Cheuk-Kwan Sun

Intermittent Hypoxia Induces Hyperlipidemia in Lean Mice

Obstructive sleep apnea, a syndrome leading to recurrent intermittent hypoxia (IH), has been associated previously with hypercholesterolemia, independent of underlying obesity. We examined the effects of experimentally induced IH on serum lipid levels and pathways of lipid metabolism in the absence and presence of obesity. Lean C57BL/6J mice and leptin-deficient obese C57BL/6J-Lepob mice were exposed to IH for five days to determine changes in serum lipid profile, liver lipid content, and expression of key hepatic genes of lipid metabolism. In lean mice, exposure to IH increased fasting serum levels of total cholesterol, high-density lipoprotein (HDL) cholesterol, phospholipids (PLs), and triglycerides (TGs), as well as liver TG content. These changes were not observed in obese mice, which had hyperlipidemia and fatty liver at baseline. In lean mice, IH increased sterol regulatory element binding protein 1 (SREBP-1) levels in the liver, increased mRNA and protein levels of stearoyl–coenzyme A desaturase 1 (SCD-1), an important gene of TG and PL biosynthesis controlled by SREBP-1, and increased monounsaturated fatty acid content in serum, which indicated augmented SCD-1 activity. In addition, in lean mice, IH decreased protein levels of scavenger receptor B1, regulating uptake of cholesterol esters and HDL by the liver. We conclude that exposure to IH for five days increases serum cholesterol and PL levels, upregulates pathways of TG and PL biosynthesis, and inhibits pathways of cholesterol uptake in the liver in the lean state but does not exacerbate the pre-existing hyperlipidemia and metabolic disturbances in leptin-deficient obesity.

Early extracorporeal membrane oxygenator-assisted primary percutaneous coronary intervention improved 30-day clinical outcomes in patients with ST-segment elevation myocardial infarction complicated with profound cardiogenic shock

Objectives:This study tested the hypothesis that early extracorporeal membrane oxygenator offered additional benefits in improving 30-day outcomes in patients with acute ST-segment elevation myocardial infarction complicated with profound cardiogenic shock undergoing primary percutaneous coronary intervention. Methods:Between May 1993 and July 2002, 920 patients with acute ST-segment elevation myocardial infarction underwent primary percutaneous coronary intervention. Of these patients, 12.5% (115) with cardiogenic shock were enrolled in this study (group 1). Between August 2002 and December 2009, 1650 patients with acute ST-segment elevation myocardial infarction underwent primary percutaneous coronary intervention. Of these patients, 13.3% (219) complicated with cardiogenic shock were enrolled (group 2). Results:The incidence of profound shock (defined as systolic blood pressure remaining ≤75 mm Hg after intra-aortic balloon pump and inotropic agent supports) was similar in both groups (21.7% vs. 21.0%, p > .5). Extracorporeal membrane oxygenator support, which was available only for patients in group 2, was performed in the catheterization room. The results demonstrated that final thrombolysis in myocardial infarction grade 3 flow in infarct-related artery was similar between the two groups (p = .678). However, total 30-day mortality and the mortality of patients with profound shock were lower in group 2 than in group 1 (all p < .04). Additionally, the hospital survival time was remarkably longer in patients in group 2 than in patients in group 1 (p = .0005). Furthermore, multivariate analysis demonstrated that unsuccessful reperfusion, presence of advanced congestive heart failure, profound shock, and age were independent predictors of 30-day mortality (all p < .02). Conclusion:Early extracorporeal membrane oxygenator-assisted primary percutaneous coronary intervention improved 30-day outcomes in patients with ST-segment elevation myocardial infarction with complicated with profound cardiogenic shock.

Adipose-Derived Mesenchymal Stem Cell Protects Kidneys against Ischemia-Reperfusion Injury through Suppressing Oxidative Stress and Inflammatory Reaction

BackgroundReactive oxygen species are important mediators exerting toxic effects on various organs during ischemia-reperfusion (IR) injury. We hypothesized that adipose-derived mesenchymal stem cells (ADMSCs) protect the kidney against oxidative stress and inflammatory stimuli in rat during renal IR injury.MethodsAdult male Sprague-Dawley (SD) rats (n = 24) were equally randomized into group 1 (sham control), group 2 (IR plus culture medium only), and group 3 (IR plus immediate intra-renal administration of 1.0 × 106 autologous ADMSCs, followed by intravenous ADMSCs at 6 h and 24 h after IR). The duration of ischemia was 1 h, followed by 72 hours of reperfusion before the animals were sacrificed.ResultsSerum creatinine and blood urea nitrogen levels and the degree of histological abnormalities were markedly lower in group 3 than in group 2 (all p < 0.03). The mRNA expressions of inflammatory, oxidative stress, and apoptotic biomarkers were lower, whereas the anti-inflammatory, anti-oxidative, and anti-apoptotic biomarkers were higher in group 3 than in group 2 (all p < 0.03). Immunofluorescent staining showed a higher number of CD31+, von Willebrand Factor+, and heme oxygenase (HO)-1+ cells in group 3 than in group 2 (all p < 0.05). Western blot showed notably higher NAD(P)H quinone oxidoreductase 1 and HO-1 activities, two indicators of anti-oxidative capacity, in group 3 than those in group 2 (all p < 0.04). Immunohistochemical staining showed higher glutathione peroxidase and glutathione reductase activities in group 3 than in group 2 (all p < 0.02)ConclusionADMSC therapy minimized kidney damage after IR injury through suppressing oxidative stress and inflammatory response.

Adipose-derived mesenchymal stem cells markedly attenuate brain infarct size and improve neurological function in rats

BackgroundThe therapeutic effect of adipose-derived mesenchymal stem cells (ADMSCs) on brain infarction area (BIA) and neurological status in a rat model of acute ischemic stroke (IS) was investigated.MethodsAdult male Sprague-Dawley (SD) rats (n = 30) were divided into IS plus intra-venous 1 mL saline (at 0, 12 and 24 h after IS induction) (control group) and IS plus intra-venous ADMSCs (2.0 × 106) (treated interval as controls) (treatment group) after occlusion of distal left internal carotid artery. The rats were sacrificed and brain tissues were harvested on day 21 after the procedure.ResultsThe results showed that BIA was larger in control group than in treatment group (p < 0.001). The sensorimotor functional test (Corner test) identified a higher frequency of turning movement to left in control group than in treatment group (p < 0.05). mRNA expressions of Bax, caspase 3, interleukin (IL)-18, toll-like receptor-4 and plasminogen activator inhibitor-1 were higher, whereas Bcl-2 and IL-8/Gro were lower in control group than in treatment group (all p < 0.05). Western blot demonstrated a lower CXCR4 and stromal-cell derived factor-1 (SDF-1) in control group than in treatment group (all p < 0.01). Immunohistofluorescent staining showed lower expressions of CXCR4, SDF-1, von Willebran factor and doublecortin, whereas the number of apoptotic nuclei on TUNEL assay was higher in control group than in treatment group (all p < 0.001). Immunohistochemical staining showed that cellular proliferation and number of small vessels were lower but glial fibrillary acid protein was higher in control group than in treatment group (all p < 0.01).ConclusionsADMSC therapy significantly limited BIA and improved sensorimotor dysfunction after acute IS.

Effect of ischemia-reperfusion injury on the microcirculation of the steatotic liver of the Zucker rat.

BACKGROUND Much discussion has been focused on the use of steatotic livers for transplantation due to the prevalence of steatosis in the potential donor liver pool (1). The aim of this study was to investigate the possibility that the microcirculation of steatotic liver is more sensitive to the ischemia-reperfusion (IR) injury than normal liver. METHODS The left liver lobe of obese (n=9) and lean Zucker rats (n=9) were subjected to 40 min of warm ischemia followed by 60 min of reperfusion. Fluorescent probes rhodamine 123 (Rh123), bisbenzimide (Bis), and rhodamine 6G (Rh6G) were administered for the identification by intravital fluorescence microscopy (IVFM) of mitochondrial membrane potential, hepatocyte nuclei and leukocytes, respectively before hepatic ischemia and at 15, 30, 45, and 60 min after reperfusion. Blood samples were obtained before and after 60 min of reperfusion. Liver tissue was taken at the end of experiment for histological analysis. RESULTS The liver of the obese rats showed prominent macro- and microvesicular fatty changes (MAFC and MIFC) and hepatocyte swelling. Under IVFM, the obese animals had significantly wider hepatic cords (23.1+/-0.8 microm) than the lean ones (15.9+/-0.5 microm) (P<0.01), whereas no significant difference in sinusoidal diameters was noted. The number of functional sinusoids significantly decreased after 30 min of reperfusion in both groups but no significant change was noted in the nucleus count throughout the experiment. Rh123 fluorescence intensity dropped significantly in the obese group after 60 min of reperfusion but not in the lean rats. Leukocyte adherence showed a significant rise after reperfusion in both groups. Plasma AST and ALT levels were 40- and 24-fold higher respectively for the obese animals after IR compared with their preischemic values, whereas the corresponding increase were 4.2- and 3.4-fold for the lean animals, respectively. CONCLUSIONS Our results indicate that the liver of the obese Zucker rat is steatotic and presents with an abnormal microcirculation manifested by a reduced sinusoidal density. IR led to significantly greater hepatic injury in the steatotic than in the normal liver. This injury was accompanied by a significant reduction in the functional sinusoidal density and mitochondrial membrane potential as assessed by Rh123-associated fluorescence in the steatotic liver. In conclusion, the increased sensitivity of the steatotic liver to IR injury would appear to involve both alterations in blood flow in the microcirculation and to cellular changes.

Autologous Transplantation of Adipose-Derived Mesenchymal Stem Cells Markedly Reduced Acute Ischemia-Reperfusion Lung Injury in a Rodent Model

BackgroundThis study tested the hypothesis that autologous transplantation of adipose-derived mesenchymal stem cells (ADMSCs) can effectively attenuate acute pulmonary ischemia-reperfusion (IR) injury.MethodsAdult male Sprague-Dawley (SD) rats (n = 24) were equally randomized into group 1 (sham control), group 2 (IR plus culture medium only), and group 3 (IR plus intravenous transplantation of 1.5 × 106 autologous ADMSCs at 1h, 6h, and 24h following IR injury). The duration of ischemia was 30 minutes, followed by 72 hours of reperfusion prior to sacrificing the animals. Blood samples were collected and lungs were harvested for analysis.ResultsBlood gas analysis showed that oxygen saturation (%) was remarkably lower, whereas right ventricular systolic pressure was notably higher in group 2 than in group 3 (all p < 0.03). Histological scoring of lung parenchymal damage was notably higher in group 2 than in group 3 (all p < 0.001). Real time-PCR demonstrated remarkably higher expressions of oxidative stress, as well as inflammatory and apoptotic biomarkers in group 2 compared with group 3 (all p < 0.005). Western blot showed that vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, oxidative stress, tumor necrosis factor-α and nuclear factor-κB were remarkably higher, whereas NAD(P)H quinone oxidoreductase 1 and heme oxygenase-1 activities were lower in group 2 compared to those in group 3 (all p < 0.004). Immunofluorescent staining demonstrated notably higher number of CD68+ cells, but significantly fewer CD31+ and vWF+ cells in group 2 than in group 3.ConclusionADMSC therapy minimized lung damage after IR injury in a rodent model through suppressing oxidative stress and inflammatory reaction.

Melatonin treatment improves adipose-derived mesenchymal stem cell therapy for acute lung ischemia–reperfusion injury

This study investigated whether melatonin‐treated adipose‐derived mesenchymal stem cells (ADMSC) offered superior protection against acute lung ischemia–reperfusion (IR) injury. Adult male Sprague‐Dawley rats (n = 30) were randomized equally into five groups: sham controls, lung IR–saline, lung IR–melatonin, lung IR–melatonin–normal ADMSC, and lung IR–melatonin–apoptotic ADMSC. Arterial oxygen saturation was lowest in lung IR–saline; lower in lung IR–melatonin than sham controls, lung IR–melatonin–normal ADMSC, and lung IR–melatonin–apoptotic ADMSC; lower in lung IR–melatonin–normal ADMSC than sham controls and lung IR–melatonin–apoptotic ADMSC; lower in lung IR–melatonin–apoptotic ADMSC than sham controls (P < 0.0001 in each case). Right ventricular systolic blood pressure (RVSBP) showed a reversed pattern among all groups (all P < 0.0001). Changes in histological scoring of lung parenchymal damage and CD68+ cells showed a similar pattern compared with RVSBP in all groups (all P < 0.001). Changes in inflammatory protein expressions such as VCAM‐1, ICAM‐1, oxidative stress, TNF‐α, NF‐κB, PDGF, and angiotensin II receptor, and changes in apoptotic protein expressions of cleaved caspase 3 and PARP, and mitochondrial Bax, displayed identical patterns compared with RVSBP in all groups (all P < 0.001). Numbers of antioxidant (GR+, GPx+, NQO‐1+) and endothelial cell biomarkers (CD31+ and vWF+) were lower in sham controls, lung IR–saline, and lung IR–melatonin than lung IR–melatonin–normal ADMSC and lung IR–melatonin–apoptotic ADMSC, and lower in lung IR–melatonin–normal ADMSC than lung IR–melatonin–apoptotic ADMSC (P < 0.001 in each case). In conclusion, when the animals were treated with melatonin, the apoptotic ADMSC were superior to normal ADMSC for protection of lung from acute IR injury.

Effect of erythropoietin on level of circulating endothelial progenitor cells and outcome in patients after acute ischemic stroke

IntroductionErythropoietin (EPO) enhances the circulating level of endothelial progenitor cells (EPCs), which has been reported to be associated with prognostic outcome in ischemic stroke (IS) patients. The aim of this study was to evaluate the time course of circulating EPC level and the impact of EPO therapy on EPC level and clinical outcome in patients after acute IS.MethodsIn total, 167 patients were prospectively randomized to receive either EPO therapy (group 1) (5,000 IU each time, subcutaneously) at 48 h and 72 h after acute IS, or serve as placebo (group 2). The circulating level of EPCs (double-stained markers: CD31/CD34 (E1), CD62E/CD34 (E2) and KDR/CD34 (E3)) was determined using flow cytometry at 48 h and on days 7 and 21 after IS. EPC level was also evaluated once in 60 healthy volunteers.ResultsCirculating EPC (E1 to E3) level at 48 h after IS was remarkably higher in patients than in control subjects (P < 0.02). At 48 h and on Day 7 after IS, EPC (E1 to E3) level did not differ between groups 1 and 2 (all P > 0.1). However, by Day 21, EPC (E1 to E3) level was significantly higher in group 1 than in group 2 (all P < 0.03). Additionally, 90-day recurrent stroke rate was notably lower in group 1 compared with group 2 (P = 0.022). Multivariate analysis demonstrated that EPO therapy (95% confidence interval (CI), 0.153 to 0.730; P = 0.006) and EPC (E3) (95% CI, 0.341 to 0.997; P = 0.049) levels were significantly and independently predictive of a reduced 90-day major adverse neurological event (MANE) (defined as recurrent stroke, National Institutes of Health Stroke scale ≥8, or death).ConclusionsEPO therapy significantly improved circulating EPC level and 90-day MANE.Trial registration numberISRCTN: ISRCTN96340690

Propofol pretreatment attenuates LPS-induced granulocyte–macrophage colony-stimulating factor production in cultured hepatocytes by suppressing MAPK/ERK activity and NF-κB translocation

Propofol (PPF), a widely used intravenous anesthetic for induction and maintenance of anesthesia during surgeries, was found to possess suppressive effect on host immunity. This study aimed at investigating whether PPF plays a modulatory role in the lipopolysaccharide (LPS)-induced inflammatory cytokine expression in a cell line of rat hepatocytes. Morphological observation and viability assay showed that PPF exhibits no cytotoxicity at concentrations up to 300 microM after 48 h incubation. Pretreatment with 100 microM PPF for 24 h prior to LPS stimulation was performed to investigate the modulatory effect on LPS-induced inflammatory gene production. The results of semi-quantitative RT-PCR demonstrated that PPF pretreatment significantly suppressed the LPS-induced toll-like receptor (TLR)-4, CD14, tumor necrosis factor (TNF)-alpha, and granulocyte-macrophage colony-stimulating factor (GM-CSF) gene expression. Western blotting analysis showed that PPF pretreatment potentiated the LPS-induced TLR-4 downregulation. Flow cytometrical analysis revealed that PPF pretreatment showed no modulatory effect on the LPS-upregulated CD14 expression on hepatocytes. In addition, PPF pretreatment attenuated the phosphorylation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and IkappaBalpha, as well as the nuclear translocation of NF-kappaB primed by LPS. Moreover, addition of PD98059, a MAPK kinase inhibitor, significantly suppressed the LPS-induced NF-kappaB nuclear translocation and GM-CSF production, suggesting that the PPF-attenuated GM-CSF production in hepatocytes may be attributed to its suppressive effect on MAPK/ERK signaling pathway. In conclusion, PPF as an anesthetic may clinically benefit those patients who are vulnerable to sepsis by alleviating sepsis-related inflammatory response in livers.

Bone marrow-derived mononuclear cell therapy alleviates left ventricular remodeling and improves heart function in rat-dilated cardiomyopathy.

Objectives: This study hypothesized that bone marrow–derived mononuclear cell (BMDMNC) therapy may improve cardiac function through preventing cell death, alleviating left ventricular (LV) remodeling, and enhancing angio-/vasculo-genesis, as well as preserving LV contractility in a rat model of dilated cardiomyopathy (DCM). Design: A model of DCM in Sprague-Dawley rats was used to investigate the effects of BMDMNC therapy on inflammatory and oxidative response, energy depression, cellular apoptosis, expressions of protein kinase C-(PKC)-&egr;, and connexin43 protein (Cx43) in LV myocardium and heart function. Setting: An animal model research laboratory at Kaohsiung Chang Gung Memorial Hospital. Measurements: The rats were divided into group 1 (normal control, n = 8), group 2 (saline-treated DCM, n = 10), and group 3 (1.2 × 106 BMDMNC implanted into LV anterior wall on day 35 after DCM induction, n = 10). The DCM and normal control rats were killed on day 90 following DCM induction. Results: The results demonstrated that Cx43 protein expression and messenger RNA expressions of peroxisome proliferator-activated receptor-&ggr; coactivator 1 &agr;, endothelial nitric oxide synthase, and interleukin-10 were higher, whereas messenger RNA expressions of endothelin-1 and matrix metalloproteinase-9 were lower in groups 1 and 3 than in group 2 (all p < 0.05). Additionally, expressions of PKC-&egr; in plasma membrane and mitochondria and LV function were conserved in group 1 and improved in group 3, whereas cardiomyocyte apoptosis, mitochondrial oxidative stress, and fibrosis of LV myocardium were reduced in groups 1 and 3 than in group 2 (all p < 0.005). Conclusion: BMDMNC therapy in DCM significantly improves LV function by limiting cellular apoptosis, inflammatory and oxidative responses, and by up-regulating expressions of Cx43, PKC-&egr;, and energy transcription factors.