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A body of data supports the existence of core (α2-α5) dimers of BAK and BAX in the oligomeric, membrane-perturbing conformation of these essential apoptotic effector molecules. Molecular structures for these dimers have only been captured for truncated constructs encompassing the core domain alone. Here, we report a crystal structure of BAK α2-α8 dimers (i.e., minus its flexible N-terminal helix and membrane-anchoring C-terminal segment) that has been obtained through the activation of monomeric BAK with the detergent C12E8. Core dimers are evident, linked through the crystal by contacts via latch (α6-α8) domains. This crystal structure shows activated BAK dimers with the extended latch domain present. Our data provide direct evidence for the conformational change converting BAK from inert monomer to the functional dimer that destroys mitochondrial integrity. This dimer is the smallest functional unit for recombinant BAK or BAX described so far.
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Detergentes/química , Multimerización de Proteína , Proteína Destructora del Antagonista Homólogo bcl-2/química , Secuencia de Aminoácidos , Animales , Liposomas , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Moleculares , Estructura Secundaria de Proteína , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismoRESUMEN
In stressed cells, apoptosis ensues when Bcl-2 family members Bax or Bak oligomerize and permeabilize the mitochondrial outer membrane. Certain BH3-only relatives can directly activate them to mediate this pivotal, poorly understood step. To clarify the conformational changes that induce Bax oligomerization, we determined crystal structures of BaxΔC21 treated with detergents and BH3 peptides. The peptides bound the Bax canonical surface groove but, unlike their complexes with prosurvival relatives, dissociated Bax into two domains. The structures define the sequence signature of activator BH3 domains and reveal how they can activate Bax via its groove by favoring release of its BH3 domain. Furthermore, Bax helices α2-α5 alone adopted a symmetric homodimer structure, supporting the proposal that two Bax molecules insert their BH3 domain into each other's surface groove to nucleate oligomerization. A planar lipophilic surface on this homodimer may engage the membrane. Our results thus define critical Bax transitions toward apoptosis.
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Apoptosis , Cristalografía por Rayos X , Proteína X Asociada a bcl-2/química , Secuencia de Aminoácidos , Animales , Citocromos c/metabolismo , Dimerización , Embrión de Mamíferos/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Liposomas/metabolismo , Hígado/metabolismo , Ratones , Mitocondrias/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Conformación Proteica , Estructura Terciaria de Proteína , Alineación de Secuencia , Proteína X Asociada a bcl-2/metabolismoRESUMEN
BACKGROUND: Janus kinase (JAK) inhibitors, including baricitinib, block cytokine signaling and are effective disease-modifying treatments for several autoimmune diseases. Whether baricitinib preserves ß-cell function in type 1 diabetes is unclear. METHODS: In this phase 2, double-blind, randomized, placebo-controlled trial, we assigned patients with type 1 diabetes diagnosed during the previous 100 days to receive baricitinib (4 mg once per day) or matched placebo orally for 48 weeks. The primary outcome was the mean C-peptide level, determined from the area under the concentration-time curve, during a 2-hour mixed-meal tolerance test at week 48. Secondary outcomes included the change from baseline in the glycated hemoglobin level, the daily insulin dose, and measures of glycemic control assessed with the use of continuous glucose monitoring. RESULTS: A total of 91 patients received baricitinib (60 patients) or placebo (31 patients). The median of the mixed-meal-stimulated mean C-peptide level at week 48 was 0.65 nmol per liter per minute (interquartile range, 0.31 to 0.82) in the baricitinib group and 0.43 nmol per liter per minute (interquartile range, 0.13 to 0.63) in the placebo group (P = 0.001). The mean daily insulin dose at 48 weeks was 0.41 U per kilogram of body weight per day (95% confidence interval [CI], 0.35 to 0.48) in the baricitinib group and 0.52 U per kilogram per day (95% CI, 0.44 to 0.60) in the placebo group. The levels of glycated hemoglobin were similar in the two trial groups. However, the mean coefficient of variation of the glucose level at 48 weeks, as measured by continuous glucose monitoring, was 29.6% (95% CI, 27.8 to 31.3) in the baricitinib group and 33.8% (95% CI, 31.5 to 36.2) in the placebo group. The frequency and severity of adverse events were similar in the two trial groups, and no serious adverse events were attributed to baricitinib or placebo. CONCLUSIONS: In patients with type 1 diabetes of recent onset, daily treatment with baricitinib over 48 weeks appeared to preserve ß-cell function as estimated by the mixed-meal-stimulated mean C-peptide level. (Funded by JDRF International and others; BANDIT Australian New Zealand Clinical Trials Registry number, ACTRN12620000239965.).
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Diabetes Mellitus Tipo 1 , Células Secretoras de Insulina , Inhibidores de las Cinasas Janus , Humanos , Australia , Glucemia/análisis , Automonitorización de la Glucosa Sanguínea , Péptido C/sangre , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Hemoglobina Glucada/análisis , Insulina/uso terapéutico , Inhibidores de las Cinasas Janus/efectos adversos , Inhibidores de las Cinasas Janus/farmacología , Inhibidores de las Cinasas Janus/uso terapéutico , Células Secretoras de Insulina/efectos de los fármacos , Método Doble CiegoRESUMEN
Certain BH3-only proteins transiently bind and activate Bak and Bax, initiating their oligomerization and the permeabilization of the mitochondrial outer membrane, a pivotal step in the mitochondrial pathway to apoptosis. Here we describe the first crystal structures of an activator BH3 peptide bound to Bak and illustrate their use in the design of BH3 derivatives capable of inhibiting human Bak on mitochondria. These BH3 derivatives compete for the activation site at the canonical groove, are the first engineered inhibitors of Bak activation, and support the role of key conformational transitions associated with Bak activation.
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Apoptosis/efectos de los fármacos , Proteína 11 Similar a Bcl2 , Mitocondrias , Péptidos , Proteína Destructora del Antagonista Homólogo bcl-2 , Animales , Proteína 11 Similar a Bcl2/química , Proteína 11 Similar a Bcl2/farmacología , Línea Celular Transformada , Humanos , Ratones , Mitocondrias/genética , Mitocondrias/metabolismo , Péptidos/química , Péptidos/farmacología , Unión Proteica , Relación Estructura-Actividad , Proteína Destructora del Antagonista Homólogo bcl-2/química , Proteína Destructora del Antagonista Homólogo bcl-2/genética , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismoRESUMEN
Progress in the discovery of new antiviral medicines is tempered by the rapidity with which drug-resistant variants emerge. A review of the resistance-suppressing properties of four classes of antivirals is presented: influenza virus neuraminidase inhibitors, HIV protease inhibitors, antibodies, and protein-based fusion inhibitors. The analysis supports the hypothesis that the more similar the drug is to the target's natural ligands, the higher the barrier to resistance. However, other factors, such as entropy compensation and solvent anchoring, might also be exploited for improved drug design.
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Antivirales/uso terapéutico , Diseño de Fármacos , Farmacorresistencia Viral , Animales , Antivirales/química , Antivirales/farmacología , Humanos , Virosis/tratamiento farmacológicoRESUMEN
AIMS: First-generation closed-loop automated insulin delivery improves glycaemia and psychosocial outcomes among older adults with type 1 diabetes in clinical trials. However, no study has previously assessed real-world lived experience of older adults using closed-loop therapy outside a trial environment. METHODS: Semi-structured interviews were conducted with older adults who were pre-existing insulin pump users and previously completed the OldeR Adult Closed-Loop (ORACL) randomised trial. Interviews focused on perceptions of diabetes technology use, and factors influencing decisions regarding continuation. RESULTS: Twenty-eight participants, mean age 70 years (SD 5), were interviewed at median 650 days (IQR 608-694) after their final ORACL trial visit. At interview, 23 participants (82%) were still using a commercial closed-loop system (requiring manual input for prandial insulin bolus doses). Themes discussed in interviews relating to closed-loop system use included sustained psychosocial benefits, cost and retirement considerations and usability frustrations relating to sensor accuracy and system alarms. Of the five participants who had discontinued, reasons included cost, continuous glucose monitoring-associated difficulties and usability frustrations. Cost was the largest consideration regarding continued use; most participants considered the increased ease of diabetes management to be worth the associated costs, though cost was prohibitive for some. CONCLUSIONS: Almost 2 years after completing a closed-loop clinical trial, closed-loop automated insulin delivery remains the preferred type 1 diabetes therapy for the majority of older adult participants. Chronological age is not a barrier to real-world successful use of diabetes technology. Identifying age-related barriers, and solutions, to diabetes technology use among older adults is warranted.
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Diabetes Mellitus Tipo 1 , Insulina , Humanos , Anciano , Insulina/uso terapéutico , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/psicología , Hipoglucemiantes/uso terapéutico , Automonitorización de la Glucosa Sanguínea , Glucemia , Resultado del Tratamiento , Sistemas de Infusión de Insulina , Estudios CruzadosRESUMEN
AIM: One third of Australian children diagnosed with type 1 diabetes present with life-threatening diabetic ketoacidosis (DKA) at diagnosis. Screening for early-stage, presymptomatic type 1 diabetes, with ongoing follow-up, can substantially reduce this risk (<5% risk). Several screening models are being trialled internationally, without consensus on the optimal approach. This pilot study aims to assess three models for a routine, population-wide screening programme in Australia. METHODS: An implementation science-guided pilot study to evaluate the feasibility, acceptability and costs of three screening models in children will be conducted between July 2022 and June 2024. These models are as follows: (1) Genetic risk-stratified screening using newborn heel prick dried bloodspots, followed by autoantibody testing from 11 months of age; (2) genetic risk-stratified screening of infant (6-12 months) saliva followed by autoantibody testing from 10 months of age; and (3) autoantibody screening using capillary dried bloodspots collected from children aged 2, 6 or 10 years. Cohorts for each model will be recruited from targeted geographic areas across Australia involving ≥2 states per cohort, with a recruitment target of up to 3000 children per cohort (total up to 9000 children). The primary outcome is screening uptake for each cohort. Secondary outcomes include programme feasibility, costs, parental anxiety, risk perception, satisfaction, well-being and quality of life, and health professional attitudes and satisfaction. CONCLUSIONS: This pilot is the first direct comparison of three screening implementation models for general population screening. Findings will provide evidence to inform a potential national screening programme for Australian children. TRIAL REGISTRATION: ACTRN12622000381785.
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AIMS: To examine the psychometric properties of the Diabetes Management Experiences Questionnaire (DME-Q). Adapted from the validated Glucose Monitoring Experiences Questionnaire, the DME-Q captures satisfaction with diabetes management irrespective of treatment modalities. METHODS: The DME-Q was completed by adults with type 1 diabetes as part of a randomized controlled trial comparing hybrid closed loop (HCL) to standard therapy. Most psychometric properties were examined with pre-randomization data (n = 149); responsiveness was examined using baseline and 26-week follow-up data (n = 120). RESULTS: Pre-randomization, participants' mean age was 44 ± 12 years, 52% were women. HbA1c was 61 ± 11 mmol/mol (7.8 ± 1.0%), diabetes duration was 24 ± 12 years and 47% used an insulin pump prior to the trial. A forced three-factor analysis revealed three expected domains, that is, 'Convenience', 'Effectiveness' and 'Intrusiveness', and a forced one-factor solution was also satisfactory. Internal consistency reliability was strong for the three subscales ( α range = 0.74-0.84) and 'Total satisfaction' ( α = 0.85). Convergent validity was demonstrated with moderate correlations between DME-Q 'Total satisfaction' and diabetes distress (PAID: rs = -0.57) and treatment satisfaction (DTSQ; rs = 0.58). Divergent validity was demonstrated with a weak correlation with prospective/retrospective memory (PRMQ: rs = -0.16 and - 0.13 respectively). Responsiveness was demonstrated, as participants randomized to HCL had higher 'Effectiveness' and 'Total satisfaction' scores than those randomized to standard therapy. CONCLUSIONS: The 22-item DME-Q is a brief, acceptable, reliable measure with satisfactory structural and construct validity, which is responsive to intervention. The DME-Q is likely to be useful for evaluation of new pharmaceutical agents and technologies in research and clinical settings.
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Diabetes Mellitus Tipo 1 , Adulto , Humanos , Femenino , Persona de Mediana Edad , Masculino , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Automonitorización de la Glucosa Sanguínea , Satisfacción del Paciente , Psicometría , Reproducibilidad de los Resultados , Estudios Retrospectivos , Estudios Prospectivos , Glucemia , Encuestas y CuestionariosRESUMEN
BACKGROUND AND AIMS: Automated insulin delivery (AID) improves glycaemia among people with type 1 diabetes in clinical trials and overseas real-world studies. Whether improvements are sustained beyond 12 months in the real world, and whether they occur in the Australian context, has not yet been established. We aimed to observe, up to 2 years, the effectiveness of initiating first-generation AID for type 1 diabetes management. METHODS: Retrospective, real-world, observational study using medical records, conducted across five sites in Australia. Adults with type 1 diabetes, who had AID initiated between February 2019 and December 2021, were observed for 6-24 months after initiation (until June 2022). Outcomes examined included glucose metrics assessed by glycated haemoglobin (HbA1c ) and continuous glucose monitoring (CGM), safety and therapy continuation. RESULTS: Ninety-four adults were studied (median age 39 years (interquartile range, IQR: 31-51); pre-initiation HbA1c 7.8% (7.2-8.6)). After AID initiation, HbA1c decreased by mean 0.5 percentage points (95% confidence interval (CI): -0.7 to -0.2) at 3 months (P < 0.001); CGM time in range 3.9-10.0 mmol/L increased by 11 percentage points (9-14) at 1 month (P < 0.001); these improvements were maintained up to 24 months (all P < 0.02). Median CGM time below 3.9 mmol/L was <1.5% pre- and post-AID initiation. The subgroup with pre-initiation HbA1c above 8.5% had the greatest HbA1c improvement (-1.4 percentage points (-1.8 to -1.1) at 3 months). Twelve individuals (13%) discontinued AID, predominantly citing difficulties with CGM. During the 150 person-years observed, four diabetes-related emergencies were documented: three severe hypoglycaemic events and one hyperglycaemic event without ketoacidosis. CONCLUSIONS: Early glucose improvements were observed after real-world AID initiation, sustained up to 2 years, without excess adverse events. The greatest benefits were observed among individuals with highest glycaemia before initiation. Future-generation systems with increased user-friendliness may enhance therapy continuation.
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Diabetes Mellitus Tipo 1 , Adulto , Humanos , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/epidemiología , Diabetes Mellitus Tipo 1/inducido químicamente , Insulina , Glucemia , Automonitorización de la Glucosa Sanguínea , Estudios Retrospectivos , Australia/epidemiología , Hipoglucemiantes , Sistemas de Infusión de InsulinaRESUMEN
Due to the myriad interactions between prosurvival and proapoptotic members of the Bcl-2 family of proteins, establishing the mechanisms that regulate the intrinsic apoptotic pathway has proven challenging. Mechanistic insights have primarily been gleaned from in vitro studies because genetic approaches in mammals that produce unambiguous data are difficult to design. Here we describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-xL Substitution of Glu75 in mBak (hBAK Q77) for leucine does not affect the three-dimensional structure of Bak or killing activity but reduces its affinity for Bcl-xL via loss of a single hydrogen bond. Using this mutant, we investigated the requirement for physical restraint of Bak by Bcl-xL in apoptotic regulation. In vitro, Bak(Q75L) cells were significantly more sensitive to various apoptotic stimuli. In vivo, loss of Bcl-xL binding to Bak led to significant defects in T-cell and blood platelet survival. Thus, we provide the first definitive in vivo evidence that prosurvival proteins maintain cellular viability by interacting with and inhibiting Bak.
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Apoptosis/genética , Plaquetas/citología , Linfocitos T/citología , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína bcl-X/metabolismo , Animales , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Línea Celular , Supervivencia Celular/genética , Humanos , Ratones , Ratones Endogámicos C57BL , Mutación , Unión Proteica , Conformación Proteica , Dominios Proteicos/genética , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2/genéticaRESUMEN
AIMS: Fracture risk is elevated in some type 2 diabetes patients. Bone fragility may be associated with more clinically severe type 2 diabetes, although prospective studies are lacking. It is unknown which diabetes-related characteristics are independently associated with fracture risk. In this post-hoc analysis of fracture data from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial (ISRCTN#64783481), we hypothesised that diabetic microvascular complications are associated with bone fragility. MATERIALS AND METHODS: The FIELD trial randomly assigned 9795 type 2 diabetes participants (aged 50-75 years) to receive oral co-micronised fenofibrate 200 mg (n = 4895) or placebo (n = 4900) daily for a median of 5 years. We used Cox proportional hazards models to identify baseline sex-specific diabetes-related parameters independently associated with incident fractures. RESULTS: Over 49,470 person-years, 137/6138 men experienced 141 fractures and 143/3657 women experienced 145 fractures; incidence rates for the first fracture of 4â4 (95% CI 3â8-5â2) and 7â7 per 1000 person-years (95% CI 6â5-9â1), respectively. Fenofibrate had no effect on fracture outcomes. In men, baseline macrovascular disease (HR 1â52, 95% CI 1â05-2â21, p = 0â03), insulin use (HR 1â62, HR 1â03-2â55, p = 0â03), and HDL-cholesterol (HR 2â20, 95% CI 1â11-4â36, p = 0â02) were independently associated with fracture. In women, independent risk factors included baseline peripheral neuropathy (HR 2â04, 95% CI 1â16-3â59, p = 0â01) and insulin use (HR 1â55, 95% CI 1â02-2â33, p = 0â04). CONCLUSIONS: Insulin use and sex-specific complications (in men, macrovascular disease; in women, neuropathy) are independently associated with fragility fractures in adults with type 2 diabetes.
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Complicaciones de la Diabetes , Diabetes Mellitus Tipo 2 , Fenofibrato , Fracturas Óseas , Insulinas , Adulto , Femenino , Humanos , Masculino , Complicaciones de la Diabetes/tratamiento farmacológico , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Fenofibrato/uso terapéutico , Fracturas Óseas/epidemiología , Fracturas Óseas/etiología , Fracturas Óseas/prevención & control , Insulinas/uso terapéutico , Estudios Prospectivos , Factores de RiesgoRESUMEN
AIM: To explore the lived experience of older adults with type 1 diabetes using closed-loop automated insulin delivery, an area previously receiving minimal attention. METHODS: Semi-structured interviews were conducted with adults aged 60 years or older with long-duration type 1 diabetes who participated in a randomised, open-label, two-stage crossover trial comparing first-generation closed-loop therapy (MiniMed 670G) versus sensor-augmented pump therapy. Interview recordings were transcribed, thematically analysed and assessed. RESULTS: Twenty-one older adults participated in interviews after using closed-loop therapy. Twenty were functionally independent, without frailty or major cognitive impairment; one was dependent on caregiver assistance, including for diabetes management. Quality of life benefits were identified, including improved sleep and reduced diabetes-related psychological burden, in the context of experiencing improved glucose levels. Gaps between expectations and reality of closed-loop therapy were also experienced, encountering disappointment amongst some participants. The cost was perceived as a barrier to continued closed-loop access post-trial. Usability issues were identified, such as disruptive overnight alarms and sensor inaccuracy. CONCLUSIONS: The lived experience of older adults without frailty or major cognitive impairment using first-generation closed-loop therapy was mainly positive and concordant with glycaemic benefits found in the trial. Older adults' lived experience using automated insulin delivery beyond trial environments requires exploration; moreover, the usability needs of older adults should be considered during future device development.
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Diabetes Mellitus Tipo 1 , Fragilidad , Humanos , Anciano , Insulina/uso terapéutico , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Calidad de Vida , Resultado del Tratamiento , Sistemas de Infusión de Insulina , Automonitorización de la Glucosa Sanguínea , Estudios Cruzados , GlucemiaRESUMEN
Hypoglycaemia during sleep is a common and clinically important issue for people living with insulin-treated diabetes. Continuous glucose monitoring devices can help to identify nocturnal hypoglycaemia and inform treatment strategies. However, sleep is generally inferred, with diabetes researchers and physicians using a fixed-overnight period as a proxy for sleep-wake status when analysing and interpretating continuous glucose monitoring data. No study to date has validated such an approach with established sleep measures. Continuous glucose monitoring and research-grade actigraphy devices were worn and sleep diaries completed for 2 weeks by 28 older adults (mean age 67 years [SD 5]; 17 (59%) women) with type 1 diabetes. Using continuous glucose monitoring data from a total of 356 nights, fixed-overnight (using the recommended period of 00:00â hours-06:00â hours) and objectively-measured sleep periods were compared. The fixed-overnight period approach missed a median 57 min per night (interquartile range: 49-64) of sleep for each participant, including five continuous glucose monitoring-detected hypoglycaemia episodes during objectively-measured sleep. Twenty-seven participants (96%) had at least 1â night with continuous glucose monitoring time-in-range and time-above-range discrepancies both ≥ 10 percentage points, a clinically significant discrepancy. The utility of fixed-overnight time continuous glucose monitoring as a proxy for sleep-awake continuous glucose monitoring is inadequate as it consistently excludes actual sleep time, obscures glycaemic patterns, and misses sensor hypoglycaemia episodes during sleep. The use of validated measures of sleep to aid interpretation of continuous glucose monitoring data is encouraged.
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BACKGROUND: Type 2 diabetes (T2D) is a well-recognised cardiovascular disease (CVD) risk factor, and recent guidelines for the management of T2D include consideration of CVD risk. AIM: To assess whether contemporary clinical management of Australians with T2D is in accord with recent national and international guidelines. METHODS: This Australia-specific analysis of the CAPTURE study, a non-interventional, cross-sectional study included adults diagnosed with T2D ≥180 days prior to providing informed consent and visiting primary or specialist care. Main outcome measures were the use of blood glucose-lowering medications (BGLMs), BGLMs with proven cardiovascular benefits and other CVD medications, stratified by CVD status and care setting. RESULTS: Of 824 Australian participants in the CAPTURE sample, 332 (40.3%) had CVD. Oral BGLMs were used by 83.9% of all participants, most commonly metformin (76.0%), dipeptidyl peptidase-4 inhibitors (28.8%), sodium-glucose cotransporter-2 inhibitors (SGLT2is; 21.8%) and sulfonylureas (21.7%). Insulin was used by 29.2% of participants. BGLMs with proven CV benefit were used by 22.6%; glucagon-like peptide-1 receptor agonists (GLP-1 RAs) were less commonly used than SGLT2is in all CVD groups, but these drug classes were more often prescribed in specialist than primary care (SGLT2is 25.4 vs 20.7%, GLP-1 RAs 3.2 vs 0.8% respectively). Use of non-BGLMs for CVD risk reduction appeared consistent with guidelines. CONCLUSIONS: Use of BGLMs with CVD benefits appears low in Australia, irrespective of CVD status. This likely reflects the delay in translation of clinical evidence into contemporary care and prescribing restrictions.
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Enfermedades Cardiovasculares , Diabetes Mellitus Tipo 2 , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Adulto , Humanos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/epidemiología , Hipoglucemiantes/uso terapéutico , Inhibidores del Cotransportador de Sodio-Glucosa 2/uso terapéutico , Enfermedades Cardiovasculares/diagnóstico , Estudios Transversales , Australia/epidemiología , Glucemia , Glucosa , Péptido 1 Similar al Glucagón/uso terapéuticoRESUMEN
In 6002 Australian adults with type 2 diabetes and a median 5-year follow-up in the FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) trial, baseline socioeconomic status (SES) and self-reported education level were not related to development of on-trial sight-threatening diabetic retinopathy. Similarly, in a retinal photography substudy (n = 549), two-step diabetic retinopathy progression was not related to SES or education.
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Diabetes Mellitus Tipo 2 , Retinopatía Diabética , Fenofibrato , Adulto , Humanos , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/epidemiología , Retinopatía Diabética/epidemiología , Australia/epidemiología , EscolaridadRESUMEN
Apoptosis, the intrinsic programmed cell death process, is mediated by the Bcl-2 family members Bak and Bax. Activation via formation of symmetric core dimers and oligomerization on the mitochondrial outer membrane (MOM) leads to permeabilization and cell death. Although this process is linked to the MOM, the role of the membrane in facilitating such pores is poorly understood. We recently described Bak core domain dimers, revealing lipid binding sites and an initial role of lipids in oligomerization. Here we describe simulations that identified localized clustering and interaction of triacylglycerides (TAGs) with a minimized Bak dimer construct. Coalescence of TAGs occurred beneath this Bak dimer, mitigating dimer-induced local membrane thinning and curvature in representative coarse-grain MOM and model membrane systems. Furthermore, the effects observed as a result of coarse-grain TAG cluster formation was concentration dependent, scaling from low physiological MOM concentrations to those found in other organelles. We find that increasing the TAG concentration in liposomes mimicking the MOM decreased the ability of activated Bak to permeabilize these liposomes. These results suggest that the presence of TAGs within a Bak-lipid membrane preserves membrane integrity and is associated with reduced membrane stress, suggesting a possible role of TAGs in Bak-mediated apoptosis.
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Liposomas , Proteína Destructora del Antagonista Homólogo bcl-2 , Apoptosis , Lípidos , Liposomas/metabolismo , Membranas Mitocondriales/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2/análisis , Proteína Destructora del Antagonista Homólogo bcl-2/química , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/metabolismoRESUMEN
BACKGROUND: Perioperative diabetes management has become increasingly complex; management is often inconsistent resulting in dysglycaemia and associated morbidity. AIM: To evaluate a structured pre-admission perioperative diabetes management plan (PDMP) for safe and appropriate recommendation, prescription and administration of diabetes medications in the perioperative period for people with diabetes undergoing elective, non-cardiac surgery. METHODS: A multidisciplinary team developed the intervention, a structured PDMP (including diabetes medication reconciliation, management guide, individualised plan) to standardise optimal perioperative diabetes management. A single centre prospective pre- and post-intervention pilot study was performed, including all individuals with diabetes medications attending the pre-admissions clinic during two 4-month periods (February to May) in 2016 (control period) and 2017 (intervention period). The primary outcome was appropriate recommendation, prescription and administration of diabetes medications (including insulin), according to the PDMP, in the perioperative period. Secondary outcomes measures were glycaemia. Analysis was by intention to treat. RESULTS: Control and intervention groups included 131 and 133 participants, respectively; they were well matched in clinical characteristics. The PDMP was completed correctly in 100 (75%) individuals in the intervention group. The appropriate use of diabetes medications increased from 30% in the control group to 71% in the intervention group (p < 0.001). Following the PDMP implementations, glycaemia improved in the overall perioperative period (8.7 ± 2.9 vs. 9.8 ± 3.3 mmol/L, p = 0.005) and at all time points (from admission and over entire hospital stay). CONCLUSION: A structured pre-admission perioperative diabetes management plan for elective surgery improved safe and appropriate diabetes medication use and glycaemia in the perioperative period.
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Diabetes Mellitus , Procedimientos Quirúrgicos Electivos , Glucemia , Diabetes Mellitus/tratamiento farmacológico , Procedimientos Quirúrgicos Electivos/métodos , Humanos , Proyectos Piloto , Estudios ProspectivosRESUMEN
AIMS: Islet autoantibody screening of infants and young children in the Northern Hemisphere, together with semi-annual metabolic monitoring, is associated with a lower risk of ketoacidosis (DKA) and improved glucose control after diagnosis of clinical (stage 3) type 1 diabetes (T1D). We aimed to determine if similar benefits applied to older Australians and New Zealanders monitored less rigorously. METHODS: DKA occurrence and metabolic control were compared between T1D relatives screened and monitored for T1D and unscreened individuals diagnosed in the general population, ascertained from the Australasian Diabetes Data Network. RESULTS: Between 2005 and 2019, 17,105 relatives (mean (SD) age 15.7 (10.8) years; 52% female) were screened for autoantibodies against insulin, glutamic acid decarboxylase, and insulinoma-associated protein 2. Of these, 652 screened positive to a single and 306 to multiple autoantibody specificities, of whom 201 and 215, respectively, underwent metabolic monitoring. Of 178 relatives diagnosed with stage 3 T1D, 9 (5%) had DKA, 7 of whom had not undertaken metabolic monitoring. The frequency of DKA in the general population was 31%. After correction for age, sex and T1D family history, the frequency of DKA in screened relatives was >80% lower than in the general population. HbA1c and insulin requirements following diagnosis were also lower in screened relatives, consistent with greater beta cell reserve. CONCLUSIONS: T1D autoantibody screening and metabolic monitoring of older children and young adults in Australia and New Zealand, by enabling pre-clinical diagnosis when beta cell reserve is greater, confers protection from DKA. These clinical benefits support ongoing efforts to increase screening activity in the region and should facilitate the application of emerging immunotherapies.
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Diabetes Mellitus Tipo 1 , Cetoacidosis Diabética , Cetosis , Niño , Lactante , Humanos , Femenino , Adolescente , Preescolar , Masculino , Diabetes Mellitus Tipo 1/complicaciones , Nueva Zelanda , Cetoacidosis Diabética/epidemiología , Australia , Insulina/uso terapéutico , AutoanticuerposRESUMEN
Apoptotic stimuli activate and oligomerize the proapoptotic proteins Bak and Bax, resulting in mitochondrial outer-membrane permeabilization and subsequent cell death. This activation can occur when certain BH3-only proteins interact directly with Bak and Bax. Recently published crystal structures reveal that Bax separates into core and latch domains in response to BH3 peptides. The distinguishing characteristics of BH3 peptides capable of directly activating Bax were also elucidated. Here we identify specific BH3 peptides capable of "unlatching" Bak and describe structural insights into Bak activation and oligomerization. Crystal structures and crosslinking experiments demonstrate that Bak undergoes a conformational change similar to that of Bax upon activation. A structure of the Bak core domain dimer provides a high-resolution image of this key intermediate in the pore-forming oligomer. Our results confirm an analogous mechanism for activation and dimerization of Bak and Bax in response to certain BH3 peptides.
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Fragmentos de Péptidos/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2/química , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/química , Animales , Cristalografía , Cisteína/metabolismo , Humanos , Ratones , Mitocondrias/metabolismo , Modelos Moleculares , Conformación Proteica , Multimerización de Proteína , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Proteína X Asociada a bcl-2/metabolismoRESUMEN
AIMS/HYPOTHESIS: Accurate prediction of disease progression in individuals with pre-symptomatic type 1 diabetes has potential to prevent ketoacidosis and accelerate development of disease-modifying therapies. Current tools for predicting risk require multiple blood samples taken during an OGTT. Our aim was to develop and validate a simpler tool based on a single blood draw. METHODS: Models to predict disease progression using a single OGTT time point (0, 30, 60, 90 or 120 min) were developed using TrialNet data collected from relatives with type 1 diabetes and validated in independent populations at high genetic risk of type 1 diabetes (TrialNet, Diabetes Prevention Trial-Type 1, The Environmental Determinants of Diabetes in the Young [1]) and in a general population of Bavarian children who participated in Fr1da. RESULTS: Cox proportional hazards models combining plasma glucose, C-peptide, sex, age, BMI, HbA1c and insulinoma antigen-2 autoantibody status predicted disease progression in all populations. In TrialNet, the AUC for receiver operating characteristic curves for models named M60, M90 and M120, based on sampling at 60, 90 and 120 min, was 0.760, 0.761 and 0.745, respectively. These were not significantly different from the AUC of 0.760 for the gold standard Diabetes Prevention Trial Risk Score, which requires five OGTT blood samples. In TEDDY, where only 120 min blood sampling had been performed, the M120 AUC was 0.865. In Fr1da, the M120 AUC of 0.742 was significantly greater than the M60 AUC of 0.615. CONCLUSIONS/INTERPRETATION: Prediction models based on a single OGTT blood draw accurately predict disease progression from stage 1 or 2 to stage 3 type 1 diabetes. The operational simplicity of M120, its validity across different at-risk populations and the requirement for 120 min sampling to stage type 1 diabetes suggest M120 could be readily applied to decrease the cost and complexity of risk stratification.