Microglial control of astrocytes in response to microbial metabolites

Microglia and astrocytes modulate inflammation and neurodegeneration in the central nervous system (CNS)^1-3. Microglia modulate pro-inflammatory and neurotoxic activities in astrocytes, but the mechanisms involved are not completely understood^4,5. Here we report that TGFα and VEGF-B produced by microglia regulate the pathogenic activities of astrocytes in the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis. Microglia-derived TGFα acts via the ErbB1 receptor in astrocytes to limit their pathogenic activities and EAE development. Conversely, microglial VEGF-B triggers FLT-1 signalling in astrocytes and worsens EAE. VEGF-B and TGFα also participate in the microglial control of human astrocytes. Furthermore, expression of TGFα and VEGF-B in CD14⁺ cells correlates with the multiple sclerosis lesion stage. Finally, metabolites of dietary tryptophan produced by the commensal flora control microglial activation and TGFα and VEGF-B production, modulating the transcriptional program of astrocytes and CNS inflammation through a mechanism mediated by the aryl hydrocarbon receptor. In summary, we identified positive and negative regulators that mediate the microglial control of astrocytes. Moreover, these findings define a pathway through which microbial metabolites limit pathogenic activities of microglia and astrocytes, and suppress CNS inflammation. This pathway may guide new therapies for multiple sclerosis and other neurological disorders.

Genotypes, phenotypes and whole genome sequence: Approaches from the My Life Our Future haemophilia project

INTRODUCTION

Information from the genes encoding factor VIII (F8) and IX (F9) is used in reproductive planning and to inform inhibitor formation, bleeding severity and response to therapies. Advances in technology and our understanding of the human genome now allows more comprehensive methods to study genomic variation and its impact on haemophilia.

AIMS

The My Life Our Future (MLOF) programme was begun in 2012 to provide genetic analysis and to expand research in haemophilia through a research repository.

METHODS

MLOF enrolled haemophilia A and B patients followed at haemophilia treatment centers in the U.S., including, since 2015, known and potential genetic carriers. Initial F8 and F9 DNA analysis was performed utilizing a next generation sequencing approach which allowed simultaneous detection of F8 inversions and other variants. Candidate variants were confirmed using a second method and multiplex ligation-dependent probe amplification was used to detect structural variants.

RESULTS

The initial phase of MLOF completed enrollment in December 2017 with 11,356 patients, genetic carriers, and potential carriers enrolled. In the 9453 subjects in whom analysis is complete, 687 unique previously unreported variants were found. Simultaneous sequencing of the F8 and F9 genes resulted in identification of non-deleterious variants previously reported as causative in haemophilia. DNA from 5141 MLOF subjects has undergone whole genome sequencing through the NHLBI TOPMed programme of the U.S. NIH.

CONCLUSION

MLOF has provided genetic information for patients and their families to help inform clinical care and has established a repository of data and biospecimens to further advance haemophilia research.

Looking after the mouth - Evaluation of a pilot for a new approach to training care home carers in Kent, Surrey and Sussex

Objective This pilot study aimed to produce and evaluate training resources and training in oral health care, including oral hygiene, for carers in care homes in Surrey and Medway.Methods During two training days, for carers from these homes, short, interactive presentations were given on a range of topics relevant to oral health care and oral hygiene of older people, followed by practical training. Prior to any training all attendees completed a 39 question questionnaire to establish their baseline knowledge of oral health and hygiene. At the end of the training day they completed an evaluation form. Fourteen weeks later, they were visited at their place of work and completed the same questionnaire again. Differences in responses between baseline and after 14 weeks were statistically tested using the chi-squared test.Results Sixty-six carers attended the training sessions and 44 were followed up 14 weeks later. The results showed an improvement in carer knowledge at follow up. The majority of carers (36/44) spoke English as their first language. They had a mean age of 41 years, 37 were female and 7 male. They had worked as carers for a mean of 10.9 years (range 4 months-34 years). Over 90% stated that the training day fully met or exceeded their requirements and expectations.Conclusions The results indicated improvements in carer knowledge. However, the carers were atypical of carers in general, as they were self-selected and well-motivated. Nevertheless the content of the training day and the questionnaire should inform future work in this area.

155 Oocyte Maturation in Lyophilized In Vitro Maturation Medium as a Method to Increase the Medium’s Shelf-Life

The in vitro production of bovine embryos has dramatically increased in recent years, and with it the demand of stable media with a long shelf-life. In this experiment we evaluated the impact of the freeze-dried in vitro maturation (IVM) medium (Mdry) on in vitro oocyte maturation. We compared the standard IVM and the Mdry media. Medium M199 was used as base for the IVM medium. The percentage of metaphase II oocytes and embryo production were evaluated. Media solutions (10 mL) were aliquoted into 50-mL conical tubes and lyophilized to form a powder concentrate using a Genesis freeze-dryer (VirTis, Gardener, NY, USA). Lyophilization consisted of a constant cooling from 20°C to –10°C at a constant rate of 1°C/min with a 2-h hold at –10°C before sublimation at 0°C. The Mdry medium was held at –80°C for 4 months (only serum and hormones were added before the incubation). When the IVM medium was rehydrated, the pH were adjusted to 7.4. The percentage of mature oocytes was evaluated after 24 h of maturation. The oocytes were stained with Hoechst 33342, and only oocytes with metaphase and a polar body were evaluated as matured. Abattoir-derived Holstein oocytes (n = 540) were in vitro matured (25–30/well in 400 µL) and fertilized with sexed semen, according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). The oocytes were split for analysis (432 were used for IVP and 108 for maturation rate) over 6 replicates. Twenty hours after IVF, presumptive zygotes were cultured in SOF medium at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed. All recorded parameters were subjected to a Student’s t-test. The parameters compared were maturation rate, cleavage rate, blastocyst rate and the percentage of embryos cleaved. The α level was set at 0.05. All data were expressed as quadratic means and mean standard deviations. The results showed no differences between the 2 groups (75.9% v. 74.1%) (t = 0.37; SD = 12.69; P = 0.36; df = 5) when we compared the nuclear maturation; however, when we evaluated embryo production, we found the Mdry treatment had a higher cleavage percentage (t = 2.39; SD = 14.81; P = 0.02; df = 5) and total embryos produced (t = 2.49; SD = 5.6; P = 0.02; df = 5) compared with the control (Table 1.). These results showed that lyophilization can be a valid method to increase the shelf life of IVP media. More replicates must be done in order to understand why the freeze-dried media produced more embryos. Table 1.Mean (SD in parentheses) percentage cleavage and blastocysts

123 In Vitro Embryo Production in Lyophilized In Vitro Culture Medium as a Method to Increase the Medium's Shelf-Life

The worldwide production of livestock embryos requires stable medium with long shelf life. In this experiment, we evaluated the impact of the freeze-dried in vitro culture (IVC) medium (Mdry) on in vitro embryo production. We compared the standard IVC and Mdry media for cleavage rate and embryo production. Media solutions (10 mL) were aliquoted into 50-mL conical tubes and lyophilized to form a powder concentrate using a Genesis freeze-dryer (VirTis, Gardener, NY, USA). Lyophilization consisted of a constant cooling from 20°C to –10°C at a constant rate of 1°C/min with a 2-h hold at –10°C before sublimation at 0°C. Mdry medium were held at –80°C for 4 months. When the IVC medium was rehydrated, the pH were adjusted to 7.4. Abattoir-derived Holstein oocytes (n = 618, in 7 replicates) were in vitro matured and fertilized with sexed semen, according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). Twenty hours after IVF, presumptive zygotes were cultured in SOF medium with 5% BS at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed. All recorded parameters were subjected to a Chi-Square Test 2 × 2. The parameters compared were percent cleavage, blastocysts, and embryos/cleaved. The α level was set at 0.05. All data were expressed as quadratic means and mean standard errors. The results (Table 1) showed not a statistical difference between control and Mdry. The Mdry had a higher percentage of cleaved zygotes (65.4% v. 53.4%) but not enough for a statistical difference. However, when we compared embryo production, there was no difference between treatments. The ratio between blastocysts and cleaved embryos was higher in the control group but not significant according to our selected α level. These results indicate that it is possible lyophilize IVC medium without interfering with the potential quality of the medium. Further studies will be needed to better understand the positive effect of the lyophilization on the cleavage rate. Table 1.Mean (SD in parentheses) percentage cleavage and blastocysts

Assessment of Mixed-Layer Height Estimation from Single-wavelength Ceilometer Profiles

Differing boundary/mixed-layer height measurement methods were assessed in moderately-polluted and clean environments, with a focus on the Vaisala CL51 ceilometer. This intercomparison was performed as part of ongoing measurements at the Chemistry And Physics of the Atmospheric Boundary Layer Experiment (CAPABLE) site in Hampton, Virginia and during the 2014 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign that took place in and around Denver, Colorado. We analyzed CL51 data that were collected via two different methods (BLView software, which applied correction factors, and simple terminal emulation logging) to determine the impact of data collection methodology. Further, we evaluated the STRucture of the ATmosphere (STRAT) algorithm as an open-source alternative to BLView (note that the current work presents an evaluation of the BLView and STRAT algorithms and does not intend to act as a validation of either). Filtering criteria were defined according to the change in mixed-layer height (MLH) distributions for each instrument and algorithm and were applied throughout the analysis to remove high-frequency fluctuations from the MLH retrievals. Of primary interest was determining how the different data-collection methodologies and algorithms compare to each other and to radiosonde-derived boundary-layer heights when deployed as part of a larger instrument network. We determined that data-collection methodology is not as important as the processing algorithm and that much of the algorithm differences might be driven by impacts of local meteorology and precipitation events that pose algorithm difficulties. The results of this study show that a common processing algorithm is necessary for LIght Detection And Ranging (LIDAR)-based MLH intercomparisons, and ceilometer-network operation and that sonde-derived boundary layer heights are higher (10-15% at mid-day) than LIDAR-derived mixed-layer heights. We show that averaging the retrieved MLH to 1-hour resolution (an appropriate time scale for a priori data model initialization) significantly improved correlation between differing instruments and differing algorithms.

140 COMPARISON OF 3 DIFFERENT METHODS TO SELECT HIGH SPERM QUALITY FOR IVF

Sperm selection is a fundamental step for IVF, influencing treatment and the health of offspring. Over the years, several techniques have been tested to recover highly motile sperm, including centrifugation with discontinuous gradients and numerous filtration procedures. In our previous paper, we showed that it is possible, in ~20 min, to select a high quality sperm population using an electric charge in a microchannel device. This method produced the same blastocyst rates as a discontinuous gradient (DG), but in less time [25 min less; Rubessa et al. 2016 Andrology (Los Angeles) 5]. This technique takes advantage of one of the physiological characteristics of high quality sperm; that is, the head has a negative electric charge. The aim of the present experiment was to analyse the characteristics of the sperm selected with our device. We compared 2 standard sperm procedures and our device, with semen assessed using a computer-assisted sperm analyzer to evaluate the principal sperm parameters. Standard procedures were used to select sperm by DG and swim-up (SU). Thawed semen was pipetted into the microchannel of our device and then exposed to the electric charge (10 V) for 10 min [Rubessa et al. 2016 Andrology (Los Angeles) 5]. For each replicate, 3 straws of frozen bovine semen were thawed at 37°C for 40 s and pooled. The pooled sample was divided into 3 aliquots: one for each technique, 5 replicates of the experiment were performed. Data were analysed by ANOVA using the general linear model (GLM) procedure (SPSS Inc., Chicago, IL, USA). Bonferroni’s post hoc test was used to perform statistical multiple comparison. The α-level was set at 0.05. The results show an effect of the method all motility parameters are not significantly different, although some of the motility parameters were statistically different (P < 0.05). (P < 0.05). The beat cross frequency results were 23 ± 2.4 v. 37.7 ± 2.1 v. 19.5 ± 0.7 (µm/s) for DG, SU, and EC. The same statistical differences were found for the STR (straightness): 75 ± 3.5 v. 84.5 ± 2.0 v. 62.3 ± 2.4 (µm/s), and LIN (linearity): 39.8 ± 4.4 v. 53 ± 1.2 and 31.8 ± 1.4. These results confirmed the potential of this new device, and that it is possible to use this new method to select high motility sperm without harming sperm characteristics. These results showed that our device produced the same quality of sperm obtained with DG and SU but in as little as 20 min.

New Roles of Syntaxin-1A in Insulin Granule Exocytosis and Replenishment

In type-2 diabetes (T2D), severely reduced islet syntaxin-1A (Syn-1A) levels contribute to insulin secretory deficiency. We generated β-cell-specific Syn-1A-KO (Syn-1A-βKO) mice to mimic β-cell Syn-1A deficiency in T2D. Glucose tolerance tests showed that Syn-1A-βKO mice exhibited blood glucose elevation corresponding to reduced blood insulin levels. Perifusion of Syn-1A-βKO islets showed impaired first- and second-phase glucose-stimulated insulin secretion (GSIS) resulting from reduction in readily releasable pool and granule pool refilling. To unequivocally determine the β-cell exocytotic defects caused by Syn-1A deletion, EM and total internal reflection fluorescence microscopy showed that Syn-1A-KO β-cells had a severe reduction in the number of secretory granules (SGs) docked onto the plasma membrane (PM) at rest and reduced SG recruitment to the PM after glucose stimulation, the latter indicating defects in replenishment of releasable pools required to sustain second-phase GSIS. Whereas reduced predocked SG fusion accounted for reduced first-phase GSIS, selective reduction of exocytosis of short-dock (but not no-dock) newcomer SGs accounted for the reduced second-phase GSIS. These Syn-1A actions on newcomer SGs were partly mediated by Syn-1A interactions with newcomer SG VAMP8.

Acute effects of breaking up prolonged sitting on fatigue and cognition: a pilot study

OBJECTIVES

To compare the acute effects of uninterrupted sitting with sitting interrupted by brief bouts of light-intensity walking on self-reported fatigue, cognition, neuroendocrine biomarkers and cardiometabolic risk markers in overweight/obese adults.

DESIGN

Randomised two-condition crossover trial.

SETTING

Laboratory study conducted in Melbourne, Australia.

PARTICIPANTS

19 overweight/obese adults (45-75 years).

INTERVENTIONS

After an initial 2 h period seated, participants consumed a meal-replacement beverage and completed (on 2 days separated by a 6-day washout period) each condition over the next 5 h: uninterrupted sitting (sedentary condition) or sitting with 3 min bouts of light-intensity walking every 30 min (active condition).

PRIMARY OUTCOME MEASURES

Self-reported fatigue, executive function and episodic memory at 0 h, 4 h and 7 h.

SECONDARY OUTCOME MEASURES

Neuroendocrine biomarkers and cardiometabolic risk markers (blood collections at 0 h, 4 h and 7 h, blood pressure and heart rate measured hourly and interstitial glucose measured using a continuous glucose monitoring system).

RESULTS

During the active condition, fatigue levels were lower at 4 h (-13.32 (95% CI -23.48 to -3.16)) and at 7 h (-10.73 (95% CI -20.89 to -0.58)) compared to the sedentary condition. Heart rate was higher at 4 h (4.47 (95% CI 8.37 to 0.58)) and at 7 h (4.32 (95% CI 8.21 to 0.42)) during the active condition compared to the sedentary condition. There were no significant differences between conditions by time for other variables. In the sedentary condition, changes in fatigue scores over time correlated with a decrease in heart rate and plasma dihydroxyphenylalanine (DOPA) and an increase in plasma dihydroxyphenylglycol (DHPG).

CONCLUSIONS

Interrupting prolonged sitting with light-intensity walking breaks may be an effective fatigue countermeasure acutely. Fatigue levels corresponded with the heart rate and neuroendocrine biomarker changes in uninterrupted sitting in this pilot study. Further research is needed to identify potential implications, particularly for the occupational health context.

TRIAL REGISTRATION NUMBER

ACTRN12613000137796; Results.

244 CHONDROGENIC PELLET CULTURES FOR CARTILAGE TISSUE ENGINEERING GROW BY DEPOSITION OF MATRIX AND NOT BY CELLULAR PROLIFERATION

Pellet cultures are commonly used to study chondrogenic differentiation in vitro. Our laboratory has demonstrated pellets made with chondrocytes grow in size during culture and produce cartilage matrix, but pellets made with adipose-derived mesenchymal stem cells (ASC) grow only slightly, producing little cartilage matrix. The objective of this study was to determine if differences in chondrocyte and ASC pellet growth result from differences in cell proliferation or in deposition of extracellular matrix. Primary chondrocytes and ASC from adult pigs were cultured in Dulbecco’s modified Eagle’s medium (DMEM) with 10% fetal bovine serum. To determine baseline proliferation rates in monolayer culture, cells were grown on coverslips in 10 µM bromodeoxyuridine (BrdU) for 24 h and immunostained for BrdU labelling. For pellet cultures, 5 × 105 cells were placed in 15 mL-conical tubes, pelleted by centrifugation in 1.0 mL of chondrogenic base media (CBM: DMEM + 40 µg mL–1 of proline, 50 µM ascorbic acid-2-phosphate, 100 nM dexamethasone, and 1× insulin-transferrin-selenium), and cultured in CBM for 1, and 4 weeks. To detect proliferation in pellets, 1- and 2-week cultured samples were labelled with 10 µM BrdU for 24 h before harvest. Pellets were fixed with 4% paraformaldehyde, embedded, and sectioned on a Leica CM1900 cryostat (Leica Microsystems, Wetzlar, Germany). To assess chondrogenic differentiation and matrix expression, sections were stained for collagen II, keratin sulfate, and chondroitin sulfate. Images were captured and distance between adjacent nuclei in 1- and 4-week pellets were measured using Zeiss imaging software. As expected, cells on coverslips showed BrdU labelling, with higher labelling in ASC cultures indicating faster proliferation (n = 5, 77.3 ± 3.74% chondrocyte v. 92.1 ± 2.88% ASC; α = 0.05; P < 0.0001; Student’s t-test). However, BrdU labelling was not seen in sections from ASC or chondrocyte pellets (n = 5), at either 1 or 2 weeks. Absence of cellular proliferation in pellets was verified by negative staining for the mitotic marker Aurora KinaseB (AurKB). Cartilage matrix staining was strong in chondrocyte pellets at all time points and absent in ASC pellets. Cell nuclei were closely packed in both ASC and chondrocyte pellets at 1 week, but a significant increase in distance between adjacent nuclei with interspersed matrix staining was noted in chondrocyte pellets at 4 weeks (n = 4, 11.88 ± 0.67 µm at 1 week v. 26.85 ± 2.06 µm at 4 weeks; α = 0.05; P < 0.0001; Student’s t-test). As TGFβ3 has been shown to induce chondrogenesis in ASC, ASC pellets were cultured in CBM + 10 ng of TGFβ3 for 1 and 2 weeks (n = 4). The TGFβ3 treatment did not induce cell proliferation in pellets, as sections were negative for BrdU. However, expression of cartilage markers keratan sulfate and chondroitin were noted. Based on our data, neither ASC nor chondrocytes proliferate in pellet culture, and chondrocyte pellet growth is due to extracellular matrix deposition.

245 RISK OF TRANSMISSION OF BOVINE LEUKOSIS VIRUS (BLV) USING SEROPOSITIVE BULLS FOR IN VITRO FERTILIZATION EMBRYO PRODUCTION

Bovine leukosis virus (BLV) is a pathogen that affects the bovine immune system and leads to lymphosarcoma, leukemia, decreased milk production, and increased culling rates in cattle. BLV-infected cattle herds can be found worldwide; in the United States, specifically, 38% of beef herds, 84% of all dairy herds, and 100% of large-scale dairy operation herds are infected (Buehring et al. 2014 Emerg. Infect. Dis. 5, 772–782). The main transmission between cattle in herds is affected leukocytes in blood. Several farm practices, such as dehorning, rectal palpation, and vaccinating can lead to the pathogen transmission. Due to international trade laws and biosecurity concerns, semen from a BLV-positive bull is illegal to sell within certain countries. Prior studies have looked at use of seropositive bulls in AI with little risk in affecting the dam (Burger et al. 2000 AVJR 60, 819). Other studies used semen that was artificially infected with the virus then used for IVF (Bielanski et al. 2000 Vet. Rec. 146, 255–256). The aim of this research was to evaluate naturally infected BLV donor semen using abattoir-derived oocytes and the possible contamination of in vitro-produced (IVP) embryos. Semen was collected and frozen by a private company. Three seropositive bulls and 1 negative control bull were selected. All positive bulls were selected based on availability of seropositive BLV status. Prior to the experiment, all bulls used were evaluated for motility, concentration, and morphology. The negative control was used in prior IVF experiments that produced acceptable results for use in this experiment. Frozen sperm were thawed at 37°C for 40 s and pelleted by centrifugation (25 min at 300 × g) on a Percoll discontinuous gradient (45–80% in Tyrode’s modified medium without glucose and BSA). The matured oocytes were purchased from DeSoto Biosciences (Seymour, TN, USA) and were IVF according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347–1355). Using 200 oocytes per replicate, the 3 positive bulls and 1 control bull were allocated 50 oocytes per bull in each replicate. After 20 to 22 h of gametes co-incubation, zygotes were denuded and cultured for 7 days in SOF, followed by the evaluation of embryos (from tight morula until hatching blastocyst). Positive bull #1 produced and tested 48 embryos. Positive bull #2 produced and tested 41 embryos. Positive bull #3 produced and tested 46 embryos. The negative control produced and tested 55 embryos. Embryonic DNA extraction was performed using standard procedures (Sattar et al. 2011 Reprod. Domest. Anim. 46, 1090–1097). Nested PCR followed the Fechner evaluations methods (Fechner et al. 1996 J. Vet. Med. B 43, 621–630). To detect BLV presence, electrophoresis was used with a 2% agarose gel containing 0.1% ethidium bromide. A total of 190 embryos were evaluated that were produced in 3 replicates. All samples analysed showed no evidence of BLV. In conclusion, use of BLV seropositive donor semen showed no transmission of the virus upon IVF of the oocytes.

Outcomes after heart transplantation for amyloid cardiomyopathy in the modern era

We conducted a review of patients undergoing heart transplantation (HT) at our institution for amyloid cardiomyopathy (ACM) between 2008 and 2013. Complete follow-up was available for all patients. Nineteen patients with ACM underwent HT during the study period, accounting for 9.4% of all HT performed at our institution during this period. Amyloid subtype was light chain (AL) in 9 patients and transthyretin (ATTR) in 10 (2 wild-type, 7 familial, 1 unknown). Eight of nine patients with AL amyloidosis began chemotherapy prior to HT, six have resumed chemotherapy since HT, and five have undergone autologous stem cell transplantation. Most recent free light chain levels in AL patients decreased by a median of 85% from peak values. Only one patient developed recurrent graft amyloidosis, occurring at 3.5 years post-HT and asymptomatic. After a median follow-up of 380 days, 17 (89.5%) patients are alive. To our knowledge, this is the largest single-center series reported of ACM patients undergoing HT in the modern era. Our results suggest that acceptable outcomes following HT can be achieved in the short-to-intermediate term and that this is a feasible option for end-stage ACM with careful patient selection and aggressive control of amyloidogenic light chains in AL patients.