RESUMO
Legionella pneumophila is a ubiquitous environmental bacterium that has evolved to infect and proliferate within amoebae and other protists. It is thought that accidental inhalation of contaminated water particles by humans is what has enabled this pathogen to proliferate within alveolar macrophages and cause pneumonia. However, the highly evolved macrophages are equipped with more sophisticated innate defence mechanisms than are protists, such as the evolution of phagotrophic feeding into phagocytosis with more evolved innate defence processes. Not surprisingly, the majority of proteins involved in phagosome biogenesis (~80%) have origins in the phagotrophy stage of evolution. There are a plethora of highly evolved cellular and innate metazoan processes, not represented in protist biology, that are modulated by L. pneumophila, including TLR2 signalling, NF-κB, apoptotic and inflammatory processes, histone modification, caspases, and the NLRC-Naip5 inflammasomes. Importantly, L. pneumophila infects haemocytes of the invertebrate Galleria mellonella, kill G. mellonella larvae, and proliferate in and kill Drosophila adult flies and Caenorhabditis elegans. Although coevolution with protist hosts has provided a substantial blueprint for L. pneumophila to infect macrophages, we discuss the further evolutionary aspects of coevolution of L. pneumophila and its adaptation to modulate various highly evolved innate metazoan processes prior to becoming a human pathogen.
Assuntos
Amoeba/metabolismo , Amoeba/microbiologia , Evasão da Resposta Imune , Imunidade Inata , Legionella pneumophila/fisiologia , Macrófagos/imunologia , Macrófagos/microbiologia , Animais , Caenorhabditis elegans/imunologia , Caenorhabditis elegans/microbiologia , Drosophila/imunologia , Drosophila/microbiologia , Lepidópteros/imunologia , Lepidópteros/microbiologiaRESUMO
Oral supplementation with L-citrulline, which is sequentially converted to L-arginine then nitric oxide, improves vascular biomarkers and reduces blood pressure in non-pregnant, hypertensive human cohorts and pregnant mice with a pre-eclampsia-like syndrome. This early-phase randomised feasibility trial assessed the acceptability of L-citrulline supplementation to pregnant women with chronic hypertension and its effects on maternal BP and other vascular outcomes. Pregnant women with chronic hypertension were randomised at 12-16 weeks to receive 3-g L-citrulline twice daily (n = 24) or placebo (n = 12) for 8 weeks. Pregnant women reported high acceptability of oral L-citrulline. Treatment increased maternal plasma levels of citrulline, arginine and the arginine:asymmetric dimethylarginine ratio, particularly in women reporting good compliance. L-citrulline had no effect on diastolic BP (L-citrulline: - 1.82 95% CI (- 5.86, 2.22) vs placebo: - 5.00 95% CI (- 12.76, 2.76)), uterine artery Doppler or angiogenic biomarkers. Although there was no effect on BP, retrospectively, this study was underpowered to detect BP changes < 9 mmHg, limiting the conclusions about biological effects. The increase in arginine:asymmetric dimethylarginine ratio was less than in non-pregnant populations, which likely reflects altered pharmacokinetics of pregnancy, and further pharmacokinetic assessment of L-citrulline in pregnancy is advised.Trial Registration EudraCT 2015-005792-25 (2017-12-22) and ISRCTN12695929 (2018-09-20).
Assuntos
Citrulina , Hipertensão , Feminino , Humanos , Gravidez , Arginina , Biomarcadores , Suplementos Nutricionais , Óxido Nítrico , Estudos RetrospectivosRESUMO
BACKGROUND: The optimal invasive treatment for sciatica secondary to herniated lumbar disc remains controversial, with a paucity of evidence for use of non-surgical treatments such as transforaminal epidural steroid injection (TFESI) over surgical microdiscectomy. We aimed to investigate the clinical and cost-effectiveness of these options for management of radicular pain secondary to herniated lumbar disc. METHODS: We did a pragmatic, multicentre, phase 3, open-label, randomised controlled trial at 11 spinal units across the UK. Eligible patients were aged 16-65 years, had MRI-confirmed non-emergency sciatica secondary to herniated lumbar disc with symptom duration between 6 weeks and 12 months, and had leg pain that was not responsive to non-invasive management. Participants were randomly assigned (1:1) to receive either TFESI or surgical microdiscectomy by an online randomisation system that was stratified by centre with random permuted blocks. The primary outcome was Oswestry Disability Questionnaire (ODQ) score at 18 weeks. All randomly assigned participants who completed a valid ODQ at baseline and at 18 weeks were included in the analysis. Safety analysis included all treated participants. Cost-effectiveness was estimated from the EuroQol-5D-5L, Hospital Episode Statistics, medication usage, and self-reported resource-use data. This trial was registered with ISRCTN, number ISRCTN04820368, and EudraCT, number 2014-002751-25. FINDINGS: Between March 6, 2015, and Dec 21, 2017, 163 (15%) of 1055 screened patients were enrolled, with 80 participants (49%) randomly assigned to the TFESI group and 83 participants (51%) to the surgery group. At week 18, ODQ scores were 30·02 (SD 24·38) for 63 assessed patients in the TFESI group and 22·30 (19·83) for 61 assessed patients in the surgery group. Mean improvement was 24·52 points (18·89) for the TFESI group and 26·74 points (21·35) for the surgery group, with an estimated treatment difference of -4·25 (95% CI -11·09 to 2·59; p=0·22). There were four serious adverse events in four participants associated with surgery, and none with TFESI. Compared with TFESI, surgery had an incremental cost-effectiveness ratio of £38 737 per quality-adjusted life-year gained, and a 0·17 probability of being cost-effective at a willingness-to-pay threshold of £20 000 per quality-adjusted life-year. INTERPRETATION: For patients with sciatica secondary to herniated lumbar disc, with symptom duration of up to 12 months, TFESI should be considered as a first invasive treatment option. Surgery is unlikely to be a cost-effective alternative to TFESI. FUNDING: Health Technology Assessment programme of the National Institute for Health Research (NIHR), UK.
RESUMO
BACKGROUND: Sciatica is a common condition reported to affect > 3% of the UK population at any time and is most often caused by a prolapsed intervertebral disc. Currently, there is no uniformly adopted treatment strategy. Invasive treatments, such as surgery (i.e. microdiscectomy) and transforaminal epidural steroid injection, are often reserved for failed conservative treatment. OBJECTIVE: To compare the clinical effectiveness and cost-effectiveness of microdiscectomy with transforaminal epidural steroid injection for the management of radicular pain secondary to lumbar prolapsed intervertebral disc for non-emergency presentation of sciatica of < 12 months' duration. INTERVENTIONS: Patients were randomised to either (1) microdiscectomy or (2) transforaminal epidural steroid injection. DESIGN: A pragmatic, multicentre, randomised prospective trial comparing microdiscectomy with transforaminal epidural steroid injection for sciatica due to prolapsed intervertebral disc with < 1 year symptom duration. SETTING: NHS services providing secondary spinal surgical care within the UK. PARTICIPANTS: A total of 163 participants (aged 16-65 years) were recruited from 11 UK NHS outpatient clinics. MAIN OUTCOME MEASURES: The primary outcome was participant-completed Oswestry Disability Questionnaire score at 18 weeks post randomisation. Secondary outcomes were visual analogue scores for leg pain and back pain; modified Roland-Morris score (for sciatica), Core Outcome Measures Index score and participant satisfaction at 12-weekly intervals. Cost-effectiveness and quality of life were assessed using the EuroQol-5 Dimensions, five-level version; Hospital Episode Statistics data; medication usage; and self-reported cost data at 12-weekly intervals. Adverse event data were collected. The economic outcome was incremental cost per quality-adjusted life-year gained from the perspective of the NHS in England. RESULTS: Eighty-three participants were allocated to transforaminal epidural steroid injection and 80 participants were allocated to microdiscectomy, using an online randomisation system. At week 18, Oswestry Disability Questionnaire scores had decreased, relative to baseline, by 26.7 points in the microdiscectomy group and by 24.5 points in the transforaminal epidural steroid injection. The difference between the treatments was not statistically significant (estimated treatment effect -4.25 points, 95% confidence interval -11.09 to 2.59 points). Nor were there significant differences between treatments in any of the secondary outcomes: Oswestry Disability Questionnaire scores, visual analogue scores for leg pain and back pain, modified Roland-Morris score and Core Outcome Measures Index score up to 54 weeks. There were four (3.8%) serious adverse events in the microdiscectomy group, including one nerve palsy (foot drop), and none in the transforaminal epidural steroid injection group. Compared with transforaminal epidural steroid injection, microdiscectomy had an incremental cost-effectiveness ratio of £38,737 per quality-adjusted life-year gained and a probability of 0.17 of being cost-effective at a willingness to pay threshold of £20,000 per quality-adjusted life-year. LIMITATIONS: Primary outcome data was invalid or incomplete for 24% of participants. Sensitivity analyses demonstrated robustness to assumptions made regarding missing data. Eighteen per cent of participants in the transforaminal epidural steroid injection group subsequently received microdiscectomy prior to their primary outcome assessment. CONCLUSIONS: To the best of our knowledge, the NErve Root Block VErsus Surgery trial is the first trial to evaluate the comparative clinical effectiveness and cost-effectiveness of microdiscectomy and transforaminal epidural steroid injection. No statistically significant difference was found between the two treatments for the primary outcome. It is unlikely that microdiscectomy is cost-effective compared with transforaminal epidural steroid injection at a threshold of £20,000 per quality-adjusted life-year for sciatica secondary to prolapsed intervertebral disc. FUTURE WORK: These results will lead to further studies in the streamlining and earlier management of discogenic sciatica. TRIAL REGISTRATION: Current Controlled Trials ISRCTN04820368 and EudraCT 2014-002751-25. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 24. See the NIHR Journals Library website for further project information.
WHAT IS THE PROBLEM?: Sciatica or pain related to nerve irritation travelling down the leg is common in young working adults and most likely to be caused by a 'slipped' (prolapsed) disc. Although the majority of cases get better on their own and within 46 weeks, a significant group of patients struggle with disabling symptoms sometimes beyond 1 year. Consequently, patients struggle to maintain their home and working lives. Many treatments are available for sciatica, but simpler treatments (e.g. pain tablets, physiotherapy and changing one's lifestyle) are often not very effective and patients have often tried all of them by the time they are seen in hospital to have tests, such as scans, done. Surgery to remove part of the disc is recommended in cases where the pain is accompanied by severe weakness in one or both legs, or where doctors think that nerves may be damaged because patients have bladder, bowel and sexual functioning difficulties (i.e. red flag symptoms). Surgery works well in alleviation of referred leg pain and also to relieve pressure on a physically compressed nerve that may be showing clinical sign of injury/weakness. An alternative to surgery is to inject a mixture of anaesthetic and steroid close to the site of the disc injury and nerve, but at the moment we do not know whether or not these injections work in the long term. They are cheaper and less invasive, with fewer risks than surgery, such as from anaesthetic or infection. WHAT DID OUR STUDY INVESTIGATE?: This study compared the usefulness of surgery with injections for patients who have had sciatica for < 1 year and who have tried simple remedies but are still in pain. Patients were allocated to have either surgery or the injection. Symptoms (e.g. pain) were assessed after 18 weeks. WHAT DID WE FIND?: We found that there was no significant difference between surgery and injection at the primary end point. Surgery was not significantly different from injection in terms of clinical outcome and was not cost-effective compared with injection. OUR CONCLUSION AND RECOMMENDATION: Given the cost of surgery and the risks to patients, we suggest that further studies should be carried out to explore whether or not all patients with sciatica due to a slipped disc should be considered suitable for an injection, unless there is a good reason not to.
Assuntos
Disco Intervertebral , Ciática , Análise Custo-Benefício , Humanos , Estudos Prospectivos , Qualidade de Vida , Ciática/tratamento farmacológico , Ciática/etiologia , EsteroidesRESUMO
BACKGROUND: People with advanced dementia who live and die in nursing homes experience variable quality of life, care and dying. There is a need to identify appropriate, cost-effective interventions that facilitate high-quality end-of-life care provision. OBJECTIVES: To establish the feasibility and acceptability to staff and family of conducting a cluster randomised controlled trial of the Namaste Care intervention for people with advanced dementia in nursing homes. DESIGN: The study had three phases: (1) realist review and (2) intervention refinement to inform the design of (3) a feasibility cluster randomised controlled trial with a process evaluation and economic analysis. Clusters (nursing homes) were randomised in a 3 : 1 ratio to intervention or control (usual care). The nature of the intervention meant that blinding was not possible. SETTING: Nursing homes in England providing care for people with dementia. PARTICIPANTS: Residents with advanced dementia (assessed as having a Functional Assessment Staging Test score of 6 or 7), their informal carers and nursing home staff. INTERVENTION: Namaste Care is a complex group intervention that provides structured personalised care in a dedicated space, focusing on enhancements to the physical environment, comfort management and sensory engagement. MAIN OUTCOME MEASURES: The two contender primary outcome measures were Comfort Assessment in Dying - End of Life Care in Dementia for quality of dying (dementia) and Quality of Life in Late Stage Dementia for quality of life. The secondary outcomes were as follows: person with dementia, sleep/activity (actigraphy), neuropsychiatric symptoms, agitation and pain; informal carers, satisfaction with care at the end of life; staff members, person-centred care assessment, satisfaction with care at the end of life and readiness for change; and other data - health economic outcomes, medication/service use and intervention activity. RESULTS: Phase 1 (realist review; 86 papers) identified that a key intervention component was the activities enabling the development of moments of connection. In phase 2, refinement of the intervention enabled the production of a user-friendly 16-page A4 booklet. In phase 3, eight nursing homes were recruited. Two homes withdrew before the intervention commenced; four intervention and two control homes completed the study. Residents with advanced dementia (n = 32) were recruited in intervention (n = 18) and control (n = 14) homes. Informal carers (total, n = 12: intervention, n = 5; control, n = 7) and 97 staff from eight sites (intervention, n = 75; control, n = 22) were recruited over a 6-month period. Recruitment is feasible. Completion rates of the primary outcome questionnaires were high at baseline (100%) and at 4 weeks (96.8%). The Quality of Life in Late Stage Dementia was more responsive to change over 24 weeks. Even where economic data were missing, these could be collected in a full trial. The intervention was acceptable; the dose varied depending on the staffing and physical environment of each care home. Staff and informal carers reported changes for the person with dementia in two ways: increased social engagement and greater calm. No adverse events related to the intervention were reported. CONCLUSIONS: A subsequent definitive trial is feasible if there are amendments to the recruitment process, outcome measure choice and intervention specification. FUTURE WORK: In a full trial, consideration is needed of the appropriate outcome measure that is sensitive to different participant responses, and of clear implementation principles for this person-centred intervention in a nursing home context. TRIAL REGISTRATION: Current Controlled Trials ISRCTN14948133. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 6. See the NIHR Journals Library website for further project information.
Namaste Care is a programme of respectful stimulation for nursing home residents who have advanced dementia. It is person-focused and reflects residents' individual likes and interests. It is claimed that Namaste Care improves quality of life for residents, family and staff, and quality of dying for residents, and can be provided without additional cost. This study explored how feasible it would be to conduct a large study in the future to understand the effects of Namaste Care on people with advanced dementia. Our literature review showed that Namaste Care enables people with advanced dementia to have moments of connection with others. We refined some Namaste Care resources through working with care home staff, family and volunteers to create a user-friendly booklet. Eight care homes were recruited to our 6-month trial; four homes were supported to introduce Namaste Care, two continued as usual and two withdrew. In the four intervention homes, residents with advanced dementia received Namaste Care. Staff used standard measures to assess (1) residents' responses and (2) the economic costs and benefits of Namaste Care. Researchers made observation visits. Records of activity in Namaste Care sessions were completed, and interviews were held with staff and family. Residents wore an ActiGraph (Activinsights Ltd, Kimbolton, UK) device that recorded their levels of sleep and activity. The length and frequency of Namaste Care sessions varied. Nursing homes incurred additional costs but could see ways to reduce those. All residents accepted wearing an ActiGraph device. Staff completed the data collection tools; some measures were more informative than others. Data from interviews showed that most people had positive experiences of Namaste Care. The findings support the view that Namaste Care has benefits for people with advanced dementia in nursing homes. We consider that, with some changes, this trial offers a model for a large study to show whether or not Namaste Care could be promoted more widely.
Assuntos
Demência , Casas de Saúde , Assistência Centrada no Paciente , Qualidade de Vida/psicologia , Assistência Terminal/psicologia , Idoso , Idoso de 80 Anos ou mais , Análise Custo-Benefício , Demência/psicologia , Demência/terapia , Inglaterra , Estudos de Viabilidade , Feminino , Humanos , Masculino , Índice de Gravidade de Doença , Inquéritos e Questionários , Avaliação da Tecnologia BiomédicaRESUMO
The host is a nutrient-rich niche for microbial pathogens, but one that comes with obstacles and challenges. Many intracellular pathogens like Legionella pneumophila, Coxiella burnetii, Listeria monocytogenes, and Chlamydia trachomatis have developed bipartite metabolism within their hosts. This style of metabolic regulation enables pathogen sensing of specific nutrients to engage them into catabolic and anabolic processes, and contributes to temporal and spatial pathogen phenotypic modulation. Not only have intracellular pathogens adapted their metabolism to the host, they have also acquired idiosyncratic strategies to exploit host nutritional supplies and intercept metabolites. Francisella tularensis and Anaplasma phagocytophilum alter host autophagy, Shigella flexneri intercepts all host pyruvate, while L. pneumophila induces host protein degradation and blocks protein translation. Strategies of pathogen manipulation of host nutrients could serve as therapeutic targets.
Assuntos
Metabolismo Energético , Interações Hospedeiro-Patógeno , Fenômenos Fisiológicos da Nutrição , Animais , Humanos , Espaço Intracelular/microbiologia , Legionella/fisiologia , Redes e Vias Metabólicas , VirulênciaRESUMO
Within the human host, Legionella pneumophila replicates within alveolar macrophages, leading to pneumonia. However, L. pneumophila is an aquatic generalist pathogen that replicates within a wide variety of protist hosts, including amoebozoa, percolozoa, and ciliophora. The intracellular lifestyles of L. pneumophila within the two evolutionarily distant hosts macrophages and protists are remarkably similar. Coevolution with numerous protist hosts has shaped plasticity of the genome of L. pneumophila, which harbors numerous proteins encoded by genes acquired from primitive eukaryotic hosts through interkingdom horizontal gene transfer. The Dot/Icm type IVb translocation system translocates â¼6,000 effectors among Legionella species and >320 effector proteins in L. pneumophila into host cells to modulate a plethora of cellular processes to create proliferative niches. Since many of the effectors have likely evolved to modulate cellular processes of primitive eukaryotic hosts, it is not surprising that most of the effectors do not contribute to intracellular growth within human macrophages. Some of the effectors may modulate highly conserved eukaryotic processes, while others may target protist-specific processes that are absent in mammals. The lack of studies to determine the role of the effectors in adaptation of L. pneumophila to various protists has hampered the progress to determine the function of most of these effectors, which are routinely studied in mouse or human macrophages. Since many protists restrict L. pneumophila, utilization of such hosts can also be instrumental in deciphering the mechanisms of failure of L. pneumophila to overcome restriction of certain protist hosts. Here, we review the interaction of L. pneumophila with its permissive and restrictive protist environmental hosts and outline the accomplishments as well as gaps in our knowledge of L. pneumophila-protist host interaction and L. pneumophila's evolution to become a human pathogen.
Assuntos
Coevolução Biológica , Genoma Bacteriano , Interações Hospedeiro-Patógeno/genética , Legionella pneumophila/genética , Amebozoários/microbiologia , Cilióforos/microbiologia , Citoplasma/microbiologia , Humanos , Legionella pneumophila/patogenicidade , Macrófagos/microbiologiaRESUMO
Acquisition of nutrients during intra-vacuolar growth of L. pneumophila within macrophages or amoebae is poorly understood. Since many genes of L. pneumophila are acquired by inter-kingdom horizontal gene transfer from eukaryotic hosts, we examined the presence of human solute carrier (SLC)-like transporters in the L. pneumophila genome using I-TASSER to assess structural alignments. We identified 11 SLC-like putative transporters in L. pneumophila that are structurally similar to SLCs, eight of which are amino acid transporters, and one is a tricarboxylate transporter. The two other transporters, LstA and LstB, are structurally similar to the human glucose transporter, SLC2a1/Glut1. Single mutants of lstA or lstB have decreased ability to import, while the lstA/lstB double mutant is severely defective for uptake of glucose. While lstA or lstB single mutants are not defective in intracellular proliferation within Acanthamoeba polyphaga and human monocyte-derived macrophages, the lstA/lstB double mutant is severely defective in both host cells. The two phenotypic defects of the lstA/lstB double mutant in uptake of glucose and intracellular replication are both restored upon complementation of either lstA or lstB. Our data show that the two glucose transporters, LstA and LstB, are redundant and are required for intracellular replication within human macrophages and amoebae.
Assuntos
Legionella pneumophila/fisiologia , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Acanthamoeba/genética , Acanthamoeba/metabolismo , Animais , Proteínas de Bactérias/genética , Eucariotos/metabolismo , Humanos , Legionella pneumophila/genética , Legionella pneumophila/metabolismo , Macrófagos/metabolismo , Mamíferos/metabolismoRESUMO
Legionella pneumophila invades protozoa with an "accidental" ability to cause pneumonia upon transmission to humans. To support its nutrition during intracellular residence, L. pneumophila relies on host amino acids as the main source of carbon and energy to feed the TCA cycle. Despite the apparent lack of a requirement for glucose for L. pneumophila growth in vitro and intracellularly, the organism contains multiple amylases, which hydrolyze polysaccharides into glucose monomers. Here we describe one predicted putative amylase, LamB, which is uniquely present only in L. pneumophila and L. steigerwaltii among the ~60 species of Legionella. Our data show that LamB has a strong amylase activity, which is abolished upon substitutions of amino acids that are conserved in the catalytic pocket of amylases. Loss of LamB or expression of catalytically-inactive variants of LamB results in a severe growth defect of L. pneumophila in Acanthamoeba polyphaga and human monocytes-derived macrophages. Importantly, the lamB null mutant is severely attenuated in intra-pulmonary proliferation in the mouse model and is defective in dissemination to the liver and spleen. Our data show an essential role for LamB in intracellular replication of L. pneumophila in amoeba and human macrophages and in virulence in vivo.
Assuntos
Amilases/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Legionella pneumophila/metabolismo , Porinas/metabolismo , Receptores Virais/metabolismo , Amoeba , Amilases/fisiologia , Animais , Proteínas da Membrana Bacteriana Externa/fisiologia , Proteínas de Bactérias , Humanos , Legionella , Legionella pneumophila/patogenicidade , Macrófagos/fisiologia , Camundongos , Porinas/fisiologia , Receptores Virais/fisiologia , Virulência , Fatores de VirulênciaRESUMO
FIH-mediated post-translational modification through asparaginyl hydroxylation of eukaryotic proteins impacts regulation of protein-protein interaction. We have identified the FIH recognition motif in 11 Legionella pneumophila translocated effectors, YopM of Yersinia, IpaH4.5 of Shigella and an ankyrin protein of Rickettsia. Mass spectrometry analyses of the AnkB and AnkH effectors of L. pneumophila confirm their asparaginyl hydroxylation. Consistent with localization of the AnkB effector to the Legionella-containing vacuole (LCV) membrane and its modification by FIH, our data show that FIH and its two interacting proteins, Mint3 and MT1-MMP are acquired by the LCV in a Dot/Icm type IV secretion-dependent manner. Chemical inhibition or RNAi-mediated knockdown of FIH promotes LCV-lysosomes fusion, diminishes decoration of the LCV with polyubiquitinated proteins, and abolishes intra-vacuolar replication of L. pneumophila. These data show acquisition of the host FIH by a pathogen-containing vacuole and that asparaginyl-hydroxylation of translocated effectors is indispensable for their function.