Increasing evidence links mannan-binding lectin (MBL) to late vascular complications of diabetes. MBL is a complement-activating pattern recognition molecule of the innate immune system that can mediate an inflammation response through activation of the lectin pathway. In two recent animal studies, we have shown that autoreactivity of MBL is increased in the kidney in diabetic nephropathy. We hypothesize that long-term exposure to uncontrolled high blood glucose in diabetes may mediate formation of neoepitopes in several tissues and that MBL is able to recognize these structures and thus activate the lectin pathway. To test this hypothesis, we induced diabetes by injection of low-dose streptozotocin in MBL double-knockout (MBL/DKO) mice. Development of diabetes was followed by measurements of blood glucose and urine albumin-to-creatinine ratio. Fluorophore-labelled recombinant MBL was injected intravenously in diabetic and nondiabetic mice followed by ex vivo imaging of several organs. We observed that MBL accumulated in the heart, liver, brain, lung, pancreas, and intestines of diabetic mice. We furthermore detected increased systemic complement activation after administration of MBL, thus indicating MBL-mediated systemic complement activation in these animals. These new findings indicate a global role of MBL during late diabetes-mediated vascular complications in various tissues.

Aims The present study aimed to determine the association between Type 2 diabetes mellitus (T2DM) and third-degree (complete) atrioventricular block. Methods and results This nationwide nested case–control study included patients older than 18 years, diagnosed with third-degree atrioventricular block between 1 July 1995 and 31 December 2018. Data on medication, comorbidity, and outcomes were collected from Danish registries. Five controls, from the risk set of each case of third-degree atrioventricular block, were matched on age and sex to fit a Cox regression model with time-dependent exposure and time-dependent covariates. Subgroup analysis was conducted with Cox regression models for each subgroup. We located 25 995 cases with third-degree atrioventricular block that were matched with 130 004 controls. The mean age was 76 years and 62% were male. Cases had more T2DM (21% vs. 11%), hypertension (69% vs. 50%), atrial fibrillation (25% vs. 10%), heart failure (20% vs. 6.3%), and myocardial infarction (19% vs. 9.2%), compared with the control group. In Cox regression analysis, adjusting for comorbidities and atrioventricular nodal blocking agents, T2DM was significantly associated with third-degree atrioventricular block (hazard ratio: 1.63, 95% confidence interval: 1.57–1.69). The association remained in several subgroup analyses of diseases also suspected to be associated with third-degree atrioventricular block. There was a significant interaction with comorbidities of interest including hypertension, atrial fibrillation, heart failure, and myocardial infarction. Conclusion In this nationwide study, T2DM was associated with a higher rate of third-degree atrioventricular block compared with matched controls. The association remained independent of atrioventricular nodal blocking agents and other comorbidities known to be associated with third-degree atrioventricular block.

Aims We studied the effect of discontinuing beta-blockers following myocardial infarction in comparison to continuous beta-blocker use in optimally treated, stable patients without heart failure. Methods and results Using nationwide registers, we identified first-time myocardial infarction patients treated with beta-blockers following percutaneous coronary intervention or coronary angiography. The analysis was based on landmarks selected as 1, 2, 3, 4, and 5 years after the first redeemed beta-blocker prescription date. The outcomes included all-cause death, cardiovascular death, recurrent myocardial infarction, and a composite outcome of cardiovascular events and procedures. We used logistic regression and reported standardized absolute 5-year risks and risk differences at each landmark year. Among 21 220 first-time myocardial infarction patients, beta-blocker discontinuation was not associated with an increased risk of all-cause death, cardiovascular death, or recurrent myocardial infarction compared with patients continuing beta-blockers (landmark year 5; absolute risk difference [95% confidence interval]), correspondingly; -4.19% [-8.95%; 0.57%], -1.18% [-4.11%; 1.75%], and -0.37% [-4.56%; 3.82%]). Further, beta-blocker discontinuation within two years after myocardial infarction was associated with an increased risk of the composite outcome (landmark year 2; absolute risk [95% confidence interval] 19.87% [17.29%; 22.46%]) compared with continued beta-blocker use (landmark year 2; absolute risk [95% confidence interval] 17.10% [16.34%; 17.87%]), which yielded an absolute risk difference [95% confidence interval] at -2.8% [-5.4%; -0.1%], however, there was no risk difference associated with discontinuation hereafter. Conclusion Discontinuation of beta-blockers one year or later after a myocardial infarction without heart failure was not associated with increased serious adverse events.