Vascular mechanisms of post-COVID-19 conditions: Rho-kinase is a novel target for therapy.

BACKGROUND: In post-coronavirus disease-19 (post-COVID-19) conditions (long COVID), systemic vascular dysfunction is implicated, but the mechanisms are uncertain, and the treatment is imprecise. METHODS AND RESULTS: Patients convalescing after hospitalization for COVID-19 and risk factor matched controls underwent multisystem phenotyping using blood biomarkers, cardiorenal and pulmonary imaging, and gluteal subcutaneous biopsy (NCT04403607). Small resistance arteries were isolated and examined using wire myography, histopathology, immunohistochemistry, and spatial transcriptomics. Endothelium-independent (sodium nitroprusside) and -dependent (acetylcholine) vasorelaxation and vasoconstriction to the thromboxane A2 receptor agonist, U46619, and endothelin-1 (ET-1) in the presence or absence of a RhoA/Rho-kinase inhibitor (fasudil), were investigated. Thirty-seven patients, including 27 (mean age 57 years, 48% women, 41% cardiovascular disease) 3 months post-COVID-19 and 10 controls (mean age 57 years, 20% women, 30% cardiovascular disease), were included. Compared with control responses, U46619-induced constriction was increased (P = 0.002) and endothelium-independent vasorelaxation was reduced in arteries from COVID-19 patients (P < 0.001). This difference was abolished by fasudil. Histopathology revealed greater collagen abundance in COVID-19 arteries {Masson's trichrome (MT) 69.7% [95% confidence interval (CI): 67.8-71.7]; picrosirius red 68.6% [95% CI: 64.4-72.8]} vs. controls [MT 64.9% (95% CI: 59.4-70.3) (P = 0.028); picrosirius red 60.1% (95% CI: 55.4-64.8), (P = 0.029)]. Greater phosphorylated myosin light chain antibody-positive staining in vascular smooth muscle cells was observed in COVID-19 arteries (40.1%; 95% CI: 30.9-49.3) vs. controls (10.0%; 95% CI: 4.4-15.6) (P < 0.001). In proof-of-concept studies, gene pathways associated with extracellular matrix alteration, proteoglycan synthesis, and viral mRNA replication appeared to be upregulated. CONCLUSION: Patients with post-COVID-19 conditions have enhanced vascular fibrosis and myosin light change phosphorylation. Rho-kinase activation represents a novel therapeutic target for clinical trials.

Downregulation of a UDP-Arabinomutase Gene in Switchgrass (Panicum virgatum L.) Results in Increased Cell Wall Lignin While Reducing Arabinose-Glycans.

Background: Switchgrass (Panicum virgatum L.) is a C4 perennial prairie grass and a dedicated feedstock for lignocellulosic biofuels. Saccharification and biofuel yields are inhibited by the plant cell wall's natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and cross-link other cell wall polymers. Grasses predominately have Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP) linked to arabinofuranose (Araf). A family of UDP-arabinopyranose mutase (UAM)/reversible glycosylated polypeptides catalyze the interconversion between UDP-arabinopyranose (UDP-Arap) and UDP-Araf. Results: The expression of a switchgrass arabinoxylan biosynthesis pathway gene, PvUAM1, was decreased via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Southern blot analysis revealed each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise similar in morphology to the non-transgenic control. Cell wall-associated arabinose was decreased in leaves and stems by over 50%, but there was an increase in cellulose. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control. Conclusion: Plants with attenuated PvUAM1 transcript had increased cellulose and lignin in cell walls. A decrease in cell wall-associated arabinose was expected, which was likely caused by fewer Araf residues in the arabinoxylan. The decrease in arabinoxylan may cause a compensation response to maintain cell wall integrity by increasing cellulose and lignin biosynthesis. In cases in which increased lignin is desired, e.g., feedstocks for carbon fiber production, downregulated UAM1 coupled with altered expression of other arabinoxylan biosynthesis genes might result in even higher production of lignin in biomass.

Cognitive outcome after on- and off-pump coronary artery bypass grafting surgery: a systematic review and meta-analysis.

OBJECTIVE: The aim of this study was to compare cognition following coronary artery bypass grafting (CABG) surgery with or without cardiopulmonary bypass (CPB) (on- or off-pump). DESIGN: Systematic review and meta-analysis of randomized control trials comparing cognitive outcome in patients undergoing CABG surgery on- or off-pump as assessed by continuous measures from a battery of 7 psychometric tests. SETTING: Multi-institutional centers performing CABG surgery. PARTICIPANTS: Patients with coronary artery disease requiring CABG surgery. INTERVENTIONS: CABG surgery with or without CPB. MEASUREMENTS AND MAIN RESULTS: A structured literature search identified 13 randomized control trials that included a total of 2,405 patients. Results from 7 psychometric tests were grouped into early (≤3 months) and late (6-12 months) postoperative periods. No significant differences were found between on- and off-pump groups in any of the 7 psychometric tests in either the early (p range 0.21-0.78) or late (p range 0.09-0.93) postoperative period. CONCLUSION: The results suggested that CPB may not be associated with cognitive decline that is associated with CABG surgery.

Antisense down-regulation of 4CL expression alters lignification, tree growth, and saccharification potential of field-grown poplar.

Transgenic down-regulation of the Pt4CL1 gene family encoding 4-coumarate:coenzyme A ligase (4CL) has been reported as a means for reducing lignin content in cell walls and increasing overall growth rates, thereby improving feedstock quality for paper and bioethanol production. Using hybrid poplar (Populus tremula × Populus alba), we applied this strategy and examined field-grown transformants for both effects on wood biochemistry and tree productivity. The reductions in lignin contents obtained correlated well with 4CL RNA expression, with a sharp decrease in lignin amount being observed for RNA expression below approximately 50% of the nontransgenic control. Relatively small lignin reductions of approximately 10% were associated with reduced productivity, decreased wood syringyl/guaiacyl lignin monomer ratios, and a small increase in the level of incorporation of H-monomers (p-hydroxyphenyl) into cell walls. Transgenic events with less than approximately 50% 4CL RNA expression were characterized by patches of reddish-brown discolored wood that had approximately twice the extractive content of controls (largely complex polyphenolics). There was no evidence that substantially reduced lignin contents increased growth rates or saccharification potential. Our results suggest that the capacity for lignin reduction is limited; below a threshold, large changes in wood chemistry and plant metabolism were observed that adversely affected productivity and potential ethanol yield. They also underline the importance of field studies to obtain physiologically meaningful results and to support technology development with transgenic trees.

Can smokers switch from a hospital-based to a community-based stop smoking service? an open-label, randomized trial comparing three referral schemes.

INTRODUCTION: Many hospitals advise their smoking patients to contact a community-based stop smoking service. We investigated how well smokers attend a community-based service after receiving help from a hospital smoking cessation specialist (HSCS). METHODS: In this 55-week, single-blinded trial, 450 consecutive smokers, attending two U.K. hospitals, were randomized. Group A received a brief intervention consisting of a 20-min consultation from an HSCS and leaflets with contact information for their community-based service. Group B received a 60-min consultation, four weekly appointments with the HSCS, and leaflets with contact information for their community-based service. Group C received a 60-min consultation and four weekly appointments with the HSCS and then agreed to attend a scheduled appointment at the nearest community-based service within 1 week. Pharmacotherapy was recommended to all participants, and they were advised to attend the community-based service for ongoing support immediately and at Weeks 5, 12, 26, and 52. At 55 weeks, the HSCS contacted participants again, without warning, for validation. RESULTS: Community-based service attendance at 5 weeks was 7% in Group A, 4% in Group B, and 23% in Group C (p < .001). Over 12-26 weeks, rates of community-based service attendance were 6%-12% in all groups. These rates remained consistently higher in Group C (p < .05) but fell throughout the period to only 3%, 5%, and 7%, respectively, at 52 weeks (p = .26). HSCS attendance at 55 weeks and point prevalence, validated quit rates were 17% for Group A, 20% for Group B, and 22% for Group C (p = .75). DISCUSSION: A specific appointment improves immediate and medium-term attendance at the community-based service, but hospitalized smokers do not switch well to a community-based service following any referral strategy. However, a significant proportion made a repeat visit to the hospital-based program much later on.