The decades-long global trend of urbanization has led to a population that spends increasing amounts of time indoors. Exposure to microbes in buildings, and specifically in dust, is thus also increasing, and has been linked to various health outcomes and to antibiotic resistance genes (ARGs). These are most efficiently screened using DNA sequencing, but this method does not determine which microbes are viable, nor does it reveal whether their ARGs can actually disseminate to other microbes. We have thus performed the first study to: 1) examine the potential for ARG dissemination in indoor dust microbial communities, and 2) validate the presence of detected mobile ARGs in viable dust bacteria. Specifically, we integrated 166 dust metagenomes from 43 different buildings. Sequences were assembled, annotated, and screened for potential integrons, transposons, plasmids, and associated ARGs. The same dust samples were further investigated using cultivation and isolate genome and plasmid sequencing. Potential ARGs were detected in dust isolate genomes, and we confirmed their placement on mobile genetic elements using long-read sequencing. We found 183 ARGs, of which 52 were potentially mobile (associated with a putative plasmid, transposon or integron). One dust isolate related to Staphylococcus equorum proved to contain a plasmid carrying an ARG that was detected metagenomically and confirmed through whole genome and plasmid sequencing. This study thus highlights the power of combining cultivation with metagenomics to assess the risk of potentially mobile ARGs for public health.

Calcification in prosthetic vascular conduits is a major challenge in cardiac and vascular surgery that compromises the long‐term performance of these devices. Significant research efforts have been made to understand the etiology of calcification in the cardiovascular system and to combat calcification in various cardiovascular devices. Novel biomaterial design and tissue engineering strategies have shown promise in preventing or delaying calcification in prosthetic vascular grafts. In this review, we highlight recent advancements in the development of acellular prosthetic vascular grafts with preclinical success in attenuating calcification through advanced biomaterial design. We also discuss the mechanisms of action involved in the designs that will contribute to the further understanding of cardiovascular calcification. Lastly, recent insights into the etiology of vascular calcification will guide the design of future prosthetic vascular grafts with greater potential for translational success.

Introduction: Restenosis is a common cause of vascular device failure. An important contributor is the transdifferentiation of vascular smooth muscle cells (VSMCs) from a contractile to synthetic phenotype. Healthy arteries are innervated by sympathetic nerves to regulate VSMC contractility and phenotype, yet this interaction has been overlooked in pathological vascular remodeling such as restenosis. Hypothesis: Sympathetic denervation of the femoral artery will lead to transdifferentiation of arterial VSMC and pathological remodeling of the arterial structure. Methods: The femoral arteries of male BALB/c mice were surgically exposed and treated with specific dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA) or vehicle for 5 minutes. In the model of long-term denervation, the mice were subcutaneously injected with 6-OHDA or vehicle weekly for 4 weeks. Femoral arteries and peri-adventitial tissue were harvested for histology. Innervation density was calculated as the number of sympathetic nerve fibers (tyrosine hydroxylase-positive) normalized to the medial layer area (α-smooth muscle actin-positive). Extracellular matrix (ECM) composition was visualized with Masson’s trichrome and Verhoeff's elastic staining. Results: One week after surgery, 6-OHDA-treated arteries had a notable reduction in sympathetic nerve density compared to controls (2.9 vs. 11.7 fibers/10,000 μm 2 [P=.22, n=2]). This difference decreased at 2 weeks (6.8 vs. 8.0 fibers/10,000 μm 2 [P=0.50, n=3]) and at 4 weeks (4.4 vs. 5.0 fibers/10,000 μm 2 [P=0.83, n=3]), suggesting nerve recovery. No difference was observed in ECM composition. Tissues harvested at 1 and 4 weeks in the 6-OHDA injection model demonstrate qualitative denervation of the treated limb compared to control. Conclusions: Sympathetic denervation of murine femoral arteries can be achieved by direct surgical application or subcutaneous injection of 6-OHDA. Future work will characterize vascular remodeling after long-term denervation and combine denervation with vascular injury. If a causal relationship can be identified between sympathetic denervation and VSMC pathology, engineering reinnervation could be a viable approach for future graft design.