Efficacy of prophylactic antibiotics for the prevention of neutropenic fever in patients with multiple myeloma receiving high-dose cyclophosphamide for stem cell mobilization

High-dose cyclophosphamide (HD-Cy) (3 g/m2) plus granulocyte colony-stimulating factor (G-CSF) is a very effective regimen for peripheral blood stem cell (PBSC) mobilization. Unfortunately, it is associated with an increased risk of neutropenic fever (NF). We analyzed the effect of NF on PBSC apheresis results and the efficacy of prophylactic antibiotics for the prevention of NF associated with HD-Cy plus G-CSF for PBSC mobilization in patients with newly diagnosed multiple myeloma (MM). First, patients were divided into NF ( +) and NF ( -) groups according to whether they suffered from NF during mobilization. Second, we divided patients into an antibiotic prophylaxis group and a nonantibiotic prophylaxis group according to whether antibiotic prophylaxis was used during the mobilization period. Our study showed that NF( +) patients (n = 44) had lower CD34 + cell dose collection (median 2.60 versus 5.34 × 106/kg, P < 0.001) and slower neutrophil engraftment and platelet engraftment (median 11 versus 10 days, P = 0.002, and median 13 versus 11 days, P = 0.043, respectively) than NF( -) patients (n = 234). Of note, the nonantibiotic prophylaxis group patients (n = 30) had a 26.7% incidence of NF. In the patients receiving antibiotic prophylaxis (n = 227), the incidence was reduced to 9.3% (P = 0.01). The antibiotic prophylaxis patients had higher CD34 + cell collection (median 5.41 versus 2.27 × 106/kg, P < 0.001) and lower hospitalization cost of mobilization ($ median 3108.02 versus 3702.39, p = 0.012). Thus, our results demonstrate that NF is associated with lower CD34 + cell collection and that antibiotic prophylaxis can reduce the incidence of NF and improve stem cell mobilization and collection outcomes, which reduces the hospitalization cost of mobilization.

[Investigation of the immune profile of multiple myeloma patients achieving long-term survival after autologous stem cell transplantation]

Objective: To identify the characteristics of the bone marrow immune microenvironment associated with long-term survival in multiple myeloma (MM) patients. Methods: In the follow-up cohort of patients with newly diagnosed MM and who received "novel agent induction therapy and subsequent autologous stem cell transplantation and immunomodulator maintenance therapy" in the First Affiliated Hospital of Sun Yat-sen University, a cross-sectional study was carried out between August 2019 and May 2020. Using NanoString technology, the RNA expression of 770 bone marrow immune-related markers was compared between 16 patients who had progression-free survival ≥5 years and 5 patients with progressive disease. Among the 16 patients who achieved long-term survival, 9 achieved persistent minimal residual disease (MRD) negative while the other 7 had persistent positive MRD. The functional scores of each kind of immune cells were calculated based on the expression level of characteristic genes, so as to indirectly obtained the proportion of each immune cell subset. The Mann-Whitney U test and the Kruskal Wallis test were used for statistical analysis. Results: The proportion of neutrophils was significantly higher in long-surviving MM patients than in patients with progressive disease [functional scores, 13.61 (13.33, 14.25) vs. 12.93 (12.58, 13.38); Z=2.31, P=0.021]. Among long-surviving patients, those who were MRD-positive had a significantly greater number of mast cells compared with those who were MRD-negative [functional scores, 7.09 (6.49, 8.57) vs. 6.03 (5.18, 6.69); H=2.18, P=0.029]. Compared with patients with progressive disease, four genes (CTSG, IFIT2, S100B, and CHIT1) were significantly downregulated and six (C4B, TNFRSF17, CD70, IRF4, C2, and GAGE1) were upregulated in long-surviving patients. Among long-surviving patients, only gene CMA1 was significantly upgraded, 10 genes (ISG15, OAS3, MX1, IFIT2, DDX58, SIGLEC1, CXCL10, IL1RN, SERPING and TNFSF10) were significantly downregulated in the MRD-positive group compared with that in the MRD-negative group, the first 5 of which are related to the interferon response pathway. Conclusions: The increased neutrophil and mast cell numbers may be related to long-term survival in MM. Interferon signaling activation may be a key bone marrow immune profiling feature for MRD-negative, long-surviving patients with MM.

On-demand plerixafor added to high-dose cyclophosphamide and pegylated recombinant human granulocyte colony-stimulating factor in the mobilization of patients with multiple myeloma: a treatment with high effectiveness, convenient, and affordable cost

Objective

The combination of high-dose cyclophosphamide (HD-Cy) (3g/m2) plus granulocyte colony-stimulating factor (G-CSF) and on-demand plerixafor (PXF) has been considered an effective mobilization regimen of patients with multiple myeloma(MM). However, the daily multi-injection regimen of G-CSF poses challenges. This study delves into the efficiency and cost implications of a novel approach, using HD-Cy alongside pegylated G-CSF (PEG G-CSF) and on-demand PXF. Unlike G-CSF, which necessitates daily injections, the half-life of PEG G-CSF extended allows for a single injection.

Methods

A retrospective analysis was conducted on 350 MM patients, which were categorized based on their mobilization regimens: Cy+PEG G-CSF+/-PXF (n=66), Cy+PEG G-CSF (n=91), Cy+ G-CSF (n=169), and G-CSF+PXF (n=24).

Results

Mobilization with Cy+PEG G-CSF+/-PXF(8.79)yielded a notably higher median CD34+ cell count compared to the other regimens: Cy+PEG G-CSF(4.96), Cy+G-CSF (4.65), and G-CSF+PXF (2.99) (P<0.001). The percentage of patients who achieved >6×106/kg CD34+ cells was significantly higher in the Cy+PEG G-CSF+/-PXF group (77.3%) than in the other mobilization regimens: Cy+PEG G-CSF (41.8%), Cy+ G-CSF (37.3%), and G-CSF+PXF (8.3%) (P<0.001). From a cost perspective, the Cy+PEG G-CSF+/-PXF approach was more economical than the G-CSF+PXF strategy but was marginally costlier than the other two methods. A multivariate assessment highlighted that the combination of Cy+PEG G-CSF with on-demand PXF had a superior potential to achieve the desired harvest (6×106/kg) compared to the Cy+PEG G-CSF protocol without PXF. The incremental cost-effectiveness ratio for each 1% increase in the probability of achieving a successful optimal harvest was $ 97.02 per patient. The incidence of neutropenic fever was 3.0% in the Cy+PEG G-CSF+/-PXF group.

Conclusion

The combination of on-demand PXF with HD-Cy and PEG G-CSF offers a cost-effective approach with a high mobilization success rate, manageable side effects, and the convenience of fewer injections. It stands as a promising mobilization strategy for MM patients.

[New agents-based induction chemotherapy followed by autologous stem cell transplantation and maintenance treatment strategy for multiple myeloma: a single center retrospective study of 300 cases]

Objective: To examine the survival and influential factors of an integrated approach of novel agents, autologous hematopoietic stem cell (auto-HSCT) , and maintenance therapy in patients with multiple myeloma (MM) patients from a single center over the past 15 years. Methods: In our center, 300 MM patients who received an integrated strategy of new agents, auto-HSCT, and maintenance therapy over 15 years were retrospectively and prospectively analyzed. Results: The complete remission rates (CR) and ≥very good partial remission rates (VGPR) following induction therapy, transplantation, and maintenance therapy were respectively 35.3% and 55.2% , 72.4% and 80.0% , 89.2% , and 93.4% . When compared to patients receiving double-drug induction, the ≥VGPR and ORR of patients receiving triple-drug induction were improved. No difference existed in CR, ≥VGPR, and ORR between the PAD (bortezomib + liposome doxorubicin+ dexamethasone) and RAD (lenalidomide + liposome doxorubicin + dexamethasone) regimens, but the benefits speed differed. The negative rate of flow minimal residual disease following induction, transplantation, and maintenance was 18.8% (54 cases) , 41.4% (109 cases) , and 58.7% (142 cases) , respectively. The median time to progress (TTP) was 78.7 months and the median overall survival (OS) was 109 months. The median TTP for RISS-Ⅰ-Ⅲ patients were 111.8 months, 77.4 months, and 30.6 months, and the median OS was 118.8 months, 91.4 months, and 48.5 months, respectively. At various points during treatment, the TTP and OS of patients obtaining CR and MRD negative were longer than those of patients who did not obtain CR and MRD negative. TTP was noticeably shorter in high-risk cytogenetic patients compared to standard-risk patients even when CR was acquired during induction. There was no difference in TTP between patients with high-risk cytogenetics and those with standard-risk cytogenetics if MRD negative was acquired during induction. According to a multivariate analysis, the R-ISS stage was a poor predictor of TTP and OS at various treatment intervals. Therapeutic effectiveness was a newly independent prognostic factor following treatment. Conclusion: A median survival of almost 10 years is possible for MM patients who receive an integrated strategy of induction regimens followed by auto-HSCT and maintenance therapy, which significantly improves prognosis. However, this approach did not significantly benefit high-risk cytogenetic MM patients.

[High dose melphalan (HDM) is superior to cyclophosphamide plus etoposide and busulfan (CVB) as the conditioning regimen in autologous stem cell transplantation for multiple myeloma]

目的

比较大剂量美法仑（HDM）和环磷酰胺、依托泊苷联合白消安（CVB）预处理方案应用于新诊断多发性骨髓瘤（NDMM）患者自体造血干细胞移植（ASCT）的安全性、近期及远期疗效。

方法

回顾性分析2011年1月至2017年8月期间接受PAD（硼替佐米+脂质体阿霉素+地塞米松）方案诱导治疗序贯ASCT的NDMM患者共123例，按接受预处理方案分为CVB组（82例）和HDM组（41例）。

结果

①非血液学不良反应方面两者无显著区别。②CVB组中性粒细胞植入和血小板植入较HDM组快，中性粒细胞植入时间为第10（9~35）天对第11（9~12）天（z=−3.433，P=0.001）；血小板植入时间为11（7~55）d对HDM组13（10~35）d（z=−3.506，P<0.001）；但CVB组也更早进入粒细胞缺乏（粒缺）及显著血小板减少，最终粒缺及显著血小板减少持续时间两组间尚未显示出差别；但CVB组的发热持续时间以及相应抗生素使用时间显著延长。③CVB组经过移植后获得传统疗效进步的患者比例显著低于HDM组（9/46对14/28，P=0.021）；而且移植后3个月CVB组的微小残留病（MRD）阴性率有低于HDM组的趋势（31.7%对48.8%，P=0.065）。④无论单因素还是多因素分析均显示两种预处理方案并不影响接受PAD诱导序贯ASCT及维持治疗的NDMM患者的至进展时间（TTP）（P= 0.619）及总生存（OS）时间（P=0.295）。

结论

HDM预处理方案血液学不良反应、减低MM肿瘤负荷以及使用方便性方面较CVB方案具有优势，但采用两种预处理方案的ASCT治疗MM的TTP和OS未见明显差异。

[Bortezomib-based induction chemotherapy followed by autologous hematopoietic stem cell transplantation and maintenance in 200 patients with multiple myeloma: long-term follow-up results from single center]

Objective: To study the efficacy, safety and long-term outcomes of integrated strategy of bortezomib-based induction regimens followed by autologous hematopoietic stem cell (ASCT) and maintenance therapy in Chinese multiple myeloma (MM) patients. Methods: 200 MM patients receiving integrated strategy of bortezomib--based induction regimens followed by ASCT and maintenance therapy were retrospectively and prospectively analyzed from December 1. 2006 to April 30. 2018. Results: The complete remission rates (CR) and better than very good partial remission rates (VGPR) after induction therapy, transplantation and maintenance therapy were respectively 31% and 75.5%, 51.8% and 87.7%,73.6% and 93.4%. There was no difference between 4 cycles and more than 5 cycles induction chemotherapy. The negative rate of MRD detection by flow cytometry was 17.6% and 38.2% respectively after induction and 3 months after transplantation. The negative rate of MRD gradually increased during the maintenance therapy. The success rate of high dose CTX combined with G-CSF mobilization was 95.5% and transplantation related mortality (TRM) was zero. The median time to progress (TTP) was 75.3 months and the median overall survival (OS) was 99.5 months. TTP of patients obtaining CR and negative MRD after induction were longer that those of no CR and positive MRD. TTP and OS of patients receiving triple-drug induction and ASCT in early stage were longer than those of double-drug induction and ASCT in late stage. LDH≥240 U/L, high risk cytogenetics, ISS II+III stage and HBsAg positive were prognostic factors at diagnosis. However, only MRD and high risk cytogenetics were independent prognostic factors after transplantation and maintenance therapy. The clinical characteristics of patients of TTP ≥6 years were listed below: light-chain type M protein, ISS I stage, normal level of hemoglobin and platelet, normal LDH, HBsAg negative, chromosome 17p-negative, good response and sustained good response. Conclusions: Integrated strategy of bortezomib-based induction regimens followed by ASCT and maintenance therapy can significantly improve the short-term and long-term efficacy. The prognostic factors of TTP in different disease stages were different. Response to treatment, especially MRD, played a more important role in prognostic factors.

The acute toxic effects of platinum nanoparticles on ion channels, transmembrane potentials of cardiomyocytes in vitro and heart rhythm in vivo in mice

Background

Platinum nanoparticles (PtNPs) have been considered a nontoxic nanomaterial and been clinically used in cancer chemotherapy. PtNPs can also be vehicle exhausts and environmental pollutants. These situations increase the possibility of human exposure to PtNPs. However, the potential biotoxicities of PtNPs including that on cardiac electrophysiology have been poorly understood.

Methods

Ion channel currents of cardiomyocytes were recorded by patch clamp. Heart rhythm was monitored by electrocardiogram recording. Morphology and characteristics of PtNPs were examined by transmission electron microscopy, dynamic light scattering and electrophoretic light scattering analyses.

Results

In cultured neonatal mice ventricular cardiomyocytes, PtNPs with diameters 5 nm (PtNP-5) and 70 nm (PtNP-70) concentration-dependently (10^–9 – 10^–5 g/mL) depolarized the resting potentials, suppressed the depolarization of action potentials and delayed the repolarization of action potentials. At the ion channel level, PtNPs decreased the current densities of I_Na, I_K1 and I_to channels, but did not affect the channel activity kinetics. In vivo, PtNP-5 and PtNP-70 dose-dependently (3–10 mg/kg, i.v.) decreased the heart rate and induced complete atrioventricular conduction block (AVB) at higher doses. Both PtNP-5 and PtNP-70 (10^–9 – 10^–5 g/mL) did not significantly increase the generation of ROS and leak of lactate dehydrogenase (LDH) from cardiomyocytes within 5 mins after exposure except that only very high PtNP-5 (10^–5 g/mL) slightly increased LDH leak. The internalization of PtNP-5 and PtNP-70 did not occur within 5 mins but occurred 1 hr after exposure.

Conclusion

PtNP-5 and PtNP-70 have similar acute toxic effects on cardiac electrophysiology and can induce threatening cardiac conduction block. These acute electrophysiological toxicities of PtNPs are most likely caused by a nanoscale interference of PtNPs on ion channels at the extracellular side, rather than by oxidative damage or other slower biological processes.

[The role and mechanism of regulatory T cells in indirect acute lung injury]

Objective: To study the role and mechanism of CD(4)(+) CD(25)(+) FoxP3(+) regulatory T cells (Tregs) in the pathophysiological process of indirect acute lung injury (iALI) in mice. Methods: The iALI model was successfully induced by shock/cecal ligation and puncture method. Sham (n=8), cecal ligation and puncture (CLP, n=10), and hemorrhage (Hem, n=12) groups were established as controls. Two experimental groups were established: CLP+Hem (n=15) without Tregs adoptive transfer (AT), and CLP+Hem with Tregs adoptive transfer (CLP+Hem+AT, n=14). The number of Tregs, subsets of lymphocytes, neutrophil activity, apoptosis, cytokine levels and histopathological changes were measured in the lung tissue of each group. The protein exudation and the expression of IL-10 in bronchoalveolar lavage fluid (BALF) were also detected. After in vitro cell co-culture, the proliferation of activated T cells and the expression of IL-10, INF-γ and iNOS protein were detected. Results: The percentage and the absolute cell number of CD(4)(+) CD(25)(+) FoxP3(+) Tregs in lung tissue of iALI mice were (2.530±0.086)%, and (1.441±0.090)×10(4)/ml, respectively, which were significantly higher than the control groups (P<0.05). Adoptive transfer of Tregs could significantly decrease CD3-positive T lymphocytes, myeloperoxidase (MPO) activity, caspase-3 activity in lung tissue as well as protein leakage in BALF (P<0.05). Meanwhile interleukin-10 (IL-10) levels in lung tissue and BALF were up-regulated from (121.4±43.76) pg/ml to (201.0±61.96) pg/ml (t=2.776, P<0.05) and (206.2±90.88) pg/ml to (339.4±109.5) pg/ml (t=2.477, P<0.05), respectively. Histopathology was also significantly improved. The proliferation of activated T lymphocytes in the adoptive transfer Treg (AT-Treg) group (n=5) was significantly lower than that in the natural regulatory T cell (N-Treg) group (n=5, t=7.485, P<0.01) and the negative control group (n=5, t=16.66, P<0.01). However, iNOS enzyme inhibitor L-NMMA could significantly reduce the T cell proliferation (P<0.05). Conclusion: CD(4)(+)CD(25)(+)FoxP3(+) Tregs could reduce inflammatory reaction in mice with iALI, and the iNOS signaling pathway may be involved in this process.

The acute toxic effects of silver nanoparticles on myocardial transmembrane potential, INa and IK1 channels and heart rhythm in mice

This study focused on the potential toxicity of silver nanoparticles (AgNPs) on cardiac electrophysiology which is rarely investigated. We found that AgNPs (10^-9-10^-6g/ml) concentration-dependently depolarized the resting potential, diminished the action potential, and finally led to loss of excitability in mice cardiac papillary muscle cells in vitro. In cultured neonatal mice cardiomyocytes, AgNPs (10^-9-10^-7g/ml) concentration-dependently decreased the Na⁺ currents (I_Na), accelerated the activation, and delayed the inactivation and recovery of Na⁺ channels from inactivation within 5 min. AgNPs at 10^-8g/ml also rapidly decreased the inwardly rectifying K⁺ currents (I_K1) and delayed the activation of I_K1 channels. Intravenous injection of AgNPs at 3 mg/kg only decreased the heart rate, while at ≥4 mg/kg sequentially induced sinus bradycardia, complete atrio-ventricular conduction block, and cardiac asystole. AgNPs at 10^-10-10^-6g/ml did not increase reactive oxygen species (ROS) generation and only at 10^-6g/ml mildly induced lactate dehydrogenase (LDH) release in the cardiomyocytes within 5 min. Endocytosis of AgNPs by cardiomyocytes was not observed within 5 min, but was observed 1 h after exposing to AgNPs. Comparative Ag⁺ (≤0.02% of the AgNPs) could not induce above toxicities. We conclude that AgNPs exert rapid toxic effects on myocardial electrophysiology and induce lethal bradyarrhythmias. These acute toxicities are likely due to direct effects of AgNPs on ion channels at the nano-scale level, but not caused by Ag⁺, ROS, and membrane injury. These findings provide warning to the nanomedical practice using AgNPs.

[Epidemiology of febrile neutropenia in patients with hematological disease-a prospective multicentre survey in China]

目的

了解中国血液病患者中性粒细胞缺乏（粒缺）伴发热的发生率、临床和微生物学特征及危险因素。

方法

前瞻性研究2014年10月20日至2015年3月20日来自全国11家血液病中心发生粒缺伴发热的连续血液病患者发热情况及危险性因素。

结果

1 139例患者共发生784例次粒缺伴发热，粒缺持续21 d时发热的累积发生率为81.9%。多因素分析显示中心静脉置管（P<0.001，HR= 3.407，95% CI 2.276~4.496）、胃肠道黏膜炎（P<0.001，HR=10.548, 95% CI 3.245~28.576）、既往90 d内暴露于广谱抗生素（P<0.001，HR=3.582，95% CI 2.387~5.770）和粒缺持续时间>7 d（P<0.001，HR= 4.194，95% CI 2.572~5.618）是粒缺伴发热的危险因素。无任何危险因素、具备1项、2项、3~4项危险因素患者发热的累计发生率依次增加（35.4%、69.2%、86.1%及95.6%，P<0.001）。784例次粒缺伴发热中，不明原因发热253例次（32.3%），临床证实的感染429例次（54.7%），微生物学证实的感染102例次（13.0%）。最常见的感染部位依次为肺（388例次，49.5%）、上呼吸道（159例次，16.0%）、肛周组织（77例次，9.8%）、血流（60例次，7.7%）。最常见的病原菌为革兰阴性菌（44.54%），其次为革兰阳性菌（37.99%）和真菌（17.47%）。发热与未发热患者相比，两组之间总体病死率差异无统计学意义（9.2%对4.8%，P=0.099）。多因素分析显示年龄>40岁（P=0.047，HR=5.000，95% CI 0.853~28.013）、血流动力学不稳（P=0.001，HR=13.185, 95% CI 2.983~54.915）、既往耐药菌的定植或感染（P=0.005，HR=28.734，95% CI 2.921~313.744）、血流感染（P=0.038，HR=9.715, 95% CI 1.110~81.969）和肺部感染（P=0.031，HR=25.905, 95% CI 1.381~507.006）是与总体死亡相关的危险因素。

结论

发热是血液病患者粒缺期常见的合并症，不同部位的感染有不同的致病菌谱。粒缺持续时间>7 d、中心静脉置管、胃肠道黏膜炎和既往90 d内暴露于广谱抗生素是粒缺伴发热发生的危险因素。

Kv1.3 channel blockade enhances the phagocytic function of RAW264.7 macrophages

This study aimed to comprehend the largely unknown role of voltage-gated potassium channel 1.3 (Kv1.3) in the phagocytic function of macrophages. We found that blocking of the Kv1.3 channel with 100 pmol L(-1) Stichodactyla helianthus neurotoxin (ShK) enhanced the phagocytic capacities of both resting and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in the chicken erythrocyte system. In the fluorescein isothiocyanate (FITC)-labeled Escherichia coli k-12 system, ShK increased the phagocytic capacities of resting RAW264.7 cells, but not of the LPS-stimulated cells, as LPS alone stimulated almost saturated phagocytosis of the macrophages. ShK increased the nitric oxide (NO) production in LPS-activated cells, but not in resting RAW264.7 cells. There was no effect of ShK alone on the cytokine secretions in resting RAW264.7 cells, but it suppressed IL-1β secretion in LPS-stimulated RAW264.7 cells. At a concentration of 100 pmol L(-1), ShK did not affect the viability of the tested cells. Kv1.3 was expressed in RAW264.7 cells; this expression was downregulated by LPS, but significantly upregulated by disrupting caveolin-dependent endocytosis with filipin III. In addition, cytochalasin D, an inhibitor of actin polymerization, did not affect the Kv1.3 expression. Thus, blocking of the Kv1.3 channel enhances the phagocytic capacity and NO production of this cell line. Our results suggest that Kv1.3 channel serves as a negative regulator of phagocytosis in macrophages and can therefore be a potential target in the treatment of macrophage dysfunction.

Donor factors predictive for poor outcomes of living donor kidney transplantation

INTRODUCTION

The aim of this study was to explore donor risk factors that predict the poor outcomes after living donor kidney transplantation.

METHODS

We retrospectively analyzed our 219 living donor kidney transplantations collecting donor age and gender, graft glomeular filtration rate (GFR), human leukocyte antigen (HLA) typing, recipient age and gender, acute rejection episodes chronic rejection, and 1-year serum creatinine level. Patient and graft survivals were calculated using the Kaplan-Meier analysis. Independent donor risk factors affecting graft survival and 1-year serum creatinine level were analyzed using Cox regression and logistic regression.

RESULTS

One-, 3-, 5-year patient and graft survivals were 98.6%, 98.1%, and 97.4% and 97.7%, 95.0%, and 92.2%, respectively. Acute rejection rate was 12.8%, and chronic rejection, 4.1%. If donor age was over 50 years, there were significantly increased incidences of acute and chronic rejection (χ(2) were 5.385 and 5.039; P < .05). Univariate analysis showed donor age > 50 years, graft GFR < 35 mL/min, female to male, HLA mismatch > 3 loci to be risk factors for an abnormal 1-year serum creatinine. Logistic multivariate regression revealed donor age > 50 years, female to male, and graft GFR before transplant < 35 mL/min to be independent risk factors for an abnormal 1-year serum creatinine level (odds ratio values 5.928, 2.489, and 6.993, respectively; P < .05). Cox multivariate regression demonstrated that graft GFR before transplant < 35 mL/min was an independent risk factor for long-term graft survival (relative risk value = 6.984; P = .004).

CONCLUSION

Older donor, female to male, and insufficient graft GFR before transplantation are predictive factors for poor outcomes of living donor kidney transplantations.

[In vitro study of human multiple myeloma cell transfected with soluble vascular endothelial growth factor receptor-1 gene]

BACKGROUND AND OBJECTIVE

Vascular endothelial growth factor (VEGF) is the most important angiogenic factor of multiple myeloma (MM). This study was to investigate the effect of transfection of human soluble vascular endothelial growth factor receptor-1 (sFlt-1) gene on the proliferation of human MM cell line RPMI8226.

METHODS

The recombinant plasmid pcDNA3-sFlt-1 was constructed and transfected into RPMI8226 cells. The expression of sFlt-1 was identified by reverse transcription-polymerase chain reaction (RT-PCR) and ELISA. The effects of sFlt-1 protein on the proliferation and VEGF expression of RPMI8226 cells were investigated by MTT assay and ELISA, respectively.

RESULTS

The recombinant plasmid pcDNA3-sFlt-1 was successfully transfected into RPMI8226 cells. sFlt-1 protein expression was identified by ELISA, which inhibited the proliferation of RPMI8226 cells and reduced VEGF concentration in the culture supernatant.

CONCLUSION

RPMI8226 cells can express sFlt-1 protein with high biological activity when transfected with the sFlt-1 gene, which inhibits the proliferation of RPMI8226 cells.

[The clinical features and risk factors for invasive fungal infection in multiple myeloma.]

OBJECTIVE

To study the clinical features and risk factors of invasive fungal infection (IFI) in multiple myeloma (MM).

METHODS

Three hundred and fifty-seven cases of MM were retrospectively analyzed for IFI, clinical features, complicating diseases, treatment of fungus and side effect of anti-fungal drugs.

RESULTS

Forty-four cases (12.3%) of IFI were diagnosed. Three of them were diagnosed definitely, 8 clinically and 33 probably. Ten cases incurred IFI in the induction therapy, 4 in platform, 27 in progress and 3 in the treatment with autologous stem cell transplantation. The lung was the commonest site of infection (50.0%). The total effective rates of amphotericin B liposome, voriconazole, itraconazole, caspofungin and fluconazol were 83.3%, 75.0%, 78.9%, 75.0% and 57.1% respectively (P = 0.493). In a multivariate analysis, independent factors significantly associated with IFI were diabetes (P = 0.035, OR 2.527, 95%CI 1.005 - 6.052), dialysis (P = 0.022, OR 2.768, 95%CI 1.161 - 6.600), persistent agranulocytosis (P = 0.019, OR 3.215, 95%CI 1.200 - 7.407), broad-spectrum antibiotic therapy (P = 0.009, OR 3.350, 95%CI 1.353 - 8.295) and fludarabine treatment (P = 0.001, OR 4.669, 95%CI 1.813 - 12.023).

CONCLUSIONS

Patients with MM are in high risk of IFI. The lung is the commonest site of infection. The therapeutic effect was similar with itraconazole, voriconazole, caspofungin and amphotericin B liposome in MM patients with complicating IFI. The risk factors for IFI in MM were diabetes, dialysis, persistent agranulocytosis and the use of broad-spectrum antibiotics and fludarabine.

[The clinical features, chemotherapy responses and survival of 223 patients with newly diagnosed multiple myeloma]

OBJECTIVE

To explore the proportion, clinical and laboratory features, chemotherapy responses and long term survival of different kinds of newly diagnosed multiple myeloma (MM) in China.

METHODS

The clinical data of 223 cases of newly diagnosed MM patients were gathered in the First Affiliated Hospital of Sun Yat-sen University from Jan, 2000 to Seb, 2007 were retrospectively analyzed.

RESULTS

The proportions of each kind of MM including IgG, IgA, light chain, IgD, IgM and biclonal MM were 48.0%, 20.6%, 25.6%, 4.0%, 0.9% and 0.9% respectively. No IgE and nonsecretory myeloma was found. The median age of onset was 58 years, of which that of the IgA type was the oldest one and the light chain type was the youngest (P = 0.004). Bone pain, renal insufficiency, and anemia were the most common symptoms which accounted for 67.7%, 61.0% and 45.3% respectively. The incidences of renal inadequacy, hypercalcemia and pathological fracture in light chain type were higher than those in IgG and IgA types. Besides, no M protein were found in serum protein electrophoresis and no elevation of total globulin. The clinical features of IgD type were similar to that of the light-chain type. The total chemotherapy efficacy rate of 89 patients who were treated with more than 3 cycles in our hospital is 61.8%, which has no difference in all types. Median overall survival of the 89 patients was 33.0 months.

CONCLUSION

IgG is the most common type in MM. Bone pain, anemia, hypercalcemia and renal insufficiency are common symptoms. Immunofixation electrophoresis should be performed routinely to avoid missed diagnosis of light-chain and IgD types of MM.

Influence of capsule endoscopy on the clinical outcomes of patients with obscure gastrointestinal bleeding: an analysis of 115 cases

AIM: To evaluate the accuracy of the diagnosis of OGIB by capsule endoscopy and the effectiveness of this technique in obtaining a suitable clinical outcome.

METHODS: From May 2002 to June 2005, 99 patients were enrolled in our study of capsule endoscopy for OGIB. We analyzed the degree of consistency between findings by capsule endoscopy and the clinical results, the outcome of treatments based on its diagnosis, the occurrence of re-bleeds and the re-examinations of the patients through records of consultations, emergencies or hospitalizations and telephone follow-up.

RESULTS: Capsule endoscopy successfully detected 89.9% of cases of OGIB. At a mean follow-up of 18.4 (6-41) months, lesions detected by capsule endoscope in 63 (63.6%) patients were verified. Among these patients, capsule endoscopy accurately diagnosed 90.5% (57/63) of OGIB cases, and this was not significantly different from the accuracy of diagnosis before validation (P = 0.36). Specific interventions were undertaken in 50.5% (50/99) of cases based on the findings of capsule endoscopy. The success rate of these specific strategies was 82% (41/50). Interventions based on positive findings in the small bowel are clearly more effective than those based on probable-positive findings (P = 0.01).

CONCLUSION: Capsule endoscopy has a high accuracy for the diagnosis of OGIB; this technique can efficiently guide further strategies and, in a relatively major proportion of cases, affect the clinical outcomes of these patients, especially bleeding caused by tumors, ulcers and angiodysplasia.

[Real-time measurement of noradrenaline release in central nervous system]

In order to investigate the central nervous mechanism and the diseases involved in catecholamine transmitter secretion, the dynamics of catecholamine release is studied in single cell, brain slice or in vivo. Noradrenaline is an important neurotransmitter and modulator in the central nervous system (CNS) and the peripheral nervous system (PNS). In the present paper, we first compared three real-time methods used to measure noradrenaline secretion in single cells (membrane capacitance, amperometry and confocal fluorescence microscopy imaging). Compared to the electrophysiological method and fluorescence microscopy, the basic usage of the carbon fiber electrode (CFE) in neuroscience research was presented as an example. Then, we presented a primary description of ion channels, including voltage-gated Na(+), K(+) and Ca(2+) channels in locus coeruleus (LC) neurons in rat brain slices. Finally, we presented example recordings of combined patch-clamp and amperometry measurements in LC neurons, indicating Ca(2+)-dependent quantal noradrenaline release following Ca(2+) influx through Ca(2+) channels.

[Expression and clinical significance of beta-catenin in multiple myeloma]

BACKGROUND & OBJECTIVE

beta-catenin is the pivotal regulator in Wnt pathway and in charge of cellular adhesion and signal conduction. Overexpression of beta-catenin has been observed in various human tumors. This study was to investigate the expression and clinical significance of beta-catenin in multiple myeloma (MM).

METHODS

Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect mRNA and protein expression of beta-catenin in bone marrow samples from 12 newly diagnosed MM patients, 14 relapsed/refractory MM patients, and 11 healthy donors. The clinical data and treatment outcomes of the MM patient were also analyzed.

RESULTS

The positive rate and the expression level of beta-catenin mRNA were significantly lower in healthy donors than in newly diagnosed patients and relapsed/refractory patients (27.3% vs. 75.0% and 100%, P=5.01e(-4); 0.35+/-0.17 vs. 0.72+/-0.11 and 0.85+/-0.16, P=5.88e(-5)); the mRNA level of beta-catenin was significantly lower in newly diagnosed patients than in relapsed/refractory patients (P=0.045). beta-catenin protein was not detected in healthy donors; while the positive rate and the expression level of beta-catenin protein were significantly lower in newly diagnosed patients than in relapsed/refractory patients (50.0% vs. 85.7%, 0.32+/-0.11 vs. 0.21+/-0.08, P=0.039). In the 10 newly diagnosed MM patients with evaluable treatment outcomes, the positive rate of beta-catenin protein was significant lower in the 7 patients without response than in the 3 patients showed response (14.3% vs. 100%, P=0.033). The positive rate of beta-catenin protein was significant higher in the 16 Durie/Salmon stage III patients than in the 10 stage II patients (87.5% vs. 40.0%, P=0.026), and significant higher in ISS stage III patients than in stage I and II patients (100% vs. 45.5% and 33.3%, P=0.006, P=0.032). The protein level of beta-catenin was positively correlated to serum levels of beta2-MG (r=0.688, P=0.002) and lactate dehydrogenase (LDH) (r=0.502, P=0.034).

CONCLUSION

The expression of beta-catenin is related with treatment outcome, Durin-Salmon stage and ISS stage of MM, and is positively correlated to serum levels of LDH and beta2-MG.

Clinical application of wireless capsule endoscopy in pediatric patients for suspected small bowel diseases

Capsule endoscopy (CE) has been demonstrated to be safe and well tolerated in adults with suspicion of small intestinal diseases with negative results of gastroscopy and colonoscopy. However, its value in pediatric patients has not yet been well studied. This study aimed to evaluate the results and safety of CE in pediatric patients with suspicion of small bowel disorders. There were 16 consecutive children and adolescents (12 boys, 4 girls) and 15 adults (9 men, 6 women) referred to us for suspected small bowel diseases from August 2002 to September 2005. Among the pediatrics, six patients were less than 10 years old. Technique for capsule placement, gastric transit time, small bowel transit time, excretion time of capsule endoscopy, capsule findings, and complications were recorded. All 16 pediatric patients described that the capsule was easy to swallow except for three children. Finally we delivered the capsule under gastroscopy with overtube for these three children. No capsule retention occurred during our study. Median recording time was 7 h 44 min (range 6 h 51 min-9 h 11 min). Median gastric transit time was 83.5 min (range 4-296 min). Median small bowel transit time was 270 min (range 142-484 min). Median excretion time of capsule was 33.9 h (range 12-96 h). There was no significant difference in excretion time of capsule, gastric transit time and small bowel transit time between pediatric patients and adult patients (P > 0.05). CE was positive in 12 patients, including Crohn's disease (4), hemangioma (2), angiodysplasia (2), Meckel diverticulum (1), polyp (1), aphthous ulcer in ascending colon (1), and cobblestone appearance of ileal mucosa. CE has been performed safely in a small series of pediatric patients after ingestion or endoscopic placement of the capsule. The high yield of abnormal findings was comparable to those of adult patients.

In vivo myocardial protection from ischemia/reperfusion injury by the peroxisome proliferator-activated receptor-gamma agonist rosiglitazone

BACKGROUND

Diabetes is associated with increased risk of mortality as a consequence of acute myocardial infarction. This study determined whether rosiglitazone (ROSI) could reduce myocardial infarction after ischemia/reperfusion injury.

METHODS AND RESULTS

Male Lewis rats were anesthetized, and the left anterior descending coronary artery was ligated for 30 minutes. After reperfusion for 24 hours, the ischemic and infarct sizes were determined. ROSI at 1 and 3 mg/kg IV reduced infarct size by 30% and 37%, respectively (P<0.01 versus vehicle). Pretreatment with ROSI (3 mg. kg(-1). d(-1) PO) for 7 days also reduced infarct size by 24% (P<0.01). ROSI also improved ischemia/reperfusion-induced myocardial contractile dysfunction. Left ventricular systolic pressure and positive and negative maximal values of the first derivative of left ventricular pressure (dP/dt) were significantly improved in ROSI-treated rats. ROSI reduced the accumulation of neutrophils and macrophages in the ischemic heart by 40% and 43%, respectively (P<0.01). Ischemia/reperfusion induced upregulation of CD11b/CD18 and downregulation of L-selectin on neutrophils and monocytes; these effects were significantly attenuated in ROSI-treated animals. Likewise, intercellular adhesion molecule-1 expression in ischemic hearts was markedly diminished by ROSI, as was the ischemia/reperfusion-stimulated upregulation of monocyte chemoattractant protein-1.

CONCLUSIONS

ROSI reduced myocardial infarction and improved contractile dysfunction caused by ischemia/reperfusion injury. The cardioprotective effect of ROSI was most likely due to inhibition of the inflammatory response.

Adenoviral delivery of a leukocyte-type 12 lipoxygenase ribozyme inhibits effects of glucose and platelet-derived growth factor in vascular endothelial and smooth muscle cells

The lipoxygenase (LO) pathway has been implicated as an important mediator of chronic glucose and platelet-derived growth factor (PDGF)-induced effects in the vascular system. Endothelial cells treated with 12LO products or cultured in high glucose showed enhanced monocyte adhesion, an important step in atherogenesis. We have previously reported that PDGF increased HETE levels in porcine aortic smooth muscle cells. Although several pharmacological inhibitors to the LO pathway are available, most lack specificity and may harbor undesirable side effects. Therefore, we developed a recombinant adenovirus expressing a hammerhead ribozyme (AdRZ) targeted against the porcine leukocyte-type 12LO mRNA to investigate the involvement of LO in glucose- and PDGF-mediated effects in vascular cells. Infection of porcine aortic endothelial cells with AdRZ reduced the level of glucose-enhanced 12LO mRNA expression as determined by quantitative, real-time reverse transcriptase-polymerase chain reaction. Reverse-phase HPLC and RIA analysis also revealed a corresponding decrease in glucose-stimulated 12HETE production in both the cellular and supernatant fractions. In the ribozyme-treated porcine aortic endothelial cells, there was marked inhibition of high glucose-stimulated monocyte adhesion. Infection with AdRZ also reduced PDGF-induced porcine aortic smooth muscle cell migration by approximately 50%. These studies demonstrate the efficacy of recombinant adenovirus expressing 12LO ribozyme in studying the effects of 12LO in vascular wall cells. They document an important role for the 12LO pathway in regulating inflammatory changes in endothelial cells and smooth muscle cells.

12-lipoxygenase is increased in glucose-stimulated mesangial cells and in experimental diabetic nephropathy

BACKGROUND

Arachidonic acid-derived 12-lipoxygenase (12-LO) products have potent growth and chemotactic properties. The present studies examined whether 12-LO and fibronectin are induced in cultured rat mesangial cells (MCs) exposed to high glucose and whether they are expressed in experimental diabetic nephropathy.

METHODS

To determine the effect of high glucose on MC 12-LO mRNA and protein expression, rat MCs were incubated with RPMI medium containing 100 (NG) or 450 mg/dL glucose (HG). For animal studies, rats were injected with diluent (control) or streptozotocin. The latter were left untreated (DM) or treated with insulin (DM + I). At sacrifice after four months, GAPDH, 12-LO, and fibronectin mRNA were measured by competitive reverse transcription-polymerase chain reaction (RT-PCR) in microdissected glomeruli (G). Renal sections were semiquantitatively scored (0 to 4+) for diabetic changes and for 12-LO and fibronectin by immunohistochemistry.

RESULTS

12-LO mRNA expression in MC exposed to HG (12.71 +/- 1.17 attm/microL) and DM G (1.78 +/- 0.65 x 10-3 attm/glomerulus) was significantly higher than those of MCs in NG media (6.71 +/- 0.78 attm/microL) and control G (0.34 +/- 0.12 x 10-3 attm/glomerulus, P < 0.005), respectively. Western blot revealed a 1.7- and a 2.8-fold increase in MC and G 12-LO protein expression, respectively (P < 0.05). The immunohistochemistry score for G 12-LO and diabetic nephropathy score was significantly greater in DM and DM + I than controls. MC and G GAPDH mRNA remained unchanged.

CONCLUSIONS

In MCs exposed to HG and in diabetic rat glomeruli, increments in 12-LO mRNA and protein are associated with changes modeling diabetic nephropathy. These findings suggest a role for the 12-LO pathway in the pathogenesis of diabetic nephropathy.

Ribozyme-mediated inhibition of rat leukocyte-type 12-lipoxygenase prevents intimal hyperplasia in balloon-injured rat carotid arteries

BACKGROUND

12-Lipoxygenase (12-LO) products of arachidonate metabolism have growth and chemotactic effects in vascular smooth muscle cells. We have also recently demonstrated increased 12-LO mRNA and protein expression in the neointima of balloon-injured rat carotid arteries. In this study, we evaluated whether 12-LO activation plays a role in neointimal thickening in this rat model by using a specific ribozyme (Rz) directed to rat 12-LO.

METHODS AND RESULTS

We designed a chimeric DNA-RNA hammerhead Rz to cleave rat leukocyte-type 12-LO mRNA. This Rz dose-dependently cleaved a 166-nucleotide target 12-LO mRNA substrate in vitro and reduced 12-LO mRNA and protein expression in rat vascular smooth muscle cells. A control mutant Rz (MRz) with a point mutation in the catalytic site was inactive. To test the in vivo efficacy of the 12-LO Rz, the left common carotid arteries of rats were injured with a balloon catheter. The distal half of the injured arteries was treated with Rz or MRz mixed with lipofectin. The proximal half received only lipofectin. Twelve days after injury, intima-to-media ratios were significantly lower in the Rz-treated sections than in untreated sections from the same rat (0.742+/-0.16 versus 1.749+/-0.12, P:<0.001). In contrast, the MRz had no significant effect.

CONCLUSIONS

These results indicate the important role of the leukocyte-type 12-LO pathway in restenosis in response to injury.

Extracellular signal-regulated kinase plays an essential role in hypertrophic agonists, endothelin-1 and phenylephrine-induced cardiomyocyte hypertrophy

The extracellular signal-regulated kinase (ERK) pathway is activated by hypertrophic stimuli in cardiomyocytes. However, whether ERK plays an essential role or is implicated in all major components of cardiac hypertrophy remains controversial. Using a selective MEK inhibitor, U0126, and a selective Raf inhibitor, SB-386023, to block the ERK signaling pathway at two different levels and adenovirus-mediated transfection of dominant-negative Raf, we studied the role of ERK signaling in response of cultured rat cardiomyocytes to hypertrophic agonists, endothelin-1 (ET-1), and phenylephrine (PE). U0126 and SB-386023 blocked ET-1 and PE-induced ERK but not p38 and JNK activation in cardiomyocytes. Both compounds inhibited ET-1 and PE-induced protein synthesis and increased cell size, sarcomeric reorganization, and expression of beta-myosin heavy chain in myocytes with IC(50) values of 1-2 microm. Furthermore, both inhibitors significantly reduced ET-1- and PE-induced expression of atrial natriuretic factor. In cardiomyocytes transfected with a dominant-negative Raf, ET-1- and PE-induced increase in cell size, sarcomeric reorganization, and atrial natriuretic factor production were remarkably attenuated compared with the cells infected with an adenovirus-expressing green fluorescence protein. Taken together, our data strongly support the notion that the ERK signal pathway plays an essential role in ET-1- and PE-induced cardiomyocyte hypertrophy.

Selective estrogen receptor modulator idoxifene inhibits smooth muscle cell proliferation, enhances reendothelialization, and inhibits neointimal formation in vivo after vascular injury

BACKGROUND

Idoxifene (ID) is a tissue-selective estrogen receptor modulator (SERM). The pharmacological profile of ID in animal studies suggests that it behaves like an estrogen receptor (ER) agonist in bone and lipid metabolism while having negligible ER activity on the reproductive system. It is unknown whether ID retains the vascular protective effects of estrogen.

METHODS AND RESULTS

In cultured vascular smooth muscle cells (VSMCs), ID inhibited platelet-derived growth factor-induced DNA synthesis and mitogenesis with IC(50) values of 20.4 and 27.5 nmol/L, respectively. Treatment with ID resulted in S-phase cell cycle arrest in serum-stimulated VSMCs. ID 1 to 100 nmol/L significantly protected endothelial cells from tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis in vitro. Virgin Sprague-Dawley rats ovariectomized 1 week before the study were treated with ID (1 mg x kg(-1) x d(-1)) or vehicle by gavage for 3 days before balloon denudation in carotid artery. The SMC proliferation in injured vessels was determined by immunostaining for proliferating cell nuclear antigen (PCNA). The number of PCNA-positive SMCs was reduced by 69%, 82%, and 86% in the media at days 1, 3 and 7, respectively, and by 78% in the neointima at day 7 after injury in ID- versus vehicle-treated group (P:<0.01). ID significantly enhanced reendothelialization in the injured carotid arteries as determined by Evans blue stain and immunohistochemical analysis for von Willebrand factor. In the former assay, the reendothelialized area in injured vessels was 43% in ID-treated group versus 24% in the vehicle group (P:<0.05); in the latter assay, the numbers of von Willebrand factor-positive cells per cross section increased from 24. 8 (vehicle) to 60.5 (ID) (P:<0.01) at day 14 after injury. In addition, the production of nitric oxide from excised carotid arteries was significantly higher in ID-treated than the vehicle group (8.5 versus 2.7 nmol/g, P:<0.01). Finally, ID treatment reduced neointimal area and the ratio of intima to media by 45% and 40%, respectively (P:<0.01), at day 14 after balloon angioplasty.

CONCLUSIONS

The results indicate that ID beneficially modulates the balloon denudation-induced vascular injury response. Inhibition of VSMC proliferation and acceleration of endothelial recovery likely mediate this protective effect of ID.

Nitric oxide stimulatory and endothelial protective effects of idoxifene, a selective estrogen receptor modulator, in the splanchnic artery of the ovariectomized rat

Estrogen is known to stimulate endothelial nitric oxide production and attenuate endothelial dysfunction after ischemia and reperfusion. However, estrogen therapy increases the risk of breast and endometrial cancer. The present study was designed to determine whether idoxifene, a selective estrogen receptor modulator without adverse effects on reproductive organs, may stimulate nitric oxide release and protect endothelial function. In U-46619 precontracted superior mesenteric arterial (SMA) segments isolated from ovariectomized rats, idoxifene and 17 beta-estradiol resulted in a comparable dose-dependent vasorelaxation (maximal relaxation: 75.3 +/- 4.9 and 71 +/- 4.7%, respectively). Treatment of the rings with N(omega)-nitro-L-arginine methyl ester completely blocked idoxifene- and 17 beta-estradiol-induced vasorelaxation. In vitro incubation of SMA rings with TNF alpha significantly reduced vasorelaxation to an endothelium-dependent vasodilator, acetylcholine (maximal relaxation: 73 +/- 3.7 versus 95 +/- 2.9% pre-TNF alpha, P <.01). Idoxifene, but surprisingly not 17 beta-estradiol, prevented TNF alpha-induced endothelial dysfunction (maximal relaxation: 86 +/- 2.6% in idoxifene-treated rings and 77 +/- 5.1% in 17beta-estrogen-treated rings). In vivo ischemia and reperfusion resulted in significant endothelial dysfunction as evidenced by decreased vasorelaxation to acetylcholine (maximal relaxation: 48 +/- 5.5 versus 92 +/- 3.9% in normal SMA rings), but a normal relaxation response to an endothelium-independent vasodilator, acidified NaNO(2) (95 +/- 3.2%). Treatment with idoxifene at either 1 or 2 mg/kg/day, or 17beta-estrogen at 1 mg/kg/day for 4 days significantly preserved endothelial function (P <.01 versus vehicle). Taken together, these results demonstrate that idoxifene is an endothelium-dependent vasodilator and exerts significant endothelial protective effects against TNF alpha- and ischemia-reperfusion-induced endothelial injury. These results suggest that selective estrogen receptor modulators have therapeutic potential in diseases where endothelial dysfunction plays an important role.

Direct genetic demonstration of G alpha 13 coupling to the orphan G protein-coupled receptor G2A leading to RhoA-dependent actin rearrangement

G2A is an orphan G protein-coupled receptor (GPCR), expressed predominantly in T and B cells and homologous to a small group of GPCRs of unknown function expressed in lymphoid tissues. G2A is transcriptionally induced in response to diverse stimuli, and its ectopic expression suppresses transformation of B lymphoid precursors by BCR-ABL. G2A induces morphological transformation of NIH 3T3 fibroblasts. Microinjection of constructs encoding G2A into Swiss 3T3 fibroblasts induces actin reorganization into stress fibers that depends on RhoA, but not CDC42 or RAC. G2A elicits RhoA-dependent transcriptional activation of serum response factor. Direct evaluation of RhoA activity demonstrates elevated levels of RhoA-GTP in G2A-expressing cells. Microinjection of embryonic fibroblasts derived from various G alpha knockout mice establishes a requirement for G alpha 13 but not G alpha 12 or G alpha q/11 in G2A-induced actin rearrangement. In conclusion, G2A represents a family of GPCRs expressed in lymphocytes that may link diverse stimuli to cytoskeletal reorganization and transcriptional activation through a pathway involving G alpha 13 and RhoA.

A comparison of carvedilol and metoprolol antioxidant activities in vitro

Carvedilol is a vasodilating beta-blocker and antioxidant approved for treatment of mild to moderate hypertension. angina, and congestive heart failure. Metoprolol is a beta1-selective adrenoceptor antagonist. When carvedilol and metoprolol were recently compared in clinical trials for heart failure, each showed beneficial beta-blocker effects such as improved symptoms, quality of life, exercise tolerance, and ejection fraction, with no between-group differences. When thiobarbituric acid reactive substance (TBARS) levels were measured in serum as an indirect marker of free radical activity, there were also no between-group differences. However, we had noted superior cardioprotection by carvedilol in comparison to metoprolol in ischemia and reperfusion models. We therefore examined antioxidant activity directly in cells and tissues. Here we show that in cultured rat cerebellar neurons, and in brain and heart membranes, carvedilol has far greater antioxidant activity than metoprolol, which is essentially inactive as an antioxidant in these model systems. The antioxidant activity of carvedilol could be explained by a greater degree of lipophilicity, as measured by its ClogP value of 3.841 as contrasted to a ClogP value of 1.346 for metoprolol. Alternatively, the molecular structure of carvedilol favors redox recycling, which the structure of metoprolol does not. Therefore, carvedilol could have additional pharmacologic effects that are favorable for long-term therapy.

[The separation of three basic drugs with carboxymethyl-poly-beta-cyclodextrin as chiral additive by capillary electrophoresis]

Five cyclodextrin derivatives, namely phosphate ester beta-CD, carboxymethyl-beta-CD(CM-beta-CD), bis-[6-oxygen-(beta-carboxymethyl-succinic acid-4-ester)] beta-CD(F-CM-beta-CD), beta-CD polymer(P-beta-CD), carboxymethyl-poly-beta-CD (CD-P-beta-CD), were used as chiral selector for separation of three basic drugs, lobeline, thiopendonesodium, flunarizine by capillary zone electrophoresis (CZE). All the five cyclodextrins have chiral separation ability to lobeline. P-beta-CD and CM-P-beta-CD have chiral recognition to thiopentonesodium and flunarizine. The results indicate that via optimizing separation conditions by varying pH and the concentration of chiral selectors the three racemic drugs could be baseline separated with 2% P-beta-CD or 0.5% CM-P-beta-CD in the buffer of 30 mmol/L Tris-H3PO4. And the best resolution ranging from 4 to 35 with CM-P-beta-CD as chiral additive was obtained within 10 min. The results were much better than those reported in other references.

Inhibition of extracellular signal-regulated kinase enhances Ischemia/Reoxygenation-induced apoptosis in cultured cardiac myocytes and exaggerates reperfusion injury in isolated perfused heart

Three major mammalian mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK), p38, and c-Jun NH(2)-terminal protein kinase (JNK), have been identified in the cardiomyocyte, but their respective roles in the heart are not well understood. The present study explored their functions and cross talk in ischemia/reoxygenation (I/R)-induced cardiac apoptosis. Exposing rat neonatal cardiomyocytes to ischemia resulted in a rapid and transient activation of ERK, p38, and JNK. On reoxygenation, further activation of all 3 mitogen-activated protein kinases was noted; peak activities increased (fold) by 5.5, 5.2, and 6.2, respectively. Visual inspection of myocytes exposed to I/R identified 18.6% of the cells as showing morphological features of apoptosis, which was further confirmed by DNA ladder and terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL). Myocytes treated with PD98059, a MAPK/ERK kinase (MEK1/MEK2) inhibitor, displayed a suppression of I/R-induced ERK activation, whereas p38 and JNK activities were increased by 70.3% and 55.0%, respectively. In addition, the number of apoptotic cells was increased to 33.4%. With pretreatment of cells with SB242719, a selective p38 inhibitor, or SB203580, a p38 and JNK2 inhibitor, I/R+PD98059-induced apoptotic cells were reduced by 42.8% and 63.3%, respectively. Hearts isolated from rats treated with PD98059 and subjected to global ischemia (30 minutes)/reoxygenation (1 hour) showed a diminished functional recovery compared with the vehicle group. Coadministration of SB203580 attenuated the detrimental effects of PD98059 and significantly improved cardiac functional recovery. The data taken together suggest that ERK plays a protective role, whereas p38 and JNK mediate apoptosis in cardiomyocytes subjected to I/R, and the dynamic balance of their activities is critical in determining cardiomyocyte fate subsequent to reperfusional injury.

[A novel chiral selector in capillary electrophoresis--beta-cyclodextrin polymer]

Three chiral selectors CM-beta-CD, EP-beta-CD, beta-CD were studied for the enatio-separation of three drugs under optimum conditions respectively. The results demonstrate that the resolving power for the drugs is as follows CM-beta-CD > EP-beta-CD > beta-CD, with the exception of lobeline. This is due to the--CH2COOCH3 group of CM-beta-CD, which will change the combination and improve the recognition on guest molecules. Although EP-beta-CD is inferior to CM-beta-CD for the separation of chlorpheniramine and verapamil, it has excellent recognition on lobeline and it has not been reported previously. In most cases EP-beta-CD is superior to beta-CD. The explanations are: (1) EP-beta-CD has good solubility in water, which enables high concentrations to be used and consequently achieves excellant separation of racemic compounds, (2) the polymerization of beta-CD changes the properties of CD units and the process produces a more rigid and different conformation from CD, (3) we must attribute much merits to the cooperation or synergism of two, three or even more CD moieties of two polymers for inclusion. Complexation with analytes possesses more than one guest part in their structure.

[Study on the separation of optical chromatography]

The relationship between the particle radius with the intensity of the applied laser radiation force is theoretically studied using a ray-optics model by analyzing the forced-status of the separated particles in the mobile phase. The laser radiation force is proportional to the square of the particle radius when the particle radius is much smaller than the laser beam radius under the condition of using a single-transverse-mode laser beam with a Gaussian intensity distribution and the particle refractive index being larger than that of the mobile phase. The retention distance is calculated and the dynamic range is discussed. Theoretically, the dynamic range of the optical chromatography can be extended by increasing laser power, decreasing the flow rate of mobile phase and focusing the laser beam.

BMP-2 gene expression and effects on human vascular smooth muscle cells

Bone morphogenetic proteins (BMPs) and their serine/threonine kinase receptors have been identified in atherosclerotic arteries and vascular smooth muscle cells, respectively. Thus, BMPs (the largest subfamily of the TGF-beta superfamily) have been implicated in the pathogenesis of atherosclerosis. However, the origins of BMP biosynthesis and the functional roles of BMP in blood vessels are unclear. The present study explored BMP-2 gene expression in various human blood vessels and vascular cell types. Functional in vitro studies were also performed to determine the effects of recombinant human BMP-2 on migration (transwell assay) and proliferation ([3H]-thymidine incorporation) of human aortic vascular smooth muscle cells (HASMC). RT-PCR experiments revealed BMP-2 gene expression in normal and atherosclerotic human arteries as well as cultured human aortic and coronary vascular smooth muscle cells, human umbilical vein endothelial cells (HUVECs) and human macrophages. In cellular migration studies, incubation with BMP-2 produced efficacious (</=610-fold), concentration- and time-dependent chemotaxis of HASMCs (EC50 = 0.8 microM) with little or no effect on HUVEC chemotaxis. The increased HASMC motility induced by BMP-2 was inhibited by coincubation with an anti-BMP-2 mAb. In addition, subthreshold concentrations of BMP-2 produced a dramatic synergistic effect upon platelet-derived growth factor (PDGF)-induced chemotaxis. In contrast to PDGF, BMP-2 had no significant effet on [3H]-thymidine incorporation in HASMC at chemotaxic concentrations (</=6.0 microM) nor did it synergize with the mitogenic effects of PDGF. In conclusion, the expression of BMP-2 by numerous cell types in the blood vessel wall may play a chemotactic or cochemotactic role in the smooth muscle cell response to vascular injury.

Evidence for 12-lipoxygenase induction in the vessel wall following balloon injury

OBJECTIVE

Vascular smooth muscle cell (VSMC) migration and proliferation are key events in the development of atherosclerosis and restenosis following angioplasty. These events are mediated by several growth factors and cytokines whose cellular effects include activation of phospholipases and arachidonic acid metabolism via the lipoxygenase (LO) pathway. Since 12-LO products have potent growth and chemotactic effects, we have examined if 12-LO is upregulated in the neointima of injured rat carotid arteries and also if LO inhibition could attenuate neointimal thickening.

METHODS

The left common carotid arteries of male Sprague Dawley rats were injured using a 1.8 F PTCA balloon catheter. Four-fourteen days after injury, injured and uninjured tissue samples were processed for histology, and immunohistochemistry or polymerase chain reaction (PCR) to examine 12-LO expression.

RESULTS

Twelve days after injury, immunohistochemical staining with a 12-LO antibody revealed intense staining in injured left carotid arteries, mainly in neointimal VSMCs and inflammatory cells, but not in the uninjured right arteries. There was also a marked upregulation of 12-LO mRNA (over five-fold by competitive PCR) in the injured arteries. Treatment of the arteries with a LO inhibitor, phenidone, soon after injury resulted in significant inhibition of neointimal thickening. In contrast, a cyclooxygenase inhibitor, ibuprofen, had no effect.

CONCLUSIONS

These results indicate for the first time that balloon injury results in marked induction of 12-LO mRNA and protein expression in the vessel wall. Furthermore, LO pathway activation may mediate, at least in part, the development of the lesion or plaque instability, suggesting a novel target for therapeutic intervention to block these pathological events.

TL1, a novel tumor necrosis factor-like cytokine, induces apoptosis in endothelial cells. Involvement of activation of stress protein kinases (stress-activated protein kinase and p38 mitogen-activated protein kinase) and caspase-3-like protease

TL1 is a recently discovered novel member of the tumor necrosis factor (TNF) cytokine family. TL1 is abundantly expressed in endothelial cells, but its function is not known. The present study was undertaken to explore whether TL1 induces apoptosis in endothelial cells and, if so, to explore its mechanism of action. Cultured bovine pulmonary artery endothelial cells (BPAEC) exposed to TL1 showed morphological (including ultrastructural) and biochemical features characteristic of apoptosis. TL1-induced apoptosis in BPAEC was a time- and concentration-dependent process (EC50 = 72 ng/ml). The effect of TL1 was not inhibited by soluble TNF receptors 1 or 2. TL1 up-regulated Fas expression in BPAEC at 8 and 24 h after treatment, and significantly activated stress-activated protein kinase (SAPK) and p38 mitogen-activated protein kinase (p38 MAPK). The peak activities of SAPK and p38 MAPK in TL1-treated BPAEC were increased by 9- and 4-fold, respectively. TL1-induced apoptosis in the BPAEC was reduced by expression of a dominant-interfering mutant of c-Jun (62.8%, p < 0.05) or by a specific p38 inhibitor, SB203580 (1-10 microM) dose-dependently. TL1 also activated caspases in BPAEC, and TL1-induced apoptosis in BPAEC was significantly attenuated by the caspase inhibitor, ZVAD-fluromethyl-ketone. The major component activated by TL1 in BPAEC was caspase-3, which was based on substrate specificity and immunocytochemical analysis. These findings suggest that TL1 may act as an autocrine factor to induce apoptosis in endothelial cells via activation of multiple signaling pathways, including stress protein kinases as well as certain caspases.

Carvedilol inhibits activation of stress-activated protein kinase and reduces reperfusion injury in perfused rabbit heart

Stress-activated protein kinase (SAPK/JNK) has been implicated in the signaling pathway that leads to cell death. Carvedilol, a new vasodilating beta-adrenoceptor antagonist with potent antioxidant activity, has been shown to convey a high degree of cardioprotection in a variety of experimental models of myocardial ischemia as well as in patients with congestive heart failure. The present study was designed to explore whether the cardioprotective effects of carvedilol involve inhibition of SAPK activation. Ex vivo ischemia (30 min)-reperfusion (60-120 min) of the rabbit heart resulted in 67% reduction of pressure-rate product, 45% necrosis of left ventricular tissue and 62% loss of myocardial creatine kinase (P < 0.01 vs. basal). SAPK levels in the perfused hearts increased markedly following reperfusion (5.6-fold increase, P < 0.01 vs. basal). Carvedilol, at 10 microM, administered at time of reperfusion, enhanced recovery of pressure-rate product by 61%, reduced necrotic size by 65% and decreased myocardial creatine kinase loss by 62% (P < 0.01 vs. vehicle). Carvedilol also inhibited reperfusion-induced activation of SAPK by 61% (P<0.01 vs. vehicle). Carvedilol, at 1 microM, displayed a trend of cardioprotection and inhibition of SAPK activation. Our results suggest that SAPK may play a role in ischemia/reperfusion-induced cardiac injury and inhibition of SAPK activation by carvedilol may contribute to its cardioprotective effects.

Staurosporine-induced apoptosis in cardiomyocytes: A potential role of caspase-3

Cardiomyocyte apoptosis has been demonstrated in animal models of cardiac injury as well as in patients with congestive heart failure or acute myocardial infarction. Therefore, apoptosis has been proposed as an important process in cardiac remodeling and progression of myocardial dysfunction. However, the mechanisms underlying cardiac apoptosis are poorly understood. The present study was designed to determine whether the family of caspase proteases and stress-activated protein kinase (SAPK/JNK) are involved in cardiac apoptosis. Cultured rat neonatal cardiac myocytes were treated with staurosporine to induce apoptosis as evidenced by the morphological (including ultrastructural) characteristics of cell shrinkage, cytoplasmic and nuclear condensation, and fragmentation. Nucleosomal DNA fragmentation in myocytes was further identified by agarose gel electrophoresis (DNA ladder) as well as in situ nick end-labeling (TUNEL). Staurosporine-induced apoptosis in myocytes was a time- and concentration-(0.25-1 micro M)-dependent process. Staurosporine-induced apoptosis in myocytes was reduced by a cell-permeable, irreversible tripeptide inhibitor of caspases, ZVAD-fmk, but not by the ICE-specific inhibitor, Ac-YVAD-CHO. At 10, 50 and 100 muM of ZVAD-fmk, staurosporine-induced myocyte apoptosis was reduced by 5.8, 39.1 (P<0.01) and 53.8% (P<0.01), respectively. Staurosporine, at 0.25-1 micro M, increased caspase activity in cardiomyocytes by five- to eight-fold, peaking at 4-8 h after stimulation. Based on substrate specificity analysis, the major component of caspases activated in myocytes was consistent with caspase-3 (CPP32). Moreover, the appearance of the 17-kD subunit of active caspase-3 in staurosporine-treated myocytes was demonstrated by immunocytochemical analysis. In contrast, staurosporine induced a rapid and transient inhibition of SAPK/JNK in myocytes. The SAPK activity in myocytes was reduced by 68.3 and 58.3% (P<0.01 v basal) at 10 and 30 min after treatment with 1 micro M of staurosporine, respectively. Our results suggest that staurosporine-induced cardiac myocyte apoptosis involves activation of caspases, mainly caspase-3, but not activation of the SAPK signaling pathway.

Possible involvement of stress-activated protein kinase signaling pathway and Fas receptor expression in prevention of ischemia/reperfusion-induced cardiomyocyte apoptosis by carvedilol

Carvedilol, a new vasodilating beta-adrenoceptor antagonist and a potent antioxidant, produces a high degree of cardioprotection in a variety of experimental models of ischemic cardiac injury. Recent clinical studies in patients with heart failure have demonstrated that carvedilol reduces morbidity and mortality and inhibits cardiac remodeling. The present study was designed to explore whether the protective effects of carvedilol on the ischemic myocardium include inhibition of apoptosis of cardiomyocytes and, if so, to determine its mechanism of action. Anesthetized rabbits were subjected to 30 minutes of coronary artery occlusion followed by 4 hours of reperfusion. Detection of apoptosis of cardiomyocytes was based on the presence of nucleosomal DNA fragments on agarose gels (DNA ladder) and in situ nick end labeling. Carvedilol (1 mg/kg IV), administered 5 minutes before reperfusion, reduced the number of apoptotic myocytes in the ischemic area from 14.7 +/- 0.4% to 3.4 +/- 1.8% (77% reduction, P<.001). Propranolol, administered at equipotent beta-blocking dosage, reduced the number of apoptotic myocytes to 8.9 +/- 2.1% (39% reduction, P<.05). DNA ladders were observed in the hearts of all six vehicle-treated rabbits but only one of six carvedilol-treated rabbits (P<.01). Immunocytochemical analysis of rabbit hearts demonstrated an upregulation of Fas protein in ischemic cardiomyocytes, and treatment with carvedilol reduced both the intensity of staining as well as the area stained. Myocardial ischemia/reperfusion led to a rapid activation of stress-activated protein kinase (SAPK) in the ischemic area but not in nonischemic regions. SAPK activity was increased from 2.1 +/- 0.3 mU/mg (basal) to 8.9 +/- 0.8 mU/mg after 30 minutes of ischemia followed by 20 minutes of reperfusion. Carvedilol inhibited the activation of SAPK by 53.4 +/- 6.5% (P<.05). Under the same conditions, propranolol (1 mg/kg) had no effect on SAPK activation. Taken together, these results suggest that carvedilol prevents myocardial ischemia/reperfusion-induced apoptosis in cardiomyocytes possibly by downregulation of the SAPK signaling pathway, by inhibition of Fas receptor expression, and by beta-adrenergic blockade. The former two actions represent novel and important mechanisms that may contribute to the cardioprotective effects of carvedilol.

The role of 12-lipoxygenase in pancreatic -cells (Review)

Leukocyte type 12-lipoxygenase (12-LO) catalyzes the conversion of arachidonic acid (AA; C20:4) to 12-hydroperoxyeicosatetraenoic acid (12-HPETE) and linoleic acid (LA; C18:2) to 13-hydroperoxyoctadecadienoic acid (13-HPODE). Previous studies have demonstrated that 12-LO, but not 5- or 15-lipoxygenase (5-LO, 15-LO respectively), is specifically expressed in pancreatic -cells and is involved in regulating glucose-stimulated insulin secretion. Lipoxygenase products also have been linked with inflammatory pathways in endothelial cells, kidney mesangial cells, inflammatory bowel disease, and corneal epithelial cells. Therefore, 12-LO may play a role in cytokine mediated inflammation in pancreatic beta-cells (i.e. beta -cell dysfunction and cytotoxicity). Cytokines such as IL-1 stimulate both de novo 12-LO protein synthesis and enzyme activity in pancreatic beta-cells. The products generated by 12-LO may ultimately be involved in cellular events that lead to lipid peroxidation. Hydroperoxide and free radical production in beta-cells can activate intracellular signaling pathways that lead to cell death or may directly damage mitochondrial and plasma membranes. Increased 12-LO expression has also been found in islets from prediabetic Zucker fatty rats, a model that demonstrates insulin secretory defects similar to human type 2 diabetes. In this review, we present an overview of the 12-LO pathway in regulating glucose-stimulated insulin secretion in beta-cells as well as more recent data which supports the hypothesis that the 12-LO pathway participates in cytokine mediated beta-cell dysfunction and cytotoxicity.

Use of a hammerhead ribozyme with cationic liposomes to reduce leukocyte type 12-lipoxygenase expression in vascular smooth muscle

Chemically synthesized hammerhead-type ribozymes targeted against the porcine leukocyte-type 12-lipoxygenase (LO) have been developed and studied. One chimeric ribozyme consists of DNA in the non-enzymatic portions, and RNA in the enzymatic core as well as two phosphorothioate internucleotide linkages at 3' terminus. The second ribozyme consists of ribonucleotide sequences generated by in vitro transcription. In this chapter we describe methodologies to first analyze the ribozyme catalytic activity in vitro by studying cleavage of target RNA in vitro. The subsequent sections will describe how to target the catalytic ribozyme and deliver it to porcine vascular smooth muscle cells (PVSMC) by a liposome-mediated method. Finally ways to evaluate its activity to inhibit expression of the 12-LO mRNA will be presented. These results demonstrate the feasibility of using ribozymes as novel candidates for therapeutic agents to block specific gene expression in vascular cells.

2-Methoxyestradiol, an endogenous estrogen metabolite, induces apoptosis in endothelial cells and inhibits angiogenesis: possible role for stress-activated protein kinase signaling pathway and Fas expression

2-Methoxyestradiol (2-ME) is an endogenous metabolite of estradiol-17beta and the oral contraceptive agent 17-ethylestradiol. 2-ME was recently reported to inhibit endothelial cell proliferation. The current study was undertaken to explore the mechanism of 2-ME effects on endothelial cells, especially whether 2-ME induces apoptosis, a prime mechanism in tissue remodeling and angiogenesis. Cultured bovine pulmonary artery endothelial cells (BPAEC) exposed to 2-ME showed morphological (including ultrastructural) features characteristic of apoptosis: cell shrinkage, cytoplasmic and nuclear condensation, and cell blebbing. 2-ME-induced apoptosis in BPAEC was a time- and concentration-dependent process (EC50 = 0.45 +/- 0.09 microM, n = 8). Nucleosomal DNA fragmentation in BPAEC treated with 2-ME was identified by agarose gel electrophoresis (DNA ladder) as well as in situ nick end labeling. Under the same experimental conditions, estradiol-17beta and two of its other metabolites, estriol and 2-methoxyestriol (< or =10 microM), did not have an apoptotic effect on BPAEC. 2-ME activated stress-activated protein kinase (SAPK)/c-Jun amino-terminal protein kinase in BPAEC in a concentration-dependent manner. The activity of SAPK was increased by 170 +/- 27% and 314 +/- 22% over the basal level in the presence of 0.4 and 2 microM 2-ME (n = 3-6), respectively. The activation of SAPK was detected at 10 min, peaked at 20 min, and returned to basal levels at 60 min after exposure to 2-ME. Inhibition of SAPK/c-Jun amino-terminal protein kinase activation by basic fibroblast growth factor, insulin-like growth factor, or forskolin reduced 2-ME-induced apoptosis. Immunohistochemical analysis of BPAEC indicated that 2-ME up-regulated expression of both Fas and Bcl-2. In addition, 2-ME inhibited BPAEC migration (IC50 = 0.71 +/- 0.11 microM, n = 4) and basic fibroblast growth factor-induced angiogenesis in the chick chorioallantoic membrane model. Taken together, these results suggest that promotion of endothelial cell apoptosis, thereby inhibiting endothelial cell proliferation and migration, may be a major mechanism by which 2-ME inhibits angiogenesis.

Increased 12-lipoxygenase expression in breast cancer tissues and cells. Regulation by epidermal growth factor

The interaction of growth factors, such as epidermal growth factor (EGF) with their receptors, on breast cancer cells can lead to the hydrolysis of phospholipids and release of fatty acids, such as arachidonic acid, which can be further metabolized by the lipoxygenase (LO) pathway. Several LO products have been shown to stimulate oncogenes and have mitogenic and chemotactic effects. In this study, we have evaluated the regulation of 12-LO activity and expression in breast cancer cells and tissues. Leukocyte-type 12-LO messenger RNA (mRNA) expression was studied by a specific RT-PCR method in matched, normal, uninvolved and cancer-involved breast tissue RNA samples from six patients. In each of these six patients, the cancer-involved section showed a much higher level of 12-LO mRNA than the corresponding normal section. 12-LO mRNA levels also were greater in two breast cancer cell lines, MCF-7 and COH-BR1, compared with the nontumorigenic breast epithelial cell line, MCF-10F. The growth of the MCF-7 cells was significantly inhibited by two specific LO blockers but not by a cyclooxygenase blocker. Treatment of serum-starved MCF-7 cells with EGF for 4 h led to a dose-dependent increase in the formation of the 12-LO product, 12-hydroxyeicosatetraenoic acid. EGF treatment also increased the levels of the leukocyte-type 12-LO protein expression at 24 h. These results suggest that activation of the 12-LO pathway may play a key role in basal and EGF-induced breast cancer cell growth.

Platelet-derived growth factor BB mediated regulation of 12-lipoxygenase in porcine aortic smooth muscle cells

Platelet-derived growth factor BB (PDGF) is a potent mitogen and chemoattractant for vascular smooth muscle cells (VSMC). In the present study, we have examined the effect of PDGF on the 12-lipoxygenase (12-LO) pathway of arachidonate metabolism in porcine aortic VSMC (PVSMC). The rationale for this is previous studies showing that LO products have growth and chemotactic effects in VSMC and that another VSMC growth factor, angiotensin II, is a potent positive regulator of 12-LO activity and expression. We observed that PDGF causes a significant increase in the formation of the 12-LO product, 12-hydroxyeicosatetraenoic acid (12-HETE) in PVSMC. In addition, PDGF also markedly increased leukocyte-type 12-LO messenger RNA and protein expression. PDGF-induced PVSMC migration was inhibited significantly by two LO blockers but not by a cyclooxygenase blocker. Furthermore, although the proliferative effects of PDGF on PVSMC were not altered by cell culture under hyperglycemic conditions (25 mM glucose, HG), the chemotactic effects of PDGF as well as those of 10% fetal calf serum were significantly greater in cells cultured in HG as compared to normal glucose conditions (5.5 mM), thus indicating a potential new mechanism for the accelerated cardiovascular disease usually observed in diabetes. These results indicate a novel mechanism for the biological effects of PDGF in leading to cardiovascular disease.

Osteopontin expression in platelet-derived growth factor-stimulated vascular smooth muscle cells and carotid artery after balloon angioplasty

Osteopontin (OPN), an arginine-glycine-aspartate (RGD)-containing adhesive glycoprotein, is constitutively expressed in rat aorta and carotid arteries and is markedly elevated in response to vascular injury. OPN is chemotactic for vascular smooth muscle cells (SMCs), suggesting a role in vascular remodeling. However, the mechanism for the regulation of OPN expression is poorly understood. In the present study, the effect of platelet-derived growth factor (PDGF) on OPN mRNA expression was investigated in cultured rat aortic SMCs (RASMCs). When RASMCs were stimulated with 1 nmol/L PDGF, a 2.4-fold increase in OPN mRNA expression was observed at 3 hours (P < .05) that peaked at 14 hours with a 6.7-fold increase (P < .001). This induction was blocked by a monoclonal anti PDGF antibody. Further studies revealed that OPN mRNA expression was induced by PDGF-AB or PDGF-BB but not by PDGF-AA, indicating that only the beta-type PDGF receptor mediates this response. Compared with basic fibroblast growth factor, epidermal growth factor, transforming growth factor-beta, and interleukin-1 beta, PDGF was the most potent factor studied to induce OPN mRNA expression in RASMCs. Immunohistochemical studies demonstrated the elevation of OPN protein in PDGF-stimulated RASMCs. The temporal expression of OPN mRNA after rat carotid artery balloon angioplasty as assessed by both reverse transcription-polymerase chain reaction and Northern blot analysis revealed a 1.5-fold increase at 6 hours (P < .01) that peaked at 1 and 3 days with a 3.1-fold increase (P < .001). Immunohistochemical studies of carotid artery after angioplasty localized OPN expression in the medical SMCs at 1 day, ie. at a time of significant platelet adherence to the injured vessel, and thereafter to the intimal lesion during neointimal formation. These data suggest that OPN expression in vascular SMCs is regulated by PDGF through the beta-type PDGF receptor in vitro, and possibly in vivo in situations that involve PDGF released from platelets or other cellular sources, such as blood vessels after angioplasty injury.

Carvedilol prevents low-density lipoprotein (LDL)-enhanced monocyte adhesion to endothelial cells by inhibition of LDL oxidation

Cultured human umbilical vein endothelial cells oxidize low-density lipoproteins (LDL), assessed as increase in thiobarbituric acid reactive substance formation and oxidized LDL-induced cytotoxicity (lactate dehydrogenase (LDH) release). Endothelial cell-generated oxidized also enhances the adhesiveness of endothelial cells to monocytes. Carvedilol, a new vasodilating beta-adrenoceptor antagonist, inhibits the oxidation of LDL by endothelial cells and reduces oxidized LDL-induced LDH release from endothelial cells in a concentration-dependent manner with IC50 values of 2.56 and 1.38 microM, respectively. Moreover, carvedilol inhibits oxidized LDL-induced adhesion of monocytes to the endothelial cells in a similar concentration-dependent manner. Under the same conditions, propranolol, atenolol, pindolol and labetalol had only weak or no consistent effects on both LDL oxidation by endothelial cells and adhesion of monocytes to the endothelial cells. Monoclonal antibodies against human intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) or E-selectin (ELAM-1) partially blocked oxidized LDL-stimulated adhesion of endothelial cells to monocytes. The inhibitory effects of carvedilol on LDL oxidation and monocyte adhesion to endothelial cells may protect blood vessels from atherosclerotic processes associated with oxidized LDL-induced injuries.

Interleukin-1 beta regulates the expression of a leukocyte type of 12-lipoxygenase in rat islets and RIN m5F cells

The leukocyte type of 12-lipoxygenase (12-LO) may play a role in inflammatory reactions in many cell types through the conversion of arachidonic acid to proinflammatory eicosanoids that include 12-hydroperoxyeicosatetraenoic acid and 12-hydroeicosatetraenoic acid. Previous studies demonstrating the presence of a functional 12-LO pathway in rat and human pancreatic beta-cells plus the recent cloning of a rat leukocyte type of 12-LO allowed us to evaluate whether inflammatory cytokines such as interleukin-1 beta (IL-1 beta) can regulate the beta-cell 12-LO enzyme pathway, thus providing a potential link between the cytotoxic effects of cytokines on pancreatic beta-cells and the proinflammatory effects of 12-LO products. We demonstrate that IL-1 beta induces 12-LO protein and messenger RNA (mRNA) expression in RIN m5F cells and 12-LO mRNA expression in rat islets. RIN m5F cells treated for 16 h with IL-1 beta (25, 50, and 100 ng/liter) showed a maximal 2-fold increase in the expression of a leukocyte form of 12-LO demonstrated by Western blots. A concomitant increase in 12-LO mRNA expression was seen at this time point using a highly sensitive competitive polymerase chain reaction assay. The increase in mRNA and protein expression was preceded by increased 12-LO pathway activity measured by a RIA for 12-S-HETE. Separate experiments using purified Sprague-Dawley rat islets also showed increased expression of 12-LO mRNA and enzyme activity in response to IL-1 beta. These results demonstrate that IL-1 beta can up-regulate 12-LO expression and activity in rat beta-cells.

Magnesium supplementation reduces development of diabetes in a rat model of spontaneous NIDDM

We examined the effects of a magnesium-supplemented (Mg-S) diet in the male obese Zucker diabetic fatty rat, a model of non-insulin-dependent diabetes mellitus (NIDDM). Obese rats were maintained on either a control (0.20% Mg) or magnesium-supplemented (Mg-S; 1% Mg) diet for 6 wk beginning at 6 wk of age. The rats maintained on the Mg-S diet had markedly lower fasting and fed-state blood glucose concentrations and an improved glucose disposal. By 12 wk of age, all of the eight animals on the control diet became diabetic, whereas diabetes developed in only one of eight animals on the Mg-S diet. Insulin and C-peptide concentrations, in addition to pancreatic GLUT-2 and insulin mRNA expression, were higher in the male obese Mg-S rats than in their control-fed counterparts. A subgroup of rats on the control diet with established diabetes was switched to a Mg-S diet for an additional 4 wk. The Mg-S diet did not reverse diabetes once already established. These data indicate that an increased dietary Mg intake in male obese rats prevents deterioration of glucose tolerance, thus delaying the development of spontaneous NIDDM.