Promoting and measuring remyelination and neuroprotection in clinical trials of people with multiple sclerosis

The most tractable strategy to delay or prevent the progressive phase of MS is to promote endogenous remyelination; doing so restores nerve conduction and prevents demyelinated axons from degenerating. The rate-limiting stage in this process is differentiation of oligodendrocyte progenitor cells (OPCs) into mature, myelinating, oligodendrocytes. In animals, agonism of the retinoid X receptor (RXR)-γ enhances remyelination in this way. Metformin also promotes remyelination, this time by overcoming an age-associated block to the responsiveness of OPCs to pro-differentiation factors. In this PhD I show that bexarotene, a non-selective agonist of the RXR receptor, promotes remyelination in people with relapsing remitting multiple sclerosis. Converging evidence from electrophysiology and neuroimaging in a phase II clinical trial (CCMR One) demonstrate that this occurs in demyelinated lesions and is greatest in lesions located in grey matter regions of the brain. I additionally conducted analyses which suggest an age-dependency of bexarotene’s remyelinating effect and led a follow-up sub study of the trial participants which showed the treatment effect afforded by bexarotene is sustained, years after treatment. Unfortunately, bexarotene was poorly tolerated, and so the legacy of this trial will likely be one of shaping the framework for future assessments of remyelinating therapies. As such, I designed, obtained funding and secured approvals for a clinical trial to test the remyelinating effect of the combination of metformin with clemastine (CCMR Two), implementing lessons from CCMR One in the trial design; this is due to commence participant recruitment in 2021. In exploring treatments for progressive forms of MS, not limited to the process of remyelination, I worked with the MS Society to develop and implement a rigorous, expert-led, evidence-based approach to the selection of licensed drugs for repurposing and testing in clinical trials of people with progressive MS. I reviewed the preclinical and clinical literature for a list of compounds and condensed these into a database of summary documents. These were presented to a panel of experts and people affected by MS, ultimately leading to four treatments being recommended for immediate testing in progressive MS trials: R-α-lipoic acid, metformin, the combination treatment of R-α-lipoic acid and metformin, and niacin. Regrettably, much of my research has been halted by the COVID-19 pandemic. In this PhD I had additionally sought to evaluate electrophysiological techniques for quantifying remyelination and neuroprotection – multifocal VEP and saccadometry – in cohorts of people with MS and in the setting of the CCMR Two trial. Instead, when these studies were delayed, I embraced an opportunity to help the Cambridge COVID-19 research effort, working on the RECOVERY trial in the first wave, and leading my own project to analyse enrolment to treatment trials, ultimately describing the barriers to, and implications of, low recruitment rates in advance of the subsequent waves. Consequently, further exploratory research with electrophysiology and the CCMR Two trial will be the subject of post-doctoral research.Multiple Sclerosis Society of the United Kingdo

Effect of acute and chronic exercise on immunoendocrine responses in professional rugby union

Prolonged and intense exercise is known to modulate and suppress certain aspects of the immunoendocrine system. Such effects are thought to be largely mediated by the release of stress hormones and regulatory cytokines which originate from a variety of stress related paradigms in sport. These include acute physical exertion, chronic and repetitive exercise as well as other psychological and psychosocial aspects of training and competing in an elite environment. It may be of particular interest to study the effects of regular competition and training on immunoendocrine markers in rugby union players. At the professional level, rugby is an intense and physically demanding game where a significant amount of tissue trauma occurs as a result of the many game collisions. The aims of the studies outlined in this thesis were to determine the effects of acute, repeated and chronic exercise exposure on immunoendocrine markers and illness incidence in professional rugby union. Additional case studies were also undertaken to supplement main study findings. The first part of the thesis documented the effects of acute and repeated exercise on immunoendocrine markers in a cohort of international rugby union players. Data in study 1 showed that large disturbances in immunoendocine and hormone levels occur in players (n = 10) following game play. The magnitude of this response appeared dependent on game physicality (number of rucks/mauls, tackles) and the number of collisions players received during match play. Findings also showed suppression in host immunity, and in particular, innate immune function (neutrophil degranulation) which was not resolved 38 h (-29%) into the recovery period. In study 2, bloods were taken from players (n = 8) across a 21-day international rugby series. Data revealed that players entered the international camp with residual muscle damage (creatine kinase; CK) and inflammation (hs-CRP) following previous club involvement in European cup rugby. Further increases in stress related markers (cortisol, IL-6, CK, CRP) were not evident throughout the players time at the international training base. Conversely, a progressive increase in anabolic-catabolic balance (T/C ratio) was observed across time. In comparison to values on camp-entry (day 1), increases in T/C ratio were evident on day-5 (9.8%), day-7 (13%), day-19 (35%) and day-21 (45%) (P < 0.05). This data is suggestive of improved physiological recovery and was commensurate with team fitness goals (reduced volume + maintenance of training intensity) for that time. Findings suggest that monitoring of player club activities and training load preceding international duty is pertinent if they are required to represent their country inside 7 days. The second part of the thesis evaluated the stress induced effects of chronic rugby exposure in professional club players. Questionnaire data analysed from study 3 showed that players (n = 65) perceived current season length as being ‘too long’ (55%), ‘poorly structured’ (56%) and that game demands are increasing with time (52%). Furthermore, the majority of players (80%) felt that time ‘away’ from rugby was not sufficiently long enough and were in favour of a mid-season break (2 wks in duration). Investigation into the effects of chronic exercise on illness incidence, immunological and psychological state was carried out in a squad of club players (n = 30) over a competitive season (n = 48 wks) in studies 4-6. Findings revealed that specific periods in a rugby season resulted in disturbances to hormonal and immune status. These periods occurred following breaks in club game fixtures [November international and Six-nations period: February/early March], times of increased training intensity and increased ratio of conditioning/rugby activity. Peaks in number of upper respiratory illnesses (URIs) and disturbances in psychometric variables also occurred during these time periods. In 23% of all URIs, players reported that the presence of the illness either reduced activity (14.4%) or felt the need to go to bed (8.6%). Positional differences in variables were also observed. A higher incidence of URIs (3.4 vs 4.3) and lower concentrations of resting immune markers [salivary lysozyme: s-Lys (-31%); immunoglobulin A: s-IgA (-27%)] was observed in ‘backs’ (vs forwards) over the season. Higher mid-season cortisol levels was also observed in backs (P < 0.05) while conversely, greater concentrations of plasma CK and CRP were found in forwards throughout the season. These findings indicate positional specific differences in response to exercise load and point to the role of group specific recovery at certain times during the season. Data from study 6 showed that the number of training related complaints decreased across the season, findings which closely resembled corresponding decreases in plasma CRP values. This data is suggestive of a ‘repeated-bout’ effect or ‘contact adaptation’ in rugby union. Finally, comparison of methods used in the recording of illness data revealed that players were more honest when disclosing the existence of banal infections to a web-based training diary and under-reported infections to medical staff

The Role of Tight and Adherens Junctions in Cervical Neoplasia

Cervical cancer is the second most common cancer in women and is caused by a persistent infection of the cervical epithelium by the Human Papilloma Virus (HPV). Adherens (AJ) and tight junctions (TJ) play a key role in maintaining the apical-basolateral polarity and cohesive structure of epithelial cells. These junctions are maintained by the interaction of several key proteins including, claudins, catenins, cadherins and SNAIL. This study aims to identify the expression profile of several AJ and TJ proteins and to identify and genotype HPV DNA in several cases of cervical neoplasia. This study also aims to investigate the pathogenesis of aberrant AJ and TJ expression using cell based models. This study utilised a PCR based method to detect and genotype HPV DNA in 126 formalin-fixed paraffin embedded tissue samples. In tandem, tissue microarrays were produced from cervical biopsy samples and utilised to immunohistochemically examine the expression of several AJ and TJ proteins. The HeLa cervical cancer cell line was transfected with plasmids containing claudin-1 and claudin-7 genes to generate cell lines stably expressing claudin-1 claudin-7 respectively. Knockdown of SNAIL expression was performed in the SiHa cervical cancer cell line. An aberrant expression profile of AJ and TJ proteins was observed in cases of cervical neoplasia with increased expression of claudin-1, claudin-7, N-cadherin p120-catenin, SNAIL and decreased expression of E-cadherin compared to normal cervical epithelium. HPV DNA was detected and genotyped in 60 cervical tissue samples. HPV-16 was the most prevalent subtype, and was the subtype most associated with aberrant AJ and TJ expression. Knockdown of SNAIL expression had no effect on E-cadherin expression in SiHa cells while overexpression of claudin-1 and claudin-7 suppressed cellular motility in vitro, and decreased permeability in HeLa cells. This study identified aberrant expression of several AJ and TJ proteins which may be of potential use as biomarkers in the identification of pre-invasive cervical lesions. This study also identified that claudin-1 and claudin-7 overexpression in HeLa cells reduced cell migration and increased TEER values. This indicates the acquisition of invasive and metastatic properties in malignant cells is likely reliant on the synergistic interaction of several AJ and TJ proteins

Caring for Those Who Care the Most: Bill Wilson Center Wellness Program Assessment

Executive Summary Bill Wilson Center (BWC) is a community-based not-for-profit organization that provides mental health services, shelter, and support services to homeless youths and families in Santa Clara County. The agency currently has 137 staff members in the mental health division. The agency currently does not have an existing wellness program. The goal of this project is to evaluate the needs of the employees and what type of wellness activities they are interested in. BWC’s employees are the agency’s most valuable assets. Only through top performance can the agency continue to provide the highest level of services to more than 3,500 clients each year. BWC recognizes and acknowledges that the daily work performed by all staff in a social services environment, where caring for others is a top priority, can take its toll on a person’s health and well-being. The pressures of productivity goals, limited staff, funding priorities, and supporting clients with numerous problems can wear on the mental health professional, thus creating high levels of stress, compassion fatigue and employee turnover. In order for BWC to continue to provide the outstanding services it is known for, the staff at all levels of the organization must receive the support they need to perform their jobs. This includes the means to reduce or eliminate stress and feel valued for their hard work and dedication. Stress affects the health and the ability to function well at work and at home. Unmanaged stress can lead to an array of health-related problems, which is why BWC is proposing to introduce a wellness program to help the employees focus more on their own well-being. Wellness is a state of physical, mental, and social well-being, it is not merely the absence of disease or infirmity. The healthier the staff, the better they can serve their clients and help them achieve their own wellness. As this program is rolled out, the first issue to tackle at BWC is reducing stress levels among staff while keeping in mind what all staff members do in their daily work and how they do it. A wellness program adds value to an organization. The Wellness program will offer stress management classes, nutrition classes, and an exercise and fitness program. According to best practices literature, there are benefits and values to BWC having a wellness program and there is an inherent relationship between healthy employees and the related effects on retaining employees, reducing healthcare costs, decreasing rates of illness and injuries, reducing employee absenteeism, and improving employee morale. A worksite wellness program for employees includes the following benefits: improved physical fitness, increased stamina, lower levels of stress, increased well-being, self-image, and self-esteem. It is the agency’s goal that as the program progresses, some of the activities introduced through the wellness program will be available to clients as well as staff. Furthermore, there is the expectation that there will be opportunities to partner with primary healthcare providers will better address the broad health needs of the agency clients. The methods used included health risk assessment (HRA) surveys and focus groups questionnaires. The survey and focus groups results yielded the following shared interest: 1) stress management, 2) nutrition, 3) financial planning, and 4) compassion fatigue debriefing, work/ life balance followed by interests in 5) self-care and in parenting classes. It is recommendation that BWC continues to develop the wellness program for staff which can be later translatable to its clients. By ensuring staff are content in their jobs and are working at their most productive level, BWC will ensure the highest level of services for its clients

Applying optimal control theory to a spatial simulation model of sudden oak death: ongoing surveillance protects tanoak while conserving biodiversity.

Sudden oak death has devastated tree populations across California. However, management might still slow disease spread at local scales. We demonstrate how to unambiguously characterize effective, local management strategies using a detailed, spatially explicit simulation model of spread in a single forest stand. This pre-existing, parameterized simulation is approximated here by a carefully calibrated, non-spatial model, explicitly constructed to be sufficiently simple to allow optimal control theory (OCT) to be applied. By lifting management strategies from the approximate model to the detailed simulation, effective time-dependent controls can be identified. These protect tanoak-a culturally and ecologically important species-while conserving forest biodiversity within a limited budget. We also consider model predictive control, in which both the approximating model and optimal control are repeatedly updated as the epidemic progresses. This allows management which is robust to both parameter uncertainty and systematic differences between simulation and approximate models. Including the costs of disease surveillance then introduces an optimal intensity of surveillance. Our study demonstrates that successful control of sudden oak death is likely to rely on adaptive strategies updated via ongoing surveillance. More broadly, it illustrates how OCT can inform effective real-world management, even when underpinning disease spread models are highly complex.BBSRC DTP Studentshi

Regional Growth Rate Differences Specified by Apical Notch Activities Regulate Liverwort Thallus Shape

Plants have undergone 470 million years of evolution on land and different groups have distinct body shapes. Liverworts are the most ancient land plant lineage and have a flattened, creeping body (the thallus), which grows from apical cells in an invaginated "notch." The genetic mechanisms regulating liverwort shape are almost totally unknown, yet they provide a blueprint for the radiation of land plant forms. We have used a combination of live imaging, growth analyses, and computational modeling to determine what regulates liverwort thallus shape in $\textit{Marchantia polymorpha}$. We find that the thallus undergoes a stereotypical sequence of shape transitions during the first 2 weeks of growth and that key aspects of global shape depend on regional growth rate differences generated by the coordinated activities of the apical notches. A "notch-drives-growth" model, in which a diffusible morphogen produced at each notch promotes specified isotropic growth, can reproduce the growth rate distributions that generate thallus shape given growth suppression at the apex. However, in surgical experiments, tissue growth persists following notch excision, showing that this model is insufficient to explain thallus growth. In an alternative "notch-pre-patterns-growth" model, a persistently acting growth regulator whose distribution is pre-patterned by the notches can account for the discrepancies between growth dynamics in the notch-drives-growth model and real plants following excision. Our work shows that growth rate heterogeneity is the primary shape determinant in $\textit{Marchantia polymorpha}$ and suggests that the thallus is likely to have zones with specialized functions.We thank the BBSRC ( BB/F016581/1 ) for funding J.E.S.’s PhD research and the Gatsby Charitable Foundation ( GAT2962 ) and the Royal Society (RG54416) for funding C.J.H.’s research

Optimal strategies to protect a sub-population at risk due to an established epidemic.

Epidemics can particularly threaten certain sub-populations. For example, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the elderly are often preferentially protected. For diseases of plants and animals, certain sub-populations can drive mitigation because they are intrinsically more valuable for ecological, economic, socio-cultural or political reasons. Here, we use optimal control theory to identify strategies to optimally protect a 'high-value' sub-population when there is a limited budget and epidemiological uncertainty. We use protection of the Redwood National Park in California in the face of the large ongoing state-wide epidemic of sudden oak death (caused by Phytophthora ramorum) as a case study. We concentrate on whether control should be focused entirely within the National Park itself, or whether treatment of the growing epidemic in the surrounding 'buffer region' can instead be more profitable. We find that, depending on rates of infection and the size of the ongoing epidemic, focusing control on the high-value region is often optimal. However, priority should sometimes switch from the buffer region to the high-value region only as the local outbreak grows. We characterize how the timing of any switch depends on epidemiological and logistic parameters, and test robustness to systematic misspecification of these factors due to imperfect prior knowledge

Optimising reactive disease management using spatially explicit models at the landscape scale

Increasing rates of global trade and travel, as well as changing climatic patterns, have led to more frequent outbreaks of plant disease epidemics worldwide. Mathematical modelling is a key tool in predicting where and how these new threats will spread, as well as in assessing how damaging they might be. Models can also be used to inform disease management, providing a rational methodology for comparing the performance of possible control strategies against one another. For emerging epidemics, in which new pathogens or pathogen strains are actively spreading into new regions, the spatial component of spread becomes particularly important, both to make predictions and to optimise disease control. In this chapter we illustrate how the spatial spread of emerging plant diseases can be modelled at the landscape scale via spatially explicit compartmental models. Our particular focus is on the crucial role of the dispersal kernel-which parameterises the probability of pathogen spread from an infected host to susceptible hosts at any given distance-in determining outcomes of epidemics. We add disease management to our model by testing performance of a simple "one off" form of reactive disease control, in which sites within a particular distance of locations detected to contain infection are removed in a single round of disease management. We use this simplified model to show how ostensibly arcane decisions made by the modeller-most notably whether or not the underpinning disease model allows for stochasticity (i.e. randomness)-can greatly impact on disease management recommendations. Our chapter is accompanied by example code in the programming language R available via an online repository, allowing the reader to run the models we present for him/herself

An ecophysiological model of plant-pest interactions: the role of nutrient and water availability.

Empirical studies have shown that particular irrigation/fertilization regimes can reduce pest populations in agroecosystems. This appears to promise that the ecological concept of bottom-up control can be applied to pest management. However, a conceptual framework is necessary to develop a mechanistic basis for empirical evidence. Here, we couple a mechanistic plant growth model with a pest population model. We demonstrate its utility by applying it to the peach-green aphid system. Aphids are herbivores which feed on the plant phloem, deplete plants' resources and (potentially) transmit viral diseases. The model reproduces system properties observed in field studies and shows under which conditions the diametrically opposed plant vigour and plant stress hypotheses find support. We show that the effect of fertilization/irrigation on the pest population cannot be simply reduced as positive or negative. In fact, the magnitude and direction of any effect depend on the precise level of fertilization/irrigation and on the date of observation. We show that a new synthesis of experimental data can emerge by embedding a mechanistic plant growth model, widely studied in agronomy, in a consumer-resource modelling framework, widely studied in ecology. The future challenge is to use this insight to inform practical decision making by farmers and growers