Impaired brain glymphatic flow in experimental hepatic encephalopathy

BACKGROUND & AIMS

Neuronal function is exquisitely sensitive to alterations in the extracellular environment. In patients with hepatic encephalopathy (HE), accumulation of metabolic waste products and noxious substances in the interstitial fluid of the brain is thought to result from liver disease and may contribute to neuronal dysfunction and cognitive impairment. This study was designed to test the hypothesis that the accumulation of these substances, such as bile acids, may result from reduced clearance from the brain.

METHODS

In a rat model of chronic liver disease with minimal HE (the bile duct ligation [BDL] model), we used emerging dynamic contrast-enhanced MRI and mass-spectroscopy techniques to assess the efficacy of the glymphatic system, which facilitates clearance of solutes from the brain. Immunofluorescence of aquaporin-4 (AQP4) and behavioural experiments were also performed.

RESULTS

We identified discrete brain regions (olfactory bulb, prefrontal cortex and hippocampus) of altered glymphatic clearance in BDL rats, which aligned with cognitive/behavioural deficits. Reduced AQP4 expression was observed in the olfactory bulb and prefrontal cortex in HE, which could contribute to the pathophysiological mechanisms underlying the impairment in glymphatic function in BDL rats.

CONCLUSIONS

This study provides the first experimental evidence of impaired glymphatic flow in HE, potentially mediated by decreased AQP4 expression in the affected regions.

LAY SUMMARY

The 'glymphatic system' is a newly discovered brain-wide pathway that facilitates clearance of various substances that accumulate in the brain due to its activity. This study evaluated whether the function of this system is altered in a model of brain dysfunction that occurs in cirrhosis. For the first time, we identified that the clearance of substances from the brain in cirrhosis is reduced because this clearance system is defective. This study proposes a new mechanism of brain dysfunction in patients with cirrhosis and provides new targets for therapy.

Guiding practitioners through end of life care for people with dementia: The use of heuristics

Background

End of life care (EOLC) for people with dementia can present a multitude of challenges and difficult decisions for practitioners. These challenges may include assessment and management of difficulties with eating and swallowing, responding to agitation, treating pain, and managing recurrent infections. Practitioners sometimes lack both confidence in making end of life decisions and guidance. This study developed an alternative to lengthy guidelines, in the form of heuristics which were tested in clinical settings. The aim of this study was to test the usability and acceptability of a set of heuristics which could be used by practitioners providing EOLC for people with dementia in a variety of clinical and care settings.

Methods

A three phase co-design process was adopted: 1) Synthesis of evidence and outputs from interviews and focus groups with family carers and practitioners, by a co-design group, to develop heuristics; 2) Testing of the heuristics in five clinical or care settings for six months; 3) Evaluation of the heuristics at three and six months using qualitative individual and group interviews.

Results

Four heuristics were developed covering: eating and swallowing difficulties, agitation and restlessness, reviewing treatment and interventions at the end of life, and providing routine care. The five sites reported that the heuristics were simple and easy to use, comprehensive, and made implicit, tacit knowledge explicit. Four themes emerged from the qualitative evaluation: authority and permission; synthesis of best practice; providing a structure and breaking down complexity; and reassurance and instilling confidence.

Conclusion

Use of heuristics is a novel approach to end of life decision making in dementia which can be useful to both experienced and junior members of staff making decisions. Heuristics are a practical tool which could overcome a lack of care pathways and direct guidance in end of life care for people with dementia.

Evaluation of Response to Stereotactic Radiosurgery in Brain Metastases Using Multiparametric Magnetic Resonance Imaging and a Review of the Literature

AIMS

Following stereotactic radiosurgery (SRS), brain metastases initially increase in size in up to a third of cases, suggesting treatment failure. Current imaging using structural magnetic resonance imaging (MRI) cannot differentiate between tumour recurrence and SRS-induced changes, creating difficulties with patient management. Combining multiparametric MRI techniques, which assess tissue physiological and metabolic information, has shown promise in answering this clinical question.

MATERIALS AND METHODS

Multiparametric MRI techniques, including spectroscopy, diffusion and perfusion imaging, were used for the differentiation of radiation-related changes and tumour recurrence after SRS for intracranial metastases in six cases. All patients presented with enlargement of the treated lesion, an increase in perilesional brain oedema and aggravation or appearance of neurological signs and symptoms from 7 to 29 weeks after primary treatment.

RESULTS

Multiparametric imaging helped to differentiate features of tumour progression (n = 4) from radiation-related changes (n = 2). A low apparent diffusion coefficient (ADC) <1000 × 10^-6 mm²/s, high relative cerebral blood volume (rCBV) ratio > 2.1, high choline:creatine (Cho:Cr) ratio > 1.8 suggested tumour recurrence. A high ADC > 1000 × 10^-6 mm²/s, low rCBV ratio < 2.1, Cho:Cr ratio < 1.8 suggested SRS-induced radiation changes. Multiparametric MRI diagnosis was confirmed by histology or radiological and clinical follow-up.

CONCLUSION

Multiparametric MRI was helpful in the early identification of radiation-related changes and tumour recurrence and may be useful for monitoring treatment changes in intracranial neoplasms after SRS treatment.

Systemic Endotoxin in Peritoneal Dialysis Patients

Previous reports linked systemic endotoxemia in dialysis patients to increased markers of inflammation, cardiovascular disease, and mortality. Many peritoneal dialysis (PD) patients use acidic, hypertonic dialysates, which could potentially increase gut permeability, resulting in systemic endotoxemia. However, the results from studies measuring endotoxin in PD patients are discordant. We therefore measured systemic endotoxin in 55 PD outpatients attending for routine assessment of peritoneal membrane function; mean age 58.7 ± 16.4 years, 32 (58.2%) male, 21 (38.2%) diabetic, median duration of PD treatment 19.5 (13 - 31) months, 32 (58.2%) using 22.7 g/L dextrose dialysates, and 47 (85.5%) icodextrin. The median systemic endotoxin concentration was 0.0485 (0.0043 - 0.103) Eu/mL. We found no association between endotoxin levels and patient demographics, markers of inflammation, serum albumin, N-terminal pro-brain natriuretic peptide, extracellular volume measured by bioimpedance, blood pressure, PD prescriptions or peritoneal membrane transporter status, or medications. The measurement of endotoxin can be lowered by failure to effectively release protein-bound endotoxin prior to analysis and increased by contamination when taking blood samples and processing and storing the samples. Additionally, contamination with β-glucan from fungal cell walls and the use of different assays to analyze endotoxin can also give differing results. These factors may help to explain the disparate results reported in different studies. Our study would suggest that exposure to standard peritoneal dialysates does not substantially increase systemic endotoxin. However, until endotoxin assays can measure free and bound endotoxin separately, the role of endotoxin causing inflammation in PD patients remains to be determined.

"I Want to Feel Like a Full Man": Conceptualizing Gay, Bisexual, and Heterosexual Men's Sexual Difficulties

Current understandings of sexual difficulties originate from a model that is based on the study of heterosexual men and women. Most research has focused on sexual difficulties experienced by heterosexual men incapable of engaging in vaginal penetration. To better understand men's perceptions and experiences of sexual difficulties, seven focus groups and 29 individual interviews were conducted with gay (n = 22), bisexual (n = 5), and heterosexual (n = 25) men. In addition, the extent to which difficulties reported by gay and bisexual men differ from heterosexual men was explored. Data were analyzed using thematic analysis applying an inductive approach. Two intercorrelated conceptualizations were identified: penis function (themes: medicalization, masculine identity, psychological consequences, coping mechanisms) and pain (themes: penile pain, pain during receptive anal sex). For the most part, gay, bisexual, and heterosexual men reported similar sexual difficulties; differences were evident regarding alternative masculinity, penis size competition, and pain during receptive anal sex. The results of this study demonstrate the complexity of men's sexual difficulties and the important role of sociocultural, interpersonal, and psychological factors. Limitations and suggested directions for future research are outlined.

Internet-Based Interventions Aimed at Supporting Family Caregivers of People With Dementia: Systematic Review

Background

Caring for someone with dementia is one of the most challenging caring roles. The need for support for family caregivers has been recognized for some time but is often still lacking. With an aging population, demand on health and social care services is growing, and the population is increasingly looking to the internet for information and support.

Objective

In this review, we aimed to (1) identify the key components of existing internet-based interventions designed to support family caregivers of people with dementia, (2) develop an understanding of which components are most valued by caregivers, and (3) consider the evidence of effectiveness of internet-based interventions designed to support family caregivers of people with dementia.

Methods

We conducted a systematic search of online databases in April 2018. We searched reference lists and tracked citations. All study designs were included. We adopted a narrative synthesis approach with thematic analysis and tabulation as tools.

Results

We identified 2325 studies, of which we included 40. The interventions varied in the number and types of components, duration and dose, and outcomes used to measure effectiveness. The interventions focused on (1) contact with health or social care providers, (2) peer interaction, (3) provision of information, (4) decision support, and (5) psychological support. The overall quality of the studies was low, making interpretation and generalizability of the effectiveness findings difficult. However, most studies suggested that interventions may be beneficial to family caregiver well-being, including positive impacts on depression, anxiety, and burden. Particular benefit came from psychological support provided online, where several small randomized controlled trials suggested improvements in caregiver mental health. Provision of information online was most beneficial when tailored specifically for the individual and used as part of a multicomponent intervention. Peer support provided in online groups was appreciated by most participants and showed positive effects on stress. Finally, online contact with a professional was appreciated by caregivers, who valued easy access to personalized practical advice and emotional support, leading to a reduction in burden and strain.

Conclusions

Although mixed, the results indicate a positive response for the use of internet-based interventions by caregivers. More high-quality studies are required to identify the effectiveness of internet interventions aimed at supporting family caregivers, with particular focus on meeting the needs of caregivers during the different stages of dementia.

Utility and cost evaluation of multiparametric magnetic resonance imaging for the assessment of non-alcoholic fatty liver disease

BACKGROUND

Validated diagnostic tools that are accurate, cost effective and acceptable to patients are required for disease stratification and monitoring in NAFLD.

AIMS

To investigate the performance and cost of multiparametric MRI alongside existing biomarkers in the assessment of NAFLD.

METHODS

Adult patients undergoing standard of care liver biopsy for NAFLD were prospectively recruited at two UK liver centres and underwent multiparametric MRI, blood sampling and transient elastography withing 2 weeks of liver biopsy. Non-invasive markers were compared to histology as the gold standard.

RESULTS

Data were obtained in 50 patients and 6 healthy volunteers. Corrected T1 (cT1) correlated with NAFLD activity score (ρ = 0.514, P < .001). cT1, enhanced liver fibrosis (ELF) test and liver stiffness differentiated patients with simple steatosis and NASH with AUROC (95% CI) of 0.69 (0.50-0.88), 0.87 (0.77-0.79) and 0.82 (0.70-0.94) respectively and healthy volunteers from patients with AUROC (95% CI) of 0.93 (0.86-1.00), 0.81 (0.69-0.92) and 0.89 (0.77-1.00) respectively. For the risk stratification of NAFLD, multiparametric MRI could save £150,218 per 1000 patients compared to biopsy. Multiparametric MRI did not discriminate between individual histological fibrosis stages in this population (P = .068).

CONCLUSIONS

Multiparametric MRI accurately identified patients with steatosis, stratifies those with NASH or simple steatosis and reliably excludes clinically significant liver disease with superior negative predictive value (83.3%) to liver stiffness (42.9%) and ELF (57.1%). For the risk stratification of NAFLD, multiparametric MRI was cost effective and, combined with transient elastography, had the lowest cost per correct diagnosis.

A British Ophthalmological Surveillance Unit Study on metastatic endogenous endophthalmitis

PurposeEndogenous endophthalmitis (EE) is a rare but serious ocular infection caused by the seeding of bacteria into the eye from a source elsewhere in the body. Studies suggest that EE accounts for 2 to 8% of all endophthalmitis.MethodsA prospective observational study was conducted using the British Ophthalmological Surveillance Unit reporting system. Questionnaires were sent to reporting Ophthalmologists in the UK to assess incidence, underlying aetiology, eye findings, management, and final outcomes in endogenous endophthalmitis over a 12-month period within the British Isles.ResultsSixty two cases reported with 48 initial questionnaires returned and 25 6-month follow-up questionnaires returned. The median age of patients affected was 57 years with youngest aged 2 years and oldest aged 85 years. Twenty three were male and 24 were female. The median visual acuity in the affected eye was 3 logMAR (range -0.1 to 5). Blood cultures were taken in 36 patients, 58% of which were positive. Vitreous biopsy was taken in 35 patients, 23% of which were culture positive. The visual function as assessed by visual acuity had significantly improved at 6 months with a median acuity of 0.18 logMAR (P=0.003).ConclusionsThe survey demonstrates the severe nature of endogenous endophthalmitis in patients with active infection or with risk factors for infection. Our study has demonstrated that at least half of the patients who were treated had significant vision improvement.

CSF inflammatory markers and neurocognitive function after addition of maraviroc to monotherapy darunavir/ritonavir in stable HIV patients: the CINAMMON study

CINAMMON is a phase IV, open-label, single-arm, pilot study assessing maraviroc (MVC) in the central nervous system (CNS) when added to darunavir/ritonavir monotherapy (DRV/r) in virologically suppressed HIV-infected subjects. CCR5 tropic participants on DRV/r were recruited. Participants remained on DRV/r for 12 week (w) (control phase). MVC 150 mg qd was added w12-w36 (intervention phase). Lumbar puncture (LP) and neurocognitive function (Cogstate) examinations scheduled at baseline, w12 and w36; MRI before w12, again at w36. Primary endpoint was CSF inflammatory marker changes during intervention phase. Secondary endpoints included changes in NC function and MRI parameters. CSF/plasma DRV/r concentrations measured at w12 and w36, MVC at w36. Nineteen patients recruited, 15 completed (17M, 2F). Dropouts: headache (2), knee problem (could not attend, 1), personal reasons (1). Mean age (range) 45.4 years (27.2-65.1), 13/19 white, 10/19 MSM. No changes in selected CSF markers were seen w12-w36. Overall NC function did not improve w12-w36: total age adjusted z score improved by 0.27 (weighted paired t test; p = 0.11); for executive function only, age adjusted z score improved by 0.54 (p = 0.03). MRI brain parameters unchanged. DRV plasma:CSF concentration ratio unchanged between w12 (132) and w36 (112; p = 0.577, Wilcoxon signed-rank). MVC plasma:CSF concentration ratio was 35 at w36. No changes in neuroinflammatory markers seen. In this small study, addition of 24w MVC 150 mg qd to stable DRV/r monotherapy showed possible improvement in executive function with no global NC effect. Learning effect cannot be excluded. This effect should be further evaluated.

Family caregivers' conceptualisation of quality end-of-life care for people with dementia: A qualitative study

BACKGROUND

People with dementia have been described as the 'disadvantaged dying' with poor end-of-life care. Towards the end of life, people with dementia cannot report on the care they receive. It is therefore important to talk to caregivers; however, few have explored the views about end-of-life care from the caregivers' perspective. The majority of research on family caregivers has focussed on the burden and psychological impact of caring for a relative with dementia.

AIM

This study aimed to explore the views of family caregivers about quality end-of-life care for people with dementia.

DESIGN

Qualitative study using in-depth interviews and analysed using thematic analysis.

SETTING/PARTICIPANTS

Purposive sampling from a third sector organisation's caregiver network was used to recruit 47 caregivers in England (2012-2013), consisting of (1) family caregivers of someone who had recently received a diagnosis of dementia, (2) family caregivers currently caring for someone with dementia and (3) bereaved family caregivers.

RESULTS

Three over-arching themes were derived from the interviewees' discourse, including maintaining the person within, fostering respect and dignity and showing compassion and kindness.

CONCLUSION

End-of-life care for people with dementia does not differ from care throughout the dementia trajectory. Throughout the findings, there is an implicit underlying theme of conflict: conflict between family caregivers and an increasingly systematised service of care and conflict between family caregivers and professionals. This study has in particular demonstrated the importance of the psycho-social aspects of care, aligning with the holistic definition of palliative care.

Hypercoagulability progresses to hypocoagulability during evolution of acetaminophen-induced acute liver injury in pigs

Increases in prothrombin time (PT) and international normalised ratio (INR) characterise acute liver injury (ALI) and failure (ALF), yet a wide heterogeneity in clotting abnormalities exists. This study defines evolution of coagulopathy in 10 pigs with acetaminophen (APAP)-induced ALI compared to 3 Controls. APAP administration began at 0 h and continued to ‘ALF’, defined as INR >3. In APAP pigs, INR was 1.05 ± 0.02 at 0 h, 2.15 ± 0.43 at 16 h and > 3 at 18 ± 1 h. At 12 h thromboelastography (TEG) demonstrated increased clot formation rate, associated with portal vein platelet aggregates and reductions in protein C, protein S, antithrombin and A Disintegrin and Metalloprotease with Thrombospondin type 1 repeats–13 (ADAMTS-13) to 60%, 24%, 47% and 32% normal respectively. At 18 ± 1 h, INR > 3 was associated with: hypocoagulable TEG profile with heparin-like effect; falls in thrombin generation, Factor V and Factor VIII to 52%, 19% and 17% normal respectively; further decline in anticoagulants; thrombocytopenia; neutrophilia and endotoxemia. Multivariate analysis, found that ADAMTS-13 was an independent predictor of a hypercoagulable TEG profile and platelet count, endotoxin, Protein C and fibrinogen were independent predictors of a hypocoagulable TEG profile. INR remained normal in Controls. Dynamic changes in coagulation occur with progression of ALI: a pro-thrombotic state progresses to hypocoagulability.