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PubMed2000

Electron beam tomography as an endpoint for clinical trials of antiatherosclerotic therapy.

Current antiatherosclerotic therapies are highly effective and have induced a factual reduction in morbidity and mortality related to atherosclerotic disease. This makes it difficult for clinical researchers to demonstrate a further reduction in hard events. On the other hand, angiographic studies have conclusively demonstrated that coronary artery disease regression can be used as a valid surrogate endpoint. In fact, small improvements in luminal diameter stenosis corresponded to a substantial reduction in event rates. However, because coronary angiography is invasive and expensive, other surrogate endpoints may be more desirable to ascertain the effectiveness of therapy. With electron beam tomography imaging the coronary artery tree is visualized noninvasively and vascular calcification, a marker of atherosclerotic disease, is easily detected and its extent quantified. Preliminary studies have shown that this technology provides an opportunity to serially monitor the effectiveness of medical therapy for coronary artery disease at low cost and low risk for the patient.

Animals↗
PubMed1995

Pancreatic disorders in pediatric acquired immune deficiency syndrome.

Acute pancreatitis, reported in 17% of pediatric patients with acquired immune deficiency syndrome (AIDS), is said to have a poor prognosis. We describe the pancreatic changes observed at autopsy from 71 children with human immunodeficiency virus (HIV) infection and document their nature, extent, and clinical relevance. The median age at autopsy of the children was 17 months (range, 2 months to 19 years); 38 were boys and 33 were girls. Parental intravenous drug use was the most frequent risk factor for AIDS, followed by blood transfusions. Respiratory failure and sepsis constituted the predominant causes of death. Nonspecific changes, such as edema, inflammation, fibrosis, inspissated material in acini and ducts, and enlarged Langerhans' islet predominated. Acute and chronic pancreatitis were mild except in one instance of a fatal acute probably dideoxyinosine-associated pancreatitis. Pancreatic involvement by opportunistic infections, such as cytomegalovirus (CMV), Mycobacterium avium intracellulare (MAI), and Candida, was focal and rare despite the high prevalence of these infections at autopsy. Focal lymphoplasmacytic infiltration and vascular calcifications were also observed. We conclude that pancreatic changes were frequently noted at autopsy in children with AIDS. They were usually mild, reflected systemic disease states, and were usually not life threatening. The incidence of opportunistic infections of the pancreas was low.

AIDS-Related Opportunistic Infections↗
PubMed1994

CT angiography of the pelvic arteries.

UNLABELLED: A comparison was performed between CT angiography and digital subtraction angiography (DSA) on 55 patients with atherosclerotic obstructions of the pelvic arteries. Two post-processing algorithms were employed, maximum intensity projection (MIP) and 3D technique. RESULTS: (a) MIP: conformity with DSA: 20/23 occlusions and 24/36 stenoses; underestimation: three occlusions, seven stenoses; overestimation: five stenoses. (b) 3D display: conformity with DSA: 19/23 occlusions and 16/36 stenoses; underestimation: four occlusions, 17 stenoses; overestimation: three stenoses. The MIP technique proved to be the only method to display the localisation of vascular calcifications with their exact topographical relationship to the stenoses and occlusions. MIP also proved to be valuable in controlling the position of intravascular stents. Complementary to DSA, the MIP method therefore seems to be a clinically valuable technique for calcified and non-calcified stenoses, and for displaying intravascular stents. Its use in interventional procedures could therefore become increasingly important.

Adult↗
PubMed2006

Serum osteoprotegerin is inversely associated with carotid plaque echogenicity in humans.

Osteoprotegerin (OPG) is a member of the tumour necrosis factor superfamily involved in the regulation of bone metabolism and vascular calcification. High serum values of OPG are associated with cardiovascular disease in humans. The purpose was to investigate serum OPG levels in subclinical carotid atherosclerosis and the relation between OPG levels and plaque morphology. OPG levels were compared in 29 persons with echogenic carotid plaques, 30 persons with echolucent plaques and 41 persons without carotid plaques, all recruited from a population health study. Computerized assessment of plaque echogenicity was done by use of the gray scale median (GSM). Participants with echogenic carotid plaques had lower serum OPG level (1.23 ng/ml; 1.02-1.48) (geometric mean; 95% CI) than persons with echolucent plaques (1.76 ng/ml; 1.46-2.14) and those without plaques (1.89 ng/ml; 1.60-2.21). OPG and PTH were independently related to GSM. A significant trend for decrease in GSM across quartiles of OPG was found (p=0.003) which remained significant even after adjustment for PTH and smoking. The present study demonstrates lower serum OPG levels in persons with subclinical echogenic carotid plaques and identified an inverse relation between serum OPG and plaque echogenicity. The findings support the concept that OPG may play an important role in arterial calcification.

Aged↗
PubMed2005

Bone morphogenetic proteins in development and homeostasis of kidney.

Bone morphogenetic proteins play a key role in kidney development and postnatal function. The kidney has been identified as a major site of bone morphogenetic protein (BMP)-7 synthesis during embryonic and postnatal development, which mediates differentiation and maintenance of metanephric mesenchyme. Targeted disruption of BMP-7 gene expression in mice resulted in dysgenic kidneys with hydroureters, causing uremia within 24h after birth. Several experimental animal models of acute and chronic renal injury have all unequivocally shown beneficial effect of BMP-7 in ameliorating the severity of damage by preventing inflammation and fibrosis. Apart from the beneficial effect on kidney disease itself, BMP-7 improves important complications of chronic renal impairment such as renal osteodystrophy and vascular calcification.

Animals↗
PubMed2006

Iron ions derived from the nitric oxide donor sodium nitroprusside inhibit mineralization.

Sodium nitroprusside (SNP) is a nitric oxide (NO) donor drug, which is therapeutically used as a vasodilating drug in heart transplantations. In our previous study it was found that SNP at a concentration of 100 microM inhibited mineralization in a cell culture system, indicating that the beneficial effects of this drug may also include inhibition of vascular calcification. The aim of this study was to investigate which bioactive compounds generated from SNP inhibit mineralization. ATDC5 cells were grown for 14 days and mineralization was induced by addition of 5 mM phosphate for 24 h. Mineralization was determined by staining precipitated calcium with an alizarin red stain. It was found that the NO donors S-nitrosoglutathione and S-nitroso-N-acetylpenicillamine were not able to inhibit mineralization and NO scavengers could not antagonize the inhibiting effect of SNP on mineralization. The iron chelator deferoxamine (200 microM) antagonized the inhibiting effect on mineralization mediated by SNP and ammonium iron sulfate inhibited mineralization in a dose-dependent manner (10-100 microM). Furthermore, iron ions (30 microM) were detected to be released from SNP in the cell culture. These data show that the iron moiety of sodium nitroprusside, rather than nitric oxide inhibits mineralization.

Animals↗
PubMed2005

Differentially expressed cortical genes contribute to perivascular deposition in transgenic mice with inducible neuron-specific expression of TGF-beta1.

In the brain the expression of transforming growth factor beta1 (TGF-beta1) is involved both in neuroprotective and neurodegenerative processes. Recently, we have established a transgenic mouse model with inducible neuron-specific expression of TGF-beta1 based on the tetracycline-regulated gene expression system. A long-term expression of TGF-beta1 results in persisting perivascular thioflavin-positive depositions, which did not disappear even though the transgene synthesis was repressed completely by administration of doxycycline. Formation and composition of these depositions are hardly elucidated. The aim of this study was to identify TGF-beta1 responding genes potentially participating in forming these depositions. To address this problem we have compared the cortical mRNA expression pattern of TGF-beta1 expressing mice with mice impeded to express the transgenic protein using oligonucleotide microarray analysis. Differential gene expression was further characterized by quantitative real-time reverse transcription-polymerase chain reaction including animals, where the long-lasting TGF-beta1 expression was repressed. While no change of amyloid precursor protein RNA expression level was detected, various genes strongly involved in calcium homeostasis, tissue mineralization or vascular calcification were identified differentially expressed. It is suggested, that these genes might contribute to the perivascular depositions in the TGF-beta1 expressing mice.

Animals↗
PubMed2005

The case for dietary calcium restriction in patients with atherosclerosis.

An increasingly vast set of data is linking the process of vascular calcification to the metabolism of calcium and phosphorus. This phenomenon is already relatively well understood in renal failure patients. A similar phenomenon, however, could be taking place in the general population. This may indicate a need for a reassessment of calcium supplementation, including the ingestion of milk, not only in dialysis patients, but also in patients with preserved renal function. Given the fact that no clear prospective randomized evidence exists to show what may be the impact on prognosis of patients with atherosclerosis, caused by the ingestion of milk and milk derivatives, containing calcium and lactose, as is currently recommended to prevent bone disease in the general population, a case could be made to recommend restriction of such dietary products in atherosclerosis patients, until precise data have been obtained, in controlled, prospective studies, and especially so in patients with no evidence of osteoporosis. Such a case would not be a strong one at the present stage, but neither would be the opposite view. The recommendation that could be made at this stage would be that patients with significant atherosclerotic disease should be informed that the ingestion of milk, and calcium supplementation in general, has neither been conclusively proven to be safe, nor the opposite.

Animals↗
PubMed2006

HMG-CoA reductase inhibitors induce apoptosis in pericytes.

Pericytes, which surround endothelial cells in precapillary arterioles, capillaries, and postcapillary venules, are important for the development, maturation, and maintenance of the vascular system. Pericytes are also pluripotent cells that can differentiate into a variety of mesenchymal cells including smooth muscle cells and osteoblasts. Possibly because of their vasculature regulating activities and ability to differentiate in situ, pericytes are implicated in several diseases with vascular complications, including diabetic retinopathy, as well as Reynaud's Syndrome, central nervous system dementias, and vascular calcification among others. Statin drugs, which block the conversion of HMG-CoA to mevalonate in the cholesterol synthesis pathway, are known to have apoptotic and growth inhibitory effects on cells in vitro and complex pleiotropic effects on cells and tissues in vivo. Recently, evidence has emerged that statin drug use in human patients results in a significant 20% reduction in cancer incidence. It is not known whether these results are due to direct statin action on normal tissue, growth inhibitory/pro-apoptotic effects on tumor cells, and/or effects on angiogenesis. Because of the role of pericytes in angiogenesis and the effects of statins on cancer incidence, we tested the direct effects of statins on pericytes. Specifically, we demonstrate that 3 statins, simvastatin, lovastatin, and mevastatin induce dose-dependent apoptosis in the TR-PCT1 pericyte cell line, that simvastatin (empirically shown to be the most potent of the 3 statins) induces similar levels of apoptosis in freshly isolated pericytes, and that simvastatin-induced apoptosis in pericytes is cholesterol, caspase-3, and caspase-7 mediated.

Animals↗
PubMed2005

Subdural hematoma as clinical presentation of osteogenesis imperfecta.

Osteogenesis imperfecta is an inherited collagenous disease. The mildest form may present with less severe findings, for example blue sclera, but can also lead to significant handicap such as deafness or multiple bone fractures. We describe an 11-month-old female in whom bilateral chronic subdural hematoma was the leading clinical presentation of osteogenesis imperfecta type I. She was hospitalized due to epileptic seizures caused by these bilateral subdural hematomas without preceding trauma. Osteogenesis imperfecta type I was diagnosed on the basis of clinical and radiologic findings. This case demonstrates that nontraumatic chronic subdural hematoma in patients with osteogenesis imperfecta type I may be caused by impaired bone calcification, vascular fragility, and permanent friction between multiple bone fragments of the skull. Osteogenesis imperfecta type I should be considered as an underlying disease in cases of nontraumatic subdural hematoma. A thorough clinical examination is recommended to exclude subtle characteristics of the disease.

Female↗
PubMed2001

The use of electron-beam computed tomography as a tool for primary prevention.

Coronary artery disease (CAD) is the most common cause of death in the United States, and most acute CAD events occur unexpectedly in patients unaware of their condition. Consequently, attention has recently focused on the development of new technologies for the early detection of CAD, such as electron-beam computed tomography (EBCT). With EBCT imaging, the coronary artery tree is visualized noninvasively and vascular calcification, a marker of atherosclerotic disease, is easily detected and its extent quantified. Current research suggests that the presence of coronary artery calcification on a screening EBCT image provides relevant prognostic information for the development of future coronary events. Furthermore, preliminary evidence suggests that the use of EBCT to observe the progression of disease, as demonstrated by changes in the coronary calcium burden on sequential studies, is a viable and exciting new application. The Beyond Endorsed Lipid Lowering with EBCT Scanning (BELLES) trial will use EBCT to compare the effects of 12 months of treatment with aggressive or moderate statin therapy on the progression of coronary atherosclerosis.

Adult↗
PubMed2003

Chronic inhibition of cyclooxygenase-2 does not alter plaque composition in a mouse model of advanced unstable atherosclerosis.

OBJECTIVE: Inflammation contributes to atherosclerotic plaque initiation and progression. Recent studies suggest that anti-inflammatory drugs such as cyclooxygenase-2 (Cox-2) inhibitors have anti-atherogenic effects. The current study was designed to investigate whether administration of a Cox-2 inhibitor to older apolipoprotein E deficient (apo E-/-) mice with established lesions alters the composition and increases the stability of the lesions. METHODS AND RESULTS: The Cox-2 inhibitor Celecoxib was administered in chow to 26-week-old, male, apo E-/- mice exhibiting advanced, unstable atherosclerotic lesions within the innominate/brachiocephalic artery. Mice administered Celecoxib had no significant changes in serum cholesterol or the average cross sectional area of atherosclerotic lesion in the innominate artery after 15 weeks of treatment in comparison to non-treated control mice. Histological analyses of sections of the innominate artery demonstrated no significant changes in the frequency of markers of advanced and unstable atherosclerotic plaques, including intra-plaque hemorrhage, vascular calcification, thinning of the fibrous cap, size of the necrotic core and macrophage content. There were also no significant differences in the content of Cox-2 within the lesions. Quantitative real time polymerase chain reaction with mRNA isolated from the aorta of each mouse revealed no significant changes in the expression of tissue factor and inducible nitric oxide synthase. However, mRNA levels for MCP-1 were increased fivefold following 15 weeks of treatment with Celecoxib in comparison to non-treated control mice. CONCLUSIONS: These data suggest that Celecoxib has no effect on the composition of advanced atherosclerotic lesions in older apo E-/- mice.

Actins↗
PubMed2002

pH Heterogeneity of human and rabbit atherosclerotic plaques; a new insight into detection of vulnerable plaque.

BACKGROUND: Atherosclerotic plaques are heterogeneous with respect to inflammation, calcification, vascularity, oxygen, and temperature. We hypothesized that they also vary in pH and measured pH in living human carotid endarterectomized atherosclerotic plaques (CEA), Watanabe heritable hyperlipidemic (WHHL) rabbit aortas and human umbilical arteries (HUA). METHODS AND RESULTS: We measured pH of CEA of 48 patients, nine WHHL rabbit aortas and 11 HUA specimens (as controls) using a glass type microelectrode mounted on a micromanipulator in a 37 degrees C incubator. We also used single emission and also dual emission fluorescence ratio imaging microscopy employing pH-sensitive probes to confirm pH heterogeneity. Mean pH measured at 415 points of CEA was 7.55+/-0.32; at 275 points of WHHL rabbit aortas it was 7.40+/-0.43; and in 233 points of HUA it was 7.24+/-0.1. In CEA, pH of yellow (lipid-rich) areas was significantly lower than pH in calcified areas (7.15+/-0.01 vs. 7.73+/-0.01, P<0.0001). The coefficients of variation (heterogeneity) of pH in CEA, WHHL rabbit aortas, and HUA were 0.038+/-0.010, 0.039+/-0.007, and 0.009+/-0.003, respectively (P=0.0001). Fluorescence microscopic imaging confirmed pH heterogeneity in both humans and rabbits but not in HUA. In a variance components analysis 82% of the heterogeneity was due to the within-plaque variation and 2% was attributable to between-plaque variation. CONCLUSIONS: Our findings support the hypothesis of pH heterogeneity in plaques, and suggest a possible role for detecting low pH in the detection of plaque vulnerability. The source of pH heterogeneity particularly acidic pH, its impact on the stability of plaques and its potential clinical utility in locating vulnerable plaques remain to be evaluated.

Animals↗
PubMed1984

Penile gangrene: a complication of secondary hyperparathyroidism from chronic renal failure.

We present the third case and first reported survivor of penile gangrene due to secondary hyperparathyroidism from chronic renal failure. The patient was treated with distal penectomy and subtotal parathyroidectomy. This case stimulated us to review the metabolic and vascular changes associated with secondary hyperparathyroidism in chronic renal failure. Secondary hyperparathyroidism may cause diffuse vasculitis and vascular calcification, which can lead to widespread ischemic necrosis and gangrene. Early medical therapy, including oral phosphate binders, is crucial to maintain the serum calcium-phosphate product below precipitation level. Subtotal parathyroidectomy is indicated for patients in whom progressive arterial and soft tissue calcification develops despite medical therapy.

Gangrene↗
PubMed2001

Wet gangrene in hemodialysis patients with calciphylaxisis is associated with a poor prognosis.

Calciphylaxis is a rare syndrome characterized by progressive vascular calcification and ischemic tissue loss in patients with chronic renal failure. We report our five-year experience with five patients who developed foot gangrene due to calciphylaxis. All five patients had characteristic clinical, laboratory, and radiologic findings of the disorder, but no diagnostic variable was uniformly present. All five had progressed to advanced gangrene at the time of surgical consultation. Despite aggressive local attempts to control infection, all five patients died of septic complications. Parathyroidectomy was performed in three patients but did not alter the course in any case. This small experience suggests that the outcome of foot gangrene associated with calciphylaxis is predicated on the degree of tissue loss. Aggressive local wound care does not appear to be adequate to control infection in patients who have already developed gangrene. Although parathyroidectomy may have important long-term advantages in patients with calciphylaxis, it does not appear to affect outcome in these advanced cases.

Adult↗
PubMed2002

Is clinical expressiveness of Paget's disease of bone decreasing?

Recent data have suggested secular changes implying a current trend toward decreased clinical severity of Paget's disease of bone (PD). To test this hypothesis, we conducted a study comparing the characteristics of two groups of PD patients, as disclosed from a sample assessed systematically. The investigation was a hospital-based study of all cases followed up at our unit since 1980. Throughout the follow-up period, diagnosis was based on standard X-ray criteria and the same clinical assessment was applied. Group I (n = 124) represented patients born before 1926, whereas group II (n = 109) included those born after that year. A bone scan performed with 99mTc-EHDP was available for all patients. X-rays of the pelvis and spine, and views of any hot spot observed on the scintigraphy scans were reviewed. The skeletal extent of PD, based on bone scan uptake, was determined by using the index proposed by Coutris. Alkaline phosphatase and hydroxyproline excretion levels were determined in blood and urine, respectively. Baseline characteristics were recorded on a purpose-designed computerized database. The proportion of males (47% in group I vs. 65% in group II; p = 0.007) and the mean (+/-SD) age at diagnosis (69.0 +/- 8.15 vs. 54.3 +/-9.14; p < 0.001) differed significantly between groups. The year of birth showed a strong negative correlation with age at diagnosis (r = -0.83, p < 0.0001) and a weak, but significant, negative correlation with extent of bone lesion (r = -0.20; p = 0.002). Likewise, subjects born prior to 1926 showed a greater percentage of affected skeleton cases (9.6 plus minus 8.01 vs. 7.06 +/- 5.79; p = 0.001). Group I individuals who had pelvic and/or femoral bone lesions were more prone to suffer "pagetic coxopathy" (65% vs. 40%; p = 0.003) with "protrusio acetabuli" (32% vs. 17%; p = 0.01), and the percentage of patients showing radiographic Monckeberg-type vascular calcifications (36% vs. 14%; p = 0.0006) was higher than in those born after 1926. No other epidemiologically clinically, or biochemically relevant differences were seen in the crude analysis. Multivariate analysis identified extent of skeletal lesions (OR = 0.76; p = 0.01), age at diagnosis (OR = 0.79; p = 0.008), number of bones involved (OR = 1.53; p = 0.03), and occupation (p < 0.0001) as the predictive variables linked to year of birth. Our data are consistent with a temporal tendency toward a smaller number of bone lesions and a decreased percentage of instances of affected skeleton. An earlier age at recent diagnosis times and absence of any relevant clinical or biochemical differences seems more likely linked to recent changes in referral and sociological patterns.

Age Distribution↗
PubMed2006

Basic and clinical aspects of parathyroid hyperplasia in chronic kidney disease.

Marked parathyroid hyperplasia develops in patients with chronic kidney disease, especially those with long dialysis vintage. Although progression of hyperplasia is associated with downregulation of vitamin D receptor and calcium-sensing receptor, initial abnormality that triggers and maintains parathyroid cell proliferation, as well the critical abnormality for the progression of diffuse hyperplasia to nodular hyperplasia, still remains to be elucidated. It is quite important for the optimal management of renal osteodystrophy to recognize the development of nodular hyperplasia, because the cells in nodular hyperplasia are usually resistant to medical therapy and further treatment of such patients often leads to vascular calcification. For this purpose, size and blood supply of enlarged parathyroid glands have been used as good clinical markers. Furthermore, we have recently shown that the serum fibroblast growth factor 23 level can be used for predicting refractory hyperparathyroidism. Once nodular hyperplasia develops in any of the enlarged parathyroid glands, such patients need to be treated by parathyroid intervention including percutaneous ethanol injection therapy. In addition, as direct vitamin D injection therapy has been shown to induce regression of hyperplasia, it may become possible to reverse or normalize established nodular hyperplasia if we can develop new agents with such effects in the near future.

Anti-Infective Agents, Local↗
PubMed2006

Correlation of simple imaging tests and coronary artery calcium measured by computed tomography in hemodialysis patients.

Vascular calcification is associated with an adverse prognosis in end-stage renal disease. It can be accurately quantitated with computed tomography but simple in-office techniques may provide equally useful information. Accordingly we compared the results obtained with simple non-invasive techniques with those obtained using electron beam tomography (EBT) for coronary artery calcium scoring (CACS) in 140 prevalent hemodialysis patients. All patients underwent EBT imaging, a lateral X-ray of the lumbar abdominal aorta, an echocardiogram, and measurement of pulse pressure (PP). Calcification of the abdominal aorta was semiquantitatively estimated with a score (Xr-score) of 0-24 divided into tertiles, echocardiograms were graded as 0-2 for absence or presence of calcification of the mitral and aortic valve and PP was divided in quartiles. The CACS was elevated (mean 910+/-1657, median 220). The sensitivity and specificity for CACS > or = 100 was 53 and 70%, for calcification of either valve and 67 and 91%, respectively, for Xr-score > or = 7. The area under the curve for CACS > or = 100 associated with valve calcification and Xr-score was 0.62 and 0.78, respectively. The likelihood ratio (95% confidence interval) of CACS > or = 100 was 1.79 (1.09, 2.96) for calcification of either valve and 7.50 (2.89, 19.5) for participants with an Xr-score > or = 7. In contrast, no association was present between PP and CACS. In conclusion, simple measures of cardiovascular calcification showed a very good correlation with more sophisticated measurements obtained with EBT. These methodologies may prove very useful for in-office imaging to guide further therapeutic choices in hemodialysis patients.

Adult↗