Low selenium levels are associated with decreased bone mineral densities

PurposeOsteoporosis has a high worldwide prevalence and detrimental consequences (e.g., increased fracture risk). The amount of bone mineral in bone tissue (i.e., bone mineral density [BMD]) is most widely used indicator of osteoporosis in clinical medicine. Selenium is an essential micronutrient for animals and humans. It is a cofactor for antioxidant enzyme reduction (e.g., glutathione peroxidase). It also enhances immune surveillance and modulates cell proliferation. Study findings on the associations between BMD and selenium levels are inadequate and contradictory. The purpose of this study was to examine the associations between hair selenium levels and lumbar spine and femur BMD values.MethodsUsing a cross-sectional study design, we assessed the associations between hair selenium levels and BMD values in 1,167 Korean adults who underwent a health check-up. Each subject was assigned to one of two groups based on BMD (normal group [T-score ≥ -1.0] or low BMD group [T-score < -1.0]). The associations between hair selenium levels and the risk for low BMD were estimated using multivariate logistic regression models.ResultsStudy participants with lower hair selenium levels were older and had higher phosphorous, alkaline phosphatase, and osteocalcin levels. They also had lower BMDs, corrected serum calcium levels, uric acid levels, and creatinine clearance. Participants with low BMDs had significantly lower hair selenium levels (P < 0.001). After adjusting for osteoporosis-related risk factors, the risk of a low BMD was significantly greater for the lower hair selenium quartile groups (P = 0.045).ConclusionIn conclusion, this study found that lower hair selenium levels were associated with low BMD values, independent of the other osteoporosis risk factors examined. Further prospective studies are warranted to determine the role of selenium in the development of osteoporosis.     

Effect of oscillating fluid shear on solute transport in cortical bone

The consequences of an oscillatory fluid shear mechanism on nutrient transport in bone during physical activity and ultrasonic therapy are discussed. During movement, periodic stress on bone creates transient pressure gradients that circulate interstitial fluid through calcified bone. A transport model derived from oscillatory Taylor-Aris dispersion phenomena was used to predict a ratio of effective-to-molecular diffusivity, K/D, for solutes of varying sizes up to 50 nm in diameter, in pores filled with interstitial fluid and pericellular matrix. The magnitude of the estimated transport enhancement depended on the molecular size, pore dimension, applied frequency and the displacement of the fluid during pressurization. For oscillation frequencies and amplitudes corresponding to those experienced during normal human activity, transport enhancements of up to 100 fold are expected for molecules larger than 5 nm in diameter. Enhancements of up to one order of magnitude, due to ultrasound stimulations in the MHz frequency range, are also expected for 7-nm-sized solutes. No effects are anticipated for ions, whose molecular diffusion time is too fast relative to the oscillation frequency. This model is expected to be useful for understanding differences in bone growth as a function of type of movement or to develop new physical therapies.     

Near-infrared photons: a non-invasive probe for studying bone blood flow regulation in humans

The study of bone blood flow regulation in humans has always represented a difficult task for the clinician and the researcher. Classical measurement techniques imply the presence of ionizing radiation or contrast agents, or they are slow or cannot be repeated too often in time. In the present review, we would like to give a perspective on how the optical approach might overcome some of these problems and give unique solutions to the study of bone blood flow regulation. We hope that the present contribution will encourage the scientific community to put a greater attention on this approach.     

Ultrastructural evidence for paracellular fluid flow in the Malpighian tubules of a larval mayfly

The ultrastructure of the Malpighian tubules of larvae of the Mayfly Ecdyonurus dispar (Ephemeroptera) is described. There are about 60 tubules, which consist of four distinct regions. The most proximal section (region I) appears to be responsible for fluid secretion. A unique feature is the presence of channels leading off the main lumen, which end close to the basal border of the cells. Microvilli are confined to these channels in region I. Region II is a short spiral region, the cells of which possess long basal folds and associated mitochondria. Region III is a simple conducting tube leading to one of six collecting ducts (region IV) arranged radially around the gut. In each collecting duct there are two cell types present. Type 2 cells are relatively simple, but give rise to numerous, long, microvilli-like projections. Type 1 cells possess long basal folds, and curious membrane whorls in the apical zone. Evidence is presented which suggest that water movements into region I takes place via the paracellular route. Region II is probably a reabsorptive region, but the function of region IV, based on ultrastructural evidence is more difficult to elucidate.     

Association of P2Y2 receptor SNPs with bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

The P2Y₂ receptor is a G-protein-coupled receptor with adenosine 5′-triphosphate (and UTP) as natural ligands. It is thought to be involved in bone physiology in an anti-osteogenic manner. As several non-synonymous single nucleotide polymorphisms (SNPs) have been identified within the P2Y₂ receptor gene in humans, we examined associations between genetic variations in the P2Y₂ receptor gene and bone mineral density (BMD) (i.e., osteoporosis risk), in a cohort of fracture patients. Six hundred and ninety women and 231 men aged ≥50 years, visiting an osteoporosis outpatient clinic at Maastricht University Medical Centre for standard medical follow-up after a recent fracture, were genotyped for three non-synonymous P2Y₂ receptor gene SNPs. BMD was measured at three locations (total hip, lumbar spine, and femoral neck) using dual-energy X-ray absorptiometry. Differences in BMD between different genotypes were tested using analysis of covariance. In women, BMD values at all sites were significantly different between the genotypes for the Leu46Pro polymorphism, with women homozygous for the variant allele showing the highest BMD values (0.05 > p > 0.01). The Arg312Ser and Arg334Cys polymorphisms showed no differences in BMD values between the different genotypes. This is the first report that describes the association between the Leu46Pro polymorphism of the human P2Y₂ receptor and the risk of osteoporosis.     

Subclinical hypervitaminosis A in rat: measurements of bone mineral density (BMD) do not reveal adverse skeletal changes

We have previously shown that subclinical hypervitaminosis A in rats causes fragile bones. To begin to investigate possible mechanisms for Vitamin A action we extended our previous study. Forty-five mature female Sprague-Dawley rats were divided into three groups, each with 15 animals. They were fed a standard diet containing 12IU Vitamin A per g pellet (control, C), or a standard diet supplemented with 120 IU ("10xC") or 600 IU ("50xC") Vitamin A/g pellet for 12 weeks. At the end of the study, serum retinyl esters were elevated 4- and 20-fold. Although neither average food intake nor final body weights were significantly different between groups, a dose-dependent reduction in serum levels of Vitamin D and E, but not Vitamin K, was found. In the 50xC-group the length of the humerus was the same as in controls, but the diameter was reduced (-4.1%, p<0.05). Peripheral quantitative computed tomography (pQCT) at the diaphysis showed that bone mineral density (BMD) was unchanged and that periosteal circumference had decreased significantly (-3.7%, p<0.05). Ash weight of the humerus was not affected, but since bone volume decreased, volumetric BMD, as measured by the bone ash method, even increased (+2.5%, p<0.05). In conclusion, interference with other fat-soluble Vitamins is a possible indirect mechanism of Vitamin A action. Moreover, BMD measurements do not reveal early adverse skeletal changes induced by moderate excesses of Vitamin A in rats. Since the WHO criterium for osteoporosis is based on BMD, further studies are warranted to examine whether this is also true in humans.     

Proteomics analysis revealed changes in rat bronchoalveolar lavage fluid proteins associated with oil mist exposure

Exposure to oil mist has been associated with a variety of acute and chronic respiratory effects. Using proteomics approaches to investigate exposure-associated proteins may provide useful information to understand the mechanisms of associated respiratory effects. The aim of this study was to investigate changes in rat bronchoalveolar lavage fluid proteins associated with oil mist exposure using nano-HPLC-ESI-MS/MS. The results revealed that 29 proteins exhibited significant changes after exposure. These proteins included surfactant-associated proteins (SP-A and SP-D), inflammatory proteins (complement component 3, immunoglobulins, lysozyme, etc.), growth factors (e.g., transforming growth factor alpha (TGF-alpha)), calcium-binding proteins (calcyclin, calgranulin A, calreticulin, and calvasculin), and other proteins (e.g., cathepsin D, saposin, and intestinal trefoil factor). To further evaluate changes in protein levels, a simple quantitative strategy was developed in this study. A large decrease in protein levels of SP-A and SP-D (0.24- and 0.38-fold, respectively) following exposure was observed. In contrast, protein levels of TGF-alpha and calcium-binding proteins were significantly increased (4.46- and 1.4-1.8-fold, respectively). Due to the diverse functions of these proteins, the results might contribute to understand the mechanisms involved in lung disorders induced by oil mist exposure.     

Adaptive changes in micromechanical environments of cancellous and cortical bone in response to in vivo loading and disuse

The skeleton accommodates changes in mechanical environments by increasing bone mass under increased loads and decreasing bone mass under disuse. However, little is known about the adaptive changes in micromechanical behavior of cancellous and cortical tissues resulting from loading or disuse. To address this issue, in vivo tibial loading and hindlimb unloading experiments were conducted on 16-week-old female C57BL/6J mice. Changes in bone mass and tissue-level strains in the metaphyseal cancellous and midshaft cortical bone of the tibiae, resulting from loading or unloading, were determined using microCT and finite element (FE) analysis, respectively. We found that loading- and unloading-induced changes in bone mass were more pronounced in the cancellous than cortical bone. Simulated FE-loading showed that a greater proportion of elements experienced relatively lower longitudinal strains following load-induced bone adaptation, while the opposite was true in the disuse model. While the magnitudes of maximum or minimum principal strains in the metaphyseal cancellous and midshaft cortical bone were not affected by loading, strains oriented with the long axis were reduced in the load-adapted tibia suggesting that loading-induced micromechanical benefits were aligned primarily in the loading direction. Regression analyses demonstrated that bone mass was a good predictor of bone tissue strains for the cortical bone but not for the cancellous bone, which has complex microarchitecture and spatially-variant strain environments. In summary, loading-induced micromechanical benefits for cancellous and cortical tissues are received primarily in the direction of force application and cancellous bone mass may not be related to the micromechanics of cancellous bone.     

Changes in cell surface primary cilia and microvilli concurrent with measurements of fluid flow across the rabbit corneal endothelium ex vivo

Primary cilia and microvilli have been reported on the mammalian rabbit corneal endothelium but their relationship to cell function is undefined. Six corneas from healthy 2 kg female albino rabbits were glutaraldehyde-fixed post mortem (15:00 h) or twelve corneal stroma-endothelial preparations incubated at 37 degrees C under an applied hydrostatic pressure of 20 cm H2O for 4 h prior to fixation. The corneal endothelium was assessed by quantitative scanning electron microscopy. Cells fixed immediately post mortem were decorated with small stubby microvilli (average 21 +/- 13/100 micron 2), and only 25% of the cells were decorated with primary cilia having an average length of 2.44 +/- 1.56 microns. Following 4 h ex vivo incubation with a phosphate-buffered Ringer solution, conspicuous microvilli developed to an average density of 40 +/- 19/100 micron 2 and primary cilia were found on 12% of the cells, having on average length of 2.27 +/- 1.38 microns. Following 4 h incubation in a bicarbonate-buffered Ringer solution, small stubby microvilli developed to a density of 49 +/- 18/100 micron 2, and 40% of the cells showed primary cilia with an average length of 4.31 +/- 1.93 microns; the net trans-endothelial fluid flow in the latter set was 60% greater. These studies indicate that the primary cilia on corneal endothelial cells might be responsive to fluid flow, but that mild mechanical and/or chemical stress could also be the cause of the change since the elaboration of primary cilia can be accompanied by microvilli as well.     

Comparison between liraglutide alone and liraglutide in combination with insulin on osteoporotic rats and their effect on bone mineral density

Objectives:To compare the therapeutic efficacy of liraglutide (LRG) single drug combined with insulin (Ins) on osteoporosis in rats and its effect on bone mineral density (BMD). A rat model of diabetes combined with osteoporosis was established.Methods:40 Sprague-Dawley rats were divided into four groups (blank, control, LRG and LRG+Ins). Serum levels of CrossLaps, procollagen type I N propeptide (PINP), alkaline phosphatase (AKP) and osteocalcin (BGP) were detected by ELISA. Blood glucose was measured by its reaction with glucose oxidase. Serum insulin was analyzed by radioimmunology. Bone calcium and phosphorus contents were also recorded. ELISA was used to detect inflammatory factors. Bone mineral density (BMD) measurement was also performed.Results:BMD of the control group was significantly lower than that of the other three groups (p<0.05) and BMD of the LRG + Ins group was significantly higher than that of the LRG group (p<0.05). The inflammatory factors of the control group were significantly higher than those in the other three groups (p<0.05). The inflammatory factors were negatively correlated with BMD (p<0.05).Conclusions:liraglutide in combination with insulin for the treatment of diabetes complicated with osteoporosis can reduce blood glucose in vivo, promote production of islet, effectively improve osteoporosis symptoms, increase BMD and reduce the levels of inflammatory factors in vivo.     

The cerebrospinal fluid proteome in HIV infection: change associated with disease severity

Background

Central nervous system (CNS) infection is a nearly universal feature of untreated systemic HIV infection with a clinical spectrum that ranges from chronic asymptomatic infection to severe cognitive and motor dysfunction. Analysis of cerebrospinal fluid (CSF) has played an important part in defining the character of this evolving infection and response to treatment. To further characterize CNS HIV infection and its effects, we applied advanced high-throughput proteomic methods to CSF to identify novel proteins and their changes with disease progression and treatment.

Results

After establishing an accurate mass and time (AMT) tag database containing 23,141 AMT tags for CSF peptides, we analyzed 91 CSF samples by LC-MS from 12 HIV-uninfected and 14 HIV-infected subjects studied in the context of initiation of antiretroviral therapy and correlated abundances of identified proteins a) within and between subjects, b) with all other proteins across the entire sample set, and c) with "external" CSF biomarkers of infection (HIV RNA), immune activation (neopterin) and neural injury (neurofilament light chain protein, NFL). We identified a mean of 2,333 +/- 328 (SD) peptides covering 307 +/-16 proteins in the 91 CSF sample set. Protein abundances differed both between and within subjects sampled at different time points and readily separated those with and without HIV infection. Proteins also showed inter-correlations across the sample set that were associated with biologically relevant dynamic processes. One-hundred and fifty proteins showed correlations with the external biomarkers. For example, using a threshold of cross correlation coefficient (Pearson''s) ≤ -0.3 and ≥0.3 for potentially meaningful relationships, a total of 99 proteins correlated with CSF neopterin (43 negative and 56 positive correlations) and related principally to neuronal plasticity and survival and to innate immunity. Pathway analysis defined several networks connecting the identified proteins, including one with amyloid precursor protein as a central node.

Conclusions

Advanced CSF proteomic analysis enabled the identification of an array of novel protein changes across the spectrum of CNS HIV infection and disease. This initial analysis clearly demonstrated the value of contemporary state-of-the-art proteomic CSF analysis as a discovery tool in HIV infection with likely similar application to other neurological inflammatory and degenerative diseases.     

Specific detection of prion antigenic determinants retained in bovine meat and bone meal by flow microbead immunoassay

AIMS: The purpose of this study was to develop an effective method for detecting prion (PrP) antigenic determinants remaining in bovine meat and bone meal (MBM) using pressurized fluid extraction (PSE) equipment and flow microbead immunoassay (FMI). METHODS AND RESULTS: Using the FMI, bovine recombinant PrP could be determined quantitatively in the 7 pmol-7 nmol range using anti-PrP peptide polyclonal antibody-coupled microbeads and anti-PrP monoclonal antibody (SAF61) as a detection antibody. PSE extraction at 120 degrees C for 5 min under high pressure was most effective for eluting PrP determinants from bovine MBMs. The FMI was capable of detecting PrP determinants in bovine MBM extracts with high specificity and indicated that the MBMs contained high levels of PrP determinants. This assay was also applied to the detection of PrP(Sc) determinants in bovine MBM spiked with a scrapie-infected brain at a weight ratio of 50 : 1. CONCLUSIONS: These data indicate that this assay was effective for the specific detection of PrP determinants contained in bovine MBM extracts. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report detailing the detection of PrP determinants in bovine MBM. The assay could be applied to securing the safety of bovine MBM.     

Propranolol prevents cerebral blood flow changes and pain-related behaviors in migraine model mice

Propranolol, a β-adrenergic receptor blocker, is one of the most commonly used prophylactic drugs for migraines. Cortical spreading depression (CSD) is the propagation wave of neuronal excitation along with cerebral blood flow (CBF) changes over the cerebral cortex and has been implicated in the pathological process of migraine auras and its pain response. However, the effect of propranolol on CSD-related CBF changes and behavioral responses remains poorly understood. In this study, we measured CSD-related CBF responses using a micro-device with a green light emitting diode (LED) and micro-complementary-metal-oxide-semiconductor (CMOS) image sensor and evaluated pain-related reduced locomotor activity in mice. An injection of KCl into the visual cortex led to CSD-related CBF changes; however, propranolol prevented the increase in CBF as well as delayed the propagation velocity in KCl-induced CSD. Furthermore, an injection of KCl reduced locomotor activity and induced freezing behavior in awake and freely moving mice, which were prevented by propranolol treatment. These results suggest that the modulation of CSD-related CBF responses by the blockade of β-adrenergic receptor contributes to its prophylactic effects on migraines.     

Induction of cyclic electron flow around photosystem 1 and state transition are correlated with salt tolerance in soybean

We investigated the role of cyclic electron flow around photosystem 1 (CEF1) and state transition (ST) in two soybean cultivars that differed in salt tolerance. The CEF1 and maximum photochemical efficiency (F_v/F_m) were determined under control and NaCl (50 mM) stress and the NaCl-induced light-harvesting complex 2 (LHC2) phosphorylation in vitro was analysed in light and dark. NaCl induced the increase of CEF1 more greatly in wild soybean Glycine cyrtoloba (cv. ACC547) than in cultivated soybean Glycine max (cv. Melrose). The F_v/F_m was reduced less in G. cyrtoloba than in G. max after 10-d NaCl stress. In G. cyrtoloba, the increase of CEF1 was associated with enhancement of LHC2 phosphorylation in thylakoid membrane under both dark and light. However, in G. max the NaCl treatment decreased the LHC2 phosphorylation. Treatment with photosynthetic electron flow inhibitors (DCMU, DBMIB) inhibited LHC2 phosphorylation more in G. max than in G. cyrtoloba. Thus the NaCl-induced up-regulation in CEF1 and ST might contribute to salt resistance of G. cyrtoloba.     

HDL-like lipoproteins in cerebrospinal fluid affect neural cell activity through lipoprotein-associated sphingosine 1-phosphate

High-density lipoprotein (HDL)-associated sphingosine 1-phosphate mediates a variety of lipoprotein-induced actions in vascular cell systems. However, it remains unknown whether extracellular S1P is associated with lipoproteins to exert biological actions in central nervous system. Human cerebrospinal fluid (CSF) induced rat astrocyte migration in a manner sensitive to S1P receptor antagonist VPC23019 and the migration activity was recovered in S1P fraction by thin-layer chromatography. Density-gradient separation of CSF revealed that the major S1P activity was detected in the HDL fraction. In conditioned medium of rat astrocytes cultured with sphingosine, the S1P activity was recovered again in the HDL fraction. The HDL fraction also induced migration of astrocytes and process retraction of oligodendrocytes in a manner similar to S1P. We concluded that S1P is accumulated in HDL-like lipoproteins in CSF and mediates some of lipoprotein-induced neural cell functions in central nervous system.     

Comparison by flow cytometry of immune changes induced in human monocyte-derived dendritic cells upon infection with dengue 2 live-attenuated vaccine or 16681 parental strain

Dengue is an important threat for world-wide public health. Different vaccines are under development, which are currently assessed using a battery of in vitro and in vivo assays before moving on to humans. It is also important to assess vaccine characteristics on human primary cells; among them, dendritic cells, the most efficient antigen-presenting cells, are the first targets of dengue virus infection. In this study, we used flow cytometry to compare the consequences of such an infection by dengue serotype 2 live-attenuated vaccine (LAV2) or its parental strain DEN2 16681 (DEN2). Optimal conditions of infection have first been defined by a mathematical approach, and flow cytometry allowed studying modifications induced in both infected and noninfected dendritic cell populations after surface and intracellular labeling. Both DEN2 and LAV2 increased the expression of the phenotypic markers CD80, CD86, CD40, CD1a, HLA ABC and CD83, demonstrating cellular activation. Stimulated dendritic cells produced tumor necrosis factor-alpha in particular, and, to a lower extent, interleukin 6. Of importance, whereas DEN2 induced cytokine production both in the infected and noninfected populations, LAV2-induced cytokine production was restricted to the infected population. This limited activation triggered by LAV2 would be in agreement with its attenuation. In conclusion, these in vitro experiments using primary human dendritic cells may participate, in combination with other assays, to the evaluation of the immunogenicity and safety of dengue vaccine candidates.     

Shifts in outcrossing rates and changes to floral traits are associated with the evolution of herbicide resistance in the common morning glory

Human‐mediated selection can strongly influence the evolutionary response of natural organisms within ecological timescales. But what traits allow for, or even facilitate, adaptation to the strong selection humans impose on natural systems? Using a combination of laboratory and greenhouse studies of 32 natural populations of the common agricultural weed, Ipomoea purpurea , we show that herbicide‐resistant populations self‐fertilise more than susceptible populations. We likewise show that anther–stigma distance, a floral trait associated with self‐fertilisation in this species, exhibits a nonlinear relationship with resistance such that the most and least resistant populations exhibit lower anther–stigma separation compared to populations with moderate levels of resistance. Overall, our results extend the general finding that plant mating can be impacted by human‐mediated agents of selection to that of the extreme selection of the agricultural system. This work highlights the influence of human‐mediated selection on rapid responses of natural populations that can lead to unexpected long‐term evolutionary consequences.     

Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae Pv. phaseolicola

The apoplast is the arena in which endophytic pathogens such as Pseudomonas syringae grow and interact with plant cells. Using metabolomic and ion analysis techniques, this study shows how the composition of Phaseolus vulgaris leaf apoplastic fluid changes during the first six hours of compatible and incompatible interactions with two strains of P. syringae pv. phaseolicola (Pph) that differ in the presence of the genomic island PPHGI‐1. Leaf inoculation with the avirulent island‐carrying strain Pph 1302A elicited effector‐triggered immunity (ETI) and resulted in specific changes in apoplast composition, including increases in conductivity, pH, citrate, γ‐aminobutyrate (GABA) and K⁺, that are linked to the onset of plant defence responses. Other apoplastic changes, including increases in Ca²⁺, Fe^2/3+ Mg²⁺, sucrose, β‐cyanoalanine and several amino acids, occurred to a relatively similar extent in interactions with both Pph 1302A and the virulent, island‐less strain Pph RJ3. Metabolic footprinting experiments established that Pph preferentially metabolizes malate, glucose and glutamate, but excludes certain other abundant apoplastic metabolites, including citrate and GABA, until preferred metabolites are depleted. These results demonstrate that Pph is well‐adapted to the leaf apoplast metabolic environment and that loss of PPHGI‐1 enables Pph to avoid changes in apoplast composition linked to plant defences.