Cell-specific roles of GRK2 in onset and severity of hypoxic-ischemic brain damage in neonatal mice

The ubiquitously expressed kinase GRK2 protects against cellular overstimulation by desensitizing G protein-coupled receptors and regulating intracellular signaling. Recently, we described that hypoxia-ischemia (HI)-induced brain damage was accelerated and increased in GRK2^+/? neonatal mice. Using Cre-Lox technology we now investigated the role of decreased GRK2 in only microglia/macrophages or forebrain neurons in development of HI brain injury.Low GRK2 in microglia/macrophages (LysM-GRK2^f/+ mice) was sufficient to accelerate onset of HI damage, without affecting the severity of brain injury at 24 h post-HI as compared to LysM-GRK2^+/+ littermates. Consistently, the ipsilateral hemisphere of GRK2^+/? mice contained microglia with a more rounded phenotype compared to WT mice at 3 h post-HI. Inhibition of microglial/macrophage activity by minocycline treatment prevented the early onset of HI injury in GRK2^+/? mice. In vitro, primary GRK2^+/? microglia stimulated with LPS produced more TNF-α than WT microglia via a p38-dependent pathway. In vivo, HI-induced cerebral p38 activation and TNF-α production were increased in GRK2^+/? mice or in LysM-GRK2^f/+ mice. Our findings indicate that low GRK2 in microglia/macrophages accelerates brain damage via a GRK2/p38/TNF-α-dependent pathway.Reduced GRK2 only in forebrain neurons (CamKIIα-GRK2^f/+ mice) significantly increased severity of HI brain damage without affecting the onset of brain damage.In conclusion, our data indicate that low GRK2 in microglia/macrophages facilitates activation of these cells which may contribute to the earlier onset of cerebral HI injury associated with increased p38 phosphorylation and TNF-α production. The level of GRK2 in neurons is crucial for determining the ultimate severity of HI damage in the newborn brain.     

Prospective Evaluation of the Change of Predialysis Protein‐Bound Uremic Solute Concentration With Postdilution Online Hemodiafiltration

Although protein‐bound uremic compounds have been related to outcome in observational studies, few current dialysis strategies provide more removal of those compounds than standard hemodialysis. We evaluated the evolution of protein‐bound uremic solutes after a switch from high‐flux hemodialysis to postdilution hemodiafiltration (n = 13). We compared predialysis solute concentration at 4, 5, and 9 weeks versus baseline for several protein‐bound compounds and water‐soluble solutes, as well as for β₂‐microglobulin. After 9 weeks of postdilution hemodiafiltration, a significant decrease versus baseline could be detected for total concentration of protein‐bound solutes: p‐cresylsulfate (3.98 ± 1.51–3.17 ± 1.77 mg/dL, ?20%, P < 0.01) and 3‐carboxyl‐4‐methyl‐5‐propyl‐2‐furanpropionic acid (0.72 ± 0.52–0.64 ± 0.46 mg/dL, ?11%, P < 0.01). For the other protein‐bound solutes, hippuric acid, indoleacetic acid, and indoxylsulfate, no change in total concentration could be detected. The concentration of the middle molecule, β₂‐microglobulin, decreased as well after 9 weeks of postdilution hemodiafiltration (24.7 ± 9.3–18.1 ± 6.7 mg/L, ?27%, P < 0.01). For water‐soluble compounds, no significant change of concentration was found. Postdilution hemodiafiltration in comparison to high‐flux hemodialysis provided significant reduction of predialysis concentration of protein‐bound compounds, especially those with the highest protein binding, and of β₂‐microglobulin, by ?11 to ?27% in 9 weeks.     

Apolipoprotein E and LRP1 Increase Early in Parkinson's Disease Pathogenesis

Parkinson's disease (PD) is characterized by α-synuclein-containing Lewy bodies (LBs) and loss of melanized neurons in the substantia nigra (SN). Recently, a link between apolipoprotein E (ApoE) expression, α-synuclein aggregation, and neurodegeneration was suggested. Here, we report on ApoE expression appearing in melanized neurons of the SN and in LBs in both PD and incidental LB disease cases. Interestingly, increased expression of the low-density lipoprotein receptor-related protein 1 (the receptor for ApoE) was also observed in incidental LB disease and PD. Our data suggest that alterations in lipoprotein homeostasis/signaling in melanized neurons of the SN are an early event during PD pathogenesis.     

Double- and monofunctional CD4⁺ and CD8⁺ T-cell responses to Mycobacterium tuberculosis DosR antigens and peptides in long-term latently infected individuals

More than 2 billion individuals are latently infected with Mycobacterium tuberculosis (Mtb). Knowledge of the key Mtb antigens and responding T-cell subsets mediating protection against Mtb is critical for developing improved tuberculosis (TB) vaccines. We previously reported that Mtb DosR-regulon-encoded antigens are recognized well by human T cells in association with control of Mtb infection. The characteristics of the responding T-cell subsets, however, remained unidentified. We have therefore studied the cytokine production and memory phenotypes of Mtb DosR-regulon-encoded antigen-specific T cells from individuals who had been infected with Mtb decades ago, yet never developed TB (long-term latent Mtb-infected individuals). Using multi-parameter flow cytometry and intracellular cytokine staining for IFN-γ, TNF-α and IL-2, we found double and single cytokine-producing CD4(+) as well as CD8(+) T cells to be the most prominent subsets, particularly IFN-γ(+) TNF-α(+) CD8(+) T cells. The majority of these T cells comprised effector memory and effector T cells. Furthermore, CFSE labeling revealed strong CD4(+) and CD8(+) T-cell proliferative responses induced by several "immunodominant" Mtb DosR antigens and their specific peptide epitopes. These findings demonstrate the prominent presence of double- and monofunctional CD4(+) and CD8(+) T-cell responses in naturally protected individuals and support the possibility of designing Mtb DosR antigen-based TB vaccines.     

Spinal anesthesia for intrapartum Cesarean delivery following epidural labor analgesia: a retrospective cohort study

Purpose

Failed conversion of epidural labor analgesia (ELA) to epidural surgical anesthesia (ESA) for intrapartum Cesarean delivery (CD) has been observed in clinical practice. However, spinal anesthesia (SA) in parturients experiencing failed conversion of ELA to ESA has been associated with an increased incidence of serious side effects. In this retrospective cohort analysis, we examined our routine clinical practice of removing the in situ epidural, rather than attempting to convert to ESA, prior to administering SA for intrapartum CD.

Methods

Hemodynamic data, frequencies of either high or total spinal block, and maternal and neonatal outcome data were gathered from the anesthesia records of all parturients at the Amphia Hospital, undergoing intrapartum CD between January 1, 2001 and May 1, 2005.

Results

Complete data were available for 693 patients (97.6%) of the 710 medical records that were identified. Of the 693 patients, 508 (73.3%) had no ELA and received SA, 128 patients (18.5%) received SA following epidural anesthesia for labor, 19 (2.7%) underwent conversion of ELA to ESA, and 38 (5.5%) received general anesthesia. When comparing both SA groups, no clinically relevant differences were observed regarding the incidence of total spinal block (0% in both groups) or high spinal block (0.2 vs 0.8%, P = 0.36). The number of hypotensive episodes, the total amount of ephedrine administered, and the Apgar scores recorded at 5 and 10 min were similar amongst groups.

Conclusions

The incidence of serious side effects associated with SA for intrapartum CD following ELA is low and not different compared to SA only.     

Deployment-related severe fatigue with depressive symptoms is associated with increased glucocorticoid binding to peripheral blood mononuclear cells

Severe fatigue and co-morbid depressive symptoms are frequently reported by recently deployed military personnel. Stress can induce lasting changes in the negative feedback regulation of the hypothalamic–pituitary–adrenal axis (HPA-axis) and the regulation of the immune system by cortisol. Since these actions of cortisol are modulated via glucocorticoid receptors (GR), we investigated the effect of deployment and of deployment-related fatigue on glucocorticoid binding to peripheral blood mononuclear cells (PBMCs) in a prospective design. Psychological assessments and blood sample collection took place before and one and six months after deployment. Participants were selected from a larger group and assigned to three groups based on their level of fatigue and depressive symptoms six months after deployment. We compared fatigued participants without depressive symptoms (n = 21), fatigued participants with depressive symptoms (n = 14) and non-fatigued participants without depressive symptoms (n = 21). Fatigued participants with depressive symptoms at six months after deployment had higher glucocorticoid binding to PMBCs than the other two groups at all three time points. Notably, this difference was already present before deployment. There was no effect of deployment on glucocorticoid binding to PBMCs. The observed differences in glucocorticoid binding were not related to pre-existing group differences in psychological symptoms. No group differences were observed in the composition of the PBMC population and plasma cortisol levels. These results indicate that high glucocorticoid binding to PBMCs might represent a vulnerability factor for the development of severe fatigue with depressive symptoms after a sustained period of stress, such as deployment.     

First-year quality of life assessment of an intra-arterial (RADPLAT) versus intravenous chemoradiation phase III trial

Background.

We report the results of a multicenter randomized phase III study, assessing quality of life (QOL) in intra‐arterial (IA) versus standard intravenous (IV) chemoradiation in advanced head and neck cancer.

Methods.

Two hundred seven patients with inoperable stage IV disease—152 men and 55 women; mean age, 55 years—were included in this study. The patients were treated with standard radiotherapy with 4 weekly IA or 3 weekly IV cisplatin infusions. The QOL assessments carried out were EORTC‐C30, H&N35, and trial‐specific questionnaires.

Results.

Overall QOL deteriorated in all patients during treatment, is gradually improving over 1 year. IA patients showed significantly less nausea and vomiting at week 7 (p <.001). IV patients were significantly more fatigued (p <.006). At 1 year, no significant difference in tube feeding was found. Voice quality slightly exceeded the pretreatment values at 1 year. Forty‐two of 62 employed patients returned to work.

Conclusion.

During treatment, significantly fewer problems with nausea and vomiting occurred in IA than in IV patients. Both groups showed improved voicing and oral intake during follow‐up, often exceeding pretreatment values at 1 year. © 2008 Wiley Periodicals, Inc. Head Neck, 2009