Day programs have received significant consideration within psychological literature as part of a continuum of mental health services. With increasing attention on the prevalence of eating disorders in children and adolescents, and the need for early intervention to minimize the costs and burden of the disorder, eating disorder day programs  have begun to emerge around the world. Despite their widespread use, no reviews to date have examined the efficacy of day programs for the treatment of eating disorders in children and adolescents. The current narrative literature review aims to describe and evaluate the efficacy of day programs for children and adolescents. The literature review was conducted according to the PRISMA guidelines and aimed to explore the outcomes and common program elements of day programs to guide clinical practice and service development. The review found variations amongst the day programs related to program elements, measures utilized and outcomes. Overall, the results suggest that day programs for children and adolescents are effective at restoring body weight, reducing eating disorder symptoms and addressing comorbid mental health concerns. Day programs (DP)for children and adolescents with eating disorders are becoming increasingly prevalent around the world. These programs vary in their structure, processes and efficacyThe systematic review of 21 programs revealed day programs as effective in restoring body weight, reducing eating disorder symptoms and addressing comorbid mental health concerns. There is evidence to suggest the maintenance of these gains at 3 and 6 month follow‐upThe review highlights promising models of care, and provides guidance on evidence‐based clinical processes, as well as program evaluations of day programs ABASadaptive behaviour assessment systemADHDattention deficit hyperactivity disorderANanorexia nervosaARFIDavoidant and restrictive food intake disorderBMIbody mass indexBNbulimia nervosaCBT‐Ecognitive behaviour therapy – enhancedCDIchildren’s depression inventoryChEATchildren’s eating attitudes testDBTdialectical behaviour therapyDPfay programsDSMdiagnostic and statistical manualEBWexpected body weightEDeating disordersEDE‐Qeating disorder examination questionnaireEDIeating disorder inventoryEPHPPeffective public health practice projectFBTfamily based treatmentHLChigher levels of careIBWideal body weightMASCMultidimensional Anxiety Scale for ChildrenMDTmultidisciplinary teamMRAOSMorgan and Russel average outcome scoreOSFEDother specified feeding and eating disorderPvAparents versus anorexia scaleRCMASrevised children’s manifest anxiety scaleUSFEDunspecified feeding and eating disorder1Eating disorders (EDs) are complex, prevalent yet treatable mental illnesses, with a high rate of onset in adolescence   is useful for those whose symptoms are too severe to be treated by a traditional outpatient team, but who do not require hospital based, inpatient or a residential treatment Derenne, . At DPs,22.1A review of peer‐reviewed literature was performed by the authors between January 2020 to November 2021 to evaluate the effectiveness of Day Programs (DP) in improving physical  and psychological health  among children and adolescents. In addition to health outcomes, the narrative literature review aimed to identify common program elements of DPs. Given the focus on understanding the efficacy of ED‐DPs, only peer‐reviewed studies were included, and grey literature was not accessed for the review. When further information regarding services and programs were required, the authors directly contacted the authors of reviewed studies requesting further details. The review was performed using the following six databases: PsycInfo, PsycArticles, PubMed, Ebscohost Megafile Ultimate, CINAHL and Psychology and Behavioural Sciences. The search strings utilized are displayed in Table 2.21)Studies published between 2009 and 20212)Inclusion of participants who were diagnosed with any type of EDs using DSM‐IV, DSM‐IV‐TR, or DSM‐5 criteria3)Participants were aged 18 years or younger.4)Collection of quantitative outcomes which must include a measure of body weightIncluded studies met the following criteria:1)All participants of the research were aged 19 years and above.2)Studies that did not assess body weight , Ideal Body Weight (IBW))3)Studies not written in English4)Studies that were not available to view in full text5)Studies that were not peer‐reviewedExcluded studies met the following criteria:The initial database search identified a total of 5437 articles and 50 duplicate articles were removed. Titles and abstracts of the articles were individually and manually screened in reference to the inclusion and exclusion criteria, leaving 71 articles. A manual examination of the full text was conducted in a similar manner, further removing 50 articles from the analysis. The full text of the remaining 21 articles were read to ensure that they met the eligibility requirements  Quality Assessment Tool . One article compared patient outcomes between different levels of care . The following section will present the narrative summary of the ED‐DP services and service outcomes.All studies collected quantitative data and employed a longitudinal study design. One third of studies included follow‐up data post‐discharge , Canada (n = 5), Australia (n =1), Spain (n =1), Germany (n =1), United Kingdom (n = 2) and Italy (n = 2). Several DPs were located on the grounds of pediatric hospitals (n = 10), general psychiatric hospitals (n = 2), and general hospitals  while four studies  did not report the maximum capacity of DP. Three studies reported to have a capacity of up to eight people .All reviewed articles included weight measures assessed by a medical practitioner. All the studies reported an increase in weight by the end of the admission to the DP. Four studies did not conduct inferential statistical analyses to assess changes in weight  included one measure and few studies (n =3) included two measures. Of all reviewed studies, six studies calculated ideal body weight (IBW), and seven studies assessed changes in weight by BMI. Three studies calculated ideal body weight based on MBMI and five studies determined the deviation from ideal body weight by Expected Body Weight (EBW) . Eleven studies used one measure and four studies used two measures to assess ED‐related outcomes. Six studies did not measure any ED‐related outcomes. Measures that were utilized across at least two studies are discussed below.Most of the studies utilized self‐report measures only  and medium to large effect sizes at 6 months follow‐up (d = 0.49 to 0.99). Body Dissatisfaction scale showed statistically significant reduction between pre to 6 months follow‐up only, but not between pre‐ to post‐treatment . Rienecke & Richmond , Revised Children’s Manifest Anxiety Scale , Morgan and Russel Average Outcome Score  and the Multidimensional Anxiety Scale for Children . Of the six studies that utilized the CDI, four reported significant reductions in depressive symptoms at discharge . With several of these interventions utilised currently lacking an evidence base to validate their efficacy, there is a need for ED‐DPs to more rigorously evaluate the efficacy of these novel interventions with children, adolescents and families. It would be useful to identify any unique contributions of these alternate approaches, over and above those gained through evidence‐based treatments like FBT‐informed care or CBT‐E. In addition, as supervised meals provide a parent with an opportunity to learn skills to support their child’s eating behaviours, it may be useful to report the degree of parental involvement  in supervised meal session. Lastly, information about the number of inpatient admissions during an ED‐DP admission was also inconsistently reported. Information about the use of nasogastric feeding during DP admissions may also be of benefit in program evaluations.4With research now pointing to the multi‐organ impact of EDs, ED‐DPs should report on other physical health indicators – including heart rate and blood pressures (Hay et al., The studies reviewed did not consistently report if participants were prescribed psychiatric medication whilst at ED‐DPs. There is much debate on the use of psychopharmacology in EDs with children and adolescents (Flament et al., Most studies reported requiring clients to be medically stable upon ‘stepping down’ from inpatient service to ED‐DP, however many did not specify admission criteria for clients who 'stepped up' from outpatient service to ED‐DP. At present, there is little consensus about how decisions about moving clients across the continuum of ED services are made (Butterfly Foundation, 5The present review concluded, based on the best available research, that ED‐DPs for children and adolescents with EDs are beneficial in promoting physical and psychological recovery. It remains unclear which components of the DPs contribute to recovery. Variations exist between the outcomes or components of ED‐DPs and these can be attributed to the differing clinical and demographic profiles of the clients, issues related to the existing mental health service infrastructure within the country in which the DP was situated, the inclusion of novel interventions, and lack of evidence‐based practices with ED‐DPs. Innovations in the development of mental health services requires further evaluation and validation of the use of a continuum of care and greater consistency in the description of DP models and the children and adolescents accessing these services. The review highlights and supports the use of evidence‐based treatments, such as FBT‐informed care and CBT‐E within ED‐DPs. With increasing scrutiny over the use of health care resources, and the need for validated, evidence‐based practices, robust evaluation and reporting of such mental health services may help with advocating for the early intervention of conditions like EDs in children and adolescents.6


People with type 1 and type 2 diabetes still frequently experience hypoglycaemia, which can be severe, leading to loss of consciousness. This review will examine the cellular consequences of recurrent hypoglycaemia.This review, based on the Dorothy Hodgkin Lecture given at the Diabetes UK 2022 annual symposium by the author, will discuss our current understanding of the mechanisms by which hypoglycaemia is detected and the consequences of recurrent exposure to hypoglycaemia.ß‐cell, namely in their use of glucokinase, KATP channels and AMP‐activated protein kinase. Recurrent exposure to hypoglycaemia results in a series of cellular adaptations that may be designed to increase the resilience of cells to future hypoglycaemia. This review also highlights how hypoglycaemia, as an oxidative stressor, may also exacerbate chronic hyperglycaemia‐induced increases in oxidative stress and inflammation, leading to damage to vulnerable brain regions.Glucose‐responsive cells found in the periphery as well as multiple areas of the brain are organised in a classical sensori‐motor integrative network encompassing peripheral, hindbrain and hypothalamic components. The mechanism used by glucose‐responsive neurons to detect hypoglycaemia parallel those of the classical glucose sensor the pancreatic Impaired awareness of hypoglycaemia follows the adaptation of central glucose‐responsive neurons to repeated hypoglycaemia and may represent a form of memory called habituation. In diabetes, recurrent hypoglycaemia may have tissue consequences as a result of a profound disruption in the cellular response to a hypoglycaemic challenge that increases vulnerability to oxidative damage. In the 50 years since this discovery, we have seen a remarkable evolution in diabetes care, with further refinements of injectable analogues to produce more consistent basal insulin levels as well as faster acting insulin analogues that more closely mimic prandial insulin release. Insulin pump therapy has also advanced and is rapidly progressing, through combination with continuous glucose sensors and control algorithms, towards the introduction of the artificial pancreas into routine clinical practice.ß‐cell insulin production is decreased and α‐cell glucagon secretion increased providing a stimulus to increase hepatic glucose production.Despite these advances, there remain a number of limitations to insulin therapy. Of these, the need to deliver insulin replacement peripherally which results in both systemic hyperinsulinaemia and a failure of insulin to dissipate when glucose levels fall (i.e. insulin release from the subcutaneous depot is not glucose dependent) is a major reason for the increased susceptibility of people with type 1 diabetes to hypoglycaemia. In people without diabetes, when glucose levels fall pancreatic Hypoglycaemia has a recognised morbidity and mortality.2It is now established that most vertebrate species have developed specialised cells within regions of the brain and periphery that are able to respond to changes in the glucose level to which they are exposed leading to the secretion of hormones (e.g. insulin) and/ or neurotransmitters (e.g. glutamate). The cells are linked either through neural pathways or via paracrine/endocrine hormones and acting together provide an integrated system for maintaining glucose homoeostasis.3An example of one of these glucose‐sensing regions is the ventromedial hypothalamus (VMH). In a series of seminal studies it was shown that lesioning or directly microinjecting the non‐metabolisable glucose analogue, 2‐deoxy glucose, into the VMH in rodents stimulated a classical glucose counterregulatory response with rises in systemic levels of glucagon, adrenaline and noradrenaline.4It is now recognised that glucose‐sensing neurons are found within a number of areas of the brain as well as in the periphery. The most well studied of these brain regions is the hypothalamus where glucose‐responsive neurons have been identified in the VMH, arcuate, lateral hypothalamus, paraventricular hypothalamus and supraoptic nucleus. Glucose‐sensing neurons have also documented in brain regions involved in motivation and reward such as the nucleus accumbens, amygdala, paraventricular thalamus, hippocampus and pre‐frontal cortex, and in the hindbrain (e.g. nucleus tractus solitarius) which coordinates functions that are fundamental to survival. As glucose is the primary fuel for all cells, the cardinal feature of glucose‐responsive neurons (as we will discuss below) is their ability to detect changes in glucose and then use that information to produce the appropriate counterregulatory response. As this response involves physiological, symptomatic and behavioural elements it has to be co‐ordinated. Watts and Donovan,5ß‐ and α‐cells, glucose‐excited and glucose‐inhibited neurons respond to higher and lower blood glucose levels respectively. As in the pancreatic ß‐cell, key components of the mechanism through which a change in glucose levels lead to an alteration in neural firing rates should therefore involve glucokinase, sulfonylurea receptor 1 (SUR1) ATP‐sensitive potassium (KATP) channels and AMP‐activated protein kinase (AMPK).ATP channels, depolarising the neurons and increasing their firing rate.Using the ventromedial hypothalamus (VMH) as an exemplar for a glucose‐sensing region, Sherwin proposed that glucose‐sensing neurons operated in a way that appeared to parallel the pancreatic islet.6ATP channelsATP channel blocker glibenclamide suppressed,ATP opener NN414 amplifiedATP channel opener NN414 amplified the counterregulatory response to hypoglycaemia in rodents with or without type 1 diabetes,ATP channel opener, diazoxide significantly amplified the hormonal counterregulatory response to hypoglycaemia.ATP channels in glucose‐responsive neurons, as they do in the pancreatic ß‐cell, are integral to the transduction of the glucose signal.It was established a number of years ago that glucose‐sensing neurons ex vivo contained functional K7ß‐cell is the energy sensor, AMP‐activated protein kinase (AMPK). In a series of studies in rodent models, we were able to demonstrate that pharmacological activation using 5‐aminoimidazole‐4‐carboxamide ribonucleotide (AICAR)Another component of glucose sensing in the pancreatic ß‐ and α‐cells who co‐secrete these neurotransmitters with insulin and glucagon respectively.+/K+ ATPase, K+ channels and nitric oxide synthase (NOS), Ephrins and beta‐adrenergic receptors have been described but are beyond the scope of this review ,w Figure . Readers8The most well‐recognised consequence of recurrent hypoglycaemia for people with type 1 and insulin‐treated type 2 diabetes is the development of impaired awareness of hypoglycaemia which markedly increases the risk of severe hypoglycaemia. The seminal work of Heller established that exposure to hypoglycaemia resulted in a marked suppression of the symptomatic and hormonal counterregulatory responses to a subsequent episode of hypoglycaemia induced the following day.9This whole systems response to recurrent hypoglycaemia is mirrored in ex vivo electrophysiological studies where there is a left‐shift in glucose‐excited neurons so that they do not hyperpolarise until glucose levels fall further.10Alternately, recurrent hypoglycaemia may induce cellular adaptations that allow lactate or ketones to be used as alternate fuels.11More recently, our group have proposed that the whole‐organism response to recurrent hypoglycaemia represents a form of adaptive memory, referred to as ‘habituation’. Habituation is defined as a “reduction of the psychological, behavioural or physiological responses to a stimulus as a result of repeated or prolonged exposure”.Our first approach was to examine whether we could restore counterregulatory responses to hypoglycaemia in animals that had been exposed to recurrent hypoglycaemia by introducing a ‘dishabituatory’ stimulus. Dishabituation is the introduction of a novel, usually strong stimulus, to a habituated response which will result in at least temporary restoration of the habituated response.In summary, it is apparent that recurrent hypoglycaemia leads to a series of adaptations that may be direct or indirect in specialised glucose‐sensing cells throughout the body, the net effect of which is to reduce the responsiveness of these cells to subsequent hypoglycaemia (a ‘left‐shift’ in the counterregulatory response to subsequent hypoglycaemia). The culmination of these changes in many different brain regions is the development of impaired awareness of hypoglycaemia in people with diabetes. This is considered an adaptive response that may develop through habituation and is likely to represent a mechanism to ensure the cells remain resilient to future periods of low glucose. This may also be considered ‘maladaptive’ in type 1 diabetes, largely because the inability to switch off exogenous insulin that is being released continuously from a subcutaneous depot, and because of the hypoglycaemia‐specific defect in alpha cell‐derived glucagon release, means that hypoglycaemia is occurring in ‘unphysiological’ context and so can become quite profound Figure . As a co12More recently it has also been recognised that recurrent hypoglycaemia in diabetes may have long‐term consequences particularly on brain function. Epidemiological research on the long‐term impact of hypoglycaemia on the brain is limited, largely because most studies are only able to examine the association between severe hypoglycaemia and cognitive performance or brain structure. Meta‐analyses report that a history of severe hypoglycaemia is associated with a small negative effect on a number of different cognitive domains, especially with early‐onset type 1 diabetes.The brain is vulnerable to hypoglycaemia due to its high metabolic demand, reliance on glucose as a fuel, minimal fuel stores and reduced capacity to access alternate fuels because of systemic hyperinsulinaemia.Chronic hyperglycaemia,13ß‐cell with key components being glucokinase, sulfonylurea receptor 1 (SUR1) ATP‐sensitive potassium (KATP) channels and AMP‐activated protein kinase (AMPK). The research programmes are also translational, seeking to understand why recurrent hypoglycaemia leads to suppression of the normal physiological counterregulatory response. Here current evidence supports the idea that this is as a result of a series of cellular adaptations, presumably designed to better preserve cell integrity during future hypoglycaemia. This understanding offers the opportunity of novel approaches to preventing or restoring defective counterregulation through interventions such as HIT. Finally, a literature is emerging that recurrent hypoglycaemia, when associated with increased glycaemic variability, may have longer term consequences in some tissues such as the brain. Oxidative damage as a result if an impaired cellular stress response to hypoglycaemia, particularly when there is a marked glucose excursion on recovery, may accelerate tissue aging. This highlights the importance not just of hypoglycaemia avoidance, but of achieving recommended glycaemic targets and careful management of glucose recovery from a hypoglycaemic event.In this review I have provided an outline of research performed in my own laboratory as well as a number of others that has sought to understand the mechanisms that underpin the physiological response to hypoglycaemia. Some of this has been discovery research, seeking to understand the basic biology of glucose sensing by the brain. To that extent, it is now broadly accepted that discrete populations of glucose‐responsive neurons are present within peripheral, hindbrain, hypothalamic and other brain regions that are organised in a classical sensori‐motor integrative network. Within these regions, we find glucose‐excited and glucose‐inhibited neurons that respond to high and low blood glucose levels, respectively and use signalling mechanism that are broadly similar to those found in the pancreatic The work of the McCrimmon Laboratory has been supported by grants from the JDRF, Diabetes UK, Tenovus Scotland, the Medical Research Council, the Wellcome Trust, the EU Innovative Medicines Initiative and the Helmsley Trust.


Chronic limb‐threatening ischemia (CLTI) with severe below‐the‐ankle (BTA) lesions is often difficult to revascularize with endovascular treatment (EVT) and surgical treatment. We present a case of successful limb salvage using percutaneous deep venous arterialization (pDVA) in a patient with CLTI whose BTA lesion reconstruction failed. A 57‐year‐old man with diabetes mellitus and end‐stage renal failure on maintenance hemodialysis was referred to our hospital because of gangrene in the second and third toes of his left foot. EVT was repeated for the anterior tibial artery, posterior tibial artery (PTA), dorsal foot artery, and plantar artery lesions; however, revascularization below the ankle was unsuccessful. As the infection had spread to the sole of the foot, below‐the‐knee amputation was indicated, but the patient refused. Therefore, we performed pDVA on the left PTA simultaneously with a Lisfranc amputation. An arteriovenous fistula was created at the ankle joint using a Venous Arterialization Simplified Technique and a guidewire was inserted into the plantar vein. Balloon dilatation from PTA to the plantar vein was performed to complete the pDVA. Although repeated EVT was required to maintain blood flow in the pDVA, skin grafting was performed 3 months after the pDVA, the wound completely healed, and he was discharged 6 months after the DVA. The pDVA can be an option for limb salvage in patients with no‐option CLTI who are confronted by imminent amputation. Clinical course of wound healing following percutaneous deep venous arterialization. Angiography revealed severe stenosis and occluded lesions with heavy calcification of the left below‐the‐knee (BTK) and BTA Figure . Repeate3After Lisfranc amputation Figure , a 4.5FrThe occluded PTA was dilated to the level of the ankle joint with a 2.5 × 40 mm JADE balloon , and a guide extension catheter  was introduced distal to the PTA. Surgical cannulation of the posterior tibial vein (PTV) in the ankle was unsuccessful. Therefore, the PTV was punctured as distal as possible at the ankle joint under extravascular ultrasound guidance, and a slender 4Fr sheath  was antegradely inserted. A snare  was introduced from the PTV to the point where it overlapped the inflated balloon at the distal PTA Figure , and a 24Necrotic tissue on the amputation surface increased up to 2 weeks after the pDVA Figure . Thereaf5Patients with CLTI frequently have BTK lesions, for which revascularization is important to achieve blood flow to the foot wound. Patients with CLTI undergoing hemodialysis are often complicated by severe BTA lesions. The clinical benefit of BTK angioplasty in patients undergoing hemodialysis is limited owing to severe BTA lesions, with hemodynamic improvement achieved in only half of the patients.6Percutaneous DVA with balloon angioplasty without the LimFlow system was effective in limb salvage after repeat pedal angioplasty failed in patients with CLTI on hemodialysis.Tomonari Takagi: Conceptualization; investigation; visualization; writing – original draft. Akira Miyamoto: Supervision; writing – review and editing. Norihiko Ohura: Writing – review and editing. Yamauchi Yasutaka: Writing – review and editing.This study was not supported by any funding.The authors declare that they have no competing interests.The study was performed in accordance with the Declaration of Helsinki and approved by the ethics committee of our center.Written informed consent was obtained from this patient.All the materials are original, and we did not need permission to reproduce material from other sources.


This study aims to analyze the impact of age and sex on botulinum neurotoxin (BoNT‐A) dosing and outcomes in adductor spasmodic dysphonia (AdSD).A database review of all spasmodic dysphonia patients treated with BoNT from 1989 to 2018 at the Mayo Clinic in Arizona was performed. Only patients who had received ≥4 injections of BoNT‐A for AdSD were included. Patients were divided into two cohorts to analyze age, with an age of first treatment cutoff of 60 years. Patients were divided into male and female cohorts to analyze sex.p = 0.048). The mean maximal benefit was similar ; however, the mean length of benefit was significantly shorter in younger patients . The mean BoNT‐A dose was significantly higher in the female cohort . The mean maximal benefit was similar , as was the mean length of benefit .The final analysis included 398 patients. The mean dose of BoNT‐A per treatment was significantly higher in the younger cohort  and experienced a shorter length of benefit, but the maximal benefit achieved was similar to the older cohort. Females received higher doses of BoNT‐A with other outcome metrics similar to males.What this study adds: This study represents the most highly powered publication to date addressing the impact of age and sex on the nature and efficacy of BoNT‐A treatment for adductor spasmodic dysphonia. Its findings can assist physicians in patient counselling and BoNT‐A dose selection. Spasmodic dysphonia (SD) is a task‐specific focal laryngeal dystonia.Based on the significant symptom response of blepharospasm to intermittent injections of botulinum neurotoxin (BoNT‐A), Blitzer et al. performed the first laryngeal injection of BoNT‐A for SD in 1984.Limited data are presented in the literature regarding the impact of age and gender on outcomes of BoNT‐A treatment in AdSD. This study aims to analyze the impact of age and sex on outcomes in AdSD treated with BoNT‐A. It was hypothesized that these groups would be similar in baseline characteristics and outcomes with BoNT‐A treatment, with outcome measures including mean BoNT‐A dose, mean self‐perception of maximal benefit, mean perceived length of benefit, mean time between injections, mean breathiness duration, and mean duration of dysphagia to liquids.A retrospective database review of all SD patients treated with BoNT‐A from 1989 to 2018 at the Mayo Clinic in Arizona (Phoenix) was performed. This study was approved by the Mayo Clinic Institutional Review Board (10‐007839).All patients were evaluated by an otolaryngologist, a movement disorder neurologist, and a speech‐language pathologist. Evaluation was performed by the same otolaryngologist over the entire study period and the same neurologist over 28 years. Medical history, laryngeal examination, voice evaluation, and screening neurological evaluation were performed on all patients. The patient's medical history and auditory‐perceptual evaluation provided the information to make the diagnosis for most patients. Fiberoptic transnasal laryngoscopy influenced the diagnosis in some cases.Patients diagnosed with AdSD, with or without vocal tremor, were included in this study. Patients with these diagnoses who also manifested vocal characteristics of muscle tension dysphonia were included. Patients with abductor SD, mixed SD, primary muscle tension dysphonia, isolated vocal tremor, dysarthria, Tourette's syndrome, and other voice disorders were excluded from the analysis.Only patients who had received ≥4 injections of BoNT‐A were included. Injections are performed using electromyography (EMG) guidance with the subcutaneous injection of local anesthetic. BoNT‐A is injected into each thyroarytenoid muscle using a 37‐mm, 27‐guage Teflon‐coated monopolar EMG injection needle. A 100‐unit vial of BoNT‐A diluted with preservative‐free saline to a concentration of two units per 0.1 ml is prepared for each patient. At our institution, patients are initiated at a dose of 1.2 units bilaterally with subsequent dose titration guided by patient response and preference. Some patients convert to unilateral injection. We elected to exclude the first two injections from the analysis. The third dose received is the first included in the analysis with a subsequent injection required to collect outcome data. To analyze the role of age, patients were divided into two cohorts: those with a first treatment aged 60 or younger and those with a first treatment over the age of 60. Patients who had previously received treatment at another institution were placed in the cohort based on the age of their first outside injection and their first two injections at our institution were excluded. To analyze the role of sex, patients were divided into two cohorts: male and female.Details recorded include sex, age of symptom onset, the time between first injection and last injection, number of injection sessions, presence of vocal tremor, presence of a coexisting movement disorder, and family history of SD or other dystonias.t‐test or Wilcoxon rank sum test when applicable. A p‐value < 0.05 was used to define statistical significance. Means are presented with the standard deviation in Tables Outcomes compared included mean BoNT‐A dose, mean self‐perception of maximal benefit (patients are asked to attribute a percentage to the maximum benefit received from the previous injection), mean perceived length of benefit from the previous injection (in weeks), mean time between injections, mean breathiness duration (patients are asked to provide a duration of breathiness in days or weeks), and mean duration of dysphagia to liquids (patients are asked to provide a duration of dysphagia to liquids in days or weeks). Data were collected at the patient's next injection appointment using a standardized questionnaire that remained unchanged over 30 years. Dose refers to the total amount administered in a treatment session . Individual patient averages were calculated and the averages of these were analyzed. This was performed to prevent analysis from being skewed by patients who have received many treatments (up to 80). Linear regression was used to adjust for sex or age, coexistent vocal tremor, and other movement disorders. Analysis was conducted using advanced statistical software and a two‐sample Our database search identified 795 patients. The final analysis included 398 patients Figure .p < 0.01). The length of follow‐up was similar (median = 6 years) but younger patients received a higher median number of treatments . Older patients were more likely to have coexistent vocal tremor (p < 0.01) or other movement disorders (p = 0.03). There was no difference in the family history of SD or other dystonias. Documentation of age of dysphonia onset was present in slightly more than half of patients, with means of 40 years and 62 years in the younger and older cohorts, respectively. Table Of the included patients, 199 received their first injection ≤60 years old (50%) and 199 received their first injection after their 61st birthday (50%). Demographic details are displayed in Table p = 0.048). The mean maximal benefit was similar ; however, the mean length of benefit was significantly shorter in younger patients . Length of Posttreatment breathiness did not differ, with a mean of 16 days in both cohorts. Length of posttreatment dysphagia to liquids did not statistically significantly differ . Table The mean BoNT‐A dose was significantly higher in the younger cohort . Female patients were more likely to exhibit a coexistent vocal tremor . Cohorts were similar regarding the length of follow‐up, the number of treatments, additional movement disorders, and family history. The mean BoNT‐A dose was significantly higher in the female cohort . The mean maximal benefit was similar (69% vs. 75% (p = 0.58), as was mean length of benefit . Length of posttreatment breathiness and posttreatment dysphagia to liquids were similar. Table Of the included patients, 320 (80%) were female and 78 (20%) were male. Demographic details are displayed in Table Though widely accepted, BoNT‐A treatment for AdSD is not standardized; because no clear guidelines exist, protocols in BoNT‐A treatment of patients with SD vary among physicians. A survey of practicing laryngologists in the United States found that 70 participants collectively reported treating >4000 patients with SD annually.This study aimed to analyze the influence of both age and sex on BoNT‐A dosage and treatment outcomes in AdSD. For the analysis of age, patients were initially divided into three cohorts . The demographics, clinical characteristics, and outcomes between patients <50 years old and 50–60 years old were similar, and therefore these groups were combined to result in two cohorts that were evenly sized by chance. Data pertaining to the age of dysphonia onset was unavailable for almost half of the patients in the study which limited its use as a metric for analysis. However, available data suggest that patients allocated to the first injection aged 60 years or younger cohort had significantly earlier disease onset compared to the older cohort.The impact of age on BoNT‐A treatment for AdSD has previously been studied. In 2009, Vasconcelos et al. retrospectively reviewed treatment outcomes in 155 patients who had received more than five treatments of BoNT‐A for AdSD.Vasconcelos et al. and Lerner et al. both studied the significance of sex along with age.This study represents the most highly powered publication to date addressing the impact of age and sex on the nature and efficacy of BoNT‐A treatment for AdSD. Mayo Clinic in Arizona has evaluated and treated over 700 patients diagnosed with AdSD for more than 25 years with a consistent treatment team. The practices employed in our institution are similar to those reported popular by practicing laryngologists, suggesting the results presented are widely applicable to the practices of physicians in the United States and patient outcomes could be expected to reflect those at other centers employing similar techniques.Significant limitations exist in this study. Data analyzed were collected prospectively over 25 years and analyzed retrospectively, presenting the opportunity for occult errors and biases to exist. The age of dysphonia onset was missing for nearly half of the patients which prevented its meaningful use in the study. Patients in the older cohort may have previously been treated in centers other than ours and attributed to the incorrect cohort despite this being considered in the analysis. The outcome metrics used were subjective and have not been validated. Importantly, data were collected at the patient's follow‐up appointment which introduced the possibility for significant recall bias. In both the analysis of age and sex, the cohorts had significant differences in their demographics and characteristics, including in the prevalence of vocal tremor. A retrospective study by Patel et al. found that patients with AdSD with vocal tremor achieved fewer good voice days following treatment with AdSD compared to patients with AdSD alone.Patients 60 years of age or younger at the first injection of BoNT‐A for the treatment of AdSD tended to have a higher mean dose of BoNT‐A per treatment compared to patients older than 60 years at the first injection. This younger cohort experienced a shorter mean length of benefit but the mean maximal benefit achieved by BoNT‐A treatment was similar. Females in this study received significantly higher doses of BoNT‐A. Other than differing dosing, our male and female cohorts were similar regarding the maximal benefit of treatment, length of benefit, and posttreatment breathiness and dysphagia.Richard Heyes contributed to the study design and conception, data collection, analysis, drafting, and approval of the final manuscript. Charles H. Adler contributed to the study design and conception, data collection, analysis, and approval of the final manuscript. Nan Zhang contributed to the study design, data analysis, and approval of the final manuscript. David G. Lott contributed to the study design and conception, and approval of the final manuscript. Stephen F. Bansberg contributed to the study design and conception, data collection, analysis, drafting, and approval of the final manuscript.The authors declare no conflict of interest.The above manuscript is the authors' own original work, which has not been previously published and is not in submission elsewhere. The paper reflects the authors' own research and analysis in a truthful and complete manner and properly credits the meaningful contributions of coauthors and coresearchers.


Veneer crowns can be used in anterior endodontically‐treated teeth with light occlusal force and enamel substrate consideration as a more conservative approach instead of conventional all ceramic crowns.All‐ceramic anterior crowns and veneers have been used widely in dentistry with high clinical success rate. The development of new reinforced ceramics in recent years has led to more use of extended defect‐oriented preparation designs, that is, extended veneers, instead of full crown preparations which are less invasive. A veneer crown is simply a veneer that covers the entire tooth. The preparation preserves remaining enamel and uses a conservative preparation design. Its indication should be carefully raised taking into consideration various factors. The preparation design is crucial to ensure longevity of such restoration. The balance is between sufficient preparation for the material thickness and adequate strength against occlusal load and the enamel preservation. A 24‐year‐old man referred to the restorative department of the Dentistry School of Tehran University of Medical Sciences complaining from his poor esthetics in the maxillary incisors. In clinical and radiographic evaluation, he had open bite, composite discoloration due to corrosion of the pre‐fabricated posts in all four incisors, a periapical lesion in tooth 21 and under‐filled root canal therapy in tooth 22. All four posts and composite restorations were removed and teeth 21 and 22 were retreated. Although the amount of remaining tooth tissue was low, it had enough enamel thickness, especially in the buccal area. Taking into consideration this mixed enamel and dentin substrate, endodontics access, esthetics needs and canine guidance occlusion with no parafunction history, bonded lithium disilicate veneer crowns were selected to restore the maxillary incisors. A 12‐month follow‐up showed promising clinical  and radiographic  outcomes. A case of veneer crowns in anterior teeth. In the past, due to its brittleness, ceramic was generally fused to a metal substrate to increase fracture resistance, and its indication was limited to full‐coverage crowns. However, the metal base compromises the esthetics.The reliable bond to enamel achieved with the adhesive technique has greatly impacted preparation design, resulting in significant preservation of tooth structure. Increased preservation of enamel promotes a superior bond over dentin and improved support of the ceramic restoration. The combination of highly translucent porcelains and composite cements has facilitated the clinical use of the adhesive technique and launched a new era of restorative treatment options.All‐ceramic anterior crowns and veneers have been used widely in dentistry with high clinical success rate.The silicate and zirconia‐based ceramics are the most common materials for the all‐ceramic restorations.Silicate‐base ceramics include feldspathic porcelain and glass ceramics. Feldspathic porcelain has high translucency like natural teeth and excellent retention after etching with hydrofluoric acid but it has low mechanical properties due to its high glass contents. Therefore, feldspathic laminate veneers gain their strength from bonding to stiff enamel.Although enough tooth preparation is necessary to provide material thickness and esthetics, it compromises the strength of the underlying tooth structure. The balance between these items will be different in each case. So, in each patient the tooth preparation should be planned.One of the most common treatments for anterior endodontically‐treated teeth with moderate to severe destruction is conventional crown with metal post and core. Although, the common process of crown preparation and the gray color of metal posts leads to a significant loss of the remaining enamel and dentin structure to provide adequate strength and color of the restorations.Numerous publications have focused on preparations for all‐ceramic crowns in anterior endodontically‐treated teeth. However, there are few studies on extended veneers or veneer crowns  in these teeth.2It was about a 24‐year‐old man who was referred to the restorative department of the Dentistry School of Tehran University of Medical Sciences. He complained from his poor esthetics in the anterior region of maxillary teeth. At the age of 10, the patient had a dental trauma that led to the fracture of four anterior teeth and their root canal therapies (RCT). He had no medical history or systemic problems and was not currently taking any medication. Due to his left axillary central incisor dental abscess, he was first referred to the endodontics department. In clinical evaluation, he had open bite with mild protrusion of central incisors, canine guidance occlusion without any parafunction history, and composite discoloration due to corrosion of the pre‐fabricated posts in all four incisors. Therefore, all four posts and composite restorations were removed and the teeth were evaluated for remained caries and the need for re‐endo. In radiographic evaluation, he had a periapical lesion in tooth 21 and under‐filled root canal therapy in tooth 22  according to the manufacturer's instructions.For this purpose, first the gutta percha of each incisor's canal was removed to the extent of two‐thirds of the root length from the orifice by using peeso reamers (Mani Peeso Reamers 32 mm). Each canal was then cleaned with alcohol and the largest prefabricated glass fiber posts  that go through the length of preparations were selected. The incisors teeth were isolated and each canal was dried with absorbent paper points (Meta Biomed). The fiber posts were cleaned and silanized (Bis‐Silane™). The dual cure self‐adhesive resin cement (Embrace™ WetBond™ Resin Cement) was directly applied on the treated fiber posts surfaces and into the canal and pulp chamber 5 s according to the manufacturer's instructions. The fiber posts were protected from light until the cementation procedure. The fiber posts were immediately placed into the final position and stabilized. They were light‐cured for 40 s by a 1500 mW/cm2 curing light output (woodpecker ILED plus). Then the foundation restorations were completed with A2 shade composite resin (Tokuyama Estelite Sigma Quick).The teeth were etched with 37% phosphoric acid  for 15 s. The acid was then removed with water spray for 20 s and the teeth were carefully dried. The dental adhesive bond  applied on the teeth, gently dried and cured for 20 s by a 1500 mW/cmThe preparation of the veneer crowns design was similar to all ceramic crowns except that the buccal reduction is 0.5 mm and the lingual reduction is 0.5–1 mm.3 shade in cervical, A2 shade in coronal part and medium translucency in incisal edge. Lithium disilicate glass ceramic can be used for the fabrication of monolithic or layered restorations in the anterior and posterior region. Due to its natural‐looking tooth coloring, good light‐optical properties and mechanical features, this material produces successful results. Depending on the clinical structure of the tooth, the restorations may be bonded (with resin cement) or cemented. The bonded approach allowing a more conservative preparation.Once the preparation was finished Figure , retractWhen the prosthetic pieces were received, marginal fit and color were checked intraorally. Occlusal contacts were also verified: with static and dynamic occlusion. Retractor cords  were placed in gingival sulcus to optimize the bonding quality. The outer surfaces of the prosthetic pieces were protected by polydimethylsiloxane  and then carefully treated by hydrofluoric acid 4%  for 20 s. After rinsing, the ceramic residues and remineralized salts were eliminated by applying 37% phosphoric acid  for 20 s, followed by rinsing, air drying and ultrasonic cleaning in distilled water for 5 min. After air drying, one layer of silane, a chemical coupling agent,  was applied with a microbrush to the inner surfaces of the restorations and left for 1 min. Intraorally, the prepared teeth well isolated and were etched with 37% phosphoric acid  for 30 s on enamel and 15 s on dentin, then rinsed and air dried. An adhesive  was carefully applied according to the manufacturers' instructions. After that, the clear shade light cure resin cement  was applied on the inner surfaces and the restorations were placed carefully on the prepared teeth. Light curing was performed at the facial, incisal, and palatal surfaces for 90 s at each surface. Next, the gingival cord was removed using dental pincers, and excess resin cement was removed and chipped off with a no. 12 surgical blade.Although there was 1 mm overbite, there was no contacts on palatal and incisal surfaces of maxillary incisors during lateral mandible movements due to canine guidance occlusion. The final result is shown in Figure 3Several factors can influence the anterior teeth treatment plan. Some of them are patient‐related like caries activity, age and loads during static and/or dynamic occlusion. The other factor that influences treatment plan is the remaining tooth tissue.The studies showed that using of a composite resin associated with the glass fiber posts, presented similar fracture distribution to the sound teeth because it results in a unique bonded complex providing favorable stress distribution. In these studies, teeth restored with direct composite resin without posts showed more root fractures in the cervical third and the proximal deformation than the same restorative technique associated with glass fiber posts. This information is important for clinicians as it clarifies that a glass fiber post may be indicated when a large amount of the tooth structure is removed.All‐ceramic crowns have been used widely in dentistry with similar clinical success rate to metal‐ceramic crowns. Their survival rate in the anterior region after 11 years is 98.9%.All‐ceramic crowns are superior to veneers in nonvital teeth due to increased strength, retention, masking ability, and longevity. However, endodontically treated abutment teeth have less stability by removing large amount of tooth structure.A veneer crown is simply a veneer that covers the entire tooth. It can be used only in selected cases, with (1) esthetics of primary importance. (2) Mixed enamel and dentinal substrate. (3) Minimal or no parafunction. The preparation preserves remaining enamel and uses a conservative preparation design. The most common indication is for a peg‐shaped lateral incisor. Another indication is a tooth with good enamel support, large proximal restorations, and endodontic access.Veneer crowns should be avoided when there is insufficient enamel, parafunction, unsuitable anatomical presentation of teeth and poor dental care. The risk factors for ceramic veneers and veneer crowns failure are bonding onto pre‐existing composites restorations, placement by an inexperienced operator, using veneers to restore teeth with large areas of exposed dentin and insufficient tooth structure.All‐ceramic crowns provide better esthetic result with less tooth structure reduction and higher biocompatibility when compared to a metal‐ceramic crown. But in these restorations tooth preparation must be precise because sharp angles concentrate stress under the restoration, which lead to micro‐crack formation and fracture. Bonding of the silicate base ceramics with resin cements and phase transformation in zirconia reduce these problems.A new method of restoring endodontically treated teeth is endocrowns. Govare et al stated that endocrowns are a reliable alternative to post‐retained crowns for posterior teeth. However, a right preparation design and a meticulous adhesion protocol are necessary. They also stated that lithium disilicate glass–ceramic and nanofilled composite have been used more in endocrowns. The lack of data on endocrowns in anterior teeth and the varied results in different studies mean that an indication for endocrowns in anterior teeth cannot yet be stated.In recent years, zirconia ceramics have changed in microstructure and composition to achieve esthetically acceptable translucency without significant reduction in fracture resistance. Translucent zirconia is an esthetic material and can be used for many clinical situations including anterior and posterior monolithic crowns and fixed prostheses, veneers and ultrathin veneers.Limits of the present clinical presentation include the absence of an adequate population sample, the replicability of the technique and the limited follow up. In addition, the success of restorations is highly dependent on the patient's occlusal force pattern. Our patient did not have heavy occlusal forces and had slight overbite. Results may vary in other patients with heavier occlusal forces.4The veneer crown is a reliable esthetic solution for teeth, which have all the advantages of ceramic veneers. Its indication should be carefully raised taking into consideration various factors. The preparation design is crucial to ensure longevity of such restoration. The balance is between the sufficient preparation for the material thickness and adequate strength against occlusal load and the enamel preservation.It is common to use conventional all ceramic crowns instead of veneer crowns or extended ceramic veneers to restore esthetics and function in endodontically treated teeth. However, veneer crowns can be used in anterior endodontically treated teeth with light occlusal force and enamel substrate consideration as a more conservative approach.Mandana Karimi: Methodology; writing – original draft. Sedigheh Sadat HashemiKamangar: Methodology; supervision. Shakiba Farahani: Writing – original draft; writing – review and editing.The authors have no conflict of interest to declare.Written informed consent was obtained from the patient to publish this report in accordance with the journal's patient consent policy.


Osteoarthritis is a progressive and heterogeneous joint disease with complex pathogenesis. The various phenotypes associated with each patient suggest that better subgrouping of tissues associated with genotypes in different phases of osteoarthritis may provide new insights into the onset and progression of the disease. Recently, single‐cell RNA sequencing was used to describe osteoarthritis pathogenesis on a high‐resolution view surpassing traditional technologies. Herein, this review summarizes the microstructural changes in articular cartilage, meniscus, synovium and subchondral bone that are mainly due to crosstalk amongst chondrocytes, osteoblasts, fibroblasts and endothelial cells during osteoarthritis progression. Next, we focus on the promising targets discovered by single‐cell RNA sequencing and its potential applications in target drugs and tissue engineering. Additionally, the limited amount of research on the evaluation of bone‐related biomaterials is reviewed. Based on the pre‐clinical findings, we elaborate on the potential clinical values of single‐cell RNA sequencing for the therapeutic strategies of osteoarthritis. Finally, a perspective on the future development of patient‐centred medicine for osteoarthritis therapy combining other single‐cell multi‐omics technologies is discussed. This review will provide new insights into osteoarthritis pathogenesis on a cellular level and the field of applications of single‐cell RNA sequencing in personalized therapeutics for osteoarthritis in the future. Schematic of the applications of scRNA‐seq in OA. Single‐cell RNA sequencing could elucidate the molecular mechanisms in osteoarthritis and identify potential targets to design targeted therapies. scRNA‐seq can also evaluate the safety and effectiveness of therapeutics by clarifying the cell population changes in the surrounding microenvironment. In the future, combining multiple single‐cell multiomics technologies will further pave the way for personalized treatment. Risk factors mainly include age , followed by the female sex, obesity, genetics and joint injury.OA is usually characterized by pathological features such as cartilage destruction, subchondral bone remodelling, synovitis, and meniscus degeneration, which ultimately leads to joint deformity.Since the invention of single‐cell RNA sequencing technology (scRNA‐seq), some defects can be filled.In a word, the diagnosis of OA is usually established late in the disease process, therefore, too late to expect much help from drugs to modify OA.In this paper, we reviewed recent research on the applications of scRNA‐seq in OA for the first time, briefly introducing the general principles of scRNA‐seq. Then, the findings in different structural tissues highlight the discovery of potential pathogenesis and targets in OA. Finally, we discussed and nominated that, combined with other single‐cell omics techniques, scRNA‐seq will contribute to the deeper interpretation of mechanisms and evaluate promising personalized therapeutics for OA in the future.2Before scRNA‐seq was widely used, it is rather challenging to identify cell surface markers that are neither unknown with prior knowledge of genes or proteins nor characterized by multiparametric flow‐activated cell sorting (FACS) analysis or large‐scale cytometry.As a prerequisite to generating robust data sets, sample preparation should be optimized depending on sets of characteristics of samples, for example, tissue or cell types and culture conditions, such as 3D organoid models.Instrumental methods to isolate single cells vary in the number of cells (high‐throughput or low‐throughput) and the selection (biased or unbiased).Microfluidic technology with precise fluid control gradually gained popularity due to its low sample consumption and cost. Recently, microfluidic technologies had been wildly applied in the latest methods in upgrading single‐cell technologies. μCB‐seq (Microfluidic Cell Barcoding and Sequencing) combining high‐resolution imaging system enabled to preload of primers inside addressable reaction chambers of a microfluidic device to improve gene detection sensitivity.Largely determined by scRNA‐seq protocols, the sequencing depth is a significant experimental parameter to be considered when separating complex tissue at hand, as well as experimental objectives. These protocols have strengths and weaknesses in linear amplification, length coverage, low copy RNA species detection, high throughputs, and cost reduction. Six commonly used methods to synthesize cDNA from single‐cell mRNA/RNA: cell expression by linear amplification and sequencing 2 (CEL‐seq2), Drop‐seq, massively parallel RNA single‐cell sequencing (MARS‐seq), SCRB‐seq, Smart‐seq and Smart‐seq2.CEL‐seq2 utilized linear strand‐specific transcript amplification mainly at 3′ ends reducing mRNA molecule counting biases with unique molecular identifiers (UMIs), a short unique sequence.Single cell RNA barcoding and sequencing (SCRB‐seq) is a high throughput protocol with 12,000 cells per time and also includes UMIs. A significant advancement was made with Smart‐seq that full‐length cDNA synthesis could complete about 40% of transcripts in 2012, followed by Smart‐seq2 which was updated later in 2013.Drop‐seq and InDrop‐seq are similar methods in the throughput. The main difference between them is that Drop‐seq uses reagent‐containing beads while the latter uses reagent‐carrying hydrogel microspheres.Four key steps are typically involved in the data analysis process: data cleaning and normalization, dimension reduction, clustering and post‐clustering examination. Dimension reduction is performed after reading count normalization to avoid ‘the curse of dimensionality’. Principal component analysis is an essential method for unsupervised linear dimensionality reduction but consumes a long computation time for large‐scale scRNA‐seq datasets. A more effective strategy is that iteratively conduct the data analysis process with different numbers of principal components (PCs). For example, using populations relating to chondrocytes, osteoblasts, or other already delineated cell populations as ‘landmarks’ to aid in internal control.Cell‐type identification is a dominant feature of scRNA‐seq. Recently, many algorithms have been developed and assessed to attain cell clustering and cell‐type identification quickly and accurately.Available technologies for scRNA‐seq have unique strengths and weaknesses. Researchers are supposed to consider the scale of the experiment, the sensitivity of each method and the biological question to be answered, before the research begins.3The data of scRNA‐seq opens the door to answering the biological questions in OA: what cell types exist within high molecular heterogeneous diseased tissues? How to do cellular state switches work to manifest OA physiologic derangements? How do gene expression correlations regulate OA progression?3.1Articular cartilage is the most important part of the knee joint and is vulnerable to the outside changes. Articular cartilage destruction due to injury or mechanical stimuli,Differentiated from BMSC, chondrocytes were found to be heterogeneous in the previous studies,Chondrocyte hypertrophy and matrix lesions will give rise to the occurrence of cartilage destruction in OA.The cartilage ECM further destroyed its structure and deteriorated its biomechanical properties and metabolic homeostasis in late‐stage OA.Especially in the damaged areas of chondrocyte ECM, chondrocyte subclusters may destroy cartilage homeostasis to accelerate OA progression. Lv et al. analysed the damaged area of human articular cartilage tissues and found a subcluster related to ferroptosis in cartilage damage of OA. The stressed chondrocytes (StrCs) with high frequency in the damaged area of OA, preferentially expressed HSPB1 (heat shock protein B1).Although lacking intrinsic reparative ability, articular cartilage still contains some cell populations that might be involved in the maintenance of homeostasis. Ji et al. found that HomCs with highly expressed genes of human circadian clock rhythm markers and favourable genes against OA, showed the ability to control the circadian clock in OA progression.3.2The structural changes in synovium are mainly associated with the symptoms, such as pain and synovitis, during OA progression. Synovitis encompasses a range of abnormalities, such as fibrosis, infiltration of macrophages and synovial lining hyperplasia.Synovial tissue exhibited hypertrophy and hyperplasia in the end‐stage OA with different phenotypes in patient‐reported pain sites and synovitis may appear before the cartilage degeneration in the early stage OA. With distinct SF subsets in the early‐ and late‐stage OA, apparently, patterns of synovitis are closely related to these SFs subsets, which has been identified the heterogeneous of SF in rheumatoid arthritis (RA).The ‘non‐painful’ early‐stage OA SFs  subclusters with higher expression of early‐stage OA, no pain (gelsolin) relate to synovial hyperplasia. However, GSN was downregulated in end‐stage OA subclusters, suggesting that protective mechanisms against inflammation and oxidative damage are gradually lost during OA progression. Using the scRNA‐seq data of SFs from two OA patients, Wu et al. explored that Fibronectin1 (FN1),With a pro‐inflammatory phenotype, subclusters of synovial macrophages may also accumulate synovial inflammation and pain in OA. Figure  Bone marSynovitis was found to be related to obesity, which was responsible for specific inflammatory phenotypes by bulk RNA‐seq. Owing to obesity, loading became an important hallmark to elevate OA, resulting in the secretion of pro‐inflammatory cytokine. Croft et al. discovered that SFs subsets in obese OA patients were differentially impacted by synovitis. ‘Activated fibroblasts’ and ‘immune cell recruiters’ notably maintained ECM and the activation of leukocytes respectively. The ‘immune cell recruiters’ subset with high expression of CHI3L1 mediates inflammation in obese OA patients. These subsets are localized in the sublining and lining layers of OA synovium tissue which can be distinguished by FOS ,3.3Meniscus was divided into three regions because of the density of blood vessels . Cell types in meniscus include chondrocyte‐like morphology cells and fibroblast‐like cells, and the inner region contains chondrocyte‐like morphology cells whilst the outer region contains fibroblast‐like cells. When meniscus degenerates in OA progression, the peripheral vessels fade and the fibroblast‐like cells populated, followed by collagen fiber network reorganized and the chondrocyte‐like morphology cells differentiated into fibroblast‐like cells.Meniscus degeneration is an important risk factor for knee OA and their relationship is complex.Sun et al. demonstrated the existence of progenitor cells–fibrochondrocyte progenitors (FCPs) with CD146 specifically highly expressed in healthy meniscus and degenerated meniscus progenitors (DegPs) marked with CD318 in OA meniscus.Among the meniscus zones, the red zone is rich in blood vessels. Vascularization of this region is the most active while the other two zones are avascular to a different degree.3.4Beneath the hyaline cartilage and cement line, subchondral bone consists of the subchondral bone plate and subchondral bone trabecula. During OA progression, abnormal subchondral bone remodelling and angiogenesis in subchondral bone also contribute to cartilage destruction. The inhibition of osteoclast activity and remodelling processes associated with angiogenesis are the main reasons for the pathogenic mechanisms. Therefore, the microstructural and histopathological changes in subchondral bone are due to changes in the interactions amongst the multiple cell populations such as osteocytes, osteoblasts (OBs), osteoclasts, endothelial cells and so on.Accumulating studies perceived genetic networks to characterize the pathophysiologic progress of OA.Our group used scRNA‐seq to further identify the cell–cell communication networks in the subchondral bone.We also demonstrated three phenotypes of OBs that comprehensively depicted their subtypes of them. Phenotypes changes from EnOBs  to StOBs , and finally the spatial mineralization phenotypes MinOBs  that relate to abnormal osteogenesis. EnOBs are tightly correlated with OBs proliferation and StOBs are associated with collagen fibril organization, assisted by OPN and fibronectin while MinOBs directly relate to ECM mineralization as the terminal state of bone formation leading to osteosclerosis in the end stage of OA.scRNA‐seq helps to delineate the impact of changes in the patterning of various cells on pathological structures during OA progression, linking previous perceptions together to reveal consensual mechanisms. However, applications of scRNA‐seq in bone biology are just the beginning and recent research merely elucidated the potential cell subcluster targets, still lacking a strong indication of characterizations both in vitro and in vivo.4Based on the mechanisms elucidated in the previous context, scRNA‐seq has been conducive to discovering potential therapeutic targets, contributing new insights to the development of new therapeutics. Conventional omics analysis of joint tissues was used to identify candidate biomarkers or potential targets to elucidate the mechanisms of OA. However, previous analyses have merely focused on the associations of particular molecules or molecular changes with OA rate of progression, so far, rather than on the discovery of phenotypes.To date, scRNA‐seq has provided new targets to regulate specific cell populations retarding OA progression and verified the feasibility from an unbiased perspective the same time, which supports to translation these findings into useful tools in clinical care. Figure  For exam4.1Restoration of bone microenvironment integrating with seed cells is a promising approach to drive the development of bioactivity bone biomaterials. The seed cells used most widely in tissue engineering are chondrocytes and MSCs (or progenitors), facilitating to repair and regenerate of the damaged cartilage that restores the functional properties of the impaired joint.The cartilage ECM could not only withstand mechanical loads but also sense changes in the microenvironment during OA progression and transmit signals to the chondrocytes.A tiny switch of cell states through regulating many signalling pathways may affect the feature of different OA phenotypes. HTC‐A was important in cartilage development while HomCs regulated cell cycle and metabolic changes. Both cell clusters may provide new implications for constructing and developing effective OA drug delivery systems. The molecular processes underlying both homeostatic and pathologic circadian chondrocyte biology may not be uniform.4.2FCP (CD146+) as progenitors also shows the ability in meniscus repair to prevent OA in vivo. With regional differential chondrocyte phenotypes, chondrocyte‐like cells in the meniscus may gradually differentiate into fibroblast‐like cells in the degeneration. Meniscus tears typically do not spontaneously heal, therefore, to repair the avascular zones, recruiting and fibrochondrocytic differentiation of the resident cells is essential to restoring meniscus biomechanical function.4.3Different endothelial cell plays different roles in the heterogeneous microenvironment in joint tissues of OA. The meniscus is more susceptible to catabolic stimuli than articular cartilage, thereby, repairing the complex anisotropic phenotype concerning blood vessel development to disrupt OA development. ALPN has been regarded as a target in ECs subclusters of meniscus cells to antiapoptotic maintaining vascular activity in the red zone. On the other hand, pre‐ECs and EC are connected with pathological angiogenesis coupling with aberrant osteogenesis to accelerate OA progression in the subchondral bone.4.4The local low‐grade inflammation in OA is considered a potential therapeutic target as epidemiological studies have reported an association between synovitis, OA pain and structural damage.Developing treatments for OA remains challenging.5scRNA‐seq is gradually used to evaluate the effectiveness or toxicity of therapeutics by discovering the microenvironment changes after accepting the objective treatments. Indeed, based on the mechanisms and targets revealed by scRNA‐seq to design therapy strategies, as a return, it can also reevaluate the most suitable to conduct in the pre‐clinical trials. Figure  PatientsOne promising single‐cell phenotyping tool with a massive scale  for capturing phenotypic heterogeneity entails continuously observed over time microscopically.Joint replacement surgery, the most common treatment method for OA therapy, is mainly focused on the late stage of the disease progression. The limited therapeutics hinder the available clinical options for patients. Meanwhile, there are growing requirements from the increasing occurrence of musculoskeletal disease in the aging population, demanding high‐quality bone grafts or tissue‐engineered biomaterials. However, the obstacle in the development of bioactive biomaterials and clinical applications is that the biological processes involved in osteoconduction capability lack a comprehensive explanation for further use. Recent developments in smart biomaterials give a chance to guide cell behaviours and responses when building the complex bone microenvironment. Thereby, detailed landscapes at a high resolution provided by scRNA‐seq will accelerate bone tissue engineering development.As mentioned before, interpatient heterogeneity in OA has an extraordinary impact on the devising of pharmacological strategies or tissue‐engineering treatments. Thus, evaluating the effectiveness of therapeutics amongst different patients allow for precise treatments of OA. To further understand how CPCs contribute to disease interpatient heterogeneity and compensate for the uncovered scRNA‐seq data in the previous study,Mapping genotypes to phenotypes is one of the diagnosis functions of scRNA‐seq and precisely typing different patients contributes to personalize therapy with specialized drug responses. A scRNA‐seq study confirmed the variable clinical symptoms in different OA patients.To sum up, scRNA‐seq is expected to be a fundamental tool for translating safe and effective therapeutics for each patient into clinical reality rather than ‘one rule applied to all patients’. A powerful platform constructed by thousands of scRNA‐seq data will provide a roadmap to pinpoint drug reactions/biomaterial perturbations on the damaged tissues of each OA patient subset to establish personalized medicine strategies for OA.6Investigating the disease progression with one‐dimensionally technology only provides a snapshot of the complex mechanisms. Consistent with a transformative new approach of NGS technologies, analysing genomics, epigenomics, spatial, proteomics and metabolomics at the cellular level provides an opportunity for scRNA‐seq to jointly learn across multiple types of data.In epigenomics, advances in single‐cell chromatin accessibility technologies have enhanced our ability to document cellular phenotypic variation. A robust method‐single‐cell accessible chromatin using sequencing (scATAC‐seq) revealing the landscape of cellular DNA regulatory variation that is systematically associated with specific trans‐factors and cis‐elements began to use in the regulation of hematopoiesisIn proteomics, high‐throughput and high‐content methods for protein analyses, are mainly mass spectrometry (MS). In metabolite analysis, matrix‐assisted laser desorption ionization (MALDI)‐MS has also been performed to characterize peptides. MALDI‐MS is the most applicable method in the rheumatology field and combined with imaging further allows the detection of peptides and proteins in situ.Spatial omics emerged as a new frontier of rapid identification of cell types and spatial distributions.The integrated use of single‐cell technologies in cancer research has undoubtedly revolutionized the relationships across cellular modalities and holistic understanding of the biological characteristics of tumours.+++++hi fibroblast populations were related to different cell states.Without the frontier methods, traditional multi‐omics were used to identify genes in biological processes of osteophyte development such as ERK1 and ERK2 cascade between chondrocytes from osteophytes and articular cartilage tissue from OA patients.In summary, generation of single‐cell multi‐omics datasets has revealed many new insights into the biological process of musculoskeletal disease, but translating these big datasets into advanced diagnostic tools and feasible therapeutics is still a long way to put them into realized.7The booming combinatorial strategies and advances in sequencing platform such as microfluidics with low costs have empowered single‐cell sequencing technology to an exciting level. However, there are still many challenges involved in computational data, collating data analysis to biological progress and implementation in the realm of precision medicine during a single experiment.One of the challenges in interpreting the data is assembling them into a patient‐centric context or a clinical problem. Collectively, multiple and iterative layers of individual patient complexity would be added when longitudinally evaluating biological samples. However, individual categorized treatments in precision medicine will be developed aided by computational and machine learning approaches. Then, considering the applications in recent research, underpowered studies with low sample sizes may miss true signals and are susceptible to producing false‐positive results. On the other hand, lacking a ‘gold‐standard’ data analysis pipeline miring reproducibility is a common problem in multi‐omics technologies. Building global data sharing repositories such as biobanks However, in bone biology, scRNA‐seq still has much shortness remaining to be solved. Bone tissue samples are hard to obtain not to mention the isolation problems, thereby, the best single‐cell protocols with high throughput per cell in case of missing important cell clusters. However, with the complex mix of heterogeneous cells, deciphering the sequencing data without the interference of MSCs needs to be consistent with the aim of the study. Currently, studies using scRNA‐seq to elucidate the mechanisms or find potential targets with the bioinformatic tools lack a common sense that the identified cell population should be recorded and even applied or characterized in later studies. This will help to build the whole cell atlas for the OA pathogenesis and classification of patients with discovered biomarkers by scRNA‐seq. The applications in evaluating the therapeutics are increasingly developing, and shortened in characterization in vivo and in vitro. With single‐cell multi‐omics technologies, better treatment for each patient will finally be invented.In conclusion, we reviewed the recent applications of scRNA‐seq in OA. scRNA‐seq can not only reveal the mechanisms that different cells phenotype in damaged structures relating to OA progression, but also discovered targets through data analysis for better therapeutics construction. With increasingly applied in different problem solving, scRNA‐seq will contribute more resources to re‐examine the OA pathophysiology comprehensively and evaluate the safety and effectiveness of developing therapeutics in pre‐clinical research for OA.Yuyuan Gu and Yan Hu conceived, wrote, revised the manuscript and made the figure and table. Hao Zhang and Sicheng Wang revised the manuscript. Ke Xu and Jiacan Su reviewed, revised and edited the manuscript. All authors read and approved the final manuscript.The authors declare no potential conflicts of interest.