Po Len Liu

High Glucose Impairs Early and Late Endothelial Progenitor Cells by Modifying Nitric Oxide–Related but Not Oxidative Stress–Mediated Mechanisms

OBJECTIVE—Endothelial progenitor cells (EPCs) are impaired in diabetes. This study aimed to investigate the direct effects of high glucose on EPCs. RESEARCH DESIGN AND METHODS—Mononuclear cells isolated from healthy subjects were incubated with glucose/mannitol or drugs for EPC study. After 4 days of culture, attached early EPCs appeared. The monolayer late EPCs with cobblestone shape appeared at 2–4 weeks. Various immunofluroscence stainings were used to characterize the early and late EPCs. Senescence assay and the activity of endothelial nitric oxide synthase (eNOS) were determined. Migration and tube formation assay were done to evaluate the capacity for vasculogenesis in late EPCs. RESULTS—Chronic incubation with high glucose but not mannitol (osmotic control) dose-dependently reduced the number and proliferation of early and late EPCs, respectively. High glucose enhanced EPC senescence and impaired the migration and tube formation of late EPCs. High glucose also decreased eNOS, FoxO1, and Akt phosphorylation and bioavailable nitric oxide (NO) in both EPCs. The effects of high glucose could be ameliorated by coincubation with NO donor sodium nitroprusside or p38 mitogen–activated protein kinase inhibitor and deteriorated by eNOS inhibitor or PI3K (phosphatidylinositol 3′-kinase) inhibitor. Antioxidants including vitamin C, N-acetylcysteine–and polyethylene glycol (PEG)-conjugated superoxide dismutase, and PEG-catalase had no effects, whereas pyrrolidine dithiocarbamate, diphenyleneiodonium, apocynin, and rotenone even deteriorated the downregulation of both EPCs. CONCLUSIONS—High glucose impaired the proliferation and function of early and late EPCs. NO donor but not antioxidants reversed the impairments, suggesting the role of NO-related rather than oxidative stress–mediated mechanisms in hyperglycemia-caused EPC downregulation.

Resveratrol inhibits human lung adenocarcinoma cell metastasis by suppressing heme oxygenase 1‐mediated nuclear factor‐κB pathway and subsequently downregulating expression of matrix metalloproteinases

Resveratrol exhibits potential anti-carcinogenic activities. Heme oxygenase-1 (HO-1) is involved in angiogenesis and tumor metastasis. Matrix metalloproteinases (MMPs) are key enzymes in the degradation of extracellular matrix, and their expression may be dysregulated in lung cancer metastasis. In this study, we investigated the anti-invasive mechanism of resveratrol in lung cancer cells. HO-1 was shown to be elevated (approximately 4.7-fold) in lung cancer tumor samples as compared with matched normal tissues. After treatment of lung adenocarcinoma cell line A549 cells with resveratrol (50 microM) for 24 h, the migratory and invasive abilities (38 and 30% inhibition, respectively) of A549 cells were significantly reduced. Resveratrol significantly inhibited HO-1-mediated MMP-9 (35% inhibition) and MMP-2 (28% inhibition) expression in lung cancer cells. Nuclear factor (NF)-kappaB inhibitor induced a marked reduction in MMP-9 and MMP-2 expression, suggesting NF-kappaB pathway could play an important role. Furthermore, HO-1 inhibition and silencing significantly suppressed MMPs and invasion of lung cancer cells. Our results suggest that resveratrol inhibited HO-1 and subsequently MMP-9 and MMP-2 expression in lung cancer cells. The inhibitory effects of resveratrol on MMP expression and invasion of lung cancer cells are, in part, associated with the HO-1-mediated NF-kappaB pathway.

Antioxidative and hepatoprotective effects of magnolol on acetaminophen-induced liver damage in rats.

Acute liver failure (ALF), an often fatal condition characterized by massive hepatocyte necrosis, is frequently caused by drug poisoning, particularly with acetaminophen (N-acetyl-p-aminophenol/APAP). Hepatocyte necrosis is consecutive to glutathione (GSH) depletion and mitochondrial damage caused by reactive oxygen species (ROS) overproduction. Magnolol, one major phenolic constituent of Magnolia officinalis, have been known to exhibit potent antioxidative activity. In this study, the anti-hepatotoxic activity of magnolol on APAP-induced toxicity in the Sprague-Dawley rat liver was examined. After evaluating the changes of several biochemical parameters in serum, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) were elevated by APAP (500 mg/kg) intraperitoneal administration (8 and 24 h) and reduced by treatment with magnolol (0.5 h after APAP administration; 0.01, 0.1, and 1 μg/kg). Histological changes around the hepatic central vein, lipid peroxidation (thiobarbituric acid-reactive substance/TBARS), and GSH depletion in liver tissue induced by APAP were also recovered by magnolol treatment. The data show that oxidative stress followed by lipid peroxidation may play a very important role in the pathogenesis of APAP-induced hepatic injury; treatment with lipid-soluble antioxidant, magnolol, exerts anti-hepatotoxic activity. Our study points out the potential interest of magnolol in the treatment of toxic ALF.

Goniothalamin Inhibits Growth of Human Lung Cancer Cells through DNA Damage, Apoptosis, and Reduced Migration Ability

We evaluated the possible anticancer performance of a natural compound, goniothalamin (GTN), against human lung cancer using as a non-small cell lung cancer (NSCLC) cell line, H1299, as the model system. Cellular proliferation was significantly inhibited by GTN. Using an improved alkaline comet-nuclear extract (comet-NE) assay, GTN was found to induce a significant increase in the tail DNA. Wound healing and zymography assays showed that GTN attenuated cell migration and caused a reduction in the activity level of two major migration-associated matrix metalloproteinases, MMP-2 and MMP-9. It can be concluded that the DNA-damaging effect of GTN against lung cancer cells leads to growth inhibition as well as a depression in migration ability. Therefore, GTN has potential as a chemotherapeutic agent against lung cancer.

Endothelial progenitor cell dysfunction in cardiovascular diseases: Role of reactive oxygen species and inflammation

Endothelial progenitor cells (EPCs) move towards injured endothelium or inflamed tissues and incorporate into foci of neovascularisation, thereby improving blood flow and tissue repair. Patients with cardiovascular diseases have been shown to exhibit reduced EPC number and function. It has become increasingly apparent that these changes may be effected in response to enhanced oxidative stress, possibly as a result of systemic and localised inflammatory responses. The interplay between inflammation and oxidative stress affects the initiation, progression, and complications of cardiovascular diseases. Recent studies suggest that inflammation and oxidative stress modulate EPC bioactivity. Clinical medications with anti-inflammatory and antioxidant properties, such as statins, thiazolidinediones, angiotensin II receptor 1 blockers, and angiotensin-converting enzyme inhibitors, are currently administered to patients with cardiovascular diseases. These medications appear to exert beneficial effects on EPC biology. This review focuses on EPC biology and explores the links between oxidative stress, inflammation, and development of cardiovascular diseases.

High-Mobility Group Box 1―Mediated Matrix Metalloproteinase-9 Expression in Non―Small Cell Lung Cancer Contributes to Tumor Cell Invasiveness

High-mobility group box 1 (HMGB1) is a versatile protein with intranuclear and extracellular functions. It is involved in invasion and metastasis in various human malignancies. However, the role of HMGB1 in non-small cell lung cancer (NSCLC) is unclear. We hypothesized that HMGB1 expression is a determinant of cellular invasiveness and metastasis in lung cancer. We examined HMGB1 expression in 48 NSCLC specimens by quantitative real-time PCR. High HMGB1 expression was significantly associated with clinically advanced stages (stage III-IV) (P < 0.05) and was correlated to expression of matrix metalloproteinase-9 (MMP-9) (P < 0.05). Patients with high levels of HMGB1 expression had poorer clinical prognosis. The expression level of MMP-9 and metastatic ability in vitro were significantly higher in an HMGB1-overexpressing human NSCLC cell lines (A549 and H23). The treatment with HMGB1 small interfering RNA reduced MMP-9 expression and the cellular metastatic ability in NSCLC cells. We also demonstrated that phosphoinositide 3-kinase/Akt and NF-κB-related pathways contributed to the HMGB1-induced MMP-9 expression and cellular metastatic ability.

Identification of melamine/cyanuric acid-containing nephrolithiasis by infrared spectroscopy.

Melamine‐contaminated milk formula caused infant nephrolithiasis in some areas of China. Its combination with cyanuric acid causes crystallization in renal tubules. Following this renal damage and even renal failure that require long‐term hemodialysis has been reported. Therefore, correct and timely diagnosis of these complex diseases is critical. Melamine containing stone is a combination of equal molar ratios of common stone compositions that has been reported from previous animal studies. We have previously identified the compositions of urinary tract stones with infrared (IR) spectroscopy. We hypothesized that the absorbance of wavelength of IR can identify melamine/cyanuric acid in the presence of mixing human stone compositions. In this study, we made an artificial stone composition and examine under IR absorbance by mixing equal molar ratios of melamine/cyanuric acid with different types of human urinary stones, and established a reference of IR analysis for the identification of melamine/cyanuric acid‐containing human urinary tract stones. Knowledge of the precise stone composition allowed institution of appropriate prophylactic dietary and medical therapy and this may help in the prevention of urinary stone recurrence. The results are promising that melamine and cyanuric acid can be identified clearly in a low percentile (∼1%) of stone mixture pellet. Therefore, IR seems to be an ideal tool for the identification of melamine/cyanuric acid‐containing stones. J. Clin. Lab. Anal. 24:92–99, 2010.

Applications of Meridian Electrical Conductance for Renal Colic: A Prospective Study

OBJECTIVEnRenal colic caused by ureteral stone is commonly encountered in the emergency department (ED). This study was designed to measure meridian electrical conductance of patients with ureteral stone in emergency settings.nnnDESIGNnA cohort of patients who had ureteral calculus and acute renal colic and who had visited the ED was enrolled in this study. A device, the design of which is based on the Ryodoraku theory, was used to measure the meridian electrical conductance of patients in the ED. Sixty (60) patients (aged 42.0 +/- 12.6 years) who had a primary ED diagnosis of ureteral calculus or renal colic were enrolled. Thirty (30) healthy volunteers (aged 40.8 +/- 11.7 years) were recruited to serve as controls.nnnRESULTSnStatistical analysis showed that (1) the average electrical conductance of the patient group was statistically lower than that of the control group (p < 0.01), (2) the average index of sympathovagal balance of the patient group was statistically higher than that of the control group (p < 0.01), (3) the average coefficient of variation of the electrical conductance and index of sympathovagal balance in the patient group was statistically different from that in the control group (p < 0.01), and (4) the patients who needed intervention had a higher autonomic nervous imbalance than the patients who had spontaneous stone passage (p < 0.01).nnnCONCLUSIONSnMeasures of electrical conductance, especially the index of sympathovagal balance, may be used as valuable supplementary diagnostic methods for selective intervention in patients with acute renal colic.

Ginkgo biloba extract suppresses endotoxin-mediated monocyte activation by inhibiting nitric oxide- and tristetraprolin-mediated toll-like receptor 4 expression

Monocytes expressing toll-like receptor 4 (TLR4) play a major role in regulating the innate immune response and are involved in systemic inflammation. Previous studies have shown that Ginkgo biloba extract (GBE) may act as a therapeutic agent for some cardiovascular and neurological disorders. The objective of this study was to determine whether GBE could modulate immunity in human cells. The monocytic cell line THP-1 was used. Enzyme-linked immunosorbent assay results showed that lipopolysaccharide (LPS) induces the expression of monocyte chemotactic protein-1 (MIP-1), tumor necrosis factor-α, stromal cell-derived factor-1, and MIP-1α, and this induction may be repressed by GBE treatment due to TLR4 blockade. The Griess reagent assay and western blot analysis showed that GBE-mediated inhibition of TLR4 expression was associated with the activation of mitogen-activated protein kinase and production of nitric oxide (NO). Actinomycin D chase experiments demonstrated that GBE decreased the TLR4 mRNA stability in cells. Confocal microscopy and real-time polymerase chain reaction showed that GBE induced the expression of intracellular tristetraprolin (TTP). Transfection with TTP siRNA reversed the effects of GBE in naïve or TLR4-overexpressing cells. Treatment with SNAP (an NO donor) may increase intracellular TTP expression in cells. Immunoprecipitation analysis showed that GBE mediates TTP activation and increases the interaction of TTP with the 3 untranslated region (UTR) of TLR4 mRNA by regulating NO production. Our findings indicate that GBE could decrease the sensitivity of monocytes to LPS. Utilizing TTP to control TLR4 expression may be a promising approach for controlling systemic inflammation, and GBE may have potential applications in the clinical treatment of immune diseases.

Association of interleukin-18 gene polymorphisms with calcium oxalate kidney stone disease

Abstract Objective. The interleukin-18 (IL-18) encoding gene has three common single-nucleotide polymorphisms at –607C/A, –137G/C and +105A/C, which have been reported to be associated with several diseases. The aim of this study is to test whether IL-18 polymorphisms could act as genetic markers for renal stone disease. Material and methods. A control group of 104 healthy subjects, and 272 patients with recurrent calcium oxalate stones were examined. Polymerase chain reaction-based restriction endonuclease analysis was used to detect IL-18 polymorphisms. Results. The patient and control groups differed significantly in genotypic expression of the IL-18 +105A/C polymorphism. The prevalence of the A/C + C/C genotypes in the patients was higher than that in the controls. The allelic frequency of IL-18 +105A/C differed significantly between the patients and the controls. The odds ratio (OR) of the A/C heterozygote of IL-18 +105A/C associated with urolithiasis was 2.772. The OR of the A/C + C/C genotypes of IL-18 +105A/C associated with urolithiasis was 3.097. The OR per copy of the C allele of IL-18 +105A/C associated with urolithiasis was 4.143. There were also significant differences in the prevalence of genotype IL-18 –137G/C polymorphisms between the patients and controls. The distribution of the G/G homozygote in the patients was higher than that in the controls. There was no significant difference in genotype and allelic frequency at the IL-18 –607C/A polymorphism between patients and control subjects. Conclusion. The results indicate that IL-18 +105A/C polymorphisms may play a role in the development of urolithiasis.