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Sustained angiogenesis is essential for the development of solid tumors and metastatic disease. Disruption of signaling pathways that govern tumor vascularity provide a potential avenue to thwart cancer progression. Through phage display-based functional proteomics, immunohistochemical analysis of human pancreatic ductal carcinoma (PDAC) specimens, and in vitro validation, we reveal that hornerin, an S100 fused-type protein, is highly expressed on pancreatic tumor endothelium in a vascular endothelial growth factor (VEGF)-independent manner. Murine-specific hornerin knockdown in PDAC xenografts results in tumor vessels with decreased radii and tortuosity. Hornerin knockdown tumors have significantly reduced leakiness, increased oxygenation, and greater apoptosis. Additionally, these tumors show a significant reduction in growth, a response that is further heightened when therapeutic inhibition of VEGF receptor 2 (VEGFR2) is utilized in combination with hornerin knockdown. These results indicate that hornerin is highly expressed in pancreatic tumor endothelium and alters tumor vessel parameters through a VEGF-independent mechanism., Angiogenesis is essential for solid tumor progression. Here, the authors interrogate the proteome of pancreatic cancer endothelium via phage display and identify hornerin as a critical protein whose expression is essential to maintain the pancreatic cancer vasculature through a VEGF-independent mechanism.

Amyotrophic lateral sclerosis (ALS) is a generally fatal neurodegenerative disease of adults that produces weakness and atrophy due to dysfunction and death of upper and lower motor neurons. We used RNA-sequencing (RNA-seq) to analyze expression of all mitochondrial DNA (mtDNA)-encoded respiratory genes in ALS and CTL human cervical spinal cords (hCSC) and isolated motor neurons. We analyzed with RNA-seq mtDNA gene expression in human neural stem cells (hNSC) exposed to recombinant human mitochondrial transcription factor A (rhTFAM), visualized in 3-dimensions clustered gene networks activated by rhTFAM, quantitated their interactions with other genes and determined their gene ontology (GO) families. RNA-seq and quantitative PCR (qPCR) analyses showed reduced mitochondrial gene expression in ALS hCSC and ALS motor neurons isolated by laser capture microdissection (LCM), and revealed that hNSC and CTL human cervical spinal cords were similar. Rats treated with i.v. rhTFAM showed a dose-response increase in brain respiration and an increase in spinal cord mitochondrial gene expression. Treatment of hNSC with rhTFAM increased expression of mtDNA-encoded respiratory genes and produced one major and several minor clusters of gene interactions. Gene ontology (GO) analysis of rhTFAM-stimulated gene clusters revealed enrichment in GO families involved in RNA and mRNA metabolism, suggesting mitochondrial-nuclear signaling. In postmortem ALS hCSC and LCM-isolated motor neurons we found reduced expression of mtDNA respiratory genes. In hNSC's rhTFAM increased mtDNA gene expression and stimulated mRNA metabolism by unclear mechanisms. rhTFAM may be useful in improving bioenergetic function in ALS.

ObjectivesThe goal of this study was to assess the relationship among extracellular volume (ECV), native T1, and systolic strain in hypertensive patients with left ventricular hypertrophy (HTN LVH), hypertensive patients without LVH (HTN non-LVH), and normotensive controls.BackgroundDiffuse myocardial fibrosis in HTN LVH patients, as reflected by increased ECV and native T1, may be an underlying mechanism contributing to increased cardiovascular risk compared with HTN non-LVH subjects and controls. Furthermore, increased diffuse fibrosis in HTN LVH subjects may be associated with reduced peak systolic and early diastolic strain rate compared with the other 2 groups.MethodsT1 mapping was performed in 20 HTN LVH (mean age, 55 ± 11 years), 23 HTN non-LVH (mean age, 61 ± 12 years), and 22 control subjects (mean age, 54 ± 7 years) on a Siemens 1.5-T Avanto (Siemens Healthcare, Erlangen, Germany) using a previously validated modified look-locker inversion-recovery pulse sequence. T1 was measured pre-contrast and 10, 15, and 20 min after injection of 0.15 mmol/kg gadopentetate dimeglumine, and the mean ECV and native T1 were determined for each subject. Measurement of circumferential strain parameters were performed using cine displacement encoding with stimulated echoes.ResultsHTN LVH subjects had higher native T1 compared with controls (p < 0.05). HTN LVH subjects had higher ECV compared with HTN non-LVH subjects and controls (p < 0.05). Peak systolic circumferential strain and early diastolic strain rates were reduced in HTN LVH subjects compared with HTN non-LVH subjects and controls (p

Purpose Gene-modified mice may be used to elucidate molecular mechanisms underlying abnormal myocardial blow flow (MBF). We sought to develop a quantitative myocardial perfusion imaging technique for mice and to test the hypothesis that myocardial perfusion reserve (MPR) is reduced in a mouse model of diet-induced obesity (DIO). Methods A dual-contrast saturation-recovery sequence with ky-t undersampling and a motion-compensated compressed sensing reconstruction algorithm was developed for first-pass MRI on a small-bore 7 Tesla system. Control mice were imaged at rest and with the vasodilators ATL313 and Regadenoson (n = 6 each). In addition, we imaged mice fed a high-fat diet (HFD) for 24 weeks. Results In control mice, MBF was 5.7 ± 0.8 mL/g/min at rest and it increased to 11.8 ± 0.6 mL/g/min with ATL313 and to 10.4 ± 0.3 mL/g/min with Regadenoson. In HFD mice, we detected normal resting MBF (5.6 ± 0.4 versus 5.0 ± 0.3 on control diet), low MBF at stress (7.7 ± 0.4 versus 10.4 ± 0.3 on control diet, P

Currently, there is no ideal noninvasive method to quantify the progressive loss of pancreatic β-cell mass (BCM) that occurs in type 1 diabetes. Magnetic resonance imaging has detected gross differences in BCM between healthy and diabetic mice using the contrast agent manganese, which labels functional β-cells and increases the water proton relaxation rate (R1), but its ability to measure gradations in BCM during disease progression is unknown. Our objective was to test the hypothesis that measurements of the manganese-enhanced pancreatic R1 could detect decreasing BCM in a mouse model of type 1 diabetes. We used cyclophosphamide-accelerated BDC2.5 T-cell receptor transgenic nonobese diabetic mice, which experience development of type 1 diabetes during a 7-day time period after cyclophosphamide injection, whereas transgene-negative mice do not. We measured the manganese-enhanced pancreatic R1 before cyclophosphamide injection (day 0) and on days 3, 4, 5, and 7 afterward. Pancreatic R1 remained constant in transgene-negative mice and decreased stepwise day-to-day in transgene-positive mice, mirroring their loss of BCM, confirmed by pancreatic insulin measurements and histology. Changes in R1 in transgene-positive mice occurred before elevations in blood glucose, a clinical indicator of diabetes, suggesting potential for early noninvasive detection of changes in functional BCM.

Purpose To develop and validate modified Look-Locker (MOLLI) protocols to generate myocardial T1 maps within clinically acceptable breath-hold durations and to compare partition coefficients (\g=l\) of gadolinium (Gd)-DTPA determined from either bolus injection (BI) or continuous infusion (CI) techniques.

Objectives The purpose of this paper was to compare quantitative cardiac magnetic resonance (CMR) first-pass contrast-enhanced perfusion imaging to qualitative interpretation for determining the presence and severity of coronary artery disease (CAD). Background Adenosine CMR can detect CAD by measuring perfusion reserve (PR) or by qualitative interpretation (QI). Methods Forty-one patients with an abnormal nuclear stress scheduled for X-ray angiography underwent dual-bolus adenosine CMR. Segmental myocardial perfusion analyzed using both QI and PR by Fermi function deconvolution was compared to quantitative coronary angiography. Results In the 30 patients with complete quantitative data, PR (mean ± SD) decreased stepwise as coronary artery stenosis (CAS) severity increased: 2.42 ± 0.94 for 70% (p 50% (83% vs. 80%), and CAS >70% (77% vs. 67%). Agreement between observers was higher for quantitative analysis than for qualitative analysis. Using PR, patients with triple-vessel CAD had a higher burden of detectable ischemia than patients with single-vessel CAD (60% vs. 25%; p = 0.02), whereas no difference was detected by QI (31% vs. 21%; p = 0.26). In segments with myocardial scar (n = 64), PR was 3.10 ± 1.34 for patients with CAS 50% (p Conclusions Quantitative PR by CMR differentiates moderate from severe stenoses in patients with known or suspected CAD. The PR analysis differentiates triple- from single-vessel CAD, whereas QI does not, and determines the severity of CAS subtending myocardial scar. This has important implications for assessment of prognosis and therapeutic decision making.

Background The purpose was to determine the reproducibility and utility of rest, exercise, and perfusion reserve (PR) measures by contrast-enhanced (CE) calf perfusion magnetic resonance imaging (MRI) of the calf in normal subjects (NL) and patients with peripheral arterial disease (PAD). Methods Eleven PAD patients with claudication (ankle-brachial index 0.67 ±0.14) and 16 age-matched NL underwent symptom-limited CE-MRI using a pedal ergometer. Tissue perfusion and arterial input were measured at rest and peak exercise after injection of 0.1 mM/kg of gadolinium-diethylnetriamine pentaacetic acid (Gd-DTPA). Tissue function (TF) and arterial input function (AIF) measurements were made from the slope of time-intensity curves in muscle and artery, respectively, and normalized to proton density signal to correct for coil inhomogeneity. Perfusion index (PI) = TF/AIF. Perfusion reserve (PR) = exercise TF/ rest TF. Intraclass correlation coefficient (ICC) was calculated from 11 NL and 10 PAD with repeated MRI on a different day. Results Resting TF was low in NL and PAD (mean ± SD 0.25 ± 0.18 vs 0.35 ± 0.71, p = 0.59) but reproducible (ICC 0.76). Exercise TF was higher in NL than PAD (5.5 ± 3.2 vs. 3.4 ± 1.6, p = 0.04). Perfusion reserve was similar between groups and highly variable (28.6 ± 19.8 vs. 42.6 ± 41.0, p = 0.26). Exercise TF and PI were reproducible measures (ICC 0.63 and 0.60, respectively). Conclusion Although rest measures are reproducible, they are quite low, do not distinguish NL from PAD, and lead to variability in perfusion reserve measures. Exercise TF and PI are the most reproducible MRI perfusion measures in PAD for use in clinical trials.

Purpose: To develop and validate a technique for near-automated definition of myocardial regions of interest suitable for perfusion evaluation during vasodilator stress cardiac magnetic resonance (MR) imaging. Materials and Methods: The institutional review board approved the study protocol, and all patients provided informed consent. Image noise density distribution was used as a basis for endocardial and epicardial border detection combined with non-rigid registration. This method was tested in 42 patients undergoing contrast material-enhanced cardiac MR imaging (at 1.5 T) at rest and during vasodilator (adenosine or regadenoson) stress, including 15 subjects with normal myocardial perfusion and 27 patients referred for coronary angiography. Contrast enhancement-time curves were near-automatically generated and were used to calculate perfusion indexes. The results were compared with results of conventional manual analysis, using quantitative coronary angiography results as a reference for stenosis greater than 50%. Statistical analyses included the Student t test, linear regression, Bland-Altman analysis, and kappa statistics. Results: Analysis of one sequence required less than 1 minute and resulted in high-quality contrast enhancement curves both at rest and stress (mean signal-to-noise ratios, 17 +/- 7 [standard deviation] and 22 +/- 8, respectively), showing expected patterns of first-pass perfusion. Perfusion indexes accurately depicted stress-induced hyperemia (increased upslope, from 6.7 sec(-1) +/- 2.3 to 15.6 sec(-1) +/- 5.9; P < .0001). Measured segmental pixel intensities correlated highly with results of manual analysis (r = 0.95). The derived perfusion indexes also correlated highly with (r up to 0.94) and showed the same diagnostic accuracy as manual analysis (area under the receiver operating characteristic curve, up to 0.72 vs 0.73). Conclusion: Despite the dynamic nature of contrast-enhanced image sequences and respiratory motion, fast near-automated detection of myocardial segments and accurate quantification of tissue contrast is feasible at rest and during vasodilator stress. This technique, shown to be as accurate as conventional manual analysis, allows detection of stress-induced perfusion abnormalities.

Methods Sixteen healthy subjects and 3 symptomatic PAD patients (ABI 0.4-0.9) underwent contrast-enhanced perfusion MRI of the calf before and after plantar-flexion exercise using an MR-compatible pedal at 50 rpm for up to 20 minutes or until limiting symptoms. Contrast-enhanced first-pass images were obtained on a 3T Siemens Trio scanner by infusion of 0.1mM/kg of gadolinium-DTPA followed by a 20 mL saline flush at 4 mL/ second. A spoiled gradient echo dual contrast sequence with slices positioned 32 mm apart allowed for simultaneous acquisition of arterial input and muscle perfusion images. Time-intensity curves (TIC) were generated using ARGUS software (Siemens) for arterial input and the muscle group with the highest signal intensity (tissue function, TF). PI was measured as ratio of the slopes of the TF TIC/arterial input TIC. PR was defined as exercise TF/resting TF. PIR was calculated as exercise PI/rest PI. Ten of the controls and all 3 patients underwent repeat studies on a separate day. For 7 controls and all patients, measurements were normalized to proton density.

Late gadolinium enhancement can identify focal fibrosis, but cannot evaluate diffuse myocardial fibrosis. Multiple methods have been used to determine the partition coefficient (λ) and volume of distribution (Vd) of gadolinium to quantify diffuse myocardial fibrosis, including first-pass and T1 mapping based techniques. These two techniques have not been directly compared in the same subjects.

The destruction and dysfunction of pancreatic β-cells are at the root of diabetes mellitus. Magnetic resonance imaging (MRI ), a non-invasive imaging modality, may play an important role in assessing transplanted islets as well as β-cell mass and function. In addition to conventional MRI of anatomical structure and function, recent advances have led to the development and application of MRI for targeted molecular and cellular imaging. Pancreatic islets incubated ex vivo with superparamagnetic iron oxide particles can be visualized as signal hypointensity on MR images, which allows monitoring of viable transplanted islets. β-cells labelled in vivo with Mn2+ ions can be measured as signal hyperintensity on MR images, since Mn2+ ions enter β-cells through voltage-gated Ca2+ channels. Compartmental models that describe Mn2+ distribution in the pancreas may provide quantitative measurements of β-cell mass and function.

Pancreatic β-cell imaging would be useful in monitoring the progression of and therapies for diabetes. The purpose of this study was to develop and evaluate quantitative β-cell MRI using manganese (Mn(2+)) labeling of β cells, T1 mapping, and a two-site water exchange model. Normal, pharmacologically-treated, and severely diabetic mice underwent injection of MnCl(2). Pancreatic water proton T1 relaxation was measured using Look-Locker MRI, and two-site water exchange analysis was used to estimate model parameters including the intracellular water proton relaxation rate constant (R1(ic)) and the intracellular fraction as indicators of β-cell function and mass, respectively. Logarithmic plots of T1 relaxation revealed two distinct proton pools relaxing with different T1s, and the two-site water exchange model fit the measured T1 relaxation data better than a monoexponential model. The intracellular R1(ic) time course revealed the kinetics of β-cell Mn(2+) labeling. Pharmacological treatments with nifedipine, tolbutamide, and diazoxide altered R1(ic), indicating that beta cell function was a determinant of Mn(2+) uptake. Intracellular fraction was significantly higher in mice with normal β cell mass than in diabetic mice (14.9% vs. 14.4%, P < 0.05). Two-site water exchange analysis of T1 relaxation of the Mn(2+)-enhanced pancreas is a promising method for quantifying β cell volume fraction and function.

Loss of β-cell function in type 1 and type 2 diabetes leads to metabolic dysregulation and inability to maintain normoglycemia. Noninvasive imaging of β-cell function in vivo would therefore provide a valuable diagnostic and research tool for quantifying progression to diabetes and response to therapeutic intervention. Because manganese (Mn2+) is a longitudinal relaxation time (T1)-shortening magnetic resonance imaging (MRI) contrast agent that enters cells such as pancreatic β-cells through voltage-gated calcium channels, we hypothesized that Mn2+-enhanced MRI of the pancreas after glucose infusion would allow for noninvasive detection of β-cell function in vivo. To test this hypothesis, we administered glucose and saline challenges intravenously to normal mice and mice given high or low doses of streptozotocin (STZ) to induce diabetes. Serial inversion recovery MRI was subsequently performed after Mn2+ injection to probe Mn2+ accumulation in the pancreas. Time-intensity curves of the pancreas (normalized to the liver) fit to a sigmoid function showed a 51% increase in signal plateau height after glucose stimulation relative to saline ( P < 0.01) in normal mice. In diabetic mice given a high dose of STZ, only a 9% increase in plateau signal intensity was observed after glucose challenge ( P = not significant); in mice given a low dose of STZ, a 20% increase in plateau signal intensity was seen after glucose challenge ( P = 0.02). Consistent with these imaging findings, the pancreatic insulin content of high- and low-dose STZ diabetic mice was reduced about 20-fold and 10-fold, respectively, compared with normal mice. We conclude that Mn2+-enhanced MRI demonstrates excellent potential as a means for noninvasively monitoring β-cell function in vivo and may have the sensitivity to detect progressive decreases in function that occur in the diabetic disease process.

Background: Ischemia propagates as a wave front from the endocardial (ENDO) to the epicardial (EPI) surface. Normally, myocardial blood flow (MBF) is higher in the ENDO than EPI. We hypothesized that the ENDO/EPI ratio could differentiate the severity of coronary stenoses in a clinical patient population. Methods: Perfusion CMR was performed in 29 patients within 30 days of x-ray angiography and quantitative coronary analysis. During adenosine infusion and at rest, dual boluses of Gd-DTPA were infused (4ml/s) to quantify arterial input function (0.0075mM/kg) and tissue perfusion (0.075mM/kg) in 3 short axis slices using hybrid gradient echo/echo planar imaging. ENDO and EPI MBF for rest and stress were estimated by determining the peak amplitude of the impulse response derived from Fermi function deconvolution. Stress and rest ENDO/EPI ratios were calculated and then corrected (corr) for rate-pressure product (RPP) using the formula ENDO/EPI * (SBP*HR*10 −4 ). Results: Coronary stenosis (CS) >50% was present in 23 of 29 patients. Hypertension, diabetes, and dyslipidemia were present in 23, 9, and 26 patients, respectively. Stress corrENDO/EPI (mean±SE) was inversely related to CS (CS70% = 1.149 ± 0.039; p ). The relationship persisted after exclusion of the 56 segments with a myocardial scar (p Conclusions: Stress corrENDO/EPI is inversely related to the severity of CS. Quantitative stress endo/epi ratios can distinguish intermediate from severe stenoses in patients with known or suspected CS.

Quantitative first-pass magnetic resonance (MR) imaging studies assist in characterizing the severity of ischemic heart disease. Cardiac motion due to a patient's difficulty in maintaining the required breath hold is often severe, making registration necessary. In this paper we present a novel automatic affine registration algorithm. The algorithm utilizes an affine active contour to determine affine registration errors in first-pass MR studies. We compare our results to the original unregistered studies and a normalized cross-correlation registration method

Summary We used first-pass contrast-enhanced MRI to quantatively measure the myocardial Ktrans, a parameter indicating myocardial perfusion and vascular permeability, in mice with or without vasodilation. We measured a significant increase in myocardial Ktrans with vasodilation. We believe this may be the first report showing that first-pass imaging can quantify increased myocardial perfusion in mice relative to baseline. Background First-pass contrast-enhanced MRI is a well-established technique for quantifying myocardial perfusion in humans and large animals and has recently emerged as a viable tool for quantifying myocardial perfusion in mice [1-3]. Applied in mice, first-pass MRI could be used to assess the roles of individual genes in perfusion and vascular permeability. The purpose of this study was test the hypothesis that first-pass contrast-enhanced MRI can measure increased myocardial perfusion after administration of a vasodilator in mice. Methods Imaging was performed on a 7T Clinscan MR system equipped with a gradient system having a full strength of 650mT/m and as lew rate of 6666 mT/m/ms, and using a 30mm diameter birdcage RF coil. A saturationrecovery spiral sequence was employed, with TE = 0.36 ms, TR = 3.9ms, interleaves = 14, FOV = 25.6 x 25.6mm, matrix = 128x128, saturation delay = 40 ms, alpha = 20°, and slice thickness = 1mm. Data acquisition required 55 ms/image, approximately 40% of the murine R-R interval, and was placed in the latter part of the cardiac cycle. C57Bl6/J mice were imaged with (n=5) and without (n=5) an intraperitoneal bolus injection of the vasodilator ATL313 (Adenosine Therapeutics, Charlottesville, VA). First-pass images were acquired for one mid-ventricular short-axis slice. A dual-bolus gadolinium injection technique was used, acquiring the arterial input and tissue functions (AIF and TF) in separate scans. Myocardial Ktrans, the product of myocardial perfusion and the first-pass extraction fraction of gadolinium, was quantified using a standard Kety model deconvolution method. Results

Background Myocardial blood flow (MBF) imaging in gene-modified mice may be used to elucidate molecular mechanisms that underlie coronary vascular function and dysfunction. First pass Gd-enhanced MRI is well-established in humans and has been recently investigated in mice[1-3]. The rapid heart rate and small size of the heart present challenges to performing quantitative first pass imaging in mice. A dual contrast acquisition simplifies the procedure (one Gd injection) and may provide more accurate results because the arterial input function (AIF) and tissue function (TF) are acquired under identical conditions. We developed a compressed sensing (CS)-accelerated first pass sequence for mice with a dual contrast acquisition.

Background Quantitative contrast enhanced MRI (CE-MRI) may be valuable for calf perfusion assessment in peripheral arterial disease (PAD). The Kety equation describes the dynamic relationship between the concentration of gadolinium (Gd) in tissue and in arterial blood. ktrans is the rate at which Gd enters the interstitial space and it is determined by blood flow (F) as well as the Gd extraction rate (E). We aimed to measure ktrans at peak exercise in healthy (NL) and PAD subjects.