BMP-2-transgenic/apoE-knockout). Significantly accelerated atherosclerotic intimal calcification was detected in BMP-2-transgenic/apoE-knockout mice, although serum lipid concentration and atherosclerotic plaque size were not different from those in apoE-knockout mice. Enhanced calcification appeared to be associated with the frequent emergence of osteoblast-like cells in atherosclerotic intima in BMP-2-transgenic/apoE-knockout mice.

CONCLUSIONS

Our findings collectively demonstrate an important role of dedifferentiated VSMCs in the pathophysiology of atherosclerotic calcification through activating paracrine BMP-2 osteogenic signals.

Bone Marrow AT 1 Augments Neointima Formation by Promoting Mobilization of Smooth Muscle Progenitors via Platelet-Derived SDF-1α

Objectives— Bone marrow (BM)-derived endothelial progenitor cells (EPCs) and vascular smooth muscle progenitor cells (VPCs) contribute to neointima formation, whereas the angiotensin II (Ang II) type 1 receptor (AT 1 )-mediated action on BM-derived progenitors remains undefined.

Methods and Results— A wire-induced vascular injury was performed in the femoral artery of BM-chimeric mice whose BM was repopulated with AT 1 -deficient (BM-Agtr1 −/− ) or wild-type (BM-Agtr1 +/+ ) cells. Neointima formation was profoundly reduced by 38% in BM-Agtr1 −/− mice. Although the number of circulating EPCs (Sca-1 + Flk-1 + ) and extent of reendothelialization did not differ between the 2 groups, the numbers of both circulating VPCs (c-Kit − Sca-1 + Lin − ) and tissue VPCs (Sca-1 + CD31 − ) incorporated into neointima were markedly decreased in BM-Agtr1 −/− mice. The accumulation of aggregated platelets and their content of stromal cell–derived factor-1α (SDF-1α) were significantly reduced in BM-Agtr1 −/− mice, accompanied by a decrease in the serum level of SDF-1α. Thrombin-induced platelets aggregation was dose-dependently inhibited (45% at 0.1 IU/mL, P <0.05) in Agtr1 −/− platelets compared with Agtr1 +/+ platelets, accompanied by the reduced expression and release of SDF-1α.

Conclusions— The BM-AT 1 receptor promotes neointima formation by regulating the mobilization and homing of BM-derived VPCs in a platelet-derived SDF-1α–dependent manner without affecting EPC-mediated reendothelialization.

Replicative senescence of vascular smooth muscle cells enhances the calcification through initiating the osteoblastic transition

Medial artery calcification, which does not accompany lipid or cholesterol deposit, preferentially occurs in elderly population, but its underlying mechanisms remain unclear. In the present study, we investigated the potential role of senescent vascular smooth muscle cells (VSMCs) in the formation of senescence-associated medial calcification. Replicative senescence was induced by the extended passages (until passages 11-13) in human primary VSMCs, and cells in early passage (passage 6) were used as control young cells. VSMC calcification was markedly enhanced in the senescent cells compared with that in the control young cells. We identified that genes highly expressed in osteoblasts, such as alkaline phosphatase (ALP) and type I collagen, were significantly upregulated in the senescent VSMCs, suggesting their osteoblastic transition during the senescence. Knockdown of either ALP or type I collagen significantly reduced the calcification in the senescent VSMCs. Of note, runt-related transcription factor-2 (RUNX-2), a core transcriptional factor that initiates the osteoblastic differentiation, was also upregulated in the senescent VSMCs. Knockdown of RUNX-2 significantly reduced the ALP expression and calcification in the senescent VSMCs, suggesting that RUNX-2 is involved in the senescence-mediated osteoblastic transition. Furthermore, immunohistochemistry of aorta from the klotho(-/-) aging mouse model demonstrated in vivo emergence of osteoblast-like cells expressing RUNX-2 exclusively in the calcified media. We also found that statin and Rho-kinase inhibitor effectively reduced the VSMC calcification by inhibiting P(i)-induced apoptosis and potentially enhancing matrix Gla protein expression in the senescent VSMCs. These findings strongly suggest an important role of senescent VSMCs in the pathophysiology of senescence-associated medial calcification, and the inhibition of osteoblastic transition could be a new therapeutic approach for the prevention of senescence-associated medial calcification.

Pressure-mediated hypertrophy and mechanical stretch induces IL-1 release and subsequent IGF-1 generation to maintain compensative hypertrophy by affecting Akt and JNK pathways

RATIONALE

It has been reported that interleukin (IL)-1 is associated with pathological cardiac remodeling and LV dilatation, whereas IL-1beta has also been shown to induce cardiomyocyte hypertrophy. Thus, the role of IL-1 in the heart remains to be determined.

OBJECTIVE

We studied the role of hypertrophy signal-mediated IL-1beta/insulin-like growth factor (IGF)-1 production in regulating the progression from compensative pressure-mediated hypertrophy to heart failure.

METHODS AND RESULTS

Pressure overload was performed by aortic banding in IL-1beta-deficient mice. Primarily cultured cardiac fibroblasts (CFs) and cardiac myocytes (CMs) were exposed to cyclic stretch. Heart weight, myocyte size, and left ventricular ejection fraction were significantly lower in IL-1beta-deficient mice (20%, 23% and 27%, respectively) than in the wild type 30 days after aortic banding, whereas interstitial fibrosis was markedly augmented. DNA microarray analysis revealed that IGF-1 mRNA level was markedly (approximately 50%) decreased in the IL-1beta-deficient hypertrophied heart. Stretch of CFs, rather than CMs, abundantly induced the generation of IL-1beta and IGF-1, whereas such IGF-1 induction was markedly decreased in IL-1beta-deficient CFs. IL-1beta released by stretch is at a low level unable to induce IL-6 but sufficient to stimulate IGF-1 production. Promoter analysis showed that stretch-mediated IL-1beta activates JAK/STAT to transcriptionally regulate the IGF-1 gene. IL-1beta deficiency markedly increased c-Jun N-terminal kinase (JNK) and caspase-3 activities and enhanced myocyte apoptosis and fibrosis, whereas replacement of IGF-1 or JNK inhibitor restored them.

CONCLUSIONS

We demonstrate for the first time that pressure-mediated hypertrophy and mechanical stretch generates a subinflammatory low level of IL-1beta, which constitutively causes IGF-1 production to maintain adaptable compensation hypertrophy and inhibit interstitial fibrosis.

Bone marrow angiotensin AT1 receptor regulates differentiation of monocyte lineage progenitors from hematopoietic stem cells

BACKGROUND

The angiotensin II (Ang II) type 1 (AT(1)) receptor is expressed in bone marrow (BM) cells, whereas it remains poorly defined how Ang II regulates differentiation/proliferation of monocyte-lineage cells to exert proatherogenic actions.

METHODS AND RESULTS

We generated BM chimeric apoE(-/-) mice repopulated with AT(1)-deficient (Agtr1(-/-)) or wild-type (Agtr1(+/+)) BM cells. The atherosclerotic development was significantly reduced in apoE(-/-)/BM-Agtr1(-/-) mice compared with apoE(-/-)/BM-Agtr1(+/+) mice, accompanied by decreased numbers of BM granulocyte/macrophage progenitors (GMP:c-Kit(+)Sca-1(-)Lin(-)CD34(+)CD16/32(+)) and peripheral blood monocytes. Macrophage-colony-stimulating factor (M-CSF)-induced differentiation from hematopoietic stem cells (HSCs:c-Kit(+)Sca-1(+)Lin(-)) to promonocytes (CD11b(high)Ly-6G(low)) was markedly reduced in HSCs from Agtr1(-/-) mice. The expression of M-CSF receptor c-Fms was decreased in HSCs/promonocytes from Agtr1(-/-) mice, accompanied by a marked inhibition in M-CSF-induced phosphorylation of PKC-delta and JAK2. c-Fms expression in HSCs/promonocytes was mainly regulated by TNF-alpha derived from BM CD45(-)CD34(-) stromal cells, and Ang II specifically regulated the TNF-alpha synthesis and release from BM stromal cells.

CONCLUSIONS

Ang II regulates the expression of c-Fms in HSCs and monocyte-lineage cells through BM stromal cell-derived TNF-alpha to promote M-CSF-induced differentiation/proliferation of monocyte-lineage cells and contributes to the proatherogenic action.

Histamine ameliorates anti-glomerular basement membrane antibody-induced glomerulonephritis in rats

Anti-glomerular basement membrane (anti-GBM)-induced glomerulonephritis involves T-helper type 1 (Th1) responses leading to rapid crescent formation. As many inflammatory and immune responses in general are affected by histamine, we examined the effects of histaminergic ligands on immune renal injury in the rat. Female Wistar-Kyoto rats were injected intraperitoneally with an antibody against the GBMs. Histaminergic ligands were then injected twice daily for 5 days after which renal function was assessed by proteinuria. Treatment with histamine led to significant dose-dependent reductions in proteinuria compared to the control antibody-injected group and markedly decreased the number of crescentic glomeruli and macrophage infiltration of the glomeruli. Furthermore, histamine significantly decreased the plasma concentration of interleukin-12, a Th1-type cytokine compared to the antibody-injected control animals. Dimaprit, an H(2)/H(4) agonist, mimicked the effects of histamine on proteinuria and crescent formation. Clozapine, an H(4) agonist, tended to mimic the effects of histamine, whereas an H(1), mepyramine, or an H(2) antagonist, ranitidine, did not reverse the protective effect of histamine. We suggest that histamine may alleviate renal injury in anti-GBM glomerulonephritis by suppressing the immune response.

Central Role of Calcium-Dependent Tyrosine Kinase PYK2 in Endothelial Nitric Oxide Synthase–Mediated Angiogenic Response and Vascular Function

Background— The involvement of Ca 2+ -dependent tyrosine kinase PYK2 in the Akt/endothelial NO synthase pathway remains to be determined.

Methods and Results— Blood flow recovery and neovessel formation after hind-limb ischemia were impaired in PYK2 −/− mice with reduced mobilization of endothelial progenitors. Vascular endothelial growth factor (VEGF)–mediated cytoplasmic Ca 2+ mobilization and Ca 2+ -independent Akt activation were markedly decreased in the PYK2-deficient aortic endothelial cells, whereas the Ca 2+ -independent AMP-activated protein kinase/protein kinase-A pathway that phosphorylates endothelial NO synthase was not impaired. Acetylcholine-mediated aortic vasorelaxation and cGMP production were significantly decreased. Vascular endothelial growth factor–dependent migration, tube formation, and actin cytoskeletal reorganization associated with Rac1 activation were inhibited in PYK2-deficient endothelial cells. PI3-kinase is associated with vascular endothelial growth factor–induced PYK2/Src complex, and inhibition of Src blocked Akt activation. The vascular endothelial growth factor–mediated Src association with PLCγ1 and phosphorylation of 783 Tyr-PLCγ1 also were abolished by PYK2 deficiency.

Conclusion— These findings demonstrate that PYK2 is closely involved in receptor- or ischemia-activated signaling events via Src/PLCγ1 and Src/PI3-kinase/Akt pathways, leading to endothelial NO synthase phosphorylation, and thus modulates endothelial NO synthase–mediated vasoactive function and angiogenic response.

Renal involvement in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary systemic arteriopathy presenting with migraines, mood disorders, focal neurologic deficits, recurrent ischemic attacks and dementia in young adults. The genesis of this disease relates to missense mutation of the Notch3 gene. We report here a newly identified CADASIL patient and discuss unique vascular lesions observed in the kidney. A 64-year-old female was admitted to our hospital for the investigation of proteinuria, hematuria and progressive neurological abnormalities. Her mother and brother died of cerebral infarction at a relatively young age despite a lack of apparent risk factors for arteriosclerosis. Over the past 4 months before admission, she had suffered from frequent transient ischemic attacks despite appropriate antiplatelet therapy. Blood examination revealed mild renal insufficiency and urinalysis revealed moderate protein excretion and dysmorphic hematuria. Magnetic resonance imaging of the brain revealed multiple infarcts and leukoencephalopathy. Histopathological analysis of the kidney revealed focal segmental mesangial proliferation, the loss and degeneration of arterial medial smooth muscle cells and arterial intimal thickening. Immunofluorescence analysis of glomeruli revealed IgA deposition in the mesangial area. Electron microscope analysis revealed electron-dense deposition also in the mesangial area. In addition, granular osmophilic material (GOM) was observed in the extraglomerular mesangial area and around the vascular smooth muscle cells. Genetic analysis of Notch3 revealed an R141C missense mutation and she was diagnosed with CADASIL complicated with IgA nephropathy. In immunohistological analysis, Notch3 stains were positive in vascular smooth muscle cells of the interlobular arteries and both afferent and efferent arterioles, and weak in the glomerular mesangial area. Antihypertensive treatment using angiotensin II receptor blocker and a low protein diet were initiated, and her urinary protein excretion decreased to 0.2 g/day. However, due to the progression of her neurological abnormalities, she became socially withdrawn. In CADASIL, GOM, abnormal accumulation of Notch3 ectodomain, is thought to induce the degeneration and loss of vascular smooth muscle cells and subsequent intimal thickening. Analysis of our cases provided that these morphological abnormalities were also observed in the CADASIL patient kidney.

Novel transcripts of Nox1 are regulated by alternative promoters and expressed under phenotypic modulation of vascular smooth muscle cells

NADPH oxidase is implicated in the pathogenesis of various cardiovascular disorders. In vascular smooth muscle cells (VSMC), expression of NOX1 (NADPH oxidase 1), a catalytic subunit of NADPH oxidase, is low and is induced upon stimulation by vasoactive factors, while it is abundantly expressed in colon epithelial cells. To clarify the regulatory mechanisms underlying such cell-specific expression, the upstream regions directing transcription of the NOX1 gene were explored. In P53LMACO1 cells, a cell line originated from mouse VSMCs, two novel Nox1 mRNA species, the c- and f-type, were isolated. These transcripts contained 5'-untranslated regions that differed from the colon type mRNA (a-type) and encoded an additional N-terminal peptide of 28 amino acids. When these transcripts were fused to the c-myc tag and expressed in human embryonic kidney 293 cells, a fraction of translated proteins demonstrated the size containing the additional peptide. Proteins encoded by the c- and f-type mRNAs exhibited superoxide-producing activities equivalent to the activity of the a-type form. The a-type mRNA was expressed in the colon and in the intact aorta, whereas the c-type mRNA was detected in the primary cultured VSMCs migrated from aortic explants, in vascular tissue of a wire-injury model and in the thoracic aorta of mice infused with angiotensin II. The promoter region of the c-type mRNA exhibited transcriptional activity in P53LMACO1 cells, but not in MCE301 cells, a mouse colon epithelial cell line. These results suggest that expression of the Nox1 gene is regulated by alternative promoters and that the novel c-type transcript is induced under phenotypic modulation of VSMCs.

Myocardium-targeted delivery of endothelial progenitor cells by ultrasound-mediated microbubble destruction improves cardiac function via an angiogenic response

Application of ultrasound-mediated destruction of microbubbles (US + Bubble) to skeletal muscle creates capillary ruptures leading to leakage of the cell components. We studied whether US + Bubble combined with bone-marrow-derived mononuclear cells (BM-MNCs) infusion enables the targeted delivery of endothelial-lineage cells into the myocardium and improves cardiac function of the cardiomyopathy model due to the paucity of neocapillary formation. Pulsed US was applied to the anterior chest of BIOTO2 cardiomyopathy hamsters for 90 s after the intravenous injection of microbubble (Optison) followed by infusion of BM-MNCs. Cardiac samples from US + microbubble + BM-MNCs (US + Bubble + BM), US + Bubble, US + BM without Bubble, and saline infusion control groups were analyzed 12 weeks after treatment. Labeled BM-MNCs transplanted by US + Bubble were found to be mainly localized in the microvessels, but not by US stimulation without microbubble (121.2 +/- 24.5 vs. 2.80 +/- 1.30 cells/mm2, P < 0.001). Capillary densities in US + Bubble + BM group were increased 1.7-fold (P < 0.05) over the control, and neither US + Bubble nor US + BM enhanced neocapillary formation. 99mTc-Tetrofosmin scintigraphy revealed that blood perfusion area in the US + Bubble + BM group was 48% greater than the control (P < 0.01). US + Bubble stimulation induces the expression of adhesion molecules (VCAM-1 and ICAM-1) in capillaries, and the US + Bubble-mediated supply of BM-MNCs increased the myocardial content of VEGF and bFGF. The left ventricular wt/body wt, area of cardiac fibrosis, and apoptotic cell numbers in the US + Bubble + BM group significantly (P < 0.05) decreased by 82%, 73%, and 64% relative to the control, respectively. The cardiac function in myopathic hamsters (assessed by fractional shortening) was markedly improved 36% (P < 0.05) by US + Bubble + BM treatment. Targeted delivery of BM-MNCs by US + Bubble to the myocardium of the cardiomyopathic hamster increased the capillary densities and regional blood flow and inhibited cardiac remodeling, resulting in the prevention of heart failure. This non-invasive cell delivery system may be useful as a novel efficient approach for angiogenic cell therapy to the myocardium.

Erythropoietin-mobilized endothelial progenitors enhance reendothelialization via Akt-endothelial nitric oxide synthase activation and prevent neointimal hyperplasia

We investigated whether the mobilization of endothelial progenitor cells (EPCs) by exogenous erythropoietin (Epo) promotes the repair of injured endothelium. Recombinant human Epo was injected (1000 IU/kg for the initial 3 days) after wire injury of the femoral artery of mice. Neointimal formation was inhibited by Epo to 48% of the control (P<0.05) in an NO-dependent manner. Epo induced a 1.4-fold increase in reendothelialized area of day 14 denuded vessels, 55% of which was derived from bone marrow (BM) cells. Epo increased the circulating Sca-1(+)/Flk-1(+) EPCs (2.0-fold, P<0.05) with endothelial properties NO dependently. BM replacement by GFP- or beta-galactosidase-overexpressing cells showed that Epo stimulated both differentiation of BM-derived EPCs and proliferation of resident ECs. BM-derived ECs increased 2.2- to 2.7-fold (P<0.05) in the Epo-induced neoendothelium, where the expression of Epo receptor was upregulated. Epo induced Akt/eNOS phosphorylation and NO synthesis on EPCs and exerted an antiapoptotic action on wire-injured arteries. In conclusion, Epo treatment inhibits the neointimal hyperplasia after arterial injury in an NO-dependent manner by acting on the injured vessels and mobilizing EPCs to the neo-endothelium.

Granulocyte Colony-Stimulating Factor–Mobilized Circulating c-Kit+/Flk-1+ Progenitor Cells Regenerate Endothelium and Inhibit Neointimal Hyperplasia After Vascular Injury

Background— Granulocyte colony-stimulating factor (G-CSF) treatment was shown to inhibit neointimal formation of balloon-injured vessels, whereas neither the identification of progenitor cells involved in G-CSF–mediated endothelial regeneration with a bone marrow (BM) transplant experiment nor the functional properties of regenerated endothelium have been studied.

Methods and Results— Recombinant human G-CSF (100 μg/kg per day) was injected daily for 14 days starting 3 days before balloon injury in the rat carotid artery. Neointimal formation of denuded vessels on day 14 was markedly attenuated by G-CSF (39% versus the control; P <0.05). Endothelial cell–specific immunostaining revealed an enhancement of re-endothelialization (1.8-fold increase versus the control; P <0.05) and inhibition of extravasation of Evans Blue dye (47%; P =0.02). The regenerated endothelium exhibited acetylcholine-mediated vasodilatation in NO-dependent manner. G-CSF increased the circulating c-Kit+/Flk-1+ cells (9.1-fold; P <0.02), which showed endothelial properties in vitro (acetylated low-density lipoprotein uptake and lectin binding) and incorporated into the regenerated endothelium in vivo. A BM replacement experiment with green fluorescent protein (GFP)–overexpressing cells showed that BM-derived GFP+/CD31+ endothelial cells occupied 39% of the total luminal length in the G-CSF–mediated neo-endothelium (2% in the control).

Conclusion— The G-CSF–induced mobilization of BM-derived c-Kit+/Flk-1+ cells contributes to endothelial regeneration, and this cytokine therapy may be a feasible strategy for the promotion of re-endothelialization after angioplasty.

Nicorandil regulates Bcl-2 family proteins and protects cardiac myocytes against hypoxia-induced apoptosis

Nicorandil has been shown to inhibit myocyte apoptosis by opening of mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels and nitrate-like effect against oxidative stress. However, the detailed mechanism of nicorandil-mediated cardioprotection under hypoxic conditions remains to be largely unknown. The present study examined whether nicorandil can inhibit apoptosis via regulation of Bcl-2 family proteins in hypoxic myocytes. Neonatal rat cardiac myocytes were exposed to hypoxia for 7 hours. Hypoxia-induced myocyte apoptosis (13.9+/-0.9%) under glucose-rich conditions. Myocyte apoptosis was accompanied by loss of mitochondrial membrane potential (Deltapsi(m)), cytochrome c release from mitochondria into cytosol, and activation of caspase-3. Hypoxia also significantly increased Bax and decreased Bcl-2 mRNA and protein expression, thereby increasing Bax/Bcl-2 ratio. Nicorandil 100 micromol/l significantly decreased the percentage of apoptotic myocytes (7.2+/-0.5%) by inhibiting loss of Deltapsi(m) and translocation of cytochrome c. These effects of nicorandil were partially but significantly inhibited by cotreatment of either 500 micromol/l 5-hydroxydecanoate, a selective mitoK(ATP) channel antagonist, or 10 micromol/l 1H-[1,2,4]oxidazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase. Moreover, nicorandil significantly inhibited the hypoxia-induced changes in Bax and Bcl-2 expression, and concomitant increased Bax and decreased Bcl-2 immunoreactivity in mitochondria. These effects of nicorandil in Bax and Bcl-2 expression were significantly blunted by cotreatment of ODQ and 5-HD, respectively. Cotreatment of KT5823, an inhibitor of protein kinase G, significantly blocked the effect of nicorandil on Bax expression and 8-bromo-cyclic guanosine 3',5' monophosphate (8-bromo-cGMP), a cGMP analog, mimicked the effect of nicorandil on Bax expression. The present study demonstrates that nicorandil regulates Bcl-2 family proteins via opening of mitoK(ATP) channels and nitric oxide-cGMP signaling and inhibits hypoxia-induced mitochondrial death pathway.

Histological analysis on adhesive molecules of renal intravascular large B cell lymphoma treated with CHOP chemotherapy and rituximab

A 48-year-old man was admitted to our hospital for investigation of mild renal dysfunction. A blood examination revealed mild elevation of creatinine level (1.77 mg/dl). Urinary examination revealed mild protein excretion (0.54 g/day) and microhematuria; renal biopsy revealed the focal proliferation of large mononuclear cells with mitosis in glomerular capillaries. According to immunohistochemical analysis, the intravascular lymphomatous cells stained positively with anti-leukocyte common antigen (LCA: CD45) and CD20, indicating a B lymphocyte lineage. In electron microscopy, the glomerular capillary was filled with lymphoma cells and epithelial foot process fusion was noted. Immunohistochemical analysis on adhesive molecules revealed a lack of CD11a expression on lymphoma cells, but positive CD54 expression on endothelial cells. Systemic 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) revealed no abnormal uptake of isotopes. On the basis of these findings, we diagnosed intravascular diffuse large B cell lymphoma localized in the kidney. Despite treatment with rituximab and CHOP (prednisolone, doxorubicin, vincristine, cyclophosphamide) for 3 cycles at 1-month intervals, the renal dysfunction did not change. In histopathological analysis of the second biopsy, lymphoma cells disappeared, but focal segmental glomerulosclerosis and moderate interstitial fibrosis were noted. Electron microscopic findings revealed severe subendothelial edema with mesangial interposition, indicating severe endothelial damage. Epithelial foot process fusion was improved. These pathological analyses let us conclude that a lack of CD11a could be a candidate factor for prevention of the extravasation of lymphoma cells from blood vessels in our patient. We also presumed that the intraglomerular endothelial damage occurred due to chemotherapy-associated cell injury.

Carbon dioxide-rich water bathing enhances collateral blood flow in ischemic hindlimb via mobilization of endothelial progenitor cells and activation of NO-cGMP system

BACKGROUND

Carbon dioxide-rich water bathing has the effect of vasodilatation, whereas it remains undetermined whether this therapy exerts an angiogenic action associated with new vessel formation.

METHODS AND RESULTS

Unilateral hindlimb ischemia was induced by resecting the femoral arteries of C57BL/J mice. Lower limbs were immersed in CO2-enriched water (CO2 concentration, 1000 to 1200 mg/L) or freshwater (control) at 37 degrees C for 10 minutes once a day. Laser Doppler imaging revealed increased blood perfusion in ischemic limbs of CO2 bathing (38% increase at day 28, P<0.001), whereas N(G)-nitro-L-arginine methyl ester treatment abolished this effect. Angiography or immunohistochemistry revealed that collateral vessel formation and capillary densities were increased (4.1-fold and 3.7-fold, P<0.001, respectively). Plasma vascular endothelial growth factor (VEGF) levels were elevated at day 14 (18%, P<0.05). VEGF mRNA levels, phosphorylation of NO synthase, and cGMP accumulation in the CO2-bathed hindlimb muscles were increased (2.7-fold, 2.4-fold, and 3.4-fold, respectively) but not in forelimb muscles. The number of circulating Lin-/Flk-1+/CD34- endothelial-lineage progenitor cells was markedly increased by CO2 bathing (24-fold at day 14, P<0.001). The Lin-/Flk-1+/CD34- cells express other endothelial antigens (endoglin and VE-cadherin) and incorporated acetylated LDL.

CONCLUSIONS

Our present study demonstrates that CO2 bathing of ischemic hindlimb causes the induction of local VEGF synthesis, resulting in an NO-dependent neocapillary formation associated with mobilization of endothelial progenitor cells.

Efficacy of biventricular pacing for dialysis-related hypotension due to idiopathic dilated cardiomyopathy

A 45-year-old man who had been undergoing maintenance hemodialysis for end-stage renal failure, caused by chronic glomerulonephritis 4 years before, was admitted to our hospital for biventricular pacemaker implantation (BVP). Ten years ago, he was diagnosed with idiopathic dilated cardiomyopathy, and had been suffering from dialysis-related hypotension (DRH) due to low cardiac function over the past year. An electrocardiogram revealed complete left bundle branch block with a QRS duration of 180 ms, and echocardiography showed moderate hypokinesis of the left ventricular wall and systolic asynchronized motion of the septum and free wall. After BVP, the left ventricular ejection fraction had increased from 29% to 40%, and the transmitral rapid left ventricular filling (E wave) and atrial contraction (A wave) ratio (E/A) had improved from 1.3 to 1.0. Before and after BVP, we measured hemodynamic parameters during hemodialysis by successive echocardiography. Before BVP, systemic vascular resistance had decreased, cardiac output had not changed, and hypotension was noted. In contrast, after BVP, cardiac output had increased and systemic vascular resistance had not changed, which caused an increase in blood pressure. We conclude that BVP improved the cardiac function which resulted in an improvement in dialysis-related hypotension (DRH).

Targeted delivery of bone marrow mononuclear cells by ultrasound destruction of microbubbles induces both angiogenesis and arteriogenesis response

OBJECTIVE

Ultrasound (US)-mediated destruction of contrast microbubbles causes capillary rupturing that stimulates arteriogenesis, whereas intramuscular implantation (im) of bone marrow mononuclear cells (BM-MNCs) induces angiogenesis. We therefore studied whether US-targeted microbubble destruction combined with transplantation of BM-MNCs can enhance blood flow restoration by stimulating both angiogenesis and arteriogenesis.

METHODS AND RESULTS

US-mediated destruction of phospholipid-coated microbubbles was applied onto ischemic hindlimb muscle and subsequently BM-MNCs were transfused. A significant enhancement in blood flow recovery after Bubble+US+BM-MNC infusion (34% increase, P<0.05) was observed compared with Bubble+US (25%). The ratio of capillary/muscle fiber increased by Bubble+US+BM-MNC-i.v (260%, P<0.01) than that in the Bubble+US group (172%), into which BM-MNCs were incorporated (angiogenesis). Smooth muscle alpha-actin-positive arterioles were also increased, and angiography showed augmented collateral vessel formation (arteriogenesis). Platelet-derived proinflammatory factors activated by Bubble+US induces the expression of adhesion molecules (P-selectin and ICAM-1), leading to the attachment of transplanted BM-MNCs on the endothelium. Flow assay confirmed that the platelet-derived factors cause the adhesion of BM-MNCs onto endothelium under laminar flow.

CONCLUSIONS

This study demonstrates that the targeted delivery of BM-MNCs by US destruction of microbubbles enhances regional angiogenesis and arteriogenesis response, in which the release of platelet-derived proinflammatory factors activated by Bubble+US play a key role in the attachment of transplanted BM-MNCs onto the endothelial layer.

Macrophage Colony-Stimulating Factor (M-CSF), As Well As Granulocyte Colony-Stimulating Factor (G-CSF), Accelerates Neovascularization

It has been reported that bone marrow cells (BMCs) differentiate into endothelial cells of blood vessels, and that granulocyte colony-stimulating factor (G-CSF) mobilizes progenitors in the BMCs to the peripheral blood, while macrophage colony-stimulating factor (M-CSF) augments the production of monocytes. We examined whether M-CSF augments the differentiation of BMCs into endothelial cells of blood vessels using a hindlimb-ischemic model. Either G-CSF or M-CSF, or both, was administered to the hindlimb-ischemic mice for 3 days. Both M-CSF and G-CSF augmented the differentiation of BMCs into endothelial cells of blood vessels through vascular endothelial cell growth factor (VEGF), resulting in early recovery of blood flow in the ischemic limbs.

Mobilization of bone marrow cells by G-CSF rescues mice from cisplatin-induced renal failure, and M-CSF enhances the effects of G-CSF

Cisplatin, which is a broadly used anticancer drug, is widely known to induce acute renal failure as a result of renal tubular injury. This article examines whether G-CSF and/or M-CSF rescues mice from renal failure induced by cisplatin. BALB/c mice received intraperitoneal injections with or without G-CSF and/or M-CSF for 5 d (from day -5 to day -1). The day after the last injection of G-CSF and/or M-CSF (day 0), the mice received an intraperitoneal injection of cisplatin. When pretreated with G-CSF or G-CSF + M-CSF, the mice showed longer survival and lower serum creatinine and blood urea nitrogen levels than mice that had been received injections of M-CSF or saline. Histologically, pretreatment with G-CSF or G-CSF + M-CSF attenuated the damage to renal tubules induced by cisplatin. BALB/c mice that had received a transplant of bone marrow cells of enhanced green fluorescent protein (EGFP)-transgenic mice ([EGFP-->BALB/c] mice) were treated with or without G-CSF and/or M-CSF, followed by injection of cisplatin as well as above. [EGFP-->BALB/c] mice that were treated with G-CSF or G-CSF + M-CSF showed a significantly higher number of EGFP(+) tubular epithelial cells in the kidney than mice that were treated with only M-CSF or saline. These results suggest that bone marrow cells mobilized by G-CSF accelerate the improvement in renal functions and prevent the renal tubular injury induced by cisplatin and that M-CSF enhances the effects of G-CSF.

Augmentation of Pulse Wave Velocity Precedes Vascular Structural Changes of the Aorta in Rats Treated with N.OMEGA.-Nitro-L-Arginine Methyl Ester

We examined the relationship between structural changes of the aorta and pulse wave velocity (PWV), and the effects of antihypertensive treatments on PWV in N(omega)-nitro-L-arginine methyl ester (L-NAME)-treated rats. Twelve-week-old Wistar-Kyoto (WKY) rats were divided into the following groups, all of which received drug treatment in their drinking water: an untreated control group (n = 36), an L-NAME-treated group (0.7 mg/ml) (n = 32), an L-NAME and angiotensin converting enzyme (ACE) inhibitor (ACEI)-treated group (imidapril: 0.4 mg/ml) (n = 8), and an L-NAME and hydralazine-treated group (0.2 mg/ml) (n = 10). PWV was measured at the same blood pressure (BP) level as in the control group and the wall-to-lumen ratio of the thoracic aorta was evaluated in all groups. In the L-NAME group, PWV increased compared with the value in the control group, at the same time that BP was increasing. After the third day of treatment, PWV was higher in the L-NAME group than in the control group after adjusting BP to the control level, while the wall-to-lumen ratios were equal between the two groups. After the first week of treatment, not only the adjusted PWV, but also the wall-to-lumen ratios were greater in the L-NAME group than in the control group. With administration of antihypertensive agents, both PWV and the thickening of the aortic wall were reduced, but there was no significant difference between the ACEI and hydralazine-treated groups. In conclusion, in a rat model of nitric oxide (NO) synthesis inhibition, the increase in PWV preceded the vascular structural changes, while antihypertensive treatment reduced both changes. There was no significant difference between treatments with ACEI and hydralazine in this model.

Mechanism for IL-1 beta-mediated neovascularization unmasked by IL-1 beta knock-out mice

We have reported that interleukin-1 beta (IL-1 beta) upregulates cardiac expression of vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2), raising the possibility that IL-1 beta plays an important role in VEGF-mediated neovascularization. In this study, we examined the cellular mechanism for ischemia-induced neovascularization using IL-1 beta knock-out (-/-) mice. Recovery of blood perfusion in ischemic hindlimb in IL-1 beta-/- mice was markedly (43% decrease) impaired as compared with the wild-type mice. CD31(+) vessel numbers and Ki-67(+) neo-capillaries were significantly (P < 0.01) decreased 44% and 68%, respectively. IL-1 beta expression was localized in the capillary vessels in ischemic limb muscles. Ischemia-induced expressions of hypoxia-inducible factor 1 alpha (HIF-1 alpha), VEGF, its receptor VEGFR-2 and vascular cell adhesion molecule-1 (VCAM-1) were markedly inhibited in the IL-1 beta-/- mice. Hindlimb ischemia-induced an increase (1.22% out of total nuclear cell) in CD34(-)/B220(-)/CD3(-)/Flk-1(+) hematopoietic stem cell population in peripheral blood in the wild-type mice, whereas in the IL-1 beta-/- mice such increase was only 0.09%. Injection of IL-1 beta protein into the wild-type mice markedly increased the ratio of the CD34(-)/B220(-)/CD3(-)/Flk-1(+) cell population (from 0.03% to 0.7%) in the peripheral blood associated with an increase in the number of endothelial cells. Such IL-1 beta-mediated increases in cell numbers were blocked by co-injection of anti-VEGF antibody. CD34(-)/B220(-)CD3(-)Flk-1(+) cells trans-differentiated into eNOS- and CD31-expressing endothelial cells in vivo and in vitro. This study demonstrates that IL-1 beta plays a key role in ischemia-induced neovascularization by mobilizing CD34(-)/B220(-)CD3(-)Flk-1(+) endothelial precursor cells in a VEGF-dependent manner as well as by upregulating expressions of VEGF, VEGFR-2 and adhesion molecules on endothelial cells.