Effect of Continuous Trio Breeding Compared with Continuous Pair Breeding in 'Shoebox' Caging on Measures of Reproductive Performance in Estrogen Receptor Knockout Mice

Some performance standards for continuous trio breeding in 'shoebox' cages for inbred stocks and outbred strains of mice challenge the minimum floor space recommendations in the 8th edition of the Guide for the Care and Use of Laboratory Animals. In our study, we evaluated whether continuous trio breeding could be successfully applied to a breeding colony of genetically engineered mice housed in shoebox cages with a floor area of 67.6 in2. Mice heterozygous for genetically engineered mutations to estrogen receptors and their wildtype counterparts were continuously bred as trios or pairs. Confounding environmental factors were controlled through standardized husbandry practices and husbandry, and all mice were bred simultaneously to control for temporal factors. Several measures of reproductive performance-including number of litters per female, production index, interlitter interval, litter size at birth, litter size at weaning, weaning rate, and body weight of pups at weaning- were evaluated over approximately 6 mo. Regardless of genotype, interlitter interval, litter size at birth, and litter size at weaning were significantly lower for trio-bred mice than for pair-bred mice. In addition, significant interactions emerged between genotype and breeding strategy for these reproductive measures. Furthermore, significant differences between genotypes occurred for interlitter interval and weaning rate, regardless of breeding strategy. Underlying mechanisms to account for effects of genotype on interlitter interval and the interaction of genotype with breeding strategy were unclear but may reflect effects of overcrowding and reproductive suppression.

Accelerating Biomedical Discoveries through Rigor and Transparency

Difficulties in reproducing published research findings have garnered a lot of press in recent years. As a funder of biomedical research, the National Institutes of Health (NIH) has taken measures to address underlying causes of low reproducibility. Extensive deliberations resulted in a policy, released in 2015, to enhance reproducibility through rigor and transparency. We briefly explain what led to the policy, describe its elements, provide examples and resources for the biomedical research community, and discuss the potential impact of the policy on translatability with a focus on research using animal models. Importantly, while increased attention to rigor and transparency may lead to an increase in the number of laboratory animals used in the near term, it will lead to more efficient and productive use of such resources in the long run. The translational value of animal studies will be improved through more rigorous assessment of experimental variables and data, leading to better assessments of the translational potential of animal models, for the benefit of the research community and society.

Chromoplectic TPM3-ALK rearrangement in a patient with inflammatory myofibroblastic tumor who responded to ceritinib after progression on crizotinib

Ceritinib resulted in a significant, durable response of a metastatic inflammatory myofibroblastic tumor (IMT) after failure of crizotinib. A chromoplectic TPM3–ALK rearrangement involving many known oncogenes was found in the residual IMT. Ceritinib may be useful for patients with IMT after failure of crizotinib, and chromoplexy may have a role in the oncogenesis or treatment resistance of IMTs.

Background

Inflammatory myofibroblastic tumors (IMTs) are rare sarcomas that can occur at any age. Surgical resection is the primary treatment for patients with localized disease; however, these tumors frequently recur. Less commonly, patients with IMTs develop or present with metastatic disease. There is no standard of care for these patients and traditional cytotoxic therapy is largely ineffective. Most IMTs are associated with oncogenic ALK, ROS1 or PDGFRβ fusions and may benefit from targeted therapy.

Patient and methods

We sought to understand the genomic abnormalities of a patient who presented for management of metastatic IMT after progression of disease on crizotinib and a significant and durable partial response to the more potent ALK inhibitor ceritinib.

Results

The residual IMT was resected based on the recommendations of a multidisciplinary tumor sarcoma tumor board and analyzed by whole-genome mate pair sequencing. Analysis of the residual, resected tumor identified a chromoplectic TPM3–ALK rearrangement that involved many other known oncogenes and was confirmed by rtPCR.

Conclusions

In our analysis of the treatment-resistant, residual IMT, we identified a complex pattern of genetic rearrangements consistent with chromoplexy. Although it is difficult to know for certain if these chromoplectic rearrangements preceded treatment, their presence suggests that chromoplexy has a role in the oncogenesis of IMTs. Furthermore, this patient's remarkable response suggests that ceritinib should be considered as an option after progression on crizotinib for patients with metastatic or unresectable IMT and ALK mutations.

Chronic methamphetamine exposure prior to middle cerebral artery occlusion increases infarct volume and worsens cognitive injury in Male mice

Emerging evidence indicates that methamphetamine (MA) abuse can impact cardiovascular disease. In humans, MA abuse is associated with an increased risk of stroke as well as an earlier age at which the stroke occurs. However, little is known about how chronic daily MA exposure can impact ischemic outcome in either humans or animal models. In the present study, mice were injected with MA (10 mg/kg, i.p.) or saline once daily for 10 consecutive days. Twenty-four hours after the final injection, mice were subjected to transient middle cerebral artery occlusion (tMCAO) for one hour followed by reperfusion. Mice were tested for novel object memory at 96 h post-reperfusion, just prior to removal of brains for quantification of infarct volume using 2,3,5-Triphenyltetrazolium Chloride (TTC) staining. Mice treated with MA prior to tMCAO showed decreased object memory recognition and increased infarct volume compared to saline-treated mice. These findings indicate that chronic MA exposure can worsen both cognitive and morphological outcomes following cerebral ischemia.

Adoptive transfer of immune subsets prior to MCAO does not exacerbate stroke outcome in splenectomized mice

The peripheral immune response contributes to neurologic impairment after stroke and the extent of initial damage is greater in males than females. We have previously shown that spleen cells directly contribute to ischemic damage in males, as splenectomy prior to experimental stroke eliminates the sex differences in infarct volume. This study aims to determine which specific subset of immune cells exert pathogenic effects when injected 24 hours before MCAO induction into splenectomized male and female WT mice. The results demonstrate that CD4/CD8/CD11b treated mice had no significant effect on infarct volumes vs. vehicle-treated control mice after MCAO. However, there were significant alterations to the resident peripheral immune composition. These results suggest that there are regulatory factors resulting from splenectomy or other possible influences that inhibit peripheral immune cell contribution to neuroinflammation and thus contributing to differential effects of the spleen on stroke outcome in males and female mice.

A novel mouse model of thromboembolic stroke

BACKGROUND

We previously demonstrated that tissue plasminogen activator (tPA) reduces infarct size after mechanical middle cerebral artery occlusion (MCAO) in wild-type (WT) mice and transgenic mice expressing human leukocyte antigen DR2 (DR2-Tg). Clinically, tPA limits ischemic damage by dissolving the clot blocking blood flow through a cerebral artery. To mimic the clinical situation, we developed a new mouse model of thromboembolic stroke, and tested the efficacy of tPA in WT and DR2-Tg mice. New Method Autologous blood is withdrawn into a PE-8 catheter filled with 2 IU α-thrombin. After exposing the catheter briefly to air, the catheter is reintroduced into the external (ECA) and advanced into the internal carotid artery (ICA) to allow for intravascular injection of thrombin at the MCA bifurcation. To validate the model, we tested the effect of tPA on laser-Doppler perfusion (LDP) over the MCA territory and infarct size in WT and DR2-Tg mice.

RESULTS

The procedure results in a consistent drop in LDP, and leads to a highly reproducible ischemic lesion. When administered at 15min after thrombosis, tPA restored LDP and resulted in a significant reduction in infarct size at 24h after thrombosis in both WT and DR2-Tg.

COMPARISON WITH EXISTING METHODS

Our model significantly reduces surgery time, requires a single anesthesia exposure, and produces a consistent and predictable infarction, with low variability and mortality.

CONCLUSION

We validated the efficacy of tPA in restoring blood flow and reducing infarct in a new model of endovascular thromboembolic stroke in the mouse.

Regulatory CD8(+)CD122 (+) T-cells predominate in CNS after treatment of experimental stroke in male mice with IL-10-secreting B-cells

Clinical stroke induces inflammatory processes leading to cerebral and splenic injury and profound peripheral immunosuppression. IL-10 expression is elevated during major CNS diseases and limits inflammation in the brain. Recent evidence demonstrated that transfer of IL-10(+) B-cells reduced infarct volume in male C57BL/6J (wild-type, WT) recipient mice when given 24 h prior to or 4 h after middle cerebral artery occlusion (MCAO). The purpose of this study was to determine if passively transferred IL-10(+) B-cells can exert therapeutic and immunoregulatory effects when injected 24 h after MCAO induction in B-cell-sufficient male WT mice. The results demonstrated that IL-10(+) B-cell treated mice had significantly reduced infarct volumes in the ipsilateral cortex and hemisphere and improved neurological deficits vs. Vehicle-treated control mice after 60 min occlusion and 96 h of reperfusion. The MCAO-protected B-cell recipient mice had less splenic atrophy and reduced numbers of activated, inflammatory T-cells, decreased infiltration of T-cells and a less inflammatory milieu in the ischemic hemispheres compared with Vehicle-treated control mice. These immunoregulatory changes occurred in concert with the predominant appearance of IL-10-secreting CD8(+)CD122(+) Treg cells in both the spleen and the MCAO-affected brain hemisphere. This study for the first time demonstrates a major neuroprotective role for IL-10(+) B-cells in treating MCAO in male WT mice at a time point well beyond the ~4 h tPA treatment window, leading to the generation of a dominant IL-10(+)CD8(+)CD122(+) Treg population associated with spleen preservation and reduced CNS inflammation.

Targeting immune co-stimulatory effects of PD-L1 and PD-L2 might represent an effective therapeutic strategy in stroke

Stroke outcome is worsened by the infiltration of inflammatory immune cells into ischemic brains. Our recent study demonstrated that PD-L1- and to a lesser extent PD-L2-deficient mice had smaller brain infarcts and fewer brain-infiltrating cells vs. wild-type (WT) mice, suggesting a pathogenic role for PD-ligands in experimental stroke. We sought to ascertain PD-L1 and PD-L2-expressing cell types that affect T-cell activation, post-stroke in the context of other known co-stimulatory molecules. Thus, cells from male WT and PD-L-deficient mice undergoing 60 min of middle cerebral artery occlusion (MCAO) followed by 96 h of reperfusion were treated with neutralizing antibodies to study co-stimulatory and co-inhibitory interactions between CD80, cytotoxic T-lymphocyte antigen-4 (CTLA-4), PD-1, and PD-Ls that regulate CD8⁺ and CD4⁺ T-cell activation. We found that antibody neutralization of PD-1 and CTLA-4 signaling post-MCAO resulted in higher proliferation in WT CD8⁺ and CD4⁺ T-cells, confirming an inhibitory role of PD-1 and CTLA-4 on T-cell activation. Also, CD80/CD28 interactions played a prominent regulatory role for the CD8⁺ T-cells and the PD-1/PD-L2 interactions were dominant in controlling the CD4⁺ T-cell responses in WT mice after stroke. A suppressive phenotype in PD-L1-deficient mice was attributed to CD80/CTLA-4 and PD-1/PD-L2 interactions. PD-L2 was crucial in modulating CD4⁺ T-cell responses, whereas PD-L1 regulated both CD8⁺ and CD4⁺ T-cells. To establish the contribution of PD-L1 and PD-L2 on regulatory B-cells (Bregs), infarct volumes were evaluated in male PD-L1- and PD-L2-deficient mice receiving IL-10⁺ B-cells 4h post-MCAO. PD-L2- but not PD-L1-deficient recipients of IL-10⁺ B-cells had markedly reduced infarct volumes, indicating a regulatory role of PD-L2 on Bregs. These results imply that PD-L1 and PD-L2 differentially control induction of T- and Breg-cell responses after MCAO, thus suggesting that selective targeting of PD-L1 and PD-L2 might represent a valuable therapeutic strategy in stroke.

Sex differences in microRNA expression during development in rat cortex

There are important sex differences in the risk and outcome of conditions and diseases between males and females. For example, stroke occurs with greater frequency in men than in women across diverse ethnic backgrounds and nationalities. Work from our lab and others have revealed a sex-specific sensitivity to cerebral ischemia whereby males exhibit a larger extent of brain damage following an ischemic event compared to females. Studies suggest that the difference in male and female susceptibility to ischemia may be triggered by innate variations in gene regulation and protein expression between the sexes that are independent of post-natal exposure to sex hormones. We have shown that there are differences in microRNA (miRNA) expression in adult male and female brain following focal cerebral ischemia in mouse cortex. Herein we examine a role for differential expression of miRNAs during development in male and female rat cortex as potential effectors of the phenotype that leads to sex differences to ischemia. Expression studies in male and female cortices isolated from postnatal day 0 (P0), postnatal day 7 (P7), and adult rats using TaqMan Low Density miRNA arrays and NanoString nCounter analysis revealed differential miRNA levels between males and females at each developmental stage. We focused on the miR-200 family of miRNAs that showed higher levels in females at P0, but higher levels in males at P7 that persisted into adulthood, and validated the expression of miR-200a, miR-200b, and miR-429 by individual qRT-PCR as these are clustered on chromosome 5 and may be transcriptionally co-regulated. Prediction analysis of the miR-200 miRNAs revealed that genes within the Gonadotropin releasing hormone receptor pathway are the most heavily targeted. These studies support that developmental changes in miRNA expression may influence phenotypes in adult brain that underlie sexually dimorphic responses to disease, including ischemia.

Treatment of experimental stroke with IL-10-producing B-cells reduces infarct size and peripheral and CNS inflammation in wild-type B-cell-sufficient mice

Clinical stroke induces inflammatory processes leading to cerebral and splenic injury and profound peripheral immunosuppression. IL-10 expression is elevated during major CNS diseases and limits inflammation in the brain. Recent evidence demonstrated that absence of B-cells led to larger infarct volumes and CNS damage after middle cerebral artery occlusion (MCAO) that could be prevented by transfer of IL-10(+) B-cells. The purpose of this study was to determine if the beneficial immunoregulatory effects on MCAO of the IL-10(+) B-cell subpopulation also extends to B-cell-sufficient mice that would better represent stroke subjects. CNS inflammation and infarct volumes were evaluated in male C57BL/6J (WT) mice that received either RPMI or IL-10(+) B-cells and underwent 60 min of middle cerebral artery occlusion (MCAO) followed by 96 h of reperfusion. Transfer of IL-10(+) B-cells markedly reduced infarct volume in WT recipient mice when given 24 h prior to or 4 h after MCAO. B-cell protected (24 h pre-MCAO) mice had increased regulatory subpopulations in the periphery, reduced numbers of activated, inflammatory T-cells, decreased infiltration of T-cells and a less inflammatory milieu in the ischemic hemispheres of the IL-10(+) B-cell-treated group. Moreover, transfer of IL-10(+) B-cells 24 h before MCAO led to a significant preservation of regulatory immune subsets in the IL-10(+) B-cell protected group presumably indicating their role in immunomodulatory mechanisms, post-stroke. Our studies are the first to demonstrate a major immunoregulatory role for IL-10(+) regulatory B-cells in preventing and treating MCAO in WT mice and also implicating their potential role in attenuating complications due to post-stroke immunosuppression.

MicroRNA responses to focal cerebral ischemia in male and female mouse brain

Stroke occurs with greater frequency in men than in women across diverse ethnic backgrounds and nationalities. Work from our lab and others have revealed a sex-specific sensitivity to cerebral ischemia whereby males exhibit a larger extent of brain damage resulting from an ischemic event compared to females. Previous studies revealed that microRNA (miRNA) expression is regulated by cerebral ischemia in males; however, no studies to date have examined the effect of ischemia on miRNA responses in females. Thus, we examined miRNA responses in male and female brain in response to cerebral ischemia using miRNA arrays. These studies revealed that in male and female brains, ischemia leads to both a universal miRNA response as well as a sexually distinct response to challenge. Target prediction analysis of the miRNAs increased in male or female ischemic brain reveal sex-specific differences in gene targets and protein pathways. These data support that the mechanisms underlying sexually dimorphic responses to cerebral ischemia includes distinct changes in miRNAs in male and female brain, in addition to a miRNA signature response to ischemia that is common to both.

Abstract W P92: Preclinical Evaluation of Recombinant T-cell Receptor Ligand RTL1000 as a Therapeutic Agent in Stroke

Objective: RTL1000, a partial human MHC molecule coupled to a human myelin peptide, reduces infarct size after experimental stroke in HLA-DR2 transgenic mice expressing the human MHC class II allele. In this study, we characterized the therapeutic window of RTL1000. We then determined if RTL1000 efficacy is altered when combined with t-PA, a standard therapy for stroke, and if it affords long-term neurobehavioral functional improvement after stroke in mice.

Methods: Male DR2 mice underwent 60 min of intraluminal MCA occlusion (MCAO). RTL1000 (100 μg) or vehicle (100 μl) was given S.C. at 4, 6 or 8 h after MCAO, followed by 3 daily S.C. injections. t-PA (10 mg/kg) or vehicle was infused I.V. over 30 min starting at 15 min into ischemia. Brains were collected at either 24 or 96 h of reperfusion. Cortical, striatal and hemispheric infarcts were measured after staining with 2, 3, 5-triphenyltetrazolium chloride. Behavioral testing neuroscore, open field, paw preference and novel object recognition was performed up to 28 days after MCAO.

Results: RTL1000 significantly reduced infarct size when administered at 4 and 6, but not 8 h after MCAO. Protection was more robust when RTL1000 was given at 4 h, and was limited to cortex when first administration was delayed for 6 h. When administered alone, t-PA reduced infarct size when measured at 24 but not 96 h after MCAO. Importantly, RTL1000 alone reduced infarct size at 96 h after MCAO, and the addition of t-PA did not reduce its ability to protect against ischemic injury. Behavioral testing showed RTL1000 had no effect on acute cognitive impairment on day 7, but improved long term cognitive outcome 28 days after MCAO.

Conclusions: RTL1000 is protective against ischemic stroke with a therapeutic window of up to 6 h. Protection by RTL1000 is preserved in the presence of t-PA, is long-lasting and improves neurobehavioral functional outcomes after experimental cerebral ischemia.

Abstract T P221: Effect of CD4 And CD8 T Lymphocytes on Infarct Volume Following Experimental Stroke in Male Splenectomized Mice

We have previously shown profound splenic activation by 6 hours following experimental stroke, resulting in rapid and widespread increased production of inflammatory factors by basal and activated splenocytes in male mice. Our lab and others have also shown a subsequent extensive loss of lymphocytes and increased lymphocyte apoptosis in spleen 12 hours after experimental stroke. Lastly, we and others have shown that splenic immunocytes can contribute to increased brain inflammation and infarct volume. However, it is unclear which splenic immunocyte populations may contribute to the evolving ischemic brain injury. Using a mouse splenectomy model and adoptive cell transfer protocols, we evaluated the effect of different splenic immunocyte populations, specifically CD4 and CD8 T lymphocytes, on infarct volume. Male C57BL/6J mice were splenectomized 14 days before experimental stroke and treated 24 hours before experimental stroke with either vehicle (saline), CD4 T lymphocytes, or CD8 T lymphocytes obtained from GFP reporter mice. Each mouse (n=8-10 per group) then underwent 60 minutes of middle cerebral artery occlusion via intraluminal filament. All mice were euthanized and brains collected at 96 hours of reperfusion. Infarct volume (% corrected contralateral structure) was determined by image analysis of coronal brain slices stained with 2,3,5-triphenyltetrazolium chloride. Adoptive transfer of GFP positive CD4 (cortex, 44±3%; striatum, 50±2%) or CD8 (cortex, 48±2%; striatum, 53±3%) T lymphocytes in splenectomized male mice did not alter infarct volume compared to vehicle-treated (cortex, 38±4%; striatum, 42±5%) splenectomized males (cortex, p=0.140; striatum, p=0.143). Although adding back CD4 or CD8 T lymphocytes did not appear to alter infarct volume, these immunocyte populations are comprised of both inflammatory and regulatory subtypes. Thus, future studies will evaluate the effect of different CD4 and CD8 subpopulations on ischemic brain outcomes. This study was supported by National Institutes of Health grant NS076013.

Abstract T P210: Splenectomy Attenuates Sex Differences in Infarct Volume Following Experimental Stroke in Mice

It is now increasingly clear that human stroke can have other serious consequences besides brain damage that can impact on patient survival and recovery. For example, many stroke patients succumb to CNS injury-induced immunodepression and fatal infections. Our prior work suggests that evolving cerebral ischemic injury elicits a cycle of injury from brain-to-spleen-to-brain that is strongly influenced by sex. We determined if splenic immunocytes are important in contributing to sex differences in post-ischemic brain injury. Male and female C57BL/6J mice were splenectomized 14 days before experimental stroke. Male and female mice with or without splenectomy (n=9-10 per group) then underwent 60 min of middle cerebral artery occlusion (MCAO) via intraluminal filament. Laser-Doppler flowmetry (LDF) was used to monitor cortical perfusion. All mice were euthanized and brains collected at 96 hours of reperfusion. Infarct volume (% corrected contralateral structure) was determined by image analysis of coronal brain slices stained with 2,3,5-triphenyltetrazolium chloride. Mean arterial blood pressure (MABP), blood gases (pH, P a O 2 , P a CO 2 ), and blood glucose were measured at 30 min MCAO and at 15 min of reperfusion in separate groups of male and female mice with or without splenectomy (n=5 per group). Relative LDF changes (% baseline), MABP, blood gases, and blood glucose during and after MCAO were comparable among the experimental groups. We observed that infarct volume in females (cortex, 41±4%; striatum, 55±6%) was smaller ( P <0.05) compared to males (cortex, 52±3%; striatum, 75±3%) at 96 hours of reperfusion. However, no differences (cortex, P =0.313; striatum, P =0.601) in infarct volume were seen between splenectomized male (cortex, 43±4%; striatum, 51±7%) and female (cortex, 38±4%; striatum, 46±5%) mice. Our data suggest that removal of all splenocyte lineages via splenectomy attenuates sex differences in post-ischemic brain injury. Future studies will evaluate the role of different splenic immunocyte subsets, such as T or B lymphocytes, on male vs. female ischemic brain outcomes. This study was supported by National Institutes of Health grant NS076013.

ASCL1 and RET expression defines a clinically relevant subgroup of lung adenocarcinoma characterized by neuroendocrine differentiation

ASCL1 is an important regulatory transcription factor in pulmonary neuroendocrine (NE) cell development, but its value as a biomarker of NE differentiation in lung adenocarcinoma (AD) and as a potential prognostic biomarker remains unclear. We examined ASCL1 expression in lung cancer samples of varied histologic subtype, clinical outcome and smoking status and compared with expression of traditional NE markers. ASCL1 mRNA expression was found almost exclusively in smokers with AD, in contrast to non-smokers and other lung cancer subtypes. ASCL1 protein expression by immunohistochemical (IHC) analysis correlated best with synaptophysin compared with chromogranin and CD56/NCAM. Analysis of a compendium of 367 microarray-based gene expression profiles in stage I lung adenocarcinomas identified significantly higher expression levels of the RET oncogene in ASCL1-positive tumors (ASCL1(+)) compared with ASCL1(-) tumors (q-value <10(-9)). High levels of RET expression in ASCL1(+) but not in ASCL1(-) tumors was associated with significantly shorter overall survival (OS) in stage 1 (P=0.007) and in all AD (P=0.037). RET protein expression by IHC had an association with OS in the context of ASCL1 expression. In silico gene set analysis and in vitro experiments by ASCL1 shRNA in AD cells with high endogenous expression of ASCL1 and RET implicated ASCL1 as a potential upstream regulator of the RET oncogene. Also, silencing ASCL1 in AD cells markedly reduced cell growth and motility. These results suggest that ASCL1 and RET expression defines a clinically relevant subgroup of ∼10% of AD characterized by NE differentiation.

PD-L1 enhances CNS inflammation and infarct volume following experimental stroke in mice in opposition to PD-1

Background

Stroke severity is worsened by recruitment of inflammatory immune cells into the brain. This process depends in part on T cell activation, in which the B7 family of co-stimulatory molecules plays a pivotal role. Previous studies demonstrated more severe infarcts in mice lacking programmed death-1 (PD-1), a member of the B7 family, thus implicating PD-1 as a key factor in limiting stroke severity. The purpose of this study was to determine if this protective effect of PD-1 involves either of its ligands, PD-L1 or PD-L2.

Methods

Central nervous system (CNS) inflammation and infarct volume were evaluated in male PD-L1 and PD-L2 knockout (^-/-) mice undergoing 60 minutes of middle cerebral artery occlusion (MCAO) followed by 96 hours of reperfusion and compared to wild-type (WT) C57BL/6J mice.

Results

PD-L1^-/- and PD-L2^-/- mice had smaller total infarct volumes compared to WT mice. The PD-L1^-/- and to a lesser extent PD-L2^-/- mice had reduced levels of proinflammatory activated microglia and/or infiltrating monocytes and CD4⁺ T cells in the ischemic hemispheres. There was a reduction in ischemia-related splenic atrophy accompanied by lower activation status of splenic T cells and monocytes in the absence of PD-L1, suggesting a pathogenic rather than a regulatory role for both PD-1 ligands (PD-Ls). Suppressor T cells (IL-10-producing CD8⁺CD122⁺ T cells) trafficked to the brain in PD-L1^-/- mice and there was decreased expression of CD80 on splenic antigen-presenting cells (APCs) as compared to the WT and PD-L2^-/- mice.

Conclusions

Our novel observations are the first to implicate PD-L1 involvement in worsening outcome of experimental stroke. The presence of suppressor T cells in the right MCAO-inflicted hemisphere in mice lacking PD-L1 implicates these cells as possible key contributors for controlling adverse effects of ischemia. Increased expression of CD80 on APCs in WT and PD-L2^-/- mice suggests an overriding interaction leading to T cell activation. Conversely, low CD80 expression by APCs, along with increased PD-1 and PD-L2 expression in PD-L1^-/- mice suggests alternative T cell signaling pathways, leading to a suppressor phenotype. These results suggest that agents (for example antibodies) that can target and neutralize PD-L1/2 may have therapeutic potential for treatment of human stroke.

IL-10-producing B-cells limit CNS inflammation and infarct volume in experimental stroke

Clinical stroke induces inflammatory processes leading to cerebral injury. IL-10 expression is elevated during major CNS diseases and limits inflammation in the brain. Recent evidence demonstrated that absence of B-cells led to larger infarct volumes and increased numbers of activated T-cells, monocytes and microglial cells in the brain, thus implicating a regulatory role of B-cell subpopulations in limiting CNS damage from stroke. The aim of this study was to determine whether the IL-10-producing regulatory B-cell subset can limit CNS inflammation and reduce infarct volume following ischemic stroke in B-cell deficient (μMT(-/-)) mice. Five million IL-10-producing B-cells were obtained from IL-10-GFP reporter mice and transferred i.v. to μMT(-/-)mice. After 24 h following this transfer, recipients were subjected to 60 min of middle cerebral artery occlusion (MCAO) followed by 48 h of reperfusion. Compared to vehicle-treated controls, the IL-10(+) B-cell-replenished μMT(-/-)mice had reduced infarct volume and fewer infiltrating activated T-cells and monocytes in the affected brain hemisphere. These effects in CNS were accompanied by significant increases in regulatory T-cells and expression of the co-inhibitory receptor, PD-1, with a significant reduction in the proinflammatory milieu in the periphery. These novel observations provide the first proof of both immunoregulatory and protective functions of IL-10-secreting B-cells in MCAO that potentially could impart significant benefit for stroke patients in the clinic.

Risk factor analysis may provide clues to diarrhea prevention in outdoor-housed rhesus macaques (Macaca mulatta)

Seventy-five percent of rhesus macaques at national primate research centers are housed outside. Annually, 15-39% of these animals experience diarrhea and require veterinary treatment for dehydration, electrolyte imbalance, or weight loss. An estimated 21-33% of these patients will die or be euthanized. Many studies have explored the various infectious etiologies of non-human primate diarrhea. However, there is little published information on diarrhea incidence rates and risk factors in outdoor-housed rhesus macaques. Without this information, it is challenging to determine endemic and epidemic diarrhea levels, or to develop and evaluate mitigation strategies. Using electronic medical records, we conducted a retrospective cohort study to calculate diarrhea incidence rates for rhesus macaques (N = 3,181) housed in three different outdoor housing types (corrals, shelters, and temporary housing) at the Oregon National Primate Research Center between November 1, 2009 and October 31, 2010. With multiple logistic regression analysis, we determined the relative risk of housing type, sex, and age on development of diarrhea. Diarrhea incidence and mortality in our population was lower than many published ranges. Type of outdoor housing, age, and previous diarrhea episode were positively correlated with diarrhea risk. Younger animals in smaller shelters and temporary housing had a greater risk of acquiring diarrhea, with juvenile animals (0.7-3.9 years) having the highest mortality rate. Sex was not a risk factor, but adult females with diarrhea were more likely to develop life-threatening complications than adult males. We also constructed a predictive model for diarrhea-associated mortality using Classification and Regression Tree. Findings from this study will be used to develop and evaluate mitigation strategies in our outdoor-housed population and to provide a foundation for genetic susceptibility and immune function testing.

Abstract WMP68: Loss Of Programmed Cell Death Ligand 1 And 2 Reduces Total Infarct Volume In Male Mice Following Experimental Stroke

The programmed cell death 1 receptor (PD-1) is an immunoglobulin superfamily member whose expression is induced in activated T cells, B cells, natural killer cells and monocytes. Binding of PD-1 to either of its two known ligands, programmed cell death ligand 1 and 2 (PD-L1 and PD-L2), induces inhibitory signals that regulate peripheral T cell tolerance and immune homeostasis. We have shown increased PD-1 expression in brain macrophages and glia as well as increased PD-L1 and PD-L2 expression in peripheral and brain B cells in mice after experimental stroke. Furthermore, we have observed increased infarct volume in PD-1 deficient mice, thus potentially implicating the PD-1/PD-L co-inhibitory pathway in post-stroke CNS inflammation. Using PD-L1 and PD-L2 deficient mice, we determined if PD-L1 or PD-L2 was also important in modulating stroke infarct volume. Young adult male wild-type (WT; n=11) and PD-L1 (n=9) and PD-L2 (n=12) knockout (KO) mice underwent 60 min of middle cerebral artery occlusion via intraluminal filament. Laser-Doppler flowmetry was used to monitor cortical perfusion. All mice were euthanized and brains collected at 96 h of reperfusion. Total infarct volume (% corrected contralateral hemisphere) was determined by image analysis of coronal brain slices stained with 2,3,5-triphenyltetrazolium chloride (TTC). Relative laser Doppler flowmetry changes (% baseline) during and after middle cerebral artery occlusion were equivalent among groups. Compared to male WT mice (WT vs. KO), genetic deletion of either PD-L1 (51+3% vs. 20+5%; p<0.001) or PD-L2 (51+3% vs. 35+4%; p=0.007) reduced total infarct volume. We also observed that total infarct volume was smaller in PD-L1 vs. PD-L2 KO mice (20+5% vs. 35+4%; p=0.017). Our findings along with our previous work in PD-1 deficient mice suggest that ligands other than PD-L1 or PD-L2 might be involved with PD-1 signaling in ischemic brain and that PD-L1 and PD-L2 might have other functions independent of PD-1 binding affecting infarct volumes. Future studies will evaluate the roles of PD-1, PD-L1, and PD-L2 in regulatory immune cell subsets that affect ischemic brain outcomes. This study was supported by National Institutes of Health grant NS075887.

Intrastriatal B-cell administration limits infarct size after stroke in B-cell deficient mice

Recent evidence emphasizes B-cells as a major regulatory cell type that plays an important role in limiting the pathogenic effects of ischemic stroke. The aim of the current study was to extend this initial observation to specifically examine the infiltration of regulatory B-cells and to determine if the effect of B-cells to limit the inflammatory response to cerebral ischemia is mediated by their action centrally or peripherally. Our data demonstrate the increased presence of a regulatory B-cell subset in the affected hemisphere of wild-type mice after middle cerebral artery occlusion (MCAO). We further explored the use of a novel method of stereotaxic cell delivery to bypass the blood brain barrier (BBB) and introduce CD19(+) B-cells directly into the striatum as compared to peripheral administration of B-cells. Infarct volumes after 60 minutes of MCAO and 48 hours of reperfusion were determined in B-cell deficient μMT( -/- ) mice with and without replacement of either B-cells or medium. Infarct size was significantly decreased in cerebral cortex after intrastriatal transfer of 100,000 B-cells to μMT(-/-) mice vs. controls, with a comparable effect on infarct size as obtained by 50 million B-cells transferred intraperitoneally. These findings support the hypothesis that B-cells play a protective role against ischemic brain injury, and suggest that B-cells may serve as a novel therapeutic agent for modulating the immune response in central nervous system inflammation after stroke.

Isoflurane preconditioning protects neurons from male and female mice against oxygen and glucose deprivation and is modulated by estradiol only in neurons from female mice

The volatile anesthetic, isoflurane, can protect the brain if administered before an insult such as an ischemic stroke. However, this protective "preconditioning" response to isoflurane is specific to males, with females showing an increase in brain damage following isoflurane preconditioning and subsequent focal cerebral ischemia. Innate cell sex is emerging as an important player in neuronal cell death, but its role in the sexually dimorphic response to isoflurane preconditioning has not been investigated. We used an in vitro model of isoflurane preconditioning and ischemia (oxygen and glucose deprivation, OGD) to test the hypotheses that innate cell sex dictates the response to isoflurane preconditioning and that 17β-estradiol attenuates any protective effect from isoflurane preconditioning in neurons via nuclear estrogen receptors. Sex-segregated neuron cultures derived from postnatal day 0-1 mice were exposed to either 0% or 3% isoflurane preconditioning for 1 h. In separate experiments, 17β-estradiol and the non-selective estrogen receptor antagonist ICI 182,780 were added 24 h before preconditioning and then removed at the end of the preconditioning period. Twenty-three hours after preconditioning, all cultures underwent 2 h of OGD. Twenty-four hours following OGD, cell viability was quantified using calcein-AM fluorescence. We observed that isoflurane preconditioning increased cell survival following subsequent OGD regardless of innate cell sex, but that the presence of 17β-estradiol before and during isoflurane preconditioning attenuated this protection only in female neurons independent of nuclear estrogen receptors. We also found that independent of preconditioning treatment, female neurons were less sensitive to OGD compared with male neurons and that transient treatment with 17β-estradiol protected both male and female neurons from subsequent OGD. More studies are needed to determine how cell type, cell sex, and sex steroids like 17β-estradiol may impact on anesthetic preconditioning and subsequent ischemic outcomes in the brain.

Androgen receptor overexpression is neuroprotective in experimental stroke

Male sex is a known risk factor in human stroke. However, the role of the cognate receptor for androgens-the androgen receptor (AR)-in stroke outcome remains unclear. Here, we found that AR mRNA is downregulated in the peri-infarct tissue of gonadally intact male mice subjected to middle cerebral artery occlusion (MCAO) and 6 h reperfusion. We then used genetically engineered mice overexpressing AR in brain (AR-Tg) to compare outcomes from MCAO in intact or castrated males and to evaluate the neuroprotective role of dihydrotestosterone (DHT) replacement in AR-Tg castrates. A further evaluation of AR overexpression in ischemic paradigms was performed using rat PC12 cells transfected with human AR and treated with oxidative and apoptotic stressors. We then studied the role of DHT in cultures overexpressing AR. Our results show (1) ischemia alters the expression of AR by decreasing AR mRNA levels, (2) AR overexpression is protective in vivo against MCAO in intact and castrated AR-Tg mice and in vitro against oxidative and apoptotic stressors in AR-PC12 cells, and (3) DHT does not enhance the protection triggered by AR overexpression in AR-Tg castrated mice nor in AR-PC12 cells.

Involvement of Stat3 in mouse brain development and sexual dimorphism: a proteomics approach

Although the role of STAT3 in cell physiology and tissue development has been largely investigated, its involvement in the development and maintenance of nervous tissue and in the mechanisms of neuroprotection is not yet known. The potentially wide range of STAT3 activities raises the question of tissue- and gender-specificity as putative mechanisms of regulation. To explore the function of STAT3 in the brain and the hypothesis of a gender-linked modulation of STAT3, we analyzed a neuron-specific STAT3 knockout mouse model investigating the influence of STAT3 activity in brain protein expression pattern in both males and females in the absence of neurological insult. We performed a proteomic study aimed to reveal the molecular pathways directly or indirectly controlled by STAT3 underscoring its role in brain development and maintenance. We identified several proteins, belonging to different neuronal pathways such as energy metabolism or synaptic transmission, controlled by STAT3 that confirm its crucial role in brain development and maintenance. Moreover, we investigated the different processes that could contribute to the sexual dimorphic behavior observed in the incidence of neurological and mental disease. Interestingly both STAT3 KO and gender factors influence the expression of several mitochondrial proteins conferring to mitochondrial activity high importance in the regulation of brain physiology and conceivable relevance as therapeutic target.

Dietary soy may not confound acute experimental stroke infarct volume outcomes in ovariectomized female rats

Oestrogen administration can alter experimental stroke outcomes. Soy as a source of phytoestrogens may therefore modulate responses in 'oestrogen-sensitive' stroke models, thus potentially confounding results. We evaluated the effects of dietary soy on acute infarct volumes in a pilot study using a rat focal stroke model. We hypothesized that ovariectomized (OVX) rats fed a soy-rich diet would have smaller acute infarct volumes than rats fed a soy-free diet. OVX rats were randomly assigned to a soy-free (n = 6) or a soy-rich (n = 6) diet for four weeks and weighed weekly. Following the dietary trial, rats underwent 2 h of middle cerebral artery occlusion (MCAO). Mean arterial blood pressure, rectal and temporalis muscle temperatures, arterial blood gases and blood glucose were recorded peri-ischaemia. Rats were euthanized 22 h following 2 h of MCAO. Brains were stained with 2,3,5-triphenyl tetrazolium chloride for acute infarct volume analysis. Uterine weight and histology were also evaluated as additional internal oestrogen-sensitive controls. Rats on the soy-free diet had greater gains in body weight (259 +/- 6% baseline body weight) than rats on the soy-rich diet (238 +/- 4% baseline body weight). No differences were seen in uterine weight and histology, peri-ischaemic physiological parameters and infarct volumes between the treatment groups. The results of this pilot study suggest that the dietary soy level tested may not alter acute infarct volumes in ischaemic female rat brain. More studies addressing the potential confounding effects of dietary soy in 'oestrogen-sensitive' stroke models are needed if investigators are to make informed choices regarding diets used in experimental stroke research.

Isoflurane preconditioning neuroprotection in experimental focal stroke is androgen-dependent in male mice

Isoflurane preconditioning neuroprotection in experimental stroke is male-specific. The role of androgens in the ischemic sensitivity of isoflurane preconditioned male brain and whether androgen effects are androgen receptor dependent were assessed. Male C57BL/6 mice were implanted with flutamide (androgen receptor antagonist), or castrated and implanted with testosterone, dihydrotestosterone, flutamide, letrozole (aromatase inhibitor), or vehicle 7-13 days before preconditioning. P450 estrogen aromatase wild-type and knockout mice were also evaluated. All mice were preconditioned for 4 h with 0% (sham preconditioning) or 1% isoflurane (isoflurane preconditioning) and recovered for 24 h. Mice then underwent 2 h of middle cerebral artery occlusion and were evaluated 22 h later for infarct volume. For neurobehavioral outcomes, sham and isoflurane preconditioned castrated male+/-dihydrotestosterone groups underwent 1 h of middle cerebral artery occlusion followed by 9 days of reperfusion. Isoflurane preconditioning neuroprotection relative to infarct volume outcomes were testosterone and dihydrotestosterone dose-specific and androgen receptor-dependent. Relative to long-term neurobehavioral outcomes, front paw sensorimotor function improved in isoflurane preconditioned mice regardless of androgen status while androgen replacement independently improved sensorimotor function. In contrast, isoflurane preconditioning improved cognitive function in castrates lacking endogenous androgens, but this improvement was absent in androgen replaced mice. Our findings suggest that androgen availability during isoflurane preconditioning may influence infarct volume and neurobehavioral outcomes in male mice following experimental stroke.

Poly (ADP-ribose) polymerase-1 initiated neuronal cell death pathway--do androgens matter?

Activation of poly (ADP-ribose) polymerases (PARP) contributes to ischemic damage by causing neuronal nicotinamide adenine dinucleotide (NAD(+)) depletion, release of apoptosis-inducing factor and consequent caspase-independent cell death. PARP-mediated cell death is sexually dimorphic, participating in ischemic damage in the male brain, but not the female brain. We tested the hypothesis that androgen signaling is required for this male-specific neuronal cell death pathway. We observed smaller damage following focal cerebral ischemia (MCAO) in male PARP-1 knockout mice compared to wild type (WT) as well as decreased damage in male mice treated with the PARP inhibitor PJ34. Protection from ischemic damage provided by PJ-34 in WT mice is lost after removal of testicular androgens (CAST) and rescued by androgen replacement. CAST PARP-1 KO mice exhibit increased damage compared to intact male KO mice, an effect reversed by androgen replacement in an androgen receptor-dependent manner. Lastly, we observed that ischemia causes an increase in PARP-1 expression that is diminished in the absence of testicular androgens. Our data indicate that PARP-mediated neuronal cell death in the male brain requires intact androgen-androgen receptor signaling.

Refining timed pregnancies in two strains of genetically engineered mice

In order to efficiently generate genetically engineered mouse (GEM) fetuses or neonates of a specified age range, researchers must develop strain-specific strategies, including reliable early pregnancy detection. The authors evaluated pregnancy indices (pregnancy rate, plug rate, pregnant plugged rate, first litter size and body weight) in two GEM breeding colonies: homozygous soluble epoxide hydrolase knockout (sEHKO) mice (n=164 females) and L7-tau-green fluorescent protein (GFP) transgenic mice (n=61 females). The goals of the study were to determine the most accurate early pregnancy indicator and to reliably and cost-effectively produce timed pregnant females that were between gestation days 16 and 18. The authors set up each timed mating by placing two naturally synchronized females with a male for 48 h. When males were present, personnel checked each female daily for a vaginal plug. They then weighed the females immediately, 1 week and 2 weeks after removing the males. In both sEHKO and GFP colonies, increases in body weight at 1 and 2 weeks after timed male exposure more reliably and consistently indicated pregnancy than did plug detection. Further evaluations and protocol refinements are planned based on litter size and litter number in these colonies.

Withdrawal of corticosteroids in inflammatory bowel disease patients after dependency periods ranging from 2 to 45 years: a proposed method

BACKGROUND

Even in the biologic era, corticosteroid dependency in IBD patients is common and causes a lot of morbidity, but methods of withdrawal are not well described.

AIM

To assess the effectiveness of a corticosteroid withdrawal method.

METHODS

Twelve patients (10 men, 2 women; 6 ulcerative colitis, 6 Crohn's disease), median age 53.5 years (range 29-75) were included. IBD patients with quiescent disease refractory to conventional weaning were transitioned to oral dexamethasone, educated about symptoms of the corticosteroid withdrawal syndrome (CWS) and weaned under the supervision of an endocrinologist. When patients failed to wean despite a slow weaning pace and their IBD remaining quiescent, low dose synthetic ACTH stimulation testing was performed to assess for adrenal insufficiency. Multivariate analysis was performed to assess predictors of a slow wean.

RESULTS

Median durations for disease and corticosteroid dependency were 21 (range 3-45) and 14 (range 2-45) years respectively. Ten patients (83%) were successfully weaned after a median follow-up from final wean of 38 months (range 5-73). Disease flares occurred in two patients, CWS in five and ACTH testing was performed in 10. Multivariate analysis showed that longer duration of corticosteroid use appeared to be associated with a slower wean (P = 0.056).

CONCLUSIONS

Corticosteroid withdrawal using this protocol had a high success rate and durable effect and was effective in patients with long-standing (up to 45 years) dependency. As symptoms of CWS mimic symptoms of IBD disease flares, gastroenterologists may have difficulty distinguishing them, which may be a contributory factor to the frequency of corticosteroid dependency in IBD patients.

Oesophageal cancer: caregiver mental health and strain

OBJECTIVE

To investigate strain and mental health among family caregivers of oesophageal cancer patients and possible factors associated with caregiver mental health and strain.

METHODS

Patients with oesophageal adenocarcinoma in Ireland were recruited into the FINBAR study (the main aim of which was to investigate factors influencing the Barrett's adenocarcinoma relationship). Carers completed the 13-item Caregiver Strain Index and the General Health Questionnaire-30 (GHQ) in the context of a brief interview with trained research staff that was undertaken separately from the interview with each cancer patient.

RESULTS

Two hundred and twenty-seven patients participated in the FINBAR study. A total of 39 patients did not have a family carer or the carer could not be identified. Fifty percent (94/188) of carers completed the questionnaires. Mean (SD) scores for strain (6.65, SD=3.63) and mental health status (10.21, SD=7.30) were high and 71% of carers scored >5 on the GHQ indicating psychological distress. There was a statistically significant positive relationship between level of strain experienced by caregivers and the severity of their mental health status and whether or not carers scored >5 on the GHQ. Relatives were 1.70 (95% CI 1.34-2.15) times more likely to be defined as high scorers with each unit increase in the CSI score.

CONCLUSIONS

A significant proportion of caregivers experienced high levels of strain and psychological distress. There is a need to provide appropriate support and services targeted specifically at reducing the considerable strain of caring for patients with oesophageal cancer, particularly for carers of patients from lower socioeconomic groups.

Can gender differences be evaluated in a rhesus macaque (Macaca mulatta) model of focal cerebral ischemia?

Gender differences, sex steroid effects, and sex-specific candidate therapeutics in ischemic stroke have been studied in rodents but not in nonhuman primates. In this feasibility study (n = 3 per group), we developed a model of transient focal cerebral ischemia in adult male and female rhesus macaques that consistently includes white matter injury. The animals also were used to determine whether gender-linked differences in histopathologic outcomes could be evaluated in this model in future, larger preclinical trials. Histologic brain pathology was evaluated at 4 d after 90 min of reversible occlusion of the middle cerebral artery (MCA). MCA occlusion was accomplished by using a transorbital approach and temporary placement of an aneurysm clip. Male and female rhesus macaques 7 to 11 y of age were studied. Baseline and intraischemic blood glucose, systolic blood pressure, heart rate, oxygen saturation, end-tidal CO2, and rectal temperatures were not different among groups. The variability in injury volume was comparable to that observed in human focal cerebrovascular ischemia and in other nonhuman primate models using proximal MCA occlusion. In this small sample, the volume of injury was not different between male and female subjects, but observed variability was higher in female caudate nucleus, putamen, and hemisphere. This report is the first to compare cerebral ischemic outcomes in female and male rhesus macaques. The female rhesus macaque ischemic stroke model could be used after rodent studies to provide preclinical data for clinical trials in women.

Decreased damage from transient focal cerebral ischemia by transfusion of zero-link hemoglobin polymers in mouse

BACKGROUND AND PURPOSE

Transfusion of large polymers of hemoglobin avoids the peripheral extravasation and hypertension associated with crosslinked tetrameric hemoglobin transfusion and may be more effective in rescuing brain from focal ischemia. Effects of transfusion of high-oxygen-affinity hemoglobin polymers of different weight ranges were determined.

METHODS

Hypervolemic exchange transfusion was performed during 2 hours of middle cerebral artery occlusion in mice.

RESULTS

Compared to transfusion with a 5% albumin solution or no transfusion, infarct volume was reduced 40% by transfusion of a 6% solution containing hemoglobin polymers in the nominal range 500 to 14 000 kDa. Infarct volume was not significantly reduced by transfusion of a lower concentration of 2% to 3% of this size range of polymers, 6% hemoglobin solutions without removal of polymers <500 kDa or >14000 kDa, or crosslinked hemoglobin tetramers with normal oxygen affinity. Exchange transfusion with the 6% solution of the 500 to 14 000 kDa hemoglobin polymers did not improve the distribution of cerebral blood flow during focal ischemia and, in mice without ischemia, did not affect flow to brain or other major organs.

CONCLUSIONS

An intermediate size range of polymerized bovine hemoglobin possessing high oxygen affinity appears optimal for rescuing mouse brain from transient focal cerebral ischemia. A minimum concentration of a 6% solution is required, the rescue is superior to that obtained with crosslinked tetrameric hemoglobin possessing normal oxygen affinity, and tissue salvage is not associated with increased blood flow. This polymer solution avoids the adverse effects of severe renal and splanchnic vasoconstriction seen with crosslinked tetrameric hemoglobin.

Relationship between Helicobacter pylori infection and gastric atrophy and the stages of the oesophageal inflammation, metaplasia, adenocarcinoma sequence: results from the FINBAR case-control study

OBJECTIVE

A number of studies have shown an inverse association between infection with Helicobacter pylori and oesophageal adenocarcinoma (OAC). The mechanism of the apparent protection against OAC by H pylori infection and, in particular, the role of gastric atrophy is disputed. The relationship between all stages of the oesophageal inflammation, metaplasia, adenocarcinoma sequence and H pylori infection and gastric atrophy was explored.

METHODS

A case-control study involving 260 population controls, 227 OAC, 224 Barrett's oesophagus (BO) and 230 reflux oesophagitis (RO) patients recruited within Ireland was carried out. H pylori and CagA (cytotoxin-associated gene product A) infection was diagnosed serologically by western blot, and pepsinogen I and II levels were measured by enzyme immunoassay. Gastric atrophy was defined as a pepsinogen I/II ratio of <3.

RESULTS

H pylori seropositivity was inversely associated with OAC, BO and RO; adjusted ORs (95% CIs), 0.49 (0.31 to 0.76), 0.35 (0.22 to 0.56) and 0.42 (0.27 to 0.65), respectively. Gastric atrophy was uncommon (5.3% of all subjects), but was inversely associated with non-junctional OAC, BO and RO; adjusted ORs (95% CIs), 0.34 (0.10 to 1.24), 0.23 (0.05 to 0.96) and 0.27 (0.08 to 0.88), respectively. Inverse associations between H pylori and the disease states remained in gastric atrophy-negative patients.

CONCLUSION

H pylori infection and gastric atrophy are associated with a reduced risk of OAC, BO and RO. While use of the pepsinogen I/II ratio as a marker for gastric atrophy has limitations, these data suggest that although gastric atrophy is involved it may not fully explain the inverse associations observed with H pylori infection.

Mouth width prediction in craniofacial identification: cadaver tests of four recent methods, including two techniques for edentulous skulls

An understanding of the structural relationships between the soft tissue anatomy of the face and the hard tissue anatomy of the skull is significant for craniofacial identification methods employed in forensic anthropology and forensic dentistry. Typically, mouth characteristics have been predicted from the teeth but this proves problematic in edentulous skulls. Some clue may, however, be provided by non-dental features. This study investigates the usefulness of the infraorbital and the mental foramen position for determining mouth width and additionally reports on accuracy tests using two other recently proposed methods that depend on the teeth: i) Krogman and İşcan's radiating mouth width prediction guideline; and ii) Stephan and Henneberg's 75% rule. Dissections of nine human cadavers indicate that the most accurate mouth width prediction method is the 75% rule (mean error of -2.4 mm) followed by the distance between the infraorbital foramen (mean error of -3.3 mm). Krogman and İşcan's radiating method, as interpreted by Wilkinson, underestimated mouth width by 7.3mm on average, while the distance between the mental foramen underestimated mouth width by 12.9 mm. These results suggest that the infraorbital foramen can be used as a relatively good predictor of mouth width in edentulous skulls, however, the 75% rule should be given precedence if the dentition is present.

A novel method for assessing sex-specific and genotype-specific response to injury in astrocyte culture

Female astrocytes sustain less cell death from oxygen-glucose deprivation (OGD) than male astrocytes. Arimidex, an aromatase inhibitor, abolishes these sex differences. To verify sex-dependent differences in P450 aromatase function in astrocyte cell death following OGD, we developed a novel method that uses sex-specific and genotype-specific single pup primary astrocyte cultures from wild-type (WT) and aromatase-knockout (ArKO) mice. After determining sex by external and internal examination as well as PCR and genotype by PCR amplification of tail cDNA, we established cultures from 1-3-day-old male and female WT and ArKO mice pups and grew them to confluence in estrogen-free media. Cell death was measured by lactate dehydrogenase (LDH) assay. Our study shows that, while WT female astrocytes are more resistant to OGD than WT male cells, sex differences disappear in ArKO cells. Cell death is significantly increased in ArKO compared to WT in female astrocytes but not male cells. Therefore, P450 aromatase appears to be essential in endogenous neuroprotection in females, and this finding may have clinical implications. This innovative technique may also be applied to other in vitro studies of sex-related functional differences.

GPR30 contributes to estrogen-induced thymic atrophy

The mechanisms by which prolonged estrogen exposures, such as estrogen therapy and pregnancy, reduce thymus weight, cellularity, and CD4 and CD8 phenotype expression, have not been well defined. In this study, the roles played by the membrane estrogen receptor, G protein-coupled receptor 30 (GPR30), and the intracellular estrogen receptors, estrogen receptor alpha (ERalpha) and beta (ERbeta), in 17beta-estradiol (E2)-induced thymic atrophy were distinguished by construction and the side-by-side comparison of GPR30-deficient mice with ERalpha and ERbeta gene-deficient mice. Our study shows that whereas ERalpha mediated exclusively the early developmental blockage of thymocytes, GPR30 was indispensable for thymocyte apoptosis that preferentially occurs in T cell receptor beta chain(-/low) double-positive thymocytes. Additionally, G1, a specific GPR30 agonist, induces thymic atrophy and thymocyte apoptosis, but not developmental blockage. Finally, E2 treatment attenuates the activation of nuclear factor-kappa B in CD25(-)CD4(-)CD8(-) double-negative thymocytes through an ERalpha-dependent yet ERbeta- and GPR30-independent pathway. Differential inhibition of nuclear factor-kappaB by ERalpha and GPR30 might underlie their disparate physiological effects on thymocytes. Our study distinguishes, for the first time, the respective contributions of nuclear and membrane E2 receptors in negative regulation of thymic development.

Inhalational anesthetics as preconditioning agents in ischemic brain

While many pharmacological agents have been shown to protect the brain from cerebral ischemia in animal models, none have translated successfully to human patients. One potential clinical neuroprotective strategy in humans may involve increasing the brain's tolerance to ischemia by preischemic conditioning (preconditioning). There are many methods to induce tolerance via preconditioning such as ischemia itself, pharmacological, hypoxia, endotoxin, and others. Inhalational anesthetic agents have also been shown to result in brain preconditioning. Mechanisms responsible for brain preconditioning are many, complex, and unclear and may involve Akt activation, ATP-sensitive potassium channels, and nitric oxide, amongst many others. Anesthetics, however, may play an important and unique role as preconditioning agents, particularly during the perioperative period.

Gender-specific response to isoflurane preconditioning in focal cerebral ischemia

Inhalation anesthetics are effective chemical preconditioning agents in experimental cerebral ischemia. However, previous work has been performed exclusively in male animals. We determined if there is a gender difference in ischemic outcome after isoflurane preconditioning (IsoPC), and if this sex-specific response is linked to differences in Akt phosphorylation or expression of neuronal inducible cell-death putative kinase (NIPK), a negative modulator of Akt activation. Young and middle-aged male and female mice were preconditioned for 4 h with air (sham PC) or 1.0% IsoPC and recovered for 24 h. Cortices were subdissected from preconditioned young male and female mice for measurement of Akt phosphorylation (Western blot) and NIPK mRNA (quantitative polymerase chain reaction). Additional cohorts underwent 2 h of reversible middle cerebral artery occlusion. Lastly, male and female Akt1(+/+) and Akt1(-/-) mice were studied to determine if gender differences in ischemic outcome after IsoPC is Akt1-dependent. Infarction volume was determined at 22 h reperfusion (2,3,5-triphenyltetrazolium chloride). As expected, IsoPC decreased ischemic damage as compared with sham PC in young and middle-aged male mice. In contrast, IsoPC markedly increased infarction in young female mice and had no effect in middle-aged female mice. Cortical phospho-Akt was increased by IsoPC versus sham PC only in male mice. No increase was observed in IsoPC female mice. NIPK mRNA was higher in female mice than in male mice regardless of preconditioning status. Male IsoPC neuroprotection was lost in Akt1-deficient male mice. We conclude that IsoPC is beneficial only in ischemic male brain and that sex differences in IsoPC are mediated through Akt activation and basal NIPK expression.

Inhalational anesthetics as neuroprotectants or chemical preconditioning agents in ischemic brain

This review will focus on inhalational anesthetic neuroprotection during cerebral ischemia and inhalational anesthetic preconditioning before ischemic brain injury. The limitations and challenges of past and current research in this area will be addressed before reviewing experimental and clinical studies evaluating the effects of inhalational anesthetics before and during cerebral ischemia. Mechanisms underlying volatile anesthetic neuroprotection and preconditioning will also be examined. Lastly, future directions for inhalational anesthetics and ischemic brain injury will be briefly discussed.

The laboratory animal boards study group: A multifaceted tool for preparation for the American College for Laboratory Medicine board examination

Preparation for the specialty board examination for the American College of Laboratory Animal Medicine (ACLAM) is an intensive process that is facilitated by geographic regions where many people studying for the exam are located in close proximity. However, many people work at institutions that are distant from these 'study centers'. Approximately 10 y ago, the Laboratory Animal Boards Study Group (LABSG) online journal club was established to provide a forum for journal review for examination preparation. Over the years, the mission of this group has expanded to include practice examinations and practicals, questions from common resources, and summaries and questions from common laboratory animal science journals. These study aids are beneficial for those preparing for the ACLAM certification examination. They are also beneficial for those preparing for the technician and manager certification examinations offered by the American Association for Laboratory Animal Science (AALAS). This article is intended to be an introduction to the variety of study aids available through the LABSG online journal review club and the LABSG web page (www.labsg.org). It also provides details on the demographics of participants and an exploration of how this resource enhances examination preparation.

A G-protein-coupled estrogen receptor is involved in hypothalamic control of energy homeostasis

Estrogens are involved in the hypothalamic control of multiple homeostatic functions including reproduction, stress responses, energy metabolism, sleep cycles, temperature regulation, and motivated behaviors. The critical role of 17beta-estradiol (E2) is evident in hypoestrogenic states (e.g., postmenopause) in which many of these functions go awry. The actions of E2 in the brain have been attributed to the activation of estrogen receptors alpha and beta through nuclear, cytoplasmic, or membrane actions. However, we have identified a putative membrane-associated estrogen receptor that is coupled to desensitization of GABAB and mu-opioid receptors in guinea pig and mouse hypothalamic proopiomelanocortin neurons. We have synthesized a new nonsteroidal compound, STX, which selectively targets the Galphaq-coupled phospholipase C-protein kinase C-protein kinase A pathway, and have established that STX is more potent than E2 in mediating this desensitization in an ICI 182, 780-sensitive manner in both guinea pig and mouse neurons. Both E2 and STX were fully efficacious in estrogen receptor alpha,beta knock-out mice. Moreover, in vivo treatment with STX, similar to E2, attenuated the weight gain in hypoestrogenic female guinea pigs. Therefore, this membrane-delimited signaling pathway plays a critical role in the control of energy homeostasis and may provide a novel therapeutic target for treatment of postmenopausal symptoms and eating disorders in females.

Estradiol alters only GAD67 mRNA levels in ischemic rat brain with no consequent effects on GABA

The present study tested the hypothesis that estradiol reduces tissue infarction after middle cerebral artery occlusion (MCAO) in estradiol-deficient females by augmenting glutamic acid decarboxylase (GAD) expression and thus activity, leading to increases in gamma-amino-butyric acid (GABA) tissue levels. Glutamic acid decarboxylase is the principal enzyme for GABA synthesis and has two isoforms, GAD65 and GAD67, which differ in size and cellular distribution. Rats were ovariectomized 7 to 8 days before receiving no hormone, placebo, or 25 microg estradiol via subcutaneous implant 7 to 10 days before harvesting tissue in either ischemic cohorts after 2 h of MCAO (end-ischemia) or in nonischemic cohorts. Selected cortical and striatal regions were microdissected from harvested brains. GAD65/67 mRNA levels were determined by microlysate ribonuclease protection assay. End-ischemic GABA concentrations were determined by HPLC. Steroid treatment selectively decreased ischemic cortical GAD67 mRNA levels. In most brain regions evaluated, regional GABA concentrations increased with ischemia regardless of treatment. Estradiol blocked MCAO-induced increases in GABA concentration only in dorsomedial cortex. These data suggest that estradiol repletion in ischemic rat brain selectively decreases GAD67 mRNA levels but does not alter steady-state GABA concentrations. It may be that estradiol under ischemic conditions is attenuating GABA metabolism rather than enhancing synthesis or is augmenting other aspects of GABAergic transmission such as GABA transporters and receptors.

Effects of estrogen on platelet reactivity after transient forebrain ischemia in rats

Estrogen's prothrombotic effects are of increasing concern, particularly in stroke risk and recovery. Using an ischemic rodent model, the authors sought to determine (a) if estrogen replacement increases postischemic platelet reactivity, (b) if changes in estrogen status alter intraplatelet endothelial nitric oxide synthase (eNOS) synthesis, and (c) if estrogen-mediated effects on platelets alter cerebral blood flow during reperfusion. Intact (I), ovariectomized (OVX), and OVX + 17 beta-estradiol (E50) rats were subjected to 30 min of forebrain ischemia and 60 min of reperfusion. Using the platelet activation marker P-selectin, postischemic platelet reactivity was quantified by flow cytometry. In a separate cohort (I, OVX, E50), the authors quantified platelet eNOS by Western blot. Another cohort (OVX, E50) was subjected to ischemia/reperfusion, and cerebral blood flow was determined using the iodoantipyrine technique. Collagen-stimulated platelet P-selectin expression was increased in the OVX rats at 60 min of reperfusion, and this effect was reversed by estrogen treatment. No differences in platelet eNOS expression were detected among groups. Cerebral blood flow at 60 min reperfusion was comparable between the OVX and the E50 rats. The authors conclude that during reper-fusion, estrogen deficiency increases postischemic platelet sensitivity to stimuli in estrogen-deficient rats. Estrogen treatment mitigates effects of estrogen loss on platelets, but this early effect is apparently not caused by intraplatelet eNOS depression. Neither estrogen deficiency nor estrogen treatment changes early postischemic regional brain blood flow. In this rodent global cerebral ischemic model, physiologic doses of estrogen are not deleterious to platelet reactivity and may initially reduce postischemic platelet reactivity.

Lack of correlation of vaginal impedance measurements with hormone levels in the rat

Hormone levels vary in female rats depending on estrous cycle stage. Vaginal cytology is a reliable method of staging female rats, but vaginal impedance offers an alternative depending on application. We sought to correlate vaginal impedance in cycling female rats with hormone levels. Vaginal cytology was the standard for comparison and verification of estrous cycle stage. Female rats (n = 41) were evaluated twice daily for 15 days via vaginal cytology and impedance to evaluate two or three estrous cycles per rat. During the last 5 days of the study, selected anesthetized sampling groups (n = 3 or 4 rats per group) were bled terminally at each time point to allow hormone determinations concurrently with vaginal cytology and impedance. Rats with abnormal vaginal smears or discharges (n = 5) were evaluated for reproductive tract histology. Rats classified in estrus by vaginal cytology had significantly higher vaginal impedance values than did nonestrus rats, but vaginal impedance and estrous cycle stage as determined by vaginal cytology did not correlate. Because of small sampling size in nonproestrus groups, correlation between vaginal impedance and hormone levels was evaluated only in proestrus rats (n = 22) and was nonsignificant. No correlation occurred between vaginal impedance and hormone levels in unstaged rats (n = 41). Two animals evaluated for reproductive tract histology showed evidence of pseudopregnancy. Vaginal impedance may be useful in distinguishing estrus from nonestrus rats but may be limited for chronic estrous cycle monitoring because of the possible risk of inducing pseudopregnancy.

Animal models of ischemic stroke: balancing experimental aims and animal care

Animal models of ischemic stroke are examples of an induced model that can present challenges from the perspectives of protocol review and animal management. The review presented here will include a brief summary of the current state of knowledge about clinical stroke; a general synopsis of important unanswered research questions that justify use of animal stroke models; an overview of various animal models of ischemic stroke, including strengths and limitations; and a discussion of animal care issues relative to ischemic stroke models. Good communication and interactive education among primary investigators, laboratory animal veterinarians and caretakers, and institutional animal care and use committee members are critical in achieving a balance between research objectives and animal care issues when using animal stroke models.

Effects of combined estrogen and progesterone on brain infarction in reproductively senescent female rats

Recent data from the Women's Health Initiative have highlighted many fundamental issues about the utility and safety of long-term estrogen use in women. Current hormone replacement therapy for postmenopausal women incorporates progestin with estrogen, but it is uncertain if combined therapy provides major cerebrovascular risks or benefits to these women. No experimental animal stroke studies have examined combined hormone administration. The authors tested the hypothesis that combined hormone treatment reduces ischemic injury in middle-aged female rat brain. Reproductively senescent female rats underwent 2-hour middle cerebral artery occlusion (MCAO) followed by 22 hours reperfusion. Estrogen implants were placed subcutaneously at least 7 days before MCAO, and progesterone intraperitoneal injections were given 30 minutes before MCAO, at initiation, and at 6 hours of reperfusion. Rats received no hormone, a 25-microg estrogen implant, a 25-microg estrogen implant plus 5 mg/kg intraperitoneal progesterone, or 5 mg/kg intraperitoneal progesterone. Cortical, caudoputamen, and total infarct volumes were assessed by 2,3,5-triphenyltetrazolium chloride staining and digital image analysis at 22 hours reperfusion. Cortical and total infarct volumes, except in the acute progesterone-treated group, were significantly attenuated in all estrogen-alone and combined hormone-treated groups. There were no significant differences in caudoputamen infarct volumes in all hormone-treated groups as compared with untreated rats. These data have potential clinical implications relative to stroke for postmenopausal women taking combined hormone replacement therapy.