NK cells suppress experimental cholestatic liver injury by an interleukin-6-mediated, Kupffer cell-dependent mechanism

BACKGROUND & AIMS

Natural killer (NK) cells are innate immune effector cells first characterized by their ability to lyse susceptible tumor cells. Recent studies demonstrated their role in initiating and modulating adaptive immunity. NK cells represent a larger percentage of the lymphoid population in liver than other organs, suggesting that hepatic NK cells express some unique function. Here, we examined the response of NK cells to liver injury that occurs in a mouse model of biliary obstruction.

METHODS

Bile duct ligations (BDL) were performed in mice previously depleted or not depleted of NK cells. NK cell activation, interleukin (IL)-6 mRNA expression and protein production by Kupffer cells, and the ability of exogenous IL-6 to ameliorate liver injury in NK cell-depleted mice, were determined.

RESULTS

The number of activated hepatic NK cells increased markedly following BDL. Activation was suppressed in mice rendered Kupffer cell-depleted prior to ligation. Increased liver injury occurred in NK cell-depleted mice correlating with a reduction in IL-6 production. Purified Kupffer cells, obtained from NK cell-depleted or anti-interferon (IFN)-γ monoclonal antibody-pretreated mice following BDL, produced less IL-6 in culture than did Kupffer cells derived from control animals. In culture, hepatic NK cells derived from BDL mice stimulated IFN-γ-dependent IL-6 production by Kupffer cells; splenic NK cells obtained from the same animals had a negligible effect. Treatment with recombinant murine IL-6 reduced liver injury in BDL, NK cell-depleted mice.

CONCLUSIONS

Hepatic NK cells suppress cholestatic liver injury by stimulating Kupffer cell-dependent IL-6 production.

Detoxified endotoxin vaccine (J5dLPS/OMP) protects mice against lethal respiratory challenge with Francisella tularensis SchuS4

Francisella tularensis is a category A select agent. J5dLPS/OMP is a novel vaccine construct consisting of detoxified, O-polysaccharide side chain-deficient, lipopolysaccharide non-covalently complexed with the outer membrane protein of N. meningitidis group B. Immunization elicits high-titer polyclonal antibodies specific for the highly-conserved epitopes expressed within the glycolipid core that constitutes gram-negative bacteria (e.g., F. tularensis). Mice immunized intranasally with J5dLPS/OMP exhibited protective immunity to intratracheal challenge with the live vaccine strain, as well as the highly-virulent SchuS4 strain, of F. tularensis. The efficacy of J5dLPS/OMP vaccine suggests its potential utility in immunizing the general population against several different gram-negative select agents concurrently.

Effectiveness of Supportive Educative Learning programme on the level of strain experienced by caregivers of stroke patients in Thailand

In Thailand, the crude death rate from stroke is 10.9/100,000 population and increasing. Unlike Western countries where community rehabilitation programmes have been established to provide services following the acute stage of stroke recovery, there is no stroke rehabilitation team in the community in Thailand. Therefore, family caregivers are the primary source for ongoing care and support. While family members accompany patients during their hospitalisation, they receive little information about how to assist their relatives, and as a result feel inadequately trained, poorly informed and dissatisfied with the support that is available after discharge. Family caregivers report that they suffer both physically and psychologically and find themselves overwhelmed with strain, experiencing burden and exhaustion. This study aimed to develop and implement a nurse-led Supportive Educative Learning programme for family caregivers (SELF) of stroke survivors in Thailand and to evaluate the effect of the SELF programme on family caregiver's strain and quality of life. This was a non-randomised comparative study with concurrent controls, using a two-group pre-test and post-test design. A total of 140 stroke survivors and 140 family caregivers were recruited; 70 patients/caregiver pair in each group. Caregivers of patients admitted to the intervention hospital following an acute stroke received the intervention, while caregivers of patients admitted to the comparison hospital received the usual care provided at the hospital. The data were collected prior to discharge of the patients and after 3 months. The family caregivers in the intervention group had a significantly better quality of life than the comparison group (GHQ-28 at discharge t = 2.82, d.f. = 138, P = 0.006; and at 3 months t = 6.80, d.f. = 135, P < 0.001) and they also reported less strain (Caregiver Strain Index at discharge t = 6.73, d.f. = 138, P < 0.001; and at 3 months t = 7.67, d.f. = 135, P < 0.001). This research demonstrated that providing education and support to the family caregiver of stroke survivors can reduce caregiver strain and enhance their quality of life.

Neutrophils sequestered in the liver suppress the proinflammatory response of Kupffer cells to systemic bacterial infection

The liver plays a major role in clearing bacteria from the bloodstream. Rapid clearance is primarily the function of fixed tissue macrophages (Kupffer cells) that line the hepatic sinusoids. Although Kupffer cells play a critical role in blood clearance, the actual elimination of the bulk of bacteria taken up by the liver depends upon the accumulation of bactericidal neutrophils. Subsequent experiments demonstrating neutrophils inside Kupffer cells derived from infected animals prompted our speculation that neutrophils modulate the proinflammatory response of Kupffer cells to bacteria cleared from the bloodstream. Indeed, we report here that neutrophils accumulated in the liver sinusoids suppress cytokine and chemokine mRNA expression and protein production by Kupffer cells. Using listeriosis in mice as an experimental model, we found that IL-1beta, IL-6, IL-10, IL-12, TNF-alpha, MIP-1alpha, keratinocyte-derived chemokine, and MCP-1 mRNA levels were >or=10-fold more in the livers of Listeria-infected, relative to noninfected control, mice at 0.5-2 h after i.v. infection. Most message levels were sharply diminished thereafter, correlating inversely with increased neutrophil sequestration. Relative to intact animals, mice rendered neutrophil deficient exhibited marked increases in cytokine/chemokine mRNA expression and protein production in the liver subsequent to infection. Moreover, purified Kupffer cells derived from infected, neutrophil-depleted mice produced significantly more IL-6, IL-10, IL-12, TNF-alpha, keratinocyte-derived chemokine, and MCP-1 in culture. These findings document the critical role of neutrophils in moderating the proinflammatory response of Kupffer cells to bacteria taken up by the liver.

Epitope-based vaccination against pneumonic tularemia

Francisella tularensis, the etiological agent of tularemia, is one of the most infectious bacterial pathogens known. No vaccine is currently approved for public use. Previously, we identified epitopes recognized specifically by T cells obtained from individuals following infection with F. tularensis. Here, we report that a subunit vaccine constructed based upon these epitopes elicited protective immunity in "humanized" HLA class II (DRB1*0401) transgenic mice. Vaccinated mice challenged intratracheally with a lethal dose of F. tularensis (Live Vaccine Strain) exhibited a rapid increase in pro-inflammatory cytokine production and diminished number of organisms in the lungs, and a concurrent increased rate of survival. These results demonstrate the efficacy of an epitope-based tularemia vaccine and suggest that such an approach might be widely applicable to the development of vaccines specific for intracellular bacterial pathogens.

The Ets transcription factor GABP is required for cell-cycle progression

The transition from cellular quiescence (G0) into S phase is regulated by the mitogenic-activation of D-type cyclins and cyclin-dependent kinases (Cdks), the sequestration of the Cdk inhibitors (CDKIs), p21 and p27, and the hyperphosphorylation of Rb with release of E2F transcription factors. However, fibroblasts that lack all D-type cyclins can still undergo serum-induced proliferation and key E2F targets are expressed at stable levels despite cyclical Rb-E2F activity. Here, we show that serum induces expression of the Ets transcription factor, Gabpalpha, and that its ectopic expression induces quiescent cells to re-enter the cell cycle. Genetic disruption of Gabpalpha prevents entry into S phase, and selectively reduces expression of genes that are required for DNA synthesis and degradation of CDKIs, yet does not alter expression of D-type cyclins, Cdks, Rb or E2Fs. Thus, GABP is necessary and sufficient for re-entry into the cell cycle and it regulates a pathway that is distinct from that of D-type cyclins and CDKs.

RKIP sensitizes prostate and breast cancer cells to drug-induced apoptosis

Cancer cells are more susceptible to chemotherapeutic agent-induced apoptosis than their normal counterparts. Although it has been demonstrated that the increased sensitivity results from deregulation of oncoproteins during cancer development (Evan, G. I., and Vousden, K. H. (2001) Nature 411, 342-348; Green, D. R., and Evan, G. I. (2002) Cancer Cell 1, 19-30), little is known about the signaling pathways leading to changes in the apoptotic threshold in cancer cells. Here we show that low RKIP expression levels in tumorigenic human prostate and breast cancer cells are rapidly induced upon chemotherapeutic drug treatment, sensitizing the cells to apoptosis. We show that the maximal RKIP expression correlates perfectly with the onset of apoptosis. In cancer cells resistant to DNA-damaging agents, treatment with the drugs does not up-regulate RKIP expression. However, ectopic expression of RKIP resensitizes DNA-damaging agent-resistant cells to undergo apoptosis. This sensitization can be reversed by up-regulation of survival pathways. Down-regulation of endogenous RKIP by expression of antisense and small interfering RNA (siRNA) confers resistance on sensitive cancer cells to anticancer drug-induced apoptosis. Our studies suggest that RKIP may represent a novel effector of signal transduction pathways leading to apoptosis and a prognostic marker of the pathogenesis of human cancer cells and tumors after treatment with clinically relevant chemotherapeutic drugs.

Neurophysiological assessment of the feasibility and safety of neural tissue transplantation in patients with syringomyelia

The feasibility and safety of a procedure involving fetal spinal cord tissue transplantation in patients with syringomyelia was assessed using a neurophysiological protocol designed to quantitate peripheral nerve function, spinal cord reflex excitability, and spinal cord conduction pathways essential for somatosensory evoked potentials. We report here data obtained before and for 18 months following the transplantation procedure performed on the first two patients in this study. The neurophysiological assessment protocols included measures of cortical and spinal cord evoked potentials, H-reflex excitability, and peripheral nerve conduction. Prior to the procedure, both patients had significant deficits on some of the neurophysiological measures, for example, lower extremity cortical evoked potentials. However, robust measures of intact pathways, such as upper extremity cortical evoked potentials, were also observed preoperatively in both patients. Thus, it was anticipated that conduction in these intact pathways could be at risk either from complications from the transplantation procedure and/or from continued expansion of the syrinx. Following the transplantation procedure, no negative changes were observed in any of the neurophysiological measures in either patient. In addition, patient 1 showed a decrease in the rate potentiation of tibial H-reflexes on the right side and an increase in the response probability of left tibial H-reflexes. The results of this postoperative longitudinal assessment provide a first-level demonstration of the safety of the intraspinal neural tissue transplantation procedure. However, the consideration of safety is currently limited to the grafting procedure itself, since the long-term fates of the donor tissue in these two patients remain to be shown more definitively.

Cellular cholesterol efflux is modulated by phospholipid-derived signaling molecules in familial HDL deficiency/Tangier disease fibroblasts

Familial HDL deficiency (FHD) is the heterozygous form of Tangier disease (TD). Mutations of the ABCA1 gene cause FHD and TD. FHD/TD cells are unable to normally efflux cholesterol onto nascent HDL particles, which are rapidly catabolized. TD fibroblasts have an abnormal pattern of PLC and PLD activation following cell stimulation with HDL(3) or apolipoprotein A-I (apoA-I). We examined cellular cholesterol efflux in FHD and TD fibroblasts by phospholipid-derived-molecules, compared with that of normal cells. We used the PKC agonist 1,2-dioctanoylglycerol (DOG) and phorbol myristate acetate (PMA) to activate PKC, calphostin C, and GO 6976, as inhibitors of PKC; phosphatidic acid (PA), which is the product of PLD, and lysophosphatidic acid (LPA), phosphatidylcholine, sphingomyelin, and beta-cyclodextrin to investigate their potential effect in modulating cellular cholesterol efflux in [(3)H]cholesterol-labeled and cholesterol-loaded fibroblasts. Phosphatidylcholine, sphingomyelin, and beta-cyclodextrin promoted cholesterol efflux in an identical fashion in control, FHD, or TD fibroblasts. In a dose-dependent fashion, DOG (0-200 microM) increased apoA-I-mediated cellular cholesterol efflux by 40% in controls, 71% in FHD, and 242% in TD cells. PMA similarly increased cholesterol efflux to a maximum of 256% in controls, 182% in FHD, and 191% in TD cells. This effect was inhibited by calphostin C. PA (100 microM) also increased cholesterol efflux by 25% in control, 44% in FHD, and 100% in TD cells. Conversely, LPA reduced cholesterol efflux in a dose-dependent fashion in control and FHD cells (-50%, 200 microM) but not in TD cells, where efflux was increased by 140%. Propranolol (100 microM) significantly increased cholesterol efflux at 24 h in all three cell lines. n-Butanol partially decreased the DOG-mediated increase in cholesterol efflux. The inhibitory effect of calphostin C on DOG-stimulated cholesterol efflux could be partially overcome by propranolol, suggesting that PA is a downstream mediator of PKC-stimulated cholesterol efflux. We conclude that PLC and PLD activities are required for apoA-I-mediated cellular cholesterol efflux, and modulating cellular PA concentration can correct, at least partially, the cholesterol efflux defect in FHD and TD.

Decreased cellular cholesterol efflux is a common cause of familial hypoalphalipoproteinemia: role of the ABCA1 gene mutations

BACKGROUND

High density lipoproteins (HDL) are complex lipoprotein particles involved in reverse cholesterol (C) transport and are negatively associated with the risk for coronary artery disease (CAD). We have described a disorder of familial HDL deficiency (FHD) due to abnormal cellular cholesterol efflux. In the present study, we investigated cellular cholesterol efflux on skin fibroblast from 15 probands with moderate to severe hypoalphalipoproteinemia, including one subject with Tangier disease (TD). We performed family studies on eight of these probands (269 individuals) with familial hypoalphalipoproteinemia (defined as a HDL-C <5th%, and with no known cause of HDL deficiency). We have previously shown that four of our FHD patients and patients with TD have mutations at the ABC1 gene, demonstrating that FHD is a heterozygous form of TD.

METHODS

On each subject, we carried out detailed biochemical analysis and determined apoA-I-mediated cellular cholesterol efflux using 3H-cholesterol labeled skin fibroblasts from study subjects compared with controls. TD has also been associated with abnormal cellular cholesterol efflux. Cell fusion experiments with polyethylene glycol (PEG) were carried out with fibroblasts from a subject with TD and one with FHD in order to determine whether the Tangier cells can complement the FHD defect. In all subjects with a reduced cellular cholesterol efflux, exons of the ABCA1 gene were sequenced.

RESULTS

Familial forms of HDL deficiency, defined as HDL-C levels <5th percentile, are a heterogeneous group of lipoprotein disorders. A reduced cellular cholesterol efflux has been identified in eight subjects from seven kindred (7/14 or 50% of probands tested), being reduced by a mean 59% of controls (range 49-63%). In four of these subjects, a mutation at the ABCA1 gene locus was identified. In three other subjects an efflux defect was idenfified but no critical mutation at the ABCA1 gene locus has been identified. In the remaining subjects, (7/14), no efflux defect was identified. Complementation studies reveal that the FHD defect is not corrected by Tangier cells, confirming that FHD and TD represent a spectrum of the same genetic defect.

CONCLUSION

Familial hypoalphalipoproteinemia syndromes are phenotypically heterogeneous; one form is associated with abnormal cellular cholesterol efflux caused by heterozygous mutations at the ABCA1 gene, that defines familial HDL Deficiency while homozygous mutations or compound heterozygocity causes TD. Other forms are primary hypoalphalipoproteinemia of unknown cause, while the remaining cases are associated with hypertriglyceridemia with or without elevated apoB levels. We conclude that a cellular cholesterol defect is a relatively frequent cause of familial HDL deficiency and that a mutation at the ABCA1 gene can be identified in half of these patients.

Mutations in the ABC1 gene in familial HDL deficiency with defective cholesterol efflux

BACKGROUND

A low concentration of HDL cholesterol is the most common lipoprotein abnormality in patients with premature atherosclerosis. We have shown that Tangier disease, a rare and severe form of HDL deficiency characterised by a biochemical defect in cellular cholesterol efflux, is caused by mutations in the ATP-binding-cassette (ABC1) gene. This gene codes for the cholesterol-efflux regulatory protein (CERP). We investigated the presence of mutations in this gene in patients with familial HDL deficiency.

METHODS

Three French-Canadian families and one Dutch family with familial HDL deficiency were studied. Fibroblasts from the proband of each family were defective in cellular cholesterol efflux. Genomic DNA of each proband was used for mutation detection with primers flanking each exon of the ABC1 gene, and for sequencing of the entire coding region of the gene. PCR and restriction-fragment length polymorphism assays specific to each mutation were used to investigate segregation of the mutation in each family, and to test for absence of the mutation in DNA from normal controls.

FINDINGS

A different mutation was detected in ABC1 in each family studied. Each mutation either created a stop codon predicted to result in truncation of CERP, or altered a conserved aminoacid residue. Each mutation segregated with low concentrations of HDL-cholesterol in the family, and was not observed in more than 500 control chromosomes tested.

INTERPRETATION

These data show that mutations in ABC1 are the major cause of familial HDL deficiency associated with defective cholesterol efflux, and that CERP has an essential role in the formation of HDL. Our findings highlight the potential of modulation of ABC1 as a new route for increasing HDL concentrations.

Mutations in ABC1 in Tangier disease and familial high-density lipoprotein deficiency

Genes have a major role in the control of high-density lipoprotein (HDL) cholesterol (HDL-C) levels. Here we have identified two Tangier disease (TD) families, confirmed 9q31 linkage and refined the disease locus to a limited genomic region containing the gene encoding the ATP-binding cassette transporter (ABC1). Familial HDL deficiency (FHA) is a more frequent cause of low HDL levels. On the basis of independent linkage and meiotic recombinants, we localized the FHA locus to the same genomic region as the TD locus. Mutations in ABC1 were detected in both TD and FHA, indicating that TD and FHA are allelic. This indicates that the protein encoded by ABC1 is a key gatekeeper influencing intracellular cholesterol transport, hence we have named it cholesterol efflux regulatory protein (CERP).

Madness and mayhem: the place of people with dementia in a mental health setting

Demographic predictions indicate that there will be between 174,300 and 194,200 people in Australia experiencing dementia of the Alzheimer's type by the year 2006. At present, 60% of those who make up the resident population in nursing homes and aged-care units in psychiatric hospitals suffer from dementia. To explore the place of people with dementia in a mental health setting, a comprehensive review of the literature was undertaken and the results compared with the outcomes of an ethnographic study of a unit for confused older people.

Indications for and outcome of total abdominal hysterectomy for benign disease: a prospective cohort study

OBJECTIVE

To describe the indications for total abdominal hysterectomy for women with nonmalignant disease and to determine the immediate (initial ten days) and medium term outcome.

DESIGN

A prospective cohort study.

SETTING

Three district general hospitals in shire counties, two in outer London and one London teaching hospital.

SUBJECTS

Three hundred and sixty-six women undergoing total abdominal hysterectomy (with or without other procedures) for nonmalignant disease.

INTERVENTIONS

Self-completed patient questionnaires before and ten days, six weeks and three months after surgery. Data extracted from patients' hospital case notes.

MAIN OUTCOME MEASURES

Complications plus change in symptoms, urinary and bowel function, general health status, sexual function, activities of daily living and quality of life.

RESULTS

The principal indications were bleeding, pain or both. Symptoms were severe enough to be socially debilitating and have a major impact on lifestyle. Otherwise, the women were in good health. During the first ten post-operative days the women suffered more pain, urinary discomfort, constipation and a reduction in their ability to perform activities of daily living. Urinary (25%) and wound (25%) infections were the commonest complications. At the same time, significant improvements in psychological health occurred. By six weeks, the principal symptoms had resolved for 95% of the women and early adverse effects on urinary and bowel function had settled. This was reflected in improvements in health status and quality of life including sexual activity. Despite this, these changes did not meet the pre-operative expectations of some women.

CONCLUSIONS

Most women reported substantial benefits from hysterectomy. However, women should be warned about early, transient adverse effects. These findings can serve as a benchmark for nonexperimental evaluations of the effectiveness of new treatment modalities.

Staff in Australian nursing homes: their qualifications, experience and attitudes

This paper is based upon findings from a study carried out by the Institute of Nursing Research between 1989 and 1990. The major objective of the study was to determine the impact of staffing mix on nursing home residents' quality of care and life as measured against the standards set out in 'Living in a Nursing Home'. An additional objective was to identify if there are any factors which may constrain or influence optimality. 'Skills mix' is sometimes used to describe the ratio of different levels of staff in terms of qualifications. The literature suggests, however, that such factors are only one dimension of skills mix in terms of the skills which people bring into their work in nursing homes. Other factors include the numbers of staff; the mix of staff in terms of level of qualification; the life experience of staff; and the educational experience of staff. This paper examines the findings of the study in the light of staff characteristics based on the criteria identified.

Quality of care in nursing homes: from the resident's perspective

This paper derives from a study conducted by the Deakin Institute of Nursing Research between 1988 and 1990, whose major objective was to determine the impact of staffing mix on nursing resident's quality of care and life. Resident satisfaction with life in the nursing home is a key element in determining the quality of care and quality of life provided. Both the literature review and the study objectives supported the view that resident outcome can be collected through assessing the quality of care and the quality of life, through assessment by informed observers using instruments derived from explicitly stated standards, and through eliciting the perceptions of residents themselves. A schedule designed to measure satisfaction with care was developed and resident interviews were undertaken using this measure and the Life Satisfaction Index (A). The majority of responses to the resident satisfaction schedule were positive. The high percentage of positive responses did not correlate with the observations of the research assistants and there was some concern that while residents were able to assess care they were reluctant to criticize the staff or their behaviour.

Skills mix in Australian nursing homes

This study investigated the relationships between skills mix, resident dependency and the quality of care and life of residents in a stratified random sample of 200 non-government homes in four Australian states. The study considered various measures of skills mix including the qualifications of the staff (staffing mix), the exposure of staff to in-service training and the leadership style of the director of nursing. The only relationships found between staffing mix (that is, the proportion of qualified and unqualified staff) related to the positive effect of therapy staff on the variety of experience of residents. Significant relationships between a number of other components of skills mix and the outcomes of care were found. Specifically, exposure to in-service training of staff and the leadership style of the director of nursing affected quality of care. State enrolled nurses were found to be significantly less satisfied with their work than registered nurses or untrained nurse assistants. Further studies are suggested in these areas and a review of skills mix in relation to them is recommended.

Management and leadership in Australian nursing homes

This paper is based on the outcomes of a study undertaken by Deakin Institute of Nursing Research for the Department of Community Services and Health between 1988 and 1990 (1). The study, which looked at the relationship between skills mix and resident outcomes, involved gathering data from 200 nursing homes in four Australian states using questionnaires and a case study approach. One of the major findings related to the importance of the management and leadership style on the outcome of quality of care and life within the nursing home. The pivotal role of the senior nurse (ie the director of nursing or charge nurse) in affecting high quality is consistently reported in the literature and this was confirmed by the study. Factors drawn from the quantitative and qualitative parts of the study, which make an important contribution to the quality of care experienced by residents, included the director of nursing's attitude, commitment and interpersonal skills. Also important were the ideology of the staff, team cohesiveness and positive attitude and an overall staffing environment which adheres to an agreed philosophy and is stable, satisfied and friendly. All of these were found to be influenced by the senior nurse.