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1.
Artigo em Inglês | MEDLINE | ID: mdl-38722781

RESUMO

PURPOSE: To investigate whether patients with craniosynostosis exhibit higher rates of nasolacrimal duct obstruction (NLDO) and to explore potential risk factors. METHODS: Retrospective review including all craniosynostosis patients treated at both the Divisions of Ophthalmology and Plastic, Reconstructive, and Oral Surgery at The Children's Hospital of Philadelphia between 2009 and 2020 was conducted. Synostosis characteristics, lacrimal disorders, and genetic data were collected. Main outcome measures were the rate of NLDO and associations with anatomical and syndromic/genetic risk factors. RESULTS: The total of 767 participants had a mean age of 2.8 ± 3.8 years, 465 (60.6%) were males, 485 (63.2%) had no syndromic association; 631 (82.3%) had one major suture involved, 128 (17%) had involvement of 2 to 4 major sutures, and 429 (55.9%) underwent craniofacial surgery. Forty-eight (6.2%) patients had NLDO, which more prevalent in the genetic/syndromic group (11.0% vs. 3.5%, respectively, p < 0.001), with the highest prevalence observed in patients with Apert syndrome (n = 4, 30.8%). The genetic variants most associated with NLDO were EFNB1 (n = 1, 100%) and FGFR2 (n = 6, 19.4%). There was no association between NLDO and the number or types of sutures involved or a history of craniofacial surgery. CONCLUSIONS: Nasolacrimal duct obstruction is more common in patients with craniosynostosis compared to the general population. Having a putative syndrome or a putative genetic variant and female sex were risk factors for NLDO. Ophthalmic evaluations for all craniosynostosis patients and careful assessments of any symptoms of tearing are recommended.

2.
Adv Exp Med Biol ; 1447: 21-35, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38724781

RESUMO

The pathophysiology of atopic dermatitis is complex and multifactorial, involving elements of barrier dysfunction, alterations in cell-mediated immune responses, IgE-mediated hypersensitivity, and environmental factors. Loss-of-function mutations in filaggrin have been implicated in severe atopic dermatitis due to a potential increase in trans-epidermal water loss, pH alterations, and dehydration. Other genetic changes have also been identified, which may alter the skin's barrier function, resulting in an atopic dermatitis phenotype. The imbalance of Th2 to Th1 cytokines observed in atopic dermatitis can create alterations in the cell-mediated immune responses and can promote IgE-mediated hypersensitivity, both of which appear to play a role in the development of atopic dermatitis. One must additionally take into consideration the role of the environment on the causation of atopic dermatitis and the impact of chemicals such as airborne formaldehyde, harsh detergents, fragrances, and preservatives. Use of harsh alkaline detergents in skin care products may also unfavorably alter the skin's pH causing downstream changes in enzyme activity and triggering inflammation. Environmental pollutants can trigger responses from both the innate and adaptive immune pathways. This chapter will discuss the multifaceted etiology of atopic dermatitis, which will help us to elucidate potential therapeutic targets. We will also review existing treatment options and their interaction with the complex inflammatory and molecular triggers of atopic dermatitis.


Assuntos
Dermatite Atópica , Proteínas Filagrinas , Dermatite Atópica/imunologia , Dermatite Atópica/genética , Dermatite Atópica/fisiopatologia , Humanos , Pele/patologia , Pele/imunologia , Animais , Citocinas/metabolismo , Imunoglobulina E/imunologia , Exposição Ambiental/efeitos adversos
3.
Menopause ; 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38743907

RESUMO

OBJECTIVE: The aim of the study is to identify appropriate definitions and patient-reported outcome measures (PROMs) for each of the eight core outcomes previously selected for genitourinary symptoms associated with menopause: pain with sex, vulvovaginal dryness, vulvovaginal discomfort or irritation, discomfort or pain when urinating, change in most bothersome symptom, distress, bother or interference of genitourinary symptoms, satisfaction with treatment, and side effects. METHODS: We conducted a systematic review to identify possible definitions and PROMs, including their measurement properties. Identified definitions and relevant PROMs with acceptable measurement properties were entered into an international consensus process involving 28 participants from 10 countries to achieve final recommendations for each core outcome. RESULTS: A total of 87 publications reporting on 34 PROMs were identified from 21,207 publications screened. Of these 34 PROMs, 29 were not considered to sufficiently map onto the core outcomes, and 26 of these also had insufficient measurement properties. Therefore, only five PROMs corresponding to two core outcomes were considered for recommendation. We recommend the PROMIS Scale v2.0 - Sexual Function and Satisfaction: Vaginal Discomfort with Sexual Activity to measure the outcome of "pain with sexual activity" and the Day-to-Day Impact of Vaginal Aging (DIVA) Questionnaire to measure "distress, bother or interference" from genitourinary symptoms. Six definitions of "side effects" were identified and considered. We recommend that all trials report adverse events in study participants, which is a requirement of Good Clinical Practice. CONCLUSIONS: Suitable PROMs and definitions were identified to measure three of eight core outcomes. Because of the lack of existing measures, which align with the core outcomes and have evidence of high-quality measurement properties, future work will focus on developing or validating PROMs for the remaining five core outcomes.

5.
bioRxiv ; 2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38746337

RESUMO

A key challenge for single cell discovery analysis is to identify new cell types, describe them quantitatively, and seek these novel cells in new studies often using a different platform. Over the last decade, tools were developed to address identification and quantitative description of cells in human tissues and tumors. However, automated validation of populations at the single cell level has struggled due to the cytometry field's reliance on hierarchical, ordered use of features and on platform-specific rules for data processing and analysis. Here we present Velociraptor, a workflow that implements Marker Enrichment Modeling in three cross-platform modules: 1) identification of cells specific to disease states, 2) description of hallmark features for each cell and population, and 3) searching for cells matching one or more hallmark feature sets in a new dataset. A key advance is that Velociraptor registers cells between datasets, including between flow cytometry and quantitative imaging using different, overlapping feature sets. Four datasets were used to challenge Velociraptor and reveal new biological insights. Working at the individual sample level, Velociraptor tracked the abundance of clinically significant glioblastoma brain tumor cell subsets and characterized the cells that predominate in recurrent tumors as a close match for rare, negative prognostic cells originally observed in matched pre-treatment tumors. In patients with inborn errors of immunity, Velociraptor identified genotype-specific cells associated with GATA2 haploinsufficiency. Finally, in cross-platform analysis of immune cells in multiplex imaging of breast cancer, Velociraptor sought and correctly identified memory T cell subsets in tumors. Different phenotypic descriptions generated by algorithms or humans were shown to be effective as search inputs, indicating that cell identity need not be described in terms of per-feature cutoffs or strict hierarchical analyses. Velociraptor thus identifies cells based on hallmark feature sets, such as protein expression signatures, and works effectively with data from multiple sources, including suspension flow cytometry, imaging, and search text based on known or theoretical cell features.

7.
Clin Infect Dis ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38728385

RESUMO

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and RNA debris persist in viral reservoirs for weeks to months following infection, potentially triggering interferon production and chronic inflammation. RSLV-132 is a biologic drug composed of catalytically active human RNase1 fused to human IgG1 Fc and is designed to remain in circulation and digest extracellular RNA. We hypothesized that removal of SARS-CoV-2 viral RNA from latent reservoirs may improve inflammation, neuroinflammation, and fatigue associated with post-acute sequelae of SARS-CoV-2 infection (PASC). METHODS: This was a phase 2, double-blind, placebo-controlled randomized clinical trial in participants with a 24-week history of PASC and severe fatigue. The primary endpoint of the trial assessed the impact of 6 intravenous doses of RSLV-132 on the mean change from baseline at day 71 in the Patient-Reported Outcomes Measurement Information System Fatigue Short Form 7a (PROMIS Fatigue SF 7a). RESULTS: A statistically significant difference on day 71 was not observed with respect to the primary or secondary endpoints. This was likely due to a placebo response that increased during the trial. Statistically significant improvement in fatigue as measured by the PROMIS Fatigue SF 7a, Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue), and Physicians Global Assessment (PGA) instruments were observed earlier in the trial, with women demonstrating greater responses to RSLV-132 than men. CONCLUSION: While fatigue was not statistically significantly improved at Day 71, earlier timepoints revealed statistically significant improvement in fatigue and physician global assessment. The data suggest eliminating latent viral RNA by increasing serum RNase activity may improve fatigue in PASC patients. Women may respond better to this approach than men. Future studies will aim to confirm these findings.

8.
Stress Health ; : e3417, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38728433

RESUMO

It is well established that university students are vulnerable to poor mental health. Although increased gratitude has been shown to reduce stress among students, a clearer understanding of key mechanisms underpinning this relationship are needed to better inform theoretical models and potential interventions targeted at improving well-being in university students. The present study provides the first direct test of whether capacity for emotion regulation mediates the relationship of gratitude with stress at the beginning and middle of the academic semester. This study is also the first to assess this relationship in a cross-lagged panel mediation model. We used a repeated measures design and a total of 343 undergraduate students completed two online surveys with validated measures of gratitude, stress, and emotion regulation-one at the beginning and the second in the middle of the academic semester. Results showed that emotion regulation mediated the relationship between gratitude and stress at the beginning of semester, and again 6 weeks later. A Clogg's z-score test suggested that the strength of the indirect effect significantly increased across the two time points. A post-hoc cross-lagged panel model found that high gratitude at the beginning of the semester predicted low stress in the middle of the semester via emotion regulation. These data provide novel evidence that emotion regulation may serve as a key protective factor against undergraduate stress. The results provide evidence to support leading theories on how gratitude can reduce stress and promote well-being in university students. They also highlight the practical importance of strengthening emotion regulation abilities in university students and can be used to inform future targeted interventions to improve well-being in university students.

9.
Perfusion ; : 2676591241253464, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730556

RESUMO

BACKGROUND: The use of extracorporeal life support (ECLS) in patients after surgical repair for acute type A aortic dissection (ATAAD) has not been well documented. METHODS: We performed a systematic review and meta-analysis to assess the outcomes of ECLS after surgery for ATAAD with data published by October 2023 in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines. The protocol was registered in PROSPERO (CRD42023479955). RESULTS: Twelve observational studies met our eligibility criteria, including 280 patients. Mean age was 55.0 years and women represented 25.3% of the overall population. Although the mean preoperative left ventricle ejection fraction was 59.8%, 60.8% of patients developed left ventricle failure and 34.0% developed biventricular failure. Coronary involvement and malperfusion were found in 37.1% and 25.6%, respectively. Concomitant coronary bypass surgery was performed in 38.5% of patients. Regarding ECLS, retrograde flow (femoral) was present in 39.9% and central cannulation was present in 35.4%. In-hospital mortality was 62.8% and pooled estimate of successful weaning was 50.8%. Neurological complications, bleeding and renal failure were found in 25.9%, 38.7%, and 65.5%, respectively. CONCLUSION: ECLS after surgical repair for ATAAD remains associated with high rates of in-hospital death and complications, but it still represents a chance of survival in critical situations. ECLS remains a salvage attempt and surgeons should not try to avoid ECLS at all costs after repairing an ATAAD case.

10.
Lancet Respir Med ; 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38734022

RESUMO

BACKGROUND: Tuberculosis is a preventable disease. However, there is debate regarding which individuals would benefit most from tuberculosis preventive treatment and whether these benefits vary in settings with a high burden and low burden of tuberculosis. We aimed to compare the effectiveness of tuberculosis preventive treatment in exposed individuals of differing ages and Mycobacterium tuberculosis infection status while considering tuberculosis burden of the settings. METHODS: In this systematic review and individual-participant meta-analysis, we investigated the development of incident tuberculosis in people closely exposed to individuals with tuberculosis. We searched for studies published between Jan 1, 1998, and April 6, 2018, in MEDLINE, Web of Science, BIOSIS, and Embase. We restricted our search to cohort studies; case-control studies and outbreak reports were excluded. Two reviewers evaluated titles, abstracts, and full text articles for eligibility. At each stage, two reviewers discussed discrepancies and re-evaluated articles until a consensus was reached. Individual-participant data and a pre-specified list of variables, including characteristics of the exposed contact, the index patient, and environmental characteristics, were requested from authors of all eligible studies; contacts exposed to a drug-resistant tuberculosis index patient were excluded. The primary study outcome was incident tuberculosis. We estimated adjusted hazard ratios (aHRs) for incident tuberculosis with mixed-effects Cox regression models with a study-level random effect. We estimated the number-needed-to-treat (NNT) to prevent one person developing tuberculosis. Propensity score matching procedures were used in all analyses. This study is registered with PROSPERO (CRD42018087022). FINDINGS: After screening 25 358 records for eligibility, 439 644 participants from 32 cohort studies were included in the individual-participant data meta-analysis. Participants were followed for 1 396 413 person-years (median of 2·7 years [IQR 1·3-4.4]), during which 2496 people were diagnosed with incident tuberculosis. Overall, effectiveness of preventive treatment was 49% (aHR 0·51 [95% CI 0·44-0·60]). Participants with a positive tuberculin-skin-test (TST) or IFNγ release assay (IGRA) result at baseline benefitted from greater protection, regardless of age (0·09 [0·05-0·17] in children younger than 5 years, 0·20 [0·15-0·28] in individuals aged 5-17 years, and 0·17 [0·13-0·22] in adults aged 18 years and older). The effectiveness of preventive treatment was greater in high-burden (0·31 [0·23-0·40]) versus low-burden (0·58 [0·47-0·72]) settings. The NNT ranged from 9 to 34 depending on age among participants with a positive TST or IGRA in both high-burden and low-burden settings; among all contacts (regardless of TST or IGRA test result), the NNT ranged from 29 to 43 in high-burden settings and 213 to 455 in low-burden settings. INTERPRETATION: Our findings suggest that a risk-targeted strategy prioritising contacts with evidence of M tuberculosis infection might be indicated in low-burden settings, and a broad approach including all contacts should be considered in high-burden settings. Preventive treatment was similarly effective among contacts of all ages. FUNDING: None.

11.
Mol Ther ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38734903

RESUMO

Sepsis is a life-threatening process due to organ dysfunction resulting from severe infections. Mesenchymal stromal cells (MSCs) are being investigated as therapy for sepsis, along with conditioning regimens to improve their function. Carbon monoxide (CO) gas, which is cytoprotective at low doses, induces autophagy and is a mediator of inflammation. We evaluated CO-induced autophagy in human(h) MSCs, and its impact on cell function in murine cecal ligation and puncture. Conditioning of hMSCs with CO ex vivo resulted in enhanced survival and bacterial clearance in vivo, and neutrophil phagocytosis of bacteria in vitro. Decreased neutrophil infiltration and less parenchymal cell death in organs were associated with increased macrophage efferocytosis of apoptotic neutrophils, promoting resolution of inflammation. These CO effects were lost when the cells were exposed to autophagy inhibition prior to gas exposure. When assessing paracrine actions of CO-induced autophagy, extracellular vesicles (EVs) were predominantly responsible. CO had no effect on EV production, but altered their miRNA cargo. Increased expression of miR-145-3p and miR-193a-3p by CO was blunted with disruption of autophagy, and inhibitors of these miRNAs led to a loss of neutrophil phagocytosis and macrophage efferocytosis. Collectively, CO-induced autophagy enhanced hMSC function during sepsis via paracrine actions of MSC-derived EVs.

12.
Appetite ; 199: 107393, 2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38705518

RESUMO

Past work suggested that psychological stress, especially in the context of relationship stress, is associated with increased consumption of energy-dense food and when maintained for long periods of time, leads to adverse health consequences. Furthermore, this association is moderated by a variety of factors, including emotional over-eating style. That being said, few work utilized a dynamical system approach to understand the intraindividual and interindividual fluctuations within this process. The current study utilized a 14-day daily diary study, collected between January-March 2020, where participants reported their partner's negative relationship behavior and their own snacking behavior. A differential equation model was applied to the daily dairy data collected. Results showed that snacking behavior followed an undamped oscillator model while negative relationship behavior followed a damped coupled oscillator model. In other words, snacking behavior fluctuated around an equilibrium but was not coupled within dyadic partners. Negative relationship behavior fluctuated around an equilibrium and was amplified over time, coupled within dyadic partners. Furthermore, we found a two-fold association between negative relationship behavior and snacking: while the association between the displacement of negative relationship behavior and snacking was negative, change in negative relationship behavior and snacking were aligned. Thus, at any given time, one's snacking depends both on the amount of negative relationship behaviors one perceives and the dynamical state a dyad is engaging in (i.e., whether the negative relationship behavior is "exacerbating" or "resolving"). This former association was moderated by emotional over-eating style and the latter association was not. The current findings highlight the importance of examining dynamics within dyadic system and offers empirical and methodological insights for research in adult relationships.

13.
Diabet Med ; : e15340, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38741266

RESUMO

AIMS: Impaired awareness of hypoglycaemia (IAH) increases the risk of severe hypoglycaemia in people with type 1 diabetes mellitus (T1DM). IAH can be reversed through meticulous avoidance of hypoglycaemia. Diabetic autonomic neuropathy (DAN) has been proposed as an underlying mechanism contributing to IAH; however, data are inconsistent. The aim of this study was to examine the effects of cardiac autonomic neuropathy (CAN) on IAH reversibility inT1DM. METHODS: Participants with T1DM and IAH (Gold score ≥4) recruited to the HypoCOMPaSS (24-week 2 × 2 factorial randomised controlled) trial were included. All underwent screening for cardiac autonomic function testing at baseline and received comparable education and support aimed at avoiding hypoglycaemia and improving hypoglycaemia awareness. Definite CAN was defined as the presence of ≥2 abnormal cardiac reflex tests. Participants were grouped according to their CAN status, and changes in Gold score were compared. RESULTS: Eighty-three participants (52 women [62.7%]) were included with mean age (SD) of 48 (12) years and mean HbA1c of 66 (13) mmol/mol (8.2 [3.3] %). The mean duration of T1DM was 29 (13) years. The prevalence of CAN was low with 5/83 (6%) participants having definite autonomic neuropathy with 11 (13%) classified with possible/early neuropathy. All participants, regardless of the autonomic function status, showed a mean improvement in Gold score of ≥1 (mean improvement -1.2 [95% CI -0.8, -1.6]; p < 0.001). CONCLUSIONS: IAH can be improved in people with T1DM, and a long duration of disease, with and without cardiac autonomic dysfunction. These data suggest that CAN is not a prime driver for modulating IAH reversibility.

14.
World Neurosurg ; 185: e57-e74, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38741330

RESUMO

BACKGROUND: Nigeria has an inadequate number of neurosurgeons to meet the population's demand for neurosurgical care. Furthermore, few Nigerian neurosurgeons are female. This study sought to evaluate perceived barriers to pursuing neurosurgery among Nigerian trainees. METHODS: A 60-question survey was distributed electronically to medical students at the College of Medicine, University of Ibadan, and unspecialized intern physicians at the University College Hospital, Ibadan, Nigeria. Participation was voluntary. RESULTS: One hundred fifty-seven respondents participated in the survey. A greater proportion of males indicated an interest in neurosurgery than females (40% vs. 18%, P = 0.010). Over 75% of respondents identified decreased family and personal time, long work hours, and limited access to maternity or paternity leave as potential barriers to neurosurgery, with no differences by gender. Respondents overall saw being female and low-income as disadvantageous to pursuing neurosurgery in Nigeria. Although they universally viewed research as important in neurosurgery, 59% of respondents reported inadequate access to research opportunities; this did not vary by gender. However, 65% of female respondents reported that having a female neurosurgery mentor would increase their interest in neurosurgery (vs. 37% of males, P = 0.001). CONCLUSIONS: Nigerian medical trainees perceived the time commitment of neurosurgery as a major barrier to pursuing the specialty. Regardless of gender, they also reported low exposure to neurosurgery and inadequate access to research and mentorship opportunities. However, we found that enhanced female representation among neurosurgery mentors and improved work-life balance could increase interest in neurosurgery and help expand Nigeria's neurosurgical workforce.


Assuntos
Escolha da Profissão , Neurocirurgia , Estudantes de Medicina , Humanos , Nigéria , Feminino , Masculino , Neurocirurgia/educação , Estudantes de Medicina/psicologia , Estudos Transversais , Adulto , Inquéritos e Questionários , Médicos/psicologia , Neurocirurgiões , Adulto Jovem
15.
N Engl J Med ; 390(19): 1742-1743, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38738761

Assuntos
Humanos
16.
Sci Rep ; 14(1): 11337, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760402

RESUMO

Verifying the quality of a random number generator involves performing computationally intensive statistical tests on large data sets commonly in the range of gigabytes. Limitations on computing power can restrict an end-user's ability to perform such verification. There are also random number-based applications where an honest user needs to publicly demonstrate that the random bits they are using pass the statistical tests without the bits being revealed. Here, we report the implementation of an entanglement-based protocol that allows a third party to publicly perform statistical tests without compromising the privacy of the random bits.

17.
Exp Physiol ; 2024 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-38763158

RESUMO

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.

19.
Int J Sport Nutr Exerc Metab ; : 1-9, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38763509

RESUMO

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.

20.
Br J Pharmacol ; 2024 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-38763521

RESUMO

BACKGROUND AND PURPOSE: The canonical Kir6.2/SUR2A ventricular KATP channel is highly ATP-sensitive and remains closed under normal physiological conditions. These channels activate only when prolonged metabolic compromise causes significant ATP depletion and then shortens the action potential to reduce contractile activity. Pharmacological activation of KATP channels is cardioprotective, but physiologically, it is difficult to understand how these channels protect the heart if they only open under extreme metabolic stress. The presence of a second KATP channel population could help explain this. Here, we characterise the biophysical and pharmacological behaviours of a constitutively active Kir6.1-containing KATP channel in ventricular cardiomyocytes. EXPERIMENTAL APPROACH: Patch-clamp recordings from rat ventricular myocytes in combination with well-defined pharmacological modulators was used to characterise these newly identified K+ channels. Action potential recording, calcium (Fluo-4) fluorescence measurements and video edge detection of contractile function were used to assess functional consequences of channel modulation. KEY RESULTS: Our data show a ventricular K+ conductance whose biophysical characteristics and response to pharmacological modulation were consistent with Kir6.1-containing channels. These Kir6.1-containing channels lack the ATP-sensitivity of the canonical channels and are constitutively active. CONCLUSION AND IMPLICATIONS: We conclude there are two functionally distinct populations of ventricular KATP channels: constitutively active Kir6.1-containing channels that play an important role in fine-tuning the action potential and Kir6.2/SUR2A channels that activate with prolonged ischaemia to impart late-stage protection against catastrophic ATP depletion. Further research is required to determine whether Kir6.1 is an overlooked target in Comprehensive in vitro Proarrhythmia Assay (CiPA) cardiac safety screens.

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