Modifying RANKL/OPG mRNA expression in differentiating and growing human primary osteoblasts.

The OPG/RANKL system in primary cultures of human osteoblasts has been studied by different authors. However, very few studies have been performed on gene expression of RANKL and OPG at different stages of maturation on human osteoblast cultures. The effect of 17- beta-estradiol and 1,25dihydroxyvitamin D3 on the OPG/RANKL system is not known during the different states of cellular maturation. In this work we quantified OPG and RANKL protein levels (ELISA) and the mRNA of OPG, RANKL, collagen type I, alkaline phosphatase, and osteocalcin (semi-quantitative RT-PCR) in human osteoblasts. We analyzed these in basal conditions and after incubation with 17- beta-estradiol and 1,25dihydroxyvitamin D3 in the first and second phases. We found that OPG secretion and expression levels increased throughout cellular growth. RANKL proteins were detected only in the first stage, and the expression increased throughout the first phase. Thus, the RANKL/OPG ratio was higher in immature osteoblasts than in mature osteoblasts. The evolution of RANKL gene expression was related to collagen I and alkaline phosphatase, while OPG was related to osteocalcin. We observed no modifications after estradiol and 1,25dihydroxyvitamin D3 treatment. Our results suggest that the OB is a positive stimulator at precocious stages of differentiation on osteoclastogenic modulates.

Alteraciones en el metabolismo mineral óseo en pacientes con urolitiasis de repetición y polimorfismos del gen del receptor de la vitamina D. Resultados preliminares / Alterations in bone mineral metabolism in patients with calcium kidney stone disease and polymorphism of vitamin D receptor, preliminary results

Existe controversia sobre la afectación ósea en la litiasis renal cálcica. Por otro lado, algunos estudios genéticos han encontrado asociación entre los polimorfismos del receptor de la vitamina D (VDR) y la urolitiasis.Objetivo principal: Relacionar la nefrolitiasis cálcica de repetición con el metabolismo óseo y los polimorfismos del gen del VDR. Material y métodos: Estudio de casos y controles, estando el grupo de casos formado por 51 pacientes con litiasis renal de repetición, que subdividimos enno hipercalciúricos (NHC, n = 27), hipercalciúricos absortivos (HCA, n = 10) e hipercalciúricosrenales (HCR, n = 14); el grupo control, formado por 21 sujetos sin historia de litiasis renal ni hipercalciuria. Se les determinaron parámetros del metabolismo fosfo-cálcico, marcadores de remodelado óseo, densidad mineral ósea (DMO) en columna lumbar y en cuello femoral, y polimorfismos del gen del VDRpara los loci b, a y t. Resultados: Los pacientes litiásicos presentaron frente a los controles una DMO inferior tanto en L2-L4 como en cuello femoral (Z-score, p = 0,045 y 0,031), niveles superiores de 1,25 (OH)2 vitamina D (p = 0,002) e inferiores de PTH (p = 0,049), y una menor ingesta cálcica (p < 0,001). Los HCA mostraron una mayor DMO frente a los NHC (sólo significativo en cuello femoral). Los pacientes con LRC no mostraron diferencias en las frecuencias genotípicas estudiadas frente a los controles. Al reagrupar los alelos, sólo se apreció una menor frecuencia del genotipo BB respecto al Bb-bb, y del tt frente al TT-Tt, en los pacientes litiásicos (p =0,098 y p = 0,051, respectivamente). Conclusiones: La litiasis renal cálcica pareceinfluir en la DMO de cuello femoral. Los pacientes litiásicos mostraron niveles elevados de 1,25 (OH)2 vitamina D, posiblemente relacionado con la baja dieta cálcica. Los genotipos homocigóticos BB y tt parecen ser menos frecuentes entre los pacientes con litiasis renal cálcica

Bone health, within calcium kidney stone disease is a matter of controversy. On the other hand, some genetic studies have shown an association between some Vitamin Dreceptor polymorphisms and calcium kidney stone disease. Main objective: To study the possible association between calcium kidney stone disease with bone metabolismand some Vitamin D receptor polymorphisms. Patients and methods: This is a casecontrol study, with seventy-two subjects of both genders divided into two groups: Group I: cases, composed by 51 patients suffering from calcium kidney stone disease. Twenty-four of them had no hypercalciuria, 16 had absortive hypercalciuria and 11 had renal hypercalciuria. Group II: controls, composed by 21 people, without either urolithiasis or hypercalciuria. We performed a complete study including biochemical markers of bone mineral remodelling, bone mineral density (BMD) was estimatedboth in the lumbar spine (L2-L4) and femoral neck, and also VDR polymorphism for the loci b, a and t. Results: Patients with urolithiasis had lower values of BMD both in the lumbar spine and femoral neck, compared to controls. Z-score were lower in the lumbar spine and femoral neck (p = 0.045 y 0.031, respectively). Those patients with absorptive hypercalciuria had higher BMD in the femoral neck than those with renal hypercalciuria and non-hypercalciuria. Because they had more weight and height all the statistical study was performed alter adjusting by these two variables and statisticalsignificance was then only stated between patients with hypercalciuria and without it. Patients with urolithiasis had higher values of 1.25 (OH)2 vitamin D (p = 0.002), and lower of PTH (p = 0.049), without any relationship to hypercalciuria and its subtypes.Seventy six percent of the patients had a daily calcium intake lower than 800 mg/day. The distribution of VDR alleles in patients with urolithiasis was similar to controls, although after grouping genotypes, a lower distribution of BB and tt polymorphisms wereobserved in patients suffering from urolithiasis. Conclusions: Calcium kidney stone diseaseby itself produces a decrease in BMD, more intense in femoral neck, independently the presence or absence of hypercalciuria. Patients suffering from urolitihiasishave higher values of 1.25 (OH)2 vitamin D than non-hypercalciuric patients and lower values of PTH probably due to a low dietary calcium intake. In our populationstudied there is no relationship between VDR polymorphisms and the presence of calcium kidney stone disease. Because the reduced number of patients of our study,more studies are needed to obtain definitely conclusions

Modulation of the effects of chylomicron remnants on endothelial function by minor dietary lipid components.

There is emerging evidence that minor components from dietary oils can modulate or even improve events occurring in the development of atherosclerosis. One of the earliest events of the atherosclerotic process is endothelial dysfunction, which is an activation of the endothelium manifested by an increase in pro-inflammatory molecules, such as cytokines and adhesion molecules. Chylomicron remnants, such as LDL (low-density lipoprotein), are considered to be pro-atherogenic lipoproteins because they interact with endothelial cells and macrophages, increasing endothelial dysfunction mainly by the disturbance of the redox state in the cell. However, chylomicrons are, at the same time, the natural carriers of dietary lipids in plasma, which gives minor lipid components the opportunity to interact with the cells implicated in endothelial dysfunction and atherogenesis. Some of these components are known to exhibit antioxidant, anti-inflammatory and anti-atherogenic effects in vitro, even forming part of triacylglycerol-rich lipoproteins, such as chylomicrons.

Influence of minor components of olive oils on the composition and size of TRLs and on macrophage receptors involved in foam cell formation.

Metabolic and epidemiologic studies support the idea that the type of dietary fat is more important than the total amount of fat with respect to the development of atherosclerosis and the risk of cardiovascular heart disease. Dietary fat is carried in CMs (chylomicrons), which can be taken up by macrophages without need of further oxidation, leading to the formation of foam cells and initiating or aggravating the atherogenic process. Evidence from different studies has shown that dietary fat can influence the composition and size of TRLs (triacylglycerol-rich lipoproteins), which might modulate their atherogenicity to a certain extent. In particular, experiments in vitro have shown the anti-atherogenic effects of minor components from olive oil when forming part of TRL, as these particles give minor lipid components the opportunity to interact with the cells implicated in endothelial dysfunction and atherogenesis. However, the exact mechanisms mediating CM uptake by macrophages still remain unclear. Thus further studies are needed to understand how the modifications of TRL composition caused by dietary fats could modulate the expression of macrophage receptors and foam cell formation, or even improve the atherogenic risk of these particles.

[Alterations in bone mineral metabolism in patients with calcium kidney stone disease and polymorphism of vitamin D receptor. Preliminary results]. / Alteraciones en el metabolismo mineral óseo en pacientes con urolitiasis de repetición y polimorfismos del gen del receptor de la vitamina D. Resultados preliminares.

UNLABELLED: Bone health, within calcium kidney stone disease is a matter of controversy. On the other hand, some genetic studies have shown an association between some Vitamin D receptor polymorphisms and calcium kidney stone disease. MAIN OBJECTIVE: To study the possible association between calcium kidney stone disease with bone metabolism and some Vitamin D receptor polymorphisms. PATIENTS AND METHODS: This is a case-control study, with seventy-two subjects of both genders divided into two groups: Group I: cases, composed by 51 patients suffering from calcium kidney stone disease. Twenty-four of them had no hypercalciuria, 16 had absortive hypercalciuria and 11 had renal hypercalciuria. Group II: controls, composed by 21 people, without either urolithiasis or hypercalciuria. We performed a complete study including biochemical markers of bone mineral remodelling, bone mineral density (BMD) was estimated both in the lumbar spine (L2-L4) and femoral neck, and also VDR polymorphism for the loci b, a and t. RESULTS: Patients with urolithiasis had lower values of BMD both in the lumbar spine and femoral neck, compared to controls. Z-score were lower in the lumbar spine and femoral neck (p =0,045 y 0,031, respectively). Those patients with absorptive hypercalciuria had higher BMD in the femoral neck than those with renal hypercalciuria and non-hypercalciuria. Because they had more weight and height all the statistical study was performed alter adjusting by these two variables and statistical significance was then only stated between patients with hypercalciuria and without it. Patients with urolithiasis had higher values of 1,25 (OH)2 vitamin D (p=0,002), and lower of PTH (p=0,049), without any relationship to hypercalciuria and its subtypes. Seventy six percent of the patients had a daily calcium intake lower than 800 mg/day. The distribution of VDR alleles in patients with urolithiasis was similar to controls, although after grouping genotypes, a lower distribution of BB and tt polymorphisms were observed in patients suffering from urolithiasis. CONCLUSIONS: Calcium kidney stone disease by itself produces a decrease in BMD, more intense in femoral neck, independently the presence or absence of hypercalciuria. Patients suffering from urolitihiasis have higher values of 1,25 (OH)2 vitamin D than non-hypercalciuric patients and lower values of PTH probably due to a low dietary calcium intake. In our population studied there is no relationship between VDR polymorphisms and the presence of calcium kidney stone disease. Because the reduced number of patients of our study, more studies are needed to obtain definitely conclusions.

Calcitonin reserve in healthy women and patients with postmenopausal osteoporosis.

A deficit of immunoreactive calcitonin (iCT) has been found in women with postmenopausal osteoporosis (PM-OP), however, recent studies assessing the monomeric fraction of calcitonin (exCT) do not seem to confirm these findings. We have measured serum levels of iCT by radioimmunoassay (RIA) and exCT (chromatography and RIA) at 0, 5, 10, and 20 minutes after the i.v. infusion of 2 mg calcium/kg body weight in four different groups of women: (1) 12 healthy premenopausal women (HPM), (2) 16 early postmenopausal women (EPM), (3) 16 postmenopausal women within more than 2 years of menopause (LPM), and (4) 24 women with PM-OP. In the HPM group, iCT levels increased significantly 5 and 10 minutes after finishing the calcium infusion (P less than 0.05); this did not occur in the other three groups. The exCT levels in the HPM and LPM groups showed a significantly greater increase than in the EPM and PM-OP groups at 5 minutes (P less than 0.05) and at 10 and 20 minutes (P less than 0.01) after infusion. The behavior of the PM-OP and EPM groups was similar throughout the study. We conclude that there is a calcitonin reserve deficiency in the first years after menopause, which recovers later. This hormone deficiency could explain the accelerated bone loss that takes place at this time of life. The patients with PM-OP also show this deficit, and this may play an ethiopathogenic role in the production of the disease.

ADFR therapy in the prevention of bone loss after menopause.

Estrogens retard bone loss after menopause and constitute the most logical therapy for the prevention of postmenopausal osteoporosis. Estrogens are contraindicated in some circumstances and some postmenopausal women are unwilling to accept them. We have used ADFR therapy as an alternative in the prevention of postmenopausal bone loss. One hundred women in the early postmenopausal period (6-24 months since the last menses) were introduced into the study. 50 were treated with placebo and 50 were treated with ADFR therapy (phosphorus 1.5 gr/day during 3 days, followed by SCT 100 UI/day during 10 days and calcium 1 gr/day). After 77 days without any therapy we repeated the cycles every 3 months. Bone mass was evaluated at the beginning and at 3, 6, 12 and 18 months by dualphoton absorptionmetry lumbar spine. In the control group, the mean spinal BMD decreased 7.31% after 12 months and 6.16% after 18 months (p greater than 0.05). The ADFR group only had a mean spinal BMD decrease of 3.79% and 1.1% after 12 and 18 months respectively (NS). Bone loss was greater in control than in ADFR group after 12 and 18 months (p less than 0.05 at both times). We conclude that phosphorus and calcitonin like ADFR therapy may be a useful alternative to estrogen for the prevention of accelerated bone loss after menopause.