Erythropoietin protects CA1 neurons against global cerebral ischemia in rat: potential signaling mechanisms

Erythropoietin (EPO) is a hormone that is neuroprotective in models of neurodegenerative diseases. This study examined whether EPO can protect against neuronal death in the CA1 region of the rat hippocampus following global cerebral ischemia. Recombinant human EPO was infused into the intracerebral ventricle either before or after the induction of ischemia produced by using the four-vessel-occlusion model in rat. Hippocampal CA1 neuron damage was ameliorated by infusion of 50 U EPO. Administration of EPO was neuroprotective if given 20 hr before or 20 min after ischemia, but not 1 hr following ischemia. Coinjection of the phosphoinositide 3 kinase inhibitor LY294002 with EPO inhibited the protective effects of EPO. Treatment with EPO induced phosphorylation of both AKT and its substrate, glycogen synthase kinase-3beta, in the CA1 region. EPO also enhanced the CA1 level of brain-derived neurotrophic factor. Finally, we determined that ERK activation played minor roles in EPO-mediated neuroprotection. These studies demonstrate that a single injection of EPO ICV up to 20 min after global ischemia is an effective neuroprotective agent and suggest that EPO is a viable candidate for treating global ischemic brain injury.     

Using Perceptual Signatures to Define and Dissociate Condition-Specific Neural Etiology: Autism and Fragile X Syndrome as Model Conditions

The functional link between genetic alteration and behavioral end-state is rarely straightforward and never linear. Cases where neurodevelopmental conditions defined by a distinct genetic etiology share behavioral phenotypes are exemplary, as is the case for autism and Fragile X Syndrome (FXS). In this paper and its companion paper, we propose a method for assessing the functional link between genotype and neural alteration across these target conditions by comparing their perceptual signatures. In the present paper, we discuss how such signatures can be used to (1) define and differentiate various aspects of neural functioning in autism and FXS, and subsequently, (2) to infer candidate causal (genetic) mechanisms based on such signatures (see companion paper, this issue).     

Recurrence of Type 1 Diabetes After Simultaneous Pancreas-Kidney Transplantation, Despite Immunosuppression, Is Associated With Autoantibodies and Pathogenic Autoreactive CD4 T-Cells

OBJECTIVE

To investigate if recurrent autoimmunity explained hyperglycemia and C-peptide loss in three immunosuppressed simultaneous pancreas-kidney (SPK) transplant recipients.

RESEARCH DESIGN AND METHODS

We monitored autoantibodies and autoreactive T-cells (using tetramers) and performed biopsy. The function of autoreactive T-cells was studied with in vitro and in vivo assays.

RESULTS

Autoantibodies were present pretransplant and persisted on follow-up in one patient. They appeared years after transplantation but before the development of hyperglycemia in the remaining patients. Pancreas transplant biopsies were taken within ∼1 year from hyperglycemia recurrence and revealed β-cell loss and insulitis. We studied autoreactive T-cells from the time of biopsy and repeatedly demonstrated their presence on further follow-up, together with autoantibodies. Treatment with T-cell–directed therapies (thymoglobulin and daclizumab, all patients), alone or with the addition of B-cell–directed therapy (rituximab, two patients), nonspecifically depleted T-cells and was associated with C-peptide secretion for >1 year. Autoreactive T-cells with the same autoantigen specificity and conserved T-cell receptor later reappeared with further C-peptide loss over the next 2 years. Purified autoreactive CD4 T-cells from two patients were cotransplanted with HLA-mismatched human islets into immunodeficient mice. Grafts showed β-cell loss in mice receiving autoreactive T-cells but not control T-cells.

CONCLUSIONS

We demonstrate the cardinal features of recurrent autoimmunity in three such patients, including the reappearance of CD4 T-cells capable of mediating β-cell destruction. Markers of autoimmunity can help diagnose this underappreciated cause of graft loss. Immune monitoring during therapy showed that autoimmunity was not resolved by the immunosuppressive agents used.Type 1 diabetes is an autoimmune disease characterized by the lymphocytic infiltration of the pancreatic islets (insulitis), β-cell destruction, and loss of insulin secretion (1). Autoreactive CD4 and CD8 T-cells and autoantibodies to islet cell autoantigens are detected in patients and pre-diabetic subjects, often preceding diabetes onset by months to years. Insulin, GAD (GAD, 65-kDa isoform), the tyrosine-like phosphatase protein IA-2, the islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP), and the recently identified cation efflux transporter ZnT8 are well characterized and commonly targeted autoantigens (2–8).Simultaneous pancreas-kidney (SPK) transplantation from deceased donors restores insulin secretion in patients and corrects end-stage renal disease (9). Immunological failures occur in a minority of transplant recipients and are usually categorized as chronic rejection. Another possible cause of immunological failure is recurrence of type 1 diabetes. This was initially reported a few weeks after transplantation in recipients of the tail of the pancreas from living-related HLA-identical twins or siblings who, because of HLA matching, received either no or reduced immunosuppression (10–13). However, diabetes recurrence was <10% in a large series of recipients of deceased donor grafts given immunosuppression sufficient to prevent rejection (14). Further studies associated islet cell autoantibodies with graft failure (15–19) but lacked biopsy data, and rejection was not excluded. Two SPK recipients had partial evidence for diabetes recurrence (20), including limited biopsy data showing selective β-cell loss and/or insulitis and limited autoantibody data (20). None of these studies assessed autoantigen-specific T-cells in the context of graft loss. Islet autoimmunity is considered rare and is not routinely monitored in SPK recipients. Thus, recurrence of type 1 diabetes in SPK recipients remains incompletely characterized.We investigated whether recurrent islet autoimmunity explained the hyperglycemia and loss of insulin secretion observed in three immunosuppressed SPK recipients in the absence of rejection. The immunological assessment included both retrospective and prospective testing for autoantibodies and prospective testing for autoantigen-specific T-cells. Monitoring was continued on extended follow-up after patients were diagnosed with recurrence of type 1 diabetes and received additional immunotherapy to antagonize the autoimmune process. We also characterized the functional features of the autoreactive T-cells detected in these patients in the context of recurring diabetes, using both in vitro and in vivo experimental assays to test the pathogenic effects of the autoreactive T-cells.     

Differences in exposure and biological markers of fluoride among White and African American children

Objective: To determine differences in self‐reported fluoride exposure and fluoride exposure biomarkers between two racial groups. Methods: Questionnaires regarding fluoride exposure, urine and water collection kits were distributed to African American and White 7‐14‐year‐old children. Children received a dental exam for fluorosis. Water, urine, and saliva were analyzed for fluoride content. Questionnaire responses and results of sample analyses were compared and observed differences were analyzed. Results: 83 African American and 109 White children completed the study. Dental fluorosis was observed in 62.5 percent White and 80.1 percent African American children. Significant differences were found for fluorosis prevalence and severity between the groups (P < 0.05). Less African American children reported having used fluoride supplements in the past. White children began brushing their teeth at an earlier age. More White children visited a dentist for the first time before age 3. African American children reported currently using larger amounts of toothpaste. More Whites than African Americans had received topical fluoride treatments over the previous year. All of these differences were significant. Multivariate models showed that supplement use and amount of toothpaste used for brushing had significant associations to a child's fluorosis scores. Fluoride concentration of water and saliva was not different for the two groups; however, the fluoride content in urine was significantly higher in African Americans than in Whites [P < 0.05; 1.40 ± standard deviation (SD) 0.65 ppm versus 1.08 ± SD 0.28 ppm]. Conclusions: Differences in fluoride exposure between two racial groups were observed. These differences are complex and need to be better defined.     

Screening for thrombophilia and antithrombotic prophylaxis in pregnancy: Guidelines of the Italian Society for Haemostasis and Thrombosis (SISET)

The term thrombophilia describes an increased tendency to develop thrombosis and many laboratory markers with different strengths of association with thrombosis have been identified. The main causes of maternal mortality and morbidity in developed countries is venous thromboembolism (VTE) and obstetric complications. During pregnancy and puerperium the risk for VTE increases due to hemostatic imbalance towards a prothrombotic state, and it is further increased in women carriers of thrombophilia; recent studies have also demonstrated an association between thrombophilia and obstetric complications. These complications are, therefore, considered potentially preventable with the prophylactic administration of anticoagulant drugs, although their efficacy is not proven by data from randomized controlled trials. After a systematic comprehensive literature review and using a rigorous methodology, the expert panel formulated recommendations regarding the usefulness of screening for thrombophilia in pregnancy to identify high-risk women and for the management of antithrombotic prophyalxis. When evidence is lacking, consensus-based recommendations are provided.     

Influence of platelet reactivity and response to clopidogrel on myocardial damage following percutaneous coronary intervention in patients with non-st-segment elevation acute coronary syndrome

Introduction

A wide variability in the response to clopidogrel and magnitude of post-treatment platelet reactivity has been described. However, this has been demonstrated by light transmittance aggregometry, a method too laborious for daily practice. Point-of-care devices may overcome this limitation, but little is known on the predictive value of such measurements. Our objective was to determine the relationship between platelet reactivity and the incidence of myocardial damage following percutaneous coronary intervention (PCI) in patients with Non-ST-segment Elevation Acute Coronary Syndrome (NSTEACS).

Materials and Methods

This prospective study included 93 patients with NSTEACS and PCI. All patients received a loading dose of 300 mg of clopidogrel and 250 mg of aspirin. Myocardial damage was defined as any elevation above upper limit of normal or previous levels of troponin T, assessed every 6 h for at least 24 h following PCI. Platelet reactivity not related to clopidogrel (BASE reactivity), related to P2Y12 inhibition (P2Y12 reactivity) and inhibition of platelet aggregation (IPA) were assessed immediately pre-PCI with the VerifyNow® device.

Results

Myocardial damage was detected in 60 patients (64.5%). Higher BASE reactivity was associated with myocardial damage (287.8 ± 62.6 vs. 260 ± 55.9 units, p = 0.043) while a trend was found for P2Y12 reactivity (173.4 ± 70.3 vs. 149.2 ± 58.4 units, p = 0.109). No relationship was detected for IPA. Multivariate logistic regression analysis confirmed that BASE reactivity (p = 0.04) and P2Y12 reactivity (p = 0.03) were independent predictors of myocardial damage.

Conclusions

Platelet reactivity before PCI appears to be better predictor of myocardial damage than does response to clopidogrel.     

Is the distance between mammillary bodies predictive of a thickened third ventricle floor?

Object The aim of this study was to correlate intraoperative endoscopic third ventriculostomy (ETV) findings in hydrocephalic patients with the MR imaging appearance of the mammillary bodies (MBs), the fundamental anatomical landmarks of the third ventricle floor (TVF) region. Methods The authors reviewed brain MR images and intraoperative ETV records in 23 patients with hydrocephalus as well as MR imaging data from 120 randomized control volunteers of various ages to define the normal intermammillary distance (IMD). Results In control volunteers, no measurable IMD ("kissing" configuration) was observed in 91 (85%) of 107 cases, and there was mild MB splitting (mean +/- standard deviation, 0.18 +/- 0.12 cm) in only 16 cases with age-related cerebral atrophy. Among the 21 patients with complete MR imaging and ETV data sets, 12 ETV procedures were hindered by anatomical anomalies such as a thickened TVF or an "upward ballooning" phenomenon. On preoperative MR imaging in these 12 patients, there was an increased IMD (0.55 +/- 0.41 cm) compared with that in the remaining 9 patients (0.27 +/- 0.25 cm) who had a normal thin TVF during ETV and in the control group (0.03 +/- 0.08 cm). Magnetic resonance imaging and ETV data concordantly displayed nonsplit MBs in 6 of 9 cases with a thin TVF and split MBs in 10 of 12 cases with a thick TVF. Conclusions The normal configuration of MBs is no measurable IMD, with mild splitting occurring in patients with age-related brain atrophy. In hydrocephalic patients, a thickened TVF was present almost exclusively with an increased IMD on preoperative MR imaging and separated MBs on endoscopic viewing. Large retrospective series are needed to confirm that a preoperative increased IMD is predictive of a thickened TVF during ETV.