scholarly journals In Vivo Brain Region-specific TSPO Imaging by PET/MRI [18F]FEPPA

2020 ◽  
Author(s):  
Chi-Wei Chang ◽  
Chuang-Hsin Chiu ◽  
Ming-Hsien Lin ◽  
Hung-Ming Wu ◽  
Tsung-Hsun Yu ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Western Blotting ◽  
Second Generation ◽  
Translocator Protein ◽  
Mrna Levels ◽  
Peripheral Tissues ◽  
Lps Challenge ◽  
Tnf Α ◽  
The Brain

Abstract Background: Expression of translocator protein (TSPO) on the outer mitochondrial membrane of activated microglia is strongly associated with neuroinflammation. The second-generation PET ligand [18F]FEPPA specifically binds TSPO to enable in vivo visualization and quantification of neuroinflammation. We optimized an fully automated radiosynthesis method and evaluated the utility of [18F]FEPPA, the second-generation PET ligand specifically binds TSPO, in a mouse model of systemic LPS challenge to detect TSPO-associated signals of central and peripheral inflammation. In vivo dynamic PET/MR imaging was performed in LPS-induced and control mice after [18F]FEPPA administration. The relationship between the [18F]FEPPA signal and the dose of LPS was assessed. The cytokine levels (i.e. TNF-α, Il-1β, Il-6) in LPS-induced mice were measured by RT-PCR. Standard uptake value (SUV), total volume of distribution (VT) and area under the curve (AUC) were determined based on the metabolite-uncorrected plasma input function. Western blotting and immunostaining were used to measure TSPO expression in the brain. Results: The fully automated [18F]FEPPA radiosynthesis produced an uncorrected radiochemical yield of 30 ± 2% within 80 min, with a radiochemical purity greater than 99% and specific activity of 148.9‒216.8 GBq/µmol. Significant differences were observed in the brain after [18F]FEPPA administration: SUV, VT, and AUC were 1.61 ± 0.1, 1.25 ± 0.12, and 1.58 ± 0.09-fold higher in LPS-injected mice than controls. TNF-α, Il-1β and Il-6 mRNA levels were also elevated in the brains of LPS-injected mice. Western blotting revealed TSPO (p<0.05) and Iba-1 (p<0.01) were upregulated in the brain after LPS administration. In LPS-injected mice, TSPO immunoactivity colocalized with Iba-1 in the cerebrum and TSPO was significantly overexpressed in the hippocampus and cerebellum. The peripheral organs (heart, lung) of LPS-injected mice had higher [18F]FEPPA signal-to-noise ratios than control mice. Conclusions: Based on the robust data on ligand specificity and selectivity in both central and peripheral tissues using 7T PET/MR imaging, we demonstrate that the high affinity, stability and high-contrast visualization indicate detection of TSPO using [18F]FEPPA represents a promising, specific biomarker for early diagnosis and neuropathological follow-up of neuroinflammatory processes.

scholarly journals GMP-compliant fully automated radiosynthesis of [18F]FEPPA for PET/MRI imaging of regional brain TSPO expression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chi-Wei Chang ◽  
Chuang-Hsin Chiu ◽  
Ming-Hsien Lin ◽  
Hung-Ming Wu ◽  
Tsung-Hsun Yu ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Western Blotting ◽  
Second Generation ◽  
Mrna Levels ◽  
Automated Radiosynthesis ◽  
Lps Challenge ◽  
Tnf Α ◽  
The Brain ◽  
Tspo Expression

Abstract Background Expression of translocator protein (TSPO) on the outer mitochondrial membrane of activated microglia is strongly associated with neuroinflammation. The second-generation PET ligand [18F]FEPPA specifically binds TSPO to enable in vivo visualization and quantification of neuroinflammation. We optimized a fully automated radiosynthesis method and evaluated the utility of [18F]FEPPA, the second-generation PET ligand specifically binds TSPO, in a mouse model of systemic LPS challenge to detect TSPO-associated signals of central and peripheral inflammation. In vivo dynamic PET/MR imaging was performed in LPS-induced and control mice after [18F]FEPPA administration. The relationship between the [18F]FEPPA signal and the dose of LPS was assessed. The cytokine levels (i.e., TNF-α, Il-1β, Il-6) in LPS-induced mice were measured by RT-PCR. Standard uptake value (SUV), total volume of distribution (VT) and area under the curve (AUC) were determined based on the metabolite-uncorrected plasma input function. Western blotting and immunostaining were used to measure TSPO expression in the brain. Results The fully automated [18F]FEPPA radiosynthesis produced an uncorrected radiochemical yield of 30 ± 2% within 80 min, with a radiochemical purity greater than 99% and specific activity of 148.9‒216.8 GBq/µmol. Significant differences were observed in the brain after [18F]FEPPA administration: SUV, VT and AUC were 1.61 ± 0.1, 1.25 ± 0.12 and 1.58 ± 0.09-fold higher in LPS-injected mice than controls. TNF-α, Il-1β and Il-6 mRNA levels were also elevated in the brains of LPS-injected mice. Western blotting revealed TSPO (p < 0.05) and Iba-1 (p < 0.01) were upregulated in the brain after LPS administration. In LPS-injected mice, TSPO immunoactivity colocalized with Iba-1 in the cerebrum and TSPO was significantly overexpressed in the hippocampus and cerebellum. The peripheral organs (heart, lung) of LPS-injected mice had higher [18F]FEPPA signal-to-noise ratios than control mice. Conclusions Based on the current data on ligand specificity and selectivity in central tissues using 7 T PET/MR imaging, we demonstrate that [18F]FEPPA accumulations significant increased in the specific brain regions of systemic LPS-induced neuroinflammation (5 mg/kg). Future investigations are needed to determine the sensitivity of [18F]FEPPA as a biomarker of neuroinflammation as well as the correlation between the PET signal intensity and the expression levels of TSPO.

Abstract 3653: Akt3 Offers Stronger Protection than Akt1 Against Brain Injury by Differentially Promoting Mtor Protein Levels In Both In Vitro and In Vivo Stroke Models

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Rong Xie ◽  
Michelle Cheng ◽  
Mei Li ◽  
Robert Sapolsky ◽  
Heng Zhao
Keyword(s):  
Gene Transfer ◽  
Western Blotting ◽  
Ischemic Injury ◽  
Akt Pathway ◽  
Over Expression ◽  
Protein Levels ◽  
Akt Isoforms ◽  
The Brain

Background and Objective: Akt is a serine-threonine kinase that plays critical role in promoting cell survival. Akt consists of three isoforms (Akt1, 2, 3), with Akt3 predominantly expressed in the brain. Although Akt pathway has been shown to mediate neuronal survival in cerebral ischemic injury, it is unclear how these Akt isoforms contribute to neuronal protection, and whether exogenous Akt can protect the brain against ischemic injury or not. In this study, we over-expressed Akt isoforms and its downstream signaling proteins such as FKHR and PRAS40 to investigate the role of the Akt pathway along with its potential relationship with the mTOR pathway in stroke. Methods: Sprauge Dawley rats (250∼280g) were used for all studies. A lentiviral vector consists of a CMV promoter driving IRES-eGFP was used to clone an active Akt 1 and 3 (cAKt 1 and 3), dominant-negative Akt (AktDN), active FKHR (AAA FKHR), and PRAS40. Lentivirus expressing these genes were added to primary mixed cortical cultures for two days prior to oxygen glucose deprivation (OGD) (MOI=1:5). Neuronal survival was measured by LDH release. Lentivirus were stereotaxically injected into the cortex, and rats were subjected to focal ischemia induced by distal MCA occlusion combined with bilateral CCA occlusion. Western blotting and immunofluorescent confocal microscopy were used to detect the expression of Akt isoforms and other proteins in both the Akt and mTOR pathways. Results: Western blotting analysis showed that both endogenous Akt1 and 3 proteins degraded as early as 1 h after stroke, while Akt2 protein remained unchanged until 24 h after stroke. In vitro studies showed that over-expression of both constitutively active cAkt1 and cAkt3 decreased LDH release after OGD, while AktDN worsened neuronal death ( P <0.05). In vivo over-expression of cAkt1, cAkt3 and PRAS40 reduced infarct size after stroke ( P <0.01). Gene transfer of cAkt1 and 3 also promoted protein levels of pAkt (phosphorylated Akt), pPRAS40, pFKHR, pPTEN, pmTOR, but not pGSK3β. Both in vitro and in vivo studies showed that over-expression of cAkt3 resulted in a stronger protection than cAkt1 ( P <0.05). Interestingly, cAkt3 gene transfer preserved both endogenous protein levels of Akt1 and 3, whereas cAkt1 gene transfer only preserved endogenous Akt1. Furthermore, cAkt3 promoted higher pmTOR levels than cAkt1. Treatment of rapamycin, an mTOR inhibitor, blocked the protective effects of both cAkt1 and cAkt3 both in vitro and in vivo. Conclusion: Lentiviral-mediated overexpression of cAkt3 confers stronger protection than that of cAkt1, by maintaining both endogenous Akt1 and Akt3, as well as promoting higher mTOR activities after stroke.

scholarly journals Protective Effect of Phillyrin on Lethal LPS-Induced Neutrophil Inflammation in Zebrafish

2017 ◽  
Vol 43 (5) ◽  
pp. 2074-2087 ◽  
Author(s):  
Liling Yang ◽  
Xiangjun Zhou ◽  
Weijuan Huang ◽  
Qin Fang ◽  
Jianlan Hu ◽  
...  
Keyword(s):  
Signalling Pathway ◽  
Dependent Manner ◽  
Zebrafish Model ◽  
Lps Challenge ◽  
Cell Counts ◽  
Tnf Α ◽  
Forsythia Suspensa ◽  
Anti Inflammatory

Background/Aims: Forsythia suspensa Vahl. (Oleaceae) fruits are widely used in traditional Chinese medicine to treat pneumonia, typhoid, dysentery, ulcers and oedema. Antibacterial and anti-inflammatory activities have been reported for phillyrin (PHN), the main ingredient in Forsythia suspensa Vahl fruits, in vitro. However, the underlying mechanisms in vivo remain poorly defined. In this study, we discovered that PHN exerted potent anti-inflammatory effects in lethal LPS-induced neutrophil inflammation by suppressing the MyD88-dependent signalling pathway in zebrafish. Methods: LPS-yolk microinjection was used to induce a lethal LPS-infected zebrafish model. The effect of PHN on the survival of zebrafish challenged with lethal LPS was evaluated using survival analysis. The effect of PHN on neutrophil inflammation grading in vivo was assessed by tracking neutrophils with a transgenic line. The effects of PHN on neutrophil production and migration were analysed by SB+ cell counts during consecutive hours after modelling. Additionally, key cytokines and members of the MyD88 signalling pathway that are involved in inflammatory response were detected using quantitative RT-PCR. To assess gene expression changes during consecutive hours after modelling, the IL-1β, IL-6, TNF-α, MyD88, TRIF, ERK1/2, JNK, IκBa and NF-κB expression levels were measured. Results: PHN could protect zebrafish against a lethal LPS challenge in a dose-dependent manner, as indicated by decreased neutrophil infltration, reduced tissue necrosis and increased survival rates. Up-regulated IL-1β, IL-6 and TNF-α expression also showed the same tendencies of depression by PHN. Critically, PHN significantly inhibited the LPS-induced activation of MyD88, IκBa, and NF-κB but did not affect the expression of ERK1/2 MAPKs or JNK MAPKs in LPS-stimulated zebrafish. Additionally, PHN regulated the MyD88/IκBα/NF-κB signalling pathway by controlling IκBα, IL-1β, IL-6, and TNF-α expression. Conclusion: This study provides a rationale for the clinical application of PHN as an anti-inflammatory agent.

scholarly journals A novel antioxidant ergothioneine PET radioligand for in vivo imaging applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
William J. Behof ◽  
Clayton A. Whitmore ◽  
Justin R. Haynes ◽  
Adam J. Rosenberg ◽  
Mohammed N. Tantawy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mouse Model ◽  
Peripheral Tissues ◽  
Molar Activity ◽  
Model Of Alzheimer’S Disease ◽  
Specific Retention ◽  
5Xfad Mice ◽  
The Brain

AbstractErgothioneine (ERGO) is a rare amino acid mostly found in fungi, including mushrooms, with recognized antioxidant activity to protect tissues from damage by reactive oxygen species (ROS) components. Prior to this publication, the biodistribution of ERGO has been performed solely in vitro using extracted tissues. The aim of this study was to develop a feasible chemistry for the synthesis of an ERGO PET radioligand, [11C]ERGO, to facilitate in vivo study. The radioligand probe was synthesized with identical structure to ERGO by employing an orthogonal protection/deprotection approach. [11C]methylation of the precursor was performed via [11C]CH3OTf to provide [11C]ERGO radioligand. The [11C]ERGO was isolated by RP-HPLC with a molar activity of 690 TBq/mmol. To demonstrate the biodistribution of the radioligand, we administered approximately 37 MBq/0.1 mL in 5XFAD mice, a mouse model of Alzheimer’s disease via the tail vein. The distribution of ERGO in the brain was monitored using 90-min dynamic PET scans. The delivery and specific retention of [11C]ERGO in an LPS-mediated neuroinflammation mouse model was also demonstrated. For the pharmacokinetic study, the concentration of the compound in the serum started to decrease 10 min after injection while starting to distribute in other peripheral tissues. In particular, a significant amount of the compound was found in the eyes and small intestine. The radioligand was also distributed in several regions of the brain of 5XFAD mice, and the signal remained strong 30 min post-injection. This is the first time the biodistribution of this antioxidant and rare amino acid has been demonstrated in a preclinical mouse model in a highly sensitive and non-invasive manner.

scholarly journals Effect of the proinflammatory cytokine TNF-α on intestinal riboflavin uptake: inhibition mediated via transcriptional mechanism(s)

2018 ◽  
Vol 315 (5) ◽  
pp. C653-C663 ◽  
Author(s):  
Kasin Yadunandam Anandam ◽  
Omar A. Alwan ◽  
Veedamali S. Subramanian ◽  
Padmanabhan Srinivasan ◽  
Rubina Kapadia ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Significant Inhibition ◽  
Mrna Levels ◽  
In Vivo Models ◽  
Uptake Inhibition ◽  
Tnf Α ◽  
Vitro Model ◽  
Factor Α

Riboflavin (RF), is essential for normal cellular metabolism/function. Intestinal RF absorption occurs via a specific carrier-mediated process that involves the apical transporter RFVT-3 ( SLC52A3) and the basolateral RFVT-1 (SLC52A1). Previously, we characterized different cellular/molecular aspects of the intestinal RF uptake process, but nothing is known about the effect of proinflammatory cytokines on the uptake event. We addressed this issue using in vitro, ex vivo, and in vivo models. First, we determined the level of mRNA expression of the human (h)RFVT-3 and hRFVT-1 in intestinal tissue of patients with inflammatory bowel disease (IBD) and observed a markedly lower level compared with controls. In the in vitro model, exposing Caco-2 cells to tumor necrosis factor-α (TNF-α) led to a significant inhibition in RF uptake, an effect that was abrogated upon knocking down TNF receptor 1 (TNFR1). The inhibition in RF uptake was associated with a significant reduction in the expression of hRFVT-3 and -1 protein and mRNA levels, as well as in the activity of the SLC52A3 and SLC52A1 promoters. The latter effects appear to involve Sp1 and NF-κB sites in these promoters. Similarly, exposure of mouse small intestinal enteroids and wild-type mice to TNF-α led to a significant inhibition in physiological and molecular parameters of intestinal RF uptake. Collectively, these findings demonstrate that exposure of intestinal epithelial cells to TNF-α leads to inhibition in RF uptake and that this effect is mediated, at least in part, via transcriptional mechanism(s). These findings may explain the significantly low RF levels observed in patients with IBD.

scholarly journals Nerolidol Mitigates Colonic Inflammation: An Experimental Study Using both In Vivo and In Vitro Models

Nutrients ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2032
Author(s):  
Vishnu Raj ◽  
Balaji Venkataraman ◽  
Saeeda Almarzooqi ◽  
Sanjana Chandran ◽  
Shreesh K. Ojha ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
In Vitro Models ◽  
Mrna Levels ◽  
Colonic Inflammation ◽  
Tnf Α ◽  
Cox 2 ◽  
Anti Inflammatory ◽  
Ht 29

Nerolidol (NED) is a naturally occurring sesquiterpene alcohol present in various plants with potent anti-inflammatory effects. In the current study, we investigated NED as a putative anti-inflammatory compound in an experimental model of colonic inflammation. C57BL/6J male black mice (C57BL/6J) were administered 3% dextran sodium sulfate (DSS) in drinking water for 7 days to induce colitis. Six groups received either vehicle alone or DSS alone or DSS with oral NED (50, 100, and 150 mg/kg body weight/day by oral gavage) or DSS with sulfasalazine. Disease activity index (DAI), colonic histology, and biochemical parameters were measured. TNF-α-treated HT-29 cells were used as in vitro model of colonic inflammation to study NED (25 µM and 50 µM). NED significantly decreased the DAI and reduced the inflammation-associated changes in colon length as well as macroscopic and microscopic architecture of the colon. Changes in tissue Myeloperoxidase (MPO) concentrations, neutrophil and macrophage mRNA expression (CXCL2 and CCL2), and proinflammatory cytokine content (IL-1β, IL-6, and TNF-α) both at the protein and mRNA level were significantly reduced by NED. The increase in content of the proinflammatory enzymes, COX-2 and iNOS induced by DSS were also significantly inhibited by NED along with tissue nitrate levels. NED promoted Nrf2 nuclear translocation dose dependently. NED significantly increased antioxidant enzymes activity (Superoxide dismutase (SOD) and Catalase (CAT)), Hemeoxygenase-1 (HO-1), and SOD3 mRNA levels. NED treatment in TNF-α-challenged HT-29 cells significantly decreased proinflammatory chemokines (CXCL1, IL-8, CCL2) and COX-2 mRNA levels. NED supplementation attenuates colon inflammation through its potent antioxidant and anti-inflammatory activity both in in vivo and in vitro models of colonic inflammation.

scholarly journals Regulation of dendritic cell migration and adaptive immune response by leukotriene B4 receptors: a role for LTB4 in up-regulation of CCR7 expression and function

Blood ◽  
2006 ◽  
Vol 109 (2) ◽  
pp. 626-631 ◽  
Author(s):  
Annalisa Del Prete ◽  
Wen-Hai Shao ◽  
Stefania Mitola ◽  
Giuseppe Santoro ◽  
Silvano Sozzani ◽  
...  
Keyword(s):  
Gene Array ◽  
Adaptive Immune Response ◽  
Leukotriene B4 ◽  
Contact Hypersensitivity ◽  
Mrna Levels ◽  
Peripheral Tissues ◽  
Ccr7 Expression ◽  
Adaptive Immune

Abstract Trafficking of dendritic cells (DCs) to peripheral tissues and to secondary lymphoid organs depends on chemokines and lipid mediators. Here, we show that bone marrow–derived DCs (BM-DCs) express functional leukotriene B4 (LTB4) receptors as observed in dose-dependent chemotaxis and calcium mobilization responses. LTB4, at low concentrations, promoted the migration of immature and mature DCs to CCL19 and CCL21, which was associated with a rapid (30-minute) increase of CCR7 expression at the membrane level. At longer incubation times (6 hours), gene array analysis revealed a promoting role of LTB4, showing a significant increase of CCR7 and CCL19 mRNA levels. BM-DCs cultured from BLT1−/− or BLT1/2−/− mice showed a normal phenotype, but in vivo BLT1/2−/−DCs showed dramatic decrease in migration to the draining lymph nodes relative to wild-type (WT) DCs. Consistent with these observations, BLT1/2−/− mice showed a reduced response in a model of 2,4-dinitro-fluorobenzene (DNFB)–induced contact hypersensitivity. Adoptive transfer of 2,4-dinitrobenzene sulfonic acid (DNBS)–pulsed DCs directly implicated the defect in DC migration to lymph node with the defect in contact hypersensitivity. These results provide strong evidence for a role of LTB4 in regulating DC migration and the induction of adaptive immune responses.

Characterization of calves exhibiting a novel inheritable TNF-α hyperresponsiveness to endotoxin: associations with increased pathophysiological complications

2005 ◽  
Vol 98 (6) ◽  
pp. 2045-2055 ◽  
Author(s):  
T. H. Elsasser ◽  
J. W. Blum ◽  
S. Kahl
Keyword(s):  
Mononuclear Cells ◽  
Acute Phase Protein ◽  
Peripheral Blood Mononuclear ◽  
Lps Challenge ◽  
Genetic Potential ◽  
Tnf Α ◽  
Related Stress

A subpopulation of calves, herein termed “hyperresponders” (HPR), was identified and defined by the patterns of plasma TNF-α concentrations that developed following two challenges with endotoxin (LPS, 0.8 μg Escherichia coli 055:B5 LPS/kg0.75live body wt) separated by 5 days. The principle characteristic of HPR calves was a failure to develop tolerance to repeated LPS challenge that was evident in the magnitude of the TNF-α concentrations and prolonged severity of pathological sequellae. Whereas calves failing to develop LPS tolerance were identified on the basis of their excessive in vivo plasma TNF-α concentration responses, in vitro TNF-α responses of peripheral blood mononuclear cells isolated from each calf and challenged with LPS or PMA did not correlate or predict the magnitude of in vivo plasma TNF response of the calf. Intentional breeding to obtain calves from bulls and/or cows documented as HPR resulted in offspring displaying the HPR character when similar progeny calves were tested with LPS in vivo, with extensive controls in place to account for sources of variability in the general TNF-α response to LPS that might compromise interpretation of the data. Feed intake, clinical serology and hematology profiles, and acute-phase protein responses of HPR calves following LPS were significantly different from those of calves displaying tolerance. These results suggest that the pattern of plasma TNF-α changes that evolve from a low-level double LPS challenge effectively reveal the presence of a genetic potential for animals to display excessive or prolonged pathological response to LPS-related stress and compromised prognosis for recovery.

Acute Lung Inflammation in Sickle Mice Is Mediated by Increase of CXC Chemokines and Matrix Metalloproteinases

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2483-2483
Author(s):  
Carla Fernanda Franco-Penteado ◽  
Carolina Lanaro ◽  
Dulcinéia M Albuquerque ◽  
Ana Paula Gimenes ◽  
Luiz Augusto C Passos ◽  
...  
Keyword(s):  
Matrix Metalloproteinases ◽  
Lung Inflammation ◽  
Intranasal Administration ◽  
Pcr Analysis ◽  
Acute Chest Syndrome ◽  
Control Group ◽  
Mrna Levels ◽  
Acute Lung Inflammation ◽  
Lps Challenge ◽  
Tnf Α

Abstract Studies in vitro, and in vivo using animal models show that leukocytes play a key role in vasoocclusion and clinical research suggests that high leukocyte counts correlate with mortality, stroke and acute chest syndrome in sickle cell disease (SCD). Lungs are particularly vulnerable to vaso-occlusive events because of their anatomic features in SCD. Transgenic mice expressing exclusively human sickle hemoglobin (SS) are well-established models for the study of vascular inflammation. Previous studies have shown that systemic LPS challenge causes exaggerated inflammation, including increased serum and broncoalveolar lavage (BAL) TNF-α and IL-1 cytokines and sVCAM-1 in sickle mice. The aim of this study was to examine the contribution of acute airway inflammation in SCD using SS mice and the role of chemokines and matrix metalloproteinases (MMPs) in this process. Acute lung inflammation and injury were induced by intranasal administration of lipopolysaccharide (LPS, 50 μl of 250 μg/ml) in control (C57BL/6) and SS mice. The vehicle mice group received a similar volume of sterile PBS. BAL was performed 4 h after LPS challenge. qRT-PCR analysis was used to examine gene expression and ELISA protein production. The intranasal administration of LPS to mice triggered a huge influx of leukocytes (neutrophils, NS) in BAL of control and SS mice compared with the respective vehicle groups, but this influx was greater in SS mice, when compared with control mice (1.4 ± 0.06 vs 0.66 ± 0.12 WBCx106/BAL); p=0.0006, 1.06 ± 0.1 vs 0.40 ±0.12 NSx106/BAL; p=0.004, respectively). At baseline levels, KC and MIP-2 chemokines (functional homologues of human IL-8 in mice) are higher in BAL fluid of SS mice compared to control mice (186.6 ± 14.1 pg/ml vs 14.1 ± 5.8 pg/ml; 41.2 ± 7.9 pg/ml vs 11.4 ± 7.3 pg/ml, p=, respectively). Corresponding with influx of NS, lung lavage levels of KC and MIP-2 were significantly higher in SS BALF compared to control mice (2491 ± 454 pg/ml vs 798.1 vs 98.2 pg/ml; 1726 ± 307 pg/ml vs 887.3 ± 149.5 pg/ml, respectively). Enhanced levels of TNF-α were also observed at baseline and after LPS instillation compared to those of the control mice (20.8 ± 8.8 pg/ml vs 2.5 ± 1.6 pg/ml; 4250 ± 636 pg/ml vs 1585 ± 263 pg/ml, respectively). Instillation of LPS markedly increased KC, TNF-α, MMP-8, MMP-9 and TIMP-1 mRNA levels in the lungs of control and SS mice compared to animals that received PBS instead of LPS (Control, KC: 0.19 ± 0.047 vs 0.01 ± 0.005; TNF-α: 0.30 ± 0.07 vs 0.01 ± 0.002; MMP-8: 0.2 ± 0.06 vs 0.016 ± 0.004; MMP-9: 0.22 ± 0.03 vs 0.08 ± 0.01; TIMP-1: 0.32 ± 0.06 vs 0.09 ± 0.03); (SS, KC: 0.42 ± 0.1 vs 0.039 ± 0.02; TNF-α: 0.23 ± 0.025 vs 0.02 ± 0.007; MMP-8: 0.42 ± 0.06 vs 0.06 ± 0.03; MMP-9: 0.49 ± 0.11 vs 0.11 ± 0.05; TIMP-1: 0.49 ± 0.11 vs 0.09 ± 0.03). However, the LPS-induced KC, MMP-8 and MMP-9 expression was significantly higher in SS mice lung compared than that of the control group (p&lt;0.05). Lung MMP-2, MMP-12 and TIMP-2 gene expressions were similar in the PBS and LPS groups and were not significantly different between SS and control mice. Our results indicate that chemokines and MMPs are critically involved in the recruitment of neutrophils to the lung following LPS challenge, and suggest that these inflammatory mediators may play a role in the development of pulmonary diseases in SCD. The findings from this study provide further support to the claim that a proinflammatory state is present in SCD and have important implications for the pathophysiology of lung injury in SCD.

A realistic brain tissue phantom for intraparenchymal infusion studies

2004 ◽  
Vol 101 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Zhi-Jian Chen ◽  
George T. Gillies ◽  
William C. Broaddus ◽  
Sujit S. Prabhu ◽  
Helen Fillmore ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Bromophenol Blue ◽  
Agarose Gel ◽  
Convection Enhanced Delivery ◽  
Content Type ◽  
Force Profile ◽  
The Brain ◽  
Fine Print

Object. The goal of this study was to validate a simple, inexpensive, and robust model system to be used as an in vitro surrogate for in vivo brain tissues in preclinical and exploratory studies of infusion-based intraparenchymal drug and cell delivery. Methods. Agarose gels of varying concentrations and porcine brain were tested to determine the infusion characteristics of several different catheters at flow rates of 0.5 and 1 µl per minute by using bromophenol blue (BPB) dye (molecular weight [MW] ∼690) and gadodiamide (MW ∼573). Magnetic resonance (MR) imaging and videomicroscopy were used to measure the distribution of these infusates, with a simultaneous measurement of infusion pressures. In addition, the forces of catheter penetration and movement through gel and brain were measured. Agarose gel at a 0.6% concentration closely resembles in vivo brain with respect to several critical physical characteristics. The ratio of distribution volume to infusion volume of agarose was 10 compared with 7.1 for brain. The infusion pressure of the gel demonstrated profiles similar in configuration and magnitude to those of the brain (plateau pressures 10–20 mm Hg). Gadodiamide infusion in agarose closely resembled that in the brain, as documented using T1-weighted MR imaging. Gadodiamide distribution in agarose gel was virtually identical to that of BPB dye, as documented by MR imaging and videomicroscopy. The force profile for insertion of a silastic catheter into agarose gel was similar in magnitude and configuration to the force profile for insertion into the brain. Careful insertion of the cannula using a stereotactic guide is critical to minimize irregularity and backflow of infusate distribution. Conclusions. Agarose gel (0.6%) is a useful surrogate for in vivo brain in exploratory studies of convection-enhanced delivery.

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