Levothyroxine replacement therapy may decrease the risk of adverse pregnancy outcomes among women with subclinical hypothyroidism (SCH). The aim of this study is to conduct a systematic review and meta-analysis to examine the risk of adverse pregnancy, perinatal, and early childhood outcomes among women with SCH treated with levothyroxine.A systematic literature search was conducted using Ovid-Medline, Ovid-EMBASE, Pubmed (non-Medline), Ebsco-CINAHL Plus with full text and Cochrane Library databases. Randomized controlled studies (RCTs) and observational studies examining the association between treatment of SCH during pregnancy and our outcomes of interest were included. Studies that compared levothyroxine treatment versus no treatment were eligible for inclusion. Data from included studies were extracted and quality assessment was performed by two independent reviewers.Seven RCTs and six observational studies met our inclusion criteria. A total of 7342 individuals were included in these studies. RCTs demonstrated several sources of bias, with lack of blinding of the participants or research personnel; only one study was fully blinded. In the observational studies, there was moderate to serious risk of bias due to lack of adjustment for certain confounding variables, participant selection, and selective reporting of results. Pooled analyses showed decreased risk of pregnancy loss  and neonatal death  associated with levothyroxine treatment during pregnancy among women with SCH. There were no associations between levothyroxine treatment and outcomes during labour and delivery, or cognitive status in children at 3 or 5 years of age.Treatment of SCH with levothyroxine during pregnancy is associated with decreased risks of pregnancy loss and neonatal death. Given the paucity of available data and heterogeneity of included studies, additional studies are needed to address the benefits of levothyroxine use among pregnant women with SCH.The online version contains supplementary material available at 10.1186/s12902-021-00699-5. Subclinical hypothyroidism (SCH) is a common biochemical entity identified in women during pregnancy. SCH is diagnosed when the thyroid stimulating hormone (TSH) is elevated with a normal free thyroxine (FT4) level. Although most women with SCH are asymptomatic, previous studies have shown that SCH may be associated with adverse outcomes during pregnancy –3.The thyroid hormone, FT4, is necessary for fetal growth and development. Insufficient thyroid hormone has been shown to impair fetal growth  and it mSeveral studies have examined the association of SCH and adverse outcomes during pregnancy and long-term outcomes in mothers and children including pregnancy loss, pre-term delivery, gestational diabetes, gestational hypertension, eclampsia, placental abruption, low birth weight, and childhood cognitive outcomes –14. SevePrevious meta-analyses have been performed on this topic. However, these meta-analyses have focused on comparing women with SCH with euthyroid women during pregnancy , 12 or oDue to the lack of good quality evidence for treatment of SCH during pregnancy, it is unclear whether levothyroxine treatment should be given to women with isolated SCH during pregnancy . To examOur systematic review was conducted following a pre-specified protocol and is reported based on the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement . The stuWe systematically searched Ovid MEDLINE (Appendix 1), Ovid EMBASE (Appendix 2), Ebsco-CINAHL Plus with Full Text (Appendix 3), Pubmed (for articles not indexed in Medline) (Appendix 4), and Cochrane Library from inception to July 18, 2018 to identify studies that examined the association between treatment of SCH during pregnancy and adverse pregnancy outcomes. A medical librarian (FF) designed and conducted the searches (see Appendix for full search strategies). The Ovid-Medline search was peer reviewed by a second librarian using the Peer Review of Electronic Search Strategies (PRESS) guideline [We included interventional and observational studies that reported the risk of adverse pregnancy outcomes with and without levothyroxine treatment among women with SCH. Inclusion was restricted to studies in which SCH was defined by a TSH level between 2.5 and 10 mIU/L at any time during pregnancy and included women with SCH identified pre-pregnancy. We based our definition of SCH on the 2011 ATA guidelines , which iAfter removing duplicates, two independent reviewers screened the titles and abstracts of identified publications, with any publication deemed potentially relevant by either reviewer carried forward to full-text review. Discrepancies during full-text review between reviewers were resolved by consensus or a third reviewer (IK or KBF).Quality assessment and data extraction were performed for all included studies by two independent reviewers (MB and OY), with disagreements resolved by consensus or by a third reviewer (IK or KBF). The Cochrane Risk of Bias tool was used for RCTs  and the 2 statistics. We conducted the analyses using the meta package [R [Given the paucity of RCTs that assessed the risk of adverse events during pregnancy with levothyroxine treatment among women with subclinical hypothyroidism, we performed our primary analysis, pooling findings from RCTs and observational studies . By incl package  in R [30We performed six sensitivity analyses. First, to address the influence of levothyroxine treatment for women with SCH caused by an autoimmune condition, we repeated our analyses including only studies that addressed the risk of adverse pregnancy outcomes among women with TPOAb positivity who were treated with levothyroxine versus untreated women. Second, the meta-analysis was repeated after excluding studies that assessed women with a history of infertility or recurrent miscarriages, as women with these conditions may have a higher risk of adverse pregnancy outcomes. Third, given that one of the prospective clinical trials did not utilize randomization compared to the other prospective clinical studies , we repeSeven RCTs and six cohort studies were included from a total of 3953 articles identified by our search Fig. . ThyroidOne RCT fulfilled all quality criteria  and was The included cohort studies had a moderate to serious risk of bias Table S. Three dCongenital malformation, fetal distress, fetal macrosomia, oligohydramnios, placenta previa were reported in single studies and thus meta-analyses were not possible Table . Meta-anLevothyroxine treatment among women with SCH was not associated with placenta abruption, postpartum hemorrhage, premature rupture of membranes, preterm delivery, or preterm labour Table -S7. FourNeonatal outcomes assessed included neonatal death, 5-min Apgar score, and low birthweight Table , Table 3Only two RCTs assessed the association between levothyroxine treatment and behavioral and cognitive outcomes of children of women with SCH Table . These RTwo studies addressed whether levothyroxine treatment was associated with pregnancy outcomes among women with SCH caused by autoimmune disease (diagnosed by elevated TPOAb levels) . NazarpoSensitivity analyses that excluded studies of women with a history of infertility or who conceived with fertility treatments , 39 and In this systematic review and meta-analysis, we assessed the available evidence regarding the use of levothyroxine in treating SCH during pregnancy. We found that the use of levothyroxine among women with SCH was associated with a decreased risk of pregnancy loss and neonatal death relative to non-use. Although available data are limited, there is also evidence that levothyroxine treatment is associated with improved fetal outcomes, including reductions in fetal distress and macrosomia. We did not observe associations between treatment with levothyroxine and other adverse outcomes during pregnancy, labor and delivery and postpartum. Finally, there was no evidence of associations between levothyroxine use during pregnancy and cognitive outcomes in children. However, there was heterogeneity with respect to study populations and timing of initiation of levothyroxine between the included studies. Given the limited quality of the available data and its heterogeneity, additional high-quality studies are needed.There is well-established evidence for the need to treat women with overt hypothyroidism during pregnancy as studies have shown that untreated hypothyroidism during pregnancy leads to increased risk of pregnancy complications, including increased risks of preterm birth, low birth weight, and stillbirth , 44. ThrA recent systematic review and meta-analysis of studies comparing women with SCH and euthyroid women during pregnancy found that SCH was associated with an increased risk of multiple adverse maternal and fetal outcomes , includip = 0.004). None of the other studies in our meta-analysis addressed whether later initiation of levothyroxine had any impact on pregnancy outcomes.The majority of the studies performed to date initiated levothyroxine during the first trimester with only two studies addressing the effects of initiating levothyroxine at other times during pregnancy . Ju et aThe presence of TPOAb has been shown to increase the risk of pregnancy loss by approximately two-fold among women with SCH , 52. FurLevothyroxine treatment for SCH during pregnancy may decrease the risk of pregnancy loss among women with infertility , 31, 39,Our study has several potential limitations. First, statistical heterogeneity was present in many of our analyses. This heterogeneity is likely due to differences in study design, sample populations, geographical location, and temporal differences in the timing of levothyroxine initiation during pregnancy. There were also some differences in the definition of pregnancy loss across studies, a lack of information relating to TSH levels used to define SCH, and the timing of initiation of levothyroxine therapy. Given this heterogeneity, we used random-effects models to account for the within- and between-study variability. Second, our study defined SCH using the TSH cut-off limit of 2.5mIU/L recommended by the 2011 ATA guidelines . The recThis systematic review and meta-analysis found that, compared with non-use, levothyroxine treatment was associated with decreased risks of pregnancy loss and neonatal death among pregnant women with SCH. There was no association between levothyroxine treatment and the risk of other adverse outcomes including outcomes during labour and delivery, and cognitive status in children at 3 or 5 years of age. However, the quality of many of the included studies was modest and important heterogeneity was present. Consequently, further studies are required to address whether levothyroxine treatment among women with SCH improves pregnancy outcomes if given earlier during pregnancy, in women with autoimmune thyroid disease, and in women with a history of infertility or recurrent pregnancy loss.Additional file 1.


Extracellular vesicles (EVs), such as exosomes, are newly recognized fundamental, universally produced natural nanoparticles of life that are seemingly involved in all biologic processes and clinical diseases. Due to their universal involvements, understanding the nature and also the potential therapeutic uses of these nanovesicles requires innovative experimental approaches in virtually every field. Of the EV group, exosome nanovesicles and larger companion micro vesicles can mediate completely new biologic and clinical processes dependent on the intercellular transfer of proteins and most importantly selected RNAs, particularly miRNAs between donor and targeted cells to elicit epigenetic alterations inducing functional cellular changes. These recipient acceptor cells are nearby (paracrine transfers) or far away after distribution via the circulation (endocrine transfers). The major properties of such vesicles seem to have been conserved over eons, suggesting that they may have ancient evolutionary origins arising perhaps even before cells in the primordial soup from which life evolved. Their potential ancient evolutionary attributes may be responsible for the ability of some modern-day exosomes to withstand unusually harsh conditions, perhaps due to unique membrane lipid compositions. This is exemplified by ability of the maternal milk exosomes to survive passing the neonatal acid/enzyme rich stomach. It is postulated that this resistance also applies to their durable presence in phagolysosomes, thus suggesting a unique intracellular release of their contained miRNAs. A major discussed issue is the generally poorly realized superiority of these naturally evolved nanovesicles for therapies when compared to human-engineered artificial nanoparticles, e.g., for the treatment of diseases like cancers. Extracellular vesicles (EVs) denote a continuum of extracellular vesicles classified into four main subtypes according to size: largest apoptotic bodies (originating from dying cells), micro vesicles (MVs) or ectosomes , the most common exosomes sometimes called small EVs, and the smallest ectomeres. MVs or ectosomes pinch off singly from the cell surface, whereas exosomes pinch off from the intracellular terminal endosomal membranes to gather in growing dilated multivesicular bodies, eventually undergoing compound sequential exocytosis with subsequent extracellular release of the appropriately named exosomes. Though EVs are recommended by some as the overall term to use , this auWe propose that the family of nano-sized extracellular vesicle exosomes that are currently able to exchange genetic information between cells via transfers of various RNAs, as well as active proteins like enzymes, are related to and may be descended from ancient universal particles of life that preceded eukaryotic and even prokaryotic cells. Alternatively, the EVs could be related to such ancient primordial vesicles by having arisen again via convergent evolution. This universality of exosomes and their likely ancient origin are compelling reasons to prefer the use of these vesicles for therapies, as opposed to the misguided current creation of human-conceived artificial nanoparticles for ameliorating diseases. The exosome RNA content is, of course, even more ancient and likely dates back to near the origin of life known as the “RNA world” ,3. Concepts derived from contemporary experiments suggest that the origins and thus some unusual properties of subsets of these minute natural exosome EVs are related to proto-cells or pre-cell vesicles postulated to be involved in the origin of life ,4. TheseIndividual RNA nucleotides are thought to have formed in the natural primordial soup by spontaneous chemical processes made possible by the extreme harsh physical and chemical conditions that acted on available constituent atoms to form individual pre-RNA nucleotides via energy available from minor present toxic rare chemicals like cyanides ,10 and fOver time, the singly present intra-vesicular nucleotides spontaneously and non-enzymatically reacted with each other to form into polyribonucleotide chains  based onAs time advanced, multiple individual different advantageous RNA polynucleotides with differing RNase activities attained the ability to reproduce themselves ,20. ThisLakes in geothermal active areas provide a possible environment with fluctuating temperatures, such that they are cool in winter and, as within hydrothermal vents, otherwise emit streams of very hot water for transient high temperature exposure that then would promote RNA strand separation. These RNA- and RNase-carrying small vesicles with bilamellar membranes that have been called proto cells ,8,9 coulThus, during the processes of the origin of life, physical grouping in separated vesicles permitted a way for these replicator enzymes (polyribonucleotide polymers replicases) to nonrandomly interact. Thus, RNA replicases encapsulated in growing and dividing lipid membrane vesicles would tend to be trapped with sequences related to their own sequence and would thus preferentially copy those sequences. As such, an occasional aberrant or parasitic sequence would be separated from the active RNA polymerases during vesicle division and thus be unable to disable the system . Later in evolution when eukaryotic cells emerged, these RNA-containing ancient vesicles may have been retained as secreted EVs of the terminal endosomal pathway, like exosomes have become. The dominant process resulting in the generation of exosomes via the endosomal pathway in eukaryotic cells in part employs generic intracellular mechanisms of vesicle formation. This involves an early endosomal pathway for deriving exosome vesicles by pinching off of these intracellular endosomal membranes into an expanding intracellular space at the cell periphery called a multiple vesicular body (MVB) or the recently renamed multi vesicular endosome (MVE) . FinallyThe consideration of the evolutionary origins of EVs like exosomes gives insight into their present unusual properties that are very different than their producing cells ,26,27 anCompared to the generation of MVs, the dominant process of endosomal exosome EV formation and extracellular release that is described above is found progressively in all species, including ancient archaea ,31, currThe evolution of such intercellularly communicating vesicles likely was preceded by successful competition via natural selection for fitness compared to other early cells without such capacities. In modern organisms, their descendent relatives, EVs-like exosomes and micro vesicles, in fact comprise the principal means of performing the essential functions of intercellular genetic communication. Other less emphasized pathways to accomplish this include non-exosomal RNA carriage via chaperones like argonautes ,43,44, oThe first prokaryotic bacterial cells may also have emerged, from the proposed RNA polynucleotide containing ancient vesicle pro cells. These are thought to have evolved to retain subcellular exosome-like and MV-like outer membrane vesicle (OMV) particles by a natural selection preference. OMVs are individually generated in bacteria by ballooning out of their external membrane and then pinching off of these EVs at the bacterial surface like later MV but from the surface of eukaryotes ,48. In tIn addition, the MV-like OMVs have membranes that contain very important bioactive molecules important to innate immunity like lipopolysaccharide (LPS) that can induce local and systemic inflammatory response syndromes . The conOther uses of OMVs in bacteria like exosomes in higher species include their ability to mediate the horizontal transfer of genetic information ,73,74. TIn addition to the OMV transfer of genetic information like RNAs to mediate epigenetic effects, there can be important genetic exchange to other bacteria , like usExosomes are fundamental natural, universally produced, and physiologic nanoparticles of life. Compared to artificial, human-engineered nanoparticles, they can readily cross the blood–brain barrier ,96,97 byCompared to artificial engineered nano particles, it is of great importance that exosomes naturally and easily can evade the reticuloendothelial system . FurtherIt is postulated that there are subsets of modern-day exosomes with special properties reflecting their ancient origins that come from particularly activated cell donors and have membranes composed of unusual lipids. It is proposed that these lipids likely account for some properties of such particular exosome subsets. One outstanding property is survival under harsh conditions, including strong acid/digestive enzyme environments like in the stomach ,101,102,(a). Dietary milk exosomes can survive the harsh acid/enzyme environment of the stomach. Overall, some EVs, such as activated exosomes, can play special newly recognized biologic roles under harsh conditions. An important example is the unique ability of some exosomes to function in mothers’ milk for neonatal gastric passage. Exosome survival in milk is due to unusual resistance to the highly acidic pH of even 1.0–4.0, combined with the strong mixture of digestive enzymes that neither cells nor artificial exosome-imitating engineered nanovesicles can survive [ survive ,101,102. survive ,108,109.This powerful example allows for the stomach passage of orally administered exosomes in mothers’ milk and in dietary cows’ milk for subsequent absorption in the neonatal small intestine ,110. TheBy this means, it is likely that the immunoregulation of responses to foreign food antigens (Ag), that are relevant to the development of atopic allergies, are enabled , as are Furthermore, separate from milk issues and very important for current day EV treatments, we must also consider the survival of therapeutic exosomes after oral administration via resistance to the strong acid/enzyme mixtures of the stomach . In our (b). Tissue hypoxia is another prominent harsh condition that natural exosomes readily can resist. This is a further example of resistance to yet other harsh conditions, that we postulate have come from antecedent abilities gained in the toxic primordial ancient environmental conditions [nditions . Most ounditions ,104. Sucnditions , ovary [nditions ,133 prosnditions ,135,136,nditions , in whicA useful example of the hypoxia resistance properties of some exosomes involves those produced by mesenchymal stromal cells (MSCs), which now are seen as superior for therapy compared to their parental cells . Their u(c) The acid/enzyme microenvironment of intracellular phagolysosomes may be resisted by exosomes taken up by targeted cells. As we noted previously, the resistance of exosome subsets in dietary milk to the strong digestive mixture of gastric enzymes in high acidity may relate to their preserved actions in the frequent low pH of cancer microenvironments. There is similar resistance at other sites of profound inflammation or necrosis and the correlative finding that the in vitro cell production of active exosomes can be optimal at the highly acidic pH of 3-4 [H of 3-4 . Indeed,To this point, after exosomes are intracellularly taken up in targeted cells by phagocytosis  or microfluorescent membrane markers (red) and a phagolysosome enzyme (blue) in normal cell recipients. There was a clear demonstration of the stable simultaneous presence of the exosomes in the phagolysosome determined by dual-color imaging. Thus, this particular exosome subpopulation, postulated to be activated with unusual resistant membrane properties, can persist in phagolysosomes to possibly provide, over time, entirely distinct new mechanisms of the intracellular release and effects of functional cargo-like miRNAs inside the acceptor cell for uniquely affecting intracellular functions. Observed slow drifting diffusion in the local cytoplasmic microenvironments after the uptake of exosomes is consistent with such alternate intracellular release mechanisms [Especially instructive was the very thorough recent study employing the most sensitive intracellular visualization technique of single molecule-based super resolution microscopy . This enchanisms .Of course, it cannot yet be determined if the visualized exosomes are a subpopulation not able to release their contents while companion transferred exosomes that already released their contents have dissolved and thus cannot be seen. The occurrence of this potential, protected, low-dose dynamic exosome intercellular release may pertain to some unusual findings that biologic function can be transferred by very few exosomes that seem to contain minute amounts of the relevant miRNA beyond currently accepted low level limits for function ,178,179.(d) Summary pertaining to current exosomes as evolved from primitive ancient nanovesicles. According to these experimental-derived and hypothesized ideas, the family of EVs may have emerged before cells and had many valuable properties that have carried on to the present time, or might have arisen again via convergent evolution. With the subsequent emergence of eukaryotic cells, mitochondria were retained as intracellular bacteria for energy metabolism and further can release their own OMVs used for intracellular communication [nication ,183,184,nication ,186, andnication . In an aAs noted, this discussion of exosome primordial origins is based on current experiments and added hypotheses. These ideas emphasize the potential long biologic evolution of exosomes over billions of years of Darwinian experimentation via the natural selection of optimal properties to achieve current day physiological nanovesicle exosomes ,189. HerSome subpopulations of current day exosomes have membranes with unusual attributes. postulated to reflect properties descended from their pro cell ancestors that arose in the ancient, harsh, primordial environment that closely followed the origin of life. These unusual properties of these “activated exosomes include ability of some exosome membranes to allow binding of antibody-derived free light chains (FLCs) and further ability to associate with the miRNAs. Thus, pertinent to this review, the membrane properties of such activated exosomes described above also include resistance to the harsh acid and digestive enzyme conditions of the stomach. It has been shown experimentally that this allows for oral therapeutic exosome treatment with the antibody Ab FLC-coated and -selected miRNA-carrying exosomes described above to be able to systemically mediate in vivo the Ag-specific and miRNA-150 genetic-specific suppression of T cell immune responses in immune-targeted acceptor cells in the skin ,191.As noted, these unusual properties are postulated to be at least in part due to the unusual membrane lipid composition of the “activated exosomes” that is very different from that of the membranes of the activated host exosome vesicle-producing cells. The unusual membrane lipid composition of some current exosomes postulated to be derived from their ancient origins can result in an increased size and, most importantly, a distinctly greater viscosity and stiffness ,13. Duripos suppressor T cell-derived exosomes that are a subpopulation that differs from exosome cohorts derived from normal donor non-activated cells [In the high dose Ag-induced immune tolerance of mice, there are induced Ag-specific CD8ed cells . They caed cells . They caed cells ,191. Theed cells ,191.We call this special subset “activated exosomes,” because they are induced by a variety of in vivo immunization stimulations of the donor cells. We have found that such “activated exosomes,” that we propose have special membrane lipid constituents, are able to surface absorb immunoglobulin Ab FLCs but, interestingly, not Ab heavy chains nor whole IgG antibodies ,191,192.A crucial finding was that we established that activated exosomes, from the T cells of Ag-tolerized animals expressing Ag-specific FLCs and transferring associated miRNA-150, were involved. As proof of principal, we then tested a natural exosome construct model that recapitulated these properties. We found that trivial skin Ag-induced immunization induced immune B1a B cells that produced exosomes with the activation and Ag-specific Ab-coating within days. Then, by adding miRNA-150 via mere in vitro association at 37 °C, we created the B1a cell-derived exosomes with the same in vivo suppressive properties ,128,191,RNA interference (RNAi) is a biological process in which endogenous or exogenous added RNA molecules can inhibit gene expression by intefering with translation via neutralizing targeted mRNA molecules. The discovery of RNA interference (RNAi) led to new potential means of treatment via gene regulation and was touted as having enormous clinical potential for treating various disorders. However, there have been continued failures to treat patients via RNAi by employing artificial nanoparticles despite the original high hopes. It was anticipated that the intracellular delivery of artificial nanoparticles carrying siRNA or miRNA, possibly via viral vectors, would prove to be easily achievable. Despite this original optimism and much work and money, many relatively unsolvable problems developed, thus leading to diverse current and justified doubts about whether large scale efforts to create artificial nanoparticles to deliver genetic therapies should go on.However, sadly, in the face of numbers of failures, there continues to be significant large-scale funding by pharma and NIH to support increasingly complex ideas to deal with the problems of using artificial non-physiologic nanoparticles that, compared to natural EVs-like exosomes, are attempts to “build a better mouse trap” than “mother nature,” i.e., evolution by the natural selection over eons of the most optimal life forms. Continuous new plans for developing artificial nanoparticles usually result in attractive proposal diagrams of complex human-conceived and engineered vesicles with placed appendages for special effects. However, in the vast number of instances, although in vitro and animal results can be encouraging, these have not turned out to be very clinically useful for the in vivo delivery of small RNAs and other desired contents to patients. Thus, as before, they continue to be inferior to natural EVs, such as natural exosomes, that need far less adjustments for particular in vivo uses.incompatibilities that really should have been expected given their foreign nature. Some problems were new toxicities that led investigators to apply new artificial alterations to overcome these. Thus, artificial adjustments have often been applied to artificial concepts. It seems to not be realized that each artificial adjustment likely brings new side effects to deal with.This should have been anticipated. However, it was not. Instead, early high-profile publications created expectations that this challenge could easily be overcome for RNAi. This was too optimistic, since in no way could these artificial nanoparticles mimic the superior properties of natural physiologic EVs, such as exosomes. These natural nanovesicles likely developed over billions of years of progressive trial and error adjustments of evolutionary natural selection to achieve the current day fitness of near optimal design and capabilities ,189,190.Despite these continued failures, the literature is still crowded with proposed artificial nanoparticle variations favorably judged by appealing diagrams rather than biocompatibility. Scores of FDA-approved artificial therapeutic nanoparticles have been developed, with few reaching realistic clinical use and effectiveness. A liposome-based artificial nanoparticle was first developed nearly 25 years ago, but it is still struggling, as have many liposome-based imitations of exosomes ,194,195.However, despite some protection from the RES, PEGylation (the linking with synthetic polymer poly-ethylene glycol) was found to cause the loss of their long circulating properties due to enhanced blood clearance ,197. Thitoxicities other than rare careless preparation.In contrast, such an immune response problem is unknown for exosome therapies that, in fact, produce few, if any, significant side effects ,202. ComThis ignorance of the immunizing capacity of these artificial nanoparticles due to expected development of “natural,” Ag-specific, IgM antibodies  is typicFurthermore, these Ab responses led to classical complement activation due to the classical IgM complement-activation via these Ab coating the liposomes, and further there also were exosome surface alterations that led to the activation of the alternate complement pathway ,209. SucThese are all disasters for the immunologically unaware. Thus, there was not only a lack of achieved positive therapeutic constructs, but also the creation of clinically toxic negatives with these human bio engineer-conceived artificial nanoparticles. In contrast, natural exosomes are not bound by antibodies, complement, opsonins nor coagulation factors in the circulation or the tissues. Furthermore, surface tetraspanins universally present in exosome membranes with other natural natural adhesins are quite ancient and can mediate the physiological targeting of acceptor cells by interacting with their corresponding surface glycoproteins .Enduring enthusiasts of the artificial nanoparticle approach persist despite the ever-increasing doubts and growing published skepticism ,212, whoStill, workers and reviewers in the field talk of many adjustments to liposome-based therapy to achieve more useful results, even after so many years of trying, while simultaneously ignoring the elephant in the room, i.e., the superior therapeutic activities of exosomes, the natural EVs . TherefoRegarding the literature on artificial nanoparticles, it is clear that there is a vast potential in various fields with many avenues to explore, resulting in many accumulated papers have that continue to increase. There are never-ending claims about some great newly engineered nanoparticle able to deliver small therapeutic RNAs, often especially fashioned to target cancers. However, none of this has proven to be clinically successful . A very Nanoparticles, once injected into the body, face both physical and biological barriers  that affect the percentage of administered nanoparticles reaching the target diseased tissue and finally cells. In comparison, natural exosomes suffer none of these deficiencies. Exosomes have inherent semi-specific surface receptivity for the targeted cells controlled by the producing cell as important carrier effects facilitating delivery and further carrier effects that influence intracellular pathways to enhance the delivery of bioactive, pertinent, and selected RNAs that artificial nanoparticles could never replicate ,217. OveThe mentioned about cancer-targeting was of publications over the 10 years of 2006–2016 . It showFurthermore, there are severe bioengineering constraints of this approach with much wasted effort and money. Even if this technology could be developed, the dollar cost of delivery would be a huge barrier. If the price of current cancer drugs is expensive, added artificial nanoparticle cancer delivery would only be chosen for wealthy patients, not those of lower socioeconomic classes. Additionally, the toxicity of artificial nanoparticles could be a massive issue that is rarely discussed ,212,218.The analysis of delivery includes pertinent questions about how nanoparticles get out of blood vessels or extravasate into tumor tissue. The dominant view is that this happens through leaks in the tumor vasculature due to gaps between endothelial cells, that is thought to be a characteristic of cancers. However, this may be mistaken, and other processes need to be investigated given that trans postulated endothelial cell pores are difficult to demonstrate.In contrast, exosome experiments clearly show inflammation-augmented and even normal trans endothelial cell passage into the tissues in this physiological case-like the well-known ability of exosomes to pass across the blood–brain barrier ,212 and For exosomes, delivery and systemic in vivo alterations for specific cell targeting, with long duration, physiological uptake, and natural intracellular processing can favor effective small RNA intracellular release and biologic actions. The natural functional universality of exosomes depends on many unique biologic characteristics that are frankly impossible to reproduce in artificial nanoparticles. This means that such human-designed constructs are always fated to fail from the start in attempts in to imitate these numerous natural exosome aspects.Many investigators are still erroneously propelled to create artificial nanoparticles to replace exosomes that we stress are naturally derived from progressive, optimizing adjustments over billions of years of evolution. This weakness of artificiality is recognized as a false idea by many others who have found that more meaningful results come from the focused use of natural exosomes or altered natural exosomes ,227,228.(1)As natural nanoparticles, exosomes provide an effective avoidance of uptake by the RES .(2)They thus have a long in vivo duration of action, i.e., for several days after systemic administration of a single physiological dose ,191 comp(3)Exosome surface molecular signatures consist of ligands that bind particular surface receptors on acceptor cells ,163, as (4)Exosomes resist the harsh stomach acid/enzyme milieu ,128,191 (5)Exosomes have a natural ability to cross the normal, unperturbed blood–brain vascular barrier ,96,97 by(6)Exosomes have diverse biologic carrier properties. These include aiding transfers of contained RNAs via surface signatures for specific binding and then subsequent targeted cell surface, leading to postulated, carrier effects on intracellular biologic processes that influence subsequent RNA intracellular delivery and resulting epigenetic alterations in the function of the acceptor cells .(7)There are important questions about the lack of homogeneity among exosome preparations by those aiming at FDA approval. However, an essential property of exosomes is their great variability and it is likely there are a huge number of exosome subsets  that imp(1)Artificial nanoparticles cannot pass the blood–brain barrier ,211,212.(2)Artificial nanoparticles have an inability to cross endothelium, cell, and tissue barriers ,226,243.(3)Artificial nanoparticles do not pass the RES ,194.(4)Thus, artificial nanoparticles need a mere one pass circulation duration.(5)PEGylated stealth liposomes induce natural B1a B cell Ab responses ,207,244.(6)These Ab responses activate complement ,209 and (7)Then, complement C5a can cause a high incidence of hypersensitivity reactions ,199,205.(8)These reactions require steroid and anti-histamine co-treatment to ameliorate natural reactive host rejection responses .(9)The enhanced blood clearance of PEGylated stealth liposomes allows them to avoid the RES ,197 but (10)Artificial nanoparticles have a lack of surface tetraspanins for targeting .(11)There are no examples of dual, specific chosen targeting like Ab coating and selected small RNA transfers.(12)Artificial nanoparticles have a poor penetration of solid tumors ,195,213 (13)Artificial nanoparticles cannot be biologically activated.(14)Artificial nanoparticles do not recapitulate the unique complex lipid membranes of natural exosomes that allow for chosen Ab FLC binding and selected miRNA association to achieve dual Ag and gene-specific therapeutic targeting.(15)Artificial nanoparticles require years of unsuccessful adjustments to achieve liposome-based therapy ,205,215.(1)Research has demonstrated the unique dual antigen and gene specificity of immune T cell or B cell-derived suppressive exosomes ,191,192.(2)There is a revolutionary ability to administer exosomes via the nasal route. These exosomes then traffic around cranial nerve I fibers for smell, via the cribriform plate of the skull, to transit into the brain for the treatment of neuro-inflammatory conditions , like mo(3)The known ease of RNA loading of exosomes by multiple means ,250,251 (4)The ability of exosome surface-expressing ligands or receptors like those for growth factors like epidermal growth factor (EGF) to target EGF-R-expressing tumor cells , as well(5)Applying specific surface peptides to exosomes enables the binding to specific organ receptors to deliver chosen siRNAs ,256.(6)This kind of application can also allow for the delivery of synthetic DNAs ,258 and (7)One can generate exosomes that are mini-APCs (antigen-presenting cells) to act as strong vaccines that are useful against cancers ,263,264 (8)The exosome delivery of specific miRNAs is now possible ,270, esp(9)Exosomes are easily constructed for the therapy of genetic abnormalities, e.g., Huntington’s disease ,274,275,(10)Furthermore, there is a vast amount literature showing the treatment efficacy and safety of MSCs, which have recently been realized to be due to their released exosomes , as we h(11)Exosomes seem to be involved in the ability of young individual blood to rejuvenate old recipients ,287,288,(12)In cancer, CAR exosomes derived from effector CAR-T cells have potent anti-tumor effects and low toxicity ,291, tum(13)In COVID-19, therapy with MSCs and convalescent plasma must consider exosome involvement, with the suggestion that exosomes in convalescent plasma antagonize the weak immune antibodies . CapricoThe unusual biological nature of exosomes makes it possible to produce general therapy due to the genetic mismatch between human donors and patients. There also appears to be immune tolerance to exosome therapy from different species like in cows’ milk and even across kingdoms, i.e., from plants . If therWith exosomes, the difficulties of host detection and the elimination of the artificial exosome-like liposomes via the RES do not occur. Certainly, the mechanisms of the Ab FLC surface binding and miRNA association with activated exosomes have to be determined. Furthermore, if recurrent pulsed exosome therapy is needed, our recent discovery of effective oral administration can be employed ,191. TheExosomes are natural physiological nanovesicles with ability to mediated intercellular transfer functions in all species. They likely are involved to some extent in all intercellular interactions. This is principally via the transfer of non-coding RNAs to epigenetically influence specifically targeted cells by modulating their DNA expression resulting in altered cell functions. As likely derived from antecedent ancient vesicles generated near the origin of life in the primordial seas, or separately arose by convergent evolution, they have great resistance to various noxious environments. These include the acid/enzymes of the stomach, intracellular phagolysosome digestion, and the hypoxic microenvironment of cancers or others necrotic tissues. Such resistance seems due, in part, to the unusual membrane lipid composition of exosome subsets from particularly activated cells that also can allow for the binding of Ab FLCs and association with functional miRNAs.Therapy with exosomes as intracellular organelles has expected complexity. Their great heterogeneity is viewed as an advantage because there are many ways to profitably use native natural exosomes and their extracellular targeting properties, and also their non-canonical intracellular pathways to achieve genetic modifications that can optimize the functional effects of targeted cells that have notably yielded quite amazing results thus far. Alternatively, treating with homogenous, artificially engineered nanoparticles is old thinking from prior concepts that were developed for therapies based on conceptualizing exosomes as drugs, when they are actually complex biologic intracellular organelles. As such, they are therapeutically more like corticosteroids with multiple actions compared to more focused drugs like specific histamine receptor antagonists with a limited number of actions. Thus, for native exosomes, their complexity is actually a natural therapeutic advantage. Exosome treatments promise an easily achieved and far greater therapeutic index compared to the myriad of problems faced by artificial nanoparticles that includes new toxicities, biologic insufficiencies, and general ineffectiveness difficult to solve.


Influenza is an important research subject around the world because of its threat to humanity. Influenza A virus (IAV) causes seasonal epidemics and sporadic, but dangerous pandemics. A rapid antigen changes and recombination of the viral RNA genome contribute to the reduced effectiveness of vaccination and anti-influenza drugs. Hence, there is a necessity to develop new antiviral drugs and strategies to limit the influenza spread. IAV is a single-stranded negative sense RNA virus with a genome  consisting of eight segments. Segments within influenza virion are assembled into viral ribonucleoprotein (vRNP) complexes that are independent transcription-replication units. Each step in the influenza life cycle is regulated by the RNA and is dependent on its interplay and dynamics. Therefore, viral RNA can be a proper target to design novel therapeutics. Here, we briefly described examples of anti-influenza strategies based on the antisense oligonucleotide (ASO), small interfering RNA (siRNA), microRNA (miRNA) and catalytic nucleic acids. In particular we focused on the vRNA structure-function relationship as well as presented the advantages of using secondary structure information in predicting therapeutic targets and the potential future of this field.  Influenza is a significant research subject for scientists around the world due to its serious threat to public health. Generally, influenza A virus (IAV) is a human and animal pathogen causing seasonal epidemics and sporadic pandemics resulting in high morbidity and mortality. It is estimated that due to the Spanish flu in 1918/1919 up to 100 million people died .The IAV belongs to the Orthomyxoviridae family of enveloped viruses. Its genome consists of eight negative-sense viral RNA (vRNA) segments that encode for 11 proteins including glycoprotein hemagglutinin (HA) and neuraminidase (NA), a nucleoprotein (NP), two matrix proteins (M1 and M2), three polymerase complex proteins: polymerase basic protein 1 (PB1), polymerase basic protein 2 (PB2) and polymerase acidic protein (PA) as well as four non-structural proteins  . HA and The vRNA is replicated into positive-sense complementary RNA (cRNA) and transcribed into viral messenger RNA (mRNA) inside infected host cells. The vRNA and the cRNA are shielded with viral NP. In viral particles, the vRNA is associated with the polymerase, consisting of three subunits: PB1, PB2 and PA . The vRNThe viral RNA is involved in many processes through activities which relate to its secondary and tertiary structures. The correct packaging of all eight vRNA segments into one viral particle is suggested to be conferred at least partially via structured RNA motifs of vRNA protruding from vRNP. Within the viral particles, the vRNPs present a highly flexible double helical structure, with the polymerase at one end and a closing loop at the other . It is kThe segmented nature of IAV RNA serves as a good target for potential new antiviral strategies. Due to the high genetic variability of the influenza virus and the ease of its transmission, protective vaccination and anti-influenza drugs currently used are not fully effective. Therefore, there is a necessity to search for new approaches to limit the influenza spread. These days, the only anti-influenza drugs approved by the FDA are small ligands that bind to the surface of glycoprotein neuraminidase. Previously used ion channel M2 inhibitors are no longer recommended in therapy due to the emergence of the resistant strains . Antigenic shift and drift as well as adapting mutations allow the influenza virus to effectively evade host immune response. Since the variable nature of the influenza virus makes development of an effective vaccine challenging, its formula must be changed seasonally. Moreover, it cannot provide protection against future pandemic strains . This suThe design of currently used therapeutics is based on the prediction of a three-dimensional structure of viral proteins and interactions between potential inhibitor and protein(s). Intensive crystallography, cryo-EM and computational studies have provided new insights into secondary, tertiary and quaternary structure of the influenza proteins and the potential inhibitory small molecule ligands ,17,18. HAs an alternative, advances in primary and secondary RNA structure determination have led to the development of novel and effective anti-influenza agents. RNA-based approaches can potentially restrain spreading of the infection by interacting with vRNA, cRNA or mRNA ,10,19. TSequence and structural motifs of influenza RNAs are partially conserved between strains due to the combination of evolutionary constrains. Therefore, various oligonucleotide tools are designed to alter RNA expression and function, thus allowing to influence processes beyond protein or receptor involvement ,23. TheyAntisense oligonucleotides (ASOs) are synthetic, single stranded, short (12–30 nucleotides long) DNA or RNA fragments. They selectively bind to complementary regions and block target genes by several different mechanisms. Based on their mode of action, ASOs can be divided into three main groups: steric blockers of translation, modulators of splicing and recruiters of protein factors  that lead to the degradation of target RNA. The functions of target RNA as well as the selected interaction site determine the modulatory effect of ASOs . Thus, t2 nanoparticles, which allowed a complete replication inhibition of different influenza subtypes in MDCK cells [Liposomal encapsulation was used to deliver ASOs binding to functionally important sequences of packaging signals at the 5′-ends of PA and PB1 segments . AlthougCK cells ,32. In cCK cells ,32 in coCK cells .Currently, most antisense strategies involve particular ASO binding only to one target in the viral genome. Innovative approach was investigated by Duan et al., who designed the universal phosphorothioate antisense oligonucleotide, specific for the 5′-terminal conserved sequence found in all eight vRNA segments of the influenza virus . In MDCKAnother specific delivery strategy in influenza treatment was developed by Zhang et al., who conjugated single chain variable fragment (scFv) directed against influenza HA antigen with truncated protamine (tP) ,33. ASOsThus far, most studies on the ASO strategy towards the inhibition of the influenza proliferation have been reported as successful in both cell culture and animal models. Radavirsen (AVI-7100) was the first and currently only ASO in influenza treatment that entered clinical trials. Radavirsen is a 20-mer PMOplus®-based ASO, designed to bind highly conserved regions responsible for splicing M1 and M2 transcripts of M (+)RNA segment. The initial experiments in preclinical ferret, mouse, rat and monkey models revealed the antiviral activity of ASO and allowed to assess its toxicity. Next, a single and multiple ascending dose phase I clinical study was conducted in healthy volunteers. Since Radavirsen was well tolerated with no safety concerns identified, the results obtained by Beigel et al. are promising for the use of oligonucleotide drugs in influenza therapy ,36.Recent advances in ASO chemistry and delivery methods have led to the discovery of various promising candidates for influenza treatment. Remarkably, preventing viral proliferation with the ASO strategy has been achieved by targeting other elements than influenza RNA segments, including host-encoded hemagglutinin-activating protease TMPRSS2  and lympSmall interfering RNA (siRNA) is an oligonucleotide approximately 21–25 nt long formed through intracellular Dicer enzyme cleavage of the excises of exogenous double-stranded RNA. The siRNA induces sequence-specific degradation of targeted mRNA and can specifically inhibit the replication of influenza virus . In geneIt has been shown that synthetic siRNAs can specifically silence the influenza virus mRNA and inhibit the virus replication at different levels . Ge et aAn interesting observation was made by McMillen et al., who described that the NS1 gene-specific siRNAs caused decreasing mRNA level, while in case of siRNAs targeting NA and M genes, mRNA and protein expression levels were upregulated in culture lysates . This caGiardia intestinalis Dicer and evaluated the efficacy of these molecules in preventing viral infection in human primary monocyte-derived macrophages and dendritic cells. These siRNAs contained more than 100 different antiviral RNAs targeting the most conserved regions of the IAV genome. Results revealed that the replication of different IAV strains was significantly inhibited by IAV-specific siRNAs. The authors observed an increase in inhibition of viral RNA expression by up to seven orders of magnitude and a reduction of IAV protein synthesis as well as virus production. This research showed that the wide antiviral spectrum makes the siRNA a potentially efficient tool against multiple strains of influenza virus, acting by targeting their conserved gene regions [Recently, it has been demonstrated that siRNA molecules can efficiently inhibit the replication of human seasonal and avian influenza viruses in various types of human cell systems . Jiang e regions . Interesting research has been conducted by the Vasin group, who developed a highly effective hybrid microcarrier system for the delivery of antiviral siRNA mixtures . They usTo summarize, on the one hand, the siRNAs have high specificity, strong selectivity and silencing efficiency. Therefore, these molecules have been developed and used in the studies as antiviral tools against influenza, including highly pathogenic and avian influenza virus strains. On the other hand, siRNAs can be responsible for several problems, resulting in off-target effects. Hence, the current studies of the anti-influenza approach based on the siRNA-mediated RNAi process are limited to cells, chick embryos and animals and have not yet entered clinical trials.MicroRNAs (miRNAs) are small noncoding RNAs that control the translation and transcription of its target genes. These molecules can also regulate various biological processes, including viral infection. Emerging studies indicate that the host miRNAs play an important role in the intricate host-pathogen interaction network ,47. CellThe Kumar group presented that the miRNA-485 (miR-485) can regulate antiviral immunity and restrict viral replication via targeting host and influenza virus transcripts . They deIn 2017, Peng et al. reported that the endogenous miRNAs mediate antiviral defense against IAV . They scPrevious studies revealed a novel antiviral miRNA targeting the NS1 of the pandemic human influenza virus strains . BavagnoApart from the miRNA-based tools aimed at the target sequence of IAV genome, this approach can also be used to enhance biosafety of gain-of-function IAV research. For instance, tenOever’s group described a species-specific attenuation strategy, which allowed to restrict transmission in one species while maintaining transmission in the other hosts . The autCollectively, the examples of the studies described above indicate that host cells can lower their viral loads by controlling miRNA pathways, which may provide new opportunities for anti-influenza approaches. Investigation of miRNA molecules that directly target the conservative viral sequences can lead to the discovery of new therapeutics against influenza virus infection.Ribozymes and deoxyribozymes are two types of nucleic acids that have catalytic activity. Ribozymes have been shown to play an important role in biological processes such as splicing, RNA processing and replication of RNA genomes ,55. SomeDNA enzymes, also known as DNAzymes, were identified using in vitro selection methodology . Two DNAInteresting study by Kumar et al. presented a new approach by constructing siRNA-ribozyme chimera as a potential inhibitor for influenza virus . The desMotard et al. engineered ribozyme construct based on the hepatitis delta virus (HDV) and a specific on/off adapter (SOFA), which increases the specificity of the cleavage while reducing the non-specific effect . They prIn another study by Toyoda et al. reported the usage of 10-23 DNAzymes targeting the AUG initiation codon of PB2 mRNA of IAV . They prIn another study, Kumar et al. prepared modified 10-23 DNAzymes, targeting various regions of the M2 gene and testing their ability to specifically cleave the target RNA . The preInvestigations described above indicated that catalytic nucleic acids could be a useful tool to control viral infection. The ribozymes and appropriately modified DNAzymes possess potent anti-influenza activity and can provide an opportunity to enhance the ASO strategy. In fast-evolving viruses, such as influenza, the development of effective therapeutics to limit disease spread is challenging. ASOs, siRNAs, miRNAs or catalytic nucleic acids tools afford the potential tractable strategies to eradicate the influenza virus. It is because they are easy to design, can be chemically modified to improve their stability and are directed against multiple virus strains by targeting the most conserved RNA regions. However, these tools act in a sequence-specific manner, which makes these approaches not highly effective in inhibiting the proliferation of influenza virus. Hence, the designing and development of new inhibitory oligonucleotides should be based on additional criteria using knowledge on the viral RNA secondary structure. As previously mentioned, influenza virus genome is organized into eight segments of single-stranded viral RNA. Each segment is composed of conserved, partially complementary 5′- and 3′-ends, segment-specific untranslated regions (UTRs) and open-reading frames (ORFs) . During The secondary structure of vRNA is an important regulator of virus biology, because it plays a role in assembling the different vRNPs into infective virions and in directing reassortments between IAV subtypes. The terminal fragments at the 5′- and 3′-ends of the vRNA segments  nucleotides.In order to inhibit viral proliferation, Lenartowicz et al. used information about secondary structure of protein-free (in vitro) influenza A genomic segment 8 (vRNA) to design ASOs . PredictA similar strategy for selecting ASO-susceptible RNA regions for another influenza genome segment was employed by Michalak et al. . A summaThe significant role of secondary structure determination preceding the design of sites available for ASO applies not only to the genomic influenza segments, but also to (+)RNA. In the paper published by Soszynska-Jozwiak et al., influenza virus segment 5 (+)RNA secondary structure was established and validated by bioinformatics and experimental studies . Nine ofOverall, the results revealed above illustrate strong correlations between the predicted ASO binding regions and the ability to inhibit influenza virus replication. However, in each study some ASOs targeting single stranded regions exhibited moderate efficiency. This can be due to the dynamic nature of the structure of influenza RNA segments. Additional reasons, including local structure stability as well as interactions with other RNAs or proteins, also contribute to the antisense potency of ASO in the cells (in vivo). Nevertheless, besides playing an important role in designing efficient hybridization sites for ASOs, RNA secondary structure determination significantly contributes to understanding the influenza virus life cycle and replication mechanisms. The RNA structure-based target site selecting method provides novel prospects for other antiviral therapeutic agents such as small molecules.According to several publications, the RNAi efficiency is influenced by the target RNA structure ,90,91. TInteresting research concerning the inhibition of influenza viral replication by targeting structural motifs of vRNA has also been conducted by Kesy et al. . It is kAnother structure-based approach uses the ability of small molecules to target specific RNA structures. In general, small molecules have the potential to recognize and bind to RNA targets based on their secondary or tertiary structures. Bottini et al. reported specific recognition of the vRNA promoter region (panhandle structure) by small molecules as a potential novel drug target and tool against IAV infection . The autIn summary, we presented examples of studies concerning ASOs, siRNAs, miRNAs and catalytic nucleic acids approaches as potential antiviral tools against IAV. We described investigations that focused on the viral RNA structure-function relationship and genomic conserved RNA regions as targets for oligonucleotides strategies. Moreover, we also discussed a new criterion for choosing and designing target sites in IAV segmented RNA that is based on information about its secondary structure.Nowadays, given the large number of new imaging, sequencing and biochemical techniques, the influenza virus biology  is relatively well understood. Recent advances in next-generation sequencing (NGS) technology provide new insights into the IAV genome architecture . NGS tecHowever, an efficient oligonucleotide tools delivery to the target cell still remains a challenge. To promote the intracellular uptake, many effective approaches are being developed, including oligonucleotide chemical modifications, bioconjugation of various delivery-promoting moieties or usage of nanocarriers . In addiIn the last few years, the CRISPR-Cas system has become one of the most powerful gene editing tools. Interestingly, several studies using a CRISPR-Cas13-based strategy have been performed on potential inhibition of RNA viruses, including IAV  and the In light of the continuous evolvement of IAV and its increasing resistance to existing drugs and vaccines, finding target sites in IAV RNA that are sequentially or structurally conserved and less prone to drug resistance is a very important issue. That conclusion could be extended to other RNA viruses, including SARS-CoV-2. A novel therapy concerning the regulation of pathogenic RNA by using RNA-targeting strategies is still being developed. The flexible and dynamic nature of viral RNA structures is a challenge associated with targeting RNAs with potential therapeutics. Therefore, information regarding the molecular and structural basis behind influenza virus biology, including knowledge about RNA secondary structure, could be used to design and develop structure-based approaches that will inhibit influenza replication. The ability to identify oligonucleotides or molecules that specifically bind to RNA targets on the basis of its structure provides a viable path to create new drugs against influenza.


Interest in college courses that focus on aging attract a variety of students. For older adults, the decision to take college courses may be fueled by a desire to engage in life-long learning, finish degrees that have been long desired, or retool and change careers. Older adults 65 years and older living in Oregon may audit courses for free in four-year public universities. Older auditors and degree-seeking students often work closely with faculty in providing support on course projects and sharing developmental insights that stimulate discussions about aging pathways. This presentation outlines the ways in which older adults contribute to educational conversations, mentor younger learners, and enhance classroom/university environments. How older adult learners have provided support in workshops, aided students in career decision-making, connected students to community resources, and provided contacts for intergenerational community activities will also be highlighted.


Smartphone technology has enabled the creation of many working memory training (WMT) Apps, with those peer-reviewed described in a recent review. WMT claims to improve working memory, attention deficits, hyperactivity and fluid intelligence, in line with plasticity brain changes. Critics argue that WMT is unable to achieve “far-transfer”—the attainment of benefits to cognition from one taught context to another dissimilar context—associated with improved quality of life. However, brain changes after a course of WMT in frontoparietal and striatal circuits—that often occur prior to behavioral changes—may be a better indicator of far-transfer efficacy, especially to improve impulse control commonly dysregulated in those with addictive disorders, yet not commonly examined in WMT studies.via PubMed, Scopus, Medline, and Google Scholar.In contrast to previous reviews, the aim here is to focus on the findings of brain imaging WMT training studies across various imaging modalities that use various paradigms, published 35 brain imaging studies utilized fMRI, structural imaging , functional connectivity, EEG, transcranial direct current stimulation (tDCS), cerebral perfusion, and neurogenetic analyses with tasks based on visuospatial and auditory working memory, dual and standard n-back.via myelination and functional connectivity changes. Neural effects of WMT may persist months after training has ended, lead to non-trained task transfer, be strengthened by auxiliary methods such as tDCS and be related to COMT polymorphisms. WMT could be utilized as an effective, non-invasive intervention for working memory deficits to treat impulse and affective control problems in people with addictive disorders.Evidence suggests that repeated WMT reduces brain activation in frontoparietal and striatal networks reflective of increased neural circuitry efficiency  Working memory training (WMT) is a “do-no-harm” cognitive alternative  to existing psychotherapy and pharmacotherapy for various impulse control deficits  . It is pthrowing the baby out with the bathwater”) to consider other potentially effective measures. Furthermore, perhaps, the currently accepted definition of a far-transfer effect is too narrow, in that it does not consider how distant aspects of cognitive performance and behaviors  might enhance seemingly unrelated functions  which, in turn, impact quality of life , where interventions are currently ineffective for relapse rates. As such, marked changes in activity across areas of the brain associated with specific behavior changes could infer a positive treatment outcome and far-transfer effect. For example, those with addictive disorders who often demonstrate profound deficits in impulse control, show dysfunctional frontostriatal functioning  with impAccording to our recent review  CogMed  WMT has Similar reviews have criticized CogMed for not sufficiently substantiating claims that WMT improves attention and ADHD symptoms . FurtherThus, from the perspective of current reviews and meta-analyses of WMT, it appears that the field runs the risk of becoming at worst redundant and unable to make a sustained impact on the neuroscience of mental health and enhancement of cognitive ability . HoweverAgainst this background, with the view that there may still be validity in pursuing WMT for treating the neural processes underlying impulse control deficits, three points are considered in this review:Alternative approaches to measure the effectiveness of WMT across various training paradigms include brain imaging measures—such as structural and functional MRI—which appear to demonstrate neural changes often independently of behavioral changes that may occur later.WMT research has so far relied on measures of ADHD symptoms, working memory performance , and global intelligence/executive function improvements, which critics argue do not elicit significant far transfer effects , 47, 48.Measures of the neural correlates of impulse control in relation to WMT in those with addictive disorders , 37, 49 With these points in mind, the first aim of the current review is to examine all brain imaging findings across all peer-reviewed WMT paradigms since the first neuroimaging WMT study  to the pSee Thirty-five neuroimaging WMT studies were found using task-based functional magnetic resonance imaging , resting state fMRI (n = 2); structural imaging , transcranial direct current stimulation , electroencephalography (EEG), cerebral perfusion (n = 4). WMT neuroimaging studies found in this review utilized visuospatial and auditory working memory tasks, dual or standard n-back tasks .blood oxygen level dependency (BOLD). When an area of the brain is active, haemodynamic activity in the region increases, enabling fMRI to measure changes in neuronal activation , Salaya and colleagues in 2006  argue thIn another early fMRI study of WMT by Schneiders and colleagues in 2011  the neurAnother fMRI study by the same group examined the effect that WMT has on brain activation in relation to maintaining and improving cognition in older age . The autProgressing this work more recently, Heinzel and colleagues examined transfer effects to a multimodal dual task, to examine whether working memory can be improved in older adults (60–72 years of age), and whether transfer gains occur across visual and auditory modalities . In theiIn another case study in line with Westerberg and Klingberg’s study in 2007—using WMT alongside fMRI—a 38-year old man with glycogen storage disease type IV and memory complaints was given CogMed training . He compThe next fMRI WMT study was published more recently in 2019, examining the neural and behavioral effects of an adaptive online verbal WMT in healthy adults with a mean age of 56 years . The WMTIn another fMRI study published in 2019 , the effAnother 2019 fMRI study examined the effects of CogMed WMT on neural structure and function of children  born extremely pre-term  or born with extremely low birth weight . ChildreFinally, in the most recent fMRI study , there is some evidence for the contribution of the catechol-O-methyltransferase (COMT)  polymorphism (rs4680) to WMT related prefrontal cortex plasticity . This COIn summary, the fMRI studies of WMT reveal decreased activation after WMT training in frontoparietal, cingulate, insular and occipital cortex, regions, possibly indicative of either practice effects or increased neural efficiency, for example, greater encoding efficiency over the time course of training. In addition, an inverted-U shape relationship may occur during WMT, with increased activation in the right inferior frontal and right intraparietal cortices after 2 weeks of increased load n-back training shown, but with reduced activation during consolidation and after a month of training. Furthermore, improved connectivity associated with WMT-related increased activation in middle frontal gyrus and inferior/superior parietal cortices may indicate greater functional connectivity between regions. Moreover, while the debate continues about whether reduced or increased activation signals greater neural efficiency following WMT, it is also suggested that wider recruitment of frontoparietal regions during the course of training  is indicative of better neural functioning. Interestingly, pre-training striatal activation, and also older-age decline in striatal activation was shown to be related to reduce WMT transfer gains, and it appears that reduced activation in working memory-related brain regions most commonly reflects improved cognition, particularly in the left DLPFC, right superior frontal gyrus, bilateral supramarginal gyrus, bilateral middle temporal gyrus, and bilateral middle occipital lobe in adults. In addition, increased neural efficiency (reduced activation) after WMT in frontoparietal regions is typical of a “young versus older” response to training, with older adults’ WMT improvements related to more efficient DLPFC activation. Taken together, predominantly frontoparietal and striatal activation is associated with WMT benefits, but it is not clear whether increased or decreased activation is most significant, and how this differs in young versus older people.Three fMRI studies used functional connectivity analyses to examine how WMT might alter global and regional neural network activity—which is often universally consistent —during fMRI cognitive task performance . In the In summary, functional connectivity studies of WMT implicate improvements  within the ECN and dorsal attention network (DAN) in adults, but in children the ECN showed reduced connectivity following training, which may also be related to reduced reward processing in the younger group. Moreover, in an exploratory study of two participants, reduced local efficiency and increased global efficiency has been shown after WMT. These findings corroborate the task-based fMRI studies, in that both modalities implicate improvements in neural activation within prefrontal cortex networks following WMT, and while this does not demonstrate far-transfer , it is worth remembering that better working memory performance is associated with reduced impulsivity , 33.significant post-training improvements on CogMed tasks: Identification task speed and Groton Maze Learning accuracy increased.One pilot study of resting state fMRI (brain activation independent of task performance) used 25 sessions of 30- to 45-min CogMed training for children with neurofibromatosis type 1 . NeurofiA more recent resting state fMRI study using WMT examined the effects of computer-based training on functional connectivity of attentional networks in primary school children . The chiIn summary, the resting state fMRI studies link to the previously summarized fMRI studies, in that neural changes following WMT tend to occur in lateral prefrontal, parietal, and basal ganglia regions, and in these two studies to date, it appears that increased resting state activation in the attentional networks is associated with greater working memory efficiency, whereas the task-based fMRI studies show both increased and decreased activation associated with cognitive efficiency.Structural imaging techniques capture the tomography  of different regions of the brain, often through nuclear magnetic resonance which generates high resolution images . In six In another structural study, Envig and colleagues examined the plasticity effect of WMT on cortical thickness and volume in 42 male and female participants who were on average 60 years of age, after 8 weeks of intensive training using memorization techniques of location sequences throughout a person’s house . It was Another structural study examined the dynamics of the human structural connectome underlying WMT . It was In another structural brain imaging study of WMT using MRI and voxel-based morphometry, in-patients with chronic methamphetamine use who were abstinent for at least one week prior to the intervention, were given 20 half an hour sessions over 4 weeks of the C-Ya App (based on 0- to 3-back of the N-back task), and were scanned at baseline and after 4 weeks . CompareIn another structural imaging study of adaptive WMT, white matter plasticity in the main frontoparietal tract, namely, the superior longitudinal fasciculus, compared to the cingulum bundle as a control, was measured in line with potential cognitive benefits . The autIn summary, structural brain imaging studies of WMT have demonstrated increased white matter density within the intraparietal sulcus and the anterior corpus callosum after training . Other studies found volumetric reductions in the bilateral frontoparietal regions and left superior temporal gyrus, which may indicate synaptic pruning underlying greater neural efficiency. In addition, increased cortical thickness in the right fusiform and lateral orbitofrontal cortex have been observed in people with an average age of 60, suggesting improvements in attentional control. And in line with fMRI studies, connectome analyses of mictrostructural changes after WMT reveal increased global integration within a frontoparietal attention network, indicative of greater neuronal efficiency. Moreover, in line with some fMRI studies, increased bilateral basal ganglia volume after WMT in people treated for methamphetamine addiction is associated with improvements in impulsivity and self-regulation. Finally, white matter plasticity  in the main frontoparietal tract, namely, the superior longitudinal fasciculus, compared to the cingulum bundle as a control, was shown to occur following WMT. Thus, in conjunction with fMRI studies, structural imaging studies confirm the involvement of frontoparietal and striatal changes following WMT.via electrodes across the scalp. Historically, tDCS was introduced to treat depression and other mood related conditions, but has since garnered attention due to some success delivering specific cognitive gains  to facilitate the depolarization or hyperpolarization of neurons, respectively. In the first tDCS WMT study, Martin and colleagues gave 10 sessions of dual n-back training with active or sham tDCS versus tDCS only  gene . The autIn another tDCS study, Jones and colleagues attempted to better understand how tDCS creates cognitive gains reflected in brain function when coupled with WMT . To thisIn the most recent tDCS study of WMT, the effects of neurostimulation on working memory function in older adults, with a mean age of 74 years, were examined . The stuIn summary the tDCS studies of WMT demonstrate that active tDCS appears to enhance participants’ working memory accuracy (but not skill acquisition). Moreover, online tDCS  appears to be associated with most significant skill acquisition, suggesting that conducting WMT alongside active tDCS might provide greater cognitive gains than providing “offline” tDCS . In addition, it appears that a greater level of stimulation  induces significantly greater far transfer gains. Genotype effects on the efficiency of tDCS during WMT show that the val/val versus met/met COMT genotype may gain the most from 1.5 mA tDCS during visual WMT and from 1 mA tDCS during spatial WMT. In contrast, for met/met polymorphisms, 2 mA may be related to poorer performance compared to 1.5 mA on spatial WMT. In terms of linking tDCS to neural activation, active tDCS improvement is linked to frontal-posterior alpha band activity, and theta and low alpha oscillations associated with greater neural synchronization. Similarly, in older adults, active versus sham tDCS increases connectivity between the left DLPFC and right inferior parietal lobe. As such, the tDCS studies appear to corroborate the findings of fMRI and structural studies, in that fronto-parietal activation is improved with stimulation.This technique is a non-invasive, electrophysiological imaging modality which captures topographical electrical activity direct from the cortex through electrodes on the scalp . Three eIn another EEG study by Oelhafen and colleagues , healthyIn the latest EEG event related study of WMT using dynamic causal modeling to examine effective connectivity changes, Chen and colleagues contrasted P300 with N160 amplitudes—the former associated with selective attention, the latter associated with detection of novelty in review and inhibitory control . The autEEG studies, in summary, have demonstrated that WMT benefits are transferred to other cognitive tasks in association with more efficient frontoparietal and parieto-occipital network connectivity—particularly the ECN and DAN—in line with findings from other neuroimaging modalities.This measurement examines the net pressure gradient leading to cerebral blood flow in the brain. One study has examined significant training effects after seven days of n-back WMT compared to an active control group in relation to changes in cerebral blood perfusion . WMT wasNeurogenetic analyses examine how genetic variation, including genetic mutation, affects behavior and cognition. Studies have shown that a genetic variation linked to increased dopamine metabolism in the prefrontal cortex  amplifies age-related alterations in working memory performance. Furthermore, in younger participants, the influence of these dopaminergic genetic polymorphisms is suggested to increase as working memory load increases. On this basis, a recent fMRI study by Heinzel and colleagues compared younger and older adults’ neural responses during 12 sessions of increasingly difficult adaptive n-back WMT . Firstlyval/val genotype). Other imaging studies have utilized structural measures, including MRI, voxel-based morphometry for volumetric analyses, shape and cortical thickness measures, and examination of myelination neuroplasticity changes in the “connectome” after WMT. In addition, some fewer studies have begun to explore the utility of brain stimulation measures  as an adjunct to improve WMT far-transfer effects that may translate into long-term behavioral changes. Other neuroimaging studies have used EEG and cerebral blood perfusion measures. Finally, the studies in this review have highlighted three debates within the WMT neuroimaging field: a) the pattern of brain activation underlying far-transfer, b) whether WMT is associated with increased or decreased neural activation, and c) whether there are differential neural changes with WMT in younger versus older participants.The first aim of this review has been met, to demonstrate that brain imaging studies of WMT report significant neural effects often independently of behavioral changes in frontoparietal and frontostriatal circuitry. This review has also met its second aim, to demonstrate that there is a paucity of far-transfer measures of impulse control in neuroimaging studies of WMT, despite a wealth of evidence emphasizing that frontoparietal and striatal circuits not only contribute to changes in working memory function across the lifespan but are also associated with the cognitive control of impulsivity , 91. As Various neuroimaging studies reported—alongside neural changes—far transfer effects of WMT to other un-related cognitive domains , 82, 87.The majority of fMRI studies have reported decreased activation following WMT , 60, 63.Other fMRI studies have reported increased activation following WMT , 61, 64.The significance of increased striatal activation and plasticity in the role of WMT transfer and effective training consolidation was particularly highlighted by two studies . Dahlin and colleagues conducted an fMRI study to examine whether overlapping neural patterns could predict the degree of transfer to an untrained cognitive task. They used an updating task (remembering letter sequences) to demonstrate significant transfer gains to the 3-back level of the n-back task (but not to the non-updating Stroop task), the success of which was mediated by pre-training striatal activation, which was not present in older adults . The autVal/Val genotype . As such, it is difficult to form a clear conclusion as to the consensus in the field, or to conduct a useful meta-analysis of WMT brain imaging studies—which will need to be reserved for such a time that a sufficient number of comparable studies can be analyzed with Activation Likelihood Estimation (ALE) for example . NeverthThe neuroimaging studies reviewed highlight a potential non-linear relationship between brain changes and far-transfer effects that may be shrouding the measurement of significant WMT benefits. Imaging studies show that training load, duration, modality, participant age, and even participant genotype can influence the effects of WMT on the brain. In addition, neural changes may only occur gradually and prior to the emergence of significant behavioral changes, hinting at the need for researchers interested in this field to control the impulse to throw the baby out with the bathwater, and to pursue other measures. This may be especially true when considering research into the neural effects of WMT for those with addictive disorders, whose enduring impulse control deficits tend to increase the likelihood of relapse. WMT is a “do-no-harm” intervention that—according to the studies reviewed here—may improve impulse control deficits associated with aberrant frontoparietal and striatal processes in people with addictive disorders.SB conceived and wrote the manuscript. RM-P created the table of studies. JT helped to substantially revise the manuscript. HS helped to revise the manuscript.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.https://www.frontiersin.org/articles/10.3389/fpsyt.2020.512761/full#supplementary-materialThe Supplementary Material for this article can be found online at: Click here for additional data file.


In this opinion piece derived from a webinar organized by the Radiological Society of North America and conducted in the spring of 2020 during the COVID-19 pandemic, leaders from three large North American and Asian academic radiology programs review the strategies employed at their respective institutions to address the impact of the pandemic on their departments. In the first segment, the author describes the approach taken in the radiology department at an 1800-bed Asian hospital system which focuses on the creation of capacity to accommodate over 5000 COVID-19 patients in early 2020, the sustaining of services during the surge, and the development of adaptive mechanisms to address future surges and pandemics. In the second segment, a large southwestern medical system addresses the creation of a long-term strategy to provide imaging services safely for staff and patients while simultaneously utilizing technology to maintain interprofessional connections. The final segment describes how a large multifacility health-care enterprise in the Pacific Northwest of the United States is developing strategies to successfully reemerge from the forced reduction in imaging services experienced during the COVID-19 surge in early 2020. Recovery and short- and long-terms strategic growth for radiology diagnostic and procedural services with COVID-19 in our communities and care facilities is a challenge for all radiology practices. Adapting local responses to the initial surge and sharing ideas for creating safe workplaces will enable radiology practices throughout the world to maintain critical patient access to the services Radiology departments and Radiologists provide. This manuscript builds on a webinar held on June 19, 2020 in which radiology leaders from Singapore and the United States share their COVID-19 experiences and provide strategies to address moving forward with persistent and new surges of COVID-19.1,2 We have employed three broad strategies for addressing the second surge and beyond: (1) build, (2) sustain and (3) adapt.Singapore General Hospital is the largest hospital in Singapore with approximately 1800 beds, diagnostic, vascular/interventional, and nuclear medicine departments and a staff of over 700. As of mid-June 2020, our system has cared for over 5000 COVID-19 patients. Previous experience with SARS has shaped our preparation for subsequent challenges.The first strategy is to “build” or create capacity before it is needed, including expanding the department footprint, securing more equipment and manpower, increasing operating hours and creating new workflows. For example, during the first surge, our emergency department expanded into an adjacent surgery center, under a pedestrian bridge and into a multistory parking garage. Our portable radiography service also expanded in tandem, utilizing a pre-built lead-lined radiography room in the garage. More recently, we built a ward in an open-air parking lot with 50 negative-pressure container rooms for additional capacity . To supp3The next strategy, to “sustain”, includes alternating work sites and adjusting work shifts. Supplies must be preserved by being more efficient and simplifying processes and imaging protocols that were unintentionally complicated. By observing our anesthesia colleagues who devised a clever telephone booth-style swabbing station, a team of radiologists, radiographers and anesthesiologists conceptualized and operationalized a new container booth X-ray facility where the radiographer remains isolated from the patient, thereby diminishing personal protective equipment consumption rates. Safe distancing and infection control requirements reduced the throughput of our imaging centers, so we fast-tracked a more nimble appointment system originally developed for our new hospital which entails a just-in-time appointment schedule that dynamically adjusts itself. Patients receive an updated precise appointment time, so that on arrival they proceed directly to be get scanned and then leave the facility. All pre- and post-scan issues are addressed via teleconsultation.The final strategy is “adapt”, as the department will need to activate reserves, reconfigure existing approaches, and adopt new rules. As the COVID-19 protocols and dedicated equipment remain in place, staff can be reactivated to provide the necessary support on short notice. Infection prevention and control measures also continue to adapt. With optimization of our processes, downtime for room preparation and CT scanner cleaning has been reduced from 5 h to under 2 h. Adapting also requires people to work outside of their comfort zone with some residents, radiographers, radiologists, nuclear medicine physicians and nurses redeployed to the ED, COVID-19 care facilities and even external sites to support the national response. Finally, we need to adapt to breaches in prevention as some staff will inevitably become infected with COVID-19. Even something as fundamental as how staff take work breaks must change .Workplaces and workforce flow adaptions during the pandemic should be governed by attention to the best available understanding of how COVID-19 is transmitted. Instituting measures to keep staff safe is of paramount concern. At Emory University, we utilize guidance from infection prevention leaders to operationalize a culture of safety. This includes flexing work hours and locations to deliver care while trying changes to meeting mission-centric goals providing patients access to the best, most necessary and appropriate care.2 The current understanding is that an infected person transmits live virus when in close proximity (within 6 feet) to an uninfected person. As the infected person coughs or sneezes, respiratory droplets containing the virus land in the mouths, noses or possibly the eyes of those nearby. Many of our workspaces, including reading rooms, modality rooms, control areas and interventional radiology suites are not conducive to proper distancing.To create safe spaces, radiology leaders must understand how COVID-19 is spread.4 Workspaces can be reconfigured by moving staff and trainees off-site and separating workstations in current workrooms to provide continuous care with fewer people in any given space  .Post-COVID-19 recovery requires a thoughtful plan to gradually resume imaging operations . We deplWhile radiology offers a broad array of imaging services, we have been strategic about our approach and focus. We established a steering committee to foster a strong team culture and alignment of imaging recovery efforts across the health system. Modality specific teams were deployed for top four imaging modalities and interventional radiology service, each comprised of a physician with domain expertise, operational lead, technologist, scheduler, and information technology personnel with representation from all service sites. While addressing the challenges from the pandemic, opportunities to build efficiencies in imaging workflow have been explored and kaizen ideas been proposed. Clustered scheduling, self-scheduling, and shorter MR protocols are being operationalized to optimize MRI capacity for improving access. Similarly, offering site-specific exam scheduling for screening exams and elective imaging studies at ambulatory sites can maximize efficiency, help standardize processes, and optimize quality while minimizing safety concerns. Reducing patient no-shows, same-day cancellations and leakage to outside facilities can ameliorate the challenges for meeting demand.Finally, organizations should explore select long-term opportunities to lower cost, improve access and optimize imaging workflow by investing in advanced information technology solutions and automations. Consolidation of imaging and interventional services and expanding hours of clinical services is a needed measure to lower cost and improve patient satisfaction. Departments should consider investing in mobile solutions for screening mammograms, ultrasound, CT and MRI based on patient referral, service needs and geography.Build capacity, sustain operations, and adapt to future pandemics.Create safe workspaces, remote workstations and flexible work hours to provide care.Take precautions including monitoring of staff and physical distancing to protect staff and patients.Employ online technology to maintain personal connections between colleagues, staff and patients.Redesign key processes to restore imaging services.Utilize information technology to provide operational metrics and dashboards and to track key performance indicators.Maximize safety and efficiency of radiology appointments using online scheduling with texting and e-mail for patient communication.Deploy teams to optimize modality and site-specific services.Explore opportunities to lower cost, improve access and optimize imaging services long term.


A rich combination of themes related to sport skills is presented by seven articles dedicated to perception and action characteristics of those skills. First, a perspective article by Paterson et al. analyze whether a task-irrelevant contextual information  would distract players while performing a soccer penalty kick. They confirm that kickers' attention was disrupted during their goalkeeper-dependent strategy, highlighting systematic, direction-specific effects of advertisement motion on aiming task. Kishita, Uedo, Kashino et al. examine effects of varying speeds of a task-relevant stimulus  on visuomotor strategies used in baseball batting; authors stress that eye-head coordination depends on ball speed, but regardless of it, predictive saccade and quick head movement were temporally linked to bat-ball contact and hip motion. Next, two studies explore different gaze strategies. In another article, Kishita, Uedo, Kashino et al. focused on eye and head coordination patterns used by elite baseball players during batting in-game situations. They highlight that top batters delay initial saccades to obtain slightly more time acquiring visual information, as well as they may use head (instead of eyes) direction to encode bat-ball impact location. Kato explores how expert kendo fighters use a particular gaze strategy  during in situ sparring practice in offensive, defensive, and real match situations. He emphasizes that kendo experts keep gaze calmly stable on opponents' face but use peripheral vision strategy to obtain information from their body movements. Finally, two sport articles refer to distinct aspects involved in visual anticipation and gaze training. First, Lüders et al. examine effects of knowledge of an opponent's action preference on anticipation performance and gaze behavior during defense of volleyball attacks. They highlight influence of contextual information on anticipation, while systematic changes in the number of fixations and the duration of final fixation unobserved in defenders when they had preference information. Second, Neugebauer et al. examine characteristics of focus of attention during a quiet duration training for darts throwing. Even with similar throwing accuracy, authors show that visually instructed groups increased quiet eye duration whereas the kinesthetic group decreased it, suggesting perceptual and motor learning processes are dyssynchronous.Following on from this conceptual discussion, six articles investigated the following sport modalities: soccer, baseball, kendo, darts, and volleyball. Two studies focused on effects of environmental stimuli on gaze dynamics and motor performance. Stuart et al. covers measurements of eye-movements in patients with mild traumatic brain injury, showing that there are no diagnostic criteria available for this injury. Next, Vargas et al. analyze body sway of sleep-deprived participants, highlighting that saccadic eye movements improve postural control even in sleep-deprived situation but are insufficient to avoid its deterioration due to sleep deprivation.This Research Topic concludes with three articles bringing interesting applications of eye movements research to the context of public health and active living. Properly timed gaze behavior is critical to control the movements during active living; eye movements support adaptive motor control. First, a review article by Baker et al. examine how individuals with Parkinson's disease perform walking turns with visual cues to promote anticipatory eye movements and, possibly, reduce the risk of falls. They emphasize that visual cue training is capable of changing from no anticipatory eye or segment movement to a pattern similar to that of neurotypical young adults, with craniocaudal rotation sequences during walking turns.Finally, a brief report article by The multiplicity of contents presented in this Research Topic is illustrative of the growing interest in gaze behavior in sports and related activities and should stimulate new and innovative studies. As eye-tracking technologies and other motion measuring systems improve and become more popular in this field, many inspiring ideas and challenges are available for those interested in investigating the role of eye movements in sport and active living.All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.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.