No association between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women: a one-year prospective study

Abstract

Introduction: The aim of the study was to explore the association between the vitamin D pathway gene variations and the bone biomarkers response to calcium and low dose calcitriol supplementation in postmenopausal Chinese women.

Methods: A total of 110 healthy postmenopausal Chinese women (61.51?±?6.93?years) were enrolled. The participants were supplemented with calcium (600?mg/d) and calcitriol (0.25?μg/d), for 1?year. Four biomarkers, serum levels of beta C-terminal cross-linked telopeptides of type I collagen (β-CTX), amino-terminal propeptide of type I collagen (P1NP), parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] were measured at baseline and 12-month follow-up. Multivariate regression models were established to explore the statistical association between the change rate of the four biomarkers and 15?key genes within the vitamin D metabolic pathway.

Results: This exclusion process left 98 participants for analysis. Serum levels of P1NP, β-CTX and PTH were significantly decreased at the 12-month follow-up (all p?<?0.05). Serum 25(OH)D level had no significant change (p?>?0.05). No association was found between the vitamin D pathway gene polymorphisms and bone biomarkers response to calcium and low dose calcitriol supplementation.

Conclusions: Genetic background of postmenopausal Chinese women might not influence supplemental response of the biomarkers to calcium and low dose calcitriol.     

Lipopolysaccharide neutralization by a novel peptide derived from phosvitin

Lipopolysaccharide (LPS), also known as endotoxin, is the primary trigger of sepsis, which is associated with high mortality in patients. No therapeutic agents are currently efficacious enough to protect patients from sepsis characterized by LPS-mediated tissue damage and organ failure. Previously, a phosvitin-derived peptide, Pt5, which consists of the C-terminal 55 residues of zebrafish phosvitin, has been shown to function as an antibacterial agent. In this study, we have generated six mutants by site-directed mutagenesis based on the sequence of Pt5, and found that one of the six mutants, Pt5e, showed the strongest bactericidal activities against Escherichia coli and Staphylococcus aureus. We then demonstrated that Pt5e was able to bind to LPS and lipoteichoic acid (LTA). More importantly, we showed that Pt5e significantly inhibited LPS-induced tumor-necrosis factor (TNF)-α and interleukin (IL)-1β release from murine RAW264.7 cells and considerably reduced serum TNF-α and IL-1β levels in mice. Additionally, Pt5e protected the liver from damage by LPS, and remarkably promoted the survival rate of the endotoxemia mice. Furthermore, Pt5e displayed no cytotoxicity to murine RAW264.7 macrophages and no hemolytic activity toward human red blood cells. These data together indicate that Pt5e is an endotoxin-neutralizing agent with a therapeutic potential in clinical treatment of LPS-induced sepsis.     

Noninvasive positron emission tomography imaging of cell death using a novel small-molecule probe, 18F labeled bis(zinc(II)-dipicolylamine) complex

The synthetic bis(zinc(II)-dipicolylamine) (DPAZn2) coordination complexes are known to have a high specific and selective affinity to target the exposed phosphatidylserine (PS) on the surface of dead and dying cells. An ¹⁸F-labeled DPAZn2 complex (4-¹⁸F-Fluoro-benzoyl-bis(zinc(II)-dipicolylamine), ¹⁸F-FB-DPAZn2) as positron emission tomography (PET) tracer was developed and evaluated for in vivo imaging of tumor treated with a chemical agent. The in vitro cell stain studies revealed that fluorescent DPAZn2 complexes (Dansyl-DPAZn2) stained the same cells (apoptotic and necrotic cells) as fluorescein isothiocyanate (FITC) labeled Annexin V (FITC-Annexin V). The radiosynthesis of ¹⁸F-FB-DPAZn2 was achieved through the amidation the precursor bis(2,2′-dipicolylamine) derivative (DPA2) with the prosthetic group N-succinimidyl-4-[¹⁸F]-fluorobenzoate (¹⁸F-SFB) and chelation with zinc nitrate. In the biodistribution study, the fast clearance of ¹⁸F-FB-DPAZn2 from blood and kidney was observed and high uptake in liver and intestine within 90 min postinjection was also found. For the PET imaging, significantly higher tumor uptake of ¹⁸F-FB-DPAZn2 was observed in the adriamycin (ADM)-treated Hepa1-6 hepatocellular carcinoma-bearing mice than that in the untreated tumor-model mice, while a slightly decreased tumor uptake of ¹⁸F-FDG was found in the ADM-treated tumor-bearing mice. The results indicate that ¹⁸F-FB-DPAZn2 has the similar capability of apoptosis detection as FITC-Annexin V and seems to be a potential PET tracer for noninvasive evaluation and monitoring of anti-tumor chemotherapy. The high uptake of ¹⁸F-FB-DPAZn2 in the abdomen needs to optimize the structure for improving its pharmacokinetics characteristics in the future work.     

A New Coronary Retroinfusion Technique in theRat Infarct Model: Transjugular Cardiac Vein Catheterization

Cell delivery via the retrograde coronary route boasts less vessel embolism, myocardial injury, and arrhythmogenicity when compared with those via antegrade coronary administration or myocardial injection. However, conventional insertion into the coronary sinus and consequent bleeding complication prevent its application in small animals. To overcome the complication of bleeding, we described a modified coronary retroinfusion technique via the jugular vein route in rats with myocardial infarction (MI). A flexible wire with a bent end was inserted into the left internal jugular vein and advanced slowly along the left superior vena cava. Under direct vision, the wire was run into the left cardiac vein by rotating the wire and changing the position of its tip. A fine tube was then advanced along the wire to the left cardiac vein. This modified technique showed less lethal hemorrhage than the conventional technique. Retroinfusion via transjugular catheter enabled efficient fluid or cell dissemination to the majority areas of the free wall of the left ventricle, covering the infarcted anterior wall. In conclusion, transjugular cardiac vein catheterization may make retrocoronary infusion a more safe and practical route for delivering cell, drug, and gene therapy into the infarcted myocardium of rats.     

Soil nitrous oxide emissions following crop residue addition: a meta‐analysis

Annual production of crop residues has reached nearly 4 billion metric tons globally. Retention of this large amount of residues on agricultural land can be beneficial to soil C sequestration. Such potential impacts, however, may be offset if residue retention substantially increases soil emissions of N₂O, a potent greenhouse gas and ozone depletion substance. Residue effects on soil N₂O emissions have gained considerable attention since early 1990s; yet, it is still a great challenge to predict the magnitude and direction of soil N₂O emissions following residue amendment. Here, we used a meta‐analysis to assess residue impacts on soil N₂O emissions in relation to soil and residue attributes, i.e., soil pH, soil texture, soil water content, residue C and N input, and residue C : N ratio. Residue effects were negatively associated with C : N ratios, but generally residue amendment could not reduce soil N₂O emissions, even for C : N ratios well above ca. 30, the threshold for net N immobilization. Residue effects were also comparable to, if not greater than, those of synthetic N fertilizers. In addition, residue effects on soil N₂O emissions were positively related to the amounts of residue C input as well as residue effects on soil CO₂ respiration. Furthermore, most significant and stimulatory effects occurred at 60–90% soil water‐filled pore space and soil pH 7.1–7.8. Stimulatory effects were also present for all soil textures except sand or clay content ≤10%. However, inhibitory effects were found for soils with >90% water‐filled pore space. Altogether, our meta‐analysis suggests that crop residues played roles beyond N supply for N₂O production. Perhaps, by stimulating microbial respiration, crop residues enhanced oxygen depletion and therefore promoted anaerobic conditions for denitrification and N₂O production. Our meta‐analysis highlights the necessity to connect the quantity and quality of crop residues with soil properties for predicting soil N₂O emissions.     

Association between osteoprotegerin gene polymorphisms and cardiovascular disease in type 2 diabetic patients

Osteoprotegerin (OPG) gene polymorphisms (T245G, T950C and G1181C) have been associated with osteoporosis and early predictors of cardiovascular disease. The aim of this study was to evaluate whether these polymorphisms contribute to cardiovascular disease (CVD) in type 2 diabetic patients. We performed a case-control study with 178 CVD subjects with diabetes and 312 diabetic patients without CVD to assess the impact of variants of the OPG gene on the risk of CVD. The OPG gene polymorphisms were analyzed by using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). There was no significant association between the T245G and G1181C polymorphisms and CVD in the additive genetic model (OR = 0.96, 95% CI 0.64–1.45, p = 0.79; OR = 1.06, 95% CI 0.81–1.39, p = 0.65, respectively). However, the C allele of the T950C polymorphism was independently associated with a risk of CVD in type 2 diabetic patients in this genetic model (OR = 1.38, 95% CI 1.07–1.80, p = 0.01). This study provides evidence that the C allele of the T950C polymorphism is associated with increased risk of CVD in diabetic patients. However, well-designed prospective studies with a larger sample size are needed to validate these results.     

Nitrate signals determine the sensing of nitrogen through differential expression of genes involved in nitrogen uptake and assimilation in finger millet

In order to understand the molecular basis of high nitrogen use efficiency of finger millet, five genes (EcHNRT2, EcLNRT1, EcNADH-NR, EcGS, and EcFd-GOGAT) involved in nitrate uptake and assimilation were isolated using conserved primer approaches. Expression profiles of these five genes along with the previously isolated EcDof1 was studied under increased KNO₃ concentrations (0.15 to 1,500 μM) for 2 h as well as at 1.5 μM for 24 h in the roots and shoots of 25 days old nitrogen deprived two contrasting finger millet genotypes (GE-3885 and GE-1437) differing in grain protein content (13.76 and 6.15 %, respectively). Time kinetics experiment revealed that, all the five genes except EcHNRT2 in the leaves of GE-3885 were induced within 30 min of nitrate exposure indicating that there might be a greater nitrogen deficit in leaves and therefore quick transportation of nitrate signals to the leaves. Exposing the plants to increasing nitrate concentrations for 2 h showed that in roots of GE-3885, NR was strongly induced while GS was repressed; however, the pattern was found to be reversed in leaves of GE-1437 indicating that in GE-3885, most of the nitrate might be reduced in the roots but assimilated in leaves and vice-versa. Furthermore, compared with the low-protein genotype, expression of HNRT2 was strongly induced in both roots and shoots of high-protein genotype at the least nitrate concentration supplied. This further indicates that GE-3885 is a quick sensor of nitrogen compared with the low-protein genotype. Furthermore, expression of EcDof1 was also found to overlap the expression of NR, GS, and GOGAT indicating that Dof1 probably regulates the expression of these genes under different conditions by sensing the nitrogen fluctuations around the root zone.     

Physiological mechanisms for plant distribution pattern: responses to flooding and drought in three wetland plants from Dongting Lake, China

Both flooding and drought are important in determining plant distribution in wetlands. However, the roles of plant’s physiological response to flooding and drought in accounting for plant distribution are far from clear. To this end, three typical wetland plants with different distribution patterns (high-elevation species Miscanthus sacchariflorus, low-elevation species Carex brevicuspis and Polygonum hydropiper) in Dongting Lake were treated with three water levels (flooding 25 cm, control 0 cm, drought ?25 cm), and relative growth rate (RGR), malondialdehyde (MDA) content, electrolyte leakage and proline content were investigated. The RGR of the three species decreased significantly in both flooding and drought treatments. Compared to the control, the RGR of M. sacchariflorus decreased more in the flooding treatment but less in the drought treatment compared to the other two species. The contents of MDA in the three species increased in both flooding and drought treatments, except for P. hydropiper in the flooding treatment. MDA contents increased more in M. sacchariflorus in the flooding treatment but less in the drought treatment compared to the other two species. Only M. sacchariflorus had a higher electrolyte leakage in the flooding treatment, and drought led to a higher electrolyte leakage in P. hydropiper and C. brevicuspis. Proline content increased 69.2, 66.7 and 39.6 % in P. hydropiper, C. brevicuspis and M. sacchariflorus in the flooding treatment, and increased 44.2, 13.0 and 45.3 % in the drought treatment, respectively. These results suggest that M. sacchariflorus has a higher tolerance to drought but a lower tolerance to flooding than do the other two species, which might be the intrinsic mechanisms accounting for their different distribution patterns.