Porphyromonas gingivalis Impairs Oral Epithelial Barrier through Targeting GRHL2.

Oral mucosa provides the first line of defense against a diverse array of environmental and microbial irritants by forming the barrier of epithelial cells interconnected by multiprotein tight junctions (TJ), adherens junctions, desmosomes, and gap junction complexes. Grainyhead-like 2 (GRHL2), an epithelial-specific transcription factor, may play a role in the formation of the mucosal epithelial barrier, as it regulates the expression of the junction proteins. The current study investigated the role of GRHL2 in the Porphyromonas gingivalis (Pg)-induced impairment of epithelial barrier functions. Exposure of human oral keratinocytes (HOK-16B and OKF6 cells) to Pg or Pg-derived lipopolysaccharides (Pg LPSs) led to rapid loss of endogenous GRHL2 and the junction proteins (e.g., zonula occludens, E-cadherin, claudins, and occludin). GRHL2 directly regulated the expression levels of the junction proteins and the epithelial permeability for small molecules (e.g., dextrans and Pg bacteria). To explore the functional role of GRHL2 in oral mucosal barrier, we used a Grhl2 conditional knockout (KO) mouse model, which allows for epithelial tissue-specific Grhl2 KO in an inducible manner. Grhl2 KO impaired the expression of the junction proteins at the junctional epithelium and increased the alveolar bone loss in the ligature-induced periodontitis model. Fluorescence in situ hybridization revealed increased epithelial penetration of oral bacteria in Grhl2 KO mice compared with the wild-type mice. Also, blood loadings of oral bacteria (e.g., Bacteroides, Bacillus, Firmicutes, ß-proteobacteria, and Spirochetes) were significantly elevated in Grhl2 KO mice compared to the wild-type littermates. These data indicate that Pg bacteria may enhance paracellular penetration through oral mucosa in part by targeting the expression of GRHL2 in the oral epithelial cells, which then impairs the epithelial barrier by inhibition of junction protein expression, resulting in increased alveolar tissue destruction and systemic bacteremia.

[Development, Application and Evaluation of a Concept for Safe Patient Identification in Hospital - How can Knowledge Transfer Succeed?] / Entwicklung, Anwendung und Evaluation eines Konzeptes zur sicheren Patientenidentifikation im Krankenhaus ­ Wie kann der Wissenstransfer gelingen?

Aim of the Study: In order to minimise the risk of patient misidentification in clinical settings, the German Coalition for Patient Safety published recommendations for safety patient identification in 2008. The aim of this study was to develop, implement and evaluate a theoretical framework of knowledge transfer. The purpose of the framework was to enhance hospital staff's ability to apply the recommendations for safe patient identification in the daily routine of patient care. Method: A data bank-based research and literature review have been conducted. Research topics were: knowledge transfer, change management and implementation science. Within the application of the concept group interviews were held with hospital staff and the interview material was evaluated using content analysis. On this basis a tailored multifaceted implementation strategy has been developed and applied in 8 hospital wards of 4 hospitals belonging to a communal hospital concern. The evaluation of the developed knowledge transfer concept was conducted 4 weeks after the concept application with a written questionnaire. Results: The developed framework concept of knowledge translation consisted of 4 phases built on top of each other: initiation phase; analysis phase; implementation phase; evaluation phase. The multifaceted implementation strategy included 3 interventions: a poster, a computer-based training and a guideline for team meetings. The survey yielded responses from 56 individuals: 96% declared that they know about the existence of the recommendations for safe patient identification; 86% said that they know about the content of the recommendations; 91% have striven to apply the recommendations in the daily routine of patient care; 71% stated that the recommendations for safe patient identification have become integral part in the daily routine of patient care. To become aware of the recommendations and its content the respondents have used on average 2.3 interventions, however the effect of the CBS was relatively small. Conclusion: The developed theoretical framework concept for knowledge transfer provides a way to integrate the recommendations for safe patient identification in the daily routine of patient care and to counteract risk factors promoting misidentification. Therefore a multifaceted implementation strategy is promising.

[Can Quality of Patient Identification be Influenced by Training? - Results of a Randomised Multicentre Study with Multimodal Intervention]. / Welchen Einfluss haben Schulungen auf die Qualität der Patientenidentifikation? ­ Ergebnisse aus einer randomisierten, multizentrischen und multimodalen Interventionsstudie.

Background: Attributing clinical care to patients unambiguously is a precondition for patient safety. The German Coalition for Patient Safety has published a recommendation on this topic. Issue: The here presented study examined whether and to what extent documentation quality as one determining factor of correct patient identification can be improved positively by inter-professional training. Method: In our randomised multi-centric study physicians and nurses from 8 units in 4 hospitals were trained. The control group consisted of untrained unit teams. Effects of the intervention were measured by investigating documentation errors in clinical records before and after the training. Results: As a result of our intervention the number of documents with documentation errors/patient charts could be reduced by 37.3% (p<0.001). Conclusion: The results of the study point to the training of recommendations on preventing errors as an effective instrument for the improvement of patient safety.

Effect of anisotropy on ventricular vulnerability to unidirectional block and reentry by single premature stimulation during normal sinus rhythm in rat heart.

Single high-intensity premature stimuli when applied to the ventricles during ventricular drive of an ectopic site, as in Winfree's "pinwheel experiment," usually induce reentry arrhythmias in the normal heart, while single low-intensity stimuli barely do. Yet ventricular arrhythmia vulnerability during normal sinus rhythm remains largely unexplored. With a view to define the role of anisotropy on ventricular vulnerability to unidirectional conduction block and reentry, we revisited the pinwheel experiment with reduced constraints in the in situ rat heart. New features included single premature stimulation during normal sinus rhythm, stimulation and unipolar potential mapping from the same high-resolution epicardial electrode array, and progressive increase in stimulation strength and prematurity from diastolic threshold until arrhythmia induction. Measurements were performed with 1-ms cathodal stimuli at multiple test sites (n = 26) in seven rats. Stimulus-induced virtual electrode polarization during sinus beat recovery phase influenced premature ventricular responses. Specifically, gradual increase in stimulus strength and prematurity progressively induced make, break, and graded-response stimulation mechanisms. Hence unidirectional conduction block occurred as follows: 1) along fiber direction, on right and left ventricular free walls (n = 23), initiating figure-eight reentry (n = 17) and tachycardia (n = 12), and 2) across fiber direction, on lower interventricular septum (n = 3), initiating spiral wave reentry (n = 2) and tachycardia (n = 1). Critical time window (55.1 ± 4.7 ms, 68.2 ± 6.0 ms) and stimulus strength lower limit (4.9 ± 0.6 mA) defined vulnerability to reentry. A novel finding of this study was that ventricular tachycardia evolves and is maintained by episodes of scroll-like wave and focal activation couplets. We also found that single low-intensity premature stimuli can induce repetitive ventricular response (n = 13) characterized by focal activations.NEW & NOTEWORTHY We performed ventricular cathodal point stimulation during sinus rhythm by progressively increasing stimulus strength and prematurity. Virtual electrode polarization and recovery gradient progressively induced make, break, and graded-response stimulation mechanisms. Unidirectional conduction block occurred along or across fiber direction, initiating figure-eight or spiral wave reentry, respectively, and tachycardia sustained by scroll wave and focal activations.

Cellular Components Mediating Coadherence of Candida albicans and Fusobacterium nucleatum.

Candida albicans is an opportunistic fungal pathogen found as part of the normal oral flora. It can be coisolated with Fusobacterium nucleatum, an opportunistic bacterial pathogen, from oral disease sites, such as those involved in refractory periodontitis and pulp necrosis. The physical coadherence between these 2 clinically important microbes has been well documented and suggested to play a role in facilitating their oral colonization and colocalization and contributing to polymicrobial pathogenesis. Previous studies indicated that the physical interaction between C. albicans and F. nucleatum was mediated by the carbohydrate components on the surface of C. albicans and the protein components on the Fusobaterium cell surface. However, the identities of the components involved still remain elusive. This study was aimed at identifying the genetic determinants involved in coaggregation between the 2 species. By screening a C. albicans SN152 mutant library and a panel of F. nucleatum 23726 outer membrane protein mutants, we identified FLO9, which encodes a putative adhesin-like cell wall mannoprotein of C. albicans and radD, an arginine-inhibitable adhesin-encoding gene in F. nucleatum that is involved in interspecies coadherence. Consistent with these findings, we demonstrated that the strong coaggregation between wild-type F. nucleatum 23726 and C. albicans SN152 in an in vitro assay could be greatly inhibited by arginine and mannose. Our study also suggested a complex multifaceted mechanism underlying physical interaction between C. albicans and F. nucleatum and for the first time revealed the identity of major genetic components involved in mediating the coaggregation. These observations provide useful knowledge for developing new targeted treatments for disrupting interactions between these 2 clinically relevant pathogens.

[Improvement of medication safety by identification of genetically predisposed subjects. Personalized clinical strategies and regulatory advices]. / Erhöhung der Arzneimitteltherapiesicherheit durch Identifizierung genetisch prädisponierter Personen. Personalisierte klinische Ansätze und regulatorische Maßnahmen.

BACKGROUND: Because adverse drug events (ADEs) have a high socio-economic impact there is an urgent need for effective prevention. In addition to process-related avoidable errors personalised approaches for the prevention of ADEs should also focus on genetic polymorphisms as potential causative agents. AIM: Using five case reports as examples therapeutic modalities are described to illustrate the clinical impact of prospective testing aimed at estimating the individual risk of susceptible subjects. MATERIAL AND METHODS: The role of the HLA system, the cytochrome P450 family, other metabolic enzymes and transport proteins are described to illustrate the broad range of genetic susceptibility. It is shown, why, when and for whom pretherapeutic tests on genetic polymorphisms are recommended to reduce the risk of ADEs. RESULTS: The determination of genetic susceptibility is already implemented in clinical practice prior to (1) carbamazepine therapy in south-east Asians and (2) treatment with abacavir independent of ethnicity. Before prescribing carbamazepine or abacavir, it is recommended that therapeutic decisions be based on these test results. CONCLUSION: The broad application of personalised medicine used as an effective tool for minimizing ADE risks is limited by the evidence-based benefit for the patient on the one hand and the costs of the test on the other hand.

The effect of massage on heart rate variability in preterm infants.

OBJECTIVE: To test the hypothesis that massage would improve autonomic nervous system (ANS) function as measured by heart rate variability (HRV) in preterm infants. STUDY DESIGN: Medically stable, 29- to 32-week preterm infants (17 massage, 20 control) were enrolled in a masked, randomized longitudinal study. Licensed massage therapists provided the massage or control condition twice a day for 4 weeks. Weekly HRV, a measure of ANS development and function, was analyzed using SPSS generalized estimating equations. RESULTS: Infant characteristics were similar between groups. HRV improved in massaged infants but not in the control infants (P<0.05). Massaged males had a greater improvement in HRV than females (P<0.05). HRV in massaged infants was on a trajectory comparable to term-born infants by study completion. CONCLUSION: Massage-improved HRV in a homogeneous sample of hospitalized, medically stable, preterm male infants and may improve infant response to exogenous stressors. We speculate that massage improves ANS function in these infants.

Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans.

Streptococcus mutans is generally considered to be the principal etiological agent for dental caries. Many of the proteins necessary for its colonization of the oral cavity and pathogenesis are exported to the cell surface or the extracellular matrix, a process that requires the assistance of the export machineries. Bioinformatic analysis revealed that the S. mutans genome contains a prsA gene, whose counterparts in other gram-positive bacteria, including Bacillus and Lactococcus, encode functions involved in protein post-export. In this study, we constructed a PrsA-deficient derivative of S. mutans and demonstrated that the prsA mutant displayed an altered cell wall/membrane protein profile as well as cell-surface-related phenotypes, including auto-aggregation, increased surface hydrophobicity and abnormal biofilm formation. Further analysis revealed that the disruption of the prsA gene resulted in reduced insoluble glucan production by cell surface localized glucosyltransferases, and mutacin as well as cell surface-display of a heterologous expressed GFP fusion to the cell surface protein SpaP. Our study suggested that PrsA in S. mutans encodes functions similar to those identified in Bacillus, and so is likely to be involved in protein post-export.

[Patient safety indicators for medication safety (AMTS-PSI): international status, transferability and validation]. / Patientensicherheitsindikatoren zur Arzneimitteltherapiesicherheit (AMTS-PSI): Internationaler Status, Übertragbarkeit und Validierung*

BACKGROUND: The aim of this project was to identify international patient safety indicators used for medication safety (AMTS-PSI), to evaluate the validity by a panel of experts, and to examine the transfer of the international AMTS-PSI to the pharmacotherapy care of the German Health Care System. It was part of the "Agenda for the Improvement of Medication Safety 2008/2009 in Germany" of the German Ministry of Health. METHOD: National and international AMTS-PSI were identified by a systematic review (Set 1). To define patient safety indicators as a subdivision of quality indicators, the indicators were categorised by patient's risk of adverse drug events and the degree of prevention (Set 2). Duplicates of AMTS-PSI were excluded (Set 3). The content validity was determined by the "qualify-instrument" on categories "relevance", "evidence" and "feasibility". This process was based on a double-stage Delphi method. The transferability to the pharmacotherapy care of the German Health Care System of the AMTS-PSI was evaluated (Set 4). RESULTS: 385 AMTS-indicators were identified. The categorisation resulted in a set of 40 AMTS-PSI, 20 AMTS-PSI were excluded. The evaluation of the validity by the "qualify-instrument" and the transferability resulted in a set of 14 for the stationary, ambulant sector. They also were valid for both sectors. CONCLUSION: An AMTS-PSI-set was identified by a systematic review and recognised as valid for transferring it to the pharmacotherapy care of the German Health Care System by the "qualify-instrument". These 14 AMTS-PSI are mainly characterised by their relevance. Before using these indicators in practice, their further operationalisation seems necessary.

Community-based interference against integration of Pseudomonas aeruginosa into human salivary microbial biofilm.

As part of the human gastrointestinal tract, the oral cavity represents a complex biological system and harbors diverse bacterial species. Unlike the gut microbiota, which is often considered a health asset, studies of the oral commensal microbiota have been largely limited to their implication in oral conditions such as dental caries and periodontal disease. Less emphasis has been given to their potential beneficial roles, especially the protective effects against oral colonization by foreign or pathogenic bacteria. In this study, we used salivary microbiota derived from healthy human subjects to investigate protective effects against colonization and integration of Pseudomonas aeruginosa, an opportunistic bacterial pathogen, into developing or pre-formed salivary biofilms. When co-cultivated in saliva medium, P. aeruginosa persisted in the planktonic phase, but failed to integrate into the salivary microbial community during biofilm formation. Furthermore, in saliva medium supplemented with sucrose, the oral microbiota inhibited the growth of P. aeruginosa by producing lactic acid. More interestingly, while pre-formed salivary biofilms were able to prevent P. aeruginosa colonization, the same biofilms recovered from mild chlorhexidine gluconate treatment displayed a shift in microbial composition and showed a drastic reduction in protection. Our study indicates that normal oral communities with balanced microbial compositions could be important in effectively preventing the integration of foreign or pathogenic bacterial species, such as P. aeruginosa.

In vitro study of biofilm formation and effectiveness of antimicrobial treatment on various dental material surfaces.

Elevated proportions of Candida albicans in biofilms formed on dentures are associated with stomatitis whereas Streptococcus mutans accumulation on restorative materials can cause secondary caries. Candida albicans, S. mutans, saliva-derived and C. albicans/saliva-derived mixed biofilms were grown on different materials including acrylic denture, porcelain, hydroxyapatite (HA), and polystyrene. The resulting biomass was analysed by three-dimensional image quantification and assessment of colony-forming units. The efficacy of biofilm treatment with a dissolved denture cleansing tablet (Polident(®)) was also evaluated by colony counting. Biofilms formed on HA exhibited the most striking differences in biomass accumulation: biofilms comprising salivary bacteria accrued the highest total biomass whereas C. albicans biofilm formation was greatly reduced on the HA surface compared with other materials, including the acrylic denture surface. These results substantiate clinical findings that acrylic dentures can comprise a reservoir for C. albicans, which renders patients more susceptible to C. albicans infections and stomatitis. Additionally, treatment efficacy of the same type of biofilms varied significantly depending on the surface. Although single-species biofilms formed on polystyrene surfaces exhibited the highest susceptibility to the treatment, the most surviving cells were recovered from HA surfaces for all types of biofilms tested. This study demonstrates that the nature of a surface influences biofilm characteristics including biomass accumulation and susceptibility to antimicrobial treatments. Such treatments should therefore be evaluated on the surfaces colonized by the target pathogen(s).

Using DGGE profiling to develop a novel culture medium suitable for oral microbial communities.

More than 700 bacterial species have been detected in the human oral cavity. They form highly organized microbial communities and are responsible for many oral infectious diseases, such as dental caries and periodontal disease. The prevention and treatment of these diseases require a comprehensive knowledge of oral microbial communities, which largely relies on culture-dependent methods to provide detailed phenotypic and physiological analysis of these communities. However, most of the currently available laboratory media can only selectively support the growth of a limited number of bacterial species within these communities, and fail to sustain the original oral microbial diversity. In this study, using denaturing gradient gel electrophoresis (DGGE) as an index to systematically survey and analyse the selectivity of commonly used laboratory media, we developed a new medium (SHI medium) by combining the ingredients of several selected media that can support different subpopulations within the original oral microbial community derived from pooled saliva. DGGE and 454 pyrosequencing analysis showed that SHI medium was capable of supporting a more diversified community with a microbial profile closer to that of the original oral microbiota. Furthermore, 454 pyrosequencing revealed that SHI medium supported the growth of many oral species that have not before been cultured. Crystal violet assay and the confocal laser scanning microscope analysis indicated that, compared with other media, SHI medium is able to support a more complex saliva-derived biofilm with higher biomass yield and more diverse species. This DGGE-guided method could also be used to develop novel media for other complex microbial communities.

Effect of glucose on Treponema denticola cell behavior.

INTRODUCTION: Treponema denticola inhabits the oral subgingival environment and is part of a proteolytic benzoyl-dl-arginine-naphthylamide-positive 'red complex' associated with active periodontal disease. Spirochetes have a unique form of chemotactic motility that may contribute to their virulence. Chemotaxis is essential for efficient nutrient-directed translocation. METHODS: We examined the effect of glucose on T. denticola cell velocity, expression of periplasmic flagella proteins, and chemotaxis, e.g. translocation into capillary tubes. RESULTS: The presence of glucose did not significantly effect T. denticola cell velocity in high viscosity conditions nor did it alter periplasmic flagella protein expression. The addition of glucose to capillary tubes resulted in greater numbers of T. denticola cells in tubes containing glucose. A non-motile mutant did not migrate into capillary tubes containing glucose. CONCLUSION: These results are consistent with a chemotactic response to glucose that is motility dependent.

[Effective prevention through nutritional and food additives: barriers and resistance]. / Bevölkerungsbezogene Etablierung präventiv wirksamer Nahrungs- und Lebensmittelzusätze: Barrieren und Widerstände.

The population-wide and individual preventive potentials of nutritional and food additives such as vitamins and trace elements are generally accepted in the international literature. Iodisation and fluoridation were and are a main focus of activity. The enrichment of food with folic acid is also partly population-related. Until now, however, the theoretical possibilities of nutritional supplementations have not been fully exploited. Various barriers and resistances arise in programme development and implementation. Interviews with key stakeholders and community groups can clarify decade-long discussions in the literature and the media. The study on hand is based on a structural analysis. It shows the various arguments as well as beneficial and impeding factors for a population-wide prevention programme, for specific target groups and individuals. The findings of this research could also be applied to other Public Health challenges.

Fusobacterium nucleatum apoptosis-inducing outer membrane protein.

The periodontal pathogen Fusobacterium nucleatum induces apoptosis in lymphocytes. We previously identified the autotransporter protein Fap2 in F. nucleatum strain PK1594 that induced apoptosis in lymphocytes when expressed in Escherichia coli. In this study, we identified protein homologs of Fap2 in the transformable F. nucleatum strain ATCC 23726, to determine their role in the induction of apoptosis in lymphocytes. We used a new gene-inactivation vector conferring thiamphenicol resistance (pHS31) to construct a mutant deficient in one of the homologs, aim1. Transcriptional analyses demonstrated disruption of aim1 expression, and phenotypic analyses revealed a 41% decrease in the ability of the mutant to induce apoptosis in Jurkat cells, as compared with the parental strain. These studies demonstrate, in the native host cell background, the contribution of aim1 to F. nucleatum induction of apoptosis and, to the best of our knowledge, represent the first report of a genetically defined and phenotypically characterized mutation in F. nucleatum.

Motility and chemotaxis in tissue penetration of oral epithelial cell layers by Treponema denticola.

The ability to penetrate tissue is an important virulence factor for pathogenic spirochetes. Previous studies have recognized the role of motility in allowing pathogenic spirochetes to invade tissues and migrate to sites favorable for bacterial proliferation. However, the nature of the movements, whether they are random or controlled by chemotaxis systems, has yet to be established. In this study, we addressed the role of motility and chemotaxis in tissue penetration by the periodontal disease-associated oral spirochete Treponema denticola using an oral epithelial cell line-based experimental approach. Wild-type T. denticola ATCC 35405 was found to penetrate the tissue layers effectively, whereas a nonmotile mutant was unable to overcome the tissue barrier. Interestingly, the chemotaxis mutants also showed impaired tissue penetration. A cheA mutant that is motile but lacks the central kinase of the chemotaxis pathway showed only about 2 to 3% of the wild-type penetration rate. The two known chemoreceptors of T. denticola, DmcA and DmcB, also appear to be involved in the invasion process. The dmc mutants were actively motile but exhibited reduced tissue penetration of about 30 and 10% of the wild-type behavior, respectively. These data suggest that not only motility but also chemotaxis is involved in the tissue penetration by T. denticola.

Determinants of chemotactic signal amplification in Escherichia coli.

A well-characterized protein phosphorelay mediates Escherichia coli chemotaxis towards the amino acid attractant aspartate. The protein CheY shuttles between flagellar motors and methyl-accepting chemoreceptor (MCP) complexes containing the linker CheW and the kinase CheA. CheA-CheY phosphotransfer generates phospho-CheY, CheY-P. Aspartate triggers smooth swim responses by inactivation of the CheA bound to the target MCP, Tar; but this mechanism alone cannot explain the observed response sensitivity. Here, we used behavioral analysis of mutants deleted for CheZ, a catalyst of CheY-P dephosphorylation, or the methyltransferase CheR and/or the methylesterase CheB to examine the roles of accelerated CheY-P dephosphorylation and MCP methylation in enhancement of the chemotactic response. The extreme motile bias of the mutants was adjusted towards wild-type values, while preserving much of the aspartate response sensitivity by expressing fragments of the MCP, Tsr, that either activate or inhibit CheA. We then measured responses to small jumps of aspartate, generated by flash photolysis of photo-labile precursors. The stimulus-response relation for Delta cheZ mutants overlapped that for the host strains. Delta cheZ excitation response times increased with stimulus size consistent with formation of an occluded CheA state. Thus, neither CheZ-dependent or independent increases in CheY-P dephosphorylation contribute to the excitation response. In Delta cheB Delta cheR or Delta cheR mutants, the dose for a half-maximal response, [Asp](50), was ca 10 microM; but was elevated to 100 microM in Delta cheB mutants. In addition, the stimulus-response relation for these mutants was linear, consistent with stoichiometric inactivation, in contrast to the non-linear relation for wild-type E. coli. These data suggest that response sensitivity is controlled by differential binding of CheR and/or CheB to distinct MCP signaling conformations.

Electrocardiographic measures of repolarization revisited: why? what? how?

Ventricular repolarization continues to be an enigma to clinical cardiologists and cardiac electrophysiologists. On the one hand, a century of experience has documented an association between abnormal T-wave morphology, QT prolongation and dispersion, T-wave alternans, and nonspecific ST-T waves with arrhythmia risk or negative prognostic outcome. On the other hand, recent advances in molecular electrophysiology have definitively implicated abnormal function and structure of cardiac ion channels associated with repolarization as primary arrhythmogenic mechanisms in long QT syndrome, Brugada's Syndrome, and idiopathic ventricular fibrillation and ventricular tachycardia. In spite of this extensive clinical experience and newly established mechanistic knowledge, robust measurements of repolarization and sensitive algorithms for reliable assessment of risk and prediction of arrhythmia occurrence have remained elusive. New insights into electrocardiographic waveform that reflect and capture the underlying spatial and dynamic characteristics of repolarization offer opportunity to devise clinical indices of repolarization that might be more predictive of risk or outcome than those currently used. Experimental and model data show evidence that the location and size of repolarization lesions may be deduced from T waveform. The changes of repolarization induced by altered activation sequence, and cycle length mediated alterations to repolarization offer additional means to assess the magnitude and significance of such lesions that are linked to increased arrhythmogenic risk. This article explores indices of repolarization that are sensitive to repolarization and its change and that provide opportunity to better characterize and assess repolarization for risk stratification.