A Novel Ex Vivo Heart Model for the Assessment of Cardiac Pacing Systems

2005 ◽  
Vol 127 (6) ◽  
pp. 894-898 ◽  
Author(s):  
Timothy G. Laske ◽  
Nicholas D. Skadsberg ◽  
Paul A. Iaizzo
Keyword(s):  
Ex Vivo ◽  
Isolated Heart ◽  
Cardiac Pacing ◽  
P Wave ◽  
Tissue Interface ◽  
The Right ◽  
Endocardial Pacing ◽  
The Impact ◽  
Heart Apparatus

Background: Advances in endocardial device design have been limited by the inability to visualize the device-tissue interface. The purpose of this study was to assess the validity of an isolated heart approach, which allows direct ex vivo intracardiac visualization, as a research tool for studying endocardial pacing systems. Method of approach: Endocardial pacing leads were implanted in the right atria and ventricles of intact swine (n=8) under fluoroscopic guidance. After collection of pacing and sensing performance parameters, the hearts were excised with the leads intact and reanimated on the isolated heart apparatus, and parameters again recorded. Results: Atrial ex vivo parameters significantly decreased compared with in vivo measurements: P-wave amplitudes by 39%, slew rates by 61%, and pacing impedances by 42% (p<0.05 for each). Similarly, several ventricular ex vivo parameters decreased: R-wave amplitudes by 39%, slew rates by 62%, and pacing impedances by 31%. In contrast, both atrial (4.4±2.8 vs 3.3±2.8V; p=ns) and ventricular thresholds increased (1.2±0.7 vs 0.6±0.1V; p<0.05 for all). Three distinct phenomena were observed at the lead-tissue interface. Normal implants (70%) demonstrated minimal tissue distortion and resulted in elevated impedance and threshold values. Three implants (13%) resulted in severe tissue distortion and/or tissue wrapping and were associated with highly elevated pacing parameters. Tissue coring occurred in four implants (17%) where the lead would spin freely in the tissue after overtorquing of the lead. Conclusions: The utility of the isolated heart approach was demonstrated as a tool for the design and assessment of the performance of endocardial pacing systems. Specifically, the ability to visualize device-heart interactions allows new insights into the impact of product design and clinical factors on lead performance and successful implantation.

scholarly journals Histological, Biomechanical, and Biological Properties of Genipin-Crosslinked Decellularized Peripheral Nerves

2021 ◽  
Vol 22 (2) ◽  
pp. 674
Author(s):  
Óscar Darío García-García ◽  
Marwa El Soury ◽  
David González-Quevedo ◽  
David Sánchez-Porras ◽  
Jesús Chato-Astrain ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Nerve Repair ◽  
Wistar Rat ◽  
Biomechanical Properties ◽  
Biological Properties ◽  
Suitable Alternative ◽  
Promising Alternative ◽  
Histological Pattern ◽  
The Impact

Acellular nerve allografts (ANGs) represent a promising alternative in nerve repair. Our aim is to improve the structural and biomechanical properties of biocompatible Sondell (SD) and Roosens (RS) based ANGs using genipin (GP) as a crosslinker agent ex vivo. The impact of two concentrations of GP (0.10% and 0.25%) on Wistar rat sciatic nerve-derived ANGs was assessed at the histological, biomechanical, and biocompatibility levels. Histology confirmed the differences between SD and RS procedures, but not remarkable changes were induced by GP, which helped to preserve the nerve histological pattern. Tensile test revealed that GP enhanced the biomechanical properties of SD and RS ANGs, being the crosslinked RS ANGs more comparable to the native nerves used as control. The evaluation of the ANGs biocompatibility conducted with adipose-derived mesenchymal stem cells cultured within the ANGs confirmed a high degree of biocompatibility in all ANGs, especially in RS and RS-GP 0.10% ANGs. Finally, this study demonstrates that the use of GP could be an efficient alternative to improve the biomechanical properties of ANGs with a slight impact on the biocompatibility and histological pattern. For these reasons, we hypothesize that our novel crosslinked ANGs could be a suitable alternative for future in vivo preclinical studies.

scholarly journals Ex Vivo Mitochondrial Respiration Parallels Biochemical Response to Ibrutinib in CLL Cells

Cancers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 354
Author(s):  
Subir Roy Chowdhury ◽  
Cheryl Peltier ◽  
Sen Hou ◽  
Amandeep Singh ◽  
James B. Johnston ◽  
...  
Keyword(s):  
Mitochondrial Respiration ◽  
Ex Vivo ◽  
Standard Dose ◽  
Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Clinical Tool ◽  
Potential Biomarker ◽  
Apoptotic Pathways ◽  
The Impact

Mitochondrial respiration is becoming more commonly used as a preclinical tool and potential biomarker for chronic lymphocytic leukemia (CLL) and activated B-cell receptor (BCR) signaling. However, respiration parameters have not been evaluated with respect to dose of ibrutinib given in clinical practice or the effect of progression on ibrutinib treatment on respiration of CLL cells. We evaluated the impact of low and standard dose ibrutinib on CLL cells from patients treated in vivo on mitochondrial respiration using Oroboros oxygraph. Cytokines CCL3 and CCL4 were evaluated using the Mesoscale. Western blot analysis was used to evaluate the BCR and apoptotic pathways. We observed no difference in the mitochondrial respiration rates or levels of plasma chemokine (C-C motif) ligands 3 and 4 (CCL3/CCL4), β-2 microglobulin (β-2 M) and lactate dehydrogenase (LDH) between low and standard doses of ibrutinib. This may confirm why clinical observations of the safety and efficacy of low dose ibrutinib are observed in practice. Of interest, we also observed that the mitochondrial respiration of CLL cells paralleled the increase in β-2 M and LDH at progression. Our study further supports mitochondrial respiration as a biomarker for response and progression on ibrutinib in CLL cells and a valuable pre-clinical tool.

scholarly journals PD-L1 Checkpoint Blockade Augments Anti-Tumor Immune Response of GD2 or HER2-Bsab Ex Vivo Armed T-Cells (EVAT) Therapy in Osteosarcoma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1959-1959
Author(s):  
Jeong A Park ◽  
Hong fen Guo ◽  
Hong Xu ◽  
Nai-Kong V. Cheung
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Immune Checkpoint ◽  
Bispecific Antibody ◽  
Ex Vivo ◽  
Activated T Cells ◽  
The Impact ◽  
Anti Tumor Activity

Background Ex Vivo Armed T-cells (EVAT) carrying zeptomoles (10-21M) of T-cell engaging GD2-bispecific antibody (GD2-EVAT) or HER2-bispecific antibodies (HER2-EVAT) have potent anti-tumor activity against GD2(+) and/or HER2(+) solid tumors. Strategies to further optimize this approach are highly relevant. PD-1 is a key immune checkpoint receptor expressed mainly by activated T-cells and mediates immune suppression by binding to its ligands PD-L1 or PD-L2. Upregulation of PD-L1 has been found in many cancers including osteosarcoma and associated with aggressive disease and poor outcome. While the use of immune checkpoint inhibitors (ICIs) seems logical, the ideal timing when combined with T-cell engaging bispecific antibody (T-BsAb) or EVAT has yet to be defined. Here, we described the effects of anti-PD-1 or anti-PD-L1 antibodies on GD2-EVAT or HER2-EVAT therapy and explored the impact of its timing in the treatment of osteosarcoma which is GD2(+), HER2(+) and PD-L1(+). Methods GD2-BsAb and HER-BsAb were built using the IgG(L)-scFv format (Can Immunol Res, 3:266, 2015, Oncoimmunology, PMID:28405494). T-cells from healthy volunteer donors were isolated, and cultured ex vivo in the presence of CD3/CD28 beads plus 30 IU/mL of interleukin 2 (IL-2). Between day 7 and day 14, activated T-cells (ATCs) were harvested and armed for 20 minutes at room temperature with GD2-BsAb or HER2-BsAb. In vivo anti-tumor activity against GD2(+), HER2(+), and PD-L1(+) osteosarcoma cell line xenografts was tested in BALB-Rag2-/-IL-2R-γc-KO mice. Anti-human PD-1 antibody (pembrolizumab, anti-PD-1) or anti-human PD-L1 antibody (atezolizumab, anti-PD-L1) were tested for synergy with GD2-EVAT or HER2-EVAT therapy. Results The PD-1 expression increased among T-cells that circulated in the blood, that infiltrated the spleen or the tumor after EVAT therapy. While anti-PD-L1 combination therapy with GD2-EVAT or HER2-EVAT improved anti-tumor response against osteosarcoma (P=0.0123 and P=0.0004), anti-PD-1 did not (all P>0.05). The addition of anti-PD-L1 significantly increased T-cell survival in blood and T-cell infiltration of tumor when compared to GD2-EVAT or HER2-EVAT alone (all P<0.0001). Treatment of GD2-EVAT or anti-PD-L1 plus GD2-EVAT downregulated GD2 expression on tumors, but anti-PD-1 plus GD2-EVAT did not. For the next step we tested the impact of different combination schedules of ICIs on GD2-EVAT therapy. Concurrent anti-PD-1 (6 doses along with GD2-EVAT therapy) interfered with GD2-EVAT, while sequential anti-PD-1 (6 doses after GD2-EVAT) did not make a significant effect (P>0.05). On the other hand, while the concurrent use of anti-PD-L1 did not show benefit on GD2-EVAT, sequentially administered anti-PD-L1 produced a significant improvement in tumor control when compared to anti-PD-L1 or GD2-EVAT alone (P=0.002 and P=0.018). When anti-PD-L1 treatment was extended (12 doses after GD2-EVAT), the anti-tumor effect was most pronounced compared to GD2-EVAT alone (P <0.0001), which translated into improved survival (P=0.0057). These in vivo anti-tumor responses were associated with increased CD8(+) tumor infiltrating lymphocytes (TILs) of tumor. Conclusion In the arming platform, large numbers of target-specific T-cells can be generated, and this EVAT therapy is a highly effective cellular treatment with high potency in preclinical models. In addition, the advantage of ex vivo cytokine release following T-cell arming and activation could reduce or avoid life threatening cytokine storm if such activation was to proceed in vivo. Adoptive T-cell therapy induced immune response upregulates the inhibitory immune checkpoint PD-1/PD-L1 pathway, and combination treatment with anti-PD-L1 antibody, especially when combined as sequential therapy and continuously treated, significantly improved anti-tumor effect of EVAT, partly through increase in CD8(+) TILs infiltration. Disclosures Xu: MSK: Other: co-inventors in patents on GD2 bispecific antibody and HER2 bispecific antibody. Cheung:Ymabs: Patents & Royalties, Research Funding.

Abstract 401: Experimental Aneurysm in Rats Excluded by Stent Graft: A New Model to Assess the Impact of Endovascular Aneurysm Repair on the Pathophysiology of Abdominal Aortic Aneurysm.

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Martin Rouer ◽  
Martin Rouer ◽  
Jean-Marc Alsac ◽  
Jean-Baptiste Michel
Keyword(s):  
Experimental Model ◽  
Ex Vivo ◽  
Endovascular Aneurysm Repair ◽  
Small Animal ◽  
Normal Diet ◽  
Biological Study ◽  
Experimental Aneurysm ◽  
Midline Laparotomy ◽  
The Impact

Introduction Biological study of the impact of endovascular aortic repair (EVAR) on pathophysiology of aortic abdominal aneurysms (AAA) can only be performed indirectly in humans, by imaging or search for peripheral biomarkers in the circulating blood. Therefore biological mechanism’s modifications into the aneurismal wall related to its endovascular exclusion are still to be elucidated, and small animal models should bring a valuable help in this field. We describe a new experimental model of stentgraft implantation for the exclusion of AAA in rats. Methods Aneurysms were induced as previously described by intra-aortic elastase injection in Wistar rats, or by aortic decellularized xenograft transplantation in Lewis rats. At least 15 days later, the midline laparotomy was reopened, and 3mm covered stentgraft were inserted and deployed in the AAA to obtain its exclusion. The patency of the graft and the AAA exclusion could be assessed by a global arteriogram through the carotid artery. After closure of the laparotomy, the rats were awakened and returned to a normal diet. Results This experimental model of AAA exclusion by a stentgraft allows many in vivo and ex vivo studies of the pathophysiology of AAA after EVAR. Histological modifications of the aortic wall and the intra-luminal thrombus could be assessed. The impact of EVAR on the adventitial immuno-inflammatory activity could be studied by different imaging such as MRI, scintigraphy or PET-scan. In situ biological and enzymatic activities could be evaluated to better understand the local mechanisms leading to AAA shrinkage or expansion after EVAR. Conclusion Exclusion by stentgraft of experimental AAA in rats is the first described model of EVAR in small animals. It is feasible and reproducible for both elastase and xenograft experimental AAA models. This model will definitely help to a better analysis and understanding of the impact of stentgrafting on biological mechanisms in the aneurismal wall, that lead to EVAR success with shrinkage of aneurismal sac or EVAR failure with its continuing expansion.

scholarly journals Intestinal IgA Regulates Expression of a Fructan Polysaccharide Utilization Locus in Colonizing Gut Commensal Bacteroides thetaiotaomicron

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Payal Joglekar ◽  
Hua Ding ◽  
Pablo Canales-Herrerias ◽  
Pankaj Jay Pasricha ◽  
Justin L. Sonnenburg ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Ex Vivo ◽  
Microbial Colonization ◽  
Bacteroides Thetaiotaomicron ◽  
Content Type ◽  
Microbial Utilization ◽  
Polysaccharide Utilization Locus ◽  
The Impact

ABSTRACT Gut-derived immunoglobulin A (IgA) is the most abundant antibody secreted in the gut that shapes gut microbiota composition and functionality. However, most of the microbial antigens targeted by gut IgA remain unknown, and the functional effects of IgA targeting these antigens are currently understudied. This study provides a framework for identifying and characterizing gut microbiota antigens targeted by gut IgA. We developed a small intestinal ex vivo culture assay to harvest lamina propria IgA from gnotobiotic mice, with the aim of identifying antigenic targets in a model human gut commensal, Bacteroides thetaiotaomicron VPI-5482. Colonization by B. thetaiotaomicron induced a microbe-specific IgA response that was reactive against diverse antigens, including capsular polysaccharides, lipopolysaccharides, and proteins. IgA against microbial protein antigens targeted membrane and secreted proteins with diverse functionalities, including an IgA specific against proteins of the polysaccharide utilization locus (PUL) that are necessary for utilization of fructan, which is an important dietary polysaccharide. Further analyses demonstrated that the presence of dietary fructan increased the production of fructan PUL-specific IgA, which then downregulated the expression of fructan PUL in B. thetaiotaomicron, both in vivo and in vitro. Since the expression of fructan PUL has been associated with the ability of B. thetaiotaomicron to colonize the gut in the presence of dietary fructans, our work suggests a novel role for gut IgA in regulating microbial colonization by modulating their metabolism. IMPORTANCE Given the significant impact that gut microbes have on our health, it is essential to identify key host and environmental factors that shape this diverse community. While many studies have highlighted the impact of diet on gut microbiota, little is known about how the host regulates this critical diet-microbiota interaction. In our present study, we discovered that gut IgA targeted a protein complex involved in the utilization of an important dietary polysaccharide: fructan. While the presence of dietary fructans was previously thought to allow unrestricted growth of fructan-utilizing bacteria, our work shows that gut IgA, by targeting proteins responsible for fructan utilization, provides the host with tools that can restrict the microbial utilization of such polysaccharides, thereby controlling their growth.

scholarly journals EZH2 inhibition reduces cartilage loss and functional impairment related to osteoarthritis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lyess Allas ◽  
Sybille Brochard ◽  
Quitterie Rochoux ◽  
Jules Ribet ◽  
Cleo Dujarrier ◽  
...  
Keyword(s):  
Functional Disability ◽  
Ex Vivo ◽  
Cartilage Degradation ◽  
Motor Functions ◽  
Methyl Transferase ◽  
Expression Of Genes ◽  
Medial Meniscectomy ◽  
The Impact

Abstract Histone methyltransferase EZH2 is upregulated during osteoarthritis (OA), which is the most widespread rheumatic disease worldwide, and a leading cause of disability. This study aimed to assess the impact of EZH2 inhibition on cartilage degradation, inflammation and functional disability. In vitro, gain and loss of EZH2 function were performed in human articular OA chondrocytes stimulated with IL-1β. In vivo, the effects of EZH2 inhibition were investigated on medial meniscectomy (MMX) OA mouse model. The tissue alterations were assayed by histology and the functional disabilities of the mice by actimetry and running wheel. In vitro, EZH2 overexpression exacerbated the action of IL-1β in chondrocytes increasing the expression of genes involved in inflammation, pain (NO, PGE2, IL6, NGF) and catabolism (MMPs), whereas EZH2 inhibition by a pharmacological inhibitor, EPZ-6438, reduced IL-1β effects. Ex vivo, EZH2 inhibition decreased IL-1β-induced degradation of cartilage. In vivo, intra-articular injections of the EZH2 inhibitor reduced cartilage degradation and improved motor functions of OA mice. This study demonstrates that the pharmacological inhibition of the histone methyl-transferase EZH2 slows the progression of osteoarthritis and improves motor functions in an experimental OA model, suggesting that EZH2 could be an effective target for the treatment of OA by reducing catabolism, inflammation and pain.

Activation of a Classic Hunger Circuit Slows Luteinizing Hormone Pulsatility

2019 ◽  
Vol 110 (7-8) ◽  
pp. 671-687 ◽  
Author(s):  
Eulalia A. Coutinho ◽  
Melanie Prescott ◽  
Sabine Hessler ◽  
Christopher J. Marshall ◽  
Allan E. Herbison ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Ex Vivo ◽  
Polycystic Ovary ◽  
Brain Slices ◽  
Pulse Frequency ◽  
Pulse Generation ◽  
Electrophysiological Studies ◽  
The Impact ◽  
Lh Secretion

Introduction: The central regulation of fertility is carefully coordinated with energy homeostasis, and infertility is frequently the outcome of energy imbalance. Neurons in the hypothalamus expressing neuropeptide Y and agouti-related peptide (NPY/AgRP neurons) are strongly implicated in linking metabolic cues with fertility regulation. Objective: We aimed here to determine the impact of selectively activating NPY/AgRP neurons, critical regulators of metabolism, on the activity of luteinizing hormone (LH) pulse generation. Methods: We employed a suite of in vivo optogenetic and chemogenetic approaches with serial measurements of LH to determine the impact of selectively activating NPY/AgRP neurons on dynamic LH secretion. In addition, electrophysiological studies in ex vivo brain slices were employed to ascertain the functional impact of activating NPY/AgRP neurons on gonadotropin-releasing hormone (GnRH) neurons. Results: Selective activation of NPY/AgRP neurons significantly decreased post-castration LH secretion. This was observed in males and females, as well as in prenatally androgenized females that recapitulate the persistently elevated LH pulse frequency characteristic of polycystic ovary syndrome (PCOS). Reduced LH pulse frequency was also observed when optogenetic stimulation was restricted to NPY/AgRP fiber projections surrounding GnRH neuron cell bodies in the rostral preoptic area. However, electrophysiological studies in ex vivo brain slices indicated these effects were likely to be indirect. Conclusions: These data demonstrate the ability of NPY/AgRP neuronal signaling to modulate and, specifically, reduce GnRH/LH pulse generation. The findings suggest a mechanism by which increased activity of this hunger circuit, in response to negative energy balance, mediates impaired fertility in otherwise reproductively fit states, and highlight a potential mechanism to slow LH pulsatility in female infertility disorders, such as PCOS, that are associated with hyperactive LH secretion.

“The Balloon Plug Concept” for Tricuspid Valve Repair Ex Vivo Proof of Concept

2015 ◽  
Vol 10 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Pietro Bajona ◽  
Stefano Salizzoni ◽  
Stijn Vandenberghe ◽  
Charles J. Bruce ◽  
Giovanni Speziali ◽  
...  
Keyword(s):  
Tricuspid Regurgitation ◽  
Ex Vivo ◽  
Tricuspid Valve Repair ◽  
Functional Tricuspid Regurgitation ◽  
Novel Approach ◽  
Annular Dilatation ◽  
Transvalvular Gradient ◽  
Antegrade Flow ◽  
The Right

Objective Functional tricuspid regurgitation (TR) is recognized as a significant cause of morbidity and mortality in cardiothoracic surgery. We hypothesized that a variably expandable, transvalvular balloon mounted on a catheter could be percutaneously inserted and fixed to the right ventricle apex. This novel approach could provide a minimally invasive way to eliminate clinically relevant TR caused by annular dilatation. This study was performed to test the ex vivo hemodynamic effects and the feasibility of the “balloon plug concept.” Methods Twenty harvested calf tricuspid valves were placed in a mechanical simulator. Tricuspid regurgitation was created by annular stretching and displacement of the papillary muscles so as to create central TR. A flexible catheter with a 4-cm–long, soft, fusiform balloon was positioned across the valve so that the balloon was suspended centrally across the valve annular plane. After activating the mechanical ventricle, data were collected with balloon inflation volumes of saline from 5 to 20 mL. Transvalvular pressure gradients and leaflet mechanics were evaluated with incremental inflation. Results In all cases, 5-mL inflation did not significantly reduce TR and 20-mL inflation caused obstruction to antegrade flow (mean transvalvular gradient > 4 mm Hg). Inflation between 10 and 15 mL caused significant reduction in TR with acceptable transvalvular gradients (<3 mm Hg). Conclusions The balloon plug concept showed promising ex vivo hemodynamic results. In vivo investigations are warranted to evaluate percutaneous techniques, thrombogenicity, and effects of repeated balloon-leaflet contact on valve integrity.

Naive and Ex Vivo Activated Human T Cells Generate Consistent Engraftment and Lethal Graft-Versus-Host Disease (GvHD) in NOD SCID β 2M Null Mice: A New Xenogeneic Model for GvHD.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3106-3106
Author(s):  
Bruno Nervi ◽  
Michael P. Rettig ◽  
Julie K. Ritchey ◽  
Gerhard Bauer ◽  
Jon Walker ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
Conditioning Regimen ◽  
Activation Markers ◽  
In Vivo Models ◽  
Hematopoietic Stem ◽  
Human T Cells ◽  
The Impact

Abstract GvHD remains a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation and donor lymphocyte infusion. The human GvHD pathophysiology includes recipient tissue destruction and proinflammatory cytokine production associated with the conditioning regimen; donor T cells become allo-activated, proliferate, and mediate tissue injury in various organs, including the liver, skin, and gut. Modern therapeutic strategies to control GvHD while maintaining the beneficial graft-versus-leukemia effects require ex vivo T cell stimulation and expansion. Multiple studies have demonstrated that these ex vivo expanded T cells exhibit decreased survival and function in vivo, including reduced alloreactivity and GvHD potential. Unfortunately no in vivo models exist to consistently examine the impact of ex vivo manipulation of human T cells (HuT) on T cell function. Naive HuT were compared to HuT activated using CD3/28 beads (XcyteTMDynabeads) with 50 U/ml IL-2 for 4 days (Act). We initially evaluated the HuT engraftment and GvHD potential of naive and Act in RAG2γ null mice (n=22) conditioned with clodronate liposomes on day −1 and 350cGy on day 0, as previously described by others. We injected 107 and 1.5x107 naive or Act HuT intravenously (iv). All mice exhibited low HuT engraftment and no lethal GvHD. NOD SCIDβ 2M null mice (β 2M) were next conditioned with 250cGy on day −1 (n=34), or 300cGy on day 0 (n=21). 107 naive vs Act HuT were injected retroorbitaly (ro). Lower HuT doses or iv injection resulted in no expansion or GvHD. Engraftment of HuT in peripheral blood of recipient mice was evaluated weekly by FACS and euthanasia was performed if mice lost &gt; 20% body weight. 60% of the mice conditioned with 250cGy that received naive HuT developed lethal GvHD, in comparison to 75% of mice that received 300cGy and nave HuT, and 100% of mice that received 300cGy and Act HuT. Table 1 250cGy 300cGy Naive (n=34) Naive (n=8) Activated (n=13) *p&lt;0.02 PB engraftment (%HuT) 20%±15 33%±21 59%±19 Lethal GvHD 60% 75% 100% All mice receiving 300cGy had well preserved CD4/CD8 ratios (1–1.5). Tissue infiltration was greatest in mice that had received 300cGy and Act HuT (spleen, liver, lung, kidney: 50–70%). Of interest, serum levels of hu IFNγ dramatically increased over time in all mice who went on to develop lethal GvHD (day 3=270 ug/ml and day 15=36,000 ug/ml) compared to mice that did not develop lethal GvHD (day 10=40 ug/ml and day 17=1,020 ug/ml)(p&lt;0.05). Interestingly, the up-regulation of the activation markers CD25 and CD30 in HuT, and IFNγ production predicted lethal GvHD in β 2M null mice. In summary, we developed a xenogeneic model of lethal GvHD where naive or ex vivo Act HuT injected ro in sublethaly irradiated β 2M not only engraft, expand in vivo, but also infiltrate and damage different mouse target organs. HuT are allo-activated against mouse antigens and damage the target tissues, sharing the major characteristics of human GvHD and causing the death of mice. This model will allow us to study the effects of specific ex vivo T cell manipulation including transduction, selection, expansion, and the depletion or addition of various T cells and other cellular subsets on the outcome of GvHD, to determine improved therapeutic interventions.

scholarly journals MR imaging of model drug distribution in simulated vitreous

2015 ◽  
Vol 1 (1) ◽  
pp. 236-239 ◽  
Author(s):  
Sandra Stein ◽  
Christian Simroth-Loch ◽  
Sönke Langner ◽  
Stefan Hadlich ◽  
Oliver Stachs ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ex Vivo ◽  
Drug Distribution ◽  
Injection Technique ◽  
Innovative Therapy ◽  
Age Related ◽  
The Impact

AbstractThe in vitro and in vivo characterization of intravitreal injections plays an important role in developing innovative therapy approaches. Using the established vitreous model (VM) and eye movement system (EyeMoS) the distribution of contrast agents with different molecular weight was studied in vitro. The impact of the simulated age-related vitreal liquefaction (VL) on drug distribution in VM was examined either with injection through the gel phase or through the liquid phase. For comparison the distribution was studied ex vivo in the porcine vitreous. The studies were performed in a magnetic resonance (MR) scanner. As expected, with increasing molecular weight the diffusion velocity and the visual distribution of the injected substances decreased. Similar drug distribution was observed in VM and in porcine eye. VL causes enhanced convective flow and faster distribution in VM. Confirming the importance of the injection technique in progress of VL, injection through gelatinous phase caused faster distribution into peripheral regions of the VM than following injection through liquefied phase. VM and MR scanner in combination present a new approach for the in vitro characterization of drug release and distribution of intravitreal dosage forms.

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