The Role of Virtual Reality in the Management of Irritable Bowel Syndrome.

PURPOSE OF REVIEW: Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction that significantly impacts health-related quality of life (HRQOL). This article explores the potential role of virtual reality (VR)-based cognitive behavioral therapy (CBT) in treating patients with IBS. RECENT FINDINGS: While CBT is a proven, skills-based therapy approach that modifies behaviors and alters dysfunctional thinking patterns to influence the gut-brain axis and improve IBS symptoms, it is rarely prescribed given a paucity of CBT-trained clinicians. We developed a novel VR program that delivers a standardized CBT program over an 8-week period to help patients manage their symptoms. In initial qualitative validation testing, patients expressed positive perceptions about using VR CBT for IBS. Home-based, standardized VR CBT has the potential to be an effective and scalable treatment option for patients with IBS. While initial studies have shown proof-of-concept definitive randomized controlled trials are needed to demonstrate the efficacy of self-administered VR CBT in IBS.

The Costs (and Benefits?) of Effortful Listening for Older Adults: Insights from Simultaneous Electrophysiology, Pupillometry, and Memory.

Although the impact of acoustic challenge on speech processing and memory increases as a person ages, older adults may engage in strategies that help them compensate for these demands. In the current preregistered study, older adults (n = 48) listened to sentences-presented in quiet or in noise-that were high constraint with either expected or unexpected endings or were low constraint with unexpected endings. Pupillometry and EEG were simultaneously recorded, and subsequent sentence recognition and word recall were measured. Like young adults in prior work, we found that noise led to increases in pupil size, delayed and reduced ERP responses, and decreased recall for unexpected words. However, in contrast to prior work in young adults where a larger pupillary response predicted a recovery of the N400 at the cost of poorer memory performance in noise, older adults did not show an associated recovery of the N400 despite decreased memory performance. Instead, we found that in quiet, increases in pupil size were associated with delays in N400 onset latencies and increased recognition memory performance. In conclusion, we found that transient variation in pupil-linked arousal predicted trade-offs between real-time lexical processing and memory that emerged at lower levels of task demand in aging. Moreover, with increased acoustic challenge, older adults still exhibited costs associated with transient increases in arousal without the corresponding benefits.

Graded and ungraded expectation patterns: Prediction dynamics during active comprehension.

Language comprehension can be facilitated by the accurate prediction of upcoming words, but prediction effects are not ubiquitous, and comprehenders likely use predictive processing to varying degrees depending on task demands. To ascertain the processing consequences of prioritizing prediction, we here compared ERPs elicited when young adult participants simply read for comprehension with those collected in a subsequent block that required active prediction. We were particularly interested in frontally-distributed post-N400 effects for expected and unexpected words in strongly constraining contexts, which have previously been documented as two distinct patterns: an enhanced positivity ("anterior positivity") observed for prediction violations compared to words that are merely unpredictable (because they occur in weakly constraining sentences) and a distinction between expected endings in more constraining contexts and those same weakly constrained words ("frontal negativity" to the strongly predicted words). We found that the size of the anterior positivity effect was unchanged between passive comprehension and active prediction, suggesting that some processes related to prediction may engage state-like networks. On the other hand, the frontal negativity showed graded patterns from the interaction of task and sentence type. These differing patterns support the hypothesis that there are two separate effects with frontal scalp distributions that occur after the N400 and further suggest that the impact of violating predictions (as long as prediction is engaged at all) is largely stable across varying levels of effort/attention directed toward prediction, whereas other comprehension processes can be modulated by task demands.

To err is human- to understand error-processing is divine: Contributions of working memory and anxiety to error-related brain and pupil responses.

Both anxiety and working memory capacity appear to predict increased (more negative) error-related negativity (ERN) amplitudes, despite being inversely related to one another. Until the interactive effects of these variables on the ERN are clarified, there may be challenges posed to our ability to use the ERN as an endophenotype for anxiety, as some have suggested. The compensatory error monitoring hypothesis suggests that high trait-anxiety individuals have larger ERN amplitudes because they must employ extra, compensatory efforts to override the working memory demands of their anxiety. Yet, to our knowledge, no ERN study has employed direct manipulation of working memory demands in conjunction with direct manipulations of induced (state) anxiety. Furthermore, little is known about how these manipulations affect other measures of error processing, such as the error-related pupil dilation response and post-error behavioral adjustments. Therefore, we manipulate working memory load and anxiety in a 2 × 2 within-subjects design to examine the interactive effects of working memory load and anxiety on ERN amplitude, error-related pupil dilation response amplitude, and post-error behavior. There were no effects of our manipulations on ERN amplitude, suggesting a strong interpretation of compensatory error-processing theory. However, our worry manipulation affected post-error behavior, such that worry caused a reduction in post-error accuracy. Additionally, our working memory manipulation affected error-related PDR magnitude and the amplitude of the error-related positivity (Pe), such that increased working memory load decreased the amplitude of these responses. Implications of these results within the context of the compensatory error processing framework are discussed.

Disruption to left inferior frontal cortex modulates semantic prediction effects in reading and subsequent memory: Evidence from simultaneous TMS-EEG.

Readers use prior context to predict features of upcoming words. When predictions are accurate, this increases the efficiency of comprehension. However, little is known about the fate of predictable and unpredictable words in memory or the neural systems governing these processes. Several theories suggest that the speech production system, including the left inferior frontal cortex (LIFC), is recruited for prediction but evidence that LIFC plays a causal role is lacking. We first examined the effects of predictability on memory and then tested the role of posterior LIFC using transcranial magnetic stimulation (TMS). In Experiment 1, participants read category cues, followed by a predictable, unpredictable, or incongruent target word for later recall. We observed a predictability benefit to memory, with predictable words remembered better than unpredictable words. In Experiment 2, participants performed the same task with electroencephalography (EEG) while undergoing event-related TMS over posterior LIFC using a protocol known to disrupt speech production, or over the right hemisphere homologue as an active control site. Under control stimulation, predictable words were better recalled than unpredictable words, replicating Experiment 1. This predictability benefit to memory was eliminated under LIFC stimulation. Moreover, while an a priori ROI-based analysis did not yield evidence for a reduction in the N400 predictability effect, mass-univariate analyses did suggest that the N400 predictability effect was reduced in spatial and temporal extent under LIFC stimulation. Collectively, these results provide causal evidence that the LIFC is recruited for prediction during silent reading, consistent with prediction-through-production accounts.

Updating the relationship of the Ne/ERN to task-related behavior: A brief review and suggestions for future research.

The error negativity/error-related negativity (Ne/ERN) is one of the most well-studied event-related potential (ERP) components in the electroencephalography (EEG) literature. Peaking about 50 ms after the commission of an error, the Ne/ERN is a negative deflection in the ERP waveform that is thought to reflect error processing in the brain. While its relationships to trait constructs such as anxiety are well-documented, there is still little known about how the Ne/ERN may subsequently influence task-related behavior. In other words, does the occurrence of the Ne/ERN trigger any sort of error corrective process, or any other behavioral adaptation to avoid errors? Several theories have emerged to explain how the Ne/ERN may implement or affect behavior on a task, but evidence supporting each has been mixed. In the following manuscript, we review these theories, and then systematically discuss the reasons that there may be discrepancies in the literature. We review both the inherent biological factors of the neural regions that underlie error-processing in the brain, and some of the researcher-induced factors in analytic and experimental choices that may be exacerbating these discrepancies. We end with a table of recommendations for future researchers who aim to understand the relationship between the Ne/ERN and behavior.

Virtual Reality: A New Treatment Paradigm for Disorders of Gut-Brain Interaction?

Disorders of gut-brain interaction (DGBIs), previously called functional bowel disorders, are prevalent, reduce patients' quality of life, and impose a significant negative economic impact on the health care system. Functional dyspepsia and irritable bowel syndrome (IBS) are 2 of the most common DGBIs. An overlying, and in many cases unifying, symptom for many of these disorders is the presence of abdominal pain. Chronic abdominal pain can be difficult to treat, as many antinociceptive agents are associated with side effects that limit their use and other agents may only partially improve, but not completely relieve, all aspects of the pain. Novel therapies to alleviate chronic pain and the other symptoms that characterize DGBIs are thus needed. Virtual reality (VR), a technology that immerses patients in a multisensory experience, has been shown to relieve pain in burn victims and other instances of somatic pain. Two recent novel studies have demonstrated that VR has the potential to play an important role in the treatment of functional dyspepsia and IBS. This article examines the development of VR, its role in the treatment of somatic and visceral pain, and its potential position in the treatment of DGBIs.

A decade of Clostridioides difficile infection: a constant challenge to maintain the status quo.

INTRODUCTION: Clostridioides difficile infection (CDI) is a leading cause of healthcare-associated (HA) diarrhoea. We retrospectively investigated data from a comprehensive, multidisciplinary C. difficile surveillance programme focusing on hospitalized patients in a tertiary Irish hospital over 10 years. METHODS: Data from 2012 to 2021 were extracted from a centralized database, including patient demographics, admission, case and outbreak details, ribotypes (RTs), and (since 2016) antimicrobial exposures and CDI treatments. Counts of CDI by origin of infection were explored using ꭓ2 analyses, Poisson regression was used to investigate trends in rates of CDI and possible risk factors. Time to recurrent CDI was examined by a Cox proportional hazards regression. RESULTS: Over 10 years, 954 CDI patients had a 9% recurrent CDI rate. CDI testing requests occurred in only 22% of patients. Most CDIs were HA (82.2%) and affected females (odds ratio: 2.3, P<0.01). Fidaxomicin significantly reduced the hazard ratio of time to recurrent CDI. No trends in HA-CDI incidence were observed despite key time-point events and increasing hospital activity. In 2021, community-associated (CA)-CDI increased. RTs did not differ for HA versus CA for the most common RTs (014, 078, 005 and 015). Average length-of-stay differed significantly between HA (67.1 days) and CA (14.6 days) CDI. CONCLUSION: HA-CDI rates remained unchanged despite key events and increased hospital activity, whereas by 2021, CA-CDI was at its highest in a decade. The convergence of CA and HA RTs, and the proportion of CA-CDI, question the relevance of current case definitions when increasingly patients receive hospital care without an overnight hospital stay.

Older Adults Show Intraindividual Variation in the Use of Predictive Processing.

BACKGROUND: The use of prediction can aid language comprehension through preactivation of relevant word features. However, predictions can be wrong, and it has been proposed that resolving the mismatch between the predicted and presented item requires cognitive resources. Older adults tend not to predict and instead rely more on passive comprehension. Here, we tested, using an intraindividual approach, whether older adults consistently use this less demanding processing strategy while reading or whether they attempt to predict on some trials. METHODS: We used a cross-task conflict paradigm. Younger and older participants self-paced to read sentences that ended with either an expected or unexpected word. Each sentence was then followed by a flanker stimulus that could be congruent or incongruent. We examined responses within and across the two tasks. RESULTS: Unexpected words were in general read as quickly as expected words, indicating that typical processing of these words was similar. However, for both younger and older adults, there was a greater proportion of very slow trials for unexpected words, revealing different processing on a subset of trials. Critically, in older adults, these slowly read unexpected words engaged control, as seen in speeded responses to incongruent flanker stimuli. CONCLUSION: Using a cross-task conflict paradigm, we showed that older adults are able to predict and engage cognitive resources to cope with prediction violations, but do not opt to use these processes consistently.

The Effects of Captioning Errors, Background Noise, and Hearing Loss on Memory for Text-Captioned Speech.

PURPOSE: Previous studies have suggested that the negative effects of acoustic challenge on speech memory can be attenuated with assistive text captions, particularly among older adults with hearing impairment. However, no studies have systematically examined the effects of text-captioning errors, which are common in automated speech recognition (ASR) systems. METHOD: In two experiments, we examined memory for text-captioned speech (with and without background noise) when captions had no errors (control) or had one of three common ASR errors: substitution, deletion, or insertion errors. RESULTS: In both Experiment 1 (young adults with normal hearing) and Experiment 2 (older adults with varying hearing acuity), we observed similar additive effects of caption errors and background noise, such that increased background noise and the presence of captioning errors negatively impacted memory outcomes. Notably, the negative effects of captioning errors were largest among older adults with increased hearing thresholds, suggesting that older adults with hearing loss may show an increased reliance on text captions compared to adults with normal hearing. CONCLUSION: Our findings show that even a single-word error can be deleterious to memory for text-captioned speech, especially in older adults with hearing loss. Therefore, to produce the greatest benefit to memory, it is crucial that text captions are accurate.

Text Captioning Buffers Against the Effects of Background Noise and Hearing Loss on Memory for Speech.

OBJECTIVE: Everyday speech understanding frequently occurs in perceptually demanding environments, for example, due to background noise and normal age-related hearing loss. The resulting degraded speech signals increase listening effort, which gives rise to negative downstream effects on subsequent memory and comprehension, even when speech is intelligible. In two experiments, we explored whether the presentation of realistic assistive text captioned speech offsets the negative effects of background noise and hearing impairment on multiple measures of speech memory. DESIGN: In Experiment 1, young normal-hearing adults (N = 48) listened to sentences for immediate recall and delayed recognition memory. Speech was presented in quiet or in two levels of background noise. Sentences were either presented as speech only or as text captioned speech. Thus, the experiment followed a 2 (caption vs no caption) × 3 (no noise, +7 dB signal-to-noise ratio, +3 dB signal-to-noise ratio) within-subjects design. In Experiment 2, a group of older adults (age range: 61 to 80, N = 31), with varying levels of hearing acuity completed the same experimental task as in Experiment 1. For both experiments, immediate recall, recognition memory accuracy, and recognition memory confidence were analyzed via general(ized) linear mixed-effects models. In addition, we examined individual differences as a function of hearing acuity in Experiment 2. RESULTS: In Experiment 1, we found that the presentation of realistic text-captioned speech in young normal-hearing listeners showed improved immediate recall and delayed recognition memory accuracy and confidence compared with speech alone. Moreover, text captions attenuated the negative effects of background noise on all speech memory outcomes. In Experiment 2, we replicated the same pattern of results in a sample of older adults with varying levels of hearing acuity. Moreover, we showed that the negative effects of hearing loss on speech memory in older adulthood were attenuated by the presentation of text captions. CONCLUSIONS: Collectively, these findings strongly suggest that the simultaneous presentation of text can offset the negative effects of effortful listening on speech memory. Critically, captioning benefits extended from immediate word recall to long-term sentence recognition memory, a benefit that was observed not only for older adults with hearing loss but also young normal-hearing listeners. These findings suggest that the text captioning benefit to memory is robust and has potentially wide applications for supporting speech listening in acoustically challenging environments.

Decreased proliferation of aged rat beta cells corresponds with enhanced expression of the cell cycle inhibitor p27KIP1.

BACKGROUND: Over 400 million people are diabetic. Type 1 and type 2 diabetes are characterized by decreased functional ß-cell mass and, consequently, decreased glucose-stimulated insulin secretion. A potential intervention is transplantation of ß-cell containing islets from cadaveric donors. A major impediment to greater application of this treatment is the scarcity of transplant-ready ß-cells. Therefore, inducing ß-cell proliferation ex vivo could be used to expand functional ß-cell mass prior to transplantation. Various molecular pathways are sufficient to induce proliferation of young ß-cells; however, aged ß-cells are refractory to these proliferative signals. Given that the majority of cadaveric donors fit an aged demographic, defining the mechanisms that impede aged ß-cell proliferation is imperative. RESULTS: We demonstrate that aged rat (5-month-old) ß-cells are refractory to mitogenic stimuli that otherwise induce young rat (5-week-old) ß-cell proliferation. We hypothesized that this change in proliferative capacity could be due to differences in cyclin-dependent kinase inhibitor expression. We measured levels of p16INK4a , p15INK4b , p18INK4c , p19INK4d , p21CIP1 , p27KIP1 and p57KIP2 by immunofluorescence analysis. Our data demonstrates an age-dependent increase of p27KIP1 in rat ß-cells by immunofluorescence and was validated by increased p27KIP1 protein levels by western blot analysis. Interestingly, HDAC1, which modulates the p27KIP1 promoter acetylation state, is downregulated in aged rat islets. These data demonstrate increased p27KIP1 protein levels at 5 months of age, which may be due to decreased HDAC1 mediated repression of p27KIP1 expression. SIGNIFICANCE: As the majority of transplant-ready ß-cells come from aged donors, it is imperative that we understand why aged ß-cells are refractory to mitogenic stimuli. Our findings demonstrate that increased p27KIP1 expression occurs early in ß-cell aging, which corresponds with impaired ß-cell proliferation. Furthermore, the correlation between HDAC1 and p27 levels suggests that pathways that activate HDAC1 in aged ß-cells could be leveraged to decrease p27KIP1 levels and enhance ß-cell proliferation.

The costs (and benefits) of effortful listening on context processing: A simultaneous electrophysiology, pupillometry, and behavioral study.

There is an apparent disparity between the fields of cognitive audiology and cognitive electrophysiology as to how linguistic context is used when listening to perceptually challenging speech. To gain a clearer picture of how listening effort impacts context use, we conducted a pre-registered study to simultaneously examine electrophysiological, pupillometric, and behavioral responses when listening to sentences varying in contextual constraint and acoustic challenge in the same sample. Participants (N = 44) listened to sentences that were highly constraining and completed with expected or unexpected sentence-final words ("The prisoners were planning their escape/party") or were low-constraint sentences with unexpected sentence-final words ("All day she thought about the party"). Sentences were presented either in quiet or with +3 dB SNR background noise. Pupillometry and EEG were simultaneously recorded and subsequent sentence recognition and word recall were measured. While the N400 expectancy effect was diminished by noise, suggesting impaired real-time context use, we simultaneously observed a beneficial effect of constraint on subsequent recognition memory for degraded speech. Importantly, analyses of trial-to-trial coupling between pupil dilation and N400 amplitude showed that when participants' showed increased listening effort (i.e., greater pupil dilation), there was a subsequent recovery of the N400 effect, but at the same time, higher effort was related to poorer subsequent sentence recognition and word recall. Collectively, these findings suggest divergent effects of acoustic challenge and listening effort on context use: while noise impairs the rapid use of context to facilitate lexical semantic processing in general, this negative effect is attenuated when listeners show increased effort in response to noise. However, this effort-induced reliance on context for online word processing comes at the cost of poorer subsequent memory.

A TILLING by sequencing approach to identify induced mutations in sunflower genes.

The Targeting Induced Local Lesions in Genomes (TILLING) technology is a reverse genetic strategy broadly applicable to every kind of genome and represents an attractive tool for functional genomic and agronomic applications. It consists of chemical random mutagenesis followed by high-throughput screening of point mutations in targeted genomic regions. Although multiple methods for mutation discovery in amplicons have been described, next-generation sequencing (NGS) is the tool of choice for mutation detection because it quickly allows for the analysis of a large number of amplicons. The aim of the present work was to screen a previously generated sunflower TILLING population and identify alterations in genes involved in several important and complex physiological processes. Twenty-one candidate sunflower genes were chosen as targets for the screening. The TILLING by sequencing strategy allowed us to identify multiple mutations in selected genes and we subsequently validated 16 mutations in 11 different genes through Sanger sequencing. In addition to addressing challenges posed by outcrossing, our detection and validation of mutations in multiple regulatory loci highlights the importance of this sunflower population as a genetic resource.

Coupling ecological wastewater treatment with the production of livestock feed and irrigation water provides net benefits to human health and the environment: A life cycle assessment.

Ecologically designed wastewater treatment systems (ex., Eco-Machines™) utilize a diverse ecosystem to treat wastewater to the same extent as conventional treatment, but require less energy and chemical inputs. The environmental benefits of Eco-Machines™ can be theoretically maximized by incorporating hyperaccumulating aquatic plants (ex., duckweed) to facilitate nutrient recovery and conversion into protein-rich biomass, which can then be harvested for a range of agricultural and bioenergy applications. Although it has been established that ecological wastewater treatment systems are more cost- and energy-efficient than conventional wastewater treatment systems, a systematic life cycle assessment (LCA) of an Eco-Machine™ coupled with its beneficial by-products has not been conducted. In this study, a series of LCAs were performed on different operational scenarios for a 1000 gallon per day, pilot-scale Eco-Machine™ that, in addition to producing irrigation-quality water, also produces duckweed biomass for aquaculture. The analysis revealed that Eco-Machines™ located in warm climates, which do not require a greenhouse or supplemental heating, use approximately a third of the energy and produce half of the greenhouse gas emissions compared to conventional wastewater treatment systems in similar locations, while also providing benefits to human health, ecosystem quality, climate change, and resources. In addition, increasing the growth area for duckweed using vertical farming techniques improves the overall impact of the system. This study suggests that with proper management, ecological wastewater treatment systems that upcycle nutrients and water into beneficial products can provide a net benefit to human health and the environment.

Duckweed protein supports the growth and organ development of mice: A feeding study comparison to conventional casein protein.

As global population growth and meat consumption increases, sustainable alternatives to conventional protein-rich fodder crops for livestock are needed to reduce negative environmental impacts. Duckweed, a small floating aquatic plant, can generate 5 to 10 times higher protein yields than conventional land-grown crops. Although some in vivo feeding trials with duckweed have been conducted, those measuring animal weight are limited, and those examining organ development are nonexistent. To secure broad acceptance of new protein sources, such controlled studies are critical. This study measured the food intake, growth, and final organ and adipose tissue mass of male CF-1 mice fed a semi-purified diet containing casein or diets in which 10% or 25% of the casein was replaced with duckweed protein (DWP). Proximate analysis showed that the DWP preparation used contained 39.9% protein (w/w), and contained all of the essential amino acids with Met as the limiting amino acid. The average growth rates were not significantly different among the treatment groups: 0.21 g/day; 0.24 g/day; and 0.25 g/day for the control, 10%, and 25% DWP protein diets, respectively. The daily food intake of both DWP diets was 6.5% to 8.0% higher than the control diet, but feeding efficiency did not differ among diets. The relative weight of the liver, spleen, kidneys, heart, and epidydimal fat, and colon length were not significantly different between treatment groups. The results from this study show that replacement of up to 25% dietary casein with DWP has no adverse effects on the growth rate and final organ and adipose tissue weights of laboratory mice. PRACTICAL APPLICATION: Duckweed can produce 5 to 10 times more protein per area than land-grown crops such as soybean. In this study, up to a 25% replacement of casein with duckweed protein had no observable effect on the growth or organ development of laboratory mice. Thus, duckweed has the potential to be used as a protein supplement for livestock, poultry, and fish, thereby decreasing environmental impacts from land-grown crops used for animal feed.

Cross-lagged relationships between sense of purpose in life, memory performance, and subjective memory beliefs in adulthood over a 9-year interval.

OBJECTIVES: Previous studies have found a positive association between having a sense of purpose in life and memory functioning in old age. We extend these findings by examining the relationships between sense of purpose, memory performance, and subjective memory beliefs over time in a large sample of adults in mid to later adulthood. METHOD: We used data from 3633 participants of the second and third wave of the MIDUS study. Cross-lagged panel analysis investigated the relationships between the variables at the two points, which were approximately 9 years apart, while controlling for gender, age, education, positive and negative affect, and self-rated health. RESULTS: Sense of purpose in life, memory performance, and subjective memory beliefs were all cross-sectionally related to each other at both times. Longitudinally, sense of purpose was a positive predictor of subjective memory beliefs. Memory performance and subjective memory beliefs positively predicted each other over time. Furthermore, all three variables showed correlated changes over time. Exploratory analyses suggest that the covariates of affect and self-rated health are possible mediators or confounders in respectively the relationship between subjective memory beliefs and later sense of purpose, and sense of purpose and later objective memory performance. CONCLUSION: Our findings underscore once more the relevance of sense of purpose in life as a predictor of positive late life functioning, as it is related to both performance-based and subjective cognitive outcomes. More work is needed to understand mechanisms underlying the purpose-memory association in order to develop and implement purpose interventions.

Music is similar to language in terms of working memory interference.

Some researchers theorize that musicians' greater language ability is mediated by greater working memory because music and language share the same processing resources. Prior work using working memory sentence processing dual-task paradigms have shown that holding verbal information (e.g., words) in working memory interferes with sentence processing. In contrast, visuospatial stimuli are processed in a different working memory store and should not interfere with sentence processing. We tested whether music showed similar interference to sentence processing as opposed to noninterference like visuospatial stimuli. We also compared musicians to nonmusicians to investigate whether musical training improves verbal working memory. Findings revealed that musical stimuli produced similar working memory interference as linguistic stimuli, but visuospatial stimuli did not-suggesting that music and language rely on similar working memory resources (i.e., verbal skills) that are distinct from visuospatial skills. Musicians performed more accurately on the working memory tasks, particularly for the verbal and musical working memory stimuli, supporting an association between musicianship and greater verbal working memory capacity. Future research is necessary to evaluate the role of music training as a cognitive intervention or educational strategy to enhance reading fluency.

Expansion of immature, nucleated red blood cells by transient low-dose methotrexate immune tolerance induction in mice.

Biological treatments such as enzyme-replacement therapies (ERT) can generate anti-drug antibodies (ADA), which may reduce drug efficacy and impact patient safety and consequently led to research to mitigate ADA responses. Transient low-dose methotrexate (TLD-MTX) as a prophylactic ITI regimen, when administered concurrently with ERT, induces long-lived reduction of ADA to recombinant human alglucosidase alfa (rhGAA) in mice. In current clinical practice, a prophylactic ITI protocol that includes TLD-MTX, rituximab and intravenous immunoglobulin (optional), successfully induced lasting control of ADA to rhGAA in high-risk, cross-reactive immunological material (CRIM)-negative infantile-onset Pompe disease (IOPD) patients. More recently, evaluation of TLD-MTX demonstrated benefit in CRIM-positive IOPD patients. To more clearly understand the mechanism for the effectiveness of TLD-MTX, non-targeted transcriptional and proteomic screens were conducted and revealed up-regulation of erythropoiesis signatures. Confirmatory studies showed transiently larger spleens by weight, increased spleen cellularity and that following an initial reduction of mature red blood cells (RBCs) in the bone marrow and blood, a significant expansion of Ter-119+ CD71+ immature RBCs was observed in spleen and blood of mice. Histology sections revealed increased nucleated cells, including hematopoietic precursors, in the splenic red pulp of these mice. This study demonstrated that TLD-MTX induced a transient reduction of mature RBCs in the blood and immature RBCs in the bone marrow followed by significant enrichment of immature, nucleated RBCs in the spleen and blood during the time of immune tolerance induction, which suggested modulation of erythropoiesis may be associated with the induction of immune tolerance to rhGAA.