Hiperparatiroidismo secundario en el cáncer de próstata avanzado

Background and ObjectiveHigh parathyroid hormone (PTH) concentrations are associated with increased bone resorption and bone matrix degradation. Some studies show elevated PTH concentrations and hypocalcemia in patients with advanced prostate carcinoma, although the pathophysiological significance of these findings is not well defined.Materials and methodsWe performed a retrospective study of 60 patients diagnosed with advanced prostate cancer (44 nonmetastatic and 16 metastatic) treated with androgen deprivation. In all patients, PTH, calcium, phosphorus, 25 (OH) vitamin D and prostate-specific antigen (PSA) were determined. Bone scintigraphy had previously been performed.ResultsIn patients with bone metastases, mean concentrations were as follows: calcium 9.19 mg/dl, phosphorus 3.47 mg/dl, 25 (OH) vitamin D 13.85 ng/ml, PTH 66.8 pg/ml and total PSA 101.27 ng/ml. For those without bone metastases, the results were calcium 9.39 mg/dl, phosphorus 3.38 mg/dl, 25 (OH) vitamin D 20.50 ng/ml, PTH 52.23 pg/ml and total PSA 2.52 ng/ml. PTH levels were significantly higher in patients with prostate cancer and bone metastases than in those without metastases (p=0.03). Vitamin D levels were also significantly lower in this group (p=0.03). There were no differences in other values.ConclusionsThe present study found increased PTH concentrations in patients with advanced prostate cancer. This finding could be useful to predict disease progression.     

The effect of zinc and phytoestrogen supplementation on the changes in mineral content of the femur of rats with chemically induced mammary carcinogenesis

The aim of this study was to assess skeletal effects of zinc or zinc with phytoestrogen (resveratrol or genistein) supplementation in an animal model of rats with DMBA-induced mammary carcinogenesis. The changes in bone parameters such as the length and mass were examined, as well as the changes in concentrations of selected minerals: calcium, magnesium, zinc, iron and phosphorus. Moreover, the investigations focused on finding the differences between the levels of iron and zinc in other tissues: the liver, spleen and serum of the examined rats.Fifty-six female Sprague–Dawley rats, 40 days old, were divided into four groups, regardless of the diets: standard (77 mg Zn kg/food), zinc (4.6 mg/mL via gavage), zinc (4.6 mg/mL) plus resveratrol (0.2 mg/kg bw), and zinc (4.6 mg/mL) plus genistein (0.2 mg/kg bw) for a period from 40 days until 20 weeks of age. The study rats were also treated with 7,12-dimethyl-1,2-benz[a]anthracene (DMBA) to induce mammary carcinogenesis.The applied diet and the advanced mammary cancer did not affect macrometric parameters of the rats’ bones, but they strongly affected their mineral content. It was found that mammary cancer, irrespectively of the applied diet, significantly modified the iron level in the femur, liver, spleen and serum of the examined rats. In addition, zinc supplementation significantly lowered the levels of calcium, magnesium and phosphorus in the femur of rats with mammary cancer as compared with respective levels in the control group. So, it was found that additional supplementation with zinc, which is generally considered to be an antioxidant, with the co-existing mammary carcinoma, increased the unfavorable changes as concerns the stability of bone tissue. The appropriate combination of zinc and phytoestrogens (resveratrol or genistein) could help prevent or slow bone loss associated with a range of skeletal disorders in breast cancer.     

Does Baseline PTH Influence Recovery of Bone Mineral Density,Trabecular Bone Score and Bone Turnover Markers? A Prospective Study Following Curative PArathyroidectomy in Primary Hyperparathyroidism

Objective: This prospective study was carried out to assess trabecular bone score, bone mineral density (BMD), and bone biochemistry in Indian subjects with symptomatic primary hyperparathyroidism (PHPT), and to study the influence of baseline parathyroid hormone (PTH) on recovery of these parameters following curative surgery.Methods: This was a 2-year prospective study conducted at a tertiary care centre in southern India. Baseline assessment included demographic details, mode of presentation, bone mineral biochemistry, BMD, trabecular bone score (TBS), and bone turnover markers (BTMs). These parameters were reassessed at the end of the first and second years following curative parathyroid surgery.Results: Fifty-one subjects (32 men and 19 women) with PHPT who had undergone curative parathyroidectomy were included in this study. The mean (SD) age was 44.6 (13.7) years. The TBS, BTMs, and BMD at lumbar spine and forearm were significantly worse at baseline in subjects with higher baseline PTH (≥250 pg/mL) when compared to the group with lower baseline PTH (<250 pg/mL). At the end of 2 years, the difference between high versus low PTH groups (mean ± SD) persisted only for forearm BMD (0.638 ± 0.093 versus 0.698 ± 0.041 g/cm²; P =.01). However, on follow-up visits in the first and second year after curative parathyroidectomy, there was no significant difference in BTMs, BMD at the femoral neck, lumbar spine, and TBS between the 2 groups stratified by baseline PTH.Conclusion: The BMD at the forearm remained significantly worse in individuals with high baseline PTH even at 2 years after surgery, while other parameters including TBS improved significantly from baseline.Abbreviations: 25(OH)D = 25-hydroxyvitamin D; BMD = bone mineral density; BMI = body mass index; BTMs = Bone turnover markers; CTX = C-terminal telopeptide of type 1 collagen; DXA = dual energy X-ray absorptiometry; P1NP = N-terminal propeptide of type 1 procollagen; PHPT = primary hyperparathyroidism; PTH = parathyroid hormone; TBS = trabecular bone score     

Effects of dietary aluminum source and concentration on mineral status of feeder lambs

A 100 d experiment was conducted to determine the effects of aluminum (Al) source and concentration on mineral status, emphasizing phosphorus (P), of 50 feeder lambs. Six treatments, fed at 10% of the total diet, were formulated using two sources of Al, AlCl₃ and an Al-based water treatment residual (WTR, 11.1% Al), with varying levels of Al and P: (1) control (10% sand, C), (2) low WTR (2.5% WTR and 7.5% sand, L-WTR), (3) AlCl₃ with added P (1% AlCl₃, 9% sand, and 0.4% P, AlCl₃ + P), (4) high WTR (10% WTR, H-WTR), (5) AlCl₃ (1% AlCl₃ and 9% sand, AlCl₃), and (6) high WTR with added P (10% WTR and 0.4% P, H-WTR + P). The total Al varied from 0.037 to 1.2% among diets. Only lambs fed the high WTR diet without P supplementation (H-WTR) decreased feed intakes. These lambs consumed about half as much feed as lambs on all the other treatments, and had lower (P < 0.05) BW from d 84 on. Lambs receiving the H-WTR had the lowest bone Ca, P and Mg concentrations (fresh basis, mg/cm³) and lowest bone mineral content (BMC) as determined by radiographs (mm of Al). Results for the lambs on H-WTR were confounded by the greatly reduced feed intake of animals on this treatment. Plasma P decreased in all lambs consuming Al, regardless of Al source, but the effects were less severe in animals provided additional P supplementation (AlCl₃ + P and H-WTR + P). Apparent absorption of P was affected by concentration and source of Al in two metabolism trials (n = 42) beginning on d 34 and d 70, respectively. In the first trial, d 34, lambs receiving AlCl₃ treatment had reduced apparent P absorption, −17.7% (P < 0.05), when compared to all other treatments. In the d 70 trial, lambs receiving both AlCl₃ and H-WTR treatments were negatively impacted (P < 0.05) compared to the control, −20.9 and −2.5% apparent P absorption, respectively, but were no longer different from one another (P > 0.05). Diets containing 1.2% Al as WTR without P supplementation depressed feed intakes, weight gains, plasma P concentrations (P < 0.05), and BMC. However, given adequate P supplementation, even lambs consuming this amount of Al did not suffer detrimental effects, as lambs on H-WTR + P did not differ from the control (P > 0.05) in feed intakes, weight gains, or BMC.     

Effect of Zhen Qi Fu Zheng granules on the bone marrow depression model induced by Zidorf

Zidorf is a commonly used drug for the treatment of AIDS, the most common side effects of AZT was bone marrow depression. Therefore, we investigated the effects of Zhen Qi Fu Zheng (AQFZ) granules on the model of bone marrow depression induced by AZT. We showed that the high, medium and low doses of AQFZ granules could increase the number of WBC in the mice model induced by AZT, and the difference was significant (P < 0.01) compared with the model group. Each dose of AQFZ granules can increase the thymus cortex thickness, the number of thymus lymphocytes, spleen nodule size, the number of lymphocytes in the spleen (P < 0.01). The medium dose of AQFZ granules can also significantly improve the number of BMC in the bone marrow depression model (P < 0.01). As well as, the low dose of AQFZ granules can clearly increase the number of nucleated cells in a bone marrow (P < 0.05) and IL-2blood serum. So, AQFZ granules can improve and regulate the hemogram, bone marrow and immune level of bone marrow depression model induced by AZT.     

Age-related effects of major and trace element concentrations in rat liver and their mutual relationships

The concentrations of 22 major and trace elements in livers from rats aging from 5 to 113 weeks old were determined. The rats investigated were the same rats previously reported with respect to 29 elements in bones (femur) and 26 elements in kidneys. The samples were decomposed with high-purity nitric acid and hydrogen peroxide. Seven elements (Na, Mg, P, K, Ca, Fe and Zn) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), and 15 elements (Mn, Co, Cu, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Pb and Bi) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Analysis of variance (ANOVA) for age variations indicated that the concentrations of many elements, such as Mg, P, K, Mn, Fe, Cu, Zn, Sr, Mo and Cd, were almost constant across the ages of the rats with the exception of 5 weeks old (p > 0.05). Arsenic, Pb and Bi showed significant increasing trends, while Na and Co showed decreasing trends (p < 0.01). Selenium showed a decreasing trend except at the initial stage of 5–9 weeks old. Calcium, Rb, Sn, Sb, Cs and Ba showed significant age-related variations, but their patterns were not monotonic. The liver clearly contrasts with the kidneys, in which many elements showed significant age-related variations with increasing trends. The concentration ranges of Mg, P, K, Mn, Cu, Zn, and Mo were controlled within 15% across all ages of rats. The homeostasis of the aforementioned elements may be well established in the liver. The toxic elements, such as Cd, Pb and Bi, showed a narrow concentration range among age-matched rats.     

The concentrations of major and trace elements in rat kidney: Aging effects and mutual relationships

The concentrations of 26 major to trace elements in rat kidneys aging from 5 to 113 weeks old were determined. The rats investigated were the same rats used previously reported to have 29 elements in bones (femurs). The samples were decomposed by high purity nitric acid and hydrogen peroxide. Eight elements (Na, Mg, Si, P, K, Ca, Fe and Zn) were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES) and 18 elements (Mn, Co, Ni, Cu, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Tl, Pb, Bi and U) were determined using inductively coupled plasma mass spectrometry (ICP-MS). The aging effects on the concentrations of these elements and mutual elemental relationships were investigated. Analysis of variance (ANOVA) for age variations indicated that the concentrations of P, K, Mn and Mo were almost constant across the age of rats (p > 0.3). The concentration of many elements such as Na, Mg, Ca, Fe, Co, Cu, Zn, As, Se, Cd, Sn, Sb, Tl, Pb and Bi, showed significant increasing trends (p < 0.01) with different patterns. Rubidium, Cs, Pb and Bi showed significant age variations but not monotonic trends. Silicon, Ni, Sr, Ba and U showed large concentration scatterings without any significant trends (p > 0.01). The metabolism of these elements may not be well established in the kidney. Many toxic elements such as As, Cd, Sn, Pb and Bi showed a narrow concentration range among age-matched rats. The kidney may have established metabolic mechanisms to confine or accumulate these toxic elements even though their concentrations are very low (e.g., 10 ng g^?1 of Cd). These elements also closely coupled with Fe. A cluster analysis was performed using an elemental correlation matrix and indicated that these elements, including Fe, formed a cluster. However, another cluster analysis using “an aging effect eliminated” elemental correlation showed different clustering in which the Fe, Cd cluster disappeared.     

Zinc status and bone mineralisation in adolescent girls.

The aim of the project was to assess the relationship between zinc status and bone mineralisation in pre-menarcheal adolescent girls. One hundred and thirty-nine healthy pre-menarcheal girls (Tanner pubic hair stage < or = 4), aged 12.4 +/- 1.0 years, had two visits at an interval of 2 years. Serum and urine zinc concentrations (Zn S; Zn U; Zn U/ creatinine), insulin-like growth factor 1 (IGF-I), and markers of bone turn-over, i.e. osteocalcin and parathormone (PTH), concentrations were measured at the first visit. Lumbar (L2-L4) bone mineral content and density (BMC, BMD) were measured at both visits. BMC and BMD and their increase at the follow-up after 2 years were compared with biochemical data by multiple regression. The stage of puberty was added as a covariable in the analysis. At the first visit, a significant correlation was found between sexual maturity and initial BMC, BMD, height, weight, and IGF-I. Zn S was negatively correlated with osteocalcin. Zn U showed a positive correlation with BMC, BMD, IGF-I, height, weight, and PTH. At the second visit, sexual maturity showed a positive correlation with BMD and weight increments and a negative one with BMC and height gains. Zn S was significantly related with BMD increase. These correlations suggest that zinc plays a role in normal growth and bone mineralisation during puberty onset.     

Effects of zinc pre-treatment on blood glutathione,serum zinc and kidney histological organisation in male rats exposed to cadmium

The effects of sub-chronic exposure to cadmium (Cd) on the blood glutathione, serum zinc and on the kidney histological organisation in rats as well as the possible protective role of zinc (Zn) are the object of this study. For this purpose, 60 male Wistar rats (8 weeks old) were divided into three groups: the first group was exposed to Cd in the form of CdCl₂, administered in five doses (each of 0.4 mg Cd/kg b.w.) on days 5, 10, 15, 20 and 25, giving a total dose of 2 mg Cd/kg b.w., i.p.; the second group was simultaneously exposed to Zn and Cd with the same timeline and the same doses of Cd as the first group but with, in addition, injections of Zn in the form of ZnCl₂, administered in doses of 0.8 mg Zn/kg b.w., giving a total dose of 4 mg Zn/kg b w, i.p.; a control group received 0.5 mL of physiological saline in an identical manner. Intoxication with Cd was followed by a significant decrease in blood glutathione, increase in oxidized glutathione as well as histological damage in kidneys. Pre-treatment with Zn exhibited a protective role against Cd toxicity with a significant decrease in serum zinc content. This fact may be explained by an excessive use of zinc in metallothionein synthesis as a cadmium detoxification agent.     

Parathyroid hormone gene with bone phenotypes in Chinese

Osteoporosis is a common disorder afflicting old people. The parathyroid hormone (PTH) gene is involved in bone remodeling and calcium homeostasis, and has been considered as an important candidate gene for osteoporosis. In this study, we simultaneously tested linkage and/or association of PTH gene with bone mineral density (BMD) and bone mineral content (BMC), two important risk factors for osteoporosis. A sample of 1263 subjects from 402 Chinese nuclear families was used. The families are composed of both parents and at least one healthy daughter aged from 20 to 45 years. All the subjects were genotyped at the polymorphic BstBI site inside the intron 2 of the PTH gene (a nucleotide substitution of G to A at the position +3244). BMD and BMC were measured at the lumbar spine and the hip region via dual-energy X-ray absorptiometry (DXA). Using QTDT (quantitative trait transmission disequilibrium test), we did not find significant results for association or linkage between the PTH gene and BMD or BMC variation at the spine or hip. Our data do not support the PTH gene as a quantitative trait locus (QTL) underlying the bone phenotypic variation in the Chinese population.     

Abnormalities of Vitamin D and Calcium Metabolism after Surgical Treatment of Morbid Obesity: A Study of 136 Patients

ObjectiveTo assess the effect of bariatric surgical treatment of morbid obesity on bone mineral metabolism.MethodsWe analyzed pertinent vitamin D and calcium metabolic variables in 136 patients who had undergone a malabsorptive bariatric operation. Measurements of bone mineral density (BMD), serum 25-hydroxyvitamin D (25-OHD), 1,25-dihydroxyvitamin D [1,25-(OH)₂D], parathyroid hormone (PTH), calcium, phosphorus, and alkaline phosphatase were performed. Statistical analyses assessed correlations among various factors.ResultsThe mean age (± SD) of the study group was 48.34 ± 10.28 years. Their mean weight loss was 114.55 ± 45.66 lb, and the mean duration since the bariatric surgical procedure was 54.02 ± 51.88 months. Seventeen patients (12.5%) had a T-score of -2.5 or less, and 54 patients (39.7%) had a T-score between –1.0 and –2.5. Of 119 patients in whom serum 25-OHD was measured, 40 (34%) had severe hypovitaminosis D (25-OHD < 8 ng/mL), and 50 patients (42%) had low hypovitaminosis D (serum 25-OHD 8 to 20 ng/mL). The magnitude of weight loss correlated negatively with serum 25-OHD, calcium, phosphorus, and calcium × phosphorus product values and positively with serum alkaline phosphatase level. Serum 25-OHD and calcium concentrations correlated positively with the BMD. PTH, serum 1,25-(OH)₂D, and alkaline phosphatase concentrations correlated negatively with the BMD, a reflection of the presence of secondary hyperparathyroidism, an accelerated conversion of 25-OHD to 1,25-(OH)₂D by the elevated PTH levels, and increased osteoblastic activity. The mean daily vitamin D supplementation was 6,472 ± 9,736 IU.ConclusionHypovitaminosis D and subsequent bone loss are common in patients who have undergone a bariatric surgical procedure for morbid obesity. These patients require rigorous vitamin D supplementation. (Endocr Pract. 2007;13:131-136)     

EDTA disodium zinc has superior bioavailability compared to common inorganic or chelated zinc compounds in rats fed a high phytic acid diet

Different zinc (Zn) compounds have unique properties that may influence the amount of Zn absorbed particularly in the presence of phytic acid (PA), a common food component that binds Zn and decreases its bioavailability. In this study, 30-day-old male rats (n = 12/diet group) were fed diets supplemented with PA (0.8%) and low levels (8 mg Zn/kg diet) of inorganic (Zn oxide, Zn sulphate) or chelated (Zn gluconate, Zn acetate, Zn citrate, EDTA disodium Zn, Zn orotate) Zn compounds for 5 weeks. Two control groups were fed diets supplemented with low or normal (30 mg Zn/kg diet) Zn (as Zn oxide) without added PA. Control rats fed the low Zn oxide diet showed depressed Zn status. Addition of PA to this diet exacerbated the Zn deficiency in rats. Growth (body weight gain and femur length) and Zn concentrations in plasma and tissues were similar in rats fed Zn oxide, Zn sulphate, Zn gluconate, Zn acetate, Zn citrate or Zn orotate. Rats fed EDTA disodium Zn showed enhanced growth compared to rats fed Zn oxide or Zn gluconate and had higher Zn concentrations in plasma and femur compared to rats fed all other Zn compounds. Only the haematological profile of rats fed EDTA disodium Zn did not differ from control rats fed normal Zn. These data indicate that in rats fed a high PA diet, bioavailability of commonly used inorganic or chelated Zn compounds does not differ appreciably, but Zn supplied as an EDTA disodium salt has superior bioavailability.     

Local bone formation due to combined mechanical loading and intermittent hPTH-(1-34) treatment and its correlation to mechanical signal distributions

We evaluated the local response of cortical bone in the rat tibia due to combined treatment with synthetic parathyroid hormone, hPTH-(1-34), and mechanical stimulation by four-point bending. Forty-eight female retired breeder Sprague-Dawley rats were divided into six groups. Mechanically stimulated animals included the following groups: (1) Bend+PTH, (2) Sham+PTH, (3) Bend+Vehicle, (4) Sham+Vehicle. Non-mechanically stimulated animals included a (5) Control group that received neither loading nor injections, and a (6) PTH group that received only hPTH-(1-34) injections. The right limbs of mechanically loaded animals were exposed to a peak force of 50 N for 36 cycles at 2 Hz, three days per week for four weeks, and PTH-treated animals received injections equivalent to 50 μg/kg BW. Fluorochrome labeling was used to measure local formation at 12 sectors about the endocortical periphery. The distributions of endocortical bone formation were compared to the local formation differences between treatment groups and to a variety of potential mechanical stimuli signals. Results indicated that hPTH-(1-34) exerted a potent anabolic effect with near-uniform formation about the endocortical surface, and that localized formation peaks due to bending were further augmented in the presence of hPTH-(1-34) treatment. Correlation of formation patterns to mechanical signal distributions highlighted several candidate signals including the mid-principal stress, the dilatational strain, and the radial gradient of the local radial strain.     

Moderate Zinc Supplementation During Prolonged Steroid Therapy Exacerbates Bone Loss in Rats

The present study was conducted to understand the influence of zinc on bone mineral metabolism in prednisolone-treated rats. Disturbance in bone mineral metabolism was induced in rats by subjecting them to prednisolone treatment for a period of 8 weeks. Female rats aged 6–8 weeks weighing 150 to 200 g were divided into four treatment groups, viz., normal control, prednisolone-treated (40 mg/kg body weight orally, thrice a week), zinc-treated (227 mg/L in drinking water, daily), and combined prednisolone?+?zinc-treated groups. Parameters such as changes in mineral levels in the bone and serum, bone mineral density (BMD), bone mineral content (BMC), and bone 99m-technetium-labeled methylene diphosphonate (^99mTc-MDP) uptake were studied in various treatment groups. Prednisolone treatment caused an appreciable decrease in calcium levels both in the bone and serum and also in bone dry weight, BMC, and BMD in rats. Prednisolone-treated rats when supplemented with zinc showed further reduction in calcium levels, bone dry weight, BMD, and BMC. The study therefore revealed that moderate intake of zinc as a nutritional supplement during steroid therapy could enhance calcium deficiency in the body and accelerate bone loss.     

Comparative analysis of serum zinc,copper, magnesium,calcium and iron level in acute and chronic patients of visceral leishmaniasis

ProjectChronic visceral leishmaniasis (VL) is an increasingly common problem in disease endemic states of India. Identification of prognosis risk factor in patients with VL may lead to preventive actions, toward decreasing its mortality in chronic individuals. Though serum Zinc levels are decreased in patients of VL, limited information is available regarding trace elements status in acute and chronic VL patients. The present study was undertaken to compare serum trace elements concentrations in acute and chronic VL patients.ProcedureAcute (mean age = 28.64 years), chronic (mean age = 23.68 years) VL patients and healthy controls (mean age = 23.05 years) who agreed to provide blood specimens for laboratory investigations participated in this study. Serum zinc (Zn), copper (Cu), iron (Fe), magnesium (Mg) and calcium (Ca) were measured spectrophotometrically using chemistry analyzer.ResultsSerum Zn concentration was comparatively much decreased in chronic VL than to acute ones (p = 0.007) while serum Mg was higher in chronic VL than acute (p = 0.002) ones. There was no statistically significant difference between acute and chronic VL in serum concentrations of Cu, Fe and Ca.ConclusionsSerum Zn levels were much decreased and serum Mg were increased in chronic VL as compared to acute cases. The serum concentrations of Fe and Ca did not show any difference between two groups. The serum Cu was increased in both groups but more in chronic ones. Serum Zn and Mg could be a potential prognosis factor for chronic VL patients. We hypothesize zinc supplementation as a chemo preventive agent for chronic VL cases, particularly in endemic areas.     

Effects of zinc deficiency and zinc supplementation on homocysteine levels and related enzyme expression in rats

Methionine synthase (MS) and betaine-homocysteine methyltransferase (BHMT) are both zinc (Zn)-dependent methyltransferases and involved in the methylation of homocysteine. The objective of this study was to investigate the effects of dietary Zn supply on homocysteine levels and expression of the two enzymes in growing rats. Male weanling Sprague-Dawley rats were assigned randomly to four dietary groups (n = 8/group) for 3 weeks: Zn deficient (ZD; <1 mg Zn/kg); Zn control (ZC; 30 mg Zn/kg); Zn supplemented (ZS; 300 mg Zn/kg); pair fed (PF; 30 mg Zn/kg) to the ZD group. Serum and femur Zn concentrations were 83% and 58% lower in ZD, and 49% and 62% higher in ZS compared to ZC (P < 0.001), respectively. The ZD rats had lower feed intake (37%), body weight gains (45%), liver (43%) and kidney (31%) weights than those of ZC (P < 0.001), but these parameters in ZD were not significantly different from the PF controls. Serum homocysteine concentrations were 65% higher in ZD compared to PF (P < 0.05), and there was no significant difference in serum folate levels between ZD and PF groups. The mRNA expression of liver and kidney MS was 57% and 38% lower in ZD than PF (P < 0.001), respectively. Hepatic and renal BHMT mRNA levels were not altered in ZD compared to controls. The aforementioned measurements were not significantly different between ZS and ZC groups, except Zn levels. These results demonstrated that homocysteine homeostasis appeared to be disturbed by Zn deficiency but not Zn supplementation, and elevated serum homocysteine might be due to reduced expression of MS during Zn deficiency.     

Efectos del tratamiento con ácido zoledrónico en pacientes adultos con osteogénesis imperfecta

Background and objectiveOsteogenesis imperfecta (OI) is a genetic disorder that results in bone fragility. Several studies have demonstrated the effectiveness of bisphosphonate therapy. The aim of this study was to evaluate the effects of intravenous zoledronic acid on bone mineral density (BMD) and biochemical markers of bone turnover in adults with OI.Material and methodsWe carried out a prospective non-randomized study in patients with osteoporosis or severe osteopenia (T score <?2) related to OI and intolerance or contraindication to oral bisphosphonates. The patients were treated with a zoledronic acid infusion every 6 months. Densitometry was carried out annually. Calcium (Ca), phosphate (P), intact parathormone (PTH), 25 hydroxyvitamin D and biochemical markers of bone turnover [bone alkaline phosphatase (BAP), beta-cross-laps (CTX) and urinary deoxypyridoxine (DOP)] were measured every year. Adverse events and new fractures were registered.ResultsTen patients (2 men and 8 women) were treated. Treatment increased BMD measured in the lumbar spine after 24 (0.738±0.141 vs 0.788±0.144 g/cm²; p=0.048) and 36 months (0.720±0.139 vs 0.820±0.128; p=0.01). Significant increases in BMD were also observed after 24 months in the femoral neck (0.677±0.121 vs 0.703±0.122 g/cm²; p<0.016). Serum Ca, P, BAP and CTX concentrations remained unchanged. PTH concentrations increased and vitamin D concentrations decreased after 36 months of treatment. DOP excretion decreased significantly after 24 months. Seven patients had mild influenza-like symptoms occurring within the first 24 h after the first infusion. No severe adverse events were observed. None of the patients had new fractures.ConclusionZoledronic acid seems to be a safe and effective treatment option in adults with osteoporosis related to OI.     

Dietary boron supplementation enhances the effects of estrogen on bone mineral balance in ovariectomized rats

The present study investigated whether boron would enhance the action of 17β-estradiol (E₂) or parathyroid hormone (PTH) on bone mineral balance in ovariectomized (OVX) rats. Forty-three days after OVX, the rats were treated for 5 wk with vehicle, boron (5 ppm as boric acid), E₂ (30 μg/kg/d, sc), PTH (60 μg/kg/d, sc), or a combination of boron and E₂ or PTH. Bone mineral balance was assessed by measuring apparent absorption, excretion, and retention of calcium (Ca), phosphorus (P), and magnesium (Mg). Serum Ca, P, Mg, and osteocalcin were also measured in this experiment. Boron alone had no effects on food consumption, weight gain, bone mineral balance, and serum levels of Ca, P, Mg, and osteocalcin. E₂ alone increased serum P and Mg and decreased serum osteocalcin, but it had no effect on bone mineral balance. The combination of boron and E₂ markedly improved apparent absorption of Ca, P, and Mg. In addition, the combination treatment increased the apparent retention of Ca and Mg (but not P) and also increased serum Ca and Mg but not serum P. On the other hand, boron cotreatment did not prevent the E₂-induced reduction in serum osteocalcin in OVX rats. PTH alone significantly increased serum Ca, P, Mg, and osteocalcin concentrations, although it had no effect on bone mineral balance. Contrary to the boron-E₂ combination treatment, the combination of boron and PTH did not enhance bone mineral balance. However, inasmuch as boron-PTH cotreatment did not enhance the stimulatory action of PTH on serum Ca, P, and osteocalcin, boron completely abolished the stimulatory effect of PTH on serum Mg. In conclusion, we have demonstrated for the first time that although boron by itself has no effect on bone mineral homeostasis, it appears to have synergistic enhancing effects on the action of E₂ on Ca and Mg homeostasis in OVX rats.     

Antiosteoporotic activity of icariin in ovariectomized rats

Icariin was evaluated for its antiosteoporotic activity in an ovariectomized rat model of osteoporosis. The rats were divided into sham and OVX groups. The OVX rats were then subdivided into five groups treated with water, nylestriol (1 mg/kg body weight, weekly, orally) or icariin (ICA) (5, 25, and 125 mg/kg body weight, daily, orally) for 12 weeks. In OVX rats, the increases of body weight, serum BGP and ALP were significantly decreased by ICA treatment. In OVX rats, atrophy of uterus and descent of BMD were suppressed by treatment with ICA. In addition, ICA (125 mg/kg body weight) completely corrected the decreased serum concentration of Calcium, Phosphorus, and E₂ observed in OVX rats. ICA (125 mg/kg body weight) increased biomechanical strength significantly in comparison to the sham group. Histological results also showed its protective action through promotion of bone formation. The findings, assessed on the basis of biochemical, bone mineral density, biomechanical, and histopathological parameters, showed that ICA has a definite antiosteoporotic effect, similar to estrogen, especially effective for prevention bone fracture induced by estrogen deficiency.