No abstract

Type 2 diabetes mellitus (T2DM) is a major risk factor for heart disease. Mortality rates after myocardial infarction (MI) are significantly increased in T2DM patients because of dysfunctional left ventricle (LV). However, molecular pathways underlying accelerated heart failure (HF) after MI in T2DM remain unclear. We investigated the underlying mechanisms by inducing MI in a well-established model of T2DM and control mice. Cardiac imaging revealed a significantly decreased global left ventricular ejection fraction in parallel with increased mortality after MI in T2DM mice compared with control mice. Genome-wide mRNA sequencing, immunoblot, electron microscopy, together with immunofluorescence staining for LC3 and p62 indicated an impaired mitophagy in peri-infarct regions of LV in T2DM mice compared with control mice. Furthermore, defective mitophagy was associated with an increased release of mitochondrial DNA, resulting in Aim2 and NLRC4 inflammasome and caspase-I hyperactivation in cardiomyocytes and cardiac macrophages in peri-infarct regions of LV in T2DM mice. Consistent with inflammasome and caspase-I hyperactivation, cardiomyocyte death and IL-18 secretion were increased in T2DM mice. Our results indicate that T2DM aggravates HF after MI through defective mitophagy, associated exaggerated inflammasome activation, cell death, and IL-18 secretion, suggesting that restoring mitophagy and inhibiting inflammasome activation may serve as novel targets for the prevention and treatment of HF in T2DM.

Drug carrier systems based on mesoporous inorganic nanoparticles generally face the problem of fast clearance from bloodstream thus failing in passive and active targeting to cancer tissue. To address this problem, a specific dual PEGylation (DPEG) method for mesoporous silicon (PSi) was developed and studied in vitro and in vivo. The DPEG coating changed significantly the behavior of the nanoparticles in vivo, increasing the circulation half-life from 1 to 241 min. Furthermore, accumulation of the coated particles was mainly taking place in the spleen whereas uncoated nanoparticles were rapidly deposited in the liver. The protein coronas of the particles differed considerably from each other. The uncoated particles had substantially more proteins adsorbed including liver and immune active proteins, whereas the coated particles had proteins capable of suppressing cellular uptake. These reasons along with agglomeration observed in blood circulation were concluded to cause the differences in the behavior in vivo. The biofate of the particles was monitored with magnetic resonance imaging by incorporating superparamagnetic iron oxide nanocrystals inside the pores of the particles making dynamic imaging of the particles feasible. The results of the present study pave the way for further development of the porous inorganic delivery system in the sense of active targeting as the carriers can be easily chemically modified allowing also magnetically targeted delivery and diagnostics.