Periaortic Tissue Research Articles

Inhibition of renin–angiotensin system attenuates periadventitial inflammation and reduces atherosclerotic lesion formation

Recent evidence indicates that renin–angiotensin system (RAS) plays an important role in the pathogenesis of atherosclerosis. It was reported that inhibition of RAS with angiotensin II type 1 receptor blockers (ARBs) or angiotensin converting enzyme inhibitors (ACEIs) is effective in prevention of atherosclerosis. Here, we investigated the effects of an ARB or/and an ACEI on atherosclerosis development and periadventitial inflammation in apolipoprotein E (ApoE)-deficient mice. RT-PCR revealed that major RAS components were expressed in periaortic tissue. Ang II infusion significantly increased accumulation of bone marrow derived cells into both neointima ( p < 0.05) and periaortic tissue ( p < 0.01). Male ApoE- deficient mice were treated with either vehicle, TA606A (10 mg/kg/day, ARB), imidapril (3 mg/kg/day, ACEI) or TA606A plus imidapril (TA606A 10 mg/kg/day + imidapril 3 mg/kg/day, ARB + ACEI) for 24 weeks starting at 12 weeks of age. ARB, ACEI, and ARB + ACEI significantly reduced atherosclerotic lesion formation in aorta compared with vehicle ( p < 0.05), with reduced expression of monocyte chemoattractant protein-1 in periaortic tissues ( p < 0.01). Neither blood pressure nor heart rate was changed by the treatments at these lower doses. Imidapril significantly reduced lipid deposition in atheroma and plasminogen activator inhibitor-1 expression in periadventitial tissue ( p < 0.05, respectively). Imidapril and combination therapy significantly attenuated macrophage infiltration into the atherosclerotic plaque ( p < 0.05, respectively). All treatments reduced macrophage accumulation in the periadventitial tissue 12 weeks after treatment ( p < 0.05, respectively). These results suggest that inhibition of renin–angiotensin system attenuates periadventitial inflammation and reduces atherosclerotic lesion formation.

Linfoma periaórtico tóraco-abdominal, que simula un síndrome aórtico agudo y revisión de la literatura

Systemic lymphoma that involves the aorta is called periaortic lymphoma, and may be misdiagnosed clinically or in CT sean, mimicking a thoracic aortic aneurysm, dissection, penetrating ulcer or an intramural hematoma. We report a 70 year-old woman in whom a systemic non-Hodgkin 's lymphoma ivas diagnosed after she presented with the clinical features of an acute aortic syndrome. A CT sean showed the presence of a large thoracoabdominal periaortic soft tissue mass without aneurism or dissection. Later, a biopsy of the mass ivasperformed which showed a non-Hodgkin's lymphoma. Chemotherapy with CHOP-R was effective, with complete initial resolution of the mass, developing in the follow up chylothorax, malnutrition and death.

Ormond’s disease: an unusual cause of abdominal pain

A 47-year-old male smoker with hyperlipidemia reported suffering from dull, aching, mid-abdominal pain with right groin pain for 4 months. The pain was associated with nausea, diminished appetite and a weight loss of 10 pounds (4.5 kg). He reported back pain radiating to the buttocks with bilateral calf claudication that was not relieved completely with rest. He also described significant nocturnal sweats and fever of 99–100.5°F (37.2–38.1°C). Pertinent laboratory evaluation revealed an erythrocyte sedimentation rate of 87 mm/hour and a C-reactive protein of 77.4 mg/l. Antineutrophil cytoplasmic antibodies, rheumatoid factor, and antinuclear antibody were negative. Antiphospholipid IgG antibodies were borderline elevated. The urinalysis demonstrated microscopic hematuria. Computed tomographic angiography of the abdomen revealed periaortic soft tissue thickening and enhancement of 4.5–5.0 cm, while the opacified lumen measured 1.6 cm (Panel A, arrow). Severe atheromatous disease involved the distal aorta extending into the iliac vessels. The celiac, superior mesenteric artery (SMA), and renal arteries were patent. An indium white blood cell scan revealed normal tracer uptake. The clinical findings and laboratory evaluation led to a low suspicion for malignancy or infection. Prednisone was started and 2 months later the groin pain, fever and chills were resolved with improvement of the back and abdominal pain. The inflammatory markers returned to normal. Computed tomographic angiography of the abdomen after 2 months of treatment revealed a marked reduction in the infrarenal periaortic soft tissue thickening with no aneurysmal disease (Panel B, arrow). The clinical manifestations of idiopathic retroperitoneal fibrosis or Ormond’s disease include inflammatory abdominal aortic aneurysm as well as chronic periaortitis.1 Periaortic fibrous tissue may encase adjacent structures causing obstructive complications such as deep venous thrombosis and ureteral obstruction. In the case presented, the inflammatory component predominated with rapid response to steroid therapy. Advanced atherosclerotic disease is also associated with retroperitoneal fibrosis, which was apparent in this case.2,3 Panel A Panel B

Laparoscopic Treatment of Celiac Artery Compression Syndrome: Case Series and Review of Current Treatment Modalities

IntroductionCompression of the celiac artery by the diaphragmatic crura, the median arcuate ligament, or the fibrous periaortic ganglionic tissue results in a rare constellation of symptoms known as celiac artery compression syndrome (CACS). AnatomyFirst described in 1963 by Harjola in a patient with symptoms of mesenteric ischemia, it remains an elusive diagnosis. Clinical PresentationPatients commonly present with a wide variety of symptoms resulting in multiple diagnostic tests. DiagnosisA firm diagnosis is difficult to establish, and treatment is equally challenging. These challenges are illustrated by the following case series, and evidence supporting current treatment modalities is reviewed. TreatmentWe describe a laparoscopic approach to decompression of the celiac artery facilitated by intraoperative ultrasound.

Chronic Periaortitis

Chronic Periaortitis

A Comparison of Computed Tomography, Magnetic Resonance Imaging, and Digital Subtraction Angiography Findings in the Diagnosis of Infected Aortic Aneurysm

To characterize imaging findings from computed tomography, magnetic resonance imaging, and angiogram in patients with infected aortic aneurysm. We retrospectively reviewed the records of 21 patients (men, 17; women, 4) with proven infected aortic aneurysms and compared the imaging findings (computed tomography scans, n = 21; magnetic resonance images, n = 2; and angiograms, n = 2). Aneurysms were located in the descending thoracic aorta (n = 10; 47.6%), abdominal aorta (n = 6; 28.6%), aortic arch (n = 3; 14.3%), and thoracoabdominal aorta (n = 2; 9.5%). Aneurysms were saccular in 19 (90%) and fusiform in 2 (10%). Maximal diameters were greater than 10 cm in 2 patients (10%), 5 to 10 cm in 11 (52%), and less than 5 cm in 8 (38%). Average diameters were 6.5 cm in the aortic arch, 5.3 cm in the descending thoracic aorta, and 5.1 cm in the abdominal aorta. Obvious aortic wall calcification occurred in 19 patients (90%). Other features included disrupted calcification (n = 15; 71%), prominent and irregular wall thickening (n = 17; 81%), periaortic soft tissue mass (n = 15; 71%), rim enhancement (n = 18; 86%), periaortic gas (n = 7; 33%), periaortic stranding and fluid retention (n = 14; 67%), periaortic hematoma (n = 3; 14%), adjacent bone destruction (n = 1; 5%), pleural effusion (n = 12; 57%), and associated dissecting aneurysm (n = 2; 10%). Saccular aneurysms, adjacent soft tissue masses, rim enhancement, stranding, fluid, gas, and unusual adjacent bony destruction highly suggest infected aneurysm.

Galectin-3 Gene Inactivation Reduces Atherosclerotic Lesions and Adventitial Inflammation in ApoE-Deficient Mice

This study has examined the role of galectin-3 (GaL3), a multicompartmented N-acetyllactosamine-binding chimeric lectin, on atherogenesis in the ApoE-deficient mouse model of atherosclerosis. Pathological changes consisting of atheromatous plaques, atherosclerotic microaneurysms extending into periaortic vascular channels, and adventitial and periaortic inflammatory infiltrates were assessed in an equal number (n = 36) of apolipoprotein (Apo)E-deficient mice and ApoE-GaL3 double-knockout mice. These mice were divided into three age groups, 21 to 23 weeks, 25 to 31 weeks, and 36 to 44 weeks of age. Results of this morphological analysis have shown an age-related increase in the incidence of aorta atheromatous plaques and periaortic vascular channels in ApoE-deficient mice. By contrast ApoE/GaL3 double-knockout mice did not show an increase in pathological changes with age. The 36- to 44-week group of ApoE(-/-)/GaL3(-/-) mice had a significantly lower number of atherosclerotic lesions (P < 0.004) and fewer atheromatous plaques (P < 0.008) when compared with ApoE(-/-)/GaL3+/+ mice of the same age. ApoE(-/-)/GaL3(-/-) mice had a lower number of perivascular inflammatory infiltrates and mast cells than those found in ApoE(-/-)/GaL3+/+ mice. The reduced number of perivascular mast cells may have resulted in a low level of interleukin-4 that contributed to the reduction in the morphological parameters of atherogenesis correlated with the lack of GaL3 expression. The effect of GaL3 deficiency on atherogenesis decrease could be related to its function as a multifunctional protein implicated in macrophage chemotaxis, angiogenesis, lipid loading, and inflammation.

Hypermetabolic activity in patients with active retroperitoneal fibrosis on F-18 FDG PET: report of three cases

Idiopathic retroperitoneal fibrosis is an uncommon disease characterized by periaortic inflammation with gradual fibrosis and distortion of retroperitoneal structures such as the ureter. Several earlier case reports have documented hypermetabolic retroperitoneal activity on fluorodeoxyglucose positron emission tomography (FDG PET) in patients with active disease, and a decrease in the activity following immunosuppressive therapy. We report FDG PET positive findings in three patients presenting with active retroperitoneal fibrosis. In two cases, enhancing periaortic soft tissue seen on computed tomography (CT) markedly diminished following immunosuppressive therapy. In one patient, repeat FDG PET was performed following immunosuppressive therapy, with complete resolution of the retroperitoneal FDG avidity. We suggest that FDG PET may play a useful adjunct to anatomic imaging and serum inflammatory markers in assessing the severity of inflammation in retroperitoneal fibrosis, and in assessing the likelihood of response to immunosuppressive therapy. FDG PET may also be used in follow-up to assess therapeutic response if CT findings are unclear.

Spontaneous myogenic differentiation of Flk-1-positive cells from adult pancreas and other nonmuscle tissues

At the embryonic or fetal stages, autonomously myogenic cells (AMCs), i.e., cells able to spontaneously differentiate into skeletal myotubes, have been identified from several different sites other than skeletal muscle, including the vascular compartment. However, in the adult animal, AMCs from skeletal muscle-devoid tissues have been described in only two cases. One is represented by thymic myoid cells, a restricted population of committed myogenic progenitors of unknown derivation present in the thymic medulla; the other is represented by a small subset of adipose tissue-associated cells, which we recently identified. In the present study we report, for the first time, the presence of spontaneously differentiating myogenic precursors in the pancreas and in other skeletal muscle-devoid organs such as spleen and stomach, as well as in the periaortic tissue of adult mice. Immunomagnetic selection procedures indicate that AMCs derive from Flk-1(+) progenitors. Individual clones of myogenic cells from nonmuscle organs are morphologically and functionally indistinguishable from skeletal muscle-derived primary myoblasts. Moreover, they can be induced to proliferate in vitro and are able to participate in muscle regeneration in vivo. Thus, we provide evidence that fully competent myogenic progenitors can be derived from the Flk-1(+) compartment of several adult tissues that are embryologically unrelated to skeletal muscle.

Median arcuate ligament syndrome: Open celiac artery reconstruction and ligament division after endovascular failure

Median arcuate ligament syndrome (MALS) is a rare disorder resulting from extrinsic compression and narrowing of the celiac artery, and--less often--the superior mesenteric artery, by the relatively low insertion of the ligament and/or prominent fibrous bands or ganglionic periaortic tissue of the celiac nervous plexus. We report on a young woman who after three consecutive attempts of endovascular therapy with balloon angioplasty and stenting for MALS, each followed by gross symptom recurrence and a cumulative weight loss of 10 kg, underwent open surgical division of the ligament and reconstruction of the celiac artery. Despite the initial response of MALS to endovascular therapy, the extrinsic pressure exerted on the celiac artery by the surrounding dense fibrous/ganglionic tissue resulted in slippage of the stents and/or failure of their material. These findings militate against the use of balloon angioplasty and stenting primarily in patients with MALS without prior release of the extrinsic compression on the celiac (and/or superior mesenteric) artery by dividing the surrounding median arcuate ligament and/or ganglionic tissue with open or laparoscopic surgery.

Retroperitoneal fibrosis: A rare vascular and immune entity disclosed by chronic lombalgia

Retroperitoneal fibrosis is a rare inflammatory and fibrotic process in the retroperitoneal peri-aortic tissues, associated with ureters and other abdominal organs' entrapment. Here we report an original observation of a 55-year-old patient presenting with chronic lombalgia disclosing idiopathic retroperitoneal fibrosis. After one-year follow-up, treatment with corticosteroids led to a complete clinical, biological, and radiological response. Pathogenesis and therapeutic options in idiopathic retroperitoneal fibrosis are discussed.

Emergence of haematopoietic stem cells during development

Self-renewable haematopoietic stem cells (HSCs) become segregated during development into a finite pool, from which they are mobilized upon physiological requirement. A central feature characterizing developmental haematopoiesis is that definitive organs become colonized by HSCs originating from a central source. The emission of HSCs occurs more or less continuously during a protracted period in parallel or successive sites. The most recently discovered of these sites is the placenta. The allantois, which is one of the components of the placenta, probed before it becomes vascularised, turns out to be a location where clonogenic precursors become committed. The placenta is thus a site of intrinsic haematopoiesis. Until this finding, the aorta and periaortic tissues were held to be the sites of definitive HSC commitment. The haematopoietic process in the aorta is prominent, particularly in avian embryos, and displays striking anatomical relationships between endothelial and haematopoietic cells. This made it possible to investigate the cytological and molecular relationship between the two types of cells. Somite exchanges between quail and chicken disclosed two distinct lineages, a dorsal one, purely endothelial, and a ventral one, hemangioblastic. The latter, also termed hemogenic endothelium, builds at first the whole inside lining of the aorta, and is then progressively replaced by cells of somitic origin, beginning with the aortic roof; it emits haematopoietic cells when located in the floor of the aorta and disappears. These events involve a changing molecular pattern, with expressions of transcription factor Runx1 and receptor VEGF-R2 as faithful markers of the lineage switch. Taking advantage of the stereotyped anatomical arrangement at the aortic level, which is favourable to dissect the mechanisms of HSC commitment, the analysis of developmental haematopoiesis should progress still further. To cite this article: F. Dieterlen-Lièvre, C. R. Biologies 330 (2007).

Spectrum of CT Findings in Rupture and Impending Rupture of Abdominal Aortic Aneurysms

Prompt diagnosis of rupture and impending rupture of abdominal aortic aneurysms is imperative. The computed tomographic (CT) findings of ruptured abdominal aortic aneurysms are often straightforward. Most ruptures are manifested as a retroperitoneal hematoma accompanied by an abdominal aortic aneurysm. Periaortic blood may extend into the perirenal space, the pararenal space, or both. Intraperitoneal extravasation may be an immediate or a delayed finding. Discontinuity of the aortic wall or a focal gap in otherwise continuous circumferential wall calcifications may point to the location of a rupture. There usually is a delay of several hours between the initial intramural hemorrhage and frank extravasation into the periaortic soft tissues. Contained or impending ruptures are more difficult to identify. A small amount of periaortic blood may be confused with the duodenum, perianeurysmal fibrosis, or adenopathy. Imaging features suggestive of instability or impending rupture include increased aneurysm size, a low thrombus-to-lumen ratio, and hemorrhage into a mural thrombus. A peripheral crescent-shaped area of hyperattenuation within an abdominal aortic aneurysm represents an acute intramural hemorrhage and is another CT sign of impending rupture. Draping of the posterior aspect of an aneurysmal aorta over the vertebrae is associated with a contained rupture.

Wegener Granulomatosis With Back Pain, Periaortitis, and Dural Inflammation Developing While Receiving Monthly Cyclophosphamide

A 61-year-old white man was admitted to our department because of severe back and upper abdominal pain of 1 month's duration. The patient was diagnosed with Wegener granulomatosis 10 months before the presentation based on chronic otitis media, hoarseness, and hemoptysis; positive c-ANCA; and laryngeal and lung biopsies showing multinucleated giant cells. The patient was treated with monthly injections of cyclophosphamide (1-1.5 g per month) and 80 mg prednisone daily with rapid improvement. Prednisone dose was tapered off and 1 month before the present admission, the patient developed severe low back pain. Extensive workup, including abdominal computed axial tomography scan, computed tomography angiography, magnetic resonance image of the spinal cord, and fluorodeoxyglucose-positron emission tomography (FDG-PET) scan, revealed 2 periaortic soft tissue structures seen at the level of L3 and at the level of the celiac trunk and linear meningeal thickening of the spinal cord at the level of D4-8. All these structures showed strong signal on FDG-PET scan. Treatment with methylprednisolone (1000 mg/d) for 3 consecutive days followed by 80 mg prednisone per day and 100 mg cyclophosphamide per day was started with rapid attenuation of the patient's symptoms. This case describes the clinical course of the rare complication of Wegener granulomatosis, periaortitis, and dural inflammation despite monthly cyclophosphamide and demonstrates the role of magnetic resonance imaging and FDG-PET in their diagnosis.

Periaortic lymphoma as a mimic of posttraumatic intramural hematoma

Computed tomography (CT) of an 87-year-old man who presented to the emergency department with chest pain after a motor vehicle collision demonstrated multiple broken ribs and a thoracic periaortic soft tissue mass which was high density on precontrast images and enhanced postcontrast. The scan also demonstrated a mass encircling the left ureter and masses in the axilla and pelvis. The enhancement of the periaortic lesion and the presence of the additional soft tissue masses suggested lymphoma as opposed to intramural hematoma (IMH). The diagnosis of follicular B-cell lymphoma was rapidly confirmed with fluorodeoxyglucose-positron emission tomography/CT and excisional biopsy of the axillary lymph node. While this is an atypical presentation, lymphoma and other extravascular pathology must be considered in the evaluation of a periaortic high attenuation mass seen on CT.

Intra Vascular Ultra Sound: One More Tool to Diagnose Aorto-duodenal Fistula

The incidence of aorto-enteric fistula in the first 5 years after abdominal aortic replacement ranges from 0.3 to 2%. We present a clinical case in which all conventional diagnostic tools failed to demonstrate the aorto-enteric fistula. A 73 year-old male suffering intermittent episodes of melena without signs and symptoms of infection was repeatedly admitted at our institution. All conventional diagnostic tools failed to show the bleeding source. Precise diagnosis was obtained using intra vascular ultrasound (IVUS). IVUS allowed prompt diagnosis of the aorto-duodenal fistula and opened the way to its endovascular treatment.

Autoimmune Pancreatitis Associated with Idiopathic Retroperitoneal Fibrosis: A Case Report

A 69-year-old man presented with obstructive jaundice and dark urine. Contrast-enhanced computed tomography revealed an enlarged pancreas with homogenous enhancement. Endoscopic retrograde pancreatography demonstrated short-segmental, irregular narrowing of the main pancreatic duct. The patient underwent exploratory laparotomy and needle biopsies of the pancreas, which showed marked fibrotic change with lymphocyte infiltration. These clinicopathologic findings suggested autoimmune pancreatitis. Four years later, computed tomography demonstrated marked periaortic soft tissue surrounding a calcified infrarenal abdominal aorta compatible with retroperitoneal fibrosis. We diagnosed retroperitoneal fibrosis with noncontiguous pancreatic fibrosis. This patient responded well to corticosteroid treatment. Autoimmune pancreatitis associated with idiopathic retroperitoneal fibrosis seems to be extremely rare, and to our knowledge, only a few cases have been reported.

The Effect Of Hyaluronic Acid On Vascular Surgical Adhesions

Objective: Hyaluronic acid solutions and membranes have been shown experimentally to reduce adhesions following several surgical procedures. We purposed to investigate the efficacy of a bioresorbable membrane containing hyaluronic acid in preventing experimental vascular adhesions. Methods: The abdominal aortas of twelve adult rabbits were explored, cleared from surrounding tissues and abraded following median laparotomy. In six animals, bioresorbable membrane (SeprafilmAE) was wrapped around the abdominal aorta; no similar procedure was performed in the remaining six (control) animals. Two months later, the abdominal aortas were re-explored and periaortic adhesions were scored. Results: Some clinically significant periaortic adhesions were observed at re-exploration in all the animals. The mean adhesion scores of the periaortic tissues were 2.83 ± 0.75 in animals treated with bioresorbable membrane and 3.16 ± 0.75 in the controls. The difference between the groups was not statistically significant (p>0.05). Conclusion: The bioresorbable membrane did not significantly reduce the formation of adhesions after aortic vascular surgery. The use of hyaluronic acid for preventing adhesions was not effective, except for serosal membranes.

Native UCP1 Displays Simple Competitive Kinetics between the Regulators Purine Nucleotides and Fatty Acids

Elucidation of the regulation of uncoupling protein 1 (UCP1) activity in its native environment, i.e. the inner membrane of brown-fat mitochondria, has been hampered by the presence of UCP1-independent, quantitatively unresolved effects of investigated regulators on the brown-fat mitochondria themselves. Here we have utilized the availability of UCP1-ablated mice to dissect UCP1-dependent and UCP1-independent effects of regulators. Using a complex-I-linked substrate (pyruvate), we found that UCP1 can mediate a 4-fold increase in thermogenesis when stimulated with the classical positive regulator fatty acids (oleate). After demonstrating that the fatty acids act in their free form, we found that UCP1 increased fatty acid sensitivity approximately 30-fold (as compared with the 1.5-fold increase reported earlier based on nominal fatty acid values). By identifying the UCP1-mediated fraction of the response, we could conclude that the interaction between purine nucleotides (GDP) and fatty acids (oleate) unexpectedly displayed simple competitive kinetics. In GDP-inhibited mitochondria, oleate apparently acted as an activator. However, only a model in which UCP1 is inherently active (i.e."activating" fatty acids cannot be included in the model), where GDP functions as an inhibitor with a K(m) of 0.05 mm, and where oleate functions as a competitive antagonist for the GDP effect (with a K(i) of 5 nm) can fit all of the experimental data. We conclude that, when examined in its native environment, UCP1 functions as a proton (equivalent) carrier in the absence of exogenous or endogenous fatty acids.

Intrapericardial ectopic thymic tissue

Accessory intrapericardial, periaortic ectopic thymic tissue incidentally found in 2.5-year-old girl during open heart surgery is presented and discussed in detail.