Hyperplasia Of Vessels Research Articles

Angiolymphoid Hyperplasia With Eosinophilia (Epithelioid Hemangioma) of the Lung A Clinicopathologic and Immunohistochemical Study ofTwo Cases

Two cases of primary angiolymphoid hyperplasia with eosinophilia (epithelioid hemangioma) (ALHE/EH) of the lung are described. Both patients are white, a 60-year-old man and a 27-year-old woman. One patient had a long-standing history of asthma, and the other had symptomatology related to the pulmonary mass. Wedge resections were performed in both cases, and both lesions shared similar histopathologic changes, mainly the presence of a tumor mass with a marked presence of eosinophils in the background, lymphoid hyperplasia, and marked proliferations of small-caliber vessels. Immunohistochemical studies using leukocyte common antigen, L-26, and UCHL-1 nicely stained the lymphoid component of the lesion, and CD31 clearly outlined the vascular component of the process. Clinical follow-up demonstrated that the woman died of status asthmaticus, and the man was alive and well 1 year after surgical resection of the lesion. Both cases highlight the ubiquitous distribution of ALHE/EH and underscore the importance of keeping these lesions in the differential diagnosis of vascular and lymphoid lesions of the lung.

Synovitis in a murine model of human factor VIII deficiency

Recurrent joint bleeding is the most common musculoskeletal manifestation of haemophilia and leads to a target joint and synovitis. The pathobiology of haemophilic synovitis (HS) is not well understood. Here the histopathological changes that occur following haemarthrosis were examined in an animal model for human HS. After two haemarthrosis, there was soft tissue and joint swelling and histological changes of acute synovitis included infiltration of the sub-synovial layer by mononuclear cells and neutrophils, thickening of the synovial membrane with villus formation, and hyperplasia of blood vessels. Subacute changes were evident after three haemarthrosis; muscle atrophy was present and an intense mononuclear cell infiltrate filled the sub-synovial space. There was destruction of articular surfaces and loss of cartilage. Seventeen months after three haemarthrosis, chronic joint changes included gross deformity and loss of congruence due to dense fibrotic tissue filling the joint space. The mononuclear inflammatory cell infiltrate and thickened synovial membrane persisted. Pits and erosions of articular surfaces and sub-chondral cysts were present. There was fibro-cartilage and new bone formation. This model of human HS should be useful to fully evaluate the biochemical and molecular changes that occur following joint bleeding and to test novel therapeutics to prevent HS.

PDZ interaction site in ephrinB2 is required for the remodeling of lymphatic vasculature

The transmembrane ligand ephrinB2 and its cognate Eph receptor tyrosine kinases are important regulators of embryonic blood vascular morphogenesis. However, the molecular mechanisms required for ephrinB2 transduced cellular signaling in vivo have not been characterized. To address this question, we generated two sets of knock-in mice: ephrinB2DeltaV mice expressed ephrinB2 lacking the C-terminal PDZ interaction site, and ephrinB2(5F) mice expressed ephrinB2 in which the five conserved tyrosine residues were replaced by phenylalanine to disrupt phosphotyrosine-dependent signaling events. Our analysis revealed that the homozygous mutant mice survived the requirement of ephrinB2 in embryonic blood vascular remodeling. However, ephrinB2DeltaV/DeltaV mice exhibited major lymphatic defects, including a failure to remodel their primary lymphatic capillary plexus into a hierarchical vessel network, hyperplasia, and lack of luminal valve formation. Unexpectedly, ephrinB2(5F/5F) mice displayed only a mild lymphatic phenotype. Our studies define ephrinB2 as an essential regulator of lymphatic development and indicate that interactions with PDZ domain effectors are required to mediate its functions.

Pathogenesis of persistent lymphatic vessel hyperplasia in chronic airway inflammation

Pathogenesis of persistent lymphatic vessel hyperplasia in chronic airway inflammation

Pathogenesis of persistent lymphatic vessel hyperplasia in chronic airway inflammation

Edema occurs in asthma and other inflammatory diseases when the rate of plasma leakage from blood vessels exceeds the drainage through lymphatic vessels and other routes. It is unclear to what extent lymphatic vessels grow to compensate for increased leakage during inflammation and what drives the lymphangiogenesis that does occur. We addressed these issues in mouse models of (a) chronic respiratory tract infection with Mycoplasma pulmonis and (b) adenoviral transduction of airway epithelium with VEGF family growth factors. Blood vessel remodeling and lymphangiogenesis were both robust in infected airways. Inhibition of VEGFR-3 signaling completely prevented the growth of lymphatic vessels but not blood vessels. Lack of lymphatic growth exaggerated mucosal edema and reduced the hypertrophy of draining lymph nodes. Airway dendritic cells, macrophages, neutrophils, and epithelial cells expressed the VEGFR-3 ligands VEGF-C or VEGF-D. Adenoviral delivery of either VEGF-C or VEGF-D evoked lymphangiogenesis without angiogenesis, whereas adenoviral VEGF had the opposite effect. After antibiotic treatment of the infection, inflammation and remodeling of blood vessels quickly subsided, but lymphatic vessels persisted. Together, these findings suggest that when lymphangiogenesis is impaired, airway inflammation may lead to bronchial lymphedema and exaggerated airflow obstruction. Correction of defective lymphangiogenesis may benefit the treatment of asthma and other inflammatory airway diseases.

Synchrotron refractive-index microradiography of human liver cancer tissue

Three human liver tissue samples (~5 mm × 40 mm × 20 mm) were excised from a cancer patient's liver during surgery. The microradiology analysis was performed with a non-standard approach on a synchrotron. High-resolution refractive-index edge-enhanced microradio- graphs that cover a larger volume of the liver tissue sample were obtained. The cancer tissue and normal tissue could be clearly identified and distinguished based on their different textures. Furthermore, new blood vessel hyperplasia was found near the cancer area. Blood vessels with a diameter smaller than 20 μm could be identified. These findings were fully consistent with the histopathological examination of the same area. Microradiographs of the newly formed blood vessels at different angles were also obtained. This result shows that it is possible to further develop this approach into a technique of microradiographic imaging for clinic diagnosis of liver cancer at the early stage.

Role of Parathyroid Hormone–Related Protein in the Regulation of Stretch-Induced Renal Vascular Smooth Muscle Cell Proliferation

In vivo, vascular smooth muscle cells (VSMC) are continuously exposed to mechanical cyclic stretch as a result of the pulsatile blood flow from the cardiac contractile cycle. Stretch is altered in pathologic conditions and contributes to vascular remodeling by modulating VSMC proliferation and death. Parathyroid hormone-related protein (PTHrP) is a locally produced poly-protein that regulates cell growth. It was shown previously that PTHrP inhibits VSMC proliferation through the auto/paracrine pathway by interacting with its receptor, the PTH1R, but stimulates VSMC proliferation through the intracrine pathway by translocating into the nucleus. In the current study, VSMC that were isolated from both resistance and compliance vessels were used to study the role of PTHrP in VSMC proliferation under experimental stretch. It is shown that PTHrP gene expression is upregulated by stretch and that PTHrP opposes the inhibitory effect induced by stretch on VSMC proliferation through the intracrine pathway. In addition, it is demonstrated that PTHrP expression is controlled at the post-transcriptional level by stretch. Taken together, these results strongly suggest that PTHrP plays a critical role in the modulation of VSMC proliferation in response to stretch. Thus, in conditions in which stretch is increased, such as in hypertension or in restenosis after angioplasty, PTHrP may contribute to vessel hyperplasia.

Clinicopathological Correlations in Chronic Sickle Cell Lung Disease.

Chronic lung injury is a major cause of morbidity and mortality in sickle cell disease. Although this pulmonary injury appears to be progressive and the etiology is multifactorial, the pathogenesis is incompletely understood. Study of the histopathologic changes can be useful as evidence of the underlying pathophysiology, especially if correlated with the clinical stage of the disease.HYPOTHESIS: The histopathology of the lung in sickle cell disease varies with the clinical stage of chronic lung disease.METHODS: Medical records and autopsy reports from 324 archived autopsies of homozygous sickle cell disease were reviewed and each case was assigned a clinical severity score that ranged from 0 (no pulmonary dysfunction) to 3 (severe pulmonary dysfunction). Histologic sections from these cases were then studied in a masked manner and findings were subjectively graded on a scale of 0 (absent) to 4+ (severe). The histopathologic findings were then correlated with the clinical stage of the lung disease, using Pearson's correlation coefficients and coefficient of determinations.RESULTS: The frequency of some histopathologic findings showed a positive correlation with the increasing severity of the clinical stage of the disease, including age (r = 0.92; R2 = 0.85), vascular intimal hyperplasia (r = 0.74; R2 = 0.55), vascular medial hyperplasia (r = 0.87; R2 = 0.76), dilation of capillary plexi (r = 0.98; R2 = 0.96) and interstitial fibrosis (r = 0.78; R2 = 0.61). Scoring of the severity of the histopathologic findings suggested a pattern of progression of the morphologic injury. The earliest evidence of injury seen during infancy consisted of focal disruption of alveolar septae with hemorrhages and interstitial fibrosis (1+). These findings were more pronounced during childhood (2+) when asymptomatic restrictive defects were reported, but capillary diffusion capacity remained normal. During adolescence, these findings were well defined (3+) along with increased tortuosity of capillaries, dilation of capillary plexi and intimal hyperplasia of medium-size vessels. In adulthood, these findings were most pronounced (4+) and were accompanied by episodic dyspnea. Obliterative vasculopathy was seen almost exclusively in cases with clinical pulmonary hypertension. At end stage there appeared to be less intra-alveolar hemorrhage and edema.DISCUSSION: These findings strongly suggest that the earliest evidence of chronic sickle lung disease is injury to capillaries and to pre- and post-capillary vessels. This early injury appears to be followed by increased tortuosity of capillaries, dilation of collateral vessels and then changes in larger arterial vessels. Interstitial fibrosis was seen in cases with restrictive defects. Increased capillary surface area secondary to tortuosity of capillaries probably accounts for the clinical evidence of normal diffusion capacity. These findings support the clinical evidence that sickle cell chronic lung disease is progressive. Furthermoore, this study strongly suggests that sickle chronic lung disease follows a pattern of injury and remains asymptomatic until the pulmonary architecture has undergone considerable remodeling. These findings help explain the stealthy way in which sickle cell disease steals the pulmonary reserve.

Syenergistic effect of 15-deoxyspergualin with costimulation blockade on alloimmune response

Introduction A virally induced alloreactive memory seems to represent a potent barrier to tolerance induction but the combination of 15-deoxyspergualin (DSG), an inhibitor of NFkB translocation, with costimulation blockade (CB)-based chimerism as an induction regimen can overcome a preformed anti-donor memory response. In this study, we investigate the ability of DSG with CB to inhibit a naïve alloimmune responses. Methods A BALB/c (H-2 d) skin or heart was transplanted into a C57BL/6 (H-2 b) recipient treated with anti-CD154 mAb (MR1; 500 mcg/d on days 0, 2, 4, 6) alone, DSG (5 mg/kg/d, days 0 to 7) alone, or both agents. Proliferation of alloreactive T cells after each treatment was also examined using a graft-versus-host disease (GvHD) model using the fluorescent dye CFSE. Results Treatment with DSG alone induced prolonged survival of the cardiac allografts (median survival time [MST]: 97.5 days). MR1 alone induced indefinite survival of cardiac allografts, although at 150 days after transplantation, the histology showed changes characteristic of chronic rejection, including interstitial fibrosis, infiltration of mononuclear cells, and intimal hyperplasia in coronary vessels. Combined treatment with DSG and MR1 induced donor-specific unresponsiveness in all recipients, graft histology showed only minimal infiltration. Treatment with DSG and MR1 also significantly prolonged the survival of skin allografts (MST: 31 days) compared with that of DSG or MR1 alone (MST: 17 and 14 days, respectively). In the GvHD model assessed with CFSE, the combined treatment was the more effective to suppress proliferation of alloreactive T cells while DSG alone inhibited proliferation more than MR1 alone. Conclusion DSG potentiates anti-CD154 therapy to suppress the alloimmune response.

Tissue factor pathway inhibitor in thrombosis and beyond.

Tissue factor (TF) plays a crucial role in the pathogenesis of thrombotic, vascular, and inflammatory disorders, and thus, the inhibition of this membrane protein provides a unique therapeutic approach for prophylaxis and/or treatment of various diseases. In recent years, tissue-factor pathway inhibitor (TFPI), the only endogenous inhibitor of the TF/FVIIa complex, has been characterized biochemically and pharmacologically. Studies in patients have demonstrated that both TF and TFPI may be indicators for the course and the outcome of cardiovascular and other diseases. Based on experimental and clinical data, TFPI may become an important drug for several clinical indications. TFPI is expected to inhibit the development of postinjury intimal hyperplasia and thrombotic occlusion in atherosclerotic vessels, and to be effective in acute coronary syndromes (ACS) such as unstable angina (UA) and myocardial infarction (MI). Of special interest is the inhibition of TF-mediated processes in sepsis and disseminated intravascular coagulation, which are associated with the activation of various inflammatory pathways as well as the coagulation system. A phase II trial of the efficacy of TFPI in patients with severe sepsis showed a mortality reduction in TFPI- compared to placebo-treated patients and an improvement of organ dysfunctions. TFPI can be administered exogenously in high doses to suppress TF-mediated effects, or high amounts of TFPI can be released from intravascular stores by other drugs such as heparin and low molecular weight heparins (LMWHs). In this way, high concentrations of the inhibitor are provided at sites of tissue damage and ongoing thrombosis. At present clinical studies with TFPI are rather limited, and the clinical potential of the drug cannot be evaluated properly. However, TFPI and its variants are expected to undergo further development and to find indications in various clinical states.

Tissue factor pathway inhibitor in thrombosis and beyond: role of heparin

Tissue factor (TF) plays a crucial role in the pathogenesis of thrombosis, angiogenesis and inflammatory disorders, and the inhibition of this membrane protein thus provides a unique therapeutic approach for the prophylaxis and/or treatment of various diseases. In the past few years, TF pathway inhibitor (TRPI), the only endogenous inhibitor of the TF/FVIIa complex, has been characterized biochemically and pharmacologically. Studies in patients have demonstrated that both TF and TFPI may be indicators for the course and the outcome of cardiovascular and other diseases. Based on experimental and clinical data, TFPI may become an important drug or target for several clinical indications. Tissue factor pathway inhibitor is expected to inhibit the development of postinjury intimal hyperplasia and thrombolic occlusion in atherosclerotic vessels, as well as to be effective in acute coronary syndromes such as unstable angina and myocardial infarction. Of special interest is the inhibition of TF-mediated processes in sepsis and disseminated intravascular coagulation. At present, clinical studies with TFPI are rather limited, so the clinical potential of the drug cannot be property assessed. However, TFPI and its variants are expected to undergo further development and to find indications in various clinical states.

This month in J Lab Clin Med: Issue highlights for August 2002

This month in J Lab Clin Med: Issue highlights for August 2002

Effect of endovascular stent strut geometry on vascular injury, myointimal hyperplasia, and restenosis

Purpose: Early restenosis and the development of myointimal hyperplasia in stented blood vessels have been attributed to deep vascular injury with fracture of the internal elastic lamina (IEL). The purpose of this study was the evaluation of the vascular wall response to superficial injury (without IEL rupture) after balloon angioplasty and intravascular stent placement in porcine arteries and the determination of the effect of stent strut geometry on the degree of vessel injury and early restenosis. Methods: Balloon-expandable stainless-steel stents were placed into the iliac arteries of 10 Sinclair miniature swine that had been fed an atherogenic diet. A Palmaz stent, with rectangular struts and smooth corners, was randomly assigned to one iliac artery (group 1), and a novel stent, which was designed and manufactured in the laboratory with thicker struts and sharper corners specifically to induce large wall stress concentrations, was placed in the contralateral iliac artery (group 2). Intravascular ultrasound scan was used in all deployments to ensure accurate balloon sizing and to avoid stent overexpansion and deep vascular injury. At 90 days after implantation, the animals were killed, the stented vessels harvested, and histomorphometric analysis performed. Results: Deployment of novel stents in group 2 resulted in a statistically higher incidence rate of deep vascular injury (fracture of the IEL) compared with group 1, despite identical balloon size used for deployment (with Student t test, P < .05). Vessels with deep injury showed a 10-fold increase in myointimal thickening compared with those vessels in which the IEL remained intact. A statistically higher restenosis rate was observed for group 2 (33.5% ± 19.90%) compared with group 1 (20.39% ± 14.70%). For both stent designs, there was a trend toward lower degrees of restenosis within the mid-portion of the stent. For superficially injured arteries in both groups, no correlation was observed between the amount of vessel wall/medial layer compression and the development of restenosis from myointimal hyperplasia. Conclusion: Maintenance of an intact IEL is an important factor in the prevention of myointimal hyperplasia and restenosis in stented porcine iliac arteries. The alteration of stent strut height and geometry does not significantly affect restenosis and the development of myointimal hyperplasia in vessels with superficial injury. Superficial injury elicits a response that is independent of stent strut geometry and vessel wall compression. Stent strut profile may, however, increase local vessel wall stress concentrations, leading to IEL rupture and an exaggerated response to injury. (J Vasc Surg 2002;36:143-9.)

IgA nephropathy: effects of clinical indices, ACEI/ATRA therapy and ACE gene polymorphism on disease progression

SUMMARY: In 1985 the authors studied 151 patients with biopsy‐proven IgA nephropathy (IgAN). After a mean follow‐up period of 5 years, 84% had stable renal function, 5% had renal impairment and 11% progressed to end‐stage renal failure (ESRF). The unfavourable prognostic indices were proteinuria &gt; 1 g/day, hypertension, crescents on renal biopsy, glomerulosclerosis and medial hyperplasia of blood vessels. The cumulative renal survival was 89% at 5 years. Fifteen years later, in 2000, with data from the Singapore Renal Registry it was ascertained that 53 patients (35%) had developed ESRF. Using multivariate analysis by the regression model of Cox it was found that serum creatinine, protein selectivity, segmental glomerulosclerosis, crescents and medial hyperplasia were significant predictors of progression. It is also shown that the presence of low‐molecular‐weight (LMW) proteinuria is another index of poor prognosis. Cumulative renal survival of the 151 patients was 65% at 20 years. In a recent study, the response of patients with IgAN to angiotensin‐converting enzyme inhibitor/angiotensin receptor antagonist (ACEI/ATRA) therapy was examined. There were 21 patients in the treatment group and 20 as controls. After 13 ± 5 months of treatment, 10 responders had improved selectivity index (SI; from 0.26 ± 0.07 to 0.18 ± 0.07, P &lt; 0.001), indicating a shift towards selective proteinuria. This was associated with improvement in serum creatinine from a mean of 1.7 ± 0.6 to 1.5 0.6 mg/dL (P &lt; 0.02) and a decrease in proteinuria from a mean of 2.3 ± 1.1 g/day to 0.7 ± 0.5 g/day (P &lt; 0.001). Eight out of 21 patients in the treatment group who had documented renal impairment had improvement in their renal function, three of whom had normalized renal function. The angiotensin‐converting enzyme insertion/deletion (ACE I/D) polymorphism gene was also genotyped in 100 patients with IgAN (32 of whom were in ESRF) and in 90 normal adult subjects. All DD cases were subjected to confirmation with a second polymerase chain reaction (PCR), performed with the insert‐specific forward primer. Similar genotype frequencies were obtained for the 90 normal control subjects (II: 47%, ID: 44%, DD: 9%); for the 68 patients not in ESRF (II: 47%, ID: 46%, DD: 7%) and for the 32 patients with ESRF (II: 53%, ID: 38%, DD: 9%). The genotype frequencies in all three series are in Hardy–Weinberg equilibrium. These results suggest that ACE I/D polymorphism is not a risk factor for IgAN and is not a predictor for its progression. In conclusion the predictors in the progression of IgAN include abnormal renal function at presentation, segmental glomerulosclerosis, crescents, medial hyperplasia of blood vessels, non‐selective proteinuria, LMW proteinuria and failure to respond to antiproteinuria therapy with ACEI/ATRA. However, the D‐allele of ACE gene polymorphism is not a risk factor.

Adenoviral activin a expression prevents intimal hyperplasia in human and murine blood vessels by maintaining the contractile smooth muscle cell phenotype.

Activin A alters the characteristics of human arterial smooth muscle cells (SMCs) toward a contractile, quiescent phenotype. We hypothesize that activin A may prevent SMC-rich neointimal hyperplasia. Here, we study the effect of adenovirus-mediated expression of activin A on neointima formation in vitro and in vivo. Human saphenous vein organ cultures, in which a neointima is formed spontaneously, were infected either with activin A- or lacZ-adenovirus. Activin A-overexpression reduces neointima formation by 78%, whereas no significant reduction was observed after control infection. In addition, the effect of activin A on neointima formation was assessed in vivo in mice with cuffed femoral arteries. In activin A adenovirus-infected mice (IV injection), neointimal hyperplasia is reduced by 77% compared with the SMC-rich neointima in mock-infected or in noninfected mice. Cultured human saphenous vein SMCs and murine aorta SMCs were incubated with activin A and an increased expression of SM22alpha and SM alpha-actin mRNA, and SM alpha-actin protein was demonstrated. Laser-capture microdissection on sections of cuffed murine arteries and subsequent real-time RT-PCR established in vivo induction of SM alpha-actin mRNA in the media of activin A-treated mice. In summary, activin A inhibits neointima formation in vitro and in vivo by preventing SMC dedifferentiation.

IgA nephropathy: effects of clinical indices, ACEI/ATRA therapy and ACE gene polymorphism on disease progression

SUMMARY: In 1985 the authors studied 151 patients with biopsy‐proven IgA nephropathy (IgAN). After a mean follow‐up period of 5 years, 84% had stable renal function, 5% had renal impairment and 11% progressed to end‐stage renal failure (ESRF). the unfavourable prognostic indices were proteinuria &gt; 1 g/day, hypertension, crescents on renal biopsy, glomerulosclerosis and medial hyperplasia of blood vessels. the cumulative renal survival was 89% at 5 years. Fifteen years later, in 2000, with data from the Singapore Renal Registry it was ascertained that 53 patients (35%) had developed ESRF. Using multivariate analysis by the regression model of Cox it was found that serum creatinine, protein selectivity, segmental glomerulosclerosis, crescents and medial hyperplasia were significant predictors of progression. It is also shown that the presence of low‐molecular‐weight (LMW) proteinuria is another index of poor prognosis. Cumulative renal survival of the 151 patients was 65% at 20 years. In a recent study, the response of patients with IgAN to angiotensin‐converting enzyme inhibitor/angiotensin receptor antagonist (ACEI/ATRA) therapy was examined. There were 21 patients in the treatment group and 20 as controls. After 13 ± 5 months of treatment, 10 responders had improved selectivity index (SI; from 0.26 ± 0.07 to 0.18 ± 0.07, P&lt; 0.001), indicating a shift towards selective proteinuria. This was associated with improvement in serum creatinine from a mean of 1.7 ± 0.6 to 1.5 ± 0.6 mg/dL (P&lt; 0.02) and a decrease in proteinuria from a mean of 2.3 ± 1.1 g/day to 0.7 ± 0.5 g/day (P&lt; 0.001). Eight out of 21 patients in the treatment group who had documented renal impairment had improvement in their renal function, three of whom had normalized renal function. the angiotensin‐converting enzyme insertion/deletion (ACE I/D) polymorphism gene was also genotyped in 100 patients with IgAN (32 of whom were in ESRF) and in 90 normal adult subjects. All DD cases were subjected to confirmation with a second polymerase chain reaction (PCR), performed with the insertspecific forward primer. Similar genotype frequencies were obtained for the 90 normal control subjects (II: 47%, ID: 44%, DD: 9%); for the 68 patients not in ESRF (II: 47%, ID: 46%, DD: 7%) and for the 32 patients with ESRF (II: 53%, ID: 38%, DD: 9%). the genotype frequencies in all three series are in Hardy‐Weinberg equilibrium. These results suggest that ACE I/D polymorphism is not a risk factor for IgAN and is not a predictor for its progression. In conclusion the predictors in the progression of IgAN include abnormal renal function at presentation, segmental glomerulosclerosis, crescents, medial hyperplasia of blood vessels, non‐selective proteinuria, LMW proteinuria and failure to respond to antiproteinuria therapy with ACEI/ATRA. However, the D‐allele of ACE gene polymorphism is not a risk factor.

The Role of Adrenomedullin in Cardiovascular and Renal Function.

Adrenomedullin is a potent vasodilating peptide that is expressed in tissues relevant to cardiovascular and renal function, such as the heart, kidney, aorta, lung and brain. Adrenomedullin participates in blood pressure homeostasis, and cardiovascular and renal function, as demonstrated in adrenomedullin transgenic mice and knockout mice. Using gene transfer approaches, we have shown that a single injection of adenovirus carrying the adrenomedullin gene results in a prolonged reduction of blood pressure for several weeks, and improved cardiac and renal function in pressure- or salt-induced hypertensive rat models and streptozotocin-induced diabetic rats. Adrenomedullin gene transfer also protects against cardiac and renal damages including: 1) myocardial infarction, ventricular arrhythmias and apoptosis in ischemic myocardium; 2) cardiac hypertrophy and fibrosis; 3) glomerulosclerosis, tubular disruption, protein cast accumulation in lumen, renal cell proliferation and fibrosis in the kidney; 4) neointimal hyperplasia in blood vessels induced by balloon angioplasty; 5) streptozotocin-diabetic­induced cardiac and renal glycogen accumulation, and body weight loss; and 6) cerebral ischemia-induced infarction and locomotor deficits. Adrenomedullin gene delivery results in increased cAMP, nitric oxide and cGMP levels in conjunction with significantly reduced superoxide production in the heart, kidney and brain. These results indicate that adrenomedullin plays important roles in cardiovascular and renal diseases via suppression of oxidative stress production through activation of second messengers cAMP and nitric oxide­cGMP-dependent signaling pathways. These findings provide important insights into the action of adrenomedullin as an antioxidant in protecting cardiovascular and renal dysfunction induced by hypertension, salt loading, vascular injury, diabetes and ischemia-reperfusion injury. (c) 2002 Prous Science. All rights reserved.

Tissue-specific expression of an anti-proliferative hybrid transgene from the human smooth muscle alpha-actin promoter suppresses smooth muscle cell proliferation and neointima formation.

The retinoblastoma protein (Rb), a key regulator of cell cycle progression, can bind the transcription factor E2F converting it from a positive transcriptional factor capable of driving cells into S phase into a negative complex which arrests cells in G1. We have created a potent transcriptional repressor of E2F-dependent transcription by fusing the C-terminal fragment of Rb (p56) to the DNA and DP1-binding domains of E2F. Because the expression of E2F/56 fusion protein from a constitutive promoter was incompatible with virus growth, adenovirus constructs were prepared where transgenes were expressed from a fragment of the smooth muscle alpha-actin (SMA) promoter. Immunoblot and beta-galactosidase staining demonstrated smooth muscle-specific expression of this transcriptional element in vitro. The SMA-p56 and SMA-E2F/p56 adenoviral constructs also induced G0/G1 cell cycle arrest specifically in smooth muscle cells. Following administration to rat tissues, the SMA-beta-galactosidase construct exhibited expression in balloon-injured carotid arteries, but not in liver, bladder or skeletal muscle. Local delivery of the SMA-E2F/p56 adenoviral construct to balloon-injured carotid arteries inhibited intimal hyperplasia. Our results demonstrate that local delivery of the SMA-E2F/p56 adenoviral construct can limit intimal hyperplasia in balloon-injured vessels, while avoiding toxicity that could occur from the dissemination and expression of the viral transgene.

The Fate of Autogenous Free-Fat Grafts After Posterior Lumbar Surgery

Histologic changes of free-grafted fat were investigated from surgical specimens taken at repeated lumbar surgery in 18 patients with degenerative spinal disease who previously had undergone posterior lumbar decompression and free fat graft. To clarify the clinical usefulness of free-grafted fat by histologic analysis. The clinical postoperative serial magnetic resonance imaging studies in Part 1 showed that the size of grafted fat was reduced, and that the shape changed along with the shape of the dura mater. The shape of the grafted fat was remodeled in relation to the postoperative transient shrinkage and reexpansion of the dura mater. From repeated surgery cases, the status of the previously grafted fat tissue in the virgin operation was analyzed. Sections from the specimens resected surgically during repeated surgery were stained with hematoxylin and eosin or osmium. The size and quality of the grafted fat globules were analyzed by computer. In all cases, grafted fat tissue was identified as a survival. Hematoxylin and eosin staining showed increased collagen fiber and hyperplasia of blood vessels entering the fat tissue that survived. From osmium staining, the size of fat globules was reduced. The shape and quality of the fat globules were analyzed by original staging. They showed various sizes, polymorphism, and vacuolar degeneration. Finding showed that the grafted fat used in posterior lumbar surgery reduced the size and quality of the fat globules, as compared with normal fat tissue. However, the grafted fat tissues were confirmed to be alive over the long term. This study clarified the fate of the grafted fat as observed by magnetic resonance imaging and histology from repeated surgery cases.

Immunohistochemical Analysis of Platelet-derived Growth Factor-B Expression in Myocardial Tissues In Hypertrophic Cardiomyopathy

Intimal and/or medial hyperplasia of intramyocardial small vessels is thought to be one of the causes of myocardial ischemia in hypertrophic cardiomyopathy (HCM). However, the pathogenesis of such vascular lesions in HCM is not yet known. To evaluate the pathogenic role of platelet-derived growth factor (PDGF-B) and basic fibroblast growth factor (b-FGF), which have a potential to induce cellular and molecular changes observed in the vessels in HCM, we examined the expression of these molecules and PDGF receptors in cardiac tissues from six patients with HCM and seven controls using immunohistochemistry. The percentage of PDGF-B positive cells in the myocyte population in HCM was significantly higher than that in controls (52.6 ± 16.2 (mean ± SD) vs. 21.6 ± 9.6, p < 0.01). PDGF-B was also observed in vascular regions in HCM (61.1 ± 25.5% of arterioles) but not in controls. There were no significant differences in the expression of b-FGF and PDGF receptors in the myocyte and non-myocyte populations and the vascular regions between the HCM and control groups. Our study revealed that the expression of PDGF-B protein was up-regulated in HCM, suggesting the contribution of this molecule to the development of intramyocardial vasculopathy.