Protein expression profiles in hematopoietic stem/progenitor cells after exposure of mice to silicon (28Si) ions

It has been well recognized that exposure to space radiation is a major challenge to space exploration. To protect astronauts in space environments, improvement in our knowledge of radiation-induced changes in specific target cells that may affect the health of astronauts is required. Cancer of blood cells, in particular myeloid leukemia (ML), is one of the major health concerns from exposure to space radiation. However, the predictions of risks for developing ML post-exposure to space radiation are unsatisfactory. To increase the reliability of predicting risk for ML, a much improved understanding of space radiation-induced changes in the target cells, i.e. hematopoietic stem/progenitor cells (HSPCs), is critically important. In vivo studies of humans are not possible. Thus, controlled and randomized animal experiments are critically important.

Most proteomic applications mentioned above have used 2-DE or stable isotope-tagged mass spectrometry. Although the 2-DE has several advantages (e.g. the detection of potential post-translational modifications of proteins which can be readily visualized on the gel, although the exact type of modification requires determination by mass spectrometry), such technology is simply not as comprehensive and reliable as desired. To overcome these limitations, we recently developed a unique label-free quantitative mass spectrometry (LFQMS) platform [ 1]. This is an innovative, experimentally based method that accurately determines peptide peak retention-time and uses multiple filters for exclusion of unqualified peptides by peptide frequency, retention time, intensity coefficient of variation and intensity correlation to enhance protein quantification of qualified peptides and proteins.

In this study, we used the LFQMS platform to examine protein expression-profiles in the colonies of HSPCs (the best population of cells for studying in vivo biological effects of radiation on hematopoietic stem cells) obtained at 6 months after exposure (at which radiation-induced genomic instability and chronic inflammation have been detected [ 2]) of CBA/CaJ mice whole-body to a total dose of 0, 0.1, 0.25 or 0.5 Gy of 300 MeV/nucleon ²⁸Si ions, using a fractionated schedule (two exposures, 15 days apart that totaled each selected dose). These doses of 300 MeV/nucleon ²⁸Si ions are comparable to what astronauts encounter in space. Mice exposed to 0 Gy of ²⁸Si ions served as non-irradiated sham controls. The colonies of HSPCs were obtained from BM cells of five mice per treatment group, by means of an in vitro colony forming unit assay (CFU-A) using methylcellulose-based medium. Proteins were extracted from HSPC colonies and protein concentrations were determined by the Bradford Protein Assay. The trans-proteomic pipeline (TPP) was used to assign a probability of a particular protein being in the sample.

A total of 1344 unique, non-redundant proteins were identified with ≥90% confidence from 3254 peptides, quantified and their abundances were compared statistically. Among the 1344 proteins, differential expression of 198 proteins was found to be statistically significant in HSPC colonies obtained from treated groups, in relation to those found in non-irradiated sham controls. A proof-of-concept-based Ingenuity Pathway Analysis (IPA, www.ingenuity.com) was used to characterize the functions and pathways of these 198 identified proteins. The majority of these proteins are cancer-related (P < 0.0001). Biochemical analyses of the molecular and cellular functions of these proteins reveal association with perturbation in cell survival, free radical scavenging, cell cycle, DNA repair, cellular assembly, hematological system development and inflammatory responses. These proteins are linked to two major molecular networks that are linked to cancer and inflammatory responses (i.e. nuclear factor-κ B and the protein phosphatase 2 A networks). Our results indicated ²⁸Si ion-induced damage in HSPCs.

Measuring apparent trabecular structure with pQCT: a comparison with HR-pQCT

We evaluated how comparable peripheral quantitative computed tomography (pQCT) measurements of cortical thickness, density, and apparent trabecular structure at the ultradistal tibia were with those measured with high-resolution pQCT (HR-pQCT). We also examined whether the accuracy of the pQCT-based trabecular and cortical measurements improved with reductions in slice thickness from the standard 2.2mm to 1.1 and 0.6mm. We immersed 15 dry tibia specimens in saline in a sealed cylinder and scanned 22.5mm from the distal tibia plateau using pQCT and HR-pQCT. pQCT underestimated cortical thickness by Stratec (CThStratec) and trabecular spacing (Tb.Sp) by 21.4% and 72.9%, whereas bone volume to total volume (BV/TV) and cortical density (CDen) were overestimated by 265.8% and 13.1%, respectively. Measurements of trabecular volumetric bone mineral density, trabecular area, total area, cortical thickness by custom software were comparable, but for CThStratec, Tb.Sp, BV/TV, and CDen, the differences between imaging devices varied with magnitude of the estimate. We recommend that researchers or clinicians interested in using pQCT to measure apparent trabecular structure or cortical thickness at the epiphyses, or in comparing findings from different devices, be aware of the differences between HR-pQCT and pQCT.

The cost of care of systemic lupus erythematosus (SLE) in the UK: annual direct costs for adult SLE patients with active autoantibody-positive disease

Objectives

The aim of the Systemic LUpus Erythematosus Cost of Care In Europe (LUCIE) study was to evaluate the annual direct medical costs of managing adults with active autoantibody-positive disease on medication for SLE in secondary care. This paper presents the UK analyses only.

Methods

A cost-of-illness study was conducted from the perspective of the National Health Service. Health resource utilization data were retrieved over a two-year period from four centres in England and unit cost data were taken from published sources.

Results

At baseline, 86 patients were included, 38 (44.2%) had severe SLE and 48 (55.8%) had non-severe SLE. The mean (SD) SELENA-SLEDAI score was 7.7 (5.7). The mean (SD) annual direct medical cost of was estimated at £3231 (£2333) per patient and was 2.2 times higher in patients with severe SLE compared with patients with non-severe SLE ( p < 0.001). Multivariate model analyses showed that renal disease involvement ( p = 0.0016) and severe flares ( p = 0.0001) were associated with higher annual direct costs.

Conclusions

Improvement of the overall stability of SLE and early intervention to minimize the impact of renal disease may be two approaches to mitigate the long-term direct cost of managing SLE patients in the UK.

Persistence of brodifacoum in cockroach and woodlice: implications for secondary poisoning during rodent eradications

When planning rodent eradications, that normally involve the use of the anticoagulant poison brodifacoum, it is imperative to minimise impacts on other "non-target" species that dwell alongside the targeted rodents and may indeed be the intended beneficiaries of the eradication. Such impacts can arise either from primary poisoning when the non-target species ingest bait pellets containing toxicant or by secondary poisoning when the non-target species eats prey that has itself eaten brodifacoum. Cockroaches and woodlice, likely to scavenge bait pellets, are widely distributed on tropical and sub-tropical islands where they are eaten by ground-dwelling birds. Combining work on Henderson Island, South Pacific, site of a recent rat eradication project, and UK laboratory experiments, our study first measured brodifacoum concentrations in cockroaches given temporary ad lib access to poison bait pellets, approximately mimicking the aftermath of bait distribution for a rodent eradication. In two separate experiments using different species/exposure times, the mean brodifacoum concentrations among cockroaches immediately after bait exposure was 262±s.e. 131 and 477±168µgkg(-1) wet weight. Values decreased quickly in the following 2 weeks, and then continued to decline at a slower rate over the following 4 weeks in the more prolonged laboratory experiment. A supplementary experiment with woodlice recorded a similar brodifacoum concentration in the animals at the end of the exposure period, 223±66µgkg(-1), and a similar time course for the post-exposure decline. In the context of rails (Rallidae), a group of birds known to be particularly susceptible to primary brodifacoum poisoning, these results suggested that, in terms of acute exposure, individual birds would need to eat a minimum of their own body weight (and more commonly 2-5 times that) of live cockroaches before facing a 50% risk of death. Therefore, we conclude that in eradication scenarios, acute secondary poisoning is of lower concern for these birds than primary poisoning.

Pulmonary arterial hypertension in SLE: what do we know?

Pulmonary hypertension (PH) can occur at any time during the course of systemic lupus erythematosus (SLE), and can be independent of lupus disease activity in other systems. The pathogenesis of PH in SLE can be multifactorial, but pulmonary arterial hypertension (PAH) is the commonest cause of PH in SLE. The international PH registries have published that approximately 15% of connective tissue disease-associated PH is lupus related in their cohorts. As the symptoms of PH in SLE can be mild and non-specific in early stages, an increasing awareness of this devastating complication is essential for early diagnosis. Echocardiographic evaluation of several right heart variables in addition to systolic pulmonary artery pressure estimation reduces false positive rates for PH detection. Antiphospholipid antibodies may predict SLE-PAH. Prompt treatment of PAH with newer PAH therapy as well as immunosuppression can reduce morbidity and prolong survival. The survival in SLE-associated PAH is better compared with systemic sclerosis-associated PH but worse than idiopathic PAH. Pregnancy in SLE-PAH can result in a fatal outcome, especially in severe and poorly controlled PH at onset.

The effects of the histone deacetylase inhibitor 4-phenylbutyrate on gap junction conductance and permeability

Longitudinal resistance is a key factor in determining cardiac action potential propagation. Action potential conduction velocity has been shown to be proportional to the square root of longitudinal resistance. A major determinant of longitudinal resistance in myocardium is the gap junction channel, comprised connexin proteins. Within the ventricular myocardium connexin43 (Cx43) is the dominantly expressed connexin. Reduced numbers of gap junction channels will result in an increase in longitudinal resistance creating the possibility of slowed conduction velocity while increased numbers of channels would potentially result in an increase in conduction velocity. We sought to determine if inhibition of histone deacetylase (HDAC) by 4-phenylbutyrate (4-PB), a known inhibitor of HDAC resulted in an increase in junctional conductance and permeability, which is not the result of changes in single channel unitary conductance. These experiments were performed using HEK-293 cells and HeLa cells stably transfected with Cx43. Following treatment with increasing concentrations of 4-PB up-regulation of Cx43 was observed via Western blot analysis. Junctional (g_j) conductance and unitary single channel conductance were measured via whole-cell patch clamp. In addition intercellular transfer of lucifer yellow (LY) was determined by fluorescence microscopy. The data in this study indicate that 4-PB is able to enhance functional Cx43 gap junction coupling as indicated by LY dye transfer and multichannel and single channel data along with Western blot analysis. As a corollary, pharmacological agents such as 4-PB have the potential, by increasing intercellular coupling, to reduce the effect of ischemia. It remains to be seen whether drugs like 4-PB will be effective in preventing cardiac maladies.

Breast cancer in systemic lupus erythematosus

OBJECTIVE

Evidence points to a decreased breast cancer risk in systemic lupus erythematosus (SLE). We analyzed data from a large multisite SLE cohort, linked to cancer registries.

METHODS

Information on age, SLE duration, cancer date, and histology was available. We analyzed information on histological type and performed multivariate logistic regression analyses of histological types according to age, SLE duration, and calendar year.

RESULTS

We studied 180 breast cancers in the SLE cohort. Of the 155 cases with histology information, 11 were referred to simply as 'carcinoma not otherwise specified'. In the remaining 144 breast cancers, the most common histological type was ductal carcinoma (n = 95; 66%) followed by lobular adenocarcinoma (n = 11; 8%), 15 cancers were of mixed histology, and the remaining ones were special types. In our regression analyses, the independent risk factors for lobular versus ductal carcinoma was age [odds ratio (OR) 1.07, 95% confidence interval (CI) 1.01-1.14] and for the 'special' subtypes it was age (OR 1.06, 95% CI 1.01-1.10) and SLE duration (OR 1.05, 95% CI 1.00-1.11).

CONCLUSIONS

Generally, up to 80% of breast cancers are ductal carcinomas. Though our results are not definitive, in the breast cancers that occur in SLE, there may be a slight decrease in the ductal histological type. In our analyses, age and SLE duration were independent predictors of histological status.

Evaluation of cartilage, synovium and adipose tissue as cellular sources for osteochondral repair

Osteochondral lesions are a major cause of pain and disability in several species including dogs, horses and human beings. The objective of this study was to assess three potential sources of canine cells for their osteochondral regenerative potential. Cartilage, synovium and adipose tissue cells were grown in pellet culture in chondrogenic or osteogenic media. Cartilage-derived pellets displayed the best chondrogenic differentiation as indicated by significantly higher COL2A1 and SOX9 mRNA expression, greater glycosaminoglycan content, and higher retention of Safranin-O stain compared to the synovium and adipose-derived cells. Following application of the osteogenic media, all three cell sources exhibited small areas of positive alizarin red staining. Poor intracellular alkaline phosphatase activity was found in all three cell types when stimulated although osteocalcin and RUNX2 expression were significantly increased. Cells isolated and cultured from canine articular cartilage retained their specific chondrocytic phenotype. Furthermore, canine adipocytes and synovial cells did not undergo chondrogenic differentiation and did not exhibit evidence of multipotency. Although osteogenic differentiation was initiated at a genomic level, phenotypic osteoblastic differentiation was not observed. The findings of this study suggest that cells isolated from canine adipose tissue and synovium are sub-optimal substitutes for chondrocytes when engineering articular cartilage in vitro.

Management of borderline personality disorder

This article gives an overview of personality disorders, with a focus on borderline personality disorder. It also describes the setting up of a trust-wide service to treat people with BPD, led by mental health workers and using guided formulation. The role of guided formulation in the management of BPD is explored. It is suggested that this form of treatment can greatly improve outcomes for patients.

The effects of rat mesenchymal stem cells on injury progression in a rat model

OBJECTIVES

Burns are common injuries that can result in significant scarring, leading to poor function and disfigurement. Unlike mechanical injuries, burns often progress both in depth and in size over the first few days after injury, possibly due to inflammation and oxidative stress. A major gap in the field of burns is the lack of an effective therapy that reduces burn injury progression. Because stem cells have been shown to improve healing in several injury models, the authors hypothesized that species-specific mesenchymal stem cells (MSCs) would reduce injury progression in a rat comb-burn model.

METHODS

Using a brass comb preheated to 100°C, the authors created four rectangular burns, separated by three unburned interspaces on both sides of the backs of male Sprague-Dawley rats. The interspaces represented the ischemic zones surrounding the central necrotic core. In an attempt to reduce burn injury progression, 20 rats were randomized to tail vein injections of 1 mL of rat-specific MSCs, 10(6) cells/mL (n = 10), or normal saline (n = 10), 60 minutes after injury.

RESULTS

While the authors were unable to identify any quantum dot (Q-dot)-labeled MSCs in the injured skin, at 7 days the mean percentage of the unburned interspaces that became necrotic in the MSC group was significantly less than in the control group (80% vs. 100%, p < 0.0001).

CONCLUSIONS

Intravenous injection of rat MSCs reduced burn injury progression in a rat comb-burn model.

Can gap junctions deliver?

In vivo delivery of small interfering RNAs (siRNAs) to target cells via the extracellular space has been hampered by dilution effects and immune responses. Gap junction-mediated transfer between cells avoids the extracellular space and its associated limitations. Because of these advantages cell based delivery via gap junctions has emerged as a viable alternative for siRNA or miRNA delivery. Here we discuss the advantages and disadvantages of extracellular delivery and cell to cell delivery via gap junction channels composed of connexins. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.

Decreased breast cancer risk in systemic lupus erythematosus: the search for a genetic basis continues

PURPOSE

Recent work has demonstrated an important decrease in breast cancers for women with systemic lupus erythematosus (SLE). The reason behind this phenomenon is unknown. Our purpose was to explore whether the single nucleotide polymorphisms (SNPs) predisposing to SLE might be protective against breast cancer (in women in the general population).

METHODS

We focused on loci relevant to 10 SNPs associated with SLE (with a p value of <10(-9)). We determined whether we could establish a decreased frequency of these SNPs in breast cancer cases versus controls, within the general population. To do this we used a large breast cancer genome-wide association study (GWAS) dataset, involving 3,659 breast cancer cases and 4,897 controls. These subjects were all primarily of European ancestry.

RESULTS

The population-based GWAS breast cancer data we examined suggested little evidence for important associations between breast cancer and SLE-related SNPs. Within the general population GWAS data, a cytosine(C) nucleotide substitution at rs9888739 (on chromosome 16p11.2) showed a very weak inverse association with breast cancer. The odds ratio (OR) for the rs9888739-C allele was 0.907551 (p value 0.049899) in the GWAS breast cancer sample, compared to controls. There was a slightly stronger, positive, association with breast cancer for rs6445975-G (Guanine) on chromosome 3p14.3, with a breast cancer OR of 1.0911 (p value 0.0097).

CONCLUSIONS

Within this large breast cancer dataset, we did not demonstrate important associations with 10 lupus-associated SNPs. If decreased breast cancer risk in SLE is influenced by genetic profiles, this may be due to complex interactions and/or epigenetic factors.

Comparison of cortical bone measurements between pQCT and HR-pQCT

The primary purpose of this study was to determine the accuracy of tibial cortical thickness measurements derived from peripheral quantitative computed tomography (pQCT) with analysis based on the circular ring model, using high-resolution peripheral quantitative computed tomography (HR-pQCT) (isotopic voxel size of 82 μm) as a gold standard. The secondary objective was to evaluate whether the accuracy of the pQCT-based estimates of cortical thickness (CTh), cortical area (CoA), cortical density (CDen), and total area (TotA) improve with alterations of voxel size from the standard 0.5-0.2mm. Fifteen dry tibia specimens were immersed in saline in a sealed cylinder and scanned 22.5mm from the distal tibia plateau using pQCT and HR-pQCT. pQCT yielded higher values for CTh and CDen and lower values for CoA. The differences between imaging techniques increased as the average CTh increased. No systematic bias was observed for CDen, CoA, and TotA. Similar differences were found between pQCT with voxel size 0.2mm and HR-pQCT. Significant correlations were observed for CTh (R=0.97, p ≤ 0.0001), CDen (R=0.99, p ≤ 0.0001), CoA (R=0.98, p ≤ 0.0001), and TotA (R=1.0, p ≤ 0.0001) when pQCT- and HR-pQCT-derived values were compared irrespective of which voxel size was used. Measurement variability between the imaging techniques was evident. Future studies aimed at examining cortical structure with pQCT should note that there are differences between the 2 techniques.