JeongIl Kwon

Blue light emitting diode induces apoptosis in lymphoid cells by stimulating autophagy.

The present study was performed to examine the induction of apoptotic cell death and autophagy by blue LED irradiation, and the contribution of autophagy to apoptosis in B cell lymphoma A20 and RAMOS cells exposed to blue LED. Irradiation with blue LED reduced cell viability and induced apoptotic cell death, as indicated by exposure of phosphatidylserine on the plasma outside membrane and fragmentation of DNA. Furthermore, the mitochondrial membrane potential increased, and apoptotic proteins (PARP, caspase 3, Bax, and bcl-2) were observed. In addition, the level of intracellular superoxide anion (O2(-)) gradually increased. Interestingly the formation of autophagosomes and level of LC3-II were increased in blue LED-irradiated A20 and RAMOS cells, but inhibited after pretreatment with 3-methyladenine (3-MA), widely used as an autophagy inhibitor. Inhibition of the autophagic process by pretreatment with 3-MA blocked blue LED irradiation-induced caspase-3 activation. Moreover, a significant reduction of both the early and late phases of apoptosis after transfection with ATG5 and beclin 1 siRNAs was shown by the annexin V/PI staining, indicating a crucial role of autophagy in blue LED-induced apoptosis in cells. Additionally, the survival rate of mice irradiated with blue LED after injection with A20 cells increased compared to the control group. Our data demonstrate that blue LED irradiation induces apoptosis via the mitochondrial-mediated pathway, in conjunction with autophagy. Further studies are needed to elucidate the precise mechanism of blue LED-induced immune cell death.

Improving Cerebral Blood Flow through Liposomal Delivery of Angiogenic Peptides: Potential of 18F-FDG PET Imaging in Ischemic Stroke Treatment

Strategies to promote angiogenesis can benefit cerebral ischemia. We determined whether liposomal delivery of angiogenic peptides with a known biologic activity of vascular endothelial growth factor benefitted cerebral ischemia. Also, the study examined the potential of 18F-FDG PET imaging in ischemic stroke treatment. Methods: Male Sprague–Dawley rats (n = 40) underwent 40 min of middle cerebral artery occlusion. After 15 min of reperfusion, the rats (n = 10) received angiogenic peptides incorporated into liposomes. Animals receiving phosphate-buffered solution or liposomes without peptides served as controls. One week later, 18F-FDG PET imaging was performed to examine regional changes in glucose utilization in response to the angiogenic therapy. The following day, 99mTc-hexamethylpropyleneamine oxime autoradiography was performed to determine changes in cerebral perfusion after angiogenic therapy. Corresponding changes in angiogenic markers, including von Willebrand factor and angiopoietin-1 and -2, were determined by immunostaining and polymerase chain reaction analysis, respectively. Results: A 40-min period of middle cerebral artery occlusion decreased blood perfusion in the ipsilateral ischemic cortex of the brain, compared with that in the contralateral cortex, as measured by 99mTc-hexamethylpropyleneamine oxime autoradiography. Liposomal delivery of angiogenic peptides to the ischemic hemisphere of the brain attenuated the cerebral perfusion defect compared with controls. Similarly, vascular density evidenced by von Willebrand factor–positive staining was increased in response to angiogenic therapy, compared with that of controls. This increase was accompanied by an early increase in angiopoietin-2 expression, a gene participating in angiogenesis. 18F-FDG PET imaging measured at 7 d after treatment revealed that liposomal delivery of angiogenic peptides facilitated glucose utilization in the ipsilateral ischemic cortex of the brain, compared with that in the controls. Furthermore, the change in regional glucose utilization was correlated with the extent of improvement in cerebral perfusion (r = 0.742, P = 0.035). Conclusion: Liposomal delivery of angiogenic peptides benefits cerebral ischemia. 18F-FDG PET imaging holds promise as an indicator of the effectiveness of angiogenic therapy in cerebral ischemia.

Effect of Angiogenesis Induced by Consecutive Intramuscular Injections of Vascular Endothelial Growth Factor in a Hindlimb Ischemic Mouse Model

PurposeAngiogenesis plays a major role in various physiological and pathological situations. Thus, an angiogenic therapy with vascular endothelial growth factor (VEGF) has been commonly recommended as a representative therapeutic solution to recover the insufficient blood supply of collateral vessels in an ischemic lesion. In this study, the injection method and injection time point of VEGF proteins were focused to discover how to enhance the angiogenic effect with VEGF.MethodsMouse models (n = 15) were divided into control, VEGF treatment by intra-venous injection (VEGF-IV) and VEGF treatment by intra-muscular injection (VEGF-IM). Right proximal femoral arteries of mice were firmly sutured to obstruct arterial blood-flow. In the VEGF-IV treatment group, VEGF proteins were injected into the tail vein and, in the VEGF-IM treatment group, VEGF proteins were directly injected into the ischemic site of the right thigh after postoperative day 5, 10, 15, 20 and 25 follow-ups. Blood-flow images were acquired by 99mTc Gamma Image Acquisition System to compare the ischemic-to-non-ischemic bloodstream ratio at postoperative days 5, 15, and 30.ResultsVEGF-IM treatment significantly induced higher an angiogenic effect rather than both the control group (P = 0.008) and VEGF-IV treatment group (P = 0.039) at the 30th day.ConclusionDuring all experiments, angiogenesis of VEGF-IM treatment represented the most evident effect compared with control and VEGF-IV group in a mouse model of hindlimb ischemia.

131I-labeled chitosan hydrogels for radioembolization: A preclinical study in small animals

INTRODUCTION The purpose of the study was to examine potential of 131I-labeled chitosan hydrogels (Chi) for treatment of liver cancer. METHODS Orthotopic hepatoma was induced by McA-RH7777-fLuc cells (1×107) that were injected into the left hepatic lobe of rats. Ten days later, tumor-bearing rats evidenced by bioluminescence received 125I-labeled Chi with left hepatic artery access. Pharmacokinetics and excretion (n=8) and biodistribution (n=6/time point) were studied after injection. To examine therapeutic potential, animals (n=8/group) were also treated with Chi labeled with or without 131I. Changes in tumor volume by magnetic resonance (MR) imaging were studied. RESULTS The rate of tumor induction assessed by bioluminescence imaging was 72% (68/95). Gamma counter and scintigraphy imaging analyses showed accumulation of 125I-labeled Chi dominantly in the liver. A small fraction of 125I-labeled Chi was detected in the stomach (2.02±3.07%ID) and muscle (1.37±1.48%ID) at 2 d post-treatment. Blood sample analysis showed the maximum blood concentration of 0.09±0.03%ID/mL, which peaked at 0.60±0.45 d. Over a 4-week period, 31.22±8.16%ID were excreted in the urine and 3.5±1.3% in the feces. Treatment of Chi (median, 876mm3; IQR, 496mm3-1413mm3) markedly reduced the extent of tumor growth, compared to controls (median, 12,085mm3; IQR, 7786mm3-25,832mm3; P<0.05 vs control). 131I Chi (median, 80mm3; IQR, 35mm3-172mm3; P<0.05 vs control) induced a greater tumor-suppressing effect, compared to Chi alone. CONCLUSIONS In this study, we have characterized a new radioembolization device, 131I Chi, in vivo and provided evidence for its therapeutic potential. ADVANCES IN KNOWLEDGE Transarterial embolization is a conceivable treatment option for patients with inoperable liver cancer to mitigate the disease progression. Recently, we have developed chitosan-based hydrogel microparticles. In the present study, the hydrogel microparticles were radiolabeled with 131I for treatment of liver cancer. Our results demonstrated that a hepatic arterial injection of 125I-labeled Chi resulted in substantial liver accumulation, which was accompanied by virtually no extrahepatic deposition. The results of the present study also showed that administration of 131I Chi markedly suppressed tumor growth, compared to controls and to animals receiving unlabeled Chi. 131I-labeled chitosan hydrogel microparticles represent a new therapeutic approach for treatment of liver cancer.

PEGylated nanoliposomes encapsulating angiogenic peptides improve perfusion defects: Radionuclide imaging-based study

INTRODUCTION Although liposomes hold promise for cancer therapy, the effectiveness of treating myocardial ischemia by promoting angiogenesis has yet to be proved. Nanoliposomes loaded with therapeutic agents can effectively target ischemic myocardium via enhanced permeability and retention. Surface polyethylene glycol (PEG) modification can further facilitate effective targeting by prolonging liposomal circulation. This study aimed to determine whether PEGylated nanoliposomes are effective in facilitating targeted drug delivery and treating myocardial ischemia. METHODS Rats subjected to 30min of myocardial ischemia were given (99m)Tc-hexamethylpropyleneamine oxime- or (99m)Tc-diethylenetriamine pentaacetate-labeled liposomes with mean diameters of ~100nm or ~600nm with or without PEG modifications to determine the extent of myocardial uptake in the different conditions. Therapeutic effectiveness was assessed by studying changes in myocardial perfusion defects with (99m)Tc-tetrofosmin autoradiography and vascular density with immunohistochemistry at 7days post-treatment. RESULTS The liver and spleen showed the largest capacity for liposome uptake. Uptake by the liver and spleen was more pronounced when the liposomes were larger. Conversely, myocardial liposome uptake was significantly greater when the liposomes were ~100nm rather than ~600nm in diameter. Surface modification with PEG significantly augmented myocardial uptake of ~100nm liposomes. PEG modification did not affect the size dependence. To investigate therapeutic efficacy, hearts subjected to ischemia received PEGylated nanoliposomes encapsulated with angiogenic peptides. Our data demonstrated that PEGylated nanoliposomes loaded with angiogenic peptides improved myocardial perfusion defects and increased vascular density. A 10-fold increase in liposomal concentration did not further benefit myocardial ischemia. CONCLUSIONS Liposomal angiogenic formulation with size control and PEG modification may be effective treatment strategy for myocardial ischemia. Increasing the concentration of liposomes does not necessarily benefit myocardial ischemia.

Data in support of effect of blue LED irradiation in human lymphoma cells.

As a new and preferred light source for phototherapy, blue light emitting diodes (LEDs) with wavelengths of 400–500 nm have been used to treat hyperbilirubinaemia in infantile jaundice [1]. Recent studies report that blue LED irradiation induces apoptosis by stimulating a mitochondrial pathway and reduces the early growth rate of melanoma cells in mice [2]. Here, we detected the induction of apoptotic cell death and formation of autophagosome in human B lymphoma cells after irradiation with blue LED. This paper provides data in support of the research article entitled “Blue light emitting diode induces apoptosis in lymphoid cells by stimulating autophagy” [3].

Scintigraphic evaluation of therapeutic angiogenesis induced by VEGF-loaded chitosan nanoparticles in a rodent model of hindlimb ischemia

We examined the therapeutic effect of chitosan nanoparticles (CHI) incorporating vascular endothelial growth factor (VEGF) on hindlimb ischemia using single photon emission computed tomography (SPECT) perfusion imaging. Rats (n=24) were divided randomly into four groups of six: control, VEGF, CHI, and CHI incorporated with VEGF (CHI-VEGF). The right femoral artery was ligated to block blood flow, and SPECT perfusion images were obtained every week for 4 weeks. The morphology of the synthesized CHI was identified as a spherical shape with an even size distribution (range, 93–250 nm). The VEGF loading efficiency in CHI was 8.6±2.1%. Upon injection into the femoral artery, 17.6±8.2% of the 99mTc-labeled CHI-VEGF administered remained in the ischemic lesion. The restoration of blood flow (ratio of ischemia to normal) measured by SPECT perfusion imaging was greater in animals treated with CHI-VEGF compared to that in the control (p=0.028), VEGF (p=0.010), and CHI (p=0.011) groups. Administering CHI-VEGF had a significant therapeutic effect in a hindlimb ischemic rat model. 99mTc gamma perfusion imaging was useful to study therapeutic angiogenesis.