Reticulocytes bearing C4d as biomarkers of disease activity for systemic lupus erythematosus

OBJECTIVE: There is an urgent need for biomarkers with which to monitor disease activity in patients with systemic lupus erythematosus (SLE). We recently showed that abnormal levels of C4d, an activation-derived fragment of complement component C4, are deposited on the surface of erythrocytes from patients with SLE. This study focused on reticulocytes, the youngest and shortest-lived erythrocytes (lifespan 24-48 hours), with the objective of testing our hypothesis that when reticulocytes emerge from the bone marrow, they are immediately exposed to and acquire C4d at levels proportionate to the extent of complement activation at that time, thereby reflecting disease activity in SLE. METHODS: We conducted a cross-sectional study of 156 patients with SLE, 140 patients with other diseases, and 159 healthy controls. Levels of C4d on the surface of reticulocytes were examined using a 2-color flow cytometric assay. The results were analyzed for correlations with SLE disease activity. RESULTS: A wide range of increased levels of reticulocyte C4d was specifically detected in SLE patients. These levels fluctuated in SLE patients and correlated with clinical disease activity, as determined by the Safety of Estrogens in Lupus Erythematosus: National Assessment (SELENA) version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and the Systemic Lupus Activity Measure (SLAM). Specifically, in cross-sectional analyses, patients with reticulocyte C4d levels in the highest quartile compared with those in the lowest quartile had significantly higher SELENA-SLEDAI (P = 0.00002) and SLAM (P = 0.02) scores. Longitudinal observation demonstrated that the reticulocyte C4d levels changed in relation to the clinical course in individual patients. CONCLUSION: These findings support our hypothesis that C4d-bearing reticulocytes may serve as biomarkers of disease activity in patients with SLE.     

Differences in the management and prognosis of women and men who suffer from acute coronary syndromes.

OBJECTIVES: The purpose of this research was to determine if sex and gender differences in the management of acute coronary syndromes (ACS) are associated with differences in prognosis after ACS. BACKGROUND: Previous investigators have reported sex/gender differences in the management of patients with ACS, but the impact of these differences on prognosis is unclear. METHODS: We analyzed data from the Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) trial, which enrolled 4,836 women and 7,726 men with ACS. Patients were classified into risk strata using the Thrombolysis In Myocardial Infarction (TIMI) score. RESULTS: Women underwent fewer invasive procedures including angiography, angioplasty, and coronary artery bypass graft (CABG) surgery (47.6% vs. 60.5%; p = 0.0001) compared to men. No significant differences in cardiovascular death, myocardial infarction (MI), or stroke were observed (9.8% vs. 10.9%; p = 0.04), although women were more likely than men to develop refractory ischemia and to be rehospitalized for chest pain during follow-up (16.6% vs. 13.9%; p = 0.0001). These differences were particularly evident among TIMI high-risk women. A significant interaction between TIMI risk and gender for the outcome of refractory angina and rehospitalization for angina was present. CONCLUSIONS: Compared to men, high-risk women with ACS undergo less coronary angiography, angioplasty, and CABG surgery, and while they do not have higher incidence cardiovascular death, recurrent MI, or stroke, they suffer an increased rate of refractory ischemia and rehospitalization. All high-risk women and men with ACS should receive optimal medical management, and be considered for coronary angiography with possible revascularization if their coronary anatomy warrants it.     

Brief report: Risk factors for pneumococcal vaccine refusal in adults

Background: Invasive pneumococcal disease is a significant cause of morbidity and mortality in the United States. Despite availability of an effective vaccine, many patients refuse vaccination.
Objective: To investigate patient characteristics and features of the patient–provider relationship associated with pneumococcal vaccine refusal.
Design: Case–control study using chart review.
Patients: Five hundred adults from the medical clinics of a 1,000-bed inner-city teaching hospital.
Measurements and Main Results: Independent risk factors for pneumococcal vaccine refusal included patient–provider gender discordance (odds ratio (OR)=2.09, 95% confidence interval (CI) 1.07 to 4.09); a visit to a not-usual provider at the time of vaccine offering (OR=2.26, 95% CI 1.13 to 4.49); never having received influenza vaccination (OR=7.44, 95% CI 3.76 to 14.76); prior pneumococcal vaccine refusals (OR=3.45, 95% CI 1.60 to 7.43); and a history of ever having refused health maintenance tests (OR=2.86, 95% CI 1.40 to 5.84).
Conclusions: We have identified both patient factors and factors related to the patient–provider relationship that are risk factors for pneumococcal vaccine refusal. By identifying patients at risk for pneumococcal vaccine refusal, efforts to increase vaccination rates can be better targeted.     

Developmental synaptic regulator,TWEAK/Fn14 signaling,is a determinant of synaptic function in models of stroke and neurodegeneration

Identifying molecular mediators of neural circuit development and/or function that contribute to circuit dysfunction when aberrantly reengaged in neurological disorders is of high importance. The role of the TWEAK/Fn14 pathway, which was recently reported to be a microglial/neuronal axis mediating synaptic refinement in experience-dependent visual development, has not been explored in synaptic function within the mature central nervous system. By combining electrophysiological and phosphoproteomic approaches, we show that TWEAK acutely dampens basal synaptic transmission and plasticity through neuronal Fn14 and impacts the phosphorylation state of pre- and postsynaptic proteins in adult mouse hippocampal slices. Importantly, this is relevant in two models featuring synaptic deficits. Blocking TWEAK/Fn14 signaling augments synaptic function in hippocampal slices from amyloid-beta–overexpressing mice. After stroke, genetic or pharmacological inhibition of TWEAK/Fn14 signaling augments basal synaptic transmission and normalizes plasticity. Our data support a glial/neuronal axis that critically modifies synaptic physiology and pathophysiology in different contexts in the mature brain and may be a therapeutic target for improving neurophysiological outcomes.

Neural circuit patterning, refinement, and plasticity are enabled by the dynamic strengthening, weakening, and pruning of chemical synapses in response to circuit activity. However, synapse loss and reduced plasticity are early hallmarks of chronic neurological disorders such as autism, schizophrenia and Alzheimer’s disease (AD) (1–3). It is therefore hypothesized that the underlying molecular mechanisms of pruning, although normally balanced in health, are dysregulated in disease. Particularly interesting is the notion that the mechanisms responsible for the reduction in functional synapses in disease reflect the aberrant reactivation of pathways important for synapse elimination in development. For example, in an AD model, synapse elimination was shown to be mediated by the complement pathway in the hippocampus (HC), reflecting aberrant reactivation of complement-dependent synapse elimination that occurs in the dorsal lateral geniculate nucleus (dLGN) of the thalamus during visual development (4). In such a paradigm, the reactivation of developmental mechanisms enables pathways that can act universally across different ages, circuits, and brain regions. Thus, the mechanisms underlying normal circuit development and their potential reactivation as key contributors to neurological diseases are areas of deep interest.In addition to chronic neurological disorders, circuitry changes also occur in acute ischemic stroke, the second leading cause of death worldwide and a cause of debilitating long-term disability. Interruptions in blood flow that deprive neurons of oxygen and nutrients result in significant cell death, followed by deficits in neurophysiological activity that are associated with poor motor recovery (5). Remarkably, the adult brain can undergo some degree of spontaneous poststroke recovery, apparently by engaging neuroplasticity mechanisms including remapping, synaptogenesis, and synaptic strengthening (5, 6). Despite these adaptations, over half of ischemic stroke patients fail to recover completely and continue to experience persistent long-term disability (7). The underlying signaling pathways that regulate synaptic physiology after stroke are an active topic of investigation.TNF-like weak inducer of apoptosis (TWEAK) protein, originally discovered as a cytokine produced by macrophages (8), signals through its injury-inducible transmembrane receptor, FGF-inducible molecule-14 (Fn14) (9). Consequently, the function of TWEAK/Fn14 signaling was elucidated as a driver of tissue remodeling in contexts of injury and disease in a variety of organ systems (10). Recently, findings have suggested a role for the TWEAK/Fn14 pathway in the central nervous system (CNS). Namely, several compelling observations indicate that TWEAK signaling through Fn14 might be a key molecular modulator of synaptic function in contexts of neurological challenge. TWEAK and Fn14 are up-regulated in the CNS in AD (11, 12, 13 and SI Appendix, Fig. S6A) and after ischemic stroke in humans and mice (14–16). Importantly, TWEAK/Fn14 signaling was also recently shown to be a pathway necessary for synapse maturation during experience-dependent visual development. Light-induced up-regulation of Fn14 in thalamocortical excitatory neurons and corresponding up-regulation of TWEAK in microglia mediate the elimination of weak synapses and strengthening of remaining synapses in the dLGN (17, 18). Indeed, the communication between neurons and supporting microglia has emerged as a key mechanism regulating neuronal circuitry, with microglia deploying their ramified processes to continuously survey and refine synapses in response to neural activity. Interestingly, TWEAK expression has also been shown to be microglia-enriched in the mouse cortex (19), suggesting that it may play a role in multiple brain regions. Thus, like the complement pathway, the TWEAK/Fn14 pathway could be an important regulator of synapse biology in visual development which is re-engaged and acts generally in different ages and brain regions to contribute to pathology.The involvement of TWEAK/Fn14 signaling in synapse physiology or pathophysiology outside of the developing visual system is unknown. We considered it to be a strong candidate modifier of synaptic function in adults given that Fn14 is up-regulated and required for synaptic refinement in experience-dependent visual development, and TWEAK and Fn14 are up-regulated in contexts of neurological injury/disease, suggesting that the TWEAK/Fn14 system is tuned to periods of substantial change in neuronal activity levels or environment (e.g., eye opening, ischemic stroke). We employed HC slices to test the hypothesis that the TWEAK/Fn14 pathway regulates synaptic function in adult mice and in different disease contexts and delineate its mechanism of action. Herein, we reveal that TWEAK, through neuronal Fn14, mediates acute dampening of basal synaptic transmission and synaptic plasticity in hippocampal slices from mature mice. Furthermore, we demonstrate that TWEAK/Fn14 signaling broadly impacts the phosphorylation state of critical synaptic proteins, suggesting a general role in synapse modulation. Finally, we show that pathway deficiency or pharmacological inhibition of TWEAK/Fn14 signaling augments synaptic transmission and plasticity in amyloid-beta (Aβ)–overexpressing mice and post ischemic stroke animals, two model systems featuring synaptic functional deficits. Thus, our results support that TWEAK/Fn14 constitutes a synaptic regulatory pathway with therapeutic potential for CNS disorders in the adult brain.     

The relationship between blood pressure and C-reactive protein in the Multi-Ethnic Study of Atherosclerosis (MESA).

OBJECTIVES: The goal of this study was to determine the relationship between resting blood pressure (BP) and C-reactive protein (CRP) in a multi-ethnic cohort of men and women from the Multi-Ethnic Study of Atherosclerosis (MESA). BACKGROUND: Several investigators have observed elevated levels of CRP in individuals with hypertension. Hypertension prevalence varies considerably across ethnic groups. Important questions remain regarding whether the relationship between hypertension and CRP is similar across ethnic and gender subgroups. METHODS: The MESA participants had CRP levels determined at the baseline clinical examination (N = 6,814). Hypertension, treated as a dichotomous variable (yes/no), was defined as a systolic or diastolic BP > or =140/90 mm Hg or a self-reported history of hypertension and use of antihypertensive medications. RESULTS: The geometric mean CRP in hypertensive participants was 2.3 +/- 0.07 mg/l compared with 1.6 +/- 0.07 mg/l among normotensive participants (p < 0.0001). The relative difference in CRP levels in hypertensives compared with normotensives was similar regardless of gender (13% in men and 13% in women). Ethnic comparisons showed that Chinese participants had the lowest CRP concentration but the largest difference in CRP by hypertension status (24%). Caucasians and African Americans had 10% to 15% higher CRP levels with hypertension, whereas Hispanics had no significant difference in CRP by hypertension status. CONCLUSIONS: This study confirms the existence of an independent association between hypertension and inflammation in both men and women. Ethnic group differences were evident, with the strongest association observed in Chinese participants and no difference in CRP levels by hypertension status in Hispanics.     

Indeterminate colitis: the real story

PURPOSE: Up to one in five patients undergoing surgery for ulcerative colitis will have ambiguous histology, with features of both ulcerative colitis and Crohn's disease, and are categorized as having indeterminate colitis. We hypothesized that functional outcomes in indeterminate colitis patients undergoing ileal pouch-anal anastomosis are comparable with those of ulcerative colitis patients undergoing ileal pouch-anal anastomosis. METHODS: Physician-conducted interviews of 120 consecutive ileal pouch-anal anastomosis patients with a preoperative diagnosis of ulcerative colitis were reviewed, with a mean follow-up of 54 months. All colectomy specimens were reviewed by a single pathologist. Any changes in histologic diagnosis from ulcerative colitis to indeterminate colitis or Crohn's disease, frequency of postoperative complications, pouch function, and long-term postoperative medication usage were recorded. RESULTS: Although postoperative fistulas were more common in indeterminate colitis than ulcerative colitis (26 vs. 10 percent; P = 0.02, chi-squared), no indeterminate colitis patient required a permanent ileostomy as compared with six ulcerative colitis patients. Long-term functional results were similar. Overall, two-thirds of patients developed pouchitis. Ulcerative colitis and Crohn's disease patients were more likely to have had >3 episodes of pouchitis (58 and 72 percent) compared with indeterminate colitis patients (29 percent; P = 0.006, chi-squared). A greater number of Crohn's disease patients required maintenance oral antibiotic therapy (64 percent) to achieve satisfactory functional results compared with both indeterminate colitis and ulcerative colitis patients (20 and 28 percent; P = 0.014, chi-squared). CONCLUSIONS: Although ileal pouch-anal anastomosis patients with indeterminate colitis have more postoperative fistulas, long-term function is equal to that of ulcerative colitis patients and better than Crohn's disease patients. Ileal pouch-anal anastomosis should be offered to patients with indeterminate colitis and those with severe colitis in whom clear differentiation between indeterminate colitis and ulcerative colitis cannot be made.     

Reprogramming of primordial germ cells begins before migration into the genital ridge, making these cells inadequate donors for reproductive cloning

Germ cells undergo epigenetic modifications as they develop, which suggests that they may be ideal donors for nuclear transfer (cloning). In this study, nuclei from confirmed embryonic germ cells were used as donors to determine whether they are competent for cloning and at which stage they are most competent. Embryos cloned from migrating 10.5-days-postcoitum (dpc) primordial germ cells (PGCs) showed normal morphological development to midgestation but died shortly thereafter. In contrast, embryos cloned from later-stage germ cells were developmentally delayed at midgestation. Thus, donor germ cell age inversely correlated with the developmental stage attained by cloned embryos. The methylation status of the H19- and Snrpn-imprinting control regions in germ cell clones paralleled that of the donors, and revealed that demethylation, or erasure of imprints, was already initiated in PGCs at 10.5 dpc and was complete by 13.5 dpc. Similarly, clones derived from male 15.5-dpc germ cells showed increased methylation correlating with the initiation of de novo methylation that resets imprints at this stage, and clones from neonatal germ cells showed nearly complete methylation in the H19 imprinting control region. These results indicate that the epigenetic state of the donor nucleus is retained in cloned embryos, and that germ cells are therefore inadequate nuclear donors for cloning because they are either erasing or resetting epigenetic patterns.