Outer Media Research Articles

In vitro digestion of curcuminoid-loaded lipid nanoparticles

Curcuminoid-loaded lipid nanoparticles were produced by melt homogenization. The used lipid matrices were medium chain triglycerides, trimyristin (TM), and tristearin. The mean particle size of the preparations was between 130 and 180 nm. The incorporated curcuminoids revealed a good stability over a period of 12 months. The curcuminoid-loaded lipid nanoparticles were intended for the oral delivery of curcuminoids. Therefore, the fate of the triglyceride matrix in simulated gastric and simulated intestinal media under the influence of pepsin and pancreatin, respectively, was assessed. The degradation of the triglycerides was monitored by the pH–stat method and with high performance thin layer chromatography in connection with spectrodensitometry to quantify the different lipid fractions. The TM nanoparticles were not degraded in simulated gastric fluid (SGF), but the decomposition of the triglyceride matrix was rapid in the intestinal media. The digestion process was faster in the simulated fed state medium compared to the simulated fasted state medium. Additionally, the stability of the incorporated drug was tested in the respective physiological media. The curcuminoids showed an overall good stability in the different test media. The release of the curcuminoids from the lipid nanoparticles was determined by fluorescence imaging techniques. A slow release of the drug was found in phosphate buffer. In contrast, a more distinct release of the curcuminoids was verifiable in SGF and in simulated intestinal fluids. Overall, it was considered that the transfer of the drug into the outer media was mainly triggered by the lipid degradation and not by drug release.

Cyclooxygenase immunohistochemical staining in the human ductus arteriosus after 24 weeks of gestational age

Cyclooxygenase inhibitors (CI) which contained risks to fetal health were one of the most effective tocolytics. In order to indirectly investigate the effects of CI in human ductus arteriosus, immunohistochemical staining for cyclooxygenase-1 (COX1) and cyclooxygenase-2 (COX2) was evaluated in post-mortem fetuses with gestational ages between 24 and 34 weeks. Neither COX1 nor COX2 staining was related to gestational age. COX1 and COX2 staining in the vessel walls were not related to each other. COX1 staining in the endothelium, inner media and outer media were positively correlated with each other (COX1 endothelium vs IM staining Spearman's rho statistic [rs] = 0.721, p = 0.001; COX1 endothelium vs OM staining [rs] = 0.634, p = 0.004; COX1 IM vs OM staining [rs] = 0.931, p = 0.001). COX2 staining of endothelium was not correlated with either IM or OM staining. In conclusion, COX2 staining in the post-mortem specimens of human ductus arteriosus between 24 and 34 weeks is weak and limited to the endothelium.

Endovascular creation of aortic dissection in a swine model with technical considerations

Creating an experimental model of a type B aortic dissection with a minimally invasive endovascular procedure in swine to help future evaluation of therapies for aortic dissection. Aortic dissection was created in 14 swine using endovascular procedures only. Under fluoroscopy, a modified 10F outer catheter with a 14 G stiffening inner metallic cannula was forced via the femoral artery into the aortic vessel wall to create an initial dissection. A .035-inch guidewire and a 4F straight catheter were advanced into the dissected space, and the dissection was extended in a retrograde direction using a technique including loop formation of the guidewire, which was placed carefully against the transmural penetration and extended as far as possible in the descending thoracic aorta up to the point where loop formation of the guidewire reached smoothly. An 8F introducer sheath was advanced with a Brockenbrough needle into the dissected space, and a proximal fenestration was created by puncturing the intima. If required, balloon dilatation was performed to enlarge the proximal and distal tears. Aortography and contrast-enhanced cone beam computed tomography (CBCT) were performed in addition to a detailed histologic evaluation of the dissected portion. Aortic dissection was successfully created in 11 of the 14 swine (78.6%). Among the 11 dissections, nine were located in the thoracoabdominal aorta and two in the abdominal aorta. The initial aortic diameter at the middle portion of the created dissection ranged from 7.4 to 16.8 mm (mean ± standard deviation, 10.9 ± 2.9), while after dissection, it ranged from 7.8 to 19.3 mm (12.9 ± 3.8 mm). The dissected length ranged from 4.4 to 17.7 cm (10.7 ± 4.6 cm). Aortography and CBCT revealed seven dissections (63.6%) with a smooth and patent false lumen. Histologic evaluation revealed that the outer one-third of the media was separated from the inner two-thirds. In the remaining four dissections (36.4%), imaging procedures revealed the formation of a rough and patent false lumen beside the true lumen, and histologic evaluation revealed greater separation of the outer media. Five animals were chronic dissection models. Three (60%) of these survived for more than 14 days without any symptoms. Moreover, completely patent true and false lumens without thrombus formation were observed in these three animals. The aortic diameter at the dissected portion tended to be dilated compared with the initial diameter. This new technique of creating an experimental aortic dissection model in swine is promising and should contribute to the development of future therapies for aortic dissection.

The implication of vasa vasorum in surgical diseases of the aorta

Vasa vasorum (VV) are microscopic vases that perfuse the vessel's wall; arteries and veins. Many recent researches support the opinion that VV have a significant role in aortic pathology. The VV, or 'the vessels of the vessels', form a network of microvessels that lie in the adventitia and penetrate the outer media of the host vessel wall. Although the importance of the VV in providing nutritional support is not well known, obstruction of blood flow through these vessels has been implicated in the pathogenesis of many cardiovascular diseases such as aortic intramural hematoma, aortic aneurysm, and acute or chronic aortic dissection. Although the proliferation of VV due to atherogenic stimuli is controversial, experimental and clinical studies strongly suggest the potential of VV in vascular proliferative disorders. It seems that the rupture of VV is implicated in intramural hematoma, which can develop in acute aortic dissection. In this review article, we would like to stress the anatomy and mainly the pathophysiology, and the implication of VV in the acute and chronic aortic pathologies.

Histomorphometric and sympathetic innervation of the human superficial temporal artery

Context:Following microvascular surgeries, stenosis and spasm of the arterial graft or the recipient vessel are serious complications which are often caused by intimal hyperplasia and perivascular nerves, respectively.Aims:The purpose of this study was to understand the characteristics of arterial wall and sympathetic innervation of the human superficial temporal artery (STA) and also, the effect of aging on STA.Methods and Materials:Fifty-two fresh human STA (frontal branch) samples were obtained from 26 cadavers (19 males and 7 females) between the ages of 19 and 83 years. Samples were divided into three age groups: G1, 19-40 years; G2, 41-60 years; G3, over 61 years. 5μm-thin sections of each sample were taken and stained with haematoxylin-eosin, Verhoff's and tyrosine hydroxylase (TH) immunostaining.Results:The well-defined internal elastic lamina (IEL) was observed in all samples of STA, whereas external elastic lamina (EEL) was not prominent in almost all cases or absent in few cases. This might be the important factor in the process of intimal and medial hyperplasia in the frontal branch of STA. Notably, intimal thickening appeared from second decade of life. Sympathetic fibres are located mainly in tunica adventitia and outer media. Mean adventitial and sympathetic areas were found to be 0.080 and 0.010mm2, respectively.Statistical analysis used:One-way ANOVA followed by Tukey HSD post hoc test by using the SPSS 11.5 software.Conclusions:STA is prone to age related pathological changes. Sympathetic index may be used for analysis of sympathetic fibre-related problems (vasospasm, migraine) of the STA.

Histomorphometric and sympathetic innervation of the human superficial temporal artery

ABSTRACT Context: Following microvascular surgeries, stenosis and spasm of the arterial graft or the recipient vessel are serious complications which are often caused by intimal hyperplasia and perivascular nerves, respectively. Aims: The purpose of this study was to understand the characteristics of arterial wall and sympathetic innervation of the human superficial temporal artery (STA) and also, the effect of aging on STA. Methods and Materials: Fifty-two fresh human STA (frontal branch) samples were obtained from 26 cadavers (19 males and 7 females) between the ages of 19 and 83 years. Samples were divided into three age groups: G1, 19-40 years; G2, 41-60 years; G3, over 61 years. 5μm-thin sections of each sample were taken and stained with haematoxylin-eosin, Verhoff's and tyrosine hydroxylase (TH) immunostaining. Results: The well-defined internal elastic lamina (IEL) was observed in all samples of STA, whereas external elastic lamina (EEL) was not prominent in almost all cases or absent in few cases. This might be the important factor in the process of intimal and medial hyperplasia in the frontal branch of STA. Notably, intimal thickening appeared from second decade of life. Sympathetic fibres are located mainly in tunica adventitia and outer media. Mean adventitial and sympathetic areas were found to be 0.080 and 0.010mm2, respectively. Statistical analysis used: One-way ANOVA followed by Tukey HSD post hoc test by using the SPSS 11.5 software. Conclusions: STA is prone to age related pathological changes. Sympathetic index may be used for analysis of sympathetic fibre-related problems (vasospasm, migraine) of the STA.

Histomorphometric and sympathetic innervation of the human renal artery: A cadaveric study

Background and Aim:Renal artery stenosis (RAS) and acute renal failure may be due to the intimal hyperplasia and sympathetic fibers of the renal artery (RA), respectively. The purpose of this study was to characterize arterial wall and sympathetic innervation of the human RA.Materials and Methods:Fifty-two fresh human RA samples (proximal part) were collected from 26 cadavers (19 males and 7 females), between the ages of 19 and 83 years, during autopsy. Samples were divided into three age groups: Group 1, 19-40 years; Group 2, 41-60 years; Group 3, over 61 years. 5-μm thick sections of each sample were taken and stained with hematoxylin-eosin and Verhoeff-Van Gieson. Five out of 52 samples were processed for tyrosine hydroxylase (TH) immunostaining.Results:Our histological studies revealed that tunica media of RA showed smooth muscle cells and fine irregularly arranged elastic fibers. Intimal hyperplasia was the most common finding. The present study showed that thickness of tunica intima and media were found to increase with age. Sympathetic nerves were present in the tunica adventitia and outer media of the RA. The mean adventitial and sympathetic nerve fiber areas were found to be 0.595 and 0.071 mm2, respectively. Sympathetic index (SI) to RA was calculated by dividing the sympathetic fiber area by the adventitial area of the RA. SI of RA was found to be 0.140.Conclusion:We conclude that RA showed the structure of musculo-elastic artery. SI may be used for the analysis of sympathetic fiber related problems of the human RA or kidneys.

Dopamine receptor subtypes in the human coronary vessels of healthy subjects

Objective: Dopamine D1–D5 receptors subtypes were studied in human coronary vessels of healthy subjects to assess their localization and their expression.Methods: Samples of intraparenchymal and extraparenchymal branches of human coronary arteries and veins were harvested from four normal native hearts explanted from four young brain dead heart donors in case of orthoptic transplant, not carried out for technical reasons. In all the samples morphological, biochemical, immunochemical, and morphometrical studies were performed including quantitative analysis of images and evaluation of data.Results: Microanatomical section showed healthy coronary vessels, which expressed all dopamine receptors (from D1 to D5) with a different pattern of distribution between the different layers, in the intra and in the extraparenchymal branches.D1 and D5 (with a prevalence D1 over D5) were distributed in the adventitia and to a lesser extent in the outer media but they were absent in arterioles, capillaries and venules. Endothelial and the middle layer showed D2, D3 and D4 receptors, with a greater expression of D2. Immunoblot analysis of dopamine monoclonal antibodies and dopamine receptors showed a different migration band for each receptor: D1 (45 KDa); D2 (43 KDa); D3 (42 kDa); D4 (40–42 KDa); D5 (38–40 KDa)Conclusion: These findings demonstrate the presence of all dopamine receptor subtypes in the wall of human coronary vessels of healthy subjects. Dopamine D1 and D2 receptor subtypes are the most expressed, suggesting their prominent role in the coronary vasoactivity.

Segmental Arterial Mediolysis

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy, which is characterized by dissecting aneurysms resulting from lysis of the outer media of the arterial wall. The most common presentation is abdominal pain and hemorrhage in the elderly. Computed tomography (CT) and angiography imaging findings overlap with various vasculitides and include segmental changes of aneurysm and stenosis. A key distinguishing feature is the presence of dissections, the principle morphologic expression of SAM. Differentiation and exclusion of an inflammatory arteritis is crucial in appropriate management, as immunosuppressants generally used for treatment of vasculitis may be ineffective or even worsen the vasculopathy. Although the disease can be self-limiting without treatment or with conservative medical therapy, the acute process carries a 50% mortality rate and may necessitate urgent surgical and/or endovascular therapy. Prompt recognition and diagnosis are therefore of utmost importance in appropriate management of this rare entity.

Micro-FTIR imaging spectroscopy of calcified atheromatous carotid plaques. Part IV

Micro-imaging infrared spectroscopy has been performed on atheromatous plaques in order to localize and characterize substances responsible for the cytotoxic effects that prevent macrophages clearance of lipidic and calcified materials. In plaques with different graded atherosclerotic lesions, infrared determinations allowed to visualize gruel and ceroid toxic components and variously calcified zones. Compare correlations let to visualize the progression of the lesion on going from the lumen to the outer media of the plaque.

Matrix metalloproteinase-2 and -9 are associated with high stresses predicted using a nonlinear heterogeneous model of arteries.

Arteries adapt to their mechanical environment by undergoing remodeling of the structural scaffold via the action of matrix metalloproteinases (MMPs). Cell culture studies have shown that stretching vascular smooth muscle cells (VSMCs) positively correlates to the production of MMP-2 and -9. In tissue level studies, the expressions and activations of MMP-2 and -9 are generally higher in the outer media. However, homogeneous mechanical models of arteries predict lower stress and strain in the outer media, which appear inconsistent with experimental findings. The effects of heterogeneity may be important to our understanding of VSMC function since arteries exhibit structural heterogeneity across the wall. We hypothesized that local stresses, computed using a heterogeneous mechanical model of arteries, positively correlate to the levels of MMP-2 and -9 in situ. We developed a model of the arterial wall accounting for nonlinearity, residual strain, anisotropy, and structural heterogeneity. The distributions of elastin and collagen fibers in situ, measured in the media of porcine carotid arteries, showed significant nonuniformities. Anisotropy was represented by the direction of collagen fibers measured by the helical angle of VSMC nuclei. The points at which the collagen fibers became load bearing were computed, assuming a uniform fiber strain and orientation under physiological loading conditions, an assumption motivated by morphological measurements. The distributions of circumferential stresses, computed using both heterogeneous and homogeneous models, were correlated to the distributions of expressions and activations of MMP-2 and -9 in porcine common carotid arteries incubated in an ex vivo perfusion organ culture system under physiological conditions for 48 h. While strains computed using incompressibility were identical in both models, the heterogeneous model, unlike the homogeneous model, predicted higher circumferential stresses in the outer layer correlated to the expressions and activations of MMP-2 and -9. This implies that localized remodeling occurs in the areas of high stress and agrees with results from cell culture studies. The results support the role of mechanical stress in vascular remodeling and the importance of structural heterogeneity in understanding mechanobiological responses.

An Osmoregulatory Basis for Shape Oscillations in Regenerating Hydra

The freshwater polyp Hydra has considerable regeneration capabilities. A small fragment of tissue excised from an adult animal is sufficient to regenerate an entire Hydra in the course of a few days. During the initial stages of the regeneration process, the tissue forms a hollow sphere. Then the sphere exhibits shape oscillations in the form of repeated cycles of swelling and collapse. We propose a biophysical model for the swelling mechanism. Our model takes the osmotic pressure difference between Hydra's inner and outer media and the elastic forces of the Hydra shell into account. We validate the model by a comprehensive experimental study including variations in initial medium concentrations, Hydra sphere sizes and temperatures. Numerical simulations of the model provide values for the swelling rates that are in agreement with the ones measured experimentally. Based on our results we argue that the shape oscillations are a consequence of Hydra's osmoregulation.

Adventitial Mast Cells Contribute to Pathogenesis in the Progression of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is histologically characterized by medial degeneration and various degrees of chronic adventitial inflammation, although the mechanisms for progression of aneurysm are poorly understood. In the present study, we carried out histological study of AAA tissues of patients, and interventional animal and cell culture experiments to investigate a role of mast cells in the pathogenesis of AAA. The number of mast cells was found to increase in the outer media or adventitia of human AAA, showing a positive correlation between the cell number and the AAA diameter. Aneurysmal dilatation of the aorta was seen in the control (+/+) rats following periaortic application of calcium chloride (CaCl2) treatment but not in the mast cell-deficient mutant Ws/Ws rats. The AAA formation was accompanied by accumulation of mast cells, T lymphocytes and by activated matrix metalloproteinase 9, reduced elastin levels and augmented angiogenesis in the aortic tissue, but these changes were much less in the Ws/Ws rats than in the controls. Similarly, mast cells were accumulated and activated at the adventitia of aneurysmal aorta in the apolipoprotein E-deficient mice. The pharmacological intervention with the tranilast, an inhibitor of mast cell degranulation, attenuated AAA development in these rodent models. In the cell culture experiment, a mast cell directly augmented matrix metalloproteinase 9 activity produced by the monocyte/macrophage. Collectively, these data suggest that adventitial mast cells play a critical role in the progression of AAA.

Abstract 1164: Mast Cells Contribute to Pathogenesis in the Progression of Abdominal Aortic Aneuyrsm

Abdominal aortic aneurysm (AAA) is histologically characterized by medial degeneration and various degrees of chronic adventitial inflammation, while the mechanisms for progression of aneurysm are poorly understood. In the present study, we carried out histological study of AAA tissues of patients (75±1 years, Mean±SEM), and interventional animal and cell culture experiments to investigate the role of mast cells in the pathogenesis of AAA. The number of mast cells determined by positive staining for tryptase, a major neutral protease of human mast cell secretory granules, was found to increase in the outer media or adventitia of human AAA, compared to those in the control aorta (2.1±1.1/mm 2 (n=57) vs. 0.6±0.4/mm 2 (n=22), p<0.01), showing a positive correlation (r=0.442, p<0.01) between the cell number and the AAA diameter. Western blot demonstrated that the protein expressions of tryptase, stem cell factor (a ligand for c-kit) and the phosphorylation of c-kit were significantly (p<0.01) increased in the AAA tissues, compared with the control aorta. In the animal experiments, diameter of abdominal aorta of the control (+/+) rats was increased up to 55% at 14 days following peri-aortic application of 0.4 mol/L calcium chloride, but only a 13% increase in the mast cell-deficient mutant Ws/Ws rats. The AAA formation was accompanied by accumulation of mast cells, T-lymphocytes, interferon-γ positive cells and by activated matrix metalloproteinases (MMP)-2 and -9, reduced elastin levels and augmented angiogenesis in the aortic tissue, but these changes were much less in the Ws/Ws rats than in the control (+/+) rats. The pharmacological intervention with the mast cell stabilizer tranilast (400 mg/kg/day) for 14 days significantly (p<0.01) attenuated the AAA development in the control (+/+) rats. Co-culturing the mast cell line HMC-1 with the monocyte/macrophage cell line U937 significantly (p<0.01) augmented MMP-9 activity. Furthermore, 100 and 300 μmol/L of tranilast significantly (p<0.01) decreased MMP-9 activity in those cells. Collectively, these data suggest that mast cells may play important roles in the progression of AAA.

Segmental Arterial Mediolysis With Accompanying Venous Angiopathy: A Clinical Pathologic Review, Report of 3 New Cases, and Comments on the Role of Endothelin-1 in Its Pathogenesis

The authors review 20 cases of segmental arterial mediolysis (SAM) including 3 newly reported cases. SAM developed in areas of vascular distention in 2 of the latter cases: 1 in utero in the heart of a recipient of a twin transfusion syndrome and the other in the jejunum secondary to partial venous obstruction. In the third case, it occurred in a patient with Raynaud disease. Characterizing SAM are injurious and reparative lesions that occur in the media and/or at the adventitial medial junction. Four distinctive alterations are recognized: (1) mediolysis, (2) a tearing separation of the outer media from adventitia, (3) arterial gaps, and (4) a florid reparative response that replaces zones of mediolysis and fills areas of medial adventitial separation. The repair can transform SAM into lesions indistinguishable from common types of fibromuscular dysplasia (FMD.) A venous angiopathy involving large and medium-sized veins accompanies SAM. It features medial muscle vacuolar change with lysis leading to apparent separation of residual muscle bundles. Immunostaining shows endothelin-1 (ET-1) decorating adventitial capillaries in SAM and neighboring arteries, in capillaries of adjoining tissues, and outlining smooth muscle cell membranes in adjacent veins including those of the venous angiopathy. The significance of these changes is uncertain. Vasospasm is believed to cause SAM, but ET-1 is not the direct pressor agent responsible for this condition. The reason(s) for synthesis and release of ET-1 in SAM are still hypothetical, but local perturbations in vascular tone may be an important factor. ET-1 may be indirectly play a role in SAM by cross-talking and potentiating the activities of other vasoconstrictors such as norepinephrine and by orchestrating its reparative phase.

Activated myeloid dendritic cells accumulate and co-localize with CD3 + T cells in coronary artery lesions in patients with Kawasaki disease

Emerging evidence implicating the participation of dendritic cells (DCs) and T cells in various vascular inflammatory diseases such as giant cell arteritis, Takayasu's arteritis, and atherosclerosis led us to hypothesize that they might also participate in the pathogenesis of coronary arteritis in Kawasaki disease (KD). Coronary artery specimens from 4 patients with KD and 6 control patients were obtained. Immunohistochemical and computer-assisted histomorphometric analyses were performed to detect all myeloid DCs (S-100 +, fascin +), all plasmacytoid DCs (CD123 +) as well as specific DC subsets (mature myeloid DCs [CD83 +], myeloid [BDCA-1 +] and plasmacytoid DC precursors [BDCA-2 +]), T cells (CD3 +), and all antigen-presenting cells (HLA-DR +). Co-localization of DCs with T cells was assessed using double immunostaining. Significantly more myeloid DCs at a precursor, immature or mature stage were found in coronary lesions of KD patients than in controls. Myeloid DC precursors were distributed equally in the intima and adventitia. Mature myeloid DCs were particularly abundant in the adventitia. There was a significant correlation between mature DCs and HLA-DR expression. Double immunostaining demonstrated frequent contacts between myeloid DCs and T cells in the outer media and adventitia. Plasmacytoid DC precursors were rarely found in the adventitia. In conclusion, coronary artery lesions of KD patients contain increased numbers of mature myeloid DCs with high HLA-DR expression and frequent T cell contacts detected immunohistochemically. This suggests that mature arterial myeloid DCs might be activating T cells in situ and may be a significant factor in the pathogenesis of coronary arteritis in KD.

Ascending aorta dilatation in aortic valve disease: morphological analysis of medial changes

We investigated whether and how the severity of medial degeneration lesions varies along the circumference of the dilated intrapericardial aorta. Two groups of aortic wall specimens, respectively harvested in the convexity and concavity of ascending aorta in 72 patients undergoing surgery for dilatation of the intrapericardial aorta associated with aortic valve disease, were separately sent for pathology, morphometry, and ultrastructural examination. Cystic medial necrosis, fibrosis, and elastic fiber fragmentation were classified into three degrees of severity; their mean degree and morphometric findings in the convexity and in the concavity specimens were compared by paired t-test. Correlation between echocardiographic degree of aortic dilatation and severity of medial degeneration was assessed separately for each of the two groups of specimens. Morphologically, medial degeneration was found in all cases; a higher mean degree was found in the convexity group (2.39 +/- 0.58 vs 1.44 +/- 0.65 in the concavity group; P < 0.001). At morphometry normal smooth muscle cells in the convexity specimens were significantly reduced (P = 0.007); the length (P = 0.012) and number (P = 0.009) of elastic fibers reduced and increased, respectively. Moreover, in the convexity specimens a significantly smaller amount of smooth muscle cells and an increase of immunohistochemical labeling of apoptosis-associated proteins in the subintimal layer of the media was noticed. Correlation between aortic ratio and medial degeneration degree was significant in the convexity group (P < 0.001), but not in the concavity group (P = 0.249). Scanning electron microscopy analysis confirmed morphological results and allowed us to better distinguish the early pathological cavities from the microvessels, which were in the outer media in normal aorta and ubiquitous in aortitis or atherosclerosis. Electron transmission microscopy analysis showed changes in the extracellular matrix and smooth muscle cells, and these changes increased from the intima to the adventitial layer of the media. In dilated intrapericardial aorta, medial degeneration changes and expression of apoptosis-associated proteins are more marked in the ascending aorta convexity, likely due to hemodynamic stress asymmetry. Ultrastructural findings allow us to distinguish the early medial changes not yet evident on light microscopy.

Type A aortic dissection associated with Dietzia maris

Aortitis is a rare cause of aortic dissection. We report the unusual presentation of a 77-year-old male patient who underwent emergency surgery for an aortic dissection type A. A purulent pericardial fluid and inflammatory aorta were found after chest opening. Several samples were sent for analysis. The ascending aorta presented a mild dilatation with a large haematoma infiltrating the aortic root. The distal part of the ascending aorta seemed unaffected. The aortic rupture was found one centimetre above the non-coronary cusp. Aortic wall tissues were extremely fragile and with an inflammatory aspect. The patient died in the theatre room. In the histological study one out of three fragments of ascending aorta displayed longitudinal splitting of the outer media, with blood extravasation in the adventitial layer. In this level, the presence of a detritus material that reminded of bacterial colonies was noteworthy, together with abundant fibrinous exudates. In the laboratory a new specimen, Dietzia maris, was found in the pericardial liquid and in the aortic wall. We believe that this is the first reported finding of Dietzia maris in a patient with aortic disease.

Adrenomedullin in mast cells of abdominal aortic aneurysm

Produced by vascular walls, adrenomedullin (AM) exerts antifibrotic actions in the process of cardiovascular remodeling. The purpose of this study was to examine the pathophysiological role of AM in the development of human abdominal aortic aneurysm (AAA). Immunohistochemical analyses revealed that vascular smooth muscle cells in the media were positive for AM in the early stage of atherosclerotic aorta. Intense immunoreactivity was observed in mast cells of the outer media and adventitia of AAA, and the number of mast cells was greater (p < 0.01) in AAA than in atherosclerotic aorta without any aneurysmal change. To determine the role of AM in mast cells, we examined cultured human mast cell leukemia line-1 (HMC-1) and fibroblasts isolated from AAA patients. Cultured HMC-1 cells were found to express preproAM gene and release AM peptide into the cultured media. When assessed by collagenase-sensitive [3H]proline incorporation and procollagen type I C-peptide secretion, collagen synthesis in co-culture of HMC-1 and the fibroblasts was reduced by 10(-6) mol/L synthetic AM, while conversely, it increased following blockade of the action of endogenous AM with 10 microg/mL anti-AM monoclonal antibody. The present study suggests an anti-fibrotic role for AM released from mast cells, providing new insight into the biological actions of mast cell-derived AM in the development of AAA.

Force Generated by Pulmonary Arterial Smooth Muscle Cells: Spatially Distinct Cell Phenotypes from Normal and Hypertensive Arteries

Porcine pulmonary arterial smooth muscle cells (smcs) from inner and outer medial layers have distinct structural phenotypes in both normal and hypertensive pulmonary arteries. We hypothesised that force generated by smcs of the inner and outer media would differ and increase in pulmonary hypertension. Smcs were cultured from the inner (I) 25% and outer (O) 75% of the pulmonary artery wall of 4 normal 14 day old piglets (N) and 4 animals exposed to chronic hypobaric hypoxia from 3 to 14 days (H). The cytoskeletal structure of each cell isolate was studied by immunofluorescence. The basal force/time profile and response to U46619 (thromboxane mimetic) and sodium nitroprusside (SNP) were measured using a Culture Force Monitor. Smcs from all 4 sites expressed smooth muscle actin specific actin and myosin isoforms. Hsmc had shorter actin stress fibres and were less well aligned than Nsmc. HOsmcs had more cell substrate adhesions than other isolates. In a 3D collagen matrix all cell types elongated parallel to the axis of strain. Normal Osmcs exerted a greater force then the NIsmcs (528±49.6 v 349±35 dynes, p<0.05). Rapid relaxation to SNP and increase in tension to U46619 was found in both I and O smcs. In smcs from hypertensive vessels Osmcs showed a striking reduction in contraction compared with NOsmcs (177±43dynes, p<0.05) and a slow rate of force development (p<0.05). Maximum force and rate of force development by HIsmcs were normal. HOsmcs had a stable, abnormal structural phenotype that was unexpectedly associated with decreased not increased force generation. Supported by the British Heart Foundation