Objective A population-based point-prevalence study was conducted to determine the prevalence of peripheral arterial disease (PAD) in Sweden, with special attention to critical limb ischemia and sex ...differences. Methods An age-standardized randomly selected population sample of 8000 women and men, aged 60 to 90 years, from four different regions in Sweden was invited to participate. The sample had the same age and gender distribution as the Swedish population in this age group. Participating subjects completed questionnaires on medical history, present medication, and symptoms, and their ankle-brachial index (ABI) was measured. Subjects were analyzed for presence of PAD according to reported symptoms and an ABI <0.9. Results A total of 5080 subjects were included, giving a participation rate of 64%. The prevalence of any PAD, asymptomatic PAD, intermittent claudication, and severe limb ischemia was, respectively, 18% (95% confidence interval CI, 16% to 20%) 11% (9% to 13%), 7% (6.5 to 7%) and 1.2% (1% to 1.5%). Women had a higher prevalence than men when PAD was diagnosed with ABI only; that is, asymptomatic PAD (12.6% vs 9.4%, P = .03) and severe limb ischemia (1.5% vs 0.8%, P < .008). The prevalence of any PAD was 7.9% in the age group 60 to 65 years and increased to 47.2% among the age group 85 to 90 years. Severe limb ischemia occurred in 0.3% in the youngest age group, was highest in the age group 80 to 84 years at 3.3%, and declined to 2.5% among the oldest. The prevalence of PAD differed between regions ( P < .0001). Conclusions PAD is common in Sweden, and almost a fifth of all elderly individuals have some stage of this disease. Women are more often afflicted than men. The prevalence of severe ischemia, as a measure of critical limb ischemia, is about 1% the population.
Vascular endothelium offers a variety of therapeutic targets for the treatment of cancer, cardiovascular diseases, inflammation, and oxidative stress. Significant research has been focused on ...developing agents to target the endothelium in diseased tissues. This includes identification of antibodies against adhesion molecules and neovascular expression markers or peptides discovered using phage display. Such targeting molecules also have been used to deliver nanoparticles to the endothelium of the diseased tissue. Here we report, based on in vitro and in vivo studies, that the specificity of endothelial targeting can be enhanced further by engineering the shape of ligand-displaying nanoparticles. In vitro studies performed using microfluidic systems that mimic the vasculature (synthetic microvascular networks) showed that rod-shaped nanoparticles exhibit higher specific and lower nonspecific accumulation under flow at the target compared with their spherical counterparts. Mathematical modeling of particle–surface interactions suggests that the higher avidity and specificity of nanorods originate from the balance of polyvalent interactions that favor adhesion and entropic losses as well as shear-induced detachment that reduce binding. In vivo experiments in mice confirmed that shape-induced enhancement of vascular targeting is also observed under physiological conditions in lungs and brain for nanoparticles displaying anti–intracellular adhesion molecule 1 and anti-transferrin receptor antibodies.
A major roadblock to successful organ bioengineering is the need for a functional vascular network within the engineered tissue. Here, we describe the fabrication of three‐dimensional, naturally ...derived scaffolds with an intact vascular tree. Livers from different species were perfused with detergent to selectively remove the cellular components of the tissue while preserving the extracellular matrix components and the intact vascular network. The decellularized vascular network was able to withstand fluid flow that entered through a central inlet vessel, branched into an extensive capillary bed, and coalesced into a single outlet vessel. The vascular network was used to reseed the scaffolds with human fetal liver and endothelial cells. These cells engrafted in their putative native locations within the decellularized organ and displayed typical endothelial, hepatic, and biliary epithelial markers, thus creating a liver‐like tissue in vitro. Conclusion: These results represent a significant advancement in the bioengineering of whole organs. This technology may provide the necessary tools to produce the first fully functional bioengineered livers for organ transplantation and drug discovery. (HEPATOLOGY 2011;53:604‐617)
RATIONALE:Janus kinase/signal transducer and activator of transcription (JAK/STAT) signals and their endogenous inhibitor, suppressor of cytokine signaling 3 (SOCS3), in vascular endothelial cells ...(ECs) reportedly dominate the pathological angiogenesis. However, how these inflammatory signals are potentiated during pathological angiogenesis has not been fully elucidated. We suspected that an intracellular protease calpain, which composes the multifunctional proteolytic systems together with its endogenous inhibitor calpastatin (CAST), contributes to the JAK/STAT regulations.
OBJECTIVE:To specify the effect of EC calpain/CAST systems on JAK/STAT signals and their relationship with pathological angiogenesis.
METHODS AND RESULTS:The loss of CAST, which is ensured by several growth factor classes, was detectable in neovessels in murine allograft tumors, some human malignant tissues, and oxygen-induced retinopathy lesions in mice. EC-specific transgenic introduction of CAST caused downregulation of JAK/STAT signals, upregulation of SOCS3 expression, and depletion of vascular endothelial growth factor (VEGF)-C, thereby counteracting unstable pathological neovessels and disease progression in tumors and oxygen-induced retinopathy lesions in mice. Neutralizing antibody against VEGF-C ameliorated pathological angiogenesis in oxygen-induced retinopathy lesions. Small interfering RNA–based silencing of endogenous CAST in cultured ECs facilitated μ-calpain–induced proteolytic degradation of SOCS3, leading to VEGF-C production through amplified interleukin-6–driven STAT3 signals. Interleukin-6–induced angiogenic tube formation in cultured ECs was accelerated by CAST silencing, which is suppressible by pharmacological inhibition of JAK/STAT signals, antibody-based blockage of VEGF-C, and transfection of calpain-resistant SOCS3, whereas transfection of wild-type SOCS3 exhibited modest angiostatic effects.
CONCLUSIONS:Loss of CAST in angiogenic ECs facilitates μ-calpain–induced SOCS3 degradation, which amplifies pathological angiogenesis through interleukin-6/STAT3/VEGF-C axis.
RATIONALE:Remote ischemic preconditioning (rIPC) with short episodes of ischemia/reperfusion (I/R) of an organ remote from the heart is a powerful approach to protect against myocardial I/R injury. ...The signal transduction pathways for the cross talk between the remote site and the heart remain unclear in detail.
OBJECTIVE:To elucidate the role of circulating nitrite in cardioprotection by rIPC.
METHODS AND RESULTS:Mice were subjected to 4 cycles of no-flow ischemia with subsequent reactive hyperemia within the femoral region and underwent in vivo myocardial I/R (30 minutes/5 minutes or 24 hours). The mouse experiments were conducted using genetic and pharmacological approaches. Shear stress–dependent stimulation of endothelial nitric oxide synthase within the femoral artery during reactive hyperemia yielded substantial release of nitric oxide, subsequently oxidized to nitrite and transferred humorally to the myocardium. Within the heart, reduction of nitrite to nitric oxide by cardiac myoglobin and subsequent S-nitrosation of mitochondrial membrane proteins reduced mitochondrial respiration, reactive oxygen species formation, and myocardial infarct size. Pharmacological and genetic inhibition of nitric oxide/nitrite generation by endothelial nitric oxide synthase at the remote site or nitrite bioactivation by myoglobin within the target organ abrogated the cardioprotection by rIPC. Transfer experiments of plasma from healthy volunteers subjected to rIPC of the arm identified plasma nitrite as a cardioprotective agent in isolated Langendorff mouse heart preparations exposed to I/R.
CONCLUSIONS:Circulating nitrite derived from shear stress–dependent stimulation of endothelial nitric oxide synthase at the remote site of rIPC contributes to cardioprotection during I/R.
CLINICAL TRIAL REGISTRATION—URLhttp://www.clinicaltrials.gov. Unique identifierNCT01259739.
Background Transcranial magnetic stimulation (TMS) to the left dorsolateral prefrontal cortex (DLPFC) is used clinically for the treatment of depression. However, the antidepressant mechanism remains ...unknown and its therapeutic efficacy remains limited. Recent data suggest that some left DLPFC targets are more effective than others; however, the reasons for this heterogeneity and how to capitalize on this information remain unclear. Methods Intrinsic (resting state) functional magnetic resonance imaging data from 98 normal subjects were used to compute functional connectivity with various left DLPFC TMS targets employed in the literature. Differences in functional connectivity related to differences in previously reported clinical efficacy were identified. This information was translated into a connectivity-based targeting strategy to identify optimized left DLPFC TMS coordinates. Results in normal subjects were tested for reproducibility in an independent cohort of 13 patients with depression. Results Differences in functional connectivity were related to previously reported differences in clinical efficacy across a distributed set of cortical and limbic regions. Dorsolateral prefrontal cortex TMS sites with better clinical efficacy were more negatively correlated (anticorrelated) with the subgenual cingulate. Optimum connectivity-based stimulation coordinates were identified in Brodmann area 46. Results were reproducible in patients with depression. Conclusions Reported antidepressant efficacy of different left DLPFC TMS sites is related to the anticorrelation of each site with the subgenual cingulate, potentially lending insight into the antidepressant mechanism of TMS and suggesting a role for intrinsically anticorrelated networks in depression. These results can be translated into a connectivity-based targeting strategy for focal brain stimulation that might be used to optimize clinical response.
The neuropeptide oxytocin (OXT) plays an important role in complex socio-affective behaviours such as affiliation, attachment, stress and anxiety. Previous studies have focused on the amygdala as an ...important target of OXT's effects. However, the effects of OXT on connectivity of the amygdala with cortical regions such as medial frontal cortex, an important mediator of social cognition and emotion regulation, remain unexplored. In a randomized, double-blind, cross-over design, 15 volunteers received intranasal OXT or placebo prior to resting-state functional magnetic resonance imaging. OXT significantly increased connectivity between both amygdalae and rostral medial frontal cortex (rmFC), while having only negligible effects on coupling with other brain regions. These results demonstrate that OXT is a robust and highly selective enhancer of amygdala connectivity with rmFC, a region critical to social cognition and emotion regulation, and add to our understanding of the neural mechanisms by which OXT modulates complex social and cognitive behaviours.
Intravital fluorescence imaging of vasculature morphology and dynamics in the brain and in tumors with large penetration depth and high signal‐to‐background ratio (SBR) is highly desirable for the ...study and theranostics of vascular‐related diseases and cancers. Herein, a highly bright fluorophore (BTPETQ) with long‐wavelength absorption and aggregation‐induced near‐infrared (NIR) emission (maximum at ≈700 nm) is designed for intravital two‐photon fluorescence (2PF) imaging of a mouse brain and tumor vasculatures under NIR‐II light (1200 nm) excitation. BTPETQ dots fabricated via nanoprecipitation show uniform size of around 42 nm and a high quantum yield of 19 ± 1% in aqueous media. The 2PF imaging of the mouse brain vasculatures labeled by BTPETQ dots reveals a 3D blood vessel network with an ultradeep depth of 924 µm. In addition, BTPETQ dots show enhanced 2PF in tumor vasculatures due to their unique leaky structures, which facilitates the differentiation of normal blood vessels from tumor vessels with high SBR in deep tumor tissues. Moreover, the extravasation and accumulation of BTPETQ dots in deep tumor (more than 900 µm) is visualized under NIR‐II excitation. This study highlights the importance of developing NIR‐II light excitable efficient NIR fluorophores for in vivo deep tissue and high contrast tumor imaging.
Aggregation‐induced emission dots (AIE dots) with ultrabright NIR‐I emission (peak at ≈700 nm and a quantum yield of 19%) are synthesized for NIR‐II (1200 nm) excited in vivo two‐photon fluorescence (2PF) imaging of deep tumor vasculatures. The tumor vasculatures labeled with AIE dots exhibit enhanced 2PF, which leads to the tumor blood vessels being able to be distinguished from normal ones in deep tissues.
Mass spectrometry imaging provides a powerful approach for the direct analysis and spatial visualization of molecules in tissue sections. Using matrix-assisted laser desorption/ionization mass ...spectrometry, intact protein imaging has been widely investigated for biomarker analysis and diagnosis in a variety of tissue types and diseases. However, blood-rich or highly vascular tissues present a challenge in molecular imaging due to the high ionization efficiency of hemoglobin, which leads to ion suppression of endogenous proteins. Here, we describe a protocol to selectively reduce hemoglobin signal in blood-rich tissues that can easily be integrated into mass spectrometry imaging workflows.
Angiogenesis-mediated progression of micrometastasis to lethal macrometastasis is the major cause of death in cancer patients. Here, using mouse models of pulmonary metastasis, we identify bone ...marrow (BM)-derived endothelial progenitor cells (EPCs) as critical regulators of this angiogenic switch. We show that tumors induce expression of the transcription factor Id1 in the EPCs and that suppression of Id1 after metastatic colonization blocked EPC mobilization, caused angiogenesis inhibition, impaired pulmonary macrometastases, and increased survival of tumor-bearing animals. These findings establish the role of EPCs in metastatic progression in preclinical models and suggest that selective targeting of EPCs may merit investigation as a therapy for cancer patients with lung metastases.
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