Sex-based differences in short- and longer-term diet-induced metabolic heart disease

Sex-based differences in the development of obesity-induced cardiometabolic dysfunction are well documented, however, the specific mechanisms are not completely understood. Obesity has been linked to dysregulation of the epitranscriptome, but the role of N6-methyladenosine (m6A) RNA methylation has not been investigated in relation to the sex differences during obesity-induced cardiac dysfunction. In the current study, male and female C57BL/6J mice were subjected to short- and long-term high-fat/high-sucrose (HFHS) diet to induce obesogenic stress. Cardiac echocardiography showed males developed systolic and diastolic dysfunction after 4 mo of diet, but females maintained normal cardiac function despite both sexes being metabolically dysfunctional. Cardiac m6A machinery gene expression was differentially regulated by duration of HFHS diet in male, but not female mice, and left ventricular ejection fraction correlated with RNA machinery gene levels in a sex- and age-dependent manner. RNA-sequencing of cardiac transcriptome revealed that females, but not males may undergo protective cardiac remodeling early in the course of obesogenic stress. Taken together, our study demonstrates for the first time that cardiac RNA methylation machinery genes are regulated early during obesogenic stress in a sex-dependent manner and may play a role in the sex differences observed in cardiometabolic dysfunction.NEW & NOTEWORTHY Sex differences in obesity-associated cardiomyopathy are well documented but incompletely understood. We show for the first time that RNA methylation machinery genes may be regulated in response to obesogenic diet in a sex- and age-dependent manner and levels may correspond to cardiac systolic function. Our cardiac RNA-seq analysis suggests female, but not male mice may be protected from cardiac dysfunction by a protective cardiac remodeling response early during obesogenic stress.

Optimal antiseptic skin preparation agents for minimizing surgical site infection following surgery: cost and cost-effectiveness analysis

BACKGROUND

The application of antiseptic skin agents prior to incision minimizes the rate of surgical site infection. Despite their ubiquity, the optimal skin preparation agent remains uncertain. A retrospective economic analysis was conducted to complement the results from the NEWSkin Prep trial which prospectively compared three preparation agents.

METHODS

A cost and cost-effectiveness analysis was performed from a healthcare service perspective to compare chlorhexidine with 70% ethanol, and aqueous povidone-iodine, against povidone-iodine with 70% ethanol. Resource use estimates accounted for hospital admissions, readmissions associated with surgical site infection, outpatient and general practitioner attendances, visits from community nurses and therapeutic consumables. The measure of effectiveness comprised the net difference in number of patients with surgical site infections per 1000 patients. Costs were compared using a two-sample Welch's t-test. Deterministic and probabilistic sensitivity analyses were performed to evaluate the incremental cost-effectiveness ratio.

RESULTS

The null hypothesis that the mean costs for the trial arms were significantly different was not rejected (Welch's t-test P value: 0.771 for chlorhexidine with 70% ethanol against povidone-iodine with 70% ethanol; and 0.955 for aqueous povidone-iodine against povidone-iodine with 70% ethanol). Based on bootstrap averages, the chlorhexidine with 70% ethanol intervention generated 8.0 fewer surgical site infections per 1000 patients and net cost savings of €151,698 (Euros) per 1000 patients compared with povidone-iodine with 70% ethanol, and aqueous povidone-iodine produced a net cost saving of €37,494 per 1000 patients but generated an additional 11.6 surgical site infections per 1000 patients compared with povidone-iodine with 70% ethanol. The comparison of chlorhexidine with 70% ethanol to povidone-iodine with 70% ethanol was sensitive to the inclusion of cost outliers, while the comparison of aqueous povidone-iodine to povidone-iodine with 70% ethanol was sensitive to the estimated cost per surgical site infection.

CONCLUSION

Based on the outcomes from the NEWSkin Prep study, this economic analysis found no definitive evidence in favour of any one of the study comparators. Future model-based economic analyses of alternative skin preparations should critically address the quality of evidence and integrate the results from the NEWSkin Prep study.

Fibulin-3 is necessary to prevent cardiac rupture following myocardial infarction

Despite the high prevalence of heart failure in the western world, there are few effective treatments. Fibulin-3 is a protein involved in extracellular matrix (ECM) structural integrity, however its role in the heart is unknown. We have demonstrated, using single cell RNA-seq, that fibulin-3 was highly expressed in quiescent murine cardiac fibroblasts, with expression highest prior to injury and late post-infarct (from ~ day-28 to week-8). In humans, fibulin-3 was upregulated in left ventricular tissue and plasma of heart failure patients. Fibulin-3 knockout (Efemp1-/-) and wildtype mice were subjected to experimental myocardial infarction. Fibulin-3 deletion resulted in significantly higher rate of cardiac rupture days 3-6 post-infarct, indicating a weak and poorly formed scar, with severe ventricular remodelling in surviving mice at day-28 post-infarct. Fibulin-3 knockout mice demonstrated less collagen deposition at day-3 post-infarct, with abnormal collagen fibre-alignment. RNA-seq on day-3 infarct tissue revealed upregulation of ECM degradation and inflammatory genes, but downregulation of ECM assembly/structure/organisation genes in fibulin-3 knockout mice. GSEA pathway analysis showed enrichment of inflammatory pathways and a depletion of ECM organisation pathways. Fibulin-3 originates from cardiac fibroblasts, is upregulated in human heart failure, and is necessary for correct ECM organisation/structural integrity of fibrotic tissue to prevent cardiac rupture post-infarct.