Studying glomerular disease epidemiology: tackling challenges and paving a path forward

Background: Glomerular diseases are a group of rare immune-mediated kidney diseases that affect the glomeruli, or filtering units, of the kidney. Major knowledge gaps remain in our understanding of glomerular disease epidemiology. Efforts to describe glomerular disease distributions based on geographic, demographic, and temporal factors (descriptive epidemiology) are limited by the absence of population-level disease registries in most jurisdictions. The extent to which glomerular disease subtype independently associates with clinical outcomes (analytic epidemiology), especially once kidney disease has progressed to end-stage kidney failure, remains largely unknown. Further, much of what is known regarding glomerular disease epidemiology is derived from the experiences of highly-selected patient populations enrolled in clinical trials or attending academic medical centres. Larger-scale, population-level, studies of glomerular disease epidemiology would help to close knowledge gaps regarding the distribution and determinants of glomerular disease and, in doing so, would inform clinical care, public health policy, and clinical trial design. Hypotheses: Two major hypotheses are explored in this thesis: 1. Significant geographic and temporal variation in glomerular disease frequencies exist, that are not solely explained by racial-ethnic variation, thus supporting a role for socioeconomic and environmental factors in the development of clinically manifest glomerular disease; 2. Glomerular disease subtype independently associates with clinical outcomes even after glomerular disease has advanced to end-stage kidney failure, challenging the prevailing paradigm to group all glomerular disease subtypes together in research and public health reporting of clinical outcomes in patients with end-stage kidney failure. Aims: The overall aim of this research was to close knowledge gaps in glomerular disease epidemiology by identifying geographic and temporal variation in glomerular disease frequency distributions and by determining associations between glomerular disease subtype and clinical outcomes (mortality, cardiovascular events) in patients with end-stage kidney failure. Methods: For the first two manuscripts (Chapters 3 and 4), I analysed two large-scale pathology datasets created by my collaborator, Dr. Charles Jeannette: a) the International Kidney Biopsy Survey (IKBS) that includes kidney biopsy diagnoses and associated patient demographics from 29 international kidney pathology laboratories, which I used to study geographic variation in glomerular disease frequencies within and across racial-ethnic groups; b) the Glomerular Disease Collaborative Network (GDCN), a registry of all kidney biopsies referred to the University of North Carolina since 1986, which I used to study temporal trends in glomerular disease frequencies within and across demographic groups over the last three decades. For the next two manuscripts (Chapters 5 and 6), I analysed data – including physician-reported cause of kidney failure – from virtually all U.S. patients with treated end-stage kidney failure who are enrolled, by federal mandate, in the United States Renal Data System (USRDS). In the first of these two manuscripts, I determined associations between glomerular disease subtype and mortality; in the second, I determined associations between glomerular disease subtype and cardiovascular events. Advanced statistical methods included multivariable regression to handle confounding, proportional sub-distribution hazard models to handle competing events, and multiple imputation to handle missing data. Results: Major findings from these manuscripts include: a) significant differences in glomerular disease frequencies across continents, even among patients with similar racial-ethnic backgrounds; b) significant temporal trends in the relative frequencies of many biopsy-proven glomerular diseases, including stabilization in the 21st century of the rapid increase in focal segmental glomerulosclerosis observed at the end of the 20th century, and a dramatic increase in diabetic glomerulosclerosis over time, to become the second most frequent biopsy-proven glomerular disease diagnosis in the modern era; c) significant differences in the hazards of mortality and cardiovascular events across glomerular disease subtypes, even after accounting for between-group differences in case-mix. Conclusions: In addition to answering specific research questions regarding glomerular disease epidemiology, this research exemplifies the strengths and feasibility of population-level, internationally collaborative, approaches to studying glomerular diseases. Findings from these studies can shape public health policy (e.g. promotion of healthy lifestyle approaches to curb the high frequency of diabetic glomerulosclerosis in contemporary U.S. populations), future research design (e.g. recognising the importance of glomerular disease subtype as a prognostic indicator in studies involving patients with end-stage kidney failure), and clinical care (e.g. formulating differential diagnoses based on patient demographics, or counselling U.S. patients regarding their absolute and relative risks of mortality and cardiovascular events following dialysis initiation)

Nutrient transporter expression in both the placenta and fetal liver are affected by maternal smoking

ACKNOWLEGDEMENTS Authors would like to thank the nurses of ward 309 (Aberdeen Royal Infirmary) for consenting participants and NHS Grampian Biorepository staff. Also, Gary Cameron for performing the LC-MS/MS cotinine analyses and Ms Linda Robertson for technical assistance. The authors state there are no conflicts of interest. Author contributions: NW, PF and PAF designed the research; NW conducted research, analysed data and wrote paper; PAF responsible for ethics (SAFeR study). All authors read and approved the final manuscript. Authors would like to thank the study funders: Glasgow Children’s Hospital Charity YRSS/PHD/2016/05 and UK Medical Research Council: MR/L010011/1, to PAF & PJOS and MR/P011535/1 to PAF. The funders played no role in the conduct, analysis or publication of the studyPeer reviewedPublisher PD

Placental transporter localization and expression in the Human : the importance of species, sex, and gestational age differences

Grant Support: This work was supported by the Medical Research Council, UK (MR/L010011/1 to PAF, PJOS) and a Glasgow Children's Hospital Charity Research Fund and University of Aberdeen, UK, Elphinstone Scholarship to NW.Peer reviewedPublisher PD

STarT Back Tool risk stratification is associated with changes in movement profile and sensory discrimination in low back pain: A study of 290 patients

Background: Investigation of movement and sensory profiles across STarT Back risk subgroups. Methods: A chronic low back pain cohort (n = 290) were classified as low, medium or high risk using the STarT Back Tool, and completed a repeated spinal bending task and quantitative sensory testing. Pain summation, time taken and the number of protective behaviours with repeated bending were measured. Sensory tests included two-point discrimination, temporal summation, pressure/thermal pain thresholds and conditioned pain modulation. Subgroups were profiled against movement and sensory variables. Results: The high-risk subgroup demonstrated greater pain summation following repeated forward bending (p < 0.001). The medium-risk subgroup demonstrated greater pain summation following repeated backward bending (p = 0.032). Medium- and high-risk subgroups demonstrated greater forward/backward bend time compared to the low-risk subgroup (p = 0.001, p = 0.005, respectively). Medium- and high-risk subgroups demonstrated a higher number of protective behaviours per forward bend compared to the low-risk subgroup (p = 0.008). For sensory variables, only two-point discrimination differed between subgroups, with medium- and high-risk subgroups demonstrating higher thresholds (p = 0.016). Conclusions: This study showed altered movement characteristics and sensory discrimination across SBT risk subgroups in people with CLBP. Membership of the high SBT risk subgroup was associated with greater pain and disability levels, greater pain summation following repeated bending, slower bending times, a greater number of protective behaviours during forward bending, and a higher TPD threshold. Treatment outcomes for higher risk SBT subgroups may be enhanced by interventions specifically targeting movement and sensory alterations. Significance: In 290 people with chronic low back pain movement profile and two-point discrimination threshold differed across risk subgroups defined by the STarT Back Tool. Conversely, pain sensitivity did not differ across these subgroups. These findings may add further guidance for targeted care in these subgroups

Spatial analysis of Cdc42 activity reveals a role for plasma membrane–associated Cdc42 in centrosome regulation

The ability of the small GTPase Cdc42 to regulate diverse cellular processes depends on tight spatial control of its activity. Cdc42 function is best understood at the plasma membrane (PM), where it regulates cytoskeletal organization and cell polarization. Active Cdc42 has also been detected at the Golgi, but its role and regulation at this organelle are only partially understood. Here we analyze the spatial distribution of Cdc42 activity by moni­toring the dynamics of the Cdc42 FLARE biosensor using the phasor approach to FLIM-FRET. Phasor analysis revealed that Cdc42 is active at all Golgi cisternae and that this activity is controlled by Tuba and ARHGAP10, two Golgi-associated Cdc42 regulators. To our surprise, FGD1, another Cdc42 GEF at the Golgi, was not required for Cdc42 regulation at the Golgi, although its depletion decreased Cdc42 activity at the PM. Similarly, changes in Golgi morphology did not affect Cdc42 activity at the Golgi but were associated with a substantial reduction in PM-associated Cdc42 activity. Of interest, cells with reduced Cdc42 activity at the PM displayed altered centrosome morphology, suggesting that centrosome regulation may be mediated by active Cdc42 at the PM. Our study describes a novel quantitative approach to determine Cdc42 activity at specific subcellular locations and reveals new regulatory principles and functions of this small GTPase

Dose-response effects of light at night on the reproductive physiology of great tits (Parus major): integrating morphological analyses with candidate gene expression

Artificial light at night (ALAN) is increasingly recognized as a potential threat to wildlife and ecosystem health. Among the ecological effects of ALAN, changes in reproductive timing are frequently reported, but the mechanisms underlying this relationship are still poorly understood. Here, we experimentally investigated these mechanisms by assessing dose‐dependent photoperiodic responses to ALAN in the great tit (Parus major). We individually exposed photosensitive male birds to one of three nocturnal light levels (0.5, 1.5, and 5 lux), or to a dark control. Subsequent histological and molecular analyses on their testes indicated a dose‐dependent reproductive response to ALAN. Specifically, different stages of gonadal growth were activated after exposure to different levels of light at night. mRNA transcript levels of genes linked to the development of germ cells (stra8 and spo11) were increased under 0.5 lux compared to the dark control. The 0.5 and 1.5 lux groups showed slight increases in testis size and transcript levels associated with steroid synthesis (lhr and hsd3b1) and spermatogenesis (fshr, wt1, sox9, and cldn11), although spermatogenesis was not detected in histological analysis. In contrast, all birds under 5 lux had 10 to 30 times larger testes than birds in all other groups, with a parallel strong increase in mRNA transcript levels and clear signs of spermatogenesis. Across treatments, the volume of the testes was generally a good predictor of testicular transcript levels. Overall, our findings indicate that even small changes in nocturnal light intensity can increase, or decrease, effects on the reproductive physiology of wild organisms

Alternative (backdoor) androgen production and masculinization in the human fetus

Funding: The study was supported by the following grants: Chief Scientist Office (Scottish Executive, CZG/4/742) (PAF and PJOS) (http://www.cso.scot.nhs.uk/funding-2/); NHS Grampian Endowments 08/02 (PAF and PJOS) and 15/1/010 (PAF, PF, US, and PJOS) (https://www.nhsgcharities.com/); the Glasgow Children’s Hospital Research Charity Research Fund, YRSS/PHD/2016/05 (NW, MB, PJOS, and PAF) (http://www.glasgowchildrenshospitalcharity.org/research/glasgow-childrens-hospital-charity-research-fund); the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement number 212885 (PAF) (https://ec.europa.eu/research/fp7/index_en.cfm); Medical Research Council Grants MR/L010011/1 (PAF and PJOS) and MR/K501335/1 (MB, PAF, and PJOS) (https://mrc.ukri.org/); and the Kronprinsessan Lovisas Foundation, “Stiftelsen Gunvor och Josef Anérs,” the “Stiftelsen Jane och Dan Olssons,” and the “Stiftelsen Tornspiran” (KS and OS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Spatial analysis of Cdc42 activity reveals a role for plasma membrane–associated Cdc42 in centrosome regulation

The ability of the small GTPase Cdc42 to regulate diverse cellular processes depends on tight spatial control of its activity. Cdc42 function is best understood at the plasma membrane (PM), where it regulates cytoskeletal organization and cell polarization. Active Cdc42 has also been detected at the Golgi, but its role and regulation at this organelle are only partially understood. Here we analyze the spatial distribution of Cdc42 activity by monitoring the dynamics of the Cdc42 FLARE biosensor using the phasor approach to FLIM-FRET. Phasor analysis revealed that Cdc42 is active at all Golgi cisternae and that this activity is controlled by Tuba and ARHGAP10, two Golgi-associated Cdc42 regulators. To our surprise, FGD1, another Cdc42 GEF at the Golgi, was not required for Cdc42 regulation at the Golgi, although its depletion decreased Cdc42 activity at the PM. Similarly, changes in Golgi morphology did not affect Cdc42 activity at the Golgi but were associated with a substantial reduction in PM-associated Cdc42 activity. Of interest, cells with reduced Cdc42 activity at the PM displayed altered centrosome morphology, suggesting that centrosome regulation may be mediated by active Cdc42 at the PM. Our study describes a novel quantitative approach to determine Cdc42 activity at specific subcellular locations and reveals new regulatory principles and functions of this small GTPase

Long-term exposure to chemicals in sewage sludge fertilizer alters liver lipid content in females and cancer marker expression in males

This work was supported by the SRF Academic Scholarship Award 2013 (to PAF, PJOS, PF), the Wellcome Trust (080388 to PAF, CC, SMR, RMS, NPE) and the European Community’s Seventh Framework Programme (FP7 ⁄ 2007-2013 to PAF, SMR, CC) under grant agreement no 212885. The authors would like to thank Ms Margaret Fraser and the Proteomics Core Facility at the University of Aberdeen and Ms Carol E. Kyle and as Dr Stewart Rhind (deceased) at James Hutton Institute, Aberdeen, for their important contributions to this study. Supplementary material and research data are available at https://doi.org/10.1016/j.envint.2019.01.003Peer reviewedPublisher PD

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29