Vitamin D3 inhibits proinflammatory cytokines and nitric oxide production by the EOC13 microglial cell line

In recent years, a neuroimmunomodulatory role for 1,25-dihydroxyvitamine D(3) [1,25(OH)(2)D(3)] has emerged. Microglial cells present a potential target for the effects of this hormone in the brain. This study focuses on the effect of 1,25(OH)(2)D(3) on the expression and production of inflammatory cytokines and nitric oxide (NO) by the EOC13 microglial cell line. The presence of the vitamin D3 receptor in microglia was demonstrated by RT-PCR. 1,25(OH)(2)D(3) inhibited the production of tumor necrosis factor-alpha, interleukin-6, and NO by stimulated microglia in a concentration-related fashion. The production of transforming growth factor-beta1 (TGF-beta1), an anti-inflammatory cytokine, was not modified in the presence of 1,25(OH)(2)D(3), indicating that the effects of 1,25(OH)(2)D(3) may not involve TGF-beta1 regulation. These results show that 1,25(OH)(2)D(3) has direct anti-inflammatory properties on microglia. It further supports the hypothesis that 1,25(OH)(2)D(3) could be involved in the maintenance of the brain homeostasis and may have a therapeutic potential in inflammatory pathologies of the central nervous system.     

Investigation of the effect of dietary intake of omega-3 polyunsaturated fatty acids on trauma-induced white matter injury with quantitative diffusion MRI in mice

Previous studies suggest that long-term supplementation and dietary intake of omega-3 polyunsaturated fatty acids (PUFAs) may have neuroprotective effects following brain injury. The objective of this study was to investigate potential neuroprotective effects of omega-3 PUFAs on white matter following closed-head trauma. The closed-head injury model of engineered rotational acceleration (CHIMERA) produces a reproducible injury in the optic tract and brachium of the superior colliculus in mice. Damage is detectable using diffusion tensor imaging (DTI) metrics, particularly fractional anisotropy (FA), with sensitivity comparable to histology. We acquired in vivo (n = 38) and ex vivo (n = 41) DTI data in mice divided into sham and CHIMERA groups with two dietary groups: one deficient in omega-3 PUFAs and one adequate in omega-3 PUFAs. We examined injury effects (reduction in FA) and neuroprotection (FA reduction modulated by diet) in the optic tract and brachium. We verified that diet did not affect FA in sham animals. In injured animals, we found significantly reduced FA in the optic tract and brachium (~10% reduction, p < 0.001), and Bayes factor analysis showed strong evidence to reject the null hypothesis. However, Bayes factor analysis showed substantial evidence to accept the null hypothesis of no diet-related FA differences in injured animals in the in vivo and ex vivo samples. Our results indicate no neuroprotective effect from adequate dietary omega-3 PUFA intake on white matter damage following traumatic brain injury. Since damage from CHIMERA mainly affects white matter, our results do not necessarily contradict previous findings showing omega-3 PUFA-mediated neuroprotection in gray matter.     

Interferon α and Tat involvement in the immunosuppression of uninfected T cells and C-C chemokine decline in AIDS

HIV type 1 (HIV-1) not only directly kills infected CD4⁺ T cells but also induces immunosuppression of uninfected T cells. Two immunosuppressive proteins, interferon α (IFNα) and extracellular Tat, mediate this process because specific antibodies against these proteins prevent generation of suppressor cells in HIV-1-infected peripheral blood mononuclear cell cultures. Furthermore, the production of C-C chemokines in response to immune cell activation, initially enhanced by IFNα and Tat, ultimately is inhibited by these proteins in parallel with their induction of immunosuppression. The clinical corollary is the immunosuppression of uninfected T cells and the decline in C-C chemokine release found at advanced stages of HIV-1 infection paralleling rising levels of IFNα and extracellular Tat. We, therefore, suggest that IFNα and Tat may be critical targets for anti-AIDS strategies.     

Specific overexpression of rheumatoid arthritis–associated HLA–DR alleles and presentation of low‐affinity peptides

Objective

To compare levels of HLA–DR expression in rheumatoid arthritis (RA) patients and healthy controls for whom an ordered expression according to the DR alleles is demonstrated and to test the functional consequences of this expression on peptide presentation.

Methods

Using monoclonal antibodies that recognize different DRB1 alleles, DR molecules were quantitated at the surface of the peripheral blood B cells of 23 RA patients and 17 healthy subjects. The functional consequences of the level of DR surface expression was tested using a universal model of antigen presentation and mutated peptides with variable affinities for the T cell receptor.

Results

In healthy subjects, surface HLA–DR molecules were expressed at different levels according to allele (DR53, DR4, and DR11 less than DR1 less than DR7 less than DR15). In RA patients, this hierarchy was not conserved and, furthermore, the density of RA‐associated DR4 and DR1 molecules was enhanced in patients compared with the basal density in healthy individuals. We demonstrated that an increased expression of DR molecules at the surface of antigen‐presenting cells allowed a noteworthy presentation of low‐affinity peptides that under normal conditions are not efficient in generating a T cell response at physiologic surface density of the DR molecules.

Conclusion

Our results suggest that the specific overexpression of RA‐associated HLA molecules could be responsible for the presentation of low‐affinity autopeptides and therefore the activation of peripheral autoreactive T cells.

     

Transfusion-related leukocytosis in critically ill patients

OBJECTIVE: We observed that many critically ill patients developed leukocytosis following blood transfusions. To validate this observation and to explore a possible mechanism, a prospective study was designed. DESIGN: Prospective, non-interventional study. SETTING: Surgical/medical intensive care unit in a university-affiliated community hospital. PATIENTS: Consecutive patients who required packed red blood cells transfusion. INTERVENTIONS: White blood cell count (mean +/- SD) x 10(9)/L before and 2, 4, 6, 12, and 24 hrs following transfusion of non-filtered packed red cells was measured in 96 patients. MEASUREMENTS AND MAIN RESULTS: Twenty patients were septic at the time of transfusion, whereas 76 were not. The incidence of post-transfusion leukocytosis in septic vs. nonseptic patients was 15% vs. 76%, respectively (p <.001). The white blood cell count in nonseptic patients increased from 14.3 +/- 4.8 before transfusion to 19.5 +/- 7.0 2 hrs following transfusion (p <.001) and returned to baseline in 24 hrs. In the septic group, no significant post-transfusion leukocytosis occurred. In 11 nonseptic patients requiring more than one unit of packed red cells, a significant increase in mean white blood cell count occurred 2 hrs after transfusion with non-filtered packed red cells, whereas transfusion with pre-storage-filtered packed red cells did not result in such an increase. Interleukin-8 concentrations (pg/mL) in stored non-filtered packed red cells were significantly higher after 4 wks of storage (745.5 +/- 710, p =.02) than at weeks 1 (61.2 +/- 21.6) and 2 (59.3 +/- 29). In the last 16 nonseptic patients, the units of non-filtered packed red cells were assayed for interleukin-8 immediately before transfusion. Interleukin-8 concentrations were higher in units that caused leukocytosis in the recipients compared with those that did not (408.4 +/- 202 vs. 65.1 +/- 49, p =.02). CONCLUSIONS: Transfusion of non-filtered packed red cells, but not of pre-storage-filtered packed red cells, may frequently cause an acute and transient leukocytosis in critically ill nonseptic patients. Interleukin-8 accumulating in stored non-filtered packed red cells may play a role in this phenomenon. Recognition of post packed red cell transfusion leukocytosis may avoid unnecessary investigations and therapies in false suspicion of sepsis.     

Measuring quality of life in multiple sclerosis patients with urinary disorders using the Qualiveen questionnaire

OBJECTIVES: To assess the impact of urinary disorders on multiple sclerosis (MS) patients' health-related quality of life and to examine the cross-sectional construct validity of Qualiveen, a questionnaire originally developed for spinal cord injury patients with urinary disorders, in patients with MS. DESIGN: Cohort study. SETTING: Neurourodynamic units in 3 French university hospitals. PARTICIPANTS: Patients with MS (N=197). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: We tested predictions about the relationships among clinical features, the French version of the Multiple Sclerosis Quality of Life questionnaire (SEP-59), the Expanded Disability Status Scale (EDSS), and the 4 domains of the 30-item Qualiveen. RESULTS: Cross-sectional correlations among the 4 Qualiveen domains and type (range, .36-.54), number of symptoms (range, .23-.50), and severity of incontinence (.39-.68) were generally moderate to strong. The SEP-59 bowel and bladder function domain showed moderate to strong relationships with the Qualiveen (range, .39-.59). Relationships with other SEP-59 domains were generally weak (range, .22-.35), and with the EDSS they were very weak. Predictions proved generally accurate (weighted kappa=.61). CONCLUSIONS: Our data supported the Qualiveen's validity as a discriminative instrument for use with patients with MS. Further studies should explore the Qualiveen's longitudinal validity and responsiveness.     

Blood neutrophil functions and cytokine release in severe alcoholic hepatitis: effect of corticosteroids

BACKGROUND/AIMS: Several observations point to an important role of interactions between polymorphonuclear neutrophils and cytokines in severe alcoholic hepatitis. The polymorphonuclear neutrophil activation status and the local and systemic pro- and anti-inflammatory cytokine responses were quantified. The effect of corticosteroids, widely used in this setting, was evaluated using these parameters. METHODS: We studied blood polymorphonuclear neutrophil functions in terms of L-selectin and beta2-integrin expression, H2O2 production and IL-8 and tumor necrosis factor alpha synthesis capacity. We also measured IL-8, tumor necrosis factor alpha and IL-10 plasma and liver tissue levels. Fifteen patients with alcoholic hepatitis were compared to 15 patients with alcoholic cirrhosis without alcoholic hepatitis, and to 10 healthy volunteers. The impact of a 28-day course of corticosteroids on blood neutrophils activation status and cytokine levels was evaluated in patients with alcoholic hepatitis. RESULTS: Blood polymorphonuclear neutrophils were activated, as shown by increased H2O2 production (48+/-6 vs 29+/-6 MFI in healthy controls), and decreased L-selectin expression (300+/-61 vs 449+/-59 in healthy controls). Upon stimulation, polymorphonuclear neutrophils synthesized large amounts of IL-8 (21.7+/-9.2 ng/ml vs 8.8+/-10 ng/ml in healthy controls) and tumor necrosis factor alpha (524+/-132 pg/ml vs 79+/-144 pg/ml in healthy controls). Tumor necrosis factor alpha and IL-8 plasma and tissue levels were markedly increased as IL-10 was barely detectable in alcoholic hepatitis patients, compared to cirrhotic patients and healthy controls. During steroid therapy, plasma levels of the pro-inflammatory cytokine IL-8 fell as early as day 14, while levels of the anti-inflammatory cytokine IL-10 increased on day 21. Finally, polymorphonuclear neutrophil functions returned to normal after treatment. CONCLUSION: Severe alcoholic hepatitis appears to be associated with polymorphonuclear neutrophil activation and an imbalance between pro- and anti-inflammatory cytokines; during steroid therapy a normalization of these parameters was observed.