Age-related changes in mesenchymal stem cells identified using a multi-omics approach

Mesenchymal stem cells (MSC) are capable of multipotent differentiation into connective tissues and as such are an attractive source for autologous cell-based treatments for many clinical diseases and injuries. Ageing is associated with various altered cellular phenotypes coupled with a variety of transcriptional, epigenetic and translational changes. Furthermore, the regeneration potential of MSCs is reduced with increasing age and is correlated with changes in cellular functions. This study used a systems biology approach to investigate the transcriptomic (RNASeq), epigenetic (miRNASeq and DNA methylation) and protein alterations in ageing MSCs in order to understand the age-related functional and biological variations, which may affect their applications to regenerative medicine. We identified no change in expression of the cellular senescence markers. Alterations were evident at both the transcriptional and post-transcriptional level in a number of transcription factors. There was enrichment in genes involved in developmental disorders at mRNA and differential methylated loci (DML) level. Alterations in energy metabolism were apparent at the DML and protein level. The microRNA miR-199b-5p, whose expression was reduced in old MSCs, had predicted gene targets involved in energy metabolism and cell survival. Additionally, enrichment of DML and proteins in cell survival was evident. Enrichment in metabolic processes was revealed at the protein level and in genes identified as undergoing alternate splicing. Overall, an altered phenotype in MSC ageing at a number of levels implicated roles for inflamm-ageing and mitochondrial ageing. Identified changes represent novel insights into the ageing process, with implications for stem cell therapies in older patients.

Ultra-stable sub-meV monochromator for hard X-rays

A high-resolution silicon monochromator suitable for 21.541 keV synchrotron radiation is presented that produces a bandwidth of 0.27 meV. The operating energy corresponds to a nuclear transition in (151)Eu. The first-of-its-kind, fully cryogenic design achieves an energy-alignment stability of 0.017 meV r.m.s. per day, or a 100-fold improvement over other meV-monochromators, and can tolerate higher X-ray power loads than room-temperature designs of comparable resolution. This offers the potential for significantly more accurate measurements of lattice excitation energies using nuclear resonant vibrational spectroscopy if combined with accurate energy calibration using, for example, high-speed Doppler shifting. The design of the monochromator along with its performance and impact on transmitted beam properties are presented.

Long-term effectiveness of a community-based model of care in Māori and Pacific patients with type 2 diabetes and chronic kidney disease: a 4-year follow up of the DElay Future End Stage Nephropathy due to Diabetes (DEFEND) study

BACKGROUND/AIM

The Delay Future End Stage Nephropathy due to Diabetes study was a randomised controlled trial of Māori and Pacific patients with advanced diabetic nephropathy, comparing a community-based model of care with usual care. The intervention group achieved lower blood pressure (BP), proteinuria and less end-organ damage. After the intervention ended, all patients reverted to usual care, and were followed to review the sustainability of the intervention.

METHODS

A retrospective observation of 65 patients (aged 47-75 years) with type 2 diabetes, hypertension, chronic kidney disease 3/4 and proteinuria (>0.5 g/day) previously randomised to intervention/community care or usual care for 11-21 months. Follow up thereafter was until death, end-stage renal disease (ESRD) (estimated glomerular filtration rate (eGFR) ≤ 10 mL/min/1.73 m(2) )/dialysis or 1 February 2014. Primary end-points were death and ESRD/dialysis. Secondary outcomes were annualised glomerular filtration rate decline, non-fatal vascular events and hospitalisations.

RESULTS

Median (interquartile ranges (IQR)) post-trial follow up was 49 (21-81) months and similar in both groups. The median (IQR) eGFR decline was -3.1 (-5.5, -2.3) and -5.5 (-7.1, -3.0) mL/min/year in the intervention and usual care groups respectively (P = 0.11). Similar number of deaths, renal and vascular events were observed in both groups. At the end of follow up, the number of prescribed antihypertensive medications was similar (3.4 ± 1.0 vs 3.3 ± 1.4; P = 0.78). There were fewer median (IQR) hospital days (8 (3, 18) vs 15.5 (6, 49) days, P = 0.03) in the intervention group.

CONCLUSIONS

Short-term intensive BP control followed by usual care did not translate into reduction in long-term mortality or ESRD rates, but was associated with reduced hospitalisations.

Estimating orientation factors in the FRET theory of fluorescent proteins: the TagRFP-KFP pair and beyond

The orientation factor κ(2), one of the key parameters defining Förster resonance energy transfer efficiency, is determined by the transition dipole moment orientations of the donor and acceptor species. Using the results of quantum chemical and quantum mechanical/molecular mechanical calculations for the chromophore-containing pockets in selected colored proteins of the green fluorescent protein family, we derived transition dipole moments corresponding to the S0,min → S1 excitation for green fluorescent protein, red fluorescent protein (TagRFP), and kindling fluorescent protein, and the S1,min → S0 emission for TagRFP. These data allowed us to estimate κ(2) values for the TagRFP-linker-kindling fluorescent protein tetrameric complex required for constructing novel sensors.

Increased awareness and health care provider endorsement is required to encourage pregnant women to be vaccinated

Maternal immunization is an important strategy recommended to protect both mothers and infants from serious infectious diseases; however uptake of maternal immunization is poor in Australia. This study aimed to gain an in-depth understanding of the decision making process and factors influencing a pregnant woman's decisions about recommended immunizations. This qualitative study used semi-structured interviews with open-ended questions to interview pregnant women. Data were analyzed using thematic analysis techniques and drew on the Health Belief Model. Pregnant women (n = 17) were asked about their attitudes toward immunization during pregnancy and their perceptions about risk during pregnancy. Women were also asked to detail their decision making process and factors influencing their decisions about immunizations in relation to pregnancy. Most of the participants were not aware of the immunizations recommended during pregnancy, in pregnancy planning or after delivery. In addition to endorsement by their health care provider (HCP), perception of risk and benefit, including risk of infection, previous vaccination experiences and assessing cost benefit play a vital role in women's decisions whether to be immunized while pregnant. Although the role of the healthcare provider in advising pregnant women about immunizations was identified as vitally important, the majority of women had not been advised of recommended vaccines by their healthcare provider. Healthcare providers are key to ensuring pregnant mothers are informed about recommended vaccines and these need to be more proactively supported and encouraged by healthcare providers. This is likely to have a positive effect on acceptance and uptake of immunization by pregnant women.

Multiphoton photochemistry of red fluorescent proteins in solution and live cells

Genetically encoded fluorescent proteins (FPs), and biosensors based on them, provide new insights into how living cells and tissues function. Ultimately, the goal of the bioimaging community is to use these probes deep in tissues and even in entire organisms, and this will require two-photon laser scanning microscopy (TPLSM), with its greater tissue penetration, lower autofluorescence background, and minimum photodamage in the out-of-focus volume. However, the extremely high instantaneous light intensities of femtosecond pulses in the focal volume dramatically increase the probability of further stepwise resonant photon absorption, leading to highly excited, ionizable and reactive states, often resulting in fast bleaching of fluorescent proteins in TPLSM. Here, we show that the femtosecond multiphoton excitation of red FPs (DsRed2 and mFruits), both in solution and live cells, results in a chain of consecutive, partially reversible reactions, with individual rates driven by a high-order (3-5 photon) absorption. The first step of this process corresponds to a three- (DsRed2) or four-photon (mFruits) induced fast isomerization of the chromophore, yielding intermediate fluorescent forms, which then subsequently transform into nonfluorescent products. Our experimental data and model calculations are consistent with a mechanism in which ultrafast electron transfer from the chromophore to a neighboring positively charged amino acid residue triggers the first step of multiphoton chromophore transformations in DsRed2 and mFruits, consisting of decarboxylation of a nearby deprotonated glutamic acid residue.

Prenatal and perinatal risk factors in a twin study of autism spectrum disorders

INTRODUCTION

Multiple studies associate prenatal and perinatal complications with increased risks for autism spectrum disorders (ASDs). The objectives of this study were to utilize a twin study design to 1) Investigate whether shared gestational and perinatal factors increase concordance for ASDs in twins, 2) Determine whether individual neonatal factors are associated with the presence of ASDs in twins, and 3) Explore whether associated factors may influence males and females differently.

METHODS

Data from medical records and parent response questionnaires from 194 twin pairs, in which at least one twin had an ASD, were analyzed.

RESULTS

Shared factors including parental age, prenatal use of medications, uterine bleeding, and prematurity did not increase concordance risks for ASDs in twins. Among the individual factors, respiratory distress demonstrated the strongest association with increased risk for ASDs in the group as a whole (OR 2.11, 95% CI 1.27-3.51). Furthermore, respiratory distress (OR 2.29, 95% CI 1.12-4.67) and other markers of hypoxia (OR 1.99, 95% CI 1.04-3.80) were associated with increased risks for ASDs in males, while jaundice was associated with an increased risk for ASDs in females (OR 2.94, 95% CI 1.28-6.74).

CONCLUSIONS

Perinatal factors associated with respiratory distress and other markers of hypoxia appear to increase risk for autism in a subgroup of twins. Future studies examining potential gender differences and additional prenatal, perinatal and postnatal environmental factors are required for elucidating the etiology of ASDs and suggesting new methods for treatment and prevention.

The effect of interventions to prevent and treat malnutrition in patients admitted for rehabilitation: a systematic review with meta-analysis

BACKGROUND

Malnutrition occurs frequently among patients in rehabilitation, leading to poorer outcomes. Evidence of the effects of interventions to prevent or treat malnutrition is required to guide clinical practice in this setting. This systematic review aimed to determine the effect of oral nutrition interventions implemented in rehabilitation on nutritional and functional outcomes.

METHODS

Five databases were searched to identify relevant publications; intervention trials of oral nutrition interventions (such as oral nutrition supplements, foodservice interventions, clinical care processes, enhanced eating environments) conducted with patients admitted for rehabilitation, reporting dietary intake, anthropometric, biochemical or functional outcomes. The reviewers determined study eligibility and assessed the included studies for risk of bias. Outcome data were combined narratively and by meta-analyses.

RESULTS

From 1765 publications, 10 studies trialling oral nutrition supplements, foodservice interventions and clinical care processes (of neutral or positive quality) were identified. Compared to meals alone, oral nutritional supplements significantly improved energy and protein intake, with some evidence for improvements in anthropometry and length of stay. There was little evidence that speciality supplements were beneficial compared to standard versions. Meta-analyses demonstrated significantly greater energy [weighted mean difference (WMD) = 324 kcal, 212-436 kcal 95% confidence interval (CI)] and protein (WMD = 9.1 g, 0.2-17.9 g 95% CI) intake with energy dense meals. Opposing results were reported in studies investigating enhanced clinical care processes.

CONCLUSIONS

The provision of oral nutrition supplements and energy dense meals improved energy and protein intake and therefore may comprise effective strategies for addressing malnutrition in rehabilitation. The effect of these strategies on other nutritional and functional outcomes should be explored further.

Role of lysine dimethylation in Bcl-2 function and T cell activation (LYM4P.744)

Bcl-2 is an anti-apoptotic protein that can protect developing and mature T cells from apoptosis. Interaction between anti-apoptotic and pro-apoptotic members of Bcl-2 family proteins is a key event in the regulation of apoptosis. Using mass spectroscopy to analyze a murine T cell line, we identified dimethylation of two lysine residues, K17 and K22, in the BH4 domain of Bcl-2, a domain critical for its anti-apoptotic function. Mutation of K22 (but not K17) to alanine abrogated Bcl-2 binding to pro-apoptotic proteins and greatly reduced Bcl-2 anti-apoptotic function in cytokine withdrawal. This assigns functional importance to K22, which is conserved across species and other anti-apoptotic members, and suggests that dimethylation could affect its function. Structure model of Bcl-2 was generated using computer simulation. The Bcl-2 model showed that the K22 appears to be involved in stabilizing peptide secondary structure, rather than directly interacting with pro-apoptotic proteins. With our newly developed monoclonal antibody to detect the K22 dimethylation of Bcl-2, dimethylated Bcl-2 was found in murine T and B cells, but not in thymocytes. There is no evidence that the dimethylation of Bcl-2 is regulated by IL-7, a growth factor required for T cell development and homeostasis. Anti-CD3 stimulation abolished Bcl-2 dimethylation in CD4 or CD8 cells. This suggests that Bcl-2 dimethylation may regulate activated T cell apoptosis but not be involved in thymic development.