Cholesterol-overloaded cells or “foam cells” in the artery wall are the biochemical hallmark of atherosclerosis, and are responsible for much of the growth, inflammation and susceptibility to rupture of atherosclerotic lesions. While it has previously been thought that macrophages are the main contributor to the foam cell population, recent evidence indicates arterial smooth muscle cells (SMCs) are the source of the majority of foam cells in both human and murine atherosclerosis. This review outlines the timeline, site of appearance and proximity of SMCs and macrophages with lipids in human and mouse atherosclerosis, and likely interactions between SMCs and macrophages that promote foam cell formation and removal by both cell types. An understanding of these SMC-macrophage interactions in foam cell formation and regression is expected to provide new therapeutic targets to reduce the burden of atherosclerosis for the prevention of coronary heart disease, stroke and peripheral vascular disease. Smooth muscle cells (SMCs) and macrophages form the bulk of the cells in all stages of human and mouse atherosclerosis. Studies since the early 1990’s have mostly used mice to study atherogenesis, and have suggested that this process is primarily macrophage-driven, is a consequence of the endothelial damage caused by the severe dyslipidemia required to induce atherosclerosis in these animals, and that SMCs play a lesser role . In contMice are the most widely used animal model for the study of atherosclerosis, due to their short developmental and life cycle, ease of genetic modification, low-cost rearing, small size and high reproductive rate. However, mice and humans exhibit significant genetic and physiologic differences influencing major steps in the process of atherogenesis.Wild-type (WT) mice do not develop spontaneous atherosclerosis owing in part to their low-fat diet, low plasma cholesterol and overall atheroprotective lipoprotein metabolism . In partThese major differences between may lead to inaccurate assumptions of what drives early as well as later stages of atherosclerosis in humans when comparing results with mice. Hereafter, we describe the appearance and pathological mechanisms involving SMCs and macrophages and their interactions from the pre-atherosclerotic stage to the advanced plaque in these two species.Atherosclerosis is a disease of medium and large size arteries that progresses from the initial deposition and accumulation of lipids derived from circulating apoB-containing lipoproteins in the already formed DIT layer of SMCs and proteoglycans of atherosclerosis-prone arteries. Nakashima and co-workers described elegantly the chronological stages of pre-atherosclerotic DIT, lipid infiltration and retention, macrophage recruitment, and pathological intimal thickening (PIT) as the last stage before progression to an advanced lesion .Certain mammalian species including humans and non-human primates but not mice, rat or rabbits, exhibit DIT in all atherosclerosis-prone arteries of their vascular system . The criSMCs particularly in the deeper intima secrete high levels of the negatively charged proteoglycans biglycan and decorin . AccordiFatty streaks are visually recognizable by the deformation and thickening of the intima towards the arterial lumen, though, in this early stage of atherosclerosis, most of this lipid is deposited in the deep intima surrounding SMCs, as well as being internalized in SMC foam cells . WhetherIn pathological intimal thickening (PIT), lipid-laden and non-lipid-laden macrophages may infiltrate more abundantly down to the middle of the intima . InteresRegarding the relative contribution of SMCs and macrophages to the foam cell population, early studies suggested, based on the microscopic appearance of lesions and staining for SMCs and macrophages, that SMCs contribute the majority of these cells in fatty streaks and PIT . AllahveThe stages of development and relative contribution of SMCs and macrophages to the foam cell population in humans are indicated in the The genetic manipulation of mice to generate atherosclerosis requires severe dyslipidemia, as achieved in models including apoE- and LDLR-KO mice on a C57BL/6 background who are also fed a high fat and cholesterol diet. The severe circulating dyslipidemia thus created itself represents a highly inflammatory environment for the vascular endothelium, in which immune cells such as monocytes/macrophages are rapidly recruited and have the predominant role in initiating atherogenesis . The absvia proteoglycan secretion in humans, their absence in mouse intima is not accompanied by the absence of extracellular matrix proteins nor lipid retention. Indeed, in 3 week-old-only apoE KO mice fed a chow diet, As indicated above, SMCs, and DIT are not present in the intima of mouse aorta or other arteries, with SMCs only appearing following induction of atherogenesis. Although SMCs are strongly implicated in lipoprotein retention Our lab has characterized foam cells in the aortic arch of non-lineage tracing and SMC-lineage tracing apoE KO mice using leukocyte-specific markers, neutral lipid staining and flow cytometry. In mice fed a Western diet for just 6 weeks, 70% of total foam cells were SMC- derived . This waThe stages of development and the relative contribution of macrophages and SMCs to the foam cell population in mice are indicated in the While arterial SMCs in humans and mice can express macrophage markers as they dedifferentiate from contractile to synthetic, intimal-type SMCs , they neLDLR gene  degraded the aggregate extracellularly into free cholesterol  molecules are covalently linked . It was rophages .. Recently, Ng and colleagues also identified that perlecan was the major proteoglycan secreted by human macrophages involved in LDL retention, though perlecan was also suggested to be low in human lesions  secreted by SMCs was responsible for contact-independent CD36 upregulation in monocytes, while vascular adhesion molecule-1 (VCAM-1) on SMCs was responsible for contact-dependent CD36 upregulation in monocytes  and therefore cannot capture fully the artery wall structure and dynamics observed in vivo, such as blood flow and extracellular matrix , achieved through the action of intracellular oxysterols binding to liver X receptor (LXR) nuclear receptors on the promoter region of the  nucleus . Additio nucleus . We prev nucleus ; in huma nucleus . As suchLipa, responsible for LAL expression, when compared to macrophages in both species  on the surface of macrophages, which blocks SMC-secreted ligand C-X-C motif chemokine ligand 10 (CXCL10) from activating CXCR3 to drive monocyte retention and inflammation . In vivoion area . An addiion area . Similarion area . FurtherIn both humans and mice, the relative contribution of SMCs and macrophages, the timing of their appearance, and their relative proximity to each other and deposited lipids in the artery wall are all key determinants of the initiation and progression of atherosclerosis. A clearer understanding of these steps and the interactions between SMCs and macrophages that influence foam cell development and regression are likely to provide fertile ground in the years ahead for development of novel treatments that will reduce ischemic vascular disease beyond what is possible with currently available treatments.


Pregnancy and the postnatal period can be a time of increased psychological distress, which can be detrimental to both the mother and the developing child. Digital interventions are cost-effective and accessible tools to support positive mental health in women during the perinatal period. Although studies report efficacy, a key concern regarding web-based interventions is the lack of engagement leading to drop out, lack of participation, or reduced potential intervention benefits.This systematic review aimed to understand the reporting and levels of engagement in studies of digital psychological mental health or well-being interventions administered during the perinatal period. Specific objectives were to understand how studies report engagement across 4 domains specified in the Connect, Attend, Participate, and Enact (CAPE) model, make recommendations on best practices to report engagement in digital mental health interventions (DMHIs), and understand levels of engagement in intervention studies in this area. To maximize the utility of this systematic review, we intended to develop practical tools for public health use: to develop a logic model to reference the theory of change, evaluate the studies using the CAPE framework, and develop a guide for future data collection to enable consistent reporting in digital interventions.This systematic review used the Cochrane Synthesis Without Meta-analysis reporting guidelines. This study aimed to identify studies reporting DMHIs delivered during the perinatal period in women with subclinical mood symptoms. A systematic database search was used to identify relevant papers using the Ovid Platform for MEDLINE, PsycINFO, EMBASE, Scopus, Web of Science, and Medical Subject Headings on Demand for all English-language articles published in the past 10 years.Searches generated a database of 3473 potentially eligible studies, with a final selection of 16 (0.46%) studies grouped by study design. Participant engagement was evaluated using the CAPE framework and comparable variables were described. All studies reported at least one engagement metric. However, the measures used were inconsistent, which may have contributed to the wide-ranging results. There was insufficient reporting for enactment , with only 38% (6/16) of studies clearly recording longer-term practice through postintervention interviews. The logic model proposes ways of conceptualizing and reporting engagement details in DMHIs more consistently in the future.The perinatal period is the optimal time to intervene with strength-based digital tools to build positive mental health. Despite the growing number of studies on digital interventions, few robustly explore engagement, and there is limited evidence of long-term skill use beyond the intervention period. Our results indicate variability in the reporting of both short- and long-term participant engagement behaviors, and we recommend the adoption of standardized reporting metrics in future digital interventions.PROSPERO CRD42020162283; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=162283 Pregnancy, delivery, and the postnatal period can be times of increased psychological distress  , and up Health promotion strategies aim to enable optimal health and skills to cope with adversity in well subclinical populations. Therefore, it is important that efforts are made not only to deal with illness but also to develop individuals’ emotional skills that can be applied in everyday life . PsycholAlthough a recent systematic review provided preliminary evidence that web-based interventions can be a promising and advisable form of intervention during the prenatal period , there ihomework are ways of helping participants develop intervention skills that can be applied, practiced, and sustained [Dropout from the intervention and loss to follow-up reduces the treatment effect . Althougustained , it is uustained  and how It is widely accepted that the full benefit of many effective treatments can be achieved only if the prescribed regime is followed reasonably closely . Recent connect pertains to how many people express interest in engaging in an intervention out of those eligible. Second, attend refers to continuous presence, such as the number of intervention sessions a participant completes. Third, participate is the degree to which participants actively engage with the content of the intervention, such as completing intervention tasks and remaining in the program. The final component, enact, refers to the participant making use of intervention strategies or knowledge as part of their daily life. Although this was developed to guide face-to-face parenting program engagement research, it can be readily applied to understanding and measuring digital intervention engagement in a research context.One of the frameworks for evaluating engagement in face-to-face programs, which can be adapted to web-based programs, is the Connect, Attend, Participate, and Enact (CAPE) model . The CAPAt a time when public resources are strained, policy makers and program administrators are looking to invest in effective, engaging prevention programs supported by scientific evidence and delivering long-term benefits. Intervention engagement must be foremost among these considerations, as this will ultimately determine the degree to which the target population takes up and benefits from the intervention when implemented in the community. Systematic reviews are an influential decision-making tool as they summarize a body of scientific research; identify implications for policy and practice ,27; and This systematic review aimed to understand the reporting and levels of engagement in studies of web-based psychological mental health or well-being interventions administered in the perinatal period to women with subclinical mood symptoms.Specifically, we aimed to (1) understand how studies report engagement, with engagement defined as containing the 4 steps in the CAPE model; (2) make recommendations on best practices to report engagement in DMHIs based on this; and (3) understand levels of engagement in intervention studies in this area.To maximize the utility of this systematic review, we intended to develop practical tools for future public health use: to develop a logic model from the literature to reference the theory of change, evaluate the studies using the CAPE framework, and develop a guide for future data collection to enable consistent engagement reporting in web-based (and offline) interventions.The methods used in this systematic review combine standard rigorous and transparent review methods using the Cochrane Synthesis Without Meta-analysis (SWiM) reporting guidelines  in conjuThe review question, search strategy, inclusion criteria, and methods were registered in PROSPERO . The research question was as follows: what is known about engagement in digital mental health and well-being programs for women in the perinatal period? A systematic database search was conducted to identify papers relevant to the aims of this review. The initial search was performed by the first reviewer (JAD), using the Ovid Platform for MEDLINE, PsycINFO, EMBASE on the EBSCO Platform, Scopus, Web of Science, and Medical Subject Headings on Demand for all English-language articles published in the past 10 years . Keywords and index terms identified as relevant in the search strategy were used and individual search criteria were developed for each database. All the database search strategies are provided in The search strategy aimed to identify studies reporting on engagement and retention in digital mental health and well-being programs for women during and after pregnancy. Clear inclusion and exclusion criteria were developed using the Population, Intervention, Comparison, Outcomes, and Study framework to guide the inclusion criteria for participants, intervention or phenomena of interest, comparators, outcomes, study design, and context .Inclusion criteriaParticipantsChildbearing individuals in the perinatal period Studies focusing predominantly on the childbearing individual but can include partnersStudies that include childbearing individuals at moderate risk for psychological distress Studies that include women at risk of postnatal depression with a history of depression or anxiety InterventionAny minimal contact digital interventions provided in the perinatal period aiming to reduce mild to moderate psychological distress or promote psychological well-being ComparatorsStudies with any form of comparator were consideredOutcomesNone; although the focus of the review was on engagement outcomes, we included any studies of interventions meeting the above criteria to determine the proportion that reported engagement outcomesStudy designQuantitative , and qualitative studiesExclusion criteriaParticipantsStudies considering programs before conception and those specifically targeting the childStudies focusing predominantly on the partner or fatherStudies that include women at high risk for psychological distress InterventionInterventions with a primary focus other than mental health or well-being Interventions delivered face to face or as telehealth or telephone coachingAll papers that appeared eligible based on their title and abstract were retrieved for screening. The first author (JAD) reviewed the titles and abstracts of all papers, assessed eligibility, and noted any reasons for exclusion. Full-text articles were assessed for eligibility and reviewed independently by both the first author (JAD) and third author (LYG). Once the third author (LYG) had reviewed the papers, any discrepancies were resolved through team discussion. The reference lists of the included studies were examined to identify additional relevant papers.Key article characteristics were recorded using a Microsoft Excel (version 2020) data extraction table developed for this review. These characteristics included general information about the study, such as the country and author, along with specific information about the study design, comparators, and intervention type. Coding of the study characteristics enabled us to group the studies as part of our synthesis. As our primary aim was to understand the engagement of the study population, we characterized the assessment time points, engagement measures, and reporting of attrition and adherence. Data relevant to engagement were extracted using the CAPE framework; this included variables for recruitment, retention, attrition, and follow-up time points. A framework analysis methodology  was usedLogic models can help conceptualize a complex review question and specify analytic links to test the plausibility that a program works as intended . Logic mThe risk of bias for studies included in this review was based on the Cochrane Collaboration’s tool for assessing the risk of bias for each category of study , and the risk of bias was adapted for this review and classified as low, uncertain, or high based on the Cochrane risk of bias tool  and the As this systematic review synthesized the results from a diverse range of interventions, we used SWiM guidelines  to promoSummarized the characteristics of each study and reported intervention implementation, recruitment and engagement activities, study findings, reported attrition, and methodological qualityDetermined which studies were similar enough to be grouped within each comparison by comparing across studies Determined which data were available for synthesisSynthesized the characteristics of the studiesPerformed a statistical synthesis for appropriate quantitative data and comprehensive critical appraisal through a meta-synthesis approach for qualitative dataFor each trial included in this systematic review, we recorded counts of trial participants who were assessed for eligibility, those who were recruited, and those who were allocated to the intervention and control arms; rates of recruitment, trial completion, and loss to follow-up were synthesized by evaluating the proportion of recruitment, completeness, and loss to follow-up in base R  statistical package ; synthesThe electronic searches generated a database of 3473 potentially eligible studies that were assessed using the review eligibility criteria. After duplicates were removed , all titles and abstracts were screened for eligibility. In total, of the 3473 studies, 2795 (80.48%) records were screened, and 2654 (76.42%) were excluded based on the inclusion or exclusion criteria . After tThe literature search and inclusion processes are detailed in the PRISMA  flow diagram . The seaThe primary aim of this systematic review was to assess the engagement of women participating in digital mental health or well-being interventions; therefore, the standardized metric and transformation method  used acrIn all groups, there was a range of therapeutic approaches, including cognitive behavioral therapy, parenting education, positive psychology, mindfulness, and compassion-based training. Several studies used a psychoeducation approach to build parenting self-efficacy, such as Chan et al , Shorey Participant engagement was evaluated using the CAPE model of engagement , which iConnect was operationally defined as the proportion of participants who entered the study and started the intervention relative to those who were aware of the study. Although many studies reported the exposure methods for the target audience, for example, advertising via Facebook, Twitter, web-based email lists, community sites , and third-party websites , there rd et al  reportedAll studies in this review reported enrollment rates in the intervention, which we defined as those who commenced the intervention relative to those who expressed interest in the study. Conversion to commencement was based on multiple factors, not just the participants’ decision to engage, both dependent and independent of the inclusion or exclusion criteria. Most studies in this review reported reasons for exclusion, ranging from lack of contact or completion of baseline surveys to elevated mental distress scores. Enrollment rates varied from a high rate of 82%  or similar, such as the number of participants who completed all web-based interventions. This information was not stated in any of the studies included in this review. As a result, we calculated a proxy for intervention attendance as study attendance, operationally defined as intervention retention and continuous presence (continued interaction with the intervention), in both the intervention and control arms (where controls were used). All studies reported retention in terms of the rate of those who enrolled versus those who completed the study.In face-to-face interventions, The highest reported study retention (groups 1 and 3) was reported by Ayers et al  at 90%. In the control arm, Guo et al  had the Participation was operationally defined as the completion of intervention activities; that is, active engagement with the intervention material. Follow-up prompts to encourage participation varied across studies; however, there were mostly weekly reminders such as SMS text messages, emails, and phone calls. A broad spectrum of metrics was used to report ongoing participation in each study, including module views, module and home practice completions, engagement with web-based components, use of the app (frequency of log-ins) and other relevant services , number and duration of support calls, and web-based diary entries. The heterogeneous nature of recording these activities is appropriate for the types of intervention strategies but limits our ability to consistently report and compare across studies.The limited follow-up period restricted our ability to report against measures indicating that participants applied and practiced learning skills . ImmediaThrough the analysis and reporting of each study, we recorded the types of quantitative and qualitative measures found in the selected studies that could be used to measure engagement. This enabled us to systematically construct a logic model based on our understanding of how interventions are expected to work. This was particularly pertinent for this systematic review as we did not perform a meta-analysis. As indicated, we grouped variables related to the CAPE framework; the logic model includes a range of metrics that could be systematically reported when synthesizing engagement data to visually interpret the underlying theory of change.The logic model  containsAs part of this systematic review, we aimed to develop a guide for future data collection to enable consistent engagement reporting in web-based (and offline) interventions. connection, attendance, participation, and enactment. Reporting of connection and attendance measures was fairly standardized across studies and frequently reported using a CONSORT diagram; therefore, the number of people who were eligible and expressed interest in participating, proportion of participants recruited and entered in the study, and proportion of participants who were randomized and followed up, including treatment not started and attrition rates, was clear. Approximately 75% (12/16) of studies, provided a CONSORT participant flow diagram (indicating aspects of attendance); however, the reporting categories and terminology varied between diagrams. In general, the least frequently reported domain was enactment , with only 38% (6/16) of studies clearly recording and reporting results such as satisfaction, usefulness, helpfulness, and perceived benefits of the skills learned in the intervention.In this systematic review, we categorized the selected studies according to study type and assessed their individual and pooled characteristics. We applied the CAPE framework  to all sconnection. For example, Ashford et al [Some studies reported strategies to increase rd et al  includedrd et al ). No stuattendance is a measure of DMHI completion through modules or similar exercises. As this was not definitively reported, for attendance, we calculated a proxy for intervention attendance as study attendance, operationally defined as intervention retention and continuous presence, both in the intervention and control arms (RCTs). Guo et al [attendance by reducing attrition and improving retention; however, dropout from baseline assessments to 6 weeks post partum was high (63%) [intervention attendance and study attendance as they are distinct metrics.As previously defined, uo et al  had the uo et al  undertoogh (63%) . We recoparticipation [A key concern in web-based interventions is the lack of cipation . Logs ofcipation  suggest,cipation  quantificipation  and Barrcipation . Other scipation . These fEnactment is difficult to define but should be represented by measures indicating that participants put what they learned from the program into practice [practice . The limpractice , followepractice ,33,35-37practice ,44. AlthUnderstanding the barriers to and enablers of real-world utility and practice is crucial if app developers want pragmatic uptake and efficacy of interventions. Sufficient resourcing may be a factor in longitudinal follow-up; however, to leverage the impact and cost-effectiveness of interventions, studies should factor longer-term assessments in the design process from conceptualization. Nevertheless, easier and low-cost measures of enactment are possible and suggested for future research, including questionnaires on the frequency of using skills taught during the intervention.As part of this review, we developed a logic model to facilitate the process of gathering and integrating studies of complex interventions to better inform our interpretations of cumulative results. The logic model included synthesized data capture and engagement methods used in each study. Theoretically, logic models need moderating or mediating factors to understand how the pathway develops. In these studies, there was a common strength-based approach, such as skill development, confidence, satisfaction, and self-efficacy. Overall, the heterogeneous nature of the data collection meant that we were unable to undertake a meta-analysis; however, the range of methods and types of data collection is useful in guiding future web-based interventions targeting this population group and helping decision-makers understand the rationale for how interventions are expected to work and what enablers keep participants engaged to ultimately achieve the intended outcomes.There is a need for a greater understanding of the individual-level, real-world factors affecting engagement in home and minimal contact practice interventions to ascertain how participants experience interventions and how this relates to their outcomes . Exit anAs the studies in this review were diverse in terms of study design, therapeutic intervention approach and delivery, length of follow-up, and outcome measures, we summarized the engagement data using the CAPE framework but were unable to perform a meta-analysis of the data. Attrition rates were high in many studies, and the number of participants was small, particularly in some pilot studies. We were unable to report this in terms of increasing our understanding of sustained practice as there was limited follow-up in most studies. There are inconsistent reports and terminology regarding engagement behavior. Inconsistencies in language between studies and interchangeability of terms, for example, attrition, withdrawal, dropout, and loss to follow-up, make direct comparison and systematic analysis challenging. Another potential limitation of this review is the lack of inclusion of studies in languages other than English. In addition, the protracted nature of systematic reviews means that the original search was concluded in 2020 and was affected by delays because of the COVID-19 pandemic. Since then, additional studies may have been published and not included in this review but would not necessarily affect our general conclusions or implications for using the logic model or reporting matrix.The ability to leverage several frameworks enhanced this systematic review. The SWiM guidelines, part of the Cochrane methods, directed our synthesis and reporting. In addition, the CAPE framework provided an evidence-based approach to reporting on intervention engagement; using this framework, we were able to propose clear metrics for future reporting. It is recommended that future research provide engagement analytics to more clearly delineate between study and intervention compliance, particularly longer-term enactment or sustained practice to reflect pragmatic efficacy. The research team has a strong focus on research translation; therefore, the incorporation of a logic model provides a clear pathway for decision-makers, such as policy makers and commissioners, to interpret and guide the key constructs and evaluation metrics in future digital interventions in this field of research.There is substantial evidence that psychological programs delivered on the web can be effective in treating and preventing mental health problems; however, the uptake of these programs can be suboptimal, and there remains a lack of evidence on how to increase engagement with evidence-based programs . Poor adAdvances in technology, particularly the internet, have proven to be an effective tool for building individual skills as it is inexpensive and accessible, both geographically and temporally. Despite promising results, internet interventions are still not widely disseminated or well-integrated into health services; successfully doing so will, in part, depend on engagement. As mental health apps have proliferated, choosing among them has become increasingly challenging for not only patients but also clinicians . To addrTo invest in accessible, long-term, sustainable health solutions, researchers, policy makers, and clinicians must identify optimal interventions that can be targeted to help specific risk groups or in specific contexts. Advances in technology, particularly the internet, have proven to be an effective tool for building individual skills as it is inexpensive and widely accessible. Pregnancy and the postnatal period can be times of increased psychological distress; therefore, it is an optimal time to intervene with strength-based tools to build affirmative self-efficacy. Although several studies in this field demonstrate efficacy, few robustly explore the construct of engagement, and in particular, there is limited evidence of the long-term enactment of the strategies learned. Our results indicate a disparity in the reporting of short- and long-term participant engagement behaviors, and we recommend the adoption of standardized metrics for reporting DMHI engagement in both research and real-world settings. This systematic review provides a framework for understanding the pathways for enhancing the mental well-being of mothers and their infants. With the world experiencing an endemic escalation in poor mental health across the life course, both in low- and high-income countries , it is i


Growth hormone (GH) is mainly secreted by eosinophils of anterior pituitary gland. GH plays an important role in regulating the growth and development of many tissues and cells, so it is used in the treatment of many diseases. In recent years, the regulation of GH on ovarian function has attracted much attention. GH has been applied in controlled ovarian hyperstimulation, particularly in the patients with advanced age, diminished ovarian reserve (DOR) and poor ovarian response (POR). GH can directly bind to the growth hormone receptor (GHR) on the ovary to promote the growth, maturation and ovulation of follicles, as well as to inhibit follicular atresia. GH so as to promote the occurrence of early follicles, enhance the sensitivity of follicles to gonadotropins, accelerate the maturation of oocyte nucleus, improve mitochondrial activity and the quality of oocytes through the insulin-like growth factor (IGF) system, which is an indirect regulation. The deep-seated effects of GH on human reproduction and ovarian aging need further basic research and clinical practice. With the development of the global economy and the transformation of women’s social roles, the childbearing age of couples around the world is increasing year by year , 2. The In recent years, studies have shown that growth hormone (GH) can promote sexual maturation and gonadal cell proliferation, improve ovarian response to gonadotropins, facilitate follicular development and maturation, regulate steroid production, enhance endometrial receptivity, as well as promote embryonic quality . It is pGH is a peptide hormone mainly secreted by acidophil cells in the anterior lobe of the adenohypophysis. While reproductive cells can also secrete a small amount of GH in a continuous manner . GH can In human peripheral blood, about 45% of GH is combined with growth hormone binding protein (GHBP). GHBP can be classified into GHBP1 with high affinity and GHBP2 with low affinity . The forGHR is a transmembrane protein in the form of heterodimers. It contains 620 amino acids, which can be expressed in reproductive system such as granulosa cells, theca cells, oocytes, cumulus cells, uterus and placenta. The human GHR gene is located at chromosome 5p12-p13.1 . GH has GH can directly affect the ovarian function through GHR. It has been found that GH and GHR are expressed (protein and mRNA) in oocytes, granulosa cells and luteal cells. GHR located on the surface of oocyte membrane, cumulus cells, granulosa cells, and cumulus oocyte complexes at early follicular . The dirin vitro culture medium of human oocytes can significantly promote the maturation of oocytes at the germinal vesicle (GV) stage after degranulation, through accelerating meiotic progression, regulating the expression of genes related to cellular redox homeostasis, and promoting oocyte developmental potential . IGFs are proteins with molecular weight of about 7.5 kDa, which are divided into type I and II. It is named for its high homology with insulin . IGFs inIGF-I and FSH in ovarian granulosa cells promote the expression of each other’s receptors, thereby mutually enhancing biological effects. After IGF-I gene of mouse was knocked out, the follicles stopped developing at the phase of preantral or early antral follicles, without ovulation . TherefoExogenous GH can increase the expression level of IGF-I, IGF-I receptor and FSH receptor in granulosa cells . IGF-I aThe aneuploidy rate of oocytes is a direct manifestation of oocyte quality. Mitochondrial function determines the quality and developmental potential of oocytes. Abnormal mitochondrial function and distribution are believed to be the cause of cell aging, especially oocyte aging. GH can up-regulate and activate GHR on the surface of the membrane of human oocytes, improve mitochondrial activity . MitochoThe reactive oxygen species (ROS) produced by oocytes under oxidative stress can lead to oxidative damage to cells, especially to nucleus and DNA . DNA damClinical study found that only increasing the dosage of gonadotropin in the COH process of patients with POR and DOR could not promote ovarian response. Some of the patients may be due to the lack of FSHR or functional mitochondria in granulosa cells . IGF-I iAdding a certain amount of GH during COH process of patients with POR can improve ovarian response, increase the number of follicles, and reduce the amount of gonadotropin . The GH So far, in most of the RCT studies about the relationship between GH supplementation and the improvement of IVF assisted pregnancy outcome in infertile women, the starting time of drug use is mostly within the ovulation induction cycle or one week ahead, and a few studies are 2 to 6 weeks before ovulation induction . The GH The medium dose of GH pretreatment to elderly experimental animals for 8 weeks in advance can improve oocyte quality by improving its mitochondrial membrane potential, distribution, and increase the number of retrieved oocytes and MII egg rate in COH. The starting time of GH usage in most RCT studies is the 21st day of the previous menstrual cycle or the first day of the COH cycle, and the stop time the HCG-Day , 34. Thein vivo and in vitro research are needed to explore and verify the role of GH in the COH cycle.Some studies have shown that although GH can reduce the dosage of Gn, shorten the duration of COH, increase the number of oocytes and transferable embryo, it does not significantly increase the clinical pregnancy and live birth rate , 33. ThePrevious studies on the adverse reactions after long-term GH treatment mainly focused on mortality, new diabetes, and the occurrence of malignant tumors and thyroid diseases . In the The basic researches on GH regulating ovarian function have laid a full theoretical foundation for its clinical application. GH plays an important role in follicular growth and development, follicular maturation, ovulation, oocyte quality and steroid hormone synthesis. The use of GH in IVF treatment can improve the outcome of assisted reproductive therapy in patients with POR, DOR and advanced age. Although there are still some disputes about increasing the clinical pregnancy rate and live birth rate. The previous clinical studies reached few precise conclusions on GH, so further research is needed to solve such problems about suitable population, starting time, dosage and course of treatment. In consideration of potential risks, patients receiving treatment with assisted reproductive technology should conduct individualized comprehensive evaluation before using GH, and then carefully formulate treatment plans for patients.LH and LZ determine the topic and write the manuscript, HT and XG retrieve literatures and analyze data. All authors contributed to the article and approved the submitted version.


Non-alcoholic fatty liver disease (NAFLD) is defined as a combination of a group of progressive diseases, presenting different structural features of the liver at different stages of the disease. According to epidemiological surveys, as living standards improve, the global prevalence of NAFLD increases. Acute kidney injury (AKI) is a class of clinical conditions characterized by a rapid decline in kidney function. NAFLD and AKI, as major public health diseases with high prevalence and mortality, respectively, worldwide, place a heavy burden on societal healthcare systems. Clinical observations of patients with NAFLD with AKI suggest a possible association between the two diseases. However, little is known about the pathogenic mechanisms linking NAFLD and AKI, and the combination of the diseases is poorly treated. Previous studies have revealed that liver-derived factors are transported to distal organs via circulation, such as the kidney, where they elicit specific effects. Of note, while NAFLD affects the expression of many hepatic factors, studies on the mechanisms whereby NAFLD mediates the generation of hepatic factors that lead to AKI are lacking. Considering the unique positioning of hepatic factors in coordinating systemic energy metabolism and maintaining energy homeostasis, we hypothesize that the effects of NAFLD are not only limited to the structural and functional changes in the liver but may also involve the entire body via the hepatic factors, e.g., playing an important role in the development of AKI. This raises the question of whether analogs of beneficial hepatic factors or inhibitors of detrimental hepatic factors could be used as a treatment for NAFLD-mediated and hepatic factor-driven AKI or other metabolic disorders. Accordingly, in this review, we describe the systemic effects of several types of hepatic factors, with a particular focus on the possible link between hepatic factors whose expression is altered under NAFLD and AKI. We also summarize the role of some key hepatic factors in metabolic control mechanisms and discuss their possible use as a preventive treatment for the progression of metabolic diseases. Together, the liver and kidney are extremely important for the maintenance of systemic homeostasis in the organism. These organs interact under both physiological and pathological conditions, and it is widely accepted that impairment of the function of one organ exerts pathological effects on the other . A varieThe liver is an important endocrine organ that secretes hepatic factors. Its unique structure and extensive blood perfusion allow it to send molecular signals to, and thus to communicate with, distant tissues or organs via the blood flow. Dysregulation of the pathway of inter-organ communication centered on the liver may lead to improper regulation of energy homeostasis and, eventually, to metabolic dysfunction-like diseases, which provides some theoretical support to explain the high incidence of CKD and AKI under NAFLD. Therefore, deciphering the mechanisms whereby hepatic factors are expressed and interact with distal tissues or organs is crucial for the prevention and treatment of metabolic diseases. In the current review, we briefly characterize NAFLD and AKI and crosstalk between them, focusing on hepatic factors affected by NAFLD that may link NAFLD with AKI. We also highlight the prospective use of hepatic factors as possible targets for developing preventive treatment for the progression of metabolic diseases.NAFLD presents with major lipid accumulation and steatosis of the liver and encompasses nonalcoholic fatty liver, nonalcoholic steatohepatitis (NASH), and cirrhosis . The incThe pathogenesis of NAFLD stems from a wide range of sources. Traditionally, high food intake, poor dietary habits, metabolic dysfunction, oxidative stress, and genetic factors have been viewed as pathophysiological mechanisms of NAFLD. In recent years, studies focusing on the intestinal flora revealed that, surprisingly, alterations along the gut–liver axis may also be an important factor in the development of NAFLD . FibrosiInflammation and insulin resistance (IR) play an important role in NAFLD. The effects of NAFLD-mediated metabolic syndrome (MetS) characterized by cytokine storm and IR are not limited to the liver. However, under pathological conditions, the circulating hepatic factors potentiate the systemic impact of NAFLD . HepaticAKI is an acute and rapidly injurious disease. It leads to a sudden decline and loss of kidney function, as evidenced by a sudden decrease in the glomerular filtration rate (GFR), an increase in serum creatinine (Scr) levels, and a disruption of body homeostasis . AKI serAKI can be triggered by a variety of factors, such as infection, hypovolemic shock, sepsis, nephrotoxic drugs, or surgery, and the disease outcome is primarily related to the severity and duration of the trigger . DespiteBecause of the unique timing of AKI, early detection is crucial. However, the lack of a single biomarker recognized as an early marker of renal impairment contributes to the difficulties in the early diagnosis of AKI. Based on the traditional use of KIM-1 and matrix metalloproteinase tissue inhibitory factor (TIMP)-1 as detectors of kidney injury, some new indicators, such as insulin-like growth factor-binding protein (IGFBP) 7, are continuously discovered to facilitate early identification of AKI . Some inOrgan cross-talk is a relatively novel concept describing organ-to-organ and organ-to-tissue signaling. Dysregulation of the cross-talk can disrupt systemic homeostasis, which may induce disease . The livThe liver, as the main secretory organ, has long been the focus of extensive research. It releases organ-specific cytokines, also known as hepatic factors or hepatokines, that have autocrine, paracrine, and endocrine functions . These mHepatic factors play an irreplaceable role in coordinating systemic energy metabolism, and the liver adjusts secretion in response to changes in the body, as evidenced, e.g., by a differential expression of hepatic factors in patients with T2DM and NAFLD compared with that in healthy individuals. Because of its powerful secretory function, the liver plays an important role in maintaining systemic homeostasis, and the dysregulation of hepatic secretion may lead to improper regulation of energy homeostasis and, eventually, to metabolic dysfunction. Unfortunately, little is known about the regulatory mechanisms of hepatic factor involvement in the MetS. Hence, revealing the liver-centered inter-organ interaction mechanisms is a formidable research challenge for the future. Below, we summarize the mechanisms that link liver and kidney to determine predisposition to AKI in patients with NAFLD.ANGPTLs (ANGPTL1 to ANGPTL8) are circulating hepatic factors. Their structure is similar to that of members of the angiopoietin family of proteins . ANGPTLsANGPTL1, a vasopressor, was the first protein from the ANGPTL family to be identified. Initially, it was overwhelmingly studied in the context of the cardiovascular system, because of its expression mainly in vascularized tissues . ANGPTL1ANGPTL2 has been detected in the adipose tissue, kidney, and skeletal muscle. Fibrosis in tissues, such as the liver and kidney, is closely related to chronic inflammation, and ANGPTL2 may play an important role in the fibrotic response of organs. Additionally, ANGPTL2 expression inhibits the secretion of inflammatory cytokines by renal tissues, which in turn inhibits renal autophagy and regulates renal fibroblast activation .ANGPTL3 is a specific secretory factor expressed and secreted mainly by hepatocytes, although is expressed both in the liver and kidney. It is a polypeptide of 460 amino acids with a characteristic angiopoietin structure . ANGPTL3ANGPTL4 is mainly secreted into the circulation by white and brown adipose tissue and liver tissue . SimilarANGPTL5 is mainly expressed in adipose tissue. According to published studies, it can regulate triglyceride metabolism to alleviate the MetS caused by energy imbalance, a finding further supported by the increase in triglyceride levels in obesity and diabetes. In a recent study on exercise and circulating ANGPTL5 levels, the relationship between ANGPTL5 and prevalent cardiovascular disease risk factors was investigated by comparing circulating ANGPTL5 levels in obese normal-weight adolescents. Elevated levels of ANGPTL5 were detected in obese adolescents and were associated with cardiovascular disease risk factors, high-sensitivity C-reactive protein, and oxidized low-density lipoprotein .ANGPTL6 is secreted into the circulation mainly by the liver. It may play an important role in human metabolism as such, as it is important for the maintenance of glucose homeostasis. It has been reported that targeted activation of ANGPTL6 leads to increased insulin sensitivity, increased energy expenditure, and prevention of diseases related to IR, e.g., a reduced risk of developing diabetes . In anotANGPTL8 is mainly secreted by the liver and often acts as a physiological inhibitor of LPL, a key enzyme of plasma triglyceride metabolism. Hence, ANGPTL8 plays a key role in lipoprotein and triglyceride metabolism . Of noteFetuin-A and fetuin-B are glycoproteins that share 22% sequence similarity and belong to the same cystatin superfamily of proteins. Fetuin-A is released mainly by the liver, and the first liver-derived protein that has been shown to be associated with metabolic diseases . It is cFetuin-B expression is increased in the liver of patients on a high-fat diet. The expression of both fetuin-B and fetuin-A is altered in the development of fatty liver compared to normal subjects. However, unlike fetuin-A, fetuin-B is not involved in pro-inflammatory signaling and macrophage activation induced by NAFLD. Instead, it may potentiate steatosis and induce the development of IR. According to a recent study, silencing of fetuin-B gene improves glucose tolerance in obese mice without altering the body weight, suggesting the specificity of this regulation.There are two pathways to increasing insulin levels: increasing the amount of insulin produced and increasing the efficiency of glucose utilization. Instead of acting via the classical mechanism of insulin dependence to regulate blood glucose levels, fetuin-B may act via another insulin-independent mechanism, e.g., involving efficient glucose utilization . The exaDespite their similarity, fetuin-A and fetuin-B play different roles in the pathophysiology of fatty liver. The expression of fetuin-A and fetuin-B is both upregulated in the presence of hepatic steatosis in human, but their regulation of glucose homeostasis is different fetuin-A alters insulin signaling, while the fetuin-B mechanism may be related to glucose utilization . ConsideFGF are a class of proteins secreted primarily by the liver and involved in multiple biological functions in vivo . They plFGF1 knockout mice that consumed high-fat foods, suggesting that FGF1 may play a regulatory role in nutritional homeostasis [FGF1 has been used in recent studies as one of the potential safe candidate targets for restoring normoglycemia in T2DM . Pronouneostasis .Elevated FGF2 expression was detected in the tissues of obese patients, and significantly elevated protein levels in the serum of patients with cirrhosis and HCC .FGF19 is involved in the regulation of lipid metabolism and glucose homeostasis . A signiFGF21 is produced by the liver. It enters the bloodstream and is an important regulatory molecule controlling hepatic lipid metabolism and glucose metabolism . ElevateHepcidin (HPS) is a hepatocyte-derived fibrinogen-associated protein, and a novel hepatic factor that causes accumulation and degeneration of hepatic fat, and ultimately IR. HPS is a specific mitogenic activator of hepatocytes, and its overexpression in HCC cells inhibits cell growth . HPS is RBP4 is derived from adipose tissue, transports retinol (vitamin A) into the serum, and may act as a mediator between obesity and IR . DiffereAs stated in the definition, IGF is structurally and functionally very similar to insulin, and there is evidence that altered IGF signaling may be potentially relevant to HCC progression . IGF-1 iIGFBPs regulate circulating IGF levels by binding to IGF, thereby keeping it in circulation for transport to peripheral tissues. IGFBPs also play an IGF-independent role. For example, IGFBP7 inhibits the expression of proteins associated with the activation of IGF signaling by binding to IGF-1 receptor and acts as a tumor suppressor, and IGFBP7 deficiency may promote HCC . FurtherIGFBP7 is strongly associated with liver disease. Of note, according to several studies, it is abundantly expressed in the kidney, with differential expression of IGFBP7 observed in the urine of patients with AKI. In addition, we found that IGFBP7 has unique advantages as an early indicator of AKI, and its development, as early detection of AKI has a great potential for application translation. However, the appropriate IGFBP7 threshold has not yet been determined, resulting in a lack of universal acceptance of the definition of AKI in terms of IGFBP7 levels. Meanwhile, while plasma IGFBP7 concentrations can be used to predict renal and cardiac events in participants with T2DM and high cardiovascular risk, more research is needed on the association between circulating IGFBP7 and the progression of diabetic nephropathy ,80. WhilSeP is a secreted protein of hepatic origin that distributes selenium to the rest of the body via circulation to maintain homeostasis . The maiNAFLD is often considered a progressive disease and involves a range of serious complications, such as lipid accumulation, steatosis, inflammation, fibrosis, cirrhosis, and HCC . The proThe MetS is widely believed to be associated with unhealthy lifestyle habits, such as excessive nutritional intake, inactivity, and resulting obesity . TraditiMany current studies define being overweight and obese based on the body mass index . ObesityAKI is a global public health problem. Various risk factors are associated with AKI, such as surgical or traumatic infection, hypovolemic shock due to bleeding, sepsis, drug intake, traumatic surgery, oxidative stress, and abnormal apoptosis . FurtherNAFLD alters the hepatic secretion of many proteins, and a major proportion of these proteins affect the insulin response. Further, the liver can interfere with the physiological state of some extrahepatic tissues, such as skeletal muscle and fat, through inflammation, fatty acid oxidation, and other pathways that together contribute to the IR status of the body. The liver can influence insulin secretion by the pancreas not only via the extrahepatic factors described above, but also by independently influencing glucose utilization by peripheral tissues via protein secretion .The liver acts as an endocrine organ that secretes hepatic factors. Because of its unique structure and ability to regulate blood flow, the liver can send molecular signals to and interact with distant tissues via circulation. Dysregulation of inter-organ pathways centered on the liver may lead to misregulation of energy homeostasis and, eventually, to metabolic dysfunction or new diseases. Explaining the mechanisms that regulate the expression of hepatic factors and their linkage to distant tissues or organs in NAFLD is essential for understanding inter-organ interactions and developing therapeutic strategies to treat metabolic dysfunction . NAFLD iThe liver receives approximately a quarter of the cardiac output, which, because of the high level of blood perfusion, allows the redistribution of hepatic factors to other tissues. Because of the unique structure and regulation of blood flow in the liver, proteins secreted by hepatocytes and non-parenchymal cells within the liver concentrate in the hepatic sinusoids, and then circulate to the heart through the central vein to the inferior vena cava, from which they are redistributed to peripheral tissues. NAFLD alters the expression of a variety of hepatic proteins and thus affects peripheral metabolism . AKI in Studies have shown that various hepatic factors, such as ANGPTL4, ANGPTL6, FGF21 and IGF-1, secreted by the liver are important for alleviating metabolic dysfunction and may have positive implications for the prevention of AKI. These hepatic factors are differentially expressed in the liver with steatosis, which may lead to a disruption of energy homeostasis and, ultimately, to metabolic dysfunction, such as AKI. The current treatment of AKI depends on its cause: renal volume resuscitation is used for pre-renal AKI, intravenous albumin, vasoconstrictors for hepatorenal syndrome AKI, and supportive therapy for acute tubular necrosis .Based on the observations that the expression of hepatic factors changes in disease and that hepatic factors regulate metabolic phenotypes of distal tissues or organs, we propose that analogs of beneficial hepatic factor or inhibitors of deleterious hepatic factors could be developed in the future as a treatment for AKI or other metabolic diseases that occur during NAFLD.If the regulation of hepatic factor expression is important for AKI prevention, then the use of early diagnostic biomarkers for AKI is an essential test of therapeutic efficacy. These biomarkers indicate a strong possibility of AKI before it occurs and accurately reflect the progression of renal damage in AKI.Because of the slow pace of development of breakthrough biomarkers for the early diagnosis of AKI, currently, clinicians still grade AKI based on Scr levels and urine volume. However, the lack of sensitivity of these two to kidney injury and the severe lag between them render them inefficient for diagnosis ,21. In 2A few markers of kidney injury have been established, such as KIM-1, NGAL, TIMP-2, and IGFBP7. KIM-1 is one of the markers of early kidney injury. This protein can cross the cell membrane. When renal tubular cells are injured by ischemia, the expression of KIM-1 increases, and the protein rapidly enters the tubular lumen from the extracellular fraction to protect the injured kidney . ElevateOverall, the above proteins are more highly expressed in patients with AKI than in those without AKI, and their parallelism with the traditional markers Scr and urea nitrogen supports their credibility as early diagnostic biomarkers for AKI. However, some challenges remain for biomarker selection, and the complexity of AKI causation in the clinical setting and differential marker selections lead to the development of different detection methods. A combination of multiple markers may be a good solution for the time being to improve diagnostic accuracy, but more research is needed to address the problem of early diagnosis of AKI.As the liver and kidney are both extremely important for systemic homeostasis, impairment of the function of one organ can induce pathogenesis affecting the other organ. Newer studies and clinical observations have revealed several biochemical and molecular pathways that may implicate the liver in the development of AKI, including alteration of liver enzyme profiles, oxidative stress, activation of inflammation, and apoptosis. The molecular interactions linking the liver to the kidney that are not organ-based are supported by research findings. Hepatic factors that alleviate the metabolic dysfunction upon hepatic steatosis include ANGPTL4, ANGPTL6, FGF21, IGF-1, etc. These proteins regulate adipocyte activation to increase energy expenditure, increase insulin sensitivity and glucose uptake by the body, reduce plasma triglyceride levels, and regulate cholesterol homeostasis. In other words, they reduce the energy overload of the body to reduce the possibility of induction of other metabolic diseases.The question of how to maintain systemic homeostasis in the event of NAFLD can be approached in two major ways. We can control the development of metabolic disease by controlling the abnormally elevated levels of liver proteins during the disease, including some ANGPTL family proteins, fetuin-A, heparin, etc. This would control the development of metabolic disease by improving insulin sensitivity and maintaining lipid homeostasis to suppress systemic inflammation and IR. Dysfunction of organs other than the kidney is likely a non-negligible factor in the development of AKI and its poor prognosis, which explains why AKI often occurs in combination with other serious illnesses. Clinical case data suggest that major organs, such as the lung, heart, brain, and liver, are potentially involved in a cross-talk with the kidneys. Hence, their dysfunction may increase the risk of AKI. During the onset of AKI, the interaction of the other organs with the kidney is perturbed, which results in abnormal immune cell activation, massive increase in inflammatory factors, mitochondrial dysfunction, and abnormal apoptosis of a large number of functional kidney cells. Interestingly, these are also potential mechanisms by which AKI affects the function of organs other than the kidney.We hypothesize that the association between NAFLD-mediated hepatic factors and AKI is mainly two-fold: First, NAFLD, the expression of a variety of hepatic factors that are beneficial to the systemic metabolism is altered, as a result of dysregulation of immunity, inflammation, and oxidative stress, all of which are closely related to the occurrence of AKI. Second, since the liver receives a major portion of the total cardiac blood output, it can distribute hepatic factors throughout the body via the circulation with the possibility of inter-organ interaction to regulate metabolic phenotypes. This suggests a link between hepatic factors and AKI in patients with NAFLD, involving IR, lipotoxicity, oxidative stress, and inflammatory factors, although the specific pathways and mechanisms should be supported by further studies.In this review, we first summarized the role of the major hepatic factors, then explored the connection between NAFLD and AKI based on their mechanisms of action, and finally proposed flexible regulation of the expression of circulating hepatic factors perturbed in disease to control metabolic disease as a treatment for NAFLD. In the foreseeable future, circulating hepatic factors as a means to regulate metabolic homeostasis will show great application prospects.


The intrinsic architecture and complexity of the brain restricts the capacity of therapeutic molecules to reach their potential targets, thereby limiting therapeutic possibilities concerning neurological ailments and brain malignancy. As conventional models fail to recapitulate the complexity of the brain, progress in the field of microfluidics has facilitated the development of advanced in vitro platforms that could imitate the in vivo microenvironments and pathological features of the blood–brain barrier (BBB). It is highly desirous that developed in vitro BBB-on-chip models serve as a platform to investigate cancer metastasis of the brain along with the possibility of efficiently screening chemotherapeutic agents against brain malignancies. In order to improve the proficiency of BBB-on-chip models, hydrogels have been widely explored due to their unique physical and chemical properties, which mimic the three-dimensional (3D) micro architecture of tissues. Hydrogel-based BBB-on-chip models serves as a stage which is conducive for cell growth and allows the exchange of gases and nutrients and the removal of metabolic wastes between cells and the cell/extra cellular matrix (ECM) interface. Here, we present recent advancements in BBB-on-chip models targeting brain malignancies and examine the utility of hydrogel-based BBB models that could further strengthen the future application of microfluidic devices in oncology research. The brain is perhaps the most important and metabolically active organ in the body and is known for its dedicated complex structural and functional hierarchy . AlthougThe BBB plays a crucial role in maintaining the internal milieu inside the brain by supervising the constitution of cerebral extracellular fluid (ECF) and imparting protection against the invasion of harmful agents . The essAlthough the BBB represents an essential barricade for the purpose of brain protection, it also serves as a barrier to therapeutic interventions during brain tumor progression, and because of this a number of chemotherapeutic drugs such as vincristine, paclitaxel, etc., are unable to reach the brain . Hence, Conventional two-dimensional (2D) in vitro models such as the Transwell system have extensively been used for studying the basic features of the BBB, such as barrier permeability and transepithelial/transendothelial electrical resistance (TEER) ,16. HoweIn recent years, many researchers have compiled experimental outcomes in this field with outstanding synopses. The review by Augustine et al. presents a design concept for bioengineered microfluidic-based BBB models in the field of oncology . MoreoveComplementing the aforementioned reviews, in this review, the salient features and physiology of the BBB and its dysfunction/dysregulation upon tumor invasion is discussed. Further, the review aims to explore the salient features of hydrogels that can be explored to recapitulate the architecture of the BBB and its microenvironment. The review also highlights the practicalities and attributes of various microfluidic-based BBB designs and their applicability for oncology research (brain primary tumor and metastasis). In this review, we discuss the available hydrogel-based  microfluidic BBB models and their salient features. Finally, we present some emerging challenges that accompany hydrogel-based microfluidic BBB models along with the future prospects of this fascinating area. Due to the emergent status of the field of hydrogel-based microfluidic BBB models dedicated to oncology research, application-oriented literature reported over the last five years was the primary focus in this review. The overall aim of this review was to offer readers a better understanding on hydrogel-based BBB microfluidic devices for brain malignancies.The BBB, located in the brain capillaries, plays a strategic role in maintaining the homeostasis of the CNS and protecting it from detrimental factors and pathogens present in the blood. Early electron microscopic studies on the BBB claimed it to be mainly composed of specialized ECs lining the blood vessels that stream through the brain , represeDue to the presence of TJs within the brain capillary endothelium, intercellular pores are absent to prevent brain endothelium with minimal fluid-phase pinocytosis . The preThe brain ECs are further supported by a discontinuous layer of perivascular cells, mainly PCs and ACs. These perivascular cells perform a significant role in the formation and functioning of the BBB . The proThe infiltration of cells into the CNS is highly restricted by the BBB, but preferential metastasis of some cancer to the brain is very surprising; hence, it would not be an overstatement to link the role of the BBB to the support of metastasis formation. As metastatic cells relish protection against immune scrutiny, it is anticipated that some releasing factors from the cellular components of the BBB may favor metastatic growth.New therapeutic interventions have augmented the treatment possibilities for cancer in most parts of the body, but the efficacy of these new clinical modalities is still unrealized in case of primary or secondary (metastatic) brain tumors . AlthougTo date, mRNA for nearly 15 drug transporters have been identified in brain capillaries, which include but is not limited to p-glycoprotein (Pgp), multidrug resistance-associated protein (MRP), multidrug-resistance protein, organic anion transporting polypeptide (OATP), and organic anion transporter (OAT) . In contChanges in the structural architecture of the BBB upon tumor invasion are influenced by the tumor stage, volume, type, and location . The graAlthough the intrinsic architecture of the BTB is disrupted inside the tumor, there are reports of BTBs retaining intact features in some specific areas in a tumor ,70. ThesDisruption or alteration in BBB architecture is associated with many pathological conditions, but the severity of its disruption is mainly connected to gliomas . Hence, Although establishing a BBB model is a challenging task, a successful model should meet specific requirements and parameters to guarantee data consistency, reproducibility, and precise correspondence with the complex nature of the BBB. Any established model of the BBB should accurately mimic the BBB architecture, including ECs, Acs, PCs with luminal and abluminal sides, and articulate TJs and adherence junctions (AJs) in the endothelium ,73. The While recapitulating the anatomy and physiology of the BBB, genetic heterogeneity could be a vital factor. Clinical translations of many drugs for human use are unlikely, even they demonstrate commendable therapeutic effects during animal testing. This could be due to the difference in the genetic constituents of animal models and humans, which restricts the complete reproduction of an organoid/tissue. Hence, human-originated cells would definitely have an edge in the design of BBB models. Concerning the permeability attributes, a model should have selective permeability for different therapeutic molecules based on their molecular weights and inherent lipophilic nature. Moreover, the model should respond to change in terms of the permeability of the barrier upon interaction with external agents (enhancers) and encounters with pathological conditions such as diabetes and hypertension. Preferably, the established model should allow for the real time assessment of different cellular level interactions, permeability, and imaging and should be dynamic in nature. Overall, apart from the aforesaid benchmarks, the model should be straightforward and effective in terms of cost, reliable, easy to handle, reproducible, and experiment friendly.Establishing a realistic BBB model could have widespread applicability in studying the transportation dynamics across BBBs under normal circumstances and diseased condition and aid in the development of efficient therapeutic interventions with passable distribution in the brain. Scientific communities have invested a lot of effort in the development of in vitro BBB models to avoid the difficulties faced in the clinical translation of results obtained from animal models. In this regard, several 2-dimensional (2D) in vitro models have been established with mono/co/tri culturing of human derived cells (ECs/PCs/ACs) in order to imitate the transportation pattern of different molecules across BBB endothelium ,75,76,77The term microfluidics is defined as the study of systems comprising miniature quantity of fluids at the submilliliter dimension. Microfluidic technology involves the designing of miniature systems and studies involving physics, performance, and control of fluids, confined in small channels ,82. The In 1990, Manz et al. created the term “miniaturized total chemical analysis systems (µTAS)” to describe small-volume related reactions . SubsequThe first practical model of OCC-based microfluidic chips was fabricated in 2010, when Donald E. Ingber’s research team at the Wyss Institute at Harvard University first demonstrated a practical model of a lung-on-a-chip . SubsequIn order to imitate the anatomical and physiological aspects of the BBB, an ideal in vitro BBB model should able to address some key attributes of in vivo BBBs which include: intercellular interactions, the vessel-like structural architecture of ECs resembling 3D vessels, flow dynamics provoked by shear stress on ECs, and the selective permeable basal membrane (BM) . FurtherMicrofluidic platforms evolved from the orthodox Transwell design, which comprises of porous membranes placed between upper and lower channels to create a sandwich-like assembly. Here, the two chambers define neural and vascular channels separated by a porous membrane. The complete system represents vascular channels and the complete architecture of an intact in vivo BBB . In thisIn another study, Booth et al. designed a multi-layered microfluidic device comprised of two vertical microchannels separated by porous polycarbonate membrane along with multiple embedded electrodes . In ordeMoreover, the examination of cell behavior still remains a challenge, which could be confronted through the use of parallel designs in which the culture chambers are arranged horizontally and separated with polydimethylsiloxane (PDMS) membrane. The advantage of parallel designs is their utility for high resolution image capture due to improved observations of cell behavior . The usePDMS-based microfluidic BBB models are generally fabricated with rectangular cross-sections in the microchannels, which may result in non-uniform shear stress and profiles. These uneven flow dynamics may cause divergences in the behavior and morphological aspect of the seeded ECM along the channel . To overAs an advanced technology, microfluidics-based devices have been able to effectively recapitulate complex and 3D microenvironments of tissues with suitable regulations. Thus, as an alternative, microfluidic devices have been successful in overcoming and limiting the use of animal models for studying the physiology and function of tissues/organs pre/post pathological conditions. This reputation has been propelled due to the incredible progress seen in microfabrication and microfluidic techniques, which have been influenced by salient BBB-specific features which need to be examined for model integrity. A summary of the existing BBB-on-chip models for oncology research is presented in Hydrogels are a category of 3D crosslinked polymeric network structures capable of imbibing a large amount of water. Owing to their tunable properties and versatile fabrication methods, hydrogels have been applied in numerous biomedical applications ranging from drug delivery to tissue engineering and regenerative medicine . In ordeWhen selecting hydrogels as an ECM-imitating material for microfluidic-based BBB models, the innate properties of hydrogels are very important. The mechanical features of the ECM memetic hydrogel material, such as its stiffness, elasticity, stress, strain, and porosity, play a significant role in cell adherence, migration, and cytoskeletal assembly. In general, rigid ECM materials may possess a higher stiffness than that of brain microvessels ,118. TheAnother important aspect of hydrogels that needs to be considered when selected them in the design of a microfluidic-based model is their degradation properties. The degradation of hydrogels over time can lead to alterations in their mechanics and swelling properties, which may affect cellular activities such as motility, migration, and traction force generation ,126. WhiHydrogel-based 3D BBB-on-chip models mainly depend on the injection of hydrogels into a central compartment which is surrounded by two peripheral fluidic channels. In these external channels, ECs are seeded to establish adherence with the hydrogel in order to stimulate the vascularization of the matrix ,132. TheMicrofluidic BBB models are micrometre-sized mechanical channels comprised of 3D arrangements of multiple cell types and a hydrogel matrix to mimic BBB complexity. These platforms offer more resemblance to the brain microvasculature and its physical and biological microenvironments than the traditional in vitro BBB platform. The model is comprised of four main components, including a hydrogel 3D matrix, a continuous supply of fluid with shear stress and controlled osmotic pressure, a brain tissue chamber, and an array of biosensors for the long-term monitoring of the BBB microenvironment . The hydThe importance of hydrogel matrices in microfluidic models has grown substantially in recent decades because of their capability to form complex networks for providing a microenvironment for cellular growth and their flexibility to modulate as per the application requirements ,137. TheGlioblastoma (GBM) is a highly aggressive primary brain tumor, with a median survival of <15 months . DespitePseudopalisade, a hypercellular zone that typically surrounds necrotic tissue is a characteristic feature of GBM. A custom-designed microfluidic device was developed by Ayuso et al. to imitate the dynamics of pseudopalisade formation in GBM using U-251 MG cells embedded in a collagen hydrogel matrix . In addiIn the field of brain oncology, tumor metastasis is a serious phenomenon that needs considerable attention. An innovative BBB model for metastatic brain tumors could improve our understanding of the condition and help design new treatment strategies. A new dynamic 3D microfluidic system was developed by Xu et al. to replicate the key structural, functional, and mechanical properties of the blood–brain barrier . The micRecently, Hajal et al.  created In an effort to recreate a more physiologically relatable BBB microenvironment with other brain cells types , various strategies have been explored to introduce ECM-mimicking components. The mechanical attributes and the interstitial flow in the cellular microenvironment influences the propagation of ECs. Also, a high concentration of the selected hydrogel material at the interface ensures the quiescent stage of the endothelium. An ideal hydrogel-based 3D microdevice should ensure an enhanced rate of recovery for a damaged BBB. Efforts are being made to further investigate the use of natural hydrogels as compelling candidates for fabricating 3D BBB models. Also, hydrogel-based BBB microfluidic models could be explored to understand the multicellular interactions across the BBB during the therapeutic intervention process.Synthetic hydrogels are designed to adapt to structural changes in response to various chemical and physical variations. A key aspect of synthetic hydrogels is that they acquire tunable properties along with facile fabrication routes with functional outcomes. Commonly used polymers, as key components for the formation of hydrogels, include polyethylene glycol (PEG), polycarbonate urethane (PU), and poly(epsilon-caprolactone) (PCL) . When usIn this regard, a novel 3D brain cancer chip model with integrated microfluidic channels was developed using PEG diacrylate (PEGDA) hydrogel and GBM cells (U87) . To studTo further improve the complexity in terms of the BBB, the cells in the microfluidic system were replaced by patient tissue-derived 3D spheroids. These developed spheroid tissues recapitulate the pathological characteristics and complex ecology of native tumors, meaning that the model can serve as a personalized monitoring device which could help design appropriate cancer treatment for individual patients. The model mimics the biochemical and biophysical properties of the native GBM using a 3D bioprinting process to create a cancer analog on a chip. The device combines a compartmentalized cancer–stroma structure, an oxygen gradient-generating system, and a brain decellularized ECM . The modThe complicated structure and physiological attributes of the brain have always posed challenges when it comes to the transportation of chemotherapeutic molecules across the BBB. The high attrition rate of therapeutic molecules and their constantly mounting mortality rate indicates the ineffectiveness of existing preclinical models in delivering clinically relevant assessments. Though the use of animal models has given some edge, the existence of species-specific cellular interactions and the difficulty of transferring their clinical relevance to humans have undermined their legitimacy in forecasting precise outcomes in clinical trials. Technological progress in science and medicine has given rise to many in vitro BBB models to investigate different neurological ailments, including malignancies, but these lack dynamic blood flow conditions. Microfluidic systems and organ-on-chip technology have been able to recapitulate the 3D architect of complex tissues and organs, thereby offering new insights into complex cellular behavior and functions. There has been an expeditious advancement in the field of microfluidics and their use has been proven to be practical in numerous biomedical applications. The efficiency of existing BBB-on-a-chip models can further be improved through the use of hydrogels that mimic the 3D micro architecture of tissues. Hydrogel-based BBB-on-a-chip models can recapitulate a 3D microenvironment conducive for cell growth and allow for the exchange of gases and nutrients and the removal of metabolic wastes between cells and the cell/ECM interface, and thus are able to regulating ECM behavior. In addition, they enable the simultaneous assessment of drug penetration across the BBB, the efficacy of therapeutic molecules on tumor cells, and the evaluation of the toxicity profile of drugs for a normal cell in the case of an intact BBB and within the tumor-invaded cells in the case of a disintegrated BBB. Here, we have provided a comprehensive review of currently available BBB-on-chip models, focusing on the device design type, incubated cell types, and salient features. These models have proven or been proposed to have direct involvement in brain primary and secondary malignancies. We further discussed the design concept of available hydrogel-  based in vitro microfluidic BBB models.However, different cell types respond differently when grown over a microfluidic chip. Various complex device designs and a plethora of cell types make it very difficult to generalize any concept. Further, suboptimal cell growth in different chambers of the microfluidic chip can also be an issue that needs to be taken care of when making an overall assessment of the obtained outcomes. As most of the generated cell-specific information is optimized, analyzed, and evaluated on glass or polystyrene based culture plates, most microfluidic chips are fabricated using PDMS, and a straightforward comparison on the cellular behavior on these discrete substrates is very difficult. This increases the time and utilization of resources involved in regenerating and evaluating findings. Another challenge that needs to be adequately handled is the maintenance of sterility conditions for the designed organ-on-a-chip. This ensures the consistency and reliability of the obtained results. Furthermore, as microfluidic devices handle a very minute volume of samples, absolute care is required during the execution and handling process.Organ-on-a-chip technology demands a highly interdisciplinary approach and a collective effort from biologists, biochemists, chemists, material sciences, and engineers. To see through the production of microfluidic devices from laboratory table to clinical platforms, their cost effectiveness in terms of mass production, their reliability, and the reproducibility of the generated data are all crucial aspects. Effort needs to be made to pursue and fabricate novel materials that can be used to provide long term culture support. The subsequent application of hydrogels as the materials of choice and the recognition of in vitro hydrogel-based BBB-on-chip models by regulatory authorities and industries could lead to the enhanced throughput screening of chemotherapeutic agents and assist in further gaining insight into brain malignancies. This will also aid in the diminution of the use of animal models frequently used in BBB-related research.


Osteonecrosis of the jaw resulting from treatment with antiresorptive agents, such as bisphosphonates and denosumab, is widely recognized as medication-related osteonecrosis of the jaw (MRONJ). However, to the best of our knowledge, there are no reports of medication-related osteonecrosis of the upper jaw extending to the zygomatic bone.An 81-year-old woman treated with denosumab for multiple lung cancer bone metastases presented to the authors' hospital with a swelling in the upper jaw. Computed tomography showed osteolysis, periosteal reaction of the maxillary bone, maxillary sinusitis, and osteosclerosis of the zygomatic bone. The patient underwent conservative treatment; however, osteosclerosis of the zygomatic bone progressed to osteolysis.If the maxillary MRONJ extends to the surrounding bony structures, such as the orbit and skull base, serious complications may occur.It is important to detect early signs of maxillary MRONJ, before it involves the surrounding bones. •Treatment with antiresorptive agents may cause osteonecrosis of the jaw.•Extension of maxillary MRONJ to the zygomatic bone has not been reported.•Extension of maxillary MRONJ to the adjacent bones may cause serious complications.•Conservative treatment is the first-line therapy for MRONJ.•Surgery is recommended in case of poor treatment outcomes. Eight months after surgery, CT showed progression of osteosclerosis of the zygomatic bone to osteolysis  . Of thesActinomycesThe organisms isolated from MRONJ are usually bacteria indigenous to the oral cavity, such as In conclusion, if maxillary MRONJ extends to the surrounding bones complications may arise and treatment may become challenging. Therefore, it is important to detect early signs of maxillary MRONJ.4It is important to detect early signs of maxillary MRONJ, before it involves the surrounding bones.Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.Ethical Approval was waived by the authors institution.None.All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Sakiko Soutome, Saki Hayashida, Souichi Yanamoto, Kota Morishita, and Masahiro Umeda. The first draft of the manuscript was written by Mitsunobu Otsuru, and all authors commented on the previous versions of the manuscript. All authors read and approved the final manuscript.Mitsunobu Otsuru.None.None.


Glaucoma is the first major category of irreversible blinding eye illnesses worldwide. Its leading cause is the death of retinal ganglion cells and their axons, which results in the loss of vision. Research indicates that glaucoma affects the optic nerve and the whole visual pathway. It also reveals that degenerative lesions caused by glaucoma can be found outside the visual pathway. Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that can investigate the complete visual system, including alterations in the optic nerve, optic chiasm, optic tract, lateral geniculate nuclear, and optic radiation. In order to provide a more solid foundation for the degenerative characteristics of glaucoma, this paper will discuss the standard diagnostic techniques for glaucoma through a review of the literature, describe the use of DTI technology in glaucoma in humans and animal models, and introduce these techniques. With the advancement of DTI technology and its coupling with artificial intelligence, DTI represents a potential future for MRI technology in glaucoma research. Glaucoma is a diverse group of diseases characterized by damage to the retinal ganglion cells (RGC) and their axons, the retinal nerve fiber layer (RNFL), which leads to progressive vision loss . If leftDiffusion tensor imaging (DTI) is now the most prevalent method for investigating WM degeneration in glaucoma patients . In addiRoutinely used methods for glaucoma evaluation include gonioscopy, IOP measurement, corneal thickness measurement, fundus photography, VF inspection, and optical coherence tomography (OCT) . MoreoveThe term “visual field” refers to the area the human eye can perceive, and the “VF examination” primarily refers to the perimeter measuring this region. VF examination is a subjective test used to diagnose glaucomatous damage and quantify the degree and severity of visual impairment in glaucoma patients . The autOptical coherence tomography is a non-invasive imaging technology that permits the quantitative measurement of changes in the ON, RGC axon, and RGC body layer, RNFL . Since iOptical coherence tomography angiography is a non-invasive, dye-free imaging technique that can measure the retina, optic papilla, and choroidal blood vessels in qualitative and quantitative ways. OCTA can provide information on the extent of perfusion damage at various depths in the retina and choroid. Because advanced glaucoma has a lower vascular density , OCTA caConventional glaucoma diagnostic technologies, including fundus photography, OCT, OCTA, and VF, focus exclusively on the retinal region and disregard information regarding the WM of the brain, which transmits and systematically processes vision. The visual pathway consists mainly of the WM of the brain, and DTI is the advanced imaging technology currently available for evaluating the WM of the brain ; consequDiffusion-weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique used to assess water diffusion . Due to Changes in DTI parameters of the glaucomatous ON and beyond the ON are hot areas of current research . The folin vivo DTI was demonstrated to detect RGC axonal damage earlier than immunohistochemistry in the early stages of the disease in a mouse model of optic nerve crush-induced glaucoma (In vivo evaluations of axonal, myelin, and trans-synaptic degeneration in canine PACG can be done using DTI. Research on DTI is currently being done primarily in rat eyes, and future research on glaucoma in large animals, including dogs, pigs, and monkeys, will also be done.Diffusion tensor imaging has been examined extensively and thoroughly in glaucoma-affected animal models with altered visual pathways in experimental animal models. Numerous investigations on rat glaucoma models have documented an increase in MD and a decrease in FA of the ON and OT . Moreoveglaucoma . DTI canglaucoma . The evaGlaucoma-related modifications to DTI parameters in the visual pathway constitute a significant research focus. Multiple studies have found that glaucoma patients had lower FA and higher MD on DTI . MoreoveResearchers are particularly interested in determining whether abnormalities occur outside the visual pathway in glaucoma patients. In contrast to nature controls, NTG patients show decreased FA of OR and forceps major in the occipital lobe, according to a DTI study by As a result, we can now consider glaucoma a neurodegenerative disorder affecting the visual and extra-visual pathways owing to analyzing various types of glaucoma utilizing DTI. Additionally, DTI offers objective and quantifiable changes in the visual pathway and improves understanding of the central visual pathway’s degenerative process in human and animal glaucoma.Multiple investigations have demonstrated that as the disease progresses, FA and MD values in the ON and OR decrease and increase, respectively . In addiApplication DTI has some limitations. The human ON is small, only 3–4 mm in diameter. There may be specific areas throughout the inspection when artifacts lead to examination errors . This reMoreover, the DTI signal acquisition time is extended, which could cause motion distortions if the patient moves a lot during the examination. DTI should be enhanced and modified prior to its widespread usage in clinical glaucoma testing, which is now employed primarily for research. The accuracy and reproducibility of DTI results can be impacted by oculomotor interference, large magnetic sensitivity differences in the orbit caused by gas and bone in the sinus combined with the thin diameter of the optic nerve, encapsulation by cerebrospinal fluid in the sphincter cavity, and surrounding orbital fat . The finIn this review, we only discuss the alterations of DTI in the visual and extra-visual pathways because not only WM alterations but also gray matter alterations are present in the central visual pathways of glaucoma patients, and intracranial gray matter alterations are typically detected by functional MRI , which iThe area of glaucoma and ophthalmology, in general, is primarily image-based, and AI is situated to solve many of these problems . Deep leIn summary, DTI often showed a rise in MD and a decrease in FA, strongly linked with increasing disease severity in glaucoma patients or animal models. DTI is a promising non-invasive technique for assessing the severity and prognosis of glaucoma. As clinical and scientific uses of DTI continue to develop, practitioners in the area will engage with ophthalmologists to overcome its limits and enhance patient care.All authors contributed to draft and revise the manuscript, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work.