Ocular microtremor: a structured review.

Ocular microtremor (OMT) is the smallest of three involuntary fixational micro eye movements, which has led to it being under researched in comparison. The link between OMT and brain function generates a strong rationale for further study as there is potential for its use as a biomarker in populations with neurological injury and disease. This structured review focused on populations previously studied, instrumentation used for measurement, commonly reported OMT outcomes, and recommendations concerning protocol design and future studies. Current methods of quantifying OMT will be reviewed to analyze their efficacy and efficiency and guide potential development and understanding of novel techniques. Electronic databases were systematically searched and compared with predetermined inclusion criteria. 216 articles were identified in the search and screened by two reviewers. 16 articles were included for review. Findings showed that piezoelectric probe is the most common method of measuring OMT, with fewer studies involving non-invasive approaches, such as contact lenses and laser imaging. OMT frequency was seen to be reduced during general anesthesia at loss of consciousness and in neurologically impaired participants when compared to healthy adults. We identified the need for a non-invasive technique for measuring OMT and highlight its potential in clinical applications as an objective biomarker for neurological assessments. We highlight the need for further research on the clinical validation of OMT to establish its potential to identify or predict a meaningful clinical or functional state, specifically, regarding accuracy, precision, and reliability of OMT.

Combination of Clinical and Gait Measures to Classify Fallers and Non-Fallers in Parkinson's Disease.

Although the multifactorial nature of falls in Parkinson's disease (PD) is well described, optimal assessment for the identification of fallers remains unclear. Thus, we aimed to identify clinical and objective gait measures that best discriminate fallers from non-fallers in PD, with suggestions of optimal cutoff scores. METHODS: Individuals with mild-to-moderate PD were classified as fallers (n = 31) or non-fallers (n = 96) based on the previous 12 months' falls. Clinical measures (demographic, motor, cognitive and patient-reported outcomes) were assessed with standard scales/tests, and gait parameters were derived from wearable inertial sensors (Mobility Lab v2); participants walked overground, at a self-selected speed, for 2 min under single and dual-task walking conditions (maximum forward digit span). Receiver operating characteristic curve analysis identified measures (separately and in combination) that best discriminate fallers from non-fallers; we calculated the area under the curve (AUC) and identified optimal cutoff scores (i.e., point closest-to-(0,1) corner). RESULTS: Single gait and clinical measures that best classified fallers were foot strike angle (AUC = 0.728; cutoff = 14.07°) and the Falls Efficacy Scale International (FES-I; AUC = 0.716, cutoff = 25.5), respectively. Combinations of clinical + gait measures had higher AUCs than combinations of clinical-only or gait-only measures. The best performing combination included the FES-I score, New Freezing of Gait Questionnaire score, foot strike angle and trunk transverse range of motion (AUC = 0.85). CONCLUSION: Multiple clinical and gait aspects must be considered for the classification of fallers and non-fallers in PD.

Performance of the SarQoL quality of life tool in a UK population of older people with probable sarcopenia and implications for use in clinical trials: findings from the SarcNet registry.

BACKGROUND: The Sarcopenia Quality of Life (SarQoL) questionnaire is a disease-specific sarcopenia quality of life tool. We aimed to independently assess SarQoL with a particular focus on its suitability as a clinical trial outcome measure. METHODS: We analysed data from the UK Sarcopenia Network and Registry. Measures of physical performance and lean mass were collected at baseline. SarQoL and the Strength, Assistance, Rise, Climb - Falls (SARC-F) questionnaire (to assess functional ability) were collected at both baseline and six-month follow-up. Global changes in fitness and quality of life at 6 months were elicited on seven-point Likert scales. Internal consistency was assessed using Cronbach's alpha. Responsiveness (Cohen's d and Guyatt coefficients) and minimum clinically important differences were calculated for participants reporting slight improvement or worsening in their global scores. Concurrent validity was assessed by correlating baseline SarQoL scores with measures of physical performance and functional ability. RESULTS: We analysed data from 147 participants, 125 of whom underwent follow up assessment; mean age 78 years; 72 (49%) were women. Internal consistency was good; Cronbach's alpha was 0.944 at baseline and 0.732 at telephone follow-up. Correlation between baseline and follow-up SarQoL was weak (r = 0.27; p = 0.03). The minimum clinically important improvement ranged from 5 to 21 points giving trial sample size estimates of 25-100 participants. SarQoL scores were moderately correlated with handgrip (r = 0.37; p < 0.001), SARC-F (r = - 0.45; p < 0.001), short physical performance battery (r = 0.48; p < 0.001) and 4-m walk speed (r = 0.48; p < 0.001). CONCLUSIONS: SarQoL has acceptable performance in older UK participants with probable sarcopenia and is sufficiently responsive for use in clinical trials for sarcopenia.

Visual Cues for Turning in Parkinson's Disease.

Turning is a common impairment of mobility in people with Parkinson's disease (PD), which increases freezing of gait (FoG) episodes and has implications for falls risk. Visual cues have been shown to improve general gait characteristics in PD. However, the effects of visual cues on turning deficits in PD remains unclear. We aimed to (i) compare the response of turning performance while walking (180° and 360° turns) to visual cues in people with PD with and without FoG; and (ii) examine the relationship between FoG severity and response to visual cues during turning. This exploratory interventional study measured turning while walking in 43 participants with PD (22 with self-reported FoG) and 20 controls using an inertial sensor placed at the fifth lumbar vertebrae region. Participants walked straight and performed 180° and 360° turns midway through a 10 m walk, which was done with and without visual cues (starred pattern). The turn duration and velocity response to visual cues were assessed using linear mixed effects models. People with FoG turned slower and longer than people with PD without FoG and controls (group effect: p < 0.001). Visual cues reduced the velocity of turning 180° across all groups and reduced the velocity of turning 360° in people with PD without FoG and controls. FoG severity was not significantly associated with response to visual cues during turning. Findings suggest that visual cueing can modify turning during walking in PD, with response influenced by FoG status and turn amplitude. Slower turning in response to visual cueing may indicate a more cautious and/or attention-driven turning pattern. This study contributes to our understanding of the influence that cues can have on turning performance in PD, particularly in freezers, and will aid in their therapeutic application.

Developing a UK sarcopenia registry: recruitment and baseline characteristics of the SarcNet pilot.

BACKGROUND: sarcopenia registries are a potential method to meet the challenge of recruitment to sarcopenia trials. We tested the feasibility of setting up a UK sarcopenia registry, the feasibility of recruitment methods and sought to characterise the pilot registry population. METHODS: six diverse UK sites took part, with potential participants aged 65 and over approached via mailshots from local primary care practices. Telephone pre-screening using the SARC-F score was followed by in-person screening and baseline visit. Co-morbidities, medications, grip strength, Short Physical Performance Battery, bioimpedance analysis, Geriatric Depression Score, Montreal Cognitive Assessment, Sarcopenia Quality of Life score were performed and permission sought for future recontact. Descriptive statistics for recruitment rates and baseline measures were generated; an embedded randomised trial examined the effect of a University logo on the primary care mailshot on recruitment rates. RESULTS: sixteen practices contributed a total of 3,508 letters. In total, 428 replies were received (12% response rate); 380 underwent telephone pre-screening of whom 215 (57%) were eligible to attend a screening visit; 150 participants were recruited (40% of those pre-screened) with 147 contributing baseline data. No significant difference was seen in response rates between mailshots with and without the logo (between-group difference 1.1% [95% confidence interval -1.0% to 3.4%], P = 0.31). The mean age of enrollees was 78 years; 72 (49%) were women. In total, 138/147 (94%) had probable sarcopenia on European Working Group on Sarcopenia 2019 criteria and 145/147 (98%) agreed to be recontacted about future studies. CONCLUSION: recruitment to a multisite UK sarcopenia registry is feasible, with high levels of consent for recontact.

200 Years of Parkinson's disease: what have we learnt from James Parkinson?

2017 marks 200 years since James Parkinson's published his 'Essay on the Shaking Palsy'. Although now most famous for describing the condition that came to bear his name, Parkinson had a wide range of interests and his influence spread beyond medicine. In this review, we provide a biography of James Parkinson's remarkable life.Parkinson's paper not only comprehensively described the symptoms of Parkinson's disease (PD), but challenged his peers to better understand the pathophysiology of the PD. Key observation over the next 2 centuries, included the recognition of the link between the substantia nigra and PD and the discoveries of dopamine deficiency in patients with PD. We review the subsequent development of pharmacological and surgical therapies. Despite great progress over the last 200 years, Parkinson's hopes for a 'cure if employed early enough' or that 'some remedial process may ere long be discovered by which at least the progression of the disease may be stopped' remain apposite today and we reflect on the challenges ahead for the next century.

A prospective study of the association between orthostatic hypotension and falls: definition matters.

Background: falls are a common cause of morbidity and mortality in older people. Orthostatic hypotension (OH) is considered an important risk factor for falls, but longitudinal studies have failed to show a clear association. This disparity may be because conventional methods of measuring blood pressure (BP) changes are too imprecise and/or the diagnostic criteria for OH are inappropriate. Over recent years, beat-to-beat BP monitoring techniques, which enabled accurate measurement of vasodepression, have become widely used and in 2011 the American Academy of Neurology produced revised diagnostic criteria for OH. Objective: to use beat-to-beat monitoring to compare the prevalence of OH using the standard and revised diagnostic criteria and to establish which criteria are most valuable in predicting future falls. Design: two hundred and ninety-seven community-dwelling older people aged ≥65 years underwent assessment. Active stand using digital photoplethysmography was used to record postural change in BP. One hundred participants were asked to complete prospective weekly falls diaries for 12 months. Results: OH, defined according to the revised American Academy of Neurology diagnostic criteria, affected 25% of participants and was an independent predictor of falls (odds ratio 10.299, 95% confidence interval [95% CI]: 1.703-61.43, P = 0.011) and time to first fall (hazard ratio 3.017, 95% CI: 1.291-7.050, P = 0.011). OH, defined according to standard criteria, affected 80% of the population and was not associated with falls. Conclusion: OH, defined according to 2011 criteria, is associated with falls and time to first fall. These findings indicate that beat-to-beat monitoring and the 2011 criteria for OH are valuable in the clinical assessment of older fallers.

Orthostatic hypotension and cognitive impairment in Parkinson's disease: Causation or association?

Orthostatic hypotension and cognitive impairment are common in Parkinson's disease (PD) and significantly impair quality of life. Orthostatic hypotension and cognitive impairment appear to be interrelated. Whether the relationship is causative or associative remains unclear. The vascular hypothesis proposes that recurrent episodic hypotension results in cerebral hypoperfusion, in turn causing anoxic damage to vulnerable areas of the brain and impaired cognitive function. Support for this hypothesis has come from brain MRI studies showing an association between white matter hyperintensities and a postural drop in blood pressure among PD patients. Alternatively, the association between orthostatic hypotension and cognitive decline in PD may reflect shared underlying synuclein-related pathology affecting common neuroanatomical and neurochemical substrates. Cardiac imaging studies demonstrate noradrenergic denervation early in PD, and cardiac denervation has been associated with poorer cognition. Neurogenic orthostatic hypotension occurs as a result of defective norepinephrine release from sympathetic terminals upon standing. Neuropathological studies have also demonstrated Lewy body pathology in the locus coeruleus; the main source of noradrenaline in the brain. Locus coeruleus norepinephrine levels are reduced in PD patients with dementia when compared with PD patients without. In this review, we examine the evidence for an association between orthostatic hypotension and cognitive impairment in PD. We evaluate the literature supporting the hypothesis that progressive noradrenergic denervation underlies both orthostatic hypotension and cognitive impairment, and we examine studies suggesting that recurrent cerebral hypoperfusion results in cognitive decline in PD. Finally, we explore how modulation of blood pressure and the noradrenergic nervous system may improve cognition in PD. © 2016 International Parkinson and Movement Disorder Society.

Inhibiting TLR2 activation attenuates amyloid accumulation and glial activation in a mouse model of Alzheimer's disease.

The effects of Toll-like receptor (TLR) activation in peripheral cells are well characterized but, although several TLRs are expressed on cells of the brain, the consequences of their activation on neuronal function remain to be fully investigated, particularly in the context of assessing their potential as therapeutic targets in neurodegenerative diseases. Several endogenous TLR ligands have been identified, many of which are soluble factors released from cells exposed to stressors. In addition, amyloid-ß (Aß) the main constituent of the amyloid plaques in Alzheimer's disease (AD), activates TLR2, although it has also been shown to bind to several other receptors. The objective of this study was to determine whether activation of TLR2 played a role in the developing inflammatory changes and Aß accumulation in a mouse model of AD. Wild type and transgenic mice that overexpress amyloid precursor protein and presenilin 1 (APP/PS1 mice) were treated with anti-TLR2 antibody for 7months from the age of 7-14months. We demonstrate that microglial and astroglial activation, as assessed by MHCII, CD68 and GFAP immunoreactivity was decreased in anti-TLR2 antibody-treated compared with control (IgG)-treated mice. This was associated with reduced Aß plaque burden and improved performance in spatial learning. The data suggest that continued TLR2 activation contributes to the developing neuroinflammation and pathology and may be provide a strategy for limiting the progression of AD.

Modified criteria for carotid sinus hypersensitivity are associated with increased mortality in a population-based study.

AIMS: Carotid sinus hypersensitivity (CSH) is arbitrarily defined as ≥3 s asystole or vasodepression of ≥50 mmHg in response to carotid sinus massage (CSM). Using this definition, 39% of older people meet the criteria for CSH. It has been suggested that current criteria are too sensitive. Krediet et al. [The history of diagnosing carotid sinus hypersensitivity: why are the current criteria too sensitive? Europace 2011;13:14-22] and Kerr et al. [Carotid sinus hypersensitivity in asymptomatic older persons: implications for diagnosis of syncope and falls. Arch Intern Med 2006;166:515-20] have proposed modified criteria. This population-based study aimed to compare the prevalence of CSH defined according to standard, Krediet and Kerr criteria, and to establish if CSH defined according these criteria is associated with all-cause mortality. METHODS AND RESULTS: A total of 272 community-dwelling people aged ≥65 were recruited at random. Carotid sinus massage was performed for 5 s in supine and head-up positions. Heart rate and blood pressure response were recorded using an electrocardiogram and photoplethysmography. Cox regression analysis was used to examine the association between each definition of CSH and all-cause mortality. The prevalence of CSH defined according to standard, Krediet, and Kerr criteria was 39, 52, and 10%, respectively. Seventy-one participants died over a mean follow-up of 8.6 years (SD 2.1). Carotid sinus hypersensitivity defined according to standard and Krediet criteria was not associated with survival. Carotid sinus hypersensitivity defined according to Kerr criteria was associated with all-cause mortality independent of age and sex [hazard ratio (HR) 2.023 (95% confidence interval (95% CI) 1.131-3.618) P = 0.018)]. This remained significant after adjusting for cardiovascular risk factors [HR 2.174 (1.075-3.900) P = 0.009]. CONCLUSION: Carotid sinus hypersensitivity defined according to Kerr criteria is associated with increased mortality. This raises an interesting question as to the suitability of the current criteria used to define CSH.

The communication experiences of patients with palliative care needs: A systematic review and meta-synthesis of qualitative findings.

OBJECTIVE: Optimal communication is essential in ensuring that the palliative care needs of patients are met. This continues to be an area of concern for healthcare providers. The goal of our present review was to gain a deeper understanding of the communication experiences of patients with palliative care needs that have been identified within the qualitative literature. METHOD: A systematic search for qualitative research papers was undertaken in February of 2012. Five databases (ASSIA, CINAHL, MEDLINE, PsychArticles, and PsychINFO) were searched using the search terms ["palliative care" OR "terminal care" OR "end of life care"] AND ["experience" OR "perspective" OR "qualitative" OR "interview"] AND ["patients" OR "clients" OR "service-user"]. Meta-synthesis was conducted on the data within the found papers. RESULTS: A line-of-argument synthesis of 15 studies yielded four overarching themes: talking-facilitating and inhibiting factors; the importance of humanitarian qualities within communication encounters; perceptions of autonomy within communication experiences; and individual differences in preferences for honesty within interactions. SIGNIFICANCE OF RESULTS: Our findings are discussed in relation to existing literature and offer a deeper insight into the communication experiences of this clinical population. A number of clinical implications are offered for the healthcare professionals who are providing support to patients with palliative care needs.

Improving care for patients with multiple long-term conditions admitted to hospital: challenges and potential solutions.

Increasing numbers of people live with multiple long-term conditions. These people are more likely to be admitted to hospital, experience adverse outcomes and receive poorer quality care than those with a single condition. Hospitals remain organised around a model of single-organ, disease-specific care which is not equipped to meet the needs of people living with multiple long-term conditions. This article considers these challenges and explores potential solutions. These include different service models to provide holistic, multidisciplinary inpatient and outpatient care across specialty boundaries, training a workforce to deliver high-quality hospital care for people living with multiple long-term conditions, and developing technological, financial and cultural enablers of change. Considerably more research is required to fully appreciate the shared risk factors, underlying mechanisms, patterns and consequences of multiple long-term conditions. This is essential to design and deliver better structures and processes of hospital care for people living with multiple long-term conditions.

A study protocol to investigate if acipimox improves muscle function and sarcopenia: an open-label, uncontrolled, before-and-after experimental medicine feasibility study in community-dwelling older adults.

INTRODUCTION: Sarcopenia is the age-associated loss of muscle mass and strength. Nicotinamide adenine dinucleotide (NAD) plays a central role in both mitochondrial function and cellular ageing processes implicated in sarcopenia. NAD concentrations are low in older people with sarcopenia, and increasing skeletal muscle NAD concentrations may offer a novel therapy for this condition. Acipimox is a licensed lipid-lowering agent known to act as an NAD precursor. This open-label, uncontrolled, before-and-after proof-of-concept experimental medicine study will test whether daily supplementation with acipimox improves skeletal muscle NAD concentrations. METHODS AND ANALYSIS: Sixteen participants aged 65 and over with probable sarcopenia will receive acipimox 250 mg and aspirin 75 mg orally daily for 4 weeks, with the frequency of acipimox administration being dependent on renal function. Muscle biopsy of the vastus lateralis and MRI scanning of the lower leg will be performed at baseline before starting acipimox and after 3 weeks of treatment. Adverse events will be recorded for the duration of the trial. The primary outcome, analysed in a per-protocol population, is the change in skeletal muscle NAD concentration between baseline and follow-up. Secondary outcomes include changes in phosphocreatine recovery rate by 31P magnetic resonance spectroscopy, changes in physical performance and daily activity (handgrip strength, 4 m walk and 7-day accelerometry), changes in skeletal muscle mitochondrial respiratory function, changes in skeletal muscle mitochondrial DNA copy number and changes in NAD concentrations in whole blood as a putative biomarker for future participant selection. ETHICS AND DISSEMINATION: The trial is approved by the UK Medicines and Healthcare Products Regulatory Agency (EuDRACT 2021-000993-28) and UK Health Research Authority and Northeast - Tyne and Wear South Research Ethics Committee (IRAS 293565). Results will be made available to participants, their families, patients with sarcopenia, the public, regional and national clinical teams, and the international scientific community. PROTOCOL: Acipimox feasibility study Clinical Trial Protocol V.2 2/11/21. TRIAL REGISTRATION NUMBER: The ISRCTN trial database (ISRCTN87404878).

Classical activation of microglia in CD200-deficient mice is a consequence of blood brain barrier permeability and infiltration of peripheral cells.

The interaction between CD200, expressed on several cell types, and its receptor CD200R, expressed on cells of the myeloid lineage, has been shown to be an important factor in modulating inflammation in macrophage function in several conditions including colitis and arthritis. More recently its modulatory effect on microglial activation has been identified and CD200-deficiency has been associated with increased microglial activation accompanied by increased production of inflammatory cytokines. The response of glia prepared from CD200-deficient mice to stimuli like lipopolysaccharide (LPS) is markedly greater than the response of cells prepared from wildtype mice and, consistent with this, is the recent observation that expression of Toll-like receptor (TLR)4 and signalling through NFκB are increased in microglia prepared from CD200-deficient mice. Here we show that glia from CD200-deficient mice are also more responsive to interferon-γ (IFNγ) which triggers classical activation of microglia. We investigated the effects of CD200-deficiency in vivo and report that there is an increase in expression of several markers of microglial activation including tumor necrosis factor (TNF)-α, which is a hallmark of classically-activated microglia. These changes are accompanied by increased IFNγ, and the evidence suggests that this is produced by infiltrating cells including T cells and macrophages. We propose that these cells enter the brain as a consequence of increased blood brain barrier (BBB) permeability in CD200-deficient mice and that infiltration is assisted by increased expression of the chemokines, monocyte chemotactic protein-1 (MCP-1), IFNγ-induced protein-10 (IP-10) and RANTES. This may have implications in neurodegenerative diseases where BBB permeability is compromised.

Visual Exploration While Walking With and Without Visual Cues in Parkinson's Disease: Freezer Versus Non-Freezer.

BACKGROUND: Visual cues can improve gait in Parkinson's disease (PD), including those experiencing freezing of gait (FOG). However, responses are variable and underpinning mechanisms remain unclear. Visuo-cognitive processing (measured through visual exploration) has been implicated in cue response, but this has not been comprehensively examined. OBJECTIVE: To examine visual exploration and gait with and without visual cues in PD who do and do not self-report FOG, and healthy controls (HC). METHODS: 17 HC, 21 PD without FOG, and 22 PD with FOG walked with and without visual cues, under single and dual-task conditions. Visual exploration (ie, saccade frequency, duration, peak velocity, amplitude, and fixation duration) was measured via mobile eye-tracking and gait (ie, gait speed, stride length, foot strike angle, stride time, and stride time variability) with inertial sensors. RESULTS: PD had impaired gait compared to HC, and dual-tasking made gait variables worse across groups (all P < .01). Visual cues improved stride length, foot strike angle, and stride time in all groups (P < .01). Visual cueing also increased saccade frequency, but reduced saccade peak velocity and amplitude in all groups (P < .01). Gait improvement related to changes in visual exploration with visual cues in PD but not HC, with relationships dependent on group (FOG vs non-FOG) and task (single vs dual). CONCLUSION: Visual cues improved visual exploration and gait outcomes in HC and PD, with similar responses in freezers and non-freezers. Freezer and non-freezer specific associations between cue-related changes in visual exploration and gait indicate different underlying visuo-cognitive processing within these subgroups for cue response.

Exploring the feasibility of technological visuo-cognitive training in Parkinson's: Study protocol for a pilot randomised controlled trial.

Visual and cognitive dysfunction are common in Parkinson's disease and relate to balance and gait impairment, as well as increased falls risk and reduced quality of life. Vision and cognition are interrelated (termed visuo-cognition) which makes intervention complex in people with Parkinson's (PwP). Non-pharmacological interventions for visuo-cognitive deficits are possible with modern technology, such as combined mobile applications and stroboscopic glasses, but evidence for their effectiveness in PwP is lacking. We aim to investigate whether technological visuo-cognitive training (TVT) can improve visuo-cognitive function in PwP. We will use a parallel group randomised controlled trial to evaluate the feasibility and acceptability of TVT versus standard care in PwP. Forty PwP who meet our inclusion criteria will be randomly assigned to one of two visuo-cognitive training interventions. Both interventions will be carried out by a qualified physiotherapist in participants own homes (1-hour sessions, twice a week, for 4 weeks). Outcome measures will be assessed on anti-parkinsonian medication at baseline and at the end of the 4-week intervention. Feasibility of the TVT intervention will be assessed in relation to safety and acceptability of the technological intervention, compliance and adherence to the intervention and usability of equipment in participants homes. Additionally, semi structured interviews will be conducted to explore participants' experience of the technology. Exploratory efficacy outcomes will include change in visual attention measured using the Trail Making Test as well as changes in balance, gait, quality of life, fear of falling and levels of activity. This pilot study will focus on the feasibility and acceptability of TVT in PwP and provide preliminary data to support the design of a larger, multi-centre randomised controlled trial. This trial is registered at isrctn.com (ISRCTN46164906).

MET-PREVENT: metformin to improve physical performance in older people with sarcopenia and physical prefrailty/frailty - protocol for a double-blind, randomised controlled proof-of-concept trial.

INTRODUCTION: Skeletal muscle dysfunction is central to both sarcopenia and physical frailty, which are associated with a wide range of adverse outcomes including falls and fractures, longer hospital stays, dependency and the need for care. Resistance training may prevent and treat sarcopenia and physical frailty, but not everyone can or wants to exercise. Finding alternatives is critical to alleviate the burden of adverse outcomes associated with sarcopenia and physical frailty. This trial will provide proof-of-concept evidence as to whether metformin can improve physical performance in older people with sarcopenia and physical prefrailty or frailty. METHODS AND ANALYSIS: MET-PREVENT is a parallel group, double-blind, placebo-controlled proof-of-concept trial. Trial participants can participate from their own homes, including completing informed consent and screening assessments. Eligible participants with low grip strength or prolonged sit-to-stand time together with slow walk speed will be randomised to either oral metformin hydrochloride 500 mg tablets or matched placebo, taken three times a day for 4 months. The recruitment target is 80 participants from two secondary care hospitals in Newcastle and Gateshead, UK. Local primary care practices will act as participant identification centres. Randomisation will be performed using a web-based minimisation system with a random element, balancing on sex and baseline walk speed. Participants will be followed up for 4 months post-randomisation, with outcomes collected at baseline and 4 months. The primary outcome measure is the four metre walk speed at the 4-month follow-up visit. ETHICS AND DISSEMINATION: The trial has been approved by the Liverpool NHS Research Ethics Committee (20/NW/0470), the Medicines and Healthcare Regulatory Authority (EudraCT 2020-004023-16) and the UK Health Research Authority (IRAS 275219). Results will be made available to participants, their families, patients with sarcopenia, the public, regional and national clinical teams, and the international scientific community. TRIAL REGISTRATION NUMBER: ISRCTN29932357.

Nogo receptor is involved in the adhesion of dendritic cells to myelin.

BACKGROUND: Nogo-66 receptor NgR1 and its structural homologue NgR2 are binding proteins for a number of myelin-associated inhibitory factors. After neuronal injury, these inhibitory factors are responsible for preventing axonal outgrowth via their interactions with NgR1 and NgR2 expressed on neurons. In vitro, cells expressing NgR1/2 are inhibited from adhering to and spreading on a myelin substrate. Neuronal injury also results in the presence of dendritic cells (DCs) in the central nervous system, where they can come into contact with myelin debris. The exact mechanisms of interaction of immune cells with CNS myelin are, however, poorly understood. METHODS: Human DCs were differentiated from peripheral blood monocytes and mouse DCs were differentiated from wild type and NgR1/NgR2 double knockout bone marrow precursors. NgR1 and NgR2 expression were determined with quantitative real time PCR and immunoblot, and adhesion of cells to myelin was quantified. RESULTS: We demonstrate that human immature myeloid DCs express NgR1 and NgR2, which are then down-regulated upon maturation. Human mature DCs also adhere to a much higher extent to a myelin substrate than immature DCs. We observe the same effect when the cells are plated on Nogo-66-His (binding peptide for NgR1), but not on control proteins. Mature DCs taken from Ngr1/2 knockout mice adhere to a much higher extent to myelin compared to wild type mouse DCs. In addition, Ngr1/2 knockout had no effect on in vitro DC differentiation or phenotype. CONCLUSIONS: These results indicate that a lack of NgR1/2 expression promotes the adhesion of DCs to myelin. This interaction could be important in neuroinflammatory disorders such as multiple sclerosis in which peripheral immune cells come into contact with myelin debris.

Single centre experience of ivabradine in postural orthostatic tachycardia syndrome.

AIMS: Postural orthostatic tachycardia syndrome (POTS) is associated with tachycardia on orthostasis. Patients frequently report palpitations, presyncope, and fatigue. Conventional therapy is effective in less than 60%. Case reports suggest ivabradine (a selective sinus node blocker, with no effect on blood pressure) may alleviate POTS-related symptoms. This is a retrospective case-series. METHODS AND RESULTS: Postural orthostatic tachycardia syndrome patients prescribed ivabradine were identified from the pharmacy database. Case notes were reviewed and participants completed a symptom assessment tool. Twenty-two patients were identified. Data were available from 20. Eight patients reported reduced tachycardia and fatigue and four reported only reduced tachycardia. The most common reason for discontinuing ivabradine was lack of efficacy (n = 6). Five patients reported side-effects resulting in two discontinuing treatment. CONCLUSION: This retrospective case series indicates that 60% of patients treated with ivabradine report a symptomatic improvement. A randomized controlled trial accessing the efficacy of ivabradine in POTS is indicated, particularly in patients resistant to, or intolerant of, conventional therapy.

Central nervous system dysfunction in primary biliary cirrhosis and its relationship to symptoms.

BACKGROUND & AIMS: Primary biliary cirrhosis (PBC) is associated with fatigue, memory impairment, and sleep disturbances. These symptoms suggest the possibility of underlying central nervous system (CNS) dysfunction. During exercise, fatigue develops due to muscular processes (peripheral fatigue) and decreased neurological activation of the muscle (central fatigue). In this study we objectively quantify central and peripheral fatigue in PBC and investigate the integrity of cortical inhibitory and excitatory circuits. Finally, we determine the relationship of these indices to the symptoms of PBC. METHODS: 16 early-stage PBC patients, 8 post-liver transplant PBC patients, and 12 age-matched controls were studied at the Specialist PBC clinic and neuroscience research unit. In these patients, twitch interpolation was used to measure peripheral and central fatigue. Paired-pulse trans-cranial magnetic stimulation was used to assess intra-cortical inhibition (ICI) and facilitation (ICF). RESULTS: PBC patients had a significantly lower central activation before fatiguing exercise (mean 86.6.8% (±12.75) vs. 95.2% (±7.4); p<0.05) and a greater response variability than controls. The decline in central activation during exercise and peripheral fatigue were normal. ICI was significantly reduced in PBC patients and daytime somnolence was greater in patients where net inhibition exceeded facilitation. Transplanted and non-transplanted patients had similar central activation, ICI, and ICF. CONCLUSIONS: PBC patients have impaired central activation and abnormal ICI, suggesting CNS abnormalities beyond voluntary control. Transplanted and non-transplanted patients show similar abnormalities raising interesting questions about the mechanisms underpinning these changes and the permanence of neurological dysfunction in PBC. ICI and ICF and the balance between them are related to daytime somnolence (an important symptom in PBC).