Potential Risk of Choline Alfoscerate on Isoflurane-Induced Toxicity in Primary Human Astrocytes

Objective

Isoflurane, a widely used common inhalational anesthetic agent, can induce brain toxicity. The challenge lies in protecting neurologically compromised patients from neurotoxic anesthetics. Choline alfoscerate (L-α-Glycerophosphorylcholine, α-GPC) is recognized for its neuroprotective properties against oxidative stress and inflammation, but its optimal therapeutic window and indications are still under investigation. This study explores the impact of α-GPC on human astrocytes, the most abundant cells in the brain that protect against oxidative stress, under isoflurane exposure.

Methods

This study was designed to examine changes in factors related to isoflurane-induced toxicity following α-GPC administration. Primary human astrocytes were pretreated with varying doses of α-GPC (ranging from 0.1 to 10.0 μM) for 24 hours prior to 2.5% isoflurane exposure. In vitro analysis of cell morphology, water-soluble tetrazolium salt-1 assay, quantitative real-time polymerase chain reaction, proteome profiler array, and transcriptome sequencing were conducted.

Results

A significant morphological damage to human astrocytes was observed in the group that had been pretreated with 10.0 mM of α-GPC and exposed to 2.5% isoflurane. A decrease in cell viability was identified in the group pretreated with 10.0 μM of α-GPC and exposed to 2.5% isoflurane compared to the group exposed only to 2.5% isoflurane. Quantitative real-time polymerase chain reaction revealed that mRNA expression of heme-oxygenase 1 and hypoxia-inducible factor-1α, which were reduced by isoflurane, was further suppressed by 10.0 μM α-GPC pretreatment. The proteome profiler array demonstrated that α-GPC pretreatment influenced a variety of factors associated with apoptosis induced by oxidative stress. Additionally, transcriptome sequencing identified pathways significantly related to changes in isoflurane-induced toxicity caused by α-GPC pretreatment.

Conclusion

The findings suggest that α-GPC pretreatment could potentially enhance the vulnerability of primary human astrocytes to isoflurane-induced toxicity by diminishing the expression of antioxidant factors, potentially leading to amplified cell damage.

Penetrative and Sustained Drug Delivery Using Injectable Hydrogel Nanocomposites for Postsurgical Brain Tumor Treatment

Postsurgical treatment of glioblastoma multiforme (GBM) by systemic chemotherapy and radiotherapy is often inefficient. Tumor cells infiltrating deeply into the brain parenchyma are significant obstacles to the eradication of GBM. Here, we present a potential solution to this challenge by introducing an injectable thermoresponsive hydrogel nanocomposite. As a liquid solution that contains drug-loaded micelles and water-dispersible ferrimagnetic iron oxide nanocubes (wFIONs), the hydrogel nanocomposite is injected into the resected tumor site after surgery. It promptly gelates at body temperature to serve as a soft, deep intracortical drug reservoir. The drug-loaded micelles target residual GBM cells and deliver drugs with a minimum premature release. Alternating magnetic fields accelerate diffusion through heat generation from wFIONs, enabling penetrative drug delivery. Significantly suppressed tumor growth and improved survival rates are demonstrated in an orthotopic mouse GBM model. Our system proves the potential of the hydrogel nanocomposite platform for postsurgical GBM treatment.

Multiparametric magnetic resonance imaging features of a canine glioblastoma model

PURPOSE

To assess glioblastoma multiforme (GBM) formation with similar imaging characteristics to human GBM using multiparametric magnetic resonance imaging (MRI) in an orthotopic xenograft canine GBM model.

MATERIALS AND METHODS

The canine GBM cell line J3T1 was subcutaneously injected into 6-week-old female BALB/c nude mice to obtain tumour fragments. Tumour fragments were implanted into adult male mongrel dog brains through surgery. Multiparametric MRI was performed with conventional MRI, diffusion-weighted imaging, and dynamic susceptibility contrast-enhanced perfusion-weighted imaging at one week and two weeks after surgery in a total of 15 surgical success cases. The presence of tumour cells, the necrotic area fraction, and the microvessel density (MVD) of the tumour on the histologic specimen were assessed. Tumour volume, diffusion, and perfusion parameters were compared at each time point using Wilcoxon signed-rank tests, and the differences between tumour and normal parenchyma were compared using unpaired t-tests. Spearman correlation analysis was performed between the imaging and histologic parameters.

RESULTS

All animals showed a peripheral enhancing lesion on MRI and confirmed the presence of a tumour through histologic analysis (92.3%). The normalized perfusion values did not show significant decreases through at least 2 weeks after the surgery (P > 0.05). There was greater cerebral blood volume and flow in the GBM than in the normal-appearing white matter (1.46 ± 0.25 vs. 1.13 ± 0.16 and 1.30 ± 0.22 vs. 1.02 ± 0.14; P < 0.001 and P < 0.001, respectively). The MVD in the histologic specimens was correlated with the cerebral blood volume in the GBM tissue (r = 0.850, P = 0.004).

CONCLUSION

Our results suggest that the canine GBM model showed perfusion imaging characteristics similar to those of humans, and it might have potential as a model to assess novel technical developments for GBM treatment.

Localized Delivery of Theranostic Nanoparticles and High-Energy Photons using Microneedles-on-Bioelectronics

The low delivery efficiency of light-responsive theranostic nanoparticles (NPs) to target tumor sites, particularly to brain tumors due to the blood-brain barrier, has been a critical issue in NP-based cancer treatments. Furthermore, high-energy photons that can effectively activate theranostic NPs are hardly delivered to the target region due to the strong scattering of such photons while penetrating surrounding tissues. Here, a localized delivery method of theranostic NPs and high-energy photons to the target tumor using microneedles-on-bioelectronics is presented. Two types of microneedles and flexible bioelectronics are integrated and mounted on the edge of surgical forceps. Bioresorbable microneedles containing theranostic NPs deliver the NPs into target tumors (e.g., glioblastoma, pituitary adenoma). Magnetic resonance imaging can locate the NPs. Then, light-guiding/spreading microneedles deliver high-energy photons from bioelectronics to the NPs. The high-energy photons activate the NPs to treat tumor tissues by photodynamic therapy and chemotherapy. The controlled thermal actuation by the bioelectronics accelerates the diffusion of chemo-drugs. The proposed method is demonstrated with mouse tumor models in vivo.

Radiogenomics Profiling for Glioblastoma-related Immune Cells Reveals CD49d Expression Correlation with MRI parameters and Prognosis

Although there have been a plethora of radiogenomics studies related to glioblastoma (GBM), most of them only used genomic information from tumor cells. In this study, we used radiogenomics profiling to identify MRI-associated immune cell markers in GBM, which was also correlated with prognosis. Expression levels of immune cell markers were correlated with quantitative MRI parameters in a total of 60 GBM patients. Fourteen immune cell markers (i.e., CD11b, CD68, CSF1R, CD163, CD33, CD123, CD83, CD63, CD49d and CD117 for myeloid cells, and CD4, CD3e, CD25 and CD8 for lymphoid cells) were selected for RNA-level analysis using quantitative RT-PCR. For MRI analysis, quantitative MRI parameters from FLAIR, contrast-enhanced (CE) T1WI, dynamic susceptibility contrast perfusion MRI and diffusion-weighted images were used. In addition, PFS associated with interesting mRNA data was performed by Kaplan-Meier survival analysis. CD163, which marks tumor associated microglia/macrophages (TAMs), showed the highest expression level in GBM patients. CD68 (TAMs), CSF1R (TAMs), CD33 (myeloid-derived suppressor cell) and CD4 (helper T cell, regulatory T cell) levels were highly positively correlated with nCBV values, while CD3e (helper T cell, cytotoxic T cell) and CD49d showed a significantly negative correlation with apparent diffusion coefficient (ADC) values. Moreover, regardless of any other molecular characteristics, CD49d was revealed as one independent factor for PFS of GBM patients by Cox proportional-hazards regression analysis (P = 0.0002). CD49d expression level CD49d correlated with ADC can be considered as a candidate biomarker to predict progression of GBM patients.

Modified Rat Hepatocellular Carcinoma Models Overexpressing Vascular Endothelial Growth Factor

PURPOSE

To compare tumor vascularity in 4 types of rat hepatocellular carcinoma (HCC) models: N1S1, vascular endothelial growth factor (VEGF)-transfected N1S1 (VEGF-N1S1), McA-RH7777, and VEGF-transfected McA-RH7777 (VEGF-McA-RH777) tumors.

MATERIALS AND METHODS

The N1S1 and McA-RH7777 cell lines were transfected with expression vectors containing cDNA for rat VEGF. Eighty-eight male Sprague-Dawley rats (weight range, 400-450 g) were randomly divided into 4 groups (ie, 22 rats per model), and 4 types of tumor models were created by using the N1S1, VEGF-N1S1, McA-RH7777, and VEGF-McA-RH777 cell lines. Tumor vascularity was evaluated by perfusion computed tomography (CT), enzyme-linked immunosorbent assay of VEGF, CD34 staining, angiography, and Lipiodol transarterial embolization. Intergroup discrepancies were evaluated by Kruskal-Wallis test.

RESULTS

Arterial perfusion (P < .001), portal perfusion (P = .015), total perfusion (P < .001), tumor VEGF level (P = .002), and microvessel density (MVD; P = .007) were significantly different among groups. VEGF-McA-RH7777 tumors showed the greatest arterial perfusion (46.7 mL/min/100 mL ± 15.5), total perfusion (60.7 mL/min/100 mL ± 21.8), tumor VEGF level (3,376.7 pg/mL ± 145.8), and MVD (34.5‰ ± 7.5). Whereas most tumors in the N1S1, VEGF-N1S1, and McA-RH7777 groups showed hypovascular staining on angiography and minimal Lipiodol uptake after embolization, 5 of 6 VEGF-McA-RH7777 tumors (83.3%) presented hypervascular tumor staining and moderate to compact Lipiodol uptake.

CONCLUSIONS

McA-RH7777 tumors were more hypervascular than N1S1 tumors, and tumor vascularity was enhanced further by VEGF transfection. Therefore, the VEGF-McA-RH7777 tumor is recommended to mimic hypervascular human HCC in rats.

Glutaminase 2 expression is associated with regional heterogeneity of 5-aminolevulinic acid fluorescence in glioblastoma

Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) is now a widely-used modality for glioblastoma (GBM) treatment. However, intratumoral heterogeneity of fluorescence intensity may reflect different onco-metabolic programs. Here, we investigated the metabolic mechanism underlying the heterogeneity of 5-ALA fluorescence in GBM. Using an in-house developed fluorescence quantification system for tumor tissues, we collected 3 types of GBM tissues on the basis of their fluorescence intensity, which was characterized as strong, weak, and none. Expression profiling by RNA-sequencing revealed 77 genes with a proportional relationship and 509 genes with an inverse relationship between gene expression and fluorescence intensity. Functional analysis and in vitro experiments confirmed glutaminase 2 (GLS2) as a key gene associated with the fluorescence heterogeneity. Subsequent metabolite profiling discovered that insufficient NADPH due to GLS2 underexpression was responsible for the delayed metabolism of 5-ALA and accumulation of protoporphyrin IX (PpIX) in the high fluorescence area. The expression level of GLS2 and related NADPH production capacity is associated with the regional heterogeneity of 5-ALA fluorescence in GBM.

Sorafenib and 2,3,5-triiodobenzoic acid-loaded imageable microspheres for transarterial embolization of a liver tumor

Sorafenib (SOF; an angiogenesis inhibitor) and 2,3,5-triiodobenzoic acid (TIBA; a contrast agent for computed tomography imaging)-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres (MSs) were fabricated. Embolization, drug delivery, and tracing the distribution of MSs for liver cancer therapy were accomplished with the developed MSs after their intra-arterial (IA) administration. SOF/TIBA/PLGA MSs with 24.8–28.5 µm mean diameters were prepared, and the sustained release of SOF from MSs was observed. Lower systemic exposure (represented as the area under the curve [AUC]) and maximum drug concentration in plasma (C_max) values of the SOF/TIBA/PLGA MSs group (IA administration, 1 mg/kg) in the results of the pharmacokinetic study imply alleviated unwanted systemic effects (e.g., hand and foot syndrome), compared to the SOF solution group (oral administration, 10 mg/kg). In a rat hepatoma model, the increase of microvessel density (MVD) following arterial embolization (i.e., reactive angiogenesis) was partially limited by SOF/TIBA/PLGA MSs. This resulted in the SOF/TIBA/PLGA MSs group (IA administration, single dosing, 1 mg/kg) showing a smaller tumor size increase and viable tumor portion compared to the TIBA/PLGA MSs group. These findings suggest that a developed SOF/TIBA/PLGA MS can be a promising therapeutic system for liver cancer using a transarterial embolization strategy.

Wearable/disposable sweat-based glucose monitoring device with multistage transdermal drug delivery module

Electrochemical analysis of sweat using soft bioelectronics on human skin provides a new route for noninvasive glucose monitoring without painful blood collection. However, sweat-based glucose sensing still faces many challenges, such as difficulty in sweat collection, activity variation of glucose oxidase due to lactic acid secretion and ambient temperature changes, and delamination of the enzyme when exposed to mechanical friction and skin deformation. Precise point-of-care therapy in response to the measured glucose levels is still very challenging. We present a wearable/disposable sweat-based glucose monitoring device integrated with a feedback transdermal drug delivery module. Careful multilayer patch design and miniaturization of sensors increase the efficiency of the sweat collection and sensing process. Multimodal glucose sensing, as well as its real-time correction based on pH, temperature, and humidity measurements, maximizes the accuracy of the sensing. The minimal layout design of the same sensors also enables a strip-type disposable device. Drugs for the feedback transdermal therapy are loaded on two different temperature-responsive phase change nanoparticles. These nanoparticles are embedded in hyaluronic acid hydrogel microneedles, which are additionally coated with phase change materials. This enables multistage, spatially patterned, and precisely controlled drug release in response to the patient's glucose level. The system provides a novel closed-loop solution for the noninvasive sweat-based management of diabetes mellitus.

Antiangiogenic Effect of Bevacizumab: Application of Arterial Spin-Labeling Perfusion MR Imaging in a Rat Glioblastoma Model

BACKGROUND AND PURPOSE

The usefulness of arterial spin-labeling for the evaluation of the effect of the antiangiogenic therapy has not been elucidated. Our aim was to evaluate the antiangiogenic effect of bevacizumab in a rat glioblastoma model based on arterial spin-labeling perfusion MR imaging.

MATERIALS AND METHODS

DSC and arterial spin-labeling perfusion MR imaging were performed by using a 9.4T MR imaging scanner in nude rats with glioblastoma. Rats were randomly assigned to the following 3 groups: control, 3-day treatment, and 10-day treatment after bevacizumab injection. One-way analysis of variance with a post hoc test was used to compare perfusion parameters (eg, normalized CBV and normalized CBF from DSC MR imaging and normalized CBF based on arterial spin-labeling) with microvessel area on histology. The Pearson correlations between perfusion parameters and microvessel area were also determined.

RESULTS

All of the normalized CBV from DSC, normalized CBF from DSC, normalized CBF from arterial spin-labeling, and microvessel area values showed significant decrease after treatment (P < .001, P < .001, P = .005, and P < .001, respectively). In addition, normalized CBV and normalized CBF from DSC and normalized CBF from arterial spin-labeling strongly correlated with microvessel area (correlation coefficient, r = 0.911, 0.869, and 0.860, respectively; P < .001 for all).

CONCLUSIONS

Normalized CBF based on arterial spin-labeling and normalized CBV and normalized CBF based on DSC have the potential for evaluating the effect of antiangiogenic therapy on glioblastomas treated with bevacizumab, with a strong correlation with microvessel area.

Mechanism for enhanced 5-aminolevulinic acid fluorescence in isocitrate dehydrogenase 1 mutant malignant gliomas

Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) has become the main treatment modality in malignant gliomas. However unlike glioblastomas, there are inconsistent result about fluorescence status in WHO grade III gliomas. Here, we show that mutational status of IDH1 is linked to 5-ALA fluorescence. Using genetically engineered malignant glioma cells harboring wild type (U87MG-IDH1^WT) or mutant (U87MG-IDH1^R132H) IDH1, we demonstrated a lag in 5-ALA metabolism and accumulation of protoporphyrin IX (PpIX) in U87MG-IDH1^R132H cells. Next, we used liquid chromatography–mass spectrometry (LC-MS) to screen for tricarboxylic acid (TCA) cycle-related metabolite changes caused by 5-ALA exposure. We observed low baseline levels of NADPH, an essential cofactor for the rate-limiting step of heme degradation, in U87MG-IDH1^R132H cells. High levels of NADPH are required to metabolize excessive 5-ALA, giving a plausible reason for the temporarily enhanced 5-ALA fluorescence in mutant IDH1 cells. This hypothesis was supported by the results of metabolic screening in human malignant glioma samples. In conclusion, we have discovered a relationship between enhanced 5-ALA fluorescence and IDH1 mutations in WHO grade III gliomas. Low levels of NADPH in tumors with mutated IDH1 is responsible for the enhanced fluorescence.

A graphene-based electrochemical device with thermoresponsive microneedles for diabetes monitoring and therapy

Owing to its high carrier mobility, conductivity, flexibility and optical transparency, graphene is a versatile material in micro- and macroelectronics. However, the low density of electrochemically active defects in graphene synthesized by chemical vapour deposition limits its application in biosensing. Here, we show that graphene doped with gold and combined with a gold mesh has improved electrochemical activity over bare graphene, sufficient to form a wearable patch for sweat-based diabetes monitoring and feedback therapy. The stretchable device features a serpentine bilayer of gold mesh and gold-doped graphene that forms an efficient electrochemical interface for the stable transfer of electrical signals. The patch consists of a heater, temperature, humidity, glucose and pH sensors and polymeric microneedles that can be thermally activated to deliver drugs transcutaneously. We show that the patch can be thermally actuated to deliver Metformin and reduce blood glucose levels in diabetic mice.

On the Utility of Short Echo Time (TE) Single Voxel 1H-MRS in Non-Invasive Detection of 2-Hydroxyglutarate (2HG); Challenges and Potential Improvement Illustrated with Animal Models Using MRUI and LCModel

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) are frequently found in brain tumors, and the resulting onco–metabolite, 2–hydroxyglutarate (2HG), has been suggested to be a potential diagnostic and prognostic biomarker of the diseases. Indeed, recent studies have demonstrated the feasibility of non–invasively detecting 2HG by using proton magnetic resonance spectroscopy (1H–MRS). Due to severe spectral overlaps of 2HG with its background metabolites and spectral baselines, however, the majority of those previous studies employed spectral editing methods with long echo times (TEs) instead of the most commonly used short TE approach with spectral fitting. Consequently, the results obtained with spectral editing methods may potentially be prone to errors resulting from substantial signal loss due to relaxation. Given that the spectral region where the main signal of 2HG resides is particularly sensitive to spectral baseline in metabolite quantification, we have investigated the impact of incorporating voxel–specifically measured baselines into the spectral basis set on the performance of the conventional short TE approach in 2HG detection in rodent models (Fisher 344 rats; n = 19) of IDH1/2 mutant–overexpressing F98 glioma at 9.4T. Metabolite spectra were acquired (SPECIAL sequence) for a tumor region and the contralateral normal region of the brain for each animal. For the estimation of spectral baselines metabolite–nulled spectra were obtained (double–inversion–recovery SPECIAL sequence) for each individual voxels. Data were post–processed with and without the measured baselines using MRUI and LCModel—the two most widely used data post–processing packages. Our results demonstrate that in–vivo detection of 2HG using the conventional short TE approach is challenging even at 9.4T. However, incorporation of voxel–specifically measured spectral baselines may potentially improve its performance. Upon more thorough validation in a larger number of animals and more importantly in human patients, the potential utility of the proposed short TE acquisition with voxel–specific baseline measurement approach in 2HG detection may need to be considered in the study design.

Abstract B05: Mechanism for enhanced 5-aminolevulinic acid fluorescence in isocitrate dehydrogenase 1 mutant malignant gliomas

Fluorescence-guided surgery using 5-aminolevulinic acid (5-ALA) and the discovery of IDH1 mutations are major recent advances in glioma management and research. However, the mechanism underlying the selective intracellular accumulation of the 5-ALA derivative protoporphyrinogen IX (PpIX) and the metabolic effect of IDH1 mutations in malignant glioma cells are still not fully understood. Based on clinical experience, we hypothesized an association between enhanced 5-ALA fluorescence and IDH1 mutations in WHO grade III gliomas. Using genetically engineered malignant glioma cells harboring wild type (U87MG-IDH1WT) or mutant (U87MG-IDH1R132H) versions of IDH1, we confirmed a lag in 5-ALA metabolism and a temporary accumulation of PpIX in U87MG-IDH1R132H cells. To investigate the metabolic aspects of the mechanism responsible, we used liquid chromatography–mass spectrometry (LC-MS) to screen for tricarboxylic acid (TCA) cycle-related metabolite changes resulting from 5-ALA exposure. We observed low baseline levels of NADPH, an essential cofactor for the rate-limiting step of heme degradation, in U87MG-IDH1R132H cells. Abundant levels of NADPH are required to metabolize excessive 5-ALA, giving a plausible reason for the temporary enhanced 5-ALA fluorescence in mutant IDH1 cells. This hypothesis was supported by the results of metabolic screening in human malignant glioma samples. We discovered a relationship between enhanced 5-ALA fluorescence and IDH1 mutations in malignant gliomas and investigated the metabolic aspects of the mechanism responsible, identifying significantly different levels of NADPH between wild type and mutant IDH1 malignant glioma cells.

Citation Format: Kim Ja Eun, Hye Rim Cho, Wen Jun Xu, Young-Hoon Kim, Ji Hoon Phi, Seung Hong Choi, Sunghyouk Park, Chul-Kee Park. Mechanism for enhanced 5-aminolevulinic acid fluorescence in isocitrate dehydrogenase 1 mutant malignant gliomas. [abstract]. In: Proceedings of the AACR Special Conference: Advances in Brain Cancer Research; May 27-30, 2015; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2015;75(23 Suppl):Abstract nr B05.

Bioresorbable Electronic Stent Integrated with Therapeutic Nanoparticles for Endovascular Diseases

Implantable endovascular devices such as bare metal, drug eluting, and bioresorbable stents have transformed interventional care by providing continuous structural and mechanical support to many peripheral, neural, and coronary arteries affected by blockage. Although effective in achieving immediate restoration of blood flow, the long-term re-endothelialization and inflammation induced by mechanical stents are difficult to diagnose or treat. Here we present nanomaterial designs and integration strategies for the bioresorbable electronic stent with drug-infused functionalized nanoparticles to enable flow sensing, temperature monitoring, data storage, wireless power/data transmission, inflammation suppression, localized drug delivery, and hyperthermia therapy. In vivo and ex vivo animal experiments as well as in vitro cell studies demonstrate the previously unrecognized potential for bioresorbable electronic implants coupled with bioinert therapeutic nanoparticles in the endovascular system.

Magnetic resonance imaging of the pancreas in streptozotocin-induced diabetic rats: Gadofluorine P and Gd-DOTA

AIM: To investigate the performance of Gadofluorine P-enhanced magnetic resonance imaging (MRI) on the diagnosis of diabetes in a streptozotocin (STZ) -induced diabetic rat model.

METHODS: Fischer 344 rats were treated with STZ. Rats not treated with STZ served as controls. T1-weighted MRI was performed using a 3T scanner before and after the injection of Gd-DOTA or Gadofluorine P (6 diabetic rats, 5 controls). The normalized signal intensity (SI) and the enhancement ratio (ER) of the pancreas were measured at each time point, and the values were compared between the normal and diabetic rats using the Mann-Whitney test. In addition, the values were correlated with the mean islet number. Optimal cut-off values were calculated using a positive test based on receiver operating characteristics. Intrapancreatic Gd concentration after the injection of each contrast media was measured using laser ablation-inductively coupled plasma-mass spectrometry in a separate set of rats (4 diabetic rats, 4 controls for Gadofluorine P; 2, 2 for Gd-DOTA).

RESULTS: The normalized SI and ER of the pancreas using Gd-DOTA were not significantly different between diabetic rats and controls. With Gadofluorine P, the values were significantly higher in the diabetic rats than in the control rats 30 min after injection (P < 0.05). The area under the receiver operating characteristic curve that differentiated diabetic rats from the control group was greater for Gadofluorine P than for Gd-DOTA (0.967 vs 0.667, P = 0.085). An increase in normalized SI 30 min after Gadofluorine P was correlated with a decrease in the mean number of islets (r² = 0.510, P = 0.014). Intra-pancreatic Gd was higher in rats with Gadofluorine P injection than Gd-DOTA injection (Gadofluorine P vs Gd-DOTA, 7.37 vs 0.00, P < 0.01). A significant difference in the concentration of intrapancreatic Gd was observed between the control and diabetic animals that were sacrificed 30 min after Gadofluorine P injection (control vs diabetic, 3.25 ng/g vs 10.55 ng/g, P < 0.05)

CONCLUSION: In this STZ-induced diabetes rat model, Gadofluorine P-enhanced MRI of the pancreas showed high accuracy in the diagnosis of diabetes.

Multifunctional cell-culture platform for aligned cell sheet monitoring, transfer printing, and therapy

While several functional platforms for cell culturing have been proposed for cell sheet engineering, a soft integrated system enabling in vitro physiological monitoring of aligned cells prior to their in vivo applications in tissue regeneration has not been reported. Here, we present a multifunctional, soft cell-culture platform equipped with ultrathin stretchable nanomembrane sensors and graphene-nanoribbon cell aligners, whose system modulus is matched with target tissues. This multifunctional platform is capable of aligning plated cells and in situ monitoring of cellular physiological characteristics during proliferation and differentiation. In addition, it is successfully applied as an in vitro muscle-on-a-chip testing platform. Finally, a simple but high-yield transfer printing mechanism is proposed to deliver cell sheets for scaffold-free, localized cell therapy in vivo. The muscle-mimicking stiffness of the platform allows the high-yield transfer printing of multiple cell sheets and results in successful therapies in diseased animal models. Expansion of current results to stem cells will provide unique opportunities for emerging classes of tissue engineering and cell therapy technologies.

Polymeric embolization coil of bilayered polyvinyl alcohol strand for therapeutic vascular occlusion: a feasibility study in canine experimental vascular models

PURPOSE

To investigate the feasibility of polyvinyl alcohol (PVA) polymer coil as a new endovascular embolic agent and to gauge the related histologic response in a canine vascular model.

MATERIALS AND METHODS

PVA polymer coil was fabricated by cross-linking PVA and tantalum particles. Basic properties were then studied in vitro via swelling ratio and bending diameter. Normal renal segmental arteries and wide-necked aneurysms of carotid sidewalls served as canine vascular models. Endovascular PVA coil embolization of normal renal segmental arteries (N = 20) and carotid aneurysms (N = 8) was performed under fluoroscopic guidance in 10 dogs. Degree of occlusion was assessed immediately and at 4 weeks after embolization by conventional and computed tomographic angiography. Histologic features were also graded at acute (day 1, six segmental arteries and four aneurysms) and chronic phases (week 4, 14 segmental arteries and four aneurysms) after embolization to assess inflammation, organization of thrombus, and neointimal proliferation.

RESULTS

Swelling ratio declined as concentrations of cross-linking agent increased. Mean bending diameters were 2.05 mm (range, 0.86-6.25 mm) in water at 37 °C and 2.29 mm (range, 0.94-6.38 mm) in canine blood samples at 37 °C. Occlusion of normal renal segmental arteries was sustained (complete occlusion at day 1, n = 20; at week 4, n = 14), whereas immediate outcomes in carotid aneurysms (day 1, complete occlusion, n = 5; residual neck only, n = 3) were not sustained (week 4, complete occlusion, n = 1; minor recanalization, n = 1; major recanalization, n = 2). At week 4, chronic inflammatory cells predominated, with progressive organization of thrombus and fibrocellular ingrowth. All aneurysms bore full neointimal linings on the coil mass in the chronic phase.

CONCLUSIONS

Vascular occlusion by PVA polymer coil proved superior in normal renal segmental arteries and feasible in surgically constructed carotid aneurysms (with packing densities ≥ 30%), constituting acceptable radiologic feasibility and histologic response.

Optimization of ultrasmall superparamagnetic iron oxide (P904)-enhanced magnetic resonance imaging of lymph nodes: initial experience in a mouse model

BACKGROUND

P904 is a novel ultra-small superparamagnetic iron oxide (USPIO) contrast agent. This study was conducted to investigate the optimal dose of P904 for magnetic resonance imaging (MRI) of lymph nodes.

MATERIALS AND METHODS

T2*-weighted 3T MRI was performed in 14 normal mice before and 24 h after P904 injection at varying doses. Normalized signal intensity (nSI), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast ratio (CR) were calculated to determine the optimal dose. MRI of the metastatic lymph node models (n=5) was acquired using the optimal dose and correlated with pathological results to calculate sensitivity and specificity. The mean SI ratio between pre- and postcontrast MRI was also calculated for each lymph node.

RESULTS

The mean nSI and SNR values on postcontrast images were significantly lower at 300 μmol Fe/kg than at 75 μmol Fe/kg (p<0.001). The mean CNR and CR values were significantly higher at 300 μmol Fe/kg than at the other two doses (p<0.05). At the optimal dose of 300 μmol Fe/kg, the mean SI ratio of benign lymph nodes was significantly lower than that of metastatic lymph nodes (p<0.001). The Az (areas under the receiver operating characteristic curves) value for diagnosing lymph node metastasis at the optimal dose was 0.97.

CONCLUSION

The optimal dose for P904-enhanced MRI of the lymph nodes was 300 μmol Fe/kg, which could be used for the diagnosis of lymph node metastasis.

An NMR metabolomics approach for the diagnosis of leptomeningeal carcinomatosis in lung adenocarcinoma cancer patients

Leptomeningeal carcinomatosis (LC) is a metastatic cancer invading the central nervous system (CNS). We previously reported a metabolomic diagnostic approach as tested on an animal model and compared with current modalities. Here, we provide a proof of concept by applying it to human LC originating from lung cancer, the most common cause of CNS metastasis. Cerebrospinal fluid from LC (n = 26) and normal groups (n = 41) were obtained, and the diagnosis was established with clinical signs, cytology, MRI and biochemical tests. The cytology on the CSF, the current gold standard, exhibited 69% sensitivity (~100% specificity) from the first round of CSF tapping. In comparison, the nuclear magnetic resonance spectra on the CSF showed a clear difference in the metabolic profile between the LC and normal groups. Multivariate analysis and cross-validation yielded the diagnostic sensitivity of 92%, the specificity of 96% and the area under the curve (AUC) of 0.991. Further spectral and statistical analysis identified myo-inositol (p < 5 × 10(-14)), creatine (p < 7 × 10(-8)), lactate (p < 9 × 10(-4)), alanine (p < 7.9 × 10(-3)) and citrate (p < 3 × 10(-4)) as the most contributory metabolites, whose combination exhibited an receiver-operating characteristic diagnostic AUC of 0.996. In addition, the metabolic profile could be correlated with the grading of radiological leptomeningeal enhancement (R(2) = 0.3881 and p = 6.66 × 10(-4)), suggesting its potential utility in grading LC. Overall, we propose that the metabolomic approach might augment current diagnostic modalities for LC, the accurate diagnosis of which remains a challenge.

Reproducibility of histogram and texture parameters derived from intravoxel incoherent motion diffusion-weighted MRI of FN13762 rat breast Carcinomas

AIM

To determine the reproducibility of histogram and texture parameters derived from intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (MRI) of FN13762 rat breast carcinomas.

MATERIALS AND METHODS

IVIM diffusion-weighted MRI was performed twice, nine days after tumor implantation in 11 rats. At each session, histogram and texture parameters of entire tumors were extracted from apparent diffusion coefficient (ADC), true-diffusion coefficient (Dt), pseudo-diffusion coefficient (Dp), and perfusion fraction (Pf) maps. Intraobserver and interscan measurement reproducibilities were evaluated using intraclass correlation coefficients (ICC).

RESULTS

Mean, entropy, 5th, 10th, 25th percentiles from ADC and Dt maps revealed good intra-observer and interscan agreements [lower limits of 95% confidence interval (CI) for ICC≥0.75]. However, all parameters from Dp and Pf maps gave relatively poor intra-observer and interscan agreements (lower limits of 95% CI for ICC<0.75).

CONCLUSION

Histogram and texture parameters derived from ADC and Dt maps were more reproducible than those from Dp and Pf maps.

Rat model of hindlimb ischemia induced via embolization with polyvinyl alcohol and N-butyl cyanoacrylate

Objective

To investigate the feasibility of a rat model on hindlimb ischemia induced by embolization from the administration of polyvinyl alcohol (PVA) particles or N-butyl cyanoacrylate (NBCA).

Materials and Methods

Unilateral hindlimb ischemia was induced by embolization with NBCA (n = 4), PVA (n = 4) or surgical excision (n = 4) in a total of 12 Sprague-Dawley rats. On days 0, 7 and 14, the time-of-flight magnetic resonance angiography (TOF-MRA) and enhanced MRI were obtained as scheduled by using a 3T-MR scanner. The clinical ischemic index, volume change and degree of muscle necrosis observed on the enhanced MRI in the ischemic hindlimb were being compared among three groups using the analysis of variance. Vascular patency on TOF-MRA was evaluated and correlated with angiographic findings when using an inter-rater agreement test.

Results

There was a technical success rate of 100% for both the embolization and surgery groups. The clinical ischemic index did not significantly differ. On day 7, the ratios of the muscular infarctions were 0.436, 0.173 and 0 at thigh levels and 0.503, 0.337 and 0 at calf levels for the NBCA, PVA and surgery groups, respectively. In addition, the embolization group presented increased volume and then decreased volume on days 7 and 14, respectively. The surgery group presented a gradual volume decrease. Good correlation was shown between the TOF-MRA and angiographic findings (kappa value of 0.795).

Conclusion

The examined hindlimb ischemia model using embolization with NBCA and PVA particles in rats is a feasible model for further research, and muscle necrosis was evident as compared with the surgical model.

Blood oxygen level-dependent MRI for evaluation of early response of liver tumors to chemoembolization: an animal study

AIM

To evaluate the feasibility of carbogen-challenge blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) for assessing the early response of liver tumors to chemoembolization in a rat hepatoma model.

MATERIALS AND METHODS

In a 9.4-Tesla scanner, a multiple gradient-recalled echo sequence was utilized for R2* measurement at 11 and 13 days after tumor implantation, first during room air breathing and then with carbogen gas (95% O2/5% CO2) breathing, to calculate the percentage changes of R2* values [ΔR2*(%)]. Transarterial chemoembolization was conducted 12 days after tumor implantation.

RESULTS

The ΔR2* value of the tumors was 10.61 ± 8.94% on pre-chemoembolization images and -0.16 ± 1.85% on post-chemoembolization images. There was a significant difference in the ΔR2* value of the tumors between pre-chemoembolization and post-chemoembolization BOLD MRI (p=0.013).

CONCLUSION

Carbogen-challenge BOLD MRI can be a non-invasive and useful method for the evaluation of early response of liver tumors to chemoembolization.

Sprague-Dawley rats bearing McA-RH7777 cells for study of hepatoma and transarterial chemoembolization

AIM

To evaluate the feasibility of the McA-RH7777 tumor model in Sprague-Dawley (SD) rats, for study of hepatoma and transarterial chemoembolization.

MATERIALS AND METHODS

McA-RH7777 rat hepatoma cells (1×10(7)) were inoculated into the left hepatic lobe of SD rats (n=38). Chemoembolization with left common carotid artery access was performed using an emulsion of iodized oil and doxorubicin, and polyvinyl alcohol particles. Tumor induction rate and response to chemoembolization were assessed by magnetic resonance imaging and histology.

RESULTS

Tumor induction rate of McA-RH7777 in SD rat livers was 73.3% (11/15). Hematoxylin-and-eosin staining revealed hypercellular tumor with a trabecular pattern that mimics human hepatocellular carcinoma. Chemoembolization was successfully conducted in all rats. There was a significant difference in tumor growth rates between the chemoembolization-treated and control groups (p<0.0001).

CONCLUSION

A rat tumor model of McA-RH7777 cells in SD rats is feasible and has the potential to be a good model for hepatoma and chemoembolization studies.

An NMR metabolomics approach for the diagnosis of leptomeningeal carcinomatosis

Leptomeningeal carcinomatosis (LC) is the third most common metastatic complication of the central nervous system. However, the current modalities to reliably diagnose this condition are not satisfactory. Here, we report a preclinical proof of concept for a metabolomics-based diagnostic strategy using a rat LC model incorporating glioma cells that stably express green fluorescent protein. Cytologic diagnoses gave 66.7% sensitivity for the 7-day LC group and 0% for the 3-day LC group. MR imaging could not diagnose LC at these stages. In contrast, nuclear magnetic resonance-based metabolomics on cerebrospinal fluid detected marked differences between the normal and LC groups. Predictions based on the multivariate model provided sensitivity, specificity, and overall accuracy of 88% to 89% in both groups for LC diagnosis. Further statistical analyses identified lactate, acetate, and creatine as specific for the 7-day LC group, with glucose a specific marker of the normal group. Overall, we showed that the metabolomics approach provided both earlier and more accurate diagnostic results than cytology and MR imaging in current use.

Effects of Polycan, a β-glucan, on experimental periodontitis and alveolar bone loss in Sprague-Dawley rats

BACKGROUND AND OBJECTIVE

Polycan is a promising candidate for the treatment of periodontal disease. This study was undertaken to examine whether Polycan, a type of β-glucan, has a protective effect on ligature-induced experimental periodontitis and related alveolar bone loss in Sprague-Dawley rats.

MATERIAL AND METHODS

 Polycan was orally administered, daily, for 10 d, at 21.25, 42.5 or 85 mg/kg, beginning 1 d after ligation. Changes in body weight and alveolar bone loss were monitored, and the anti-inflammatory effects of Polycan were determined by measuring the levels of myeloperoxidase (MPO), interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in gingival tissue. We also evaluated inducible nitric oxide synthase (iNOS) activity and malondialdehyde (MDA) concentrations as a measure of the antioxidant effect.

RESULTS

Ligature placement led to a marked decrease in body weight, increased alveolar bone loss and increased concentrations of MPO, IL-1β, TNF-α and MDA, as well as increased iNOS activity and inflammatory cell infiltration and decreased collagen-fiber content. Histological examination revealed increases in the number and activity of osteoclast cells, decreases in alveolar bone volume and elevated percentages of osteclasts on the alveolar bone surface. Daily oral treatment with 42.5 or 85 mg/kg of Polycan for 10 d led to significant, dose-dependent inhibition of the effect of ligature placement.

CONCLUSION

Taken together, these results suggest that 10 d of oral treatment with Polycan effectively inhibits ligature placement-induced periodontitis and related alveolar bone loss via an antioxidant effect.

Imaging and quantification of metastatic melanoma cells in lymph nodes with a ferritin MR reporter in living mice

Cellular MRI with a reporter gene offers the opportunity to track small numbers of tumor cells and to study metastatic processes in their earliest developmental stages in the target organs of interest. This study demonstrates the feasibility of using the MR reporter ferritin for the noninvasive imaging and quantification of metastatic melanoma cells in the lymph nodes (LNs) of living mice. A B16F10 murine melanoma cell line expressing human ferritin heavy chain (hFTH) and green fluorescent protein (GFP) was constructed to allow the detection of cells by MRI and fluorescence imaging. Stable overexpression of hFTH and GFP in B16F10 murine melanoma cells was feasible and showed no cellular toxicity. In addition, hFTH cells were detectable by 9.4-T MRI in  vitro and in  vivo, yielding significant changes in T(2)* relative to control cells. In BALB/c nude mice, the presence of hFTH- and GFP-expressing metastatic melanoma cells in deep-seated axillary LNs was demonstrated as areas of low T(2)* on MRI, but the same LNs were not visible by fluorescence imaging because the light was unable to penetrate the tissue. Furthermore, the metastatic volume of each LN, which was assessed by cumulative histogram analysis of the T(2)* MRI data, correlated well with tumor burden, which was determined by histology (r = -0.8773, p = 0.0001). This study is the first to use MRI and an MR reporter gene for both the visualization and quantification of metastatic cancer cells in LNs.

Macrophages homing to metastatic lymph nodes can be monitored with ultrasensitive ferromagnetic iron-oxide nanocubes and a 1.5T clinical MR scanner

Background

Due to the ability of macrophages to specifically home to tumors, their potential use as a delivery vehicle for cancer therapeutics has been suggested. Tracking the delivery and engraftment of macrophages into human tumors with a 1.5T clinical MR scanner requires the development of sensitive contrast agents for cell labeling. Therefore, this study aimed to determine whether intravenously injected macrophages could target a primary tumor as well as metastatic LNs, and whether these cells could be detected in vivo by MRI.

Methodology

Peritoneal macrophages were obtained from BALB/c nude mice. The viability, phagocytotic capacity and migratory activity of the macrophages were assessed. MR imaging was performed using a clinical 1.5 T MR scanner and we estimated the T2* of the labeled macrophages. Metastatic lymph nodes were produced in BALB/c nude mice. We administrated 2×10⁶ macrophages labeled with 50 µg Fe/mL FIONs intravenously into the mice. In the 3D T2* GRE MR images obtained one day after the injection of the labeled macrophages or FION solution, the percentages of pixels in the tumors or LNs below the minimum normalized SI (signal intensity) threshold were summated and reported as the black pixel count (%) for the FION hypointensity. Tumors in the main tumor model as well as the brachial, axillary and inguinal lymph nodes in the metastatic LN models were removed and stained. For all statistical analyses, single-group data were assessed using t test or the Mann-Whitney test. Repeated measurements analysis of variance (ANOVA) with Tukey–Kramer post hoc comparisons were performed for multiple comparisons.

Conclusions

The FION-labeled macrophages, which could be non-invasively monitored using a 1.5 T clinical MR scanner, targeted both the main tumors and LN metastases. Overall, the results of this study suggest that the use of macrophages may have many future applications in the clinic for vectorizing therapeutic agents toward main tumors as well as LN metastases.

In vivo imaging of tumor transduced with bimodal lentiviral vector encoding human ferritin and green fluorescent protein on a 1.5T clinical magnetic resonance scanner

A combination of reporter genes for magnetic resonance imaging (MRI) and optical imaging can provide an additional level of noninvasive and quantitative information about biological processes occurring in deep tissues. We developed a bimodal lentiviral vector to monitor deep tissue events using MRI to detect myc-tagged human ferritin heavy chain (myc-hFTH) expression and fluorescence imaging to detect green fluorescent protein (GFP) expression. The transgene construct was stably transfected into MCF-7 and F-98 cells. After transplantation of the cells expressing myc-hFTH and GFP into mice or rats, serial MRI and fluorescence imaging were performed with a human wrist coil on a 1.5T MR scanner and optical imaging analyzer for 4 weeks. No cellular toxicity due to overexpression of myc-hFTH and GFP was observed in MTT and trypan blue exclusion assays. Iron accumulation was observed in myc-hFTH cells and tumors by Prussian blue staining and iron binding assays. The myc-hFTH cells and tumors had significantly lower signal intensities in T(2)-weighted MRI than mock-transfected controls (P ≤ 0.05). This is direct evidence that myc-hFTH expression can be visualized noninvasively with a 1.5T clinical MR scanner. This study shows that MRI and fluorescence imaging of transplanted cells at molecular and cellular levels can be performed simultaneously using our bimodal lentiviral vector system. Our techniques can be used to monitor tumor growth, metastasis, and regression during cell and gene-based therapy in deep tissues.

Isolated acute cellular rejection of the liver after simultaneous liver and kidney transplantation: a case report

Simultaneous liver and kidney transplantation (SLKT) is now considered the treatment of choice for patients with concurrent end-stage liver and kidney diseases. Even though the early postoperative mortality rate following SLKT is reported to be high compared to that of liver transplantation alone, the liver graft from the same donor has been argued to induce better kidney graft acceptance as evidenced by a low rate of acute renal rejection episodes. There have been many reports of a low incidence of acute renal rejection following SLKT; however, only a few cases were proven by simultaneous biopsies. The authors experienced a case of biopsy-proven isolated acute cellular rejection of the liver graft following SLKT.

Induction of MMP-13 expression by soluble human glucocorticoid-induced tumor necrosis factor receptor in fibroblast-like synovial cells

OBJECTIVE

We tested the hypothesis that human glucocorticoid-induced tumor necrosis factor receptor (hGITR/TR11) expressed on the surface of activated CD4(+) T cells is responsible for up-regulating the production of matrix metalloproteinase (MMP)-13 by fibroblast-like synoviocytes (FLSs).

METHODS

The level of MMP-13 was measured by Western blot and reverse transcriptase polymerase chain reaction (RT-PCR). Expressions of hGITR ligand (hGITRL) on the surface of FLSs and hGITR on the surface of human CD4(+) T cells were analyzed by flow cytometry and RT-PCR. Neutralizing antibodies (Abs) were used to block hGITRL and hGITR on the surface of FLSs and human CD4(+) T cells, respectively. Human CD4(+) T cells were cocultured with FLSs to facilitate interaction between hGITR on CD4(+) T cells and hGITRL on FLSs.

RESULTS

Soluble hGITR (shGITR) stimulated FLSs to produce MMP-13, and blockade of hGITRL reduced this effect. Direct contact between activated CD4(+) T and FLSs also induced the production of MMP-13, and neutralization of hGITR on activated CD4(+) T cells during coculture decreased the amount of MMP-13 produced by FLSs.

CONCLUSION

shGITR stimulated FLSs to produce MMP-13 via a signal through hGITRL. Direct contact between activated CD4(+) T cells and FLSs facilitated hGITR-hGITRL interaction, and resulted in inducing MMP-13. This effect may increase tissue destruction in chronic inflammation such as rheumatoid arthritis (RA).

Blockade of 4-1BB (CD137)/4-1BB ligand interactions increases allograft survival

We investigated the role of 4-1BB, a T cell co-stimulatory molecule, in alloimmune responses. In vivo mixed lymphocyte reactions showed that 4-1BB was preferentially expressed on actively dividing CD4(+) and CD8(+) T cells. Furthermore, following alloantigen challenge, the draining lymph nodes contained subpopulations of 4-1BB-expressing CD4(+) and CD8(+) T cells. 4-1BB-deficient C57BL/6 mice showed a delayed rejection of cardiac transplants mismatched for the major histocompatibility complex. Longer transplant survival was induced by blockade of 4-1BB/4-1BB ligand (4-1BBL) interactions using an anti-4-1BBL monoclonal antibody. Histological analysis showed that prolonged transplant survival in the 4-1BB-deficient and anti-4-1BBL-treated mice correlated with reduced lymphocytic infiltration and vasculitis in the donor heart tissue. Taken together, our data suggest that blockade of 4-1BB/4-1BBL interactions inhibited the expansion of alloreactive T cells and reduced CTL activity against host alloantigen, which in turn resulted in the prolongation of allograft survival. Blockade of the 4-1BB co-stimulatory pathway may be useful for preventing allograft rejection.

Analysis of expression and function of the costimulatory molecule 4-1BB in alloimmune responses

BACKGROUND

4-1BB (CD137) is a T cell costimulatory molecule that promotes T cell activation. In this study, we investigated the role of 4-1BB costimulation in allogeneic T cell responses.

METHODS

Vascularized heart transplantation, allogeneic mixed leukocyte reaction (MLR), and graft versus host disease models were used to examine 4-1BB and 4-1BBL expression. In addition, agonistic anti-4-1BB antibodies were used in MLR to functionally analyze T cell responses.

RESULTS

Using a heart transplant model, we found that 4-1BB and 4-1BBL transcripts were both expressed in rejecting cardiac grafts. In the allogeneic MLR, 4-1BB was expressed on both activated CD4 and CD8 T cells and 4-1BB was expressed on T cells after multiple cell divisions in vivo. Functionally, 4-1BB was a potent stimulator of proliferation, cytokine secretion, and CD25 expression by CD8 T cells, but 4-1BB signals had a weak effect on the proliferation of CD4 T cells. Because 4-1BB promoted the secretion of IL-2 and the expression of CD25 on CD8 T cells, we investigated whether IL-2 was the only factor whereby 4-1BB signals induced CD8 T cell proliferation. Although IL-2 was required for optimal CD8 T cell proliferation, 4-1BB also costimulated CD8 T cell proliferation independently of IL-2.

CONCLUSIONS

This study demonstrates that 4-1BB is expressed on activated, maximally divided T cells and shows that 4-1BB promotes CD8 T cell proliferation by enhancing signals through the IL-2 receptor and by other mechanisms independent of the IL-2 pathway.

Transplantation of the bone marrow microenvironment leads to hematopoietic chimerism without cytoreductive conditioning

BACKGROUND

It has been hypothesized that regimens to induce transplantation tolerance and long-term hematopoietic chimerism require recipient conditioning with whole body irradiation or a cytoablative regimen to create space within the marrow microenvironment to permit pluripotent stem cell engraftment. The purpose of this study was to determine if transplantation of an intact bone marrow microenvironment in the form of a bone graft would permit stable hematopoietic stem cell engraftment, shape the repertoire of developing T cells, and induce donor-specific unresponsiveness in the absence of a conditioning regimen.

METHODS

Fragments of femur were transplanted under the kidney capsule of recipient mice. At defined time points after bone graft transplantation recipients were assayed for chimerism, bone graft viability, and responses to donor and third party alloantigens in vitro and in vivo.

RESULTS

In the absence of an immunological barrier, bone graft transplantation resulted in long-term multi-lineage hematopoietic chimerism in the peripheral blood. Nude bone graft transplantation into SCID recipients resulted in development of donor- derived T cells that underwent negative selection on bone graft derived I-E+ cells within the thymus. Across a fully allogeneic barrier in immunocompetent recipients treated with combined blockade of the CD40 and CD28 pathways bone graft transplantation resulted in long-term donor-specific hyporesponsiveness in vitro and acceptance of donor specific skin grafts.

CONCLUSIONS

Transplantation of bone marrow in the form of a bone graft may facilitate the production of hematopoietic chimerism and lead to long-term donor-specific hyporesponsiveness in the absence of a cytoreductive conditioning regimen.

Vigorous allograft rejection in the absence of danger

Tolerance to self is a necessary attribute of the immune system. It is thought that most autoreactive T cells are deleted in the thymus during the process of negative selection. However, peripheral tolerance mechanisms also exist to prevent development of autoimmune diseases against peripheral self-Ags. It has been proposed that T cells develop tolerance to peripheral self-Ags encountered in the absence of inflammation or "danger" signals. We have used immunodeficient Rag 1-/- mice to study the response of T cells to neo-self peripheral Ags in the form of well-healed skin and vascularized cardiac allografts. In this paper we report that skin and cardiac allografts without evidence of inflammation are vigorously rejected by transferred T cells or when recipients are reconstituted with T cells at a physiologic rate by nude bone graft transplantation. These results provide new insights into the role of inflammation or "danger" in the initiation of T cell-dependent immune responses. These findings also have profound implications in organ transplantation and suggest that in the absence of central deletional tolerance, peripheral tolerance mechanisms are not sufficient to inhibit alloimmune responses even in the absence of inflammation or danger.

Prolonged acceptance of concordant and discordant xenografts with combined CD40 and CD28 pathway blockade

BACKGROUND

The prompt and vigorous immune response to xenogenic tissue remains a significant barrier to clinical xenotransplantation. Simultaneous blockade of the CD28 and CD40 costimulatory pathways has been shown to dramatically inhibit the immune response to alloantigen.

METHODS

. In this study, we investigated the ability of simultaneous blockade of the CD28 and CD40 pathways to inhibit the immune response to xenoantigen in the rat-to-mouse and pig-to-mouse models.

RESULTS

Simultaneous blockade of the CD28 and CD40 pathways produced marked inhibition of the cellular response to xenoantigen in vivo and produced long-term acceptance of xenogeneic cardiac and skin grafts (rat-to-mouse), and markedly suppressed an evoked antibody response to xenoantigen. In addition, this strategy significantly prolonged the survival of pig skin on recipient mice.

CONCLUSIONS

Long-term hyporesponsiveness to xenoantigen across both a concordant and discordant species barrier, measured by the stringent criterion of skin grafting, can be achieved using a noncytoablative treatment regimen.

Reduced expression of tissue inhibitor of metalloproteinase in nodal metastasis of stomach cancer

The matrix metalloproteinases (MMPs) have been associated with tumor cell invasion and metastasis of human cancers by mediating the degradation of extracellular matrix components. Therefore, these enzymes and their inhibitor (TIMP-2) constitute promising targets in the development of anticancer therapies. In order to investigate the correlation between expressions of TIMP-2, MMPs and clinical outcome, immunohistochemical staining of MMP-2, MMP-9, and TIMP-2 were performed on paraffin-embedded tissue sections of 15 early gastric cancers (EGC) and 15 advanced gastric carcinomas (AGC) without nodal metastasis and 15 AGC with nodal metastasis (AGCn+). MMP-2 and MMP-9 were expressed in neoplastic cell plasma membrane in 83.3% and 88% of cases of AGC, respectively with inter-tumoral variability of staining intensity. MMP-2 and MMP-9 staining were not correlated with presence of nodal metastasis or degree of invasion depth at the time of diagnosis (p>0.05). The immunoreactivity of TIMP-2 was detected in the peri-tumoral stroma. Residual benign stomach tissue showed no or weak immunoreactivity for TIMP-2 staining. Among AGC, neoplasms with diffuse and strong TIMP-2 staining have less frequent metastasis (28.6%) than cases with focal and weak (68.8%) (p<0.05). Early gastric cancer revealed diffuse and strong TIMP-2 expressions. We conclude that clinical outcome such as depth of invasion or metastasis is more closely related to the expression of TIMP-2 than the corresponding MMPs.