Primary liver cancer, consisting predominantly of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), remains one of the most lethal malignancies worldwide. This high malignancy is related to the complex and dynamic interactions between tumour cells, stromal cells and the extracellular environment. Novel in vitro models that can recapitulate the tumour are essential in increasing our understanding of liver cancer. Herein, primary liver cancer-derived organoids have opened up new avenues due to their patient-specificity, self-organizing ability and potential recapitulation of many of the tumour properties. Organoids are solely of epithelial origin, but incorporation into co-culture models can enable the investigation of the cellular component of the tumour microenvironment. However, the extracellular component also plays a vital role in cancer progression and representation is lacking within current in vitro models. In this review, organoid technology is discussed in the context of liver cancer models through comparisons to other cell culture systems. In addition, the role of the tumour extracellular environment in primary liver cancer will be highlighted with an emphasis on its importance in in vitro modelling. Converging novel organoid-based models with models incorporating the native tumour microenvironment could lead to experimental models that can better recapitulate liver tumours in vivo. Primary liver cancer (PLC) is the second leading cause of cancer mortality worldwide, with a steady increase in incidence over the last few years ,2. Each The highly malignant behaviour of PLC is not solely the consequence of cellular transformation. Recently, studies have shown the vital role of the tumour microenvironment in the initiation, progression, invasion and metastasis of cancer, particularly within the context of PLC ,14,15. TThe complex interplay between primary tumour cells, stromal cells, and extracellular environment is a limiting factor in the amount of treatment options currently available for PLC. Additionally, the anatomical and functional restrictions of the liver play a role in this as well ,17. PartOne pertinent cause of the lack of effective treatments in liver cancer is the limited number of reproducible, reliable models that are able to faithfully recapitulate the complex in vivo situation. Robust animal and human models for PLC can aid in understanding the molecular mechanisms behind the pathogenesis of PLC and provide pre-clinical platforms for the development of novel treatments. Mouse disease models and two-dimensional (2D) cell line cultures have historically been important pillars for preclinical development of cancer therapeutics. Although they have enabled deeper insights into cancer biology and tumorigenesis, their characteristics contain inherent limitations towards their overall applicability. Animal models and their relevance in PLC have been extensively reviewed elsewhere ,25,26,27Tumour-based in vitro models have been developed with a varying degree of complexity and a wide range of quantification methods, from reductionist 2D cell line models to full ‘mini-tumours’ including aspects of the tumour microenvironment ,30,31. CPLC cell lines have been well-characterized, are low-cost maintenance, and can be used for genetic modification, providing relatively robust and reproducible results . Due to Efforts have been made using cell lines to model patient-specific tumour characteristics, both in terms of phenotype and genotype ,41. HoweCulturing cells in a 3D environment leads to different morphological and physiological traits compared to conventional 2D culture ,43. ThisScaffold-based 3D cultures can be produced via cell seeding on a cellular 3D scaffold or by encapsulation into a liquid solution followed by solidification or polymerization of the liquid into a hydrogel. Both synthetic and natural materials are used in PLC research, either singular or as a combination, including polyvinyl alcohol (PVA)-gelatin , matrigeScaffold-free cultures do not require a base for cells to attach to and are mostly produced with bioreactors to direct single cells into spheroid-like structures, including forced floating, hanging drop, and agitation-based bioreactors ,60,61. SThus, 3D cultures using both patient-derived and mutation-induced PLC cell lines, whether scaffold-based or scaffold-free, still exhibit important limitations. These include lack of genetic diversity found in the original tumour after long-term expansion and unavailability of patient-matching healthy control cells.The term ‘organoid’ has been used for a variety of different culture conditions ,66, predThe establishment of organoid culture is fundamentally based on the notion that there are cells residing within each organ that possess stem cell characteristics and a self-organizing capacity. Various culture systems have been reported for these epithelial cells, but the missing ingredient was the lack of robust long-term culture possibilities. With the discovery of Lgr5 as a marker for these adult stem cells about a decade ago, a novel in vitro system was developed that was able to sustain long-term culture . The embAlthough organoids possess qualities that are similar to 3D spheroid culture of established cell lines, there are certain fundamental differences between the two culture methods. Firstly, a unique aspect of organoid culture is their ability to be established from patient-specific material and, thus, provide a solid platform for potential precision medicine approaches through direct chemotherapeutic testing or through molecular characterization . OrganoiHuman PLC organoids have been established in several studies ,76,77 FA. The prBuilding upon this, Li et al. expanded drug responses from PLC organoids by using a panel of 129 cancer drugs on HCC and CCA organoid lines, finding that there is a substantial intertumour as well as intratumour heterogeneity present , highligPik3ca and FGFR2-AHCYL1 fusion) in iCCA were induced, but showed to be only modest drivers for tumorigenesis in liver-derived organoids, suggesting that additional mutations and/or environmental or epigenetic factors are required.A different approach to study PLC with organoids is through driving healthy organoids towards cancer through engineered genetic mutations B. Via thAlthough organoids are widely regarded as a highly promising personalized in vitro model, several limitations are still present. As PLC contains substantial intertumour and intratumour heterogeneity, at present it is unknown how this cellular heterogeneity is recapitulated in the organoid cultures. Even though PLC organoids presumably are derived from rare cancer stem cell populations residing in tumours, to date it is unclear whether all cancer stem cell clones have similar organoid-initiation potential . OrganoiConcurrently, the predominant protocol of organoid culture requires animal-derived hydrogels, such as Matrigel or BME. Although well-suited for the culture of organoids, finding better matrices is pertinent due to the lack of controlled modifications and undefined growth factors present. Next generations of matrices for organoid culture are being explored, for example a synthetic polyethylene glycol (PEG)-based hydrogel was able to support murine liver organoid expansion to a certain extent . BuildinConverging these last two limitations of tumour organoids show a clear common denominator and underexplored topic: the extracellular environment of the tumour. Shifting the focus towards the extracellular environment allows for investigations into cell-ECM interactions, while at the same time exploring ways to find alternative culturing methods for cancer organoids. Hence, this review will delve more into the critical role the extracellular environment plays in PLC. We will discuss the possibility of converging organoid-based models with systems incorporating models of the tumour microenvironment. In turn, this can lead to a better understanding of the biology behind ECM composition and its influence on carcinogenesis.The classical view of cancer development through cancer cells accumulating consecutive genetic mutations in a multi-step process has been the predominant outlook for the last decades. Genomic-focused studies have found various important (driver) oncogenes and tumour suppressor genes but with relative modest success. This has led to a more comprehensive view that sees tumour progression as a dynamic crosstalk-driven element that encompasses the complete microenvironment of the tumour ,87. ThusHepatocellular carcinoma is a fairly unique carcinoma in that fibrosis and chronic inflammation, by hepatitis B and C commonly precedes the development of HCC , with upIn addition to composition, the physical properties of the TEE also influences PLC through providing biochemical and mechanical cues to PLC cells, with integrins regulating internal signalling pathways. Lysyl oxidase 2 (LOXL2) modifies the stiffness of the extracellular environment in HCC through cross-linking of fibrillary collagen I, which is involved in tumour growth and metastasis . SubsequA prominent desmoplastic extracellular environment is a hallmark of CCA, the bulk consisting of collagen type I and fibronectin . ParticuAnother effect of the desmoplastic TEE is through an increased rigidity resulting from remodelling proteins, particularly LOXL2 in CCA, crosslinking collagens and elastins . Cells rWith the vital role the extracellular environment plays in all facets of tumour biology, it is evident that creating an improved in vitro model of tumour performance requires a close mimicking of the composition, morphology and characteristics of the environment. Currently, research into elucidating interactions between the extracellular environment and cancer cells in PLC is relatively scarce. Particularly organoids as a platform for studying cellular interactions with the tumour extracellular environment in the context of PLC is non-existent, thus we look towards alternative culture models to highlight the importance of adapting organoid models to study these interactions. Broguiere et al.  used a sIn direct relation to PLC, but using cell lines, Schrader et al.  showed tThe ideal in vitro pre-clinical PLC model would eliminate species differences encountered in in vivo mouse models, and be able to accurately recapitulate the in vivo tumour of each individual patient, and allow for (direct) drug response testing. To this extent, the emergence of organoids in PLC has been highly promising as a physiologically relevant in vitro model. The fact that organoids can be established with high efficiency from patient-derived tissues, can represent the diverse spectrum of cancer subtypes, and can be used for both basic and translational research shows the high potential and versatility of this platform. In the future, it is vital to confirm the currently anecdotal validation, mainly in cystic fibrosis, of organoids as diagnostic tools and obtain robust specificity and sensitivity data on drug responses in organoids derived from individual patient’s tumours. Recent results with gastrointestinal organoids in a clinical setting have been hopeful . Well-deHowever, the ideal in vitro model should also include the incorporation of the tumour microenvironment. Efforts are underway by co-culturing cancer organoids with cellular components of the microenvironment, but the dependence on a basement membrane-like matrix is a hindrance for revealing the full potential of tumour organoids. Thus, incorporation of improved extracellular matrix mimicking substrates into a physiologically relevant in vitro system for experimental liver cancer models could increase our understanding of the biology behind tumour extracellular matrix composition and its influence on cancer. Converging novel organoid-based models with systems incorporating the native tumour microenvironment could lead to experimental models that can better recapitulate liver tumours in vivo.


The current insight into the neurobiological pathogenesis underlying social anxiety disorder (SAD) is still rather limited. We implemented a meta-analysis to explore the neuroanatomical basis of SAD. We undertook a systematic search of studies comparing gray matter volume (GMV) differences between SAD patients and healthy controls (HC) using a whole-brain voxel-based morphometry (VBM) approach. The anisotropic effect size version of seed-based d mapping (AES-SDM) meta-analysis was conducted to explore the GMV differences of SAD patients compared with HC. We included eleven studies with 470 SAD patients and 522 HC in the current meta-analysis. In the main meta-analysis, relative to HC, SAD patients showed larger GMVs in the left precuneus, right middle occipital gyrus (MOG) and supplementary motor area (SMA), as well as smaller GMV in the left putamen. In the subgroup analyses, compared with controls, adult patients (age ≥ 18 years) with SAD exhibited larger GMVs in the left precuneus, right superior frontal gyrus (SFG), angular gyrus, middle temporal gyrus (MTG), MOG and SMA, as well as a smaller GMV in the left thalamus; SAD patients without comorbid depressive disorder exhibited larger GMVs in the left superior parietal gyrus and precuneus, right inferior temporal gyrus, fusiform gyrus, MTG and superior temporal gyrus (STG), as well as a smaller GMV in the bilateral thalami; and currently drug-free patients with SAD exhibited a smaller GMV in the left thalamus compared with HC while no larger GMVs were found. For SAD patients with different clinical features, our study revealed directionally consistent larger cortical GMVs and smaller subcortical GMVs, including locationally consistent larger precuneus and thalamic deficits in the left brain. Age, comorbid depressive disorder and concomitant medication use of the patients might be potential confounders of SAD at the neuroanatomical level. Social Anxiety Disorder (SAD), formerly referred to as “social phobia,” is a commonly occurring and highly disabling psychiatric disorder, characterized by an extreme fear of being negatively evaluated in social or performance situations, thus leading to avoidance of social events or enduring them with excessive fear or anxiety . SAD usuA growing body of neuroimaging literature has investigated the brain structural mechanisms underlying SAD, despite heterogeneous disorder-related findings, with both increased and decreased volume, or cortical thickness, as well as null findings. The first voxel-based morphometry (VBM) study of SAD was reported in 1994 by Potts et al. , which fIn addition, the inconsistencies of these findings may further be confounded by clinical characteristics associated with brain morphometry, such as age, comorbid depressive disorder and concomitant medications, as well as methodological heterogeneity among studies , 20. ForThus, the current study performed a coordinate-based meta-analysis of magnetic resonance imaging (MRI) studies using the whole-brain VBM approach to investigate the regional GMV alterations associated with SAD. We also explored the effects of demographic and clinical variables as potential confounders, focusing in particular on the possible impact of age, comorbid depressive disorder and concomitant medication use on the regional GMVs in patients.We conducted a systematic search of the PubMed, Embase, and Web of Science databases for potentially eligible studies that compared GMV differences between SAD patients and healthy controls (HC) and were published in English up to February 2018. A combination of the following key words was used: “structural magnetic resonance imaging OR sMRI OR morphometry OR voxel-based OR voxel-wise OR voxel-based morphometry OR VBM” AND “social anxiety OR social anxiety disorder OR SAD OR social phobia (including public speaking phobia).” Broad search terms were used to minimize the likelihood of missing any relevant studies. We cross-referenced all relevant original research, reviews and meta-analyses, including the reference lists of eligible articles, to identify studies that were potentially missed in the literature searches.P-values, so that only differences between groups that met a threshold of p < 0.05 (corrected for multiple comparisons) or p < 0.001 (uncorrected for multiple comparisons) were deemed significant. For studies based on ROI analyses, we also requested the author(s) provide whole brain results if available. When the same patient group was used in multiple studies, only the study with the largest sample size was selected. If there were several subgroup comparisons, a combined summary result was preferentially included in the meta-analysis. For studies that used longitudinal treatment designs, only baseline pretreatment data were included.To be considered for inclusion, studies had to meet the following criteria: (1) compared GMV differences between patients with SAD and HC using structural MRI and were published as an original paper in a peer-reviewed journal, (2) included participants from all age groups , (3) used a whole-brain voxel-based morphometry (VBM) imaging approach, (4) reported stereotactic coordinates  space), (5) enrolled SAD patients–data from samples that included individuals with subclinical social anxiety and autism patients with social anxiety, were not included, and (6) reported A study was excluded if (1) SAD was investigated solely as a comorbid psychiatric condition or (2) the data were insufficient  even after the author(s) were contacted via email. Finally, we excluded any study that explicitly reported having used  data from another published study already included in our meta-analysis.The process of including literature was as follows. First, two independent reviewers (Xiuli Wang and Bochao Cheng) assessed the titles and abstracts of the search results and retrieved the relevant articles. Second, the full texts of all relevant articles were assessed based on the inclusion and exclusion criteria to determine the included articles. Then, for each study included in the meta-analysis, peak coordinates data of GMV differences found significant at the whole-brain level  were independently extracted by two authors (Xiuli Wang and Bochao Cheng) to minimize data extraction errors according to the AES-SDM method . InconsiA quantitative coordinate-based meta-analysis approach, i.e., the anisotropic effect size version of seed-based d mapping (AES-SDM), allows the results of individual studies to be weighted and controlled for several moderator variables, including demographic, clinical and imaging factors . This mehttp://www.sdmproject.com/), version 5.141  of GMV differences were used to recreate, for each study, a map of the effect size of the GMV differences between individuals with SAD and HC. Second, a standard MNI map of the differences in GMV was separately recreated for each study by means of an anisotropic Gaussian kernel with a 20 mm half-width, which assigns higher effect sizes to the voxels more correlated with peaks. Third, the mean map was obtained by voxel-wise calculation of the random-effects mean of the study maps, weighted by sample size, within-study variance and between-study heterogeneity. Division of meta-analytic effect sizes by their standard errors yields z-values, but these were not normally distributed; thus, statistical significance was assessed using a permutation test. For all main analyses, it has been shown that p < 0.005 (uncorrected) with a cluster-level extent threshold of k > 10 optimally balances false positives and negatives  and only included findings in regions detected in the main analysis  author names, (b) date of publication, (c) subject group numbers, (d) mean age with standard deviation, (e) gender ratio, (f)comorbid depressive disorder, (g) currently concomitant medication, and (h) the coordinates associated with larger or smaller GMVs in the SAD patients compared with the HC.http://www.nitrc.org/projects/mricron/), which provided templates to visualize the results with MNI coordinates.Peak coordinates were submitted to MRIcron . The male percentages of SAD patients  and healthy subjects  were not significantly different .As shown in Figure The exploratory whole-brain VBM analysis revealed significant GMV alterations in SAD patients compared with HC. The SDM value and number of voxels in the case vs. control comparison performed in this meta-analysis are reported in Table In the main meta-analysis, relative to HC, SAD patients had larger GMVs in the left precuneus, right supplementary motor area (SMA) and middle occipital gyrus (MOG), as well as a smaller GMV in the left putamen (see Table In eight studies recruiting adult SAD subjects (age > 18 years) with 384 patients and 445 HC, the subgroup analysis revealed that, relative to controls, adult patients with SAD had larger GMVs in the left precuneus, right superior frontal gyrus (SFG), SMA and angular gyrus  and the MOG), as well as a smaller GMV in the left thalamus Table . ClusterIn five studies recruiting SAD patients without comorbid depressive disorder, including 109 patients and 135 HC, the subgroup analysis revealed that, compared with controls, SAD patients without comorbid depressive disorder had larger GMVs in the left superior parietal gyrus (extending to the precuneus), right inferior temporal gyrus (extending to the fusiform gyrus) and right MTG [extending to the superior temporal gyrus (STG)], as well as smaller GMVs in the bilateral thalami Table . ClusterIn seven studies recruiting SAD patients without current medication use, including 190 patients and 201 HC, the subgroup analysis revealed that, compared with controls, drug-free SAD patients had a smaller GMV in the left thalamus, while no larger GMVs were found Table . Clusterp < 0.0005 to minimize spurious findings, the meta-regression analyses revealed that the alterations of the brain GMV in SAD patients in the main analysis including all studies were not significantly associated with the mean age, percentages of male patients, right-handed patients [available in all studies but one   and a thalamic deficit in the SAD patients with different clinical characteristics compared with the HC. A functional imaging study also found that disorder-related scenes, compared with neutral scenes, evoked differential responses in SAD patients in a widespread emotion processing network including limbic structures  and cortical regions , which emphasized a central role for the precuneus in disorder-related scene processing . StructuSimilarly, patients with GAD showed a significantly reduced GMV in the left thalamus compared with HC . SAD patTaken together, the above findings point to a possible anatomical substrate of SAD expressed by GMV abnormalities. The GMV abnormalities might underlie or derive from either a functional disturbance of the cortical regions or a disrupted regulation between the cortical regulating regions and the subcortical targets of regulation in SAD patients. Future studies in SAD populations may target these regions as an a priori focus of investigation to confirm which trait-like GM alterations are typically associated with SAD.When considering the subjects' age, the current research revealed GMV alterations in adult patients with SAD relative to HC, i.e., larger GMVs in the right dorsolateral prefrontal cortex (DLPFC), SMA, angular gyrus, and middle temporal and occipital gyrus as well as a deficit in the left putamen. Our study found similar results in adult patients (age ≥ 18 years) relative to those in the total patients, and no significant age correlation. Thus, it might be suggested that, to a certain extent, the age of the patient group has little effect on the brain GMVs of SAD patients in the current study. Consistent with our findings, some studies have found increased cortical thickness of the right DLPFC, the parietal cortex including the angular gyrus, and the left temporal cortex in adult SAD patients compared with controls , 72. SimIt was reported that SAD patients showed activations in the right DLPFC, MTG  and leftWith regard to subcortical structures, and in line with our finding, Potts et al. found an age-related reduction in the putamen volume in SAD patients . The putWith comorbid depressive disorder as a potential confounding factor, our study revealed that SAD patients without comorbid depressive disorder had larger GMVs in the right superior, middle and inferior temporal gyrus, fusiform gyrus and left superior parietal gyrus including the precuneus, as well as smaller GMVs in the bilateral thalami compared with controls. In line with our finding, one study identified increased cortical thickness in the right parietal cortex in the whole-brain analysis and, temporal region in the ROI analysis in SAD patients without comorbidities compared with HC . SimilarWhen considering concomitant medication use, our finding of only the left thalamic GMV deficit in currently unmedicated SAD patients compared with controls is directionally consistent with one pilot study that found cortical thinning in currently untreated SAD patients . HoweverTaken together, these findings suggest that the age, comorbid depressive disorder and concomitant medication use of SAD patients may affect the anatomical features of SAD. In view of the preliminary findings of our research and their possible relationship with functional alterations in brain reactivity , it needIt was also of note was that our study found no social anxiety-related amygdaloid and hippocampal volumetric variation (null findings), in line with two studies , 22, whiOur study has several limitations, some of which are inherent to the meta-analytic procedure, such as the heterogeneity of the SAD samples between the different studies. First, publication bias is nearly unavoidable despite the efforts we have made to embrace as many unpublished VBM studies and null-findings as possible. The fact that we were not able to fully review all the GMV evidence for SAD was a potential limitation of the present work. Second, our research was limited by the inclusion of relatively small studies on the structural abnormalities of SAD, resulting in limited statistical power. Third, the included studies covered subjects with a wide age range, although the current study performed the subgroup analysis between adult SAD patients and controls and the meta-regression analysis of the age of the patient group. Fourth, we could not determine whether these structural alterations were part of the pathogenesis or a consequence of the disorder because of the cross-sectional nature of the included studies. Moreover, we did not specify the SAD subtypes  of the patients or how many of them had indicators of other anxiety disorders such as GAD and panic disorder, which might act as potentially confounding factors. Finally, it should also be noted that only current medication status had been taken into consideration. We were not able to directly analyse medication effects in a more fine-grained fashion due to insufficient data.In conclusion, our findings provided evidence for the involvement of cortical-subcortical GMV alterations in the pathophysiology of SAD. Overall this study revealed directionally consistent larger cortical GMVs and subcortical GMV deficits in SAD patients relative to HC, including locationally consistent larger precuneus and thalamic deficits in the left brain. Age, comorbid depressive disorder and concomitant medication use might be among the potential confounders at the neuroanatomical level of SAD patients. Our findings of the altered neuroanatomical structures may help explain the dysfunctional processing and regulation of emotion in SAD. Prospective and longitudinal studies including homogeneous SAD patients, coupled with uniform multimodal neuroimaging techniques, are needed to elucidate the neuropathological mechanisms underlying SAD and to further clarify the trajectories of neurobiological alterations and their associations with clinical features and specific medication exposure over time.XW and SW contributed to the conception of the study. XW, BC, and SW contributed significantly to the analysis and manuscript preparation; XW, BC, LQ, and QL performed the data analyses and wrote 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.


Studies were included if the program (1) included a control group, (2) included at least 3 interventions, (3) were at least 6 months in duration, and (4) included measurement of cognitive performance as an outcome. Results: In total, 17 multidomain lifestyle programs aimed at enhancing cognitive reserve and reducing risk of ADRD were found. Thirteen programs are FTF in intervention delivery, with 3 FTF programs replicating the FINGER protocol as part of the World Wide Fingers Consortium. Four programs are delivered digitally . Program characteristics  and results of completed and prospective studies are reviewed and discussed. Conclusion: This review updates and discusses completed and current multidomain lifestyle interventions aimed at enhancing cognitive reserve and reducing risk of ADRD. A growing number of international studies are investigating the efficacy and utility of these programs in both FTF and digital contexts. While a diversity of study designs and interventions exist, FTF and digital programs that build upon the foundational work of the FINGER protocol have significant potential to enhance cognitive reserve and reduce risk of ADRD.Background: Currently, there is no pharmaceutical intervention to treat or delay pathological cognitive decline or Alzheimer’s disease and related dementias (ADRD). Multidomain lifestyle interventions are increasingly being studied as a non-pharmacological solution to enhance cognitive reserve, maintain cognition, and reduce the risk of or delay ADRD. Review of completed and prospective face-to-face (FTF) and digital multidomain interventions provides an opportunity to compare studies and informs future interventions and study design. Methods: Electronic databases (PubMed, PsycINFO,  An estimated 50 million individuals are currently living with Alzheimer’s disease and related dementias (ADRD) globally , with a Currently, no pharmacological disease modifying therapies (DMT) exist for the prevention or treatment of ADRD . The pasNon-pharmacological trials aimed at ADRD risk factor reduction emerged in the early 2000s. These clinical trials focused on single domain interventions such as physical exercise , cardiovThis study provides a comprehensive overview of completed and prospective non-pharmacological multidomain lifestyle interventions that aim to enhance cognitive reserve and reduce risk of ADRD. The review summarizes participant and intervention characteristics, study length and intervention frequency, primary and non-primary outcomes, adherence, and attrition. It also synthesizes studies completed to date and discusses how current and prospective studies are incorporating data reported from completed studies to further refine and optimize FTF and digital multidomain interventions.A literature search utilizing PubMed, PsycInfo, ClinicalTrials, and NIH RePORTER was conducted from inception to August 1, 2019. Following previously utilized criteria, to be considered in the current review the study or protocol was required to meet a set of inclusion criteria associated with qualification as a multidomain lifestyle intervention to enhance cognition and reduce risk of ADRD . The FINThe preDIVA study (ISRCTN29711771) was a Dutch cluster-randomized control trial that evaluated the effect of a nurse-led multidomain intervention on cardiovascular risk factors and its effect on dementia incidence and disability in a sample of community-dwelling older adults aged 70–78 years ,27. Recrz-score) of multiple cognitive tests  orientation items, Digit Symbol Substitution Tests, and Category Naming test). Individual components of this primary measure made up secondary measures, along with the Short Physical Performance Battery, Activities of Daily Living Prevention Instrument, Clinical Dementia Rating, frailty, and geriatric depression scale (GDS) scores. Of the 1268 (77%) participants that completed the study protocol, the multidomain-plus supplement group showed a slight increase in the primary composite score compared to a decrease in score from the placebo group, although these differences were found to not be significant. Three-year differences between baseline scores for multi-domain plus placebo and placebo group and baseline score for the supplement group and placebo group were also shown to be non-significant. Between group comparisons of secondary outcomes showed a slight difference for primary outcome components (only significant between multidomain + supplement vs. placebo). Nevertheless, the effects of the multidomain behavioral interventions (with or without omega 3 supplementation) on cognition—While not statistically significant—demonstrated trends toward early and sustained effects [Utilizing a randomized four-arm placebo control design, the MAPT study investigated the efficacy of a dietary supplement and a multidomain intervention strategy (both in isolation and combination) versus placebo control for the prevention of cognitive decline ,28. Part effects .The FINGER study was one of the earlier multidomain intervention studies carried out to investigate the prevention of cognitive decline and related disability in a population of at-risk older adult participants from across Finland . This stThe SPRINT-MIND study was a sub-study of the SPRINT study to examine how intensive blood pressure interventions affect the incidence of MCI and dementia . This RCn = 1152), participants will be separated into a group with advanced care (intervention) and a group with basic care and general health advice (control). The intervention program includes diet, exercise, cognitive training through tablet computers, and social engagement programs. It also offers participants assessments for depressive symptoms/risk factors, ways to assess and reduce vascular risk factors, and optimized medication plans if needed. Fully structured interviews will occur at baseline and 24-months for both groups, with the intervention group receiving an additional visit at 12 months to improve motivation and adherence to the program. The participants will also receive 5 phone calls throughout the course of the intervention to support adherence. This will look for differences in outcomes between the control and intervention group, using change in cognitive performance measured using a composite of z-scores from multiple neuropsychological batteries. The investigators will also track secondary endpoints such as mortality, depressive symptoms, and daily living, as well as readiness for behavior change in participants.The Age Well.de study plans to further the research of multidomain interventions for cognitive impairment by offering a multi-center study with older-adult German participants. This ongoing study is investigating the feasibility of multi-domain interventions involving diet, physical activity, cognitive training, and vascular risk factors, and also includes recommendations for social lifestyle and medicine underuse/overuse . SpecifiThe SMARRT study plans to consolidate practices used commonly within multidomain intervention studies and compare outcome data to participants receiving generalized health education among older adults in the U.S. . The SMAThe MIND-ADmini study (NCT03249688) plans to use established multidomain intervention strategies to assess the efficacy of these interventions in a sample of 150 older adults aged 60–85 diagnosed with prodromal Alzheimer’s disease as defined by 1 standard deviation below age-based norms on 2 measures of cognitive function, including at least 1 measure of memory. The study is currently being conducted at sites in Sweden, Finland, Germany, and France using participants aged 60-85 years with preexisting cognitive impairment (excluding dementia). Adopting many practices used in the FINGER protocol, the MIND-ADmini will use three intervention arms. One will receive regular health advice (Control), one will receive FINGER-style interventions (Multidomain 1), and one will receive FINGER-style interventions with a multi-nutrient product to supplement diet (Multidomain 2). The primary outcome of this trial is the feasibility of the intervention, but adherence to intervention and lifestyle changes will be assessed as well. Cognition, independent living, and dementia scores will also be gathered to develop estimates for a larger future study (MIND-ADmaxi). This study will primarily focus on determining how successful adherence and intervention retention is. The MIND-ADmini will also build on past works with prodromal AD participants using the “medical food” supplement by seeing how its use may complement FINGER-style interventions. A 6-month extension to this study will also be considered once the original time frame has been completed.The EMuNI study (NCT03382353) will break down popular components from a number of lifestyle intervention studies to look at specific effects of intervention strategies on cognitive performance endpoints and MRI markers for progression of Alzheimer’s Disease. Interventions on diet and lifestyle have shown to help with the onset of cognitive decline, and the EMuNI study plans to administer these interventions with increasing intensity. Control  participants will learn about cognitive domains through educational lessons and videos, partial treatment (PT) participants will consume a dietary supplement and receive nutritionist led lessons on a brain-healthy diet, and full treatment participants (FT) will receive the PT interventions along with supervised exercise and cognitive training sessions. This study is recruiting Italian adults aged 60–80 years with existing memory complaints and aims to determine if the combination of lifestyle interventions over the course of one year will lead to improvement in cognitive performance and positive magnetic resonance imaging (MRI) markers . Additionally, the investigators hypothesize that the combination of interventions will increase positive outcomes such that PT participants show more positive results than NT, and FT participants showing the most positive outcomes. Cognitive decline often progresses to clinical levels before the proper steps to prevent or delay further decline can be taken. While many multicomponent studies investigate interventions in at-risk populations, this design plans to test the efficacy of these interventions in clinical populations. Using an equal number of participants with SCD and MCI, this study (NCT04023032) will collect 16 weeks of historical control data before the participants receive a multidomain cognitive intervention. The intervention includes cognitive training and cognitive rehabilitation, which aim to restore cognitive functions and providing strategies to support activities of daily life. Lifestyle and psychological interventions are also included, ranging from providing information on ways to balance risk factors  and targeting common neuropsychiatric symptoms in SCD and MCI. These interventions will be carried out in weekly group sessions and 2 individual sessions over the course of 4-months, totaling 16 90-minute sessions. Participant status will be assessed using change in measures of memory capabilities and activities of daily living, as well as scores on individual cognitive batteries and anxiety/depression assessments.Another planned extension of the Brain, Body, Life studies, this trial will examine the effects of a lifestyle intervention plan on reducing dementia risk, specifically when a more thorough intervention is compared alongside a more standard approach . This stThe promising results reported on from the FINGER study has resulted in an initiative to explore the applicability of similar interventions across unique countries and cultures. Founded by Dr. Miia Kivipelto, the principal investigator of the FINGER trial, the World Wide FINGERS hopes to create an international network in which the key aspects of the FINGER trial can be replicated in countries around the world . This glThe U.S.-based outreach of the WW-FINGER initiative, the POINTER study (NCT03688126) will take the practices of the FINGER trial and test whether a similar intervention, tailored to U.S. culture, can help protect against cognitive decline in at-risk adults. This program will utilize a Structured Lifestyle Intervention which involves a program addressing diet, physical and cognitive exercise, and managing cardiovascular risks. Control participants will be given a self-guided intervention in which education, support, and tools to manage lifestyle practices are provided to participants. While many major disease cases will exclude participants from this study, the study is primarily seeking participants with poor diet, low levels of physical activity, and a direct family history of significant memory impairment. This is to purposefully include a sample that would uniquely benefit from lifestyle interventions. Participants will be recruited near testing sites in North Carolina and California. This study will explore the usefulness of this intervention strategy in a U.S. sample, as well as changes in global cognition and general health targeted by the intervention program.The MIND-CHINA study aims to determine the effect of a multidomain lifestyle intervention adapted for Chinese culture on cognitive outcomes. This project, developed in collaboration with developers of the FINGER protocol, will utilize a similar multidomain intervention to the FINGER protocol in a sample of older, rural community-dwelling Chinese adults. Participants will be randomized into a cardiovascular risk factor management program (active control) or a cardiovascular risk factor program with additional multidomain lifestyle interventions. This intervention will be developed keeping cultural and lifestyle differences in mind, utilizing multi-disciplinary researchers from the Shandong Provincial Hospital to provide a proper intervention for rural Chinese adults.The SINGER initiative is a trial that will test the efficacy and ease of implementation of a FINGER-like intervention for older adults in Singapore. As 20% of the population in Singapore is age 65 or older, this study will help elucidate if this type of intervention could benefit older Singaporean adults. Currently, a 6-month feasibility study is being conducted with a sample of 150 Singaporean older adults with MCI. This project is currently underway, and study investigators are working closely with investigators from the FINGER trial to develop a culturally sensitive intervention to help prevent future cognitive decline.Additionally, two more country or region-specific deployments of FINGER are under way. The Australian-Multidomain Approach to Reduce Dementia Risk by Protecting Brain Health with Lifestyle intervention (AU-ARROW) is a 2-year intervention trial replicating the US POINTER study with an additional 6-month follow-up timepoint to assess sustainability of potential benefits. The GOIZ-ZAINU study is a pilot, controlled, randomized, one-year multimodal interventional study launched in June 2018. This study is adapting the FINGER protocol for the social and cultural context of the Basque population. Two hundred adults aged 60 or older will be enrolled with a CAIDE Dementia Risk Index score of 6 points or higher and below-expected performance on one brief cognitive screening task. Exploratory analyses will investigate reduction in risk scores and objective cognitive , Table .z-scores included in the “MYB Battery”. Secondary outcomes span a number of domains, including dementia incidence/cognitive impairment, intervention impact, and impact on module-targeted risk factors.The Maintain Your Brain (MYB) study aims to reduce cognitive decline in a population of older Australian adults using a multimodal lifestyle intervention strategy administered exclusively through an online platform . This stWhile existing FTF interventions have demonstrated meaningful participant engagement, these studies remain geographically constrained and require a significant amount of labor . A numbeBuilding on a series of works, the BBL-CD trial is the most recent iteration of a multidomain dementia risk factor intervention program that has been adapted for participants with cognitive impairment ,59,60. TThe HATICE trial was developed to address a number of modifiable lifestyle-related and vascular risk factors found in cases of dementia and cardiovascular disease (CVD) in older adults ,62. The Alzheimer’s disease and related disorders (ADRD) pose population health risks to virtually every society around the world. The health, societal, and economic burdens associated with ADRD have transformed ADRD into a global health priority ,4,63,64.The existing evidence base from completed multidomain RCTs points to the clinical utility of non-pharmacological, lifestyle-based interventions for enhancing cognitive reserve and reducing risk of ADRD. At the same time, these studies point to the necessity of multidomain interventions to successfully address the multiple risk factors associated with ADRD in aging populations. One of the enduring challenges in the development of pharmacological DMTs for ADRD has been intervening at the point in disease progression that is clinically efficacious . To dateThe unique use cases for non-pharmacological multidomain interventions also warrant consideration. Within clinical research contexts, the use of clinical diagnostic criteria such as the recently adopted NIA-AA criteria for asymptomatic or pre-clinical Alzheimer’s disease  provide As multidomain intervention studies are now being implemented across the globe, effective localization of these interventions will grow in importance. To date, the evidence base for these studies has occurred in high-income countries, with substantial infrastructure and clinical workforce for the deployment of these programs. Yes, it is clear that middle- and lower-income countries will be adversely affected by ADRD in the coming decades ,87,88. TA unique opportunity exists for digitally-mediated multidomain intervention programs to reach populations in low- and middle-income countries in ways that physical infrastructure and clinical work forces cannot ,90. DigiA common challenge to both FTF and digital multidomain intervention programs is adherence. The FINGER study reported high engagement (7% dropout at 12-months) with variable adherence across individual intervention components . Similarly, adherence in the MAPT study was variable  . AdherenThe public health relevance of these non-pharmacological approaches is an important consideration. A shift in mindset from pharmacological cure to lifestyle care is needed in order to embrace the significant potential benefits of enhancing cognitive reserve and reducing risk of ADRD. Even small reductions in ADRD incidence will have outsized public health impacts. Given that as much as many as half of all cases of ADRD may be attributable to modifiable risk factors , non-phaIn the near future, the measurement and management of cognitive health from mid-life onwards will provide for proactive intervention to enhance cognitive reserve, reduce risk factors associated with pathological cognitive decline including ADRD, and optimize cognitive aging at the societal and population levels. For this to be achieved, a combination of FTF, brick and mortar multidomain lifestyle interventions, and digitally delivered multidomain interventions are needed. Digital interventions and digital therapeutics such as those reviewed here are critical adjuncts to FTF interventions that support engagement and adherence, while simultaneously serving as an effective stand-along delivery mechanism for evidence-based enhancement of cognitive reserve and risk reduction. In a similar way to how cardiovascular disease and diabetes mellitus are currently addressed at a population health level—With non-pharmacological lifestyle interventions as the first line intervention for both prevention and treatment—Multidomain lifestyle interventions are poised to be the first line intervention for prevention and treatment. Additionally, as effective repurposed or novel pharmacological DMTs emerge, drug-based interventions can be used in combination with lifestyle interventions to complement or increase efficacy utilizing a precision medicine approach. A dual therapy approach, including both pharmacological and non-pharmacological interventions, may represent the most optimistic future for the prevention and treatment of ADRD. However, while this optimistic future is not a reality, the reality of FTF and digital multidomain lifestyle interventions to enhance cognitive reserve and reduce risk of pathological cognitive decline provides much needed optimism and offers the potential to slow the growing number of individuals living with ADRD.


Mesenchymal stromal cells (MSCs) have attracted intense interest due to their powerful intrinsic properties of self-regeneration, immunomodulation and multi-potency, as well as being readily available and easy to isolate and culture. Notwithstanding, MSC based therapy suffers reduced efficacy due to several challenges which include unfavorable microenvironmental factors in vitro and in vivo.In the quest to circumvent these challenges, several modification techniques have been applied to the naïve MSC to improve its inherent therapeutic properties. These modification approaches can be broadly divided into two groups to include genetic modification and preconditioning modification . This field has witnessed great progress and continues to gather interest and novelty. We review these innovative approaches in not only maintaining, but also enhancing the inherent biological activities and therapeutics of MSCs with respect to migration, homing to target site, adhesion, survival and reduced premature senescence. We discuss the application of the improved modified MSC in some selected human diseases. Possible ways of yet better enhancing the therapeutic outcome and overcoming challenges of MSC modification in the future are also elaborated.The importance of prosurvival and promigratory abilities of MSCs in their therapeutic applications can never be overemphasized. These abilities are maintained and even further enhanced via MSC modifications against the inhospitable microenvironment during culture and transplantation. This is a turning point in MSC-based therapy with promising preclinical studies and higher future prospect. The introduction of cell therapy has made dramatic contribution to science and continue to expand in value and utility in regenerative medicine and disease therapeutics. Experimental and clinical applications of cell therapy has covered many diseases including cardiovascular conditions –3, ParkiGenerally, MSCs are plastic adherent population of cells, having self-renewing ability and capable of differentiating into adipogenic, osteogenic and chondrogenic lineages, among others. They possess intense immunomodulatory property but low immunogenicity. All MSCs isolated from various sources have common characteristic functions of inducing regeneration as well as maintaining general tissue homeostasis due to their special inherent properties including the ability to home at target sites . To dateRegardless of the immense contributions and successes associated with MSC-based therapy, there has always been the need for improvement to enhance the inherent properties and circumvent the confronted challenges. This quest has made room for the modification of MSCs, resulting in an improved and highly specific therapeutic effects in many experimental studies while clinical trials are still in their early stages with preliminary aims to evaluate safety, efficacy and feasibility –24. The In the genetic modification of MSCs, a constructed gene cassette is loaded into a vector for easy entry into the MSC. Once inside the MSC, it produces or overexpresses certain specific genes. The transgene expression could either remain constant resulting in characteristic synthesis of specific molecular proteins or could be regulated via a gene switch .Genetic modification of MSCs seeks to improve cellular survival, increase migration, homing and adhesion to target sites, as well as avert poor MSC division and growth (senescence). On the basis of enhancing MSC migration, the induction of CXC chemokine receptors 1, 4 and 7 overexpression has been employed . While COptimum adhesion of MSCs is crucial in the determination of their proliferation and viability on surfaces of substrates and contribute to cellular engraftment and tissue regeneration. This adhesion is known to be linked with integrins, which control cell-extracellular matrix (ECM) and cell–cell adhesion mechanisms through adhesion molecules and ECM binding . In thisMSCs are also modified to increase their survival time against the unfavorable microenvironment within which they are administered or cultured. This makes room for the cells to thrive longer enough to illicit sufficient therapeutic effects. Integrin-linked kinase (ILK) overexpression in MSCs increased their survival and angiogenesis via AKT and mTOR signaling pathways in an infarcted myocardium. It was noticed that the ILK-overexpressed MSCs increased MSCs survival at day 4, and angiogenesis at week 3 post transplantation . A similHepatocyte growth factor (HGF) is another significant cytokine that participate in angiogenesis, anti-inflammation and anti-apoptosis. MSCs overexpressing HGF are reported to have high therapeutic influence in cardiovascular diseases , liver il-lysine (PLL) was found to effectively prevent senescence and augment growth of MSCs [Another critical focus of genetic modification of MSCs is to prevent premature senescence of cultured or transplanted cells. Cellular senescence, which essentially refers to the irreversible cellular proliferation arrest, greatly contributes to reduced MSC functions. Genetic modification of MSCs involving Sox2 and Oct4 genes overexpression, have been shown to efficiently improve differentiation and proliferation potential of transplanted MSCs , as well of MSCs . This wa of MSCs . On this of MSCs .Again, telomerase reverse transcriptase (TERT) transfected MSCs were reported to hinder senescence and possess higher proliferative and cell cycle-related gene expression factors , and as Preconditioning of MSCs encompasses the ex vivo treatment with both chemical and physical factors via specifically designed environment. Just as discussed above, preconditioning is also meant to maintain and enhance the intrinsic therapeutic properties of MSCs Fig.  against MSCs generally thrive in a low oxygen tension environment usually between 1–5%  or 1–7% On the background of their previous report that, IL-3 prevents bone and cartilage damage, and increases the differentiation potential of MSCs into functional osteoblasts, Barhanpurkar-Naik et al.  further 2 concentration. These factors alongside the evoked expression of HIF-1α and phosphorylation of Akt, cause higher MSCs adhesion, migration and survival [Just as elaborated earlier, hypoxic preconditioning of MSCs boosts their capacity to engraft and survive in target tissues. Liu and colleagues demonstrate that, MSCs express high levels of both SDF-1 receptors, CXCR4 and CXCR7 under 3% Osurvival . Bone masurvival . Plasminsurvival .2) preconditioning is greatly upregulated via the HIF-1α-GRP78-Akt signal axis, leading to enhanced survival, proliferation, migration and angiogenic cytokine secretion potential of transplanted MSCs. Preconditioning is known to even restore impaired functions of MSCs as demonstrated by Khan and colleagues in a diabetic affected MSCs using the growth factors IGF-1 and FGF-2 [Under oxidative stress, MSCs are highly prone to apoptosis accompanied by reduced functional activity. In investigating factors that avert this effect, MSCs preconditioned with tumor necrosis factor-α (TNF-α) were found to not only promote MSCs survival, but also migration and proliferation to repair endothelium in intimal hyperplasia of vein grafts . The signd FGF-2 . A similnd FGF-2 .On the basis of enhancing communication with the immune system to protect MSCs, treatment with interferon gamma (IFN-γ) produces increased suppression of NK cells activation, hence protecting MSCs from NK cells-mediated cytotoxicity , and the2 enhances proliferation, viability, stemness and chemokine related genes expression including CXCR7 and OCT4. It again prevents phenotypic changes in MSCs such as cellular morphology and the expression of senescence-associated-β-gal [2 enhances bioactivity, proliferation and survival via the suppression of the cell death signaling pathway and augmentation of angiogenic cytokine secretion [2 exhibits higher chondrogenic differentiation ability by preventing cellular senescence and promoting the proliferative capacity of human synovial MSCs [Hypoxic preconditioned-MSCs exert superior protected role and has been confirmed to involve HIF1α and Beclin1 signaling pathway in several conditions –98. Preted-β-gal . Furtherecretion , while 5ial MSCs .Withania somnifera root and Tinospora cordifolia leaf extracts were employed to modify Wharton’s jelly MSCs. Analysis shows delayed senescence, decreased apoptotic cells, increased proliferation and increased G2/M phase of the cell cycle [Herbal extracts have also been used to precondition MSCs to examine their effects on senescence and proliferation properties of MSCs. In one of such studies, ll cycle . The effll cycle . Other mll cycle , IL-1β, ll cycle . Apelin,ll cycle .With focus on circumventing in vitro and in vivo factors that cause the ordinary MSC to lose its intrinsic properties of proliferation, differentiation and survival, MSCs have been modified and applied in several diseases. The cycle of naïve MSCs to modified MSCs towards clinical application is illustrated in Fig. MSCs are known to enhance neurogenesis and effect neuroprotection. During MSC transplantation in brain injury, it is expected that sufficient cells move into the injured site to exert enough therapeutic effect. This has made local application a common practice. However, direct local inoculations are confronted with brain tissue damage and induced inflammation , whereasThe therapeutic utility of MSCs in cardiac conditions is based on the MSCs capability of directly differentiating into cardiac tissue, and as well release paracrine factors to promote infarct repair, regenerate damages, improve vascular supply and restore myocardium function. The use of MSC or cell therapy in general has been a promising approach in this direction. However, the overall restorative ability of these cells appear confined basically due to low engraftment, in addition to poor cell viability within the ischemic myocardium microenvironment. Huang and colleagues earlier hypothesized that, inadequate chemokine receptors on MSCs could be a factor for the deficiency in survival and engraftment . In theiDamage to any compartment of the lung due to chemical, physical, or biological factors/agents which ultimately leads to inflammatory reactions, constitute lungs injury. The induced injury affects cellular components such as DNA, proteins and lipids leading to cell death. Unfortunately, available medical management largely remain supportive, hence the need for countermeasures of which MSC therapy is promising. Among the several MSC therapy studies conducted in this field include a radiation induced lungs injury experiment, where Liu and colleagues noticed that, although the ordinary MSC decreases apoptosis and infiltration of lymphocyte, and as well increases epithelial cells proliferation and fibrosis inhibition in the later phase, the decorin-modified MSC produces a more enhanced therapeutic effect . SimilarDiabetes and its associated obesity are swelling in numbers at an alarming rate worldwide, resulting in increased co-morbidities. Although optimal management remains elusive, MSC therapy in this field has attracted a lot of attention with highly encouraging results. In obese diabetic mice model, intra-peritoneal administration of MSCs modified to overexpress enhanced green fluorescent protein (eGFP) and superoxide dismutase (SOD2), effectively home in inflamed fatty pockets, consequently improving glucose tolerance and reducing total body weight at week 4 . SimilarUnder normal circumstances, ordinary MSCs may lose their intrinsic functions due to long period of in vitro cultivation, poor isolation procedure, and harsh environmental, and death signals upon in vivo inoculation. Modification of these cells genetically or by preconditioning does not only cause the retention of their characteristic properties, but also enhance their overall efficacy in therapeutics. One major short coming of MSC transplantation is their inability to sufficiently migrate and get engrafted or concentrate at the injured site, sometimes due to entrapment within lung and lymphoid organs. This has contributed to local inoculation currently being the most preferred method of administration . HoweverPractically, MSC therapy occurs in a damaged cellular setting, where the microenvironment is harsh and embodies several destructive factors. With focus on the need to ensure that transplanted cells capably cope within such an environment by surviving enough to impact sufficient therapeutic influence, MSCs have been modified . A lot oThe unmodified MSCs as a therapeutic tool is again confronted with the challenge of lack of standardization leading to therapeutic discrepancies. A review paper by Galipeau, elaborated the lack of standardized MSC products throughout academic centers and industries to include donor variance, senescence and epigenetic reprogramming followed by culture expansions, induced immunogenicity during culture and cryopreservation . NotwithIrrespective of the successes of modified MSCs therapy, excessive loss of transplanted cells still remain an unresolved challenge. This is the result of both in vitro and in vivo detrimental environmental factors or lack of favorable factors, inducing premature senescence and loss of survival signals. This calls for mounting strategies that targets specific molecular mechanisms or pathways and by inducing a broader scope of cytoprotection. Again, combined modification techniques and molecules/factors that enhance MSC survival, migration, homing, and adhesion could further optimize cell survival and maximize therapeutic effects. Finally, specific secretomes expressed by modified MSCs are largely responsible for the transplanted effects. Further identification, characterization and subsequent application of such therapeutic factors could yield more effective clinical outcomes.The importance of prosurvival and promigratory abilities of MSCs in their therapeutic applications can never be overemphasized. Again, their capability to adequately home at injury site and effectively differentiate, proliferate and enact their paracrine and endocrine influences, are the desired outcome of MSC based therapy. These effects are maintained and even further improved via MSC modifications. By and large, MSC modifications have produced better therapeutic impact with high specificity to targets than the ordinary cell. However, more studies on the combination of different genetic modification and/or preconditioning techniques or factors, leading to a combined application of these modified MSCs would ensure better outcome and novel discoveries, and further enhanced therapeutic goals. Again, there is the need to mount more focal investigations to identifying and understanding the many factors that influence MSC modification.


Magnetic Resonance-guided radiotherapy (MRgRT) marks the beginning of a new era. MR is a versatile and suitable imaging modality for radiotherapy, as it enables direct visualization of the tumor and the surrounding organs at risk. Moreover, MRgRT provides real-time imaging to characterize and eventually track anatomical motion. Nevertheless, the successful translation of new technologies into clinical practice remains challenging. To date, the initial availability of next-generation hybrid MR-linac (MRL) systems is still limited and therefore, the focus of the present preview was on the initial applicability in current clinical practice and on future perspectives of this new technology for different treatment sites.MRgRT can be considered a groundbreaking new technology that is capable of creating new perspectives towards an individualized, patient-oriented planning and treatment approach, especially due to the ability to use daily online adaptation strategies. Furthermore, MRL systems overcome the limitations of conventional image-guided radiotherapy, especially in soft tissue, where target and organs at risk need accurate definition. Nevertheless, some concerns remain regarding the additional time needed to re-optimize dose distributions online, the reliability of the gating and tracking procedures and the interpretation of functional MR imaging markers and their potential changes during the course of treatment. Due to its continuous technological improvement and rapid clinical large-scale application in several anatomical settings, further studies may confirm the potential disruptive role of MRgRT in the evolving oncological environment. Advanced radiation techniques, including intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) or high-dose stereotactic body radiotherapy (SBRT) pursue the goal of delivering high doses to the tumor, while sparing the surrounding tissues and organs at risk (OARs). To ensure a precise dose delivery, image-guided radiotherapy (IGRT) has been developed and widely introduced into clinical practice. Current IGRT techniques using on-board cone-beam CT (CBCT) are already very effective, but are limited due to the reduced soft-tissue contrast. Frequently, it remains challenging to distinguish tumor from normal tissues, with the consequence that dose escalation strategies are not readily feasible, or generous planning target volume (PTV) margins are applied to account for uncertainties in gross tumor volume (GTV) delineation, dose delivery and target coverage.On-board real-time Magnetic Resonance Imaging (MRI)-guided radiotherapy (MRgRT) with hybrid MR-linear accelerator (MRL) systems marks the beginning of a new era. MRI is the most versatile and suitable imaging modality for RT, as it provides direct visualization of the tumor and surrounding tissue anatomy. Moreover, it provides real-time imaging to characterize and eventually track anatomical motion. Respiratory gating by MRI is particularly advantageous in several aspects for high dose SBRT , 2. It eSuccessful translation of new technologies into clinical practice remains challenging. To date, the initial availability of next-generation hybrid MR-linac systems is still limited and therefore, the focus of the present preview is on the initial applicability in current clinical practice and on future perspectives of this new technology for different treatment sites.Tumors of the central nervous system (CNS) are frequently treated with RT. Specific entities are metastases, primary brain tumors , extra-axial tumors such as meningioma, and other benign entities including pituitary adenomas and vestibular schwannomas. A MRI-based planning workflow could potentially be both, cost- and time-saving while reducing uncertainties associated with CT-MRI registration . MRI alrHowever, a crucial difference emerges: the MRL systems enable a rapid adaptation, immediate target volume delineation  and quicIn summary, MRgRT creates a new perspective towards an individualized, patient-centric planning approach using online adaptation for intracranial treatments. Furthermore, a significant increase in knowledge is expected concerning the biological processes, which occur during RT and its effect on patient survival for brain diseases.MRI is increasingly used in head and neck (H&N) RT due to its superior soft tissue contrast and its versatility. MRI is utilized in treatment planning to delineate the GTV , the cliDuring the course of irradiation, H&N patients can significantly lose weight and OARs, such as the parotid glands can dramatically shrink . The timTumor response varies from significant volumetric changes of large lymph nodes to more subtle MR signal changes within the GTV. When the tumor clearly shrinks and is replaced by healthy tissue, the GTV might be adapted in a straightforward manner . How to H&N cancer patients are treated using an immobilization mask that, in combination with the several rigid bony structures, minimize major intrafraction motion. However, considerable motion has been observed for the larynx and the tongue due to breathing, movement of the tongue and swallowing . Cine-MRCurative treatment schemes for H&N cancer patients usually consist of 30 to 35 fractions. Full online plan optimization including the registration, adaptation, optimization and QA steps currently takes approximately 45 min [Non-small-cell lung cancer (NSCLC) histology accounts for approximately 85% of all lung cancer cases. Of these, almost 30% present with locally advanced disease, and RT in combination with chemotherapy represents the treatment of choice for this patient group –19. BecaSBRT is a well-established technique for the management of stage I NSCLC, which has significantly improved local control (LC) in comparison to conventional fractionation. LC rates of ≥85% are achieved when the prescribed biologically equivalent tumor dose is ≥100 Gy –29. It iIn summary, MgRT offers improved accuracy of the target position by means of superior intra-fraction tumor visualization. MRgRT is expected to achieve prolonged disease-free survival and lower toxicity for thoracic lung tumors, especially in the field of re-irradiation and in the management of centrally located lesions, by using better intra-fraction motion management in combination with online plan adaptation.The standard of care for patients with early breast cancer after breast conserving surgery is whole breast irradiation , 41. RecA possible concern of the inconclusive data are differences in target volume delineation, the dosimetric characteristics and the dose-fractionation schedules of the various APBI techniques. Localization and delineation of the CTV on a postoperative CT remains difficult, even if additional clips are placed in the tumor bed. Furthermore, additional margins must be added to the CTV to account for chest wall movement and patient set-up in External Beam RT (EBRT), which may result in larger irradiated volumes in EBRT compared to brachytherapy or intra-operative APBI techniques , 47. Then = 8), 18 Gy (n = 8) or 21 Gy (n = 16) and lumpectomy was performed within 10 days. The CTV was delineated using a planning MRI, and included the GTV with an isotropic margin of 15 mm. Overall, no acute dose-limiting grade 3 radiation-related toxicities were reported. These early results seem encouraging and represent a first step toward a novel APBI approach [Another approach could be the preoperative MRgRT APBI. Preoperative target delineation showed to have less inter-observer variation as compared to the postoperative setting , 50. MRIapproach .In summary, set-up margins can be further reduced, as no co-registration of planning MRI and CT is required and dose delivery can be performed using respiratory gated MRgRT. This approach can reduce irradiated breast volume and therefore normal tissue toxicity, as cardiac toxicity , 54. MorLiver represents an intriguing anatomic site of application for MRgRT SBRT due to the increasing utilization of MRI in the characterization of primary and secondary hepatic lesions and the emergent role of SBRT in their management , 56. KisFurthermore, MRI real-time 2-Dimension gating imaging can efficaciously manage treatment volumes movements through direct and/or indirect gating approaches and overcome the necessity of invasive fiducials implantation . DespiteThe anatomical characteristics and location of the pancreas make it difficult to find the balance between target coverage and OAR sparing, especially in the SBRT setting. Available technologies for patient re-positioning and dose delivery  do not allow effective dose escalation of the target and toxicity remains a strong dose-limiting factor –66.Various studies have described the segmentation advantages and planning solutions for MRgRT in this scenario; in particular, its online adaptive approach, which appears suitable for dose escalation, plan adaptation and inter-fraction anatomical variability management , 67, 68.To date, MRI represents the gold standard technique in rectal cancer diagnosis, due to its excellent soft tissue contrast and high spatial resolution. The integration of this kind of imaging in hybrid MRgRT solutions opens up new frontiers for segmentation and dose escalation protocols . FurtherClinical studies on rectal cancer MRgRT are not yet available in literature, but its feasibility and safety in the neoadjuvant setting have been evaluated. Treatment plans of the Tri-60-Co MRL systems reach comparable target coverage, although larger volumes of OARs  receive higher low-moderate doses as compared to standard intensity-modulated RT technologies . These rAlthough renal cell carcinoma (RCC) has historically been considered a radioresistant entity, and RT has been usually applied with palliative intent, recent technological advancements are allowing radiation oncologists to introduce RT with a curative intent also in this setting. Ongoing studies confirming the safety and efficacy of preliminary reported data are likely to open a scenario, in the near future, that integrates SBRT into the therapeutic algorithm of primary RCC , 75.Nevertheless, the kidney is affected by large intra-fraction respiratory variations that can dramatically change during the treatment of daily fractionation –80. StemIn summary, considering the previous discussed uncertainties related to respiratory variations and the individual anatomy conformation of the region of interests, kidney tumor irradiation by MRL seems promising. MRgRT for primary and metastatic tumors in the kidney may represent a new tool to expand its therapeutic application in the near future, although it is still under development due to the paucity of available clinical data.RT has a well-defined role in the management of organ-confined prostate cancer and is considered a standard curative treatment option, especially in the era of dose escalation and hypofractionation by IMRT and IGRT, and more recently by means of SBRT . DespiteIn fact, the most interesting benefit in prostate cancer RT is undoubtedly represented by the ability to perform daily adaptive replanning. With conventional IGRT, there are no possibilities to compensate for the independent movements of the prostate volume. At the beginning of the treatment, RT can induce a volumetric increase of the prostate gland followed by a decrease towards the end of the treatment . In caseIn summary, the recent developments of MRgRT systems open up new perspectives for RT in prostate cancer by enabling adaptive and on-line tracking strategies, especially when extremely high doses per fraction are prescribed. Furthermore, the capability to produce high quality MR sequences during and after the treatment, will probably further change the perspective of the MRI availability in this setting, opening an unexplored window on the landscape of radiomics for prostate cancer RT.Radical cystectomy and RT (with or without chemotherapy), are the two main treatment approaches for muscle-invasive bladder cancer . HistoriHowever, one of the main criticisms regarding RT in bladder cancer is related to organ motion management. The bladder is a hollow mobile organ, seriously affected by changes in size and position during RT. This can dramatically impact daily dose coverage of the bladder tumor and OARs sparing, limiting the reliability and reproducibility of the entire RT –102. To In order to check and correct the position, size and shape of the bladder for each treatment fraction, a high quality 3D image acquisition using CBCT has been introduced in clinical practice , 106. VeIn summary, although some concerns remain in regard to the additional time needed to carry out online dose distribution re-optimization, the advent of MRL systems will undoubtedly improve bladder cancer adaptive RT strategies, reinforcing its indication in this setting .Standard therapy for locally advanced cervical cancer is a combination of concurrent chemo-RT followed by brachytherapy . DespiteDue to its excellent soft-tissue contrast, MRI is already widely applied for staging and post-treatment evaluation of cervical cancer, as it is superior in assessing tumor size as well as soft tissue invasion compared to conventional CT imaging , 112. HoMRgRT with its superior soft-tissue contrast allowing for precise and immediate detection of inter-fractional organ motion as well as tumor shrinkage in response to therapy includes the potential of reducing toxicity and potentiating dose escalation in EBRT for cervical cancer , 121. FuIn summary, MRg RT for cervical cancer can represent a promising tool to overcome the limits of conventional IGRT systems, in order to improve daily adaptive RT strategies. Further studies can confirm its potential disruptive role in this setting.Metastatic solid cancer was long considered incurable and treatment consisted mainly of palliative chemotherapy. Local treatments, such as surgery or radiotherapy, with palliative, non-ablative doses were restricted to symptom control. The concept of oligometastatic disease (OMD) is currently challenging this dogma by defining an intermediate state of metastasized disease, with a more favorable disease biology and dynamic. OMD is characterized by a limited number of metastatic lesions and a low overall metastatic burden that opens a therapeutic window for radical treatment to all metastatic sites. Originally coined by Hellman and Weichselbaum in 1995 , the ideIn the treatment of oligometastatic disease, early efforts have mainly focused on the radical treatment of readily resectable lesions, like brain and adrenal metastases. With the improvement in diagnostic imaging and novel developments in non-invasive LAT modalities such as SBRT, prospective reports have surfaced recently that investigate radical treatment of all disease sites, potentially leading to improved clinical outcome –136. StiIn a recent review on SBRT for lymph node (LN) metastases, Jereczek-Fossa et al. reported local control rates of 64% up to 98% at 3 years . A clearIn the oligometastatic setting, radical treatment of adrenal metastases in the form of surgical resection is a well-established indication. Reports on CT guided SBRT have emerged with very encouraging local response rates, as long as the tumors can be readily visualized and a sufficient ablative radiation dose can be delivered , 143. LoIn summary, MRgRT can be considered a groundbreaking new technology that is capable of creating new perspectives towards an individualized, patient-oriented planning and treatment approach, especially due to the ability to use daily online adaptation strategies. Furthermore, MRL systems overcome the limitations of conventional IGRT, especially in soft tissue, where target and OARs need accurate definition. Nevertheless, some concerns remain concerning the additional time needed to re-optimize dose distributions online, the reliability of the gating and tracking procedures and the interpretation of functional MR imaging markers and their potential changes during the course of treatment. Due to its continuous technological improvement and rapid clinical large-scale application in several anatomical settings, further studies may confirm the potential disruptive role of MRgRT in the evolving oncological environment.


The superficial temporal artery (STA) plays a very important role in neurovascular diseases and procedures. However, until now, no comprehensive review of the role of STA in neurovascular diseases from a neurosurgical perspective has ever been published. To review research on the clinical importance of STA in neurovascular diseases, a literature search was performed using the PubMed database. Articles were screened for suitability and data relevance. This paper was organized following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. According to the literature, STA is one of the terminal branches of the external carotid artery and can give off scalp, muscle, and transosseous branches. STA-middle cerebral artery (MCA) bypass is very useful for intracranial ischemic diseases, including moyamoya disease, chronic ICA and MCA insufficiency, and even acute ischemic stroke. For intracranial complex aneurysms, STA bypass remains a major option that can serve as flow replacement bypass during aneurysmal trapping or insurance bypass during temporary parent artery occlusion. Occasionally, the STA can also be involved in dural AVFs (DAVFs) via to its transosseous branches. In addition, the STA can be used as an intraoperative angiography path and the path to provide endovascular treatments. Therefore, STA is a very important artery in neurovascular diseases. The superficial temporal artery (STA) is one of the terminal branches of the external carotid artery (ECA), and it together with other branches of the ECA, supplies the face and scalp Therefore, a comprehensive understanding of the role of STA in neurovascular diseases is important for multiple disciplines th 2019).This systematic review was conducted in accordance with the PRISMA guidelines The search algorithm used the terms “superficial temporal artery,” “ischemic disease”, “moyamoya disease”, “aneurysm”, and “arteriovenous fistula” as key words in relevant combinations. The reference lists of the identified articles were also manually searched for additional studies. The resulting flow chart is shown in Figure The inclusion criteria were as follows: a) full text was available, b) clinical data were complete, and c) STA was involved or used in all of the cases in these articles. The studies without sufficient descriptions of the STA role were excluded.After a review of the obtained literature, the current status of the role of STA in neurovascular diseases was summarized in terms of the anatomy of STA, bypass for intracranial ischemic diseases, bypass for intracranial complex aneurysms, STA aneurysm, direct AVF, DAVF, and intraoperative angiography and EVTs.The STA originates from the ECA deep to the superficial pole of the parotid and ascends approximately 1 cm anterior to the auditory canal The frontal branch of the STA supplies the skin and muscles of the forehead and anastomoses with the supraorbital and supratrochlear arteries, and the parietal branch supplies the temporal and parietal regions The STA has a suitable length and diameter The anatomy of the STA can be evaluated via computed tomographic angiography (CTA) and DSA Moyamoya disease (MMD) is characterized by progressive stenosis or occlusion of the terminal portion of the bilateral internal carotid arteries (ICAs) with extensive and abnormal moyamoya-like collaterals in the brain base Currently, the strongest agreement regarding treatment for symptomatic MMD in the chronic phase is extracranial-intracranial (EC-IC) bypass, including direct bypass and indirect encephaloduroarteriosynangiosis Indirect procedures can result in excellent results in children with MMD and have therefore been widely used Direct EC-IC bypass includes STA-middle cerebral artery (MCA), STA-anterior cerebral artery (ACA), STA-posterior cerebral artery (PCA), and occipital artery (OA)-PCA anastomoses, among which STA-MCA bypass is the most common direct revascularization procedure. It is mainly used to address the MCA territory but also supports the ACA territory via leptomeningeal anastomoses STA-MCA bypass is typically performed using only a single STA donor branch to perform a single anastomosis. Recently, single-vessel double anastomosis and double-barrel STA-MCA bypass appeared Although STA-MCA bypass has been described as a low-flow system, it is sufficient for MMD Theoretically, STA-MCA bypass can be used to treat symptomatic atherosclerotic disease of the ICA and MCA However, the trial published in the New England Journal of Medicine failed to stratify patients by risk to determine which would receive the greatest benefit from this intervention Therefore, theoretically, some carefully selected patients could still benefit from STA-MCA bypass In addition, in chronic ICA and MCA insufficiency, these bypasses increase blood flow, such as the STA trunk to MCA bypass with short radial artery or STA-MCA double anastomoses, and may also be effective for providing neurological improvement in symptomatic atherosclerotic disease of the ICA and MCA In acute ischemic stroke (AIS) resulting from atherosclerotic occlusion of the ICA or MCA, the role of STA-MCA bypass remains poorly understood; for example, it remains unknown whether STA-MCA bypass provide any beneficial effects in affected patients Recently, Rice et al. (2018) performed a study of a large series and found that STA-MCA bypass, when performed in a setting of symptomatic AIS within 1 week, may confer a higher risk of perioperative stroke, including progression of ischemia or hemorrhagic transformation. Patients undergoing urgent bypass for unstable stroke symptoms might have the highest risk for perioperative stroke However, Hwang et al. (2011) found that STA-MCA bypass may be beneficial in AIS or stroke showing progress of a small infarction Therefore, for STA-MCA bypass performed in AIS, the mainstream belief is that acutely symptomatic patients with ICA or MCA occlusion who continue to have recurrent ischemic symptoms may, in a very few selected cases, be indicated for a bypass, although a low-flow procedure is a far better bypass than a high-flow procedure in the setting of an acute stroke when the aim is to limit hemorrhagic complications Complex aneurysms include large aneurysms, those with involvement of perforators, those from which branch arteries originate, or those that represent refractory lesions In cerebral revascularizations, STA could serve as a donor vessel for low flow bypasses, which include STA-MCA, STA-anterior cerebral artery (ACA), and STA-superior cerebellar artery (SCA). In STA-ACA bypass, of note, an interposition graft may be needed for the long anatomical distance between STA and ACA. In case of high flow bypass between flow internal maxillary artery (IMA) and MCA, ACA, PCA, or ICA, STA can be used as an interposition vessel. STA-MCA bypass is most suitable for complex MCA and ICA aneurysms when the recipient is the M3/M4 segment STA-MCA bypass is the standard mode of cerebral revascularization in complex MCA and ICA aneurysms. However, STA-MCA bypass provides a low-flow system, and insufficient blood flow may result in negative events following therapeutic occlusion of the main trunk arteries that should be replaced by high-flow revascularization The internal maxillary artery (IMA) is suitable to provide sufficient blood flow, and the STA trunk graft can be used for bypass of the IMA to proximal MCA in complex aneurysms In addition, with a larger caliber, the STA trunk can provide more blood flow than the distal STA branches do. Hence, STA trunk-to-M2 of MCA or proximal PCA high-flow bypass with a short radial artery interposition graft should not be forgotten as it represents an excellent bypass to add to the armamentarium of choices when considering bypass options for complex aneurysms DAVF is an arteriovenous shunt located in the dural wall. The meningeal branches of the ECA and ICA are the main feeding arteries in DAVFs, with the middle meningeal artery (MMA) and OA the most commonly involved Currently, in DAVF embolization, the STA is known to be poorly suitable because a pressure gradient of its transosseous branches may limit embolic agent penetration toward the shunt point In neurovascular diseases, intraoperative angiography is very useful for evaluating surgical clipping/excision and determining whether any residual lesion remains The STA is a good path for intraoperative angiography Finally, the STA can be used as the path to perform EVTs This PRISMA-compliant systematic review of the clinical importance of STA in neurovascular diseases shows that the STA is one of the terminal branches of the external carotid artery and that it gives off many branches that supply the scalp and muscles. STA-MCA bypass is very useful for intracranial ischemic diseases. For intracranial complex aneurysms, STA bypass remains a major option that can serve as flow replacement bypass during aneurysmal trapping or insurance bypass during temporary parent artery occlusion. Occasionally, the STA can be involved in DAVFs via its transosseous branches. In addition, the STA can be used as a path for intraoperative angiography or performing an EVT procedure. Therefore, the STA is a very important artery in neurovascular diseases.