Record linkage is an important tool for epidemiologists and health planners. Record linkage studies will generally contain some level of residual record linkage error, where individual records are either incorrectly marked as belonging to the same individual, or incorrectly marked as belonging to separate individuals. A key question is whether errors in linkage quality are distributed evenly throughout the population, or whether certain subgroups will exhibit higher rates of error. Previous investigations of this issue have typically compared linked and un-linked records, which can conflate bias caused by record linkage error, with bias caused by missing records (data capture errors).Four large administrative datasets were individually de-duplicated, with results compared to an available ‘gold-standard’ benchmark, allowing us to avoid methodological issues with comparing linked and un-linked records. Results were compared by gender, age, geographic remoteness  and socioeconomic status.Results varied between datasets, and by sociodemographic characteristic. The most consistent findings were worse linkage quality for younger individuals  and worse linkage quality for those living in remote areas (seen in three of four datasets). The linkage quality within sociodemographic categories varied between datasets, with the associations with linkage error reversed across different datasets due to quirks of the specific data collection mechanisms and data sharing practices.These results suggest caution should be taken both when linking younger individuals and those in remote areas, and when analysing linked data from these subgroups. Further research is required to determine the ramifications of worse linkage quality in these subpopulations on research outcomes.The online version of this article (10.1186/s12913-018-3495-x) contains supplementary material, which is available to authorized users. Record linkage is a set of methodologies designed to bring together information relating to the same person from within or across datasets . This teStudies using linked data will generally contain linkage error. There are two types of record linkage errors; false positives, where two records are designated as belonging to the same individual when in truth they do not; and false negatives, where two records are designated as belonging to different individuals when in truth they belong to the same individual. Linkage error can occur due to both legitimate changes in a person’s particulars (i.e. change of address) or due to data fields being missing or in error (i.e. poor recording practices in the data collection in question). Researchers using linked data will generally not have the personally identifying information made available to them for privacy reasons . This meA number of studies have illustrated how poor linkage quality can cause bias and distort results. A study of the effect of linkage methods (two deterministic strategies and one probabilistic strategy) on mortality rate estimates showed relative differences of up to 25% between the true estimate and that found through record linkage . In a stA key question is whether errors in linkage quality are distributed evenly across a study population. In other words, do the linked records of people from certain subgroups  contain a greater proportion of errors? If a certain subgroup was found to have lower linkage quality, this would suggest research results might be systematically biased against this group.Thi), which will make their data harder to link. Different ethnic groups may also display different rates of identifier reporting; for instance, in the United States, African American adults are less likely to report social security number, a highly identifying attribute, making their data harder to link [There are a number of plausible reasons why linkage quality may vary between subgroups. Key causes of linkage error are changing or incorrect identifiers . Given t to link . Recordi to link . Differe to link . A recen to link , indicatA number of studies have explored the relationship between linkage quality and sociodemographic factors, although typically as part of a wider study. A review by Bohensky et al.  found diTwo key issues arise when using this research design to explore bias caused by poor linkage quality. Firstly, the approach focusses only on false negative errors (records which incorrectly did not find a match) and does not consider the issue of false positive errors, an equally important type of linkage error. By only reporting on one of the two error types, we cannot gain an accurate understanding of the relationship between linkage quality and sociodemographic factors.A second and more fundamental problem in comparing sociodemographic subgroups using this methodology is that we often cannot distinguish whether an individual is unmatched due to linkage quality error, or due to the fact that these matched records do not exist. In many of these cases, differences in linkage bias arise from differences in subgroup data capture. Such differences can be expected to be highly dataset dependent. For example, in a recent US study linking a clinical surgical registry to US Medicare inpatient claims, the unmatched individuals in the clinical surgical registry were more likely to be those who did not have coverage under Medicare, rather than individual whose correct match could not be found . ConsequIn this paper, we attempt to address these methodological shortcomings through the use of an alternate research design. Four large, real-world Australian administrative datasets were de-duplicated, with results and compared to an available ‘truth-set’, allowing comparison of both false positive and false negative errors.n = 6,772,949), ten years of New South Wales (NSW) hospital admissions data , three years of NSW public emergency department (ED) presentation data  and three years South Australian (SA) ED presentation data . Each dataset contained errors typical of administrative data, including missing and incorrect identifiers, and identifiers that change over time. Each dataset had previously been de-duplicated  to a high quality by jurisdictional linkage units . These linkage units utilised a variety of deduplication methods including probabilistic record linkage, intensive manual review of created links and quality assurance procedures to analyse and review potential errors [Each of the four separate administrative health datasets used in the evaluation contained multiple event-based records per person. The datasets comprised: ten years of Western Australian (WA) hospital admission data , geographical region and socioeconomic status. Year of birth was split into three categories; those born prior to 1950, those born from 1950 to 1979, and those born from 1980 onwards . Indices of geographic remoteness  were usA de-duplication linkage was conducted on each of the four datasets, using the record linkage method described above, resulting in a series of matched record-pairs. Linkage quality was calculated for each of the sociodemographic characteristics by ignoring those record-pairs that did not include at least one record with that sociodemographic category. For example, linkage quality for individuals for remote areas was calculated by evaluating the linkage quality on all pairs of records of which at least one record was from a remote area. Pair-based linkage quality was calculated directly on these record-pairs. Additionally, the metrics were calculated for a range of threshold scores to investigate how linkage bias may change as the threshold is either increased or decreased.As clinical content data for each dataset was not available, statistics on the incidence of hospital encounters  were calculated for each socio-demographic- category, with results compared against results from the gold-standard benchmark.The number of records within each sociodemographic category for each dataset is shown in Table Overall, the linkage quality achieved in the deduplication of each dataset was very high. Linkage results at the optimal threshold  are shown in Table male = 0.981, recall female = 0.962). There was an identifiable effect of age on linkage quality, with persons born after 1980 having a lower linkage quality  for all four datasets, as compared to those born before 1950 . The effect of geographic remoteness on linkage quality was not as clear. In the NSW emergency, SA emergency and WA hospital datasets, records of persons in remote areas had lower recall compared with those in major cities  was only noticeably greater for those in remote areas in the WA hospital dataset . For socioeconomic status, the effect on linkage quality, in terms of precision and recall, was even less clear. In the WA hospital dataset, precision and recall both generally decreased as socioeconomic status decreased, with those in the upper quintiles having the highest linkage quality. For the NSW hospital dataset, however, the effect was the opposite, with precision and recall generally decreasing as socioeconomic status increased. Results for the NSW emergency dataset showed little difference in precision and recall between socioeconomic quintiles, while the results for SA emergency data did not show any clear trend.Variations in linkage quality by sociodemographic category for each of the four datasets, calculated at the optimal threshold score, are shown in Figs. We further determined the optimal threshold score for each particular sociodemographic factor . However, this resulted in no substantial change in linkage quality .Comparisons of incidence rates for each dataset and sociodemographic category are shown in Table There was some evidence that linkage quality varied across and within different sociodemographic categories. While some differences were found for gender and socioeconomic status, these results occurred only in particular datasets. The finding of poorer linkage quality for those in remote areas was more consistent, appearing in three of the four datasets. The most reliable finding was decreased linkage quality for younger individuals as compared to older individuals, found in all four datasets.There are a number of reasons why poorer linkage quality may be expected in younger individuals and individuals who live in more remote areas. Younger individuals are more mobile and so change address more often . Birth rThe results found in this study suggests differences in linkage error across sociodemographic categories are highly dataset dependent. Specific quirks in recording standards in some data collections account for some of these findings. For instance, the NSW hospital admissions dataset did not contain name information for individuals attending private hospitals (containing only date of birth and address information). This is likely the reason for the finding in this dataset that linkage quality decreases as individuals have higher socioeconomic status, since those with higher socioeconomic status are more likely to attend private hospitals, and so have missing name data. It is quite possible that other findings in our dataset also reflect specific recording anomalies that we are not aware of.The differences found in linkage quality were generally small, with a few larger differences  found in remote areas. These differences in linkage quality had little notable effect on incidence rates. The effect of these errors on other derived clinical indicators is an important area of further study.The use of subgroup-specific threshold settings made little difference to overall linkage quality, and based on these results cannot be recommended. Other published techniques such as the use of graph theory methods  or alterA key strength of our study was the use of validated, real world datasets where the ‘answer’ in relation to linkage results is known. This allowed us to assess both false positive and false negative errors in record linkage. The use of a gold standard benchmark avoids the difficulty associated with determining whether non-matched records are the result of linkage error or some other reason (i.e. data capture error), a key weakness in many previously published studies. It should be noted that while the gold-standard results used in this study were of very high quality due to extensive clerical review and quality assurance, errors may still exist within the gold-standard results.This study utilised a ‘default’ probabilistic linkage strategy, which we consider a relatively standard approach, and which achieves high quality results. As such, the level of error found in this study we consider to be small. While we could deliberately degrade the linkage strategy to reduce linkage quality and therefore amplify the level of bias in the results, we would risk introducing bias that would not typically be found in practice.Information on additional subpopulations that may have higher risk of lower linkage quality, such as Indigenous Australians, immigrant groups, those with poorer health status, and those with mental health conditions, was not available but further research in these areas is warranted. Our study used structured and defined administrative datasets, with high quality data collection standards; as a result, overall linkage quality was very high. Data collections with overall poorer quality may produce magnified or alternate results to those found in this study. Interactions are likely to exist between several variables that influence linkage quality. For instance, Indigenous Australians make up a greater proportion of the population in remote areas as compared to major cities and are more likely to be from lower socioeconomic status areas. In addition, regional and especially remote areas generally have lower socioeconomic status as compared to major cities. Interaction effects such as these were not explored in this study. It is also not clear whether the number of existing records per person influences the difficulty of linking data related to that individual; this may interact with the tested sociodemographic categories, particularly those related to age.Our results suggest linkage quality in those younger and those living in remote areas may be lower, as a result, caution should be taken when analysing differences in linked Australian hospital data by age or geographic remoteness. Further research is required to determine the ramifications of these results for researchers utilising linked data.Additional file 1:Table S1. Proportion of missing values in each dataset, stratified by sociodemographic variable. (DOCX 21 kb)


Massive Open Online Courses (MOOCs) have the potential to democratize education by providing learners with access to high-quality free online courses. However, evidence supporting this democratization across countries is limited. We explored the question of MOOC democratization by conducting cross-national comparisons of gender differences in the enrollment in and completion of science, technology, engineering, and mathematics (STEM) MOOCs. We found that while females were less likely than males to enroll in STEM MOOCs, they were equally likely to complete them. Further, a higher probability to enroll in STEM MOOCs and smaller gender gaps in STEM MOOC enrollment and completion were found in less gender-equal and less economically developed countries. Massive Open Online Courses (MOOCs) have attracted tens of millions of learners around the world. Theoretically, anyone with an Internet connection is able to freely access these online courses, which are often provided by professors from elite universities. Similar to previous technological advancements in broadcast media, such as radio and television, MOOCs were expected to transform education by providing learning opportunities for those who otherwise would not have access to them . The groHowever, the optimistic expectation that MOOCs will promote educational equity has been dampened by studies describing the demographics of individuals who enroll in and complete MOOCs –5. StatiIn addition to the critique that MOOCs do not reach disadvantaged individuals, concerns have been voiced about whether MOOCs increase the participation of females in STEM fields . Gender Therefore, this paper aims to explore the question of MOOC global democratization by examining the cross-national differences of females’ enrollment in and completion of STEM MOOCs and exploring whether and how the size of the gender gap in STEM MOOC enrollment and completion varies by country-level characteristics . We specifically examine enrollment and completion separately because MOOCs are notorious for having very low completion rates . AdditioOur analytical framework is guided by the Eccles’ Expectancy-Value Model of Achievement-Related Choices –13. Thisth-grade science and math achievement [One strand of previous empirical studies suggests that gender-equal cultures are associated with higher levels of female representation in STEM choices and smaller gender differences in STEM performance. Van Langen and Dekkers found that females from countries that were more gender conscious and advanced in females’ emancipation  considered STEM courses more attractive . In termievement . McDanieievement . If thisAnother strand of empirical studies found that economic development is negatively associated with females’ participation in STEM field . BradleyWhen it comes to developing countries, lack of access to high-quality STEM courses has been one of the factors that has hindered students’ enrollment in traditional STEM fields ; this maThe male-favoring gender differences in the use of computers, mobile devices, and the Internet still exist in most parts of the world, especially in developing countries –31. For Previous studies show that females perform as well as, if not better than, males in online learning settings. For instance, Yukselturk and colleagues did not find significant differences in programming achievement with respect to gender in a self-regulated online learning environment in Turkey . Wladis In summary, previous studies suggest possible gender differences in STEM MOOC enrollment and completion as well as varying gender differences associated with country-level characteristics . We ask the following research questions: 1. What are the directions of gender differences in STEM MOOC enrollment and completion? 2. How do country-level characteristics  moderate the relationship between gender and the enrollment in and completion of STEM MOOCs? If MOOCs were to hold the promise to democratize and empower the traditionally disadvantaged females, the potential gains would be much larger in less gender-egalitarian and less economically developed countries.To address our research questions, we used the HarvardX-MITx Person-Course de-identified dataset from the 2012–2013 academic year  , which included 16 HarvardX and MITx courses on the edX platform. This dataset is the most comprehensive publicly available dataset on MOOCs. In total, 13 MOOCs were labeled as STEM MOOCs and three MOOCs were labeled as non-STEM. We used the Gender Gap Index (GGI) created by the World Economic Forum to measure a country’s gender equality level . GGI refAs GGI does not reflect a country’s development level, we included GDP per capita (2012) to measure a country’s economic development level the year the data were collected  and usedTo answer our research questions on the directions of gender differences and how country-level characteristics  may moderate the relationship between gender and the enrollment in and completion of STEM MOOCs, we conducted a series of multilevel logistic regression models using R lme4 package to account for the nesting of an individual within a country. The multilevel framework is an appropriate method for addressing our research questions because it takes into account the nesting of individuals within groups (in our case within countries) . These mLevel-1 equationβk0), the main effect of being female , the main effect of age (βk2Ageik), the main effect of education (βk3Educationik), and a residual for the learner (eik). The level-two equation allows for random variations in intercepts between countries where the country-level intercepts (βk0) are comprised of a grand mean (γ00), a fixed effect for GGI (γ01GGIk), and random deviations in intercepts between countries (uk0). Additionally, a random effect for gender was included such that the association between gender and the outcome was allowed to differ between countries as denoted by uk1. For the models examining the relation between GDP per capita and STEM MOOC enrollment and completion, GDP per capita instead of GGI is used in the above-mentioned equations.Level-2 equationWe tested all of our models for the inclusion of random slopes and random intercepts. Using the likelihood ratio test, we found that random slope models performed significantly better when a random slope was included for female. Therefore we report results from models where slopes were able to vary randomly for female. To examine the degree to which learners from different countries differ in their propensity to choose and complete STEM MOOCs, we calculated the intraclass correlation coefficient (ICC) to determine if there was sufficient country-level variance to model . The ICCWhen it comes to completion of STEM MOOCs , only 1,This study complements previous work investigating the democratization of MOOCs in the United States , by suggConsidering that females are generally less likely than males to enroll in STEM MOOCs and only consisted of 24% of STEM MOOC learners, more studies should be conducted to explore the factors influencing females’ enrollment in STEM MOOCs. Currently, it is unclear whether females’ underrepresentation in STEM MOOC enrollment is due to the lack of access to the Internet , gender The smaller male-favoring gender gaps in STEM MOOC enrollment and completion in less gender-egalitarian and less economically developed countries indicate that MOOCs might offer broad country-level social benefits for less socially and economically developed countries. Free and easy access to MOOCs in developing countries allows females to try out STEM courses that are not easily available to them in their local communities. This finding also aligns with the educational-gender-equality paradox found by Stoet and Geary, i.e., the gender differences in the magnitude of relative academic strengths and pursuit of STEM degrees rose with increases in national gender equality .These phenomena can be explained by the expectancy value theory . The lifThis study has certain limitations. First, the fact that the pseudo-R squareds are small (see Tables Secondly, the datasets were collected in 2012–2013 and thus do not reflect more recent trends in MOOC enrollment and completion. This is due to the nature of MOOC data that has been made publicly available so far. As additional MOOC data becomes available, future research should investigate whether and how the patterns of results identified in our study might change.


Tryptophan is one of the eight essential amino acids that must be obtained from the diet. Interestingly, tryptophan is the least abundant amino acid in most proteins, a large portion of cellular tryptophan is converted into metabolites of the serotonin and kynurenine pathways. In a recent study, , we discovered that colon cancer cells display greater uptake and processing of tryptophan than normal colonic cells and tissues. This process is mediated by the oncogenic transcription factor MYC that promotes the expression of the tryptophan importers SLC1A5 and SLC7A5 and the tryptophan metabolizing enzyme AFMID. The metabolism of tryptophan in colon cancer cells generates kynurenine, a biologically active metabolite necessary to maintain continuous cell proliferation. Our results indicate that kynurenine functions as an oncometabolite, at least in part, by activating the transcription factor AHR, which then regulates growth promoting genes in cancer cells. We propose that blocking kynurenine production or activity can be an efficient approach to specifically limit the growth of colon cancer cells. Here, we describe our findings and new questions for future studies targeted at understanding AHR-independent function of kynurenine, as well as interfering with the enzyme AFMID as a new strategy to target the kynurenine pathway. The kynurenine pathway is aberrantly activated in cancer cells in a process that we discovered to be regulated by the activity of the oncogene MYC.Tryptophan can be utilized in three ways intracellularly: it can be incorporated into newly synthesized proteins, it can be processed by the serotonin pathway to give rise to serotonin and melatonin, and it can be processed by the kynurenine pathway to generate multiple biologically active catabolites . Kynurenine can be converted into kynurenic acid through the activity of kynurenine aminotransferase (KAT), into 3-hydroxy kynurenine by kynurenine 3-monooxygenase (KMO) or into anthranilic acid by kynureninase (KYNU). 3-hydroxy kynurenine is further metabolized into cinnabarinic acid, picolinic acid, or quinolinic acid, which gives rise to nicotinamide adenine dinucleotide (NAD), a co-enzyme that mediates redox reactions in a number of metabolic pathways, including glycolysis. While the liver contains all the enzymes necessary to metabolize tryptophan via the kynurenine pathway to generate NAD, the expression of specific enzymes by other tissues determine which tryptophan metabolites those tissues generate.In the first step of the kynurenine pathway, tryptophan is metabolized by one of the three functionally equivalent enzymes: indoleamine 2,3-dioxygenase1 (IDO1), indoleamine 2,3-dioxygenase2 (IDO2), or tryptophan 2,3-dioxygenase 2 (TDO2) to produce N-formyl kynurenine, which is then converted into kynurenine by the activity of arylformamidase (AFMID) We found that samples of colon cancer have higher kynurenine levels than the respective matched healthy colon samples. This elevation in kynurenine correlates with the expression of the enzymes TDO2, IDO1, and AFMID in the same patient samples. Interestingly, TCGA analysis demonstrated that most colon cancer samples have greater expression of the tryptophan transporters SLC1A5 and SLC7A5 and the enzyme AFMID than the normal tissues from the same patients. The levels of TDO2 and IDO1 are elevated in fewer patients. Importantly, enzymes involved in further degrading kynurenine into downstream catabolites are not upregulated in the colon cancer samples, thus suggesting that kynurenine is a predominant metabolite of this pathway in colon cancer cells. Indeed, our results show that kynurenine is present at equimolar concentrations with tryptophan in colon cancer samples. All other catabolites are present at levels orders of magnitude lower. These results led to the hypothesis that kynurenine is biologically active in colon cancer.Extensive research has established that tumor-produced kynurenine is exported into the tumor microenvironment, where it causes T-cell inactivation. This leads to immune evasion and survival of cancer cells. In addition to eliciting a paracrine effect on T-cells, our work, together with a growing body of data from others, established that kynurenine promotes growth of cancer cells by cell-autonomous mechanisms. Molecularly, the most well-understood function of kynurenine is as a ligand for the transcription factor aryl hydrocarbon receptor (AHR). Our lab has previously shown that AHR expression is elevated in colon tumors where it drives the expression of genes necessary for cell growth. Our recent study demonstrated that kynurenine is co-induced with AHR in the same tumors, thus indicating that the kynurenine-AHR pathway is active in colon cancer cells.Our work demonstrated that blocking the conversion of tryptophan into kynurenine is an effective strategy to specifically limit the proliferation of colon cancer cells and transformed colonic organoids. Interestingly, blocking the binding of kynurenine to AHR also reduces the proliferation of colon cancer cells, however, less dramatically than inhibiting kynurenine production. Our results suggest that AHR-independent functions of kynurenine may exist. Future studies comparing cellular functions of kynurenine in AHR-deficient and wild-type cells will provide information on novel and potentially critical functions of kynurenine as an oncometabolite.13C-tryptophan and mass spectrometry, we found that the conversion of tryptophan into kynurenine was greater in MYC-driven colon cancer cells than normal primary colonic epithelial cells.The transcription factor MYC is a potent oncogene, which is upregulated in the majority of human tumors. MYC promotes cellular transformation by driving metabolic reprograming that leads to biomass accumulation and cellular proliferation. Using a combination of approaches, we discovered that MYC-transformed cells exhibit an increase in tryptophan uptake and processing by the kynurenine pathway. We found that MYC promotes the import of tryptophan into colon cancer cells by transcriptionally driving the expression of SLC7A5 and SLC1A5, which are capable of transporting tryptophan. MYC also induces the expression of the enzyme arylformamidase (AFMID) in cultured colon cancer cells. Using Our study demonstrates for the first time that a specific oncogenic hit directly drives kynurenine production and that transformed cells require kynurenine for growth. An important question that remains unanswered is whether or not kynurenine is necessary for tumor initiation and whether altered tryptophan uptake and metabolism precedes the formation of cancerous lesions. Because MYC was shown to be indispensable for colon cancer initiation in animal models and because MYC expression is elevated in almost all colon cancers samples, we predict that kynurenine levels will be globally elevated in colon cancer patients. Sensitive methods to detect kynurenine in the plasma could become an efficient non-invasive approach to identify patients with increased risk of colon cancer.in vivo. Nonetheless, additional studies are necessary to better define the contribution of AFMID to cellular growth and to determine whether this enzyme can be targeted to limit kynurenine production and prevent cancer cell growth without affecting the integrity of normal tissues.The observation that IDO1 is elevated in several tumors spurred the development of inhibitors of IDO1 with the goal of inhibiting kynurenine production to allow the clearance of cancer cells by the patient's own T-cells. Unfortunately, clinical trials using IDO1 inhibitors to treat various types of cancer have been unsuccessful, potentially due to redundant functions played by IDO2 and TDO2. Our results regarding the importance of AFMID in the kynurenine pathway in colon cancer open the exciting possibility that AFMID may provide a better target to abrogate kynurenine production in vivo will lead to the identification of tumors that are dependent on tryptophan and kynurenine, thus defining a patient population that have the potential of responding to inhibition of the kynurenine pathway.Future studies targeted at defining AHR-independent roles of kynurenine and its catabolites could be key to fully comprehend the effects of the kynurenine pathway in cancer. One or more tryptophan catabolites could provide diagnostics or prognostics tools for colon cancer and other diseases. Implementing sensitive methods to quantify tryptophan uptake and processing


Globally, asthma is one of the most common chronic conditions that affect individuals of all ages. When poorly controlled, it negatively impacts patient's ability to enjoy life and work. At the population level, effective use of recommended strategies in children and adults can reduce symptom burden, improve quality of life and significantly reduce the risk of exacerbation, decline of lung function and asthma-related death. Inhaled corticosteroid as the initial maintenance therapy, ideally started within 2 years of symptom onset, is highly effective in both children and adults and across various degrees of asthma severity. If asthma is not controlled, the choice of subsequent add-on therapies differs between children and adults. Evidence supporting pharmacological approach to asthma management, especially for those with more severe disease, is more robust in adults compared to children. This is, in part, due to various challenges in the diagnosis of asthma, in the recruitment into clinical trials and in the lack of objective outcomes in children, especially those in the preschool age group. Nevertheless, where evidence is emerging for younger children, it seems to mirror the observations in adults. Clinicians need to develop strategies to implement guideline-based recommendations while taking into consideration individual variations in asthma clinical phenotypes, pathophysiology and treatment responses at different ages. Asthma is a chronic inflammatory disease of the airways with typical symptoms of wheezing, breathlessness and cough and variable airflow obstruction. The WHO estimates that some 235 million people currently suffer from asthma  and it iControl of asthma symptoms, reduction of future risk in terms of asthma attacks, and prevention of decline in lung function are recognized as the key goals of asthma management . These gThere is increasing recognition of different clinical and patho-physiological patterns of asthma (‘phenotypes’) in both children and adults.The most striking asthma phenotype is found in young children who present with wheezing attacks associated with viral infection, particularly rhinovirus infection, often with no symptoms between attacks. For many of these children, the wheezing attacks stop in later childhood . In oldeIn adults, the pattern of airway inflammation is more diverse and the clinical presentation is often clouded by co-existing comorbidities especially in those with severe asthma , 9. CurrThere are some patients, both adult and children, with “discordant” disease who suffer substantial symptom burden with little evidence of eosinophilic inflammation or those with high level of inflammation but few symptoms . HoweverThis review summarizes evidence about differences in the approaches to asthma treatments in adults and children as currently recommended in commonly used asthma guidelines , 13 Tab.For patients of all ages, as needed short acting beta2 agonist (SABA) reliever therapy is highly effective for rapid relief of asthma symptoms. SABA as the sole treatment is now only recommended for those with the mild and intermittent symptoms , no history of asthma attacks in the previous year and normal lung function.Historically, there has been a perception that patients with intermittent symptoms are not at risk of asthma attacks, a view increasingly challenged. Evidence from adult studies showed that airways inflammation occurs at a very early stage of the disease even in patients with intermittent asthma, albeit at a lower level than in those with persistent asthma , 15. FurThis has led widely used international guidelines , 13 to uRegular low dose ICS significantly improves lung function, quality of life and reduces asthma exacerbations in both adults and children with mild persistent asthma , 18. O'BThe greatest benefits of ICS in adults and children older than 5 years old have been achieved when ICS therapy was started within 2 years of symptom onset , 22; thiOne important difference in children compared with adults is a persistent concern about the impact of regular ICS in children on linear growth. As an example, in the START study Pauwels et al. reported that children aged 5–15years treated with budesonide showed reduced growth especially in the first year of treatment . HoweverThe evidence on linear growth in children treated with ICS has recently been updated to take account of newer inhaled steroid molecules. The regular use of ICS at low or medium daily doses was found to be associated with statistically significant growth suppression during a 1-year treatment period in children with mild to moderate persistent asthma. The mean growth reduction was 0.48 cm/year in linear growth velocity and 0.61 cm change from baseline height during a one year treatment period. ICS-induced growth suppression appears to be maximal during the first year of treatment and less pronounced in subsequent years and appears to be more strongly associated with ICS molecule than with the device or dose in the low to medium dose range . A seconThere is also strong and consistent evidence to support the use of daily ICS for preventing exacerbations in preschool children with recurrent wheeze, especially in those with persistent asthma symptoms . The effThe evidence about growth suppression in pre-school children is limited. Nevertheless, because of concerns about side effects, an important question is whether ICS therapy can be targeted to those children most likely to respond? One recent study in children requiring step 2 treatment showed that while individual treatment responses were phenotypically diverse, children with aeroallergen sensitization and increased blood eosinophil counts responded best to a daily ICS as opposed to a leukotriene receptor antagonist (LTRA) or as needed-ICS. Daily ICS was associated with more asthma control days and fewer exacerbation . HoweverFor steroid-naïve adults and adolescents with mild persistent asthma, ICS/LABA works faster in achieving GINA-defined good asthma control compared to ICS alone. However, there is little difference in exacerbation rate between the two therapies. In practice, the additional cost for ICS/LABA compared to low dose ICS may be an important consideration for the individual patient . Data asRegular use of ICS raises concerns from patients and clinicians about adherence and steroid side effects. Poor adherence to ICS potentially results in patients relying on SABAs to control symptoms, possibly resulting in overuse.Recently, it was shown that adults and adolescents with mild asthma using as-needed combination ICS and fast acting LABA had better asthma symptom control measured by an electronic diary compared to as-needed SABA . HoweverThere is less evidence about the use of as needed ICS treatment in children. One study in children from 5 years upwards with mild well-controlled asthma stepping down from daily ICS found ICS and SABAs as needed more effective at reducing attacks than SABA use alone . Liner gIn children under 5 years, the most common asthma phenotype is intermittent viral triggered wheezing attacks with no interval symptoms. In this group, intermittent ICS, usually as high-dose ICS at the first sign of an URTI for 7 to 10 days led to a 35% reduction in severe attacks . IntermiBecause of concerns about ICS side effects and difficulties using inhaled therapies in young children, oral montelukast has been widely prescribed as an alternative to regular ICS. While early studies showed it to be effective, the most recent review found no evidence of benefit from the use of montelukast, continuously or intermittently on the number of wheezing episodes, unscheduled medical attendance, or oral corticosteroid use in preschool children with recurrent wheeze . There iFor adults and adolescents with suboptimal symptom control or more than 1 exacerbation in the previous year despite treatment with low dose ICS, guidelines recommend low dose ICS/LABA as maintenance therapy plus SABA or ICS/formoterol as single inhaler therapy , 13. In 1), proportion of symptom-free days  on ICS maintenance therapy to receive a personalized management plan that included a temporary quadrupling of ICS when asthma control started to deteriorate compared to remaining on their usual ICS dose  with mild to moderate asthma already on low dose ICS therapy and reported no difference in rates of exacerbation in those treated with quintupled dose of ICS compared with their usual ICS dose at the earliest sign of asthma deterioration  found montelukast had been stopped in 16% of children because of neuropsychiatric effects , mostly within 2 weeks of starting therapy (Neuropsychiatric side effects have been reported as not uncommon in young children started on montelukast. One study ( therapy . Long te therapy .Allergen immunotherapy (AIT) is still the only-disease modifying treatment strategy for IgE-mediated allergic disease . Studies1 is > 70% predicted  for children with asthma. Although there is weak evidence that theophyllines were better than placebo, they are no longer used because ICS were shown to be more effective at improving symptoms and reducing asthma attacks . When loTheophyllines have adverse effects including headaches and nausea if therapeutic concentrations are exceeded. There are also significant interactions with some commonly used drugs which inhibit theophylline clearance e.g., erythromycin which can result in increased theophylline levels and resulting toxicity.The great majority of adults with severe asthma not responding to high dose treatments are “difficult-to-treat” because of comorbidities and risk factors that mimic or worsen asthma control , 87 and Poor adherence with treatment is a particularly important cause of difficult to treat asthma in both adults and children. Improving adherence is difficult. A variety of interventions have been shown to lead to improvements including adherence education, the use of electronic trackers or reminders, simplified drug regimens and school-based directly observed therapy. However, because of uncertain and inconsistent impact on clinical outcomes such as quality of life and asthma control the clinical relevance of the improvements has been less clear with many studies affected by concerns about risk of bias and inconsistency . The mosA number of add-on options are available for those with severe therapy resistant asthma. But prior to the use of these therapies, it is important to follow a systematic approach in the assessment and management of “difficult-to-treat” severe asthma—to confirm diagnosis, address poor adherence and to identify and manage comorbidities and risk factors , 94.The following add-on options are best reserved for well-phenotyped patients with “severe treatment-refractory” asthma. The bulk of the evidence for their use at present is in adults and adolescents.Omalizumab can be used for adults and children over 6 years of age with inadequately controlled severe allergic asthma despite optimized therapies , 13. TheIn addition, omalizumab allows for reduction or withdrawal of inhaled corticosteroid use but the latter option must be considered with caution . In chilIn clinical use in both adults and children omalizumab has proved safe with few serious adverse effects .Newer therapies targeted at IL-5  or the IL-5 receptor  are effective for adolescents and adults with severe eosinophilic asthma at high risk of exacerbations or with high symptom burden despite high dose ICS and another maintenance therapy . The effRandomized trials for all three anti-IL-5 therapies recruited patients over 12 years and included a few adolescents; studies using mepolizumab in children age between 6 and 11yr are underway. The EMA has recently approved mepolizumab for use in children 6–17years but this is based on an extrapolation of data from the efficacy and safety data from the Phase III studies in the mepolizumab severe asthma development programme for patients 12 and over.Macrolides have antibacterial, antiviral and immunomodulatory effects and are shown to be effective in different asthma phenotypes . Adults At present, there is no evidence that regular treatment with macrolides improves asthma control in children. Intermittent use of azithromycin in preschool children at the time of asthma attacks has been investigated. One study found that Azithromycin shortened the duration of episodes of asthma-like symptoms in young children aged 1–3years ; in a seBronchial thermoplasty is a non-pharmacological, endoscopic treatment for subjects aged ≥18 years with severe persistent asthma that is not well-controlled with ICS and LABA. Bronchial thermoplasty provides lower rates of exacerbations and modest improvements in quality of life but no difference in asthma control scores in patients with moderate to severe asthma –117. TheChromones have favorable safety profile but low clinical efficacy compared to ICS in adults and children . The mosPharmacological management of asthma is based on continuous cycle of assessment, treatment and review to allow up or down titration of maintenance therapies to maximize patient outcomes using minimal treatment at various stage of the disease , 13.Most guidelines recommend a change in management based on measures of symptom control with or without other risk factors such as compromised lung function or a history of exacerbations. Symptom based approaches are essentially all that is available in young children because of the fact they cannot co-operate with standard lung function tests.For many patients in primary care, symptom control is a good guide to reduced risk of exacerbations. However, it is important to be mindful that in some patients, there may be discordance between responses in symptom control and asthma attacks. In preschool children, particularly, many children will have severe attacks of wheezing but no symptoms in between attacks.Airways inflammation in asthma can be predominantly eosinophilic or non-eosinophilic. While ICS are the major preventer treatment to control symptoms, ICS are more effective in reducing symptoms in patients with eosinophilic inflammation than in those with neutrophilic inflammation . There h1, asthma control test score, asthma quality of life, beta agonist use). There was also no difference in the final ICS use in either adults or children for either strategy (The most up-to-date synthesis of the evidence concluded that children and adults randomized to either eosinophilic marker strategy were significantly less likely to experience an exacerbation during the follow-up period (4.5–24months). The exacerbation rate was also lower in adults with either strategy compared to controls, but not in children. For both strategies in adults and children, there was no difference for all secondary outcomes (FEVstrategy .Exacerbations are one, albeit important, asthma outcome; other outcomes such as symptom control and lung function also need consideration. Why there is discrepancy between exacerbations and other asthma outcomes is not understood but it has been noted in other studies involving the newer monoclonal drugs targeted at eosinophilic allergic pathways such as mepolizumab .Currently, sputum induction is restricted to laboratories and clinics with specific expertise. It is technically demanding and time consuming and not always successful, particularly in younger children. Universal use of FeNO would be a substantial extra cost if used for all asthma patients and there is a yet no evidence-based algorithm on how to adjust treatment based on FeNO levels. Such an approach is most likely to benefit those with frequent asthma exacerbations.In studies limited to non-smoking adults, FeNO >50ppb was predictive of good short-term response to ICS . HoweverThe evidence base for the management of children with asthma, particularly young children, is often quite limited and has been compounded by a number of problems. Children under the age of 5–6years are usually not able to co-operate with lung function test and as result objective outcomes are commonly not available. Trials of treatment are more problematic without objective outcomes. New drugs are usually not tested in children until they have been extensively tested in adult patients. Recruiting and retaining children and their parents into randomized studies is difficult and as a result trials are often more limited in scale and duration. The consequence is that the evidence base for asthma treatments is often much smaller than available for adults. However, when an evidence base does emerge it is surprising how often it mirrors the that from adult studies. The value of ICS in preventing asthma exacerbations in young children would be an obvious example.Asthma Guidelines summarize “population level” evidence and provide broad and generalized recommendations about asthma management , 13. HowDespite publication of many evidence-based guidelines and the availability of effective therapies, there is widespread concern that asthma control in adults and children often remains poor and that asthma attacks and even deaths from asthma are not improving , 124. ThAsthma can significantly impact on all facets of life for patients across all age groups. Effective management strategies are broadly summarized by local and international guidelines. Overall, the evidence for pharmacological approach are more extensive and more robust for adults than that for younger children. For milder disease, the use of ICS as the initial maintenance therapy and SABA as needed appears universally effective for children, adolescents and adults. However, the preferred choice of subsequent add-on therapies differs and the evidence base for advanced therapeutic options is mostly based on studies in adolescents and adults. Clinicians are currently challenged with the need to develop management strategies that best caters for individual differences in asthma presentation and management. Accounting for differences in pathophysiological mechanisms, asthma phenotypes and treatment responses at different ages remains one of the most significant of these challenges.Both authors contributed to the conception and preparation of this manuscript. LC contributed to the first draft and the content relating to asthma management in adults. JP provided his summary and expertise on treatment of asthma in children. Both authors contributed to manuscript revisions, read and approved the submitted version.LC has received honorarium for lectures and advisory board meetings from GlaxoSmithKlein, AstraZeneca, Boehringer Ingelheim, Menarini, and Novartis.The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Effective adaptation action to climate change requires a balance between reducing vulnerabilities and managing risks. However, in most adaptation actions, risks such as greenhouse gas emissions, and those that impose negative externalities on global communities and ecosystems, are often overlooked. This article contextualises adaptation of maize stover (MS) as a dairy cattle feed among resource-poor farmers in western Kenya. In so doing, it attempts to establish the nexus between resource constraint and maladaptation to climate change. Simulation of methane emissions was carried out from secondary data and a survey of dairy cattle feeding strategies by resource-poor farmers. The level of greenhouse gas emissions in dairy feeding strategies is used as a measure and indicator of sustainability. Using disaster risk reduction principles, policymakers and community of practice in climate change action are encouraged to design and implement policies and strategies that take cognisance of poverty–maladaptation–environmental degradation nexus. Many parts of the world have been experiencing growing urbanisation and change in dietary preferences that favour dairy production. However, a current and projected increase in levels of milk production would not be possible without expanding production and yield of crop agriculture, hence an increase in demand for land. The lack of additional available land except in parts of tropical Latin America prohibits horizontal expansion of existing modes of dairy cattle production. This necessitates search for alternative dairy feed resources , produce 15% – 25% of total methane gas emissions, 74% of which is caused by cattle Tamminga . Enteric4). However, carbon (IV) oxide (CO2) produced by ruminants, notably cattle, is of less concern because it originates entirely from newly generated biomass and does not contribute to its net rise in the atmosphere. This leaves methane as the gas of concern (Tamminga 2 (Hope 2 on gram per gram basis over a period of 100 years (Tamminga Ruminants produce carbon (IV) oxide and methane .Unplanned or autonomous adaptation to climate change could be a driver to degradation of land resources, ecosystems and biodiversity, with far-reaching negative impacts on food security, incomes of small-scale farmers and poverty reduction initiatives. According to Jung et al. (2012), development paths and the choices that define adaptation may affect the severity of climate impacts, not only through changes in exposure and sensitivity but also through changes in the capacities of systems to adapt. This includes local-scale disaster risk reduction (DRR) and resource management and broader social dimensions Haddad . HoweverAccording to C-CIARN Agriculture , adaptatTo maintain or improve their livelihoods, farmers have to adapt to changing policy contexts and environment in which they operate . The higher marginal increment in CH4 emissions, on average, exacerbates radiative forcing than what would be under higher dairy productivity. Addressing the multiple risks faced by the smallholder dairy farmers can positively influence integration and intensification of dairy feeding strategies that use MS to reduce methane emission risks by 30%  at household and national levels, as well as resource base can be used to simulate outcomes of adaptive action. In dairy cattle production, energy and protein supplementation are a production risk management strategy. The analogy is applied in this article to assess the effect of MS supplementation on emission of methane.From the above analysis, the authors suggest an analytical framework  for poliThe introductory and the analytical frameworks provide evidence on poverty–maladaptation–environmental degradation nexus. Therefore, this article focuses on specific issues that are critical to sustainability and climate change mitigation and adaptation and argues that integrating the risk component provides the basis for comprehensive policy analysis and response, risk assessment and mainstreaming of sustainability concerns into agricultural sector adaptation to climate change. Using the level of methane emission from different dairy feeding strategies, issues that impinge on poverty–maladaptation–environmental degradation nexus are examined.Changes in climate and their effects have serious threats on the stability and productivity of the agricultural sector FAO . A studyThe changing climatic conditions, particularly rainfall and temperature patterns, portend adverse impacts on Kenya’s socio-economic sectors, with current projections indicating that such impacts will worsen in the future if significant reductions in the anthropogenic GHGs emissions that are responsible for climate change are not made GOK . As agriAbout 40% of dairy cattle in Kenya are found in semi-intensive farming systems. This feature, coupled with information that such production systems have the highest maize densities, indicates a high potential for benefits from maize–livestock integration . The area is characterised by commercial sugarcane farming as well as maize production at subsistence and commercial levels as major economic activities KNBS . LivestoThe western Kenya maize–sugar belt is under increased population pressure . Diminishing land sizes and seasonality in production of the feeds makes it difficult to bridge protein and energy gaps in dairy cattle feeding  while maintaining or enhancing its capacities and assets and at the same time not undermining the natural resource base at local and global levels in the short and long-term  and protein (6.5 ± 1.5%) supplementation by households is reflected in low milk production levels (3 ± 1.5 L) against potential of 20 L/day for dairy breeds of medium milk production potential in the study area. As shown in A farmer may perceive a technology as high risk if it requires investing a higher proportion of his or her limited resources  or foregoing a practice that is culturally valued  in the current system (Maredia & Minde In the above analysis, accumulated capital allows for purchase and use of external inputs, such as dairy feed supplements. This can significantly impact poverty outcomes and environmental degradation, as external inputs such as energy and protein supplements in dairy production significantly influence methane emission risks that impact environmental sustainability. Higher productivity of the dairy herd from increased use of external inputs not only reduces poverty but also reduces methane emission per unit litre of milk produced.The authors have used methane emission levels in the adaptation of dairy feeding strategies as a measure of sustainable development. It is apparent that mitigating GHG emission risks is one of the pillars of sustainable adaptation to climate change in dairy production. In this study, price risks are intricately associated with maladaptation to climate change among resource-poor farmers. While anecdotal evidence points to pollution and/or environmental degradation caused by the use of external inputs in crop agriculture, considerations of GHG emission levels in the use of MS suggest otherwise. Increased levels of energy and protein supplementation mitigate GHG, with positive impacts on environmental and financial sustainability. The counterfactual seems to suggest that any policy on adaptation and poverty–environmental degradation nexus has to be resource specific. From the analysis, it is clear that climate change can be a driver of disaster risks when economic vulnerabilities that reduce access to inputs and resources that mitigate GHGs are prevalent. Tackling the underlying disaster risk drivers, such as cognitive failure, poverty and poor natural resource management, is thus critical to risk reduction.Using MS as a specific feed resource in price and production risk contexts, this study identified potential pathways on poverty–production risks–maladaptation to climate change–Environmental degradation nexus. Simulation of methane emissions from small-scale farmers’ dairy cattle feeding adaptation strategies suggests that low or non-existent supplementation in MS-based rations is associated with higher-than-average methane emissions. The findings of the study underscore the centrality of hazard vulnerability risk assessment and multisectorial planning in the design of sustainable adaptation frameworks. Accordingly, adaptation frameworks should pay close attention to socio-economic issues, social organisations and institutions as the basis for risk-informed policies in general and for the assessment, prioritisation, monitoring and evaluation of climate change adaptation actions for the agricultural sector in particular.


We articulate the role of biomaterials in these emerging nucleic acid technologies in order to enhance the clinical impact of nucleic acids in the near future.Biomaterials play a critical role in technologies intended to deliver therapeutic agents in clinical settings. Recent explosion of our understanding of how cells utilize nucleic acids has garnered excitement to develop a range of older  and emerging  nucleic acid agents for therapy of a wide range of diseases. This review will summarize biomaterials-centered advances to undertake effective utilization of nucleic acids for therapeutic purposes. We first review various types of nucleic acids and their unique abilities to deliver a range of clinical outcomes. Using recent advances in T-cell based therapy as a case in point, we summarize various possibilities for utilizing biomaterials to make an impact in this exciting therapeutic intervention technology, with the belief that this modality will serve as a therapeutic paradigm for other types of cellular therapies in the near future. We subsequently focus on contributions of biomaterials in emerging nucleic acid technologies, specifically focusing on the design of intelligent nanoparticles, deployment of mRNA as an alternative to plasmid DNA, long-acting (integrating) expression systems, and  Nucleic acids provide seemingly infinite opportunities to undertake molecular therapy and remedy the abnormal physiology, and furthermore “personalize” the intervention with the knowledge of patient-specific complementary information. Ever since the recombinant technology has been advanced to produce natural and engineered proteins en mass , ex vivo cell expansion, mRNA delivery, and long-term transgene expression. This review will primarily focus on (i) therapeutic (rather than diagnostic) modalities, and (ii) non-viral, biomaterials-centered methods to undertake effective delivery of nucleic acids. The authors acknowledge that exciting developments are taking place in viral design and engineering to undertake clinical therapy, but we refer the reader to other sources on recent developments on this front  transposon system, wherein one pDNA carries the SB transposase gene while the other pDNA carries the gene of interest flanked by the transposase recognizable terminal inverted repeats (TIRs). The capability of the transposon system to permanently insert transgene constructs in the host genome and relatively superior biosafety profile, makes the SB approach advantageous over non-integrating non-viral vectors and viruses, respectively  or supplement an additional capability such as morphogen-induced tissue regeneration. The use of viruses has been favored to ensure effective (increased uptake) and long-lasting  transgene expression, but using plasmid DNA (pDNA) and other naked nucleic acids eliminates several undesirable viral effects, as long as the delivery is effective. It has been possible to design tissue-specific, inducible, minimally-recognizable and “mini” pDNAs to overcome various limitations of the initial pDNA configurations. In addition to circular pDNA, it is possible to rely on other configurations of functional genes; the expression cassettes may come in various molecular weights, conformation and topologies  that “neutralize” and block translation of target mRNAs were initially pursued that rely on in situ production of silencer molecules  through typical pDNA-based expression vectors. While the latter relies on nuclear targeting for efficient expression, siRNAs can be delivered to the cytoplasmic space to engage the RNA-induced silencing complex (RISC) directly with minimal processing by host cells. To achieve sustained silencing of gene expression, siRNA needs to be continually supplied exogenously, or stable integration and expression is required in the case of shRNAs. The exciting possibilities with RNAi was recently (2018) confirmed with the FDA approval of the first siRNA based drug (Patisiran by Alnylam) to treat the nerve damage caused by the rare disease hereditary transthyretin-mediated amyloidosis (hATTR) in adults. To further regulate gene expression, endogenous miRs, the non-coding single stranded RNAs with 19 to 25 nucleotides and mis-matched base pairing, can be introduced into host cells either to augment or “mimic” a particular miR. In cases where the elevated miRs themselves are the cause of underlying pathophysiology and need to be down-regulated, single stranded RNA molecules with sequence complementary to a target miR, an anti-miR, could be deployed.The endogenous RNA interference (RNAi) mechanism has been adopted for therapy by silencing genes based on blockage and/or degradation of corresponding mRNAs. RNAi can be implemented with synthetic short interfering RNAs , as well as in vivo. To enhance stability and ensure proper folding into its active structure, ribozymes are expressed as part of a larger transcript, called carrier RNA, the sequence of which is carefully chosen so that the resulting transcript not only adopts a secondary structure that does not impede ribozyme activity but is also stable  have been recently identified whose sole function seem to sequester and alleviate the effects of intracellular molecules responsible for undesirable changes. It may be possible to alter the activity of specific DNA, RNA, and protein targets by deploying lncRNAs ‘sponges.' Sponging may be additionally undertaken by so called circular RNAs (circRNAs) distinct from linear lncRNAs and miRs, featuring higher cellular stability due to the absence of free ends and resistance to exonucleolytic degradation. CircRNAs may harbor one or more binding sites for a single miR or possess binding sites for multiple miRs, thereby regulating entire miR families   structures for binding to their target proteins through structural recognition and inhibit their interactions with other molecules in a manner similar to protein antagonists and antibodies, thereby serving as decoys. Their ability to recognize and bind highly structured nucleic acid targets lends them a unique functionality that may be more advantageous over previously mentioned agents . While extracellular molecules can be targeted by exogenous aptamers with relative ease, in situ translated mRNA  /Cas9 nuclease is providing exciting possibilities but also raising the bar for biomaterial-mediated delivery. The CRISPR/Cas9 system requires a single guide RNA (gRNA) and the Cas9 nuclease to undertake gene editing. For practical implementation, alongside the gRNA, the Cas9 nuclease may be delivered directly as a protein, as a pDNA cassette for protein expression in host cell, or as a “translatable” mRNA  in the thymus to recognize foreign antigens from infectious pathogens as well as tumor antigens  agonist, serving as a vaccine in pancreatic and melanoma mice models  NPs, both successfully generating CD19-CAR T cells in vivo  or invading (in vivo) cells  in nucleic acid bearing NPs will be the way forward to realize more effective therapeutic outcomes from nucleic acids. Despite emergence of a wide range of synthetic, “intelligent” materials for NP fabrication in the last decade, there is still a need to create new functional NPs for hard-to-transfect cell types. Using commercial and in-house developed non-viral reagents, the authors frequently encounter cell types  that are exceptionally difficult to transfect. Patient-derived cells in particular have shown variable results in our hands for siRNA-mediated silencing of therapeutic targets, with significant fraction of cells either not responding or responding weakly to nucleic acid treatments  assembled on NP cores; they were shown to effectively penetrate the blood-brain-barrier as well as the blood-tumor-barrier and implement the RNAi silencing pathway  to modulate the release of mRNA are an effective approach to vaccination , leading to comparatively better results in certain animal models. Lower doses of nucleic acids/synthetic carriers may minimize adverse inflammatory/immune reactions that may impede new tissue induction. The delivery system used in mRNA delivery were not particularly tailored in these early studies , so that improved carriers are bound to further improve regeneration with reduced doses. Collectively, these studies indicate that a robust translation of mRNA for ~10 days in vitro appears to be sufficient for effective tissue induction in small animal models. Investigations in larger animals, however, will be required to truly assess clinical potential. Considering that μg quantities of BMP proteins are needed for effective regeneration in small animals and that clinical therapy in the past relied on 10–20 mg of the protein in situ, it will be important to determine the functional mRNA doses in larger preclinical models to better assess its potential for clinical translation.Bone induction by mRNA translation is another indication where transient transgene expression might be sufficient for clinical success. Morphogens such as Bone Morphogenetic Proteins (BMPs) are known to “kick-start” the osteogenesis process beyond a critical concentration and their continued presence might not be required to sustain tissue induction and repair. The precise design of mRNA with particular chemical and end-group modifications are critical for effective translation, but several successful configurations have emerged for relatively long term protein production indicating some flexibility in the mRNA design. A longer sustained expression was noted when a BMP-2 morphogen was delivered with mRNA in scaffolds, presumably reflecting favorable pharmacokinetics and cell exposure   2 fragment) in a murine model , but this was sufficient for target cell killing and matched the performance of lentiviral-modified T-cells. The low levels of transfection will translate into benefit in terms of lower non-specific binding (and modification) of non-target cells. The extent of in vivo modification was similar with ~5% of circulating T-cells displaying transgene expression after 6 days, but the cells expanded with increasing population of cells displaying CAR expression (~20% after day 12), that was dependent on transposase delivery. In the absence of transposase delivery, no effective anti-tumor response was seen, clearly indicating the beneficial effect of vector integration. A similar delivery system was used for transiently transfecting T-cells with mRNA, whose biocompatibility was compared to electroporation modified cells  that favors the expansion of desirable population of T-cells, that may provide a superior alternative to transient delivery systems towards the ultimate goal of integrated (long-acting) vectors  was recently identified as a mediator of TCR activation . Nucleic acids themselves derived from DNA and RNA molecules have the potential to replace synthetic biomaterials and act as carriers for nucleic acid agents  intended to develop nucleic acid based therapies and declares conflict of interest. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Intergroup biases can manifest themselves between a wide variety of different groups such as people from different races, nations, ethnicities, political or religious beliefs, opposing sport teams or even arbitrary groups. In this review we provide a neuroscientific overview of functional Magnetic Resonance Imaging (fMRI) studies that have revealed how group dynamics impact on various cognitive and emotional systems at different levels of information processing. We first describe how people can perceive the faces, words and actions of ingroup and outgroup members in a biased way. Second, we focus on how activity in brain areas involved in empathizing with the pain of others, such as the dorsal anterior cingulate cortex (dACC) and anterior insula (AI), are influenced by group membership. Third, we describe how group membership influences activity in brain areas involved in mentalizing such as the medial prefrontal cortex (mPFC) and temporoparietal junction (TPJ). Fourth, we discuss the involvement of the lateral orbitofrontal cortex (lOFC) in increased moral sensitivity for outgroup threats. Finally, we discuss how brain areas involved in the reward system such as the striatum and medial orbitofrontal cortex (mOFC), are more active when experiencing schadenfreude for outgroup harm and when rewarding ingroup (versus outgroup) members. The value of these neuroscientific insights to better understand ingroup bias are discussed, as well as limitations and future research directions. There is increasing neuroscientific evidence that people process information from ingroup and outgroup members in a different way . Using fMRI, Figure 2).People do not only process faces in a biased way but also process the words of ingroup and outgroup members through a selective lens. Participants who identified as strong supporters of a political party rated identical statements during an fMRI experiment as more inspirational if they believed they came from ingroup (vs. outgroup) leaders . NeuroimSimilar biased information processing was also found in an fMRI study by In addition to faces and words, neuroscience studies have shown that people process the actions of ingroup and outgroup members differently e.g., . A famouThe researchers separately modeled brain activations during the observation of the actions and when participants made their decision. No differences in brain activation were found when participants decided that their own (vs. other) team was faster, suggesting they were not deliberately favoring their own team. When looking at brain activation during action observation, the authors split the group into those who said that their team was, on average, faster than the other group. Neuroimaging results revealed that only participants who said that their team was faster showed more activation in the inferior parietal lobule , cognitive empathy , and emotional regulation , with separate brain circuits associated with each type of empathy . Here weAnother fMRI study that used similar stimuli examined whether a general social group category, other than race, could similarly modulate neural empathic responses and perhaps account for the apparent racial bias reported in previous studies . Using aAnother fMRI study examined empathetic responses in soccer fans . ParticiReduced activation in the AI between watching ingroup and outgroup members in pain was also reported in an fMRI study in which White and Black participants watched video clips of white and black hands receive either painful stimulation by a syringe or non-painful stimulation by a Q-tip . ParticiThe fMRI studies reviewed in this section suggest that people typically activate brain regions associated with watching others in pain, such as the dACC and AI, less when observing outgroup (vs. ingroup) members in pain. Individual ingroup bias differences in neural responses in these regions is also associated with reduced helping behavior , and incMentalizing (aka Theory of Mind) refers to our ability to explain and predict other people’s behavior by attributing to them independent mental states, such as beliefs, intentions and desires . MentaliFor example, In another fMRI experiment, African-American and Caucasian-American participants watched pictures of African-American or Caucasian-American people in painful  and non-painful  situations . AfricanAnother fMRI study by The results in this section suggest that brain areas associated with mentalizing are typically less activated when thinking about the mindset of outgroup members . HoweverPeople are usually highly sensitive to menaces and attacks from outgroup members against the ingroup because they could pose an existential threat. Attacks against ingroup members increase thoughts about one’s own mortality and lead to increased prejudice toward outgroup members . IncreasSuch increased activation in lOFC in response to outgroup threats was also found in an fMRI study by Schadenfreude is a feeling of pleasure derived from another person’s misfortune. Under some circumstances , harming outgroup members, or seeing them in pain or experiencing misfortune can lead to schadenfreude . For exaFor example, Intergroup bias in the reward system is not only observed when watching others in pain but also when rewarding others. In an fMRI study , universIn another fMRI experiment , ChineseFirst, we discussed how fMRI studies have shown that our brain responds differently to faces, words and actions of ingroup and outgroup members. Depending on the context, this selective processing of ingroup and outgroup faces might be harmless or lead to subtle forms of ingroup bias. However, under some circumstances this biased processing can lead to life-or-death situations. For example, if a police officer has to make a quick decision to shoot or not shoot a target based on whether he or she believes the person is holding a gun, then it is a major problem if that decision is influenced by the target’s skin color. Behavioral results have shown that police officers in America more likely choose the “shoot” versus “not shoot” response when the target is Black compared to Latino, White or Asian target . The fMRIn relation to statements from political leaders, behavioral studies on motivated processing of political information have shown that biased processing of information can lead to a strong polarization in political attitudes . The twoSecond, we discussed how reduced responses in the dACC and AI when seeing outgroup members in pain were associated with increased ingroup bias  and reduThird, we discussed how reduced mentalizing about the mindset of outgroup members was associated with reduced activity in the mPFC and the TPJ e.g., . HoweverFourth, we reviewed that there is increased moral sensitivity for outgroup attacks on ingroup members (associated with increased lOFC activation). This suggests that there is something specific about outgroup threats toward ingroup members that can lead to strong antisocial behavior toward this outgroup. Indeed, behavioral research has shown that Islamic terrorist threats and perceived support for terrorism by Muslims are important predictors of outgroup discrimination and support for anti-immigration policies in European countries, over and above standard predictors such as prejudice and political conservatism . Future Finally, we reviewed fMRI studies showing increased activity in the striatum and mOFC when observing outgroup harm  or when rewarding ingroup (vs. outgroup) members. The former usually only happens when there is a strong competition between the two groups or when the outgroup is strongly disliked. However, preferring to reward ingroup vs. outgroup members seems to happen already in minimal groups . These oHow do all of these findings fit together? The reviewed studies show that there is not a single brain area or system responsible for ingroup biases. Depending on the bias  and the modalities  implicated, different neural networks might be involved. We predict that combining multiple types of biases will lead to stronger antisocial behavior against the outgroup. For example, a perceptual bias in relation to action observation  by an ingroup member might result in seeing the action in a more favorable light than the same action performed by an outgroup member. This perceptual bias alone might not lead to violence between the two teams. However, if this perceptual ingroup bias is combined with biases in affective empathy and mentalizing, together with perceptions of threat to ingroup safety or schadenfreude for the suffering of an outgroup member, it is likely that all these biases together lead to violence between the two teams.Why is it important to better understand the neural mechanisms of ingroup bias? First, new models extending present neuroimaging findings are important from a theoretical point of view. They provide new knowledge , allow testing new predictions , and allow testing competing novel hypotheses that might sometimes not be possible to answer with behavioral methods alone . Second, future studies could use these insights to target brain areas involved in intergroup bias with non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation TMS;  or real-There are also several important limitations to the neuroimaging study of ingroup bias at present. One question to ask is whether cognitive processes can be inferred from neuroimaging data at all  and the specific cognitive process  implicated, different molecular, neuroendocrine and neural processes may be involved in creating intergroup bias .To conclude, the goal of this review was to bring together a wide variety of findings from fMRI studies to help explain and guide future research into the neuroscience of intergroup biases. Given the enormous consequences of positive and negative intergroup contact on a human and economic level, it is of crucial importance to acquire a better understanding of the behavioral and neural mechanisms that drive intergroup bias and violence.PM wrote the initial draft of the paper. WL provided substantial contributions to the final version of the paper.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer CP and handling Editor declared their shared affiliation at the time of the review.


Recent advances in neuroscience and devices are ushering in a new generation of medical treatments. Engineered biodevices are demonstrating the potential to create long-term changes in neural circuits, termed neuroplasticity. Thus, the approach of engineering neuroplasticity is rapidly expanding, building on recent demonstrations of improved quality of life for people with movement disorders, epilepsy, and spinal cord injury. In addition, discovering the fundamental mechanisms of engineered neuroplasticity by leveraging anatomically well-documented systems like the spinal cord is likely to provide powerful insights into solutions for other neurotraumas, such as stroke and traumatic brain injury, as well as neurodegenerative disorders, such as Alzheimer’s, Parkinson disease, and multiple sclerosis. Now is the time for advancing both the experimental neuroscience, device development, and pioneering human trials to reap the benefits of engineered neuroplasticity as a therapeutic approach for improving quality of life after spinal cord injury. Traditional neuromodulation systems that stimulate the brain and spinal cord are already improving the lives of hundreds of thousands of people. Current systems typically apply stimulation in an open loop, continuous way and provide relief of symptoms, such as essential tremor or chronic pain only during operation.The next generation of neural devices operate in a close-loop framework. These devices sense symptom onset and stimulate only when needed. Examples include the NeuroPace device for epilepsy treatment , and expAn emerging approach aims to use closed-loop or activity-dependent stimulation to produce long-term changes in neural circuits after injury or disease. Producing such engineered neuroplasticity would mean that operation of the device is no longer necessary after effectively rewiring or otherwise repairing the disordered neural circuits in the brain or spinal cord. Exciting examples of this approach are rapidly emerging, and the potential for combining engineered plasticity with biological and pharmacological therapies is profound.In the late 1940s, Donald Hebb described the principle by which neurons form and strengthen connections within neural circuits [Users of implanted visual prosthesis provide indirect evidence that neural devices can effect long-term changes in brain connectivity. James Weiland and colleagues coined the term “bioengineered neuroplasticity” to describe their observation of brain changes following prolonged use of the Argus II retinal prosthesis. Whereas the visual cortex of blind participants typically responds to both visual and tactile stimulation , use of The first direct demonstration of engineered neuroplasticity was provided by Andy Jackson and Eberhard Fetz, who discovered that a closed-loop device could durably rewire circuits in the brain . By recoThe timing of closed-loop stimulation is critical to inducing long-term changes in neural circuits. Jackson and Fetz observed the greatest effect using a delay of about 20 ms between the recorded neural activity and subsequent stimulation, with less change in neural circuits using shorter and longer delays. This phenomenon of engineered neuroplasticity has since been demonstrated to improve recovery by bridging a traumatic brain injury .Yukio Nishimura also working with Eberhard Fetz expanded this paradigm to change the strength of connectivity between the brain and the spinal cord . IdentifThus, engineered plasticity can both strengthen and weaken natural synaptic connections, providing a robust and flexible platform for treating spinal cord injury (SCI). For example, following SCI the neural device may be set to enhance connections within the motor or somatosensory pathways. Conversely, the device may be used to reduce connectivity and excitability in aberrantly overactive pathways, such as the stretch reflex that can lead to spasticity and hyperreflexia following SCI . John WoNeural stimulation devices can also be paired with natural activity to produce long-term recovery of function after injury . StimulaThe most likely mechanism of action for both epidural and transcutaneous spinal stimulation involves activation of the dorsal root afferent fibers , and resIn addition to restoring movement during periods of spinal cord stimulation, many of these participants also had long-term gains in autonomic functions, such as bladder, bowel, thermoregulation, and cardiovascular function that are critical health problems following spinal cord injury , 27. TheWhile the majority of studies utilize electrodes surgically implanted on the spinal cord surface, termed epidural stimulation, even stimulation applied to the skin surface over the spinal cord may lead to engineered neuroplasticity. Spasticity of the lower extremities is reduced following the application of transcutaneous electrical  or magneBased on the improvements observed to date from non-invasive stimulation, it seems sensible to suggest that transcutaneous stimulation be tested prior to undergoing surgery to implant an epidural stimulation electrode. Transcutaneous stimulation may serve as a screening tool to see who might respond to epidural stimulation. This would be less invasive than the temporary, percutaneous leads that are placed prior to internalizing the pulse generator for treatment of chronic pain, which have been used to test the potential benefit of epidural stimulation in one case . RegardlIn addition to open-loop stimulation of the spinal cord, neural technology now permits closed-loop systems capable of bridging the spinal cord injury. Neural activity can be recorded from electrodes in or near the brain to indicate the intention to move, and stimulation delivered to the paralyzed muscles to restore functional grasp in both animal models , 33 and The aforementioned strategy of bridging the injury by recording in the brain and stimulating distal to the injury could be viewed largely as a prosthetic solution. Recent evidence, however, suggests that operation of such a closed-loop device can lead to long-term changes in natural connectivity bypassing the lesion. Indeed, after several years of using a brain-controlled muscle stimulator to promote hand function , the parThe functional improvements resulting from neural devices reported to date are already life-changing for the small number of people involved in these studies. When these strategies are successfully translated to clinical practice, there will be a dramatic shift in quality of life for people with neurological disorders. For example, restoration of hand and arm function after spinal cord injury or stroke can restore independence in feeding, dressing, and grooming, thereby substantially reducing caregiver burden and costs. Restoration of bladder and bowel functions reduces life-threatening bladder and kidney infections, saves many hours each day currently devoted to bowel programs, and restores confidence and dignity, permitting engagement in social situations and travel.Given that most recent breakthroughs in engineered plasticity have utilized noninvasive stimulation or implanted epidural stimulators already approved for other indications, the timeline for translation to clinical care can be unusually short. The US FDA has been very cooperative in pre-submission meetings, proactive in gathering information from the researcher community, and even approving the Expedited Access Pathway for some of these emerging technologies. For example, multisite clinical trials of transcutaneous spinal stimulation are already beginning, and assuming that safety data continue to be positive, this new treatment could be available to patients in as little as 2–3 years.Epidural stimulators are already approved for the treatment of chronic pain. Multiple centers are currently studying the benefits of epidural stimulation for restoring movement after spinal cord injury under FDA investigational device exemption (IDE), and all are obtaining highly promising results . Therefore, efficacy need only be demonstrated for new applications of movement restoration, and perhaps also engineered neuroplasticity of autonomic function, over the next 3–5 years.Even the development of closed-loop implantable brain stimulators are already well underway. NeuroPace recently received approval for an implant to treat epilepsy, and Medtronic is testing several low channel-count devices for treatment of essential tremor and Parkinson disease. Both startup  and established companies  are ramping up to produce more complex closed-loop devices, which are expected to emerge in the next 5–10 years to enable specific and targeted engineered neuroplasticity.It is critical to remember that even approaches targeting the peripheral nervous system (PNS) will need to consider plasticity occurring in the central nervous system (CNS) and associated ganglia. Treatments to excite or block the PNS are likely to evoke long-term changes within circuits of the CNS as homeostatic mechanisms counter the applied neuromodulation. Thus, a keen awareness of engineered neuroplasticity will likely be needed in order to produce effective neuromodulation in both peripheral and central targets to improve function in a wide range of diseases.While stimulation devices can be rapidly translated to clinical practice, perhaps the greatest benefit of engineered neuroplasticity will be realized in combination with other treatments over a slightly longer time horizon. There exists a unique potential for devices to collaborate with biological and pharmacological therapies to produce targeted and robust regeneration of neural circuits.For example, neural stem cell grafts hold great promise for restoring function to degenerating or damaged neural tissue. Approaches involve neuron cell replacement, remyelination, and environment modulation. The potential for cell replacement is demonstrated by human induced pluripotent stem cells (hiPSCs), grafted into the injured spinal cord, that extend axons long distances into the host tissue . WithoutDemyelination occurs after spinal cord injury , and durIn addition to electrical stimulation, cell-based approaches aim to promote remyelination and restore conduction in damaged axons of the spinal cord. There are currently human trials ongoing for both the approach of using oligodendrocyte precursor cells (OPCs)  and SchwA final intriguing benefit of stem-cell transplantation may be to beneficially modify the host environment to induce plasticity and regeneration. This may partly explain the benefits of olfactory ensheathing cells (OECs) that secret proteins, such as metalloproteinases known to improve host axon regeneration . For exaSimilarly, pharmacological interventions may generally enhance neuroplasticity, while engineered devices can collaborate to shape this plasticity into specific and functional circuits . An examIt should be noted that combinatorial therapies are not always beneficial, and can even be counterproductive if administered simultaneously. For example, treatment with anti-Nogo anti-body and motor retraining must be staggered in time in order to observe benefits following stroke or spinal cord injury , 61. DesAn additional target for axon and neurite outgrowth is the Rho/ROCK pathway, which may benefit the damaged brain or spinal cord . This pacombined with locomotor retraining resulted in improved function [closely followed by treadmill training led to greater improvements than either treatment alone [Regardless of the cell therapy or plasticity-enhancing pharmacology selected, appropriate neural activity is likely needed to create functional benefit from these studies. As examples, cord blood stem cells function . Treatment alone . And preWhile engineered neuroplasticity has been demonstrated to effect long-term changes throughout the central nervous system (CNS), the spinal cord after injury offers a tractable anatomical model of CNS repair. The spinal cord contains all of the cell types and neural circuits found in the brain, but arranged in a physical organization where lesions can reliably disconnects discrete spinal circuits. While studies of neuroplasticity in the brain have been largely inconclusive, the spinal cord provides an ideal testbed for understanding and optimizing plasticity-inducing treatments within the CNS. There is an opportunity to leverage advances in the fundamental understanding of engineered neuroplasticity combined with biological and pharmacological therapies to advance treatments for spinal cord injury. While directly advancing treatments for spinal cord injury, discoveries are also expected to have an impact on developing new treatment options for other neurological disorders, such as stroke, traumatic brain injury, Alzheimer’s, Parkinson disease, and multiple sclerosis. Therefore, the approach of engineered neuroplasticity may hold the key to unlocking advances in clinical treatments throughout the brain and spinal cord.