Perivascular Adventitia Research Articles

PNEUMOMEDIASTINUM FROM SPIROMETRY AND RESPIRATORY FUNCTION TESTING AFTER MEDIAN STERNOTOMY AND THYMECTOMY: A CASE REPORT

SESSION TITLE: Global Case Report Posters SESSION TYPE: Global Case Reports PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Pneumomediastinum is the presence of air within the mediastinum. Causes include parenchymal lung disease, violent coughing, and vomiting and chest surgery. Spirometry testing is a rare cause of pneumomediastinum. We report a case of pneumomediastinum due to pulmonary function testing and spirometry in a man who underwent thymic surgery. CASE PRESENTATION: A 52 year old man underwent median sternotomy and thymectomy for a 9x7cm thymoma discovered after diagnosis of myasthenia gravis. Chest drains were removed by post-operative day (POD) 2. The patient received chest physiotherapy, incentive spirometry and twice daily negative inspiratory force (NIF) and forced vital capacity (FVC) measurements as recommended by Neurology. On POD 5, he reported a change in voice quality and facial swelling. Subcutaneous crepitus was palpable over the right chest, neck and cheek. A computed tomographic (CT) study of the thorax showed extensive pneumomediastinum, pneumopericardium and subcutaneous emphysema extending to the right temporal fossa. Upon review of our patient’s NIF and FVC measurements, he was found to have an increased FVC daily with an FVC of 3L prior to the onset of his symptoms. The patient was commenced on bed rest with limited ambulation around his cubicle. Spirometry and the NIF and FVC measurements were stopped and he was commenced on empirical antibiotics. He reported improvement of his facial swelling within 24 hours and daily chest radiographs demonstrated improvement in the subcutaneous emphysema. The patient remained clinically well and was discharged on POD 8 with a course of oral antibiotics. DISCUSSION: The pathophysiology of pneumomediastinum suggests that following alveolar rupture, air enters the perivascular adventitia and dissects proximally into the mediastinum. Pneumomediastinum following chest surgery should prompt the clinician to rule out pneumothorax and mediastinitis and monitor for obstructive symptoms, air embolism and subcutaneous emphysema. When significant pathology has been excluded, treatment is directed towards symptom relief. In our patient, we postulate that the rapid increase in lung volume and pressure changes in the alveolus from the inspiratory function tests and incentive spirometry, coupled with breaches of the pleura and pericardium during surgery, had caused air to dissect into the subcutaneous plane, mediastinum and pericardial space. CONCLUSIONS: Incentive spirometry helps prevent postoperative pulmonary complications and aids recovery of pulmonary function in patients undergoing thoracic surgery. Our case highlights the need to be aware of potential complications of spirometry and pulmonary function testing in motivated patients, especially following thoracic surgery. Reference #1: Manco, JC, Terra-Filho, J, and Silva, GA. Pneumomediastinum, pneumothorax and subcutaneous emphysema following the measurement of maximal expiratory pressure in a normal subject. Chest. 1990; 98: 1530–1532 DISCLOSURES: No relevant relationships by Atasha Asmat, source=Web Response No relevant relationships by Shaun Chan, source=Web Response No relevant relationships by Jacqueline Chua, source=Web Response

First detection of Erysipelothrix sp. infection in western mosquitofish Gambusia affinis inhabiting catfish aquaculture ponds in Mississippi, USA.

Native and introduced fish can serve as reservoirs for pathogens of cultured fish species. In the current study, 351 archived western mosquitofish Gambusia affinis collected from experimental catfish production ponds in Mississippi, USA, were surveyed histologically to evaluate their potential as vectors for fish pathogens. In addition to epitheliocystis and multiple metazoan parasites, 8 fish had widespread basophilic colonies of small Gram-positive rods associated primarily with stroma supporting the skeletal muscle and bone, as well as connective tissue components of other tissues and organ systems, such as perivascular adventitia and basement membranes. These findings were consistent with spaC-type Erysipelothrix sp. infections in ornamental fish cultured in the USA. The 16S rRNA, gyrase B (gyrB), and surface protective antigen (spa) genes were amplified and sequenced from bacterial colonies excised from paraffin-embedded tissue sections using laser capture microdissection. Molecular data confirmed the identity of a spaC-type Erysipelothrix sp., which grouped phylogenetically with spaC-type Erysipelothrix sp. from diseased ornamental fish. Given the significance of commercial catfish aquaculture in the southeastern USA and the widespread distribution of mosquitofish in catfish ponds throughout the region, infectivity trials with channel catfish Ictalurus punctatus were conducted. Catfish fingerlings were exposed to a spaC-type Erysipelothrix sp. isolate by intracoelomic injection and gavage. No mortality was observed in catfish exposed by either route, and surviving fish demonstrated no significant histopathologic lesions, suggesting channel catfish have low susceptibility to the bacteria. Further research is warranted to investigate the susceptibility of other cultured fish species to this emergent fish pathogen.

Maternal uterine artery VEGF gene therapy for treatment of intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a serious pregnancy complication affecting approximately 8% of all pregnancies. The aetiology is believed to be insufficient maternal uteroplacental perfusion which prevents adequate nutrient and oxygen availability for the fetus. There is no treatment that can improve uteroplacental perfusion and thereby increase fetal growth in the uterus.Maternal uterine artery gene therapy presents a promising treatment strategy for IUGR, with the use of adenoviral vectors encoding for proteins such as Vascular Endothelial Growth Factor (VEGF) demonstrating improvements in fetal growth and neonatal outcome in preclinical studies. Mechanistically, maternal VEGF gene therapy delivered to the uterine arteries increases uterine blood flow and enhances vascular relaxation short term, while reducing vascular contractility long term. It also leads to vascular remodeling with increased endothelial cell proliferation in the perivascular adventitia of uterine arteries. Safety assessments suggest no vector spread to the fetus and no adverse risk to the mother or fetus; a clinical trial is in development. This article assesses research into VEGF maternal uterine artery directed gene therapy for IUGR, investigating the use of transgenes and vectors, their route of administration in obstetrics, and the steps that will be needed to take this treatment modality into the clinic.

Role of Axl in T-Lymphocyte Survival in Salt-Dependent Hypertension.

Survival of immune and nonimmune cells relies on Axl, a receptor tyrosine kinase, which is implicated in hypertension. Activated T lymphocytes are involved in regulation of high blood pressure. The goal of the study was to investigate the role of Axl in T-lymphocyte functions and its contribution to salt-dependent hypertension. We report increased apoptosis in peripheral blood from Axl(-/-) mice because of lower numbers of white blood cells mostly lymphocytes. In vitro studies showed modest reduction in interferon gamma production in Axl(-/-) type 1 T helper cells. Axl did not affect basic proliferation capacity or production of interleukin 4 in Axl(-/-) type 2 T helper cells. However, competitive repopulation of Axl(-/-) bone marrow or adoptive transfer of Axl(-/-) CD4(+) T cells to Rag1(-/-) mice showed robust effect of Axl on T lymphocyte expansion in vivo. Adoptive transfer of Axl(-/-) CD4(+) T cells was protective in a later phase of deoxycorticosterone-acetate and salt hypertension. Reduced numbers of CD4(+) T cells in circulation and in perivascular adventitia decreased vascular remodeling and increased vascular apoptosis in the late phase of hypertension. These findings suggest that Axl is critical for survival of T lymphocytes, especially during vascular remodeling in hypertension.

Isolation, Culture, and Characterization of Vascular Smooth Muscle Cells.

Smooth muscle cells (SMC) are the predominant cell type involved in the pathogenesis of atherosclerosis, vascular calcification and restenosis after angioplasty; however, they are also important in the de novo formation of blood vessels through differentiation of mesenchymal cells under the influence of mediators secreted by endothelial cells. In angiogenesis, vascular SMC are formed by proliferation of existing SMC or maturation and differntiation of pericytes. Experimental findings have demonstrated a potential role of putative smooth muscle progenitor cells in the circulation or within adult tissues and the perivascular adventitia in the development of atherosclerotic plaques, restenosis and angiogenesis. Modulation of vascular smooth muscle phenotype, SMC migration and hypertrophy are now recognized as key events in the development of vascular diseases. This has led to an increase in experimental research on SMC function in response to growth factors, extracellular matrix components, modified lipoproteins, biomechanical forces and other pro-atherogenic and pro-angiogenic mediators to address the cellular mechanisms involved. This chapter highlights well established methodologies used for vascular SMC and pericyte isolation and culture as well as their characterisation. A better understanding of vascular SMC and pericyte biology and their phenotypic modulation is required to identify therapeutic strategies to target angiogenesis and treat cardiovascular diseases.

Uteroplacental Adenovirus Vascular Endothelial Growth Factor Gene Therapy Increases Fetal Growth Velocity in Growth-Restricted Sheep Pregnancies

Fetal growth restriction (FGR) occurs in ∼8% of pregnancies and is a major cause of perinatal mortality and morbidity. There is no effective treatment. FGR is characterized by reduced uterine blood flow (UBF). In normal sheep pregnancies, local uterine artery (UtA) adenovirus (Ad)-mediated overexpression of vascular endothelial growth factor (VEGF) increases UBF. Herein we evaluated Ad.VEGF therapy in the overnourished adolescent ewe, an experimental paradigm in which reduced UBF from midgestation correlates with reduced lamb birthweight near term. Singleton pregnancies were established using embryo transfer in adolescent ewes subsequently offered a high intake (n=45) or control intake (n=12) of a complete diet to generate FGR or normal fetoplacental growth, respectively. High-intake ewes were randomized midgestation to receive bilateral UtA injections of 5×10¹¹ particles Ad.VEGF-A165 (n=18), control vector Ad.LacZ (n=14), or control saline (n=13). Fetal growth/well-being were evaluated using serial ultrasound. UBF was monitored using indwelling flowprobes until necropsy at 0.9 gestation. Vasorelaxation, neovascularization within the perivascular adventitia, and placental mRNA expression of angiogenic factors/receptors were examined using organ bath analysis, anti-vWF immunohistochemistry, and qRT-PCR, respectively. Ad.VEGF significantly increased ultrasonographic fetal growth velocity at 3-4 weeks postinjection (p=0.016-0.047). At 0.9 gestation fewer fetuses were markedly growth-restricted (birthweight >2SD below contemporaneous control-intake mean) after Ad.VEGF therapy. There was also evidence of mitigated fetal brain sparing (lower biparietal diameter-to-abdominal circumference and brain-to-liver weight ratios). No effects were observed on UBF or neovascularization; however, Ad.VEGF-transduced vessels demonstrated strikingly enhanced vasorelaxation. Placental efficiency (fetal-to-placental weight ratio) and FLT1/KDR mRNA expression were increased in the maternal but not fetal placental compartments, suggesting downstream effects on placental function. Ad.VEGF gene therapy improves fetal growth in a sheep model of FGR, although the precise mechanism of action remains unclear.

Phenotypic characterization and in vivo localization of human adipose-derived mesenchymal stem cells.

Human adipose-derived mesenchymal stem cells (hADMSCs) are a potential cell source for autologous cell therapy due to their regenerative ability. However, detailed cytological or phenotypic characteristics of these cells are still unclear. Therefore, we determined and compared cell size, morphology, ultrastructure, and immunohistochemical (IHC) expression profiles of isolated hADMSCs and cells located in human adipose tissues. We also characterized the localization of these cells in vivo. Light microscopy examination at low power revealed that hADMSCs acquired a spindle-shaped morphology after four passages. Additionally, high power views showed that these cells had various sizes, nuclear contours, and cytoplasmic textures. To further evaluate cell morphology, transmission electron microscopy was performed. hADMSCs typically had ultrastructural characteristics similar to those of primitive mesenchymal cells including a relatively high nuclear/cytosol ratio, prominent nucleoli, immature cytoplasmic organelles, and numerous filipodia. Some cells contained various numbers of lamellar bodies and lipid droplets. IHC staining demonstrated that PDGFR and CD10 were constitutively expressed in most hADMSCs regardless of passage number but expression levels of α-SMA, CD68, Oct4 and c-kit varied. IHC staining of adipose tissue showed that cells with immunophenotypic characteristics identical to those of hADMSCs were located mainly in the perivascular adventitia not in smooth muscle area. In summary, hADMSCs were found to represent a heterogeneous cell population with primitive mesenchymal cells that were mainly found in the perivascular adventitia. Furthermore, the cell surface markers would be CD10/PDGFR. To obtain defined cell populations for therapeutic purposes, further studies will be required to establish more specific isolation methods.

The effects of local over-expression of VEGF on the uterine arteries and uterine artery endothelial cells of pregnant sheep

IntroductionImpaired utero-placental perfusion leads to fetal growth restriction. The authors have shown a significant increase in blood flow in the uterine arteries (UAs) of pregnant sheep and a significantly reduced...

Time Course of Changes in Nitric Oxide Synthases Following Subarachnoid Hemorrhage in Primates

P114 Nitric oxide (NO) may be important in vasospasm following subarachnoid hemorrhage (SAH). We evaluated the time course of changes in 3 isoforms of NO synthase (NOS) after SAH in monkeys. Right SAH was created and vasospasm was assessed on angiograms obtained at baseline and after 3, 7 and 14 days. Animals were euthanized at these times (n = 4 - 6 per time) and the right and left (control) middle cerebral arteries were removed. Levels of nNOS, eNOS and iNOS messenger ribonucleic acid (mRNA) and protein were measured by reverse transcriptase polymerase chain reaction and Western blotting. Angiography showed a 45 ± 13% (mean ± s.d., p < 0.05) decrease in middle cerebral artery diameter 3 days, a 41 ± 23% (p< 0.05) decrease 7 days and an insignificant 6 ± 14% decrease 14 days after SAH. The RNA for eNOS was significantly reduced (1.7 ± 0.5-fold) 7 days after SAH. There was a significant, 1.7 ± 0.2-fold reduction in eNOS protein on days 3 and 7 after SAH that returned to normal by day 14. There were no significant changes in nNOS mRNA or protein at any time after SAH. There were no significant changes in iNOS mRNA whereas iNOS protein increased on days 3 and 7 (7 ± 9 and 2.7 ± 2.8-fold, respectively, p > 0.05) and significantly decreased (2.7 ± 1.1-fold, p < 0.05) on day 14. Immunohistochemistry localized eNOS to endothelium, nNOS to brain and perivascular adventitia of the middle cerebral arteries and iNOS to inflammatory cells in the subarachnoid space. These results show a correlation between decreased eNOS and increased iNOS during vasospasm, suggesting a complex role for changes in NO in vasospasm.

Gliosarcoma: an immunohistochemical study.

Gliosarcomas contain both neuro-ectodermal and mesenchymal elements. Its histogenesis has been much debated and endothelial and adventitial fibroblast origins have been suggested, as has a "histiocytic" origin following the demonstration of antiprotease activity. Eight gliosarcomas have been examined with a panel of ten monoclonal and polyclonal antibodies to investigate the origin of the sarcomatous element. Glial fibrillary acid protein expression showed a sharp distinction between gliomatous and sarcomatous tumour components. Contrary to some previous reports factor 8-related antigen and Ulex europeus agglutinin stained vascular luminal endothelium but no tumour cells. Vimentin and fibronectin expression was extensive and confined largely to sarcomatous areas. Desmin and neurofilament protein could not be demonstrated in any of the cases. Numerous cells, particularly in the sarcoma areas, expressed alpha-1-antitrypsin and -chymotrypsin. A proportion of these stained for the monocyte/macrophage marker MAC 387. Four cases focally exhibited a true storiform pattern and this and the immunohistochemical results suggest analogies with the fibrous histiocytomas. These tumours contain reactive histiocytes but are now thought to be derived from fibroblasts or from pluripotent mesenchymal cells in perivascular adventitia. This resembles the pattern exhibited in the sarcomatous component of gliosarcomas.

FAMILIAL NONHEMOLYTIC JAUNDICE: BILIRUBINOSIS AND ENCEPHALOPATHY

The unique pathological findings of a case of congenital familial hyperbilirubinemia are presented. The patient (Case 3 of Crigler and Najjar's original report), although severely jaundiced, had developed normally without evidence of neurological disease until 15½ years of age. He then developed a progressive neurological deterioration which was clinically similar to infantile kernicterus. At autopsy most of his organs showed extensive intra- and extracellular deposition of bile pigment, particularly the renal papillae, atrial endocardium, intestinal mucosa, Kupffer cells of the liver, and the perivascular adventitia. Although no pigment was found in the central nervous system, there was striking neuronal loss and gliosis of the thalamus. Moderate neuronal loss was found in the putamen, caudate nucleus, dentate nucleus, and red nuclei. No histopathological changes were found in the hippocampus or cerebral cortex. It is suggested that the patient suffered from a late onset of "kernicterus" with involvement, in this older patient, of regions of the nervous system somewhat different from those in infantile kernicterus.