Functional connectivity (FC) studies showed that pharmaco-resistant mesial temporal lobe epilepsy (MTLE) affects not only the limbic system, but also several extra-limbic regions, including areas belonging to resting state networks. Less is known about FC in subjects with benign MTLE .We evaluated FC of hippocampus and amygdala in subjects with bMTLE, distinguished based on the epileptic focus lateralization. We enrolled 19 patients (10 with left and 9 with right bMTLE) and 10 age-matched healthy subjects. Connectivity was investigated at rest by using a seed-based regression analyses approach with four regions of interest . Patients were also tested with a neuropsychological battery and their scores were correlated with fMRI data.Our study documented an asymmetrical disruption of FC in bMTLE, in relation to the side of the focus. Right subjects only exhibited limited altered connections, while left subjects—who performed worse in verbal memory tests—showed a wide bilateral hypoconnectivity of hippocampus and amygdala with areas belonging to language and memory network. The strength of FC between left limbic areas and language and memory network correlated with better performances in verbal memory tests. Moreover, we observed an increased FC with areas of default mode network, more pronounced in left subjects, a possible attempt to compensate cognitive deficit but without effectiveness.We believe that these findings could help to better characterize bMTLE, in which a dysfunction of limbic connectivity is detectable despite well-controlled epilepsy. Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adulthood , 2. ApprSince the drug-resistant MTLE has been extensively studied over the last two decades, a large amount of neuropsychological and neuroradiological data have been provided, contributing in the characterization of the corresponding epileptic syndrome. Cognitive deficits have been well documented in severe MTLE  and possFor instance, by using independent component analysis (ICA), Zhang et al. observed decreased functional connectivity (FC) at rest in the dorsal mesial prefrontal cortex, mesial temporal lobe and inferior temporal cortex of MTLE subjects . SimilarDespite the abundant fMRI literature in drug-resistant MTLE, to date only 3 studies included drug-sensitive MTLE  patients, with conflicting results possibly due to reduced sample size, heterogeneous selection criteria and different methodological approaches.In detail, analyzing FC between nodes of DMN in 12 drug-sensitive and 15 drug-resistant patients—with both mesial and lateral temporal lobe epilepsy (TLE) - Ofer et al. found a reduced local efficiency within the DMN of drug-sensitive with respect to drug-resistant subjects, irrespectively of focus lateralization . HoweverWhen directly comparing drug-sensitive patients and healthy controls (HC), Pressl et al. and Lee et al. did not find differences in FC parameters , 9, whilOf note, two of these studies were not specifically focused on MTLE but included patients with mesial and lateral TLE together. Furthermore, none of these 3 studies explored the association between FC findings and neuropsychological profile.Given this background, and differently from previous studies which were structured to compare drug-sensitive and drug-resistant patients, the aim of this study was to investigate the resting state FC specifically in subjects with bMTLE  with respect to age-matched HC, and to correlate FC data with neuropsychological scores. These analyses might contribute to better define bMTLE as a specific clinical entity within the spectrum of MTLE.Nineteen bMTLE patients  were consecutively recruited at the Center for Diagnosis and Treatment of Epilepsy of the Neurology Unit of the Azienda Ospedaliero-Universitaria Pisana. All patients fulfilled the following criteria: (i) ictal semiology suggestive of MTLE ; (ii) ictal or interictal EEG consistent with the diagnosis of MTLE ; (iii) unilateral epileptogenic temporal focus; (iv) seizure freedom of at least 24 months ; (v) riExclusion criteria were: (i) any suggestion of seizure onset outside the mesial temporal structures; (ii) evidence of bilateral EEG abnormalities or bilateral hippocampal atrophy; (iii) psychiatric comorbidities.Among the 19 patients with bMTLE, 10 subjects had a left epileptic focus while 9 had a right epileptic focus.Ten HC—matched for age, sex, handedness, and educational attainment—were enrolled.The study was approved by the local Ethics Committee in accordance with the Helsinki Declaration. Each subject gave a written informed consent to participate in the study.Demographic and clinical features recorded for each subject included sex, age, educational attainment, age at seizure onset, duration of the disease, number of antiseizure medications (ASMs) taken at the time of the enrollment, and evidence of hippocampal sclerosis (HS) on MRI.Within 3 months from recruitment, all participants underwent a battery of standardized neuropsychological tests, which included: Rey Auditory Verbal Learning Task (RAVLT) with immediate and delayed recall, to assess verbal learning and verbal memory ; Short Tt-test for continuous variables and Fisher's exact test for categorical variables.Demographic, clinical, and neuropsychological features of the two groups with left and right bMTLE were compared using Within 3 months from enrollment, all subjects underwent an MRI scan at the Neuroradiology Unit of the University of Pisa.* weighted gradient recalled echo-planar imaging (EPI) sequence  with 28 interleaved slices  angled of 30° with respect to the anterior-posterior commissural plane (AC-PC) to minimize susceptibility artifacts, repeated over 200 volumes . A high-resolution 3D Spoiled Gradient Recalled sequence was also acquired on sagittal plane . Foam cushions were used for head stabilization to reduce motion-related artifacts. We asked subjects to maintain their eyes closed and to remain awake.Images were acquired on a 3T scanner  with high-performing gradients  equipped with an eight channels head coil with ASSET technology. Rs-fMRI data were acquired using a T2In order to take into account possible regional atrophy in bMTLE patients, we performed an automated analysis of T1 structural data by an optimized VBM protocol  carried p < 0.05) by threshold-free cluster enhancement (TFCE) option , modulated and smoothed with an isotropic Gaussian kernel with a sigma of 3 mm. Statistical analyses were performed using different voxel-wise General Linear Model (GLM) with a permutation-based non-parametric testing , corrected for multiple comparisons across space  option . Age and) option .Resting state functional data were analyzed by FEAT tool part of FSL. The first four scans of each fMRI run were discarded from analysis to avoid saturation effect of magnetization. Image preprocessing also included removal of non-brain structures (by using BET) , slice-tIn order to remove artifactual signal components from subsequent analyses, we extracted the mean timecourses for WM and CSF masks for each subject. In more detail, WM and CSF images, obtained with FAST segmentation, were thresholded at 80% tissue type probability to create WM and CSF masks. These masks were registered to functional images by affine transformation, then they were applied to the preprocessed functional image in order to extract the mean timecourses for WM and CSF averaging the time series of all voxels within the masks. The single-subject time series were then used as nuisance regressors in the statistical model.Functional connectivity analysis was performed by a seed-based regression approach. Seed regions were obtained by an automated segmentation tool, FIRST (part of FSL), which extracted four ROIs from T1 structural data of each subject: right hippocampus, left hippocampus, right amygdala and left amygdala. These ROIs were registered to single-subject functional images space by affine transformation with FLIRT , then thFor each subject, first-level statistical analysis was carried out by four multiple regression analyses  with a seed timecourse regressor  and 8 nuisance covariates . Each statistical correlation map was registered by affine transformation to MNI template and both positive and negative BOLD changes were considered for the second-level analyses.Z > 2.3; cluster significance: p < 0.05). The results were adjusted for age and sex.Between-group analyses were performed by a Mixed Effect model approach , 26. Thet-test by Mixed Model in FSL by inserting clinical data or test scores as covariate variables within different GLM design matrix. The resulted Z statistical maps were thresholded using clusters determinated by Z > 2.3 and a corrected cluster significance threshold of p < 0.05.Pooling all bMTLE patients together regardless of side of the epileptic focus, we investigated the relationships between FC strength, clinical features and neuropsychological tests. We implemented one sample Demographic and clinical features of left and right bMTLE patients are illustrated in There were no significant differences between the two groups in terms of age, sex, educational attainment, age at seizure onset, duration of the disease, number of ASMs, and evidence of HS.The results of the neuropsychological evaluation are also summarized in The between-group VBM analyses revealed no significant differences in cortical GM volume both between left bMTLE patients and HC, and between right bMTLE and HC.Benign MTLE patients with left epileptic focus showed with respect to HC:- reduced FC of the affected hippocampus with bilateral inferior frontal cortices, limbic structures, superior and mid temporal cortices, and basal ganglia ;- reduced FC of the unaffected hippocampus with bilateral inferior frontal cortices, limbic structures, superior and mid temporal cortices, and basal ganglia ;- increased FC of the unaffected hippocampus with bilateral mid-posterior cinguli, angular gyri, precunei, and parieto-occipital cortices ;- reduced FC of the affected amygdala with bilateral superior and inferior frontal cortices, limbic structures, superior and mid temporal cortices, and basal ganglia ;- increased FC of the affected amygdala with bilateral precunei and parieto-occipital cortices ;- reduced FC of the unaffected amygdala with bilateral superior and inferior frontal cortices, limbic structures, superior and mid temporal cortices, and basal ganglia ;- increased FC of the unaffected amygdala with bilateral precunei, right cingulum, and parieto-occipital cortex .Benign MTLE patients with right epileptic focus showed with respect to HC:- reduced FC of the affected amygdala with bilateral inferior frontal cortices, superior and mid temporal cortices, limbic structures, and basal ganglia ;- increased FC of the affected amygdala with precunei and bilateral parieto-occipital cortices .We observed a significant positive correlation between the scores obtained in RAVLT delayed recall test and the FC of left hippocampus with bilateral inferior frontal, anterior cinguli, and superior temporal gyri , and a nNo other significant relationships between resting state FC and clinical/neuropsychological features were found.The aim of this study was to explore differences in resting-state FC in patients with bMTLE compared to HC, by using a ROI-based approach.As a main finding, we documented a marked asymmetry of FC between left and right bMTLE: left bMTLE patients showed an extended pattern of disrupted connections between limbic structures and distant brain areas, while right bMTLE subjects only exhibited a limited alteration of FC.This asymmetry has already been reported by several Authors in drug-resistant MTLE , 28. ForThe reasons for these lateralization-related differences could rely on the intrinsic cerebral asymmetry of human brain, which is responsible for the functional organization of most cognitive systems . Due to A further point to underline is that we found FC alterations in patients who were seizure-free. It is well known that recurrent seizures can modify networks connected to epileptic circuitry by neuroplasticity processes that takes place over many years , 35. TheOur findings are quite different from those obtained by the other three fMRI studies involving patients with bMTLE –9: firstNevertheless, it is very arduous to compare those results to ours, due to the different methodology used to analyze FC, which were ROI-to-ROI analyses , graph-tBelow, we will discuss more in detail the specific findings of the study.In our series, both affected and unaffected hippocampus and amygdala of patients with left bMTLE exhibited a decreased FC with bilateral inferior frontal areas, limbic structures, and temporal neocortices . These rA similar pattern of decreased FC was found in right bMTLE, although the alterations were less wide, and only involved the FC of the right amygdala .Previous fMRI studies have investigated resting-state FC changes in regions and hubs traditionally involved in LMN. For instance, in 2006 Waites et al. first raised the question of a language network dysfunction in left MTLE, observing a reduction of FC between different language and verbal memory areas in MTLE patients compared to HC .More recently, the relationship between hippocampus and LMN areas was specifically investigated by Roger et al., who documented a hypoconnectivity at rest between the affected hippocampus and fronto-temporo-parietal regions belonging to the LMN. Such hypoconnectivity was observed in both left and right bMTLE patients, but it was more pronounced in left ones . SimilarVerbal memory and language impairment is one of the most common cognitive complaints in patients with MTLE. In particular, these verbal difficulties—characterized by struggles in memorizing words, naming and fluency—have been extensively studied in drug-resistant MTLE patients –43 and aAlthough there are no fMRI studies on bMTLE specifically exploring LMN, based on our findings, we could assume that the disrupted connections toward LMN may represent the functional substrate responsible for the slight language impairment described in bMTLE.In line with this hypothesis, our left bMTLE patients—who showed a more pronounced reduction of FC toward LMN areas compared to right bMTLE—obtained significant lower scores in neuropsychological tests exploring verbal memory. Moreover, the strength of FC between left hippocampus and LMN positively correlated with performances in RAVLT delayed recall, a test exploring verbal learning and memory, thus confirming the importance of these connections in verbal tasks.Of interest, in our study also the unaffected hippocampus and amygdala in left bMTLE exhibited a pattern of disrupted connections toward LMN areas.This is in line with a previous study by Pittau et al., in which the Authors described the same altered FC for seeds in both affected and unaffected hippocampus/amygdala .Also Pereira et al. found altered connections of the unaffected hippocampus, and demonstrated that this pattern of disrupted connectivity diverged between left and right MTLE patients, being more pronounced in left MTLE group .In accordance with literature, our results might suggest that functional brain plasticity  might have occurred in bMTLE patients, with significant differences related to the epileptic focus lateralization.via its feedback pathways to the cortex (Another intriguing result of our study is the altered FC of hippocampus and amygdala toward subcortical structures . In detae cortex , 53, 54.Concerning the significance of FC between BGN and cortical areas during interictal resting state, the available data suggest that such altered connections might reflect an impaired inhibitory function of the BGN , 55.Although our patients are all drug-sensitive, we speculate that this disrupted FC between limbic structures and basal ganglia could represent a sign of the alteration in BGN due to presence of the epileptogenic network, irrespectively of the response to ASMs.In our study unaffected hippocampus and amygdala in left bMTLE and right amygdala in right bMTLE showed increased FC with areas of the posterior DMN, i.e., cinguli, precunei and parietal cortices.Patterns of hyperconnectivity toward DMN have already been described in right MTLE patients by Zhang et al.  and, morAnother possible explanation of increased FC is the development of new excitatory synapses and axonal sprouting, a phenomenon well documented by histological studies  as a conWe highlight that in our study left bMTLE patients showed increased connections of hippocampus/amygdala with DMN areas, and that such hyperconnectivity was even more widespread than in right bMTLE patients, despite worse neuropsychological performance.Moreover, pooling together patients with epileptogenic zones in either hemisphere, the strength of FC between left hippocampus and DMN negatively correlated with RAVLT delayed recall scores; in other words, patients with worse performance had a stronger FC between left hippocampus and DMN .Thus, we could speculate that the observed resting state hyperconnectivity may more likely represent the expression of an inefficient plasticity, rather than an effective compensatory phenomenon.To our knowledge, this is the first resting-state fMRI study conducted on bMTLE patients, which included cognitive evaluations and correlated the results of neuropsychological tests with fMRI data. However, due to the relatively small sample size, further studies are needed to confirm our findings.Furthermore, we specify that we separately investigated the correlation differences between HC and MTLE patients at the four ROIs. Thus, due to the intrinsically high correlation among hippocampi and amygdalae of both sides, the differences observed at each ROI may be not independent from one another, but may partially share the same origin. Therefore, the obtained results should be interpreted with caution. Lastly, another limitation of this study is the lack of neuropsychological data in HC.In summary, our study documented an asymmetrical disruption of FC in bMTLE, in relation to the side of the epileptic focus. While subjects with right focus only exhibited limited decreased connections of affected amygdala toward some areas of LMN, subjects with left focus—who performed worse in verbal memory tests—showed a wide bilateral hypoconnectivity of hippocampus and amygdala toward several areas of LMN. The strength of FC between left limbic areas and LMN correlated with better performance in verbal memory tests, thus confirming the importance of these connections in verbal memory tasks.We believe that these findings could help in understanding bMTLE pathophysiology. In particular, our results suggest that left bMTLE patients might be more prone to the disruption of limbic connectivity induced by previous seizures and, at the same time, less able to organize compensatory strategies in comparison to subjects with right focus, with consequent worse neuropsychological functioning.The original contributions presented in the study are included in the article/The studies involving human participants were reviewed and approved by the Institutional Review Board of Neurology Clinic, Santa Chiara University Hospital of Pisa. The patients/participants provided their written informed consent to participate in this study.CP and IP conceived and designed the analysis. IP, PC, and SG collected and analyzed the data. CM and CP wrote the paper. CM and LF contributed to analysis tools. FG, MC, and EB made a significant contribution in reviewing the paper. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Locomotion produces full-field optic flow that often dominates the visual motion inputs to an observer. The perception of optic flow is in turn important for animals to guide their heading and interact with moving objects. Understanding how locomotion influences optic flow processing and perception is therefore essential to understand how animals successfully interact with their environment. Here, we review research investigating how perception and neural encoding of optic flow are altered during self-motion, focusing on locomotion. Self-motion has been found to influence estimation and sensitivity for optic flow speed and direction. Nonvisual self-motion signals also increase compensation for self-driven optic flow when parsing the visual motion of moving objects. The integration of visual and nonvisual self-motion signals largely follows principles of Bayesian inference and can improve the precision and accuracy of self-motion perception. The calibration of visual and nonvisual self-motion signals is dynamic, reflecting the changing visuomotor contingencies across different environmental contexts. Throughout this review, we consider experimental research using humans, non-human primates and mice. We highlight experimental challenges and opportunities afforded by each of these species and draw parallels between experimental findings. These findings reveal a profound influence of locomotion on optic flow processing and perception across species.This article is part of a discussion meeting issue ‘New approaches to 3D vision’. T–7. T1–7]Perception and neural encoding of optic flow has historically been studied in stationary, fixating subjects. While these paradigms afforded tight control over experimental conditions necessary to investigate visual processing, they also have clear ethological limitations. Recent developments of experimental methods are however enabling a growing focus on the influence of self-motion and active behaviour on visual processing and perception –18. In tAs the review is multidisciplinary, we first introduce some primers below to provide brief contextual background useful for reading this review.direction [speed [structure and layout of objects within the environment [parse external object motion from visual motion due to self-motion .A number of monocular and binocular visual cues provide information about optic flow and self-motion to an observer. Monocular cues include structured velocity fields as well as changes in the size and spatial frequency of visual objects ,26. BinoIn this article, we review studies from primates and rodents. There are many obvious differences in the optics of the rodent and primate visual systems which have implications for optic flow processing. Whereas primate eyes face forward, most rodents have sideways-facing eyes. While such lateral placement gives rodents a larger field of view ,36, it cThe mouse retina is suitable for processing optic flow despite its low-acuity. While the density of photoreceptors in mouse retina is actually similar to that of primates –45, the The neural encoding of optic flow is best understood in non-human primates. In particular, neurons in the dorsal Medial Superior Temporal (MSTd) area, a higher visual area within the dorsal stream of the primate visual system, have large receptive fields often covering both ipsi- and contralateral halves of the visual field, indicating their suitability for the encoding of full-field optic flow caused by self-motion . Indeed,Tuning for complex optic flow patterns, as observed in primate area MSTd –57, has It is unclear to what extent an analogous area to primate MST exists in the mouse visual system. More generally, a number of studies have sought to determine whether the mouse visual system has distinct processing streams analogous to the dorsal and ventral streams in primates ,64–70, hMany recent studies have investigated the influence of locomotion on visual processing in the mouse, often leveraging the spontaneous locomotion exhibited by mice when head-fixed on a treadmill ,73. In jThe effects of locomotion on visual processing are diverse and vary between visual areas and cortical layers ,80,84,85While these changes in neural activity observed during locomotion generally indicate enhanced encoding of visual inputs, perceptual studies are thus far limited and provide mixed results as to whether locomotion also improves visual perception ,99,100, Are equivalent changes to visual processing also present in primates? A recent preprint found that locomotion also modulates visual responses in head-restrained marmosets, a non-human primate . By contAn increasing number of experimental methods are available to investigate the neural encoding and perception of optic flow by enabling the presentation of visual inputs to large areas of the visual field . These d. 2In the following sections, we highlight key findings regarding how the perception and neural encoding of optic flow are affected by movement related to locomotion. We begin each section with a description of key observations made using psychophysics in human subjects. We then discuss physiological and perceptual measurements in animal models that may provide mechanistic explanations for the observed effects, focusing on findings we feel are most relevant to perceptual phenomena. (a)a; [A striking phenomenon of human locomotion is that optic flow appears slower while walking ,116–118.figure 2a; ). This sa; ). The sua; . It is aa; , suggesta; . Importaa; ,119,120.a; ,116 and a; , demonstIs there a neural mechanism for optic flow to be perceived as being slower during locomotion? It is now well established that the encoding of visual speed by neurons throughout the mouse visual system is dependent on concurrent self-motion signals ,80,81,95 (b)b; [What is the function of the slowing down of perceived optic flow speed during locomotion? One hypothesis is that it enables increased sensitivity to optic flow speed . This hyfigure 2b; ). A simib; . Subjectb; .We recently showed that the visual speed of moving dot fields can be better decoded from neural activity in locomoting mice , raising (c)The subtractive effect of locomotion on the perceived speed of optic flow may also reflect perceptual stabilization of the visual environment , enablinSelf-motion signals can also improve the accuracy of heading direction perception from optic flow in the presence of interfering object motion. While humans and non-human primates can accurately judge self-motion heading from optic flow in stationary environments, the presence of object motion can bias estimates of heading  area and MSTd , which aIn the mouse, the higher-order visual thalamic Lateral Posterior (LP) nucleus  contains neurons tuned for negative correlations between visual speed and running speed ,80. Proj (d)a; [figure 5b; [The perception of self-motion is a multisensory experience, combining visual, proprioceptive and vestibular signals with a range of other cues. Humans and non-human primates can integrate visual and nonvisual cues to estimate heading direction ,144 and figure 5a; ,149–151)gure 5b; –148. Notgure 5b; , indicatIn primates, multisensory perception of heading direction has been strongly linked to activity of neurons in MSTd which respond to combinations of optic flow and vestibular input using a reliability-dependent weighted sum ,154. In Recent experimental findings demonstrate that mice can also combine vestibular and visual cues to improve perceptual discrimination of angular velocity , as has  (e)Multisensory integration leverages the relationships between different senses to enable more precise perceptual judgements ,164. HowIn another set of experiments subjects walked on a treadmill while being pulled by a tractor moving either faster or slower than treadmill speed so as to alter the gain of optic flow associated with locomotion and induce visuomotor recalibration . AfterwaA common perceptual bias in virtual reality environments is the underestimation of distances. However, experience of closed-loop feedback can significantly improve these perceptual judgements –174, indIt has been proposed that multisensory cue calibration consists of two distinct processes—‘unsupervised’ and ‘supervised’ calibration ,176. Unsa), but when the more reliable cue was inaccurate both cues were calibrated together as a combined percept (figure 6b). As a result, the reliable, inaccurate cue became more accurate, however, the less reliable, initially accurate cue became less accurate [Multisensory cue calibration underlying the perception of heading direction has been investigated using an adaptation paradigm ,176. In figure 6accurate , in lineaccurate .Figure The neural mechanisms underlying cue calibration of visual and nonvisual self-motion signals have not been explicitly investigated in the mouse. A subset of V1 neurons has been identified that may play a role in detecting discrepancies between optic flow and nonvisual self-motion signals, as would occur during unsupervised calibration . These n. 3 (a)A key challenge for future research is dissociating effects of self-motion from co-occurring changes in behavioural and brain state. The mouse, in particular, has provided a number of insights into the effects of behavioural state on visual processing and perception ,183,184. (b)To what extent does the integration of visual and nonvisual cues for self-motion occur without conscious awareness? Humans automatically adjust their locomotion speed to changes in optic flow patterns ,192–194 . 4In this review, we brought together findings from distinct fields of research. While the influence of self-motion on optic flow perception has been most-studied in humans and non-human primates, the effects of locomotion on neural activity are best characterized in mice. We believe each of these species affords unique insights into the influence of self-motion on optic flow processing and perception, and ultimately that a multi-species approach, therefore, provides the best way forwards. To this end, we hope this review provides a useful starting point by highlighting existing cross-over in these areas of research as well as the distinct experimental opportunities afforded by each of these species.Experimental approaches to investigate vision during movement have had various constraints in available methodologies for each species. For example, non-human primate studies have generally investigated the influence of vestibular signals on optic flow processing and perception during passive movement using motion platforms. However, developing technologies are expanding experimental opportunities  allow for precise control of binocular visual stimulation to a subject during active unrestrained movement. The continued development of this technology should allow for more comfortable, realistic and immersive visual experiences. Moreover, a number of groups have begun to combine head-mounted displays with non-invasive recording methods such as electroencephalography , and funAs the availability of experimental technologies increases, so does the capacity for analogous experiments across species. This in turn allows for more direct comparisons of the effects of self-motion on optic flow processing and perception. Indeed, advances in training protocols mean that mice can now be routinely trained to perform a range of visual psychophysics tasks ,201–204


Background and objectives: Dermoscopy is a useful tool for the early and non-invasive diagnosis of skin malignancies. Besides many progresses, heavily pigmented and amelanotic skin tumors remain still a challenge. We aimed to investigate by dermoscopy if distinctive morphologic characteristics of vessels may help the diagnosis of equivocal nodular lesions. Materials and Methods: A collage of 16 challenging clinical and dermoscopic images of 8 amelanotic and 8 heavily pigmented nodular melanomas and basal cell carcinomas was sent via e-mail to 8 expert dermoscopists. Results: Dermoscopy improved diagnostic accuracy in 40 cases. Vessels were considered the best clue in 71 cases. Focusing on the diameter of vessels improved diagnosis in 5 cases. Conclusions: vascular diameter in addition to morphology and arrangement may be a useful dermoscopic clue for the differential diagnosis of clinically equivocal nodular malignant tumors. Several lines of evidence demonstrate the value of dermoscopy in the diagnosis of pigmented and non-pigmented skin tumors ,2. BesidWe recently noticed by reviewing our database that heavily pigmented BCCs commonly exhibit blue-to-blue-black structures in addition to some large caliber vessels, whereas such vessels were never seen in heavily pigmented nMELs.The latter observation may be explained by another feature we noticed, namely, that amelanotic nMEL in contrast to nBCC or other types of low-risk nodular carcinomas  typically reveal dense, short and fine, polymorphic small caliber micro-vessels, which may be easily covered by the presence of heavy pigmentation in the case of nMEL. In contrast, even large amounts of pigmentation do not completely hide the classical large superficial macro-vessels of nBCCs.We tested our hypothesis by sending a collage of 16 challenging clinical images of 8 amelanotic and 8 heavily pigmented nodular lesions (8 melanomas and 8 BCCs) and their corresponding dermoscopic images . Only in 3 cases, a diagnosis of melanoma was associated with the observation of small diameter vessels as best dermoscopic findings. Prominent large caliber vessels were correctly considered best clue for the diagnosis of BCC in 4 cases. Focusing on the diameter of vessels improved diagnosis in 5 cases.The results of our survey are shown in Dermoscopic vessels features considered best diagnostic clue are listed in The use of dermoscopy in clinical practice has been shown to increase diagnostic accuracy both for pigmented and nonpigmented skin tumors ,6.While specific dermoscopic features are easily recognizable in most pigmented tumors, when assessing nonpigmented or hypopigmented skin tumors, reaching out for a diagnosis can be a challenge and the visualization of vessels, usually not visible to the naked eye, with the identification of a characteristic morphology can be the only key to the dermoscopic diagnosis.Moreover, regardless of pigmentation, the dermoscopic recognition of nodular malignant skin lesions is also difficult, due to the fact that the tumor often lacks the specific criteria for malignancy ,7.In 2001, the Board of the Consensus Net Meeting on Dermoscopy discussed a two-step algorithm for the classification of pigmented skin lesions .In 2010, a revised two-step algorithm has been described, taking into consideration polarized dermoscopy and vascular architecture .In the same year, a three-step algorithm for dermoscopic diagnosis of non-/hypopigmented skin tumors, including vascular morphology, architectural arrangement of vessels  and other optional criteria  has been proposed . Among tTo date, six morphologic categories of vascular patterns have been described in literature, including comma-like vessels, dotted vessels, linear irregular vessels, hairpin vessels, glomerular vessels and arborizing vessels . Except Moreover, it is necessary to remember that clinically flat and superficial tumors usually show different vascular morphology compared with their thick and nodular counterparts .Sometimes highly aggressive nMEL may be difficult to distinguish from low-risk nodular keratinocyte cancer, such as nBCC.Surgical excision is the first-choice treatment for both entities. Nodular basal cell carcinoma usually doesn’t need an urgent referral, whereas in case of nMEL, early recognition and surgical removal is key for maximizing survival outcomes of patients.Based on our personal clinical experience and according to our preliminary results, the observation of vessels caliber and density by dermoscopy may help in distinguishing tumors with a longstanding progressive and indolent growth  from tumors with aggressive behavior .When dermoscopy of nodular non-/hypopigmented lesion reveals small caliber vessels, usually with high density, a suspicion of highly aggressive malignancy should be considered in order to perform a biopsy and obtain a prompt histological diagnosis. Indeed, we found that non-/hypopigmented nodular melanoma typically shows densely packed vessels of small diameter , whereasA similar situation can be observed confronting nodular poorly differentiated squamous cell carcinoma (SCC) with keratoachantoma, that are typically raised non pigmented skin lesions. Hairpin-like vessels occur more frequently in well differentiated SCC (such as keratoacanthoma) . They usIn case of pigmented nMEL, structureless blue pigmentation, areas of pink and black colors and/or ulceration can be the clues for the diagnosis. Vascular structures, when visible, are located at the periphery of the lesions as polymorphous vessels and milky-red globules  Figure .Pigmented nodular BCCs are instead characterized on dermoscopy by blue-grey ovoid nests or blue-grey dots/globules usually associated with arborizing vessels . At the In both cases, based on our personal experience, in the absence of any specific dermoscopic features, an aggressive behavior  should be hypothesized when on dermoscopy the lesion exhibits higher density of vessels of small diameter. Conversely, an indolent course  should be assumed for tumors with lower density of larger caliber vessels, typically visible also in presence of heavy pigmentation.These considerations could be useful in the triage setting of equivocal and suspicious hypo-/hyperpigmented nodular lesions, in order to identify those requiring prompt biopsy.These preliminary results suggest that vascular diameter in addition to morphology and arrangement may be a useful dermoscopic clue for the differential diagnosis of clinically equivocal nodular malignant tumors.Based on our experience, dense and small caliber vessels in nodular lesions are suspicious for high malignancy , whereas larger superficial vessels with low density suggest a locally aggressive behavior.These preliminary observations on the role of vascular diameter as a new diagnostic dermoscopic clue of malignancy should be validated in a prospective study, collecting a large series of nodular lesions. The differentiation of clinically and/or dermoscopically equivocal pigmented and non-/hypopigmented nodular BCCs and melanomas is indeed important especially in order to expedite surgical treatment of aggressive tumors and provide the best care, as early as possible.


Hydrogels are biocompatible polymer systems, which have become a hotspot in biomedical research. As hydrogels mimic the structure of natural extracellular matrices, they are considered as good scaffold materials in the tissue engineering area for repairing dental pulp and periodontal damages. Combined with different kinds of stem cells and growth factors, various hydrogel complexes have played an optimistic role in endodontic and periodontal tissue engineering studies. Further, hydrogels exhibit biological effects in response to external stimuli, which results in hydrogels having a promising application in local drug delivery. This review summarized the advances of hydrogels in oral science research, in the hopes of providing a reference for future applications. Hydrogel is a polymer network system formed by cross-linking the reaction of monomers and comprised of water-encapsulating networks . It distThe three-dimensional network structure and viscoelasticity of the hydrogel are similar to the extracellular matrix (ECM), which can mimic the three-dimensional microenvironment of cells, support cells attachment, and induce cells proliferation and differentiation. Because of their favorable properties , hydrogeOral health is considered an important part of general health and quality of life , and oraDental pulp, also called endodontium, is located inside the pulp cavity of the tooth. Pulp tissue mainly contains nerves, blood vessels, lymphatic and connective tissues, as well as odontoblasts arranged in the outer periphery of the pulp, whose role is to produce dentin. Dental pulp plays an essential role in the maintenance of blood circulation and homeostasis, sensory transmission, and regeneration of dentin . After cPulp regeneration has raised great concerns in the treatment of pulp disease during the past few decades. The American Association of Endodontists (AAE) defines pulp regeneration as, “use biological means to replace damaged dental tissue, root, pulp–dentin complex and other structures to form functional pulp-like tissue”. Studies on pulp regeneration mainly take histoengineering principles and means to induce differentiation of pulp–dentin complex through stem cells–scaffold–growth factor complexes , so as tThe scaffold materials play a variety of roles during this procedure , not onlPulp regeneration with hydrogels has become a reality and has been promoted and verified through molecular and developmental biology, as well as biomimetic principles and histological approaches ,32. The Rosa et al. confirmed that stem cells from exfoliated deciduous teeth (SHED) can generate a functional dental pulp when injected into full-length root canals . SHED suChrepa et al. tested the hypothesis that a Food and Drug Administration-approved hyaluronic acid-based injectable gel may be a promising scaffold material for regenerative endodontics. Improvement of stem cells of the apical papilla (SCAP) survival, mineralization, and differentiation into an odontoblastic phenotype was observed in this research .Chitosan, a natural biopolymer derived from chitin, was also found to be able to promote the differentiation and proliferation of dental pulp stromal/stem cells (DPSCs) . Feng etRGD-alginate hydrogels significantly enhance cell adhesion and proliferation . An RGD-The above natural hydrogels are biocompatible, biodegradable, and optimistically bioactive with the ability to release bioactive molecules ,42. HoweCurrently, injectable composite hydrogels have become a promising application option in pulp tissue engineering ,46. UV lHowever, one of the main limitations of hydrogels is the spatial manipulation restriction, i.e., researchers are unable to fully control the organization and interactions of multiple cells, so the overall morphogenesis of tissues cannot be guaranteed totally. Luckily, combined with superior spatial control of 3D cell printing, this problem can be overcome in the near future ,51. The Currently, in animal models, it appears to be possible to regenerate pulp and dentin, although challenges include the absence of dentin tubular formation, as well as difficulties in dealing with smaller tubes due to angiogenesis ,55 Summ.The use of growth factors and hydrogel scaffolds accelerates clinical translation and enhances dental tissue engineering, which is expected to be the best biological solution in endodontic medicine . HydrogeRecent studies suggested that a hydrogel complex  may be aPeriodontal disease is a worldwide health problem that exerts a negative influence on patients. Periodontitis is a chronic inflammatory disease of the periodontal tissue caused by pathogenic microorganisms, with the characteristic of the destruction of teeth supporting structures . InflammTraditional therapies, including mechanical plaque removal and scaling, are not effective enough in the long term . This inSome strategies have been conducted to regenerate periodontal tissue, such as the guided tissue/bone regeneration membranes . These aRecently, hydrogels have been widely applied as a sustained-release system and scaffold materials in periodontal tissue regeneration research ,66. WhilIn the field of alveolar bone regeneration, hydrogels based on hyaluronic acid (HA) have been used with different strategies to augment their mechanical properties. In Miranda’s study, modified hyaluronic acid (HA) and chitosan (CS) were employed to create a hybrid CS-HA hydrogel scaffold , which cIn addition to cell encapsulation, the combination of GelMA and polyethylene glycol (PEG) has been used for bioprinting regeneration of periodontal tissue . PeriodoDuarte Campus et al.  investigPDL, also known as the periodontal ligament, is a highly organized tissue between the cementum and alveolar bone. PDL is capable of taking extremely high forces, which poses a huge challenge for tissue engineering . ConstruA major challenge in periodontal regeneration lies in the complexity  of tissuScaffold materials support tissue regeneration to a certain extent, but they may not have the ability to induce tissue regeneration individually. Growth factors, a class of active signaling molecules, can regulate cell growth and other cellular functions by bonding to specific, high-affinity cell membrane receptors. Researchers combined collagen hydrogel scaffold with fibroblast growth factor-2 (FGF2) . This grChien’s group applied an injectable and thermosensitive chitosan/gelatin/glycerol phosphate hydrogel to provide a 3D environment for transplanted induced pluripotent stem cells (iPSCs) and to enhance stem cell delivery and engraftment . The iPSXu’s group integrated chitosan, β-sodium glycerophosphate (β-GP), and gelatin to prepare an injectable and thermosensitive hydrogel, which intended to terminate the alveolar bone resorption with simultaneous anti-inflammation and promote periodontium regeneration . The traA supramolecular hydrogel, SDF-1/BMP-2/NapFFY, was fabricated by combining NapFFY with SDF-1 and BMP-2 recently . It was In short, periodontal tissue engineering with multiple kinds of hydrogels loaded with various mesenchymal stem cells or bioactive molecules is a promising therapy for an injured periodontal environment. Synthesized hydrogels have great potential for future clinical application, which urges more concerns and investigations in this field. No doubt these novel hydrogels could be able to alter transplantation in the clinic in the near future to repair periodontal defects .As the common oral cavity diseases locate relatively superficially, the best therapy to control may be regional treatment. Conventional oral drug delivery systems (DDS), such as lozenges and oral spray, work to deliver active drugs topically, while disagreements aroused because of their short residence and instability in saliva . PotentiDifferent kinds of DDSs are being developed  includinAs is depicted in the above text, hydrogels can absorb a large amount of liquid and swell due to their fantastic hydrophilicity, with good viscoelasticity and longer residence time. They are introduced as a novel DDSs to encapsulate various therapeutic agents/compounds and release them in a controlled manner . A recenIn pathological conditions, specific changes would occur in the local microenvironment of the tissue, such as local pH reduction under various conditions. As a drug delivery carrier, certain hydrogels complexes are fabricated to respond to local pathological stimuli and achieve delivery at a very point, affecting the biological distribution and toxicity of drugs.Several researchers constructed an agarose hydrogel system for biomimetic mineralization of dentin  and enamAntimicrobial activity improves when hydrogels are loaded with antibiotics . Aksel eIt is certain that periodontitis initiates from uncontrolled plaque which includes various microorganisms . BacteriHydrogel administration is conducted by injecting into the infected periodontal pocket ,115,116,Oral mucosal diseases such as lichen planus, aphthous stomatitis, oral mucositis, and wounds mostly require effective topical therapies. The primary problem in topical administration of therapeutic agents lies in the low residence time on the smooth and moist surface of oral soft tissue .® 980 was combined with lipid nanoparticles (NLC) for buccal administration [Hydrogels can be applied in mucosal injury as well for their elastic, adhesive, and degradable characteristics. Andreopoulos et al.  reportedstration . Zhang estration , which oThe proposal of a thermally sensitive mucoadhesive hydrogel aimed to facilitate the treatment of oral mucositis, which contained Trimethyl chitosan (TMC) and methylpyrrolidinone chitosan (MPC) ,121. MixAntioxidants were also mixed with hydrogels to play roles in the oral cavity, and an isoguanosine–tannic acid (isoG-TA) supramolecular hydrogel was fabricated with leukoplakia (OLK) by Ding et al. . ResultsIn conclusion, there are various formulations based on hydrogels in DDSs. This article reviews the potential of hydrogel to treat pathogenic oral cavity conditions. The applications of hydrogels for oral science research are wide, ranging from tissue reconstruction to oral disease therapy. The advantages of the application of hydrogel complexes include physical property , the str


The polygenic and multifactorial nature of many psychiatric disorders has hampered implementation of the personalized medicine approach in clinical practice. However, induced pluripotent stem cell (iPSC) technology has emerged as an innovative tool for patient-specific disease modeling to expand the pathophysiology knowledge and treatment perspectives in the last decade. Current technologies enable adult human somatic cell reprogramming into iPSCs to generate neural cells and direct neural cell conversion to model organisms that exhibit phenotypes close to human diseases, thereby effectively representing relevant aspects of neuropsychiatric disorders. In this regard, iPSCs reflect patient pathophysiology and pharmacological responsiveness, particularly when cultured under conditions that emulate spatial tissue organization in brain organoids. Recently, the application of iPSCs has been frequently associated with gene editing that targets the disease-causing gene to deepen the illness pathophysiology and to conduct drug screening. Moreover, gene editing has provided a unique opportunity to repair the putative causative genetic lesions in patient-derived cells. Here, we review the use of iPSC technology to model and potentially treat neuropsychiatric disorders by illustrating the key studies on a series of mental disorders, including schizophrenia, major depressive disorder, bipolar disorder, and autism spectrum disorder. Future perspectives will involve the development of organ-on-a-chip platforms that control the microenvironmental conditions so as to reflect individual pathophysiological by adjusting physiochemical parameters according to personal health data. This strategy could open new ways by which to build a disease model that considers individual variability and tailors personalized treatments. Personalized medicine aims to predict disease susceptibility, achieve an accurate diagnosis, and select the most effective therapeutic option with the least adverse effects for each patient ,2. PersoBefore its psychiatric application, personalized medicine had brought significant diagnostic and therapeutical advances in oncology where the identification of the molecular target of the drug, the mechanisms of resistance to targeted compounds, and the best pharmacological combinations for a specific tumor promoted the optimal individual treatment selection .Due to the lack of practicable diagnostic tests, along with the inherent complexity of psychiatric disorders, the reliance on diagnostic manuals make personalized medicine in psychiatry implementation more challenging than in other medical specialties . The curA diagnostic system using a combination of several psychopathological dimensions defined along with a range of severity, from normality to the full pathological expression, has been proposed because the categorical approach fails to fully express mental illness complexity . HoweverAnimal models have widely contributed to understanding several brain pathological mechanisms and developing effective drugs; however, fully reproducing the complexity of human psychiatric diseases is substantially impossible . MoreoveFinally, research has been hindered by the inaccessibility to human live brain tissue and the difficulty in isolating and culturing primary human neurons. Postmortem brain studies are burdened by confounding variables, such as treatment history, drug or alcohol abuse, and cause of death, and cannot provide information on temporal psychiatric disease changes in which molecular and cellular alterations may occur years before the clinical symptom presentation .The discovery of induced pluripotent stem cell (iPSC) technology has opened unprecedented opportunities as the limitations described above underscore the need for psychiatric disease models based on human cells. In the next sections, we summarize the main concepts concerning iPSCs and provide an overview of their preliminary applications in the field of personalized psychiatry (PP).These iPSCs consist of artificial stem cells that are induced (or “reprogrammed”) in culture from somatic cells using different transcription factors. Stem cells are pluripotent cells derived from the embryo (embryonic stem cells [ESCs]) and various postnatal tissue sources, characterized by the ability of self-renewal (proliferation) and differentiation into various adult cell types, and thus called pluripotent stem cells.In 2006, Takahashi and Yamanaka  demonstrRetroviruses are extensively used for integrating exogenous genes into the genome to reprogram somatic cells and produce iPSCs. However, some risks could limit their use in iPSC-based therapies, such as those proposed to regenerate cardiac cells after myocardial infarction  or insulOver the recent years, iPSC application has been frequently associated with gene editing. This technique targets the disease-causing gene to deepen illness pathophysiology and conduct drug screening . Gene edFinally, it should be noted that iPSC-derived neurons express embryonic features that directly show the genetic mutation effect on the cell phenotype but erase epigenetic changes due to age or disease progress . AlthougBrain organoid (BO) is a stem cell-derived 3D tissue that recapitulates early cerebral developmental events and simulates the human brain’s architecture and functionality in vitro. The possibility of generating organoids relies on stem cells’ intrinsic self-organization properties into 3D architectures that contain multiple cell types and maintain some specific function and spatial human brain organization ,34.The 3D context, more than 2D culture systems, allows the study of alterations in neuronal migration, cortical layering, and axon guidance that characterize neurodevelopmental and neuropsychiatric disorders, which often do not display observable neuroanatomical phenotypes . TechnicThe generation of BO began with the development from iPSCs or ESCs of embryoid bodies (Ebs) containing three layers, namely, endoderm, mesoderm, and ectoderm. Neural tissue in humans develops from the ectoderm; thus, Ebs were placed in neural induction media that promote neuronal differentiation after 1 month of culture and then embedded in scaffold support to grow complex organoids. The embedded organoids were transferred into a spinning bioreactor for further maturation and preservation through enhanced nutrient absorption. Over the next 1–2 months, the cerebral tissue gradually expanded to form different brain regions surrounded by cortical tissue .The best medical application of iPSCs is generally thought to be in cell transplantation therapy; however, disease modeling and drug screening could be as relevant as cell therapy, making iPSCs attractive candidates for future PP development. Modeling of iPSC-disease reproduces a pathologic condition in vitro by reprogramming the patient’s somatic cells into iPSCs, followed by redifferentiating the patient-specific iPSCs into disease-specific cells. Additionally, drug screening procedures can use the derived cells from humans for which the test compounds are therapeutically intended.Meanwhile, iPSCs may be derived from individuals with various monogenic and polygenic disorders thus providing a precious resource for understanding the underlying molecular and cellular mechanisms through personalized models of psychiatric diseases. Moreover, cells are reprogrammed to a very early stage of development; thus, they can provide information on developmental or differentiation defects, as well as the temporal sequence of events, in the early stages of disease progression. The timeline for iPSC differentiation into CNS cells follows the same trajectory as in the developing embryo; thus, these cells are handy tools to study psychiatric disorders, including schizophrenia (SZ) and neurodevelopmental disorders, such as autism spectrum disorder (ASD), where neurodevelopmental alterations are believed to feature. Moreover, BO—which contains multiple organ-specific cell types with function and spatial organization similar to a human brain—has opened up a new avenue for investigating psychiatric disorders.Finally, iPSCs could offer the possibility of overcoming the ethical concern of destroying a potential human life and the technical limitations related to ESC use. Producing a large number of ESCs or deriving them from patients with diseases is impossible; thus, their use is limited to studies of normal cellular function or the introduction of known engineered genetic changes .In the following paragraphs, we provide an overview of preliminary studies that used iPSCs in severe psychiatric disorders.Schizophrenia (SZ) is a severe mental illness that is associated with subtle brain cortical structure changes and is characterized by the following symptoms: delusions, hallucinations, disorganized thinking, abnormal motor behavior, and negative symptoms .In patients with SZ, iPSC studies are mainly devoted to investigating the pathogenesis of the illness .The first human study by Brennand et al. found diminished neuronal connectivity, neurite number, and PSD95 synaptic protein levels, as well as altered gene expression profiles of the cAMP, wingless-related integration site (Wnt) signaling pathways, and glutamate receptors in iPSC-derived neurons of patients with SZ, compared to controls. The Wnts are secreted factors that regulate cell proliferation and differentiation during embryonic development and act by activating diverse signaling cascades inside the target cells. These alterations are consistent with those described in the postmortem brain of patients with SZ and animal models of SZ and could be ameliorated with the antipsychotic loxapine . More reNarla et al. identify the nFGFR1 signaling, which integrates signals from diverse pathways that are characterized by SZ-linked mutations, as a common altered mechanism and a potential therapeutic target in investigated patients .Hippocampal neurogenesis aberrations have been implicated in SZ pathogenesis . Thus, iThe mitochondrial tricarboxylic acid (TCA) cycle  is known to largely satisfy the energetic neuron demand, thereby generating approximately 90% of cellular reactive oxygen species (ROS). Mitochondrial dysfunction enhances ROS formation, which negatively acts on mitochondrial function, leading to oxidative damage that affects several cellular components, such as lipids, DNA, and proteins. The human fetal brain is particularly vulnerable to oxidative damage due to its high oxygen consumption, high ROS basal level production, and less developed antioxidant defense mechanisms relative to the adult brain. Collectively, the studies in iPSC-NPCs and neurons of patients with SZ showed perturbed mitochondrial respiration and morphology along with signs of increased oxidative damage compared to controls .Globally, SZ iPSC-derived NPCs demonstrated altered migration and Wnt signaling , increasBO studies in patients with SZ have revealed several phenotypes that may be associated with early neurodevelopmental defects, such as nFGFR1 signaling  and immuNotaras et al. observed that in SZ BO, about 2.62% of global proteome was differentially regulated, with a depletion of factors that support neuronal development, differentiation, and/or function . MoreoveFinally, Page  identifiFURINrs4702) and four top-ranked SZ-eQTL genes , demonstrating a synergistic effect between SZ-eQTL genes that converge on synaptic function. The single and combinatorial CRISPRa/i manipulations of common variant loci and genes in human neurons suggest that synergy between risk variants may impact SZ risk.In addition, CRISPR-mediated gene editing has contributed to our understanding of risk variants for SZ, which include common single-nucleotide variants (SNVs) with small effect sizes and copy-number variations (CNVs) with greater penetrance. By integrating GWAS and post-mortem brain expression quantitative trait loci (eQTL) studies, common variants that affect SZ risk through regulation of gene expression have been identified. Schrode  applied It should be noted that some of the biological alterations that emerged from iPSC-based studies appeared not to be specific to SZ but to be shared by several disorders. Particularly, studies have identified in disrupted in schizophrenia 1 (DISC1) a gene associated with diverse mental disorders, following the finding that its coding sequence is interrupted by a balanced translocation in a Scottish family, in which the translocation co-segregates with SZ, bipolar disorder, and major depressive disorder . The varGenerated cerebral organoids by DISC1-disrupted iPSCs showed disorganized structural morphology and impaired proliferation, which is phenocopied by Wnt agonism and rescued by Wnt antagonism . The shaOverall, the iPSC-based studies in patients with SZ suggest the presence of an early genetic dysregulation leading to altered neuronal and brain development.Major Depressive Disorder (MDD) is a common and severe mental disorder that is characterized by one or more major depressive episodes, defined as discrete periods of at least 2-week duration, but generally longer, in which at least five of the following nine symptoms are present: depressed mood, loss of pleasure or interest, significant appetite disturbance/body weight change, sleep disturbance, loss of energy, psychomotor changes, excessive guilt and/or worthlessness, decreased concentration, and recurring death and/or suicide thoughts . UnsatisTherefore, iPSC-based studies on MDD have focused on treatment-resistant depression (TRD), which is defined as the failure to achieve a reduced baseline depressive symptomatology of at least 50%, after at least two antidepressant treatment trials of adequate dosage and duration .A study on patients with MDD showed that iPSCs derived from patients who are non-remitted with selective serotonin reuptake inhibitor (SSRI) antidepressant therapy displayed serotonin-induced hyperactivity downstream of upregulated excitatory serotonergic receptors (5-HT2A and 5-HT7) in contrast to what was seen in healthy and remitted patient-derived iPSCs. Lurasidone, which is a high-affinity 5-HT2A and 5-HT7 antagonist, partially rescued 5-HT-induced hyperactivity in non-remitted patient-derived iPSCs .protocadherin-α gene expression compared to healthy controls and remitted patients [Another study of the same research group revealed no significant differences in serotonin release/reuptake or genes related to serotonin pathways in iPSCs and serotonergic neurons of SSRI-treated patients with MDD . Howeverpatients . The propatients .In MDD lymphoblastoid cell lines (LCLs) reprogrammed to iPSC and differentiated into cortical neurons, Avior  identifiKetamine, a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, is a promising treatment for patients with TRD, providing significant depressive symptom improvement within hours of intravenous administration. An iPSC-based study of ketamine’s antidepressant mechanisms of action supported the leading hypothesis that ketamine can enhance structural plasticity through the AMPA glutamate receptor-driven raise of Brain-Derived Neurotrophic Factor levels, leading to an increased synaptic number and function in the prefrontal cortex .The mechanisms underlying the prolonged antidepressant effects (1 week) after a single ketamine infusion are poorly understood. The triggering of synaptic function and plasticity was hypothesized because a ketamine half-life of approximately 2 h cannot explain the long-lasting antidepressant effects. A study that supported this view demonstrated that dopaminergic neurons that are differentiated from iPSCs obtained from healthy donors who are exposed for 6 h to ketamine metabolite -hydroxynorketamine  produced dendrite outgrowth when measured 3 days after exposure .Bipolar disorder (BD) is characterized by the recurring swing between the opposite mood states of major depressive episodes and mania (BD type I) or hypomania (BD type II). Mania is more severe than hypomania and causes markedly impaired social or occupational functioning or necessitates hospitalization. Both manic and hypomanic episodes are characterized by expansive or irritable mood, increased activity and self-confidence, talkativeness, and distractibility, as well as decreased need for sleep, racing thoughts, and poor judgment (5). First-line BD treatment includes mood stabilizers, mainly lithium. The IPSC-based studies on BD are focused on elucidating the pathogenetic mechanism by also examining the detailed effects of lithium and/or other BD drug exposure on the different signaling pathways .The first study that investigated iPSC-derived neuronal cells from patients with BD revealed that the gene expression encoding membrane-bound receptors and ion channels, particularly transcripts involved in calcium signaling, was significantly increased in the neurons generated from three patients with BD compared to those obtained from three healthy controls . AdditioThe expression of multiple BD-linked genes that are involved in neuronal development, differentiation, and neuroplasticity are regulated by microRNAs (miRNAs), which are small, non-coding RNAs. In particular, miR-34a is predicted to target genes implicated as risk factors for BD and is reduced by lithium and valproic acid, two mood stabilizers that are widely prescribed to prevent depressive and manic recurrences .An increased miR-34a expression has been detected in postmortem brain tissue, directly induced neuronal cells, and iPSC-derived neuronal cells from patients with BD compared to healthy controls . The oveIn addition, CXCR4 (CXC chemokine receptor-4) expressing NPCs were analyzed from two BD-affected brothers and their two unaffected parents in a family-based paradigm that has the advantage of controlling for the genetic background . The stuKim et al. studied iPSC-derived neurons obtained from patients with BD type I and their unaffected siblings from an Old Order Amish pedigree with a high BD incidence . The obsAccumulating evidence suggests a relationship between imbalanced inflammatory response and BD. Astrocytes participate in the brain inflammatory cascade after being activated by pro-inflammatory cytokines. Vadodaria  demonstrStudies on iPSC-derived neuronal cells’ electrophysiological activity may help predict the lithium response and develop novel drugs for BD treatment. Differential hyperexcitability responses to in vitro lithium treatment in iPSC-derived hippocampal dentate gyrus-like neuronal cells from six patients with manic BD type I and four unaffected individuals were detected. Particularly, the hyperexcitability phenotype in BD was selectively reversed by lithium treatment only in neurons that are derived from patients who responded to lithium treatment, suggesting that this model of iPSCs might help develop new drugs . NotablyOsere  exploredThe first comprehensive study that compared BO generated from patients with BD type I and healthy individuals demonstrated transcriptomic differences with gene downregulation involved in cell adhesion, neurodevelopment, and synaptic biology, along with the gene upregulation involved in immune signaling in patients with BD type I .Autism Spectrum Disorder (ASD) refers to a broad range of lifelong neurodevelopmental conditions characterized by impaired social abilities and cognitive functions. ASD can be of unknown polygenic etiology (idiopathic) or a specific syndromic disorder, such as Fragile X, caused by a single gene mutation .Since iPSCs recapitulate aspects of the neuronal development process while preserving the patient’s genetic background, they are frequently used to model idiopathic ASD, for clarifying pathogenetic mechanisms .The increased proliferation and differentiation abnormalities of iPSC-derived NPCs from patients with idiopathic ASD with macrencephaly compared to non-ASD controls with normal brain size were suggested to result in early brain overgrowth . The treUsing gene expression analyses on patients with ASD iPSC-derived BO, Mariani et al. showed the overexpression of the gene FOXG1, which generates an overproduction of GABAergic neurons, and, in turn, an increased brain volume and imbalanced excitation and inhibition systems in the developing cortex . UnfortuFragile X syndrome (FXS) is the most prevalent single-gene form of ASDs and is characterized by cognitive impairment, defective communication, hyperactivity, and impulsivity. In particular, FXS is caused by transcriptional FMR1 gene silencing on the X-chromosome during embryonic development with the consequent loss of Fragile X Mental Retardation Protein (FMRP) expression. This FMRP is a selective RNA-binding protein that regulates the translation of many genes at the synaptic sites. The lack of FMRP leads to aberrant differentiation in human iPSC-derived neural progenitor cells .Conventional bidimensional and 3D FXS models based on isogenic FMR1 knock-out mutant iPSCs display altered cortical neuron gene expression and impaired differentiation compared with the wild-type human iPSCs. Cortical BO models show an increased number of glial cells, such as astrocytes, and bigger organoid size, which suggests that FMRP is required to correctly support neuronal and glial cell proliferation and the correct excitation/inhibition ratio in human brain development .Nonsense-mediated RNA decay (NMD) is a cellular surveillance pathway that safeguards the quality and stability of mRNA transcripts by targeting them for degradation if altered. Deficiency in FMRP results in hyperactivated NMD in FXS fibroblast-derived iPSCs, with a negative consequence on iPSC maturation to neurons .The iPSC technology allows the capturing of the SZ genotype, including genetic risk factors, along with their effects on cellular and molecular endophenotypes during early neurodevelopment. This approach supports the neurodevelopmental hypothesis of SZ, stating that the disruption of early brain development increases the risk of later manifest psychotic symptoms. Patient-derived iPSCs have proven to be a powerful tool in identifying SZ early neurodevelopmental defects, having revealed alterations in neuronal differentiation ,48,49, mAdditionally, the studies showed perturbed mitochondrial respiration function and morphology associated with signs of increased oxidative damage in SCZ iPSC-NPCs and neurons relative to controls ,47. ThesIn the development of MDD, environmental factors play a central role, to the extent even of inducing epigenetic modifications, which are lost during the reprogramming process. This loss may hinder identifying the multiple pathways involved in MDD pathogenesis and may impact the study of antidepressant resistance, one of the main focuses of the iPSC approach to MDD. It is known that environmental factors, particularly childhood maltreatment, are associated with poor treatment response in MDD. Despite these limitations, iPSC studies are providing important information on the factors involved in SSRI resistance  and in rTurning to BD, this is a complex illness with heterogeneous clinical presentation. To better understand its biological underpinnings, the iPSC approach focused on clinical phenotypes, such as lithium-responsive patient samples, or on populations with similar genetic profiles, such as BD individuals within a family or larger pedigree. As imaging and postmortem studies suggest a neurodevelopmental etiology of BD, with neuroanatomical abnormalities often present at the first episode, some iPSCs investigations addressed this. In this context, BD-derived iPSC studies support the presence of early pathologic changes, suggested by the differences between the BP and control iPSCs, in genes involved with proliferation, regulation, and differentiation processes ,65. MoreIt has been hypothesized that idiopathic macrocephalic ASD might be generated from early proliferation abnormalities that can lead to long-lasting differentiation defects. Increased NPC proliferation leading to functional defects in neuronal networks  and dysrAlthough iPSC models provide an innovative tool to understand the pathophysiology of neuropsychiatric disorders and perform drug screening in disease-relevant cells, several limitations remain. Studies based on iPSC technology are impacted by variation in reprogramming and neuronal differentiation efficiencies between iPSC lines derived from both the same and different donors. Two main strategies have been developed to face this variation. The first tries to decrease the heterogeneity by selecting patients with shared clinical and biological characteristics or drug responses, with the expectation of inter-individual variation reduction in vitro. The second strategy uses a large cohort of disease-relevant iPSC cell lines to minimize sample variability. This effort is costly and time-consuming, thus iPSC banks were created to provide repositories from which many iPSC lines that are available for a particular disease are stringently checked for quality .One critical issue with iPSC-based disease modeling is the generation of appropriate control iPSCs. Initially, control iPSCs were obtained from healthy, gender-matched family members, but these iPSCs exhibited substantial heterogeneity due to genetic differences. More recently, genetically identical (isogenic) iPSC lines that are created by gene editing approaches from well-characterized healthy control iPSC lines have been employed.A further drawback of iPSC technology refers to the reprogramming process itself, which erases the epigenetic memory of cells. In particular, iPSC-derived neurons are immature and maintain the fetal neuron properties, independently of the age of the initial somatic cell donor . This asThe discovery of direct reprogramming technology has enabled induced neuron (iNs) production, bypassing the iPSC stage. This approach produces a reliable model for late-onset psychiatric disorders, aging-related neurodegenerative diseases, and drug discovery as it does not reset aging information . UnfortuA central limitation of BO is the absent development past the stage of a prenatal brain, probably because the organoids do not elaborate a vascular system. This inadequacy additionally leads to necrotic core formations during tissue development. Therefore, engineering approaches that allow the proper exchange of oxygen, nutrients, and waste products, such as porous scaffolds, recently developed using computer-aided design and 3D printing, have been implemented to address this issue .Another constraint, especially for 3D cultures, is the extensive period involved. Achieving later stages of cell maturation, including astrocyte maturation, takes approximately 9 months. This challenges the feasibility of using these 3D cultures on a very large scale and considerably slows the experimental processes .From a therapeutic perspective, gene-editing techniques could be used to repair the genetic mutations that contribute to disease in an in vivo approach, which involves direct cell modification in the individual, and to repair known causative lesions in patient-derived iPSCs (ex vivo gene therapy). This last intervention requires the culture and modification of patient-derived iPSCs in vitro and the transplantation of the modified cells back into the recipient .For neurodegenerative disorders, such as Parkinson’s disease, iPSC replacement therapies are challenged by the transplantation into an environment where pathogenic mechanisms occur, thereby causing neuronal degeneration and apoptosis. In theory, inserting healthy cells in this type of environment can either have a positive effect due to the neuroprotective factor secretion or result in graft failure. In a recent study, a personalized cell-therapy strategy that used iPSC-derived dopaminergic cells in a patient with Parkinson’s disease lead to a clinical improvement 24 months post-transplantation, a time frame consistent with gradual putamen reinnervation by projections from dopaminergic neurons .A more recent and innovative advancement in iPSC technology is the development of the organ-on-a-chip (OOC) platforms that introduce microfluidic techniques in cell cultures to reproduce the microenvironment through the control of biochemical factors, mechanical forces, and fluid flow. In particular, OOC aims to reflect individual pathophysiological conditions by including blood samples and patient-derived iPSCs and by adjusting biochemical parameters according to personal health data . This stIt is essential to highlight that even the most innovative PP advances should be understood not as a replacement but as an integration of patient assessment. Every therapeutic choice must be inserted into the individual patient’s reality in light of his/her personal and clinical history, complying, to the extent possible, with their own preferences regarding the type of intervention.


Artificial Intelligence (AI) plays an integral role in enhancing the quality of surgical simulation, which is increasingly becoming a popular tool for enriching the training experience of a surgeon. This spans the spectrum from facilitating preoperative planning, to intraoperative visualisation and guidance, ultimately with the aim of improving patient safety. Although arguably still in its early stages of widespread clinical application, AI technology enables personal evaluation and provides personalised feedback in surgical training simulations. Several forms of surgical visualisation technologies currently in use for anatomical education and presurgical assessment rely on different AI algorithms. However, while it is promising to see clinical examples and technological reports attesting to the efficacy of AI-supported surgical simulators, barriers to wide-spread commercialisation of such devices and software remain complex and multifactorial. High implementation and production costs, scarcity of reports evidencing the superiority of such technology, and intrinsic technological limitations remain at the forefront. As AI technology is key to driving the future of surgical simulation, this paper will review the literature delineating its current state, challenges, and prospects. In addition, a consolidated list of FDA/CE approved AI-powered medical devices for surgical simulation is presented, in order to shed light on the existing gap between academic achievements and the universal commercialisation of AI-enabled simulators. We call for further clinical assessment of AI-supported surgical simulators to support novel regulatory body approved devices and usher surgery into a new era of surgical education. In recent years, artificial intelligence (AI) technology has fuelled the advancement of surgical simulators, enhancing their accuracy and capabilities. Surgical simulators are increasingly used in modern medical practice to support preoperative planning and enhance the hands-on experience of training a surgeon. The application of modern AI technology can support simulators in providing personalised feedback to the user, while also automating an immersive surgical experience for visualisation of patient anatomy –5. In thAI can improve surgical training simulators by evaluating performance and providing personalised feedback to the end user . SeveralHowever, like any form of emerging technology, AI-driven performance evaluation and feedback generation remains imperfect with numerous limitations. Lam et al.'s systematic review explored several different ML techniques assessing surgical performance and noted the promising accuracy of ML-based assessment software, while delineating several major challenges and limitations of this technology . One limInterestingly, we note that our review of the FDA/CE list did not identify any approved AI-powered software for appraising and providing feedback in surgical simulation. However, it is conceivable that such software may be commercially available but have not been evaluated through the regulatory process as they do not directly interact with patients .3D visualisation has been a major development in surgical simulation across all surgical specialties ranging from neurosurgery and orthopaedics to maxillofacial, plastics, and general surgery , 13. SucThe most widely accepted technique for creating 3D simulations from 2D images involves convoluted neural network (CNN) algorithms. AI can complement this method by facilitating 3D segmentation and anatomical labeling –21. In a3D-printed simulators have been shown to facilitate preoperative planning, improve surgical outcomes and decrease operation duration ; howeverThe simulation techniques are also integral in surgical training. VSI Holomedicine, for example, provides a platform for both preoperative planning and anatomical education. Furthermore, hyperrealism is an AR concept used in training where artificial objects, such as a silicon replica, are visually enhanced by DL algorithms to simulate a realistic scene of surgery .Current AI frameworks used in surgical simulation have some technological limitations. To begin with, AI-powered feedback platforms could address the challenges experienced with the VOA . For exaAs seen in Additional technical challenges in the visualisation field are attributed to the intrinsic limitations of technological devices,  which is beyond the scope of this review. However, few AI-based solutions are proposed to overcome these challenges. VR-sickness is commonly experienced due to the delay between sensory input and VR. To reduce such latency, CNN models are employed to improve gaze-tracking by pre-rendering subsequent scenes and predicting future frames , 38. AnoAt the moment, the use of AI-based simulation in healthcare comes at a significant financial cost. As traditional practice for both surgical training and pre-operative planning rely on largely inexpensive methods such as near-peer teaching and group discussions, the introduction of AI-based simulators incurs additional costs. The price of such simulators is rarely publicly disclosed and varies greatly depending on quality, capabilities, and use cases. For instance, none of the companies we identified in our FDA/CE database search provided public information on the prices of their product. However, it is well known that the cost of simulator technology is steep. According to some estimates, the price to equip a simulation lab can range anywhere between $100,000 to several millions . The useIt is, therefore, important to understand if the clinical benefit from AI-driven surgical simulators would justify the significant costs associated with their purchase and maintenance. Interestingly, the majority of published research failed to yet report a significant superiority of surgical simulators as compared to traditional methods in the realm of surgical education . For insAt the same time, it is important to explore if the cost of AI-driven surgical simulators can be reduced while maintaining the value they offer in patient care. The concept of “fidelity” refers to how well a surgical simulator represents reality . A rangeIn addition to pursuing lower-fidelity simulators, it is reasonable to expect the price of simulators will be kept within a reasonable range with growing market competition and widespread adoption of this technology. Furthermore, national healthcare services and large healthcare institutions may have the negotiating power to further reduce the prices when supplying their hospitals with AI-driven surgical simulators and related equipment.Presently, a clear overview of all approved AI-based medical devices and algorithms does not exist . Few effTo our knowledge, there are only a handful of AI-powered surgical simulators that are regulatory approved. Nevertheless, we emphasise the need for strict scrutiny of these products to ensure patient safety, transparency, and cyber security , 54. AltMoving forward, global organisations like IMDRF need to corroborate on a consensus on AI regulation since the aforementioned issues are ubiquitous around the globe. As we aim towards universalisation of AI-based surgical simulators, legal and ethical issues regarding accountability and performance transparency of AI-based surgical simulators are crucial components that should be overseen by such governing bodies , 56.Application of AI has the potential to enhance the quality of surgical simulators and expand their capabilities. In this review article, we have discussed the elements of surgical simulation which are enhanced using AI-driven technologies and reviewed the available literature and FDA/CE-approved products. We summarised the current landscape of AI in surgical simulations and provided suggestions for further clinical implementation in


A corollary to this hypothesis is that improving the overall fitness of the cellular mitochondrial collective by forced mitophagy activation might delay age-related cell degeneration and ameliorate age-associated diseases. Experimental systems using overexpression of mitophagy and related factors support this proposition. However, “gene therapy” is not readily translatable to the clinic in this context. Thus, a clinically applicable therapeutic approach to enhance mitophagy is much needed. Recently, Einav Gross and colleagues took a significant step toward achieving this goal by developing small molecule derivatives of spermidine that exhibit mitophagy-enhancing activity in C. elegans and cultured mammalian cells.Mitochondria are central arbiters of cell fate. Mitochondrial respiration produces ATP, the chemical fuel for most biological processes in multicellular organisms. Conversely, mitochondrial respiration that is not properly coupled to ATP synthesis produces mito- and cytotoxic reactive oxygen species (ROS) that can damage cell and organelle DNA, protein and lipid, thereby evoking premature cell senescence or programmed death. The dual role of mitochondria as sustainers of cell life vs engines of cell death requires cells to deploy surveillance and removal systems that identify, isolate and selectively destroy dysfunctional mitochondria that, if retained, would pose a threat to cell wellbeing. The principal process by which overall mitochondrial quality is maintained is through selective culling of dysfunctional and damaged organelles by mitochondrial autophagy, or mitophagy. It is posited that age-related deterioration in mitophagy, and the consequent interruption of mitochondrial quality control, can contribute to adverse aging phenotypes partly because of increased elaboration of mitochondria-derived ROS from improperly retained damaged organellesC. elegans and protect human cells against oxidative damage”, senior author Gross, first author Srivastava, and co-authors build upon previous observations that the aliphatic polyamine spermidine, commonly used in molecular biology laboratories as a DNA binding agent, can delay death by enhancing autophagy. The chemical structure of spermidine is straightforward, consisting of an 8-member aliphatic chain linking amines at each end, with a third amine offset in the middle [In their manuscript, “Distinct designer diamines promote mitophagy, and thereby enhance healthspan in e middle . Srivaste middle , but it C. elegans skeletal muscle and neurons.VL-004 increases mitophagy, measured as mitochondrial delivery to lysosomes and mitochondrial DNA content, in Mitophagy enhancement by the polyamines requires the worm analogs of mammalian Nix/Bnip3 and PINK1 kinase, but not the canonical mitophagy effector, Parkin.Mitophagy activation by VL-004 requires, induces, or is otherwise impacted by altered expression of aging and autophagy genes.VL-004 increases longevity  and improves physical activity  in older worms.Too much mitophagy has adverse consequences, defining a therapeutic window for mitophagy activation.et al. studied primarily in worms.These five major findings, and many others in this highly detailed report, provide fodder for a fresh examination of the relationships between mitochondria and normal senescence or age-related disease. The discussion below uses the mammalian designations for the various factors that Srivastava . The most familiar mitophagy activation pathway is mediated by two juvenile Parkinson’s disease gene products, PINK1 kinase that serves as a trigger for mitophagy in individual dysfunctional mitochondria, and the Parkin ubiquitin ligase that amplifies the mitophagy response at targeted mitochondria. In this selective mitochondrial culling process, PINK1 kinase is protected from proteolytic degradation, enabling its phosphorylation of mitofusin (MFN) 2 and other mitochondrial Parkin receptor proteins that recruit Parkin from its cytosolic storage site to the damaged organelle. Parkin poly-ubiquitination of multiple mitochondrial outer membrane proteins, using PINK1-phosphorylated ubiquitin as the preferred substrate, attracts cellular autophagosomes that engulf the degenerating mitochondrion and transfer it to lysosomes for destruction. This terminal event of mitochondrial transference to lysosomes is the sine qua non of mitophagy, and was the primary metric of mitophagy that Srivastava et al. measured in transgenic worms expressing a mitochondrial-targeted green/red fluorescent protein chimera that changes fluorescence characteristics when mitochondrial proteins are introduced into the acidic environment of the lysosome.Mitophagy is an example of biological multi-tasking, deploying components of the cell starvation autophagy stress-response for the largely homeostatic process of surveilling and removing “mitochondrial trash”  before it interferes with normal cell functioning. Indeed, while Srivastava et al. report that PINK1 kinase was critical for mitophagy enhancement by their novel small mitofusin activating molecules, Parkin was dispensable. Rather, the worm analog of Nix (Bnip3L)/Nip (Bnip3) mitophagy adaptor proteins was required, pointing to mitofusin activation by one of the Parkin-independent pathways. This is consistent with spermidine-derived small molecule mitophagy activating compounds augmenting, in large part, constitutive/homeostatic mitochondrial quality control.Mitochondrial quality control is the canonical role for mitophagy, and likely the mechanism by which its enhancement prevents premature senescence. However, culling defective mitochondria is not the sole purpose of mitophagy, nor is the PINK-Parkin pathway the only pathway to mitophagy. Accumulating evidence in mammalian systems suggests that Parkin-mediated mitophagy may be more important as a stress-induced or developmentally regulated mechanism, and that other paths comprise the major mechanism for homeostatic quality control through “maintenance mitophagy”. Moreover, Parkin-mediated mitophagy can play an essential role during cell-wide mitochondrial replacement, generally accelerating mitochondrial turnover for either quantity control  or provoking a metabolic adaptation in response to an altered environmental context . In most instances, such as Alzheimer’s disease, Huntington’s disease and genetic forms of amyotrophic lateral sclerosis, the underlying causal genetic mutation is neither encoded by the mitochondrial genome nor affects one of the ~1000 nuclear-encoded mitochondrial proteins. . Nevertheless, there is growing interest in developing approaches to correct secondary mitochondrial abnormalities as one component of an ensemble therapy approach to these incurable and largely untreatable diseases. One promising approach attacks the problem of mitochondrial fragmentation, either by inhibiting mitochondrial fission or stimulating mitochondrial fusion. It is intriguing to speculate that these tactics might act synergistically with pharmaceutical activation of mitophagy to correct mitochondrial abnormalities in neurodegenerative diseases.Mitochondrial abnormalities such as fragmentation, loss of inner membrane polarization and increased ROS production have been widely reported in both chronically progressive neurodegenerative diseases and genetic neurological syndromes manifesting an age-dependent phenotypeet al. have taken full advantage of genetic systems to define transcriptional pathways and mitophagy co-factors that mediate enhanced mitophagy, but the actual drug target protein is not known. Information on the VL-004 target and binding characteristics could help direct further chemical modifications to improve potency to the nM range of most orally active pharmaceutical agents.One unanswered question about VL-004 and related small molecule mitophagy activators is “what is the drug target”? Srivastava


The best evidence supports fully integrated palliative care models to ensure biopsychosocial support starting at the diagnosis of a life-limiting or life-threatening condition.2 Although the concepts of longevity and palliative care at first appear to be contradictory, access to palliative care is key to optimising the additional time that longevity affords, particularly for historically excluded populations who have poorer quality-of-life outcomes worldwide. In short, there is no longevity society without equitable palliative care access—and there will be no equity in alleviating serious health-related suffering until we amass the global policy and practice shifts needed to create and sustain inclusive, age-friendly health systems.Achieving a longevity society—one focused on the benefits of living longer and a healthy life expectancy—will require increased adoption of preventive health measures, equitable public health interventions, and the dismantling of ageist structures.3 Looking ahead, serious health-related suffering that could be relieved with palliative care is expected to increase by an estimated 183% by 2060, driven primarily by increased rates of noncommunicable diseases.4 Older people living in low-income and middle-income countries, where the share of the population older than 65 years is predicted to double by 2050,5 will face the compounded burden of serious health-related suffering at the intersection of ageism, poverty, increased prevalence of noncommunicable diseases, and little-to-no palliative care or age-friendly access to health services. However, fully integrated palliative care as a component of universal health coverage2 would be likely to stimulate the needed sociopolitical shifts towards a longevity economy6—one that actively encourages older people to participate in and contribute to society in accordance with their wishes while holistically addressing their needs through readily available, evidence-based symptom management and psychosocial care.People aged 70 years and older account for 40% of patients in need of palliative care worldwide.7 prioritising age-friendly Medication plans, preserving Mentation, and ensuring safe Mobility—all of which assist older people to do and achieve What Matters most in terms of their health goals, values, and preferences. Integrated palliative care will aid in cultivating both clinicians and systems grounded in an age-friendly ethic to ensure person-centred services throughout the serious-illness continuum and especially at the end of life. It is incumbent upon the health-care workforce to develop the communication competencies and community-oriented partnerships that will attune the delivery of palliative care to the cultural needs and experiences of all older people, especially those who are at greater risk of violence, abandonment, and mistreatment through the perpetuation of pervasive discriminatory structures. Structurally vulnerable populations that experience serious health-related suffering alongside trauma , social exclusion, and discrimination have complex palliative needs that must be met across the life course and throughout longevity.8We must garner multi-sector support to develop and sustain age-friendly systems that strategically expand age-friendly health services by considering the “4Ms”:9 Indigenous populations frequently have unmet palliative care needs that exacerbate disparities, such as culturally unsafe care that disregards traditional healing practices, stymies accessibility, and exacerbates financial toxicity.10 Studies have also shown poorer pain and symptom management, lower rates of advance care planning, and lower utilisation of hospices among nursing home residents who identify as a racial or ethnic minority.11 Nursing homes in a number of countries were abandoned by policymakers at the beginning of COVID-19, leading to devastating consequences of social isolation for many residents, particularly for those in marginalised groups—a moral failing that integrated palliative care could help to correct and prevent during future public health crises. Moreover, current health systems are often not responsive to shifting cultural constructs and realities around ageing that could be addressed through palliative care. For example, among immigrant populations within culturally diverse societies, there are changing expectations of intergenerational support in ageing care and the myriad stressors of ageing in a new cultural context.In addition to the consequences of poverty and ageism, many older people have minoritised identities  that render them actively and systematically excluded from accessing equitable palliative care. For instance, sexual and gender minorities might face homophobia, transphobia, social isolation and stigma, disenfranchised grief and bereavement, violence, and criminalisation.Integrated palliative care must be community-based, society-supported, and culturally safe to recentre historically excluded older people . Publicl