L'insuffisance rénale chronique (IRC) demeure un problème de santé publique du fait de l'augmentation de sa prévalence. Malgré l'amélioration de la prise en charge, le taux de mortalité reste plus élevé comparé à la population générale. Parmi les causes de décès, les maladies cardiovasculaires, d'origine multifactorielle (élargissement et hypertrophie des artères, athérosclérose, calcifications vasculaires et valvulaires) sont au premier plan. A côté des facteurs de risque classiques, des facteurs non traditionnels, liés aux perturbations métaboliques de l'IRC, ont été mis en évidence, comme l'inflammation, la malnutrition, le stress oxydant, les anomalies du métabolisme minéralo-osseux. La meilleure connaissance de la physiopathologie de la vasculopathie de l'IRC permet d'émerger de nouveaux biomarqueurs pour stratifier le risque cardiovasculaire chez l'IRC.OBJECTIFS-METHODOLOGIE GENERALE : Nous avons réalisé une approche biochimique pour explorer trois composantes du risque cardiovasculaire chez l'IRC : stress oxydant, perturbations qualitatives des HDL (high-density lipoprotein) et métabolisme minéralo-osseux.RESULTATS : Dans une première publication la production d'anion superoxyde a été évaluée, via une méthode de chemoluminescence, en fonction du stade de l'IRC. Alors que la surproduction de formes réactives de l'oxygène est bien connue au stade 5d et peut être liée à la procédure dialytique, il existe peu de données aux stades précoces. Notre étude a porté sur 136 patients IRC non dialysés des stades 1à 5. Les résultats montrent que la production de FRO est assurée aux stades 4 et 5. Un bas débit de filtration glomérulaire (MDRD<30ml/min/1.73m2), l'inflammation (fibrinogène >3.7g/l) et des taux anormaux d' HDL (<1.42mM et >1.75mM) apparaissent comme les principaux déterminants du stress oxydant chez l'IRC non dialysé.Alors que dans la population générale, un taux bas de HDL est reconnu comme un facteur de risque important, nous avons montré (publication 1) que des taux anormaux de HDL, bas comme hauts, étaient indépendamment associés au stress oxydant chez les sujets IRC. Dans une deuxième publication, nous avons précisé la composition des HDL en se basant sur d'éventuelles modifications qualitatives des protéines associées à la structure des lipoprotéines. Une étude protéomique a été réalisée chez 7 patients hémodialysés versus 7 sujets sains. Nous avons retrouvé 40 protéines exprimées différemment sur les 122 identifiées, dont l'apoCII, l'apoCIII qui sont significativement augmentées et la transferrine abaissée. Ces protéines interviennent dans de nombreuses fonctions comme la réponse inflammatoire, l'activation du complément, la régulation de l'oxydation des lipoprotéines, l'homéostasie des cations.Dans une troisième publication, l'épuration du FGF23, phosphatonine impliquée dans les anomalies du métabolisme minéralo-osseux, été étudiée chez l'hémodialysé chronique en fonction de la techniques de dialyse (hémodialyse (HD) high flux versus hémodiafiltration on line (OL-HDF)). Notre étude a porté sur 53 patients dans le groupe HD et 32 patients dans le groupe OL-HDF. Dans les deux groupes le taux de FGF23 en post-dialyse est significativement plus bas qu'en pré-dialyse. Cependant, le taux de réduction, la clairance et le KT/V du FGF23 sont significativement plus bas dans le groupe OL-HDF.CONCLUSION-PERSPECTIVES : Chez l'IRC, avec l'appariation de facteurs de risque non traditionnels, de nouveaux biomarqueurs ont émergés dans la stratification du risque cardio-vasculaire. Ces biomarqueurs peuvent devenir des bioacteurs et représenter de nouvelles cibles d'action et de prévention de l'atteinte cardio-vasculaire chez l'IRC. La complexité des mécanismes physiopathologiques impliqués, nous incite à proposer des approches multimarqueurs. Actuellement des études biocliniques se poursuivent en mettant en place des cohortes régionales de patients aux stades 1 à 5 et de patients incidents en dialyse. / BACKGROUND: Chronic kidney disease (CKD) is a public health problem because of its increasing prevalence. Despite care improvements, the mortality rate remains higher compared to general population. Among causes of death, cardiovascular diseases with multifactorial origins (enlargement and hypertrophy of arteries, atherosclerosis, vascular and valvular calcifications) are in the foreground. Besides the traditional risk factors, non-traditional factors associated with metabolic disorders in CKD were bring out, such as inflammation, malnutrition, oxidative stress, mineral and bone disorder. A better knowledge of vasculopathy physiopathology in CKD allows the emergence of new biomarkers to stratify cardiovascular risk in CKD.AIMS-METHODOLOGY: We performed a biochemical approach to explore three components of cardiovascular risk in CKD: oxidative stress, qualitative alterations of HDL (high-density lipoprotein) and mineral and bone disorder.RESULTS: In a first publication, the superoxide anion production, according to the stage of CKD, was assessed using a chemiluminescence method. While the overproduction of reactive oxygen species is well known at the 5d stage of CKD and may be related to the dialysis procedure, there are few data in the early stages. Our study included 136 non-dialysis patients at stages 1 to 5 of CKD. Results showed an enhanced superoxide production at the pre-dialysis phase, stages 4 and 5 of CKD. Reduced glomerular filtration rate (MDRD <30 ml / min / 1.73m2), inflammation (fibrinogène≥3.7g / l) and abnormal levels of HDL (<1.42mM and ≥1.75mM) appears as main determinants of oxidative stress in non-dialysis CKD patients.While in general population, a low HDL rate is recognized as an important risk factor, we showed (publication 1) that abnormal levels of HDL, low as high, were independently associated with oxidative stress in CKD subjects. In a second publication, we have defined the HDL composition based on qualitative changes in the structure of proteins associated with lipoproteins. A proteomic study was performed in 7 patients on hemodialysis versus 7 healthy subjects. We found 40 proteins differently expressed on the 122 identified, including apoCII, apoCIII which are significantly increased and transferrin lowered. These proteins are involved in many functions such as inflammatory response, complement activation, regulation of lipoprotein oxidation and homeostasis cations. In a third publication, the removal of FGF23, phosphatonin involved in mineral and bone metabolism, was studied in chronic hemodialysis according to the dialysis techniques (high flux hemodialysis (HD) versus on line hemodiafiltration (OL- HDF)). Our study included 53 patients in the HD group and 32 patients in the OL-HDF group. In both groups the rate of FGF23 in post-dialysis was significantly lower than in pre-dialysis. However, rate of reduction, clearance and KT / V of FGF23 were significantly lower in the OL-HDF group.CONCLUSION-PROSPECTS: In the IRC, with the appearance of non traditional risk-factors, new biomarkers have emerged in the stratification of cardiovascular risk. These biomarkers can become bioactors and represent novel targets of action and prevention in the cardiovascular disease in CKD. The complexity of the involved physiopatholological mechanisms, leads us to propose multimarkers approaches. Currently bioclinical studies continue with the constitution of regional cohorts of patients at stages 1 to 5 of CKD and incident dialysis.

Chez les patients souffrant d'insuffisance rénale chronique, les calcifications vasculaires représentent la première cause de mortalité. Elles résultent de la trans-différenciation des cellules musculaires lisses (CMLs) en cellules de type ostéoblastique et/ou chondrocytaire, en réponse à des cytokines inflammatoires ou à une hyperphosphatémie. Les CMLs forment alors des cristaux par l'activité de la phosphatase alcaline non-spécifique du tissu (TNAP). A la lumière de résultats récents, nous avons émis l'hypothèse que la TNAP module la trans différenciation des CMLs. Nos objectifs étaient donc de déterminer l'effet de la TNAP dans la trans-différenciation des CMLs, et d'étudier les mécanismes impliqués dans son induction, avec un intérêt particulier pour les microRNAs. Nous avons observé que l'ajout de phosphatase alcaline purifiée ou la surexpression de TNAP stimule l'expression de marqueurs chondrocytaires en culture de CMLs et de cellules souches mésenchymateuses. De plus, l'inhibition de la TNAP bloque la maturation de chondrocytes primaires. Nous excluons un rôle des cristaux formés par la TNAP, puisque l'ajout de cristaux seuls ou associés à une matrice collagénique n'a pas reproduit les effets de la TNAP. Nous suspectons que la TNAP agit en hydrolysant le pyrophosphate inorganique (PPi). En effet, c'est la TNAP qui hydrolyse le PPi en culture de CMLs et de chondrocytes, et le PPi mime les effets de l'inhibition de TNAP en culture de chondrocytes. Enfin, nous rapportons le profil de microRNA des artères cultivées en conditions hyperphosphatémiques. Ces résultats pourraient être particulièrement importants dans le développement de nouvelles approches thérapeutiques / In patients with chronic kidney disease (CKD), vascular calcification represents the main cause of mortality. Vascular calcification results from the trans-differentiation of vascular smooth muscle cells (VSMCs) into cells similar to osteoblasts and/or chondrocytes, in response to inflammatory cytokines or hyperphosphatemia. Calcifying VSMCs form calcium phosphate crystals through the activity of tissue nonspecific alkaline phosphatase (TNAP). In light of recent findings, we hypothesized that TNAP also modulates VSMC trans-differentiation. Our objectives were therefore to determine the effect of TNAP activity on VSMC trans-differentiation, and secondly to investigate the molecular mechanisms involved in TNAP expression in aortas, with a particular interest in microRNAs. We first observed that addition of purified alkaline phosphatase or TNAP over-expression stimulates the expression of chondrocyte markers in culture of the mouse and rat VSMC lines, and of mesenchymal stem cells. Moreover, TNAP inhibition blocks the maturation of mouse primary chondrocytes and reduces mineralization. We exclude a role for crystals in TNAP effects, since addition of crystals alone or associated to a collagenous matrix fails to mimic TNAP effects. We rather suspect that TNAP acts through the hydrolysis of inorganic pyrophosphate (PPi). Indeed, PPi is hydrolyzed by TNAP in VSMCs and chondrocytes and addition of PPi mimics the effects of TNAP inhibition on chondrocyte maturation. Finally, we report microRNA signature of aortic explants treated under hyperphosphatemic conditions that induce vascular calcification. These results could be of particular importance in patients with CKD

La calcification vasculaire est l’accumulation de cristaux de calcium dans les vaisseaux sanguins à travers un processus pathologique qui ressemble à la formation de l’os ou du cartilage. Elle apparaît notamment chez les patients diabétiques ou atteints d’une insuffisance rénale chronique. La conséquence principale de la calcification vasculaire est la perte de l’élasticité qui est indispensable pour la fonction des larges artères, elle est de plus associée à la mortalité des patients hémodialysés. Les traitements contre la calcification vasculaire sont généralement limités à ceux qui corrigent les facteurs causatifs des problèmes de santé mais aucune intervention efficace, spécifique et ciblée n’est disponible. Par conséquence, une compréhension profonde des mécanismes moléculaires impliqués dans la calcification vasculaire est nécessaire dans le but de trouver de nouvelles cibles thérapeutiques. La phospholipase D catalyse l’hydrolyse des phospholipides en acide phosphatidique et une tête polaire, elle est aussi impliquée dans différentes fonctions cellulaires et maladies. Il a été démontré qu’elle peut être activée par des facteurs impliqués dans l’ostéogenèse et par d’autres impliqués dans la calcification vasculaire. Ainsi, nous avons étudié le rôle de la phospholipase D dans la calcification vasculaire dans 3 modèles différents. Le premier est un modèle in-vitro de cellules musculaires lisses murines (lignée cellulaire MOVAS), elles sont cultivées en présence d’acide ascorbique et de β-glycérophosphate. Le deuxième est un modèle ex-vivo d’explants d’aortes cultivés en présence de fortes concentrations de phosphate et le troisième est un modèle in-vivo d’insuffisance rénale chronique produite chez des rats. Dans ce dernier modèle, la calcification vasculaire est induite par un régime riche en phosphore et en calcium et par des injections de vitamine D active. La calcification dans ces trois modèles a été suivie par l’analyse de la minéralisation en dosant les dépôts de calcium, de l’activité phosphatase alcaline, et de l’expression de différents marqueurs ostéo-chondrocytaires. Une augmentation de l’expression génique de Pld1 a été observée dans les trois modèles, en particulier au cours des premières étapes de la calcification, et a été accompagnée d'une activité accrue de la phospholipase D dans les modèles in vitro et ex-vivo. L’inhibition de l’activité phospholipase D dans ces deux modèles ou de la phospholipase D1 dans le modèle MOVAS a bloqué complètement la calcification. Par contre, l’inhibition spécifique de la phospholipase D2 n’a pas montré des effets significatifs. Deux voies par lesquelles la phospholipase D peut être activée ont été testées, la voie de la protéine kinase C et la voie de la sphingosine-1-phosphate. Ces deux voies métaboliques se sont révélées être impliquées dans le processus de calcification mais pas forcément dans l’activation de la phospholipase D au cours de ce processus. Des résultats préliminaires ont montré que la phospholipase D pourrait agir après activation de la sphingosine kinase 2 dont l’activité s’est avérée nécessaire pour la calcification dans le modèle MOVAS. Des études supplémentaires sont nécessaires pour comprendre par quels mécanismes la phospholipase D est activée et comment elle agit. La phospholipase D pourrait être une nouvelle cible thérapeutique pour le traitement de la calcification vasculaire vu que son inhibition ne semble pas avoir des effets secondaires chez les patients / Vascular calcification is the accumulation of calcium phosphate crystals in blood vessels via a pathological process that resembles physiological bone or cartilage formation. Calcification in the medial layer is mainly seen in diabetic and chronic kidney disease patients. Its main consequence is the loss of elasticity which is indispensable for the function of large arteries. Accordingly, vascular medial calcification was significantly associated with mortality in hemodialysis patients. Vascular calcification treatments are limited to those that correct its causative health problems, but no efficient, specific and targeted interventions are available. Therefore, a deep understanding of its molecular mechanisms is needed to find novel therapeutic targets. Phospholipase D catalyses the hydrolysis of phospholipids into phosphatidic acid and a head group. It is implicated in different cellular functions and diseases. It was found to be activated by factors involved in osteogenesis and others involved in vascular calcification. Thus, we investigated its role in vascular calcification in 3 models: an in-vitro model of murine smooth muscle cell line MOVAS cultured with ascorbic acid and β-glycerophosphate, an ex-vivo model of rat aortas cultured in high phosphate medium, and an in-vivo model of adenine-induced kidney disease in rats in which vascular calcification is induced by further administration of high phosphorus/calcium diet and active vitamin D injections. Calcification was detected in these models using different approaches including alkaline phosphatase activity, calcium dosage, and/or evaluation of osteo-chondrocytic markers expression. Pld1 expression was seen upregulated in all the three models, especially during early stages of calcification, and was accompanied with increased phospholipase D activity in the in-vitro and ex-vivo model. The inhibition of total phospholipase D activity in these two models, or that of phospholipase D1 in case of MOVAS model, abolished calcification. Phospholipase D2-specific inhibition did not induce significant effects. Two pathways by which phospholipase D can be activated were tested, protein kinase C and sphingosine 1-phosphate pathways, but they were found to be involved in calcification but not necessary for phospholipase D activation during this process. Alternatively, the preliminary results showed that PLD may be acting by activation of sphingosine kinase 2 whose activity was found necessary for calcification in the MOVAS model. Further investigations are needed to understand the mechanisms by which phospholipase D is activated and by which it is acting. Phospholipase D could be a novel target for vascular calcification especially that its inhibition in patients did not induce adverse health effects

INTRODUÇÃO: Os níveis séricos de fósforo (P) têm sido associados a doenças cardiovasculares e mortalidade em pacientes com doença renal crônica e na população geral. Estudos in vitro demonstram que altas concentrações de fósforo extracellular são capazes de induzir calcificação vascular e disfunção endotelial. O Fibroblast Growth Factor 23 (FGF-23) é um hormônio fosfatúrico e foi relacionado à presença de aterosclerose em pacientes idosos. OBJETIVO: O objetivo deste estudo foi investigar as relações entre P, FGF-23 e outros atores do metabolismo mineral e a ocorrência de doença arterial coronariana em pacientes com função renal preservada. MÉTODOS: Duzentos e noventa pacientes clinicamente estáveis com indicação de cineangiocoronariografia eletiva e clearance de creatinina superior a 60 ml/min/1.73 m2 foram submetidos à Tomografia Computadorizada Multislice para avaliação da calcificação coronariana e coleta de sangue para dosagens bioquímicas. A calcificação coronariana foi quantificada através do Escore de Agatston (EA) e os Escores de Friesinger e Gensini foram calculados para quantificar a obstrução coronariana. RESULTADOS: A média de idade dos pacientes foi 58,1± 9,3 anos, 81% eram hipertensos e 35,5% diabéticos. Os pacientes foram divididos em grupos de acordo com o EA utilizando-se como ponto de corte o valor de 10 Unidades Hounsfield (HU). O P sérico foi maior no grupo de pacientes com EA > 10 HU (3,63 0,55 vs 3,49 0,52mg/dL; p=0,019). Cada 1 mg/dL de elevação no P sérico associou-se a um aumento de 92% no risco de apresentar o EA > 10HU [Odds Ratio (OR) =1,92, CI 1,56-3,19; p=0,01]. Quando os pacientes foram divididos de acordo com a mediana do Escore de Friesinger (4 pontos), o grupo com valores superiores à mediana apresentou P sérico maior (3,6 0,5 vs. 3,5 0,6 mg/dl; p=0,04) e FGF-23 menor (mediana 40,3 pg/mL intervalo interquartil 24,1-62,2 vs. 45,7 pg/mL intervalo interquartil 31,7-76,1; p=0,01) quando comparado àquele com valores menores ou iguais a 4. Pacientes no tercil mais alto do escore de Gensini também apresentaram P sérico mais elevado que os demais (p<0,05). Nas análises de regressão logística uni e multivariadas, cada 1 mg/dL de elevação no P sérico implicou em um aumento de 74% no risco de apresentar o Escore de Friesinger superior à mediana (OR 1,74, CI 1,06- 2,88; p=0,03) e o FGF-23 sérico foi preditor negativo do Escore de Friesinger (OR 0,26, CI 0,11-0,63; p=0,002) Os níveis séricos de cálcio e paratormônio não mostraram associação com a presença de doença coronariana. CONCLUSÃO: Em pacientes com suspeita de doença arterial coronariana e função renal preservada, o fósforo sérico foi preditor da presença de calcificação e obstrução coronariana e houve uma associação negativa entre o FGF-23 sérico e a presença de obstrução coronariana. / INTRODUCTION: Serum phosphorus (P) has been associated with cardiovascular diseases and mortality in chronic kidney disease patients and in the general population. In vitro studies suggest that excessive phosphorus induces vascular calcification and endothelial dysfunction. Fibroblast growth factor 23 (FGF-23) is a phosphaturic hormone and has been correlated to atherosclerosis in the community. AIM: This study intended to investigate the associations between P, FGF-23 and other mineral metabolism players and coronary artery disease in patients with preserved renal function. METHODS: Two-hundred ninety patients with a creatinine clearance higher than 60ml/min/1,73m2 undergoing elective coronary angiography were submitted to Multislice Computed Tomography in order to evaluate coronary calcification and blood was collected for biochemical analyses. Coronary artery calcification was quantified using the Agatston Score (AS). Friesinger (FS) and Gensini Scores (GS) were calcutalet to quantify coronary obstruction. RESULTS: Considering the whole population, mean age was 58.1±9.3 anos, 81% were hypertensive and 35.5% were diabetics. Patients were divided according to AS using the value of 10 Hounsfield Units (HU) as the cutoff.point. Serum phosphorus was higher in patients with an AS > 10HU when compared to the group with an AS 10 HU (3.63 0.55 vs 3.49 0.52mg/dL, p=0.019). Each 1 mg/dL of elevation in the serum phosphorus implied a 92% additional risk of presenting an AS > 10 HU [Odds Ratio (OR) =1.92, CI 1.56-3.19; p=0.01]. Patients were also divided using the median Friesinger score (4 points) as the cutoff value. Serum phosphorus was higher (3.6 0.5 vs. 3.5 0.6 mg/dl, p=0.04) and intact FGF-23 was lower (median 40.3 interquartile range 24.1-62.2 pg/mL vs. 45.7 interquartile range 31.7- 76.1 pg/mL, p=0.01) in the FS > 4 group. Patientis in the higher Gensini Score tertile presented elevated serum phosphorus when compared to the other groups (p<0,05). In the uni and multivariate logistic regression analyses, a rise of 1 mg/dL of serum phosphorus carried a 74% increase in the risk of having a FS higher than 4 (OR 1.74, CI 1.06-2.88; p=0.03) and FGF-23 was a negative predictor of FS (OR 0.26, CI 0.11-0.63; p=0.002). Serum calcium and parathormone were not associated with the presence of coronary artery disease. CONCLUSIONS: In patients with suspected coronary artery disease and preserved renal function, phosphorus was predictive of both coronary artery calcification and obstruction. There was a negative association between FGF-23 and coronary obstruction

O hiperparatireoidismo secundário à doença renal crônica (HPS) acomete inúmeros pacientes. Não existe consenso sobre qual tipo de paratireoidectomia (PTx) se associa com melhores resultados. Na PTx total com autoimplante (PTx-AI) especula-se se o número de fragmentos implantados melhora desfechos clínicos. Trinta e seis (36) pacientes com HPS foram randomizados para PTx-AI com 45 ou 90 fragmentos de paratireoide. Prospectivamente, avaliamos os fatores clínicos, bioquímicos e anatomopatológicos que influenciaram a função do AI. No início do estudo (t0), o Grupo-45 (N = 28) e Grupo-90 (N = 8) eram semelhantes, com exceção dos níveis séricos de fosfato. Após 12 meses (t12), os níveis séricos de PTH do enxerto e sistêmico correlacionaram-se com o cálcio iônico (Cai)-t0 (r2 = 0,442, p = 0,016; r2= 0,450, p = 0,008, respectivamente). A duração da fome óssea correlacionou-se com fosfatase alcalina (FA)-t0 (r2 = 0,593, p = 0,001). Nas células paratireoideanas, a expressão de PCNA correlacionou-se com o tempo em hemodiálise (r2 = 0,437, p = 0,016); a expressão do receptor-1 do fator de crescimento de fibroblastos (FGFR1) com FA-t0 (r2 = -0,758; p = 0,0001); o receptor de vitamina-D (VDR) com Cai-t0 (r2 = -0,464, p = 0,007) e carga cumulativa de Ca elemento (r2 = - 0,359, p = 0,04); o receptor sensível ao Ca (CaSR) com menor uso de calcitriol (r2 = -0,445, p = 0,049); e o Klotho com a dose de vitamina D pré- PTx (r2 = 0,811, p = 0,027) e com fosfato-t0 (r2= -0,528, p = 0,017). Houve progressão do escore de calcificação vascular [0,53 (0 - 4) vs. 1,1 (0 - 8); p = 0,04], que se correlacionou com a carga cumulativa de Ca elemento (r2 = 0,605, p = 0,006) e com o fosfato-t0 (r2 = 0,503; p = 0,028). Em conclusão, a PTx independentemente do número de AI controlou o HPS; porém parece piorar a calcificação vascular. Os níveis séricos de PTH pós-PTx ou evolução para hipo- ou normoparatireoidismo não foram influenciados pelo número de AI, nem por outros parâmetros bioquímicos e tão pouco pela densidade de expressão de PCNA, CaSR, VDR, FGFR1 ou Klotho nas células paratireoideanas / Hyperparathyroidism secondary to chronic kidney disease (SHP) affects many patients. There is no consensus about what kind of parathyroidectomy (PTx) is associated with better results. In total PTx with auto transplant (PTx- AT) it is speculated that the number of implanted fragments improves clinical outcomes. Third six (36) patients with refractory SHP were randomized to PTx-AT with 45 or 90 parathyroid fragments. We prospectively evaluated the clinical, biochemical and pathological factors influencing AT function. At baseline (t0) Group-45 (N = 28) and Group-90 (N = 8) were similar, except for serum phosphate levels. After 12 months (t12), PTH levels of graft and systemic correlated with ionic calcium (Cai) t0 (r2 = 0.442, p = 0.016; r2 = 0.450, p = 0.008, respectively). The duration of hungry bone syndrome correlated with alkaline phosphatase (AP) -t0 (r2 = 0.593, p = 0.001). In parathyroid cells, PCNA expression correlated with time on hemodialysis (r2 = 0.437, p = 0.016), expression of receptor-1 of fibroblast growth factor (FGFR1) with AP-t0 (r2 = -0.758; p = 0.0001), vitamin D receptor (VDR) with Cai t0 (r2 = -0.464, p = 0.007) and cumulative elemental Ca load (r2 = -0.359, p = 0.04), Ca sensing receptor (CaSR) with less use of calcitriol (r2 = -0.445, p = 0.049), and Klotho with the dose of vitamin D pre-PTx (r2 = 0.811, p = 0.027) and phophate-t0 (r2 = -0.528, p = 0.017). There was progression of vascular calcification score [0.53 (0 to 4) vs. 1.1 (0 to 8); p = 0.04] which correlated with cumulative elemental Ca load (r2 = 0.605, p = 0.006) and with phosphate-t0 (r2 = 0.503; p = 0.028). In conclusion, PTx controlled refractory SHP regardless of the number of AT; however, it seems to worsening vascular calcification. Serum levels of PTH or post-PTx evolution of hypo- or normoparathyroidism were not influenced by the number of AT or other biochemical parameters, nor by the density of PCNA expression, CaSR, VDR, FGFR1 or Klotho in parathyroid cells

INTRODUÇÃO: A calcificação vascular (CV) é uma condição comum na doença renal crônica (DRC) e está associada a um maior risco de mortalidade, eventos cardiovasculares e outras comorbidades. A dieta pode ser importante na fisiopatologia da CV e um alvo em potencial para medidas terapêuticas, mas o seu papel ainda não é claro. Assim, o objetivo deste estudo foi avaliar a associação entre o consumo de energia, macro e micronutrientes e CV em pacientes com DRC em tratamento conservador. MÉTODOS: Foram analisados os dados da linha de base de 454 participantes do estudo PROGREDIR. O consumo alimentar foi avaliado por meio de um questionário de frequência alimentar e a ingestão de nutrientes foi ajustada pela energia pelo método dos resíduos. A calcificação arterial coronária (CAC) foi mensurada por tomografia computadorizada sem contraste e apresentada pelo escore de cálcio de Agatston. Após a exclusão dos participantes que utilizavam stent coronário, as análises foram realizadas em 373 pacientes. Inicialmente, considerando-se a distribuição assimétrica da CAC e a não independência entre a ingestão de nutrientes, a associação entre a CAC e o consumo alimentar foi avaliada modelos lineares generalizados mistos. Devido à colinearidade entre os nutrientes, em seguida foi utilizada a regressão de LASSO para identificar os nutrientes mais relacionados à variabilidade da CAC. RESULTADOS: A mediana da idade e da CAC foi de 68 (60, 76) anos e 165 (8, 785), respectivamente. O maior tercil de CAC se associou diretamente à ingestão de fósforo, cálcio e magnésio. Houve um maior consumo de vitamina A, ácido pantotênico e potássio no segundo tercil. Após ajustes para variáveis de confusão (idade, sexo, diabetes mellitus e tabagismo como efeitos fixos e o indivíduo como efeito aleatório), a ingestão de ácido pantotênico (? = 0,48; IC95% 0,22, 0,75; p < 0,001), fósforo (beta = 0,38; IC95% 0,10, 0,65; p = 0,01), cálcio (beta = 0,0008; IC95% 0,0001, 0,0017; p = 0,04) e potássio (beta = 0,0005; IC95% 0,0001, 0,009; p = 0,02) permaneceram associadas à CAC nos modelos lineares generalizados mistos. Devido à colinearidade entre esses nutrientes, foi utilizada a regressão de LASSO para avaliar os nutrientes mais associados à variabilidade da CAC. Nessa abordagem, os nutrientes que mais explicaram a variância da CAC foram o fósforo (beta = 0,25), o cálcio (beta = 0,09) e o potássio (beta = 0,06). CONCLUSÕES: Houve associação entre a CAC e o consumo de fósforo, cálcio e potássio em uma população com DRC. Estudos futuros são necessários para confirmar esses resultados e avaliar o papel de intervenções sobre a prevenção e progressão da CAC baseadas nesses micronutrientes / BACKGROUND: Vascular calcification (VC) is a widespread condition in chronic kidney disease (CKD) and is associated with a higher risk of mortality, cardiovascular events, and other comorbidities. Diet may play an important role in VC and is a potential target for therapeutic measures, but this role is not clear. Thus, the aim of this study was to evaluate the association between energy, macro-and micronutrient intakes and VC in non-dialysis CKD patients. METHODS: We analyzed the baseline data from 454 participants of PROGREDIR study. Dietary intake was evaluated by a validated food frequency questionnaire and nutrient intakes were adjusted for energy by residual method. Coronary artery calcification (CAC) was measured by non-contrast computed tomography and was presented by Agatston calcium score. After exclusion of participants with coronary stent, 373 people remained for the analyses. Initially, taking into account the asymmetrical distribution of CAC and the non-independence between nutrient intakes, we evaluated the association between CAC and dietary intake by generalized linear models and generalized linear mixed models. To address the collinearity between nutrients, we next evaluated the nutrients mostly related to CAC variability by LASSO regression. RESULTS: Median age and CAC were 68 (60, 76) years old and 165 (8, 785), respectively. The highest tertile of CAC was directly associated with the intake of phosphorus, calcium and magnesium. There was a higher intake of vitamin A, pantothenic acid and potassium in the second tertile. After adjustment for confounding variables (age, gender, diabetes mellitus and tobacco use as fixed effects and individual as random effect), the intake of pantothenic acid (? = 0.48; CI95% 0.22, 0.75; p < 0.001), phosphorus (beta = 0.38; CI95% 0.10, 0.65; p = 0.01), calcium (beta = 0.0008; CI95% 0.0001, 0.0017; p = 0.04) and potassium (beta = 0.0005; CI95% 0.0001, 0.009; p = 0.02) remained associated with CAC in the generalized linear mixed models. In order to handle the collinearity between these nutrients, we used the LASSO regression to evaluate the nutrients associated with CAC variability. In this approach, the nutrients that most explained the variance of CAC were phosphorus (beta = 0.25), calcium (beta = 0.09) and potassium (beta = 0.06). CONCLUSIONS: We found an association between CAC and the intake of phosphorus, calcium and potassium in a CKD population. Future studies are needed to confirm these findings and assess the role of interventions on these micronutrients on CAC prevention and progression

As alterações do metabolismo mineral ocorrem precocemente nos pacientes com doença renal e podem interferir na formação, reabsorção e mineralização óssea comprometendo a integridade do esqueleto. Recentemente demonstramos que animais com sobrecarga de fósforo desenvolvem lesões ósseas semelhantes à osteoporose. O controle da hiperfosfatemia se faz com restrição de fósforo na dieta, e com o uso de quelantes. Um dos quelantes mais utilizados são os sais de cálcio. Estudos demonstraram que o uso desses quelantes favorece a progressão de calcificações arteriais nos pacientes com doença renal crônica. O objetivo desse estudo foi avaliar o efeito isolado do cálcio e do cálcio/fósforo no tecido ósseo e cardiovascular de ratos urêmicos submetidos a nefrectomia 5/6 (Nx) e paratireoidectomia (PTX),variando o conteúdo de cálcio e de cálcio/fósforo na dieta desses animais. Os níveis de paratormônio (PTH) foram restaurados com implante de mini-bombas osmóticas para infusão do 1-34 PTH de rato na dose de 0.022 g/100 g/h (fisiológica), ou de veículo (2% cisteina). Imediatamente após a Nefrectomia ou Sham Nx, os animais foram divididos em grupos de acordo com a dieta que continha Ca/P: 0,7%(Grupo Sham), Ca 1,2% (Grupo Nx RCa) e Ca/P: 1,2%/ 1,2% (Grupo Nx RCa/P). Após 2 meses, os animais foram sacrificados e foram realizadas as análises bioquímicas e histomorfométricas. Os animais nefrectomizados desenvolveram doença renal moderada, elevação da pressão arterial, assim como hiperfosfatemia, enquanto que apenas os animais Nx RCa/P cursaram com hipocalcemia. A infusão de 1-34 PTH foi efetiva, e os animais Nx RCa/P cursaram com elevação do FGF 23 e diminuição do calcitriol. Os animais que ingeriram dieta RCa e RCa/P apresentaram diminuição do volume trabecular (BV/TV), com diminuição dos parâmetros de formação(OS/BS e Ob.S/BS). Os animais que ingeriram dieta rica em cálcio e em cálcio/fósforo apresentaram maior apoptose de osteoblastos. A expressão gênica da TRAP foi maior nos animais Nx. Não detectamos calcificação vascular no tecido cardíaco e aorta dos animais. Em conclusão a sobrecarga de cálcio e de cálcio/fósforo associada à infusão fisiológica de PTH levam a diminuição do volume ósseo de animais urêmicos, conseqüente ao aumento da apoptose dos osteoblastos levando menor formação óssea; assim como maior atividade dos osteoclastos avaliada pela TRAP e não promoveu calcificação vascular nestes animais. O modelo animal que utilizamos reflete condições clínicas encontradas em pacientes com DRC / Bone and mineral metabolism disturbances occur early in patients with chronic kidney disease (CKD) and may interfere in bone formation, resorption or mineralization, compromising skeletal integrity. We previously have shown that phosphate (P) overload in uremic rats leads to decreased bone volume. In the clinical setting, the therapy for hyperphosphatemia includes dietary P restriction, as well as P binders, including calcium (Ca) salts. Previous studies have shown that Ca-based P binders favor the progression of vascular calcification in CKD patients. The current study evaluated the isolated effect of Ca or Ca and P overload on bone and cardiovascular tissues from uremic rats that were submitted to 5/6 nephrectomy (Nx) and parathyroidectomy (PTx), manipulating the Ca and P content in their diets. Parathormone (PTH) serum levels were kept in a normal range using miniosmotic pumps delivering rat 1-34 PTH or using vehicle. After Nx, animals were divided into three groups according to the diet: 0.7% Ca, 0.7% P (Sham Group); 1.2% Ca, 0.7% P (Nx HCa Group) and 1.2% Ca, 1.2% P (Nx HCa/P Group). After two months, animals were killed and biochemical and histomorphometric analyses were performed. Nx animals developed moderate CKD, arterial hypertension, as well as hyperphosphatemia, whereas only Nx HCa/P animals showed hypocalcemia. Osmotic infusion of PTH was effective, as confirmed by serum PTH levels. Nx HCa/P animals showed elevated serum FGF 23, as well as decreased serum calcitriol. Animals that were submitted to Ca or Ca/P overload showed decrease trabecular volume and a reduction in bone formation parameters, such as osteoid and osteoblastic surfaces. A significant increase in osteoblast apoptosis was seen in Nx HCa and Nx HCa/P Groups. The TRAP expression was higher in Nx animals. We could not observe vascular calcification in these animals. In conclusion, Ca or Ca/P overload associated with physiologic PTH infusion was associated with lower bone volume in uremic animals, explained by a increased osteoblastic apoptosis leads to decreased bone formation, and increased osteoclastic activity assessed by TRAP. This model resembles clinical conditions that are commonly observed in CKD patients

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-02-26T18:21:33Z No. of bitstreams: 1 barbarabrunaabreudecastro.pdf: 2415695 bytes, checksum: 47789bf55f4ba51557e83055236dab2f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-03-03T14:09:35Z (GMT) No. of bitstreams: 1 barbarabrunaabreudecastro.pdf: 2415695 bytes, checksum: 47789bf55f4ba51557e83055236dab2f (MD5) / Made available in DSpace on 2016-03-03T14:09:35Z (GMT). No. of bitstreams: 1 barbarabrunaabreudecastro.pdf: 2415695 bytes, checksum: 47789bf55f4ba51557e83055236dab2f (MD5) Previous issue date: 2015-08-13 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Introdução: A Doença Renal Crônica (DRC) provoca alterações nas concentrações de fósforo, cálcio, vitamina D e paratormônio. A Quitosana Fe(III) reticulada (QSTFe( III)R) é um quelante de fósforo capaz de reduzir a hiperfosfatemia, principal indutora da calcificação vascular (CV) na DRC. Este polímero derivado da quitina mostrou ação quelante sobre o fósforo in vitro e in vivo em animais não urêmicos. Objetivo: Avaliar a ação quelante de fósforo da QST-Fe(III)R e seu efeito sobre a calcificação vascular em ratos com uremia induzida por adenina. Métodos: Ratos normais e urêmicos induzidos por dieta rica em fósforo (1%) e suplementada com adenina (0,75% - 4 semanas e 0,10% - 3 semanas) foram divididos em 4 grupos e tratados diariamente com água destilada (10ml/Kg/dia); 30mg/Kg/dia de QTSFe( III)R; 500mg/Kg/dia de CaCO3 e 500mg/Kg/dia de Cloridrato de sevelamer (Cl- Sev) durante 4 semanas. Foram mensurados creatinina (Cr), fósforo (P) e cálcio sérico (Ca), fosfatase alcalina (FA), PTH e FGF23, ao final da 4ª e 7ª semanas de experimento. O conteúdo de Ca foi quantificado em fragmentos da aorta abdominal e expresso em mg/g de aorta. Alterações da morfologia vascular foram avaliadas de forma semi-quantitativa no arco da aorta pela coloração de von Kossa. Utilizamos anticorpos específicos para identificação da expressão da angiotensina II (AngioII) e alfa-actina do músculo liso (α-actina) pela técnica de imuno-histoquímica, em fragmentos do arco da aorta. A avaliação morfológica foi realizada apenas na 7ª semana. Resultados: Nos grupos urêmicos observamos redução da função renal com pico de creatinina na quarta semana. Os tratamentos não alteraram a progressão da doença. O grupo DRC apresentou nível de fósforo 35% mais elevado comparado ao grupo controle. Todos os tratamentos reduziram aproximadamente 20% do fósforo sérico, além de reduzirem a fração excretada de fósforo (redução de 20% a 30%). Os tratamentos com QTS-Fe(III)R e CaCO3 foram eficientes em reduzir o PTH e a FA dos animais urêmicos. Acredita-se que o tratamento com Cl-Sev não tenha sido eficiente devido à intercorrências metodológicas de dificuldade de administração da droga. O grupo DRC apresentou conteúdo de cálcio na aorta 80% maior do que o grupo controle e a QTS-Fe(III)R reduziu o conteúdo de cálcio na aorta, apresentando uma média mais baixa que todos os outros tratamentos. Em comparação com o grupo controle, a QTS-Fe(III)R reduziu a expressão de AngioII na camada íntima da aorta. A utilização dos tratamentos não apresentou benefícios sobre a integridade da camada média quando avaliamos a expressão de α-actina. Conclusões: O modelo experimental promoveu perda importante e sustentada de função renal. A QTS-Fe(III)r apresentou eficiência quelante semelhante aos demais já utilizados na prática clínica e reduziu o conteúdo de cálcio na aorta. / Introduction: Chronic Kidney Disease (CKD) causes changes in the concentrations of phosphorus, calcium, vitamin D and parathyroid hormone. Cross-linked Iron(III) Chitosan (QST-Fe(III)R) is a phosphorus binder, with properties of reducing the hyperphosphatemia, the main inducer of vascular calcification (VC) in CKD. This polymer derived from chitin showed chelating action on phosphorus in vitro and in vivo. Objective: To evaluate the phosphorus chelating action of QST-Fe(III)R and its effect on VC in adenine-induced uremic rats. Methods: Normal and uremic rats, induced by adenine feeding (0.75% - 4 weeks and 0.10% - 3 weeks) and phosphorous 1%, were divided into 4 groups and treated daily with distilled water (10ml/kg/day); QST-Fe(III)R 30mg/kg/day; CaCO3 500mg/kg/day and sevelamer hydrochloride (Cl-Sev) 500mg/kg/day, for 4 weeks. Biochemical parameters were measured at the fourth and seventh week: creatinine (Cr), phosphorus (P) and serum calcium (Ca), alkaline phosphatase (FA), PTH and FGF23. The Ca content of the abdominal aortic fragments was quantified and expressed as mg/g of aortic tissue. We evaluated vascular changes in the aortic arch and calcium deposition. Specific antibodies used to identify the expression of angiotensin II (AngioII) and alphasmooth muscle actin (α-actin) by immunohistochemical technique, in fragments of abdominal aorta at seventh week. Results: In uremic groups, we observed reduced kidney function and a maximum creatinine in the fourth week. The treatments did not alter CKD progression. The CKD group showed 35% higher phosphorus, compared to the control group. All treatments reduced approximately in 20% the serum phosphorus, and reduced the FeP (reduction of 20% to 30%). Treatments with QTSFe( III)R and CaCO3 were effective in reducing PTH and FA of uremic rats. We believe that treatment with Cl-Sev has not been effective due to methodological problems during drug administration. The CKD group presented aortic calcium content 80% higher than the control group and the QTS-Fe(III)R reduced the calcium content in the aorta, more than all other treatments. Compared to the control group, the QTS-Fe(III)R promotes the reduction expression of AngioII in aortic intima. The treatments did not show benefits over the media layer integrity when evaluating the α-actin expression. Conclusions: The experimental model showed important and sustained loss of renal function. The QTS-Fe(III)R showed efficiency similar to others phosporus binders already used in clinical practice and reduced the calcium content in the aorta.

Le groupe des KDIGO a défini un nouveau syndrome regroupant les troubles minéraux et osseux et les calcifications vasculaires au cours de la maladie rénale chronique {TMO-MRC). Les TMO-MRC sont associés à une augmentation du risque de fracture, de calcification vasculaire et à une surmortalité. La quête d'un biomarqueur fiable de la maladie osseuse et des calcifications vasculaires reste le défi du néphrologue. Au cours des dernières années, de nombreuses protéines de l'os ont été associées aux calcifications vasculaires chez les patients urémiques, tels que les phosphatases alcalines osseuses et, plus récemment, la sclérostine. Cette petite protéine est secrétée par l'ostéocyte et inhibe l'ostéoformation en bloquant la voie de signalisation Wnt dans l'ostéoblaste. Il a récemment été suggéré que la sclérostine aurait une activité catabolique sur l'os et serait impliquée dans la déminéralisation du squelette. L'objectif de ce travail était d'étudier la sclérostine au cours de la MRC. Nous avons tout d'abord montré que les concentrations sériques de sclérostine augmentaient avec la baisse du débit de filtration glomérulaire mesurée par la clairance de l'inuline et ce dès le stade 3 de la MRC, indépendamment de l'âge. De plus, cette étude nous a permis de montrer pour la première fois que la phosphorémie était indépendamment et positivement associée à la sclérostine sérique. Ensuite, nous avons retrouvé une association positive et forte entre la concentration sérique de sclérostine et les calcifications vasculaires chez des patients en hémodialyse chronique. Enfin, nous avons montré que les calcifications artérielles étaient significativement associées à une qualité osseuse corticale altérée étudiée en scanner quantitatif de haute résolution. Ces résultats suggèrent que la sclérostine pourrait constituer un messager important dans la relation entre l'os et la paroi vasculaire calcifiée des patients atteints d'une insuffisance rénale chronique terminale / The KDlGO group identified a new syndrome involving mineral and bone disorders and vascular calcification in chronic kidney disease (CKD-MBD}. CKD-MBD are associated with an increased risk of fracture, vascular calcification and increased mortality. The search for a reliable biomarker of bone disease and vascular calcification remains the challenge of the nephrologist. ln recent years, many bone proteins have been associated with vascular calcification in uremic patients, such as bone alkaline phosphatase and more recently sclerostin. This small protein is secreted by the osteocyte and is an inhibitor of bone formation by blocking the Wnt signaling in osteoblasts. lt has recently been suggested that sclerostin has a catabolic activity on bone and is involved in the demineralization of the skeleton. The aim of this research was to study the sclerostin during the course of CKD. We first showed that serum levels of sclerostin increased with the decrease of glomerular filtration rate measured by inulin clearance already from stage 3 chronic kidney disease, regardless of age. Furthermore, in this study, we showed for the first time that serum phosphorus was independently and positively associated with serum sclerostin. Subsequently we found a positive and strong association between serum sclerostin and vascular calcification in maintenance hemodialysis patients. Finally, we have shown that arterial calcification were significantly associated with an altered cortical bone quality studied by high resolution peripheral quantitative computed tomography. These results suggest that sclerostin could be an important messenger in the cross-talk between the bone and the calcified vascular wall in end stage renal disease

A gordura pericárdica (GP), um componente do tecido adiposo visceral, tem sido consistentemente relacionada com aterosclerose coronária na população geral. Este estudo avaliou a associação entre GP e a calcificação arterial coronária (CAC) em pacientes com doença renal crônica (DRC) não dialítica. Este é um estudo transversal post-hoc da linha de base de coorte prospectiva de 117 pacientes com DRC em seguimento ambulatorial sem doença coronária manifesta (idade, 56,8 ± 11 anos; 64% do sexo masculino; 95,1% hipertensos; 25,2% diabéticos; 15,5% com história prévia de tabagismo; e estágios 2 a 5 da DRC e ritmo de filtração glomerular estimado de 36,8 ± 18,1 ml/min). O escore de CAC, volume de GP e gordura visceral abdominal (GVA) foram medidos por tomografia computadorizada. A associação da GP, como variável contínua, com a presença de CAC foi analisada por regressão logística multivariada. CAC (escore de cálcio>0) esteve presente em 59,2% dos pacientes. Na comparação com os pacientes sem CAC, aqueles com CAC eram 10 anos mais velhos, apresentaram maior proporção de homens (78,7% versus 42,9%, p < 0.001), tiveram maior circunferência de abdominal (95,9 ± 10,7 versus 90,2 ± 13,2 centímetros, p=0,02), maior volume de GP (224,8 ± 107,6 versus 139,1 ± 85,0 cm³, p < 0,01), e maior área de GVA (109,2 ± 81,5 versus 70,2 ± 62,9 cm², p=0,01). Em análise multivariada ajustada para idade, sexo, diabetes, história de tabagismo, história de tabagismo, e hipertrofia ventricular concêntrica; GP esteve significantemente associada com a presença de CAC (OR: 1,88 95% IC: 1,03-3,43 por desvio padrão, p=0,04). GP permaneceu associada com CAC mesmo após ajuste adicional para ritmo de filtração glomerular e fósforo sérico (OR: 1,85 95% IC: 1,00 - 3,42, p=0,05). A GP está independentemente associada com CAC em pacientes com DRC não dialítica. / Pericardial fat (PF), a component of visceral adipose tissue has been consistently related to coronary atherosclerosis in the general population. This study evaluated the association between PF and coronary artery calcification (CAC) in non-dialysis dependent chronic kidney disease (CKD) patients. This is a post-hoc cross sectional analysis of the baseline of a prospective cohort of 117 outward CKD patients without manifest coronary artery disease (age, 56.9 ± 11.0 years, 64,1% males, 95.1% hypertensive, 25.2% diabetics, 15.5% ever smokers, CKD stage 2 to 5 with estimated glomerular filtration rate 36.8 ± 18.1 ml/min). CAC scores, PF volume and abdominal visceral fat (AVF) areas were measured by computed tomography. The association of PF as a continuous variable with the presence of CAC was analyzed by multivariate logistic regression. CAC (calcium score >0) was present in 59.2% patients. On the comparison with patients with no CAC, those with CAC were 10 years older on average, had a higher proportion of male gender (78.7% vs. 42.9%, p < 0.001), and had higher values of waist circumference (95.9 ± 10.7 versus 90.2 ± 13.2 cm, p=0.02), PF volumes (224.8±107.6 versus 139.1±85.0 cm³, p < 0.01) and AVF areas (109.2 ± 81.5 versus 70.2 ± 62.9 cm², p=0.01). In the multivariate analysis, adjusting for age, gender, diabetes, smoking and, left ventricular concentric hypertrophy, PF was significantly associated with the presence of CAC (OR: 1.88 95% CI: 1.03-3.43 per standard deviation, p=0.04). PF remained associated with CAC even after additional adjustments for estimated glomerular filtration rate or serum phosphorus (OR: 1.85 95% CI: 1.00-3.42, p=0.05). PF is independently associated with CAC in non-dialysis dependent CKD patients