A Large Randomized Trial: Effects of Mindfulness-Based Stress Reduction (MBSR) for Breast Cancer (BC) Survivors on Salivary Cortisol and IL-6.

Breast cancer survivors (BCS) often experience psychological and physiological symptoms after cancer treatment. Mindfulness-based stress reduction (MBSR), a complementary and alternative therapy, has reduced subjective measures of stress, anxiety, and fatigue among BCS. Little is known, however, about how MBSR affects objective markers of stress, specifically the stress hormone cortisol and the pro-inflammatory cytokine interleukin-6 (IL-6). In the present study, BCS ( N = 322) were randomly assigned to a 6-week MBSR program for BC or usual-care control. Measurements of cortisol, IL-6, symptoms, and quality of life were obtained at orientation and 6 weeks. Cortisol and IL-6 were also measured prior to and after the MBSR(BC) class Weeks 1 and 6. The mean age of participants was 56.6 years and 69.4% were White non-Hispanic. Most had Stage I (33.8%) or II (35.7%) BC, and 35.7% had received chemotherapy and radiation. Cortisol levels were reduced immediately following MBSR(BC) class compared to before the class Weeks 1 and 6 (Wilcoxon-signed rank test; p < .01, d = .52-.56). IL-6 was significantly reduced from pre- to postclass at Week 6 (Wilcoxon-signed rank test; p < .01, d = .21). No differences were observed between the MBSR(BC) and control groups from baseline to Week 6 using linear mixed models. Significant relationships with small effect sizes were observed between IL-6 and both symptoms and quality of life in both groups. Results support the use of MBSR(BC) to reduce salivary cortisol and IL-6 levels in the short term in BCS.

Comparison of Hair Cortisol Levels and Perceived Stress in Mothers Who Deliver at Preterm and Term.

OBJECTIVE: To evaluate relationships between hair cortisol levels and perceived stress in mothers who deliver preterm and term. We hypothesized that the rate of change in cortisol levels would be greater in the preterm delivery group. METHODS: This preliminary study compared hair cortisol levels and Perceived Stress Scale (PSS) scores in predominately Caucasian mothers who delivered preterm ( n = 22) and term ( n = 30). We collected PSS and hair samples of ≥10 cm in length from mothers after delivery. Hair was segmented into three sections, and cortisol was measured using enzyme-linked immunosorbent assay. RESULTS: The mean gestational age was 31.45 ( SD = 4.2) weeks for preterm deliveries and 39.45 ( SD = 1.1) for term. Cortisol differed significantly in the third trimester between mothers delivering term and preterm ( t = 2.16, df = 48, p = .04) and trended toward significance in the second trimester ( t = 1.88, df = 48, p = .06). PSS differed significantly between the two groups ( t = -2.96, df = 50, p = .05). Our data did not provide support for our hypothesis. CONCLUSION: There appeared to be a blunted, flattened pattern of change in cortisol levels across gestation in the women who delivered preterm, suggesting diminished hypothalamic-pituitary-adrenal axis responsiveness in mechanisms that promote preterm labor. Future studies are needed to further evaluate best strategies for measuring the mechanisms of allostatic load during pregnancy along with the psychoneuroendocrine and immune triggers and placental responses that lead to premature birth.

Evaluation of Viral Surrogate Markers for Study of Pathogen Dissemination During Simulations of Patient Care.

During patient care simulations, cauliflower mosaic virus DNA and bacteriophage MS2 performed similarly as surrogate markers of pathogen dissemination. These markers disseminated to the environment in a manner similar to Clostridium difficile spores but were more frequently detected on skin and clothing of personnel after personal protective equipment removal.

A Systematic Review: The Utility of the Revised Version of the Score for Neonatal Acute Physiology Among Critically Ill Neonates.

The revised version of the Score for Neonatal Acute Physiology (SNAP-II) has been used across all birth weights and gestational ages to measure the concept of severity of illness in critically ill neonates. The SNAP-II has been operationalized in various ways across research studies. This systematic review seeks to synthesize the available research regarding the utility of this instrument, specifically on the utility of measuring severity of illness sequentially and at later time points. A systematic review was performed and identified 35 research articles that met inclusion and exclusion criteria. The majority of the studies used the SNAP-II instrument as a measure of initial severity of illness on the first day of life. Six studies utilized the SNAP-II instrument to measure severity of illness at later time points and only 2 studies utilized the instrument to prospectively measure severity of illness. Evidence to support the use of the SNAP-II at later time points and prospectively is lacking and more evidence is needed.

Relationships among prenatal depression, plasma cortisol, and inflammatory cytokines.

A secondary pilot study was carried out as part of a larger parent study of thyroid function in pregnancy and postpartum. All women in the parent study (N = 631) had blood samples, demographic data, and measures of perceived stress and dysphoric moods collected between 16 and 26 weeks' gestation. The current study was completed with a subset of 105 pregnant women to examine the relationships among perceived stress, depression, plasma cortisol, and cytokines during the second trimester of pregnancy. Stress was measured using Cohen's Perceived Stress Scale and dysphoric moods using the Profile of Mood States Depression/Dejection Scale. Cytokines were measured by a 12-plex analysis on a Luminex-200, and cortisol was measured by enzyme-linked immunosorbent assay on stored plasma samples. Stress and depression scores were highly correlated, and depressive symptoms were inversely correlated with 3 of the 12 cytokines: interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and IL-7. Cortisol was inversely correlated with proinflammatory cytokines (IL-1ß and TNF-α) and anti-inflammatory cytokines (IL-4, IL-5, IL-10, and IL-13). These data support the new conceptualizations of normal pregnancy as an inflammatory state that is carefully regulated, as both excessive and inadequate inflammation are potentially hazardous to the health of the pregnancy and fetus.

Trends in Cervical Cancer Among Delivery-Related Discharges and its Impact on Maternal-Infant Birth Outcomes (United States, 1998-2009).

OBJECTIVES: To estimate the national prevalence of cervical cancer (CCA) in women discharged from hospital after delivery, and to examine its associations with birth outcomes. METHODS: We did a retrospective cross-sectional analysis of maternal hospital discharges in the United States (1998-2009). We used the Nationwide Inpatient Sample (NIS) database to identify hospital stays for women who gave birth. We determined length of hospital stay, in-hospital mortality, and used ICD-9-CM codes to identify CCA and all outcomes of interest. Multivariable logistic regression modeling was used to calculate adjusted odds ratios (AOR) and 95% confidence intervals (CI) for the associations between CCA and feto-maternal outcome. RESULTS: In the 12-year period from 1998 to 2009, there were 8,387 delivery hospitalizations with a CCA diagnosis, a prevalence rate of 1.8 per 100,000 (95% CI=1.6, 1.9). After adjusting for potential confounders, CCA was associated with increased odds of maternal morbidities including: anemia (AOR, 1.78, 95% CI, 1.54-2.06), anxiety (AOR, 1.95, 95% CI, 1.11-3.42), cesarean delivery (AOR, 1.67, 95% CI, 1.46-1.90), and prolonged hospital stay (AOR, 1.51, 95% CI, 1.30-1.76), and preterm birth (AOR, 1.69, 95% CI, 1.46-1.97). CONCLUSION: There is a recent increase in the prevalence of CCA during pregnancy. CCA is associated with severe feto-maternal morbidities. Interventions that promote safer sexual practice and regular screening for CCA should be promoted widely among women of reproductive age to effectively reduce the prevalence of CCA during pregnancy and its impact on the health of mother and baby.

Co-Parenting Relationship Experiences of Black Adolescent Mothers in Active Romantic Partnerships With the Fathers of Their Children.

We conducted an interpretive description of co-parenting relationship experiences of romantically involved Black adolescent mothers and fathers with shared biological children. The study was conducted in Brooklyn, New York, using data from individual in-depth interviews with adolescent mothers and fathers (n = 10). Four themes were identified: (a) putting our heads together; (b) balancing childhood and parenthood; (c) less money, more problems; and (d) if we use condoms, it is for contraception. The co-parenting couples managed very complex relationships, but their mutual interest in the welfare of their children was a relational asset. Co-parents had sparse financial resources but used a moral economy strategy to provide mutual support. Future research is needed that focuses on identifying other co-parent relationship assets and integrating and evaluating their utility for enhancing interventions for adolescent families.

The effects of mindfulness-based stress reduction on objective and subjective sleep parameters in women with breast cancer: a randomized controlled trial.

OBJECTIVE: The purpose of this study was to investigate the effects of mindfulness-based stress reduction for breast cancer survivors (MBSR(BC)) on multiple measures of objective and subjective sleep parameters among breast cancer survivors (BCS). METHODS: Data were collected using a two-armed randomized controlled design among BCS enrolled in either a 6-week MBSR(BC) program or a usual care (UC) group with a 12-week follow-up. The present analysis is a subset of the larger parent trial (ClinicalTrials.gov Identifier: NCT01177124). Seventy-nine BCS participants (mean age 57 years), stages 0-III, were randomly assigned to either the formal (in-class) 6-week MBSR(BC) program or UC. Subjective sleep parameters (SSP) (i.e., sleep diaries and the Pittsburgh Sleep Quality Index (PSQI)) and objective sleep parameters (OSP) (i.e., actigraphy) were measured at baseline, 6 weeks, and 12 weeks after completing the MBSR(BC) or UC program. RESULTS: Results showed indications of a positive effect of MBSR(BC) on OSP at 12 weeks on sleep efficiency (78.2% MBSR(BC) group versus 74.6% UC group, p = 0.04), percent of sleep time (81.0% MBSR(BC) group versus 77.4% UC group, p = 0.02), and less number waking bouts (93.5 in MBSR(BC) group versus 118.6 in the UC group, p < 0.01). Small nonsignificant improvements were found in SSP in the MBSR(BC) group from baseline to 6 weeks (PSQI total score, p = 0.09). No significant relationship was observed between minutes of MBSR(BC) practice and SSP or OSP. CONCLUSIONS: These data suggest that MBSR(BC) may be an efficacious treatment to improve objective and subjective sleep parameters in BCS.

Baseline immune biomarkers as predictors of MBSR(BC) treatment success in off-treatment breast cancer patients.

Researchers focused on patient-centered medicine are increasingly trying to identify baseline factors that predict treatment success. Because the quantity and function of lymphocyte subsets change during stress, we hypothesized that these subsets would serve as stress markers and therefore predict which breast cancer patients would benefit most from mindfulness-based stress reduction (MBSR)-facilitated stress relief. The purpose of this study was to assess whether baseline biomarker levels predicted symptom improvement following an MBSR intervention for breast cancer survivors (MBSR[BC]). This randomized controlled trial involved 41 patients assigned to either an MBSR(BC) intervention group or a no-treatment control group. Biomarkers were assessed at baseline, and symptom change was assessed 6 weeks later. Biomarkers included common lymphocyte subsets in the peripheral blood as well as the ability of T cells to become activated and secrete cytokines in response to stimulation with mitogens. Spearman correlations were used to identify univariate relationships between baseline biomarkers and 6-week improvement of symptoms. Next, backward elimination regression models were used to identify the strongest predictors from the univariate analyses. Multiple baseline biomarkers were significantly positively related to 6-week symptom improvement. The regression models identified B-lymphocytes and interferon-γ as the strongest predictors of gastrointestinal improvement (p < .01), +CD4+CD8 as the strongest predictor of cognitive/psychological (CP) improvement (p = .02), and lymphocytes and interleukin (IL)-4 as the strongest predictors of fatigue improvement (p < .01). These results provide preliminary evidence of the potential to use baseline biomarkers as predictors to identify the patients likely to benefit from this intervention.

Mindfulness based stress reduction (MBSR(BC)) in breast cancer: evaluating fear of recurrence (FOR) as a mediator of psychological and physical symptoms in a randomized control trial (RCT).

To investigate the mechanism(s) of action of mindfulness based stress reduction (MBSR(BC)) including reductions in fear of recurrence and other potential mediators. Eighty-two post-treatment breast cancer survivors (stages 0-III) were randomly assigned to a 6-week MBSR(BC) program (n = 40) or to usual care group (UC) (n = 42). Psychological and physical variables were assessed as potential mediators at baseline and at 6 weeks. MBSR(BC) compared to UC experienced favorable changes for five potential mediators: (1) change in fear of recurrence problems mediated the effect of MBSR(BC) on 6-week change in perceived stress (z = 2.12, p = 0.03) and state anxiety (z = 2.03, p = 0.04); and (2) change in physical functioning mediated the effect of MBSR(BC) on 6-week change in perceived stress (z = 2.27, p = 0.02) and trait anxiety (z = 1.98, p = 0.05). MBSR(BC) reduces fear of recurrence and improves physical functioning which reduces perceived stress and anxiety. Findings support the beneficial effects of MBSR(BC) and provide insight into the possible cognitive mechanism of action.

Lymphocyte recovery after breast cancer treatment and mindfulness-based stress reduction (MBSR) therapy.

OBJECTIVES: This randomized controlled trial was conducted to examine immune recovery following breast cancer (BC) therapy and evaluate the effect of mindfulness-based stress reduction therapy (MBSR) on immune recovery with emphasis on lymphocyte subsets, T cell activation, and production of T-helper 1 (Th1; interferon [IFN]-γ) and T-helper 2 (Th2; interleukin-4 [IL-4]) cytokines. METHOD: Participants who completed the study consisted of 82 patients diagnosed with Stage 0-III BC, who received lumpectomy and adjuvant radiation ± chemotherapy. Patients were randomized into an MBSR(BC) intervention program or a control (usual care) group. Immune cell measures were assessed at baseline and within 2 weeks after the 6-week intervention. The numbers and percentages of lymphocyte subsets, activated T cells, and Th1 and Th2 cells in peripheral blood samples were determined by immunostaining and flow cytometry. RESULTS: Immune subset recovery after cancer treatment showed positive associations with time since treatment completion. The B and natural killer (NK) cells were more susceptible than T cells in being suppressed by cancer treatment. Women who received MBSR(BC) had T cells more readily activated by the mitogen phytohemagglutinin (PHA) and an increase in the Th1/Th2 ratio. Activation was also higher for the MBSR(BC) group if <12 weeks from the end of treatment and women in MBSR(BC) <12 weeks had higher T cell count for CD4(+). CONCLUSION: MBSR(BC) promotes a more rapid recovery of functional T cells capable of being activated by a mitogen with the Th1 phenotype, whereas substantial recovery of B and NK cells after completion of cancer treatment appears to occur independent of stress-reducing interventions.

A pilot study evaluating the effect of mindfulness-based stress reduction on psychological status, physical status, salivary cortisol, and interleukin-6 among advanced-stage cancer patients and their caregivers.

PURPOSE: To investigate whether a mindfulness-based stress reduction program for cancer (MBSR-C) improved psychological and physical symptoms, quality of life (QOL), and stress markers among advanced-stage cancer patients and caregivers. DESIGN: A pilot within-subject design was used. METHOD: Patients previously diagnosed with advanced-stage breast, colon, lung, or prostate cancer and on treatment were recruited from the Moffitt Cancer Center and Research Institute. Twenty-six patient-caregiver dyads completed a modified 6-week, self-study MBSR-C program based on the Kabat-Zinn model. Psychological and physical symptoms and QOL were compared pre- and post-MBSR-C sessions. Salivary cortisol and interleukin-6 were assessed pre- and post-MBSR-C session at 1, 3, and 6 weeks. FINDINGS: Following the 6-week MBSR program, patients showed improvements in stress and anxiety (p < .05); caregivers' psychological and QOL also improved but were not statistically significant. Both patients and caregivers had decreases in cortisol at Weeks 1 and 3 (p < .05) but not at Week 6. Similar to cortisol levels at Week 6, salivary interleukin-6 levels were lower overall (before/after an MBSR-C session), compared with Week 1 for patients and caregivers. CONCLUSIONS: MBSR-C may be a beneficial intervention for reducing stress, anxiety, cortisol levels, and symptoms in advanced-stage cancer patients and may also benefit caregivers.

Mindfulness based stress reduction in post-treatment breast cancer patients: an examination of symptoms and symptom clusters.

To investigate prevalence and severity of symptoms and symptom clustering in breast cancer survivors who attended MBSR(BC). Women were randomly assigned into MBSR(BC) or Usual Care (UC). Eligible women were ≥ 21 years, had been diagnosed with breast cancer and completed treatment within 18 months of enrollment. Symptoms and interference with daily living were measured pre- and post-MBSR(BC) using the M.D. Anderson Symptom Inventory. Symptoms were reported as highly prevalent but severity was low. Fatigue was the most frequently reported and severe symptom among groups. Symptoms clustered into 3 groups and improved in both groups. At baseline, both MBSR(BC) and the control groups showed similar mean symptom severity and interference; however, after the 6-week post-intervention, the MBSR(BC) group showed statistically-significant reduction for fatigue and disturbed sleep (P < 0.01) and improved symptom interference items, compared to the control group. For the between-group comparisons, 11 of 13 symptoms and 5 of 6 interference items had lower means in the MBSR(BC) condition than the control condition. These results suggest that MBSR(BC) modestly decreases fatigue and sleep disturbances, but has a greater effect on the degree to which symptoms interfere with many facets of life. Although these results are preliminary, MBSR intervention post-treatment may effectively reduce fatigue and related interference in QOL of breast cancer survivors.

Feasibility of a mindfulness-based stress reduction program for early-stage breast cancer survivors.

PURPOSE: To assess the feasibility of whether mindfulness-based stress reduction (MBSR) has a positive effect on breast cancer survivors' psychological status, psychosocial characteristics, symptoms, and quality of life (QOL) during the critical transition period from end of treatment to resumption of daily activities. DESIGN: Single-group, quasi-experimental, pretest-posttest design. METHOD: A sample of 19 women who completed breast cancer treatment with lumpectomy, radiation, and/or chemotherapy was recruited from the Moffitt Cancer Center and Research Institute, a National Cancer Institute- designated cancer center, and the University of South Florida. The authors assessed the feasibility, compliance, and whether an 8-week MBSR program positively influenced changes in psychological status (fear of recurrence, perceived stress, anxiety, depression), psychosocial characteristics (optimism, social support, spirituality), physical symptoms, and QOL. FINDINGS: Seventeen women (89.5%) completed the study. The mean age was 57 years; the majority of participants (94%) were White. The estimated compliance rate for the program was 67%. Paired t tests indicated significant improvements fear of recurrence, perceived stress, anxiety, depression, and QOL through MBSR participation. CONCLUSIONS: Participants enrolled in the MBSR classes generally were compliant. Significant improvement in psychological status, symptoms, and QOL can be achieved with MBSR use in this population.

Aberrant expression of LMO4 induces centrosome amplification and mitotic spindle abnormalities in breast cancer cells.

The LIM-only protein, LMO4, is a transcriptional modulator overexpressed in breast cancer. It is oncogenic in murine mammary epithelium and is required for G2/M progression of ErbB2-dependent cells as well as growth and invasion of other breast cancer cell types. However, the mechanisms underlying the oncogenic activity of LMO4 remain unclear. Herein, we show that LMO4 is expressed in all breast cancer subtypes examined and its expression level correlates with the degree of proliferation of such tumours. In addition, we have determined that LMO4 silencing induces G2/M arrest in cells from various breast cancer subtypes, suggesting that LMO4 action in the cell cycle is not restricted to a single breast cancer subtype. This arrest was accompanied by increased cell death, amplification of centrosomes, and formation of abnormal mitotic spindles. Consistent with its ability to positively and negatively regulate the formation of active transcription complexes, overexpression of LMO4 also resulted in an increase in centrosome number. Centrosome amplification has been shown to prolong the G2/M phase of the cell cycle and induce apoptosis; thus, we conclude that supernumerary centrosomes mediate the G2/M arrest and cell death in LMO4-deficient cells. Furthermore, the correlation of centrosome amplification with genomic instability suggests that the impact of dysregulated LMO4 on the centrosome cycle may promote LMO4-induced tumour formation.

Glutaredoxin regulates apoptosis in cardiomyocytes via NFkappaB targets Bcl-2 and Bcl-xL: implications for cardiac aging.

Cardiomyocyte apoptosis is a well-established contributor to irreversible injury following myocardial infarction (MI). Increased cardiomyocyte apoptosis is associated also with aging in animal models, exacerbated by MI; however, mechanisms for this increased sensitivity to oxidative stress are unknown. Protein mixed-disulfide formation with glutathione (protein glutathionylation) is known to change the function of intermediates that regulate apoptosis. Since glutaredoxin (Grx) specifically catalyzes protein deglutathionylation, we examined its status with aging and its influence on regulation of apoptosis. Grx1 content and activity are decreased by approximately 40% in elderly (24-mo) Fischer 344 rat hearts compared to adult (6-mo) controls. A similar extent of Grx1 knockdown in H9c2 cardiomyocytes led to increased apoptosis, decreased NFkappaB-dependent transcriptional activity, and decreased production (mRNA and protein) of anti-apoptotic NFkappaB target genes, Bcl-2 and Bcl-xL. Knockdown of Bcl-2 and/or Bcl-xL in wild-type H9c2 cells to the same extent ( approximately 50%) as observed in Grx1-knockdown cells increased baseline apoptosis; and knockdown of Bcl-xL, but not Bcl-2, also increased oxidant-induced apoptosis analogous to Grx1-knockdown cells. Natural Grx1-deficient cardiomyocytes isolated from elderly rats also displayed diminished NFkappaB activity and Bcl-xL content. Taken together, these data indicate diminution of Grx1 in elderly animals contributes to increased apoptotic susceptibility via regulation of NFkappaB function.

Exercise is associated with elevated proinflammatory cytokines in human milk.

OBJECTIVES: To explore relationships between self-reported exercise in postpartum women and concentrations of cytokines and secretory immunoglobulin A in their milk. METHOD: Fifty-eight frozen, unthawed aliquots of human hindmilk were available for analysis from a previous larger study on the influence of lactation on postpartum stress and immunity. The samples were early-morning, hand-expressed, hindmilk that had been collected between 4 and 6 weeks. Milk cytokines were analyzed by a multiplex assay of 20 cytokines, chemokines, and growth factors. Milk secretory immunoglobulin A was analyzed by enzyme-linked immunosorbent assay. Exercise data were extracted from a demographic questionnaire that was used in the original study and approximate metabolic-equivalent tasks assigned to the exercise levels reported. Based on reported frequency of exercise at a particular metabolic-equivalent task, caloric expenditures were calculated for each mother. RESULTS: With increasing metabolic-equivalent tasks, and thus caloric expenditures, proinflammatory cytokines increased in mothers' milk. Secretory immunoglobulin A concentrations were not affected by mother's exercise. CONCLUSIONS: There are several possible interpretations for these results. These data are preliminary, and a larger, longitudinal study with a more structured exercise instrument will clarify if recommendations should be made about heavy exercise in the early postpartum months.

Randomized controlled trial of mindfulness-based stress reduction (MBSR) for survivors of breast cancer.

OBJECTIVES: Considerable morbidity persists among survivors of breast cancer (BC) including high levels of psychological stress, anxiety, depression, fear of recurrence, and physical symptoms including pain, fatigue, and sleep disturbances, and impaired quality of life. Effective interventions are needed during this difficult transitional period. METHODS: We conducted a randomized controlled trial of 84 female BC survivors (Stages 0-III) recruited from the H. Lee Moffitt Cancer and Research Institute. All subjects were within 18 months of treatment completion with surgery and adjuvant radiation and/or chemotherapy. Subjects were randomly assigned to a 6-week Mindfulness-Based Stress Reduction (MBSR) program designed to self-regulate arousal to stressful circumstances or symptoms (n=41) or to usual care (n=43). Outcome measures compared at 6 weeks by random assignment included validated measures of psychological status (depression, anxiety, perceived stress, fear of recurrence, optimism, social support) and psychological and physical subscales of quality of life (SF-36). RESULTS: Compared with usual care, subjects assigned to MBSR(BC) had significantly lower (two-sided p<0.05) adjusted mean levels of depression (6.3 vs 9.6), anxiety (28.3 vs 33.0), and fear of recurrence (9.3 vs 11.6) at 6 weeks, along with higher energy (53.5 vs 49.2), physical functioning (50.1 vs 47.0), and physical role functioning (49.1 vs 42.8). In stratified analyses, subjects more compliant with MBSR tended to experience greater improvements in measures of energy and physical functioning. CONCLUSIONS: Among BC survivors within 18 months of treatment completion, a 6-week MBSR(BC) program resulted in significant improvements in psychological status and quality of life compared with usual care.

Glutaredoxin regulates autocrine and paracrine proinflammatory responses in retinal glial (muller) cells.

Protein S-glutathionylation is a reversible redox-dependent post-translational modification. Many cellular functions and signal transduction pathways involve proteins whose cysteine-dependent activities are modulated by glutathionylation. Glutaredoxin (Grx1) plays a key role in such regulation because it is a specific and efficient catalyst of deglutathionylation. We recently reported an increase in Grx1 in retinae of diabetic rats and in rat retinal Müller glial cells (rMC-1) cultured in high glucose. This up-regulation of Grx1 was concomitant with NFkappaB activation and induction of intercellular adhesion molecule-1 (ICAM-1). This proinflammatory response was replicated by adenoviral-directed up-regulation of Grx1 in cells in normal glucose. The site of regulation of NFkappaB was localized to the cytoplasm, where IkappaB kinase (IKK) is a master regulator of NFkappaB activation. In the current study, inhibition of IKK activity abrogated the increase in ICAM-1 induced by high glucose or by adenoviral-directed up-regulation of Grx1. Conditioned medium from the Müller cells overexpressing Grx1 was added to fresh cultures of Müller or endothelial cells and elicited increases in the Grx1 and ICAM-1 proteins in these cells. These effects correlate with a novel finding that secretion of interleukin-6 was elevated in the cultures of Grx overexpressing cells. Also, pure interleukin-6 increased Grx1 and ICAM-1 in the rMC-1 cells. Thus, Grx1 appears to play an important role in both autocrine and paracrine proinflammatory responses. Furthermore, IKKbeta isolated from Müller cells in normal glucose medium was found to be glutathionylated on Cys-179. Hence Grx-mediated activation of IKK via deglutathionylation may play a central role in diabetic complications in vivo where Grx1 is increased.

Molecular mechanisms and clinical implications of reversible protein S-glutathionylation.

Sulfhydryl chemistry plays a vital role in normal biology and in defense of cells against oxidants, free radicals, and electrophiles. Modification of critical cysteine residues is an important mechanism of signal transduction, and perturbation of thiol-disulfide homeostasis is an important consequence of many diseases. A prevalent form of cysteine modification is reversible formation of protein mixed disulfides (protein-SSG) with glutathione (GSH). The abundance of GSH in cells and the ready conversion of sulfenic acids and S-nitroso derivatives to S-glutathione mixed disulfides suggests that reversible S-glutathionylation may be a common feature of redox signal transduction and regulation of the activities of redox sensitive thiol-proteins. The glutaredoxin enzyme has served as a focal point and important tool for evolution of this regulatory mechanism, because it is a specific and efficient catalyst of protein-SSG deglutathionylation. However, mechanisms of control of intracellular Grx activity in response to various stimuli are not well understood, and delineation of specific mechanisms and enzyme(s) involved in formation of protein-SSG intermediates requires further attention. A large number of proteins have been identified as potentially regulated by reversible S-glutathionylation, but only a few studies have documented glutathionylation-dependent changes in activity of specific proteins in a physiological context. Oxidative stress is a hallmark of many diseases which may interrupt or divert normal redox signaling and perturb protein-thiol homeostasis. Examples involving changes in S-glutathionylation of specific proteins are discussed in the context of diabetes, cardiovascular and lung diseases, cancer, and neurodegenerative diseases.