Enterocolic lymphocytic phlebitis: a rare pathology in children

Enterocolic lymphocytic phlebitis (ELP) is a rare pathology, usually seen in the adult population. The condition affects the venous vasculature of the intestine sparing the arteries and lymphatics. It is commonly identified histologically after surgical resection making the preoperative diagnosis a clinical challenge. As the condition can lead to intestinal ischaemia and necrosis, surgical resection of the affected segment is the treatment of choice. We report the case of a 9-year-old girl who presented with a 2-day history of lower abdominal pain and anorexia. The initial diagnosis of appendicitis was made clinically and the patient underwent a diagnostic laparoscopy . The appendix was macroscopically normal and there were no other obvious intra-abdominal pathologies to account for her presenting complaints . The appendix was removed, as per the preoperative discussion and consent from parents. She recovered well and was discharged home the following day. The histological examination of the appendix demonstrated ELP. We describe this rare clinical entity in a child especially in view of the scarce published literature in the paediatric population.

Venous malformation vessels are improperly specified and hyperproliferative

Venous malformations (VMs) are slow-flow malformations of the venous vasculature and are the most common type of vascular malformation with a prevalence of 1%. Germline and somatic mutations have been shown to contribute to VM pathogenesis, but how these mutations affect VM pathobiology is not well understood. The goal of this study was to characterize VM endothelial and mural cell expression by performing a comprehensive expression analysis of VM vasculature. VM specimens (n = 16) were stained for pan-endothelial, arterial, venous, and endothelial progenitor cell proteins; proliferation was assessed with KI67. Endothelial cells in the VM vessels were abnormally orientated and improperly specified, as seen by the misexpression of both arterial and endothelial cell progenitor proteins not observed in control vessels. Consistent with arterialization of the endothelial cells, VM vessels were often surrounded by multiple layers of disorganized mural cells. VM endothelium also had a significant increase in proliferative endothelial cells, which may contribute to the dilated channels seen in VMs. Together the expression analysis indicates that the VM endothelium is misspecified and hyperproliferative, suggesting that VMs are biologically active lesions, consistent with clinical observations of VM progression over time.

Sickle Cell Disease: A Paradigm for Venous Thrombosis Pathophysiology

Venous thromboembolism (VTE) is an important cause of vascular morbidity and mortality. Many risk factors have been identified for venous thrombosis that lead to alterations in blood flow, activate the vascular endothelium, and increase the propensity for blood coagulation. However, the precise molecular and cellular mechanisms that cause blood clots in the venous vasculature have not been fully elucidated. Patients with sickle cell disease (SCD) demonstrate all the risk factors for venous stasis, activated endothelium, and blood hypercoagulability, making them particularly vulnerable to VTE. In this review, we will discuss how mouse models have elucidated the complex vascular pathobiology of SCD. We review the dysregulated pathways of inflammation and coagulation in SCD and how the resultant hypercoagulable state can potentiate thrombosis through down-regulation of vascular anticoagulants. Studies of VTE pathogenesis using SCD mouse models may provide insight into the intersection between the cellular and molecular processes involving inflammation and coagulation and help to identify novel mechanistic pathways.

High resolution atlas of the venous brain vasculature from 7 T quantitative susceptibility maps

The vascular organization of the human brain can determine neurological and neurophysiological functions, yet thus far it has not been comprehensively mapped. Aging and diseases such as dementia are known to be associated with changes to the vasculature and normative data could help detect these vascular changes in neuroimaging studies. Furthermore, given the well-known impact of venous vessels on the blood oxygen level dependent (BOLD) signal, information about the common location of veins could help detect biases in existing datasets. In this work, a quantitative atlas of the venous vasculature using quantitative susceptibility maps (QSM) acquired with a 0.6 mm isotropic resolution is presented. The Venous Neuroanatomy (VENAT) atlas was created from 5 repeated 7 Tesla MRI measurements in young and healthy volunteers (n = 20, 10 females, mean age = 25.1 ± 2.5 years) using a two-step registration method on 3D segmentations of the venous vasculature. This cerebral vein atlas includes the average vessel location, diameter (mean: 0.84 ± 0.33 mm) and curvature (0.11 ± 0.05 mm−1) from all participants and provides an in vivo measure of the angio-architectonic organization of the human brain and its variability. This atlas can be used as a basis to understand changes in the vasculature during aging and neurodegeneration, as well as vascular and physiological effects in neuroimaging.

Classic Papers Revisited: My Love Affair with the Venous System

The Pathophysiology of Aortic Cross-clamping and Unclamping. By Gelman S. ANesthesiology 1995; 82:1026–60. Reprinted with permission. Aortic cross-clamping (AoX) and unclamping are associated with severe hemodynamic disturbances in virtually all organs and systems. The main hemodynamic changes induced by AoX result from an increase in impedance to aortic flow, an increase in systemic vascular resistance and afterload, blood volume redistribution caused by collapse and constriction of venous vasculature distal to the aortic clamp, and a subsequent increase in preload. Preload may not increase if the aorta is clamped distal to the celiac artery; in that case, blood volume from distal venous vasculature may be redistributed to the splanchnic vasculature without associated increases in preload. Increases in afterload and preload demand an increase in contractility, which results in an autoregulatory increase in coronary blood flow. Without increases in coronary blood flow and myocardial contractility, decompensation may occur. Aortic cross-clamping is associated with the formation and release of many mediators which constitute a double-edged sword: they may mitigate or aggravate the harmful hemodynamic effects of AoX and unclamping. Injuries to the lungs, kidneys, spinal cord, or abdominal viscera are caused mainly by ischemia and reperfusion of organs distal to aortic cross-clamping. A clear understanding of the pathophysiologic mechanisms involved in these processes should help to promote rational, well-focused, and effective measures to prevent and treat homeostatic disturbances occurring during AoX and unclamping.

Oh, the places you'll go! My many colored serotonin (apologies to Dr. Seuss)

Serotonin [5-hydroxytryptamine (5-HT)] has a truly fascinating history in the cardiovascular world. Discovered in the blood, 5-HT has long been appropriately regarded as a vasoconstrictor. A multitude of in vitro studies of isolated vessels support that addition of 5-HT causes vascular contraction. In only a few cases was 5-HT a vasodilator. Moreover, the potency and threshold of 5-HT causing contraction is increased in arteries from hypertensive vs. normotensive subjects, both animal and human. As such, we and others have hypothesized that 5-HT would contribute to hypertension by elevating arterial tone. In stark contrast to these decades of findings, we observed that a chronic infusion of 5-HT into conscious rats caused a reduction in blood pressure and nearly normalized blood pressure of experimentally hypertensive rats. Going back to the early work of Irvine Page, one of the scientists who discovered 5-HT, reveals an early recognized but never understood ability of 5-HT to reduce systemic blood pressure. Our laboratory, in collaboration with colleagues around the world, has dedicated itself to understanding the mechanisms of 5-HT-induced reduction in blood pressure. This manuscript takes you through a brief history of the discovery of 5-HT, in vitro serotonergic pharmacology of blood vessels, in vivo work with 5-HT and our studies that suggests the venous vasculature, potentially in combination with small arterioles, may be important to the actions of 5-HT in reducing blood pressure. 5-HT has certainly ended up in a place I never expected it to go.

Background-Suppressed MR Venography of the Brain Using Magnitude Data: A High-Pass Filtering Approach

Conventional susceptibility-weighted imaging (SWI) uses both phase and magnitude data for the enhancement of venous vasculature and, thus, is subject to signal loss in regions with severe field inhomogeneity and in the peripheral regions of the brain in the minimum-intensity projection. The purpose of this study is to enhance the visibility of the venous vasculature and reduce the artifacts in the venography by suppressing the background signal in postprocessing. A high-pass filter with an inverted Hamming window or an inverted Fermi window was applied to the Fourier domain of the magnitude images to enhance the visibility of the venous vasculature in the brain after data acquisition. The high-pass filtering approach has the advantages of enhancing the visibility of small veins, diminishing the off-resonance artifact, reducing signal loss in the peripheral regions of the brain in projection, and nearly completely suppressing the background signal. The proposed postprocessing technique is effective for the visualization of small venous vasculature using the magnitude data alone.