Response of oral calcium overload in patients with high paratormonio and normal ionizado calcium

Foram avaliados 19 pacientes com PTH elevado (3 70 pg/ml) sendo evidenciada hipercalciuria, litiase renal e osteopenia em 14 deles Imagens sugestivas de nodulos hiperfuncionantes das paratireoides foram observadas em apenas 2 pacientes Dez (10) destes 19 pacientes, apresentavam Ca++ serico dentro da faixa de normalidade (normocalcemicos) Em resposta a um teste de sobrecarga oral de calcio, a media de PTH deste grupo normocalcemico foi similar a dos 9 pacientes hipercalcemicos, mas significantemente maior do que a dos controles, tanto aos 60' quanto aos 180' da sobrecarga, apesar da elevacao do Ca++ ter sido semelhante a do grupo controle nestes mesmos periodos' Diferentemente do Ca++, a media de calcio serico total nao se elevou em resposta a sobrecarga de calcio em nenhum dos grupos' Ao se analisar os valores individuais de PTH dos pacientes normocalcemicos, aos 60' e aos 180' da sobrecarga de calcio, observou-se que 4 pacientes reduziram o valor do PTH de maneira similar a dos controles enquanto que nos demais 6 pacientes a reducao foi de menor magnitude do que a dos controles.' A porcentagem de supressao do PTH pos sobrecarga nao diferiu entre os normocalcemicos, hipercalcemicos e controles' Observou-se correlacao negativa e significante entre o PTH e o Ca++ apenas aos 180' no grupo normocalcemico, enquanto o grupo hipercalcemico nao houve relacao...(au)BV UNIFESP: Teses e dissertaçõe

Bone expression of RANKL, osteoprotegerin (OPG) and other cytokines in idiopathic hypercalciuria (IH) patients

Os mecanismos envolvidos na doença óssea da Hipercalciúria Idiopática (HI) ainda permanecem desconhecidos. Citocinas tais como o receptor ativador do fator nuclear NF-kβ (RANK), seu ligante (RANKL) e a osteoprotegerina (OPG), dentre outras, são importantes reguladores da remodelação óssea. Até o momento, não existem estudos demonstrando a expressão óssea destas citocinas na Hipercalciúria Idiopática. O objetivo do presente estudo foi avaliar a expressão óssea de RANKL, OPG, interleucina 1α (IL-1α), fator de crescimento transformador β (TGF-β) e o fator de crescimento fibroblástico (bFGF) em pacientes com litiásicos com HI. Foram realizadas análises imunohistoquímicas de fragmentos ósseos calcificados obtidos de 36 biópsias ósseas previamente realizadas em pacientes litiásicos hipercalciúricos para estudo histomorfométrico no período de 1992 a 2005 nos Serviços de Nefrologia das Universidades Federal e Estadual de São Paulo (UNIFESP e USP). Para efeito de comparação utilizamos um grupo controle que constituiu de tecido ósseo posmortem obtido de 10 indivíduos saudáveis. Na análise histomorfométrica, os pacientes com HI apresentaram uma diminuição do volume ósseo (19,4 ± 7,0 vs 26,2 ± 8,3%, p=0,02), aumento da reabsorção óssea (8,3 ± 5,4 vs 2,6 ± 0,8%, p<0,001) e um aumento no tempo para a mineralização óssea (45,3 ± 31,4 vs 23,0 ± 2,4 dias, p<0,0001) quando comparados ao grupo controle. A imunohistoquímica revelou um aumento da expressão óssea para OPG e RANKL nos pacientes com Hipercalciúria Idiopática comparados aos controles (0,63 ± 0,60 vs 0,14 ± 0,15% e 0,90 ± 1,00 vs 0,27 ± 0,24%, p=0,03, respectivamente) enquanto que para IL-1α não se observou diferença estatística (1,0 ± 1,0 vs 0,7 ± 0,4%). A expressão óssea do RANKL foi significantemente maior em pacientes com HI que apresentaram elevada reabsorção óssea comparada aos com reabsorção óssea normal (1,10 ± 0,99 vs 0,50 ± 0,73%, p=0.03). A expressão óssea para o TGF-β mostrou-se reduzida nos pacientes HI em relação aos controles (0,54 ± 0,7 vs 1,48 ± 1,44%, p<0,003)diferentemente do bFGF que foi similar entre ambos. A expressão óssea do TGF-β se correlacionou diretamente com a superfície e volume osteóides e também com a superfície de mineralização óssea (r=0,36, r=0,50 e r=0,47, p<0,03) nos pacientes com HI. Concluímos que o aumento na expressão óssea do RANKL deve contribuir para a elevação na reabsorção óssea observada nos pacientes com HI. O aumento concomitante da expressão óssea da OPG deve ter sido secundário, na tentativa de antagonizar o efeito estimulante da reabsorção óssea induzida pelo RANKL. O achado da redução da expressão óssea do TGF-β sugere que esta citocina também tenha contribuído para o aumento da reabsorção óssea pela menor inibição do RANKL. Adicionalmente, a menor expressão do TGF-β pode estar relacionada ao retardo na mineralização óssea evidenciada nos pacientes com HI..BV UNIFESP: Teses e dissertaçõe

Osteopontin Function and Interaction with Vascular Calcification and Atherosclerosis

Abstract Vascular calcification is now recognized as a marker of atherosclerotic plaque burden as well as a major contributor to loss of arterial compliance and increased pulse pressure seen with age, diabetes mellitus, and renal failure. Long bones epiphyses serve as a niche of hematopoietic and mesenchymal stem cells contributing for the bone and vascular homeostasis. Hormones and peptides affect the vascular system through activation of different stem cells and transcriptional factors. Recent studies, emphasize the strong correlation between bone matrix that is secreted during bone tissue regeneration and angiogenesis. One of the most important components of bone matrix is osteopontin (OPN) that is linked to the bone regeneration and angiogenesis. OPN serves an adhesive substrate for both vascular smooth muscle (SMCs) and endothelial cells as well a potent chemo tactic factor for SMCs. OPN is present focally in human atherosclerotic coronary and carotid artery specimens but absent in no diseased coronary arteries. OPN mRNA is present in a plaque and mainly expressed in macrophages but also in smooth muscle cell and endothelial cells. Furthermore OPN is correlated with bone turnover and remodeling and may play a role in plaque calcification. The literature reported the expression of bone morphonegic protein 2a, a potent factor for osteoblast differentiation, in human atherosclerosis suggesting that the plaque calcification is an active process. Osteoblasts regulates bone formation, its precursors come from the mesenchyma of bone marrow while osteoclasts come from hematopoietic precursors. Both osteoclasts and osteoblasts produce OPN and their activities are crucial for bone remodeling besides osteoid mineralization. Mechanistically increasing evidence suggests that phosphorylated-OPN directly associates with apatite deposits and blocks crystal growth in addition to inducing RGD-mediated mineralization of cardiovascular tissues. Taken together bone marro

RANKL Is a Mediator of Bone Resorption in Idiopathic Hypercalciuria

Background and objectives: This study aimed to determine the expression of osteoprotegerin, receptor activator of nuclear factor κB ligand, interleukin-1α, transforming growth factor-β, and basic fibroblast growth factor in stone-forming patients with idiopathic hypercalciuria

Usefulness of a quick decalcification of bone sections embedded in methyl metacrylate: an improved method for immunohistochemistry

Immunohistochemistry of undecalcified bone sections embedded in methyl methacrylate (MMA) is not commonly employed because of potential destruction of tissue antigenicity by highly exothermic polymerization. The aim of the present study was to describe a new technique in which a quick decalcification of bone sections embedded in MMA improves the results for immunohistochemistry. The quality of interleukin 1 alpha (IL-1 alpha) immunostaining according to the present method was better than the conventional one. Immunostaining for osteoprotegerin (OPG) and the receptor activator of NF-kappa B ligand (RANKL) in bone sections of chronic kidney disease patients with mineral bone disorders (CKD-MBD) was stronger than in controls (postmortem healthy subjects). The present study suggested that this method is easy, fast, and effective to perform both histomorphometry and immunohistochemistry in the same bone fragment, yielding new insights into pathophysiological aspects and therapeutic approaches in bone disease

Expression of Fibroblast Growth Factor 23, Vitamin D Receptor, and Sclerostin in Bone Tissue from Hypercalciuric Stone Formers

Background and objectives Increased bone resorption, low bone formation, and abnormal mineralization have been described in stone formers with idiopathic hypercalciuria. It has been previously shown that the receptor activator of NF-kappa B ligand mediates bone resorption in idiopathic hypercalciuria (IH). the present study aimed to determine the expression of fibroblast growth factor 23 (FGF-23), vitamin D receptor (VDR), and sclerostin in bone tissue from IH stone formers.Design, setting, participants, & measurements Immunohistochemical analysis was performed in undecalcified bone samples previously obtained for histomorphometry from 30 transiliac bone biopsies of idiopathic hypercalciuria stone-forming patients between 1992 and 2002 and 33 healthy individuals (controls). Serum parameters were obtained from their medical records.Results Histomorphometry disclosed 21 IH patients with high and 9 IH patients with normal bone resorption. Importantly, eroded surfaces (ES/BS) from IH patients but not controls were significantly correlated with VDR immunostaining in osteoblasts (r=0.51; P=0.004), sclerostin immunostaining in osteocytes (r=0.41; P=0.02), and serum 1,25-dihydroxyvitamin D (r=0.55; P<0.01). of note, both VDR and sclerostin immunostaining were significantly correlated with serum 1,25-dihydroxyvitamin D in IH patients (r=0.52; P=0.01 and r=0.53; P=0.02, respectively), although VDR and sclerostin expression did not differ between IH and controls. IH patients with high bone resorption exhibited a significantly stronger sclerostin immunostaining than IH patients with normal bone resorption. FGF-23 expression in osteocytes from IH patients did not differ from controls and was not correlated with any histomorphometric parameter.Conclusions These findings suggest the contribution of VDR and sclerostin, as well as 1,25-dihydroxyvitamin D, to increase bone resorption in idiopathic hypercalciuria but do not implicate FGF-23 in the bone alterations seen in these patients.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Div Nephrol, BR-04023900 São Paulo, BrazilUniv São Paulo, Div Nephrol, São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, BR-04023900 São Paulo, BrazilFAPESP: 08/10515-0Web of Scienc

Preservation of urine samples for metabolic evaluation of stone-forming patients

Metabolic evaluation of stone-forming (SF) patients is based on the determination of calcium, oxalate, citrate, uric acid and other parameters in 24-h urine samples under a random diet. A reliable measurement of urinary oxalate requires the collection of urine in a receptacle containing acid preservative. However, urinary uric acid cannot be determined in the same sample under this condition. Therefore, we tested the hypothesis that the addition of preservatives (acid or alkali) after urine collection would not modify the results of those lithogenic parameters. Thirty-four healthy subjects (HS) were submitted to two non-consecutive collections of 24-h urine. the first sample was collected in a receptacle containing hydrochloric acid (HCl 6 N) and the second in a dry plastic container, with HCl being added as soon as the urine sample was received at the laboratory. Additionally, 34 HS and 34 SF patients collected a spot urine sample that was divided into four aliquots, one containing HCl, another containing sodium bicarbonate (NaHCO3 5 g/l), and two others in which these two preservative agents were added 24 h later. Urinary oxalate, calcium, magnesium, citrate, creatinine and uric acid were determined. Urinary parameters were also evaluated in the presence of calcium oxalate or uric acid crystals. Mean values of all urinary parameters obtained from previously acidified 24-h urine samples did not differ from those where acid was added after urine collection. the same was true for spot urine samples, with the exception of urinary citrate that presented a slight albeit significant change of 5.9 % between samples in HS and 3.1 % in SE Uric acid was also not different between pre- and post-alkalinized spot urine samples. the presence of crystals did not alter these results. We concluded that post-delivery acidification or alkalinization of urine samples does not modify the measured levels of urinary oxalate, calcium, magnesium, creatinine and uric acid, and that the change on citrate was not relevant, hence allowing all parameters to be determined in a single urine sample, thus avoiding the inconvenience and cost of multiple 24-h urine sample collections.Universidade Federal de São Paulo, Div Nephrol, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, BR-04023900 São Paulo, BrazilWeb of Scienc

C-Kit(+) Cells Isolated from Developing Kidneys Are a Novel Population of Stem Cells with Regenerative Potential

The presence of tissue specific precursor cells is an emerging concept in organ formation and tissue homeostasis. Several progenitors are described in the kidneys. However, their identity as a true stem cell remains elusive. Here, we identify a neonatal kidney-derived c-kit(+) cell population that fulfills all of the criteria as a stem cell. These cells were found in the thick ascending limb of Henle's loop and exhibited clonogenicity, self-renewal, and multipotentiality with differentiation capacity into mesoderm and ectoderm progeny. Additionally, c-kit(+) cells formed spheres in nonadherent conditions when plated at clonal density and expressed markers of stem cells, progenitors, and differentiated cells. Ex vivo expanded c-kit(+) cells integrated into several compartments of the kidney, including tubules, vessels, and glomeruli, and contributed to functional and morphological improvement of the kidney following acute ischemia-reperfusion injury in rats. Together, these findings document a novel neonatal rat kidney c-kit(+) stem cell population that can be isolated, expanded, cloned, differentiated, and used for kidney repair following acute kidney injury. These cells have important biological and therapeutic implications. STEM Cells 2013;31:1644-1656James and Esther King Florida Biomedical Research ProgramNational Institutes of HealthUniv Miami, Leonard M Miller Sch Med, Interdisciplinary Stem Cell Inst, Miami, FL 33136 USAUniv Miami, Leonard M Miller Sch Med, Dept Mol & Cellular Pharmacol, Miami, FL 33136 USAUniv Miami, Leonard M Miller Sch Med, Dept Surg, Miami, FL 33136 USAUniv Miami, Leonard M Miller Sch Med, Dept Pathol, Miami, FL 33136 USAUniv Miami, Leonard M Miller Sch Med, Div Nephrol & Hypertens, Miami, FL 33136 USAUniv Miami, Leonard M Miller Sch Med, Div Cardiol, Dept Med, Miami, FL 33136 USAAlbert Einstein Hosp, Soc Beneficente Albert Einstein, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, BrazilJames and Esther King Florida Biomedical Research Program: 1KD07-33958National Institutes of Health: HL107110National Institutes of Health: AG025017Web of Scienc