Liu, Jiankang

Abstract Although structures of vitrified supramolecular complexes have been determined at near-atomic resolution, elucidating in situ molecular structure in living cells remains a major challenge. Here, we apply a novel but simple liquid-cell technique, developed previously for real-time imaging of the dynamics at a liquid-gas interface, to image wet biological samples. With extra scattering from the liquid phase, the transmission electron micrographs show amplitude contrast comparable to that in negatively stained samples. Single-molecule domains are resolved in the protein complex GroEL imaged in buffer solution at room temperature. Moreover, various stages of virus cell entry, which are transient events with very few structural information to date, are also captured. Morphological details are reconstructed using the technique of individual particle electron tomography. These results demonstrate that this approach can be a valuable yet cost-effective technique complementary to other microscopy techniques for addressing important biological questions at the molecular level.

Aim There is an association between heart failure with preserved ejection fraction (HFpEF) and insulin resistance, but less is known about the diabetic continuum, and in particular about pre‐diabetes, in HFpEF. We examined characteristics and outcomes of participants with diabetes or pre‐diabetes in PARAGON‐HF. Methods and results Patients aged ≥50 years with left ventricular ejection fraction ≥45%, structural heart disease and elevated N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) were eligible. Patients were classified according to glycated haemoglobin (HbA1c): (i) normal HbA1c, <6.0%; (ii) pre‐diabetes, 6.0%–6.4%; (iii) diabetes, ≥6.5% or history of diabetes. The primary outcome was a composite of cardiovascular (CV) death and total heart failure hospitalizations (HFH). Of 4796 patients, 50% had diabetes and 18% had pre‐diabetes. Compared to patients with normal HbA1c, patients with pre‐diabetes and diabetes more often were obese, had a history of myocardial infarction and had lower Kansas City Cardiomyopathy Questionnaire scores, while patients with diabetes had more clinical evidence of congestion, but similar NT‐proBNP concentrations. The risks of the primary composite outcome (rate ratio [RR] 1.59, 95% confidence interval [CI] 1.35–1.88), total HFH (RR 1.67, 95% CI 1.39–2.02) and CV death (hazard ratio [HR] 1.35, 95% CI 1.07–1.71) were higher among patients with diabetes, compared to those with normal HbA1c. Patients with pre‐diabetes had a higher risk (which was intermediate between that of patients with diabetes and those with normal HbA1c) of the primary outcome (HR 1.27, 95% CI 1.00–1.60) and HFH (HR 1.35, 95% CI 1.03–1.77), but not of CV death (HR 1.02, 95% CI 0.75–1.40). Patients with diabetes treated with insulin had worse outcomes than those not, and those with ‘lean diabetes’ had similar mortality rates to those with a higher body mass index, but lower rates of HFH. Conclusion Pre‐diabetes is common in patients with HFpEF and is associated with worse clinical status and greater risk of HFH. Clinical Trial Registration: ClinicalTrials.gov Identifier NCT01920711.

Background: Heart failure with preserved ejection fraction (HFpEF) is a global public health problem with important regional differences. We investigated these differences in the PARAGON-HF trial (Prospective Comparison of Angiotensin Receptor Neprilysin Inhibitor With Angiotensin Receptor Blocker Global Outcomes in HFpEF), the largest and most inclusive global HFpEF trial. Methods: We studied differences in clinical characteristics, outcomes, and treatment effects of sacubitril/valsartan in 4796 patients with HFpEF from the PARAGON-HF trial, grouped according to geographic region. Results: Regional differences in patient characteristics and comorbidities were observed: patients from Western Europe were oldest (mean 75±7 years) with the highest prevalence of atrial fibrillation/flutter (36%); Central/Eastern European patients were youngest (mean 71±8 years) with the highest prevalence of coronary artery disease (50%); North American patients had the highest prevalence of obesity (65%) and diabetes (49%); Latin American patients were younger (73±9 years) and had a high prevalence of obesity (53%); and Asia-Pacific patients had a high prevalence of diabetes (44%), despite a low prevalence of obesity (26%). Rates of the primary composite end point of total hospitalizations for HF and death from cardiovascular causes were lower in patients from Central Europe (9 per 100 patient-years) and highest in patients from North America (28 per 100 patient-years), which was primarily driven by a greater number of total hospitalizations for HF. The effect of treatment with sacubitril-valsartan was not modified by region (interaction P >0.05). Conclusions: Among patients with HFpEF recruited worldwide in PARAGON-HF, there were important regional differences in clinical characteristics and outcomes, which may have implications for the design of future clinical trials. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01920711.