Short-term preoperative methionine restriction (MetR) shows promise as a translatable strategy to modulate the body's response to surgical injury. Its application, however, to improve post-interventional vascular remodeling remains underexplored. Here, we find that MetR protects from arterial intimal hyperplasia in a focal stenosis model and adverse vascular remodeling after vein graft surgery. RNA sequencing reveals that MetR enhances the brown adipose tissue phenotype in arterial perivascular adipose tissue (PVAT) and induces it in venous PVAT. Specifically, PPAR-α was highly upregulated in PVAT-adipocytes. Furthermore, MetR dampens the post-operative pro-inflammatory response to surgery in PVAT-macrophages and . This study shows for the first time that the detrimental effects of dysfunctional PVAT on vascular remodeling can be reversed by MetR, and identifies pathways involved in browning of PVAT. Furthermore, we demonstrate the potential of short-term pre-operative MetR as a simple intervention to ameliorate vascular remodeling after vascular surgery.

C/D box small nucleolar RNAs (snoRNAs) of the DLK1-DIO3 locus are associated with vascular remodeling and cardiovascular disease. None of these snoRNAs has any known targets yet except for one, AF357425/SNORD113-6. We previously showed that this snoRNA targets mRNAs of the integrin signaling pathway and affects arterial fibroblast function. Here, we aimed to identify whether AF357425/SNORD113-6 can also target small RNAs. We overexpressed or inhibited AF357425 in murine fibroblasts and performed small RNA sequencing. Expression of transfer (t)RNA fragments (tRFs) was predominantly regulated. Compared with overexpression, AF357425 knockdown led to an overall decrease in tRFs but with an enrichment in smaller tRFs (<30 nucleotides). We focused on tRNA leucine anti-codon TAA (tRNA(TAA)), which has a conserved predicted binding site for AF357425/SNORD113-6. Adjacent to this site, the tRNA is cleaved to form tRF in both primary murine and human fibroblasts and in intact human arteries. We show that AF357425/SNORD113-6 methylates tRNA(TAA) and thereby prevents the formation of tRF. Exposing fibroblasts to oxidative or hypoxic stress increased AF357425/SNORD113-6 and tRNA(TAA) expression, but AF357425/SNORD113-6 knockdown did not increase tRF formation under stress even further. Thus, independent of cellular stress, AF357425/SNORD113-6 protects against site-specific fragmentation of tRNA(TAA) via 2'O-ribose-methylation.

Phosphorylcholine (PC) is one of the main oxLDL epitopes playing a central role in atherosclerosis, due to its atherogenic and proinflammatory effects. PC can be cleared by natural IgM antibodies and low levels of these antibodies have been associated with human vein graft (VG) failure. Although PC antibodies are recognized for their anti-inflammatory properties, their effect on intraplaque angiogenesis (IPA) and intraplaque hemorrhage (IPH)-interdependent processes contributing to plaque rupture-are unknown. We hypothesized that new IgG phosphorylcholine antibodies (PC-mAb) could decrease vulnerable lesions in murine VGs.Therefore, hypercholesterolemic male ApoE3*Leiden mice received a (donor) caval vein interposition in the carotid artery and weekly IP injections of (5 mg/kg) PCmAb (n = 11) or vehicle (n = 12) until sacrifice at day 28. We found that PCmAb significantly decreased vein graft media (13%), intima lesion (25%), and increased lumen with 32% compared to controls. PCmAb increased collagen content (18%) and decreased macrophages presence (31%). PCmAb resulted in 23% decreased CD163+ macrophages content in vein grafts whereas CD163 expression was decreased in Hb:Hp macrophages. PCmAb significantly lowered neovessel density (34%), EC proliferation and migration with/out oxLDL stimulation. Moreover, PCmAb enhanced intraplaque angiogenic vessels maturation by increasing neovessel pericyte coverage in vivo (31%). Together, this resulted in a 62% decrease in IPH. PCmAb effectively inhibits murine atherosclerotic lesion formation in vein grafts by reducing IPA and IPH via decreased neovessel density and macrophages influx and increased neovessel maturation. PC-mAb therefore holds promise as a new therapeutic approach to prevent vein graft disease.

Vein grafts (VGs) are used to bypass atherosclerotic obstructions and arteriovenous fistulas (AVFs) as vascular access for hemodialysis. Vascular remodeling governs post-interventional arterialization, but may also induce VG and AVF failure. Although the endpoint characteristics of vascular remodeling are known, the in vivo process and the role of blood flow dynamics has not been fully studied. Therefore, here we non-invasively quantify vascular remodeling and blood flow alterations over time in murine VG and AVF models. C57BL/6J ( = 7, chow diet) and atherosclerosis-prone ApoE3*Leiden ( = 7) mice underwent VG surgery. Ultrasound imaging was performed at 3, 7, 14, 21, and 28 days post-surgery. C57BL/6J mice ( = 8) received AVF surgery. Ultrasound imaging was performed at 7 and 14 days post-surgery. The luminal volume increased by 42% in the VGs of C57BL/6J and 38% in the VGs of ApoE3*Leiden mice at 28 days relative to 3 days post-surgery. Longitudinally, an 82% increase in wall volume and 76% increase in outward remodeling was found in the ApoE3*Leiden mice, with a constant wall size in C57BL/6J mice. Proximally, the pulsatility index, resistive index, and peak systolic velocity decreased longitudinally in both groups. Distally, the maximum acceleration increased with 56% in C57BL/6J VGs. Among the AVFs, 50% showed maturation after 7 days, based on a novel flow-criterium of 23 mL/min. Distinct flow patterns were observed at the anastomotic site and inflow artery of the AVFs relative to the control carotid arteries. Vascular remodeling can be quantified by ultra-high-frequency ultrasound imaging over time in complex animal models, via three-dimensional structural parameters and site-specific hemodynamic indices.