Les pathologies cardiovasculaires sont le plus souvent l’aboutissement des processus liés à l’athérosclérose. Elles représentent la première cause de morbi-mortalité dans le monde et leur incidence s’accroit avec le vieillissement de la population et l’expansion de facteurs de risques comme le diabète ou l’obésité. La sténose valvulaire aortique (SVA) est la valvulopathie la plus fréquente dans les pays développés présentant de nombreux points communs avec l’athérosclérose vasculaire. En plus des facteurs de risque, les lésions valvulaires et les lésions vasculaires partagent des similitudes dans les processus physiopathologiques impliqués comme l’inflammation, la fibrose, l’angiogenèse et la calcification. Ce dernier processus apparait dans les stades avancés des pathologies liées à l’athérosclérose et joue un rôle critique via son implication dans la stabilité de la plaque ou l’épaississement des cuspides valvulaires aortiques. Les macrophages, cellules issues de la différenciation des monocytes infiltrés, jouent un rôle prépondérant dans ces lésions via les phénotypes classiques (M1) et alternatifs (M2). Néanmoins cette dichotomie ne reflète pas complètement la variété de leur plasticité et les différents phénotypes induits notamment par le microenvironnement des monocytes/macrophages (zones riches en lipides, zones riches en fer ou zones riches en calcification). Dans la valve aortique, les cellules interstitielles de valve (VIC) forment la population cellulaire la plus présente au sein de la valve aortique. Ces cellules jouent un rôle déterminant dans le maintien du tissu valvulaire, mais également dans les processus de calcification menant à la SVA. Dans un premier temps, cette thèse a pour but d’étudier la capacité des macrophages à former des ostéoclastes, cellules responsables de la dégradation de la matrice osseuse, au sein des plaques d’athérosclérose. Dans un second temps, ce travail se focalisera sur les processus de calcification de la valve aortique via l’étude du rôle de la leptine dans les calcifications valvulaires (étude a priori) puis dans une étude transcriptomique sans a priori de VIC issues de valve sténosées et non-sténosées. Nos résultats sur les macrophages montrent ex vivo que les cellules en bordure des calcifications vasculaires sont des macrophages alternatifs de type M2. In vitro, ces cellules sont incapables de se différencier en ostéoclastes et de résorber une matrice osseuse. Pour l’étude de l’effet de la leptine sur les VIC, nous montrons que la leptine sérique est plus élevée chez des patients présentant une SVA, nous confirmons que la leptine et son récepteur sont exprimés au sein des valves aortiques et que la leptine favorise la différenciation ostéoblastique des VIC de manière dépendante des voies Akt et ERK. Enfin, l’étude transcriptomique a permis de mettre en évidence une nouvelle voie métabolique dérégulée dans les VIC. Cette enzyme est sous exprimée dans les VIC issues de valves pathologiques et dans les zones calcifiées des valves aortiques sténosées. Par ailleurs, le traitement des VIC par le produit de cette enzyme en milieu procalcifiant inhibe la calcification. Cette thèse met en avant de nouveaux indices sur les processus de calcification observés dans les plaques d’athérosclérose et les valves aortiques sténosées. Ces résultats décrivent l’impossibilité des M2 à former des ostéoclastes capables de résorber les calcifications. Il sera intéressant d’étudier le phénotype des macrophages en bordure des calcifications des valves aortiques sténosées. D’autre part, il sera intéressant d’étudier l’origine de la leptine dans la valve et son mécanisme d’action sur les VIC. Enfin, ce travail a mis à jour une nouvelle voie métabolique, impliquée dans le développement des calcifications valvulaires, qui pourrait constituer une voie thérapeutique innovante dans le traitement médicamenteux de la SVA. / Cardiovascular diseases (CVD) are the most often outcome of atherosclerosis processes. CVD are the first leading cause of death rate with an increasing incidence due to ageing populations and expansion of risk factors such as diabetes mellitus or obesity. Aortic valve stenosis (AVS) is the most frequent valvulopathy in developed countries sharing common points with vascular atherosclerosis. More than only risk factors, valvular and vascular lesions share common pathophysiological processes implicated in the development of the disease such as inflammation, fibrosis, angiogenesis and calcification. This last process appears in late stages of atherosclerosis diseases and play critical roles via implication in plaque stability or thickening of the aortic valve. Macrophages are cells deriving from infiltrated monocytes, playing an important role in the inflammatory state of lesions via classical (M1) or alternative phenotypes (M2) phenotypes. Nevertheless, this dichotomy does not reflect completely the variety of their plasticity and different phenotypes induced by the microenvironment of monocytes/macrophages (lipid riche zone, iron riche zone or calcium rich zone). In the aortic valve, valvular interstitial cells (VIC) are the most prominent cell type found in the aortic valve. These cells play a major role not only in the valve tissue homeostasis but also in the calcification processes leading to AVS. In a first part, the aim of this thesis is to elucidate the ability of macrophages to differentiate into osteoclasts, cell type responsible for bone matrix remodeling, inside atherosclerosis plaques. In a second part, this work will focus on the calcification processes occurring in the aortic valve via the study of the role of leptin in valvular calcification (association study) and then in a transcriptomic analysis of VIC isolated from calcified versus non calcified aortic valves (genome-wide expression study). Our results about macrophages show that ex vivo cell surrounding vascular calcification are alternative M2 macrophages. In vitro, these cells are no able to differentiate into true osteoclasts nor to resorb calcium deposits. Concerning the role of leptin on VIC, the results show that serum leptin is higher in patients with AVS, leptin and its receptors are expressed in the aortic valves and leptin enhances the osteoblast différenciation of VIC in an Akt and ERK dependant manner. Finally, the transcriptomic analysis allowed to highlight a new pathway deregulated in VIC. This enzyme is underexpressed in VIC isolated from calcified aortic valves and in the calcified zonesAbstract4of stenosed aortic valves. Otherwise, treating VIC with the product of this enzyme in a procalcifying medium inhibits calcification processes.This thesis highlights new insights into the calcification processes occurring in atherosclerosis lesions and calcified aortic valves. These results describe that M2 macrophages cannot differentiate into osteoclasts and reverse calcification formation inside atherosclerosis plaques. In parallel, it would be interesting to study the macrophages phenotypes surrounding calcium deposits in stenosed aortic valves. Then, it will be interesting to decipher the origin of leptin and its precise mechanism of action on VIC. Finally this work points out a new metabolic pathway implicated in the development of valvular calcification which could be a medical treatment of SVA.

Introdução: As doenças cardiovasculares (DCV) são a principal causa de morte no mundo, sendo a doença arterial coronária (DAC) a mais comum das DCV, juntamente com acidente vascular cerebral. O cálcio das artérias coronárias é um marcador da DAC subclínica (assintomática) e é preditivo de eventos coronários futuros. Vários fatores de risco cardiovascular contribuem para o desenvolvimento da calcificação da artéria coronária (CAC). Adicionalmente, os fatores dietéticos podem influenciar no processo de aterosclerose e CAC. Objetivo: Avaliar a CAC e sua associação com fatores de risco cardiovascular e ingestão dietética em homens assintomáticos vivendo em comunidade. Métodos: Estudo transversal. A amostra consistiu de 150 homens assintomáticos com idades entre 50 e 70 anos (idade média 58,2 ± 5,3 anos), que foram submetidos à tomografia computadorizada multidetectores (TCMD). A aterosclerose subclínica foi avaliada pela CAC de acordo com o método de Agatston, sendo os escores de cálcio classificados como ≤10 (sem evidência e CAC mínima) e >10 (CAC moderada e aumentada). A ingestão dietética foi avaliada através do Registro de Consumo Alimentar (RCA). O modelo multivariado de Regressão de Modified Poisson foi utilizado para avaliar os fatores de risco cardiovascular independentemente associados com a CAC moderada/aumentada, sendo estimados os efeitos do consumo de diversos nutrientes na prevalência de CAC moderada/aumentada ajustado para ingestão calórica e fatores de risco para CAC, através da razão de prevalências e intervalo de 95% de confiança. Resultados: A presença de CAC (escore de cálcio >0) foi identificada em 59,3% dos participantes. Na análise multivariada, os fatores independentemente associados com a CAC moderada/aumentada foram a história familiar (HF) de DAC prematura (RP=1,39; IC95% 1,03-1,88, p=0,029) e a atividade física (AF) <150 minutos/semana (RP=1,40; IC95% 1,01-1,93; p=0,045). O consumo de alguns nutrientes, também, mostrou-se associado à CAC moderada/aumentada, como o menor consumo de carboidratos (p=0,021) e o maior consumo de lipídeos (p=0,006), após o ajuste do modelo para a quantidade de calorias. Com a inclusão no modelo dos fatores de risco cardiovascular e escolaridade, os nutrientes associados à prevalência da CAC moderada/aumentada foram: carboidratos percentual (RP=0,98; IC95% 0,96-0,99; p=0,040), lipídeos percentual (RP=1,04; IC95% 1,01-1,07; p=0,005) e ácidos graxos saturados (AGS) percentual (RP=1,08; IC95% 1,02-1,14; p=0,013). Conclusões: Nesta amostra de adultos e idosos assintomáticos vivendo em comunidade, fatores de risco cardiovascular como HF de DAC prematura e baixa intensidade de AF estiveram associados, de forma independente, com a calcificação coronária moderada a aumentada. Analisando os fatores dietéticos, uma maior ingestão de lipídeos totais e de gorduras saturadas mostraram-se associadas com escores mais elevados de CAC, enquanto que a ingestão maior de carboidratos, em detrimento aos lipídeos, associou-se com escores mais baixos de CAC. Nossos resultados sugerem que esses fatores de risco devem ser mais considerados na avaliação clínica do risco cardiovascular global do paciente. / Introduction: Cardiovascular diseases (CVD) are the main cause of death in the world, being the coronary artery disease (CAD) the most common CVD. The calcium of the coronary arteries is a marker for subclinical (asymptomatic) CAD, and is predictive of future coronary events. A number of cardiovascular risk factors account for coronary artery calcification (CAC). In addition, dietary factors may influence the process of atherosclerosis and CAC. Goal: To assess CAC and its association with cardiovascular risk factors and dietary intake in community-dwelling asymptomatic men. Method: Cross-sectional study. The sample included 150 asymptomatic men with age ranging between 50 and 70 years (mean age 58.2 ± 5.3 years) submitted to multidetector computed tomography (MDCT). Subclinical atherosclerosis was measured by CAC in accordance with the Agatston method, with the scores classified as ≤10 (no evidence of, or mild CAC) and >10 (moderate and severe CAC). Dietary intake was assessed according to the Food consumption Register (RCA) method. The multivariate Modified Poisson regression model was used to assess cardiovascular risk associated with moderate/severe CAC and the effects of the intake of different nutrients were estimated for the prevalence of moderate/severe CAC, adjusted for calorie intake and CAC risk factors by means of prevalence ratios and 95% confidence intervals. Results: CAC (calcium score >0) was present in 59.3% of the subjects. In the multivariate analysis, factors independently associated with moderate/severe CAC included family history (FH) of early CAD (PR=1.39; 95%CI 1.03-1.88, p=0.029) and physical activity (PA) <150 minutes/week (PR=1.40; 95%CI 1.01-1.93; p=0.045). The intake of some nutrients was also associated with moderate/severe CAC, such as lower carbohydrate intake (p=0.021) and higher lipid intake (p=0.006), after model adjustment for the amount of calories. Once the cardiovascular risk factors and schooling were included in the model, the nutrients associated with the prevalence of moderate/severe CAC were: percentage of carbohydrates (PR=0.98; 95%CI 0.96-0.99; p=0.040), percentage of lipids (PR=1.04; 95%CI 1.01-1.07; p=0.005), and percentage of saturated fatty acids (SFA) (PR=1.08; 95%CI 1.02-1.14; p=0.013). Conclusions: In the sample of community-dwelling asymptomatic adults and older persons, cardiovascular risk factors such as FH of early CAD, and low-intensity PA were independently associated with moderate to severe coronary calcification. Analysis of dietary factors showed that higher intake of total lipids and saturated fats were associated with higher CAC scores, whereas higher intake of carbohydrates over lipids was associated with lower CAC scores. Our results indicate that these risk factors should be considered in the cardiovascular assessment of the patient.

by Tang Shengping. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 217-244). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

The cardiovascular system is an essential component of mammalian biology. It is a complex network of various tissues and structures with unique functions. The function of the cardiovascular system is to supply nutrients including oxygen to the various cells, tissues and organs within the body, and remove waste products from them. Given the importance of this role, it is not surprising that there are countless regulatory mechanisms at the molecular, cellular and tissue levels that are required to support this functional system. Perturbations in parts of this system are likely to lead to abnormalities, and thus give rise to cardiovascular-related diseases. Despite the currently expanding list of genes reported to be involved in a variety of cardiovascular-related diseases, including calcific aortic valve disease (CAVD), the functions and associated pathways of these factors in both normal and pathological physiology have yet to be fully understood, such as at the transcriptomic level. In this thesis, a genome-wide transcriptomic atlas of the healthy mammalian cardiovascular system was generated using the sheep as a large animal model. This atlas was generated using RNA-seq, with the aim of further understanding normal gene expression patterns in the context of the known physiology of healthy mammalian tissues. Through this work, I identified novel gene networks and detailed functional clustering of co-expressed genes with region-specific expression and specialised cardiovascular roles. One interesting cluster was highly expressed in the cardiac valves, and shared genes found in physiological bone development, such as bone morphogenetic protein 4 (BMP4), collagen type I alpha 2 (COL1A2), Sry homeobox 8 (SOX8) and bone gamma-carboxyglutamate protein (BGLAP), some of which have been implicated in vascular calcification. Further to this work, I studied the expression profiles of these key cardiovascular genes during development in the sheep from foetal to adult stages. In addition, I investigated the gene expression patterns of various key vascular calcification genes. These studies showed differential expression of genes in the different cardiovascular tissues, demonstrating transcriptional differences between these different tissues known to have different functions. CAVD involves progressive valve leaflet thickening and severe calcification, resulting in impaired leaflet motion. The in vitro calcification of primary rat, human, porcine and bovine aortic valve interstitial cells (VICs) is commonly employed to examine the mechanisms of CAVD. However, to date, no published studies have utilised cell lines to investigate this process Thus, in this project, I generated and evaluated the calcification potential of an immortalised cell line derived from sheep aortic VICs (SAVICs). This novel large animal in vitro model of CAVD was demonstrated to calcify under high calcium and phosphate conditions. Changes in the expression of key calcification genes during VIC calcification was also observed, including increased mRNA expression of bone markers Runt-related transcription factor 2 (RUNX2) and sodium-dependent phosphate transporter 1 (PiT1), and a concomitant decrease in matrix Gla protein (MGP) mRNA expression. In addition, the role of extracellular nucleotides and their receptors (P2 receptors), which have been previously shown to be important in bone and vascular calcification, were investigated using SAVICs in vitro. This study has shown that extracellular nucleotides, particularly adenosine 5’-triphosphate (ATP) and uridine 5’-triphosphate (UTP) and other agonists of P2 receptors, reduced VIC calcification in vitro. Moreover, the cutting-edge gene-editing technology, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9), was successfully applied to generate large animal models of cardiovascular-related diseases. In this project, I applied the CRISPR/Cas9 technology to edit ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and fibrillin 1 (FBN1) to generate two models of vascular calcification and Marfan Syndrome (MFS), respectively. In the ENPP1-edited animals, soft tissue calcification has been observed in the biallelic mutant and homozygous pigs. In this project, I have developed a range of novel in vitro and in vivo tools to advance the study of cardiovascular disease. These studies demonstrate that large animal models are highly valuable in the field of cardiovascular biology. The in vivo and in vitro experimental models described should facilitate detailed analysis of cardiovascular molecular biology and ultimately lead to therapies which will minimise the morbidity and mortality currently arising from cardiovascular pathology.

Orientador: Jacqueline Costa Teixeira Caramori / Banca: João Egídio Romão / Banca: Luís Cuadrado Martin / Banca: Pasqual Barretti / Banca: Rodrigo Bueno de Oliveira / Resumo: A doença cardiovascular é a principal causa de mortalidade nos pacientes com doença renal crônica (DRC) em programa de hemodiálise e a calcificação vascular (CV) é comum nesta população. O principal objetivo deste estudo foi avaliar a associação de marcadores do metabolismo mineral e ósseo com a presença e progressão da CV em uma coorte de pacientes em diálise; secundariamente, objetivou identificar as associações clínicas, laboratoriais e da composição corporal sobre a presença e progressão da CV. Foram incluídos maiores de 18 anos em diálise crônica há mais de 90 dias. Os pacientes foram submetidos à biópsia óssea no início do seguimento e analisados dados de histomorfometria. Para investigar CV foi utilizada a somatória dos índices radiológicos de Kauppila e Adragão em dois momentos, no início, coincidindo com a realização da biópsia óssea e após 12 meses. Além da investigação para CV foram realizadas avaliações clínicas, hormonais, inflamatórias, bioquímicas e nutricionais. Resultados: 60 pacientes completaram o estudo, 41,7 % do sexo feminino, 43,4% diabéticos, média de idade de 56 anos, variação de 25 a 89 anos. No seguimento, 75% dos pacientes apresentavam CV e a progressão ocorreu em 56,86%. Na análise multivariada, a idade > 60 anos (Odds ratio=50.2, 95%CI= 4.1-618,4, p=0.002), FGF23 > 3000 Ru/ml (Odds ratio=5.7, 95%IC= 1,00-329, p=0.05), e fetuína A >673 μ/l (Odds ratio=7.34, 95%CI= 1,26-43,7, p=0.03) estiveram associados com a CV. Para progressão da CV, a associação foi mostrada para idade > 60 anos (Odds ratio=4.3, 95%CI= 1.003-18.5, p=0.049), fetuína A >673 μ/l (Odds ratio=6.4, 95%CI= 1.47-27.9, p=0.01), e o não uso de estatinas (Odds ratio=5.6, 95%CI= 1.13-28.1, p=0.03). Não foi possível mostrar associações com os marcadores da remodelação óssea ou com os parâmetros achados de histomorfometria tanto no diagnostico como na progressão da CV. Conclusão: O presente... / Abstract: Cardiovascular disease is the main cause of death in patients with chronic kidney disease (CKD) in hemodialysis and vascular calcification (VC) is common in this population. The main objective of this study was to evaluate the association of markers of mineral and disorder on the presence and progression of VC in a cohort of dialysis patients. Secondarily, it was intended to identify associations between clinical, laboratory and body composition markers with the presence and progression of VC. There were included patients aged over 18 years on chronic dialysis for more than 90 days. The patients were submitted to bone biopsy at the beginning of the follow-up and histomorphometric data analyzed. To investigate VC a sum of radiological scores of Kauppila and Adragão were obtained in two occasions: at the beginning of the follow-up and after 12 months. In addition, clinical, hormonal, inflammatory, biochemical and nutritional evaluation were performed. Results: Sixty patients completed the study; 41.7% were female, 43.4% diabetics, and the average age was 56.7 years (range 25 to 89 years). At the beginning of the follow-up, 75% of the patients showed VC and its progression was observed in 56.8%. At multivariate analysis, age > 60 years (Odds ratio = 50.2, 95% CI=4.1-618.4, p=0.002), FGF23>3000 Ru/mL (Odds ratio = 5.7, 95% CI=1.00-329, p=0.05), and fetuin A>673 g/l (Odds ratio = 7.34, 95% CI=1.26-43.7, p=0.03) were associated with VC. As for the VC progression, the association was shown to age>60 years old (Odds ratio = 4.3, 95% CI=1.003-18.5, p=0.049), fetuin A> 673 g/l (Odds ratio = 6.4, 95% CI = 1.47-27.9, p=0.01), and the non-use of statins (Odds ratio = 5.6, 95% CI=1.13-28.1, p=0.03). It was not possible to show the association with bone turnover markers and the histomorphometric findings both in diagnosis and progression of VC. In conclusion, the present study reinforces the role of aging, the FGF23 level and the statin protection in ... / Doutor

PET imaging, using the bone tracer Na18F, allows the non-invasive location of atherosclerotic plaques that are at risk of rupture. However, the spatial resolution of PET is only 4-5 mm, limiting the mechanistic information this technique can provide. In this thesis, the use of fluorescence and Raman imaging to elucidate the mechanism of micro-calcification within atherosclerotic plaques has been investigated. A number of fluorescent probes to detect fluoride and calcium have been synthesised. One of the fluoride probes has been shown to be selective for fluoride however, the concentration of fluoride required to activate the probe is order of magnitudes higher than the amount of Na18F used for PET imaging making it problematic to use for future studies. On the other hand, a calcium probe has been shown to: selectively bind to hydroxyapatite (HAP); permit visualisation and quantification of HAP in both vascular and bone cell models; and effectively stain cultured aortic sections and whole mouse aorta for OPT imaging. Building on these preliminary data, fluorescence imaging and immunohistochemistry (IHC) imaging of both healthy and atherosclerotic tissue that were previously subjected to PET imaging, were successfully carried out showing the ability of the probe to detect HAP in human vascular tissue. IHC staining for Osteoprotegerin (OPG) and Osteopontin (OPN), two bone proteins recently detected in vascular tissue, showed the co-localization of OPG with the probe. Conversely, the OPN was shown to localize in areas surrounding high OPG and probe signal. To determine the exact composition of vascular calcification, Raman spectroscopy was also used. It is believed that the biosynthetic pathway to HAP passes through a series of transitional states; each of these has different structural characteristics which can be studied using Raman spectroscopy. In particular, HAP has a strong characteristic Raman peak at 960 cm-1. An increase in HAP concentration has been detected by Raman in both calcified cell models and aortic sections. When human vascular tissue was analysed, an additional peak at 973 cm-1 was present suggesting the presence of whitlockite (WTK) in this tissue as well as HAP.

BACKGROUND: Calcific aortic valve disease (CAVD) is the most prevalent heart valve disease in the developed world, claiming almost 17,000 deaths annually in the United States. The lack of noninvasive therapeutics to slow or halt the disease warrants the need for further understanding of the pathobiological mechanisms of CAVD. A tri-laminar structure of aortic valve determines the biomechanical properties of its leaflets. Valvular endothelial cells (VECs) and interstitial cells (VICs) are responsible for valve structural integrity. Traditional two-dimensional culture conditions spontaneously activate the pathological differentiation of VICs making in vitro studies challenging. A monolayered three-dimensional (3D) hydrogel platform was recently developed as a novel in vitro culture system to study the phenotypic changes of VICs leading to microcalcification (early stages of calcification). This system, however, did not fully recapitulate the microenvironment of native valve tissues because of the lack of individual layer representations and endothelial coverage. Bioprinting technology, which allows precise and integrated positioning of cells, matrix, and biomolecules, may provide an innovative approach toward building a more biologically relevant 3D culture platform. OBJECTIVE: This study aims to lay the groundwork for building a multilayered 3D-bioprinted culture platform to study CAVD by first validating the use of bioprinting in monolayered cell-laden 3D hydrogel constructs. METHODS: Human VICs were isolated from patients undergoing valve replacement surgeries at Brigham and Women’s Hospital (Boston, MA) according to Institutional Review Board (IRB) protocols. VICs were expanded in culture medium containing growth factors for up to 6 passages and then encapsulated in hydrogels using 3D bioprinting technology. After encapsulation, VIC-laden 3D constructs were cultured in either normal or osteogenic conditions for 21 days. Microcalcification, cell proliferation, and cell apoptosis were evaluated using fluorescent staining and confocal microscopy. Results were compared with results from VIC-laden hydrogels made manually. RESULTS: An increase in microcalcification was observed throughout bioprinted VIC-laden hydrogel constructs cultured in osteogenic conditions for 21 days, whereas normal conditions developed negligible calcification signals. Cell proliferation and apoptosis were not significantly different between normal and osteogenic groups in bioprinted hydrogels. Cell-free hydrogels did not exhibit any microcalcification. Overall, bioprinted hydrogels showed less nonspecific background staining than handmade hydrogels, thus providing a better means for quantitative assessments of 3D culture platforms. CONCLUSION: Based on bioprinting technology, an improved monolayered cell-laden hydrogel platform was successfully established as a first step toward building an in vitro multilayered disease model for studying the pathobiological mechanisms of CAVD. The results in this study were consistent with current literature that proposes calcification as a cell-dependent, apoptotic-independent, and proliferation-independent pathway. / 2019-07-13T00:00:00Z

O objetivo deste trabalho foi avaliar a associação de calcificação da aorta abdominal (CAA) com marcadores do metabolismo ósseo: densidade mineral óssea (DMO), dados laboratoriais (cálcio, fósforo, 25OH-vitamina D, PTH) e clínicos em uma população brasileira de idosos. Este foi um estudo de corte transversal onde foram incluídos 815 indivíduos com idade igual ou superior a 65 anos. Os dados demográficos e de estilo de vida, bem como os parâmetros clínicos que identificam os fatores de risco para osteoporose e calcificação vascular foram obtidos por um questionário padronizado. Densidade mineral óssea (DMO) e parâmetros laboratoriais foram avaliados em todos os indivíduos. Foram realizadas radiografias de coluna lombar para a análise de calcificação da aorta abdominal nos segmentos correspondentes às vértebras L1 a L4. Para cada segmento lombar foi dada uma pontuação de 0-3 para as paredes anterior e posterior, com um escore máximo de 24 pontos (Kaupilla et al., 1997). Resultados: 63,2% dos idosos apresentavam algum grau de CAA, com um escore médio de 4,68 5,88. Analisando as variáveis contínuas observamos que o escore de CAA foi correlacionado diretamente à idade, fósforo sérico, LDL-colesterol (LDL-C), triglicérides e inversamente ao índice de massa corpórea (IMC), DMO do colo do fêmur e DMO do fêmur total (p<0,05). Em relação às variáveis binárias o escore de CAA foi associado à história de fraturas prévias por fragilidade, baixa atividade física, quedas no último ano, tabagismo atual e hipertensão arterial (p<0,05). A análise de regressão linear múltipla demonstrou que o escore de CAA foi diretamente relacionado à idade (p<0,001), tabagismo atual (p<0,001), hipertensão arterial (p=0,002), LDL-C (p=0,05), triglicérides (p=0,002), fósforo sérico (p=0,005) e inversamente associado à DMO de fêmur total (p<0,001). Um aumento no escore de CAA foi observado com a elevação dos níveis séricos de fósforo [ 2,4mg/dL: escore de CAA = 1,9 (DP: 3,9); 2,5-3,5mg/dL: escore de CAA = 4,5 (DP: 5,6) e > 3,5mg/dL : escore de CAA = 5,3 (SD: 6,3) p=0,003]. Este estudo demonstrou que, além dos fatores de risco clássicos para doença cardiovascular (HAS, tabagismo e lípides), o fósforo sérico e a DMO do fêmur total foram fatores de risco adicionais ao complexo processo de calcificação vascular em idosos da comunidade / The aim of this study was to analyze abdominal aortic calcification (AAC) and its possible association with bone mineral density (BMD) as well as the clinical and laboratory data. This was a cross-sectional study conducted between 2005 to 2007, with a population-based sample of older men and women living in Brazil. Eight hundred and fifteen subjects 65 years old were studied. The risk factors for osteoporosis and cardiovascular disease, demographic data and lifestyle characteristics were collected using a standardized questionnaire. BMD was measured by DXA. Kauppilas method was used to quantify the AAC score (AACS) by spine X-rays. Laboratory analyses were also performed. AAC was observed in 63.2% of subjects with a mean AACS of 4.68 (5.88). AACS was directly correlated with age, phosphorus, LDL-cholesterol, triglycerides, and inversely correlated with body mass index, femoral neck BMD and total femur BMD (p<0.05). Regarding binary variables, the AACS was associated with previous fragility fractures, current smoking, low physical activity, falls and arterial hypertension (p<0.05). Multiple linear regression analysis demonstrated that the AACS was positively associated with age (p<0.001), current smoking (p<0.001), arterial hypertension (p=0.002), LDL-C (p=0.05), triglycerides (p=0.002), phosphate (p=0.005) and negatively associated with total femur BMD (p<0.001). An increased of AACS was observed with the elevation of serum phosphorus levels [ 2.4mg/dL: AACS=1.9 (SD:3.9); 2.5-3.5mg/dL: AACS=4.5 (SD:5.6) and > 3.5mg/dL: AACS=5.3 (SD:6.3), p=0.003]. Our study identified serum phosphate and hip BMD as additional players in the complex process of vascular calcification outside the setting of kidney failure in community-dwelling older population and extended the previous observations of well-known risk factors for cardiovascular disease

Historically, Archaias angulatus has been a major contributor to foraminiferal assemblages and sediments in coral-reef environments throughout the Caribbean and tropical Atlantic. A variety of anomalous features were observed in the tests of A. angulatus individuals collected live from the Florida reef tract in 2004 and 2005. Six types of anomalies were documented using scanning electron microscopy: microborings, microbial biofilm, pitted surfaces, dissolution, calcification abnormalities, and growth abnormalities. Calcification abnormalities included mineralogical projections, lacy crusts, and repair marks. These abnormalities were found among both juvenile and adult A. angulatus, and similar features were also found among Cyclorbiculina compressa and Laevipeneroplis proteus specimens collected live in the same samples. In 2006, a comprehensive study was undertaken to see if the occurrence and types of morphological abnormalities have changed in A. angulatus from the Florida Keys over the past 2.5 decades. Archived samples of A. angulatus collected in 1982-83 from John Pennekamp Coral Reef State Park were compared to recent samples. Seven different types of morphological abnormalities and 5 different surface texture anomalies were documented. Eighty-six combinations of abnormalities and surface textures were observed. Physical abnormalities included profoundly deformed, curled, asymmetrical, and uncoiled tests, irregular suture lines, surface "blips," and breakage and repair. Surface texture anomalies included surface pits, dissolution, microborings, microbial biofilm, and epibiont growth. Epibiont growth included bryzoans, cyanobacteria and foraminifers. The archived samples were not obviously more pristine than the recent samples indicating stress was well underway in the early 1980s. Test strength was compromised in deformed specimens. Crushing strength of abnormal individuals was much more variable compared to individuals with irregular sutures and normal specimens. Deformed individuals also exhibited abnormal test wall structure including dissolution and infilling. Mg/Ca ratios for normal and deformed specimens were within normal parameters (12-15 µmol/mol). Implications of these observations are at least twofold. First, in studies of fossil assemblages, damage to tests and changes in test-surface textures should not be assumed to have occurred postmortem, and may provide evidence of environmental stressors acting upon living populations. In addition, we speculate that test dissolution in larger miliolid foraminifers when alive can indicate declining carbonate saturation in seawater, which can result locally from salinity changes or increasing benthic respiration rates, as well as globally from rising concentration of atmospheric CO2.

Includes bibliographical references (leaves 226-273.) Investigates the regulation of the expression of CYP27B1, CYP24 and vitamin D receptor (VDR) mRNA, both in the bone and in the kidney, with the aim to determine whether the regulation of the vitamin D metabolism in the bone is independent from that in the kidney. The effects of age, dietary calcium and vitamin D status on the expression of these genes in both the kidney and the bone, as well as on a number of biochemical factors known to regulate the renal metabolism of 1,25D, such as PTH, calcium and 1,25D itself, were examined. CYP27B1 mRNA expression was also studied in histological sections of rat femoral bone.