The ability of B cells to generate antibodies and provide long-lived protective immunity is the cornerstone of vaccination and has contributed to the success of modern medicine. The nine different antibody subclasses produced by humans have effector functions that differ according to antigen type and route of exposure. Expression of the appropriate isotype is critical for effective humoral immunity, and it is becoming clear that subclass specificity is to some extent reflected at the cellular level. Understanding the mechanisms that govern the induction, expansion, and maintenance of B cells expressing different antibody subclasses informs the strategic manipulation of responses to benefit human health. This article provides an overview of the mechanisms by which the different human antibody subclasses regulate immunity, presents an update on how antibody subclass expression is regulated at the cellular level and highlights key areas for future research. Expression of the appropriate antibody isotype is critical for effective humoral immunity. Subclass specificity is to some extent reflected at the cellular level and better understanding of the mechanisms that govern the induction, expansion, and maintenance of B cells expressing different antibody subclasses could be valuable to for developing B cell targeting treatments.  The incredible diversity of antibody responses allows our immune system to react to an unlimited number of antigens with high specificity and is central to protective immunity. As well as protecting us from pathogens, antibodies maintain homeostasis by regulating commensal organisms at mucosal surfaces and facilitating the clearance of apoptotic cells. All of this is achieved through a broad range of effector functions that can take place throughout the human body. In addition to neutralization, which is entirely dependent on the variable region, these effector functions depend on the Fc portion of antibodies interacting with cell surface receptors. Localized patterns of subclass expression and receptor distribution regulate antibody responses appropriately for site-specific threats. This specialization is most evident in selective antibody deficiencies, where the absence of an individual subclass can increase susceptibility to specific pathogens. Similarly, dysregulation of subclass expression can promote disease, as is the case in allergies and various autoimmune pathologies. The selection of antibody class is strongly influenced by the site of antigen exposure and the context in which B cell activation occurs. In turn, the selection of antibody class can modify B cell fate and function.B cells are generated in the bone marrow continuously throughout life, emerging as antigen-naïve B cells that express membrane IgM as a B cell receptor. Alternative splicing allows the transcription of IgD with an identical specificity that is co-expressed alongside membrane IgM. Mature naïve IgM+IgD+ B cells circulate through the follicles of secondary lymphoid tissues until they encounter antigen. Multi-valent antigens and/or signaling from other co-receptors such as toll-like receptors can drive a T-cell independent response. Otherwise, B cells will migrate to the T:B border of the follicle where T-dependent responses are initiated. Activation of B cells results in a burst of proliferation during which class switch recombination (CSR) can occur and germinal centre responses are initiated. During germinal centre responses, B cells further diversify their antigen receptors through somatic hypermutation and are ultimately selected to enter the memory pool as either plasma cells or memory B cells. Plasma cells migrate to survival niches from where they can secrete antibody continuously for a lifetime . Memory This review will highlight the key roles different antibody subclasses play in specific aspects of immunity, the mechanisms that regulate their distribution and production, as well as discussing the evidence for intrinsic cellular properties based on antibody isotype. The importance of regulating antibody production is highlighted by the clinical phenotypes of selective deficiencies, but also when responses are dysregulated such as in allergy and autoimmune conditions. Better understanding of how antibody responses are regulated at the cellular level will present new opportunities for targeting B cells associated with antibody-mediated disease.All antibodies are made up of two identical heavy and light chains. The antigen binding fragment (Fab) interacts with the antigen, confers specificity, and is unique to each individual B cell clone. In humans, the crystallizable fragment (Fc) can be one of five isotypes , each wiHaemophilus influenzae but also targets commensals and soluble dietary proteins [IgD is the second least abundant antibody class in human serum after IgE and has a relatively short half-life. Despite being scarce in circulation, IgD plays an underappreciated role in mucosal immunity. IgD-producing plasma cells are derived from nasopharynx-associated lymphoid tissue and have restricted dissemination in the aerodigestive tract . IgD derproteins , 7. IgD proteins . Despiteproteins , pointin+ CD27+ CD43+ CD70− cells that are functionally equivalent to murine B1 cells produce natural antibodies. However, unlike mice the main source of human natural antibodies is marginal zone B cells. IgM comprises around 10% of serum antibodies but also has a key role in mucosal immunity, making up 10–20% of the plasma cell population in the human terminal ileum [IgM plays a significant role in initiating immune responses and pathogen clearance. This isotype is produced early after antigen encounter by short-lived extrafollicular plasma cells, but can also be generated by affinity-matured long-lived plasma cells . The penal ileum . Polymeral ileum . Selectial ileum . IgM-conal ileum . Pentameal ileum . These cUnlike most mammals, humans (and some primates) have two subclasses of IgA that differ in hinge structure  and pattAs the most abundant class of antibody in serum, IgG plays a central role in systemic immunity and is the primary effector antibody raised in response to inflammation. The four IgG subclasses differ in hinge structure and CH2 domains , resultiApproximately half of all serum antibodies are IgG1, which is a potent activator of complement and binds with high affinity to activating Fcγ receptors, thus making it a key player in humoral immunity. Given this abundance, specific IgG1 deficiency results in overall hypogammaglobulinemia and is associated with generalized susceptibility to infection . IgG1 isIgG2 makes up approximately 16% of total serum antibodies and almost all of the fraction that binds specifically to bacterial polysaccharides . IgG2 doAt just 4% of IgG in serum, IgG3 is far less abundant than IgG1 but appears very rapidly following viral infections, thus playing a key role in early immune defense (reviewed in ). IgG3 hIgG4 antibodies are rarely induced in response to infections but instead arise in response to chronic antigen exposure, typically allergens and other non-infectious protein antigens. IgG4 is regarded as a non-inflammatory subclass since it does not bind to C1q and has a relatively low affinity for activating Fcγ receptors. The hinge of IgG4 has intra-chain bonds and displays weaker interactions between CH3 domains compared with other IgG subclasses . This reDespite being the least abundant antibody class in human serum and displaying the shortest half-life, IgE has a significant and highly prevalent impact on human health as the central mediator of allergic disease. The potent effector functions of monomeric IgE are a consequence of high affinity for FcεRI expressed on granulocytes, which increases its half-life to several weeks . IgE is H promoters have cytokine-responsive elements that differ between subclasses, hence the efficiency of CSR directly correlates with germline transcription [Class switching is a tightly regulated, irreversible process that exchanges the constant region gene by deletional recombination . It remacription . For exacription . In addicription . Unlike cription . Consequcription . Class scription )Following activation and interaction with cognate T cells, some B cells expand within extrafollicular foci to give rise to short-lived plasma cells and extrafollicular memory B cells, whereas others form germinal centres. The germinal centre response involves clonal expansion and affinity-based selection of antigen-specific B cells, followed by their differentiation into either long-lived memory B cells or plasma cells. The fate of germinal centre B cells is intricately linked to the B cell receptor, and affinity for antigen plays a key role in B cell fate selection. Higher affinity binding has been linked to preferential differentiation towards plasma cells, either due to cell-intrinsic mechanisms linked with BCR signaling or because of improved antigen capture and increased competitiveness for T cell help .Although germinal centre B cells have higher thresholds for activation than naïve B cells , those tThe short-lived plasma cells generated in extrafollicular responses secrete antibodies that help combat acute infections, but long-lived plasma cells (LLPC) derived from germinal centres are the primary source of high-affinity, class-switched serum antibodies that underpins protective immunity. Human LLPC can survive for decades and continually secrete high concentrations of antibody . Plasma Along with plasma cells, memory B cells are an essential component of long-lived protective immunity, generating rapid responses during secondary antigen exposure. Memory B cells express a BCR at the cell surface and display extensive heterogeneity which has been linked to isotype. This is most evident when comparing switched and unswitched memory B cells. Although unswitched cells comprise a significant portion of extrafollicular-derived cells, transcriptional profiling of switched versus unswitched populations has revealed marked functional diversity despite equivalent levels of somatic hypermutation (a marker of GC experience) . CrucialDifferent subsets of memory B-cell display functional heterogeneity that influences their ability to expand, migrate, and differentiate the following activation. These include variable expression of surface receptors and secreted factors that modulate responses to antigens, influence their localisation, and alter interactions with other cell types in the local environment. For example, increased expression of CXCR5 on IgG3+ memory B cells was reported in patients with multiple sclerosis . In contMost analyses of memory B cell populations focus on circulating populations, but there is increasing appreciation for the role of tissue-resident memory B cells in immune surveillance (reviewed in ). As higMemory B cells retain the ability to class switch, which has major implications for secondary responses. Antibody repertoire analysis of peripheral blood B cells has revealed that while the majority of switch events occur from IgM to IgG1 and IgA1, distinct hierarchies of class switching exist that cannot be explained by the relative abundance of individual subclasses . SwitchiCollectively, the different antibody subclasses provide protective immunity and maintain homeostasis. While there are clear overlaps in effector function, each isotype performs specialist roles in terms of timing, distribution, and specificity of a response, as highlighted by the clinical phenotypes of selective antibody deficiency. The regulation of subclass production is therefore critical for the generation of an appropriate antibody response to specific pathogens. The contribution of antibodies to disease also continues to gain attention with the discovery of new roles in conditions not previously thought to be immune-mediated, such as fibromyalgia  and card


CLCN7 gene leading to impaired bone resorption. Autosomal recessive osteopetrosis (ARO) is a more severe form and is frequently accompanied by additional morbidities. We report an adult male presenting with classical clinical and radiological features of ADOII. Genetic analyses showed no amino-acid-converting mutation in CLCN7 but an apparent haploinsufficiency and suppression of CLCN7 mRNA levels in peripheral blood mononuclear cells. Next generation sequencing revealed low-frequency intronic homozygous variations in CLCN7, suggesting recessive inheritance. In silico analysis of an intronic duplication c.595-120_595-86dup revealed additional binding sites for Serine- and Arginine-rich Splicing Factors (SRSF), which is predicted to impair CLCN7 expression. Quantitative backscattered electron imaging and histomorphometric analyses revealed bone tissue and material abnormalities. Giant osteoclasts were present and additionally to lamellar bone, and abundant woven bone and mineralized cartilage were observed, together with increased frequency and thickness of cement lines. Bone mineralization density distribution (BMDD) analysis revealed markedly increased average mineral content of the dense bone (CaMean T-score + 10.1) and frequency of bone with highest mineral content (CaHigh T-score + 19.6), suggesting continued mineral accumulation and lack of bone remodelling. Osteocyte lacunae sections (OLS) characteristics were unremarkable except for an unusually circular shape. Together, our findings suggest that the reduced expression of CLCN7 mRNA in osteoclasts, and possibly also osteocytes, causes poorly remodelled bone with abnormal bone matrix with high mineral content. This together with the lack of adequate bone repair mechanisms makes the material brittle and prone to fracture. While the skeletal phenotype and medical history were suggestive of ADOII, genetic analysis revealed that this is a possible mild case of ARO due to deep intronic mutation.Osteopetrosis is a heterogeneous group of rare hereditary diseases characterized by increased bone mass of poor quality. Autosomal-dominant osteopetrosis type II (ADOII) is most often caused by mutation of the The online version contains supplementary material available at 10.1007/s00223-022-00988-8. CLCN7; OMIM #602727) .FERMT3 [Also, we confirmed that the exonic sequences of all genes known to cause osteopetrosis or high bone mass contained no low-frequency variants that might contribute to the phenotype, with the exception of an amino-acid substitution Arg215Gln in FERMT3 , the genFERMT3 . Since aFERMT3 , it is pFERMT3  and “posFERMT3  algorithCLCN7 in this patient might be attributed to the abovementioned homozygous deep intronic duplication, which might alter SRSF-binding sites; however, a precise mechanism for this and the mechanism for the development of CLCN7 haploinsufficiency were not fully elucidated in the current study.Reduced transcription of The conclusion from genetic analysis is that the proband phenotype was the result of autosomal recessive inheritance and should, therefore, be classified as ARO rather than ADOII. The homozygous intronic duplication may only cause the suppression of the level of CLCN7, which would explain the relatively mild phenotype comparable to that expected of ARO. Heterozygous inheritance of one or more of these intronic mutations may explain the relatively unremarkable medical histories of the proband’s mother, younger sister and nephew.CLCN7 gene result in reduced bone resorption by osteoclasts and perhaps disturb the coupling between osteoclastic resorption and bone formation by osteoblasts [In general, defects in the eoblasts . At an oeoblasts . A conseeoblasts , togetheeoblasts .Furthermore, we observed an abnormally high number and increased thickness of cement lines. In general, cement lines are considered to be the first material deposited onto the resorption surface by mononuclear cells . This reCLCN7 deficiency could also affect mineral embedded osteocytes, the predominant cell type in bone [CLCN7 in mouse and human osteocytes and have shown that it is upregulated in an in vitro model of perilacunar remodelling [CLCN7 expression in contrast might hamper the ability of the osteocyte to acidify its surrounding matrix, which is needed during osteocytic osteolysis [In addition to affecting osteoclast activity,  in bone –41. We hodelling , a proceodelling , 42. Theodelling , 44, whiodelling , 42, 45.teolysis . Thus, iteolysis , or an ateolysis .At the material level, the iliac crest bone biopsy from our patient in general contained greatly increased calcium concentrations and higher heterogeneity of mineralization compared to reference data from healthy adult individuals. This is in line with the high calcium concentrations in CLCN7-dependent osteopetrosis reported by others . At leasCLCN7 leading to a remarkably increased bone mass. His iliac crest bone consists of lamellar bone but also of inclusion of mineralized cartilage and primary woven bone with abnormally thick and highly mineralized cement lines. These histologic abnormalities are potentially the result of reduced expression of CLCN7 in osteoclasts and possibly osteocytes, causing low rates of bone resorption and the lack of internal bone repair, which is the likely cause of his brittle bone, with reduced fracture resistance.In conclusion, we describe an ARO patient with an ADOII-like phenotype, without an amino-acid-converting mutation but with intronic mutations in Supplementary file1 (PPTX 384 kb)Below is the link to the electronic supplementary material.


Among cerebrovascular disease, stroke is a life-threatening neurological event and a main cause of serious long-term disability, with relevant healthcare and economic burden. Treatment of stroke is time dependent and organised integrated stroke care enables quick and effective responses to reduce stroke-related death and disability. This study aimed at evaluating the amount of hospital discharge to transitional care facilities for stroke patients to support integrated care models in the city of Pavia .In 2017 in Pavia, Fondazione IRCCS Policlinico San Matteo started a partnership with Fondazione Mondino to build a specific stroke pathway, becoming a leading centre for stroke treatment. We conducted a retrospective chart review (RCR) of patient-centred data to quantify the volume of discharge for stroke patients. Two trained public health residents reviewed medical records with stroke admission diagnosis during 2021, analysing onset , ward, treatment and discharge types .Our RCR found 669 patients with a stroke diagnosis treated at San Matteo hospital in 2021, the vast majority of which were admitted to the neurology ward . The recanalization rate was 32% (150 on 464 ischemic stroke patients). Regarding the discharge type, 299 patients (45%) were sent home, while 297 patients (44%) needed transfer to rehabilitation or long-term care facilities. About 8% (52 patients) of the overall sample died in hospital.Our analysis showed that, while most stroke patients were discharged and sent home, more than two-third need to be transferred to continue to get the right healthcare from the right professional. Transitional care facilities should receive the greatest consideration by systems and providers seeking to implement care models to reduce residual neurological disabilities for stroke patients.• A fast and accessible emergency chain is essential to reduce residual neurological disabilities and the related healthcare and economic burden in stroke patients.• Extending the stroke path model to other time-dependent diseases is increasingly high-priority to shape a strong and resilient healthcare system, ensuring qualified health coverage.


Alcohol-Associated Liver Disease–From Pathogenesis to Treatment” proposed by the Frontiers in Physiology has attracted a total of 20 articles on preclinical and clinical studies that were covered in 16 original research manuscripts, 2 brief research reports, 1 review and 1 systematic review. Overall, these articles provide a better understanding of the molecular mechanism(s) that mediate the development and progression of alcohol-induced liver pathology, as well as identifying new biomarkers, therapeutic targets and promising novel therapeutic agents to prevent, manage, or reverse the disease progression. In this editorial, we as guest editors provide a summary of all the articles published in this Research Topic.The Topic “Valchin et al. deliberated on the role of the molecular circadian clock disruption in liver pathology. They showed that alcohol consumption disrupts 24 h rhythms in mRNA levels of multiple clock and lipid metabolism genes in the liver causing small droplet macrosteatosis. Using liver specific knockouts, these authors concluded that the liver clock is important for maintaining temporal control of hepatic lipid metabolism and suggested that circadian clock disruption may be an important risk factor in the pathogenesis of ALD. Wang et al. using a rat model demonstrated that sustained sleep deprivation caused an elevation of liver enzymes and plasma lipids levels which was associated with hyper activation of the sympathetic nervous system. The authors further showed that insomnia-induced hepatic steatosis could be abrogated with pharmacological ablation of the hepatic sympathetic nerves. Furthermore, the treatment of insomnia with estazolam inhibited sympathetic activation and reduced hepatic steatosis. The article by Dou et al. highlighted the key role of long non-coding RNAs (lncRNAs) in the development of ALD pathogenesis. The authors revealed that the five lncRNAs downregulated in a mouse model could serve as novel biomarkers of ALD. The authors further demonstrated that the most downregulated lncRNA, lnc_1700023H06Rik, played a pivotal role in lipid deposition. A manuscript by Li et al. showed that excessive drinking can induce miR-378b, which disrupts insulin signaling by targeting insulin receptor and p110α genes to downregulate their protein expression. These authors implicate miR-378b upregulation in the pathogenesis of ALD-associated hepatic insulin resistance.There were four original papers that described pathogenic mechanism of disease progression. An article by Zheng et al. demonstrated that treatment with Lactobacillus reuteri (L. reuteri) reversed the phenotype of ethanol-induced hepatitis and metabolic disorders in a mouse model of ALD. Their findings provided evidence that L. reuteri might serve as a new therapeutic strategy for ALD. Gao et al. presented a brief research report on the effect of 2-week of abstinence on the functional capacity of gut microbiota in patients with alcohol use disorder. Using a shotgun metagenomic sequencing, they identified different microbial functional responses to alcohol abstinence indicating a link between functional alterations of the gut microbiota and steatosis induced by alcohol consumption. These findings clearly lay foundation for a potential role of specific probiotic intake or fecal microbiota transplantation as an approach to treat alcohol use disorder. The next two articles demonstrated the importance of maintaining copper homeostasis and IFN-γ signaling to combat alcohol toxicity at the gut-liver axis, leading to a better control of the pathogenesis upon alcohol intoxication. While Lin et al. documented that copper maintains gut barrier integrity, possibly by regulating intestinal HIF-1α gene expression and oxidative stress, Yue et al. demonstrated that constitutive expression of IFN-γ is instrumental in maintaining intestinal STAT signaling, innate immune responses and gut microbial symbiosis. Yue et al. further suggested that IFN-γ-based interventions, such as IL-18 treatment, could be considered as a way of boosting intestinal epithelial innate immunity to halt systemic pathogen-associated molecular patterns translocation and may also be one approach for preventing the development of ALD. Tang et al. utilized a synthetic retinoid, fenretinide, and showed that it can be beneficial in preventing ALD, potentially through modulation of the intestinal barrier function, endotoxemia, and toll-like receptor 4-mediated inflammatory signaling. These authors in their brief research report suggested that pre-clinical investigations of this synthetic retinoid should be conducted as a potential pharmacological treatment for ALD.There were several articles on the dysregulation of the gut-liver axis in ALD. Using both animal and clinical studies, the authors offered interventions to prevent the development of ALD. Waleed et al. on alcoholic hepatitis patients revealed a higher frequency of liver disease complications, hospital-acquired infections and longer duration of hospitalization in non-academic as compared to academic centers, despite similar hospitalization-related costs. The authors recommended conducting large prospective studies to validate these findings, examine mechanisms of infections in ALD patients and develop strategies to reduce hospital-acquired infections. A systematic review and meta-analysis by Hegyi et al. in patients with cirrhosis due to NASH showed that sarcopenic obesity is associated with two folds higher mortality at short and long-term follow up after receiving liver transplantation. This study suggested that the inclusion of body composition assessment before liver transplant may help to plan a more individualized nutritional treatment, physiotherapy, and postoperative care as a basis for improving the post-transplant outcomes of high risk obese patients with NASH who also have sarcopenia. Another clinical study by Riva et al. examined immunoregulatory checkpoint receptors in ALD patients vs. healthy controls. The authors reported that soluble T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) was a dominant plasma checkpoint receptor in ALD patients, and this correlated with the disease severity. Increased TIM3 was also associated with elevated levels of soluble TIM3 ligands and membrane-TIM3 expression on immune cells. Importantly soluble TIM3 blocked the TIM3-ligand synapse to improve antibacterial immunity representing an innovative immune-based supportive treatment to rescue anti-bacterial defences in ALD patients. In the following clinical article Cheng et al. sought to characterize the sera metabolite fingerprints in ALD patients with and without ascites and found that ascites in ALD patients is closely associated with abnormalities in amino acid and lipid metabolism. The authors concluded that exploration of these metabolites be a novel biomarker or potential therapeutic targets in ALD patients. Neuman et al. in their article documented the persistence of characteristic features of ALD, namely centrilobular inflammation and programmed cell death, even after 1 week of alcohol detoxification despite improving various parameters such as liver stiffness and transaminase levels. They further reported that while apoptosis marker is generally higher in cirrhotic patients, its levels increased in response to withdrawal only in non-cirrhotic patients. These results suggested a role of liver micro-environment that, independent of amount of alcohol consumption, causes continued cell death by apoptosis. The authors concluded that further studies on heavy drinkers undergoing alcohol withdrawal may help to better understand molecular mechanism of liver damage and resolution in patients with ALD.A set of articles presented clinical findings and addressed ways to improve patient outcomes. A retrospective study presented by Zhang et al. summarized specific molecular mechanisms and intervention effectors for both these common liver diseases. The authors acknowledged that despite multiple common features such as lipid accumulation, oxidative stress, inflammation, insulin resistance, dietary habits, the mechanisms promoting disease progression is different which requires diversified treatment approaches. Along the same theme, Rasineni et al. using a rat model, showed that even though both alcohol-associated and non-alcohol-associated fatty liver diseases are nearly histologically indistinguishable, the physiological mechanisms that cause hepatic fat accumulation are different, as are their responses to starvation.There were two manuscripts that compared alcohol-associated and non-alcohol-associated fatty liver diseases. A review paper by Lu et al. used both in vitro and in vivo models to illustrate that the protective effect of Qinggan Huoxue Recipe against alcohol-induced liver injury was by affecting lysophosphatidylcholine acyltransferase 3 and preventing endoplasmic reticulum stress. In their study, Chu et al. demonstrated that the leading mechanisms in liver injury development such as oxidative stress and pyroptosis were reversed by a phenolic acid compound, sinapic acid. The authors further showed that this compound is protective by potentially binding to bromodomain-containing protein 4, which functions as a transcriptional coactivator to carry out various pathophysiological activities. Another study by Arumugam et al. claimed that the therapeutic role of betaine in preventing liver injury in an animal model of binge drinking is via maintaining methylation potential. In addition to these preclinical studies, Yen et al. explored the clinical benefits of 12 weeks of treatment with antroquinonol extracted from a medicinal fungus, Golden-Antrodia camphorata, on hepatic function after alcohol consumption. As revealed, this agent suppressed ALT, AST, and triglyceride levels in patients with liver disease compared with the placebo group and was found to be safe for healthy subjects and patients with ALD.Several other articles in this Topic were solely devoted to the treatment/prevention of ALD. Overall, this Research Topic covers important aspects on ALD and provides comprehensive updated information on mechanisms to better understand the disease pathogenesis and potential new biomarkers/therapeutic targets. The published articles are recommended for scientists and physicians involved in basic, translational and/or clinical studies on ALD. We strongly feel that the efforts of the guest editors and the journal in developing this Research Topic will be a small but significant step towards understanding, awareness, and hopefully reducing the disease burden of ALD, which is the most common liver disease worldwide and currently contributing to over 25% of cirrhosis related deaths.


Traditional Chinese Medicine (TCM) treatment strategies are guided by pattern differentiation, as documented in the eleventh edition of the International Classification of Diseases (ICD). However, no standards for pattern differentiation are proposed to ensure inter-rater agreement. Without standardisation, research on associations between TCM diagnostic patterns, clinical features, and geographical characteristics is also not feasible. This diagnostic cross-sectional study aimed to (i) establish the pattern differentiation rules of functional dyspepsia (FD) using latent tree analysis (LTA); (ii) compare the prevalence of diagnostic patterns in Hong Kong and Hunan; (iii) discover the co-existence of diagnostic patterns; and (iv) reveal the associations between diagnostic patterns and FD common comorbidities.A total of 250 and 150 participants with FD consecutively sampled in Hong Kong and Hunan, respectively, completed a questionnaire on TCM clinical features. LTA was performed to reveal TCM diagnostic patterns of FD and derive relevant pattern differentiation rules. Multivariate regression analyses were performed to quantify correlations between different diagnostic patterns and between diagnostic patterns and clinical and geographical variables.n = 400), Hong Kong (n = 250), and Hunan (n = 150) samples, respectively, using the eight pattern differentiation rules derived. 52.7% to 59.6% of the participants were diagnosed with two or more diagnostic patterns. Cold-heat complex (59.8%) and spleen-stomach dampness-heat (77.1%) were the most prevalent diagnostic patterns in Hong Kong and Hunan, respectively. Spleen-stomach deficiency cold was highly likely to co-exist with spleen-stomach qi deficiency (adjusted odds ratio (AOR): 53.23; 95% confidence interval (CI): 21.77 to 130.16). Participants with severe anxiety tended to have liver qi invading the stomach .At least one TCM diagnostic pattern was differentiated in 70.7%, 73.6%, and 64.0% of the participants in the overall (Future updates of the ICD, textbooks, and guidelines should emphasise the importance of clinical and geographical variations in TCM diagnosis. Location-specific pattern differentiation rules should be derived from local data using LTA. In future, patients’ pattern differentiation results, local prevalence of TCM diagnostic patterns, and corresponding TCM treatment choices should be accessible to practitioners on online clinical decision support systems to streamline service delivery.The online version contains supplementary material available at 10.1186/s13020-022-00656-x. H.pylori) test [Functional dyspepsia (FD) is a disorder of gut-brain interaction characterised by postprandial fullness, early satiety, epigastric burning, and/or epigastric pain . These sri) test . Patientri) test , while tri) test . An overri) test .Regardless of disease definitions, FD is estimated to be affecting 10–40% of the population in Western countries and 5–30% in Asia , have liThe symptoms of FD resemble those of stomach pain and stomach stuffiness and fullness in Traditional Chinese Medicine (TCM) . Herbal A team of senior TCM practitioners in Hong Kong specialising in gastroenterology would like to standardise TCM diagnosis of FD for the department in order to reduce inter-rater variability in the diagnostic-to-treatment decision-making process among practitioners. They might first search for TCM clinical textbooks or guidelines that summarise TCM experts’ opinions to inform the standardisation process. Nevertheless, the TCM diagnostic schemes mentioned in these clinical textbooks are usually described in a “one-size-fits-all” manner without considering clinical relevance . For ins., signs and symptoms) in a repeatable manner, which might then facilitate standardisation [Given the limited clinical relevance of TCM clinical textbooks and guidelines, the senior TCM practitioners decided to search for TCM diagnostic instruments supported by research evidence instead. Such instruments might guide the collection of patients’ TCM clinical feature data  establishing the score-based differentiation rules using LTA, (ii) discovering the co-existence of TCM diagnostic patterns and their distributions, (iii) revealing the associations between TCM diagnostic patterns of FD and common comorbidities, and (iv) comparing the prevalence of different TCM diagnostic patterns in Hong Kong and Hunan, as well as geographical variations in constituting clinical features on the same patterns. The definitions of key terms used in this study are listed in Additional file n = 250) and Hunan  were sampled consecutively. Newspaper advertisements were also used for subject recruitment in Hong Kong to improve generalisability beyond the designated hospital. In both locations, our recruitment promotions only focused on the local communities. Potential subjects in Hong Kong and Hunan must be domiciled in respective locations. In brief consultations or phone-screening sessions, potential subjects were screened for eligibility by trained TCM practitioners. Medical records were then accessed and reviewed for eligibility confirmation. The recruitment period was from December 2020 to May 2021. This study was approved by the Joint Chinese University of Hong Kong—New Territories East Cluster Clinical Research Ethics Committee (Reference number: CREC 2018.325).Following the recommendations from the Quality Assessment of Diagnostic Accuracy Studies 2 , FD patiH.pylori-negative results, or had tested positive for H.pylori and had completed the course for H.pylori eradication;Completed oesophagogastroduodenoscopy within ten years with Having symptoms that fulfilled the Ford et al. Reference Standard for FD , with no ≥ 18 years of age; ANDProvided written informed consent.Subjects who fulfilled all the following criteria were included:Had a diagnosis of organic oesophageal or gastric diseases in the past month, including oesophagitis, gastro-oesophageal reflux disease, peptic ulcer, and predominant heartburn or acid regurgitation;Presence of unremoved stomach polyps;Ever received major abdominal surgery ;Pregnant at the time of enrolment;Experiencing major physical illnesses ; ORRefused to provide written informed consent.Subjects who fulfilled any of the following criteria were excluded:At both sites, participants were invited to complete an online questionnaire of four sections. The first section collected data on basic demographic and clinical characteristics. The second section evaluated their FD subtype via the Ford et al. Reference Standard for FD . IBS staLantern software [We used three sets of TCMQ-FD clinical feature data corresponding to three study samples to derive score-based pattern differentiation rules for TCM diagnostic patterns of FD. The dataset derived from the overall sample refers to the data collected from all 400 participants. The dataset for the Hong Kong sample is defined as the data collected from the 250 participants in Hong Kong. The dataset for the Hunan sample refers to the data collected from the 150 participants in Hunan. On the software , 44, we software , a quant(i) Statistical pattern discovery: The data were dichotomised based on a cut-off score of four. In other words, if a patient rated four or above on a clinical feature, that patient was deemed to express that clinical feature in a significant manner. The dichotomised data were fed to Lantern. The output was a global latent tree model (LTM), a tree-structured probabilistic graphical model with latent variables at the internal nodes and the observed variables  located at the leaf nodes –27. The (ii) Statistical pattern interpretation: Three TCM practitioners  were invited to determine the TCM diagnostic pattern connotations of the latent variables via discussions. Along with their TCM domain knowledge , 14, the(iii) TCM diagnostic pattern identification: The three TCM practitioners were then asked to determine, for each potential TCM diagnostic pattern from the previous step, whether all its essential clinical features were present in the data. A TCM diagnostic pattern was kept only if all TCM practitioners answered positively.(iv) TCM diagnostic pattern quantification: For each remaining TCM diagnostic pattern, a local LTM  was built on Lantern using relevant clinical features and latent variables. A local LTM was used to probabilistically partition the overall sample into two clusters and gave a definition of the TCM diagnostic pattern over the overall sample dataset .(v) TCM pattern differentiation rule derivation: The local LTMs were used to classify the participants in the overall sample. Each participant was assigned a soft label that specified the probability of belonging to a particular TCM diagnostic pattern. The soft labels were subsequently adopted to derive pattern differentiation rules using the Naïve Bayes approach, as illustrated in Zhang et al. . Accordin = 400), the Hong Kong sample (n = 250), and the Hunan sample (n = 150) using corresponding pattern differentiation rules. We summarised and compared the number of TCM diagnostic pattern(s) differentiated in individual participants and the prevalence of different TCM diagnostic patterns of FD across the three samples.We differentiated the TCM diagnostic patterns from the overall sample  and 95% confidence intervals (CIs). Hosmer and Lemeshow tests were conducted to evaluate the goodness of fit of the models. A p value of larger than 0.10 denoted an adequate fit.Multivariate logistic regressions were conducted to quantify the associations between different TCM diagnostic patterns and FD subtypes, comorbid IBS, geographic locations, and PHQ9, GAD7, and NDI scores. Pearson and Deviance tests were performed to assess the models’ goodness of fit. A n = 42), unavailable test results (n = 40), failure in fulfilling the diagnostic Reference Standard (n = 26), or declined participation (n = 24). Then, we provided 313 eligible participants with access to the online questionnaire for this study. In the end, a total of 250 valid online questionnaires were received and analysed, following the voluntary withdrawal of sixty-three participants.Figure n = 41), declined participation (n = 15), or unavailability of test results (n = 13). We provided 150 eligible participants with access to the online questionnaire. Ultimately, we were able to receive and analyse all 150 online questionnaires.On the other hand, we screened a total of 219 subjects in Hunan. Among them, sixty-nine were excluded due to organic oesophageal or gastric disease diagnoses  [A global LTM was constructed for the TCM clinical features of FD using the overall sample dataset Fig. . The Y-veatures) . The numeatures) . In otheA total of eight LTMs were finalised from the LTA, corresponding to eight TCM diagnostic patterns of FD Fig. : (a) splA score-based pattern differentiation rule was established for each TCM diagnostic pattern using the overall sample dataset Table . The difTable n = 400), Hong Kong (n = 250), and Hunan (n = 150) samples, respectively  revealed in three pairs. Spleen-stomach deficiency cold tended to co-exist with spleen-stomach qi deficiency  and vice versa . Spleen deficiency and qi stagnation tended to co-exist with spleen-stomach deficiency cold  and vice versa . Spleen deficiency and qi stagnation tended to co-exist with cold-heat complex  and vice versa .Results of the logistic regressions assessing the relationships between TCM diagnostic patterns in the overall sample are presented in Table The prevalence of different pairs of co-existing patterns in the overall sample is illustrated in Table p values of the Pearson and Deviance tests are larger than 0.10, indicating good model fit. Participants located in Hong Kong were more likely to experience spleen deficiency and qi stagnation , spleen deficiency with dampness encumbrance , and cold-heat complex  than those located in Hunan. Compared to the participants with overlapping subtypes, those with the PDS subtype tended to have spleen-stomach qi deficiency .Multivariate logistic regression results on the associations between TCM diagnostic patterns with various health-related variables are reported in Table Participants with liver qi invading the stomach were likely to have a higher burden of anxiety symptoms . Regarding the disease-specific quality of life, participants with spleen deficiency and qi stagnation  and stomach heat  tended to have slightly higher NDI symptom severity. Participants with spleen-stomach deficiency cold  and spleen-stomach dampness-heat  tended to have a higher quality of life in the aspects of eating and drinking. Participants with spleen deficiency with dampness encumbrance  were likely to have better knowledge and control over dyspeptic symptoms.n = 400), 73.6% in the Hong Kong sample (n = 250), and 64.0% in the Hunan sample (n = 150), using respective score-based pattern differentiation rules derived from LTA. With the capability of diagnosing around 70.0% of the participants, we anticipate that these differentiation rules can improve TCM diagnostic reliability in a substantial proportion of FD patients in routine practice. Clinical appropriateness of the diagnostic approach will be judged in consultations, during which the diagnostic decision can be confirmed, adjusted, or rejected via additional information elicited by physical examinations as well as pulse and tongue assessments. To unleash the potential of this approach, patient-reported clinical feature data may be collected online before consultations, and relevant diagnostic results may be made available to TCM practitioners immediately via automated data transmission to electronic health records or if feasible, clinical decision support systems [In this diagnostic cross-sectional study, we differentiated the TCM diagnostic pattern(s) of 70.7% of the participants in the overall sample  in the differentiation rule of spleen-stomach qi deficiency.We also illustrated the association between psychiatric comorbidities and TCM diagnostic patterns. Participants with more severe anxiety symptoms tended to have liver qi invading the stomach. In other words, TCM practitioners may expect a higher possibility of diagnosing liver qi invading the stomach in FD patients with anxiety. In routine practice, TCM practitioners should offer additional psychiatric assessments for patients having this TCM diagnostic pattern and arrange timely referrals if necessary. The association between liver qi invading the stomach and anxiety symptoms seems consistent with TCM theory. Excessive anger, which is likely to be accompanied by anxiety, is thought to cause the stagnation of liver qi , 14. SubOur findings revealed the potential necessity for customising treatments with consideration of geographical locations, a TCM theory that highlights the value of factoring in geographical variations when tailoring prescriptions for individual patients , 14. We The TCM diagnostic pattern of cold-heat complex is commonly caused by a combination of spleen yang deficiency and external dryness and heat . Hong KoPeople in China have a relatively long average weekly working time of 46.1 h . EvidencFurthermore, in terms of numerical scores, the importance of each clinical feature of the same TCM diagnostic patterns varied across samples. For example, the clinical feature of signs and symptoms exacerbated by pressure was the most important in differentiating cold-heat complex for participants in the overall sample and the Hong Kong sample. Nevertheless, it was the second most important clinical feature in the same pattern differentiation rule for the Hunan sample. Similarly, burning sensation in the stomach was an essential clinical feature in differentiating stomach heat among participants in the overall sample and the Hunan sample. However, it was ranked second in the differentiation rule for the same pattern in Hong Kong.If electronic clinical decision support systems were introduced to TCM practice, local pre-test probabilities of TCM diagnostic patterns of FD could be incorporated into computer-aided TCM diagnostic systems. Together with up-to-date information on the best TCM treatments, such innovation may streamline clinical decision-making by generating patient-specific recommendations based on patients’ clinical information and comorbidities , improveThe variations described above may also influence the choice of appropriate TCM treatments, according to the pattern differentiation principle. Table This coincidence may explain why these Chinese herbal formulae with functions of liver qi soothing and spleen nourishment outperformed the others. In the network meta-analyses, the included randomised controlled trials evaluated the effectiveness of Chinese herbal formulae without considering pattern differentiation for participant recruitment. If a majority of the participants in these trials had liver qi invading the stomach, as suggested by our results, then the use of Xiao Yao Pill, Modified Zhi Zhu Decoction, and Xiao Pi Kuan Wei Decoction would be the most suitable options. If this assumption holds, pattern differentiation may be less important for conditions with a high prevalence of a specific TCM diagnostic pattern because the prescription of specific Chinese herbal formulae targeting that diagnostic pattern would have a high chance of fitting correspondingly. It may explain why some TCM practitioners find pattern differentiation less relevant .Although specific Chinese herbal formulae may be offered as a targeted treatment for FD due to a relatively high prevalence of liver qi invading the stomach, participants with only one TCM diagnostic pattern accounted for only 11.3–14.5% across the three samples. A significant proportion of the participants were diagnosed with more than one TCM diagnostic pattern: 56.2% in the overall sample, 59.6% in the Hong Kong sample, and 52.7% in the Hunan sample.Via logistic regression analyses, we found that participants in the overall sample with liver qi invading the stomach were likely to experience spleen deficiency and qi stagnation and vice versa. Such co-existence involved as many as 25.5% of the participants in the overall sample. Through targeting the aspect of liver qi invading the stomach, it is expected that Xiao Yao Pill, Modified Zhi Zhu Decoction, and Xiao Pi Kuan Wei Decoction may still partially alleviate symptoms among patients with co-existing spleen deficiency and qi stagnation as they address the same disease mechanism of spleen qi deficiency.We also revealed other thirteen pairs of co-existing TCM diagnostic patterns from the overall sample dataset. The most common co-existing pair of TCM diagnostic patterns was spleen-stomach qi deficiency and spleen-stomach deficiency cold. It accounted for 32.8% of the participants in the overall sample. The best performing Chinese herbal formulae derived from NMA , 12, namFor example, a patient was judged to have a co-existing spleen-stomach qi deficiency and spleen-stomach deficiency cold under the pattern differentiation rules and was diagnosed with pale tongue with thin and white tongue fur, plus fine or weak pulse . AccordiThe application of TCM diagnostic pattern, liver qi invading the stomach, in determining treatment appropriateness resembles the role of predictive biomarkers for personalising oncology treatment. In this case, a single trait  separates a specific population  with respect to the outcome of interest  in response to targeted therapy  , 55. To Participanteligibility: The validated Rome IV diagnostic criteria for FD [a for FD  should bInterventionsandcomparisons: A six-arm trial should be performed to compare the effectiveness of specific Chinese herbal formulae that target liverqiinvadingthestomach among the subgroups (Fig. ups Fig. . In eachOutcomemeasures: Multiple expert-recommended endpoints for FD trials should be selected to facilitate a comprehensive understanding of outcome changes. Global symptom alleviation assessed on a dichotomous scale enables a global assessment [sessment , while isessment , namely sessment .Similar validation trials may be conducted for other conditions to study the possibility of applying LTA-based TCM diagnostic patterns as predictive biomarkers for specific TCM treatments.Several limitations of this study should be acknowledged. First, since the TCMQ-FD concerns only the clinical features presented in the last two weeks, it may not capture the dynamic property of TCM diagnostic pattern . TherefoWe derived eight LTA-based TCM diagnostic patterns of FD using data collected from Hong Kong and Hunan and established relevant score-based pattern differentiation rules for routine practice. We revealed the associations between FD subtypes, as well as psychiatric comorbidities, and TCM diagnostic patterns of FD. Variations in the prevalence of TCM diagnostic patterns and constituting clinical features among FD patients residing in different geographical locations were also quantified. Future updates of the ICD-11, TCM textbooks, and clinical guidelines on FD should stress the importance of considering individual characteristics and geographical locations in routine practice. Suppose clinical decision support systems were introduced to TCM practice. In this case, the results of pattern differentiation of FD patients could be made available to TCM practitioners via automated data transmission to electronic health record systems, along with local pre-test probabilities of TCM diagnostic patterns of FD and recommendations for the corresponding TCM treatments. This innovation could enable the implementation of accurate diagnoses and appropriate treatments. That said, implementation assessments are recommended for evaluating the facilities' capacity and preparedness and TCM practitioners' adoption of digital health applications.Additional file 1: Appendix 1. Definitions of key terms used in this study. Appendix 2. Probabilistic co-occurring clinical features in the latent variables of the global latent tree model illustrated in Fig.


Increased glutamine metabolism is a hallmark of many cancer types. In recent years, our understanding of the distinct and diverse metabolic pathways through which glutamine can be utilized has grown more refined. Additionally, the different metabolic requirements of the diverse array of cell types within the tumor microenvironment complicate the strategy of targeting any particular glutamine pathway as cancer therapy. In this Mini-Review, we discuss recent advances in further clarifying the cellular fate of glutamine through different metabolic pathways. We further discuss potential promising strategies which exploit the different requirements of cells in the tumor microenvironment as it pertains to glutamine metabolism in an attempt to suppress cancer growth and enhance anti-tumor immune responses. In fact, some tumors display net glutamine catabolism while others display net glutamine synthesis , 8. Addi cancers , 10. Fur or nuclear magnetic resonance (NMR) analysis and can be broadly classified as targeted (searching for known metabolites) or non-targeted (a discovery-based approach). Targeted analyses rely on large high-quality internal compound standard databases for reference, while non-targeted analyses create large high-dimensional data sets that require multivariate analysis for appropriate interpretation . Despiteeactions . The autThe effect of the microenvironment on metabolic programming of specific cellular constituents therefore can in part be reflective of the metabolic interdependence, or co-metabolism, of specific resident cell types. The notion that non-cancerous cells in the tumor microenvironment contribute to cancer cell metabolism and growth has been particularly well studied in the case of glucose utilization and has led to the development of the concept termed the “reverse Warburg effect”, or RWE Figure 2in silico growth models, which remained limited by glucose and oxygen under various modeling conditions  with subsequent conversion to alpha ketoglutarate (α-KG) allows for entry of glutamine-derived carbons into the TCA cycle to replenish intermediates that have been extracted for other biosynthetic reactions , Cmax was over 20% higher in the tumor with more than double the AUC value for detectable DON tumor versus serum over the course of administration , which inhibits not only glutaminase but a range of enzymatic reactions utilizing glutamine as a substrate . Likely stration .via pyruvate carboxylase (PC) for replenishment of TCA cycle intermediates  under conditions of glutamine blockade. Further studies suggested an additional mechanism of tumor control arose from alteration in myeloid-derived suppressor cell (MDSC) phenotype under glutamine antimetabolite therapy, with these typically pro-tumorigenic cells converting to a more pro-inflammatory phenotype while losing expression of IDO, the enzyme responsible for synthesizing the immunosuppressive metabolite kynurenine  but rather endowed them with a highly-activated, long-lived phenotype. Cell type-specific differences in metabolic compensation appear to be critical to this finding, such as the ability of TILs but not tumor cells to preferentially utilize pyruvate nurenine . These pAnother role of glutamine is fueling, along with glucose, the hexosamine biosynthesis pathway, or HBP, which provides the necessary glycosaminoglycans for extracellular matrix (ECM) synthesis and intracellular glycosylation reactions . The ratVβ3 sialylation, which facilitates tumor metastatic activity. Studies utilizing direct HBP inhibition have also demonstrated reduction in pancreatic patient-derived tumor xenograft outgrowths with genetic ablation or pharmacologic inhibition of the HBP enzyme phosphoacetylglucosamine mutase 3 (PGM3)  expression in primary tumors of breast cancer patients and shortened metastasis-free survival. In mice, the authors demonstrated that PHGDH interacts with phosphofructokinase, and the loss of this interaction increases flux through hexosamine biosynthesis . This in3 (PGM3) . These sGlutamine-derived α-KG is a critical cofactor utilized by a family of histone demethylases to control gene expression of many cancer-promoting genes . These rAdditional studies have shed light on how glutamine metabolism can control the epigenetic landscape of other critical cell populations within a tumor. Glutamine metabolism differentially affected T lymphocyte subsets in work by Johnson et al., with chromatin accessibility and gene expression altered to differentially restrict Th17 but promote Th1 development under conditions of glutaminase deficiency or inhibition . Glutamide novo nucleotide synthesis via the production of methylation substrates from SGOC that are critical for thymidine synthesis. Successful targeting of glutamine metabolism for perturbation of redox homeostasis will therefore rely on a more complete understanding of the metabolic requirements of all cell types within a tumor. Indeed, preclinical studies have shown that glutaminase inhibition can impair GSH synthesis and lead to oxidative stress-induced death in multiple types of AML, synergizing with other drugs that disrupt redox state (Glutamine-derived glutamate is used in the synthesis of glutathione (GSH), a tripeptide of glutamate, cysteine, and glycine which serves as a major cytosolic antioxidant in eukaryotes . Tumor cox state . Furtherox state . Glutathvia anaplerotic reactions that replenish amino acids used in nucleotide synthesis  during cancer progression , 59. In Alterations in tumor metabolism have attracted scientific attention for over a century. While modern approaches have demonstrated how metabolites are utilized in exquisite detail, recent studies suggest that the heterogeneous nature of the tumor microenvironment, the interconnected nature of cellular metabolism, and the plasticity of intracellular metabolic pathways create significant hurdles to successful application of targeting a single, highly specific glutamine metabolic pathway such as glutaminase activity. Evidence of competition for glucose and differential glucose metabolism between cells within the tumor microenvironment has existed for some time . We now MDC wrote the manuscript and created the figures. RL revised the manuscript and provided scientific insight regarding literature selection.The study was funded by the following: The Bloomberg-Kimmel Institute for Cancer Immunotherapy, R01CA226765 (Robert Leone - Role: PI/PD) R01CA229451 (Robert Leone - Role: Key Personnel).MDC declares no conflicts of interest. RL is an inventor on JHU patents covering novel glutamine antagonist prodrugs. These patents have been licensed to Dracen Pharmaceuticals, Inc.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.


The definition of sudden sensorineural hearing loss (SSNHL) is broadly accepted as acute sensorineural hearing loss of more than 30 dB over at least three consecutive frequencies in a pure-tone audiogram (PTA). Acute audiovestibular loss is common with ischaemic stroke in the territory of the anterior inferior cerebellar artery (AICA). However, cases in which SSNHL and vertigo occur with hypoperfusion alone are very rare. We describe a patient who developed unilateral SSNHL and vertigo as initial symptoms caused by cerebellar hypoperfusion by vertebral artery (VA) dissection without the occurrence of infarction.A 51-year-old man suddenly developed acute hearing loss (AHL) in his left ear and vertigo. On neurological examination, he had vibration-induced right-beating nystagmus and left-beating nystagmus after a head-shaking test. Additionally, he had apogeotropic nystagmus during head turns to either side. The head impulse test (HIT) was normal. PTA showed mild unilateral SSNHL in the left ear. Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) showed territorial perfusion deficits in the left posterior inferior cerebellar artery (PICA) and anterior inferior cerebellar artery (AICA) without infarction. Two months later, the patient had no vertigo but still had hearing impairment in his left ear. A follow-up PTA documented persistent unilateral SSNHL in the left ear. Additionally, perfusion computed tomography (CT) showed that perfusion deficits remained in the left cerebellum along the PICA and AICA territories.Our case highlights a case of AHL and vertigo presented by isolated cerebellar hypoperfusion without infarction. It is necessary to consider the possibility of a central cause in patients with AHL and vertigo, and it is important to confirm this possibility through brain magnetic resonance imaging (MRI), including PWI, and magnetic resonance angiography (MRA). Sudden sensorineural hearing loss (SSNHL) is a sudden and unexplained hearing loss that is frequently unilateral. The US National Institute for Deafness and Communication Disorders defines SSNHL as an idiopathic hearing loss of at least 30 dB over at least 3 test frequencies within 72 hours . The aetThe evidence suggests that the development of SSNHL can be an initial warning sign of vascular events, such as thromboembolism, vasospasm, and insufficient blood circulation , 3. AudiThere have been reports of SSNHL related to infarction, especially AICA territorial infarction, and although infarction was subsequently observed, it occurred at a site different from the hypoperfusion area; furthermore, it is known that cases in which SSNHL and vertigo occur with hypoperfusion alone are very rare. We describe a patient who developed unilateral SSNHL and vertigo as initial symptoms caused by cerebellar hypoperfusion by vertebral artery (VA) dissection without the occurrence of infarction.A 51-year-old man presented with a sudden loss of hearing in his left ear. He also noted vertigo and imbalance. Approximately three times over the previous week, the patient had experienced transient hearing loss and vertigo lasting between 5 and 10 minutes. The patient had a history of hypertension and heavy smoking but he did not have a history of hearing impairment, head trauma, central nervous system infection, autoimmune diseases, or exposure to ototoxic drugs.On neurological examination, he had vibration-induced right-beating nystagmus and left-beating nystagmus after a head-shaking test. Additionally, he had left-beating nystagmus in the right roll test and right-beating nystagmus in the left roll test. The head impulse test was normal. Analysis of blood contents, including complete blood count, serum electrolytes, liver and kidney function indicators, and high-sensitivity C-reactive protein (hsCRP), were normal, except for an increased LDL-cholesterol level 130 mg/dL). Pure-tone audiogram (PTA) showed a mild unilateral sensorineural, pure-tone average of 37 dB (dB) in the left ear  of the brain was performed 9 hours after the last event. Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps showed normal findings Fig. B. PerfusWe started treating the patient with 75 mg of clopidogrel and 40 mg of atorvastatin. After starting treatment, his vertigo gradually improved, but his SSNHL did not change. Follow-up DWI and ADC mapping performed 3 days after onset showed multifocal infarctions along the posterior circulation involving the upper cerebellum and occipital lobe, not the PICA and AICA territories Fig. . Two monHearing impairment seriously affects not only the physical and mental health of patients but also the social life and activities of daily living. Circulation system disorders, such as ischemic stroke and myocardial infarction have closely related to SSNHL . BecauseIn this case, the patient had intermittent unilateral hearing loss and vertigo 1 week before the onset of symptoms. This shows that our patient was in the same situation described with infarction of one of the eight subgroups of the AICA area: sudden onset of audiovestibular syndrome with vertigo and hearing loss that is occasionally preceded by a prodromal episode(s) of audiovestibular disturbance , 9. Our In this case, overall hypoperfusion, including in the AICA and PICA territories observed with PWI, is thought to be the cause of the AHL and vertigo due to the prodromal symptoms of infarction. However, the pattern of cerebral infarction observed in follow-up DWI was not the previously known AICA, and the PICA infarction showed the possibility that isolated cerebellar hypoperfusion alone can induce persistent AHL. There are few studies on AHL and isolated cerebellar hypoperfusion. In one study involving acute transient vestibular syndrome (ATVS), The ipsilesional VA stenosis or occlusion may cause unilateral cerebellar hypoperfusion in patients with ATVS. Almost 80% of patients with cerebellar hypoperfusion revealed luminal abnormality or corresponding VA hypoplasia . In addiThere are some reports that an initial normal MRI does not rule out vascular aetiology . HoweverIn a study of patients with AHL due to posterior circulation ischaemia, nearly 80% of the patients who were followed for at least 1 year after the onset of sudden deafness due to vascular cause (mainly cerebellar infarction of the AICA territory) had a partial or complete recovery of hearing. Multivariate analysis revealed that multiple vascular risk factors for ischaemic stroke and profound hearing loss had poorer outcomes regarding recovery from AHL [Although the exact mechanism of the long-term outcome of AHL associated with VBIS is not clearly understood, the maximum improvement is usually seen within the first 2 weeks after the onset of hearing loss . The proThe HINTS examination  provides the earliest collection of physical examination findings developed to reliably rule out a central cause of hearing loss from a peripheral cause . Any othAlthough HINTS has been used academically for more than 10 years, There are still limitations to practical use in clinical practice. Many physicians in acute emergency settings tend to rely on neuroimaging because they lack the confidence to use their examination and interpretation of eye movements to make a critical decision about whether a patient has had a stroke. This means that the usefulness of HINTS strongly depends on the level of expertise of the person performing it . AdditioWe treated the patient with clopidogrel and atorvastatin. Treatment for dissection aims to prevent arterial rupture and further ischaemia and infarction while preserving blood supply to the associated vascular territory . CurrentIn conclusion, we reported a case of AHL and vertigo due to isolated cerebellar hypoperfusion without infarction. If a brain MRI, including PWI, was not performed in this case, the diagnosis and treatment of cerebellar ischaemia may have been delayed. Therefore, it is necessary to consider the possibility of a central cause in patients with AHL and vertigo, and it is important to confirm it through brain MRI, including PWI, and magnetic resonance angiography (MRA).


Salmonella typing scheme for reporting the disease prevalence of the enteric pathogen. With the advent of whole-genome sequencing (WGS), in silico methods have increasingly replaced traditional serotyping due to reproducibility, speed and coverage. However, despite integrating genomic-based typing by in silico serotyping tools such as SISTR, in silico serotyping in certain contexts remains ambiguous and insufficiently informative. Specifically, in silico serotyping does not attempt to resolve polyphyly. Furthermore, in spite of the widespread acknowledgement of polyphyly from genomic studies, the prevalence of polyphyletic serovars is not well characterized. Here, we applied a genomics approach to acquire the necessary resolution to classify genetically discordant serovars and propose an alternative typing scheme that consistently reflect natural Salmonella populations. By accessing the unprecedented volume of bacterial genomic data publicly available in GenomeTrakr and PubMLST databases (>180 000 genomes representing 723 serovars), we characterized the global Salmonella population structure and systematically identified putative non-monophyletic serovars. The proportion of putative non-monophyletic serovars was estimated higher than previous reports, reinforcing the inability of antigenic determinants to depict the complexity of Salmonella evolutionary history. We explored the extent of genetic diversity masked by serotyping labels and found significant intra-serovar molecular differences across many clinically important serovars. To avoid false discovery due to incorrect in silico serotyping calls, we cross-referenced reported serovar labels and concluded a low error rate in in silico serotyping. The combined application of clustering statistics and genome-wide association methods demonstrated effective characterization of stable bacterial populations and explained functional differences. The collective methods adopted in our study have practical values in establishing genomic-based typing nomenclatures for an entire microbial species or closely related subpopulations. Ultimately, we foresee an improved typing scheme to be a hybrid that integrates both genomic and antigenic information such that the resolution from WGS is leveraged to improve the precision of subpopulation classification while preserving the common names defined by the WKL scheme.The White–Kauffmann–Le Minor (WKL) scheme is the most widely used  The GenomeTrakr genomes were retrieved from the National Center for Biological Information (NCBI) GenBank database. The PubMLST genomes were retrieved using the BIGSdb API.The assembly accession numbers of the genomes analysed in this study  is a major foodborne pathogen responsible for an annual incidence rate of more than 90 million cases of foodborne illnesses worldwide. Today, global Salmonella surveillance relies heavily on serotyping for disease tracking, risk assessments and data sharing across jurisdictions. However, despite previous Salmonella genomic studies reporting discordance between phylogenomic clades and serovars, the prevalence of polyphyletic serovars remains poorly understood. The collective genomic characterization of Salmonella thus far, has also yet led to a standardized genomic-based typing method for Salmonella longitudinal surveillance that resolves polyphyly. To better understand and address the limitations of Salmonella serotyping, we analysed over 180 000 S. enterica genomes representing 723 predicted serovars to subdivide the population into evolutionarily stable clusters and propose a stable organization of the Salmonella population structure. Analysing nAWC across cgMLST distance thresholds was demonstrated to be an effective means to subdivide large-scale bacterial genomic datasets into stable and functionally divergent clusters that can assist the development of standardized genomic-based typing nomenclatures. The compiled list of non-monophyletic serovars highlighted the previously underestimated prevalence of serotyping inconsistencies and the complexity of Salmonella genealogy. By exploring the possibility of erroneous in silico serotyping calls, we demonstrated minor discrepancies between reported and predicted serotyping results that could be associated to in silico misprediction, laboratory testing error or human errors. More importantly, we observed the urgent need for controlled vocabulary integration in open data settings to strengthen typing data utility and reinforce analysis reproducibility.Salmonella enterica (S. enterica) is a significant public health burden that causes more than 90 million cases of foodborne infections globally every year ,12:i:-, Javiana, Infantis, Muenchen, Montevideo, Thompson, Saintpaul, Oranienburg, Mississippi, Bareilly, Paratyphi B var. Java, and Anatum.According to T. However, significant bias was indeed observed in the relative abundance across the Enteritidis clusters. The global Enteritidis strains appeared to have expanded from an epidemic clone, as 33 980 (99.4 %) Enteritidis isolates in the dataset were classified under a single cluster, Cluster 841. It is unlikely that the minor clusters were mispredicted due to data quality, as their average genome completeness and contamination were within 1 % difference from that of Cluster 841. Hence, these minor clusters likely represent real Enteritidis subpopulations.In contrast to previous reports, which described the serovar Enteritidis to be sequence-type-specific and highly clonal , we founT . Of the clinically significant serovars, Bareilly, Javiana, Mississippi, Montevideo, Muenchen, Newport, Oranienburg, Paratyphi B var. Java, Saintpaul and Thompson more closely approximated uniform cluster distribution (Shannon entropy ≈ 1), indicating that the lineages of these serovars are equally prevalent unlike Enteritidis.To distinguish between uniform and skewed cluster distribution across these multi-lineage serovars, we compared the Shannon entropy of each clinically significant serovar at the most stable T, we systematically identified serovars of a common lineage by searching for instances of multi-serovars clustering. Overall, 452 of the 1342 (33.7 %) genomic clusters were found to consist of two or more different in silico serovars, suggesting that each grouping of these ‘sister-serovars’ share stable genomic contents. Examples included the shared lineage between Lubbock and Mbandaka, the inter-serogroup clustering of the serovars Bredeney (B), Give (E1), Kimuenza (B) and Schwarzengrund (B), as well as the within-serogroup B clustering of the serovars Brandenburg, Reading, Madras and Sandiego. We have provided the cluster assignments defined at the median T of the 43 different cluster stable regions in Table S1 to enable queries of genetically related serovars.Given the clustering data at the most stable in silico serotyping tools leverage the correlation between genome-wide variations and serovars for in silico prediction, this observed correlation has yet been systematically evaluated across most serovars on a large scale. We began by characterizing a list of genomically similar serovars to assess whether genomically similar serovars also share similar antigenic combinations. We defined pairs of genomically similar serovars based on the clustering observed at the earliest signature of stability (T=45). In this region, a total of 23 748 clusters were predicted, of which 23 584 (99.31 %) clusters contained isolates of a single in silico serovar. Subsequent investigation of the other 164 (0.69 %) clusters led to the identification of a total of 65 genomically similar serovar pairs . Low confidence in silico serovar predictions were excluded when determining compositionally mixed clusters to avoid inferring artificial relationships due to erroneous in silico serotyping. As expected, phenotypic phase variants of Typhimurium and Paratyphi B/Paratyphi B variant Java were amongst the identified serovar pairs that shared highly similar core genomes . We observed a total of 19 genomically similar serovar pairs with different O-antigens (i.e. different serogroups) and four serovar pairs that differed by two or more antigenic types . The serovar pairs that shared dissimilar antigens primarily comprised of rarely sampled serovars such as Madras, Winterthur and Moscow. Due to the sparse sampling of these serovars, there was insufficient evidence to suggest a dissociation between antigenic and genomic variation.Although existing sistr serovar predictions and the reported serovars in the metadata (Table S4). Notably, sistr could not distinguish between the O-6 antigen serovar pairs reported by Mikoleit et al. ,12:i:-”, ‘typhimurium monophasic’, ‘typhimurium - monophasic’, “4,[5],12:i:-”, “1,4,[5],12:i:-”, “I 4,5,12:i:-”, “4,5,12:i”, and “4,5,12:i-”. However, the remaining 29.6 % of the discrepancies in high-quality genomes are likely unrelated to data quality or semantics, and instead related to potential errors in in silico serovar prediction or reports in public databases. Examples include the aforementioned O-6 antigen serovar pairs and 1086 other unique mismatches listed in Table S6. Following the correction for discrepancies due to data quality and semantics, the overall concordance rate between serotyping reports and predictions increased to 96.9 %, suggesting that misclassification by in silico serotyping has a relatively minor effect on our analyses.Our estimation of inter- and intra-serovar similarity could be significantly confounded by erroneous Salmonella dataset of 180 098 genomes, we demonstrated that the global population structure of the enteric pathogen can be arranged into 1342 stable subpopulations. The robustness of our cluster definition is derived from the fact that the cluster assignments, richness and evenness remain stable across a wide range of distance cutoffs. Moreover, the validity of our population structure analysis can be demonstrated from the evident correlation between serotyping and genomic variation observed from the phylogenetic tree  that documents the putative non-monophyletic serovars, as well as the serovars that belong to the same lineage as the putative non-monophyletic serovars.Our discovery of over 200 serovars that had not been reported as putative non-monophyletic classifications is a further indication of the negligence of genomic investigations for many serovars thus far. Moreover, previous studies often selected a minor subset of genomes to represent a given serovar leading to insufficient coverage of genetic diversity and consequently the assumption of monophyly . Hence, Salmonella into 1342 groups based on the most stable T, a genomic-based typing scheme can be developed. A single sequence can be selected from each stable cluster to construct a set of reference sequences that collectively represent the global Salmonella population structure. Subsequent alignments of query sequences to the reference sequences would thus inform the subtypes of the query genomes based on the most similar reference.The deficiencies of serotyping for longitudinal surveillance can be addressed by WGS, given its capability to survey genome-wide markers and thereby empower genomics researchers to model the divergence of bacterial populations with greater precision and resolution. By subdividing T’s to define stable Salmonella clusters represented by hierarchical cluster codes [Salmonella subpopulations such as subspecies, superlineages and eBGs [Salmonella. An alternative solution is major antigenic cluter typing introduced by Chattaway et al. [In fact, a similar solution has already been implemented in Enterobase that integrates the application of cgMLST er codes . The Entand eBGs . Integray et al.  that mery et al. . One prihttps://chewbbaca.online/) could be a highly promising avenue to synchronize local schema with globally maintained schema and centralize a collection of gene-by-gene subtyping schema for microbial pathogens [With a multitude of genomic solutions available, the next steps towards global standardization should include community convergence on a universal genomic-based typing scheme and collaborative efforts to characterize the functional differences, ecological adaptations and health risks associated with each subpopulation in order to maximize the utility of genomic-based typing. Moreover, community consensus on a core- or whole-genome MLST scheme is critical to converge on a fixed set of genome-wide loci for comparison and reinforce a standardized allele number nomenclature. In particular, the Chewie Nomenclature Server (athogens .sistr predictions and reported serovars solely due to semantics. The unrestrictive entry of serovar information in GenomeTrakr and PubMLST hindered the accurate estimation of the number of serovars in the study dataset based on the reported serovars in the metadata alone. Moreover, it rendered the estimated 90.6 % concordance rate between sistr predictions and reported serovars to likely represent an underestimation of the true concordance rate. Our uncorrected concordance rate was in fact, marginally lower than a previous estimate of 91.91 % [Salmonella sequences by eliminating the need for time-consuming data harmonization and thus reinforcing analysis reproducibility.The importance of standardization and data harmonization cannot be undermined, as the lack of controlled vocabularies in open data settings hinders data interpretability and summarization. The high degree of metadata inconsistencies in public foodborne pathogen databases is evident from the frequent discrepancies between  91.91 % . The intSalmonella Enteritidis had estimated the most recent common ancestor of present-day Enteritidis lineages to have existed around the 1600s when cross-continental overseas trades were increasingly embraced [in vitro metabolic activities of the two Enteritidis populations and correlating differential metabolic activities to the divergence of lineage-specific alleles to test our hypotheses.To explore the application of nAWC to reveal cluster consolidation dynamics and inform evolutionary histories, we analysed the genomic differences between two geographically segregated Enteritidis lineages that converged at a cluster destabilizing threshold. The pronounced allele frequency bias across different geographical regions demonstrated from genome-wide association analyses suggested that the observed lineage divergence could be a consequence of niche adaptation or founder effects. A previous study on the evolutionary history of embraced . Hence, embraced . We recoSalmonella population structure and discovering novel genetic patterns that differentiate microbial subpopulations. Our study is a further demonstration of how global genomic data sharing benefits scientific research. The increasing open accessibility of large-scale genomic datasets with minimal metadata fields will foster new directions to investigate molecular evolution and microbial diversity. With the growing integration of genomics in infectious disease surveillance worldwide, we encourage joint efforts across scientific research and public health to standardize a genomic-based typing nomenclature for global disease reporting such that Salmonella typing consistently reflect both genetic relatedness and epidemiological significance.In the genomics era, the development of efficient bioinformatic tools and high-throughput sequencing has revolutionized our understanding of microbial evolution and biology. Here, we continued to echo the value of genomic data by proposing systematic ways to define the global Click here for additional data file.Click here for additional data file.


Atrial fibrillation (AF) is the most persistent arrhythmia today, with its prevalence increasing exponentially with the rising age of the population. Particularly at elevated heart rates, a functional abnormality known as cardiac alternans can occur prior to the onset of lethal arrhythmias. Cardiac alternans are a beat-to-beat oscillation of electrical activity and the force of cardiac muscle contraction. Extensive evidence has demonstrated that microvolt T-wave alternans can predict ventricular fibrillation vulnerability and the risk of sudden cardiac death. The majority of our knowledge of the mechanisms of alternans stems from studies of ventricular electrophysiology, although recent studies offer promising evidence of the potential of atrial alternans in predicting the risk of AF. Exciting preclinical and clinical studies have demonstrated a link between atrial alternans and the onset of atrial tachyarrhythmias. Here, we provide a comprehensive review of the clinical utility of atrial alternans in identifying the risk and guiding treatment of AF. Atrial fibrillation (AF) is the most common cardiac arrhythmia observed today, affecting roughly 33 million people globally . DespiteAF was first shown to be instigated by ectopic triggers located in the atrial sleeve of the pulmonary veins by Haïssaguerre et al. . Radio-fTo improve the likelihood of success, multiple theories for identifying triggers and ectopic activity initiating outside the pulmonary veins and instigating AF have been investigated. It is now widely accepted that the development and maintenance of AF require both arrhythmogenic triggers and a suitable substrate . Variati2+) and contraction, have been suggested to play a significant role in the generation of proarrhythmic substrates and facilitate re-entry phenomena that can ultimately lead to sustained AF i dynamics affect Vm regulation via Ca2+-dependent ion currents and transporters that define the bi-directional coupling of Vm and [Ca2+]i. Yet, there remains an ambiguity over the fundamental mechanism for the origin of alternans, perturbations of Vm, or [Ca2+]i regulation, as studies have validated both assumptions. Therefore, the mechanisms of alternans remain incompletely understood, especially in atrial tissue.Cardiac alternans, first described by Heinrich Hering in 1908 as a cyclic beat-to-beat alternation in contraction force, intracellular Caial (Vm) . Vm dire+) ion channels and their subunits, such as the ultra-rapid delayed rectifier current (IKur) and the transient outward K+ current, initiate faster atrial repolarization, leading to shorter APDs compared with ventricular myocytes [2+ and K+ dynamics. AF may lead to reduced mRNA expression for subunits of L-type Ca2+ channels, resulting in intracellular Ca2+ overload [+ current. These interactions between the ion channel modifications due to aging or ischemia promote shortening of the atrial APD during AF and facilitate atrial APD maladaptation [In the case of atrial tissue, irreversible damage to the atrial substrate over time due to aging causes severe atrial remodeling that can lead to alterations in P-wave duration and morphology . Old agemyocytes . Howeveroverload , as wellaptation ,14.Other factors like intensifying calcium oscillations due to atrial stretch and dilation, remodeling of connexins, and gap junctions also play a role in APD changes ,18. Thes2+ release slope, which initiated Ca2+-driven alternans. These results highlighted that disturbed Ca2+ homeostasis drives proarrhythmic APD alternans in AF patients and may be significantly influenced by RyR kinetics [2+ transients and APD alternans by altering calcium dynamics and increasing their variability. Their results indicated that AF remodeling enhanced spontaneous single-cell Ca2+ release, prolonged the refractory period of the Ca2+ transient, increased the slope of the Ca2+ transient restitution curve, and eventually predisposed hearts to Ca2+ transient alternans [2+ transient amplitude and SR Ca2+ concentration. They demonstrated that the enhanced SR Ca2+ reuptake was the primary reason that HF-induced atrial electrical remodeling increased susceptibility to atrial alternans [To ascertain how cellular alterations in patients with AF impacted the manifestations of alternans at heart rates close to rest, electrophysiological remodeling associated with chronic AF was investigated using a computational model of human atrial tissue by Chang et al. . Their rkinetics , a phenokinetics ,22. Similternans . Furtherlternans  revealedlternans .The role of atrial alternans in AF pathophysiology has been investigated extensively using preclinical animal models over the past couple of decades . Atrial 2+ handling were responsible for a lower alternans threshold in older animals. It was demonstrated that key changes in calcium dynamics including decreased peak L-type Ca2+ current, increased SR Ca2+ content, decreased Ca2+ transient amplitude, and slowed reuptake of Ca2+ into the SR driven by increased Ca2+ buffering predisposed the aged myocytes to developing atrial alternans [A major risk factor for AF is age and studies conducted in sheep models have shown that aging is associated with a reduction in the threshold for action potential alternans, both in-vivo and in isolated myocytes . The maglternans . Their rlternans .+ levels and the risk of AF [+ agonists might be an applicable approach to prevent the development of Ca2+ transient alternans in rabbits [Another interesting study tested the correlation between serum Ksk of AF . In a 12sk of AF . Support rabbits . SpecifiVarious features of the P-wave duration and morphology, corresponding to atrial depolarization, have been studied to predict the incidence of AF ,31,32 T. ElectriIn a clinical study on patients with chronic and paroxysmal AF, inter-regional differences in the slopes of the restitution curves were observed to be greater in patients with chronic AF than in those with paroxysmal AF or healthy controls . It was Another recent case study reported the presence of pulsus alternans, an alternation in the pulse strength that has been linked to severe HF, instigated by atrial flutter, which ceased on cardioversion . A more 2+ channel blockers, digitalis, and amiodarone. For rhythm control, the main goal is to sustain sinus rhythm and attenuate uncomfortable symptoms to improve the everyday quality of life [The current pharmacological treatments for AF are mainly divided into three categories: rate control, rhythm control, and stroke prevention. The target audience for rate control therapy are patients aged >65 years, as these medications help reduce recurring hospitalizations by aiming to maintain a resting heart rate of <80 bpm . Commonl of life .Direct current cardioversion is an effective therapy for AF patients or AF with rapid ventricular response to restore sinus rhythm, and it is mainly recommended for AF patients who do not respond to pharmacological therapies, combined with HF or hemodynamic instability . In addiPulsed field ablation (PFA) is a promising treatment strategy wherein fast and short-duration non-thermal energy is delivered to cardiomyocytes using electroporation, which damages their structural integrity, leading to isolated death of the target cell. In comparison with other thermal ablation procedures, PFA can be delivered ultra-rapidly in sub-seconds by both percutaneously delivered endocardial and surgically placed epicardial catheters . Thanks Another surgical option is Cox maze IV procedure, which is currently the gold-standard surgical treatment for AF, with a 93% non-recurrence of AF at one year and a 78% freedom from AF at five years . FinallyIn interventional procedures, a novel study investigated the termination of spiral wave arrhythmias using light waves, given its minimal side effects and non-invasiveness . Using oThe search for substrate-driven AF assessment and treatment has been gaining increased research attention over the past decade. Variations in P-wave morphology and duration have been directly linked to the substrate dependent conduction abnormalities observed in AF patients . A novelRecent clinical studies have also demonstrated the potential of cardiac alternans as a biomarker of vagal stimulation treatment efficacy in patients with both atrial and ventricular tachyarrhythmias ,49. CardDespite the promising preliminary results highlighting the utility of cardiac alternans in assessing the risk of AF, further studies are warranted to test its efficacy in substrate mapping for guiding ablation therapy. Extensive evidence demonstrating the predictive capabilities of both T-wave repolarization and P-wave atrial alternans has been reported over the past two decades. Yet, its clinical applicability in guiding treatment strategies is limited, primarily because of the patient-to-patient variability and a non-standardized approach for calculating alternans levels, and hence the impending risk of tachyarrhythmias. Recent data suggest a more patient-specific approach would likely be more effective in guiding treatment strategies. Screening for atrial alternans may provide an indication of the risk of AF and help improve patient management strategies.