The role of heat shock protein 70 in mediating age-dependent mortality in sepsis.

Sepsis is primarily a disease of the aged, with increased incidence and mortality occurring in aged hosts. Heat shock protein (HSP) 70 plays an important role in both healthy aging and the stress response to injury. The purpose of this study was to determine the role of HSP70 in mediating mortality and the host inflammatory response in aged septic hosts. Sepsis was induced in both young (6- to 12-wk-old) and aged (16- to 17-mo-old) HSP70(-/-) and wild-type (WT) mice to determine whether HSP70 modulated outcome in an age-dependent fashion. Young HSP70(-/-) and WT mice subjected to cecal ligation and puncture, Pseudomonas aeruginosa pneumonia, or Streptococcus pneumoniae pneumonia had no differences in mortality, suggesting HSP70 does not mediate survival in young septic hosts. In contrast, mortality was higher in aged HSP70(-/-) mice than aged WT mice subjected to cecal ligation and puncture (p = 0.01), suggesting HSP70 mediates mortality in sepsis in an age-dependent fashion. Compared with WT mice, aged septic HSP70(-/-) mice had increased gut epithelial apoptosis and pulmonary inflammation. In addition, HSP70(-/-) mice had increased systemic levels of TNF-α, IL-6, IL-10, and IL-1ß compared with WT mice. These data demonstrate that HSP70 is a key determinant of mortality in aged, but not young hosts in sepsis. HSP70 may play a protective role in an age-dependent response to sepsis by preventing excessive gut apoptosis and both pulmonary and systemic inflammation.

Prevention of lymphocyte apoptosis in septic mice with cancer increases mortality.

Lymphocyte apoptosis is thought to have a major role in the pathophysiology of sepsis. However, there is a disconnect between animal models of sepsis and patients with the disease, because the former use subjects that were healthy prior to the onset of infection while most patients have underlying comorbidities. The purpose of this study was to determine whether lymphocyte apoptosis prevention is effective in preventing mortality in septic mice with preexisting cancer. Mice with lymphocyte Bcl-2 overexpression (Bcl-2-Ig) and wild type (WT) mice were injected with a transplantable pancreatic adenocarcinoma cell line. Three weeks later, after development of palpable tumors, all animals received an intratracheal injection of Pseudomonas aeruginosa. Despite having decreased sepsis-induced T and B lymphocyte apoptosis, Bcl-2-Ig mice had markedly increased mortality compared with WT mice following P. aeruginosa pneumonia (85 versus 44% 7-d mortality; p = 0.004). The worsened survival in Bcl-2-Ig mice was associated with increases in Th1 cytokines TNF-α and IFN-γ in bronchoalveolar lavage fluid and decreased production of the Th2 cytokine IL-10 in stimulated splenocytes. There were no differences in tumor size or pulmonary pathology between Bcl-2-Ig and WT mice. To verify that the mortality difference was not specific to Bcl-2 overexpression, similar experiments were performed in Bim(-/-) mice. Septic Bim(-/-) mice with cancer also had increased mortality compared with septic WT mice with cancer. These data demonstrate that, despite overwhelming evidence that prevention of lymphocyte apoptosis is beneficial in septic hosts without comorbidities, the same strategy worsens survival in mice with cancer that are given pneumonia.

Cancer causes increased mortality and is associated with altered apoptosis in murine sepsis.

OBJECTIVE: Whereas most septic patients have an underlying comorbidity, most animal models of sepsis use mice that were healthy before the onset of infection. Malignancy is the most common comorbidity associated with sepsis. The purpose of this study was to determine whether mice with cancer have a different response to sepsis than healthy animals. DESIGN: Prospective, randomized controlled study. SETTING: Animal laboratory in a university medical center. SUBJECTS: C57Bl/6 mice. INTERVENTIONS: Animals received a subcutaneous injection of either 250,000 cells of the transplantable pancreatic adenocarcinoma cell line Pan02 (cancer) or phosphate-buffered saline (healthy). Three weeks later, mice given Pan02 cells had reproducible, nonmetastatic tumors. Both groups of mice then underwent intratracheal injection of either Pseudomonas aeruginosa (septic) or 0.9% NaCl (sham). Animals were killed 24 hrs postoperatively or followed-up 7 days for survival. MEASUREMENTS AND MAIN RESULTS: Mice with cancer and healthy mice appeared similar when subjected to sham operation, although cancer animals had lower levels of T- and B-lymphocyte apoptosis. Septic mice with cancer had increased mortality compared to previously healthy septic mice subjected to the identical injury (52% vs. 28%; p = .04). This was associated with increased bacteremia but no difference in local pulmonary infection. Septic mice with cancer also had increased intestinal epithelial apoptosis. Although sepsis induced an increase in T- and B-lymphocyte apoptosis in all animals, septic mice with cancer had decreased T- and B-lymphocyte apoptosis compared to previously healthy septic mice. Serum and pulmonary cytokines, lung histology, complete blood counts, and intestinal proliferation were similar between septic mice with cancer and previously healthy septic mice. CONCLUSIONS: When subjected to the same septic insult, mice with cancer have increased mortality compared to previously healthy animals. Decreased systemic bacterial clearance and alterations in intestinal epithelial and lymphocyte apoptosis may help explain this differential response.

Enterocyte-specific epidermal growth factor prevents barrier dysfunction and improves mortality in murine peritonitis.

Systemic administration of epidermal growth factor (EGF) decreases mortality in a murine model of septic peritonitis. Although EGF can have direct healing effects on the intestinal mucosa, it is unknown whether the benefits of systemic EGF in peritonitis are mediated through the intestine. Here, we demonstrate that enterocyte-specific overexpression of EGF is sufficient to prevent intestinal barrier dysfunction and improve survival in peritonitis. Transgenic FVB/N mice that overexpress EGF exclusively in enterocytes (IFABP-EGF) and wild-type (WT) mice were subjected to either sham laparotomy or cecal ligation and puncture (CLP). Intestinal permeability, expression of the tight junction proteins claudins-1, -2, -3, -4, -5, -7, and -8, occludin, and zonula occludens-1; villus length; intestinal epithelial proliferation; and epithelial apoptosis were evaluated. A separate cohort of mice was followed for survival. Peritonitis induced a threefold increase in intestinal permeability in WT mice. This was associated with increased claudin-2 expression and a change in subcellular localization. Permeability decreased to basal levels in IFABP-EGF septic mice, and claudin-2 expression and localization were similar to those of sham animals. Claudin-4 expression was decreased following CLP but was not different between WT septic mice and IFABP-EGF septic mice. Peritonitis-induced decreases in villus length and proliferation and increases in apoptosis seen in WT septic mice did not occur in IFABP-EGF septic mice. IFABP-EGF mice had improved 7-day mortality compared with WT septic mice (6% vs. 64%). Since enterocyte-specific overexpression of EGF is sufficient to prevent peritonitis-induced intestinal barrier dysfunction and confers a survival advantage, the protective effects of systemic EGF in septic peritonitis appear to be mediated in an intestine-specific fashion.

Reading Self-Efficacy Predicts Word Reading But Not Comprehension in Both Girls and Boys.

The relationship between cognitive skills and reading has been well-established. However, the role of motivational factors such as self-efficacy in reading progress is less clear. In particular, it is not clear how self-efficacy relates to word level reading versus comprehension, and whether this differs in boys and girls. This study examines the relationship between self-efficacy, word reading and reading comprehension across the range of reading abilities after controlling for reading-related cognitive factors. One hundred and seventy nine children (86 males and 93 females) between 8 and 11 years old completed a self-report measure of reading self-efficacy together with measures of reading comprehension and word reading, working memory, auditory short-term memory, phonological awareness, and vocabulary. Boys and girls showed similar levels of attainment and reading self-efficacy. Reading self-efficacy was associated with word reading, but not with reading comprehension in either boys or girls. It is argued that this may reflect important differences between reading self-efficacy and more general measures of reading motivation and engagement. Reading self-efficacy is an element of reading motivation that is closely associated with a child's perceived attainments in reading and is less susceptible to the gender differences seen in broader measures.

Inhibition of intestinal epithelial apoptosis improves survival in a murine model of radiation combined injury.

World conditions place large populations at risk from ionizing radiation (IR) from detonation of dirty bombs or nuclear devices. In a subgroup of patients, ionizing radiation exposure would be followed by a secondary infection. The effects of radiation combined injury are potentially more lethal than either insult in isolation. The purpose of this study was to determine mechanisms of mortality and possible therapeutic targets in radiation combined injury. Mice were exposed to IR with 2.5 Gray (Gy) followed four days later by intratracheal methicillin-resistant Staphylococcus aureus (MRSA). While either IR or MRSA alone yielded 100% survival, animals with radiation combined injury had 53% survival (p = 0.01). Compared to IR or MRSA alone, mice with radiation combined injury had increased gut apoptosis, local and systemic bacterial burden, decreased splenic CD4 T cells, CD8 T cells, B cells, NK cells, and dendritic cells, and increased BAL and systemic IL-6 and G-CSF. In contrast, radiation combined injury did not alter lymphocyte apoptosis, pulmonary injury, or intestinal proliferation compared to IR or MRSA alone. In light of the synergistic increase in gut apoptosis following radiation combined injury, transgenic mice that overexpress Bcl-2 in their intestine and wild type mice were subjected to IR followed by MRSA. Bcl-2 mice had decreased gut apoptosis and improved survival compared to WT mice (92% vs. 42%; p<0.01). These data demonstrate that radiation combined injury results in significantly higher mortality than could be predicted based upon either IR or MRSA infection alone, and that preventing gut apoptosis may be a potential therapeutic target.

Does BRAF V600E mutation predict aggressive features in papillary thyroid cancer? Results from four endocrine surgery centers.

BACKGROUND: Existing evidence is controversial regarding the association between BRAF mutation status and aggressive features of papillary thyroid cancer (PTC). Specifically, no study has incorporated multiple surgical practices performing routine central lymph node dissection (CLND) and thus has patients who are truly evaluable for the presence or absence of central lymph node metastases (CLNMs). METHODS: Consecutive patients who underwent total thyroidectomy and routine CLND at 4 tertiary endocrine surgery centers were retrospectively reviewed. Descriptive and bivariable analyses examined demographic, patient, and tumor-related factors. Multivariable analyses examined the odds of CLNM associated with positive BRAF status. RESULTS: In patients with classical variant PTC, bivariate analysis found no significant associations between BRAF mutation and aggressive clinicopathologic features; multivariate analysis demonstrated that BRAF status was not an independent predictor of CLNM. When all patients with PTC were analyzed, including those with aggressive or follicular subtypes, bivariate analysis showed BRAF mutation to be associated with LNM, advanced American Joint Committee on Cancer (AJCC) stage, and histologic subtype. Multivariable analyses showed BRAF, age, size, and extrathyroidal extension to be associated with CLNM. CONCLUSION: Although BRAF mutation was found to be an independent predictor of central LNM in the overall cohort of patients with PTC, this relationship lost significance when only classical variant PTC was included in the analysis. The usefulness of BRAF in predicting the presence of LNM remains questionable. Prospective studies are needed before BRAF mutation can be considered a reliable factor to guide the treatment of patients with PTC, specifically whether to perform prophylactic CLND.

Utility of oral nicardipine and magnesium sulfate infusion during preparation and resection of pheochromocytomas.

BACKGROUND: Calcium channel blockade with nicardipine (NC) is an alternative to phenoxybenzamine (PB) preparation for resection of a pheochromocytoma. Intraoperative magnesium sulfate infusion (+MgSO(4)) is often used for its cardiovascular stabilizing properties. We hypothesized that preparation with NC would be similar clinically to PB for resection of a pheochromocytoma, and MgSO(4) infusion would not affect intraoperative stability. METHODS: This retrospective review included 64 patients undergoing resections of a pheochromocytoma from 2003 to 2011. PB or NC was used preoperatively, with MgSO(4) use distributed equally in the population. Pre-, intra-, and postoperative hemodynamics and outcomes were compared. RESULTS: There was no difference in NC (n = 7) versus PB (n = 57) or +MgSO(4) (n = 33) versus -MgSO(4) (n = 31) groups for demographics with the exception of age. The NC group had smaller median tumor size and lesser plasma baseline levels of normetanephrine than the PB group, but subgroup analysis of all neoplasms <3.0 cm revealed no differences. Pre-, intra- and postoperative hemodynamic stability and outcomes were similar for NC versus PB analyses as well as the +MgSO(4) versus -MgSO(4) groups. CONCLUSION: NC use may be an equivalent alternative to PB in preoperative preparation, especially for smaller pheochromocytomas. Intraoperative MgSO(4) use does not seem to have a substantive effect on hemodynamic stability.

The endogenous bacteria alter gut epithelial apoptosis and decrease mortality following Pseudomonas aeruginosa pneumonia.

The endogenous bacteria have been hypothesized to play a significant role in the pathophysiology of critical illness, although their role in sepsis is poorly understood. The purpose of this study was to determine how commensal bacteria alter the host response to sepsis. Conventional and germ-free (GF) C57Bl/6 mice were subjected to Pseudomonas aeruginosa pneumonia. All GF mice died within 2 days, whereas 44% of conventional mice survived for 7 days (P = 0.001). Diluting the dose of bacteria 10-fold in GF mice led to similar survival in GF and conventional mice. When animals with similar mortality were assayed for intestinal integrity, GF mice had lower levels of intestinal epithelial apoptosis but similar levels of proliferation and intestinal permeability. Germ-free mice had significantly lower levels of tumor necrosis factor and interleukin 1ß in bronchoalveolar lavage fluid compared with conventional mice without changes in systemic cytokine production. Under conventional conditions, sepsis unmasks lymphocyte control of intestinal epithelial apoptosis, because sepsis induces a greater increase in gut apoptosis in Rag-1 mice than in wild-type mice. However, in a separate set of experiments, gut apoptosis was similar between septic GF Rag-1 mice and septic GF wild-type mice. These data demonstrate that the endogenous bacteria play a protective role in mediating mortality from pneumonia-induced sepsis, potentially mediated through altered intestinal apoptosis and the local proinflammatory response. In addition, sepsis-induced lymphocyte-dependent increases in gut epithelial apoptosis appear to be mediated by the endogenous bacteria.

Cecal ligation and puncture followed by methicillin-resistant Staphylococcus aureus pneumonia increases mortality in mice and blunts production of local and systemic cytokines.

Mortality in the intensive care unit frequently results from the synergistic effect of two temporally distinct infections. This study examined the pathophysiology of a new model of intra-abdominal sepsis followed by methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Mice underwent cecal ligation and puncture (CLP) or sham laparotomy followed 3 days later by an intratracheal injection of MRSA or saline. Both CLP/saline and sham/MRSA mice had 100% survival, whereas animals with CLP followed by MRSA pneumonia had 67% 7-day survival. Animals subjected to CLP/MRSA had increased bronchoalveolar lavage concentrations of MRSA compared with sham/MRSA animals. Animals subjected to sham/MRSA pneumonia had increased bronchoalveolar lavage levels of interleukin 6 (IL-6), tumor necrosis factor α, and granulocyte colony-stimulating factor compared with those given intratracheal saline, whereas CLP/MRSA mice had a blunted local inflammatory response with markedly decreased cytokine levels. Similarly, animals subjected to CLP/saline had increased peritoneal lavage levels of IL-6 and IL-1ß compared with those subjected to sham laparotomy, whereas this response was blunted in CLP/MRSA mice. Systemic cytokines were upregulated in both CLP/saline and sham/MRSA mice, and this was blunted by the combination of CLP/MRSA. In contrast, no synergistic effect on pneumonia severity, white blood cell count, or lymphocyte apoptosis was identified in CLP/MRSA mice compared with animals with either insult in isolation. These results indicate that a clinically relevant model of CLP followed by MRSA pneumonia causes higher mortality than could have been predicted from studying either infection in isolation, and this was associated with a blunted local (pulmonary and peritoneal) and systemic inflammatory response and decreased ability to clear infection.