O1: DISCOVERING NOVEL THERAPEUTICS TO TREAT ACUTE TRAUMATIC COAGULOPATHY (ATC)

Introduction

In the UK, 17,000 people die from injury each year, with uncontrolled bleeding the most significant cause of preventable mortality. Acute Traumatic Coagulopathy (ATC) exacerbates bleeding through the failure of blood-clotting with accelerated clot breakdown that mechanistically is driven by activated Protein C (aPC). No targeted therapy to treat the underlying cause of ATC exists with treatment limited to blood component resuscitation and antifibrinolytic drugs to prevent premature clot breakdown.

Method

Two hundred fifty-four bleeding trauma patients had Factor V and aPC measured on arrival and during resuscitation. A preclinical ATC model was used to test the novel therapeutic recombinant Factor V (rFV), which is resistant to aPC mediated cleavage. Mice underwent combined injury and pressure controlled-blood loss with intervention at 30-minutes to represent a clinically relevant model. Coagulopathy was measured by ROTEM and biomarkers of coagulation/fibrinolysis.

Result

Admission levels of FV were 38% lower (83 vs 134u/dL, p<0.0001), deteriorated during resuscitation to 65% of normal after transfusion of eight RBC units and were inversely related to aPC levels. Compared to vehicle, animals treated with rFV had reduced coagulopathy (Clot Strength at 5 minutes: 31 vs 24mm, p<0.01) and significantly improved survival (80% vs 44%, p≤ 0.001).

Conclusion

FV falls significantly during bleeding in trauma patients and in the murine model, rFV improved coagulation suggesting it may represent a potential therapeutic target for ATC.

Take-home message

Directly targeting the cause of ATC represents a novel therapeutic strategy in trauma and may improve survival after major haemorrhage by directly improving clot function.

In vivo PET imaging of the neuroinflammatory response in rat spinal cord injury using the TSPO tracer [(18)F]GE-180 and effect of docosahexaenoic acid

Purpose

Traumatic spinal cord injury (SCI) is a devastating condition which affects millions of people worldwide causing major disability and substantial socioeconomic burden. There are currently no effective treatments. Modulating the neuroinflammatory (NI) response after SCI has evolved as a major therapeutic strategy. PET can be used to detect the upregulation of the 18-kDa translocator protein (TSPO), a hallmark of activated microglia in the CNS. We investigated whether PET imaging using the novel TSPO tracer [¹⁸F]GE-180 can be used as a clinically relevant biomarker for NI in a contusion SCI rat model, and we present data on the modulation of NI by the lipid docosahexaenoic acid (DHA).

Methods

A total of 22 adult male Wistar rats were subjected to controlled spinal cord contusion at the T10 spinal cord level. Six non-injured and ten T10 laminectomy only (LAM) animals were used as controls. A subset of six SCI animals were treated with a single intravenous dose of 250 nmol/kg DHA (SCI-DHA group) 30 min after injury; a saline-injected group of six animals was used as an injection control. PET and CT imaging was carried out 7 days after injury using the [¹⁸F]GE-180 radiotracer. After imaging, the animals were killed and the spinal cord dissected out for biodistribution and autoradiography studies. In vivo data were correlated with ex vivo immunohistochemistry for TSPO.

Results

In vivo dynamic PET imaging revealed an increase in tracer uptake in the spinal cord of the SCI animals compared with the non-injured and LAM animals from 35 min after injection (P < 0.0001; SCI vs. LAM vs. non-injured). Biodistribution and autoradiography studies confirmed the high affinity and specific [¹⁸F]GE-180 binding in the injured spinal cord compared with the binding in the control groups. Furthermore, they also showed decreased tracer uptake in the T10 SCI area in relation to the non-injured remainder of the spinal cord in the SCI-DHA group compared with the SCI-saline group (P < 0.05), supporting a NI modulatory effect of DHA. Immunohistochemistry showed a high level of TSPO expression (38 %) at the T10 injury site in SCI animals compared with that in the non-injured animals (6 %).

Conclusion

[¹⁸F]GE-180 PET imaging can reveal areas of increased TSPO expression that can be visualized and quantified in vivo after SCI, offering a minimally invasive approach to the monitoring of NI in SCI models and providing a translatable clinical readout for the testing of new therapies.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-016-3391-8) contains supplementary material, which is available to authorized users.

Imaging of the vulnerable carotid plaque: biological targeting of inflammation in atherosclerosis using iron oxide particles and MRI

OBJECTIVES

Identification of those patients with high-risk asymptomatic carotid plaques remains an elusive but essential step in stroke prevention. Inflammation is a key process in plaque destabilization and the propensity of atherosclerotic lesions to cause clinical sequelae. There is currently no clinical imaging technique available to assess the degree of inflammation associated with plaques. This study aims at visualizing and characterizing atherosclerosis using antibody-conjugated superparamagnetic iron oxide (SPIO) particles as an MRI probe to assess inflammation in human atherosclerotic plaques.

METHODS

Atherosclerotic plaques were collected from 20 consecutive patients (n=10 from symptomatic patients, n=10 from asymptomatic patients) undergoing carotid endarterectomy (CEA) for extracranial high-grade internal carotid artery (ICA) stenosis (>70% luminal narrowing). Inflammatory markers on human atherosclerotic plaques were detected and characterized by ex vivo magnetic resonance imaging (MRI) using anti-VCAM-1 antibody and anti-E-selectin antibody-conjugated SPIO with confirmatory immunohistochemistry.

RESULTS

Inflammation associated with human ex vivo atherosclerotic plaques could be imaged using dual antibody-conjugated SPIO by MRI. Symptomatic plaques could be distinguished from asymptomatic ones by the degree of inflammation, and the MR contrast effect was significantly correlated with the degree of plaque inflammation (r=.64, p<.001). The asymptomatic plaque population exhibited heterogeneity in terms of inflammation. The dual-targeted SPIO-induced MR signal not only tracked closely with endothelial activation (i.e. endothelial expression of VCAM-1 and E-selectin), but also reflected the macrophage burden within plaque lesions, offering a potential imaging tool for quantitative MRI of inflammatory activity in atherosclerosis.

CONCLUSIONS

These functional molecular MRI probes constitute a novel imaging tool for ex vivo characterization of atherosclerosis at a molecular level. Further development and translation into the clinical arena will facilitate more accurate risk stratification in carotid artery disease in the future.

Lasting effects of chronic fluoxetine treatment on the late developing rat brain: age-dependent changes in the serotonergic neurotransmitter system assessed by pharmacological MRI

RATIONALE

With the growing prevalence of psychotropic drug prescriptions among children and adolescents, the need for studies on lasting effects of drug exposure on the developing brain rises. Fluoxetine is the only selective serotonin reuptake inhibitor (SSRI) officially registered to treat major depressive disorder in children. Although various (pre)clinical studies have assessed the (long-term) effects of fluoxetine exposure in the perinatal period and in adulthood, limited data is available on its effects on the developing brain later in life, i.e. during adolescence.

OBJECTIVE

The present study aimed at investigating the effects of age following chronic SSRI treatment on the central serotonin (5-HT) system. To this end, pharmacological MRI (phMRI) was performed in chronic fluoxetine-treated (5 mg/kg, oral gavage for 3 weeks) juvenile (PND25) and adult rats (PND65) after a 1-week washout period, using an acute fluoxetine challenge (5 mg/kg, i.v.) to trigger the 5-HT system.

RESULTS

We observed a diminished brain response to the acute challenge in adult treated animals when compared to control animals, whereas this response was increased in juvenile treated rats. As a result, a significant age by treatment interaction effect was seen in several (subcortical) 5-HT related brain regions.

CONCLUSION

An opposite effect of chronic fluoxetine treatment was seen in the developing brain compared to that in matured brain, as assessed non-invasively using phMRI. These findings most likely reflect neuronal imprinting effects of juvenile SSRI treatment and may underlie emotional disturbances seen in animals and children treated with this drug. Also, our findings suggest that phMRI might be ideally suited to study this important issue in the pediatric population.

Evaluation of viability and apoptosis in horse embryos stored under different conditions at 5 degrees C

The aim of this study was to evaluate the viability (percentage of dead cells) and the incidence of DNA fragmentation of horse embryos after storage in three different media at 5 degrees C for 6 and 24 h. Forty embryos were stored in Emcare Holding Solution for 6 and 24 h, in Hams'F10 or Vigro Holding Plus for 24 h at 5 degrees C (n = 9-10 per group) and 10 embryos were evaluated immediately after collection. First, embryos were stained, immediately after collection or following storage, to detect dead cells (DAPI) and, subsequently, DAPI-stained embryos were fixed and stained to detect DNA fragmentation (TUNEL). Finally, all the fixed embryos were re-stained with DAPI to determine the total number of cells. The percentage of cells stained with both TUNEL and DAPI or TUNEL-only or DAPI-only were determined. The percent of dead cells (DAPI-labelled) per embryo increased with duration of storage, but no differences were detected between the storage media. The percentage of early apoptotic cells (TUNEL+/DAPI-) in fresh and stored embryo for 6 h or 24 h did not differ significantly (P > 0.05). There was a significant correlation between the percentage of cells labelled by TUNEL and DAPI (R = 0.87) (P < 0.001). These results suggest that cooled storage increases cell death but this does not appear to occur by induction of apoptosis and that DAPI staining proves to be a quick and reliable method for assessing embryo viability.

Effect of the number of passages of fetal and adult fibroblasts on nuclear remodelling and first embryonic division in reconstructed horse oocytes after nuclear transfer

The effects of repeated passage in vitro of fetal fibroblast cells (FFC) and adult fibroblast cells (AFC) on nuclear remodelling and first embryonic division when used to reconstruct horse oocytes, and the reasons for the developmental block in progression to the two-cell stage were investigated. A total of 463 metaphase II oocytes produced 427 fibroblast-cytoplasm couplets after nuclear transfer, which finally resulted in 319 reconstructed oocytes. With increasing numbers of passages, the rates of nuclear remodelling decreased in both types of donor cell; about half of the fused donor cell nuclei showed the S-G2-prometaphase stages of the first embryonic division 18-20 h after cell-fusion treatment, irrespective of the number of donor cell passages (FFC: 49%; AFC: 53%). The rates of first embryonic division in the reconstructed oocytes fell with increasing age of the donor cells (FFC: 32%-26%-23%; AFC: 27%-23%-24%) and these rates were significantly lower than those obtained from metaphase II oocytes activated parthenogenetically (79%, P < 0.05). Microscopic analysis of the organization of the first embryonic division in the developmentally blocked oocytes reconstructed with either FFC or AFC showed that most of these (FFC: 78%; AFC: 92%) could not form the mitotic spindle and the metaphase plate of chromosomes. These findings indicate that either fetal or adult fibroblasts that have undergone relatively few passages in vitro are most suitable as donors. However, both types of cell have lower potential to restart first embryonic development after nuclear transfer than do the equivalent cells in other species. Improvement in the rate of donor cell nuclear progression from S-G2-prometaphase to beyond the metaphase stage, and the normal organization of first embryonic development in reconstructed horse oocytes, would seem to be the key to the production of cloned embryos in this species.

Effects of follicular cells and FSH on the resumption of meiosis in equine oocytes matured in vitro

It has been suggested that preculturing immature oocytes in a manner that maintains them in meiotic arrest may improve cytoplasmic maturation and, thereby, the eventual developmental competence of oocytes matured in vitro. This study examined the ability of follicular cells to maintain meiotic arrest in equine oocytes. Cumulus-oocyte complexes (COCs) recovered from dead mares were cultured for 38 h in M199 either attached to, or together with, different follicle wall components, as follows: (1) attached to the follicle wall, (2) cocultured with separated follicle wall, (3) attached to membrana granulosa (COCG), (4) COCGs cocultured with sheets of theca cells, (5) COCGs cultured in theca-cell conditioned medium, and (6) control COCs without any follicle wall components. When oocytes were cultured attached to their follicle wall, 79% remained in the GV stage throughout the 38 h incubation. However, when oocytes were cocultured with separate pieces of follicle wall, meiosis resumed and a similar proportion of oocytes progressed to metaphase II (79%) as under control conditions (84%). Only 16% of oocytes cultured while still attached to the membrana granulosa (COCGs) maintained the GV stage, whereas when COCGs were cocultured with theca cells or in theca-cell conditioned medium, significantly more oocytes remained in the GV stage (64 and 52%, respectively), indicating that theca cells secrete a meiosis-inhibiting factor. The effect of FSH on the meiosis-inhibiting activity of follicular cells was investigated by culturing COCs attached to the follicle wall and COCGs in the presence or absence of theca cells in medium containing FSH. Addition of 0.05 iu recombinant human FSH ml(-1) to the culture medium did not affect nuclear maturation and failed to overcome the suppressive effect exerted by the follicle wall or by theca cells, despite the fact that mRNA for the FSH receptor was found using RT-PCR in both cumulus and granulosa cells. These results demonstrate that the maintenance of meiotic arrest in equine oocytes during culture can be promoted by theca cells, which appear to act via a secreted inhibitory factor that cannot be suppressed or counteracted by FSH.

Effect of the number of passages of fetal and adult fibroblasts on nuclear remodelling and first embryonic division in reconstructed horse oocytes after nuclear transfer

The effects of repeated passage in vitro of fetal fibroblast cells (FFC) and adult fibroblast cells (AFC) on nuclear remodelling and first embryonic division when used to reconstruct horse oocytes, and the reasons for the developmental block in progression to the two-cell stage were investigated. A total of 463 metaphase II oocytes produced 427 fibroblast-cytoplasm couplets after nuclear transfer, which finally resulted in 319 reconstructed oocytes. With increasing numbers of passages, the rates of nuclear remodelling decreased in both types of donor cell; about half of the fused donor cell nuclei showed the S-G2-prometaphase stages of the first embryonic division 18-20 h after cell-fusion treatment, irrespective of the number of donor cell passages (FFC: 49%; AFC: 53%). The rates of first embryonic division in the reconstructed oocytes fell with increasing age of the donor cells (FFC: 32%-26%-23%; AFC: 27%-23%-24%) and these rates were significantly lower than those obtained from metaphase II oocytes activated parthenogenetically (79%, P < 0.05). Microscopic analysis of the organization of the first embryonic division in the developmentally blocked oocytes reconstructed with either FFC or AFC showed that most of these (FFC: 78%; AFC: 92%) could not form the mitotic spindle and the metaphase plate of chromosomes. These findings indicate that either fetal or adult fibroblasts that have undergone relatively few passages in vitro are most suitable as donors. However, both types of cell have lower potential to restart first embryonic development after nuclear transfer than do the equivalent cells in other species. Improvement in the rate of donor cell nuclear progression from S-G2-prometaphase to beyond the metaphase stage, and the normal organization of first embryonic development in reconstructed horse oocytes, would seem to be the key to the production of cloned embryos in this species.

Effects of follicular cells and FSH on the resumption of meiosis in equine oocytes matured in vitro

It has been suggested that preculturing immature oocytes in a manner that maintains them in meiotic arrest may improve cytoplasmic maturation and, thereby, the eventual developmental competence of oocytes matured in vitro. This study examined the ability of follicular cells to maintain meiotic arrest in equine oocytes. Cumulus-oocyte complexes (COCs) recovered from dead mares were cultured for 38 h in M199 either attached to, or together with, different follicle wall components, as follows: (1) attached to the follicle wall, (2) cocultured with separated follicle wall, (3) attached to membrana granulosa (COCG), (4) COCGs cocultured with sheets of theca cells, (5) COCGs cultured in theca-cell conditioned medium, and (6) control COCs without any follicle wall components. When oocytes were cultured attached to their follicle wall, 79% remained in the GV stage throughout the 38 h incubation. However, when oocytes were cocultured with separate pieces of follicle wall, meiosis resumed and a similar proportion of oocytes progressed to metaphase II (79%) as under control conditions (84%). Only 16% of oocytes cultured while still attached to the membrana granulosa (COCGs) maintained the GV stage, whereas when COCGs were cocultured with theca cells or in theca-cell conditioned medium, significantly more oocytes remained in the GV stage (64 and 52%, respectively), indicating that theca cells secrete a meiosis-inhibiting factor. The effect of FSH on the meiosis-inhibiting activity of follicular cells was investigated by culturing COCs attached to the follicle wall and COCGs in the presence or absence of theca cells in medium containing FSH. Addition of 0.05 iu recombinant human FSH ml(-1) to the culture medium did not affect nuclear maturation and failed to overcome the suppressive effect exerted by the follicle wall or by theca cells, despite the fact that mRNA for the FSH receptor was found using RT-PCR in both cumulus and granulosa cells. These results demonstrate that the maintenance of meiotic arrest in equine oocytes during culture can be promoted by theca cells, which appear to act via a secreted inhibitory factor that cannot be suppressed or counteracted by FSH.

Organisation of the cytoskeleton during in vitro maturation of horse oocytes

Meiotic maturation of mammalian oocytes is a complex process during which microfilaments and microtubules provide the framework for chromosomal reorganisation and cell division. The aim of this study was to use fluorescence and confocal laser scanning microscopy to examine changes in the distribution of these important cytoskeletal elements and their relationship to chromatin configuration during the maturation of horse oocytes in vitro. Oocytes were cultured in M199 supplemented with pFSH and eLH and, at 0, 12, 24, and 36 hr after the onset of culture, they were fixed for immunocytochemistry and stained with markers for microtubules (a monoclonal anti-alpha-tubulin antibody), microfilaments (AlexaFluor 488 Phalloidin) and DNA (TO-PRO(3)). At the germinal vesicle stage, oocyte chromatin was amorphous and poorly condensed and the microfilaments and microtubules were distributed relatively evenly throughout the ooplasm. After germinal vesicle breakdown, the microtubules were aggregated around the now condensed chromosomes and the microfilaments had become concentrated within the oocyte cortex. During metaphase I, microtubules were detected only in the meiotic spindle, as elongated asters encompassing the aligned chromosomes, and, as maturation progressed through anaphase-I and telophase-I, the spindle assumed a more eccentric position and gradually rotated to assist in the separation of the homologous chromosomes and in the subsequent formation of the first polar body. During metaphase II, the meiotic spindle was a symmetrical, barrel-shaped structure with two poles and with the chromosomes aligned along its midline. At this stage, microtubules were found intermingled with chromatin within the polar body and, although, the bulk of the microfilaments remained within the oocyte cortex, a rich domain was found overlying the spindle. Thus, during the in vitro maturation of horse oocytes both the microfilament and microtubular elements of the cytoskeleton were seen to reorganise dramatically in a fashion that appeared to enable chromosomal alignment and segregation.

Progesterone in mare follicular fluid induces the acrosome reaction in stallion spermatozoa and enhances in vitro binding to the zona pellucida

The aim of this study was to investigate whether mare follicular fluid (FF) induces the acrosome reaction (AR) in stallion spermatozoa and, if so, to identify the component in FF responsible for it. Furthermore, the effect of this component on sperm-zona binding and the subsequent AR was studied. Pooled FF, aspirated from the preovulatory follicles of mares in oestrous, was used and aliquots of the fluid were treated with charcoal to remove steroids (CFF). Charcoal treatment reduced the progesterone concentration in FF from 153 to < 2 ng/mL. Spermatozoa from fertile stallions collected by a swim-up procedure were preincubated in modified Tyrode's medium for 5 h and then incubated for 30 min at 37 degrees C with either (1) 50% FF + 50% CFF, (2) 50% FF + 50% CFF + 150 ng/mL progesterone, (3) 50% CFF + 150 ng/mL progesterone, (4)150 ng/mL progesterone or (5) modified Tyrode's medium alone. The sperm-hemizona assay was applied: (a) to compare the number of spermatozoa bound to a hemizona in the presence and absence of 1.5, 15 or 150 ng/mL progesterone after 1 h co-incubation of spermatozoa and hemizonae, (b) to compare the incidence of the AR in sperm-hemizona complexes incubated for 1 h in the presence and absence of 1 microgram/mL progesterone. Both spermatozoa in suspension and bound to a hemizona were treated with the supravital dye Ethidium homodimer and fixed. Their plasma membranes were permeabilized, and the outer acrosomal membranes were labelled with FITC-PNA. Viable spermatozoa without the outer acrosomal membrane were considered as physiologically acrosome-reacted. Results showed that (1) FF induced a higher percentage of AR than did CFF or modified Tyrode's medium, (2) addition of 150 ng/mL progesterone to CFF restored 77% of the AR-inducing activity and (3) CFF and modified Tyrode's medium both induced the AR to a similar extent when supplemented with 150 ng/mL progesterone. Neither FF nor progesterone treatment affected sperm viability severely. The number of spermatozoa bound to a hemizona in the presence of 15 and 150 ng/mL progesterone was significantly higher (p < 0.05) than the number of spermatozoa bound in the absence of progesterone. A higher incidence of the AR was found in sperm-hemizona complexes incubated in the presence of progesterone (55.6 +/- 3.4% vs. 27.1 +/- 4.3%, in the presence and absence of progesterone, respectively) (n = 15, p < 0.05). It is concluded that mare FF can induce the AR in stallion spermatozoa. Progesterone is the physiological component responsible for this AR-inducing capacity. Progesterone enhances sperm-zona binding activity and exerts an additive effect on the zona-induced AR.