Ultrasound-enhanced delivery of targeted echogenic liposomes in a novel ex vivo mouse aorta model.

J Control Release. 2010 Mar 1;

Authors: Hitchcock KE, Caudell DN, Sutton JT, Klegerman ME, Vela D, Pyne-Geithman GJ, Abruzzo T, Cyr PE, Geng YJ, McPherson DD, Holland CK

The goal of this study was to determine whether targeted, Rhodamine-labeled echogenic liposomes (Rh-ELIP) containing nanobubbles could be delivered to the arterial wall, and whether 1MHz continuous wave ultrasound would enhance this delivery profile. Aortae excised from apolipoprotein-E-deficient (n=8) and wild-type (n=8) mice were mounted in a pulsatile flow system through which Rh-ELIP were delivered in a stream of bovine serum albumin. Half the aortae from each group were treated with 1-MHz continuous wave ultrasound at 0.49MPa peak-to-peak pressure, and half underwent sham exposure. Ultrasound parameters were chosen to promote stable cavitation and avoid inertial cavitation. A broadband hydrophone was used to monitor cavitation activity. After treatment, aortic sections were prepared for histology and analyzed by an individual blinded to treatment conditions. Delivery of Rh-ELIP to the vascular endothelium was observed, and subendothelial penetration of Rh-ELIP was present in five of five ultrasound-treated aortae and was absent in those not exposed to ultrasound. However, the degree of penetration in the ultrasound-exposed aortae was variable. There was no evidence of ultrasound-mediated tissue damage in any specimen. Ultrasound-enhanced delivery within the arterial wall was demonstrated in this novel model, which allows quantitative evaluation of therapeutic delivery.

PMID: 20202474 [PubMed - as supplied by publisher]

IFN-{beta} Restricts Tumor Growth and Sensitizes Alveolar Rhabdomyosarcoma to Ionizing Radiation.

Mol Cancer Ther. 2010 Mar 2;

Authors: Sims TL, McGee M, Williams RF, Myers AL, Tracey L, Hamner JB, Ng C, Wu J, Gaber MW, McCarville B, Nathwani AC, Davidoff AM

Ionizing radiation is an important component of multimodal therapy for alveolar rhabdomyosarcoma (ARMS). We sought to evaluate the ability of IFN-beta to enhance the activity of ionizing radiation. Rh-30 and Rh-41 ARMS cells were treated with IFN-beta and ionizing radiation to assess synergistic effects in vitro and as orthotopic xenografts in CB17 severe combined immunodeficient mice. In addition to effects on tumor cell proliferation and xenograft growth, changes in the tumor microenvironment including interstitial fluid pressure, perfusion, oxygenation, and cellular histology were assessed. A nonlinear regression model and isobologram analysis indicated that IFN-beta and ionizing radiation affected antitumor synergy in vitro in the Rh-30 cell line; the activity was additive in the Rh-41 cell line. In vivo continuous delivery of IFN-beta affected normalization of the dysfunctional tumor vasculature of both Rh-30 and Rh-41 ARMS xenografts, decreasing tumor interstitial fluid pressure, increasing tumor perfusion (as assessed by contrast-enhanced ultrasonography), and increasing oxygenation. Tumors treated with both IFN-beta and radiation were smaller than control tumors and those treated with radiation or IFN-beta alone. Additionally, treatment with high-dose IFN-beta followed by radiation significantly reduced tumor size compared with radiation treatment followed by IFN-beta. The combination of IFN-beta and ionizing radiation showed synergy against ARMS by sensitizing tumor cells to the cytotoxic effects of ionizing radiation and by altering tumor vasculature, thereby improving oxygenation. Therefore, IFN-beta and ionizing radiation may be an effective combination for treatment of ARMS. Mol Cancer Ther; 9(3); 761-71.

PMID: 20197402 [PubMed - as supplied by publisher]

Intravital imaging of amyloid plaques in a transgenic mouse model using optical-resolution photoacoustic microscopy.

Opt Lett. 2009 Dec 15;34(24):3899-901

Authors: Hu S, Yan P, Maslov K, Lee JM, Wang LV

We report optical-resolution photoacoustic microscopy (OR-PAM) for in vivo imaging of amyloid plaques in an Alzheimer's disease mouse model. Validation using conventional fluorescence microscopy and multiphoton microscopy shows that OR-PAM has sufficient sensitivity and spatial resolution to identify amyloid plaques in living brains. In addition, with dual-wavelength OR-PAM, the three-dimensional morphology of amyloid plaques and the surrounding microvasculature are imaged simultaneously through a cranial window without angiographic contrast agents. OR-PAM, capable of providing both exogenous molecular contrast and endogenous hemoglobin contrast, has the potential to serve as a new technology for in vivo microscopic observations of cerebral plaque deposits.

PMID: 20016651 [PubMed - indexed for MEDLINE]

Ultrasound-Microbubble-Mediated Intercellular Adhesion Molecule-1 Small Interfering Ribonucleic Acid Transfection Attenuates Neointimal Formation After Arterial Injury in Mice.

J Am Coll Cardiol. 2010 Mar 2;55(9):904-913

Authors: Suzuki JI, Ogawa M, Takayama K, Taniyama Y, Morishita R, Hirata Y, Nagai R, Isobe M

OBJECTIVES: The purpose of this study was to investigate the efficiency of small interfering ribonucleic acid (siRNA) in murine arteries. We transfected it using a nonviral ultrasound-microbubble-mediated in vivo gene delivery system. BACKGROUND: siRNA is an effective methodology to suppress gene function. The siRNA can be synthesized easily; however, a major obstacle in the use of siRNA as therapeutics is the difficulty involved in effective in vivo delivery. METHODS: To investigate the efficiency of nonviral ultrasound-microbubble-mediated in vivo siRNA delivery, we used a fluorescein-labeled siRNA, green fluorescent protein (GFP) siRNA, and intercellular adhesion molecule (ICAM)-1 siRNA in murine arteries. Murine femoral arteries were injured using flexible wires to establish arterial injury. RESULTS: The fluorescein-labeled siRNA and GFP siRNA showed that this nonviral approach could deliver siRNA into target arteries effectively without any tissue damage and systemic adverse effects. ICAM-1 siRNA transfection into murine injured arteries significantly suppressed the development of neointimal formation in comparison to those in the control group. Immunohistochemistry revealed that accumulation of T cells and adhesion molecule positive cells was observed in nontreated injured arteries, whereas siRNA suppressed accumulation. CONCLUSIONS: The nonviral ultrasound-microbubble delivery of siRNA ensures effective transfection into target arteries. ICAM-1 siRNA has the potential to suppress arterial neointimal formation. Transfection of siRNA can be beneficial for the clinical treatment of cardiovascular and other inflammatory diseases.

PMID: 20185042 [PubMed - as supplied by publisher]

Uterine NK Cells, Spiral Artery Modification and the Regulation of Blood Pressure During Mouse Pregnancy.

Am J Reprod Immunol. 2010 Feb 17;

Authors: Burke SD, Barrette VF, Gravel J, Carter AL, Hatta K, Zhang J, Chen Z, Leno-Durán E, Bianco J, Leonard S, Murrant C, Adams MA, Anne Croy B

Citation Burke SD, Barrette VF, Gravel J, Carter ALI, Hatta K, Zhang J, Chen Z, Leno-Durán E, Bianco J, Leonard S, Murrant C, Adams MA, Anne Croy B. Uterine NK cells, spiral artery modification and the regulation of blood pressure during mouse pregnancy. Am J Reprod Immunol 2010 Reproductive success in mammals involves coordinated changes in the immune and cardiovascular as well as in the neuroendocrine and reproductive systems. This review addresses studies that identify potential links for NK cells and T cells with the local and systemic cardiovascular adaptations of pregnancy. The studies reviewed have utilized immunohistochemisty and in vivo analyses of vascular parameters by ultrasound, chronic monitoring of hemodynamics via radiotelemetric recording and intravital microscopy. At the uterine level, functional subsets of uterine natural killer cells were identified. These included subsets expressing molecules important for vasoregulation, in addition to those previously identified for angiogenesis. Spiral arteries showed conducted responses that could account for conceptus control of vasoactivity and mouse gestational blood pressure 5-phase pattern. Vascular immunology is an emerging transdisciplinary field, critical for both reproductive immunology and cardiovascular disease.

PMID: 20175772 [PubMed - as supplied by publisher]

Dendritic Cells Loaded with Ultrasound-Ablated Tumour Induce in vivo Specific Antitumour Immune Responses.

Ultrasound Med Biol. 2010 Mar;36(3):441-448

Authors: Deng J, Zhang Y, Feng J, Wu F

Previous studies have shown that high-intensity focused ultrasound (HIFU) ablation can induce a local inflammation with marked infiltration of dendritic cells (DCs). The purpose of this study was to investigate whether DCs could capture and present activating signals delivered by necrotic tumour cells that remain in situ after HIFU, thus initiating specific antitumour immunity. Tumour debris was derived from a mouse H22 tumour model after HIFU ablation. Bone marrow-derived DCs were loaded with HIFU-treated tumour, tumour lysate and mouse serum. Syngeneic naïve C57BL/6J mice were immunised with three loaded DCs followed by a subsequent H22 tumour challenge. Tumour size and survival were then recorded in each vaccinated mouse. The results showed that both HIFU-ablated tumour and tumour lysate could significantly increase the number of mature DCs and the secretion of IL-12 and IFN-gamma (p<0.001). The proliferation of splenic lymphocytes co-incubated with the loaded-DCs was significantly higher in both HIFU-ablated tumour and tumour lysate groups (p<0.01). Cytotoxocity and TNF-alpha and IFN-gamma secretion of cytotoxic T lymphocytes against H22 cells were significantly higher in HIFU-ablated tumour group than that in tumour lysate group (p<0.01). After the H22 tumour challenge, a significant decrease of tumour volume was observed in HIFU-ablated tumour group (p<0.01). However, there was no statistical difference of long-term survival rates among three groups (p>0.05). It is concluded that DCs can be activated by HIFU-ablated tumour debris and, thus, initiate host specific antitumour immune response after HIFU therapy. (E-mail: mfengwu@yahoo.com).

PMID: 20172447 [PubMed - as supplied by publisher]

Ultrasound-enhanced drug dispersion through solid tumours and its possible role in aiding ultrasound-targeted cancer chemotherapy.

Cancer Lett. 2010 Feb 1;288(1):94-8

Authors: Nomikou N, Li YS, McHale AP

It has been demonstrated that inadequate dispersion of cancer chemotherapeutic drugs throughout the tissues of larger, relatively poorly vascularised tumours compromises the therapeutic effectiveness of such drugs. Recently we demonstrated that electric fields could be exploited to achieve dispersion of a cancer chemotherapeutic drug through relatively impermeable tissues of a poorly vascularised solid tumour model. Using a modified Sonidel SP100 sonoporator we demonstrate that ultrasound may enhance the toxicity of a cancer chemotherapeutic drug by dispersing the drug through relatively impermeable tissues of a non-vascularised tumour model in vivo. We suggest that such a phenomenon may play a significant role in ultrasound targeting of cancer chemotherapeutic drugs, particularly in the treatment of solid tumours.

PMID: 19674834 [PubMed - indexed for MEDLINE]

Endogenous generation and protective effects of nitro-fatty acids in a murine model of focal cardiac ischaemia and reperfusion.

Cardiovasc Res. 2010 Jan 1;85(1):155-66

Authors: Rudolph V, Rudolph TK, Schopfer FJ, Bonacci G, Woodcock SR, Cole MP, Baker PR, Ramani R, Freeman BA

AIMS: Nitrated fatty acids (NO(2)-FA) have been identified as endogenous anti-inflammatory signalling mediators generated by oxidative inflammatory reactions. Herein the in vivo generation of nitro-oleic acid (OA-NO(2)) and nitro-linoleic acid (LNO(2)) was measured in a murine model of myocardial ischaemia and reperfusion (I/R) and the effect of exogenous administration of OA-NO(2) on I/R injury was evaluated. METHODS AND RESULTS: In C57/BL6 mice subjected to 30 min of coronary artery ligation, endogenous OA-NO(2) and LNO(2) formation was observed after 30 min of reperfusion, whereas no NO(2)-FA were detected in sham-operated mice and mice with myocardial infarction without reperfusion. Exogenous administration of 20 nmol/g body weight OA-NO(2) during the ischaemic episode induced profound protection against I/R injury with a 46% reduction in infarct size (normalized to area at risk) and a marked preservation of left ventricular function as assessed by transthoracic echocardiography, compared with vehicle-treated mice. Administration of OA-NO(2) inhibited activation of the p65 subunit of nuclear factor kappaB (NFkappaB) in I/R tissue. Experiments using the NFkappaB inhibitor pyrrolidinedithiocarbamate also support that protection lent by OA-NO(2) was in part mediated by inhibition of NFkappaB. OA-NO(2) inhibition of NFkappaB activation was accompanied by suppression of downstream intercellular adhesion molecule 1 and monocyte chemotactic protein 1 expression, neutrophil infiltration, and myocyte apoptosis. CONCLUSION: This study reveals the de novo generation of fatty acid nitration products in vivo and reveals the anti-inflammatory and potential therapeutic actions of OA-NO(2) in myocardial I/R injury.

PMID: 19666678 [PubMed - indexed for MEDLINE]

Type 1 diabetic cardiomyopathy in the Akita (Ins2WT/C96Y) mouse model is characterized by lipotoxicity and diastolic dysfunction with preserved systolic function.

Am J Physiol Heart Circ Physiol. 2009 Dec;297(6):H2096-108

Authors: Basu R, Oudit GY, Wang X, Zhang L, Ussher JR, Lopaschuk GD, Kassiri Z

Diabetic cardiomyopathy is an important contributor to diastolic and systolic heart failure. We examined the nature and mechanism of the cardiomyopathy in Akita (Ins2(WT/C96Y)) mice, a model of genetic nonobese type 1 diabetes that recapitulates human type 1 diabetes. Cardiac function was evaluated in male Ins2WT/C96Y and their littermate control (Ins2WT/WT) mice using echocardiography and tissue Doppler imaging, in vivo hemodynamic measurements, as well as ex vivo working heart preparation. At 3 and 6 mo of age, Ins2WT/C96Y mice exhibited preserved cardiac systolic function compared with Ins2WT/WT mice, as evaluated by ejection fraction, fractional shortening, left ventricular (LV) end-systolic pressure and maximum rate of increase in LV pressure in vivo, cardiac work, cardiac power, and rate-pressure product ex vivo. Despite the unaltered systolic function, Ins2WT/C96Y mice exhibited significant and progressive diastolic dysfunction at 3 and 6 mo of age compared with Ins2WT/WT mice as assessed by tissue and pulse Doppler imaging (E-wave velocity, isovolumetric relaxation time) and by in vivo hemodynamic measurements (LV end-diastolic pressure, time constant of LV relaxation, and maximum rate of decrease in LV pressure). We found no evidence of myocardial hypertrophy or fibrosis in the Ins2WT/C96Y myocardium. Consistent with the lack of fibrosis, expression of procollagen-alpha type I, procollagen-alpha type III, and fibronectin were not increased in these hearts. Ins2WT/C96Y hearts showed significantly reduced sarcoplasmic reticulum Ca2+-ATPase 2a (cardiac sarcoplasmic reticulum Ca2+ pump) levels, elevated beta-myosin heavy chain isoform, increased long-chain fatty acids, and triacylglycerol with evidence of lipotoxicity, as indicated by a significant rise in ceramide, diacylglycerol, and lipid deposits in the myocardium. Consistent with metabolic perturbation, and a switch to fatty acid oxidation from glucose oxidation in Ins2WT/C96Y hearts, expression of mitochondrial long-chain acyl-CoA dehydrogenase and pyruvate dehydrogenase kinase isoform 4 were increased. Insulin treatment reversed the diastolic dysfunction, the elevated B-type natriuretic peptide and beta-myosin heavy chain, and the reduced sarcoplasmic reticulum Ca2+-ATPase 2a levels with abolition of cardiac lipotoxicity. We conclude that early type 1 diabetic cardiomyopathy is characterized by diastolic dysfunction associated with lipotoxic cardiomyopathy with preserved systolic function in the absence of interstitial fibrosis and hypertrophy.

PMID: 19801494 [PubMed - indexed for MEDLINE]

Targeted Contrast-Enhanced Ultrasound Imaging of Tumor Angiogenesis with Contrast Microbubbles Conjugated to Integrin-Binding Knottin Peptides.

J Nucl Med. 2010 Feb 11;

Authors: Willmann JK, Kimura RH, Deshpande N, Lutz AM, Cochran JR, Gambhir SS

Targeted contrast-enhanced ultrasound imaging is increasingly being recognized as a powerful imaging tool for the detection and quantification of tumor angiogenesis at the molecular level. The purpose of this study was to develop and test a new class of targeting ligands for targeted contrast-enhanced ultrasound imaging of tumor angiogenesis with small, conformationally constrained peptides that can be coupled to the surface of ultrasound contrast agents. METHODS: Directed evolution was used to engineer a small, disulfide-constrained cystine knot (knottin) peptide that bound to alphavbeta3 integrins with a low nanomolar affinity (KnottinIntegrin). A targeted contrast-enhanced ultrasound imaging contrast agent was created by attaching KnottinIntegrin to the shell of perfluorocarbon-filled microbubbles (MB-KnottinIntegrin). A knottin peptide with a scrambled sequence was used to create control microbubbles (MB-KnottinScrambled). The binding of MB-KnottinIntegrin and MB-KnottinScrambled to alphavbeta3 integrin-positive cells and control cells was assessed in cell culture binding experiments and compared with that of microbubbles coupled to an anti-alphavbeta3 integrin monoclonal antibody (MBalphavbeta3) and microbubbles coupled to the peptidomimetic agent c(RGDfK) (MBcRGD). The in vivo imaging signals of contrast-enhanced ultrasound with the different types of microbubbles were quantified in 42 mice bearing human ovarian adenocarcinoma xenograft tumors by use of a high-resolution 40-MHz ultrasound system. RESULTS: MB-KnottinIntegrin attached significantly more to alphavbeta3 integrin-positive cells (1.76 +/- 0.49 [mean +/- SD] microbubbles per cell) than to control cells (0.07 +/- 0.006). Control MB-KnottinScrambled adhered less to alphavbeta3 integrin-positive cells (0.15 +/- 0.12) than MB-KnottinIntegrin. After blocking of integrins, the attachment of MB-KnottinIntegrin to alphavbeta3 integrin-positive cells decreased significantly. The in vivo ultrasound imaging signal was significantly higher after the administration of MB-KnottinIntegrin than after the administration of MBalphavbeta3 or control MB-KnottinScrambled. After in vivo blocking of integrin receptors, the imaging signal after the administration of MB-KnottinIntegrin decreased significantly (by 64%). The imaging signals after the administration of MB-KnottinIntegrin were not significantly different in the groups of tumor-bearing mice imaged with MB-KnottinIntegrin and with MBcRGD. Ex vivo immunofluorescence confirmed integrin expression on endothelial cells of human ovarian adenocarcinoma xenograft tumors. CONCLUSION: Integrin-binding knottin peptides can be conjugated to the surface of microbubbles and used for in vivo targeted contrast-enhanced ultrasound imaging of tumor angiogenesis. Our results demonstrate that microbubbles conjugated to small peptide-targeting ligands provide imaging signals higher than those provided by a large antibody molecule.

PMID: 20150258 [PubMed - as supplied by publisher]

In vivo characterization of the aortic wall stress-strain relationship.

Ultrasonics. 2010 Jan 14;

Authors: Danpinid A, Luo J, Vappou J, Terdtoon P, Konofagou EE

Arterial stiffness has been shown to be a good indicator of arterial wall disease. However, a single parameter is insufficient to describe the complex stress-strain relationship of a multi-component, non-linear tissue such as the aorta. We therefore propose a new approach to measure the stress-strain relationship locally in vivo noninvasively, and present a clinically relevant parameter describing the mechanical interaction between aortic wall constituents. The slope change of the circumferential stress-strain curve was hypothesized to be related to the contribution of elastin and collagen, and was defined as the transition strain (epsilon(theta)(T)). A two-parallel spring model was employed and three Young's moduli were accordingly evaluated, i.e., corresponding to the: elastic lamellae (E(1)), elastin-collagen fibers (E(2)) and collagen fibers (E(3)). Our study was performed on normal and Angiotensin II (AngII)-treated mouse abdominal aortas using the aortic pressure after catheterization and the local aortic wall diameters change from a cross-correlation technique on the radio frequency (RF) ultrasound signal at 30MHz and frame rate of 8kHz. Using our technique, the transition strain and three Young's moduli in both normal and pathological aortas were mapped in 2D. The slope change of the circumferential stress-strain curve was first observed in vivo under physiologic conditions. The transition strain was found at a lower strain level in the AngII-treated case, i.e., 0.029+/-0.006 for the normal and 0.012+/-0.004 for the AngII-treated aortas. E(1), E(2) and E(3) were equal to 69.7+/-18.6, 214.5+/-65.8 and 144.8+/-55.2kPa for the normal aortas, and 222.1+/-114.8, 775.0+/-586.4 and 552.9+/-519.1kPa for the AngII-treated aortas, respectively. This is because of the alteration of structures and content of the wall constituents, the degradation of elastic lamella and collagen formation due to AngII treatment. While such values illustrate the alteration of structure and content of the wall constituents related to AngII treatment, limitations regarding physical assumptions (isotropic, linear elastic) should be kept in mind. The transition strain, however, was shown to be a pressure independent parameter that can be clinically relevant and noninvasively measured using ultrasound-based motion estimation techniques. In conclusion, our novel methodology can assess the stress-strain relationship of the aortic wall locally in vivo and quantify important parameters for the detection and characterization of vascular disease.

PMID: 20138640 [PubMed - as supplied by publisher]

Timing of bone marrow cell delivery has minimal effects on cell viability and cardiac recovery after myocardial infarction.

Circ Cardiovasc Imaging. 2010 Jan;3(1):77-85

Authors: Swijnenburg RJ, Govaert JA, van der Bogt KE, Pearl JI, Huang M, Stein W, Hoyt G, Vogel H, Contag CH, Robbins RC, Wu JC

BACKGROUND: Despite ongoing clinical trials, the optimal time for delivery of bone marrow mononuclear cells (BMCs) after myocardial infarction is unclear. We compared the viability and effects of transplanted BMCs on cardiac function in the acute and subacute inflammatory phases of myocardial infarction. METHODS AND RESULTS: The time course of acute inflammatory cell infiltration was quantified by FACS analysis of enzymatically digested hearts of FVB mice (n=12) after left anterior descending artery ligation. Mac-1(+)Gr-1(high) neutrophil infiltration peaked at day 4. BMCs were harvested from transgenic FVB mice expressing firefly luciferase (Fluc) and green fluorescent protein (GFP). Afterward, 2.5x10(6) BMCs were injected into the left ventricle of wild-type FVB mice either immediately (acute BMC) or 7 days (subacute BMC) after myocardial infarction, or after a sham procedure (n=8 per group). In vivo bioluminescence imaging showed an early signal increase in both BMC groups at day 7, followed by a nonsignificant trend (P=0.203) toward improved BMC survival in the subacute BMC group that persisted until the bioluminescence imaging signal reached BACKGROUND: <0.01) and 6 weeks (both BMC groups versus saline; P<0.05) but no significant differences between the 2 BMC groups. FACS analysis of BMC-injected hearts at day 7 revealed that GFP(+) BMCs expressed hematopoietic (CD45, Mac-1, Gr-1), minimal progenitor (Sca-1, c-kit), and no endothelial (CD133, Flk-1) or cardiac (Trop-T) cell markers. CONCLUSIONS: Timing of BMC delivery has minimal effects on intramyocardial retention and preservation of cardiac function. In general, there is poor long-term engraftment and BMCs tend to adopt inflammatory cell phenotypes.

PMID: 19920031 [PubMed - indexed for MEDLINE]

Simultaneous multimodal imaging with integrated photoacoustic microscopy and optical coherence tomography.

Opt Lett. 2009 Oct 1;34(19):2961-3

Authors: Jiao S, Xie Z, Zhang HF, Puliafito CA

We have developed a multimodal imaging technique by integrating photoacoustic microscopy and spectral-domain optical coherence tomography to provide simultaneous volumetric microscopic imaging of both optical absorption and scattering contrasts in biological tissues. In the integrated system, the two imaging modalities share the same optical scanning and delivery mechanisms after their probing and illumination light beams are combined. By further synchronizing the image acquisitions, the images from the two modalities are intrinsically registered. The capabilities of this novel technique were demonstrated by imaging both the microanatomy and microvasculature in mouse ears in vivo.

PMID: 19794782 [PubMed - indexed for MEDLINE]

Mesenchymal stem cells promote matrix metalloproteinase secretion by cardiac fibroblasts and reduce cardiac ventricular fibrosis after myocardial infarction.

Stem Cells. 2009 Nov;27(11):2734-43

Authors: Mias C, Lairez O, Trouche E, Roncalli J, Calise D, Seguelas MH, Ordener C, Piercecchi-Marti MD, Auge N, Salvayre AN, Bourin P, Parini A, Cussac D

Recent studies showed that mesenchymal stem cells (MSCs) transplantation significantly decreased cardiac fibrosis; however, the mechanisms involved in these effects are still poorly understood. In this work, we investigated whether the antifibrotic properties of MSCs involve the regulation of matrix metalloproteinases (MMPs) and matrix metalloproteinase endogenous inhibitor (TIMP) production by cardiac fibroblasts. In vitro experiments showed that conditioned medium from MSCs decreased viability, alpha-smooth muscle actin expression, and collagen secretion of cardiac fibroblasts. These effects were concomitant with the stimulation of MMP-2/MMP-9 activities and membrane type 1 MMP expression. Experiments performed with fibroblasts from MMP2-knockout mice demonstrated that MMP-2 plays a preponderant role in preventing collagen accumulation upon incubation with conditioned medium from MSCs. We found that MSC-conditioned medium also decreased the expression of TIMP2 in cardiac fibroblasts. In vivo studies showed that intracardiac injection of MSCs in a rat model of postischemic heart failure induced a significant decrease in ventricular fibrosis. This effect was associated with the improvement of morphological and functional cardiac parameters. In conclusion, we showed that MSCs modulate the phenotype of cardiac fibroblasts and their ability to degrade extracellular matrix. These properties of MSCs open new perspectives for understanding the mechanisms of action of MSCs and anticipate their potential therapeutic or side effects.

PMID: 19591227 [PubMed - indexed for MEDLINE]

Ultrasonic disruption of the blood-brain barrier enables in vivo functional mapping of the mouse barrel field cortex with manganese-enhanced MRI.

Neuroimage. 2010 Jan 20;

Authors: Howles GP, Qi Y, Johnson GA

Though mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains technically challenging. One approach-Activation-Induced Manganese-enhanced MRI (AIM MRI)-has been used successfully to map neuronal activity in rodents. In AIM MRI, manganese(2+)acts a calcium analog and accumulates in depolarized neurons. Because manganese(2+)shortens T1, regions of elevated neuronal activity enhance in MRI. However, because manganese does not cross the blood-brain barrier (BBB), the need to osmotically disrupt the BBB has limited the use of AIM MRI, particularly in mice. In this work, the BBB was opened in mice using unfocused, transcranial ultrasound in combination with gas-filled microbubbles. Using this non-invasive technique to open the BBB bilaterally, manganese could be quickly administered to the whole mouse brain. With this approach, AIM MRI was used to map the neuronal response to unilateral mechanical stimulation of the vibrissae in lightly sedated mice. The resultant 3D activation map agreed well with published representations of the vibrissae regions of the barrel field cortex. The anterior portions of the barrel field cortex corresponding to the more rostral vibrissae showed greater activation, consistent with previous literature. Because the ultrasonic opening of the BBB is simple, fast, and non-invasive, this approach is suitable for high-throughput and longitudinal studies in awake mice. This approach enables a new way to map neuronal activity in mice with manganese.

PMID: 20096789 [PubMed - as supplied by publisher]

Evans blue dye-enhanced capillary-resolution photoacoustic microscopy in vivo.

J Biomed Opt. 2009 Sep-Oct;14(5):054049

Authors: Yao J, Maslov K, Hu S, Wang LV

Complete and continuous imaging of microvascular networks is crucial for a wide variety of biomedical applications. Photoacoustic tomography can provide high resolution microvascular imaging using hemoglobin within red blood cells (RBCs) as an endogenic contrast agent. However, intermittent RBC flow in capillaries results in discontinuous and fragmentary capillary images. To overcome this problem, we use Evans blue (EB) dye as a contrast agent for in vivo photoacoustic imaging. EB has strong optical absorption and distributes uniformly in the blood stream by chemically binding to albumin. With the help of EB, complete and continuous microvascular networks--especially capillaries--are imaged. The diffusion dynamics of EB leaving the blood stream and the clearance dynamics of the EB-albumin complex are also quantitatively investigated.

PMID: 19895150 [PubMed - indexed for MEDLINE]

Photoacoustic tomography of small animal brain with a curved array transducer.

J Biomed Opt. 2009 Sep-Oct;14(5):054007

Authors: Yang X, Maurudis A, Gamelin J, Aguirre A, Zhu Q, Wang LV

We present the application of a curved array photoacoustic tomographic imaging system that can provide rapid, high-resolution photoacoustic imaging of small animal brains. The system is optimized to produce a B-mode, 90-deg field-of-view image at sub-200-microm resolution at a frame rate of approximately 1 frame/second when a 10-Hz pulse repetition rate laser is employed. By rotating samples, a complete 360-deg scan can be achieved within 15 s. In previous work, two-dimensional (2-D) ex vivo mouse brain cortex imaging has been reported. We report three-dimensional (3-D) small animal brain imaging obtained with the curved array system. The results are presented as a series of 2-D cross-sectional images. Besides structural imaging, the blood oxygen saturation of the animal brain cortex is also measured in vivo. In addition, the system can measure the time-resolved relative changes in blood oxygen saturation level in the small animal brain cortex. Last, ultrasonic gel coupling, instead of the previously adopted water coupling, is conveniently used in near-real-time 2-D imaging.

PMID: 19895109 [PubMed - indexed for MEDLINE]

Spatial and temporal-controlled tissue heating on a modified clinical ultrasound scanner for generating mild hyperthermia in tumors.

IEEE Trans Biomed Eng. 2010 Jan;57(1):155-66

Authors: Kruse DE, Lai CY, Stephens DN, Sutcliffe P, Paoli EE, Barnes SH, Ferrara KW

A new system is presented for generating controlled tissue heating with a clinical ultrasound scanner, and initial in vitro and in vivo results are presented that demonstrate both transient and sustained heating in the mild-hyperthermia range of 37 ( degrees )C-42 ( degrees )C. The system consists of a Siemens Antares ultrasound scanner, a custom dual-frequency three-row transducer array and an external temperature feedback control system. The transducer has two outer rows that operate at 1.5 MHz for tissue heating and a center row that operates at 5 MHz for B-mode imaging to guide the therapy. We compare the field maps obtained using a hydrophone against calculations of the ultrasound beam based on monochromatic and linear assumptions. Using the finite-difference time-domain (FDTD) method, we compare predicted time-dependent thermal profiles to measured profiles for soy tofu as a tissue-mimicking phantom. In vitro results show differential heating of 6 ( degrees )C for chicken breast and tofu. In vivo tests of the system were performed on three mice bearing Met-1 tumors, which is a model of aggressive, metastatic, and highly vascular breast cancer. In superficially implanted tumors, we demonstrate controlled heating to 42 ( degrees )C. We show that the system is able to maintain the temperature to within 0.1 ( degrees )C of the desired temperature both in vitro and in vivo.

PMID: 20064754 [PubMed - in process]

Isoflurane postconditioning protects against reperfusion injury by preventing mitochondrial permeability transition by an endothelial nitric oxide synthase-dependent mechanism.

Anesthesiology. 2010 Jan;112(1):73-85

Authors: Ge ZD, Pravdic D, Bienengraeber M, Pratt PF, Auchampach JA, Gross GJ, Kersten JR, Warltier DC

BACKGROUND: The role of endothelial nitric oxide synthase (eNOS) in isoflurane postconditioning (IsoPC)-elicited cardioprotection is poorly understood. The authors addressed this issue using eNOS mice. METHODS: In vivo or Langendorff-perfused mouse hearts underwent 30 min of ischemia followed by 2 h of reperfusion in the presence and absence of postconditioning produced with isoflurane 5 min before and 3 min after reperfusion. Ca+-induced mitochondrial permeability transition (MPT) pore opening was assessed in isolated mitochondria. Echocardiography was used to evaluate ventricular function. RESULTS: Postconditioning with 0.5, 1.0, and 1.5 minimum alveolar concentrations of isoflurane decreased infarct size from 56 +/- 10% (n = 10) in control to 48 +/- 10%, 41 +/- 8% (n = 8, P < 0.05), and 38 +/- 10% (n = 8, P < 0.05), respectively, and improved cardiac function in wild-type mice. Improvement in cardiac function by IsoPC was blocked by N-nitro-L-arginine methyl ester (a nonselective nitric oxide synthase inhibitor) administered either before ischemia or at the onset of reperfusion. Mitochondria isolated from postconditioned hearts required significantly higher in vitro Ca+ loading than did controls (78 +/- 29 microm vs. 40 +/- 25 microm CaCl2 per milligram of protein, n = 10, P < 0.05) to open the MPT pore. Hearts from eNOS mice displayed no marked differences in infarct size, cardiac function, and sensitivity of MPT pore to Ca+, compared with wild-type hearts. However, IsoPC failed to alter infarct size, cardiac function, or the amount of Ca+ necessary to open the MPT pore in mitochondria isolated from the eNOS hearts compared with control hearts. CONCLUSIONS: IsoPC protects mouse hearts from reperfusion injury by preventing MPT pore opening in an eNOS-dependent manner. Nitric oxide functions as both a trigger and a mediator of cardioprotection produced by IsoPC.

PMID: 19996950 [PubMed - indexed for MEDLINE]

High-Resolution Ultrasound Imaging. A Novel Technique for the Noninvasive in Vivo Analysis of Endometriotic Lesion and Cyst Formation in Small Animal Models.

Am J Pathol. 2009 Dec 30;

Authors: Laschke MW, Körbel C, Rudzitis-Auth J, Gashaw I, Reinhardt M, Hauff P, Zollner TM, Menger MD

Endometriosis, the presence of endometrial tissue at ectopic sites, is a highly prevalent gynecological disease severely affecting a patient's quality of life. To analyze the mechanisms involved in the disease and to identify new molecular targets for effective therapies, small animal models are an important approach. Herein, we report the first use of high-resolution ultrasound imaging for the in vivo analysis of intraperitoneal endometriotic lesions in mice. This noninvasive technology allows for the repetitive quantitative analysis of growth, cyst development, and adhesion formation of endometriotic lesions with a low intra- and interobserver variability. Moreover, it enables one to easily differentiate between endometrial cysts and stroma. Accordingly, volume measurements of both endometrial cysts and stroma indicated that the initial establishment of endometriotic lesions is associated with enhanced cellular proliferation, followed by a phase of increased secretory activity of endometrial glands. Results of ultrasound analysis correlated well with measurements of lesion volumes by caliper and histology. Importantly, ultrasound imaging could be performed repetitively and noninvasively and reflected best the in vivo situation. The technique could further be demonstrated to successfully monitor the significant inhibition of growth of endometriotic lesions after specific estrogen receptor destabilizator treatment. Thus, high-resolution ultrasound imaging represents an important tool for future preclinical small animal studies, which address the pathophysiology of endometriosis and the development of new treatment strategies.

PMID: 20042678 [PubMed - as supplied by publisher]